Response of PRIMPOL-Knockout Human Lung Adenocarcinoma A549 Cells to Genotoxic Stress

Human DNA primase/polymerase PrimPol synthesizes DNA primers de novo after replication fork stalling at the sites of DNA damage, thus contributing to the DNA damage tolerance. The role of PrimPol in response to the different types of DNA damage is poorly understood. We knocked out the PRIMPOL gene in the lung carcinoma A549 cell line and characterized the response of the obtained cells to the DNA damage caused by hydrogen peroxide, methyl methanesulfonate (MMS), cisplatin, bleomycin, and ionizing radiation. The PRIMPOL knockout reduced the number of proliferating cells and cells in the G2 phase after treatment with MMS and caused a more pronounced delay of the S phase in the cisplatin-treated cells. Ionizing radiation at a dose of 10 Gy significantly increased the content of apoptotic cells among the PRIMPOL-deficient cells, while the proportion of cells undergoing necroptosis increased in both parental and knockout cells at any radiation dose. The viability of PRIMPOL-deficient cells upon the hydrogen peroxide-induced oxidative stress increased compared to the control cells, as determined by the methyl tetrazolium (MTT) assay. The obtained data indicate the involvement of PRIMPOL in the modulation of adaptive cell response to various types of genotoxic stress.

Glycoprotein GP as a basis for the universal vaccine against Ebola virus disease

Ebola virus disease (EVD) is one of the deadliest viral infections affecting humans and nonhuman primates. Of 6 known representatives of the Ebolavirus genus responsible for the disease, 3 can infect humans, causing acute highly contagious fever characterized by up to 90% fatality. These include Bundibugyo ebolavirus (BDBV), Zaire ebolavirus (ZEBOV) and Sudan ebolavirus (SUDV). The majority of the reported EVD cases are caused by ZEBOV. Vaccine development against the virus started in 1976, immediately after the causative agent of the infection was identified. So far, 4 vaccines have been approved. All of them are based on the protective epitope of the ZEBOV glycoprotein GP. Because SUDV and BDBV can also cause outbreaks and epidemics, it is vital to design a vaccine capable of conferring protection against all known ebolaviruses posing a threat to the human population. This article presents systematized data on the structure, immunogenicity and protective properties of ebolavirus glycoprotein GP, looks closely at the immunodominant epitopes of ZEBOV, SUDV and BDBV glycoprotein GP required to elicit a protective immune response, and offers a rational perspective on the development of a universal vaccine against EVD that relies on the use of vectors expressing two variants of GP represented by ZEBOV and SUDV.

Thalicosides A1-A3, minor cycloartane bisdesmosides from Thalictrum minus

Three new cycloartane bisdesmosides, two of which are based on a new genin, were isolated from the above-ground parts of Thalictrum minus. Thalicosides A1-A3 (1-3) were characterized as 3-O-beta-D-galactopyranosyl-29-O-beta-D-glucopyranosyl-3beta,16beta++ +, 29-trihydroxy-22(S),25-epoxycycloartane (1); 3-O-alpha-L-arabinopyranosyl-29-O-beta-D-glucopyranosyl-3beta,1 6beta, 29,22(S)-tetrahydroxycycloart-24-ene (2); and 3-O-alpha-L-arabinopyranosyl-29-O-beta-D-glucopyranosyl-3beta,1 6beta, 29-trihydroxy-22(S),25-epoxycycloartane (3), respectively. The structural assignments of these new compounds were based on interpretation of spectroscopic data. Thalicoside A2 showed in vitro inhibition of the fungus Candida albicans and also activity against Staphylococcus aureus.

Squarroside C, a new cycloartene bisdesmoside from Thalictrum squarrosum

Squarroside C (1), a new cycloartane 3,21-bisdesmoside, was isolated from the above-ground parts of Thalictrum squarrosum. The structure of 1 was established as 3-O-[O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranosyl]-21-O-be ta-D-glucopyranosyl-21(S),22(S),23(R),3beta,21alpha,22beta, 30-tetrahydroxy-21,23-epoxycycloart-24-ene by 2D NMR spectroscopy and FABMS.

The elucidation of the structure of thalicoside F, A. minor oleanane glycoside from Thalictrum minus L

A new triterpenoid saponin, thalicoside F was isolated from the above-ground part of Thalictrum minus L. (Ranunculaceae family) collected in Eastern Siberia (Russia). The structure of thalicoside F was elucidated by a combination of 1D- and 2D-NMR spectroscopy and mass spectroscopy, and was determined to be C47H74O17{3-beta-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-(1-->4)-alpha-L-arabinopyranosyl]-11 alpha, 12 alpha-epoxyoleanane-28,13 beta-olide}.