Functional identification and subcellular localization of NAD kinase in the protozoan parasite Giardia intestinalis / Identificación funcional y localización subcelular de la NAD quinasa en el parásito protozoario Giardia intestinalis / Identificação funcional e localização subcelular da NAD quinase no parasita protozoário Giardia intestinalis

Abstract Nicotinamide adenine dinucleotide phosphate (NADP) is an essential biomolecule that participates in the redox homeostasis and synthesis of signaling compounds. NAD kinase (NADK) (EC 2.7.1.23 / 2.7.1.86) is the only enzyme capable of synthesizing NADP. This study offers an approach to the NADP metabolism in the parasite Giardia intestinalis, the etiological agent of giardiasis, a disease of high prevalence in America, Asia and Africa. Through bioinformatics tools a NADK enzyme candidate was identified, whose tertiary structure modeling demonstrated distinctive and universal motifs of characterized NADKs. The corresponding recombinant protein (His-GINADK) was expressed in Escherichia coli BL21 (DE3) and its partial purification was achieved by nickel affinity chromatography. Functional identification, which showed NADP synthesis, was completed through enzymatic assays evaluated by RP-HPLC. A cytosolic localization of the endogenous GINADK enzyme was observed in trophozoites throughout indirect immunofluorescence analysis, using polyclonal antibodies produced in mice by its immunization with the His-GINADK protein, purified from inclusion bodies. Taken together, our results contribute to the understanding of the NADP metabolism and the physiological role of NADK in the Giardia model.

Resumen El dinucleótido de adenina y nicotinamida fosfato (NADP) es una biomolécula esencial que participa en la homeostasis redox y en la síntesis de compuestos de señalización. La única enzima capaz de sintetizar NADP es la NAD Quinasa (NADK, EC 2.7.1.23 / 2.7.1.86). En este estudio se presenta un acercamiento al metabolismo del NADP en el parásito Giardia intestinalis, agente etiológico de la giardiasis, una enfermedad de alta prevalencia en América, África y Asia. Mediante herramientas bioinformáticas se identificó un candidato a NADK, cuya predicción a nivel de estructura terciaria mostró motivos característicos y universales de NADKs previamente caracterizadas. La proteína recombinante correspondiente (His-GINADK) se expresó en Escherichia coli BL21 (DE3) y se purificó parcialmente mediante cromatografía de afinidad a níquel. La síntesis de NADP por parte de la proteína His-GINADK se comprobó mediante ensayos enzimáticos evaluados por RP-HPLC. Adicionalmente, se determinó una localización subcelular citosólica en trofozoítos del parásito, empleando inmunofluorescencia indirecta y anticuerpos policlonales producidos en modelos murinos inmunizados con la proteína His-GINADK purificada a partir de cuerpos de inclusión. Los resultados obtenidos representan un avance en el entendimiento del metabolismo del NADP y de la importancia fisiológica de la NADK en el modelo de Giardia.

Resumo A nicotinamida adenina dinucleótido fosfato (NADP) é uma biomolécula essencial que participa na homeostase redox e na síntese de importantes compostos de sinalização. A NAD quinase (NADK) (EC 2.7.1.23 / 2.7.1.86) é a única enzima capaz de sintetizar o NADP. Este estudo apresenta uma abordagem do metabolismo do NADP no parasita Giardia intestinalis que causa giardíase, uma doença de alta prevalência na América, Ásia e África. Através de ferramentas de bioinformática, um candidato a enzima NADK foi identificado no parasita, cuja modelagem de estrutura terciária, demonstra motivos distintos e universais de NADKs caracterizadas. A correspondente proteína recombinante (His-GINADK) foi expressa em Escherichia coli BL21 (DE3) e a sua purificação parcial foi conseguida por cromatografia de afinidade com níquel. A identificação funcional, que mostrou a síntese de NADP, foi completada através de ensaios enzimáticos avaliados por RP-HPLC. Uma localização citosólica da enzima GINADK endógena foi observada em trofozoítos ao longo da análise de imunofluorescência indireta, utilizando anticorpos policlonais produzidos em camundongos, imunizados com a proteína His-GINADK purificada de corpos de inclusão. Em conjunto, nossos resultados contribuem para a compreensão do metabolismo do NADP e da importância fisiológica do NADK no modelo de Giardia.

