Protein Synthesis in the Developing Neocortex at Near-Atomic Resolution Reveals Ebp1-Mediated Neuronal Proteostasis at the 60S Tunnel Exit.

Protein synthesis must be finely tuned in the developing nervous system as the final essential step of gene expression. This study investigates the architecture of ribosomes from the neocortex during neurogenesis, revealing Ebp1 as a high-occupancy 60S peptide tunnel exit (TE) factor during protein synthesis at near-atomic resolution by cryoelectron microscopy (cryo-EM). Ribosome profiling demonstrated Ebp1-60S binding is highest during start codon initiation and N-terminal peptide elongation, regulating ribosome occupancy of these codons. Membrane-targeting domains emerging from the 60S tunnel, which recruit SRP/Sec61 to the shared binding site, displace Ebp1. Ebp1 is particularly abundant in the early-born neural stem cell (NSC) lineage and regulates neuronal morphology. Ebp1 especially impacts the synthesis of membrane-targeted cell adhesion molecules (CAMs), measured by pulsed stable isotope labeling by amino acids in cell culture (pSILAC)/bioorthogonal noncanonical amino acid tagging (BONCAT) mass spectrometry (MS). Therefore, Ebp1 is a central component of protein synthesis, and the ribosome TE is a focal point of gene expression control in the molecular specification of neuronal morphology during development.

Critical role of cyclic electron transport around photosystem I in the maintenance of photosystem I activity.

In angiosperms, cyclic electron transport around photosystem I (PSI) is mediated by two pathways that depend on the PROTON GRADIENT REGULATION 5 (PGR5) protein and the chloroplast NADH dehydrogenase-like (NDH) complex, respectively. In the Arabidopsis double mutants defective in both pathways, plant growth and photosynthesis are impaired. The pgr5-1 mutant used in the original study is a missense allele and accumulates low levels of PGR5 protein. In this study, we generated two knockout (KO) alleles, designated as pgr5-5 and pgr5-6, using the CRISPR-Cas9 technology. Although both KO alleles showed a severe reduction in P700 similar to the pgr5-1 allele, NPQ induction was less severely impaired in the KO alleles than in the pgr5-1 allele. In the pgr5-1 allele, the second mutation affecting NPQ size was mapped to ~21 cM south of the pgr5-1 locus. Overexpression of the pgr5-1 allele, encoding the glycine130-to-serine change, complemented the pgr5-5 phenotype, suggesting that the pgr5-1 mutation destabilizes PGR5 but that the mutant protein retains partial functionality. Using two KO alleles, we created the double mutants with two chlororespiratory reduction (crr) mutants defective in the NDH complex. The growth of the double mutants was notably impaired. In the double mutant seedlings that survived on the medium containing sucrose, PSI activity evaluated by the P700 oxidation was severely impaired, whereas PSII activity was only mildly impaired. Cyclic electron transport around PSI is required to maintain PSI activity.

Tailored multivalent peptide targeting the B-subunit pentamer of cholera toxin inhibits its intestinal toxicity by inducing aberrant transport of the toxin in cells.

Cholera toxin (Ctx) is a major virulence factor produced by Vibrio cholerae that can cause gastrointestinal diseases, including severe watery diarrhea and dehydration, in humans. Ctx binds to target cells through multivalent interactions between its B-subunit pentamer and the receptor ganglioside GM1 present on the cell surface. Here, we identified a series of tetravalent peptides that specifically bind to the receptor-binding region of the B-subunit pentamer using affinity-based screening of multivalent random-peptide libraries. These tetravalent peptides efficiently inhibited not only the cell-elongation phenotype but also the elevated cAMP levels, both of which are induced by Ctx treatment in CHO cells or a human colon carcinoma cell line (Caco-2 cells), respectively. Importantly, one of these peptides, NRR-tet, which was highly efficient in these two activities, markedly inhibited fluid accumulation in the mouse ileum caused by the direct injection of Ctx. In consistent, NRR-tet reduced the extensive Ctx-induced damage of the intestinal villi. After NRR-tet bound to Ctx, the complex was incorporated into the cultured epithelial cells and accumulated in the recycling endosome, affecting the retrograde transport of Ctx from the endosome to the Golgi, which is an essential process for Ctx to exert its toxicity in cells. Thus, NRR-tet may be a novel type of therapeutic agent against cholera, which induces the aberrant transport of Ctx in the intestinal epithelial cells, detoxifying the toxin.

