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191.
Sucrose, supplied to detached pea (Pisum sativum L. var Alaska) epicotyls through cut bases, supported better growth of apical tissue than supplied glucose and/or fructose. The hexoses were converted mainly to sucrose in basal regions of the epicotyl but some moved as such through the epicotyl and accumulated at the apex (plumule) at a rate faster than sucrose. A greater proportion of the carbon derived from supplied hexoses than from sucrose was used for synthesis of ethanol-insoluble products throughout the epicotyl. By use of asymmetrically labeled sucrose, it was shown that neither hexose moiety was used preferentially for the synthesis of metabolites. Supplied sucrose moved as such only up to the region of cell elongation where it was hydrolyzed and completely equilibrated before moving into more apical regions. The results indicate that better growth with supplied sucrose than hexose could not have resulted from differential effects on cell division, more rapid uptake or transport of sucrose, enhanced wall synthesis, or cleavage by sucrose synthase. It is concluded that transported sucrose versus hexoses must undergo or evoke different reactions which affect growth in the region of cell elongation.  相似文献   
192.
The syntheses of (±) 2α,6β-diethyl-7α-ethynyl-3α-(p-hydroxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (8), (±)2β,6β-diethyl-7α-ethynyl-3β-(p-methoxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (12) and (±) 2α,6β-diethyl-7α-ethynyl-3β-(p-hydroxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (18) and their derivatives, which are essentially B-seco-steroids having cis-anti-trans, cis-syn-trans and trans-anti-trans geometries have been carried out. A study of their antiimplantation activities (AI) and receptor binding affinities (RBA) show that trans-anti-trans compounds are biologically most potent, followed by the corresponding cis-anti-trans and cis-syn-trans compounds. The most potent compound 18 is active at 1 mg/kg in rats. Introduction of 7α-ethynyl group increases their AI activity; however, no significant effect on their RBA is observed.  相似文献   
193.
Changes in activity levels of important enzymes of carbohydratemetabolism (and ß-amylases, sucrose synthetase, acidinvertase, acid phosphatase, glucose phosphate isomerase, aldolase,phosphofructokinase and pyruvate kinase) during seed developmentwere determined. Changes in the activities of these enzymesand their functional significance in developing seeds are described.A close correlation was found between the stage of maximum carbohydrateoxidation and the accumulation of reserve materials in the developingseeds. 1Present address: School of Agriculture and Forestry, Universityof Melbourne, Parkvilie 3052, Victoria, Australia. 2Present address: School of Botany, University of Melbourne,Parkville 3052, Victoria, Australia. (Received October 8, 1982; Accepted January 10, 1983)  相似文献   
194.
Injection of folic acid (FA) into the nucleus substantia innominata (NSI) was found to decrease [3H]quinuclidinyl benzilate ([3H]QNB) binding in the frontal cortex, pyriform cortex, amygdala, and the NSI itself without changing the KD. Binding in the thalamus, caudate nucleus, hippocampus, and substantia nigra was not affected. [3H]Flunitrazepam binding was unchanged in all eight regions studied. Previous work indicates FA injections into the NSI produce epileptiform activity and cause loss of GABAergic and possibly other neurons in the frontal and pyriform cortices, the amygdala, and thalamus. The reductions of [3H]QNB binding in the first three of these regions are interpreted as indicating that many of the neurons lost are cholinoceptive, a finding that supports the previous hypothesis that activation of cholinergic projections from the NSI is an important part of the mechanism of cell loss in these regions.  相似文献   
195.
A total of 24 uterine biopsies were successfully obtained from 40 repeat-breeding buffaloes. The endometrium of 15 buffaloes showed marked neutrophilic infiltration in the epithelium, stroma and uterine glands. In some cases, lymphocyte and plasma cell infiltration, cystic dilatation of the glands and periglandular fibrosis indicated chronicity of the endometritis. Most of the animals (85.0%) had uterine cultures positive for Streptococci, Staphylococci, Gram positive variable cocci, Gram negative bacilli, Anthracoids, and Gram positive bacilli with a predominance of Corynebacteria. With the treatment based on in vitro drug sensitivity tests, 57.1% repeat-breeding buffaloes conceived.  相似文献   
196.
The amino acid and ammonia profiles in various tissues of the rat exposed to different pressures of pure oxygen have been studied. Well-defined changes in behavioral activity accompanied a profile of increasing pressure, culminating in convulsive activity in each group of exposed animals. After an initial depression of ammonia, in all tissues studied at 0.68 atm oxygen ammonia increased significantly at higher oxygen pressures. A rise in tissue ammonia took place in the absence of undue muscular activity on the part of the exposed animals. A significant increase in ammonia occurred first in brain and liver at 3.40 atm. Ammonia concentration was high in all tissues after convulsions occurred at 4.08 atm. Between 0.68 and 2.72 atm oxygen, tissue ammonia concentration was generally low and brain glutamate and gamma-aminobutyric acid were high. At pressures higher than 2.72 atm oxygen, tissue glutamate declined and glutamine increased. Alanine became significantly elevated in serum and muscle at high oxygen pressure, and aspartate was depressed in heart, liver, and muscle. These pressure-course experiments on ammonia accumulation in tissue confirm previous serial time course observations that ammonia accumulates in the brain and several tissues of the rat even in the absence of undue muscular activity during high-pressure oxygen exposure and is a significant factor in inducing convulsions.  相似文献   
197.
