Observations of Microsporum canis with cryoscanning and scanning electron microscopy

The observations of Microsporum canis with cryoscanning and scanning electron microscopy without fixation and dehydration were reported. In the former an almost native state was observed through showing some fuzzy outlines due to frost; in the latter it was shown that marked shrinkage and distortion had occured. There were many granules on the surface of the macroconidia though their function is uncertain.     

Lipases of Fonsecaea pedrosoi and Phialophora verrucosa

Lipase activity was demonstrable titrimetrically in the culture filtrates of Fonsecaea pedrosoi and Phialophora verrucosa on the 6th day of incubation reaching a peak on the 15th and 12th days respectively for the two fungi. Purified lipases of F. pedrosoi and P. verrucosa, with specific activities of 36.0 and 39.4 fold increase respectively, were obtained by cold acetone extraction, gel filtration followed by ion exchange chromatography. The lipases had the same optimum pH (5.5) and temperature (35° C). The molecular weights of the lipases of F. pedrosoi and P. verrucosa, estimated by gel filtration on Sephadex G-100, were 25000 and 20000, respectively and the enzymes showed broad susbstrate specificity. The possible role of lipase in the pathogenesis of infection caused by the fungi is discussed.     

中国海区几种隐藻类鞭毛藻的扫描电镜观察

报道了来自香港吐露港、中国长江口及厦门港的3个属的3种隐藻及1个变种, 即半片藻Hemiselmis sp. Novarino、伸长斜片藻Plagioselmis prolonga Butcher ex Novarino, Lucas ＆ Morrall、伸长斜片藻北方变种Plagioselmis prolonga var. nordica Novarino, Lucas ＆ Morrall、尖尾全沟藻Teleaulax acuta （Butcher） Hill, 并对每个种类的分类特征、生态分布进行描述, 同时提供每个种的光镜和扫描电镜照片。其中, 半片藻属Hemiselmis Parke是中国海区首次记录的属, 而伸长斜片藻Plagioselmis prolonga和尖尾全沟藻Teleaulax acuta可以引发赤潮。     

井上蛀果斑螟触角感器的扫描电镜观察

利用扫描电镜对井上蛀果斑螟Assarainouei Yamanaka雌雄成虫触角及触角感器的超微结构、类型和分布进行详尽观察。结果表明,井上蛀果斑螟触角上主要分布有9种类型的感器,其中毛形感器2种,锥形感器、刺形感器、耳形感器、腔锥形感器、腔乳头状感器、鳞形感器及Bohm氏鬃毛均1种。其中的腔乳头状感器只在雌虫触角上有分布,雄虫触角鳞形感器及末端毛形感器的数量均多于雌虫。     

Granulomatous reactions induced by lipids extracted from Fonsecaea pedrosoi, Fonsecaea compactum, Cladosporium carrionii and Phialophora verrucosum

Granulomatous reactions induced by lipid extracts from the dermatophyte fungi Fonsecaea pedrosoi, Fonsecaea compactum, Cladosporium carrionii and Phialophora verrucosum, the causal organisms of chromoblastomycosis, were studied. Charcoal particles coated with the lipid extracts were prepared and injected intravenously into mice. Inflammation was characterized by an intense mononuclear cell infiltrate that lodged in the lung from 4 to 8 d after inoculation.     

Isolation of Phialophora verrucosa and Fonsecaea pedrosoi from nature in Japan

Seventeen strains of Phialophora verrucosa and one strain of Fonsecaea pedrosoi were isolated from natural sources such as rotting wood, pine bark, pine logs or soil in Japan. These saprophytic isolates were compared morphologically, biologically and serologically with human isolates and their virulence for rats was studied. There were no distinct differences between the isolates from the two sources.     

