scholarly journals Changes in the expression of genes encoding type IV pili-associated proteins are seen when Clostridium perfringens is grown in liquid or on surfaces

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Samantha R. Soncini ◽  
Andrea H. Hartman ◽  
Tara M. Gallagher ◽  
Gary J. Camper ◽  
Roderick V. Jensen ◽  
...  
Keyword(s):  
Clostridium Perfringens ◽  
Type Iv Pili ◽  
Type Iv ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Associated Proteins

scholarly journals Characterization of type IV pili in the life cycle of the predator bacterium Bdellovibrio

Microbiology ◽  
2010 ◽  
Vol 156 (4) ◽  
pp. 1040-1051 ◽  
Author(s):  
Khaled K. Mahmoud ◽  
Susan F. Koval
Keyword(s):  
Life Cycle ◽  
Insoluble Fraction ◽  
Type Iv Pili ◽  
Host Cells ◽  
Prey Cell ◽  
Gram Negative ◽  
Type Iv ◽  
Genes Encoding ◽  
Attack Phase

Bdellovibrio and like organisms (BALOs) are obligate prokaryotic predators of other Gram-negative bacteria. Bdellovibrio bacteriovorus is the most studied organism among BALOs. It has a periplasmic life cycle with two major stages: a motile, non-replicative stage spent searching for prey (the attack phase) and a stage spent inside the periplasm of the Gram-negative prey cell (the growth phase) after forming an osmotically stable body termed the bdelloplast. Within Bdellovibrio, there are also strains exhibiting an epibiotic life cycle. The genome sequence of the type strain B. bacteriovorus HD100T revealed the presence of multiple dispersed pil genes encoding type IV pili. Type IV pili in other bacteria are involved in adherence to and invasion of host cells and therefore can be considered to play a role in invasion of prey cells by Bdellovibrio. In this study, genes involved in producing type IV pili were identified in the periplasmic strain B. bacteriovorus 109J and an epibiotic Bdellovibrio sp. strain JSS. The presence of fibres on attack-phase cells was confirmed by examining negative stains of cells fixed with 10 % buffered formalin. Fibres were at the non-flagellated pole on approximately 25 % of attack-phase cells. To confirm that these fibres were type IV pili, a truncated form of PilA lacking the first 35 amino acids was designed to facilitate purification of the protein. The truncated PilA fused to a His-tag was overexpressed in Escherichia coli BL21(DE3) plysS. The fusion protein, accumulated in the insoluble fraction, was purified under denaturing conditions and used to produce polyclonal antisera. Immunoelectron microscopy showed that polar fibres present on the cell surface of the predator were composed of PilA, the major subunit of type IV pili. Immunofluorescence microscopy showed the presence of pilin on attack-phase cells of B. bacteriovorus 109J during attachment to prey cells and just after penetration, inside the bdelloplast. Antibodies against PilA delayed and inhibited predation in co-cultures of Bdellovibrio. This study confirms that type IV pili play a role in invasion of prey cells by Bdellovibrio.

scholarly journals Sequence analysis and confirmation of the type IV pili-associated proteins PilY1, PilW and PilV in Acidithiobacillus thiooxidans

PLoS ONE ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. e0199854
Author(s):  
Elvia Alfaro-Saldaña ◽  
Araceli Hernández-Sánchez ◽  
O. Araceli Patrón-Soberano ◽  
Marizel Astello-García ◽  
J. Alfredo Méndez-Cabañas ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Type Iv Pili ◽  
Acidithiobacillus Thiooxidans ◽  
Type Iv ◽  
Associated Proteins

scholarly journals Distribution of Genes Encoding Nucleoid-Associated Protein Homologs in Plasmids

2011 ◽  
Vol 2011 ◽  
pp. 1-30 ◽  
Author(s):  
Toshiharu Takeda ◽  
Choong-Soo Yun ◽  
Masaki Shintani ◽  
Hisakazu Yamane ◽  
Hideaki Nojiri
Keyword(s):  
Transcriptional Regulation ◽  
Conjugative Transfer ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Ns Gene ◽  
Expression Of Genes ◽  
Bacterial Nucleoid ◽  
Genes Encoding ◽  
Associated Proteins ◽  
Nucleoprotein Complexes

