scholarly journals Cloning, Sequencing, and Role in Serum Susceptibility of Porin II from Mesophilic Aeromonas hydrophila

2000 ◽  
Vol 68 (4) ◽  
pp. 1849-1854 ◽  
Author(s):  
Maria Mercé Nogueras ◽  
Susana Merino ◽  
Alicia Aguilar ◽  
Vicente Javier Benedi ◽  
Juan M. Tomás
Keyword(s):  
Escherichia Coli ◽  
Structural Gene ◽  
Aeromonas Hydrophila ◽  
Surface Molecule ◽  
E Coli ◽  
Genetic Position ◽  
O 11 ◽  
Insertion Mutants

ABSTRACT We cloned and sequenced the structural gene for Aeromonas hydrophila porin II from strain AH-3 (serogroup O:34). The genetic position of this gene, like that of ompF inEscherichia coli, is adjacent to aspC and transcribed in the same direction. However, upstream of the porin II gene no similarities with E. coli were found. We obtained defined insertion mutants in porin II gene either in A. hydrophila (O:34) or A. veronii sobria (serogroup O:11) serum-resistant or -sensitive strains. Furthermore, we complemented these mutants with a plasmid harboring only the porin II gene, which allowed us to define the role of porin II as an important surface molecule involved in serum susceptibility and C1q binding in these strains.

scholarly journals Pilus-Mediated Adherence of Haemophilus influenzae to Human Respiratory Mucins

2000 ◽  
Vol 68 (6) ◽  
pp. 3362-3367 ◽  
Author(s):  
Martin Kubiet ◽  
Reuben Ramphal ◽  
Allan Weber ◽  
Arnold Smith
Keyword(s):  
Escherichia Coli ◽  
Haemophilus Influenzae ◽  
Lung Disease ◽  
Gene Cluster ◽  
Otitis Media ◽  
Structural Gene ◽  
Chronic Lung Disease ◽  
Type B ◽  
E Coli

ABSTRACT Haemophilus influenzae, especially the nontypeable strains, are among the most common pathogens encountered in patients with chronic lung disease and otitis media. We and others have demonstrated that respiratory isolates of nontypeable H. influenzae bind to human mucins, but the mechanism of binding is not entirely clear. We have therefore examined the role of pili in the adherence of both type b and nontypeable H. influenzae to human respiratory mucins. We used isogenic H. influenzaestrains with a mutation in the structural gene for pilin (hifA), a laboratory H. influenzae strain transformed with a type b pilus gene cluster (from strain C54), antibodies raised against H. influenzae HifA, andEscherichia coli strains carrying a cloned type b pilus gene cluster (from strain AM30) in these studies. All bacteria lacking HifA or the pilus gene cluster had decreased adherence of piliatedH. influenzae to mucins, and Fab fragments of anti-HifA antibodies inhibited the adherence. E. coli strains carrying the cloned type b pilus gene cluster were six to seven times more adhesive than strains carrying the vector. The role of other putative adhesins was not examined and thus cannot be excluded, but these studies support a role for pili in the binding of H. influenzae to human respiratory mucins.

scholarly journals Efa1 Influences Colonization of the Bovine Intestine by Shiga Toxin-Producing Escherichia coli Serotypes O5 and O111

2002 ◽  
Vol 70 (9) ◽  
pp. 5158-5166 ◽  
Author(s):  
Mark P. Stevens ◽  
Pauline M. van Diemen ◽  
Gad Frankel ◽  
Alan D. Phillips ◽  
Timothy S. Wallis
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Bacterial Attachment ◽  
Filamentous Actin ◽  
E Coli ◽  
Enterocyte Effacement ◽  
Number Of Bacteria ◽  
Insertion Mutants ◽  
Identical Gene

