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881.
N. Itoigawa T. Tanaka N. Ukai H. Fujii T. Kurokawa T. Koyama A. Ando Y. Watanabe S. Imakawa 《Primates; journal of primatology》1992,33(1):49-68
Demographic and reproductive data were analyzed for a period of 28 years in the females of a free-ranging group of Japanese
macaques at Katsuyama, Okayama Prefecture, Japan. The overall mean, age-specific fecundity rates were 5.43% for 4-year-olds
and 41.86% for 5-year-olds, increasing to a peak of 66.67% for 13-year-olds. Fecundity remained relatively high (52.31–54.24%)
in 16–19-year-olds, but decreased sharply (45.45–17.86%) in 20–23-year-olds, and became very low in 24–26-year-olds. Females
aged 27 years or more did not produce infants. The average age at first birth was 5.41 years. Births peaked in mid-May. The
timing of the first births each year remained essentially unchanged during the study period, whereas the timing of the median
and last births shifted towards the later part of the season. The mean interbirth interval for all females was 1.56 years.
The value was 1.54 years for multiparous females and 1.29 years for females following infant loss. These intervals were significantly
shorter than those for primiparous females, and females with surviving infants. The overall mean infant mortality within the
first year of life was 10.2%. The value was 8.6% for 10–14-year-olds, and 7.5% for 15–19-year-olds. The timing of birth differed
among the four female matrilineal dominance rank-classes. The female fecundity rates increased as a function of matrilineal
dominance rank. It is suggested that all demographic and reproductive data should be analyzed in detail with respect to the
group's history. 相似文献
882.
Molecular mechanics calculations of dA12·dT12 and of the curved molecule d(GCTCGAAAAA)4·d(TTTTTCGAGC)4 总被引:9,自引:0,他引:9
Using the AMBER software package (Weiner and Kollman 1981) substantially modified for electrostatic contributions, the structural energies of the double-stranded oligonucleotides dA12·dT12 and d(GCTCGAAAAA)4·d(TTTTTCGAGC)4 were minimized. Using various starting structures for the molecule dA12·dT12, one final structure is obtained which possesses the experimentally determined properties of poly(dA)·poly(dT). This structure is an A-form-B-form-hybrid structure similar to that of Arnott et al. (1983). The dA-strand is similar to an A-form while the dT-strand is similar to normal B-form. This structure and separately optimized B-form sequence stretches were used to construct the double-stranded fragment d(GCTCGAAAAA)4 which again was optimized. This sequence, when imbedded in a DNA fragment as contiguous repeats, shows a gel migration anomaly which has been interpreted as stable curvature of the DNA (Diekmann 1986). The calculated structure of this sequence indeed has a curved helix axis and is discussed as a model for curved DNA. A theoretical formalism is presented which allows one to calculate the structural parameters of any nucleic acid double helix in two different geometrical representations. This formalism is used to determine the parameters of the base-pair orientations of the curved structure in terms of wedge as well as cylindrical parameters. In the structural model presented here, the curvature of the helix axis results from an alternation of two different DNA structures in which the base-pairs possess different angles with the helix axis (cylinder tilt). Resulting from geometric restraints, a negative cylinder tilt angle correlates strongly with the closing of the minor groove (wedge roll). The blocks with different structure are not exactly coincident with the dA5-blocks and the B-DNA stretches. Within the dA5 block, base-pair tilt and wedge roll adopt large values which proceed into the 3 flanking B-DNA sequence by about one base-pair. These properties of the structure calculated here are discussed in terms of different models explaining DNA curvature. 相似文献
883.
