Short-Term Outcomes of Transcatheter Aortic Valve Replacement in Low-Risk Patients With Pure Severe Aortic Regurgitation.

Transcatheter aortic valve replacement (TAVR) has emerged as an alternative treatment for patients with pure severe aortic regurgitation (PSAR) who are contraindicated for surgery or have a high surgical risk. However, the therapeutic efficacy and safety of TAVR in low Society of Thoracic Surgeons (STS) score risk patients remain to be clarified. This study aimed to explore the feasibility of TAVR treatment in different STS-risk patients and to compare the adverse events between the groups. In this study, patients with PSAR who underwent TAVR at Zhongshan Hospital, Fudan University, China, during the inclusion period were included and categorized into 3 groups based on STS scores. The baseline data, imaging results, and follow-up data of the patients were documented. Therefore, of 75 TAVR patients, 38 (50.7%) were categorized as low risk (STS <4), and 37 (49.3%) patients were categorized as intermediate and high risk (STS ≥4). Compared with patients at intermediate and high risk, those in the low-risk group were younger, had a lower body mass index, had a lower prevalence of hypertension, chronic obstructive pulmonary disease, and previous percutaneous coronary intervention, and had better cardiac function (p all <0.05). In the hospital and at the 1-month follow-up, the degree of aortic regurgitation and cardiac function were significantly improved. No significant difference was found between the 2 groups in the hospital or during the 30-day follow-up. In conclusion, TAVR for PSAR in low-STS-risk patients is safe and efficient during 30 days of follow-up compared with intermediate- and high-STS-risk groups. TAVR for PSAR should not be limited to inoperable or STS-defined high-risk patients. Long-term follow-up is needed for further investigation.

New classification system for radical rectal cancer surgery based on membrane anatomy.

BACKGROUND: Total mesorectal excision along the "holy plane" is the only radical surgery for rectal cancer, regardless of tumor size, localization or even tumor stage. However, according to the concept of membrane anatomy, multiple fascial spaces around the rectum could be used as the surgical plane to achieve radical resection. AIM: To propose a new membrane anatomical and staging-oriented classification system for tailoring the radicality during rectal cancer surgery. METHODS: A three-dimensional template of the member anatomy of the pelvis was established, and the existing anatomical nomenclatures were clarified by cadaveric dissection study and laparoscopic surgical observation. Then, we suggested a new and simple classification system for rectal cancer surgery. For simplification, the classification was based only on the lateral extent of resection. RESULTS: The fascia propria of the rectum, urogenital fascia, vesicohypogastric fascia and parietal fascia lie side by side around the rectum and form three spaces (medial, middle and lateral), and blood vessels and nerves are precisely positioned in the fascia or space. Three types of radical surgery for rectal cancer are described, as are a few subtypes that consider nerve preservation. The surgical planes of the proposed radical surgeries (types A, B and C) correspond exactly to the medial, middle, and lateral spaces, respectively. CONCLUSION: Three types of radical surgery can be precisely defined based on membrane anatomy, including nerve-sparing procedures. Our classification system may offer an optimal tool for tailoring rectal cancer surgery.

A prospective observational study on utility of serum mesencephalic astrocyte-derived neurotrophic factor as a promising prognostic biomarker of severe traumatic brain injury in humans.

