Role of Copper Ions in the Regulation of L-Glutamate Biosynthesis

Cell-free extracts of Brevibacterium thiogenitalis culture grown in the presence of copper catalyzed the oxidation of NADH₂ and succinate through an electron transport chain which contained menaquinones and cytochromes a, b and c. On the other hand, extracts of cells grown in the absence of copper lacked cytochromes a and c, and contained cytochrome d.

These findings, as well as the results obtained in inhibition experiments, suggest that in copper-deficient cells the major part of NADH₂ was oxidized via a bypass in which the electrons were transferred directly from flavoprotein or cytochrome b to molecular oxygen.

Electron transport from these substrates to molecular oxygen resulted in ATP synthesis. The average P/O ratios in extracts of the copper-sufficient cells were 0.33 for generated NADH₂, 0.20 for added NADH₂, and 0.34 for succinate, and those in extracts of the copper-deficient cells were 0.15, 0.13 and 0.21, respectively. In addition, a linear relationship was found between the yield of L-glutamate from acetate and the P/Ο ratios with both NADH₂ and succinate as substrates.

From these results, it is reasonable to consider that the poor yield of L-glutamate from acetate in copper-deficient cells was due to a reduction in energy supply, which was caused by the low efficiency of oxidative phosphorylation.     

Oxygen uptake,heart rate,perceived exertion,and integrated electromyogram of the lower and upper extremities during level and Nordic walking on a treadmill

The purpose of this study was to characterize responses in oxygen uptake ( V·O2), heart rate (HR), perceived exertion (OMNI scale) and integrated electromyogram (iEMG) readings during incremental Nordic walking (NW) and level walking (LW) on a treadmill. Ten healthy adults (four men, six women), who regularly engaged in physical activity in their daily lives, were enrolled in the study. All subjects were familiar with NW. Each subject began walking at 60 m/min for 3 minutes, with incremental increases of 10 m/min every 2 minutes up to 120 m/min V·O2 , V·E and HR were measured every 30 seconds, and the OMNI scale was used during the final 15 seconds of each exercise. EMG readings were recorded from the triceps brachii, vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior muscles. V·O2 was significantly higher during NW than during LW, with the exception of the speed of 70 m/min (P < 0.01). V·E and HR were higher during NW than LW at all walking speeds (P < 0.05 to 0.001). OMNI scale of the upper extremities was significantly higher during NW than during LW at all speeds (P < 0.05). Furthermore, the iEMG reading for the VL was lower during NW than during LW at all walking speeds, while the iEMG reading for the BF and GA muscles were significantly lower during NW than LW at some speeds. These data suggest that the use of poles in NW attenuates muscle activity in the lower extremities during the stance and push-off phases, and decreases that of the lower extremities and increase energy expenditure of the upper body and respiratory system at certain walking speeds.     

Caffeine fostering of mycoparasitic fungi against phytopathogens

Caffeine (1,3,7-trimethixanthine) is a typical purine alkaloid produced in more than 80 plant species. Its biological role is considered to strengthen plant''s defense capabilities, directly as a toxicant to biotic attackers (allelopathy) and indirectly as an activator of defense system (priming). Caffeine is actively secreted into rhizosphere through primary root, and possibly affects the structure of microbe community nearby. The fungal community in coffee plant rhizosphere is enriched with particular species, including Trichoderma family, a mycoparasite that attacks and kills phytopathogens by coiling and destroying their hyphae. In the present study, the caffeine response of 8 filamentous fungi, 4 mycoparasitic Trichoderma, and 4 prey phytopathogens, was examined. Results showed that allelopathic effect of caffeine on fungal growth and development was differential, being stronger on pathogens than on Trichoderma species. Upon confronting, the prey immediately ceased the growth, whereas the predator continued to grow, indicating active mycoparasitism to have occurred. Caffeine enhanced mycoparasitism up to 1.7-fold. Caffeine thus functions in a double-track manner against fungal pathogens: first by direct suppression of growth and development, and second by assisting their natural enemy. These observations suggest that caffeine is a powerful weapon in the arms race between plants and pathogens by fostering enemy''s enemy, and we propose the idea of "caffeine fostering" as the third role of caffeine.     

