共查询到20条相似文献,搜索用时 31 毫秒
1.
E. Rodriguez M. Aregullin T. Nishida S. Uehara R. Wrangham Z. Abramowski A. Finlayson G. H. N. Towers 《Cellular and molecular life sciences : CMLS》1985,41(3):419-420
Summary Two African species ofAspilia (Asteraceae), which are used medicinally by man and which are eaten by wild chimpanzees in an unusual manner, were found to contain the potent antibiotic thiarubrine A as a major leaf phytochemical. Its presence in leaf material strengthens the view that the feeding behavior of wild chimpanzees is related to special physiological or pharmacological effects on the animals. 相似文献
2.
H. Hemmer 《Cellular and molecular life sciences : CMLS》1976,32(5):663-666
Summary The minimum brain size possible in the relevant wild species and certain colour types which, because of alterations in the neurotransmitter system caused by the respective colour genes, are related to behavioural traits diverging from the wild animal's norm appear to be first-rate bases for domestication either separately or in combination. 相似文献
3.
L. Rasmussen H. Toftlund M. Florin-Christensen J. Florin-Christensen 《Cellular and molecular life sciences : CMLS》1985,41(12):1593-1594
Summary Taking advantage of a synthetic nutrient medium, we have studied which compounds phosphate-starvedTetrahymena thermophila can use as phosphate sources for growth and cell multiplication. Ortho-, trimeta- and -glycero-phosphate are good sources for both the wild type and a food-vacuoleless mutant; phosphorylcholine is used only by the wild type, and 2-aminoethyl phosphonic acid fails to serve as a phosphate source. Since at least two phosphatases are found in the extracellular fluid these results indicate thatTetrahymena can make use of extracellular digestion of nutrients. 相似文献
4.
R E Landsman 《Experientia》1991,47(1):31-38
Little is known about the link between captivity, physiology, and behavior in wild-caught vertebrates. Anecdotal evidence suggests that hormonal changes are responsible for behavioral changes in wild animals brought into captivity. Studying the effects of captivity on reproduction is hampered because wild animals often fail to exhibit sexual behavior under captive conditions. In weakly discharging electric fish, field studies have reported sex differences in electric organ discharges which are rarely seen in the laboratory. I now report the results of a series of laboratory investigations which show that Gnathonemus petersii exhibits seasonal, hormone-dependent, phase-specific sex differences in electric organ discharges. Captivity dramatically alters and may even reverse these sex differences as a result of rapid changes in endogenous plasma hormone levels. These findings have broad implications for research on animal physiology and behavior performed in laboratory settings. 相似文献
5.
R. E. Landsman 《Cellular and molecular life sciences : CMLS》1991,47(1):31-38
Summary Little is known about the link between captivity, physiology, and behavior in wild-caught vertebrates. Anecdotal evidence suggests that hormonal changes are responsible for behavioral changes in wild animals brought into captivity. Studying the effects of captivity on reproduction is hampered because wild animals often fail to exhibit sexual behavior under captive conditions. In weakly discharging electric fish, field studies have reported sex differences in electric organ discharges which are rarely seen in the laboratory. I now report the results of a series of laboratory investigations which show thatGnathonemus petersii exhibits seasonal, hormone-dependent, phasespecific sex differences in electric organ discharges. Captivity dramatically alters and may even reverse these sex differences as a result of rapid changes in endogenous plasma hormone levels. These findings have broad implications for research on animal physiology and behavior performed in laboratory settings. 相似文献
6.
The ascorbic acid content of foliage available to wild primates and bats in Panama (in transition between wet and dry seasons) was lower than that of temperate zone foliage but higher than that of most fruits and vegetables. Intakes of ascorbic acid (mg/kg b.wt/day) by wild primates and frugivorous bats in Panama are much greater than that of most human populations. 相似文献
7.
Summary The ascorbic acid content of foliage available to wild primates and bats in Panama (in transition between wet and dry seasons) was lower than that of temperate zone foliage but higher than that of most fruits and vegetables. Intakes of ascorbic acid (mg/kg b.wt/day) by wild primates and frugivorous bats in Panama are much greater than that of most human populations. 相似文献
8.
