scholarly journals RNA polymerases from Low G+C Gram Positive Bacteria

2021 ◽  
Author(s):  
Michael Miller ◽  
Aaron Oakley ◽  
Peter Lewis
Keyword(s):  
Gene Expression ◽  
Structural Information ◽  
Gram Positive ◽  
Control Of Gene Expression ◽  
Gram Negative ◽  
Auxiliary Subunits ◽  
Gram Positive Bacteria ◽  
High Resolution Structure ◽  
Resolution Structure

The low G+C Gram positive bacteria represent some of the most medically and industrially important microorganisms. They are relied on for the production of food and dietary supplements, enzymes and antibiotics, as well as being responsible for the majority of nosocomial infections and serving as a reservoir for antibiotic resistance. Control of gene expression in this group is more highly studied than in any bacteria other than the Gram negative model Escherichia coli, yet until recently no structural information on RNA polymerase (RNAP) from this group was available. This review will summarise recent reports on the high resolution structure of RNAP from the model low G+C representative Bacillus subtilis, including the role of auxiliary subunits δ and ε, and outline approaches for the development of antimicrobials to target RNAP from this group.

scholarly journals The Recombination Genes addAB Are Not Restricted to Gram-Positive Bacteria: Genetic Analysis of the Recombination Initiation Enzymes RecF and AddAB in Rhizobium etli

2004 ◽  
Vol 186 (23) ◽  
pp. 7905-7913 ◽  
Author(s):  
Jacobo Zuñiga-Castillo ◽  
David Romero ◽  
Jaime M. Martínez-Salazar
Keyword(s):  
Recombination Frequency ◽  
Double Strand Breaks ◽  
Additive Effect ◽  
Gram Negative Bacteria ◽  
Rhizobium Etli ◽  
Gram Positive ◽  
Gram Negative ◽  
Strand Breaks ◽  
Gram Positive Bacteria

ABSTRACT Single-strand gaps (SSGs) and double-strand breaks (DSBs) are the major initiation sites for recombination. In bacteria, the SSGs are repaired by RecFOR, while the DSBs are processed by RecBCD in gram-negative bacteria and AddAB in gram-positive bacteria. Unexpectedly, instead of recBCD genes, the addAB genes were found in members of the α-proteobacteria group (gram negative). Taking Rhizobium etli as a model, the role of recF and addAB genes in homologous recombination and repair of damaged DNA was evaluated. Inactivation of either recF or addA provoked strong sensitivity to UV radiation and mitomycin C, while an additive effect was observed in the recF-addA mutant. The DSBs generated by nalidixic acid caused low viability only in the addA mutant. The recombination frequency of large and small plasmids was reduced in the recF mutant (24- and 36-fold, respectively), whereas a slight decrease (threefold) in the addA mutant was observed. Moreover, an additive effect (47- and 90-fold, respectively) was observed in the double mutant, but it was not as dramatic as that in a recA mutant. Interestingly, the frequency of deletion and Campbell-type recombination was slightly affected in either single or double mutants. These results suggest that another pathway exists that allows plasmid and Campbell-type recombination in the absence of recF and addA genes.

scholarly journals Lipoproteins of Gram-Positive Bacteria: Key Players in the Immune Response and Virulence

2016 ◽  
Vol 80 (3) ◽  
pp. 891-903 ◽  
Author(s):  
Minh Thu Nguyen ◽  
Friedrich Götz
Keyword(s):  
Immune Response ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Key Players ◽  
Toll Like Receptor 2 ◽  
Number Of Publications

SUMMARYSince the discovery in 1973 of the first of the bacterial lipoproteins (Lpp) inEscherichia coli, Braun's lipoprotein, the ever-increasing number of publications indicates the importance of these proteins. Bacterial Lpp belong to the class of lipid-anchored proteins that in Gram-negative bacteria are anchored in both the cytoplasmic and outer membranes and in Gram-positive bacteria are anchored only in the cytoplasmic membrane. In contrast to the case for Gram-negative bacteria, in Gram-positive bacteria lipoprotein maturation and processing are not vital. Physiologically, Lpp play an important role in nutrient and ion acquisition, allowing particularly pathogenic species to better survive in the host. Bacterial Lpp are recognized by Toll-like receptor 2 (TLR2) of the innate immune system. The important role of Lpp in Gram-positive bacteria, particularly in the phylumFirmicutes, as key players in the immune response and pathogenicity has emerged only in recent years. In this review, we address the role of Lpp in signaling and modulating the immune response, in inflammation, and in pathogenicity. We also address the potential of Lpp as promising vaccine candidates.

scholarly journals The Fst/Ldr Family of Type I TA System Toxins: Potential Roles in Stress Response, Metabolism and Pathogenesis

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 474
Author(s):  
Keith Weaver
Keyword(s):  
Sugar Metabolism ◽  
Type I ◽  
Gram Positive ◽  
Gram Negative ◽  
Over Expression ◽  
Gram Positive Bacteria ◽  
The Family ◽  
Peptide Toxins ◽  
And Function

The parpAD1 locus was the first type I toxin–antitoxin (TA) system described in Gram-positive bacteria and was later determined to be the founding member of a widely distributed family of plasmid- and chromosomally encoded TA systems. Indeed, homology searches revealed that the toxin component, FstpAD1, is a member of the Fst/Ldr superfamily of peptide toxins found in both Gram-positive and Gram-negative bacteria. Regulation of the Fst and Ldr toxins is distinct in their respective Gram-positive and Gram-negative hosts, but the effects of ectopic over-expression are similar. While, the plasmid versions of these systems appear to play the canonical role of post-segregational killing stability mechanisms, the function of the chromosomal systems remains largely obscure. At least one member of the family has been suggested to play a role in pathogenesis in Staphylococcus aureus, while the regulation of several others appear to be tightly integrated with genes involved in sugar metabolism. After a brief discussion of the regulation and function of the foundational parpAD1 locus, this review will focus on the current information available on potential roles of the chromosomal homologs.

scholarly journals Stenotrophomonas maltophilia D457R Contains a Cluster of Genes from Gram-Positive Bacteria Involved in Antibiotic and Heavy Metal Resistance

2000 ◽  
Vol 44 (7) ◽  
pp. 1778-1782 ◽  
Author(s):  
Ana Alonso ◽  
Patricia Sanchez ◽  
José L. Martínez
Keyword(s):  
Heavy Metal ◽  
Stenotrophomonas Maltophilia ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT A cluster of genes involved in antibiotic and heavy metal resistance has been characterized from a clinical isolate of the gram-negative bacterium Stenotrophomonas maltophilia. These genes include a macrolide phosphotransferase (mphBM) and a cadmium efflux determinant (cadA), together with the genecadC coding for its transcriptional regulator. ThecadC cadA region is flanked by a truncated IS257 sequence and a region coding for a bin3invertase. Despite their presence in a gram-negative bacterium, these genetic elements share a common gram-positive origin. The possible origin of these determinants as a remnant composite transposon as well as the role of gene transfer between gram-positive and gram-negative bacteria for the acquisition of antibiotic resistance determinants in chronic, mixed infections is discussed.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

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