Molecular modification and biotechnological applications of microbial aspartic proteases.

The growing preference for incorporating microbial aspartic proteases in industries is due to their high catalytic function and high degree of substrate selectivity. These properties, however, are attributable to molecular alterations in their structure and a variety of other characteristics. Molecular tools, functional genomics, and genome editing technologies coupled with other biotechnological approaches have aided in improving the potential of industrially important microbial proteases by addressing some of their major limitations, such as: low catalytic efficiency, low conversion rates, low thermostability, and less enzyme yield. However, the native folding within their full domain is dependent on a surrounding structure which challenges their functionality in substrate conversion, mainly due to their mutual interactions in the context of complex systems. Hence, manipulating their structure and controlling their expression systems could potentially produce enzymes with high selectivity and catalytic functions. The proteins produced by microbial aspartic proteases are industrially capable and far-reaching in regulating certain harmful distinctive industrial processes and the benefits of being eco-friendly. This review provides: an update on current trends and gaps in microbial protease biotechnology, exploring the relevant recombinant strategies and molecular technologies widely used in expression platforms for engineering microbial aspartic proteases, as well as their potential industrial and biotechnological applications.

Type 2 sclerotic Modic change affect fusion result in patients undergoing PLIF with pedicle screw instrumentation: a retrospective study.

BACKGROUND: Bony fusion rate was significantly lower in patients with type 3 Modic change than patients with normal endplates. It is not known whether there are relevant differences in fusion efficiency among patients with type 2 sclerotic Modic change or non-sclerotic Modic change, or no Modic change. METHODS: A retrospective study contained 196 lumbar segments in 123 subjects undergoing posterior lumbar interbody fusion (PLIF) with pedicle screw instrumentation (PSI) to assess the effect of type 2 sclerotic Modic change on fusion efficiency. These endplates were allocated into groups A, B, and C, according to their Modic changes. Group A had endplates with type 2 Modic change and endplate sclerosis. Group B had type 2 Modic change without endplate sclerosis. Group C had neither Modic change nor endplate sclerosis. The presence of Modic change was determined by magnetic resonance imaging (MRI). Endplate sclerosis in type 2 Modic change was detected by computed tomography (CT) before the operation. We collected CT data 3 months to more than 24 months after operation in patients to assess bony fusion. RESULTS: Incidences of bony fusion were 58.8% in group A, 95.0% in group B, 94.3% in group C. The bony fusion rate was significantly lower in group A than in either group B or C. There was no significant difference between groups B and C. Thus, endplates with type 2 sclerotic Modic change had a lower fusion rate in patients undergoing PLIF with PSI. CONCLUSION: Type 2 sclerotic Modic change could be an important factor that affects solid bony fusion in patients undergoing PLIF with PSI. CT may help diagnose endplate sclerosis in patients with type 2 change and inform the choice of the best site for spinal fusion.

[Clinical observation of herb-separated moxibustion on segmental conception vessel combined with low-frequency TEAS for asthenospermia and oligospermia].

