Synthesis and structure-activity relationships of N-{1-[(6-fluoro-2-naphthyl)methyl]piperidin-4-yl}benzamide derivatives as novel CCR3 antagonists

A novel class of potent CCR3 receptor antagonists were designed and synthesized starting from N-{1-[(6-fluoro-2-naphthyl)methyl]piperidin-4-yl}benzamide (1),which was found by subjecting our chemical library to high throughput screening (HTS). The CCR3 inhibitory activity of the synthesized compounds against eotaxin-induced Ca(2+) influx was evaluated using CCR3-expressing preB cells. Systematic chemical modifications of 1 revealed that the 6-fluoro-2-naphthylmethyl moiety was essential for CCR3 inhibitory activity in this new series of CCR3 antagonists. Further structural modifications of the benzamide and piperidine moieties of 1 led to the identification of exo-N-{8-[(6-fluoro-2-naphthyl)methyl]-8-azabicyclo[3.2.1]oct-3- yl}biphenyl-2-carboxamide [corrected] (31) as a potent CCR3 antagonist with an IC(50) value of 0.020 microM.     

Discovery of mitocryptide-1, a neutrophil-activating cryptide from healthy porcine heart

Although neutrophils are known to migrate in response to various chemokines and complement factors, the substances involved in the early stages of their transmigration and activation have been poorly characterized to date. Here we report the discovery of a peptide isolated from healthy porcine hearts that activated neutrophils. Its primary structure is H-Leu-Ser-Phe-Leu-Ile-Pro-Ala-Gly-Trp-Val-Leu-Ser-His-Leu-Asp-His-Tyr-Lys-Arg-Ser-Ser-Ala-Ala-OH, and it was indicated to originate from mitochondrial cytochrome c oxidase subunit VIII. This peptide caused chemotaxis at concentrations lower than that inducing beta-hexosaminidase release. Such responses were observed in neutrophilic/granulocytic differentiated HL-60 cells but not in undifferentiated cells, and G(i2)-type G proteins were suggested to be involved in the peptide signaling. Moreover the peptide activated human neutrophils to induce beta-hexosaminidase secretion. A number of other amphipathic neutrophil-activating peptides presumably originating from mitochondrial proteins were also found. The present results suggest that neutrophils monitor such amphipathic peptides including the identified peptide as an initiation signal for inflammation at injury sites.     

Drought induction of Arabidopsis 9-cis-epoxycarotenoid dioxygenase occurs in vascular parenchyma cells

The regulation of abscisic acid (ABA) biosynthesis is essential for plant responses to drought stress. In this study, we examined the tissue-specific localization of ABA biosynthetic enzymes in turgid and dehydrated Arabidopsis (Arabidopsis thaliana) plants using specific antibodies against 9-cis-epoxycarotenoid dioxygenase 3 (AtNCED3), AtABA2, and Arabidopsis aldehyde oxidase 3 (AAO3). Immunohistochemical analysis revealed that in turgid plants, AtABA2 and AAO3 proteins were localized in vascular parenchyma cells most abundantly at the boundary between xylem and phloem bundles, but the AtNCED3 protein was undetectable in these tissues. In water-stressed plants, AtNCED3 was detected exclusively in the vascular parenchyma cells together with AtABA2 and AAO3. In situ hybridization using the antisense probe for AtNCED3 showed that the drought-induced expression of AtNCED3 was also restricted to the vascular tissues. Expression analysis of laser-microdissected cells revealed that, among nine drought-inducible genes examined, the early induction of most genes was spatially restricted to vascular cells at 1 h and then some spread to mesophyll cells at 3 h. The spatial constraint of AtNCED3 expression in vascular tissues provides a novel insight into plant systemic response to drought stresses.     

Selectable tolerance to herbicides by mutated acetolactate synthase genes integrated into the chloroplast genome of tobacco

Strategies employed for the production of genetically modified (GM) crops are premised on (1) the avoidance of gene transfer in the field; (2) the use of genes derived from edible organisms such as plants; (3) preventing the appearance of herbicide-resistant weeds; and (4) maintaining transgenes without obstructing plant cell propagation. To this end, we developed a novel vector system for chloroplast transformation with acetolactate synthase (ALS). ALS catalyzes the first step in the biosynthesis of the branched amino acids, and its enzymatic activity is inhibited by certain classes of herbicides. We generated a series of Arabidopsis (Arabidopsis thaliana) mutated ALS (mALS) genes and introduced constructs with mALS and the aminoglycoside 3'-adenyltransferase gene (aadA) into the tobacco (Nicotiana tabacum) chloroplast genome by particle bombardment. Transplastomic plants were selected using their resistance to spectinomycin. The effects of herbicides on transplastomic mALS activity were examined by a colorimetric assay using the leaves of transplastomic plants. We found that transplastomic G121A, A122V, and P197S plants were specifically tolerant to pyrimidinylcarboxylate, imidazolinon, and sulfonylurea/pyrimidinylcarboxylate herbicides, respectively. Transplastomic plants possessing mALSs were able to grow in the presence of various herbicides, thus affirming the relationship between mALSs and the associated resistance to herbicides. Our results show that mALS genes integrated into the chloroplast genome are useful sustainable markers that function to exclude plants other than those that are GM while maintaining transplastomic crops. This investigation suggests that the resistance management of weeds in the field amid growing GM crops is possible using (1) a series of mALSs that confer specific resistance to herbicides and (2) a strategy that employs herbicide rotation.     