BACKGROUND: Mesencephalic astrocyte-derived neurotrophic factor (MANF) is released under endoplasmic reticulum stress, thereby exerting neuroprotective effects. We determined whether serum MANF may be a prognostic biomarker of human severe traumatic brain injury (sTBI). METHODS: Serum MANF concentrations of 137 sTBI patients and 137 controls were quantified in this prospective cohort study. Patients with extended Glasgow outcome scale (GOSE) scores of 1-4 at post-traumatic 6 months were considered to have poor prognosis. Relationships between serum MANF concentrations and severity plus prognosis were investigated using multivariate analyses. Area under receiver operating characteristic curve (AUC) was calculated for reflecting prognostic efficiency. RESULTS: As compared to controls, there was a significant increase of serum MANF concentrations after sTBI (median, 18.5 ng/ml versus 3.0 ng/ml; P < 0.001), which was independently correlated with Glasgow coma scale (GCS) scores [ß, -3.000; 95% confidence interval (CI), -4.525--1.476; VIF, 2.216; P = 0.001], Rotterdam computed tomography (CT) scores (ß, 4.020; 95% CI, 1.446-6.593; VIF, 2.234; P = 0.002) and GOSE scores (ß, -0.056; 95% CI, -0.089--0.023; VIF, 1.743; P = 0.011). Serum MANF concentrations substantially distinguished risk of poor prognosis with AUC of 0.795 (95% CI, 0.718-0.859) and its concentrations > 23.9 ng/ml was predictive of poor prognosis with 67.7% sensitivity and 81.9% specificity. Serum MANF concentrations combined with GCS scores and Rotterdam CT scores displayed markedly higher prognostic predictive ability than each of them (all P < 0.05). Using restricted cubic spline, there was a linear correlation between serum MANF concentrations and poor prognosis (P = 0.256). Serum MANF concentrations > 23.9 ng/ml was independently associated with poor prognosis (odds ratio, 2.911; 95% CI, 1.057-8.020; P = 0.039). A nomogram was built, where serum MANF concentrations > 23.9 ng/ml, GCS scores and Rotterdam CT scores were integrated. Hosmer and Lemeshow test, calibration curve and decision curve analysis demonstrated such a prediction model was comparatively stable and was of relatively high clinical benefit. CONCLUSIONS: Substantially increased serum MANF concentrations after sTBI are highly correlated with traumatic severity and are independently predictive of long-term poor prognosis, suggesting that serum MANF may represent a useful prognostic biochemical marker of human sTBI.

Anomalous Structural Evolution and Glassy Lattice in Mixed-Halide Hybrid Perovskites.

Hybrid halide perovskites have emerged as highly promising photovoltaic materials because of their exceptional optoelectronic properties, which are often optimized via compositional engineering like mixing halides. It is well established that hybrid perovskites undergo a series of structural phase transitions as temperature varies. In this work, the authors find that phase transitions are substantially suppressed in mixed-halide hybrid perovskite single crystals of MAPbI3-x Brx (MA = CH3 NH3 + and x = 1 or 2) using a complementary suite of diffraction and spectroscopic techniques. Furthermore, as a general behavior, multiple crystallographic phases coexist in mixed-halide perovskites over a wide temperature range, and a slightly distorted monoclinic phase, hitherto unreported for hybrid perovskites, is dominant at temperatures above 100 K. The anomalous structural evolution is correlated with the glassy behavior of organic cations and optical phonons in mixed-halide perovskites. This work demonstrates the complex interplay between composition engineering and lattice dynamics in hybrid perovskites, shedding new light on their unique properties.

The Role of MOOC in Biochemistry Teaching: Teaching Practice and Summary of “MOOC + Online Meet Course” in Biochemistry of South China Agricultural University / 中国生物化学与分子生物学报

Biochemistry is not only a basic course for biology majors, but also one of the fastest growing frontier courses. Facing the complicated system of biochemistry, the traditional teaching mode exposes many problems, and the teaching effect is not good. With the development of Internet technology, " Internet +" education has developed rapidly. Online courses such as MOOCs and micro-courses provide many colleges and universities with rich learning resources. Online courses such as Dingding Classroom, Tengxun Classroom, Rain Classroom, and WeChat exchange platform also allow students to achieve synchronous learning conveniently. Online teaching has become the main teaching mode of colleges and universities across the country during the COVID-19 epidemic. However, after several years of promotion, pure online teaching has also exposed many problems in terms of teaching effect. In order to give full play to the respective advantages of online and offline teaching, blended teaching has become a new direction. South China Agricultural University began to cooperate with Wisdom Tree Platform in early 2019 to establish the MOOC of biochemistry. During the COVID-19 outbreak in 2020, the online mixed teaching mode of “MOOC + online meet course” is used in teaching. Teaching feedback results showed that "MOOC + online meet course" can be more generally recognized by students than relying solely on MOOC learning. This teaching mode improves students′ learning interest and initiative, improves teaching quality and learning effect, and provides a reference for the application of "MOOC + offline course" in the future.

