Showing papers by "Department of Biotechnology published in 2002"
TL;DR: This review details the various facets of biotechnology of B. braunii, including its microbiology and physiology; production of hydrocarbons and other compounds by the alga; methods of culture; downstream recovery and processing of algal hydrocarols; and cloning of the algal genes into other microorganisms.
Abstract: Botryococcus braunii, a green colonial microalga, is an unusually rich renewable source of hydrocarbons and other chemicals. Hydrocarbons can constitute up to 75% of the dry mass of B. braunii. This review details the various facets of biotechnology of B. braunii, including its microbiology and physiology; production of hydrocarbons and other compounds by the alga; methods of culture; downstream recovery and processing of algal hydrocarbons; and cloning of the algal genes into other microorganisms. B. braunii converts simple inorganic compounds and sunlight to potential hydrocarbon fuels and feedstocks for the chemical industry. Microorganisms such as B. braunii can, in the long run, reduce our dependence on fossil fuels and because of this B. braunii continues to attract much attention.
742 citations
TL;DR: Recent applications of CDs in pharmaceuticals with a major emphasis on drug delivery systems are described and the utility of these water-soluble cyclic glucans in a variety of foods, flavors cosmetics, packaging and textiles is elaborated.
451 citations
TL;DR: This review attempts to describe in detail the three major classes of nitrile-converting enzymes, namely nitrilases,Nitrile hydratases and amidases, including their occurrence, mechanism of action, characteristics and applicability in different sectors.
Abstract: Nitrile-converting enzymes are becoming commonplace in the synthesis of pharmaceuticals and commodity chemicals. These versatile biocatalysts have potential applications in different fields including synthetic biocatalysis and bioremediation. This review attempts to describe in detail the three major classes of nitrile-converting enzymes, namely nitrilases, nitrile hydratases and amidases. Various aspects of these enzymes including their occurrence, mechanism of action, characteristics and applicability in different sectors have been elaborately elucidated. Cloning of genes related to nitrile-converting enzymes is also discussed.
403 citations
TL;DR: Results showed that high levels of LEA3 accumulation in the leaves of transgenic Pusa Basmati 1 rice plants might have conferred the significant increase in tolerance against drought and salt stress.
157 citations
TL;DR: The effect of metformin on glucose uptake corresponded to p38 MAPK activation, which suggests the potential role p38 in glucose uptake and demonstrates the direct insulin sensitizing action of met formin on skeletal muscle cells.
Abstract: 1 Metformin lowers blood glucose levels in type 2 diabetic patients. To evaluate the insulin sensitizing action of metformin on skeletal muscle cells, we have used C2C12 skeletal muscle cells differentiated in chronic presence or absence of insulin. 2 Metformin was added during the last 24 h of differentiation of the C2C12 myotubes. Insulin-stimulated tyrosine phosphorylation of insulin receptor (IR) and insulin receptor substrate-1 (IRS-1) was determined. 3 Chronic insulin treatment resulted in 60 and 40% reduction in insulin-stimulated tyrosine phosphorylation of IR and IRS-1, respectively. Treatment with metformin was able to increase the tyrosine phosphorylation of IR and IRS-1 by 100 and 90% respectively. 4 Chronic insulin treatment drastically reduced (45%) insulin-stimulated phosphatidyl inositol 3-kinase (PI 3-kinase) activity. Metformin treatment restored PI 3-kinase activity in insulin-resistant myotubes. 5 Insulin-stimulated glucose uptake was impaired in chronically insulin-treated myotubes. Metformin increased basal glucose uptake to significant levels (P<0.05), but metformin did not increase insulin-stimulated glucose transport. 6 All the three mitogen-activated protein kinases (MAPK) were activated by insulin in sensitive myotubes. The activation of p38 MAPK was impaired in resistant myotubes, while ERK and JNK were unaffected. Treatment with metformin enhanced the basal activation levels of p38 in both sensitive and resistant myotubes, but insulin did not further stimulate p38 activation in metformin treated cells. 7 Treatment of cells with p38 inhibitor, SB203580, blocked insulin- and metformin-stimulated glucose uptake as well as p38 activation. 8 Since the effect of metformin on glucose uptake corresponded to p38 MAPK activation, this suggests the potential role p38 in glucose uptake. 9 These data demonstrate the direct insulin sensitizing action of metformin on skeletal muscle cells.
