Bilirubin excretion and bile flow in fed and fasted Brazilian squirrel monkeys (Saimiri sciureus)

Fasted Brazilian squirrel monkeys (BrSMs) exhibited slightly higher serum bilirubin levels (0.30±0.05 mg/dl) than others in the fed state (0.13±0.01). The mean liver weight was 50% lower following a 22 h fast. The rate of bile flow was unaffected by fasting and averaged 13.8 l/min/kg and 47.5 l/min/100g liver in six BrSMs. No significant difference in mean bilirubin excretion/min was observed on a body weight basis following fasting. When the mean rate of bilirubin excretion was calculated as a function of liver weight, a two-fold higher rate was present in fasted monkeys, but only at the p=0.06 level of statistical significance. From data collected in this and earlier studies, it would appear that BrSMs represent the best animals studied to date to serve as experimental controls in comparative studies with Bovilian squirrel monkeys which exhibit a Gilbert-like syndrome.     

Permeability of the endothelium and partitioning of the pulmonary blood flow resistance in isolated perfused pig lungs: Effects of breed and age

The right and left lungs of 5 healthy Minipigs and of 13 healthy Landrace piglets were isolated, perfused at constant pressure and maintained in an isogravimetric state under zone III conditions (pulmonary venous pressure>alveolar pressure). By applying the double, arterial and venous, occlusion technique, the total blood flow resistance (R _t) was partitioned into four components: arterial (R _a), pre-(R _a) and post-capillary (R _v) and venous (R _v). The capillary filtration coefficient (K _f,c) was evaluated by measuring the weight gained by the lungs when the arterial and venous pressures were suddenly increased. In the youngest Landrace piglets (5 weeks old), there was an uncontrolled vasoconstriction which sometimes prevented perfusion of the lungs and induced a large increase inR _t. These high values ofR _t were decreased by tolazoline administration. The values ofR _t recorded in older pigs (12–13 weeks old) were lower in Minipigs (33.66±3.77 cmH₂O min L^–1 per 100 g of lungs;n=5) than in Landrace piglets (55.20±6.18 cmH₂O min L^–1 per 100 g;n=5). This breed difference was due to the differences inR _a andR _v. The mean values ofK _f,c were 0.193±0.015 and 0.202±0.029 ml min (cmH₂O)^–1 per 100 g of the lungs in Minipigs and Landrace piglets respectively. All these parameters were stable for the 3 hours following the equilibrium period. It was concluded that: (1) There is an age-related maturation of the control of the vasomotor tone in porcine lungs. (2) Pulmonary microvascular haemodynamics are influenced by the breed of the pigs. (3) There was no difference in theK _f,c values between both the breeds. (4) A comparison of the values reported for dogs and rabbits with our data shows that the pre- and post-capillary resistances and, to a lesser extent, the arterial and venous resistances are relatively high in pigs.     

椰糠对黄瓜穴盘苗生长发育的影响

将草炭、椰糠、蛭石按不同比例配制育苗基质,探讨椰糠对黄瓜秧苗生长发育的影响。结果表明,椰糠具有较好的保水性,酸碱度适合于作为穴盘育苗基质,出苗情况较好,秧苗质量高,证明椰糠是一种良好的园艺栽培基质。     

高能日粮条件下半胱胺对大鼠抗氧化功能的影响

通过在正常日粮中添加高油脂来制备高能日粮,探讨高能日粮条件下,添加0、15、30、60mg/kg半胱胺(CS)对大鼠抗氧化功能的影响。试验结果表明:添加15、30mg/kg半胱胺均能显著提高大鼠抗氧化能力(P<0.05),30mg/kg半胱胺能使大鼠抗氧化能力恢复到接近正常日粮组水平,60mg/kg半胱胺对大鼠抗氧化能力的恢复无显著影响(P>0.05)。半胱胺添加的最适剂量为30mg/kg。     

Gene Flow Analysis of Phytophthora porri Reveals a New Species: Phytophthora brassicae Sp. Nov.

