Background and Aim: We evaluated the usefulness of serum cytokeratin 18 fragment (CK18-F) as a noninvasive biomarker in differentiating nonalcoholic steatohepatitis (NASH) from nonalcoholic fatty liver (NAFL) since the prognosis of the 2 diseases differ. Methods: 116 Japanese patients with nonalcoholic fatty liver disease (NAFLD) proven by liver biopsy were studied. Histological findings were classified according to the NAFLD activity score (NAS) proposed by the Nonalcoholic Steatohepatitis Clinical Research Network. The correlation between histological findings and serum CK18-F levels was investigated. Results: Serum CK18-F levels showed a positive correlation with histologic steatosis (ρ = 0.271, P = 0.0033), inflammation (ρ = 0.353, P = 0.0005), ballooning (ρ = 0.372, P = 0.0001), and the total NAS (ρ = 0.474, P = 2.68 × 10-7). The serum CK18-F level was significantly lower for NAFL (NAS ≤ 2) than for borderline NASH (NAS of 3-4) or definite NASH (NAS ≥ 5) (P = 0.0294, P = 1.163 × 10-5, respectively). The serum CK18-F level was significantly higher for definite NASH than for borderline NASH (P = 0.0002). The area under the receiver operating characteristic curve of serum CK18-F to predict the presence of NAFL and definite NASH was 0.762 and 0.757, respectively. The optimal cut-off point of serum CK18-F for NAFL and definite NASH was 230 and 270 U/L, respectively. The sensitivity, specificity, positive predict value, and negative predict value of serum CK18-F for NAFL were 0.89, 0.65, 0.34, and 0.97, and those for definite NASH were 0.64, 0.76, 0.72, and 0.67, respectively. Accuracies of diagnosis for both NAFL and definite NASH were 0.70. Conclusions: Serum CK18-F could be a clinically useful biomarker to discriminate between NAFL and NASH.
Nonalcoholic fatty liver disease (NAFLD); serum cytokeratin 18 fragment (CK18-F); nonalcoholic fatty liver disease activity score (NAS); nonalcoholic fatty liver (NAFL); definite nonalcoholic steatohepatitis (NASH)
Using 5 fetuses of gestational age (GA) of 15-16 weeks and 4 of GA of 22–25 weeks, we examined site- and stage-dependent differences in CD68-positive microglial cell distribution in human fetal brains. CD68 positive cells were evident in the floor of the fourth ventricle and the pons and olive at 15-16 weeks, accumulating in and around the hippocampus at 22–25 weeks. At both stages, the accumulation of these cells was evident around the optic tract and the anterior limb of the internal capsule. When we compared CD68-positive cell distribution with the topographical anatomy of GAP43-positive developing axons, we found that positive axons were usually unaccompanied by CD68-positive cells, except in the transpontine corticofugal tract and the anterior limb of the internal capsule. Likewise, microglial cell distribution did not correspond with habenulointerpeduncular tract. Therefore, the distribution of CD68-positive cells during normal brain development may not reflect a supportive role of these microglia in axonogenesis of midterm human fetuses.
Phosphorylation of Xenopus Slingshot phosphatase (XSSH) at multiple sites within the tail domain occurs just after germinal vesicle breakdown (GVBD) and is accompanied by dephosphorylation of ADF/cofilin (XAC). Injection of anti-XSSH antibody, which blocks full phosphorylation of XSSH after GVBD, inhibits meiotic spindle formation and XAC dephosphorylation.
