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Abstract

The metabolism of 5-trifluro-2′-deoxythymidine (trifluridine; F3TdR) in male BALB/c mice bearing EMT-6 tumors has been investigated using 19F NMR spectroscopy. We previously (Tandon et al, 1992) reported the detection and identification of 5,6-dihydro-5-trifluorothymine (DHF3T, 3) and 5,6-dihydroxy-5-trifluorothymine (DOHF3T) as new metabolites of F3TdR in mice urine. Further exploration of the metabolism of trifluridine has led to the identification of α-trifluoromethyl-β-ureido-propionic acid (F3MUPA, 4) as a previously unreported metabolite in the urine of F3TdR treated mice. Authentic F3MUPA was obtained by synthesis via an established route. A comparison of chemical shift and the H-F coupling constant of an authentic sample, with the 19F signal from urine, indicated the presence of F3MUPA in murine urine. Mixing crude urine with authentic F3MUPA resulted in the enhancement of the corresponding fluorine signal without affecting or introducing others, thereby confirming the presence of F3MUPA as a urinary metabolite.  相似文献   

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The organization of neutral genetic variation has long been used as a diagnostic tool to infer demographic properties of populations, and recently it has been shown that this information can also be used to estimate the magnitude of genetic deterioration in small or fragmented populations. A further step of this research is to assess whether neutral genetic indicators can serve to predict and compare the viabilities of endangered species. I use modeling to explore how ecological metapopulation settings are related to neutral genetic indicators (such as the fixation index [F(ST)]), changes in genetic load, and metapopulation viability. The analysis indicates that genetic indicators are generally strongly and consistently correlated with the genetic load, population size and structure, and time of extinction but identifies two potential limitations for their use in viability assessments. First, the regime of environmental perturbations is not accurately reflected by neutral indicators, so that their predictive power may be reduced in variable environments. Second, many species are threatened by recent human-induced changes of their habitat configuration. In most cases, genetic indicators may not have reached their equilibrium value in the altered habitat, which limits their ability to compare species with heterogeneous histories and life-history traits.  相似文献   

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Sheng ML  Zeng XF 《ZooKeys》2010,(57):63-73
Four species of Mastrus Förster, 1869 are reported from China. Two, Mastrus nigrus Sheng & Zeng, sp. n. reared from Arge pullata (Zaddach) and Mastrus rugotergalis Sheng & Zeng, sp. n. reared from Diprion jingyuanensis Xiao & Zhang, are new to science. One, Mastrus deminuens (Hartig, 1838), is a parasitoid of Pachynematus itoi Okutani. A key to species of Mastrus Förster known in China is provided.  相似文献   

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The ultrastructure of the mature spore in four Japanese species of the acrocarpous moss genus Ptychomitrium is presented. In all species the spores have a similar pattern: there is no recognisable aperture nor sporoderm polarity, exine and perine are poorly developed, cytoplasm only occasionally shows polarity, and plastids have a well developed inner membrane system. The presence of frequent intine protrusions is a remarkable feature of this genus. A multilaminar structure of the exine, already observed in Grimmia, occurs also in these species although here it is less pronounced. The significance of these features is discussed within these species, as well as in comparison to other taxa, especially the genus Grimmia.  相似文献   

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栽培大麦,纤毛鹅观草,属间杂种,酯酶,过氧化物酶 ISOZYME ANALYSIS OF F5 AND BCiF4 FROM CULTIVATED BARLEY ( HORDEUM VULGARE ) ~ ROEGNERIA CILIARIS LI Wan-Ji LI Yi-Ping L1U Fang Abstract Esterase and peroxidase isozymes were analysed in the variants including 4 types, 16 lines of Fs, BC1F4 and the parents derived from cultivated barley ( Hordeum vulgare cv. Arupo) x Roegneria ciliaris (Trin.) Nevski in young roots, shoots, spikes and seeds. The zymogram patterns of esterase and peroxidase demonstrated that the 16 lines of F5 and BC1F4 had all or most bands of the cultivated barley parent cv. "Arupo", 1 to 3 bands from the male R. ciliaris, and new hybrid isozyme bands in various amount. Some bands of parent "Arupo" were lost. It suggested that the genetic substances come from R. ciliaris were stably inherited to the progenies of selfing and backcrossing, and there were some variations among the lines. There was certain relationship between isozyme variance and plant characters. Thus, in identifying the translocation lines by isozyme analysis, it would be preferable to study the various organ-specific isozymes or to trace one type of isozyme pattern in consequence.  相似文献   

