Janus kinase 3 regulates interleukin 2-induced mucosal wound repair through tyrosine phosphorylation of villin

Janus kinase 3 (Jak3) is a non-receptor tyrosine kinase known to be expressed in hematopoietic cells. Studies of whole organ homogenates show that Jak3 is also expressed in the intestines of both human and mice. However, neither its expression nor its function has been defined in intestinal epithelial enterocytes. The present studies demonstrate that functional Jak3 is expressed in human intestinal enterocytes HT-29 Cl-19A and Caco-2 and plays an essential role in the intestinal epithelial wound repair process in response to interleukin 2 (IL-2). Exogenous IL-2 enhanced the wound repair of intestinal enterocytes in a dose-dependent manner. Activation by IL-2 led to rapid tyrosine phosphorylation and redistribution of Jak3. IL-2-stimulated redistribution of Jak3 was inhibited by the Jak3-specific inhibitor WHI-P131. IL-2 also induced Jak3-dependent redistribution of the actin cytoskeleton in migrating cells. In these cells Jak3 interacted with the intestinal and renal epithelial cell-specific cytoskeletal protein villin in an IL-2-dependent manner. Inhibition of Jak3 activation resulted in loss of tyrosine phosphorylation of villin and a significant decrease in wound repair of the intestinal epithelial cells. Previously, we had shown that tyrosine phosphorylation of villin is important for cytoskeletal remodeling and cell migration. The present study demonstrates a novel pathway in intestinal enterocytes in which IL-2 enhances intestinal wound repair through mechanisms involving Jak3 and its interactions with villin.     

Preparation of cultured myofibers from larval salamander limbs for cellular plasticity studies

Identification of the mechanisms underlying cellular plasticity in salamander cells is important because these may give pointers to the restricted regenerative ability of mammals. The myofibers from salamanders are remarkable for their ability to undergo cellularization and cell-cycle re-entry during regeneration. Here, we describe a detailed method for the isolation and culture of larval salamander myofibers in numbers suitable for cellular plasticity studies. The basic protocol for isolation and purification of cells can be completed in 4 h.     

Alkaloid production in Vernonia cinerea: Callus, cell suspension and root cultures

Fast-growing callus, cell suspension and root cultures of Vernonia cinerea, a medicinal plant, were analyzed for the presence of alkaloids. Callus and root cultures were established from young leaf explants in Murashige and Skoog (MS) basal media supplemented with combinations of auxins and cytokinins, whereas cell suspension cultures were established from callus cultures. Maximum biomass of callus, cell suspension and root cultures were obtained in the medium supplemented with 1 mg/L alpha-naphthaleneacetic acid (NAA) and 5 mg/L benzylaminopurine (BA), 1.0 mg/L NAA and 0.1 mg/L BA and 1.5 mg/L NAA, respectively. The 5-week-old callus cultures resulted in maximum biomass and alkaloid contents (750 microg/g). Cell suspension growth and alkaloid contents were maximal in 20-day-old cultures and alkaloid contents were 1.15 mg/g. A 0.2-g sample of root tissue regenerated in semi-solid medium upon transfer to liquid MS medium containing 1.5 mg/L NAA regenerated a maximum increase in biomass of 6.3-fold over a period of 5 weeks. The highest root growth and alkaloid contents of 2 mg/g dry weight were obtained in 5-week-old cultures. Maximum alkaloid contents were obtained in root cultures in vitro compared to all others including the alkaloid content of in vivo obtained with aerial parts and roots (800 microg/g and 1.2 mg/g dry weight, respectively) of V. cinerea.     

Temporal changes in the growth, saponin content and antioxidant defense in the adventitious roots of Panax ginseng subjected to nitric oxide elicitation

Nitric oxide (NO) is a diffusible, gaseous signaling molecule. In plants, NO influences growth and development, and it can also affect plant responses to various stresses. Because NO induces root differentiation and interacts with reactive oxygen species, we examined the temporal effect of NO elicitation on root growth, saponin accumulation and antioxidant defense responses in the adventitious roots of mountain ginseng (Panax ginseng). The observations revealed that NO is involved in root growth and saponin production. Elicitation with sodium nitroprusside (SNP) activated O₂ ⁻-generating NADPH oxidase (NOX) activity, which most probably subsequently enhanced growth of adventitious roots of mountain ginseng. A severe inhibition of NOX activity and decline in dry weight of SNP elicited adventitious roots in the presence of NOX inhibitor (diphenyl iodonium, DPI), which further supports involvement of NOX in root growth. Enhanced activities of antioxidant enzymes by SNP appear to be responsible for low H₂O₂, less lipid peroxidation, and modulation of ascorbate and non-protein thiol statuses in the adventitious roots of mountain ginseng. Dry mass, saponin content and NOX activity was related with NO content present in adventitious roots of mountain ginseng.     

