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1.
This paper comments on: Low, B. S., Alexander, R. D., and Noonan, K.M. Human hips, breast, and buttocks: Is fat deceptive? Ethology and Sociobiology 8: 249-247, 1987. In it I argue that:
  • 1.1. Sexual selection has probably not been the most important selection pressure on
  • 2.female human body shape.
  • 3.2. Male humans in different cultures find different aspects of the female body attractive
  • 4.and therefore are unlikely to have exerted consistent directional sexual selection on
  • 5.the female body.
  • 6.3. Breast size is not correlated with lactation success.
  • 7.4. Visible hip width is not correlated with parturition success.
  • 8.5. Women would lower their fitness if they tried to deceive men about their internal
  • 9.pelvic dimensions.
  • 10.6. There are many alternative hypothesis to explain the existence of fat onwomen's
  • 11.breast, hips, and buttocks.
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2.
  • 1.1. Several pathways of carbohydrate metabolism were evaluated in three different tissues—liver, gonad and kidney—of a hatchery-reared population of rainbow trout (Oncorhynchus mykiss) which characterised two different stages of their gonadal maturation, i.e. previtellogenesis and established exogenous vitellogenesis.
  • 2.2. A fall in liver glycogen levels was observed during exogenous vitellogenesis. A decrease in activity of the enzymes involved in glycolysis and in the pentose phosphate shunt was also observed, suggesting that at the end of exogenous vitellogenesis the necessity of energy and reducing power has decreased compared to the situation at the onset of this period.
  • 3.3. The main changes observed in gonad during vitellogenesis were the decreased activity of glycolysis and the pentose phosphate shunt as well as increased glycogen levels. The stored glycogen should be used later in association with the embryo development.
  • 4.4. No major changes were observed in kidney metabolism throughout the vitellogenic process.
  • 5.5. Exogenous vitellogenesis in rainbow trout is mainly associated with increased glycogen levels in the gonad and decreased metabolic activity in the liver.
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3.
  • 1.1. Bactrocera latifrons fruit flies recovered from four solanaceous fruits (Capsicum annuum, Lycopersicon esculentum, Solanum pseudocapsicum and Solanum melongena) in Peninsular Malaysia were analyzed for a total of 15 gene-enzyme systems comprising 21 loci.
  • 2.2. Eleven loci—aAdh, Aldox, Ald, Est-F, Est-S, Hk-F, Ldh, cMdh, Me, Pep-A and Pep-C—were invariant.
  • 3.3. Of the polymorphic loci, cathodal alcohol dehydrogenase, glucose phosphate isomerase, glycerol-3-phosphate dehydrogenase, hydroxybutyrate dehydrogenase, isocitrate dehydrogenase, anodal malate dehydrogenase and phosphoglucomutase were represented by two alleles each, while hexokinase-S, peptidase-B and phosphogluconate dehydrogenase were represented by three alleles each.
  • 4.4. The proportion of polymorphic loci ranged from 0.28 to 0.33, while the mean heterozygosity ranged from 0.04 to 0.13.
  • 5.5. The genetic variability is associated with the host range.
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4.
  • 1.1. The mechanism of action of disulfiram on the respiratory electron transport system of the liver mitochondria was studied in vitro.
  • 2.2. Disulfiram inhibited the respiration supported by malate-glutamate as well as succinate.
  • 3.3. Mitochondrial respiration inhibition was dependent upon alteration of —SH groups.
  • 4.4. The inhibitory action of disulfiram might be related to the crosslinking of several proteins of the inner mitochondrial membrane.
  • 5.5. The effects described above could be attributed to disulfiram per se and not to the main metabolite diethyldithiocarbamate.
  相似文献   

5.
6.
  • 1.1. A starvation test was conducted in small beakers with stage 1 (S1) and stage 2 (S2) Macrobrachium rosenbergii larvae to determine optimal salinities.
  • 2.2. Experiments were first performed with S2 larvae at 13 ppt to identify a suitable medium made with artificial sea salts.
  • 3.3. A broad-range (0–35 ppt) and a subsequent narrow-range (9–16 ppt) salinity experiment with S2 larvae were used to identify 13 ppt as the optimal salinity, with 12 ppt as the next best; this agrees well with most previous estimates of optimal salinities for rearing larvae.
  • 4.4. S1 larvae were also tested in a narrow-range salinity experiment but were not used further because, unlike starved S2 larvae, they molted during the experiment.
  • 5.5. Identification of the optimal salinity was not affected by 50% daily water exchange or by bright light.
  • 6.6. Exposure of larvae to three different salinities—7, 13 and 19 ppt—during S1 influenced the width of the optimal salinity range for S2 larvae.
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7.
8.
  • 1.1. In a continuing investigation of phycocyanin-membrane surface interaction, fluorescence quenching experiments were performed with a mixture of two populations of fluorescence probe-encapsulated phospholipid bilayer vesicles in the presence and absence of phycocyanin.
  • 2.2. These membrane vesicles were prepared with 1,2-dimyristoyl phosphatidylcholine (DMPC), cholesterol and a probe molecule.
  • 3.3. A fluorophore was encapsulated in one population of membrane vesicles, while a quencher was encapsulated in another population of membrane vesicles.
  • 4.4. The result was compared with those of experiments in the presence of other biomolecules, including albumin, cytochrome c, hemoglobin, myoglobin or RNA.
  • 5.5. Interestingly, a one-third reduction of the fluorescence intensity was observed in the mixture of these two populations of membrane vesicles in phycocyanin's presence.
  • 6.6. In contrast, the other biomolecules caused no significant reduction in the fluorescence intensity.
  • 7.7. These findings were evidence of a phycocyanin-induced membrane perturbation.
  • 8.8. This was further demonstrated by a phycocyanin-induced change in the thermotropic behavior of DMPC vesicles, as measured by differential scanning microcalorimetry.
  • 9.9. Such a unique property of phycocyanin is believed to be associated with its known membrane surface-interacting character.
  • 10.10. A possible phycocyanin-modulated membrane-membrane interaction was discussed.
  相似文献   

