Effect of high intensity training on anaerobic capacity of middle gluteal muscle in Thoroughbred horses

We hypothesize that high intensity training for Thoroughbred horses that have been subjected to conventional training could further improve the metabolic properties of the middle gluteal muscle. Nine well-trained horses were subjected to high intensity (80-100% Vdot;O(2)max, 5 minx2) training for 12 weeks. Biopsy samples were obtained from the muscle before and after 4 and 12 weeks of training. Three of the 9 horses did not complete the training programme. In the remaining 6 horses, activities of succinic dehydrogenase (SDH), phosphofructokinase (PFK) and 3-hydroxy acyl CoA dehydrogenase (HAD), and the composition of myosin heavy chain isoforms were analyzed by biochemical techniques. After 12 weeks of training, a significant increase was found in PFK activity but not in the SDH and HAD activities. There were no significant changes in the composition of myosin heavy chain isoforms. The high intensity training in this study was effective at increasing glycolytic enzyme activity, indicating the possibility to improve anaerobic capacity, which potentially could contribute greatly to performance in Thoroughbred horses. This study also highlighted a fact that high intensity training should be given with the great care to prevent the skeletal muscle injuries.     

不同施肥处理对黄泥土微生物生物量碳氮和酶活性的影响

通过室内培育实验,研究了不同施肥处理对黄泥土微生物生物量C、N和脲酶、酸性磷酸酶、蔗糖酶活性的影响。培养过程中,单施化肥处理土壤微生物生物量C、N均呈下降趋势,施用有机肥处理的土壤微生物量C前期升高至一定水平后或保持稳定、或呈下降趋势,而微生物生物量N总体均呈下降趋势;不同施肥处理的脲酶活性呈前期上升后期下降趋势,而酸性磷酸酶和蔗糖酶则单施化肥处理呈上升趋势、配施有机肥处理呈下降趋势。与对照处理相比,单施化肥处理显著降低土壤微生物生物量C、N,高量施用化肥处理还显著降低土壤脲酶活性,但对酸性磷酸酶和蔗糖酶活性的影响并不明显。秸秆施用可显著提高土壤微生物生物量C、N和酶活性,特别是高量施用秸秆的效果更明显。施用猪粪由于同时带入了大量的活性养分,对土壤微生物生物量C、 N和酶活性的影响尚难评价。在高度集约农业利用下,继续保持较高的化肥施用量并不利于土壤生物质量的维护和提高,而秸秆直接还田才是保持土壤健康状态的有效措施。     

高温胁迫下高羊茅草坪草生理特性研究

从美国引进的39个高羊茅草坪草种分成了5个生态类型,在1999—2000年从每类中找出一个具有典型性状的草种,测定其周年草坪坪质表现、根系活力、叶片可溶性糖含量变化,同时测定各类草种在高温胁迫下保护酶活性与质膜透性的变化。结果表明,根系活力及可溶性糖含量在一定程度上影响着草坪坪质的周年变化。同时,草坪草叶片MDA含量的增长率和草坪草叶片的质膜透性增长率具有显著的正相关效应。在40℃高温胁迫下,草坪草叶片SOD与POD相对活性和MDA含量的增长率及PMP增长率具有显著的负相关效应,5个草种对高温的抗性能力大小顺序是:Gooden>Regi ment>Tomahawk>SR-8210>Brandy。在此基础上,最后对草坪草抗性的准确快速检测方法进行了讨论。     

Comparative antifungal activities and biochemical effects of monoterpenes on plant pathogenic fungi

