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A fungal phylogeny based upon orotidine 5'-monophosphate decarboxylase.

Orotidine 5'-monophosphate decarboxylase protein sequences from 14 fungi, 1 slime mold, 2 mammals, and 3 bacteria are compared and aligned and shown to be homologous. Based on the optimal alignment of the fungal sequences, a phylogenetic tree is derived. Within the fungi, the fission yeast Schizosaccharomyces pombe shows a closer relationship to both basidiomycetes and phycomycetes than it does to orthodox ascomycetes (plectomycetes, pyrenomycetes, and budding yeasts). Intron conservation shows a close relationship between phycomycetes and basidiomycetes. The imperfect fungi Trichoderma and Cephalosporium are shown to be closely related to Neurospora. The predicted origin of the group of budding yeasts is dependent on the analytical method used.

Amino Acid Sequence↗

Counterimmunoelectrophoresis and opportunistic fungal infections.

Sera from 35 apparently normal humans, 37 compromised human patients, 30 hedgehogs and 30 sheep, were examined for precipitating antibodies to four opportunistic fungi - Absidia corymbifera, Aspergillus fumigatus, Candida albicans and Rhizopus arrhizus-using counterimmunoelectrophoresis (CIE). Precipitins to A. fumigatus were almost exclusively confined to specimens obtained from the compromised human group (51% of those examined) while Candida precipitating antibodies were detected in the sera of both normal (26%) and compromised (49%) humans and in 10% of the hedgehog specimens. Serum precipitins against the two phycomycetes included in the investigations were rare. Because of the complexity of most fungal antigen extracts, it appears the two phycomycetes included in the investigations were rare. Beause of the complexity of most fungal antigen extracts, it appears essential that sera be tested against a number of different antigen concentrations if CIE is to be used with confidence in fungal serology.

Antibodies, Fungal↗

Nosocomial infection by Rhizomucor pusillus in a clinical haematology unit.

Three patients suffering from acute leukaemia were treated with cytotoxic agents and broad-spectrum antibiotics and received blood transfusion and nasal packing for severe epistaxis. All developed necrosis of nasal and facial tissues, with facial swelling an oedema; two biopsies showed typical phycomycete mycelium, and Rhizomucor pusillus was grown from one biopsy. Air and surfaces in the unit and the air intake and ducting were all heavily colonized by Rh. pusillus and other phycomycetes. It is suggested that Rh. pusillus spores from the air invaded the tissues in the conditions promoted by the nasal packing in these patients with impaired defences.

Adult↗

Rumen anaerobic fungi of cattle and sheep.

Plant fragments obtained from natural rumen digesta of fistulated cattle and sheep were examined by scanning electron microscopy. Various plant materials suspended in the rumen for different times were examined likewise. By 2 h large numbers of phycomycetous fungal zoospores were found attached to fibrous plant fragments, particularly vascular tissues. The subsequent development of these fungi resulted in production of thalli with extensive rhizoids and with sporangia up to 175 mum long. Scanning electron microscope examination of plant fragments randomly selected from natural rumen contents of both cattle and sheep demonstrated widespread colonization by large populations of these anaerobic fungi. Furthermore, all plant fragments suspended in nylon bags in the rumen were also extensively colonized. These findings demonstrate that plant fragments in the rumen are the sites of colonization and development by the anaerobic phycomycetous fungi. In addition, the results suggest that these fungi may form a significant part of the rumen microbiota in cattle and sheep fed on fibrous diets and suggest that they may be important in fiber digestion.

Journal Article↗

Subcutaneous phycomycetosis.

A case is reported of a subcutaneous mycotic granuloma of the forearm in a young Sudanese child. It is thought that, despite the absence of culture studies, the characteristic morphology of the fungus and the histological findings permit not only the identification of the causative organism as a phycomycete, but also the realization that it belongs not to the family Mucoraceae but to one of the other families of the phycomycetes, viz., Entomophthoraceae or Mortierellaceae. At present the most commonly identified species has been Basidiobolus, of the family Entomophthoraceae. The findings in the present case are closely similar to those reported by Lie Kian Joe and Eng, Njo-Injo Tjoei (1960) in their paper ;Subcutaneous phycomycetosis: a new disease found in Indonesia'.

Child↗

Systemic fungal infections in cats.

