Sensitivity of Prestin-Based Membrane Motor to Membrane Thickness

Prestin is the membrane protein in outer hair cells that harnesses electrical energy by changing its membrane area in response to changes in the membrane potential. To examine the effect of membrane thickness on this protein, phosphatidylcholine (PC) with various acyl-chain lengths were incorporated into the plasma membrane by using γ-cyclodextrin. Incorporation of short chain PCs increased the linear capacitance and positively shifted the voltage dependence of prestin, up to 120 mV, in cultured cells. PCs with long acyl chains had the opposite effects. Because the linear capacitance is inversely related to the membrane thickness, these voltage shifts are attributable to membrane thickness. The corresponding voltage shifts of electromotility were observed in outer hair cells. These results demonstrate that electromotility is extremely sensitive to the thickness of the plasma membrane, presumably involving hydrophobic mismatch. These observations indicate that the extended state of the motor molecule, which is associated with the elongation of outer hair cells, has a conformation with a shorter hydrophobic height in the lipid bilayer.     

Highly glucose tolerant β-glucosidase from Aspergillus unguis: NII 08123 for enhanced hydrolysis of biomass

Aspergillus unguis NII-08123, a filamentous fungus isolated from soil, was found to produce β-glucosidase (BGL) activity with high glucose tolerance. Cultivation of the fungus in different carbon sources resulted in the secretion of different isoforms of the enzyme. A low molecular weight isoform, which retained ~60 % activity in the presence of 1.5 M glucose, was purified to homogeneity and the purified enzyme exhibited a temperature and pH optima of 60 °C and 6, respectively. The K _m and V _max of the enzyme were 4.85 mM and 2.95 U/mg, respectively, for 4-nitrophenyl β-d-glucopyranoside. The glucose inhibition constant of the enzyme was 0.8 M, indicating high glucose tolerance, and this is the second-highest glucose tolerance ever reported from the Aspergillus nidulans group. The glucose-tolerant BGL from A. unguis, when supplemented to cellulase preparation from Penicillium, could improve biomass hydrolysis efficiency by 20 % in 12 h compared to the enzyme without additional beta glucosidase supplementation. The beta glucosidase from A. unguis is proposed as a highly potent “blend-in” for biomass saccharifying enzyme preparations.     

Changes in the Chlorophyll Contents of Leaves and in Levels of Cytokinins in Root Exudates during Ripening of Rice Cultivars Nipponbare and Akenohoshi

Changes in fluxes of cytokinins in exudates transported viathe xylem from roots of rice plants cvs. Nipponbare (a standardJapanese cultivar) and Akenohoshi (a slowly senescing cultivar)were measured by mass spectrometry with deuterium-labeled standards.The fluxes of zeatin (Z), trans-ribosylzeatin (trans-RZ), N⁶-isopentenyladenine(iP), and "conjugated Z" (Z in the hydrolysates of highly polarfractions) decreased from heading to the late ripening stagein both cultivars. At the late ripening stage, iP and Z couldno longer be detected, while the flux of N⁶-isopentenyladenosine(iPA) increased slightly. In Akenohoshi, conjugated Z was thepredominant cytokinin from heading to the middle of the ripeningstage. The flux of each of the cytokinins in Akenohoshi washigher than that in Nipponbare at every time point, with theexception of the flux of iPA just after heading. The total concentrationof cytokinins in the xylem exudate of Akenohoshi was higherthan that of Nipponbare after the middle of ripening stage.The chlorophyll content of the third leaves, which were senescingrapidly, was significantly correlated with the flux of totalcytokinins per plant or per unit leaf area. These results suggestthat the larger amounts of cytokinins, in particular conjugatedZ, transported from the roots to the shoots caused the slowsenescence of leaves in Akenohoshi during the ripening stage. (Received May 9, 1994; Accepted July 1, 1995)     

