Displaying publications 1 - 20 of 37 in total

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  1. Phage N15-Based Vectors for Gene Cloning and Expression in Bacteria and Mammalian Cells
    Wong YC, Ng AWR, Chen Q, Liew PS, Lee CW, Sim EUH, et al.
    ACS Synth Biol, 2023 Apr 21;12(4):909-921.
    PMID: 37026178 DOI: 10.1021/acssynbio.2c00580
    Bacteriophage N15 is the first virus known to deliver linear prophage into Escherichia coli. During its lysogenic cycle, N15 protelomerase (TelN) resolves its telomerase occupancy site (tos) into hairpin telomeres. This protects the N15 prophage from bacterial exonuclease degradation, enabling it to stably replicate as a linear plasmid in E. coli. Interestingly, purely proteinaceous TelN can retain phage DNA linearization and hairpin formation without involving host- or phage-derived intermediates or cofactors in the heterologous environment. This unique feature has led to the advent of synthetic linear DNA vector systems derived from the TelN-tos module for the genetic engineering of bacterial and mammalian cells. This review will focus on the development and advantages of N15-based novel cloning and expression vectors in the bacterial and mammalian environments. To date, N15 is the most widely exploited molecular tool for the development of linear vector systems, especially the production of therapeutically useful miniDNA vectors without a bacterial backbone. Compared to typical circular plasmids, linear N15-based plasmids display remarkable cloning fidelity in propagating unstable repetitive DNA sequences and large genomic fragments. Additionally, TelN-linearized vectors with the relevant origin of replication can replicate extrachromosomally and retain transgenes functionality in bacterial and mammalian cells without compromising host cell viability. Currently, this DNA linearization system has shown robust results in the development of gene delivery vehicles, DNA vaccines and engineering mammalian cells against infectious diseases or cancers, highlighting its multifaceted importance in genetic studies and gene medicine.
  2. Crude protein extraction protocol for phage N15 protelomerase in vitro enzymatic assays
    Chen Q, Narayanan K
    Anal Biochem, 2011 Jul 1;414(1):169-71.
    PMID: 21396906 DOI: 10.1016/j.ab.2011.03.006
    The phage N15 protelomerase enzyme (TelN) is essential for the replication of its genome by resolution of its telRL domain, located within a telomerase occupancy site (tos), into hairpin telomeres. Isolation of TelN for in vitro processing of tos, however, is a highly complex process, requiring multiple purification steps. In this study a simplified protocol for crude total protein extraction is described that retains the tos-cleaving activity of TelN for at least 4 weeks, greatly simplifying in vitro testing of its activity. This protocol may be extended for functional analysis of other phage and bacterial proteins, particularly DNA-processing enzymes.
  3. Phage N15 protelomerase resolves its tos recognition site into hairpin telomeres within mammalian cells
    Liew PS, Chen Q, Ng AWR, Chew YC, Ravin NV, Sim EUH, et al.
    Anal Biochem, 2019 10 15;583:113361.
    PMID: 31306622 DOI: 10.1016/j.ab.2019.113361
    Phage N15 protelomerase (TelN) cleaves double-stranded circular DNA containing a telomerase-occupancy-site (tos) and rejoins the resulting linear-ends to form closed-hairpin-telomeres in Escherichia coli (E. coli). Continued TelN expression is essential to support resolution of the linear structure. In mammalian cells, no enzyme with TelN-like activities has been found. In this work, we show that phage TelN, expressed transiently and stably in human and mouse cells, recapitulates its native activities in these exogenous environments. We found TelN to accurately resolve tos-DNA in vitro and in vivo within human and mouse cells into linear DNA-containing terminal telomeres that are resistant to RecBCD degradation, a hallmark of protelomerase processing. In stable cells, TelN activity was detectable for at least 60 days, which suggests the possibility of limited silencing of its expression. Correspondingly, linear plasmid containing a 100 kb human β-globin gene expressed for at least 120 h in non-β-globin-expressing mouse cells with TelN presence. Our results demonstrate TelN is able to cut and heal DNA as hairpin-telomeres within mammalian cells, providing a tool for creating novel structures by DNA resolution in these hosts. The TelN protelomerase may be useful for exploring novel technologies for genome interrogation and chromosome engineering.
