Improvement in the Production of L-Lysine by Overexpression of Aspartokinase (ASK) in C. glutamicum ATCC 21799

Purpose: To clone Corynebacterium glutamicum ATCC21799 aspartokinase gene (EC 2.7.2.4) using shuttle expression vector pEKEx2 in order to increase lysine production.Methods: C. glutamicum DNA was extracted and used for amplification of aspartokinase gene (ask) by cloning into an E. coli/C. glutamicum shuttle expression vector, pEKEx2. Initially, the recombinant vector transformed into E. coli DH5á and then into C. glutamicum.Results: Electrophoresis of recombinant protein by SDS-PAGE showed that the molecular weight of the recombinant protein was 42 KD. The induction of recombinant vector by IPTG had an inhibitory effect on cell growth due to over-expression of the cloned gene. The results of lysine assay by Chinard method showed that lysine production increased about two-fold, compared with the parent strain, as a result of increased copy numbers of lysC gene in recombinant strain.Conclusion: A two-fold increase in lysine production was observed by cloning of the ASK gene in C. glutamicum rather than in E. coli, due to the presence of lysine exporter channel which facilitates lysine extraction.Keywords: LysC gene, Corynebacterium glutamicum, L- lysine, Cloning, Aspartokinase, E. col

Population-based incidence of Type 2 diabetes and its associated risk factors: results from a six-year cohort study in Iran

<p>Abstract</p> <p>Background</p> <p>The Middle East is estimated to have the largest increase in prevalence of diabetes by 2030; yet there is lack of published data on the incidence of Type 2 diabetes in this region. This study aimed to estimate Type 2 diabetes incidence and its associated risk factors in an Iranian urban population.</p> <p>Methods</p> <p>Among 3307 non-diabetics ≥ 20 years (mean age 42 ± 13 years, 42% males), glucose tolerance test was performed at baseline in 1999–2001 and at two consecutive phases in 2001–2005 and 2005–2008. Diabetes and glucose tolerance status were defined according to the ADA 1997 criteria. Logistic regression was used to determine the independent variables associated with incident diabetes and their odds ratios (OR).</p> <p>Results</p> <p>After median follow-up of 6 years, 237 new cases of diabetes were ascertained corresponding to an age and sex standardized cumulative incidence of 6.4% (95%CI: 5.6–7.2) and incidence rate of 10.6 (9.2–12.1) per 1000 person years. Besides classical diabetes risk factors, female sex and low education level significantly increased risk of diabetes in age adjusted models. In full model, the independent predictors were age [OR, 95%CI: 1.2 (1.1–1.3)], family history of diabetes [1.8 (1.3–2.5)], body mass index ≥ 30 kg/m²[2.3 (1.5–3.6)], abdominal obesity [1.9 (1.4–2.6)], high triglyceride [1.4 (1.1–1.9)], Isolated impaired fasting glucose (IFG) [7.4 (3.6–15.0)], Isolated impaired glucose tolerance (IGT) [5.9 (4.2–8.4)] and combined IFG and IGT [42.2 (23.8–74.9)].</p> <p>Conclusion</p> <p>More than 1% of the Iranian urban population older than 20 years develops Type 2 diabetes each year. Combination of IFG and IGT was the strongest predictor of incident diabetes among the modifiable risk factors.</p

National and subnational mortality effects of metabolic risk factors and smoking in Iran: a comparative risk assessment

