Duration of the breeding season and response to reproductive manipulation in five breeds of sheep under northern prairie conditions

The breeding season was 157, 154, <126, 210 and 217 days for Rambouillet, Columbia, Suffolk, Rambouillet x Finnish Landrace and Columbia x Finnish Landrace ewes respectively. Treatment of cyclic ewes with pregnant mare serum gonadotropin (PMSG) (500 IU), following a 12-day treatment with progestin-containing intravaginal sponges, did not affect fertility, but did decrease the time from sponge removal to estrus, (control 48.0 +/- 3.1 hr; PMSG 39.4 +/- 1.8 hr) to the preovulatory surge of LH (control 52.7 +/- 2.8 hr; PMSG 39.0 +/- 1.7 hr) and FSH (control 52.3 +/- 2.9 hr; PMSG 42.8 +/- 1.6 hr) and caused an elevation of serum LH levels prior to the preovulatory surge (control 1.25 +/- 0.18 ng/ml; PMSG 2.31 +/- 0.22 ng/ml). Exposure of the purebred ewes to 18 hours of daylight in January, decreasing by 30 minutes a week subsequently, counteracted the seasonal reduction in the number of ewes lambing following induced breeding under natural daylight in May. Prolificacy was greatest in crossbred ewes and their fertility was not affected by season. Gestation period was longer for fall-bred ewes and varied with breed.     

Aggression in adult male primates: A comparison of confined Japanese macaques and free-ranging olive baboons

The frequencies and types of adult male aggressive behavior of confined Japanese macaques (Macaca fuscata)and free-ranging olive baboons (Papio anubis)were compared. The baboons, which do not have a mating season, were more aggressive to conspecific males than were the macaques during their nonmating season. The baboons also solicited aid during aggressive encounters more frequently than the macaques. However, during their mating season, the macaques were more aggressive to conspecific females than were the baboons. The macaques were also involved in more triadic sequences of aggression, and the frequency of occurrence of these patterns supported Chase’s theory of dominance hierarchy formation and maintenance. The differences in aggressive behavior appeared to be related to the seasonal reproductive cycle of the macaques.     

Pattern of dry-matter accumulation,and nitrogen concentration and uptake as influenced by levels and methods of nitrogen application in rainfed-upland rice

Summary Dry-matter accumulation, and concentration and uptake of nitrogen increased with increasing level of nitrogen at all the stages of crop growth. The differences in nitrogen concentration due to nitrogen levels were greatest at panicle initiation stage and started becoming narrower with the advancement in crop age. Split application of nitrogen with its heavier fractions at tillering and panicle initiation stages either through soil alone or soil+foliage (1/3+1/3+1/3) resulted in higher dry-matter accumulation, and higher nitrogen concentration and uptake than other methods. The crop, on an average, removed 61 kg N/ha. Plants accumulated nearly 15% of the total absorbed nitrogen, up to tillering, 50% up to panicle initiation and 85–90% up to heading. Proportionately lesser nitrogen uptake and dry-matter accumulation at post-heading stage is an indicative of a major constraint for production efficiency of rainfed-upland rice culture.     

Spawning and nesting behavior of the waccamaw darter,Etheostoma perlongum

Synopsis The spawning and nesting behavior ofEtheostoma (Boleosoma) perlongum was investigated in the field and laboratory. Sexual dimorphism is highly developed in such features as genital papillae, first dorsal and paired fins, and nuptial coloration. A reproductive migration from mid-lake to shore occurs in the spring: males precede females to select nest sites under submerged sticks and other debris. The male excavates a depression beneath the submerged object. Gonad analysis indicates a single spawning season extending from March through June. Nests were found from late April to mid-June and were guarded by a single male for periods of 13 to 36 days. Males initiate courtship by lateral display, lead the female to the nest site and show the nest by inverting. The female responds by tail up, tail wag and circle; males also tail wag and circle. Spawning pairs invert, usually in unison, and orient head to head or, less often, head to tail. The female deposits eggs while holding her body in a weak S or J shape with the caudal peduncle held away from the spawning substrate while vibrating.     

麦草栽培姬菇配方的数学模型研究

借助二次通用旋转组合设计法研究了麦草栽培姬菇配方的数学模型,以探讨利用麦草替代棉籽壳的新配方.试验结果得出了配料的取值范围及最佳栽培配方,即麦草79％,麸皮15％,玉米粉4％,过磷酸钙1％,黄豆饼粉1％.在实际生产中很有应用价值.     

