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11.
The fruit bodies of the Basidiomycete Scleroderma polyrhizum have been shown to contain the steroids ergosta-4,6,8(14) 22-tetraen-3-one and 5α,8α-epidoxyergosta-6,22-dien-3β-ol and also palmitic and oleic acids.  相似文献   
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The mortars covering some walls of the Roman city of Baelo Claudia (Cadiz, Spain) support an abundant colonization of cyanobacteria, algae and lichens. The distribution of these organisms is closely related to microclimatic parameters. Furthermore, the development, specific composition and biomass of algal cryptoendolithic communities are related to the wall orientation. The effect of these communities on mortar deterioration is discussed.  相似文献   
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Abstract In young spermatids of Culex tigripes, microtubules organize a manchette which surrounds the nucleus. When the nucleus elongates, 1–5 expansions appear on the wall of the microtubules. They grow and branch out while the nucleus elongates and chromatin condenses. Expansions are straight or curved in shape. They have the same thickness as the microtubule walls, but they rarely constitute links between microtubules. The manchette disappears naturally at the end of spermiogenesis. The action of colchicine on spermatids leads to the complete disappearance of the microtubules and expansions, and inhibits the lengthening of the nucleus.  相似文献   
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Very short-term feeding activity of the cladoceran Ceriodaphniasp. was investigated in situ in a eutrophic reservoir in thesouth of Spain, using fluorimetric analysis of the gut pigmentcontent in periods when the water column was relatively mixedor strongly stratified. The results obtained in the mixed watercolumn showed a clear increase in gut pigment content at dawn,a period sampled with high frequency. The accumulation of thecladoceran at the depth of maximum concentration of phytoplankton,and the high gut pigment concentration in cladocerans at thatdepth just after dawn, suggested active feeding of Ceriodaphniaon phytoplankton at that time. During stratification, the abundanceof Ceriodaphnia was higher, but the gut pigment contents werevery low and they did not reflect any clear feeding patterns,with either time or depth. Changes in phytoplankton concentrationand composition between the relatively mixed and the stratifiedwater column suggest a shift in feeding activity from herbivorousto.  相似文献   
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Summary The kinetic parameters of the yeastDebaryomyces hansenii grown in continous cultivation on D-xylose were determined by different methods. While the values obtained for μm by the steady state and the washout methods only gave a 3% difference, the determined Ks values by the steady state and the maximal biomass output methods led a to a 305% difference. The latter method was suggested to overestimate the Ks value.  相似文献   
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This paper describes a computational algorithm (STADEERS-STAtisticalDesign of Exeriments in Enzyme ReactorS) for the statisticaldesign of biochemical engineering experiments. The type of experimentthat qualifies for this package involves a batch reaction catalyzedby a soluble enzyme where the activity of the enzyme decayswith time. Assuming that both the catalytic action and the deactivationof the enzyme obey known rate expressions, the present codeis helpful in the process of obtaining estimates of the kineticparameters by providing as output the times at which samplesshould be withdrawn from the reacting mixture. Starting D-optimaldesign is used as a basis for the statistical approach. ThisBASIC code is a powerful tool when fitting a rate expressionto data because it increases the effectiveness of experimentationby helping the biochemical kineticist obtain data points withthe largest possible informa tional content.  相似文献   
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In this paper we report a bloom of Gyrodinium cf. aureolum occurringin an estuary of the north-west coast of Spain. It was sampledin late August 1989, in shallow waters 2 m deep in the Ria ofPontevedra. Its temperature was 19.5°C and salinity 35  相似文献   
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