Inhibition and killing of fungi by the polyamine oxidase-polyamine system

Both components of the polyamine oxidase (PAO)-polyamine system are known to be present in phagocytes and have thus been postulated to contribute to the antimicrobial activity of these cells. Therefore, the effects of the PAO-polyamine system on three medically important opportunistic fungi were examined. Yeasts of Cryptococcus neoformans, but not Candida albicans blastoconidia or Aspergillus fumigatus conidia, were efficiently killed by the system. Two putative end products of the system, hydrogen peroxide and acrolein, both killed C. neoformans at concentrations attainable with the whole system. However, catalase failed to inhibit activity of the whole system, making hydrogen peroxide an unlikely mediator of killing. Although C. albicans blastoconidia and A. fumigatus conidia were not killed by the PAO-polyamine system, germ tube formation by the former, and hyphal growth by the latter, were markedly inhibited. These data establish that the PAO-polyamine system possesses antifungal activity.     

Electrophoretic protein patterns of Geotrichum and its teleomorphs

Total patterns of water-soluble proteins of 35 strains (7 species) of Galactomyces and Dipodascus strains with their respective Geotrichum anamorphs are compared. Quantitative differences among a number of species are found with iso-electric focusing; bands that characterize species are selected. Qualitative differences are found between the teleomorph genera.     

Vanillic acid metabolism by selected soft-rot,brown-rot,and white-rot fungi

Metabolism of vanillic acid, a product of lignin degradation, has been studied in selected representatives of soft-rot, brown-rot and white-rot fungi. All of the brown-and white-rot species examined decarboxylated vanillate to methoxyhydroquinone oxidatively. Mycelium extracts of all these fungi, except Pleurotus ostreatus contained high levels of an NAD(P)H-dependent vanillate hydroxylase. P. ostreatus also released ¹⁴CO₂ from ¹⁴COOH-vanillate but by a different mechanism possibly involving phenoloxidases. Most of these fungi also contained a dioxygenase which catalysed the intra-diol cleavage of hydroxyquinol (1,2,4-trihydroxybenzene) to form maleylacetate. No 3-O-demethylase activity was detected, and data indicate that in some of the fungi examined cleavage of the aromatic ring occurs without prior removal of the methoxyl group. None of the soft-rot fungi tested contained vanillate hydroxylase or hydroxyquinol 1,2-dioxygenase, but very low levels of protocatechuate 3,4-dioxygenase were detected in mycelium extracts. Vanillate catabolism among members of this group occurs via a different route which may involve ring demethylation although no 3-O-demethylase activity was detected in this study. The enzyme NAD(P)H-quinone oxidoreductase was demonstrated to exist in all the studied groups of fungi.     

Chemical regulators of carotenogenesis by Blakeslea trispora

The activation of the carotene biosynthetic pathway in Blakeslea trispora was found to occur by trisporic acid and many other compounds such as abscisic acid, β-ionone, α-ionone and vitamin A which share significant structural similarity with trisporic acid. The magnitude of stimulatory activities of these effectors was in the order trisporic acid > abscisic acid > β-ionone > α-ionone > vitamin A. Comparison of structures and stimulatory activities of all the effectors indicated that the short length of the side chain and the presence of a keto group in the ring structure of the trisporic acid molecule contributed significantly to the biological activity towards carotenogenesis.     

Endogenous respiration and regulation in a primitive marine fungus

The relationship between the respiration and the presence and utilization of endogenous and exogenous substrates was studied in the non-filamentous obligately marine fungus Thraustochytrium aureum. Using isotopic and manometric methods, it was shown that almost all exogenous glucose is assimilated, whilst almost all the oxygen consumption in the presence of exogenous glucose was due to oxidation of endogenous reserves. In contrast, exogenous glutamate, which cannot serve as the sole carbon source for growth, inhibits respiration of endogenous materials, and is itself rapidly oxidized. The uncoupler 2,4-dinitrophenol stimulates the oxidation of endogenous reserves without affecting the uptake and use of exogenous glucose. These data strongly support the idea of physiologic compartmentation in this organism.     

Effects of density on food utilization and surfacing behaviour in the obligatory air-breathing fish Channa striatus

Numbers of fungi were determined in water and sediment samples from a virgin salt-fresh water transect at North Point, James Bay. Fungal densities in the water samples showed an approximately linear increase from 28–70 CFU/100 ml, at the salt water extremity of the transect, to 13–16,000 CFU/100 ml at the freshwater extremity. Sediment fungal densities were also higher in the inland samples. There was no apparent difference between the numbers of fungi estimated using enumeration media prepared with distilled or saline water. Data are discussed in relation to the physical, chemical and organic status of the water, the nature of the surrounding vegetation and possible sources of the enumerated fungi.     

Präadaption bei Flechten iranischer Halbwüsten

25 species of lichens have been collected in semidesertic to desertic areas of Iran. On the basis of spatial relations to the substrate and anatomical features of the thallus three main groups (one with a subdivision based on colour and morphology of the thallus) can be differentiated. Selective advantages and peculiarities in connection with the desert habitat are pointed out, such as inverse thallus-structure, a dense network of skeletal hyphae in the substrate in otherwise epilithic species, proliferating areolae of the thallus, immersed pycnidia with trichogynes and brownish spores in groups with usually colourless spores. Most of the species are wide-spread in arid and often also in humid regions; only one species,Verrucaria buschirensis J. Steiner, seems to be endemic. The prevalence of cyanophilic lichens in deserts may have phylogenetic reasons, as these groups appear to date back to periods without higher vegetation and a desert-like environment.

Herrn Prof. Dr. L.Geitler zum 80. Geburtstag gewidmet.