In this work the antifeedant effects of the halogenated monoterpenes 1-13 were tested against several divergent insect species. These compounds have been isolated from Plocamium cartilagineum (6 was isolated as an acetyl derivative), except for 4, which was isolated from Pantoneura plocamioides. We have also included the semisynthetic derivatives 1a, 2a, and 7. Compounds 1, 1a, 2, 4, 5, 7, 8-10, and 13 were antifeedants against Leptinotarsa decemlineata with varying potencies. The aphids Myzus persicae and Ropalosiphum padi were strongly deterred in the presence of compounds 2, 12, and 13. This effect was correlated with the electronic recording of their probing behavior. Compounds 2 and 12 were toxic to L. decemlineata and had selective cytotoxicity to insect-derived Sf9 cells. None of the tested compounds showed phytotoxic effects. The antifeedant and cytotoxic effects of these compounds were compared with those of the polyhalogenated insecticide gamma-hexachlorocyclohexane (lindane).
BackgroundCancer stem cells (CSCs) are a subset of tumor cells with capacity to self-renew and generate the diverse cells that make up the tumor. The aim of this study is to evaluate the prognostic value of CSCs in a highly homogeneous population of stage II colon cancer.MethodsOne hundred stage II colon cancer patients treated by the same surgical team between 1977 and 2005 were retrospectively analyzed. None of the patients received adjuvant chemotherapy. Inmunohistochemistry expression of CD133, NANOG and CK20 was scored, using four levels: <10%, 11–25%, 26–50% and >50% positivity. Kaplan-Meier analysis and log rank test were used to compare survival.ResultsThe average patient age was 68 years (patients were between 45–92 years of age) and median follow up was 5.8 years. There was recurrent disease in 17 (17%); CD133 expression (defined by >10% positivity) was shown in 60% of the tumors, in 95% for NANOG and 78% for CK20. No correlation was found among expression levels of CD133, NANOG or CK20 and relapse-free survival (RFS) or overall survival (OS). However, a statistical significant correlation was found between established pathological prognostic factors and RFS and OS.ConclusionsStem Cell quantification defined by CD133 and NANOG expression has no correlation with RFS or OS in this cohort of Stage II colon cancer.
Exposure of bean plants grown in the greenhouse, where UV-B is low, to ambient levels of UV-B light stimulated nodulation more than 2.5-fold. Reduction of UV-B radiation to 3% of ambient levels for outdoor-grown plants through use of Mylar filters consistently reduced nodulation by 45%. The increase in nodulation caused by UV-B was mainly due to an increase in number and size of nodules. The amounts of UV-B-absorbing compounds in roots of UV-B-exposed plants increased almost 5-fold. However, the composition of UV-B-absorbing compounds remained very similar. Exposing leaves to UV-B also significantly increased release of these compounds from roots to the medium. These results suggest that UV-B radiation enhances nodulation, and that a signal may be transported from shoot to roots to play a role in nodulation.
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