Attachment and adhesion of conidia of Stagonospora nodorum to natural and artificial surfaces

Attachment and adhesion of conidia of a wheat-isolate of Stagonospora nodorum to leaf and artificial surfaces was studied. Attachment of conidia was a non-viable process, separate from adhesion, that occurred rapidly and irreversibly. Attachment involved conidial-surface carbohydrates and was partially influenced by surface hydrophobicity. The subsequent adhesion, via the secretion of extracellular matrix from conidia, was a viable process that induced the complete cover of conidia in response to wheat leaf surface components containing epi-cuticular wax and to a lesser extent to barley but inducing only partial covering on glass. Results suggest that specific surface components from the compatible host promote rapid attachment and adhesion of S. nodorum conidia.     

Parasitism of <Emphasis Type="Italic">Trichoderma</Emphasis> on <Emphasis Type="Italic">Meloidogyne javanica</Emphasis> and role of the gelatinous matrix

Trichoderma (T. asperellum-203, 44 and GH11; T. atroviride-IMI 206040 and T. harzianum-248) parasitism on Meloidogyne javanica life stages was examined in vitro. Conidium attachment and parasitism differed beween the fungi. Egg masses, their derived eggs and second-stage juveniles (J2) were parasitized by Trichoderma asperellum-203, 44, and T. atroviride following conidium attachment. Trichoderma asperellum-GH11 attached to the nematodes but exhibited reduced penetration, whereas growth of T. harzianum-248 attached to egg masses was inhibited. Only a few conidia of the different fungi were attached to eggs and J2s without gelatinous matrix; the eggs were penetrated and parasitized by few hyphae, while J2s were rarely parasitized by the fungi. The gelatinous matrix specifically induced J2 immobilization by T. asperellum-203, 44 and T. atroviride metabolites that immobilized the J2s. A constitutive-GFP-expressing T. asperellum-203 construct was used to visualize fungal penetration of the nematodes. Scanning electron microscopy revealed the formation of coiling and appressorium-like structures upon attachment and parasitism by T. asperellum-203 and T. atroviride. Gelatinous matrix agglutinated T. asperellum-203 and T. atroviride conidia, a process that was Ca²⁺-dependent. Conidium agglutination was inhibited by carbohydrates, including fucose, as was conidium attachment to the nematodes. All but T. harzianum could grow on the gelatinous matrix, which enhanced conidium germination. A biomimetic system based on gelatinous-matrix-coated nylon fibers demonstrated the role of the matrix in parasitism: T. asperellum-203 and T. atroviride conidia attached specifically to the gelatinous-matrix-coated fibers and parasitic growth patterns, such as coiling, branching and appressoria-like structures, were induced in both fungi, similarly to those observed during nematode parasitism. All Trichoderma isolates exhibited nematode biocontrol activity in pot experiments with tomato plants. Parasitic interactions were demonstrated in planta: females and egg masses dissected from tomato roots grown in T. asperellum-203-treated soil were examined and found to be parasitized by the fungus. This study demonstrates biocontrol activities of Trichoderma isolates and their parasitic capabilities on M. javanica, elucidating the importance of the gelatinous matrix in the fungal parasitism.     

城市社区第五立面景观设计——从社会层面探讨城市社区景观

本文从城市社区景观规划与可持续社区建设的观念入手,在深入研究社区社会属性的基础上,充分发掘社区第五立面景观的概念、体系以及社会功能,并结合实例,初步得出社区第五立面景观的设计方法。     

根际微生物附着大豆根表影响因素的研究

在实验室条件下,研究了pH、温度、盐浓度和接种量4个因素对根际微生物(RM)附着大豆根表的影响。结果表明:不同pH、温度和NaCl浓度对根际微生物附着大豆根表有一定的影响,分别在pH 7～8、24～33℃和NaCl 30～60 mmol.L-1时RM附着量达到最佳,最大值出现在pH 7.5、30℃和NaCl 50或60 mmol.L-1,RM附着量与接菌量之间的线性回归方程为y=1.0021x+0.2982,相关系数R2=0.9925,表明RM的附着量与菌的接种量之间呈显著正相关。     

葡萄果实结构与耐贮性关系的研究

通过对巨峰、红地球、秋红、秋黑四个品种葡萄果实结构与耐压力、耐拉力关系的研究,发现葡萄浆果耐拉力大小与果柄粗细、果蒂大小以及果刷面积成正相关,与单位面积果柄和果蒂上所承受的浆果自重成负相关,耐压力强弱不仅受果肉质地影响,还与果粒大小有一定关系,与果皮厚度关系不大。果梗发育程度对葡萄耐贮性的影响远远大于果梗占果穗的比重,耐压力与耐拉力之间无明显关系。     

