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11.
Cerveza PJ Mehrbod F Cotton SJ Lomeli N Linder MC Fonda EG Wickler SJ 《Archives of biochemistry and biophysics》2000,373(2):451-461
Concentrations of ceruloplasmin and copper in milk and blood plasma, the nature of milk ceruloplasmin, and the effects of lactation and gestation on these parameters, as well as the expression of ceruloplasmin mRNA by the mammary gland, were examined in pigs. As seen previously in humans, ceruloplasmin and copper concentrations in sow milk were much higher a few days after birth than 1 month later, averaging 26.5 and 6.6 mg ceruloplasmin/L (by immunoassay) and 1.67 and 0.34 mg total Cu/L, on days 3 and 33 postpartum, respectively. Values for ceruloplasmin oxidase activity (measured with p-phenylene diamine) were 7.8 and 1.3 nmol/min/L, respectively. Daily milk ceruloplasmin production went from 61 to 22 mg/day and daily copper output from 38 to 12 mg/day. In contrast, there was little or no variation in serum ceruloplasmin concentration during lactation or gestation, although total plasma copper was high at the end of gestation. Milk ceruloplasmin was of the same apparent size as serum ceruloplasmin, as determined by SDS-PAGE and immunoblotting, and ceruloplasmin mRNAs of liver and mammary gland were indistinguishable by Northern analysis and RT-PCR of the various exons. Expression of total RNA and ceruloplasmin mRNA, as detected in biopsies of mammary gland, increased markedly upon onset of lactation and then declined during the next month in conjunction with a drop in milk ceruloplasmin production. The results indicate that milk ceruloplasmin, while being the same protein as in plasma, is not derived from the plasma but is produced by the mammary gland. 相似文献
12.
Pasquier CM; Promponas VI; Varvayannis NJ; Hamodrakas SJ 《Bioinformatics (Oxford, England)》1998,14(8):749-750
Summary : FT is a tool written in C++, which implements the Fourier
analysis method to locate periodicities in aminoacid or DNA sequences. It
is provided for free public use on a WWW server with a Java interface.
Availability : The server address is http://o2.db. uoa.gr/FT Contact :
shamodr@atlas.uoa.gr
相似文献
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Recently Sillén-Tullberg & Leimar (1988) modelled a general explanation for the evolution of gregariousness in prey organisms that live exposed, have no means of escape when discovered by a predator, and are small in relation to a potential predator (who thus can sample many prey individuals in one encounter). The model predicts that gregarious prey organisms of that type ought to be distasteful, and that the evolution of gregariousness will be favoured by aposematic coloration facilitating avoidance learning in a predator. Obviously, any protective power of grouping depends on group size. According to the Sillén-Tullberg & Leimar model, (1) “members of small groups may have a higher rate of death from predation than solitary individuals, but above a certain minimum group size, group members do better than solitary individuals; … as group size increases above the minimum value, group members suffer fewer and fewer deaths from predation”. They benefit from the “decreased risk of predator attack on any particular individual”, called dilution effect. (2) “The more prey specimens that the predator needs to sample during avoidance learning, the larger an aggregation needs to be in order for gregariousness to be advantageous”. It is further explained that (3) selection resulting from predation favours increase in group size until it “acts like a predator-satiation mechanism”. 相似文献
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The painted shrimp exhibits a social system of “relative monogamy”. The selective consequences of mate attachment for the individuals have been studied by long term observations and experiments. 相似文献
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Horses have a tendency to utilize a relatively narrow set of speeds near the middle of a much broader range they are capable of using within a particular gait, i.e., a preferred speed. Possible explanations for this behavior include minimizing musculoskeletal stresses and maximizing metabolic economy. If metabolic economy (cost of transport, CT) and preferred speeds are linked, then shifts in CT should produce shifts in preferred speed. To test this hypothesis, preferred speed was measured in trotting horses (n = 7) unloaded on the level and loaded with 19% of their body weight on the level. The preferred speed on the level was 3.33 +/- 0.09 (SE) m/s, and this decreased to 3.13 +/- 0.11 m/s when loaded. In both conditions (no load and load), the rate of O2 consumption (n = 3) was a curvilinear function of speed that produced a minimum CT (i.e., speed at which trotting is most economical). When unloaded, the speed at which CT was minimum was very near the preferred speed. With a load, CT decreased and the minimum was also near the preferred speed of horses while carrying a load. 相似文献
18.
Helmut Albrecht und Wolfgang Wickler 《Journal of Ornithology》1968,109(3):255-263
Zusammenfassung Schmuckbartvögel der GattungTrachyphonus äußern als Begrüßung der Paar-Partner (und wahrscheinlich auch weiterer Familienmitglieder) einen von Art zu Art verschiedenen und verschieden komplizierten, aber wohl nicht paar-spezifischen Duettgesang.Trachyphonus d'arnaudii begleitet ihn mit einem auffälligen Verhalten. Der Gesang wurde analysiert, das Verhalten gefilmt; die strittige Verteilung der Rollen auf die Geschlechter ist erörtert. Während die bisher näher untersuchten duettsingenden Vögel zu den Singvögeln zählen, sind die Bartvögel (Capitonidae) Spechtverwandte.
Mit 4 Abbildungen 相似文献
Summary Barbet birds of the genusTrachyphonus greet their partner (and most likely other members of their family) with a duett song which differs from species to species as well as in complexity, but which is most likely not pair-specific. The song ofTrachyphonus d'arnaudii is accompanied by a conspicuous behaviour pattern. The song was analysed and the behaviour filmed; the controversy on the distribution of the sex roles is discussed. Up to now all more closely investigated duett-singing birds are songbirds; the barbet birds, however, are related to the woodpeckers.
Mit 4 Abbildungen 相似文献
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Social interactions, site attachment and group cohesion were studied in a free-living colony of Epomophorus fruit bats. Daily activities in an undisturbed colony were recorded. Special attention was paid to the peculiar calling behaviour of courting ♂♂ during the night. Structure and repetition rate of their sounds were analyzed in the laboratory. A special mode of acoustic interaction was found and related to the observed spacing out of calling ♂♂ By following feeding animals in the field and by analysis of their faeces we found that besides fruits they eat special leaves which afford steroidal sapogenins. 相似文献