Expression of ASC splice variant found in Japanese patients with palindromic rheumatism is regulated by rs8056505 single nucleotide polymorphism and interleukin-1 beta.

BACKGROUND: Palindromic rheumatism (PR) is an infrequent form of periodic arthritis. Based on the similarity of the pathogenesis of PR to autoinflammatory syndromes, we previously found that the dominant-active splice variant of the inflammasome adaptor protein, apoptosis-associated speck-like protein containing a CARD (ASC), which lacks exon 2 (Δexon2), is expressed in Japanese patients with PR. OBJECTIVE: Elucidation of the mechanism of Δexon2 ASC production and the effect of IL-1ß on splicing. METHODS: The genomic DNA of Japanese patients with PR was sequenced. The effect of the observed single nucleotide polymorphisms (SNPs) on ASC splicing was determined via exon trapping using THP-1 cells stimulated with interleukin-1 beta (IL-1ß) or ceramide. To investigate the genes that affect alternative splicing via IL-1ß, we analyzed the transcriptome of IL-1ß-treated THP-1 cells using RNA sequencing. RESULTS: We found the rs8056505 A->G SNP located in the 5'-untranslated region of the genomic ASC gene in patients and that Δexon2 expression was induced by this SNP, whereas it was suppressed by IL-1ß or ceramide. We detected 131,426 transcripts and identified 52 differentially expressed genes (DEGs) consisting of 41 downregulated genes and 11 upregulated genes in IL-1ß-stimulated THP-1 cells. The splicing-related gene MASCRNA was the most significantly induced gene by IL-1ß. CONCLUSIONS: We propose a cyclic expression model in which ASC alternates between wild-type and Δexon2 expression regulated by the rs8056505 G allele and splicing factors induced by IL-1ß. This cycle may be correlated with the formation of periodic PR pathologies.

Expression of a PYCARD/ASC variant lacking exon 2 in Japanese patients with palindromic rheumatism increases interleukin-1ß secretion.

BACKGROUND: Palindromic rheumatism (PR) is a rare periodic arthritis characterized by relapsing short episodes of arthritis. Although the pathogenesis of PR is still unclear, the clinical condition is similar to that of autoinflammatory diseases caused by dysregulation of inflammasome-related genes. OBJECTIVE: We analyzed the inflammasome adapter PYD and CARD domain-containing protein/apoptosis-associated speck-like protein containing a CARD (PYCARD/ASC) in Japanese patients with PR. METHODS: Serum interleukin (IL)-1ß concentrations in three Japanese patients with PR were measured. We also cloned PYCARD/ASC cDNA variants and expressed them in THP-1 cells to determine their effects on inflammasome activity following stimulation with phorbol 12-myristate 13-acetate and monosodium urate. Lysates of recombinant THP-1 cells were subjected to co-immunoprecipitation assays. RESULTS: Serum IL-1ß concentrations were significantly elevated in patients with PR, and a splice variant of PYCARD/ ASC mRNA lacking exon 2 (Δexon2) was dominantly expressed compared with that in controls. Moreover, IL-1ß secretion was significantly increased in THP-1 cells expressing Δexon2PYCARD/ASC compared with that in cells expressing the wild-type protein. The amount of NLRP3 bound to Δexon2PYCARD/ASC was increased after stimulation, whereas that bound to the wild-type protein was decreased. There were no differences in caspase-1 binding. CONCLUSIONS: Δexon2 PYCARD/ASC was associated with the pathogenesis of PR.

A variant of death-receptor 3 associated with rheumatoid arthritis interferes with apoptosis-induction of T cell.

Rheumatoid arthritis (RA) is a chronic polyarthritis of unknown etiology. To unravel the molecular mechanisms in RA, we performed targeted DNA sequencing analysis of patients with RA. This analysis identified a variant of the death receptor 3 (DR3) gene, a member of the family of apoptosis-inducing Fas genes, which contains four single-nucleotide polymorphisms (SNPs) and a 14-nucleotide deletion within exon 5 and intron 5. We found that the deletion causes the binding of splicing regulatory proteins to DR3 pre-mRNA intron 5, resulting in a portion of intron 5 becoming part of the coding sequence, thereby generating a premature stop codon. We also found that this truncated DR3 protein product lacks the death domain and forms a heterotrimer complex with wildtype DR3 that dominant-negatively inhibits ligand-induced apoptosis in lymphocytes. Myelocytes from transgenic mice expressing the human DR3 variant produced soluble truncated DR3, forming a complex with TNF-like ligand 1A (TL1A), which inhibited apoptosis induction. In summary, our results reveal that a DR3 splice variant that interferes with ligand-induced T cell responses and apoptosis may contribute to RA pathogenesis.

