Showing papers in "Mycopathologia in 1992"
TL;DR: It is concluded that the known naturally occurring levels of fumonisins present a potential threat to human and animal health and realistic tolerance levels need to be set.
Abstract: Contamination of corn with the fungus Fusarium moniliforme and its secondary metabolites, the fumonisins, has been associated with several human and animal diseases. This paper summarizes present knowledge and presents new data on the levels of fumonisins present in foods and feeds associated with these diseases as well as in commercial corn and corn-based products. The doses of fumonisins to which humans and animals consuming these products would be exposed are compared with those doses known to produce LEM in horses and hepatocarcinogenesis in rats. It is concluded that the known naturally occurring levels of fumonisins present a potential threat to human and animal health and realistic tolerance levels need to be set.
278 citations
TL;DR: Pulmonary edema and hydrothorax were observed in mature swine that died approximately 5 days after consuming corn screenings and induced in a pig that died after receiving 4 daily intravenous injections of fumonisin B1, a toxic metabolite produced by Fusarium moniliforme.
Abstract: Pulmonary edema and hydrothorax were observed in mature swine that died approximately 5 days after consuming corn screenings. These postmortem observations were reproduced in younger pigs that died within 1 week when fed the corn screenings under experimental conditions. Additionally, pulmonary edema and hydrothorax were induced in a pig that died after receiving 4 daily intravenous injections of fumonisin B1, a toxic metabolite produced by Fusarium moniliforme.
189 citations
TL;DR: The toxicity of fumonisins is characterized and it is hypothesized that altered sphingolipid metabolism causes hepatocellular damage resulting in release of membranous material into the circulation which ultimately results in pulmonary edema.
Abstract: Fumonisin B1 (FB1), a recently identified mycotoxin produced by Fusarium moniliforme in corn, has been shown to cause death in swine due to pulmonary edema, an apparently species specific effect, and to interfere with sphingolipid metabolism in vitro. Here we characterize the toxicity of fumonisins, using female cross-bred swine weighing 6 to 13 kg, and present a hypothesis regarding the mechanism of fumonisin-induced pulmonary edema in swine. FB1 was given daily intravenously (IV) to pig 1 for 9 days for a total of 72 mg (7.9 mg/kg) and to pig 2 for 4 days for a total of 67 mg (4.6 mg/kg). Pig 3 (control) was given saline IV for 9 days. Corn screenings naturally contaminated with FB1 (166 ppm) and FB2 (48 ppm) were fed to pigs 4, 5, and 6, and ground corn was fed to pigs 7 and 8 (controls). Pigs 4 and 7 were killed on day 5; pig 5 was found dead on day 6; and pigs 6 and 8 were killed on day 15. Pigs 4 and 5 had ingested 187 and 176 mg total fumonisins, respectively, while pig 6 had ingested 645 mg. Feed consumption had decreased in pigs fed corn screenings, with an additional sharp decrease prior to onset of clinical signs. Increases in serum liver enzymes, total bilirubin, and cholesterol were present, but electrocardiograms, heart rate, and body temperature were unaffected. Pigs dosed IV with FB1, developed mild intermittent respiratory abnormalities, while those fed screenings developed respiratory distress within 5 days. Mild interstitial pulmonary edema was observed in pig 1. Severe interstitial pulmonary edema, pleural effusion, and increased lung wet/dry weight ratio were observed in pigs 4 and 5. All pigs given fumonisin (either IV or orally) had hepatic changes characterized by hepatocyte disorganization and necrosis; pancreatic acinar cell degeneration was also observed. Ultrastructural changes in orally dosed swine included loss of sinusoidal hepatocyte microvilli; membranous material in hepatic sinusoids; and multilamellar bodies in hepatocytes, Kupffer cells, pancreatic acinar cells and pulmonary macrophages. Pulmonary intravascular macrophages (PIMs) contained large amounts of membranous material. Thus, the target organs of fumonisin in the pig are the lung, liver, and pancreas. At lower doses, slowly progressive hepatic disease is the most prominent feature, while at higher doses, acute pulmonary edema is superimposed on hepatic injury and may cause death. We hypothesize that altered sphingolipid metabolism causes hepatocellular damage resulting in release of membranous material into the circulation.(ABSTRACT TRUNCATED AT 400 WORDS)
186 citations
TL;DR: Fusarium moniliforme causes ear rot and stalk rot of corn and infection of corn kernels by this fungus is widespread and modes of infection as well as infestation of the kernel surface are important factors when considering the production of fumonisins in corn.
