Plant regeneration from in vitro cultures of anthers and mature seeds of rice (Oryza sativa L.) cv. Basmati-370

Pollen plants were obtained from anther-derived calli of the indica rice variety Basmati-370. Anther-response (anthers producing pollen derived calli) and plant regeneration frequency from the pollen derived calli. was very low. Donor plants which flowered at the average max/min. temperature of 34.2°/23.3°C gave a significantly higher anther-response to in vitro techniques, than did those which flowered at 29.1°/16.4°C. Somatic callus induction and subsequent plant regeneration was readily obtained from mature seed embryos. While 2,4-D or 2,4,5-T (1 or 2 mg/l) proved highly efficient for callus induction, tryptophan (50 or 100 mg/l) induced a high frequency of green plants from the calli.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - 2,4,5-T 2,4,5-trichlorophenoxyacetic acid - NAA naphthaleneacetic acid - IAA indoleacetic acid - K kinetin - BA benzyladenine - Trp tryptophan - CW coconut water     

Human sialidase inhibitors: Design,synthesis, and biological evaluation of 4-acetamido-5-acylamido-2-fluoro benzoic acids

Recent advances in the sialidase biology have clarified the role of human sialidases (NEU 1 to NEU4) in the development of various disease states such as cancer, diabetes and arteriosclerosis. Isoform selective human sialidase inhibitors could be a therapeutic tool or molecular probes for the exploration of the specific functions of human sialidases. In the present study, de novo design based virtual screening was performed to find a new class of human sialidase inhibitors using the experimental crystal structure of NEU2 isoform. A few of nitro benzene and fluoro benzoic acid were identified and a series of 4-acetamido-5-acylamido-2-fluoro benzoic acids were synthesized and, the inhibitory activity of all these compounds against all human sialidase enzymes was evaluated. All these compounds were found to have a poor inhibitory activity and only NEU2 showed more sensitivity to this series of compounds as compared to other isoforms. Molecular docking was performed to gain insight regarding the binding mode of these inhibitors and thereby provided valuable information for our study on the design of selective human sialidase inhibitors further.     

Establishment of stable NaCl-resistant rice plant lines from anther culture: distribution pattern of K+/Na+ in callus and plant cells

 Soil salinity markedly suppresses the growth of rice (Oryza sativa L.). We established rice anther culture to select for rice callus lines adapted to NaCl stress and regenerated plant progenies resistant to a NaCl stress of E.C. 16–18 mS. When exposed to NaCl, NaCl-adapted rice calli lost K⁺ and accumulated little Na⁺. Conversely, plant cells lost relatively little K⁺ and accumulated Na⁺. It is plausible that, NaCl-resistant mechanisms are different at callus and plant level. The stable NaCl-resistant lines produced have potential use in elucidating the molecular mechanisms behind NaCl resistance in rice and in rice breeding. Received: 27 February 1997 / Accepted: 4 April 1997     

Inflammation,caveolae and CD38-mediated calcium regulation in human airway smooth muscle

The pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) increases expression of CD38 (a membrane-associated bifunctional enzyme regulating cyclic ADP ribose), and enhances agonist-induced intracellular Ca^2 + ([Ca^2 +]_i) responses in human airway smooth muscle (ASM). We previously demonstrated that caveolae and their constituent protein caveolin-1 are important for ASM [Ca^2 +]_i regulation, which is further enhanced by TNFα. Whether caveolae and CD38 are functionally linked in mediating TNFα effects is unknown. In this regard, whether the related cavin proteins (cavin-1 and -3) that maintain structure and function of caveolae play a role is also not known. In the present study, we hypothesized that TNFα effects on CD38 expression and function in human ASM involve caveolae. Caveolar fractions from isolated human ASM cells expressed CD38 and its expression was upregulated by exposure to 20 ng/ml TNFα (48 h). ASM cells expressed cavin-1 and cavin-3, which were also upregulated by TNFα. Knockdown of caveolin-1, cavin-1 or cavin-3 (using siRNA) all significantly reduced CD38 expression and ADP-ribosyl cyclase activity in the presence or absence of TNFα. Furthermore, caveolin-1, cavin-1 and cavin-3 siRNAs reduced [Ca^2 +]_i responses to histamine under control conditions, and blunted the enhanced [Ca^2 +]_i responses in TNFα-exposed cells. These data demonstrate that CD38 is expressed within caveolae and its function is linked to the caveolar regulatory proteins caveolin-1, cavin-1 and -3. The link between caveolae and CD38 is further enhanced during airway inflammation demonstrating the important role of caveolae in regulation of [Ca^2 +]_i and contractility in the airway.     

Synthesis and characterization of curcumin loaded polymer/lipid based nanoparticles and evaluation of their antitumor effects on MCF-7 cells

Background

Hybrid materials are synthesized using hydrophilic polymer and lipids which ensure their long term systemic circulation through intravenous administration and enhance loading of hydrophobic drugs. The purpose of this study is to prepare, characterize and evaluate the in vitro efficacy of curcumin loaded poly-hydroxyethyl methacrylate/stearic acid nanoparticles in MCF-7.