Genetic Rare Variants Affecting Multiple Pathways in Japanese Patients with Palindromic Rheumatism.

Palindromic rheumatism (PR) is a type of cryptogenic paroxysmal arthritis. Several genes may be involved in PR pathogenesis; however, conducting comprehensive case-control genetic studies for PR poses challenges owing to its rarity as a disease. Moreover, case-control studies may overlook rare variants that occur infrequently but play a significant role in pathogenesis. This study aimed to identify disease-related genes in Japanese patients with PR using whole-genome sequencing (WGS) and rare-variant analysis. Genomic DNA was obtained from two familial cases and one sporadic case, and it was subjected to WGS. WGS data of 104 healthy individuals obtained from a public database were used as controls. We performed data analysis for rare variants on detected variants using SKAT-O, KBAC, and SKAT, and subsequently defined significant genes. Significant genes combined with variants shared between the cases were defined as disease-related genes. We also performed pathway analysis for disease-related genes using Reactome. We identified 2,695,244 variants shared between cases; after excluding polymorphisms and noise, 74,640 variants were detected. We identified 540 disease-related genes, including 1,893 variants. Furthermore, we identified 32 significant pathways. Our results indicate that the detected genes and pathways in this study may be involved in PR pathogenesis.

Role of the MICA polymorphism in systemic lupus erythematosus.

OBJECTIVE: To study the genetic contribution of major histocompatibility complex class I polypeptide-related sequence A (MICA), important in natural killer (NK) cell function, in patients with systemic lupus erythematosus (SLE). METHODS: Japanese patients with SLE (n=716), those with rheumatoid arthritis (RA) (n=327), and healthy control subjects (n=351) were genotyped for the Val129 Met polymorphism (rs1051792) and transmembrane (TM) alanine-encoding GCT repeats, termed A4, A5, A5.1, A6, and A9, in the MICA gene. Recombinant human MICA-GST fusion proteins were tested on the NK cell line NK92MI for the expression of NK group 2, member D (NKG2-D), NK cell-mediated cytotoxicity, and interferon-γ (IFNγ) production. RESULTS: The MICA 129Met allele, TMA9 allele, and 129Met/Met genotype were positively associated with SLE (corrected P [Pcorr]=0.01 and odds ratio [OR] 1.3, Pcorr=0.003 and OR 1.6, and Pcorr=0.02 and OR 1.8, respectively), while the MICA 129Val allele was negatively associated with SLE (Pcorr=0.01, OR 0.8). The MICA 129Met;A9 haplotype was also associated with SLE (Pcorr=0.0006, OR 1.8), and there was an additive genetic effect between the MICA 129Met;A9 haplotype and HLA-DRB1*15:01. When NK92MI cells were incubated in vitro with recombinant human disease-associated 129Met;A9 (the combination of polymorphisms at 129Met and TMA9), expression of NKG2-D on NK92MI cells and cytotoxicity of the NK cells were inhibited, but production of IFNγ from NK92MI cells was enhanced. CONCLUSION: The MICA polymorphism is genetically associated with SLE, and MICA appears to contribute to the pathogenesis of SLE by modulating NK cell function.

Mammalian clock gene Cryptochrome regulates arthritis via proinflammatory cytokine TNF-alpha.

The mammalian clock genes, Period and Cryptochrome (Cry), regulate circadian rhythm. We show that circadian rhythmicity and rhythmic expression of Period in the nuclei of inflammatory synovial cells and spleen cells are disturbed in mouse models of experimental arthritis. Expressions of other clock genes, Bmal1 and Dbp, are also disturbed in spleen cells by arthritis induction. Deletion of Cry1 and Cry2 results in an increase in the number of activated CD3(+) CD69(+) T cells and a higher production of TNF-alpha from spleen cells. When arthritis is induced, Cry1(-/-)Cry2(-/-) mice develop maximal exacerbation of joint swelling, and upregulation of essential mediators of arthritis, including TNF-alpha, IL-1beta and IL-6, and matrix metalloproteinase-3. Wee-1 kinase is solely upregulated in Cry1(-/-)Cry2(-/-) mice, in line with upregulation of c-Fos and Wee-1 kinase in human rheumatoid arthritis. The treatment with anti-TNF-alpha Ab significantly reduced the severity and halted the progression of the arthritis of Cry1(-/-)Cry2(-/-) mice and vice versa, ectopic expression of Cry1 in the mouse embryonic fibroblast from Cry1(-/-)Cry2(-/-) mice significantly reduced the trans activation of TNF-alpha gene. Thus, the biological clock and arthritis influence each other, and this interplay can influence human health and disease.