Abstract: Fusarium moniliforme is one of the most prevalent fungi associated with basic human and animal dietary samples such as corn. This fungus has been suspected of being involved in human and animal diseases since its original description. Fusarium moniliforme is in the section Liseola along with F. proliferatum, F. subglutinans, and F. anthophilum. Cultural mutation often occurs when F. moniliforme is grown on a medium rich in carbohydrates. Mutants may be either the mycelial or pionnotal type and often lose virulence and the ability to produce toxins. Toxins produced by F. moniliforme are fusaric acid, fusarins, gibberellins, moniliformin, and fumonisins. The fumonisins are produced most often when F. moniliforme grows on corn. Fusarium moniliforme causes ear rot and stalk rot of corn and infection of corn kernels by this fungus is widespread. Infection of developing corn kernels may occur through the silks, through holes and fissures in the pericarp or at points where the pericarp is torn by the emerging seedling, and as a result of systemic infection of the corn plant by F. moniliforme. These modes of infection as well as infestation of the kernel surface are important factors when considering the production of fumonisins in corn
185 citations
TL;DR: Reports here is a review of chemical and mycological data resulting from the study of several cases of PPE and ELEM.
Abstract: During the 1989 corn harvest season, numerous reports of equine leukoencephalomalacia (ELEM) outbreaks and a pulmonary edema (PPE) syndrome in swine from several regions of the United States were received by the National Veterinary Services Laboratories (NVSL), Ames, Iowa. Previous and concurrent research linked Fusarium moniliforme and fumonisin-contaminated feeds to both diseases. Chemical and mycological investigations revealed fumonisin B1 (FB1) concentrations of 20 to 360 ppm in suspect swine feeds and 8 to 117 ppm in suspect equine feeds. Nonproblem feeds contained concentrations below 8 ppm. Fusarium moniliforme and Fusarium proliferatum were isolated from both problem and nonproblem equine and swine feeds. When cultured on autoclaved corn, the F. moniliforme and F. proliferatum isolates produced respective FB1 and fumonisin B2 (FB2) that range from less than 5 to more than 2450 ppm and less than 5 to more than 1000 ppm, respectively. Isolates from both problem and nonproblem feeds produced high levels (greater than 500 ppm) in culture. Reported here is a review of chemical and mycological data resulting from the study of several cases of PPE and ELEM.
181 citations
TL;DR: The fumonisin B mycotoxins, although lacking mutagenicity in the Salmonella test or genotoxicity in the DNA repair assays in primary hepatocytes, appear to induce resistant hepatocytes similar to many known hepatocarcinogens.
Abstract: The fumonisin B mycotoxins (FB1 and FB2) have been purified and characterized from corn cultures of Fusarium moniliforme strain MRC 826. Fumonisin B1 (FB1, the major fumonisin produced in culture, has been shown to be responsible for the major toxicological effects of the fungus in rats, horses and pigs. Recent investigations on the purification of compounds with chromatographic characteristics similar to FB1 have led to the identification of two new fumonisins, FB3 and FB4. Fumonisins A1 and A2, the N-acetyl derivatives of FB1 and FB2 respectively, were also purified and shown to be secondary metabolites of the fungus. Short-term carcinogenesis studies in a rat liver bioassay indicated that over a period of 15 to 20 days, at dietary levels of 0.05–0.1%, FB2 and FB3 closely mimic the toxicological and cancer initiating activity of FB1 and thus could contribute to the toxicological effects of the fungus in animals. In contrast, no biological activity could be detected for FA1 under identical experimental conditions. These studies and others have indicated that the fumonisin B mycotoxins, although lacking mutagenicity in the Salmonella test or genotoxicity in the DNA repair assays in primary hepatocytes, appear to induce resistant hepatocytes similar to many known hepatocarcinogens.
164 citations
TL;DR: In this paper, the minimum toxic dose of fumonisins was evaluated by feeding ponies rations with known Fumonisin concentrations, and a panel of clinical chemistry parameters was evaluated twice weekly for both groups.
Abstract: An experiment to gain insight into the minimum toxic dose of fumonisins was conducted by feeding ponies rations with known fumonisin concentrations. Naturally contaminated corn screenings (CS) were blended with pellets, corn, and molasses to formulate individual daily diets. One group of 4 ponies was fed a ration with fumonisin B1 (FB1) varying from less than 1 ppm to 22 ppm. A second group of 5 ponies was fed a ration at varying rates containing 8 ppm FB1 for 180 days. A panel of clinical chemistry parameters was evaluated twice weekly for both groups. One pony in the first group died of equine leukoencephalomalacia (ELEM) after 225 days of which the final 55 days' diet contained 22 ppm FB1. Approximately 9 days prior to death, this animal experienced elevated liver chemistry values. All 5 ponies in the second group experienced mild, transient, clinical signs; were euthanized at 180 days; and had mild, histopathological brain lesions.
