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71.
Fluctuating asymmetry (FA) has been used as a measure of developmental stability and may indicate individual phenotypic or genotypic quality. Using water boatmen (Callicorixa vulnerata) from a natural population, we examined the relationship between tarsal FA (tarsal spine number, tarsal length) and indices of body condition in two habitats. We used body weight and residual body weight (controlling for body length) as indices of condition because experimental food deprivation in water boatmen led to a reduction in each. We detected a negative relationship between FA and both indices of condition in two ecologically distinct pond habitats. We predicted this association was due to a negative relationship between FA and competitive feeding ability. Consequently, we examined associations between survival time and tarsal FA in C. vulnerata under resource-limited laboratory conditions. Univariate analyses revealed a negative correlation between survival and tarsal FA in each trait. Inclusion of survival time, body length, gender, tarsal spine number, tarsal length, and measures of FA into multivariate analyses revealed a negative correlation between survival and FA. Individuals with the greatest survival had higher nutritional condition than individuals that succumbed early in the experiment. Asymmetric individuals may suffer a foraging handicap as a result of the use of tarsi in feeding or they may be of poor genetic quality. Our results suggest elevated FA may limit resource acquisition and are consistent with the use of FA as a measure of fitness. 相似文献
72.
Background
Dynamic Flux Balance Analysis (DFBA) is a dynamic simulation framework for biochemical processes. DFBA can be performed using different approaches such as static optimization (SOA), dynamic optimization (DOA), and direct approaches (DA). Few existing simulators address the theoretical and practical challenges of nonunique exchange fluxes or infeasible linear programs (LPs). Both are common sources of failure and inefficiencies for these simulators.Results
DFBAlab, a MATLAB-based simulator that uses the LP feasibility problem to obtain an extended system and lexicographic optimization to yield unique exchange fluxes, is presented. DFBAlab is able to simulate complex dynamic cultures with multiple species rapidly and reliably, including differential-algebraic equation (DAE) systems. In addition, DFBAlab’s running time scales linearly with the number of species models. Three examples are presented where the performance of COBRA, DyMMM and DFBAlab are compared.Conclusions
Lexicographic optimization is used to determine unique exchange fluxes which are necessary for a well-defined dynamic system. DFBAlab does not fail during numerical integration due to infeasible LPs. The extended system obtained through the LP feasibility problem in DFBAlab provides a penalty function that can be used in optimization algorithms.Electronic supplementary material
The online version of this article (doi:10.1186/s12859-014-0409-8) contains supplementary material, which is available to authorized users. 相似文献73.
Nicola Bryson-Morrison Andy Beer Aly Gaspard Soumah Tetsuro Matsuzawa Tatyana Humle 《American journal of primatology》2020,82(3):e23102
Agricultural expansion encroaches on tropical forests and primates in such landscapes frequently incorporate crops into their diet. Understanding the nutritional drivers behind crop-foraging can help inform conservation efforts to improve human-primate coexistence. This study builds on existing knowledge of primate diets in anthropogenic landscapes by estimating the macronutrient content of 24 wild and 11 cultivated foods (90.5% of food intake) consumed by chimpanzees (Pan troglodytes verus) at Bossou, Guinea, West Africa. We also compared the macronutrient composition of Bossou crops to published macronutrient measures of crops from Bulindi, Uganda, East Africa. The composition of wild fruits, leaves, and pith were consistent with previous reports for primate diets. Cultivated fruits were higher in carbohydrates and lower in insoluble fiber than wild fruits, while wild fruits were higher in protein. Macronutrient content of cultivated pith fell within the ranges of consumed wild pith. Oil palm food parts were relatively rich in carbohydrates, protein, lipids, and/or fermentable fiber, adding support for the nutritional importance of the oil palm for West African chimpanzees. We found no differences in the composition of cultivated fruits between Bossou and Bulindi, suggesting that macronutrient content alone does not explain differences in crop selection. Our results build on the current understanding of chimpanzee feeding ecology within forest-agricultural mosaics and provide additional support for the assumption that crops offer primates energetic benefits over wild foods. 相似文献
74.
75.
Abstract: Because of significant declines in mule deer (Odocoileus hemionus) populations across New Mexico, USA, we investigated survival of fawns in north-central New Mexico, USA. We captured 19 fawns, 34 fawns, and 47 fawns in 2002, 2003, and 2004, respectively, and used fawn morphological measurements, habitat characteristics, and adult female (hereafter “female”) condition to model preweaning fawn survival. Survival was 0.0, 0.12, 0.52 for 2002, 2003, and 2004, respectively, and was related to birth mass (χ12 = 9.5, P = 0.002), birth date (χ12= 8.4, P = 0.004), litter size (χ22 = 9.4, P = 0.009), female body fat (χ12 = 40.9, P < 0.001), annual precipitation (χ12 = 35.0, P < 0.001), summer precipitation (χ12= 37.5, P < 0.001), and winter precipitation (χ12 = 32.0, P < 0.001). Total ingesta-free body fat of females (β = 3.01, SE = 0.75; odds ratio = 20.19, 95% CI = 4.64-87.91) and birth mass of fawns (β = 1.188, SE = 0.428; odds ratio = 3.38, 95% CI = 1.42-7.59) were the best predictors of survival of individual fawns, although few of the logistic models differed in model selection criteria. Fawn survival in north-central New Mexico was driven by an interaction of total and seasonal precipitation and its effect on plant production, consequential effects on female nutrition, and ultimately, fawn birth attributes. Habitat conditions were so poor throughout north-central New Mexico during 2002 and 2003 (and likely during other drought yr) that, based upon birth attributes, few fawns could have survived regardless of proximate causes of mortality. In 2004, precipitation enhanced security cover, maternal body condition, birth attributes and, thus, survival of fawns. However, more habitat enhancements are needed to improve the nutritional quality of mule deer habitats in north-central New Mexico and further enhance maternal and fawn condition to recover mule deer populations in this region. 相似文献
76.
