Showing papers by "Department of Biotechnology published in 1996"

Embryo rescue in plants -- a review

Abstract: The plant breeders usually rescue inherently weak, immature or hybrid embryos to prevent degeneration. The successful production of plants from the cultured embryos largely depends upon the maturation stage and the composition of the medium. Abortion of embryos at one or the other stage of development is a characteristic feature of distant hybridization. For the first time successful embryo culture to obtain an interspecific cross between Linum perenne × L. austriacum was demonstrated by Laibach (1925, 1929). Since then several refinements have been made in embryo culture/embryo rescue techniques which have been a popular approach for raising hybrids from a number of incompatible crosses. Currently embryo rescue holds great promise not only for effecting wide crosses, but also for obtaining plants from inherently weak embryos, obtaining haploid plants as well as for shortening the breeding cycle.

Role of hydrodynamic shear in the cultivation of animal, plant and microbial cells

Abstract: The rapid developments in biotechnology have resulted in the identification and use of a large variety of biologically active substances produced from microbial, plant and animal origin. These range from enzymes and antibiotics to highly complex molecules such as immunoglobulins, growth factors and hormones. The advances in bioprocess technology have enabled the cultivation of different micro-organisms, namely bacteria, yeast and fungi, on a large scale. The potential use of plant and animal cells has, however, not yet been completely realized. One of the major limitations in the scale-up of plant and animal cell culture is the shear sensitivity of these cells. This arises owing to the large size of the cells. In addition, animal cells are especially fragile because of the lack of cell walls.

Kinetics of biosurfactant production by Pseudomonas aeruginosa strain BS2 from industrial wastes

Abstract: Batch kinetic studies were carried out on rhamnolipid biosurfactant production from synthetic medium, industrial wastes viz. distillery and whey waste as substrates. The results indicated that the specific growth rates (μ max) and specific product formation rates (V max) from both the wastes are comparatively better than the synthetic medium, revealing that both the industrial wastes (distillery and whey) can be successfully utilized as substrates for biosurfactant production.

Transgenic grain legumes obtained by in planta electroporation-mediated gene transfer.

Abstract: Electroporation-mediated gene transfer into intact plant tissues was demonstrated in pea, cowpea, lentil, and soybean plants. Transient expression of a chimericgus reporter gene was used to monitor the uptake and expression of the introduced DNA in electroporated nodal axillary buds in vivo. The branches that grew out of the nodal meristems were chimeric and expressed the introduced gene up to 20 d after electroporation. Transgenic R1 pea, lentil, and cowpea plants were recovered from seeds originating on these chimeric branches as shown by Southern blot hybridization and GUS expression. Transgenic R2 soybean and lentil plants were also obtained. Segregation ratios in these populations showed a strong bias against transgene presence or expression.

Engineering antibiotic producers to overcome the limitations of classical strain improvement programs.

Abstract: Improvement of the antibiotic yield of industrial strains is invariably the main target of industry-oriented research. The approaches used in the past were rational selection, extensive mutagenesis, and biochemical screening. These approaches have their limitations, which are likely to be overcome by the judicious application of recombinant DNA techniques. Efficient cloning vectors and transformation systems have now become available even for antibiotic producers that were previously difficult to manipulate genetically. The genes responsible for antibiotic biosynthesis can now be easily isolated and manipulated. In the first half of this review article, the limitations of classical strain improvement programs and the development of recombinant DNA techniques for cloning and analyzing genes responsible for antibiotic biosynthesis are discussed. The second half of this article addresses some of the major achievements, including the development of genetically engineered microbes, especially with reference to beta-lactams, anthracyclines, and rifamycins.

Micropropagation of Wrightia tomentosa (Roxb.) Roem et Schult

Abstract: A complete protocol for micropropagation of Wrightia tomentosa is described. Multiple shoots were induced in vitro from cotyledonary node segments through forced axillary branching. Ninety eight per cent of the nodal segments produced an average of eight shoots per node within three weeks on agar-solidified Murashige and Skoog's medium (1962) supplemented with 5.0 mgl-' BAP. After establishment of cultures and initiation of shoot buds, a cluster of shoots with the mother explant were subsequently transferred to medium containing a lower (1.0 mgl- ') concentration of BAP to achieve a three-fold rate of multiplication during every subculture of three weeks. Nodal segments from in vitro raised shoots were also used to initiate new culture cycle. The shoots could be multiplied for 36 months without loss of vigour. Eighty per cent of the shoots were successfully rooted when their lower ends were dipped in pre-autoclaved IBA solution (500 mgl- ' for 5 min) followed by their implantation on modified MS medium (m...