Geographic variation in protein content of wild barley,Hordeum spontaneum, and the associations of protein content with ecological and allozyme markers were tested in an attempt to derive predictive guidelines for conservation and utilization in breeding programs. The study involved 195 genotypes of wild barley from 25 populations, 15 central and 10 marginal. These populations had been tested earlier for allozymic variation (Nevo & al. 1979 a, b). The results indicate that protein content varies both within, but particularly between populations. Notably, the 10 marginal populations exhibit high protein content but low kernel weight, as compared with the 15 central populations which displayed lower protein content but high kernel weight. Three variable combinations of climatic factors explain 40% of the variability in protein content among populations. Likewise, 3 variable combinations of allozyme allele frequencies explain a significant degree of spatial variance in protein content (R square = 0.63). — We conclude that natural populations of wild barley in Israel contain large amounts of yet untapped genes for protein content. These could be effectively screened and utilized for producing high protein cultivars of barley by following ecological and allozymic markers as predictive guidelines in screening natural populations of wild barley. 相似文献
884.
Sixty-five soybean varieties were tested in the field for resistance to Rotylenchulus reniformis. Criteria for resistance or susceptibility were root necrosis, nematode recovery from roots and soil, and egg production. Nine varieties were resistant, 13 moderately resistant, 26 moderately susceptible, and 17 susceptible. Linear correlations between resistance rating and each assessment parameter were highly significantly positive, suggesting that any of the parameters could be used to identify resistance. There were also highly significant positive linear correlations between any two combinations of parameters, indicating that they were reciprocally related. 相似文献
885.
Effect of the preventive-therapeutic administration of melatonin on mammary tumour-bearing animals 总被引:2,自引:0,他引:2
Saez MC Barriga C Garcia JJ Rodríguez AB Ortega E 《Molecular and cellular biochemistry》2005,268(1-2):25-31
Melatonin has been reported to be involved in the feedback between neuroendocrine and immune functions and to exert oncostatic actions. Likewise, this hormone seems to lengthen life span in healthy animals. As of present, most studies have analysed the therapeutic effect of melatonin on cancer growth, but few have tested the preventive effect of melatonin in reducing the risk of cancer. Thus, the aim of this study was to evaluate the preventive-therapeutic effects of melatonin on rats with DMBA-induced mammary tumours, and to examine the effect of melatonin on the first line of cell defence against cancer (macrophages and NK cells) and on some of the neuroendocrine factors that are involved in the development of tumours (prolactin and catecholamines). Melatonin treatment (5 mg/day/animal) began one month prior to DMBA (9,10-dimethyl-1,2-benzanthracene) administration to females Sprague Dawley rats. It was found that the treatment led to an increase in survival and in latency time in the tumour-bearing rats. Although the melatonin treatment did not influence either the phagocytic capacity of macrophages or the number of peripheral blood NK cells, it did stabilise the levels of prolactin by returning the concentrations of this hormone to those of the healthy animals. We conclude that melatonin can exert an oncostatic action, lengthening the survival time of mammary tumour-bearing animals, and suggest that this effect is due, at least in part, to regulating the neuroendocrine parameters of tumour-bearing animals, bringing them closer to their optimal physiological status. (Mol Cell Biochem 268: 25–31, 2005) 相似文献
886.
Sex steroid inhibitors were used to characterize the effects of 17beta-estradiol (E2) and testosterone (T) on the sexual growth dimorphism of Eurasian perch juveniles. In experiment 1, growth responses to different doses of either E2 (25, 50, 75, and 100 mgkg(diet)-1) or fadrozole (Fa; 50 and 100 mgkg(diet)-1) were compared in triplicate tanks of 30 fish each during 85 days. In experiment 2, five diets containing (50 mgkg(diet)-1) Tamoxifen (Ta), Flutamide (Flu), Fa, E2, and T were tested in triplicate tanks of 20 fish each during 90 days. Steroid supplementation or inhibition increased or decreased E2 and T plasma levels. Moreover, E2 treatment induced a higher plasma vitellogenin level but decreased triidothyronine levels. Brain aromatase activity (AA) was lower in Fa-treated fish than in other groups. In experiment 1, E2 supplementation did not promote growth, but high doses had negative effects as did Fa. In experiment 2, a greater growth response was observed only in E2-treated females in relation to higher food intake (FI) not feeding efficiency. Fa also promoted growth and FI both in females and males during the last month of the experiment. Other treatments did not affect growth, but T treatment decreased FI in males. In conclusion, the results did not provide clear evidence for E2 action on sexual growth dimorphism, but showed that testosterone may decrease growth in males by decreasing food intake in Eurasian perch. Therefore, the acceleration of male-to-female growth differences with age may not be a result of promotion of growth in females by estrogens, but a consequence of a reduction in growth by increased secretion of androgens in males. 相似文献
887.