We identify Xenopus ADF/cofilin (XAC) and its activator, Slingshot phosphatase (XSSH), as key regulators of actin dynamics essential for spindle microtubule assembly during Xenopus oocyte maturation. Phosphorylation of XSSH at multiple sites within the tail domain occurs just after germinal vesicle breakdown (GVBD) and is accompanied by dephosphorylation of XAC, which was mostly phosphorylated in immature oocytes. This XAC dephosphorylation after GVBD is completely suppressed by latrunculin B, an actin monomer–sequestering drug. On the other hand, jasplakinolide, an F-actin–stabilizing drug, induces dephosphorylation of XAC. Effects of latrunculin B and jasplakinolide are reconstituted in cytostatic factor–arrested extracts (CSF extracts), and XAC dephosphorylation is abolished by depletion of XSSH from CSF extracts, suggesting that XSSH functions as an actin filament sensor to facilitate actin filament dynamics via XAC activation. Injection of anti-XSSH antibody, which blocks full phosphorylation of XSSH after GVBD, inhibits both meiotic spindle formation and XAC dephosphorylation. Coinjection of constitutively active XAC with the antibody suppresses this phenotype. Treatment of oocytes with jasplakinolide also impairs spindle formation. These results strongly suggest that elevation of actin dynamics by XAC activation through XSSH phosphorylation is required for meiotic spindle assembly in Xenopus laevis.
AIM: To investigate the role of functional genetic polymorphisms of metabolic enzymes of tobacco carcinogens in the development of colorectal adenomas.
METHODS: The study subjects were 455 patients with colorectal adenomas and 1052 controls with no polyps who underwent total colonoscopy in a preretirement health examination at two Self Defense Forces hospitals. The genetic polymorphisms studied were CYP1A1*2A (rs 4646903), CYP1A1*2C (rs 1048943), GSTM1 (null or non-null genotype), GSTT1 (null or non-null genotype) and NQO1 C609T (rs 1800566). Genotypes were determined by the polymerase chain reaction (PCR)-restriction fragment length polymorphism or PCR method using genomic DNA extracted from the buffy coat. Cigarette smoking and other lifestyle factors were ascertained by a self-administered questionnaire. The associations of the polymorphisms with colorectal adenomas were examined by means of OR and 95%CI, which were derived from logistic regression analysis. Statistical adjustment was made for smoking, alcohol use, body mass index and other factors. The gene-gene interaction and effect modification of smoking were evaluated by the likelihood ratio test.
RESULTS: None of the five polymorphisms showed a significant association with colorectal adenomas, nor was the combination of GSTM1 and GSTT1. A borderline significant interaction was observed for the combination of CYP1A1*2C and NQO1 (P = 0.051). The OR associated with CYP1A1*2C was significantly lower than unity among individuals with the NQO1 609CC genotype. The adjusted OR for the combination of the CYP1A1*2C allele and NQO1 609CC genotype was 0.61 (95%CI: 0.42-0.91). Although the interaction was not statistically significant (P = 0.24), the OR for individuals carrying the CYP1A1*2C allele and GSTT1 null genotype decreased significantly compared with those who had neither CYP1A1*2C allele nor GSTT1 null genotype (adjusted OR: 0.69, 95%CI: 0.49-0.97). Smoking did not modify the associations of the individual polymorphisms with colorectal adenomas. There was no measurable effect modification of smoking even regarding the combination of the genetic polymorphisms of the phase I and phase II enzymes.
CONCLUSION: Combination of the CYP1A1*2C and NQO1 609CC genotypes was associated with a decreased risk of colorectal adenomas regardless of smoking status.
Colorectal adenoma; Smoking; Polymorphism; CYP1A1; GSTM1; GSTT1; NQO1
The synthesis of 4’-ethynyl-2’-deoxy-4’-thioribonucleosides was carried out utilizing an electrophilic glycosidation in which 4-ethynyl-4-thiofuranoid glycal 16 served as a glycosyl donor. Electrophilic glycosidation between 16 and the silylated nucleobases (N4-acetylcytosine, N6-benzoyladenine and N2-acetyl-O6-diphenylcarbamoylguanine) was carried out in the presence of N-iodosuccinimide (NIS) leading to the exclusive formation of the desired β-anomers 29, 33 and 36. Anti-HIV studies demonstrated that these 4’-thio nucleosides were less cytotoxic to T-lymphocyte (i.e. MT-4 cells) than the corresponding 4’-ethynyl derivatives of 2’-deoxycytidine (44), 2’-deoxyadenosine (45) and 2’-deoxyguanosine (46). Comparison of the selectivity indices (SI) was made between 4’-thionucleosides (32, 41 and 43) and the corresponding 4’-oxygen analogues 44–46 by using the reported CC50 and EC50 values. In the case of cytosine and adenine nucleosides, comparable SI values were obtained: 32 (545) and 45 (458); 41 (>230) and 45 (1,630). In contrast, 4’-ethynyl-2’-deoxy-4’-thioguanosine 43 was found to possess a SI value of >18,200, which is twenty times better than that of 46 (933).