  4. Fulltext Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)
    Klionsky DJ, Abdelmohsen K, Abe A, Abedin MJ, Abeliovich H, Acevedo Arozena A, et al.
    Autophagy, 2016;12(1):1-222.
    PMID: 26799652 DOI: 10.1080/15548627.2015.1100356
  5. Fulltext Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1
    Klionsky DJ, Abdel-Aziz AK, Abdelfatah S, Abdellatif M, Abdoli A, Abel S, et al.
    Autophagy, 2021 Jan;17(1):1-382.
    PMID: 33634751 DOI: 10.1080/15548627.2020.1797280
    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.
  6. Research advances in citrus polyphenols: green extraction technologies, gut homeostasis regulation, and nano-targeted delivery system application
    Liu Y, Yan N, Chen Q, Dong L, Li Y, Weng P, et al.
    Crit Rev Food Sci Nutr, 2023 Aug 08.
    PMID: 37552798 DOI: 10.1080/10408398.2023.2239350
    Citrus polyphenols can modulate gut microbiota and such bi-directional interaction that can yield metabolites such as short-chain fatty acids (SCFAs) to aid in gut homeostasis. Such interaction provides citrus polyphenols with powerful prebiotic potential, contributing to guts' health status and metabolic regulation. Citrus polyphenols encompass unique polymethoxy flavonoids imparting non-polar nature that improve their bioactivities and ability to penetrate the blood-brain barrier. Green extraction technology targeting recovery of these polyphenols has received increasing attention due to its advantages of high extraction yield, short extraction time, low solvent consumption, and environmental friendliness. However, the low bioavailability of citrus polyphenols limits their applications in extraction from citrus by-products. Meanwhile, nano-encapsulation technology may serve as a promising approach to improve citrus polyphenols' bioavailability. As citrus polyphenols encompass multiple hydroxyl groups, they are potential to interact with bio-macromolecules such as proteins and polysaccharides in nano-encapsulated systems that can improve their bioavailability. This multifaceted review provides a research basis for the green and efficient extraction techniques of citrus polyphenols, as well as integrated mechanisms for its anti-inflammation, alleviating metabolic syndrome, and regulating gut homeostasis, which is more capitalized upon using nano-delivery systems as discussed in that review to maximize their health and food applications.
  7. Research advance of non-thermal processing technologies on ovalbumin properties: The gelation, foaming, emulsification, allergenicity, immunoregulation and its delivery system application
    Chen Q, Dong L, Li Y, Liu Y, Xia Q, Sang S, et al.
    Crit Rev Food Sci Nutr, 2023 Feb 20.
    PMID: 36803106 DOI: 10.1080/10408398.2023.2179969
    Ovalbumin (OVA) is the most abundant protein in egg white, with excellent functional properties (e.g., gelling, foaming, emulsifying properties). Nevertheless, OVA has strong allergenicity, which is usually mediated by specific IgE thus results in gut microbiota dysbiosis and causes atopic dermatitis, asthma, and other inflammation actions. Processing technologies and the interactions with other active ingredients can influence the functional properties and allergic epitopes of OVA. This review focuses on the non-thermal processing technologies effects on the functional properties and allergenicity of OVA. Moreover, the research advance about immunomodulatory mechanisms of OVA-mediated food allergy and the role of gut microbiota in OVA allergy was summarized. Finally, the interactions between OVA and active ingredients (such as polyphenols and polysaccharides) and OVA-based delivery systems construction are summarized. Compared with traditional thermal processing technologies, novel non-thermal processing techniques have less damage to OVA nutritional value, which also improve OVA properties. OVA can interact with various active ingredients by covalent and non-covalent interactions during processing, which can alter the structure or allergic epitopes to affect OVA/active components properties. The interactions can promote OVA-based delivery systems construction, such as emulsions, hydrogels, microencapsulation, nanoparticles to encapsulate bioactive components and monitor freshness for improving foods quality and safety.
