Phospholipase C in Beijing strains of Mycobacterium tuberculosis

Background and Objectives: Phospholipase of Mycobacterium tuberculosis plays an important role in pathogenesis through breaking up phospholipids and production of diacylglycerol. In this study, we examined the Beijing strains of Mycobacterium tuberculosis isolated from Iranian patients for the genes encoding this enzyme. Materials and Methods: DNA extraction was performed using CTAB (cetyltrimethylammonium bromide) from positive culture specimens in tuberculosis patients. PCR was then used to amplify the plcA, plcB, plcC genes of Beijing strain, and non-Beijing strains were identified by spoligotyping. Results: Of 200 specimens, 19 (9.5%) were Beijing strain and 181 (90.5%) were non-Beijing strains. The results of PCR for Beijing strains were as follows: 16 strains (84.2%) were positive for plcA, 17 (89.4%) were positive for plcB and 17 (89.4%) were positive for plcC genes. The standard strain (H37RV) was used as control. Conclusion: The majority of Beijing strains have phospholipase C genes which can contribute to their pathogenesis but we need complementary studies to confirm the role of phospholipase C in pathogenecity of Mycobacterium tuberculosis

Dietary patterns by reduced rank regression predicting changes in obesity indices in a cohort study: Tehran Lipid and Glucose Study

Objective: To examine the association between dietary patterns and obesity indices (BMI, WC, WHR) among Tehranian adults in a 6-year follow-up study. Methods: Within frame of a cohort study in Tehran (mean follow up 6.6±0.9 years), 141 adults were recruited with: two 24 hour dietary recalls at the beginning, as well as obesity indices at the beginning and end of the study period. Dietary intakes were converted into grams of intakes of food items and categorized into 16 groups. Reduced rank regression analysis derived five patterns with total and polyunsaturated-to-saturated fat intake, cholesterol, fiber and calcium intake as response variables. Factors (dietary patterns) were generated retaining a corresponding factor loading � |0.17| on the food groups. Changes in obesity indices were scrutinized within quintiles of factor scores. Results: There were high loadings on refined carbohydrates, whole grain, starchy vegetables, other vegetables, red and refined meat, saturated/trans fat, and egg for the first factor named "traditional". All obesity indices had increasing trend across quintiles of pattern score. The fifth pattern (namely egg pattern) had high loading for eggs, salty snacks, as well as fruits and dry fruits, and negative loadings for red and processed meat, saturated and trans fat, plant oils, and dairy products. This pattern showed increasing trends for WC and WHR after adjustment for potential confounders. Other patterns showed non-significant trends for obesity indices. Conclusions: The results were indicative of a traditional pattern which is dominated in the Tehran region and associated with increase in obesity indices

Tris-chelated complexes of nickel(II) with bipyridine derivatives: DNA binding and cleavage, BSA binding, molecular docking, and cytotoxicity

<p>Two nickel(II) complexes with substituted bipyridine ligand of the type [Ni(NN)₃](ClO₄)₂, where NN is 4,4′-dimethyl-2,2′-bipyridine (dimethylbpy) (<b>1</b>) and 4,4′-dimethoxy-2,2′-bipyridine (dimethoxybpy) (<b>2</b>), have been synthesized, characterized, and their interaction with DNA and bovine serum albumin (BSA) studied by different physical methods. X-ray crystal structure of <b>1</b> shows a six-coordinate complex in a distorted octahedral geometry. DNA-binding studies of <b>1</b> and <b>2</b> reveal that both complexes sit in DNA groove and then interact with neighboring nucleotides differently; <b>2</b> undergoes a partial intercalation. This is supported by molecular-docking studies, where hydrophobic interactions are apparent between <b>1</b> and DNA as compared to hydrogen bonding, hydrophobic, and <i>π–π</i> interactions between <b>2</b> and DNA minor groove. Moreover, the two complexes exhibit oxidative cleavage of supercoiled plasmid DNA in the presence of hydrogen peroxide as an activator in the order of <b>1 </b>><b> 2</b>. In terms of interaction with BSA, the results of spectroscopic methods and molecular docking show that <b>1</b> binds with BSA only via hydrophobic contacts while <b>2</b> interacts through hydrophobic and hydrogen bonding. It has been extensively demonstrated that the nature of the methyl- and methoxy-groups in ligands is a strong determinant of the bioactivity of nickel(II) complexes. This may justify the above differences in biomolecular interactions. In addition, the <i>in vitro</i> cytotoxicity of the complexes on human carcinoma cells lines (MCF-7, HT-29, and U-87) has been examined by MTT assay. According to our observations, <b>1</b> and <b>2</b> display cytotoxicity activity against selected cell lines.</p> <p></p> <p>Communicated by Ramaswamy H. Sarma</p