Exogenous niacin treatment increases NADPH oxidase in kiwifruit / O tratamento com niacina exógena NADPH oxidase em kiwis

Abstract Kiwifruit are a popular fruit worldwide; however, plant growth is threatened by abiotic stresses such as drought and high temperatures. Niacin treatment in plants has been shown to increase NADPH levels, thus enhancing abiotic stresses tolerance. Here, we evaluate the effect of niacin solution spray treatment on NADPH levels in the kiwifruit cultivars Hayward and Xuxiang. We found that spray treatment with niacin solution promoted NADPH and NADP+ levels and decreased both O2·- production and H2O2 contents in leaves during a short period. In fruit, NADPH contents increased during early development, but decreased later. However, no effect on NADP+ levels has been observed throughout fruit development. In summary, this report suggests that niacin may be used to increase NADPH oxidases, thus increasing stress-tolerance in kiwifruit during encounter of short-term stressful conditions.

Resumo Kiwis são uma fruta popular em todo o mundo; No entanto, o crescimento das plantas é ameaçado por estresses abióticos como a seca e as altas temperaturas. O tratamento com niacina em plantas mostrou aumentar os níveis de NADPH, aumentando assim a tolerância a stress abiótico. Aqui, avaliamos o efeito do tratamento com spray de solução de niacina sobre os níveis de NADPH nos cultivares de kiwis Hayward e Xuxiang. Descobrimos que o tratamento por spray com solução de niacina promoveu níveis de NADPH e NADP + e diminuiu a produção de O2·- e os teores de H2O2 nas folhas durante um curto período. Nos frutos, os teores de NADPH aumentaram durante o desenvolvimento precoce, mas diminuíram mais tarde. No entanto, não se observou qualquer efeito nos níveis de NADP + ao longo do desenvolvimento do fruto. Em resumo, este relatório sugere que a niacina pode ser utilizada para aumentar NADPH oxidases, aumentando assim a tolerância ao estresse em kiwis durante o encontro de condições estressantes de curto prazo.

Molecular and functional characterization of ferredoxin NADP(H) oxidoreductase from Gracilaria chilensis and its complex with ferredoxin

BACKGROUND: Ferredoxin NADP(H) oxidoreductases (EC 1.18.1.2) (FNR) are flavoenzymes present in photosynthetic organisms; they are relevant for the production of reduced donors to redox reactions, i.e. in photosynthesis, the reduction of NADP+ to NADPH using the electrons provided by Ferredoxin (Fd), a small FeS soluble protein acceptor of electrons from PSI in chloroplasts. In rhodophyta no information about this system has been reported, this work is a contribution to the molecular and functional characterization of FNR from Gracilaria chilensis, also providing a structural analysis of the complex FNR/Fd. METHODS: The biochemical and kinetic characterization of FNR was performed from the enzyme purified from phycobilisomes enriched fractions. The sequence of the gene that codifies for the enzyme, was obtained using primers designed by comparison with sequences of Synechocystis and EST from Gracilaria. 5'RACE was used to confirm the absence of a CpcD domain in FNRPBS of Gracilaria chilensis. A three dimensional model for FNR and Fd, was built by comparative modeling and a model for the complex FNR: Fd by docking. RESULTS: The kinetic analysis shows KMNADPH of 12.5 M and a kcat of 86 s-1, data consistent with the parameters determined for the enzyme purified from a soluble extract. The sequence for FNR was obtained and translated to a protein of 33646 Da. A FAD and a NADP+ binding domain were clearly identified by sequence analysis as well as a chloroplast signal sequence. Phycobilisome binding domain, present in some cyanobacteria was absent. Transcriptome analysis of Gch revealed the presence of two Fd; FdL and FdS, sharing the motif CX5CX2CX29X. The analysis indicated that the most probable partner for FNR is FdS. CONCLUSION: The interaction model produced, was consistent with functional properties reported for FNR in plants leaves, and opens the possibilities for research in other rhodophyta of commercial interest.

Exogenous niacin treatment increases NADPH oxidase in kiwifruit

Abstract Kiwifruit are a popular fruit worldwide; however, plant growth is threatened by abiotic stresses such as drought and high temperatures. Niacin treatment in plants has been shown to increase NADPH levels, thus enhancing abiotic stresses tolerance. Here, we evaluate the effect of niacin solution spray treatment on NADPH levels in the kiwifruit cultivars Hayward and Xuxiang. We found that spray treatment with niacin solution promoted NADPH and NADP+ levels and decreased both O2·- production and H2O2 contents in leaves during a short period. In fruit, NADPH contents increased during early development, but decreased later. However, no effect on NADP+ levels has been observed throughout fruit development. In summary, this report suggests that niacin may be used to increase NADPH oxidases, thus increasing stress-tolerance in kiwifruit during encounter of short-term stressful conditions.