  8. Current Updates on Bone Grafting Biomaterials and Recombinant Human Growth Factors Implanted Biotherapy for Spinal Fusion: A Review of Human Clinical Studies
    Li G, Li P, Chen Q, Thu HE, Hussain Z
    Curr Drug Deliv, 2019;16(2):94-110.
    PMID: 30360738 DOI: 10.2174/1567201815666181024142354
    BACKGROUND: Owing to their great promise in the spinal surgeries, bone graft substitutes have been widely investigated for their safety and clinical potential. By the current advances in the spinal surgery, an understanding of the precise biological mechanism of each bone graft substitute is mandatory for upholding the induction of solid spinal fusion.

    OBJECTIVE: The aim of the present review is to critically discuss various surgical implications and level of evidence of most commonly employed bone graft substitutes for spinal fusion.

    METHOD: Data was collected via electronic search using "PubMed", "SciFinder", "ScienceDirect", "Google Scholar", "Web of Science" and a library search for articles published in peer-reviewed journals, conferences, and e-books.

    RESULTS: Despite having exceptional inherent osteogenic, osteoinductive, and osteoconductive features, clinical acceptability of autografts (patient's own bone) is limited due to several perioperative and postoperative complications i.e., donor-site morbidities and limited graft supply. Alternatively, allografts (bone harvested from cadaver) have shown great promise in achieving acceptable bone fusion rate while alleviating the donor-site morbidities associated with implantation of autografts. As an adjuvant to allograft, demineralized bone matrix (DBM) has shown remarkable efficacy of bone fusion, when employed as graft extender or graft enhancer. Recent advances in recombinant technologies have made it possible to implant growth and differentiation factors (bone morphogenetic proteins) for spinal fusion.

    CONCLUSION: Selection of a particular bone grafting biotherapy can be rationalized based on the level of spine fusion, clinical experience and preference of orthopaedic surgeon, and prevalence of donor-site morbidities.

  9. Historical atmospheric pollution trends in Southeast Asia inferred from lake sediment records
    Engels S, Fong LSRZ, Chen Q, Leng MJ, McGowan S, Idris M, et al.
    Environ Pollut, 2018 Apr;235:907-917.
    PMID: 29353806 DOI: 10.1016/j.envpol.2018.01.007
    Fossil fuel combustion leads to increased levels of air pollution, which negatively affects human health as well as the environment. Documented data for Southeast Asia (SEA) show a strong increase in fossil fuel consumption since 1980, but information on coal and oil combustion before 1980 is not widely available. Spheroidal carbonaceous particles (SCPs) and heavy metals, such as mercury (Hg), are emitted as by-products of fossil fuel combustion and may accumulate in sediments following atmospheric fallout. Here we use sediment SCP and Hg records from several freshwater lentic ecosystems in SEA (Malaysia, Philippines, Singapore) to reconstruct long-term, region-wide variations in levels of these two key atmospheric pollution indicators. The age-depth models of Philippine sediment cores do not reach back far enough to date first SCP presence, but single SCP occurrences are first observed between 1925 and 1950 for a Malaysian site. Increasing SCP flux is observed at our sites from 1960 onward, although individual sites show minor differences in trends. SCP fluxes show a general decline after 2000 at each of our study sites. While the records show broadly similar temporal trends across SEA, absolute SCP fluxes differ between sites, with a record from Malaysia showing SCP fluxes that are two orders of magnitude lower than records from the Philippines. Similar trends in records from China and Japan represent the emergence of atmospheric pollution as a broadly-based inter-region environmental problem during the 20th century. Hg fluxes were relatively stable from the second half of the 20th century onward. As catchment soils are also contaminated with atmospheric Hg, future soil erosion can be expected to lead to enhanced Hg flux into surface waters.