Pneumonia and ileitis due to Aspergillus spp was diagnosed at necropsy in an adult female cat. In a 2nd cat, Aspergillus spp caused acute focal necrotizing pneumonia. A 3rd cat had severe necrotizing colitis caused by a phycomycete. Two of the cats had clinical signs and pathologic lesion compatible with feline panleukopenia, which probably increase their susceptiblity to fungal infection. The ability of Aspergillus spp and phycomycetes to invade tissue was probably enhance by prolonged treatment of the cats with antibiotics.

Animals↗

Zygomycosis presenting as nasal polyps in a healthy child.

A 15-year-old boy presented with unilateral nasal polyps. Pathological examination showed submucosal granulomas and fungal organisms with occasionally septate hyphae. These organisms were identified by the Centers for Disease Control, Atlanta, as being members of the class of fungi known as Zygomycetes (formerly Phycomycetes). Based on strong morphological and clinical criteria, we believe the causative organism to be Entomophthora coronata. The patient had no evidence of diabetes mellitus or compromised immunity. This patient represents an unusual case of nasal polyps caused by an organism that has rarely been diagnosed in North America.

Adolescent↗

Invasive primary cutaneous phycomycosis in diabetic leg ulcers.

Two cases of cutaneous phycomycosis in the form of diabetic leg ulcers were diagnosed by culture and biopsy demonstration of invasive fungal infection. The first patient had an infected vesicular skin lesion. Systemic amphotericin B therapy and repeated debridement were curative. A posttraumatic leg ulcer developed in the second patient in the setting of hyperglycemia and renal insufficiency. Aggressive infection necessitated a curative amputation. Phycomycetes can cause or complicate diabetic leg ulcers and such infections may require biopsy for early recognition and subsequent successful therapy.

Aged↗

Butyrivibrio spp. and other xylanolytic microorganisms from the rumen have cinnamoyl esterase activity.

High concentrations of hydroxycinnamic acids in the hemicellulosic fraction of dry season tropical grasses may influence the rate of microbial degradation of arabinoxylans by ruminant animals. The ability of 22 strains of Butyrivibrio fibrisolvens, other ruminal bacteria (Ruminococcus albus SY3, Ruminococcus flavefaciens RF1,Prevotella ruminicola AR20) and the ruminal phycomycete Neocallimastix patriciarum CX to digest the tropical grass Heteropogon contortus(spear grass) and hydrolyse esterified ferulic and p-coumaric acid was examined. Significant digestion (8-36%) of spear grass occurred with the B. fibrisolvens strains H17c, A38, LP92-1-1, 49,R. albus SY3 and N. patriciarum. Hydrolysis of ester-linked ferulic and p-coumaric acid occurred with all organisms except B. fibrisolvens strains GS113, OB156 and LP1028 and P. ruminicola AR20. The ratio of ferulic to p-coumaric acid hydrolysed by different strains of Butyrivibrio spp. varied markedly from 0.96 for AR 51 to 0.16 for A38. Butyrivibrios which were fibrolytic (H17c and A38) had higher extracellular cinnamoyl esterase activity than bacteria that did not digest spear grass fibre (LP 91-4-1 and AR 20) which had low activities or only produced cell associated enzyme. Cell associated and extracellular esterase activity were induced when Butyrivibrio spp. strains H17c, A38 and E14 and the Ruminococcus spp. were grown on birchwood xylan but induction did not occur to the same extent with N. patriciarum. This is the first reported observation of cinnamoyl esterase activity in the genus Ruminococcus. The fungus N. patriciarum had significantly higher digestibility of spear grass and solubilisation of phenolic acids than the bacteria. The study shows that high levels of extracellular cinnamoyl esterases are characteristic of a selection of fibre-degrading ruminal bacteria and fungi which probably indicates that these enzymes are common amongst xylanolytic ruminal microorganisms.

Journal Article↗

The distribution of the NADPH regenerating mannitol cycle among fungal species.

The mannitol cycle is an important NADPH regenerating system in Alternaria alternata. The cycle is built up to the following enzymes: mannitol 1-phosphate dehydrogenase, mannitol 1-phosphatase, mannitol dehydrogenase and hexokinase. The net reaction of one cycle turn is: NADH + NADP+ + ATP leads to NAD+ + NADPH + ADP + Pi. The enzymes needed for an operating cycle were found in Aspergillus, Botrytis, Penicillium, Pyricularia, Trichothecium, Cladosporium and Thermomyces all genera belonging to Fungi Imperfecti. The only genus of this class lacking the cycle was Candida. No genera from the classes Basidiomycetes and Phycomycetes showed any mannitol 1-phosphate dehydrogenase or mannitol 1-phosphatase activities. The genera investigated, belonging to Ascomycetes, Gibberella, Ceratocystis and Neurospora all lacked mannitol 1-phosphate dehydrogenase. It was concluded that the mannitol cycle is an important and widespread pathway for NADH oxidation and NADP+ reduction in the organisms belonging to the class Fungi Imperfecti.

