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J D Oliver

Publications and source records attributed to J D Oliver.

At least 73 records · Page 4Linked to original sources
PubMed1991

Electrophoretic analysis of lipopolysaccharide isolated from opaque and translucent colony variants of Vibrio vulnificus using various extraction methods.

Lipopolysaccharides (LPS) from an opaque and a translucent colony variant of Vibrio vulnificus were isolated by several methods and the electrophoretic profiles were analysed. The phenol-water extraction method provided a better yield compared to the phenol-chloroform-petroleum ether method. In addition, two rapid micro-assays were used to isolate LPS for electrophoretic analysis. The electrophoretic pattern was the same for all LPS extracts and was similar in both variants. No high molecular weight bands, characteristic of smooth LPS, were detected in the LPS of this organism. This was in contrast to the smooth nature of the LPS of another member of the Vibrionaceae examined, V. cholerae. The result of this study showed no correlation between LPS and colony morphology in V. vulnificus.

Electrophoresis, Polyacrylamide Gel↗
PubMed1990

Regulation of lipoprotein lipase activity and mRNA content in rat epididymal adipose tissue in vitro by recombinant tumour necrosis factor.

Tumour necrosis factor (TNF) has previously been shown to decrease lipoprotein lipase (LPL) activity and mRNA levels in 3T3-L1 cells and in adipose tissue from rats and guinea pigs when injected in vivo, but not to alter LPL activity in human adipocytes incubated in vitro. The effect of recombinant human TNF on LPL activity and mRNA levels in rat epididymal adipose tissue incubated in vitro was examined. LPL activity and mRNA levels fell in adipose tissue taken from fed rats and incubated in Krebs-Henseleit bicarbonate medium with glucose. The addition of insulin and dexamethasone prevented these falls. TNF (400 ng/ml) produced a fall of approx. 50% in LPL activity after 2 h of incubation and of approx. 30% in LPL mRNA levels after 3 h. TNF did not decrease LPL activity in isolated adipocytes. These results demonstrate that rat adipose tissue incubated in vitro is responsive to TNF whereas isolated adipocytes are not.

Adipose Tissue↗
PubMed1990

Effects of engineered salt bridges on the stability of subtilisin BPN'.

Variants designed using PROTEUS have been produced in an attempt to engineer stabilizing salt bridges into subtilisin BPN'. All the mutants constructed by site-directed mutagenesis were secreted by Bacillus subtilis, except L75K. Q19E, expressed as a single variant and also in a double variant, Q19E/Q271E, appears to form a stabilizing salt bridge based on X-ray crystal structure determination and differential scanning calorimeter measurements. Although the double mutant was found to be less thermodynamically stable than the wild-type, it did exhibit an autolytic stability about two-fold greater under hydrophobic conditions. Four variants, A98K, S89E, V26R and L235R, were found to be nearly identical to wild-type in thermal stability, indicative of stable structures without evidence of salt bridge formation. Variants Q271E, V51K and T164R led to structures that resulted in varying degrees of thermodynamic and autolytic instability. A computer-modeling analysis of the PROTEUS predictions reveals that the low percentage of salt bridge formation is probably due to an overly simplistic electrostatic model, which does not account for the geometry of the pairwise interactions.

Bacillus subtilis↗
PubMed1990

Phenotypic evaluation of acapsular transposon mutants of Vibrio vulnificus.

Translucent, avirulent spontaneous phase variants of Vibrio vulnificus MO6-24 reverted back to the original opaque, encapsulated phenotype under both in vivo and in vitro conditions. Two translucent, acapsular mutants, which did not show phase variation, were constructed by using the transposon Tn5 IS50L::phoA (TnphoA). Loss of capsule was accompanied by decreases in virulence, hydrophilicity, and serum resistance. The ability to utilize transferrin-bound iron for growth was lost in only one of the two unencapsulated mutants. Our data emphasize the apparent importance of capsule in the virulence of V. vulnificus and indicate that utilization of transferrin-bound iron is independent of encapsulation.

