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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Andrews, Jennifer E., et al.
(författare)
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SN 2017gmr : An Energetic Type II-P Supernova with Asymmetries
- 2019
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 885:1
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Tidskriftsartikel (refereegranskat)abstract
- We present high-cadence UV, optical, and near-infrared data on the luminous Type II-P supernova SN;2017gmr from hours after discovery through the first 180 days. SN;2017gmr does not show signs of narrow, high-ionization emission lines in the early optical spectra, yet the optical light-curve evolution suggests that an extra energy source from circumstellar medium (CSM) interaction must be present for at least 2 days after explosion. Modeling of the early light curve indicates a ?500 R progenitor radius, consistent with a rather compact red supergiant, and late-time luminosities indicate that up to 0.130;;0.026 M of Ni-56 are present, if the light curve is solely powered by radioactive decay, although the Ni-56 mass may be lower if CSM interaction contributes to the post-plateau luminosity. Prominent multipeaked emission lines of H? and [O i] emerge after day 154, as a result of either an asymmetric explosion or asymmetries in the CSM. The lack of narrow lines within the first 2 days of explosion in the likely presence of CSM interaction may be an example of close, dense, asymmetric CSM that is quickly enveloped by the spherical supernova ejecta.
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| 3. |
- Feng, Ruizhi, et al.
(författare)
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Mutations in TUBB8 and Human Oocyte Meiotic Arrest.
- 2016
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Ingår i: The New England journal of medicine. - 1533-4406. ; 374:3, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- Background Human reproduction depends on the fusion of a mature oocyte with a sperm cell to form a fertilized egg. The genetic events that lead to the arrest of human oocyte maturation are unknown. Methods We sequenced the exomes of five members of a four-generation family, three of whom had infertility due to oocyte meiosis I arrest. We performed Sanger sequencing of a candidate gene, TUBB8, in DNA samples from these members, additional family members, and members of 23 other affected families. The expression of TUBB8 and all other β-tubulin isotypes was assessed in human oocytes, early embryos, sperm cells, and several somatic tissues by means of a quantitative reverse-transcriptase-polymerase-chain-reaction assay. We evaluated the effect of the TUBB8 mutations on the assembly of the heterodimer consisting of one α-tubulin polypeptide and one β-tubulin polypeptide (α/β-tubulin heterodimer) in vitro, on microtubule architecture in HeLa cells, on microtubule dynamics in yeast cells, and on spindle assembly in mouse and human oocytes. Results We identified seven mutations in the primate-specific gene TUBB8 that were responsible for oocyte meiosis I arrest in 7 of the 24 families. TUBB8 expression is unique to oocytes and the early embryo, in which this gene accounts for almost all the expressed β-tubulin. The mutations affect chaperone-dependent folding and assembly of the α/β-tubulin heterodimer, disrupt microtubule behavior on expression in cultured cells, alter microtubule dynamics in vivo, and cause catastrophic spindle-assembly defects and maturation arrest on expression in mouse and human oocytes. Conclusions TUBB8 mutations have dominant-negative effects that disrupt microtubule behavior and oocyte meiotic spindle assembly and maturation, causing female infertility. (Funded by the National Basic Research Program of China and others.).
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| 4. |
- Feng, Ruizhi, et al.
(författare)
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MiRNA-320 in the human follicular fluid is associated with embryo quality in vivo and affects mouse embryonic development in vitro.
- 2015
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Previous work from our laboratory demonstrated the existence of miRNAs in human follicular fluid. In the current study, we have sought to identify miRNAs that might affect oocyte/embryo quality in patients undergoing intracytoplasmic sperm injection and to investigate their roles in in vitro fertilization outcomes in mouse oocytes. 53 samples were classified as Group 1 (high quality) if the day-3 embryos had seven and more cells or as Group 2 (low quality) if the embryos had six and fewer cells. TaqMan Human microRNAs cards and qRT-PCR were performed to verify differently expressed miRNAs. The function of the corresponding miRNA was investigated in mouse oocytes by injecting them with miRNA-inhibitor oligonucleotides. We found that hsa-miR-320a and hsa-miR-197 had significantly higher expression levels in the Group 1 follicular fluids than in Group 2 (p = 0.0073 and p = 0.008, respectively). Knockdown of mmu-miR-320 in mouse oocytes strongly decreased the proportions of MII oocytes that developed into two-cell and blastocyst stage embryos (p = 0.0048 and p = 0.0069, respectively). Wnt signaling pathway components had abnormal expression level in miR-320 inhibitor-injected oocytes. This study provides the first evidence that miRNAs in human follicular fluid are indicative of and can influence embryo quality.
