Étude en microscopie électronique de Conidiobolus obscurus. I. Formation et germination des azygospores

1982 ◽  
Vol 60 (4) ◽  
pp. 413-431 ◽  
Author(s):  
J. P. Latgé ◽  
M. C. Prévost ◽  
D. F. Perry ◽  
O. Reisinger
Keyword(s):  
Metabolic Pathways ◽  
Spore Wall ◽  
Wall Layer ◽  
Lipid Globule ◽  
Large Numbers ◽  
Microscopie Électronique ◽  
Hyphal Bodies ◽  
Hyphal Body ◽  
Reserve Lipid ◽  
Dormant Spore

The multinucleate hyphal bodies of Conidiobolus obscurus are characterized by a striated wall which does not react with Thiéry's stain used to detect free α glycol groups. In the developing mycelial zone, the protoplasm contains microvesicles and electron-dense corpuscles; during ageing of the mycelium, lipid globules varying in size according to the age of the cell and vesicles with dense inclusions are observed in large numbers, whereas the endoplasmic reticulum shows little development. The onset of sporulation is characterized by protoplasmic condensation at a particular point in the hyphal body through successive accumulations of cicatricial partitions. The young prespore is a spherical organ; its wall has the same structure as that of the mycelium, and it contains more or less the same organelles as the hyphal protoplasm. The first sign that the prespore is developing into a spore is the deposition of a very thick inner wall layer (tripartite layer). The inner makeup of the azygospore has all the features of a dormant spore of low metabolic activity having a huge reserve lipid globule. At the onset of germination, the spore wall and the central lipid globule are progressively digested. A new wall entity is synthesized. There is a proliferation of multivesicular and multilaminate bodies. The emergence of the germ tube results from the rupture of the original outer layer of the spore. Results are compared with those observed in various resistance organs of zygomycetes and oomycetes, and discussed in relation to functional metabolic pathways during sporogenesis or germination. [Journal translation]

scholarly journals Bacteria Associated with Spores of the Arbuscular Mycorrhizal Fungi Glomus geosporum and Glomus constrictum

2005 ◽  
Vol 71 (11) ◽  
pp. 6673-6679 ◽  
Author(s):  
David Roesti ◽  
Kurt Ineichen ◽  
Olivier Braissant ◽  
Dirk Redecker ◽  
Andres Wiemken ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Plantago Lanceolata ◽  
Arbuscular Mycorrhizal ◽  
Spore Wall ◽  
Wall Layer ◽  
Single Spore ◽  
Bacterial Populations ◽  
Glomus Geosporum

ABSTRACT Spores of the arbuscular mycorrhizal fungi (AMF) Glomus geosporum and Glomus constrictum were harvested from single-spore-derived pot cultures with either Plantago lanceolata or Hieracium pilosella as host plants. PCR-denaturing gradient gel electrophoresis analysis revealed that the bacterial communities associated with the spores depended more on AMF than host plant identity. The composition of the bacterial populations linked to the spores could be predominantly influenced by a specific spore wall composition or AMF exudate rather than by specific root exudates. The majority of the bacterial sequences that were common to both G. geosporum and G. constrictum spores were affiliated with taxonomic groups known to degrade biopolymers (Cellvibrio, Chondromyces, Flexibacter, Lysobacter, and Pseudomonas). Scanning electron microscopy of G. geosporum spores revealed that these bacteria are possibly feeding on the outer hyaline spore layer. The process of maturation and eventual germination of AMF spores might then benefit from the activity of the surface microorganisms degrading the outer hyaline wall layer.

Ultrastructural changes in the cell surface of Coelomomyces punctatus infecting mosquito larvae

1976 ◽  
Vol 54 (13) ◽  
pp. 1419-1437 ◽  
Author(s):  
Martha J. Powell
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Granular Material ◽  
Fat Body ◽  
Vegetative Stage ◽  
Ultrastructural Changes ◽  
Anopheles Quadrimaculatus ◽  
Advanced Stages ◽  
Hyphal Bodies ◽  
Hyphal Body

