代谢组学在牧草与草坪草抗逆性中的研究进展

牧草和草坪草的生长和发育常常面临着严重的盐碱、干旱、高温等非生物胁迫的影响。代谢组学是功能基因组学和系统生物学研究的重要技术，它涉及不同物种的细胞调控过程中代谢物的识别和定量，能够在代谢水平上有效地筛选与植物产量和抗逆性等相关的重要代谢物。目前随着色谱和质谱等技术的发展，牧草和草坪草对胁迫响应的代谢组研究也取得了许多重大进步。本文总结了近5年来代谢组学在牧草与草坪草抗逆性研究中的进展，详细描述和讨论了在水分、温度、盐分等非生物胁迫下草类植物中重要响应代谢物的鉴定以及不同代谢通路的调节与变化过程，以期为牧草和草坪草抗逆性研究及认识其内在逆境适应机制提供理论基础。     

冷季型草坪草耐热性研究进展

冷季型草坪草耐寒性强，绿期长，观赏效果好，因此被广泛应用在气候过渡地带的公园、运动场及草坪中。但由于冷季型草坪草耐热性差，夏季高温会引起草坪草的一系列生理代谢过程紊乱，从而使其表观质量下降，病害频发，草坪休眠、枯黄甚至死亡，影响草坪观赏或运动功能的发挥。本研究从生理和分子机制两个方面，重点综述了冷季型草坪草在高温胁迫下碳代谢、抗氧化代谢、激素代谢、耐热基因和转录等方面研究进展，分析了目前冷季型草坪草耐热性研究存在的主要问题，并对其研究前景进行了展望，以期为进一步的冷季型草坪草耐热机理研究提供理论参考。     

结缕草生长抑制研究

多效唑和结缕草生长调控的应用扩大试验表明，它能有效减缓植株地上部生长，抑制率达到３７％，提高植株的根冠比，增强草坪草的抗逆性，降低土壤肥力损耗，降低草坪的杂草清除次数，减少草坪管理成本，效益显著。     

植物生长延缓剂在草坪上的应用

综述了植物生长延缓剂的分类以及对草坪草生长发育、抗逆性及草坪杂草的影响.总结得出,植物生长延缓剂可有效降低草坪草的植株高度,促进分蘖,增加绿度,提高草坪草的抗逆性,但对根系生长的影响和杂草的控制尚存在争议.     

温度胁迫对亚热带常用草坪草活性氧代谢相关酶的影响

研究了在高温和低温胁迫下,亚热带建坪常用草坪草叶片的活性氧代谢相关酶与细胞膜透性的变化,并依据"自由基"假说,探讨了温度胁迫条件下自由基对草坪草细胞(主要是细胞膜体系)的伤害机理,初步揭示了不同温度胁迫下草坪草受害的致成原因以及不同品种间的差异.研究结果表明,以活性氧代谢指标与细胞膜透性为评判抗性大小的依据,各类品种的抗寒性大小顺序是匍匐剪股颖Agrostis stolonifere>草地早熟禾Poa pratensis>多年生黑麦草Lolium perenne>高羊茅Festuca arundinacea>狗牙根Cynodon dactylon,抗热性大小顺序是狗牙根 > 高羊茅 > 草地早熟禾 > 多年生黑麦草 > 匍匐剪股颖.研究运用了亚热型草坪草活性氧代谢相关酶测定的方法进行了草坪草品种鉴定和抗性比较,为亚热带地区草坪草品种选择、建植和维护提供了科学的理论依据.     

高温胁迫下高羊茅生理生化特性研究

高温是制约冷地型草坪草生长发育最重要的生态因子之一。对草坪草高羊茅品种凌志Festucaarundinaceacv.Barlexas进行了高温胁迫下的生理生化研究。结果表明:在42/32℃(昼/夜)的高温胁迫下,植株的生长受到了明显的抑制,随着高温胁迫时间的延长,叶片的相对含水量明显下降;叶绿素含量呈先升高后下降的趋势;可溶性糖含量持续增加,其中胁迫至第5~7天增幅最大;脯氨酸和丙二醛(MDA)含量也逐渐增加,这些生理生化指标的变化可为寻求草坪草抗热种源提供科学的理论依据。     

草坪草耐荫性研究进展

荫蔽环境下，草坪草的微生境、植株形态特征、叶片解剖结构以及内源激素、光合等一系列生理代谢过程都发生了显著变化，以保证在弱光下仍能维持生长所需的能量平衡，进行正常的生命活动。通过对国内外草坪草的耐荫适应性评价及其生理响应机制等方面研究的阐述，指出了深入开展草坪草耐荫机制和大田条件下多种草坪草种间和品种间耐荫适应性评价研究的必要性。     

修剪高度对季节性温度变化下早熟禾生理生态特性的影响

修剪高度的差异会影响冷季型草坪草的生长,探究合理的修剪高度可为草坪草可持续利用提供理论基础。本研究通过测定两年生长季（2012年和2013年）草地早熟禾（8年生）草坪的外观质量（TQ）、地上部分生物量（AB）、光合作用（Pn）、总呼吸作用（R_total）和碳水化合物（TNC）等指标,探讨了修剪高度对冷季型草坪草生理生态特性的影响。试验结果表明,当大气温度高于23~24℃时,不同修剪高度7.6 cm （高修剪高度,HM）和3.8 cm （低修剪高度,LM）下的早熟禾TQ、AB和Pn均降低,与HM相比,在LM下下降更显著。在7—9月的高温条件下,早熟禾地上部分、根系和土壤R高于Pn;但在美国新泽西州较冷的季节（5—6月） Pn高于R。研究表明,较低的修剪高度尤其是在高温条件下降低了草坪草Pn,季节性温度变化下可以通过改变修剪高度影响成熟草坪草的生长,从而缓解高温对草坪生长带来的不利影响。     

草坪草药剂修剪的应用研究进展

药剂剪草又称化学剪草 ,是指利用生长调节物质或除草剂控制草坪草生长 ,达到减少草坪修剪的目的 ,从而降低养护管理成本。药剂剪草主要是基于化学药剂 (生长调节物质 )对草坪草的生物学效应。其效应在植株形态上表现为矮化、促蘖。化学药剂还使草坪草在内源激素、酶系统、代谢水平等方面发生深刻的变化。药剂剪草技术研究主要集中于高效低毒的药剂或药剂组配的筛选、药剂浓度的筛选。研究认为 ,不同的草种对化学药剂的敏感程度不同。为增强药效 ,可采取药剂混配、增加施药频率以及将药剂剪草和机械剪草有机结合起来等措施     

生长延缓剂在草坪草上的应用研究进展

阐述了生长延缓剂对草坪草生长发育和抗逆性的影响研究,揭示了生长延缓剂可以有效地降低草坪草修剪频率、延长绿期和减少管理费用,并提高草坪草对光照、温度、水分的利用率和病害胁迫的抵抗能力,指明生长延缓剂在草坪生产实践中具有广泛的应用前景.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

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

Tropical Animal Health and Production -