Fine structure of sporangiole development in Choanephora cucurbitarum (Mucorales)

1982 ◽  
Vol 60 (11) ◽  
pp. 2313-2324 ◽  
Author(s):  
Michael T. Higham ◽  
Kathleen M. Cole
Keyword(s):  
Electron Microscopy ◽  
Germ Tube ◽  
Tube Wall ◽  
Outer Wall ◽  
Spore Wall ◽  
Wall Layer ◽  
Choanephora Cucurbitarum ◽  
Dark Staining ◽  
Granular Vesicles ◽  
Scanning Electron

Spore development was studied in Choanephora cucurbitarum by using transmission and scanning electron microscopy. Sporangioles are produced by expansion of the ampulla wall. A two-layered spore wall is then constructed within the spine-covered sporangiole wall. The outer spore wall layer is longitudinally grooved and is devoid of spines or appendages. The inner wall layer is thinner and electron transparent. During wall production, dark-staining granular vesicles were observed in the spore cytoplasm. Their contents stained similarly to the material of the outer wall layer. Mature spores possessed a third, innermost wall layer. This was identified as a new wall layer, which was continuous with the germ-tube wall of germinated spores. Released spores were observed to be contained within the sporangiole during dispersal and germination.

Ultrastructural studies on germinating ascospores of Daldinia concentrica

1976 ◽  
Vol 54 (8) ◽  
pp. 698-705 ◽  
Author(s):  
A. Beckett
Keyword(s):  
Electron Microscope ◽  
Germ Tube ◽  
Tube Wall ◽  
Spore Wall ◽  
Wall Layer ◽  
Ultrastructural Studies ◽  
Early Stages ◽  
Ascospore Germination ◽  
Daldinia Concentrica

Ascospore germination in Daldinia concentrica has been studied using light and electron microscope techniques. Preliminary observations indicated that lipid globules were utilized during early stages of germination. Apical wall vesicles were localized during germ tube initiation and were involved in the differentiation of a filamentous germ tube. Wall synthesis occurred during germination and resulted in a new wall layer, which was different in ultratexture to the spore wall and which formed the germ tube wall. Possible implications of the concept of spore wall and vegetative wall types during germination are discussed.

Ultrastructure of the dormant and germinating sporangiospore of Phascolomyces articulosus (Mucorales)

1978 ◽  
Vol 56 (7) ◽  
pp. 747-753 ◽  
Author(s):  
P. Jeffries ◽  
T. W. K. Young
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Freeze Fracture ◽  
Spore Wall ◽  
Wall Layer ◽  
Thin Sections ◽  
Transmission Electron ◽  
Sporangial Wall ◽  
Scanning Electron

Using results obtained with light and scanning electron microscopy of critical-point-dried material and transmission electron microscopy of carbon replicas and freeze-fracture and ultra-thin sections, the structure and germination of the sporangiospore of Phascolomyces articulosus Boedijn is described. The sporangial wall is trilaminate and the ornamented spore wall is two layered. During germination, a new wall layer develops between the plasmalemma and the original spore wall. Sporangial structure is related to that of other members of the Thamnidiaceae and the use of germinating spores of P. articulosus for infection studies of the mycoparasite Piptocephalis unispora is indicated.

scholarly journals Parasitism of spores of the vesicular-arbuscular mycorrhizal fungus, Glomus dimorphicum

2005 ◽  
Vol 72 (1) ◽  
pp. 27-32 ◽  
Author(s):  
S.M. Boyetchko ◽  
J.P. Tewari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Host Response ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Spore Wall ◽  
Vesicular Arbuscular ◽  
Scanning Electron

Spores of Glomus dimorphicum were examined for parasitism. Light and scanning electron microscopy revealed perforations, approximately 0.25 to 1.0 µm in diameter, in the spore wall. The presence of papillae, a dynamic host response, suggested that the parasitism occurred while the vesicular-arbuscular mycorrhizal fungus was still alive. No filamentous structures were detected in the spores; however, cysts of amoeba-like organisms were found in the spores and were also observed on agar plates on which surface-sterilized spores of G. dimorphicum containing such organisms were placed. It is postulated that an amoeba-like organism was the parasite, since the perforations on the spore wall were minute and no bacteria or fungi were seen inside the spores.

