Search results for " Development"

2018

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…

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

2016

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…

A self-inducible heterologous protein expression system in Escherichia coli

2016

AbstractEscherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. The inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in E. coli. Isopropyl-β-D-thiogalactoside (IPTG) is currently the most efficient molecular inducer for regulating this promoter’s transcriptional activity. However, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture monitoring. Here, we report the novel SILEX (Self-InducibLe Expression) system, which is a convenient, cost-effective alternative that does not require cell density monitoring or IPTG inducti…

Transient Transformation of A. thaliana Seedlings by Vacuum Infiltration

2020

Transient expression in Arabidopsis thaliana seedlings allows fast expression of fluorescent markers for different subcellular compartments. This protocol describes a transient transformation assay with five-day-old seedlings using Agrobacterium tumefaciens-mediated vacuum infiltration. Three days after infiltration of the Agrobacterium containing an expression vector for a fluorescent marker of interest, cotyledon cells expressing the fluorescent protein can be imaged in a confocal microscope. This assay allows high-throughput screening of new constructs and the study of the localization of a large number of subcellular markers in Arabidopsis seedlings including wild-type, stable over-expr…

First report of neofusicoccum batangarum as causal agent of scabby cankers of cactus pear (Opuntia ficus-indica) in minor islands of sicily

2018

Cactus pear (Opuntia ficus-indica, Cactaceae), native to Mexico, is a multipurpose crop. About 90% of Italian production of cactus pear fruit is from Sicily. In 2013, a disease of cactus pear was noticed in minor islands of Sicily, Lampedusa and Linosa (Pelagie archipelago), Favignana (Aegadian archipelago), and Ustica, where cactus pear is grown as living fences. Symptoms were on flattened stems functioning as leaves (cladodes) and included radially expanding cankers, up to 20 cm in diameter, concentric, crusty, silvery areas, with minute, black dots (pycnidia erumpent from epidermis) and a leathery, brown halo. A milky to buff colored exudate, caking on contact with air, oozed from active…

On the thermodynamic origin of metabolic scaling

2018

The origin and shape of metabolic scaling has been controversial since Kleiber found that basal metabolic rate of animals seemed to vary as a power law of their body mass with exponent 3/4, instead of 2/3, as a surface-to-volume argument predicts. The universality of exponent 3/4 -claimed in terms of the fractal properties of the nutrient network- has recently been challenged according to empirical evidence that observed a wealth of robust exponents deviating from 3/4. Here we present a conceptually simple thermodynamic framework, where the dependence of metabolic rate with body mass emerges from a trade-off between the energy dissipated as heat and the energy efficiently used by the organi…

Standardised spider (Arachnida, Araneae) inventory of Lammi, Finland

2020

In June 2019, an ecology field course of the University of Helsinki was held at Lammi Biological Station, Southern Finland. Within this course, the students familiarised themselves with field work and identification of spiders and explored the diversity of species in the area. Three sampling plots were chosen, one in grassland and two in boreal forest, to demonstrate the sampling techniques and, by applying a standardised protocol (COBRA), contribute to a global spider biodiversity project. The collected samples contained a total of 3445 spiders, of which 1956 (57%) were adult. Only adult spiders were accounted for in the inventory due to the impossibility of identification of juveniles. A …

Metabolic profiling and post-harvest behavior of “dottato” fig (Ficus carica L.) fruit covered with an edible coating from O. ficus-indica

2018

Fig fruits are usually highly sensitive to some physiopathological disorders during post-harvest life, such as softening and skin cracking. Indeed, the use of edible coating (EC) has been evaluated in several fruit crops to reduce fruit post-harvest transpiration and to maintain fruit visual quality. The aim of this study was to determine the post-harvest metabolic response of breba figs treated with mucilage extract from O. ficus-indica cladodes, using an untargeted metabolomic approach. Coated and non coated (control) fruit were sealed in plastic bags, and stored at 4 °C for 7 days. The effect of the edible coatings on their quality fruit during cold storage and qualitative attributes wer…

Changes in freshwater sediment microbial populations during fermentation of crude glycerol

2020

This work was supported by the Latvian Council of Science , project NN-CARMA, project No. lzp-2018/1-0194.

Isolation of acetic, propionic and butyric acid-forming bacteria from biogas plants.

2015

In this study, acetic, propionic and butyric acid-forming bacteria were isolated from thermophilic and mesophilic biogas plants (BGP) located in Germany. The fermenters were fed with maize silage and cattle or swine manure. Furthermore, pressurized laboratory fermenters digesting maize silage were sampled. Enrichment cultures for the isolation of acid-forming bacteria were grown in minimal medium supplemented with one of the following carbon sources: Na(+)-dl-lactate, succinate, ethanol, glycerol, glucose or a mixture of amino acids. These substrates could be converted by the isolates to acetic, propionic or butyric acid. In total, 49 isolates were obtained, which belonged to the phyla Firm…