scholarly journals Localization and characterization of Xylella fastidiosa haemagglutinin adhesins

Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2172-2179 ◽  
Author(s):  
Tanja M. Voegel ◽  
Jeremy G. Warren ◽  
Ayumi Matsumoto ◽  
Michele M. Igo ◽  
Bruce C. Kirkpatrick
Keyword(s):  
Molecular Mass ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Xylella Fastidiosa ◽  
Membrane Vesicles ◽  
Cell Aggregation ◽  
Pathogenic Bacterium ◽  
Plant Pathogenic Bacterium ◽  
Gram Negative

Xylella fastidiosa is a Gram-negative, xylem-inhabiting, plant-pathogenic bacterium responsible for several important diseases including Pierce's disease (PD) of grapevines. The bacteria form biofilms in grapevine xylem that contribute to the occlusion of the xylem vessels. X. fastidiosa haemagglutinin (HA) proteins are large afimbrial adhesins that have been shown to be crucial for biofilm formation. Little is known about the mechanism of X. fastidiosa HA-mediated cell–cell aggregation or the localization of the adhesins on the cell. We generated anti-HA antibodies and show that X. fastidiosa HAs are present in the outer membrane and secreted both as soluble proteins and in membrane vesicles. Furthermore, the HA pre-proteins are processed from the predicted molecular mass of 360 kDa to a mature 220 kDa protein. Based on this information, we are evaluating a novel form of potential resistance against PD by generating HA-expressing transgenic grapevines.

Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter
Keyword(s):  
Outer Membrane ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Membrane Channels ◽  
Gram Negative ◽  
Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

scholarly journals Characterization of Regulatory Pathways in Xylella fastidiosa: Genes and Phenotypes Controlled by gacA

2009 ◽  
Vol 75 (8) ◽  
pp. 2275-2283 ◽  
Author(s):  
Xiang Yang Shi ◽  
C. Korsi Dumenyo ◽  
Rufina Hernandez-Martinez ◽  
Hamid Azad ◽  
Donald A. Cooksey
Keyword(s):  
Pseudomonas Syringae ◽  
Biofilm Formation ◽  
Xylella Fastidiosa ◽  
Cell Aggregation ◽  
Toxin Gene ◽  
Tomato Dc3000 ◽  
Disease Symptoms ◽  
Regulatory Pathways ◽  
Physiological Processes

ABSTRACT The xylem-limited, insect-transmitted bacterium Xylella fastidiosa causes Pierce's disease in grapes through cell aggregation and vascular clogging. GacA controls various physiological processes and pathogenicity factors in many gram-negative bacteria, including biofilm formation in Pseudomonas syringae pv. tomato DC3000. Cloned gacA of X. fastidiosa was found to restore the hypersensitive response and pathogenicity in gacA mutants of P. syringae pv. tomato DC3000 and Erwinia amylovora. A gacA mutant of X. fastidiosa (DAC1984) had significantly reduced abilities to adhere to a glass surface, form biofilm, and incite disease symptoms on grapevines, compared with the parent (A05). cDNA microarray analysis identified 7 genes that were positively regulated by GacA, including xadA and hsf, predicted to encode outer membrane adhesion proteins, and 20 negatively regulated genes, including gumC and an antibacterial polypeptide toxin gene, cvaC. These results suggest that GacA of X. fastidiosa regulates many factors, which contribute to attachment and biofilm formation, as well as some physiological processes that may enhance the adaptation and tolerance of X. fastidiosa to environmental stresses and the competition within the host xylem.

scholarly journals Complete genome resources for Xylella fastidiosa strains AlmaEM3 and BB08-1 reveal prophage-associated structural variation among blueberry-infecting strains.

