乙烯利对干旱胁迫下草地早熟禾抗氧化酶基因表达的影响

为探究喷施乙烯利提高植物抗氧化酶活性进而提高植物抗旱性在基因层面的调控、作用机制,以草地早熟禾（Poa pratensis）为试验材料,以前期获得的草地早熟禾高通量转录组测序数据为研究对象,分析并筛选出抗氧化酶编码基因,研究不同处理下抗氧化酶编码基因表达量的差异情况,从基因水平探讨乙烯利对干旱胁迫下抗氧化酶编码基因响应乙烯利调控的表达模式。结果表明,干旱胁迫下各亚细胞区室响应乙烯利处理的抗氧化酶编码基因数量和表达情况均不同;喷施乙烯利处理,显著改变了干旱胁迫下11个基因的表达量,Chl Cu-Zn SOD2,Chl SOD copper chaperone1,Chl MR3,Cyt APX2,Nuc MR的表达量显著提高,Chl GPX2,Cyt CAT3,Cyt GPX1,Per CAT isozyme,Cu-Zn SOD1,MR2表达量显著降低;干旱胁迫下,响应乙烯利调控基因数目最多的亚细胞区室依次为叶绿体、细胞质。本结果为研究乙烯利提高植物抗旱性机制提供理论依据。     

乙烯利可引起母猪流产

乙烯利又名乙烯磷，分子式C2H6ClO3P，化学名称2-氯乙基膦酸，是一种高效的植物生长调节剂。因其能在植物的根、荚、花和果实等组织中释放出乙烯，调节植物的代谢生长和发育，加速成熟、脱落、衰老等，故常作为催熟剂应用于瓜果、蔬菜生产。关于乙烯利对动物的影响，报道甚少。笔者所在农场一养猪户因给妊娠母猪食用喷洒过乙烯利的苋菜，结果导致22头母猪流产，造成不应有的损失。现将有关情况报告如下，供养殖户参考借鉴。     

乙烯利浸种对不同土壤水分条件下多年生黑麦草幼苗生长的影响

本试验以多年生黑麦草‘爱神特’(Lolium perenne cv.Accent)种子为材料,土壤设3个水分梯度,分别为田间最大持水量的30%(FWC 30)、50%(FWC 50)、70%(FWC 70),模拟重度干旱、水分适宜、水分充足的土壤水分条件。同时设4个浸种处理分别为0(CK)、0.05%、0.1%、0.2%浓度的乙烯利溶液浸种24 h,通过测定出苗率、苗长、根系总表面积、根系总长度和侧根数等指标,探讨各乙烯利浸种处理对多年生黑麦草苗期抗旱性的影响。结果表明,适宜多年生黑麦草生长的土壤含水量在田间最大持水量的30%~50%之间,过多的灌溉水并不利于多年生黑麦草的生长。0.05%~0.1%浓度乙烯利浸种能够在一定程度上减轻土壤水分因素的差异对多年生黑麦草生长造成的影响,但相比乙烯利浸种处理,土壤含水量对多年生黑麦草苗期生长的影响更大。     

水分胁迫下植物乙烯,脯氨酸积累气孔反应的研究现状

对植物在水分胁迫下乙烯，脯氨酸积累，气孔反应的研究现状以及这些指标在水胁迫下的生理特征进行了探讨，以期为植物的抗旱性品种选育，提高作物产量，发展干旱地区农业生产提供参考。     

乙烯利对干旱条件下多年生黑麦草生理指标的影响

本研究以'Neruda','Accent','MS','AST'4个品种多年生黑麦草(Lolium perenne L.)为试验材料,研究叶片喷施乙烯利对多年生黑麦草耐旱性的影响.结果表明,喷施乙烯利后干旱处理10 d时,'Neruda'、'MS'和'AST'叶片相对含水量显著提高,所有品种电解质渗透率均下降,'Ner...     

丛枝菌根真菌对植物抗旱性研究进展

植物作为固着生物,采取多种策略应对各种外界刺激和胁迫环境,其策略之一就是与丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)建立共生关系.AMF可与80％以上的陆地植物形成共生关系,促进植物生长发育,提高植物抗旱性.AMF增强植物的抗旱性机制主要包括促进土壤团粒结构形成、改善根系构型、提高植物吸收水分能力、增强植物营养摄取、提高植物光合能力及水分利用效率、降低植物氧化损伤、强化渗透调节能力、调节内源激素水平及诱导相关基因的表达.本文从形态、生理生化及基因表达等层面综述了近年来国内外有关AMF提高植物抗旱性方面的研究进展,并提出当前研究存在的问题及今后研究的建议,为加快AMF这一高效生物技术的应用提供帮助.     