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| 5. |
- Liu, Fei, et al.
(författare)
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Draft genomes of four enterotoxigenic Escherichia coli (ETEC) clinical isolates from China and Bangladesh
- 2015
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Ingår i: Gut Pathogens. - : Springer Science and Business Media LLC. - 1757-4749. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- © 2015 Liu et al. Abstract Background: Enterotoxigenic Escherichia coli (ETEC) is an important pathogen that causes childhood and travelers' diarrhea. Here, we present the draft genomes of four ETEC isolates recovered from stool specimens of patients with diarrhea in Beijing, China and Dhaka, Bangladesh, respectively. Results: We obtained the draft genomes of ETEC strains CE516 and CE549 isolated in China, and E1777 and E2265 isolated in Bangladesh with a length of 5.1 Mbp, 4.9 Mbp, 5.1 Mbp, and 5.0 Mbp, respectively. Phylogenetic analysis indicated that the four strains grouped with the classical Escherichia coli phylogenetic groups A and B1 and three of them including a multi drug-resistant Chinese isolate (CE549) belonged to two major ETEC lineages distributed globally. The heat stable toxin (ST) structural gene (estA) was present in all strains except in strain CE516, and the heat labile toxin (LT) operon (eltAB) was present in all four genomes. Moreover, different resistance gene profiles were found between the ETEC strains. Conclusions: The draft genomes of the two isolates CE516 and CE549 represent the first genomes of ETEC reported from China. Though we revealed that ETEC is uncommon in Beijing, China, however, when it does occur, multi-drug resistance and ESBL positive isolates might pose a specific public health risk. Furthermore, this study advances our understanding of prevalence and antibiotic resistance of ETEC in China and adds to the number of sequenced strains from Bangladesh.
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| 6. |
- Yin, Huijuan, et al.
(författare)
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Photodynamic therapy targeting VCAM-1-expressing human umbilical vein endothelial cells using a PpIX-VCAM-1 binding peptide-quantum dot conjugate
- 2017
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Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 7:80, s. 50562-50570
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Tidskriftsartikel (refereegranskat)abstract
- With increasing knowledge of the relevance of vascular cell adhesion molecule 1 (VCAM-1) for tumor growth, metastasis, angiogenesis, and related processes, it has become an attractive anti-tumor strategy to target VCAM-1 expression on the tumor vasculature. We designed a new targeted nanodrug, denoted PVQ, based on a photosensitizer (for the photodynamic effect), VCAM-1 target and quantum dot (QD) carrier, using conjugated water-dispersible colloidal CdSe-CdS/ZnS QDs, protoporphyrin IX (PpIX) photosensitizers, and VCAM-1 binding peptides. Its targeting ability and photodynamic therapy (PDT) efficiency against VCAM-1 expression in human umbilical vein endothelial cells (HUVECs) were then investigated. Conjugates of QD-VCAM-1 binding peptide (VQ), PpIX-VCAM-1 binding peptide (PV), and PVQ prepared using amide coupling were verified by agarose gel electrophoresis, Fourier transform infrared spectroscopy, and fluorescence spectrometry. VCAM-1 expression in HUVECs was induced by TNF-alpha treatment. PVQ conjugates were co-cultured with VCAM-1 expressing (VCAM-1(+)) and non-expressing (VCAM-1(-)) HUVECs, and target imaging, ROS generation, cell death, and apoptosis were analyzed using confocal fluorescence microscopy. VCAM-1 target imaging could not distinguish between VCAM-1(+) and VCAM-1(-) HUVECs after only 6 h of incubation; however it could distinguish between the cells after incubation for 24 h. After incubation for ca. 30 min, PVQ generated a significantly higher yield of ROS (3.6 fold) in VCAM-1(+) HUVECs compared with VCAM-1(-) cells, during 10 min of irradiation at a wavelength of 405 nm, and this was followed by a second rise in ROS at 30 min after irradiation. Moreover, cell destruction was observed clearly in VCAM-1(+) cells treated with PVQ and almost all cells became round after 30 min of irradiation at 405 nm. PVQ-induced PDT effects caused a significant apoptosis (onset and late apoptosis) in VCAM-1(+) HUVECs at 6 h after PDT treatment. In conclusion, PVQ shows a great potential for targeted PDT in cancer therapy.
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