家蚕血液过氧化氢酶活力及其与蚕体抗逆性的关系

家蚕召Bombyx mori(L.)血液过氧化氢酶(CAT)活力随发育时期呈现有规律的动态变化。在幼虫期,CAT活力以龄初、龄末较高,而龄中较低;化蛹后,CAT活力迅速上升,至中期达到峰值,随后迅速下降直至羽化。不同性别间CAT活力均以雄性较高;不同蚕品种间CAT活力有很大差异;饲料对CAT活力有一定影响,人工饲料育蚕CAT活力略大于桑叶育的;高温冲击和氟化物添食都能引起CAT活力的显著变化,但变化的幅度因品种、性别、时期和添食剂量而有所不同。研究认为,家蚕血液CAT活力与其发育变态、体内代谢均具有密切关系,逆境条件下CAT活力变化幅度的大小可以作为家蚕抗逆性强弱的一个重要生理指标。     

Impacts of fish aggregation devices on size structures of skipjack tuna Katsuwonus pelamis

Tuna purse seine fisheries target fish aggregated in schools, including free schools that are formed naturally based on fish biology and aggregations associated with natural and/or artificial drifting objects. Using data collected from skipjack tuna (Katsuwonus pelamis) fisheries, we evaluated differences in size structures between drifting-floating-object-associated schools and unassociated schools. We developed a generalized linear model to remove impacts of environmental variables on skipjack size composition. This study indicates that the drifting-floating-object-associated schools tended to have significantly wider size ranges than the unassociated schools. This suggests that unassociated schools were likely formed based on similarity in sizes among individuals within a school while drifting-floating-object-associated schools were probably composed of individuals of large size ranges and their formation was not based on the “size selection” rule. We concluded that the unassociated schools and the drifting-floating-object-associated schools were formed through different mechanisms, and drifting floating objects could aggregate unassociated schools of different size structures. Thus, a large scale of deployment of man-made floating objects might disrupt the spatial aggregation pattern of fish that otherwise tended to school based on their sizes in the absence of floating objects.     

耕作措施对土壤水热特性和微生物生物量碳的影响

通过山西寿阳设置的8a田间定位试验,比较了全量秸秆还田、免耕覆盖和常规耕作3种耕作措施下土壤含水量、温度及土壤微生物生物量碳变化.结果表明:免耕覆盖与全量还田处理显著提高土壤含水量,与常规耕作相比表层土壤体积含水量在玉米苗期、拔节期、灌浆期和成熟期分别高出18％、22％、29％、21％和3％、10％、12％、13％,具有保水保墒的作用.在苗期不同耕作措施对土壤温度的影响达到显著水平,5 cm处免耕覆盖、全量还田与常规耕作处理土壤温度依次为:18.12、18.76和19.44℃,免耕覆盖和全量还田处理平均温度比常规耕作分别低1.32℃和0.69℃.土壤微生物量碳在整个生育期动态变化是首先迅速上升在玉米生育高峰期(拔节期)达到最高峰,然后开始下降,成熟期趋于平缓.免耕覆盖与全量还田处理下玉米各生育期土壤表层微生物量碳显著高于常规耕作,在苗期、拔节期、灌浆期和成熟期分别比常规耕作高出70％、40％、85％和30％和10％、20％、15％和15％.土壤微生物量碳与土壤温度和土壤含水量相关和极相关.     

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.     

In-depth Profiling and Quantification of the Lysine Acetylome in Hepatocellular Carcinoma with a Trapped Ion Mobility Mass Spectrometer

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death worldwide with limited therapeutic options. Comprehensive investigation of protein posttranslational modifications in HCC is still limited. Lysine acetylation is one of the most common types of posttranslational modification involved in many cellular processes and plays crucial roles in the regulation of cancer. In this study, we analyzed the proteome and K-acetylome in eight pairs of HCC tumors and normal adjacent tissues using a timsTOF Pro instrument. As a result, we identified 9219 K-acetylation sites in 2625 proteins, of which 1003 sites exhibited differential acetylation levels between tumors and normal adjacent tissues. Interestingly, many novel tumor-specific K-acetylation sites were characterized, for example, filamin A (K865), filamin B (K697), and cofilin (K19), suggesting altered activities of these cytoskeleton-modulating molecules, which may contribute to tumor metastasis. In addition, we observed an overall suppression of protein K-acetylation in HCC tumors, especially for enzymes from various metabolic pathways, for example, glycolysis, tricarboxylic acid cycle, and fatty acid metabolism. Moreover, the expression of deacetylase sirtuin 2 (SIRT2) was upregulated in HCC tumors, and its role of deacetylation in HCC cells was further explored by examining the impact of SIRT2 overexpression on the proteome and K-acetylome in Huh7 HCC cells. SIRT2 overexpression reduced K-acetylation of proteins involved in a wide range of cellular processes, including energy metabolism. Furthermore, cellular assays showed that overexpression of SIRT2 in HCC cells inhibited both glycolysis and oxidative phosphorylation. Taken together, our findings provide valuable information to better understand the roles of K-acetylation in HCC and to treat this disease by correcting the aberrant acetylation patterns.     

