抗柑桔褐斑病菌和炭疽病菌宽皮柑桔种质的筛选

由交链格孢菌Alternaria alternata和胶孢炭疽菌Colletotrichum gloeosporioides侵染引起的柑桔褐斑病和炭疽病是重庆万州地区红桔的主要真菌病害。为筛选适合万州地区发展的柑桔品种,采用离体叶片室内人工接种和病情指数抗性评价方法探讨了16份宽皮柑桔种质对柑桔褐斑病菌和炭疽病菌的抗性。结果表明：对于柑桔褐斑病菌,不知火桔橙、W?默科特、春见桔橙和温州蜜柑为高抗种质;对于柑桔炭疽病菌,不知火桔橙、W?默科特、蔓生红桔和苏红为高抗种质。综合考虑,重庆万州地区可选择抗病性较强的鹅蛋红桔、福桔、安江红桔、不知火桔橙和W?默科特等宽皮柑桔进行品种替换和提升。     

40个苜蓿品种对炭疽病的苗期抗性评价

三叶草炭疽菌(Colletotrichum trifolii)是引起苜蓿炭疽病的重要致病菌,发生严重时可导致苜蓿毁灭性危害。采用孢子悬浮液喷雾接种法,以发病率和病情指数为指标,对40个苜蓿品种开展抗三叶草炭疽菌的苗期抗性评价。结果表明,供试品种中,威纳尔、阿尔冈金、巨能2表现高抗,WL363HQ、巨能7、拉迪诺、4030、4010、润布勒、亮牧表现中抗,新牧4号、甘农4号、驯鹿等15个品种表现中感,新疆大叶、甘农6号、甘农9号等15个品种表现高感。抗性品种占供试品种的25%,感病品种占75%,高抗与高感品种间抗性差异显著(P < 0.05)。     

40个苜蓿品种对炭疽病的苗期抗性评价

三叶草炭疽菌(Colletotrichum trifolii)是引起苜蓿炭疽病的重要致病菌,发生严重时可导致苜蓿毁灭性危害.采用孢子悬浮液喷雾接种法,以发病率和病情指数为指标,对40个苜蓿品种开展抗三叶草炭疽菌的苗期抗性评价.结果表明,供试品种中,威纳尔、阿尔冈金、巨能2表现高抗,WL363HQ、巨能7、拉迪诺、4030、4010、润布勒、亮牧表现中抗,新牧4号、甘农4号、驯鹿等15个品种表现中感,新疆大叶、甘农6号、甘农9号等15个品种表现高感.抗性品种占供试品种的25％,感病品种占75％,高抗与高感品种间抗性差异显著(P<0.05).     

邵阳柑橘炭疽病菌的分离鉴定和药剂筛选初报

【目的】明确邵阳地区柑橘炭疽病病原菌的种类及其致病性,针对性开展防治药剂初筛试验研究,为邵阳柑橘炭疽病防控提供理论依据。【方法】对采自湖南邵阳的炭疽病样品采用病原菌的分离、形态学特征观察和分子生物学的方法进行鉴定,采用室内离体接种的方法对病原菌致病性进行测定,并通过病原菌侵染切片观察分析其侵染特性。此外,采用菌丝生长速率法测定7种不同药剂对病原菌的抑菌效果。【结果】分离到了11株具有相同形态特征的菌株。结合rDNA-ITS、rDNA-GAPDH和rDNA-ACT序列构建系统进化树分析病原菌为胶孢炭疽菌（Colletotrichum gloeosporioides）,且发现该菌表现出较强的致病性,多在叶片气孔处侵染为害。在7种供试药剂中,250g/L吡唑醚菌酯抑菌效果最明显,EC50为0.756mg/L。【结论】邵阳主要柑橘产区炭疽病致病菌为胶孢炭疽菌,多在叶片气孔处潜伏侵染为害。250g/L吡唑醚菌酯对柑橘炭疽菌具有良好的室内抑菌效果,有柑橘炭疽病防治的应用潜力。     

柑橘炭疽病研究进展

柑橘炭疽病是常见的柑橘病害,虽然该病被研究多年,取得显著成果,但对该病的探究仍需深入。本文以胶孢炭疽菌和尖孢炭疽菌为主要论述对象,综述了近年来国内外对这两种病原菌的研究状况,包括炭疽菌的种类及侵染循环、鉴定、致病机理和防治方法等。此外,本文还提出了未来该病研究需要解决的问题及发展方向。     

