河西走廊北部荒漠草地长爪沙鼠防治指标研究

长爪沙鼠是河西走廊北部荒漠草地的优势鼠类,危害严重。古浪县位于河西走廊东部,北部荒漠草地的长爪沙鼠,5月鼠密度在29．1只／hm^2～52．3只／hm^2之间,至9月造成牧草损失586kg／hm^2。通过调查鼠密度和牧草损失量,结果充分显示长爪沙鼠的种群密度与其造成的损失量之间呈明显的正相关关系,其回归方程式为：M=13．96×-8．10。通过防治及综合分析研究后提出在河西走廊的古浪县北部荒漠草地长爪沙鼠的防治指标为5．33只／hm^2,5月份防治。     

Metabolism of flupyrazofos in the isolated perfused rat liver

To investigate the hepatic metabolism of the new insecticide flupyrazofos [O,O-diethyl O-(1-phenyl-3-trifluoromethylpyrazol-5-yl) phosphorothioate], isolated rat liver was perfused with flupyrazofos under single-pass conditions. In outflow perfusate and bile, 1-phenyl-3-trifluoromethyl-5-hydroxyprazole (PTMHP), PTMHP-sulfate and PTMHP-glucuronide conjugates were identified as the metabolites of flupyrazofos. However, O,O-diethyl O-(1-phenyl-3-trifluoromethylpyrazol-5-yl) phosphate (flupyrazofos oxon) was not detected. A HPLC method with UV detection was used to investigate the hepatic disposition of flupyrazofos and its metabolite PTMHP. The concentrations of flupyrazofos, PTMHP and PTMHP conjugates in outflow perfusate reached steady-state levels within 20 min after commencing perfusion of 7.3 microM flupyrazofos. At steady state, the mean extraction ratio of flupyrazofos was 0.93 (+/- 0.01) and clearance was 26.1 (+/- 0.2) ml min-1 which nearly approached perfusate flow rate (28 ml min-1). PTMHP accounted for 55.7 (+/- 5.8)% of eliminated flupyrazofos and was recovered as unchanged PTMHP, PTMHP-sulfate and PTMHP-glucuronide in the bile as well as the outflow perfusate.     

Effects of Soybean Fortification on Protein Quality of Tortilla-Based Diets Produced from Regular and Quality Protein Maize

The physiological development of laboratory rats fed with a typical indigenous tortilla diet was studied for two generations. The experiment compared casein control diet and five different types of diets: (1) a diet of tortillas obtained from fresh masa (FM); (2) regular tortillas produced from enriched dry masa flour containing vitamins B₁, B₂, niacin, folic acid, and the microminerals iron and zinc (REDMF); (3) tortillas produced from enriched dry masa flour fortified with 6% defatted soybean meal (FEDMF); (4) tortillas produced from enriched quality protein maize flour (EQPM); and (5) and, tortillas produced from enriched quality protein maize flour fortified with 3% defatted soybean meal (FEQPM). The growth of rats fed FEDMF and FEQPM diets was significantly higher (P<0.05) in both generations than their counterparts fed EQPM, REDMF, or FM diet. Animals fed quality protein maize (QPM) tortilla had the highest protein digestibility, but the FEQPM and FEDMF diets had the highest biological value (BV), net protein utilization (NPU), and protein-digestibility-corrected EAA scores (PDCEAAS). The difference among treatments was more evident in the second-generation rats. The pregnancy rate, number of newborns/litter, litter weight, and newborn survival rate was also higher for rats fed FEDMF, EQPM, and FEQPM diets than their counterparts fed REDMF and FM.     

Keystone effects of the endangered Stephens' kangaroo rat (Dipodomys stephensi)

Kangaroo rats (Dipodomys) have been argued to exert keystone effects because they interact strongly with other species, and their removal results in major changes in community structure. We evaluated the nature and magnitude of such impacts by the endangered Stephens' kangaroo rat (Dipodomys stephensi), employing an exclosure experiment to determine how the removal of this species impacted relative cover by vegetation, plant species diversity, abundance of a dominant annual plant genus (Erodium), and predation of seeds from artificial trays. Fifteen months of D. stephensi removal resulted in significant increases in herb cover and Erodium abundance, and significant declines in bare ground and in seed predation. These results support the hypothesis that D. stephensi has major impacts on plant community structure and seems to function as a keystone species. It remains to be seen how the loss of this species from much of its range will influence local community composition and dynamics.     

Lipopolysaccharide induces expression of collagen VI in the rat lung

The involvement of the lung during the septic systemic inflammatory response elicited by administration of lipopolysaccharide (LPS) was investigated. Eight-week-old male Sprague–Dawley rats were injected i.p. with 15 mg/kg LPS. After 24 h, the lungs were excised to evaluate the cellular responses to LPS. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) analysis revealed that type VI collagen (ColVI) was extremely upregulated during sepsis in the rat lung within the first 24 h of LPS administration. Upregulation of ColVI protein and its mRNA was demonstrated by Western blot analysis, real time PCR, and immunohistochemistry. To the best of our knowledge, this is the first report demonstrating the activation of ColVI in the rat lung at the early stage of systemic inflammation. Activation of ColVI might be involved in sepsis-mediated lung fibrosis at an early stage.     

