A central paradigm within virology is that each viral particle largely behaves as an independent infectious unit. Here, we demonstrate that clusters of enteroviral particles are packaged within ...phosphatidylserine (PS) lipid-enriched vesicles that are non-lytically released from cells and provide greater infection efficiency than free single viral particles. We show that vesicular PS lipids are co-factors to the relevant enterovirus receptors in mediating subsequent infectivity and transmission, in particular to primary human macrophages. We demonstrate that clustered packaging of viral particles within vesicles enables multiple viral RNA genomes to be collectively transferred into single cells. This study reveals a novel mode of viral transmission, where enteroviral genomes are transmitted from cell-to-cell en bloc in membrane-bound PS vesicles instead of as single independent genomes. This has implications for facilitating genetic cooperativity among viral quasispecies as well as enhancing viral replication.
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•Clusters of viruses are packaged and released non-lytically in PS lipid vesicles•PS lipids are co-factors in mediating subsequent infectivity and transmission•PS vesicles provide greater infection efficiency for viruses•PS vesicles enable viral genome clusters to be transmitted en bloc cell-to-cell
Clusters of enteroviruses are packaged in phosphatidylserine (PS)-enriched vesicles, thereby enhancing the infection efficiency of the viruses and enabling collective transmission of multiple viral genomes from cell-to-cell.
Abstract This work demonstrated the ultra-low fouling natural peptides composed of certain negatively and positively charged residues such as glutamic acid (E) or aspartic acid (D) and lysine (K), in ...the form of either alternating or randomly mixed charge. These peptide-based materials are major candidates as biodegradable nonfouling materials since their final metabolized products are natural amino acids. Although hydrophilic materials can generally reduce nonspecific binding to a certain extent, it is very challenging to achieve ultra-low fouling, which is critical for many biomedical applications, such as medical implants, drug delivery carriers, and biosensors. Based on the design principle of uniformly mixed charges and the selection of appropriate amino acid residues, the natural peptides developed exhibit high resistance to nonspecific protein adsorption (<0.3 ng/cm2 adsorbed proteins) comparable to what is achieved by poly(ethylene glycol) (PEG)-based materials. Mixed charged groups, when uniformly distributed at the molecular level, can achieve ultra-low fouling properties similar to zwitterionic groups due to their strong hydration ability.
The transfer of fresh embryos is generally preferred over the transfer of frozen embryos for in vitro fertilization (IVF), but some evidence suggests that frozen-embryo transfer may improve the ...live-birth rate and lower the rates of the ovarian hyperstimulation syndrome and pregnancy complications in women with the polycystic ovary syndrome.
In this multicenter trial, we randomly assigned 1508 infertile women with the polycystic ovary syndrome who were undergoing their first IVF cycle to undergo either fresh-embryo transfer or embryo cryopreservation followed by frozen-embryo transfer. After 3 days of embryo development, women underwent the transfer of up to two fresh or frozen embryos. The primary outcome was a live birth after the first embryo transfer.
Frozen-embryo transfer resulted in a higher frequency of live birth after the first transfer than did fresh-embryo transfer (49.3% vs. 42.0%), for a rate ratio of 1.17 (95% confidence interval CI, 1.05 to 1.31; P=0.004). Women who underwent frozen-embryo transfer also had a lower frequency of pregnancy loss (22.0% vs. 32.7%), for a rate ratio of 0.67 (95% CI, 0.54 to 0.83; P<0.001), and of the ovarian hyperstimulation syndrome (1.3% vs. 7.1%), for a rate ratio of 0.19 (95% CI, 0.10 to 0.37; P<0.001), but a higher frequency of preeclampsia (4.4% vs. 1.4%), for a rate ratio of 3.12 (95% CI, 1.26 to 7.73; P=0.009). There were no significant between-group differences in rates of other pregnancy and neonatal complications. There were five neonatal deaths in the frozen-embryo group and none in the fresh-embryo group (P=0.06).
Among infertile women with the polycystic ovary syndrome, frozen-embryo transfer was associated with a higher rate of live birth, a lower risk of the ovarian hyperstimulation syndrome, and a higher risk of preeclampsia after the first transfer than was fresh-embryo transfer. (Funded by the National Basic Research Program of China and others; ClinicalTrials.gov number, NCT01841528.).
Supernova (SN) 2009ig was discovered 17 hr after explosion by the Lick Observatory Supernova Search, promptly classified as a normal Type Ia SN (SN Ia), peaked at V = 13.5 mag, and was equatorial, ...making it one of the foremost SNe for intensive study in the last decade. Here, we present ultraviolet (UV) and optical observations of SN 2009ig, starting about 1 day after explosion until around maximum brightness. Our data include excellent UV and optical light curves, 25 premaximum optical spectra, and 8 UV spectra, including the earliest UV spectrum ever obtained of an SN Ia. SN 2009ig is a relatively normal SN Ia, but does display high-velocity ejecta--the ejecta velocity measured in our earliest spectra (v --2,000 km s--1 for Si II Delta *l6355) is the highest yet measured in an SN Ia. The spectral evolution is very dramatic at times earlier than 12 days before maximum brightness, but slows after that time. The early-time data provide a precise measurement of 17.13 ? 0.07 days for the SN rise time. The optical color curves and early-time spectra are significantly different from template light curves and spectra used for light-curve fitting and K-corrections, indicating that the template light curves and spectra do not properly represent all SNe Ia at very early times. In the age of wide-angle sky surveys, SNe like SN 2009ig that are nearby, bright, well positioned, and promptly discovered will still be rare. As shown with SN 2009ig, detailed studies of single events can provide significantly more information for testing systematic uncertainties related to SN Ia distance estimates and constraining progenitor and explosion models than large samples of more distant SNe.
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