Anisotropic light-matter coupling and below-threshold excitation dynamics in an organic crystal microcavity.

Organic semiconductors are promising candidates as platforms for room temperature polaritonic devices. An issue for practical implementation of organic polariton devices is the lowering of condensation threshold. Here we investigate anisotropic light-matter coupling characteristics in an organic crystal microcavity showing strong molecular orientation. Furthermore, the below-threshold excitation dynamics are investigated to clarify the spontaneous transition pathways from reservoir to polariton states. Time-resolved photoluminescence measurements reveal that photonic/excitonic hybrid transition processes coexist in the microcavity system. This finding provides valuable insights into a detailed understanding of polariton dynamics and help in the design of polaritonic devices showing a low-threshold condensed phase.

Reactions of difunctional electrophiles with functionalized aryllithium compounds: remarkable chemoselectivity by flash chemistry.

Flash chemistry using flow microreactors enables highly chemoselective reactions of difunctional electrophiles with functionalized aryllithium compounds by virtue of extremely fast micromixing. The approach serves as a powerful method for protecting-group-free synthesis using organolithium compounds and opens a new possibility in the synthesis of polyfunctional organic molecules.

Questionnaire Survey for Inflammatory Bowel Disease Patients in Japan; A Web-Based Japan, Crohn's Disease, Ulcerative Colitis, Patients Survey.

Background/Aims: The prevalence of inflammatory bowel disease (IBD) in Japan has been increasing. We aimed to clarify the symptoms of patients with IBD in Japan using an internet-based questionnaire survey. Methods: Overall, 805 patients with IBD were asked to complete an internet-based questionnaire addressing their history of disturbances in daily activities, prevalence of fecal urgency, incontinence, and treatment preferences. Results: Responses were obtained from 447 patients with IBD (mean age: 54 years; 70% were men), comprising 363 patients with ulcerative colitis (UC), and 84 with Crohn's disease (CD). Notably, 16% of patients with UC and 35% with CD took over 1 year until the diagnosis of IBD, and 5% of patients with CD visited more than 5 medical institutions. Patients with CD were more likely to experience disturbances in their diet, work, travel, and outings than those with UC. Fecal urgency and incontinence were significantly more frequent in patients with CD than in those with UC (72% vs. 44%, and 50% vs. 26%, respectively). In contrast, 26% of the men and 37% of women with IBD had constipation. Acid reflux, sleep disorders, and depressive symptoms were present in approximately 30% of the patients. Oral administration was preferred. Conclusions: Patients with IBD in Japan experience more severe disturbances in their daily activities, and these are more severe in those with CD than those with UC. In addition to fecal urgency and incontinence, care is required for constipation, acid reflux, sleep disorders, and depressive symptoms.

Illumination uniformity of an edge-lit backlight with emission angle control.

Viewing range of a liquid crystal display can be controlled by a liquid crystal device inserted between a light source and a light-guide of an edge-lit backlight unit. Here, we propose an output coupler with a vertical optical window through which light is extracted from a light-guide. Rays with large propagation angles and those with small angles have a comparable probability of hitting this window. As a result, a single set of these output couplers can provide uniform light extraction for both settings of a wide viewing range and a narrow one. Ray tracing simulations confirm these findings.

Pyruvate kinase deletion as an effective phenotype to enhance lysine production in Corynebacterium glutamicum ATCC13032: Redirecting the carbon flow to a precursor metabolite.

