Chitosan-catalyzed n-butyraldehyde self-condensation reaction mechanism and kinetics

The chitosan was found to possess an excellent catalytic performance in n-butyraldehyde selfcondensation to 2 E2 H.Under suitable conditions,the conversion of n-butyraldehyde,the yield and selectivity of 2 E2 H separately attained 96.0%,86.0%and 89.6%.The chitosan catalyst could be recovered and used for 5 times without a significant deactivation after being treated with ammonium hydroxide.In order to elucidate the reaction mechanism,the adsorption and desorption of n-butyraldehyde on the surface of chitosan were studied using in situ FT-IR spectroscopy analysis.The result showed that n-butyraldehyde interacts with\\NH2 group of chitosan to form an intermediate species with an enamine structure.Then the reaction process of n-butyraldehyde self-condensation was monitored by React-IR technique and it was found that n-butyraldehyde self-condensation to 2-ethyl-3-hydroxyhexanal followed by a dehydration reaction to 2-ethyl-2-hexenal.On this basis,chitosan-catalyzed n-butyraldehyde self-condensation reaction mechanism was speculated and its reaction kinetics was investigated.The self-condensation reaction follows auto-catalytic reaction characteristics and then the corresponding kinetic model was established.

Multiomics comparison among populations of three plant sources of Amomi Fructus

Amomi Fructus(Sharen,AF)is a traditional Chinese medicine(TCM)from three source species(or varieties),including Wurfbainia villosa var.villosa(WVV),W.villosa var.xanthioides(WVX),or W.longiligularis(WL).Among them,WVV has been transplanted from its top-geoherb region,Guangdong,to its current main production area,Yunnan,for>50 years in China.However,the genetic and transcriptomic differentiation among multiple AF source species(or varieties)and between the origin and transplanted populations of WVV is unknown.In our study,the observed overall higher expression of terpenoid biosynthesis genes in WVV than in WVX provided possible evidence for the better pharmacological effect of WVV.We also screened six candidate borneol dehydrogenases(BDHs)that potentially catalyzed borneol into camphor in WVV and functionally verified them.Highly expressed genes at the P2 stage of WVV,Wv05G1424 and Wv05G1438,were capable of catalyzing the formation of camphor from(+)-borneol,(-)-borneol and DL-isoborneol.Moreover,the BDH genes may experience independent evolution after acquiring the ancestral copies,and the following tandem duplications might account for the abundant camphor content in WVV.Furthermore,four populations of WVV,WVX,and WL are genetically differentiated,and the gene flow from WVX to WVV in Yunnan contributed to the greater genetic diversity in the introduced population(WVV-JH)than in its top-geoherb region(WVV-YC),which showed the lowest genetic diversity and might undergo genetic degradation.In addition,terpene synthesis(TPS)and BDH genes were selected among populations of multiple AF source species(or varieties)and between the top-and non-top-geoherb regions,which might explain the difference in metabolites between these populations.Our findings provide important guidance for the conservation,genetic improvement,and industrial development of the three source species(or varieties)and for identifying top-geoherbalism with molecular markers,and proper clinical application of AF.

采后UV-C辐照对番茄果实基因表达谱的短时效应

利用美国昂飞公司的番茄基因芯片进行微阵列分析,从而对经UV-C(4 kJ/m2)辐照后贮藏24 h内的番茄果实中的基因表达情况作出全面概括。结果表明,经UV-C辐照的番茄果实中分别有274和403个基因发生了基因上调和下调,比对照果实高出两倍多。发生上调的基因主要涉及到信号转导、防御反应及生理代谢功能;与之相反,一些涉及到细胞壁降解、光合作用及脂类代谢功能的基因则普遍发生基因下调。本研究结果从分子机制的角度阐述了采后UV-C辐照使番茄果实抗病性增强、延迟软化、维持采后品质及延长贮期的原因。

Diel dynamics of multi-omics in elkhorn fern provide new insights into weak CAM photosynthesis