Resumo Kiwis são uma fruta popular em todo o mundo; No entanto, o crescimento das plantas é ameaçado por estresses abióticos como a seca e as altas temperaturas. O tratamento com niacina em plantas mostrou aumentar os níveis de NADPH, aumentando assim a tolerância a stress abiótico. Aqui, avaliamos o efeito do tratamento com spray de solução de niacina sobre os níveis de NADPH nos cultivares de kiwis Hayward e Xuxiang. Descobrimos que o tratamento por spray com solução de niacina promoveu níveis de NADPH e NADP + e diminuiu a produção de O2·- e os teores de H2O2 nas folhas durante um curto período. Nos frutos, os teores de NADPH aumentaram durante o desenvolvimento precoce, mas diminuíram mais tarde. No entanto, não se observou qualquer efeito nos níveis de NADP + ao longo do desenvolvimento do fruto. Em resumo, este relatório sugere que a niacina pode ser utilizada para aumentar NADPH oxidases, aumentando assim a tolerância ao estresse em kiwis durante o encontro de condições estressantes de curto prazo.

Biological effect of down-regulating of MTRR gene on cisplatin-resistant ovarian cancer SKOV3 cells in vitro and in vivo studies / 中华妇产科杂志

Objective To study the biological effects of down-regulatingof methionine synthase reductase (MTRR) gene on cisplatin resistant ovarian cancer SKOV3/DDP cell in vitro and in vivo. Methods (1) Establishing the cell line of MTRR down-regulated. Four short hairpin RNA (shRNA) for MTRR gene (U6-GFP-Neo-homo-1106, U6-GFP-Neo-homo-1931, U6-GFP-Neo-homo-419, U6-GFP-Neo-homo-1460) were designed respectively. Western blot was used to detect the interference efficiency and selected the most efficient shRNA. The MTRR 1106 was selected as the best silencing effect of interference fragment and then therecombinant plasmid vector pSicoR-1106 was constructed and transfected into SKOV3/DDP cells.The stably transfected cells was obtained by screening of flow cytometry(FCM).Fluorescence quantitative reverse transcription (RT)-PCR and western blot were used to detect the expression of MTRR mRNA and protein. (2) Study in vitro: recombinant plasmid expression vector pSicoR-1106, pSicoR-NC and packaging plasmid were respectively transfected into 293T cell. SKOV3/DDP cells were transfected by viral supernatant. The experiment was divided into three groups, namely SKOV3/DDP-MTRRi (down-regulated MTRR group), SKOV3/DDP-NC (negative control group), and the SKOV3/DDP (blank control group). The cell growth curves and half maximal inhibitory concentration (IC50) of cisplatin were made by methyl thiazolyl tetrazolium (MTT) method. Three groups cells were treated with different concentration of cisplatin (0, 1, 2 and 4 μg/ml). The clonogenicity efficiency was observed by clony formation test. The cell cycles were measured by FCM . (3) Study in vivo: three groups cells were subcutaneously inoculated into the nude mice to develop a tumor model. Mice were injected intraperitoneally with cisplatin at 2.5 mg/kg (once every 2 days, in 21 rounds), then the tumor growth was observed. The expression of MTRR and proliferation-related Ki-67 antigen by immunohistochemistry in xenograft tumors were measured. Results (1) Results showed that U6-GFP-Neo-homo-1106 was the best shRNA with interference effect to MTRR. The recombinant plasmid pSicoR-1106 was constructed and transfected into SKOV3/DDP. The MTRR mRNA and protein were down-regulated after transfected. This result showed that MTRR down-regulated SKOV3/DDP cell line was constructed successfully. (2) The cell growth curves showed that the growth of SKOV3/DDP-MTRRi cells were significantly decreased compared with that in the SKOV3/DDP-NC cells and SKOV3/DDP cells (P<0.05). The IC50 of SKOV3/DDP-MTRRi, SKOV3/DDP-NC and SKOV3/DDP were 4.01, 7.90, and 8.91 μg/ml, respectively. The IC50 of SKOV3/DDP-MTRRi was significantly lower than that in control cell groups (P<0.05).Clony formation tests showed that the clony numbers of varied concentration of cisplatin of SKOV3/DDP-MTRRi were significantly less than those of SKOV3/DDP-NC cells and SKOV3/DDP cells (P<0.05). FCM showed that when the cisplatin concentration rose to 4 μg/ml, the G0/G1 phase cell ratio in SKOV3/DDP-MTRRi cells group was (72.8±5.0)%, which was significantly higher than those in the SKOV3/DDP-NC cells group and SKOV3/DDP cells group [(64.4±2.5)%and (64.3±3.0)%], respectively (all P<0.05).(3) Six weeks after nude mice intraperitoneal injection with cisplatin, the tumor volume of SKOV3/DDP-MTRRi, SKOV3/DDP-NC and SKOV3/DDP were respectively (97 ± 32), (168 ± 45), and (173 ± 32) mm3, the tumor weight were (0.36±0.17), (1.08±0.17), and (1.11±0.20) g, in which tumor volume and weight of SKOV3/DDP-MTRRi were significantly less than those of SKOV3/DDP-NC cells and SKOV3/DDP cells (all P<0.05). In three groups tumor tissue, positive rates of MTRR were respectively 2/8, 5/8, and 7/8, the positive rates of Ki-67 were respectively1/8, 6/8, and 7/8, in which SKOV3/DDP-MTRRi was significantly lower those SKOV3/DDP-NC cells and SKOV3/DDP cells (all P<0.05). Conclusion The growth and cisplatin resistance of ovarian cancer cells could be decreased by down-expressing of MTRR gene in vitro and in vivo.

