Manganese influx and its utilization efficiency in wheat.

Manganese deficiency in wheat has become an important nutritional disorder particularly in alkaline calcareous soils where rice-wheat rotation is followed. This experiment was aimed to study the mechanism of Mn efficiency during various developmental stages in six wheat cultivars grown at two Mn levels viz. 0 and 50 mg Mn kg-1soil (Mnapplied as MnSO4.H20) in pots. The Mn vegetative efficiency calculated on the basis of shoot dry weight at anthesis indicated HD 2967 and PBW 550 (bread wheat) as Mn efficient and durums as Mn inefficient. The efficient cultivars recorded highest values for influx, uptake, shoot dry weight, leaf area/plant, SPAD index, Fv/Fmratio and root length that explained their higher efficiencies whereas inefficiency of durum cultivars was attributed to their smaller roots and lower influx. Under Mn deficiency, PDW 314 and PDW 291 retained 68% and 64%, respectively, of total Mn uptake in vegetative parts (stem and leaves) and lowest in grains 7% and 5%, respectively, whereas PBW 550, BW 9178 and HD 2967 retained 29, 37 and 34% in vegetative parts, and 21, 17 and 15 % in grains, respectively at maturity. Higher utilization efficiency of efficient genotypes also indicated that increased Mn uptake with Mn supply produced more efficiently grains in efficient genotypes but vegetative parts in inefficient genotypes. Hence Mn efficiency of a cultivar could be explained by longer roots, higher uptake, influx and efficiency index during vegetative phase and higher grain yield and utilization efficiency during generative phase.

Avaliação da exposição ambiental ao manganês na população residenteno entorno de um estaleiro no município de Angra dos Reis, RJ / Assessment of environmental exposure to manganese in the resident population in the vicinity of a site in the municipality of Angra dos Reis, RJ

O manganês é um componente essencial no processo de soldagem, porconferir dureza e resistência, assim como na produção do aço, onde é usadocomo agente dessulfurante e redutor. Apesar de ser um elemento essencial ao homem, atuando na formação dos ossos e tecidos, função reprodutiva e metabolismo de carboidratos e lipídios, a exposição crônica ao Mn afeta, principalmente, o sistema nervoso central. Uma vez que solda e aço são essenciais para a construção e reparo de navios, essa indústria torna-se uma importante fonte de exposição ao referido metal. O objetivo deste trabalho foi avaliar a exposição ao manganês na população residente no entorno de um estaleiro em Angra dos Reis-RJ, que foi comparada a um grupo de moradores do município da Serra-ES. A coleta de dados foi realizada através da aplicação de um questionário padronizado fundamentado para o conhecimento das variáveis sócio-econômicas e fatores de risco para a exposição ao metal, resultando em universo amostral de 98 sujeitos e amostras de ar do local exposto. A técnica analítica utilizada para a determinação do manganês nosfluidos biológicos e nos filtros de ar foi a espectrometria de absorção atômica eletrotérmica. (...)

Batch and fixed-bed column biosorption of manganese ion by sargassum filipendula

This paper presents experimental data of the biosorption of manganese onto Sargassum filipendula in both batch and fixed-bed column systems. Batch equilibrium data were used for nonlinear fittings of the Langmuir and Freundlich isotherms. A mathematical model based on mass balances in the fluid and in the sorbent was applied to represent the experimental fixed-bed column data. The utilization of isotherm parameters from the batch experiments in the breakthrough model implied a significant mismatch in relation to the laboratory data. Alternatively, additional fixed-bed column data provided new parameters for the isotherm evaluation, and the corresponding simulated profile of the breakthrough curve reached better agreement to the experimental results.

