Molecular and Genomic Characterization of PFAB2: A Non-virulent Bacillus anthracis Strain Isolated from an Indian Hot Spring.

BACKGROUND: Thermophilic bacilli in both aerobic or facultative anaerobic forms have been isolated for over a hundred years from different mesophilic or thermophilic environments as they are potential source of bioactive secondary metabolites. But the taxonomic resolution in the Bacillus genus at species or at strain level is very challenging for the insufficient divergence of the 16S rRNA genes. One such recurring problem is among Bacillus anthracis, B. cereus and B. thuringiensis. The disease-causing B. anthracis strains have their characteristic virulence factors coded in two well-known plasmids, namely pXO1 (toxin genes) and pXO2 (capsule genes). OBJECTIVE: The present study aimed at the molecular and genomic characterization of a recently reported thermophilic and environmental isolate of B. anthracis, strain PFAB2. METHODS: We performed comparative genomics between the PFAB2 genome and different strains of B. anthracis, along with closely related B. cereus strains. RESULTS: The pangenomic analysis suggests that the PFAB2 genome harbors no complete prophage genes. Cluster analysis of Bray-Kurtis similarity resemblance matrix revealed that gene content of PFAB2 is more closely related to other environmental strains of B. anthracis. The secretome analysis and the in vitro and in vivo pathogenesis experiments corroborate the avirulent phenotype of this strain. The most probable explanation for this phenotype is the apparent absence of plasmids harboring genes for capsule biosynthesis and toxins secretion in the draft genome. Additional features of PFAB2 are good spore-forming and germinating capabilities and rapid replication ability. CONCLUSION: The high replication rate in a wide range of temperatures and culture media, the non-pathogenicity, the good spore forming capability and its genomic similarity to the Ames strain together make PFAB2 an interesting model strain for the study of the pathogenic evolution of B. anthracis.

Exploring the mycobiota of bromeliads phytotelmata in Brazilian Campos Rupestres.

The phytotelmata is a water-filled tank on a terrestrial plant, and it plays an important role in bromeliad growth and ecosystem functioning. Even though previous studies have contributed to elucidate the composition of the prokaryotic component of this aquatic ecosystem, its mycobiota (fungal community) is still poorly known. In the present work, ITS2 amplicon deep sequencing was used to examine the fungal communities inhabiting the phytotelmata of two bromeliads species that coexist in a sun-exposed rupestrian field of Southeastern Brazil, namely Aechmea nudicaulis (AN) and Vriesea minarum (VM). Ascomycota was the most abundant phylum in both bromeliads (57.1 and 89.1% in AN and VM respectively, on average), while the others were present in low abundance (< 2%). Mortierellomycota and Glomeromycota were exclusively observed in AN. Beta-diversity analysis showed that samples from each bromeliad significantly clustered together. In conclusion, despite the considerable within-group variation, the results suggested that each bromeliad harbor a distinct fungi community, what could be associated with the physicochemical characteristics of the phytotelmata (mainly total nitrogen, total organic carbon, and total carbon) and plant morphological features.

Antimicrobial Properties of Chilean Native Plants: Future Aspects in Their Application in the Food Industry.

Food contamination with microorganisms is responsible for food spoilage, deterioration and change of organoleptic properties of foods. Besides, the growth of pathogenic microorganisms can provoke serious health problems if food is consumed. Innovative packaging, such as active packaging, is increasing rapidly in the food industry, especially in applying antimicrobials into delivery systems, such as sachets. Chile is a relevant hotspot for biodiversity conservation and a source of unique bio-resources with antimicrobial potential. In this review, fifteen native plants with antimicrobial properties are described. Their antimicrobial effects include an effect against human pathogens. Considering the emergence of antimicrobial resistance, searching for new antimicrobials to design new strategies for food pathogen control is necessary. Chilean flora is a promising source of antimicrobials to be used in active packaging. However, further studies are required to advance from laboratory tests of their antimicrobial effects to their possible effects and uses in active films.

Characterization of microbial communities from gut microbiota of hypercholesterolemic and control subjects.

