scholarly journals The Two TpsB-like Proteins in Anabaena sp. PCC 7120 Are Involved in Secretion of Selected Substrates.

2020 ◽  
Author(s):  
Giang Ngo ◽  
Melis Girbas ◽  
Hannah Schätzle ◽  
Andreas Hammer ◽  
Schara Safarian ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Pathogenic Bacteria ◽  
Carbon Fixation ◽  
Membrane Integrity ◽  
Genomic Region ◽  
Secretion System ◽  
Secretion Systems ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Pcc 7120

The outer membrane of Gram-negative bacteria acts as an initial diffusion barrier that shields the cell from the environment. It contains many membrane-embedded proteins required for functionality of this system. These proteins serve as solute and lipid transporters or as machines for membrane insertion or secretion of proteins. The genome of Anabaena sp. PCC 7120 codes for two outer membrane transporters termed TpsB1 and TpsB2. Those belong to the family of the two-partner secretion system proteins which are characteristic for pathogenic bacteria. Because pathogenicity of Anabaena sp. PCC 7120 has not been reported, the function of these two cyanobacterial TpsB proteins was analyzed. TpsB1 is encoded by alr1659, while TpsB2 is encoded by all5116. The latter is part of a genomic region containing 11 genes encoding TpsA-like proteins. However, tpsB2 is transcribed independently of a tpsA gene-cluster. Bioinformatics analysis revealed the presence of at least 22 genes in Anabaena sp. PCC 7120 putatively coding for substrates of the TpsB-system suggesting a rather global function of the two TpsB proteins. Insertion of a plasmid into each of the two genes, respectively, resulted in phenotypes of altered outer membrane integrity and antibiotic resistance. In addition, the expression of genes coding for the Clp and Deg proteases is dysregulated in these mutants. Moreover, for two of the putative substrates a dependence of the secretion on functional TpsB proteins could be confirmed. We confirm the existence of a two-partner secretion system in Anabaena sp. PCC 7120 and predict a large pool of putative substrates. IMPORTANCE Cyanobacteria are important organisms for the ecosystem considering their contribution to carbon fixation and oxygen production, while at the same time some species produce compounds that are toxic to their environment. As a consequence, cyanobacteria overpopulation might negatively impact the diversity of natural communities. Thus, a detailed understanding of cyanobacterial interaction with the environment including other organisms is required to define their impact on ecosystems. While two-partner secretion systems are well known from pathogenic bacteria, we provide a first description of the cyanobacterial two-partner secretion system.

scholarly journals The Francisella Pathogenicity Island Protein PdpD Is Required for Full Virulence and Associates with Homologues of the Type VI Secretion System

2008 ◽  
Vol 190 (13) ◽  
pp. 4584-4595 ◽  
Author(s):  
Jagjit S. Ludu ◽  
Olle M. de Bruin ◽  
Barry N. Duplantis ◽  
Crystal L. Schmerk ◽  
Alicia Y. Chou ◽  
...  
Keyword(s):  
North America ◽  
Outer Membrane ◽  
Bacterial Pathogen ◽  
Pathogenicity Island ◽  
Secretion System ◽  
Type Vi Secretion System ◽  
Secretion Systems ◽  
Intracellular Growth ◽  
Type Vi Secretion ◽  
Genes Encoding

ABSTRACT Francisella tularensis is a highly infectious, facultative intracellular bacterial pathogen that is the causative agent of tularemia. Nearly a century ago, researchers observed that tularemia was often fatal in North America but almost never fatal in Europe and Asia. The chromosomes of F. tularensis strains carry two identical copies of the Francisella pathogenicity island (FPI), and the FPIs of North America-specific biotypes contain two genes, anmK and pdpD, that are not found in biotypes that are distributed over the entire Northern Hemisphere. In this work, we studied the contribution of anmK and pdpD to virulence by using F. novicida, which is very closely related to F. tularensis but which carries only one copy of the FPI. We showed that anmK and pdpD are necessary for full virulence but not for intracellular growth. This is in sharp contrast to most other FPI genes that have been studied to date, which are required for intracellular growth. We also showed that PdpD is localized to the outer membrane. Further, overexpression of PdpD affects the cellular distribution of FPI-encoded proteins IglA, IglB, and IglC. Finally, deletions of FPI genes encoding proteins that are homologues of known components of type VI secretion systems abolished the altered distribution of IglC and the outer membrane localization of PdpD.

