A Novel approach for Agrobacterium-mediated germ line transformation of Indian Bread wheat (Triticum aestivum) and Pasta wheat (Triticum durum)

Recalcitrance of wheat towards tissue culture procedures has hampered the wide use of conventional transformation techniques for its improvement. In the present study, a novel, non-tissue culture, cost effective approach has been established for the introduction of transgenes in wheat. Dry, mature seeds of two Indian varieties of wheat, Triticum aestivum cv. HD2329 (bread wheat), and Triticum durum cv. PDW215 (pasta wheat), were co-cultivated with Agrobacterium strain GV2260 (p35SGUSINT) and LBA4404 (pCAMBIA 3301), respectively, in the presence of 200 μM acetosyringone. The plantlets testing gus positive were raised till maturity in garden pots. T0 lines were screened by PCR for presence of selectable markers in the transformed plants followed by confirmation with Southern hybridization. In bread wheat, nptII was detected in five primary transformed lines (T0) (ws1, ws2, ws3, ws4, ws5) and the bar gene in three putatively transformed durum wheat lines (wsb1, wsb2, wsb3). The transformation efficiency was calculated as 1.16%, and 0.84% for T. aestivum and T. durum, respectively.Â

An early auxin-responsive Aux/IAA gene from wheat (Triticum aestivum) is induced by epibrassinolide and differentially regulated by light and calcium

The plant hormone auxin plays a central role in regulating many aspects of plant growth and development. This largely occurs as a consequence of changes in gene expression. The Aux/IAA genes are best characterized among the early auxin-responsive genes, which encode short-lived transcriptional repressors. In most plants examined, including Arabidopsis, soybean, and rice, the Aux/IAA genes constitute a large gene family. By screening the available databases, at least 15 expressed sequence tags (ESTs) have been identified from wheat (Triticum aestivum), which exhibit high sequence identity with Aux/IAA homologues in other species. One of these Aux/IAA genes, TaIAA1, harbouring all the four conserved domains characteristic of the Aux/IAA proteins, has been characterized in detail. The expression of TaIAA1 is light-sensitive, tissue-specific, and is induced within 15-30 min of exogenous auxin application. Also, the TaIAA1 transcript levels increase in the presence of a divalent cation, Ca2+, and this effect is reversed by the calcium-chelating agent, EGTA. The TaIAA1 gene qualifies as the primary response gene because an increase in its transcript levels by auxin is unaffected by cycloheximide. In addition to auxin, the TaIAA1 gene is also induced by brassinosteroid, providing evidence that interplay between hormones is crucial for the regulation of plant growth and development

Membrane interactions of latarcins: Antimicrobial peptides from spider venom

A group of seven peptides from spider venom with diverse sequences constitute the latarcin family. They have been described as membrane-active antibiotics, but their lipid interactions have not yet been addressed. Using circular dichroism and solid-state 15N-NMR, we systematically characterized and compared the conformation and helix alignment of all seven peptides in their membrane-bound state. These structural results could be correlated with activity assays (antimicrobial, hemolysis, fluorescence vesicle leakage). Functional synergy was not observed amongst any of the latarcins. In the presence of lipids, all peptides fold into amphiphilic α-helices as expected, the helices being either surface-bound or tilted in the bilayer. The most tilted peptide, Ltc2a, possesses a novel kind of amphiphilic profile with a coiled-coil-like hydrophobic strip and is the most aggressive of all. It indiscriminately permeabilizes natural membranes (antimicrobial, hemolysis) as well as artificial lipid bilayers through the segregation of anionic lipids and possibly enhanced motional averaging. Ltc1, Ltc3a, Ltc4a, and Ltc5a are efficient and selective in killing bacteria but without causing significant bilayer disturbance. They act rather slowly or may even translocate towards intracellular targets, suggesting more subtle lipid interactions. Ltc6a and Ltc7, finally, do not show much antimicrobial action but can nonetheless perturb model bilayers

Membrane‐acting biomimetic peptoids against visceral leishmaniasis

Visceral leishmaniasis (VL) is among the most neglected tropical diseases in the world. Drug cell permeability is essential for killing the intracellular residing parasites responsible for VL, making cell-permeating peptides a logical choice to address VL. Unfortunately, the limited biological stability of peptides restricts their usage. Sequence-specific oligo-N-substituted glycines (‘peptoids’) are a class of peptide mimics that offers an excellent alternative to peptides in terms of ease of synthesis and good biostability. We tested peptoids against the parasite Leishmania donovani in both forms, that is, intracellular amastigotes and promastigotes. N-alkyl hydrophobic chain addition (lipidation) and bromination of oligopeptoids yielded compounds with good antileishmanial activity against both forms, showing the promise of these antiparasitic peptoids as potential drug candidates to treat VL

