Maximum Activity Research Articles

Genome Analysis of Multiple Polysaccharide-Degrading Bacterium Microbulbifer thermotolerans HB226069: Determination of Alginate Lyase Activity.

Polysaccharide-degrading bacteria are key participants in the global carbon cycle and algal biomass recycling. Herein, a polysaccharide lyase-producing strain HB226069 was isolated from Sargassum sp. from Qingge Port, Hainan, China. Results of the phylogenetic of the 16S rRNA gene and genotypic analysis indicated that the isolate should be classified as Microbulbifer thermotolerans. The whole genome is a 4,021,337bp circular chromosome with a G+C content of 56.5%. Analysis of the predicted genes indicated that strain HB226069 encoded 161 carbohydrate-active enzymes (CAZymes), and abundant putative enzymes involved in polysaccharide degradation were predicted, including alginate lyase, fucosidase, agarase, xylanase, cellulase, pectate lyase, amylase, and chitinase. Three of the putative polysaccharide lyases from PL7 and PL17 families were involved in alginate degradation. The alginate lyases of strain HB226069 showed the maximum activity of 117.4 U/mL at 50°C, pH 7.0, and 0.05M FeCl3, while exhibiting the best stability at 30°C and pH 7.0. The Thin Layer Chromatography (TLC) and Electrospray Ionization Mass Spectrometry (ESI-MS) analyses indicated that the alginate oligosaccharides (AOSs) degraded by the partially purified alginate lyases contained oligosaccharides of DP2-DP5 and monosaccharide while reacting for 36h. The complete genome of M. thermotolerans HB226069 enriches our understanding of the mechanism of polysaccharide lyase production and supports its potential application in polysaccharide degradation.

Unraveling Hydrogen Adsorption on Transition Metal-Doped [Mo3S13]2- Clusters: Insights from Density Functional Theory Calculations.

Molecular and dissociative hydrogen adsorption of transition metal (TM)-doped [Mo3S13]2- atomic clusters were investigated using density functional theory calculations. The introduced TM dopants form stable bonds with S atoms, preserving the geometric structure. The S-TM-S bridging bond emerges as the most stable configuration. The preferred adsorption sites were found to be influenced by various factors, such as the relative electronegativity, coordination number, and charge of the TM atom. Notably, the presence of these TM atoms remarkably improved the hydrogen adsorption activity. The dissociation of a single hydrogen molecule on TM[Mo3S13]2- clusters (TM = Sc, Cr, Mn, Fe, Co, and Ni) is thermodynamically and kinetically favorable compared to their bare counterparts. The extent of favorability monotonically depends on the TM impurity, with a maximum activation barrier energy ranging from 0.62 to 1.58 eV, lower than that of the bare cluster (1.69 eV). Findings provide insights for experimental research on hydrogen adsorption using TM-doped molybdenum sulfide nanoclusters, with potential applications in the field of hydrogen energy.

Intensification of α-amylase activity using ultrasound and its application for food waste hydrolysis

The current research aims to study the ultrasound assisted intensification of activity of commonly applied amylase enzyme, under varying parameters like power, frequency, duty cycle, temperature and enzyme concentration. Two ultrasonic reactor configurations as bath and horn are used for comparing the efficacy of reactor configuration. The initial activity of native amylase was found as 5.77 U/g at optimum temperature of 35° C and pH 7. Under US bath treatment, α amylase attained maximum activity of 7.498 U/g at best treatment conditions of 120 W power, 30% duty cycle and 15 minutes of exposure time. In the case of US horn, application of 60 W power, 30% duty cycle, and 5 minutes of exposure increased the enzyme activity to 6.907 U/ g. Set of treatment approaches explored for obtaining highest yield of reducing sugars revealed the best approach of ultrasonic treatment of food waste followed by ultrasonic bath intensified amylase hydrolysis, yielding maximum amount of reducing sugars as 8.14 g/L in only 15 min. Overall the work elucidated the role of ultrasound in intensifying the enzyme activity as well as food waste hydrolysis maximizing the utilization of sustainable resource.

