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Biomedical subjects

B Adler

Publications and source records attributed to B Adler.

At least 127 records · Page 7Linked to original sources
PubMed1991

Temperature-regulated expression of invasion genes in Shigella flexneri is controlled through the transcriptional activation of the virB gene on the large plasmid.

The invasion phenotype of shigellae is subject to thermoregulation that is known to be expressed through activation of some invasion (inv) genes such as ipaB, ipaC, and ipaD encoded by the large virulence plasmid of Shigella flexneri. The expression of ipa genes is regulated positively by virF through the activation of virB on the plasmid. To identify the mediator for the thermoregulation of the large plasmid, we have studied the effect of temperature on the transcription of virF and virB genes and ipa and the other two inv operons. The results showed that transcription of virB was affected by temperature more strictly than that of virF. Analysis of the mRNA level of virB at different levels of virF transcription indicated that virB transcription depended upon both temperature and virF. On the other hand, transcriptions of ipa and the other two inv operons depended on the activation of virB transcription but not on temperature. By inducing virB transcription from a tac promoter fused with the virB region, invasion ability was restored to a virF-deletion mutant at 30 degrees C as well as at 37 degrees C. By using conditions in which the temperature-dependent expression of the invasion phenotype was circumvented by the induction of virB transcription, intercellular spreading ability in a virF+, virB::Tn5 strain was shown to be expressed even at 30 degrees C. These results suggest that the virB transcription stage is the main target for the thermoregulation.

Blotting, Northern↗
PubMed1990

Excision of transposon Tn917 in Bacillus subtilis.

Excision of Tn917 from chromosomal sites in B. subtilis is characterized by reversion studies. We propose different modes of excision depending on the site of transposon insertion. Excision takes place as precise excision in one step which results in reversion of the mutant phenotype, or by a two-step process where nearly precise excision of the transposon moiety is followed by precise excision of the nearly precise excision remnants. For this type of transposons a minor pathway or nonreplicative transposition is proposed to be connected with precise excision.

Bacillus subtilis↗
PubMed1990

The distribution and localization of the stage-specific GP31 antigen from infective Ostertagia circumcincta larvae.

The 31,000 mol. wt glycoprotein (GP31) antigen of infective third-stage (L3) Ostertagia circumcincta larvae was shown, by surface labelling experiments and immunofluorescent antibody staining of whole larvae and larval sections, to be distributed internally. When transverse sections of L3 O. circumcincta, taken from the anterior pharyngeal region, were further examined by electron microscopy, after immunogold staining with rabbit anti-GP31 antiserum, the GP31 antigen was found to be specifically located in 'secretory organelles' within the cells of the oesophageal glands. By in vitro culturing L3 O. circumcincta in medium supplemented with 35S-methionine and then analysing the excretory-secretory material released by the larvae, it was found that the GP31 molecule was one of the major components of the excretory-secretory complex. The purified GP31 molecule had no detectable proteolytic activity in protein degradation assays. On examination of Triton X-100 extracts of infective larvae from other nematode parasite species, a predominant antigen similar to GP31 was found in Trichostrongylus colubriformis and Haemonchus contortus, but in Toxocara canis a minor component corresponding in mol. wt to GP31 was also detected. Based on these results the possible role of GP31 as a candidate antigen for a broad spectrum molecular vaccine against gastrointestinal nematode parasites in sheep is discussed.

Animals↗
PubMed1990

Identification and genetic mapping of proteins encoded in the fimbrial subunit gene region of Bacteroides nodosus.

The fimbriae produced by the anaerobic bacterium Bacteroides nodosus are important in the pathogenesis of ovine foot rot. Studies on other microorganisms have shown that the genes coding for the production and assembly of fimbriae are often clustered. By the use of maxicells, transposon mutagenesis and expression vectors, we have identified several genes which are located in the fimbrial subunit gene region. Antiserum was prepared against one of the proteins (88 kDa) which we were able to overproduce in Escherichia coli. In Western blots, these antibodies reacted with an 88 kDa protein located in the B. nodosus cell membrane. However, they did not react with the putative basal protein which is found in fimbrial preparations. We concluded that in B. nodosus the genes involved in fimbrial assembly are not all localised to one small region of the genome. In addition, our studies showed that although the fimbrial subunits are not assembled into intact fimbriae, an N-terminal sequence is processed in E. coli.

