Additional file 6 of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

The concatenated tree based on six housekeeping MLSA genes (including trpB; right) and five MLSA gene sequences (rpoD, dnaK, tuf, gyrB, atpA; left). The arrow shows disagreement concerning the position of strain G2 (B399) between the two trees. (PDF 77 kb)

Association of colony morphotypes with virulence, growth and resistance against protozoan predation in the fish pathogen Flavobacterium columnare.

Many opportunistic pathogens can alternate between inside- and outside-host environments during their life cycle. The opportunistic fish pathogen Flavobacterium columnare is an inhabitant of the natural microbial community and causes significant yearly losses in aquaculture worldwide. The bacterium grows in varying colony morphotypes that are associated with either virulence (rhizoid type) or resistance to starvation and phages (rough type). Rough type strains can arise spontaneously or can be induced by phage infection. To identify the determinants of morphotype fitness, we measured virulence, growth parameters, biofilm-forming ability and resistance to amoeba and ciliate predation of both…

Environmentally triggered evolutionary cascade across trophic levels in an experimental phage-bacteria-insect system

Abstract Environmental changes can cause strong cascading effects in species communities due to altered biological interactions between species (Zarnetske et al., 2012). Highly specialized interactions arising from the co-evolution of hosts and parasites, such as bacteria and phages, and short generation times of these species could rapidly lead to considerable evolutionary changes in their biotic interactions (Kerr, 2012; Buck and Ripple, 2017), with potential large-scale ramifications to other trophic levels. Here we report experimental evidence of cascading environmental effects across trophic levels in an experimental system where phage-bacteria coevolution in an abiotically altered env…

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

A mechanistic underpinning for sigmoid dose-dependent infection

Effects of acclimation time and epigenetic mechanisms on growth of Neurospora in fluctuating environments

AbstractReaction norms or tolerance curves have often been used to predict how organisms deal with fluctuating environments. A potential drawback is that reaction norms measured in different constant environments may not capture all aspects of organismal responses to fluctuating environments. We examined growth of the filamentous fungusNeurospora crassain fluctuating temperatures and tested if growth in fluctuating temperatures can be explained simply by growth in different constant temperatures or if more complex models are needed. In addition, as previous studies on fluctuating environments have revealed that past temperatures that organisms have experienced can affect their response to c…

No uniform associations between parasite prevalence and environmental nutrients

The resource quality of the host has been shown to affect parasite transmission success, prevalence, and virulence. Seasonal availability of environmental nutrients alters density and stoichiometric quality (carbon–nutrient ratios) of both producers and consumers, suggesting that nutrient availability may drive fluctuations in parasite prevalence patterns observed in nature. We examined the interactions between the population dynamics of a keystone herbivore, Daphnia, and its parasites, and their associations with water nutrient concentrations, resource quantity and quality, and other environmental variables (temperature, pH, oxygen concentration) in a small lake, using general linear model…

FLUCTUATING TEMPERATURE LEADS TO EVOLUTION OF THERMAL GENERALISM AND PREADAPTATION TO NOVEL ENVIRONMENTS

Environmental fluctuations can select for generalism, which is also hypothesized to increase organisms' ability to invade novel environments. Here, we show that across a range of temperatures, opportunistic bacterial pathogen Serratia marcescens that evolved in fluctuating temperature (daily variation between 24°C and 38°C, mean 31°C) outperforms the strains that evolved in constant temperature (31°C). The growth advantage was also evident in novel environments in the presence of parasitic viruses and predatory protozoans, but less clear in the presence of stressful chemicals. Adaptation to fluctuating temperature also led to reduced virulence in Drosophila melanogaster host, which suggests…

Experimental evolution in fluctuating environments: tolerance measurements at constant temperatures incorrectly predict the ability to tolerate fluctuating temperatures

The ability to predict the consequences of fluctuating environments on species distribution and extinction often relies on determining the tolerances of species or genotypes in different constant environments (i.e. determining tolerance curves). However, very little is known about the suitability of measurements made in constant environments to predict the level of adaptation to rapidly fluctuating environments. To explore this question, we used bacterial clones adapted to constant or fluctuating temperatures and found that measurements across a range of constant temperatures did not indicate any adaptation to fluctuating temperatures. However, adaptation to fluctuating temperatures was onl…

Luonnon monimuotoisuus ja vihreä elvytys

Suomi on toistaiseksi selvinnyt koronaviruksen (COVID-19) aiheuttamasta kriisistä taloudellisesti verrokkimaita paremmin, mutta työllisyystilanne on silti heikentynyt ympäri maata ja talouden ennustetaan supistuvan noin 4,7 prosenttia vuonna 20201. Negatiivisten talousvaikutusten minimoimiseksi hallitus on suuntaamassa EU:n elpymisvälineestä varoja käytettäväksi toimiin, jotka samanaikaisesti auttavat ratkaisemaan aikamme kahta merkittävää kriisiä: ilmastonmuutosta ja luontokatoa. Kyse on aidosti vakavista kriiseistä. Esimerkiksi Maailman talousfoorumi on listannut luonnon ekosysteemien romahduksen ja ilmastonmuutoksen torjunnan epäonnistumisen sekä vaikutuksiltaan että todennäköisyydeltään…

Within-host evolution decreases virulence in an opportunistic bacterial pathogen

Abstract Background Pathogens evolve in a close antagonistic relationship with their hosts. The conventional theory proposes that evolution of virulence is highly dependent on the efficiency of direct host-to-host transmission. Many opportunistic pathogens, however, are not strictly dependent on the hosts due to their ability to reproduce in the free-living environment. Therefore it is likely that conflicting selection pressures for growth and survival outside versus within the host, rather than transmission potential, shape the evolution of virulence in opportunists. We tested the role of within-host selection in evolution of virulence by letting a pathogen Serratia marcescens db11 sequent…

Keskeiset keinot luontokadon pysäyttämiseksi

Sanna Marinin hallitus on sitoutunut luonnon monimuotoisuuden tilan parantamiseen ja luontokadon pysäyttämiseen. Lupaus on äärimmäisen tärkeä. Luonnon ekosysteemien heikennys uhkaa elintärkeiden eko-systeemipalveluiden tuotantoa sekä ihmisten terveyttä, hyvinvointia ja turvallisuutta. Maailman talousfoorumi on nostanut luontokadon viiden vakavimman ihmiskuntaa uhkaavan riskin joukkoon. Myös Suomen luontotyyppien ja lajiston uhanalaisuustilanne on hälyttävä. Hallituksen kehysriihessä päätetään hallitusohjelman toteuttamisesta ja lunastetaan vuoden 2019 eduskuntavaalien lupaukset luonto- ja ilmastotoimista. Myös EU:n uusi biodiversiteettistrategia velvoittaa Suomea panostamaan luonnonsuojeluu…

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Rapid evolutionary adaptation to elevated salt concentrations in pathogenic freshwater bacteria Serratia marcescens.

