Betaine supplementation improved L-threonine fermentation of Escherichia coli THRD by upregulating zwf (glucose-6-phosphate dehydrogenase) expression

BACKGROUND: The supplementation of betaine, an osmoprotective compatible solute, in the cultivation media has been widely used to protect bacterial cells. To explore the effects of betaine addition on industrial fermentation, Escherichia coli THRD, an L-threonine producer, was used to examine the production of L-threonine with betaine supplementation and the underlying mechanism through which betaine functions was investigated. RESULTS: Betaine supplementation in the medium of E. coli THRD significantly improved L-threonine fermentation parameters. The transcription of zwf and corresponding enzyme activity of glucose-6-phosphate dehydrogenase were significantly promoted by betaine addition, which contributed to an enhanced expression of zwf that provided more nicotinamide adenine dinucleotide phosphate (NADPH) for L-threonine synthesis. In addition, as a result of the betaine addition, the betaine-stimulated expression of enhanced green fluorescent protein (eGFP) under the zwf promoter within a plasmid-based cassette proved to be a transcription-level response of zwf. Finally, the promoter of the phosphoenolpyruvate carboxylase gene ppc in THRD was replaced with that of zwf, while L-threonine fermentation of the new strain was promoted by betaine addition. Conclusions: We reveal a novel mode of betaine that facilitates the microbial production of useful compounds. Betaine supplementation upregulates the expression of zwf and increases the NADPH synthesis, which may be beneficial for the cell growth and thereby promote the production of L-threonine. This finding might be useful for the production of NADPH-dependent amino acids and derivatives in E. coli THRD or other E. coli strains.

Bandagem ajustável do tronco pulmonar: IX: atividade da G6PD do miocárdio de cabras adultas submetido ao treinamento ventricular / Reversible pulmonary trunk banding: IX. G6PD activity of adult goat myocardium submitted to ventricular retraining

OBJETIVO: O aumento da atividade miocárdica da Glicose 6-Fosfato Desidrogenase tem sido demonstrado na insuficiência cardíaca. Este estudo avalia a atividade miocárdica da Glicose 6-Fosfato Desidrogenase no treinamento do ventrículo subpulmonar de cabras adultas. MÉTODOS: Foram utilizadas 18 cabras adultas, divididas em três grupos: convencional (bandagem fixa), sham e intermitente (bandagem ajustável; 12 horas diárias de sobrecarga). A sobrecarga sistólica (70% da pressão sistêmica) foi mantida durante quatro semanas. As avaliações hemodinâmica e ecocardiográfica foram realizadas durante todo o estudo. Depois de cumprido o protocolo, os animais foram mortos para avaliação morfológica e da atividade da Glicose 6-Fosfato Desidrogenase dos ventrículos. RESULTADOS: Apesar de haver sobrecarga sistólica proporcionalmente menor no ventrículo subpulmonar do grupo intermitente (P=0,001), ambos os grupos de estudo apresentaram aumento da massa muscular de magnitude similar. Os grupos intermitente e convencional apresentaram aumento da massa de 55,7% e 36,7% (P<0,05), respectivamente, em comparação ao grupo sham. O conteúdo de água do miocárdio não variou entre os grupos estudados (P=0,27). O ecocardiograma demonstrou maior aumento (37,2%) na espessura do ventrículo subpulmonar do grupo intermitente, em relação aos grupos sham e convencional (P<0,05). Foi observada maior atividade da Glicose 6-Fosfato Desidrogenase na hipertrofia miocárdica do ventrículo subpulmonar do grupo convencional, comparada aos grupos sham e intermitente (P=0,05). CONCLUSÃO: Ambos os grupos de treinamento ventricular desenvolveram hipertrofia ventricular, a despeito do menor tempo de sobrecarga sistólica no grupo intermitente. A maior atividade de Glicose 6-Fosfato Desidrogenase observada no grupo convencional pode refletir um desequilíbrio redox, com maior produção de fosfato de dinucleotídeo de nicotinamida e adenina e glutationa reduzida, um mecanismo importante da fisiopatologia da insuficiência cardíaca.