4’-thionucleosides; glycal; electrophilic glycosidation; anti-HIV-1 activity; nucleoside reverse transcriptase inhibitors
Abnormal serum lipid profiles have been noted in patients with chronic hepatitis C virus (HCV) infection. Moreover, many reports suggest that serum lipoprotein profiles are more profoundly distorted in patients with HCV G1b infection who have an unfavorable response to pegylated interferon (peg-IFN) plus ribavirin (RBV) combination therapy. However, after the discovery of single nucleotide polymorphisms near the IL28B gene (rs8099917 and rs12979860) as potent predictive factors affecting the response to peg-IFN plus RBV, lipid factors are thought to be confounding factors.
To re-examine the significance of lipoprotein profiles on virological response to peg-IFN plus RBV combination therapy in patients with chronic HCV G1b infection, we examined cholesterol and triglyceride concentrations in each lipoprotein fraction separated by high performance liquid chromatography.
Patients and Methods
Lipoprotein profiles were examined using fasting sera from 108 patients infected with HCV G1b who had chronic hepatitis, as determined by liver biopsy. Results of lipoprotein profiles and clinical data, including IL28B genotype and amino acid substitution at aa70 of HCV G1b, were compared between patients with a sustained virological response (SVR) and non-SVR or a non-virological response (NVR) and virological responses other than NVR (non-NVR). In addition, significant predictive factors independently associated with virological response to peg-IFNα-2b plus RBV were determined by logistic regression analysis.
An increased ratio of cholesterol/triglyceride in very low-density lipoprotein (odds ratio (OR) 3.03; 95% confidence interval (CI) 1.01-9.44) along with a major genotype of rs8099917 (OR 9.09; 95% CI 2.94-33.33), were independent predictive factors for SVR. In contrast, lipid factors were not elucidated as independent predictive factors for NVR.
Examination of the fasting lipid profile has clinical importance in predicting the efficacy of peg-IFN-α-2b plus RBV combination therapy for patients with HCV G1b even after the discovery of the IL28 genotype as a potent predictive factor.
Hepatitis C; Ribavirin; Lipoproteins; Lipoproteins VLDL; Chromatography, High Pressure Liquid
It is still unclear whether the longitudinal anal muscles or conjoint longitudinal coats (CLCs) are attached to the vagina, although such an attachment, if present, would appear to make an important contribution to the integrated supportive system of the female pelvic floor.
Materials and Methods
Using immunohistochemistry for smooth muscle actin, we examined semiserial frontal sections of 1) eleven female late-stage fetuses at 28-37 weeks of gestation, 2) two female middle-stage fetus (2 specimens at 13 weeks), and, 3) six male fetuses at 12 and 37 weeks as a comparison of the morphology.
In late-stage female fetuses, the CLCs consistently (11/11) extended into the subcutaneous tissue along the vaginal vestibule on the anterior side of the external anal sphincter. Lateral to the CLCs, the external anal sphincter also extended anteriorly toward the vaginal side walls. The anterior part of the CLCs originated from the perimysium of the levator ani muscle without any contribution of the rectal longitudinal muscle layer. However, in 2 female middle-stage fetuses, smooth muscles along the vestibulum extended superiorly toward the levetor ani sling. In male fetuses, the CLCs were separated from another subcutaneous smooth muscle along the scrotal raphe (posterior parts of the dartos layer) by fatty tissue.