固定化生长酵母连续生产酒精的研究中间试验报告

造粒器与柱式生物反应器成—封闭系统,采用正交试验确定的最适固定化条件,以海藻酸钙凝胶法进行细胞固定化,连续造粒,在反应器中完成固定化。固定化酵母在反应器中通气培养20小时左右,凝胶球细胞数达2×10~9/me,其增长速度比传统工艺自然细胞快10倍。固定化生长细胞用于生物反应器连续发酵甜菜糖蜜酒精,酒精生产能力为22.1—23.67g/L凝胶球/小时,为传统工艺酒精生产能力的10倍。停留时间为3小时。反应器系统由两个0.7KL柱式反应器和1个0.8KL成熟醪接收器组成。发酵周期由传统工艺的20小时左右,缩短为4小时,酒精含量为8.5—9.0％(V/V),对1.2号反应器的动态变化及其在发酵中的作用进行了系统研究,糖蜜中可发酵糖75％的转化是在1号反应器中完成的。     

Drought acclimation among tropical forest shrubs (Psychotria,Rubiaceae)

Summary Mechanisms of dry-season drought resistance were evaluated for five evergreen shrubs (Psychotria, Rubiaceae) which occur syntopically in tropical moist forest in central Panama. Rooting depths, leaf conductance, tissue osmotic potentials and elasticity, and the timing of leaf production were evaluated. From wet to dry season, tissue osmotic potentials declined and moduli of elasticity increased in four and five species, respectively. Irrigation only affected osmotic adjustment by P. furcata. The other seasonal changes in leaf tissue properties represented ontogenetic change. Nevertheless, they made an important contribution to dry-season turgor maintenance. Small between-year differences in dry season rainfall had large effects on plant water status. In 1986, 51 mm of rain fell between 1 January and 31 March, and pre-dawn turgor potentials averaged <0.1 MPa for all five Psychotria species in March (Wright 1991). In 1989, 111 mm of rain fell in the same period, pre-dawn turgor potentials averaged from 0.75 to 1.0 MPa for three of the species in April, and only P. chagrensis lost turgor. The relation between leaf production and drought differed among species. P. limonensis was buffered against drought by the lowest dry-season conductances and the deepest roots (averaging 244% deeper than its congeners) and was the only species to produce large numbers of leaves in the dry season. P. chagrensis was most susceptible to drought, and leaf production ceased as turgor loss developed. For the other species, water stress during severe dry seasons may select against dry-season leaf production.     

Relationship between excision repair and the cytotoxic and mutagenic effect of the ‘anti’ 7,8-diol-9,10-epoxide of benzo[a]pyrene in human cells

The cytotoxic and mutagenic effect of (±)-7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti BPDE) in normally excision diploid human cells treated just prior to onset of S was compared with that of cells allowed ～ 16 h for excision repair before onset of S and with that observed in excision-deficient serodema pigmentosum (SP12BE) cells. The cells were synchronized by release from density inhibition of cell replication. DNA synthesis began ～ 22 h after the cells were plated at lower density (i.e., 1.4 × 10⁴ cells/cm²). The frequency of thioguanine-resistant mutants induced in normal cells treated just prior to onset of S was ～ 12- to 16-fold higher than that observed in cells treated in early G₁ or treated in G₀ (confluence) and then plated at lower density. The frequency approximated that expected for XP12BE cells from extrapolation of data obtained at lower doses. The frequency of mutants measured in normal cells treated in exponential growth was also much higher than that in the cells treated in early G₁ or in G₀, No such difference could be seen in XP12BE cells treated in exponential growth or in G₀. In contrast to the mutagenicity data in the normal cells, there was no significant difference in the slope of the survival curve of normal cells treated at various times prior to S phase at low densities. However, normal cells treated even at the onset of S exhibited survival equal to XP12BE cells give a 4- to 5-fold lower dose. The data support the hypothesis that DNA synthesis is the cellular event which converts unexcised DNA lesions into mutations. However, they indicate that S is not the event primarily responsible for translating DNA damage into cell death. Accompanying studies on the rate of excision of anti BPDE adducts from the normal cells during the period priot to S support the conclusions.     

Regulation of amino acid transport in growing cells of Streptomyces hydrogenans

The uptake of various amino acids into Streptomyces hydrogenans grown in chemostatically and turbidostatically controlled steady state cultures has been investigated. A close correlation between transport capacity and the growth rates of the cells was found. As shown by kinetic analysis, the increased transport is due to elevated maximum uptake rates, the apparent Michaelis constants remaining unchanged. Analysis of the unidirectional fluxes of cycloleucine revealed that not only the influx is raised as the growth rate is increased but also the efflux. Hence, the conclusion is drawn that the growth-rate dependent modulation of transport capacity is, at least, partially due to the variation of the concentration of active transport components. Since the cells were grown in the absence of external amino acids the results suggest that amino acid transport into S. hydrogenans is under the control of endogenous effectors.List of Abbreviations AIB 2-aminoisobutyric acid - Cycloleucine 1-aminocyclopentane-1-carboxylic acid