Antimicrobial activity of a conjugated polymer with cationic backbone

Xu, Qingling,He, Ping,Wang, Jianwu,Chen, Hui,Lv, Fengting,Liu, Libing,Wang, Shu,Yoon, Juyoung Elsevier 2019 Dyes and pigments Vol.160 No.-

<P><B>Abstract</B></P> <P>Owing to the misuse of antibiotics and slow development of new drugs, antibiotic-resistant pathogens have become a serious threat to human health. With the aim of developing new antimicrobial agents, we designed and synthesized a new conjugated polymer (<B>PFPhim</B>), which possesses an imidazolium containing backbone. The cationic backbone enables it to strongly interact with bacterial membrane leading to an antimicrobial ability that is more potent than that of a conjugated polymer containing a neutral backbone. <B>PFPhim</B> also displays strong photodynamic antimicrobial activity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A conjugated polymer possessing imidazolium in the backbone was synthesized. </LI> <LI> The polymer shows good an bacterial ability over Ampr E. Coli in darkness. </LI> <LI> The polymer also displays strong photodynamic antimicrobial activity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Development of a Selective Fluorescent Probe for Hypochlorous Acid Detection and Imaging

Qingling Xu,최민정,김경미,이상협,윤주영 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.12

Visual detection of dopamine and monitoring tyrosinase activity using a pyrocatechol violet–Sn⁴⁺ complex

Xu, Qingling,Yoon, Juyoung Royal Society of Chemistry 2011 Chemical communications Vol.47 No.46

<P>In this study, the ensemble of pyrocatechol violet and Sn<SUP>4+</SUP> was used for dopamine detection in a neutral aqueous solution with high selectivity and sensitivity. The detection course showed three color changes, which could be observed by the naked eye. We also demonstrated that this ensemble can be used to monitor tyrosinase activity.</P> <P>Graphic Abstract</P><P>A new method for optical and spectroscopic dopamine detection and tyrosinase activity monitoring has been developed using a pyrocatechol violet–Sn<SUP>4+</SUP> complex. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1cc15587c'> </P>

Polydiacetylene-Based Colorimetric and Fluorescent Chemosensor for the Detection of Carbon Dioxide

Xu, Qingling,Lee, Songyi,Cho, Yukyung,Kim, Myung Hwa,Bouffard, Jean,Yoon, Juyoung American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.47

<P>We developed a colorimetric and fluorescent turn-on carbon dioxide sensor that relies on a polydiacetylene, <B>PDA-1</B>, functionalized with amines and imidazolium groups. The pendant amines react with CO<SUB>2</SUB> under basic conditions to form carbamoate anions, which partially neutralize the polymer’s positive charges, inducing a phase transition. <B>PDA-1</B> allows for the selective sensing of CO<SUB>2</SUB> with high sensitivity, down to atmospheric concentrations. Naked-eye detection of CO<SUB>2</SUB> is accomplished either in water solutions of <B>PDA-1</B> or in the solid state with electrospun coatings of <B>PDA-1</B> nanofibers.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-47/ja410557x/production/images/medium/ja-2013-10557x_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja410557x'>ACS Electronic Supporting Info</A></P>

Visual detection of copper ions based on azide- and alkyne-functionalized polydiacetylene vesicles

Xu, Qingling,Lee, Kyung Mi,Wang, Fang,Yoon, Juyoung Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.39

<P>A new method for visual detection of Cu<SUP>2+</SUP> based on azide- and alkyne-functionalized polydiacetylene (PDA-aa) vesicles has been developed. In the presence of ascorbic acid, Cu<SUP>2+</SUP> can be reduced to Cu<SUP>+</SUP> and catalyze the click reaction between the two functional groups. After incubation with Cu<SUP>2+</SUP> and ascorbic acid, a PDA-aa solution changed its color from blue to red, which was attributed to conformational transition of the conjugated backbone. Other metal ions were explored but only induced negligible color changes. This method provides a naked eye detection of Cu<SUP>2+</SUP> in water without the aid of complex instruments.</P> <P>Graphic Abstract</P><P>A new Cu<SUP>2+</SUP> sensor based on polydiacetylene vesicles with imidazolium linked azide and alkyne groups was developed using click chemistry. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm11660f'> </P>

