Effect of nonpersistent pesticides on estrogen receptor, androgen receptor, and aryl hydrocarbon receptor.

Nonpersistent pesticides are considered less harmful for the environment, but their impact as endocrine disruptors has not been fully explored. The pesticide Switch was applied to grape vines, and the maximum residue concentration of its active ingredients was quantified. The transactivation potential of the pesticides Acorit, Frupica, Steward, Reldan, Switch, Cantus, Teldor, and Scala and their active compounds (hexythiazox, mepanipyrim, indoxacarb, chlorpyrifos-methyl, cyprodinil, fludioxonil, boscalid, fenhexamid, and pyrimethanil) were tested on human estrogen receptor α (ERα), androgen receptor (AR) and arylhydrocarbon receptor (AhR) in vitro. Relative binding affinities of the pure pesticide constituents for AR and their effect on human breast cancer and prostate cancer cell lines were evaluated. Residue concentrations of Switch's ingredients were below maximum residue limits. Fludioxonil and fenhexamid were ERα agonists (EC50 -values of 3.7 and 9.0 µM, respectively) and had time-dependent effects on endogenous ERα-target gene expression (cyclin D1, progesterone receptor, and nuclear respiratory factor 1) in MCF-7 human breast cancer cells. Fludioxonil, mepanipyrim, cyprodinil, pyrimethanil, and chlorpyrifos-methyl were AhR-agonists (EC50 s of 0.42, 0.77, 1.4, 4.6, and 5.1 µM, respectively). Weak AR binding was shown for chlorpyrifos-methyl, cyprodinil, fenhexamid, and fludioxonil. Assuming a total uptake which does not take metabolism and clearance rates into account, our in vitro evidence suggests that pesticides could activate pathways affecting hormonal balance, even within permitted limits, thus potentially acting as endocrine disruptors.

Purification of infective baculoviruses by monoliths.

A chromatographic process based on monoliths for purification of infective baculovirus without prior concentration step has been established. Baculovirus produced in Spodoptera frugiperda cells (Sf-9) were harvested by centrifugation, filtered through 0.8 µm filters and directly loaded onto radial 1 mL anion exchange monoliths with a channel size of 1.5-2.0 µm operated at a volumetric flow rate of one bed volume per minute. Optional an epoxy monolith was used as pre-column to reduce interfering compounds and substances influencing the capacity of anion exchange monoliths for baculovirus infectious virus could be eluted with a step gradient at salt concentrations of 440 mM NaCl. Recovery of infectious virus was highly influenced by composition and age of supernatant and ranged from 20 to >99% active baculovirus. Total protein content could be reduced to 1-8% and DNA content to 38-48% in main virus fraction. Infective virus could be 52-fold concentrated within 20.5h and simultaneously an 82-fold volume reduction was possible when loading 1150 mL (2.1×10(8) pfu/mL) onto 1 mL scale support.

Red clover and soy isoflavones--an in vitro safety assessment.

Isoflavones from red clover and soy plant extracts are used in highly concentrated food supplements as an alternative to hormone replacement therapy. Due to their estrogenic activity, isoflavones are a focus of safety concerns about their potential to promote the growth of hormone-dependent cancer cells. In this study, isoflavones and plant extracts were tested for their effect on cell proliferation, apoptosis induction and cell cycle arrest. Isoflavones and plant extracts were applied in proliferation assays on 11 human cancer cell lines (representing cancers of the colon, prostate, breast, cervix, liver, pancreas, stomach and ovaries) and a fibroblast line to detect cytotoxic activity. Fluorescence-activated cell sorting was used to detect the induction of apoptosis or cell cycle arrest. Isoflavones and plant extracts significantly reduced the proliferation activity of the treated cancer cell lines. Growth promotion was not observed, but apoptosis or necrosis induction was, as was cell cycle arrest, with genistein as the most potent isoflavone. Isoflavones and plant extracts from soy and red clover, respectively, do not promote the growth of human cancer cells but induce decreased cell proliferation, increased apoptosis and cell cycle arrest. These results indicate that isoflavones can be considered safe compounds.