Crassulacean acid metabolism(CAM)has high water-use efficiency(WUE)and is widely recognized to have evolved from C3 photosynthesis.Different plant lineages have convergently evolved CAM,but the molecular mechanism that underlies C3-to-CAM evolution remains to be clarified.Platycerium bifurcatum(elkhorn fern)provides an opportunity to study the molecular changes underlying the transition from C3 to CAM photosynthesis because both modes of photosynthesis occur in this species,with sporotrophophyll leaves(SLs)and cover leaves(CLs)performing C3 and weak CAM photosynthesis,respectively.Here,we report that the physiological and biochemical attributes of CAM in weak CAM-performing CLs differed from those in strong CAM species.We investigated the diel dynamics of the metabolome,proteome,and transcriptome in these dimorphic leaves within the same genetic background and under identical environmental conditions.We found that multi-omic diel dynamics in P.bifurcatum exhibit both tissue and diel effects.Our analysis revealed temporal rewiring of biochemistry relevant to the energy-producing pathway(TCA cycle),CAM pathway,and stomatal movement in CLs compared with SLs.We also confirmed that PHOSPHOENOLPYRUVATE CARBOXYLASE KINASE(PPCK)exhibits convergence in gene expression among highly divergent CAM lineages.Gene regulatory network analysis identified candidate transcription factors regulating the CAM pathway and stomatal movement.Taken together,our results provide new insights into weak CAM photosynthesis and new avenues for CAM bioengineering.

Weak SARS-CoV-2-specific responses of TIGIT-expressing CD8^(+)T cells in people living with HIV after a third dose of a SARS-CoV-2 inactivated vaccine

Background:T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains(TIGIT),an inhibitory receptor expressed on T cells,plays a dysfunctional role in antiviral infection and antitumor activity.However,it is unknown whether TIGIT expression on T cells influences the immunological effects of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)inactivated vaccines.Methods:Forty-five people living with HIV(PLWH)on antiretroviral therapy(ART)for more than two years and 31 healthy controls(HCs),all received a third dose of a SARS-CoV-2 inactivated vaccine,were enrolled in this study.The amounts,activation,proportion of cell subsets,and magnitude of the SARS-CoV-2-specific immune response of TIGIT^(+)CD4^(+)and TIGIT^(+)CD8^(+)T cells were investigated before the third dose but 6 months after the second vaccine dose(0W),4 weeks(4W)and 12 weeks(12W)after the third dose.Results:Compared to that in HCs,the frequency of TIGIT^(+)CD8^(+)T cells in the peripheral blood of PLWH increased at 12W after the third dose of the inactivated vaccine,and the immune activation of TIGIT^(+)CD8^(+)T cells also increased.A decrease in the ratio of both T naïve(T_(N))and central memory(T_(CM))cells among TIGIT^(+)CD8^(+)T cells and an increase in the ratio of the effector memory(T_(EM))subpopulation were observed at 12W in PLWH.Interestingly,particularly at 12W,a higher proportion of TIGIT^(+)CD8^(+)T cells expressing CD137 and CD69 simultaneously was observed in HCs than in PLWH based on the activation-induced marker assay.Compared with 0W,SARS-CoV-2-specific TIGIT^(+)CD8^(+)T-cell responses in PLWH were not enhanced at 12W but were enhanced in HCs.Additionally,at all time points,the SARS-CoV-2-specific responses of TIGIT^(+)CD8^(+)T cells in PLWH were significantly weaker than those of TIGIT-CD8^(+)T cells.However,in HCs,the difference in the SARS-CoV-2-specific responses induced between TIGIT^(+)CD8^(+)T cells and TIGIT-CD8^(+)T cells was insignificant at 4W and 12W,except at 0W.Conclusions:TIGIT expression on CD8^(+)T cells may hinder the T-cell immune response to a booster dose of an inactivated SARS-CoV-2 vaccine,suggesting weakened resistance to SARS-CoV-2 infection,especially in PLWH.Furthermore,TIGIT may be used as a potential target to increase the production of SARS-CoV-2-specific CD8^(+)T cells,thereby enhancing the effectiveness of vaccination.

Molecular network-based intervention brings us closer to ending the HIV pandemic

Precise identification of HIV transmission among populations is a key step in public health responses.However,the HIV transmission network is usually difficult to determine.HIV molecular networks can be determined by phylogenetic approach,genetic distance-based approach,and a combination of both approaches.These approaches are increasingly used to identify transmission networks among populations,reconstruct the history of HIV spread,monitor the dynamics of HIV transmission,guide targeted intervention on key subpopulations,and assess the effects of interventions.Simulation and retrospective studies have demonstrated that these molecular network-based interventions are more cost-effective than random or traditional interventions.However,we still need to address several challenges to improve the practice of molecular network-guided targeting interventions to finally end the HIV epidemic.The data remain limited or difficult to obtain,and more automatic real-time tools are required.In addition,molecular and social networks must be combined,and technical parameters and ethnic issues warrant further studies.

