scholarly journals Inhibition of LPMOs by Fermented Persimmon Juice

Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1890
Author(s):  
Radina Tokin ◽  
Johan Ørskov Ipsen ◽  
Mahesha M. Poojary ◽  
Poul Erik Jensen ◽  
Lisbeth Olsson ◽  
...  
Keyword(s):  
Tannic Acid ◽  
Protein Interactions ◽  
Inhibitory Effect ◽  
Lytic Polysaccharide Monooxygenases ◽  
Mechanism Of Inhibition ◽  
Similar Inhibitory Effect ◽  
Dependent Inhibition ◽  
Polysaccharide Monooxygenases ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Fermented persimmon juice, Kakishibu, has traditionally been used for wood and paper protection. This protective effect stems at least partially from inhibition of microbial cellulose degrading enzymes. The inhibitory effect of Kakishibu on lytic polysaccharide monooxygenases (LPMOs) and on a cocktail of cellulose hydrolases was studied, using three different cellulosic substrates. Dose dependent inhibition of LPMO activity by a commercial Kakishibu product was assessed for the well-characterized LPMO from Thermoascus aurantiacus TaAA9A, and the inhibitory effect was confirmed on five additional microbial LPMOs. The model tannin compound, tannic acid exhibited a similar inhibitory effect on TaAA9A as Kakishibu. It was further shown that both polyethylene glycol and tannase can alleviate the inhibitory effect of Kakishibu and tannic acid, indicating a likely mechanism of inhibition caused by unspecific tannin–protein interactions.

Nickel inhibits endothelin-induced contractions of vascular smooth muscle

1990 ◽  
Vol 258 (6) ◽  
pp. C1025-C1030 ◽  
Author(s):  
K. Blackburn ◽  
R. F. Highsmith
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Isometric Force ◽  
Inhibitory Effect ◽  
Rat Aorta ◽  
Porcine Coronary Artery ◽  
Force Development ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Endothelin (ET)-induced contractions of vascular smooth muscle (VSM) are dependent on extracellular Ca2+ yet display only partial sensitivity to L-type Ca2+ antagonists. The purpose of this study was to evaluate the effect of nickel (Ni2+), a Ca2+ channel antagonist with clearly documented differential potency toward L- vs. T-type Ca2+ currents on ET-mediated contractions in VSM. Treatment of rings of left anterior descending porcine coronary artery (LAD) with Ni2+ produced a profound dose-dependent inhibition of isometric force development in response to porcine ET (ET-1). At a concentration of 360 microM, Ni2+ exerted a significant inhibitory effect on contracture in response to doses of ET-1 ranging from 3 to 100 nM. In contrast, the same concentration of Ni2+ failed to significantly affect peak force development in response to KCl depolarization (5-77 mM) or to phenylephrine (0.3-30 mM). In addition, 360 microM Ni2+ significantly inhibited the contractile response of rat aorta to 10 nM ET-1. We conclude that ET-1 activates a Ni2(+)-sensitive process in VSM which may signal an additional Ca2+ influx pathway that appears to be functionally distinct from the L-type Ca2+ channel.

Sodium cromoglycate: evidence of tachykinin antagonist activity in the human skin

1993 ◽  
Vol 75 (1) ◽  
pp. 167-172 ◽  
Author(s):  
D. C. Crossman ◽  
M. R. Dashwood ◽  
G. W. Taylor ◽  
R. Wellings ◽  
R. W. Fuller
Keyword(s):  
Sodium Cromoglycate ◽  
Human Skin ◽  
High Performance ◽  
Gel Filtration ◽  
Inhibitory Effect ◽  
Intradermal Injection ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