OBJECTIVE: To observe the clinical effect of herb-separated moxibustion on segmental conception vessel combined with low-frequency transcutaneous electrical acupoint stimulation (TEAS) for asthenospermia and oligospermia. METHODS: A total of 105 patients with asthenospermia and oligospermia were randomly divided into a combination group, a TEAS group and a medication group, 35 cases in each one. In the medication group, vitamin E capsules, coenzyme Q10 capsules，Wuzi Yanzong pills were taken. In the TEAS group, TEAS was applied at Shenshu (BL 23) and Pishu (BL 20), 2 Hz in frequency, 10-15 mA in intensity, once every 2 days, 30 min each time.On the base of the treatment as the TEAS group, herb-separated moxibustion on segmental conception vessel [Shenque (CV 8) to Zhongji (CV 3)] was applied in the combination group, once every 10 days. A total of 3 months were required in the 3 groups.Before treatment and 2, 3 months into treatment, the semen routine indexes (concentration, normal morphology rate, sperm motility), seminal plasma contents of superoxide dismutase (SOD) and malondialdehyde (MDA) and TCM syndrome score were observed in the 3 groups, and the clinical efficacy was evaluated. RESULTS: Compared before treatment, except for the sperm morphology 2 months into treatment in the medication group, the semen routine indexes 2, 3 months into treatment were improved in the 3 groups (P<0.01), and the semen routine indexes 2, 3 months into treatment in the combination group were superior to the medication group and the TEAS group (P<0.01). Compared before treatment, the seminal plasma contents of SOD were increased and MDA were decreased 2, 3 months into treatment in the 3 groups (P<0.01), and the changes of the combination group were larger than the medication group and the TEAS group (P<0.01). Compared before treatment, the TCM syndrome scores 2, 3 months into treatment in the combination group, and 3 months into treatment in the medication group and the TEAS group were decreased (P<0.01). The TCM syndrome scores 2, 3 months into treatment in the combination group were lower than the medication group and the TEAS group (P<0.01). The total effective rates in the combination group, the medication group and the TEAS group were 85.7% (30/35), 68.6% (24/35) and 65.7% (23/35), the clinical efficacy of the combination group was higher than the medication group and the TEAS group (P<0.05). CONCLUSION: Herb-separated moxibustion on segmental conception vessel combined with low-frequency TEAS can improve semen routine, reduce sperm oxidative stress damage for patients with asthenospermia and oligospermia, and the clinical efficacy is better than the medication and TEAS.

Heat-induced oxidative stress and inflammation involve in cadmium pollution history in the spleen of zebrafish.

Zebrafish were exposed to 0, 2.5 and 5 µg/L cadmium (Cd) for 10 weeks, and then each group was exposed to 26 °C(control) and 32 °C (high temperature) for 7 days. 22 indicators were compared between 26 °C and 32 °C in the spleen, including body weight, LPO and NO levels, activity levels of Cu/Zn-SOD, CAT and iNOS, MTs protein levels, and mRNA levels of Nrf2, Cu/Zn-SOD, CAT, HSF1, HSF2, HSP70, MTF-1, MTs, IL-6, IL-10, IL-1ß, TNF-α, iNOS and NF-κB. Most indicators were not significantly affected by heat in fish from no Cd pollution. However, almost all of indicators were responsive to heat in fish pre-exposed to Cd. Several indicators were sensitive to heat in fish pre-exposed to 2.5 µg/L Cd such as iNOS activities, and mRNA levels of iNOS and IL-10. Most other indicators were sensitive to heat in fish pre-exposed to 5 µg/L. The mRNA levels of HSP70 and MTF-1 were up-regulated by heat in fish pre-exposed to 0, 2.5 and 5 µg/L Cd. However, the magnitude of increase was the greatest in fish pre-exposed to 5 µg/L Cd. These differences between control and high temperature would serve as biomarkers to distinguish healthy from Cd-polluted group. The findings imply that metal pollution history should be carefully considered when screening heat biomarkers in fish.

Effects of heat and cadmium exposure on stress-related responses in the liver of female zebrafish: Heat increases cadmium toxicity.