OBJECTIVE: Increased glucose 6-phosphate dehydrogenase activity has been demonstrated in heart failure. This study sought to assess myocardial glucose 6-phosphate dehydrogenase activity in retraining of the subpulmonary ventricle of adult goats. METHODS: Eighteen adult goats were divided into three groups: traditional (fixed banding), sham, and intermittent (adjustable banding, daily 12-hour systolic overload). Systolic overload (70% of systemic pressure) was maintained during a 4-week period. Right ventricle, pulmonary artery and aortic pressures were measured throughout the study. All animals were submitted to echocardiographic and hemodynamic evaluations throughout the protocol. After the study period, the animals were killed for morphological and glucose 6-phosphate dehydrogenase activity assessment. RESULTS: A 55.7% and 36.7% increase occurred in the intermittent and traditional right ventricle masses, respectively, when compared with the sham group (P<0.05), despite less exposure of intermittent group to systolic overload. No significant changes were observed in myocardial water content in the 3 groups (P=0.27). A 37.2% increase was found in right ventricle wall thickness of intermittent group, compared to sham and traditional groups (P<0.05). Right ventricle glucose 6-phosphate dehydrogenase activity was elevated in the traditional group, when compared to sham and intermittent groups (P=0.05). CONCLUSION: Both study groups have developed similar right ventricle hypertrophy, regardless less systolic overload exposure of intermittent group. Traditional systolic overload for adult subpulmonary ventricle retraining causes upregulation of myocardial glucose 6-phosphate dehydrogenase activity. It may suggest that the undesirable "pathologic systolic overload" is influenced by activation of penthose pathway and cytosolic Nicotinamide adenine dinucleotide phosphate availability. This altered energy substrate metabolism can elevate levels of free radicals by Nicotinamide adenine dinucleotide phosphate oxidase, an important mechanism in the pathophysiology of heart failure.

Deficiencia de glucosa-6-fosfato deshidrogenasa eritrocitaria en Rosario / Erythrocyte glucose-6-phosphate dehydrogenase deficiency in Rosario / Deficiência de glicose-6-fosfato desidrogenase eritrocitária em Rosario

Se estudió la actividad enzimática (AE) de la enzima glucosa-6-fosfato deshidrogenasa eritrocitaria (G6PD) y la movilidad electroforética (ME) en una población de hombres y mujeres de la ciudad de Rosario (provincia de Santa Fe), Argentina y zona de influencia. Para la determinación de AE se utilizó la técnica cinética de Glock y McLean y para la electroforesis de la enzima, la técnica de M.C. Rattazzi y L.C. Bernini en acetato de celulosa. Los valores normales de actividad enzimática (AE) para hombres y mujeres adultos fueron de 8,1 ± 1,4 UI G6PD/g Hb. Se demostró que los valores de AE son independientes de la edad, sexo y concentración de hemoglobina. En todos los grupos etarios estudiados no se observaron diferencias significativas de AE con respecto a los adultos normales a excepción de los neonatos que presentaron un significativo aumento de la misma, lo cual está directamente relacionado con las características fisiológicas de los eritrocitos del recién nacido. Entre los 686 individuos estudiados se detectaron 2 pacientes deficientes de G6PD, lo que dio una prevalencia de 0,3% y el patrón electroforético correspondiente a esta población fue 98% (n: 672) para G6PD B y 2% (n: 14) para G6PD con movilidad rápida tipo A.

Enzymatic activity (EA) of erythrocyte glucose-6-phosphate dehydrogenase (G6PD) and electrophoretic mobility (EM) have been studied in a population of males and females in the city of Rosario and its area of influence. To determine EA, the Glock and McLean kinetic technique was used. Electrophoretic mobility assay was performed by M.C. Rattazzi and L.C. Bernini technique in cellulose acetate gel. Results demonstrated that the EA values in normal individual are independent of age, sex and hemoglobin values. The normal values of EA were: 8.1±1.4 IU of G6PD/g Hb. There were no significant differences in different age groups studied regarding healthy adults, except for neonatal group that yielded a significant EA increase which is directly related to the physiological characteristics of newborn erythrocytes. Two patients out of 686 individuals bearing G6PD deficiency were detected, corresponding to 0.3% prevalence. The electrophorectic mobility pattern was 98% (n: 672) for G6PD B, and 2% (n: 14) for G6PD A fast mobility variant.