Various attempts have been made to enhance lysine production in Corynebacterium glutamicum. Pyruvate kinase (PYK) defect is one of the strategies used to enhance the supply of oxaloacetic acid (OAA), a precursor metabolite for lysine biosynthesis. However, inconsistent effects of this mutation have been reported: positive effects of PYK defect in mutants having phosphoenolpyruvate carboxylase (PEPC) desensitized to feedback inhibition by aspartic acid, while negative effects in simple PYK gene (pyk) knockout mutants. To address these discrepancies, the effects of pyk deletion on lysine yield were investigated with or without the D299N mutation in ppc rendering PEPC desensitization. C. glutamicum ATCC13032 mutant strain P with a feedback inhibition-desensitized aspartokinase was used as the parent strain, producing 9.36 g/L lysine from 100 g/L glucose in a jar fermentor culture. Under these conditions, while the simple mutant D2 with pyk deletion or R2 with the PEPC-desensitization mutation showed marginally increased lysine yield (∼1.1-fold, not significant), the mutant DR2 strain having both mutations showed synergistically increased lysine productivity (1.38-fold, 12.9 g/L). Therefore, the pyk deletion is effective under a PEPC-desensitized background, which ensures enhanced supply of OAA, thus clarifying the discrepancies. A citrate synthase defective mutation (S252C in gltA) further increased the lysine yield in strain DR2 (1.68-fold, 15.7 g/L). Thus, these three mutations coordinately enhanced the lysine yield. Both the malate:quinone oxidoreductase activity and respiration rate were significantly reduced in strains D2 and DR2. Overall, these results provide valuable knowledge for engineering the anaplerotic reaction to increase lysine yield in C. glutamicum.

Effect of pyruvate kinase gene deletion on the physiology of Corynebacterium glutamicum ATCC13032 under biotin-sufficient non-glutamate-producing conditions: Enhanced biomass production.

The effect of pyruvate kinase gene (pyk) deletion on the physiology of Corynebacterium glutamicum ATCC13032 was investigated under biotin-sufficient, non-glutamate-producing conditions. In a complex medium containing 100 g/L glucose, a defined pyk deletion mutant, strain D1, exhibited 35% enhancement in glucose consumption rate, 37% increased growth and a 57% reduction in respiration rate compared to the wild-type parent. Significant upregulation of phosphoenolpyruvate (PEP) carboxylase and downregulation of PEP carboxykinase activities were observed in the D1 mutant, which may have prevented over-accumulation of PEP caused by the pyk deletion. Moreover, we found a dramatic 63% reduction in the activity of malate:quinone oxidoreductase (MQO) in the D1 mutant. MQO, a TCA cycle enzyme that converts malate to oxaloacetate (OAA), constitutes a major primary gate to the respiratory chain in C. glutamicum, thus explaining the reduced respiration rate in the mutant. Additionally, pyruvate carboxylase gene expression was downregulated in the mutant. These changes seemed to prevent OAA over-accumulation caused by the activity changes of PEP carboxylase/PEP carboxykinase. Intrinsically the same alterations were observed in the cultures conducted in a minimal medium containing 20 g/L glucose. Despite these responses in the mutant, metabolic distortion caused by pyk deletion under non-glutamate-producing conditions required amelioration by increased biomass production, as metabolome analysis revealed increased intracellular concentrations of several precursor metabolites for building block formation associated with pyk deletion. These fermentation profiles and metabolic alterations observed in the mutant reverted completely to the wild-type phenotypes in the pyk-complemented strain, suggesting the observed metabolic changes were caused by the pyk deletion. These results demonstrated multilateral strategies to overcome metabolic disturbance caused by pyk deletion in this bacterium.

Mechanism of increased respiration in an H+-ATPase-defective mutant of Corynebacterium glutamicum.

