scholarly journals Novel Integrative Elements and Genomic Plasticity in Ocean Ecosystems

2021 ◽  
Author(s):  
Thomas Hackl ◽  
Raphaël Laurenceau ◽  
Markus J. Ankenbrand ◽  
Christina Bliem ◽  
Zev Cariani ◽  
...  
Keyword(s):  
Genomic Plasticity ◽  
Ocean Ecosystems

Genomic plasticity and antibody response of Bordetella bronchiseptica strain HT200, a natural variant from a thermal spring

2021 ◽  
Vol 368 (6) ◽  
Author(s):  
Jhasketan Badhai ◽  
Subrata K Das
Keyword(s):  
Antibody Response ◽  
Virulence Factors ◽  
Thermal Spring ◽  
Asymptomatic Infection ◽  
Bordetella Bronchiseptica ◽  
Divergent Evolution ◽  
Environmental Niche ◽  
Genomic Plasticity ◽  
Genes Encoding ◽  
Natural Variant

ABSTRACT Classical Bordetella species are primarily isolated from animals and humans causing asymptomatic infection to lethal pneumonia. However, isolation of these bacteria from any extra-host environmental niche has not been reported so far. Here, we have characterized the genomic plasticity and antibody response of Bordetella bronchiseptica strain HT200, isolated from a thermal spring. Genomic ANI value and SNPs-based phylogenetic tree suggest a divergent evolution of strain HT200 from a human-adapted lineage of B. bronchiseptica. Growth and survivability assay showed strain HT200 retained viability for more than 5 weeks in the filter-sterilized spring water. In addition, genes or loci encoding the Bordetella virulence factors such as DNT, ACT and LPS O-antigen were absent in strain HT200, while genes encoding other virulence factors were highly divergent. Phenotypically, strain HT200 was non-hemolytic and showed weak hemagglutination activity, but was able to colonize in the respiratory organs of mice. Further, both infection and vaccination with strain HT200 induced protective antibody response in mouse against challenge infection with virulent B. bronchiseptica strain RB50. In addition, genome of strain HT200 (DSM 26023) showed presence of accessory genes and operons encoding predicted metabolic functions pertinent to the ecological conditions of the thermal spring.

scholarly journals BOX Elements Modulate Gene Expression in Streptococcus pneumoniae: Impact on the Fine-Tuning of Competence Development

2006 ◽  
Vol 188 (23) ◽  
pp. 8307-8312 ◽  
Author(s):  
Eivind Knutsen ◽  
Ola Johnsborg ◽  
Yves Quentin ◽  
Jean-Pierre Claverys ◽  
Leiv Sigve Håvarstein
Keyword(s):  
Gene Expression ◽  
Genetic Diversity ◽  
Streptococcus Pneumoniae ◽  
Competence Development ◽  
Fine Tuning ◽  
Present Evidence ◽  
Genomic Plasticity ◽  
Affect Expression ◽  
Intergenic Regions

ABSTRACT More than 100 BOX elements are randomly distributed in intergenic regions of the pneumococcal genome. Here we demonstrate that these elements can affect expression of neighboring genes and present evidence that they are mobile. Together, our findings show that BOX elements enhance genetic diversity and genomic plasticity in Streptococcus pneumoniae.

scholarly journals Giant African snail genomes provide insights into molluscan whole-genome duplication and aquatic-terrestrial transition

2020 ◽  
Author(s):  
Conghui Liu ◽  
Yuwei Ren ◽  
Zaiyuan Li ◽  
Qi Hu ◽  
Lijuan Yin ◽  
...  
Keyword(s):  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Terrestrial Ecosystems ◽  
Gene Families ◽  
Gene Clusters ◽  
Immune Defense ◽  
Whole Genome ◽  
Genomic Plasticity ◽  
Ecological Adaptability ◽  
Chromosome Level

AbstractWhole-genome duplication (WGD) has been observed across a wide variety of eukaryotic groups, contributing to evolutionary diversity and environmental adaptability. Mollusks are the second largest group of animals, and are among the organisms that have successfully adapted to the nonmarine realm through aquatic-terrestrial (A-T) transition, and no comprehensive research on WGD has been reported in this group. To explore WGD and the A-T transition in Mollusca, we assembled a chromosome-level reference genome for the giant African snail Achatina immaculata, a global invasive species, and compared the genomes of two giant African snails (A. immaculata and Achatina fulica) to the other available mollusk genomes. The chromosome-level macrosynteny, colinearity blocks, Ks peak and Hox gene clusters collectively suggested the occurrence of a WGD event shared by A. immaculata and A. fulica. The estimated timing of this WGD event (∼70 MYA) was close to the speciation age of the Sigmurethra-Orthurethra (within Stylommatophora) lineage and the Cretaceous-Tertiary (K-T) mass extinction, indicating that the WGD reported herein may have been a common event shared by all Sigmurethra-Orthurethra species and could have conferred ecological adaptability and genomic plasticity allowing the survival of the K-T extinction. Based on macrosynteny, we deduced an ancestral karyotype containing 8 conserved clusters for the Gastropoda-Bivalvia lineage. To reveal the mechanism of WGD in shaping adaptability to terrestrial ecosystems, we investigated gene families related to the respiration, aestivation and immune defense of giant African snails. Several mucus-related gene families expanded early in the Stylommatophora lineage, functioning in water retention, immune defense and wound healing. The hemocyanins, PCK and FBP families were doubled and retained after WGD, enhancing the capacity for gas exchange and glucose homeostasis in aestivation. After the WGD, zinc metalloproteinase genes were highly tandemly duplicated to protect tissue against ROS damage. This evidence collectively suggests that although the WGD may not have been the direct driver of the A-T transition, it provided an important legacy for the terrestrial adaptation of the giant African snail.

scholarly journals Tripartite holobiont system in a vent snail broadens the concept of chemosymbiosis

2020 ◽  
Author(s):  
Yi Yang ◽  
Jin Sun ◽  
Chong Chen ◽  
Yadong Zhou ◽  
Yi Lan ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Deep Sea ◽  
Extreme Environments ◽  
Host Immunity ◽  
Energy Sources ◽  
High Quality ◽  
Genomic Plasticity ◽  
Changing Environments ◽  
Metabolic Heterogeneity ◽  
Genomic Basis

AbstractMany animals inhabiting deep-sea vents are energetically dependent on chemosynthetic endosymbionts, but how such symbiont community interacts with host, and whether other nutritional sources are available to such animals remain unclear. To reveal the genomic basis of symbiosis in the vent snail Alviniconcha marisindica, we sequenced high-quality genomes of the host and gill campylobacterial endosymbionts, as well as metagenome of the gut microbiome. The gill endosymbiont has a streamlined genome for efficient chemoautotrophy, but also shows metabolic heterogeneity among populations. Inter- and intra-host variabilities among endosymbiont populations indicate the host poses low selection on gill endosymbionts. Virulence factors and genomic plasticity of the endosymbiont provide advantages for cooperating with host immunity to maintain mutualism and thriving in changing environments. In addition to endosymbiosis, the gut and its microbiome expand the holobiont’s utilisation of energy sources. Host-microbiota mutualism contributes to a highly flexible holobiont that can excel in various extreme environments.

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