Antimicrobial susceptibility and pulsed-field gel electrophoresis of Shigella sonnei strains in Malaysia (1997-2000)

AIMS: Antimicrobial resistance of Shigella sonnei from Malaysia was determined and subtyping was carried by pulsed-field gel electrophoresis (PFGE) to assess the extent of genetic diversity of these strains. METHODS AND RESULTS: A total of 62 isolates of S. sonnei from sporadic cases of shigellosis in different parts of Malaysia were studied by antimicrobial susceptibility test and PFGE. Approximately 35.5% of the strains showed resistance to three or more antimicrobial agents. Eight resistant phenotypes, i.e. RI to RVIII, was defined. Resistant phenotype RV and RVIII only appeared in year 2000. PFGE analysis with NotI and XbaI restriction showed that a great heterogeneity existed at the DNA level among Malaysian S. sonnei isolates. Fifty-eight NotI and 61 XbaI-PFGE profiles were observed in 63 S. sonnei isolates, including ATCC 11060 isolate. Drug sensitive isolates displayed very different profiles from drug-resistant isolates, with a few exceptions. Isolates of resistant phenotype RVI (SXTr.TETr.STRr) showed a greater similarity among each other compared with isolates of resistant phenotype RI and drug-sensitive isolates. CONCLUSION: Multi-drug-resistant S. sonnei were circulated in different parts of Malaysia and the emergence of new resistant phenotype was observed. Wide genetic variations among Malaysian S. sonnei were observed and the drug-sensitive strains could be differentiated from drug-resistant strains by PFGE. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study verifies the usefulness of PFGE in characterizing and comparing strains of S. sonnei. Minor variations among S. sonnei isolates could be detected by PFGE.     

Cotton Leaf Curl Virus： Ionic Status of Leaves and Symptom Development

In the present study, the relationship between the nutritional status of leaves and the development of symptoms of cotton leaf curl virus （CLCuV） in two cotton （Gossypium hirsutum L.） cuItlvars （I.e. CIM-240 and S-12） was Investigated. The incidence of disease attack was found to be 100% In the S-12 cuItlvar and 16% in the CIM-240 cuItivar. Geminivirus particles in infected leaves were confirmed by transmission electron microscope examination of highly specific geminivirus coat protein antlsera-treated cell sap. The CLCuV Impaired the accumulation of different nutrients in both cuItivars. A marked decrease in the accumulation of Ca^2＋ and K^＋ was observed in infected leaves. However, the disease had no effect on leaf concentrations of Na^＋, N, and P. It was observed that the curling of leaf margins in CLCuV-Infected plants was associated with the leaf Ca^2＋ content; leaf curling was severe in plants with a significant reduction In Ca^2＋ content. Moreover, leaf K＆＋ content was found to be associated with resistance/susceptibility to CLCuV infection.     

Content and composition of fatty acids in normal and inflamed gingival tissues

The balance of essential fatty acid is important for good health and normal development. Essential fatty acids (EFA) are the precursors of prostaglandins (PGs), thromboxanes and leukotrienes (LT). The aim of this clinical study was to determine the total fatty acid level of polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), saturated fatty acids (SFA) and each fatty acids level of inflamed and normal gingival tissues. Twenty-seven subjects were included the present study. Nineteen samples of inflamed human gingival tissue (nine of fibrous hyperplasia (FH), ten of peripheral giant cell granuloma (PGCG) and eight samples of normal human gingival tissue were analyzed. The characteristics of inflammation were assessed histologically. Variance analyses were performed to assess the differences among tissues. The total cellular fatty acid profiles of the tissues in inflamed human gingival tissue and in eight samples of normal human gingival tissue were determined by gas chromatography using Sherlock microbial identification system (MIS) software (Microbial ID, Newark, DE, USA) with a database of FAME profiles for eukary. PUFAs, MUFAs, and SFAs were quantified by Sherlock microbial identification system (MIS) or database gas chromatography (DGC). There were statistically significant differences between the concentrations in inflamed (FH, PGCG) and healthy gingival tissues for PUFA and MUFA (P<0.001, P<0,011, respectively). There were statistically significant differences among the concentrations in FH, PGCG, and healthy gingival tissues for SFA (P<0.0001). Arachidonic acid, docosahexaenoic acid, linoleic acid were increased in inflamed tissue. The results of this study showed that unsaturated fatty acids (PUFA and MUFA) significantly increased in inflamed gingival tissues.     