122 citations
TL;DR: The toxic metal contents in seeds were found positively correlated with the ambient concentration of metals in water and sediments and the importance of these findings has been discussed for national water resource economy of the country and human health perspectives.
83 citations
TL;DR: A strain of Bacillus coagulans RCS3 isolated from ahot‐water spring produced significant β‐galactosidase activity at 10 days of growth in a flask, suggesting that 63 °C is the temperature of preference compared with 65 °C for a combination of good activity and stability.
Abstract: A strain of Bacillus coagulans RCS3 isolated from a hot-water spring produced significant beta-galactosidase activity at 10 days of growth in a flask. While enzyme production was maximum at 50 degrees C, the highest activity was at 65 degrees C, where the half-life was 2 h. A 2 degrees C decrease in temperature increased the half-life to 15 h without significantly changing the activity, suggesting that 63 degrees C is the temperature of preference compared with 65 degrees C for a combination of good activity and stability. The beta-galactosidase was also stable over pH 5-8, with peak activity at pH 6-7. It was strongly and competitively inhibited by the hydrolysis product galactose. Bivalent cations (Cu(2+), Ni(2+) and Hg(2+)) in the concentration range of 0.5-2.0 mM also inhibited enzyme activity. Both lactose solution and whey could be hydrolysed substantially within 36 h at 50 degrees C. The thermostability and pH-stability and good hydrolytic capability make this enzyme potentially useful in the dairy industry.
64 citations
TL;DR: It was found that a long selection period with the low hygromycin concentration yielded stable transformants, which was further confirmed by PCR analysis and Southern hybridization of transformants.
54 citations
TL;DR: Callus cultures derived from internodal segments of two cultivars of carnation susceptible to Fusarium oxysporum f.sp.
Abstract: Callus cultures derived from internodal segments of two cultivars of carnation susceptible to Fusarium oxysporum f.sp. dianthi were successfully used for in vitro selection for resistance to this pathogenic fungus. Resistant lines were selected by culturing calli on growth medium containing various concentrations of the culture filtrate of F. oxysporum f.sp. dianthi. Resistant calli obtained after two cycles (25 days/cycle) of selection were used for plant regeneration. About 32% of the plants regenerated from the resistant calli had acquired considerable resistance against the pathogen in the field. No phenotypic variation was observed in the selected regenerates.
54 citations
TL;DR: 34 random primers were studied to identify sex in kiwifruit and eight sex-linked markers were identified and a dendrogram has been developed using the UPGMA method to detail the genetic control of dioecy in several species.
52 citations
TL;DR: In vitro shoots of Spilanthes acmella Murr induced from hypocotyl segments obtained from 1-week-old seedlings on Murashige and Skoog's medium containing benzyladenine, isopentenyl adenine, and naphthaleneacetic acid showed normal flowering without any morphological variation.
Abstract: Multiple shoots of Spilanthes acmella Murr. were induced from hypocotyl segments obtained from 1-week-old seedlings on Murashige and Skoog's (MS) medium containing benzyladenine (BA), isopentenyl adenine, and naphthaleneacetic acid (NAA). High frequency shoot proliferation (95 %) and maximum number of shoots per explant (10 ± 0.6) were recorded with 0.5 mg dm−3 BA in combination with 0.1 mg dm−3 NAA. A proliferation was achieved by repeatedly subculturing the nodal segments on shoot multiplication medium. About 95 % of the in vitro shoots developed roots after transfer to half strength MS medium containing indole-3-butyric acid (1.0 mg dm−3). 95 % of the plantlets were successfully acclimatized and established in soil. Transplanted plantlets showed normal flowering without any morphological variation.
TL;DR: It is concluded that ERK-1/-2 and p38 MAP kinase cascades oppositely regulate each other's function(s) thereby regulating L6E9 skeletal muscle differentiation.
