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The main energy reserves in brown trout, Salmo trutta and Arctic char, Salvelinus alpinus are located in the abdominal cavity and the musculature. The energy content of the rest of the intestines after removal of the gonads, swim bladder, and liver is a good parameter to assess the gross nutritional state of Arctic char and brown trout. This method is laborious, but analysing the dry matter fraction (or the water content) of the same organs instead of their energy content is a practical alternative. The dry matter fraction of these organs expressed as a percentage of its wet weight is here called the 'Gut index'. 相似文献
4.
Present and future needs for algae and algal products 总被引:1,自引:0,他引:1
A review of the present needs, mainly for production of phycocolloids and food condiments, is given. Supply and demand vary from balanced, in some, to disproportionate in other fields. World-wide shortage of agarophytes contrasts with huge, unexploited beds of brown seaweeds.In future, partly conflicting trends will decide the needs for algae and algal products. Growth in the human population, pollution, overexploitation of land and lack of freshwater will encourage use of seaweeds. Modern biotechnology will favour this development, but will also be a serious threat to industrial exploitation of seaweeds. Future uses of marine algae will be decisively influenced by the effort put into and the results coming out of seaweed research. 相似文献
5.
We review the New Caledonian representatives of the Australasian endemic hydroptiline genus Acritoptila, based on examination of a considerable collection of material in the Swedish Museum of Natural History and of types of previously established species. A key for identification of males is given and includes 3 species newly described here: A. parallela
sp. n., A. forficata
sp. n. and A. macrospina
sp. n. For all New Caledonian species, male genitalia are illustrated, and for 5 associated females, distinctive features are illustrated and described. 相似文献
6.
- Several animal species are known to distinguish between their own eggs and eggs of unrelated conspecifics. However, the cues involved in this discrimination are often unknown. These cues were studied using the predatory mite Gynaeseius liturivorus Ehara.
- Adult females of these predatory mites oviposit in clusters and avoid oviposition close to eggs laid by other females, resulting in reduced cannibalism between offspring. Because predatory mites are blind, it was tested whether volatiles of eggs were used as a cue for egg recognition.
- Adult female predatory mites were offered volatile cues of their own eggs and of unrelated conspecific eggs, and females were prevented from contacting the eggs. Predatory mites oviposited closer to their own eggs than to unrelated eggs. This preference was observed even when one own and one unrelated egg were offered as a volatile source.
- These results suggest that adult female predatory mites can determine kinship using volatiles released from the eggs.
7.
Coordinate regulation of phospholipid biosynthesis by serine in Saccharomyces cerevisiae. 总被引:6,自引:4,他引:2
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The addition of L-serine to inositol-containing growth medium repressed membrane-associated CDPdiacylglycerol synthase (CTP:phosphatidate cytidylyltransferase, EC 2.7.7.41) and phosphatidylserine synthase (CDPdiacylglycerol:L-serine O-phosphatidyltransferase, EC 2.7.8.8) activities and subunit levels in wild-type Saccharomyces cerevisiae. Enzyme activities and subunit levels were not repressed when inositol was absent from the growth medium. The addition of L-serine to the growth medium did not affect the phospholipid composition of wild-type cells. CDPdiacylglycerol synthase and phosphatidylserine synthase were not regulated in the S. cerevisiae inositol biosynthesis ino2, ino4, and opi1 regulatory mutants, suggesting that regulation by inositol plus L-serine is coupled to inositol synthesis. Inositol and L-serine did not affect the activities of purified CDPdiacylglycerol synthase and phosphatidylserine synthase. The addition of compounds structurally related to L-serine to the growth medium of wild-type cells also resulted in a repression of CDPdiacylglycerol synthase and phosphatidylserine synthase but only in the presence of inositol. Phosphatidylinositol synthase (CDPdiacylglycerol:myo-inositol 3-phosphatidyltransferase, EC 2.7.8.11) was not regulated by inositol plus L-serine. 相似文献
8.
