Regenerated forests now compose over half of the world's tropical forest cover and are increasingly important as providers of ecosystem services, freshwater, and biodiversity conservation. Much of ...the value and functionality of regenerating forests depends on the plant diversity they contain. Tropical forest diversity is strongly shaped by mutualistic interactions between plants and fruit-eating animals (frugivores) that disperse seeds. Here we show how seed dispersal by birds can influence the speed and diversity of early successional forests in Puerto Rico. For two years, we monitored the monthly fruit production of bird-dispersed plants on a fragmented landscape, and measured seed dispersal activity of birds and plant establishment in experimental plots located in deforested areas. Two predominantly omnivorous bird species, the Northern Mockingbird (Mimus polyglottes) and the Gray Kingbird (Tyrannus dominicensis), proved critical for speeding up the establishment of woody plants and increasing the species richness and diversity of the seed rain in deforested areas. Seed dispersal by these generalists increased the odds for rare plant species to disperse and establish in experimental forest-regeneration plots. Results indicate that birds that mix fruit and insects in their diets and actively forage across open and forested habitats can play keystone roles in the regeneration of mutualistic plant-animal communities. Furthermore, our analyses reveal that rare-biased (antiapostatic) frugivory and seed dispersal is the mechanism responsible for increasing plant diversity in the early-regenerating community.
The chloride anion as a signalling effector Valdivieso, Ángel G.; Santa‐Coloma, Tomás A.
Biological Reviews,
October 2019, 2019-10-00, 20191001, Letnik:
94, Številka:
5
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
The specific role of the chloride anion (Cl−) as a signalling effector or second messenger has been increasingly recognized in recent years. It could represent a key factor in the regulation ...of cellular homeostasis. Changes in intracellular Cl− concentration affect diverse cellular functions such as gene and protein expression and activities, post‐translational modifications of proteins, cellular volume, cell cycle, cell proliferation and differentiation, membrane potential, reactive oxygen species levels, and intracellular/extracellular pH. Cl− also modulates functions in different organelles, including endosomes, phagosomes, lysosomes, endoplasmic reticulum, and mitochondria. A better knowledge of Cl− signalling could help in understanding the molecular and metabolic changes seen in pathologies with altered Cl− transport or under physiological conditions. Here we review relevant evidence supporting the role of Cl− as a signalling effector.
The catalytic oxidation of p-xylene is investigated, focusing on the chemistry and kinetics responsible for it. Another focus is the industrial processing of terephthalic acid and an overview of ...hydrocarbon oxidation.
Dietary phenolic compounds are often transformed before absorption. This transformation modulates their biological activity. Different studies have been carried out to understand gut microbiota ...transformations of particular polyphenol types and identify the responsible microorganisms. Although there are potentially thousands of different phenolic compounds in the diet, they are typically transformed to a much smaller number of metabolites. The aim of this review was to discuss the current information about the microbial degradation metabolites obtained from different phenolics and their formation pathways, identifying their differences and similarities. The modulation of gut microbial population by phenolics was also reviewed in order to understand the two-way phenolic−microbiota interaction. Clostridium and Eubacterium genera, which are phylogenetically associated, are other common elements involved in the metabolism of many phenolics. The health benefits from phenolic consumption should be attributed to their bioactive metabolites and also to the modulation of the intestinal bacterial population.
Urolithins are dibenzob,dpyran‐6‐one derivatives that are produced by the human gut microbiota from ellagitannins and ellagic acid (EA). These metabolites are much better absorbed than their ...precursors and have been suggested to be responsible for the health effects attributed to ellagitannins and EA that occur in food products as berries and nuts. In the present review, the role and potential of urolithins in human health are critically reviewed, and a perspective of the research approach needed to demonstrate these health effects is presented, based on the existing knowledge. The analytical methods available for urolithin analysis, their occurrence in different tissues and biological fluids, and their metabolism by human gut microbiota are considered. In addition, the interindividual variability observed for the production of urolithins (metabotypes) and its relationship with health status and dysbiosis are also reviewed. The potential mechanisms of action of urolithins are also critically discussed, paying attention to the concentration and the type of metabolites used in the in vitro and in vivo assays and the physiological significance of the results obtained. The gut microbiota metabolism of EA to urolithins and that of daidzein to equol, their individual variations, and the effects on health are also compared.
The role of urolithins in human health after the consumption of dietary ellagitannins (ETs) is reviewed. The review shows preclinical evidence and in vitro mechanistic studies indicating that ETs can have anti‐inflammatory effects. However, no clinical studies have confirmed this effect yet. The recent finding that urolithins can reach the brain has increased the relevance of preclinical studies indicating that urolithins might have a role in protecting against neurodegenerative diseases.