两种催花剂处理对台农4号菠萝催花效果的影响

针对生产上台农4号菠萝诱导催花通常采用2-3次电石处理,其操作复杂,且不利于绿色安全生产,本研究采用植物天然生长调节剂乙烯利对台农4号菠萝进行诱导催花处理,比较两种催花剂不同浓度处理对台农4号菠萝抽蕾率、果实内外品质及产量的影响。结果表明,台农4号菠萝对乙烯利催花比较敏感,很低的浓度（16000倍稀释液）催花抽蕾率都可以达到99%以上,而高浓度（500和1000倍）40%的乙烯利和电石处理组的平均单果重无显著差异,均在在1.08kg以上,低浓度（2000和16000倍）40%的乙烯利处理则会导致果实重量下降。在果实外观上,高浓度乙烯利可以显著提高台农4号菠萝圆筒形果的比例,且采用500倍和1000倍40%的乙烯利催花处理后的圆筒果率显著高于其他处理,分别达98.81%、94.13%,较两次1.25%电石诱导催花处理组高32.17%。在果实内在品质方面,乙烯利催花处理组显著优于电石催花处理组,相关分析表明,乙烯利的催花浓度与果实维生素C含量、总糖含量、糖酸比和可溶性固形物呈极显著正相关,而与柠檬酸含量呈极显著负相关。综合果形、产量、果实内在品质,台农4号菠萝采用500倍40%乙烯利与0.2%尿素催花效果佳,处理组诱导催花抽蕾率99.69%、圆筒果率99.38%,平均单果重1.22kg、维生素C含量达40.45mg/100g、可溶性固形物17.93%、总糖17.84%、柠檬酸0.61%,糖酸比19.71,可替代电石催花。     

澳洲坚果主栽品种‘HAES294’和‘HAES800’乙烯利促落果高效采收方式研究

为降低澳洲坚果采收成本,提高采收效率,以澳洲坚果主栽品种‘HAES800’和‘HAES294’为材料,在果实成熟期喷施浓度为1.5 g/L、2.0 g/L和2.5 g/L的乙烯利溶液,对喷施乙烯利溶液后的落果情况、落叶情况和果实品质进行了研究,并对该方法的促落果效果和使用成本进行了评估。结果表明,品种‘HAES800’喷施上述浓度乙烯利溶液4周后的落果率分别达到94.10%、94.08%和93.67%,而同一时期CK的落果率仅有24.64%;品种‘HAES294’喷施上述浓度乙烯利溶液6周后的落果率则分别达到90.89%、93.17%和91.80%,而同一时期CK的落果率仅有53.27%;相比而言品种‘HAES800’对乙烯利溶液更敏感;建议在生产中品种‘HAES800’和‘HAES294’分别采用1.5 g/L和2.0 g/L的乙烯利溶液进行促落果采收;尽管喷施乙烯利会引起部分落叶,但不会对树体生长和果实品质产生影响。应用本方法可使澳洲坚果采收成本降低25.07%,具有巨大的推广应用前景。     

苜蓿乙烯应答因子基因的表达特性和生物信息学分析

乙烯应答因子(ethylene response factor,ERF)是植物特有的一类转录因子,参与植物生长发育和胁迫应答等多个生理生化过程。本研究以拟南芥AP2结构域为探针搜索美国国立生物技术信息中心(NCBI)的苜蓿属蛋白质数据库,运用生物信息学软件分析苜蓿乙烯应答因子的系统进化、疏水轮廓、二级结构、信号肽以及亚细胞定位情况。运用半定量RT-PCR技术研究5个紫花苜蓿乙烯应答因子基因(MsERF1, MsERF2,MsERF6, MsERF7, MsERF9)表达的组织差异性以及多种处理条件下的表达特性。结果表明,5个乙烯应答因子基因在叶中的表达量都明显高于其他组织,不同基因有不同的组织表达特性;NaCl和PEG6000对MsERF2的表达没有影响,但Al₂(SO₄)₃能诱导其表达,其余基因的表达都受这3种处理的诱导;脱落酸对MsERF2的表达没有影响,能够诱导其他基因的表达;生长素只能诱导MsERF6的表达,对其他基因的表达没有影响;赤霉素、茉莉酸甲酯和乙烯利对5个基因的表达都起促进作用。本研究为进一步研究苜蓿乙烯应答因子的结构和功能奠定了基础,同时为研究不同信号传导途径之间的相互作用提供了依据。     

果实成熟调控理论与实践

延缓或促进果实成熟,调节市场供给,是提高水果生产经营效益的现实需求。延缓果实成熟的方法主要有低温贮藏或1-甲基环丙烯处理,影响果实内源乙烯释放及果实软化过程,进而达到延长果实贮藏寿命的目的;而促进果实成熟的方法主要是采用乙烯利或乙烯气体等催熟。     

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.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

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.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

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