Preparation and antitumor activity of nontoxic lipid A

Summary Highly refined, disaggregated endotoxic glycolipids (B5) from heptose-less (Re) mutant Salmonella typhimurium quantitatively converted to nontoxic (lethality for chick embryos) and nonpyrogenic (fever in rabbits) lipid A by treatment with boiling 0.1 N HCl (B5-HC1). Nontoxic B5-HCl, like toxic B5, caused regression of line-10 tumors and elimination of lymph node metastasis in 27 of 32 (84%) syngeneic strain 2 guinea pigs at a dosage of 150 g. At this dosage, toxic B5 led to a cure in 54 of 67 (81%) tumor-bearing animals. All cured animals rejected a second line-10 tumor cell transplant. This activity depended on combining the toxic or nontoxic endotoxins with mycobacterial trehalose mycolate (P3) and an essentially nontoxic peptide-containing side-fraction (ACP) recovered during the isolation of B5. In contrast to toxic B5 or endotoxins in general, nontoxic B5-HCl did not cause endotoxic shock when combined with adjuvant dipeptide (MDP) and injected IV into guinea pigs. Chemical analysis showed that the phosphate content of nontoxic B5-HCl was about one-half that observed in toxic B5 or in toxic KDO-free lipid A, which was obtained by treating toxic B5 with sodium acetate at pH 4.5 at 100° C (B5-pH 4.5). The molar ratio of glucosamine: phosphorus: fatty acids was 2:1:4 for nontoxic B5-HCl and was 2:2:4 for toxic B5-pH 4.5. These results demonstrate that endotoxic extracts could be selectively detoxified while retaining antitumor properties. Thus, nontoxic B5-HCl may be a potential candidate for immunotherapy of human cancer.Presented at the 72nd Annual Meeting of the American Association for Cancer Research, 1981, and abstract no. 1123 published in the Proceedings of the American Association for Cancer Research, Vol. 22, 1981 Abbreviations used in this paper: ACP, a nontoxic acetone-chloroform precipitated side-fraction of endotoxin that contains (an) ingredient(s) necessary for tumor regression of line-10 tumors in strain 2 guinea pigs; ReGl, endotoxic glycolipids from Re mutant gram-negative bacteria; ReGl-PCP, ReGl extracted with phenol-chloroform-petroleum ether (PCP); B5, refined endotoxin, free of phospholipids, divalent cations and disaggregated; B5-HCl, nontoxic lipid A prepared from B5 by treatment with hydrochloric acid; B5-pH 4.5, toxic lipid A prepared from B5 by treatment with sodium acetate at pH 4.5; lipid A, hydrochloric acid or sodium acetate hydrolysate of ReGl-PCP or B5; MDP, N-acetyl-muramyl-l-seryl-d-isoglutamine; KDO, keto-3-deoxyoctonate     

Local signal time-series during rest used for areal boundary mapping in individual human brains

It is widely thought that resting state functional connectivity likely reflects functional interaction among brain areas and that different functional areas interact with different sets of brain areas. A method for mapping areal boundaries has been formulated based on the large-scale spatial characteristics of regional interaction revealed by resting state functional connectivity. In the present study, we present a novel analysis for areal boundary mapping that requires only the signal timecourses within a region of interest, without reference to the information from outside the region. The areal boundaries were generated by the novel analysis and were compared with those generated by the previously-established standard analysis. The boundaries were robust and reproducible across the two analyses, in two regions of interest tested. These results suggest that the information for areal boundaries is readily available inside the region of interest.     

Comparison of Attenuation of Striated Muscle between Postmortem and Antemortem Computed Tomography: Results of a Longitudinal Study

Objective

We evaluated the postmortem changes of striated muscle by comparing computed tomography (CT) images obtained postmortem and antemortem in the same patients.

Materials and Methods

We studied 33 consecutive patients who underwent antemortem CT, postmortem CT, and pathological autopsy in our tertiary care hospital between April 2009 and December 2010. Postmortem CT was performed within 20 h after death and was followed by pathological autopsy. Pathological autopsy confirmed the absence of muscular diseases such as amyotrophic lateral sclerosis, muscular dystrophy, myositis, and myasthenia, in all of the patients. The CT attenuation values of four cardiac muscle sites (anterior wall of the left ventricle, left ventricular free wall, posterior wall of the left ventricle, and the ventricular septum) and two skeletal muscle sites (the pectoralis major muscle and the erector spinae muscle) were compared between antemortem and postmortem CT using paired t test.

