Biophysical and Biochemical Characterization of the Receptor Binding Domain of SARS-CoV-2 Variants

The Protein Journal - The newly emerging SARS-CoV-2 variants are potential threat and posing new challenges for medical intervention due to high transmissibility and escaping neutralizing antibody...     

Tuftsin augments antitumor efficacy of liposomized etoposide against fibrosarcoma in Swiss albino mice

Anticancer drugs are generally plagued by toxic manifestations at doses necessary for control of various forms of cancer. Incorporating such drugs into liposomes not only reduces toxicity but also enhances the therapeutic index. Some antioxidants and potent immunomodulators have also been shown to impart significant antitumor activity presumably by nonspecific activation of the host immune system. In the present study, we evaluated augmentation of the antitumor activity of etoposide (ETP) by the immunomodulator tuftsin in Swiss albino mice with fibrosarcoma. The efficacies of the free form of ETP, liposomized ETP (Lip-ETP), and tuftsin-bearing liposomized ETP (Tuft-Lip-ETP) formulations were evaluated on the basis of tumor regression, effect on expression level of p53wt and p53mut, and survival of the treated animals. Tuft-Lip-ETP, when administered at a dosage of 10 mg/kg body weight/day for five days, significantly reduced tumor volume, delayed tumor growth, and also up-regulated the expression of p53wt. In contrast, although Lip-ETP delayed tumor growth, it did not decrease tumor size. The results of the present study suggest that tuftsin incorporation in drug-loaded liposomes is a promising treatment strategy for various forms of cancers, including fibrosarcoma.     

Evaluation of seedling age and nutrient sources on phenology,yield and agrometeorological indices for sweet corn (Zea mays saccharata L.)

The field experiment was conducted during Kharif season of 2020 at Agronomy farm of Faculty of Agriculture, Wadura, SKUAST-K to study the influence of age of seedling and sources of nutrients on phenology, yield and agrometeorological indices for sweet corn. The experiment included two factors viz. age of seedlings (12, 22 and 32 days old seedling) and sources of nutrients (control, RDF, 50 percent RDF + FYM @ 12 t ha⁻¹, 50 percent RDF + vermi-compost @ 4 t ha⁻¹ and 50 percent RDF + poultry manure @ 2 t ha⁻¹) tested in RCBD with three replications. Transplanting 12 days old seedlings required maximum number of days to attain different phenological stages, thereby accumulated maximum heat units followed by 22 days old seedlings. While as transplanting 22 days old seedling recorded significantly highest HUE, HTUE, PTUE and HyTUE and consequently resulted in the highest green cob and biological yield compared to other ages of seedlings. Among various sources of nutrients, application of 50 per cent RDF + poultry manure @ 2 t ha⁻¹ took maximum number of days to attain various phenophases thereby accumulated maximum heat units and registered highest HUE, HTUE, PTUE and HyTUE followed by application of 100 per cent RDF.     

Expression of recombinant Chrysanthemum virus B coat protein for raising polyclonal antisera

Chrysanthemum virus B (CVB genus Carlavirus, family Flexiviridae) is one of the major viral pathogens of chrysanthemum. This virus occurs worldwide, is a potential threat to the floriculture industry and hence is a quarantine pathogen. CVB has a positive sense single-stranded RNA (ssRNA) genome ~8.8 kb. The coat protein gene of CVB was amplified by RT-PCR, cloned and over expressed in E. coli BL21. The protein (CP) was expressed as a fusion protein with Glutathione S-Transferase (GST). Fused protein with GST was purified by GST tagged affinity chromatography and polyclonal (but monospecific) antibodies from rabbits immunized with the fusion protein was used for formulation of ELISA based diagnostic kit for CVB detection. The antisera produced showed specific reaction to CVB from infected chrysanthemums, Nicotiana glutinosa, Nicotiana clevelandii and Chenopodium quinoa at dilution of 1:1000 in ELISA. Results obtained were comparable (some times better) than commercial kit. The IgG against CVB performed favorably in specificity and sensitivity to the virus. Findings present a procedure for production of antibodies for CVB indexing of chrysanthemums propagative and mother stock materials to provide the disease free planting material.     

Ameliorative effect of carnosine and N-acetylcysteine against sodium nitrite induced nephrotoxicity in rats

The widespread use of sodium nitrite (NaNO₂) for various industrial purposes has increased human exposure to alarmingly high levels of nitrate/nitrite. Because NaNO ₂ is a strong oxidizing agent, induction of oxidative stress is one of the mechanisms by which it can exert toxicity in humans and animals. We have investigated the possible protection offered by carnosine (CAR) and N-acetylcysteine (NAC) against NaNO ₂-induced nephrotoxicity in rats. Animals orally received CAR at 100 mg/kg body weight/d for seven days or NAC at 100 mg/kg body weight/d for five days followed by a single oral dose of NaNO ₂ at 60 mg/kg body weight. The rats were killed after 24 hours, and the kidneys were removed and processed for various analyses. NaNO ₂ induced oxidative stress in kidneys, as shown by the decreased activities of antioxidant defense, brush border membrane, and metabolic enzymes. DNA-protein crosslinking and DNA fragmentation were also observed. CAR/NAC pretreatment significantly protected the kidney against these biochemical alterations. Histological studies supported these findings, showing kidney damage in NaNO ₂-treated animals and reduced tissue impairment in the combination groups. The protection offered by CAR and NAC against NaNO ₂-induced damage, and their nontoxic nature, makes them potential therapeutic agents against nitrite-induced nephrotoxicity.     

