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Glucose, and not trehalose, was found to be the main blood sugar inAplysia californica. Changes in blood glucose in response to stress produced by electric shock were measured in blood obtained both from animals dissected within ten minutes of shocking and from catheterized animals at various intervals, up to two and a half hours after the shock. Electric shock increased blood glucose levels. The rise in blood sugar continued as long as two and a half hours after shock. 相似文献
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Summary A bioassay was developed inHelix aspersa to study the effect of known endocrine centers on the twomonth-old gonad, using organ culture. The incorporation of14C leucine and3H fucose in the juvenile gonad almost doubled over control levels, in the presence of the brain and the dorsal bodies. 相似文献
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D. K. Srivastava S. S. Khanna V. M. S. Sriwastwa R. Kumar 《Cellular and molecular life sciences : CMLS》1985,41(5):603-605
Summary By electron diffraction pattern the presence of metallic elements, particularly chromium-nickel, chromium phosphide, copper, aluminum-copper and zinc has been shown in the pineal organ of a freshwater teleost,M. vittatus. It is likely that their occurrence within the pineal is due to binding with the neurosecretory material fractions/ligands.The technical assistance of O.N. Srivastava and financial assistance of CSIR, India, are gratefully acknowledged. 相似文献
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The mosaic pattern of double cones of retinas in larval and adult piranha,Serrasalmus spilopleura, was examined. Samples from two habitats in the same reservoir, characterized by different light conditions, were examined. The same square pattern was found in all sampled retinas indicating that, for this species, there is no apparent relation between the patterns of double cone arrangement and environmental luminosity. 相似文献
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Summary The proliferation of the mesenchyme of medium bud stage blastemas ofPleurodeles, measured by3H-thymidine incorporation and mitotic index, decreases about 40–50% under denervated conditions when cultivated in vitro for 4 days; epidermis is not affected in this case. Autoradiography of blastemas after3H-thymidine long term labeling shows that 3/4 of the mesenchymal cells and 1/4 of the epidermal cells are cycling when the blastema is innervated; there is no significant change of these percentages when the blastema is denervated. The results show, contrary to in vivo experiments, that denervation does not provoke an exiting from the cell-cycle but only lengthening of the cycle of the mesenchymal cells (probably of the G1 phase). 相似文献
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Summary It is reported that Ca2+-induced discharge of in situ nematocytes of acontia ofCalliactis parasitica can occur by cell-to-cell transmission along the acontial filament at a speed that averages 9.8·10–3 cm–1. The discharge is preceded by protrusion of nematocytes that proceeds along the acontium at a slightly higher speed. 相似文献
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A. Salleo G. La Spada M. Drago G. Curcio 《Cellular and molecular life sciences : CMLS》1994,50(2):148-152
On acontia ofCalliactis parasitica it was observed that mechanical stimuli applied by a gelatin probe, a method effective in tentacles of Anthozoa, do not induce the discharge of nematocytes. Hyposmotic shock, performed by treatment with NaCl solution 35% hyposmotic with respect to sea water, induces, in the presence of Ca2+, the discharge that spreads along the acontial filament, as previously observed following treatment with SCN–. The hyposmotic shock-induced discharge is blocked by Gd3+ at a concentration of 1 M. 10 M Gd3+ prevents also the SCN–-induced discharge. These results suggest the presence of stretch activated cation channels either in nematocytes and/or in supporting cells as well as a possible effect of SCN– on this class of ion channels. 相似文献
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Summary In vivo effects of epinephrine were investigated in a freshwater teleost,Barbus conchonius Hamilton. Fish given 2 mg/kg epinephrine in a single i.m. dose showed significant hypocholesterolemia and elevated, liver and kidney cholesterol levels 1–8 h postinjection. Plasma amino nitrogen evinced a transient yet significant fall at 2 h followed by a significant increase after 24 h. A marked reduction occurred in the plasma FFA and organic PO4 levels after 1–8 h. The results offer little evidence for a lipolytic effect of epinephrine in this species, and the changes in metabolite levels are attributable, in part, to the catecholamineinduced modification of insulin secretion.N.K. thanks the U.G.C. for the award of a research fellowship. 相似文献
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G. P. Wagner J. Lo R. Laine M. Almeder 《Cellular and molecular life sciences : CMLS》1993,49(4):317-319
Lectin binding, endo-chitinase binding and enzymatic degradation studies show that the epidermal cuticle of the bony fishParalipophrys trigloides (Blenniidae) is chitinous. This is the first evidence that a vertebrate species possesses a chitinous tissue. Recently aXenopus gene has been identified which has significant sequence similarity to the catalytic domain of yeast chitin synthase III, a chitin producing enzyme1,2. Taken together these two findings imply that chitin synthesis capability may be a basic vertebrate feature. 相似文献
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G. Cimino S. De Rosa S. De Stefano G. Sodano 《Cellular and molecular life sciences : CMLS》1985,41(10):1335-1336
Summary Polygodial (1), the defense metabolite stored in the skin of the nudibranchDendrodoris limbata, is toxic for the mollusc itself when injected into the hepatopancreas. Biosynthetic experiments using labeled mevalonic acid were devised to investigate a possible metabolic relationship between1 and the mixture of sesquiterpenoidic esters2, stored in the hepatopancreas. The results suggest that1 and2 are biosynthesized by independent pathways.Thanks are due to G. Villani for supplyingDendrodoris limbata and to A. Trabucco for technical assistance. 相似文献
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The amino acid histidine is an excellent buffer and is therefore included in several organ preservation solutions used in
transplantation medicine. However, when used at concentrations as in these solutions, histidine has a marked injurious potential.
Therefore, we here assessed the mechanism of histidine-induced cell injury and searched for ways to use the buffering power
of histidine but avoid histidine toxicity. When cultured hepatocytes were incubated in HTK solution or in modified Krebs-Henseleit
buffer containing 198 mM L-histidine at 37°C, most cells lost viability within 3 h (LDH release 86 ± 7% and 89 ± 5%, respectively).
This injury was accompanied by marked lipid peroxidation, and was strongly inhibited by hypoxia, by the antioxidants trolox,
butylated hydroxytoluene and N-acetylcysteine and by the membrane-permeable iron chelators 2,2′-dipyridyl, 1,10-phenanthroline, LK 614, LK 616 and deferoxamine.
Thus, histidine-induced cell injury appears to be mediated by an iron-dependent formation of reactive oxygen species. D-Histidine,
imidazol and L-histidine methyl ester also elicited marked injury, while the N-substituted derivatives Nα-acetyl-L-histidine and tert-butyl-oxycarbonylhistidine and histidine-containing dipeptides showed almost no toxicity. Histidine toxicity, its iron dependence
and the superiority of Nα-acetyl-L-histidine were also evident during/after cold (4°C) incubations. Therefore, we suggest the addition of iron chelators
to histidine-containing solutions, and/or replacing histidine with Nα-acetyl-L-histidine in organ preservation solutions.
Received 23 October 2006; accepted 21 November 2006 相似文献