Mathematical basis of affected sib-pair analysis: an extension to X-linked loci.

Most clinical genetic studies are done without knowing their mathematical basis. However, because the results of such studies rely on the correctness of the mathematical calculations involved, we cannot ignore the mathematics of genetic studies. In this study, the mathematical basis of the sib-pair method, which has been widely used in recent genome-wide studies, was extended to studies focusing on the X chromosome, and then applied to study a clinical microsatellite marker on the X chromosome. Our calculation involves classifying marker types on the X chromosome for an affected sib-pair and an unaffected sib, together with their sexual information and the possible parental marker types applicable to a genome-wide genetic study. The method proposed in this study was then applied to 41 Japanese rheumatoid families, and the locus DXS984 was found to be most likely to be linked with rheumatoid arthritis (RA). This locus, which we found nicely, was also highlighted in a previous study that used the Mapmaker/sibs program, so we can conclude that our calculation provides a solid foundation for understanding and confirming the results obtained using the sib-pair method.

Prospective study of methotrexate treatment for rheumatoid arthritis treated legitimately according to the government recommended 8 mg/week dose.

Clinical squeal of the treatment of rheumatoid arthritis patients with methotrexate (MTX) according to the Japanese government recommended dose of 8 mg/week was evaluated prospectively. A total of 176 patients with active RA attending Konan Kakogawa Hospital and Kobe University Hospital were enrolled. Patients' profile at the start of study was Class 2.0 +/- 1.1 and X-ray stage 2.6 +/- 1.0. The effects of MTX treatment were evaluated by the American College of Rheumatology (ACR) core set, disease activity score of 28 joints (DAS28), and European League Against Rheumatism (EULAR) response criteria. A modified Sharp method was used to evaluate the radiographs. The improvement in the clinical signs and symptoms of the ACR core set was maintained for a 24-month period (p < 0.05). The ACR20/50/70 and DAS28 were also improved at the 12- and 24-month assessments. However, 82 of 130 patients (63.5%) were found to be nonresponders at 24 months of MTX therapy, as evaluated by EULAR response criteria. The X-ray study showed that joint destruction progressed despite the treatment. Thus, long-term MTX treatment performed in accordance with the Japanese 8 mg/week regimen appears to be favorable in terms of the signs and symptoms of RA; however, it is clearly insufficient for and cannot halt the progression of rheumatic joint destruction.

CD44v8-10 and CD44s Are Age-dependently Expressed in Primary Cultured Papillary Thyroid Carcinoma Cells and Are Associated with Cell Proliferation.

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy, arising from follicular cells, and accounts for more than 80% of all thyroid malignant tumors. Although age is the strongest prognostic factor of PTC, and various cut-off ages (40-55 years) were suggested in previous studies, the molecular mechanisms causing age-related changes of PTC cell proliferation remain unclear. CD44 is a major cell surface receptor for hyaluronate and is known as a cancer stem cell marker. However, the association between CD44 and PTC is still unknown. Therefore, we determined the proliferation of primary cultured cells obtained from patients with PTC, and the CD44 mRNA expression profile to elucidate age-related association of CD44 with PTC. The results showed that cell proliferation was significantly decreased according to age. We also found that CD44v8-10 and CD44 splice variants were expressed dominantly in patients with PTC. Moreover, the CD44v8-10/CD44s mRNA expression ratio was significantly increased according to age, and there was a significant negative correlation between this expression ratio and cell proliferation. Our findings suggest that the CD44v8-10/CD44s expression ratio in PTC cells is useful for screening for aggressive PTC and may provide clinically valuable information.

Synthesis and insect antifeedant activity of aurones against Spodoptera litura larvae.