In terms of topographical anatomy, the female anterior CLCs are likely to correspond to the lateral extension of the perineal body (a bulky subcutaneous smooth muscle mass present in adult women), supporting the vaginal vestibule by transmission of force from the levator ani.
Anal canal; levator ani muscle; longitudinal anal muscle; rectum; smooth muscle; embryology
We examined a series of changes that occur in the trabecular meshwork fibers of human eyes during fetal development at 12-30 weeks of gestation. At 12 and 15 weeks, the uveal meshwork was stained black with silver impregnation (indicating the predominance of collagen types III and IV) in the endomysium of the ciliary muscle. At 20 weeks, in combination with Schlemm's canal, a dense fibrous tissue mass corresponding to the trabecular meshwork anlage appeared and was colored black. The anlage was continuous with the corneal endothelium rather than with the ciliary muscle. Until 25 weeks, the trabecular meshwork was identifiable as fragmented fiber bundles that stained red-black, suggesting a mixture of collagen types I, III, and IV. At 30 weeks, half of the ciliary muscle fibers were inserted into the scleral spur and not into the meshwork. Therefore, any contribution of ciliary muscle contraction to the differentiation of the trabecular meshwork would appear to be limited. We hypothesize that an uneven distribution of mechanical stresses in the area of the cornea-sclera junction causes a tear thereby creating Schlemm's canal and is accompanied by a change in the collagen fiber types comprising the meshwork.
Trabecular meshwork; Schlemm's canal; Collagen; Silver staining
AIM: To identify factors associated with prognosis of hepatocellular carcinoma (HCC) after initial therapy.
METHODS: A total of 377 HCC patients who were newly treated at Katsushika Medical Center, Japan from January 2000 to December 2009 and followed up for > 2 years, or died during follow-up, were enrolled. The factors related to survival were first analyzed in 377 patients with HCC tumor stage T1-T4 using multivariate Cox proportional hazards regression analysis. A similar analysis was performed in 282 patients with tumor stage T1-T3. Additionally, factors associated with the period between initial and subsequent therapy were examined in 144 patients who did not show local recurrence. Finally, 214 HCC stage T1-T3 patients who died during the observation period were classified into four groups according to their alcohol consumption and postprandial glucose levels, and differences in their causes of death were examined.
RESULTS: On multivariate Cox proportional hazards regression analysis, the following were significantly associated with survival: underlying liver disease stage [non-cirrhosis/Child-Pugh A vs B/C, hazard ratio (HR): 0.603, 95% CI: 0.417-0.874, P = 0.0079], HCC stage (T1/T2 vs T3/T4, HR: 0.447, 95% CI: 0.347-0.576, P < 0.0001), and mean postprandial plasma glucose after initial therapy (< 200 vs ≥ 200 mg/dL, HR: 0.181, 95% CI: 0.067-0.488, P = 0.0008). In T1-T3 patients, uninterrupted alcohol consumption after initial therapy (no vs yes, HR: 0.641, 95% CI: 0.469-0.877, P = 0.0055) was significant in addition to underlying liver disease stage (non-cirrhosis/Child-Pugh A vs B/C, HR: 0649, 95% CI: 0.476-0.885, P = 0.0068), HCC stage (T1 vs T2/T3, HR: 0.788, 95% CI: 0.653-0.945, P = 0.0108), and mean postprandial plasma glucose after initial therapy (< 200 mg/dL vs ≥ 200 mg/dL, HR: 0.502, 95% CI: 0.337-0.747, P = 0.0005). In patients without local recurrence, time from initial to subsequent therapy for newly emerging HCC was significantly longer in the “postprandial glucose within 200 mg/dL group” than the “postprandial glucose > 200 mg/dL group” (log-rank test, P < 0.05), whereas there was no difference in the period between the “non-alcohol group” (patients who did not drink regularly or those who could reduce their daily consumption to < 20 g) and the “continuation group” (drinkers who continued to drink > 20 g daily). Of 214 T1-T3 patients who died during the observation period, death caused by other than HCC progression was significantly more frequent in “group AL” (patients in the continuation and postprandial glucose within 200 mg/dL groups) than “group N” (patients in the non-alcohol and postprandial glucose within 200 mg/dL groups) (P = 0.0016).