  10. Fulltext Future trends and guidance for the triple bottom line and sustainability: a data driven bibliometric analysis
    Tseng ML, Chang CH, Lin CR, Wu KJ, Chen Q, Xia L, et al.
    Environ Sci Pollut Res Int, 2020 Sep;27(27):33543-33567.
    PMID: 32572746 DOI: 10.1007/s11356-020-09284-0
    This study conducts a comprehensive literature review of articles on the triple bottom line (TBL) published from January 1997 to September 2018 to provide significant insights and support to guide further discussion. There were three booms in TBL publications, occurring in 2003, 2011, and 2015, and many articles attempt to address the issue of sustainability by employing the TBL. This literature analysis includes 720, 132, and 58 articles from the Web of Science (WOS), Inspec, and Scopus databases, respectively, and reveals the gaps in existing research. To discover the barriers and points of overlap, these articles are categorized into six aspects of the TBL: economic, environmental, social, operations, technology, and engineering. Examining the top 3 journals in terms of published articles on each aspect reveals the research trends and gaps. The findings provide solid evidence confirming the argument that the TBL as currently defined is insufficient to cover the entire concept of sustainability. The social and engineering aspects still require more discussion to support the linkage of the TBL and to reinforce its theoretical basis. Additionally, to discover the gaps in the data sources, theories applied, methods adopted, and types of contributions, this article summarizes 82 highly cited articles covering each aspect. This article offers theoretical insights by identifying the top contributing countries, institutions, authors, keyword networks, and authorship networks to encourage scholars to push the current discussion further forward, and it provides practical insights to bridge the gap between theory and practice for enhancing the efficiency and effectiveness of improvements.
  11. Associations between environmental characteristics, high-resolution indoor microbiome, metabolome and allergic and non-allergic rhinitis symptoms for junior high school students
    Fu X, Du B, Meng Y, Li Y, Zhu X, Ou Z, et al.
    Environ Sci Process Impacts, 2023 Mar 08.
    PMID: 36883483 DOI: 10.1039/d2em00480a
    Rhinitis is one of the most prevalent chronic diseases globally. Microbiome exposure affects the occurrence of rhinitis. However, previous studies did not differentiate allergic rhinitis (AR) and non-allergic rhinitis (NAR) in the microbial association analysis. In this study, we investigate 347 students in 8 junior high schools, Terengganu, Malaysia, who were categorized as healthy (70.9%), AR (13.8%) and NAR (15.3%) based on a self-administered questionnaire and skin prick tests of pollen, pet, mould and house dust mite allergens. Classroom microbial and metabolite exposure in vacuumed dust was characterized by PacBio long-read amplicon sequencing, quantitative PCR and LC-MS-based untargeted metabolomics. Our findings indicate a similar microbial association pattern between AR and NAR. The richness in Gammaproteobacteria was negatively associated with AR and NAR symptoms, whereas total fungal richness was positively associated with AR and NAR symptoms (p < 0.05). Brasilonema bromeliae and Aeromonas enteropelogenes were negatively associated with AR and NAR, and Deinococcus was positively associated with AR and NAR (p < 0.01). Pipecolic acid was protectively associated with AR and NAR symptoms (OR = 0.06 and 0.13, p = 0.009 and 0.045). A neural network analysis showed that B. bromeliae was co-occurring with pipecolic acid, suggesting that the protective role of this species may be mediated by releasing pipecolic acid. Indoor relative humidity and the weight of vacuum dust were associated with AR and NAR, respectively (p < 0.05), but the health effects were mediated by two protective bacterial species, Aliinostoc morphoplasticum and Ilumatobacter fluminis. Overall, our study reported a similar microbial association pattern between AR and NAR and also revealed the complex interactions between microbial species, environmental characteristics, and rhinitis symptoms.