We previously reported that a spontaneous H(+)-ATPase-defective mutant of Corynebacterium glutamicum, F172-8, derived from C. glutamicum ATCC 14067, showed enhanced glucose consumption and respiration rates. To investigate the genome-based mechanism of enhanced respiration rate in such C. glutamicum mutants, A-1, an H(+)-ATPase-defective mutant derived from C. glutamicum ATCC 13032, which harbors the same point mutation as F172-8, was used in this study. A-1 showed similar fermentation profiles to F172-8 when cultured in a jar fermentor. Enzyme activity measurements, quantitative real-time PCR, and DNA microarray analysis suggested that A-1 enhanced malate:quinone oxidoreductase/malate dehydrogenase and l-lactate dehydrogenase/NAD(+)-dependent-lactate dehydrogenase coupling reactions, but not NADH dehydrogenase-II, for reoxidation of the excess NADH arising from enhanced glucose consumption. A-1 also up-regulated succinate dehydrogenase, which may result in the relief of excess proton-motive force (pmf) in the H(+)-ATPase mutant. In addition, the transcriptional level of cytochrome bd oxidase, but not cytochrome bc(1)-aa(3), also increased, which may help prevent the excess pmf generation caused by enhanced respiration. These results indicate that C. glutamicum possesses intriguing strategies for coping with NADH over-accumulation. Furthermore, these mechanisms are different from those in Escherichia coli, even though the two species use similar strategies to prevent excess pmf generation.

Peculiar protein-protein interactions of the novel endoplasmic reticulum membrane protein Rcr1 and ubiquitin ligase Rsp5.

Overproduction of the ER membrane protein Rcr1 makes Saccharomyces cerevisiae resistant to Congo red by reducing the chitin content through a unknown mechanism. By both co-immunoprecipitation and yeast two-hybrid experiments, specific interaction between Rcr1 and the ubiquitin ligase Rsp5 was found. This binding was largely mediated by a singular VPEY sequence in Rcr1 in addition to PPSY, the consensus ligand motif of the WW domains. Mutant analysis indicated that Rsp5 and other Rcr1-interacting proteins discovered in the current screen were not engaged in Congo red resistance.

A novel endoplasmic reticulum membrane protein Rcr1 regulates chitin deposition in the cell wall of Saccharomyces cerevisiae.

Congo red binds to the cell wall and inhibits the growth of yeast. In a screening for multicopy suppressor genes of Congo red hypersensitivity of erd1Delta mutant, we found that a previously uncharacterized gene, YBR005w, makes most of the Saccharomyces cerevisiae strains resistant to Congo red. This gene was named RCR1 (resistance to Congo red 1). An rcr1Delta null mutant showed an increased sensitivity to Congo red. RCR1 encodes a novel ER membrane protein with a single transmembrane domain. Molecular dissection suggested that the transmembrane domain and a part of the C-terminal polypeptide are sufficient for the activity. We examined the effect of RCR1 in various null mutants of genes related to the cell wall. The resistance of mutants to Congo red correlates with a reduction of chitin content. Multicopy RCR1 caused a significant decrease in the chitin content while the amount of alkali-soluble glucan did not change. The binding of Calcofluor white to the cell wall significantly decreased in these cells. Our results show that RCR1 regulates the chitin deposition and add firm genetic and biochemical evidences that the primary target of Congo red is chitin in S. cerevisiae.

A Rho GDP-dissociation inhibitor is involved in cytokinesis of Dictyostelium.

Homology searches toward the EST databases of Dictyostelium discoideum identified two putative Rho GDP-dissociation inhibitors (RhoGDIs), RhoGDI1 and RhoGDI2. In this study, the roles of RhoGDI1 in cytokinesis were examined. The RhoGDI1-null Dictyostelium strains produced by homologous recombination were viable but generated multinucleate giant cells in suspension culture, suggesting that RhoGDI1 is involved in cytokinesis. The expression of green fluorescent protein (GFP)-tagged RhoGDI1 complemented the defects of the RhoGDI1-null cells, and the GFP-RhoGDI1 is predominantly present in cytoplasm of the cell-like yeast RhoGDI. Of 15 Rho family GTPases in Dictyostelium currently known, Dictyostelium versions of Rac1 proteins (Rac1A, Rac1B, and Rac1C) and RacE that are reportedly involved in Dictyostelium cytokinesis, showed two-hybrid interactions with RhoGDI1 as well as human and yeast Cdc42. These results suggest that RhoGDI1 is involved in cytokinesis of Dicytostelium through the regulation of Rho family GTPases Rac1s and/or RacE.