As the fungus Coelomomyces punctatus develops in the coelomic cavity of the mosquito Anopheles quadrimaculatus, the conformation of the plasma membrane and extracellular coat of the fungus changes markedly. The vegetative stage was surrounded by a granular and fibrillar extracellular coat which reacted positively in the silver methenamine procedure for the localization of polysaccharides. Numerous simple, branched or contorted cytoplasmic protuberances covered the irregularly shaped hyphal bodies. The surface of the hyphal body adjacent to the fat body of the mosquito had occasional involutions of the plasma membrane sheathed by cisternae of endoplasmic reticulum. In contrast with these hyphal bodies, cytoplasmic protuberances were spaced at wide intervals along filamentous hyphae. Aborting thalli were contorted and deeply lobed. The plasma membrane was smooth, and cytoplasmic protuberances were absent on other hyphae and hyphal bodies, particularly at advanced stages of infection. Instead unattached vesicles, morphologically similar to the protuberances found on some thalli, were embedded in granular material clustered around the smooth plasma membrane of these thalli. Mosquito hemocytes appeared to engulf these vesicles and granular material. As the vegetative stage was transformed into the reproductive stage, a newly formed, compact extracellular layer surrounded the sporangial initial. Later, a darkly staining wall appeared around the resting sporangium. Cisternae of endoplasmic reticulum consistently subtended thin areas in this pitted wall.

An inexpensive medium for mass fermentation production of Entomophaga aulicae hyphal bodies competent to form conidia

1993 ◽  
Vol 39 (6) ◽  
pp. 588-593 ◽  
Author(s):  
Richard A. Nolan
Keyword(s):  
Growth Medium ◽  
Entomopathogenic Fungus ◽  
Basal Medium ◽  
Fermentation Medium ◽  
Eastern Hemlock ◽  
Developmental Sequence ◽  
Hyphal Bodies ◽  
Hyphal Body ◽  
Hemlock Looper ◽  
Single Medium

A mass fermentation medium for growth and morphogenesis of the entomopathogenic fungus Entomophaga aulicae was developed. This fungus is a major pathogen of larval eastern hemlock looper and spruce budworm. The medium consists of a basal medium plus 0.8% tryptic soy broth and 0.4% calcium caseinate. This medium is a major breakthrough in that (i) the E. aulicae developmental sequence from protoplast inoculum to hyphal bodies competent to form conidia can be carried out in a single medium without adjustment, (ii) by examining the fermentation product it can be determined if conidia can be produced prior to engaging in costly field spraying, (iii) this medium supports the growth of E. aulicae isolates from different geographical areas, (iv) the medium is relatively inexpensive, (v) the hyphal bodies are easily separated from the spent growth medium, and (vi) the hyphal body yield is high.Key words: Entomophaga aulicae, mass fermentation medium, hyphal bodies, conidia, insect biocontrol.

Physiological studies with the fungus Entomophaga aulicae during morphogenesis in three different media under fermentation conditions

1993 ◽  
Vol 39 (7) ◽  
pp. 701-708
Author(s):  
Richard A. Nolan
Keyword(s):  
Amino Acid ◽  
Serum Albumin ◽  
Glucose Utilization ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Basal Medium ◽  
Fermentation Conditions ◽  
Hyphal Bodies ◽  
Hyphal Body ◽  
Body Production

The effects of three different media on amino acid uptake and production and glucose and oxygen utilization during protoplast growth and hyphal body production by the fungus Entomophaga aulicae under fermentation conditions were studied. The three media consisted of a basal medium plus either (i) 2.8% fetal calf serum, (ii) 0.8% tryptic soy broth plus 0.4% bovine serum albumin, or (iii) 0.8% tryptic soy broth plus 0.4% calcium caseinate. The protoplasts grew most rapidly (initial peaks on days 2 and 3) and hyphal bodies were detected first (day 3) in the media containing albumin and caseinate. The day 9 hyphal body yields were 3.1 × 107, 7.5 × 108, and 3.1 × 109/10 L in media containing the serum, albumin, and caseinate, respectively. Growth in the albumin and caseinate media also gave the first detectable glucose utilization (days 2 and 3, respectively) and this rapidly increased to 94.9 and 90.6% utilization, respectively, on day 4. Oxygen and glucose utilization were closely related. During protoplast growth prior to hyphal body production, the only common pattern detected was the initial utilization of glutamine in serum- and caseinate-containing media. During the initial period of hyphal body production, cysteic acid, threonine, serine, asparagine, leucine, tyrosine, phenylalanine, and arginine were first utilized and glycine, alanine, and ammonia were first produced in the albumin and caseinate media. At this time (days 3–5), glutamine, proline, cystine, and tryptophan were first utilized and valine and histidine were produced in the albumin medium, and methionine was first utilized and cystathionine produced in the caseinate medium. Four main patterns of overall amino acid utilization and production were identified. The delay in major protoplast growth in the basal medium plus fetal calf serum is felt to result from inhibition by free fatty acids in the serum. Protein utilization was not detected and its main function is considered to be enhancement of protoplast stability against fermentation shear forces.Key words: Entomophaga aulicae, physiology, fermentation growth, protoplasts, hyphal bodies.

