scispace - formally typeset
Search or ask a question

Showing papers by "Department of Biotechnology published in 2000"


Journal ArticleDOI
TL;DR: In batch fermentations using cocultures maximum ethanol production occurred in 48 h of fermentation at 30°C using 60 g/l starch, and Fermentation efficiency was found lower in a two-step process using α-amylase and glucoamylases-treated starch.

112 citations


Journal ArticleDOI
TL;DR: The improved anther culture procedure reported here, resulted in several fold increase in the recovery of green plants from recalcitrant indica × Basmati rice hybrids compared to previous published procedures and may accelerate the introgression of desirable genes from indica into BasMati rice using antherculture as a breeding tool.
Abstract: Fertile, green, di-haploid plants were obtained at high frequencies from several indica × Basmati rice F1 hybrids and/or F2 plant populations using an improved anther culture procedure. Anthers from cold-pretreated (10 °C for 10 d) panicles of six indica (HKR120, HKR86-3, HKR86-217, PR106, Gobind andCH2 double dwarf) and two Basmati rice (Basmati 370,Taraori Basmati) varieties and 14 heterotic indica ×Basmati F1/F2 hybrids were cultured in modified agarose-solidified N6M, Heh5M and RZM media. Best callus induction frequencies (2.6–78%) were obtained in RZM medium containing 4% (w/v) maltose,2,4-D, NAA and kinetin. F2 plants compared to F1 hybrids and parental rice varieties, were more responsive to anther culture. Androgenesis frequencies of 31–78% were obtained for indica × Basmati F2 plants in RZM medium in just 30 d which are comparable to or higher than that reported for japonica rice varieties and hybrids involving japonica rice parent(s). Agarose (1.0% w/v)-solidified MS medium containing 3.0% maltose, kinetin, BAP, and NAA, induced green shoot regeneration in 0–51% of the anther-derived callide pending upon the genotype. High plant regeneration frequencies (67–337 green plants per 1000 anthers)were obtained from anther calli of several F1hybrids (Gobind × Basmati 370 and HKR120 ×Taraori Basmati) and F2 plants (Gobind × Basmati370, Gobind × Taraori Basmati, HKR86-3 × TaraoriBasmati). A sample of 498 plants obtained from the above hybrids, were transferred to pots with>90% survival; 8–78% of these plants had >5%spikelet fertility and were diploid. In addition,18% of the haploid plants could be diploidized by submerging in 0.1% colchicine solution for 16–18 h. The improved anther culture procedure reported here, resulted in several fold increase in the recovery of green plants from recalcitrant indica × Basmati rice hybrids compared to previous published procedures. The study may accelerate the introgression of desirable genes from indica into Basmati rice using anther culture as a breeding tool.

64 citations


Journal Article
TL;DR: Using liquid medium in initial cultures reduced phenol exudation to a greater extent and gave maximum sprouting percentage when transferred to solid MS medium and inclusion of PG in rooting medium was not beneficial but shoot cultures grown in its presence gave higher rooting percentage.
Abstract: Successful in vitro propagation of clonal apple rootstock MM106 was achieved by culturing axillary buds on MS basal medium with BAP (1 mg/L), GA3 (0.5 mg/L) and IBA (0.1 mg/L). Use of liquid medium (LM) in initial cultures reduced phenol exudation to a greater extent and gave maximum sprouting percentage when transferred to solid MS medium. Phloroglucinol (PG) did not enhance sprouting of buds but increased the rate of multiplication when added in the medium. Maximum number of shoots were obtained when MS medium was supplemented with BAP (0.5 mg/L), GA3 (1 mg/L), IBA (0.1 mg/L) and PG (100 mg/L). For rooting, in vitro regenerated shoots were placed in IBA (30 mg/L) for 3 hr and transferred to solidified auxin free medium. Rooting was recorded in about 80% of shoots. Inclusion of PG in rooting medium was not beneficial but shoot cultures grown in its presence gave higher rooting percentage. Rooted plantlets showed about 70% survival rate in potting mixture of sand:soil:perlite (1:1:1).

28 citations


Journal ArticleDOI
TL;DR: Western immunoblots and immunofluorescence microscopy provided the first evidence that overexpression of Pgp-like protein occurs in arsenite-resistant Leishmania that are cross-resistant to structurally and functionally unrelated drugs and verapamil regulates drug sensitivity possibly by down-regulating Pgp expression in the arsenITE-resistantLeishmania.

