Teratogenic and dominant lethal studies of patulin in mice

Bio-Layer Interferometry-Based SELEX and Label-Free Detection of Patulin Using Generated Aptamer

This study reports a novel bio-layer interferometry (BLI)-based SELEX for generation of high affinity aptamers against patulin. Unlike conventional SELEX, the present method enabled real-time monitoring of increasing affinity of the oligonucleotides to the toxin. After seven rounds of selection cycles, the enriched pool of aptamers was characterized by cloning and sequencing and clustered into two families based on similarity. Two sequences, PAT C3 and PAT C4, each belonging to different clades, were further evaluated for their binding affinity. SPR studies determined the dissociation constants (K_D) of 8.2 × 10^-8 and 1.9 × 10^-7 M for aptamer PAT C3 and PAT C4, respectively. The highest affinity PAT C3 aptamer was used to develop a patulin BLI aptasensor, which indicated a linear detection range from 0.045 to 100 ng/mL [limit of detection (LOD) = 0.173 ng/mL; limit of quantification (LOQ) = 0.526 ng/mL]. The aptasensor displayed no cross-reactivity with its structural analogue isopatulin or any of the other mycotoxin groups tested. Spiking studies in simulated apple juice samples showed recoveries in the range of 82.11 to 100.23%, indicating good sensor performance. The study is the first report of BLI-based SELEX for a non-protein toxin, which resulted in the generation of high affinity aptamers and development of an aptasensor which can have wide application in the food industry for high throughput screening of samples for patulin contamination within a short span of time.

In vitro antitumor activity of patulin on cervical and colorectal cancer cell lines

Background and Purpose:

Patulin is a mycotoxin produced by some molds, especially Aspergillus and Penicilium, and is responsible for mycotoxicosis in animals and humans.

There is still not very detailed data about the anti-cancer potency of patulin, but some reports demonstrated that it induces cellular apoptosis and toxicity.

Materials and Methods:

To determine the efficacy of patulin as a therapeutic strategy for cervical and colorectal cancers, we investigated its effects on HeLa,SW-48, and MRC-5 cell lines. Cell lines were exposed to various concentrations of patulin (i.e., 0.5, 1, 2, and 4 µM), then using methyl thiazolyl tetrazolium (MTT) and bromo-2′-deoxyuridine (BrdU) assays, the rates of apoptosis and cell viability were determined.

Results:

The obtained results showed a significant reduction in cell viability and apoptosis induction in a dose-dependent manner. Among all the cell lines, the highest growth inhibition rate was obtained at the 4 μM concentration of patulin.

Conclusion:

Our results suggested that patulin could significantly decrease tumor growth in human cervical and colorectal cancer models.

In vitro antitumor activity of patulin on cervical and colorectal cancer cell lines

BACKGROUND AND PURPOSE

Patulin is a mycotoxin produced by some molds, especially Aspergillus and Penicilium, and is responsible for mycotoxicosis in animals and humans.There is still not very detailed data about the anti-cancer potency of patulin, but some reports demonstrated that it induces cellular apoptosis and toxicity.

MATERIALS AND METHODS

To determine the efficacy of patulin as a therapeutic strategy for cervical and colorectal cancers, we investigated its effects on HeLa,SW-48, and MRC-5 cell lines. Cell lines were exposed to various concentrations of patulin (i.e., 0.5, 1, 2, and 4 µM), then using methyl thiazolyl tetrazolium (MTT) and bromo-2'-deoxyuridine (BrdU) assays, the rates of apoptosis and cell viability were determined.

RESULTS

The obtained results showed a significant reduction in cell viability and apoptosis induction in a dose-dependent manner. Among all the cell lines, the highest growth inhibition rate was obtained at the 4 μM concentration of patulin.

CONCLUSION

Our results suggested that patulin could significantly decrease tumor growth in human cervical and colorectal cancer models.