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.

The Partition Layer of Common Bunt Teliospores

2001 ◽  
Vol 7 (S2) ◽  
pp. 174-175
Author(s):  
W.M. Hess ◽  
D.J. Weber
Keyword(s):  
Chemical Nature ◽  
Spore Wall ◽  
Wall Layer ◽  
Smut Fungi ◽  
Common Bunt ◽  
Spore Viability ◽  
Important Group ◽  
Tilletia Laevis ◽  
Ultrastructural Characteristics ◽  
Basidiomycete Fungus

The basidiomycete fungus, Tilletia constitutes the most important group of smuts economically as they infect cereal grains which provide a major portion of the world’s food supply. The teliospores of the smuts which have been studied have a spore wall layer called the partition layer or the striated zone which is very resistant to fixatives and resins used for electron microscopy. We assume that the chemical nature of this wall layer is the primary factor to prevent spore desiccation and to maintain spore viability for many years. Teliospores of Tilletia tritici (Bjerk.) Wint. (formerly T. caries), T. controversa Kühn, T. indica Mitra, and Neovossia horrida (Tak.) Padwick and Khan all have a reticulated exterior spore layer (sheath). Common bunt, Tilletia laevis Kühn (formerly T. foetida) teliospores lack this exterior reticulated layer, but are also resistant to spore desiccation and maintain viability for many years. Therefore, the purpose of this study was to compare the ultrastructural characteristics of the partition layer of T. laevis teliospores with the partition layer of other teliospores of smut fungi which have been studied.

Acaulospora papillosa, a new mycorrhizal fungus from NE Brazil, and Acaulospora rugosa from Norway

Phytotaxa ◽  
2016 ◽  
Vol 260 (1) ◽  
pp. 14 ◽  
Author(s):  
CAMILLA M.R. PEREIRA ◽  
LEONOR C. MAIA ◽  
IVÁN SÁNCHEZ-CASTRO ◽  
JAVIER PALENZUELA ◽  
DANIELLE K.A. SILVA ◽  
...  
Keyword(s):  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Single Species ◽  
Spore Wall ◽  
Wall Layer ◽  
Northeastern Brazil ◽  
Tropical Atlantic ◽  
Spore Surface ◽  
Phylogenetic Placement ◽  
Light Yellow

A new arbuscular mycorrhizal species, Acaulospora papillosa, was isolated from the biological reserve ‘Saltinho’ within a coastal tropical Atlantic forest of the ‘Mata Atlântica’ biome in Pernambuco State of Northeastern Brazil. It was trapped and propagated as single species cultures on Zea mays. The spores are yellow white to light yellow to creamy, globose to subglobose, 69–100(–110) × 65–93(–101) µm. The spore surface is roughened as crowded with fine papillae, which are formed on the outermost, evanescent to semi-persistent spore wall layer. These papillae may disintegrate or completely disappear as the spores age and the layer becomes completely evanescent. Phylogenetically, the fungus clusters together with several small-spored Acaulospora species having smooth spore surfaces, such as A. delicata, A. longula, A. morrowiae and A. mellea. In the Acaulospora clade, A. papillosa is the third taxon known to have a roughened spore surface, in addition to A. dilatata and A. rugosa. The phylogenetic placement of A. rugosa is provided, together with colored illustrations of the spore morphology. The isolation of A. papillosa from such protected nature reserves as ‘Saltinho’ further supports the need to protect these areas and determine the biodiversity of beneficial microorganisms.

