scholarly journals Maximum activities and properties of glucose 6-phosphatase in muscles from vertebrates and invertebrates

1981 ◽  
Vol 198 (3) ◽  
pp. 621-629 ◽  
Author(s):  
B Surholt ◽  
E A Newsholme
Keyword(s):  
Flight Muscle ◽  
Schistocerca Gregaria ◽  
Pectoral Muscle ◽  
Hydrolytic Activity ◽  
Strong Positive Correlation ◽  
Ph Optimum ◽  
Futile Cycle ◽  
Avian Muscle ◽  
Glucose Phosphorylation ◽  
Almost All

1. The maximum catalytic activities of glucose 6-phosphatase were measured in a large number of muscles from vertebrates and invertebrates. The activities range from less than 0.1 to 8.0 mumol/min per g fresh wt. at 30 degrees C: the highest activity, observed in the flight muscle of the wasp (Vespa vulgaris), is similar to that in rat liver. The hydrolytic activity was shown to be specific towards glucose 6-phosphate. 2. The pH optimum was 6.8 and the Km was approx. 0.6 mM (flight muscle of a moth). 3. Almost all of the glucose 6-phosphatase activity from extracts of the flight muscle of a moth and the pectoral muscle of a pigeon were recovered in the cytosolic fraction (i.e. 150,000 g supernatant). 4. During development of the locust (Schistocerca gregaria), the activity of the phosphatase in the flight muscle increased during the first 3 days after the final moult. 5. The activity of glucose 6-phosphatase from insect and avian muscle was separated from that of non-specific phosphatase on a Bio-Gel P-100 column. 6. For the activities from 63 muscles, there was a strong positive correlation between those of glucose 6-phosphatase and hexokinase, but no correlation between the activities of glucose 6-phosphatase and fructose bisphosphatase. It is suggested that the role of glucose 6-phosphate in muscle is either to produce glucose from glucose 6-phosphate derived from glycogen or to provide the enzymic basis for a substrate (‘futile’) cycle between glucose and glucose 6-phosphatase in muscle to improve the sensitivity of the mechanism that regulates the rate of glucose phosphorylation.

scholarly journals Proctolin degradation by membrane peptidases from nervous tissues of the desert locust (Schistocerca gregaria)

1987 ◽  
Vol 245 (2) ◽  
pp. 365-370 ◽  
Author(s):  
R E Isaac
Keyword(s):  
Schistocerca Gregaria ◽  
Physiological Role ◽  
Hydrolytic Activity ◽  
Mitochondrial Fraction ◽  
Membrane Preparation ◽  
Aminopeptidase Activity ◽  
Synaptic Membrane ◽  
Desert Locust ◽  
Ph Optimum ◽  
Enzyme Preparations

The hydrolysis of the insect neuropeptide proctolin (Arg-Tyr-Leu-Pro-Thr) by enzyme preparations from the nervous tissue of the desert locust (Schistocerca gregaria) was investigated. Neural homogenate degraded proctolin (100 microM) at neutral pH by cleavage of the Arg-Tyr and Tyr-Leu bonds to yield Tyr-Leu-Pro-Thr, Arg-Tyr and free tyrosine. Arg-Tyr was detected as a major metabolite when the aminopeptidase inhibitors amastatin and bestatin were present to prevent Arg-Tyr breakdown. Around 50% of the proctolin-degrading activity was isolated in a 30,000 g membrane fraction and was shown to be almost entirely due to aminopeptidase activity. The aminopeptidase had an apparent Km of 23 microM, a pH optimum of 7.0 and was inhibited by 1 mM-EDTA and amastatin [IC50 = 0.3 microM], but was relatively insensitive to bestatin, actinonin and puromycin. Phenylmethanesulphonyl fluoride (1 mM) and p-chloromercuriphenylsulphonic acid (1 mM) had no effect on this enzyme activity. Although the bulk of the Tyr-Leu hydrolytic activity was located in the 30,000 g supernatant, some weak activity was detected in a washed membrane preparation. This peptidase displayed a high affinity for proctolin (Km = 0.35 microM) and optimal activity at around pH 7.0. Synaptosome- and mitochondria-rich fractions were prepared from crude neural membranes. The aminopeptidase activity was concentrated in the synaptic-membrane preparation, whereas activity giving rise to Arg-Tyr was predominantly localized in the mitochondrial fraction. The subcellular localization of the membrane aminopeptidase is consistent with a possible physiological role for this enzyme in the inactivation of synaptically released proctolin.

