A Cysteine Endopeptidase (“Dionain”) Is Involved in the Digestive Fluid of Dionaea muscipula (Venus’s Fly-trap)

The carnivorous plant Dionaea muscipula (Venus’s flytrap) secretes proteinases into the digestive fluid to digest prey proteins. In this study, we obtained evidence that the digestive fluid contains a cysteine endopeptidase, presumably belonging to the papain family, through inhibitor studies and partial amino acid sequencing of the major SDS–PAGE band protein. The name “dionain” is proposed for the enzyme.     

人粒细胞集落刺激因子（hG－CSF）cDNA3′－UTR对其表达的影响

利用人粒细胞集落刺激因子（ｈＧ－ＣＳＦ）ｃＤＮＡ３′端非翻译区（３′－ＵＴＲ）中存在的ＤｒａⅠ酶切位点,通过部分酶切与完全酶切,删除３′－ＵＴＲ不同长度,构建了四种ｈＧ－ＣＳＦｃＤＮＡ瞬时重组表达质粒。转染ＣＯＳ－７细胞后,生物活性测定结果提示,ｈＧ－ＣＳＦｃＤＮＡ３′－ＵＴＲ对其表达起负调控作用,其关键性序列位于紧接终止密码子ＴＧＡ下游的６５ｂｐ范围内,３′－ＵＴＲ对ｈＧ－ＣＳＦｃＤＮＡ表达的影响与转录水平的差别有一定关系。     

Factors underpinning Iranian farmers’ intention to conserve biodiversity at the farm level

The depletion of biodiversity is a major environmental challenge of the present time, with the agricultural sector being a significant contributor to the loss. Therefore, farmers' decisions and practices are pivotal in safeguarding biodiversity at the farm level. Accordingly, this study aimed to unravel the key factors influencing farmers' intention to conserve biodiversity (ICB), and in doing so, it adopted the protection motivation theory (PMT) as the theoretical framework. The study's statistical population comprised 412 farmers residing in Bavi County in the southwestern region of Iran. The research employed a questionnaire as the data collection instrument, and the research hypotheses were tested using structural equation modeling (SEM). The findings indicated that the respondents held a perception of high costs associated with implementing biodiversity conservation behaviors. They believed that such measures would not be easy to implement, and they would incur both monetary and non-monetary costs. Furthermore, the findings of the study revealed that the variables of SE and ICB among the studied farmers were lower than the theoretical median of 3, indicating that farmers may not have a strong desire and self-efficacy to engage in biodiversity conservation practices. Through the application of SEM, the study determined that the PMT accounts for 65.2% of farmers’ ICB. Additionally, perceived severity and self-efficacy were found to have the strongest effects on farmers’ ICB (as the first and second determinants), highlighting the importance of these variables in predicting farmers’ conservation behaviors. Overall, it can be concluded that these results have significant implications for policymakers in the agricultural sector, providing valuable insights into how to promote biodiversity conservation practices among farmers.     

Simulation of grana stacking in a model membrane system. Mediation by a purified light-harvesting pigment-protein complex from chloroplasts

An isolated light-harvesting pigment-protein complex contains polypeptides which bind chlorophyll a and b. The individual complexes can be purified from detergent-solubilized membranes. The isolated light-harvesting complex, when dialyzed to remove detergents, was examined by freeze-fracture electron microscopy. The material consisted of planar sheets of 80-Å subunits which interacted via an edge-to-edge contact. Addition of cations caused the planar light-harvesting complex sheets to become tightly appressed in multilamellar stacks, with distinct subunits still visible within each lamellar sheet. A transition of particle organization from random to crystalline occurred in parallel with the cation-induced lamellar association. Treatment of the dialyzed light-harvesting complex subunits with low levels of the proteolytic enzyme trypsin removed a 2000 molecular weight segment of the major polypeptide of the light-harvesting complex and blocked all subsequent cation-induced changes in structural organization of the isolated light-harvesting complex lamellar sheets.To gain further evidence for mechanisms of cation effects upon the organization of the light-harvesting complex in native membranes, the light-harvesting complex was incorporated into uncharged (phosphatidylcholine) lipid vesicles. The protein complexes spanned the lipid bilayer and were arranged in either a random pattern or in hexagonal crystalline lattices. Addition of either monovalent or divalent cations to ‘low-salt’ (20 mM monovalent cation) vesicles containing light-harvesting complex caused extensive regions of membrane appression to appear. It is concluded that this cation-induced membrane appression is mediated by surface-exposed segments of the light-harvesting complex since (a) phosphatidylcholine vesicles themselves did not undergo cation-induced aggregation, and (b) mild trypsin digestion of the surface-exposed regions of the light-harvesting complex blocked cation-induced lamellar appression. The particles in the appressed vesicle membranes tended to form long, linear arrays of particles, with occasional mixed quasi-crystalline arrays with an angular displacement near 72°. Surface-mediated interactions among light-harvesting complex subunits of different membranes are, therefore, related to changes in structural organization and interaction of the particles within the lipid phase of the membrane.Numerous previous studies have implicated the involvement of the light-harvesting complex in mediating grana stocking in intact chloroplast membranes. The data presented herein provide a simulation of the membrane appression phenomena using a single class of chloroplast-derived membrane subunits. The data demonstrate that specific surface-localized regions of the light-harvesting complex are involved in membrane-membrane interactions.     

