华西银腊梅挥发油化学成分的研究

用水蒸气蒸馏法提取华西银腊梅挥发油,并用气相色谱-质谱(GC-MS)联用技术对其挥发油的化学成分进行分析,结果共鉴定了其中的39种成分,所鉴定成分含量约占总检出量的87.83%。其化学成分主要为(Z,Z)-9,12-十八碳二烯酸甲酯(9.00%),壬醛(5.83%),二十一烷(5.69%),二十烷(5.08%),辛炔酸(4.50%),2,6,10,15-四甲基十七烷(3.93%),(Z)-6-十八烯酸甲酯(3.65%),3,8-二甲基十一烷(3.52%),1-十六碳炔(3.31%),肉豆蔻酸(2.86%),月桂醛(2.81%),壬酸(2.23%),5,6,7,7α-四氢-4,4,7α三甲基-2(4H)-苯并呋喃酮(2.18%)等。     

Yeast killer plasmid mutations affecting toxin secretion and activity and toxin immunity function.

M double-stranded RNA (MdsRNA) plasmid mutants were obtained by mutagenesis and screening of a diploid killer culture partially heat cured of the plasmid, so that a high proportion of the cells could be expected to have only on M plasmid. Mutants with neutral (nonkiller [K-], immune [R+]) or suicide (killer [K+], sensitive [R-] phenotypes were examined. All mutants became K- R- sensitives on heat curing of the MdsRNA plasmid, and showed cytoplasmic inheritance by random spore analysis. In some cases, M plasmid mutations were indicated by altered mobility of the MdsRNA by agarose gel electrophoresis or by altered size of in vitro translation products from denatured dsRNA. Neutral mutants were of two types: nonsecretors of the toxin protein or secretors of an inactive toxin. Of three neutral nonsecretors examined, one (NLP-1), probably a nonsense mutation, made a smaller protoxin precursor in vitro and in vivo, and two made full-size protoxin molecules. The in vivo protoxin of 43,000 molecular weight was unstable in the wild type and kinetically showed a precursor-product relationship to the processed, secreted 11,000-molecular-weight toxin. In one nonsecretor (N1), the protoxin appeared more stable in a pulse-chase experiment, and could be altered in a recognition site required for protein processing.     

Chemotaxonomic significance of the xanthomonadins,novel brominated aryl-polyene pigments produced by bacteria of the genus Xanthomonas

The cell pigments produced by strains of Xanthomonas spp. (including representatives of all five presently recognized taxospecies of these phytopathogenic bacteria) have been isolated as isobutyl esters, purified, and characterized in terms of electronic absorption, chromatographic and co-chromatographic, and mass spectrometric properties. This comparative examination reveals that these bacteria produce brominated aryl-polyene pigments which are given the trivial name xanthomonadins. The several xanthomonadins usually occur as mixtures which have been resolved by chromatography and sorted into several Pigment Groups, thus enabling a more rational approach in our on-going systematic study of their exact chemical structures and biosynthesis. From what is presently known, some of the xanthomonadins might differ from xanthomonadin I, the exact structure of which has previously been determined in material from Xanthomonas juglandis ICPB XJ103, by their being monobrominated (rather than dibrominated, as is xanthomonadin I), by their having the equivalent of one methyl group less than does xanthomonadin I, and/or in other ways. The pigments of Xanthomonas ampelina (a little known and possibly questionable member of this genus) seem somewhat different from the pigments of the other Xanthomonas spp. The ability to form these distinctive xanthomonadin pigments is a useful chemotaxonomic marker for the genus Xanthomonas, since such pigments are not known to be formed by taxonomically or ecologically adjacent bacteria. Sufficient characterization of this assemblage of xanthomonadin pigments is presented so that they can be isolated and identified routinely on the basis of the aforementioned properties.     