Ascospore germination, growth in culture, and imperfect spore formation in Cookeina sulcipes and Phillipsia crispata

1975 ◽  
Vol 53 (1) ◽  
pp. 56-61 ◽  
Author(s):  
J. W. Paden
Keyword(s):  
Germ Tube ◽  
Outer Wall ◽  
Wall Layer ◽  
Spore Formation ◽  
Spore Surface ◽  
No Formation ◽  
Ascospore Germination ◽  
Germ Tubes

Ascospores of Cookeina sulcipes germinate by one of two modes: (1) by the production of blastoconidia on sympodially proliferating conidiogenous cells which may arise from any point on the spore surface, and (2) by a thick polar germ tube. No ascospores were seen to germinate both ways. The conidiogenous cells are occasionally modified into narrow hyphae. The blastoconidia germinate readily but are evidently very short-lived. Ascospores of Phillipsia crispata germinate by two polar germ tubes; there is no formation of blastoconidia. In both species the inner ascospore wall separated from an outer wall layer during germination. In culture both C. sulcipes and P. crispata form arthroconidia. The arthroconidia are uninucleate; they germinate readily and reproduce the species when transferred to fresh plates.

Ultrastructural development of merosporangia in the mycoparasite Piptocephalis indica

1979 ◽  
Vol 57 (21) ◽  
pp. 2460-2465 ◽  
Author(s):  
Karen K. Baker
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wall Layer ◽  
Outer Electron ◽  
Early Cleavage ◽  
Single Row ◽  
Transparent Wall ◽  
Cleavage Stages ◽  
Scanning Electron

Transmission and scanning electron microscopy were used to study the ultrastructural development of merosporangia of Piptocephalis indica. Merosporangial branches were initiated from heart-shaped basal-spore initials on dichotomously branched sporangiophores. After elongation, spores were cleaved out of the merosporangial protoplast by simultaneous invagination of the plasmalemma. The plasmalemmal invaginations fused at the center of the merosporangium and delimited a varying number of more or less equal-sized spores in a single row. At maturity. spores had an inner, electron-transparent wall layer and an outer, electron-opaque wall layer. Mature spores possessed scars at each end with the basal spore having scars at each point of merosporangial disarticulation. Fertile branches were highly vacuolated at the time of spore detachment. Development of merosporangiospores in P. indica is similar to that in Syncephalis sphaerica at the early cleavage stages with some differences evident at postcleavage.

Optimization of the Antimicrobial Effects of Surfactin against Bacillus cereus Spores

2020 ◽  
Vol 83 (11) ◽  
pp. 1983-1988
Author(s):  
XIANQING HUANG ◽  
LIANJUN SONG ◽  
MINGWU QIAO ◽  
PINGAN ZHANG ◽  
QIUYAN ZHAO
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacillus Cereus ◽  
Control Sample ◽  
Outer Wall ◽  
Experimental Results ◽  
Optimal Conditions ◽  
Design Expert ◽  
Temperature Time ◽  
Scanning Electron

ABSTRACT The purpose of this study was to establish a three-variable bactericidal model of temperature, time, and concentration to determine the optimal conditions for Bacillus cereus spore inactivation by surfactin. To obtain the binary regression equation of the inactivated spore model, a total of 17 simulations were performed using response surface methodology. The experimental results showed that the three factors each had a discernible but nonequal impact on the inactivation response value. Multiple regression analysis of experimental results using Design-Expert software yielded the following equation: Y = 1.47 + 0.39ξ1(temperature) + 0.38ξ2(time) + 0.39ξ3(concentration) − 0.20ξ1ξ2 + 0.22ξ1ξ2 − 0.12ξ2ξ3 − 0.23ξ12 − 0.11ξ22 − 0.40ξ32. Optimal inactivation of spores was achieved by treatment with surfactin at a concentration of 4 mg/mL for 40 h at 53°C, with the response value reaching 1.8. The spores were treated with surfactin under these conditions; the microstructural changes of spores were observed by use of scanning electron microscopy. We found that the structures of the outer wall of the spores were damaged, whereas the spores in the control sample showed no visible damage. HIGHLIGHTS

Morphogenesis of arthroconidiation in the dermatophyte Trichophyton mentagrophytes with special reference to wall ontogeny

1984 ◽  
Vol 30 (11) ◽  
pp. 1415-1421 ◽  
Author(s):  
Tadayo Hashimoto ◽  
R. G. Emyanitoff ◽  
R. C. Mock ◽  
J. H. Pollack
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Trichophyton Mentagrophytes ◽  
Outer Wall ◽  
Time Lapse ◽  
Wall Layer ◽  
Spore Surface ◽  
Inner Surface ◽  
Initial Sign ◽  
Hyphal Wall

The formation of arthroconidia, especially the ontogeny of the arthroconidial wall in the dermatophyte Trichophyton mentagrophytes, was investigated by light and electron microscopy. Time-lapse photomicroscopy revealed that the new septa were inserted regularly along the length of the hypha. Each new septum divided a preexisting hyphal segment into approximately equal halves. The initial sign of arthroconidium formation detected by electron microscopy was the deposition of a conidium-specific wall layer on the inner surface of the preexisting hyphal wall. The invaginating septal material was continuous with the newly deposited inner wall layer of the sporulating hyphae. When septation was completed, the septum and septal furrow were continuous across the wall to the inner edge of the outer wall layer. After septation, the inner wall continued to thicken until it attained the thickness of a mature arthroconidial wall (0.3 – 0.5 μm). Simultaneously, immature arthroconidia continued to swell and eventually assumed a barrel shape. When disarticulated, arthroconidia were surrounded by the newly formed conidial wall at the poles, and the sides of the conidia were additionally bounded by the residual hyphal wall. As the arthroconidia matured, the remnants of the hyphal wall tended to be detached from the spore surface. From these observations we conclude that T. mentagrophytes formed arthroconidia by the enteroarthric mode rather than the holoarthric process as previously described.