Environmental DNA as a ‘Snapshot’ of Fish Distribution: A Case Study of Japanese Jack Mackerel in Maizuru Bay,Sea of Japan

Recent studies in streams and ponds have demonstrated that the distribution and biomass of aquatic organisms can be estimated by detection and quantification of environmental DNA (eDNA). In more open systems such as seas, it is not evident whether eDNA can represent the distribution and biomass of aquatic organisms because various environmental factors (e.g., water flow) are expected to affect eDNA distribution and concentration. To test the relationships between the distribution of fish and eDNA, we conducted a grid survey in Maizuru Bay, Sea of Japan, and sampled surface and bottom waters while monitoring biomass of the Japanese jack mackerel (Trachurus japonicus) using echo sounder technology. A linear model showed a high R² value (0.665) without outlier data points, and the association between estimated eDNA concentrations from the surface water samples and echo intensity was significantly positive, suggesting that the estimated spatial variation in eDNA concentration can reflect the local biomass of the jack mackerel. We also found that a best-fit model included echo intensity obtained within 10–150 m from water sampling sites, indicating that the estimated eDNA concentration most likely reflects fish biomass within 150 m in the bay. Although eDNA from a wholesale fish market partially affected eDNA concentration, we conclude that eDNA generally provides a ‘snapshot’ of fish distribution and biomass in a large area. Further studies in which dynamics of eDNA under field conditions (e.g., patterns of release, degradation, and diffusion of eDNA) are taken into account will provide a better estimate of fish distribution and biomass based on eDNA.     

Clinical Course and Changes in High-Resolution Computed Tomography Findings in Patients with Idiopathic Pulmonary Fibrosis without Honeycombing

Some patients with idiopathic pulmonary fibrosis (IPF) do not have honeycombing on high-resolution computed tomography (HRCT) at their initial evaluation. The clinical course and sequential changes in HRCT findings in these patients are not fully understood. We reviewed the cases of 43 patients with IPF without honeycombing on initial HRCT from institutions throughout Japan. All patients were diagnosed with IPF based on a surgical lung biopsy. Multidisciplinary discussions were held five times between 2011 and 2014, to exclude alternative etiologies. We evaluated the sequential changes in HRCT findings in 30 patients with IPF. We classified these 30 patients into three groups based on their HRCT patterns and clarified the clinical characteristics and prognosis among the groups. The patterns of all 30 patients on initial HRCT corresponded to a possible usual interstitial pneumonia (UIP) pattern which was described in the 2011 International Statement. On long-term follow-up (71.0±38.7 standard deviation [SD] months), honeycombing was seen in 16 patients (53%, the HoneyCo group); traction bronchiectasis or cysts without honeycombing was observed in 12 patients (40%, the NoHoneyCo group), and two patients showed no interval change (7%, the NoChange group) on HRCT. The mean survival periods of the HoneyCo and NoHoneyCo groups were 67.1 and 61.2 months, respectively (p = 0.76). There are some patients with IPF whose conditions chronically progress without honeycombing on HRCT. The appearance of honeycombing on HRCT during the follow-up might not be related to prognosis.     

Individual Colorimetric Observer Model

This study proposes a vision model for individual colorimetric observers. The proposed model can be beneficial in many color-critical applications such as color grading and soft proofing to assess ranges of color matches instead of a single average match. We extended the CIE 2006 physiological observer by adding eight additional physiological parameters to model individual color-normal observers. These eight parameters control lens pigment density, macular pigment density, optical densities of L-, M-, and S-cone photopigments, and λ_max shifts of L-, M-, and S-cone photopigments. By identifying the variability of each physiological parameter, the model can simulate color matching functions among color-normal populations using Monte Carlo simulation. The variabilities of the eight parameters were identified through two steps. In the first step, extensive reviews of past studies were performed for each of the eight physiological parameters. In the second step, the obtained variabilities were scaled to fit a color matching dataset. The model was validated using three different datasets: traditional color matching, applied color matching, and Rayleigh matches.     

Functional and Structural Analysis of a β-Glucosidase Involved in β-1,2-Glucan Metabolism in Listeria innocua