CONCLUSION: This study found that abstinence from habitual alcohol consumption and intensive care for diabetes mellitus were related to improved prognosis in HCC patients.
Hepatocellular carcinoma; Prognosis; Alcohol consumption; Diabetes mellitus; Postprandial plasma glucose level; Initial therapy; Local recurrence; Survival
Behavioral changes driven by reinforcement and punishment are referred to as simple or model-free reinforcement learning. Animals can also change their behaviors by observing events that are neither appetitive nor aversive, when these events provide new information about payoffs available from alternative actions. This is an example of model-based reinforcement learning, and can be accomplished by incorporating hypothetical reward signals into the value functions for specific actions. Recent neuroimaging and single-neuron recording studies showed that the prefrontal cortex and the striatum are involved not only in reinforcement and punishment, but also in model-based reinforcement learning. We found evidence for both types of learning, and hence hybrid learning, in monkeys during simulated competitive games. In addition, in both the dorsolateral prefrontal cortex and orbitofrontal cortex, individual neurons heterogeneously encoded signals related to actual and hypothetical outcomes from specific actions, suggesting that both areas might contribute to hybrid learning.
belief learning; decision making; game theory; reinforcement learning; reward
AIM: To construct formulae for predicting the likelihood of ribavirin-induced anemia in pegylated interferon α plus ribavirin for chronic hepatitis C.
METHODS: Five hundred and sixty-one Japanese patients with hepatitis C virus genotype 1b who had received combination treatment were enrolled and assigned randomly to the derivation and confirmatory groups. Single nucleotide polymorphisms at or nearby ITPA were genotyped by real-time detection polymerase chain reaction. Factors influencing significant anemia (hemoglobin concentration < 10.0 g/dL at week 4 of treatment) and significant hemoglobin decline (declining concentrations > 3.0 g/dL at week 4) were analyzed using multiple regression analyses. Prediction formulae were constructed by significantly independent factors.
RESULTS: Multivariate analysis for the derivation group identified four independent factors associated with significant hemoglobin decline: hemoglobin decline at week 2 [P = 3.29 × 10-17, odds ratio (OR) = 7.54 (g/dL)], estimated glomerular filtration rate [P = 2.16 × 10-4, OR = 0.962 (mL/min/1.73 m2)], rs1127354 (P = 5.75 × 10-4, OR = 10.94) and baseline hemoglobin [P = 7.86 × 10-4, OR = 1.50 (g/dL)]. Using the model constructed by these factors, positive and negative predictive values and predictive accuracy were 79.8%, 88.8% and 86.2%, respectively. For the confirmatory group, they were 83.3%, 91.0% and 88.3%. These factors were closely correlated with significant anemia. However, the model could not be constructed, because no patients with rs1127354 minor genotype CA/AA had significant anemia.
CONCLUSION: Reliable formulae for predicting the likelihood of ribavirin-induced anemia were constructed. Such modeling may be useful in developing individual tailoring and optimization of ribavirin dosage.
Chronic hepatitis C virus infection; Ribavirin; Pegylated interferon α; Prediction model; Hemolytic anemia; Single nucleotide polymorphism
Recombinant human gelatins with defined molecular weights were modified with cholesterol to make them amphiphilic in nature. We investigated the feasibility of these modified human gelatins acting as a carrier of antigenic proteins for inducing cellular immunity. The aim of this study was to synthesize novel and effective compounds for vaccine delivery in vivo.
Two types of cholesterol-modified gelatin micelles, anionic cholesterol-modified gelatin (aCMG) and cationic-cholesterol modified gelatin (cCMG), were synthesized using different cholesterol derivatives such as the cholesterol-isocyanate (Ch-I) for aCMG and amino-modified cholesterol for cCMG. One was anionic and the other cationic, and therefore they differed in terms of their zeta potential. The aCMG and cCMG were characterized for their size, zeta potential, and in their ability to form micelles. Cytotoxicity was also evaluated. The modified human gelatins were then investigated as a carrier of antigenic proteins for inducing cellular immunity both in vitro in DC 2.4 cells, a murine dendritic cell line, as well as in vivo. The mechanism of entry of the polymeric micelles into the cells was also evaluated.