Abstract: Role of mitogen activated protein kinases (MAPK) in skeletal muscle differentiation is not fully understood. We investigated subtype-specific functions and their interactions, if any, in the regulation of myogenic differentiation in L6E9 skeletal muscle cells. We show inhibition of extracellular signal-regulated kinase-1 and -2 (ERK-1/-2) and activation of p38 MAP kinase during the differentiation of L6E9 rat skeletal muscle cells under low serum condition. Inhibition of ERK-1/-2 activity dramatically enhanced differentiation as was evident from cellular morphology, expression of muscle differentiation specific marker proteins, suggesting that ERK-1/-2 activation may be inhibitory to initiation and progression of differentiation. In contrast, inhibition of p38 MAP kinase completely prevented differentiation; meaning p38 activation is required from the initiation till terminal differentiation of L6E9 cells. Moreover, inhibition of ERK-1/-2 activities enhanced the activation of p38 MAP kinase that resulted in enhancement of differentiation; whereas inhibition of p38 MAP kinase activity enhanced the ERK-1/-2 activities culminating in abrogation of differentiation. We conclude that ERK-1/-2 and p38 MAP kinase cascades oppositely regulate each other's function(s) thereby regulating L6E9 skeletal muscle differentiation.
TL;DR: It is reported for the first time that the differential regulation of FAK tyrosine phosphorylation by insulin during skeletal muscle differentiation is modulated by insulin.
Abstract: Focal adhesion kinase (FAK) was heavily phosphorylated as a function of differentiation of C2C12 mouse skeletal muscle cells. Insulin caused increases in FAK phosphorylation before stabilization in proliferated cells, while in differentiated cells there was a consistent transient inhibition of FAK phosphorylation before stimulation. The expression level of FAK was unaltered. Specific inhibition of insulin receptor tyrosine kinase activity abolished the insulin-mediated dephosphorylation of FAK. The data strongly indicate that FAK tyrosine phosphorylation, necessary for skeletal muscle differentiation, is modulated by insulin. Thus, for the first time, we report the differential regulation of FAK tyrosine phosphorylation by insulin during skeletal muscle differentiation.
TL;DR: It is proposed that PKC downregulation results in enhanced tyrosine phosphorylation of FAK, Cas, and paxillin, thus promoting the establishment of Cas-CrkII complex, leading to activation of JNK and that these interactions are dependent upon the integrity of actin cytoskeleton during muscle cell differentiation.
TL;DR: It is proposed that gliclazide can regulate part of the insulin signaling in insulin-resistant skeletal muscle, and p38 could be a potential therapeutic target for glucose uptake to treat insulin resistance.
Abstract: Sulfonylurea drugs are used in the treatment of type 2 diabetes. The mechanism of action of sulfonylureas is to release insulin from pancreatic cells and they have been proposed to act on insulin-sensitive tissues to enhance glucose uptake. The goal of the present study was to test the hypothesis that gliclazide, a second-generation sulfonylurea, could enhance insulin signaling in insulin-resistant skeletal muscle cells. We demonstrated that gliclazide enhanced insulin-stimulated insulin receptor tyrosine phosphorylation in insulin-resistant skeletal muscle cells. Although insulin receptor substrate-1 tyrosine phosphorylation was unaffected by gliclazide treatment, phosphatidylinositol 3-kinase activity was partially restored by treatment with gliclazide. No increase in 2-deoxyglucose uptake in insulin-resistant cells by treatment with gliclazide was observed. Further investigations into the mitogen-activated protein kinase (MAPK) pathway revealed that insulin-stimulated p38 phosphorylation was impaired, as compared with extracellular-signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), which were phosphorylated normally in insulin-resistant cells. Treatment with gliclazide could not restore p38 phosphorylation in insulin-resistant cells. We propose that gliclazide can regulate part of the insulin signaling in insulin-resistant skeletal muscle, and p38 could be a potential therapeutic target for glucose uptake to treat insulin resistance.
TL;DR: The results of this study suggest that it is possible to develop clones of genetically superior trees of R. pseudoacacia and G. optiva for use in agroforestry or afforestation programmes.