Inshights on antifungal potential of Bryum Argenteum in association with therapeutical clay smectite and silver nanoparticles

This work presents the development of a novel antifungal ternary approach that is eco-friendly, biocompatible, and cost-effective. It consists of Bryum argenteum extract, silver nanoparticles, and healing clay smectite. The research focuses on the green production of silver nanoparticles using an aqueous extract of Bryum argenteum as a stabilizing and reducing agent, as well as the synthesis of clay dispersion and plant extract. The silver nanoparticles were characterized by FTIR, SEM, UV–Vis spectroscopy, and XRD. Using a standard phytochemical screening procedure, the aqueous, ethanolic, and acetonic extracts of Bryum argenteum were subjected to phytochemical screening. Silver nanoparticles and plant extract were evaluated for their antioxidant properties using DPPH scavenging activity at 517 nm. Using the agar well diffusion method, a number of investigations have been conducted on the antifungal potential of the proposed innovative ternary approach against Rhizopus oryzae (R. oryzae) and Aspergillus Niger (A. Niger). The color shift validated the silver nanoparticle generation, and the maximum absorbance at 432.11 nm was observed employing UV–Vis spectroscopy. Several functional groups responsible for the synthesis of AgNPs were identified by Fourier transform infrared spectroscopy. The particles are spherical in shape, with the range of 10 nm to 50 nm in size. Both ethanolic and aqueous extracts of Bryum argenteum contain sterols, flavonoids, cardiac glycosides, and terpenoids. AgNPs have stronger antioxidant activity in comparison to the aqueous extract of Bryum argenteum. Out of all the individual components, AgNPs demonstrated the strongest antifungal activity, with clay and plant extract coming in second and third, respectively. Additionally, their binary composition exhibits a synergistic effect with each combination. However, the ternary combination consisting of smectite clay, Bryum argenteum mediated silver nanoparticles, and Bryum argenteum extract showed exceptional antifungal efficiency against the mentioned fungus species. In respect to the zone of inhibition, the maximal antifungal activity was correlated with concentration and pH. ConclusionIt is concluded here that the proposed ternary system has significant antifungal potential. Future technological and medicinal studies will find this new ternary system to be an invaluable tool.

Removal of cadmium through biomineralization using halophilic and ureolytic bacteria under saline conditions

Heavy metal pollution poses an immense challenge to humanity owing to its severe toxic effects on living beings. This study investigates the bioremediation potential of the urease-hydrolyzing and halophilic bacterium Bacillus paramycoides- MSR1 to reduce the toxicity of cadmium (Cd) in the environment under salt stress through microbially induced calcium carbonate precipitation (MICCP). The enzymatic activity of urease and calcium carbonate (CaCO3) precipitation was studied under different concentrations of salt stress (0%, 3.5%, 5%, 7.5%, 10%, 15%) and maximum urease activity of 735.7 U/ml was recorded at 5% salt stress. The urease activity and CaCO3 precipitation decreased with increasing Cd toxicity (0, 10, 20, 30, 40, 50, and 60 μM). The maximum concentration of Cd endured by bacteria was determined by IC50 value and the minimum inhibitory concentration of Cd was recorded as 9.86 μM under 5% stress. Atomic absorption spectroscopy results revealed that Cd removal was as high as 90.3% under 5% salt stress. Microstructural analysis through FE-SEM revealed the surface topography of carbonate crystals as rhombohedral, whereas EDS confirmed the presence of CaCO3 and Cd in the bio-precipitates. These results suggest that MICCP is a potential, environmentally safe, low-cost technique and an excellent alternative to conventional heavy metal removal strategies from the environment.