26 citations


Journal ArticleDOI
TL;DR: During conversion into axenic amastigotes the changes in the expression levels of α-tubulin varied widely between the two strains, with the resistant strain being two-fold more sensitive than the wild type strain.
Abstract: Tubulin expression is known to alter due to drug resistance. Differentiation of Leishmania promastigotes into infectious amastigotes has been reported to be accompanied by differential tubulin gene expression. In this study, α-tubulin expression under various stages of differentiation was measured in an in vitro generated arsenite-resistant L. donovani strain. While levels of expression of α-tubulin were similar in wild type and resistant promastigotes, during conversion into axenic amastigotes the changes in the expression levels of α-tubulin varied widely between the two strains. Sensitivity of the two strains to paclitaxel (known to promote tubulin assembly) differed, with the resistant strain being two-fold more sensitive than the wild type strain. Paclitaxel was also seen to cause differential effects on α-tubulin levels in the two strains.

23 citations


Journal ArticleDOI
TL;DR: A novel sucrose lipid produced by Serratia marcescens MTCC 86 when grown on sucrose exhibited excellent emulsification activity with a wide variety of hydrocarbons and showed a strong ability to remove oil from the walls of the containers, indicating its potential use in cleaning operations.
Abstract: Serratia marcescens MTCC 86 when grown on sucrose produced a novel sucrose lipid that was different from the amino lipid produced from n-alkane by other strains of S. marcescens. The sucrose lipid isolated by acetone precipitation technique was found to be predominantly a mixture of 3-(3′-hydroxytetradecanoyloxy) decanoate and 3-(3′-hydroxyhexadecenoyloxy) decanoate. This sucrose lipid exhibited excellent emulsification activity with a wide variety of hydrocarbons. It was effective in recovering up to 90% residual oil from the oilsaturated sandpack column suggesting its use in enhanced oil recovery. It also showed a strong ability to remove oil from the walls of the containers, indicating its potential use in cleaning operations.

21 citations


Journal ArticleDOI
TL;DR: An arsenite-resistant strain of Leishmania donovani was generated in vitro by sequential exposure to higher concentrations of sodium m-arsenite and the membrane-associated P-type adenosine triphosphatase (ATPase) activity detected was 3-fold that found in the wild-type parasites.
Abstract: An arsenite-resistant strain of Leishmania donovani was generated in vitro by sequential exposure to higher concentrations of sodium m-arsenite. The resistant strain displayed a low level of cross-resistance to structurally unrelated drugs such as doxorubicin and pentamidine. This cross-resistance was sensitive to the calcium-channel blocker verapamil. The membrane-associated P-type adenosine triphosphatase (ATPase) activity detected in crude membrane fractions of the resistant strain was 3-fold that found in the wild-type parasites. The enhanced ATPase activity was unaffected by the presence of verapamil in the reaction mixture. However, when cells were grown in the presence of verapamil the membrane-associated ATPase activity of the resistant strain showed significant inhibition.

20 citations


Journal ArticleDOI
TL;DR: Investigations into the reason for the observed slower migration revealed that phosphorylation of tubulin on both serine and tyrosine residues was enhanced in the resistant strain when compared to the wild type strain.
Abstract: An arsenite-resistant strain of Leishmania donovani was generated in vitro by the sequential exposure of a wild type strain to increasing concentrations of sodium m-arsenite. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of whole cell lysates of the two strains revealed that a protein band at the 55 kDa position showed slower migration in the resistant samples. This band was identified as tubulin by immunoblotting, with both α- and β-tubulin showing retarded migration in the resistant strain. Investigations into the reason for the observed slower migration revealed that phosphorylation of tubulin on both serine and tyrosine residues was enhanced in the resistant strain when compared to the wild type strain.