An Analysis of the Hydra Assay's Applicability and Reliability as a Developmental Toxicity Prescreen

A large and diverse group of chemicals was evaluated in the Hydra assay, and the outcomes were compared with those of standard developmental toxicity evaluations using data from pregnant mammals. Hydra correctly identified each of the substances previously found by in vivo tests to be uniquely hazardous to in utero development. Its overall accuracy was over 90%, and all of its errors were false positives. The fact that these positives were indeed false could have been established subsequently by routine testing in mammals. In no instance did the assay indicate that a chemical was not uniquely hazardous to the conceptus when higher level tests indicated that it was, i.e., 0 false negatives. The possible areas for continued refinement of the assay and expansion of its scope of use as well as perceived problems and limitations are discussed in detail.

Mycelium of fungi isolated from mouldy foods inhibits Staphylococcus aureus including MRSA - A rationale for the re-introduction of mycotherapy?

Fungal mycelium capable of producing antibacterial agents was isolated from samples of apple, beetroot, lemon and orange; the mycelium of all isolates produced penicillin, while the apple and beetroot samples also produced the antibacterial mycotoxin patulin. The known penicillin-producing fungi were shown to produce penicillin, but not patulin. The mycelial discs of all of fruit and vegetable isolates, as well as the two known penicillin producing fungi, inhibited Staphylococcus aureus, and mycelium of all isolates inhibited MRSA, in contrast, only one of the two known penicillin-producers did so. The results are discussed in relation to the possibility of using the mycelium of Penicillium species in mycotherapy.

Biosynthesis and toxicological effects of patulin

Patulin is a toxic chemical contaminant produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys. It is the most common mycotoxin found in apples and apple-derived products such as juice, cider, compotes and other food intended for young children. Exposure to this mycotoxin is associated with immunological, neurological and gastrointestinal outcomes. Assessment of the health risks due to patulin consumption by humans has led many countries to regulate the quantity in food. A full understanding of the molecular genetics of patulin biosynthesis is incomplete, unlike other regulated mycotoxins (aflatoxins, trichothecenes and fumonisins), although the chemical structures of patulin precursors are now known. The biosynthetic pathway consists of approximately 10 steps, as suggested by biochemical studies. Recently, a cluster of 15 genes involved in patulin biosynthesis was reported, containing characterized enzymes, a regulation factor and transporter genes. This review includes information on the current understanding of the mechanisms of patulin toxinogenesis and summarizes its toxicological effects.

Current status of bioassays in genetic toxicology--the dominant lethal assay. A report of the U.S. Environmental Protection Agency Gene-Tox Program

The term dominant lethal may be defined as death of the heterozygote arising through multiple chromosomal breaks. The assay is generally conducted by treating male animals, usually mice or rats, acutely (1 dose), subacutely (5 doses), or over the entire period of spermatogenesis. Animals treated acutely or subacutely are mated at weekly intervals to females for a sufficient number of weeks to cover the period of spermatogenesis. Those treated for the entire spermatogenic cycle are mated for 1 or 2 successive weeks at the termination of treatment. Females usually are killed at 14 days of pregnancy and examined for the number of total implantations in the uterus, the number of implantations classified as early deaths, and, in some cases, the number of corpora lutea. The category of early death is the most significant index of dominant lethality. A total of 249 papers were reviewed and 140 chemicals were evaluated. Of the 140 chemicals, 65 were positive by the criteria used by the Work Group in evaluating each publication. The category of "positive" includes those responses of a borderline nature. 99 chemicals were declared negative. There is considerable overlap of chemicals in both categories, which accounts for the incongruity in the total number of chemicals tested and the number considered positive and negative. A total of 44 animal carcinogens have been tested in the dominant lethal assay, 26 of which were positive and 18 negative for a correlation of 59%. The role of the assay should be that of confirming positive results from lower tier chromosomal aberration-detecting systems (confirming in the sense of indicating the ability of the chemical to penetrate gonadal tissue and to produce cytogenetic damage). The dominant lethal assay should not be used as a risk assessment method.