Imine-functionalized organotin(IV) carboxylates: Syntheses, structures and antibacterial activities

Six new imine-functionalized organotin(IV) carboxylates viz. {[(n-Bu)2Sn(L1)]2O]}2 (1), [(t-Bu)2Sn(L1)2] (2), [Ph3Sn(L1)] (3), [(t-Bu)4Sn2(OH)2(L2)2] (4), [Ph3Sn(L2)] (5) and [(t-Bu)2Sn(L3)2] (6) have been synthesized and characterized by FT-IR spectroscopy, elemental analysis, 1H, 13C{1H} and 119Sn{1H} NMR spectroscopy. The solid-state molecular structures of all compounds have been elucidated by single-crystal X-ray diffraction analyses. Compound 1 shows a ladder-type structure consisting of four tin atoms. Compounds 2–3 and 5–6 are mononuclear and contain only one tin atom in each compound. Interestingly, compound 4 exhibits a hydroxide-bridged dinuclear structure. All compounds were evaluated for their antibacterial activities against E. coli XL-1 Blue cells, and compound 1 showed maximum activity amongst all compounds.

Low-Volume Speed Endurance Training with Reduced Volume Improves Short-Term Exercise Performance in Highly Trained Cyclists.

We investigated the effects of low and high volume speed endurance training (SET), with a reduced training volume, on sprint ability, short- and long-term exercise capacity, muscle mitochondrial properties, ion transport proteins and maximal enzyme activity in highly trained athletes. Highly-trained male cyclists (V̇O2max: 68.3 ± 5.0 mL × min-1 × kg-1, n = 24) completed six weeks of either low (SET-L; 6x30-s intervals, n = 8) or high (SET-H; 12 × 30-s intervals, n = 8) volume SET twice per week with a 30%-reduction in training volume. A control group (CON, n = 8) maintained their training. Exercise performance was evaluated by i) 6-s sprinting, ii) a 4-min time trial, iii) a 60-min preload at 60% V̇O2max followed by a 20-min time trial. A biopsy of m. vastus lateralis was collected before and after the training intervention. In SET-L, 4-min time trial performance was improved (P < 0.05) by 3.8%, with no change in SET-H and CON. Sprint ability, prolonged endurance exercise capacity, V̇O2max, muscle mitochondrial respiratory capacity, maximal citrate synthase activity, fiber-type specific mitochondrial proteins (complex I - V) and PFK content did not change in any of the groups. In SET-H, maximal activity of muscle PFK and abundance of Na+-K+ pump-subunit α1, α2, β1, and phospholemman (FXYD1) were 20%, 50%, 19%, 24%, and 42 % higher (P < 0.05), respectively after compared to before the intervention, with no changes in SET-L or CON. Low SET volume combined with a reduced aerobic low and moderate intensity training volume does improve short duration intense exercise performance and maintain sprinting ability, V̇O2max, endurance exercise performance and muscle oxidative capacity, whereas, high volume of SET appears necessary to upregulate muscle ion transporter content and maximal PFK activity in highly trained cyclists.

Green biocatalyst for decolorization of azo dyes from industrial wastewater: Coriolopsis trogii 2SMKN laccase immobilized on recycled brewer's spent grain.

This study presents an innovative approach for the reuse and recycling of waste material, brewer's spent grain (BSG) for creating a novel green biocatalyst. The same BSG was utilized in several consecutive steps: initially, it served as a substrate for the cultivation and production of laccase by a novel isolated fungal strain, Coriolopsis trogii 2SMKN, then, it was reused as a carrier for laccase immobilization, aiding in the process of azo dye decolorization and finally, reused as recycled BSG for the second successful laccase immobilization for six guaiacol oxidation, contributing to a zero-waste strategy. The novel fungal strain produced laccase with a maximum activity of 171.4 U/g after 6 days of solid-state fermentation using BSG as a substrate. The obtained laccase exhibited excellent performance in the decolorization of azo dyes, both as a free and immobilized, at high temperatures, without addition of harmful mediators, achieving maximum decolorization efficiencies of 99.0%, 71.2%, and 61.0% for Orange G (OG), Congo Red, and Eriochrome Black T (EBT), respectively. The immobilized laccase on BSG was successfully reused across five cycles of azo dye decolorization process. Notably, new green biocatalyst outperformed commercial laccase from Aspergillus spp. in the decolorization of OG and EBT. GC-MS and LC-MS revealed azo-dye degradation products and decomposition pathway. This analysis was complemented by antimicrobial and phytotoxicity tests, which confirmed the non-toxic nature of the degradation products, indicating the potential for safe environmental disposal.

