A new genus of the anaerobic gut fungi (Neocallimastigales), Cyllamyces aberensis gen.nov. sp.nov., with bulbous holdfast, branched sporangiophores and limited polycentric thallus development is described. The fungus was isolated from fresh cattle faeces. Free-swimming zoospores were spherical, uninucleate, and uniflagellate. After encystment, zoospores germinated and gave rise to a single, bulbous holdfast. One or several branched sporangiophores were produced from different locations on the holdfast, each bearing several spherical sporangia. DAPI staining of thalli indicated that nuclei were present in the holdfast, sporangiophores, and sporangia. As many as 12 sporangia were observed per thallus on up to 5 sporangiophores, with zoosporogenesis beginning 16–18 h after encystment. Zoospore ultrastructure was examined by transmission electron microscopy and found to be similar to that reported for other anaerobic chytrid fungi. Organelles were evenly distributed throughout the cell, except for the posteriorly attached flagellum and associated attachment apparatus, the hydrogenosomes, which were mainly situated in the posterior parts of the cell and a posteriorly directed, beak-shaped nucleus. Limited polycentric thallus development (including branched sporangiophores), the possession of a single bulbous holdfast and the absence of rhizoids were stable features of this fungus that distinguished it from the other five genera of gut fungi. Therefore, we have used these characteristics to assign the fungus to a new genus, Cyllamyces, with the specific name C. aberensis.Key words: rumen, fungal taxonomy, Neocallimastigales, chytrid, zoospore ultrastructure.

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The aim of this experiment was to determine the chemical composition of six commonly utilized fodder trees and shrub species in Turkey, namely Glycrrhiza glabra L, Arbutus andrachne, Carpinus betilus, Juniperus communis, Quercus libari L and Pistica lentiscus and its relationship with gas production and estimated parameters when incubated with rumen fluid in vitro. There were significant (p<0.001) differences between leaves in terms of crude protein (CP), acid detergent fiber (ADF), total condensed tannin (TCT), bound condensed tannin (BCT) and soluble condensed tannin (SCT). Crude protein contents ranged from 5.74% (Juniperus communis) to 12.59% (Glycrrhiza glabra L). Acid detergent fiber contents ranged from 25.14% (Glycrrhiza glabra L) to 39.23% (Juniperus communis). Total condensed tannin (TCT) contents of leaves ranged from 4.34% (Quercus libari L) to 20.34% (Juniperus communis). Acid detergent fiber (ADF) and total condensed tannin contents of leaves were negatively correlated with gas productions and some estimated parameters. Potential gas productions (A) of Glycrrhiza glabra L, Arbutus andrachne, Quercus libari L and Pistica lentiscus were significantly (p<0.001) higher than those of Carpinus betilus and Juniperus communis whereas gas production rate (µ 24 ) of Pistica lentiscus was significantly (p<0.001) higher than the others. Time (h) to produce 50% of total gas pool size (T 50 ) of Juniperus communis was significantly (p<0.001) lower than that of Carpinus betilus whereas time (h) to produce 90% of total gas pool size (T 90 ) of Juniperus communis was significantly lower than the others except for Pistica lentiscus. The metabolizable energy (ME) contents of leaves ranged from 8.86 to 10.39 MJ kg -1 DM. The results obtained in this study suggested that browse species had a significant effect on chemical composition, gas production and estimated parameters of leaves. Leaves from Glycrrhiza glabra L with a considerable amount of CP had a high rank value in terms of ME. Therefore leaves from Glycrrhiza glabra L may have a high potential value for small ruminant animals in terms of rumen and whole digestibility. Leaves from other species studied require protein supplementation when they are the only feed consumed by ruminant animals.

Two new isolates of the gut fungi were obtained from the rumen digesta and faeces of a cow. These isolates, designated Anaeromyces following rDNA typing, displayed a polycentric growth habit but differed from all other gut fungi in that they were able to survive in the laboratory for considerable periods without the need for sub-culture. Light microscopy of preparations from old liquid-grown cultures revealed the presence of DNA-containing spores with two or four chambers. A comparative evaluation of the growth produced when fresh media were inoculated with a sample originating from young or old cultures revealed that active growth was delayed with the inoculum from the older culture. We propose that the chambered spores observed in these cultures provide an alternative path in the life cycle of these fungi and may function as a resting stage within the anaerobic environment of the herbivore gut.