Summary Direct observations on the feeding behavior of insect herbivores are uncommon, but important. The important aspects of host-plant selection by phytophagous insects that have been revealed by such observations are the role of chemicals in the leaf surface, and learning. There are few detailed reports of behavior at the leaf surface, but these indicate that many, if not all, insects exhibit behavior pattenrs that can be interpreted as an examination of the quality of the surface and acceptance or rejection may follow without further testing. A number of experiments show that chemicals from the leaf surface commonly contribute to the acceptability or otherwise of a plant and in most cases so far the active chemicals are of widespread occurrence, not having a specific association with the host plant. Some experiments show that the association between surface chemicals and plant palatability is learned, but in other cases there is evidence of an innate response. Habituation to deterrent chemicals has been demonstrated in the laboratory, but not in the field. Food aversion learning also occurs and may be important in dietary switching by polyphagous insects. 相似文献
9.
扫描树结构能够有效地减少集成电路的测试数据量和测试时间,降低电路的测试成本.为减少三维电路中扫描树的叶子节点和硅通孔数量,首先得出了扫描树中叶子节点的最小数量为最大相容组中所含扫描单元数量的结论,然后进一步得到了叶子节点取得最小值的充分必要条件.并在此基础上,提出了一种启发式算法来确定扫描树中相容组的连接顺序,使得叶子节点数量取得最小值的同时能够优化硅通孔的数量.实验结果表明了所提方法的有效性. 相似文献
10.
Administration of the protein synthesis inhibitor, anisomycin, to wild type hamsters produces phase shifts in their circadian rhythms that have similarities to shifts produced by non-photic behavioral stimulation. A mutation that shortens the period of rhythms in hamsters results in altered responsiveness to non-photic input. However, responses of the mutants to anisomycin are unaffected: their phase response curve (PRC) for anisomycin is similar to that of wild types. This suggests that 1) anisomycin is not acting on mechanisms specifically involved in non-photic behavioral phase shifting, and 2) the mutation affects the non-photic input pathway or the pacemaker itself at a point that is upstream from anisomycin's site of action. 相似文献
11.
Administration of the protein synthesis inhibitor, anisomycin, to wild type hamsters produces phase shifts in their circadian rhythms that have similarities to shifts produced by non-photic behavioral stimulation. A mutation that shortens the period of rhythms in hamsters results in altered responsiveness to non-photic input. However, responses of the mutants to anisomycin are unaffected: their phase response curve (PRC) for anisomycin is similar to that of wild types. This suggests that 1) anisomycin is not acting on mechanisms specifically involved in non-photic behavioral phase shifting, and 2) the mutation affects the non-photic input pathway or the pacemaker itself at a point that is upstream from anisomycin's site of action. 相似文献
12.
M Sebald M G Bréfort 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1975,281(4):317-319
Two plasmids which confer resistance to Tetracycline-Chloramphenicol and Erythromycine-Clindamycine were found in a strain of Clostridium perfringens. The plasmid (Tet-Chl) was shown to be transferable to sensitive strains of C. perfringens. The transfer experiments were made with the wild type strain or strains cured by one plasmid or the other as donor strains. 相似文献
13.
A Quevauviller M Hamonniere 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1977,284(1):93-96
Polyalthia oliveri leaf alkaloid, oliveroline, shows in Mice antiparkinsonian properties which decrease or disappear with the alkalo?ds extracted from the bark of the trunk, oliveridine and oliverine. The latter alkaloid has an antihypertensive effect which is not found in oliveridine, only hypotensive by a relaxant close to papaverine action on vascular smooth muscles. 相似文献
14.
H. Hemmer 《Cellular and molecular life sciences : CMLS》1972,28(3):271-272
Summary The absolute and relative braincase capacity was described in the literature as one of the best criteria for distinguishing skulls of European wild cats (Felis silvestris silvestris) and domestic cats (Felis silvestris f. catus). Now it is shown that wild cats of North Africa (Felis silvestris lybica) and South Asia (Felis silvestris ornata), in contrast to the wild cats of Europe and of other parts of Africa, have likewise smaller brain capacities comparable to those of the domestic cat originating in this subspecies group ofFelis silvestris. This gives new evidence for discussing the theory of supposed considerable reduction of the brain size in domestication advocated especially byHerre and his collaborators, the general validity of which is called in question. 相似文献
15.