The mechanism of action of the antiasthmatic drug sodium cromoglycate (SCG) is unclear. One possibility is that SCG antagonizes the effects of the tachykinin substance P (SP), an agent known to cause airway edema. However, when SP is inhaled by humans, it has no demonstrable effect on airway function; therefore, the possibility that SCG prevents SP-induced changes in microvascular permeability was examined in human skin in vivo where potent edema-producing effects are seen. SCG (5–500 nmol) caused significant (P < 0.05) dose-dependent inhibition of SP-induced edema (wheal) formation when coadministered by intradermal injection. There was no effect on the nonreceptor-mediated flare response. SCG also significantly (P < 0.05) inhibited the wheal response to the related tachykinin neurokinin B but had no inhibitory effect on the cutaneous responses to histamine and prostaglandin E2. In addition, SCG (0.1–10 mM) caused dose-dependent inhibition of binding of SP labeled with 125I-labeled Bolton-Hunter to a number of tissues known to contain SP binding sites, as assessed by autoradiography. These concentrations were equivalent to the final concentrations of SCG found to inhibit the wheal response in the skin. The possibility that SCG interacted with SP was investigated both by gel filtration and high-performance liquid chromatography. No strong interaction was demonstrated with an 8,000 M excess of SCG under both hydrophobic and hydrophilic conditions. These results raise the possibility that SCG may have tachykinin antagonist properties.

Antiplatelet Effect of Hsien-Ho-T'sao (Agrimonia Pilosa)

1985 ◽  
Vol 13 (01n04) ◽  
pp. 109-118 ◽  
Author(s):  
Jih-Pyang Wang ◽  
Mei-Feng Hsu ◽  
Che-Ming Teng
Keyword(s):  
Platelet Rich Plasma ◽  
Atp Release ◽  
Water Extract ◽  
Creatine Phosphate ◽  
Inhibitory Effect ◽  
Malondialdehyde Formation ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Induced Aggregation ◽  
Dose Dependent

The water extract of Hsien-Ho-T'sao (HHT) produced a dose-dependent inhibition on collagen-induced aggregation of platelet-rich plasma (PRP). The IC50 was about 3.5 mg/ml. In addition, HHT inhibited also the aggregation induced by ADP, A23187 or arachidonate in PRP. Greater inhibition was observed in the preparation of washed platelets. Increase of the calcium concentration in medium could not overcome the inhibitory effect of HHT. ATP release from platelets induced by collagen or A23187 was inhibited by HHT. In the presence of EDTA, ATP release caused by thrombin or A23187 was also inhibited by HHT. Malondialdehyde and thromboxane B2 formation was greatly inhibited by HHT in platelets challenged by collagen and thrombin. In arachidonate-stimulated platelets, thromboxane B2, but not malondialdehyde formation was inhibited. HHT showed more marked inhibition on aggregation in the presence of indomethacin, creatine phosphate/creatine phosphokinase or a combination of both. Hydrogen peroxide-induced hemolysis was makred reduced by HHT. It was concluded that HHT might have some membrane-active properties which interfered with the activation of phospholipase A2.

Inhibition of sarcolemmal Na+-K+-ATPase by palmitoyl carnitine: potentiation by propranolol

