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41.
2 O2 when the brown scales were suspended in water. Brown components isolated from the brown scales also transformed molecular
oxygen into H2O2. During the autooxidation process, absorbance in the visible region was increased. On acid hydrolysis of the brown fraction,
2,4,6-trihydroxyphenylglyoxylic acid, 3,4-dihydroxybenzoic acid and the quinone form of benzoic acid were detected. In addition,
glucose was detected as a sugar. 3,4-Dihydroxybenzoic acid was preferentially oxidized during autooxidation of the brown fraction.
One of the oxidation products was the quinone form. Stable electron spin resonance (ESR) signals were detected in the brown
fraction. New ESR signals appeared on oxidation of the brown fraction by hexacyanoferrate (III). One of the newly formed radicals
seemed to have a 3,4-dihydroxyphenyl group. Based on these results, possible structures, mechanism of H2O2 formation and biological significance of the brown components are discussed.
Received 11 April 2001/ Accepted in revised form 3 August 2001 相似文献
42.
Two experiments were carried out to test whether cells which are born in adulthood and migrate to the olfactory bulb of adult male golden hamsters are activated during sexual behaviors, to determine the time course over which such responsiveness appears, and to ask whether activation is specific to sexual cues. In the first experiment, adult male hamsters were injected with 5'-bromodeoxyuridine (BrdU, 50mg/kg b.w.) 3 times over the course of one week in order to mark dividing cells. Ten days, three weeks, or seven weeks after the first BrdU injection, the animals were allowed to mate with an estrous female for half an hour before being sacrificed. Confocal analysis of fluorescent immunostaining of BrdU and c-Fos first revealed dual labeled cells in the olfactory bulb 3 weeks after injection of the thymidine analog. In order to determine whether the activation of these newly generated cells is specific to sexual cues, we next compared the incidence of c-Fos expression in newborn (BrdU positive) cells among male hamsters exposed to an estrous female, an aggressive male, a cotton swab containing vaginal secretion from an estrous female hamster (FHVS), a cotton swab containing peppermint, or a cotton swab containing distilled water. In the mitral and glomerular layers of the accessory olfactory bulb, animals exposed to an estrous female had significantly more double labeled cells than did those given other treatments (p < 0.01). In the mitral layer of the main bulb, animals exposed to an estrous female had a significantly higher percentage of double labeled cells than those of other groups, except those exposed to an aggressive male (p < 0.05). No double labeled cells were seen in medial preoptic area (MPOA), medial nucleus of the amygdala (Me), the bed nucleus of the stria terminalis (BNST), or the hypothalamus. Our results indicate that cells born in adulthood are more responsive to cues arising from estrous females than other stimuli, and thus may participate in sociosexual behaviors. 相似文献
43.
Acosta GB 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2001,128(1):11-17
Cholecystokinin sulfated octapeptide (CCK-8S) was given to rats i.p. at single doses of 10 and 100 nmol/kg, respectively. It produced a modification in GABA levels in several areas of the rat brain. After 30 min of injection, the lower dose (10 nmol/kg) increased GABA levels in striatum by 31% (P<0.05). The higher dose (100 nmol/kg) enhanced GABA levels either in hippocampus by 78% (P<0.05) or in frontal cerebral cortex by 81% (P<0.05) and decreased in olfactory bulbs by 57% (P<0.01). Thus, these results show that systemic injection of CCK-8S, produced regional specific changes on GABA levels in brain, and these effects were dose-dependent. Systemic pretreatment with the CCK(B) receptor antagonist, PD 135,158, 1 mg/kg i.p., on the endogenous levels of GABA in certain regions was also studied. The selective CCK(B) receptor antagonist, PD 135,158, did not have an effect per se on the endogenous levels of GABA but prevents the action induced by the neuropeptide. We suggest that the action of CCK may be mediated via a selective action on the CCK(B) receptor subtypes. 相似文献
44.
Friable callus was obtained from styles and flower pedicels of Lilium longiflorum Snow Queen and the Oriental lily hybrid Star Gazer on Murashige and Skoog (MS) media containing either 2 μm dicamba or 2 μm picloram. Cell suspension cultures were established by suspending the callus of L. longiflorum Snow Queen in liquid medium containing 2 μm dicamba. Through a purification process, a fine fast-growing cell suspension was obtained. This suspension was composed of
a homogenous population of small dense cells, which tended to organise into embryo like structures (ELS). In liquid culture
with the auxin dicamba, the ELS underwent continuous callus formation. When transferred to solidified hormone-free MS medium,
the ELS germinated, forming complete plantlets. Histological investigation showed that in the ELS both shoot and root meristems
were distinctly evident. It was concluded that the ELS obtained were in fact somatic embryos.
