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1.
Environ Sci Technol ; 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33566596

RESUMO

The frequent detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in healthcare environments, accommodations, and wastewater has attracted great attention to the risk of viral transmission by environmental fomites. However, the process of SARS-CoV-2 adsorption to exposed surfaces in high-risk environments remains unclear. In this study, we investigated the interfacial dynamics of single SARS-CoV-2 pseudoviruses with plasmonic imaging technology. Through the use of this technique, which has high spatial and temporal resolution, we tracked the collision of viruses at a surface and differentiated their stable adsorption and transient adsorption. We determined the effect of the electrostatic force on virus adhesion by correlating the solution and surface chemistry with the interfacial diffusion velocity and equilibrium position. Viral adsorption was found to be enhanced in real scenarios, such as in simulated saliva. This work not only describes a plasmonic imaging method to examine the interfacial dynamics of a single virus but also provides direct measurements of the factors that regulate the interfacial adsorption of SARS-CoV-2 pseudovirus. Such information is valuable for understanding virus transport and environmental transmission and even for designing anticontamination surfaces.

2.
Zootaxa ; 4801(3): zootaxa.4801.3.9, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-33056650

RESUMO

In this work, one new species Microtachycines trispinosus Qin et Li sp. nov. from Sanqingshan of Jiangxi province is described and illustrated with photographs. It is mentioned that Microtachycines fallax Qin, Liu, Li, 2017 should be regarded as the junior synonym of Microtachycines elongatus Qin, Liu Li, 2017. All examined specimens are deposited in Shanghai Entomological Museum, Chinese Academy of Sciences (SEM, CAS).


Assuntos
Ortópteros , Distribuição Animal , Estruturas Animais , Animais , Tamanho Corporal , China , Tamanho do Órgão
3.
Proc Natl Acad Sci U S A ; 117(44): 27148-27153, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33060295

RESUMO

Probing the binding between a microbe and surface is critical for understanding biofilm formation processes, developing biosensors, and designing biomaterials, but it remains a challenge. Here, we demonstrate a method to measure the interfacial forces of bacteria attached to the surface. We tracked the intrinsic fluctuations of individual bacterial cells using an interferometric plasmonic imaging technique. Unlike the existing methods, this approach determined the potential energy profile and quantified the adhesion strength of single cells by analyzing the fluctuations. This method provides insights into biofilm formation and can also serve as a promising platform for investigating biological entity/surface interactions, such as pathogenicity, microbial cell capture and detection, and antimicrobial interface screening.

4.
Zootaxa ; 4809(3): zootaxa.4809.3.5, 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-33055925

RESUMO

A new species of a new genus Melanabropsis. tianmuica gen. sp. nov. is described from China. 3 Japanese species of Anabropsinae are transferred to the new genus. A key to the Chinese genera of subfamily Anabropsinae is given. Materials are deposited in Shanghai Entomological Museum, Chinese Academy of Sciences.


Assuntos
Ortópteros , Distribuição Animal , Estruturas Animais , Animais , Tamanho Corporal , China , Tamanho do Órgão
5.
Anal Chem ; 92(19): 13327-13335, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32794762

RESUMO

The ability to track interfacial dynamics of a single nanoparticle at the solution-solid interface is crucial for understanding physical, chemical, and biological processes, but it remains a challenge. Here, we demonstrated a plasmonic imaging technique that can track unlabeled nanoparticles at the solution-solid interface with high spatial and temporal resolutions. This technique is based on particle-induced interferometric scattering of a surface plasmonic wave, which results in a high vertical sensitivity. Using this ability, we tracked the trajectories of a single nanoparticle interacting with a surface, measured the hydrodynamically hindered diffusion of nanoparticles, and revealed the surface chemistry-dependent behavior of nanoparticles at the interface. The application for tracking formation of membranes from a lipid vesicle was demonstrated, indicating the potential for investigating a broad range of nano-objects at interfaces in a complex environment.