Unique Antibody Responses to Malondialdehyde-Acetaldehyde (MAA)-Protein Adducts Predict Coronary Artery Disease

Malondialdehyde-acetaldehyde adducts (MAA) have been implicated in atherosclerosis. The purpose of this study was to investigate the role of MAA in atherosclerotic disease. Serum samples from controls (n = 82) and patients with; non-obstructive coronary artery disease (CAD), (n = 40), acute myocardial infarction (AMI) (n = 42), or coronary artery bypass graft (CABG) surgery due to obstructive multi-vessel CAD (n = 72), were collected and tested for antibody isotypes to MAA-modifed human serum albumin (MAA-HSA). CAD patients had elevated relative levels of IgG and IgA anti-MAA, compared to control patients (p<0.001). AMI patients had a significantly increased relative levels of circulating IgG anti-MAA-HSA antibodies as compared to stable angina (p<0.03) or CABG patients (p<0.003). CABG patients had significantly increased relative levels of circulating IgA anti-MAA-HSA antibodies as compared to non-obstructive CAD (p<0.001) and AMI patients (p<0.001). Additionally, MAA-modified proteins were detected in the tissue of human AMI lesions. In conclusion, the IgM, IgG and IgA anti-MAA-HSA antibody isotypes are differentially and significantly associated with non-obstructive CAD, AMI, or obstructive multi-vessel CAD and may serve as biomarkers of atherosclerotic disease.     

The K1 Toxin of Saccharomyces cerevisiae Kills Spheroplasts of Many Yeast Species

The Saccharomyces cerevisiae K1 toxin killed spheroplasts from the genera Candida, Kluyveromyces, and Schwanniomyces. Cells of these organisms were toxin insensitive. The toxin bound poorly to Kluyveromyces lactis cells. In contrast, Candida albicans bound the toxin to an extent similar to that seen with S. cerevisiae. Thus, wall receptors can define toxin specificity and are necessary but not sufficient for toxin action on intact cells.     

Yeast Kre1p is a cell surface O-glycoprotein

The Saccharomyces cerevisiae KRE1 gene encodes a secretory protein required for the production of the cell wall polymer (1 6)--glucan. Here we report further characterization of the KRE1 gene product, Krelp. A functional, epitope-tagged Krelp is shown to be highly modified in a SEC53-dependent manner. Krelp is O-glycosylated, but the basis for the majority of its post-translational modification is unknown. Fractionation of Kre1p reveals a cell wall-associated form and a less abundant membrane-associated species. Indirect immunoflurorescence demonstrates that Kre1p localizes to the cell surface, where it becomes concentrated at the surface of mother cells. Such a localization of Kre1p seems to parallel the CAL1/CSD2-dependent cell wall deposition of chitin found in S. cerevisiae, and is consistent with evidence from Schizophyllum commune that (1 6)--glucan accumulates during maturation of the subapical region of the wall distal to the hyphal tip.     

CWH41 encodes a novel endoplasmic reticulum membrane N-glycoprotein involved in beta 1,6-glucan assembly.

CWH41 encodes a novel type II integral membrane N-glycoprotein located in the endoplasmic reticulum. Disruption of the CWH41 gene leads to a K1 killer toxin-resistant phenotype and a 50% reduction in the cell wall beta 1,6-glucan level. CWH41 also displays strong genetic interactions with KRE1 and KRE6, two genes known to be involved in the beta 1,6-glucan biosynthetic pathway. The cwh41 delta kre6 delta double mutant is nonviable; and the cwh41 delta kre1 delta double mutation results in strong synergistic defects, with a severely slow-growth phenotype, a 75% reduction in beta 1,6-glucan level, and the secretion of a cell wall glucomannoprotein, Cwp1p. These results provide strong genetic evidence indicating that Cwh41p plays a functional role, possibly as a new synthetic component, in the assembly of cell wall beta 1,6-glucan.     

