Structures and magnetic properties of mono-doped fullerenes C59Xn and C59X(6mn)m (X=Bm,N+, P+, As+, Si): isoelectronic analogues of C60 and C60(6m)

Structures of mono-doped fullerenes, C59Xn and C59X(6mn)m (X=Bm, N+, P+, As+, Si), the isoelectronic analogues to C60 and C606m with 60 and 66 pi-electrons, have been investigated at the B3LYP/6-31G* level of density functional theory. On the basis of the computed nucleus independent chemical shifts (NICS) at the cage center and also at the center of individual rings as magnetic criteria, heterofullerenes with 60 pi-electrons are as aromatic as the parent C60, while those with 66 pi-electrons are much less aromatic than C606m. The very distinct endohedral chemical shifts of the 66 pi-electron systems may be useful to identify the heterofullerenes through their endohedral 3He NMR chemical shifts.     

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.     

A sensitive signal-on assay for MTase activity based on methylation-responsive hairpin-capture DNA probe

This work develops a simple, sensitive and signal-on electrochemical sensor for methyltransferase (MTase) activity analysis. The sensor is composed of a methylene blue-modi?ed "signaling DNA probe" and a "capture DNA probe" tethered methylation-responsive hairpin DNA (hairpin-capture DNA probe). The thiol- modified hairpin-capture DNA probe at 5' end was firstly self-assembled on gold electrode via Au-S bonding. Methylation-induced scission of hairpin-capture DNA probe would displace the hairpin section and remain the "capture DNA probe" section on the gold electrode. Subsequently, the remained "capture DNA probe" on the gold electrode can hybridize with the methylene blue-modi?ed "signaling DNA probe", mediating methylene blue onto the gold electrode surface to generate redox current. It was eT on state. The developed facile signal-on electrochemical sensing system showed a linear response to concentration of Dam MTase range from 0.1 to 1.0 U/mL. The detection limit of Dam MTase activity was determined to be 0.07 U/mL and the total detection time is 7h. The sensor also has the ability to provide information about the dynamics of methylation process. Furthermore, we demonstrated that this sensor could be utilized to screen inhibitors or drugs for Dam MTase.     

NIRF, a novel ubiquitin ligase, interacts with hepatitis B virus core protein and promotes its degradation

Hepatitis B virus (HBV) core protein (HBc) is a major component of viral nucleocapsid and a multifunctional protein involved in viral maturation and release. It is unstable and present in cells at low level because of K96 lysine residue, which is a ubiquitin acceptor site. Np95/ICBP90-like RING finger protein (NIRF) has auto-ubiquitination activity which is the hallmark of a ubiquitin ligase. In the present study, ubiquitin ligase, NIRF, binds to HBc and leads to the proteasome-mediated degradation of HBc in vivo. NIRF down-regulates HBc protein level, resulting in the decrease of the amount of HBV particles in supernatant of HepG2.2.15 cells. However knockdown of NIRF significantly increases endogenous HBc protein level, leading to HBV release. The results reveal that NIRF interacts with HBc and promotes the degradation of HBc in vivo. The pathway of NIRF-mediated ubiquitin–proteasome affects the release of HBV particles by controlling the amounts of HBc. It indicates that NIRF may participate in the maturation of HBV.     

The Impact of Iodine Excess on Thyroid Hormone Biosynthesis and Metabolism in Rats

Thyroid function ultimately depends on appropriate iodine supply to the gland. There is a complex series of checks and balances that the thyroid uses to control the orderly utilization of iodine for hormone synthesis. The aim of our study is to evaluate the mechanism underlying the effect of iodine excess on thyroid hormone metabolism. Based on the successful establishment of animal models of normal-iodine (NI) and different degrees of high-iodine (HI) intake in Wistar rats, the content of monoiodotyrosine (MIT), diiodotyrosine (DIT), T₄, and T₃ in thyroid tissues, the activity of thyroidal type 1 deiodinase (D1) and its (Dio1) mRNA expression level were measured. Results showed that, in the case of iodine excess, the biosynthesis of both MIT and DIT, especially DIT, was increased. There was an obvious tendency of decreasing in MIT/DIT ratio with increased doses of iodine intake. In addition, iodine excess greatly inhibited thyroidal D1 activity and mRNA expression. T₃ was greatly lower in the HI group, while there was no significant difference of T₄ compared with NI group. The T₃/T₄ ratio was decreased in HI groups, antiparalleled with increased doses of iodine intakes. In conclusion, the increased biosyntheses of DIT relative to MIT and the inhibition of thyroidal Dio1 mRNA expression and D1 activity may be taken as an effective way to protect an organism from impairment caused by too much T₃. These observations provide new insights into the cellular regulation mechanism of thyroid hormones under physiological and pathological conditions.     