Encefalopatía hepática en el 2011 / Hepatic encephalopaty in 2011

Hepatic encephalopathy (HE) is a neuropsychiatric and motor disorder, resulting from hepatic failure. It is one of the main manifestations of chronic liver disease and the cardinal presentation of acute liver failure. Its presence and severity are the main prognostic determinants among these patients. It is frequent in advanced chronic liver disease (30-45 percent) and in patients with TIPS (transjugular intrahepatic portosystemic shunt) (10-50 percent). Its pathogenesis is complex and it has multiple components, including ammonia, inflammatory cytokines, benzodiazepine- and manganese-like components, which alter the function of the neuronal cell. Its management requires identification and treatment of the precipitating factors, and ruling out other causes of mental status alteration. The majority of the therapies are aimed at reducing ammonia load in the intestine, such as non absorbable disaccharides (lactulose), antibiotics (neomycin, metronidazole and currently, rifaximin) and other, whose role has yet to be established. Severe encephalopathy is considered an indicator for liver transplantation. This article will analyze mainly hepatic encephalopathy in cirrhotic patients, its classification, etiopathogeny and current management.

La encefalopatía hepática (EH) es un síndrome neuropsiquiátrico y motor, que resulta de una disfunción hepática. Es una de las manifestaciones principales de la enfermedad hepática crónica y la presentación cardinal en la falla hepática aguda. Su presencia y gravedad son uno de los mayores determinantes pronósticos en estos pacientes. Es frecuente en enfermedad hepática crónica avanzada (30-45 por ciento)y en portadores de shunt postosistémico transyugular intrahepático (TIPS) (10-50 por ciento). Su patogénesis es compleja y tiene múltiples componentes, incluyendo el amonio, citoquinas inflamatorias, compuestos que semejan a benzodiacepinas y manganeso, que causan alteración funcional de la célula neuronal. El manejo requiere identificar y tratar los factores precipitantes, además de excluir otras causas de alteración del estado mental. La mayoría de las terapias están dirigidas a reducir la carga de amonio en el intestino, tales como los disacáridos no absorbibles (lactulosa), antibióticos (neomicina, metronidazol y actualmente rifaximina) y otros cuyo rol está por establecerse. La encefalopatía grave es considerada un indicador para trasplante hepático. En este artículo analizaremos principalmente la encefalopatía hepática en pacientes con cirrosis, su clasificación, etiopatogenia y manejo actual.

Role of trace elements in hepatic encephalopathy: zinc and manganese.

Apart from increased blood ammonia, alterations in various other substances have been implicated in the pathogenesis of hepatic encephalopathy (HE). The role of trace elements like zinc and manganese has been described recently. Zinc is an essential trace element and functions as an antioxidant. Low zinc concentrations have been reported in patients with cirrhosis of the liver, particularly those with HE. Patients with fulminant hepatic failure and subacute hepatic failure have also been shown to have low serum zinc levels. In animal experiments, zinc supplementation leads to a reduction in blood ammonia. Zinc deficiency also leads to alteration of neurotransmitters like gamma aminobutyric acid and norepinephrine. Zinc supplementation has been tried in HE. It may have a role in mild chronic HE, though further trials are necessary. Increased serum manganese levels have been shown in acute and chronic hepatitis, cirrhosis and congenital disorders like Alagille's syndrome. High manganese content has been reported in the globus pallidus in animals as well as brain tissues of patients dying of HE. Miners with chronic manganese exposure have encephalopathy and extra-pyramidal features similar to HE. It has been postulated that manganese impairs neuronal oxidative metabolism. The role of manganese in the pathogenesis of HE and the possibility of its chelation as treatment need further study.

Newer aspects of hepatic encephalopathy.

Recently attempts have been made to standardize terminology in the field of hepatic encephalopathy. We are now facing a new problem. Chronic hepatitis C-induced cirrhosis occurs in an older population; this may change the presentation pattern of hepatic encephalopathy in future. Ammonia has once again become prominent as the leading toxin likely to play a role in the pathogenesis of this syndrome. How ammonia interacts with other proposed mechanisms should be an area of active research. The treatment arena has seen some advances. Unfortunately, the economics of having newer treatments approved in the USA is formidable. Rifaximine, L-ornithine-L-aspartate, sodium benzoate and possibly flumazenil appear to be significant advances. More elective shunt suppression for selected patients will be seen. Liver transplantation remains the only option for truly intractable hepatic encephalopathy.

