Morphological and cytological studies of colchicine-induced tetraploids inTorenia fournieri lind

The present paper concerns a morphological and cytological comparison between the naturally occurring diploid and the colchicine induced tetraploid ofTorenia fournieri Lind.Treatment of growing points of young seedlings with 0.20% aqueous colchicine for 10 hours on two successive days was most effective in inducing tetraploidy. The induced tetraploids showed the usual gigas characters associated with autotetraploidy. There was a significant reduction in pollen fertility and seed setting of tetraploids as compared to their diploid progenitors.The chromosome numbers of the diploids and the induced tetraploids were determined as n=9 and n=18, respectively. The diploids showed normal meiosis whereas tetraploids were characterized by a high frequency of unequal distribution of chromosomes at anaphase. The induced tetraploids possessed larger flowers. The variability in flower size of the tetraploids offers a good scope for evolving a better horticultural variety of this species.     

Retinyl esters form lipid droplets independently of triacylglycerol and seipin

Lipid droplets store neutral lipids, primarily triacylglycerol and steryl esters. Seipin plays a role in lipid droplet biogenesis and is thought to determine the site of lipid droplet biogenesis and the size of newly formed lipid droplets. Here we show a seipin-independent pathway of lipid droplet biogenesis. In silico and in vitro experiments reveal that retinyl esters have the intrinsic propensity to sequester and nucleate in lipid bilayers. Production of retinyl esters in mammalian and yeast cells that do not normally produce retinyl esters causes the formation of lipid droplets, even in a yeast strain that produces only retinyl esters and no other neutral lipids. Seipin does not determine the size or biogenesis site of lipid droplets composed of only retinyl esters or steryl esters. These findings indicate that the role of seipin in lipid droplet biogenesis depends on the type of neutral lipid stored in forming droplets.     

Interactions between EB1 and Microtubules: DRAMATIC EFFECT OF AFFINITY TAGS AND EVIDENCE FOR COOPERATIVE BEHAVIOR*

Plus end tracking proteins (+TIPs) are a unique group of microtubule binding proteins that dynamically track microtubule (MT) plus ends. EB1 is a highly conserved +TIP with a fundamental role in MT dynamics, but it remains poorly understood in part because reported EB1 activities have differed considerably. One reason for this inconsistency could be the variable presence of affinity tags used for EB1 purification. To address this question and establish the activity of native EB1, we have measured the MT binding and tubulin polymerization activities of untagged EB1 and EB1 fragments and compared them with those of His-tagged EB1 proteins. We found that N-terminal His tags directly influence the interaction between EB1 and MTs, significantly increasing both affinity and activity, and that small amounts of His-tagged proteins act synergistically with larger amounts of untagged proteins. Moreover, the binding ratio between EB1 and tubulin can exceed 1:1, and EB1-MT binding curves do not fit simple binding models. These observations demonstrate that EB1 binding is not limited to the MT seam, and they suggest that EB1 binds cooperatively to MTs. Finally, we found that removal of tubulin C-terminal tails significantly reduces EB1 binding, indicating that EB1-tubulin interactions are mediated in part by the same tubulin acidic tails utilized by other MAPs. These binding relationships are important for helping to elucidate the complex of proteins at the MT tip.     

Efficient regeneration of plantlets from callus and mesophyll derived protoplasts of <Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> L.

A protocol for plant regeneration from mesophyll and callus protoplasts of Robinia pseudoacacia L. was developed. For leaves from in vitro raised shoots, an enzyme combination of 2.0% cellulose and 0.3% macerozyme for a digestion period of 20 h resulted in the best yield of protoplasts (9.45 × 10⁵ protoplast/g fresh weight). Mesophyll-derived protoplasts started cell wall regeneration within 24 h of being embedded in Nagata and Takebe (NT) medium supplemented with 5 μM NAA and 1 μM BAP followed by the first cell division on day three of culture and micro-colony (32 cells) formation within day 7–10 in the same medium. However, using callus as the starting material, a combination of 2.0% cellulose and 1.0% macerozyme for a digestion period of 24 h gave the highest protoplast yield (3.2 × 10⁵ protoplast/g fresh weight). Cell wall regeneration in callus-derived protoplasts started within 24 h followed by the first cell division on the day three (96 h) and the appearance of microcolonies of more than 32 cells by the end of first week (144 h) of culture on solid WPM medium supplemented with 5 μM NAA and 1 μM BAP. Microcalli were visible to the naked eye after 45 days on solid WPM medium. Proliferation of macro-calli was successfully accomplished on solid Murashige and Skoog (MS) medium with 5 μM NAA and 5 μM BAP. Both mesophyll and callus protoplast-derived calli produced shoots on MS medium with 0.5 μM NAA and 1 μM BAP within 25–30 days and multiplied on MS medium with 1.25 μM BAP. Excised microshoots were dipped in 1–2 ml of 2.0 μM IBA for 24 h under dark aseptic conditions and transferred to double sterilized sand for rooting. The flasks containing sand were inoculated with Rhizobium for in vitro nodulation. Forty-five plants transferred to pots in the glasshouse established well.     

