丝孢酵母与钙和杀菌剂配合对苹果采后病害的抑制效果(英文)

研究一种从桃果实上分离获得的拮抗菌———丝孢酵母 (Trichosporonsp .)对苹果 (MalusdomesticaBorkh .)采后病害的防治效果 ,包括接种不同浓度的拮抗菌与不同病菌之间的拮抗作用 ,以及拮抗菌与钙或与杀菌剂配合对苹果灰霉病和青霉病的抑制效果。结果表明 ,拮抗菌和病菌孢子的浓度都明显地影响其抑菌效果。拮抗菌的使用浓度越大 ,病菌孢子的接种浓度越低 ,其抑病效果越好。当丝孢酵母菌的使用浓度达到 10 8colony_formingunits(CFU) /mL时 ,可完全抑制接种在苹果上的灰霉菌 (BotrytiscinereaPers.)和青霉菌 (Penicilliumexpansum (Link)Thom)(<10 6spores/mL)的致病力。用 10 6～ 10 7CFU/mL的丝孢酵母与 5 0 μL/L的扑海因配合对苹果采后灰霉病和青霉病的抑制效果明显地好于单独使用相同剂量的拮抗菌或杀菌剂。在丝孢酵母的悬浮液中加入 1%～ 2 ?Cl2 可显著地提高拮抗菌对灰霉病和青霉病的抑制效果。     

香蕉抗(感)病品种根系分泌物对枯萎病菌和枯草芽孢杆菌的生物效应

为明确香蕉根系分泌物对枯萎病菌及其生防枯草芽孢杆菌的生物效应,采用离位溶液培养法收集抗枯萎病香蕉品种(南天黄)和感枯萎病香蕉品种(桂蕉6号)的根系分泌物,研究根系分泌物对土壤微生物种群数量、香蕉枯萎病菌和枯草芽孢杆菌生长的影响。结果表明: 抗病品种根系分泌物能显著减少土壤真菌的数量,抑制枯萎病菌孢子的萌发;而感病品种根系分泌物能显著促进病菌菌丝生长和孢子的萌发,两个品种根系分泌物均能显著促进枯草芽孢杆菌的生长和生物膜形成。经抗(感)病香蕉品种根系分泌物处理,病菌菌丝生长速率分别为11.28和12.28 mm·d^-1,病菌孢子的萌发率分别为34.6%和79.5%;枯草芽孢杆菌培养12 h后菌体生长量的OD₆₀₀分别为1.27和1.14,生物膜形成量在静置培养72 h后OD₅₇₀分别达1.11和1.30,两个品种处理间的差异均达显著水平。枯草芽孢杆菌在香蕉感病品种根际中定殖的菌量显著高于抗病品种。通过对两个品种根系分泌物中可溶性总糖、游离氨基酸和有机酸的含量和组成分析,发现抗病品种根系分泌物中有机酸和游离氨基酸的含量明显高于感病品种,在各组成成分中,以乙酸和脯氨酸在抗(感)病香蕉品种根系分泌物中含量比值较高,分别达3.7和2.4倍。综上所述,抗病品种根系分泌物能抑制病菌生长,感病品种根系分泌物则会显著促进病菌生长,而两个品种根系分泌物均能显著促进枯草芽孢杆菌的生长和生物膜的形成。     

