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July 7, 2019

Culture- and metagenomics-enabled analyses of the Methanosphaera genus reveals their monophyletic origin and differentiation according to genome size.

The genus Methanosphaera is a well-recognized but poorly characterized member of the mammalian gut microbiome, and distinctive from Methanobrevibacter smithii for its ability to induce a pro-inflammatory response in humans. Here we have used a combination of culture- and metagenomics-based approaches to expand the representation and information for the genus, which has supported the examination of their phylogeny and physiological capacity. Novel isolates of the genus Methanosphaera were recovered from bovine rumen digesta and human stool, with the bovine isolate remarkable for its large genome size relative to other Methanosphaera isolates from monogastric hosts. To substantiate this observation, we then recovered seven high-quality Methanosphaera-affiliated population genomes from ruminant and human gut metagenomic datasets. Our analyses confirm a monophyletic origin of Methanosphaera spp. and that the colonization of monogastric and ruminant hosts favors representatives of the genus with different genome sizes, reflecting differences in the genome content needed to persist in these different habitats.


July 7, 2019

Complete genome sequence of an avian native NDM-1-producing Salmonella enterica subsp. enterica serovar Corvallis strain.

Carbapenems are an important class of ß-lactams and one of the last options for treating severe human infections. We present here the complete genome sequence of avian native carbapenemase-producing Salmonella enterica subsp. enterica serovar Corvallis strain 12-01738, harboring a blaNDM-1-carrying IncA/C2 plasmid, isolated in 2012 from a wild bird (Milvus migrans) in Germany. Copyright © 2018 Hadziabdic et al.


July 7, 2019

Complete genome sequence of industrial biocontrol strain Paenibacillus polymyxa HY96-2 and further analysis of Its biocontrol mechanism.

Paenibacillus polymyxa (formerly known as Bacillus polymyxa) has been extensively studied for agricultural applications as a plant-growth-promoting rhizobacterium and is also an important biocontrol agent. Our team has developed the P. polymyxa strain HY96-2 from the tomato rhizosphere as the first microbial biopesticide based on P. polymyxa for controlling plant diseases around the world, leading to the commercialization of this microbial biopesticide in China. However, further research is essential for understanding its precise biocontrol mechanisms. In this paper, we report the complete genome sequence of HY96-2 and the results of a comparative genomic analysis between different P. polymyxa strains. The complete genome size of HY96-2 was found to be 5.75 Mb and 5207 coding sequences were predicted. HY96-2 was compared with seven other P. polymyxa strains for which complete genome sequences have been published, using phylogenetic tree, pan-genome, and nucleic acid co-linearity analysis. In addition, the genes and gene clusters involved in biofilm formation, antibiotic synthesis, and systemic resistance inducer production were compared between strain HY96-2 and two other strains, namely, SC2 and E681. The results revealed that all three of the P. polymyxa strains have the ability to control plant diseases via the mechanisms of colonization (biofilm formation), antagonism (antibiotic production), and induced resistance (systemic resistance inducer production). However, the variation of the corresponding genes or gene clusters between the three strains may lead to different antimicrobial spectra and biocontrol efficacies. Two possible pathways of biofilm formation in P. polymyxa were reported for the first time after searching the KEGG database. This study provides a scientific basis for the further optimization of the field applications and quality standards of industrial microbial biopesticides based on HY96-2. It may also serve as a reference for studying the differences in antimicrobial spectra and biocontrol capability between different biocontrol agents.


July 7, 2019

Bioaugmentated activated sludge degradation of progesterone: Kinetics and mechanism

Progesterone (PGT) is not completely removed in conventional treatment plants, and the processing results may have adverse effects on aquatic organisms. In this study, an effective PGT-degradation bacterium, Rhodococcus sp. HYW, was newly isolated from the pharmaceutical plant and was used to augment degradation of PGT. When grown in a mineral medium (MM) containing a trace amount of PGT (500?µg/L) as the sole carbon and energy source, the results show that 99% of PGT was degraded within 1?h and followed the first-order reaction kinetics. Bioaugmentation of PGT-contaminated activated sludge greatly enhanced the PGT degradation rate (~91%) and its derivatives degradation rate were also greatly improved (>83%). The process of PGT degradation in non-bioaugmented PGT-contaminated activated sludge (NBS) and bioaugmentation activated sludge with the bacterial consortium(BS) also conforms to the first-order kinetic model. Furthermore, 12 and 11 biodegradation products for PGT in the NBS and BS were identified using HPLC-LTQ-Orbitrap XL™, respectively. Based on these biodegradation products, two degradation pathways for PGT in NBS and BS were proposed, respectively. Comparing the degradation kinetics and metabolites, it was found that BS degrades PGT more rapidly and can further convert PGT to a small molecular acid. Finally, to reveal the probable cause for the differences in the PGT degradation efficiency and products in the NBS and BS.


