Environmental Stresses and Redox Status of Ascorbate

To investigate the effects of environmental stresses on ascorbic acid content and its redox status, the effects of freezing and drought on ascorbate and dehydro-ascorbate content and activities of four enzymes involved in the ascorbate-glutathione cycle in some conifers were studied. The results showed that both freezing and drought induced the decrease in ascorbate content and the increase in dehydro-ascorbate content. The activities of ascorbate peroxidase (APX) and monodehydro-ascorbate reductase (MDAR) were decreased by freezing stress. At the beginning of exposure to air, water loss from detached needles induced the increase in the activities of APX and MDAR. Further water loss turned to decrease the APX and MDAR activities. The activities of dehydro-ascorbate reductase (DHAR) and glutathione reductase (GR) were not sensitive to changes in temperature and water content of the needles. It is concluded that moderate temperature or water stresses may induce the acclimation and increase in the ability of the H2O2 scavenging system, while strong stresses decrease the ability and induce injury of plant tissues. Correlation between ascorbate content and activities of related enzymes and cold tolerance of conifers were also reported.

“社会主义市场经济”与“有计划商品经济”的关系

党的十四大提出:我国经济体制改革的目标,是建立社会主义市场经济体制.这里就提出一个问题。

环境卫生

0000002 对灾害医学未来所期待的[日]/千代谷庆三//日灾医志.-1998,46(8).-463～464 冀医情0000003 装具的开发[日]/福井信佳//日灾医志.-1998,46(6).-355～358冀医情0000004 自立和介助机器的开发[日]/松尾清美//日灾医志.-1998,46(6).-359～365

古币三考

一、"卤刀"新考天津历史博物馆藏有3枚所谓"西匕直刀"。这种刀形体较小,刀首尖,背微弧,刀身较窄,与赵国直刀相似,介于赵直刀与小型尖首刀之间。3枚刀的具体情况如下:1.通长11.9、最宽1.1、环径0.9厘米,面有2字。

Fragile X syndrome and epilepsy

Fragile X syndrome （FXS） is one of the most prevalent mental retardations. It is mainly caused by the loss of fragile X mental retardation protein （FMRP）. FMRP is an RNA binding protein and can regulate the translation of its binding RNA, thus regulate several signaling pathways. Many FXS patients show high susceptibility to epilepsy. Epilepsy is a chronic neurological disorder which is characterized by the recurrent appearance of spontaneous seizures due to neuronal hyperactivity in the brain. Both the abnormal activation of several signaling pathway and morphological abnormality that are caused by the loss of FMRP can lead to a high susceptibility to epilepsy. Combining with the research progresses on both FXS and epilepsy, we outlined the possible mechanisms of high susceptibility to epilepsy in FXS and tried to give a prospect on the future research on the mechanism of epilepsy that happened in other mental retardations.

Shift work aggravates metabolic syndrome development among early-middle-aged males with elevated ALT

AIM: To examine whether shift work accelerates metabolic syndrome (MetS) development among early middle-aged males with elevated alanine aminotransferase (e-ALT).METHODS: A retrospective, observational followup study on MetS development at a 5-year interval was conducted using health examination data. Nine hundred and ninety six male employees not fulfi lling MetS criteria at screening were enrolled. Age, MetScomponents, liver enzymes, serological markers for viral hepatitis, abdominal ultrasound, insulin resistance status, lifestyles, and workplace factors were analyzed.RESULTS: The prevalence of elevated serum ALT (> 40 U/L, e-ALT) at baseline was 19.1%. There were 381 (38.3%) workers with long-term exposures to day-night rotating shift work (RSW). 14.2% of subjects developed MetS during follow-up. After 5 years, the workers with e-ALT had significantly unfavorable changes in MetS-components, and higher rates of MetS development, vs subjects with normal baseline ALT levels. Workers with both baseline e-ALT and 5-year persistent RSW (pRSW) exposure had the highest rate of MetS development. Also, e-ALT-plus-pRSW workers had a significant increase in MetS-components atfollow-up, compared with the other subgroups. After controlling for potential confounders, e-ALT-plus-pRSW workers posed a signifi cant risk for MetS development (odds ratio, 2.7; 95% confi dence interval, 1.4-5.3, vs workers without baseline e-ALT nor pRSW). CONCLUSION: We suggest that all early middle-aged male employees with e-ALT should be evaluated and managed for MetS. Particularly in terms of job arrangements, impacts of long-term RSW on MetS development should be assessed for all male employees having baseline e-ALT.