Foi estudada a atividade enzimática (AE) da enzima glicose-6-fosfato desidrogenase eritrocitária (G6PD) e a mobilidade eletroforética (ME) numa população de homens e mulheres da cidade de Rosario, província de Santa Fe, Argentina e zona de influência. Para a determinação da AE foi utilizada a técnica cinética de GlocK e Mc Lean e para a eletroforese da enzima a técnica de M.C. Rattazzi e L.C. Bernini em acetato de celulose. Os valores normais de atividade enzimática (AE) para homens e mulheres adultos foram de 8,1 ± 1,4 UI G6PD/g Hb. Foi demonstrado que os valores da AE são independentes da idade, sexo e concentração de hemoglobina. Em nenhum dos grupos etários estudados foram observadas diferenças significativas de AE no que diz respeito aos adultos normais, com exceção dos neonatos que apresentaram um significativo aumento da mesma, o qual está diretamente relacionado com as características fisiológicas dos eritrócitos do recém-nascido. Entre os 686 indivíduos estudados foram detectados 2 pacientes deficientes de G6PD, o que deu uma prevalência de 0,3% e o padrão eletroforético correspondente a esta população foi de 98% (n: 672) para a G6PD B e 2% (n: 14) para G6PD com mobilidade rápida tipo A.

Role of bilirubin as antioxidant in neonatal jaundice and effect of ethanolic extract of sweet lime peel on experimentally induced jaundice in rat.

Bilirubin above a threshold level is toxic to human system and is excreted in urinary and through gastrointestinal tract. The role of bilirubin as antioxidant is debatable. This paper aims at elucidating the role of bilirubin as an antioxidant in neonatal jaundice patients. It is observed that bilirubin up to 6 mg/dl in blood acts as an antioxidant and above 12.5 mg/dl is strongly prooxidant. Phototherapy is the accepted therapeutic management of neonatal jaundice and has been shown to enhance the oxidative stress. Approaches have been taken to formulate a herbal medication which will reduce bilirubin level in the neonates without inducing additional damages. The ethanolic extract of sweet lime peel, administered orally at a dose of 72 microg is found to reduce the oxidative stress in erythrocytes of phenylhydrazine-induced jaundiced rats treated with phototherapy.

Glycolysis in Plasmodium falciparum results in modulation of host enzyme activities.

BACKGROUND & OBJECTIVES: Plasmodium falciparum, the causative agent of the most serious form of malaria, infects about 5-10% of the world human population per year. It is well established that the erythrocytic stages of the malaria parasite rely mainly on glycolysis for their energy supply. In the present study, the glucose utilisation of erythrocyte population with parasitaemia levels similar to that of malaria patients was measured. The results allowed us to assess the effect of the parasites on the glucose utilisation of the vast majority of uninfected erythrocytes. METHODS: Using [2-13C]glucose and nuclear magnetic resonance (NMR) technique, the glucose utilisation in normal red blood cell (RBC) and P. falciparum infected red blood cell (IRBC) populations was measured. The IRBC population consisted of > 96% RBC and < 4% of parasite infected red blood cells (PRBC). The glycolytic enzymes were assayed to assess the effect of infected red cells on the enzymatic activities of uninfected ones. RESULTS: The rate of glucose utilisation by IRBC was considerably higher than that of RBC. Upon addition of 25% v/v conditioned culture medium (CM) of IRBC, RBCs exhibited a significant decrease in glucose utilisation. The CM could directly inhibit the activities of RBC glycolytic enzymes-phosphofructokinase (PFK) and pyruvate kinase (PK), without interfering with the activity of the pentose phosphate pathway enzyme-glucose-6-phosphate dehydrogenase (G-6-PD). INTERPRETATION & CONCLUSION: The present study showed that the clinical level of P. falciparum infected RBCs (< 4% parasitaemia) significantly enhance the glycolytic flux as well as down-regulate the glucose utilisation rate in the majority of uninfected RBC population. The mechanism of inhibition seems to be direct inhibition of the regulatory glycolytic enzymes-PFK and PK.

