Impact of Different Trace Elements on the Growth and Proteome of Two Strains of Granulicella, Class "Acidobacteriia".

Acidobacteria represents one of the most dominant bacterial groups across diverse ecosystems. However, insight into their ecology and physiology has been hampered by difficulties in cultivating members of this phylum. Previous cultivation efforts have suggested an important role of trace elements for the proliferation of Acidobacteria, however, the impact of these metals on their growth and metabolism is not known. In order to gain insight into this relationship, we evaluated the effect of trace element solution SL10 on the growth of two strains (5B5 and WH15) of Acidobacteria belonging to the genus Granulicella and studied the proteomic responses to manganese (Mn). Granulicella species had highest growth with the addition of Mn, as well as higher tolerance to this metal compared to seven other metal salts. Variations in tolerance to metal salt concentrations suggests that Granulicella sp. strains possess different mechanisms to deal with metal ion homeostasis and stress. Furthermore, Granulicella sp. 5B5 might be more adapted to survive in an environment with higher concentration of several metal ions when compared to Granulicella sp. WH15. The proteomic profiles of both strains indicated that Mn was more important in enhancing enzymatic activity than to protein expression regulation. In the genomic analyses, we did not find the most common transcriptional regulation of Mn homeostasis, but we found candidate transporters that could be potentially involved in Mn homeostasis for Granulicella species. The presence of such transporters might be involved in tolerance to higher Mn concentrations, improving the adaptability of bacteria to metal enriched environments, such as the decaying wood-rich Mn environment from which these two Granulicella strains were isolated.

Biocides Used as Additives to Biodiesels and Their Risks to the Environment and Public Health: A Review.

One of the advantages of using biodiesel and its blends with diesel oil is the lower levels of emissions of particulate matter, sulfur dioxide, carbon monoxide, among others, making it less harmful to the environment and to humans. However, this biofuel is susceptible to microbial contamination and biodeterioration. In this sense, studies on the use of effective low toxicity biocides are being carried out, and this work aims to present the latest information (2008⁻2018) available in the scientific databases, on the use of biocides in biodiesel, mainly concerning their toxicity to the environment and public health. The results showed that in relation to the control of microbial contamination, the current scenario is limited, with seven publications, in which the most studied additives were isothiazolinones, oxazolidines, thiocyanates, morpholines, oxaborinanes, thiocarbamates and phenolic antioxidants. Studies regarding direct experiments with humans have not been found, showing the need for more studies in this area, since the potential growth of biodiesel production and consumption in the world is evident. Thus, there are need for more studies on antimicrobial products for use in biodiesel, with good broad-spectrum activity (bactericidal and fungicidal), and further toxicological tests to ensure no or little impact on the environment.

The Ecology of Acidobacteria: Moving beyond Genes and Genomes.

The phylum Acidobacteria is one of the most widespread and abundant on the planet, yet remarkably our knowledge of the role of these diverse organisms in the functioning of terrestrial ecosystems remains surprisingly rudimentary. This blatant knowledge gap stems to a large degree from the difficulties associated with the cultivation of these bacteria by classical means. Given the phylogenetic breadth of the Acidobacteria, which is similar to the metabolically diverse Proteobacteria, it is clear that detailed and functional descriptions of acidobacterial assemblages are necessary. Fortunately, recent advances are providing a glimpse into the ecology of members of the phylum Acidobacteria. These include novel cultivation and enrichment strategies, genomic characterization and analyses of metagenomic DNA from environmental samples. Here, we couple the data from these complementary approaches for a better understanding of their role in the environment, thereby providing some initial insights into the ecology of this important phylum. All cultured acidobacterial type species are heterotrophic, and members of subdivisions 1, 3, and 4 appear to be more versatile in carbohydrate utilization. Genomic and metagenomic data predict a number of ecologically relevant capabilities for some acidobacteria, including the ability to: use of nitrite as N source, respond to soil macro-, micro nutrients and soil acidity, express multiple active transporters, degrade gellan gum and produce exopolysaccharide (EPS). Although these predicted properties allude to a competitive life style in soil, only very few of these prediction shave been confirmed via physiological studies. The increased availability of genomic and physiological information, coupled to distribution data in field surveys and experiments, should direct future progress in unraveling the ecology of this important but still enigmatic phylum.