In this study, female zebrafish (Danio rerio) were exposed to 26°C or 34°C, 0 or 197µg/L cadmium (Cd), singly or in combination for 7days. Multiple stress-related indicators were evaluated in the liver. Mortality, lipid peroxidation (LPO) and ultrastructural damage increased significantly by Cd exposure alone, and were not affected by heat alone. Interestingly, the combined exposure increased LPO, ultrastructural damage, and mortality compared with Cd exposure alone. The results indicated that elevated temperature increased Cd toxicity, which could be explained by several reasons. Firstly, Cd-exposed fish failed to activate the antioxidant defense system under heat stress. Secondly, expression levels of heat shock protein 70 (HSP70) were not significantly up-regulated by heat in Cd-exposed fish but increased by 117 times in Cd-free fish. Besides, hypermethylation of heat shock factor (HSF) binding motif in HSP70 promoter was observed during the combined exposure, indicating that simultaneous exposure may have partially suppressed the cytoprotective up-regulation of HSP70. Thirdly, heat induced an immunosuppressive effect in Cd-exposed fish, as reflected by the reduced mRNA and activity levels of nitric oxide synthase (iNOS) and interleukin-1ß (IL-1ß) expression levels. Finally, heat down-regulated Zir-, Irt-like protein 8 (ZIP8) and copper transporter 1 (CTR1) and up-regulated metallothioneins (MTs) in Cd-exposed fish, possibly suggesting Cu and Zn depletion and Cd accumulation. Hence, our data provide evidences that warmer temperatures can potentiate Cd toxicity, involved in the regulation of gene transcription, enzymatic activity, and DNA methylation. We found that heat indicators showed varied sensitivity between normal and Cd-exposed fish, emphasizing that the field metal pollution should be carefully considered when evaluating effects of climate change.

Heat indicators of oxidative stress, inflammation and metal transport show dependence of cadmium pollution history in the liver of female zebrafish.

Environmental stressors such as high temperature and metal exposure may occur sequentially, simultaneously, previously in aquatic ecosystems. However, information about whether responses to high temperature depend on Cd exposure history is still unknown in fish. Zebrafish were exposed to 0 (group 1), 2.5 (group 2) and 5µg/L (group 3) cadmium (Cd) for 10 weeks, and then each group was subjected to Cd-free water maintained at 26°C and 32°C for 7days respectively. 26 indicators were used to compare differences between 26°C and 32°C in the liver of female zebrafish, including 5 biochemical indicators (activity of Cu/Zn-SOD, CAT and iNOS; LPO; MT protein), 8 molecular indicators of oxidative stress (mRNA levels of Nrf2, Cu/Zn-SOD, CAT, HSF1, HSF2, HSP70, MTF-1 and MT), 5 molecular indicators of inflammation (mRNA levels of IL-6, IL-1ß, TNF-α, iNOS and NF-κB), 8 molecular indicators of metal transport (mRNA levels of, ZnT1, ZnT5, ZIP8, ZIP10, ATP7A, ATP7B and CTR1). All biochemical indicators were unchanged in group 1 and changed in group 2 and 3. Contrarily, differences were observed in almost all of molecular indicators of inflammation and metal transport in group 1, about half in group 2, and few in group 3. We also found that all molecular indicators of oxidative stress in group 2 and fewer in group 1 and 3 were significantly affected by heat. Our data indicated that heat indicators of oxidative stress, inflammation and metal transport showed dependence of previous cadmium exposure in the liver of zebrafish, emphasizing metal pollution history should be carefully considered when evaluating heat stress in fish.

Preheating mitigates cadmium toxicity in zebrafish livers: Evidence from promoter demethylation, gene transcription to biochemical levels.

The working hypothesis for this study was that moderate heat stress would alleviate the deleterious effects of subsequent cadmium (Cd) exposure on fish. Thus, zebrafish (Danio rerio) were subjected to water maintained at 26°C and 34°C for 4days, and then exposed to 0 or 200µg/L Cd for 1 week at 26°C. Multiple indicators were measured from livers of zebrafish at different levels, including DNA, RNA, protein and enzymatic activity associated with oxidative stress, inflammation and metal transport. The ameliorative effect of preheatinging on Cd toxicity was demonstrated. In the Cd-exposed groups, preheating decreased mortality and lipid peroxidation, increased activity levels of catalase (CAT) and copper/zinc-superoxide dismutase (Cu/Zn-SOD), and up-regulated mRNA levels of heat shock protein 70 (HSP70) and heat shock factor 2 (HSF2). Preheating also mitigated Cd-induced increases in protein and mRNA levels of metallothioneins (MTs), and mRNA levels of several inflammation-related genes. Furthermore, preheating alone dramatically up-regulated mRNA levels of genes related to antioxidant and immune defenses, zinc and copper transporters, protein folding, and reduced methylation levels in the HSF binding motif of the HSP70 promoter. Overall, preheating-induced accumulation of transcripts via demethylation might support the rapid defense responses at post-transcriptional levels caused by subsequent Cd exposure, indicating an adaptive mechanism for organisms exposed to one mild stressor followed by another.

