Geotrichum Species Research Articles

Hydrolysis of linalyl acetate and α-terpinyl acetate by yeasts

Of 104 yeasts tested for the hydrolysis of rac-linalyl acetate and rac-α-terpinyl acetate twelve hydrolysed rac-linalyl acetate. Five of these belonged to five different species of Geotrichum. The most promising strain, Geotrichum capitatum CBS 0572.82, yielded (S)-linalool in 56% enantiomeric excess after 6h (E value ∼5, c = 32%). Only one unclassified yeast isolate hydrolyzed rac-α-terpinyl acetate with a slight preference for the S-enantiomer (E value ∼2). © Rapid Science Ltd. 1998

Biological activity of cyclopaldic acid, a major toxin of Seiridium cupressi, its six derivatives, and iso-cyclopaldic acid.

Cyclopaldic acid (CA), its six derivatives, and iso-cyclopaldic acid (IsoCA) were assayed for toxicity to cuttings of three species of cypress, as well as to mung bean, oat, and tomato explants. Toxicity to host and non-host plants of CA derivatives having one or both of the aldehyde groups transformed was less than that of CA. Shoot tissues of Cupressus macrocarpa artificially infected by Seiridium cupressi leached electrolytes more than those of C. sempervirens and C. arizonica. CA, IsoCA, and to a lesser extent the monoacetylated, phenylhydrazone and hydrogenated derivatives of CA caused loss of electrolytes from cypress tissues. CA, IsoCA, and monoacetyl CA caused limited callus development of cypress tissues. Diacetylhydrazone CA enhanced the yield of cypress callus tissue. CA derivatives having both aldehyde groups modified induced root formation on cypress cuttings. The antifungal activity showed by CA toward species of Botrytis, Fusarium, and Geotrichum markedly decreased in its derivatives. The inhibitory effect of CA on esterases was exhibited also by IsoCA and the monoacetylated derivative.

Macrophage Response to Viruses, Protozoa, and Fungi: Secretory and Cellular Activities Induced in Resting Unprimed Bone Marrow-Derived Mononuclear Phagocytes

The secretory (tumor necrosis factor, TNF-α; nitrite) and cellular response (mitochondrial respiration, TNF-α-independent tumoricidal activity) of a pure, lymphocyte-free population of resting, unprimed rat bone marrow-derived mononuclear phagocytes (BMMø) to direct interaction with viruses, protozoa, and fungi was assessed and compared with that triggered by bacterial agents and interferon-γ (IFN-γ). Viruses (herpes simplex, vaccinia, poliomyelitis, vesicular stomatitis, lymphocytic choriomeningitis, Sendai), protozoa (Trypanosoma brucei, Giardia lamblia), and fungi (Penicillium, Trichosporon, Fusarium, Rhizopus, Aspergillus, Geotrichum species) affected primarily the secretion of TNF-α and mitochondrial respiration of BMMø; their effects on the secretion of nitrite and on tumoricidal activity were at best marginal. Collectively, the macrophage response to viruses, protozoa, and fungi was less varied and less marked than that to bacterial agents (intact organisms, peptidoglycan, lipoteichoic acid, lipopolysaccharide) and IFN-γ.

Partial purification and characterization of mold antigens commonly found in foods

Rapid methods are needed for detection of molds in foods; therefore, an enzyme-linked immunosorbent assay was developed. The extracellular and mycelial antigens for Mucor, Aspergillus, Cladosporium, and Geotrichum species were partially purified and characterized. The molecular masses of the mycelial and extracellular antigens, as determined by size exclusion chromatography, ranged from 4.5 x 10(5) to 6.7 x 10(5) Da. There was only one main antigenic peak separated by Sepharose CL-4B and concanavalin A-Sepharose columns for Mucor, Cladosporium, and Geotrichum mycelial and extracellular antigens, but there were two for Aspergillus mycelial antigens and three for Aspergillus extracellular antigens. These antigens contained 10 to 50% protein which was part of the active site since protease digestion significantly decreased antigenic activity. Neutral sugars, ranging from 13 to 75%, made up the rest of the active site, and < 1% phosphate was detected in mycelial antigens. Geotrichum, Cladosporium, and Aspergillus antigens contained mainly glucose, galactose, and mannose. Mucor antigens contained these sugars plus fucose. The percentage of sugars differed between the mycelia and extracellular antigens. Enzymatic digestion and competitive inhibition tests using different sugar derivatives showed that galactosyl residues with beta linkages were immunodominant for Aspergillus, Geotrichum, and Cladosporium antigens and mannosyl residues with alpha linkages were immunodominant for Mucor antigens.

