Sodium orthovanadate potentiates EGCG-induced apoptosis that is dependent on the ERK pathway

Epigallocatechin-3-gallate (EGCG) is a potent chemopreventive agent in many test systems and has been shown to inhibit tumor promotion and induce apoptosis. In the present study, we determined the effect of vanadate, a potent inhibitor of tyrosine phosphatase, on EGCG-induced apoptosis. Investigation of the mechanism of EGCG or vanadate-induced apoptosis revealed induction of caspase 3 activity and cleavage of phospholipase-gamma1 (PLC-gamma1). Furthermore, vanadate potentiated EGCG-induced apoptosis by mitogen-activated protein kinase (MAPK) signaling pathway. Treatment with EGCG plus vanadate for 24h produced morphological features of apoptosis and DNA fragmentation in U937 cells. This was associated with cytochrome c release, caspase 3 activation, and PLC-gamma1 degradation. EGCG plus vanadate activates multiple signal transduction pathways involved in coordinating cellular responses to stress. We demonstrate a requirement for extracellular signal-regulated protein kinase (ERK), a member of the mitogen-activated protein kinase family in EGCG plus vanadate-induced apoptosis in U937 cells. Elevated ERK activity that contributed to apoptosis by EGCG plus vanadate was supported by PD98059 and U0126, chemical inhibitor of MEK/ERK signaling pathway, prevented apoptosis. Taken together, our finding suggests that ERK activation plays an active role in mediating EGCG plus vanadate-induced apoptosis of U937 cells and functions upstream of caspase activation to initiate the apoptotic signal.     

Ruthenium red,inhibitor of mitochondrial Ca2+ uniporter,inhibits curcumin-induced apoptosis via the prevention of intracellular Ca2+ depletion and cytochrome c release

Curcumin, a natural, biologically active compound extracted from rhizomes of Curcuma species, has been shown to possess potent anti-inflammatory, anti-tumor, and anti-oxidative properties. The mechanism by which curcumin initiates apoptosis remains poorly understood. In the present report we investigated the effect of curcumin on the activation of the apoptotic pathway in human leukemia U937 cells. Curcumin induces apoptosis in U937 cells via a mechanism that appears to involve down-regulation of the anti-apoptotic Bcl-xL, and IAP proteins, release of cytochrome c, and activation of caspase 3. Ruthenium red, an inhibitor of mitochondrial uniporter, specifically inhibits curcumin-induced apoptosis in U937 cells. Cotreatment with ruthenium red markedly prevented the activation of caspase 3, cytochrome c release, and cell death, suggesting a role for intracellular Ca(2+) in this process. Curcumin induced a marked depletion of [Ca(2+)](i) in Caki cells bathed with both Ca(2+)-containing and -free solutions. Thapsigargin (TG), cyclopiazonic acid (CPA), and dantolene (DAN) had no effect. Ruthenium red, an inhibitor of mitochondrial uniporter, only attenuated the curcumin-induced [Ca(2+)](i) depletion in a dose-dependent manner. These data indicate that curcumin acts as a stimulator of intracellular Ca(2+) uptake into mitochondria via uniporter pathway and may involve in the execution of apoptosis.     

Pyrrolidine dithiocarbamate induces cyclooxygenase-2 expression in NIH 3T3 fibroblast cells

Pyrrolidine dithiocarbamate (PDTC) is a metal chelating compound that can exert either pro-oxidant or antioxidant effects in different situations. Several studies demonstrate that it can inhibit cyclooxygenase-2 (COX-2) expression, which may be due to its antioxidant activity. Here, we found that PDTC rather increased COX-2 expression in NIH 3T3. The increase of COX-2 expression was inhibited by adding bathocuproline disulfonic acid, a non-permeable specific copper chelator, in the incubation medium. This result suggests that PDTC exerts its effect by transporting redox-active copper ions into the cells. In support of this observation, PDTC did not induce COX-2 expression in a serum-free environment. When PDTC was added with copper in the serum-free medium, it acted as the inducer of COX-2 expression. In addition, pretreatment of N-acetyl-L-cystein or dithiothreitol, other antioxidants, inhibited the PDTC-induced COX-2 expression. Our data indicate that PDTC induces COX-2 expression in NIH 3T3 cells, which may be due to its activities as a copper chelator and a pro-oxidant.     