Three phenotypes for urolithin production after ellagitannin and ellagic acid intake are consistently observed in different human intervention trials. Subjects can be stratified into three ...urolithin-producing groups. “Phenotype A” produced only urolithin A conjugates, which included between 25 and 80% of the volunteers in the different trials. “Phenotype B” produced isourolithin A and/or urolithin B in addition to urolithin A, this being the second relevant group (10–50%). “Phenotype 0” (5–25%) was that in which these urolithins were not detected. The three phenotypes were observed independently of the volunteers’ health status and demographic characteristics (age, gender, body mass index (BMI)) and of the amount or type of ellagitannin food source ingested (walnuts and other nuts, strawberries, raspberries, and other berries or pomegranates). Interestingly, a higher percentage of phenotype B was observed in those volunteers with chronic illness (metabolic syndrome or colorectal cancer) associated with gut microbial imbalance (dysbiosis). These urolithin phenotypes could show differences in the human gut microbiota and should be considered in intervention trials dealing with health benefits of ellagitannins or ellagic acid. Whether this phenotypic variation could be a biomarker related to differential health benefits or illness predisposition deserves further research.
Urolithins, metabolites produced by the gut microbiota from the polyphenols ellagitannins and ellagic acid, are discovered by the research group in humans almost 20 years ago. Pioneering research ...suggests urolithins as pleiotropic bioactive contributors to explain the health benefits after consuming ellagitannin‐rich sources (pomegranates, walnuts, strawberries, etc.). Here, this study comprehensively updates the knowledge on urolithins, emphasizing the review of the literature published during the last 5 years. To date, 13 urolithins and their corresponding conjugated metabolites (glucuronides, sulfates, etc.) have been described and, depending on the urolithin, detected in different human fluids and tissues (urine, blood, feces, breastmilk, prostate, colon, and breast tissues). There has been a substantial advance in the research on microorganisms involved in urolithin production, along with the compositional and functional characterization of the gut microbiota associated with urolithins metabolism that gives rise to the so‐called urolithin metabotypes (UM‐A, UM‐B, and UM‐0), relevant in human health. The design of in vitro studies using physiologically relevant assay conditions (molecular forms and concentrations) is still a pending subject, making some reported urolithin activities questionable. In contrast, remarkable progress has been made in the research on the safety, bioactivity, and associated mechanisms of urolithin A, including the first human interventions.
About 20 years ago, urolithins are discovered as bioavailable metabolites produced by the human gut microbiota from ellagitannins and ellagic acid. Pioneering investigations suggested pleiotropic effects for urolithins that growing evidence confirms, especially for urolithin A. Here, we update the knowledge on urolithins metabolism, bioactivity, and associated gut microbiota, emphasizing the literature published in the last 5 years.
Recent studies have demonstrated the impact of diet on microbiota composition, but the essential need for the optimization of production rates and costs forces farms and aquaculture production to ...carry out continuous dietary tests. In order to understand the effect of total fishmeal replacement by vegetable-based feed in the sea bream (Sparus aurata), the microbial composition of the stomach, foregut, midgut and hindgut was analysed using high-throughput 16S rDNA sequencing, also considering parameters of growth, survival and nutrient utilisation indices.A total of 91,539 16S rRNA filtered-sequences were analysed, with an average number of 3661.56 taxonomically assigned, high-quality sequences per sample. The dominant phyla throughout the whole gastrointestinal tract were Actinobacteria, Protebacteria and Firmicutes. A lower diversity in the stomach in comparison to the other intestinal sections was observed. The microbial composition of the Recirculating Aquaculture System was totally different to that of the sea bream gastrointestinal tract. Total fishmeal replacement had an important impact on microbial profiles but not on diversity. Streptococcus (p-value: 0.043) and Photobacterium (p-value: 0.025) were highly represented in fish fed with fishmeal and vegetable-meal diets, respectively. In the stomach samples with the vegetable diet, reads of chloroplasts and mitochondria from vegetable dietary ingredients were rather abundant. Principal Coordinate Analysis showed a clear differentiation between diets in the microbiota present in the gut, supporting the presence of specific bacterial consortia associated with the diet.Although differences in growth and nutritive parameters were not observed, a negative effect of the vegetable diet on the survival rate was determined. Further studies are required to shed more light on the relationship between the immune system and sea bream gastrointestinal tract microbiota and should consider the modulation of the microbiota to improve the survival rate and nutritive efficacy when using plant-based diets.
Ecology Letters (2012)
Several network properties have been identified as determinants of the stability and complexity of mutualistic networks. However, it is unclear which mechanisms give rise to ...these network properties. Phenology seems important, because it shapes the topology of mutualistic networks, but its effects on the dynamics of mutualistic networks have scarcely been studied. Here, we study these effects with a general dynamical model of mutualistic and competitive interactions where the interaction strength depends on the temporal overlap between species resulting from their phenologies. We find a negative complexity–stability relationship, where phenologies maximising mutualistic interactions and minimising intraguild competitive interactions generate speciose, nested and poorly connected networks with moderate asymmetry and low resilience. Moreover, lengthening the season increases diversity and resilience. This highlights the fragility of real mutualistic communities with short seasons (e.g. Arctic environments) to drastic environmental changes.
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