Didymin protects against polystyrene nanoplastic-induced hepatic damage in male albino rats by modulation of Nrf-2/Keap-1 pathway

Polystyrene nanoplastics (PS-NPs) are ubiquitous environmental pollutants that can cause oxidative stress in various organs, including the liver. Didymin is a dietary flavanone that displays multiple pharmacological activities. Therefore, the present study evaluated the palliative role of didymin against PS-NPs-induced hepatic damage in rats. Albino rats (n=48) were randomly distributed into 4 groups: control, PS-NPs treated group, PS-NPs + didymin co-administered group, and didymin supplemented group. After 30 days, PS-NPs intoxication lowered the expression of Nrf-2 and anti-oxidant genes [catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR), glutathione-S-transferase (GST), and heme oxygenase-1 (HO-1)], whereas the expression of KEAP1 kelch like ECH associated protein 1 (Keap-1) was increased. PS-NPs exposure also reduced the activities of anti-oxidants enzymes (CAT, SOD, GPx, GSR, GST, GSH, and OH-1), while malondialdehyde (MDA) and reactive oxygen species (ROS) levels were increased. The levels of alanine transaminase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were increased in PS-NPs-exposed rats. Moreover, inflammatory indices [interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), nuclear factor-kappa B (NF-κB), and cyclooxygenase-2 (COX-2)] were increased in PS-NPs-exposed rats. Furthermore, PS-NPs intoxication increased the expressions of apoptotic markers including Bax and Caspase-3, as well as reducing Bcl-2 expression. The histopathological analysis showed significant damage in PS-NPs-treated rats. However, didymin supplementation ameliorated all the PS-NPs-induced damage in the liver of rats. Therefore, it was concluded that didymin can act as a remedy against PS-NPs-induced liver toxicity due to its anti-apoptotic, anti-oxidant, and anti-inflammatory activities.

Separation and partial characterization of two of the extracellular endoglucanases of cellulomonas flavigena

Two extracellular endoglucanases of Cellulomonas flavigena were purified by acetone precipitation, gel filtration, ion-exchange chromatography and preparative gradient PAGE and named as endoglucanases E1 and E2. Both of these were only active against carboxymethyl cellulose [CMC] and their Km values were determined to be 7.8 and 20 g/l, respectively. Each of the enzyme gave glucose along with cellobiose as end product. Both the endoglucanases were most active at pH 6.5 - 7.0 and at 45 - 50°C. Each of the enzyme was inhibited by 20 mM glucose and cellobiose. Heavy metal ion e.g. Ag+ and Fe++ and B-mercaptoethanol strongly inhibited both the enzymes whereas slight inhibition was observed with Ca++. The enzymes are stable in the pH range of 3 - 10 and below 30°C. Molecular weights as determined by SDS-PAGE are 75,000 for endoglucanase E1 and 60,000 for the endoglucanase E2

Purification and characterization of a crystalline cellulose hydrolyzing enzyme of tricholderma harzianum

An Avicel-hydrolyzing cellulase was isolated from a shake flask culture of Trichoderma harzianum and purified by Sephadex G-75 gel filtration and DEAE-Sephadex A-50 chromatography. This cellulose component, called cellulase F, showed a single protein band by SDS-PAGE. Its molecular weight was found to be 50, 100 by SDS-PAGE and 47, 800 by gel filtration. It was most active at pH 4.5 to 5.0 and a temperature of 50°C. The enzyme was stable at the pH range 4.0 to 5.5 and lost its activity rapidly beyond the temperature of 50°C. Cellulose F was rich in acidic amino acids but poor in basic and sulphur containing amino acids. The hydrolytic activity of cellulase F on Avicel, filter paper and cotton was higher as compared to those on the soluble substrates. The hydrolytic products of the insoluble substrates contained high levels of cellobiose and cellotriose but low levels of glucose. Cellulase F was an essential component of the cellulase complex since it showed strong synergism with other components of the complex

Cellulase production by locally isolated trichoderma species

Production of cellulases by four different locally isolated species belonging to the genus Trichoderma was studied. The organisms were grown in a mineral salt medium containing 1% glucose, CMC, filter paper or Avicel in shake flasks. The order of cellulase productivity of the four species was T. harzianum > T. longibrachiatum > T. hamatum > T. piluliferum. The induction effect of different carbon sources was Avicel > filter paper > CMC > glucose for all the species. In the medium containing 1% Avicel T. harzianum produced 74.6, 11.5, 3.2 and 11.3 U of CMCase, avicelase, FPase and salicinase, respectively per 100 ml of the culture medium