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1.
The biochemical system responsible for the bioluminescent flashing in a number of coelenterates has been isolated and partially characterized. The system involves a molecule termed a “photoprotein,” which emits a brief (1 second) flash of light when reacted with calcium. A chelating agent such as EDTA must be used at all times to maintain the activity intact. The activity of reacted photoprotein is not restored if the calcium is removed by EDTA.  相似文献   

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The benthic deep-water siphonophore Rhodalia miranda was collected for the first time in 1876 by H.M.S. Challenger off the Rio de la Plata estuary beneath the Subtropical Convergence at about 1000 m depth. Rhodalia was reported again about 100 years later from certain distant localities in the subantarctic region of the south-west Atlantic. Hydrographic and topographic features that may be involved in creating this peculiar distribution pattern are discussed together with a likely mode of dispersal of benthic coelenterates. The disjunct distribution of Rhodalia and other benthos of the upper Argentine Slope suggests the subsurface oceanographic régime to be quite different from what we know of the surface layers.  相似文献   

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A historical survey on so called "theory of totipotent interstitial cells (i-cells)" and analysis of modern notion concerning the system of stem i-cells (SSC) in hydra and some other Coelenterata, as well as its peculiar regularity, normal and at various restorative morphogeneses are presented. Morphogenesis and space organization of polyps do not depend on the SSC, just the reverse, the SSC characteristics -- probability of selfrenovation, the TC proportion differentiating in one or other direction -- are determined by the morphogenetic process. In hydra and hydroids a possibility of reversed differentiation of the TC, with a successive change of the differentiation program is demonstrated under certain experimental conditions.  相似文献   

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A new method of reproduction in Obelia   总被引:1,自引:0,他引:1  
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Gastrin/CCK-like immunoreactivity in the nervous system of coelenterates   总被引:2,自引:0,他引:2  
Using immunocytochemistry, gastrin/CCK-like immunoreactivity is found in sensory nerve cells in the ectoderm of the mouth region of hydra and in nerve cells in the endoderm of all body regions of the sea anemone tealia. These results are corroborated by radioimmunoassay: One hydra contains at least 5 fmole and one tealia at least 2 nmole gastrin/CCK-like immunoreactivity. Reactivities towards gastrin and CCK antisera with different specificities suggest that the coelenterate gastrin/CCK-like peptide contains the C-terminal amino-acid sequence common to mammalian gastrin and CCK. In addition the radioimmunochemical data indicate that the coelenterate peptide also contains an amino-acid sequence that resembles the sequence 20-30 of porcine CCK-33, but that no other sequences of gastrin are present. Thus, it is probably more CCK-like than gastrin-like.  相似文献   

12.
Summary Using immunocytochemistry, gastrin/CCK-like immunoreactivity is found in sensory nerve cells in the ectoderm of the mouth region of hydra and in nerve cells in the endoderm of all body regions of the sea anemone tealia. These results are corroborated by radioimmunoassay: One hydra contains at least 5 fmole and one tealia at least 2 nmole gastrin/CCK-like immunoreactivity. Reactivities towards gastrin and CCK antisera with different specificities suggest that the coelenterate gastrin/CCK-like peptide contains the C-terminal amino-acid sequence common to mammalian gastrin and CCK. In addition the radioimmunochemical data indicate that the coelenterate peptide also contains an amino-acid sequence that resembles the sequence 20–30 of porcine CCK-33, but that no other sequences of gastrin are present. Thus, it is probably more CCK-like than gastrin-like.  相似文献   

13.
水母雪莲细胞生物反应器悬浮培养   总被引:3,自引:0,他引:3  
《Acta Botanica Sinica》2000,42(1):98-101
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14.
Plasmid pBR322 DNA isolated from Salmonella typhimurium supX (topoisomerase I) mutants exhibits a novel supercoiling distribution characterized by extreme heterogeneity in linking number and the presence of highly negatively supercoiled topoisomers. The most negatively supercoiled topoisomers isolated from one supX mutant have more than twice the wild-type level of supercoiling; the distribution as a whole has a median superhelix density about 1.3 times that of wild type. Surprisingly, the supercoiling distribution of plasmid pUC9 DNA isolated from supX mutants differs from that of pBR322. Escherichia coli topoisomerase I mutants have been shown to acquire compensatory mutations that reduce bacterial chromosome supercoiling to below the wild-type level even in the absence of topoisomerase I. We find that such a compensatory mutation in an E. coli topoisomerase I deletion mutant does not reduce pBR322 DNA supercoiling to a level below that of wild type. Thus, the effects of topoisomerase mutations on supercoiling depend on the replicon.  相似文献   

