Estimation of the viability ofHeterodera schachtii field populations by measuring ATP,ADP and AMP contents of eggs and juveniles using HPLC

An HPLC method has been developed to determine adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in eggs and juveniles ofHeterodera schachtii in cysts extracted from soils. ATP levels in eggs and juveniles were highly correlated with the numbers of hatched juveniles in root diffusate (r=+0.92) in series of soil samples originating from field trials testing different doses of fumigant nematicides. The measured ATP concentrations in the cysts explained 59% of the sugar-yield reduction on these fields, which was similar to the value based on the hatching test. After fumigation, carried out in a laboratory experiment, ATP and the adenylate energy charge, (AEC=ATP + 0.5 * ADP)/(ATP + ADP + AMP), decreased greatly within a few days. In a series of greenhouse trials in whichH. schachtii had been parasitized severely byVerticillium clamydosporium and other antagonists, there were significant correlations between the numbers of hatched juveniles and the ATP content of the cysts (r=+0.85), and between the percentages of hatched juveniles and the AEC (r=+0.75). The HPLC method is faster than conventional methods and can be used to establish the viability ofH. schachtii field populations affected by soil fumigation or egg pathogens.     

Vapor pressure and volatility of β-asarone,the main ingredient of an indigenous stored-product insecticide,Acorus calamus oil

The effect ofAcorus calamus products on insects is reviewed briefly. A sudden, dramatic drop occurs in the insecticidal, gaseous phase activity of calamus oil on stored-product pests, when the exposure temperature is lowered from 30° to 25°C. In an attempt to explain this finding, the vapor pressure of the main constituent of IndianAcorus calamus essential oil, β-asarone, was determined by three methods: (i) extrapolation with a gas-chromatographic method according to Jensen and Schall; (ii) calculation from boiling points with the Clausius-Clapeyron equation; and (iii) direct measurement with the Knudsen cell. The values of vapor pressure of β-asarone at 30°C according to these three methods were 3.3 x 10^-3, 3.7 x 10^-3 and 9.8 x 10^-4 Torr, respectively. The volatility of β-asarone under the conditions of the fumigant experiments mentioned above was assayed by determining the weight loss from 50 mg asarone allowed to evaporate at 30°C from a filter paper disk into a 400 ml hermetically closed glass vessel. The weight loss was approximately 0.75 mg/400 ml receptacle space (≈1.9 mg/l) for every 10 days from day 0 to day 40.     

Development of ZWIPERO, A Model Forecasting Sporulation and Infection Periods of Onion Downy Mildew based on Meteorological Data

The weather-based forecasting model ZWIPERO was developed by the German Weather Service and determines the risk of sporulation and infection of Peronospora destructor quantitatively based on actual as well as predicted weather data (temperature, relative humidity, leaf wetness, precipitation). The model allows precise planning of disease monitoring and infection-related application of fungicides. ZWIPERO is a more complex mathematical model than the previously published models for downy mildew. In order to operate ZWIPERO independently of the actual field location and season, the time of sunrise and sunset of the location are exactly determined by a subroutine. Another subroutine provides simulated microclimatic input variables based on local production data as well as actual and hourly predicted (up to 4 days) standard weather data. Starting at the time of 'sunrise + 7 h', ZWIPERO calculates the number of sporangia produced, the time of onset of sporangia release, as well as the number of infections possible and the number of sporangia which may survive the day for each 24-h time step. Field evaluations of sporulation periods of downy mildew showed that the simulated micrometeorological input variables are reliable. As the actual plant development, the susceptibility and the disease incidence in the field are not taken into account, ZWIPERO has to be considered primarily as a decision support system for extension services and growers.     

SPF鸡屏障系统净化技术研究

本文从理论上较为系统地对SPF鸡实验动物房的净化管理技术进行研究,对净化原理,洁净度、压力梯度以及该动物房各个部位、洁净室的风量风速、压力损失和静压差进行了分析和计算,使读者对SPF鸡屏障系统有了较清晰的认识。希望对相关净化管理人员有一定的参考价值。     

Effects of Carbon Dioxide Insufflation and Body Position on Blood Gas Values in Horses Anesthetized for Laparoscopy

The objective of the study was to describe the effects of carbon dioxide pneumoperitoneum and Trendelenburg position on arterial blood gas values in horses anesthetized for laparoscopy. The study design was a prospective case series using 14 healthy adult horses anesthetized for elective laparoscopic surgery. All horses in the study were maintained under anesthesia with halothane in oxygen with intermittent positive-pressure ventilation. A pneumoperitoneum of 15 mmHg or less was achieved with carbon dioxide, and horses were tilted to a 35-degree Trendelenburg position to allow the completion of laparoscopic cryptorchidectomy (n = 13) or ovariectomy (n = 1). Heart rate, mean arterial pressure, and arterial blood gases were recorded at six time intervals throughout the procedure. Results of the study indicated a pH that decreased and partial pressure of carbon dioxide (PaCO₂) and mean arterial pressure that increased over time and differed significantly from baseline during Trendelenburg position. Partial pressure of oxygen (PaO₂) was significantly lower than baseline after assumption of Trendelenburg position and did not improve on return to normal recumbency and abdominal pressure. As body weight increased, pH and PaO₂ decreased and PaCO₂ increased. We concluded that horses placed in Trendelenburg position have changes that are transient, with the exception of PaO₂. Heavier horses have a greater change in pH, PaCO₂, and PaO₂ than lighter horses during abdominal insufflation and Trendelenburg position. The changes incurred during CO₂ abdominal insufflation and Trendelenburg position are transient, with the exception of a decreased PaO₂. Heavy horses undergoing abdominal insufflation and Trendelenburg position should be closely monitored for critical cardiopulmonary values.     

