Effect of Supplementation of Vitamin C and Thiamine on the Outcome in Sepsis: South East Asian Region

Introduction: The global burden of sepsis is overwhelming and novel therapeutic agents is the need of the hour. The present study was designed to understand the role of Malondialdehyde as a marker of the oxidative stress in sepsis, as well as the effect of supplementation of Vitamin C and Thiamine in patients of sepsis. Methods: 80 patients of sepsis were randomly divided into 4 groups of 20 each. Twenty age-sex matched healthy volunteers were chosen as controls. The first group received Vitamin C, the second group received Thiamine, the third group received both and the fourth group received neither. Vitamin C (2g 8 hourly) and Thiamine (200 mg 12 hourly) were given intravenously for five days. The outcome was recorded in terms of mortality in the various groups as well as by the improvement in SOFA scores (?SOFA). The serum levels of Vitamin C, Thiamine and Malondialdehyde were estimated. Results: Among the 80 patients, 17 (21%) were in septic shock. The mortality rate was 10% overall, and 47% among patients of septic shock. No additional mortality benefit was observed in the groups supplemented with Vitamin C and Thiamine. However, the ?SOFA score in patients who received both Vitamin C and Thiamine was significantly higher as compared to the other groups. The mean malondialdehyde level was higher in patients of sepsis (1.81±1.18 ?mol/l) as compared with healthy controls (0.78 ± 0.36 ?mol/l). The Vitamin C level and Thiamine level (estimated indirectly by TPP effect), at presentation were 5.14±4.19 ng/ml and 52.99±28.45 % in patients of sepsis, which was significantly lower than that in healthy controls, in whom the levels were 14.64±5.51 ng/ml and 27.55±13.67% respectively. Conclusion: Vitamin C and Thiamine supplementation is a cost-effective approach with a good safety profile. Additional studies including a larger population is required to study the mortality benefits and reaffirm our findings.

Diversity and seasonal fluctuation of predominant microbial communities in Bhitarkanika, a tropical mangrove ecosystem in India

Different groups of microorganisms are present in mangrove areas, and they perform complex interactions for nutrient and ecological balances. Since little is known about microbial populations in mangroves, this study analyzed the microbial community structure and function in relation to soil physico-chemical properties in Bhitarkanika, a tropical mangrove ecosystem in India. Spatial and seasonal fluctuations of thirteen important groups of microorganisms were evaluated from the mangrove forest sediments during different seasons, along with soil physico-chemical parameters. The overall microbial load (x10(5)cfu/g soil) in soil declined in the order of heterotrophic, free living N2 fixing, Gram-negative nitrifying, sulphur oxidizing, Gram-positive, spore forming, denitrifying, anaerobic, phosphate solubilizing, cellulose degrading bacteria, fungi and actinomycetes. Populations of the heterotrophic, phosphate solubilizing, sulphur oxidizing bacteria and fungi were more represented in the rainy season, while, Gram-negative, Gram-positive, nitrifying, denitrifying, cellulose decomposing bacteria and actinomycetes in the winter season. The pool size of most of other microbes either declined or maintained throughout the season. Soil nutrients such as N, P, K (Kg/ha) and total C (%) contents were higher in the rainy season and they did not follow any common trend of changes throughout the study period. Soil pH and salinity (mS/cm) varied from 6-8 and 6.4-19.5, respectively, and they normally affected the microbial population dynamics. Determination of bacterial diversity in Bhitarkanika mangrove soil by culture method showed the predominance of bacterial genera such as Bacillus, Pseudomonas, Desulfotomaculum, Desulfovibrio, Desulfomonas, Methylococcus, Vibrio, Micrococcus, Klebsiella and Azotobacter. Principal component analysis (PCA) revealed a correlation among local environmental variables with the sampling locations on the microbial community in the mangrove soil. Rev. Biol. Trop. 60 (2): 909-924. Epub 2012 June 01.

En las zonas de manglares están presentes diferentes grupos de microorganismos, los cuales presentan complejas interacciones que afectan los balances ecológicos y de nutrientes. Debido a que se sabe poco sobre las poblaciones microbianas en los manglares, este estudio analiza la estructura y función de la comunidad microbiana según las propiedades físico-químicas del suelo en Bhitarkanika, un ecosistema de manglares tropicales en la India. Se evaluaron las fluctuaciones espaciales y temporales de 13 grupos de microorganismos importantes en el sedimento de los manglares durante diferentes temporadas y parámetros físico-químicos del suelo. La carga microbiana total (x10(5)cfu/g de suelo) en el suelo se redujo en la categoría de las heterotróficas, de las bacterias libres fijadoras de N2, Gram-negativas nitrificantes, oxidativas de azufre, Gram-positivas, formadoras de esporas, desnitrificantes, anaeróbicas, las solubilizadoras de fosfato, bacterias degradadoras de celulosa, hongos y actinomicetos. Las poblaciones de heterótrofos, solubilizadoras de fosfato, oxidativas de azufre y los hongos estuvieron más representadas en la temporada lluviosa, mientras que, las Gram-negativas y Gram-positivas, nitrificantes, desnitrificantes, descomponedoras de celulosa y los actinomicetos, en la temporada de invierno. El tamaño poblacional de otros microorganismos disminuyó o se mantuvo durante toda la temporada. Los nutrientes del suelo, tales como N, P, K (Kg/ha) y el contenido total de C (%) fueron mayores en la temporada de lluvias, y no siguieron ninguna tendencia común de cambio a través del período de estudio. El pH del suelo y la salinidad (mS/cm) variaron de 6-8 y 6.4-19.5, respectivamente, lo que afectó significativamente la dinámica de la población microbiana. La determinación de la diversidad de bacterias en el suelo del manglar Bhitarkanika por el método de cultivo mostró el predominio de los géneros de bacterias como Bacillus, Pseudomonas, Desulfotomaculum, Desulfovibrio, Desulfomonas, Methylococcus, Vibrio, Micrococcus, Klebsiella y Azotobacter. El análisis de componentes principales (ACP) reveló una correlación entre las variables locales del ambiente y los sitios de muestreo en la comunidad microbiana en el suelo del manglar.

Mechanism of reductive photoactivation of enzymes of C4 pathway.

Light, besides initiating primary photochemical processes, alters the redox state of soluble components in chloroplast. The present review attempts to cover the mechanism of reductive photoactivation of enzymes of photosynthetic carbon reduction cycle using key enzymes as examples. The reduced soluble components — ferredoxin, thioredoxin and NADPH, in turn, cause the reduction of disulphides to dithiols of chloroplastic enzymes. NADP-malate dehydrogenase is subject to activation by light through changes in NADPH/NADP. The key enzyme of C4 photosynthesis-PEP carboxylase, though cytosolic, has been shown to be activated by disulphide/sulphhydryl interconversion by reductants generated in light through chloroplast electron transport flow. Pyruvate Pi dikinase activity is controlled by the adenylate energy charge. It remains unclear how light controls the activation of cytosolic enzymes.