O gênero Vibrio: conceitos atuais e novas perspectivas

O gênero Vibrio é um grupo bacteriano extremamente versátil. Seus membros são amplamente distribuídos em ambientes aquáticos, sendo a maioria não patogênica. Contudo, algumas espécies são patógenos de humanos e animais, causando impactos significativos na saúde pública e economia. Recentemente, o estudo dessas bactérias vem ganhando mais destaque, constituindo a área central de pesquisas em diversas áreas da Microbiologia. Nesse sentido, estudos buscam investigar sua patogenicidade, perfil de susceptibilidade aos antimicrobianos, potencialidades biotecnológicas e suas interações com fatores ambientais, sendo este último de notável relevância no contexto das mudanças climáticas. Assim, o presente trabalho objetiva fornecer uma revisão atualizada a respeito do gênero Vibrio, evidenciando sua relevância no contexto ambiental e clínico e indicando potenciais áreas para futuros estudos.The genus Vibrio is an extremely versatile bacterial group. Its members are widely distributed in aquatic environments, the majority being harmless. However, some species are known as human and animal pathogens, causing significant impacts on public health and the economy. The study of Vibrio has been gaining more prominence, constituting the central area of research in distinct Microbiology areas. Accordingly, several studies seek to investigate their pathogenicity, antimicrobial susceptibility profile, biotechnological potentialities, as well as their interactions with environmental parameters, the latter being of remarkable importance within the framework of climate change. Thus, this work aims to provide an updated literature review regarding the genus Vibrio, highlighting its medical and environmental relevance, while also indicating potential areas for future studies

Microrganismos marinhos: um reservatório de hidrolases biotecnologicamente interessantes

This review aims to provide an updated narrative review about hydrolytic enzymes (agarases, amylases, cellulases, esterases, lipases, peptidases, and chitinases) isolated from the marine microbiome. These biocatalysts have unique biochemical properties, such as halotolerance, extremes of pH, temperature, and barophilicity, which make them attractive for use in several industrial sectors and stimulating future biotechnological applications. Considering the vast enzymatic repertoire of the various microbial communities living in the marine environment, it is highlighted the importance of harnessing this habitat, specifically these biocatalytic units. Consequently, with proper attention to the industrial perspective, new biocatalysts will be successfully discovered in the marine microbial communities, confirming their practical and valuable activity application to the attractive sectors and generating intellectual property.Esta revisão tem por objetivo fornecer uma revisão narrativa atualizada acerca de enzimas hidrolíticas (agarases, amilases, celulases, esterases, lipases, peptidases e quitinases) isoladas do microbioma marinho. Esses biocatalisadores apresentam propriedades bioquímicas únicas, como halotolerância, extremos de pH, temperatura e barofilicidade, que os tornam atraentes para uso em diversos setores industriais, estimulando futuras aplicações biotecnológicas. Considerando o vasto repertório enzimático dos diversos membros das comunidades microbianas vivendo no ambiente marinho, salienta-se a imprescindibilidade de acessar esse habitat, mais especificamente essas unidades biocatalíticas. Com a devida atenção voltada ao viés industrial, novos biocatalisadores serão descobertos com sucesso nas comunidades microbianas marinhas, desde a confirmação de sua atividade até a comprovação de seu emprego prático nos setores de interesse e geração de propriedade intelectual

AVALIAÇÃO DA ATIVIDADE ANTIBACTERIANA DO VENENO BRUTO DE Crotalus durissus terrificus

Os venenos de serpentes são reconhecidos como uma fonte promissora de substâncias farmacologicamente ativas e potencialmente úteis para o desenvolvimento de novas drogas antimicrobianas. Esse trabalho teve como objetivo investigar a atividade antimicrobiana do veneno de Crotalus durissus terrificus contra várias bactérias. A determinação da atividade antibacteriana foi realizada pelo método de microdiluição em placas e a ação na estrutura do envelope bacteriano pelo ensaio violeta de cristal. As proteínas do extrato bruto foram separadas por eletroforese e caracterizadas quanto à sua atividade proteolítica. O veneno de C. d. terrificus apresentou ação antimicrobiana frente bactérias gram-positivas e gram-negativas. Os valores de MIC foram definidos para Pseudomonas aeruginosa ATCC 27853 (62.5 μg/ mL), Staphylococcus aureus ATCC 25923 (125 μg/mL) e Micrococcus luteus ATCC 9341 (≤ 500 μg/mL). Para Salmonella enterica serovar typhimurium ATCC 14028 e Corynebacterium glutamicum ATCC 13032, o decréscimo no crescimento bacteriano não foi detectado visualmente, mas foi estatisticamente significante. O teste do cristal violeta demonstrou que o veneno bruto aumentou a permeabilidade das células bacterianas e o perfil de proteína secretada está em consonância com relatos anteriores. Os resultados sugerem que as proteínas com atividade lítica contra bactérias no veneno de C. d. terrificus merecem atenção para uma melhor caracterização, uma vez que podem trazer reforços para o escasso arsenal terapêutico empregado para combater a multirresistência microbiana.Palavras-chave: veneno de cascavel, ação antimicrobiana, envelope celular, atividade proteolítica

Identification of BgP, a cutinase-like polyesterase from a deep-sea sponge-derived actinobacterium

Many marine bacteria produce extracellular enzymes that degrade complex molecules to facilitate their growth in environmental conditions that are often harsh and low in nutrients. Marine bacteria, including those inhabiting sea sponges, have previously been reported to be a promising source of polyesterase enzymes, which have received recent attention due to their potential ability to degrade polyethylene terephthalate (PET) plastic. During the screening of 51 marine bacterial isolates for hydrolytic activities targeting ester and polyester substrates, a Brachybacterium ginsengisoli B129SM11 isolate from the deep-sea sponge Pheronema sp. was identified as a polyesterase producer. Sequence analysis of genomic DNA from strain B129SM11, coupled with a genome "mining" strategy, allowed the identification of potential polyesterases, using a custom database of enzymes that had previously been reported to hydrolyze PET or other synthetic polyesters. This resulted in the identification of a putative PET hydrolase gene, encoding a polyesterase-type enzyme which we named BgP that shared high overall similarity with three well-characterized PET hydrolases-LCC, TfCut2, and Cut190, all of which are key enzymes currently under investigation for the biological recycling of PET. In silico protein analyses and homology protein modeling offered structural and functional insights into BgP, and a detailed comparison with Cut190 revealed highly conserved features with implications for both catalysis and substrate binding. Polyesterase activity was confirmed using an agar-based polycaprolactone (PCL) clearing assay, following heterologous expression of BgP in Escherichia coli. This is the first report of a polyesterase being identified from a deep-sea sponge bacterium such as Brachybacterium ginsengisoli and provides further insights into marine-derived polyesterases, an important family of enzymes for PET plastic hydrolysis. Microorganisms living in association with sponges are likely to have increased exposure to plastics and microplastics given the wide-scale contamination of marine ecosystems with these plastics, and thus they may represent a worthwhile source of enzymes for use in new plastic waste management systems. This study adds to the growing knowledge of microbial polyesterases and endorses further exploration of marine host-associated microorganisms as a potentially valuable source of this family of enzymes for PET plastic hydrolysis

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle