Dose-Response on the Chemopreventive Effects of Sarcophine-Diol on UVB-Induced Skin Tumor Development in SKH-1 Hairless Mice

Sarcophine-diol (SD) is a lactone ring-opened analogue of sarcophine. It has shown chemopreventive effects on chemically-induced skin tumor development in female CD-1 mice, as well as in a UVB-induced skin tumor development model in hairless SKH-1 mice at a dose of 30 μg SD applied topically and 180 mJ/cm² UVB. The objective of this study was to determine the dose-response on the chemopreventive effects of SD on SKH-1 hairless mice when exposed to a UVB radiation dose of 30 mJ/cm². This UVB dose better represents chronic human skin exposure to sunlight leading to skin cancer than previous studies applying much higher UVB doses. Carcinogenesis was initiated and promoted by UVB radiation. Female hairless SKH-1 mice were divided into five groups. The control group was topically treated with 200 μL of acetone (vehicle), and the SD treatment groups were topically treated with SD (30 μg, 45 μg, and 60 μg dissolved in 200 μL of acetone) 1 h before UVB radiation (30 mJ/cm²). The last group of animals received 60 μg SD/200 μL acetone without UVB exposure. These treatments were continued for 27 weeks. Tumor multiplicity and tumor volumes were recorded on a weekly basis for 27 weeks. Weight gain and any signs of toxicity were also closely monitored. Histological characteristics and the proliferating cell nuclear antigen (PCNA) were evaluated in the mice skin collected at the end of the experiment. The dose-response study proved a modest increase in chemopreventive effects with the increase in SD dose. SD reduced the number of cells positively stained with PCNA proliferation marker in mice skin. The study also showed that SD application without UVB exposure has no effect on the structure of skin. The results from this study suggest that broader range doses of SD are necessary to improve the chemopreventive effects.     

Tomato waste compost as an alternative substrate to peat moss for the production of vegetable seedlings

Different proportions of tomato waste compost (TWC) were combined with peat moss and vermiculite as growth substrates used to evaluate the quality of seedlings of economic vegetables, including tomato, hot pepper, cucumber and summer squash. The seeding substrates used were: (T0), vermiculite: peat moss: TWC (4: 1: 0, by weight), 0% TWC; (T1), vermiculite: peat: TWC (4: 0.75: 0.25), 5% TWC; (T2), vermiculite: peat: TWC (4: 0.5: 0.5), 10% TWC; (T3), vermiculite: peat: TWC (4: 0.25: 0.75), 15% TWC; and (T4), vermiculite: peat: TWC (4: 0: 1), 20% TWC. The best seedling response was recorded in substrate mixtures supplemented with 5% and 10% TWC, which hastened seed germination and improved seedling morphology. Since vegetable seedlings produced with TWC-amended substrate were of higher quality, compared to those produced exclusively on peat substrate, we suggest that TWC may be used to replace partially peat-based substrate used for vegetable transplants production in nurseries.     

Genetic diversity of Nile tilapia populations revealed by randomly amplified polymorphic DNA (RAPD)

Genetic diversity of the Nile tilapia Oreochromis niloticus collected from the river Nile (Cairo, Assuit and Qena) and two Delta lakes (Burullus and Manzalla) in Egypt was examined by the analysis of randomly amplified polymorphic DNA (RAPD). Of 25 primers examined,21 primers produced 230 RAPD bands. The percentage of polymorphic bands in Manzalla (29.4%) and Burullus (24%) populations was low compared with Assuit (30.54%), Cairo (33.5%) and Qena (44.84%) populations. The highest percentage of polymorphic bands was observed in the Qena population,suggesting a greater potential for use in breeding programs. The molecular phylogenetic tree constructed by unweighted pair‐group method of analysis shows Manzalla and Burullus populations strongly linked and separate from the Assuit and Cairo populations, with Qena population as outgroup. The data serve as a baseline analysis of the current genetic diversity found among O. niloticus populations in Egypt.