Distinct contribution of two cyclic electron transport pathways to P700 oxidation.

Cyclic electron transport (CET) around Photosystem I (PSI) acidifies the thylakoid lumen and downregulates electron transport at the cytochrome b6f complex. This photosynthetic control is essential for oxidizing special pair chlorophylls (P700) of PSI for PSI photoprotection. In addition, CET depending on the PROTON GRADIENT REGULATION 5 (PGR5) protein oxidizes P700 by moving a pool of electrons from the acceptor side of PSI to the plastoquinone pool. This model of the acceptor-side regulation was proposed on the basis of the phenotype of the Arabidopsis (Arabidopsis thaliana) pgr5-1 mutant expressing Chlamydomonas (Chlamydomonas reinhardtii) plastid terminal oxidase (CrPTOX2). In this study, we extended the research including the Arabidopsis chlororespiratory reduction 2-2 (crr2-2) mutant defective in another CET pathway depending on the chloroplast NADH dehydrogenase-like (NDH) complex. Although the introduction of CrPTOX2 did not complement the defect in the acceptor-side regulation by PGR5, the function of the NDH complex was complemented except for its reverse reaction during the induction of photosynthesis. We evaluated the impact of CrPTOX2 under fluctuating light intensity in the wild-type, pgr5-1 and crr2-2 backgrounds. In the high-light period, both PGR5- and NDH-dependent CET were involved in the induction of photosynthetic control, whereas PGR5-dependent CET preferentially contributed to the acceptor-side regulation. On the contrary, the NDH complex probably contributed to the acceptor-side regulation in the low-light period but not in the high-light period. We evaluated the sensitivity of PSI to fluctuating light and clarified that acceptor-side regulation was necessary for PSI photoprotection by oxidizing P700 under high light.

Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts.

The chloroplast ATP synthase produces the ATP needed for photosynthesis and plant growth. The trans-membrane flow of protons through the ATP synthase rotates an oligomeric assembly of c subunits, the c-ring. The ion-to-ATP ratio in rotary F1F0-ATP synthases is defined by the number of c-subunits in the rotor c-ring. Engineering the c-ring stoichiometry is, therefore, a possible route to manipulate ATP synthesis by the ATP synthase and hence photosynthetic efficiency in plants. Here, we describe the construction of a tobacco (Nicotiana tabacum) chloroplast atpH (chloroplastic ATP synthase subunit c gene) mutant in which the c-ring stoichiometry was increased from 14 to 15 c-subunits. Although the abundance of the ATP synthase was decreased to 25% of wild-type (WT) levels, the mutant lines grew as well as WT plants and photosynthetic electron transport remained unaffected. To synthesize the necessary ATP for growth, we found that the contribution of the membrane potential to the proton motive force was enhanced to ensure a higher proton flux via the c15-ring without unwanted low pH-induced feedback inhibition of electron transport. Our work opens avenues to manipulate plant ion-to-ATP ratios with potentially beneficial consequences for photosynthesis.

Prognostic Value of the Geriatric Nutritional Risk Index in Previously Untreated Patients With Advanced NSCLC Treated With a Combination Therapy of Anti-PD-1/-PD-L1 Antibodies and Platinum-Based Chemotherapy: A Multicenter Retrospective Study.

INTRODUCTION: Combination therapy of anti-programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) antibodies and platinum-based chemotherapy has been widely used as a first-line treatment for patients with unresectable advanced non-small cell lung cancer (NSCLC) in clinical settings; however, prognostic biomarkers associated with survival outcomes have not been sufficiently investigated. METHODS: We enrolled 147 previously untreated patients with advanced NSCLC who were treated with a combination therapy of anti-PD-1/-PD-L1 antibodies and platinum-based chemotherapy at eight institutions in Nagano Prefecture between December 2018 and April 2023. We evaluated the prognostic value of the geriatric nutritional risk index (GNRI), a systemic inflammatory nutritional biomarker calculated from body weight and serum albumin level, for patients with NSCLC treated with a combination therapy of anti-PD-1/-PD-L1 antibodies and platinum-based chemotherapy. RESULTS: The cutoff value of the GNRI was set at 92. The high GNRI and low GNRI groups included 88 and 59 patients, respectively. The median follow-up period was 15.9 months. The overall survival (OS) in the high GNRI group was significantly longer than that in the low GNRI group (27.9 vs. 15.6 months, p = 0.015). Multivariate analysis revealed that a high GNRI was an independently favorable prognostic predictor for OS (hazard ratio, 1.73; 95% confidence interval, 1.06-2.86; p = 0.031). CONCLUSION: The present study demonstrates that the GNRI is a useful prognostic predictor in patients with NSCLC treated with a combination therapy of anti-PD-1/-PD-L1 antibodies and platinum-based chemotherapy in clinical settings.

