New highly active taxoids from 9 beta-dihydrobaccatin-9,10-acetals

To synthesize new highly active taxoids, we designed and synthesized 9 beta-dihydro-9,10-acetal taxoids. In vitro study of these analogues clearly showed them to be more potent than docetaxel.     

Regeneration of hippocampal pyramidal neurons after ischemic brain injury by recruitment of endogenous neural progenitors

The adult brain is extremely vulnerable to various insults. The recent discovery of neural progenitors in adult mammals, however, raises the possibility of repairing damaged tissue by recruiting their latent regenerative potential. Here we show that activation of endogenous progenitors leads to massive regeneration of hippocampal pyramidal neurons after ischemic brain injury. Endogenous progenitors proliferate in response to ischemia and subsequently migrate into the hippocampus to regenerate new neurons. Intraventricular infusion of growth factors markedly augments these responses, thereby increasing the number of newborn neurons. Our studies suggest that regenerated neurons are integrated into the existing brain circuitry and contribute to ameliorating neurological deficits. These results expand the possibility of novel neuronal cell regeneration therapies for stroke and other neurological diseases.     

The crystal structure of N(1)-[2-(2-amino-ethylamino)-ethyl]-ethane-1,2-diamine (polyamines) binding to the minor groove of d(CGCGCG)(2), hexamer at room temperature

A novel experimental technique, based on atomic force microscopy (AFM), is proposed to visualize the lateral organization of membrane systems in the nanometer range. The technique involves the use of a ligand-receptor pair, biotin-avidin, which introduces a height variation on a solid-supported lipid bilayer membrane. This leads to a height amplification of the lateral membrane organization that is large enough to be clearly imaged by scanning AFM. The power of the technique is demonstrated for a binary dipalmitoylphosphocholine-diarachidoylphosphocholine lipid mixture which is shown to exhibit a distinct lateral lipid domain formation. The new and simple ligand-receptor-based AFM approach opens up new ways to investigate lipid membrane microstructure in the nanometer range as well as the lateral distribution of ligand-lipid and receptor-protein complexes in supported membrane systems.     

Coumarins and gamma-pyrone derivatives from Prangos pabularia: antibacterial activity and inhibition of cytokine release

The n-hexane and ethyl acetate extracts of the stems and the ethyl acetate extracts of roots from Prangos pabularia afforded an gamma-pyrone derivative and furanocoumarin derivatives with three glucose and gamma-pyrone (pabularin A, B and C), along with 26 previously known compounds (18 coumarins, six terpenoids and two glycosides). Their structures were established on the basis of spectroscopic studies. Of these, 16 coumarin derivatives isolated from P. pabularia were tested for antibacterial activity and inhibition of cytokine release.     

Relationship between conidial enzymes and germination of the apple blue mold,Penicillium expansum

The relationship between conidial enzymes of Penicillium expansum and spore germination was examined. The activities of xylanase and pectinase, but not of cellulase and amylase, were detected in the conidia. The levels of xylanase and pectinase were greatly enhanced by xylan and pectin as respective carbon sources in the basal medium. No conidia germinated in the basal medium without a carbon source. The type of carbon source and the enzyme levels of the conidia did not affect the rate of germination. However, a relationship was found between the enzyme levels and the elongation of the germ tubes.     

Molecular cloning, characterization, and expression analysis of the xynF3 gene from Aspergillus oryzae

The gene encoding xylanase F3 (xynF3) was isolated from a genomic library of Aspergillus oryzae KBN616, used for making shoyu koji. The structural part of xynF3 was found to be 1468 bp. The nucleotide sequence of cDNA amplified by RT-PCR showed that the open reading frame of xynF3 was interrupted by ten short introns and encoded 323 amino acids. Direct N-terminal amino acid sequencing showed that the precursor of XynF3 had a signal peptide of 22 amino acids. The predicted amino acid sequence of XynF3 has strong similarity to other family 10 xylanases from fungi. The xynF3 gene was successfully overexpressed in A. oryzae and the XynF3 was purified. The molecular mass of XynF3 estimated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 32,000. This was almost the same as the molecular mass of 32,437 calculated from the deduced amino acid sequence. The purified XynF3 showed an optimum activity at pH 5.0 and 58 degrees C. It had a Km of 6.5 mg/ml and a Vmax of 435 micromol x min(-1) x mg(-1) when birch wood xylan was used as a substrate. Expression of the xynF3 gene was analyzed using an Escherichia coli beta-glucuronidase gene as a reporter. The result indicated that xynF3 is expressed in the medium containing wheat bran as a carbon source.     

Phosphorylation of retinoblastoma-related protein by the cyclin D/cyclin-dependent kinase complex is activated at the G1/S-phase transition in tobacco

In mammals, D-type cyclin-associated kinases mainly regulate the G1/S transition by phosphorylating the retinoblastoma (Rb) protein. We previously demonstrated that in tobacco, cyclin D (Nicta; CycD3;3) is complexed with the PSTAIRE-containing cyclin-dependent kinase (CDKA) from tobacco. Here, we show that Nicta; CycD3;3-associated kinases phosphorylate both the tobacco Rb-related protein (NtRb1) and histone H1. Although NtRb1 kinase activity was detected only during the middle G1- to early S-phase, histone H1 kinase activity was observed as two peaks in G1- to S-phase and G2/M- to M-phase. Importantly, we show that the proportion of cells in the G1-phase was reduced in transgenic Bright Yellow-2 cells overexpressing Nicta; CycD3;3-GFP. Mutational analyses revealed that phosphorylation of Thr-191 in Nicta; CycD3;3 possibly is required for both full kinase activity and localization predominantly to the nucleus. These data suggest that Nicta; CycD3;3 acts as a rate-limiting regulator in the G1/S transition by forming active complexes with CDKA or its related kinases to phosphorylate Rb-related protein and potentially plays a novel role during G2/M and mitosis.