Physiological changes in certain test plants under automobile exhaust pollution.

Plants are the only living organisms which have to suffer a lot from automobile exhaust pollution because they remain static at their habitat. But such roadside plants like Nerium indicum Mill., Boerhaavia diffusa L., Amaranthus spinosus L., Cephalandra indica Naud., and Tabemaemontana divaricata L. can easily avoid the effects of air pollution by altering their physiological pathways pertaining to photosynthesis and respiration. Stomatal closure in Boerhaavia, Amaranthus, Cephlandra and stomatal clogging in Nerium and Tabemaemontana help these plants in preventing the entry of poisonous gases. The increased activity of the enzyme Phosphoenol Pyruvate Carboxylase (PEPCase) belonging to C4 pathway helps Nerium and Boerhaavia (both C3 plants) in carbon fixation under stress condition. Photorespiration is favoured in Amaranthus, Cephalandra and Tabernaemontana to compensate for the over production of ATP in them. Owing an inefficient gaseous exchange in Boerhaavia and Tabemaemontana, the activity of Glucose 6--Phosphate Dehydrogenase (G6-PD) also increases for the preferential shift to Pentose Phosphate Pathway to produce excess NADPH+H+ which are likely to re-oxidize by metabolic reactions not linked to electron transport chain.

Changes in some liver enzymes in streptozotocin-induced diabetic rats fed sapogenin extract from bitter yam (Dioscorea polygonoides) or commercial diosgenin / Cambios en Algunas Enzimas Hepáticas en ratas con Diabétes Inducida Mediante Estreptozotocina, Alimentadas con Extracto de Sapogenina de ñame Amargo (Dioscorea polygonoides) o Diosgenina Comercial

The effects of steroidal sapogenin extract from bitter yam or commercial diosgenin on liver enzyme changes were investigated Diabetic male Wistar rats were fed diets supplemented with 1 steroidal sapogenin extract or commercial diosgenin for three weeks. Plasma glucose levels and the activities of hepatic glucose-6-phosphatase, pyruvate kinase and glucose-6-phosphate dehydrogenase were assessed Liver total cholesterol, HDL-cholesterol and total phospholipid were also measured. Plasma glucose decreased significantly (p < 0.05) in diabetic rats fed the three test diets compared to the diabetic control. The three test diets significantly decreased glucose-6-phosphatase activity compared to the diabetic control The activities of ATP-citrate lyase, pyruvate kinase and glucose-6-phosphate dehydrogenase were significantly reduced in the liver of diabetic rats compared to normal control. Supplementation of the diet with bitter yam steroidal sapogenin extract or commercial diosgenin did not significantly alter ATP citrate lyase and pyruvate kinase activities but significantly increased glucose-6-phosphate dehydrogenase activity in the liver compared to diabetic rats. This study shows that the feeding of the two test diets to diabetic rats results in alterations in the metabolism of glucose with subsequent reduction in plasma glucose concentration