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鲫鲤杂种一代(F1)自交二代(F2)的受精细胞学研究   总被引:1,自引:0,他引:1  
荷包红鲫(♀)×湘江野鲤(♂)杂交产生的杂种一代(F  相似文献   

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To investigate the possible effects of NZW genes on the class conversion of dsDNA-specific antibodies in NZB X NZW (B/W)F1 hybrids, we measured IgM, IgG1, and IgG2 dsDNA-specific antibodies, using the Crithidia luciliae kinetoplast immunofluorescence test, in NZB, NZW, B/W F1 hybrid, B/W F1 X NZB backcross, and B/W F1 X NZW backcross mice at 4, 7, and 10 months of age. The highest serum levels of IgM dsDNA-specific antibodies were observed in NZB mice at the ages tested; however, the amounts of IgG1 and IgG2 antibodies were scanty. In contrast, a large amount of both IgG1 and IgG2 dsDNA-specific antibodies was produced in B/W F1 hybrids, in which the serum IgM antibodies were lower than those observed in NZB mice. NZW mice were virtually negative for these antibodies. Progeny testing suggested that a combined effect of two unlinked dominant genes of the NZB strain determines the production of dsDNA-specific antibodies and that these genes only act to produce IgM antibodies. These traits are to a great degree modified by the NZW loci in B/W F1 hybrids, and a combined effect of two unlinked dominant genes leads to conversion of the class of the antibodies from IgM to IgG, which, in turn, increases the serum levels of dsDNA-specific antibodies. The F1 hybrid of C57BL/6 and NZW strains produced no dsDNA-specific antibodies, indicating that the relevant NZB predisposing genes are required for the NZW gene action. Linkage studies showed that one of such NZW genes is to some extent linked to the H-2 complex on chromosome 17, but not to Mup-1 (chromosome 4) or a coat color locus (chromosome 2). The appearance of IgG dsDNA-specific antibodies correlated well with the incidence of renal disease in B/W F1 X NZB backcross mice.  相似文献   

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S. F. Gray's Natural Arrangement of British Plants (2 vols., November 1821) was for many years deliberately and unjustly neglected by British botanists on account of its idiosyncrasies, anti-Linnaean character, unorthodox nomenclature, narrow generic concepts and contemporary hostility to the supposed authorR. A. Salisbury, but is nevertheless nomenclaturally important, particularly for cryptogamic groups. This paper surveys its history, authorship, date of publication and nomenclature.Dedicated to the memory of JohnS. L. Gilmour.  相似文献   

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M O'Regan  B Kiely  F O'Gara 《Gene》1989,83(2):243-249
To gain insight into the role of cyclic AMP (cAMP) in Gram-negative soil bacteria, we have studied the expression of an adenyl cyclase-encoding gene 'cya' of Rhizobium meliloti F34. In both Escherichia coli and Bradyrhizobium japonicum, the gene is expressed from a promoter(s) contained on a 2.6-kb fragment of the cloned insert, which may indicate the presence of a functional 'cya' promoter or the coincidental presence of sequences which can function as promoters in these two species. The study of 'cya'-lac fusion activity in R. meliloti indicated that the 'cya' gene is not expressed at detectable levels and, thus, may not contribute to the modulation of cAMP levels under the growth conditions employed. R. meliloti strains carrying defined genomic mutations at the 'cya' locus were still capable of the synthesis of near wild-type levels of cAMP. These results suggest that the cloned 'cya' gene is not the key determinant responsible for cAMP synthesis under the culture conditions employed.  相似文献   

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《Inorganica chimica acta》1989,156(2):251-256
The title compounds (1, X=F; 2, X=Cl) were obtained in quantitative yield by refluxing together (NBu4)2[Pd2(μ-Br)2(C6X5)4] and (NBu4)2[Pd2(μ-Br)2Br4]. Treatment of 1 or 2 with AgClO4 (Pd:Ag= 1:1) gave solutions which behaved as containing ‘Pd(C6X5)Br’. 1, 2 and the ‘Pd(C6X5)Br’ solutions were checked as precursors of mono-pentahalophenyl derivatives, yielding a variety of complexes [Pd(C6X5)Br(L-L)] (L-L=bipy, tmen, dpe, COD), [Pd(C6X5)BrL2] (L=p-TolNH2, py, PPh3, AsPh3, SbPh3), [Pd2(μ-Br)2(C6X5)2L2] (X=F, L=AsPh3; X=Cl, L=SbPh3) and (NBu4)[Pd(C6X5)Br2L] (X=F, L= py, AsPh3, SbPh3; X=Cl, L=p-TolNH2, py, PPh3, AsPh3, SbPh3). The solutions of ‘Pd(C6X5)Br’ proved to be the best general precursors of complexes [Pd(C6X5)BrL2] although complexes with OPPh3 could not be obtained.  相似文献   