Rapid evolutionary adaptions to new and previously detrimental environmental conditions can increase the risk of invasion by novel pathogens. We tested this hypothesis with a 133-day-long evolutionary experiment studying the evolution of the pathogenic Serratia marcescens bacterium at salinity niche boundary and in fluctuating conditions. We found that S. marcescens evolved at harsh (80 g/L) and extreme (100 g/L) salt conditions had clearly improved salt tolerance than those evolved in the other three treatments (ancestral conditions, nonsaline conditions, and fluctuating salt conditions). Evolutionary theories suggest that fastest evolutionary changes could be observed in intermediate sele…

Täsmäratkaisuja kestävään tulevaisuuteen : suosituksia planetaarisen hyvinvoinnin tukemiseen poliittisessa ohjelmatyössä

Peer reviewed

Environmental Fluctuations Drive Species' Competitive Success in Experimental Invasions

Climate change is presumed to increase both the number and frequency of fluctuations in environmental conditions. Fluctuations can affect the ecological and evolutionary processes that make species more successful competitors. For example, fluctuating conditions can create selection pressures for traits that are profitable in adaptation to fast climate change. On an ecological timescale, environmental fluctuations can facilitate species competitive success by reducing other species’ population sizes. Climate change could then enhance species invasions into new areas if fluctuation-adapted invaders displace their native competitors in chancing environments. We tested experimentally whether f…

Thermal Tolerance is linked with Virulence in a Fish Pathogen

ABSTRACTAlthough increase in temperatures may boost the number of pathogens, a complex process involving the interaction of a susceptible host, a virulent strain, and environmental factors would influence disease virulence in unpredictable ways. Here we explored if the virulence of an environmentally growing opportunistic fish pathogen,Flavobacterium columnare, would be malleable to evolutionary changes via correlated selection on thermal tolerance. Virulence among the strains increased over years, but tolerance to higher temperatures was associated with reduced virulence. Our results suggest that observed increase in frequency of columnaris epidemics over the last decade is most likely ass…

Invasion triple trouble : environmental fluctuations, fluctuation-adapted invaders and fluctuation-mal-adapted communities all govern invasion success

AbstractIt has been suggested that climate change will lead to increased environmental fluctuations, which will undoubtedly have evolutionary consequences for all biota. For instance, fluctuations can directly increase the risk of invasions of alien species into new areas, as these species have repeatedly been proposed to benefit from disturbances. At the same time increased environmental fluctuations may also select for better invaders. However, selection by fluctuations may also influence the resistance of communities to invasions, which has rarely been tested. We tested eco-evolutionary dynamics of invasion with bacterial clones, evolved either in constant or fluctuating temperatures, an…

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Table S1 and S2 from Heat hardening capacity in Drosophila melanogaster is life stage specific and juveniles show the highest plasticity

Table S1. Tukey's post-hoc test results after false discovery rate correction to compare the heat resistance of hardened and non-hardened individuals at different life stages exposed to 25 ºC compared to corresponding 37 ºC test temperature. The table shows the sum of square (SS), Fdf ratio and the p-values.; Table S2. Tukey's post-hoc test results after false discovery rate (FDR) correction to compare the heat resistance of different life stages at different test temperatures. The table shows the Fdf ratio and the p-values with p < 0.05 in bold.

Evolution of bacterial life-history traits is sensitive to community structure

Very few studies have experimentally assessed the evolutionary effects of species interactions within the same trophic level. Here we show that when Serratia marcescens evolve in multispecies communities, their growth rate exceeds the growth rate of the bacteria that evolved alone, whereas the biomass yield gets lower. In addition to the community effects per se, we found that few species in the communities caused strong effects on S. marcescens evolution. The results indicate that evolutionary responses (of a focal species) are different in communities, compared to species evolving alone. Moreover, selection can lead to very different outcomes depending on the community structure. Such con…

The effect of a temperature-sensitive prophage on the evolution of virulence in an opportunistic bacterial pathogen

AbstractViruses are key actors of ecosystems and have major impacts on global biogeochemical cycles. Prophages deserve particular attention as they are ubiquitous in bacterial genomes and can enter a lytic cycle when triggered by environmental conditions. We explored how temperature affects the interactions between prophages and other biological levels by using an opportunistic pathogen, the bacterium Serratia marcescens, that harbours several prophages and that had undergone an evolution experiment under several temperature regimes. We found that the release of one of the prophages was temperature-sensitive and malleable to evolutionary changes. We further discovered that the virulence of …

Systematic Comparison of Epidemic and Non-Epidemic Carbapenem Resistant Klebsiella pneumoniae Strains

Over the past few decades, extensively drug resistant (XDR) resistant Klebsiella pneumoniae has become a notable burden to healthcare all over the world. Especially carbapenemase-producing strains are problematic due to their capability to withstand even last resort antibiotics. Some sequence types (STs) of K. pneumoniae are significantly more prevalent in hospital settings in comparison to other equally resistant strains. This provokes the question whether or not there are phenotypic characteristics that may render certain K. pneumoniae more suitable for epidemic dispersal between patients, hospitals, and different environments. In this study, we selected seven epidemic and non-epidemic ca…

Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen

Phenotypic variation is suggested to facilitate the persistence of environmentally growing pathogens under environmental change. Here, we hypothesized that the intensive farming environment induces higher phenotypic variation in microbial pathogens than natural environment, because of high stochasticity for growth and stronger survival selection compared to the natural environment. We tested the hypothesis with an opportunistic fish pathogen Flavobacterium columnare isolated either from fish farms or from natural waters. We measured growth parameters of two morphotypes from all isolates in different resource concentrations and two temperatures relevant for the occurrence of disease epidemic…

The Good-Genes and Compatible-Genes Benefits of Mate Choice

Genetic benefits from mate choice could be attained by choosing mates with high heritable quality (“good genes”) and that are genetically compatible (“compatible genes”). We clarify the conceptual and empirical framework for estimating genetic benefits of mate choice, stressing that benefits must be measured from offspring fitness because there are no unequivocal surrogates for genetic quality of individuals or for compatibility of parents. We detail the relationship between genetic benefits and additive and nonadditive genetic variance in fitness, showing that the benefits have been overestimated in previous verbal treatments. We point out that additive benefits readily arise from nonaddit…

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Town population size and structuring into villages and households drive infectious disease risks in pre-healthcare Finland

Social life is often considered to cost in terms of increased parasite or pathogen risk. However, evidence for this in the wild remains equivocal, possibly because populations and social groups are often structured, which affects the local transmission and extinction of diseases. We test how the structuring of towns into villages and households influenced the risk of dying from three easily diagnosable infectious diseases—smallpox, pertussis and measles—using a novel dataset covering almost all of Finland in the pre-healthcare era (1800–1850). Consistent with previous results, the risk of dying from all three diseases increased with the local population size. However, the division of towns …

The relationship between stocking eggs in boreal spawning rivers and the abundance of brown trout parr

Abstract Stocking with eggs has been widely used as a management measure to support degraded salmonid stocks. In Finland, Atlantic salmon and both sea-migrating and lake-migrating brown trout are stocked as eggs, alevins, fry, parr, and smolt, whereas trout are also stocked as mature fish. The aim of this stocking is to improve catches and to support collapsed spawning stocks. We assessed the success of stocking with brown trout eggs in a study of 17 Finnish boreal forest rivers, of which 9 were subject to egg stocking. All rivers contained some naturally spawning trout. In 16 rivers, including non-stocking years and unstocked rivers, egg stocking did not increase the total (wild and stocke…

Intensive aquaculture selects for increased virulence and interference competition in bacteria