Large-Area Crystalline Zeolitic Imidazolate Framework Thin Films.

We report that continuous MOF films with highly controlled thickness (from 44 to 5100 nm) can be deposited over length scales greater than 80 centimeters by a facile, fast, and cost-effective spray-coating method. Such success relies on our discovery of unprecedented perfectly dispersed colloidal solutions consisting of amorphous MOF nanoparticles, which we adopted as precursors that readily converted to the crystalline films upon low-temperature in situ heating. The colloidal solutions allow for the fabrication of compact and uniform MOF films on a great deal of substrates such as fluorine-doped tin oxide, glass, SiO2 , Al2 O3 , Si, Cu, and even flexible polycarbonate, widening their technological applications where substrates are essential. Despite the present work focuses on the fabrication of uniform cobalt-(2-methylimidazole)2 and zinc-(2-methylimidazole)2 films, our findings mark a great possibility in producing other high-quality MOF thin films on a large scale.

The Recent HIV-1 Infections in Blood Donors of Fuzhou Zone / 中国实验血液学杂志

OBJECTIVE@#To investigate the recent HIV-1 infections of the blood donors in Fuzhou zone.@*METHODS@#The positive HIV antibody confirmatory samples in Fuzhou zone from 2012 to 2016 were collected and tested by LAg-Avidity EIA, and HIV long-term infections or recent infections were determined.@*RESULTS@#405 371 cases of blood donors were tested in the period from 2012 to 2016, and 94 HIV confirmatory positive samples were collected. 35 cases were recent infections determined by LAg-Avidity EIA, the annual HIV-1 incidences were 1.326‰, 0.845‰, 0.694‰, 1.148‰ and 0.364‰, the average incidences were 0.863‰. Among 94 cases of HIV confirmatory positive donors，58 cases were first donors and 36 cases were repeated donors, 17(29.3%) and 18 (50.0%) cases were recent infections respectively, which showed statistical significance（χ@*CONCLUSION@#The HIV-1 incidences were stable among blood donors in Fuzhou zone. The percentage of HIV-1 recent infections in repeated donors were more higher than that in first donors.

Study on the relationship between personality characteristics and family environment of medical undergraduates taking psychology as an elective course / 四川精神卫生

ObjectiveTo analyze the correlation between personality characteristics and family environment of undergraduate medical students taking psychology course. MethodsIn June 2017， a cross-sectional survey was conducted among 67 undergraduate medical students taking psychology course， and all the selected individuals were assessed using Minnesota Multiphasic Personality Inventory （MMPI） and Family Environment Scale-Chinese Version （FES-CV）. Then Pearson correlation analysis was performed between the original scores of MMPI subscales and the scores of FES-CV subscales. ResultsThe scores of hypochondriasis， depression， hysteria， psychopathic deviate， masculine-femininity， paranoia， psychasthenia and schizophrenia in MMPI of undergraduates were all higher than those of the national norm， with statistical differences （t=2.070~8.350， P<0.05 or 0.01）. The scores of cohesion， intellectual-cultural orientation， organization and achievement orientation in FES-CV of undergraduates were all lower than those of the national norm， while the scores of conflict tendency was higher than that of the national norm， with statistical differences （P<0.05 or 0.01）. Correlation analysis showed that cohesion score in FES-CV was negatively correlated with the scores of correction， hypochondriasis， depression and hysteria in MMPI （r=-0.410~-0.331， P<0.01）. Conflict tendency score was positively correlated with the scores of hysteria and psychasthenia （r=0.315， 0.415， P<0.01）. Active-recreational orientation score was negatively correlated with hypochondriasis score （r=-0.367， P<0.01） and positively correlated with schizophrenia score （r=0.346， P<0.01）. Control score was positively correlated with hysteria score （r=0.366， P<0.01）. ConclusionUndergraduate medical students taking psychology courses exhibit neuropathic and paranoid personality characteristics， and the personality characteristics are closely related to family environment.