In vitro lethal efficacy of leaf extract of Cannabis sativa Linn on the larvae of Chironomous samoensis Edward: an insect of public health concern.

Leaf extract of C. sativa causes paralysis leading to death in larvae of C. samoensis. The extract brought a drastic change in the morphology of sensilla trichoidea and the general body cuticle. The larvae exposed to the leaf extract also showed a significant reduction in the concentration of Mg and Fe, while Mn showed only slight average increase. Since the sensilla trichoidea has nerve connection, it is expected that the toxic principle of the leaf extract has affected the central nervous system. The significant reduction of the level of Fe indicates that the extract could cause the reduction in oxygen binding capacity of the haemolymph, thereby acting as a respiratory poison in addition to its known role as a neurotoxic substance.

Characterization of high temperature induced stress impairments in thylakoids of rice seedlings.

Exposure of isolated thylakoids or intact plants to elevated temperature is known to inhibit photosynthesis at multiple sites. We have investigated the effect of elevated temperature (40 degrees C) for 24 hr in dark on rice seedlings to characterize the extent of damage by in vivo heat stress on photofunctions of photosystem II (PSII). Chl a fluorescence transient analysis in the intact rice leaves indicated a loss in PSII photochemistry (Fv) and an associated loss in the number of functional PSII units. Thylakoids isolated from rice seedlings exposed to mild heat stress exhibited >50% reduction in PSII catalyzed oxygen evolution activity compared to the corresponding control thylakoids. The ability of thylakoid membranes from heat exposed seedlings to photooxidize artificial PSII electron donor, DPC, subsequent to washing the thylakoids with alkaline Tris or NH2OH was also reduced by approximately 40% compared to control Tris or NH2OH washed thylakoids. This clearly indicated that besides the disruption of oxygen evolving complex (OEC) by 40 degrees C heat exposure for 24 hr, the PSII reaction centers were impaired by in vivo heat stress. The analysis of Mn and manganese stabilizing protein (MSP) contents showed no breakdown of 33 kDa extrinsic MSP and only a marginal loss in Mn. Thus, we suggest that the extent of heat induced loss of OEC must be due to disorganization of the OEC complex by in vivo heat stress. Studies with inhibitors like DCMU and atrazine clearly indicated that in vivo heat stress altered the acceptor side significantly. [14C] Atrazine binding studies clearly demonstrated that there is a significant alteration in the QB binding site on D1 as well as altered QA to QB equilibrium. Thus, our results show that the loss in PSII photochemistry by in vivo heat exposure not only alters the donor side but significantly alters the acceptor side of PSII.

Efeitos da suplementação dietética com quelatos de zinco e de manganês na produção, qualidade de ovos e morfologia intestinal de galinhas poedeiras / Effects of chelated and inorganic zinc and manganese supplementation on egg production, egg quality and intestinal morphology for laying hens

Um experimento foi conduzido para estudar o efeito de fontes quelatadas de zinco e manganês em comparação à suplementação com óxido de zinco e sulfato de manganês em dietas para poedeiras. Uma dieta controle à base de milho-soja (17 porcento PB, 3,80 porcento Ca, 0,36 Pd, 50 mg Zn, 70 mg Mn) foi suplementada com 0 ou 40 ppm de Zn adicional, provindo do óxido de Zn ou quelato de Zn, e 0 ou 40 ppm de Mn adicional, provindo do sulfato de Mn ou quelato de Mn, em um arranjo fatorial de tratamentos 3x3. A unidade experimental foi representada por 8 aves alojadas em 4 gaiolas adjacentes. O experimento obedeceu um delineamento tipo blocos ao acaso, com 9 tratamentos e 8 repetições. Um total de 640 galinhas...