Immunosuppressive effects and associated compensatory responses in zebrafish after full life-cycle exposure to environmentally relevant concentrations of cadmium.

In natural environments, fish survive in polluted water by cadmium (Cd) throughout their whole life cycle. However, little information is available on Cd toxicity considering a life cycle assessment. The present study investigated effects of environmental levels of cadmium (0, 2.5, and 5µg/L) on immune responses in liver and spleen of zebrafish for 15 weeks, from embryos to sexually maturity. Nitric oxide (NO) levels and iNOS activity declined in liver and spleen of zebrafish exposed to 5µg/L Cd, suggesting an immunosuppressive effect. The result was further supported by the decreased transcriptional levels of proinflammatory cytokines by Cd, such as interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-1ß (IL-1ß), and tumour necrosis factor-α (TNF-α) in liver. However, a sharp increase in the mRNA levels of these cytokines was observed in spleen of zebrafish exposed to Cd. The increased mRNA expression of these proinflammatory cytokines may be the secondary effect following immunosuppression and just reflect a compensatory mechanism for coping with the decreased immunity, which may explain an increase in mRNA levels and a decrease in iNOS activity in spleen of zebrafish exposed to Cd. In liver, the down-regulated mRNA levels of iNOS paralleled with the decreased iNOS activity, suggesting a synchronous response from a molecular level to a biochemical level. Positive correlations between mRNA expression levels of nuclear transcription factor κB (NF-κB) and proinflammatory cytokines were also observed, suggesting that NF-κB might be required for the protracted induction of inflammatory genes. The corresponding changes in the mRNA levels of the inhibitor of κBα (IκBαa and IκBαb) may form a feedback loop to restore transcriptional activity of NF-κB. Furthermore, splenic ROS levels were increased by 5µg/L Cd, possibly activating NF-κB pathway. Taken together, immunosuppressive effects and tissue-dependent compensatory responses were demonstrated in zebrafish after full life-cycle exposure to environmental levels of Cd, indicating a compromise between survival and immunity.

Negative effect of chronic cadmium exposure on growth, histology, ultrastructure, antioxidant and innate immune responses in the liver of zebrafish: Preventive role of blue light emitting diodes.

The present study explored the possible preventive effects of blue light emitting diodes (LEDs) on cadmium (Cd)-induced oxidative stress and immunotoxicity in zebrafish. To this end, zebrafish were exposed to a white fluorescent bulb or blue LEDs (LDB, peak at 450nm, at an irradiance of 0.9W/m2), and 0 or 30µgL-1 waterborne Cd for 5 weeks. Growth performance, survival rate, and hepatic histology, ultrastructure, antioxidant and innate immune responses were determined in zebrafish. Cd exposure alone reduced growth and survival rate, and induced oxidative damage and changes in histology and ultrastructure. However, Cd exposure in combination with LDB apparently relieved these negative effects. The alleviation of adverse effects might result from the up-regulation of antioxidant and innate immune genes at transcriptional, translational, or post-translational levels. Cd exposure alone dramatically enhanced mRNA levels of nuclear transcription factor κB (NF-κB) and E2-related factor (Nrf2). However, compared to Cd exposure alone, Cd exposure in combination with LDB apparently down-regulated both genes. Taken together, our results suggest that chronic Cd exposure induced a negative effect on zebrafish, possibly involved in NF-κB-induced immunotoxicity and Nrf2-induced oxidative stress. Finally, for the first time, our data demonstrated that LDB could protect fish against Cd toxicity.

Different effects of blue and red light-emitting diodes on antioxidant responses in the liver and ovary of zebrafish Danio rerio.

