Reuse of Lipase from Pseudomonas fluorescens via Its Step-by-Step Coimmobilization on Glyoxyl-Octyl Agarose Beads with Least Stable Lipases

Coimmobilization of lipases may be interesting in many uses, but this means that the stability of the least stable enzyme determines the stability of the full combilipase. Here, we propose a strategy that permits the reuse the most stable enzyme. Lecitase Ultra (LU) (a phospholipase) and the lipases from Rhizomucor miehei (RML) and from Pseudomonas fluorescens (PFL) were immobilized on octyl agarose, and their stabilities were studied under a broad range of conditions. Immobilized PFL was found to be the most stable enzyme under all condition ranges studied. Furthermore, in many cases it maintained full activity, while the other enzymes lost more than 50% of their initial activity. To coimmobilize these enzymes without discarding fully active PFL when LU or RML had been inactivated, PFL was covalently immobilized on glyoxyl-agarose beads. After biocatalysts reduction, the other enzyme was coimmobilized just by interfacial activation. After checking that glyoxyl-octyl-PFL was stable in 4% Triton X-100, the biocatalysts of PFL coimmobilized with LU or RML were submitted to inactivation under different conditions. Then, the inactivated least stable coimmobilized enzyme was desorbed (using 4% detergent) and a new enzyme reloading (using in some instances RML and in some others employing LU) was performed. The initial activity of immobilized PFL was maintained intact for several of these cycles. This shows the great potential of this lipase coimmobilization strategy.

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Multi-Combilipases: Co-Immobilizing Lipases with Very Different Stabilities Combining Immobilization via Interfacial Activation and Ion Exchange. The Reuse of the Most Stable Co-Immobilized Enzymes after Inactivation of the Least Stable Ones

Catalysts ◽

10.3390/catal10101207 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1207

Author(s):

Sara Arana-Peña ◽

Diego Carballares ◽

Vicente Cortés Corberan ◽

Roberto Fernandez-Lafuente

Keyword(s):

Ammonium Sulfate ◽

Rhizomucor Miehei ◽

Immobilized Enzymes ◽

The Other ◽

Thermomyces Lanuginosus ◽

Vinyl Sulfone ◽

Interfacial Activation ◽

Agarose Beads ◽

Immobilized Biocatalyst ◽

Lecitase Ultra

The lipases A and B from Candida antarctica (CALA and CALB), Thermomyces lanuginosus (TLL) or Rhizomucor miehei (RML), and the commercial and artificial phospholipase Lecitase ultra (LEU) may be co-immobilized on octyl agarose beads. However, LEU and RML became almost fully inactivated under conditions where CALA, CALB and TLL retained full activity. This means that, to have a five components co-immobilized combi-lipase, we should discard 3 fully active and immobilized enzymes when the other two enzymes are inactivated. To solve this situation, CALA, CALB and TLL have been co-immobilized on octyl-vinyl sulfone agarose beads, coated with polyethylenimine (PEI) and the least stable enzymes, RML and LEU have been co-immobilized over these immobilized enzymes. The coating with PEI is even favorable for the activity of the immobilized enzymes. It was checked that RML and LEU could be released from the enzyme-PEI coated biocatalyst, although this also produced some release of the PEI. That way, a protocol was developed to co-immobilize the five enzymes, in a way that the most stable could be reused after the inactivation of the least stable ones. After RML and LEU inactivation, the combi-biocatalysts were incubated in 0.5 M of ammonium sulfate to release the inactivated enzymes, incubated again with PEI and a new RML and LEU batch could be immobilized, maintaining the activity of the three most stable enzymes for at least five cycles of incubation at pH 7.0 and 60 °C for 3 h, incubation on ammonium sulfate, incubation in PEI and co-immobilization of new enzymes. The effect of the order of co-immobilization of the different enzymes on the co-immobilized biocatalyst activity was also investigated using different substrates, finding that when the most active enzyme versus one substrate was immobilized first (nearer to the surface of the particle), the activity was higher than when this enzyme was co-immobilized last (nearer to the particle core).

