Selection and analysis of mutants of the CO2-concentrating mechanism in cyanobacteria

1991 ◽  
Vol 69 (5) ◽  
pp. 974-983 ◽  
Author(s):  
Murray R. Badger ◽  
G. Dean Price ◽  
Jian Wei Yu
Keyword(s):  
Current Knowledge ◽  
In Vitro Assays ◽  
Key Words Cyanobacteria ◽  
Mutant Selection ◽  
Genetic Components ◽  
Concentrating Mechanism ◽  
Physiological Analysis ◽  
Inorganic Carbon Transport ◽  
Further Development

The selection and analysis of mutants of the CO2-concentrating mechanism in cyanobacteria have greatly advanced our understanding of the physiological and genetic components of this mechanism. This paper reviews the processes for the creation of mutants and the properties of mutants that have been produced so far. In addition to this, consideration is given to developing new mutant selection protocols, based on our current knowledge of the operation of the CO2-concentrating mechanism. As a result, new screens are suggested for the isolation of transport mutants that are defective in either HCO3− or CO2 transport activity, and putative carboxysomal mutants that have altered carbonic anhydrase activities. The procedures for physiological analysis of mutants are also reviewed, with a conclusion that there is a great need for the further development of in vitro assays, particularly for the inorganic carbon transport process and carboxysome function. Particular consideration is given to the in vitro carboxysome assay, and it is concluded that many of the properties of a carboxysomal Rubisco may be difficult to resolve owing to increases in carboxysomal leakiness during isolation and the higher ratio of [CO2] to [HCO3−] experienced during assays compared with the in vitro situation. Finally, consideration is given to the genetic analysis of cyanobacterial mutants and the progress that will need to be made in the future, discovering what are the functions of the proteins coded for by the genes that are isolated. Key words: cyanobacteria, mutants, photosynthesis, carboxysome, CO2-concentrating mechanism.

scholarly journals Anti-Tick-Borne Encephalitis Virus Activity of Novel Uridine Glycoconjugates Containing Amide or/and 1,2,3-Triazole Moiety in the Linker Structure

2020 ◽  
Vol 13 (12) ◽  
pp. 460
Author(s):  
Gabriela Brzuska ◽  
Gabriela Pastuch-Gawolek ◽  
Monika Krawczyk ◽  
Boguslaw Szewczyk ◽  
Ewelina Krol
Keyword(s):  
Antiviral Treatment ◽  
Encephalitis Virus ◽  
In Vitro Assays ◽  
Strong Activity ◽  
Tick Borne Encephalitis ◽  
Ic50 Values ◽  
Low Cytotoxicity ◽  
Tick Borne Encephalitis Virus ◽  
Further Development

Tick-borne encephalitis virus (TBEV) transmitted by ticks is a pathogen of great medical importance. As still no effective antiviral treatment is available, in the present study, a series of uridine glycoconjugates containing amide or/and 1,2,3-triazole moiety in the linker structure was synthesized and evaluated for the antiviral activity against two strains of TBEV: a highly virulent Hypr strain and less virulent Neudoerfl strain, using standardized previously in vitro assays. Our data have shown that four compounds from the series (18–21) possess strong activity against both TBEV strains. The half maximal inhibitory concentration (IC50) values of compounds 18–21 were between 15.1 and 3.7 μM depending on the virus strain, which along with low cytotoxicity resulted in high values of the selectivity index (SI). The obtained results suggest that these compounds may be promising candidates for further development of new therapies against flaviviruses.

scholarly journals Chicken Egg Proteins and Derived Peptides with Antioxidant Properties

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 735 ◽  
Author(s):  
Sara Benedé ◽  
Elena Molina
Keyword(s):  
Current Knowledge ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Reducing Power ◽  
In Vitro Assays ◽  
Main Process ◽  
Processing Technologies ◽  
Chicken Egg