The present study assessed the effects of a white fluorescent bulb (the control) and two different light-emitting diodes (blue LEDs, LDB; red, LDR) on growth, morphology, and oxidative stress in the liver and ovary of zebrafish for 5 weeks. Growth maintained relatively constant under LDB condition, but was reduced under LDR condition. In the liver, hepatosomatic index (HSI) and protein carbonylation (PC) increased under LDR condition, whereas lipid peroxidation (LPO) declined and HSI remained unchanged under LDB condition. The decrease in oxidative damage by LDB could be attributed to the up-regulated levels of mRNA, protein, and activity of Cu/Zn-SOD and CAT. A failure to activate the activity of both enzymes may result in the enhanced PC levels under LDR condition, though both genes were up-regulated at transcriptional and translational levels. In the ovary, although gonadosomatic index sharply increased under LDR condition, LPO and PC dramatically accumulated. The increase in oxidative damage by LDR might result from the down-regulated levels of protein and activity of Cu/Zn-SOD and CAT, though both genes were up-regulated at a transcriptional level. Furthermore, a sharp increase in expression of transcription factor Nrf2 that targets antioxidant genes was observed in the liver but not in the ovary under LDB and LDR conditions. In conclusion, our data demonstrated a positive effect of LDB and negative effect of LDR on fish antioxidant defenses, emphasizing the potentials of LDB as an effective light source in fish farming.

Organ-specific effects of low-dose zinc pre-exposure on high-dose zinc induced mitochondrial dysfunction in large yellow croaker Pseudosciaena crocea.

The study was carried out to evaluate the effects of low-dose zinc (Zn) pre-exposure on survival rate, new Zn accumulation, and mitochondrial bioenergetics in the liver and spleen of large yellow croaker exposed to high-dose Zn. To the end, fish were pre-exposed to 0 and 2 mg L-1 Zn for 48 h and post-exposed to 0 and 12 mg L-1 Zn for 48 h. Twelve milligrams Zn per liter exposure alone reduced survival rate, but the effect did not appear in the 2 mg L-1 Zn pre-exposure groups. Two milligrams per liter Zn pre-exposure also ameliorated 12 mg Zn L-1 induced new Zn accumulation, reactive oxygen species (ROS) levels, and mitochondrial swelling in the liver. However, these effects did not appear in the spleen. In the liver, 2 mg L-1 Zn pre-exposure apparently relieved 12 mg L-1 Zn induced down-regulation of activities of ATP synthase (F-ATPase), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH). The mRNA levels of these genes remained relatively stable in fish exposed to 12 mg L-1 Zn alone, but increased in fish exposed to 12 mg L-1 Zn with 2 mg L-1 Zn pre-treatment. In the spleen, 2 mg Zn L-1 pre-exposure did not mitigate the down-regulation of mRNA levels of genes and activities of relative enzymes induced by 12 mg L-1 Zn. In conclusion, our study demonstrated low-dose zinc pre-exposure ameliorated high-dose zinc induced mitochondrial dysfunction in the liver but not in the spleen of large yellow croaker, indicating an organ-specific effect.

Circadian time-dependent antioxidant and inflammatory responses to acute cadmium exposure in the brain of zebrafish.

Up to date, little information is available on effects of circadian rhythm on metal-induced toxicity in fish. In this study, zebrafish were acutely exposed to 0.97mgL-1 cadmium for 12h either at ZT0 (the light intensity began to reached maximum) or at ZT12 (light intensity began to reached minimum) to evaluate the temporal sensitivity of oxidative stress and inflammatory responses in the brain of zebrafish. Profiles of responses of some genes at mRNA, protein and activity levels were different between ZT0 and ZT12 in the normal water. Exposure to Cd induced contrary antioxidant responses and similar inflammatory responses between ZT0 and ZT12. However, the number of inflammatory genes which were up-regulated was significantly greater at ZT12 than at ZT0. And, the up-regulated inflammatory genes were more responsive at ZT12 than at ZT0. At ZT12, antioxidant genes were down-regulated at mRNA, protein and activity levels. Contrarily, antioxidant genes were not affected at mRNA levels but activated at the protein and/or activity levels at ZT0. Reactive oxygen species (ROS) sharply increased and remained relatively stable when fish were exposed to Cd at ZT12 and ZT0, respectively. Positive correlations between ROS levels and mRNA levels of nuclear transcription factor κB (NF-κB) and between mRNA levels of NF-κB and its target genes were observed, suggesting that ROS may play an essential role in regulating the magnitude of inflammatory responses. Taken together, oxidative stress and immunotoxicity in the brain were more serious when fish were exposed to Cd in the evening than in the morning, highlighting the importance of circadian rhythm in Cd-induced neurotoxicity in fish.

