3,5-bis(phenylmethylene)-1-(N-arylmaleamoyl)-4-piperidones: a novel group of cytotoxic agents

A series of novel 3,5-bis(phenylmethylene)-1-(N-arylmaleamoyl)-4-piperidones 3 have been synthesized which displayed potent cytotoxicity towards human Molt 4/C8 and CEM T-lymphocytes as well as murine P388 and L1210 leukemic cells. In contrast, the related N-arylmaleamic acids 4 possessed little or no cytotoxicity in these four screens. Molecular modeling revealed certain interplanar and bond angles and interatomic distances which were perceived to contribute to the observed bioactivity as well as providing suggestions for future structural modifications of the piperidones 3. Evaluation of representative compounds in series 3 and 4 on the activity of human N-myristoyltransferase revealed that, at the maximum concentration utilized, namely 250 microM, only weak inhibiting properties were displayed by some of the compounds in series 4. Various members of series 3 and 4 were well tolerated in mice.     

Induction of hepatic antioxidants in freshwater catfish (Channa punctatus Bloch) is a biomarker of paper mill effluent exposure

Enzymatic and non-enzymatic antioxidants serve as an important biological defense against environmental oxidative stress. Information on antioxidant defense in fish is meager despite that fish are constantly exposed to a myriad of environmental stress including the oxidants. This study, therefore, assesses the activities of antioxidant enzymes viz., glutathione peroxidase, catalase and glutathione S-transferase and the non-enzymatic antioxidants viz., glutathione and metallothionein in various tissues of freshwater fish Channa punctatus (Bloch), in response to short-term and long-term exposures to paper mill effluent. The fish were exposed to the effluent at a concentration of 1.0% (v/v) for 15, 30, 60 and 90 days. The exposure caused a time-dependent increase in glutathione level (P < 0.001), activities of glutathione peroxidase (P < 0.05 to P < 0.001), glutathione S-transferase (P < 0.001) and a marginal initial decrease in catalase activity in the liver (P < 0.01 to P < 0.001). Metallothionein was induced in liver after 60 days of exposure. Two isoforms of metallothionein were detected. Catalase activity also increased 60 days afterwards. Antioxidant pattern was different in gill and kidney showing that liver was more resistant to oxidative damage as compared to gills and kidney. Our results demonstrate a pollutant-induced adaptive response in fish. In addition, levels of enzymatic and non-enzymatic tissue antioxidants may serve as surrogate markers of exposure to oxidant pollutants in fish.     

Establishment of forskolin yielding transformed cell suspension cultures of Coleus forskohlii as controlled by different factors

Suspension cultures derived from gall calli which were obtained following infection with Agrobacterium tumefaciens (C58) were established in Coleus forskohlii. Cell line selection following single cell cloning or cell aggregate cloning was carried out to select cell lines capable of fast growth and for producing high level of forskolin. A fast growing cell line (GSO-5/7) thus selected was found to accumulate 0.021% forskolin in 42 days. The effect of cultural conditions on cell growth was studied to identify factors influencing biomass yield. Cell growth in suspension was found to be influenced significantly by carbon source, initial cell density and light or dark condition. Optimal cell growth (20 fold increase in biomass in a 42 day period) was obtained when the cells were grown in dark condition in B5O media containing 3% sucrose as sole carbon source with an initial cell density of 1.5 x 10(5) cells per ml. Forskolin accumulation was maximum (0.021%) in the stationary phase of cell growth. These suspension cultures showed continuous and stable production of forskolin.     

Ultrastructure of spermatozoa correlated with phylogenetic relationship between Heteropneustes fossilis and Rana tigrina

A study using transmission electron microscopy (TEM) of the spermatozoa of Rana tigrina and Heteropneustes fossilis in all phases of the annual reproductive cycle revealed that there was a phylogenetic relationship between them. The spermatozoa of H. fossilis appeared horseshoe-shaped, somewhat oval or wedge-shaped at the anterior end and broader at the posterior end. The horseshoe-shaped spermatozoan nucleus was observed during spermiogenesis of R. tigrina but later changed into a finger shape at maturity. The posterior end of the nuclei of mature spermatozoa of R. tigrina was blunt. The extremely dense homogenized nucleus was capped with an acrosomal vesicle in both species suggesting a definite phylogenetic inter-relationship between them.     

Embryogenesis and plant regeneration from callus cultures derived from unpollinated ovaries of Hyoscyamus muticus L.

Unpollinated ovaries of Hyoscyamus muticus L. (commonly known as Egyptian henbane) were cultured on Murashige and Skoog and Bourgin and Nitsch media supplemented with various growth hormones to study the organogenesis, embryogenesis and regeneration of plantlets. Embryogenesis was reported for callus grown on both media containing 0.05 mg/l α-naphthaleneacetic acid and 0.5 mg/l 6-benzylaminopurine. Differentiation of roots and shoots from the calli also occurred in these media. Albinism or chlorophyll deficiency and variation in ploidy level were observed among the ovary-derived plantlets. Received: 7 April 1997 / Revised received: 2 August 1997 / Accepted: 2 September 1997     

Propagation of Dalbergia sissoo Roxb. through in vitro shoot proliferation from cotyledonary nodes

