Characterization of bioflocculants produced by bacteria isolated from crude petroleum oil

The aim of this study was to look for high efficient bioflocculant-producing microorganisms. Among 36 bacterial colonies isolated from a crude petroleum oil sample, three of them CPO8, CPO13 and CPO14 exhibited flocculation activity exceeding 90% after 3 days of cultivation. They were identified by 16S rDNA sequence analysis as Bacillus subtilis [CPO8, CPO13] and Pseudomonas sp. [CPO14]. Spectroscopic analysis of the polymers by nuclear magnetic resonance [1H NMR] and Fourier-transform infrared [FT-IR] revealed that the polymers were glycoproteins. These polymers were soluble in water and insoluble in any organic solvents tested. The effects of bioflocculant dosage, temperature, and pH on the flocculation activity were evaluated. The maximum bioflocculation activities were observed at an optimum bioflocculant dosage of 3.5 mg/l [strains CPO8 and CPO13] and 5.0 mg/l [strain CPO14], respectively. In addition, these biopolymers were able to flocculate kaolin suspension [5 g/l] over a wide range of pH [pH 3-9] and temperature [5-50 °C] tested in the presence of CaCl2. The highest flocculation activities of strains CPO8, CPO13 and CPO14 were 96.03%, 92.17% and 97.59%, respectively in the early stationary phase [at 24 h], while the cell production reach its maximum in the stationary phase [at 72 h]. Their efficient flocculation capabilities suggest potential applications in industries

Impact of leptin levels upon left ventricular structural abnormalities in non-insulin-dependent diabetics

Non-insulin-dependent diabetes mellitus adversely affects left ventricular [LV] structure. ri.ecent studies have shown that leptin increases in insulin-resistant states, such as obesity and hypertension. The levels of plasma leptin have been found to be associated with LV myocardial growth.To assess fasting serum leptin concentrations in the type 2 diabetic patients and to correlate its level with the LV structural changes. Patients and Twenty four type 2 diabetic patients with LV structural changes and twenty four type 2 diabetic patients without LV structural changes [controls] participated in this study. The following LV structural parameters were assessed by Two-dimensional echocardiography: left ventricular end-diastolic diameter [LVEDD], left ventricular end-systolic diameter [LVESD], interventricular septal thickness [IVST], left ventricular posterioi wall thickness [PWT], relative wall thickness [RWT] and left ventricular mass index [LVMI]. left atrium [LA] and aortic root [Ao] dimensions were also assessed. Fasting serum leptin, insulin, glucose and glycosylated hemoglobin [HbAlc] were determined. The correlations of eptin to LV structural parameters were statistically analyzed. Body mass index [BMI], FBG and fasting serum concentrations of leptin and insulin were significantly greater in patients than controls. There were statistically significant differences between the two groups in all echocardiographic parameters apart from LVEDD, LVESD, RWT, LA and AO In the case group, leptin was positively correlated with FBG and insulin. A significant correlation was also found between serum leptin and echocardiographic parameters; PWT. IVST, SWI and LVMI. Hyperleptinemia in type 2 diabetic patients with LV structural changes and the association of leptin with indexes of LV structure may reflect its role in the development of myocardial wall thickening in non-insulin dependent diabetes mellitus

Biosynthesis of biodegradable polyhydroxyalkanotes biopolymers in genetically modified yeasts

In the recent decade, biosynthesis of the degradable biopolymers polyhydroxyalkanotes in transgenic yeasts became an important research task. Most research strategies depend on either metabolic engineering or molecular approaches. In the present work, research compared PHA biosynthesis in two types of yeasts; Saccharomyces cerevisiae and a non-convenient Kloeckera spp. Yeast strains were equipped in their cytoplasm with thephaABCRe operon containing genes phbA, phbB and phbC of the PHA biosynthetic pathway of Ralstonia eutropha, which encode p-ketothiolase, NADPH-linked acetoacetyl-CoA reductase and PHA synthase, respectively. The transgenic strains Saccharomyces cerevisiae and Kloeckera sp. were able to produce PHA. The maximum content of the polymer detected in the recombinant strain INVScl/PHAl was 2.68% and only poly-3-hydroxybutyrate [PHB] accumulated. However, the non-conventional transgenic strain KY1/PHA was able to accumulate as maximum of 7.06% of the copolymer poly-[3-hydroxybutyrate-co-poly-3-hydroxyvalerate[[PHV]. Western blot analysis confirmed expression of the phaABC[RE] operon in the transgenic yeast strains. The nature of the PHA thus produced by all tested strains was analyzed by [1]H and [13]C nuclear magnetic resonance [NMR] spectroscopy