The application of RAPD markers in stock discrimination of the four-wing flyingfish, Hirundichthys affinis in the central western Atlantic

The polymerase chain reaction–random amplified polymorphic DNA (PCR–RAPD) technique was used to examine genetic variability and population structuring in the four-wing flyingfish, Hirundichthys affinis within the central western Atlantic. Three random decamer primers and pairs of these primers were used to amplify nuclear DNA from 360 fish sampled from six populations (at five locations) across the region. A total of 58 polymorphic RAPD markers were identified, 20 of which were population-specific and six of which were subregional or stock-specific markers. Cluster analysis of similarity indices indicated the presence of three genetically distinct subregional stocks located in the eastern Caribbean, southern Netherlands Antilles and Brazil, respectively. Estimates of gene diversity (φ) and gene flow ( Nm ) are consistent with this three-stock hypothesis. Furthermore, partially restricted gene flow was apparent among spatially and temporally separate sampled populations within the eastern Caribbean subregional stock, indicating the possible presence of different spawning groups. These results are entirely consistent with those obtained from PCR–RFLP analysis of the mtDNA D-loop in the same fish, indicating the presence of barriers to dispersal and interbreeding in both sexes. We conclude that the PCR–RAPD technique is suitable for determining population stock structure in this species and that a three-stock approach to managing H. affinis within the central western Atlantic would be appropriate.     

The development of branched silk gland nuclei

Nuclei in the giant polyploid silk gland cells of Calpodes ethlius grow by endomitosis and can develop hundreds of branches during larval life. The shape of the these nuclei is characteristic for each region of the gland. We have found shape to be correlated with arrangement of the nuclear matrix. Scanning electron microscopy showed nuclear matrices with shapes similar to those of feulgen stained nuclei. Profiles of isolated matrices seen by transmission electron microscopy had filaments aligned parallel to the long axis of nuclear branches. DNA stained by Hoechst had a similar parallel alignment within the branches. Nuclear shape may be maintained by a small number of components, since electrophoretic analysis showed only a few abundant polypeptides in the matrix fraction. Silk gland nuclei have some of the same nuclear matrix antigens found in smaller, more regularly shaped, eukaryote nuclei.     

中国山杨遗传多样性及遗传结构分析

利用6个单拷贝核基因标记,对中国山杨(Populus davidiana Dode)14个自然居群的遗传多样性和遗传分化水平进行了研究。结果表明,中国山杨表现出较高的遗传多样性水平,各居群间基因流(Nm)为0.66;居群内的变异占总变异的百分比(71.82%)大于居群间(28.18%)。Mantel test检验结果显示居群遗传距离和地理距离间没有相关性。失配分布检测显示中国山杨历史上曾经历过种群的扩张。复杂的种群历史动态、高度异交和较高的碱基突变速率是中国山杨遗传多样性水平较高的原因;而较强的花粉和种子扩散能力及中国山杨的连续分布可能是其居群间遗传分化较小的原因。     

Expression of cell growth and bone specific genes at single cell resolution during development of bone tissue-like organization in primary osteoblast cultures.

Primary cultures of calvarial derived normal diploid osteoblasts undergo a developmental expression of genes reflecting growth, extracellular matrix maturation, and mineralization during development of multilayered nodules having a bone tissue-like organization. Scanning electron microscopy of the developing cultures indicates the transition from the uniform distribution of cuboidal osteoblasts to multilayered nodules of smaller cells with a pronounced orientation of perinodular cells towards the apex of the nodule. Ultrastructural analysis of the nodule by transmission electron microscopy indicates that the deposition of mineral is confined to the extracellular matrix where cells appear more osteocytic. The cell body contains rough endoplasmic reticulum and golgi, while these intracellular organelles are not present in the developing cellular processes. To understand the regulation of temporally expressed genes requires an understanding of which genes are selectively expressed on a single cell basis as the bone tissue-like organization develops. In situ hybridization analysis using 35S labelled histone gene probes, together with 3H-thymidine labelling and autoradiography, indicate that greater than 98% of the pre-confluent osteoblasts are proliferating. By two weeks, both the foci of multilayered cells and internodular cell regions have down-regulated cell growth associated genes. Post-proliferatively, but not earlier, initial expression of both osteocalcin and osteopontin are restricted to the multilayered nodules where all cells exhibit expression. While total mRNA levels for osteopontin and osteocalcin are coordinately upregulated with an increase in mineral deposition, in situ hybridization has revealed that expression of osteocalcin and osteopontin occurs predominantly in cells associated with the developing nodules. In contrast, proliferating rat osteosarcoma cells (ROS 17/2.8) concomitantly express histone H4, along with osteopontin and osteocalcin. These in situ analyses of gene expression during osteoblast growth and differentiation at the single cell level establish that a population of proliferating calvarial-derived cells subsequently expresses osteopontin and osteocalcin in cells developing into multilayered nodules with a tissue-like organization.     