107 citations
TL;DR: The inhibition of de novo sphingolipid biosynthesis was specific, and appeared to be at the site of ceramide synthase, which catalyzes the formation of dihydroceramide or ceramide by the addition of the amide-linked fatty acid to sphinganine or sphingosine.
Abstract: The effects of fumonisins B1FB1, B2(FB{2}), and the backbone of fumonisin B1 remaining after hydrolysis of the tricarballylic groups with base (HFB1) on sphingolipid biosynthesis were studied in both primary rat hepatocytes and pig kidney epithelial cells (LLC-PK1). Fumonisins were potent inhibitors of sphingolipid biosynthesis in hepatocytes (IC50 of FB1=0.1 μM), but overt toxicity was not observed. In renal cells, fumonisins also inhibited sphingosine biosynthesis (IC50 for FB1=35 μM), and caused decreased cell proliferation as well. Higher doses (⩾70 μM) killed renal cells after exposure for 3 days. The inhibition of de novo sphingolipid biosynthesis was specific, and appeared to be at the site of ceramide synthase, which catalyzes the formation of dihydroceramide or ceramide by the addition of the amide-linked fatty acid to sphinganine or sphingosine. These results may account for the ability of fumonisins to cause equine leucoencephalomalacia and to promote tumor formation.
99 citations
TL;DR: Diversity of mitochondrial DNA (mtDNA) was investigated in 92 Trichophyton rubrum strains using endonucleases, and a phylogenetic tree was produced based on sequence divergence within mtDNA.
Abstract: Diversity of mitochondrial DNA (mtDNA) was investigated in 92 Trichophyton rubrum strains, 2 T. mentagrophytes var. mentagrophytes, 2 T. m. vor. interdigitale, 2 T. m. var. goetzii, 1 T. m. var. erinacei, 2 T. quinckeanum, 2 T. schoenleinii, 1 T. tonsurans, 2 T. verrucosum var. album, 2 T. v. var. discoides, 1 T. violaceum var. violaceum, 1 Arthroderma benhamiae, and 1 A. vanbreuseghemii using endonucleases, Hae III, Msp I, Hind III, Xba I, and Bgl II. Trichophyton species were divided into 7 groups, and a phylogenetic tree was produced based on sequence divergence within mtDNA. The following results were obtained: (1) T. rubrum was divided into 2 groups Type I and Type II, and was suggested to be a complex. (2) A. benhamiae was closely related to T. m. var. erinacei. (3) T. rubrum Type II, T. tonsurans, and A. vanbreuseghemii showed identical restriction profiles, and were suggested to be closely related to each other or identical. (4) T. quinckeanum and T. schoenlenii showed identical restriction profiles, which differed slightly from those of A. vanbreuseghemii. (5) mtDNA analysis was useful in identifying pleomorphic strains.
77 citations
TL;DR: The AAL toxins and the fumonisins (FB1 and FB2) are structurally related and produced respectively by Alternaria alternata f.sp.
Abstract: The AAL toxins and the fumonisins (FB1 and FB2) are structurally related and produced respectively by Alternaria alternata f.sp. lycopersici and Fusarium moniliforme. AAL toxin is characterized as a host-specific toxin, toxic to tomato, whereas fumonisin B1 causes equine leukoencephalomalacia. FB1 and FB2 were biologically active in susceptible tomato tissue (Earlypak-7) and animal tissue culture (rat hepatoma H4TG and dog kidney MDCK). Conversely, AAL toxin was also active in the rat and dog tissue culture cells. Both fungi produce toxin/s in culture that causes death in rats; these toxins are other than AAL and fumonisin. The peracetylated derivatives of AAL and FB1 are biologically inactive in both the tomato bioassay and the animal tissue culture systems. Acetylation of the amine renders AAL inactive. The hydrolysis product of AAL (phentolamine) is toxic to the susceptible tomato line whereas the phentolamine of fumonisin is not. AAL and FB1 can be analyzed by Continuous Flow Fast Atom Bombardment (CFFAB) and Ionspray Mass Spectrometry (ISM), both sensitive to the picomole range. The N-acetyl of the TFA hydrolysis product of AAL and FB1 is determined by comparing the fragment ions at m/z 86 and 140 for FB1 and 72 and 126 for AAL.
70 citations
TL;DR: Results confirm the involvement of cyclic AMP in the yeast-mycelium transition of C. albicans and confirm the role of theophylline and caffeine in the formation of germ tube and mycelium in yeast cells.