  12. Differences in late cardiovascular mortality following acute myocardial infarction in three major Asian ethnic groups
    de Carvalho LP, Gao F, Chen Q, Hartman M, Sim LL, Koh TH, et al.
    Eur Heart J Acute Cardiovasc Care, 2014 Dec;3(4):354-62.
    PMID: 24598820 DOI: 10.1177/2048872614527007
    the purpose of this study was to investigate differences in long-term mortality following acute myocardial infarction (AMI) in patients from three major ethnicities of Asia.
  13. The binding mechanism of oat phenolic acid to whey protein and its inhibition mechanism against AGEs as revealed using spectroscopy, chromatography and molecular docking
    Dong L, Zhang Y, Li Y, Liu Y, Chen Q, Liu L, et al.
    Food Funct, 2023 Nov 13;14(22):10221-10231.
    PMID: 37916290 DOI: 10.1039/d3fo02474a
    Heat sterilization of dairy products can promote the formation of advanced glycation end products (AGEs), protein oxidation products (POPs) and α-dicarbonyl compounds, which have a significant influence on health due to the close association of these products with diabetes complications. In this study, eight oat phenolic acids were first analyzed for their inhibitory effect against AGEs formation. Due to their strong inhibitory effects and structural differences, caffeic acid (CA) and gallic acid (GA) were further selected to assess their anti-glycosylation mechanisms using spectroscopy, chromatography and molecular docking. CA/GA reduced the production of total AGEs and POPs in various bovine milk simulation models and protected whey proteins from structural modifications, oxidation, and cross-linking. Comparative analyses showed a structure-effect relationship between CA/GA and AGEs inhibition. Oat phenolic acids against AGEs and POPs might be related to the unique bonding of key amino acid residues in whey proteins, the inhibitory role of early fructosamine and the trapping of reactive α-dicarbonyl groups to form adducts. In conclusion, oat phenolic acids might present a promising dietary strategy to alleviate AGEs production and glycation of proteins in dairy products upon storage.
  14. Research advances of advanced glycation end products in milk and dairy products: Formation, determination, control strategy and immunometabolism via gut microbiota
    Dong L, Li Y, Chen Q, Liu Y, Qiao Z, Sang S, et al.
    Food Chem, 2023 Aug 15;417:135861.
    PMID: 36906946 DOI: 10.1016/j.foodchem.2023.135861
    Advanced glycosylation end products (AGEs) are a series of complex compounds which generate in the advanced phase of Maillard reaction, which can pose a non-negligible risk to human health. This article systematically encompasses AGEs in milk and dairy products under different processing conditions, influencing factors, inhibition mechanism and levels among the different categories of dairy products. In particular, it describes the effects of various sterilization techniques on the Maillard reaction. Different processing techniques have a significant effect on AGEs content. In addition, it clearly articulates the determination methods of AGEs and even discusses its immunometabolism via gut microbiota. It is observed that the metabolism of AGEs can affect the composition of the gut microbiota, which further has an impact on intestinal function and the gut-brain axis. This research also provides a suggestion for AGEs mitigation strategies, which are beneficial to optimize the dairy production, especially innovative processing technology application.
  15. Ultrasound and enzyme assisted preparation of novel lactoferrin-cereal phenolic acid conjugates: structural, physicochemical and functional properties
    Li Y, Dong L, Liu Y, Chen Q, Wu Z, Liu L, et al.
    Food Chem, 2024 Mar 01;435:137572.