Summary Isolated leaf mesophyll protoplasts ofAtropa belladonna when cultured in defined liquid culture media regenerate cell walls, divide and form calli. Subsequent induction of shoot and root organogenesis leads to plantlets which grow to maturity after transfer to soil.Acknowledgment. We are indebted to Václav Mandák for skilful technical assistance. 相似文献
16.
Dewaxed leaf surface extracts of 12 plants from Hokkaido, prepared by dipping fresh leaves in chloroform for 3 min, were used in a choice leaf-disk bioassay against larvae of the tobacco cutwormSpodoptera litura. Activity was found only in the extract ofSenecio cannabifolius, a very successful weed in Hokkaido. Individual fractions of the extract, however, were not active. Incorporation of the individual fractions of the surface extracts as well as fractions of the methanolic extracts of the leaf residue into an artificial diet fed to neonateS. litura led to the isolation of ethyl (1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate, the major surface compound, as the active principle. This compound was also present in the methanolic extract of the leaf residue together with methyl (1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate, which had the same growth inhibitory effect on the larvae. The presence of these compounds in the foliar surface and tissue suggests a defensive role against herbivores. 相似文献
17.
利用红叶石楠叶片和茎段作为外植体进行愈伤组织试验,研究了TDZ和AgNO_3及其他植物生长调节刑对红叶石楠愈伤组织诱导的影响效果.结果表明:TDZ和AgNO_3对红叶石楠愈伤组织诱导具有一定的促进作用,但需NAA配合.方能形成愈伤组织.本试验中,培养基1/2MS+AgNO_32.5 m/l+TDZ0.5 mg/l+NAA2.Omg/l对叶片有较好诱导效果,1/2MS+AgNO_32.5 mg/l+TDZ0.5 mg/l+NAA1.0 mg/l对茎段有较好诱导效果.此外,1.5 mg/l的TDZ与0.5 mg/l的2,4-D配比有较好诱导效果.光培养条件下,叶片的诱导率高于茎段;在暗培养下,茎段的诱导率高于叶片. 相似文献
18.
Gertrud Ochs 《Cellular and molecular life sciences : CMLS》1959,15(8):303-303
Summary A virus has been isolated from grape vines diseased with leaf roll which is the cause of this dangerous illness in vineyards. This was proved by means of electromicrographs of the virus particles in pressed juices of all the diseased vine crops examined. The virus is only transmissible by graft and not by juice. 相似文献
19.
Up to 10% of the mouse genome is comprised of endogenous retrovirus (ERV) sequences, and most represent the remains of ancient
germ line infections. Our knowledge of the three distinct classes of ERVs is inversely correlated with their copy number,
and their characterization has benefited from the availability of divergent wild mouse species and subspecies, and from ongoing
analysis of the Mus genome sequence. In contrast to human ERVs, which are nearly all extinct, active mouse ERVs can still be found in all three
ERV classes. The distribution and diversity of ERVs has been shaped by host-virus interactions over the course of evolution,
but ERVs have also been pivotal in shaping the mouse genome by altering host genes through insertional mutagenesis, by adding
novel regulatory and coding sequences, and by their co-option by host cells as retroviral resistance genes. We review mechanisms
by which an adaptive coexistence has evolved. (Part of a Multiauthor Review) 相似文献
20.
L. E. de Magalhães Maria A. Q. Rodrigues Pereira 《Cellular and molecular life sciences : CMLS》1976,32(3):309-310
Summary Measurements of the mating success of wild and ebony strains ofD. melanogaster with different degrees of competition have shown a frequency-dependent effect in both cases, but with a negative correlation for the wild and a positive correlation for the ebony strain.Supported by FAPESP Grant No. 70/049. 相似文献