Acute exposure to waterborne cadmium induced oxidative stress and immunotoxicity in the brain, ovary and liver of zebrafish (Danio rerio).

Cadmium (Cd) is an environmental contaminant that poses serious risks to aquatic organisms and their associated ecosystem. The mechanisms underlying Cd-induced oxidative stress and immunotoxicity in fish remain largely unknown. In this study, adult female zebrafish were exposed to 0 (control), 1mgL-1 Cd for 24h and 96h, and the oxidative stress and inflammatory responses induced by Cd were evaluated in the brain, liver and ovary. Reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) increased in a time-dependent manner after treatment with Cd in the brain and liver. The increase may result from the disturbance of genes including copper and zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), inducible nitric oxide synthase (iNOS), and ciclooxigenase-2 (COX-2) at mRNA, protein and activity levels. Although ROS, NO and MDA were not significantly affected by Cd in the ovary, the up-regulation of Cu/Zn-SOD, CAT, iNOS, and COX-2 was observed. Exposure to Cd induced a sharp increase in the protein levels of tumor necrosis factor alpha (TNF-α) in the brain, liver and ovary, possibly contributing to activate inflammatory responses. Furthermore, we also found a dramatic increase in mRNA levels of NF-E2-related factor 2 (Nrf2) and nuclear transcription factor κB (NF-κB) at 24h in the liver and ovary. The corresponding changes in the mRNA levels of Kelch-like-ECH-associated protein 1 (Keap1a and Keap1b) and the inhibitor of κBα (IκBαa and IκBαb) may contribute to regulate the transcriptional activity of Nrf2 and NF-κB, respectively. Contrarily, mRNA levels of Nrf2, NF-κB, Keap1, Keap1b, IκBαa and IκBαb remained stable at 24 and 96h in the brain. Taken together, we demonstrated Cd-induced oxidative stress and immunotoxicity in fish, possibly through transcriptional regulation of Nrf2 and NF-κB and gene modifications at transcriptional, translational, post-translational levels, which would greatly extend our understanding on the Cd toxicity.

Positive and negative innate immune responses in zebrafish under light emitting diodes conditions.

Certain light emitting diodes (LEDs) have become popular in fish farming beacause of a promoting effect on growth and reproduction. However, little information is available on innate immune responses in related tissues under LEDs conditions. The present study assessed the effects of a white fluorescent bulb (the control) and two different light-emitting diodes (LEDs: blue, LDB, peak at 450 nm; red, LDR, 630 nm) on growth and innate immune responses in the serum, liver and ovary of zebrafish for 8 weeks. LDB significantly enhanced specific growth rate (SGR), food intake (FI), and serum globulin levels. In contrast, LDR sharply inhibited SGR, FI, and the levels of albumin and globulin. Under LDB condition, there was an increase in protein levels of alkaline phophatase (AKP) and protein and activity levels of lysozyme (LZM) in the liver, and the levels of mRNA, protein, and activity of LZM in the ovary. Under LDR condition, LZM was dramatically down-regulated at mRNA, protein and activity levels in the ovary, suggesting that LZM was regulated at a transcriptional level. In the liver of the LDR group, though AKP mRNA levels sharply increased, its protein and activity levels significantly declined, indicating that AKP was regulated at translational level. Furthermore, a positive correlation between transcription factor NF-κB RelA mRNA levels and expression levels of AKP and LZM was observed in the liver and ovary, implying a transcriptional regulation of NF-κB RelA. In conclusion, the present study demonstrated a positive effect of LDB and negative effect of LDR on fish growth and innate immune responses, possibly associated with modifications at transcriptional, translational, and post-translational levels, and the transcriptional regulation of the NF-κB signaling molecule.