Introduction: In recent years, several studies have evidenced the importance of the microbiome to host physiology as metabolism regulator, along with its potential role in triggering various diseases. In this study, we analyzed the gut microbiota in hypercholesterolemic (cases) and normocholesterolemic (controls) individuals to identify characteristic microbial signature for each condition. Methods: Stool samples were obtained from 57 adult volunteers (27 hypercholesterolemic and 30 controls). The taxonomic profiling of microbial communities was performed using high-throughput sequencing of 16S rRNA V3-V4 amplicons, followed by data analysis using Quantitative Insights Into Microbial Ecology 2 (QIIME2) and linear discriminant analysis (LDA) effect size (LEfSe). Results: Significant differences were observed in weight, height, body mass index (BMI) and serum levels of triglycerides, total cholesterol and low-density lipoprotein cholesterol (LDL-C) between the groups (p<0.05). LEfSe showed differentially abundant prokaryotic taxa (α=0.05, LDA score > 2.0) in the group of hypercholesterolemic individuals (Methanosphaera, Rothia, Chromatiales, Clostridiales, Bacillaceae and Coriobacteriaceae) and controls (Faecalibacterium, Victivallis and Selenomonas) at various taxonomic levels. In addition, through the application of Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2 (PICRUSt2), the predominance of pathways related to biosynthesis in hypercholesterolemic patients was established, compared to controls in which degradation pathways were predominant. Finally, in the analysis of co-occurrence networks, it was possible to identify associations between the microorganisms present in both studied groups. Conclusion: Our results point out to unique microbial signatures, which likely play a role on the cholesterol metabolism in the studied population.

Genomic and Phenotypic Insights Into the Potential of Rock Phosphate Solubilizing Bacteria to Promote Millet Growth in vivo.

Rock phosphate (RP) is a natural source of phosphorus for agriculture, with the advantage of lower cost and less impact on the environment when compared to synthetic fertilizers. However, the release of phosphorus (P) from RP occurs slowly, which may limit its short-term availability to crops. Hence, the use of P-solubilizing microorganisms to improve the availability of P from this P source is an interesting approach, as microorganisms often perform other functions that assist plant growth, besides solubilizing P. Here, we describe the characterization of 101 bacterial isolates obtained from the rhizosphere and endosphere of maize plants for their P solubilizing activity in vitro, their growth-promoting activity on millet plants cultivated in soil amended with RP, and their gene content especially associated with phosphate solubilization. For the in vitro solubilization assays, two mineral P sources were used: rock phosphate from Araxá (Brazil) mine (AP) and iron phosphate (Fe-P). The amounts of P released from Fe-P in the solubilization assays were lower than those released from AP, and the endophytic bacteria outperformed the rhizospheric ones in the solubilization of both P sources. Six selected strains were evaluated for their ability to promote the growth of millet in soil fertilized with a commercial rock phosphate (cRP). Two of them, namely Bacillus megaterium UFMG50 and Ochrobactrum pseudogrignonense CNPMS2088, performed better than the others in the cRP assays, improving at least six physiological traits of millet or P content in the soil. Genomic analysis of these bacteria revealed the presence of genes related to P uptake and metabolism, and to organic acid synthesis. Using this approach, we identified six potential candidates as bioinoculants, which are promising for use under field conditions, as they have both the genetic potential and the experimentally demonstrated in vivo ability to improve rock phosphate solubilization and promote plant growth.

Long-Term Rock Phosphate Fertilization Impacts the Microbial Communities of Maize Rhizosphere.

Phosphate fertilization is a common practice in agriculture worldwide, and several commercial products are widely used. Triple superphosphate (TSP) is an excellent soluble phosphorus (P) source. However, its high cost of production makes the long-term use of crude rock phosphate (RP) a more attractive alternative in developing countries, albeit its influence on plant-associated microbiota remains unclear. Here, we compared long-term effects of TSP and RP fertilization on the structure of maize rhizosphere microbial community using next generation sequencing. Proteobacteria were dominant in all conditions, whereas Oxalobacteraceae (mainly Massilia and Herbaspirillum) was enriched in the RP-amended soil. Klebsiella was the second most abundant taxon in the RP-treated soil. Burkholderia sp. and Bacillus sp. were enriched in the RP-amended soil when compared to the TSP-treated soil. Regarding fungi, Glomeromycota showed highest abundance in RP-amended soils, and the main genera were Scutellospora and Racocetra. These taxa are already described as important for P solubilization/acquisition in RP-fertilized soil. Maize grown on TSP and RP-treated soil presented similar productivity, and a positive correlation was detected for P content and the microbial community of the soils. The results suggest changes of the microbial community composition associated to the type of phosphate fertilization. Whilst it is not possible to establish causality relations, our data highlights a few candidate taxa that could be involved in RP solubilization and plant growth promotion. Moreover, this can represent a shorter path for further studies aiming the isolation and validation of the taxa described here concerning P release on the soil plant system and their use as bioinoculants.

Draft Genome Sequence of Hydrotalea flava Strain CCUG 51397T.

We report the draft genome sequence of Hydrotalea flava CCUG 51397(T), the type strain of the genus Hydrotalea (family Chitinophagaceae), isolated from water samples in southern Sweden.

