Neocallimastix: a comparative morphological study

Abstract

The development from zoospore to a mature thallus in Neocallimastix sp. isolated from a Georgia cow was studied at the light microscope level. The zoospore had 9–14 posteriorly directed flagella, and its shape varied from amoeboid in agar to ovoid in broth. Encysted zoospores developed endogenously into extramatrical ovoid or spherical incipient zoosporangia with extensively branched intramatrical rhizoids that often had constrictions. Sessile mature zoosporangia varied in shape, and zoospores were fully formed within zoosporangia before release through an apical pore. In agar, zoospores encysted close to the parent zoosporangium and developed endogenously into second generation zoosporangia or exogenously into elongate thalli. At maturity, an elongate thallus was made up of a sporangium, a sporangial stalk, a cyst, and branched rhizoids. Elongate thalli were sometimes formed in broth. Melanized resting sporangia were formed on branched thalli in old (> 36 h) cultures. Two isolates of Neocallimastix frontalis from a cow and sheep and Neocallimastix patriciarum were grown under the same conditions as our isolate, and the morphology of zoospore, zoosporangium, and melanized sporangium of the four isolates were compared. In broth, the isolates developed in the same manner and formed elongate thalli and melanized sporangia as described for our isolate. There is insufficient justification, based on morphology alone, for separating the four isolates. The importance of basic light microscopy is discussed. Key words: Neocallimastix, development, morphology.

Characterization of an anaerobic fungus from Ilama faeces

“…The location of these structures close to the motility apparatus was also found in the rumen holotrichs Dusytricha ruminuntium and Isotricha sp. (Yarlett et al, 1981. In zoospores of Neocallimastix sp.…”

“…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).…”

Mechanisms of Hyphal Tip Growth: Tube Dwelling Amebae Revisited

“…(3) Chytridiomycete zoospores are often ameboid (Barr, 1986;Couch, 1935;Karling, 1938;Longcore et al, 1999;Orpin, 1975;Powell, 1987;Sparrow, 1960;Wubah et al, 1991). One genus lacks flagella, its spores move entirely by ameboid movement and it is named Amoebochytrium (Zopf, 1884).…”

A fast and reliable procedure for spore collection from anaerobic fungi: Application for RNA uptake and long-term storage of isolates

“…In addition, most previous reports did not conduct any viability measurements on the released spores. More importantly, the above approaches depend on the presence of free spores in the culture supernatant [7,8,[10][11][12]47]. Such dependency on the presence of free spores could be problematic in monocentric species (e.g.…”

“…AMT transformation, RNAi). Similarly, apart from microscopic-based observations [5][6][7][8][9][10][11][12], developmental biology studies seeking to understand the physiological, structural, regulatory, and gene expression patterns associated with various stages of development within the AGF complex life cycle have been extremely sparse.…”