Evaluation of methicillin resistance by cefoxitin disk diffusion and PBP2a latex agglutination test in mecA-positive Staphylococcus aureus, and comparison of mecA with femA, femB, femX positivities

Methicillin resistance in staphylococci is primarily due to the presence of a mecA gene which encodes the novel penicillin binding protein2a. Some chromosomal factors such as femA and femB also participate in the expression of methicillin resistance. This study was designed to detect methicillin resistance by cefoxitin disk diffusion and penicillin binding protein2a latex agglutination methods, and to compare mecA, femA, femB and femX gene positivities. A total of 60 MRSA isolates were included in the evaluation. PCR analysis showed that all isolates were positive for mecA and femA genes. Seven of these isolates tested negative by the latex agglutination test. Fifteen isolates were positive for femB and 28 isolates for femX gene. This study implicated that for the determination of methicillin resistance, latex agglutination test is the least reliable method when compared to PCR and cefoxitin disk diffusion test. femA gene shows more correlation than femB and femX with methicillin resistance.     

Supramolecular cobalt(II)-pyridine-2,5-dicarboxylate complexes with isonicotinamide, 2-amino-3-methylpyridine and 2-amino-6-methylpyridine: Syntheses, crystal structures, spectroscopic, thermal and antimicrobial activity studies

The mer-[Co(pydca)(H₂O)₃(ina)]·H₂O (1), (2a3mpyH)₂[Co(pydca)₂(H₂O)₂]·2H₂O (2) and (2a6mpyH)₂[Co(pydca)₂(H₂O)₂]·2H₂O (3) complexes (H₂pydca: pyridine-2,5-dicarboxylic acid, ina: isonicotinamide, 2a3mpy = 2-amino-3-methylpyridine and 2a6mpy = 2-amino-6-methylpyridine) were synthesised and characterised by elemental analysis, magnetic and spectroscopic measurements (UV-Vis and IR spectra) and single crystal X-ray diffraction technique. The thermal behaviour of the complexes was also studied by simultaneous thermal analysis techniques (TG, DTG and DTA). In complex 1, Co(II) ion was coordinated by one bidentate pydca, one isonicotinamide and three aqua ligands to generate a CoN₂O₄ distorted octahedral geometry. Complexes 2 and 3 crystallise in the triclinic system and space group and the structures consist of one complex anion [Co(pydca)₂(H₂O)₂]²⁻, two protonated aminomethylpyridinium cations, ampyH⁺ and two crystal water molecules. In the anions, the Co(II) ions have a distorted octahedral configuration and are coordinated by two bidentate pydca and two trans-aqua ligands. The pydca ligand is coordinated to the Co(II) by both the heterocyclic N atom and the adjacent carboxylate group O atom, creating a chelate ring, while protonated ampy ions behave as counter ion.     

Estrogen regulation of nitric oxide and inducible nitric oxide synthase (iNOS) in immune cells: implications for immunity, autoimmune diseases, and apoptosis.

Nitric oxide plays a central role in the physiology and pathology of diverse tissues including the immune system. It is clear that the levels of nitric oxide must be carefully regulated to maintain homeostasis. Appropriate levels of nitric oxide derived from iNOS assist in mounting an effective defense against invading microbes. Conversely, inability to generate nitric oxide results in serious, even fatal, susceptibility to infections. Further, dysregulation or overproduction of nitric oxide has been implicated in the pathogenesis of many disorders, including atherosclerosis, neurodegenerative diseases, inflammatory autoimmune diseases, and cancer. Therefore, depending upon the levels of nitric oxide generated, the potential exists for nitric oxide to behave like a "double-edged" biological sword. Taking these issues into consideration, it is thus pivotal to understand the regulation of nitric oxide. Nitric oxide is regulated by many endogenous factors including hormones such as estrogens. While the effects of estrogen on the generation of nitric oxide in non-immune tissues are relatively well documented, the effect of estrogen on iNOS/nitric oxide in immune cells is only now becoming apparent. Our laboratory has recently shown that estrogen treatment of mice markedly upregulates the levels of iNOS mRNA, iNOS protein, and nitric oxide in activated splenocytes. This upregulation of nitric oxide is in part mediated through interferon-gamma (IFN-gamma), a pro-inflammatory cytokine that is enhanced by estrogen. These findings are important considering that estrogens are not only involved in regulation of normal immune responses, but also are implicated in many autoimmune and inflammatory diseases. To date, there are no reviews on the effects of estrogen on immune tissue-derived nitric oxide and therefore this review will address this critical gap in the literature. Given the increasing importance of immune-tissue-derived iNOS in health and disease, studies on estrogen-induced regulation of iNOS may offer a better understanding of diseases and aid in devising new therapeutic interventions.     