Animals↗
PubMed1990

Pasteurella multocida infections in mice with reference to haemorrhagic septicaemia in cattle and buffalo.

Haemorrhagic septicaemia (HS) is an infectious disease of cattle and buffalo caused by particular serotypes of Pasteurella multocida and is one of the most economically important livestock diseases in South-East Asia. While HS has been recognized for many years, very little is understood about the disease, primarily because of the expense of cattle and a lack of suitable animal models. The suitability of using mice to study HS was assessed using parameters such as the critical pathogenic dose, kinetics of infection, pathology of disease and resistance to reinfection. Pasteurella multocida M1404, the type strain for Carter group B, the serotype responsible for Asian HS, was injected intraperitoneally into BALB/c mice. As few as 20 colony forming units produced an overwhelming septicaemia in mice in less than 30 h. The kinetics of infection demonstrated a very rapid in vivo multiplication rate. There was no evidence of inhibition of bacterial cell growth by natural host defence mechanisms, even with the very small inocula used. The gross pathology of the disease in mice was characterized by splenomegaly, lymphadenopathy and petechial haemorrhages similar to that observed in cattle and buffalo with HS. Mice were found to develop a short-lived resistance to reinfection following a primary infection which had been successfully treated with antibiotics. The mouse would seem to provide an ideal tool by which to study HS, but warrant further studies in order to be able to critically assess it as a model for this economically important disease.

Animals↗
PubMed1990

Purification and characterization of a protein antigen from Leptospira interrogans serovar hardjo, common to a wide range of bacteria.

A protein with a molecular mass of 64 kDa (P64) from Leptospira interrogans serovar hardjo was partially purified by using successively, phase partitioning with Triton X-114, ion-exchange chromatography and sucrose gradient centrifugation. Purification to homogeneity was obtained by electroelution of P64 from SDS-polyacrylamide gels. Monospecific rabbit antiserum (R alpha P64) was prepared using the purified protein preparation. P64 had a native molecular mass of greater than 670 kDa and was recognized by R alpha P64 as well as by human antisera. Western blotting of leptospiral serovars and 18 other bacterial species with R alpha P64 showed that P64 was cross-reactive with an equivalent antigen in a wide range of bacteria, indicating that it belongs to a family of antigens previously designated 'common antigen'. This putative common antigen from Leptospira appears to have a sub-surface location, but its function is not yet known.

Animals↗
PubMed1990

Vaccination of mice with lipopolysaccharide (LPS) and LPS-derived immuno-conjugates from Leptospira interrogans.

Mice were vaccinated with lipopolysaccharide (LPS) from Leptospira interrogans serovar pomona or hardjo, or with the polysaccharide (PS) fraction of the LPS, or with an immunoconjugate of PS and diphtheria toxoid (DT). Maximum agglutinin titres were found 6-10 weeks after vaccination with LPS or PS-DT conjugate; the latter elicited antibody titres at least 10 times higher than those produced in response to LPS. Animals failed to react significantly to PS. Titres elicited by antigens of serovar pomona were higher than those elicited by serovar hardjo.

Animals↗
PubMed1990

Epidemiological studies on head lice infestation in Israel. I. Parasitological examination of children.

Of 3,079 children in a medium-sized community near Jerusalem, 11.2% were found to be infested with living lice and eggs and another 23.4% had only nits. Boys and girls were equally infested. The incidence of infestation was highest among children 4-11 years of age. About 78% of the infested children had from one to ten lice. Approximately 80% of the infested children had nits that were 2-5 cm away from the scalp. Boys with medium length hair and girls with short hair showed the highest incidence of lice infestation. Children with brown and red hair were more infested than those with black and blond hair. Boys and girls with straight and wavy hair were more infested than those with curly and frizzy hair.

Adolescent↗
PubMed1990

Antigens recognized by the human immune response to vaccination with a bivalent hardjo/pomona leptospiral vaccine.