Nonsequential double ionization of alkaline-earth metal atoms by intense mid-infrared femtosecond pulses.

A systematic study of nonsequential double ionization (NSDI) of alkaline-earth metal atoms with mid-infrared femtosecond pulses is reported. We find that the measured NSDI yield shows a strong target dependence and it is more suppressed for alkaline-earth metal with higher ionization potential. The observation is attributed to the differences in the recollision induced excitation and ionization cross sections of alkaline-earth metals. This work indicates that NSDI of alkaline-earth metals can be generally understood within recollision picture and sheds light on ultrafast control of electron correlation and dynamics of ionic excited states during NSDI of atoms with complex structures.

Molecular characterization of a RNA polymerase (RNAP) II (DNA directed) polypeptide H (POLR2H) in Pacific white shrimp (Litopenaeus vannamei) and its role in response to high-pH stress.

RNA polymerase (RNAP) II (DNA-directed) (POLR2) genes are essential for cell viability under environmental stress and for the transfer of biological information from DNA to RNA. However, the function and characteristics of POLR2 genes in crustaceans are still unknown. In the present study, a POLR2H cDNA was isolated from Pacific white shrimp (Litopenaeus vannamei) and designated as Lv-POLR2H. The full-length Lv-POLR2H cDNA is 772 bp in length and contains a 32-bp 5'- untranslated region (UTR), a 284-bp 3'- UTR with a poly (A) sequence, and an open reading frame (ORF) of 456 bp encoding an Lv-POLR2H protein of 151 amino acids with a deduced molecular weight of 17.21 kDa. The Lv-POLR2H protein only contains one functional domain, harbors no transmembrane domains and mainly locates in the nucleus. The expression of the Lv-POLR2H mRNA was ubiquitously detected in all selected tissues, with the highest level in the gills. In situ hybridization (ISH) analysis showed that Lv-POLR2H was mainly located in the secondary gill filaments, the transcript levels of Lv-POLR2H in the gills were found to be significantly affected after challenge by pH, low salinity and high concentrations of NO2- and NH4+, indicating that Lv-POLR2H in gill tissues might play roles under various physical stresses. Specifically, under high-pH stress, knockdown of Lv-POLR2H via siRNA significantly decreased the survival rate of the shrimp, indicating its key roles in the response to high-pH stress. Our study may provide the first evidence of the role of POLR2H in shrimp responding to high-pH stress and provides new insight into molecular regulation in response to high pH in crustaceans.

Curcumin Inhibits the Proliferation, Migration, Invasion, and Apoptosis of Diffuse Large B-Cell Lymphoma Cell Line by Regulating MiR-21/VHL Axis

Analysis of pulmonary valve function in patients with tetralogy of Fallot after radical surgery / 中华心血管病杂志

