High level of lactate dehydrogenase and ischaemia-reperfusion injury regulate the multiple organ dysfunction in patients with COVID-19.

BACKGROUND: Multiple organ damage has been observed in patients with COVID-19, but the exact pathway is not known. Vital organs of the human body may get affected after replication of SARS-CoV-2, including the lungs, heart, kidneys, liver and brain. It triggers severe inflammation and impairs the function of two or more organ systems. Ischaemia-reperfusion (IR) injury is a phenomenon that can have disastrous effects on the human body. METHODS: In this study, we analysed the laboratory data of 7052 hospitalised patients with COVID-19 including lactate dehydrogenase (LDH). A total of 66.4% patients were men and 33.6% were women, which indicated gender difference as a prominent factor to be considered. RESULTS: Our data showed high levels of inflammation and elevated markers of tissue injury from multiple organs C reactive protein, white blood cell count, alanine transaminase, aspartate aminotransferase and LDH. The number of red blood cells, haemoglobin concentration and haematocrit were lower than normal which indicated a reduction in oxygen supply and anaemia. CONCLUSION: On the basis of these results, we proposed a model linking IR injury to multiple organ damage by SARS-CoV-2. COVID-19 may cause a reduction in oxygen towards an organ, which leads to IR injury.

Cholesterol extraction from ghee using glass beads functionalized with beta cyclodextrin.

Beta-cyclodextrin (ß-CD) was covalently immobilized on glass surface. Functionalized glass surface was characterized by X-ray photoelectron spectroscopy (XPS) and elemental analysis. Glass surface functionalized with ß-CD was used to remove cholesterol from ghee (clarified butter fat). 78.8 % cholesterol was reduced in 2 h at 25 °C and 170 rpm. Same surface was used repeatedly for 10 cycles and no reduction in cholesterol removal efficiency was observed. Modified glass surface showed almost no degradation in repeated use in cholesterol reduction experiments.

Design, synthesis, characterization and computational docking studies of novel sulfonamide derivatives.

This study reports three novel sulfonamide derivatives 4-Chloro-N-[(4-methylphenyl) sulphonyl]-N-propyl benzamide (1A), N-(2-hydroxyphenyl)-4-methyl benzene sulfonamide (1B) and 4-methyl-N-(2-nitrophenyl) benzene sulfonamide (1C). The compounds were synthesised from starting material 4-methylbenzenesulfonyl chloride and their structure was studied through 1H-NMR and 13C-NMR spectra. Computational docking was performed to estimate their binding energy against bacterial p-amino benzoic acid (PABA) receptor, the dihydropteroate synthase (DHPS). The derivatives were tested in vitro for their antimicrobial activity against Gram+ and Gram- bacteria including E. coli, B. subtilis, B. licheniformis and B. linen. 1A was found active only against B. linen; 1B was effective against E. coli, B. subtilis and B. linen whereas 1C showed activity against E. coli, B. licheniformis and B. linen. 1C showed maximum activity with minimum inhibitory concentration (MIC) of 50, 100 and 150 µg/mL against E. coli, B. licheniformis and B. linen respectively. 1C exhibited maximum affinity to DHPS with binding free energy of -8.1 kcal/mol. It enriched in the top 0.5 % of a library of 7663 compounds, ranked in order of their binding affinity against DHPS. 1C was followed by 1B which showed a moderate to low level MIC of 100, 250 and 150 µg/mL against E. coli, B. subtilis and B. linen respectively, whereas 1A showed a moderate level MIC of 100 µg/mL but only against B. linen. These derivatives may thus serve as potential anti-bacterial alternatives against resistant pathogens.

Kinetic and thermodynamic study of a chemically modified highly active xylanase from Scopulariopsis sp: existence of an essential amino group.

The amino groups of purified least acidic xylanase (LAX) isomer and carboxyl groups of purified highly acidic xylanase (HAX) isomer from Scopulariopsis sp. were chemically modified, resulting in charge neutralization and reversal. Modification of the second amino group was accompanied by the complete loss of enzyme activity in both the absence and presence of xylose. Multiple alignments of family 10 and 11 xylanases revealed that there is a pair of fully conserved Lys residues only in family 10 members. Xylanase structures from family 10 members showed that one of the conserved Lys residues is found near the active-site cleft that makes an H-bond with the substrate. The LAX and HAX isoenzymes in which one amino and three to four carboxyl groups were modified were subjected to kinetic and thermodynamic characterization. There were no differences in pH optima between the native and modified HAX, but there was a broadening of pH optimum toward the alkaline range for charge-neutralized LAX and a double pH optimum for charge-reversed LAX. TheV max/K m of both modified LAX and HAX decreased relative to the native species. The thermodynamics of xylan hydrolysis showed that the decrease in the catalytic activity of modified LAX enzymes was entropically driven. When compared with native enzyme, the thermostabilities of modified LAX enzymes increased in the presence and decreased in the absence of substrate. The thermodynamics of kinetic stability for modified LAX enzymes revealed that this increase in thermolability was owing to the decrease in DeltaH# with a concomitant increase in DeltaS# compared with native LAX. The thermostabilities of all the modified HAX species decreased except that of charge-neutralized HAX, whose half-life significantly increased in 50% (v/v) aqueous dioxan. These results suggest that the altered properties of the modified enzymes were a result of the conformational changes brought about by chemical modification.

A novel thermodynamic relationship based on Kramers Theory for studying enzyme kinetics under high viscosity.

In most studies of enzyme kinetics it has been found sufficient to use the classical Transition State Theory (TST) of Eyring and others. This theory was based on the solvent being an ideal dilute substance treated as a heat bath. However, enzymes found in organisms adapted to very low (psychrophiles) and very high (thermophiles) temperatures are also subjected to variable solute concentrations and viscosities. Therefore, the TST may not always be applicable to enzyme reactions carried out in various solvents with viscosities ranging from moderate to very high. There have been numerous advances in the theory of chemical reactions in realistic non-ideal solvents such as Kramers Theory. In this paper we wish to propose a modified thermodynamic equation, which have contributions from kcat, Km and the viscosity of the medium in which the enzyme reaction is occurring. These could be very useful for determining the thermodynamics of enzymes catalyzing reactions at temperature extremes in the presence of substrate solutions of different compositions and viscosities.