Selective modulation of band 4.1 binding to erythrocyte membranes by protein kinase C

We have studied the effects of band 4.1 phosphorylation on its association with red cell inside-out vesicles stripped of all peripheral proteins. Band 4.1 bound to these vesicles in a saturable manner, and binding was characterized by a linear Scatchard plot with an apparent Kd of 1-2 x 10(-7) M. Phosphorylation of band 4.1 by purified protein kinase C reduced its ability to bind to membranes, resulting in a reduction in the apparent binding capacity of the membrane by 60-70% but little or no change in the apparent Kd of binding. By contrast, phosphorylation of band 4.1 by cAMP-dependent kinase had no effect on membrane binding. Digestion of the stripped inside-out vesicles with trypsin cleaved 100% of the cytoplasmic domain of band 3 but had little or no effect on glycophorin. Binding of band 4.1 to these digested vesicles was reduced by 70%. Phosphorylation of band 4.1 by protein kinase C had no effect on its binding to the digested vesicles, suggesting that the cytoplasmic domain of band 3 contained the phosphorylation-sensitive binding sites. This was confirmed by direct measurement of band 4.1 binding to the purified cytoplasmic domain of band 3. Phosphorylation of band 4.1 by protein kinase C reduced its binding to the purified 43-kDa domain by as much as 90%, while phosphorylation by cAMP-dependent kinase was without effect. These results show a selective effect of protein kinase C phosphorylation on the binding of band 4.1 to one of its membrane receptors, band 3, and suggest a mechanism whereby one of the key red cell-skeletal membrane associations may be modulated.     

Recent Advances in Understanding Proteins Involved in Lipid Droplet Formation,Growth and Fusion

Lipid droplets （LDs） were once viewed as simple, inert lipid micelles. However, they are now known to be organelles with a rich proteome involved in a myriad of cellular processes. LDs are heterogeneous in nature with different sizes and compositions of phospholipids, neutral lipids and proteins. This review takes a focused look at the roles of proteins involved in the regulation of LD formation, expansion, and morphology. The related proteins are summarized such as the fat-specific protein （Fsp27）, fat storage-inducing trans- membrane （FIT） proteins, seipin and ADP-ribosylation factor 1-coat protein complex I （Arf-COPI）. Finally, we present important challenges in LD biology for a deeper understanding of this dynamic organelle to be achieved.     

长时程增强诱导和维持过程中海马CA1区神经细胞粘附分子蛋白水平与mRNA表达的变化

既往研究发现,神经细胞粘附分子(neural cell adhesion molecules,NCAM)对海马CA1区突触传递长时程增强(longterm potentiation,LTP)的诱导和维持极为关键。本文采用原位杂交法和Western blot法,观察了大鼠海马腑片LTP诱导和维持过程中NCAM mRNA和蛋白水平的动态变化过程。结果显示,强直刺激诱发fEPSP斜率升高10 min时,海马CA1区NCAM mRNA染色阳性神经元数量显著增加(76.6±11.5个),NCAM蛋白水平亦明显升高(7.190±0.64任意单位/50μg蛋白)。强直刺激诱发fEPSP斜率升高1 h时,NCAM mRNA染色阳性神经元数量为73.3±14.0个,NCAM蛋白量为9.031±0.71任意单位/50 μg蛋白;与强直刺激后10 min比较,NCAM mRNA表达无显著变化,而NCAM蛋白水平变化明显。NMDA受体特异阻断剂AP-5在损害LTP的同时,显著抑制NCAM mRNA和蛋白的增加。实验结果表明,在大鼠海马LTP诱导和维持过程中,NCAM mRNA增强的表达相对稳定,而NCAM蛋白水平呈现先低后高的变化。     

~（60）Co－γ射线诱变柠檬酸产生菌黑曲霉Co9－6的研究

本试验采用￣（６０）Ｃｏ－γ射线对柠檬酸产生菌黑曲霉Ｃｏ９－６进行辐射,经两次处理后选育出Ｌ１２１７和Ｌ８０１两株优良柠檬酸产生菌。中试结果表明菌株Ｌ１２１７较Ｌ８０１更优：产酸率较菌株Ｃｏ９－６提高１７．６％、发酵周期缩短１３．４％、对糖转化率提高１３．３％。     

The expression of a novel estrogen receptor, GPR30, in epithelial ovarian carcinoma and its correlation with MMP-9

