Unusual ascospore germination in Hypoxylon fragiforme: first seps in the establishment of an endophytic symbiosis

1990 ◽  
Vol 68 (12) ◽  
pp. 2571-2575 ◽  
Author(s):  
I. H. Chapela ◽  
O. Petrini ◽  
L. E. Petrini
Keyword(s):  
Germ Tube ◽  
Initial Step ◽  
Wall Layer ◽  
Flexible Structure ◽  
Specific Factor ◽  
Recognition Mechanism ◽  
Ascospore Germination ◽  
Host Fungus ◽  
High Degree ◽  
Rigid Shell

An unusual germination mechanism in ascospores of Hypoxylon fragiforme is described and illustrated. In this xylariaceous, endophytic fungus, germination always involved the emergence of a bivalved, flexible structure from an outer rigid shell, formed by a differentiated transparent wall layer, and resulted in the exposure of the cell body. The series of fast movements leading to the emergence of activated ascospores from their shells was termed spore eclosion. Eclosion was a necessary initial step of germination, but eclosion without germ-tube production could be obtained by cycloheximide treatment. Major changes involved in eclosion occurred within a few seconds, some minutes after discharge of ascospores onto the host material (Fagus sylvatica). We postulate the existence of a host-derived, diffusible, specific factor eliciting those changes. This sophisticated recognition mechanism indicates a high degree of specialization of H. fragiforme to its endophytic symbiosis with beech trees. Key words: eclosion, tree, Fagus, Hypoxylon, host–fungus recognition.

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 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.

Factors influencing ascospore germination in three species of Sporormiella

1977 ◽  
Vol 55 (14) ◽  
pp. 1908-1914 ◽  
Author(s):  
Shirin Asina ◽  
Kanti Jain ◽  
R. F. Cain
Keyword(s):  
Sodium Acetate ◽  
Germ Tube ◽  
Optimal Level ◽  
Physical Factors ◽  
Optimal Temperature ◽  
Factors Influencing ◽  
Ascospore Germination ◽  
Energy Maximum ◽  
Ph Range ◽  
Exogenous Source

Ascospore germination of Sporormiella intermedia, S. isomera, and S. minima requires sodium acetate as an exogenous source of energy. Maximum ascospore germination occurs at a concentration of 5.0 g/ℓ of sodium acetate in the medium. Among the physical factors studied, the pH of the medium was found to be crucial: germination occurred within a very narrow pH range (5.0–7.0) and reached an optimal level at pH 5.5. The ascospores of S. intermedia and S. isomera germinated between 10 and 30 °C while those of S. minima germinated between 10 and 40 °C. The optimal temperature varied for each species (10–20 °C for S. intermedia; 20–25 °C for S. isomera; 30–35 °C for S. minima). At 30 °C and above, a globose vesicle formed in all three species before the formation of the germ tube. Light had no influence on ascospore germination, nor were external supplies of nitrogen or vitamins necessary for spore germination.

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.

Interactions between Sclerotinia sclerotiorum and Epicoccum purpurascens

1991 ◽  
Vol 69 (11) ◽  
pp. 2503-2510 ◽  
Author(s):  
Ting Zhou ◽  
R. D. Reeleder ◽  
S. A. Sparace
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Hyphal Growth ◽  
White Mold ◽  
Antifungal Compounds ◽  
Sterile Culture ◽  
Pod Yield ◽  
Culture Filtrates ◽  
Ascospore Germination

Sterile culture filtrates of Epicoccum purpurascens decreased severity of white mold of bean and increased pod yield when applied prior to inoculation of beans with Sclerotinia sclerotiorum. Extracts of these culture filtrates inhibited ascospore germination and mycelial growth of S. sclerotiorum. Similar inhibition of hyphal growth of S. sclerotiorum occurred when dual cultured with E. purpurascens. Contact and penetration of hyphae of S. sclerotiorum by hyphae of E. purpurascens occurred rarely on agar-covered slides and was not observed on flower petals. Inhibition of ascospore germination and germ-tube elongation occurred on agar-covered slides where E. purpurascens had been grown previously; however, addition of nutrients decreased inhibition. Colonization of bean flowers by E. purpurascens reduced white mold incidence. The degree of disease control was affected by addition of nutrients and whether or not colonized flowers were autoclaved. Key words: antifungal compounds, competition, biological control, white mold, Phaseolus.

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 Firms’ profitability from firm-specific factor, environmental turbulence, and macroeconomic: evidence from Taiwan’s food industry – A review

2019 ◽  
Vol 65 (No. 2) ◽  
pp. 93-101
Author(s):  
Joe-Ming Lee ◽  
Shiu-Wan Hung ◽  
Chiao-Ming Li
Keyword(s):  
Firm Performance ◽  
Food Industry ◽  
Negative Relationship ◽  
Environmental Turbulence ◽  
Smooth Transition ◽  
Specific Factor ◽  
Structural Capital ◽  
Smooth Transition Regression ◽  
Customer Capital ◽  
High Degree

After a series of shocking domestic food safety scandals in the past few years, environmental concerns have risen in the eyes of the public. The aim of this paper is to analyse the relationships among firm performance, customer capital, R&D innovation, structural capital, firm asset, environmental turbulence, and the macroeconomy by using the panel data model on Taiwanese food industry firms during 2010–2016 and by examining the results of the multiple regime panel smooth transition regression (MR-PSTR) model. The findings show that environmental turbulence and the misery index have a negative relationship on firms’ performance, while there is a positive relationship between customer capital and firm performance. However, under high environmental turbulence, customer capital and firm performance are negatively related, meaning that a firm’s marketing promotion will be ineffective. This study recommends that the food industry establish a high degree of trust from society and consumers. It is also important for the food industry to establishes a positive attitude towards quality requirements.