Abstract: A yeast-mycelium (Y-M) transition in Candida albicans was induced by exogenous yeast extract, adenosine, adenosine 5′-monophosphate (AMP), adenosine 5′-diphosphate (ADP), adenosine 3′∶5′ cyclic monophosphate (cAMP) and its analogue N6, O2′-dibutyryl adenosine 3′∶5′-cyclic monophosphate (dbcAMP) in defined liquid medium at 25°C. Adenosine 5′-triphosphate (ATP) was found to delay germ tube formation in yeast cells, whereas the cAMP phosphodiesterase inhibitors, theophylline and caffeine, induced a Y-M transition. Intracellular and extracellular cyclic AMP levels increased during the yeast-mycelium transition and maximum levels of intracellular cyclic AMP coincided with maximum germ tube formation. Of the many inducers and inhibitors of germ tube and mycelium formation in C. albicans tested, including incubation at 37°C or in the presence of 1.5mM CaCl2, the calmodulin inhibitor calmidazolium (R24571) added together with CaCl2 induced the highest intra- and extracellular cyclic AMP levels. These results confirm the involvement of cyclic AMP in the yeast-mycelium transition of C. albicans.
TL;DR: Fumonisins were readily produced in cultures of Fusarium moniliforme using a defined liquid medium and deuterium was shown to be incorporated exclusively in the methyl groups of the fumonisin backbone.
Abstract: Fumonisins were readily produced in cultures of Fusarium moniliforme using a defined liquid medium. Addition of 200 mg of d3-methyl L-methionine to 100-ml cultures of F. moniliforme gave increased overall yields and high levels of deuterium (2H) incorporation into fumonisin B1. Approximately 90% of the resulting fumonisin B1 contained 6 deuterium atoms, while 9% of the product contained 3 deuterium atoms. Deuterium was shown to be incorporated exclusively in the methyl groups of the fumonisin backbone. The addition of as little as 5 mg of labeled methionine stimulated fumonisin production, but only about 5% of the fumonisin produced contained 3 deuterium atoms.
TL;DR: A non-aromatic substance which previously has been revealed by us among prominent volatile compounds sampled from building materials from so-called ‘mould houses’ was produced only on water agar and was correlated with pungent odor in the cultures.
Abstract: Aspergillus versicolor, which has been isolated from several mould affected houses was shown by laboratory studies under axenic conditions to produce several specific volatile compounds on water agar. These compounds were not produced by the fungus when grown on a rich malt extract medium or on several synthetic media. The volatile compounds were analysed by GC-MS. The majority of the peaks represented aromatic compounds. A non-aromatic substance which previously has been revealed by us among prominent volatile compounds sampled from building materials from so-called ‘mould houses’ was produced only on water agar. According to a comparison with the mass spectrum and retention time of pure reference compound this compound is ethylhexanol, a compound not previously reported as a mould metabolite. The presence of this compound was correlated with pungent odor in the cultures.
TL;DR: It is concluded that the production of fumonisin B1 is a general characteristic of strains from the ‘A’ mating population of Gibberella fujikuroi associated with equine leukoencephalomalacia, since all 25 of the isolates that the authors examined were genetically distinct individuals.
Abstract: We examined 25 strains of Fusarium moniliforme from eight states known to be associated with equine leukoencephalomalacia, a disease caused by the mycotoxin fumonisin B1. We determined the mating population, mating type, and vegetative compatibility group to which each of these strains belonged. All 25 strains were in the ‘A’ mating population; 12 were A+ and 13 were A−. Seventeen of the 25 strains were female fertile; these strains also averaged higher levels of fumonisin B1 production than did the strains that were female sterile. Nitrate non-utilizing (nit) mutants were generated in all 25 strains and each strain was assigned to a unique vegetative compatibility group based on the inability of the derived nit mutants to form a prototrophic heterokaryon with complementary nit mutants derived from any of the other strains examined. From these data, we concluded that the production of fumonisin B1 is a general characteristic of strains from the ‘A’ mating population of Gibberella fujikuroi associated with equine leukoencephalomalacia, since all 25 of the isolates that we examined were genetically distinct individuals.
TL;DR: Liquid cultures of 200 Fusarium isolates selected to represent the most common species found in autumn pasture and in grain grown in New Zealand were analysed for trichothecenes and related compounds.