Objective@#To analyze the pulmonary valve function in patients with tetralogy of Fallot after radical surgery.@*Methods@#Clinical data of 263 patients (119 male, mean age (33.2±11.5) years old) with tetralogy of Fallot underwent radical surgery in our hospital from January 2010 to June 2016 were retrospectively analyzed. According to age, patients were divided into 14-17 years old group (14 cases), 18-29 years old group (100 cases), 30-39 years old group (61 cases) and above 40 years old group (87 cases). The patients were divided into pulmonary regurgitation group (87 cases) and control group (176 cases) according to weather they have moderate or severe pulmonary regurgitation. Echocardiographic data were compared among groups.@*Results@#A total of 83 patients received re-operation. The median age of the primary radical operation was 9 (5, 13) years, and the median time from the primary radical operation to echocardiographic follow-up was 5 (1, 13) years. Among the 263 enrolled patients, prevalence of pulmonary regurgitation was 36.1% (95/263), and pulmonary stenosis was evidenced in 28 patients (10.6%). The ratio of moderate to severe tricuspid regurgitation was 14.3% (2/14), 27.0% (27/100), 32.8% (20/61) and 37.9% (33/87) in 14-17 years old group, 18-29 years old group, 30-39 years old group and above 40 years old group, respectively (P=0.029), while prevalence of moderate and severe pulmonary regurgitation, moderate and severe pulmonary valve stenosis, pulmonary valve transvalvular pressure >40 mmHg (1 mmHg=0.133 kPa), right atrial and right ventricular enlargement ratio were similar among groups (all P>0.05). The ratio of moderate and severe tricuspid regurgitation and right ventricular enlargement in the pulmonary regurgitation group was significantly higher than in the control group (40.2% (35/87) vs. 27.3% (48/176) and 96.6% (84/87) vs. 87.5% (154/176), all P<0.05), while left ventricular ejection fraction, right atrial enlargement, and right ventricular wall thickness were similar between the two groups (all P>0.05).@*Conclusion@#Pulmonary regurgitation is a common clinical feature among survivors of tetralogy of Fallot patients after radical surgery, and moderate to severe pulmonary regurgitation increases the risk of tricuspid regurgitation and enlargement of the right ventricle.

Recombinant Passenger Proteins Can Be Conveniently Purified by One-Step Affinity Chromatography.

Fusion tag is one of the best available tools to date for enhancement of the solubility or improvement of the expression level of recombinant proteins in Escherichia coli. Typically, two consecutive affinity purification steps are often necessitated for the purification of passenger proteins. As a fusion tag, acyl carrier protein (ACP) could greatly increase the soluble expression level of Glucokinase (GlcK), α-Amylase (Amy) and GFP. When fusion protein ACP-G2-GlcK-Histag and ACP-G2-Amy-Histag, in which a protease TEV recognition site was inserted between the fusion tag and passenger protein, were coexpressed with protease TEV respectively in E. coli, the efficient intracellular processing of fusion proteins was achieved. The resulting passenger protein GlcK-Histag and Amy-Histag accumulated predominantly in a soluble form, and could be conveniently purified by one-step Ni-chelating chromatography. However, the fusion protein ACP-GFP-Histag was processed incompletely by the protease TEV coexpressed in vivo, and a large portion of the resulting target protein GFP-Histag aggregated in insoluble form, indicating that the intracellular processing may affect the solubility of cleaved passenger protein. In this context, the soluble fusion protein ACP-GFP-Histag, contained in the supernatant of E. coli cell lysate, was directly subjected to cleavage in vitro by mixing it with the clarified cell lysate of E. coli overexpressing protease TEV. Consequently, the resulting target protein GFP-Histag could accumulate predominantly in a soluble form, and be purified conveniently by one-step Ni-chelating chromatography. The approaches presented here greatly simplify the purification process of passenger proteins, and eliminate the use of large amounts of pure site-specific proteases.

Fabrication of uniform 4H-SiC mesopores by pulsed electrochemical etching.

In this letter, the uniform 4H silicon carbide (SiC) mesopores was fabricated by pulsed electrochemical etching method. The length of the mesopores is about 19 µm with a diameter of about 19 nm. The introduction of pause time (T off) is crucial to form the uniform 4H-SiC mesopores. The pore diameter will not change if etching goes with T off. The hole concentration decreasing at the pore tips during the T off is the main reason for uniformity.