July 7, 2019

Complete genome sequence of Kocuria rhizophila BT304, isolated from the small intestine of castrated beef cattle.

Members of the species Kocuria rhizophila, belonging to the family Micrococcaceae in the phylum Actinobacteria, have been isolated from a wide variety of natural sources, such as soil, freshwater, fish gut, and clinical specimens. K. rhizophila is important from an industrial viewpoint, because the bacterium grows rapidly with high cell density and exhibits robustness at various growth conditions. However, the bacterium is an opportunistic pathogen involved in human infections. Here, we sequenced and analyzed the genome of the K. rhizophila strain BT304, isolated from the small intestine of adult castrated beef cattle.The genome of K. rhizophila BT304 consisted of a single circular chromosome of 2,763,150 bp with a GC content of 71.2%. The genome contained 2359 coding sequences, 51 tRNA genes, and 9 rRNA genes. Sequence annotations with the RAST server revealed many genes related to amino acid, carbohydrate, and protein metabolism. Moreover, the genome contained genes related to branched chain amino acid biosynthesis and degradation. Analysis of the OrthoANI values revealed that the genome has high similarity (>?97.8%) with other K. rhizophila strains, such as DC2201, FDAARGOS 302, and G2. Comparative genomic analysis further revealed that the antibiotic properties of K. rhizophila vary among the strains.The relatively small number of virulence-related genes and the great potential in production of host available nutrients suggest potential application of the BT304 strain as a probiotic in breeding beef cattle.


July 7, 2019

Near-complete genome sequence of Ralstonia solanacearum T523, a phylotype I tomato phytopathogen isolated from the Philippines.

Ralstonia solanacearum strain T523 is the major phytopathogen causing tomato bacterial wilt in the Philippines. Here, we report the complete chromosome and draft megaplasmid genomes with predicted gene inventories supporting rhizo- sphere processes, extensive plant virulence effectors, and the production of bioac- tive signaling metabolites, such as ralstonin, micacocidin, and homoserine lactone.


July 7, 2019

Complete genome sequence of Moraxella bovis strain Epp-63 (300), an etiologic agent of infectious bovine keratoconjunctivitis.

We report here the complete closed genome sequence of Moraxella bo- vis strain Epp-63 (300) (Epp63). This strain was isolated from an infectious bovine keratoconjunctivitis (IBK) case in 1963. Since then, Epp63 has been used extensively for IBK research. Consequently, the genome sequence of Epp63 should help eluci- date IBK host-pathogen interactions.


July 7, 2019

Closed genome sequences and antibiograms of 16 Pasteurella multocida isolates from bovine respiratory disease complex cases and apparently healthy controls.

Pasteurella multocida is an animal-associated Gram-negative member of the Pasteurellaceae family. It is an opportunistic pathogen and is one of the principal bacterial species contributing to bovine respiratory disease complex (BRDC) in feedlot cattle. We present 16 closed genome sequences and antibiograms of isolates cultured from calves exhibiting clinical signs of BRDC and from control calves not showing signs of BRDC.


July 7, 2019

New variant of multidrug-resistant Salmonella enterica serovar Typhimurium associated with invasive disease in immunocompromised patients in Vietnam.