1985 ◽  
Vol 248 (1) ◽  
pp. H75-H81
Author(s):  
J. H. Kramer ◽  
W. B. Weglicki
Keyword(s):  
Bovine Serum Albumin ◽  
Atpase Activity ◽  
Cardiac Myocytes ◽  
Inhibitory Effect ◽  
Inhibition Activity ◽  
Irreversible Inhibition ◽  
Palmitoyl Carnitine ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Native sarcolemma (SL) from adult canine cardiac myocytes (Na+-K+-ATPase activity 74.2 +/- 3.0 mumol X mg-1 X h-1) was preincubated (10 min, 37 degrees C, pH 7.2) with 1) 20-600 microM palmitoyl carnitine, 2) 250 nM-2.5 mM propranolol, or 3) 20-600 microM palmitoyl carnitine plus propranolol at various concentrations (0.0, 0.025, 0.25, 0.5, 1.0, and 2.5 mM); after preincubation, Na+-K+-ATPase activity was assayed. Palmitoyl carnitine alone (series 1) had no effect on ATPase activity over the range of 20-400 microM but was inhibitory (30%) at 600 microM. Propranolol alone (series 2) did not alter ATPase activity at any concentration. When SL membranes were exposed to both palmitoyl carnitine and propranolol (series 3), a dose-dependent inhibition of ATPase activity was observed. The inhibitory effect was not reversed by 3.0% bovine serum albumin. Propranolol concentrations greater than 0.025 mM significantly inhibited the activity of SL exposed to palmitoyl carnitine (above 150 microM). Palmitoyl carnitine and propranolol do not have to be added simultaneously to produce combined inhibition. Activity was inhibited 50% when SL were pretreated with 100 microM palmitoyl carnitine followed by addition of 2.5 mM propranolol no inhibition occurred if preincubation conditions were reversed. Thus exposure of SL to propranolol and reported physiological levels of palmitoyl carnitine leads to irreversible inhibition of the Na+-K+-ATPase, which may be due to the combined membrane-perturbant actions of these amphipathic agents.

Mepacrine Blockade of Arachidonate-lnduced Washed Platelet Aggregation: Relationship to Mepacrine Inhibition of Platelet Cyclooxygenase

1983 ◽  
Vol 50 (04) ◽  
pp. 784-786 ◽  
Author(s):  
Amiram Raz
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Thromboxane A2 ◽  
Inhibitory Effect ◽  
Thromboxane B2 ◽  
Concomitant Increase ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Arachidonate Release ◽  
Dose Dependent

SummaryMepacrine, in addition to its established antilipolytic activity, was also found to inhibit the conversion of 14C-arachidonic acid to 14C-thromboxane B2 in human washed platelets. In the concentration range of 3.33-33 μM, mepacrine exerted a dose dependent inhibition of arachidonate conversion to thromboxane B2 in parallel to inhibition of arachidonate-induced platelet aggregation. Mepacrine inhibition of thromboxane formation was not accompanied by a concomitant increase in other cyclooxygenase products. Furthermore, mepacrine did not affect platelet transformation of added prostaglandin H2 to thromboxane A2 and other products. These results indicate that mepacrine inhibits the cyclooxygenase enzyme and not thromboxane synthase. In washed platelets, mepacrine inhibition of arachidonic acid conversion to thromboxane A2 appears to be a major factor in the overall inhibitory effect of the compound on the combined process of arachidonate release from cellular phospholipids and its conversion to proaggregatory products.

Inhibition of boar sperm hyaluronidase activity by tannic acid reduces polyspermy during in vitro fertilization of porcine oocytes

Zygote ◽  
2006 ◽  
Vol 14 (4) ◽  
pp. 275-285 ◽  
Author(s):  
Hideki Tatemoto ◽  
Isao Tokeshi ◽  
Satoshi Nakamura ◽  
Norio Muto ◽  
Tadashi Nakada
Keyword(s):  
Tannic Acid ◽  
Penetration Rate ◽  
Vitro Fertilization ◽  
Hyaluronidase Activity ◽  
High Penetration ◽  
Boar Sperm ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

