Assessment of thermal and temporal stability of SARS-CoV-2 samples using real-time qRT-PCR

BACKGROUND

As per the guidelines of the Indian Council of Medical Research, nasopharyngeal and oropharyngeal swabs in viral transport medium (VTM) are to be stored at 4 °C for less than 5 days and for more than 5 days at -70 °C. Samples are not transported or stored as per prescribed conditions because of the limitations, resulting in an apprehensive diagnosis. The aim of the study was to test the stability of the SARS-CoV-2 sample stored in VTM at different temperatures.

METHODS

In this study, the stability of 21 positive and 9 negative samples for SARS-CoV-2 was evaluated in commercial VTM at different temperatures (-80 °C, -20 °C, 4 °C, and 25 to 30 °C). Stability was checked for up to 50 days in the above storage conditions at different intervals. PathoDetect™ and Hi-PCR® kits were used for the detection of the four genes of SARS-CoV-2. The Cycle Threshold (Ct) value for determining the positivity of samples for PathoDetect™ was < 40 and for Hi-PCR® was < 38.

RESULTS

The SARS-CoV-2 confirmatory genes (RdRp and E genes) and the internal housekeeping gene remained detectable even on the 50th day of the study. The Ct of the RdRp and E genes were found to increase with storage duration, but all positive samples remained positive till the end of the study, or the Ct value remained below the cut-off level. The negative samples gave consistent results until the end of the study. When the differences in Ct values were compared between the days in a set of experiments, they were not significantly different except in a few samples.

CONCLUSION

The SARS-CoV-2 genetic materials in commercial VTM were stable at room temperature to -80 °C for 50 days.

Supplementation of nano-selenium (SeNPs) improved growth, immunity, antioxidant enzyme activity, and selenium retention in broiler chicken during summer season

The present experiment was aimed at finding the optimal supplemental dose of nano-selenium in broiler chicken during the summer season for better performance in terms of growth, blood metabolites, immune response, antioxidant status, and selenium concentration in vital organs. Three-hundred-day-old Vencobb broiler chicks were randomly distributed into five dietary treatment groups with six replicates of 10 chicks each. The dietary treatments were as follows: T1 (control group), basal diet; T2, basal diet with 0.0375 ppm of nano-Se; T3, basal diet with 0.075 ppm of nano-Se; T4, basal diet with 0.15 ppm of nano-Se; T5, basal diet with 0.3 ppm of nano-Se. The experiment was carried out for 35 days. The average gain and feed conversion ratio were best observed in T4 and T5. The antibody titres were significantly higher (P < 0.05) in the treated birds. At the 5th week, erythrocytic glutathione peroxidase, catalase, and superoxide dismutase activities were significantly (P < 0.05) higher and lipid peroxidation values were significantly (P < 0.05) lower in all the nano-Se-treated groups. The Se levels in the liver, breast muscle, kidney, brain, and gizzard were significantly (P < 0.05) increased with increased dietary nano-Se. Histological studies of the liver and kidney in the highest nano-Se-treated groups (T4 and T5) did not show any abnormal changes. It is concluded that supplementation of nano-selenium at 0.15 ppm over and above the basal level improved the performance and protect the birds from summer stress without any adverse effect on the vital organs of chicken.

Comparative evaluation of hormonal protocol on the performance of crossbred cattle

A total of 60 animals (38 cows, 22 heifers) were selected and were divided into three groups of 20 animals each (containing both anoestrus and repeat breeder) in which treatment was performed for 60 days. Group I: control (farmer practice), T₁ group: group I + hormone (double synch), and T₂ group: group I + hormone (Estra double synch). The growth performances were measured in terms of body weight and average daily gain (ADG). Blood collection was done at the start and end of the experiment for assessment of blood biochemical, hematological, and reproductive status of the animals. Results revealed significant improvement in growth and reproductive performances in treatment group as compared to control group. Higher percentage of conception was achieved in group III (60%) followed by group II (55%). The least percentage was in group I (15%), i.e., in control group. So it was found that the effect of treating the reproductive-disordered animals with Estra double synch gave comparatively better result than double synch hormonal application.