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) comprises a broad group of bacteria, some of which cause attaching and effacing (AE) lesions and enteritis in animals and humans. Non-O157 STEC serotypes contain a gene (efa1) that mediates attachment to cultured epithelial cells. An almost-identical gene in enteropathogenic E. coli (lifA) encodes lymphostatin, which inhibits the proliferation of mitogen-activated lymphocytes and the synthesis of proinflammatory cytokines. We have investigated the role of the efa1 gene in colonization of 4- and 11-day-old conventional calves by STEC serotypes O5 and O111. Our findings show that Efa1 is required for efficient colonization of the bovine intestinal tract by STEC, since efa1 deletion and insertion mutants were shed in the feces in significantly lower numbers. In addition, efa1 mutations dramatically reduced the number of bacteria associated with the intestinal epithelium. Expression and secretion of locus for enterocyte effacement-encoded type III secreted proteins that are required for adhesion and AE-lesion formation were impaired by mutation of efa1 in STEC but not by mutation of lifA in enteropathogenic E. coli. However, STEC efa1 mutants retain the ability to nucleate filamentous actin under sites of bacterial attachment to cultured eukaryotic cells. Efa1 is only the second STEC factor shown to influence carriage of the bacteria in the bovine intestine. Our data may have implications for strategies to reduce the prevalence of STEC in cattle.

scholarly journals A NEW MAP LOCATION FOR THE ilvB LOCUS OF ESCHERICHIA COLI

Genetics ◽  
1980 ◽  
Vol 96 (1) ◽  
pp. 59-77
Author(s):  
Thomas C Newman ◽  
Mark Levinthal
Keyword(s):  
Escherichia Coli ◽  
Structural Gene ◽  
Acetolactate Synthase ◽  
Deletion Mapping ◽  
Donor Strain ◽  
E Coli ◽  
Linkage Of Genes ◽  
Map Location ◽  
New Alleles

ABSTRACT We isolated, in E. coli K12, new alleles of the ilvB locus, the structural gene for acetolactate synthase isoenzyme I, and showed them to map at or near the ilvB619 site. The map position of the ilvB locus was redetermined because plasmids containing the ilvC-cya portion of the chromosome did not complement mutations at the ilvB locus. Furthermore, diploids for the ilvEDAC genes formed with these plasmids in an ilvHI background facilitated the isolation of the new ilvB alleles. The ilvB locus was remapped and found to be located at 81.5 minutes, between the uhp and dnaA loci. This location was determined by two- and three-point transductional crosses, deletion mapping and complementation with newly isolated plasmids. One of the new alleles of the ilvB gene is a mu-1 insertion. When present in the donor strain, this allele interferes with the linkage of genes flanking the mu-1 insertion, as well as the linkage of genes to either side of the mu-1 insertion.

scholarly journals Roles of the C-Terminal Amino Acids of Non-Hexameric Helicases: Insights from Escherichia coli UvrD

2021 ◽  
Vol 22 (3) ◽  
pp. 1018
Author(s):  
Hiroaki Yokota
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
Single Molecule ◽  
Underlying Mechanism ◽  
Amino Acid Sequences ◽  
E Coli ◽  
X Ray Crystallography ◽  
Terminal Amino

Helicases are nucleic acid-unwinding enzymes that are involved in the maintenance of genome integrity. Several parts of the amino acid sequences of helicases are very similar, and these quite well-conserved amino acid sequences are termed “helicase motifs”. Previous studies by X-ray crystallography and single-molecule measurements have suggested a common underlying mechanism for their function. These studies indicate the role of the helicase motifs in unwinding nucleic acids. In contrast, the sequence and length of the C-terminal amino acids of helicases are highly variable. In this paper, I review past and recent studies that proposed helicase mechanisms and studies that investigated the roles of the C-terminal amino acids on helicase and dimerization activities, primarily on the non-hexermeric Escherichia coli (E. coli) UvrD helicase. Then, I center on my recent study of single-molecule direct visualization of a UvrD mutant lacking the C-terminal 40 amino acids (UvrDΔ40C) used in studies proposing the monomer helicase model. The study demonstrated that multiple UvrDΔ40C molecules jointly participated in DNA unwinding, presumably by forming an oligomer. Thus, the single-molecule observation addressed how the C-terminal amino acids affect the number of helicases bound to DNA, oligomerization, and unwinding activity, which can be applied to other helicases.