EST mining for structure and expression of genes in the region of the wheat high-molecular-weight glutenin loci

Genome ◽  
2009 ◽  
Vol 52 (8) ◽  
pp. 726-740 ◽  
Author(s):  
O. D. Anderson
Keyword(s):  
Expressed Sequence Tags ◽  
Genomic Region ◽  
Chromatin Domain ◽  
Gene Sequences ◽  
Orthologous Genes ◽  
Coding Regions ◽  
Expression Of Genes ◽  
Depth Analysis ◽  
Genes Encoding ◽  
Expressed Sequence

An in-depth analysis was carried out with expressed sequence tags (ESTs) for genes in and near the HMW-GS loci. Considerations for using ESTs are discussed, including the occurrence of chimeric and aberrant HMW-GS ESTs. Complete gene sequences demonstrated the feasibility of constructing accurate full-length coding regions from EST assemblies and found, or supported, errors in several previously reported HMW-GS gene sequences. New complete HMW-GS gene sequences are reported for the cultivars Chinese Spring and Glenlea. The Ay subunit gene, which is considered null in cultivated wheats, was shown to transcribe in at least two germplasms. Analyses support the conclusion that of the five known genes within this genomic region, the two HMW-GS genes and the globulin gene are highly expressed. The other two genes, encoding a receptor kinase and a protein kinase, have one and no identifiable wheat EST, respectively, although ESTs are found for the orthologous genes in barley. The ESTs of all five genes within the HMW-GS region are either definitely associated with the endosperm or possibly originate from imbibed seed, suggesting the four distinct gene classes in this region are part of a seed or endosperm chromatin domain. EST resources were also used to determine relative abundance of ESTs for all classes of wheat prolamines and indicated differential levels of expression both among germplasms and among the three genomes of hexaploid wheats.

scholarly journals Chlamydial Type III Secretion System Is Encoded on Ten Operons Preceded by Sigma 70-Like Promoter Elements

2006 ◽  
Vol 189 (1) ◽  
pp. 198-206 ◽  
Author(s):  
P. Scott Hefty ◽  
Richard S. Stephens
Keyword(s):  
Type Iii Secretion ◽  
Transcriptional Start Site ◽  
Type Iii Secretion System ◽  
Regulatory Elements ◽  
Secretion System ◽  
Secretion Systems ◽  
Promoter Elements ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Genes Encoding

ABSTRACT Many gram-negative bacterial pathogens employ type III secretion systems for infectious processes. Chlamydiae are obligate intracellular bacteria that encode a conserved type III secretion system that is likely requisite for growth. Typically, genes encoding type III secretion systems are located in a single locus; however, for chlamydiae these genes are scattered throughout the genome. Little is known regarding the gene regulatory mechanisms for this essential virulence determinant. To facilitate identification of cis-acting transcriptional regulatory elements, the operon structure was determined. This analysis revealed 10 operons that contained 37 genes associated with the type III secretion system. Linkage within these operons suggests a role in type III secretion for each of these genes, including 13 genes encoding proteins with unknown function. The transcriptional start site for each operon was determined. In conjunction with promoter activity assays, this analysis revealed that the type III secretion system operons encode σ70-like promoter elements. Transcriptional initiation by a sigma factor responsible for constitutive gene expression indicates that undefined activators or repressors regulate developmental stage-specific expression of chlamydial type III secretion system genes.

scholarly journals Mutations in Salmonella Pathogenicity Island 2 (SPI2) Genes Affecting Transcription of SPI1 Genes and Resistance to Antimicrobial Agents