Developing a Passive Dosing Method for Acute Aquatic Toxicity Tests of Cationic Surfactant Benzalkoniums (BACs).

Benzalkonium chlorides (BACs) have been of environmental concern due to their widespread use and potential harm. However, challenges arise in defining and controlling the exposure concentration (Cw) in aquatic toxicity tests involving BACs with a long alkyl chain (i.e., #C > 14). To address this, a novel passive dosing method was introduced in the 48 h-acute ecotoxicity test on Daphnia magna and compared to the conventional solvent-spiking method in terms of Cw stability and toxicity results. Among 13 sorbent materials tested for their sorption capacity, poly(ether sulfone) (PES) membrane was an optimal passive dosing reservoir, with equilibrium desorption of BACs to water achieved within 24 h. The Cw of BACs remained constant in both applied dosing methods during the test period. However, the Cw in solvent-spiking tests was lower than the nominal concentration for long-chain BACs, particularly at low exposure concentrations. Notably, the solvent-spiking tests indicated that the toxicity of BACs increased with alkyl chain length from C6 to 14, followed by a decline in toxicity from C14 to 18. In contrast, the passive dosing method displayed similar or slightly increasing toxicity levels of BACs from C14 to C18, indicating higher toxicity of C16 and C18-BACs than that inferred by the solvent spiking test. These findings emphasize the potential of applying this innovative passive dosing approach in aquatic toxicity tests to generate reliable and accurate toxicity data and support a comprehensive risk assessment of cationic surfactants.

The validation of a Japanese version of the New Freezing of Gait Questionnaire (NFOG-Q).

OBJECTIVE: This study aimed to develop a Japanese version of the New Freezing of Gait Questionnaire (NFOG-Q) and investigate its validity and reliability. METHODS: After translating the NFOG-Q according to a standardised protocol, 56 patients with Parkinson's disease (PD) were administered it. Additionally, the MDS-UPDRS parts II and III, Hoehn and Yahr (H&Y) stage, and number of falls over 1 month were evaluated. Spearman's correlation coefficients (rho) were used to determine construct validity, and Cronbach's alpha (α) was used to examine reliability. RESULTS: The interquartile range of the NFOG-Q scores was 10.0-25.3 (range 0-29). The NFOG-Q scores were strongly correlated with the MDS-UPDRS part II, items 2.12 (walking and balance), 2.13 (freezing), 3.11 (freezing of gait), and 3.12 (postural stability) and the postural instability and gait difficulty score (rho = 0.515-0.669), but only moderately related to the MDS-UPDRS item 3.10 (gait), number of falls, disease duration, H&Y stage, and time of the Timed Up-and-Go test (rho = 0.319-0.434). No significant correlations were observed between age and the time of the 10-m walk test. The internal consistency was excellent (α = 0.96). CONCLUSIONS: The Japanese version of the NFOG-Q is a valid and reliable tool for assessing the severity of freezing in patients with PD.

Successful maintenance treatment of disseminated nocardiosis with cerebral abscess in a severely immunocompromised patient allergic to trimethoprim-sulfamethoxazole using moxifloxacin and high-dose minocycline: A case report.

