Biocontrol of Postharvest Rhizopus Decay of Peaches with Pichia caribbica

A new yeast antagonist, Pichia caribbica, isolated in our laboratory from the soil collected from unsprayed orchards, was evaluated for its biocontrol capability against Rhizopus stolonifer on peaches and the possible mechanisms involved. The decay incidence and lesion diameter of Rhizopus decay of peaches treated by P. caribbica were significantly reduced compared with the control fruits, and the higher the concentration of P. caribbica, the better the efficacy of the biocontrol. Rapid colonization of the yeast in peach wounds stored at 25 °C was observed. In peaches, the activities of peroxidase (POD), catalase (CAT), and phenylalanine ammonia-lyase (PAL) were significantly induced by P. caribbica treatment compared to those of the control fruits. All these results indicated that P. caribbica has a great potential for the development of commercial formulations to control postharvest Rhizopus decay of peaches. Its modes of action were based on competition for space and nutrients with pathogens, inducement of activities of defense-related enzymes such as POD, CAT, and PAL of peaches.     

CXCR4/SDF-1 pathway is crucial for TLR9 agonist enhanced metastasis of human lung cancer cell

Accumulating data suggested that CXCR4/SDF-1 pathway may play an important role in the metastasis of tumor. We previously demonstrated that CpG ODN could enhance the metastasis of human lung cancer cell via TLR9. Here we further evaluated the possible role of CXCR4/SDF-1 pathway in the enhanced metastasis of human lung cancer 95D cells induced by CpG ODN. Our data showed down-regulation of CXCR4 expression using siRNA against CXCR4 could significantly reduce the enhanced metastasis of 95D cells induced by CpG ODN both in vitro and in vivo. These results suggested that TLR9 agonist might promote the metastasis of human lung cancer cells via CXCR4/SDF-1 pathway.     

Crystallization and preliminary X-ray structure analysis of pigeon egg-white lysozyme.

Calcium binding lysozyme from pigeon egg-white was crystallized by the hanging drop vapor diffusion technique using ammonium sulphate as a precipitant. The crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), and have unit cell dimensions of a = 34.2 A, b = 34.8 A, and c = 99.4 A. One asymmetric unit contains one molecule of the pigeon lysozyme. The crystals diffract X-rays at least to 2.0 A resolution and are suitable for high resolution structure analysis. The diffraction data up to 3.0 A resolution were collected with a diffraction image processor, DIP100, using a Fuji imaging plate as an area detector. The structure was solved by the molecular replacement technique and refined to an R factor of 0.216. Least-squares fitting of the main-chains of pigeon egg-white lysozyme with those of chicken egg-white lysozyme and baboon alpha-lactalbumin showed that the main-chain folding of pigeon lysozyme is more similar to that of chicken lysozyme than that of alpha-lactalbumin. The largest differences between the pigeon and chicken lysozymes are in the surface loop regions.     

Cytoskeletal changes correlated with the loss of neuronal polarity in axotomized lamprey central neurons

Axotomy within 500 μm of the soma (close axotomy) causes identified neurons (anterior bulbar cells or ABCs) in the lamprey hindbrain to lose their normal polarity and regenerate axons ectopically from dendritic tips, while axotomy at more distal sites (distant axotomy) results in orthotopic axonal regeneration from the axon stump. We performed immunocytochemical, electron microscopic and in situ hybridization analyses comparing ABCs subjected to close and distant axotomy to elucidate the mechanism by which neuronal polarity is lost. We show that polarity loss in ABCs is selectively and invariably preceded and accompained by the following cellular changes: (1) a loss of many dendritic microtubules and their replacement with neurofilaments, (2) a loss of immunostaining for acetylated tubulin in the soma and proximal dendrites, and (3) an increase of immunostaining for phosphorylated neurofilaments in the distal dendrites. We also show that these changes do not depend on either the upregulation or spatial redistribution of neurofilament message, and thus must involve changes in the routing of neurofilament protein within axotomized ABCs. We conclude that close axotomy causes dendrites to undergo axonlike changes in the mechanisms that govern the somatofugal transport of neurofilament protein, and suggest that these changes require the reorganization of dendritic microtubules. We also suggest that the bulbous morphology and lack of f-actin in the tips of all regenerating sprouts supports the possibility that axonal regeneration in the lamprey CNS does not involve actin-mediated "pulling" of growth cones, but depends instead on the generation of internal extrusive forces.     

Inherited human Caspase 10 mutations underlie defective lymphocyte and dendritic cell apoptosis in autoimmune lymphoproliferative syndrome type II.