Characterization of the androgen-dependent 22Kdalton glycoprotein from rat ventral prostate

Oxidation by molecular oxygen converted the 22Kdalton glycoprotein from rat ventral prostate into a 34K species and this reaction could be reversed by thiol reducing reagent. Measurement of the level of the 22Kdalton glycoprotein in prostatic cytosol by the radial immunodiffusion technique showed that changes in the 22Kdalton glycoprotein concentration in response to androgen withdrawal and replacement were slow in comparison to androgen regulated levels of mRNA coding for the protein. (3) Charcoal absorption steroid binding assays of the 22Kdalton glycoprotein revealed that the protein did not bind testosterone, estradiol, progesterone or corticosterone. These results indicate that the 22Kdalton glycoprotein is metabolically stable, not steroid-binding, and exists as an oligomer through disulfide crosslinking.     

湖南沅江鼎城段河蚬的性别组成与精子形态特征

本研究以湖南沅江鼎城段河蚬(Corbicula fluminea)为研究对象,在进一步验证该群体性别组成的基础上,分析壳长组成与性别比例之间关系,探讨该群体雄性、雌性和雌雄同体之间关系;同时以单鞭毛精子为参照,分析比较双鞭毛精子的形态特征,以期为我国河蚬的性别发生及生殖适应策略研究提供基础资料。结果显示：沅江鼎城段河蚬(n = 770)雄性、雌性和雌雄同体最小性成熟壳长分别为2.92 mm、5.66 mm和5.30 mm。697只性成熟河蚬中雄性、雌性和雌雄同体的比例近似1︰1︰6。雌雄同体的平均壳长[(22.55 ± 0.33)mm,n = 517]显著大于雄性[(20.44 ± 1.03)mm,n = 95]和雌性[(19.79 ± 0.99)mm,n = 85](P < 0.05),但雄性与雌性的平均壳长之间差异不显著(P > 0.05)。河蚬可以产生单鞭毛和双鞭毛两种类型的精子,单鞭毛精子头长范围4.93 ~ 21.79 μm,平均值(14.27 ± 0.82)μm(n = 30),双鞭毛精子头长范围10.29 ~ 22.04 μm,平均值(15.62 ± 0.62)μm(n = 26)。单、双鞭毛精子头长差异不显著(P > 0.05)。双鞭毛精子(n = 26)长尾的平均长度[(38.07 ± 1.44)μm]显著大于其短尾[(31.08 ± 1.60)μm]和单鞭毛精子(n = 30)尾部长度[(30.15 ± 1.75)μm](P < 0.01),但其短尾与单鞭毛精子的尾部平均长度之间无显著性差异(P > 0.05)。结果表明：湖南沅江鼎城段河蚬为雄性先熟,且可能存在雄性和(或)雌性向雌雄同体转换现象。河蚬具有单鞭毛型和双鞭毛型2种类型的精子,且双鞭毛精子的2个尾部不等长。同域共存河蚬的单鞭毛与双鞭毛精子在运动及受精能力方面的差异值得深入研究。     

Modification of alternative splicing in bovine somatic cell nuclear transfer embryos using engineered CRISPR-Cas13d

Animal cloning can be achieved by somatic cell nuclear transfer(SCNT), but the resulting live birth rate is relatively low. We previously improved the efficiency of bovine SCNT by exogenous melatonin treatment or by overexpression of lysine-specific demethylase 4D(KDM4D) and 4E(KDM4E). In this study, we revealed abundant alternative splicing(AS) transitions during fertilization and embryonic genome activation, and demonstrated abnormal AS in bovine SCNT embryos compared with in vitro fertilized ...     

供氮水平对盐胁迫下水稻叶片光合及叶绿素荧光特性的影响

为了解供氮水平对不同时期盐胁迫下水稻(Oryza sativa)叶片光合及叶绿素荧光特性的影响, 以2个北方常规粳稻(Oryza sativa subsp. japonica)品种为材料, 在5个氮水平下进行培养, 于分蘖期、孕穗期和抽穗期分别进行盐胁迫处理, 测定分析了水稻叶片光合及叶绿素荧光参数的变化。结果表明, 与对照相比, 盐胁迫下水稻叶片的净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)和表观叶肉导度(AMC)均显著降低, 在分蘖期、孕穗期和抽穗期分别以2N、1N和1/2N水平下降低的百分率最小; 气孔限制值(L_s)则显著增加, 分别以2N、1N和1/2N水平下增加的百分率最大。盐胁迫下, 与对照相比, PSII的实际光合效率(ΦPSII)、表观光合量子传递效率(ETR)和光化学淬灭(qP)均显著降低, 在分蘖期、孕穗期和抽穗期分别以2N、1N和1/2N水平下降低的百分率最小; 非光化学淬灭(NPQ)呈增加的变化趋势, 与对照相比, 分别以2N、1N和1/2N水平下增加的百分率最小。以上结果说明盐胁迫下水稻孕穗后, 供氮水平适量降低有利于减缓叶片光合作用的下降, 提高其抵御盐害能力。