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J H Crosa

Publications and source records attributed to J H Crosa.

At least 91 records · Page 5Linked to original sources
PubMed1984

Phylogenetic relationships among Vibrio anguillarum plasmids.

Results of restriction endonuclease analysis and Southern blot hybridization suggest that the R-plasmids from Vibrio anguillarum strains isolated in Japan can be divided into at least four groups of homology depending on the time of their isolation and geographical source. Molecular cloning experiments allowed identification of specific restriction endonuclease fragments carrying the genes for either Cmr or Tcr as the common sequences between some of these groups of R-plasmids. The Cmr region from the V. anguillarum R-plasmids was homologous to the Cmr sequences of an R-plasmid isolated from another fish pathogen, Aeromonas salmonicida. The plasmid pJM1 from V. anguillarum strains isolated in the Pacific Northwest region of the United States, which encodes an iron transport system associated with the high-virulence phenotype of these strains, showed homology with two of the Japanese R-plasmids.

Aeromonas↗
PubMed1984

Lack of homology between the iron transport regions of two virulence-linked bacterial plasmids.

Two plasmids involved in bacterial virulence, the Escherichia coli plasmid pColV-K30 and the Vibrio anguillarum plasmid pJM1, have been studied with respect to the iron sequestering systems mediated by these two plasmids. Bioassay results show that the two systems are not related functionally because specific iron uptake-deficient mutants in each system cannot be cross-fed by the heterologous bacteria using culture supernatants from iron-proficient strains containing wild-type plasmids. DNA hybridization studies show an extensive lack of homology between regions involved in iron sequestration in both plasmids.

Biological Transport, Active↗
PubMed1984

Aerobactin iron transport genes commonly encoded by certain ColV plasmids occur in the chromosome of a human invasive strain of Escherichia coli K1.

The aerobactin-mediated iron uptake system encoded by pColV-K30 and other ColV plasmids has been associated with the ability of Escherichia coli strains to cause disease. We investigated whether the pColV-K30 aerobactin system is present in E. coli K1 VW187 isolated from a human neonate with meningitis. This strain exhibited a functional aerobactin-mediated iron uptake system, as assessed by a cross-feeding bioassay and by its sensitivity to cloacin, a bacteriocin that recognizes the outer membrane receptor for iron-aerobactin complexes. By using a variety of techniques, we could not find any plasmid harboring the aerobactin genes. Hybridization of restriction endonuclease-cleaved chromosomal DNA from strain VW187 with various clones containing subsets of the pColV-K30 aerobactin region showed that the aerobactin genes were located on a 10.5-kilobase-pair chromosomal HindIII restriction fragment which also contained IS1-like insertion sequences. The chromosomal aerobactin region showed a high degree of conservation when compared with the homologous region in plasmid pColV-K30, although it was located on a different restriction endonuclease site environment.

Bacterial Outer Membrane Proteins↗
PubMed1984

Aerobactin iron uptake sequences in plasmid ColV-K30 are flanked by inverted IS1-like elements and replication regions.

By using Southern blot hybridization procedures, we found that a specific sequence within a 16.3-kilobase HindIII restriction fragment of pColV-K30 was also present in at least three other pColV-K30 HindIII fragments. Restriction endonuclease mapping of these HindIII fragments indicated that two of these repeated sequences, identified as IS1-like, occur in reverse orientation adjacent to the ends of the aerobactin iron uptake region, also included in the 16.3-kilobase HindIII fragment. There are two distinct replication regions enclosing the IS1-flanked aerobactin genes. A pColV-K30 BamHI restriction endonuclease fragment, carrying one of these replication regions, showed homology with the F plasmid EcoRI fragment f5, which carries the F replication sequences.

Bacterial Outer Membrane Proteins↗
PubMed1984

Molecular cloning and expression of genetic determinants for the iron uptake system mediated by the Vibrio anguillarum plasmid pJM1.