Object memory and perception in the medial temporal lobe: an alternative approach

The medial temporal lobe (MTL) includes several structures--the hippocampus, and the adjacent perirhinal, entorhinal and parahippocampal cortices--that have been associated with memory for at least the past 50 years. These components of the putative 'MTL memory system' are thought to operate together in the service of declarative memory--memory for facts and events--having little or no role in other functions such as perception. Object perception, however, is thought to be independent of the MTL, and instead is usually considered to be the domain of the ventral visual stream (VVS) or 'what' pathway. This 'textbook' view fits squarely into the prevailing paradigm of anatomical modularisation of psychological function in the brain. Recent studies, however, question this view, indicating that first, the MTL is functionally heterogeneous, and second, structures in the MTL might have a role in perception. Furthermore, the specific contributions of the individual structures within the MTL are being elucidated. These new findings indicate that it might no longer be useful to assume a strict functional dissociation between the MTL and the VVS, and that psychological functions might not be modularised in the way usually assumed. We propose an alternative approach to understanding the functions of these brain regions in terms of what computations they perform, and what representations they contain.     

An interactional network of genes involved in chitin synthesis in Saccharomyces cerevisiae

Background

The identification of disease-associated genes using single nucleotide polymorphisms (SNPs) has been increasingly reported. In particular, the Affymetrix Mapping 10 K SNP microarray platform uses one PCR primer to amplify the DNA samples and determine the genotype of more than 10,000 SNPs in the human genome. This provides the opportunity for large scale, rapid and cost-effective genotyping assays for linkage analysis. However, the analysis of such datasets is nontrivial because of the large number of markers, and visualizing the linkage scores in the context of genome maps remains less automated using the current linkage analysis software packages. For example, the haplotyping results are commonly represented in the text format.

Results

Here we report the development of a novel software tool called CompareLinkage for automated formatting of the Affymetrix Mapping 10 K genotype data into the "Linkage" format and the subsequent analysis with multi-point linkage software programs such as Merlin and Allegro. The new software has the ability to visualize the results for all these programs in dChip in the context of genome annotations and cytoband information. In addition we implemented a variant of the Lander-Green algorithm in the dChipLinkage module of dChip software (V1.3) to perform parametric linkage analysis and haplotyping of SNP array data. These functions are integrated with the existing modules of dChip to visualize SNP genotype data together with LOD score curves. We have analyzed three families with recessive and dominant diseases using the new software programs and the comparison results are presented and discussed.

Conclusions

The CompareLinkage and dChipLinkage software packages are freely available. They provide the visualization tools for high-density oligonucleotide SNP array data, as well as the automated functions for formatting SNP array data for the linkage analysis programs Merlin and Allegro and calling these programs for linkage analysis. The results can be visualized in dChip in the context of genes and cytobands. In addition, a variant of the Lander-Green algorithm is provided that allows parametric linkage analysis and haplotyping.     

Characterization of the yeast KEX1 gene product: a carboxypeptidase involved in processing secreted precursor proteins.

We have identified and partially characterized the Saccharomyces cerevisiae KEX1 gene product, Kex1p, to assess its role in processing secreted protein precursors. Anti-Kex1p antibodies identified a 113-kilodalton protein that was absent in cells in which the KEX1 gene has been disrupted and that was more abundant in cells overexpressing the KEX1 gene. Kex1p was found to be a membrane-associated glycoprotein with N-linked carbohydrate. The N-linked oligosaccharide(s) was modified in a progressive manner after synthesis, causing the glycoprotein to slowly increase in mass to 115 kilodaltons. After a Kex2p-mediated cleavage event at specific pairs of basic amino acids, alpha-factor and K1 killer toxin precursors have COOH-terminal dibasic residue extensions and require a carboxypeptidase B-like enzyme to process the precursors to maturity. A carboxypeptidase activity, with apparent specificity for basic amino acids, was detected in KEX1 cells. Disruption of the KEX1 gene abolished this activity, while overexpression of KEX1 increased it. Our results provide biochemical evidence consistent with earlier genetic work, that KEX1 encodes a serine carboxypeptidase involved in the processing of precursors to secreted mature proteins.