The antifungal activity of twelve monoterpenes, camphene, (R)-camphor, (R)-carvone, 1,8-cineole, cuminaldehyde, (S)-fenchone, geraniol, (S)-limonene, (R)-linalool, (1R,2S,5R)-menthol, myrcene and thymol was evaluated against four plant pathogenic fungi Rhizoctonia solani, Fusarium oxysporum, Penecillium digitatum and Asperigallus niger by using mycelial growth inhibitory technique. (S)-limonene and thymol were examined for their inhibitory effects on pectin methyl esterase (PME), cellulase and polyphenol oxidase (PPO) of tested fungi. Thymol was the most potent antifungal compound against the four test fungi with EC₅₀ values of 33.50, 50.35, 20.14 and 23.80 mg/L on R. solani, F. oxysporum, P. digitatum and A. niger, respectively. The antifungal activity of thymol was comparable to a reference fungicide, carbendazim. (S)-limonene and 1,8-cineole exhibited pronounced antifungal activity against the four tested fungi. The most effective antifungal compounds thymol and (S)-limonene showed strong inhibitory effect on the activity of PME and cellulase but revealed no inhibitory effect on PPO. The results showed that PME was more sensitive than cellulase to thymol and (S)-limonene. This is the first report on the inhibitory effects of monoterpenes thymol and (S)-limonene on PME, cellulase and PPO. The results indicated that monoterpenes may cause their antifungal activity by inhibiting PME and cellulase. The strong antifungal activity of thymol, (S)-limonene and 1,8-cineole reported in this study indicated that these compounds have a potential to be used as fungicides.     

黄蓝状菌几丁质酶基因tfchi1的克隆、表达及抗菌活性

 为研究黄蓝状菌（Talaromyces flavus）几丁质酶性质和作用,通过RT PCR、3′ RACE及5′ TAIL PCR技术克隆了一个黄蓝状菌几丁质酶基因tfchi1,该基因全长为2 561 bp,含有6个内含子,包含一个1 194 bp的ORF,编码397个氨基酸,分子量为43.47 kDa,属于糖苷水解酶第18家族。利用基因重组的方法构建酵母分泌型表达载体pPIC9K/tfchi1,并转化毕赤酵母,筛选得到一株高效表达几丁质酶的工程菌GS TFCHI1 9,甲醇诱导第7 d酶活性最高,达32.29 U·mL-1。SDS PAGE检测纯化重组蛋白的分子量约44 kDa。重组几丁质酶Tfchi1最适反应温度为35℃,最适反应pH值为5.5,在pH 6～8之间稳定。Zn2+、Cu2+对 Tfchi1活性有明显的抑制作用。抑菌活性测定结果显示,Tfchi1可明显抑制敏感植物病原真菌的菌丝生长和分生孢子萌发。该酶在几丁质资源的开发利用和生物防治等领域具有较广的应用前景。     

具有除草活性的小麦根腐病菌发酵条件优化

通过单因子试验和正交试验对小麦根腐病菌菌株进行了发酵条件优化,以提高其活性物质的产量。结果表明:最适合小麦根腐病菌产毒的培养基是察氏培养基;该培养基的最佳碳源为葡萄糖,氮源为氯化铵,无机盐为氯化钾、磷酸氢二钾、硫酸镁和硫酸亚铁;发酵培养基各组分的最佳配比为:葡萄糖2.0%,氯化铵0.25%,氯化钾0.05%,磷酸氢二钾0.025%,硫酸镁0.025%,硫酸亚铁0.000 5%;有利于提高菌株活性物质产量的培养条件为初始pH7.0,转速为130r/min,温度为28℃,培养时间为5d,装液量为120mL/250mL,接种量为6%。小麦根腐病菌菌株发酵产物具有良好的热稳定性和光稳定性,在弱酸性及中性条件下较稳定。发酵条件优化后提高了小麦根腐病菌的除草活性。     