Methods

C-PSA-NPs, prepared using the emulsification–solvent evaporation method were characterized by dynamic laser scattering, SEM, AFM, FT-IR, X-ray diffraction, and TGA. The in vitro release behavior was observed in PBS pH 7.4, the anticancer potential was analyzed by MTT assay, cell cycle and apoptosis studies were performed through flow cytometry. C-PSA-NPs drug localization and cancer cell morphological changes were analyzed in MCF-7 cell line.

Results

C-PSA-NPs exhibited the mean particle size in the range of 184 nm with no aggregation. The surface charge of the material was around − 29.3 mV. Thermal studies (TGA) and surface chemistry studies (FT-IR, XRD) showed the existence of drug curcumin in C-PSA-NPs. The MTT assay indicated higher anticancer properties and flow cytometry studies revealed that there were better apoptotic activity and maximum localization of C-PSA-NPs than curcumin.

Conclusions

Polymer lipid based drug delivery appeared as one of the advancements in drug delivery systems. Through the present study, a novel polymer lipid based nanocarrier delivery system loaded with curcumin was demonstrated as an effective and potential alternative method for tumor treatment in MCF-7 cell line.

General significance

C-PSA-NPs exhibited potent anticancer activity in MCF-7 cell line and it indicates that C-PSA-NPs are a suitable carrier for curcumin.     

Light-harvesting complex II (LHCII) and its supramolecular organization in Chlamydomonas reinhardtii

LHCII is the most abundant membrane protein on earth. It participates in the first steps of photosynthesis by harvesting sunlight and transferring excitation energy to the core complex. Here we have analyzed the LHCII complex of the green alga Chlamydomonas reinhardtii and its association with the core of Photosystem II (PSII) to form multiprotein complexes. Several PSII supercomplexes with different antenna sizes have been purified, the largest of which contains three LHCII trimers (named S, M and N) per monomeric core. A projection map at a 13 Å resolution was obtained allowing the reconstruction of the 3D structure of the supercomplex. The position and orientation of the S trimer are the same as in plants; trimer M is rotated by 45° and the additional trimer (named here as LHCII-N), which is taking the position occupied in plants by CP24, is directly associated with the core. The analysis of supercomplexes with different antenna sizes suggests that LhcbM1, LhcbM2/7 and LhcbM3 are the major components of the trimers in the PSII supercomplex, while LhcbM5 is part of the “extra” LHCII pool not directly associated with the supercomplex. It is also shown that Chlamydomonas LHCII has a slightly lower Chlorophyll a/b ratio than the complex from plants and a blue shifted absorption spectrum. Finally the data indicate that there are at least six LHCII trimers per dimeric core in the thylakoid membranes, meaning that the antenna size of PSII of C. reinhardtii is larger than that of plants.     

Profilin oligomerization and its effect on poly (l-proline) binding and phosphorylation

Profilin is a cytoskeletal protein that interacts specifically with actin, phosphoinositides and poly (l-proline). Experimental results and in silico studies revealed that profilin exists as dimer and tetramer. Profilin oligomers possess weak affinity to poly (l-proline) due to unavailability of binding sites in dimers and tetramers. Phosphorylation studies indicate that profilin dimers are not phosphorylated while teramers are preferentially phosphorylated over monomers. In silico studies revealed that PKC phosphorylation site, S137 is buried in dimer while it is accessible in tetramer.     

MsrB1 (methionine-R-sulfoxide reductase 1) knock-out mice: roles of MsrB1 in redox regulation and identification of a novel selenoprotein form

Protein oxidation has been linked to accelerated aging and is a contributing factor to many diseases. Methionine residues are particularly susceptible to oxidation, but the resulting mixture of methionine R-sulfoxide (Met-RO) and methionine S-sulfoxide (Met-SO) can be repaired by thioredoxin-dependent enzymes MsrB and MsrA, respectively. Here, we describe a knock-out mouse deficient in selenoprotein MsrB1, the main mammalian MsrB located in the cytosol and nucleus. In these mice, in addition to the deletion of 14-kDa MsrB1, a 5-kDa selenoprotein form was specifically removed. Further studies revealed that the 5-kDa protein occurred in both mouse tissues and human HEK 293 cells; was down-regulated by MsrB1 small interfering RNA, selenium deficiency, and selenocysteine tRNA mutations; and was immunoprecipitated and recognized by MsrB1 antibodies. Specific labeling with (75)Se and mass spectrometry analyses revealed that the 5-kDa selenoprotein corresponded to the C-terminal sequence of MsrB1. The MsrB1 knock-out mice lacked both 5- and 14-kDa MsrB1 forms and showed reduced MsrB activity, with the strongest effect seen in liver and kidney. In addition, MsrA activity was decreased by MsrB1 deficiency. Liver and kidney of the MsrB1 knock-out mice also showed increased levels of malondialdehyde, protein carbonyls, protein methionine sulfoxide, and oxidized glutathione as well as reduced levels of free and protein thiols, whereas these parameters were little changed in other organs examined. Overall, this study established an important contribution of MsrB1 to the redox control in mouse liver and kidney and identified a novel form of this protein.