A protocol is presented for micropropagation of an economically important timber-yielding forest tree, Dalbergia sissoo Roxb. (Sissoo). Multiple shoots were induced from cotyledonary nodes derived from 1-week-old axenic seedlings on Murashige and Skoog's medium containing either N ⁶-benzyladenine (BA), kinetin (Kn), isopentenyladenine (2iP) or thidiazuron (TDZ), with BA being the most effective growth regulator. High-frequency shoot proliferation (99%) and maximum number of shoots per explant (7.9 shoots) were recorded with BA at an optimum level of 8.9 μM. Concentrations of all cytokinins tested above the optimum level markedly reduced the frequency of shoot proliferation. A proliferating shoot culture was established by repeatedly subculturing the original cotyledonary node on shoot multiplication medium after each harvest of the newly formed shoots. Primary shoots were multiplied as nodal explants, and from each stem node 2 or 3 shoots developed. Thus, 60–70 shoots were obtained in 3 months from a single cotyledonary node. About 91% of the shoots developed roots following transfer to half-strength MS medium containing a combination of 5.7 μM indole-3-acetic acid, 4.9 μM indole-3-butyric acid and 5.3 μM indole-3-propionic acid. Eighty percent of the plantlets were successfully acclimatized and established in soil. Received: 1 October 1997 / Revision received: 31 March 1998 / Accepted: 7 April 1998     

Rapid In Vitro Propagation of East Indian Rosewood (Dalbergia latifolia Roxb.) through High Frequency Shoot Proliferation from Cotyledonary Nodes

An efficient protocol is described for large scale in vitro propagation of east Indian rosewood (Dalbergia latifolia Roxb.) using cotyledonary nodes derived from axenic seedlings. Of the four different cytokinins tested, BA was most effective in inducing multiple shoot buds in the explants. High frequency shoot proliferation (93%) coupled with maximum number of shoot formation (10-12 shoots/explant) was recorded on Murashige and Skoog’s medium supplemented with 2.0 mg/l BA. The frequency of shoot proliferation declined at higher levels of cytokinins. Shoot culture was multiplied by subculturing the original cotyledonary node on a fresh shoot multiplication medium each time aHer excising the newly formed shoots. Shoots obtained from each passage were multiplied further as nodal explants and each node produced 3-4 shoots. In two months from a single cotyledonary node, about 90 shoots were obtained. Rooting was induced in 72% of the regenerated shoots on half-strength MS containing IAA, IBA and IPA each at 1.0 mg/l. Rooted plantlets were hardened off and eventually established in soil.     

Rapid vegetative multiplication in Colocasia esculenta (L) Schott (taro)

Initial multiplication of taro was achieved by dividing corms into pieces, each with several buds, and planting them in sterile potting mix. Surface planting and decapitation of the new primary meristem on each sucker forced additional shoot meristems to grow. Meristems of six cultivars were cultured on a modified Murashige and Skoog medium plus TDZ. In experiments with the cultivar Niue, explants cultured on modified MS medium plus 2.6 μM (0.6 mg L^-1 TDZ grew more vigorously than on media including BA. Transfer to 4.3 μM (1.0 mg L^-1 TDZ subsequently gave a 15–25 fold increase in production of plantlets per four week culture period compared to four-fold with BAP. The two stage propagation technique described in this paper is an efficient way to produce taro plants for commercial planting or the production of pathogen-tested material. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vivo and in vitro measurement of cell mediated immunity in Marek's disease: role of reticuloendothelial system

Dinitrofluorobenzene (DNFB) contact-sensitivity test and leucocyte adherence inhibition (LAI) test were performed in this study as in vivo and in vitro tests to measure the cell-mediated immunity (CMI) in chickens subjected to stimulation of reticuloendothelial (RE) system, depletion of RE system and other experimental groups after being challenged with Marek's disease (MD) virus. It was found that CMI was lower in the birds with depleted RE system and infected control birds, whereas CMI was higher in the birds with activated RE system and vaccinated birds as revealed by DNFB contact-sensitivity test. In cases of LAI test, the number of LAI-positive birds were highest in the chicks with depleted RE system particularly in 3rd and 4th month of age, when the incidence of MD was also maximum.     

Design,parallel synthesis,and crystal structures of biphenyl antithrombotics as selective inhibitors of tissue factor FVIIa complex. Part 1: Exploration of S2 pocket pharmacophores

Factor VIIa (FVIIa), a serine protease enzyme, coupled with tissue factor (TF) plays an important role in a number of thrombosis-related disorders. Inhibition of TF·FVIIa occurs early in the coagulation cascade and might provide some safety advantages over other related enzymes. We report here a novel series of substituted biphenyl derivatives that are highly potent and selective TF·FVIIa inhibitors. Parallel synthesis coupled with structure-based drug design allowed us to explore the S2 pocket of the enzyme active site. A number of compounds with IC₅₀ value of <10 nM were synthesized. The X-ray crystal structures of some of these compounds complexed with TF·FVIIa were determined and results were applied to design the next round of inhibitors. All the potent inhibitors were tested for inhibition against a panel of related enzymes and selectivity of 17,600 over thrombin, 450 over trypsin, 685 over FXa, and 76 over plasmin was achieved. Two groups, vinyl 36b and 2-furan 36ab, were identified as the optimum binding substituents on the phenyl ring in the S2 pocket. Compounds with these two substituents are the most potent compounds in this series with good selectivity over related serine proteases. These compounds will be further explored for structure–activity relationship.