PR toxin

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 10(SRC), determined from a structure estimation method(2), indicates that PR-Toxin is expected to have very high mobility in soil(SRC). Volatilization of PR-Toxin from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 6.3X10-14 atm-cu m/mole(SRC), using a fragment constant estimation method(3). PR-Toxin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.3X10-27 mm Hg at 25 °C(SRC), determined from a fragment constant method(4).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 10(SRC), determined from a structure estimation method(2), indicates that PR-Toxin is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 6.3X10-14 atm-cu m/mole(SRC), developed using a fragment constant estimation method(3). According to a classification scheme(4), an estimated BCF of 3(SRC), from an estimated log Kow of 1.41(2) and a regression-derived equation(2), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation data in water were not available(SRC, 2013).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), PR-Toxin, which has an estimated vapor pressure of 3.3X10-27 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase PR-Toxin may be removed from the air by wet and dry deposition(SRC). PR-Toxin does not contain chromophores that absorb at wavelengths >290 nm(3) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

High quality local varieties of blue-veined cheese are made in the villages of the valleys of Cabrales, Valdeon and Bejes-Tresviso in North Spain. Penicillium roqueforti strains have been isolated from each of those blue cheeses and compared with the collection strain P. roqueforti CECT 2905 (ATCC 10110) and a strain 'Valdeon-industrial' used for large scale production of Valdeon cheese. Using molecular genetics techniques and 5.8S and 18S rRNAs and the D1-D2 regions of 28S rRNA all strains were identified as authentic P. roqueforti. These strains from local varieties of blue cheese could be distinguished from the Valdeon-industrial strain and the control strain CECT 2905 by the mitochondrial DNA restriction pattern. The industrial strain showed high levels of aspartylprotease AspA, whereas the culture collection strain showed barely detectable levels of this enzyme, as shown by proteolysis tests and by immunodetection with anti-AspA antibodies. The lipolytic activity was similar in the strains isolated from the three types of local blue cheeses. The strains isolated from the local varieties of the blue cheese produced moderate levels of PR toxin, whereas the Valdeon-industrial strains showed a higher content of this mycotoxin. All strains (except the control strain CECT 2905) showed similar levels of roquefortine C. The antitumoral compound andrastin A was produced by all strains at different levels. P. roqueforti CECT 2905 showed high ability to synthesize this compound. Andrastin A was present in all industrial and local varieties of blue cheese. The content of andrastin A was similar to that of other well-known blue cheeses from France and Denmark.

Penicillium roqueforti, Penicillium paneum, Monascus ruber, Alternaria tenuissima, Fusarium graminearum, Fusarium avenaceum, Byssochlamys nivea and Aspergillus fumigatus have previously been identified as major fungal contaminants of Danish maize silage. In the present study their metabolite production and in vitro cytotoxicity have been determined for fungal agar and silage extracts. All 8 fungal species significantly affected Caco-2 cell viability in the resazurin assay, with large variations for each species and growth medium. The 50% inhibition concentrations (IC(50)) of the major P. roqueforti metabolites roquefortine C (48 ug/mL), andrastin A (>50 ug/mL), mycophenolic acid (>100 ug/mL) and 1-hydroxyeremophil-7(11),9(10)-dien-8-one (>280 ug/mL) were high. Fractionating of agar extracts identified PR-toxin as an important cytotoxic P. roqueforti metabolite, also detectable in maize silage. The strongly cytotoxic B. nivea and P. paneum agar extracts contained patulin above the IC(50) of 0.6 ug/mL, however inoculated onto maize silage B. nivea and P. paneum did not produce patulin (>371 ug/kg). Still B. nivea infected maize silage containing mycophenolic acid (approx 50 mg/kg), byssochlamic acid and other metabolites, was cytotoxic. In contrast hot-spots of P. roqueforti, P. paneum, M. ruber and A. fumigatus were not more cytotoxic than uninoculated silage.

