scholarly journals Complete Genomes of Clade G6 Saccharibacteria Suggest a Divergent Ecological Niche and Lifestyle

mSphere ◽  
2021 ◽  
Author(s):  
Jonathon L. Baker

ABSTRACT Saccharibacteria (formerly TM7) have reduced genomes and a small cell size and appear to have a parasitic lifestyle dependent on a bacterial host. Although there are at least 6 major clades of Saccharibacteria inhabiting the human oral cavity, complete genomes of oral Saccharibacteria were previously limited to the G1 clade. In this study, nanopore sequencing was used to obtain three complete genome sequences from clade G6. Phylogenetic analysis suggested the presence of at least 3 to 5 distinct species within G6, with two discrete taxa represented by the 3 complete genomes. G6 Saccharibacteria were highly divergent from the more-well-studied clade G1 and had the smallest genomes and lowest GC content of all Saccharibacteria . Pangenome analysis showed that although 97% of shared pan- Saccharibacteria core genes and 89% of G1-specific core genes had putative functions, only 50% of the 244 G6-specific core genes had putative functions, highlighting the novelty of this group. Compared to G1, G6 harbored divergent metabolic pathways. G6 genomes lacked an F 1 F o ATPase, the pentose phosphate pathway, and several genes involved in nucleotide metabolism, which were all core genes for G1. G6 genomes were also unique compared to that of G1 in that they encoded d -lactate dehydrogenase, adenylate cyclase, limited glycerolipid metabolism, a homolog to a lipoarabinomannan biosynthesis enzyme, and the means to degrade starch. These differences at key metabolic steps suggest a distinct lifestyle and ecological niche for clade G6, possibly with alternative hosts and/or host dependencies, which would have significant ecological, evolutionary, and likely pathogenic implications. IMPORTANCE Saccharibacteria are ultrasmall parasitic bacteria that are common members of the oral microbiota and have been increasingly linked to disease and inflammation. However, the lifestyle and impact on human health of Saccharibacteria remain poorly understood, especially for the clades with no complete genomes (G2 to G6) or cultured isolates (G2 and G4 to G6). Obtaining complete genomes is of particular importance for Saccharibacteria , because they lack many of the “essential” core genes used for determining draft genome completeness, and few references exist outside clade G1. In this study, complete genomes of 3 G6 strains, representing two candidate species, were obtained and analyzed. The G6 genomes were highly divergent from that of G1 and enigmatic, with 50% of the G6 core genes having no putative functions. The significant difference in encoded functional pathways is suggestive of a distinct lifestyle and ecological niche, probably with alternative hosts and/or host dependencies, which would have major implications in ecology, evolution, and pathogenesis.

2021 ◽  
Author(s):  
Jonathon L. Baker

Saccharibacteria (formerly TM7) have reduced genomes, a small size, and appear to have a parasitic lifestyle dependent on a bacterial host. Although there are at least 6 major clades of Saccharibacteria inhabiting the human oral cavity, cultured isolates or complete genomes of oral Saccharibacteria have been previously limited to the G1 clade. In this study, nanopore sequencing was used to obtain three complete genome sequences from clade G6. Phylogenetic analysis suggested the presence of at least 3-5 distinct species within G6, with two discrete taxa represented by the 3 complete genomes. G6 Saccharibacteria were highly divergent from the more well-studied clade G1, and had the smallest genomes and lowest GC-content of all Saccharibacteria. Pangenome analysis showed that although 97% of shared pan-Saccharibacteria core genes and 89% of G1-specific Core Genes had putative functions, only 50% of the 244 G6-specific Core Genes had putative functions, highlighting the novelty of this group. Compared to G1, G6 encoded divergent metabolic pathways. G6 genomes lacked an F1F0 ATPase, the pentose phosphate pathway, and several genes involved in nucleotide metabolism, which were all core genes for G1. G6 genomes were also unique compared to G1 in that they encoded lactate dehydrogenase, adenylate cyclase, limited glycerolipid metabolism, a homolog to a lipoarabinomannan biosynthesis enzyme, and the means to degrade starch. These differences at key metabolic steps suggest a distinct lifestyle and ecological niche for clade G6, possibly with alternative hosts and/or host-dependencies, which would have significant ecological, evolutionary, and likely pathogenic, implications.


