Journal of Microbiology

Journal Article

Alteration in the ultrastructural morphology of mycelial hyphae and the dynamics of transcriptional activity of lytic enzyme genes during basidiomycete morphogenesis: Elena Vetchinkina , Maria Kupryashina , Vladimir Gorshkov , Marina Ageeva , Yuri Gogolev , Valentina Nikitina; J. Microbiol. 2017;55(4):280-288. Published online January 26, 2017; DOI: https://doi.org/10.1007/s12275-017-6320-z

Abstract: The morphogenesis of macromycetes is a complex multilevel process resulting in a set of molecular-genetic, physiological- biochemical, and morphological-ultrastructural changes in the cells. When the xylotrophic basidiomycetes Lentinus edodes, Grifola frondosa, and Ganoderma lucidum were grown on wood waste as the substrate, the ultrastructural morphology of the mycelial hyphal cell walls differed considerably between mycelium and morphostructures. As the macromycetes passed from vegetative to generative development, the expression of the tyr1, tyr2, chi1, chi2, exg1, exg2, and exg3 genes was acti-vated. These genes encode enzymes such as tyrosinase, chi-tinase, and glucanase, which play essential roles in cell wall growth and morphogenesis.

Review

MINIREVIEW] High-resolution imaging of the microbial cell surface: Ki Woo Kim; J. Microbiol. 2016;54(11):703-708. Published online October 29, 2016; DOI: https://doi.org/10.1007/s12275-016-6348-5

Abstract: Microorganisms, or microbes, can function as threatening pathogens that cause disease in humans, animals, and plants; however, they also act as litter decomposers in natural ecosystems. As the outermost barrier and interface with the environment, the microbial cell surface is crucial for cell-to-cell communication and is a potential target of chemotherapeutic agents. Surface ultrastructures of microbial cells have typically been observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Owing to its characteristics of low-temperature specimen preparation and superb resolution (down to 1 nm), cryo-field emission SEM has revealed paired rodlets, referred to as hydrophobins, on the cell walls of bacteria and fungi. Recent technological advances in AFM have enabled high-speed live cell imaging in liquid at the nanoscale level, leading to clear visualization of celldrug interactions. Platinum-carbon replicas from freeze-fractured fungal spores have been observed using transmission electron microscopy, revealing hydrophobins with varying dimensions. In addition, AFM has been used to resolve bacteriophages in their free state and during infection of bacterial cells. Various microscopy techniques with enhanced spatial resolution, imaging speed, and versatile specimen preparation are being used to document cellular structures and events, thus addressing unanswered biological questions.

Production of a monoclonal antibody and ultrastructure of the sporozoite of cryptosporidium parvum: Choi, Young Sook , Lee, Sung Tae , Cho, Myung Hwan; J. Microbiol. 1996;34(4):379-383.

Abstract: Cryptosporidium Parvum causes a life-threatening diarrhea in acquired immunodeficiency syndrome (AIDS) patients. The sporozoite stage of C. parvum has been known to be a target in treating cryptosporidiosis in AIDS patients as it is an extracellular stage. A sporozoite was ultrastructurally observed. It has a crescent shape with a rounded posterior end and a tapering body. The compact nucleus was located at the posterior end. A monoclonal antibody was produced, which recognized a 43 kDa of sporozoite antigens in a western blot analysis and showed the surface labeling in immunofluorescence.

Ultrastructure of the Cell Wall of a Null Pigmentation Mutant, npgA1, in Aspergillus nidulans: Yun Shin Chung , § , Jung-Mi Kim , Dong-Min Han , Keon-Sang Chae , Kwang-Yeop Jahng; J. Microbiol. 2003;41(3):224-231.

Abstract: The null pigmentation mutant (npgA1) of Aspergillus nidulans was previously characterized by its production of no pigment at any stage of its life cycle, its reduction in hyphal branching, and its delay in the asexual spore development. The chemical composition of the cell wall was also altered in npgA1 mutants that became more sensitive to Novozyme 234_TM, which is possibly due to a structural defect in the cell wall. To investigate the effects of the cell wall structure on these pleiomorphic phenomena, we examined the ultrastructure of the cell wall in the npgA1 mutant (WX17). Scanning electron micrographs (SEM) showed that after being cultured for six days, the outermost layer of the conidial wall of WX17 peeled off. Although this phenotype suggested that the cell wall structure in WX17 may be modified, examination using TEM of the fine structure of cross-sectioned hyphal wall of WX17 did not show any differences from that of FGSC4. However, staining for carbohydrates of wall layers showed that the electron-translucent layer of the cell wall was missing in WX17. In addition, the outermost layer H1 of the hyphal wall was also absent in WX17. The ultrastructural observation and cytochemical analysis of cell walls suggested that the pigmentation defect in WX17 may be attributed to the lack of a layer in the cell wall.

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