低能N+介导大豆全DNA转入紫花苜蓿的初步研究

研究了不同剂量N 注入及低能N 介导大豆全DNA转入紫花苜蓿种子后,其发芽率、叶粗蛋白质含量及叶绿素含量等生理生化指标的变化规律。实验结果表明:在低剂量范围内(0～2.08×1016N /cm2),N 注入对紫花苜蓿种子存在当代刺激效应。剂量在6.24×1016～8.32×1016N /cm2范围内,N 注入对紫花苜蓿种子存在反常辐照损伤效应。随着N 注入剂量增加,各生理生化指标先降后升再降。紫花苜蓿种子经离子束注入刻蚀、加工处理,再用大豆基因组DNA浸泡后,M2总性状突变率达到19.8%,其中3株叶粗蛋白质含量比对照高约0.5%、1株叶绿素含量比对照高33.3%。     

N+注入对甘草种子萌发和根发育效应及作用机制

甘草种子注入25 keV,剂量≤4.68×1016 个/cm2 N 对种子萌发的成活率和根发育表现为刺激效应,更高剂量的N 注入表现出"损伤-修复-损伤"的效应趋势,表明离子注入的能量沉积和动量传递效应产生的自由基伤害与质量沉积和电荷的中和效应对自由基的清除是一个动态反应过程.25 keV,4.68×1016 个/cm2 N 注入能提高甘草种子萌发成活率,促进根发育,提高幼苗的耐旱特性,可用于沙漠植被甘草种子的前处理.     

低能N~+束诱发对狗牙根种子发芽能力的影响

探索低能N+束对狗牙根(Cynodon dactylon)的诱变效应及其机理,研究M1代种子发芽状况为确定其适宜的诱变参数奠定基础。通过LZD-1000离子注入机将N+束注入狗牙根干种子,研究N+束引起种子发芽能力的变化。结果表明,注入一定剂量的N+束可以促进狗牙根种子发芽,但注入时间以5 s为宜,超过5 s其发芽能力急剧下降。5 s注入时间下6种剂量处理的种子发芽率、发芽势和活力指数均值分别高出对照10%、9%和16,10 s注入时间下3项指标均值分别低于对照55%、15%和134,不同剂量对种子发芽率、发芽势及活力指数的影响存在显著差异(3项指标F值分别为638.13、109.31和2.16,均大于F0.05(12,26)=2.15)。在20 keV能量下,注入时间为5 s和剂量为80×1014ions/cm2是N+束注入诱变狗牙根育种最有效的诱变参数,可诱使狗牙根种子萌发状况发生较大的变异。     

复合诱变选育高产β-葡聚糖酶菌株

以黑曲霉SD16为出发菌株,经紫外线和N 注入诱变处理,选育高产β-萄聚糖酶菌株.结果表明:紫外线的最佳照射时间为10min,N 最佳注入剂量为70×2.6×1012 N /cm2;突变高产菌株AN1的β-葡聚糖酶酶活由出发菌株SD16的493.2 U/mL提高到902.5 U/mL.且突变菌株AN1经传5代培养,产酶性能稳定.     

空间搭载对2个紫花苜蓿品种过氧化物酶同功酶的影响

经神州3号飞船搭载的2个紫花苜蓿品种阿尔冈金和三得利种子,种植后出现矮化植株,阿尔冈金和三得利分别选取9株和8株,利用聚丙烯酰胺凝胶垂直板电泳技术对这些单株及其对照进行过氧化物酶同工酶分析,结果表明:阿尔冈金和三得利的酶谱带数为5～7条,在相对迁移率(Rf)17.93％处,所选单株都有谱带出现,此带为2个品种的公共带;...     

氮离子束注入对甜高粱植株过氧化物同工酶(POD)及主要性状表现的影响

利用不同剂量氮离子束注入方法处理甜高梁Della和Keller两个品种的干种子,对植株过氧化物同工酶(POD)酶谱进行分析;考查M1代田间出苗率、株高、茎粗、主茎节数、糖锤度和鲜草产量等6个性状,并对不同品种材料M1代性状表现和不同注入剂量对甜高粱M1代性状的影响进行双因素方差分析.结果表明:①离子束注入引起了POD的差异,且不同剂量处理的种子后代植株任POD酶谱特征上有所不同。②从生理生化角度研究氮离子束注入对两种甜高粱的影响,用田间出苗率、株高、茎粗、主茎节数、糖锤度和鲜草产量等6个性状指标研究甜高粱对氮离子束注入的敏感性问题,得到田间出苗率和茎粗随着注入剂量呈现先下降后上升再下降的"马鞍型"曲线。③离子注入不仅在不同品种之间M1代性状差异明显,而且不同剂量处理和对照(CK)之间性状表现差异显著,影响各度各不相同。     