scholarly journals Distribution of Lactoferrin Is Related with Dynamics of Neutrophils in Bacterial Infected Mice Intestine

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1496 ◽  
Author(s):  
Li Liang ◽  
Zhen-Jie Wang ◽  
Guang Ye ◽  
Xue-You Tang ◽  
Yuan-Yuan Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Mucosal Immunity ◽  
Mrna Levels ◽  
Iron Binding ◽  
E Coli ◽  
New Knowledge ◽  
Activated Neutrophils ◽  
Binding Glycoprotein

Lactoferrin (Lf) is a conserved iron-binding glycoprotein with antimicrobial activity, which is present in secretions that recover mucosal sites regarded as portals of invaded pathogens. Although numerous studies have focused on exogenous Lf, little is known about its expression of endogenous Lf upon bacterial infection. In this study, we investigated the distribution of Lf in mice intestine during Escherichia coli (E. coli) K88 infection. PCR and immunohistology staining showed that mRNA levels of Lf significantly increased in duodenum, ileum and colon, but extremely decreased in jejunum at 8 h and 24 h after infection. Meanwhile, endogenous Lf was mostly located in the lamina propria of intestine villi, while Lf receptor (LfR) was in the crypts. It suggested that endogenous Lf-LfR interaction might not be implicated in the antibacterial process. In addition, it was interesting to find that the infiltration of neutrophils into intestine tissues was changed similarly to Lf expression. It indicated that the variations of Lf expression were rather due to an equilibrium between the recruitment of neutrophils and degranulation of activated neutrophils. Thus, this new knowledge will pave the way to a more effective understanding of the role of Lf in intestinal mucosal immunity.

SATP (YaaH), a succinate–acetate transporter protein in Escherichia coli

2013 ◽  
Vol 454 (3) ◽  
pp. 585-595 ◽  
Author(s):  
Joana Sá-Pessoa ◽  
Sandra Paiva ◽  
David Ribas ◽  
Inês Jesus Silva ◽  
Sandra Cristina Viegas ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Succinic Acid ◽  
Critical Role ◽  
Amino Acid Residues ◽  
E Coli ◽  
Transporter Protein ◽  
Affinity Constants ◽  
In Trans

In the present paper we describe a new carboxylic acid transporter in Escherichia coli encoded by the gene yaaH. In contrast to what had been described for other YaaH family members, the E. coli transporter is highly specific for acetic acid (a monocarboxylate) and for succinic acid (a dicarboxylate), with affinity constants at pH 6.0 of 1.24±0.13 mM for acetic acid and 1.18±0.10 mM for succinic acid. In glucose-grown cells the ΔyaaH mutant is compromised for the uptake of both labelled acetic and succinic acids. YaaH, together with ActP, described previously as an acetate transporter, affect the use of acetic acid as sole carbon and energy source. Both genes have to be deleted simultaneously to abolish acetate transport. The uptake of acetate and succinate was restored when yaaH was expressed in trans in ΔyaaH ΔactP cells. We also demonstrate the critical role of YaaH amino acid residues Leu131 and Ala164 on the enhanced ability to transport lactate. Owing to its functional role in acetate and succinate uptake we propose its assignment as SatP: the Succinate–Acetate Transporter Protein.

scholarly journals Molecular survey of mcr1 and mcr2 plasmid mediated colistin resistance genes in Escherichia coli isolates of animal origin in Iran

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kayhan Ilbeigi ◽  
Mahdi Askari Badouei ◽  
Hossein Vaezi ◽  
Hassan Zaheri ◽  
Sina Aghasharif ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Companion Animals ◽  
Multidrug Resistant ◽  
Animal Origin ◽  
Colistin Resistance ◽  
E Coli ◽  
High Level ◽  
Farming Industry