Se investigaron los efectos del extracto de sapogenina esteroidal del ñame amargo o la diosgenina comercial, sobre los cambios enzimáticos del hígado. A ratas Wistar machos con diabetes les fueron suministradas dietas con suplementos de 1% de extracto de sapogenina esteroidal o diosgenina comercial por espacio de tres semanas. Se evaluaron los niveles de glucosa plasmática y las actividades de la glucosa-6-fosfatasa hepática, el piruvato kinasa y la glucosa-6-fosfato deshidrogenasa. Asimismo fueron medidos el colesterol total del hígado, el colesterol HDL y el fosfolípido total. La glucosa plasmática disminuyó significativamente (p < 0.05) en las ratas diabéticas a las que se les alimentó con las tres dietas de la prueba, en comparación con el control diabético. Las tres dietas de la prueba disminuyeron significativamente la actividad de la glucosa-6-fosfatasa en comparación con el control diabético. Las actividades de la ATP-citrato liasa, la piruvato kinasa y la glucosa-6-fosfato deshidrogenasa disminuyeron significativamente en el hígado de las ratas diabéticas, en comparación con el control normal. El suplemento dietético con extracto de sapogenina esteroidal de ñame amargo o la diosgenina comercial no alteró de manera significativa las actividades de la ATP-citrato liasa y la piruvato kinasa, pero aumentó significativamente la actividad de la glucosa-8-fosfato deshidrogenasa en el hígado, en comparación con las ratas diabéticas. Este estudio demuestra que la alimentación con las dos dietas de prueba suministrada a las ratas diabéticas, produce alteraciones en el metabolismo de la glucosa, con la consiguiente reducción de la concentración de glucosa plasmática

Histochemical localization of enzymes and lipids in the ovary of a vespertilionid bat, Scotophilus heathi, during the reproductive cycle

O presente estudo descreve as mudanças sazonais na D5 3b hidroxiesteróide desidrogenase (3b-HSD), glicose-6 fosfato desidrogenase (G-6-PD), e lipídios no ovário de um morcego vespertilionidae, Scotophilus heathi. As atividades totais dos lipídios e do 3b-HSD estão restritas às células tecais e intersticiais do ovário. Os lipídios, 3b-HSD e G-6-PD totais, aumentaram significantemente durante a recrudescência, e permaneceram elevados durante a dormência de inverno e o período de acasalamento, quando comparados a outras fases reprodutivas. A alta incidência de atividade de lipídios e enzimas nas células intersticiais durante o período de acasalamento e durante o período de ovulação sugere claramente que estas células estão ativamente envolvidas na esteroidogênese. O declínio da atividade dos lipídios e enzimas durante a dormência de inverno, o qual se correlaciona com os níveis decrescentes da esteroidogênese, podem ser o fator responsável pela longa sobrevivência do folículo de De Graaf no ovário do S. heathi.

Incremento de la glucosa-6-fosfato-deshidrogenasa eritrocitaria en jóvenes con sindrome de Down tras un programa de actividad física de 12 semanas / A 12-week physical activity program increases glucose-6-phosphate-dehydrogenase activity in Down syndrome adolescents

Recientemente se ha publicado que las células trisómicas presentan una mayor sensibilidad al daño oxidativo, que podría justificar la frecuente asociación de síndrome de Down a aterosclerosis, envejecimiento precoz, etc. Para conocer el posible papel de la actividad física moderada en la mejora de la capacidad antioxidante se estudió el comportamiento de la enzima glucosa-6-fosfato-deshidrogenasa (G6PDH) eritrocitaria en 31 adolescentes varones (16.3 ± 1.1 años) tras desarrollar un programa de 12 semanas con tres sesiones (45-60 minutos) y una intensidad del 60-75% frecuencia cardíaca máxima teórica. Nuestros resultados indican una mayor actividad de G6PDH en individuos con síndrome de Down cuando se compara con controles sin trisomía ajustados a su sexo, edad e índice de masa corporal. Asimismo observamos un incremento significativo de su actividad tras completar nuestro programa de 12 semanas. Podemos concluir que la actividad física moderada mejora la capacidad antioxidante en jóvenes con síndrome de Down.

In recent years it has been claimed that trisomic cells are more sensitive to oxidative stress since there is an imbalance in the hydrogen peroxide metabolism. We designed the present study to assess the activity level of antioxidant enzyme glucose-6-phosphate-dehydrogenase (G6PDH) of erythrocytes in 31 male adolescents with Down syndrome (mean age 16.3 +/- 1.1) after performing a 12 week aerobic training program. First of all, a significant increase of 14.9% in the catalytic activity of G6PDH was observed in male adolescents with Down syndrome when compared with age, sex and body mass-matched controls without trisomy. After 12-wk program its activity increased significantly compared to baseline value in Down syndrome individuals. Our data are consistent with previous evidence of the existence of higher oxidative stress in adolescents with Down syndrome when compared to the general population. We may also conclude that G6PDH activity was significantly increased after a 12 week exercise program.