人参(Panax ginseng)根系分泌物成分对人参致病菌的化感效应

采用室内培养结合生物学测定的试验方法,研究了不同浓度人参(Panax ginseng)根系分泌物成分苯甲酸、邻苯二甲酸二异丁酯、十六酸和2,2-二(4-羟苯基)丙烷对人参立枯丝核菌(Rhizoctonia solani)、黑斑菌(Alternaria panax)、疫病菌(Phytophthora cactorum)、菌核菌(Sclerotinia schinseng)、锈腐菌(Cylindrocarpon destructans)和绿色木霉菌(Trichoderma viride)菌落生长及孢子萌发的化感效应.结果显示,不同浓度人参根系分泌物成分对人参致病菌及绿色木霉菌的化感效应存在显著差异.苯甲酸浓度与人参立枯丝核菌、菌核菌和锈腐菌菌落生长以及人参黑斑菌、锈腐菌孢子萌发呈负相关,与人参黑斑菌、绿色木霉菌菌落生长呈正相关;对人参疫病菌菌落生长的化感效应表现为低浓度和高浓度抑制,中浓度促进.邻苯二甲酸二异丁酯浓度与人参立枯丝核菌、黑斑菌、菌核菌和绿色木霉菌菌落生长以及人参黑斑菌孢子萌发呈负相关;对人参锈腐菌菌落生长和孢子萌发表现为低浓度和高浓度抑制,中浓度促进;对人参疫病菌菌落生长表现为低浓度和中浓度抑制,高浓度促进.2,2-二(4-羟苯基)丙烷浓度与人参立枯丝核菌、黑斑菌、疫病菌、绿色木霉菌菌落生长以及人参黑斑菌、锈腐菌孢子萌发呈负相关;对人参菌核菌、锈腐菌菌落生长表现中浓度促进,高浓度抑制.十六酸浓度与人参锈腐菌、疫病菌和绿色木霉菌菌落生长呈正相关,与人参锈腐菌孢子萌发呈负相关,对黑斑菌孢子萌发表现为中浓度抑制.4种根系分泌物的等量混合物浓度与人参致病菌及拮抗木霉菌菌落生长速率呈负相关.     

丝孢酵母与钙与杀菌剂配合对苹果采后病害的抑制效果

研究一种从桃果实上分离获得的拮抗菌－丝孢酵母（Trichosporon sp.)对苹果（Malus domestica Borkh.)采后病害的防治效果,包括接种不同浓度的拮抗菌与不同病菌之间的拮抗作用,以及拮抗菌与钙或与杀菌剂配合对苹果灰霉病和青霉病的抑制效果。结果表明,拮抗菌和病菌孢子的浓度都明显地影响其抑菌效果。拮抗菌的使用浓度越大,病菌孢子的接种浓度越低,其抑病效果越好。当丝孢酵母菌的使用浓度达到1068colony-forming units(CFU)mL时,可完全抑制接种在苹果上的灰霉菌（Botrytis cinerea Pers.)和青霉菌（Penicillium expansum(Link)Thom)的抑制效果明显地好于单独使用相同剂量的拮抗菌或杀菌剂。因丝孢酵母的悬液液中加入1％－2％CaCl2可显地提高拮抗菌对灰霉病和青霉病的抑制效果。     

甘蓝根肿病菌的生物学特性研究*

对甘蓝根肿病菌生物学特性研究表明,该菌休眠孢子萌发的最适温度24℃,最适pH值6.0～6.7,致死温度45℃,肿根腐烂处理可以显著提高萌发率,光对休眠孢子萌发有明显抑制作用。该菌休眠孢子在感病寄主的根分泌物溶液中萌发率最高,达75%。耐病甘蓝品种及番茄的根分泌物均能刺激休眠孢子萌发。通过电镜观察,根肿病菌休眠孢子为近球形,孢壁有乳状突起,直径2.1～3.1mm(平均直径2.5mm)。游动孢子为近球形或椭圆形,大小为1.6～3.6mm,同侧着生不等长尾鞭式双鞭毛。     

大豆猝死综合症病菌枝状镰孢的活性检测研究

应用来源于美国、阿根廷的我国对外检疫性有害生物大豆猝死综合症病菌枝状镰孢Fusarium virguliforme共8个菌株,分别在43℃至47℃ 5个温度梯度下水浴处理1min至5min 5个时间梯度,荧光染色后,经单细胞微量分析系统进行活性检测分析,设置传统萌发试验作为对照,结果表明:该病菌在47℃水浴处理4min即全部失活,SPSS统计分析得出该病菌的活性检测值与处理温度呈极显著负相关,而与处理时间(除菌株2-1和22825呈显著负相关外)均呈极显著负相关;所设置的孢子萌发率与处理温度和处理时间之间也呈极显著负相关;活性检测值与萌发率两者之间具有极显著的正相关性.本研究表明活性检测可以替代传统的孢子萌发方法,从而大幅度缩短该病菌活性检测时间,明显提高检测效率.     