Results

Striated muscle had significantly greater attenuation on postmortem CT than on antemortem CT (P<0.001) in all six tissue sites. No significant association was found between postmortem change in the CT attenuation of striated muscle and gender, age, or elapsed time since death.

Conclusion

This is the first longitudinal study to show hyperattenuation of striated muscle on postmortem CT images compared with antemortem CT images in the same patients.     

Brain Swelling and Loss of Gray and White Matter Differentiation in Human Postmortem Cases by Computed Tomography

The purpose of this study was to evaluate the brain by postmortem computed tomography (PMCT) versus antemortem computed tomography (AMCT) using brains from the same patients. We studied 36 nontraumatic subjects who underwent AMCT, PMCT, and pathological autopsy in our hospital between April 2009 and December 2013. PMCT was performed within 20 h after death, followed by pathological autopsy including the brain. Autopsy confirmed the absence of intracranial disorders that might be related to the cause of death or might affect measurements in our study. Width of the third ventricle, width of the central sulcus, and attenuation in gray matter (GM) and white matter (WM) from the same area of the basal ganglia, centrum semiovale, and high convexity were statistically compared between AMCT and PMCT. Both the width of the third ventricle and the central sulcus were significantly shorter in PMCT than in AMCT (P < 0.0001). GM attenuation increased after death at the level of the centrum semiovale and high convexity, but the differences were not statistically significant considering the differences in attenuation among the different computed tomography scanners. WM attenuation significantly increased after death at all levels (P<0.0001). The differences were larger than the differences in scanners. GM/WM ratio of attenuation was significantly lower by PMCT than by AMCT at all levels (P<0.0001). PMCT showed an increase in WM attenuation, loss of GM–WM differentiation, and brain swelling, evidenced by a decrease in the size of ventricles and sulci.     

Expression of asparagine synthetase in rice (Oryza sativa) roots in response to nitrogen

The expression of asparagine synthetase (AS; EC 6.3.5.4) in response to externally supplied nitrogen was investigated with respect to enzyme activity and protein levels as detected immunologically in rice ( Oryza sativa ) seedlings. The asparagine content was very low in leaves and roots of nitrogen-starved rice plants but increased significantly after the supply of 1 m M NH₄⁺ to the nutrient solution. While neither AS activity nor AS protein could be detected in leaves and roots prior to the supply of nitrogen, levels became detectable in roots but not in leaves within 12 h of the supply of 1 m M NH₄⁺ or 10 m M glutamine. Other nitrogen compounds, such as nitrate, glutamate, aspartate and asparagine had no effect. Methionine sulfoximine completely inhibited the NH₄⁺-induced accumulation of AS protein but did not affect the glutamine-induced accumulation of the enzyme. The results suggested that glutamine or glutamine-derived metabolites regulate AS expression in rice roots.     

Relationship between leaf and xylem water potentials in rice plants

Leaf and xylem water potentials were measured in rice plantswith and without transpiration using a thermocouple psychrometerand a pressure chamber. The leaf water potential practicallycoincided with the xylem water potential in leaves without transpiration,while the latter was 3–5 bars lower when intense transpirationwas occurring. The pressure chamber should not be used to measureleaf water potential during intense transpiration in the field.The water status in transpiring leaves is discussed. (Received March 6, 1978; )     

Two species of Drepanopus Brady (Copepoda Calanoida) with discrete ranges in the Southern Hemisphere

Morphological features, distributional records and developmentalstages of Drepanopus pectinatus Brady and D. forcipatus Giesbrechtindicate their close relationship but also corroborate the validityof their states as separate species with discrete ranges. D.pectinatus lives in inshore waters of the Crozet, Kerguelenand Heard Islands, south of the Antarctic Convergence. D. forcipatusoccurs along both the Pacific and thc Atlantic coasts of southernSouth America and around South Georgia. The distribution ofthe species in the former region, which includes the FalklandIslands, appears to be related to the extent of the continentalshelf and of the sub-Antarctic water; South Georgia lies southof the Antarctic Convergence. Significant morphometric differencesbetween both populations of D. forcipatus were found.