Abstract: Liquid cultures of 200 Fusarium isolates selected to represent the most common species found in autumn pasture (70 isolates) and in grain (130 isolates) grown in New Zealand were analysed for trichothecenes and related compounds. Production of butenolide, cyclonerodiol derivatives and culmorins was also measured. The principal trichothecenes produced were derivatives of either nivalenol (NIV), deoxynivalenol (DON) or scirpentriol (Sctol), in order of frequency. The principal trichothecene producing species were F. crookwellense, F. culmorum and F. graminearum. Isolates of the first two species were predominantly NIV-chemotypes with one or two isolates respectively as Sctol-chemotypes. F. graminearum showed equal quantities of NIV- and DON-chemotypes, with the DON-chemotypes producing primarily 15-acetyldeoxynivalenol (15-ADON).
TL;DR: Results indicate the pathogen and the AAL-toxin also can be recovered from ripe fruit with symptoms of the disease known as black mold, and evidence was obtained that the biosynthetic pathway for production of these toxins is present in several species of both Alternaria and Fusarium.
Abstract: The differential phytotoxicity of purified AAL-toxin to lines of tomato isogenic for the Asc gene parallels resistance to Alternaria alternata f.sp. lycopersici. This relationship, as reported earlier, is consistent with the role of AAL-toxin as a host-specific toxin with the role of a primary chemical determinant of Alternaria stem canker. Current results indicate the pathogen and the AAL-toxin also can be recovered from ripe fruit with symptoms of the disease known as black mold. Fumonisins are structurally similar to the AAL-toxins but are secreted by Fusarium moniliforme which is taxonomically distinct from A. alternata. F. moniliforme, is not pathogenic on living tomato tissues but was recovered from ripe tomato fruit with symptoms of black mold. The penetration of ripe fruit and subsequent colonization by both fungi appears to be saprophytic. Fumonisins and AAL-toxins express equivalent genotype-specific activity against the isogenic Asc lines of tomato and produce equivalent necrotic symptoms in tomato leaflet bioassays. Evidence was obtained that the biosynthetic pathway for production of these toxins is present in several species of both Alternaria and Fusarium. Toxin biosynthesis was sensitive to nutritional regulation in both genera. However, pathogenicity on tomato was not altered by the medium used for inoculum production in either genera and remained restricted to A. alternata f.sp. lycopersici in the studies reported here. Differences in the amount of toxin produced were found among isolates of both genera while the magnitude of the differences was defined by the substrate on which the fungi were grown.
TL;DR: Control of F. moniliforme in corn is therefore quite important, and one potential means to accomplish this reduction is biocontrol by the application of antagonistic rhizobacteria to corn kernels at planting.
Abstract: Fusarium moniliforme Sheldon is an economically important pathogen of corn (Zea mays L.) which causes stalk, root and ear rot. Several mycotoxins have also been isolated, identified and implicated in both animal and human toxicoses. The fungus can be disseminated in symptomless corn seed and can also survive in crop residues in the soil. Asymptomatic infection may be related to different corn cultivars, fungal strains, and environmental factors. Symptomatic expression of pathogenicity may vary, but usually the result of such infections is death of the plant. The greatest concern is the asymptomatic infection, since it is in this form that fungal toxins may surreptitiously enter animal and human food chains. F. moniliforme produces both fusaric acid, which is phytotoxic to corn and interferes with seed germination, and plant growth regulators that may affect pathogenicity of the fungus or be associated with the production of mycotoxins. Other metabolites, including fusarin C, moniliformin, and the fumonisins, may or may not be phytotoxic, but are associated with animal and human toxicoses. The control of F. moniliforme in corn is therefore quite important. One potential means to accomplish this reduction is biocontrol by the application of antagonistic rhizobacteria to corn kernels at planting. To be effective the bacteria must be able to colonize the corn root system and be able to prevent root infection by successful competing with F. moniliforme which may be accomplished by siderophore and or antibiotic activity.
TL;DR: A new fumonisin has been isolated from Fusarium moniliforme isolate MRC826 grown on corn and it was shown by NMR and mass spectrometry to be an isomer of fumonian B2 that has free hydroxyl groups at C-3 and C-10 instead of the normal C- 3 andC-5.
Abstract: A new fumonisin has been isolated from Fusarium moniliforme isolate MRC826 grown on corn. It was shown by NMR and mass spectrometry to be an isomer of fumonisin B2 that has free hydroxyl groups at C-3 and C-10 instead of the normal C-3 and C-5. This new fumonisin was detected in cultures of most isolates of F. moniliforme that were examined and was usually present at concentrations similar to those of fumonisin B2. Two isolates of F. moniliforme that produce significantly higher levels of this new isomer were identified.
TL;DR: Delayed hypersensitivity and lymphocyte transformation tests showed that the cellular immune response was depressed between the 4th and 6th week of infection when the animals were challenged with the soluble fungal antigen, which frequently indicates worsening of the disease, with greater involvement of the host.