Nocardiosis in patients after allogeneic hematopoietic stem cell transplantation (HSCT) is rare, but is associated with a significant mortality risk. Although trimethoprim-sulfamethoxazole (TMP/SMX) remains the cornerstone of nocardiosis treatment, optimal alternative therapies for patients intolerant to TMP/SMX are not well-established. Herein, we report a case of disseminated nocardiosis with bacteremia and multiple lesions in the lungs and brain caused by Nocardia farcinica, in a 60-year-old man who had previously undergone allogeneic HSCT and was receiving immunosuppressants for severe chronic graft-versus-host disease. The patient received atovaquone for the prophylaxis of Pneumocystis pneumonia because of a previous serious allergic reaction to TMP/SMX. The patient was initially treated with imipenem/cilastatin and amikacin, which were later switched to ceftriaxone and amikacin based on the results of antimicrobial susceptibility testing. After switching to oral levofloxacin and a standard dose of minocycline, the patient experienced a single recurrence of brain abscesses. However, after switching to oral moxifloxacin and high-dose minocycline, the patient did not experience any relapses during the subsequent two years and seven months of treatment. In treating nocardiosis with brain abscesses, it is crucial to select oral antibiotics based on the antimicrobial susceptibility test results and pharmacokinetics, especially when TMP/SMX is contraindicated. A combination of oral moxifloxacin and high-dose minocycline could be a promising alternative therapy.

Non-chemical stresses do not strongly induce male offspring in Daphnia magna ascertained using the short-term juvenile hormone activity screening assay.

Juvenile hormone (JH), together with ecdysone, regulates molting, metamorphosis, growth, and reproduction in arthropods. The effects of its analogs used as insecticides on nontarget species are of concern. Since JH and JH analogs (JHAs) induce male offspring in daphnids, which generally reproduce by parthenogenesis, short-term JH activity screening assay (JHASA) using the male offspring ratio as an endpoint has been developed as a detection method for JHA. However, the production of male offspring is also induced by environmental stresses such as temperature, short-day length, overcrowding, and food limitation. Thus, it is vital to prevent non-chemical stresses from inducing male offspring during the test to detect chemicals with potential JH activity accurately. Therefore, we investigated the effects of temperature (low and high), hardness, high density with low feeding, and day length on male production utilizing JHASA. Male offspring were not strongly induced by any stresses in JHASA, although the male ratios of 4-12% were observed in the preculture under high density (≥70 daphnid/L) and constant darkness. The Clone A strain was relatively more sensitive to high density and day length compared with the strain from National Institute for Environmental Studies (NIES). The selection of strains that rarely produce males under non-chemical stresses and finding the culturing conditions for each strain appropriate for not-inducing male offspring are recommended to control and prevent male offspring induction during JHASA.

Prediction of chronic toxicity of pharmaceuticals in Daphnia magna by combining ortholog prediction, pharmacological effects, and quantitative structure-activity relationship.

To develop a method for predicting chronic toxicity of pharmaceuticals in Daphnia, we investigated the feasibility of combining the presence of drug-target orthologs in Daphnia magna, classification based on pharmacological effects, and ecotoxicity quantitative structure-activity relationship (QSAR) prediction. We established datasets on the chronic toxicity of pharmaceuticals in Daphnia, including information on therapeutic categories, target proteins, and the presence or absence of drug-target orthologs in D. magna, using literature and databases. Chronic toxicity was predicted using ecotoxicity prediction QSAR (Ecological Structure Activity Relationship and Kashinhou Tool for Ecotoxicity), and the differences between the predicted and measured values and the presence or absence of drug-target orthologs were examined. For pharmaceuticals without drug-target orthologs in D. magna or without expected specific actions, the ecotoxicity prediction QSAR analysis yielded acceptable predictions of the chronic toxicity of pharmaceuticals. In addition, a workflow model to assess the chronic toxicity of pharmaceuticals in Daphnia was proposed based on these evaluations and verified using an additional dataset. The addition of biological aspects such as drug-target orthologs and pharmacological effects would support the use of QSARs for predicting the chronic toxicity of pharmaceuticals in Daphnia.

Amelioration of nephritis in receptor for advanced glycation end-products (RAGE)-deficient lupus-prone mice through neutrophil extracellular traps.