Investigations of Entomophthora muscae (Cohn) (Entomophthorales: Entomophthoraceae) conidial infection on housefly Musca domestica (Linn.) by scanning electron microscopy

1993 ◽  
Vol 39 (4) ◽  
pp. 363-366
Author(s):  
C. M. Tu ◽  
B. L. Singh
Keyword(s):  
Electron Microscopy ◽  
Germ Tube ◽  
Tube Formation ◽  
Insect Cuticle ◽  
Entomophthora Muscae ◽  
Entomogenous Fungus ◽  
Insect Pathology ◽  
Germ Tubes ◽  
Infection Cushion ◽  
Scanning Electron

An entomogenous fungus, Entomophthora muscae, was studied morphologically with respect to the formation of primary and secondary conidia and germ tubes. The fungus penetrated the insect cuticle by germ tubes that were produced at the base of each conidium that penetrated directly through the cuticle. Fungal germ-tube formation and penetration of host integument were observed. The tough germ-tube penetration point seemed to provide abundant energy for the penetration of the host integument. Conidia not directly on the integument formed secondary conidia but were never observed to form germ tubes. Neither appressorium nor infection cushion was observed on the germ tubes.Key words: Entomophthora muscae, entomogenous fungus, insect mycosis, insect pathology, conidia.

The fine structure of mature and germinating chlamydospores of Fusarium oxysporum

1979 ◽  
Vol 25 (7) ◽  
pp. 808-817 ◽  
Author(s):  
I. L. Stevenson ◽  
S. A. W. E. Becker
Keyword(s):  
Fusarium Oxysporum ◽  
Germ Tube ◽  
Spore Wall ◽  
Wall Layer ◽  
Close Apposition ◽  
Exterior Surface ◽  
Thin Sections ◽  
Subcellular Organelles ◽  
Innermost Layer ◽  
Rapid Appearance

A number of features not described previously has been revealed in electron-microscope studies of mature chlamydospores of Fusarium oxysporum. On the maturation of one isolate, many spores formed a thick matrix-like layer containing electron-dense particles on the exterior surface of the spore wall. In thin sections of mature chlamydospores of the same isolate, cisternae of endoplasmic reticulum surrounding, and in close apposition to, the limiting boundary of the lipid bodies were revealed.The germination of chlamydospores was accompanied by (a) the rapid appearance of polysaccharide deposits and changes in the configuration of some subcellular organelles, (b) the formation of a new wall layer between the plasma membrane and the innermost layer of the spore Wall, (c) the rupture of the outermost coats of the spore wall, and (d) the emergence of the germ tube as an extension of the new wall layer.

scholarly journals Leaflet Surfaces of Blackspot-resistant and Susceptible Roses and Their Reactions to Fungal Invasion

HortScience ◽  
1992 ◽  
Vol 27 (2) ◽  
pp. 133-135 ◽  
Author(s):  
S. Reddy ◽  
J.A. Spencer ◽  
S.E. Newman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Germ Tube ◽  
Fungal Development ◽  
Fungal Invasion ◽  
Diplocarpon Rosae ◽  
Surface Patterns ◽  
Rosa Roxburghii ◽  
Physical Features ◽  
Scanning Electron

Leaflet surfaces of two blackspot (Diplocarpon rosae Wolf)-resistant roses (Rosa roxburghii Tratt and R. wichuraiana Crep.) and two susceptible roses (R. hybrida `Electron' and `Pascali') were compared using scanning electron microscopy to determine whether physical features of the leaflet surface were associated with resistance to the fungal invasion. The leaflet surface features of the resistant roses were dissimilar: R. roxburghii leaflet surface had protruding cells and was densely covered with amorphous wax platelets, whereas R. wichuraiana surface was smooth with less distinct epidermal cells and sparsely distributed wax granules. Leaflet surface patterns of both susceptible roses, however, were similar. The spores of D. rosae failed to germinate on R. roxburghii and R. wichuraiana. In contrast, the spores on `Electron' and `Pascal? germinated, with the germ tube penetrating the cuticle. There were no apparent morphological barriers on leaflet surfaces of R. roxburghii and R. wichuraiana to explain the observed resistance to fungal development.

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