2021 ◽  
pp. 1-13
Author(s):  
Simei Tu ◽  
Hao Zhang ◽  
Xiaocheng Yang ◽  
Wen Wen ◽  
Kangjing Song ◽  
...  

BACKGROUND: Since the molecular mechanisms of cervical cancer (CC) have not been completely discovered, it is of great significance to identify the hub genes and pathways of this disease to reveal the molecular mechanisms of cervical cancer. OBJECTIVE: The study aimed to identify the biological functions and prognostic value of hub genes in cervical cancer. METHODS: The gene expression data of CC patients were downloaded from the Gene Expression Omnibus (GEO) database and The Cancer Genome Atlas (TCGA) database. The core genes were screened out by differential gene expression analysis and weighted gene co-expression network analysis (WGCNA). R software, the STRING online tool and Cytoscape software were used to screen out the hub genes. The GEPIA public database was used to further verify the expression levels of the hub genes in normal tissues and tumour tissues and determine the disease-free survival (DFS) rates of the hub genes. The protein expression of the survival-related hub genes was identified with the Human Protein Atlas (HPA) database. RESULTS: A total of 64 core genes were screened, and 10 genes, including RFC5, POLE3, RAD51, RMI1, PALB2, HDAC1, MCM4, ESR1, FOS and E2F1, were identified as hub genes. Compared with that in normal tissues, RFC5, POLE3, RAD51,RMI1, PALB2, MCM4 and E2F1 were all significantly upregulated in cervical cancer, ESR1 was significantly downregulated in cervical cancer, and high RFC5 expression in CC patients was significantly related to OS. In the DFS analysis, no significant difference was observed in the expression level of RFC5 in cervical cancer patients. Finally, RFC5 protein levels verified by the HPA database were consistently upregulated with mRNA levels in CC samples. CONCLUSIONS: RFC5 may play important roles in the occurrence and prognosis of CC. It could be further explored and validated as a potential predictor and therapeutic target for CC.


2021 ◽  
Vol 10 (48) ◽  
Author(s):  
Sarah Mederos da Silveira ◽  
Sheila da Silva ◽  
Andrew Macrae ◽  
Rommel T. J. Ramos ◽  
Fabrício A. Araújo ◽  
...  

Pseudomonas sp. strain LAP_36 was isolated from rhizosphere soil from Deschampsia antarctica on King George Island, South Shetland Islands, Antarctica. Here, we report on its draft genome sequence, which consists of 8,794,771 bp with 60.0% GC content and 8,011 protein-coding genes.


2019 ◽  
Vol 7 (4) ◽  
pp. 120-124
Author(s):  
Roshna M. Qadir ◽  
Mahde S. Abdulrahman

Obesity represents one of the major problematic health issues worldwide. Recent evidences suggest that obesity is related with the alteration of the oral microbiome. The aim of this study was to measure the salivary bacterial Selenomonas noxia in Duhok population. A total of 155 saliva samples were collected from individuals (aged between 19-35 years) of both genders (86 females and 69 males). The individuals were divided into three groups (obese, overweight, and normal weight) based on their body mass index. Bacterial genomic DNA was extracted from saliva samples. Molecular detections of Selenomonas noxia were performed by the polymerase chain reaction. Among the 155 participants, 34.1% were obese, 26.4% overweight and 39.3% normal weight individuals. The prevalence rate of oral S. noxia among all people was 82.6%. The highest rate of S. noxia was in obese people (86.8%), followed by overweight (85.4%) and normal weight people (77%). The prevalence of S. noxia in overweight people was statistically significant in compare with the normal weight people (p<0.0001). Moreover, the oral carriage of S. noxia was highest among the overweight females (94.5%) followed by obese females (88.9%). However, no significant difference was found compared to males. The result revealed that it is possible to assume that the expansion of S. noxia in saliva is due to obesity. Moreover, the composition of salivary microbiome may lead to the risk that the overweight group is at risk of future obesity. However, further investigations are required with larger sample and participants with different socioeconomic status in order to address the exact link between obesity and oral bacteria. This could lead to a new and promising therapeutic way for improving human's health.  


