Biomonitoring with the comet assay of Greek greenhouse workers exposed to pesticides.

The pesticides in use in Greek greenhouses include a number of agents known to be mutagens and carcinogens. In the present study, we evaluated whether occupational exposure of agricultural workers to a complex mixture of pesticides resulted in a significant increase in DNA damage in human peripheral blood lymphocytes (PBLs). A total of 116 healthy individuals were divided into groups based on exposure to pesticides, smoking status, and gender. Alkaline comet assays performed on PBLs from these individuals indicated no statistically significant differences in basal DNA damage between the study groups. In addition, exposure of PBLs to a dose of hydrogen peroxide led to a similar degree of DNA damage and subsequent repair for all the study populations. The results of the study indicate that the agricultural workers who participated in this study had no detectable increase in DNA damage or alteration in the cellular response to DNA damage.

Male olive fruit fly attraction to synthetic sex pheromone components in laboratory and field tests.

Male olive fruit fly attraction to the four synthetic components of the female sex attractant pheromone was studied under laboratory and field conditions. In laboratory tests males responded to all four components tested separately. Component I, (1,7-dioxaspiro[5.5]undecane) was more attractive than any of the remaining three components alone, but a combination of all four was more attractive than component I alone. In field tests with polyethylene vials as pheromone dispensers, the complete mixture, although not statistically significant, was constantly more attractive to males than component I alone. A tendency of enhancement of attraction of component I by combining it with component II (α-pinene) or III (n-nonanal) was also observed. In field tests with rubber septa as pheromone dispensers only component I was attractive. Mixtures containing component I were also attractive but not more attractive than component I alone. Evaporation rate and ratio of components as they come out of the dispenser appear to be critical for male response.

A multicomponent female sex pheromone ofDacus oleae Gmelin: Isolation and bioassay.

The sex attractant pheromone produced by femaleDacus oleae Gmelin is a mixture of four compounds, two of which are found in the rectal gland and the other two elsewhere in the insect body. The ratio of these compounds in the pheromone blend was measured. Biological activity of all four compounds and their combinations was studied in lab and field cage tests. The most abundant compound in the mixture (55.7%) shows the highest biological activity. Recombination of all compounds significantly increases activity of the main compound.

1,5,7-Trioxaspiro[5.5]undecane, a pheromone analog with high biological activity for the olive fruit fly,Dacus oleae.

l,5,7-Trioxaspiro[5.5]undecane, an analog of the major sex pheromone (olean) of the olive fruit fly, was synthesized via two different routes and tested for biological activity under laboratory and field conditions. In laboratory tests, its activity was comparable to that of olean, especially when a stabilizer or a high concentration was used. In field tests, its activity reached the level of olean only when a stabilizer and an open-type dispenser, which allows high rates of evaporation, were used. The residual activity of the analog dispensers did not exceed two weeks both under laboratory and field conditions compared to over four months for olean.

Biological activity of chemicals identified from extracts and volatiles of maleRhagoletis cerasi.

Fractions obtained by chromatographic separation of extracts and volatiles from maleRhagoletis cerasi flies were tested for biological activity on females under laboratory conditions. During the bioassays, the number of incoming flies as well as the time spent by individual flies on the area of stimulus were taken under consideration. Two distinct types of female behavior were observed, i.e., attraction and arrestant behavior. GC-MS analysis of biologically active fractions resulted in tentative identification of 75 compounds. EAG screening for 27 of these compounds was performed, and subsequent laboratory bioassays resulted in the confirmation of arrestant activity for various mixtures of eight fatty acids (octadecanoic, nonadecanoic, eicosatetraenoic, eicosapenaenoic, eicosaenoic, heneicosanoic, docosahexenoic, and docosanoic). Following EAG tests and laboratory bioassays, a possible mode of chemical communication of this species with sex pheromones is proposed.

Sex-specific activity of (R)-(-)- and (S)- (+)-1,7-dioxaspiro[5.5]undecane, the major pheromone ofDacus oleae.

1,7-Dioxaspiro[5.5]undecane (olean), the major component of the female sex attractant pheromone blend of the olive fruit flyDacus oleae (Gmelin) was shown to be released as a racemate. The response of males and females to pure (R)-(-) and (S)-(+)-enantiomers was tested under laboratory and field conditions. Males in laboratory and field tests responded only to (R)-(-)-olean, which functions as a sex attractant. Females responded only to (S)-(+)-olean in laboratory tests but not in the field. There are indications that the latter enantiomer fuctions as a short-range arrestant throughout the day and as an aphrodisiac in the process of mating.