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31.
Daniel Chappard Christian Alexandre Sabine Palle George Riffat 《Biotechnic & histochemistry》1986,61(2):93-96
Polyester fibers are not dissolved by either glycol methacrylate or methyl methacrylate. Commercial polyester wadding is consequently an advantageous material to use in getting precise orientation of tissue specimens during embedding in methacrylate. 相似文献
32.
Metabolism and Solubilization of Cellulose by Clostridium cellulolyticum H10 总被引:9,自引:2,他引:7 下载免费PDF全文
When Clostridium cellulolyticum was grown with cellulose MN300 as the substrate, the rates of growth and metabolite production were found to be lower than those observed with soluble sugars as the substrate. At low cellulose concentrations, the growth yields were equal to those obtained with cellobiose. The main fermentation products from cellulose and soluble sugars were the same. Up to 15 mM of consumed hexose, a change in the metabolic pathway favoring lactate production similar to that observed with soluble sugars was found to occur concomitantly with a decrease in molar growth yield. With cellulose concentrations above 5 g/liter, accumulation of soluble sugars occurred once growth had ceased. Glucose accounted for 30% of these sugars. A kinetic analysis of cellulose solubilization revealed that cellulolysis by C. cellulolyticum involved three stages whatever cellulose concentration was used. Analysis of these kinetics showed three consecutive enzymatic activity levels having the same Km (0.8 g of cellulose per liter, i.e., 5 mM hexose equivalent) but decreasing values of Vmax. The hypothesis is suggested that each step corresponds to differences in cellulose structure. 相似文献
33.
Summary Home ranges of the Galapagos land iguana (Conolophus pallidus) were examined with respect to food availability and the thermal environment. Activity patterns, the amount of space used per day, and time required to use the entire home range were also investigated. The effects of, and the relationships between, these factors vary seasonally, as do home range sizes and preferred body temperatures.Food supplementation experiments resulted in only temporary reductions in use of space. Home range sizes were not different between the seasons with the least (Fall) and the most (Hot) food availalble, but home ranges were significantly smaller in Garua when food supplies were low, but not as low as in Fall. Calculations of metabolic expenditures in each season suggests that food availability alone does not explain seasonal patterns of home range size in this species.The thermal environment within each home range was characterized by microclimatic measurements and measurements of the area of sun, shade, and semi-shade. An index with units of m2h was used to quantify the thermal quality of each home range. Iguanas exploited optimal (with respect to body temperature) conditions more than would be expected from random use of their home ranges. Thermal transients (due to large body size) and optimal conditions were exploited to the largest degree in Fall.During Garua, low metabolic rates and time constraints imposed by an abundance of stressful thermal environments may result in small home ranges. In Fall, increased temperatures cause higher metabolic rates and allow more time for exploitation of the cooler portions of the home range, hence, home range sizes increase. In the Hot season, there is abundant food and optimal thermal conditions, but home ranges remain large. Searching for preferred foods may cause the large home ranges in this season. 相似文献
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35.
Toshihisa Ohshima Christian Wandrey Miyuki Sugiura Kenji Soda 《Biotechnology letters》1985,7(12):871-876
Summary Screening of leucine and alanine dehydrogenases in thermophilicBacillus strains was carried out to develop their utilization for industrial and analytical catalysts. Out of the 28 thermophilic strains tested, four strains,Bacillus sp. DSM 405, 730 and 1521, andB.
sphaericus DSM 462, abundantly produce both the enzymes. Both the enzyme activities in these thermophiles are enhanced by addition of the substrates to a polypeptone medium. 相似文献
36.
Michel Delarue Thierry Darribere Christian Aimar Jean-Claude Boucaut 《Development genes and evolution》1985,194(5):275-280
Summary Most hybrids betweenBufo bufo andB. calamita obtained by nuclear transplantation become arrested at the early gastrula stage. In both parental controls and the hybrid embryos, the presence and distribution of extracellular matrix was analysed with fluorescent wheat germ agglutinin and by immunolabelling with antibodies directed against fibronectin. InB. bufo andB. calamita gastrulae and in the few hybrids that complete gastrulation, the inner surface of the blastocoel roof is covered by a fibronectin-rich fibrillar matrix. In nucleocytoplasmic hybrids whose development was arrested at the gastrula stage, the fibronectin-containing extracellular matrix was either totally absent or poorly developed and disorganized. 相似文献
37.
Animal community structure as a function of stream size 总被引:1,自引:1,他引:0
Christer Brönmark Jan Herrmann Björn Malmqvist Christian Otto Per Sjöström 《Hydrobiologia》1984,112(1):73-79
The species-area relationship of the island biogeography theory was calculated for macroinvertebrates in 22 coastal, adjacent streams. A z-value of 0.19 was obtained. The low z-value was probably a consequence of the short distances between streams as well as high dispersal rates. In addition, a cluster analysis based on the dissimilarity of species assemblages showed that stream size was of prime importance in categorizing the streams. To a smaller extent water quality affected the community structure in the streams. 相似文献
38.
Summary The behaviour of a drum fermentor and a column fermentor during the sporulation ofPenicillium roqueforti on buckwheat seeds is presented. The main problem encountered during the course of a cultivation is the free water released (about 0.1 ml/g dry matter) which must be removed from the medium. The rotation of the drum fermentor may disturb the growth and the sporulation. The column fermentor thus represents the best way to perform batch cultivation of the fungus: 109 external spores/g dry matter are obtained.Semi-continous cultivation, with sequential emptying and filling, is performed in 1-liter bottles. This kind of cultivation may give a maximal average productivity close to 9.2·106 external spores/g dry matter per hour. A drum fermentor, rotading only when emptying and filling, could represent an alternative to perform this kind of cultivation. 相似文献
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