Abstract: Sporothrix schenckii is the etiologic agent of sporotrichosis, a mycosis of world-wide distribution more commonly occurring in tropical regions. The immunological mechanisms involved in the prevention and control of sporotrichosis are not fully understood but apparently include both the humoral and cellular responses. In the present investigation, cellular immunity was evaluated by in vivo and in vitro tests in mice infected with yeast-like forms of S. schenckii. The disease developed systemically and cellular immunity was evaluated for a period of 10 weeks. The soluble antigen utilized in the tests was prepared from yeast form of the fungus through the sonication (20 min: 10 sonications at 50 W at 2-min intervals). Delayed hypersensitivity and lymphocyte transformation tests showed that the cellular immune response was depressed between the 4th and 6th week of infection when the animals were challenged with the soluble fungal antigen. This depression frequently indicates worsening of the disease, with greater involvement of the host. This is a promising field of research for a better understanding of the pathogeny of this mycosis.
TL;DR: In this paper, a study of the clinical isolates of Cryptococcus neoformans from 83 Brazilian patients with disseminated cryptococcosis showed that 75 were C neo-formans var gattii and 8 were var Gattii; the correlation of the varieties of C neo formans with the presence or not of hosts predisposing conditions to the mycosis was found.
Abstract: The study of the clinical isolates of Cryptococcus neoformans from 83 Brazilian patients with disseminated cryptococcosis showed that 75 were C neoformans var neoformans and 8 were var gattii Twenty-seven isolates were serotyped; all 19 var neoformans were serotype A and all 8 var gattii were serotype B The correlation of the varieties of C neoformans with the presence or not of hosts predisposing conditions to the mycosis showed that: (1) cryptococcosis caused by gattii variety occurred in 7 (583%) of the 12 nonimmunosuppressed patients, and (2) cryptococcosis caused by neoformans variety occurred in 65 (985%) of the 66 AIDS patients and in all 5 patients with other immunosuppressive conditions The comparison of the distribution of the gattii and neoformans varieties between the nonimmunosup-pressed and immunosuppressed patients showed a significant statistical difference (p < 001)
TL;DR: Immunotherapy using SCAV can be used as the vaccine of choice in early cases of equine cutaneous pythiosis insidiosi, as it maintained its ability to cure horses even after 18 months.
Abstract: Two vaccines to treat pythiosis insidiosi in horses were evaluated in 71 Costa Rican horses between 1982 to 1988. One vaccine used a cell-mass (CMV) as antigen and the other a soluble concentrated antigen (SCAV). Both vaccines cured horses infected with Pythium insidiosum (p value ∼ 14%). The age of lesions prior to vaccination was important in the response of the horses to immunotherapy. All horses with lesions 0.5 months or less in duration were cured regardless of the vaccine used. Horses with lesions two or more months old did not respond to either vaccine. The age of the horses did not have any influence on their response to the vaccinations. The CMV produced a prominent inflammatory reaction at the side of injection, while the SCAV gave a low inflammatory reaction. In addition, the CMV lost its effectiveness two to three weeks after its preparation. By contrast, the SCAV maintained its ability to cure horses even after 18 months. Immunotherapy using SCAV can thus be used as the vaccine of choice in early cases of equine cutaneous pythiosis insidiosi.
TL;DR: Naturally contaminated corn implicated in an outbreak of equine leukoencephalomalacia in southeastern Arizona was analyzed for mutagenic potential using the Salmonella/microsome mutagenicity assay before and after treatment with the ammonia procedure, and fumonisin B1 levels were reduced via the ammonia decontamination process.
Abstract: Naturally contaminated corn implicated in an outbreak of equine leukoencephalomalacia (ELEM) in southeastern Arizona was analyzed for mutagenic potential using the Salmonella/microsome mutagenicity assay before and after treatment with the ammonia procedure. Crude acetonitrile: water (1+1) extracts of high-pressure/ambient temperature (HP/AT) ammonia decontaminated, HP/AT plus low pressure/high temperature (LP/HT), and non-ammoniated fumonisin contaminated corn were tested for mutagenic potentials. Relatively pure (approx. 90%) fumonisin B1 standard was also tested for comparison purposes. The results of this experiment indicate that there was no mutagenic potential for the fumonisin B1 standard at the concentrations tested (100 μg/plate). Also, neither the naturally-contaminated corn nor the ammonia decontaminated samples elicited a positive mutagenic response. Fumonisin B1 levels, as determined by HPLC methods, were reduced by an average of 79% via the ammonia decontamination process. It is encouraging to note that, while further work is necessary to increase the efficacy of the ammonia process to reduce fumonisin levels, the ammonia process did reduce fumonisin levels and no mutagenic potentials were apparent in the treated corn.