6.
Carbohydr Polym ; 232: 115822, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31952617

RESUMO

Chondroitin sulfate is a linear glycosaminoglycan widely distributed as an important extracellular matrix component of mammalian cells. It participates in numerous pathological processes, however, illustration of its diverse biological roles is hampered by the unavailability of structurally defined chondroitin polymers and their derivatives. Herein, we report a novel homogeneous chondroitin polymers synthetic strategy which combines stepwise oligosaccharides synthesis with one-pot homogeneous chondroitin chain polymerization. Exogenous trisaccharide was proved to be the necessary acceptor for PmCS-catalyzed homogeneous chondroitin polymers synthetic reactions. The strategy exhibited a well-controlled relationship between the final sugar chain length and the molar ratios of reaction substrates that could synthesize homogenous chondroitin polymers with unprecedented narrow molecular weight distribution. More importantly, the strategy was further expanded to synthesis of unnatural zwitterionic and N-sulfonated chondroitin polymers by incorporation of sugar nucleotide derivatives into the synthetic approach.


Assuntos
Condroitina/biossíntese , N-Acetilgalactosaminiltransferases/metabolismo , Polímeros/metabolismo , Configuração de Carboidratos , Condroitina/análogos & derivados , Condroitina/química , Pasteurella multocida/enzimologia , Polimerização , Polímeros/química
7.
Anal Chem ; 92(1): 1309-1315, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31820634

RESUMO

The ability to rapidly and accurately detect water toxicity is crucial for monitoring water quality and assessing toxic risk, but such detection remains a great challenge. Here, we present a plasmonic nanomechanical sensing (PNMS) system for the rapid assessment of water toxicity. This technique is based on the plasmonic sensing of the nanomechanical movement of single bacterial cells, which could be inhibited upon exposure to potential toxicants. By correlating the amplitude of nanomechanical movement with bacterial activity, we detected a variety of toxic substances in water. The direct readout of bacterial activity via PNMS allowed for a high sensitivity to toxicants in water, thereby enabling us to evaluate the acute toxicological effect of chemical compounds rapidly. The PNMS method is promising for online alerts of water quality safety and for assessing chemical hazards. We anticipate that PNMS is also suitable for a wide range of other applications, including bacterial detection and high-throughput screening of antibacterial materials.

8.
Angew Chem Int Ed Engl ; 59(5): 1776-1785, 2020 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-31531917

RESUMO

Surface plasmon resonance microscopy (SPRM) is a versatile platform for chemical and biological sensing and imaging. Great progress in exploring its applications, ranging from single-molecule sensing to single-cell imaging, has been made. In this Minireview, we introduce the principles and instrumentation of SPRM. We also summarize the broad and exciting applications of SPRM to the analysis of single entities. Finally, we discuss the challenges and limitations associated with SPRM and potential solutions.

9.
Angew Chem Int Ed Engl ; 58(13): 4217-4220, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30730602

RESUMO

The development of optical imaging techniques has led to significant advancements in single-nanoparticle tracking and analysis, but these techniques are incapable of label-free selective nanoparticle recognition. A label-free plasmonic imaging technology that is able to identify different kinds of nanoparticles in water is now presented. It quantifies the plasmonic interferometric scattering patterns of nanoparticles and establishes relationships among the refractive index, particle size, and pattern both numerically and experimentally. Using this approach, metallic and metallic oxide particles with different radii were distinguished without any calibration. The ability to optically identify and size different kinds of nanoparticles can provide a promising platform for investigating nanoparticles in complex environments to facilitate nanoscience studies, such as single-nanoparticle catalysis and nanoparticle-based drug delivery.

10.
Zootaxa ; 4402(1): 175-181, 2018 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-29690284

RESUMO

It is difficult to distinguish the genera Svistella and Paratrigonidium on the basis of morphology. Gorochov postulated that Svistella spp. possess the following identification characters: posterior lateral lobes of epiphallus long and narrow at apex, guide rod elongate, attachment plate of the spermatophore consisting of three sclerites (a narrow middle sclerite bearing no protruding structure, and a pair of lateral ones extending to the sides). These features have not been extensively evaluated. In this study, the COI gene was sequenced and was used as a DNA marker to distinguish two genera. The results showed that each genus formed a monophyly, respectively. One new species, Svistella fuscoterminata sp. nov., was found in Yunnan, China. Although its genitalia were similar to that of Paratrigonidium spp., the molecular result supported the new species belonging to Svistella. The specimens are deposited in East China Normal University, Biology of History Museum (ECNU) and Shanghai Entomological Museum (SEM).