The composition of low-molecular biologically active metabolites typical of microscopic fungi has been studied in blastemas of fruticose lichens of the genera Cladonia, Cetraria, Evernia, Bryoria, and Usnes. The enzyme immunoassay method showed the presence of sterigmatocystin, emodin, mycophenolic acid, citrinin, alternariol, and diacetoxyscirpenol, which occurred regularly and, in most cases, at a frequency of 55 to 100%. The highest levels of accumulation were 0.001-0.003% for emodin, 0.0002% for alternariol and citrinin, 0.0001% for sterigmatocystin and mycophenolic acid, and 0.00005% of the weight of air-dry material for diacetoxyscirpenol. Other metabolites (cyclopiazonic acid, ergot alkaloids, ochratoxin A, PR toxin, deoxynivalenol, zearalenone, and fumonisins) were detected in these lichens less frequently (sometimes only upon the expansion of the territory of sampling), and their content was no more than 0.00005%. The peculiarities of the component composition and the levels of accumulation of fungal metabolites in lichens of different taxonomic affiliation were discussed.

Using a structure estimation method based on molecular connectivity indices(1), the Koc of PR-Toxin can be estimated to be 10(SRC). According to a classification scheme(2), this estimated Koc value suggests that PR-Toxin is expected to have very high mobility in soil.

PR toxin is a mycotoxin synthesized by Penicillium roqueforti(1,2). Many of the strains of P. roqueforti isolated from commercial blue cheeses as well as from moldy grains and nuts include isofumigaclavin C, penicilllic acid, patulin, botyodiploidin, and roquefortine(2).

/CASE REPORTS/ A patient employed in a plant where blue cheese was manufactured developed hypersensitivity pneumonitis to Penicillium roqueforti. Symptoms of cough, dyspnea, and malaise, and findings of bibasilar crackles, reduced lung volumes, hypoxemia, and bilateral infiltrates on chest roentgenogram, resolved after she left the workplace. Bronchoalveolar lavage revealed a high percentage of lymphocytes. Antibody to P. roqueforti was demonstrated in serum and lavage fluid. To /the authors'/ knowledge this case represents a new occurrence of hypersensitivity lung disease in the cheese manufacturing industry in the United States. /Penicillium roqueforti/

/ALTERNATIVE and IN VITRO TESTS/ Penicillium roqueforti, Penicillium paneum, Monascus ruber, Alternaria tenuissima, Fusarium graminearum, Fusarium avenaceum, Byssochlamys nivea and Aspergillus fumigatus have previously been identified as major fungal contaminants of Danish maize silage. In the present study their metabolite production and in vitro cytotoxicity have been determined for fungal agar and silage extracts. All 8 fungal species significantly affected Caco-2 cell viability in the resazurin assay, with large variations for each species and growth medium. The 50% inhibition concentrations (IC(50)) of the major P. roqueforti metabolites roquefortine C (48 ug/mL), andrastin A (>50 ug/mL), mycophenolic acid (>100 ug/mL) and 1-hydroxyeremophil-7(11),9(10)-dien-8-one (>280 ug/mL) were high. Fractionating of agar extracts identified PR-toxin as an important cytotoxic P. roqueforti metabolite, also detectable in maize silage. The strongly cytotoxic B. nivea and P. paneum agar extracts contained patulin above the IC(50) of 0.6 ug/mL, however inoculated onto maize silage B. nivea and P. paneum did not produce patulin (>371 ug/kg). Still B. nivea infected maize silage containing mycophenolic acid (about 50 mg/kg), byssochlamic acid and other metabolites, was cytotoxic. In contrast hot-spots of P. roqueforti, P. paneum, M. ruber and A. fumigatus were not more cytotoxic than uninoculated silage.

/OTHER TOXICITY INFORMATION/ High quality local varieties of blue-veined cheese are made in the villages of the valleys of Cabrales, Valdeon and Bejes-Tresviso in North Spain. Penicillium roqueforti strains have been isolated from each of those blue cheeses and compared with the collection strain P. roqueforti CECT 2905 (ATCC 10110) and a strain 'Valdeon-industrial' used for large scale production of Valdeon cheese. Using molecular genetics techniques and 5.8S and 18S rRNAs and the D1-D2 regions of 28S rRNA all strains were identified as authentic P. roqueforti. These strains from local varieties of blue cheese could be distinguished from the Valdeon-industrial strain and the control strain CECT 2905 by the mitochondrial DNA restriction pattern. The industrial strain showed high levels of aspartylprotease AspA, whereas the culture collection strain showed barely detectable levels of this enzyme, as shown by proteolysis tests and by immunodetection with anti-AspA antibodies. The lipolytic activity was similar in the strains isolated from the three types of local blue cheeses. The strains isolated from the local varieties of the blue cheese produced moderate levels of PR toxin, whereas the Valdeon-industrial strains showed a higher content of this mycotoxin. All strains (except the control strain CECT 2905) showed similar levels of roquefortine C. The antitumoral compound andrastin A was produced by all strains at different levels. P. roqueforti CECT 2905 showed high ability to synthesize this compound. Andrastin A was present in all industrial and local varieties of blue cheese. The content of andrastin A was similar to that of other well-known blue cheeses from France and Denmark.