    PMID: 37778268 DOI: 10.1016/j.foodchem.2023.137572
    The effects of covalent binding of protocatechuic acid (PA) and gallic acid (GA) to lactoferrin (LF) on the structure, functional, and antioxidant properties of the protein conjugate were investigated. These protein-phenolic conjugates were produced by laccase cross-linking and ultrasound-assisted free radical grafting, which were characterized using turbidity, particle size, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses. Structural changes in conjugates were monitored by endogenous fluorescence spectroscopy, fourier transform infrared spectroscopy (FTIR), and circular dichroism (CD). The antioxidant capacities and pH stability were determined using DPPH, ABTS, FRAP, and potentiometric analysis. The enzymatic cross-linking and free radical grafting yielded LF-PA/GA conjugates with altered hydrodynamic diameter and zeta-potential. Spectroscopic and chromatographic analyses revealed that binding to PA/GA altered the molecular structure of LF, with a decrease in LF isoelectric point post binding to PA/GA, without affecting antioxidant activities. In conclusion, LF-PA/GA conjugates present potential applications in the food industry.
  16. Characterization and determination of casein glycomacropeptide in dairy products by UHPLC-MS/MS based on its characteristic peptide
    Chen Q, Lai S, Dong L, Liu Y, Pan D, Wu Z, et al.
    Food Chem, 2024 Jan 01;430:137049.
    PMID: 37544157 DOI: 10.1016/j.foodchem.2023.137049
    The ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS) method was built to quantify the casein glycomacropeptide (CGMP) in bovine dairy products accurately based on targeted proteomics. Qualitative analysis of theoretical peptides was carried out using high-resolution mass spectrometry (HRMS) and protein software. Isotope-labeled characteristic peptides were acquired via the labeled amino acid condensation method to correct the matrix effects. Peptide MAIPPK was the representative characteristic peptide for distinguishing the CGMP from κ-casein through trypsin digestion. After optimizing the pre-treatment conditions, the final 8% oxidant concentration was selected and the 10% formic acid concentration with 2.5 h oxidation time. Moreover, the results of methodological verification showed that the recovery rate was 103.7%, meanwhile the precision of inter-day and intra-day was less than 5%. In conclusion, the research demonstrated the characteristic peptide MAIPPK could quantitatively applied to detect CGMP in dairy products.
  17. Fulltext Inhibition Effect of Extract of Psychotria viridiflora Stem on α-Amylase and α-Glucosidase and Its Application in Lowering the Digestibility of Noodles
    Chen Q, Toy JYH, Seta C, Yeo TC, Huang D
    Front Nutr, 2021;8:701114.
    PMID: 34458304 DOI: 10.3389/fnut.2021.701114
    A collection of tropical medicinal plants from East Malaysia's rainforests are used by indigenous tribes for their curative properties. Despite their purported healing properties, these forest plant species are largely unexplored and hence remain virtually unknown to the outside world. In this study, antidiabetic properties of Psychotria viridiflora, a plant used to treat diabetes by a local community in Sarawak, Malaysia were investigated. Ethyl acetate (EA) extract of P. viridiflora stem was found to exhibit high starch hydrolase inhibition activity with an IC50 value of 15.4 ± 2.1 μg/ml against porcine α-amylase and an IC50 value of 32.4 ± 3.7 μg/ml against rat intestinal α-glucosidase. A complex mixture of A-type oligomeric proanthocyanidins containing (epi)fisetinidol, (epi)afzelechin, (epi)guibourtinidol, and (epi)catechin were found. These compounds may be responsible for the starch hydrolase inhibition activity. Ethyl acetate (EA) extract of P. viridiflora stem was incorporated into wheat and rice flour to reformulate noodles with slow digestibility and was assessed under in vitro simulated gastrointestinal conditions. A dose-dependent effect on digestibility was observed for both noodles upon incorporation of 1-6% (w/w) of EA extract, with noodles containing 6% (w/w) extract exhibiting the greatest reduction in digestibility. As compared to rice noodles containing 6% extract (31.16% inhibition), wheat noodles with the same extract concentration had a smaller decline in digestibility (27.25% inhibition) after 180 min. Overall, our findings highlight the potential of P. viridiflora in the prevention of postprandial hyperglycaemia.