1998 ◽  
Vol 180 (18) ◽  
pp. 4775-4780 ◽  
Author(s):  
Jörg Deiwick ◽  
Thomas Nikolaus ◽  
Jaqueline E. Shea ◽  
Colin Gleeson ◽  
David W. Holden ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Antimicrobial Agents ◽  
Type Iii Secretion System ◽  
Polymyxin B ◽  
Secretion System ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Type Iii ◽  
Genes Encoding

ABSTRACT The Salmonella typhimurium genome contains two pathogenicity islands (SPI) with genes encoding type III secretion systems for virulence proteins. SPI1 is required for the penetration of the epithelial layer of the intestine. SPI2 is important for the subsequent proliferation of bacteria in the spleens of infected hosts. Although most mutations in SPI2 lead to a strong reduction of virulence, they have different effects in vitro, with some mutants having significantly increased sensitivity to gentamicin and the antibacterial peptide polymyxin B. Previously we showed that certain mutations in SPI2 affect the ability of S. typhimurium to secrete SPI1 effector proteins and to invade cultured eukaryotic cells. In this study, we show that these SPI2 mutations affect the expression of the SPI1 invasion genes. Analysis of reporter fusions to various SPI1 genes reveals highly reduced expression of sipC,prgK, and hilA, the transcriptional activator of SPI1 genes. These observations indicate that the expression of one type III secretion system can be influenced dramatically by mutations in genes encoding a second type III secretion system in the same cell.

scholarly journals Relation between Biofilm and Virulence in Vibrio tapetis: A Transcriptomic Study

Pathogens ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 92 ◽  
Author(s):  
Sophie Rodrigues ◽  
Christine Paillard ◽  
Sabine Van Dillen ◽  
Ali Tahrioui ◽  
Jean-Marc Berjeaud ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Cell System ◽  
Ruditapes Philippinarum ◽  
Differentially Expressed ◽  
Type Vi Secretion System ◽  
Altered Expression ◽  
Expression Of Genes ◽  
Polysaccharide Synthesis ◽  
Genes Encoding ◽  
Genetic Level

Marine pathogenic bacteria are able to form biofilms on many surfaces, such as mollusc shells, and they can wait for the appropriate opportunity to induce their virulence. Vibrio tapetis can develop such biofilms on the inner surface of shells of the Ruditapes philippinarum clam, leading to the formation of a brown conchiolin deposit in the form of a ring, hence the name of the disease: Brown Ring Disease. The virulence of V. tapetis is presumed to be related to its capacity to form biofilms, but the link has never been clearly established at the physiological or genetic level. In the present study, we used RNA-seq analysis to identify biofilm- and virulence-related genes displaying altered expression in biofilms compared to the planktonic condition. A flow cell system was employed to grow biofilms to obtain both structural and transcriptomic views of the biofilms. We found that 3615 genes were differentially expressed, confirming that biofilm and planktonic lifestyles are very different. As expected, the differentially expressed genes included those involved in biofilm formation, such as motility- and polysaccharide synthesis-related genes. The data show that quorum sensing is probably mediated by the AI-2/LuxO system in V. tapetis biofilms. The expression of genes encoding the Type VI Secretion System and associated exported proteins are strongly induced, suggesting that V. tapetis activates this virulence factor when living in biofilm.

scholarly journals WhiB5, a Transcriptional Regulator That Contributes to Mycobacterium tuberculosis Virulence and Reactivation

2012 ◽  
Vol 80 (9) ◽  
pp. 3132-3144 ◽  
Author(s):  
Stefano Casonato ◽  
Axel Cervantes Sánchez ◽  
Hirohito Haruki ◽  
Monica Rengifo González ◽  
Roberta Provvedi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Chronic Infection ◽  
Null Mutant ◽  
Wild Type ◽  
Secretion Systems ◽  
Content Type ◽  
Type Vii Secretion ◽  
Expression Of Genes ◽  
Genes Encoding