Although increased disease severity driven by intensive farming practices is problematic in food production, the role of evolutionary change in disease is not well understood in these environments. Experiments on parasite evolution are traditionally conducted using laboratory models, often unrelated to economically important systems. We compared how the virulence, growth and competitive ability of a globally important fish pathogen, Flavobacterium columnare , change under intensive aquaculture. We characterized bacterial isolates from disease outbreaks at fish farms during 2003–2010, and compared F. columnare populations in inlet water and outlet water of a fish farm during the 2010 outbre…

Jatkuvapeitteisen metsänkäsittelyn ympäristö- ja talousvaikutukset : Luontopaneelin yhteenveto ja suositukset luontopolitiikan suunnittelun ja päätöksenteon tueksi

Raportin yhteenveto LUONTOPANEELIN KESKEISET HUOMIOT JA SUOSITUKSET • Jatkuvapeitteisen metsänkäsittelyn osuutta kannattaa merkittävästi kasvattaa taloudellisista syistä. Valtaosa suomalaisista ja pohjoismaisista jatkuvapeitteistä ja jaksollista metsänkäsittelyä vertailevista tutkimuksista koskee puuntuotantomäärää metsänkäsittelyn taloudellisen tuloksen sijaan. Mahdollisimman suuri puuntuotannon määrä voi olla edullista puun ostajalle, mutta se ei välttämättä ole taloudellisesti paras vaihtoehto maanomistajan eli puun tuottajan eikä myöskään puun tuottajien ja ostajien yhteenlasketun taloudellisen tuloksen eli kansantalouden näkökulmasta. Vaikka hakkuukertymät voivat jatkuvapeitteisessä me…

Coincidental loss of bacterial virulence in multi-enemy microbial communities.

The coincidental virulence evolution hypothesis suggests that outside-host selection, such as predation, parasitism and resource competition can indirectly affect the virulence of environmentally-growing bacterial pathogens. While there are some examples of coincidental environmental selection for virulence, it is also possible that the resource acquisition and enemy defence is selecting against it. To test these ideas we conducted an evolutionary experiment by exposing the opportunistic pathogen bacterium Serratia marcescens to the particle-feeding ciliate Tetrahymena thermophila, the surfacefeeding amoeba Acanthamoeba castellanii, and the lytic bacteriophage Semad11, in all possible combi…

Heat hardening capacity in Drosophila melanogaster is life stage-specific and juveniles show the highest plasticity

Variations in stress resistance and adaptive plastic responses during ontogeny have rarely been addressed, despite the possibility that differences between life stages can affect species' range margins and thermal tolerance. Here, we assessed the thermal sensitivity and hardening capacity of Drosophila melanogaster across developmental stages from larval to the adult stage. We observed strong differences between life stages in heat resistance, with adults being most heat resistant followed by puparia , pupae and larvae . The impact of heat hardening (1 h at 35°C) on heat resistance changed during ontogeny, with the highest positive effect of hardening observed in puparia and pupae and the …

Temperature-dependent mutational robustness can explain faster molecular evolution at warm temperatures, affecting speciation rate and global patterns of species diversity

Distribution of species across the Earth shows strong latitudinal and altitudinal gradients with the number of species decreasing with declining temperatures. While these patterns have been recognized for well over a century, the mechanisms generating and maintaining them have remained elusive. Here, we propose a mechanistic explanation for temperature-dependent rates of molecular evolution that can influence speciation rates and global biodiversity gradients. Our hypothesis is based on the effects of temperature and temperature-adaptation on stability of proteins and other catalytic biomolecules. First, due to the nature of physical forces between biomolecules and water, stability of biomo…

Heterozygote advantage and pleiotropy contribute to intraspecific color trait variability

The persistence of intrapopulation phenotypic variation typically requires some form of balancing selection because drift and directional selection eventually erode genetic variation. Heterozygote advantage remains a classic explanation for the maintenance of genetic variation in the face of selection. However, examples of heterozygote advantage, other than those associated with disease resistance, are rather uncommon. Across most of its distribution, males of the aposematic moth Arctia plantaginis have two hindwing phenotypes determined by a heritable one locus-two allele polymorphism (genotypes: WW/Wy = white morph, yy = yellow morph). Using genotyped moths, we show that the presence of o…

The good-genes and compatible-genes benefits of mate choice.

Genetic benefits from mate choice could be attained by choosing mates with high heritable quality ("good genes") and that are genetically compatible ("compatible genes"). We clarify the conceptual and empirical framework for estimating genetic benefits of mate choice, stressing that benefits must be measured from offspring fitness because there are no unequivocal surrogates for genetic quality of individuals or for compatibility of parents. We detail the relationship between genetic benefits and additive and nonadditive genetic variance in fitness, showing that the benefits have been overestimated in previous verbal treatments. We point out that additive benefits readily arise from nonaddit…

Ecological conditions alter cooperative behaviour and its costs in a chemically defended sawfly

The evolution of cooperation and social behaviour is often studied in isolation from the ecology of organisms. Yet, the selective environment under which individuals evolve is much more complex in nature, consisting of ecological and abiotic interactions in addition to social ones. Here, we measured the life-history costs of cooperative chemical defence in a gregarious social herbivore, Diprion pini pine sawfly larvae, and how these costs vary under different ecological conditions. We ran a rearing experiment where we manipulated diet (resin content) and attack intensity by repeatedly harassing larvae to produce a chemical defence. We show that forcing individuals to allocate more to coope…

Genetics of condition and sexual selection

FM Tarmo Ketolan ekologian ja ympäristönhoidon väitöskirjan ”Genetics of Condition and Sexual Selection” (Kunnon ja seksuaalivalinnan genetiikka) tarkastustilaisuus Jyväskylän yliopistossa. Vastaväittäjänä professori Juha Merilä (Helsingin yliopisto) ja kustoksena dosentti Janne Kotiaho.Linkki väitöksen pdf-versioon tiedotteen lopussa.FM Tarmo Ketola havaitsi väitöstutkimuksessaan, että geneettisesti huonolaatuiset sirkkayksilöt pystyvät käyttämään vähemmän energiaa aktiviteetteihin kuin hyvälaatuiset. Koska sisäsiitos lisäsi perusenergiankulutusta eli ruumiintoimintojen ylläpitoon kulutettua energiaa, se heikensi yksilöiden kuntoa.– Aiemmin on oletettu, että huonolaatuisilla yksilöillä on …

Is reproduction really costly? Energy metabolism of bank vole (Clethrionomys glareolus) females through the reproductive cycle

Energetic requirements during reproduction are important determinants of the onset of reproduction and of breeding strategy (e.g., breeding post-partum) and therefore affect female reproductive output in seasonally varying environments. To balance the energetic needs of breeding with energy availability, females must optimize energy allocation between their own energy use and energy allocated to their litter. Here, we studied energetic costs and potential energetic trade-offs of reproduction in female bank voles (Clethrionomys glareolus). We measured energy consumption, i.e., metabolic rates as determined from carbon dioxide production of females either with their pups (breeding unit) to fi…

Manipulating genetic architecture to reveal fitness relationships

Constant, cycling, hot and cold thermal environments: strong effects on mean viability but not on genetic estimates