9.
  • 1.1. Blood, liver, heart, testis, skin, eye, muscle and kidney samples were obtained from elephants (Loxodonta africana) in the Kruger National Park during a culling programme in April 1992.
  • 2.2. Gene products of 25 protein coding loci in L. africana were examined by horizontal starch-gel electrophoresis.
  • 3.3. Eighteen protein coding loci (72%) displayed monomorphic gel banding patterns whereas only seven (28%) displayed polymorphic gel banding patterns.
  • 4.4. Average heterozygosity values for adults, youngsters and the total population are respectively 0.058, 0.024 and 0.047.
  • 5.5. Relative gene diversities within and between populations are 84% and 16% respectively.
  • 6.6. Two population simulation programmes were utilized to predict the duration of the current variability present in this species, based on current genetic variation and gene transfer from one generation to the next.
  相似文献   

10.
  • 1.1. Occurrence of lesions induced in plasmid DNA by cis-DDP and by HA was quantified both as a transforming activity and as conformation integrity of supercoilcd pBR322 DNA. Fifty per cent decrease of the biological activity of plasmid DNA, not accompanied by measurable change of DNA conformation, was observed after a single exposure of DNA to cis-DDP (1 hr/37°C).
  • 2.2. HA induced conversion of supercoiled DNA to other topological forms in a dose-dependent manner.
  • 3.3. One- and two-strand DNA breaks were determined electrophoretically with high sensitivity. Cis-DDP exposed DNA relaxed at 30 times lower HA concentration compared to intact DNA.
  • 4.4. This effect may be connected with a local distortion of DNA structure at the cis-DDP—DNA bond, which makes possible high effectivity of HA-DNA interaction.
  • 5.5. On other hand, biological activity stayed at the 50% level despite breaks induced in DNA.
  • 6.6. This finding supports the idea that DNA breaks occur at the locations which were modified during the exposure of DNA to cis-DDP.
  • 7.7. The importance of the DNA structure during interaction with HA may be seen during HA-DNA interaction at heat-denaturation of supercoiled DNA. At this condition, the DNA breaks were induced at 100 times lower concentration of HA.
  • 8.8. We conclude, on the basis of these results and results published earlier, that local distortion of supercoiled DNA structure, which is caused by the cu-DDP bond, and the local DNA uncoiling caused by heat-denaturation are related to high HA-DNA reactivity.
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11.
  • 1.1. The development of Gallena mellonella is strongly affected by a low temperature of 18°C (the last instar persists for more than one year, instead of about 9 days at 30°C). At 18°C the last instar Galleria mellonella larvae respond to juvenilizing treatment—chilling stress or juvenile hormone analogue—with a very low percentage or no supernumerary moults, respectively.
  • 2.3. Experiments in which larvae subjected to such treatments were transferred from 18°C to 30°C and vice versa showed that for the realization of the larval programme after chilling stress application the higher (30°C) temperature is needed.
  • 3.4. In last instar larvae reared at 18°C there coexist very high juvenile hormone titre and high juvenile hormone esterase activity.
  • 4.5. This phenomenon which is found in both, chilled and unchilled larvae, is discussed.
  相似文献   

12.
Darwinian fitness   总被引:2,自引:0,他引:2  
The term Darwinian fitness refers to the capacity of a variant type to invade and displace the resident population in competition for available resources. Classical models of this dynamical process claim that competitive outcome is a deterministic event which is regulated by the population growth rate, called the Malthusian parameter. Recent analytic studies of the dynamics of competition in terms of diffusion processes show that growth rate predicts invasion success only in populations of infinite size. In populations of finite size, competitive outcome is a stochastic process--contingent on resource constraints--which is determined by the rate at which a population returns to its steady state condition after a random perturbation in the individual birth and death rates. This return rate, a measure of robustness or population stability, is analytically characterized by the demographic parameter, evolutionary entropy, a measure of the uncertainty in the age of the mother of a randomly chosen newborn. This article appeals to computational and numerical methods to contrast the predictive power of the Malthusian and the entropic principles. The computational analysis rejects the Malthusian model and is consistent with of the entropic principle. These studies thus provide support for the general claim that entropy is the appropriate measure of Darwinian fitness and constitutes an evolutionary parameter with broad predictive and explanatory powers.  相似文献   