Cloning and expression of the Clostridium thermocellum L-lactate dehydrogenase gene in Escherichia coli and enzyme characterization

The structural gene for L-lactate dehydrogenase (LDH) (EC.1.1.1.27) from Clostridium thermocellum 27405 was cloned in Escherichia coli by screening the Lambda Zap II phage library of C. thermocellum genomic DNA. In one positive clone, an open reading frame of 948 base pairs corresponded to C. thermocellum ldh gene encoding for the predicted 315-residue protein. The ldh gene was successfully expressed in E. coli FMJ39 (ldh mutant) under the lac promoter. The recombinant enzyme was partially purified from E. coli cell extracts and its kinetic properties were determined. Clostridium thermocellum LDH was shown to catalyze a highly reversible reaction and to be an allosteric enzyme that is activated by fructose-1,6-diphosphate (FDP). For pyruvate, partially purified LDH had Km and Vmax values of 7.3 mmol/L and 87 micromol/min, respectively, and in the presence of FDP, a 24-fold decrease in Km and a 5.7-fold increase in Vmax were recorded. The enzyme exhibited no marked catalytic activity for lactate in the absence of FDP, whereas Km and Vmax values were 59.5 mmol/L and 52 micromol/min, respectively, in its presence. The enzyme did not lose activity when incubated at 65 degrees C for 5 min.     

Effects of dietary vitamin E and selenium on antioxidative defense mechanisms in the liver of rats treated with high doses of glucocorticoid

The aim of this work was to determine the effects of dietary intake vitamin E and selenium (Se) on lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and on the antioxidative defense mechanisms in the liver of rats treated with high doses of prednisolone. Two hundred fifty adult male Wistar rats were randomly divided into five groups. The rats were fed a normal diet, but groups 3, 4, and 5 received a daily supplement in their drinking water of 20 mg vitamin E, 0.3 mg Se, and a combination of vitamin E and Se, respectively, for 30 d. For 3 d subsequently, the control group (group 1) was treated with a placebo, and the remaining four groups were injected intramuscularly with 100 mg/kg body weight (BW) prednisolone. After the last administration of prednisolone, 10 rats from each group were killed at 4, 8, 12, 24, and 48 h and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) enzymes and the levels of glutathione (GSH) and TBARS in their livers were measured. GSH-Px, SOD, and CAT enzyme activities and GSH levels in prednisolone-treatment group (group 2) began to decrease gradually at 4 h, falling respectively to 38%, 55%, and 40% of the control levels by 24 h, and recovering to the control levels at 48 h. In contrast, prednisolone administration caused an increase in the hepatic TBARS, reaching up to four times the levels of the control at 24 h. However, supplementation with vitamin E and Se had a preventive effect on the elevation of the hepatic TBARS and improved the diminished activities of the antioxidative enzymes and the levels of GSH. Therefore, the present study demonstrates the effectiveness of vitamin E and Se in reducing hepatic damage in glucocorticoid-treated rats and suggests that reductions in increased TBARS as a result of prednisolone may be an important factor in the action of vitamin E and Se.     