From Candida to Torulopsis: Funguria in long-term stay patients under the pressure of fluconazole use

The API 20-C clinical yeast identification system (API Laboratory Products Ltd, St. Laurent, Quebec) has given routine clinical laboratories a means of readily discriminating among 15 species of Candida, many species of Cryptococcus, Geotrichum (a mould), Prototheca (an alga), Rhodotorula, Torulopsis, and Trichosporon that had not been previously available. It is to be expected that with the availability of this test, the microbiology laboratory would begin to identify these hitherto unfamiliar species. The unfamiliarity of the new name might well attract the clinicians' attention. We decided to look at the epidemiology of these yeasts in sputum and urine. For the yeast cultures of the first 3 months of 1992, there were 22 individuals with the isolation of Candida albicans from the urine and 10 from the sputum. For non-Candida albicans yeasts, there were 16 from urine (one C. parapsilosis, seven C. tropicalis, six Torulopsis glabrata, and two Trichosporon beigelii) and two from sputum (one C. parapsilosis and one C. tropicalis). Although yeasts other than C. albicans were seldom isolated from the sputum, it was also apparent on review of these cases that only onehalf of patients were admitted with yeasts other than C. albicans or, occasionally, C. tropicalis in the urine. Eight of the 16 patients with non-C. albicans yeasts in the urine on review were shown to have previously had a C. albicans isolated from the urine that had been treated with fluconazole before the appearance of the non-C, albicans isolate. Three-fourths of the patients with funguria had Foley catheters or suprapubic catheters, and the remainder had Texas (condom) catheters (two exceptions). Thus, canTable 1. Isolation of Yeast Species 1991 (as individuals) a

Oral Geotrichum candidum infection associated with HIV infection : A case report

Infections with Geotrichum species, although rare, are sometimes seen in immunocompromised hosts. We report a case of oral geotrichosis in a patient seropositive for human immunodeficiency virus who had erythematous mandibular and maxillary gingiva but was otherwise free of any active systemic disease. Geotrichum candidum was shown by both culture and histopathology to be present in the lesion and was deduced to be the causative organism. The patient responded well to several weeks of treatment involving oral topical administration of nystatin vaginal tablets.

Mycoflora and nutritional value of shelled melon seeds (Citrulus vulgaris Schrad.) in Nigeria

Thirteen fungi were isolated from mouldy shelled melon seeds. The fungi more frequently isolated included species of Mucor (11.25%), Rhizopus (13.75%), Aspergillus (36.25%), Macrophoma (2.50%), Penicillium (8.75%), Alternaria (5.00%), Fusarium (8.75%), Botrytis (6.25%), Torula (3.75%) and Geotrichum (3.75%). Healthy, shelled melon seeds inoculated with Fusarium solani for 7 or 14 days caused increases in the free fatty acid (f.f.a.) content of the healthy seeds from an initial value of 1.06% to 2.19% after 7 days and 4.23% after 14 days. Similar results were obtained when other fungal isolates were used as inocula but Fusarium solani effected the greatest increase in the f.f.a. content followed by Aspergillus niger and Penicillium notatum. The fungi also caused decreases in the crude protein from 35.51% to 25.16%, crude fibre from 4.30% to 1.35% and total carbohydrate content from 4.28% to 3.01% of the seeds after 14 days infection. Aflatoxin was detected (0.20 micron/g) in the infected seeds being sold in the markets and also from seeds inoculated with spores (0.40 micron/g) of A/ flavus and 0.50 micron/g) from a mixture of spores of various Aspergillus strains after incubation for 14 days.

Rapid identification of yeasts by semi-automated and conventional methods

Five different methods for the identification of significant yeast from clinical specimens were compared for their reliability, rapidity and cost-effectiveness. Three commercial methods consisted of semi-automated Abbott's yeasts identification system using MS-2 (Abbott Laboratories, Diagnostic Division, Irving, Texas), API 20C (Analytab Products, Inc., Plainview, NY) and Uni-Yeast-Tek (Flow Labs, Inc., MacLean, VA). Two conventional methods included the modified dye-plur plate auxanographic and rapid tube assimilation method. The 242 coded clinical isolates used in this study included 20 species of Candida, Cryptococcus, Saccharomyces Geotrichum, Rhodotorula, Torulopsis and Trichosporon. The identification accuracies with all the systems ranges between 92.3% to 97.5%. Results were available with Abbott's MS-2 within 24 h, with rapid tube assimilation method in 6-48 h and in 72 h with other systems. Rapid tube assimilation and dye-pour-plate auxanographic methods were least expensive, with labour and material costing around $1.00 per identification, whereas the commercial system cost a little over $5.00.

Use of the rapid diazonium blue B test to differentiate clinically important species of Trichosporon and Geotrichum.

Trichosporon isolates form pink to violet pigments following reaction with diazonium blue B which reliably differentiates them from Geotrichum species. The inoculum could be grown in static culture without diminishing the colour intensity. This modification facilitates use of the diazonium blue B reaction in clinical laboratories.