  18. Fulltext The Relationship Between K-Workers' Leader-Member Exchange, Organizational Citizenship Behavior and Task Performance-Evidence From Chinese Hospitals
    Che X, Guo Z, Chen Q
    Front Psychol, 2021;12:625584.
    PMID: 34305701 DOI: 10.3389/fpsyg.2021.625584
    Aiming to reduce the difficulty of managing and motivating knowledge workers (k-workers), and promote the psychological well-being of them in Chinese hospitals, this study examines how k-workers' leader-member exchange (LMX) influences their task performance and the mediation effect of organizational citizenship behavior (OCB). Through a self-administered survey, valid questionnaires were collected from 384 k-workers in Chinese hospitals, and partial least squares structural equation modeling was employed for data analysis. The findings show that LMX is positively related to OCB and task performance, and that OCB mediates the relationship between LMX and task performance. This research has theoretical implications and also provides practical suggestions on how to manage, motivate, and inspire k-workers, and promote the psychological well-being of them, and finally enhance the organizational performance in Chinese hospitals.
  19. The role of linguistic and cognitive skills in reading Chinese as a second language: A path analysis modeling approach
    Yang L, Xiong Y, Chen Q
    Front Psychol, 2023;14:1131913.
    PMID: 37082568 DOI: 10.3389/fpsyg.2023.1131913
    This study examined the role of basic linguistic skills (vocabulary, syntax, orthography, and morphological awareness), basic cognitive skills (working memory), and higher-order cognitive skills (inference making and reading monitoring) in reading Chinese as a second language (L2). A total of 252 international students from Pakistan, Indonesia, Malaysia, and Laos were recruited, and a range of measures including a Chinese reading comprehension test (HSK level 3), four linguistic knowledge tests on Chinese lexical, syntactic, and orthographic knowledge as well as morphological awareness, a reading span test, an inference making task, and an inconsistency detection test. The results of hierarchical multiple regressions showed that the measured linguistic skills and cognitive skills explained 80% of the variances in L2 Chinese reading, among which morphological awareness made the largest contribution. The path analysis revealed that linguistic skills and working memory contributed indirectly to reading comprehension via inference making and comprehension monitoring, while the two higher-order cognitive skills made direct contributions. Overall, this study demonstrates that inference making and comprehension monitoring contributed directly to reading comprehension, while linguistic skills and working memory functioned indirectly via the higher-order cognitive skills It also highlights the importance of morphological awareness in a hierarchical model of L2 Chinese reading.
  20. Induction of protein expression within Escherichia coli vector for entry into mammalian cells
    Chen Q, Lee CW, Sim EU, Narayanan K
    Hum Gene Ther Methods, 2014 Feb;25(1):40-7.
    PMID: 24134118 DOI: 10.1089/hgtb.2012.188
    Direct protein delivery into the cytosol of mammalian cells by invasive Escherichia coli (E. coli) bacterial vector will bypass the need to achieve nuclear entry and transcription of DNA, a major hurdle that is known to seriously limit gene transfer. The bacterial vector is induced to express the protein during its growth phase, before presentation for entry into mammalian cells and release of its content into the cellular environment. For this class of vector, crossing the plasma membrane becomes the primary step that determines the success of protein delivery. Yet, how the mechanics of protein expression within the vector affect its entry into the host is poorly understood. We found the vector's effectiveness to enter HeLa cells diminished together with its viability when phage N15 protelomerase (TelN) expression was induced continuously in the invasive E. coli despite producing an abundant amount of functional protein. By comparison, shorter induction, even as little as 3 hr, produced sufficient amounts of functional TelN and showed more effective invasion of HeLa cells, comparable to that of uninduced invasive E. coli. These results demonstrate that brief induction of protein expression during vector growth is essential for optimal entry into mammalian cells, an important step for achieving bacteria-mediated protein delivery.
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