Assuntos
Ortópteros , Distribuição Animal , Estruturas Animais , Animais , Tamanho Corporal , China , Masculino , Tamanho do Órgão
11.
ACS Nano ; 12(5): 4186-4193, 2018 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-29570267

RESUMO

Action potentials in neurons have been studied traditionally by intracellular electrophysiological recordings and more recently by the fluorescence detection methods. Here we describe a label-free optical imaging method that can measure mechanical motion in single cells with a sub-nanometer detection limit. Using the method, we have observed sub-nanometer mechanical motion accompanying the action potential in single mammalian neurons by averaging the repeated action potential spikes. The shape and width of the transient displacement are similar to those of the electrically recorded action potential, but the amplitude varies from neuron to neuron, and from one region of a neuron to another, ranging from 0.2-0.4 nm. The work indicates that action potentials may be studied noninvasively in single mammalian neurons by label-free imaging of the accompanying sub-nanometer mechanical motion.


Assuntos
Potenciais de Ação , Neurônios/fisiologia , Imagem Individual de Molécula/métodos , Animais , Células HEK293 , Hipocampo/citologia , Humanos , Fenômenos Mecânicos , Potenciais da Membrana , Movimento (Física) , Imagem Óptica/métodos , Ratos , Imagem Individual de Molécula/instrumentação
12.
Oncotarget ; 9(1): 75-82, 2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-29416597

RESUMO

Glycoconjugate vaccine is composed of polysaccharides (PSs) covalently linked with carrier protein. Glycosylation site selection, as a significant factor leading to heterogeneities of glycoconjugate structure, draws more and more attentions for its impact on the immunogenicity of glycoconjugate vaccine. To elucidate the relationship between glycosylation connectivity and immunogenicity of glycoconjugate vaccine, in this study, anti-E. coli O157:H7 glycoconjugate O-PS-MBP with defined connectivity, and three selected peptide segments GS1, GS2, GS3 derived from O-PS-MBP was synthesized. Immunogenicity results showed that only peptides adjacent to the glycosylation sites (GS1 and GS2) promoted the generation of PS-specific IgG antibodies and contributed to PS-specific IgG subclass distribution. Furthermore, GS1 and GS2 had significant priming effect for eliciting PS-specific IgG antibodies. These results indicated that different locations of glycosylation sites could lead to diverse presentation of peptides and glycopeptides to APCs and influence the immunogenicity of glycoconjugate vaccine, which extend the current understanding of mechanism for adaptive immune system activation by glycoconjugate vaccine, and have implications for rational glycoconjugate vaccine design.

13.
Carbohydr Polym ; 178: 221-227, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-29050588

RESUMO

Hyaluronan (HA) is a linear polysaccharide composed of repeating disaccharide units. It has been well documented to play an array of biological functions in cancer events. Here, we reported a sequential one-pot multienzyme (OPME) strategy for in vitro synthesis of HA and its derivatives. The strategy, which combined in situ sugar nucleotides generation with HA chain polymerization, could convert cheap monosaccharides into HA polymers without consuming exogenous sugar nucleotide donors. HA polymers (number-average molecular weight ranged from 1.5×104 to 5.5×105Da) with over 70% yields were efficiently synthesized and purified from this one-pot system. More importantly, partial labeled HA derivative was further synthesized by metabolic incorporation of unnatural monosaccharide analogues into the sequential OPME system. Cross-linked HA hydrogel was achieved via copper (I)-catalyzed azide-alkyne cycloaddition and exhibited novel networks consisting of both inter- and intra-connected HA chains, which could facilitate the potential applications of this unique polysaccharide.