Plasmid pJM1 from an invasive strain of Vibrio anguillarum encodes an iron uptake system which mediates the biosynthesis of a siderophore and a membrane receptor for the iron-siderophore complex. This system has been associated with the ability of V. anguillarum to cause hemorrhagic septicemic disease in marine fish. Recombinant derivatives containing essential regions of the pJM1-mediated iron uptake system cloned into cosmid vector pVK102 were introduced into low-virulence iron uptake-deficient V. anguillarum strains by using a trifactor mating procedure with helper plasmid pRK2013. Three recombinant clones, pJHC-T7, pJHC-T11, and pJHC-T2612, possessed genetic determinants for receptor activity. Production of receptor activity was correlated in all three cases with the presence of OM2, an 86-kilodalton outer membrane protein which was induced under iron-limiting conditions. Two of the clones, pJHC-T7 and pJHC-T2612, also coded for the production of siderophore activity, although at a much lower level than the wild type. Strains harboring either of these two clones were still unable to grow under iron-limiting conditions. This inability was overcome only when other indigenous pJM1 derivatives were present in the cells in addition to the recombinant cosmids. This restoration of high siderophore production and ability to grow under iron-limiting conditions was achieved even when the indigenous plasmids possessed lesions in genes involved in siderophore activity or in both siderophore and receptor production. Thus, another function mediated by plasmid pJM1, possibly a transacting factor, may play a role in the regulation of siderophore production. Results of experimental infections demonstrated that restoration of the ability to grow under conditions of iron limitations by introduction of an recombinant clone into one of the low-virulence V. anguillarum strains was correlated with an increase in bacterial pathogenicity.

Animals↗
PubMed1983

Molecular factors associated with virulence of marine vibrios isolated from striped bass in Chesapeake Bay.

On the basis of cultural and biochemical properties as well as DNA homology assays, 81 Vibrio strains isolated from diseased striped bass and from Chesapeake Bay water were assigned to eight distinct groups. All organisms belonging to two of the groups were pathogenic for striped bass and were identified as Vibrio anguillarum, whereas organisms classified in the other six groups were nonpathogenic and were designated as Vibrio spp. Unlike the pathogenic V. anguillarum strain 775 isolated in the Pacific Northwest, strains pathogenic for striped bass did not contain any plasmids; however, they were similar to the Northwest isolates in that virulence was correlated with their ability to grow in the presence of nonimmune striped bass serum or under conditions of iron limitation. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of outer membranes showed that additional proteins were induced in those organisms capable of growth under conditions of iron limitation. It was of interest that 22 of the nonpathogenic isolates harbored one or more plasmids which, by restriction endonuclease analyses, were shown to be clearly different from the virulence plasmid pJM1.

Animals↗
PubMed1983

Iron uptake system medicated by Vibrio anguillarum plasmid pJM1.

Plasmid pJM1 from an invasive strain of Vibrio anguillarum mediates an iron-sequestering system that is associated with the ability of this bacterium to cause septicemia in marine fishes. This plasmid-mediated iron uptake system was analyzed by using mutations caused by transposon Tnl. Restriction endonuclease analysis of iron uptake-deficient and -proficient derivatives generated by insertion of Tnl and molecular cloning experiments permitted us to localize the plasmid regions involved in the process of iron sequestration to a stretch of about 20 kilobase pairs. In addition, the existence of two plasmid-mediated components involved in the process of iron uptake in V. anguillarum was defined: a diffusible substance which functions as a siderophore and a nondiffusible receptor for complexes of iron-siderophore, which we have tentatively identified as the pJM1 plasmid-mediated outer membrane protein OM2 of V. anguillarum.

Cloning, Molecular↗
PubMed1981

The nucleotide sequence surrounding the replication terminus of R6K.

The replication terminus of the plasmid R6K has been cloned into the single-stranded DNA phage vector M13mp5 and also into the plasmid vectors pBR313 and PBR322. By using single-stranded DNA templates prepared from the recombinant DNA clones, the sequence of 215 base pairs of DNA containing the replication terminus has been determined. The DNA sequence of the region of the terminus does not contain any 2-fold rotational symmetry. Therefore, folding of the DNA at the region of the terminus is unlikely to be a cause for replication termination. Interaction of a host-specified protein(s) with the sequence of the replication terminus is probably the basis of the mechanism of replicaion termination.

Bacterial Proteins↗
PubMed1981

Outer membrane proteins induced under conditions of iron limitation in the marine fish pathogen Vibrio anguillarum 775.

Cells of the marine fish pathogen Vibrio anguillarum 775 harboring a plasmid associated with virulence can grow unaffected in the presence of iron-binding compounds such as transferrin. In contrast, the growth of isogenic plasmidless derivatives is inhibited by the presence of iron chelators. Radioactive from (55Fe3+) uptake experiments indicate that this plasmid-linked ability of V. anguillarum cells to grow under conditions of iron limitation is indeed due to a more rapid and efficient iron uptake mediated by the virulence plasmid. In addition, V. anguillarum cells growing under iron limitation show at least two novel outer membrane proteins. One of them, a 86,000-dalton protein we called OM2, is inducible only in those cells in which the virulence plasmid is present.

Animals↗
PubMed1981

Serum resistance and hemagglutination ability of marine vibrios pathogenic for fish.