Bacterial nucleoid-associated proteins (NAPs) form nucleoprotein complexes and influence the expression of genes. Recent studies have shown that some plasmids carry genes encoding NAP homologs, which play important roles in transcriptional regulation networks between plasmids and host chromosomes. In this study, we determined the distributions of the well-known NAPs Fis, H-NS, HU, IHF, and Lrp and the newly found NAPs MvaT and NdpA among the whole-sequenced 1382 plasmids found in Gram-negative bacteria. Comparisons between NAP distributions and plasmid features (size, G+C content, and putative transferability) were also performed. We found that larger plasmids frequently have NAP gene homologs. Plasmids with H-NS gene homologs had less G+C content. It should be noted that plasmids with the NAP gene homolog also carried the relaxase gene involved in the conjugative transfer of plasmids more frequently than did those without the NAP gene homolog, implying that plasmid-encoded NAP homologs positively contribute to transmissible plasmids.

scholarly journals Expression of Type IV Pili by Moraxella catarrhalis Is Essential for Natural Competence and Is Affected by Iron Limitation

2004 ◽  
Vol 72 (11) ◽  
pp. 6262-6270 ◽  
Author(s):  
Nicole R. Luke ◽  
Amy J. Howlett ◽  
Jianqiang Shao ◽  
Anthony A. Campagnari
Keyword(s):  
Moraxella Catarrhalis ◽  
Pathogenic Bacteria ◽  
Type Iv Pili ◽  
Protein Subunit ◽  
Electron Microscopic ◽  
Type Iv ◽  
Wide Range ◽  
Genes Encoding ◽  
Microscopic Studies

ABSTRACT Type IV pili, filamentous surface appendages primarily composed of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of pathogenic bacteria. Although previous electron microscopic studies suggested that pili might be present on the surface of Moraxella catarrhalis isolates, detailed molecular and phenotypic analyses of these structures have not been reported to date. We identified and cloned the M. catarrhalis genes encoding PilA, the major pilin subunit, PilQ, the outer membrane secretin through which the pilus filament is extruded, and PilT, the NTPase that mediates pilin disassembly and retraction. To initiate investigation of the role of this surface organelle in pathogenesis, isogenic pilA, pilT, and pilQ mutants were constructed in M. catarrhalis strain 7169. Comparative analyses of the wild-type 7169 strain and three isogenic pil mutants demonstrated that M. catarrhalis expresses type IV pili that are essential for natural genetic transformation. Our studies suggest type IV pilus production by M. catarrhalis is constitutive and ubiquitous, although pilin expression was demonstrated to be iron responsive and Fur regulated. These data indicate that additional studies aimed at elucidating the prevalence and role of type IV pili in the pathogenesis and host response to M. catarrhalis infections are warranted.

scholarly journals Cyclic Di-GMP Binding by an Assembly ATPase (PilB2) and Control of Type IV Pilin Polymerization in the Gram-Positive Pathogen Clostridium perfringens

2017 ◽  
Vol 199 (10) ◽  
Author(s):  
William A. Hendrick ◽  
Mona W. Orr ◽  
Samantha R. Murray ◽  
Vincent T. Lee ◽  
Stephen B. Melville
Keyword(s):  
Clostridium Perfringens ◽  
Biochemical Characterization ◽  
Core Protein ◽  
Type Iv Pili ◽  
Host Cells ◽  
Dependent Manner ◽  
Gram Positive ◽  
Content Type ◽  
Type Iv