2021 ◽  
Author(s):  
VISHNU PRASOODANAN P K ◽  
Shruti S. Menon ◽  
Rituja Saxena ◽  
Prashant Waiker ◽  
Vineet K Sharma

Discovery of novel thermophiles has shown promising applications in the field of biotechnology. Due to their thermal stability, they can survive the harsh processes in the industries, which make them important to be characterized and studied. Members of Anoxybacillus are alkaline tolerant thermophiles and have been extensively isolated from manure, dairy-processed plants, and geothermal hot springs. This article reports the assembled data of an aerobic bacterium Anoxybacillus sp. strain MB8, isolated from the Tattapani hot springs in Central India, where the 16S rRNA gene shares an identity of 97% (99% coverage) with Anoxybacillus kamchatkensis strain G10. The de novo assembly and annotation performed on the genome of Anoxybacillus sp. strain MB8 comprises of 2,898,780 bp (in 190 contigs) with a GC content of 41.8% and includes 2,976 protein-coding genes,1 rRNA operon, 73 tRNAs, 1 tm-RNA and 10 CRISPR arrays. The predicted protein-coding genes have been classified into 21 eggNOG categories. The KEGG Automated Annotation Server (KAAS) analysis indicated the presence of assimilatory sulfate reduction pathway, nitrate reducing pathway, and genes for glycoside hydrolases (GHs) and glycoside transferase (GTs). GHs and GTs hold widespread applications, in the baking and food industry for bread manufacturing, and in the paper, detergent and cosmetic industry. Hence, Anoxybacillus sp. strain MB8 holds the potential to be screened and characterized for such commercially relevant enzymes.


2021 ◽  
Vol 12 ◽  
Author(s):  
Scott C. Thomas ◽  
Devon Payne ◽  
Kevin O. Tamadonfar ◽  
Cale O. Seymour ◽  
Jian-Yu Jiao ◽  
...  

Thermoflexus hugenholtzii JAD2T, the only cultured representative of the Chloroflexota order Thermoflexales, is abundant in Great Boiling Spring (GBS), NV, United States, and close relatives inhabit geothermal systems globally. However, no defined medium exists for T. hugenholtzii JAD2T and no single carbon source is known to support its growth, leaving key knowledge gaps in its metabolism and nutritional needs. Here, we report comparative genomic analysis of the draft genome of T. hugenholtzii JAD2T and eight closely related metagenome-assembled genomes (MAGs) from geothermal sites in China, Japan, and the United States, representing “Candidatus Thermoflexus japonica,” “Candidatus Thermoflexus tengchongensis,” and “Candidatus Thermoflexus sinensis.” Genomics was integrated with targeted exometabolomics and 13C metabolic probing of T. hugenholtzii. The Thermoflexus genomes each code for complete central carbon metabolic pathways and an unusually high abundance and diversity of peptidases, particularly Metallo- and Serine peptidase families, along with ABC transporters for peptides and some amino acids. The T. hugenholtzii JAD2T exometabolome provided evidence of extracellular proteolytic activity based on the accumulation of free amino acids. However, several neutral and polar amino acids appear not to be utilized, based on their accumulation in the medium and the lack of annotated transporters. Adenine and adenosine were scavenged, and thymine and nicotinic acid were released, suggesting interdependency with other organisms in situ. Metabolic probing of T. hugenholtzii JAD2T using 13C-labeled compounds provided evidence of oxidation of glucose, pyruvate, cysteine, and citrate, and functioning glycolytic, tricarboxylic acid (TCA), and oxidative pentose-phosphate pathways (PPPs). However, differential use of position-specific 13C-labeled compounds showed that glycolysis and the TCA cycle were uncoupled. Thus, despite the high abundance of Thermoflexus in sediments of some geothermal systems, they appear to be highly focused on chemoorganotrophy, particularly protein degradation, and may interact extensively with other microorganisms in situ.