Estimation of left ventricular filling pressure by Doppler echocardiography in dogs with pacing-induced heart failure

BACKGROUND: Congestive heart failure (CHF) is a common clinical syndrome characterized by elevated filling pressure. HYPOTHESIS: Doppler echocardiographic (DE) variables of left ventricular (LV) filling can predict a decline of LV end-diastolic pressure (LVEDP) induced by acute preload reduction in dogs with compensated CHF. ANIMALS: Five male hound dogs. METHODS: Dogs previously instrumented with a transvenous cardiac pacemaker and a LV pressure gauge were paced at 160-180 bpm to induce mild CHF characterized by LVEDP > 20 mmHg. LVEDP and 9 DE variables of LV filling derived from diastolic time intervals, transmitral and pulmonary venous flow, and tissue Doppler imaging were measured simultaneously at baseline and 30, 60, 120, and 240 minutes after furosemide (4 mg/kg, IV) or placebo (0.9% saline, IV). Repeated measures analysis of variance and correlation analysis were used to determine the association between the decline of LVEDP after furosemide and DE measures of LV filling pressure (LVFP). RESULTS: Furosemide but not placebo decreased LVEDP (P < .001). The ratio of early transmitral flow velocity to LV isovolumic relaxation time (E : IVRT) predicted LVEDP best (R(2)= .50; P < .001). Correlations were also found between LVEDP and IVRT, E, ratio between E and late diastolic transmitral flow velocity (E : A), and early diastolic velocity of the mitral annulus (Ea). The ratio of E to Ea (E : Ea) was not useful in the prediction of LVEDP in this model. CONCLUSION AND CLINICAL IMPORTANCE: E : IVRT can be used to predict LVFP in dogs with mild left-sided CHF induced by rapid pacing.     

Use of continuous positive airway pressure in the acute management of laryngeal paralysis in a cat

Continuous positive airway pressure (CPAP) has been is used widely in humans to manage obstructive sleep apnoea syndrome, but it has not been widely used in animals. A brachycephalic cat, with previously undiagnosed laryngeal paralysis, that developed acute upper respiratory tract obstruction on recovery from anaesthesia, is presented. The condition was managed by CPAP, delivered via a facial mask.     

低排泄氮量的鹌鹑改良选育

选用日本鹌鹑N、B（Normal、Brown）品系和杂种群（BN）,共进行8个世代（6～20周龄）的选育试验,各品系采用单因子试验设计,在CP18％日粮条件下分选育组、非选育组以及对照组（CP24％）,N、B基础群中选留15种家系,以采食量为主选性状,以产蛋率和排泄氮量为辅选性状作为选育指标进行试验。结果表明：随着世代数的增加选育组和对照组的适应力均有显著升高（P〈0．05）,N品系的各世代遗传改进量为0．26;另外,世代间产蛋率有增高的倾向,选育组平均累积产蛋率与非选育组较显著升高（P〈0．05）,特别是选育组各世代遗传改良极为显著（P-〈0．01）。各世代间采食量无显著差异,同世代各品系间选育组N、B采食量均高于非选育组,但显著低于对照组（P〈0．05）。选育组排泄氮量和血清中尿酸含量在改良2世代后明显低于非选育组和对照组（P〈O．05）,排泄氮量分别降低7％～15％。综上所述,通过选育N、B新品系,能够改善产蛋性能,且显著降低排泄氮量,在BN杂种群中效果更明显。     

吉富品系尼罗罗非鱼选育过程中遗传变异的微卫星分析

采用微卫星标记技术对选育新品种新吉富罗非鱼（F8－9）群体、基础群体（F0）、以及选育中群体（F6－7）在选育过程中出现的遗传变异进行观察与分析。19个微卫星位点扩增后的等位基因数为3～11个，随引物不同而异，合计得到115个等位基因，大小在70～270 bp之间。五群体平均基因多样性指数分别为，F0：(0.3083±0.1834)、F6：(0.2982±0.1889)、F7：(0.2923±0.1898)、F8：(0.2572±0.1923)、F9：(0.2743±0.1597)，表明随着选育的进展，群体呈现出纯化趋势。AMOVA分析表明，在总遗传变异中，93.24%来自选育群体内，仅6.67%来自选育群体间。群体间的校正偏差后相似性系数在 F0与F6、F7之间分别为0.943 5和0.942 2，相对较高；而在F0与F8、F9之间分别为0.933 2和0.930 3, 相对较低。遗传距离在F0与F6、F7之间分别为0.058 1和0.059 5，相对较小；而在F0与F8、F9之间分别为0.069 1和0.072 2,相对较大。配对比较Fst值在F0与F6、F7之间分别为0.037 68和0.064 37，平均 值为0.051 03；而在F0与F8、F9之间分别为0.060 93和0.075 87，平均值为0.068 40，有所提高。这些指标的分析结果表明，经9年9代选育，已在罗非鱼世代间造成程度虽小但却可监测到的遗传分化；同选育群体F6－7相比，\"新吉富罗非鱼\"（F8－9）在遗传上更为稳定。图1表4     

浅议给水管道材质的使用

介绍了新型给水管道材质的优良特性以及在材料检验、施工和选用方面的注意事项。