Genome analysis of Pseudomonas sp. 14A reveals metabolic capabilities to support epiphytic behavior.

The surface of aboveground plant parts, known as the phyllosphere, is a habitat for various microorganisms called epiphytes establishing biotrophic interactions with their hosts. However, these communities can be affected by environmental and anthropogenic variations such as the application of agrochemicals. Thus, epiphytes have the capacity to survive in such environments. In this study, we obtained the genome of Pseudomonas sp. 14A, an epiphyte isolated from the pepper phyllosphere. The phylogenomic analyses suggested that Pseudomonas sp. 14A may be novel species closely related to P. moraviensis R28-S. Notably, the metabolic pathways proposed consistent with epiphytic lifestyle in Pseudomonas sp. 14A, were shared with other species displaying a different degree of phylogenetic relatedness. Furthermore, variations in configuration of metabolic gene clusters were observed, that could expand microbial metabolic diversity in close relatedness species, highlighting the relevance of microbial diversity associated with plants.

Targeted RNA-Seq Reveals the M. tuberculosis Transcriptome from an In Vivo Infection Model.

The study of host-pathogen interactions using in vivo models with intracellular pathogens like Mycobacterium tuberculosis (Mtb) entails technical limitations, such as: (i) Selecting an efficient differential lysis system to enrich the pathogen cells; (ii) obtaining sufficient high-quality RNA; and (iii) achieving an efficient rRNA depletion. Thus, some authors had used flow cytometers to separate infected cells or significantly increase the sequencing depth of host-pathogen RNA libraries to observe the pathogens' gene expression. However, these options carry additional expenses in specialized equipment typically not available for all laboratories. Here, we propose an experimental protocol involving differential cell lysis and a probe-based ribosomal depletion to determine the gene expression of Mtb and its host during in vivo infection. This method increased the number of observed pathogen-expressed genes from 13 using the traditional RNA-seq approach to 702. After eliminating rRNA reads, we observed that 61.59% of Mtb sequences represented 702 genes, while 38.41% represented intergenic regions. Some of the most expressed genes codified for IS1081 (Rv2512c) transposase and eight PE-PGRS members, such as PGRS49 and PGRS50. As expected, a critical percent of the expressed genes codified for secreted proteins essential for infection, such as PE68, lppN, and LpqH. Moreover, three Mtb ncRNAs were highly expressed (small RNA MTS2823, transfer-messenger RNA RF00023, and ribozyme RF00010). Many of the host-expressed genes were related to the inflammation process and the expression of surfactant proteins such as the Sftpa and Sftpc, known to bind Mtb to alveolar macrophages and mi638, a microRNA with no previous associations with pulmonary diseases. The main objective of this study is to present the method, and a general catalog of the Mtb expressed genes at one point of the in vivo infection. We believe our method represents a different approach to the existing ones to study host-pathogen interactions in tuberculosis and other similar intracellular infections, without the necessity of specialized equipment.

Gut dsDNA virome shows diversity and richness alterations associated with childhood obesity and metabolic syndrome.

Changes in the human gut microbiome are associated with obesity and metabolic syndrome, but the role of the gut virome in both diseases remains largely unknown. We characterized the gut dsDNA virome of 28 school-aged children with healthy normal-weight (NW, n = 10), obesity (O, n = 10), and obesity with metabolic syndrome (OMS, n = 8), using metagenomic sequencing of virus-like particles (VLPs) from fecal samples. The virome classification confirmed the bacteriophages' dominance, mainly composed of Caudovirales. Notably, phage richness and diversity of individuals with O and OMS tended to increase, while the VLP abundance remained the same among all groups. Of the 4,611 phage contigs composing the phageome, 48 contigs were highly prevalent in ≥80% of individuals, suggesting high inter-individual phage diversity. The abundance of several contigs correlated with gut bacterial taxa; and with anthropometric and biochemical parameters altered in O and OMS. To our knowledge, this gut phageome represents one of the largest datasets and suggests disease-specific phage alterations.

Whole-genome of Mexican-crAssphage isolated from the human gut microbiome.

OBJECTIVES: crAssphage is a newly found phage described as the most abundant virus in the human gut microbiome. The majority of the crAssphage proteins are unknown in sequences databases, and its pathogenicity and epidemiology in humans are yet unclear. Hence, being one of the most abundant phages in the human gut microbiome more investigation at the genomic level is necessary to improve our understanding, especially in the Latin American population. DATA DESCRIPTION: In this article, we provide the whole genome of a crAssphage isolated from the human gut microbiome of the Mexican population, which was named Mexican-crAssphage. The genome consists of 96,283 bp, G+C content of 29.24% and 87 coding sequences. Notably, we did not find any transfer RNA genes in the genome sequence. We also sequenced viral-like enriched particles from 28 fecal samples, and we detected the presence of the Mexican-crAssphage genome in 8 samples (28.5%). To our knowledge, our data is the first whole genome report of the crAssphage isolated from the Latin American Population and provides valuable information for the experimental characterization of the most abundant human gut bacteriophage. The whole genome shotgun project of the Mexican-crAssphage is available at DDBJ/ENA/GenBank under the GenBank MK069403.