甘蓝根肿病菌的生物学特性研究

对甘蓝根肿病菌生物学特性研究表明,该菌休眠孢子萌发的最适温度24℃,最适pH值6.0-6.7,致死温度45℃,肿根腐烂处理可以显著提高萌发率,光对休眠孢子萌发有明显抑制作用。该菌休眠孢子在感病寄主的根分泌物溶液中萌发率最高,达75％,耐病甘蓝品种及番茄的根分泌物均能刺激休眠孢子萌发。通过电镜观察,根肿病菌休眠孢子为近球形,孢壁有乳状突起,直径2.1-3.1μm（平均直径2.5μm)。游动孢子为近球形或椭圆形,大小为1.6-3.6μm。同侧着生不等长尾鞭式双鞭毛。     

纳他霉素对芒果采后胶孢炭疽菌的抑菌效果及机理

以纳他霉素为抑菌剂, 实验测定了离体条件下不同浓度纳他霉素对胶孢炭疽菌(Colletotrichum gloeosporioides)的孢子萌发及菌丝生长的抑制效果, 以及活体损伤接种炭疽病菌后, 纳他霉素对芒果(Mangifera indica)果实炭疽病的防治效果。通过测定纳他霉素处理后胶孢炭疽菌的细胞膜相对渗透率、可溶性蛋白含量、细胞膜完整性、孢子内活性氧水平和线粒体分布情况, 初步探明其抑菌机理。结果表明, 3 mg∙L ^-1纳他霉素可显著抑制胶孢炭疽菌孢子萌发、芽管伸长和菌落生长, 80 mg∙L ^-1纳他霉素可有效抑制芒果贮存过程中果实炭疽病斑的扩展。纳他霉素处理后胶孢炭疽菌细胞膜相对渗透率和可溶性蛋白含量增加; 2 mg∙L ^-1纳他霉素处理8小时, 处理组胶孢炭疽菌孢子细胞膜损伤染色率为33.6%, 对照组染色率为13.9%; 处理组胞内活性氧产生染色率达46.9%, 比对照组高39.7%; 同时观察到纳他霉素使胞内线粒体分布不均且荧光信号微弱。以上结果表明, 纳他霉素可以破坏胶孢炭疽病菌细胞膜, 诱导活性氧大量积累, 并降低线粒体活性, 从而干扰菌体正常生理活性, 使其代谢活动受影响, 从而达到抑菌目的。     

苹果树腐烂病菌拮抗放线菌的筛选、鉴定及防效

以苹果树腐烂病菌为靶标菌,通过对峙法和生长速率法对分离自苹果树根际土壤的放线菌进行筛选,对筛选出的拮抗菌株通过形态学和分子生物学特征进行鉴定,并测定了拮抗菌ZZ-9发酵滤液对苹果树腐烂病菌孢子萌发和菌丝生长的影响及离体枝条防效.结果表明: 经对峙初筛,15株放线菌对苹果树腐烂病菌具有抑菌作用,占所分离株数的18.8%,其中抑制率>50%的有8株.复筛结果表明,ZZ-9对腐烂病菌抑制率最高,达96.4%,显著高于其他菌株;通过培养特征、生理生化特性及16S rDNA序列分析将菌株ZZ-9初步鉴定为娄彻氏链霉菌,其在GenBank上的序列登录号为KT986228;不同稀释倍数的ZZ-9发酵滤液对腐烂病孢子萌发及菌丝生长均有明显的抑制作用,其中50倍发酵滤液对孢子萌发抑制率和菌丝生长抑制率均达80%以上,且受抑制菌丝颜色加深,分支增多,末端膨大、畸形,出现原生质浓缩与释放现象;离体枝条防效试验表明,菌株ZZ-9发酵原液对苹果树腐烂病防效可达75%以上,表明该菌株可作为防治苹果树腐烂病的生防菌株.     