Indian Biotech Bazaar: a swot analysis

Biotechnology is a life science-based technique especially used in agriculture, medicine and food sciences. It is generally defined as the manipulation in organisms to generate products for the welfare of the world. Biotechnology combines disciplines such as genetics, biochemistry, microbiology, and cell biology along with information technology, chemical engineering, robotics etc. It includes basic industries such as food processing, tissue culture, plant development and other sophisticated ones such as recombinant therapeutics and diagnostics. Biotechnology, globally recognized as a rapidly emerging and far-reaching technology, is aptly described as the "technology of hope" for its promise of food, health and environmental sustainability. In India, biotechnology employs more than 10 000 people and generates roughly US$ 500 million in revenue annually. The biotechnology market has increased its sales from Rs. 50 billion in 1997 to Rs.70 billion in 2000, and is expected to cross Rs. 240 billion by the year 2010. In India, the human health biotech products account for 60% of the total market; agribiotech and veterinary 25%, medical devices, contract research and development (R&D), reagents and supplies constitute the remaining 15% Moreover, to facilitate foreign investment, capital and government policies are being revised. Other important industries include industrial enzyme manufacture, bioinformatics, and medical devices. Biotechnology has had limited appeal so far on our capital markets, and we have less then a dozen biotech companies listed on the public markets.     

Sucrose-inducible expression of hepatitis B surface antigen using potato granule-bound starch synthase promoter

NT-1 cells of tobacco (Nicotiana tabacum L.) were transformed with pGBSSHBS and pGBSSHER expression cassettes wherein expression of hepatitis B surface antigen (HBsAg) was driven by potato granule-bound starch synthase (GBSS) promoter. The transformed nature of the cells was confirmed by PCR analysis. Expression of HBsAg was confirmed by RT-PCR and Western blotting and levels of expression were assayed by ELISA. Transformed cell lines exhibited a sucrose-inducible pattern of HBsAg expression. NT-1 medium supplemented with 175 mmol L⁻¹ sucrose gave the highest HBsAg expression of 198 ng g⁻¹ FW after 8 days of induction. Different sugars, for example glucose, fructose, and palatinose, were also tested to study the inducible nature of GBSS promoter. The results demonstrate that potato GBSS promoter can be used in heterologous host systems like tobacco NT-1 cell suspension cultures for sucrose-inducible expression of recombinant proteins.     

Single feature polymorphism discovery in rice

The discovery of nucleotide diversity captured as single feature polymorphism (SFP) by using the expression array is a high-throughput and effective method in detecting genome-wide polymorphism. The efficacy of such method was tested in rice, and the results presented in the paper indicate high sensitivity in predicting SFP. The sensitivity of polymorphism detection was further demonstrated by the fact that no biasness was observed in detecting SFP with either single or multiple nucleotide polymorphisms. The high density SFP data that can be generated quite effectively by the current method has promise for high resolution genetic mapping studies, as physical location of features are well-defined on rice genome.     

Neural induction from ES cells portrays default commitment but instructive maturation

The neural induction has remained a debatable issue pertaining to whether it is a mere default process or it involves precise instructive cues. We have chosen the embryonic stem (ES) cell model to address this issue. In a devised monoculture strategy, the cell-cell interaction availed through optimum cell plating density could define the niche for the attainment of efficient in vitro neurogenesis from the ES cells. The medium plating density was found ideal in generating optimum number of progenitors and also yielded about 80% mature neurons in a serum free culture set up barring any exogenous inducers. We could also demarcate and quantify the neural stem cells/progenitors among the heterogeneous cell population of differentiating ES cells using nestin intron II driven EGFP expression as a tool. The one week post-plating was determined to be the critical time window for optimum neural progenitor generation from ES cells that helped us further in purifying these cells and in demonstrating their proliferation and multipotent differentiation potential. Seeding cells at varying densities, we could decipher an interesting paradoxical scenario that interlinked both commitment and maturation with the initial plating density having a vital influence on neuronal maturation but not specification and the secretory factors were apparently playing a key role during this process. Thus it was comprehended that, the neural specification was a default process independent of exogenous factors and cellular interaction. Conversely, a defined number of cells at the specification stage itself seemed critical to provide an auto-/paracrine means of signaling threshold for the maturation process to materialize.