The Ulva prolifera genome reveals the mechanism of green tides

The genome of green microalgae has rarely been reported.Ulva prolifera is a green microalga that has received much attention.Despite research articles about U.prolifera in recent years,we know very little about its genome.Therefore,the 87.9-Mb haploid genome(containing 10311 protein-coding genes)of U.prolifera was studied,and the genome was compared with that of U.mutabilis,which is the only published Ulva species.Results showed that the two species are closely related.A phylogenetic tree was constructed among U.prolifera and other green algae available in GenBank,revealing the evolutionary status of U.prolifera in Chlorophyta.To understand why U.prolifera could grow rapidly,we identified some genes related to growth,such as those involved in cell division,phosphorylation,and cell proliferation.In addition,genes related to stress resistance were found,which supports the notion that U.prolifera grows vigorously in nature.These results help to characterize green tides from a new perspective and reveal some important insight into the biology of U.prolifera.

Characterization of SARS-COV-2 main protease inhibitory peptides from Ulva prolifera proteins

The main protease(M^(pro))is essential for the replication of SARS-COV-2 and therefore represents a promising anti-viral target.In this study,we screened M^(pro)inhibitory peptides from Ulva prolifera protein on in-silico proteolysis.Cytotoxicity analysis using the online toxic prediction tool ToxinPred revealed that all the peptides were non-cytotoxic.The hexapeptide(SSGFID)exhibited high M^(pro)inhibitory activity in molecular docking and its IC_(50)value was 139.40±0.82μmol/L in vitro according to fluorescence resonance energy transfer assay(FRET).Quantitative real-time(qRT-)PCR results show that SSGFID could stimulate the expression of mitosis-related factors,including nuclear factor-κB,cyclin D1,and cyclin-dependent kinase 4,to promote the proliferation of mice splenocytes.Stability study revealed that SSGFID showed resistance against pepsin and trypsin but lost D(Asp)after pretreatment at121℃ for 15 min.Besides,SSGFID was mainly transported through the Caco-2 cell monolayer by the peptide transporter PepT1 and passive-mediated transport during the transport study.Unfortunately,the peptide was also degraded by Caco-2 intracellular enzymes,and the transfer rate of intact peptide was4.2%.Furthermore,Lineweaver–Burk plots demonstrated that SSGFID possessed a mixed inhibitory characteristic with M^(pro).Our study indicated the potential of Ulva prolifera as antiviral and immuneenhancing functional food ingredients and nutraceuticals.

Pay-it-forward gonorrhea and chlamydia testing among men who have sex with men in China:a study protocol for a three-arm cluster randomized controlled trial

Background:Gonorrhea and chlamydia testing rates are poor among Chinese men who have sex with men(MSM).A quasi-experimental study suggested that a pay-it-forward strategy increased dual gonorrhea/chlamydia testing among MSM.Pay-it-forward offers an individual a gift(e.g.,a free test)and then asks the same person if they would like to give a gift to another person.This article reports the protocol of a randomized controlled trial to evaluate dual gonorrhea/chlamydia test uptake and other outcomes among MSM in three arms-a pay-it-forward arm,a pay-what-you-want arm,and a standard of care arm.Methods:Three hundred MSM will be recruited at three HIV testing sites in Guangzhou and Beijing.Testing sites include two hospital-based MSM sexually transmitted diseases clinics and one MSM community-based organization.Eligible participants will be born biologically male,aged 16 years or older,reporting previous anal sex with another man,having never participated in the pay-it-forward program,without previous gonorrhea and chlamydia testing in the past 12 months,and residing in China.Following a cluster randomized design,every cluster of ten participants will be randomly allocated into one of three arms:(1)a pay-it-forward arm in which men are offered free gonorrhea and chlamydia testing and then asked whether they would like to donate("pay it forward")toward testing for future testers;(2)a pay-what-you-want arm in which men are offered free testing and told to decide how much to pay after receiving the test;(3)a standard of care arm in which men can pay the full price for dual gonorrhoea and chlamydia testing.The primary outcome is dual gonorrhoea/chlamydia testing as verified by administrative records.Secondary outcomes include incremental cost per test,incremental cost per diagnosis,community connectedness,and social cohesion.Primary outcome will be calculated for each arm using intention-to-treat and compared using one-sided 95%confidence intervals with a margin of 20%increase defined as superiority.Discussion:This study will examine the pay-it-forward strategy in comparison to the standard of care in improving test uptake for gonorrhea and chlamydia.We will leverage the cluster randomized controlled trial to provide scientific evidence on the potential effect of pay-it-forward.Findings from this study will shed light on novel intervention methods for increasing preventive health service utilization and innovate ways to finance it among communities.Trial registration:ClinicalTrials.gov,NCT03741725.Registered on 12 November 2018.