Effect of MTRR gene on apoptosis and autophagy pathways in multi-resistant epithelial ovarian cancer / 中华妇产科杂志

Objective To explore the effect of down-regulated methionine synthase reductase (MTRR) gene on the apoptosis and autophagy pathway, and offer a possible approach for the MTRR to reverse the multi-resistant ovarian cancer. Methods (1) The experiment was divided into 3 groups, SKOV3/DDP-MTRRi (down-regulated MTRR group), SKOV3/DDP-NC (negative control group), and SKOV3/DDP (blank control group). Different concentration of cisplatin (0, 1, 2, and 4 μg/ml) treated on 3 groups cells. The apoptosis rate was measured by flow cytometry (FCM). Autophagy was detected by immunofluorescence. Autophagy microtubule associated protein light chain 3β(LC3B) and p62 were detected by western blot. The formation of autophagosome of cells was observed by transmission electron microscope. (2) Detection of autophagy and apoptosis of SKOV3/DDP-MTRRi induced by rapamycin. The experiment was divided into 4 groups included rapamycin group (5 nmol/L rapamycin), rapamycin+cisplatin group (5 nmol/L rapamycin+4μg/ml cisplatin), cisplatin group (4μg/ml cisplatin) and blank control group. LC3B and p62 protein were detected by western blot. The survival rate cells were detected by methyl thiazolyl tetrazolium (MTT) method. The apoptosis rate was measured by FCM. (3) The 3 groups cells (SKOV3/DDP, SKOV3/DDP-NC and SKOV3/DDP-MTRRi) induced by a certain concentration of cisplatin (4 μg/ml) after 48 hours, then detecting the protein expression of caspase, Bcl-2 family in apoptosis pathway and the key proteins in phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) autophagy pathways by western blot, getting the time when the proteins′expression changed. Results (1) The 3 groups cells (SKOV3/DDP, SKOV3/DDP-NC, and SKOV3/DDP-MTRRi) induced by a certain concentration of cisplatin (4 μg/ml) after 48 hours, apoptosis and autophagy of 3 groups of cells were gradually increased with the increased concentration of cisplatin. The apoptosis rate of SKOV3/DDP-MTRRi cells [(26.2 ± 1.4)%] were significantly increased compared with the SKOV3/DDP-NC cells or SKOV3/DDP cells [(14.8 ± 2.4)%, (14.2 ± 2.4)%;all P0.05), but cleaved caspase-3, cleaved caspase-7, cleaved caspase-9, and cleaved PARP were significantly increased in SKOV3/DDP-MTRRi cells (P<0.05). For the autophagy pathway, the expression of phosphorylated Akt (p-Akt) and phosphorylated mammalian target of rapamycin (p-mTOR) were significantly increased (P<0.05), but Akt and mTOR had no significant variation. The expression of phosphatase and tensin homologue deleted on chromosome ten (PTEN) was significantly decreased (P<0.05). Conclusions MTRR silencing significantly increase cisplatin-induced apoptosis and reduce the autophagy induced by cisplatin in SKOV3/DDP cells. Down-regulation of MTRR enhanced the chemosensitivity of cisplatin-resistant ovarian cancer cells may be by activating caspase and Bcl-2 apoptosis family and inhibiting the PI3K/Akt autophagy pathway.

