The effect of organophosphate pesticides on the blood glucose levels in the mouse

The aim of the present study was to study the effect of two selected agents of this group on blood glucose levels in an animal model. Forty-two adult male mice were divided into 7 groups of 6 each. Animals were exposed by their entire tail for 10 sec once a day for 7 successive days to either 0, 0.1, 1, or 10% azynphos methyl (AZP) malathion (MLT). On days 1,4 and 8, a small drop of blood was taken from tail of the animals that had been kept fasted overnight. Blood glucose levels were measure using a glucometer. The animals then were fed and after 1 h the blood glucose measurement was performed again. Results of this study indicated that the administration of organophosphate agents significantly prevented from the rise of blood glucose after feeding in comparison to the control animals. This reached the level of statistical significance on day 1 with MLT 1% (p < 0.001). It is concluded that exposure with organophosphate pesticides may suppress excessive blood glucose levels with no effect on the basal blood glucose in the fasting animals.     

Role of nitric oxide on the generation of atretic follicles in the rat ovaries

The aim of this study was to investigate the role of Nitric Oxide (NO) in the atresia of ovarian follicles in an animal model. Twenty adult, female rats (90 days old with body weights of210 +/- 10 g in the beginning of the experiments) were divided into 4 groups of 5 each. They were treated twice daily from the subcutaneous route for 21 successive days with either of the following chemicals: nitroglycerine, L-arginine, L-NAME, or saline. On day 22, all animals were sacrificed. Ovaries were dissected out free of connected tissue and were fixed in formaline 10%. Later, paraffine blocks were prepared and serial sections were made by means of H and E routine staining method. Intact and atretic follicles were counted separately. In addition, damages were analyzed qualitatively from the points of view of appearance and morphologic changes. In the evaluation of ovarian follicular structures, different types of healthy as well as atretic follicles were observed. In most of atretic follicles, the oocytes were abnormally elongated and increnation of their outlines were obvious. There were numerous macrophages around and inside of the atretic follicles. Our investigation regarding the distribution of atretic follicles in the ovaries of test groups revealed that atretic follicles in the L-NAME treated group were increased in comparison to the control group. Conversely, however, in the arginine-treated group, the atretic follicles were reduced compared to the control animals. Treatment with nitroglycerine of the rats decreased the number of atretic follicles significantly (p < 0.05) in comparison to the control group. In conclusion, enhanced NO, either from endogenous or exogenous origins, prevents atresia phenomenon, while inhibition of NO exerts an opposite effect.     

Effect of crop plant density on critical period of weed competition in potato

A field study was conducted in Hamedan western Iran in 2006 to establish the critical period of weed competition (CPWC) in potato (Solanum tuberosum L.) for commercial and seed production plant densities. A quantitative series of treatments concerned with both increasing duration of interference and length of weed-free period were imposed within each commercial and seed potato production plant density. The beginning and end of the CPWC based on a 10% loss of tuber yield was determined by fitting logistic and Gompertz equations to the relative tuber yield data representing increasing duration of weed interference and weed-free period, respectively. At a 10% tuber yield loss level, the duration of weed interference for 571 and 676 growing degree days (GDDs) from crop emergence, corresponding to 40% and 50% canopy closure, marked out the beginning of the CPWC for commercial and seed production plant densities, respectively. When maintained weed-free for 1163 and 1014 (GDD), corresponding to 100% and 80% canopy closure, weed emerging later caused tuber yield losses of less than 10% for commercial and seed production plant densities, respectively. Practical implications of this study are that post-emergence herbicides or other weed control methods should be used in western Iran to eliminate weeds from 19–24 days post-crop emergence up to 43–51 days. Such an approach would keep yield loss levels below 10%. Interactions between plant density and weed competition durations indicated that weed management in commercial plant density of potato could be less intensive than that of seed production plant density, reducing herbicide use and risk of herbicide carryover to sensitive rotation crops.