In addition to their high nutritional value, some chicken egg proteins and derivatives such as protein hydrolysates, peptides and amino acids show antioxidant properties which make them prominent candidates for the development of functional foods, drawing attention to both the food and biopharmaceutical industries. This review summarizes current knowledge on antioxidant activity of chicken egg proteins and their derived peptides. Some egg proteins such as ovalbumin, ovotransferrin and lysozyme from egg white or phosvitin from yolk have shown antioxidant properties, although derived peptides have higher bioactive potential. The main process for obtaining egg bioactive peptides is enzymatic hydrolysis of its proteins using enzymes and/or processing technologies such as heating, sonication or high-intensity-pulsed electric field. Different in vitro assays such as determination of reducing power, DPPH and ABTS radical-scavenging activity tests or oxygen radical absorbance capacity assay have been used to evaluate the diverse antioxidant mechanisms of proteins and peptides. Similarly, different cell lines and animal models including zebrafish, mice and rats have also been used. In summary, this review collects all the knowledge described so far regarding egg proteins and derived peptides with antioxidant functions.

Challenges in translational research on probiotic lactobacilli: from in vitro assays to clinical trials

2013 ◽  
Vol 4 (1) ◽  
pp. 83-100 ◽  
Author(s):  
M. Meijerink ◽  
A. Mercenier ◽  
J.M. Wells
Keyword(s):  
Translational Research ◽  
Selection Criteria ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Intestinal Barrier ◽  
Probiotic Strain ◽  
In Vitro Assays ◽  
Intestinal Barrier Function

Beneficial effects of certain probiotic strains have been established in the treatment and prevention of various immune and intestinal disorders in humans, including allergic diseases, chronic inflammatory diseases and diarrhoea. The proposed mechanisms underlying the immunomodulatory effects of probiotics in humans are not understood in precise detail but include enhancement of intestinal barrier function, altered epithelial signalling, competition with pathogens and effects on immune cells and immunity depending on the probiotic strain. The publication of controversial or inconclusive probiotic studies in humans highlights the need for a better understanding of the mechanisms and improved strain selection criteria. This review focuses on the immunomodulatory properties of lactobacilli and bifidobacteria in vitro and in vivo, current knowledge concerning the mechanisms in vivo and challenges in translational research on probiotics. A better understanding of the molecular mechanisms of probiotics, the effect of probiotic mixtures versus single strains, the effect of formulation of probiotics and the fate of ingested probiotics should help to clarify the value of immune assays as selection criteria for probiotics.

scholarly journals Development and Evaluation of a Human Skin Equivalent in a Semiautomatic Microfluidic Diffusion Chamber

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 910
Author(s):  
Júlia Tárnoki-Zách ◽  
Elod Mehes ◽  
Zsófia Varga-Medveczky ◽  
Dona Greta Isai ◽  
Nandor Barany ◽  
...  
Keyword(s):  
Diffusion Chamber ◽  
Skin Equivalent ◽  
In Vitro Assays ◽  
High Concentration ◽  
Cosmetic Ingredients ◽  
Increasing Demand ◽  
Penetration Profile ◽  
Further Development ◽  
Transdermal Transport

There is an increasing demand for transdermal transport measurements to optimize topical drug formulations and to achieve proper penetration profile of cosmetic ingredients. Reflecting ethical concerns the use of both human and animal tissues is becoming more restricted. Therefore, the focus of dermal research is shifting towards in vitro assays. In the current proof-of-concept study a three-layer skin equivalent using human HaCaT keratinocytes, an electrospun polycaprolactone mesh and a collagen-I gel was compared to human excised skin samples. We measured the permeability of the samples for 2% caffeine cream using a miniaturized dynamic diffusion cell (“skin-on-a-chip” microfluidic device). Caffeine delivery exhibits similar transport kinetics through the artificial skin and the human tissue: after a rapid rise, a long-lasting high concentration steady state develops. This is markedly distinct from the kinetics measured when using cell-free constructs, where a shorter release was observable. These results imply that both the established skin equivalent and the microfluidic diffusion chamber can serve as a suitable base for further development of more complex tissue substitutes.

scholarly journals Sub-Inhibitory Antibiotic Exposure and Virulence in Pseudomonas aeruginosa

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1393
Author(s):  
Charlotte Nolan ◽  
Volker Behrends
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factor ◽  
Current Knowledge ◽  
In Vitro Assays ◽  
Antibiotic Exposure ◽  
Bacterial Physiology ◽  
Factor Expression ◽  
The Impact