Serum from volunteer subjects vaccinated with a bivalent whole cell vaccine of Leptospira interrogans serovar hardjo/serovar pomona grown in protein-free medium, was tested by the microscopic agglutination test (MAT), enzyme-immunoassay (EIA) and immunoblotting. Specific IgM antibodies to either serovars hardjo or pomona were detected in some subjects as early as 6 days after vaccination with peak antibody levels occurring 13-68 days after vaccination. Whereas all subjects produced specific IgM to both serovars, not all produced specific IgG to both serovars. Immunoblotting with hardjo sonicate revealed that all subjects produced IgM antibodies reacting with the 15, 23 and 28 kDa components of hardjo lipopolysaccharide (LPS), and most produced IgM antibodies that reacted with the 34.5 kDa flagellar doublet. In contrast, not all sera immunoblotted against pomona sonicate reacted with the 29 and 35 kDa components of pomona LPS. However all subjects produced antibodies reacting with a diffuse 14.4-27 kDa band. These antibodies appeared early in the immune response. Serum from the one vaccinated subject tested protected hamsters from acute lethal infection with serovar pomona.

Agglutination Tests↗
PubMed1990

The use of car restraints by newborns and mothers: knowledge, attitudes and practices.

Knowledge, attitudes and practices with regard to car safety were studied among 403 parturient women in Jerusalem. The mean knowledge score was 22 out of a total of 32. Attitudes towards seat belt use were positive. Regular use of the seat belt was reported by 36% of the women, but the intent to take the newborn in a car seat for the first ride (from the hospital) was reported by only 8% of the mothers. Knowledge of car safety and mother's seat belt use was significantly associated with the intent of car seat use for the newborn. Sociodemographic variables were not associated with the intent to use a car seat for the newborn. We conclude that laws for mandatory use of seat belts in cities and car restraints for children are needed, and we suggest integration of promotion programs within the existing health services.

Adult↗
PubMed1989

Conversion of a Golgi apparatus sialyltransferase to a secretory protein by replacement of the NH2-terminal signal anchor with a signal peptide.

The beta-galactoside alpha 2,6 sialyltransferase, an integral membrane protein localized to the trans-region of the Golgi apparatus, has been converted into a catalytically active secreted protein by the replacement of the NH2-terminal signal-anchor domain with the cleavable signal peptide of human gamma-interferon. Pulse-chase analysis of the wild type and recombinant proteins expressed in stably transfected Chinese hamster ovary cells showed that the wild type sialyltransferase (47 kDa) remained cell-associated. In contrast, the signal peptide-sialyltransferase fusion protein yielded an enzymatically active 41-kDa polypeptide which was secreted with a half-time of 2-3 h, consistent with cleavage of the signal peptide. The data indicate that the catalytic domain does not contain sufficient information for retention in the Golgi apparatus and that retention signals are likely to be found in the NH2-terminal 57 amino acids of the wild type enzyme.

Animals↗
PubMed1989

Process and outcome evaluation of preventive care for infants in two types of practices.

Process and outcome of preventive and promotive infant care have been evaluated in a maternal and child health (MCH) service and compared with that of a comprehensive care family practice (FP), both serving a low middle class population in West Jerusalem. Both services are provided by the Community Health Center of the Department of Social Medicine. Community oriented primary care is integrated into the practices, including ongoing surveillance of the communities' health status. Preventive and promotive programs have been developed, implemented and evaluated. The process evaluation indicated a similar use of the preventive service in the MCH and FP services. Some of the routines were carried out to a lesser extent in the FP than in the MCH framework, such as growth monitoring, hearing tests and advice on iron supplementation. The small difference in compliance with routines did not affect a child's growth between birth and one year of age, but the anemia rate in the FP practice was higher than in the MCH practice. The high level of care and relatively small differences in process and outcome between the two types of services have been achieved by ongoing inservice training, a high level of personnel, similar protocols and supervision in both practices.

Anemia↗
PubMed1989

Extraction and identification of a 31,000 mol.wt glycoprotein antigen of Ostertagia circumcincta by sera from resistant sheep.