Effect of growth phase on phospholipid biosynthesis in Saccharomyces cerevisiae. 总被引:11,自引:7,他引:4
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The effect of growth phase on the membrane-associated phospholipid biosynthetic enzymes CDP-diacylglycerol synthase, phosphatidylserine synthase, phosphatidylinositol synthase, and the phospholipid N-methyltransferases in wild-type Saccharomyces cerevisiae was examined. Maximum activities were found in the exponential phase of cells grown in complete synthetic medium. As cells entered the stationary phase of growth, the activities of the CDP-diacylglycerol synthase, phosphatidylserine synthase, and the phospholipid N-methyltransferases decreased 2.5- to 5-fold. The subunit levels of phosphatidylserine synthase and the cytoplasmic-associated enzyme inositol-1-phosphate synthase were not significantly affected by the growth phase. When grown in medium supplemented with inositol-choline, cells in the exponential phase of growth had reduced CDP-diacylglycerol synthase, phosphatidylserine synthase, and phospholipid N-methyltransferase activities, with repressed subunit levels of phosphatidylserine synthase and inositol-1-phosphate synthase compared with cells grown without inositol-choline. Enzyme activity levels remained reduced in the stationary phase of growth of cells supplemented with inositol-choline. The phosphatidylserine synthase and inositol-1-phosphate synthase subunit levels, however, were depressed. Phosphatidylinositol synthase (activity and subunit) was not affected by growth in medium supplemented with or without inositol-choline or the growth phase of the culture. The phospholipid composition of cells in the exponential and stationary phase of growth was also examined. The phosphatidylinositol to phosphatidylserine ratio doubled in stationary-phase cells. The phosphatidylcholine to phosphatidylethanolamine ratio was not significantly affected by the growth phase of cells. 相似文献
9.
Jens Kvist Nielsen Arne Henrik Kirkeby-Thomsen Marianne K. Petersen 《Entomologia Experimentalis et Applicata》1989,53(2):157-166
Host plant relations of the monophagous weevil Ceutorhynchus constrictus Marsh. (Coleoptera: Curculionidae: Ceutorhynchinae) feeding on garlic mustard, Alliaria petiolata (Bieb.) Cavara & Grande (Cruciferae) were studied in the laboratory. Most other crucifers were rejected in choice tests using garlic mustard as a reference plant, but Brassica nigra, Sinapis alba and Thlaspi arvense were as acceptable as the host plant. Flowering plants of Descurainia sophia were acceptable while young plants of this species were not. The most important feeding stimulants in extracts of garlic mustard were uncharged, water soluble compounds. The most abundant glucosinolate in garlic mustard, sinigrin, was a feeding stimulant, too. However, the feeding stimulatory activity of sinigrin was only expressed in the presence of still unidentified uncharged compounds from garlic mustard leaves. Host plant relations in monophagous crucifer-feeding insects is discussed in relation to the distinctness of glucosinolate patterns found in their host plants.
Zusammenfassung Ceutorhynchus constrictus Marsh. (Coleoptera: Chrysomelidae: Ceutorhynchinae) ist ein monophager Rüsselkäfer, der an Knoblauchhederich frisst. Das Wirtswahl-Verhalten dieses Käfers ist im Labor untersucht worden. Die meisten Crucifiren waren im Wahlversuche nicht akzeptiert, wenn Knoblauchhederich als Vergleichspflanze vorhanden war. Von Brassica nigra, Sinapis alba, und Thlaspi arvense wurden im Vergleich gleiche Mengen verzehrt wie von der Wirtspflanze. Blühende Descurainia sophia Pflanzen wurden, im Gegensatz zu Jungpflanzen der gleichen Art, angenommen. Die wichtichsten Phagostimulanten in Extrakten von Knoblauchhederich-Blättern waren ungeladene, wasserlösliche Substanzen. Das häufigste Glukosinolat im Knoblauchhederich, Sinigrin, war auch ein Phagostimulant. Doch war die phagostimulierende Wirkung von Sinigrin nur in Kombinationen mit noch nicht identifizierten, ungeladenen Substanzen aus Knoblauchhederich-Blätter nachweisbar. Wirtspfanzen-Beziehungen von monophagen Insekten werden diskutiert im Zusammenhang mit der Eigenart des Glukosinolat-Inhaltes ihrer Wirtspflanzen.相似文献
10.
Energy metabolism in glutamatergic neurons,GABAergic neurons and astrocytes in primary cultures 总被引:9,自引:0,他引:9
Several aspects of energy metabolism (glucose utilization, lactate production,14CO2 production from labeled glucose, glutamate or pyruvate, oxygen consumption and contents of ATP and phosphocreatine) were measured in cerebellar granule cells (glutamatergic) in primary cultures and compared with corresponding data for cerebral cortical neurons (mainly GABA-ergic) and astrocytes. Cerebellar granule cells and astrocytes were metabolically more active than cerebral cortical neurons. Glutamate which is utilized as a major metabolic fuel as astrocytes and, to a lesser extent, in cerebral cortical neurons, was virtually not oxidized in cerebellar granule cells.Special Issue dedicated to Prof. Holger Hydén. 相似文献