Surface properties of sendai virus envelope

Surface properties of Sendai virus envelope membrane have been measured, using both biological and biophysical techniques. Both normal and trypsin-treated virus were studied. SDS gel electrophoresis showed cleavage of the F protein exclusively by trypsin. The major activity change was observed in the hemolysing activity which is an expression of F protein. Hemolysis was reduced to less than 10% of its value for intact virus. ³¹P nuclear magnetic resonance studies of the envelope surface of the native virus showed a highly restricted phospholipid headgroup environment. Interestingly, this restriction was relieved by treatment with trypsin. Thus these data suggest a role of the F protein of Sendai virus in tightly organizing the surface of the viral envelope membrane.     

Conformational analysis of pGlu-His-Amph and pGlu-His-Pro-Amph related to their central nervous system activity

The compounds pGlu-His-Pro-Amph and pGlu-His-Amph obtained from the condensation of TRH or a fragment of TRH with amphetamine show activities which are different regarding the parent compounds. Although the two derivatives exhibit about the same low toxicity they differ in several pharmacological properties. Physicochemical analysis by 1H-NMR and CD spectroscopy was carried out in order to detect in the two compounds conformational differences that might explain their different activities. The results show that in the proline containing peptide the amphetamine has a hindered rotation in comparison with the compounds devoid of proline. This, together with the occurrence of a cis conformer having different properties than the trans conformer could be the origin of the biological difference observed between the two hybrid compounds.     

Survivin withdrawal by nuclear export failure as a physiological switch to commit cells to apoptosis

Apoptosis is a tightly controlled process regulated by many signaling pathways; however, the mechanisms and cellular events that decide whether a cell lives or dies remain poorly understood. Here we showed that when a cell is under apoptotic stress, the prosurvival protein Survivin redistributes from the cytoplasm to the nucleus, thus acting as a physiological switch to commit the cell to apoptosis. The nuclear relocalization of Survivin is a result of inefficient assembly of functional RanGTP–CRM1–Survivin export complex due to apoptotic RanGTP gradient collapse. Subsequently, Survivin undergoes ubiquitination, which not only physically prevents its diffusion back to the cytoplasm but also facilitates its degradation. Together, this spatial and functional regulation of Survivin abolishes its cytoprotective effect toward the apoptotic executors and thus commits a cell to apoptosis. Our data indicate that the withdrawal of Survivin is a novel and active physiological regulatory mechanism that tilts the survival balance and promotes the progression of apoptosis.     

Sulfenylation of ENOLASE2 facilitates H2O2-conferred freezing tolerance in Arabidopsis

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Retinoic Acid Improves a Hybridoma Culture in a Fructose-Based Medium by Up-Regulation of Fructose Incorporation via Retinoid Nuclear Receptors

Fructose was focused on as an alternative sugar source to glucose in a hybridoma culture medium because it decreases lactate production during cultivation, leading to cell and product stability. But, not all human hybridoma cell lines grew well in a fructose-based serum-free medium. We found that the addition of all-trans-retinoic acid to the fructose-based medium improved the growth and monoclonal antibody production of hybridoma cell lines by up-regulation of fructose incorporation that represented increased expression of the fructose transporter, GLUT5. Selective activation of retinoid nuclear receptor by synthetic ligands showed that both retinoic acid receptors and retinoid X receptors might be related to the improvement of the fructose-based hybridoma culture. This study might be applicable to cell cultures susceptible to lactate and pH changes as well as hybridoma cultures.     

Isolation and Identification of the Female Sex Pheromone of the Potato Tuberworm Moth,Phthorimaea operculella (Zeller)

The sex pheromone produced by adult females of the potato tuberworm moth was isolated from unmated female moths reared in the laboratory. The gas Chromatographic and mass spectrometric data suggested the pheromone to be a tridecatrienyl acetate. The isolated pheromone was subjected to partial hydrogenation with hydrazine and hydrogen peroxide and subsequent ozonolysis to produce a mixture of ω-acetoxy-alkanals. They were identified by mass Chromatographic technique as 4-acetoxy-butanal, 7-acetoxy-heptanal, and 10-acetoxy-decanal respectively. Consequently, the pheromone was identified as 4,7,10-tridecatrienyl acetate except the geometric configuration.     

Critical role of helix 12 of the vitamin D(3) receptor for the partial agonism of carboxylic ester antagonists.

The carboxy-terminal alpha-helix of a nuclear receptor ligand-binding domain (LBD), helix 12, contains a critical, ligand-modulated interface for the interaction with coactivator proteins. In this study, using the example of the vitamin D receptor (VDR) and the partial antagonist ZK159222, the role of helix 12 (residues 417-427) for both antagonistic and agonistic receptor actions was investigated. Amino acid residue G423 was demonstrated to be critical for partial agonism of ZK159222, but not for the activity of the natural VDR agonist, 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)). The amount of partial agonism of ZK159222 increased when helix 12 was truncated by the last four amino acid residues (Delta424-27) and augmented even more, when in addition helix 12 of VDR's dimerization partner, retinoid X receptor (RXR), was truncated. In contrast, the low agonism of a structural derivative of ZK159222, ZK168281, was not affected comparably, whereas other close structural relatives of ZK159222 even demonstrated the same agonistic activity as that of 1alpha,25(OH)(2)D(3). The amount of agonism of ZK159222 and ZK168281 at different variations of helix 12 correlated well with VDR's ability to complex with coactivator proteins and inversely correlated with the strength of the compound's antagonistic action on 1alpha,25(OH)(2)D(3) signalling. Molecular dynamics simulations of the LBD complexed with the two antagonists could explain their different action by demonstrating a more drastic displacement of helix 12 through ZK168281 than through ZK159222. Moreover, the modelling could indicate a kink of helix 12 at amino acid residue G423, which provides the last four amino acid residues of helix 12 with a modulatory role for the partial agonism of some VDR antagonists, such as ZK159222. In conclusion, partial agonism of a VDR antagonist is lower the more it disturbs helix 12 in taking the optimal position for coactivator interaction.     

Molecular data reveal convergence in fruit characters used in the classification of Thlaspi s. I. (Brassicaceae)

Phylogenetic relationships of 18 Thlaspi s.l. species were inferred from nuclear ribosomal internal transcribed spacer (ITS) sequence data. These species represent all sections of the basic classification system of Schulz primarily based on fruit characters. The molecular phylogeny supported six clades that are largely congruent with species groups recognized by Meyer on the basis of differences in seed coat anatomy, i.e. Thlaspi s. s., Thlaspkeras, Moccaea {Raparia included), Microthhspi, Vania and Neurotropy. Some of these lineages include species which are morphologically diverse in fruit shape (e.g. Thlaspi s. s.: T. arvense - fruits broadly winged, T. ceratocarpum - fruits with prominent horns at apex, T. alliaceum - fruits very narrowly winged). Furthermore, the same fruit shape type is distributed among different clades. For instance, fruits with prominent horns at apex are found in Thlaspi s. s. ( T. ceratocarpum) and Thlaspiceras (T oxyceras). These results clearly indicate convergence in fruit characters previously used for sectional classification in Thlaspi s. l.