Production of an extracellular thermohalophilic lipase from a moderately halophilic bacterium, Salinivibrio sp. strain SA-2

Fifty strains of moderately halophilic bacteria were isolated from various salty environments in Iran. A strain designated as SA-2 was shown to be the best producer of extracellular lipase and was selected for further studies. Biochemical and physiological characterization along with 16S rDNA sequence analysis placed SA-2 in the genus Salinivibrio. The optimum salt, pH, temperature and aeration for enzyme production were 0.1 M KCl, pH 8, 35 degrees C and 150 rpm, respectively. The enzyme production was synchronized bacterial growth and reached a maximum level during the early-stationary phase in the basal medium containing 1 M NaCl. Triacylglycerols enhanced lipase production, while carbohydrates had inhibitory effects on it. The maximum lipase activity was obtained at pH 7.5, 50 degrees C and CaCl(2) concentration of 0.01 M. The enzyme was stable at pH range of 7.5-8 and retained 90% of its activity at 80 degrees C for 30 min. Different concentrations of NaNO(3), Na(2)SO(4), KCl and NaCl had no affect on lipase stability for 3 h. These results suggest that the lipase secreted by Salinivibrio sp. strain SA-2 is industrially important from the perspective of its tolerance to a broad temperature range, its moderate thermoactivity and its high tolerance to a wide range of salt concentrations (0-3 M NaCl).     

Association of meteorological factors and seasonality with preeclampsia: a 5-year study in northeast of Iran

Background: Preeclampsia is one of the common causes of maternal and fetal mortality, and an important problem of pregnancy. This disorder can cause intracranial hemorrhage, intravascular coagulation, pulmonary edema, liver and renal failures and placental abruption.

Objective: To evaluate the effects of seasonal and monthly changes of weather, humidity and temperature on the incidence rate of preeclampsia according to the conception and delivery times.

Materials and methods: Retrospective analysis of hospital records of 20?520 consecutive singleton live birth pregnancies of 20–42 weeks of gestation during 2002–2008 was performed. After including preeclamptic cases, on the basis of American College of obstetricians and gynecologists (ACOG) criteria, gestational age and time of conception was estimated and the mean relative temperature and humidity of each month was derived from monthly climatological data collection of IRAN METEOROLOGICAL ORGANIZATION (IRIMO) between 22 June 2002 and 19 March 2008 (68 months). Statistics of each month’s births were registered separately.

Results: Mean maternal age of 262 qualified singleton pregnant women with preeclampsia out of 20?520 deliveries were 26.48 years old and 85.9% of deliveries were done by cesarean section method. Based on time of conception, the highest prevalence was detected in summer, especially in September (11.06875%) and August (10.3053%) and the lowest prevalence was found in winter and early spring, especially in January (5.7552%) and April (5.7252%).

Conclusion: Seasonal (monthly) variations of the weather (humidity and temperature) have a significant impression on preeclampsia prevalence.     

Isolation and characterization of a novel γ‐radiation‐resistant bacterium from hot spring in Iran

30 pure colonies with various colors and shapes were isolated from the samples of water and mud which were collected from the Abe‐Siah hot springs in Ramsar, a city in north of Iran, with high‐level of radiation (up to 4 Gy). Colonies were irradiated by 22 KGy radiations and only one of them survived. The survived bacterium with an optimum growth of 30 to 37 °C, pH 6 to 7, and at minimum of 5% NaCl concentration showed promising characteristics. This strain is aerobic, mesophilic, white colony, with catalase‐positive, oxidase‐negative, non motile, spore forming, rod‐shape and finally Gram positive. Strain Bacillus sp. WHO represented a strain of genus Bacillus megaterium according to a phylogenetic analysis of the 16S rDNA and biochemical features. Its radio‐resistancy was compared with E. coli and B. megaterium which were inactivated in 2 KGy and 5.9 KGy respectively. In order to reveal the mechanisms of this extreme radio‐resistancy and WHO DNA repair system we examined its proteomic map, following γ‐irradiation, using two‐dimensional polyacrylamide gel electrophoresis and silver‐staining. The expression levels of majority number of protein spots showed significant changes under radiation stress. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

National Prevalence of Self-Reported Coronary Heart Disease and Chronic Stable Angina Pectoris: Factor Analysis of the Underlying Cardiometabolic Risk Factors in the SuRFNCD-2011

Background

Coronary heart disease (CHD) is one of the most common causes of mortality worldwide. The national prevalence remains unclear in most of the developing countries.

Behavioral and familial predictors of diabetes mellitus in adults aged 20–69 in Yazd,Iran during 2014–2015

Introduction

The present study aimed to assess the behavioral and familial predictors of diabetes mellitus as well as their interaction in the risk of diabetes mellitus type2.

Optimization of preconcentration procedure using magnetic nanoparticles for the determination of manganese in cereal samples

In the present study, we developed a magnetic nanoparticle adsorbent that uses iron oxide nanoparticles as the core and 1-(2-pyridylazo)-2-naphthol (PAN) as manganese ion exchange groups in cereal samples. This adsorbent was shown to be quick and efficient for the adsorption of manganese due to higher specific surface area, lower mass removal resistance and the absence of internal diffusion resistance. This method is simple and rapid for the preconcentration and determination of manganese in food samples by inductively coupled plasma optical emission spectrometry (ICP OES). The technical feasibility of magnetic nanoparticles for the removal of manganese was investigated under batch studies. It was based on (PAN)-modified magnetic nanoparticles. Four variables (pH of solution, amount of extractant (E), amount of nanoparticles (N) and time) were regarded as factors in the optimization. Results of the two-level fractional factorial design (2^4?1) based on an analysis of variance demonstrated that only the pH, amount of extractant (E) and amount of nanoparticles (N) were statistically significant. Optimal conditions for the extraction of manganese were obtained using Box–Behnken design. For optimum recovery of manganese, the variables pH of solution, amount of nanoparticles and amount of extractant values were 9.44, 3.46 mg and 3.91 mg, respectively. In the optimum experimental conditions, the limit of detection and enrichment factor of the proposed method were 0.1 μg L^?1 and 28, respectively. The precision as RSD was 3.6% for concentration of 50 μg L^?1. The accuracy of the proposed procedure was evaluated by analysis of certified reference material. The method was applied to the determination of manganese in barley, wheat and rice flour samples. The manganese content in the samples analyzed varied from 7.8 to 19.9 μg g^?1.