Browsing by Subject "Isothiocyanates"
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Item Effects of Oilseed Meals and Isothiocyanates (ITCS) on Phymatotrichopsis omnivora (Cotton Root Rot) and Soil Microbial Communities(2012-07-16) Hu, PingThe meals from many oilseed crops contain biocidal chemicals that are known to inhibit the growth and activity of several soil pathogens, though little is known concerning impacts on whole soil microbial communities. We investigated the effect of oilseed meals (SMs) from both brassicaceous plants, including mustard and camelina, as well as non-brassicaceous plants, including jatropha and flax, on P. omnivora (the casual agent of cotton root rot) in Branyon clay soil (at 1 and 5% application rates). We also investigated the effect of SMs from camelina, jatropha, flax, and wheat straw on microbial communities in Weswood loam soil. We also used four types of isothiocyanates (ITCs) including allyl, butyl, phenyl, and benzyl ITC to test their effects on P. omnivora growth on potato dextrose agar (PDA), as well as on soil microbial communities in a microcosm study. Community qPCR assays were used to evaluate relative abundances of soil microbial populations. Soil microbial community composition was determined through tag-pyrosequencing using 454 GS FLX titanium technology, targeting ITS and 16S rRNA gene regions for fungal and bacterial communities, respectively. The results showed that all tested brassicaceous and jatropha SMs were able to inhibit P. omnivora sclerotial germination and hyphal growth, with mustard SM being the most effective. Flax didn't show any inhibitory effects on sclerotial germination. All tested ITCs inhibited P. omnivora OKAlf8 hyphal growth, and the level of inhibition varied with concentration and ITC type. Total soil fungal populations were reduced by ITC addition, and microbial community compositions were changed following SM and ITC application. These changes varied according to the type of SM or ITC added. Our results indicated that SMs of several brassicaceous species as well as jatropha may have potential for reducing cotton root rot as well as some other pathogens. Different SMs releasing varied ITCs may result in differential impacts on soil microorganisms including some pathogens.Item Induction of apoptosis and cell cycle arrest in renal carcinoma cells by phenethyl isothiocyanate and the mechanisms involved(2011-05) Khan, Maruf; DeGraffenried, Linda; Ciolino, Henry P.; Sanders, Bob G.; Nunez, Nomeli P.; Fischer, Susan M.Renal Cell Carcinoma (RCC) has low 5 year survival rate and is resistant to radiation and chemotherapy. Phenethyl Isothiocyanate (PEITC) is a naturally occurring phytochemical that has a variety of anti-cancer properties. Here we explore two anti-cancer properties of PEITC: induction of apoptosis and induction of cell cycle arrest in RCC cells and the underlying mechanisms. We used two human RCC cell lines Caki-1 and Caki-2. Survival and cell proliferation was assayed using Calcein AM. Annexin V staining was used to measure apoptosis. Caspase-3/7 induction was measured using a fluorescent substrate. Cell cycle was studied using Propidium Iodide staining. DNA damage was determined using phospho [gamma]-H2AX antibody. Protein expression and phosphorylation was determined using immunoblotting. PEITC significantly reduced survival of Caki-1 and Caki-2 cells and inhibited their proliferation as determined by Calcein AM. 15 and 20 [mu]M PEITC induced apoptosis in both cell lines and induced caspase-3/7 activity. Western blot analysis revealed caspase-8, caspase-9 and Bid cleavage as well as upregulation of the death receptors Fas and DR5. Lower doses (up to 10 [mu]M) arrested Caki-1 cells in G2/M phase, and this was associated with increased p38 and MK2 (Thr334) phosphorylation. The p38 inhibitor SB203850 inhibited this G2 arrest induced by PEITC. 15 and 20 [mu]M PEITC treatment resulted in increased [gamma]-H2AX phosphorylation suggesting DNA damage, but this was completely blocked by caspase inhibitor. In summary, our study shows that PEITC induces apoptosis in Caki-1 and Caki-2 cells by upregulating Fas and DR5 and activating the downstream apoptosis cascade. PEITC does not cause direct DNA damage to the cells; the observed DNA damage is a result of the apoptotic process and is blocked by caspase inhibitor. PEITC induces G2/M arrest in Caki-1 cells and the mechanism involves p38 phosphorylation which activates MK2. Inducing cell cycle arrest and apoptosis may play an important role in the anti-cancer properties of PEITC. Fully understanding the mechanism by which PEITC induces apoptosis and cell cycle arrest in RCC cells may lead to development of novel chemotherapeutic drugs against RCC.