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991.
J. R. Evans 《Planta》1986,167(3):351-358
Photosynthesis in two cultivars of Triticum aestivum was compared with photosynthesis in two lines having the same nuclear genomes but with cytoplasms derived from T. boeoticum. The in-vitro specific activity of ribulose-1,5-bisphosphate carboxylase (RuBPCase; EC 4.1.1.39) isolated from lines with T. boeoticum cytoplasm was only 71% of that of normal T. aestivum. By contrast, the RuBPCase activities calculated from the CO2-assimilation rate at low partial pressures of CO2, p(CO2), were the same for all lines for a given RuBPCase content. This indicates that both types of RuBPCase have the same turnover numbers in-vivo of 27.5 mol CO2·(mol enzyme)–1·s–1 (23°). The rate of CO2 assimilation measured at normal p(CO2), p
a
=340 bar, and high irradiance could be quantitatively predicted from the amount of RuBPCase protein. The maximum rate of RuBP regeneration could also predict the rate of CO2 assimilation at normal ambient conditions. Therefore, the maximum capacities for RuBP carboxylation and RuBP regeneration appear to be well-balanced for normal ambient conditions. As photosynthetic capacity declined with increasing leaf age, the capacities for RuBP carboxylation and RuBP regeneration declined in parallel.Abbreviations PAR
photosynthetically active radiation
- RuBP(Case)
ribulose-1,5-bisphosphate (carboxylase) 相似文献
992.
Kenji Hayasaka Yoshi Kawamoto Takayoshi Shotake Ken Nozawa 《Primates; journal of primatology》1986,27(1):103-114
We calculated the probability of paternity exclusion (P) in 6 troops of rhesus and Japanese macaques housed in open enclosures and 68 wild troops of Japanese, crab-eating, and toque
macaques using 33 genetic loci which encoded the blood protein variations detected by electrophoretic techniques. In the open
enclosures, especially of rhesus troops, we obtained a fairly high probability of paternity exclusion and succeeded in determining
the fathers of offspring. However, we found significant differences between the observed and calculated probabilities in most
of the troops. These differences were ascribed to a situation whereby the Hardy-Weinberg equilibrium had not been attained
in the troops and/or the numbers of variable loci were too small. In the wild troops of Japanese, crab-eating, and toque macaques,
the means ofP were 0.2274 (0.0192–0.5017), 0.4635 (0.1676–0.7151), and 0.7382 (0.6266–0.7954), respectively. We also estimated the number
of loci needed to determine the fathers of offspring with a probability of 0.8 assuming that ten males were present in the
troop. The estimated number was about 13.5 times, 5 times and 1.8 times the number of loci examined on average in the troops
of Japanese, crab-eating and toque macaques, respectively. This means that determination of most of the fathers of offspring
in wild troops of these macaques, even of toque macaques which have a rather high probability of paternity exclusion, is difficult
so long as we employ only electrophoretic techniques. 相似文献
993.
D. R. Marshall J. J. Burdon W. J. Müller 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,71(6):801-809
Summary Existing theoretical models have led to conflicting predictions concerning the likely effect of the widespread use of dirty crop multilines on the evolution of virulence in pathogen populations. Here we attempt to clarify these problems by extending existing models to include selection against unnecessary genes for virulence at two different stages in the life cycle of the pathogen. The results of these studies indicate that the stage of the life cycle at which selection occurs can significantly influence the evolution of virulence in pathogen populations growing on multiline varieties. 相似文献
994.
E. J. Eisen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,73(1):148-157
Summary Correlated responses to selection for increased 3–6 week postweaning gain in male mice were estimated for seven internal organs (testes, spleen, liver, kidneys, heart, small intestine (S intest) and stomach) weighed at specific degrees of maturity in body weight (37.5, 50.0, 62.5, 75.0, 87.5 and 100%). Correlated responses in organ weights were generally large, but the magnitude and direction of response depended upon whether 1) comparisons were made at the same age, degree of maturity or body weight and 2) absolute or proportional organ weights were used. The selected line (M16) weighed more and had larger organ weights than controls (ICR) when compared at either the same degree of maturity or the same age, indicating positive genetic correlations between body weight and the respective organ weights. Positive correlated responses were found in spleen weight/body weight at all degrees of maturity and in liver and S intest weights as a proportion of body weight at some degrees of maturity. Testes, kidneys, heart and stomach weights as a proportion of body weight had negative correlated responses, though this was consistent only for kidneys across all degrees of maturity. Correlated responses in organ weights adjusted for body weight by covariance analysis were positive for spleen, S intest and stomach and negative for testes and kidneys. Based on the constrained quadratic model, degree of maturity in organ weight relative to degree of maturity in body weight responded positively for testes, kidneys and S intest and negatively for spleen and liver. Selection for increased growth caused negative correlated responses in allometric growth of testes, kidneys, S intest and stomach.Paper No. 10,545 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, 27695-7601. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Research Service of the products named, nor criticism of similar ones not mentioned 相似文献
995.