Spindlin1, a novel nuclear protein with a role in the transformation of NIH3T3 cells

spindlin1, a novel human gene recently isolated by our laboratory, is highly homologous to mouse spindlin gene. In this study, we cloned cDNA full-length of this novel gene and send it to GenBank database as spindlin1 (Homo sapiens spindlin1) with Accession No. AF317228. In order to investigate the function of spindlin1, we studied further the subcellular localization of Spindlin1 protein and the effects of spindlin1 overexpression in NIH3T3 cells. The results showed that the fusion protein pEGFP-N1-spindlin1 was located in the nucleus and the C-terminal is correlated with nuclear localization of Spindlin1 protein. NIH3T3 cells which could stably express spindlin1 as a result of RT-PCR analysis compared with the control cells displayed a complete morphological change; made cell growth faster; and increased the percentage of cells in G2/M and S phase. Furthermore, overexpressed spindlin1 cells formed colonies in soft agar in vitro and formed tumors in nude mice. Our findings provide direct evidence that spindlin1 gene may contribute to tumorigenesis.     

生物转化生产D-塔格糖的食品级菌种选育及L-阿拉伯糖异构酶的克隆表达

L-阿拉伯糖异构酶(L-arabinose isomerase,L-AI)是一种可以催化D-半乳糖为D-塔格糖的胞内异构化酶。随着塔格糖在食品工业中越来越广泛的应用,能够将半乳糖转化为塔格糖的食品级微生物以及食品级来源的L-AI受到更大的关注。文中从各种酸奶制品、泡菜及其他一些食品中采集不同的样品,筛选出1株具有L-AI酶活的食品级菌株,经过生理生化鉴定以及16S rDNA序列测定,确定该菌株为戊糖片球菌,命名为Pediococcus pentosaceus PC-5。以该菌基因组为模板,克隆L-AI基因,并在大肠杆菌BL21成功地异源表达。表达产物经粗提取后,在40℃下加入Mn2+,使D-半乳糖转化为D-塔格糖的转化率为33%。     

Secretory delivery of heterologous proteins in attenuated <Emphasis Type="Italic">Vibrio anguillarum</Emphasis> for potential use in vaccine design

To synthesize and secrete heterologous proteins in an attenuated Vibrio anguillarum strain for potential multivalent live vaccine development, different antigen-delivery systems based on bacterial-originated secretion signal peptides (SPs) were designed and identified in this work. Four SPs were derived from hemolysin of Escherichia coli, RTX protein of V. cholerae, hemolysin of V. anguillarum, zinc-metalloprotease of V. anguillarum, respectively, and their abilities to support secretion of green fluorescent protein (GFP) in an attenuated V. anguillarum strain MVAV6203 were assayed. Immunodetection of GFP showed that the capability of the tested signal leaders to direct secretion of GFP varied greatly. Although all the four signal peptide-fused GFPs could be expressed correctly and trapped intracellularly in recombinant strains, only the EmpA signal peptide could confer efficient secretion to GFP. For the investigation of its potential application in live bacteria carrier vaccines, a heterologous protein EseB of Edwardsiella tarda was fused to the SP(empA) antigen-delivery system and introduced into the strain MVAV6203. Further analysis of EseB demonstrated that the constructed SP(empA) antigen-delivery system could be used to secrete foreign protein in attenuated V. anguillarum and be available for carrier vaccines development.     

Amplification, analysis and chromosome mapping of novel homeobox-containing and homeobox-flanking sequences in rice

Homeobox genes, widely distributed among animal and plant kingdoms, play an important role in developmental process. Several homeobox conserved fragments were amplified by PCR and the flanking regions were also obtained by an LM-PCR procedure. Sequencing and Southern analysis showed that they belong to a homeobox gene family of rice. Six homeobox-containing fragments were mapped on the molecular linkage map of rice. They were located on chromosomes 3, 4 and 7 respectively. It is noteworthy that there are 4 homeobox fragments located on rice chromosome 3 and the result is also consistent with the comparative genomics between rice and maize.