Effect of prostaglandin E1-induced elevation of cyclic AMP on glucose repression in the lactic streptococci

1980 ◽  
Vol 26 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Timothy L. Ratliff ◽  
Robert S. Stinson ◽  
Dwight E. Talburt
Keyword(s):  
Glucose Repression ◽  
Streptococcus Thermophilus ◽  
Adenyl Cyclase ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Prostaglandin E ◽  
Intracellular Camp ◽  
Streptococcus Lactis

Cyclic adenosine 3′,5′-monophosphate (cAMP) activity was observed in Streptococcus lactis C2, Streptococcus cremoris C10, Streptococcus diacetlactis 18-16, and Streptococcus thermophilus C3. In vitro assays of cell-free extracts obtained from S. lactis C2 showed that the cAMP-associated enzymes adenyl cyclase and phosphodiesterase were also present. In vitro experiments showed that prostaglandin E1 (PGE) stimulation of adenyl cyclase increased cAMP concentrations approximately fivefold, and in vivo studies showed that PGE treatment of S. lactis C2 increased intracellular cAMP concentrations twofold. Furthermore, PGE-induced elevation of intracellular cAMP levels was shown to prevent the repression of β-D-phosphogalactoside galactohydrolase synthesis by glucose.

In-silico Studies of Isolated Phytoalkaloid Against Lipoxygenase: Study Based on Possible Correlation

2018 ◽  
Vol 21 (3) ◽  
pp. 215-221
Author(s):  
Haroon Khan ◽  
Muhammad Zafar ◽  
Helena Den-Haan ◽  
Horacio Perez-Sanchez ◽  
Mohammad Amjad Kamal
Keyword(s):  
In Silico ◽  
Docking Studies ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Chronic Obstructive ◽  
Lipoxygenase Inhibitors ◽  
Lipoxygenase Inhibition ◽  
In Silico Studies

Aim and Objective: Lipoxygenase (LOX) enzymes play an important role in the pathophysiology of several inflammatory and allergic diseases including bronchial asthma, allergic rhinitis, atopic dermatitis, allergic conjunctivitis, rheumatoid arthritis and chronic obstructive pulmonary disease. Inhibitors of the LOX are believed to be an ideal approach in the treatment of diseases caused by its over-expression. In this regard, several synthetic and natural agents are under investigation worldwide. Alkaloids are the most thoroughly investigated class of natural compounds with outstanding past in clinically useful drugs. In this article, we have discussed various alkaloids of plant origin that have already shown lipoxygenase inhibition in-vitro with possible correlation in in silico studies. Materials and Methods: Molecular docking studies were performed using MOE (Molecular Operating Environment) software. Among the ten reported LOX alkaloids inhibitors, derived from plant, compounds 4, 2, 3 and 1 showed excellent docking scores and receptor sensitivity. Result and Conclusion: These compounds already exhibited in vitro lipoxygenase inhibition and the MOE results strongly correlated with the experimental results. On the basis of these in vitro assays and computer aided results, we suggest that these compounds need further detail in vivo studies and clinical trial for the discovery of new more effective and safe lipoxygenase inhibitors. In conclusion, these results might be useful in the design of new and potential lipoxygenase (LOX) inhibitors.

scholarly journals TGFβ signalling acts as a molecular brake of myoblast fusion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Julie Melendez ◽  
Daniel Sieiro ◽  
David Salgado ◽  
Valérie Morin ◽  
Marie-Julie Dejardin ◽  
...  
Keyword(s):  
Dynamic Control ◽  
Muscle Growth ◽  
Myoblast Fusion ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Receptor Complex ◽  
Tgfβ Signalling ◽  
Molecular Brake

AbstractFusion of nascent myoblasts to pre-existing myofibres is critical for skeletal muscle growth and repair. The vast majority of molecules known to regulate myoblast fusion are necessary in this process. Here, we uncover, through high-throughput in vitro assays and in vivo studies in the chicken embryo, that TGFβ (SMAD2/3-dependent) signalling acts specifically and uniquely as a molecular brake on muscle fusion. While constitutive activation of the pathway arrests fusion, its inhibition leads to a striking over-fusion phenotype. This dynamic control of TGFβ signalling in the embryonic muscle relies on a receptor complementation mechanism, prompted by the merging of myoblasts with myofibres, each carrying one component of the heterodimer receptor complex. The competence of myofibres to fuse is likely restored through endocytic degradation of activated receptors. Altogether, this study shows that muscle fusion relies on TGFβ signalling to regulate its pace.

