Search results for "Disc"

An eco-physiological and biotechnological approach to conservation of the world-wide rare and endangered aquatic liverwort Riella helicophylla (Bory …

2016

AbstractThe rare aquatic liverwortRiella helicophylla(Bory et Mont.) Mont., inhabitant of temporary shallow ponds around the Mediterranean basin, is considered threatened throughout its distribution range. In addition, little is known of its biology and ecology or of its role in such an important ecosystem where environmental conditions vary yearly in unpredictable ways. In these variable habitats, due to the seasonal fluctuation of water levels, there is no guarantee of yearly spore input into the spore bank. Spore germination rate and the effects of different culture media in an axenic culture establishment, as well as propagation procedures ofR. helicophylla,were tested. New insights int…

2021

Centaurothamnus maximus (family Asteraceae), is a leafy shrub indigenous to the southwestern Arabian Peninsula. With a paucity of phytochemical data on this species, we set out to chemically characterize the plant. From the aerial parts, two newly identified guaianolides were isolated: 3β-hydroxy-4α(acetoxy)-4β(hydroxymethyl)-8α-(4-hydroxy methacrylate)-1αH,5αH, 6αH-gual-10(14),11(13)-dien-6,12-olide (1) and 15-descarboxy picrolide A (2). Seven previously reported compounds were also isolated: 3β, 4α, 8α-trihydroxy-4-(hydroxymethyl)-lαH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6,12-olide (3), chlorohyssopifolin B (4), cynaropikrin (5), hydroxyjanerin (6), chlorojanerin (7), isorhamnetin (8), …

2019

Reptiles use pterin and carotenoid pigments to produce yellow, orange, and red colors. These conspicuous colors serve a diversity of signaling functions, but their molecular basis remains unresolved. Here, we show that the genomes of sympatric color morphs of the European common wall lizard ( Podarcis muralis ), which differ in orange and yellow pigmentation and in their ecology and behavior, are virtually undifferentiated. Genetic differences are restricted to two small regulatory regions near genes associated with pterin [ sepiapterin reductase ( SPR )] and carotenoid [ beta-carotene oxygenase 2 ( BCO2 )] metabolism, demonstrating that a core gene in the housekeeping pathway of pterin bi…

Isolation of a novel linalool disaccharide glycoside from Raspberry fruit

1991

Abstract A new linalool disaccharide glycoside ( 1a ) was isolated from raspberry fruit ( Rubus idaeus , cv. Heritage) and characterized as S-(+)-linalool 3-O-α-L-arabinopyranosyl-(1→6)-β-D-glucopyranoside by means of spectroscopic studies.

Climate determinants of breeding and wintering ranges of lesser kestrels in Italy and predicted impacts of climate change

2017

Climate warming would theoretically create conditions for the breeding range expansion of pseudo-steppe Mediterranean and long-distance migrant species and provide the possibility for these to overwinter in the same breeding areas. However, contemporary changes in rainfall regimes might have negative effects on the climate suitability and in turn, shrink species potential range. The lesser kestrel Falco naumanni is highly sensitive to rainfall oscillations and has recently extended its Italian breeding range towards northern latitudes and increasing its wintering records. We modelled the effects of temperature and rainfall on current and future climate suitability for lesser kestrels in bot…

Cost-efficient strategies to preserve dead wood-dependent species in a managed forest landscape

2016

Negative consequences of intensive forest management on biodiversity are often mitigated by setting aside old forest, but alternative strategies have been suggested. We have compared using simulations the consequences of two of these alternatives setting aside young forests or extending rotation periods - to that of current practice in managed boreal forest In all scenarios we applied a constant conservation budget and predicted forest development and harvesting over 200 years. As a proxy for biodiversity conservation, we projected the extinction risk of a dead wood-dependent beetle, Diacanthous undulatus, in a 50 km(2) landscape in central Sweden, using a colonization-extinction model. Dur…

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

2013

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…

Macrophytes shape trophic niche variation among generalist fishes.

2017

Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation…

Population dynamic consequences of delayed life-history effects

2002

Evidence from wildlife and human populations indicates that conditions during early development can have marked effects on the subsequent performance of individuals and cohorts. Likewise, the effects of maternal and, more generally, parental environments can be transferred among individuals between generations. These delayed life-history effects are found consistently and suggestions have been made that they can be one source of both variability and of delayed density dependence in population dynamics. Assessments of several different time series indicate that population variability and delayed density dependence are common and that understanding the mechanisms giving rise to them is crucia…

Palaeopathological Evidence of Infectious Disease in a Skeletal Population from Late Medieval Riga, Latvia (15Th-17Th Centuries AD)

2017

Abstract The aim of this study was to evaluate the presence of infectious disease in the Dome Church (Riga Cathedral) Cemetery population, dating from the late medieval period (15th-17th centuries AD). A total of 274 individuals were macroscopically observed for evidence of infectious disease, and seven individuals with lesions possibly associated with a bacterial infection affecting the skeleton were selected for further analysis. Pathological changes on the outer table of the skull and in the long bones of legs characteristic of venereal syphilis were observed in four female and one male individual. Likewise, changes possibly related to late congenital syphilis were observed in a 14-15-ye…