Spectroscopic and molecular modelling analysis of the interaction between ethane‐1,2‐diyl bis(N,N‐dimethyl‐N‐hexadecylammoniumacetoxy)dichloride and bovine serum albumin

Several spectroscopic approaches namely fluorescence, time‐resolved fluorescence, UV‐visible, and Fourier transform infra‐red (FT‐IR) spectroscopy were employed to examine the interaction between ethane‐1,2‐diyl bis(N,N‐dimethyl‐N‐hexadecylammoniumacetoxy)dichloride (16‐E2‐16) and bovine serum albumin (BSA). Fluorescence studies revealed that 16‐E2‐16 quenched the BSA fluorescence through a static quenching mechanism, which was further confirmed by UV–visible and time‐resolved fluorescence spectroscopy. In addition, the binding constant and the number of binding sites were also calculated. The thermodynamic parameters at different temperatures (298 K, 303 K, 308 K and 313 K) indicated that 16‐E2‐16 binding to BSA is entropy driven and that the major driving forces are electrostatic interactions. Decrease of the α‐helix from 53.90 to 46.20% with an increase in random structure from 22.56 to 30.61% were also observed by FT‐IR. Furthermore, the molecular docking results revealed that 16‐E2‐16 binds predominantly by electrostatic and hydrophobic forces to some residues in the BSA sub‐domains IIA and IIIA. Copyright © 2015 John Wiley & Sons, Ltd.     

Alterations in brush border membrane enzymes,carbohydrate metabolism and oxidative damage to rat intestine by potassium bromate

The acute toxicity of potassium bromate (KBrO₃) on rat small intestine was studied in this work. Animals were given a single oral dose of KBrO₃ (100 mg/kg body weight) and sacrificed 12, 24, 48, 96 and 168 h after the treatment; control animals were not given KBrO₃. The administration of KBrO₃ resulted in a reversible decline in the specific activities of several BBM enzymes. Lipid peroxidation, protein oxidation and hydrogen peroxide levels increased while total sulfhydryl groups and reduced glutathione decreased in KBrO₃-treated rats indicating induction of oxidative stress in the intestinal mucosa. The activities of anti-oxidant and carbohydrate metabolic enzymes were also altered upon KBrO₃ treatment. The maximum changes in all the parameters were 48 h after administration of KBrO₃ after which recovery took place, in many cases almost to control values after 168 h. Histopathological studies supported the biochemical findings showing extensive damage to the intestine at 48 h and recovery at 168 h. These results show that a single oral dose of KBrO₃ causes reversible oxidative damage to the intestine.     

Elevated expression of Rad18 regulates melanoma cell proliferation

The E3 ligase Rad18 is a key regulator for the lesion bypass pathway, which plays an important role in genomic stability. However, the status of Rad18 expression in melanoma is not known. Using melanoma tissue microarray (TMA), we showed that nuclear Rad18 expression was upregulated in primary and metastatic melanoma compared to dysplastic nevi. Rad18 expression was significantly reduced in sun-exposed sites compared to the sun-protected sites. Strong Rad18 expression correlated with worse 5-year patient survival and was an independent prognostic factor for melanoma found in the sun-protected sites. Furthermore, we showed that melanoma cell proliferation and the expression of pAkt and cyclin D1 were reduced upon Rad18 knockdown. We, for the first time, showed that Rad18 is significantly increased in melanoma and predicts the poor outcome for melanoma in the sun-protected sites. Rad18 is involved in the regulation of melanoma cell proliferation, which can be exploited in designing new strategy for melanoma treatment.     

Effect of diallyldisulphide on an antioxidant enzyme system in Candida species

This study was carried out to show the effect of diallyldisulphide (DADS), an important organosulphur compound found in garlic (Allium sativum), on antioxidant systems in Candida species. Changes in antioxidant metabolites and antioxidant activity in the presence of DADS were found in Candida albicans and Candida tropicalis. Candida cells were treated with sublethal concentrations of DADS. DADS caused a decrease in the activity of all antioxidant enzymes except catalase, resulting in oxidative stress and damaged cells. The amount of oxidative stress generated by DADS was found to be a function of its concentration. A significant decrease in superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase activities but an increase in catalase activity were observed. Increased levels of lipid peroxidation and decreased levels of glutathione were observed in treated cells. Activity of glucose-6-phosphate dehydrogenase decreased significantly following DADS treatment and could be correlated with a decrease in glutathione concentration in both Candida species. These results indicate that diallyl disulphide acts as a pro-oxidant to Candida species and hence may act as a potent antifungal in the management of candidiasis.     

Binding of GEF-H1 to the tight junction-associated adaptor cingulin results in inhibition of Rho signaling and G1/S phase transition

The activity of Rho GTPases is carefully timed to control epithelial proliferation and differentiation. RhoA is downregulated when epithelial cells reach confluence, resulting in inhibition of signaling pathways that stimulate proliferation. Here we show that GEF-H1/Lfc, a guanine nucleotide exchange factor for RhoA, directly interacts with cingulin, a junctional adaptor. Cingulin binding inhibits RhoA activation and signaling, suggesting that the increase in cingulin expression in confluent cells causes downregulation of RhoA by inhibiting GEF-H1/Lfc. In agreement, RNA interference of GEF-H1 or transfection of GEF-H1 binding cingulin mutants inhibit G1/S phase transition of MDCK cells, and depletion of cingulin by regulated RNA interference results in irregular monolayers and RhoA activation. These results indicate that forming epithelial tight junctions contribute to the downregulation of RhoA in epithelia by inactivating GEF-H1 in a cingulin-dependent manner, providing a molecular mechanism whereby tight junction formation is linked to inhibition of RhoA signaling.