Genomic insights into Mycobacterium simiae human colonization

Metagenomic views on taxonomic and functional profiles of the Himalayan Tsomgo cold lake and unveiling its deterzome potential

Cold habitat is considered a potential source for detergent industry enzymes. This study aims at the metagenomic investigation of Tsomgo lake for taxonomic and functional annotation, unveiling the deterzome potential of the residing microbiota at this site. The present investigation revealed molecular profiling of microbial community structure and functional potential of the high-altitude Tsomgo lake samples of two different temperatures, harvested during March and August. Bacteria were found to be the most dominant phyla, with traces of genomic pieces of evidence belonging to archaea, viruses, and eukaryotes. Proteobacteria and Actinobacteria were noted to be the most abundant bacterial phyla in the cold lake. In-depth metagenomic investigation of the cold aquatic habitat revealed novel genes encoding detergent enzymes, amylase, protease, and lipase. Further, metagenome-assembled genomes (MAGs) belonging to the psychrophilic bacterium, Arthrobacter alpinus, were constructed from the metagenomic data. The annotation depicted the presence of detergent enzymes and genes for low-temperature adaptation in Arthrobacter alpinus. Psychrophilic microbial isolates were screened for lipase, protease, and amylase activities to further strengthen the metagenomic findings. A novel strain of Acinetobacter sp. was identified with the dual enzymatic activity of protease and amylase. The bacterial isolates exhibited hydrolyzing activity at low temperatures. This metagenomic study divulged novel genomic resources for detergent industry enzymes, and the bacterial isolates secreting cold-active amylase, lipase, and protease enzymes. The findings manifest that Tsomgo lake is a potential bioresource of cold-active enzymes, vital for various industrial applications.

Genomic characterization of denitrifying methylotrophic Pseudomonas aeruginosa strain AAK/M5 isolated from municipal solid waste landfill soil

Municipal landfills are known for methane production and a source of nitrate pollution leading to various environmental issues. Therefore, this niche was selected for the isolation of one-carbon (C1) utilizing bacteria with denitrifying capacities using anaerobic enrichment on nitrate mineral salt medium supplemented with methanol as carbon source. Eight axenic cultures were isolated of which, isolate AAK/M5 demonstrated the highest methanol removal (73.28%) in terms of soluble chemical oxygen demand and methane removal (41.27%) at the expense of total nitrate removal of 100% and 33% respectively. The whole genome characterization with phylogenomic approach suggested that the strain AAK/M5 could be assigned to Pseudomonas aeruginosa with close neighbours as type strains DVT779, AES1M, W60856, and LES400. The circular genome annotation showed the presence of complete set of genes essential for methanol utilization and complete denitrification process. The study demonstrates the potential of P. aeruginosa strain AAK/M5 in catalysing methane oxidation thus serving as a methane sink vis-à-vis utilization of nitrate. Considering the existence of such bacteria at landfill site, the study highlights the need to develop strategies for their enrichment and designing of efficient catabolic activity for such environments.

The first diagnostic test for specific detection of Mycobacterium simiae using an electrochemical label-free DNA nanobiosensor

Mycobacterium simiae has been reported to be the most prevalent species of Nontuberculous mycobacteria (NTM) in many countries. As both phenotypic and molecular detection of M. simiae and other NTMs have limitations, finding an accurate, fast, and low-cost diagnostic method is critical for the management of infections. Here, we report the development of a new type of label-free electrochemical biosensor using a gold electrode decorated with l-cysteine/PAMAM dendrimer for specific targeting of M. simiae ITS sequence. DNA hybridization was monitored by measuring changes in the free guanine electrical signal with changing ssDNA target concentrations by differential pulse voltammetry (DPV) method. Response surface methodology (RSM) was applied for the optimization of variables affecting biosensor response. Under optimal conditions, the biosensor revealed a wide linear range from 10^-14 M to 10^-6 M and a detection limit of 1.40 fM. The fabricated biosensor showed an excellent selectivity to M. simiae in the presence of other similar pathogenic bacteria. Moreover, experimental results confirmed that this biosensor exhibited great precision and high reproducibility, hence provides a low-cost, label-free, and faster detection analysis, representing a novel strategy in detecting other NTMs.

Genome-wide identification and function analysis of HMAD gene family in cotton (Gossypium spp.)

BACKGROUND

The abiotic stress such as soil salinization and heavy metal toxicity has posed a major threat to sustainable crop production worldwide. Previous studies revealed that halophytes were supposed to tolerate other stress including heavy metal toxicity. Though HMAD (heavy-metal-associated domain) was reported to play various important functions in Arabidopsis, little is known in Gossypium.

