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31.
Summary Earlier studies found that cotton (Gossypium hirsutum L.) cotyledons contain several mRNAs which are more abundant during late embryogenesis than in mid-embryogenesis or early germination. They are here termed Late embryogenesis-abundant mRNAs, encoded by Lea loci. Complementary DNA clones for 18 such mRNA sequences, defined at a hybridization criterion of Tm-15°C, were identified in a mature embryo cDNA library by differential cDNA hybridization. At a lower hybridization criterion, some sequence homology was found within several of these cloned Lea mRNA sequences. Each Lea mRNA sequence comprises 0.04–1.3% of mature embryo poly(A)+ mRNA, a level ten-fold to several hundred-fold higher than in young embryo or 24 h seedling poly(A)+ mRNA. Of 18 Lea mRNA sequences examined in cultured young embryos, the level of at least 13 are specifically increased by exogenous abscisic acid (ABA), several to a level near that in normal mature embryos. However, the abundance of several of the sequences does not appear to be significantly modulated by ABA. The LEA polypeptides encoded by 10 Lea mRNA sequences were identified by hybrid-arrested translation. They include most of the late embryogenesis-abundant, ABA-inducible, polypeptides previously identified. Preliminary results suggest that many of the individual Lea mRNA sequences are transcribed from 1–3 genes in each of cotton's two subgenomes. 相似文献
32.
Robert Puskas Natalie Fredd Celia Gazdar Alan Peterkofsky 《Archives of biochemistry and biophysics》1983,223(2):503-513
Under certain growth conditions, some strains of Escherichia coli accumulate toxic levels of methylglyoxal. This report characterizes a strain which synthesizes a mutant cAMP receptor protein in an adenylate cyclase deletion background. When cultured in glucose 6-phosphate minimal medium, this strain (222) was prematurely growth arrested due to methylglyoxal production; growth inhibition did not occur when the strain was grown in glucose minimal medium. A comparison of a variety of enzyme and cofactor levels in the related strains 222 (mutant) and 225 (wild-type) grown on either glucose or glucose 6-phosphate medium was carried out. The only difference found that might explain an increase in methylglyoxal accumulation was an elevated level of phosphofructokinase in strain 222 grown on glucose 6-phosphate. Since this enzyme activity probably limits hexose phosphate metabolism, it is suggested that growth inhibition in strain 222 may be due to increased production of triose phosphate, some of which is converted to methylglyoxal. 相似文献
33.
Mordechai Schreiber Leon Fogelfeld Miry C. Souroujon Fortune Kohen Sara Fuchs 《Life sciences》1983,33(15):1519-1526
Spiroperidol was covalently conjugated to bovine serum albumin (BSA). Conjugated spiroperidol was almost as efficient as free spiroperidol in its binding capacity to dopamine receptor. Antibodies to spiroperidol were produced in rabbits following repeated immunizations with the conjugate of spiroperidol and BSA. The obtained antibodies have an apparent KD of 0.02 nM for [3H]-spiroperidol. These antibodies bind also to other butyrophenones with IC50 values three to four orders of magnitude higher than the IC50 obtained with unlabeled spiroperidol. Antibodies were purified from anti-spiroperidol sera by affinity chromatography. Anti-idiotypic antibodies were raised in rabbits by immunization with the purified anti-spiroperidol antibodies. Some rabbits produced anti-idiotypic antibodies which bind to rat and calf striatum. 相似文献
34.
We have developed a method for enzymatic hydrolysis of both sulfated and glucuronidated catecholamines in plasma and red blood cell lysate. Hydrolysis occurs in the course of the radioenzymatic assay for catecholamines. In human plasma, catecholamines are conjugated almost entirely with sulfate while, in rat plasma, glucuronides are the main conjugates of epinephrine and dopamine but not norepinephrine. Rat plasma contains less percent conjugated catecholamine than human plasma. Human red blood cell lysate contains less conjugated catecholamine than plasma, whereas free E in lysate exceeds that of plasma and free NE has same level both in plasma and lysate. This method is useful in detecting total (free + sulfated + glucuronidated) catecholamines and the nature of conjugated catecholamines. 相似文献
35.
