scholarly journals Transglycosylation Properties of a Novel α-1,4-Glucanotransferase from Bacteroides thetaiotaomicron and Its Application in Developing an α-Glucosidase-Specific Inhibitor

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Hye-Jeong Choi ◽  
Dam-Seul Ko ◽  
Na-Ri Kim ◽  
Woo-Jae Choung ◽  
Ye-Seul Koo ◽  
...  
Keyword(s):  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
High Yield ◽  
Glycoside Hydrolase Family ◽  
Potential Candidate ◽  
Inhibitory Effects ◽  
Bacteroides Thetaiotaomicron ◽  
Amino Acid Sequence Alignment ◽  
Prevention Of Diabetes ◽  
Hydrolase Family

In this study, α-glucanotransferase from Bacteroides thetaiotaomicron was expressed in Escherichia coli and characterized. Conserved amino-acid sequence alignment showed that Bacteroides thetaiotaomicron α-glucanotransferase (BtαGTase) belongs to the glycoside hydrolase family 77. The enzyme exhibited optimal catalytic activity at 60°C and pH 3.0. BtαGTase catalyzed transglycosylation reactions that produced only glycosyl or maltosyl transfer products, which are preferable for the generation of transglycosylated products with high yield. The 1-deoxynojirimycin (DNJ) glycosylation product G1-DNJ was generated using BtαGTase, and the inhibitory effect of G1-DNJ was analyzed. A kinetic study of inhibition revealed that G1-DNJ inhibited α-glucosidase to a greater extent than did DNJ but did not show any inhibitory effects towards α-amylase, suggesting that G1-DNJ is a potential candidate for the prevention of diabetes.

scholarly journals A novel glycoside hydrolase family 97 enzyme: Bifunctional β- l -arabinopyranosidase/α-galactosidase from Bacteroides thetaiotaomicron

Biochimie ◽  
2017 ◽  
Vol 142 ◽  
pp. 41-50 ◽  
Author(s):  
Asako Kikuchi ◽  
Masayuki Okuyama ◽  
Koji Kato ◽  
Shohei Osaki ◽  
Min Ma ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Glycoside Hydrolase Family ◽  
Bacteroides Thetaiotaomicron ◽  
Hydrolase Family

scholarly journals Ginsenoside Rh1 Prevents Migration and Invasion through Mitochondrial ROS-Mediated Inhibition of STAT3/NF-κB Signaling in MDA-MB-231 Cells

2021 ◽  
Vol 22 (19) ◽  
pp. 10458
Author(s):  
Yujin Jin ◽  
Diem Thi Ngoc Huynh ◽  
Chang-Seon Myung ◽  
Kyung-Sun Heo
Keyword(s):  
Breast Cancer ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Migration And Invasion ◽  
Ros Generation ◽  
Mrna Levels ◽  
Inhibitory Effects ◽  
Mitochondrial Ros ◽  
Stat3 Phosphorylation ◽  
High Level

Breast cancer (BC) a very common cancer in women worldwide. Triple negative breast cancer (TNBC) has been shown to have a poor prognosis with a high level of tumor metastatic spread. Here, the inhibitory effects of ginsenoside-Rh1 (Rh1) on BC metastasis, and its underlying signaling pathway in TNBC were investigated. Rh1-treated MDA-MB-231 cells were analyzed for metastasis using a wound healing assay, transwell migration and invasion assay, western blotting, and qRT-PCR. Rh1 treatment significantly inhibited BC metastasis by inhibiting the both protein and mRNA levels of MMP2, MMP9, and VEGF-A. Further, Rh1-mediated inhibitory effect on BC migration was associated with mitochondrial ROS generation. Rh1 treatment significantly eliminated STAT3 phosphorylation and NF-κB transactivation to downregulate metastatic factors, such as MMP2, MMP9, and VEGF-A. In addition, Mito-TEMPO treatment reversed Rh1 effects on the activation of STAT3, NF-κB, and their transcriptional targets. Rh1 further enhanced the inhibitory effects of STAT3 or NF-κB specific inhibitor, stattic or BAY 11-7082 on MMP2, MMP9, and VEGF-A expression, respectively. In summary, our results revealed the potent anticancer effect of Rh1 on TNBC migration and invasion through mtROS-mediated inhibition of STAT3 and NF-κB signaling.