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水母雪莲的幼根培养及植株再生   总被引:6,自引:0,他引:6  
1 植物名称 水母雪莲 (Saussureamedusa) ,藏药中称为恰羔素巴。2 材料类别 无菌苗的根。3 培养条件 诱导愈伤组织培养基以MS、C1 7或W 1 4为基本培养基 ,附加 2 ,4 D 1~ 2mg·L- 1 (单位下同 ) 肌醇 2 0 0 蔗糖 3% 琼脂 0 .5%。继代培养基为MS 2 ,4 D 1 肌醇 2 0 0 CH 30 0 蔗糖 3%~ 5% 琼脂 0 .5%。分化培养基配方为 1 /2MS KT 1 CH 30 0 肌醇 2 0 0 蔗糖 3% 琼脂0 .5% ,再附加 ( 1 )NAA 0 .5 6 BA 1或 ( 2 )NAA1 6 BA 2。所用培养基的 pH均调为 5.8。培养温度为…  相似文献   

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Starting in June 1983, 25 species of hermatypic corals, gorgonians, hydrocorals, anemones and zoanthids in the San Blas Islands, Panama, began showing signs of a loss of colour leading in some cases to a white bleached appearance. Histologic examination of six coral species indicated that bleaching was associated with drastic reductions in the density of zooxanthellae and with the atrophy and necrosis of the animal tissue. The severity of the bleaching varied among species and many species were unaffected. The species most extensively affected were: Agaricia spp., which became completely bleached and frequently died; Montastraea annularis which bleached and continued to survive; and Millepora spp. which bleached white but quickly regained their colouration. Shallow reefs dominated by Agaricia spp. suffered the most extensive bleaching. At one site, Pico Feo, 99% of the Agaricia (32% of the living cover) was bleached. On fore reers, which were dominated by Agaricia spp. and M. annularis, the proportion of M. annularis bleached ranged from 18 to 100% and that of Agaricia spp. from 30 to 53%. Transects at Sail Rock and House Reef were surveyed in August 1983 and January 1984. At those sites, 53% of the Agaricia cover died between August and January. The remaining living cover of Agaricia and of all other species exhibited normal colouration in January. Salinity and temperature were monitored every second day at 4 m depth between May 10 and August 28, 1983 at one of the localities. Bleaching was first observed within two weeks of a 2 °C rise in temperature which occurred in late May 1983. Temperatures remained at or above 31.5 °C for the following 3 weeks and were at or above 30 °C for an additional 4 weeks. The bleaching of corals in the San Blas was most likely due to those elevanted temperatures.  相似文献   

18.
Abundant FMRFamide immunoreactivity has been found in the nervous systems of all hydrozoan, anthozoan, scyphozoan and ctenophoran species that were looked upon. This general and abundant occurrence shows that FMRFamide-like material must play a crucial role in the functioning of primitive nervous systems.  相似文献   

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Guarente L 《Cell metabolism》2011,14(2):151-153
Protein acetylation now rivals phosphorylation in frequency of occurrence but is incompletely understood. A?picture is presented in which protein acetylation is linked to available energy via the NAD-dependent deacetylases. This model suggests that protein acetylation regulates metabolic strategy and also helps store energy in cells.  相似文献   

20.
Several tetracosapolyenoic acids (TPA) were detected in lipids of different marine coelenterates. Two of these acids were isolated and their structures were confirmed by chemical and spectral methods as all-cis-6,9,12,15,18-tetracosapentaenoic and all-cis-6,9,12,15,18,21-tetracosahexaenoic acid. Their distribution among lipids of a number of species of different classes of coelenterates from the northern and tropical seas, among neutral and polar lipids of these organisms was investigated. Significant quantities of TPA were found in all of the Octacorallia species studied. In some cases the sum of TPA reaches the level of 20% of total lipid fatty acids. The fatty acid composition of different coelenterates is also discussed.  相似文献   

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