Isolation and characterization of the <Emphasis Type="Italic">Larix gmelinii </Emphasis><Emphasis Type="Italic">ANGUSTIFOLIA</Emphasis> (<Emphasis Type="Italic">LgAN</Emphasis>) gene

ANGUSTIFOLIA (AN), a plant homolog of C-terminal binding protein, controls the polar elongation of leaf cells and the trichome-branching pattern in Arabidopsis thaliana. In the present study, degenerate PCR was used to isolate an ortholog of AN, referred to as LgAN, from larch (Larix gmelinii). The LgAN cDNA is predicted to encode a protein of 646 amino acids that shows striking sequence similarity to AN proteins from other plants. The predicted amino acid sequence has a conserved NAD-dependent 2-hydroxy acid dehydrogenase (D2-HDH) motif and a plant AN-specific LxCxE/D motif at its N-terminus, as well as a plant-specific long C-terminal region. The LgAN gene is a single-copy gene that is expressed in all larch tissues. Expression of the LgAN cDNA rescued the leaf width and trichome-branching pattern defects in the angustifolia-1 (an-1) mutant of Arabidopsis, showing that the LgAN gene has effects complementary to those of AN. These results suggest that the LgAN gene has the same function as the AN gene.     

Cloning and sequencing of the gene for cellobiose 2-epimerase from a ruminal strain of Eubacterium cellulosolvens

Cellobiose 2-epimerase (CE; EC 5.1.3.11) is known to catalyze the reversible epimerization of cellobiose to 4-O-beta-d-glucopyranosyl-d-mannose in Ruminococcus albus cells. Here, we report a CE in a ruminal strain of Eubacterium cellulosolvens for the first time. The nucleotide sequence of the CE had an ORF of 1218 bp (405 amino acids; 46 963.3 Da). The CE from E. cellulosolvens showed 44-54% identity to N-acyl-d-glucosamine 2-epimerase-like hypothetical proteins in the genomes of Coprococcus eutactus, Faecalibacterium prausnitzii, Clostridium phytofermentans, Caldicellulosiruptor saccharolyticus, and Eubacterium siraeum. Surprisingly, it exhibited only 46% identity to a CE from R. albus. The recombinant enzyme expressed in Escherichia coli was purified by two-step chromatography. The purified enzyme had a molecular mass of 46.7 kDa and exhibited optimal activity at around 35 degrees C and pH 7.0-8.5. In addition to cello-oligosaccharides, it converted lactose to epilactose (4-O-beta-d-galactopyranosyl-d-mannose).     

Combination of Tumor Necrosis Factor Alpha and Interferon Alpha Induces Apoptotic Cell Death through a c-myc–Dependent Pathway in p53 Mutant H226br Non–Small-Cell Lung Cancer Cell Line

We investigated the role of wild-type p53 and c-myc activity in apoptosis induced by a combination of natural human tumor necrosis factor alpha (TNF-α) and natural human interferon alpha (IFN-α). Studies were performed with two human non–small-cell lung cancer cell lines, H226b, which has wild-type p53, and H226br, which has a mutant p53. The combination of IFN-α and TNF-α significantly inhibited cell growth and induced apoptotic cell death of both H226b and H226br, compared with IFN-α or TNF-α alone. Treatment with one or both cytokines did not affect the expression level of p53 in both cell lines. These results suggest that the combination of IFN-α/TNF-α induces apoptotic cell death through a p53- independent pathway. The c-myc oncogene is known to be involved in apoptosis induced by TNF. Antisense c-myc oligonucleotides have been reported to modulate cell growth or apoptosis in several cell lines. Antisense oligodeoxynucleotides were added to the culture of H226br cells before the addition of IFN-α/TNF-α. Antisense c-myc inhibited IFN-α/TNF-α cytotoxicity and apoptotic cell death. In conclusion, this study provides support for the speculation that TNF-α/IFN-α induce apoptosis through a c-myc–dependent pathway rather than a p53-dependent pathway.     

An automated prediction of MHC class I-binding peptides based on positional scanning with peptide libraries

Specificities of three mouse major histocompatibility complex (MHC) class I molecules, Kb, Db, and Ld, were analyzed by positional scanning using combinatorial peptide libraries. The result of the analysis was used to create a scoring program to predict MHC-binding peptides in proteins. The capacity of the scoring was then challenged with a number of peptides by comparing the prediction with the experimental binding. The score and the experimental binding exhibited a linear correlation but with substantial deviations of data points. Statistically, for approximately 80% of randomly chosen peptides, MHC-binding capacity could be predicted within one log concentration of peptides for a half-maximal binding. Known cytotoxic T-lymphocyte epitope peptides could be predicted, with a few exceptions. In addition, frequent findings of MHC-binding peptides with incomplete or no anchor amino acid(s) suggested a substantial bias introduced by natural antigen processing in peptide selection by MHC class I molecules.