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Effect of Concentrated Salts Solutions on the Stability of Immobilized Enzymes: Influence of Inactivation Conditions and Immobilization Protocol

Molecules ◽

10.3390/molecules26040968 ◽

2021 ◽

Vol 26 (4) ◽

pp. 968

Author(s):

Sabrina Ait Braham ◽

El-Hocine Siar ◽

Sara Arana-Peña ◽

Diego Carballares ◽

Roberto Morellon-Sterling ◽

...

Keyword(s):

Immobilized Enzyme ◽

Enzyme Stability ◽

Immobilized Enzymes ◽

Penicillin G ◽

Specific Enzyme ◽

Interfacial Activation ◽

Agarose Beads ◽

High Concentrations ◽

The Stability ◽

Universal Rule

This paper aims to investigate the effects of some salts (NaCl, (NH4)2SO4 and Na2SO4) at pH 5.0, 7.0 and 9.0 on the stability of 13 different immobilized enzymes: five lipases, three proteases, two glycosidases, and one laccase, penicillin G acylase and catalase. The enzymes were immobilized to prevent their aggregation. Lipases were immobilized via interfacial activation on octyl agarose or on glutaraldehyde-amino agarose beads, proteases on glyoxyl agarose or glutaraldehyde-amino agarose beads. The use of high concentrations of salts usually has some effects on enzyme stability, but the intensity and nature of these effects depends on the inactivation pH, nature and concentration of the salt, enzyme and immobilization protocol. The same salt can be a stabilizing or a destabilizing agent for a specific enzyme depending on its concentration, inactivation pH and immobilization protocol. Using lipases, (NH4)2SO4 generally permits the highest stabilities (although this is not a universal rule), but using the other enzymes this salt is in many instances a destabilizing agent. At pH 9.0, it is more likely to find a salt destabilizing effect than at pH 7.0. Results confirm the difficulty of foreseeing the effect of high concentrations of salts in a specific immobilized enzyme.

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Creatine kinase in serum: 5. Effect of thiols on isoenzyme activity during storage at various temperatures.

Clinical Chemistry ◽

10.1093/clinchem/24.9.1557 ◽

1978 ◽

Vol 24 (9) ◽

pp. 1557-1563 ◽

Cited By ~ 22

Author(s):

G Szasz ◽

W Gerhardt ◽

W Gruber

Keyword(s):

Creatine Kinase ◽

The Other ◽

Initial Activity ◽

Creatine Kinase Isoenzymes ◽

Acetyl Cysteine ◽

The Stability

Abstract We studied changes in the activity of human creatine kinase isoenzymes (native MM in serum, MM, MB, and BB preparations in serum matrix) on storage in the presence of 0, 10, 20, and 50 mmol of N-acetyl cysteine, 2-mercaptoethanol, and 1-thioglycerol per liter of serum at 37, 30, 25, 4, and -20 degrees C. We also assessed the stability of the thiols under the same conditions. We generally confirmed increasing stability in the sequence: BB, MB, and MM isoenzyme. Above 30 degrees C irreversible inactivation is very rapid, even in the presence of thiols. At lower temperatures endogenous MM is sufficiently stable; thus, the use of protective thiols can be restricted to sera expected to contain isoenzymes MB or BB. Our studies lead us to prefer use of 50 mmol of N-acetyl cysteine per liter of serum. The other thiols cause turbidity to develop earlier and their decomposittion products diminish the activity more. The initial activity of the MB and BB preparations increased by as much as 2.3- and 1.8-fold on storage with thiols. This effect was not observed with either endogenous MB and MM or with the MM prepartion.

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Uniformity of Magnification from Different Electron Microscopes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060179 ◽

1967 ◽

Vol 25 ◽

pp. 32-33

Author(s):

Godfrey C. Hoskins ◽

V. Williams ◽

V. Allison

Keyword(s):

Diffraction Grating ◽

The Other ◽

Carbon Replica ◽

Electron Microscopes ◽

The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

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Black Hole Algorithm for Sustainable Design of Counterfort Retaining Walls

Sustainability ◽

10.3390/su12072767 ◽

2020 ◽

Vol 12 (7) ◽

pp. 2767 ◽

Cited By ~ 13

Author(s):

Víctor Yepes ◽

José V. Martí ◽

José García

Keyword(s):

