scholarly journals Friends or Foes—Microbial Interactions in Nature

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 496
Author(s):  
Nancy Weiland-Bräuer

Microorganisms are present in nearly every niche on Earth and mainly do not exist solely but form communities of single or mixed species. Within such microbial populations and between the microbes and a eukaryotic host, various microbial interactions take place in an ever-changing environment. Those microbial interactions are crucial for a successful establishment and maintenance of a microbial population. The basic unit of interaction is the gene expression of each organism in this community in response to biotic or abiotic stimuli. Differential gene expression is responsible for producing exchangeable molecules involved in the interactions, ultimately leading to community behavior. Cooperative and competitive interactions within bacterial communities and between the associated bacteria and the host are the focus of this review, emphasizing microbial cell–cell communication (quorum sensing). Further, metagenomics is discussed as a helpful tool to analyze the complex genomic information of microbial communities and the functional role of different microbes within a community and to identify novel biomolecules for biotechnological applications.

2014 ◽  
Vol 82 (4) ◽  
pp. 1511-1522 ◽  
Author(s):  
Zhiming Ouyang ◽  
Jianli Zhou ◽  
Michael V. Norgard

ABSTRACTBorrelia burgdorferiencodes a homologue of the bacterial carbon storage regulator A (CsrA). Recently, it was reported that CsrA contributes toB. burgdorferiinfectivity and is required for the activation of the central RpoN-RpoS regulatory pathway. However, many questions concerning the function of CsrA inB. burgdorferigene regulation remain unanswered. In particular, there are conflicting reports concerning the molecular details of how CsrA may modulaterpoSexpression and, thus, how CsrA may influence the RpoN-RpoS pathway inB. burgdorferi. To address these key discrepancies, we examined the role of CsrA in differential gene expression in the Lyme disease spirochete. Upon engineering an induciblecsrAexpression system inB. burgdorferi, controlled hyperexpression of CsrA in a merodiploid strain did not significantly alter the protein and transcript levels ofbosR,rpoS, and RpoS-dependent genes (such asospCanddbpA). In addition, we constructed isogeniccsrAmutants in two widely used infectiousB. burgdorferistrains. When expression ofbosR,rpoS,ospC, anddbpAwas compared between thecsrAmutants and their wild-type counterparts, no detectable differences were observed. Finally, animal studies indicated that thecsrAmutants remained infectious for and virulent in mice. Analyses ofB. burgdorferigene expression in mouse tissues showed comparable levels ofrpoStranscripts by thecsrAmutants and the parental strains. Taken together, these results constitute compelling evidence that CsrA is not involved in activation of the RpoN-RpoS pathway and is dispensable for mammalian infectious processes carried out byB. burgdorferi.


Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 137 ◽  
Author(s):  
Shenglin Liu ◽  
Anne Aagaard ◽  
Jesper Bechsgaard ◽  
Trine Bilde

Variation in DNA methylation patterns among genes, individuals, and populations appears to be highly variable among taxa, but our understanding of the functional significance of this variation is still incomplete. We here present the first whole genome bisulfite sequencing of a chelicerate species, the social spider Stegodyphus dumicola. We show that DNA methylation occurs mainly in CpG context and is concentrated in genes. This is a pattern also documented in other invertebrates. We present RNA sequence data to investigate the role of DNA methylation in gene regulation and show that, within individuals, methylated genes are more expressed than genes that are not methylated and that methylated genes are more stably expressed across individuals than unmethylated genes. Although no causal association is shown, this lends support for the implication of DNA CpG methylation in regulating gene expression in invertebrates. Differential DNA methylation between populations showed a small but significant correlation with differential gene expression. This is consistent with a possible role of DNA methylation in local adaptation. Based on indirect inference of the presence and pattern of DNA methylation in chelicerate species whose genomes have been sequenced, we performed a comparative phylogenetic analysis. We found strong evidence for exon DNA methylation in the horseshoe crab Limulus polyphemus and in all spider and scorpion species, while most Parasitiformes and Acariformes species seem to have lost DNA methylation.


2007 ◽  
Vol 97 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Leland S. Pierson ◽  
Elizabeth A. Pierson

In nature, Pseudomonas species compete and co-exist in mixed communities with a diversity of prokaryotic and eukaryotic micro- and macroorganisms. Many bacteria produce various signals that control gene expression and thus contribute to specific bacterial behaviors and coordinate essential functions with other members of the community. The best-studied signaling compounds are N-acyl-homoserine lactones (AHLs), which are involved in quorum sensing (QS) regulation and are produced by a diverse range of bacterial taxa. To date, research on QS has focused on how signals control gene expression in the bacterial cell and the role of these signals in positive and negative communication among different groups of organisms. Additionally, mechanisms for AHL decay and AHL utilization as sole carbon/energy sources have been identified. Some host organisms produce compounds that can mimic AHLs, and some bacterial signals can influence host gene expression. Thus, interkingdom communication may be more widespread than previously believed. Our current understanding of individual, community and bacterial-host interactions is still in its infancy and there are many exciting discoveries yet to be made.


2001 ◽  
Vol 94 (5) ◽  
pp. 674-684 ◽  
Author(s):  
Boris P.-L. Lee ◽  
Walter J. Rushlow ◽  
Chandan Chakraborty ◽  
Peeyush K. Lala

2016 ◽  
Vol 12 (3) ◽  
pp. 20160069 ◽  
Author(s):  
Adam M. Fudickar ◽  
Mark P. Peterson ◽  
Timothy J. Greives ◽  
Jonathan W. Atwell ◽  
Eli S. Bridge ◽  
...  

In an era of climate change, understanding the genetic and physiological mechanisms underlying flexibility in phenology and life history has gained greater importance. These mechanisms can be elucidated by comparing closely related populations that differ in key behavioural and physiological traits such as migration and timing of reproduction. We compared gene expression in two recently diverged dark-eyed Junco (  Junco hyemalis ) subspecies that live in seasonal sympatry during winter and early spring, but that differ in behaviour and physiology, despite exposure to identical environmental cues. We identified 547 genes differentially expressed in blood and pectoral muscle. Genes involved in lipid transport and metabolism were highly expressed in migrant juncos, while genes involved in reproductive processes were highly expressed in resident breeders. Seasonal differences in gene expression in closely related populations residing in the same environment provide significant insights into mechanisms underlying variation in phenology and life history, and have potential implications for the role of seasonal timing differences in gene flow and reproductive isolation.


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