2021 ◽  
Author(s):  
Michael O'Leary ◽  
Luis F. F. Arias-Giraldo ◽  
Lindsey Burbank ◽  
Leonardo De La Fuente ◽  
Blanca B. Landa
Keyword(s):  
Structural Variation ◽  
Reference Strain ◽  
Genetic Characterization ◽  
Xylella Fastidiosa ◽  
Plant Pathogenic Bacterium ◽  
Hybrid Assembly ◽  
Gram Negative ◽  
Wide Geographical Distribution ◽  
Sequence Types

Xylella fastidiosa is a gram-negative plant pathogenic bacterium with wide geographical distribution and host range. X. fastidiosa strains are separated into genetically distinct subspecies, and further categorized into sequence types (ST). Genetic characterization of X. fastidiosa strains infecting blueberry has revealed that strains of subspecies multiplex and fastidiosa are capable of causing bacterial leaf scorch disease of blueberry under field conditions. To better elucidate the relationships among blueberry-infecting X. fastidiosa subsp. multiplex strains, we completed the genomes of an ST 42 strain, AlmaEM3, and a ST 43 strain, BB08-1, using a hybrid assembly approach. Comparison of these assemblies reveals a large (0.95 Mb) chromosomal inversion in BB08-1 relative to AlmaEM3 and the reference strain M12, likely resulting from recombination between prophage regions.

scholarly journals Whole Genome Sequences of Two Xylella fastidiosa Strains (M12 and M23) Causing Almond Leaf Scorch Disease in California

2010 ◽  
Vol 192 (17) ◽  
pp. 4534-4534 ◽  
Author(s):  
J. Chen ◽  
G. Xie ◽  
S. Han ◽  
O. Chertkov ◽  
D. Sims ◽  
...  
Keyword(s):  
Complete Genome ◽  
Xylella Fastidiosa ◽  
Pathogenic Bacterium ◽  
Whole Genome ◽  
Plant Pathogenic Bacterium ◽  
Genome Sequences ◽  
Gram Negative ◽  
Leaf Scorch ◽  
Genome Information ◽  
Almond Leaf Scorch

ABSTRACT Xylella fastidiosa is a Gram-negative plant-pathogenic bacterium causing many economically important diseases, including almond leaf scorch disease (ALSD) in California. Genome information greatly facilitates research on this nutritionally fastidious organism. Here we report the complete genome sequences of two ALSD strains of this bacterium, M12 and M23.

scholarly journals Outer Membrane Vesicles Released From Aeromonas Strains Are Involved in the Biofilm Formation

2021 ◽  
Vol 11 ◽  
Author(s):  
Soshi Seike ◽  
Hidetomo Kobayashi ◽  
Mitsunobu Ueda ◽  
Eizo Takahashi ◽  
Keinosuke Okamoto ◽  
...  
Keyword(s):  
Amino Acid ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Amino Acid Sequences ◽  
Bacterial Biofilm ◽  
Gram Negative Bacteria ◽  
Gram Negative

Aeromonas spp. are Gram-negative rod-shaped bacteria ubiquitously distributed in diverse water sources. Several Aeromonas spp. are known as human and fish pathogens. Recently, attention has been focused on the relationship between bacterial biofilm formation and pathogenicity or drug resistance. However, there have been few reports on biofilm formation by Aeromonas. This study is the first to examine the in vitro formation and components of the biofilm of several Aeromonas clinical and environmental strains. A biofilm formation assay using 1% crystal violet on a polystyrene plate revealed that most Aeromonas strains used in this study formed biofilms but one strain did not. Analysis of the basic components contained in the biofilms formed by Aeromonas strains confirmed that they contained polysaccharides containing GlcNAc, extracellular nucleic acids, and proteins, as previously reported for the biofilms of other bacterial species. Among these components, we focused on several proteins fractionated by SDS-PAGE and determined their amino acid sequences. The results showed that some proteins existing in the Aeromonas biofilms have amino acid sequences homologous to functional proteins present in the outer membrane of Gram-negative bacteria. This result suggests that outer membrane components may affect the biofilm formation of Aeromonas strains. It is known that Gram-negative bacteria often release extracellular membrane vesicles from the outer membrane, so we think that the outer membrane-derived proteins found in the Aeromonas biofilms may be derived from such membrane vesicles. To examine this idea, we next investigated the ability of Aeromonas strains to form outer membrane vesicles (OMVs). Electron microscopic analysis revealed that most Aeromonas strains released OMVs outside the cells. Finally, we purified OMVs from several Aeromonas strains and examined their effect on the biofilm formation. We found that the addition of OMVs dose-dependently promoted biofilm formation, except for one strain that did not form biofilms. These results suggest that the OMVs released from the bacterial cells are closely related to the biofilm formation of Aeromonas strains.

