scholarly journals Extremophilic SHMTs: From Structure to Biotechnology

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Sebastiana Angelaccio
Keyword(s):  
Structural Changes ◽  
Extreme Environments ◽  
Industrial Applications ◽  
Enzyme Engineering ◽  
Suitable Model ◽  
Functional Studies ◽  
Metabolic Role ◽  
Enzyme Adaptation ◽  
High And Low Temperatures ◽  
Data Banks

Recent advances in molecular and structural biology have improved the availability of virtually any biocatalyst in large quantity and have also provided an insight into the detailed structure-function relationships of many of them. These results allowed the rational exploitation of biocatalysts for use in organic synthesis. In this context, extremophilic enzymes are extensively studied for their potential interest for many biotechnological and industrial applications, as they offer increased rates of reactions, higher substrate solubility, and/or longer enzyme half-lives at the conditions of industrial processes. Serine hydroxymethyltransferase (SHMT), for its ubiquitous nature, represents a suitable model for analyzing enzyme adaptation to extreme environments. In fact, many SHMT sequences from Eukarya, Eubacteria and Archaea are available in data banks as well as several crystal structures. In addition, SHMT is structurally conserved because of its critical metabolic role; consequently, very few structural changes have occurred during evolution. Our research group analyzed the molecular basis of SHMT adaptation to high and low temperatures, using experimental and comparativein silicoapproaches. These structural and functional studies of SHMTs purified from extremophilic organisms can help to understand the peculiarities of the enzyme activity at extreme temperatures, indicating possible strategies for rational enzyme engineering.

Enzyme engineering and its industrial applications

2021 ◽  
Author(s):  
Isabela Victorino da Silva Amatto ◽  
Nathalia Gonsales da Rosa‐Garzon ◽  
Flávio Antônio de Oliveira Simões ◽  
Fernanda Santiago ◽  
Nathália Pereira da Silva Leite ◽  
...  
Keyword(s):  
Industrial Applications ◽  
Enzyme Engineering

Abstract P604: Astrocyte-dependent Regulation of Vascular Tone: Role in Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Juan Manuel Ramiro-Diaz ◽  
Ki Jung Kim ◽  
Jessica A Filosa
Keyword(s):  
Vascular Tone ◽  
Structural Changes ◽  
Neurovascular Unit ◽  
Brain Slices ◽  
Vascular Cognitive Impairment ◽  
Vascular Density ◽  
Aqp4 Expression ◽  
Functional Changes ◽  
Functional Studies ◽  
Underlying Mechanisms

Clinical studies support that untreated hypertension (HT) accelerates the development of vascular cognitive impairment (VCI). Yet, the underlying mechanisms for VCI are not known. In a recent study we demonstrated the role of astrocytes in the regulation of parenchymal arteriole (PA) steady-state vascular tone. Here we hypothesized hypertension results in structural and functional changes to the neurovascular unit resulting in enhanced astrocytic TRPV4 channel-dependent Ca 2+ increases contributing to augmented pressure-induced PA constriction . Functional studies were conducted in brain slices from angiotensin II (AngII) treated mice (600 ng/Kg/min, 28 days). PA arterioles within brain slices were perfused and pressurized and myogenic-evoked diameter changes measured using video microscopy. In addition, using the GLAST-CreERT2 ; R26-lsl-GCaMP3 mice we measure myogenic-evoked Ca 2+ changes in perivascular astrocytes. We demonstrate that HT increases pressure-induced PA tone by 11.14% at 30 mmHg and 12.97% at 60 mmHg (10.88 to 22.02 and 15.46 to 28.43% of tone, P<0.05 and P<0.01, respectively). In ANG II-treated mice, PA myogenic-evoked responses significantly increased astrocytic Ca 2+ oscillations frequency (119.4%, 0.0366 to 0.0803 Hz, P<0.0001). A significant increase in astrocytic Ca 2+ oscillation frequency was also observed after 2 min of AngII (500 nM) bath application (44.8%, 0.0366 to 0.053 Hz, P<0.01) in brain slices from AngII treated mice. Furthermore, using the model of spontaneous hypertensive rat (SHR) we observed that HT differentially increases vascular density and the number of vascular pericytes in cortical layers with highest neuronal densities (L III-V). Finally, while aquaporin 4 (AQP4) expression pattern was not different in the gray matter of SHR compared with WKY rats, a significant increase in unpolarized AQP4 expression was observed in the white matter of SHR. Taken together, this evidence indicates that HT induces functional and structural changes to the neurovascular unit favoring the development of regional brain hypoperfusion likely contributing to the development of VCI.