It has frequently been suggested that trait heritabilities are environmentally sensitive, and there are genetic trade-offs between tolerating different environments such as hot and cold or constant and fluctuating temperatures. Future climate predictions suggest an increase in both temperatures and their fluctuations. How species will respond to these changes is uncertain, particularly as there is a lack of studies which compare genetic performances in constant vs. fluctuating environments. In this study, we used a nested full-sib/half-sib breeding design to examine how the genetic variances and heritabilities of egg-to-adult viability differ at high and low temperatures with and without da…

Inbreeding depression in intraspecific metabolic scaling

Metabolic scaling (i.e., the relationship between the size and metabolic rate of organisms) has been suggested to explain a large variety of biological patterns from individual growth to species diversity. However, considerable disagreement remains regarding the underlying causes of metabolic scaling patterns, and what these patterns are. As in all biology, understanding metabolic scaling will require understanding its evolution by natural selection. We searched for evidence of natural selection on metabolic scaling indirectly by manipulating the genetic quality of male and female Drosophila montana flies with induced mutations and inbreeding, building on the notion that mutations and inbre…

The seasonality of three childhood infections in a pre-industrial society without schools

AbstractBackgroundThe burden of many infectious diseases varies seasonally and a better understanding of the drivers of infectious disease seasonality would help to improve public health interventions. For directly transmitted highly-immunizing childhood infections, the leading hypothesis is that seasonality is strongly driven by social gatherings imposed by schools, with maxima and minima during school terms and holidays respectively. However, we currently have a poor understanding of the seasonality of childhood infections in societies without schools and whether these are driven by human social gatherings. Here, we used unique nationwide data consisting of >40 epidemics over 100 years…

Quantitative genetics of temperature performance curves of Neurospora crassa

AbstractEarth’s temperature is increasing due to anthropogenic CO2emissions; and organisms need either to adapt to higher temperatures, migrate into colder areas, or face extinction. Temperature affects nearly all aspects of an organism’s physiology via its influence on metabolic rate and protein structure, therefore genetic adaptation to increased temperature may be much harder to achieve compared to other abiotic stresses. There is still much to be learned about the evolutionary potential for adaptation to higher temperatures, therefore we studied the quantitative genetics of growth rates in different temperatures that make up the thermal performance curve of the fungal model systemNeuros…

Evolutionary rescue at different rates of environmental change is affected by trade-offs between short-term performance and long-term survival.

As climate change accelerates and habitats free from anthropogenic impacts diminish, populations are forced to migrate or to adapt quickly. Evolutionary rescue (ER) is a phenomenon, in which a population is able to avoid extinction through adaptation. ER is considered to be more likely at slower rates of environmental change. However, the effects of correlated characters on evolutionary rescue are seldom explored yet correlated characters could play a major role in ER. We tested how evolutionary background in different fluctuating environments and the rate of environmental change affect the probability of ER by exposing populations of the bacteria Serratia marcescens to two different rates …

Propagule pressure increase and phylogenetic diversity decrease community’s susceptibility to invasion

Background Invasions pose a large threat to native species, but the question of why some species are more invasive, and some communities more prone to invasions than others, is far from solved. Using 10 different three-species bacterial communities, we tested experimentally if the phylogenetic relationships between an invader and a resident community and the propagule pressure affect invasion probability. Results We found that greater diversity in phylogenetic distances between the members of resident community and the invader lowered invasion success, and higher propagule pressure increased invasion success whereas phylogenetic distance had no clear effect. In the later stages of invasion,…

Experimental evolution of evolutionary potential in fluctuating environments

Variation is the raw material for evolution. Evolutionary potential is determined by the amount of genetic variation, but evolution can also alter the visibility of genetic variation to natural selection. Fluctuating environments are suggested to maintain genetic variation but they can also affect environmental variance, and thus, the visibility of genetic variation to natural selection. However, experimental studies testing these ideas are relatively scarce. In order to determine differences in evolutionary potential we quantified variance attributable to population, genotype and environment for populations of the bacterium Serratia marcescens. These populations had been experimentally evo…

Application of high resolution melting assay (HRM) to study temperature-dependent intraspecific competition in a pathogenic bacterium

AbstractStudies on species’ responses to climate change have focused largely on the direct effect of abiotic factors and in particular temperature, neglecting the effects of biotic interactions in determining the outcome of climate change projections. Many microbes rely on strong interference competition; hence the fitness of many pathogenic bacteria could be a function of both their growth properties and intraspecific competition. However, due to technical challenges in distinguishing and tracking individual strains, experimental evidence on intraspecific competition has been limited so far. Here, we developed a robust application of the high-resolution melting (HRM) assay to study head-to…

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Resource availability and competition shape the evolution of survival and growth ability in a bacterial community

Resource availability is one of the main factors determining the ecological dynamics of populations or species. Fluctuations in resource availability can increase or decrease the intensity of resource competition. Resource availability and competition can also cause evolutionary changes in life-history traits. We studied how community structure and resource fluctuations affect the evolution of fitness related traits using a two-species bacterial model system. Replicated populations of Serratia marcescens (copiotroph) and Novosophingobium capsulatum (oligotroph) were reared alone or together in environments with intergenerational, pulsed resource renewal. The comparison of ancestral and evol…

Energy use, diapause behaviour and northern range expansion potential in the invasive Colorado potato beetle

Summary 1. As organisms expand their range towards northern latitudes they will encounter selective factors like harsh winter conditions. The ability to cope with and adapt to harsh winters may depend on the variability and evolutionary potential of relevant traits. 2. One adaptation in insects is winter diapause. It is characterized by changes in physiology, behaviour or in both. Physiological changes include lowered metabolic rate that enhances survival by saving limited energy reserves during overwintering. Active behavioural changes like burrowing into the soil allow individuals to escape harsh conditions. 3. We examined variation in overwintering body mass, resting metabolic rate (CO2 …

Temperature-dependent mutational robustness can explain faster molecular evolution at warm temperatures, affecting speciation rate and global patterns of species diversity

Distribution of species across the Earth shows strong latitudinal and altitudinal gradients with the number of species decreasing with declining temperatures. While these patterns have been recognized for well over a century, the mechanisms generating and maintaining them have remained elusive. Here, we propose a mechanistic explanation for temperature-dependent rates of molecular evolution that can influence speciation rates and global biodiversity gradients. Our hypothesis is based on the effects of temperature and temperature-adaptation on stability of proteins and other catalytic biomolecules. First, due to the nature of physical forces between biomolecules and water, stability of biomo…

Genetic compatibility and sexual selection

In a recent review in TREE [1], Mays and Hill discuss the interface between sexual selection for good genes (i.e. female choice based on traits indicating heritable fitness) and sexual selection for genetic compatibility (i.e. how well the genes of the parents function together in their offspring). We feel that the scope of their contribution is somewhat limited, primarily because they implicitly equate genetic compatibility with genetic dissimilarity. Compatibility does, however, not equal dissimilarity.

