The effect of Sa modification with NEM, which activates Mg2+-ATPase through an enhancement of the association of actin and myosin, was investigated on the superprecipitation, clearing and Mg2+-ITPase of myosin B with reference to the effect of S1-blocking. 1. Superprecipitation induced by ATP was markedly enhanced by Sa-blocking even at high concentrations of Mg2+ and substrate; this may be due to an increase in the affinity of myosin and actin on blocking Sa. 2. Nevertheless, neither ITP-induced superprecipitation nor Mg2+-ITPase was affected by Sa modification. 3. Blocking of S1 brought about the inhibition of ATP- and ITP-induced superprecipitation and Mg2+-ITPase activity, suggesting that S1-blocking decreases the affinity of myosin and actin. 4. Sa-blocked myosin B showed greater resistance to clearing by ATP, especially in the presence of Ca2+ ions, whereas in the clearing response of actomyosin gel to PPi no difference between Sa-blocked and unmodified myosins B was observed. On the other hand, the clearing response of myosin B became more sensitive to both ATP and PPi on blocking S1. Based on the above results and preliminary data suggesting that Sa is located in LMM, the interaction of myosin filaments and actin filaments under physiological conditions is discussed.
To clarify further the mechanism of Mg2+ activation of myosin B by the modification of Sa, a specific sulfhydryl group in the light meromyosin (LMM) region, the properties of Sa blocked myosin B, myosin A, and LMM were investigated in comparison with those of unmodified materials and the following results were obtained. An Arrhenius plot of Mg2+-ATPase activity of myosin B showed that the frequency factor became larger on blocking Sa whereas the activation energy was not affected. Mg2+ATPase activity of myosin B as well as Mg activity was activated by the modification, whereas Mg2+ activity was not affected. The inhibition of Mg2+ activity of myosin B at higher magnesium concentration disappeared on entrapment of myosin B into agarose gel, and even an entrapped and unmodified sample had the same Mg concentration dependency as that of soluble Sa myosin B. The Mg2+-ATPase activity of modified myosin A separated from S myosin B was rapidly enhanced and saturated by a lower concentration of actin than that for unmodified myosin A. It was shown by electron microscopy that myosin and actin filaments of Sa myosin B in the presence of Mg2+ gathered in parallel while in the case of unmodified myosin B they dispersed each other. Synthetic myosin filaments and LMM paracrystals of Sa materials were indistinguishable from those of the unmodified compounds electron microscopically. Based on these results and previously described properties of Sa myosin B, the mechanism of the participation of Sa in the myosin-actin interaction is discussed.
Journal Article Effect of Diazonium Derivatives on Myosin A Adenosine Triphosphatase: I. Effect of Diazobenzene-p-sulfonate Modification on the Activation of Myosin A ATPase by Activators Get access TATSUHISA YAMASHITA, TATSUHISA YAMASHITA Department of Biochemistry, School of Medicine, Juntendo UniversityBunkyo-ku, Tokyo Search for other works by this author on: Oxford Academic PubMed Google Scholar IZUMI KABASAWA, IZUMI KABASAWA Department of Biochemistry, School of Medicine, Juntendo UniversityBunkyo-ku, Tokyo Search for other works by this author on: Oxford Academic PubMed Google Scholar TAKAMITSU SEKINE TAKAMITSU SEKINE Department of Biochemistry, School of Medicine, Juntendo UniversityBunkyo-ku, Tokyo Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Biochemistry, Volume 63, Issue 5, May 1968, Pages 608–616, https://doi.org/10.1093/oxfordjournals.jbchem.a128819 Published: 01 May 1968 Article history Received: 08 July 1967 Published: 01 May 1968
Abstract We have introduced behavior therapy as standard in‐patient treatment for anorexia nervosa and have modified the treatment program. At first, we used Fukamachi's activity restriction therapy (FT), followed by Token economy therapy (TET), which combined token economy with FT. Finally, we have developed Kyoto Prefectural University of Medicine Behavior Therapy (KPT). According to KPT, only liquid formula is given in the early stages of hospitalization and a target weight is not set at admission. We examined the effect of these three programs with respect to bodyweight gain. Thirty‐five anorexic patients participated in these three programs in our hospital: seven completed FT, seven completed TET and 21 coompleted KPT. We compared the effects of these three programs on body mass index (BMI). Furthermore, the effects of these three programs on BMI were compared at admission, 1 month after admission and at discharge, 6 months after discharge. In addition, the rate of increase of BMI for the following three periods was investigated: 1 month after admission, total hospitalization (from admission to discharge) and from admission to 6 months after discharge. The result is that KPT was the most effective of the three programs with regard to both the amount and the rate of increase of BMI at all points and there is a significant difference between KPT and FT. This effectiveness may be attributable to the use of an oral liquid formula, the setting of target weight at a later stage of hospitalization and the release of activity restriction based on weight gain.
