林生地霉血液分离株的形态学观察

Observation on the morphology of one Geotrichum silvicola isolated from a patient's blood

目的 进一步了解林生地霉的形态学特征和产孢方式。方法受试菌株复苏后，转种于沙堡培养基，37℃和27℃温箱培养3周，每天观察菌落生长情况，并对其丝状型和酵母样型两种菌落进行光镜观察。在培养1周时，挑取菌落常规制片后行扫描电镜和透射电镜观察。结果 培养第2～3d，菌落开始生长，初为白色绒毛样、粉末样，1～2周后菌落均转变为乳酪样，其中37℃下培养的菌落转变较早。菌丝相时，光镜下可见丰富的分支、分隔菌丝，成链的关节孢子和圆形、椭圆形小分生孢子。酵母相时，光镜下可见丰富的芽生孢子，少量的厚膜孢子、外生或内生的关节孢子，菌丝稀少。扫描电镜下可见菌丝分支末端或侧面着生球形、棒状的分生孢子，末端凹陷。透射电镜下可见分生孢子与菌丝分离时全壁断裂，另一端正在出芽。结论 林生地霉包括丝状型和酵母样型两种菌落形态和链状排列的矩形关节孢子、圆形或椭圆形的小分生孢子、厚膜孢子以及分支、分隔菌丝为其形态学特征，有芽殖、外生和内生节孢子三种产孢类型。

Objective To observe the morphologic characteristics and conidiogenesis of Geotrichum Silvicola. Methods The fungus was inoculated into the sabouraud＇s agar and cultured under 37℃ and 27℃ for 3 weeks. We observed the development of colonis every day and the type of mycelium and yeast was examined under light microscope every day. The sample after 1 week were examined through scanning electron microscope and transmission electron microscope respectivily. Results When cultured for 2 - 3 days,they Geotrichum Silvicola began to grow and turned to be whitish,wooly or powder-like at first few days and butyrous in 1 to 2 weeks. Colonis cultured under 37℃ were transformed into yeast-like ones earlier than under 27℃. Under light microscope,it showed abundant branched hyphae with septa,chained arthroconidia, round or oval microspores in the type of mycelium and abundant bud- ding spores,a few chlamydospores and holoarthric or enteroarthric conidia,few haphae in the type of yeast. Under scanning electron microscopy,it showed spherical or clavate conidium,pitted in ends,were formed laterally or in the end of branched haphae. When seperated,the haphae were left with fiat scars. Under transmission electron microscope, it showed that the whole wall was boken when conidia seperated from haphae and in the other end of conidia one bud was being formed. Conclusions The type of mycelium and yeast-like colony,and, chained arthroconidium, ellipsodial or round microspores,chlamydospores,branched haphae are the characteristics of morphology of Geotrichum silvicola. Budding, holoarthric and enteroarthric conidia were three types of conidiogenesis of Geotrichum silvicola.