STUDIES ON THE ANTICOAGULANT AND ANTITHROMBOTIC ACTIONS OF DERMATANS AND THEIR SULFATED DERIVATIVES

1987 ◽  
Author(s):  
D Hoppensteadt ◽  
A Kumar ◽  
J Fareed ◽  
J Mardigian
Keyword(s):  
Antithrombin Iii ◽  
Femoral Vein ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Protease Inhibition ◽  
Thrombosis Model ◽  
Antithrombotic Effects ◽  
Activated Prothrombin Complex Concentrates

Non-antithrombin III mediated effects such as interaction with heparin cofactor II, modulation of endothelium and polymorphonuclear leukocytes contribute to the overall antithrombotic effects of glycosaminoglycans. In order to study the role of these dermatans, we investigated their in vitro anticoagulant effects using the clot based (PT, APTT, TT, and Heptest), antiprotease (anti IIa and anti Xa) and Thromboplastin C activated fibrinopeptide A generation test. The in vivo antithrombotic actions were investigated, against activated and non activated prothrombin complex concentrates, and in combination with Russells viper venom in jugular and femoral vein stasis thrombosis models (rabbit). The dermatans studied consisted of a standard dermatan of porcine intestinal origin and four sulfated dermatans with varying degrees of sulfation. All of the dermatans studied showed weak anticoagulant effects on the routinely performed clot based assays. Marked variability was seen on the protease inhibition (anti Xa and anti IIa) assays. In the in vivo studies all dermatans studied showed varying degrees of antithrombotic actions against various thrombogenic agents in a modified stasis thrombosis model. Sulfation appeared to produce stronger anticoagulant effects as determined by in vitro assays, whereas the intravenous antithrombotic actions of native dermatan were stronger than sulfated derivatives. This data suggests that dermatans produce their antithrombotic actions via non-antithrombin III mediated pathways. Furthermore, in vitro testing methods are of limited value in the evaluation of the biologic actions of dermatans and their derivatives.

Can in vitro assays substitute for in vivo studies in assessing the pulmonary hazards of fine and nanoscale materials?

2008 ◽  
Vol 11 (2) ◽  
pp. 421-431 ◽  
Author(s):  
Christie M. Sayes ◽  
Kenneth L. Reed ◽  
Shekhar Subramoney ◽  
Lloyd Abrams ◽  
David B. Warheit
Keyword(s):  
In Vivo Studies ◽  
In Vitro Assays ◽  
Nanoscale Materials

Angiotensin II formation in dog heart is mediated by different pathways in vivo and in vitro

1996 ◽  
Vol 271 (2) ◽  
pp. H417-H421 ◽  
Author(s):  
E. Balcells ◽  
Q. C. Meng ◽  
G. R. Hageman ◽  
R. W. Palmer ◽  
J. N. Durand ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Heart Tissue ◽  
Left Ventricular ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Ang Ii ◽  
Dog Heart ◽  
Tissue Extracts