Representative strains of marine vibrios pathogenic for fish were shown to be resistant to the bactericidal activity of normal (nonimmmune) rainbow trout (Salmo gairdneri) serum, and loss of this resistance coincided with a marked reduction in virulence. Thermal lability and a requirement for Mg2+, but not for Ca2+, suggested that a mechanism for serum killing was the alternative complement pathway. In the case of Vibrio anguillarum, serum resistance was not coded for by the virulence plasmid pJM1. Additional testing showed that these pathogenic vibrios were able to agglutinate a variety of eucaryotic cells and that selected strains agglutinated trout erythrocytes; however, a correlation between strain virulence and the ability to agglutinate fish erythrocytes was not apparent. Moreover, whereas mannose was found to inhibit the agglutinating activity of several strains, two of the high-virulence strains displayed a transient, mannose-resistant hemagglutinating activity. No relationship between the carriage of pJM1 by the V. anguillarum strains and hemagglutinating activity was demonstrable.

Animals↗
PubMed1980

Three origins of replication are active in vivo in the R plasmid RSF1040.

Replicating DNA molecules of RSF1040, a deletion derivative of the conjugative R plasmid R6K, are cleaved at a single site by the Eco RI restriction endonuclease. Microscopic analysis of Eco RI-cleaved RSF1040 replicative intermediates synthesized in vivo indicates that initiation of replication occurs at three unique sites, ori alpha, ori beta, and ori gamma. The relative frequencies of initiations at these three origins are different from those found in vitro.

DNA Replication↗
PubMed1980

A plasmid associated with virulence in the marine fish pathogen Vibrio anguillarum specifies an iron-sequestering system.

Many of the high-virulence strains of the marine fish pathogen Vibrio anguillarum isolated from epizootics of the widespread fish disease vibriosis, harbour a specific plamid class which is absent from low-virulence strains. Curing experiments have confirmed a link between this specific plasmic class and the ability of V. anguillarum to establish infections. In general, all bacterial virulence factors promote growth in the antagonistic environment of the host defence mechanisms. One line of defence is provided by the proteins transferrin and lactoferrin, which bind iron, rendering it unavailable to pathogens. A mechanism whereby invading bacteria may successfully compete for the otherwise unavailable iron could therefore become crucial in enabling them to proliferate in body fluids and tissues. I report here evidence which shows that the V. anguillarum virulence plasmid specifies a very efficient iron-sequestering system enabling bacteria to survive in conditions of limited iron availability.

Animals↗
PubMed1980

Curing of a plasmid is correlated with an attenuation of virulence in the marine fish pathogen Vibrio anguillarum.

The transposon A sequence Tn1 containing the ampicillin resistance determinants was transposed from RP4 to a plasmid of the marine fish pathogen Vibrio anguillarum. Curing experiments in which plasmid loss was determined by analysis of the segregation of the ampicillin resistance phenotype showed the association of virulence with the specific V. anguillarum plasmid class.

Ampicillin↗
PubMed1979

Deoxyribonucleic acid relationships among members of the genus Aeromonas.

Polynucleotide sequences among 24 motile and 11 non-motile aeromonads were studied by analysis of deoxyribonucleic acid - deoxyribonucleic acid (DNA-DNA) duplexes with endonuclease S1. In addition, DNA base composition (mole % guanine and cytosine (G + C)) and relative genome sizes were determined for selected strains. Large variations in genome size were found and % GC ranged from 57.1 to 62.9%. On the basis of the strains examined, the Genus Aeromonas consists of two genotypically legitimate groups: a diverse group of motile aeromonads, and the genetically more homogeneous non-motile aeromonads, comprising the species Aeromonas salmonicida. Internal homology groups could not be demonstrated within the motile aeromonads, and significant divergence in related sequences was indicated. This diverse motile group forms the single species Aeromonas hydrophila.

Aeromonas↗
PubMed1978

Mobilization of the Escherichia coli plasmid ColE1 (colicin E1) and ColE1 vectors used in recombinant DNA experiments.

The Escherichia coli Co1E1 plasmid, which codes for production of colicin E1, is inherently nontransferable (nonconjugative) by bacterial mating. Co1E1 can be transmitted at mating by a process called mobilization if Co1E1 is coresident with a transfer plasmid. Mobilization is governed in part by a Co1E1 gene called mob. Co1E1 is mob+. Several Co1E1 derivatives employed in recombinant DNA experiments, notably pBR313 and pBR322, are mob-. These cloning vehicles are mobilized at markedly reduced frequency relative to Co1E1. E. coli K12 carrying either pBR313 or pBR322 represents a useful host vector system for recombinant DNA experiments and affords a significant degree of biological containment.

Bacteriocin Plasmids↗