Comparison of kinetic properties between MSS4 and Rab3A GRF GDP/GTP exchange proteins

The kinetic properties of MSS4 are studied in comparison with those of Rab3A GRF. MSS4 stimulates the dissociation of [³H]GDP from the lipid-modified and lipid-unmodified forms of Rab3A to the same extent, although Rab3A GRF is more effective on the lipid-modified form than on the lipid-unmodified form. Both MSS4 and Rab3A GRF are inactive on other Rab/Sec/Ypt family members including at least Rab2, Rab5, and Rab11. Rab GDI inhibits the MSS4 and Rab3A GRF effects on the lipid-modified form of Rab3A, but the doses of Rab GDI necessary for this inhibitory effect on Rab3A GRF are lower than those on MSS4. Moreover, Rab GDI slightly inhibits the Rab3A GRF effect on the lipid-unmodified form of Rab3A, but does not affect the MSS4 effect on the lipid-unmodified form of Rab3A. These results suggest that MSS4 and Rab3A GRF are different GDP/GTP exchange proteins for Rab3A.     

鲁西、南平原农作区小型兽类群落组成及季节变化

作者于１９９２年３月至１９９３年３月在鲁西和鲁南平原农作区对小型兽类群落进行了调查,其群落组成以啮齿动物为主,可划为６类群落：河滩高他的黑线仓鼠群落,河滩高地人房附近的黑线仓鼠＋小家鼠群落,缓平坡地的黑线仓鼠＋黑线姬鼠群落,浅平洼地的黑线姬鼠＋黑线仓鼠＋大仓鼠群落,洼地农作区的黑线仓鼠＋黑线姬鼠＋大仓鼠群落和洼地蔬菜种植区的黑线姬鼠＋黑线仓鼠群落。群落的季节变化明显,１１月至次年２月以黑线仓鼠为优势种,其它月份则黑线姬鼠或大仓鼠较多;人房附近农作区小家鼠也有季节性迁移现象。     

GENETIC ANALYSIS OF KILLER WHALE (ORCINUS ORCA) HISTORICAL BONE AND TOOTH SAMPLES TO IDENTIFY WESTERN U.S. ECOTYPES

Little is known about the historical range of killer whale ecotypes in the eastern North Pacific (ENP). It is possible that ranges have shifted in the last few decades because of changes in availability of food. In particular, the southern resident ecotype, currently found primarily in the inland waters of Washington State, is known to prey extensively on salmon, which have declined in recent decades along the outer coasts of Washington, Oregon, and California. To investigate historical distributions of this and the other ENP ecotypes, samples of teeth and bones were obtained from NMFS and museum collections. We amplified a short section of the mitochondrial DNA control region that contains four diagnostic sites that differentiate between haplotypes found in ecotypes of ENP killer whales. Results did not show any southern resident haplotypes in samples from south of the Washington State inland waterways. One whale genetically identified as a northern resident extends the known southernmost distribution of the population from Oregon to California. Items of diet identified from stomach contents of six of the whales genetically identified to ecotype conformed with what is known of the feeding habits of the various ecotypes.     

Comparison of conventional Papanicolaou smear and SurePath® liquid-based cytology in the Copenhagen population screening programme for cervical cancer

OBJECTIVE: To compare diagnostic performance of conventional Papanicolaou smear with SurePath liquid-based cytology in a population screening programme. METHODS: A retrospective comparison was performed on data from two 18-month periods of the screening programme for cervical cancer in the municipality of Copenhagen with conventional Papanicolaou technique (n = 82,116) and liquid-based cytology (n = 84,414). RESULTS: After the conversion to liquid-based cytology the percentage of unsatisfactory samples decreased from 2.3% to 0.3% (P < 0.001), whereas the number of normal cervical samples lacking an endocervical component increased from 8.5% to 8.9% (P < 0.005). The percentage of samples with atypical cells and cells suspicious for malignancy increased from 3% to 4.2% (P < 0.001) and from 1.9% to 2.4% (P < 0.001), respectively. The subsequent histological follow-up showed normal findings decreased from 70.5% to 68.9% and from 28.0% to 26.1%, respectively. However, in relation to the entire screening populations, there was an increase of normal findings from 2.12% to 2.89% after primary atypical diagnosis and from 0.53% to 0.62% after diagnosis of suspicious cells after conversion to the liquid-based technique. CONCLUSIONS: This study showed the number of unsatisfactory samples to be significantly reduced with the liquid-based technique. The data suggest that there is an increased detection rate of cervical precancerous lesions with liquid-based cytology, but the number of false positive tests is still high. The specificity of the two tests seems similar, but this cannot be ascertained exactly, because of the fact that follow-up of negative cases is unavailable.     