scholarly journals Social recognition in wild fish populations

2007 ◽  
Vol 274 (1613) ◽  
pp. 1071-1077 ◽  
Author(s):  
Ashley J.W Ward ◽  
Michael M Webster ◽  
Paul J.B Hart
Keyword(s):  
Spatial Resolution ◽  
Gasterosteus Aculeatus ◽  
Social Recognition ◽  
Wild Populations ◽  
Recognition Mechanism ◽  
Temporal Flexibility ◽  
Social And Physical Environment ◽  
Focal Fish ◽  
High Degree ◽  
Recent Laboratory

The ability of animals to gather information about their social and physical environment is essential for their ecological function. Odour cues are an important component of this information gathering across taxa. Recent laboratory studies have revealed the importance of flexible chemical cues in facilitating social recognition of fishes. These cues are known to be mediated by recent habitat experience and fishes are attracted to individuals that smell like themselves. However, to be relevant to wild populations, where animals may move and forage freely, these cues would have to be temporally flexible and allow spatial resolution. Here, we present data from a study of social recognition in wild populations of three-spined sticklebacks ( Gasterosteus aculeatus ). Focal fish preferentially associated with conspecifics from the same habitat as themselves. These preferences were changed and updated following translocation of the focal fish to a different site. Further investigation revealed that association preferences changed after 3 h of exposure to different habitat cues. In addition to temporal flexibility, the cues also allowed a high degree of spatial resolution: fish taken from sites 200 m apart produced cues that were sufficiently different to enable the focal fish to discriminate and associate with fish captured near their own home site. The adaptive benefits of this social recognition mechanism remain unclear, though they may allow fish to orient within their social environment and gain current local information.

Ultrastructural studies of primary spores of Conidiobolus, Erynia, and related Entomophthorales

1989 ◽  
Vol 67 (9) ◽  
pp. 2576-2589 ◽  
Author(s):  
J. P. Latgé ◽  
D. F. Perry ◽  
M. C. Prévost ◽  
R. A. Samson
Keyword(s):  
Outer Layer ◽  
Germ Tube ◽  
Spore Wall ◽  
Wall Layer ◽  
Spore Formation ◽  
Dense Layer ◽  
Nuclear Ultrastructure ◽  
Ultrastructural Studies ◽  
Thin Electron ◽  
Definition Of

Wall development during primary spore formation, discharge, and germination of Entomophthorales is emphasized in ultrastructural studies of Conidiobolus, Entomophaga, Neozygites, and Erynia. In the fungi examined, spore and sporophore walls consist of a thick, electron-translucent inner layer and a thin, electron-dense outer layer. During spore formation, cytoplasm of the supporting sporophore cell migrates into the spore initial. As the former cell empties, a septum develops. Discharge is caused by inversion of the papillum, which lacks the electron-dense layer. Only in Erynia did the two spore wall layers separate upon impact. Intracytoplasmic organization of the primary spore is typical of the Zygomycotina; the morphology of organelles was characteristic of species, whereas nuclear ultrastructure was consistent within genera. Conidiobolus nuclei have a prominent nucleolus that lacks heterochromatin, in contrast with the other genera where large patches of heterochromatin were observed. Upon germination, no rupture of the spore outer layer was observed other than at points of germ tube emergence. The germ tube wall was continuous with the inner spore wall layer. The results are discussed in reference to Entomophthorales taxonomy and definition of the terms conidium and monosporous sporangiolum.

scholarly journals Genetic Diversity of Bubalus bubalis in Germany and Global Relations of Its Genetic Background

2021 ◽  
Vol 11 ◽  
Author(s):  
Antonia Noce ◽  
Saber Qanbari ◽  
Rayner González-Prendes ◽  
Julia Brenmoehl ◽  
María Gracia Luigi-Sierra ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Initial Step ◽  
Bubalus Bubalis ◽  
Domestic Water ◽  
High Genetic Diversity ◽  
European Continent ◽  
The Sustainable Development ◽  
Worldwide Distribution ◽  
High Degree

This is the first study to explore the genetic diversity and population structure of domestic water buffalo (Bubalus bubalis) in Germany and their potential relations to herds in other parts of Europe or worldwide. To this end, animals from different herds in Germany, Bulgaria, Romania, and Hungary were genotyped and compared to genotypes from other populations with worldwide distribution and open to the public. The pilot study analyzed population structure, phylogenetic tree, and inbreeding events in our samples. In buffalos from Germany, a mixed genetic make-up with contributions from Bulgaria (Murrah breed), Romania, and Italy was found. All in all, a high degree of genetic diversity was identified in European buffalos, and a novel genotype was described in Hungarian buffalos by this study. We demonstrate that European buffalos stand out from other buffalo populations worldwide, supporting the idea that buffalos have not completely disappeared from the European continent during the late Pleistocene. The high genetic diversity in European buffalos seems to be an excellent prerequisite for the establishment of local breeds characterized by unique traits and features. This study may also be considered as an initial step on the way to genome characterization for the sustainable development of the buffalo economy in Germany and other parts of Europe in the future.

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