Cloning and catalytic profile of Hyalomma dromedarii leucine aminopeptidase

Ticks have harmful impacts on both human and animal health and cause considerable economic losses. Leucine aminopeptidase enzymes (LAP) play important roles during tick infestation to liberate vital amino acids necessary for growth. The aim of the current study is to identify, express and characterize the LAP from the hard tick Hyalomma dromedarii and elucidate its biochemical characteristics. We cloned an open reading frame of 1560 bp encoding a protein of 519 amino acids. The LAP full-length was expressed in Escherichia coli BL21 (DE3) and purified. The recombinant enzyme (H.d rLAP- 6×His) had a predicted molecular mass of approximately 55 kDa. Purification and the enzymatic characteristics of H.d rLAP- 6×His were studied. The purified enzyme showed maximum activity at 37 °C and pH 8.0–8.5 using Leu-p-nitroanilide as a substrate. The activity of H.d rLAP- 6×His was sensitive to β-mercaptoethanol, dl-dithiothreitol, 1,10- phenanthroline, bestatin HCl, and EDTA and completely abolished by 0.05 % SDS. In parallel, the enzymatic activity was enhanced by Ni2+, Mn2+ and Mg2+, partially inhibited by Na+, Cu2+, Ca2+ and completely inhibited by Zn2+.

Synthesis and biological properties of novel glucose-based fluoro segmented macromolecular architectures

The emergence of novel well-defined biological macromolecular architectures containing fluorine moieties displaying superior functionalities can satisfactorily address many biomedical challenges. In this research, ABA- and AB-type glucose-based biological macromolecules were synthesized using acryl-2,3,4,6-tetra-O-acetyl-D-glucopyranoside with pentafluorophenyl (FPM), pentafluorobenzyl (FBM), phenyl (PM) and benzyl (BM) methacrylate-based macro-RAFT agents following RAFT polymerization. The macro-RAFT agents and the corresponding copolymers were characterized by 19F, 1H, and 13C NMR and FTIR spectroscopic techniques to understand the chemical structure, molecular weight by size-exclusion chromatography, thermal analysis by TGA and DSC. Thermal stability (Td5%) of the FPM and FBM fluoro-based polymers was observed in the range of 219–267 °C, while the non-fluoro PM and BM polymers exhibited in the range of 216–264 °C. Among the macro-RAFT agents, PFPM (107 °C, ΔH: 0.613 J/g) and PPM (103 °C, ΔH: 0.455 J/g) showed higher Tm values, while among the block copolymers, PFBM-b-PG (123 °C, ΔH: 0.412 J/g) and PG-b-PFPM-b-PG (126 °C, ΔH: 0.525 J/g) exhibited higher Tm values. PFBMT and PPM macro-RAFT agents, PPM-b-PG and PG-b-PPM-b-PG copolymer spin-coated films showed the highest hydrophobicity (120°) among the synthesized polymers. The block copolymers exhibited self-assembled segregation by using relatively hydrophobic segments as the core and hydrophilic moieties as the corona. Synthesized biological macromolecules exhibit maximum antibacterial activity towards S. aureus than E. coli bacteria. Fluorophenyl (PFPM) and non-fluorobenzyl-based (PBMT) macro-RAFT agents exhibit low IC50 values, suggesting high cytotoxicity. All the triblock copolymers exhibit lesser cytotoxicity than the di-block polymers.