Abstract: Rapid vegetative propagation of promising multipurpose trees is an important need in agroforestry development. Grewia optiva andRobinia pseudoacacia are two such species, about the propagation of which very little is known. The rooting ability of stem cuttings harvested from juvenile (2 year-old) and mature hardwood(15 year-old) trees of Robinia pseudoacacia andGrewia optiva was significantly influenced by the period or season of harvesting cutting. Juvenile cuttings of both species rooted significantly better (42.9% in R. pseudoacacia and 46.6% in G. optiva) than mature hardwood cuttings (34.7% in R.pseudoacacia and 41.4% in G. optiva). The effect was more pronounced in auxin treated cuttings. InR. pseudoacacia, the highest rooting in juvenile(83.3%) and mature (66.6%) cuttings prepared in spring season was observed with the NAA (500 mg/l) treatment. InG. optiva, IBA (250 mg/l) in the monsoon season was most effective and recorded a maximum of 80% and 70%rooting in juvenile and mature cuttings, respectively. The auxin treatments also significantly enhanced the number of roots (23.8 inR. pseudoacacia and 17.6 in G.optiva) and their mean length (14.3 cm inR. pseudoacacia and 16.1 cm inG. optiva). Interactions between age, season and treatments were significant at P < 0.05 level for rooting percent in R. pseudoacacia and non-significant for G. optiva. The results of this study suggest that it is possible to develop clones of genetically superior trees of R. pseudoacacia and G.optiva for use in agroforestry or afforestation programmes.
TL;DR: In vitro and in vivo activities against chloroquine sensitive and resistant Plasmodium falciparum strains and four series of ring-substituted-L-histidines and histamines are reported.
TL;DR: FAK, PI 3‐kinase, and MAP kinase are important components of pathway(s) that regulate insulin stimulated muscle cell spreading that are supported by increased phosphotyrosine accumulation on focal adhesions and increased membrane localization of FAK after stimulation by insulin.
Abstract: Insulin plays an important role in muscle cell survival and proliferation. However, there is no report showing the role of insulin in spreading of muscle cells. In the present report, we showed that insulin enhances muscle cell spreading concomitant with enhanced tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin. Moreover, insulin can stimulate the cell spreading even in presence of integrin a5 blockers although to a lesser extent as compared to control. Cell adhesion was not dependent on insulin and serum, and decreased in presence of integrin blockers. We found direct association of FAK with affinity purified insulin receptors using in vitro kinase assay. The increase in FAK tyrosine phosphorylation was associated with increase in its kinase activity and further supported by increased phosphotyrosine accumulation on focal adhesions and increased membrane localization of FAK after stimulation by insulin. Moreover, insulin-mediated muscle cell spreading was dependent upon phosphatidylinositol 3-kinase (PI 3-kinase) activity. PI 3-kinase activity was found to be associated with FAK and the FAK associated PI 3-kinase activity enhanced when cells were plated in presence of insulin. We also observed activation of MAP kinases, i.e., ERK-1/-2 during insulin mediated muscle cell spreading. In conclusion, FAK, PI 3-kinase, and MAP kinase are important components of pathway(s) that regulate insulin stimulated muscle cell spreading. J. Cell. Physiol. 193: 187-198, 2002.
TL;DR: This review describes the basic structure of microtubules and its dynamics in general, with specific insights into leishmanialmicrotubules, the salient features of micro Tubule–drug interactions including the specificity of certain drugs for parasitic micro Tubules.
Abstract: Microtubules are cytoskeletal polymers essential for the survival of all eukaryotes. These proteins are the proposed cellular targets of many anticancerous, antifungal and antihelminthic drugs. Sufficient differences exist between the microtubules of kinetoplastid parasites like Leishmania and humans to explore the selective targeting of these proteins for therapeutic purposes. This review describes the basic structure of microtubules and its dynamics in general, with specific insights into leishmanial microtubules, the salient features of microtubule-drug interactions including the specificity of certain drugs for parasitic microtubules. Chemotherapy against leishmanial parasites is failing because of the emergence of drug resistant strains. The possible mechanisms of resistance to antimicrotubule agents along with insights into the role of microtubules in mediating drug resistance in Leishmania are discussed.
TL;DR: Data suggest that ERK‐1/‐2 and p38 MAPK activities modulate Elk‐1 expression and activation to regulate skeletal muscle differentiation.
TL;DR: Data suggest that the β- and γ-tubulin expression and the response to paclitaxel is affected due to arsenite resistance.