Metabolic syndrome is directly associated with gamma glutamyl transpeptidase elevation in Japanese women

AIM:This study aimed to determine whether metabolic syndrome is directly or indirectly,through fatty liver,associated with elevated gamma-glutamyl transpeptidase (GGT) levels in Japanese women. METHODS:From 4 366 women who received their annual health check-up,4 211 women were selected for analysis. All 4 211 women were negative for both hepatitis B surface antigen and antibody to hepatitis C virus.Clinical and biochemical variables were examined by using univariate and multivariate analysis. RESULTS:A raised GGT level (>68 IU/L) was seen in 258 (6.1%) of the 4 211 women.In univariate analysis,all variables examined (age,body mass index,blood pressure, hemoglobin concentration,fasting blood glucose, glycosylated hemoglobin Alc,cholesterol,triglyceride,and uric acid) were associated with the elevated GGT level, whereas in multivariate analysis,four variables (age≧50 yr, hemoglobin≧14 g/dL,triglyceride≧150 mg/dL,and presence of diabetes) were significantly and independently associated with raised GGT level.Clinical variables predicting the presence of ultrasonographic evidence of fatty liver were also examined by multivariate analysis;four variables were associated with the presence of fatty liver:BMI≧25 kg/m^2, hemoglobin≧14 g/dL,triglyceride≧150 mg/dL,and uric acid ≧ 7 mg/dL.There was no significant association between the raised GGT level and the presence of fatty liver. Hypertriglyceridemia was significantly and independently associated with both the raised GGT level and the presence of fatty liver. CONCLUSION:Metabolic syndrome seemed to be directly, not indirectly through fatty liver,associated with the raised GGT level in Japanese women.

Associations between y-glutamyl transferase, metabolic abnormalities and inflammation in healthy subjects from a population-based cohort: A possible implication for oxidative stress

AIM: To examine the relationships between γ -glutamyltransferase (GGT), alanine-aminotransferase (ALT),aspartate-aminotransferase (AST) and various metabolic parameters, C-reactive protein (CRP) and an oxidative stress marker (nitrotyrosine, NT) in subjects without any metabolic abnormalities from a population-based sample.METHODS: Two hundred and five subjects with normal body mass index (BMI), glucose tolerance, and without any metabolic abnormality were studied out of 1339subjects, without known liver diseases, alcohol abuse or use of hepatotoxic drugs, who are representative of the 45-64 aged population of Asti (north-western Italy).RESULTS: In all patients metabolic parameters and hs-CRP levels linearly increase from the lowest to the highest ALT and GGT tertiles, while in subjects without metabolic abnormalities, there is a significant association between fasting glucose, uric acid, waist circumference,hs-CRP, triglyceride values, and GGT levels. In these subjects, male sex, higher hs-CRP and glucose levels are associated with GGT levels in a multiple regression model, after adjustments for multiple confounders.In the same model, median NT levels are significantly associated with the increasing GGT tertile (β = 1.06;95%CI 0.67-1.45), but not with the AST and ALT tertiles.In a multiple regression model, after adjusting for age,sex, BMI, waist, smoking, and alcohol consumption, both NT (β = 0.05; 95%CI 0.02-0.08) and hs-CRP levels (β =0.09; 95%CI 0.03-0.15) are significantly associated with fasting glycemia.CONCLUSION: GGT, an easy, universally standardized and available measurement, could represent an early marker of sub-clinical inflammation and oxidative stress in otherwise healthy individuals. Prospective studies are needed to establish if GGT could predict future diabetes in these subjects.