<p>Abstract</p> <p>Background</p> <p>Mortality from cardiovascular and other chronic diseases has increased in Iran. Our aim was to estimate the effects of smoking and high systolic blood pressure (SBP), fasting plasma glucose (FPG), total cholesterol (TC), and high body mass index (BMI) on mortality and life expectancy, nationally and subnationally, using representative data and comparable methods.</p> <p>Methods</p> <p>We used data from the Non-Communicable Disease Surveillance Survey to estimate means and standard deviations for the metabolic risk factors, nationally and by region. Lung cancer mortality was used to measure cumulative exposure to smoking. We used data from the death registration system to estimate age-, sex-, and disease-specific numbers of deaths in 2005, adjusted for incompleteness using demographic methods. We used systematic reviews and meta-analyses of epidemiologic studies to obtain the effect of risk factors on disease-specific mortality. We estimated deaths and life expectancy loss attributable to risk factors using the comparative risk assessment framework.</p> <p>Results</p> <p>In 2005, high SBP was responsible for 41,000 (95% uncertainty interval: 38,000, 44,000) deaths in men and 39,000 (36,000, 42,000) deaths in women in Iran. High FPG, BMI, and TC were responsible for about one-third to one-half of deaths attributable to SBP in men and/or women. Smoking was responsible for 9,000 deaths among men and 2,000 among women. If SBP were reduced to optimal levels, life expectancy at birth would increase by 3.2 years (2.6, 3.9) and 4.1 years (3.2, 4.9) in men and women, respectively; the life expectancy gains ranged from 1.1 to 1.8 years for TC, BMI, and FPG. SBP was also responsible for the largest number of deaths in every region, with age-standardized attributable mortality ranging from 257 to 333 deaths per 100,000 adults in different regions.</p> <p>Discussion</p> <p>Management of blood pressure through diet, lifestyle, and pharmacological interventions should be a priority in Iran. Interventions for other metabolic risk factors and smoking can also improve population health.</p

Effect of Salinity Stress on Seed Quality of Chickpea

A factorial experiment on the basis of RCB design with three replications was conducted in 2007, to investigate the effects of salinity stress (S1, S2 and S3: control, 5 dS/m and 10 dS/m, respectively) on seed quality of three chickpea cultivars (ILC and Jam from kabuli type and Pirooz from desi type) at different stages of development (H1, H2, H3 and H4: 38, 46, 54 and 69 days after flowering). Seed weight, germination percentage and germination rate were significantly affected by salinity and harvest time, but cultivar had only significant effect on seed weight and germination percentage. Comparison of means indicated that 100 seed weight and percentage of germination for ILC and Jam cultivars were statistically similar, but these traits for Pirooz were significantly less than those for two other cultivars. Seeds produced under non-saline conditions (S1) were larger than those produced under low (S2) and high (S3) salinities. Moreover, germination rate and percentage of all seeds decreased, as salinity increased. Seed weight of chickpea increased with progressing seed development. In general, the rate and percentage of germination for all cultivars increased with increasing seed weight. Thus, salinity stress and immaturity can reduce the quality of chickpea seeds

Contrasting styles of convergence in the Arabia-Eurasia collision: Why escape tectonics does not occur in Iran

The westward motion of Turkey relative to Eurasia between the North and East Anatolian faults has been cited as one of the best examples of lateral transport of continental crust from a collision zone, in this case the Arabia-Eurasia collision. This process is variously called "escape" or "extrusion" tectonics. Range-parallel strikeslip faults within the Alborz (e.g., the Mosha fault) and Zagros Mountains (the Main Recent fault) of Iran have been regarded as playing roles similar to those of the North and East Anatolian faults in that they are responsible for the eastward transport of intervening Iranian crust away from the northward motion of the Arabia plate relative to Eurasia. However, both seismicity and GPS data show that there is no net eastward transport of Iranian crust with respect to Eurasia. Here we summarize how the tectonically active mountain ranges of Iran deform by combinations of thrusting and strike-slip movement oblique to the overall convergence vector across each region, without requiring net eastward movement with respect to Eurasia. A general conclusion is that strike-slip faults in collision zones can have different roles. These include not only the lateral transport of crustal material demonstrated in Turkey, but also the partitioning of strain into shortening and strike-slip components shown by the Alborz and Zagros structures and the accommodation of crustal shortening by strike-slip faults that rotate about a vertical axis. © 2006 Geological Society of America