Expression and localization of Muc4/sialomucin complex (SMC) in the adult and developing rat intestine: implications for Muc4/SMC function

Muc4/sialomucin complex (SMC) is a high molecular mass heterodimeric membrane mucin, encoded by a single gene, and originally discovered in a highly metastatic ascites rat mammary adenocarcinoma. Subsequent studies have shown that it is a prominent component of many accessible and vulnerable epithelia, including the gastrointestinal tract. Immunoblot and immunofluorescence analyses demonstrated that Muc4/SMC expression in the rat small intestine increases from proximal to distal regions and is located predominantly in cells at the base of the crypts. These cells were postulated to be Paneth cells, based on their location, morphology, and secretory granule content. Immunohistochemistry indicated the presence of Muc4/SMC in these granules. Muc4/SMC expression was higher in the rat colon than small intestine and was abundantly present in colonic goblet cells, but not in goblet cells in the small intestine. Immunohistochemistry also suggested the presence of MUC4 in human colonic goblet cells. Biochemical analyses indicated that rat colonic Muc4/SMC is primarily the soluble form of the membrane mucin. Analyses of Muc4/SMC during development of the rat gastrointestinal tract showed its appearance at embryonic day 14 of the esophagus and at day 15 at the surface of the undifferentiated stratified epithelium at the gastroduodenal junction, then later at cell surfaces in the more distal regions of the differentiated epithelium of the small intestine, culminating in expression as an intracellular form in the crypts of the small intestine at about day 21. Limited expression in the colon was observed during development before birth at cell surfaces, with expression as an intracellular form in the goblet cells arising during the second week after birth. These results suggest that membrane mucin Muc4/SMC serves different functions during development of the intestine in the rat, but is primarily a secreted product in the adult animal.     

Assessment of DNA damage in glue sniffers by use of the alkaline comet assay

Toluene is used widely, not only in industry, but also in households where toluene exposure and abuse can occur. To estimate the genotoxic risk of toluene exposure, DNA damage was determined in peripheral lymphocytes of 20 glue sniffers and 20 age-matched controls by use of the alkaline comet assay. Urinary hippuric acid and o-cresol excretion rates, which are used as a marker for toluene exposure, were also measured in sniffers and compared with historical control values. The increase in genetic damage in sniffers was statistically significant as compared to control subjects (P<0.0001). The mean values of the hippuric acid and o-cresol excretion rate for glue sniffers was 73- and 1582-fold higher, respectively, than in controls and confirms the putative exposure. Education of the general public and efforts to keep adolescents away from volatile solvent-based products, which may lead to a desire of sniffing in the future, would be advisable.     

Cotton Leaf Curl Virus: lonic Status of Leaves and Symptom Development

In the present study, the relationship between the nutritional status of leaves and the development of symptoms of cotton leaf curl virus (CLCuV) in two cotton (Gossypium hirsutum L.) cultivars (i.e. CIM-240 and S-12) was investigated. The incidence of disease attack was found to be 100% in the S-12 cultivar and 16% in the CIM-240 cultivar. Geminivirus particles in infected leaves were confirmed by transmission electron microscope examination of highly specific geminivirus coat protein antisera-treated cell sap. The CLCuV impaired the accumulation of different nutrients in both cultivars. A marked decrease in the accumulation of Ca2+ and K+ was observed in infected leaves. However, the disease had no effect on leaf concentrations of Na+, N, and P. It was observed that the curling of leaf margins in CLCuV-infected plants was associated with the leaf Ca2+ content; leaf curling was severe in plants with a significant reduction in Ca2+ content.Moreover, leaf K+ content was found to be associated with resistance/susceptibility to CLCuV infection.     

Calmodulin kinase II inhibition protects against myocardial cell apoptosis in vivo

Inhibition of the multifunctional Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) or depletion of sarcoplasmic reticulum (SR) Ca(2+) stores protects against apoptosis from excessive isoproterenol (Iso) stimulation in cultured ventricular myocytes, suggesting that CaMKII inhibition could be a novel approach to reducing cell death in conditions of increased adrenergic tone, such as myocardial infarction (MI), in vivo. We used mice with genetic myocardial CaMKII inhibition due to transgenic expression of a highly specific CaMKII inhibitory peptide (AC3-I) to test whether CaMKII was important for apoptosis in vivo. A second line of mice expressed a scrambled, inactive form of AC3-I (AC3-C). AC3-C and wild-type (WT) littermates were used as controls. AC3-I mice have reduced SR Ca(2+) content and are resistant to Iso- and MI-induced apoptosis compared with AC3-C and WT mice. Phospholamban (PLN) is a target for modulation of SR Ca(2+) content by CaMKII. PLN(-/-) mice have increased susceptibility to Iso-induced apoptosis. Verapamil pretreatment prevented Iso-induced apoptosis in PLN(-/-) mice, indicating the involvement of a Ca(2+)-dependent pathway. AC3-I and AC3-C mice were bred into a PLN(-/-) background. Loss of PLN increased and equalized SR Ca(2+) content in AC3-I, AC3-C, and WT mice and abolished the resistance to apoptosis in AC3-I mice after MI. There was a trend (P = 0.07) for increased Iso-induced apoptosis in AC3-I mice lacking PLN compared with AC3-I mice with PLN. These findings indicate CaMKII is proapoptotic in vivo and suggest that regulation of SR Ca(2+) content by PLN contributes to the antiapoptotic mechanism of CaMKII inhibition.