A Highly Specific Fluorescent Probe for Hypochlorous Acid and Its Application in Imaging Microbe-Induced HOCl Production

Xu, Qingling,Lee, Kyung-Ah,Lee, Songyi,Lee, Kyung Mi,Lee, Won-Jae,Yoon, Juyoung American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.26

<P>Oxidative stress induced by reactive oxygen species (ROS) plays crucial roles in a wide range of physiological processes and is also implicated in various diseases, including cancer, chronic inflammatory diseases, and neurodegenerative disorders. Among the various ROS, hypochlorous acid (HOCl) plays as a powerful microbicidal agent in the innate immune system. The regulated production of microbicidal HOCl is required for the host to control the invading microbes. However, as a result of the highly reactive and diffusible nature of HOCl, its uncontrolled production may lead to an adverse effect on host physiology. Because of its biological importance, many efforts have been focused on developing selective fluorescent probes to image ROS. However, it is still challenging to design a fluorescent probe with exclusive selectivity toward a particular member of ROS. In the current work, we designed <B>FBS</B> as a new fluorescent HOCl probe which has high selectivity, sensitivity, and short response time in a broad range of pH. Compared with other sensors, the “dual-lock” structure of <B>FBS</B> has an advantage of eliminating interferences from other ROS/RNS. Importantly, we further showed that our HOCl probe could be applied for the <I>in vivo</I> imaging of physiological HOCl production in the mucosa of live animals. This probe provides a promising tool for the study of HOCl production.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-26/ja404649m/production/images/medium/ja-2013-04649m_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja404649m'>ACS Electronic Supporting Info</A></P>

Chinese Society of Allergy Guidelines for Diagnosis and Treatment of Allergic Rhinitis

Lei Cheng,Jianjun Chen,Qingling Fu,Shaoheng He,Huabin Li,Zheng Liu,Guolin Tan,Zezhang Tao,Dehui Wang,Weiping Wen,Rui Xu,Yu Xu,Qintai Yang,Chonghua Zhang,Gehua Zhang,Ruxin Zhang,Yuan Zhang,Bing Zhou,Do 대한천식알레르기학회 2018 Allergy, Asthma & Immunology Research Vol.10 No.4

Allergic rhinitis (AR) is a global health problem that causes major illnesses and disabilities worldwide. Epidemiologic studies have demonstrated that the prevalence of AR has increased progressively over the last few decades in more developed countries and currently affects up to 40% of the population worldwide. Likewise, a rising trend of AR has also been observed over the last 2-3 decades in developing countries including China, with the prevalence of AR varying widely in these countries. A survey of self-reported AR over a 6-year period in the general Chinese adult population reported that the standardized prevalence of adult AR increased from 11.1% in 2005 to 17.6% in 2011. An increasing number of original articles and imporclinical trials on the epidemiology, pathophysiologic mechanisms, diagnosis, management and comorbidities of AR in Chinese subjects have been published in international peer-reviewed journals over the past 2 decades, and substantially added to our understanding of this disease as a global problem. Although guidelines for the diagnosis and treatment of AR in Chinese subjects have also been published, they have not been translated into English and therefore not generally accessible for reference to non-Chinese speaking international medical communities. Moreover, methods for the diagnosis and treatment of AR in China have not been standardized entirely and some patients are still treated according to regional preferences. Thus, the present guidelines have been developed by the Chinese Society of Allergy to be accessible to both national and international medical communities involved in the management of AR patients. These guidelines have been prepared in line with existing international guidelines to provide evidence-based recommendations for the diagnosis and management of AR in China.

