New features of the cell wall of the radio-resistant bacterium Deinococcus radiodurans

We have analyzed the cell wall of the radio-resistant bacterium Deinococcus radiodurans. Unexpectedly, the bacterial envelope appears to be organized in different complexes of high molecular weight. Each complex is composed of several proteins, most of which are coded by genes of unknown function and the majority are constituents of the inner/outer membrane system. One of the most abundant complexes is constituted by the gene DR_0774. This protein is a type of secretin which is a known subunit of the homo-oligomeric channel that represents the main bulk of the type IV piliation family. Finally, a minor component of the pink envelope consists of several inner-membrane proteins. The implications of these findings are discussed.     

Isolation and characterization of a basic encephalitogenic protein from the central nervous system of sheep.

A basic protein has been purified from sheep brain. The purified protein sedimented in the analytical centrifuge at 56,000 r.p.m. as an homogenous product. This protein induced an allergic encephalitis when injected into guinea pigs. Some physiochemical properties of the protein were studied: the sedimentation coefficient was 1.52 and the molecular weight was 20,000 +/- 2,000, as estimated by electrophoresis in acrylamide gels containing SDS and urea; the specific extinction coefficient (see article) was 6.01 +/- 0.20. The aminoacid composition of the molecule was determined and its most prominent aspects are a high content of arginine and lysine, the presence of a single tryptophan, the total absence of cysteine and cystine and a blocked N-terminal residue. All these properties are very close to those of human and bovine encephalitogenic proteins.     

Towards molecular breeding of reproductive traits in cereal crops

The transition from vegetative to reproductive phase, flowering per se , floral organ development, panicle structure and morphology, meiosis, pollination and fertilization, cytoplasmic male sterility (CMS) and fertility restoration, and grain development are the main reproductive traits. Unlocking their genetic insights will enable plant breeders to manipulate these traits in cereal germplasm enhancement. Multiple genes or quantitative trait loci (QTLs) affecting flowering (phase transition, photoperiod and vernalization, flowering per se ), panicle morphology and grain development have been cloned, and gene expression research has provided new information about the nature of complex genetic networks involved in the expression of these traits. Molecular biology is also facilitating the identification of diverse CMS sources in hybrid breeding. Few Rf (fertility restorer) genes have been cloned in maize, rice and sorghum. DNA markers are now used to assess the genetic purity of hybrids and their parental lines, and to pyramid Rf or tms (thermosensitive male sterility) genes in rice. Transgene(s) can be used to create de novo CMS trait in cereals. The understanding of reproductive biology facilitated by functional genomics will allow a better manipulation of genes by crop breeders and their potential use across species through genetic transformation.     

Discovery and evaluation of nNav1.5 sodium channel blockers with potent cell invasion inhibitory activity in breast cancer cells

Voltage-gated sodium channels (VGSC) are a well-established drug target for anti-epileptic, anti-arrhythmic and pain medications due to their presence and the important roles that they play in excitable cells. Recently, their presence has been recognized in non-excitable cells such as cancer cells and their overexpression has been shown to be associated with metastatic behavior in a variety of human cancers. The neonatal isoform of the VGSC subtype, Na_v1.5 (nNa_v1.5) is overexpressed in the highly aggressive human breast cancer cell line, MDA-MB-231. The activity of nNa_v1.5 is known to promote the breast cancer cell invasion in vitro and metastasis in vivo, and its expression in primary mammary tumors has been associated with metastasis and patient death. Metastasis development is responsible for the high mortality of breast cancer and currently there is no treatment available to specifically prevent or inhibit breast cancer metastasis. In the present study, a 3D-QSAR model is used to assist the development of low micromolar small molecule VGSC blockers. Using this model, we have designed, synthesized and evaluated five small molecule compounds as blockers of nNa_v1.5-dependent inward currents in whole-cell patch-clamp experiments in MDA-MB-231 cells. The most active compound identified from these studies blocked sodium currents by 34.9?±?6.6% at 1?μM. This compound also inhibited the invasion of MDA-MB-231 cells by 30.3?±?4.5% at 1?μM concentration without affecting the cell viability. The potent small molecule compounds presented here have the potential to be developed as drugs for breast cancer metastasis treatment.     

