Influence of physical factors on the growth of insect cells in vitro

Summary The tolerances of a cell line (IMC-HZ-1) from a moth,Heliothis zea, for the monovalent cations Na⁺ and K⁺ were defined. Cells shifted to media containing more than 70mm of K⁺ showed decreased growth rates. No evidence was obtained for Na⁺ toxicity. The osmotic pressure tolerances were influenced by the K⁺ concentration of the medium. The richer the medium was in K⁺, the narrower was the spectrum of osmotic pressure tolerance. Once the limit of K⁺ tolerance was exceeded, the rate of decline of growth was linear with respect to further increases in K⁺. This rate of decline was independent of osmotic pressure. The initial responses of cells during one subculture (2 to 4 population doublings) in media differing from the standard medium (used to maintain the cell line) were not reliable indicators of the growth potential of the cells. Continued subculture in such media resulted in an upward trend in population growth rates in most cases. This investigation was supported by U. S. Public Health Service Research Grant no. AI 09914 from the National Institute of Allergy and Infectious Diseases. This is Paper no. 8637, Scientific Journal Series, Minnesota Agricultural Experiment Station. The material is part of the dissertation of T. J. K. presented for the Ph.D. degree at the University of Minnesota.     

Unusual reactivity in a commercial chromium supplement compared to baseline DNA cleavage with synthetic chromium complexes

Commercially available chromium supplements were tested for their DNA cleavage ability compared with synthetic chromium(III) complexes, including chromium(III) tris-picolinate [Cr(pic)3], basic chromium acetate [Cr3O(OAc)6]+, model complexes, and recently patented Cr-complexes for use in supplements or therapy. Four different supplements (P1-P4) were tested for their DNA cleaving activity in the presence and the absence of H2O2, dithiothreitol (DTT) or ascorbate. One supplement, P1, showed nicking of DNA in the absence of oxidant or reductant at 120 microM metal concentration. Different lot numbers of P1 were also tested for DNA cleavage activity with similar results. Commercial supplements containing Cr(pic)3 nicked DNA at 120 microM metal concentrations in the presence of 5 mM ascorbate or with excess hydrogen peroxide, analogous to reactions with synthetic Cr(pic)3 reported elsewhere. Another chromium (non-Cr(pic)3) supplement, P2, behaves in a comparable manner to simple Cr(III) salts in the DNA nicking assay. Chromium(III) malonate [Cr(mal)2] and chromium(III) acetate [Cr(OAc)] can nick DNA in the presence of ascorbate or hydrogen peroxide, respectively, only at higher metal concentrations. The Cr(III) complexes of histidine, succinate or N-acetyl-L-glutamate do not nick DNA to a significant degree.     

Differential apoptotic and redox regulatory activities of curcumin and its derivatives

We have synthesized different bioconjugates of curcumin, which were tested for their pro- and antioxidant properties. In the present study five representative derivatives of curcumin, i.e., 4,4'-di-(O-acetyl) curcumin, 4,4'-di-(O-glycinoyl) curcumin, 4,4'-di-(O-glycinoyl-di-N-piperoyl) curcumin, 4,4'-di-(O-piperoyl) curcumin, and 4,4'-(O,O-cystinoyl)-3,3'-dimethoxydiphenyl-1,6-heptadiene-3,5-dione, were used for testing their apoptotic potential on tumor cells. Dipiperoyl and diglycinoyl derivatives showed higher apoptotic activity at lower concentrations, whereas diacetyl curcumin had slightly lower apoptotic activity on tumor cells. On the other hand, diglycinoyl-dipiperoyl and cystinoyl heptadiene derivatives had lost their apoptotic potential significantly. The apoptotic activity of these derivatives correlated very well with the generation of ROS by the tumor cells, whereas GSH levels remained unaltered. Our studies also indicate downregulation of Bcl-2 and participation of caspase-3 in the apoptotic death of tumor cells.     

Supplementation with flax oil and vitamin C improves the outcome of Attention Deficit Hyperactivity Disorder (ADHD)

Considerable clinical and experimental evidence now supports the idea that deficiencies or imbalances in certain highly unsaturated fatty acids may contribute to a range of common developmental disorders including Attention Deficit Hyperactivity Disorder (ADHD). Few intervention studies with LCPUFA supplementation have reported inconsistent and marginal results. This pilot study evaluates the effect of alpha linolenic acid (ALA)-rich nutritional supplementation in the form of flax oil and antioxidant emulsion on blood fatty acids composition and behavior in children with ADHD. Post-supplementation levels of RBC membrane fatty acids were significantly higher than pretreatment levels as well as the levels in control. There was significant improvement in the symptoms of ADHD reflected by reduction in total hyperactivity scores of ADHD children derived from ADHD rating scale.     

Comparative evaluation of possible ocular photochemical toxicity of fluoroquinolones meant for ocular use in experimental models

Fluoroquinolones (FQs) are extensively used in bacterial keratitis and other intraocular infections. Since eye is constantly exposed to light, incidence of ocular phototoxicity due to commonly used FQs is of great interest for their safe use. Phototoxicity of commonly used FQs (ciprofloxacin, lomefloxacin, pefloxacin, ofloxacin, sparfloxacin and gatifloxacin), has been evaluated by using HET-CAM-UV model (Photo Hen Egg Test-C Chorioallantoic Membrane model). This study was further extended by adding lomefloxacin dissolved in bovine vitreous (0.5 ml) on the chorioallantoic membrane (CAM). Using a standard scale, the phototoxic damage was assessed at different time intervals. Respective controls were kept in dark to distinguish the toxicity of the drugs per se. The results showed that the phototoxicity induced by lomefloxacin was very high followed by gatifloxacin and sparfloxacin and least for other drugs studied. Interestingly, lomefloxacin along with vitreous showed significantly low phototoxicity. This could be due to the antioxidant property of ascorbic acid present in the vitreous.     

Changes in protein profile of pigeonpea genotypes in response to NaCl and boron stress

Two pigeonpea [Cajanus cajan (L.) Millsp.] genotypes, a salt tolerant Manak and a salt sensitive ICPL 88039 were subjected to stress treatment of 3 mM boron, 60 mM NaCl and boron + NaCl at the seedling stage. Radicle and plumule proteins were analyzed by SDS-PAGE. Boron treatment increased 28.3 kDa proteins in plumule and 38.3 and 51.9 kDa proteins in radicle of Manak, however, there was no specific protein in ICPL 88039 either in plumule or in radicle. In NaCl treatment 95.6 kDa proteins appeared in plumule and 67.5 kDa proteins in radicle of Manak. Conversely content of some proteins decreased by boron treatment alone or in combination with NaCl although they were present in the controls. Thus, 54.3 kDa protein disappeared in ICPL 88039 plumule, 68.4 kDa in Manak radicle and 28.1 kDa in ICPL 88039 radicle.     

Microwave-promoted hydrolysis of plant seed gums on alumina support

Using a catalytic amount of potassium persulfate (1.48 x 10(-4)M), eight different seed gums were fully hydrolyzed on alumina support under microwave irradiation. The hydrolysis time varied between 1.33 and 2.33 min depending upon the seed gum structure. The used solid support could be easily separated from the hydrolyzates and recycled. However, under microwave field in an aqueous medium, the same amount of persulfate was unable to hydrolyze the seed gums. Solid-supported microwave hydrolysis has been compared with the microwave-enhanced aqueous hydrolysis (using K2S2O8 or 0.1N H2SO4) and also with the conventional hydrolysis procedures.