scholarly journals Exchange of Xcp (Gsp) Secretion Machineries betweenPseudomonas aeruginosa and Pseudomonas alcaligenes: Species Specificity Unrelated to Substrate Recognition

2001 ◽  
Vol 183 (3) ◽  
pp. 959-967 ◽  
Author(s):  
Arjan de Groot ◽  
Margot Koster ◽  
Manon Gérard-Vincent ◽  
Gijs Gerritse ◽  
Andrée Lazdunski ◽  
...  
Keyword(s):  
Secretory Pathway ◽  
Gram Negative Bacteria ◽  
Gene Products ◽  
Type Ii ◽  
Gram Negative ◽  
Secretion Pathway ◽  
Heat Stable ◽  
Pseudomonas Alcaligenes ◽  
Mutant Complementation ◽  
Species Specific

ABSTRACT Pseudomonas aeruginosa and Pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type II or general secretory pathway, which requires at least 12 xcp gene products (XcpA and XcpP to -Z). Despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. Based on results obtained with Erwinia, it has been proposed that the XcpP and/or XcpQ homologs determine this secretion specificity (M. Linderberg, G. P. Salmond, and A. Collmer, Mol. Microbiol. 20:175–190, 1996). In the present study, we report that XcpP and XcpQ of P. alcaligenes could not substitute for their respectiveP. aeruginosa counterparts. However, these complementation failures could not be correlated to species-specific recognition of exoproteins, since these bacteria could secrete exoproteins of each other. Moreover, when P. alcaligenes xcpP andxcpQ were expressed simultaneously in a P. aeruginosa xcpPQ deletion mutant, complementation was observed, albeit only on agar plates and not in liquid cultures. After growth in liquid culture the heat-stable P. alcaligenes XcpQ multimers were not detected, whereas monomers were clearly visible. Together, our results indicate that the assembly of a functional Xcp machinery requires species-specific interactions between XcpP and XcpQ and between XcpP or XcpQ and another, as yet uncharacterized component(s).

scholarly journals Legionella pneumophila Contains a Type II General Secretion Pathway Required for Growth in Amoebae as Well as for Secretion of the Msp Protease

1999 ◽  
Vol 67 (7) ◽  
pp. 3662-3666 ◽  
Author(s):  
Laura M. Hales ◽  
Howard A. Shuman
Keyword(s):  
Legionella Pneumophila ◽  
Acanthamoeba Castellanii ◽  
Gram Negative Bacteria ◽  
Type Ii ◽  
Free Living ◽  
Gram Negative ◽  
Secretion Pathway ◽  
Free Living Amoeba ◽  
Substitution Mutation

ABSTRACT We report the identification of a set of Legionella pneumophila genes that encode products with homology to proteins of the type II general secretion pathway of gram-negative bacteria. A strain containing a deletion-substitution mutation of two of these genes was unable to secrete the Msp protease. This strain was unable to multiply within the free-living amoeba Acanthamoeba castellanii yet was able to kill HL-60-derived macrophages. Because Msp is not required for growth in amoebae, other proteins which are important for growth in amoebae are likely secreted by this pathway.

scholarly journals Lysis Genes of the Bacillus subtilisDefective Prophage PBSX

1998 ◽  
Vol 180 (8) ◽  
pp. 2110-2117 ◽  
Author(s):  
Susanne Krogh ◽  
Steen T. Jørgensen ◽  
Kevin M. Devine
Keyword(s):  
Functional Analysis ◽  
Host Cell ◽  
Expression System ◽  
Cell Lysis ◽  
Lethal Gene ◽  
Gram Negative Bacteria ◽  
Gene Products ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Exported Protein

ABSTRACT Four genes identified within the late operon of PBSX show characteristics expected of a host cell lysis system; they arexepA, encoding an exported protein; xhlA, encoding a putative membrane-associated protein; xhlB, encoding a putative holin; and xlyA, encoding a putative endolysin. In this work, we have assessed the contribution of each gene to host cell lysis by expressing the four genes in different combinations under the control of their natural promoter located on the chromosome of Bacillus subtilis 168. The results show thatxepA is unlikely to be involved in host cell lysis. Expression of both xhlA and xhlB is necessary to effect host cell lysis of B. subtilis. Expression ofxhlB (encoding the putative holin) together withxlyA (encoding the endolysin) cannot effect cell lysis, indicating that the PBSX lysis system differs from those identified in the phages of gram-negative bacteria. Since host cell lysis can be achieved when xlyA is inactivated, it is probable that PBSX encodes a second endolysin activity which also uses XhlA and XhlB for export from the cell. The chromosome-based expression system developed in this study to investigate the functions of the PBSX lysis genes should be a valuable tool for the analysis of other host cell lysis systems and for expression and functional analysis of other lethal gene products in gram-positive bacteria.

scholarly journals STUDIES ON NATURAL ANTIBODIES TO GRAM-NEGATIVE BACTERIA

1962 ◽  
Vol 115 (1) ◽  
pp. 131-146 ◽  
Author(s):  
J. Gabriel Michael ◽  
James L. Whitby ◽  
Maurice Landy
Keyword(s):  
Normal Serum ◽  
Natural Antibodies ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Germ Free ◽  
Heat Stable ◽  
Normal Human ◽  
Quantitative Absorption ◽  
Parallel Tests ◽  
Immune Antibody