ABSTRACT The Gram-positive pathogen Clostridium perfringens possesses type IV pili (TFP), which are extracellular fibers that are polymerized from a pool of pilin monomers in the cytoplasmic membrane. Two proteins that are essential for pilus functions are an assembly ATPase (PilB) and an inner membrane core protein (PilC). Two homologues each of PilB and PilC are present in C. perfringens, called PilB1/PilB2 and PilC1/PilC2, respectively, along with four pilin proteins, PilA1 to PilA4. The gene encoding PilA2, which is considered the major pilin based on previous studies, is immediately downstream of the pilB2 and pilC2 genes. Purified PilB2 had ATPase activity, bound zinc, formed hexamers even in the absence of ATP, and bound the second messenger molecule cyclic di-GMP (c-di-GMP). Circular dichroism spectroscopy of purified PilC2 indicated that it retained its predicted degree of alpha-helical secondary structure. Even though no direct interactions between PilB2 and PilC2 could be detected in vivo or in vitro even in the presence of c-di-GMP, high levels of expression of a diguanylate cyclase from C. perfringens (CPE1788) stimulated polymerization of PilA2 in a PilB2- and PilC2-dependent manner. These results suggest that PilB2 activity is controlled by c-di-GMP levels in vivo but that PilB2-PilC2 interactions are either transitory or of low affinity, in contrast to results reported previously from in vivo studies of the PilB1/PilC1 pair in which PilC1 was needed for polar localization of PilB1. This is the first biochemical characterization of a c-di-GMP-dependent assembly ATPase from a Gram-positive bacterium. IMPORTANCE Type IV pili (TFP) are protein fibers involved in important bacterial functions, including motility, adherence to surfaces and host cells, and natural transformation. All clostridia whose genomes have been sequenced show evidence of the presence of TFP. The genetically tractable species Clostridium perfringens was used to study proteins involved in polymerizing the pilin, PilA2, into a pilus. The assembly ATPase PilB2 and its cognate membrane protein partner, PilC2, were purified. PilB2 bound the intracellular signal molecule c-di-GMP. Increased levels of intracellular c-di-GMP led to increased polymerization of PilA2, indicating that Gram-positive bacteria use this molecule to regulate pilus synthesis. These findings provide valuable information for understanding how pathogenic clostridia regulate TFP to cause human diseases.

scholarly journals Flagellar Mutants Have Reduced Pilus Synthesis in Caulobacter crescentus

2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Courtney K. Ellison ◽  
Douglas B. Rusch ◽  
Yves V. Brun
Keyword(s):  
Cell Biology ◽  
Regulatory Networks ◽  
Caulobacter Crescentus ◽  
Single Cells ◽  
Bacterial Species ◽  
Type Iv Pili ◽  
Content Type ◽  
Transcription Profiles ◽  
Type Iv ◽  
Genes Encoding

ABSTRACT Surface appendages, such as flagella and type IV pili, mediate a broad range of bacterial behaviors, including motility, attachment, and surface sensing. While many species harbor both flagella and type IV pili, little is known about how or if their syntheses are coupled. Here, we show that deletions of genes encoding different flagellum machinery components result in a reduction of pilus synthesis in Caulobacter crescentus. First, we show that different flagellar mutants exhibit different levels of sensitivity to a pilus-dependent phage and that fewer cells within populations of flagellar mutants make pili. Furthermore, we find that single cells within flagellar mutant populations produce fewer pili per cell. We demonstrate that these gene deletions result in reduced transcription of pilus-associated genes and have a slight but significant effect on general transcription profiles. Finally, we show that the decrease in pilus production is due to a reduction in the pool of pilin subunits that are polymerized into pilus fibers. These data demonstrate that mutations in flagellar gene components not only affect motility but also can have considerable and unexpected consequences for other aspects of cell biology. IMPORTANCE Most bacterial species synthesize surface-exposed appendages that are important for environmental interactions and survival under diverse conditions. It is often assumed that these appendages act independently of each other and that mutations in either system can be used to assess functionality in specific processes. However, we show that mutations in flagellar genes can impact the production of type IV pili, as well as alter general RNA transcriptional profiles compared to a wild-type strain. These data demonstrate that seemingly simple mutations can broadly affect cell-regulatory networks.

scholarly journals Pilin-Like Proteins in the Extremely Thermophilic Bacterium Thermus thermophilus HB27: Implication in Competence for Natural Transformation and Links to Type IV Pilus Biogenesis

2003 ◽  
Vol 69 (7) ◽  
pp. 3695-3700 ◽  
Author(s):  
Alexandra Friedrich ◽  
Judit Rumszauer ◽  
Anke Henne ◽  
Beate Averhoff
Keyword(s):  
Natural Transformation ◽  
Thermus Thermophilus ◽  
Thermophilic Bacterium ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Significant Similarity ◽  
High Frequencies ◽  
Type Iv ◽  
Genes Encoding ◽  
Pilus Biogenesis