Two genes, MF alpha 1 and MF alpha 2, coding for the alpha-factor in yeast Saccharomyces cerevisiae were identified by in situ colony hybridization of synthetic probes to a yeast genomic library. The probes were designed on the basis of the known amino acid sequence of the tridecapeptide alpha-pheromone. The nucleotide sequence revealed that the two genes, though similar in their overall structure, differ from each other in several striking ways. MF alpha 1 gene contains 4 copies of the coding sequence for the alpha-factor, which are separated by 24 nucleotides encoding the octapeptide Lys-Arg-Glu-Ala-Glu(or Asp)-Ala-Glu-Ala. The first alpha-factor coding block is preceded by a sequence for the hexapeptide Lys-Arg-Glu-Ala and 83 additional amino acids. MF alpha 2 gene contains coding sequences for two copies of the alpha-factor that differ from each other and from alpha-factor encoded by MF alpha 1 gene by a Gln leads to Asn and a Lys leads to Arg substitution. The first copy of the alpha-factor is preceded by a sequence coding for 87 amino acids which ends with Lys-Arg-Glu-Ala-Val-Ala-Asp-Ala. The coding blocks of the two copies of the pheromone are separated by the sequence for Lys-Arg-Glu-Ala-Asn-Ala-Asp-Ala. Thus, the alpha-factor can be derived from 2 different precursor proteins of 165 and 120 amino acids containing, respectively, 4 and 2 copies of the pheromone.  相似文献   
198.
Development of Newcastle disease, after experimental and natural infection with the virulent strain VLT of Newcastle disease virus, and its growth and distribution in some selected tissues as assayed by the enumeration of plaques are reported.  相似文献   
199.
200.
Summary Surveys for polymorphisms in natural populations of A. barbata sampled in California grasslands had provided evidence for widespread monomorphism and rather localized polymorphic areas in the north coastal and San Francisco regions, based on a set of morphological and isoenzymatic marker loci. Since this species, like many other annuals, was introduced from the Mediterranean region during the Spanish mission period, a comparative study of the Canadian-Welsh collections of Avena species from the Mediterranean region was undertaken using various plant characters and starch gel electrophoresis to analyze variants for esterase, phosphatase and peroxidase systems. A total of 96 samples including 73 of A. barbata and 23 of A. hirtula were studied and the results were scored to compute the polymorphism indices. In both species, only 10 to 15 percent sites showed any significant degree of polymorphism of which a majority seemed to originate from localized regions in Italy and Turkey; a part of this observed lack of within-sample variation might be the result of small sample size. In general, the patterns of variation in A. barbata from the California surveys and the present analyses seemed to be very similar and raised some interesting questions on (a) the colonizing history of introduced materials (b) the factors underlying such marked patterns of geographical variation, and (c) the current evolutionary changes occurring in these two broad, disjunct areas of species distribution.
Zusammenfassung Untersuchungen der Polymorphismen in natürlichen Populationen von A. barbata im kalifornischen Weideland hatten einerseits zum Nachweis eines weit verbreiteten Monomorphismus und andererseits streng lokalisierter polymorpher Bereiche in der nördlichen Küsten- und San Francisco-Region geführt, wobei eine Anzahl morphologischer und isoenzymatischer Markerloci zugrunde gelegt wurde. Da diese Art, wie viele andere Annuelle auch, während der spanischen Missionsperiode aus der Mittelmeerregion eingeführt wurde, wurde eine vergleichende Untersuchung der Canadian-Welsh-Sammlungen von Avena-Arten aus der Mittelmeerregion anhand verschiedener Merkmale der Pflanzen und der Stärkegelelektrophorese-Untersuchung auf Esterase-, Phosphatase- und Peroxydase-Systeme durchgeführt. Es wurde eine Gesamtheit von 96 Stichproben, bestehend aus 73 A. barbata und 23 A. hirtula, untersucht und die Ergebnisse zur Berechnung von Polymorphismus-Indices verwendet. In beiden Arten zeigten nur 10 bis 15% der Herkünfte einen signifikanten Polymorphismusgrad. Von ihnen scheint die Mehrzahl von lokalisierten Regionen in Italien und Griechenland abzustammen. Ein Teil des beobachteten Fehlens einer Variation innerhalb der Stichproben könnte eine Folge des geringen Stichprobenumfangs sein. Im allgemeinen scheinen die Variationsmuster der kalifornischen Untersuchungen und die der vorliegenden Analysen von A. barbata sehr ähnlich zu sein. Das führt zu einigen interessanten Fragen nach a) der Besiedelungsgeschichte des eingeführten Materials, b) den Faktoren, die derart auffallenden Mustern der geographischen Variation unterliegen und c) den laufenden evolutionären Änderungen, die in diesen beiden großen, voneinander getrennten Gebieten der Artverteilung auftreten.


This work was supported in part by a grant from the National Science Foundation (GB 8627).  相似文献   
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