纳他霉素对芒果采后胶孢炭疽菌的抑菌效果及机理

以纳他霉素为抑菌剂, 实验测定了离体条件下不同浓度纳他霉素对胶孢炭疽菌(Colletotrichum gloeosporioides)的孢子萌发及菌丝生长的抑制效果, 以及活体损伤接种炭疽病菌后, 纳他霉素对芒果(Mangifera indica)果实炭疽病的防治效果。通过测定纳他霉素处理后胶孢炭疽菌的细胞膜相对渗透率、可溶性蛋白含量、细胞膜完整性、孢子内活性氧水平和线粒体分布情况, 初步探明其抑菌机理。结果表明, 3 mg?L ^-1纳他霉素可显著抑制胶孢炭疽菌孢子萌发、芽管伸长和菌落生长, 80 mg?L ^-1纳他霉素可有效抑制芒果贮存过程中果实炭疽病斑的扩展。纳他霉素处理后胶孢炭疽菌细胞膜相对渗透率和可溶性蛋白含量增加; 2 mg?L ^-1纳他霉素处理8小时, 处理组胶孢炭疽菌孢子细胞膜损伤染色率为33.6%, 对照组染色率为13.9%; 处理组胞内活性氧产生染色率达46.9%, 比对照组高39.7%; 同时观察到纳他霉素使胞内线粒体分布不均且荧光信号微弱。以上结果表明, 纳他霉素可以破坏胶孢炭疽病菌细胞膜, 诱导活性氧大量积累, 并降低线粒体活性, 从而干扰菌体正常生理活性, 使其代谢活动受影响, 从而达到抑菌目的。     

PRO-LONG涂膜对采后贮藏荔枝果实色泽和酶活性变化的影响

本文以荔枝品种“槐枝”为材料,以1．5％和2．5％Pro-long涂膜处理果实,研究Pro-long涂膜对果后贮于4℃的荔枝果皮色泽变化和有关酶活性的变化。对照和处理的HunterL值和b值均随贮藏时间的延长而降低,处理的比对照的下降慢。采后贮藏开始21d内,对照和处理的HuntCra值变化很小,保持相对稳定,之后的贮藏时间内有较显著的下降,说明贮藏初期果实的红色特性变化较少,之后变化很明显,这与果皮花色素苷、类黄酮、总酚的变化是相对应的。在贮藏后期,处理的HuntCra值下降明显较对照慢。Hunter值的变化与在贮藏过程中果实外观逐渐变成暗红和揭变以及在果实的来后根变中起着重要作用的多酚氧化酶和部分地涉及褐变过程的过氧化物酶的变化相对应。处理的过氧化物酶活性增加较对照慢,而且,与对照比较,多酚氧化酶的峰值稍稍延迟了。未发现l‘5％和2．5％处理间有明显差别。因此,Pro-long涂胶对荔枝的应用可以部分地降低多酚氧化酶和过氧化物酶,影响果皮花色素苷的降解、类黄酮和总酚的变化,延迟了褐变过程的发生。     

Pre-sowing magnetic treatments of tomato seeds increase the growth and yield of plants

