Stability and Folding of the Unusually Stable Hemoglobin from Synechocystis is Subtly Optimized and Dependent on the Key Heme Pocket Residues.

2020 ◽  
Vol 27 ◽  
Author(s):  
Sheetal Uppal ◽  
Mohd. Asim Khan ◽  
Suman Kundu
Keyword(s):  
Molten Globule ◽  
Life Forms ◽  
Model System ◽  
Heme Pocket ◽  
The Past ◽  
Specific Manner ◽  
Delivery Vehicles ◽  
The Stability ◽  
Key Residues ◽  
Synechocystis Sp

Aims: The aim of our study is to understand the biophysical traits that govern the stability and folding of Synechocystis hemoglobin, a unique cyanobacterial globin that displays unusual traits not observed in any of the other globins discovered so far. Background: For the past few decades, classical hemoglobins such as vertebrate hemoglobin and myoglobin have been extensively studied to unravel the stability and folding mechanisms of hemoglobins. However, the expanding wealth of hemoglobins identified in all life forms with novel properties, like heme coordination chemistry and globin fold, have added complexity and challenges to the understanding of hemoglobin stability, which has not been adequately addressed. Here, we explored the unique truncated and hexacoordinate hemoglobin from the freshwater cyanobacterium Synechocystis sp. PCC 6803 known as “Synechocystis hemoglobin (SynHb)”. The “three histidines” linkages to heme are novel to this cyanobacterial hemoglobin. Objective: Mutational studies were employed to decipher the residues within the heme pocket that dictate the stability and folding of SynHb. Methods: Site-directed mutants of SynHb were generated and analyzed using a repertoire of spectroscopic and calorimetric tools. Result: The results revealed that the heme was stably associated to the protein under all denaturing conditions with His117 playing the anchoring role. The studies also highlighted the possibility of existence of a “molten globule” like intermediate at acidic pH in this exceptionally thermostable globin. His117 and other key residues in the heme pocket play an indispensable role in imparting significant polypeptide stability. Conclusion: Synechocystis hemoglobin presents an important model system for investigations of protein folding and stability in general. The heme pocket residues influenced the folding and stability of SynHb in a very subtle and specific manner and may have been optimized to make this Hb the most stable known as of date. Other: The knowledge gained hereby about the influence of heme pocket amino acid side chains on stability and expression is currently being utilized to improve the stability of recombinant human Hbs for efficient use as oxygen delivery vehicles.

scholarly journals Dynamical study of infochemical influences on tropic interaction of diffusive plankton system

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Satish Kumar Tiwari ◽  
Ravikant Singh ◽  
Nilesh Kumar Thakur
Keyword(s):  
Dimethyl Sulfide ◽  
Algal Bloom ◽  
Turing Instability ◽  
Model System ◽  
Ode Model ◽  
Estuarine Ecosystem ◽  
Dynamical Study ◽  
Oscillatory Dynamics ◽  
The Stability ◽  
Microzooplankton Grazing

AbstractWe propose a model for tropic interaction among the infochemical-producing phytoplankton and non-info chemical-producing phytoplankton and microzooplankton. Volatile information-conveying chemicals (infochemicals) released by phytoplankton play an important role in the food webs of marine ecosystems. Microzooplankton is an ecologically important grazer of phytoplankton for coexistence of a large number of phytoplankton species. Here, we discuss how information transferred by dimethyl sulfide shapes the interaction of phytoplankton. Phytoplankton deterrents may lead to propagation of IPP bloom. The interaction between IPP and microzooplankton follows the Beddington–DeAngelis-type functional response. Analytically, we discuss boundedness, stability and Turing instability of the model system. We perform numerical simulation for temporal (ODE model) as well as a spatial model system. Our numerical investigation shows that microzooplankton grazing refuse of IPP leads to oscillatory dynamics. Increasing diffusion coefficient of microzooplankton shows Turing instability. Time evolution also plays an important role in the stability of system dynamics. The results obtained in this paper are useful to understand the dominance of algal bloom in coastal and estuarine ecosystem.

scholarly journals Copper Phyllosilicates-Derived Catalysts in the Production of Alcohols from Hydrogenation of Carboxylates, Carboxylic Acids, Carbonates, Formyls, and CO2: A Review

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 255
Author(s):  
Dien-Thien To ◽  
Yu-Chuan Lin
Keyword(s):  
Carboxylic Acids ◽  
Catalytic Performance ◽  
Spatial Effect ◽  
Synthesis Methods ◽  
The Past ◽  
Surface Areas ◽  
Preparation Conditions ◽  
Remedial Actions ◽  
The Stability ◽  
Size Interaction