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This paper addresses the question whether the pregnancy rate of dairy cows and heifers may be affected by administering prostaglandin F at the time of artificial insemination. A field trial involving 1031 dairy cows and heifers distributed to a large number of small dairy farms in an area of extensive farming in central Germany provided evidence that intramuscular administration of 25 mg Dinoprost (Dinolytic®) at the time of insemination has no effect on pregnancy rate (61% of the cows and heifers were pregnant in both prostaglandin F-treated and saline control groups). On the other hand, deposition of 0.5 mL of a 0.5 mg/mL Dinoprost solution in the uterine lumen immediately after artificial insemination gave rise to a pregnancy rate of 66% as compared with 59% in saline controls. The increase in pregnancy rate of 229 prostaglandin F-treated animals (66% pregnant) over that of 226 saline controls (59% pregnant) amounted to 12%. This improvement was not statistically significant (P = 0.12). Factors exerting a significant effect on pregnancy rate were parity (74% pregnancies in heifers versus 57% in cows, P < 0.01 and 65% pregnancies in first parity-cows versus 55% in older cows, P < 0.01) and season (57% during the barn season versus 64% during the pasture season, P < 0.05), whereas length of service period, level of milk production and serum or milk progesterone level at the time of insemination did not. A follow-up trial involving more animals will have to be conducted aimed at confirming the promising results obtained by intrauterine PGF administration.  相似文献   

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Summary Polyamines have been related to the Crassulacean Acid Metabolism (CAM) in higher plants. Such relationship was however observed in plants where CAM activity is inducible by external factors. Results presented here indicate that, inOpuntia F. indica, cladodes where onset of CAM is dependent on internal conditions, i.e. leaf age, the concentration of putrescine increases in parallel to the acidity of the cytoplasm. The parallel increase of putrescine concentration and acidity (malic acid concentration) can be best evaluated during the onset of CAM (young cladodes), while such correlation is not observed in mature cladodes where CAM is already in it's full function. Spermidine and spermine show no correlation with CAM activity neither during the onset of CAM nor during it's full function. However, spermidine levels correlate negatively to CAM activity when cladodes attain > 30 days of age. The results suggest that putrescine in free form could possibly counteract the increase of cellular acidity during onset of CAM inOpuntia F. indica; the possible roles of spermidine are discussed.Abbreviations PA polyamines - put putrescine - spd spermidine - spm spermine - HPLC high performance liquid chromatography This work was supported by grants from Italian Ministry of University and Scientific Research (60%).  相似文献   

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The reproductive morphology of Dumontia incrassata (O. F. Müller) Lamouroux is described from New Hampshire, U.S.A. populations. Mature carpogonial and auxiliary branches are usually 5 and 6 celled, respectively, but both may range from 4 to 9 cells. Auxiliary branches are more numerous than carpogonial branches; however, the ratio of carpogonial to auxiliary branches increases towards the apex of the frond. A linear relationship exists between the position of the generative auxiliary cell and the number of cells in the auxiliary branches. In most cases the third cell from the top of the auxiliary branch becomes the generative auxiliary cell. The probabilities for different positions of the generative auxiliary cells are summarized. During spermatangial development, four mother cells are initially produced per cortical cell initial; subsequently, successive spermatangia are cut off obliquely and on opposite sides of each mother cell. Monoecious asexual plants of D. incrassata are described, as well as an irregular tetraspore development.Scientific Contribution Number from the New Hampshire Agriculture Experiment Station; also issued as contribution No. 81 of the Jackson Estuarine LaboratoryScientific Contribution Number from the New Hampshire Agriculture Experiment Station; also issued as contribution No. 81 of the Jackson Estuarine Laboratory  相似文献   

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Indole alkaloids, oxytrofalcatins A–F (16), together with five other known alkaloids (711), were isolated from the roots of Oxytropis falcata. Their structures were elucidated by comprehensive spectroscopic analyses, including using 1D and 2D NMR spectroscopy and mass spectrometry. This is the first report of N-benzoylindoles from a natural source. Compounds 16 lacked significant cytotoxicity against SGC-7901 and HL-60 tumor cell lines.  相似文献   

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