Isozyme analysis and sequence analysis of the internal transcribed spacer regions (ITS-1 and ITS-2) and the 5.8S subunit of the ribosomal DNA gene repeat were used to examine whether isolates of Phytophthora porri from Allium and Brassica represent a single homogeneous species. Twenty-six strains of P. porri, 16 strains isolated from the genus Allium, and 10 strains isolated from the genus Brassica, were analyzed using malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH) and lactate dehydrogenase (LDH), represented altogether by four putative loci (Mdh-2, Idh-1, Idh-2, and Ldh-2). Isozyme analysis revealed that strains isolated from Allium contained five private alleles at three isozyme loci (Ldh-2 ⁸³, Ldh-2 ¹⁰⁴, Idh-1 ¹⁰⁸, Idh-1 ¹¹², and Idh-2 ⁹⁸), whereas six different alleles were observed at four isozyme loci (Ldh-2 ⁸⁵, Ldh-2 ¹⁰⁰, Ldh-2 ¹¹⁴, Idh-1 ¹⁰⁰, Idh-2 ¹⁰⁰, and Mdh-2 ¹¹¹) in strains obtained from Brassica. The heterozygosity at the Ldh-2 locus, differing in allele composition, however, between strains from Allium and Brassica, was present in all strains, indicating that it is probably fixed. Sequence analysis of the ITS regions and the 5.8S subunit showed consistent differences between isolates from Allium and isolates from Brassica. Based on isozyme data, ITS sequence analysis and formerly published differences in restriction enzyme patterns of mitochondrial DNA, morphology and pathogenicity, it was concluded that the isolates of P. porri Foister did not represent a homogeneous species. Isolates from Brassica constitute a distinct species which is described here as P. brassicae sp. nov. It was inferred from isozyme patterns, which were in no case intermediate between the two species, that P. porri and P. brassicae do not hybridize and are reproductively isolated by barriers to gene flow.     

孔雀河流域绿洲生态支持系统调控模式研究

生态环境用水量的减少是孔雀河流域近 50年来现代绿洲环境退化的主要原因 ,维持生态与社会经济的合理用水比例是绿洲系统持续发展的前提。以此为基础 ,本文采用水资源承载力的方法探讨了绿洲生态支持子系统和社会经济子系统优化调控模式 ,最后就配置方案及发展模式的可行性进行了分析     

杏鲍菇优良品种HRX的选育研究

通过对杏鲍菇优质菌株HRX3定向驯化试验,结果表明:经过热处理的菌株,其对温度的耐受性能有明显改善;提高培养基中的木质素和纤维素成分,可以增强菇体内相关酶的活性;并筛选出适合本地栽培该菇的培养基质.     

利用废菌糠提高覆土持水力和蘑菇产量的研究

本文利用平菇等食用菌的废菌糠 ,经适当无氧发酵等一系列处理后添加到普通泥土中 ,使其最大持水力提高至 5 1 3% ,单产提高 13 6 %     

Using traffic flow theory to model traffic mortality in mammals

Traffic has a considerable effect on population and community dynamics through the disruption and fragmentation of habitat and traffic mortality. This paper deals with a systematic way to acquire knowledge about the probabilities of successful road crossing by mammals and what characteristics affect this traversability. We derive a model from traffic flow theory to estimate traffic mortality in mammals related to relevant road, traffic and species characteristics. The probability of successful road crossing is determined by the pavement width of the road, traffic volume, traversing speed of the mammals and their body length. We include the traversability model in a simple two-patch population model to explore the effects of these road, traffic and species characteristics on population dynamics. Analysis of the models show that, for our parameter ranges, traffic volume and traversing speed have the largest effect on traffic mortality. The population size is especially negatively affected when roads have to be crossed during the daily movements. These predictions could be useful to determine the expected effectiveness of mitigating measures relative to the current situation. Mitigating measures might alter the road and traffic characteristics. The effects of these changes on traffic mortality and population dynamics could be analysed by calculating the number of traffic victims before and after the mitigating measures. This revised version was published online in July 2006 with corrections to the Cover Date.     

西北内陆河流域水资源利用的生态经济研究

水资源是西北内陆河流域生态环境建设和经济社会发展的控制因素,是进行各类基础设施建设的前提条件.利用生态经济学中的生态经济协调发展理论和可持续发展的思想,从生态、社会和经济3个方面对水资源开发利用的可持续性进行综合评价,找到水资源生态系统和社会经济系统的平衡点,达到生态和经济平衡,实现水资源的可持续利用.