Use of matrix attachment regions (MARs) to minimize transgene silencing

Matrix attachment regions (MARs) are operationally defined as DNA elements that bind specifically to the nuclear matrix in vitro. It is possible, although unproven, that they also mediate binding of chromatin to the nuclear matrix in vivo and alter the topology of the genome in interphase nuclei. When MARs are positioned on either side of a transgene their presence usually results in higher and more stable expression in transgenic plants or cell lines, most likely by minimizing gene silencing. Our review explores current data and presents several plausible models to explain MAR effects on transgene expression.     

骨膜蛋白在肿瘤微环境中的作用研究进展

肿瘤微环境对肿瘤的发展起重要作用,而肿瘤微环境中的细胞外基质蛋白在肿瘤细胞增殖、转移、免疫逃逸及对化疗的耐药等生物特性调节中发挥着关键作用。充分理解肿瘤微环境中各分子相互作用机制并及时给予有效的干预措施,有助于探索新的治疗靶点并抑制肿瘤进展。近期研究表明,骨膜蛋白（periostin, POSTN）作为细胞外基质蛋白中的一种重要成分,参与了多种肿瘤的生物学过程,并与肿瘤微环境中多个环节相关。从肿瘤微环境出发,总结了骨膜蛋白在肿瘤发生发展中的最新研究进展,以探讨骨膜蛋白能否成为潜在的肿瘤治疗靶点。     

Molecular cloning and expression of the gene for a major leucine-rich protein from human hepatoblastoma cells (HepG2)

Summary The human hepatoblastoma cell line, HepG2, exhibits an array of stable properties in culture that have made it a popular cell culture model for studies on regulation of liver-specific gene expression and properties of hepatoma cells. In contrast to other hepatoma cell lines, HepG2 cells overexpress a characteristic detergent-extractable, wheat germ lectin-binding protein with apparent molecular mass of 130 kDa. Using an antibody to screen a phage expression library of HepG2 complementary DNA (cDNA), we identified and cloned a 4734 base pair cDNA which codes for a 130-kDa leucine-rich protein (lrp130) when expressed in transfected cells. The deduced sequence of lrp130 exhibits sequences weakly homologous to the consensus sequence for the ATP binding site in ATP-dependent kinases and the protein kinase C phosphorylation site of the epidermal growth factor receptor. Consistent with the higher levels of expression of lrp130 antigen, Northern hybridization analysis indicated that HepG2 cells express high levels of the major 4.8 kilobase lrp130 mRNA relative to other hepatoma cells. Although currently of unknown function, lrp130 may be of utility as a marker for liver cell lineages represented by the HepG2 cell line.     

CT联合肿瘤标志物与MRI联合肿瘤标志物对于直肠癌患者术前诊断的准确率与特异性的研究

目的:探讨CT联合肿瘤标志物与MRI联合肿瘤标志物对于直肠癌患者术前诊断的准确率与特异性,为大肠癌的术前诊断提供一定的理论依据。方法:选取我院在2015年01月至2016年01月间收治的86例直肠癌患者以及64例肠道良性病变患者分别作为观察组I组和观察II组的研究对象,另外选取来我院进行健康体检的80例人员作为对照组研究,分别分析CT联合肿瘤标志物与MRI联合肿瘤标志物(CEA、CA125、CA199、CA242、CA724)对大肠癌患者诊断的准确率与特异性之间的差别。结果:观察I组肿瘤标志物水平要明显高于观察II组和对照组,差异显著,具有统计学意义;肿瘤标志物CEA、CA125、CA199、CA242、CA724对大肠癌患者检测的阳性率分别为67.44%(58/86)、26.74%(23/86)、84.88%(73/86)、72.09%(62/86)、33.72%(29/86),肿瘤标志物并联检测对大肠癌的阳性检测率为94.19%(81/86)。CT联合肿瘤标志物对大肠癌的准确率为97.67%(84/86),特异性为94.44%(136/144);MRI联合肿瘤标志物对大肠癌的阳性检测率为100.00%(86/86),特异性为98.61%(142/144)。结论:CT联合肿瘤标志物对大肠癌诊断的准确率与特异性均不如MRI联合肿瘤标志物,因此MRI联合肿瘤标志物可作为大肠癌除病理学鉴定外最佳的诊断方式。     

BLCA-4 在膀胱癌中作用的研究进展

摘要：近年来,膀胱癌的发病率与死亡率呈逐年上升,已成为泌尿系统最常见的肿瘤。随着分子生物技术的不断发展,核基质蛋白(NMPs)、膀胱肿瘤抗原(BTA)、透明质酸和透明质酸酶(HA-HAase)、细胞角蛋白(CK)等诸多膀胱肿瘤标志物被发现。其中,膀胱癌特异性核基质蛋白-4(BLCA-4)是一种可溶性的复合物,在正常膀胱组织中不表达而存在于膀胱癌组织中。检测尿样中BLCA-4水平有望用于膀胱癌的筛查及诊断,具有较高的敏感性和特异性,也可用于普通人群与膀胱癌高危人群(脊髓损伤患者)的筛选与检测;而术后病理组织检测BLCA-4 的表达也可为膀胱癌患者的预后预测提供参考。本文对近年来BLCA-4 在膀胱癌中的作用进行了综述。