Rob J.M. Moormann Johan T. den Dunnen Leon Mulleners Peter Andreoli Hans Bloemendal John G.G. Schoenmakers 《Journal of molecular biology》1983,171(4):353-368
Two complementary DNA clones pRLγ-2 and pRLγ-3 of different rat lens γ-crystallin messenger RNAs have been used to identify γ-crystallin gene sequences in rat genomic DNA. Subsequently, the DNA present in the 18,000 to 20,000 bases region of the EcoRI digest, giving rise to a strong doublet hybridization signal, was cloned in λ phage Charon-4A. One of the clones, λRCHγ-3, carrying an insert of 17,500 bases has been characterized in detail. From analysis at the restriction enzyme level with 5′-, “middle” and 3′-specific subprobes of pRLγ-3 it could be deduced that λRCHγ-3 contains only one γ-crystallin gene. The coding sequences of this gene are interrupted by intronic DNA. The primary structure of this gene and its flanking regions have been established by sequencing the relevant regions of a subclone of λRCHγ-3, designated pRCHγ-3.1. The sequence data show that the γ-crystallin gene extends over 2700 bases of rat genomic DNA. The gene is split by two introns, one of 87 base-pairs after the third translation codon and a large one of 1880 base-pairs after codon 84. The mosaic structure of the gene is strictly co-linear with the structure of the γ-crystallin polypeptide in that the large intron is positioned in a region which specifies the so-called “connecting peptide” and which links the two highly symmetrical and homologous protein domains. Although expected from the cDNA and protein sequence no introns were observed between the coding regions in the DNA specifying the two homologous folding motifs present in each protein domain. The relevance of this phenomenon in terms of the evolution of the mature γ-crystallin gene is discussed. 相似文献
36.
Plant Molecular Biology - DNAs complementary to the mRNAs coding for the major cotton 48 kD and 52 kD storage proteins have been cloned and used to characterize the principal cotton storage protein... 相似文献
37.
B Leon A Shkolnik T Shkolnik 《Comparative biochemistry and physiology. A, Comparative physiology》1983,74(2):399-407
1. The Cape elephant shrew Elephantulus edwardi maintained a stable body temperature (37.6 C) over a wide range of ambient temperatures. 2. Normal eutherian mechanisms of temperature regulation were employed in the maintenance of homeothermy. 3. Water turnover rate and metabolic rate were lower than predicted for a similar-sized eutherian. 4. Maximal urine concentration was fairly high (3118 +/- 267 mOsm/kg) with urine osmolality largely dependent on the urea concentration. 5. Relative medullary thickness of the kidney (6.61 +/- 0.84) indicated a higher maximum urine concentration than found in the laboratory and reflected an arid habitat. 6. E. edwardi can be classed among the "advanced" homeotherms in view of the physiological adaptations employed for survival. 相似文献
38.
The Avoidance Response in Phycomyces 总被引:7,自引:1,他引:6
Phycomyces sporangiophores grow away from stationary objects, a phenomenon known as the avoidance response. Evidence is presented suggesting that a growth-stimulating gas is emitted from the sporangiophore and is then swept to the leeward side by air currents resulting in higher gas concentration on that side. The presence of a stationary barrier decreases the passive movement of the gas away from the leeward side. It is proposed that an increase of this gas on one side causes that side to grow faster. Indirect evidence suggests that the gas is water vapor. 相似文献
39.
Dissociation by Chelating Agents and Substructure of the Thermophilic Bacteriophage TP84 总被引:2,自引:1,他引:1
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The thermophilic bacteriophage TP84 is dissociated into its head, tail, and released deoxyribonucleic acid (DNA) by chelating agents such as ethylenediaminetetraacetic acid (EDTA) and phosphate. The phage is more sensitive to EDTA than to phosphate, and dialysis against either agent causes more effective dissociation than standing in their presence. The tail possesses a knobbed structure which is inserted into the head of the intact phage and to which the DNA appears to be attached. The method of dissociating TP84 described in this paper provides a source of undamaged structural components and intact strands of DNA for subsequent investigations. A possible mechanism of chelate inactivation is discussed. 相似文献
40.
The methodology and some of the requirements for the deoxyribonucleic acid-mediated transformation of an arginine auxotroph of Bacillus amyloliquefaciens to prototrophy are described. 相似文献