Soil Acidobacterial 16S rRNA Gene Sequences Reveal Subgroup Level Differences between Savanna-Like Cerrado and Atlantic Forest Brazilian Biomes.

16S rRNA sequences from the phylum Acidobacteria have been commonly reported from soil microbial communities, including those from the Brazilian Savanna (Cerrado) and the Atlantic Forest biomes, two biomes that present contrasting characteristics of soil and vegetation. Using 16S rRNA sequences, the present work aimed to study acidobacterial diversity and distribution in soils of Cerrado savanna and two Atlantic forest sites. PCA and phylogenetic reconstruction showed that the acidobacterial communities found in "Mata de galeria" forest soil samples from the Cerrado biome have a tendency to separate from the other Cerrado vegetation microbial communities in the direction of those found in the Atlantic Forest, which is correlated with a high abundance of Acidobacteria subgroup 2 (GP2). Environmental conditions seem to promote a negative correlation between GP2 and subgroup 1 (GP1) abundance. Also GP2 is negatively correlated to pH, but positively correlated to high Al(3+) concentrations. The Cerrado soil showed the lowest Acidobacteria richness and diversity indexes of OTUs at the species and subgroups levels when compared to Atlantic Forest soils. These results suggest specificity of acidobacterial subgroups to soils of different biomes and are a starting point to understand their ecological roles, a topic that needs to be further explored.

Bacteria and Archaea community structure in the rumen microbiome of goats (Capra hircus) from the semiarid region of Brazil.

Most studies present in the literature about the rumen microbiome have focused on cattle and sheep. This is the first report of the characterization of the bacterial and archaeal communities present in the liquid and solid-associated fractions of the rumen from free ranging Moxotó breed goats using 16S rRNA gene libraries. PCR was used to amplify the 16S rRNA gene with bacterial and archaeal universal primers and sequences from each library constructed were obtained. Sequences of Bacteria from the phyla Bacteroidetes and Firmicutes were predominant. The overall dominant classes in the rumen were Clostridia and Bacteroidia, which are known to play a role in plant fiber degradation in other ruminants. Unclassified Bacteria accounted for 4.7% of the liquid fraction sequences and 16.4% of the solid fraction sequences. From the archaeal libraries only sequences from the phylum Euryarcheota were identified and were assigned to the class Methanobacteria of the genera Methanobrevibacter and Methanosphaera. A group of Archaea not previously known to be associated with the rumen was identified: uncultured methanogens belonging to the "uncultured marine bacteria" groups II and III. The local water contained high salt concentrations and this may explain the presence of these groups in the Moxotó goat rumen.

The effect of low salinity on teredinids

Teredinids survival in low salinities was determined in aquaria. Panels previously immersed in Ponta de Leste, Ilha Grande Bay, Rio de Janeiro, were transferred to aquaria with salinities ranging from 5.0 to 15.0 Practical Salinity Unities (PSU). The waters of Ilha Grande Bay receive a large amount of wood from the marginal rainforest vegetation, being suitable for the development of teredinids. The coastal areas of the bay are subjected to wide salinity fluctuations due to strong and sudden tropical storms. Eleven different species of teredinids were found in the panels. The critical salinity concentration for the survival of the two most common species was 11.93 PSU for Lyrodus floridanus and 12.90 PSU for Teredo furcifera. The effect of time on the mortality of teredinids at low salinities is also discussed.

A sobrevivência de moluscos bivalves perfurantes de madeira da família Teredinidae foi avaliada a partir de sua manutenção em aquários de baixa salinidade. Painéis de madeira previamente imersos em Ponta de Leste, Baía da Ilha Grande, RJ, foram transferidos para aquários, contendo água do mar, cujas concentrações salinas variaram de 5,0 a 15,0 PSU. A Baía da Ilha Grande recebe uma grande quantidade de madeira da vegetação marginal de Mata Atlântica, o que torna o ambiente particularmente favorável ao desenvolvimento de teredinídeos. As áreas costeiras da baía estão sujeitas a grandes variações salinas decorrentes de tempestades tropicais que ocorrem súbita e intensamente. A salinidade crítica à sobrevivência das duas espécies mais comuns nos painéis foi de 11,93, para Lyrodus floridanus e 12,90 para Teredo furcifera. O efeito do tempo na mortalidade dos teredinídeos, quando sujeitos a baixas salinidades, foi discutido.