TL;DR: Moniliformin was the least phytotoxic to L. minor, with only a 16% suppression of growth rate and a 54% reduction in chlorophyll at 66.7 μg/ml.
Abstract: Phytotoxicity and inhibitory effects of the fusarial toxins fumonisin B1 (FB1) [m.p. 103–105 °C], fusaric acid [m.p. 106–107 °C], butenolide (4-acetamido-4-hydroxy-2-butenoic acid lactone) [116–117 °C], 9, 10-dihydroxyfusaric acid [m.p. 150–155 ° C], and moniliformin on chlorophyll synthesis in the aquatic macrophyte Lemna minor (duckweed) were examined. FB1 proved to be most active, reducing the growth of L. minor fronds and their ability to synthesize chlorophyll by 53% and 59%, respectively, at 0.7 μg/ml. The growth rate of L. minor was reduced 59% by 6.7 μg/ml fusaric acid, 62% by 66.7 μg/ml butenolide, and 22% by 66.7 μg/ml 9,10-dihydroxyfusaric acid. Moniliformin was the least phytotoxic to L. minor, with only a 16% suppression of growth rate and a 54% reduction in chlorophyll at 66.7 μg/ml.
TL;DR: Ulastructural examination revealed that the propranolol-induced sclerotic cells were very similar to those observed in infected tissues, and this drug in the BF medium induced formation of sclerotics cells.
Abstract: The influence of growth conditions, as well as of propranolol on Fonsecaea pedrosoi morphogenesis was established using the chemically defined media of Czapeck-Dox (CD) and Butterfield (BF). Mycelial growth of F. pedrosoi in both media was obtained at room temperature (25 °C) for 14 days, without shaking, whereas conidia formed at 37 °C, for 4 days, in shaken cultures and could be isolated free from the mycelium by filtration in gauze. At low pH (2.5–3.0), there appeared sclerotic cells attached to normal hyphae. When propranolol was added to the CD medium moniliform hyphae were observed, whereas this drug in the BF medium induced formation of sclerotic cells. Ultrastructural examination revealed that the propranolol-induced sclerotic cells were very similar to those observed in infected tissues.
TL;DR: Keratin utilization commenced before the detection of significant extracellular keratinase activity which was always associated with mycelial growth and was not repressed by supplementation of keratin-containing medium with glucose, ammonium or sulfate.
Abstract: Chrysosporium queenslandicum, Graphium penicilloideus andScopulariopsis brevicaulis were grown on various supplemented basal salts media to compare keratinase induction, activity and repression. All three fungi can utilize keratin as a sole source of carbon, nitrogen and sulfur. Total keratinase activity inC. queenslandicum andS. brevicaulis, was not repressed by supplementation of keratin-containing medium with glucose, ammonium or sulfate. The production of keratinase activity was not derepressible in keratin-free media. Keratin utilization commenced before the detection of significant extracellular keratinase activity which was always associated with mycelial growth.
TL;DR: Ammoniation was ineffective for detoxification of the CM and produced hepatotoxicity in mice similar to that found in CM-fed rats, Thus, mice may be useful for investigations of F. moniliforme-induced hepatot toxicity.
Abstract: The fungus Fusarium moniliforme is ubiquitous on corn throughout the world and is a likely co-contaminant on corn infested with aflatoxin-producing Aspergillus flavus. Ammoniation has been used to detoxify aflatoxin-contaminated commodities. To determine the effect of ammoniation on the toxic potential of Fusarium moniliforme, male Sprague-Dawley rats were fed either diets containing 10% sound corn, ammoniated corn, corn culture material of hepatotoxic F. moniliforme strain MRC 826 (CM), or ammoniated CM for four weeks. They were observed for signs of toxicity and hematological, serum chemical and histopathological evaluations were made. Groups of male Balb/c mice were fed diets fortifies with 10% sound corn or CM for four weeks and evaluated by serum chemical and histopathological means to determine the suitability of mice as a model species for investigation of F. moniliforme-induced hepatotoxicity. Ammoniation was ineffective for detoxification of the CM. Hepatotoxicity and renal toxicity of CM and ammoniated CM were qualitatively similar, although renal tubular lesions appeared more advanced in rats fed ammoniated CM. Adrenal cortical cellular vacuolation was also found in CM and ammoniated CM-fed rats, while focal seminiferous tubular degeneration and aspermia were found only in the testes of ammoniated CM-fed rats. Fumonisin B1 concentrations of the CM and ammoniated CM diets averaged 99 and 75 ppm, respectively. CM containing 99 ppm fumonisin B1 also produced hepatotoxicity in mice similar to that found in CM-fed rats. Thus, mice may be useful for investigations of F. moniliforme-induced hepatotoxicity.