Ginsenoside Rf, a component of ginseng, regulates lipoprotein metabolism through peroxisome proliferator-activated receptor alpha

We investigated whether ginseng regulates lipoprotein metabolism by altering peroxisome proliferator-activated receptor alpha (PPARalpha)-mediated pathways, using a PPARalpha-null mouse model. Administration of ginseng extract, ginsenosides, and ginsenoside Rf (Rf) to wild-type mice not only significantly increased basal levels of hepatic apolipoprotein (apo) A-I and C-III mRNA compared with wild-type controls, but also substantially reversed the reductions in mRNA levels of apo A-I and C-III expected following treatment with the potent PPARalpha ligand Wy14,643. In contrast, no effect was detected in the PPARalpha-null mice. Testing of eight main ginsenosides on PPARalpha reporter gene expression indicated that Rf was responsible for the effects of ginseng on lipoprotein metabolism. Furthermore, the inhibition of PPARalpha-dependent transactivation by Rf seems to occur at the level of DNA binding. These results demonstrate that ginseng component Rf regulates apo A-I and C-III mRNA and the actions of Rf on lipoprotein metabolism are mediated via interactions with PPARalpha.     

同功酶电泳在种群遗传研究中的应用

本文扼要介绍了同功酶的分类和酶带的命名;介绍了利用酶带的相对频率求算种群间遗传相似系数和遗传距离;也介绍了利用遗传相似系数进行聚类分析的两种方法．     

Genetic analysis of fertility restoration and accumulation of ORF125 mitochondrial protein in the kosena radish (Raphanus sativus cv. Kosena) and a Brassica napus restorer line

The genetics of fertility restoration (Rf) of kosena radish CMS has been characterized. The kosena CMS-Rf system is genetically the same as that of the ogura CMS-Rf system. Two dominant genes that act complementary to the restoration of fertility control fertility restoration in kosena CMS. One allele (Rf1) is associated with accumulation of the CMS-associated protein, ORF125. The interaction of Rf1 and another allele (Rf2) was essential for the restoration of fertility in radish, whereas Rf1 alone was sufficient for the complete restoration of fertility in the B. napus kosena CMS cybrid. Received: 13 August 1999 / Accepted: 16 September 1999     

一个玉米CMS-C恢复基因的精细定位

为挖掘玉米C型细胞质雄性不育(CMS-C,C-type cytoplasmic male sterility)的育性恢复基因并解析基因功能,用恢复系K932R与2个CMS-C同质异核不育系K169S和K932S分别构建2个F2定位群体,结合SSR分子标记和分离群体分析法全基因组重测序(BSA-reseq)技术定位育性恢...     

Molecular basis of cytoplasmic male sterility and fertility restoration in rice

Cytoplasmic male sterility (CMS) is a maternally inherited trait that causes dysfunctions in pollen and anther development. CMS is caused by the interaction between nuclear and mitochondrial genomes. A product of a CMS-causing gene encoded by the mitochondrial genome affects mitochondrial function and the regulation of nuclear genes, leading to male sterility. In contrast, the RESTORER OF FERTILITY gene (Rf gene) in the nuclear genome suppresses the expression of the CMS-causing gene and restores male fertility. An alloplasmic CMS line is often bred as a result of nuclear substitution, which causes the removal of functional Rf genes and allows the expression of a CMS-causing gene in mitochondria. The CMS/Rf system is an excellent model for understanding the genetic interactions and cooperative functions of mitochondrial and nuclear genomes in plants, and is also an agronomically important trait for hybrid seed production. In this review article, pollen and anther phenotypes of CMS, CMS-associated mitochondrial genes, Rf genes, and the mechanism that causes pollen abortion and its agronomical application for rice are described.