Cosmic-ray exposure assessment using particle and heavy ion transport code system: case study Douala-Cameroon.

According to UNSCEAR, cosmic radiation contributes to ~16% (0.39mSv/y) of the total dose received by the public at sea level. The exposure to cosmic rays at a specific location is therefore a non-negligible parameter that contributes to the assessment of the overall public exposure to radiation. In this study, simulations were conducted with the Particle and Heavy Ion Transport code System, a Monte Carlo code, to determine the fluxes and effective dose due to cosmic rays received by the population of Douala. In minimum solar activity, the total effective dose considering the contribution of neutron, muon+, muon-, electron, positron and photon, was found to be 0.31±0.02mSv/y at the ground level. For maximum solar activity, it was found to be 0.27±0.02mSv/y at ground level. During maximum solar activity, galactic cosmic rays are reduced by solar flares and winds, resulting in an increase in the solar cosmic-ray component and a decrease in the galactic cosmic-ray component on Earth. This ultimately leads to a decrease in the total cosmic radiation on Earth. These results were found to be smaller than the UNSCEAR values, thus suggesting a good estimation for the population of Douala city located near the equatorial line. In fact, the cosmic radiation is more deflected at the equator than near the pole. Muons+ were found to be the main contributors to human exposure to cosmic radiation at ground level, with ~38% of the total effective dose due to cosmic exposure. However, electrons and positrons were found to be the less contributors to cosmic radiation exposure. As regards the obtained results, the population of Douala is not significantly exposed to cosmic radiation.

Exploring Human-Exoskeleton Interaction Dynamics: An In-Depth Analysis of Knee Flexion-Extension Performance across Varied Robot Assistance-Resistance Configurations.

Knee rehabilitation therapy after trauma or neuromotor diseases is fundamental to restore the joint functions as best as possible, exoskeleton robots being an important resource in this context, since they optimize therapy by applying tailored forces to assist or resist movements, contributing to improved patient outcomes and treatment efficiency. One of the points that must be taken into account when using robots in rehabilitation is their interaction with the patient, which must be safe for both and guarantee the effectiveness of the treatment. Therefore, the objective of this study was to assess the interaction between humans and an exoskeleton during the execution of knee flexion-extension movements under various configurations of robot assistance and resistance. The evaluation encompassed considerations of myoelectric activity, muscle recruitment, robot torque, and performed movement. To achieve this, an experimental protocol was implemented, involving an individual wearing the exoskeleton and executing knee flexion-extension motions while seated, with the robot configured in five distinct modes: passive (P), assistance on flexion (FA), assistance on extension (EA), assistance on flexion and extension (CA), and resistance on flexion and extension (CR). Results revealed distinctive patterns of movement and muscle recruitment for each mode, highlighting the complex interplay between human and robot; for example, the largest RMS tracking errors were for the EA mode (13.72 degrees) while the smallest for the CR mode (4.47 degrees), a non-obvious result; in addition, myoelectric activity was demonstrated to be greater for the completely assisted mode than without the robot (the maximum activation levels for the vastus medialis and vastus lateralis muscles were more than double those when the user had assistance from the robot). Tracking errors, muscle activations, and torque values varied across modes, emphasizing the need for careful consideration in configuring exoskeleton assistance and resistance to ensure effective and safe rehabilitation. Understanding these human-robot interactions is essential for developing precise rehabilitation programs, optimizing treatment effectiveness, and enhancing patient safety.

