Clutch size, offspring performance, and intergenerational fitness

It is now generally recognized that clutch size affects morethan offspring number. In particular, clutch size affects asuite of traits associated with offspring reproductive performance.Optimal clutch size is therefore determined not by the numericallymost productive clutch but by the clutch that maximizes collectiveoffspring reproductive success. Calculation of optimal clutchsize thus requires a consideration of ecological factors operatingduring an intergenerational time frame, spanning the lifetimeof the egglaying adult and the lifetimes of her offspring. Theoptimal clutch cannot define reproductive values in advance,but instead requires that the strategy chosen is the best responseto the set of reproductive values that it itself generates.In this article, we introduce methods for solving this problem,based on an iterative solution of the equation characterizingexpected lifetime reproductive success. We begin by consideringa semelparous organism, in which case lifetime reproductivesuccess is a function only of the state of the organism. Foran iteroparous organism, lifetime reproductive success dependsupon both state and time, so that our methods extend the usualstochastic dynamic programming approach to the evaluation oflifetime reproductive success. The methods are intuitive andeasily used. We consider both semelparous and iteroparous organisms,stable and varying environments, and describe how our methodscan be employed empirically.     

23个实验小鼠和大鼠近交系的保种研究

从1985年开始,陆续从国外实验动物著名机构引进常用近交系小鼠共23个品系(亚系和亚群)。在多年来保种繁殖过程中,根据修饰平行线系统选择留种动物,同时对动物进行全兄妹近亲交配繁殖,保持完整的谱系记录,控制饲养环境条件,成功地保持了绝大多数品系。同时对多数品系的繁殖性能和体重增长进行了观察,为这些品系的实验应用提供基本参数。     

Identification of Products from Oxidation of Uric Acid Induced by Hydroxyl Radicals

The aim of the present study was to separate and characterise products formed by oxidation of uric acid by hydroxyl radicals with a view to probing for these products in vivo in clinical contexts. Aerated solutions of 200 μM uric acid, or its oxidation products, allantoin or parabanic acid, were exposed to gamma radiolysis, (52.0 Gy/min), as a source of HO- radicals, at pH 3.4 and 7.4. Aliquots were taken every 5 minutes for 20 minutes and oxidation products were separated by HPLC and analysed with a diode array detector. Identities of oxidation products were confirmed on the basis of similarity of retention times and absorbance spectra and peak purity parameters of known standards. Hydroperoxides were measured by tri-iodide formation in the 20 minute sample. Exposure of uric acid to such HO fluxes produced a net loss of the parent compound with formation of a complex mixture of products with allantoin and parabanic acid being the predominant products at pH 3.4. The rate of uric acid degradation at physiological pH was slower and the distribution of oxidation products was different. A small but significant amount of uric acid hydroperoxide was detected at both pHs. A mechanism for uric acid oxidation under these conditions is presented.     

Reproductive status of cheetahs (Acinonyx jubatus) in North American Zoos: The benefits of physiological surveys for strategic planning

Under the mandate of a Species Survival Plan (SSP), reproductive status was assessed in 128 cheetahs maintained in 18 different institutions in North America. A mobile laboratory research team evaluated cheetahs using anesthesia, serial blood sampling, electroejaculation (males), and laparoscopy (females). Biomaterials were also collected for parallel studies of genetics, nutrition, and health. There was no mortality, and cheetahs were capable of reproducing naturally after these intense manipulatory examinations. No marked differences were observed in reproductive or endocrine characteristics between proven and unproven breeders. However, males consistently produced teratospermic ejaculates, and cheetah sperm were compromised in conspecific or heterologous in vitro fertilization systems. Structurally abnormal sperm were found to be filtered by the oocyte's zona pellucida. More than 80% of the females were anatomically sound, but morphological and endocrine evidence suggested that ～50% or more of the population may have had inactive ovaries at the time of the examination. Males ranging in age from 15 to 182 months produced spermic ejaculates, but motile sperm numbers/ejaculate and circulating testosterone concentrations were highest in males 60 to 120 months old. Parovarian cysts were observed in 51.5% of female cheetahs, but comparisons between proven and unproven subpopulations revealed that this abnormality likely had no influence on fertility. Fresh luteal tissue was not observed in any nonpregnant or nonlactating female, strongly suggesting that the cheetah is an induced ovulator. Overall survey results were discussed in the context of the etiology of reproductive inefficiency, especially with respect to the potential importance of biological versus management factors. Four high priority research areas in cheetah reproductive biology were identified: 1) continuous monitoring of ejaculate quality in the extant population, while studying the impact of pleiomorphisms on fertility; 2) determining the potential relationship between libido and androgen production (excretion) in males; 3) confirming the extent of cyclic, or acyclic, ovarian activity in females; and 4) continued development of assisted reproductive techniques for enhancing man-agement. In summary, a multidisciplinary, multi-institutional survey coordinated through the SSP is both possible and useful for generating a physiological and health database beneficial to driving further research and management initiatives. © 1993 Wiley-Liss, Inc.     