20 citations


Journal Article
TL;DR: The application and future prospects of transformation technology to engineer the resistance against insect pests, fungal diseases, bacterial diseases, and improved nutritional quality in Basmati rice, have been addressed.
Abstract: Transgenic approach offers an attractive alternative to conventional techniques for the genetic improvement of Basmati rice because they enable the introduction of one or more genes into a leading cultivar without affecting its genetic background. During the last ten years, a rapid progress has been made towards the development of transformation methods in rice. Several transformation methods including Agrobacterium, biolistic, and DNA uptake by protoplasts, have been employed to produce transgenic rice. An array of useful genes is now available and many of these have already been transferred in rice to improve the resistance against biotic and abiotic stresses. In Basmati rice, a beginning has already been made regarding the development of tissue culture protocols, transformation methods and production of useful transgenic plants. The application and future prospects of transformation technology to engineer the resistance against insect pests (stem borer, leaf folder, brown plant hopper, gall midge), fungal diseases (blast, bakanae/foot, rot), bacterial diseases (bacterial leaf blight, sheath blight), abiotic stresses (salinity and drought) and improved nutritional quality (accumulation of provitamin A and essential amino acids in endosperm) in Basmati rice, have been addressed.

17 citations


Journal ArticleDOI
TL;DR: Use of RZM liquid and MSR1 media, respectively for anther culture and plant regeneration resulted in several fold increase in the recovery of green plants from recalcitrant indica × Basmati rice F1 hybrids/F2 plants which were comparable to those reported for japonica rice varieties/hybrids leading to the improved feasibility of using doubled haploids in genetic, breeding and mapping research with indica rice.
Abstract: An improved procedure has been developed for high frequency androgenesis in indica × Basmati rice hybrids using a liquid culture medium. Anthers from fourteen genotypes comprising of indica × Basmati rice F1 hybrids, F2 plants and the parental rice cultivars, were floated in liquid RZM, N6M, and Heh5M media. Anther culture frequencies (percentage of anthers forming calluses) in most of the genotypes were significantly higher in RZM medium (16–75%) compared to those obtained in N6M (7–29%) and Heh5M (7–41%) media. Agarose (1.0% w/v)-solidified MSR1 medium containing 3.0% (w/v) maltose, 1 mg l−1 kinetin, 1 mg l−1 6-benzyladenine (BA) and 0.5 mg l−1α-naphthalene acetic acid (NAA) induced green shoot regeneration at high frequencies compared to the medium (MSR2) lacking BA. In all the genotypes, microspore calluses initiated in RZM medium regenerated green shoots with over tenfold higher frequencies compared to the calluses initiated in other two media. High plant regeneration frequencies (up to 270 green plants/1000 anthers) were obtained from microspore-derived calluses of some of the F1 hybrids (Gobind × Basmati 370, Gobind × Taraori Basmati) and F2 plants (Gobind × Basmati 370, Gobind × Taraori Basmati, HKR86-3 × Taraori Basmati) as compared to their actual parents. Cytological analysis of the root tips of the progeny seedlings of the microspore-derived plants revealed haploids at a frequency of about 50%; 22% of the microspore- derived plants had > 5% spikelet fertility and were diploid. Use of RZM liquid and MSR1 media, respectively for anther culture and plant regeneration resulted in several fold increase in the recovery of green plants from recalcitrant indica × Basmati rice F1 hybrids/F2 plants which were comparable to those reported for japonica rice varieties/hybrids leading to the improved feasibility of using doubled haploids in genetic, breeding and mapping research with indica rice.

16 citations


Journal ArticleDOI
TL;DR: Results suggest that morphine via opioid receptors, in a concentration-dependent biphasic manner, modulated the P.b.SA-induced de novo production of CSFs by macrophages, in vitro.

Journal ArticleDOI
TL;DR: The immune responses in man to this 36-kDa amoebic molecule indicate a potential specific role for this molecule in invasive amoEBiasis.
Abstract: A 36-kDa antigen of axenically grown pathogenic Entamoeba histolytica (HM1-IMSS) was eluted from the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)-resolved crude amoebic extract antigens. The immunoreactivity of this partially purified 36-kDa antigen with monoclonal antibody (MoAb) 3D10 altered significantly (P 0.5), thereby indicating the protein nature of the epitope recognized by MoAb 3D10. The epitope was found to be localized on the surface as well as in the cytoplasm of the E. histolytica trophozoites with the majority of it in the cytoplasm. In addition, this epitope was also found to be present on the cyst form of the parasite. The 36-kDa molecule was recognized by the sera from 29 (85%) of the 34 patients with amoebic liver abscess and five (83%) of the six patients with amoebic colitis. No serum samples from asymptomatic cyst passers, from patients with non-amoebic hepatic or intestinal disorders and apparently healthy subjects had antibodies that reacted with this 36-kDa molecule. The immune responses in man to this 36-kDa amoebic molecule indicate a potential specific role for this molecule in invasive amoebiasis.