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31.
The generation of long-lived microplasmoids is observed during the irradiation of a metal-dielectric surface with a high-power microwave beam in a chemically active gas mixture (H2 + O2; CH4 + O2). The lifetime of these plasmoids substantially exceeds the characteristic recombination and cooling times of plasmoids arising at the target surface in a chemically inactive medium.  相似文献   
32.
We report the identification of the first representative of the alpha-2-macroglobulin family identified in terrestrial invertebrates. An abundant acidic glycoprotein was isolated from the plasma of the soft tick Ornithodoros moubata. Its molecular mass is about 420 kDa in the native state, whereas in SDS/PAGE it migrates as one band of 190 kDa under nonreducing conditions and a band of 92 kDa when reduced. Chemical deglycosylation reveals that it is composed of two different subunits, designated A and B. The N-terminal amino-acid sequence of subunit A is similar to the N-terminus of invertebrate alpha-2-macroglobulin. Sequence analysis of several internal peptides confirms that the tick protein belongs to the alpha-2-macroglobulin family, and the protein is therefore referred to as tick alpha-macroglobulin (TAM). Functional analyses strengthen this assignment. TAM inhibits trypsin and thermolysin cleavage of the high-molecular-weight substrate azocoll in a manner similar to that of bovine alpha-2-macroglobulin. This effect is abolished by pre-treatment of TAM with methylamine. In the presence of TAM, trypsin is protected against active-site inhibition by soybean trypsin inhibitor. We cloned and sequenced a PCR product containing sequences from both subunits and spanning the N-terminus of subunit B and the putative 'bait region' (a segment of alpha-2-macroglobulin which serves as target for various proteases). This indicates that the two subunits are generated from a precursor polypeptide by post-translational processing.  相似文献   
33.
New genetic data with biotechnological potential (citrate metabolism, proteases, bacteriocin production) provides the genome sequence of the lactic acid producing bacterium of Enterococcus faecium strain 8S3, isolated from traditional Slovak cheese - bryndza produced from unpasteurised ewe milk. The genome sequence consists of 2.8 Mbp, with a mean G?+?C content of 38.2% and show high similarity to other E. faecium genome sequences. A total of 2.833 coding sequences, including 62 structural RNAs (3 rRNA and 59 tRNA) were predicted. Comparative genomic data indicate that prophages and bacteriophage remnants are the main source of diversity among E. faecium genomes.  相似文献   
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Although the faunal elements of Far East Asian Mesozoic terrestrial biota have attracted much attention in recent years, their palaeoecology remains poorly known. In particular, features of the palaeoclimate are highly controversial. To address this point we used the Mesozoic fossil wood Xenoxylon , a genus recognized as an indicator of wet temperate biotopes and which is common in the area during the Carnian–Maastrichtian interval. We re-appraised bibliographic data and gathered new data for Xenoxylon in the Mesozoic of Far East Asia. This demonstrated that previous taxonomic approaches to the genus have been so far idiosyncratic. We examined the anatomical diversity of morphogenus Xenoxylon in Far East Asia and compared it to that of samples from Europe. This indicates that in an area centred on north-eastern China, Xenoxylon reached a level of anatomical diversity unmatched elsewhere in the world. We hypothesize that this diversity witnesses the persistence of palaeoecological conditions particularly suitable for Xenoxylon and that a wet temperate climate prevailed over most of the area throughout the Carnian–Maastrichtian interval. It is in this setting that the famous Jehol Biota probably evolved.  相似文献   
38.
We have assigned all nine linkage groups of a Brassica oleracea genetic map to each of the nine chromosomes of the karyotype derived from mitotic metaphase spreads of the B. oleracea var. alboglabra line A12DHd using FISH. The majority of probes were BACs, with A12DHd DNA inserts, which give clear, reliable FISH signals. We have added nine markers to the existing integrated linkage map, distributed over six linkage groups. BACs were definitively assigned to linkage map positions through development of locus-specific PCR assays. Integration of the cytogenetic and genetic linkage maps was achieved with 22 probes representing 19 loci. Four chromosomes (2, 4, 7, and 9) are in the same orientation as their respective linkage groups (O4, O7, O8, and O6) whereas four chromosomes (1, 3, 5, and 8) and linkage groups (O3, O9, O2, and O1) are in the opposite orientation. The remaining chromosome (6) is probably in the opposite orientation. The cytogenetic map is an important resource for locating probes with unknown genetic map positions and is also being used to analyze the relationships between genetic and cytogenetic maps.  相似文献   
39.
A simple approach to a stable steroidal estrone derived A,B-spiro system is reported. Treatment of estrone derived A-ring diepoxyalcohol with the Ac2O–TMSOTf system at the ambient temperature led to acetylation, while at the reflux temperature the acid-catalysed rearrangement took place affording the spiro-compound. Results of extensive in vitro and in vivo anticancer tests on the diepoxide, as well as preliminary data on the antiproliferative activity of the spiro-product against three cancer cell lines, are also presented.  相似文献   
40.
Based on biological properties of epoxyquinols from natural sources, bromo and epoxyquinols derived from estrone were synthesized and screened against Fem-X, HeLa and K(562) cell lines. Evidence was found that the bromine atom and the epoxy moiety significantly increase the antiproliferative activity within the series.  相似文献   
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