Neocallimastix Hydrogenosomes

Although there have been several reports of putative Neocallimastix sp. hydrogenosomal proteins in silico, few have actually been localized to hydro- 

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Benchimol M, Durand R, Almeida JCA. 1997. A double membrane surrounds the hydrogenosomes of the anaerobic fungus Neocallimastix frontalis. FEMS Microbiol Lett 154 277-82. 

Brondijk THC, Durand R, van der Giezen M, et al. 1997. scsb, a cDNA encoding the hydrogenosomal beta subunit of succinyl-CoA synthetase from the anaerobic fungus Neocallimastix frontalis. Mol Gen Genet 253 315-23. 

Marvin-Sikkema FD, Driessen AJM, Gottschal JC, Prins RA. 1994. Metabolic energy generation in hydrogenosomes of the anaerrobic fungus Neocallimastix evidence for a functional relationship with mitochondria. Mycol Res 98 205-12. 

Marvin-Sikkema FD, Gomes TMP, Grivet JP, et al. 1993. Characterization of hydrogenosomes and their role in glucose metabolism of Neocallimastix sp 12. Arch Microbiol 160 388-96. 

Voncken FGJ, Boxma B, van Hoek A, et al. 2002. A hydrogenosomal Fe-hydrogenase from the anaerobic chytrid Neocallimastix sp L2. Gene 284 103-12. 

Biagini GA, van der Giezen M, Hill B, Winters C, Lloyd D (1994) Ca2+-accumulation in the hydrogenosome of Neocallimastix frontalis a mitochondrial-like physiological role. FEMS Microbiol Lett 149 227-232... 

Yarlett N, Orpin CG, Munn EA, Yarlett NC, Greenwood CA (1986) Hydrogenosomes in the rumen fungus Neocallimastix patriciarum. Biochem J 236 729-739 Yong R, Searcy DG (2001) Sulfide oxidation coupled to ATP synthesis in chicken liver mitochondria. Comp Biochem Physiol 129 129-137 Zebe E (1991) Arthropods. In Bryant C (ed) Metazoan Life Without Oxygen. Chapman and Hall, London, pp 218-237... 

Fig. 4 Thin sections of the fungal hydrogenosome (H) from Neocallimastix frontalis. In a there is one hydrogenosome in the process of division and the inner hydrogenosomal membrane is in process of septum formation. Note that there is another hydrogenosome with a double membrane, which is not in process of division. In b all the hydrogenosomes are dividing, presenting internal septa. Bars = 100 nm. (From Benchimol et al. 1997)...

The hydrogenosomes of the anaerobic fungus Neocallimastix are round or elongated structures, always enveloped by two distinct but tightly apposed membranes (Figs. 4a,b, 5b) (van der Giezen et al. 1997 Benchimol et al. 1997). 

The hydrogenosomal metabolism has been studied in more detail in the chytridiomycetes Piromyces and Neocallimastix. Notably, the hydrogenosomes of these organisms are clearly different from those known of tri-chomonads and anaerobic ciliates, structurally and metabolically. Most importantly, the hydrogenosomes of Neocallimastix sp. L2 and Piromyces sp. E2 contain PFL as key enzyme, and not PDH (as in N. ovalis) or PFO (as in Trichomonas vaginalis) (Fig. 2). 

Fig. 4 Serial sectioning of the hydrogenosomes of Neocallimastix sp. L2. A-D Bar = crometer h, hydrogenosomes r, ribosome globules (Munn et al. 1988). Asterisk, vesicular structures. From Voncken et al. 2002a, modified...

Davidson EA, van der Giezen M, Horner DS, Embley TM, Howe CJ (2002) An [Fe] hydrogenase from the anaerobic hydrogenosome-containing fungus Neocallimastix frontalis L2. Gene 296 45-52... 

Gelius-Dietrich G, Ter Braak M, Henze (2007) Mitochondrial steps of arginine biosynthesis are conserved in the hydrogenosomes of the chytridiomycete Neocallimastix frontalis. J Eukaryot Microbiol 54 42-44... 

Voncken F, Boxma B, Tjaden J, Akhmanova A, Huynen M, Verbeek F, Tielens AGM, Hafer-kamp I, Neuhaus HE, Vogels G, Veenhuis M, Hackstein JHP (2002a) Multiple origins of hydrogenosomes functional and phylogenetic evidence from the ADP/ATP carrier of the anaerobic chytrid Neocallimastix sp. Mol Microbiol 44 1441-1454... 

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