Chronic waterborne zinc and cadmium exposures induced different responses towards oxidative stress in the liver of zebrafish.

Based on the same toxic level of 0.6% LC50 for 96-h and the severe situation of water pollution, we compared effects of chronic Zn (180µgL(-1)) and Cd exposures (30µgL(-1)) on growth, survival, histology, ultrastructure, and oxidative stress in the liver of zebrafish for 5 weeks. Growth performance and survival rate remained relatively constant under Zn stress, but was reduced under Cd exposure. Cd exposure also induced severe pyknotic nuclei, evident ultrastructure damage, and considerable lipid inclusions in the hepatocytes. However, these phenomena were not pronounced under Zn exposure. The negative effects caused by Cd may be explained by an increase in hepatic oxidative damage, as reflected by the enhanced levels of lipid peroxidation (LPO) and protein carbonylation (PC). The reduced activity of Cu/Zn-superoxide dismutase (Cu/Zn-SOD) and catalase (CAT) may result in the enhanced hepatic oxidative damage, though the mRNA and protein levels of both genes increased and remained unchanged respectively. On the contrary, Zn up-regulated the levels of mRNA, protein and activity of Cu/Zn-SOD, which may contribute to the decreased LPO levels. Nonetheless, the sharply up-regulated mRNA levels of CAT did not induce an increase in the protein and activity levels of CAT under Zn stress. Furthermore, transcription factor NF-E2-related factor 2 (Nrf2) expression parelleled with its target genes, suggesting that Nrf2 is required for the protracted induction of antioxidant genes. In conclusion, our data demonstrated that essential and non-essential metals induced some differences in oxidative damage in fish. The differences were not caused by the transcriptional level of related genes but depended on post-transcriptional modifications.

[Epidemiological characteristics and control status of hypertension in rural area of the Three Gorges].

OBJECTIVE: To evaluate the epidemiological features and control status of hypertension in rural area of The Three Gorges. METHODS: A cross-sectional survey was carried out in rural area of Yiling District, Yichang City, which was located north-west bank of Xiling Gorges in 2007. A standard structure questionnaire was used to collect data on the hypertension history and treatment, social-economic status and life-styles, and so on. Blood pressure was measured by trained observers using standardized mercury sphygmomanometer. Hypertension was defined as systolic blood pressure ≥ 140 mm Hg (1 mm Hg = 0.133 kPa) and/or diastolic ≥ 90 mm Hg, or current treatment with antihypertensive medications. Hypertension control was defined as blood pressure levels of less than 140/90 mm Hg. RESULTS: A total of 9618 residents aged 35 years and above were included (response rate: 81.3%), and 19.7% residents were the Three Gorges migrants. The age-adjusted prevalence of hypertension was 37.3% for all, and 21.3%, 39.8%, 58.0% for aged 35 - 44, 45 - 59, ≥ 60 years, respectively. The age-adjusted rate was higher in men for all (39.1%) and aged 35 - 44 years (27.0%) than in women (36.3% for all and 17.8% for aged 35 - 44 years, P < 0.01). The age-adjusted rate of awareness, treatment and control rates of hypertension were lower in men (18.5%, 9.0%, 0.9%, respectively) than in women (23.5%, 13.6%, 2.0%, respectively, all P < 0.01). Among the participants with treated hypertension, the control rate of hypertension was only 17.0%. Prevalence and rate of awareness, treatment and control of hypertension were similar between migrants and non-migrants. CONCLUSION: The prevalence of hypertension is high, but the awareness, treatment, control rates were low in rural area of Yiling District. Efforts should be made to reduce the prevalence rate and to improve the control rate of hypertension in this area.