Assuntos
Ácido Hialurônico/síntese química , Alquinos , Azidas , Química Click , Reação de Cicloadição , Enzimas/metabolismo , Hidrogéis , Peso Molecular , Polimerização
14.
Angew Chem Int Ed Engl ; 56(30): 8855-8859, 2017 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-28504338

RESUMO

Studying electrical activities in cells, such as action potential and its propagation in neurons, requires a sensitive and non-invasive analytical tool that can image local electrical signals with high spatial and temporal resolutions. Here we report a plasmonic-based electrochemical impedance imaging technique to study transient electrical activities in single cells. The technique is based on the conversion of the electrical signal into a plasmonic signal, which is imaged optically without labels. We demonstrate imaging of the fast initiation and propagation of action potential within single neurons, and validate the imaging technique with the traditional patch clamp technique. We anticipate that the plasmonic imaging technique will contribute to the study of electrical activities in various cellular processes.


Assuntos
Impedância Elétrica , Técnicas Eletroquímicas , Neurônios/química , Análise de Célula Única/métodos
15.
Sci Rep ; 7(1): 2048, 2017 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-28515441

RESUMO

Organisms served as factories of bio-assembly of nanoparticles attracted a lot of attentions due to the safe, economic and environmental-benignity traits, especially the fabrication of the super fluorescence properties quantum dots (QDs). However, information about the developmental dynamics of QDs in living organisms is still lacking. In this work, we synthesized cadmium-selenium (CdSe) QDs in Candida utilis WSH02-08, and then tracked and quantitatively characterized the developmental dynamics (photoactivation, photostable and photobleaching processes) of bio-QDs by translating fluorescence microscopy movies into visual quantitative curve. These findings shed light on the fluorescence properties of the bio-assembled QDs and are expected to accelerate the applications of the synthesized QDs in vivo. It provided a new way to screen bio-QDs and monitor the quality of QDs in vivo.


Assuntos
Compostos de Cádmio/metabolismo , Candida/metabolismo , Pontos Quânticos , Compostos de Selênio/metabolismo , Compostos de Cádmio/química , Fluorescência , Microscopia de Fluorescência , Pontos Quânticos/química , Pontos Quânticos/ultraestrutura , Compostos de Selênio/química , Espectrometria de Fluorescência
16.
Carbohydr Res ; 438: 39-43, 2017 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-27960098

RESUMO

The enzymatic synthesis of biologically important and structurally unique human P1PK blood group type P1 pentasaccharide antigen is described. This synthesis features a three-step sequential one-pot multienzyme (OPME) glycosylation for the stepwise enzymatic chain elongation of readily available lactoside acceptor with cheap and commercially available galactose and N-acetylglucosamine as donor precursors. This enzymatic synthesis provides an operationally simple approach to access P1 pentasaccharide and its structurally related Gb3 and P1 trisaccharide epitopes.


Assuntos
Acetilglucosamina/química , Antígenos de Grupos Sanguíneos/química , Galactose/química , Glicosiltransferases/metabolismo , Oligossacarídeos/síntese química , Glicosilação , Humanos
17.
Microb Cell Fact ; 15(1): 138, 2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27514820

RESUMO

BACKGROUND: In the process of ABO-incompatible (ABOi) organ transplantation, removal of anti-A and/or B antibodies from blood plasma is a promising method to overcome hyperacute rejection and allograft loss caused by the immune response between anti-A and/or B antibodies and the A and/or B antigens in the recipient. Although there are commercial columns to do this work, the application is still limited because of the high production cost. RESULTS: In this study, the PglB glycosylation pathway from Campylobacter jejuni was exploited to produce glycoprotein conjugated with Escherichia coli O86:B7 O-antigen, which bears the blood group B antigen epitope to absorb blood group B antibody in blood. The titers of blood group B antibody were reduced to a safe level without changing the clotting function of plasma after glycoprotein absorption of B antibodies in the plasma. CONCLUSIONS: We developed a feasible strategy for the specific adsorption/removal of blood group antibodies. This method will be useful in ABOi organ transplantation and universal blood transfusion.


