20种山茶科植物的叶表皮微形态研究

为解决一些山茶科(Theaceae)的分类学问题,该研究在光学显微镜下对山茶科2亚科6属共20种植物的13种叶表皮微形态特征进行了观察,并利用聚类分析和主成分分析对这些特征进行分析,为山茶科的科学分类提供参考资料。结果表明:(1)山茶科20种植物的13种叶表皮微形态特征能够区分种间差异和分类等级,显示了比较全面的分类价值。(2)基于微形态特征的聚类分析和主成分分析结果显示,20个种分为2个大类群以及10个分支,很好地区分了山茶亚科(Theoideae)与厚皮香亚科(Ternstroemoideae),并将大部分分类地位相近的物种归类到一起,较好地反映了物种之间的亲缘关系。(3)该研究结果支持将小黄花茶组(Sect.Luteoflora)作为独立的一个组;支持将重庆山茶(Camellia chungkingensis Chang)从瘤果茶组(Sect.Tuberculata Chang Tax.)中分离;支持将山茶亚科与厚皮香亚科划分为两个较大类群,认为将厚皮香亚科并入五列木科(Pentaphylacaceae)的观点还有待更多实验证据的支持。     

Cell culture medium supplemented with taurine decreases basic charge variant levels of a monoclonal antibody

Objective

To explore the impact of taurine on monoclonal antibody (mAb) basic charge variants in Chinese hamster ovary (CHO) cell culture.

Results

In fed-batch culture, adding taurine in the feed medium slightly increased the maximum viable cell density and mAb titers in CHO cells. What’s more, taurine significantly decreased the lysine variant and oxidized variant levels, which further decreased basic variant contents from 32 to 27%. The lysine variant content in the taurine culture was approximately 4% lower than that in control condition, which was the main reason for the decrease in basic variants. Real-time PCR and cell-free assay revealed that taurine played a critical role in the upregulation of relative basic carboxypeptidase and stimulating extracellular basic carboxypeptidase activities.

Conclusion

Taurine exhibits noticeable impact on lower basic charge variants, which are mainly due to the decrease of lysine variant and oxidized protein variants.

     

重庆特有种子植物区系特征研究

基于野外调查和文献查询,统计重庆地区特有种子植物数量,分析论述了重庆特有种子植物区系特征。结果表明:(1)重庆特有种子植物共有153种,隶属于40科97属;这些特有植物中,草本最多,有103种,灌木、乔木次之。(2)地理成分复杂多样,种子植物科包含6个分布类型及1个变型;属包含8个分布类型及10个变型;种则依据重庆市生态功能区划分为11个类型。(3)科级水平上,热带-亚热带性质占57.14%,温带性质占42.86%;属级水平上,热带-亚热带性质占23.53%,温带性质占64.71%;体现了该区从热带向温带过渡的性质。(4)重庆特有种子植物具有明显分布中心,其分布多度序列为:金佛山常绿阔叶林生物多样性保护生态功能区大巴山生物多样性保护与水土保持生态功能区市郊水源水质保护生态功能区消落带人工湿地水质保护生态功能区。     

Role of cytokine gene polymorphisms on prognosis in hepatocellular carcinoma after radical surgery resection

This study aimed to determine whether SNPs of cytokine genes influence survival of hepatocellular carcinoma (HCC) patients after radical surgery resection. We evaluated 14 SNPs of eight cytokine genes in 263 patients treated with radical surgery resection of HCC. Categorical variables were compared by the χ² test and Fisher's exact test. The Kaplan–Meier methods with log-rank test and Cox regression models were used to compare survival of resected HCC patients according to the genotype. Among the 14 studied SNPs of cytokine genes, only the TNF-α-863 (CA + CC) genotypes were revealed to be significant independent predictors of prolonged overall survival (OS) after HCC radical surgery resection (HR: 0.586, 95% CI: 0.355–0.968), considering for other clinical factors in a Cox proportional hazard model. Meanwhile, no significant association was found between the 14 SNPs and relapse-free survival (RFS) of resected HCC patients. In addition, combination analysis with the Th1 cytokine (IFN-γ, IL-2, IL-12B, TGF-β1) or Th2 cytokine (IL-6, IL-10) genetic polymorphisms by the Kaplan–Meier method and Cox multivariate analysis did not reveal any significant association between OS and RFS of resected HCC patients.     