Automated radiolabelling of [68Ga]Ga-PSMA-11 (gallium (68Ga)-gozetotide) using the Locametz® kit and two generators

BackgroundSteps have been taken by pharmaceutical companies to obtain marketing authorisation of PSMA ligands in the European Union. Since December 2022, Locametz® (PSMA-11, gozetotide) is licensed as kit for manual radiolabelling with gallium-68 and commercially available since mid-2023. The Summary of Product Characteristic (SmPC) describes manual radiolabelling with a maximum activity after radiolabelling of 1369 MBq. We aimed for radiolabelling with a higher activity to increase production efficiency, and thus, automated radiolabelling is strongly preferred over manual radiolabelling to reduce radiation exposure to personnel. The aim of this study was to develop and validate a method for automated radiolabelling of the Locametz® kit using ~ 2000 MBq of gallium-68 eluate for radiolabelling.ResultsAutomated radiolabelling of [68Ga]Ga-PSMA-11 using the Locametz® kit provided a product which complies to the Ph. Eur., had a shelf-life of 6 h at room temperature, and theoretically reduced radiation exposure 5.7 times. Radiolabelling with one and two generator(s) resulted in a radiochemical yield of 91–102% and 96–101% after preparation, respectively. The radiochemical purity ranged from 98.0 to 99.6% for radiolabelling with one generator and ranged from 98.4 to 99.3% for radiolabelling with two generators with similar stability. The activity of the final product was much higher when using two generators, 1961–2035 MBq compared to 740–1260 MBq, which leads to ~ 1.5 times more patient syringes available per preparation.ConclusionAutomated radiolabelling of [68Ga]Ga-PSMA-11 using the Locametz® kit with higher gallium-68 activity than specified in the SmPC results in a product that is in compliance with the Ph. Eur. monograph and has a shelf-life of 6 h at room temperature. Radiolabelling with two generators proved possible and resulted in a product with similar quality but with much higher efficiency.

Research of Acoustic Cavitation: Results, Practical Implementation and Development Prospects

The most significant results of research performed in the Belarusian State University University of Informatics and Radioelectronics, aimed at creating methods and instruments for monitoring cavitation and controlling its activity, are presented. To achieve this goal, it was necessary to clarify the mechanisms and patterns of new and little-studied phenomena: ultrasonic capillary effect, sonoluminescence, cavitation noise and its spectral components and evaluate the possibilities of their use for hardware implementation as cavitation indicators. New cavitation phenomena have been discovered: reverse ultrasonic capillary effect, generation of constant EMF under the influence of alternating pressure of ultrasonic frequency; acoustic clearing of the cavitation area with pulsed modulation of the ultrasonic field, the effect of long-term memory of the cavitation properties of the liquid. Previously unknown patterns have been established: it is shown that the cavitation region goes through four stages of development with increasing ultrasound intensity; a theorem on the maximum cavitation activity was formulated; the spectral characteristics of cavitation noise were established, correlating with the intensity of sonoluminescence. It has been shown that pulsed modulation of the ultrasonic field makes it possible to control the dynamics of the development of the cavitation region and the activity of cavitation. Based on the data obtained, new methods and instruments have been developed to study cavitation and control its activity. In a number of parameters, the created equipment surpasses the best world samples, what is confirmed by deliveries to the Russia, EU countries, China, USA and South Korea.

Biochemical characterization of a novel acid-active endopolygalacturonase for pectin depolymerization, pectic-oligomer production, and fruit juice clarification

Endopolygalacturonases are crucial pectinases known for their efficient and sustainable pectin depolymerization activities. The present study identified a novel gene encoding endopolygalacturonase from an acidic mine tailing metagenome. The putative gene showed a maximum identity of 67.55 % with an uncharacterized peptide sequence from Flavobacterium fluvii. The gene was cloned and expressed in a heterologous host, E. coli. Biochemical characterization of the novel endopolygalacturonase enzyme variant (EPHM) showed maximum activity at 60 °C and at 5.0 pH, while retaining 50 % activity under the temperature and pH range of 20 °C to 70 °C for 6 h, and 3.0 to 10.0 for 3 h, respectively. The enzyme exhibited tolerance to different metal ions. EPHM was characterized for the depolymerization of methylated pectin into pectic oligosaccharides. Further, its utility was established for fruit juice clarification, as endorsed by high transmittance, significant viscosity reduction, and release of reducing sugars in the treated fruit juice samples.