Animals↗
PubMed1990

Studies on the lipopolysaccharide of a virulent and an avirulent strain of Vibrio vulnificus.

Vibrio vulnificus is a marine bacterium associated with both primary septicemias and wound infections in humans. The lipopolysaccharides of a virulent and an avirulent strain of Vibrio vulnificus were compared with respect to their chemical constituents and electrophoretic characteristics. 2-Keto-3-deoxyoctonic acid, a normal constituent of the lipopolysaccharide of typical Enterobacteriaceae, was not found in the lipopolysaccharide of either strain. Hexadecenoate (C16:1) was the predominant fatty acid of the lipid A moiety of the lipopolysaccharides and of the membrane phospholipids of both strains. Hydroxy fatty acids composed 44% of the total fatty acids of the lipid A of the avirulent and 40% of those in the virulent strain. In addition, odd-numbered fatty acids were detected in both lipopolysaccharides. The electrophoretic profile was similar for both strains, but demonstrated no "ladder-like" pattern characteristic of "smooth" lipopolysaccharides. The result of this study showed no significant differences between the lipopolysaccharides of the virulent and avirulent strains of Vibrio vulnificus. The possible role for lipopolysaccharide in pathogenesis of Vibrio vulnificus infections is discussed.

Antigens, Bacterial↗
PubMed1989

Membrane fatty acid and virulence changes in the viable but nonculturable state of Vibrio vulnificus.

The nonculturable state of Vibrio vulnificus and, for comparison, that of Escherichia coli were studied in artificial-seawater microcosms at 5 degrees C. Total cell counts were monitored by acridine orange epifluorescence, metabolic activity by direct viable counts, and culturability by plate counts on selective and nonselective media. Whereas total counts remained constant, plate counts of V. vulnificus suggested nonculturability by day 24. In contrast, direct viable counts indicated significant cell viability throughout 32 days of incubation. As an indication of the metabolic changes that occurred as cells entered the state of nonrecoverability, membrane fatty acid analyses were performed. At the point of nonculturability of V. vulnificus, the major fatty acid species (C16 and C16:1) had decreased 57% from the T0 level, concomitant with the appearance of several short-chain acids. Although the bacteria were still recoverable, a similar trend was observed with E. coli. Electron microscopy of nonculturable V. vulnificus showed that the cells were rounded and reduced in size and contained fewer ribosomes. Mouse infectivity studies conducted with these cells suggested loss of virulence.

Cell Membrane↗
PubMed1989

Comparison of Alternaria tenuis extracts prepared from different raw materials.

Alternaria extracts, prepared from three different sources under the same conditions, were compared by several biochemical/immunochemical methods. Two raw materials (A,G) contained mostly mycelia. The third raw material (C) contained mycelia (35%) and spores (65%). Extracts A and G were different in total allergenic potency, antigen/allergen pattern, and in the Alt 1 content. Extract C was of similar total allergenic potency as extract A but showed a somewhat different antigen/allergen pattern and a different Alt 1 content. Although there were some compositional differences among the extracts, all extracts regardless of source materials (spores and mycelia) demonstrated strong RAST inhibition activity and parallelism of the inhibition curves.

Allergens↗
PubMed1989

(Radio) rocket immunoelectrophoresis a useful screening method for house dust extracts.

House dust (HD) extracts prepared from HD collected in households from West Germany, USA, and Spain were investigated by (radio) rocket immunoelectrophoresis. By pouring agarose gels containing different antisera side by side in strips onto a glass plate, the antigen/allergen components of HD extracts could be detected simultaneously in one electrophoretic separation. In addition to mite and animal dander, antigens/allergens of pollens, mold and food (ovalbumin and cow serum) could be detected in most of the extracts.