An estimated BCF of 3 was calculated in fish for PR-Toxin(SRC), using an estimated log Kow of 1.41(1) and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for PR-Toxin is estimated as 6.3X10-14 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that PR-Toxin is expected to be essentially nonvolatile from water or soil surfaces(2). PR-Toxin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.3X10-27 mm Hg(SRC), determined from a fragment constant method(3).

/LABORATORY ANIMALS: Acute Exposure/ The acute toxicities of PR toxin and roquefortine ... were determined in both sexes of 2 strains of mice following iv administration. PR toxin was more toxic than roquefortine. Histological findings in animals treated with PR toxin consisted primarily of interstitial edema in the lung. Since PR toxin reacts with ammonia and free amino acids, substances present in high concentrations in blue cheese, PR imine and the reaction products formed by mixing PR toxin with L-alpha-alanine or L-leucine were tested. The acute i.p. toxicities of the PR analogs were considerably lower than that of the parent compound.

/LABORATORY ANIMALS: Acute Exposure/ The toxic effects of PR toxin were observed in mice, rats, and anesthetized cats. In mice and rats the toxic effects included abdominal writhing, decrease of motor activity and respiratory rate, weakness of hindleg and ataxia. In mice, the i.p. LD50 was 5.8 mg/kg. In mice, rats and cats PR toxin given i.p. caused ascites fluid and edema in the scrotum and lungs, and i.v. injection caused edema in the lungs, giving rise to a large volume of pleural and pericardial fluid. In rats, at the LD50 dose level (11.6 mg/kg, i.p. and 8.2 mg/kg, i.v.), the water content in the lungs was increased, but in the skin it was decreased. Blood K+, hematocrit, red blood cell, white blood cell, hemoglobin, uric acid, cholesterol, blood urea nitrogen and alkaline phosphatase concentrations were all increased, while the total protein and albumin contents were decreased after i.p. injection of PR toxin. High content of protein was found in the pleural fluid and fluid due to ascites. In anesthetized cats the blood pressure and respiratory rate were progressively decreased and the heart rate was reflexly increased after i.p. injection. The i.v. injection produced a multiple response on the arterial blood pressure, but with a progressively decreasing heart rate. Arrhythmias were observed in the late shock stage in the case of i.p. or i.v. injection. /The authors/ conclude that PR toxin produced acute toxic effects in animals via an increase of capillary permeability and a direct damage to the lungs, heart, liver and kidney.

/LABORATORY ANIMALS: Acute Exposure/ After 10-15 minutes, all weanling rats injected ip with 1.5 mg PR toxin developed breathing problems, motor incoordination and flaccid paralysis, particularly in the back legs. Death ensued in 24 hours. Histological tests showed turbid swelling of hepatocyte cytoplasm. Intraperitoneal LD50 was 14.5 mg/kg body weight.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Rats administered 0.5 mg PR toxin orally procapite/prodic for two months showed no visible effect.

For more Non-Human Toxicity Excerpts (Complete) data for PR-TOXIN (17 total), please visit the HSDB record page.

A base-catalyzed second-order hydrolysis rate constant of 2.8X10-3 L/mole-sec(SRC) was estimated using a structure estimation method(1); this corresponds to half-lives of 780 and 78 years at pH values of 7 and 8, respectively(1). PR-Toxin is expected to undergo hydrolysis in the environment due to the prescence of functional groups that hydrolyze under environmental conditions(2). PR-Toxin does not contain chromophores that absorb at wavelengths >290 nm(2) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

Limited occupational exposure to PR-Toxin may occur through inhalation and dermal contact with this compound at workplaces where specific cheeses contaminated with PR-Toxin is produced or served. Limited monitoring data indicate that the general population may be exposed to PR-Toxin via ingestion of cheese products contaminated with PR-Toxin. (SRC)