Additional file 1 of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Site, year of isolation, source of isolation (fish or water), location of isolation, host species, sequence type (ST), and allelic profile data for the 83Â F. columnare strains from Finland analyzed by MLST. (DOCX 46 kb)

Broad thermal tolerance is negatively correlated with virulence in an opportunistic bacterial pathogen

Predicting the effects of global increase in temperatures on disease virulence is challenging, especially for environmental opportunistic bacteria, because pathogen fitness may be differentially affected by temperature within and outside host environment. So far, there is very little empirical evidence on the connections between optimal temperature range and virulence in environmentally growing pathogens. Here, we explored whether the virulence of an environmentally growing opportunistic fish pathogen, Flavobacterium columnare, is malleable to evolutionary changes via correlated selection on thermal tolerance. To this end, we experimentally quantified the thermal performance curves (TPCs) f…

EVOLUTION OF HSP90 EXPRESSION IN TETRAHYMENA THERMOPHILA (PROTOZOA, CILIATA) POPULATIONS EXPOSED TO THERMALLY VARIABLE ENVIRONMENTS

Evolutionary consequences of thermally varying environments were studied in the ciliated protozoan Tetrahymena thermophila. Replicated lines were propagated for 60 days, a maximum of 500 generations, in stable, slowly fluctuating (red spectrum), and rapidly fluctuating (blue spectrum) temperatures. The red and blue fluctuations had a dominant period length of 15 days and two hours, respectively. The mean temperature of all time series was 25 degrees C and the fluctuating temperatures had the same minimum (10 degrees C), maximum (40 degrees C), and variance. During the experiment, population sizes and biomasses were monitored at three-day intervals. After the experiment, carrying capacity an…

A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Background Columnaris disease caused by Flavobacterium columnare is a serious problem in aquaculture, annually causing large economic losses around the world. Despite considerable research, the molecular epidemiology of F. columnare remains poorly understood. Methods We investigated the population structure and spatiotemporal changes in the genetic diversity of F. columnare population in Finland by using a multilocus sequence typing (MLST) and analysis (MLSA) based on DNA sequence variation within six housekeeping genes. A total of 83 strains of F. columnare were collected from eight different areas located across the country between 2003 and 2012. Results Partial sequencing of six housekee…

Soiden ennallistamisen suoluonto-, vesistö- ja ilmastovaikutukset : Luontopaneelin yhteenveto ja suositukset luontopolitiikan suunnittelun ja päätöksenteon tueksi

Suomen alkuperäisestä 10,4 miljoonan hehtaarin suoalasta yli puolet on ojitettu metsä- ja maatalouden sekä turvetuotannon tarpeisiin. Etelä-Suomessa ojitus on ollut voimakkainta: keskimäärin noin 75 prosenttia ja monin paikoin vielä suurempi osa soista on ojitettu. Suot ovat Euroopan luontotyypeistä kaikkein uhanalaisin luontotyyppiryhmä ja Suomella on erityisvastuu soiden suojelusta. Kaikkiaan 54 prosenttia Suomen 50 suoluontotyypistä on uhanalaisia ja lisäksi 20 prosenttia on silmällä-pidettäviä. Ensisijaisesti Suomen soilla elävistä lajeista 11 prosenttia eli yhteensä 120 lajia on uhanalaisia. Uhanalaisilla lajeilla ja luontotyypeillä on korkea riski hävitä Suomesta. Mittava ojitus näkyy…

Marked Neurospora crassa strains for competition experiments and Bayesian methods for fitness estimates

AbstractThe filamentous fungusNeurospora crassa, a model microbial eukaryote, has a life cycle with many features that make it suitable for studying experimental evolution. However, it has lacked a general tool for estimating relative fitness of different strains in competition experiments. To remedy this need, we constructedN. crassastrains that contain a modifiedcsr-1locus and developed an assay for detecting the proportion of the marked strain using a post PCR high resolution melting assay. DNA extraction from spore samples can be performed on 96-well plates, followed by a PCR step, which allows many samples to be processed with ease. Furthermore, we suggest a Bayesian approach for estim…

Adaptation to environmental stress at different timescales

Environments are changing rapidly, and to cope with these changes, organisms have to adapt. Adaptation can take many shapes and occur at different speeds, depending on the type of response, the trait, the population, and the environmental conditions. The biodiversity crisis that we are currently facing illustrates that numerous species and populations are not capable of adapting with sufficient speed to ongoing environmental changes. Here, we discuss current knowledge on the ability of animals and plants to adapt to environmental stress on different timescales, mainly focusing on thermal stress and ectotherms. We discuss within-generation responses that can be fast and induced within minute…

The effect of a temperature-sensitive prophage on the evolution of virulence in an opportunistic bacterial pathogen.

https://doi.org/10.1111/mec.16638 Abstract Viruses are key actors of ecosystems and have major impacts on global biogeochemical cycles. Prophages deserve particular attention as they are ubiquitous in bacterial genomes and can enter a lytic cycle when triggered by environmental conditions. We explored how temperature affects the interactions between prophages and other biological levels by using an opportunistic pathogen, the bacterium Serratia marcescens, that harbours several prophages and that had undergone an evolution experiment under several temperature regimes. We found that the release of one of the prophages was temperature-sensitive and malleable to evolutionary changes. We furthe…

DOES ENVIRONMENTAL ROBUSTNESS PLAY A ROLE IN FLUCTUATING ENVIRONMENTS?

Fluctuating environments are expected to select for individuals that have highest geometric fitness over the experienced environments. This leads to the prediction that genetically determined environmental robustness in fitness, and average fitness across environments should be positively genetically correlated to fitness in fluctuating environments. Because quantitative genetic experiments resolving these predictions are missing, we used a full-sib, half-sib breeding design to estimate genetic variance for egg-to-adult viability in Drosophila melanogaster exposed to two constant or fluctuating temperatures that were above the species' optimum temperature, during development. Viability in t…

Inbreeding depression in the effects of body mass on energy use

Large organisms have higher metabolic rates than small organisms but, if we compare their relative metabolic rates (i.e. per gram of tissue), this relationship is very often reversed. The pervasiveness of this phenomenon, called metabolic scaling, has attracted several theoretical explanations, and also produced lingering debate over whether metabolic scaling is a physically constrained and universally constant phenomenon or a more variable and evolutionarily malleable trait. To bring novel insights to this debate, we manipulated male Gryllodes sigillatus crickets’ coefficients of inbreeding to determine whether metabolic scaling is sensitive to the manipulation of genetic quality. Because …

Different food sources elicit fast changes to bacterial virulence

Environmentally transmitted, opportunistic bacterial pathogens have a life cycle that alternates between hosts and environmental reservoirs. Resources are often scarce and fluctuating in the outside-host environment, whereas overcoming the host immune system could allow pathogens to establish a new, resource abundant and stable niche within the host. We tested if short-term exposure to different outside-host resource types and concentrations affect Serratia marcescens —(bacterium)'s virulence in Galleria mellonella (moth). As expected, virulence was mostly dictated by the bacterial dose, but we also found a clear increase in virulence when the bacterium had inhabited a low (versus high) re…

Can evolution of sexual dimorphism be triggered by developmental temperatures?