The effects of pre-sowing magnetic treatments on growth and yield of tomato (cv Campbell-28) were investigated under field conditions. Tomato seeds were exposed to full-wave rectified sinusoidal non-uniform magnetic fields (MFs) induced by an electromagnet at 100 mT (rms) for 10 min and at 170 mT (rms) for 3 min. Non-treated seeds were considered as controls. Plants were grown in experimental plots (30.2 m(2)) and were cultivated according to standard agricultural practices. During the vegetative and generative growth stages, samples were collected at regular intervals for growth rate analyses, and the resistance of plants to geminivirus and early blight was evaluated. At physiological maturity, the plants were harvested from each plot and the yield and yield parameters were determined. In the vegetative stage, the treatments led to a significant increase in leaf area, leaf dry weight, and specific leaf area (SLA) per plant. Also, the leaf, stem, and root relative growth rates of plants derived from magnetically treated seeds were greater than those shown by the control plants. In the generative stage, leaf area per plant and relative growth rates of fruits from plants from magnetically exposed seeds were greater than those of the control plant fruits. At fruit maturity stage, all magnetic treatments increased significantly (P < .05) the mean fruit weight, the fruit yield per plant, the fruit yield per area, and the equatorial diameter of fruits in comparison with the controls. At the end of the experiment, total dry matter was significantly higher for plants from magnetically treated seeds than that of the controls. A significant delay in the appearance of first symptoms of geminivirus and early blight and a reduced infection rate of early blight were observed in the plants from exposed seeds to MFs. Pre-sowing magnetic treatments would enhance the growth and yield of tomato crop.     

Effects of pyridostigmine bromide on human thermoregulation during cold water immersion

This study examined the effects of an oral 30-mg dose of pyridostigmine bromide (PYR) on thermoregulatory and physiological responses of men undergoing cold stress. Six men were immersed in cold water (20 degrees C) for up to 180 min on two occasions, once each 2 h after ingestion of PYR and 2 h after ingestion of a placebo. With PRY, erythrocyte cholinesterase inhibition was 33 +/- 12% (SD) 110 min postingestion (10 min preimmersion) and 30 +/- 7% at termination of exposure (mean 117 min). Percent cholinesterase inhibition was significantly related to lean body mass (r = -0.91, P less than 0.01). Abdominal discomfort caused termination in three of six PYR experiments but in none of the control experiments (mean exposure time 142 min). During immersion, metabolic rate, ventilatory volume, and respiratory rate increased significantly (P less than 0.05) over preimmersion levels and metabolic rate increased with duration of immersion (P less than 0.01) in both treatment but did not differ between conditions. PYR had no significant effect on rectal temperature, mean body temperature, thermal sensations, heart rate, plasma cortisol, or change in plasma volume. It was concluded that a 30-mg dose of PYR does not increase an individual's susceptibility to hypothermia during cold water immersion; however, in combination with cold stress, PYR may result in marked abdominal cramping and limit cold tolerance.     

钙对不同成熟期番茄果实的PG活性及其合成的影响

本文研究了钙处理不同成熟期番茄果实对果壁组织中钙含量与转化、多聚半乳糖醛酸酶(PG)活性与 PG 合成的影响。结果表明,钙处理绿熟期的番茄果实可使总钙和可溶性钙含量明显增加,并较多转化为结合钙;后期处理,进入和转化的钙都减少。同样,钙处理愈早,对果实 PG 活性的抑制愈强,绿熟期处理可完全抑制 PG 活性。凝胶电泳结合钌红染色,证明绿熟期果实无 PG,PG 是在果实成熟过程中新合成的。钙处理愈早,对 PG 合成的抑制愈强,绿熟期钙处理可完全抑制 PG 合成。     

余甘子采后软腐病拮抗菌的筛选、鉴定及其防效

【背景】由青霉菌引起的软腐病是余甘子采后贮藏期的主要病害,造成了经济损失严重。【目的】筛选对余甘子软腐病菌具有良好拮抗效果的放线菌菌株,并初步评价拮抗菌无菌发酵液的防治效果。【方法】以PenicilliumchoerospondiatisDQ23为指示菌,采用琼脂块法结合生长速率法进行拮抗菌株的筛选,并采用形态学特征、生理生化特性结合16S rRNA基因序列进行分类鉴定,并采用浸果法初步测定其无菌发酵液对余甘子软腐病发生及果实贮藏品质的影响。【结果】菌株SC-15对青霉P.choerospondiatis DQ23有较强的拮抗作用,拮抗圈直径为18.70 mm,20%无菌发酵液对软腐病菌的抑制率可达87.8%。根据菌株形态学和生理生化特性,结合16SrRNA基因序列分析将菌株SC-15鉴定为维及尼链霉菌(Streptomycesvirginae)。菌株SC-15无菌发酵液能降低余甘子的腐烂率和腐烂指数,延缓可溶性固形物和可滴定酸的降低,其中75%发酵液浸果效果最好,贮藏8d后,果实腐烂率为53.3%,果实腐烂指数为35.2%,可溶性固形物为4.8%,可滴定酸为6.25mg/g。【结论】菌株SC-15可有效防治余甘子采后青霉软腐病的发生,具有一定的应用价值。     