拮抗茄子黄萎病菌土壤放线菌的分离筛选和鉴定

为了研究土壤拮抗性放线菌对茄子黄萎病的生防价值,从陕西省延安市宝塔区与汉中地区土壤中分离、纯化获得154株具有纤维素降解活性的放线菌。采用平板对峙培养法进行初筛,用生长速率法对抑菌效果较好的菌株ZX-10-4进行抑菌谱的测定,并进行盆栽试验验证其对茄子黄萎病的防治效果,通过形态、培养特征及16S rDNA序列分析研究其分类地位。结果显示,有17株放线菌对茄子黄萎病菌抑菌效果较好且抑菌活性稳定,其中菌株ZX-10-4的抑菌活性最高,抑菌率达90.15%;活性菌株ZX-10-4发酵原液对茄子黄萎病的保护和治疗作用分别为70.00%和60.33%,稀释5倍液的防效也在50%以上。根据形态、培养特征、生理生化指标和16S rDNA序列分析,初步确定菌株ZX-10-4为白网链霉菌Streptomyces albireticuli的近似种。     

烟草黑胫病拮抗根际芽胞杆菌FB-16的筛选鉴定及其抑菌活性

为获得对烟草黑胫病有较强生防效果的拮抗细菌,从健康烟草根际采集30份土壤样品,分离纯化得到347株细菌,经病原真菌定向筛选后得到1株对烟草黑胫病菌等病原真菌拮抗活性较好的细菌FB-16,其对烟草黑胫病菌的抑菌带宽为23mm。采用菌丝生长速率法、作用机制试验、温室防病试验测定FB-16的抑菌作用,并通过形态学特征、生理生化特征及16S rDNA序列分析对菌株进行鉴定。结果显示,菌株FB-16发酵液对烟草黑胫病菌菌丝生长抑制率为95.96%;其代谢产物对烟草黑胫病菌菌丝有致畸作用;菌株FB-16为解淀粉芽胞杆菌Bacillus amyloliauefaciens(Gen-Bank登录号为JN245982);饱和度25%硫酸铵获得的抑菌物质对烟草黑胫病菌的抑菌活性较高,抑菌圈直径达42.00 mm;FB-16活性产物处理的烟草植株在接种烟草黑胫病菌7天后的防治效果为69.96%。表明菌株FB-16在烟草黑胫病生物防治中具有潜在的利用价值。     

古尔班通古特沙漠地衣结皮对放牧踩踏干扰的小尺度响应

古尔班通古特沙漠地衣结皮对放牧踩踏干扰及其所引起的生境异质性具有重要的指示作用。研究表明：① 放牧踩踏干扰主要集中于结皮层（0~5 cm）,随机调查的样方中,90%的样方干扰率均低于30%,生物土壤结皮(BSCs)破损尚处于较安全的范围;② 放牧踩踏干扰降低了BSCs总盖度,不同类型的结皮对践踏干扰的反应具差异性,其中,真菌-藻类共生形成的地衣结皮与干扰率呈极显著负相关（P<0.01）,干扰率>30%的样方中,抗风蚀能力较强的苔藓结皮、地衣结皮盖度均显著低于未受干扰样方,地衣共生体的破坏导致真菌数量显著增加（P<0.05）;③ 有机质、土壤容重等土壤理化指标均与干扰率呈负相关,干扰率>30%的样方中各指标均低于未受干扰样方。其中,土壤容重是对放牧干扰比较敏感的指标,与地衣结皮盖度亦呈极显著正相关（P<0.01）,与流沙盖度呈显著负相关（P<0.05）。     

连钱草萃取物对4种植物病原真菌抑菌活性的测定

通过超声波提取法和液液分配萃取法制备连钱草萃取物,采用生长速率法测定连钱草萃取物对4种植物病原真菌的抑菌活性。结果表明：连钱草的石油醚萃取物和氯仿萃取物对苹果腐烂病菌、棉花立枯病菌、黄瓜枯萎病菌、番茄灰霉病菌等4种植物病原真菌均有较强的抑制活性,其中氯仿萃取物对棉花立枯病菌的抑制作用最强,EC50为0.619 3mg/mL。石油醚萃取物对4种植物病原真菌的EC50分别为：0.837 3、3.517 8、1.496 0、2.3517mg/mL,氯仿萃取物对4种植物病原真菌的EC50分别为：0.619 3、4.458 6、1.689 8、1.556 3mg/mL。