Genetic prerequisites for the evolution of sexual dimorphism, sex-specific heritabilities and low or negative genetic correlations between homologous traits in males and females are rarely found. However, sexual dimorphism is evolving rapidly following environmental change, suggesting that sexual dimorphism and its genetic background could be environmentally sensitive. Yet few studies have explored the sensitivity of the genetic background of sexual dimorphism on environmental variation. In this study, on Drosophila melanogaster, we used a large nested full-sib–half-sib breeding design where families were split into four different developmental temperatures: two constant temperature treatme…

Adaptation to fluctuations in temperature by nine species of bacteria

Rapid environmental fluctuations are ubiquitous in the wild, yet majority of experimental studies mostly consider effects of slow fluctuations on organism. To test the evolutionary consequences of fast fluctuations, we conducted nine independent experimental evolution experiments with bacteria. Experimental conditions were same for all species, and we allowed them to evolve either in fluctuating temperature alternating rapidly between 20°C and 40°C or at constant 30°C temperature. After experimental evolution, we tested the performance of the clones in both rapid fluctuation and in constant environments (20°C, 30°C and 40°C). Results from experiments on these nine species were combined meta…

Epigenetic control of phenotypic plasticity in a filamentous fungus Neurospora crassa

AbstractPhenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is an ubiquitous feature of living organisms, and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown. In this study, we investigated how e…

Species co-occurrence networks of ground beetles in managed grasslands

AbstractGrassland biodiversity, including traditional rural biotopes maintained by traditional agricultural practices, has become threatened worldwide. Road verges have been suggested to be complementary or compensatory habitats for species inhabiting grasslands. Species co-occurrence patterns linked with species traits can be used to separate between the different mechanisms (stochasticity, environmental filtering, biotic interactions) behind community structure. Here, we study species co-occurrence networks and underlying mechanisms of ground beetle species (Carabidae) in three different managed grassland types (meadows, pastures, road verges, n = 12 in each type) in Central Finland. We a…

Epigenetic Control of Phenotypic Plasticity in the Filamentous Fungus Neurospora crassa

Abstract Phenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is a ubiquitous feature of living organisms, and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown. In this study, we investigated how e…

Inbreeding, energy use and condition

In energetic terms, fitness may be seen to be dependent on successful allocation of energy between life-history traits. In addition, fitness will be constrained by the energy allocation ability, which has also been defined as condition. We suggest here that the allocation ability, estimated as the difference between total energy budget and maintenance metabolism, may be used as a measure of condition. We studied this possibility by measuring the resting metabolic rate and metabolism during forced exercise in Gryllodes sigillatus crickets. To verify that these metabolic traits are closely related to fitness, we experimentally manipulated the degree of inbreeding of individuals belonging to t…

Electronic Supplementary Material from Ecological conditions alter cooperative behaviour and its costs in a chemically defended sawfly.

The evolution of cooperation and social behaviour is often studied in isolation from the ecology of organisms. Yet, the selective environment under which individuals evolve is much more complex in nature, consisting of ecological and abiotic interactions in addition to social ones. Here, we measured the life-history costs of cooperative chemical defence in a gregarious social herbivore, Diprion pini pine sawfly larvae, and how these costs vary under different ecological conditions. We ran a rearing experiment where we manipulated diet (resin content) and attack intensity by repeatedly harassing larvae to produce a chemical defence. We show that forcing individuals to allocate more to cooper…

Roles of adenosine and cytosine methylation changes and genetic mutations in adaptation to different temperatures

Abstract Epigenetic modifications have been found to be involved in evolution, but the relative contributions of genetic and epigenetic variation in adaptation are unknown. Furthermore, previous studies on the role of epigenetic changes in adaptation have nearly exclusively focused on cytosine methylation in eukaryotes. We collected phenotypic, genetic, and epigenetic data from populations of the bacterium Serratia marcescens that had undergone experimental evolution in contrasting temperatures to investigate the relationship between environment, genetics, epigenetic, and phenotypic traits. The genomic distribution of methylated adenosines (m6A) pointed to their role in regulation of gene e…

Additional file 4 of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

The fluorescence peak profiles for the ARISA genotypes analysed with ABI Prism 3130xl Genetic Analyser and the GeneMapper v.5.0 software (Applied Biosystems, Carlsbad, California, USA). For the 83 strains isolated from Finland, we also determined the ARISA (automated ribosomal intergenic spacer analysis) genotypes following the procedure described by Suomalainen et al. [8]. However, the previously published method was modified so that ABI Prism 3130xl Genetic Analyser is used instead of LI-COR 4200 automatic sequencer The analysis revealed that ARISA genotypes associate uniformly with the clusters from the MLSA scheme. Briefly, the PCR reaction mixture (total volume 10 ul) contained 1X Drea…

Additional file 3 of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Neighbor Joining phylogenetic trees based on the individual sequences of six MLST loci (trpB, rpoD, gyrB, dnaK, atpA,and tuf). MEGA v5.2 was used to evaluate the models for nucleotide substitution for each protein-coding locus and to construct the phylogenetic trees for Finnish F. columnare strains. The F. columnare type strain NCIMB 2248T isolated in the USA and two reference strains JIP39/87 and ATCC49512, both isolated in France, were also included in the phylogenetic analysis. The best model indicated by the lowest Bayesian Information Criterion (BIC) value was used to generate the Neighbor-Joining tree based on 1000 replicates. The T92 model was selected for dnaK, tuf, and gyrB, while …

Additional file 2 of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Target genes and primers for the housekeeping genes of F. columnare. The loci used for the MLST/MLSA scheme are shown in bold font. Length refers to the length of the target sequence. * Reference for 16S rDNA primers [52]. (DOCX 20 kb)

Gene expression centroids that link with low intrinsic aerobic exercise capacity and complex disease risk

A strong link exists between low aerobic exercise capacity and complex metabolic diseases. To probe this linkage, we utilized rat models of low and high intrinsic aerobic endurance running capacity that differ also in the risk for metabolic syndrome. We investigated in skeletal muscle gene-phenotype relationships that connect aerobic endurance capacity with metabolic disease risk factors. The study compared 12 high capacity runners (HCRs) and 12 low capacity runners (LCRs) from generation 18 of selection that differed by 615% for maximal treadmill endurance running capacity. On average, LCRs were heavier and had increased blood glucose, insulin, and triglycerides compared with HCRs. HCRs we…

Roles of adenine methylation and genetic mutations in adaptation to different temperatures in Serratia marcescens

AbstractEpigenetic modifications can contribute to adaptation, but the relative contributions of genetic and epigenetic variation are unknown. Previous studies on the role of epigenetic changes in adaptation in eukaryotes have nearly exclusively focused on cytosine methylation (m5C), while prokaryotes exhibit a richer system of methyltransferases targetting adenines (m6A) or cytosines (m4C, m5C). DNA methylation in prokaryotes has many roles, but its potential role in adaptation still needs further investigation. We collected phenotypic, genetic, and epigenetic data using single molecule real-time sequencing of clones of the bacterium Serratia marcescens that had undergone experimental evol…

Luonnon monimuotoisuus ja vihreä elvytys

Suomi on toistaiseksi selvinnyt koronaviruksen (COVID-19) aiheuttamasta kriisistä taloudellisesti verrokkimaita paremmin, mutta työllisyystilanne on silti heikentynyt ympäri maata ja talouden ennustetaan supistuvan noin 4,7 prosenttia vuonna 20201. Negatiivisten talousvaikutusten minimoimiseksi hallitus on suuntaamassa EU:n elpymisvälineestä varoja käytettäväksi toimiin, jotka samanaikaisesti auttavat ratkaisemaan aikamme kahta merkittävää kriisiä: ilmastonmuutosta ja luontokatoa. Kyse on aidosti vakavista kriiseistä. Esimerkiksi Maailman talousfoorumi on listannut luonnon ekosysteemien romahduksen ja ilmastonmuutoksen torjunnan epäonnistumisen sekä vaikutuksiltaan että todennäköisyydeltään…

