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Biomedical subjects

J Dankert

Publications and source records attributed to J Dankert.

At least 271 records · Page 15Linked to original sources
PubMed1980

Preparation and quantitative determination of antibodies against major outer mambranes proteins of Escherichia coli O26 K60.

Antisera against isolated outer membrane (OM) proteins I and II of Escherichia coli O26 K60 were elicited in rabbits. Antisera obtained after intramuscular administration with Freund's complete adjuvant showed high titres of specific antibodies. Intravenous administration of the same preparations yielded a considerable antibody response against bacterial lipopolysaccharide, a minor contaminant of the protein preparations. Antibody titres against OM proteins I and II, lipopolysaccharide and murein-lipoprotein were determined by the enzyme-linked immunosorbent assay (ELISA) in these sera, and in antisera elicited against whole formaldehyde-fixed bacteria or isolated OM. Comparison of ELISA with single radial immunodiffusion and interfacial immunoprecipitation tests revealed that ELISA was not only the most uniformly applicable, but also the most specific and the most convenient method. In double diffusion tests no cross-reactivity between proteins I and II was seen. Antibodies against proteins I and II, lipopolysaccharide and lipoprotein could be specifically absorbed from the sera with the appropriate antigen preparations. Absorption experiments with intact E. coli O26 K60, Tris/EDTA-sheared bacteria and isolated OM revealed that antibodies against protein I were hardly absorbed at all probably because the antibody, evoked against denatured protein I, did not react with the protein in its native configuration. Antibodies against protein II and lipoprotein were absorbed by intact as well as by sheared bacteria, but to a much greater extent by isolated OM, which indicates that these OM components are accessible from the outside, but that they are situated relatively deep in the OM structure.

Animals↗
PubMed1980

Major outer membrane proteins: common antigens in enterobacteriaceae species.

The major outer membrane (OM) proteins of 23 enterobacterial strains (principally clinical isolates) and five non-Enterobacteriaceae species were investigated by the sodium dodecyl sulphate-polyacrylamide gel immunoperoxidase (SGIP) technique to evaluate antigenic cross-reactivity among these proteins. All enterobacterial strains contained one or more peptidoglycan-associated major OM proteins, cross-reactive with the peptidoglycan-bound protein I of Escherichia coli, and one non-peptidoglycan-bound heat-modifiable protein, cross-reactive with protein II of E. coli. Results indicated that antigenic cross-reactivity of the major OM proteins is a general phenomenon in the family Enterobacteriaceae, independent of any molecular weight variation of the corresponding proteins in different bacterial strains. SGIP experiments carried out with OM preparations of other species showed no cross-reactivity of any of their OM proteins with enterobacterial major OM proteins. The significance of the immunological relatedness of OM proteins for the classification of some Enterobacteriaceae is discussed.

Antigens, Bacterial↗
PubMed1980

Cross-reactivity of major outer membrane proteins of Enterobacteriaceae, studied by crossed immunoelectrophoresis.

Outer membrane fractions were prepared from 11 bacteria in the family Enterobacteriaceae: Escherichia coli serotypes O1K-, O4K2, O26K60, O75K-, and O111K58, Shigella flexneri, Salmonella typhimurium, Klebsiella pneumonia, Serratia marcescens, Proteus vulgaris, Proteus mirabilis, and Providencia stuartii. All strains studied were found to contain one non-peptidoglycan-bound, heat-modifiable outer membrane protein, and one or two peptidoglycan-associated major outer membrane proteins in the 27,000- to 40,000-dalton range. Crossed immunoelectrophoresis using sodium dodecyl sulfate-polyacarylamide gel electrophoresis for separation of the antigens in the first dimension of the procedure was shown to provide a useful model system for studying the antigenic relationships of the major outer membrane proteins in Enterobacteriaceae species. Peptidoglycan-bound major outer membrane proteins of all bacteria studied reacted with antiserum against the purified peptidogylcan-bound matrix protein I of E. coli O26K60 in this system. Non-peptidoglycan-associated proteins of all strains cross-reacted with protein II of E. coli O26K60 in both their unmodified and their heat-modified forms. These results indicate that the genes coding for the major outer membrane proteins in the family Enterobacteriaceae have been well enough conserved during the course of evolution to allow significant antigenic cross-reactivity between the corresponding proteins in different enterobacterial species.

Antigens, Bacterial↗
PubMed1980

Reversal by trypsin of the inhibition of active transport by colicin E1.