Vascular Ca overload produced by vitamin D3 plus nicotine diminishes arterial distensibility in rats

1994 ◽  
Vol 266 (2) ◽  
pp. H540-H547 ◽  
Author(s):  
J. Atkinson ◽  
P. Poitevin ◽  
J. M. Chillon ◽  
I. Lartaud ◽  
B. Levy
Keyword(s):  
Vitamin D3 ◽  
Structural Changes ◽  
Arterial Compliance ◽  
Linear Regression Analysis ◽  
Characteristic Impedance ◽  
Calcium Overload ◽  
Suitable Model ◽  
Plasma Parameters ◽  
Arterial Distensibility ◽  
Young Rats

In humans, aging produces many structural changes in blood vessels, one of the most pronounced being arterial calcium overload. Simultaneously arteries become increasingly rigid. The slow evolution of the two processes renders it difficult to evaluate the importance of vascular calcium overload in the development of decreased compliance. To gain insight into this relationship, rapid vascular calcium overload was produced by treating young rats with vitamin D3 and nicotine. When rats were allowed 16 days or longer to recover from such treatment, analysis of plasma parameters revealed no overt toxicity, and growth rate was similar to that of controls. Pronounced calcium overload was seen primarily in compliance arteries. Changes in systemic arterial compliance, characteristic impedance, pulse-wave velocity, and carotid compliance all reflected a substantial increase in arterial rigidity. Linear regression analysis revealed significant correlations between the various indicators of arterial distensibility and arterial calcium content. In conclusion, treatment of young rats with vitamin D3 and nicotine may provide a suitable model with which to investigate how calcium overload is involved in the induration of compliance arteries.

A Thermal Model for Laser Hardening Simulation

2015 ◽  
Author(s):  
Erica Liverani ◽  
Alessandro Fortunato ◽  
Alessandro Ascari ◽  
Donato Sorgente ◽  
Leonardo Daniele Scintilla ◽  
...  
Keyword(s):  
Process Model ◽  
Computation Time ◽  
Setup Time ◽  
Industrial Applications ◽  
Carbon Steels ◽  
Laser Hardening ◽  
Suitable Model ◽  
Unknown Parameters ◽  
Thermally Induced ◽  
Medium Carbon Steels

Laser hardening is a very flexible and useful process for surface treatment of medium carbon steels, capable of processing varied and complex geometries. In order to enlarge the range of industrial applications to which this process can be applied, a suitable model is necessary in order to reduce the setup time requested for the optimization of new components. The process model presented is based on the Arrhenius-like equation for estimation of the thermally induced process reaction time for microstructural transformations. By means of experiments, all unknown parameters in the equations have been determined, highlighting the accuracy and low computation time of the simulator.

scholarly journals Structure-based enzyme engineering improves donor-substrate recognition of Arabidopsis thaliana glycosyltransferases

2020 ◽  
Vol 477 (15) ◽  
pp. 2791-2805
Author(s):  
Aishat Akere ◽  
Serena H. Chen ◽  
Xiaohan Liu ◽  
Yanger Chen ◽  
Sarath Chandra Dantu ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Biochemical Characterization ◽  
Structural Information ◽  
Substrate Recognition ◽  
Industrial Applications ◽  
Enzyme Engineering ◽  
Donor Substrate ◽  
Substrate Preferences ◽  
Dynamics Simulations ◽  
Experimental Crystal

Glycosylation of secondary metabolites involves plant UDP-dependent glycosyltransferases (UGTs). UGTs have shown promise as catalysts in the synthesis of glycosides for medical treatment. However, limited understanding at the molecular level due to insufficient biochemical and structural information has hindered potential applications of most of these UGTs. In the absence of experimental crystal structures, we employed advanced molecular modeling and simulations in conjunction with biochemical characterization to design a workflow to study five Group H Arabidopsis thaliana (76E1, 76E2, 76E4, 76E5, 76D1) UGTs. Based on our rational structural manipulation and analysis, we identified key amino acids (P129 in 76D1; D374 in 76E2; K275 in 76E4), which when mutated improved donor substrate recognition than wildtype UGTs. Molecular dynamics simulations and deep learning analysis identified structural differences, which drive substrate preferences. The design of these UGTs with broader substrate specificity may play important role in biotechnological and industrial applications. These findings can also serve as basis to study other plant UGTs and thereby advancing UGT enzyme engineering.

scholarly journals Spontaneous formation of multilayer refractory carbide coatings in a molten salt media