The effect of glucose concentration and light on thallospore ultrastructure in Ellisomyces anomalus (Thamnidiaceae, Mucorales)

1984 ◽  
Vol 62 (12) ◽  
pp. 2677-2687 ◽  
Author(s):  
Gordon W. Beakes ◽  
Galba M. Campos-Takaki ◽  
Massonori Takaki
Keyword(s):  
Freeze Fracture ◽  
Spore Wall ◽  
Wall Layer ◽  
Structural Differences ◽  
Low Glucose ◽  
Electron Microscopical ◽  
Gilbertella Persicaria ◽  
Effect Of Glucose ◽  
Glycogen Particles ◽  
Fracture Electron

The development of chains of thallospores in the mucoraceous fungus Ellisomyces anomalus has been examined using scanning, thin section, and freeze-fracture electron microscopical techniques. The development and cytology of spores formed on high-glucose (HG, 4.0%) and low-glucose (LG, 0.06%) media, under both light and dark conditions, have been compared. The vegetative hyphae of spores on LG media accumulate glycogen particles in their cytoplasm but contain very little lipid. The cytoplasm of HG hyphae is packed with lipid globules. The thallospores are delimited by septa, which as in most other mucoraceous fungi are perforated by plasmodesmatalike pit connections. A thick secondary (spore) wall layer is accreted as the spores swell. Although mature thallospores on LG and HG media are similar in their external morphology, they show internal differences. HG spores are thicker walled and contain abundant lipid and glycogen reserves. LG spores contain relatively little lipid and are more highly vacuolate. The only structural differences observed between the carotene-rich, light-grown spores and their dark-grown counterparts is an increase in lipid globule electron density and an overall enhancement of membrane staining properties. The mature thallospores secede from the parent hyphae by both shizolytic (septum splitting) and rhexolytic (circumcissile hyphal splitting) mechanisms. From a developmental standpoint it is suggested the thallospores of Ellisomyces resemble thallic arthric conidia (arthrospores), simiar to those produced by Mucor rouxii, more closely than true chlamydospores, such as those produced by Gilbertella persicaria and Mucor mucedo.

Ultrastructural localization of carbohydrate in cell walls of the entomogenous hyphomycete Nomuraea rileyi

1992 ◽  
Vol 38 (5) ◽  
pp. 377-386 ◽  
Author(s):  
J. C. Pendland ◽  
D. G. Boucias
Keyword(s):  
Cell Walls ◽  
Ultrastructural Localization ◽  
Outer Wall ◽  
Nomuraea Rileyi ◽  
Larval Hemolymph ◽  
Gold Conjugate ◽  
Hyphal Bodies ◽  
Hyphal Body ◽  
Host Parasite ◽  
Germ Tubes

Several probes were used in this ultrastructural study to localize polysaccharides in cell walls on conidial germ tubes, hyphal bodies, and mycelia of the entomogenous hyphomycete Nomuraea rileyi. With the exception of galactose, labelling patterns did not vary from one morphological stage to another. Galactose, which was localized by using a monoclonal antibody to a galactose-specific lectin purified from insect larval hemolymph, was absent from cell walls of hyphal bodies and conidia but was present on germ-tube and mycelial surfaces. Chitin (N-acetylglucosamine), labelled with a wheat-germ agglutinin-ferritin conjugate, was present in the middle regions of lateral walls and septa, and β1-4 glucans were located in the middle and inner regions, as indicated by binding of a cellulase-gold conjugate. An anti-laminaribiose antibody was used to label β1-3 glucans present in the outer wall areas and inner regions near the plasmalemma. The location of mannose residues as indicated by concanavalin A - ferritin binding was similar to that of the β1-3 glucans; vesicle-like structures were also labelled. None of the probes labelled the outer conidial pellicle or exocellular sheath surrounding germ tubes, and labelling of mycelial sheath was inconsistent. The absence of galactose from Nomuraea hyphal body walls is discussed in terms of host-parasite interaction. Key words: Nomuraea rileyi, entomopathogenic fungi, glycoconjugates, lectins, monoclonal antibodies.

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.

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