Progression of diethylnitrosamine-induced hepatic carcinogenesis in carnitine-depleted rats

AIM:To investigate whether carnitine deficiency is a risk factor during the development of diethylnitrosamine (DENA)-induced hepatic carcinogenesis. METHODS:A total of 60 male Wistar albino rats were divided into six groups with 10 animals in each group.Rats in group 1(control group)received a single intraperitoneal(i.p.)injection of normal saline. Animals in group 2(carnitine-supplemented group) were given L-carnitine(200 mg/kg per day)in drinking water for 8 wk.Animals in group 3(carnitine-depleted group)were given D-carnitine(200 mg/kg per day)and mildronate(200 mg/kg per day)in drinking water for 8 wk.Rats in group 4(DENA group)were injected with a single dose of DENA(200 mg/kg,i.p.)and 2 wk later received a single dose of carbon tetrachloride(2 mL/kg) by gavage as 1:1 dilution in corn oil.Animals in group 5(DENA-carnitine depleted group)received the same treatment as group 3 and group 4.Rats in group 6 (DENA-carnitine supplemented group)received the same treatment as group 2 and group 4.RESULTS:Administration of DENA resulted in a significant increase in alanine transaminase(ALT), gamma-glutamyl transferase(G-GT),alkaline phosphatase(ALP),total bilirubin,thiobarbituric acid reactive substances(TBARS)and total nitrate/ nitrite(NOx)and a significant decrease in reduced glutathione(GSH),glutathione peroxidase(GSHPx), catalase(CAT)and total carnitine content in liver tissues.In the carnitine-depleted rat model,DENA induced a dramatic increase in serum ALT,G-GT,ALP and total bilirubin,as well as a progressive reduction in total carnitine content in liver tissues.Interestingly, L-carnitine supplementation resulted in a complete reversal of the increase in liver enzymes,TBARS and NOx,and a decrease in total carnitine,GSH,GSHPx, and CAT induced by DENA,compared with the control values.Histopathological examination of liver tissues confirmed the biochemical data,where L-carnitine prevented DENA-induced hepatic carcinogenesis while D-carnitine-mildronate aggravated DENA-induced hepatic damage. CONCLUSION:Data from this study suggest for the first time that:(1)carnitine deficiency is a risk factor and should be viewed as a mechanism in DENA- induced hepatic carcinogenesis;(2)oxidative stress plays an important role but is not the only cause of DENA-induced hepatic carcinogenesis;and(3) long-term L-carnitine supplementation prevents the development of DENA-induced liver cancer.

英语谚语语法结构及修辞方式初探

谚语是民间文学的一个宝库,不论古今中外,流传广泛的谚语一般都具有简明、通俗、隽永、生动等特点。由于谚语先是在人民群众的口语中辗转相授,经过长期锤炼,因此它具有很强的生命力。

Effect of catgut implantation at acupoints on GABA_B and mGluR1 expressions in brain stem of rats with spasticity after stroke

OBJECTIVE: To investigate the effect of catgut implantation at acupoints on the expressions of γ-amino butyric acid B receptor(GABAB ) and metabotropic glutamate receptor 1(mGluR1) in the brain stem of rats with spasticity after stroke.METHODS: In total, 60 male Sprague-Dawley rats were randomly divided into three groups: a sham group(n=10), a model group(n=25) and a treatment group(n=25). The rats in both the model group and the treatment group were subjected to middle cerebral artery occlusion to establish a model of focal cerebral ischemia. Rats with limb-spasm met the inclusion criteria. Only the left carotid artery was isolated in sham group rats. Three days after modeling, the treatment group was subjected to catgut implantation at Dazhui(GV 14), Guanyuan(CV 4), and Zhongwan(CV 12). Neurological deficit symptoms were assessed with the Zea-Longa neurological deficit score. The Modified Ashworth Scale(MAS), and isolated muscle tone were used to evaluate spasticity before and after treatment. Immunohistochemistry was applied to determine the expression of GABAB and mGluR1 in the rat brain stem after treatment.RESULTS: After treatment, neural impairment symptoms had significantly improved in the treatment group when compared to the model group(P<0.05). Both MAS and isolated muscle tone in the treatment group were significantly decreased when compared with the model group(P<0.05),and were also lower than before treatment. GABAB expression was significantly higher and mGluR1 was lower in the treatment group when compared with the model group(P<0.01 and P<0.05, respectively).CONCLUSION: Catgut implantation at Dazhui(GV 14), Guanyuan(CV 4), and Zhongwan(CV 12), can relieve limb spasticity by increasing the expression of GABAB and reducing the expression of mGluR1 in the brain stem of rats after stroke.