Assessing the Role of Ayurvedic ‘Bhasms’ as Ethno-nanomedicine in the Metal Based Nanomedicine Patent Regime

509-515The traditional medicine system is gaining wider popularity in the present times leading to increase in its commercialization at an international level. The present study is an attempt to analyse various facets of the patent regime of metal-based contemporary nanomedicine, with focus on Ayurvedic ‘Bhasms’ (alternative traditional medicine) used for various disease treatments. The study proposes a new dimension of understanding of Ayurvedic Bhasms as ethno-nanomedicine in the surging era of nanomedicine. The study proposes to have organized open-sourcing of the knowledge associated with Ayurvedic Bhasms, so that both, the ethno-nanomedicine as well as the emerging metal-based nanomedicine systems can co-exist symbiotically, thereby preventing misuse of traditional knowledge and promoting cumulative benefit to mankind

Patenting Trends in Marine Bioprospecting based Pharmaceutical Sector

122-130The ‘marine world’ boasts of innumerable life forms, each with a unique characteristic, making its genetic make-up the most sought after field for marine researchers. An array of research arenas and products ranging from cosmetics to pharmaceuticals are now harnessed from marine bioresources and patented for generating high revenues. Evolving intellectual property regime provides an insight into the current research trend of this interesting and challenging field. Patents based on six commercially important marine organisms were chosen for the patent landscape study. The present study demonstrates that pharmaceuticals is the primary field of application followed by nutraceuticals. Diseases ranging from cancer to AIDS are considered curable using these marine bioresources and seaweeds, jellyfish are common dietary constituents. The study also indicates that the number of PCT filings far exceeds the number of patents filed in regional patent offices. In the study of the International Patent Classification (IPC), A61K and A23L emerged as the major codes under which patents have been filed. Another facet of the investigation analysed the present patenting scenario in India in the field of marine bioresource based pharmaceutical sector

Regeneration via somatic embryogenesis from leaf basal segments and genetic transformation of bread and emmer wheat by particle bombardment

Direct gene transformation methods such as microprojectile bombardment have been successfully employed for obtaining transgenics in cereals in general and wheat in particular. As success of any transformation strategy depends largely upon the regeneration capability of the target explant, the present investigation employs leaf basal segments to achieve high regeneration response via somatic embryogenesis. Basal segments of 5-day-old seedlings of T. aestivum var. CPAN1676 and T. dicoccum var. DDK1001 were cultured on callusing medium for 3 weeks at 26±1°C, discontinuous light followed by a culture period of 15 days at 21±1°C in continuous light. The calli were then transferred to auxin-free medium for regeneration in discontinuous light at 26±1°C. Regeneration via somatic embryogenesis was observed within 2 weeks in T. aestivum var. CPAN1676 and T. dicoccum var. DDK1001 (68 and 82%, respectively). This embryogenic calli were employed further to obtain hygromycin resistance by particle bombardment in T. aestivum and T. dicoccum. A transformation efficiency of 8.6, 7.5 and 4.9% was obtained in T. aestivum var. CPAN1676, PBW343 and T. dicoccum DDK1001, respectively. Presence of the transgene hptII (hygromycin) in T<SUB>0</SUB> plants was confirmed by Southern hybridization

Gene expression during somatic embryogenesis - recent advances

Somatic embryogenesis is a remarkable illustration of the dictum of plant totipotency. During embryogenic induction of cells, there is differential gene expression resulting in synthesis of new mRNAs and proteins. This genetic information in turn elicits diverse cellular and physiological responses that are involved in 'switching over' of the developmental programme of the somatic cells. Various model systems have been widely investigated to understand the mechanisms of gene regulation during this developmental process, and an array of genes activated or differentially expressed during somatic embryogenesis have been isolated employing various molecular techniques. Nonetheless, the precise mechanisms controlling plant gene expression and the detailed steps by which these genes direct the plantspecific process of somatic embryogenesis remain far from being clearly understood. Thus, future trends involve characterization of development-specific genes during somatic embryogenesis to provide a deeper insight in understanding the mechanisms involved during differentiation of somatic cells and phenotypic expression of cellular totipotency in higher plants