Under similar extraction conditions, Triton X-100 sonicates gave higher yields of protein from third stage larvae and adult O. circumcincta than seven other detergents tested. Using sera from sheep which had been experimentally defined by both immunological and parasitological parameters as being either resistant or susceptible to O. circumcincta, a molecule from Triton X-100 extracts of third stage O. circumcincta larvae was identified which reacted preferentially with sera from resistant sheep. This molecule has a molecular weight of 31,000 and preliminary characterization studies revealed it to be a glycoprotein which was not found in later larval stages or adult worms. Antibodies to this 31,000 mol.wt antigen were present in sera of sheep as early as 3 weeks after experimental infection with O. circumcincta.

Animals↗
PubMed1989

A follow-up study of adiposity and growth of Jerusalem schoolchildren from age 6 to 14 years.

This study evaluated growth and change in adiposity from childhood to early adolescence in 587 Jerusalem schoolchildren examined in both the first and eighth grades. Mean body mass index, height, and weight were determined according to demographic variables and menstrual status and were compared to international reference populations. Menstruating females were taller and heavier than nonmenstruating females at both ages and were more overweight at age 14 years. Height and weight were positively correlated with social class for boys, and few differences were found among ethnic groups. Study subjects were shorter than reference subjects, and study girls were more overweight than reference girls at age 14 years. Our findings suggest that previously demonstrated ethnic differences in growth and adiposity among Israeli children are disappearing. Adolescent girls appear to be at greatest risk for developing obesity. The relationship of pubertal status to body size and obesity at and between the two ages is discussed.

Adolescent↗
PubMed1989

Effectiveness of iron supplementation compared to iron treatment during pregnancy.

This study presents the evaluation of an iron supplementation program in a community by comparing 478 pregnant women who received iron supplementation from the 4th month of pregnancy, with 392 pregnant women who received iron treatment only if their Hb level was less than 12 gm/dl, and had no supplementation. In the supplementation group, no statistically significant associations were found between compliance with age, education, social class or parity. Pregnant women of European-American origin showed higher rates of good compliance than those of Asian-African origin. The mean decrease of haemoglobin (Hb) and haematocrit (Hct) between the second and third trimester of pregnancy was smaller in the supplementation group (-0.9 gm/dl Hb, -2.1% Hct) than in the treatment group (-1.1 gm/dl Hb; -3.3% Hct). The differences between the two groups were significant only for the Hct levels (P = 0.022). The mean Hb and Hct levels during the third trimester of pregnancy were higher for good compliers (11.7 gm/dl Hb; 33.6% Hct) than for poor compliers (11.4 gm/dl Hb, 32.6% Hct).

Adult↗
PubMed1989

Characterization and taxonomic significance of lipopolysaccharides of Leptospira interrogans serovar hardjo.

Lipopolysaccharides (LPSs) from Leptospira interrogans serovar hardjo (reference strain hardjoprajitno and strain hardjobovis) were prepared by the hot phenol-water procedure. High yields of LPSs were found in the phenol phase. Gel electrophoresis of the phenol phase LPSs showed similar patterns for all strains in contrast to the different patterns found in the water phase LPSs. Sugar composition was also similar among all strains with rhamnose as the predominant sugar. Mannosamine was detected by high performance thin layer and gas-liquid chromatography. 2-Keto-3-deoxyoctonic acid (KDO) was comparable with authentic KDO by paper chromatography. Periodate oxidation at near neutral pH with or without prior hydrolysis showed that most of the KDO was substituted. The fatty acid composition of strain hardjobovis LPS was slightly different from that of the reference strain hardjoprajitno. Myristic and 3-hydroxymyristic acid were not detected in any of the LPS preparations. In conjunction with genetic and other data, the two strains are sufficiently different to be regarded as members of two separate species sharing common antigens. There is sufficient evidence to rename the hardjoprajitno strain type L. interrogans hardjo-p, and the hardjobovis strain type L. borgpeterseni hardjo-b.

Carbohydrates↗
PubMed1989

Expression of two conserved leptospiral antigens in Escherichia coli.

The genes encoding two protein antigens of Leptospira interrogans serovar pomona were cloned and expressed in Escherichia coli. Rabbit antisera raised against the cloned proteins, designated p12 and p20, were used to identify the antigens in Western blots of disrupted leptospiral cells. The proteins p12 and p20 were conserved within the genus Leptospira and were not detected in Leptonema illini. Although both proteins were present in leptospiral outer envelope preparations they did not elicit the production of agglutinating or opsonising antibodies.

Agglutination Tests↗