悬铃木方翅网蝽触角感器扫描电镜观察

利用扫描电镜对悬铃木方翅网蝽Corythucha ciliata(Say)雌、雄成虫触角背面和腹面进行观察。结果表明:悬铃木方翅网蝽触角为棒状,共4节,分为柄节、梗节和鞭节。触角上共有4种感器,分别为刺型感器、锥形感器、毛型感器和芽型感器;这些感器不存在性二型现象。其中,刺型感器分为大刺型感器和小刺型感器2种类型;芽型感器首次在异翅亚目昆虫触角上发现。雄成虫触角感器数量明显多于雌成虫,不同类型的感器在触角各节上的数量与分布各不相同。     

Observations on charging effects of non-conductive and uncoated materials by ion beam pre-bombardment in scanning electron microscopy

The specimen charging defects of non-conductive materials in scanning electron microscopy are discussed with reference to the surface electric field generated by the illuminating electron beam dose. If the charge density depends on the relaxation time constant as defined by a product of the permittivity and resistivity when known or available, the electric field can be evaluated by the incident dose stored when illuminated by an electron scanning beam.It was found by observation that uncoated or non-conductive materials pre-bombarded by a positive ion beam, which contributes to the generated negative field, together with the charging effects, could be eliminated at the optimum time of neutralization.In the normal process of double fixation and staining of biological specimens, the local electric field produces increased contrast due to polarization effects. The dark and bright images of secondary and backscattered electrons, respectively, can be analysed by taking into account local polarization, in addition to voltage contrast.     

Transmission electron microscopy of tissue prepared for scanning electron microscopy by ethanol-cryofracturing.

Tissue processed for scanning electron microscopy by ethanol-cryofracturing combined with critical point drying was embedded and sectioned for transmission electron microscopy. Study of specimens cut in a plane passing through the fracture edge indicated that preservation of cellular fine structure of fractured cells was excellent. Even at the most peripheral edge of the fracture there was no evidence that movement of cytoplasmic components occurred to distort the original structural organization of fractured cells. Lack of cytoplasmic detail in ethanol-cryofractographs has been due more to the nature of the fracturing of the tissue and to the obscuring effects of the metal coating than to structural deformation at the fracture edge or to limitations in resolving power of the scanning electron microscope used.     

Complementary visualization of mitotic barley chromatin by field-emission scanning electron microscopy and scanning force microscopy

The surface structure of mitotic barley chromatin was studied by field-emission scanning electron microscopy (FESEM) and scanning force microscopy (SFM). Different stages of the cell cycle were accessible after a cell suspension was dropped onto a glass surface, chemical fixed, and critically point dried. Imaging was carried out with metal-coated specimen or uncoated specimen (only for SFM). The spatial contour of the chromatin could be resolved by SFM correlating to FESEM data. The experimentally determined volume of the residue chromatin during mitosis was within the range of 65-85 microm(3). A comparison with the theoretically calculated volume indicated a contribution of about 40% of internal cavities. Decondensation of chromosomes by proteinase K led to a drastic decrease in the chromosome volume, and a 3-D netlike architecture of the residue nucleoprotein material, similar to that in the intact chromosome, was obvious. Incubation of metaphase chromosomes in citrate buffer permitted access to different levels of chromatin packing. We imaged intact chromosomes in liquid by SFM without any intermediate drying step. A granular surface was obvious but with an appreciably lower resolution. Under similar imaging conditions proteinase K-treated chromosomes exhibited low topographic contrast but were susceptible to plastic deformations.     

Natural populations of bacteria in Lake Kinneret: Observations with scanning electron and epifluorescence microscopy

The bacterioplankton assemblage in Lake Kinneret, Israel, sampled on 6 occasions representative of different seasonal conditions was studied with scanning electron microscopy (SEM) and epifluorescence microscopy after acridine-orange staining. In near-surface (1–3 m) samples taken in October 1981 and March 1983, several unusual types of budding, appendaged, and filamentous cells were found. During lake stratification, typical large anaerobic forms (including photosynthetic green sulphur bacteria) were observed in samples from the metalimnion and deep (40 m) hypolimnion. Epifluorescence counts indicated that bacteria in the water column ranged from 0.55 to 2.67 × 10⁶ cells ml^–1.