Angiotensin-converting enzyme (ACE) inhibitors (I) have beneficial effects that are presumably mediated by decreased angiotensin II (ANG II) production. However, in vitro assays in human heart extracts have demonstrated that > 75% of ANG II-forming enzyme activity was not inhibited by captopril (Cap) and therefore did not appear to be related to ACE but was inhibited by chymostatin, suggesting that it was predominantly chymase-like activity. Previous work in our laboratory has demonstrated a similar relative contribution of ACE and chymase-like activity toward ANG II formation in vitro in dog heart tissue extracts. Accordingly, we compared Cap-inhibitable ANG II formation in vitro in heart tissue of five adult mongrel dogs to the in vivo Cap-inhibitable, ANG II-forming activity across the myocardial bed in four openchest, adult mongrel dogs. In vitro studies demonstrated that only 6 +/- 2% of ANG II formation was inhibited by Cap from heart tissue extracts of the left ventricular midwall. In in vivo studies, ANG I (0.5 nmol/min) followed by ANG I plus the ACE inhibitor Cap (0.1 mumol/min) was infused into the left anterior descending artery, and ANG II was assayed in the proximal aorta and coronary sinus. The arterial-venous (A-V) difference of ANG II across the myocardial circulation increased significantly during ANG I infusion (-13.4 +/- 23.5 to 142.8 +/- 71.4 pg/ml; P < 0.03). Subsequent coinfusion of Cap with ANG I significantly decreased the myocardial A-V difference of ANG II by 60 +/- 18% (P < 0.05). Thus, in contrast to the in vitro situation, ANG II formation in vivo is inhibited significantly by Cap in the normal dog heart. This comparison of in vivo and in vitro conversion of ANG I to ANG II by ACE and chymase-like activity suggests that in vitro assays may underestimate the functional contribution of ACE to intracardiac ANG II formation.

scholarly journals Small-Molecule Inhibitors of the Rce1p CaaX Protease

2007 ◽  
Vol 12 (7) ◽  
pp. 983-993 ◽  
Author(s):  
Surya P. Manandhar ◽  
Emily R. Hildebrandt ◽  
Walter K. Schmidt
Keyword(s):  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Proteolytic Processing ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Selective Agents ◽  
Wild Type Yeast ◽  
Micromolar Range

The Rce1p protease is required for the maturation of the Ras GTPase and certain other isoprenylated proteins and is considered a chemotherapeutic target. To identify new small-molecule inhibitors of Rce1p, the authors screened the National Cancer Institute Diversity Set compound library using in vitro assays to monitor the proteolytic processing of peptides derived from Ras and the yeast a-factor mating pheromone. Of 46 inhibitors initially identified with a Ras-based assay, only 9 were effective in the pheromone-based assay. The IC50 values of these 9 compounds were in the low micromolar range for both yeast (6-35 µM) and human Rce1p (0.4-46 µM). Four compounds were somewhat Rce1p selective in that they partially inhibited the Ste24p protease and did not inhibit Ste14p isoprenylcysteine carboxyl methyltransferase, 2 enzymes also involved in the maturation of isoprenylated proteins. The remaining 5 compounds inhibited all 3 enzymes. The 2 most Rce1p-selective agents were ineffective trypsin inhibitors, further supporting the specificity of these agents for Rce1p. The 5 least specific compounds formed colloidal aggregates, a proposed common feature of promiscuous inhibitors. Interestingly, the most specific Rce1p inhibitor also formed a colloidal aggregate. In vivo studies revealed that treatment of wild-type yeast with 1 compound induced a Ras2p delocalization phenotype that mimics observed effects in rce1 ste24 null yeast. The 9 compounds identified in this study represent new tools for understanding the enzymology of postisoprenylation-modifying enzymes and provide new insight for the future development of Rce1p inhibitors. ( Journal of Biomolecular Screening 2007:983-993)

scholarly journals MODL-29. EVALUATING TUMOR-IMMUNE INTERACTIONS IN MOUSE MODELS OF DIFFUSE INTRINSIC PONTINE GLIOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii417-iii417
Author(s):  
Robin Furnish ◽  
Heather Bear ◽  
Xin Wei ◽  
Timothy Phoenix
Keyword(s):  
Mouse Models ◽  
Diffuse Intrinsic Pontine Glioma ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Preclinical Studies ◽  
Check Point ◽  
Pontine Glioma ◽  
Therapeutic Benefits