Neem Leaves Extract (Azadirachta indica) and Its Bactericidal Activity against Biofilm-forming Pathogenic Bacteria

Antibiotics are used in healthcare as for prophylaxis and have therapeutic value against drug-resistant bacteria. The main aim of the study was to analyze the potential of neem leaf extract against pathogenic bacteria. The leaves were dried and phytochemicals were extracted with methanol, ethyl acetate, chloroform, and water. The methanol extract showed maximum yield. The total phenolic and flavonoid contents were found to be maximum in methanol extract. The methanol extract showed maximum activity followed by ethyl acetate, chloroform, and water. The methanol extract exhibited maximum activity against Enterobacter aerogenes (18±2 mm zone of inhibition), Salmonella typhimurium (16±1 mm zone of inhibition), Pseudomonas aeruginosa (20±2 mm zone of inhibition), Staphylococcus aureus (12±0 mm zone of inhibition), and Escherichia coli (20±0 mm) (p&lt;0.05). The minimum inhibitory concentration values ranged from 6.25±1.25 to 300±125 µg/ml and methanol extract showed least value against bacteria (p&lt;0.05).

Factors Associated with Fatigue in COVID-19 ICU Survivors.

Approximately 30% of people infected with COVID-19 require hospitalization and 20% of them are admitted to an intensive care unit (ICU). Most of these patients experience symptoms of fatigue weeks post-ICU, so understanding the factors associated with fatigue in this population is crucial. Fifty-nine patients [38-78 yr] hospitalized in ICU for COVID-19 infection for 32 [6-80] days including 23 [3-57] days of mechanical ventilation, visited the laboratory on two separate occasions. The first visit occurred 52 ± 15 days after discharge and was dedicated to questionnaires, blood sampling and cardiopulmonary exercise testing, while measurements of the knee extensors neuromuscular function and performance fatigability were performed in the second visit 7 ± 2 days later. Using the FACIT-F questionnaire, 56% of patients were classified as fatigued. Fatigued patients had worse lung function score than non- fatigued (i.e. 2.9 ± 0.8 L vs 3.6 ± 0.8 L; 2.4 ± 0.7 l vs 3.0 ± 0.7 L for forced vital capacity and forced expiratory volume in one second, respectively) and forced vital capacity was identified as a predictor of being fatigued. Maximal voluntary activation was lower in fatigued patients than non-fatigued patients (82 ± 14% vs 91 ± 3%) and was the only neuromuscular variable that discriminated between fatigued and non-fatigued patients. Patient-reported outcomes also showed differences between fatigued and non-fatigued patients for sleep, physical activity, depression and quality of life (p < 0.05). COVID-19 survivors showed altered respiratory function 4 to 8 weeks after discharge, that was further deteriorated in fatigued patients. Fatigue was also associated with lower voluntary activation and patient-reported impairments (i.e. sleep satisfaction, quality of life or depressive state). The present study reinforces the importance of exercise intervention and rehabilitation to counteract cardiorespiratory and neuromuscular impairments of COVID-19 patients admitted in ICU, especially individuals experiencing fatigue.

Degradation of textile polyazodyes by Polyporus ciliatus laccase produced in peanut shell solid medium: purification and characterization