Tumor necrosis factor-α-mediated severity of idiopathic retinal periphlebitis in young adults (Eales’ disease): implication for anti-TNF-α therapy

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic inflammatory cytokine. Tumor necrosis factor-alpha was evaluated in the serum samples of patients with idiopathic retinal periphlebitis in young adults (Eales’ disease). Retinal periphlebitis was graded according to a new grading system based on severity of inflammation (grade 1–4). Quantification of the TNF-α levels was carried out using ELISA kit in the serum samples of young adults with idiopathic retinal periphlebitis (n = 17) and healthy controls (n = 17) of similar age. Tumor necrosis factor-α level was found to be significantly raised in cases with retinal periphlebitis as compared with controls (p < 0.001). Higher levels of TNF-α were found to be associated with increased severity of retinal periphlebitis. Tumor necrosis factor-α represents a novel target for controlling inflammatory activity in idiopathic retinal periphlebitis. Higher levels of TNF-α, in association with the increased severity of retinal periphlebitis, have implications for early anti-TNF-α therapy.     

Natural products drug discovery research in India: status and appraisal

Discovery of a new drug is time consuming and laborious process. Natural products have long been a thriving source for the discovery of new drugs due to their chemical diversity and ability to act on various biological targets. The phytochemical exploration of indigeneous flora has contributed to some extent in this race for the discovery of new drugs. The traditional Indian systems of medicine has been a part of our lifestyle since ages and the classical texts like Ayurveda and Charak Samhita have served as materia medica for this purpose. This review focuses on the contributions made from India in the drug discovery and development process and provides future directions in the area.     

Biomimetic synthesis, antimicrobial, antileishmanial and antimalarial activities of euglobals and their analogues

In the present communication, naturally occurring phloroglucinol-monoterpene adducts, euglobals G1-G4 (3b/a and 4a/b) and 16 new analogues (13a/b-18a/b and 19-22) were synthesized by biomimetic approach. These synthetic compounds differ from natural euglobals in the nature of monoterpene and acyl functionality. All of these compounds were evaluated for their antibacterial, antifungal, antileishmanial and antimalarial activities. Analogue 17b possessed good antibacterial activity against methicillin-resistant Staphylococcus aureus, while analogues 19-22 possessed potent antifungal activity against Candida glabrata with IC50s ranging from 1.5 to 2.5 microg/mL. Euglobals along with all synthesized analogues exhibited antileishmanial activity. Amongst these, euglobal G2 (3a), G3 (4a) and analogues 13a and 14a showed potent antileishmanial activity with IC50s ranging from 2.8 to 3.9 microg/mL. Analogue 16a possessed antimalarial activity against chloroquine sensitive D6 clone of Plasmodium falciparum. None of the compounds showed toxicity against mammalian kidney fibroblasts (vero cells) upto the concentration of 4.76 microg/ml.     

Quantum dots laser desorption/ionization MS: multifunctional CdSe quantum dots as the matrix,concentrating probes and acceleration for microwave enzymatic digestion for peptide analysis and high resolution detection of proteins in a linear MALDI‐TOF MS

We report the first use of functionalized cadmium selinide quantum dots (CdSe QDs) with 11‐mercaptoundecanoic acid (MUA) as the matrix for the selective ionization of proteins with high resolution and rapid analysis of amino acids and peptides by using quantum dots laser desorption/ionization mass spectrometry (QDLDI‐MS). The mercaptocarboxylic groups of CdSe QDs have been known to be an effective affinity probe to interact with the biomolecules at low abundance level. Using these QDs as the matrix, sensitivity of the method was greatly enhanced and the LOQ of peptides was found to be 100 pM with RSD <10%. The QDLDI‐MS is capable for the selective ionization of insulin, lysozyme and myoglobin with high resolution, which is not observed with sinapic acid (SA) as the matrix. The QDLDI‐MS technique offers many advantages for the analysis of amino acids, peptides and proteins with regard to simplicity, rapidity, sensitivity and the mass spectra were generated in the presence of signal suppressors such as urea and Trition X‐100. In addition, the CdSe QDs have been successfully applied as preconcentrating probes for the analysis of digested peptides in lysozyme from chicken egg white by microwave‐assisted enzymatic digestion. This indicates that the QDs are able to absorb radiation from microwave and their ability to trap peptides from microwave‐digested lysozyme. These results demonstrate that the CdSe QDs are promising candidates for the selective ionization of the analytes with an accurate platform to the rapid screening of biomolecules.     

Synthesis and evaluation of β-carboline derivatives as inhibitors of human immunodeficiency virus

A series of β-carboline derivatives were synthesized by utilizing aromatization and chemoselective alkylation method recently reported from our laboratory. Synthesized derivatives were evaluated for anti-HIV activity in human CD4+ T cell line (CEM-GFP) infected with HIV-1 NL_4.3 virus. 1-Formyl-β-carboline-3-carbxylic acid methyl ester (15) showed inhibition of human immunodeficiency virus at IC₅₀ = 2.9 μM.