888.
Cadmium Toxicity: The effect on Macro- and Micro-Nutrient Contents in Soybean Seedlings 总被引:3,自引:0,他引:3
The effect of Cd (10, 100, and 200 M) on tissue contents of macronutrients (N, P, K, Ca, Mg) and micronutrients (Fe, Zn, Cu, Mn) was investigated in hydroponically grown soybean (Glycine max) seedlings. Concentration changes of analysed elements observed against increasing Cd accumulation indicated that acute Cd-phytotoxic effect monitored through chlorophyll content was not a consequence of nutrient deficiency. 相似文献
889.
Saadat M 《Biochemical and biophysical research communications》2004,324(2):584-587
In order to find the effect of genetic polymorphisms of glutathione S-transferase M1 (GSTM1) and GSTT1 on hematological changes of individuals chronically exposed to natural sour gas, the present study was done. Study subjects (59 males, 55 females) were residents of contaminated areas of Masjid-i-Sulaiman (southwest of Iran). The GSTM1 and GSTT1 genotypes were determined using a polymerase chain reaction-based method. The multiple linear regression method was applied. There is significant association between GSTs genotypes and either hemoglobin (t=2.185, P=0.031) or hematocrit (t=2.454, P=0.016). Also there is weak association between GSTs genotypes and WBC counts (t=1.802, P=0.074). The hemoglobin and hematocrit levels and WBC counts increased in individuals who had null genotypes of GSTM1 and GSTT1 compared to subjects with one or two active genes. Also the levels of hemoglobin and hematocrit and WBC counts increased in persons with one active genotype compared to subjects who had two active genes. There is no significant association between neither platelet nor WBC differential parameters and GSTs genotypes. 相似文献
890.
Fifteen years' record of airborne allergenic pollen and meteorological parameters in Thessaloniki,Greece 总被引:1,自引:0,他引:1
Gioulekas D Balafoutis C Damialis A Papakosta D Gioulekas G Patakas D 《International journal of biometeorology》2004,48(3):128-136
A pollen calendar has been constructed for the area of Thessaloniki and relationships between pollen transport and meteorological parameters have been assessed. Daily airborne pollen records were collected over a 15-year period (1987-2001), using a Burkard continuous volumetric pollen trap, located in the centre of the city. Sixteen allergenic pollen types were identified. Simultaneously, daily records of five main meteorological parameters (mean air temperature, relative humidity, rainfall, sunshine, wind speed) were made, and then correlated with fluctuations of the airborne pollen concentrations. For the first time in Greece, a pollen calendar has been constructed for 16 pollen types, from which it appears that 24.9% of the total pollen recorded belong to Cupressaceae, 20.8% to Quercus spp., 13.6% to Urticaceae, 9.1% to Oleaceae, 8.9% to Pinaceae, 6.3% to Poaceae, 5.4% to Platanaceae, 3.0% to Corylus spp., 2.5% to Chenopodiaceae and 1.4% to Populus spp. The percentages of Betula spp., Asteraceae (Artemisia spp. and Ambrosia spp.), Salix spp., Ulmaceae and Alnus spp. were each lower than 1%. A positive correlation between pollen transport and both mean temperature and sunshine was observed, whereas usually no correlation was found between pollen and relative humidity or rainfall. Finally, wind speed was generally found to have a significant positive correlation with the concentrations of 8 pollen types. For the first time in the area of Thessaloniki, and more generally in Greece, 15-year allergenic pollen records have been collected and meteorological parameters have been recorded. The airborne pollen concentration is strongly influenced by mean air temperature and sunshine duration. The highest concentrations of pollen grains are observed during spring (May). 相似文献