2021 ◽  
Vol 118 (18) ◽  
pp. e2100663118
Author(s):  
Loic Constantin ◽  
Lisha Fan ◽  
Mathilde Pouey ◽  
Jérôme Roger ◽  
Bai Cui ◽  
...  
Keyword(s):  
Molten Salt ◽  
Multilayer Coating ◽  
Extreme Environments ◽  
Extreme Temperature ◽  
Industrial Applications ◽  
Great Promise ◽  
Refractory Carbide ◽  
High Quality ◽  
Refractory Coating ◽  
Carbide Coatings

Refractory materials hold great promise to develop functional multilayer coating for extreme environments and temperature applications but require high temperature and complex synthesis to overcome their strong atomic bonding and form a multilayer structure. Here, a spontaneous reaction producing sophisticated multilayer refractory carbide coatings on carbon fiber (CF) is reported. This approach utilizes a relatively low-temperature (950 °C) molten-salt process for forming refractory carbides. The reaction of titanium (Ti), chromium (Cr), and CF yields a complex, high-quality multilayer carbide coating composed of 1) Cr carbide (Cr3C2), 2) Ti carbide, and 3) Cr3C2 layers. The layered sequence arises from a difference in metal dissolutions, reactions, and diffusion rates in the salt media. The multilayer-coated CFs act as a permeable oxidation barrier with no crystalline degradation of the CFs after extreme temperature (1,200 °C) and environment (oxyacetylene flame) exposure. The synthesis of high-quality multilayer refractory coating in a fast, efficient, easy, and clean manner may answer the need for industrial applications that develop cheap and reliable extreme environment protection barriers.

scholarly journals Analysis of Structural Changes in Jute Fibers after Peracetic Acid Treatment

2017 ◽  
Vol 12 (1) ◽  
pp. 155892501701200 ◽  
Author(s):  
Ling Duan ◽  
Weidong Yu ◽  
Zhaoling Li
Keyword(s):  
Peracetic Acid ◽  
Textile Industry ◽  
Structural Changes ◽  
Treatment Time ◽  
Cellulose Fibers ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Jute Fibers ◽  
Structure Changes ◽  
C Nmr

Peracetic acid (PAA) is one of the most commonly used bleaching agents in the textile industry. The structural changes of jute fibers after PAA treatment are important in creating industrial applications. An investigation was carried out to determine the structural changes resulting from the removal of noncellulosic materials from jute fibers by PAA. The surface features of jute fiber were studied using a scanning electron microscope. PAA was effective in separateingindividual cellulose fibers from raw jute. However, fibers were damaged when the treatment time reached 80 minutes, PAA concentration was 10 wt. % and the pH was in the 4~5 range. The delignification by PAA treatment was confirmed by Fourier transform infrared spectroscopy. CP/MAS 13C-NMR spectroscopy showed that the PAA did cause some macromolecular structure changes in the cellulose fibers. X-ray diffraction technique demonstrated that there were four stages of crystallinity change, due to the removal of noncellulosic materials. These four stages include attack at the surfaces of cellulose crystallites, the dissolution of amorphous zones, attack of the inner cellulose crystallite and oxygen interference, respectively.

scholarly journals Parametric optimization of Edm on Hastelloy C-276 Using Taguchi L18 Technique

2018 ◽  
Vol 7 (2.7) ◽  
pp. 714 ◽  
Author(s):  
SK Khadar Basha ◽  
Murahari Kolli ◽  
M V.Jagannadha Raju
Keyword(s):  
Process Parameters ◽  
Discharge Current ◽  
Removal Rate ◽  
Extreme Environments ◽  
Industrial Applications ◽  
Dielectric Fluid ◽  
Machining Performance ◽  
Current Electrode ◽  
Pulse On Time ◽  
Pulse Off Time

Due to development in machining science the use of composites and alloys is a great deal for every industry. Hastelloy C276 the most versatile corrosion resistant nickel based super alloy which is used for industrial applications is considered for doing the            experiments .The high nickel and molybdenum content provides better corrosion resistance at extreme environments. In this report, the experiments are performed by using Taguchi L18 technique and their results are used for performance of each process parameters on their output responses. The process parameters considered for experimentation are discharge current, pulse- on- time, type of electrode and pulse off time for the output responses of material removal rate and surface roughness. Eco-friendly (drinking water) is used as a dielectric fluid. The experiments are designed and conducted using Taguchi L18 technique and analyze the influence of each process parameters on machining performance characteristics. Further, mathematical equations were developed using the statistical software MINITAB17.0.ANOVA is used for analyzing the experimental results obtained. It was observed from the response table that the average values of MRR and SR for pulse on time, discharge current, electrode are identified as important process parameters.  

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