Biology subjects

Mendez, V.

Publications and source records attributed to Mendez, V..

3 recordsLinked to original sources

bioRxiv2023

Highly pathogenic avian influenza H5N1 virus infections in pinnipeds and seabirds in Uruguay: a paradigm shift to virus transmission in South America

The highly pathogenic avian influenza viruses of the clade 2.3.4.4b have caused unprecedented deaths in South American wild birds, poultry, and marine mammals. In September 2023, pinnipeds and seabirds appeared dead on the Uruguayan Atlantic coast. Sixteen influenza virus strains were characterized by real-time reverse transcription PCR and genome sequencing in samples from sea lions (Otaria flavescens), fur seals (Arctocephalus australis), and terns (Sterna hirundinacea). Phylogenetic and ancestral reconstruction analysis showed that these strains have pinnipeds as the most likely ancestral host, representing a recent introduction of the clade 2.3.4.4b in Uruguay. The Uruguayan and closely related strains from Peru (sea lions) and Chile (sea lions and a human case) carry mammalian adaptative residues 591K and 701N in the viral polymerase basic protein 2 (PB2). Our findings suggest that the clade 2.3.4.4b strains in South America may have spread from mammals to mammals and seabirds, revealing a new transmission route.

microbiology↗

bioRxiv2020

Random searchers cope with cognitive errors and uncertainty better than path planners

There is a widespread belief in ecology that the capacity of animals to orchestrate systematic and planned paths should represent a significant benefit for efficient search and exploration. Within this view, stochasticity observed in real animal trajectories is mostly understood as undesirable noise caused by internal or external effects. Far less is known, however, about the case when cognitive errors and limitations inherent to living systems are explicitly put into play. Here we compare within this context the search efficiency of (i) walkers driven by Bayesian rules generating deterministic paths, (ii) standard random walkers, and (iii) human trajectories obtained from search experiments in a soccer field and on the computer screen. Our results clearly challenge the view that deterministic paths are generally better for exploration than random strategies, as the latter are more resilient to cognitive errors. Instead, we provide numerical and experimental evidence that stochasticity would provide living organisms with a sufficient and cognitively simple exploration solution to the problem of uncertainty.

ecology↗

bioRxiv2017

Degradation of benzene by the heavy-metal resistant bacterium Cupriavidus metallidurans CH34 reveals its catabolic potential for aromatic compounds

Benzene, toluene, ethylbenzene and the three xylene isomers are monoaromatic contaminants widely distributed on polluted sites. Some microorganisms have developed mechanisms to degrade these compounds, but their aerobic and anaerobic degradation is inhibited in presence of heavy metals, such as mercury or lead. In this report, the degradation of benzene and other aromatic compounds catalyzed by the metal resistant bacterium Cupriavidus metallidurans CH34 was characterized. A metabolic reconstruction of aromatic catabolic pathways was performed based on bioinformatics analyses. Functionality of the predicted pathways was confirmed by growing strain CH34 on benzene, toluene, o-xylene, p-cymene, 3-hydroxybenzoate, 4-hydroxybenzoate, 3-hydroxyphenylacetate, 4-hydroxyphenylacetate, homogentisate, catechol, naphthalene, and 2-aminophenol as sole carbon and energy sources. Benzene catabolic pathway was further characterized. Results showed that firstly benzene is transformed into phenol and, thereafter, into catechol. Benzene is degraded under aerobic conditions via a combined pathway catalyzed by three Bacterial Multicomponent Monooxygenases: a toluene-2-monoxygenase (TomA012345), a toluene-4-monooxygenase (TmoABCDEF) and a phenol-2-hydroxylase (PhyZABCDE). A catechol-2,3-dioxygenase (TomB) expressed at early exponential phase cleaves the catechol ring in meta-position; an ortho-cleavage of catechol is accomplished by a catechol-1,2-dioxygenase (CatA) at late exponential phase instead. This study additionally shows that C. metallidurans CH34 is capable of degrading benzene in presence of heavy metals, such as Hg(II) or Pb(II). This capability of degrading aromatic compounds in presence of heavy metals is rather unusual among environmental bacteria; therefore, C. metallidurans CH34 seems to be a promising candidate for developing novel bioremediation process for multi-contaminated environments.\n\nHIGHLIGHTSO_LIThe strain Cupriavidus metallidurans CH34 is capable to degrade benzene aerobically\nC_LIO_LIBenzene oxydation is mediated by bacterial multicomponent monoxygenases\nC_LIO_LIStrain CH34 is able to grow using a broad range of aromatic compounds as sole carbon and energy source\nC_LIO_LIBenzene degradation occurs even in presence of heavy metals such as mercury and lead\nC_LI

microbiology↗