Characterization of Nitrogen Metabolism in the Low-Nitrogen Tolerant lnt1 Mutant of Arabidopsis thaliana Under Nitrogen Stress

A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen （N） metabolism of a low-N tolerant mutant （lntl） of Arabidopsis thaliana under different N levels as compared with the wild- type （WT） Arabidopsis. On the agar medium, no apparent growth differences were observed between the lntl and WT plants under a normal N level of 9 mmol L^-1 NO3. However, under a low N level of 0.18 mmol L^-1 NO3^-, the growth of the WT plants was greatly retarded, while the lntl plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lntl mutant had higher activities of glutamine synthetase （GS） and NADH-dependent glutamate synthase （NADH-GOGAT） in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium （NH4^＋） but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.

Changes of metabotropic glutamate receptor subtype 1a in diffuse brain injury with secondary brain insults and the effects of 2-methyl-4-carboxyphenylglycine

Objective: To observe the changes of metabotropic glutamate receptor 1a in rat brain in a rodent model of diffuse head injury with secondary insults and the effects of 2 methyl 4 carboxyphenylglycine (MCPG). Methods: Based on Marmarous rodent model of diffuse brain injury (DBI), hypotension was made by blood withdrawal as secondary brain insults (SBI). 105 male SD rats were randomized into A and B groups. The changes of mGluR 1a in cerebral cortex were studied by immunohistochemistry and the effect of MCPG by HE. Each group was divided into different subgroups at different time after injury. Results: Compared with that of sham group, the number of mGluR 1a positive neuron increased by 12.9±3.2 (P< 0.05 ) 1 day after injury in the injured cerebral cortex in DBI group. However, in DBI and SBI group there was a more significant increase in the number of mGluR 1a positive neuron at 4 hours after injury ( 15.6±3.0 , P< 0.05 )and then the number of mGluR 1a positive neuron gradually decreased. Administration of MCPG reduced total cortical necrotic neurons counts on the 7th day after injury ( 5.21±2.52 , P< 0.05 ). Conclusions: Brain injury can increase the gene expression of mGluR 1a and the role of mGluR 1a may be a key factor in the aggravation of head injury with SBI, and that MCPG may have therapeutic potential in head injury.

Soil Salinity Changes in the Jordan Valley Potentially Threaten Sustainable Irrigated Agriculture

The integrated effect of irrigation and agricultural practices on soil salinity in the Jordan Valley （JV）, where over 60% of Jordan＇s agricultural produce is grown, was investigated in this study during 2009-2010. Due to the differences in agricultural operations, cropping patterns, irrigation management, and weather conditions, 206 top- and sub-soil samples were taken every 1 to 3 km from representative farms along a north-south （N-S） transect with 1 to 2 km lateral extents. Soil electrical conductivity of saturated extract （ECse）, Ca, Mg, K, Na, CI, and Na adsorption ratio （SAR） were determined in saturated paste extracts. Results indicated that about 63% of soils in the JV are indeed saline, out of which almost 46% are moderately to strongly saline. Along the N-S transect of the JV, ECse increased from 4.5 to 14.1 dS m-1 in top-soil samples. Similar increase was observed for the sub-soil samples. The major chemical components of soil salinity; i.e., Ca, Mg, and C1, also showed a similar increase along the N-S transect of the valley. Moreover, compared to previous field sampling, results showed that changes in soil salinity in the JV were dramatic. In addition, it was found that C1 imposed an existing and potential threat to sensitive crops in 60% of the soils in the JV, where C1 concentrations were greater than 710 mg L-1. Under the prevalent arid Mediterranean conditions, improving the management of .irrigation water, crops, and nutrient inputs and increasing water and fertilizer use efficiencies should be indispensable to conserve and sustain the already fragile agricultural soils in the JV.