A higher prevalence of smoking among schizophrenic patients has been well documented in Japan and other countries. Smoking reduction or cessation is desirable to reduce various physical complications in schizophrenic patients, but the effect of smoking reduction on psychiatric status and BMI remains ambiguous. The aim of this study was to determine the effect of an institutional smoking prohibition on smoking status, psychiatric status and BMI in Japanese inpatients with schizophrenia.Smoking status, psychiatric status (Clinical Global Impression (CGI) scores: global severity score and global change score) and BMI were investigated in 256 chronic schizophrenic inpatients before and 3 months after prohibition of smoking in a Japanese psychiatric hospital building.Following prohibition, the smoking rate decreased from 36.3% to 22.2%. A weak positive correlation was found between decreased cigarette consumption and the CGI global change score (r=0.140, p=0.025), but the mean global change scores in the smoking groups were less than 6 (minimally worse). No significant increase in BMI was observed.Institutional smoking prohibition is effective in reducing the smoking rate, while having only a minor unfavorable effect on psychiatric status and BMI in chronic schizophrenic inpatients.
Using type IV collagen-Sepharose affinity chromatography, the binding proteins were isolated from 125I surface-labeled human neutrophils. SDS-polyacrylamide gel electrophoresis analysis showed that the binding molecules were composed of the 28-, 49-, 67-, and 95-kDa proteins. Western blot analysis revealed that the 95-kDa proteins contained both L-selectin and nonspecific cross-reacting antigen 90 (NCA90), and that the 67-kDa protein was corresponded to 67-kDa elastin/laminin receptor (67BP) . When f-Met-Leu-Phe (fMLP) -stimulated neutrophils were analyzed using the affinity chromatography, the amounts of the binding proteins were increased about three-fold. However, western blot analysis demonstrated that L-selectin was significantly decreased by the fMLP stimulation. On the other hand, NCA90 and 67BP were increased by the stimulation. Together these observations indicate that neutrophils have several kinds of the adhesion molecules to type IV collagen, and that L-selectin is likely important for the binding of resting neutrophils to type IV collagen, whereas 67BP and NCA90 are likely important for the binding of stimulated neutrophils to type IV collagen.
Bradykinin-inactivating activity of mononuclear leukocytes was examined using guinea-pig macrophages and lymphocytes. Intact macrophages rapidly inactivated bradykinin. Bradykinin-inactivating activity of macrophages was present in the membrane and cytosol fractions but not in the nuclear and granular fractions. The bradykinin-inactivating activity of the membrane fraction was inhibited by captopril, whereas that of the cytosol fraction was inhibited by N-ethylmaleimide. Bradykinin-inactivating activity of intact macrophages was inhibited by captopril but not by N-ethylmaleimide, suggesting that the membranebound bradykinin-inactivating enzyme rather than the cytosol bradykinin-inactivating enzyme is responsible for the inactivation of bradykinin by intact macrophages. Although intact lymphocytes hardly inactivated bradykinin, lymphocytes contained a bradykinin-inactivating activity in the cytosol fraction but not in the nuclear and particulate fractions. The bradykinin-inactivating enzyme of the lymphocyte cytosol fraction was inhibited by N-ethylmaleimide, and this enzyme was hardly released extracellularly from intact cells during incubation of lymphocytes with bradykinin.
Guinea-pig platelets contain adherence-inhibiting factor (AIF) in the granule and cytosol fractions. In this study, subgranular localization and properties of granular AIF were examined.Two AIF molecules, designated AIF-I (about void volume of the column) and AIF-II (about 12 kDa), were eluted, when platelet-granule fraction was subjected to a superose 12 gel chromatography. The neutrophil adherence-inhibiting activity of AIF-I was about fivefold higher than that of AIF-II . AIF-I was sensitive to diisopropylfluoro-phosphate (DFP) and localized in lysosomes, whereas AIF-II was insensitive to DFP and localized in α-granules. Both AIF-I and AIF-II inhibited neutrophil adherence to glass and polystyrene surfaces, but did not inhibit neutrophil adherence to fibronectin-coated polystyrene surface. AIF-II hardly affected neutrophil adherence to type IV collagen-coated polystyrene surface. In contrast, AIF-I significantly inhibited type IV collagen mediated neutrophil adherence.These results suggest that AIF-II only inhibits neutrophil adherence via nonspecific adsorption sites, whereas AIF-I inhibits neutrophil adherence both via nonspecific adsorption sites and type IV collagen receptors.