ABSTRACT The extreme thermophile Thermus thermophilus HB27 exhibits high frequencies of natural transformation. Although we recently reported identification of the first competence genes in Thermus, the molecular basis of DNA uptake is unknown. A pilus-like structure is assumed to be involved. Twelve genes encoding prepilin-like proteins were identified in three loci in the genome of T. thermophilus. Mutational analyses, described in this paper, revealed that one locus, which contains four genes that encode prepilin-like proteins (pilA1 to pilA4), is essential for natural transformation. Additionally, comZ, a new competence gene with no similarity to known genes, was identified. Analysis of the piliation phenotype revealed wild-type piliation of a pilA1-pilA3Δkat mutant and a comZ mutant, whereas a pilA4 mutant was found to be completely devoid of pilus structures. These findings, together with the significant similarity of PilA4 to prepilins, led to the conclusion that the T. thermophilus pilus structures are type IV pili. Furthermore, the loss of the transformation and piliation phenotype in the pilA4 mutant suggests that type IV pili are implicated in natural transformation of T. thermophilus HB27.

scholarly journals Identification of an Operon, Pil-Chp, That Controls Twitching Motility and Virulence in Xylella fastidiosa

2011 ◽  
Vol 24 (10) ◽  
pp. 1198-1206 ◽  
Author(s):  
Luciana Cursino ◽  
Cheryl D. Galvani ◽  
Dusit Athinuwat ◽  
Paulo A. Zaini ◽  
Yaxin Li ◽  
...  
Keyword(s):  
Xylella Fastidiosa ◽  
Severe Disease ◽  
Type Iv Pili ◽  
Plant Diseases ◽  
Twitching Motility ◽  
In Planta ◽  
Disease Manifestation ◽  
Phytopathogenic Bacterium ◽  
Type Iv ◽  
Genes Encoding

Xylella fastidiosa is an important phytopathogenic bacterium that causes many serious plant diseases, including Pierce's disease of grapevines. Disease manifestation by X. fastidiosa is associated with the expression of several factors, including the type IV pili that are required for twitching motility. We provide evidence that an operon, named Pil-Chp, with genes homologous to those found in chemotaxis systems, regulates twitching motility. Transposon insertion into the pilL gene of the operon resulted in loss of twitching motility (pilL is homologous to cheA genes encoding kinases). The X. fastidiosa mutant maintained the type IV pili, indicating that the disrupted pilL or downstream operon genes are involved in pili function, and not biogenesis. The mutated X. fastidiosa produced less biofilm than wild-type cells, indicating that the operon contributes to biofilm formation. Finally, in planta the mutant produced delayed and less severe disease, indicating that the Pil-Chp operon contributes to the virulence of X. fastidiosa, presumably through its role in twitching motility.

scholarly journals Ancient ubiquitous protein-1 mediates sterol-induced ubiquitination of 3-hydroxy-3-methylglutaryl CoA reductase in lipid droplet–associated endoplasmic reticulum membranes

2013 ◽  
Vol 24 (3) ◽  
pp. 169-183 ◽  
Author(s):  
Youngah Jo ◽  
Isamu Z. Hartman ◽  
Russell A. DeBose-Boyd
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Droplet ◽  
Lipid Droplets ◽  
Regulatory Element ◽  
Cholesterol Homeostasis ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Element Binding Protein ◽  
Associated Proteins ◽  
Coa Reductase

Sterol-induced binding to Insigs in endoplasmic reticulum (ER) membranes triggers ubiquitination of the cholesterol biosynthetic enzyme 3-hydroxy-3-methylglutaryl CoA reductase. This ubiquitination, which is mediated by Insig-associated ubiquitin ligases gp78 and Trc8, is obligatory for extraction of reductase from lipid droplet–associated ER membranes into the cytosol for proteasome-mediated, ER-associated degradation (ERAD). In this study, we identify lipid droplet–associated, ancient, ubiquitous protein-1 (Aup1) as one of several proteins that copurify with gp78. RNA interference (RNAi) studies show that Aup1 recruits the ubiquitin-conjugating enzyme Ubc7 to lipid droplets and facilitates its binding to both gp78 and Trc8. The functional significance of these interactions is revealed by the observation that RNAi-mediated knockdown of Aup1 blunts sterol-accelerated ubiquitination of reductase, which appears to occur in lipid droplet–associated membranes and subsequent ERAD of the enzyme. In addition, Aup1 knockdown inhibits ERAD of Insig-1, another substrate for gp78, as well as that of membrane-bound precursor forms of sterol-regulatory, element-binding protein-1 and -2, transcription factors that modulate expression of genes encoding enzymes required for cholesterol synthesis. Considered together, these findings not only implicate a role for Aup1 in maintenance of intracellular cholesterol homeostasis, but they also highlight the close connections among ERAD, lipid droplets, and lipid droplet–associated proteins.

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