It was found that only cCMG successfully complexed with the model antigenic protein, fluorescein-isothiocyanate ovalbumin (OVA) and efficiently delivered and processed proteins in DC 2.4 cells. It was hypothesized that cCMG enter the cells predominantly by a caveolae-mediated pathway that required tyrosine kinase receptors on the cell surface. Animal testing using mice showed that the cationic cholesterol-modified gelatin complexed with OVA produced significantly high antibody titers against OVA: 2580-fold higher than in mice immunized with free OVA.
Conclusively, cCMG has shown to be very effective in stimulating an immune response due to its high efficiency, stability, and negligible cytotoxicity.
recombinant human gelatin; cholesterol; micelle; protein delivery; caveolae pathway; receptor-mediated endocytosis
The synthesis of 4′-ethynyl-2′-deoxy-4′-thioribonucleosides was carried out utilizing an electrophilic glycosidation in which 4-ethynyl-4-thiofuranoid glycal 16 served as a glycosyl donor. Electrophilic glycosidation between 16 and the silylated nucleobases (N4-acetylcytosine, N6-benzoyladenine, and N2-acetyl-O6-diphenylcarbamoylguanine) was carried out in the presence of N-iodosuccinimide (NIS), leading to the exclusive formation of the desired β-anomers 29, 33, and 36. Anti-HIV studies demonstrated that these 4′-thio nucleosides were less cytotoxic to T-lymphocyte (i.e., MT-4 cells) than the corresponding 4′-ethynyl derivatives of 2′-deoxycytidine (44), 2′-deoxyadenosine (45), and 2′-deoxyguanosine (46). Comparison of the selectivity indices (SI) was made between 4′-thionucleosides (32, 41, and 43) and the corresponding 4′-oxygen analogues 44-46 by using the reported CC50 and EC50 values. In the case of cytosine and adenine nucleosides, comparable SI values were obtained as follows: 32 (545) and 44 (458); 41 (>230) and 45 (1630). In contrast, 4′-ethynyl-2′-deoxy-4′-thioguanosine 43 was found to possess a SI value of >18200, which is 20 times better than that of 46 (933).
4′-Thionucleosides; glycal; electrophilic glycosidation; anti-HIV-1 activity; nucleoside reverse transcriptase inhibitors
We recently demonstrated the morphology of the anococcygeal ligament. As the anococcygeal ligament and raphe are often confused, the concept of the anococcygeal raphe needs to be re-examined from the perspective of fetal development, as well as in terms of adult morphology.
Materials and Methods
We examined the horizontal sections of 15 fetuses as well as adult histology. From cadavers, we obtained an almost cubic tissue mass containing the dorsal wall of the anorectum, the coccyx and the covering skin. Most sections were stained with hematoxylin and eosin or Masson-trichrome solution.
The adult ligament contained both smooth and striated muscle fibers. A similar band-like structure was seen in fetuses, containing: 1) smooth muscle fibers originating from the longitudinal muscle coat of the anal canal and 2) striated muscle fibers from the external anal sphincter (EAS). However, in fetuses, the levator ani muscle did not attach to either the band or the coccyx. Along and around the anococcygeal ligament, we did not find any aponeurotic tissue with transversely oriented fibers connecting bilateral levator ani slings. Instead, in adults, a fibrous tissue mass was located at a gap between bilateral levator ani slings; this site corresponded to the dorsal side of the ligament and the EAS in the immediately deep side of the natal skin cleft.
We hypothesize that a classically described raphe corresponds to the specific subcutaneous tissue on the superficial or dorsal side of the anococcygeal ligament.
