In this study, paclitaxel (PTX)-loaded pH-responsive niosomes modified with ergosterol were developed. This new formulation was characterized in terms of size, morphology, encapsulation efficiency (EE), and in vitro release at pH 5.2 and 7.4. The in vitro efficacy of free PTX and niosome/PTX was assessed using MCF7, Hela, and HUVEC cell lines. In order to evaluate the in vivo efficacy of niosomal PTX in rats as compared to free PTX, the animals were intraperitoneally administered with 2.5 mg/kg and 5 mg/kg niosomal PTX for two weeks. Results showed that the pH-responsive niosomes had a nanometric size, spherical morphology, 77% EE, and pH-responsive release in pH 5.2 and 7.4. Compared with free PTX, we found markedly lower IC50s when cancer cells were treated for 48 h with niosomal PTX, which also showed high efficacy against human cancers derived from cervix and breast tumors. Moreover, niosomal PTX induced evident morphological changes in these cell lines. In vivo administration of free PTX at the dose of 2.5 mg/kg significantly increased serum biochemical parameters and liver lipid peroxidation in rats compared to the control rats. The situation was different when niosomal PTX was administered to the rats: the 5 mg/kg dosage of niosomal PTX significantly increased serum biochemical parameters, but the group treated with the 2.5 mg/kg dose of niosomal PTX showed fewer toxic effects than the group treated with free PTX at the same dosage. Overall, our results provide proof of concept for encapsulating PTX in niosomal formulation to enhance its therapeutic efficacy.

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Purpose The COVID-19 disease with acute respiratory symptoms emerged in 2019. The causal agent of the disease, the SARS-CoV-2 virus, is classified into the Betacoronaviruses family. Coronaviruses (CoVs) are a huge family of viruses. Therefore, homologous recombination studies can help recognize the phylogenetic relationships among these viruses. Methods In order to detect possible recombination events in SASRS-CoV-2, the genome sequences of Betacoronaviruses were obtained from the GenBank. The nucleotide sequences with the identity ≥ 60% to SARS-CoV-2 genome sequence were selected and then analyzed using different algorithms. Results The results showed two recombination events at the beginning and the end of the genome sequence of SARS-CoV-2. Bat-SL-CoVZC21 (GenBank accession number MG772934) was specified as the minor parent for both events with p-values of 8.66 × 10 –87 and 3.29 × 10 –48 , respectively. Furthermore, two recombination regions were detected at the beginning and the middle of the SARS-CoV-2 spike gene. Pangolin-CoV (PCoV_GX-P4L) and Rattus CoV (ChRCoV-HKU24) were determined as the potential parents with the GenBank accession number MT040333 and KM349742, respectively. Analysis of the spike gene revealed more similarity and less nucleotide diversity between SARS-CoV-2 and pangolin-CoVs. Conclusion Detection of the ancestors of SARS-CoV-2 in the coronaviruses family can help identify and define the phylogenetic relationships of the family Coronaviridae. Furthermore, constructing a phylogenetic tree based on the recombination regions made changes in the phylogenetic relationships of Betacoronaviruses. Supplementary Information The online version contains supplementary material available at 10.1007/s10529-021-03218-7.

The thermal sensitivity of firefly luciferase limits its use in certain applications. Firefly luciferase has hydrophobic sites on its surface, which lead to aggregation and inactivation of the enzyme at temperatures over 30°C. We have successfully stabilized firefly luciferase at high temperatures with the assistance of a unique protein, hydrophobin-1 (HFB1). HFB1 is a small secretory protein belonging to class II of hydrophobins with a low molecular weight (7.5 kDa) and distinct functional hydrophobic patch on its surface. The interaction of HFB1 with hydrophobic sites on the surface of luciferase was confirmed by extrinsic fluorescence studies using 8-anilino-1-naphthalenesulfonic acid (ANS) as a hydrophobic reporter probe. Calculation of thermodynamic parameters of heat inactivation of luciferase shows that conformational changes and flexibility of enzyme decreased in the presence of HFB1, and thermostability of the HFB1-treated enzyme increased. Furthermore, the addition of HFB1 into the enzymatic solution leads to an increase in catalytic efficiency of luciferase and subsequently improves the utility of the enzyme as an ATP detector.