油菜素内酯对亚适宜温光盐环境下黄瓜幼苗根系生长及其AsA-GSH循环的影响

以‘津春2号’黄瓜幼苗为试材,研究了24-表油菜素内酯(EBR)对亚适宜温光盐环境下黄瓜幼苗根系生长及其抗坏血酸-谷胱甘肽(As A-GSH)循环系统的影响。结果表明:亚适宜温光盐环境导致黄瓜幼苗根系的超氧阴离子(O2-·)产生速率及过氧化氢(H2O2)、丙二醛(MDA)含量增加,膜脂过氧化程度加剧,幼苗根系生长显著受抑;EBR能通过提高亚适宜温光盐环境下黄瓜幼苗根系的抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、脱氢抗坏血酸还原酶(DHAR)等抗氧化酶比活性、抗氧化剂(As A、GSH)含量以及还原型谷胱甘肽与氧化型谷胱甘肽含量比值(GSH/GSSH)和还原型抗坏血酸与氧化型抗坏血酸比值(As A/DHA),促进亚适宜温光盐环境下黄瓜幼苗根系体内As A-GSH循环运转,维持较强的抗氧化性能,显著降低了O2-·产生速率及H2O2、MDA含量,减少膜脂过氧化程度,从而促进了亚适宜温光盐环境下黄瓜幼苗根系的生长。     

Effect of aeration strategy on the metabolic flux of <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> producing 1,3-propanediol in continuous cultures at different glycerol concentrations

The microbial production of 1,3-propaneidol (1,3-PD) by Klebsiella pneumoniae in continuous fermentation was investigated under low, medium and high glycerol concentrations in the absence and presence of oxygen. The production of 1,3-PD increased with increasing glycerol concentrations, reaching a maximum (266 mmol l⁻¹) under high glycerol concentration (760 mmol l⁻¹) with air sparging at 0.04 vvm. The yield of 1,3-PD, however, decreased gradually with increasing glycerol concentrations, with the highest yield (0.52 mol mol⁻¹) obtained for low glycerol concentration (270 mmol l⁻¹) under anaerobic condition. Enzyme activity assays showed that the specific activity of glycerol dehydratase was highest (0.04 U mg⁻¹) for culture sparged with 0.04 vvm air under high glycerol concentration. The specific activities of glycerol dehydrogenase and 1,3-propanediol oxidoreductase were also improved for all glycerol concentrations and in the presence of oxygen, implying that the dha operon was not repressed under microaerobic conditions. Analysis of metabolic fluxes showed that more carbon flux was shifted to the oxidative pathway with increasing glycerol concentrations, resulting in a reduced flux to 1,3-PD formation. However, the increases in carbon fluxes were not evenly distributed among the oxidative branches of the pathway. Furthermore, ethanol and acetic acid levels were slightly increased whereas 2,3-butanediol and lactic levels were greatly enhanced.     

云南普洱市野生果类植物资源研究

初步查明普洱市常见的野生果类植物有59种,隶属于25科37属。对部分特色野果作了叙述,并阐述了野生果类植物开发利用的现状,提出了合理开发利用野生果类植物资源的建议。     

Diluted seawater promoted the green tide of Ulva prolifera (Chlorophyta,Ulvales)

Ulva prolifera (Müller) J. Agardh is the main causative species of the 2008 Yellow Sea green tide incident. We investigated the influences of diluted seawater on the vegetative growth and reproductive cell formation of the alga. The thalli that were cultivated under low salinities (10‰ and 20‰) and low pH values (pH around 7.0) showed obvious and steady biomass gain, while those cultivated under high salinities (40‰) and relatively higher pH conditions (pH around 8.0) manifested significant biomass loss. The trend was, however, completely the opposite for reproductive cell formation and there were indications that enrichment, over very wide concentration ranges of both nitrogen and phosphate, could significantly promote vegetative growth. Results also indicated that relatively low salinity and low pH regimes boosted vegetative growth but were unfavorable for reproductive cell formation and vice versa. Based on these results, the possible origin and development mechanisms of the green tide event are discussed. Eutrophication in the Changjiang River estuary and adjacent sea areas, as well as extremely high freshwater inflows before, and during, the flood of 2007 – due to the full operation of large‐scale water facilities in the area – may have both played an important role in the formation and development of the green tide event.     