Nontyphoidal Salmonella (NTS), particularly Salmonella enterica serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in sub-Saharan Africa. In contrast, S Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in S Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal S Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of S Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of S Typhimurium (serovar I:4,[5],12:i:- sequence type 34 [ST34]) has been introduced into Vietnam, reacquired a phase 2 flagellum, and acquired an IncHI2 multidrug-resistant plasmid. Notably, these novel biphasic ST34 S Typhimurium variants were significantly associated with iNTS in Vietnamese HIV-infected patients. Our study represents the first characterization of novel iNTS organisms isolated outside sub-Saharan Africa and outlines a new pathway for the emergence of alternative Salmonella variants into susceptible human populations.IMPORTANCESalmonella Typhimurium is a major diarrheal pathogen and associated with invasive nontyphoid Salmonella (iNTS) disease in vulnerable populations. We present the first characterization of iNTS organisms in Southeast Asia and describe a different evolutionary trajectory from that of organisms causing iNTS in sub-Saharan Africa. In Vietnam, the globally distributed monophasic variant of Salmonella Typhimurium, the serovar I:4,[5],12:i:- ST34 clone, has reacquired a phase 2 flagellum and gained a multidrug-resistant plasmid to become associated with iNTS disease in HIV-infected patients. We document distinct communities of S Typhimurium and I:4,[5],12:i:- in animals and humans in Vietnam, despite the greater mixing of these host populations here. These data highlight the importance of whole-genome sequencing surveillance in a One Health context in understanding the evolution and spread of resistant bacterial infections. Copyright © 2018 Mather et al.


July 7, 2019

Genomic insights into date palm origins.

With the development of next-generation sequencing technology, the amount of date palm (Phoenix dactylifera L.) genomic data has grown rapidly and yielded new insights into this species and its origins. Here, we review advances in understanding of the evolutionary history of the date palm, with a particular emphasis on what has been learned from the analysis of genomic data. We first record current genomic resources available for date palm including genome assemblies and resequencing data. We discuss new insights into its domestication and diversification history based on these improved genomic resources. We further report recent discoveries such as the existence of wild ancestral populations in remote locations of Oman and high differentiation between African and Middle Eastern populations. While genomic data are consistent with the view that domestication took place in the Gulf region, they suggest that the process was more complex involving multiple gene pools and possibly a secondary domestication. Many questions remain unanswered, especially regarding the genetic architecture of domestication and diversification. We provide a road map to future studies that will further clarify the domestication history of this iconic crop.


July 7, 2019

Whole-genome sequence of purple non-sulfur bacteria, Rhodobacter sphaeroides strain MBTLJ-8 with improved CO2 reduction capacity.

Rhodobacter sphaeroides consists of two chromosomes and many plasmids and incorporates many environmentally important functional gene. Rhodobacter sphaeroides MBTLJ-8 was derived from R. sphaeroides 2.4.1 using chemical mutagenesis and is characterized by enhanced production of physiological active compounds as well as improved carbon dioxide reduction capacity. We reported the complete genome sequence and characteristics based on genomic information of this bacteria. Therefore, this genome sequence provides elucidation for improved CO2 fixation and enhanced physiological active compounds production, and will be used as the efficient photosynthetic bacteria for the biological CO2 reduction system. Copyright © 2018 Elsevier B.V. All rights reserved.


July 7, 2019

Signatures of selection and environmental adaptation across the goat genome post-domestication.

Since goat was domesticated 10,000 years ago, many factors have contributed to the differentiation of goat breeds and these are classified mainly into two types: (i) adaptation to different breeding systems and/or purposes and (ii) adaptation to different environments. As a result, approximately 600 goat breeds have developed worldwide; they differ considerably from one another in terms of phenotypic characteristics and are adapted to a wide range of climatic conditions. In this work, we analyzed the AdaptMap goat dataset, which is composed of data from more than 3000 animals collected worldwide and genotyped with the CaprineSNP50 BeadChip. These animals were partitioned into groups based on geographical area, production uses, available records on solid coat color and environmental variables including the sampling geographical coordinates, to investigate the role of natural and/or artificial selection in shaping the genome of goat breeds.Several signatures of selection on different chromosomal regions were detected across the different breeds, sub-geographical clusters, phenotypic and climatic groups. These regions contain genes that are involved in important biological processes, such as milk-, meat- or fiber-related production, coat color, glucose pathway, oxidative stress response, size, and circadian clock differences. Our results confirm previous findings in other species on adaptation to extreme environments and human purposes and provide new genes that could explain some of the differences between goat breeds according to their geographical distribution and adaptation to different environments.These analyses of signatures of selection provide a comprehensive first picture of the global domestication process and adaptation of goat breeds and highlight possible genes that may have contributed to the differentiation of this species worldwide.


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