13.
  • 1.1. Under denaturing conditions (SDS-PAGE) the two natural vitellins of Bacillus taxa released five different polypeptides (A1, A2, A3, B1, B2).
  • 2.2. A2 and B2 bands from the two bisexual species (B. rossius and B. grandii) were found to differ; furthermore a non-vitellin yolk protein characterizes the subsepecies B.g. benazzii.
  • 3.3. From gels and their densitometric scanning profiles it is clear that parental polypeptides are expressed in the thelytokous parthenogenetic hybrids (B. whitei, B. lynceorum) and in the hybridogenetic B. rossius-grandii benazzii.
  • 4.4. A comparative approach of vitellin patterns appears fully adequate for tracing phylogenetic relationships and recognizing cladogenetic events.
  相似文献   

14.
  • 1.1. We used protein gel-electrophoresis to investigate genetic heterogeneity at 33 protein coding loci in a total of 46 blue wildebeest (C. taurinus) kept under different management regimes.
  • 2.2. Average heterozygosity ranged from 2.14 to 4.3% and within-population differences accounted for 97.2% of total relative gene diversity.
  • 3.3. Comparatively little divergence was found between animals sampled from populations with very diverse population sizes and management histories, with the largest genetic distance estimated between any two populations being only 0.0021.
  • 4.4. We discuss our results with particular emphasis on the influence of management history on genetic diversity and divergence in C. taurinus.
  相似文献   

15.
  • 1.1. The toxicity of the fungicide benomyl to terrestrial enchytraeid species was tested under different conditions.
  • 2.2. Despite a relatively low acute response even to higher concentrations in agar media, sensitive effects were observed for cocoon production and hatching success at the recommended concentration for agricultural application (5.9 ppm in the test medium).
  • 3.3. These sublethal effects could be reconciled with population tests in larger quantities of soil: lower abundance was due to a very low number of juveniles in the benomyl-treated cultures.
  相似文献   

16.
  • 1.1. The modulation of lipid dynamics and lipid protein interactions were studied in rat brain synaptosomal plasma membranes (SPM) up to 24 hr after exposure to cadmium (Cd).
  • 2.2. The activity of acetylcholinesterase and adenylate cyclase showed a considerable decrease after 6 hr of Cd exposure, followed by a progressive increase up to 24 hr.
  • 3.3. SPM chemiluminescence showed a maximum decrease at 12 hr, demonstrating a considerable increase in lipid peroxidation.
  • 4.4. SPM of Cd-exposed animals showed a statistical significant increase in fluorescence anisotropy parameter [(r0/r) — 1]−1 at 18 and 24 hr compared to SPM of the control, indicating a decrease of membrane fluidity.
  相似文献   

17.
  • 1.1. The fatty-acid composition of the red and green forms of Actinia equina from the Black Sea have been determined by methods involving silver-ion HPLC and GC-MS.
  • 2.2. The fatty acid compositions of both forms of A. equina resemble those of most marine invertebrates. Substantial amounts of C20 and C22 polyunsaturated fatty acids were found.
  • 3.3. Balck Sea Actenia equina contains a large amount of plasmalogens, mainly phospotidylcholine and phosphatidylserine plasmalogens.
  • 4.4. The red form of A. equina contains more arachidonic acid in glycolipid fraction and more phosphatidylethanolamine and its plasmalogen, while the green from contains more sphingomyelin. These differences are an indication that the species A. equina can be divided into two subspecies—green and red.
  相似文献   

18.
  • 1.1. Myosin light chains and parvalbumins have been compared in several trunk and head muscles from small and large size barbels (Barbus barbus) living in river or reared in hatchery.
  • 2.2. These proteins isolated from white, red and ventricle fibres exhibit identical electrophoretic characteristics in the four batches.
  • 3.3. The slow fibre content and the parvalbumin distribution are generally similar in river and hatchery barbels of the same size but differ between small and large barbels within a population.
  • 4.4. Alterations of the mode of fertilization and breeding conditions do not modify the differentiation of myosin and parvalbumins in barbels.
  相似文献   

19.
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Highlights
  • •Interplay of epithelial cells and internalized S. aureus was dissected over 96 h.
  • •Surviving host cells contain nonreplicating bacteria that persists in the cytoplasm.
  • •Competition over resources triggers temporal metabolic changes.
  • •Metabolic adaptation of host and bacteria determines the outcome of infection.
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20.
  • 1.1. Oxygen binding capabilities of whole-blood and hemoglobin from the snake Thamnophis sirtalis were analyzed, at different temperatures and with various organic phosphate concentrations.
  • 2.2. In whole-blood, the Hb-Hb co-operativity increases at high oxygen saturation, and at high temperatures (20 and 30°C) at low saturations as well. The co-operativity is slightly in excess of 4.
  • 3.3. Half-saturation co-operatively in hemoglobin solutions increases significantly (0.2—0.4 units) on addition of ATP, but not when the temperature is raised.
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