Abstract Objectives The emergence of colistin-resistant Enterobacteriaceae from human and animal sources is one of the major public health concerns as colistin is the last-resort antibiotic for treating infections caused by multidrug-resistant Gram-negative bacteria. We aimed to determine the prevalence of the prototype widespread colistin resistance genes (mcr-1 and mcr-2) among commensal and pathogenic Escherichia coli strains isolated from food-producing and companion animals in Iran. Results A total of 607 E. coli isolates which were previously collected from different animal sources between 2008 and 2016 used to uncover the possible presence of plasmid-mediated colistin resistance genes (mcr-1 and mcr-2) by PCR. Overall, our results could not confirm the presence of any mcr-1 or mcr-2 positive E. coli among the studied isolates. It is concluded that despite the important role of food-producing animals in transferring the antibiotic resistance, they were not the main source for carriage of mcr-1 and mcr-2 in Iran until 2016. This study suggests that the other mcr variants (mcr-3 to mcr-9) might be responsible for conferring colistin resistance in animal isolates in Iran. The possible linkage between pig farming industry and high level of mcr carriage in some countries needs to be clarified in future prospective studies.

scholarly journals Drinking water and diarrhoeal disease due to Escherichia coli

2003 ◽  
Vol 1 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Paul R. Hunter
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Clinical Presentation ◽  
Diarrhoeal Disease ◽  
Central Place ◽  
E Coli ◽  
Related Disease ◽  
Direct Damage ◽  
Water Microbiology

Escherichia coli has had a central place in water microbiology for decades as an indicator of faecal pollution. It is only relatively recently that the role of E. coli as pathogen, rather than indicator, in drinking water has begun to be stressed. Interest in the role of E. coli as a cause of diarrhoeal disease has increased because of the emergence of E. coli O157:H7 and other enterohaemorrhagic E. coli, due to the severity of the related disease. There are enterotoxigenic, enteropathogenic, enterohaemorrhagic, enteroinvasive, enteroaggregative and diffusely adherent strains of E. coli. Each type of E. coli causes diarrhoeal disease through different mechanisms and each causes a different clinical presentation. Several of the types cause diarrhoea by the elaboration of one or more toxins, others by some other form of direct damage to epithelial cells. This paper discusses each of these types in turn and also describes their epidemiology, with particular reference to whether they are waterborne or not.

Growth of Selected Cross-Contaminating Bacterial Pathogens on Beef and Fish at 15 and 35°C+

1994 ◽  
Vol 57 (4) ◽  
pp. 337-340 ◽  
Author(s):  
AJIBOLA O. FAPOHUNDA ◽  
KENNETH W. MCMILLIN ◽  
DOUGLAS L. MARSHALL ◽  
W. M. WAITES
Keyword(s):  
Escherichia Coli ◽  
Clostridium Perfringens ◽  
Aeromonas Hydrophila ◽  
Growth Response ◽  
Cross Contamination ◽  
Limited Growth ◽  
E Coli ◽  
Fish Samples ◽  
Conditioning Temperature ◽  
The Tropics

Isolates of Escherichia coli and Clostridium perfringens from beef and Aeromonas hydrophila from fish were examined for their ability to survive and grow as cross-contaminates on nonnative tissues at simulated ambient (35°C) and aging/conditioning (15°C) temperatures of handling and retailing found in the tropics. Growth of all isolates over a 10-h period was greater (P < 0.05) on their native tissues at both temperatures. The aging/conditioning temperature effectively limited growth of E. coli and A. hydrophila to less than l-logl0 CFU/g and prevented growth of C. perfringens on beef and fish samples. All three isolates demonstrated characteristic mesophilic growth response on both tissues at 35°C during the 10-h retail period. The study suggests that two muscle food products could be jointly handled to efficiently use available storage/haulage capacity in tropical countries. Potential savings in space, labor and energy would be made if cross-contamination between the two products is minimized by available packaging and sanitizing technologies.

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