Biochemical characterization and mechanism of action of a thermostable β-glucosidase purified from Thermoascus aurantiacus

2000 ◽  
Vol 353 (1) ◽  
pp. 117-127 ◽  
Author(s):  
Neil J. PARRY ◽  
David E. BEEVER ◽  
Emyr OWEN ◽  
Isabel VANDENBERGHE ◽  
Jozef VAN BEEUMEN ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Glycoside Hydrolase Family ◽  
Thermoascus Aurantiacus ◽  
Amino Acid Sequence Alignment ◽  
Cellobiose Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Terminal Amino ◽  
High Concentrations ◽  
Hydroxy Groups ◽  
Hydrolase Family

An extracellular β-glucosidase from Thermoascus aurantiacus was purified to homogeneity by DEAE-Sepharose, Ultrogel AcA 44 and Mono-P column chromatography. The enzyme was a homotrimer, with a monomer molecular mass of 120kDa; only the trimer was optimally active at 80°C and at pH 4.5. At 90°C, the enzyme showed 70% of its optimal activity. It was stable at pH 5.2 and at temperatures up to 70°C for 48h, but stability decreased above 70°C and at pH values above and below 5.0. The enzyme hydrolysed aryl and alkyl β-d-glucosides and cello-oligosaccharides, and was specific for substrates with a β-glycosidic linkage. The hydroxy groups at positions 2, 4 and 6 of a glucose residue at the non-reducing end of a disaccharide appeared to be essential for catalysis. The enzyme had the lowest Km towards p-nitrophenyl β-d-glucoside (0.1137mM) and the highest kcat towards cellobiose and β,β-trehalose (17052min-1). It released one glucose unit at a time from the non-reducing end of cello-oligosaccharides, and the rate of hydrolysis decreased with an increase in chain length. Glucose and d-δ-gluconolactone inhibited the β-glucosidase competitively, with Ki values of 0.29mM and 8.3nM respectively, while methanol, ethanol and propan-2-ol activated the enzyme. The enzyme catalysed the synthesis of methyl, ethyl and propyl β-d-glucosides in the presence of methanol, ethanol and propan-2-ol respectively with either glucose or cellobiose, although cellobiose was preferred. An acidic pH favoured hydrolysis and transglycosylation, but high concentrations of alcohols favoured the latter reaction. The stereochemistry of cellobiose hydrolysis revealed that β-glucosidase from T. aurantiacus is a retaining glycosidase, while N-terminal amino acid sequence alignment indicated that it is a member of glycoside hydrolase family 3.

scholarly journals TK-PUL, a pullulan hydrolase type III from Thermococcus kodakarensis, a potential candidate for simultaneous liquefaction and saccharification of starch

Amylase ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 45-55
Author(s):  
Khurram Jahangir Toor ◽  
Nasir Ahmad ◽  
Majida Atta Muhammad ◽  
Naeem Rashid
Keyword(s):  
Corn Starch ◽  
Specific Activity ◽  
Glycoside Hydrolase Family ◽  
Potential Candidate ◽  
Fed Batch ◽  
Thermococcus Kodakarensis ◽  
Fed Batch Culture ◽  
Starch Industry ◽  
Hydrolase Family ◽  
Single Enzyme