Joshua P. Moatt Murray A. Fyfe Elizabeth Heap Luke J. M. Mitchell Fiona Moon Craig A. Walling 《Aging cell》2019,18(1)
Dietary restriction (DR) is one of the main experimental paradigms to investigate the mechanisms that determine lifespan and aging. Yet, the exact nutritional parameters responsible for DR remain unclear. Recently, the advent of the geometric framework of nutrition (GF) has refocussed interest from calories to dietary macronutrients. However, GF experiments focus on invertebrates, with the importance of macronutrients in vertebrates still widely debated. This has led to the suggestion of a fundamental difference in the mode of action of DR between vertebrates and invertebrates, questioning the suggestion of an evolutionarily conserved mechanism. The use of dietary dilution rather than restriction in GF studies makes comparison with traditional DR studies difficult. Here, using a novel nonmodel vertebrate system (the stickleback fish, Gasterosteus aculeatus), we test the effect of macronutrient versus calorie intake on key fitness‐related traits, both using the GF and avoiding dietary dilution. We find that the intake of macronutrients rather than calories determines both mortality risk and reproduction. Male mortality risk was lowest on intermediate lipid intakes, and female risk was generally reduced by low protein intakes. The effect of macronutrient intake on reproduction was similar between the sexes, with high protein intakes maximizing reproduction. Our results provide, to our knowledge, the first evidence that macronutrient, not caloric, intake predicts changes in mortality and reproduction in the absence of dietary dilution. This supports the suggestion of evolutionary conservation in the effect of diet on lifespan, but via variation in macronutrient intake rather than calories. 相似文献
77.
两个菜用枸杞品种的生长特性及品质分析 总被引：2，自引：0，他引：2
对两个菜用枸杞品种的主要生长特性、营养成分及食用性研究表明,大叶品种嫩芽平均产量显著高于小叶品种;大叶品种较耐高温,小叶品种较耐低温;生产上可进行大、小叶品种搭配种植,能有效提早和延长采收期,从而提高单位面积产量和经济效益。此外,小叶品种嫩芽的蛋白质、VitC含量高于大叶品种。两个品种风味各具特色,其适宜的消费群体亦有所差异。 相似文献
78.
Changes in the concentrations of phytochemical compounds usually occur when plants are grown under elevated atmospheric CO2. CO2-induced changes in foliar chemistry tend to reduce leaf quality and may further affect insect herbivores. Increased atmospheric CO2 also has a potential influence on decomposition because it causes variations in chemical components of plant tissues. To investigate the effects of increased atmospheric CO2 on the nutritional contents of tree tissues and the activities of leaf-chewing forest insects, samples of Populus pseudo-simonii [Kitag.] grown in open-top chambers under ambient and elevated CO2 (650 μmol mol-1) conditions were collected for measuring concentrations of carbon, nitrogen, C : N ratio, soluble sugar and starch in leaves, barks, coarse roots (>2 mm in diameter) and fine roots (<2 mm in diameter). Gypsy moth (Lymantria dispar) larvae were reared on a single branch of experimental trees in a nylon bag with 1 mm 1 mm grid. The response of larval growth was observed in situ. Elevated CO2 resulted in significant reduction in nitrogen concentration and increase in C : N ratio of all poplar tissues. In all tissues, total carbon contents were not affected by CO2 treatments. Soluble sugar and nonstructural carbohydrate (TNC) in the poplar leaves significantly increased with CO2 enrichment, whereas starch concentration increased only on partial sampling dates. Carbohydrate concentration in roots and barks was generally not affected by elevated CO2, whereas soluble sugar contents in fine roots decreased in response to elevated CO2. When second instar gypsy moth larvae consuming poplars grew under elevated CO2 for the first 13 days, their body weight was 30.95% lower than that of larvae grown at ambient CO2, but no significant difference was found when larvae were fed in the same treatment for the next 11 days. Elevated atmospheric CO2 had adverse effects on the nutritional quality of Populus pseudo-simonii [Kitag.] tissues and the resultant variations in foliar chemical components had a significant but negative effect on the growth of early instar gypsy moth larvae. 相似文献
79.
80.
Gymnodinium catenatum Graham is an unarmored, cyst‐forming dinoflagellate species responsible for outbreaks of paralytic shellfish poisoning. The nuclear development of the cells during the sexual cycle and the effect of different nitrate and phosphate external levels on sexual stages were studied. Nuclear fusion of gametes occurred before or at the same time as cytoplasmic fusion. During this process, either both nuclei migrated to a central area in the sulcal region, or only one of them migrated to the other nucleus. The motile and longitudinally biflagellated zygote presented a large, pear‐shaped nucleus, and either divided or encysted. Planozygotes and germlings underwent similar division processes, which suggested an uncoordinated meiosis in both encysting and non‐encysting zygotes. Encystment in culture was greater under low nitrate and phosphate limitation (L/15) than when only one or neither of these nutrients were added (L‐N, L‐P, and ‐N‐P). However, planozygotes individually monitored achieved the maximum encystment (40%) in a medium with no phosphate or nitrate added (‐N‐P), while most of them divided (70%–90%) in replete (L1) or half‐replete (L‐N and L‐P) media. Low levels of nitrate in the medium of cyst formation promoted a deficient development of the cyst wall. On the other hand, low phosphate levels in the medium of germination prevented both planozygote and germling division and lowered the final germination frequencies of cysts. The minimum dormancy, with an average value of 13.7±5.5 days, was not affected by any of the nutritional conditions studied. 相似文献