Abstract: Differentiation of Leishmania donovani promastigotes into infectious amastigotes is accompanied by differential tubulin gene expression Tubulin is one of the proposed targets of clinically useful antileishmanial agents and its expression is known to alter due to drug resistance In this study, β- and γ-tubulin expression under various stages of differentiation was measured in an in vitro generated arsenite-resistant L donovani strain Results showed higher constitutive expression of β-tubulin in the arsenite-resistant promastigotes and amastigotes compared with the wild-type β-Tubulin expression in the resistant promastigotes increased on paclitaxel treatment Significant differences in γ-tubulin expression were observed only between the amastigotes, but not between promastigotes, of wild-type and resistant strains Paclitaxel did not produce any significant change in the expression profile of γ-tubulin in either of the strains, neither before nor after differentiation Data suggest that the β- and γ-tubulin expression and the response to paclitaxel is affected due to arsenite resistance
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TL;DR: A strain of Clostridium botulinum type E has been isolated from soil samples of Gwalior, India and shows curved vegetative cells with oval, bulging, and terminal spores.
Abstract: A strain of Clostridium botulinum type E has been isolated from soil samples of Gwalior, India. The isolated strain shows curved vegetative cells with oval, bulging, and terminal spores. The production of toxin was detected by immunodiffusion test, symptomatic death of mice and mouse protection assay with trivalent antitoxin (A+B+E). The culture supernatant gave 10(3) MLD (minimum lethal dose) per ml without any protease treatment. Group specific and serotype specific primers amplified the DNA fragments of 260 bp and 445 bp, respectively, indicating Clostridium botulinum type 'E.'
TL;DR: Results show for the first time that, in skeletal muscle, stress caused by arsenite involves the MAP-kinase signal transduction cascade, perhaps in a cell type-specific regulatory pathway.
Abstract: We studied the activation of MAPKs, such as ERK and JNK, by arsenite in C2C12 mouse skeletal muscle cells as a function of proliferation and differentiation. Data showed that both ERK and JNK were activated by arsenite in proliferated and differentiated cells in a differential manner. The activation of the enzymes was not due to alteration in their concentration. The activities were independent of each other. ERK activation was possibly partly through the activity of Ras, Raf and the MEK cascade, and due to oxidative stress, which possibly led to the activation of the transcription factor, Elk-1. In contrast, the activation of JNK was solely due to the generation of free radicals, resulting in activation of c-Jun and perhaps Elk-1. These results show for the first time that, in skeletal muscle, stress caused by arsenite involves the MAP-kinase signal transduction cascade, perhaps in a cell type-specific regulatory pathway.
TL;DR: This study evaluated the efficiency of callus induction and plantlet regeneration from mature cotyledonary segments of groundnut cultivars VRI-2 andVRI-3 using NAA and IAA in combination with KIN or BAP and the resulting plantlets were rooted with IBA and NAA.
Abstract: We evaluated the efficiency of callus induction and plantlet regeneration from mature cotyledonary segments of groundnut cultivars VRI-2 and VRI-3. Callus cultures were induced from mature tissues using NAA and IAA in combination with KIN or BAP. Maximum induction was recorded with 3.0 mg/L IAA and 1.0 mg/L BAP. However, green, compact, and nodular calli were obtained in 2.5 mg/L of IAA or NAA combined with 1.0 mg/L of either BAP or KIN. Fresh and dry weights were highly influenced by auxin concentration. Compact and nodular calli were then transferred to shoot induction media. The highest mean number of shoots was observed in 3.0 mg/L BAP plus 0.5 mg/L IAA. Finally, the resulting plantlets were rooted with IBA and NAA.
TL;DR: The role of PKC during insulin mediated muscle cell spreading was investigated and it was found that PKC-α becomes active and localise to membrane during insulinmediated cell spreading and PKC activation is essential for cell spreading stimulated by insulin.