The time course for inhibition of proline transport and irreversible loss of cell viability after treatment with colicin E1 was measured as a function of temperature between 13 and 33 degrees C, using a thermostatted flow dialysis system. Complete inhibition of proline transport at 33 and 13 degrees C occurred in 0.5 min and 3 to 5 min, respectively, after addition of colicin E1 at an effective multiplicity of about 4. At these times, the fractional cell survival, assayed by dilution directly from the flow dialysis vessel into trypsin, ranged from 35 to 80%, with viability always greater than 50% at the lower incubation temperatures. Further studies were carried out at 15 degrees C. Complete inhibition of proline transport, which required 2 to 3 min, occurred much more rapidly at 15 degrees C than did the decay of trypsin rescue, which required 10 to 15 min to reach a survival level of 10 to 20%. The direct addition of trypsin to the flow dialysis vessel, after an addition of colicin E1 that caused complete inhibition of proline or glutamine transport, resulted in restoration of net transport. The restored level was typically about 40% of the control rate, and was very similar to the fractional cell viability measured after incubation in trypsin in the same vessel. It is concluded that trypsin can restore active transport to a significant fraction of a cell population in which transport has been initially inhibited by colicin E1.

Biological Transport, Active↗
PubMed1980

A new anaerobic blood culture medium: laboratory evaluation.

A new medium, Diagnostic Anaerobic Growth Medium (DAG) was evolved for the culture of anaerobic bacteria from blood. Redox potential measurements of DAG, in comparison with four other commonly used media (supplemented peptone broth; thioglycollate broth; chopped meat glucose broth; tryptone soya broth) showed that Ecal of DAG medium to be lower than that of the other media tested. The new medium recovered more quickly after addition of blood, to reach "blank" values within 4 h. Growth curves of 21 anaerobic bacteria in DAG medium showed that they all multiplied satisfactorily.

Anaerobiosis↗
PubMed1979

A garment for use in the operating theatre: the effect upon bacterial shedding.

In operating theatres the air is mainly contaminated with bacteria shed from the human skin. The emission of bacteria can be prevented by wearing clothing of impervious material, while normal cotton clothing does not decrease the shedding of bacteria. In this study shedding of viable bacteria from 20 test-persons wearing an operating theatre suit, composed of 65% polyester and 35% cotton (Diolen), was investigated in a test-chamber and compared with that when normal clothing was worn. The use of this operating-theatre suit resulted in a significant reduction (50--75%) in the number of bacteria-carrying particles in the air of the test-chamber and in an operating room when everyone present wore this suit. A combination of the suit with knee-high boots showed a further reduction in the dispersal of colony forming units. The dispersion from female subjects wearing an operating-theatre frock was significantly higher than when wearing an operating-theatre suit.

Adult↗
PubMed1979

The presence of antibody-coated anaerobic bacteria in asymptomatic bacteriuria during pregnancy.

Quantitative anaerobic culture of urine samples obtained from 593 pregnant women by suprapubic bladder aspiration was performed to establish the involvement of anaerobic bacteria in asymptomatic urinary tract infections. The fluorescent antibody (FA) test was applied to the sediments of bladder aspirates to determine the site of infection. Anaerobic bacteriuria (greater than or equal to 10(4) microorganisms/ml of urine) was found in 34 patients, of whom five were FA-positive. These anaerobes were identified as Lactobacillus minutus, Veillonella parvula (two patients). Clostridium putrefaciens, and Peptostreptococcus anaerobius. Aerobic bacteriuria (greater than 10(4) microorganisms/ml of urine) was detected in 27 patients, of whom 13 were FA-positive. In 10 women with mixed aerobic/anaerobic bacteriuria, no FA-positive bacteria were found. The finding of FA-positive anaerobes may indicate that these organisms are involved in silent renal infection.

Adolescent↗
PubMed1979

Antigenic cross-reactivity of major outer membrane proteins in enterobacteriaceae species.

The protein constituents in the outer membrane (OM) of several serotypes of Escherichia coli and some other Enterobacteriaceae cross-reacted antigenically. Solubilized OM preparations of these bacteria were applied in interfacial precipitin tests to antisera elicited in rabbits against whole bacterial cells, absorbed with their appropriate lipopolysaccharide before testing. The resulting immunecomplexes were analysed on polyacrylamide gels. Protein profiles of the immunoprecipitates showed a considerable antigenic cross-reactivity of outer membrane proteins between most E. coli serotypes. Cross-reactivity, though substantially lower, was also found with OM from three other Enterobacteriaceae species, but was not detectable with Pseudomonas aeruginosa OM. When OM preparations were solubilized at room temperature, the peptidoglycan-bound proteins in the molecular weight range 37,000 to 41,000 predominated in the protein profiles of the immunecomplexes. In profiles of immunecomplexes obtained with boiled OM preparations, a heat-modifiable protein (mol. wt 33,000) predominated. The major OM proteins of the Gram-negative bacterium may therefore play a role as common surface antigens of the family of Enterobacteriaceae.

Antigen-Antibody Complex↗
PubMed1979

Volatile fatty acids and aerobic flora in the gastrointestinal tract of mice under various conditions.

