中性内肽酶及其抑制剂在心血管疾病过程中的作用

中性内肽酶是一种属于Ⅱ型跨膜蛋白的肽类内切酶,在肽链的氨基端水解疏水氨基酸肽键,灭活心钠素、肾上腺髓质素、血管紧张素、内皮素等心血管活性肽,在高血压病、心力衰竭、动脉粥样硬化和休克等心血管疾病的发病过程中发挥重要作用。     

Prediction of tyrosine sulfation with mRMR feature selection and analysis

Protein tyrosine sulfation is a ubiquitous post-translational modification (PTM) of secreted and transmembrane proteins that pass through the Golgi apparatus. In this study, we developed a new method for protein tyrosine sulfation prediction based on a nearest neighbor algorithm with the maximum relevance minimum redundancy (mRMR) method followed by incremental feature selection (IFS). We incorporated features of sequence conservation, residual disorder, and amino acid factor, 229 features in total, to predict tyrosine sulfation sites. From these 229 features, 145 features were selected and deemed as the optimized features for the prediction. The prediction model achieved a prediction accuracy of 90.01% using the optimal 145-feature set. Feature analysis showed that conservation, disorder, and physicochemical/biochemical properties of amino acids all contributed to the sulfation process. Site-specific feature analysis showed that the features derived from its surrounding sites contributed profoundly to sulfation site determination in addition to features derived from the sulfation site itself. The detailed feature analysis in this paper might help understand more of the sulfation mechanism and guide the related experimental validation.     

高粱泡的生长调控与结实状况

高粱泡(Rubus lambertionus Ser.)是一种有利用价值的野生果树资源。其优点为:(1)结果早,产量高,亩产量可达500kg以上;(2)适应性广,耐瘠薄,是开发利用低山丘陵的优良资源植物;(3)果实营养丰富,酸味纯正,尤其是所含红色素稳定性好,是加工果汁饮料的优质添加剂;(4)果实采收期在11月中旬到12月底,此时气温低,有利于浆果加工和贮藏,并可利用农闲季节的劳动力。上述特点表明,高粱泡有很好的开发利用前景。但本种在野生状态下蔓生性强,多刺,并具有枝顶生根的习性,因而树形紊乱而松散,栽培时搭架困难,植株占地面积大,而单位面积产量不易提高。为了便于操作管理和提高产量,减少栽培成本,增进经济效益,我们于1990～1991年进行了生长和株形调控试验,     

Composition and variability of biofouling organisms in seawater reverse osmosis desalination plants

Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Cellulophaga based on 16S rRNA gene sequencing analysis. The 16S rRNA gene clone library of the SWRO membrane biofilm showed that a filamentous bacterium, Leucothrix mucor, which belongs to the gammaproteobacteria, accounted for nearly 30% of the clone library, while the rest of the microorganisms (61.2% of the total clones) were related to the alphaproteobacteria. 16S rRNA gene terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that bacteria colonizing the SWRO membrane represented a subportion of microbes in the source seawater; however, they were quite different from those colonizing the cartridge filter. The examination of five SWRO membranes from desalination plants located in different parts of the world showed that although the bacterial communities from the membranes were not identical to each other, some dominant bacteria were commonly observed. In contrast, bacterial communities in source seawater were significantly different based on location and season. Microbial profiles from 14 cartridge filters collected from different plants also revealed spatial trends.     

Novel nonapeptide GLP (28–36) amide derivatives with improved hypoglycemic and body weight lowering effects

Glucagon-like peptide-1 (GLP-1) has emerged as a major therapeutic target for the treatment of type 2 diabetes. The nonapeptide GLP-1 (28–36) amide is one of the biological C-terminal products of GLP-1 modified by the neutral endopeptidase (NEP) 24.11 with limited hypoglycemic activity. In this study, we focused on the modification of GLP-1 (28–36) amide for the first time and synthesized a series of GLP-1 (28–36) amide analogues. Results of biological activity evaluation in INS-1 cell, STZ-induced diabetic and diet induced obesity (DIO) mice indicated that S3 as a promising candidate to treat type 2 diabetes and obesity.     