The aim of the present study is to investigate the expression of a novel estrogen receptor, G protein-coupled receptor 30 (GPR30) and its correlation with matrix metalloproteinases-9 (MMP-9) in epithelial ovarian cancer (EOC). Ovary tissues were obtained from 39 female patients, including 30 cases of EOC and 9 cases of benign ovarian tumor. Four normal ovary tissues were used as control. Immunohistochemical staining was used to detect the expressions of GPR30 and MMP-9. Chi square test, Fisher's exact test and Spearman's rank correlation analysis were used for statistical analysis. The results showed that GPR30 overexpression rate in EOC cases was significantly higher than those in benign ovarian tumor and normal ovary cases. Whereas MMP-9 overexpression rate in EOC cases was significantly higher than that in normal ovary cases, without any difference to that in benign ovarian tumor cases. To demonstrate the relationship between GPR30 and clinicopathological variables of EOC, we further analyzed the pathology type, FIGO stage and age of patients sampled in our study. The analysis showed there were significant differences of GPR30 overexpression rate among various pathology types and different FIGO stages (P<0.05), and no significant difference of both GPR30 and MMP-9 among three age groups (P>0.05). Moreover, GPR30 expression was positively correlated with MMP-9 (r(s)=1.000, P=0.002). These results suggest that GPR30 may be involved in the invasion and metastasis of EOC, being a potential index of EOC early diagnosis and malignancy grade prediction.     

Oligodendrocytes regulate formation of nodes of Ranvier via the recognition molecule OMgp

The molecular mechanisms underlying the involvement of oligodendrocytes in formation of the nodes of Ranvier (NORs) remain poorly understood. Here we show that oligodendrocyte-myelin glycoprotein (OMgp) aggregates specifically at NORs. Nodal location of OMgp does not occur along demyelinated axons of either Shiverer or proteolipid protein (PLP) transgenic mice. Over-expression of OMgp in OLN-93 cells facilitates process outgrowth. In transgenic mice in which expression of OMgp is down-regulated, myelin thickness declines, and lateral oligodendrocyte loops at the node-paranode junction are less compacted and even join together with the opposite loops, which leads to shortened nodal gaps. Notably, each of these structural abnormalities plus modest down-regulation of expression of Na(+) channel alpha subunit result in reduced conduction velocity in the spinal cords of the mutant mice. Thus, OMgp that is derived from glia has distinct roles in regulating nodal formation and function during CNS myelination.     

Modulation of drug permeability in Chinese hamster ovary cells. Possible role for phosphorylation of surface glycoproteins.

We have previously reported that the uptake of colchicine and other drugs in Chinese hamster ovary (CHO) cells can be greatly enhanced by the addition of metabolic inhibitors such as cyanide (See, Y.P., Carlsen, S.A., Till, J.E. and Ling, V. (1974) Biochim. Biophys. Acta 373, 242-252). This has led us to postulate the presence of an active drug permeability barrier in these cells. In this paper we provide evidence for the dependence of this permeability barrier on intracellular ATP levels. Colchicine-resistant mutants of CHO cells exhibiting a reduced drug permeability, however, can maintain this drug permeability barrier at much lower ATP levels, suggesting that they possess an altered active drug permeability barrier. We have also observed a membrane-associated protein kinase-phosphoprotein phosphatase system in the isolated membranes of mutant and wild-type cells. Differences in the intrinsic protein phosphorylation patterns between the membranes of these cells have led us to conclude that the control of the drug permeability barrier may be mediated via the phosphorylation of at least two high molecular weight surface glycoproteins.     

Association between cyclooxygenase-2 gene polymorphisms and risk of periodontitis: a meta-analysis involving 5653 individuals

There ?765G > C, ?1195G > A, and 8473T > C polymorphisms in cyclooxygenase-2 (COX-2) gene polymorphisms and periodontitis risk were investigated based on published studies; however, their results could not give a conclusive result. Hence, we performed this meta-analysis of six published studies with eight case–control studies including these three polymorphisms which searched from PubMed and Web of Science up to October 15th, 2013. Odds ratios (ORs) with corresponding 95 % confidence intervals (CIs) were calculated to evaluate the association between the three polymorphisms of COX-2 and periodontitis risk. The results from 2,580 periodontitis patients and 3,073 healthy controls showed that none of ?765G > C, ?1195G > A, or 8473T > C polymorphism was not associated with periodontitis susceptibility [Take ?765G > C for example: OR = 0.94, 95 % CI = (0.57–1.53) for C vs. G; OR = 2.34, 95 % CI = (0.72–7.62) for CC vs. GG; OR = 0.68, 95 % CI = (0.46–1.01) for CG vs. GG; OR = 0.81, 95 % CI = (0.52–1.27) for (CG+GG) vs. GG; OR = 2.57, 95 % CI = (0.80–8.29) for CC vs. (GG+CG)]. In subgroup analyses according to the type of periodontitis and ethnicity for ?765G > C and ?1195G > A, and deviations in Hardy–Weinberg equilibrium for ?765G > C, we only observe a boundary association between ?1195G > A polymorphism and Asian population. However, due to limitations of this meta-analysis, the results should treat with caution and we suggest the further researches should be carried out to verify our results.