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This study reports biochemical features of a novel esterase of Bacillus sp. HP 96 isolated from Bazangan Lake in Iran. The optimum pH and temperature for 53.4 kDa-purified esterase were 8 and 40 °C, respectively. The HPLC technique was used to examine the main compound produced by the enzyme on nitrophenyl derivatives. Vmax and Km of esterase towards 4-nitrophenyl butyrate (p-NPB) were 75.12 µmol.min−1 mg−1 and 4.66 mM, respectively. Organic solvents (15, 30% v/v) did not have a significant effect on the stability of the purified enzyme. The Bacillus sp. HP 96 esterase showed a high compatibility towards various ionic liquids and detergents. In conclusion, the characterized esterase has potential to be used in detergent formularizations and biotechnological processes under harsh conditions. [ABSTRACT FROM AUTHOR]

The aim of this research was to evaluate the antibacterial activity of the muscle wall extracts of sea cucumber, Stichopus horrens, against Lactococcus garvieae, Streptococcus iniae, Aeromonas hydrophila, and Yersinia ruckeri bacteria in rainbow trout using the disk-diffusion and well-diffusion methods. In this study, nine sea cucumbers (with the mean weight of 1690 ± 12.18 g) were randomly obtained from two locations in Chabahar Bay, Iran in November 2018. The muscle wall of the body was extracted with each of the ethyl acetate, methanol, and acetone organic solvents. The antibacterial activities of extracts were determined. Only the ethyl acetate extracts of S. horrens in the concentrations at 8 and 12 mg/mL had an inhibitory effect on all the examined bacteria. Y. ruckeri and A.hydrophila bacteria were sensitive to the acetone extracts. The best property was recorded with the S.horrens ethyl acetate extracts, with the MIC value of 0.625 mg/mL against S. iniae and L. garvieae. The MIC values ranging from 0.626 to 1.25 mg/mL were also displayed with the acetone extracts against Y. ruckeri and A. hydrophila, respectively. In conclusion, the ethyl acetate extracts of S. horrens displayed the best spectrum of bactericidal effect obtained from four bacteria strains examined. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine common pesticides in raw milk from the industrial cattle houses of Kermanshah region of Iran. A novel, simple, inexpensive, reliable and environmentally friendly method based on continuous sample drop flow microextraction combined with high-performance liquid chromatography-ultraviolet detection was developed. In this technique, a few microliters of organic solvent is transferred to the bottom of a conical test tube and the aqueous solution in form of fine droplets passes through the organic solvent. At this stage, target analytes are extracted into the organic solvent. After extraction, 20 μL of organic solvent was injected into the analytical instrument. Some effective parameters on extraction were studied and optimized. Under the optimum conditions, the calibration graphs are linear in the range of 1–800 µg/L and limits of detection are in the range of 0.3–1.0 µg/L. Repeatability (intra-day) and reproducibility (inter-day) of the method based on five replicate measurements of 100 µg/L of target pesticides were in the range of 2.7–4.1 and 4.3–7.2%, respectively. The enrichment factors and recoveries are in the range of 308–372 and 77–93%, respectively. [ABSTRACT FROM AUTHOR]

Some studies suggest that exposure to industrial solvents can affect blood pressure. The objective of this study was to investigate the effect of a mixture of organic solvents on blood pressure in women working in a pharmaceutical company in Iran. Four hundred and thirty-three women were included in the study. Women working in packing units (group 1) were not exposed to the mixture of organic solvents, women in new laboratory units (group 2) were exposed to the mixture within the permitted range and women working in old laboratory units (group 3) were exposed to the mixture above the permitted limit. We compared systolic and diastolic blood pressures (SBP & DBP) and prevalence of hypertension and pre-hypertension among groups. The results revealed a significant difference in SBP and pre-hypertension (p<0.001) and hypertension (p<0.05) prevalence between the exposed and the control group, but DBP did not differ significantly. Logistic regression analysis showed a significant association between hypertension and exposure to mixed solvents. Odds ratio for hypertension in the group 2 and group 3 (exposed) workers was 2.36 and 3, respectively, compared to controls. Our results suggest that exposure to a mixture of organic solvents may increase SBP and hypertension and pre-hypertension prevalence in drug manufacture workers. Therefore, more attention should be paid to workers that work in such settings by periodically measuring blood pressure and implementing accurate and comprehensive programs to reduce exposure to organic solvents. [ABSTRACT FROM AUTHOR]