Fungi↗

Effects of cations of the plasma membrane of Blastocladiella emersonii zoospores An ESR study.

The physical properties of the plasma membrane of the aquatic phycomycete Blastocladiella emersonii were investigated, in particular the effects of cations on membrane structure. Intact zoospores and lipid extracts were labelled with the spin-labels 5-nitroxystearate (5-NS), 12-nitroxystearate (12-NS), and 2,2,6,6-tetramethylpiperidine-1-oxyl (Tempo). Electron spin resonance spectroscopy indicated a total of three breaks in plots of the hyperfine splitting parameter, 2T parallel, order parameter, S, and the partition coefficient, f, vs. temperature. The first and third break points (TL and TH) were found to be independent of the external K+, Ca2+, or Mg2+ concentrations. They were similar to the break points found in aqueous dispersions of lipid extracts and correlate well with the temperature limits for zoospore liability. In contrast, the middle break point (TM) was markedly influenced by the external Ca2+ concentration. Ca2+ increased TM from 12 degrees C (no Ca2+ added) to 22 degrees C (10 mM Ca2+), i.e., growth temperature. K+ reversed this Ca2+ effect, downshifting TM from 22 degrees C to 10 degrees C. A comparison of the physico-chemical effects of these ions on the membrane, as revealed by the cation-induced shift in TM, is closely correlated with the temperature dependence and physiological effects of cations on zoospore differentiation. This suggest that cations may modify the physical state of the plasma membrane and be involved in regulating the initial changes during zoospore encystment.

Blastocladiella↗

Electron spin resonance study of the isolated lipid components from Blastocladiella emersonii zoospores.

The physico-chemical properties of lipid components isolated from zoospores of the aquatic phycomycete, Blastocladiella emersonii, were investigated with electron spin resonance (ESR) spectroscopy using the spin label, 5-nitroxystearate. Lipid dispersions were made from zoospore phospholipids and glycolipids, both singly and in combination with each other and with isolated neutral lipid components. Plots of the hyperfine splitting parameter (2T parallel) vs. temperature indicate that it is the zoospore glycolipids rather than the phospholipids which are responsible for the phase transformations previously observed in aqueous dispersions of the total lipids extracted from zoospores and in zoospores in vivo. The discontinuities observed in the glycolipid dispersions seem to represent the onset and completion of a gel-to-liquid-crystalline phase transition. Over the temperature range tested, Ca2+ increased the rigidity of the glycolipid dispersions, the major component of which is probably a diglucosyldiglyceride, but had no effect on the phospholipid dispersions. The increase in 2T parallel was not affected by inclusion of neutral lipids into the glycolipid dispersion but was eliminated at high (5 : 1, w/w) phospholipid-to-glycolipid ratios. The Ca2+ effect was relatively independent of both the absolute rigidity of the dispersion and its phase (gel or liquid-crystalline), suggesting an interaction with the glycolipid head group rather than the hydrocarbon core. The Ca2+-induced increase in 2T was neither prevented nor reversed by the presence of K+. The presence of two spin label populations co-existing in a dynamic equilibrium was found in glycolipid/neutral lipid dispersions. Plots of the percentage ([HA/(HA + HB)] X 100 of the spin label population, as measured by the peak height of the low-field peaks, corresponding to the more immobilized component (HA) vs. temperature indicated two break points. The temperatures at which these break points occurred are similar to those obtained for the glycolipid dispersions, and match the break points (TL and TH) found in ESR experiments using zoospores in vivo. The importance of the glycolipids in the development of this organism is discussed.

Blastocladiella↗

Systemic mycosis in Scottish red deer (Cervus elaphus).

The pathological features of 10 cases of systemic infection of young red deer by fungi morphologically identified as phycomycetes are described. The most frequently affected organs were the kidneys, followed by liver and central nervous system. The fungi stimulated an acute pyogenic inflammatory reaction and a phagocytic giant cell response. Vasculitis with thrombosis and spread of fungi to the surrounding tissue was a common finding. Culture was attempted in 4 cases; one yielded Absidia, 2 Aspergillus and the other an unidentified fungal growth. Analysis of the histories suggests that, in nine of the ten cases, stressful husbandry may have been a predisposing factor.

Abomasum↗