Frequency of glucose-6-phosphate dehydrogenase deficiency in some ethnic groups of Pakistan

To determine the frequency of G6PD deficiency in young healthy adult males of some ethnic groups in Pakistan. Design: Descriptive study. Place and Duration of Study: Study performed in Combined Military Hospital, Attock in collaboration with Armed Forces Institute of Pathology, Rawalpindi from October 2003 to January 2004. Patients and Asymptomatic and healthy adult males were included in the study. A brief clinical record including age, ethnic group, place of residence, and history of past illnesses including fever, episodes of recurrent jaundice were recorded. Met-hemoglobin reduction test for G6PD screening was performed. Hemoglobin, red cell indices and total leukocyte count of G6PD deficient cases were measured on Sysmex KX 32 hematology analyzer. Three thousand adult males with age between 17 years to 23 years were screened. G6PD deficiency was detected in 1.8%. Deficiency state was 1.07% in Kashmiris, 1.47% in Punjabis, 2.77% in Sindhis, and 3.17% in Pathans. Past history of recurrent jaundice was present in 5.7%. Mild anemia was present in 3.8%. Frequency of G6PD deficiency was 1.8% in young healthy adults with insignificant difference among various ethnic groups except in Pathans

Effect of amaranth leaves on dimethylhydrazine-induced changes in multicomponent antioxidant system of rat liver.

Effect of prefeeding dehydrated amaranth (A. gangeticus) leaves at 10 and 20% levels on a chemical toxicant, dimethylhydrazine (DMH)-induced free radical stress in rat liver was evaluated. DMH-induced rise in hepatic malondialdehyde (MDA), was diminished by AL. AL intake resulted in a significant increase in hepatic glutathione (GSH). The feeding of AL at 10% level increased the hepatic glucose-6-phosphate dehydrogenase (G-6-PDH) activity, while that at 20% level increased the hepatic glutathione reductase (GSSGR) as well, in addition to G-6-PDH. Amaranth leaves at 10 and 20% levels of feeding diminished the hepatic superoxide dismutase and glutathione peroxidase (GSH-Px) activities. DMH influenced adversely the hepatic antioxidant enzyme activities. Simultaneous administration of DMH and feeding of AL enhanced the DMH-induced decrease in hepatic GSH-Px. DMH enhanced formation of micronuclei was reverted significantly by AL intake. Hence, it was concluded that the consumption of AL at 20% level reduced DMH-induced impaired antioxidant status in rat liver.

Effect of a polyherbal formulation, Ambrex, on butylated hydroxy toluene (BHT) induced toxicity in rats.

Effect of polyherbal formulation Ambrex was evaluated in butylated hydroxytoluene (BHT) induced toxicity of lungs and liver in rats. Toxicity was produced by administering BHT (500 mg/kg/day) for 3 days. Lung damage was evidenced by elevated levels of broncho alveolar lavage fluid (BAL) parameters such as protein, lactate, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), acid phosphatase (ACP) and glucose-6-phosphate dehydrogenase (G6PDH). Liver damage was proved by elevated levels of serum protein and markers such as LDH, ALP, aspartate amino transferase (AST), alanine amino transferase (ALT), decreased level of lipid peroxides (LPO) in serum and glutathione (GSH) in liver. Administration of aqueous suspension of Ambrex (50 mg/kg orally) retained these elevated levels of BAL-protein, lactate, LDH, ALP, ACP, G6PDH and serum-protein, LDH, ALP, AST and ALT at near normal values. Decreased level of liver GSH was retained at near normalcy in Ambrex pretreated BHT-administered animals. There was no change in liver LPO in all the four groups.

Enzymatic and non-enzymatic antioxidants in selected Piper species.