Caspases are cysteine proteases that mediate programmed cell death in phylogenetically diverse multicellular organisms. We report here two kindreds with autoimmune lymphoproliferative syndrome (ALPS) type II, characterized by abnormal lymphocyte and dendritic cell homeostasis and immune regulatory defects, that harbor independent missense mutations in Caspase 10. These encode amino acid substitutions that decrease caspase activity and interfere with death receptor-induced apoptosis, particularly that stimulated by Fas ligand and TRAIL. These results provide evidence that inherited nonlethal caspase abnormalities cause pleiotropic apoptosis defects underlying autoimmunity in ALPS type II.     

Purification and properties of the Escherichia coli nucleoside transporter NupG, a paradigm for a major facilitator transporter sub-family

NupG from Escherichia coli is the archetype of a family of nucleoside transporters found in several eubacterial groups and has distant homologues in eukaryotes, including man. To facilitate investigation of its molecular mechanism, we developed methods for expressing an oligohistidine-tagged form of NupG both at high levels (>20% of the inner membrane protein) in E. coli and in Xenopus laevis oocytes. In E. coli recombinant NupG transported purine (adenosine) and pyrimidine (uridine) nucleosides with apparent K(m) values of approximately 20-30 microM and transport was energized primarily by the membrane potential component of the proton motive force. Competition experiments in E. coli and measurements of uptake in oocytes confirmed that NupG was a broad-specificity transporter of purine and pyrimidine nucleosides. Importantly, using high-level expression in E. coli and magic-angle spinning cross-polarization solid-state nuclear magnetic resonance, we have for the first time been able directly to measure the binding of the permeant ([1'-(13)C]uridine) to the protein and to assess its relative mobility within the binding site, under non-energized conditions. Purification of over-expressed NupG to near homogeneity by metal chelate affinity chromatography, with retention of transport function in reconstitution assays, was also achieved. Fourier transform infrared and circular dichroism spectroscopy provided further evidence that the purified protein retained its 3D conformation and was predominantly alpha-helical in nature, consistent with a proposed structure containing 12 transmembrane helices. These findings open the way to elucidating the molecular mechanism of transport in this key family of membrane transporters.     

Search for the tumor-related proteins of transition cell carcinoma in Taiwan by proteomic analysis

To better understand the carcinogenesis of bladder cancer in Taiwan, we utilized the proteomic approach to search for potential biomarkers of transitional cell carcinoma (TCC). Analysis by 2-DE and MS/MS indicated that seven proteins are down-regulated and three proteins up-regulated in grade III samples as compared with those of grade II. Of these deregulated proteins, fatty acid binding proteins, annexin V, heat-shock protein 27, and lactate dehydrogenase have been shown to be associated with bladder cancer. Our studies also found altered expression of a group of proteins that have not been documented previously in bladder cancer, including annexin I, 15-hydroxyprostaglandin dehydrogenase, galectin-1, lysophospholipase and mitochondrial short-chain enoyl-coenzyme A hydratase 1 precursor. These results illustrate a pattern of differential protein expression between low- and high-grade tumors and it may be utilized as the molecular fingerprinting of a subset of bladder cancers. In addition, the present study provides a valuable resource in the study of pathological mechanisms in cancers of urothelial origin. The immunohistochemical staining of grade II and III TCC samples with antiserum to annexin I protein was utilized to confirm that the annexin I protein is up-regulated in grade III TCC.     

In vitro chromosome doubling of nineZantedeschia cultivars

Tetraploid plants have been produced from nineZantedeschia cultivars usingin vitro colchicine treatment. Rapidly-multiplying shoot cultures were treated on a medium containing 0.05% colchicine for 1, 2 or 4 days to induce chromosome doubling. Following the treatment, most shoots were killed but the surviving shoots were multiplied for several subcultures. These shoots were then rootedin vitro and transferred to a greenhouse. Plants were screened 2 months later by measuring stomatal length, and 110 out of 565 plants were selected as putative tetraploids with a stomatal length significantly greater than in diploid control plants. Chromosome counts were carried out on root tips from 44 plants and confirmed that 38 were tetraploids, 2 were chimeras (predominantly tetraploid with a few octoploid cells), and 4 were diploids. Stomatal length has been rechecked in mature tetraploid plants of the cultivar Black Magic, demonstrating that stomatal length is a good indicator of ploidy level inZantedeschia. This study has shown that multiplying colchicine-treated shootsin vitro for several subcultures prior to transfer to soil produced very few chimeras. The stomatal length measurements are non-destructive and allow the rapid screening of a population for tetraploids.