M. Hühn 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,73(1):53-60
Summary Theoretical studies on the necessary numbers of components in mixtures (for example multiclonal varieties or mixtures of lines) have been performed according to the relations between the juvenile-mature correlations of mixtures and their number of components. For the juvenile-mature correlation rE based upon the values of the single components (= component means at juvenile and mature ages) and the juvenile-mature correlation rM based upon the means of mixtures of different components we usually will have rM>rE. Furthermore, rM will increase with an increasing number of components in the mixtures. The effectiveness of an early selection will be mainly determined by the magnitude of the juvenile-mature correlation. If we have rM>rE an improvement of early testing can be realized by using mixtures instead of single components. But, what are the necessary numbers of components so that rM will be sufficiently high to enable an effective early selection of mixtures? Some relations between rE and rM can be obtained and conclusions have been derived.The statistical approach significant difference between rE and rM for a given numerical value of rM leads to estimates for the necessary number n of components dependent on rM, , rE and N where: N = total number of components, which are available for the composition of mixtures and = error probability. For different tree species rE can be estimated by an appropriate formula which depends on T with T = time (in years) from planting date until the mature age.Lambeth's formula, for example, has been developed for height growth in pines. For this situation numerical calculations are performed using rM=0.90 and =0.05. The necessary numbers n for T=5, T=10, T=20 and T=50 are: 6, 9, 10 and 12 (for N=50); 13, 17, 20 and 23 (for N=100); 26, 34, 40 and 46 (for N=200); 38, 51, 60 and 69 (for N=300); 64, 85, 100 and 114 (for N=500) and 128, 171, 199 and 228 (for N=1,000). The dependence of these necessary numbers n of components on different type I errors and different levels of rM have been investigated numerically. 相似文献
996.
Abstract Changes in cell volume and solute content upon hyperosmotic shock have been studied for six unicellular blue-green algae (cyanobacteria): Synechococcus PCC 6301, PCC 6311; Synechocystis PCC 6702, PCC 6714, PCC 6803 and PCC 7008. The extent of change in volume was shown to be dependent upon the solute used to establish the osmotic gradient, with cells in NaCl showing a reduced shrinkage when compared to cells in media containing added sorbitol and sucrose. Uptake of extracellular solutes during hyperosmotic shock was observed in Synechocystis PCC 6714, with maximum accumulation of external solutes in NaCl and minimum solute uptake in sucrose solutions. Conversely, solute loss from the cells (K+ and amino acids) was greatest in sucrose-containing media and least in NaCl. The results show that these blue-green algae do not behave as ‘ideal osmometers’ in media of high osmotic strength. It is proposed that short-term changes in plasmalemma permeability in these organisms may be due to transient membrane instability resulting from osmotic imbalance between the cell and its surrounding fluid at the onset of hyperosmotic shock. 相似文献
997.
Soichi Kojima Wakako Soga Hiromi Hagiwara Motoyuki Shimonaka Yuji Saito Yuji Inada 《Bioscience reports》1986,6(12):1029-1033
We have succeeded in corroborating the enhancing effect of vitamin A, vitamin C, sitosterol and fucosterol on the fibrinolytic activity of endothelial cells. The assay system consisted of anin situ dissolution of a fibrin layer coated onto a culture dish, over which endothelial cells were grown in a culture medium containing 10 % serum. The dissolution was enhanced by the addition of these vitamins and phytosterols to the culture medium.To whom correspondence should be addressed. 相似文献
998.
L. S. Jensen G. L. Colnago K. Takahashi Y. Akiba 《Biological trace element research》1986,10(1):11-18
Experiments were conducted to study the effect of marginal levels of selenium and vitamin E on plasma thyroid hormones of
meattype chicks. Plasma thyroxine (T4) was significantly increased when a semipurified diet was supplemented with either selenium or vitamin E. Triiodothyronine
(T3) was also significantly increased by vitamin E and in one experiment with selenium supplementation. No significant increase
in these hormones was observed in birds fed a corn-soybean-meal diet supplemented with these nutrients. Plasma corticosterone
level was reduced and weight of the bursa of Fabricius increased by selenium or vitamin E supplementation. These nutrients
may be necessary for providing the optimum thyroid conditions for activity of thyroid peroxidase. 相似文献
999.
Analyses for phytate by an indirect precipitation method and for the minerals calcium (Ca), zinc (Zn), iron (Fe), copper (Cu),
and manganese (Mn) by atomic absorption spectrophotometry were carried out on 100 foods available in New Zealand. Foods with
1% phytate (dry weight basis) included untoasted muesli, rolled oats, wheat germ, wheat bran, soybean, and some soy products.
Most breads contained between 0.35 and 0.60% phytate; legumes on average had 0.62% phytate, as did snack bars. There was a
wide variation in Ca and Zn contents: There was a tenfold variation in Ca content among the legume products, whereas there
was a seventyfold variation in Zn content among the cereals. The phytate: Zn molar ratio, which is presumed to indicate the
biovailability of Zn, was above 20∶1 for two-thirds of the cereals and almost all of the snack bars; it was above 15∶1 for
one-third of the breads, almost all of the legumes, and half of the legume products. These high phytate: Zn molar ratios,
as well as some Ca: phytate molar ratios above 6∶1, indicate that there might be a reduced biovailability of Zn in many of
the foods analyzed in this study. 相似文献
1000.
Dipple Anthony Pigott Margaret A. Milner John A. 《Biological trace element research》1986,10(2):153-157
Since selenium has been found to exert a protective action against carcinogenesis in various systems, the mechanism where-by
sodium selenite inhibits DNA binding of the carcinogen, 7,12-dimethylbenz[a]anthracene, was investigated. It was found that
selenite preferentially reduced DNA binding occurring through ananti-dihydrodiol epoxide metabolite of this carcinogen by inhibiting the induction of an enzyme system that generates this specific
reactive metabolite. 相似文献