This study describes decolorization of reactive sulfonated azoic dye Direct Blue 71, one of the recalcitrant and highly used industrial dyes, by Polyporus ciliatus derived laccase. Agro-industrial wastes are increasingly used as substrates for laccase production from white rot fungi through solid-state fermentation (SSF). Peanut shell (PS) is an attractive substrate for laccase production, and SSF is an adequate strategy for that purpose. It has been employed as a novel support-substrate for laccase production by Polyporus ciliatus under solid-state fermentation. The highest laccase yield of 1260 U/ml was attained using PS after 13 days of incubation at 30°C. The purified laccase (55 kDa) showed maximum activity at pH 3 and 60°C. The extracellular laccase enzyme was purified 67.6-fold to a specific activity of 1466 U/mg by a Mono-Q anion-exchange column. The purified enzyme Km value was found to be 24 µM, while the Vmax value was observed to be 0.96 µM s-1 with ABTS as a substrate. It had high thermotolerance and pH stability and was resistant to several metal ions including copper, cadmium, and iron. P. ciliatus pure laccase showed high potential for the decolorization and detoxification of the reactive sulfonated azoic dye Direct Blue 71, which suggested that this enzyme could be used for textile effluent treatment.

Evaluation of bacteriostatic and antioxidant activities of various extracts from aerial part of Piper nigrum grown in Gulf countries traditionally used for the treatment of various infectious diseases

AbstractPiper nigrum (P. nigrum) is a tropical medicinal plant widely available in Southeast Asian countries including Oman. In Asian It has a long history of usage in places such as Oman for treating of rheumatism, colds, and various infections. Based on the medicinal uses, the purpose of this research is to create diverse fractions using increasing solvent polarity from the aerial part of the collected plant species and evaluate their antibacterial and antioxidant activities by using established bioassays. The aerial part was collected from the Southern part of Oman and processed using the standard method. The processed materials were recovered using the maceration method using methanol, and the methanol raw extracts was further fractionated with water extraction, butanol, ethyl acetate (ETA), hexane, and dichloromethane are produced using different liquid polarities. Each of the six plant extracts was tested for antioxidant and antibacterial potential at different concentrations against DPPH (1, 1-diphenyl-2-picrylhydrazyl) and agar diffusion methods. All of the fractions at varied concentrations shown promising antioxidant activity with DPPH against the gallic acid. The maximum activity was observed in hexane extract, while the smallest potential was noticed in butanol extract, in the following order: hexane &gt; chloroform &gt; water &gt; methanol &gt; ethyl acetate &gt; butanol extract. The antibacterial efficacy of six different polarities extracts gives moderate activity against two Gram-positive bacteria strains namely S. saprophyticus and S. aureus and three Gram-negative namely P. vulgaris, K. senegalensis and E. coli. Among the six extracts, hexane extract had the most antibacterial activity, whereas butanol extract had the smallest activity. The remaining four extracts, chloroform, ethyl acetate, methanol, and water, all had comparable activity. In conclusion, the extracts with the greatest activity from the chosen plant types might be employed as natural antioxidants to treat infectious disorders.

The quantitative molecular weight-antimicrobial activity relationship for chitosan polymers, oligomers, and derivatives

Chitosan and chitosan derivatives can kill pathogenic microorganisms including bacteria and fungi. The antimicrobial activity is dependent on the degree of acetylation, substituent structure, and molecular weight. Over the past four decades, numerous studies have endeavored to elucidate the relationship between molecular weight and the activity against microorganisms. However, investigators have reported divergent and, at times, conflicting conclusions. Here a bilinear equation is proposed, delineating the relationship between antimicrobial activity, defined as log (1/MIC), and the molecular weight of chitosan and chitosan derivatives. Three constants AMin, AMax, and CMW govern the shape of the curve determined by the equation. The constant AMin denotes the minimal activity expected as the molecular weight tends towards zero while AMax represents the maximal activity observed for molecular weights exceeding CMW, the critical molecular weight required for max activity. This equation was applied to analyze data from seven studies conducted between 1984 and 2019, which reported MIC (Minimum Inhibitory Concentration) values against bacteria and fungi for various molecular weights of chitosan and its derivatives. All the 29 datasets exhibited a good fit (R2 ≥ 0.5) and half excellent (R2 ≥ 0.95) fit to the equation. The CMW generally ranged from 4 to 10 KD for datasets with an excellent fit to the equation.