Monitoreo biológico en trabajadores expuestos al manganeso / Biological monitoring among workers exposed to manganese

El manganeso es un elemento abundante en el ambiente. Su presentación como dióxido de Mn es la más importante en el comercio y responsable de intoxicaciones crónicas. Su uso más frecuente es en la industria sidermetalúrgica y como funguicida. En el presente trabajo se analiza su metabolismo, el cuadro clínico de la intoxicación aguda y crónica, el diagnóstico diferencial y el tratamiento. Luego de consideraciones sobre el monitoreo ambiental y el monitoreo biológico, se describe un estudio realizado sobre una población de 200 trabajadores de una industria siderometalúrgica de ferroaleaciones, investigados clínicamente y a través del monitoreo biológico con dosaje de manganeso sanguíneo. Se completa el trabajo con consideraciones sobre la determinación de la aptitud laboral en los trabajadores expuestos al manganeso en su ambiente de trabajo

Role of Ca2+ influx in the tert-butyl hydroperoxide-induced apoptosis of HepG2 human hepatoblastoma cellse

Oxidative stress appears to be implicated in the pathogenesis of various diseases including alcoholic liver injury. In this study we investigated the mechanism of apoptosis induced by tert-butyl hydroperoxide (TBHP) in HepG2 human hepatoblastoma cells. Treatment with TBHP significantly reduced glutathione content and glutathione reductase activity, and increased glutathione peroxidase activity, indicating that TBHP induced oxidative stress in the HepG2 cells. TBHP also induced reduction of cell viability and DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. In addition, TBHP induced a sustained increase in intracellular Ca2+ concentration, which was completely prevented by the extracellular Ca2+ chelation with EGTA. TBHP also induced Mn2+ influx. These results indicate that the intracellular Ca2+ increase by TBHP is exclusively due to Ca2+ influx from the extracellular site. Treatment with either an extracellular (EGTA) or an intracellular Ca2+ chelator (BAPTA/AM) significantly suppressed the TBHP-induced apoptosis. Taken together, these results suggest that TBHP induced the apoptotic cell death in the HepG2 cells and that Ca2+ influx may play an important role in the apoptosis induced by TBHP.

Kinetic properties of poly (2'-0-methycytidylic acid)- directed reverse transcriptase reaction

Poly (2'-O-methylcytidylic acid) is recognized as a template in reactions catalyzed by RNA-dependent DNA polymerases in the presence of Mn2+ as divalent cation. We report that kinetic data obtained for dGTP and template under optimal experimental conditions in the reaction catalyzed by reverse transcriptase showed some similarities between the poly (2'-O-methylcytidylic acid)Mn2+ and polyribocytidylic acid/Mg2+ systems. The reaction was inhibited by the action of N-ethylmaleimide and novobiocin, and to a lesser extent by ethidium bromide and tetramethyl ethidium bromide

Influencia de algunos iones en la esporulación y formación de delta-endotoxina en cultivos de Bacillus thuringiensis / Influence of several ions on growth in sporulation and delta-endotoxin formation Bacillus thurigiensis

El estudio del efecto de algunos iones en medios de cultivo para Bacillus thuringiensis en los que se emplean fuentes nitrogenadas complejas, revela la necesidad de suplementación de estos medios con sales de Ca+**2, Mg+**2 y Mn+**2 en concentraciones adecuadas, puesto que el aporte de dichos iones por la fuente nitrogenada compleja, resulta insuficiente para lograr óptimos rendimientos en delta endotoxina. La constancia de la relación proteína/UFC pone en evidencia que la ausencia de uno o más iones afecta por igual el fenómeno de esporulación y formación del cristal proteico. En medios deficitarios en Mn+**2 se observa una sensible disminución de las UFC, manifestándose la importancia de dicho ión en el mecanismo de esporulación. La ausencia de Ca+**2 si bien no cumple una función esencial en la formación del cristal, tiene implicancia a nivel industrial, en el manejo de las pastas esporo-cristal