Association of methionine synthase reductase gene polymorphism with unexplained recurrent spontaneous abortion / 中华妇产科杂志

Objective To explore the relationship between the polymorphism of methionine synthase reductase(MTRR) A66G and the susceptibility to unexplained repeated spontaneous abortion (URSA).Methods Total of 200 Henan Han couples with URSA (URSA group) and 76 Henan Han healthy couples without URSA (control group)were enrolled in this study.Their MTRR A66G genotypes were determined by PCR restriction fragment length polymorphism (PCR-RFLP).Results (1) The allele frequencies of MTRR A66G:the frequencies of allele A and allele G in URSA group were 76.5％ (153/200)in husband and 72.8％ (146/200) in wife,23.5％ (47/200) in husband and 27.2％ (54/200) in wife,respectively.The frequencies of allele A and allele G in control group were 78.9％ (60/76) in husband and 78.3％ (59/76) in wife,21.1％ (16/76) in husband and 21.7％ (16/76) in wife,respectively.The frequencies of allele A and allele G were not significantly different between female and male subjects within the same experimental group (P ＞ 0.05),and also there were not significantly different between the same gender subjects at URAS and control groups(P ＞ 0.05).(2) The genotype frequencies of MTRR A66G:the frequencies of genotype AA,AG and GG in URSA group were 57.0％ (114/200) in husband and 52.0％ (104/200) in wife,39.0％ (78/200) in husband and 41.5％ (83/200) in wife,4.0％ (8/200) in husband and 6.5％ (13/200) in wife,prepectively.The frequencies of genotype AA,AG and GG in control group were 59.2％ (45/76) in husband and 59.2％ (50/76) in wife,39.5％ (30/76) in husband and 38.2％ (29/76) in wife;1.3 ％ (1/76) in husband and 2.6％ (2/76) in wife,prepectively.The frequencies of genotype AA,AG and GG were not significantly different between female and male subjects within the same group (P ＞ 0.05),and also there were not significantly different between the same gender subjects at URSA and control groups (P ＞0.05).(3) Combined genotype of couples:the combined genotype frequencies of GG + GG,GG + AG,GG +AA,AG + AG,AG + AA and AA + AA in URSA group were 1.0％ (2/200),2.5％ (5/200),6.0％ (12/200),20.0％ (40/200),38.0％ (76/200),and 32.5 ％ (65/200),prepectively ; the combined genotype frequencies in control group were 0,1.3％ (1/76),2.6％ (2/76),17.1％ (13/76),42.1％ (32/76),36.8％ (28/76),prepectively.The combined genotype analysis between the two groups were also not significantly different (P ＞ 0.05).Conclusion The polymorphism of MTRR A66G gene was not associated with the susceptibility to URSA (P ＞ 0.05),and so it was not the inherited genetic risk factor of URSA.

Carcinogênese de cabeça e pescoço: impacto do polimorfismo MTHFD1 G1958A / Head and neck carconogenesis: impact of MTHFD1 G1958A polymorphism

OBJETIVO: Investigar o polimorfismo MTHFD1 G1958A envolvido no metabolismo do folato no risco para o câncer de cabeça e pescoço e verificar a associação entre esse polimorfismo com fatores de risco e características clínico-histopatológicas. MÉTODOS: Estudo retrospectivo que avaliou o polimorfismo MTHFD1 G1958A em 694 indivíduos (240 pacientes e 454 controles), por meio da técnica de análise de polimorfismo de comprimento de fragmento de restrição. Para análise estatística foram utilizados os testes de regressão logística múltipla e qui-quadrado. RESULTADOS: Tabagismo e idade superior a 42 anos foram preditores da doença (p < 0,05). Os genótipos MTHFD1 1958GA ou AA foram associados ao tabagismo (p = 0,04) e etilismo (p = 0,03) e estão presentes em maior proporção em tumores com estádios mais avançados (p = 0,04) e em pacientes com menor sobrevida (p = 0,03). CONCLUSÃO: A presença do polimorfismo MTHFD1 G1958A associada aos hábitos tabagista e etilista aumenta o risco para desenvolvimento de câncer de cabeça e pescoço.