Anal canal; rectum; smooth muscle; embryology; anatomy; histology
Knowledge about hypothetical outcomes from unchosen actions is beneficial only when such outcomes can be correctly attributed to specific actions. Here, we show that during a simulated rock-paper-scissors game, rhesus monkeys can adjust their choice behaviors according to both actual and hypothetical outcomes from their chosen and unchosen actions, respectively. In addition, neurons in both dorsolateral prefrontal cortex and orbitofrontal cortex encoded the signals related to actual and hypothetical outcomes immediately after they were revealed to the animal. Moreover, compared to the neurons in the orbitofrontal cortex, those in the dorsolateral prefrontal cortex were more likely to change their activity according to the hypothetical outcomes from specific actions. Conjunctive and parallel coding of multiple actions and their outcomes in the prefrontal cortex might enhance the efficiency of reinforcement learning and also contribute to their context-dependent memory.
Arabidopsis belongs to the Brassicaceae family and plays an important role as a model plant for which researchers have developed fine-tuned genome resources. Genome sequencing projects have been initiated for other members of the Brassicaceae family. Among these projects, research on Chinese cabbage (Brassica rapa subsp. pekinensis) started early because of strong interest in this species. Here, we report the development of a library of Chinese cabbage full-length cDNA clones, the RIKEN BRC B. rapa full-length cDNA (BBRAF) resource, to accelerate research on Brassica species. We sequenced 10 000 BBRAF clones and confirmed 5476 independent clones. Most of these cDNAs showed high homology to Arabidopsis genes, but we also obtained more than 200 cDNA clones that lacked any sequence homology to Arabidopsis genes. We also successfully identified several possible candidate marker genes for plant defence responses from our analysis of the expression of the Brassica counterparts of Arabidopsis marker genes in response to salicylic acid and jasmonic acid. We compared gene expression of these markers in several Chinese cabbage cultivars. Our BBRAF cDNA resource will be publicly available from the RIKEN Bioresource Center and will help researchers to transfer Arabidopsis-related knowledge to Brassica crops.
Arabidopsis; Brassica rapa; full-length cDNA; jasmonic acid; salicylic acid
The western flower thrips (Frankliniella occidentalis [Pergande]) is one of the most important insect herbivores of cultivated plants. However, no pesticide provides complete control of this species, and insecticide resistance has emerged around the world. We previously reported the important role of jasmonate (JA) in the plant's immediate response to thrips feeding by using an Arabidopsis leaf disc system. In this study, as the first step toward practical use of JA in thrips control, we analyzed the effect of JA-regulated Arabidopsis defense at the whole plant level on thrips behavior and life cycle at the population level over an extended period. We also studied the effectiveness of JA-regulated plant defense on thrips damage in Chinese cabbage (Brassica rapa subsp. pekinensis).
Thrips oviposited more on Arabidopsis JA-insensitive coi1-1 mutants than on WT plants, and the population density of the following thrips generation increased on coi1-1 mutants. Moreover, thrips preferred coi1-1 mutants more than WT plants. Application of JA to WT plants before thrips attack decreased the thrips population. To analyze these important functions of JA in a brassica crop plant, we analyzed the expression of marker genes for JA response in B. rapa. Thrips feeding induced expression of these marker genes and significantly increased the JA content in B. rapa. Application of JA to B. rapa enhanced plant resistance to thrips, restricted oviposition, and reduced the population density of the following generation.
Our results indicate that the JA-regulated plant defense restricts thrips performance and preference, and plays an important role in the resistance of Arabidopsis and B. rapa to thrips damage.
Visceral obesity is positively related to insulin resistance. The nature of the relationship between waist circumference and insulin resistance has not been known in Japanese populations. This study examined the relationship between waist circumference and insulin resistance and evaluated the optimal cutoff point for waist circumference in relation to insulin resistance in middle-aged Japanese men.
