Morphology and development of rumen fungi: Neocallimastix sp., Piromyces communis, and Orpinomyces bovis gen.nov., sp.nov.

Abstract

Developmental stages and morphological variation are described for three species of fungi from the rumen of a Holstein steer. Neocallimastix sp. is monocentric and has endogenous, rarely exogenous, sporangial development. Piromyces communis is monocentric, rarely polycentric, and has both endogenous sporangium development and exogenous sporangia on sporangiophores. Orpinomyces bovis is described for a polycentric fungus with terminal and intercalary sporangiophore complexes that develop from the rhizomycelium, and polyflagellate zoospores. The advantages and limitations of the light microscope and the enigmatic problem of classification of diverse and polymorphic rumen fungi are discussed.

Characterization of an anaerobic fungus from Ilama faeces

“…All anaerobic fungi have been assigned to the family of the Neocallimasticaceae of the Spizellomycetales (Chytridiomycetes) (Barr, 1988). Within this family six genera have been recognized : Neocallimastix (Heath et al, 1983 ;Orpin, 1975 ;Orpin & Munn, 1986), Piromyces (previously Piromonas) (Breton et al, 1991;Li et al, 1990;Orpin, 1977 a), Caecomyces (previously Sphaeromonas) (Orpin, 1976;Gold et al, 1988), Anaeromyces (Breton et al, 1990), Orpinomyces (Barr et al, 1989) (Ho et al, 1990), which differ from each other primarily in the number of flagella attached to their zoospores and in the appearance of their thallus. Other morphological characteristics, such as shape and size of sporangia and zoospores, have been used in the characterization of anaerobic chytridiomycetes (Barr et al, 1989 ;Breton et al, 1989Breton et al, , 1990Breton et al, , 1991Lowe et al, 1987;Orpin, 1975Orpin, , 1976Orpin, , 1977aWubah et al, 1991).…”

Comparison of growth characteristics of anaerobic fungi isolated from ruminant and non-ruminant herbivores during cultivation in a defined medium

“…Subsequently polycentric species have been described, e.g. Orpinomyces bovis (Barr et al, 1989) and Neocallimastix joyonni (Breton et al, 1989). Up to now, six anaerobic fungi isolated from foregut fermenters (sheep, cow) have been classified, namely : Neocallimastix patriciarum (Orpin & Munn, 1986), Neocallimastix frontalis (Heath et al, 1983), Neocallimastix joyonni (Breton et al, 1989), Piromyces communis (Orpin, 1977), Caecomyces communis (Orpin, 1976(Orpin, , 1988 and Orpino--myces bovis (Barr et al, 1989).…”

Morphology of three polycentric rumen fungi and description of a procedure for the induction of zoosporogenesis and release of zoospores in cultures

“…1 b). The morphological characteristics of LL and LC2 appeared similar to those of Orpinornyces (Barr et al, 1989) and Neocallimastix joyonii (Breton et al, 1989). Although LL and LC2 seem to be morphologically similar, it is not possible at this stage to acertain whether they belong to the same species.…”

“…Phillips (1988) also described the morphologies of three apparently different polycentric rumen fungi: one of these did not produce any zoospores under the culture conditions used, although sporangia were formed abundantly; the other two produced zoospores only infrequently. Subsequently, a polycentric species with polyflagellate zoospores, Orpinomyces bovis (Barr et al, 1989), was formally described and assigned its taxonomic position. Breton et al (1989) described a polycentric fungus with polyflagellate zoospores and named it Neocallimastix joyonii.…”