利用黑曲霉固态发酵啤酒糟生产饲料复合酶的研究

以啤酒糟为主要基质,利用黑曲霉固态发酵生产酸性蛋白酶、木聚糖酶和纤维素酶等多种饲料复合酶,研究了黑曲霉固态发酵培养基组成对复合酶酶活的影响,确定最优培养基配方为:啤酒糟75%,麸皮25%,硫酸铵1%,KH_2PO_4 0.2%,MnSO_4 0.1%、ZnSO_4 0.2%,料水比1:2。在适宜的发酵条件下,经30℃发酵5 d,烘干后得到的复合酶制剂中,具有多种酶活性(以干基计)。其中酸性蛋白酶活力3 800 U/g,木聚糖酶活力12 00 U/g和纤维素酶活力18 U/g。     

Transcriptome Profiles in the Spleen of the Chinese Giant Salamander (Andrias davidianus) Challenged with Citrobacter freundii

Russian Journal of Bioorganic Chemistry - The Chinese giant salamander (Andrias davidianus) is one of the most important ecological breeding species with distinct characteristics and is cultured in...     

基于景观生态学“源-汇”理论的市域尺度生态功能分区——以内蒙古通辽市为例

市域尺度的生态功能分区对于市域生态资源的有效保护和合理利用起着不可替代的指导作用。现阶段较为被动而静态的功能分区研究忽视了市域生态资源在城镇化发展中的剧烈变化。而景观生态学的"源-汇"概念和相关手段,将区域生态功能空间格局与不断变化的生态过程之间建立了联系,在生态功能分区科学理性的研究实践中运用前景广阔。运用景观生态学"源-汇"理论,以内蒙古通辽市为例,通过对于研究区域中"源"景观的划分,设定不同景观要素的阻力值,构建基于"源"动态特征的最小累计阻力模型,计算得出阻力面。并进一步通过寻找阻力面突变点来确定分区阈值,最终确定通辽市域尺度生态功能的5大分区,最后提出有针对性的分区管控措施与指引。研究将市域生态要素在城市化下的动态演变与生态安全格局进行有机关联并制定科学的分区策略,为市域生态空间的优化及管理提供了理论依据。     

2-吗啉乙磺酸(MES)对拟南芥幼苗生长的影响

本实验研究0.05% MES对野生型拟南芥生长的影响。结果表明,含有MES的培养基pH变化较小,其培养10 d的拟南芥幼苗干重、鲜重、叶绿素含量和含水量均高于对照组,而叶片PAL和POD活性却低于对照组,说明MES通过影响培养基的pH变化促进拟南芥生长。     

Targeted ubiquitination of CDT1 by the DDB1-CUL4A-ROC1 ligase in response to DNA damage

Cullins assemble a potentially large number of ubiquitin ligases by binding to the RING protein ROC1 to catalyse polyubiquitination, as well as binding to various specificity factors to recruit substrates. The Cul4A gene is amplified in human breast and liver cancers, and loss-of-function of Cul4 results in the accumulation of the replication licensing factor CDT1 in Caenorhabditis elegans embryos and ultraviolet (UV)-irradiated human cells. Here, we report that human UV-damaged DNA-binding protein DDB1 associates stoichiometrically with CUL4A in vivo, and binds to an amino-terminal region in CUL4A in a manner analogous to SKP1, SOCS and BTB binding to CUL1, CUL2 and CUL3, respectively. As with SKP1-CUL1, the DDB1-CUL4A association is negatively regulated by the cullin-associated and neddylation-dissociated protein, CAND1. Recombinant DDB1 and CDT1 bind directly to each other in vitro, and ectopically expressed DDB1 bridges CDT1 to CUL4A in vivo. Silencing DDB1 prevented UV-induced rapid CDT1 degradation in vivo and CUL4A-mediated CDT1 ubiquitination in vitro. We suggest that DDB1 targets CDT1 for ubiquitination by a CUL4A-dependent ubiquitin ligase, CDL4A(DDB1), in response to UV irradiation.     

Clinical significance of peritumoral lymphatic vessel density and lymphatic vessel invasion detected by D2-40 immunostaining in FIGO Ib1-IIa squamous cell cervical cancer

The clinical significance of lymphangiogenesis in cervical cancer remains controversial. Our aim was to investigate the correlation between lymphangiogenesis, lymphatic vessel invasion (LVI) and tumor metastasis, invasion and prognosis in squamous cell cervical cancer. Paraffin sections of 90 patients with FIGO (Fédération Internationale de Gynécologie et d'Obstétrique) Ib1-IIa squamous cell cervical cancer were stained for immunohistochemistry with a D2-40 monoclonal antibody against the carcinoembryonic antigen M2A. The lymphatic vessel density (LVD) and LVI were measured, and their relationship with the clinicopathological data was analyzed. D2-40-positive lymphatic vessels were found in 75 of the 90 patients (83.3 %). All D2-40-positive vessels were located in peritumoral areas. The mean±SD of the peritumoral LVD was 10.08±4.16. The positive rate of LVI was 32.0 % (24/75). The recurrence rate of patients with LVD >10 (62.1 %, 18/29) was significantly higher than that of patients with LVD ≤10 (34.8 %, 16/46, P = 0.021). The 5-year recurrence-free survival rate of patients with LVD >10 (41.0 %) was significantly lower than that of patients with LVD ≤10 (67.0 %, P = 0.045). Univariate analysis showed that the peritumoral LVD (≤10 vs >10) was correlated with LVI (absent vs present, P = 0.016). The peritumoral LVD and LVI showed no correlation with age, FIGO stage, tumor size, tumor grade, depth of invasion, or pelvic lymph node metastasis (all: P > 0.05). Peritumoral lymphangiogenesis was correlated with the recurrence and recurrence-free survival in patients with squamous cell cervical cancer. Examination of peritumoral LVD in these patients might therefore help to estimate the risk of recurrence.     

Microbial Ecology and Association of Bacillus thuringiensis in Chicken Feces Originating from Feed

To explain the association of Bacillus thuringiensis (Bt) with animal feces, an ecological analysis in chickens was conducted by introducing a cry ^? strain marked by production of green fluorescent protein (GFP). After feeding with the tagged Bt strains, the feces of the tested chickens were collected at different times, isolated, and the morphology of Bt was observed. It was shown that Bt strain HD-73GFP in spore form could be isolated from feces of chickens for a period of 13 d, and then it disappeared thereafter. Bt could be detected only up to day 4 (but not thereafter), when chickens were fed with vegetative cells of HD-73GFP. To confirm the source of newly isolated strains, the gfp gene was examined by polymerase chain reaction (PCR), which showed that all the isolated strains harbored the marker gene. Recent data from isolation and PCR had suggested that fecal Bt strains had originated from food. Chicken tissues were thus dissected to isolate Bt strains and to investigate whether Bt could be located in vivo. Bt was located within the duodenum in spore form. Compared to the morphology of the isolated strains at different growth times, the growth rates of all the tested Bt had little changes when passing through the digestive system to the feces. Dissection of the chickens confirmed that Bt was safe for the tested animal.