Despite the presence of β-1,2-glucan in nature, few β-1,2-glucan degrading enzymes have been reported to date. Recently, the Lin1839 protein from Listeria innocua was identified as a 1,2-β-oligoglucan phosphorylase. Since the adjacent lin1840 gene in the gene cluster encodes a putative glycoside hydrolase family 3 β-glucosidase, we hypothesized that Lin1840 is also involved in β-1,2-glucan dissimilation. Here we report the functional and structural analysis of Lin1840. A recombinant Lin1840 protein (Lin1840r) showed the highest hydrolytic activity toward sophorose (Glc-β-1,2-Glc) among β-1,2-glucooligosaccharides, suggesting that Lin1840 is a β-glucosidase involved in sophorose degradation. The enzyme also rapidly hydrolyzed laminaribiose (β-1,3), but not cellobiose (β-1,4) or gentiobiose (β-1,6) among β-linked gluco-disaccharides. We determined the crystal structures of Lin1840r in complexes with sophorose and laminaribiose as productive binding forms. In these structures, Arg572 forms many hydrogen bonds with sophorose and laminaribiose at subsite +1, which seems to be a key factor for substrate selectivity. The opposite side of subsite +1 from Arg572 is connected to a large empty space appearing to be subsite +2 for the binding of sophorotriose (Glc-β-1,2-Glc-β-1,2-Glc) in spite of the higher K_m value for sophorotriose than that for sophorose. The conformations of sophorose and laminaribiose are almost the same on the Arg572 side but differ on the subsite +2 side that provides no interaction with a substrate. Therefore, Lin1840r is unable to distinguish between sophorose and laminaribiose as substrates. These results provide the first mechanistic insights into β-1,2-glucooligosaccharide recognition by β-glucosidase.     

Glycosylation Status of CD43 Protein Is Associated with Resistance of Leukemia Cells to CTL-Mediated Cytolysis

To improve cancer immunotherapy, it is important to understand how tumor cells counteract immune-surveillance. In this study, we sought to identify cell-surface molecules associated with resistance of leukemia cells to cytotoxic T cell (CTL)-mediated cytolysis. To this end, we first established thousands of monoclonal antibodies (mAbs) that react with MLL/AF9 mouse leukemia cells. Only two of these mAbs, designated R54 and B2, bound preferentially to leukemia cells resistant to cytolysis by a tumor cell antigen–specific CTLs. The antigens recognized by these mAbs were identified by expression cloning as the same protein, CD43, although their binding patterns to subsets of hematopoietic cells differed significantly from each other and from a pre-existing pan-CD43 mAb, S11. The epitopes of R54 and B2, but not S11, were sialidase-sensitive and expressed at various levels on leukemia cells, suggesting that binding of R54 or B2 is associated with the glycosylation status of CD43. R54^high leukemia cells, which are likely to express sialic acid-rich CD43, were highly resistant to CTL-mediated cytolysis. In addition, loss of CD43 in leukemia cells or neuraminidase treatment of leukemia cells sensitized leukemia cells to CTL-mediated cell lysis. These results suggest that sialic acid-rich CD43, which harbors multiple sialic acid residues that impart a net negative surface charge, protects leukemia cells from CTL-mediated cell lysis. Furthermore, R54^high or B2^high leukemia cells preferentially survived in vivo in the presence of adaptive immunity. Taken together, these results suggest that the glycosylation status of CD43 on leukemia is associated with sensitivity to CTL-mediated cytolysis in vitro and in vivo. Thus, regulation of CD43 glycosylation is a potential strategy for enhancing CTL-mediated immunotherapy.     

Dapagliflozin,a Sodium-Glucose Co-Transporter 2 Inhibitor,Acutely Reduces Energy Expenditure in BAT via Neural Signals in Mice

Selective sodium glucose cotransporter-2 inhibitor (SGLT2i) treatment promotes urinary glucose excretion, thereby reducing blood glucose as well as body weight. However, only limited body weight reductions are achieved with SGLT2i treatment. Hyperphagia is reportedly one of the causes of this limited weight loss. However, the effects of SGLT2i treatment on systemic energy expenditure have not been fully elucidated. Herein, we investigated the acute effects of dapagliflozin, a SGLT2i, on systemic energy expenditure in mice. Eighteen hours after dapagliflozin treatment oxygen consumption and brown adipose tissue (BAT) expression of ucp1, a thermogenesis-related gene, were significantly decreased as compared to those after vehicle treatment. In addition, dapagliflozin significantly suppressed norepinephrine (NE) turnover in BAT and c-fos expression in the rostral raphe pallidus nucleus (rRPa) which contains the sympathetic premotor neurons responsible for thermogenesis. These findings indicate that the dapagliflozin-mediated acute decrease in energy expenditure involves a reduction in BAT thermogenesis via decreased sympathetic nerve activity from the rRPa. Furthermore, common hepatic branch vagotomy abolished the reductions in ucp1 expression and NE contents in BAT and c-fos expression in the rRPa. In addition, alterations in hepatic carbohydrate metabolism, such as decreases in glycogen contents and upregulation of phosphoenolpyruvate carboxykinase, manifested prior to the suppression of BAT thermogenesis, e.g. 6 hours after dapagliflozin treatment. Collectively, these results suggest that SGLT2i treatment acutely suppresses energy expenditure in BAT via regulation of an inter-organ neural network consisting of the common hepatic vagal branch and sympathetic nerves.