Piper species, commonly used in diet and traditional medicine were assessed for their antioxidant potential. Catalase activity was predominated in Piper longum, followed by Piper cubeba, green pepper, Piper brachystachyum and Piper nigrum. P. nigrum was richest in glutathione peroxidase and glucose-6-phosphate dehydrogenase, green pepper was richest in peroxidase and vitamin C while vitamin E was more in P. longum and P. nigrum. P. brachystachyum and P. longum were rich sources of vitamin A. All the Piper species had GSH content of around 1 to 2 nM/g tissue. The antioxidant components of Piper species constitute a very efficient system in scavenging a wide variety of reactive oxygen species. Antioxidant potential of Piper species was further confirmed by their ability to curtail in vitro lipid peroxidation by around 30-50% with concomitant increase in GSH content.

Pyrethroid susceptibility & enzyme activity in two malaria vectors, Anopheles stephensi (Liston) &. A. culicifacies (Giles) from Mysore, India.

BACKGROUND & OBJECTIVES: Anopheles stephensi and A. culicifacies are the two major vectors of malaria in Karnataka. These mosquito populations are continuously being exposed directly or indirectly to different insecticides including the most effective pyrethroids. Therefore, there is a threat of insecticide resistance development. We subjected these vectors to larval bioassay using two popular pyrethroids viz deltamethrin and permethrin. An attempt was also made to correlate the activities of certain detoxifying enzymes such as A- esterase, B-esterase, glutathione-S transferase (GST) and glucose-6-phosphate dehydrogenase (G6PD) with the tolerance levels of the two vectors. METHODS: Larval bioassay was carried out following the standard WHO procedure on field-collected larvae. The LC50 and LC90 values were calculated following Probit analysis. Biochemical estimations were done with a U V spectrophotometer and the isozyme studies employing native polyacrylamide gel electrophoresis (PAGE). RESULTS: The results of the larval bioassay revealed that A. stephensi has more tolerance to deltamethrin than A. culicifacies and vice versa for permethrin. Biochemical estimations revealed significantly (P < 0.05) higher levels of A-esterase and GST activity in A. stephensi whereas A. culicifacies showed significantly higher (P < 0.05) levels of B-esterase and G6PD activity. The total larval protein assayed was found to be more (P < 0.05) in A. stephensi. The isozyme profiles also revealed difference in mobility, intensity and the number of bands. INTERPRETATION & CONCLUSION: As these malaria vectors are exposed to different kinds of insecticides, they develop increased enzyme activities to overcome the insecticide pressure. This has enhanced the tolerance level against the pyrethroids tested. Thus, A. stephensi was found to be tolerant to deltamethrin depicting a higher activity of A-esterase and GST enzymes, whereas the higher activity of B-esterase and G6PD has resulted in the development of tolerance to permethrin in A. culicifacies.

Acephate induced oxidative damage in erythrocytes.

The effect of oral administration of acephate (360 mg/kg body weight), for 15 days, daily, was investigated on the erythrocytes of male rats. Activities of acetyl cholinesterase and glucose-6-phosphate dehydrogenase decreased, while those of glutathione-s-transferase and glutathione reductase increased. Decreased glutathione content and increased lipid peroxidation suggest that there was increased oxidative stress in the erythrocytes of treated animals. Increased cholesterol/phospholipid ratio in the erythrocyte membranes and morphological changes in RBCs (scanning electron microscopy studies) were observed in acephate treated animals. The results clearly suggest that acephate induced oxidative stress in erythrocytes leads to morphological changes.

Effect of primaquine standard dose (15 mg/day for 14 days) in the treatment of vivax malaria patients in Thailand.