Effect of neuronal excitotoxicity on Munc18-1 distribution in nuclei of rat hippocampal neuron and primary cultured neuron

Objective Muncl8-1 has an important role in neurotransmitter release, and controls every step in the exocy- totic pathway in the central nervous system. In the present study, whether epileptic seizure causes a change of Muncl8 localization in neuronal nuclei was analyzed. Methods Epilepsy models were established by injection of kainic acid （KA） solution into hippocampus of Sprague-Dawley （SD） rats or intraperitoneal injection of KA in Kunming mice. The hippocampal neurons were prepared from embryonic day 18 SD rats, and cultured in neurobasal medium, followed by treatment with glutamate for 3 h. Neuronal and glial nuclei of hippocampus were separated by sucrose density gradient centrifugation. The nucleus-enriched fractions were stained with 0.1% Cresyl Violet for morphological assay. Immuno- chemistry and immunoelectron microscopy with anti-Muncl 8-1 antibody were used to determine the nuclear locatization of Munc 18-1. Immunoblotting was used to detect the protein level of Munc 18-1. Results The localization of Munc 18-1 in nucleus of rat hippocampal neuron was confirmed by immunochemistry, immunoelectron microscopy, and immunob- lotting detection of neuronal nucleus fraction. In animals receiving intrahippocampal or intraperitoneal injection of KA, immunostaining revealed that the expression of Muncl 8-1 decreased in pyramidal cell layer of CA regions, as well as in hilus and granular cell layer of dentate gyrus in hippocampus. Moreover, immunoblotting analysis showed that the expres- sion level of Muncl 8-1 in nucleus fraction of hippocampus significantly decreased in KA-treated animals. The relation- ship between the change of Muncl8-1 expression in neuronal nuclei and neuronal over-activation was also tested in pri- mary cultured neurons. After treatment with 50 ~tmol/L glutamate acid for 3 h, Muncl8-1 level was decreased in nucleus fraction and increased in cytoplasmic fraction of primary cultured neurons. Conclusion These results suggest that excit- atory stimulation can induce the distribution change of Munc 18-1 in neuron, which may subsequently modulate neuronal functions in brain.

Opening time and filling pattern of the Neoproterozoic Kangdian Rift Basin,western Yangtze Continent,South China

The Neoproterozoic Kangdian Rift Basin is a continental rift basin in the western Yangtze Continent.Determining its time of opening and subsequent filling pattern is an important aspect of understanding the formation and evolution of the Yangtze Continent,South China.The Luliang Formation is the early filling in the eastern part of this rift basin,and its deposition age and filling sequence are significant for studies of the regional stratigraphic correlation,opening time,and filling pattern of this basin.Having been correlated to the upper part of the Mesoproterozoic Kunyang Group or to the Neoproterozoic Chengjiang Formation,the age and regional stratigraphic correlation of the Luliang Formation have long been uncertain.This is due to a lack of reliable absolute age constraints.To address this issue,the first zircon SHRIMP U-Pb geochronology has been established for this formation,yielding two high-precision isotopic ages of 818.6±9.2 and 805±14 Ma for the tuff layers at the bottoms of the lower and upper members of the Luliang Formation,respectively.Given the error factor,the bottom age of the lower member of the Luliang Formation can be interpreted as ca.820 Ma,corresponding to the bottom age of the lower part of the Banxi Group,which is the early filling of the Neoproterozoic Xianggui Rift Basin,a representative basin of the Neoproterozoic rift basins in the Yangtze Continent,South China.The bottom age of the upper member of the Luliang Formation can be interpreted as ca.800±5 Ma,corresponding to the bottom age of the Chengjiang Formation in the western part of the Neoproterozoic Kangdian Rift Basin and also corresponding to the bottom age of the upper part of the Banxi Group in the Neoproterozoic Xianggui Rift Basin.These ages indicate that the Neoproterozoic Kangdian Rift Basin shares the same opening time and filling sequences as those of the other Neoproterozoic rift basins in South China.Basin analysis shows that the Neoproterozoic Kangdian Rift Basin is a typical half-graben basin,with its main boundary fault in the west and basin center in the east.This basin consisted of mini unidirectional half-graben basins in its juvenile stage and simplified to become a large united half-graben basin in its mature stage,i.e.,a supradetachment basin.

