Direct plant regeneration from cultured young leaf segments of sugarcane

Young leaf segments (1.0–1.5 cm) excised from spindle explants of three commercial sugarcane varieties viz. Co J 64, Co J 83 and Co J 86 were cultured on different media compositions based on Murashige and Skoog (1962) salts. Cultured explants exhibited swelling followed by direct shoot regeneration on media containing naphthaleneacetic acid, in all the three varieties. Highest frequency 83.12% shoot regeneration occurred on Murashige and Skoog medium supplemented with naphthaleneacetic acid (5.0 mg l⁻¹) and kinetin (0.5 mg l⁻¹) in variety Co J 83. Medium devoid of naphthaleneacetic acid and supplemented with only kinetin did not induce direct shoot regeneration in any of the varieties thus tried. Subsequently profuse rooting of shoots was observed on the same medium and complete plantlets were recovered within 6 weeks. The plantlets were hardened and transferred to soil. Tissue culture derived field-grown plants were normal and exhibited faster growth and better tillering. This developed single step method of direct plant regeneration can be used for rapid mass cloning and genetic transformation of sugarcane.     

Macrophages in SHH subgroup medulloblastoma display dynamic heterogeneity that varies with treatment modality

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Growth in Axenic Culture of Isolated Shoot Apices of Eichhornia crassipes

Apical meristem culture of Eichhornia crassipes has shown that for successful regeneration, the excised meristem dome must be associated with at least the youngest leaf primordium as part of the explant and a culture medium containing coconut milk (10 %, v/v), IAA (0.1 mg/l) and kinetin (1 mg/l) as growth supplements with 2 % sucrose as carbon source.     

5-aza deoxycytidine-induced inhibition of differentiation of spermatogonia into spermatocytes in the mouse

In order to explore the significance of DNA methylation in proliferation and differentiation of germ cells in testis, 5-aza,2′-deoxycytidine (5-azaCdR), a hypomethylating agent, was administered in vivo to neonatal mice having only spermatogonial (premeiotic) cells. End-labeling of the Mspl, Hpall, and Hhal digested DNA revealed considerable loss of methylation following the treatment. Cellular and histological preparations of the testis showed complete inhibition of differentiation into spermatocytic stage. Analysis of protein synthesis in the treated and control testis by growing the cells in ³⁵S-Methionine medium and resolving the lysate by SDS-PAGE revealed that the programme of expression of at least 5 polypeptides (35.0, 31.5, 27.0, 22.5, and 18.0 KD) was altered as a result of 5-azaCdR incorporation. It appears that DNA methylation plays a critical role in the differentiation of gonia into primary spermatocytes. © 1995 wiley-Liss, Inc.     

Slow muscle myoblasts differentiating in vitro synthesize both slow and fast myosin light chains

Whether fast and slow skeletal muscles of the embryo develop from cells of a common origin or from two separate cellular origins is not known. Recent evidence suggests that prior to innervation all muscles of the embryo are of one type, the fast type, i.e., all synthesize fast but not slow myosin light chains. Innervation has been thought to play the central role in the shift of a fast to a slow muscle. Experiments reported here demonstrate that myoblasts from slow muscle regions of the embryo when isolated in tissue culture differentiate into myotubes which synthesize both fast and slow myosin light chains, and that innervation is not required to initiate slow myosin light-chain synthesis.     

Molecular Dynamics Simulations of Ibuprofen Binding to Aβ Peptides

Using replica exchange molecular dynamics simulations and the implicit solvent model we probed binding of ibuprofen to Aβ_10-40 monomers and amyloid fibrils. We found that the concave (CV) fibril edge has significantly higher binding affinity for ibuprofen than the convex edge. Furthermore, binding of ibuprofen to Aβ monomers, as compared to fibrils, results in a smaller free energy gain. The difference in binding free energies is likely to be related to the presence of the groove on the CV fibril edge, in which ibuprofen tends to accumulate. The confinement effect of the groove promotes the formation of large low-energy ibuprofen clusters, which rarely occur on the surface of Aβ monomers. These observations led us to suggest that the ibuprofen binding mechanism for Aβ fibrils is different from that for monomers. In general, ibuprofen shows a preference to bind to those regions of Aβ monomers (amino terminal) and fibrils (the CV edge) that are also the primary aggregation interfaces. Based on our findings and on available experimental data, we propose a rationale for the ibuprofen antiaggregation effect.     

Kinetics of uranous iron and ferrous iron oxidation by thiobacillus ferrooxidans

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