NPPB对低渗诱导海马神经元凋亡的拮抗作用

目的观察体积调节性氯离子通道阻滞剂NPPB对低渗条件下神经元凋亡的影响。方法采用原代培养的大鼠海马神经元细胞,实验分为对照组(无低渗溶液处理)、低渗组、低渗加NPPB干预组;在不同时间点(10min、30min、60min),应用AnnexinⅤ/PI流式细胞检测以及免疫细胞荧光三标法(TUNEL/MAP-2/DAPI)检测各实验组神经元凋亡的情况。结果与对照组相比,神经元在低渗干预10min后凋亡细胞明显增多,60min时神经元的凋亡达到高峰(P0.01),而NPPB干预组在各时间点凋亡神经元相对低渗组明显下降(P0.01),较正常对照组增高。结论低渗条件可诱导体外培养海马神经元细胞凋亡,体积调节性氯离子通道阻滞剂NPPB可以显著降低低渗诱导的神经元凋亡,提示VRAC通道参与了低渗诱导的神经元凋亡。     

Evaluation of Aspergillus aculeatus GC-09 for the biological control of citrus blue mold caused by Penicillium italicum

Blue mold caused by Penicillium italicum is a severe postharvest disease in citrus fruits. In this study, the fermentation product (FP-E) of Aspergillus aculeatus GC-09, an endophytic fungus isolated from a citrus plant, was found to exhibit antifungal activity against P. italicum with a MIC of 0.3125 mg/mL. The fungus A. aculeatus GC-09 was identified based on the studies of morphology and ITS nucleotide sequence. FP-E significantly inhibited the spore germination and mycelial growth of P. italicum. Scanning electron microscopy (SEM) results of P. italicum treated with FP-E showed shrunken, distorted and collapsed hyphae and conidiospores, indicative of the cell membrane damage, which was further confirmed by the propidium iodide (PI) fluorescent staining analysis. Consistent with the microscopy observation, FP-E led to the leakage of cellular constituents from P. italicum, which is evident from the increase in electrical conductivity and nucleic acid contents in the mycelial solution incubated with FP-E. In addition, FP-E treatment considerably increased the intracellular reactive oxygen species (ROS) content, and reduced the enzyme activities of both catalase (CAT) and peroxidase (POD) in P. italicum cells. Furthermore, orange fruits treated with FP-E showed fewer disease symptoms compared to the untreated fruits. These results suggested that the antifungal activity of FP-E might be associated with the disruption of cell membrane integrity, the accumulation of ROS level, and the reduction of the antioxidant enzymes activity of P. italicum. Therefore, A. aculeatus GC-09 might be a potential microbial resource for the biocontrol of citrus postharvest blue mold.     

Effects of pyridostigmine on ability of rats to work in the heat

Adult, male rats (300-325 g) were treated with pyridostigmine bromide (n = 22) or saline (n = 22) to quantitate the effects of cholinesterase inhibition (64%) on the ability to work (9.14 m/min, level treadmill) in the heat (35 degrees C). Pyridostigmine-treated rats had a mean endurance of 23 min, whereas saline-treated animals ran for nearly 35 min (P less than 0.001). Rates of rectal and skin temperature increments were significantly higher (P less than 0.001) in pyridostigmine-treated rats as were water losses (P less than 0.001). Exercise in the heat to hyperthermic exhaustion effected anticipated increments in circulating urea nitrogen, creatinine, lactate dehydrogenase, and potassium levels, whereas pyridostigmine pretreatment had additive effects on lactate and creatine kinase concentrations. Additionally, pyridostigmine elicited a significant (P less than 0.01) hyperglycemia before exercise, an effect noted also with other organophosphate simulants. We concluded that pyridostigmine-induced cholinesterase inhibition had a variety of debilitating effects during work in the heat.     

