Search results for " Biochemistry"
showing 10 items of 5648 documents
Arabidopsis SGS2 and SGS3 genes are required for posttranscriptional gene silencing and natural virus resistance.
2000
AbstractPosttranscriptional gene silencing (PTGS) in plants results from the degradation of mRNAs and shows phenomenological similarities with quelling in fungi and RNAi in animals. Here, we report the isolation of sgs2 and sgs3 Arabidopsis mutants impaired in PTGS. We establish a mechanistic link between PTGS, quelling, and RNAi since the Arabidopsis SGS2 protein is similar to an RNA-dependent RNA polymerase like N. crassa QDE-1, controlling quelling, and C. elegans EGO-1, controlling RNAi. In contrast, SGS3 shows no significant similarity with any known or putative protein, thus defining a specific step of PTGS in plants. Both sgs2 and sgs3 mutants show enhanced susceptibility to virus, d…
Gene flow relates to evolutionary divergence among populations at the range margin
2020
Background Morphological differentiation between populations resulting from local adaptations to environmental conditions is likely to be more pronounced in populations with increasing genetic isolation. In a previous study a positive clinal variation in body size was observed in isolated Roesel’s bush-cricket, Metrioptera roeselii, populations, but were absent from populations within a continuous distribution at the same latitudinal range. This observational study inferred that there was a phenotypic effect of gene flow on climate-induced selection in this species. Methods To disentangle genetic versus environmental drivers of population differences in morphology, we measured the size of …
Quantifying and addressing the prevalence and bias of study designs in the environmental and social sciences
2020
Building trust in science and evidence-based decision-making depends heavily on the credibility of studies and their findings. Researchers employ many different study designs that vary in their risk of bias to evaluate the true effect of interventions or impacts. Here, we empirically quantify, on a large scale, the prevalence of different study designs and the magnitude of bias in their estimates. Randomised designs and controlled observational designs with pre-intervention sampling were used by just 23% of intervention studies in biodiversity conservation, and 36% of intervention studies in social science. We demonstrate, through pairwise within-study comparisons across 49 environmental da…
Ecological dependencies make remote reef fish communities most vulnerable to coral loss
2021
Ecosystems face both local hazards, such as over-exploitation, and global hazards, such as climate change. Since the impact of local hazards attenuates with distance from humans, local extinction risk should decrease with remoteness, making faraway areas safe havens for biodiversity. However, isolation and reduced anthropogenic disturbance may increase ecological specialization in remote communities, and hence their vulnerability to secondary effects of diversity loss propagating through networks of interacting species. We show this to be true for reef fish communities across the globe. An increase in fish-coral dependency with the distance of coral reefs from human settlements, paired with…
Effect of temperature on pollen germination for several Rosaceae species: influence of freezing conservation time on germination patterns
2019
[EN] Between February 2018 and April 2018, flowers were collected from eight Rosaceae species. Flowers were kept in a freezer at -20 degrees C for three freezing times (Treatment 1, two months; Treatment 2, four months; Treatment 3, six months). After extracting pollen, in vitro germination was induced in a culture medium and incubated at six different temperatures for 72 h. The percentage of pollen germination, average pollen tube length and maximum pollen tube length were measured. Pollen germination was maximum for all species between 15 degrees C and 30 degrees C. Cydonia oblonga, Malus sylvestris, Prunus avium, Prunus domestica, Prunus dulcis, Prunus persica and Pyrus communis obtained…
Adaptation in response to environmental unpredictability
2017
Understanding how organisms adaptively respond to environmental fluctuations is a fundamental question in evolutionary biology. The Mediterranean region typically exhibits levels of environmental unpredictability that vary greatly in habitats over small geographical scales. In cyclically parthenogenetic rotifers, clonal proliferation occurs along with occasional bouts of sex. These bouts contribute to the production of diapausing eggs, which allows survival between growing seasons. Here, we studied two diapause-related traits in rotifers using clones from nine Brachionus plicatilis natural populations that vary in the degree of environmental unpredictability. We tested the hypothesis that …
Can video playback provide social information for foraging blue tits?
2017
Video playback is becoming a common method for manipulating social stimuli in experiments. Parid tits are one of the most commonly studied groups of wild birds. However, it is not yet clear if tits respond to video playback or how their behavioural responses should be measured. Behaviours may also differ depending on what they observe demonstrators encountering. Here we present blue tits (Cyanistes caeruleus) videos of demonstrators discovering palatable or aversive prey (injected with bittertasting Bitrex) from coloured feeding cups. First we quantify variation in demonstrators’ responses to the prey items: aversive prey provoked high rates of beak wiping and head shaking. We then show tha…
Reducing the effect of beauvericin on neuroblastoma SH-SY5Y cell line by natural products
2020
Abstract In the present work, different natural compounds from coffee by-product extracts (coffee silverskin and spent coffee) rich in polyphenols, was investigated against beauvericin (BEA) induced-cytotoxicity on SH-SY5Y cells. Spent coffee arise as waste products through the production of instant coffee and coffee brewing; while the silverskin is a tegument which is removed and eliminated with toasting coffee grains. First of all, polyphenol extraction methods, measurement of total polyphenols content and its identification were carried out. Afterwards evaluating in vitro effects with MTT assay on SH-SY5Y cells of coffee by-product extracts and mycotoxins at different concentrations and …
Simultaneous determination of nine phytohormones in seaweed and algae extracts by HPLC-PDA.
2016
An RP-HPLC-PDA method for the simultaneous analysis of 9 compounds deriving from the phytohormones class was developed and optimized, namely indoleacetic acid (IAA), indolebutyric acid (IBA), phenyleacetic acid (PAA), naphtyleacetic acid (NAA), trans-zeatin (TZ), kinetin (KA), isopentenyladenine (IA), 6-benzylaminopurine (6-BA) and abscisic acid (ABA). Validation of the method was performed on the SFE-CO2 extract made out of the mixture of Baltic algae. The regression coefficients for plant hormones were in the range from 0.997 to 0.999. The LOD and LOQ were on the levels from 0.05–0.29 and 0.15–0.88 mg/L, respectively. Developed method was used for the separation and determination plant ho…
Effect of pH on malolactic fermentation in southern Italian wines
2018
This study investigated the influence of pH on malolactic fermentation (MLF) in white wines (adjusted to pH 3.2, 3.4 and 3.8, respectively) from Falanghina grapes and red wines (adjusted to pH 3.4 and 3.8, respectively) from Tintilia grapes. The wines were inoculated with Oenococcus oeni and Lactobacillus plantarum strains, and a mix of them (50:50), in red Tintilia only. The time required to complete MLF in wines from white Falanghina grapes at pH 3.4 and 3.8 was lower with O. oeni, while MLF did not occur at pH 3.2. In red Tintilia, MLF was always completed within 35 days; at high pH (3.8) a significant increase in histamine was detected, while the decrease in citric acid concentration ca…