Insertional mutations exhibiting high cell-culture density HCD phenotypes are enriched through continuous subcultures in Chlamydomonas reinhardtii

Leena Thung,Jing He,Qingling Zhu,Zhenyu Xu,Jianhua Liu,Yvonne Chow 한국조류학회I 2018 ALGAE Vol.33 No.1

Low efficiency in microalgal biomass production was largely attributed to the low density of algal cell cultures. Though mutations that reduced the level of chlorophyll or pigment content increased efficiency of photon usage and thus the cell-culture density under high-illumination growth conditions (e.g., >500 µmol photon m-2 s-1), it was unclear whether algae could increase cell-culture density under low-illumination conditions (e.g., ~50 µmol photon m-2 s-1). To address this question, we performed forward genetic screening in Chlamydomonas reinhardtii. A pool of >1,000 insertional mutants was constructed and subjected to continuous subcultures in shaking flasks under low-illumination conditions. Complexity of restriction fragment length polymorphism (RFLP) pattern in cultures indicated the degree of heterogeneity of mutant populations. We showed that the levels of RFLP complexity decreased when cycles of subculture increased, suggesting that cultures were gradually populated by high cell-culture density (HCD) strains. Analysis of the 3 isolated HCD mutants after 30 cycles of subcultures confirmed that their maximal biomass production was 50-100% higher than that of wild type under low-illumination. Furthermore, levels of chlorophyll content in HCD mutant strains were similar to that of wild type. Inverse polymerase chain reaction analysis identified the locus of insertion in two of three HCD strains. Molecular and transcriptomic analyses suggested that two HCD mutants were a result of the gain-of-function phenotype, both linking to the abnormality of mitochondrial functions. Taken together, our results demonstrate that HCD strains can be obtained through continuous subcultures under low illumination conditions.

Ratiometric Two-Photon Fluorescent Probe for Detecting and Imaging Hypochlorite

Pak, Yen Leng,Park, Sang Jun,Xu, Qingling,Kim, Hwan Myung,Yoon, Juyoung American Chemical Society 2018 ANALYTICAL CHEMISTRY - Vol.90 No.15

<P>The ratiometric fluorescent probe <B>B6S</B>, which contains pyrene as a fluorophore and imidazoline-2-thione as a reactive site, was developed for detection of hypochlorite (OCl<SUP>-</SUP>). <B>B6S</B> displays a high specificity toward OCl<SUP>-</SUP> in contrast to other reactive oxygen species and reactive nitrogen species. The probe has a low detection limit and operates under biological conditions. Moreover, the low cytotoxicity of <B>B6S</B> enables it to be utilized effectively for OCl<SUP>-</SUP> imaging in living cells and tissues by using two-photon microscopy. The findings indicate that <B>B6S</B> has the capability of serving as a probe to explore the biological functions of OCl<SUP>-</SUP> in living systems.</P> [FIG OMISSION]</BR>

Insertional mutations exhibiting high cell-culture density HCD phenotypes are enriched through continuous subcultures in Chlamydomonas reinhardtii

Thung, Leena,He, Jing,Zhu, Qingling,Xu, Zhenyu,Liu, Jianhua,Chow, Yvonne The Korean Society of Phycology 2018 ALGAE Vol.33 No.1

Low efficiency in microalgal biomass production was largely attributed to the low density of algal cell cultures. Though mutations that reduced the level of chlorophyll or pigment content increased efficiency of photon usage and thus the cell-culture density under high-illumination growth conditions (e.g., >$500{\mu}mol\;photon\;m^{-2}\;s^{-1}$), it was unclear whether algae could increase cell-culture density under low-illumination conditions (e.g., ${\sim}50{\mu}mol\;photon\;m^{-2}\;s^{-1}$). To address this question, we performed forward genetic screening in Chlamydomonas reinhardtii. A pool of >1,000 insertional mutants was constructed and subjected to continuous subcultures in shaking flasks under low-illumination conditions. Complexity of restriction fragment length polymorphism (RFLP) pattern in cultures indicated the degree of heterogeneity of mutant populations. We showed that the levels of RFLP complexity decreased when cycles of subculture increased, suggesting that cultures were gradually populated by high cell-culture density (HCD) strains. Analysis of the 3 isolated HCD mutants after 30 cycles of subcultures confirmed that their maximal biomass production was 50-100% higher than that of wild type under low-illumination. Furthermore, levels of chlorophyll content in HCD mutant strains were similar to that of wild type. Inverse polymerase chain reaction analysis identified the locus of insertion in two of three HCD strains. Molecular and transcriptomic analyses suggested that two HCD mutants were a result of the gain-of-function phenotype, both linking to the abnormality of mitochondrial functions. Taken together, our results demonstrate that HCD strains can be obtained through continuous subcultures under low illumination conditions.