芒果果皮蜡质结构对果实抗炭疽病的影响

芒果炭疽病是芒果的重要病害,为了探明芒果果皮蜡质结构在其抗炭疽病过程中发挥的作用,本研究采用胶孢炭疽菌孢子悬浮液无伤接种的方法对20个芒果品种脱蜡处理前后的抗病情况进行分析,并利用扫描电子显微镜观察其表皮蜡质结构变化,结果表明：蓝丁胶粘黏脱蜡可破坏芒果表皮蜡质结构,使其片层状蜡层减少,蜡质裂痕增多。脱蜡处理后,部分芒果发病率升高,热农1号、椰香和红象牙等10个芒果品种果实脱蜡处理后其对炭疽病抗性显著下降。说明脱蜡可导致果实发病速度加快、抗病性降低,证实蜡质结构在部分芒果品种果实抗炭疽病菌侵染过程中发挥了重要的物理屏障作用。     

33种芒果对细菌性角斑病的抗性评价

【目的】由柑橘黄单胞菌芒果致病变种引起的细菌性角斑病是一种危害严重的细菌性病害,筛选和培育抗病品种是目前最经济有效的防控手段。鉴定评价芒果种质对细菌性角斑病菌的抗性,可为芒果抗病新品种选育提供理论依据。【方法】选取我国芒果种质凯特、热农一号、澳芒和金煌等33个常用栽培品种,采用室内离体芒果果实刺伤接种的方法,根据不同芒果种质的感病情况,结合系统聚类分析法、病斑平均直径法、病情指数法等评价方法对其抗病性进行分级。【结果】在33份芒果种质中,热农一号和KRS对细菌性角斑病表现为高抗, Zillate、鹰嘴等5个品种为中抗材料;中感材料有0902、0905、圣心、玉文等15个;感病材料有广西四号、东镇红芒、大头芒7个;高感材料凯特和红象牙等4个。【结论】2个高抗品种和4个高感品种可用于芒果抗病育种的进一步研究。     

2种麦冬炭疽病菌生物学特性的研究

胶孢炭疽菌和黑线炭疽菌是麦冬炭疽病的病原菌.胶孢炭疽菌菌丝体生长、产孢和孢子萌发的最适温度都为28℃,黑线炭疽菌的分别为25,28和25℃.弱酸条件有利于2种炭疽菌菌丝体的生长和产孢,在pH值为4时产孢量都达到最大值,胶孢炭疽菌在pH值为7时孢子萌发率最大,黑线炭疽菌在pH值为8时达最大.光照处理对这2种病菌营养生长和产孢均无显著影响.供试碳源中果糖和葡萄糖有利于胶孢炭疽菌的菌丝体牛长,山梨糖和淀粉有利于其产孢;麦芽糖有利于黑线炭疽菌的菌丝体生长,淀粉有利于其产孢;氮源中有机氮有利于2种炭疽菌生长和产孢,化学氮源则表现抑制作用.胶孢炭疽菌和黑线炭疽菌的致死温度分别为55和50℃10 min.     

不同黑麦草品种抗病性评价

通过对20个黑麦草品种自然发病调查,采用病级分类和系统聚类分析方法进行抗病性评价。结果表明,对锈病表现抗性和中抗的品种有10个和5个,分别占供试品种的50%和25%;对镰孢枯萎病表现抗性和中抗的品种有14个和4个,分别占供试品种的70%和20%;对灰梨孢灰斑病表现抗性和中抗的品种有14个和5个,分别占供试品种的70%和25%;对离孺孢叶斑病表现抗性和中抗的品种有14个和6个,分别占供试品种的70%和30%。多数品种对黑麦草4种病害抗性表现较好,可从黑麦草供试材料中选用优良抗病材料用于四川地区种植;也可从黑麦草供试材料中选择感病或高抗型品种进一步研究黑麦草抗病性机理。     

13种杀菌剂对芒果炭疽病菌的室内毒力测定及田间防效

近年来芒果炭疽病在贵州芒果园发生普遍、危害极重,通过本研究掌握芒果胶孢炭疽菌（Colletotrichum gloeosporioides Penz）对不同杀菌剂的毒力及田间防治效果,将为芒果炭疽病的防治提供理论依据。采用生长速率法测定13种杀菌剂对芒果胶孢炭疽菌的毒力,结果表明：13种杀菌剂中450g/L咪鲜胺EW对胶孢炭疽菌抑菌效果最好,EC50小于0.01mg/l,250克/升吡唑醚菌酯EC、50%氟啶胺SC、50%多菌灵WP和12.5%氟环唑SC的EC50均小于1 mg/L,对胶孢炭疽菌具有较好抑菌效果。芒果幼果期进行田间防治,结果表明：450g/L咪鲜胺EW1500倍液、250克/升吡唑醚菌酯EC1250倍液、50%多菌灵WP1000倍液、12.5%氟环唑SC2000倍液、250g/L嘧菌酯SC1250倍液、50%氟啶胺SC1500倍液和70%甲基硫菌灵WP1000倍液等7种药剂可相对有效地控制芒果炭疽病的发生,防效为57.57%~65.57%。该研究将为贵州芒果炭疽病的防治提供理论依据及技术支撑。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Evaluation of the Microbiological Status of Milk and Various Structures in Mammary Glands from Naturally Infected Dairy Cows

A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.