Influence of fibrinogen and laminin on bone mesenchymal stem cells osteogenic differentiation in PEGDA scaffold / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the effects of fibrinogen(FG) and laminin(LN) in promoting the osteogenic differentiation of bone mesenchymal stem cells(BMSCs)in PEGDA scaffold.</p><p><b>METHODS</b>After the rabbit BMSCs were isolated and cultured to passage 3. BMSCs were blended in PEGDA-FG or PEGDA-LN hydrogels and cultured for 7 days. The levels of osterix,osteopontin,osteocalcin,collagen 2,myocardin,PPARΓ,and integrins Α2,Α5,and Α6 in PEGDA-FG and PEGDA-LN constructs were determined. Immunohistochemistry was used to detect the expressions of myocardin,PPARΓ,and OPN in PEGDA-FG and PEGDA-LN constructs.</p><p><b>RESULTS</b>The expressions of osterix,OPN,and OC were significantly higher in PEGDA-FG scaffold than day 0(all P<0.05). The OPN and OC expression levels were significantly higher in PEGDA-LN scaffold than day 0(both P<0.05). In PEGDA-FG and PEGDA-LN scaffold,myocardin,PPARΓ and COL 2 expression level showed no significant differences than day 0(all P>0.05). Integrin Α2 was upregulated in PEGDA-LN scaffold than day 0(P<0.05). Integrin Α6 was upregulated in PEGDA-FG scaffold than day 0(P<0.05). Immunohistochemistry stain showed that OPN expression increased in PEGDA-FG and PEGDA-LN scaffolds.</p><p><b>CONCLUSION</b>FG and LN can promote rabbit BMSCs osteogenic differentiation in PEGDA three-dimensional scaffold.</p>

An accelerometer-based handheld system to reduce breaks in performance of young adults with cognitive impairments.

This study assessed the possibility of training two individuals with cognitive impairments using a system that reduced breaks in performance. This study was carried out according to an ABAB sequence in which A represented the baseline and B represented intervention phases. Data showed that the two participants significantly increased their target response, thus reducing breaks and improving vocational job performance during the intervention phases. Practical and developmental implications of the findings are discussed.

A cost-effective high-resolution melting approach using the EvaGreen dye for DNA polymorphism detection and genotyping in plants.

High-resolution melting (HRM) analysis relies on the use of fluorescent dyes, such as LCGreen, ResoLight, and SYTO9, which bind in a saturated manner to the double-stranded DNAs. These dyes are expensive in use and may not be affordable when dealing with a large quantity of samples. EvaGreen is a much cheaper DNA helix intercalating dye and has been used in quantitative real-time polymerase chain reaction (PCR) and post-PCR DNA melt curve analysis. Here we report on the development of an EvaGreen-based HRM analysis and its performance, in comparison with the popular LCGreen-based HRM analysis, in detection of DNA polymorphism in plants. We found that various polymorphisms ranged from single nucleotide polymorphisms (SNPs) to Indels were equally detected by using EvaGreen- or LCGreen-based HRM. EvaGreen dye was sensitive enough in discovery of SNPs in fivefold pooled samples. Using this economical dye we successfully identified multiple novel mutant alleles of Gln1-3 gene, which produces a cytosolic glutamine synthetase isoenzyme (GS1), in a maize ethyl methanesulfonate (EMS)-mutagenized library, and genotyped rice mapping populations with SNP markers. The current results suggest that EvaGreen is a promising dye for HRM analysis for its ease to use and cost effectiveness.

Modeling dendritic arborization based on 3D-reconstructions of adult rat phrenic motoneurons