Pseudomonas aeruginosa is a prime opportunistic pathogen, one of the most important causes of hospital-acquired infections and the major cause of morbidity and mortality in cystic fibrosis lung infections. One reason for the bacterium’s pathogenic success is the large array of virulence factors that it can employ. Another is its high degree of intrinsic and acquired resistance to antibiotics. In this review, we first summarise the current knowledge about the regulation of virulence factor expression and production. We then look at the impact of sub-MIC antibiotic exposure and find that the virulence–antibiotic interaction for P. aeruginosa is antibiotic-specific, multifaceted, and complex. Most studies undertaken to date have been in vitro assays in batch culture systems, involving short-term (<24 h) antibiotic exposure. Therefore, we discuss the importance of long-term, in vivo-mimicking models for future work, particularly highlighting the need to account for bacterial physiology, which by extension governs both virulence factor expression and antibiotic tolerance/resistance.

IN VITRO ASSAYS OF ADENYL CYCLASE

1971 ◽  
Vol 68 (1_Suppl) ◽  
pp. S337-S347 ◽  
Author(s):  
Martin Rodbell
Keyword(s):  
Protein Kinases ◽  
Cyclic Nucleotide ◽  
Current Knowledge ◽  
Adenyl Cyclase ◽  
In Vitro Assays ◽  
Animal Cells ◽  
Intact Cells ◽  
Dependent Protein

ABSTRACT A brief review of the properties and current knowledge of the components of adenyl cyclase systems in animal cells is presented, followed by some general remarks on the problems of assaying adenyl cyclase. Recent techniques developed for the assay of adenyl cyclase in broken cell preparations are described. Methods which determine the levels of cyclic 3′5′AMP in intact cells or tissues are also presented, with particular emphasis on the use of binding of the nucleotide to cyclic 3′5′AMP dependent protein kinases and radioimmunoassays of the cyclic nucleotide.

A in Vivo Assay for Standardizing Heparin Preparations

1979 ◽  
Vol 41 (03) ◽  
pp. 576-582
Author(s):  
A R Pomeroy
Keyword(s):  
In Vitro Assays ◽  
British Pharmacopoeia ◽  
In Vitro Method ◽  
Standard Preparation ◽  
Reliable Estimation ◽  
Assay Procedure ◽  
Accuracy And Precision ◽  
Heparin Preparation

SummaryThe limitations of currently used in vitro assays of heparin have demonstrated the need for an in vivo method suitable for routine use.The in vivo method which is described in this paper uses, for each heparin preparation, four groups of five mice which are injected intravenously with heparin according to a “2 and 2 dose assay” procedure. The method is relatively rapid, requiring 3 to 4 hours to test five heparin preparations against a standard preparation of heparin. Levels of accuracy and precision acceptable for the requirements of the British Pharmacopoeia are obtained by combining the results of 3 to 4 assays of a heparin preparation.The similarity of results obtained the in vivo method and the in vitro method of the British Pharmacopoeia for heparin preparations of lung and mucosal origin validates this in vivo method and, conversely, demonstrates that the in vitro method of the British Pharmacopoeia gives a reliable estimation of the in vivo activity of heparin.

Potentially Thrombogenic Materials in Factor IX Concentrates

1975 ◽  
Vol 33 (03) ◽  
pp. 617-631 ◽  
Author(s):  
H. S Kingdon ◽  
R. L Lundblad ◽  
J. J Veltkamp ◽  
D. L Aronson
Keyword(s):  
Human Plasma ◽  
Antithrombin Iii ◽  
Factor Ix ◽  
In Vitro Assays ◽  
Substantial Agreement ◽  
Coefficient Of Correlation

SummaryFactor IX concentrates manufactured from human plasma and intended for therapeutic infusion in man have been suspected for some time of being potentially thrombogenic. In the current studies, assays were carried out in vitro and in vivo for potentially thrombogenic materials. It was possible to rank the various materials tested according to the amount of thrombogenic material detected. For concentrates not containing heparin, there was substantial agreement between the in vivo and in vitro assays, with a coefficient of correlation of 0.77. There was no correlation between the assays for thrombogenicity and the antithrombin III content. We conclude that many presently available concentrates of Factor IX contain substantial amounts of potentially thrombogenic enzymes, and that this fact must be considered in arriving at the decision whether or not to use them therapeutically.

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.

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