A series of aurones were prepared from various phenols via phenoxy acetic acids and coumaranones and evaluated for insect antifeedant activity against the common cutworm (Spodoptera litura). The naturally occurring aurone was most active at an ED50 of 0.12 micromol/cm2. The synthetic precursor, coumaranones, showed that the introduction of methoxyl and methyl groups to the benzene ring increased insect antifeedant activity. Similarly, the tested aurones showed that the introduction of methoxyl group to the A and/or B rings increased the insect antifeedant activity, but 4,5,6- and 3',4',5'-trisubstituted compounds did not show this activity in this test. The hydroxylation of aurones in the B ring should be disadvantageous for insect antifeedant activity against S. litura. Although the melting points did not correlate well with the insect antifeedant activity, compounds that were nearly inactive had high melting points. A significant correlation was noted between biological activity (pED50) and a hydrogen-bonding parameter calculated from the Rf value obtained from SiOH thin-layer chromatography and a lipophilicity parameter (log k) calculated from the retention time in ODS high-performance liquid chromatography. The respective correlation coefficients (r) were -0.83 and -0.70. The introduction of alkoxy and alkyl groups along with adequate hydrogen bonding seems to contribute to the antifeedant activity of the compounds tested.

Electrochemical Synthesis of Dihydrobenzofurans and Evaluation of Their Insect Antifeedant Activities.

Electrochemically synthesized dihydrobenzofurans were evaluated for their insect antifeedant activities against phytophagous insects. They were prepared through the coupling reactions of various alkenes with a phenoxy cation generated by oxidation near the cathode in the electrolytic reaction. The insect antifeedant activities of these synthetic dihydrobenzofurans were evaluated in the common cutworm (Spodoptera litura) and diamond back moth (Plutella xylostella) with the dual choice leaf disk bioassay method. The insect antifeedant activities of most of the acetophenone-type dihydrobenzofurans were strong, while those of derivatives with a t-butyl group were weaker. The biological activities in insect species differed with the structural features of the compounds.

Human wee1 kinase is directly transactivated by and increased in association with c-Fos/AP-1: rheumatoid synovial cells overexpressing these genes go into aberrant mitosis.

Wee1 kinase downregulates the M-phase promoting factor, a complex of cdc2 and cyclin B kinase, that controls mitotic cell division. We isolated human wee1 kinase gene promoter and found that it contained one AP-1-binding motif in its promoter region (5'-CGAGTCA-3'; -823/-817), through which wee1 kinase gene was directly transactivated by c-Fos/AP-1. In rheumatoid synovial cells, wee1 kinase was increased in conjunction with the increase of c-Fos/AP-1 and the substrate of wee1, cdc2, was phosphorylated. The amount of wee1 and c-Fos and the phosphorylation of cdc2 were decreased after treatment of the cells with an inhibitor of AP-1, curcumin. A significant proportion of cultured synovial cells of the patients with rheumatoid arthritis, but not those of osteoarthritis, shifted to a tetraploid (4C) state upon long-term culture. Thus, human wee1 kinase gene is directly transactivated by and increased in association with c-Fos/AP-1, and rheumatoid synovial cells overexpressing these genes go into aberrant mitosis.

Biosynthesis of pyrethrin I in seedlings of Chrysanthemum cinerariaefolium.

The biosynthetic pathway to natural pyrethrins in Chrysanthemum cinerariaefolium seedlings was studied using [1-13C]d-glucose as a precursor, with pyrethrin I isolated using HPLC from a leaf extract. The 13C NMR spectrum of pyrethrin I from the precursor-administered seedlings indicated that the acid moiety was biosynthesized from d-glucose via 2-C-methyl-d-erythritol 4-phosphate, whereas the alcohol moiety was possibly biosynthesized from linolenic acid.

Diverse actions of neonicotinoids on chicken alpha7, alpha4beta2 and Drosophila-chicken SADbeta2 and ALSbeta2 hybrid nicotinic acetylcholine receptors expressed in Xenopus laevis oocytes.

The 2-nitroimino-imidazolidine and related moieties are structural features of neonicotinoid insecticides acting on nicotinic acetylcholine receptors (nicotinic AChRs). To evaluate these moieties in neonicotinoid interactions with nicotinic AChR alpha subunits, the actions of imidacloprid and related compounds on the chicken alpha7, alpha4beta2 and Drosophila melanogaster-chicken hybrid (SADbeta2 and ALSbeta2) receptors expressed in Xenopus laevis oocytes were studied by voltage-clamp electrophysiology. Imidacloprid and nitenpyram were partial agonists and a nitromethylene analog of imidacloprid (CH-IMI) was a full agonist of the alpha7 receptor, whereas their agonist actions on the alpha4beta2 receptor were very weak, contrasting with full agonist actions of DN-IMI, a desnitro derivative of imidacloprid. The neonicotinoids and DN-IMI were either full or partial agonists of the SADbeta2 receptors. Nitenpyram and DN-IMI were partial agonists of the ALSbeta2 receptor, whereas imidacloprid and CH-IMI scarcely activated the ALSbeta2 receptor. Imidacloprid and CH-IMI in fact suppressed ACh-induced responses of the ALSbeta2 receptor, whereas imidacloprid potentiated and CH-IMI suppressed ACh-induced responses of the alpha4beta2 receptor. These results suggest that interactions with alpha subunits of the 2-nitroimino-imidazolidine moiety of imidacloprid play a role in determining not only agonist and antagonist actions on all four receptors, but also the potentiation of ACh-induced responses of the alpha4beta2 receptor.