葡萄果实结构与耐贮性关系的研究

通过对巨峰、红地球、秋红、秋黑四个品种葡萄果实结构与耐压力、耐拉力关系的研究,发现葡萄浆果耐拉力大小与果柄粗细、果蒂大小以及果刷面积成正相关,与单位面积果柄和果蒂上所承受的浆果自重成负相关,耐压力强弱不仅受果肉质地影响,还与果粒大小有一定关系,与果皮厚度关系不大。果梗发育程度对葡萄耐贮性的影响远远大于果梗占果穗的比重,耐压力与耐拉力之间无明显关系。     

韩国大田市邻里公园不同年龄阶段游客的行为分析

为了解韩国邻里公园使用及游客特点,2013—2014 年通过对韩国大田广域市6 个邻里公园的1180 名游客的群体特征和行为现场观察与记录,并对游客的性别、年龄阶段、群体类型、身体姿势、活动行为、空间类型等6 个指标的频率进行χ2检验等分析。结果表明,对于游客不同年龄阶段和不同空间类型而言,游客的身体姿势都表现出相同的趋势,主要是移动、坐、站立3种。游客行为类别主要有7个类别,散步频率最高,为0.33;设施健身、观望、聊天、设施娱乐、野餐、打门球等6 个类别频率中等,在0.05 至0.1之间。游客使用空间频率较高的是林地和广场。在开放空间中要创造更多的人性空间满足人群不同活动行为需求。由于邻里公园存在空间单调问题,为了满足老年人和儿童、少年在热闹场所活动行为需要,建议在林地空间和活动空间边缘增加疏林空间。在邻里公园游客中,频率最多的是中年和老年,为0.31和0.28;频率中等的是儿童、青年,都约为0.18;频率最少的是少年,仅为0.06,因此建议为少年适当增加活动空间。如何创造包容性空间和依念场所是今后邻里公园建设和更新中值得重视的问题。     

Inhibition of viral adsorption and penetration by an aqueous extract from Rhododendron ferrugineum L. as antiviral principle against herpes simplex virus type-1

The polyphenol-enriched aqueous extract RF from the aerial parts of Rhododendron ferrugineum exhibited strong antiviral activity against herpes simplex virus type-1 while adenovirus 3 was not affected. RF exhibited an IC₅₀ of 7.4 μg/mL and a selectivity index of 64 when added to the virus inoculum prior to infection. RF abolished virus entry into the host cell by blocking attachment to the cell surface. When added after attachment at a concentration of > 25 μg/mL, RF inhibited also penetration of HSV-1 into the host cell. RF directly interacts with viral envelope proteins as demonstrated for the viral glycoprotein gD.     

法庭物证不同附着物上土壤的取样方法及源指示研究

土壤由于其广泛性和易于附着性等特点,在法庭物证溯源比对方面发挥着一定作用。为明确不同附着物取样方法对土壤性质的影响以及附着物上土壤的源指示作用,本研究选择在城市–城郊进行路线模拟,采集不同路段、不同环境条件下的原土,并对每个采样点进行纤维类(手套)、金属类(铁锹)和橡胶类(鞋底)附着土壤模拟。对不同附着物分别采用了干刷和水洗/滴洗两种方法进行取样,使用便携式X射线荧光光谱仪(XRF)测定土壤样品。结果表明,取样方法对纤维类和橡胶类附着土壤样品的元素含量无显著影响,但干刷法操作更方便快捷;金属类附着土壤的滴洗法优于干刷法。依据土壤元素含量和主成分分析,纤维类和金属类附着的土壤可以与其来源具有较好匹配效果;由于鞋子(橡胶类)经过较长的路线后,鞋底附着的土壤反映经过路线的综合信息,其更多情况下鞋底样品与最后经过的土壤源更相近,主成分分析结合欧氏距离对鞋底土壤源指示起到一定作用。因此,纤维类、金属类和橡胶类附着物可为未知土壤样品来源推断提供依据,对于土壤源指示有一定帮助,但实际应用中需要采用多种分析方法结合环境信息进行综合判断。本次模拟试验可为不同附着物取样方法得到的土壤样品的比对和源指示提供...     

Morphological studies on attachment of spores of <Emphasis Type="Italic">Magnaporthe grisea</Emphasis> to the leaf surface of rice

Rice leaves were inoculated with spores of Magnaporthe grisea, and the number of fluorescence-labeled spores that attached to the leaf surface were counted before and after leaves were dipped and then stirred in water. Just 5% of the spores were retained on the leaf surface 1h after inoculation; the percentage retained then increased rapidly between 1.25 and 1.50h, and most had attached by 2h. Scanning electron microscopy revealed that most conidia were lying on a few wart-like protuberances 2–4µm high. Spores became attached when the germ tubes were long enough to reach the leaf surface, at least 3µm, by mucilaginous substances at the tip. Retained spores swayed when water was added under the cover glass from one side, indicating that the attachment was confined to the tips of germ tubes. Spores are attached to the rough leaf surface by mucilaginous substances – not at the tip of spore as reported on smooth artificial substrates but at the tip of the germ tubes.