SummaryThe present study was conducted to examine the effects of three polyphenols (tannic acid, apigenin and quercetin) on hyaluronidase activity and in vitro fertilization (IVF) parameters. Among them, tannic acid showed by far the strongest potency for blocking hyaluronidase activity extracted from preincubated boar sperm, causing a dose-dependent inhibition over the range of 2–10 μg/ml. When cumulus-intact and cumulus-free oocytes were inseminated in IVF medium containing tannic acid, the penetration and the polyspermy rates were significantly decreased in the presence of 10 μg/ml tannic acid compared with those in the absence of tannic acid, and the addition of 5 μg/ml tannic acid significantly reduced the polyspermy rate (p < 0.05) compared with that of the control while maintaining the high penetration rate. However, apigenin and quercetin had no effect on the rate of polyspermy. Interestingly, the incidence of polyspermy was significantly reduced in oocytes inseminated with sperm pretreated with 5 μg/ml tannic acid (p < 0.05), although the pretreatment of oocytes had no effect against the polyspermy after insemination with untreated sperm. Treatment with tannic acid caused neither a protective proteolytic modification of the zona pellucida matrix before fertilization, nor a reduction of the proteolytic activity of acrosomal contents or the number of zona-bound spermatozoa. These data suggest that an appropriate concentration of tannic acid prevents polyspermy through the inhibition of sperm hyaluronidase activity during IVF of porcine oocytes.

Endotoxin Inhibits Prostacyclin Release From Rabbit Aorta

1981 ◽  
Author(s):  
J Zahavi ◽  
A C Honey ◽  
J Westwick ◽  
V V Kakkar
Keyword(s):  
Platelet Aggregation ◽  
Rabbit Aorta ◽  
Inhibitory Effect ◽  
White Female ◽  
Time Intervals ◽  
E Coli ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
The Mean ◽  
Dose Dependent

Released prostacyclin (PGI2) activity has been studied in aortic rings of 19 New Zealand white female rabbits. These rings produced a potent inhibitor of platelet aggregation, identified as PGI2. All the rabbits were anaesthetized with pentobarbital and thereafter a solution of endotoxin (E. Coli, 0111, B4, Difco Lab.) was injected intravenously to 7 rabbits (304μg/kg every 15 min during 1 hour to achieve an estimated plasma level of 1-2 μg/ml). Another 5 rabbits served as controls and were injected with saline. After 1 hour the aorta was rapidly excised, cleaned, cut into small rings and the released PGI2 activity studied at various time intervals (5-30 min) at 37°C. The mean release of PGI2 (in pg/mg wet tissue) in the control rabbits was 201 (range 50-443). It decreased significantly to 104 (range 0-237) after 30 min. In the endotoxaemic rabbits, the initial PGI2 release was only 73 (range 0-329) (p<0,008 compared to control rabbits). This level did not change with time and was 71.9 (range 0-261) after 30 min suggesting that the “endotoxinemic” vessels were initially relatively exhausted and were not able to release PGI2. In the remaining 7 rabbits the aorta was removed immediately after anaesthesia and aortic rings incubated for 5-30 min Krebs-Henleit buffer or endotoxin 0.2-10 μg/ml and the released PGI2 activity studied. There was a dose dependent inhibition which was more pronounced after 30 min incubation.The decrease in PGI2 release from rabbit aorta following endotoxaemia removes the inhibitory effect on platelet aggregation of the arterial vessel wall and consequently may contribute to the development of a thrombogenic state.

Dopaminergic modulation of respiratory motor output in peripherally chemodenervated goats

1998 ◽  
Vol 85 (3) ◽  
pp. 946-954 ◽  
Author(s):  
Ken D. O’Halloran ◽  
Patrick L. Janssen ◽  
Gerald E. Bisgard
Keyword(s):  
Carotid Body ◽  
Inhibitory Effect ◽  
Motor Output ◽  
High Dose ◽  
Inhibitory Effects ◽  
Before And After ◽  
Ventilatory Effect ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