The receptor for advanced glycation end-products (RAGE) is a pattern recognition receptor that regulates inflammation, cell migration, and cell fate. Systemic lupus erythematosus (SLE) is a chronic multiorgan autoimmune disease. To understand the function of RAGE in SLE, we generated RAGE-deficient (Ager-/-) lupus-prone mice by backcrossing MRL/MpJ-Faslpr/J (MRL-lpr) mice with Ager-/- C57BL/6 mice. In 18-week-old Ager-/- MRL-lpr, the weights of the spleen and lymph nodes, as well as the frequency of CD3+CD4-CD8- cells, were significantly decreased. Ager-/- MRL-lpr mice had significantly reduced urine albumin/creatinine ratios and markedly improved renal pathological scores. Moreover, neutrophil infiltration and neutrophil extracellular trap formation in the glomerulus were significantly reduced in Ager-/- MRL-lpr. Our study is the first to reveal that RAGE can have a pathologic role in immune cells, particularly neutrophils and T cells, in inflammatory tissues and suggests that the inhibition of RAGE may be a potential therapeutic strategy for SLE.

Highly Durable Spin Filter Switching Based on Self-Assembled Chiral Molecular Motor.

Chiral molecules have recently received renewed interest as highly efficient sources of spin-selective charge emission known as chiral-induced spin selectivity (CISS), which potentially offers a fascinating utilization of organic chiral materials in novel solid-state spintronic devices. However, a practical use of CISS remains far from completion, and rather fundamental obstacles such as (i) external controllability of spin, (ii) function durability, and (iii) improvement of spin-polarization efficiency have not been surmounted to date. In this study, these issues are addressed by developing a self-assembled monolayer (SAM) of overcrowded alkene (OCA)-based molecular motor. With this system, it is successfully demonstrated that the direction of spin polarization can be externally and repeatedly manipulated in an extremely stable manner by switching the molecular chirality, which is achieved by a formation of the covalent bonds between the molecules and electrode. In addition, it is found that a higher stereo-ordering architecture of the SAM of OCAs tailored by mixing them with simple alkanethiols considerably enhances the efficiency of spin polarization per a single OCA molecule. All these findings provide the creditable feasibility study for strongly boosting development of CISS-based spintronic devices that can simultaneously fulfill the controllability, durability, and high spin-polarization efficiency.

PTOX-dependent safety valve does not oxidize P700 during photosynthetic induction in the Arabidopsis pgr5 mutant.

Plastid terminal oxidase (PTOX) accepts electrons from plastoquinol to reduce molecular oxygen to water. We introduced the gene encoding Chlamydomonas reinhardtii (Cr)PTOX2 into the Arabidopsis (Arabidopsis thaliana) wild-type (WT) and proton gradient regulation5 (pgr5) mutant defective in cyclic electron transport around photosystem I (PSI). The accumulation of CrPTOX2 only mildly affected photosynthetic electron transport in the WT background during steady-state photosynthesis but partly complemented the induction of nonphotochemical quenching (NPQ) in the pgr5 background. During the induction of photosynthesis by actinic light (AL) of 130 µmol photons m-2 s-1, the high level of PSII yield (Y(II)) was induced immediately after the onset of AL in WT plants accumulating CrPTOX2. NPQ was more rapidly induced in the transgenic plants than in WT plants. P700 was also oxidized immediately after the onset of AL. Although CrPTOX2 does not directly induce a proton concentration gradient (ΔpH) across the thylakoid membrane, the coupled reaction of PSII generated ΔpH to induce NPQ and the downregulation of the cytochrome b6f complex. Rapid induction of Y(II) and NPQ was also observed in the pgr5 plants accumulating CrPTOX2. In contrast to the WT background, P700 was not oxidized in the pgr5 background. Although the thylakoid lumen was acidified by CrPTOX2, PGR5 was essential for oxidizing P700. In addition to acidification of the thylakoid lumen to downregulate the cytochrome b6f complex (donor-side regulation), PGR5 may be required for draining electrons from PSI by transferring them to the plastoquinone pool. We propose a reevaluation of the contribution of this acceptor-side regulation by PGR5 in the photoprotection of PSI.

Comparing the impact of the loss of patency between treatment with drug-coated balloon angioplasty and drug-eluting stent placement.