Metabolic engineering and flux analysis of Corynebacterium glutamicum for L-serine production

L-Serine plays a critical role as a building block for cell growth, and thus it is difficult to achieve the direct fermentation of L-serine from glucose. In this study, Corynebacterium glutamicum ATCC 13032 was engineered de novo by blocking and at- tenuating the conversion of L-serine to pyruvate and glycine, releasing the feedback inhibition by L-serine to 3-phosphoglycerate dehydrogenase （PGDH）, in combination with the co-expression of 3-phosphoglycerate kinase （PGK） and feedback-resistant PGDH （PGDHr）. The resulting strain, SER-8, exhibited a lower specific growth rate and significant differ- ences in L-serine levels from Phase I to Phase V as determined for fed-batch fermentation. The intracellular L-serine pool reached （14.22_＋1.41） ~trnol gcoM-1, which was higher than glycine pool, contrary to fermentation with the wild-type strain. Furthermore, metabolic flux analysis demonstrated that the over-expression of PGK directed the flux of the pentose phosphate pathway （PPP） towards the glycolysis pathway （EMP）, and the expression of PGDHr improved the L-serine biosynthesis pathway. In addition, the flux from L-serine to glycine dropped by 24%, indicating that the deletion of the activator GlyR re- sulted in down-regulation of serine hydroxymethyltransferase （SHMT） expression. Taken together, our findings imply that L-serine pool management is fundamental for sustaining the viability of C. glutamicum, and improvement of C1 units genera- tion by introducing the glycine cleavage system （GCV） to degrade the excessive glycine is a promising target for L-serine pro- duction in C. glutamicum.

Fatty acid metabolism and cancer development

Although the type and etiology of cancers are different, pathways in glucose metabolism, pentose phos- phate pathway （PPP） and glutamine metabolism have been reprogrammed in cancer cells to adapt to their rapid growth and proliferation. Recent research has also shown that mul- tiple lipid metabolic pathways are altered in cancer cells. Here, we provide a brief review for the role of fatty acid metabolism in cancer development with a special focus on fatty acid uptake and de novo synthesis, triglycerides syn- thesis, storage and degradation. Reprogramming in fatty acid metabolism plays important roles in providing energy, macromolecules for membrane synthesis and lipid signals during cancer development. Understanding the mechanism of deregulated lipid metabolic pathways in cancer cells would reveal novel therapeutic approaches to combat cancer.

Changes in metabotropic glutamate receptor 4 expression and the effects of L-2-amino-4-phosphonobutyrate in a rodent model of diffuse brain injury

Objective: To examine the changes in the express ion of mGluR4 after diffuse brain injury (DBI) and to determine the role of its specific agonist L-2-amino-4-phosphonobutyrate (L-AP4) in vivo. Methods: A total of 161 male SD rats were randomized into the f ollowing groups. Group A included normal control,sham-operated control and DBI group. DBI was produced according to Marmarous diffuse head injury model. mRN A expression of mGluR4 was detected by hybridization in situ. Group B included D BI alone,DBI treated with normal saline and DBI treated with L-AP4. All DBI ra ts were trained in a series of performance tests,following which they were subj ected to DBI. At 1 and 12 hours,animals were injected intraventricularly with L -AP4 ( 100 mmol/L ,10 μl) or normal saline. Motor and cognitive performance s were tested at 1,3,7,14 days after injury and the damaged neurons were also detected. Results: There was no significant difference between normal con trol group and sham-operated group in the expression of mGluR4 ( P > 0.05 ) . The animals exposed to DBI showed significantly increased expression of mRNA o f mGluR4 compared with the sham-operated animals 1 h after injury ( P < 0.05 ). At 6 hours,the evolution of neuronal expression of mGluR4 in the trauma al one group was relatively static. Compared with saline-treated control animals,rats treated with L-AP4 showed an effective result of decreased number of damag ed neurons and better motor and cognitive performances.Conclusions: Increased expression of mGluR4 is important in the pathophysiological process of DBI and its specific agonist L-AP4 can provide r emarkable neuroprotection against DBI not only at the histopathological level bu t also in the motor and cognitive performance.