两种诱变处理对紫花苜蓿种子萌发及植株生理生化特性的影响

为了研究诱变处理对紫花苜蓿(Medicago sativa)种子萌发及植株生理特性的影响,以紫花苜蓿Wega7F种子为供试材料,经~(60)Co-γ和甲基磺酸乙酯(EMS)两种诱变处理后,测定种子萌发、幼苗生长及植株生理指标。结果表明,不同剂量~(60)Co-γ射线处理对苜蓿萌发率、发芽指数、幼苗生长的影响不同,低剂量(150Gy)提高了发芽率、发芽指数及幼苗生长,高剂量(300和450Gy)抑制萌发率和幼苗生长。EMS处理均抑制苜蓿种子的萌发及幼苗生长。在低剂量条件下,~(60)Co-γ射线处理对株高有促进作用,高剂量会抑制植株生长;EMS处理则抑制苜蓿株高生长。两种诱变处理均促进苜蓿分枝,且低剂量处理下均有利于提高苜蓿单株鲜草产量。在~(60)Co-γ辐射和0.4%EMS处理下,叶绿素含量提高,其他处理叶绿素含量均降低。诱变提高了苜蓿叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,对3种酶活性的影响程度表现为PODCATSOD。本研究结果表明,150Gy ~(60)Co-γ对苜蓿产量及株高影响显著,为苜蓿生产应用提供了一定利用价值;EMS处理更有利于增强苜蓿分枝能力,有利于苜蓿在观赏方面的提高及改良。     

转红树总DNA紫花苜蓿T1代耐盐株系的生理生化特性分析

以花粉管通道法转红树总DNA紫花苜蓿阿尔冈金T₁代耐盐植株幼苗为材料,经300 mmol/L NaCl处理后,测定叶绿素、脯氨酸、丙二醛含量和抗氧化酶活性等耐盐相关生理生化指标。结果显示,转基因株系叶绿素含量下降0.09~0.29倍,而对照植株下降0.32倍;转基因株系脯氨酸含量升高1.2~4.2倍,对照植株的脯氨酸升高0.9倍;转基因株系丙二醛含量升高0.15~0.29倍,对照植株的丙二醛含量升高0.36倍;转基因株系超氧化物歧化酶活性升高0.20~0.25倍,对照植株的超氧化物歧化酶活性升高0.19倍;转基因株系过氧化物酶和过氧化氢酶活性分别是对照的1.6~5.6倍和1.2~1.3倍。转基因株系表现出耐盐植物的生理生化特性。     

6个紫花苜蓿品种在广西地区的适应性比较试验

为了筛选适宜广西种植的紫花苜蓿品种,试验采用随机区组方法,以6个国内外耐热紫花苜蓿(Medicago sativa)品种WL903、WL712、WL525HQ、59N59、精英9级和龙威6010为研究对象,测定了各苜蓿品种的生长性能、营养价值及越夏率等指标。结果表明:株高及鲜草产量表现较好的紫花苜蓿品种是59N59与WL903,株高分别达到62.01 cm、62.53 cm,鲜草产量分别达到40.93 t/hm~2、38.38 t/hm~2,与表现较差的龙威6010差异极显著(P0.01)。各试验品种营养价值都较好,粗蛋白含量均达20%以上,其中精英9级粗蛋白含量高达28.43%。6个紫花苜蓿品种的越夏率均高于75%。说明在本试验区生长快、产量高、营养价值较高、越夏率高的紫花苜蓿品种为59N59和WL903,适宜作为广西地区推广种植的首选品种。     

不同剂量~(60)Co-γ射线辐射对NaCl胁迫下紫花苜蓿幼苗营养成分的影响

为了探究不同剂量~(60)Co-γ射线辐射的紫花苜蓿种子发芽后的幼苗在NaCl胁迫下各营养成分的变化情况,试验以~(60)Co-γ射线辐射的紫花苜蓿种子为材料,进行了幼苗培养和幼苗的NaCl胁迫处理,测定了幼苗的营养成分含量并进行了相关性和隶属函数分析。结果表明:600 Gy辐射剂量下,紫花苜蓿幼苗的相对含水量、粗蛋白、粗脂肪、粗纤维和粗灰分含量均达最大值,分别比对照组增加了2.68%、10.71%、10.74%、7.38%和4.71%;各营养成分含量间均呈正相关,粗蛋白、粗脂肪和粗纤维三者间呈极显著正相关(P0.01); 600～900 Gy的辐射剂量可促进紫花苜蓿幼苗营养成分的积累,而1 200～1 500 Gy的辐射剂量对紫花苜蓿幼苗营养成分产生一定的破坏作用。说明可采用低剂量~(60)Co-γ射线辐射处理来提高盐碱地紫花苜蓿的品质。     

鱼肌肉中磺胺二甲嘧啶及其代谢产物的高效液相色谱法测定

研究了鲟鱼肌肉中磺胺二甲嘧啶及其主要代谢物N4 乙酰化磺胺二甲嘧啶的高效液相色谱测定法。样品用乙腈提取,正己烷脱脂,碱性氧化铝SPE柱净化,高效液相色谱 Inertsil ODS 3(4 6 mm×250 mm, 粒径 5μm),流动相:水 乙腈 乙酸(76∶24∶0 05, V/V/V)测定。在 20、100、2 000μg/kg 的添加浓度,测得 SM2、N4 ACE SM2 的平均回收率范围分别为80 4%~85.3%、88.4%~96.0%;2种药物的检测限均为10μg/kg。     

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.     

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.     

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