Effects of mutations of a glutamine residue in loop D of the alpha7 nicotinic acetylcholine receptor on agonist profiles for neonicotinoid insecticides and related ligands.

1. Neonicotinoid insecticides are agonists of insect nicotinic acetylcholine receptors (AChRs) and show selective toxicity for insects over vertebrates. To elucidate the molecular basis of the selectivity, amino acid residues influencing neonicotinoid sensitivity were investigated by site-directed mutagenesis of the chicken alpha7 nicotinic AChR subunit, based on the crystal structure of an ACh binding protein (AChBP). 2. In the ligand binding site of AChBP, Q55 in loop D is close to Y164 in loop F that corresponds to G189 of the alpha7 nicotinic receptor. Since Q55 of AChBP is preserved as Q79 in the alpha7 nicotinic receptor and the G189D and G189E mutations have been found to reduce the neonicotinoid sensitivity, we investigated effects of Q79E, Q79K and Q79R mutations on the neonicotinoid sensitivity of the alpha7 receptor expressed in Xenopus laevis oocytes to evaluate contributions of the glutamine residue to nicotinic AChR-neonicotinoid interactions. 3. The Q79E mutation markedly reduced neonicotinoid sensitivity of the alpha7 nicotinic AChR whereas the Q79K and Q79R mutations increased sensitivity, suggesting electronic interactions of the neonicotinoids with the added residues. 4. By contrast, the Q79E mutation scarcely influenced responses of the alpha7 nicotinic receptor to ACh, (-)-nicotine and desnitro-imidacloprid (DN-IMI), an imidacloprid derivative lacking the nitro group, whereas the Q79K and Q79R mutations reduced the sensitivity to these ligands. The results indicate that the glutamine residue of the alpha7 nicotinic receptor is likely to be located close to the nitro group of the insecticides in the nicotinic receptor-insecticide complex.

Metabolism of 26,26,26,27,27,27-F6-1alpha,25-dihydroxyvitamin D3 by CYP24: species-based difference between humans and rats.

The compound 26,26,26,27,27,27-F(6)-1alpha,25(OH)(2)D(3) is a hexafluorinated analog of the active form of Vitamin D(3). The enhanced biological activity of F(6)-1alpha,25(OH)(2)D(3) is considered to be related to a decreased metabolic inactivation of the compound in target tissues such as the kidneys, small intestine, and bones. Our previous study demonstrated that CYP24 is responsible for the metabolism of F(6)-1alpha,25(OH)(2)D(3) in the target tissues. In this study, we compared the human and rat CYP24-dependent metabolism of F(6)-1alpha,25(OH)(2)D(3) by using the Escherichia coli expression system. In the recombinant E. coli cells expressing human CYP24, bovine adrenodoxin and NADPH-adrenodoxin reductase, F(6)-1alpha,25(OH)(2)D(3) was successively converted to F(6)-1alpha,23S,25(OH)(3)D(3), F(6)-23-oxo-1alpha,25(OH)(2)D(3), and the putative ether compound with the same molecular mass as F(6)-1alpha,25(OH)(2)D(3). The putative ether was not observed in the recombinant E. coli cells expressing rat CYP24. These results indicate species-based difference between human and rat CYP24 in the metabolism of F(6)-1alpha,25(OH)(2)D(3). In addition, the metabolite with a cleavage at the C(24)z.sbnd;C(25) bond of F(6)-1alpha,25(OH)(2)D(3) was detected as a minor metabolite in both human and rat CYP24. Although F(6)-1alpha,23S,25(OH)(3)D(3) and F(6)-23-oxo-1alpha,25(OH)(2)D(3) had a high affinity for Vitamin D receptor, the side-chain cleaved metabolite and the putative ether showed extremely low affinity for Vitamin D receptor. These findings indicate that human CYP24 has a dual pathway for metabolic inactivation of F(6)-1alpha,25(OH)(2)D(3) while rat CYP24 has only one pathway. Judging from the fact that metabolism of F(6)-1alpha,25(OH)(2)D(3) in rat CYP24-harboring E. coli cells is quite similar to that in the target tissues of rat, the metabolism seen in human CYP24-harboring E. coli cells appear to exhibit the same metabolism as in human target tissues. Thus, this recombinant system harboring human CYP24 appears quite useful for predicting the metabolism and efficacy of Vitamin D analogs in human target tissues before clinical trials.