Immunological and virological characteristics of human immunodeficiency virus type i superinfection： implications in vaccine design

Superinfection is frequently detected among individuals infected by human immunodeficiency virus type I （HIV-1）. Superinfection occurs at similar frequencies at acute and chronic infection stages but less frequently than primary infection. This observation indicates that the immune responses elicited by natural HIV-1 infection may play a role in curb of superinfection; however, these responses are not sufficiently strong to completely prevent superinfection. Thus, a successful HIV-1 vaccine likely needs to induce more potent and broader immune responses than those elicited by primary infection. On the other hand, potent and broad neutralization responses are more often detected after superinfection than during monoinfection. This suggests that broadly neutralizing antibodies are more likely induced by sequential immunization of multiple different immunogens than with only one form of envelope glycoprotein immunogens. Understanding why the protection from superinfection by immunity induced by primary infection is insufficient and if superinfection can lead to cross-reactive immune responses will be highly informative for HIV-1 vaccine design.

Cognitive Computing-Based CDSS in Medical Practice

Importance.The last decade has witnessed the advances of cognitive computing technologies that learn at scale and reason with purpose in medicine studies.From the diagnosis of diseases till the generation of treatment plans,cognitive computing encompasses both data-driven and knowledge-driven machine intelligence to assist health care roles in clinical decision-making.This review provides a comprehensive perspective from both research and industrial efforts on cognitive computing-based CDSS over the last decade.Highlights.(1)A holistic review of both research papers and industrial practice about cognitive computing-based CDSS is conducted to identify the necessity and the characteristics as well as the general framework of constructing the system.(2)Several of the typical applications of cognitive computing-based CDSS as well as the existing systems in real medical practice are introduced in detail under the general framework.(3)The limitations of the current cognitive computing-based CDSS is discussed that sheds light on the future work in this direction.Conclusion.Different from medical content providers,cognitive computing-based CDSS provides probabilistic clinical decision support by automatically learning and inferencing from medical big data.The characteristics of managing multimodal data and computerizing medical knowledge distinguish cognitive computing-based CDSS from other categories.Given the current status of primary health care like high diagnostic error rate and shortage of medical resources,it is time to introduce cognitive computing-based CDSS to the medical community which is supposed to be more open-minded and embrace the convenience and low cost but high efficiency brought by cognitive computing-based CDSS.

The Establishment and Spatiotemporal History of A Novel HIV-1 CRF01_AE Lineage in Shenyang City, Northeastern China in 2002–2019

Dear Editor,In China,HIV-1 CRF01_AE has always been one of the most prevalent subtypes,especially among sexually active population,since it was initially reported in Yunnan and Guangxi Provinces during the early 1990s(Cheng et al.1994;Yu et al.1998;Chen et al.1999).Multiple independent introductions of CRF01_AE have led to the establishment of at least eight epidemic lineages in China,which have been circulating among different high-risk populations and have variable prevalence and geographic distribution(Li et al.2017).

Practice and Prospect:HIV-1 Molecular NetworkBased Studies in China

Identification of human immunodeficiency virus(HIV)transmission networks is a critical step in the public health response;however,it is challenging to achieve this through traditional epidemiological surveys alone.The molecular network approach can provide more accurate information for understanding HIV outbreaks and bring targeted interventions into reality.Based on the current global development of the concept of the molecular network,Chinese scientists have in recent years explored the applications of molecular networks for understanding the HIV-1 transmission trends,for identifying the population acquiring priority interventions,and for evaluating the targeted intervention effectiveness.In this review,we focus on research progress by Chinese scientists in the field of molecular networks and put forward some suggestions for future research of molecular networks.

Advances in technology for the laboratory diagnosis of individuals with HIV/AIDS coinfected with Mycobacterium tuberculosis

The high morbidity and mortality rate of individuals with human immunodeficiency virus(HIV)/acquired immunodeficiency syndrome(AIDS)coinfected with Mycobacterium tuberculosis(MTB)is a tough challenge for current global tuberculosis prevention and control efforts.HIV/MTB coinfection is more complex than a single infection,and the interaction between the two diseases aggravates the deterioration caused by the disease,resulting in increased hospitalizations and deaths.Rapid screening and early diagnosis facilitate the timely initiation of anti-tuberculosis treatment in HIV/MTB coinfected individuals,thereby reducing transmission and the incidence of adverse prognoses.To date,pathogenic detection has remained the gold standard for diagnosing tuberculosis,but its sensitivity and specificity are greatly affected by the body's immune status,which limits its application in the diagnosis of HIV/MTB coinfection.Recently,immunology and molecular detection technology has developed rapidly.New detection technologies,such as interferon-γ release assays,interferon-gamma inducible protein 10,and GeneXpert MTB/RIF assay have overcome the limitations of traditional detection methods,significantly improved the sensitivity and specificity of tuberculosis diagnosis,and brought new hope to the detection of HIV/MTB coinfection.In this article,the principle,scope of application,and latest research progress of relevant detection methods are reviewed to provide a reference for the early diagnosis of HIV/MTB coinfection.