Inhibition of Mold Growth by Butylated Hydroxyanisole

Direct addition of 200 ppm of butylated hydroxyanisole (BHA) inhibited growth of some species of Penicillium, Aspergillus, or Geotrichum in a Glucose Salts Broth (GSB) and of A. flavus and P. expansum in Potato Dextrose Agar (PDA) or applesauce. In processed cheese spread direct addition of 400 ppm BHA was required to inhibit growth of A. flavus or P. expansum, whereas the concentration necessary for inhibition of A. flavus by a BHA emulsion sprayed on the surface was decreased to 150–200 ppm. BHA was effective in GSB over a wide range of pH values and incubation temperatures against A. flavus at a concentration of 200 ppm. The antimicrobial activity against A. flavus was slightly decreased by autoclaving and A. flavus slightly overcame BHA inhibition on extended incubation. Lipid depressed the antimicrobial activity of BHA against A. flavus in GSB or PDA. A combination of 150 ppm BHA plus 0.2% potasssium sorbate gave total inhibition of growth of A. flavus in GSB.

Evaluation of the new API 20C strip for yeast identification against a conventional method

The new API 20C yeast identification system together with appropriate microscopic morphology determinations achieved a 97% correlation with a rapid conventional method. Whereas a group composed of Candida, Torulopsis, Saccharomyces, and Rhodotorula was identified with ease (98% overall correlation), a second group, containing Cryptococcus, Trichosporon, and Geotrichum species, appeared to give the system the most difficulty (90% correlation). Within this group particular difficulty was encountered in identifying varieties of Cryptococcus albidus, C. terreus, C. laurentii, Trichosporon beigelli, and Geotrichum spp. as to species. The API 20C system should be incubated the full 72 h prescribed by the manufacturer. However, when used in conjunction with appropriate morphological tests, presumptive identifications of some Candida and Torulopsis species may be made at 24 to 48 h. To facilitate identifications of the more difficult group of yeasts, ancillary tests for determining nitrate reductase, urease, and phenol oxidase activities should be considered as additions to the strip. Incorporating the phenol oxidase test would be especially important for identification of Cryptococcus neoformans, a yeast which should be identified as quickly and as accurately as possible. The API 20C system with computer assistance has proved to be an easy-to-inoculate, versatile, and fairly rapid method of yeast identification, giving results comparable to those obtained by conventional methodologies.

New azasteroidal antifungal antibotics from Geotrichum flavo-brunneum. I. Discovery and fermentation studies.

Although Geotrichum species occur ubiquitously, antibiotic production by members of this genus has not previously been reported. The antibiotic complex designated A25822, consisting of one major and six minor structurally-related components active primarily against Candida and Trichophyton, represents a new family of naturally-occurring compounds. Approximately 90% of the antibiotic activity synthesized remained associated with the fungal cell mass, from which it was recovered by multiple methanolic extractions for quantitation. Antibiotic production was enhanced by tryptophan, iron, zinc, and high levels of dextrin.

Decryptification of acid phosphatase in arthrospores of Geotrichum species treated with dimethyl sulfoxide and acetone.

Decryptification of acid phosphatase in Geotrichum sp. arthrospores was accomplished using acetone or dimethyl sulfoxide treatment. Both dimethyl sulfoxide and acetone irreversibly destroyed the integrity of the spore membranes without solubilizing acid phosphatase.

Decryptification of Acid Phosphatase in Arthrospores of Geotrichum Species Treated with Dimethyl Sulfoxide and Acetone

Decryptification of acid phosphatase in Geotrichum sp. arthrospores was accomplished using acetone or dimethyl sulfoxide treatment. Both dimethyl sulfoxide and acetone irreversibly destroyed the integrity of the spore membranes without solubilizing acid phosphatase.

Degradation of DDT and DDE by Cheese Microorganisms

SUMMARY Representative microorganisms of the diverse flora associated with several varieties of surface‐ripened cheese were isolated. Species of streptococci, micrococci, yeasts and Gram‐positive rods accounted for most of the isolates. These were incubated at 32°C in media containing 0.5 ppm lindane, p‐p DDE, and p‐p DDT. The pesticides were dissolved in a small amount of ethanol to facilitate incorporation into the media. Following incubation for 10 days, the concentrations of residual pesticides were determined by electron capture gas chromatography. The growth of streptococci and micrococci isolates did not apear to produce any changes in pesticide levels, though they apparently were uninhibited by the pesticides. However, the growth of other isolates dechlorinated p‐p DDT. Moreover, aerobic growth of geotrichum species caused almost complete disappearance of the p‐p DDT and p‐p DDE peaks from the gas chromatograms. These results suggest the possibility that residues of DDT and DDE might be degraded if they are present in certain types of surface‐ripened cheeses.