酸枣仁散对运输应激大鼠脑内5-HT表达的影响

为研究运输应激对脑内五羟色胺(5-hydroxytryptamine,5-HT)表达的影响及酸枣仁散对运输应激的调控作用,试验采用摇床模拟公路运输途中的摇晃、高温和拥挤等因素,建立大鼠运输应激模型(35℃,60r/min,每天应激2h,连续7d)。将40只大鼠随机分为对照组、酸枣仁组、应激组和应激+酸枣仁组,分别处理7d后,断头取脑,利用酶联免疫吸附法(ELISA)和免疫组化法检测各组大鼠脑区5-HT含量变化及分布。酶联免疫吸附法检测结果显示,与对照组相比,应激组大鼠中缝核、海马和纹状体等脑区5-HT表达量均明显减少(P0.05),应激+酸枣仁组较应激组5-HT表达量显著增加(P0.05)。免疫组化结果显示,在中缝背核及其亚核DRDsh、DRv和DRc亚核,应激组大鼠5-HT灰度值与对照组相比显著下降(P0.05),应激+酸枣仁组与应激组相比显著上升(P0.05)。以上结果表明,运输应激可以导致中枢神经系统部分脑区5-HT含量下降,而酸枣仁散可能通过上调脑内5-HT的含量来调控运输应激。     

MCT1抑制剂p-CMB对乙酰胆碱诱导的大鼠胰液分泌的影响

采用在体试验方法研究单羧酸转运蛋白第1亚型（monocarboxylate transporter 1,MCT1）抑制剂（p-chloromercuribenzene sulfonate,p-CMB）对乙酰胆碱（acetylcholine,Ach）诱导的大鼠胰液分泌的影响。Spra-gue-Dwley（SD）雄性大鼠,体重180g-210g,分6组,每组5只,试验前禁食24h,自由饮水。动物麻醉后经外科手术后,每隔10min收集一次胰液,采用Lowry法测定胰液蛋白量,Bernfeld法测定胰酶。结果对照组（-p-CMB）和实验组（＋p-CMB）,在注射1、5、10μg／kg的Ach后对胰液分泌量、胰蛋白分泌量以及胰淀粉酶分泌量都呈现增加作用,注射后1h内达到峰值,之后逐渐降低。然而,试验组的胰液分泌各项指标比对照组的显著减少（P〈0．01）。表明MCT1抑制剂p-CMB减弱了Ach增加大鼠胰液分泌的作用。     

中药复方制剂对大鼠和母猪骨质疏松症的防治效果试验

探讨中药复方对实验性大鼠骨质疏松症的预防和治疗作用,并在此基础上探索该中药对成年经产高龄母猪骨质疏松症的预防效果。对102只3月龄SPF级SD雌性大鼠用维甲酸造模并进行中药防治试验,造模结束和药物治疗结束后对大鼠进行骨密度检测、骨组织形态检测与血液生化指标(Ca、P、BALP和TRACP-5b)检测。同时,将35头6胎~8胎经产高龄母猪,4岁~5.5岁体重220kg^300kg长大二元杂母猪随机分为空白组、中药复方高、中、低(B1、B2、B3)3个剂量组,连续给药20d,检测母猪血液生化指标(Ca、P、TRACP-5b、CTX-Ⅰ、BALP和PINP)。结果表明,与模型组相比,中药组大鼠血清水平有显著降低,骨密度增加,骨微观结构得到改善;与空白组相比,中药中剂量组和高剂量组母猪血清BALP及PINP水平显著升高,TRACP-5b及CTX-Ⅰ水平显著降低。结果表明该中药复方制剂对大鼠和猪骨质疏松症的治疗有良好效果。     

Methicillin‐resistant Staphylococcus aureus in urban Norway rat (Rattus norvegicus) populations: Epidemiology and the impacts of kill‐trapping

Urban Norway rat (Rattus norvegicus) populations can carry the bacteria methicillin‐resistant Staphylococcus aureus (MRSA). There are numerous knowledge gaps in the epidemiology of MRSA in these populations that limit understanding of its ecology in urban environments. For example, fecal shedding of MRSA, which may increase environmental contamination, has been reported in other species; however, it is unknown whether Norway rats carry the bacteria rectally. Furthermore, while intermittent MRSA shedding has been shown in other species and may dictate when the risk of transmission is highest, duration of carriage has not been examined for Norway rats. Previous work has shown that lethal animal‐control methods may increase the level of pathogens within reservoir populations, possibly by disrupting ecological patterns. However, the impact of rodent‐control on potentially environmentally acquired pathogens like MRSA has not been tested. Using capture‐mark‐recapture methods in an inner‐city neighborhood in Vancouver, Canada, we show that rats intermittently carry MRSA both in the rectum and oropharynx. By assessing the prevalence of MRSA before and after enacting a pest‐control intervention, we report that kill‐trapping had no impact on the prevalence of carriage of this environmentally‐acquired agent.