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  • 1995-1999  (7)
  • 1970-1974  (5)
  • 1940-1944  (4)
  • Cell & Developmental Biology  (9)
  • mass spectrometry  (4)
  • gene expression  (3)
  • 1
    ISSN: 1573-5028
    Keywords: acetohydroxyacid synthase ; gene organization ; gene expression ; herbicide resistance ; cotton ; Gossypium hirsutum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The acetohydroxyacid synthase (AHAS) gene family of the cotton AD allotetraploid Gossypium hirsutum has been cloned and characterized. We have identified six different AHAS genes from an analysis of genomic clones and Southern blots of genomic DNA. Four of the six genes are organized as tandem pairs, in which the genes are separated by only 2–3 kb. Conservation of restriction fragment length polymorphisms between G. hirsutum and A-genome and D-genome-containing diploid cottons was sufficient to assign the single genes in clones A5 and A19 to the A and D subgenomes, respectively. Each diploid genome has one tandem pair, but in these cases we could not make specific subgenomic assignments. DNA and deduced amino acid sequences were determined for the A5 and A19 genes, and an AHAS cDNA clone isolated from a leaflibrary. The sequence of the A19 gene matches that of the cDNA clone, while the A5 gene is 97.8% similar. The four genes comprising the tandem pairs are much less similar to the cDNA clone. The deduced amino acid sequences of the mature polypeptides encoded by the A5 and A19 genes are collinear with the housekeeping forms of AHAS from Arabidopsis thaliana, Nicotiana tabacum and Brassica napus. The constitutive expression of A5 and A19 was confirmed with RNase protection assays and northern blots. We conclude that these genes encode the main house-keeping froms of AHAS in G. hirsutum. Among the four AHAS genes comprising the two tandem pairs, at least two are functional. These genes exhibit either low-level constitutive expression (one or both of the ‘downstream’ genes of each pair), or highly specific expression in reproductive tissue (one or both of the ‘upstream’ genes of each pair). The AHAS gene family of G. hirsutum is more complex than that of other plants so far examined.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5028
    Keywords: cotton ; gene expression ; Gossypium hirsutum ; metallothionein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have characterized cotton (Gossypium hirsutum L.) genes encoding type 1 metallothionein-like proteins that are highly expressed in roots. Little or no expression of these genes was detected in other organs and tissues. The deduced amino acid sequences have a high degree of similarity with type 1 metallothionein-like proteins from other plants, including a central hydrophobic domain flanked by conserved cysteine-rich motifs. The type 1 metallothionein-like genes of cotton are encoded by a small gene family. One gene (MT1-A) was analyzed in detail and found to have three exons which are 52, 83 and 397 bp long, and two introns 130 and 1042 bp in length. Three of the type 1 metallothionein-like genes are organized in a tandom array, and the 5′-flanking regions of these genes share a high degree of sequence similarity. Two of the clustered genes (MT1-A andMT1-B) are expressed at about equal levels in roots and use the same transcription start site. A 640 bp promoter fragment from theMT1-A gene was sufficient to direct expression of beta-glucuronidase (GUS) in transformed cotton roots. The expression was highest near the root tip.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5028
    Keywords: chitinase ; cotton ; gene expression ; 1,3-β-glucanase ; Gossypium hirsutum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated cDNA clones representing mRNAs encoding chitinase and 1,3-β-glucanase in cotton (Gossypium hirsutum L.) leaves. The chitinase clones were sequenced and found to encode a 28,806 Da protein with 71% amino acid sequence similarity to the SK2 chitinase from potato (Solanum tuberosum). The 1,3-β-glucanase clones encoded a 37,645 Da protein with 57.6% identity to a 1,3-β-glucanase from soybean (Glycine max). Northern blot analyses showed that chitinase mRNA is induced in plants treated with ethaphon or salicylic acid, whereas the levels of 1,3-β-glucanase mRNA are relatively unaffected. Southern blots of cotton genomic DNA and genomic clones indicated chitinase is encoded by a small gene family of which two members, Chi 2;1 and Chi 2;2, were characterized. These genes share 97% sequence identity in their transcribed regions. The genes were found to have three exons which are 309, 154 and 550 bp long, and two introns 99 and 154 bp in length. The 5′-flanking regions of Chi 2;1 and Chi 2;2 exhibit a large degree of similarity and may contain sequences important for gene response to chemical agents and fungal attack.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-904X