Serum zinc, selenium, copper, and lead levels in women with second-trimester induced abortion resulting from neural tube defects

Neural tube defects are important causes of infant mortality and childhood morbidity. We investigated the relationship between zinc, selenium, copper, and lead concentrations and neural-tube-defect occurrence in women with a second-trimester termination due to fetal-neural-tube defects (NTDs) in this case-control study. Fourteen pregnant women whose pregnancies were terminated as a result of second-trimester ultrasonographic diagnosis of neural tube defects were recruited as cases. The control group (n=14) consisted of women who were selected among age-, gravidity-, and socio-economic-state (SES)-matched women who had a normal triple-screen and targeted ultrasound during the second trimester with documented normal fetal outcome. Zinc and copper determinations were made using flame atomic absorption spectrophotometer (AAS). Graphite furnace AAS was used for Pb, and Se levels were measured with hydride generation AAS. Cases had significantly low serum zinc and selenium levels (62.48±15.9 vs 102.6±23.7 and 55.16±11.3 vs 77.4±5.5, respectively, p<0.001). Serum Cu and whole-blood Pb levels were significantly high when compared to controls. There was a negative correlation between serum zinc and selenium levels, and serum copper levels (r=−425 and −0.443, p<0.05). Our results are consistent with some previous reports. The etiology of NTDs cannot be explained with one strict etiologic mechanism. On the contrary, an interaction among environmental, genetic, and nutritional factors such as trace elements and vitamins would explain these anomalies. If folic acid supplementation is given, additional Zn supplementation should be considered for the further decrease in the recurrence and occurrence of NTDs.     

Facile detection of protein-protein interactions by one-dimensional NMR spectroscopy

Two methods for detecting protein-protein interactions in solution using one-dimensional (1D) NMR spectroscopy are described. Both methods rely on measurement of the intensity of the strongest methyl resonance (SMR), which for most proteins is observed at 0.8-0.9 ppm. The severe resonance overlap in this region facilitates detection of the SMR at low micromolar and even sub-micromolar protein concentrations. A decreased SMR intensity in the 1H NMR spectrum of a protein mixture compared to the added SMR intensities of the isolated proteins reports that the proteins interact (SMR method). Decreased SMR intensities in 1D 13C-edited 1H NMR spectra of 13C-labeled proteins upon addition of unlabeled proteins or macromolecules also demonstrate binding (SMRC method). Analysis of the interaction between XIAP and Smac, two proteins involved in apoptosis, illustrates both methods. A study showing that phospholipids compete with the neuronal core complex for Ca2+-dependent binding to the presynaptic Ca2+-sensor synaptotagmin 1 illustrates the usefulness of the SMRC method in studying multicomponent systems.     

Sporotrichosis Successfully Treated with Terbinafine and Potassium Iodide: Case Report and Review of the Literature

Sporotrichosis is rare in Turkey. We report a 40-year-old woman who had subcutaneous sporotrichosis caused by sporothrix schenckii that was successfully treated with terbinafine (250 mg, twice a day) for a period of 6 months. She received a saturated solution of potassium iodide orally for two months. Terbinafine and potassium iodide are suggested to be the agents of choice for treatment of subcutaneous sporotrichosis.     

fruitless splicing specifies male courtship behavior in Drosophila

All animals exhibit innate behaviors that are specified during their development. Drosophila melanogaster males (but not females) perform an elaborate and innate courtship ritual directed toward females (but not males). Male courtship requires products of the fruitless (fru) gene, which is spliced differently in males and females. We have generated alleles of fru that are constitutively spliced in either the male or the female mode. We show that male splicing is essential for male courtship behavior and sexual orientation. More importantly, male splicing is also sufficient to generate male behavior in otherwise normal females. These females direct their courtship toward other females (or males engineered to produce female pheromones). The splicing of a single neuronal gene thus specifies essentially all aspects of a complex innate behavior.