Study subjects included 4800 Japanese men aged 39 to 60 years. Insulin resistance was evaluated by the homeostasis model assessment of insulin resistance (HOMA-IR). The relationship of waist circumference with HOMA-IR was assessed by use of adjusted means of HOMA-IR and odds ratios of elevated HOMA-IR defined as the highest quintile (≥2.00). Receiver operating characteristics (ROC) curve analysis using Youden index and the area under curve (AUC) was employed to determine optimal cutoffs of waist circumference in relation to HOMA-IR.
Adjusted geometric means of HOMA-IR and prevalence odds of elevated HOMA-IR were progressively higher with increasing levels of waist circumference. In the ROC curve analysis, the highest value of Youden index was obtained for a cutoff point of 85 cm in waist circumference across different values of HOMA-IR. Multiple logistic regression analysis also indicated that the AUC was consistently the largest for a waist circumference of 85 cm.
Waist circumference is linearly related to insulin resistance, and 85 cm in waist circumference is an optimal cutoff in predicting insulin resistance in middle-aged Japanese men.
In the unfolded protein response (UPR) signaling pathway, accumulation of
unfolded proteins in the endoplasmic reticulum (ER) activates a transmembrane
kinase/ribonuclease Ire1, which causes the transcriptional induction of
ER-resident chaperones, including BiP/Kar2. It was previously hypothesized
that BiP/Kar2 plays a direct role in the signaling mechanism. In this model,
association of BiP/Kar2 with Ire1 represses the UPR pathway while under
conditions of ER stress, BiP/Kar2 dissociation leads to activation. To test
this model, we analyzed five temperature-sensitive alleles of the yeast
KAR2 gene. When cells carrying a mutation in the Kar2
substrate-binding domain were incubated at the restrictive temperature,
association of Kar2 to Ire1 was disrupted, and the UPR pathway was activated
even in the absence of extrinsic ER stress. Conversely, cells carrying a
mutation in the Kar2 ATPase domain, in which Kar2 poorly dissociated from Ire1
even in the presence of tunicamycin, a potent inducer of ER stress, were
unable to activate the pathway. Our findings provide strong evidence in
support of BiP/Kar2-dependent Ire1 regulation model and suggest that Ire1
associates with Kar2 as a chaperone substrate. We speculate that recognition
of unfolded proteins is based on their competition with Ire1 for binding with
In contrast to the slow rate of depolymerization of pure actin in vitro, populations of actin filaments in vivo turn over rapidly. Therefore, the rate of actin depolymerization must be accelerated by one or more factors in the cell. Since the actin dynamics in Listeria monocytogenes tails bear many similarities to those in the lamellipodia of moving cells, we have used Listeria as a model system to isolate factors required for regulating the rapid actin filament turnover involved in cell migration. Using a cell-free Xenopus egg extract system to reproduce the Listeria movement seen in a cell, we depleted candidate depolymerizing proteins and analyzed the effect that their removal had on the morphology of Listeria tails. Immunodepletion of Xenopus actin depolymerizing factor (ADF)/cofilin (XAC) from Xenopus egg extracts resulted in Listeria tails that were approximately five times longer than the tails from undepleted extracts. Depletion of XAC did not affect the tail assembly rate, suggesting that the increased tail length was caused by an inhibition of actin filament depolymerization. Immunodepletion of Xenopus gelsolin had no effect on either tail length or assembly rate. Addition of recombinant wild-type XAC or chick ADF protein to XAC-depleted extracts restored the tail length to that of control extracts, while addition of mutant ADF S3E that mimics the phosphorylated, inactive form of ADF did not reduce the tail length. Addition of excess wild-type XAC to Xenopus egg extracts reduced the length of Listeria tails to a limited extent. These observations show that XAC but not gelsolin is essential for depolymerizing actin filaments that rapidly turn over in Xenopus extracts. We also show that while the depolymerizing activities of XAC and Xenopus extract are effective at depolymerizing normal filaments containing ADP, they are unable to completely depolymerize actin filaments containing AMPPNP, a slowly hydrolyzible ATP analog. This observation suggests that the substrate for XAC is the ADP-bound subunit of actin and that the lifetime of a filament is controlled by its nucleotide content.