Primaquine (8-aminoquinoline), the only effective drug to prevent relapses of the persistent liver forms of Plasmodium vivax and Plasmodium ovale, can induce hemolytic anemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The severity varies considerably among affected individuals. Three hundred and sixty-four Plasmodium vivax cases (342 G6PD-normal and 22 G6PD-deficient) were given a 3-day course of chloroquine (total dose 1,500 mg) followed by primaquine 15 mg a day for 14 days and completed a 28-day follow-up. All G6PD-deficient patients were male; there were no relapses or serious adverse events during the study. Although a significant decrease in hematocrit levels and an increase in the percent reduction of hematocrit levels were observed on day 7 (34.9+/-5.0 vs 26.7+/-5.4; (-1.2)+/-14.4 vs (-24.5) +/-13.9 respectively) and on day 14 (35.7+/-4.3 vs 30.9+/-3.1; 1.6+/-17.8 vs (-11.0) +/-19.3 respectively) blood transfusion was not required. Daily doses of 15 mg of primaquine for 14 days following a full course of chloroquine when prescribed to Thai G6PD deficient patients where Mahidol variant is predominant, are relatively safe.

Short-term effects of thyroid hormones on lipogenic enzymes and 14C-acetate incorporation into various lipid classes: in vivo and in vitro studies.

Short-term effect of 3,5,3'-triiodothyronine (T3) and 3,5-diiodothyronine (T2) on lipid metabolism in the liver of Anabas testudineus was examined. In vivo injections of both T3 and T2 at a concentration of 10 ng/g body weight increased malic enzyme (ME), glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activity compared to 6-propylthiouracil (6-PTU) treated group. Treatment of 6-PTU results in the accumulation 14C-acetate into fat and thyroid hormones' treatment reduce it. In vitro experiments show that malic enzyme activity is augmented only by high concentration of T3 (10(-7) M) where as all concentrations of T2 increase its activity. In vitro studies with T3 showed a biphasic effect on cholesterol content. Conversely T2 in vitro, reduced cholesterol content with all concentrations. From these results it can be concluded that both T3 and T2 have short-term effect on lipid metabolism in Anabas.

Erythrocyte glucose-6-phosphate dehydrogenase activity assay and affinity for its substrate under "physiological" conditions

Glucose-6-phosphate dehydrogenase (G6PD) activity and the affinity for its substrate glucose-6-phosphate were investigated under conditions similar to the physiological environment in terms of ionic strength (I: 0.188), cation concentration, pH 7.34, and temperature (37oC). A 12.4, 10.4 and 21.4 percent decrease was observed in G6PD B, G6PD A+ and G6PD A- activities, respectively. A Km increase of 95.1, 94.4 and 95.4 percent was observed in G6PD B, G6PD A+ and G6PD A-, respectively, leading to a marked decrease in affinity. In conclusion, the observation of the reduced activity and affinity for its natural substrate reflects the actual pentose pathway rate. It also suggests a much lower NADPH generation, which is crucial mostly in G6PD-deficient individuals, whose NADPH availability is poor

LHRH induced changes in the interrenal gland of the frog Rana cyanophlyctis (Schn.).

Administration (i.m.) of synthetic mammalian LHRH (40 ng/frog, alternate day for 30 days) to adult male intact frogs R. cyanophlyctis resulted in activation of the interrenal cells as shown by increases in nuclear diameters of the interrenal cells, activity (histochemical demonstration) of delta 5-3 beta-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase and concomitant decrease in sudanophilic lipid droplets in the interrenal gland when compared to those of controls. These changes were not observed in the interrenal gland of LHRH treated hypophysectomized frogs. The results indicate that LHRH stimulates secretory activity of the interrenal cells and action may not be directly on the adrenal gland.

Glicose-6-fosfato desidrogenase e 6-fosfogliconato desidrogenase: atividade e cinética em condiçöes fisiológicas / Glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase: activity and kinetic in physiological conditions

Foram determinadas as atividades enzimaticas da G-6-PDG aos seus substratos G-6-P e 6-PGA respectivamente, em sistemas reagentes recomendados pela OMS e em condiçöes próximas às fisiológicas intraeritrocitárias de pH, temperatura, força iônica, e concentraçäo de moduladores, de indivíduos normais portadores das variantes G-6-PDB e G-6-PDA + e indivíduos deficientes de G-6-PD variante G-6-PDA -, para se estabelecer comparaçöes