OBJECTIVE: To compare the results of endovascular treatment with drug-eluting stents (DES) and drug-coated balloons (DCB) in atherosclerotic lesions in the femoropopliteal artery, as well as to assess restenotic patterns. METHODS: Clinical data from 617 cases treated with DES or DCB for femoropopliteal diseases were analyzed in this multicenter, retrospective cohort study. From these, 290 DES and 145 DCB cases were extracted by propensity score matching. Outcomes investigated were 1- and 2-year primary patency, reintervention, and restenotic pattern and its impact on symptoms in each group. RESULTS: The primary patency rates at 1 and 2 years in the DES group were superior to those in the DCB group (84.8% and 71.1% vs 81.3% and 66.6%, P = .043), whereas there was no significant difference in freedom from target lesion revascularization (91.6% and 82.6% vs 88.3% and 78.8%, P = .13). Compared with what was measured before the index procedures, exacerbated symptoms, rate of occlusion, and an increase in the occluded length at loss of patency were more frequent in the DES group than in the DCB group. The odds ratios were 3.53 (95% confidence interval, 1.31-9.49; P = .012), 3.61 (1.09-11.9; P = .036), and 3.82 (1.15-12.7; P = .029), respectively. On the other hand, the frequency of an increase in lesion length and requirement of target lesion revascularization were similar between the two groups. CONCLUSIONS: Primary patency was significantly higher at 1 and 2 years in the DES than in the DCB group. However, DES were associated with exacerbated clinical symptoms and complicated lesion characteristics at the point of loss of patency.

Strong and Tunable Near-Infrared Circular Dichroism in Helical Tetrapyrrole Complexes.

The selective synthesis of nickel and copper complexes of 19-benzoyl-5,10,15-triphenyl-bilatrien-1-one (H2 TPBT) is reported, a molecule which crystallizes as a molecular helix of one-and-a-quarter which turns with a 5.7 Šradius and a 3.2 Špitch, and all 26 participating atoms are sp2 -hybridized. UV/vis, ECD, ESR and cyclic voltammetry experiments reveal a strong interaction between metal and ligand and partial radical character when copper is coordinated instead of nickel. Strong ECD absorption in the 800 nm range is found which, using TD-DFT calculations as well as literature spectra, is shown to be highly tunable both by metal coordination and variation of the aryl groups in the TPBT periphery. The radical character of the ligand in Cu(TPBT) enables rapid interconversion between (M)- and (P)-enantiomers, possibly via intermittent breakage of a Cu-N bond. The 19-benzoyl group kinetically stabilizes enantiopure (M/P)-Ni(TPBT). The results are interpreted with regard to the application as circularly polarized light (CPL) detectors as well as to the chirality-induced spin-selectivity (CISS) effect which is currently lacking a concise theoretical model.

Environmental RNA as a Noninvasive Tool for Assessing Toxic Effects in Fish: A Proof-of-concept Study Using Japanese Medaka Exposed to Pyrene.

Although environmental RNA (eRNA) is emerging as a noninvasive tool to assess the health status of aquatic macroorganisms, the potential of eRNA in assessing chemical hazards remain largely untested. In this study, we investigated the ability of eRNA to detect changes in gene expression in Japanese medaka fish (Oryzias latipes) in response to sublethal pyrene exposure, as a model toxic chemical. We performed standardized acute toxicity tests and collected eRNA from tank water and RNA from fish tissue after 96 h of exposure. Our results showed that over 1000 genes were detected in eRNA and the sequenced read counts of these genes correlated with those in fish tissue (r = 0.50). Moreover, eRNA detected 86 differentially expressed genes in response to pyrene, some of which were shared by fish RNA, including the suppression of collagen fiber genes. These results suggest that eRNA has the potential to detect changes in gene expression in fish in response to environmental stressors without the need for sacrificing or causing pain to fish. However, we also found that the majority of sequenced reads of eRNA (>99%) were not mapped to the reference medaka genome and they originated from bacteria and fungi, resulting in low sequencing depth. In addition, eRNA, in particular nuclear genes, was highly degraded with a median transcript integrity number (TIN) of <20. These limitations highlight the need for future studies to improve the analytical methods of eRNA application.

An 11-Beta Hydroxysteroid Dehydrogenase Type 1 Inhibitor, JTT-654 Ameliorates Insulin Resistance and Non-obese Type 2 Diabetes.

