Optimization, characterization, and flow properties of exopolysaccharides produced by the cyanobacterium Lyngbya stagnina.

The exopolysaccharides produced by the cyanobacterium Lyngbya stagnina have been characterized. Maximum amounts of EPS (142.4 µg EPS ml(-1) culture) were obtained during the stationary phase of growth and rate of EPS production was maximum during late phase of growth. When medium was supplemented with 85 mM NaCl, the organism produced three times more EPS compared to EPS produced by control cultures. TLC and HPLC analysis of the EPS hydrolysate revealed heteropolysaccharide nature with presence of four neutral sugars and galacturonic acid. Presence of high amounts of galacturonic acid in EPS indicated its polyanionic character. Aqueous dispersions of EPS showed non-Newtonian, pseudoplastic behavior and its viscosity was found to be quite stable with time. The viscosity data of aqueous dispersions of EPS at different temperatures (20-50 °C) were fitted into rheological models. The viscosity of EPS varied with pH, being highest at pH 10 and lowest at pH 6. Both divalent and monovalent cations caused increase in viscosity of EPS solution. The results suggest that EPS of this organism may find application in food industry.

Prevalence, risk factors, and significance of iron deficiency and anemia in nonischemic heart failure patients with reduced ejection fraction from a Himachal Pradesh heart failure registry.

BACKGROUND: The study aimed to estimate the prevalence, risk determinants, and its clinical significance of iron deficiency and anemia in patients of nonischemic heart failure with reduced ejection fraction (HFrEF). METHODS: Serum ferritin, transferrin saturation, and the hemoglobin (Hb) levels were measured in 226 consecutive patients with HFrEF diagnosed based on the left ventricular ejection fraction ≤ 45% and absence of coronary artery luminal narrowing of more than 50%, in a prospective tertiary care hospital-based heart failure registry. Patients with the New York Heart Association functional class III/IV were classified as patients with advanced heart failure. Multivariable logistic regression modeling was performed to assess the risk determinants of iron deficiency and anemia and their clinical significance as the risk factors for advanced heart failure. Odds ratio with 95% confidence interval (CI) was reported as the estimates of the strength of association between exposure and outcome variables. RESULTS: Iron deficiency and anemia were prevalent in 58.8% (52.2%-65.1%) and 35.8% (29.8%-42.3%) of patients, respectively. Female gender [OR 3.5 (95% CI 1.9-6.5)], history of bleeding [OR 11.7 (95% CI 1.4-101.2)], and vegetarian diet [OR 2.5 (95% CI 1.4-4.6)] were significantly associated with iron deficiency, while diabetes [OR 3.0 (95% CI 1.40-6.5)], estimated glomerular filtration rate [OR 0.98 (95% CI 0.97-0.99)], history of bleeding [OR 13.0 (95% CI 2.3-70.9)], and female gender [OR 2.9 (95% CI 1.5-5.7)] had significant association with anemia. The Hb level (OR 0.82 (95% CI 0.70-0.96) and transferrin saturation (OR 0.98 (95% CI 0.96-0.99)] had a significant inverse association with symptoms of advanced heart failure. CONCLUSION: Iron deficiency and anemia are common comorbidities associated with HFrEF. Low Hb and transferrin saturation are significantly associated with advanced heart failure. The findings have important implications in the management of heart failure.

Measurement of ferrochelatase activity using a novel assay suggests that plastids are the major site of haem biosynthesis in both photosynthetic and non-photosynthetic cells of pea (Pisum sativum L.).

Ferrochelatase is the terminal enzyme of haem biosynthesis, catalysing the insertion of ferrous iron into the macrocycle of protoporphyrin IX, the last common intermediate of haem and chlorophyll synthesis. Its activity has been reported in both plastids and mitochondria of higher plants, but the relative amounts of the enzyme in the two organelles are unknown. Ferrochelatase is difficult to assay since ferrous iron requires strict anaerobic conditions to prevent oxidation, and in photosynthetic tissues chlorophyll interferes with the quantification of the product. Accordingly, we developed a sensitive fluorimetric assay for ferrochelatase that employs Co(2+) and deuteroporphyrin in place of the natural substrates, and measures the decrease in deuteroporphyrin fluorescence. A hexane-extraction step to remove chlorophyll is included for green tissue. The assay is linear over a range of chloroplast protein concentrations, with an average specific activity of 0.68 nmol x min(-1) x mg of protein(-1), the highest yet reported. The corresponding value for mitochondria is 0.19 nmol x min(-1) x mg of protein(-1). The enzyme is inhibited by N-methylprotoporphyrin, with an estimated IC(50) value of approximately 1 nM. Using this assay we have quantified ferrochelatase activity in plastids and mitochondria from green pea leaves, etiolated pea leaves and pea roots to determine the relative amounts in the two organelles. We found that, in all three tissues, greater than 90% of the activity was associated with plastids, but ferrochelatase was reproducibly detected in mitochondria, at levels greater than the contaminating plastid marker enzyme, and was latent. Our results indicate that plastids are the major site of haem biosynthesis in higher plant cells, but that mitochondria also have the capacity for haem production.