Allergens↗
PubMed1988

Vibrio parahaemolyticus (Kanagawa-negative) wound infection in a hospital dietary employee.

Vibrio parahaemolyticus is an estuarine bacterium that is a major cause of gastroenteritis worldwide. Occasionally, this organism has also been shown to be the causative agent of wound infections. In almost all cases of gastrointestinal disease only strains that produce hemolysin ("Kanagawa-positive") are implicated. We have isolated a Kanagawa-negative strain of V. parahaemolyticus from serous wound drainage of the infected foot of a hospital dietary employee. To our knowledge, this is only the third documented case of wound infection caused by such an organism. In this instance, the potential threat of nosocomial transmission was of special concern in that the wound infection was present in a hospital food handler.

Adult↗
PubMed1988

Wound-dynamic studies in Australia.

As part of the Australian programme of studies in wound ballistics, a facility has been developed at the Materials Research Laboratories, Melbourne, Victoria, in which the phenomena associated with the penetration of bullets through tissue simulants can be investigated. This paper outlines the development programme and describes a recent series of comparative firings of 7.62-mm and 5.56-mm ammunition into gelatin tissue simulant.

Australia↗
PubMed1988

Ability of Vibrio vulnificus to obtain iron from hemoglobin-haptoglobin complexes.

It has been suggested that the normal serum protein, haptoglobin (Hp), serves a bacteriostatic role by binding free hemoglobin (Hm), thus making heme iron unavailable for bacterial growth. Previous studies showed that, unlike Escherichia coli, Vibrio vulnificus was able to overcome this Hp-blocking effect. We report here a study on the iron-withholding property of the three major human Hp phenotypes, Hp 1, 2, and 2-1. Results of experiments with human serum showed that V. vulnificus C7184 was able to obtain iron from Hm bound to Hp types 1 and 2, but not that bound to Hp 2-1. E. coli 2395-80, on the other hand, was unable to overcome the blocking effect of any Hp phenotype. Using purified Hp 1, we also demonstrated that, although V. vulnificus was unable to grow in a deferrated medium without an additional iron source, it was able to grow with the addition of the Hm-Hp complex.

Haptoglobins↗
PubMed1988

Burkitt's-like lymphoma of T-cell type.

Over an 8-yr period, we studied 29 cases of Burkitt's/Burkitt's-like lymphoma and unexpectedly found 2 Burkitt's-like cases of the T-cell type. One case presented as diffuse adenopathy in a 35-yr-old male. A second case presented as a jaw mass in a 2-yr-old girl with Down's syndrome. Histologically, each case demonstrated usual Burkitt's-like morphology (intermediate-size cells with high nuclear/cytoplasmic ratio, 1 to 3 prominent nucleoli, high mitotic rate, basophilic cytoplasm, and cytoplasmic vacuolation). Ultrastructural morphometric data corroborated the Burkitt's-like nature of these neoplasms. Immunologically, the neoplasms were of "novel" T-cell phenotype, as seen in peripheral T-cell lymphoma (PTL). The cases showed variable expression of activation antigens (e.g., Ia) and weak to moderate expression of proliferation antigens as measured by Ki-67. This modest proliferative activity (less than 25% Ki-67 expression) contrasts with Burkitt's-like lymphomas of the B-cell type which usually show greater than 80% Ki-67 expression. The jaw tumor also demonstrated positivity for human progenitor cell antigen (HPCA) as commonly found in leukemia. Both cases mimic granulocytic sarcoma by virtue of their eosinophilic/myelocytic recruitment--a phenomenon previously reported in association with PTL. The patients have survived 62 wk and 20 wk, respectively, surpassing the survival rates seen in our concurrent B-cell Burkitt's-like lymphomas (12 wk). Burkitt's-like lymphoma of the T-cell type appears to be a distinctive immunological subset of potential clinical and prognostic relevance.

Adult↗
PubMed1987

Identification of environmental Vibrio vulnificus isolates with a DNA probe for the cytotoxin-hemolysin gene.

