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Shinya Matsuda 《Coral reefs (Online)》1989,7(4):185-195
Observations were made on the succession and growth rates of crustose coralline algae growing in situ on artificial substrata in a shallow fore-reef environment on Ishigaki Island, Ryukyu Islands. Succession in well-illuminated environments manifests itself as a gradual replacement of species having very thin thalli by those having larger and thicker thalli. The species Porolithon onkodes, Paragoniolithon conicum and Lithophyllum insipidum achieved dominance by competitive interactions of overgrowing margins. The thicker species recruit quickly (within the first few months), but because of their slow growth rate do not displace the pioneer species that have very thin thalli until after the latter begin to die. Regardless of seasonal temperature fluctuations, which exceed 10 °C, the coralline algal succession is the same for each season. The maximum lateral growth rates of the major species range between 2.9 and 3.9 mm/month. Vertical growth rates of Porolithon onkodes, the thickest species, are the most rapid (more than 2 mm/year at maximum) relative to those of other species. Accretion rates of entire coralline algal cover on ungrazed substrata range from 1.0 to 1.2 mm/year (not allowing any lag time for recruitment), whereas those of grazed substrata are lower. These results are consistent with species which are ecological equivalents and live in similar environments on Caribbean reefs. 相似文献
106.
L V Natochin YuVReznik V T Bakhteeva E M Myazina V K Brovtsyn 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1989,94(1):115-120
1. The kidney of frog and black sculpin appeared to be much less sensitive to the toxic action of CP in comparison with rat and pigeon. 2. The impairment of renal function after CP administration resulted in increased serum urea in rat, uric acid in pigeon and magnesium in black sculpin. 3. Kidney swelling is important feature of CP nephrotoxicity in rat and pigeon but not in frog and fish. 4. Pretreatment with choline chloride, PAH, furosemide and ethacrynic acid reduced the nephrotoxic action of CP in rat but did not prevent the accumulation of platinum in renal tissue which appeared to be a function of the dose injected to investigated animals. 相似文献
107.
P A Pevzner A A Borodovsky MYuMironov 《Journal of biomolecular structure & dynamics》1989,6(5):1013-1026
Mathematical models of the generation of genetic texts appeared simultaneously with the first sequencing DNA. They are used to establish functional and evolutionary relations between genetic texts, to predict the number and distribution of specific sites in a sequence and to identify "meaningful" words. The present paper deals with two problems: 1) The significance of deviations from the mean statistical characteristics in a genetic text. Anyone who has addressed himself to the statistical analysis of sequenced DNA is familiar with the question: what deviations from the expected frequencies of occurrence of particular words testify to the "biological" significance of those words? We propose a formula for the variance of the number of word's occurrences in the text, with allowance for word overlaps, making it possible to assess the significance of the deviations from the expected statistical characteristics. 2) A new method for predicting the frequencies of occurrence of particular words in a genetic text using the statistical characteristics of "spaced" L-grams. The method can be used for predicting the number of restriction sites in human DNA and in planning experiments on the physical mapping and sequencing of the human genome. 相似文献
108.
Necessity of IgE antibodies and mast cells for manifestation of resistance against larval Haemaphysalis longicornis ticks in mice 总被引:5,自引:0,他引:5
H Matsuda N Watanabe Y Kiso S Hirota H Ushio Y Kannan M Azuma H Koyama Y Kitamura 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(1):259-262
Genetically mast cell-deficient WBB6F1-W/Wv mice showed an apparent defect in manifestation of the resistance against larval Haemaphysalis longicornis ticks, but their serum IgE levels increased more than 100-fold after the second tick infestation. Immune sera obtained from the WBB6F1-W/Wv mice were adoptively transferred to the other WBB6F1-W/Wv mice which had received intracutaneous injections of WBB6F1-+/+ mouse-derived cultured mast cells. Because the resistance against ticks was detectable only when both mast cells and IgE antibodies were available, immediate hypersensitivity reaction appeared to have a physiologic role in the manifestation of the resistance against H. longicornis ticks. 相似文献
109.
In normal rats, before Day 12 of pseudopregnancy, minimal levels of 20 alpha-HSD activity were detected in functional CL whereas those in the residue were 3-5 times higher. When ovulation was blocked for more than 2 weeks by placing rats in a continuously lit environment before the induction of pseudopregnancy, only minimal levels of 20 alpha-HSD activity were detectable in the functional CL and residue before Day 12. In normal pseudopregnant rats, there was a linear increase in 20 alpha-HSD activity from Day 12 to 15 in the functional CL and residue, but the rate of elevation was much higher in functional CL. This tendency was much more clear-cut in rats in the continuous lighting. In immature rats in which pseudopregnancy was induced by PMSG and hCG treatment, 20 alpha-HSD activity peaked twice. The first small peak was attributed to the early regression of some of the large number of corpora lutea, and the changes in 20 alpha-HSD activity in most of the corpora lutea paralleled those in rats in continuous lighting. Bromocriptine abolished the prolactin surges, and in normal pseudopregnant rats an increase in 20 alpha-HSD activity in functional CL started from 12 h and the rate of the increase was accelerated from 36 h afterwards, while a relatively small increase was observed in the residue at 18 h and later.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
110.
Evolutionarily stable stalk to spore ratio in cellular slime molds and the law of equalization in net incomes 总被引:1,自引:0,他引:1
The evolutionarily stable stalk ratio (ESSR) in the cellular slime molds is studied when the fruiting body is formed by multiple clones of various size. The survival probability of a spore cell is assumed to depend on the stalk ratio and the fruiting body size. ESSR is obtained as the non-co-operative equilibrium (Nash solution) that maximizes the fitness of each clone. The following two predictions are obtained: (1) the number of spore cells produced by each clone forming a fruiting body tends to be equalized, even if a variation in clone size exists. As a result, the larger clones do not necessarily enjoy higher fitness than the smaller ones. (2) The stalk ratio and the overall fitness of the fruiting body decrease as the genetic diversity in the fruiting body increases. A condition for the stalk to spore ratio to be invariant of overall fruiting body size is also investigated. Finally, "the law of equalization in net incomes" is proposed, extending result (1) into the broader range of resource allocation problems. 相似文献