AbstractTK-PUL, a novel thermo-acidophilic pullulanase from Thermococcus kodakarensis and a unique member of glycoside hydrolase family GH13 was successfully produced in Escherichia coli grown by fed batch culture in a fermenter and partially purified by simple heat treatment. Specific activity of partially purified TK-PUL was 28 U/mg. Corn starch was successfully liquefied and saccharified using this single enzyme at pH 4.2. Simultaneous liquefaction and saccharification of corn starch by TK-PUL was comparable to Termamyl, a commercially available starch-hydrolyzing industrial enzyme. Both enzymes efficiently hydrolysed corn starch into sugar syrups having major proportions of maltose. TK-PUL performs efficiently at the natural pH of starch (~4.5) in the absence of any metal ions, hence is a potential candidate for starch industry.

scholarly journals Measuring Responses of Dicyandiamide-, 3,4-Dimethylpyrazole Phosphate-, and Allylthiourea-Induced Nitrification Inhibition to Soil Abiotic and Biotic Factors

2021 ◽  
Vol 18 (13) ◽  
pp. 7130
Author(s):  
Yu-Pin Lin ◽  
Andrianto Ansari ◽  
Lien-Chieh Cheng ◽  
Chiao-Ming Lin ◽  
Rainer-Ferdinand Wunderlich ◽  
...  
Keyword(s):  
Soil Texture ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Application Rate ◽  
Nitrification Inhibitors ◽  
Biotic Factors ◽  
Inhibitory Effects ◽  
Temperature Conditions ◽  
Abiotic And Biotic Factors ◽  
Study Laboratory

Nitrification inhibitors (NIs) such as dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP), and allylthiourea (AT) are commonly used to suppress ammonia oxidization at different time scales varying from a few hours to several months. Although the responses of NIs to edaphic and temperature conditions have been studied, the influence of the aforementioned factors on their inhibitory effect remains unknown. In this study, laboratory-scale experiments were conducted to assess the short-term (24 h) influence of eight abiotic and biotic factors on the inhibitory effects of DCD, DMPP, and AT across six cropped and non-cropped soils at two temperature conditions with three covariates of soil texture. Simultaneously, the dominant contributions of ammonia-oxidizing archaea (AOA) and bacteria (AOB) to potential ammonia oxidization (PAO) were distinguished using the specific inhibitor 2 phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Our results revealed that AT demonstrated a considerably greater inhibitory effect (up to 94.9% for an application rate of 75 mg of NI/kg of dry soil) than DCD and DMPP. The inhibitory effect of AT was considerably affected by the relative proportions of silt, sand, and clay in the soil and total PAO. In contrast to previous studies, the inhibitory effects of all three NIs remained largely unaffected by the landcover type and temperature conditions for the incubation period of 24 h. Furthermore, the efficacy of all three tested NIs was not affected by the differential contributions of AOA and AOB to PAO. Collectively, our results suggested a limited influence of temperature on the inhibitory effects of all three NIs but a moderate dependence of AT on the soil texture and PAO. Our findings can enhance the estimation of the inhibitory effect in soil, and pure cultures targeting the AOA and AOB supported ammonia oxidization and, hence, nitrogen dynamics under NI applications.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Inhibition of ADP-Induced Responses in Human Platelets by Agents Elevating the Cyclic AMP Level: Comparison of Aggregation and Shape Change

1984 ◽  
Vol 52 (03) ◽  
pp. 333-335 ◽  
Author(s):  
Vider M Steen ◽  
Holm Holmsen
Keyword(s):  
Inhibitory Action ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Inhibitory Effects ◽  
Early Step ◽  
Stimulus Response ◽  
Sequential Relationship

SummaryThe inhibitory effect of cAMP-elevating agents on shape change and aggregation in human platelets was studied to improve the understanding of the sequential relationship between these two responses.Human platelet-rich plasma was preincubated for 2 min at 37° C with prostaglandin E1 or adenosine, agents known to elevate the intracellular level of cAMP. Their inhibitory effects on ADP-induced shape change and aggregation were determined both separately and simultaneously. The dose-inhibition patterns for shape change and aggregation were similar for both PGE1 and adenosine. There was no distinct difference between the inhibitory action of these two inhibitors.These observations suggest that elevation of the intracellular concentration of cAMP interferes with an early step in the stimulus-response coupling that is common for aggregation and shape change.