Draft Genome Sequence of a Novel Acidophilic Iron-Oxidizing Firmicutes Species, "Acidibacillus ferrooxidans" (SLC66T).

Here, we present the draft genome sequence of the type strain of "Acidibacillus ferrooxidans," a mesophilic, heterotrophic, and acidophilic bacterium that was isolated from mine spoilage subjected to accelerated weathering in humidity cell tests carried out by the former U.S. Bureau of Mines in Salt Lake City, UT.

Complete mitochondrial genome sequence of Melipona scutellaris, a Brazilian stingless bee.

Melipona scutellaris is a Brazilian stingless bee species and a highly important native pollinator besides its use in rational rearing for honey production. In this study, we present the whole mitochondrial DNA sequence of M. scutellaris from a haploid male. The mitogenome has a size of 14,862 bp and harbors 13 protein-coding genes (PCGs), 2 rRNA genes and 21 tRNA genes.

ZIKV - CDB: A Collaborative Database to Guide Research Linking SncRNAs and ZIKA Virus Disease Symptoms.

BACKGROUND: In early 2015, a ZIKA Virus (ZIKV) infection outbreak was recognized in northeast Brazil, where concerns over its possible links with infant microcephaly have been discussed. Providing a causal link between ZIKV infection and birth defects is still a challenge. MicroRNAs (miRNAs) are small noncoding RNAs (sncRNAs) that regulate post-transcriptional gene expression by translational repression, and play important roles in viral pathogenesis and brain development. The potential for flavivirus-mediated miRNA signalling dysfunction in brain-tissue development provides a compelling hypothesis to test the perceived link between ZIKV and microcephaly. METHODOLOGY/PRINCIPAL FINDINGS: Here, we applied in silico analyses to provide novel insights to understand how Congenital ZIKA Syndrome symptoms may be related to an imbalance in miRNAs function. Moreover, following World Health Organization (WHO) recommendations, we have assembled a database to help target investigations of the possible relationship between ZIKV symptoms and miRNA-mediated human gene expression. CONCLUSIONS/SIGNIFICANCE: We have computationally predicted both miRNAs encoded by ZIKV able to target genes in the human genome and cellular (human) miRNAs capable of interacting with ZIKV genomes. Our results represent a step forward in the ZIKV studies, providing new insights to support research in this field and identify potential targets for therapy.

Preliminary characterization of mitochondrial genome of Melipona scutellaris, a Brazilian stingless bee.

Bees are manufacturers of relevant economical products and have a pollinator role fundamental to ecosystems. Traditionally, studies focused on the genus Melipona have been mostly based on behavioral, and social organization and ecological aspects. Only recently the evolutionary history of this genus has been assessed using molecular markers, including mitochondrial genes. Even though these studies have shed light on the evolutionary history of the Melipona genus, a more accurate picture may emerge when full nuclear and mitochondrial genomes of Melipona species become available. Here we present the assembly, annotation, and characterization of a draft mitochondrial genome of the Brazilian stingless bee Melipona scutellaris using Melipona bicolor as a reference organism. Using Illumina MiSeq data, we achieved the annotation of all protein coding genes, as well as the genes for the two ribosomal subunits (16S and 12S) and transfer RNA genes as well. Using the COI sequence as a DNA barcode, we found that M. cramptoni is the closest species to M. scutellaris.

Genomic plasticity in prokaryotes: the case of the square haloarchaeon.

The variability in genome content among closely related strains of prokaryotes has been one of the most remarkable discoveries of genomics. One way to approach the description of this so-called pan-genome is to compare one reference strain genome with metagenomic sequences from the environment. We have applied this approach to one extreme aquatic habitat, saturated brines in a solar saltern. The genome of Haloquadratum walsbyi strain DSM 16790 was compared to an environmental metagenome obtained from the exact site of its isolation. This approach revealed that some regions of the strain genome were scarcely represented in the metagenome. Here we have analyzed these genomic islands (GI) in the genome of DSM 16790 and compared them with the complete sequence of some fosmids from the environmental library. Two of the islands, GI 2 and GI 4, overlapped with two large guanine and cytosine (GC)-rich regions that showed evidence of high variability through mobile elements. GI 3 seemed to be a phage or phage-remnant acquired by the reference genome, but not present in most environmental lineages. Most differential gene content was related to small molecule transport and detection, probably reflecting adaptation to different pools of organic nutrients. GI 1 did not possess traces of mobile elements and had normal GC content. This island contained the main cluster of cell envelope glycoproteins and the variability found was different from the other GIs. Rather than containing different genes it consisted of homologs with low similarity. This variation might reflect a phage evasion strategy.