ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018663

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018664

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

摘要:

SUMMARYThe cytogenetics of the macroconidium was studied in wild-type and mutant strains ofNannizzia gypseaandN. incurvata, the two perfect states ofMicrosporum gypseum.One mutant(ng)arose spontaneously inN. gypseaas a result of chromosomal aberration, and the other(ni)inN. incurvataas a single gene mutation. The developing macroconidium of the wild type passes through three developmental stages: The first is marked by active nuclear division in a swollen hyphal tip that grows into a macroconidium. The second stage is marked by vacuolation and redistribution of the nuclei, due to the enlargement of the macroconidium. The third is a stage of septation, further enlargement and thickening of the wall. In the mutantng, the macroconidium passes through the first stage with no noticeable variation. However, in the second and third stage variations occur. The nuclei are scattered and continue to divide, frequently forming chromatin threads, and septation often fails to occur or stops at the 2–3 septate condition. Occasionally, the macroconidia proliferate forming protuberances, long fine hyphae or secondary macroconidia. In the mutantni, the macroconidia are highly distorted and their development is too irregular to describe. The cytogenetics of these so-called“pleomorphic”mutants was compared with that of the M-type mutants inHypomyces solanif.Cucurbitae, the perfect state ofFusarium solani.In the latter organism the macroconidium arises as a single uninucleate cell in which each nuclear division is followed by a septum formation and the resultant cells are always uninucleate. It is concluded that, regardless of growth pattern and nuclear condition, the M-type mutants resemble closely the“pleomorphs,”and that mutation in the broad sense is the underlying mechanism of“pleomorphism”and the“dual phenomenon”in fungi. The last two terms, however, are inadequate and should be discarded.

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018665

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

摘要:

SUMMARYThe ultrastructural features of sporogenesis in the mucoraceous fungusGilbertella persicariaare illustrated and described, with emphasis on cytokinesis and spore wall formation. During cleavage, the principal structural changes involve pattern transformations of protoplasmic membranes. Endoplasmic reticulum (ER) is one of the most changeable membrane components, transforming from a complex fenestrated and branching form to a simpler sheet-like form during the course of cleavage.During precleavage, small vesicles are formed, apparently from special cisternae. The disappearance of these initial vesicles coincides with the appearance of cleavage vesicles. Cleavage vesicles are distinguished by the presence of granules on the inner surface of the vesicle membrane. Prior to cleavage, the nuclei, ER, and cleavage vesicles form an inter-associated system. Cleavage is initiated endogenously by the coalescence of cleavage vesicles to form a ramifying tubular cleavage apparatus. The cleavage apparatus demarcates the boundaries of potential spore initials. Lateral expansion of elements of the cleavage apparatus results in furrowlike configurations which converge to cut out spore initials as independent cells. The cleavage membrane is transformed to the plasma membrane of spore initials during late cleavage, at a time when the cleavage membrane and sporangial plasma membrane fuse. The columella is delimited by an apparatus that is structurally similar to the cleavage apparatus in the spore plasm. Columellar cleavage is completed when the spore plasm is at mid- cleavage.The marker granules that were present around the periphery of the cleavage vesicles are found on the outer surfaces of spore plasma membranes after cleavage. The granules fuse to form a continuous spore envelope, and subsequently the spore wall is laid down centripetally. Thus, the envelope becomes the outermost spore wall layer.

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018666

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

摘要:

SUMMARYThe thallus ofAmoebidium parasiticumis attached to its host animal by a basal, acellular holdfast. The holdfast is produced soon after sporangiospore release and may adhere, with varying effectiveness, to a variety of natural and unnatural substrates. Electron micrographs have disclosed a number of electron transparent pits which seem to perforate the cell wall at each end of the thallus. The holdfast material is always associated with one of these“pit fields”and it is assumed that the initial production and continued development of the holdfast occurs by extrusion of the adhesive through the terminal pit field. The cytoplasm adjacent to the holdfast contains a high density of membrane bound vesicles of approximately 0.24μin diam. The matrix of the vesicle resembles the amorphous holdfast material.

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018667

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

摘要:

SUMMARYThree new species of Myxomycetes collected from Kulu Hills in the northwestern Himalayas are described. They areLamproderma griseum, Diacheopsis depressa, andDidymium lenticulare.

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018668

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

摘要:

SUMMARYSix coprophilous discomycetes have been collected and described from Eastern Himalaya (India). They are:Cheilymenia coprinaria, C. theleboloides, C. stercorea, Ascobolus lignatilis, Thecotheus pelletieriand Ascophanus striatus.

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018669

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018670

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018671

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1968.12018672

出版商:Taylor&Francis    

年代:1968

数据来源: Taylor