Infectivity and antigenicity of pseudoviruses with high-frequency mutations of SARS-CoV-2 identified in Portugal.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a major impact on global human health. During the spread of SARS-CoV-2, weakened host immunity and the use of vaccines with low efficacy may result in the development of more-virulent strains or strains with resistance to existing vaccines and antibodies. The prevalence of SARS-CoV-2 mutant strains differs between regions, and this variation may have an impact on the effectiveness of vaccines. In this study, an epidemiological investigation of SARS-CoV-2 in Portugal was performed, and the VSV-ΔG-G* pseudovirus system was used to construct 12 spike protein epidemic mutants, D614G, A222V+D614G, B.1.1.7, S477N+D614G, P1162R+D614G+A222V, D839Y+D614G, L176F+D614G, B.1.1.7+L216F, B.1.1.7+M740V, B.1.258, B.1.258+L1063F, and B.1.258+N751Y. The mutant pseudoviruses were used to infect four susceptible cell lines (Huh7, hACE2-293T-293T, Vero, and LLC-MK2) and 14 cell lines overexpressing ACE2 from different species. Mutant strains did not show increased infectivity or cross-species transmission. Neutralization activity against these pseudoviruses was evaluated using mouse serum and 11 monoclonal antibodies. The neutralizing activity of immunized mouse serum was not significantly reduced with the mutant strains, but the mutant strains from Portugal could evade nine of the 11 monoclonal antibodies tested. Neutralization resistance was mainly caused by the mutations S477N, N439K, and N501Y in the spike-receptor binding domain. These findings emphasize the importance of SARS-CoV-2 mutation tracking in different regions for epidemic prevention and control.

[Establishment of AML Mouse Model by Transplantation of Hematopoietic Cells from MLL-AF9 Transgenic Mice].

OBJECTIVE: To establish a leukemia mouse model induced by transplantation of hematopoietic cells from mixed lineage leukemia (MLL)-AF9 transgenic mice so as to provide the basis for the mechanism research and drug screening of acute myeloid leukemia (AML). METHODS: MLL-AF9 knock-in mice were bred and identified. When the mice developed leukemia, white blood cell (WBC) count in peripheral blood, flow cytometry and morphology method were analyzed to identify the disease. When the WBC count in peripheral blood was more than 100×109/L, bone marrow cells and spleen cells were collected and cryopresevated. After resuscitation, the cells were injected into 4.5 Gy irradiated wild C57BL/6J mice through the tail vein to develop MLL-AF9 leukemia mouse model. Finally, the therapeutic effect was evaluated by positive drug on the model. RESULTS: The natural onset times of leukemia on MLL-AF9 knock-in mice were 22-28 weeks. The spleens of the transgenic mice enlarged and the bone marrow showed the immature forms of myeloid leukemia cells. Both the bone marrow and spleen cells highly expressed myeloid markers, CD11b and Gr-1. At least 0.5×106 bone marrow cells and 2.5×106 spleen cells could induce leukemia in all recipient mice, and the median survival times of mice were 20 days and 36 days, respectively. Experimental treatment was carried out on the leukemia mouse model transplanted with MLL-AF9 spleen cells, and it was found that the traditional chemotherapy drug cytarabine could delay the onset of leukemia and prolong the survival time of the mouse model. CONCLUSION: The leukemia model of hematopoietic cell transplantation based on MLL-AF9 transgenic mice is successfully established, which can be used for the study of the pathogenesis and evaluation of therapeutic effect of AML.

Three new secolignan glycosides from Urtica fissa E. Pritz.

Three new secolignan glycosides {3,4-trans-4-[bis(3,4-dimethoxyphenyl)methyl]-2-oxotetrahydrafuran-3-yl}methyl-O-ß-glucopyranoside (1), {3,4-trans-4-[(3-methoxy-4-hydroxyphenyl)(3,4-dimethoxyphenyl)methyl]-2-oxotetrahydrafuran-3-yl}methyl-O-ß-glucopyranoside (2) and {3,4-cis-4-[(3-methoxy-4-hydroxyphenyl)(3,4-dimethoxyphenyl)methyl]-2-oxotetrahydrafuran-3-yl}methyl-O-ß-glucopyranoside (3) were isolated from the roots of Urtica fissa E. Pritz. Their structures were identified by spectral methods including 1D NMR, 2D NMR and HR-EI-MS.

Two new 3-oxo-α-ionol glucosides from Urtica laetevirens Maxim.

Two new 3-oxo-α-ionol glucoside isomers, (6R,9R)-3-oxo-α-ionol-9-O-ß-D-glucopyranosyl (1 → 2)-ß-D-glucopyranoside (1) and (6S,9R)-3-oxo-α-ionol-9-O-ß-D-glucopyranosyl (1 → 2)-ß-D-glucopyranoside (2) were isolated from the aerial parts of Urtica laetevirens Maxim. Their structures, including stereochemistry, were established by spectral analyses (HR-ESI-MS, NMR and CD). Also, 3-oxo-α-ionol glucosides were isolated from Urtica species for the first time.

[Synthesis of seven sinapine analogs and their effects on the tension of smooth muscle of intestines isolated from rabbit].

Seven sinapine analogs (6a-6g) were synthesized using cinnamon acid or benzoic acid and their derivatives as starting materials, which obtained from substituted benzaldehyde and malonate. The structures of target compounds were characterized by IR, 1H NMR and elemental analysis. The effects of compounds 6a-6g on the smooth muscle of intestine isolated from rabbit were studied, and the experimental results showed that compounds 6a, 6d and 6g had diastolic action, while 6f had contractile action.