Salinivibrio zinc-metalloprotease (SVP) is an enzyme which was isolated from Salinivibrio proteolyticus, a moderately halophilic species from a hypersaline lake in Iran. A195E and G203D mutants were constructed to increase polarity near the active site in order to preserve the hydration layer against organic solvents [dimethylformamide (DMF), methanol, isopropanol and n-propanol]. A268P was constructed to stabilize a surface loop far from the active site and A195E/A268P was constructed to investigate the combined effects of these two mutations. Results showed that relative C50 values of A195E increased to ∼26 and 11% in DMF and methanol whereas an increase of ∼32 and 41% was observed in the presence of isopropanol and n-propanol. The irreversible thermoinactivation rate (ki) for A195E was estimated to be 60 and 130 (×10−3 min−1) in the presence of DMF and n-propanol, respectively, while ki for SVP was 90 and 190 (×10−3 min−1). G203D exhibited similar ki as A195E in the presence of methanol and isopropanol, but the calculated ki in the presence of DMF and n-propanol was 70 and 160 (×10−3 min−1), respectively. A268P and A268P/A195E variants marginally increased the thermoresistance of the enzyme in this condition. [ABSTRACT FROM PUBLISHER]

Abstract: A simple device was developed that makes the use of lighter than water organic solvents feasible in dispersive liquid–liquid microextraction (DLLME) method. In the ordinary DLLME, the fact that a heavier than water organic solvent must be used, to be sedimented at the conical bottom of a centrifuge tube, limits the applications of this method in some extent. In the developed method, a glass tube with a narrow neck is inserted inside the centrifuge tube. After phase separation, the organic solvent is accumulated in the narrow neck of the device and therefore, can be simply collected by a micro-syringe. The DLLME method with the proposed device was tested for the enrichment of glycyrrhizic acid from aqueous extracts of licorice before analysis by a HPLC method. n-Hexanol and acetone were used as the organic and disperser phases, respectively. Effects of pH, salt concentration and phase volumes on the extraction of the analyte were optimized using a central composite (response surface) design. Under the optimized conditions (i.e. pH 1.3, ionic strength 0.2molL−1, n-hexanol 140μL and acetone 0.8mL) an extraction recovery of 104.1 (±5.1)% and an enrichment factor of 54 were obtained. The proposed method was successfully applied for the study of glycyrrhizic acid''s level of licorice roots grown in three regions of Lorestan province, Iran, with different climate conditions. [Copyright &y& Elsevier]

This paper presents the successful design and implementation of several exhaust ventilation systems in a paint manufacturing factory. The ventilation systems were designed based on American Conference of Governmental Industrial Hygienists recommendations. The duct works, fans, and other parts were made and mounted by local manufacturers. The concentrations of toluene and xylene as the common solvents used in paint mixing factories were measured to evaluate the role of ventilation systems in controlling the organic solvents. Occupational exposure to toluene and xylene as the major pollutants was assessed with and without applying ventilation systems. For this purpose, samples were taken from breathing zone of exposed workers using personal samples. The samples were analyzed using Occupational Safety and Health Administration analytical method No.12. The samples were quantified using gas chromatography. The results showed that the ventilation systems successfully controlled toluene and xylene vapors in workplace, air well below the recommended threshold limit value of Iran (44.49 and 97.73 ppm, respectively). It was also discovered that benzene concentration in workplace air was higher than its allowable concentrations. This could be from solvents impurities that require more investigations. [ABSTRACT FROM AUTHOR]