scholarly journals Decoding the Genomic Variability among Members of the Bifidobacterium dentium Species

2020 ◽  
Vol 8 (11) ◽  
pp. 1720
Author(s):  
Gabriele Andrea Lugli ◽  
Chiara Tarracchini ◽  
Giulia Alessandri ◽  
Christian Milani ◽  
Leonardo Mancabelli ◽  
...  

Members of the Bifidobacterium dentium species are usually identified in the oral cavity of humans and associated with the development of plaque and dental caries. Nevertheless, they have also been detected from fecal samples, highlighting a widespread distribution among mammals. To explore the genetic variability of this species, we isolated and sequenced the genomes of 18 different B. dentium strains collected from fecal samples of several primate species and an Ursus arctos. Thus, we investigated the genomic variability and metabolic abilities of the new B. dentium isolates together with 20 public genome sequences. Comparative genomic analyses provided insights into the vast metabolic repertoire of the species, highlighting 19 glycosyl hydrolases families shared between each analyzed strain. Phylogenetic analysis of the B. dentium taxon, involving 1140 conserved genes, revealed a very close phylogenetic relatedness among members of this species. Furthermore, low genomic variability between strains was also confirmed by an average nucleotide identity analysis showing values higher than 98.2%. Investigating the genetic features of each strain, few putative functional mobile elements were identified. Besides, a consistent occurrence of defense mechanisms such as CRISPR–Cas and restriction–modification systems may be responsible for the high genome synteny identified among members of this taxon.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Josué Barrera-Redondo ◽  
Guillermo Sánchez-de la Vega ◽  
Jonás A. Aguirre-Liguori ◽  
Gabriela Castellanos-Morales ◽  
Yocelyn T. Gutiérrez-Guerrero ◽  
...  

AbstractDespite their economic importance and well-characterized domestication syndrome, the genomic impact of domestication and the identification of variants underlying the domestication traits in Cucurbita species (pumpkins and squashes) is currently lacking. Cucurbita argyrosperma, also known as cushaw pumpkin or silver-seed gourd, is a Mexican crop consumed primarily for its seeds rather than fruit flesh. This makes it a good model to study Cucurbita domestication, as seeds were an essential component of early Mesoamerican diet and likely the first targets of human-guided selection in pumpkins and squashes. We obtained population-level data using tunable Genotype by Sequencing libraries for 192 individuals of the wild and domesticated subspecies of C. argyrosperma across Mexico. We also assembled the first high-quality wild Cucurbita genome. Comparative genomic analyses revealed several structural variants and presence/absence of genes related to domestication. Our results indicate a monophyletic origin of this domesticated crop in the lowlands of Jalisco. We found evidence of gene flow between the domesticated and wild subspecies, which likely alleviated the effects of the domestication bottleneck. We uncovered candidate domestication genes that are involved in the regulation of growth hormones, plant defense mechanisms, seed development, and germination. The presence of shared selected alleles with the closely related species Cucurbita moschata suggests domestication-related introgression between both taxa.


2020 ◽  
Author(s):  
Robert A. Petit ◽  
Timothy D. Read

AbstractSequencing of bacterial genomes using Illumina technology has become such a standard procedure that often data are generated faster than can be conveniently analyzed. We created a new series of pipelines called Bactopia, built using Nextflow workflow software, to provide efficient comparative genomic analyses for bacterial species or genera. Bactopia consists of a dataset setup step (Bactopia Datasets; BaDs) where a series of customizable datasets are created for the species of interest; the Bactopia Analysis Pipeline (BaAP), which performs quality control, genome assembly and several other functions based on the available datasets and outputs the processed data to a structured directory format; and a series of Bactopia Tools (BaTs) that perform specific post-processing on some or all of the processed data. BaTs include pan-genome analysis, computing average nucleotide identity between samples, extracting and profiling the 16S genes and taxonomic classification using highly conserved genes. It is expected that the number of BaTs will increase to fill specific applications in the future. As a demonstration, we performed an analysis of 1,664 public Lactobacillus genomes, focusing on L. crispatus, a species that is a common part of the human vaginal microbiome. Bactopia is an open source system that can scale from projects as small as one bacterial genome to thousands that allows for great flexibility in choosing comparison datasets and options for downstream analysis. Bactopia code can be accessed at https://www.github.com/bactopia/bactopia.