    Keywords: fluphenazine ; stable isotope ; deuterium labeled ; mass spectrometry ; schizophrenics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-1561
    Keywords: Alkaloids ; mass spectrometry ; infrared spectroscopy ; amphibians ; ants ; decahydroquinolines ; quinolizidines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three alkaloids—two minor decahydroquinolines (DHQs) and a major quinolizidine—were detected in an extract of a Brazilian myrmicine ant (Solenopsis (Diplorhoptrum) sp. picea group). One DHQ (3) was identical to a known frog-skin alkaloid, cis-195A (cis-5-methyl-2-propyldecahydroquinoline), while the second DHQ, an isomer of 3, designated 195J, was assigned a tentative cis-2-methyl-5-propyldecahydroquinoline structure (2) based on mass and infrared spectra. The third alkaloid proved identical to the frog-skin alkaloid 195C, for which a structure had not been previously proposed. Mass and infrared spectral analysis, including chemical ionization tandem mass spectrometry, indicated a 4-methyl-6-propylquinolizidine structure (1) for 195C. The four possible diastereomers were synthesized and the (6Z,10E)-4-methyl-6-propylquinolizidine diastereomer (1b) was identical to the natural alkaloid. Skin extracts of a population of a Madagascan mantelline frog contained, among other alkaloids, minor amounts of the same alkaloid triad 1–3 with 1 again predominating. The common occurrence of alkaloids 1–3 in both ant and frog supports the hypothesis that ants are a likely dietary source for sequestered frog-skin alkaloids and brings to six, the alkaloid classes common to ant and frog.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In muskellunge blastulae the yolk sac syncytium originally contains nuclei comparable in size to the blastomere nuclei from which the syncytial nuclei arose. By mitosis the originally diploid syncytial nuclei become numerous and crowded together. Continued synchronous mitosis of neighboring syncytial nuclei and the resultant crowding together of their spindles culminates in overlapping spindles, multipolar spindles, disorganized spindles, and the crowding together of large numbers of condensed chromosomes from contigous spindles. When such an aggregation of condensed chromosomes becomes enclosed within one nuclear membrane, a giant nucleus appears in the following interphase. It soon becomes postmitotic.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-904X
    Keywords: adinazolam mesylate ; gradient reversed-phase liquid chromatography ; mass spectrometry ; decomposition products assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A gradient high performance liquid chromatographic method was developed to determine degradation products of adinazolam mesylate in a sustained release tablet formulation. Sample preparations were chromatographed on a YMC-Basic column using a formate buffer/acetonitrile gradient with absorbance detection at 254 nm. Adinazolam mesylate was found to degrade at high relative humidity and temperature to form a major product, the 6-aminoquinoline analog, plus numerous other compounds. Five of these compounds were identified and their structures indicate that the solid-state degradation of adinazolam, in the presence of sufficient moisture, involves not only a hydrolytic mechanism, but also an oxidative mechanism. Potential process impurities were resolved from the drug and degradation products. Recovery was near 100% over the 0.5 to 10% range for the major degradate (6-aminoquinoline) and over the 0.5 to 1% range for the other analytes. The method was applied to tablet samples stressed at high relative humidity and temperature. The relative standard deviation of the assay for the 6-aminoquinoline was less than 2% and less than 13% for the minor components. Calculated mass balances (sum of adinazolam plus degradation products in the degraded tablet divided by the same sum in the undegraded tablet) were less than 100% and were dependent on the extent of degradation in the tablet. The average mass balance result obtained for samples that were an average of 9.5% degraded was 95.0 ± 1.5%. It is possible that the decrease in mass balance with increase in percent degradation may be explained by the formation of many components at trace levels due to degradation by various permutations of hydrolytic and oxidative reaction pathways.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 86 (1943), S. 15-39 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 86 (1943), S. 217-219 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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