Complete chloroplast genome sequence of <Emphasis Type="Italic">Capsicum</Emphasis><Emphasis Type="Italic">baccatum</Emphasis> var. <Emphasis Type="Italic">baccatum</Emphasis>

Molecular markers derived from the complete chloroplast genome can provide effective tools for species identification and phylogenetic resolution. Complete chloroplast (cp) genome sequences of Capsicum species have been reported. We herein report the complete chloroplast genome sequence of Capsicum baccatum var. baccatum, a wild Capsicum species. The total length of the chloroplast genome is 157,145 bp with 37.7 % overall GC content. One pair of inverted repeats, 25,910 bp in length, was separated by a small single-copy region (17,974 bp) and large single-copy region (87,351 bp). This region contains 86 protein-coding genes, 30 tRNA genes, 4 rRNA genes, and 11 genes contain one or two introns. Pair-wise alignments of chloroplast genome were performed for genome-wide comparison. Analysis revealed a total of 134 simple sequence repeat (SSR) motifs and 282 insertions or deletions variants in the C. baccatum var. baccatum cp genome. The types and abundances of repeat units in Capsicum species were relatively conserved, and these loci could be used in future studies to investigate and conserve the genetic diversity of the Capsicum species.     

Development of a Core Set from a Large Rice Collection using a Modified Heuristic Algorithm to Retain Maximum Diversity

A new heuristic approach was undertaken for the establishment of a core set for the diversity research of rice. As a result,107 entries were selected from the 10 368 characterized accessions. The core set derived using this new approach provideda good representation of the characterized accessions present in the entire collection. No significant differences for the mean, range, standard deviation and coefficient of variation of each trait were observed between the core and existing collections. We also compared the diversity of core sets established using this Heuristic Core Collection (HCC) approach with those of core sets established using the conventional clustering methods. This modified heuristic algorithm can also be used to select genotype data with allelic richness and reduced redundancy, and to facilitate management and use of large collections of plant genetic resources in a more efficient way.     

Characterization of microsatellite loci developed for <Emphasis Type="Italic">Amaranthus hypochondriacus</Emphasis> and their cross-amplifications in wild species

The present study reports isolation and characterization of 12 polymorphic microsatellite markers for Amaranthus hypochondriacus. A total of 92 alleles were detected across the 20 accessions, with an average of 7.7 alleles per locus. The observed (H _O ) and expected (H _E ) heterozygosity values ranged from 0 to 0.95 and from 0.49 to 0.92, respectively. At significance threshold (P < 0.05), nine loci deviated from Hardy-Weinberg equilibrium (HWE), whereas significant linkage disequilibria (LD) were observed between five pairs of loci. The 12 loci were successfully amplified in 18 other amaranth species representing cultivated grain and vegetable species, their putative progenitors and wild species. These results demonstrate wide potential applicability of these markers for the study of intra- and inter-specific genetic diversity as well as evolutionary relationships among cultivated and wild amaranths.     

Cerebral paragonimiasis: Clinicoradiological features and serodiagnosis using recombinant yolk ferritin

Cerebral paragonimiasis (CP), caused by aberrant migration of Paragonimus worms, frequently invokes serious illness. The causal relationship between the lesion characteristics and patients’ symptoms has poorly been understood. CP serodiagnosis has not been properly evaluated to date. A total of 111 CP cases were diagnosed in our laboratory between 1982 and 2003. This study retrospectively assessed the clinical and imaging characteristics of the 105 patients along with the evaluation of diagnostic potentials of recombinant P. westermani yolk ferritin (rPwYF) by enzyme-linked immunosorbent assay (ELISA) employing patients’ sera and cerebrospinal fluids (CSFs). We analyzed 60 male and 45 female patients; 50 early-stage patients with non-calcified enhancing nodule(s) (median age, 38 years; interquartile range [IQR], 24.75–52; median symptom duration, 0.75 years; IQR, 0.2–2) and 54 chronic cases having calcified lesion(s) (median age, 33 years; IQR, 25–41; median symptom duration, 10 years; IQR, 5–20). One patient showed a normal neuroimage. The patients were largely diagnosed in their 30s. The parietal lobe was most commonly affected, followed by occipital, frontal, and temporal lobes. Twenty-six patients had lesions encompassing ≥ two lobes. The patients complained mainly of seizures, headaches, hemiparesis, and focal neurologic deficits (P < 0.001). Seizures and visual defects were predominant in patients with calcified lesion(s) (P < 0.001). The diagnostic sensitivity and specificity of rPwYF against serum/CSF were 100%/97% and 97.2%/92.5%, respectively. The specific IgG antibody levels against rPwYF in sera and CSFs showed a positive correlation (r = 0.59). The clinical manifestations of the early-stage patients might be associated with cortical lesions or meningeal irritation, while those in the chronic stage were caused by conglomerated space-occupying lesions. rPwYF would be useful for the serodiagnosis of both early and chronic CP cases.