TL;DR: Data are presented on 39270 cultures taken over a 44 year span (1944–1988) at the University of Chicago's Dermatology Clinic, finding that Trichophyton rubrum became and remains the dominant dermatophyte at the present time.
Abstract: Data are presented on 39270 cultures taken over a 44 year span (1944–1988) at the University of Chicago's Dermatology Clinic In the mid 1940's Microsporum audouinii accounted for 60–80% of isolates It gradually decreased over the next two decades and disappeared altogether in the 1970's Trichophyton rubrum, rare in the 1940's accounted for over 60% of isolates in the mid-1960's only to be overtaken by T tonsurans This species, not isolated till the mid 1950's, became and remains the dominant dermatophyte at the present time Both T mentagrophytes and Epidermophyton floccosum increased in the 1970's and decreased later Unusual circumstances resulted in clusters of T verrucosum, T terrestre, and T schoenleinii isolates Infections were associated with rural dairy workers, zoo handlers and immigrant families respectively M canis and M gypseum were steady at a low rate throughout the entire period Rare isolates included M cookei, M persicolor, M racemosum, T simii, T soudanense, T violaceum, and the soil keratinophile, Aphanoascus fulvescens
TL;DR: The phylogenetic relationship of the genera Arthroderma and Nannizzia, was investigated by mitochondrial DNA analysis based on the restriction-fragment-length polymorphisms and showed no definite distinctions between the generas.
Abstract: The phylogenetic relationship of the genera Arthroderma and Nannizzia, was investigated by mitochondrial DNA analysis based on the restriction-fragment-length polymorphisms. Phylogenetic trees made on ten species. A. benhamiae, A. insingulare, A. quadrifidum, A. simii, A. vanbreuseghemii, N. fulva, N. grubyia, N. gypsea, N. incurvata and N. otae showed no definite distinctions between the genera Arthroderma and Nannizzia. These results support the conclusion of Weitzman et al. that the genera Arthroderma and Nannizzia are congeneric.
TL;DR: Two extracellular keratinases of Scopulariopsis brevicaulis were purified and partially characterized and were inhibited by phenylmethylsulfonyl fluoride which suggests a serine residue at or near an active site.
Abstract: Two extracellular keratinases of Scopulariopsis brevicaulis were purified and partially characterized. The enzymes were isolated by the techniques of gel filtration chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). These keratinases (K I & K II) were purified approximately 33 and 29 fold, respectively. SDS-PAGE of the products of gel filtration chromatography (K I & II) produced only one band each, suggesting homogeneity. The optimum pH for both keratinases was 7.8, while the optimum temperatures were 40 degrees C (K I) and 35 degrees C (K II). Estimated molecular weights were 40-45 KDa and 24-29 KDa for K I & K II respectively. Both keratinases were inhibited by phenylmethylsulfonyl fluoride which suggests a serine residue at or near an active site.
TL;DR: Results suggest that microbicidal activity inhibition by deoxynivalenol did not depend on non-oxidative pathway (phagosome-lysosome fusion) impairment, and indicate that the inhibition of killing mechanism arise from both oxidative and non-Oxidative pathways.
Abstract: Diacetoxyscirpenol and deoxynivalenol, two trichothecene mycotoxins shown previously to exert immunosuppressive effects on the immune system were examined for their in vitro effects on some functions of murine peritoneal macrophages. The cells were pre-incubated for 4 hr with the mycotoxin concentrations of 0.1 ng/ml–1 μg/ml. At concentrations that did not affect the cell viability (Specific Lactate Dehydrogenase test), diacetoxyscirpenol and deoxynivalenol suppress microbicidal activity of phagocytic cells. The diacetoxyscirpenol concentrations, which reduce phagocytosis (2ng/ml), microbicidal activity (1 ng/ml), superoxide anion production (1 ng/ml) and phagosome-lysosome fusion (0.1 ng/ml), indicate that the inhibition of killing mechanism arise from both oxidative and non-oxidative pathways. Phagocytosis, microbicidal activity and superoxide anion production are inhibited by deoxynivalenol at 1 ng/ml whereas phagosome-lysosome fusion is reduce above 100 ng/ml. These results suggest that microbicidal activity inhibition by deoxynivalenol did not depend on non-oxidative pathway (phagosome-lysosome fusion) impairment.