2020 ◽  
Author(s):  
Josué Barrera-Redondo ◽  
Guillermo Sánchez-de la Vega ◽  
Jonás A. Aguirre-Liguori ◽  
Gabriela Castellanos-Morales ◽  
Yocelyn T. Gutiérrez-Guerrero ◽  
...  

AbstractDespite their economic importance and well-characterized domestication syndrome, the genomic impact of domestication and the identification of variants underlying the domestication traits in Cucurbita species (pumpkins and squashes) is currently lacking. Cucurbita argyrosperma, also known as cushaw pumpkin or silver-seed gourd, is a Mexican crop consumed primarily for its seeds rather than fruit flesh. This makes it a good model to study Cucurbita domestication, as seeds were an essential component of early Mesoamerican diet and likely the first targets of human-guided selection in pumpkins and squashes. We obtained population-level data using tunable Genotype by Sequencing libraries for 192 individuals of the wild and domesticated subspecies of C. argyrosperma across Mexico. We also assembled the first wild Cucurbita genome at a chromosome level. Comparative genomic analyses revealed several structural variants and presence/absence of genes related to domestication. Our results indicate a monophyletic origin of this domesticated crop in the lowlands of Jalisco. We uncovered candidate domestication genes that are involved in the synthesis and regulation of growth hormones, plant defense mechanisms, flowering time and seed development. The presence of shared selected alleles with the closely related species Cucurbita moschata suggests domestication-related introgression between both taxa.


2010 ◽  
Vol 78 (4) ◽  
pp. 1760-1771 ◽  
Author(s):  
S. M. Szczepanek ◽  
E. R. Tulman ◽  
T. S. Gorton ◽  
X. Liao ◽  
Z. Lu ◽  
...  

ABSTRACT Mycoplasma gallisepticum is a significant respiratory and reproductive pathogen of domestic poultry. While the complete genomic sequence of the virulent, low-passage M. gallisepticum strain R (Rlow) has been reported, genomic determinants responsible for differences in virulence and host range remain to be completely identified. Here, we utilize genome sequencing and microarray-based comparative genomic data to identify these genomic determinants of virulence and to elucidate genomic variability among strains of M. gallisepticum. Analysis of the high-passage, attenuated derivative of Rlow, Rhigh, indicated that relatively few total genomic changes (64 loci) occurred, yet they are potentially responsible for the observed attenuation of this strain. In addition to previously characterized mutations in cytadherence-related proteins, changes included those in coding sequences of genes involved in sugar metabolism. Analyses of the genome of the M. gallisepticum vaccine strain F revealed numerous differences relative to strain R, including a highly divergent complement of vlhA surface lipoprotein genes, and at least 16 genes absent or significantly fragmented relative to strain R. Notably, an Rlow isogenic mutant in one of these genes (MGA_1107) caused significantly fewer severe tracheal lesions in the natural host compared to virulent M. gallisepticum Rlow. Comparative genomic hybridizations indicated few genetic loci commonly affected in F and vaccine strains ts-11 and 6/85, which would correlate with proteins affecting strain R virulence. Together, these data provide novel insights into inter- and intrastrain M. gallisepticum genomic variability and the genetic basis of M. gallisepticum virulence.


Gene ◽  
2021 ◽  
pp. 145715
Author(s):  
Ying Zhang ◽  
Zhengfeng Wang ◽  
Yanan Guo ◽  
Sheng Chen ◽  
Xianyi Xu ◽  
...  

2021 ◽  
Author(s):  
Yang Liu ◽  
Wei Xiao ◽  
Leilei Yu ◽  
Fengwei Tian ◽  
Gang Wang ◽  
...  

Irritable bowel syndrome (IBS) is a chronic intestinal disorder accompanied by low-grade inflammation, visceral hypersensitivity, and gut microbiota dysbiosis. Several studies have indicated that Lactobacillus supplementation can help to alleviate...


Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 63
Author(s):  
Lakshminarayan M. Iyer ◽  
Vivek Anantharaman ◽  
Arunkumar Krishnan ◽  
A. Maxwell Burroughs ◽  
L. Aravind

Jumbo phages have attracted much attention by virtue of their extraordinary genome size and unusual aspects of biology. By performing a comparative genomics analysis of 224 jumbo phages, we suggest an objective inclusion criterion based on genome size distributions and present a synthetic overview of their manifold adaptations across major biological systems. By means of clustering and principal component analysis of the phyletic patterns of conserved genes, all known jumbo phages can be classified into three higher-order groups, which include both myoviral and siphoviral morphologies indicating multiple independent origins from smaller predecessors. Our study uncovers several under-appreciated or unreported aspects of the DNA replication, recombination, transcription and virion maturation systems. Leveraging sensitive sequence analysis methods, we identify novel protein-modifying enzymes that might help hijack the host-machinery. Focusing on host–virus conflicts, we detect strategies used to counter different wings of the bacterial immune system, such as cyclic nucleotide- and NAD+-dependent effector-activation, and prevention of superinfection during pseudolysogeny. We reconstruct the RNA-repair systems of jumbo phages that counter the consequences of RNA-targeting host effectors. These findings also suggest that several jumbo phage proteins provide a snapshot of the systems found in ancient replicons preceding the last universal ancestor of cellular life.


2018 ◽  
Vol 15 (1) ◽  
Author(s):  
Chao Ye ◽  
Jiqiang Wu ◽  
Wu Tong ◽  
Tongling Shan ◽  
Xuefei Cheng ◽  
...  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Simin Chai ◽  
Ran Tian ◽  
Juanjuan Bi ◽  
Shixia Xu ◽  
Guang Yang ◽  
...  

Abstract Background The mammalian testis is an important male exocrine gland and spermatozoa-producing organ that usually lies in extra-abdominal scrotums to provide a cooler environment for spermatogenesis and sperm storage. Testicles sometimes fail to descend, leading to cryptorchidism. However, certain groups of mammals possess inherently ascrotal testes (i.e. testes that do not descend completely or at all) that have the same physiological functions as completely descended scrotal testes. Although several anatomical and hormonal factors involved in testicular descent have been studied, there is still a paucity of comprehensive research on the genetic mechanisms underlying the evolution of testicular descent in mammals and how mammals with ascrotal testes maintain their reproductive health. Results We performed integrative phenotypic and comparative genomic analyses of 380 cryptorchidism-related genes and found that the mammalian ascrotal testes trait is derived from an ancestral scrotal state. Rapidly evolving genes in ascrotal mammals were enriched in the Hedgehog pathway—which regulates Leydig cell differentiation and testosterone secretion—and muscle development. Moreover, some cryptorchidism-related genes in ascrotal mammals had undergone positive selection and contained specific mutations and indels. Genes harboring convergent/parallel amino acid substitutions between ascrotal mammals were enriched in GTPase functions. Conclusions Our results suggest that the scrotal testis is an ancestral state in mammals, and the ascrotal phenotype was derived multiple times in independent lineages. In addition, the adaptive evolution of genes involved in testicular descent and the development of the gubernaculum contributed to the evolution of ascrotal testes. Accurate DNA replication, the proper segregation of genetic material, and appropriate autophagy are the potential mechanisms for maintaining physiological normality during spermatogenesis in ascrotal mammals. Furthermore, the molecular convergence of GTPases is probably a mechanism in the ascrotal testes of different mammals. This study provides novel insights into the evolution of the testis and scrotum in mammals and contributes to a better understanding of the pathogenesis of cryptorchidism in humans.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3162 ◽  
Author(s):  
Ana Gutiérrez-Preciado ◽  
Carlos Vargas-Chávez ◽  
Mariana Reyes-Prieto ◽  
Omar F. Ordoñez ◽  
Diego Santos-García ◽  
...  

We report the genome sequence ofExiguobacterium chiriqhuchastr. N139, isolated from a high-altitude Andean lake. Comparative genomic analyses of theExiguobacteriumgenomes available suggest that our strain belongs to the same species as the previously reportedE. pavilionensisstr. RW-2 andExiguobacteriumstr. GIC 31. We describe this species and propose thechiriqhuchaname to group them. ‘Chiri qhucha’ in Quechua means ‘cold lake’, which is a common origin of these three cosmopolitan Exiguobacteria. The 2,952,588-bpE. chiriqhuchastr. N139 genome contains one chromosome and three megaplasmids. The genome analysis of the Andean strain suggests the presence of enzymes that conferE. chiriqhuchastr. N139 the ability to grow under multiple environmental extreme conditions, including high concentrations of different metals, high ultraviolet B radiation, scavenging for phosphorous and coping with high salinity. Moreover, the regulation of its tryptophan biosynthesis suggests that novel pathways remain to be discovered, and that these pathways might be fundamental in the amino acid metabolism of the microbial community from Laguna Negra, Argentina.


Sign in / Sign up

Export Citation Format

Share Document