Frizzled-7 signalling controls tissue separation during Xenopus gastrulation

Cell signalling through Frizzled receptors has evolved to considerable complexity within the metazoans. The Frizzled-dependent signalling cascade comprises several branches, whose differential activation depends on specific Wnt ligands, Frizzled receptor isoforms and the cellular context. In Xenopus laevis embryos, the canonical beta-catenin pathway contributes to the establishment of the dorsal-ventral axis. A different branch, referred to as the planar cell polarity pathway, is essential for cell polarization during elongation of the axial mesoderm by convergent extension. Here we demonstrate that a third branch of the cascade is independent of Dishevelled function and involves signalling through trimeric G proteins and protein kinase C (PKC). During gastrulation, Frizzled-7 (Fz7)-dependent PKC signalling controls cell-sorting behaviour in the mesoderm. Loss of zygotic Fz7 function results in the inability of involuted anterior mesoderm to separate from the ectoderm, which leads to severe gastrulation defects. This result provides a developmentally relevant in vivo function for the Fz/PKC pathway in vertebrates.

Functional analysis of the Xenopus frizzled 7 protein domains using chimeric receptors

Seven-transmembrane receptors of the frizzled family can interact with secreted Wnt ligands and transmit Wnt signals into the cell. Dependent on the ligand receptor combination, distinct Wnt pathways are activated. Xenopus frizzled 7 (Xfz7) and Xwnt-8b as well as Human frizzled 5 (Hfz5) and Xwnt-5a can act synergistically in the activation of Wnt/beta-catenin target genes siamois (Xsia) and nodal related 3 (Xnr3) and in the induction of ectopic axes in Xenopus embryos. In order to characterize the role of different protein domains of Xfz7 in Wnt/beta-catenin signaling, chimeric Xfz7/Hfz5 receptors were generated in which the extracellular (N5-TC7) or the intracellular domains (NT7-C5) between Xfz7 and Hfz5 were exchanged. We present evidence that the extracellular domain of Xfz7 can interact with Xwnt-5a and that the intracellular C-terminus can transmit a Wnt/beta-catenin signal. Despite these abilities, Xfz7 and Xwnt-5a do not act synergistically in the activation of Wnt/beta-catenin targets. This implies that the interaction of a frizzled receptor with different ligands can result in distinct cellular responses.

P-glycoprotein is positively correlated with p53 in human oral pre-malignant and malignant lesions and is associated with poor prognosis

P-glycoprotein (Pgp) encoded by the MDR1 gene, a predictor of chemoresistance, may also serve as a prognosticator of clinical outcome in cancer patients. The mutant tumour-suppressor p53 protein has been shown to activate the MDR1 promoter, whereas the wild-type p53 represses this activity in cultured cells. We have described the differential expression of Pgp and p53 proteins in betel- and tobacco-related oral tumorigenesis in the Indian population. Herein, Pgp expression was analysed in relation to p53 protein accumulation in pre-malignant and malignant oral lesions by immunohistochemical and flow-cytometric analyses. The relationship between Pgp and p53 protein accumulation and clinicopathological parameters as well as prognosis was determined. Expression of Pgp was observed in 81% of oral squamous cell carcinomas (SCCs) and 71% of pre-malignant lesions. Sixty-five of 75 p53-positive oral SCCs and 21/24 p53-positive pre-malignant lesions showed expression of Pgp. Significant correlation between Pgp and p53 expression was found not only in oral SCCs but also in pre-malignant lesions. Co-expression of Pgp and p53 proteins was indicative of poor prognosis. Follow-up studies of 35 patients showed that 7 of 10 oral SCCs with accumulation of Pgp and p53 proteins also exhibited shorter disease-free survival (recurrence/metastases). Our findings provide clinical evidence for a significant association between Pgp and p53 protein expression in oral tumorigenesis and may account for the aggressive nature of the tumour and poor prognosis.