Received: 4 April 1997 / Revision received: 13 May 1997 / Accepted: 15 June 1997 相似文献
45.
David T. Coxon Timothy M. ONeill John W. Mansfield Alexander E.A. Porter 《Phytochemistry》1980,19(5):889-891
Three phytoalexins were isolated from daffodil bulb scales inoculated with Botrytis cinerea and identified as 7-hydroxyflavan, 7,4′-dihydroxyflavan and 7,4′-dihydroxy-8-methylflavan. The structures of the phytoalexins were confirmed by total synthesis. 相似文献
46.
Dr. Kenichi Takaya 《Cell and tissue research》1977,178(2):169-173
Summary Electron microscopy of unstained, fresh air-dried spreads of plucked human hair bulbs revealed relatively well preserved melanocytes and dense storage granules of melanin. Energy dispersive X-ray microanalysis of melanosomes and premelanosomes from black facial hair bulbs disclosed high peaks for potassium and sulfur, intermediate peaks for magnesium and calcium, and low but distinct ones for phosphorus and chlorine. No peaks for magnesium were found in the central portion of mature melanosomes, but at their edges and in premelanosomes conspicuous peaks for this element were obtained.Supported by a grant from the Ministry of Education of JapanThe author thanks Dr. H. Fujita for his advice and Messrs K. Yonehara, S. Okamura, T. Fukuoka, and T. Asai, Naka Works, Hitachi Ltd., Katsuta, Ibaraki, for use of their X-ray microanalyzer and for their assistance in electron probe analysis 相似文献
47.
An overview of the Cape geophytes 总被引:1,自引:0,他引:1
ERBAN PROCHE RICHARD M. COWLING PETER GOLDBLATT JOHN C. MANNING DEIRDRÉ A. SNIJMAN 《Biological journal of the Linnean Society. Linnean Society of London》2006,87(1):27-43
The Cape Region (here treated as the winter rainfall region of southern Africa, thus including fynbos, renosterveld and succulent karoo vegetation) is the world's foremost centre of geophyte diversity. Some 2100 species in 20 families have been recorded from this area, 84% of them endemic. The most important families, with more than a hundred geophyte species each, are Iridaceae, Oxalidaceae, Hyacinthaceae, Orchidaceae, Amaryllidaceae and Asphodelaceae. Although southern Africa does not appear to have been the main diversification centre for the plant orders with highest geophyte representation (Asparagales and Liliales), it represents an active centre of transition to geophytism, such transitions having occurred independently in numerous plant groups, often followed by rapid speciation. Several Cape geophyte groups have consequently expanded across Africa to the Mediterranean Basin, and possibly to other winter rainfall regions. Remarkably high local species diversity in renosterveld vegetation, even in relatively homogeneous environments, suggests that pollinator specificity and phenology play an important role in niche partitioning. However, character diversity is also high in storage organs and leaves, and this could account for the high species diversity values recorded at larger spatial scales, especially across environmental gradients. Long-term climatic stability, combined with topoclimatic and edaphic diversity and regular fire occurrence, is likely to be responsible for the remarkable geophyte diversity of the Cape, as compared to other mediterranean-climate regions. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 27–43. 相似文献
48.
Shibnath Ghosal Potharaju H. Rao Dinesh K. Jaiswal Yatendra Kumar August W. Frahm 《Phytochemistry》1981,20(8):2003-2007
From the bulbs of Crinum pratense, collected at flowering, lycorine, 1,2-diacetyllycorine, ambelline, narcissidine, and three phenanthridone alkaloids, viz. hippadine, pratorinine and anhydrolycorin-7-one, were isolated and characterized on the basis of comprehensive spectral analyses (UV, IR, 1H NMR, 13C NMR, MS, [α]D) and chemical evidence. Among the phenanthridone alkaloids (1–3, only the natural occurrence of hippadine was previously known. Pratorinine is a new phenanthridone alkaloid and anhydrolycorin-7-one was known before only as a synthetic compound. The physiological significance of hippadine is appraised. 相似文献