Assuntos
Sistema ABO de Grupos Sanguíneos , Antígenos de Grupos Sanguíneos/química , Antígenos de Grupos Sanguíneos/imunologia , Epitopos , Escherichia coli/química , Antígenos O/química , Adsorção , Anticorpos/sangue , Coagulação Sanguínea , Transfusão de Sangue , Campylobacter jejuni/química , Campylobacter jejuni/genética , Escherichia coli/genética , Glicoproteínas/genética , Humanos , Transplante de Órgãos , Transplante Homólogo
18.
Ecotoxicology ; 24(10): 2175-80, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26410373

RESUMO

Microbial fuel cells (MFCs) have emerged as a promising technology for wastewater treatment with concomitant energy production but the performance is usually limited by low microbial activities. This has spurred intensive research interest for microbial enhancement. This study demonstrated an interesting stimulation effect of a static magnetic field (MF) on sludge-inoculated MFCs and explored into the mechanisms. The implementation of a 100-mT MF accelerated the reactor startup and led to increased electricity generation. Under the MF exposure, the activation loss of the MFC was decreased, but there was no increased secretion of redox mediators. Thus, the MF effect was mainly due to enhanced bioelectrochemical activities of anodic microorganisms, which are likely attributed to the oxidative stress and magnetohydrodynamic effects under an MF exposure. This work implies that weak MF may be applied as a simple and effective approach to stimulate microbial activities for various bioelectrochemical energy production and decontamination applications.


Assuntos
Fontes de Energia Bioelétrica , Biocombustíveis/análise , Campos Magnéticos , Eletricidade
19.
Carbohydr Res ; 413: 70-4, 2015 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-26101844

RESUMO

N-Acetylglucosamine-1-phosphate uridyltransferase (GlmU) is a bifunctional enzyme that catalyzes both acetyltransfer and uridyltransfer reactions in the prokaryotic UDP-GlcNAc biosynthesis pathway. Our previous study demonstrated that the uridyltransferase domain of GlmU (tGlmU) exhibited a flexible substrate specificity, which could be further applied in unnatural sugar nucleotides preparation. However, the structural basis of tolerating variant substrates is still not clear. Herein, we further investigated the roles of several highly conserved amino acid residues involved in substrate binding and recognition by structure- and sequence-guided site-directed mutagenesis. Out of total 16 mutants designed, tGlmU Q76E mutant which had a novel catalytic activity to convert CTP and GlcNAc-1P into unnatural sugar nucleotide CDP-GlcNAc was identified. Furthermore, tGlmU Y103F and N169R mutants were also investigated to have enhanced uridyltransferase activities compared with wide-type tGlmU.


Assuntos
Domínio Catalítico , Sequência Conservada , Escherichia coli K12/enzimologia , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Complexos Multienzimáticos/química , Complexos Multienzimáticos/metabolismo , Mutagênese Sítio-Dirigida , UDPglucose-Hexose-1-Fosfato Uridiltransferase/química , Acetilglucosamina/metabolismo , Biocatálise , Proteínas de Escherichia coli/genética , Modelos Moleculares , Complexos Multienzimáticos/genética , Mutação , Estrutura Secundária de Proteína
20.
Chem Commun (Camb) ; 51(36): 7689-92, 2015 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-25848722

RESUMO

Lacto-N-neotetraose and its sialyl and fucosyl derivatives including Lewis x (Le(x)) pentasaccharide, sialyl Lewis x (sLe(x)) hexasaccharide and internally sialylated derivatives were enzymatically synthesized from readily available lactoside, commercially available uridine 5'-diphosphate-glucose (UDP-Glc) and the corresponding monosaccharides using a highly efficient sequential one-pot multienzyme (OPME) strategy. The OPME strategy which combines bacterial glycosyltransferases and sugar nucleotide generation enzymes provides easy access to the biologically important complex oligosaccharides at preparative scale. Moreover, the same OPME strategy can be used for the regioselective introduction of sialic acid to the internal galactose unit of LNnT in a designed glycosylation route by simply changing the glycosylation sequence.


Assuntos
N-Acetilglucosaminiltransferases/metabolismo , Nucleotidiltransferases/metabolismo , Oligossacarídeos/biossíntese , Oligossacarídeos/química , Fosfotransferases/metabolismo , Bifidobacterium/enzimologia , Configuração de Carboidratos , Escherichia coli/enzimologia , Helicobacter pylori/enzimologia , Dados de Sequência Molecular
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