Free radicals impair the anti-oxidative stress activity of DJ-1 through the formation of SDS-resistant dimer

DJ-1 is a causative gene for familial Parkinson’s disease (PD). Loss-of-function of DJ-1 protein is suggested to contribute to the onset of PD, but the causes of DJ-1 dysfunction remain insufficiently elucidated. In this study, we found that the SDS-resistant irreversible dimer of DJ-1 protein was formed in human dopaminergic neuroblastoma SH-SY5Y cells when the cells were exposed to massive superoxide inducers such as paraquat and diquat. The dimer was also formed in vitro by superoxide in PQ redox cycling system and hydroxyl radical produced in Fenton reaction. We, thus, found a novel phenomenon that free radicals directly affect DJ-1 to form SDS-resistant dimers. Moreover, the formation of the SDS-resistant dimer impaired anti-oxidative stress activity of DJ-1 both in cell viability assay and H₂O₂-elimination assay in vitro. Similar SDS-resistant dimers were steadily formed with several mutants of DJ-1 found in familial PD patients. These findings suggest that DJ-1 is impaired due to the formation of SDS-resistant dimer when the protein is directly attacked by free radicals yielded by external and internal stresses and that the DJ-1 impairment is one of the causes of sporadic PD.     

野生瓣化型雄性不育胡萝卜‘武野-不育’的特征鉴定与分析

胡萝卜雄性不育材料,在胡萝卜育种中具有重要作用。本研究描述了一种从武汉市洪山区野生胡萝卜材料中获得的野生瓣化型胡萝卜雄性不育材料(‘武野-不育’,简称‘Wuye-BY’)的特征。该野生瓣化型雄性不育胡萝卜特征在于:无明显膨大的肉质根,嫩茎、叶片及其叶柄深绿色,几乎无毛,无花瓣和花药。花萼数量8~10个,花丝数量为0~2个,染色体数目为2n=18。双悬果顶端及其花丝顶端具有大量的蜜液,能接受栽培胡萝卜花粉。杂交F1的根大小、根重,胡萝卜素、总糖和维生素C含量,具有明显优势。     

Quantitative Metaproteomics and Activity-based Protein Profiling of Patient Fecal Microbiome Identifies Host and Microbial Serine-type Endopeptidase Activity Associated With Ulcerative Colitis

The gut microbiota plays an important yet incompletely understood role in the induction and propagation of ulcerative colitis (UC). Organism-level efforts to identify UC-associated microbes have revealed the importance of community structure, but less is known about the molecular effectors of disease. We performed 16S rRNA gene sequencing in parallel with label-free data-dependent LC-MS/MS proteomics to characterize the stool microbiomes of healthy (n = 8) and UC (n = 10) patients. Comparisons of taxonomic composition between techniques revealed major differences in community structure partially attributable to the additional detection of host, fungal, viral, and food peptides by metaproteomics. Differential expression analysis of metaproteomic data identified 176 significantly enriched protein groups between healthy and UC patients. Gene ontology analysis revealed several enriched functions with serine-type endopeptidase activity overrepresented in UC patients. Using a biotinylated fluorophosphonate probe and streptavidin-based enrichment, we show that serine endopeptidases are active in patient fecal samples and that additional putative serine hydrolases are detectable by this approach compared with unenriched profiling. Finally, as metaproteomic databases expand, they are expected to asymptotically approach completeness. Using ComPIL and de novo peptide sequencing, we estimate the size of the probable peptide space unidentified (“dark peptidome”) by our large database approach to establish a rough benchmark for database sufficiency. Despite high variability inherent in patient samples, our analysis yielded a catalog of differentially enriched proteins between healthy and UC fecal proteomes. This catalog provides a clinically relevant jumping-off point for further molecular-level studies aimed at identifying the microbial underpinnings of UC.     

红肉蜜柚汁胞蛋白质双向电泳体系优化研究

为建立适合红肉蜜柚发育过程中汁胞蛋白质组学的研究体系,以着色初始时期的红肉蜜柚汁胞为试材,摸索最适合的蛋白质双向电泳体系参数。结果表明,酚提取法比TCA-丙酮法更适合于红肉蜜柚汁胞总蛋白质的提取,提取得率高,双向电泳图谱清晰。采取18 cm、线性pH 3～10 和18 cm、线性pH 4～7 相结合的分析策略,可获得更为完整的蛋白质组信息,其第一向等电聚焦最佳参数（总伏小时数）分别为30 000 Vhs和43 000 Vhs。