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691.
Rensch’s rule describes the pattern of sexual size dimorphism (SSD) claiming that in taxa where males are the larger sex,
larger species generally exhibit higher male to female body size ratios. Agreement with Rensch’s rule is manifested by the
slope of the allometric relationship between male and female body size exceeding one. In this paper we have tested the hypothesis
that recent rapid evolutionary changes of body size accompanying domestication process and morphological radiation of domestic
breeds follow Rensch’s rule. We have analyzed literature data on adult body size of males and females in domestic cows, yaks,
buffaloes and other bovines (315, 12, 24 and 2 breeds, respectively) and compared it with SSD in 18 wild species/subspecies
of the subfamily Bovinae. Male to female body mass ratio in domestic cows (1.48) was fairly comparable to that found in other species of domestic and
wild bovines except domestic buffaloes (1.19). In cows we have demonstrated clear positive allometry of male to female body
mass ratio (slope 1.21) predicted by Rensch’s rule, however, no such clear relationship was found when body mass was replaced
by shoulder height. These findings are in agreement with those we have previously reported in other livestock species, goats
and sheep. 相似文献
692.
Marcel De Cuyper Bruno De Meulenaer Pol Van Der Meeren Jan Vanderdeelen 《Biocatalysis and Biotransformation》1995,13(2):77-87
The role played by the surface charge density of the phospholipid coat of nanometer-sized Fe3O4 colloids (so-called “magnetoliposomes”) in the catalytic activity of beef heart cytochrome c oxidase was investigated. Screening of various binary mixtures of the anionic dimyristoylphosphatidylglycerol and the zwitterionic dimyristoylphosphatidylcholine demonstrated that the highest degree of reactivation was found in the lower negative charge range. Pre-incubation of the charged colloidal biocatalytic particles with cytochrome c induced aggregation and reduced overall enzymatic activity. The results are interpreted in terms of a different affinity of the substrate for the various membrane types and of a reorganisation of the enzyme within the membrane matrices. 相似文献
693.
Three isolates of strawberry mottle agent (SMA) from strawberry plants were regularly maintained and multiplied by mechanical
inoculation onChenopodium quinoa plants showing mosaic and mottle symptoms. The use of 5 mM borate buffer pH 8.6 or tap water pH 6.6-7.9 with 4 % (m/v) charcoal
for homogenization resulted usually in 100 % infection. The total of 2090 plants were infected from 2264 inoculated ones under
the same conditions. The infectivity of SMA isolates in crude sap ofC. quinoa was retained from 48 h to 72 h at 20 °C. The dilution end points of SMA isolates were 10-3 while the inactivation temperatures were between 50 and 55 °C. The infectivity of SMA isolates in frozen leaves ofC. quinoa was detected still after six months.
Purification procedure of SMA is based on using low molar 25 mM borate buffer pH 8.3 with cysteine hydrochloride, DIECA and
Tween 20 for homogenization of infectedC. quinoa leaves, polyethyleneglycol precipitation, clarification with octanol, low and high speed centrifugation and sucrose density-gradient
centrifugation. Partially purified preparations are highly infectious, causing mosaic, mottling and tip necrosis ofC. quinoa plants. The agent could not be completely separated from host proteins and it could not be concentrated to a high extent.
Isometric virus-like particles 14-16 nm were observed in partially purified preparations. 相似文献