Abstract BACKGROUND While adult gliomas show some level of immune cell infiltration, diffuse intrinsic pontine glioma (DIPG) is characterized as having an “immune cold” state. We have developed new immunocompetent mouse models of DIPG. These models faithfully recapitulate the pathological hallmarks of DIPG and provides a unique platform to investigate immune modulatory therapies and potential therapeutic benefits of check point inhibitor combination therapies. METHODS To evaluate the effects of CDK4/6 inhibition (CDK4/6i) on cell proliferation and immune interactions we performed a series of in vitro and in vivo studies using DIPG mouse models. In vitro assays included dose response curves, transcriptional profiling, and MHC1 expression. In vivo preclinical studies treated mouse models with CDK4/6i with or without immune check-point inhibitors (ICI). We also examined other candidate immune modulatory therapies in vitro. RESULTS CDK4/6i (Abemeciclib) reduced proliferation of DIPG cells derived from mouse models, and displayed a modest increase in immune activation by MHC1 expression and transcriptome. Pilot in vivo preclinical studies did not show any significant changes in DIPG proliferation or immune changes with CDK4/6i treatment, ICI treatment, or the combination of CDK4/6i + ICI. In vitro testing of other immune-modulatory drugs identified additional candidates that can be tested in vivo. CONCLUSION CDK4/6i displayed in vitro action, but lacked efficacy in DIPG mouse models in vivo. Further use of spontaneous DIPG mouse models will provide a rapid preclinical platform to evaluate in vivo tumor-immune interactions, drug efficacy, and mechanisms of resistance.

Natural Products as Potential Agents Against SARS-CoV and SARS-CoV-2

2021 ◽  
Vol 28 ◽  
Author(s):  
Joanda Paolla Raimundo e Silva ◽  
Chonny Alexander Herrera Acevedo ◽  
Thalisson Amorim de Souza ◽  
Renata Priscila Barros de Menezes ◽  
Zoe L. Sessions ◽  
...  
Keyword(s):  
Natural Products ◽  
In Silico ◽  
Principal Component ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Future Research ◽  
Natural Substances ◽  
Effective Drugs

Background: Natural products are useful agents for the discovery of new lead-compounds and effective drugs to combat coronaviruses (CoV). Objective: The present work provides an overview of natural substances, plant extracts, and essential oils as potential antiSARS-CoV agents. In addition, this work evaluates their drug-like properties which are essential in the selection of compounds in order to accelerate the drug development process. Methods: The search was carried out using PubMed, ScienceDirect and SciFinder. Articles addressing plant-based natural products as potential SARS-CoV or SARS-CoV-2 agents within the last seventeen years were analyzed and selected. The descriptors for Chemometrics analyzes were obtained in alvaDesc and the principal component analyzes (PCA) were carried out in SIMCA version 13.0. Results: Based on in vitro assays and computational analyzes, this review covers twenty nine medicinal plant species and more than 300 isolated substances as potential anti-coronavirus agents. Among them, flavonoids and terpenes were the most promising compound classes. In silico analyses of drug-like properties corroborate these findings and indicate promising candidates for in vitro and in vivo studies to validate their activity. Conclusion: This paper highlights the role of ethnopharmacology in drug discovery and simulates the use of integrative (in silico/ in vitro) and chemocentric approaches to strengthen current studies and guide future research in the field of antivirals agents.

scholarly journals In vitro action of Mimosa caesalpinifolia ketone extract on Haemonchus contortus and Trichostrongylus colubriformis

2017 ◽  
Vol 38 (4) ◽  
pp. 1963 ◽  
Author(s):  
Danilo Rodrigues Barros Brito ◽  
Livio Martins Costa Júnior ◽  
João Luis Garcia ◽  
Suzana Gomes Lopes ◽  
Giselle Cutrim de Oliveira Santos ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Haemonchus Contortus ◽  
Anthelmintic Activity ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Trichostrongylus Colubriformis ◽  
Lower Efficiency ◽  
Egg Hatchability