A method for determining the periodicity of a troponin component in isolated insect flight muscle thin filaments by gold/Fab labelling

1992 ◽  
Vol 101 (3) ◽  
pp. 503-508
Author(s):  
R. Newman ◽  
G.W. Butcher ◽  
B. Bullard ◽  
K.R. Leonard
Keyword(s):  
Gold Particle ◽  
Colloidal Gold ◽  
Striated Muscle ◽  
Flight Muscle ◽  
Insect Flight ◽  
Insect Flight Muscle ◽  
Fab Fragment ◽  
Thin Filaments ◽  
Gold Particles ◽  
Almost All

Insect flight muscle has a large component (Tn-H) in the tropomyosin-troponin complex that is not present in vertebrate striated muscle thin filaments. Tn-H is shown by gold/Fab labelling to be present at regular intervals in insect flight muscle thin filaments. The Fab fragment of a monoclonal antibody to Tn-H was conjugated directly with colloidal gold and this probe used to label isolated thin filaments from the flight muscle of Lethocerus indicus (water bug). The distribution of gold particles seen in electron microscope images of negatively stained thin filaments was analysed to show that the probe bound to sites having a periodicity of approximately 40 nm, which is the expected value for the tropomyosin-troponin repeat. Conjugates of Fab with colloidal gold particles of 3 nm diameter labelled almost all sites. Conjugates with gold particles of 5 nm and 10 nm diameter labelled less efficiently (70% and 30%, respectively) but analysis of the distribution of inter-particle intervals among a number of filaments again gave the same fundamental spacing of 40 nm. The error in the measurements (standard deviation approximately +/− 4.2 for 5 nm gold/Fab) is less than earlier estimates for the size of the gold/Fab complex. Measurements on gold/Fab in negative stain suggest that the bound Fab contributes a shell about 2 nm in thickness around the gold particle. The radius of the probe (about 4.5 nm for 5 nm gold/Fab) would then be consistent with the value of error found. The size of the probe suggests that the gold particle binds to the side of the Fab molecule, rather close to the antibody combining site. The potential resolution of the technique may thus be better than originally expected.

scholarly journals Economic fluctuations and crime: temporary and persistent effects

2016 ◽  
Vol 43 (4) ◽  
pp. 609-623 ◽  
Author(s):  
Keith Bender ◽  
Ioannis Theodossiou
Keyword(s):  
Design Methodology ◽  
Economic Fluctuations ◽  
Strong Positive Correlation ◽  
Dynamic Interactions ◽  
Content Type ◽  
Persistent Effect ◽  
Long Run ◽  
Unemployment And Crime ◽  
Ambiguous Effect ◽  
Almost All

Purpose Since the literature on the effect of the unemployment rate as reflection of economic fluctuations on crime shows an empirically ambiguous effect, the purpose of this paper is to argue that a new way of modeling the dynamics of unemployment and crime by focussing on the transitory and persistent effect of unemployment on crime helps resolve this ambiguity. Design/methodology/approach Panel data for US states from 1965 to 2006 are examined using the Mundlak (1978) methodology to incorporate the dynamic interactions between crime and unemployment into the estimation. Findings After decomposing the unemployment effect on crime into a transitory and persistent effect, evidence of a strong positive correlation between unemployment and almost all types of crime rates is unearthed. This evidence is robust to endogeneity and the controlling for cross-panel correlation and indicators for state imprisonment. Originality/value The paper is the first to examine the dynamics of the interaction of crime and economic fluctuations using the temporary and persistent effects framework of Mundlak (1978). In one set of estimates, one can evaluation both the short- and long-run effects of changes of unemployment on crime.