RESULTS

A total of 169 G. hirsutum genes were identified belonging to the HMAD gene family with the number of amino acids ranged from 56 to 1011. Additionally, 84, 76 and 159 HMAD genes were identified in each G. arboreum, G. raimondii and G. barbadense, respectively. The phylogenetic tree analysis showed that the HMAD gene family were divided into five classes, and 87 orthologs of HMAD genes were identified in four Gossypium species, such as genes Gh_D08G1950 and Gh_A08G2387 of G. hirsutum are orthologs of the Gorai.004G210800.1 and Cotton_A_25987 gene in G. raimondii and G. arboreum, respectively. In addition, 15 genes were lost during evolution. Furthermore, conserved sequence analysis found the conserved catalytic center containing an anion binding (CXXC) box. The HMAD gene family showed a differential expression levels among different tissues and developmental stages in G. hirsutum with the different cis-elements for abiotic stress.

CONCLUSIONS

Current study provided important information about HMAD family genes under salt-stress in Gossypium genome, which would be useful to understand its putative functions in different species of cotton.

Performance and mechanisms for V(v) bio-reduction by straw: key influencing factors

A high concentration of vanadium [V(v)] in groundwater is extremely harmful for humans. Weak movability and low toxicity after microbial V(v) reduction have attracted remarkable attention, especially for using solid carbon sources. However, the influencing factors remain unclear. In this study, the initial V(v) concentration, inocula amount and straw dosage were examined to ascertain the mechanisms behind them. Increasing the initial V(v) concentration led to the decrease of the V(v) removal efficiency, which was also positively correlated with the straw dosage within a certain range. The initial sludge amount was not a main factor affecting microbial V(v) removal in this study. With the initial amount of 10 mg L^-1 V(v), 25 mL initial inocula and 5 g straw, 88.2% of V(v) was removed. According to the dissolved organic matter (DOM) analysis results, microbial activity prevailed in groups with higher V(v) removal efficiency, indicating that the V(v) bio-reduction was attributed to the microbial activity, which was considered a major factor. Functional species as unclassified_f_Enterobacteriaceae presumably contributed to the V(v) bioreduction, with upregulated ABC transporter genes and enzymes.

Draft Genome Sequence of Mycobacterium simiae, a Potential Pathogen Isolated from the Normal Human Oral Cavity

We report the draft genome sequence of Mycobacterium simiae, a slowly growing nontuberculous mycobacterium (NTM) isolated from a mouthwash sample of a healthy person. This genome of 6,603,693 bp exhibited a 66.13% GC content and 6,391 genes with 6,257 coding sequences, 3 rRNAs, and 78 tRNAs.

We report the draft genome sequence of Mycobacterium simiae, a slowly growing nontuberculous mycobacterium (NTM) isolated from a mouthwash sample of a healthy person. This genome of 6,603,693 bp exhibited a 66.13% GC content and 6,391 genes with 6,257 coding sequences, 3 rRNAs, and 78 tRNAs.

Meeting report of the third annual Tri-Service Microbiome Consortium symposium

The Tri-Service Microbiome Consortium (TSMC) was founded to enhance collaboration, coordination, and communication of microbiome research among U.S. Department of Defense (DoD) organizations and to facilitate resource, material and information sharing among consortium members. The 2019 annual symposium was held 22-24 October 2019 at Wright-Patterson Air Force Base in Dayton, OH. Presentations and discussions centered on microbiome-related topics within five broad thematic areas: 1) human microbiomes; 2) transitioning products into Warfighter solutions; 3) environmental microbiomes; 4) engineering microbiomes; and 5) microbiome simulation and characterization. Collectively, the symposium provided an update on the scope of current DoD microbiome research efforts, highlighted innovative research being done in academia and industry that can be leveraged by the DoD, and fostered collaborative opportunities. This report summarizes the presentations and outcomes of the 3rd annual TSMC symposium.

A mycobacterial disease is associated with the silent mass mortality of the pen shell Pinna nobilis along the Tyrrhenian coastline of Italy

Disease is an increasing threat for marine bivalves worldwide. Recently, a mass mortality event (MME) impacting the bivalve Pinna nobilis was detected across a wide geographical area of the Spanish Mediterranean Sea and linked to a haplosporidian parasite. In 2017–2018, mass mortality events affecting the pen shell Pinna nobilis were recorded in two different regions of Italy, Campania and Sicily, in the Tyrrhenian Sea (Mediterranean Sea). Histopathological and molecular examinations of specimens showed the presence of Haplosporidium sp. in only one specimen in one area. Conversely, in all of the surveyed moribund animals, strong inflammatory lesions at the level of connective tissue surrounding the digestive system and gonads and linked to the presence of intracellular Zhiel-Neelsen-positive bacteria were observed. Molecular analysis of all of the diseased specimens (13) confirmed the presence of a Mycobacterium. Blast analysis of the sequences from all of the areas revealed that they were grouped together with the human mycobacterium M. sherrisii close to the group including M. shigaense, M. lentiflavum and M. simiae. Based on pathological and molecular findings, it is proposed that a mycobacterial disease is associated with the mortality episodes of Pinna nobilis, indicating that, at this time, Haplosporidium sp. is not responsible for these events in Campanian and Sicilian waters.