Black Hole ◽

Sustainable Design ◽

Retaining Walls ◽

The Other ◽

Trade Off ◽

Construction Company ◽

Geometric Variables ◽

The Stability ◽

The Cost ◽

Black Hole Algorithm

The optimization of the cost and CO 2 emissions in earth-retaining walls is of relevance, since these structures are often used in civil engineering. The optimization of costs is essential for the competitiveness of the construction company, and the optimization of emissions is relevant in the environmental impact of construction. To address the optimization, black hole metaheuristics were used, along with a discretization mechanism based on min–max normalization. The stability of the algorithm was evaluated with respect to the solutions obtained; the steel and concrete values obtained in both optimizations were analyzed. Additionally, the geometric variables of the structure were compared. Finally, the results obtained were compared with another algorithm that solved the problem. The results show that there is a trade-off between the use of steel and concrete. The solutions that minimize CO 2 emissions prefer the use of concrete instead of those that optimize the cost. On the other hand, when comparing the geometric variables, it is seen that most remain similar in both optimizations except for the distance between buttresses. When comparing with another algorithm, the results show a good performance in optimization using the black hole algorithm.

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A Fractional SAIDR Model in the Frame of Atangana–Baleanu Derivative

Fractal and Fractional ◽

10.3390/fractalfract5020032 ◽

2021 ◽

Vol 5 (2) ◽

pp. 32

Author(s):

Esmehan Uçar ◽

Sümeyra Uçar ◽

Fırat Evirgen ◽

Necati Özdemir

Keyword(s):

Existence And Uniqueness ◽

Laplace Transformation ◽

Cell Phones ◽

Mobile Network ◽

The Other ◽

Banach Fixed Point Theorem ◽

Propagation Models ◽

Computer Worms ◽

Computer Viruses ◽

The Stability

It is possible to produce mobile phone worms, which are computer viruses with the ability to command the running of cell phones by taking advantage of their flaws, to be transmitted from one device to the other with increasing numbers. In our day, one of the services to gain currency for circulating these malignant worms is SMS. The distinctions of computers from mobile devices render the existing propagation models of computer worms unable to start operating instantaneously in the mobile network, and this is particularly valid for the SMS framework. The susceptible–affected–infectious–suspended–recovered model with a classical derivative (abbreviated as SAIDR) was coined by Xiao et al., (2017) in order to correctly estimate the spread of worms by means of SMS. This study is the first to implement an Atangana–Baleanu (AB) derivative in association with the fractional SAIDR model, depending upon the SAIDR model. The existence and uniqueness of the drinking model solutions together with the stability analysis are shown through the Banach fixed point theorem. The special solution of the model is investigated using the Laplace transformation and then we present a set of numeric graphics by varying the fractional-order θ with the intention of showing the effectiveness of the fractional derivative.

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Competing Conventions with Costly Information Acquisition

Games ◽

10.3390/g12030053 ◽

2021 ◽

Vol 12 (3) ◽

pp. 53

Author(s):

Roberto Rozzi

Keyword(s):

Information Acquisition ◽

Evolutionary Model ◽

Equilibrium Selection ◽

The Other ◽

Group Interactions ◽

Social Coordination ◽

Long Run ◽

Stochastic Stability Analysis ◽

The Stability ◽

The Cost

We consider an evolutionary model of social coordination in a 2 × 2 game where two groups of players prefer to coordinate on different actions. Players can pay a cost to learn their opponent’s group: if they pay it, they can condition their actions concerning the groups. We assess the stability of outcomes in the long run using stochastic stability analysis. We find that three elements matter for the equilibrium selection: the group size, the strength of preferences, and the information’s cost. If the cost is too high, players never learn the group of their opponents in the long run. If one group is stronger in preferences for its favorite action than the other, or its size is sufficiently large compared to the other group, every player plays that group’s favorite action. If both groups are strong enough in preferences, or if none of the groups’ sizes is large enough, players play their favorite actions and miscoordinate in inter-group interactions. Lower levels of the cost favor coordination. Indeed, when the cost is low, in inside-group interactions, players always coordinate on their favorite action, while in inter-group interactions, they coordinate on the favorite action of the group that is stronger in preferences or large enough.

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Calmodulin-microtubule association in cultured mammalian cells.