A study was made of the origin, occurrence, and properties of natural antibodies to Gram-negative bacteria in the normal serum of several species. Antibody was measured by a procedure based on the bactericidal reaction carried out under conditions in which activity was a function of the amount of antibody contributed by the test serum. Antibody to seven genera of the family Enterobacteriaceae were demonstrated in normal human serum. The specificity of these antibodies was affirmed by absorption with homologous bacteria and by inhibition of bactericidal activity with purified homologous somatic antigen. Absorption with graded amounts of bacterial suspensions showed that a large excess of bacteria led to non-specific removal of antibodies. Analogous findings were also made with immune antibody. As determined by quantitative absorption tests no difference could be found in the avidity of natural and immune antibody. Natural antibody in the serum of various species differed considerably as regards their lability to heat, but in parallel tests immune antibody of each species was significantly more heat-stable. The time and appearance of the antibodies varied in young animals, of different species. Mice developed these antibodies at the earliest age, with guinea pigs, rats, and rabbits following in that order. Serum from germ-free rats and chickens had no demonstrable antibodies to E. coli or S. typhosa whereas these antibodies were present in the serum of litter mates reared under conventional conditions. On the other hand germ-free and conventional mice did not differ appreciably as regards the levels of these same antibodies.

scholarly journals NBTI 5463 Is a Novel Bacterial Type II Topoisomerase Inhibitor with Activity against Gram-Negative Bacteria andIn VivoEfficacy

2014 ◽  
Vol 58 (7) ◽  
pp. 4250-4250
Author(s):  
Thomas J. Dougherty ◽  
Asha Nayar ◽  
Joseph V. Newman ◽  
Sussie Hopkins ◽  
Gregory G. Stone ◽  
...  
Keyword(s):  
Gram Negative Bacteria ◽  
Type Ii ◽  
Gram Negative ◽  
Topoisomerase Inhibitor ◽  
Bacterial Type

Characterization of eight beta-lactamases of Gram-negative bacteria

1982 ◽  
Vol 152 (2) ◽  
pp. 567-571
Author(s):  
T Sawai ◽  
M Kanno ◽  
K Tsukamoto
Keyword(s):  
Assay Method ◽  
Gram Negative Bacteria ◽  
Beta Lactam ◽  
Ph Optimum ◽  
Gram Negative ◽  
Beta Lactamases ◽  
Beta Lactam Antibiotics ◽  
R Plasmids ◽  
Ph Stat ◽  
Species Specific

Eight kinds of beta-lactamases produced by gram-negative bacteria were characterized by the following properties: molecular weight, isoelectric point, pH optimum, molecular activity, immunochemical reactivity, and kinetic parameters with respect to twelve kinds of common beta-lactam antibiotics. These beta-lactamases included two types of penicillinases mediated by R plasmids and six kinds of species-specific cephalosporinases. To determine a reliable value of the kinetic parameter, Km, we introduced a continuous and acidimetric assay method of beta-lactamase activity with a pH stat.

scholarly journals Type V Protein Secretion Pathway: the Autotransporter Story

2004 ◽  
Vol 68 (4) ◽  
pp. 692-744 ◽  
Author(s):  
Ian R. Henderson ◽  
Fernando Navarro-Garcia ◽  
Mickaël Desvaux ◽  
Rachel C. Fernandez ◽  
Dlawer Ala'Aldeen
Keyword(s):  
Protein Secretion ◽  
Bacterial Infections ◽  
Protein Translocation ◽  
Research Field ◽  
Secreted Proteins ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
V Protein ◽  
Secretion Pathway ◽  
Type V

SUMMARY Gram-negative bacteria possess an outer membrane layer which constrains uptake and secretion of solutes and polypeptides. To overcome this barrier, bacteria have developed several systems for protein secretion. The type V secretion pathway encompasses the autotransporter proteins, the two-partner secretion system, and the recently described type Vc or AT-2 family of proteins. Since its discovery in the late 1980s, this family of secreted proteins has expanded continuously, due largely to the advent of the genomic age, to become the largest group of secreted proteins in gram-negative bacteria. Several of these proteins play essential roles in the pathogenesis of bacterial infections and have been characterized in detail, demonstrating a diverse array of function including the ability to condense host cell actin and to modulate apoptosis. However, most of the autotransporter proteins remain to be characterized. In light of new discoveries and controversies in this research field, this review considers the autotransporter secretion process in the context of the more general field of bacterial protein translocation and exoprotein function.

A thiol-activated hemolysin in Gram-negative bacteria

1985 ◽  
Vol 31 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Inés Albesa ◽  
Lucila Isabel Barberis ◽  
María Cristina Pajaro ◽  
María Cecilia Farnochi ◽  
Alberto Jorge Eraso
Keyword(s):  
Klebsiella Pneumoniae ◽  
Blood Cell ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Gram Negative Bacteria ◽  
Bacterial Lysate ◽  
Gram Negative ◽  
Heat Stable ◽  
Initial Description ◽  
Chicken Erythrocytes

An investigation of Klebsiella pneumoniae hemolytic activity was carried out. Strains isolated from different infected specimens were hemolytic in tryptic soy agar with rabbit blood; incubation at 4 °C enhanced the hemolysis. There was no evident red blood cell lysis in plates with human, sheep, mouse, and chicken erythrocytes. The culture in tryptic soy broth, its supernatant and bacterial lysate did produce evident hemolysis of rabbit red blood cells when they were preincubated with 2-mercaptoethanol. Klebsiella pneumoniae hemolysin showed the Arrhenius effect, while temperatures over 60 °C for 10 min reduced the activity of crude hemolysin to zero; purified hemolysin, however, was heat stable. Two hemolysins active on rabbit red blood cells were purified and both shared several properties. This work represents the initial description of a thiol-activated hemolysin in Gram-negative bacteria.

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