Spores development

Endospore An asexual spore developed within the cell. 

TeuosporE One of the thick walled chlamydospores or winter spores, developed in the life cycle in rust fungi. 

Response to a biocide depends upon the cellular stage of development. Sporulation, a process in which a bacterial spore develops from a vegetative cell, involves seven stages (I—VII Chapter 3) of these, stages IV-VII (cortex and coat development) are the most important in relation to the development of biocide resistance. Resistance to biocidal agents develops during sporulation and may be an early, intermediate or late/very late event. For example, resistance to chlorhexidine occurs at an intermediate stage, at about the same time as heat... 

Aspergillus nidulans uses a family of oxygenated long-chain fatty acids called psi factor (precocious sexual inducer), such as psiBa (8-hydroxy-18 2-9,12) and psiCa (5,8-dihydroxy-18 2-9,12) to modulate sexual and asexual spore development. Both hydroxyl fatty acids are produced by cytochrome P450-like fatty acid oxygenases using linoleic acid as a substrate (Tsitsigiannis et al. 2005). 

Fig. 3. Uranium activity concentrations in hyphae and spores developing in the hyphal compartment (top) and in the mycorrhizal roots (bottom) developing in the central root compartment for Ri T-DNA transformed carrot (Daucus carota L.) roots grown in association with G. intraradices in a two-compartment system with 0.1 p,M added to the hyphal compartment set at pH 4, 5.5 and 8. Data used with permission from Rufyikiri et al. (2002).

Three techniques have proved particularly useful in studying the resistance of spores to aldehydes (a) the removal of outer spore layers by chemical means [217], (b) the use of mutants of B. subtilis 168 which cannot proceed beyond defined points in spore development [248], and (c) a step-down procedure in which vegetative cells growing in a rich medium are transferred into a nutritionally poor medium, when 90% synchronous sporulation is achieved during subsequent incubation [249]. Coat removal methods utilizing urea plus dithiothreitol with or without sodium lauryl sulphate at alkaline pH are known to remove a significant amount of the spore cortex too [249], with the subsequent addition of lysozyme enhancing this effect [53]. 

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