Comparison between cellulose and amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phases for enantiomeric separation of 17 amidotetralins

Direct enantiomeric separations of 17 chiral amidotetralins by means of high performance liquid chromatography were performed on stationary phases composed of tris(3,5-dimethylphenylcarbamate) derivatives of cellulose and amylose, coated on silica gel. The enantiomers of 15 out of 17 amidotetralins were resolved with a resolution of more than 1.5 by at least one of the chiral stationary phases. The stationary phases showed complementary results with regard to the separation of the amidotetralins, that is, pairs that did not separate on the cellulose-type column were well separated on the amylose-type column, and vice versa. There was no significant correlation between the chromatographic properties of the chiral stationary phases. © 1993 Wiley-Liss, Inc.     

iBench: A ground truth approach for advanced validation of mass spectrometry identification method

The discovery of many noncanonical peptides detectable with sensitive mass spectrometry inside, outside, and on cells shepherded the development of novel methods for their identification, often not supported by a systematic benchmarking with other methods. We here propose iBench, a bioinformatic tool that can construct ground truth proteomics datasets and cognate databases, thereby generating a training court wherein methods, search engines, and proteomics strategies can be tested, and their performances estimated by the same tool. iBench can be coupled to the main database search engines, allows the selection of customized features of mass spectrometry spectra and peptides, provides standard benchmarking outputs, and is open source. The proof-of-concept application to tryptic proteome digestions, immunopeptidomes, and synthetic peptide libraries dissected the impact that noncanonical peptides could have on the identification of canonical peptides by Mascot search with rescoring via Percolator (Mascot+Percolator).     

THE FUNCTIONAL BASIS OF NATURAL SELECTION FOR VERTEBRAL TRAITS OF LARVAE IN THE STICKLEBACK GASTEROSTEUS ACULEATUS

Previous studies have demonstrated selective predation for vertebral traits of larvae in the stickleback Gasterosteus aculeatus. I tested the hypothesis that this selection results from a direct functional advantage to particular vertebral phenotypes by direct measurement of the burst swimming performance of larvae. Within a narrow window of lengths, burst speed did depend on vertebral phenotype. As in the previous predation experiments, performance was related more directly to the ratio of abdominal to caudal vertebrae (VR) than to the total number of vertebrae (VN), and the optimal VR decreased as larval length increased. Changes with length in the vertebral phenotype frequencies of wild larvae provided evidence of selection for VR and for VN in the wild. Larvae with particular VR increased in frequency in the wild at just those lengths when their relative performance was superior in the laboratory. The observed pattern of length-dependent selection for vertebral number provides an explanation for the widespread trends in vertebral number that occur among populations of related fishes.     

Plant preference in relation to life history traits in the zoophytophagous predator Dicyphus hesperus

Dicyphus hesperus Knight (Heteroptera: Miridae) is an omnivorous predator used to control pests of greenhouse vegetables. Plant preferences and life history traits were studied using nine plant species: Lycopersicon esculentum Mill. (Solanaceae), Capsicum annuum L. (Solanaceae), Verbascum thapsus L. (Scrophulariaceae), Nepeta cataria L. (Lamiaceae), Stachys albotomentosa (Lamiaceae), Nicotiana tabacum L. (Solanaceae), Vicia sativa L. (Fabaceae), Zea mays L. (Gramineae), and Chrysanthemum coronarium L. (Asteraceae). Plants were selected from among potential target crops, natural hosts, plants used for mass rearing, and plants on which D. hesperus has not been reported. Plant preference was measured by multi‐choice host plant selection and oviposition assays. Development and reproduction were measured on each of the plant species on both a plant diet alone and on a plant diet supplemented with Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs. Dicyphus hesperus females and nymphs expressed a preference for some plants over others. Plant preference ranged from low preference plants, such as Z. mays, V. sativa, C. coronarium, and C. annuum, to high preference plants such as V. thapsus, N. tabacum, and S. albotomentosa. When E. kuehniella eggs were supplied, there were few differences in the development time and fecundity of D. hesperus among plants, with the exception of corn and broad bean, where fecundity was lower. On a plant diet alone, nymphs were able to complete their development on V. thapsus, C. annuum, and N. cataria. However, mortality and development time were much lower on V. thapsus than on C. annuum and N. cataria. On most of the plant species D. hesperus did not lay any eggs when fed on a plant diet alone. On V. thapsus, females laid a few eggs and lived longer than when fed on prey. Dicyphus hesperus females tended to prefer host plants on which nymph survival without prey was greatest.     

褐飞虱、白背飞虱种间、种内密度制约效应研究

以高感品种TN1为材料．研究了褐飞虱、白背飞虱成、若虫密度对种群的制约效应。实验表明,单虫种一龄善虫密度15头／株和30头／株相比．褐飞虱成虫的羽化率、短翘率、体长和若虫历期均无明显差异,但成虫雌性比率前高;白背飞虱成虫羽化率前比后高21．22％．短翘率高15.25％。在两种飞虱一龄若虫密度30、45、60头／株等虫量混合组配下,褐飞虱成虫羽化率60头／株比30头／株下降28％,白背飞虱若虫历期以30头／株最长。在总虫量为30头／株时,种内(30头／株)和种间(15：15头／株)比．白背飞虱种内处理成虫羽化率高36．83％．昔虫历期短;褐飞虱以种内处理成虫短翘率高。从产卵位点来看．褐飞虱喜产在稻株叶鞘中下部厚肉组织上,白背飞虱以叶脉基部产卵为主．成虫密度2、4、8对／株3处理,其叶鞘、叶脉上的平均卵块变小;10天内的平均卵量亦减步。同密度下,种间组合比种内组合的产卵量多。从各指标对密度反应来看,褐飞虱比白背飞虱更耐拥挤。