Search results for "bacteri"

Applying the Anna Karenina principle for wild animal gut microbiota: Temporal stability of the bank vole gut microbiota in a disturbed environment.

2020

Gut microbiota play an important role in host health. Yet, the drivers and patterns of microbiota imbalance (dysbiosis) in wild animals remain largely unexplored. One hypothesised outcome of stress on animal microbiomes is a destabilised microbial community that is characterised by an increase in inter-individual differences compared with microbiomes of healthy animals, which are expected to be (a) temporally stable and (b) relatively similar among individuals. This set of predictions for response of microbiomes to stressors is known as the Anna Karenina principle (AKP) for animal microbiomes. We examine the AKP in a wild mammal inhabiting disturbed environments by conducting a capture-mark…

Biopreservation of tomatoes using fermented media by lactic acid bacteria

2020

Abstract Post-harvest spoilage fungi in tomatoes represent an economic loss for industry and consumers. There is currently an increasing demand for novel applications of bio-preservatives as replacers of chemical additives and pesticides in food. In this study, nine lactic acid bacteria strains isolated from tomato and sourdough were screened for antifungal activity in vitro against 33 fungal strains and used as bio-preservatives of tomato inoculated with Penicillium expansum and Aspergillus flavus. The identification of the compounds potentially responsible for the antifungal activity, such as organic acids, phenolic acids and volatile organic compounds (VOCs), were identified and quantifi…

Evaluation of microbiological and physico‐chemical parameters of retail ready‐to‐eat mono‐varietal salads

2019

An integrated microbiological and physico-chemical approach was applied to evaluate the decay of mono-varietal ready-to-eat escarole (Cichorium endivia var. latifolium) and red chicory (Cichorium intybus L. var. foliosum Hegi) during refrigeration. Total mesophilic microorganisms, including pseudomonads, and total psychrotrophic microorganisms were detected at high numbers in all samples just after packaging and at the expiry date. The dominant microbial populations analyzed by classical culture-dependent methods belonged to Pseudomonas and yeasts. Illumina sequencing identified Janthinobacterium lividum and Pseudomonas veronii as main species. Regarding the physico-chemical quality between…

Infection by Endosymbiotic “Male-Killing” Bacteria in Coleoptera

2018

Wolbachia, Rickettsia, Spiroplasma and Cardinium are endosymbiotic and intracellular bacteria known to cause numerous disorders in host reproduction, reflected in their common name “male-killers”. In this study, 297 beetle species from various taxonomic groups were screened with the use of molecular markers for the presence of infection by any of these endosymbionts. Wolbachia was found to be the most common “male-killer” among beetle hosts as it infected approx. 27% of species. Rickettsia, Spiroplasma and Cardinium were much less prevalent as they infected: 8%, 3% and 2%, respectively, of the studied beetle species. This is the first report of Cardinium presence in beetle hosts. Incidences…

Foreword

2007

Carbon dynamics modelization and biological community sensitivity to temperature in an oligotrophic freshwater Antarctic lake

2016

Lake Limnopolar, located in one of the areas on Earth experiencing the strongest local warming, has been studied as a maritime Antarctic lake model by the Limnopolar Research Team during the last decade. Data collected during this period revealed the existence of an important meteorological interannual variability in the area of Byers Peninsula. With the aim of increasing the knowledge of this ecosystem and its sensibility to climate change as a model ecosystem, as well as to calibrate the extent of the interannual variability, a carbon flow model was developed partly describing its microbial food web. This preliminary model aims to describe part of the carbon dynamics, especially for bacte…

In vitro colonic fermentation of a plant sterol-enriched beverage in a dynamic-colonic gastrointestinal digester

2021

Abstract The impact of a plant sterol-enriched beverage on the sterol metabolism, organic acid production and microbiota composition was evaluated by means of a dynamic gastrointestinal and colonic fermentation model. After one week of fermentation, an absence of sterol metabolites was reported, in accordance with the lack of microbiota related to their metabolism. Although total organic acid content was lower in the ascending colon (AC) compared to the transversal (TC) and descending colon (DC) (28–57 mmol/L vs. 55-87 and 44–64 mmol/L, respectively), its increments, with respect to the initial value, were higher (2-fold vs. 1.6- and 1.5-fold). Increments of acetate, butyrate and propionate…

Antimicrobial secondary metabolites from the medicinal plant Crinum glaucum A. Chev. (Amaryllidaceae)

2020

Abstract Medicinal plants are known as sources of potential antibacterial compounds including alkaloids. The aim of the present study was to evaluate the antibacterial activities of the extract, fractions, and some secondary metabolites isolated from the leaves of Crinum glaucum A. Chev. (Amaryllidaceae). The antibacterial activities were performed with the ethanol (EtOH) extract, as well as with ethyl acetate (EtOAc) and n-butanol (n-BuOH) fractions. Repeated column chromatography of the fractions led to the isolation of several compounds and their structures were elucidated mainly by means of extensive spectroscopic analysis [(one-dimensional (1D) and two-dimensional (2D) nuclear magnetic…

Chromosome numbers for the Italian flora: 11

2021

In this contribution, new chromosome data obtained on material collected in Italy are presented. It includes counts for Centaurea aegusae, Hieracium racemosum subsp. lucanum, H. australe subsp. australe, Lysimachia arvensis subsp. arvensis, Micromeria graeca subsp. graeca, and M. graeca subsp. consentina.

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…