Volatile fatty acids are reported to exert a repressive effect upon Enterobacteriaceae and Pseudomonas species in vitro and in vivo in young mice. The mean total volatile fatty acid concentration in the cecal samples of conventional mice fed ad libitum was 81.7 mumol/g (wet weight), which is antibacterial in vitro, and in the rectal samples it was 41.1 mumol/g (wet weight). The mean count of Enterobacteriaceae in the cecum was only 10(2)/g, whereas in the rectum it was 10(5)/g. Volatile fatty acid levels were influenced by food intake and increased to peak levels approximately 6 to 10 h after eating and then declined. In mice fasted for 17 h, the butyric acid concentration was considerably lower and the number of cecal samples positive for Enterobacteriaceae increased. When fasted for 4 days, mice had extremely low cecal and rectal volatile fatty acid concentrations and the Enterobacteriaceae and enterococci counts increased to mean of 2 x 10(6)/g and 3 x 10(6)/g, respectively, in the cecum and to means of 10(7) and 5 x 10(6)/g in the rectum. We conclude that volatile fatty acids are probably one of the many interference mechanisms which are involved with control of the levels of Enterobacteriaceae (and enterococci) in the large intestine of mice.

Aerobiosis↗
PubMed1979

Identification of viridans streptococci on the Minitek Miniaturised Differentiation System.

A total of 227 strains of viridans streptococci were simultaneously identified on the Minitek Miniaturised System (BBL) and by a conventional method according to Colman and Williams. The Minitek discs were each overlaid with a drop of sterile liquid paraffin, and the trays were incubated in GaSPak jars (BBL) with CO2 generator envelopes. Identification was possible three to four days earlier than with the conventional method. The results were found to be in agreement with the conventional method. Compared to the identification schemes of Cowan and Steel and of Facklam, the results were also in good agreement. Minor differences were found in the number of positive and negative results in those reactions that are variable in all three schemes.

Methods↗
PubMed1979

The prevalence of anaerobic bacteria in suprapubic bladder aspirates obtained from pregnant women.

The incidence of asymptomatic bacteriuria due to aerobic, facultative anaerobic and strictly anaerobic bacteria during pregnancy was determined in 185 patients admitted for complications of pregnancy, using suprapubic bladder aspiration. Anaerobic bacterial counts of 103 per ml urine or higher were detected in 6.4 per cent of the specimens. The incidence of anaerobic bacteriuria seems comparable to that of bacteriuria due to aerobic and facultative anaerobic micro organisms. In our group of patients the incidence of the latter was 5.4%. The presence of anaerobic bacteria was not confined to the occurrence of a particular species. Peptostreptococcus species, Veillonella species, Bacteroides species, Eubacterium species, Clostridium species and Bifidobacterium species were isolated from specimens in concentrations of more than 103 per ml. Consequences of asymptomatic bacteriuria during pregnancy are totally uncertain. Further investigation is necessary to obtain insight into the effect of bacteriuria due to anaerobes upon the outcome of pregnancy.

Anaerobiosis↗
PubMed1979

Antimicrobial activity of crude juices of Allium ascalonicum, Allium cepa and Allium sativum.

Crude juices of garlic (Allium sativum), onion (Allium cepa) and shallots (Allium ascalonicum) were tested in an agar diffusion test for their growth inhibitory effect on five gram negative and three gram positive bacterial species and two yeast species. All test organisms were inhibited by garlic juice, whilst onion and shallot juice showed no effect upon gram negative bacteria. Garlic juice was investigated in more detail. Addition of complex-forming agents and organic matter to the crude juice reduced its activity on all test organisms. Volatile substances showed a strong inhibitory activity after exposure for 8 hours or longer at 23 degrees C or 37 degrees C. Minimal inhibition concentrations determined in a dilution test were found to be high for gram negative bacteria and low for both yeast species. The D-values of the different test organisms in undiluted garlic juice were calculated. P. aeruginosa had a very low D-value, whilst the bacteriostatic concentration was high. This indicates a large concentration exponent of crude garlic juice for this organism. The opposite was found for S. aureus. In view of the strong antibiotic properties and the complete absence of development of resistance further investigation upon the principles of the antimicrobial activity of juices from Allium species merits consideration.

Anti-Bacterial Agents↗
PubMed1979

Identification of anaerobes on the Minitek System, compared to a conventional system.

The Minitek Miniaturized System (BBL) was compared to a conventional method (V.P.I.) for the indentification of anaerobes. Anaerobiosis was achieved by using the GasPak system (BBL) and a glove box. Gram staining, colonial morphology, gas-liquid chromatography and biochemical reactions as detailed in the Virginia Polytechnic Institute anaerobe laboratory manual were compared to the biochemical results obtained on the Minitek system. A total of 32 anaerobes was used. The percentage of correlation was an overall 98.2%. Discrepancies were found mostly in the production of indole, the reduction of nitrate, and the hydrolysis of aesculin. A further 95 anaerobes were tested on these three reactions, and found to give an overall agreement of 92.9%. It was found necessary to use some additional tests as well as gas-liquid chromatography for definitive identification. The microsystem was also evaluated as to time saved, cost and ease of use.

Anaerobiosis↗