We screened 44 lactose-positive Vibrio strains isolated from the marine environment for homology with a 3.2-kilobase DNA fragment encoding the Vibrio vulnificus cytotoxin-hemolysin gene. All 29 marine isolates identified as V. vulnificus on the basis of numerical taxonomy and DNA-DNA hybridization studies hybridized with the cytotoxin gene probe, as did all V. vulnificus reference strains. Homologous gene sequences were identified in no other lactose-positive marine vibrio isolates nor in 10 other Vibrio species.

Animals↗
PubMed1987

New selective and differential medium for Vibrio cholerae and Vibrio vulnificus.

Thiosulfate-citrate-bile salts-sucrose agar has been routinely used for the isolation of pathogenic vibrios, although its selectivity for Vibrio cholerae and Vibrio vulnificus is inadequate. Therefore, a new plating medium, cellobiose-polymyxin B-colistin agar, was developed for the isolation of these two species. Cellobiose-polymyxin B-colistin agar demonstrated a significant advantage over other media designed for the isolation or differentiation of vibrios: of both the 136 strains representing 19 Vibrio species and the marine isolates of the genera Pseudomonas, Flavobacterium, and Photobacterium, only V. vulnificus and V. cholerae were able to grow. Furthermore, the fermentation of cellobiose by V. vulnificus allowed for the easy differentiation of these two species. This medium offers significant potential as a selective and differential medium for these two pathogenic vibrios.

Culture Media↗
PubMed1987

Correlation between virulence and colony morphology in Vibrio vulnificus.

Of 38 isolates of Vibrio vulnificus examined, all avirulent strains produced only translucent colonies. All virulent strains, with the exception of biogroup 2 (eel pathogens), exhibited both opaque and translucent colonies. Isogenic morphotypes were examined for a variety of phenotypic and virulence traits. Only the ability to utilize transferrin-bound iron and the presence of a surface polysaccharide were found to correlate with colony opacity and virulence.

Iron↗
PubMed1987

Allergenic activity of short ragweed pollen (Ambrosia elatior) from different years and/or suppliers: criteria for the selection of an in-house allergen reference preparation.

We have investigated dialyzed extracts (A-F) of short ragweed pollens (Ambrosia elatior) from six consecutive production years and four different companies by protein nitrogen units, high performance liquid chromatography, isoelectric focusing, SDS-PAGE, RAST inhibition, crossed radioimmunoelectrophoresis, and antigen E contents. Extract A showed lowest yields in all quantitative assays. Isoelectric focusing, SDS-PAGE, crossed immunoelectrophoresis, and crossed radioimmunoelectrophoresis showed comparable patterns for all extracts except for extract A. Apparently, the activity of short ragweed pollens depends on the year of production and/or the skill of the producer. These findings are in contrast to similar examinations of other pollen species.

Allergens↗
PubMed1986

Production of extracellular enzymes and cytotoxicity by Vibrio vulnificus.

Thirty-three strains of Vibrio vulnificus of clinical and environmental origin were examined for production of 12 extracellular enzymes of potential importance to the virulence of this bacterium. Strains of Vibrio vulnificus were consistent in their production of protease, mucinase, lipase, chondroitinase, hyaluronidase, DNase, sulfatase, and hemolysin. No differences between clinical and environmental isolates were noted. Although none of the enzymes appeared to correlate with the ability of these strains to produce lethality in mice, the production of hemolysin and of a protease with activity against native serum albumin may be significant in the pathogenesis of the potentially fatal infections produced by this organism. The production of several of these exoenzymes also appeared to correlate with pathogenicity in the seven other Vibrio species examined. Culture filtrates of all virulent strains of Vibrio vulnificus were cytotoxic for Chinese hamster ovary cells, whereas those of the strains of Vibrio parahaemolyticus and Vibrio alginolyticus examined lacked this activity.

Animals↗