ABSTRACTThe proteins belonging to the WhiB superfamily are small global transcriptional regulators typical of actinomycetes. In this paper, we characterize the role of WhiB5, aMycobacterium tuberculosisprotein belonging to this superfamily. A null mutant was constructed inM. tuberculosisH37Rv and was shown to be attenuated during both progressive and chronic mouse infections. Mice infected with the mutant had smaller bacillary burdens in the lungs but a larger inflammatory response, suggesting a role of WhiB5 in immunomodulation. Most interestingly, thewhiB5mutant was not able to resume growth after reactivation from chronic infection, suggesting that WhiB5 controls the expression of genes involved in this process. The mutant was also more sensitive than the wild-type parental strain toS-nitrosoglutathione (GSNO) and was less metabolically active following prolonged starvation, underscoring the importance of GSNO and starvation in development and maintenance of chronic infection. DNA microarray analysis identified 58 genes whose expression is influenced by WhiB5, includingsigM, encoding an alternative sigma factor, and genes encoding the constituents of two type VII secretion systems, namely, ESX-2 and ESX-4.

scholarly journals Protein Transfer through an F Plasmid-Encoded Type IV Secretion System Suppresses the Mating-Induced SOS Response

mBio ◽  
2021 ◽  
Author(s):  
Abu Amar M. Al Mamun ◽  
Kouhei Kishida ◽  
Peter J. Christie
Keyword(s):  
Heavy Metals ◽  
Sos Response ◽  
Secretion System ◽  
Type Iv Secretion ◽  
Type Iv Secretion System ◽  
Conjugative Transfer ◽  
Secretion Systems ◽  
Protein Transfer ◽  
Type Iv ◽  
Genes Encoding

Many bacteria carry plasmids and other mobile genetic elements (MGEs) whose conjugative transfer through encoded type IV secretion systems (T4SSs), or “mating channels,” can lead to a rapid intra- and interspecies proliferation of genes encoding resistance to antibiotics or heavy metals or virulence traits. Here, we show that a model IncF plasmid-encoded T4SS translocates not only DNA but also several proteins intercellularly.

scholarly journals Alr0397 Is an Outer Membrane Transporter for the Siderophore Schizokinen in Anabaena sp. Strain PCC 7120

2008 ◽  
Vol 190 (22) ◽  
pp. 7500-7507 ◽  
Author(s):  
Kerstin Nicolaisen ◽  
Suncana Moslavac ◽  
Anastazia Samborski ◽  
Marianne Valdebenito ◽  
Klaus Hantke ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Iron Homeostasis ◽  
Iron Starvation ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Outer Membrane Transporter ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Outer Membrane Transporters

ABSTRACT Iron uptake in proteobacteria by TonB-dependent outer membrane transporters represents a well-explored subject. In contrast, the same process has been scarcely investigated in cyanobacteria. The heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 is known to secrete the siderophore schizokinen, but its transport system has remained unidentified. Inspection of the genome of strain PCC 7120 shows that only one gene encoding a putative TonB-dependent iron transporter, namely alr0397, is positioned close to genes encoding enzymes involved in the biosynthesis of a hydroxamate siderophore. The expression of alr0397, which encodes an outer membrane protein, was elevated under iron-limited conditions. Inactivation of this gene caused a moderate phenotype of iron starvation in the mutant cells. The characterization of the mutant strain showed that Alr0397 is a TonB-dependent schizokinen transporter (SchT) of the outer membrane and that alr0397 expression and schizokinen production are regulated by the iron homeostasis of the cell.

scholarly journals YghG (GspSβ) Is a Novel Pilot Protein Required for Localization of the GspSβType II Secretion System Secretin of Enterotoxigenic Escherichia coli

2012 ◽  
Vol 80 (8) ◽  
pp. 2608-2622 ◽  
Author(s):  
Timothy G. Strozen ◽  
Gang Li ◽  
S. Peter Howard
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Secretion System ◽  
Enterotoxigenic Escherichia Coli ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Secretion Systems ◽  
Content Type ◽  
Insertional Inactivation ◽  
Prepilin Peptidase

