Identification of some Populus deltoides Marsh. x P. nigra L. clones,developed in North America,with the aid of allozymes

Summary Horizontal starch gel electrophoresis was done to assay 10 enzyme systems in root tips of 14 Populus deltoides x P. nigra clones developed by controlled hybridization and selected in North America, and some clones sharing one or both parents. The genotypes of the clones were determined for 31 loci coding for 10 enzyme systems. The interclonal allozyme variability was controlled by 12 loci. Each of the 14 clones had unique 12-locus genotypes, thus could be distinguished from each other. The clones differed from each other on an average of 4.2 loci. The first two Principal Components from Principal Component Analysis of the clonal allozyme genotype data accounted for 48% of the total variation in the 12 variant loci. 6-Pgd-3, Per-2, 6-Pgd-1, Aco-1 and Per-1 were found to be the most discriminating loci for the clones. The ordination of the clones on Principal Component axes 1 and 2 was in general agreement with the origin of the clones.     

Cohen实分布函数

从Cohen定义的量子相空间中的分布函数的一般表达式出发,导出了一个依赖于参数γ的满足边缘条件的实分布函数.求出了谐振子基态和第一激发态的分布函数的表达式,并把γ=1时函数的图象和Wigner函数图象作了比较.     

热应激对奶牛血液流变学指标及血清无机离子浓度和酶活性的影响

将40头健康娟荷奶牛和荷斯坦奶牛分为2组,分别于冬季12月份(牛舍日平均气温10.35℃,温湿度指数为47.24)和次年夏季7月份(牛舍日平均气温31.07℃,温湿度指数为82.61)测定热应激对奶牛血液流变学指标及血清无机离子浓度和酶活性的影响.结果表明:除血沉外,全血比黏度、血浆比黏度、红细胞压积,荷斯坦奶牛、娟荷奶牛夏季都明显升高,与冬季间差异均极显著(P<0.01),但在夏季或冬季2个品种间差异不显著(P>0.05);血清K+浓度,娟荷奶牛冬季与夏季间差异显著(P<0.05),荷斯坦奶牛冬季与夏季间以及2个品种间差异不显著(P>0.05);热应激极显著降低血清Na+、Ca2+浓度(P<0.01),但夏季或冬季2个品种间差异不显著(P>0.05);血清C l-浓度,2个品种间及2个季节间差异均不显著(P>0.05);热应激显著升高谷丙转氨酶、碱性磷酸酶活性(P<0.05),但夏季或冬季2个品种间差异不显著(P>0.05);谷草转氨酶活性,冬季2个品种间差异显著(P<0.05),夏季2个品种间差异不显著(P>0.05).可见,全血比黏度,血浆比黏度,红细胞压积,血清Na+、Ca2+浓度和谷丙转氨酶、碱性磷酸酶活性与奶牛品种无关,与热应激程度关系密切.     

Catalytic activity and immunochemical quantification of hepatic cytochrome P-450 in β-naphthoflavone and isosafrol treated rainbow trout (Oncorhynchus mykiss)

In addition to catalytical assays, immunochemical techniques have recently been employed to measure induction of the cytochrome P-450 (P450) monooxygenase system in fish with polyaromatic hydrocarbons (PAH). In the present study, polyclonal antibodies were raised against rainbow trout P450IA1. Levels of rainbow trout P450IA1 determined using protein blotting- and ELISA procedures were compared with levels of 7-ethoxyresorufin-O-deethylase (7-EROD) activity in liver microsomes from rainbow trout. These comparisons showed that values of P450A1 were positively correlated (r=0.99 and r=0.97) with 7-EROD activities. In addition, the effects of isosafrol (ISF) or -naphthoflavone (NF) treatments on P450 levels in rainbow trout liver were investigated using immunochemical and catalytical methods. ISF treatment induced 7-EROD activity as well as 7-methoxycoumarin-O-demethylase-, 7-ethoxycoumarin-O-deethylase-, 7-propoxy-coumarin-O-depropylase and 7-butoxycoumarin-O-debutylase activities, although to a lesser extent, compared with the NF treatment. In contrast, immunochemical quantification of rainbow trout P450IA1 protein revealed a slightly different pattern. ISF appeared to be a weak inducer of P450IA1 in rainbow trout compared with NF. In addition, the degree of inhibition of 7-alkoxycoumarin-O-dealkylase activities in ISF microsomes differed from that measured in control- and NF microsomes. The discrepancies between catalytic and immunochemical estimates of rainbow trout P450IA1 in ISF treated fish in addition to differencs between specific inhibitory pattern by specific polyclonal antibodies raised against rainbow trout P450IA1, indicate that important differences exists between the responses induced by NF- and ISF treatments in the rainbow trout liver.Part of this work was presented at the 6th International Conference on Biochemistry and Biophysics of Cytochrome P-450, Vienna, Austria, July 3–8, 1988.     

Fish-management relationships in Israeli commercial fish farming

To analyse the relationships among fish species performance and management procedures, a database was built up with data from 31 fish farms during the period 1976–1987 (1673 observations) and analysed through multivariate statistics (factor analysis). The data include nurseries, grow-out and operational ponds with mono- and polycultures of common carp, Cyprinus carpio, tilapia hybrid, Oreochromis niloticus × O. aureus, silver carp, Hypophthalmichthys molitrix, and mullet, Mugil cephalus. The main conclusions include the following. (1) The highest total yields and best tilapia performances were obtained in polyculture ponds where tilapia was the main species. (2) The best carp performances occurred in grow-out polyculture ponds where carp was the main species. Carp performance was improved in polycultures with mullet and silver carp, irrespective of whether tilapia were present or not. (3) Carp and tilapia yields increased as the nutritional inputs (feed pellets, sorghum pellets, manure), pond size and culture duration increased. The effect of the nutritional input was not linear, but logarithmic. (4) Growth rate of common carp was more affected by total density and stocking size than that of tilapia. Better carp and tilapia growth occurred in grow-out ponds when stocked at large sizes and cultured during short periods, mainly when both species were present. (5) Carp growth varied with the geographical region and size of fish pond, being better in smaller than in larger ponds due to reduced access to natural benthic food in deep ponds.     