Keskeiset keinot luontokadon pysäyttämiseksi

Sanna Marinin hallitus on sitoutunut luonnon monimuotoisuuden tilan parantamiseen ja luontokadon pysäyttämiseen. Lupaus on äärimmäisen tärkeä. Luonnon ekosysteemien heikennys uhkaa elintärkeiden eko-systeemipalveluiden tuotantoa sekä ihmisten terveyttä, hyvinvointia ja turvallisuutta. Maailman talousfoorumi on nostanut luontokadon viiden vakavimman ihmiskuntaa uhkaavan riskin joukkoon. Myös Suomen luontotyyppien ja lajiston uhanalaisuustilanne on hälyttävä. Hallituksen kehysriihessä päätetään hallitusohjelman toteuttamisesta ja lunastetaan vuoden 2019 eduskuntavaalien lupaukset luonto- ja ilmastotoimista. Myös EU:n uusi biodiversiteettistrategia velvoittaa Suomea panostamaan luonnonsuojeluu…

Experimental approaches for testing if tolerance curves are useful for predicting fitness in fluctuating environments

Most experimental studies on adaptation to stressful environments are performed under conditions that are rather constant and rarely ecologically relevant. Fluctuations in natural environmental conditions are ubiquitous and include for example variation in intensity and duration of temperature, droughts, parasite loads, and availability of nutrients, predators and competitors. The frequency and amplitude of many of these fluctuations are expected to increase with climate change. Tolerance curves are often used to describe fitness components across environmental gradients. Such curves can be obtained by assessing performance in a range of constant environmental conditions. In this perspectiv…

Endurance in excercise is associated with courtship call rate in decorated cricket, Gryllodes sigillatus

Question: Is sexual signalling (courtship call rate) determined by physiological fitness (energy metabolism at rest), endurance during physically demanding activity, an aspect of immune defence (lytic activity) or body mass? Organism: Pedigree laboratory population of decorated crickets (Gryllodes sigillatus). Methods: Behavioural trial of male courtship call rate and measurements of males’ physiological performance. Covariance analysis exploring the determinants of courtship call rate. Results: We found that endurance was strongly positively associated with the courtship call rate. However, neither the lytic activity nor the resting metabolic rate correlated with courtship call rate. Toget…

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Additional file 2 of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Target genes and primers for the housekeeping genes of F. columnare. The loci used for the MLST/MLSA scheme are shown in bold font. Length refers to the length of the target sequence. * Reference for 16S rDNA primers [52]. (DOCX 20 kb)

Soiden ennallistamisen suoluonto-, vesistö- ja ilmastovaikutukset. Luontopaneelin yhteenveto ja suositukset luontopolitiikan suunnittelun ja päätöksenteon tueksi.

Suomen alkuperäisestä 10,4 miljoonan hehtaarin suoalasta yli puolet on ojitettu metsä- ja maatalouden sekä turvetuotannon tarpeisiin. Etelä-Suomessa ojitus on ollut voimakkainta: keskimäärin noin 75 prosenttia ja monin paikoin vielä suurempi osa soista on ojitettu. Suot ovat Euroopan luontotyypeistä kaikkein uhanalaisin luontotyyppiryhmä ja Suomella on erityisvastuu soiden suojelusta. Kaikkiaan 54 prosenttia Suomen 50 suoluontotyypistä on uhanalaisia ja lisäksi 20 prosenttia on silmällä-pidettäviä. Ensisijaisesti Suomen soilla elävistä lajeista 11 prosenttia eli yhteensä 120 lajia on uhanalaisia. Uhanalaisilla lajeilla ja luontotyypeillä on korkea riski hävitä Suomesta. Mittava ojitus näkyy…

Additional file 5 of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Phylogenetic tree based on the 16Â s rDNA sequence data obtained from the representatives of Finnish F .columnare genotypes (A-H) studied in this study and other F .columnare sequences obtained from the GenBank. The tree was constructed by a UPGMA clustering method with a resampling of 1,000 bootstrap replicates and the Jukes Cantor model. Two strains representative of each ARISA genotype/MLSA cluster studied in this study were used for tree construction (identical sequences removed for clarity of representation). (PDF 191 kb)

Jatkuvapeitteisen metsänkäsittelyn vaikutukset luonnon monimuotoisuuteen, vesistöihin, ilmastoon, virkistyskäyttöön ja metsätuhoriskeihin

Sekä jatkuvapeitteistä että jaksollista metsänkäsittelyä tehdään eri voimakkuuksilla ja erilaisin hakkuutavoin. Ei ole olemassa yksiselitteistä sääntöä, jolla voitaisiin todeta, kuuluuko jokin tietty hakkuutapa jatkuva-peitteiseen vai jaksolliseen käsittelyyn (avohakkuita lukuun ottamatta). Esimerkiksi yläharvennuksia tehdään molemmissa käsittelytavoissa. Kaikkien metsänkäsittelytapojen aiheuttama häiriö on tyypillisesti sitä voimakkaampi, mitä voimakkaampi hakkuu tehdään. Avohakkuut aiheuttavat suurimman haitallisen vaikutuksen sekä luontoon että moniin metsien tarjoamiin ekosysteemipalveluihin. Yhteiskunnan kokonais-edun kannalta jatkuvapeitteisen käsittelyn osuuden lisääminen puuntuotann…

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

of A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates

Systematic Comparison of Epidemic and Non-Epidemic Carbapenem Resistant Klebsiella pneumoniae Strains

Over the past few decades, extensively drug resistant (XDR) resistant Klebsiella pneumoniae has become a notable burden to healthcare all over the world. Especially carbapenemase-producing strains are problematic due to their capability to withstand even last resort antibiotics. Some sequence types (STs) of K. pneumoniae are significantly more prevalent in hospital settings in comparison to other equally resistant strains. This provokes the question whether or not there are phenotypic characteristics that may render certain K. pneumoniae more suitable for epidemic dispersal between patients, hospitals, and different environments. In this study, we selected seven epidemic and non-epidemic ca…

Data from: Intensive aquaculture selects for increased virulence and interference competition in bacteria

Although increased disease severity driven by intensive farming practices is problematic in food production, the role of evolutionary change in disease is not well understood in these environments. Experiments on parasite evolution are traditionally conducted using laboratory models, often unrelated to economically important systems. We compared how the virulence, growth and competitive ability of a globally important fish pathogen, Flavobacterium columnare, change under intensive aquaculture. We characterized bacterial isolates from disease outbreaks at fish farms during 2003-2010, and compared F. columnare populations in inlet water and outlet water of a fish farm during the 2010 outbreak…

Data from: A mechanistic underpinning for sigmoid dose-dependent infection

Theoretical models of environmentally transmitted diseases often assume that transmission is a constant process, which scales linearly with pathogen dose. Here we question the applicability of such an assumption and propose a sigmoidal form for the pathogens infectivity response. In our formulation, this response arises under two assumptions: 1) multiple invasion events are required for a successful pathogen infection and 2) the host invasion state is reversible. The first assumption reduces pathogen infection rates at low pathogen doses, while the second assumption, due to host immune function, leads to a saturating infection rate at high doses. The derived pathogen dose:infection rate -re…