scholarly journals Relationship Between Membrane Vesicles, Extracellular ATP and Biofilm Formation in Antarctic Gram-Negative Bacteria

2020 ◽  
Author(s):  
Nicolas Baeza ◽  
Elena Mercade
Keyword(s):  
Biofilm Formation ◽  
Membrane Vesicles ◽  
Metabolic Cost ◽  
Extracellular Atp ◽  
Gram Negative Bacteria ◽  
Bacterial Survival ◽  
Gram Negative ◽  
Two Factors ◽  
And Control

Abstract Biofilms offer a safe environment that favors bacterial survival; for this reason, most pathogenic and environmental bacteria live integrated in biofilm communities. The development of biofilms is complex and involves many factors, which need to be studied in order to understand bacterial behavior and control biofilm formation when necessary. We used a collection of cold-adapted Antarctic Gram-negative bacteria to study whether their ability to form biofilms is associated with a capacity to produce membrane vesicles and secrete extracellular ATP. In most of the studied strains, no correlation was found between biofilm formation and these two factors. Only Shewanella vesiculosa M7T secreted high levels of extracellular ATP, and its membrane vesicles caused a significant increase in the speed and amount of biofilm formation. In this strain, an important portion of the exogenous ATP was contained in membrane vesicles, where it was protected from apyrase treatment. These results confirm that ATP influences biofilm formation. Although the role of extracellular ATP in prokaryotes is still not well understood, the metabolic cost of its production suggests it has an important function, such as a role in biofilm formation. Thus, the liberation of extracellular ATP through membrane vesicles and its function deserve further study.

Molecular Characterization of Biofilm Formation and Attachment of Salmonella enterica Serovar Typhimurium DT104 on Food Contact Surfaces

2009 ◽  
Vol 72 (9) ◽  
pp. 1841-1847 ◽  
Author(s):  
SHIN-HEE KIM ◽  
CHENG-I WEI
Keyword(s):  
Outer Membrane ◽  
Biofilm Formation ◽  
Rna Binding ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Membrane Expression ◽  
Exopolymeric Substances ◽  
Food Contact Surfaces ◽  
Serovar Typhimurium ◽  
Contact Surfaces

The molecular mechanism of biofilm formation by Salmonella Typhimuriun DT104 was characterized for a better understanding of its attachment and colonization in food processing environments. A library of random mutagenized clones was screened for phenotypic analyses of their ability to form biofilm, pellicle, curli, and cellulose. The genes identified were involved in lipopolysaccharide synthesis, assembly of flagella, regulation of rRNA biosynthesis, and outer membrane transportation and signaling. The insertion of transposon in flgK, rfbA, nusB, and pnp genes resulted in decreased biofilm formation. Alterations of flagellar and lipopolysaccharide production were confirmed in the flgK mutant and rfbA mutant, respectively. Biofilm formation by these four mutants in meat and poultry broths and their attachment on surfaces of stainless steel and glass were significantly reduced compared with those of the wild-type strain (P &lt; 0.05). On the contrary, the mutation of STM4263 and yjcC genes in Salmonella Typhimuriun DT104 resulted in increased biofilm formation and attachment of the species in tested broths and on contact surfaces. Our findings suggest that many factors, such as production of exopolymeric substances and their efficient transportation through outer membrane, expression of flagella, and regulation of exoribonucleases and RNA-binding protein, could be involved in biofilm formation and attachment of Salmonella Typhimurium DT104 on contact surfaces.

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