p38丝裂素活化蛋白激酶介导低氧预处理诱导的内质网应激相关的心肌细胞保护

钙网蛋白（calreticulin,CRT）和caspase-12是重要的内质网（endoplasmic reticulum,ER）应激分子,本实验在心肌细胞低氧／复氧（hypoxia／reoxygenation,H／R）模型上观察低氧预处理（hypoxic preconditioning,HPC）对CRT和caspase-12表达及活化的影响,探讨内质网应激（endoplasmic reticulum stress,ERS）在HPC保护机制中的意义及其细胞信号转导机制。原代培养的Sprague-Dawley乳鼠心肌细胞随机分为6组：H／R组、HPC＋H／R组、SB203580＋HPC＋H／R组、SP600125＋HPC＋H／R组、HPC组和对照组。以细胞存活率、乳酸脱氢酶（lactate dehydrogenase,LDH）活性及流式细胞术检测细胞损伤情况：Western blot方法检测CRT和caspase-12表达、活化及p38丝裂素活化蛋白激酶（mitogen—activated protein kinases,MAPK）、cJun N-terminal kinase（JNK）磷酸化水平。结果表明：（1）HPC具有细胞保护作用,与H／R组比较,HPC＋H／R组细胞凋亡率和LDH漏出分别降低6．6％和70．0％,存活率增高6．4％：HPC前以特异性p38MAPK抑制剂SB203580预孵育消除HPC的保护作用,与HPC＋H／R组相比,细胞凋亡率和LDH漏出分别增高5．4％和2．1倍,存活率降低5．4％,JNK特异性抑制剂SP600125预孵育对HPC的保护作用无明显影响。（2）H／R明显上调CRT表达（较对照组高8．1倍）和caspase-12活性（较对照组高33．2倍）;单独HPC可诱导CRT表达增多（较对照组高2．6倍）,但上调程度较H／R组低60％。H／R前进行HPC降低CRT过表达程度（降低72．4％）及caspase-12活化水平（降低59．6％）。（3）HPC前应用p38MAPK抑制剂,抑制CRT表达上调（分别较HPC＋H／R组和HPC组低63．9％和71．9％）,并消除HPC减轻H／R上调caspase-12活性的作用（较HPC＋H／R组高7．1倍）;HPC前抑制JNK活性对CRT、caspase-12表达和活化均无明显影响。上述结果提示：HPC可激发适当的ERS,抑制H／R诱导的过度ERS,减少ER凋亡信号介导的细胞凋亡。p38MAPK信号途径在HPC诱导的ER应激分子表达、抑制ER凋亡信号分子活化等机制中发挥重要作用。     

An unusual Group 2 LEA gene family in citrus responsive to low temperature

Six cDNAs representing unique cold-induced sequences have been cloned from the hardy citrus relative Poncirus trifoliata. Among these, pBCORc115 and pBCORc119 were found to belong to the same gene family. Sequencing data indicated that pBCORc115 and pBCORc119 each contained an open reading frame, coding for a 19.8 kDa protein (COR19) and a smaller 11.4 kDa protein (COR11) respectively. Inspection of the deduced amino acid sequences revealed three large repeats in COR19, but only one was present in the COR11. Two elements: a Q-clustered tract and a K-rich motif were identified in each repeat. The K-rich motifs were similar to those of cotton D-11 and Group 2 LEA proteins. A Serine-cluster, a common feature in many Group 2 LEA-like proteins, was also found in these proteins, but it was in an unusual position at the carboxy-terminus. A bipartite motif of basic residues, similar to known nuclear targeting sequences, was also present in COR19 and COR11, suggesting that members of this protein family may have a nuclear targeting function. The expression of COR19 mRNA in response to cold acclimation, drought, flooding, and salinization was examined. COR19 expression in leaf tissue was induced in response to cold acclimation, but repressed during drought and flooding stress.     

Synergistic effect of colonization with arbuscular mycorrhizal fungi improves growth and drought tolerance of Plukenetia volubilis seedlings

The objective of this study was to investigate the effects of arbuscular mycorrhizal fungus (AMF) inoculation on plant growth and drought tolerance in seedlings of a promising oilseed crop, Sacha Inchi (Plukenetia volubilis L.), under well-watered or drought conditions. AMF inoculation was applied in four treatments: without AMF inoculation, Glomus versiforme, Paraglomus occultum, or combination of both microorganism inoculations. The results showed that AMF colonization significantly enhanced the growth of Sacha Inchi seedlings regardless of soil water conditions, and the greatest development was reached in plants dually inoculated under well-watered conditions. G. versiforme was more efficient than P. occultum. Plants inoculated with both symbionts had significantly greater specific leaf area, leaf area ratio and root volume when compared with the uninoculated control, G. versiforme, and P. occultum treatments alone, indicating a synergistic effect in the two AMF inoculation. Photosynthetic rate and water-use efficiency were stimulated by AMF, but not stomatal conductance. Inoculation with AM fungus increased antioxidant enzymes activities including guaiacol peroxidase and catalase, thus lowering hydrogen peroxide accumulation and oxidative damage, especially under drought stress conditions. However, proline content showed little change during drought stress and AMF colonization conditions, which suggested that proline accumulation might not serve as the main compound for osmotic adjustment of the studied species. These results indicate that AMF inoculation stimulated growth and enhanced drought tolerance of Sacha Inchi seedlings, through alterations in morphological, physiological and biochemical traits. This microbial symbiosis might be an effective cultivation practice in improving the performance and development for Sacha Inchi plants.