The effects of patulin and patulin-cysteine mixtures on DNA synthesis and the frequency of sister-chromatid exchanges in human lymphocytes

The effects of patulin and patulin-cysteine mixtures on DNA synthesis in human blood lymphocytes were measured by assaying incorporation of [3H]thymidine into cellular DNA. Patulin inhibited and patulin-cysteine mixtures stimulated the incorporation of [3H]thymidine into DNA. The inhibitory action of patulin diminished with time in culture. Patulin was found to be unstable in the culture medium. The sister-chromatid exchange (SCE) frequency was significantly elevated by intermediate concentrations (0 . 1-0 . 2 micrograms/ml culture) of the toxin. The cells are protected from the effect at low concentrations of the toxin. There may be excessive damage at higher concentrations but only the unaffected cells go into mitosis. Therefore an increased frequency of SCEs is detected only at intermediate concentrations, or, at higher concentrations, with early harvesting. Cysteine seems to potentiate the effect of patulin on SCE frequency.

Embryocidal, teratogenic and fetotoxic effects of citrinin in rats

Citrinin, a fungal metabolite produced by several species of Penicillium and Aspergillus, has been found to contaminate foods used by animals and man. Citrinin is nephrotoxic and has been implicated in disease outbreaks in animals and humans. In this study the teratogenicity, embryotoxicity, and fetotoxicity of citrinin was determined in Sprague-Dawley rats after subcutaneous administration of a single dose of 35 mg/kg on gestation day 3, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. Dams so treated lost weight for 2 days following administration. Subsequently, weight gain for treated animals was similar to that for controls. Relatively high maternal mortalities also were associated with this pretreatment regimen. Treatment with 35 mg/kg on certain days of gestation resulted in deaths of one half or more of the pregnant dams. No significant effects of citrinin were observed on the number of implants. Resorption of implants, however, was higher in treated animals than controls when dams were treated on days 6, 7, 8, 10, 11 or 12 of gestation. Fetuses from dams given citrinin were significantly smaller than those from controls by about 22% on average. No major gross or skeletal malformations were found in fetuses born to mothers which received citrinin. Major internal soft tissue malformations seen were enlarged kidneys, internal hydrocephalus and cleft palate.

Teratogenicity of secalonic acid D in mice

Teratogenicity and fetotoxicity of secalonic acid D, a toxic fungal metabolite produced by Penicillium oxalicum, were investigated with pregnant CD1 mice. The compound was administered ip on d 7-15 of pregnancy. A dose-dependent reduction in weight gain of mothers receiving all doses of secalonic acid D and an increase in resorptions of implanted embryos of dams treated with more than 5 mg/kg secalonic acid D occurred. The latter effect was nearly 100% at 15 or 9 mg/kg given in NaHCO3 with or without dimethyl sulfoxide (DMSO), respectively. A corresponding decrease in the percent of live fetuses and a decrease in the average fetal body weight on d 19 of pregnancy also occurred. Multiple gross, skeletal, and visceral anomalies were noted in fetuses born to mothers receiving 10 mg/kg or more in NaHCO3 containing DMSO. In NaHCO3 alone, the minimum teratogenic dose was 6 mg/kg. Major malformations included cleft palate, cleft lip, open eyelids, missing phalangeal ossification centers, and shortened mandibles. The results indicated that secalonic acid D is embryocidal and teratogenic as well as fetotoxic when given to female CD1 mice during pregnancy.

Chromosomal analysis in bone-marrow cells of Chinese hamsters after treatment with mycotoxins

Mycotoxins are ubiquitously occurring metabolites of moulds that grow on foodstuffs. They are able to cause toxic diseases in man and animals. Aflatoxin B1 (AFB1), aflatoxin G1 (AFG1) and platulin (PA) induce chromosomal damage in Chinese hamster bone-marrow cells. With respect to the number of induced aberrant mitoses the 3 mycotoxins can be ranked in the order PA greater than AFB1 greater than AFG1.