Impact of EMS outreach: successful developments in Latin America

This collection of articles was inspired by the long-standing relationship between the Environmental Mutagen Society and Latin American scientists, and by the program for the 39th Environmental Mutagen Society meeting in Puerto Rico in 2008, which included a symposium featuring "South of the border" scientists. This collection, compiled by Graciela Spivak and Ofelia Olivero, both originally from Argentina, highlights scientists who work in or were trained in Latin American countries and in Puerto Rico in a variety of scientific specialties related to DNA repair and cancer susceptibility, genomic organization and stability, genetic diversity, and environmental contaminants.

Determination of genotoxicity of classical swine fever vaccine in vitro by cytogenetic and comet tests

Chromosome damage in lymphocyte cultures induced by live virus vaccine against classical swine fever (CSF) has been observed in previous studies. In vivo cytogenetic tests were made with several doses of vaccines used in Argentina to control the disease. These studies have shown that genotoxic effects increased with dose. In the present study, two different in vitro assays were performed by recording the frequency of cells with chromosome alterations and by assessing the ability of the vaccine to damage DNA, using the single cell gel microelectrophoretic assay (comet test). Frequencies of cells with chromosomal alterations increased significantly when compared with controls and were dose (microl/ml) dependent: 0 = 1.23, 5 = 2.29, 10 = 5.42 and 20 = 11.71%. In the comet assay the variables measured, tail length (TL) and tail moment (TM), also increased. For control cultures TL was 2.32 microm, whereas with concentrations of 20 and 100 microl/ml TL were 12.47 and 42.3 microm, respectively. TM of control cultures was 0.18, whereas with vaccine concentrations of 20 and 100 microl/ml TM were 5.52 and 24.52, respectively. Comet frequency distributions differed significantly among treatments. These results agree with previous in vivo observations. Regarding CSF pathogeny, our results support a direct effect of CSF vaccinal virus on lymphocyte DNA. Genotoxicity of CSF vaccine was corroborated in vitro at the cytogenetic and molecular levels.

Anti-genotoxic effect of Aloysia triphylla infusion against acrylamide-induced DNA damage as shown by the comet assay technique

Aloysia triphylla a perennial, bushy plant originally from South America has long been used in traditional medicine. Its aqueous extract contains considerable amounts of polyphenolic compounds, namely flavonoids and phenolic acids. In view of the interest in natural phenolic compounds as antioxidant in preventive medicine, this study was undertaken to investigate the chemoprotective effects of cedron leaves infusion against the genetic damage induced by acrylamide (AA) by using the alkaline version of the comet assay technique. Mice were separated in nine groups (eight animals each): (I) untreated, (II) negative control, (III) treated with infusion of cedron leaves 5%, 20 days twice a day, (IV) treated with AA (5 mg/kg b.w.), (V) treated with AA (20 mg/kg b.w.), (VI) treated with AA (30 mg/kg b.w.), (VII) treated with AA (50 mg/kg b.w.), (VIII) pretreated with infusion and treated with AA (50 mg/kg b.w.) and (IX) positive control (cyclophosphamide, 20 mg/kg b.w.). Three hundred blast cells were digitally evaluated per animal from three different slides (100 each). Media of tail moment (TM) values were analyzed by ANOVA test. No statistical differences (p>0.05) were found between untreated animals, negative control and infusion-treated mice. A single dose of AA-induced genetic damage as revealed by a statistically significant increase in TM values (p<0.01). Pretreatment with infusion prior to AA injection significantly reduces the capacity of AA to induce genetic damage. In these conditions, tail moments values did not differ from data obtained in negative control (p>0.05) and exhibit statistical differences from animals treated only with AA (p<0.01). Cell viability was at least 90% in all cases as measured by the trypan blue exclusion method. The ferric reducing ability of plasma (FRAP) method reveals that the plasma of infusion-treated mice has a significantly higher antioxidant capacity than plasma from controls (p<0.01). The results suggest that the infusion could exerts an in vivo chemo protective action, probably due to its scavenging potency towards free radicals.

Pentachlorophenol inhibits micronuclei induction by 2-acetylaminofluorene but not by thioacetamide

Our study examined the capacity of pentachlorophenol (PCP) to inhibit the ability of 2-acetylaminofluorene (2-AAF) and thioacetamide (TAA) to induce micronuclei in mouse bone marrow cells in vivo. 2-AAF (5.6mg/kg) and TAA (60mg/kg) were administered intra-peritoneally (i.p.) to Mus musculus males (BALB/c), and the frequencies of polychromatic erythrocytes with micronuclei (PCE-MN) 24h after injection were analyzed. Treatment with 2-AAF or TAA resulted in high PCE-MN frequencies in comparison with untreated and negative controls (19.9 and 21.6‰, respectively, versus ≈3‰). Pretreatment with a single PCP dose (44mg/kg) 24h prior to the 2-AAF administration virtually eliminated micronuclei formation by 2-AAF, although it had no inhibitory effect on TAA-induced micronuclei. Animals receiving cyclophosphamide (CP) served as positive control. Since PCP is known to inhibit arylsulfotransferase (AST) activity, which is involved in 2-AAF activation, this mechanism most likely produced the results with PCP and 2-AAF. Our results also are consistent with a different pathway involved in TAA induction of micronuclei, one that is not inhibited by PCP.

Protective activity of cedron (Aloysia triphylla) infusion over genetic damage induced by cisplatin evaluated by the comet assay technique

Using the comet assay technique, this paper examines the protection from the cisplatin-induced genetic damage in mouse bone marrow cells provided by cedron-leaf infusion. Animals were separated into six groups: (I) untreated, (II) negative control, (III) treated with cedron-leaf infusion (5%), (IV) treated with cisplatin (6 mg/kg b.w.), (V) pretreated with infusion and treated with cisplatin and (VI) positive control (cyclophosphamide, 20 mg/kg b.w.). Based on the tail moment values found, four types of comets were distinguished. No statistical differences (P<0.01) were found between untreated animals, negative control and infusion treated mice. As expected, treatment of mice with a single dose of cis-DDP-induced genetic damage and the pretreatment with infusion prior to cis-DDP injection inhibited the capacity of cisplatin to induce genetic damage. Cell viability was up to 90% in all cases. The results suggest that infusion could exert its in vivo antigenotoxic action by enhancing the antioxidant status of bone marrow cells. The found could be attributed to its scavenging potency towards free radicals.

Production and purification of statins from Pleurotus ostreatus (Basidiomycetes) strains

Pleurotus ostreatus strains were cultured in liquid medium and on wheat straw. The yields of lovastatin were compared.