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1.
Summary.  The paper describes two methods of the synthesis of ethyl (3R,4S)- and (3S,4S)-4-[(benzyloxycarbonyl)amino]-5-[(tert-butyloxycarbonyl)amino]-3-hydroxypentanoates, useful for the syntheses of edeine analogs. Differently N-protected (S)-2,3-diaminopropanoic acid was used as a substrate in both procedures. The absolute configuration of newly generated asymmetric carbon atoms C-3 in β-hydroxy-γ,δ-diamino products was assigned by means of 1H NMR spectroscopy after their transformation into corresponding piperidin-2-ones. Received May 24, 2002 Accepted October 10, 2002 Published online December 18, 2002 Acknowledgment The authors are indebted to the Faculty of Chemistry, Technical University of Gdańsk for financial support. Authors' address: Zbigniew Czajgucki, M. Sc., Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Technical University of Gdańsk, 11/12 Narutowicza St., 80-952 Gdańsk, Poland, Fax +48 58 347 11 44, E-mail: zmczaj@wp.pl  相似文献   

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There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes: Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed.  相似文献   

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Based on population analysis of the DRB1, DQA1, DQB1 and TNFA allele frequency distribution patterns, regional features of immunogenetic structure of the population of West Siberia were investigated. Statistically significant linkage disequilibrium within the HLA class II region, as well as between the TNFA and DRB1, DQA1, and DQB1 was demonstrated. Population frequency distribution patterns of two- and multilocus haplotypes were examined.  相似文献   

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We present data on the habitat, density, and spatial distribution of Rivulus giarettai, and discuss some biotic and abiotic variables related to its abundance in Free Flowing Waters (FFW) and Dam Reservoirs (DR) in palm grove (Mauritia flexuosa) marshes (Veredas) in Uberlandia, Minas Gerais, southeastern Brazil. The mean density (individuals/plot) of R. giarettai was about 13 times higher in FFW than in DR. In FFW, the density of R. giarettai was highest at intermediate amounts of substrate (plant mass) and it was positively rank-correlated with the depth, and the number of arthropods. Individuals occurred in an aggregated distribution. The aggregated pattern could be related to a concentration of individuals in microhabitats neither too much exposed nor completely saturated by plants. R. giarettai was relatively abundant and tolerant to slight man-made habitat modifications. Damming appeared to be especially problematic by negatively affecting its density.  相似文献   

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Boletus kermesinus, a new species of Boletus section Luridi, is fully described and illustrated based on the materials collected in subalpine coniferous forests of central Honshu, Japan. It has distinctive features of dark-red basidiomata having distinct viscidity in the pileus surface, usually unchanging flesh, discolorous red pores, and an entirely reticulate stipe becoming coarsely lacerate-rimose with age.  相似文献   

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Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this disease.  相似文献   

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The genus Cantharellus is known to have a global distribution and to form ectomycorrhizal associations with a diverse set of host plants. Here we describe Cantharellus pseudoformosus as a species new to science with a possible association with Cedrus deodara. ITS and LSU data demonstrated that the material from India is distinct from Cantharellus formosus and other closely related species.  相似文献   

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Summary  A new species of Eriocaulon, E. epedunculatum (Eriocaulaceae) is described and illustrated from the Western Ghats, India.  相似文献   

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A novel late embryogenesis abundant (LEA) gene (AY804193), namedCbLEA, has now been isolated fromChorispora bungeana. This rare alpine subnival plant can survive sudden snowstorms and low temperatures. The full-lengthCbLEA is 842 bp, with an open reading frame encoding 169 ami no acids. The putative molecular weight ofCbLEA protein is 17.9 kDa, with an estimatedpl of 6.45. To investigate the functioning of thisCbLEA protein in cold-stress tolerance,CbLEA was introduced into tobacco under the control of the CaMV35S promoter. Second-generation (R1) transgenic tobacco plants exhibited significantly increased tolerance to cold. These transgenics maintained lower malondialdehyde (MDA) contents and electrolyte leakage (EL) but their relative water content (RWC) was significantly higher compared with non-transgenic plants under chilling stress. Further experimental results showed that non-transgenic plants had severe freezing damage after exposure to -2°C for 1 h, whereas the transgenics suffered only slight injury under the same conditions. Moreover, survival was longer in the latter genotype at that temperature. The extent of increased cold tolerance was positive correlated with the level ofCbLEA protein accumulation, and was also reflected by the delayed development of damage symptoms. This indicates thatCbLEA is an excellent stress tolerance gene, and holds considerable potential as a new molecular tool for engineering improved plant genetics.  相似文献   

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A new species of Lamiaceae from Belize: Hyptis maya is described and illustrated. It is closely related to the more widespread H. lanceolata Poir., with which it is compared.  相似文献   

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Glycoprotein IIb/IIIa complex, a platelet surface fibrinogen receptor, plays a key role in producing primary hemostasis. At present, only a single mutation in the GPIIIa gene, Leu33Pro, and a single mutation in the GPIIb gene, Ile843Ser, has been described. The mutations are known to enhance signaling functions of the receptor and are associated with the development of arterial thromboses. In the present study, we describe a novel GPIIIa mutation, which is T to G nucleotide substitution in position 1585, resulting in the replacement of Leu for Arg in position 40 of the amino acid sequence of the protein.__________Translated from Genetika, Vol. 41, No. 6, 2005, pp. 838–843.Original Russian Text Copyright © 2005 by Sirotkina, Shaydina, Vavilova, Schwartz.  相似文献   

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Maireina afibulata and M. attenuatipilis are proposed as new members of the recently revised genus Maireina, one of the few anatomically well-studied cyphelloid groups in the Basidiomycota. Maireina species have brownish basidiomes, smooth, parietally unpigmented spores, and are characterized by non-ramified external hyphae with more or less thick, yellow to brown cell walls and distinct crystalline incrustations that always include their distal ends. A key to the species of the genus Maireina is presented, and M. afibulata as well as M. attenuatipilis are described and discussed in detail. Taxonomic novelties: Maireina afibulata Bodensteiner, M. attenuatipilis Bodensteiner  相似文献   

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An autolysin gene, atlh, was identified and sequenced from Streptococcus downei MFe28 using degenerate polymerase chain reaction (PCR) and the gene-walking method. Atlh protein encoded by atlh is composed of 879 amino acids, with a molecular weight of 95,902.26. Atlh possesses four 15-amino-acid residue repeats in the putative cell-wall-binding domain and has a catalytic domain in the C-terminus. The deduced amino acid sequence of atlh showed homology to S. mutans autolysin AtlA (68.4% similarity). Inactivation of atlh resulted in elongated chain formation compared to the parent strain. Recombinant proteins Atlh and its derivatives were constructed and analyzed by zymography. Zymographic analysis revealed that the Asp-771 residue of Atlh was essential for lytic activity and that lytic activity was not diminished by the deletion of repetitive regions in the putative cell-wall-binding domain of Atlh. Biofilm assay showed that the wild-type strain formed glucose- and sucrose-dependent biofilms, the atlh mutant diminished this ability. These results suggest that Atlh is associated with cell separation and biofilm formation.  相似文献   

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