Data from: Fluctuating temperature leads to evolution of thermal generalism and preadaptation to novel environments

Environmental fluctuations can select for generalism, which is also hypothesized to increase organisms’ ability to invade novel environments. Here, we show that across a range of temperatures, opportunistic bacterial pathogen Serratia marcescens that evolved in fluctuating temperature (daily variation between 24°C and 38°C, mean 31°C) outperforms the strains that evolved in constant temperature (31°C). The growth advantage was also evident in novel environments in the presence of parasitic viruses and predatory protozoans, but less clear in the presence of stressful chemicals. Adaptation to fluctuating temperature also led to reduced virulence in Drosophila melanogaster host, which suggests…

Appendix B. Supplementary results: description of stratification and ice cover, environmental variables, elemental composition of Daphnia, and proportion of Daphnia infected with Larssonia obtusa and Pasteuria ramosa during the study period.

Supplementary results: description of stratification and ice cover, environmental variables, elemental composition of Daphnia, and proportion of Daphnia infected with Larssonia obtusa and Pasteuria ramosa during the study period.

Data from: Different food sources elicit fast changes to bacterial virulence

Environmentally transmitted, opportunistic bacterial pathogens have a life cycle that alternates between hosts and environmental reservoirs. Resources are often scarce and fluctuating in the outside-host environment, whereas overcoming the host immune system could allow pathogens to establish a new, resource abundant and stable niche within the host. We tested if shortterm exposure to different outside-host resource types and concentrations affect Serratia marcescens—(bacterium)’s virulence in Galleria mellonella (moth). As expected, virulence was mostly dictated by the bacterial dose, but we also found a clear increase in virulence when the bacterium had inhabited a low (versus high) resou…

Data from: Propagule pressure increase and phylogenetic diversity decrease community’s susceptibility to invasion

Invasions pose a large threat to native species, but the question of why some species are more invasive, and some communities more prone to invasions than others, is far from solved. Using ten different three-species bacterial communities, we tested experimentally if the phylogenetic relationships between an invader and a resident community and propagule pressure affect invasion probability. We found that greater diversity in phylogenetic distances between the resident community members and the invader lowered invasion success, and higher propagule pressure increased invasion success whereas phylogenetic distance had no clear effect. In the later stages of invasion phylogenetic diversity ha…

Appendix A. Description of the study site, sampling procedure, and chemical analysis.

Description of the study site, sampling procedure, and chemical analysis.

Data from: Heat hardening capacity in Drosophila melanogaster is life stage specific and juveniles show the highest plasticity

Variations in stress resistance and adaptive plastic responses during ontogeny have rarely been addressed, despite the possibility that differences between life stages can affect species' range margins and thermal tolerance. Here, we assessed the thermal sensitivity and hardening capacity of Drosophila melanogaster across developmental stages from larval to the adult stage. We observed strong differences between life stages in heat resistance, with adults being most heat resistant followed by puparia, pupae and larvae. The impact of heat hardening (1 h at 35°C) on heat resistance changed during ontogeny, with the highest positive effect of hardening observed in puparia and pupae and the low…

Data from: Ecological conditions alter cooperative behaviour and its costs in a chemically defended sawfly

The evolution of cooperation and social behaviour is often studied in isolation from the ecology of organisms. Yet, the selective environment under which individuals evolve is much more complex in nature, consisting of ecological and abiotic interactions in addition to social ones. Here we measured the life-history costs of cooperative chemical defence in a gregarious social herbivore, Diprion pini pine sawfly larvae, and how these costs vary under different ecological conditions. We ran a rearing experiment where we manipulated diet (resin content) and attack intensity by repeatedly harassing larvae to produce a chemical defence. We show that forcing individuals to allocate more to coopera…

Data from: Effects of acclimation time and epigenetic mechanisms on growth of Neurospora in fluctuating environments

Reaction norms or tolerance curves have often been used to predict how organisms deal with fluctuating environments. A potential drawback is that reaction norms measured in different constant environments may not capture all aspects of organismal responses to fluctuating environments. We examined growth of the filamentous fungus Neurospora crassa in fluctuating temperatures and tested if growth in fluctuating temperatures can be explained simply by growth in different constant temperatures or if more complex models are needed. In addition, as previous studies on fluctuating environments have revealed that past temperatures that organisms have experienced can affect their response to current…

Data from: Broad thermal tolerance is negatively correlated with virulence in an opportunistic bacterial pathogen

Predicting the effects of global increase in temperatures on disease virulence is challenging, especially for environmental opportunistic bacteria, because pathogen fitness may be differentially affected by temperature within and outside host environment. So far, there is very little empirical evidence on the connections between optimal temperature range and virulence in environmentally growing pathogens. Here we explored if the virulence of an environmentally growing opportunistic fish pathogen, Flavobacterium columnare, is malleable to evolutionary changes via correlated selection on thermal tolerance. To this end, we experimentally quantified the thermal performance curves (TPCs) for max…

Supplemental Material for Kronholm et al., 2020

Supplementary material that includes a figure and table for article: Marked Neurospora crassa strains for competition experiments and Bayesian methods for fitness estimates. By Kronholm et al.

Data from: Evolution of bacterial life history traits is sensitive to community structure

Very few studies have experimentally assessed the evolutionary effects of species interactions within the same trophic level. Here we show that when Serratia marcescens evolve in multispecies communities, their growth rate exceeds the growth rate of the bacteria that evolved alone, whereas the biomass yield gets lower. In addition to the community effects per se, we found that few species in the communities caused strong effects on S. marcescens evolution. The results indicate that evolutionary responses (of a focal species) are different in communities, compared to species evolving alone. Moreover, selection can lead to very different outcomes depending on the community structure. Such con…

Original data and analysis scripts for article: Marked Neurospora crassa strains for competition experiments and Bayesian methods for fitness estimates

Research data of an article: "Application of high resolution melting assay (HMR) to study temperature dependent infraspecific competition in an pathogenic bacterium."

Studies on species’ responses to climate change have focused largely on the direct effect of abiotic factors and in particular temperature, neglecting the effects of biotic interactions in determining the outcome of climate change projections. Many microbes rely on strong interference competition; hence the fitness of many pathogenic bacteria could be a function of both their growth properties and intraspecific competition. However, due to technical challenges in distinguishing and tracking individual strains, experimental evidence on intraspecific competition has been limited so far. Here, we developed a robust application of the high-resolution melting (HRM) assay to study head-to-head co…

The effect of environmental fluctuations – Could climate change promote species’ invasion success?

The global climate change is presumed to increase the amount of fluctuations in the environmental conditions. This could increase the amount of species invasion into new areas if fluctuations affect the ecological and evolutionary processes that make species successful as invaders, and native communities and their environments more susceptible to invasions1. Disturbed environments are assumed to be more prone to invasions and the fluctuations in invasive species’ home range could pre-adapt them to tolerate similar conditions elsewhere. Under fluctuating conditions, natural selection could potentially favor traits like generalism, which is profitable in adaptation to wide range of conditions…