2021 ◽  
Author(s):  
Veilumuthu P ◽  
Nagarajan T ◽  
Sasikumar S ◽  
Siva R ◽  
J Godwin Christopher

Abstract Streptomyces species is one among the dominant group of bacteria in the family Actinobacteria with a rich repertoire of secondary metabolites. Secondary metabolites with antimicrobial activity and plant growth promotor have been isolated from various Streptomyces sp. Here in this investigation, we present the draft genome of a new species, Streptomyces sp. VITGV156 isolated from healthy tomato plant (Lycopersicon esculentum) which has some rare antimicrobial secondary metabolites, like coelichelin, fluostatins, vicenistatin, nystatin, sipanmycin, and informatipeptin. The genome is 8.18 Mb in size with 6,259 protein coding genes. The average GC content of the genome is 72.61 %. Preliminary analysis with antiSMASH 6.0 revealed the presence of 29 biosynthetic gene clusters for the synthesis of potential secondary metabolites. These includes 4 NRPS (non – ribosomal peptide synthetase), 7 PKS (Polyketide Synthases), 2 RiPP (Ribosomally synthesized and post-translationally modified peptides) clusters. When we look into genes associated with secondary metabolites, 406 genes are present which includes 184 genes for cofactor and vitamins, 72 genes for terpenoids and polyketides, 70 genes for xenobiotics and 80 genes for other metabolites are present. Comparative genome analysis of VITGV156 with its closest neighbor Streptomyces luteus strain TRM45540 revealed ANI 91.22% and dDDH value 44.00%.


2021 ◽  
Vol 10 (16) ◽  
Author(s):  
Zhenhua Yu ◽  
Sergio de los Santos-Villalobos ◽  
Yansheng Li ◽  
Jian Jin ◽  
Fannie Isela Parra Cota ◽  
...  

ABSTRACT Here, we present the draft genome of Bacillus sp. strain IGA-FME-2. This strain was isolated from the bulk soil of soybean (Glycine max L.). Its genome consists of 3,810 protein-coding genes, 44 tRNAs, two 16S rRNAs, and a single copy of 23S rRNA, with a GC content of 46.4%.


2020 ◽  
pp. 1-14
Author(s):  
K.M. Damitha Gunathilake ◽  
Anupama P. Halmillawewa ◽  
Keith D. MacKenzie ◽  
Benjamin J. Perry ◽  
Christopher K. Yost ◽  
...  

Mesorhizobium phage vB_MloS_Cp1R7A-A1 was isolated from soil planted with chickpea in Saskatchewan. It is dissimilar in sequence and morphology to previously described rhizobiophages. It is a B3 morphotype virus with a distinct prolate capsid and belongs to the tailed phage family Siphoviridae. Its genome has a GC content of 60.3% and 238 predicted genes. Putative functions were predicted for 57 genes, which include 27 tRNA genes with anticodons corresponding to 18 amino acids. This represents the highest number of tRNA genes reported yet in a rhizobiophage. The gene arrangement shows a partially modular organization. Most of the structural genes are found in one module, whereas tRNA genes are in another. Genes for replication, recombination, and nucleotide metabolism form the third module. The arrangement of the replication module resembles the replication module of Enterobacteria phage T5, raising the possibility that it uses a recombination-based replication mechanism, but there is also a suggestion that a T7-like replication mechanism could be used. Phage termini appear to be long direct repeats of just over 12 kb in length. Phylogenetic analysis revealed that Cp1R7A-A1 is more closely related to PhiCbK-like Caulobacter phages and other B3 morphotype phages than to other rhizobiophages sequenced thus far.


2021 ◽  
Vol 10 (20) ◽  
Author(s):  
M. M. A. Khan ◽  
Jin Duan ◽  
Bernard R. Glick ◽  
Patrick M. Finnegan ◽  
Saleh A. Kabli ◽  
...  

ABSTRACT Pseudomonas pseudoalcaligenes KB-10 can enhance salinity tolerance in coriander plants. We report a draft genome sequence of P. pseudoalcaligenes KB-10, comprising a 5,241,174-bp circular chromosome containing 4,921 genes, with a GC content of 62.97%.


Sign in / Sign up

Export Citation Format

Share Document