Combinatorial mutations in loops D and F strongly influence responses of the alpha7 nicotinic acetylcholine receptor to imidacloprid.

The nitro group of a neonicotinoid, imidacloprid, plays a key role in its selective actions on insect nicotinic acetylcholine receptors (nicotinic AChRs) and is postulated to bind close to residues Q79 in loop D and G189 in loop F of the chicken alpha7 nicotinic AChR. To evaluate the relative contributions of these residues to interactions with imidacloprid, Q79 and G189 were replaced in tandem by first basic then acidic residues. Changes in the currents evoked by imidacloprid and acetylcholine (ACh) on the alpha7 wild type and mutant receptors expressed in Xenopus laevis oocytes were investigated using two-electrode voltage clamp electrophysiology. An increase in the efficacy of imidacloprid for the alpha7 receptor resulting from the Q79K and Q79R mutations was suppressed by a G189E mutation in loop F. However, the increases in efficacy resulting from such Q79 mutations were scarcely influenced by a G189D substitution. Three-dimensional modeling of the alpha7 nicotinic AChR, based on the acetylcholine-binding protein (AChBP) of Lymnaea stagnalis, suggests that the reduced efficacy of imidacloprid following the G189E mutation is likely to result from carboxylate interference with the electronic interactions between the nitro group of imidacloprid and the basic residues in loop D.

Roles of loop C and the loop B-C interval of the nicotinic receptor alpha subunit in its selective interactions with imidacloprid in insects.

To elucidate the mechanism of selective action of imidacloprid on insect nicotinic acetylcholine receptors (nAChRs), we examined the roles of loop C and the loop B-C interval region in receptor interactions with imidacloprid. The P242E mutation in loop C of the Drosophila SAD subunit (the second alpha-like Drosophila nicotinic acetylcholine receptor subunit, also called Dalpha2 subunit) reduced imidacloprid sensitivity of the SAD-chicken beta2 hybrid nAChR, whereas the E219P mutation of the alpha4 subunit increased the imidacloprid sensitivity of the alpha4beta2 nAChR. Deletion of the loop B-C interval region from the SAD subunit enhanced the effect of the P242E mutation on the SADbeta2 hybrid nAChR, suggesting important roles of the regions investigated in the nAChR-imidacloprid interactions.

Antifeedant activity of an anthraquinone aldehyde in Galium aparine L. against Spodoptera litura F.

The insect antifeedant anthraquinone aldehyde nordamnacanthal (1,3-dihydroxy-anthraquinone-2-al) was identified in Galium aparine L., and isolated from the root powder of akane (Rubia akane), a member of the Rubiaceae. Structure-activity relationship (SAR) studies using a series of anthraquinone analogues suggested that the aldehyde group on the anthraquinone was more important than the quinone moiety for antifeedant activity against the common cutworm (Spodoptera litura). High levels of nordamnacanthal were found in the seed leaf stage and in callus tissue induced from seedlings of G. aparine, but its concentration decreased with plant development. Since these compounds are natural pigments for dying textiles, we also evaluated the antifeedant activity against the carpet beetle (Attagenus japonicus ), a textile pest was also evaluated. While nordamnacanthal had strong antifeedant activity against the common cutworm, it did not show any antifeedant activity against the carpet beetle. The most effective antifeedant against the carpet beetle was the major constituent in the extract of R. trictorum, lucidin-3-O-primeveroside, a food pigment.

Evaluation of calcium-alginate gel as an artificial diet medium for bioassays on common cutworms.

A calcium-alginate gel diet was developed for Spodoptera litura larvae, and its reliability as a carrier for incorporating antifeedants as well as insecticides was investigated. The alginate gel diet was prepared with a simple protocol, which does not involve any heating process. When tested using this diet, acephate, a Bacillus thuringiensis endotoxin formulation and rotenone reproducibly showed insecticidal activity against the larvae, while neem oil and scabequinone deterred the larval feeding effectively. However, not only the insecticidal activity of acephate but also the antifeedant activity of neem oil was reduced by replacing the alginate component by agar in the diet, suggesting the usefulness of the alginate gel diet as an assay tool for testing a broad range of samples against the larvae.