Stereological techniques that rely on morphological assumptions and direct three-dimensional (3D) on focal measurements have been previously used to estimate the dendritic surface areas of phrenic motoneurons (PhrMNs). Given that97% of a motoneuron’s receptive area is provided by dendrites, dendritic branching and overall extension are physiologically important in determining the output of their synaptic receptive fields. However, limitations intrinsic to shape-based estimations and incomplete labeling of dendritic trees by retrograde techniques have hindered systematic approaches to examine dendritic morphology of PhrMNs. In this study, a novel method that improves dendritic filling of PhrMNs in lightly-fixed samples was used. Confocal microscopy allowed accurate 3D reconstruction of dendritic arbors from adult rat PhrMNs. Following pre-processing,segmentation was semi-automatically performed in 3D, and direct measurements of dendritic surface area were obtained. A quadratic model for estimating dendritic tree surface area based on measurements of primary dendrite diameter was derived (r2 =0.932; p<0.0001). This method may enhance interpretation of motoneuron plasticity in response to injury or disease by permitting estimations of dendritic arborization of PhrMNs since measurements of primary dendrite diameter can be reliably obtained from a number of retrograde labeling techniques

El área superficial de las dendritas en motoneuronas frénicas (PhrMNs) ha sido estimada anteriormente mediante técnicas estereológicas basadas en suposiciones geométricas, y medida en tres dimensiones (3D) utilizando microscopía confocal. Dado que el 97% del área receptora de una motoneurona corresponde a sus dendritas, la ramificación y extensión dendrítica son fisiológicamente importantes para determinar la salida de sus campos receptivos. Sin embargo, limitaciones inherentes a las estimaciones basadas en morfología neuronal y la tinción incompleta de los árboles dendríticos mediante técnicas retrógradas han dificultado los estudios sistemáticos de la morfología dendrítica en PhrMNs. En este estudio, se utilizó una nueva técnica que mejora la tinción dendrítica de las PhrMNs en preparaciones fijadas ligeramente. La reconstrucción dendrítica en 3D se logró con gran precisión utilizando microscopía confocal en PhrMNs de ratas adultas. Luego de una etapa de pre-procesamiento, la segmentación de los árboles dendríticos se realizó semi-automáticamente en 3D y usando mediciones directas del área superficial, se derivó un modelo cuadrático para estimar dicha área partiendo del diámetro de la dendrita primaria (r2 = 0.932; p<0.0001). Este método podría mejorar la evaluación de la plasticidad neuronal en respuesta a trauma u otras enfermedades permitiendo la estimación de la arborización dendrítica en PhrMNs, ya que el diámetro de la dendrita primaria puede obtenerse confiablemente de numerosas técnicas de tinción retrógrada

Constitutive plasma membrane targeting and microdomain localization of Dok5 studied by single-molecule microscopy.

In the present study, single-molecule fluorescence microscopy was used to examine the characteristics of plasma membrane targeting and microdomain localization of enhanced yellow fluorescent protein (eYFP)-tagged wild-type Dok5 and its variants in living Chinese hamster ovary (CHO) cells. We found that Dok5 can target constitutively to the plasma membrane, and the PH domain is essential for this process. Furthermore, single-molecule trajectories analysis revealed that Dok5 can constitutively partition into microdomain on the plasma membrane. Finally, the potential mechanism of microdomain localization of Dok5 was discussed. This study provided insights into the characteristics of plasma membrane targeting and microdomain localization of Dok5 in living CHO cells.

Heterodimerization of integrin Mac-1 subunits studied by single-molecule imaging.

Heterodimerization of integrin Mac-1 (alpha(M)beta(2)) subunits plays important role on regulating leukocytes adhesion to extracellular matrix or endothelial cells. Here, using total internal reflection microscopy, we investigated the heterodimerization of integrin Mac-1 subunits at the single-molecule level in live cells. Individual alpha(M) subunit fused to the enhanced yellow fluorescent protein (eYFP) was imaged at the basal plasma membrane of live Chinese hamster ovary (CHO) cells. Through analysis of mean square displacement (MSD), diffusion coefficient, the size of restricted domain and fraction of molecules undergoing restricted diffusion, we found that as compared with the diffusion in the absence of beta(2) subunit, the diffusion of single-molecule of alpha(M)-YFP was suppressed significantly in the presence of beta(2) subunit. Thus, based on the oligomerization-induced trapping model, we suggested that in the presence of beta(2) subunit, the alpha(M) subunit may form heterodimer with it.