Physicochemical properties of a novel α-L-arabinofuranosidase fromRhizomucor pusillusHHT-1

2001 ◽  
Vol 47 (8) ◽  
pp. 767-772 ◽  
Author(s):  
A KM Shofiqur Rahman ◽  
Shinya Kawamura ◽  
Masahiro Hatsu ◽  
M M Hoq ◽  
Kazuhiro Takamizawa
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Molecular Mass ◽  
Gel Filtration ◽  
Hydrolytic Activity ◽  
Exchange Chromatography ◽  
Ph Optimum ◽  
Rhizomucor Pusillus ◽  
Terminal Amino ◽  
Metal Cofactors

The zygomycete fungus Rhizomucor pusillus HHT-1, cultured on L(+)arabinose as a sole carbon source, produced extracellular α-L-arabinofuranosidase. The enzyme was purified by (NH4)2SO4fractionation, gel filtration, and ion exchange chromatography. The molecular mass of this monomeric enzyme was 88 kDa. The native enzyme had a pI of 4.2 and displayed a pH optimum and stability of 4.0 and 7.0–10.0, respectively. The temperature optimum was 65°C, and it was stable up to 70°C. The Kmand Vmaxfor p-nitrophenyl α-L-arabinofuranoside were 0.59 mM and 387 µmol·min–1·mg–1protein, respectively. Activity was not stimulated by metal cofactors. The N-terminal amino acid sequence did not show any similarity to other arabinofuranosidases. Higher hydrolytic activity was recorded with p-nitrophenyl α-L-arabinofuranoside, arabinotriose, and sugar beet arabinan; lower hydrolytic activity was recorded with oat–spelt xylan and arabinogalactan, indicating specificity for the low molecular mass L(+)-arabinose containing oligosaccharides with furanoside configuration.Key words: α-L-arabinofuranosidase, enzyme purification, amino acid sequence, Rhizomucor pusillus.

scholarly journals The mechanism of C-20 hydroxylation of α-ecdysone in the desert locust, Schistocerca gregaria

1977 ◽  
Vol 168 (3) ◽  
pp. 513-520 ◽  
Author(s):  
P Johnson ◽  
H H Rees
Keyword(s):  
Schistocerca Gregaria ◽  
Fat Body ◽  
Difference Spectrum ◽  
Maximum Activity ◽  
Malpighian Tubules ◽  
Desert Locust ◽  
Ph Optimum ◽  
Developmental Variation ◽  
Moulting Hormone ◽  
Cytochrome P 450

1. The C-20 hydroxylation of alpha-ecdysone to produce beta-ecdysone was investigated in the desert locust, Schistocerca gregaria. 2. alpha-Ecdysone C-20 hydroxylase activity was located primarily in the fat-body and Malpighian tubules. The properties of the hydroxylation system from Malpighian tubules investigated further. 3. The enzyme system was mitochondrial, had a pH optimum of 6.5, an apparent Km of 12.5 micron and required O2 and NADPH. 4. The activity of the hydroxylation system showed developmental variation within the fifth instar, the maximum activity corresponding to the maximum tire of endogenous moulting hormone. The significance of these results is assessed in relation to the control of the endogenous titre of beta-ecdysone. 5. The mechanism of the hydroxylation system was investigated by using known inhibitors of hydroxylation reactions such as CO, metyrapone and cyanide. 6. The CO difference spectrum of the reduced mitochondrial preparation indicated the presence of cytochrome P-450 in the preparation. 7. It concluded that the alpha-ecdysone C-20 hydroxylase system is a cytochrome P-450-deendent mono-oxygenase.

The β-glucosidases of porcine kidney

1977 ◽  
Vol 55 (2) ◽  
pp. 140-145 ◽  
Author(s):  
Julian N. Kanfer ◽  
Richard A. Mumford ◽  
Srinivasa S. Raghavan
Keyword(s):  
Sodium Taurocholate ◽  
Hydrolytic Activity ◽  
Acidic Ph ◽  
Porcine Kidney ◽  
Ph Optimum ◽  
Pig Kidney ◽  
Competitive Inhibitors ◽  
Triton X ◽  
Hydrolysis Of ◽  
Estradiol 17Β