Abstract: Protein kinase C (PKC) is known to play important roles in integrin mediated cell spreading. This study investigated the role of PKC during insulin mediated muscle cell spreading, which was independent of integrin alpha5. We found that PKC-alpha becomes active and localise to membrane during insulin mediated cell spreading. We also found that PKC activation is essential for cell spreading stimulated by insulin and this activation enhances the cell spreading. PKC activation increased the tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin as well as tyrosine kinase activity of FAK. We also observed that PKC activation enhanced the FAK associated PI 3-kinase activity and also increased the activation of ERK-1/-2. Moreover, the effect of PKC activation on insulin mediated cell spreading as well as tyrosine phosphorylation of FAK and paxillin depends upon integrity of actin cytoskeleton. Thus, PKC is an important signaling protein during insulin mediated muscle cell spreading.
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TL;DR: A successful protocol for meristem tip culture to eliminate carnation latent virus from carnation cv.
Abstract: A successful protocol for meristem tip culture to eliminate carnation latent virus from carnation cv. scania has been described . The virus was found to be mechanically transmissible to Chenopodium quinoa, C. amaranticolor, Dianthus barbatus and Saponaria vaccaria. Murashige and Skoog'smedium (MS) supplemented with NAA (1.0 microM) and Kn (20.0 microM) proved best for meristem establishment and microshoots were rooted in MS medium supplemented with IBA (5.0 microM). Meristems measuring 0.1 and-0.2 mm yielded virus free plants and larger meristems were not effective.
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TL;DR: Two primer sequences were found to be closely linked to the locus for disease resistance in sorghum, which was found to segregate as a simple recessive trait in a cross to susceptible cultivar HC136.
Abstract: Anthracnose caused by Colletotrichum graminicola is one of the major diseases of sorghum. The locus for disease resistance in sorghum [Sorghum biocolor (L.) Moench] accession G73 was found to segregate as a simple recessive trait in a cross to susceptible cultivar HC136. In order to identify molecular markers linked to the locus for disease resistance, random amplified polymorphic DNA (RAPD) analysis was coupled with bulk segregant analysis. DNA from the parental cultivars and the bulks were, screened by PCR amplification with 114 RAPD primers. Three RAPD primers amplified a sequence that consegregated with the recessive resistance allele, while another three amplified a band linked to the susceptible allele. The six disease linked markers were screened with individual resistant and susceptible genotypes to observe degree of linkage of identified RAPD markers with the gene for resistance. Two primer sequences (OPI 16 and OPD 12) were found to be closely linked to the locus for disease resistance.
TL;DR: Evidence regarding tyrosine phosphorylation of myosin heavy chain, evidence that insulin can phosphorylate myos in association with Csk, a signalling molecule, modulation of this association by insulin, and evidence that these interactions are associated with skeletal muscle differentiation are presented.
TL;DR: From the literature cited, it is evident that kiwifruit is highly amenable for in vitro studies as various explants have been favourably found to respond to different culture media with different types and concentrations of growth regulators.
Abstract: SummaryKiwifriut has gained enormous popularity in the past two decades in many countries of the world and is in great demand due to its nutritional and medicinal value. For commercialization of this crop and to meet the growing demand for planting material, tissue and organ culture techniques are being used as alternative methods for propagation in many countries. Until now, most of the work has been on plant regeneration by adventitious organogenesis from callus which may result in phenotypic variation in plants. Only a few reports are available using explants from mature vines, which is desirable to maintain uniformity and genetic purity. Hardening and acclimatization of this fruit requires more attention as hairless thin roots produced in vitro die shortly after transplanting to soil. This makes the establishment of small plants a difficult proposition. From the literature cited, it is evident that kiwifruit is highly amenable for in vitro studies as various explants have been favourably found to resp...
Journal Article•
TL;DR: An efficient plant regeneration system was developed for two important Indian chickpea cultivars, C-235 and HC-1, and regenerated shoots had normal morphology and were successfully rooted in half strength MS medium under partial dark conditions.
Abstract: An efficient plant regeneration system was developed for two important Indian chickpea cultivars, C-235 and HC-1. Immature cotyledons (7-8 mm) directly formed shoots without an intervening callus phase on MS medium containing B 5 vitamins, BAP (2.0 mg/l), IBA (0.125 mg/l), AgNO 3 (1.69 mg/l) and phytagel (2.5 g/l). The regenerated shoots had normal morphology and were successfully rooted in half strength MS medium under partial dark conditions. Regenerated plants were transferred to potted soil. However, the survival rate of pot house transferred plants was 17.6 per cent.