The Inhibitory Effect of Heparin and Related Glycosaminoglycans on Neutrophil Chemotaxis

1984 ◽  
Vol 52 (02) ◽  
pp. 134-137 ◽  
Author(s):  
Yaacov Matzner ◽  
Gerard Marx ◽  
Ruth Drexler ◽  
Amiram Eldor
Keyword(s):  
Specific Binding ◽  
Anticoagulant Activity ◽  
Neutrophil Migration ◽  
Inhibitory Effect ◽  
Chemotactic Factor ◽  
Human Neutrophils ◽  
Boyden Chamber ◽  
Neutrophil Chemotaxis ◽  
Inhibitory Effects ◽  
Chemotactic Factors

SummaryClinical observations have shown that heparin has antiinflammatory activities. The effect of heparin on neutrophil chemotaxis was evaluated in vitro in the Boyden Chamber. This method enabled differentiation between the direct effects of heparin on neutrophil migration and locomotion, and its effects on chemotactic factors. Heparin inhibited both the random migration and directed locomotion of human neutrophils toward zymosan-activated serum (ZAS) and F-met-leu-phe (FMLP). Inhibition was found to be dependent on the concentrations of the heparin and of the chemotactic factors. No specific binding of heparin to the neutrophils could be demonstrated, and heparin’s inhibitory effects were eliminated by simple washing of the cells. When added directly to the chamber containing chemotactic factor, heparin inhibited the chemotactic activity of ZAS but not that of FMLP, suggesting a direct inhibitory effect against C5a, the principal chemotactic factor in ZAS.Experiments performed with low-molecular-weight heparin, N-desulfated heparin, dextran sulfate, chondroitin sulfate and dextran indicated that the inhibitory effects of heparin on neutrophil chemotaxis are not related to its anticoagulant activity, but probably depend on the degree of sulfation of the heparin molecule.

Inhibition of Yeast Growth by Tryptamine and Recovery with Tryptophan

2020 ◽  
Vol 16 (1) ◽  
pp. 48-52 ◽  
Author(s):  
Chandrika Kadkol ◽  
Ian Macreadie
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Competitive Inhibition ◽  
Yeast Species ◽  
Inhibitory Effect ◽  
The Body ◽  
Inhibitory Effects ◽  
Trna Synthetases ◽  
Fermentative Growth ◽  
Biogenic Monoamine

Background: Tryptamine, a biogenic monoamine that is present in trace levels in the mammalian central nervous system, has probable roles as a neurotransmitter and/or a neuromodulator and may be associated with various neuropsychiatric disorders. One of the ways tryptamine may affect the body is by the competitive inhibition of the attachment of tryptophan to tryptophanyl tRNA synthetases. Methods: This study has explored the effects of tryptamine on growth of six yeast species (Saccharomyces cerevisiae, Candida glabrata, C. krusei, C. dubliniensis, C. tropicalis and C. lusitaniae) in media with glucose or ethanol as the carbon source, as well as recovery of growth inhibition by the addition of tryptophan. Results: Tryptamine was found to have an inhibitory effect on respiratory growth of all yeast species when grown with ethanol as the carbon source. Tryptamine also inhibited fermentative growth of Saccharomyces cerevisiae, C. krusei and C. tropicalis with glucose as the carbon source. In most cases the inhibitory effects were reduced by added tryptophan. Conclusion: The results obtained in this study are consistent with tryptamine competing with tryptophan to bind mitochondrial and cytoplasmic tryptophanyl tRNA synthetases in yeast: effects on mitochondrial and cytoplasmic protein synthesis can be studied as a function of growth with glucose or ethanol as a carbon source. Of the yeast species tested, there is variation in the sensitivity to tryptamine and the rescue by tryptophan. The current study suggests appropriate yeast strains and approaches for further studies.

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