Some of the properties of a partially purified particle bound and soluble β-glucosidase (EC 3.2.1.21) from pig kidney were compared. The soluble β-glucosidase (1) hydrolyzed 4-methylumbelliferyl-β-D-glucoside (4-MU-β-D-glucoside) 17α-estradiol 3β-glucoside, 17α-estradiol 17β-glucoside, and salicin, but not glucosylceramide, (2) possessed a broad pH optimum (5.5–7.0), (3) had an isoelectric point of 4.9, and (4) was inhibited by Triton X-100. Several compounds were found to be competitive inhibitors of its hydrolytic activity, gluconolactam and estrone β-glucoside being the most effective. In contrast, a particulate β-glucosidase purified from the same tissue (1) had an acidic pH optimum (5.0), (2) was stimulated by sodium taurocholate and 'Gaucher's factor' for the hydrolysis of both 4-MU-β-glucoside and glucosylceramide, and (3) was capable of catalyzing a transglucosylation reaction employing 4-MU-β-D-glucoside or glucosylceramide as the glucosyl donor, and [l4C]ceramide as acceptor.

scholarly journals Mechanisms of Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa: Results of the GERPA Multicenter Study

2020 ◽  
Author(s):  
Damien Fournier ◽  
Romain Carrière ◽  
Maxime Bour ◽  
Emilie Grisot ◽  
Pauline Triponney ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Hydrolytic Activity ◽  
Resistance Mechanisms ◽  
Group 3 ◽  
High Production ◽  
Resistant Strains ◽  
Recycling Pathway ◽  
French Hospital ◽  
Almost All ◽  
Moderately Resistant

Resistance mechanisms of Pseudomonas aeruginosa to ceftolozane/tazobactam (C/T) were assessed on a collection of 420 nonredundant strains non-susceptible to ceftazidime (MIC > 8 μg/ml) and/or imipenem (> 4 μg/ml), collected by 36 French hospital laboratories over a one month period (GERPA study). Rates of C/T resistance (MIC > 4/4 μg/ml) were equal to 10% in this population (42/420 strains), and 23.2% among the isolates resistant to both ceftazidime and imipenem (26/112). A first group of 21 strains (50%) was found to harbor various extended-spectrum β-lactamases (1 OXA-14; 2 OXA-19; 1 OXA-35; 1 GES-9; 3 PER-1), carbapenemases (2 GES-5; 1 IMP-8; 8 VIM-2), or both (1 VIM-2/OXA-35; 1 VIM-4/SHV-2a). All the strains of this group belonged to widely distributed epidemic clones (ST111, ST175, CC235, ST244, ST348, ST654), and were highly resistant to almost all the antibiotics tested except colistin. A second group was composed of 16 (38%) isolates moderately resistant to C/T (MIC from 8/4 to 16/4 μg/ml), of which 7 were related to international clones (ST111, ST253, CC274, ST352, ST386). As demonstrated by targeted mass spectrometry, cloxacillin-based inhibition tests and gene blaPDC deletion experiments, this resistance phenotype was correlated to an extremely high production of cephalosporinase PDC. In part accounting for this strong PDC upregulation, genomic analyses revealed the presence of mutations in regulator AmpR (D135N/G in 6 strains) and enzymes of the peptidoglycan recycling pathway such as AmpD, PBP4, and Mpl (9 strains). Finally, all the 5 (12%) remaining C/T resistant strains (group 3) appeared to encode PDC variants with mutations known to improve the hydrolytic activity of the β-lactamase to ceftazidime and C/T (F147L, ΔL223-Y226, E247K, N373I). Collectively, our results highlight the importance of both intrinsic and transferable mechanisms in C/T resistant P. aeruginosa. Which mutational events lead some clinical strains to massively produce the natural cephalosporinase PDC remains incompletely understood.

scholarly journals TEM-89 β-Lactamase Produced by a Proteus mirabilis Clinical Isolate: New Complex Mutant (CMT 3) with Mutations in both TEM-59 (IRT-17) and TEM-3

2001 ◽  
Vol 45 (12) ◽  
pp. 3591-3594 ◽  
Author(s):  
Catherine Neuwirth ◽  
Stephanie Madec ◽  
Eliane Siebor ◽  
Andre Pechinot ◽  
Jean-Marie Duez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Clinical Isolate ◽  
Amino Acid Substitution ◽  
Proteus Mirabilis ◽  
Hydrolytic Activity ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Clinical Strain ◽  
Almost All

ABSTRACT TEM-89 (CMT-3) is the first complex mutant β-lactamase produced by a clinical strain of Proteus mirabilis (strain Pm 631). This new enzyme, which has a pI of 6.28, is derived from TEM-3 and has a single amino acid substitution also encountered in TEM-59 (inhibitor-resistant TEM β-lactamase IRT-17): Ser-130 to Gly. TEM-89 hydrolyzed penicillins to the same extent that TEM-3 did but lost almost all hydrolytic activity for cephalosporins and, like TEM-59, was highly resistant to inhibitors.