This study aimed to evaluate the in vitro anthelmintic activity of Mimosa caesalpinifolia (sabiá) ketone extract, which is rich in condensed tannins (CT), on Haemonchus contortus and Trichostrongylus colubriformis. The leaves and stems of M. caesalpinifolia were collected, dried in the shade, and ground to a dry powder from which ketone extracts were obtained for in vitro assays. The extracts were diluted in 5% acetone and PBS to concentrations in the range 0.25-2.80 mg mL-¹ and the inhibition of egg hatchability was assayed. Feces collected from goats naturally infected with H. contortus (55%) and T. colubriformis (45%) were macerated and the helminth eggs were collected to conduct in vitro egg hatchability tests. Nematode larvae collected from the feces were used for a larval exsheathment inhibition assay of M. caesalpinifolia leaf and M. caesalpinifolia leaf and stem ketone extracts at concentrations of 0.6 and 1.2 mg mL-¹; three replicates were performed for each concentration. PBS was used as a negative control. Polyvinylpolypyrrolidone (PVPP) was added to the extracts to assess the effect of phenolic compounds on anthelmintic activity. An inhibitory effect of 80.7% and 82.3% was observed on hatchability after treatment with 1.0 and 2.0 mg mL-¹ M. caesalpinifolia leaf ketone extract, respectively. An inhibition rate lower than 75% was observed for 1.0 mg mL-¹ M. caesalpinifolia leaf and stem ketone extract. The M. caesalpinifolia leaf ketone extract larval exsheathment assay resulted in inhibition of 97.3% and 99.8% at concentrations of 0.6 and 1.2 mg mL-¹, respectively. For the leaf and stem ketone extract, the larval exsheathment inhibition was 94.3% at 1.2 mg mL-¹. The leaf and leaf and stem extracts showed no inhibitory effects on larval exsheathment after the addition of PVPP. These results showed that cuticular loss was related to the action of the phenolic compounds in the M. caesalpinifolia extracts. M. caesalpinifolia leaf ketone extract inhibited egg hatchability, but the leaf and stem extract showed lower efficiency, which indicated a greater abundance of active compounds in the leaves. The M. caesalpinifolia ketone extracts were effective in the inhibition of larval exsheathment at the highest concentration tested. Based on these results, in vivo studies should be performed to demonstrate the anthelmintic activity of this plant in goats.

scholarly journals Phytochemical analysis, in-vitro anti-proliferative, anti-oxidant, anti-diabetic, and anti-obesity activities of Rumex rothschildianus Aarons. extracts

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nidal Jaradat ◽  
Mohammed Hawash ◽  
Gada Dass
Keyword(s):  
Chemical Constituents ◽  
Cancer Cell Line ◽  
Positive Control ◽  
Hexane Fraction ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Phytochemical Analysis ◽  
Mcf7 Cells

Abstract Background Rumex rothschildianus is the sole member of a unique section of the genus Rumex, in the family Polygonaceae. This species is a very rare small dioecious annual, endemic to Palestine that is traditionally used as food and for the treatment of various diseases. Therefore, the current investigation aimed to screen the chemical constituents, antioxidants, anti-α-amylase, anti-α-glucosidase, antilipase, and cytotoxic effects of four solvents fractions of R. rothschildianus leaves. Methods Dried powder of R. rothschildianus leaves was extracted in four solvents with different polarities. Several qualitative and quantitative phytochemical tests were performed to determine the components of the extracts. The colorimetric analysis was used for the quantitative determination of phenols, flavonoids, and tannins. In-vitro assays were performed to evaluate the extracts for antioxidant, anti-α-amylase, anti-α-glucosidase, and antilipase inhibitory activities, as well as cytotoxicity by MTS assay against cervical carcinoma cells line (HeLa) and breast cancer cell line (MCF7). Results The acetone fraction of R. rothschildianus leaves showed the most significant antioxidant activity, due to having the highest content of flavonoids and phenolics, with an IC50 value of 6.3 ± 0.4 μg/ml, compared to 3.1 ± 0.9 μg/ml for Trolox, and regarding lipase inhibition activity the acetone fraction showed the most potent activity with an IC50 value of 26.3 ± 0.6 μg/ml, in comparison with orlistat positive control IC50 12.3 μg/ml. The same extract was the most potent inhibitor of α-amylase and α-glucosidase, with IC50 values of 19.1 ± 0.7 μg/ml and 54.9 ± 0.3 μg/ml, respectively, compared to 28.8, 37.1 ± 0.3 μg/ml of acarbose, respectively. The hexane fraction showed 99.9% inhibition of HeLa cells and 97.4% inhibition for MCF7 cells. Conclusion The acetone fraction of R. rothschildianus leaves might provide a source of bioactive compounds for the treatment of oxidative stress. Similarly, the hexane fraction indicates the promising antitumor potential of R. rothschildianus. Clearly, these initial indications need further purification of potentially active compounds, and ultimately, in-vivo studies to determine their effectiveness.

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