11ß-Hydroxysteroid dehydrogenase type 1 (11ß-HSD1) is the only enzyme that converts inactive glucocorticoids to active forms and plays an important role in the regulation of glucocorticoid action in target tissues. JTT-654 is a selective 11ß-HSD1 inhibitor and we investigated its pharmacological properties in cortisone-treated rats and non-obese type 2 diabetic Goto-Kakizaki (GK) rats because Asians, including Japanese, are more likely to have non-obese type 2 diabetics. Systemic cortisone treatment increased fasting plasma glucose and insulin levels and impaired insulin action on glucose disposal rate and hepatic glucose production assessed by hyperinsulinemic-euglycemic clamp, but all these effects were attenuated by JTT-654 administration. Cortisone treatment also reduced basal and insulin-stimulated glucose oxidation in adipose tissue, increased plasma glucose levels after administration of the pyruvate, the substrate of gluconeogenesis, and increased liver glycogen content. Administration of JTT-654 also inhibited all of these effects. Cortisone treatment decreased basal and insulin-stimulated 2-deoxy-D-[1-3H]-glucose uptake in 3T3-L1 adipocytes and increased the release of free fatty acids and glycerol, a gluconeogenic substrate, from 3T3-L1 adipocytes, and JTT-654 significantly attenuated these effects. In GK rats, JTT-654 treatment significantly reduced fasting plasma glucose and insulin levels, enhanced insulin-stimulated glucose oxidation in adipose tissue, and suppressed hepatic gluconeogenesis as assessed by pyruvate administration. These results demonstrated that glucocorticoid was involved in the pathology of diabetes in GK rats, as in cortisone-treated rats, and that JTT-654 ameliorated the diabetic conditions. Our results suggest that JTT-654 ameliorates insulin resistance and non-obese type 2 diabetes by inhibiting adipose tissue and liver 11ß-HSD1.

Development of a microplate-based novel toxicity bioassay using Chlorophyta and Phaeophyceae macroalgae.

Macroalgae are one of the main producers in marine environments. However, only a few toxicity test methods have been established that use reference strains of macroalgae to evaluate the effects of chemicals on the growth and reproduction of macroalgae to monitor water quality. We selected reference strains of Chlorophyta, Ulva aragoënsis; Phaeophyceae, Ectocarpus siliculosus; and wakame, Undaria pinnatifida, as test species to establish a microplate-based method to investigate the toxicity of potassium dichromate, 3,5-dichlorophenol, and two common herbicides (diuron and simazine). We determined the growth of the three macroalgae in their early life stages and during the sporangia formation stage in E. siliculosus under laboratory conditions. We observed that the growth and sporangia formation in these algae were impaired in a dose-dependent manner. Additionally, we investigated the sensitivity of these macroalgae by comparing the toxicity values of toxicants used in this study with those obtained from a database. Compared to other microalgae and plant species, macroalgae showed a relatively high sensitivity to organic compounds, including herbicides. Growth tests using U. aragoënsis and E. siliculosus produced reliable results at 0-32 and 25-32 practical salinity units (PSU), respectively. The tests established in this study could test the toxicity of chemical substances in macroalgae and are thus expected to contribute to a better understanding of the environmental risks of chemical substances on aquatic biota. The tests could be applied to all effluent toxicity tests used for the management of seawater and brackish water quality.

Quantitative analyses of misclassification rates in the hazard classification of environmental chemicals: Evaluation of procedures for deriving predicted no-effect concentrations in the Chemical Substance Control Law in Japan.

The quality of chemical management depends more or less on practical procedures used to assess chemicals. This study quantitatively assessed the efficacy of a derivation procedure for calculating no-effect concentrations for screening assessment of environmental hazards under the Chemical Substance Control Law in Japan. We first evaluated the derivation procedure by applying a series of test ecotoxicity datasets to the procedure and calculating the resulting misclassification rates of the hazardous class of chemicals. In this study, a chemical was deemed to have been misclassified if its classification differed from its classification based on the full dataset (chronic toxicity data for three trophic levels), which was defined as the correct assignment. We also calculated the effects of additional uncertainty factors to decrease the variance (i.e., to improve the consistency) of the misclassification rates among cases with different data availability in the derivation procedure. The results showed that the derivation procedure resulted in very high rates of misclassification when only particular sets of ecotoxicity data were available (e.g., only chronic toxicity data of algae were available). Our analyses also showed that the use of additional uncertainty factors improved the consistency of the misclassification rates within the derivation procedure. Our study presents a broadly applicable calculation framework for quantifying error rates in assessment procedures and serves as a case study for future development and reforms of chemical assessment processes and policies, while additional analyses using more extensive ecotoxicity data with various modes of actions are needed in the future.