Autophagy Reduces Neuronal Damage and Promotes Locomotor Recovery via Inhibition of Apoptosis After Spinal Cord Injury in Rats

Autophagy is an intracellular catabolic mechanism that maintains the balance of proteins, lipids and aging organelles. 3-Methyladenine (3-MA) is a selective inhibitor of autophagy, whereas rapamycin, an antifungal agent, is a specific inducer of autophagy, inhibiting the protein mammalian target of rapamycin. In the present study, we examined the role of autophagy, inhibited by 3-MA and enhanced by rapamycin, in a model of acute spinal cord injury in rats. We found that rapamycin could significantly increase the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin1 at the injury site. At the same time, the number of neurons and astrocytes with LC3 positive in the spinal cord was upregulated with time. In addition, administration of rapamycin produced an increase in the Basso, Beattie and Bresnahan scores of injured rats, indicating high recovery of locomotor function. Furthermore, expression of the proteins Bcl-2 and Bax was upregulated and downregulated, respectively. By contrast, the results for rats treated with 3-MA, which inhibits autophagy, were the opposite of those seen with the rapamycin-treated rats. These results show that induction of autophagy can produce neuroprotective effects in acute spinal cord injury in rats via inhibition of apoptosis.     

Identification of a mosquitocidal toxin from Bacillus thuringiensis using mass spectrometry

The Bacillus thuringiensis strain S2160-1 has previously been identified as being highly toxic to mosquito larvae and a viable alternative to strains currently used commercially to control these insects. A PCR approach had identified the presence of four putative insecticidal toxin genes (cry30Ea, cry30 Ga, cry50Ba and cry54Ba) in this strain, but did not identify the genes that encoding three of the main crystal toxin proteins of size 140 and 130 and 30 kDa. In this study we used mass spectrometry to identify the 130 kDa toxin as a rare Cry4 toxin (Cry4Cb3). The gene encoding this toxin was cloned and expressed and the toxin shown to have mosquitocidal activity against Culex quinquefasciatus.     

紫花苜蓿对铜胁迫生理响应的傅里叶变换红外光谱法研究

为阐明紫花苜蓿(Medicago sativa L.)对铜胁迫的耐性机理,采用准确度好、分辨率高和简便快捷的傅里叶变换红外光谱法(FTIR)研究在不同铜浓度(0、1、5、20、100 mol/L)处理时紫花苜蓿根、茎、叶化学组分的变化。结果表明:随着铜处理浓度的增加,紫花苜蓿根、茎、叶生物量变化不大。其根组织在2924 cm~(-1)处峰高处呈现出先下降后上升的趋势,反映了在低铜(5 mol/L)处理条件下紫花苜蓿分泌的有机酸不断螯合Cu,造成羧酸0-H的减少,但随着Cu含量的升高,其羧酸螯合力变弱,有机酸含量渐渐升高;根组织在1381 cm~(-1)处峰高先下降后上升,反映了含油脂化合物含量先下降后升高。可能与植物在细胞壁结构上增强抗逆性有一定关系,即低Cu处理下细胞壁可能通过提高阳离子交换能力(CEC),增强了耐Cu性;茎组织在2924,1643,1381,1064 cm~(-1)等处峰高无明显变化;叶组织所有峰值在低浓度(5 mol/L)Cu处理下变化不明显,高浓度(5 moL/L)Cu处理下所有峰值先升后降,随着这可能与可溶性糖及可溶性蛋白质等物质含量都呈现先升后降的趋势有关。这表明紫花苜蓿通过根部有机酸含量的变化和提高细胞壁阳离子交换能力,将吸收的Cu大部分积累在根部,阻止Cu向地上部分运输,有效地保护了植物地上部分组织。