Cytochemical Investigation of the Antagonistic Interaction Between a Microsphaeropsis sp. (Isolate P130A) and Venturia inaequalis

ABSTRACT In an attempt to better understand the mode of action of the antagonistic fungus Microsphaeropsis sp., the interaction between this fungus and Venturia inaequalis was studied, using both light and electron microscopy. Cytological observations indicated that the antagonistic interaction between the two fungi likely involves a sequence of events, including (i) attachment and local penetration of Microsphaeropsis sp. into V. inaequalis hyphae; (ii) induction of host structural response at sites of potential antagonist entry; (iii) alteration of host cytoplasm; and (iv) active multiplication of antagonistic cells in pathogen hyphae, leading to host cell breakdown and release of the antagonist. The interaction was investigated further by gold cytochemistry. The use of gold-complexed beta-1,4-exoglucanase and wheat germ agglutinin/ovomucoid-gold complex to localize cellulosic beta-1,4-glucans and chitin monomers, respectively, resulted in regular labeling of V. inaequalis cell walls. This finding supports other studies refuting the classification of ascomycetes as only a glucan-chitin group. At an advanced state of parasitism, the labeling pattern of cellulose and chitin, which clearly showed that the level of integrity of these compounds was affected, suggested the production of cellulolytic and chitinolytic enzymes by Microsphaeropsis sp. Wall appositions formed in V. inaequalis in response to the antagonist's attack contained both cellulose and chitin. However, penetration of this newly formed material frequently succeeded. This study provides the first detailed picture of the cytological events associated with mycoparasitism in V. inaequalis.     

高CO2/低O2气调贮藏对2个甜樱桃品种采后香气组分的影响

采用项空固相微萃取和气相色谱质谱联用技术分析了2个甜樱桃品种‘Kordia’和‘Vanda’在不同气调贮藏条件下果实香气成分的差异.结果表明,醇类、酯类、萜类和醛类是Kordia和Vanda的主要香气组分,其中15种醇类(主要成分有乙醇、2E-己烯醇和戊醇)占芳香物质总量的39％,8种酯类(主要成分有2E-己烯醇乙酸酯和戊酸丁酯)占测定芳香物质总量的39％,4种萜类(主要成分有柠檬烯和α--芳樟醇)占测定芳香物质总量的15％,10种醛类(主要成分有2E-己烯醛和2E-辛烯醛α--芳樟醇)占测定芳香物质总量的7％.其中戊醇、2E-己烯醛、2E-辛烯醛、戊酸丁酯、2E-己烯乙酸酯和柠檬烯等6种成分总含量占测定芳香物质总量的80％以上,3种气调贮藏条件下54 d后,樱桃果梗仍然为绿色,有10％的樱桃果梗逐渐变干,常规气调贮藏条件下樱桃果梗变为褐色.两者存在显著差异.     

新鲜猪肉的品质与稳定性

猪应激综合征(PSS)与经济效益有密切的关系。易发生 PSS 的猪对环境刺激很敏感,表现出一系列临床症状,严重时发高烧或死亡。应激时猪的神经、内分泌、循环、肌肉等发生结构和代谢方面的变化。应激敏感猪的肌肉发达,并具有一种特殊的基因(氟烷基因),易产生 PSE(仓白、松软、渗出性)猪肉。     

菌索接种蜜环菌的简易技术

一、前言受蜜环菌感染的木材是最常用的接种体尽管用这种方法能够较好地摸拟接种感染,但由于不可能预测到根和菌索的接触部位和菌索的脆碎期,所以菌索侵染的发生无规律可循,而且菌索与根的接触的检测很花费时间。因此侵染早期阶段的调查研究尤为复杂。所以,通过对天然感染根的观察,得到了直接用菌索作为接种体的方法便克服了这些障碍。     

苏铁坏死矮化病毒

苏铁坏死矮化病毒黄法余（广东南海动植物检疫局５２８２００）苏铁Ｃｙｃａｓｒｅｖｏｌｕｔａ是一种热带和亚热带广泛种植的园林植物。我国近几年从日本、泰国、南朝鲜、台湾等国和地区大量进口苏铁种子和种苗。苏铁坏死矮化病毒（Ｃｙｃａｓｎｅｃｒｏｔｉｃｓｔｕｎｔ...