银杏内生细菌的分离鉴定及抑菌活性初探

【目的】从银杏(Ginkgo biloba)茎叶中分离鉴定内生细菌, 测定其体外抑菌活性及对辣椒果疫病的防治效果。【方法】采用平板对峙法筛选出对辣椒疫霉菌(Phytophthora capsici)有拮抗作用的内生细菌, 并用平板对扣法测定其中一株防治效果较好的内生细菌产生的挥发性物质对辣椒疫霉菌生长的影响。通过生防菌液和病原菌孢子悬浮液喷雾接种辣椒果测定该菌株对辣椒果疫病的防治效果。基于形态特征、生理生化特性、16S rDNA和gyrA基因序列同源性分析鉴定该生防菌株。【结果】从银杏的茎和叶中分离获得9株内生细菌。平板对峙生长试验结果表明, 菌株W5对供试的辣椒疫霉菌、稻瘟病菌(Pyricularia grisea)、水稻纹枯菌(Rhizoctonia solani)、黄瓜枯萎病菌(Fusarium oxysporum)、荔枝霜疫霉菌(Peronophythora litchi)、荔枝酸腐菌(Geotrichum candidum)均有抑制作用, 其中对辣椒疫霉菌、稻瘟病菌和荔枝霜疫霉菌的抑菌效果显著, 抑菌率分别为88.9%、86.3%和90.2%。其产生的挥发性物质能明显抑制辣椒疫霉菌菌丝的生长。对辣椒采后果疫病的防治效果表明, 先喷雾接种W5菌悬液24 h后再接种辣椒疫霉病菌孢子悬浮液的防治效果最好, 可将辣椒果的保鲜期延长2?3 d。该菌株被鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens)。【结论】获得了一株对植物病原菌物有良好防治效果的银杏内生解淀粉芽胞杆菌W5, 对辣椒采后果疫病及其他病原真菌的防治具有潜在应用价值。     

Systemic NO synthase inhibition blunts the chronotropic, but not the inotropic response to isoprenaline in man.

There is evidence that nitric oxide (NO) is involved in the chronotropic, the inotropic, and the vasodilator response to beta-adrenoceptor agonists. In the present study we hypothesized that inhibition of NO synthase may modulate the systemic vascular and cardiac effects of isoprenaline, a beta-adrenoceptor agonist, in healthy subjects. Subjects received stepwise increasing doses of isoprenaline (0.1-0.8 microg/min) in the absence or presence of systemic NO-synthase inhibition using two intravenous doses of N-monomethyl-L-arginine (L-NMMA; dosage 1, 3.0 mg/kg over 5 min, followed by 30 microg/kg/min over 75 min; dosage 2, 6.0 mg/kg over 5 min, followed by 60 microg/kg/min over 75 min) or peripheral vasoconstriction using exogenous endothelin-1 (ET-1; 5.0 ng/kg/min for 80 min). The chronotropic (RR interval) and the inotropic (QS2c) responses were assessed by noninvasive measurement of systolic time intervals. L-NMMA alone did not influence QS2c, but did increase the RR interval (P < 0.001) and the mean arterial blood pressure (P = 0.003). L-NMMA did not attenuate the blood pressure and the QS2c responses to isoprenaline, but significantly and dose-dependently blunted the heart rate response to beta-adrenoceptor stimulation (P = 0.029). ET-1 decreased the RR interval (P < 0.001) and increased the mean arterial blood pressure (P = 0.028). Our results indicate that beta-adrenoceptor mediated effects on the heart rate are much more susceptible to NOS inhibition than inotropic responses. This indicates that NO has an important role in heart rate control during beta-adrenoceptor stimulation.