ABSTRACTThe enterotoxigenicEscherichia coli(ETEC) pathotype, characterized by the prototypical strain H10407, is a leading cause of morbidity and mortality in the developing world. A major virulence factor of ETEC is the type II secretion system (T2SS) responsible for secretion of the diarrheagenic heat-labile enterotoxin (LT). In this study, we have characterized the two type II secretion systems, designated alpha (T2SSα) and beta (T2SSβ), encoded in the H10407 genome and describe the prevalence of both systems in otherE. colipathotypes. Under laboratory conditions, the T2SSβis assembled and functional in the secretion of LT into culture supernatant, whereas the T2SSαis not. Insertional inactivation of the three genes located upstream ofgspCβ(yghJ,pppA, andyghG) in the atypical T2SSβoperon revealed that YghJ is not required for assembly of the GspDβsecretin or secretion of LT, that PppA is likely the prepilin peptidase required for the function of T2SSβ, and that YghG is required for assembly of the GspDβsecretin and thus function of the T2SSβ. Mutational and physiological analysis further demonstrated that YghG (redesignated GspSβ) is a novel outer membrane pilotin protein that is integral for assembly of the T2SSβby localizing GspDβto the outer membrane, whereupon GspDβforms the macromolecular secretin multimer through which T2SSβsubstrates are translocated.

scholarly journals Modular evolution of secretion systems and virulence plasmids in a bacterial species complex

BMC Biology ◽  
2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Lin Chou ◽  
Yu-Chen Lin ◽  
Mindia Haryono ◽  
Mary Nia M. Santos ◽  
Shu-Ting Cho ◽  
...  
Keyword(s):  
Species Complex ◽  
Bacterial Species ◽  
Secretion System ◽  
Type Vi Secretion System ◽  
Secretion Systems ◽  
Bacterial Taxonomy ◽  
Plant Host ◽  
Modular Evolution ◽  
Species Complexes ◽  
Genes Encoding

Abstract Background Many named species as defined in current bacterial taxonomy correspond to species complexes. Uncertainties regarding the organization of their genetic diversity challenge research efforts. We utilized the Agrobacterium tumefaciens species complex (a.k.a. Agrobacterium biovar 1), a taxon known for its phytopathogenicity and applications in transformation, as a study system and devised strategies for investigating genome diversity and evolution of species complexes. Results We utilized 35 genome assemblies, including 14 newly generated ones, to achieve a phylogenetically balanced sampling of A. tumefaciens. Our genomic analysis suggested that the 10 genomospecies described previously are distinct biological species and supported a quantitative guideline for species delineation. Furthermore, our inference of gene content and core-genome phylogeny allowed for investigations of genes critical in fitness and ecology. For the type VI secretion system (T6SS) involved in interbacterial competition and thought to be conserved, we detected multiple losses and one horizontal gene transfer. For the tumor-inducing plasmids (pTi) and pTi-encoded type IV secretion system (T4SS) that are essential for agrobacterial phytopathogenicity, we uncovered novel diversity and hypothesized their involvement in shaping this species complex. Intriguingly, for both T6SS and T4SS, genes encoding structural components are highly conserved, whereas extensive diversity exists for genes encoding effectors and other proteins. Conclusions We demonstrate that the combination of a phylogeny-guided sampling scheme and an emphasis on high-quality assemblies provides a cost-effective approach for robust analysis in evolutionary genomics. We show that the T6SS VgrG proteins involved in specific effector binding and delivery can be classified into distinct types based on domain organization. The co-occurrence patterns of VgrG-associated domains and the neighboring genes that encode different chaperones/effectors can be used to infer possible interacting partners. Similarly, the associations between plant host preference and the pTi type among these strains can be used to infer phenotype-genotype correspondence. Our strategies for multi-level investigations at scales that range from whole genomes to intragenic domains and phylogenetic depths from between- to within-species are applicable to other bacteria. Furthermore, modularity observed in the molecular evolution of genes and domains is useful for inferring functional constraints and informing experimental works.

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