OBJECTIVE: To investigate the MTHFD1 G1958A polymorphism involved in the folate metabolism as a risk for head and neck cancer, and to find the association of the polymorphism with the risk factors and clinical and histopathological characteristics. METHODS: Retrospective study investigating MTHFD1 G1958A polymorphism in 694 subjects (240 patients in the Case Group and 454 in the Control Group) by Restriction Fragment Length Polymorphism (RFLP) Analysis. Multiple logistic regression and chi-square tests were used in the statistical analysis. RESULTS: Multivariable analysis showed that smoking and age over 42 years were disease predictors (p < 0.05). MTHFD1 1958GA or AA genotypes were associated with smoking (p = 0.04) and alcoholism (p = 0.03) and were more often found in more advanced stage tumors (p = 0.04) and in patients with a shorter survival (p = 0.03). CONCLUSION: The presence of MTHFD1 G1948A polymorphism associated with smoking and alcoholism raises the head and neck cancer risk.

Metabolism and function of NADH and NADPH / 第二军医大学学报

In recent years, researchers have discovered that NADH and NADPH have important functions in physiological and pathological conditions. In this paper we discussed the synthesis and degradation of NADH and NADPH, focused on the function of NADH, NADPH and NADPH oxidase, and described their functions m various pathological conditions such as inflammation, cardiovascular disease, cancer, neurodegenerative diseases. Nowadays, the functions and metabolism of NADH (NADPH) have evoked international research interest; and the underlying mechanism will be better understood.

Effect of globular adiponectin on the function of NIT-I cells under high glucose medium / 中华内分泌代谢杂志

The effect of globular adiponectiin (gAd)on the function of NIT-1 cells under high glucose medium was investigated. The results showed that gad could completely block the increase of NADPH oxidase components p47phox expression and recover mRNA expression of pancreatic duodenal homeobox-I ,paired box gene 6,glucose transpoter 2,and glucokinase except neurogenic differentiation factor 1 (P<0.05 or P<0.01). Whereas,impaired insulin secretion and mRNA expression at high glucose concentration were not significantly improved by gAd.

Expression of NADP-dependent retinol dehydrogenase/reductase B1 in cervical squamous carcinoma cell line and antibody preparation / 解放军医学杂志

Objective The prokaryotic expression vector of NADP(H)-dependent retinol dehydrogenase/reductase(NRDR)B1 was constructed for the detection of NRDRB1 protein,and to prepare its polyclonal antibodies,in order to lay the foundation to study the function of NRDRB1.Methods The coding region of NRDRB1 was constructed to the Gateway-based expression vector(pDEST 14),which was transformed into the Escherichia coli(BL21-AI)for the native protein expression.Overexpression of the recombinant was induced at mid-log growth phase of BL21-AI(A600=0.6)using 0.2% L-arabinose.After supersonication the inclusion bodies of NRDRB1 were purified.New Zealand rabbits were immunized with NRDRB1 as the immunogen,which was recovered from SDS-PAGE gel and subscapsularly injected.The titer of the antiserum was determined by dot blot assay.The antibody was purified by HiTrap Protein G column,and its activity and specificity were assessed by Western blotting and immunohistochemistry.Results The prokaryotic expression vector pDEST 14 with NRDRB1 was constructed.The constructs were sequenced by dideoxynucleotide method.NRDRB1 was overexpressed in strain BL2l-AI.The concentration of recovered NRDRB1 was 0.42mg/ml with a recovery rate of 52.3%.All the immunized rabbits produced high-titer antisera after the second booster.The titer of the antiserum was 1∶2 000 with a detection limit of 6.4ng NRDRB1.The purified antibody had a high specificity.Conclusion The present study provides an effective method of preparing polyclonal antibody against NRDRB1.The purified NRDRB1 native protein and the specific polyclonal antibody of NRDRB1 would be valuable for the study on the biological function of NRDRB1.

Changes in insulin receptor, hexokinase and NADPH producing enzymes in Choroid plexus during experimental diabetes.

The activities of insulin receptor and the enzymes hexokinase (EC 2.7·1.1) and NADP-dependent malic enzyme (EC 1·1·1·40), glucose 6-phosphate dehydrogenase (EC 1·1·1·49) and isocitrate dehydrogenase (EC 1·1·1·42) were measured in rat choroid plexus in alloxan induced diabetes. A significant decrease was observed in the activities of all the enzymes except isocitrate dehydrogenase and also the choroid plexus insulin receptor activity was decreased. A reversal of the efect was observed with insulin administration to diabetic rats. It may be concluded that the enzymes of choroid plexus together with insulin receptor are directly controlled by-the concentration of insulin.