Antioxidant effect of dietary tocopherol and ascorbic acid on growth and survival of Litopenaeus vannamei postlarvae

The nutritional effect of vitamin E in dietsfor Litopenaeus vannamei postlarve (PL19)was investigated. Four formulated diets withdifferent combinations of -tocopherylacetate (-TA), ascorbic acid (AA) andhighly unsaturated fatty acids (HUFA) weretested, using four replicates.No significant differences in survival wereobserved among treatments after 34 days offeeding. However, shrimp fed with a dietcontaining 2% fish oil (low n-3 HUFA content),200 mg.kg^–1 -TA and100 mg.kg^–1 AA (diet H/E/C) showedsignificantly better growth than those fed adiet supplemented with 5% fish oil (high n-3HUFA content), 200 mg.kg^–1 -TA and100 mg.kg^–1 AA (diet H+/E/C). Shrimp fedwith a diet containing 5% fish oil,900 mg.kg^–1 -TA and100 mg.kg^–1 AA (diet H+/E+/C) showed a significantly higher tissue level of n-6 PUFAthan postlarvae fed diet H+/E/C. No definiteconclusion could be drawn about a possibleinteraction between -TA and AA, since acomparison of the diet containing 5% fish oil,200 mg.kg^–1 -TA and700 mg.kg^–1 AA (H+/E+/C+) and the dietH+/E/C did not show any significant differencesin any of the measured parameters. Theantioxidative status of the shrimp tissue(measured by means of the thiobarbituric acid(TBA) assay and expressed as nM malonaldehyde(MA) per gramme dry weight) was equal for alltreatments. Nevertheless, there was a slightlylower MA value with the diet H+/E/C+,indicating that AA may be an effectiveantioxidant in the aqueous phase and at thewater/lipid interface of the tissue. The tissuelevels of -T and AA were highlydependent on the amounts in diets and nocorrelation between -T and AAincorporation could be observed.     

Synthesis and regulation of 17α-hydroxy-20β-dihydroprogesterone in immature males of Oncorhynchus mykiss

Three experimental approaches were chosen to study the question if the progestin 17-hydroxy-20-dihydroprogesterone (1720OHP) is synthesised in testes of young Oncorhynchus mykiss, in which the absence of spermatozoa was verified histologically: first, in order to detect 20-hydroxysteroid dehydrogenase activity (20HSD), testes homogenates were incubated with ³H-labeled 17OHP.Metabolites were analysed by TLC, HPLC, and repeated crystallization to constant isotope ratios. One of the metabolites was identified as 1720OHP-³H, indicating that already immature testes contain 20HSD activity and are able to produce 20-reduced steroids. Second, 1720OHP was quantified by radioimmunoassay in incubates of testes fragments. The sensitivity of the gonads to gonadotropin II (GtH II) became evident when comparing incubations in the absence and presence of GtH II. Third, plasma levels of 1720OHP were significantly higher in animals injected with partially purified salmon gonadotropin, compared to controls. Thus, for the first time, it could be shown that 20HSD is present in testicular cells other than spermatozoa. Furthermore, 1720OHP is indeed secreted at a very early stage of testicular development; 1720OHP secretion is also responsive to GtH II. Future studies will have to show if the functions of this progestin include the stimulation of spermatogenesis.     

巨尾桉林地土壤化学性质变化分析

通过对福建省长泰县一块巨尾桉林地18 a经营前后土壤各种养分指标的比较,揭示桉树林地长期经营对土壤肥力的影响,结果表明：土壤有机质、养分全量及交换性钙、镁、碱解氮等都有不同程度提高,而速效钾、pH值和速效磷等有所降低,分析认为杂交桉主要靠杂交优势而非靠消耗地力获得增产,杂交桉林地养分循环良好,土壤有机质增加,土壤供肥潜力提高;现有速效钾、pH值为林地正常值,18 a前测定的为炼山造林后的样品数据,草木灰（K2CO3）渗入土壤所致,速效磷降低为杂交桉对其需求量较大所致;建议在桉树人工林经营过程中应注意补充磷肥和钙肥。     

Genetic resources in apple,pear and vineyard peach populations in former Yugoslavia

Summary During the period 1988–90, several germplasm collecting trips were made to all republics of former Yugoslavia. A total of 56 old apple cultivars, many of which are represented in up to 5 types, 38 old pear cultivars and 367 genotypes of vineyard peaches were collected. The availability of so much genetic and genotypic wealth made it possible to start apple disease resistance breeding and peach cultivar and rootstock breeding programmes.     

Analysis of genotypic and environmental variation in international mungbean trials

Summary Two-way classification analysis, combined with analysis of variance and linear regression techniques, was applied to a set of yield data from twenty-one genotypes grown at twelve locations for two years in International Mungbean Nursery trials. Genotypes and environments with similar yield response patterns were grouped and differences between groups identified. Genotypes were also grouped on the basis of flowering time and the relation between days to flower and yield was examined. It was concluded that cluster and associated analyses are of value in determining response patterns of mungbean genotypes to a wide range of environments, and a useful aid in the selection of materials and locations for mungbean evaluation. In particular we note the adaptation of genotypes M409 and M1134 to high elevation locations, and the positive yield response of M374 (MG50-10A) to high yielding environments. Highest yielding lines were also the earliest to flower. Disease resistance was considered the most important breeding objective for mungbean yield improvement.