Copper phyllosilicates-derived catalysts (CuPS-cats) have been intensively explored in the past two decades due to their promising activity in carbonyls hydrogenation. However, CuPS-cats have not been completely reviewed. This paper focuses on the aspects concerning CuPS-cats from synthesis methods, effects of preparation conditions, and dopant to catalytic applications of CuPS-cats. The applications of CuPS-cats include the hydrogenation of carboxylates, carboxylic acids, carbonates, formyls, and CO2 to their respective alcohols. Besides, important factors such as the Cu dispersion, Cu+ and Cu0 surface areas, particles size, interaction between Cu and supports and dopants, morphologies, and spatial effect on catalytic performance of CuPS-cats are discussed. The deactivation and remedial actions to improve the stability of CuPS-cats are summarized. It ends up with the challenges and prospective by using this type of catalyst.

scholarly journals Advances in Molecularly Imprinted Polymers as Drug Delivery Systems

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3589
Author(s):  
Rui Liu ◽  
Alessandro Poma
Keyword(s):  
Drug Delivery ◽  
Molecularly Imprinted Polymers ◽  
Drug Loading ◽  
Stimuli Responsive ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Drug Delivery Vehicles ◽  
The Past ◽  
Drug Molecules ◽  
Delivery Vehicles

Despite the tremendous efforts made in the past decades, severe side/toxic effects and poor bioavailability still represent the main challenges that hinder the clinical translation of drug molecules. This has turned the attention of investigators towards drug delivery vehicles that provide a localized and controlled drug delivery. Molecularly imprinted polymers (MIPs) as novel and versatile drug delivery vehicles have been widely studied in recent years due to the advantages of selective recognition, enhanced drug loading, sustained release, and robustness in harsh conditions. This review highlights the design and development of strategies undertaken for MIPs used as drug delivery vehicles involving different drug delivery mechanisms, such as rate-programmed, stimuli-responsive and active targeting, published during the course of the past five years.

scholarly journals Thermodynamic and Energy Efficiency Analysis of a Domestic Refrigerator Using Al2O3 Nano-Refrigerant

2021 ◽  
Vol 13 (10) ◽  
pp. 5659
Author(s):  
Farhood Sarrafzadeh Javadi ◽  
Rahman Saidur
Keyword(s):  
Temperature Gradient ◽  
Technological Changes ◽  
Nanoparticle Concentration ◽  
Evaporator Temperature ◽  
Domestic Refrigerator ◽  
The Past ◽  
Nano Lubricant ◽  
The Stability ◽  
Energy Efficiency Analysis ◽  
Al2o3 Nanofluid

Refrigeration systems have experienced massive technological changes in the past 50 years. Nanotechnology can lead to a promising technological leap in the refrigeration industry. Nano-refrigerant still remains unknown because of the complexity of the phase change process of the mixture including refrigerant, lubricant, and nanoparticle. In this study, the stability of Al2O3 nanofluid and the performance of a nano-refrigerant-based domestic refrigerator have been experimentally investigated, with the focus on the thermodynamic and energy approaches. It was found that by increasing the nanoparticle concentration, the stability of nano-lubricant was decreased and evaporator temperature gradient was increased. The average of the temperature gradient increment in the evaporator was 20.2% in case of using 0.1%-Al2O3. The results showed that the energy consumption of the refrigerator reduced around 2.69% when 0.1%-Al2O3 nanoparticle was added to the system.

scholarly journals Guidelines for Genetic Nomenclature and Community Governance for the Model Legume Medicago truncatula

2001 ◽  
Vol 14 (12) ◽  
pp. 1364-1367 ◽  
Author(s):  
Kathryn A. VandenBosch ◽  
Julia Frugoli
Keyword(s):  
Medicago Truncatula ◽  
Rapid Growth ◽  
Model System ◽  
Gene Nomenclature ◽  
Community Governance ◽  
Model Legume ◽  
The Past ◽  
Genetic Nomenclature ◽  
International Collaborations

At the 2nd Medicago meeting (a satellite of the 1999 IS-MPMI meeting in Amsterdam), investigators perceived a need for standardization of genetic nomenclature in Medicago truncatula, due to the rapid growth of research on this species in the past few years. Establishment of such standards grew out of discussions begun at this meeting and continued electronically throughout the M. truncatula community. The proposed standards presented here are the consensus results of those discussions. In addition to standards for gene nomenclature, a method for community governance and a website for cataloging gene names and submitting new ones are presented. The purpose of implementing these guidelines is to help maintain consistency in the literature, to avoid redundancy, to contribute to the accuracy of databases, and, in general, to aid the international collaborations that have made M. truncatula a model system for legume biology.