The Journal of Cell Biology ◽

10.1083/jcb.98.3.904 ◽

1984 ◽

Vol 98 (3) ◽

pp. 904-910 ◽

Cited By ~ 51

Author(s):

W J Deery ◽

A R Means ◽

B R Brinkley

Keyword(s):

Plasma Membrane ◽

Mammalian Cells ◽

Cell System ◽

The Other ◽

Microtubule Assembly ◽

Cytoplasmic Microtubule ◽

Hypotonic Treatment ◽

Cytoplasmic Microtubules ◽

Triton X ◽

Ca Sensitivity

A Triton X-100-lysed cell system has been used to identify calmodulin on the cytoskeleton of 3T3 and transformed SV3T3 cells. By indirect immunofluorescence, calmodulin was found to be associated with both the cytoplasmic microtubule complex and the centrosomes. A number of cytoplasmic microtubules more resistant to disassembly upon either cold (0-4 degrees C) or hypotonic treatment, as well as following dilution have been identified. Most of the stable microtubules appeared to be associated with the centrosome at one end and with the plasma membrane at the other end. These microtubules could be induced to depolymerize, however, by micromolar Ca++ concentrations. These data suggest that, by interacting directly with the microtubule, calmodulin may influence microtubule assembly and ensure the Ca++-sensitivity of both mitotic and cytoplasmic microtubules.

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A Biomechanical Evaluation of Three Forms of Internal Fixation Used in Ankle Arthrodesis

Foot & Ankle International ◽

10.1177/107110079401500603 ◽

1994 ◽

Vol 15 (6) ◽

pp. 297-300 ◽

Cited By ~ 45

Author(s):

Michael P. Dohm ◽

James B. Benjamin ◽

Jeffrey Harrison ◽

John A. Szivek

Keyword(s):

Internal Fixation ◽

Plate Fixation ◽

Ankle Arthrodesis ◽

Biomechanical Study ◽

The Other ◽

Fixation Failure ◽

Plate Group ◽

Biomechanical Evaluation ◽

The Stability ◽

Fibular Strut

A biomechanical study was undertaken to evaluate the relative stability of three types of internal fixation used for ankle arthrodesis. Crossed screw fixation, RAF fibular strut fixation, and T-plate fixation were tested in 30 cadaver ankles using an MTS machine. T-plate fixation consistantly provided the stiffest construct when compared with the other types of fixation. Failure occurred by distraction of bony surfaces, posterior to the plane of fixation, in the crossed screw and RAF groups. In contrast, failure in the T-plate group occurred through compression of bone anterior to the midcoronal plane of the tibia. Although the stability of fixation is only one factor in determining the success or failure of ankle arthrodesis, the results of this study would support T-plate fixation over the other forms tested.

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Tetracycline Induces Stabilization of mRNA in Bacillus subtilis

Journal of Bacteriology ◽

10.1128/jb.184.4.889-894.2002 ◽

2002 ◽

Vol 184 (4) ◽

pp. 889-894 ◽

Cited By ~ 21

Author(s):

Yi Wei ◽

David H. Bechhofer

Keyword(s):

Bacillus Subtilis ◽

Mrna Stability ◽

The Other ◽

Leader Region ◽

Subinhibitory Concentration ◽

Coding Sequence ◽

Mrna Stabilization ◽

Threefold Increase ◽

The Stability

ABSTRACT The tet(L) gene of Bacillus subtilis confers low-level tetracycline (Tc) resistance. Previous work examining the >20-fold-inducible expression of tet(L) by Tc demonstrated a 12-fold translational induction. Here we show that the other component of tet(L) induction is at the level of mRNA stabilization. Addition of a subinhibitory concentration of Tc results in a two- to threefold increase in tet(L) mRNA stability. Using a plasmid-borne derivative of tet(L) with a large in-frame deletion of the coding sequence, the mechanism of Tc-induced stability was explored by measuring the decay of tet(L) mRNAs carrying specific mutations in the leader region. The results of these experiments, as well as experiments with a B. subtilis strain that is resistant to Tc due to a mutation in the ribosomal S10 protein, suggest different mechanisms for the effects of Tc on translation and on mRNA stability. The key role of the 5" end in determining mRNA stability was confirmed in these experiments. Surprisingly, the stability of several other B. subtilis mRNAs was also induced by Tc, which indicates that addition of Tc may result in a general stabilization of mRNA.

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