Drosophila mitochondrial DNA: Conserved sequences in the A+T-rich region and supporting evidence for a secondary structure model of the small ribosomal RNA

Summary The sequence of a segment of theDrosophila virilis mitochondrial DNA (mtDNA) molecule that contains the A+T-rich region, the small rRNA gene, the tRNA^f-met, tRNA^gln, and tRNA^ile genes, and portions of the ND2 and tRNA^val genes is presented and compared with the corresponding segment of theD. yakuba mtDNA molecule. The A+T-rich regions ofD. virilis andD. yakuba contain two correspondingly located sequences of 49 and 276/274 nucleotides that appear to have been conserved during evolution. In each species the replication origin of the mtDNA molecule is calculated to lie within a region that overlaps the larger conserved sequence, and within this overlap is found a potential hairpin structure. Substitutions between the larger conserved sequences of the A+T-rich regions, the small mt-rRNA genes, and the ND2 genes are biased in favor of transversions, 71–97% of which are AT changes. There is a 13.8 times higher frequency of nucleotide differences between the 5 halves than between the 3 halves of theD. virilis andD. yakuba small mt-rRNA genes. Considerations of the effects of observed substitutions and deletion/insertions on possible nucleotide pairing within the small mt-rRNA genes ofD. virilis andD. yakuba strongly support the secondary structure model for theDrosophila small mt-rRNA that we previously proposed.     

Molecular characterization of the rbcS multi-gene family of Petunia (Mitchell)

Summary The small subunit (RbcS) of ribulose bisphosphate carboxylase (RuBPCase) is encoded by eight genes in Petunia (Mitchell). These genes can be divided into three subfamilies (51, 117 and 71) based upon hybridization to three petunia rbcS cDNA clones. The nucleotide sequence of six of the eight petunia rbcS genes is presented here and the structure of the genes is discussed with respect to their genomic linkage and their expression levels in petunia leaf tissue. The rbcS genes belonging to the same subfamily encode an identical mature RbcS polypeptide, however the different subfamilies encode distinguishable polypeptides. All the genes, except one, contian two introns within the mature subunit coding region; one gene contains one extra intron within the coding region. There are large regions of nucleotide sequence homology within the introns of genes within a subfamily, but significantly less homology between the introns of genes of different subfamilies. A complex pattern of homology within the multiple genes of the 51 subfamily is observed. There are regions within these genes which share high levels of sequence homology; this homology does not extend throughout the whole gene and the regions of homology do not always occur in adjacent genes. Two 3 rbcS gene fragments which we isolated from the petunia genome show high levels of homology to two of the intact rbcS genes.     

Reference values for the concentrations of As,Cd, Co,Cr, Cu,Fe, I,Hg, Mn,Mo, Ni,Pb, Se,and Zn in selected human tissues and body fluids

This report attempts to formulate reference ranges of elemental concentrations for 15 trace elements in selected human tissues and body fluids. A set of samples consisting of whole blood, blood serum, urine, milk, liver, and hair were chosen and considered for 15 elements of biological significance: As, Cd, Co, Cr, Cu, F, Fe, I, Hg, Mn, Mo, Ni, Pb, Se, and Zn. The results represent wholly or partially data received from 40 countries of the global regions of Africa, Asia, Europe, North, South, and Central America, Australia, and New Zealand. This survey, even if qualitative, has been useful in demonstrating certain trends of trace-element scenarios around the world. It is of course recognized that both diet and environment exert a strong influence on the distribution pattern of several elements, such as As, Cd, Mn, Pb, Se, and Zn. A limited comparison of the available information on soil status of different countries reflected some interesting associations for elements, such as Mn and Zn. Importantly, this study revealed that only a few countries were in a position to identify a reasonable amount of data on samples requested for this project. Regretably, for a number of countries, any dependable data for even such essential elements as Cu, Fe, and Zn were not available. In view of the nutritional importance of many elements, the time is ripe for concerted efforts by intergovernmental agencies to initiate investigations or commission task forces/projects to generate reliable reference data for selected global regions, which sadly lack data of any kind at present.     

The importance of the transit peptide and the transported protein for protein import into chloroplasts

Summary We compared the transport in vitro of fusion proteins of neomycin phosphotransferase II (NPTII) with either the transit peptide of the small subunit (SSU) of ribulose-1,5-bisphosphate carboxylase/oxygenase or the transit peptide and the 23 aminoterminal amino acids of the mature small subunit. The results showed that the transit peptide is sufficient for import of NPTII. However, transport of the fusion protein consisting of the transit peptide linked directly to NPTII was very inefficient. In contrast, the fusion protein containing a part of the mature SSU was imported with an efficiency comparable to that of the authentic SSU precursor. We conclude from these results that other features of the precursor protein in addition to the transit peptide are important for transport into chloroplasts. In order to identify functional regions in the transit peptide, we analyzed the transport of mutant fusion proteins. We found that the transport of fusion proteins with large deletions in the aminoterminal, or central part was drastically reduced. In contrast, duplication of a part of the transit peptide led to a marked increase in transport.