scholarly journals Water confined in solutions of biological relevance

2020 ◽  
Vol 92 (10) ◽  
pp. 1563-1574
Author(s):  
Marie-Claire Bellissent-Funel
Keyword(s):  
Aqueous Solutions ◽  
Bulk Water ◽  
Biological Macromolecules ◽  
Organic Solutes ◽  
Confined Water ◽  
The Past ◽  
Structure And Dynamics ◽  
Biological Relevance ◽  
The Stability

AbstractIn many relevant situations, water is not in its bulk form but instead attached to some substrates or filling some cavities. We shall call water in the latter environment confined water as opposed to bulk water. It is known that the confined water is essential for the stability and the function of biological macromolecules. In this paper, we provide a review of the experimental and computational advances over the past decades concerning the understanding of the structure and dynamics of water confined in aqueous solutions of biological relevance. Examples involving water in solution of organic solutes (cryoprotectants such as dimethylsulfoxide (DMSO), sugars such as trehalose) are provided.

Magnetic nanoparticles (Fe3O4 NPs) fabricated composite microgels and their applications in different fields

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Khalida Naseem
Keyword(s):  
Research Progress ◽  
Composite Particles ◽  
External Magnet ◽  
Drug Delivery Vehicles ◽  
Microgel Particles ◽  
Delivery Vehicles ◽  
The Stability ◽  
Nano Formulation ◽  
Magnetic Nanoparticles Fe3o4 ◽  
Micro Reactor

Abstract This article encircles the research progress of Fe3O4 NPs loaded composite microgel particles. Preparation methodologies, properties and applications of Fe3O4 NPs loaded composite microgel particles are elaborated here. The effect of different factors on the stability and tunable properties of Fe3O4 NPs loaded composite microgel particles was also investigated in detail. These composite particles have exceptional magnetic properties that make them demanding composite nano-formulation in different fields. Applications of these composite microgel particles in different fields as micro-reactor, drug delivery vehicles, and in adsorption and catalysis have also been elaborated in detail. These composite microgel particles can easily be recovered from the reaction mixture by applying an external magnet due to the presence of fabricated Fe3O4 NPs.

Future Directions in Surface Electromyography

Biofeedback ◽  
2010 ◽  
Vol 38 (2) ◽  
pp. 78-82 ◽  
Author(s):  
John G. Arena
Keyword(s):  
Surface Electromyography ◽  
Ambulatory Monitoring ◽  
Future Directions ◽  
The Past ◽  
Psychophysiological Assessment ◽  
The Future ◽  
The Stability

Abstract The use of surface electromyography (SEMG) has increased exponentially in the past four decades. SEMG is one of the most widespread measures employed today in psychophysiological assessment and one of three primary biofeedback modalities. This article briefly outlines three areas that the author believes are important for SEMG to address if it is to continue to flourish in the future: applications in telehealth, the use of telemetry and ambulatory monitoring, and studies on the stability or reliability of surface electromyography.

scholarly journals Spatial aspect of modern warfare: from traditional warfare to cyberwar

2021 ◽  
pp. 136-149
Author(s):  
Natalia Aleksandrovna Balakleets
Keyword(s):  
Military Leaders ◽  
The Past ◽  
The Earth ◽  
Total Destruction ◽  
Spatial Aspect ◽  
Pessimistic Scenario ◽  
The Stability ◽  
Military Activity ◽  
Modern Warfare ◽  
The Military

This author substantiates the thesis on the importance of spatial factors for conducting warfare. The article traces the evolution of warfare associated with the involvement of new territories and new types of spaces in the orbit of military activity. If the warfare of the past demonstrated a direct dependence on the geographical territory and the related “tensions” (C. von Clausewitz), the modern warfare are emancipated from the geographical shell of the Earth. The article explicates the factors that justify the need for arranging the new warfare spaces. Special attention is given to cyberspace, its structure, and conflicts unfolding therein. The scientific novelty of consists in the interpretation of cyberspace as an expected result of the spatial evolution of warfare. The conclusion is drawn that the emergence of cyberspace contributes to solution of the problem of information vagueness and creation of the stability zones for the military leaders, but at the same is a source of problems not less dangerous for the humanity. The cyberwar winner faces a tempting challenge of establishing global control over the territory of the plane using cyberweapon, or in most pessimistic scenario, its total destruction.

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