Cardiomyocyte-specific disruption of Serca2 in adult mice causes sarco(endo)plasmic reticulum stress and apoptosis

Reduced sarco(endo)plasmic reticulum (SR) Ca(2+) ATPase (SERCA2) contributes to the impaired cardiomyocyte Ca(2+) homeostasis observed in heart failure. We hypothesized that a reduction in SERCA2 also elicits myocardial ER/SR stress responses, including unfolded protein responses (UPR) and cardiomyocyte apoptosis, which may additionally contribute to the pathophysiology of this condition. Left ventricular myocardium from mice with cardiomyocyte-specific tamoxifen-inducible disruption of Serca2 (SERCA2 KO) was compared with aged-matched controls. In SERCA2 KO hearts, SERCA2 protein levels were markedly reduced to 2% of control values at 7 weeks following tamoxifen treatment. Serca2 disruption caused increased abundance of the ER stress-associated proteins CRT, GRP78, PERK, and eIF2α and increased phosphorylation of PERK and eIF2α, indicating UPR induction. Pro-apoptotic signaling was also activated in SERCA2 KO, as the abundance of CHOP, caspase 12, and Bax was increased. Indeed, TUNEL staining revealed an increased fraction of cardiomyocytes undergoing apoptosis in SERCA2 KO. ER-Tracker staining additionally revealed altered ER structure. These findings indicate that reduction in SERCA2 protein abundance is associated with marked ER/SR stress in cardiomyocytes, which induces UPR, apoptosis, and ER/SR structural alterations. This suggests that reduced SERCA2 abundance or function may contribute to the phenotype of heart failure also through induction of ER/SR stress responses.     

Time-dependent density functional theory study of the excited-state dihydrogen bonding: clusters of 2-pyridone with diethylmethylsilane and triethylgermanium

Density functional theory (DFT) was carried out to identify the existence of intermolecular dihydrogen bonds of the 2-pyridone (2PY)-diethylmethylsilane (DEMS) and 2PY-triethylgermanium (TEGH) clusters in the ground state. The H···H distances of both clusters are shorter than the sum of their van der Waals radii. Thus, intermolecular dihydrogen bonds N–H•••H–Si and N–H•••H–Ge exist in the 2PY-DEMS and 2PY-TEGH clusters, respectively. Based on the ground-state conformations, intermolecular dihydrogen bonds N–H•••H–Si and N–H•••H–Ge in the electronically excited state of the 2PY-DEMS and 2PY-TEGH clusters were also investigated using time-dependent density functional theory (TDDFT). Electronic transition of the 2PY-DEMS cluster resembles that of the 2PY-TEGH cluster. Their S₁ state is a locally excited (LE) state centered on 2PY moiety. The H•••H distances of the 2PY-DEMS and 2PY-TEGH clusters both stretch in the S₁ state compared to those in the ground state. Upon electronic excitation, intermolecular dihydrogen bonding N–H•••H–Si and N–H•••H–Ge can weaken with decreasing dihydrogen bonding energies.     

Cognitive and serum BDNF correlates of BDNF Val66Met gene polymorphism in patients with schizophrenia and normal controls

Studies suggest that a functional polymorphism of the brain-derived neurotrophic factor gene (BDNF Val66Met) may mediate hippocampal-dependent cognitive functions. A few studies have reported its role in cognitive deficits in schizophrenia including its association with peripheral BDNF levels as a mediator of these cognitive deficits. We assessed 657 schizophrenic inpatients and 445 healthy controls on the repeatable battery for the assessment of neuropsychological status (RBANS), the presence of the BDNF Val66Met polymorphism and serum BDNF levels. We assessed patient psychopathology using the Positive and Negative Syndrome Scale. We showed that visuospatial/constructional abilities significantly differed by genotype but not genotype?×?diagnosis, and the Val allele was associated with better visuospatial/constructional performance in both schizophrenic patients and healthy controls. Attention performance showed a significant genotype by diagnosis effect. Met allele-associated attention impairment was specific to schizophrenic patients and not shown in healthy controls. In the patient group, partial correlation analysis showed a significant positive correlation between serum BDNF and the RBANS total score. Furthermore, the RBANS total score showed a statistically significant BDNF level?×?genotype interaction. We demonstrated an association between the BDNF Met variant and poor visuospatial/constructional performance. Furthermore, the BDNF Met variant may be specific to attentional decrements in schizophrenic patients. The association between decreased BDNF serum levels and cognitive impairment in schizophrenia is dependent on the BDNF Val66Met polymorphism.