Religiosity and personal beliefs in ocd and anxiety disorders

2011 ◽  
Vol 26 (S2) ◽  
pp. 134-134
Author(s):  
A. Agorastos ◽  
S. Randjbar ◽  
C. Muhtz ◽  
L. Jelinek ◽  
M. Kellner ◽  
...  
Keyword(s):  
Anxiety Disorders ◽  
Strong Positive Correlation ◽  
Personal Beliefs ◽  
Magical Ideation ◽  
Positive Correlation ◽  
Face To Face ◽  
Paranormal Beliefs ◽  
Negative Religious Coping ◽  
Almost All ◽  
The Relationship

BackgroundIn the last decades the relationship between religiosity/spirituality (R/S), personal beliefs and mental health has been extensively studied, indicating a significant correlation of these variables. However, the specific relation of R/S to anxiety disorders has been less investigated.ObjectiveThe objective of this prospective study is the investigation of the relation of R/S, magical ideation (MI) and paranormal beliefs (PB) to anxiety disorders in general and OCD in particular, in order to specifically determine a possible impact of these variables on psychopathology scores. In addition, the relation between R/S, PB and MI can be systematically investigated.Design & methodUnselected samples with OCD and other anxiety disorders have been equally assessed within the first week after admission with a face-to-face interview including the following instruments: MINI, HAMD, HAMA and Y-BOCS, OCI-R, STAI, Brief Multidimensional Measure of Religiosity/Spirituality, Magical Ideation Scale and Revised Paranormal Beliefs Scale. Forty healthy participants with no psychiatric history served as controls.ResultsGroups did not differ in any aspect of R/S, MI, or PB. Almost all scales referring to R/S, PB and MI were positively correlated to each other. The results showed a strong positive correlation between high scores of negative religious coping and high psychopathology scores in depression and anxiety. On the other hand, there was a significant positive correlation between MI scores and initial OCD and anxiety scores.ConclusionThis study verifies a significant correlation between personal beliefs and psychopathology in OCD and anxiety disorders. Implications for further research are discussed.

Acid Phosphatase Activities in Developing Seeds of Pisum sativum L

1977 ◽  
Vol 4 (6) ◽  
pp. 843 ◽  
Author(s):  
DR Murray ◽  
MD Collier
Keyword(s):  
Acid Phosphatase ◽  
Pisum Sativum ◽  
Phosphatase Activity ◽  
Cell Expansion ◽  
Acid Phosphatase Activity ◽  
Minor Components ◽  
Ph Optimum ◽  
Pisum Sativum L ◽  
Almost All ◽  
Pea Seed

The seedcoats contain almost all of the acid phosphatase activity (EC 3.1.3.2) in the pea seed in the earliest stages of expansion. The seedcoat activity is maximal by the end of the period of rapid cell expansion and declines as the embryo matures. The developing cotyledons show a later rise in acid phosphatase activity to a maximum shortly before dehydration. The activity in the embryonic axis shows a marked increase only during dehydration. The acid phosphatase activity in the seedcoats results almost entirely from an isoenzyme with high electrophoretic mobility in 5.5% polyacrylamide gels (RF 0.97). This isoenzyme has not been detected in other tissues from the plant. The phosphatase activity in the cotyledons is accounted for by one major isoenzyme at RF 0.75 and by four minor components. The partially purified enzyme from the seedcoats shows a broad pH optimum from pH 5.0 to pH 6.0. In contrast, the preparation from the cotyledons has an optimum close to pH 5.6 and is slightly more sensitive to inhibition by 0.2 mM PI.

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