We examined the ventilatory effects of exogenous dopamine (DA) and norepinephrine (NE) administration in chloralose-anesthetized, paralyzed, artificially ventilated adult goats before and after carotid body denervation (CBD). Intravenous (iv) DA bolus injections and slow iv infusions caused dose-dependent inhibition of phrenic nerve activity (PNA) in carotid body (CB)-intact animals during normoxia and hyperoxia but not during hypercapnia. NE administration in CB-intact goats caused dose-dependent inhibition of PNA of similar magnitude to DA trials. The DA D2-receptor agonists quinelorane and quinpirole inhibited PNA, whereas the DA D1-receptor agonist SKF-81297 had no effect. After CBD, the ventilatory depressant effects of DA persisted, but responses were significantly attenuated compared with CB-intact trials. CBD abolished the inhibitory effect of low-dose NE administration but did not alter ventilatory responses to high-dose NE injection. The peripheral DA D2-receptor antagonist domperidone substantially attenuated the inhibitory effects of DA bolus injections and infusions and reversed the inhibitory ventilatory effect of high-dose DA administration to excitation in some animals. The α-adrenoceptor antagonist phentolamine had no effect on DA-induced ventilatory depression. β-Adrenoceptor stimulation with isoproterenol produced similar hemodynamic effects to DA administration but had no effect on PNA. We conclude that DA and NE exert both CB-mediated and non-CB-mediated inhibitory effects on respiratory motor output in anesthetized goats. The ventilatory depressant effects that persist in peripherally chemodenervated animals are DA D2-receptor mediated, but their exact location remains speculative.

scholarly journals Influência do zinco sobre o efeito do selênio na atividade da enzima δ-ALA-D de fígado, rim e cérebro de camundongos adultos in vitro

2002 ◽  
Vol 24 (24) ◽  
pp. 49
Author(s):  
Nilda Vargas Barbosa ◽  
João Batista T. da Rocha
Keyword(s):  
Inhibitory Effect ◽  
Protective Role ◽  
Selenium Compounds ◽  
Organic Selenium ◽  
Inorganic Selenium ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Selenium is an essential dietary trace element and its deficiency can cause some pathologies such as cardiac diseases. However, investigations have evidencied the toxicologic effect of organic and inorganic selenium compounds in the organs and enzymes.The present work examined the toxic effect of selenium on δ-ALA-D an enzyme involved in the biosynthesis of tetrapyrrol heme. A possible protective role of zinc on inhibitory effect of selenium was also evaluated. The organic selenium compound, (CH3)2C (Seφ) (0CH3) caused a dose dependent inhibition of renal, hepatic and cerebral δ-ALA-D (p< 0.01). Also was evidencied that the selenium and zinc interaction not was able to restore the δ-ALA-D activity inhibited by selenium but increasing the inhibitory effect from the compound on the renal and cerebral enzyme.

Differences between antigenic determinants of pig and cat zona pellucida proteins

Reproduction ◽  
2000 ◽  
pp. 15-23 ◽  
Author(s):  
K Jewgenow ◽  
M Rohleder ◽  
I Wegner
Keyword(s):  
In Vitro Fertilization ◽  
Zona Pellucida ◽  
Antigenic Determinants ◽  
Vitro Fertilization ◽  
Contraceptive Vaccine ◽  
Sperm Binding ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Despite many efforts, the control of reproduction in feral cat populations is still a problem in urban regions around the world. Immunocontraception is a promising approach; thus the present study examined the suitability of the widely used pig zona pellucida proteins (pZP) for contraception in feral domestic cats. Purified zona pellucida proteins obtained from pig and cat ovaries were used to produce highly specific antisera in rabbits. Antibodies against pZP raised in rabbits or lions were not effective inhibitors of either in vitro sperm binding (cat spermatozoa to cat oocytes) or in vitro fertilization in cats, whereas antibodies against feline zona pellucida proteins (fZP) raised in rabbits showed a dose-dependent inhibition of in vitro fertilization. Immunoelectrophoresis, ELISA and immunohistology of ovaries confirmed these results, showing crossreactivity of anti-fZP sera to fZP and to a lesser extent to pZP, but no interaction of anti-pZP sera with fZP. It is concluded that cat and pig zonae pellucidae express a very small number of shared antigenic determinants, making the use of pZP vaccine in cats questionable. A contraceptive vaccine based on feline zona pellucida determinants will be a better choice for the control of reproduction in feral cats if immunogenity can be achieved.

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