Anomalous Diffusion of Polyelectrolyte Segments on Supported Charged Lipid Bilayers.

This work provides mesoscale models for the anomalous diffusion of a polymer chain on a heterogeneous surface with rearranging randomly distributed adsorption sites. Both the "bead-spring" model and oxDNA model were simulated on supported lipid bilayer membranes with various molar fractions of charged lipids, using Brownian dynamics method. Our simulation results demonstrate that "bead-spring" chains exhibit sub-diffusion on charged lipid bilayers which agrees with previous experimental observations for short-time dynamics of DNA segments on membranes. In addition, the non-Gaussian diffusive behaviors of DNA segments have not been observed in our simulations. However, a simulated 17 base pairs double stranded DNA, using oxDNA model, performs normal diffusion on supported cationic lipid bilayers. Due to the number of positively charged lipids attracted by short DNA is small, the energy landscape that the short DNA experiences during diffusion is not as heterogeneous as that experienced by long DNA chains, which results in normal diffusion rather than sub-diffusion for short DNA.

Combined ReaxFF and Ab Initio MD Simulations of Brown Coal Oxidation and Coal-Water Interactions.

In this manuscript, we use a combination of Car-Parrinello molecular dynamics (CPMD) and ReaxFF reactive molecular dynamics (ReaxFF-MD) simulations to study the brown coal-water interactions and coal oxidation. Our Car-Parrinello molecular dynamics simulation results reveal that hydrogen bonds dominate the water adsorption process, and oxygen-containing functional groups such as carboxyl play an important role in the interaction between brown coal and water. The discrepancy in hydrogen bonds formation between our simulation results by ab initio molecular dynamics (CPMD) and that by ReaxFF-MD indicates that the ReaxFF force field is not capable of accurately describing the diffusive behaviors of water on lignite at low temperatures. The oxidations of brown coal for both fuel rich and fuel lean conditions at various temperatures were investigated using ReaxFF-MD simulations through which the generation rates of major products were obtained. In addition, it was observed that the density decrease significantly enhances the generation of gaseous products due to the entropy gain by reducing system density. Although the ReaxFF-MD simulation of complete coal combustion process is limited to high temperatures, the combined CPMD and ReaxFF-MD simulations allow us to examine the correlation between water adsorption on brown coal and the initial stage of coal oxidation.

Mesoscale Simulation of Bacterial Chromosome and Cytoplasmic Nanoparticles in Confinement.

In this study we investigated, using a simple polymer model of bacterial chromosome, the subdiffusive behaviors of both cytoplasmic particles and various loci in different cell wall confinements. Non-Gaussian subdiffusion of cytoplasmic particles as well as loci were obtained in our Langevin dynamic simulations, which agrees with fluorescence microscope observations. The effects of cytoplasmic particle size, locus position, confinement geometry, and density on motions of particles and loci were examined systematically. It is demonstrated that the cytoplasmic subdiffusion can largely be attributed to the mechanical properties of bacterial chromosomes rather than the viscoelasticity of cytoplasm. Due to the randomly positioned bacterial chromosome segments, the surrounding environment for both particle and loci is heterogeneous. Therefore, the exponent characterizing the subdiffusion of cytoplasmic particle/loci as well as Laplace displacement distributions of particle/loci can be reproduced by this simple model. Nevertheless, this bacterial chromosome model cannot explain the different responses of cytoplasmic particles and loci to external compression exerted on the bacterial cell wall, which suggests that the nonequilibrium activity, e.g., metabolic reactions, play an important role in cytoplasmic subdiffusion.

A Green-emitting Fluorescent Probe Based on a Benzothiazole Derivative for Imaging Biothiols in Living Cells.

A new green-emitting fluorescent probe 1 was developed for biothiol detection. The sensing mechanism was considered to be biothiol-induced cleavage of the 2,4-dinitrobenzene- sulfonate group in probe 1 and resulting inhibition of the probe's photoinduced electron transfer (PET) process. Probe 1 exhibited favorable properties such as excellent selectivity, highly sensitive (0.12 µM), large Stokes shift (117 nm) and a remarkable turn-on fluorescence signal (148-fold). Furthermore, confocal fluorescence imaging indicated that probe 1 was membrane-permeable and suitable for visualization of biothiols in living A549 cells.

Allelic and haplotype diversity of HLA-A, HLA-B and HLA-DRB1 gene at high resolution in the Nanning Han population.

The distribution of human leucocyte antigen (HLA) allele and haplotype varied among different ethnic populations. In this study, we investigated the allele and haplotype frequencies of HLA-A, HLA-B and HLA-DRB1 loci in the Nanning Han population who live in Guangxi province of China. We identified 26 HLA-A, 56 HLA-B and 31 HLA-DRB1 alleles in 562 Nanning individuals of Han ethnic group by sequence-based typing method. Of these, the three most common alleles in HLA-A, HLA-B and HLA-DRB1 loci, respectively, were A*11:01 (32.12%), A*02:07 (12.54%), A*24:02 (12.01%); B*46:01 (14.41%), B*15:02 (13.61%), B*40:01 (11.48%); DRB1*15:01 (14.15%), DRB1*16:02 (11.57%) and DRB1*12:02 (10.14%). With the exception of HLA-DRB1, the p values of the HLA-A and HLA-B loci showed that the HLA allelic distribution in this population was in accordance with Hardy-Weinberg expectation (p > 0.05). A total of 173 HLA~A-B~DRB1 haplotype with a frequency of >0.1% were presented and the three most common haplotype were HLA-A*33:03~B*58:01~DRB1*03:01 (6.12%), HLA-A*11:01~B*15:02~DRB1*12:02 (3.39%) and HLA-A*11:01~B*15:02~DRB1*15:01 (3.22%). The phylogenetic tree and the principal component analysis suggested that Nanning Han population had a relative close genetic relationship with Chinese Zhuang population and a relative distant genetic relationship with Northern Han Chinese. The information will be useful for anthropological studies, for HLA matching in transplantation and disease association studies in the Chinese population.

Near infrared electroluminescence of ZnMgO/InN core-shell nanorod heterostructures grown on Si substrate.

This paper presents a systematic investigation of a ZnMgO/InN core-shell nanorods heterojunction device on a p-Si substrate. Here we demonstrated the heteroepitaxial growth of the well-aligned ZnMgO/InN core-shell nanorods structure, which enabled an increased heterojunction area to improve the carrier injection efficiency of nanodevices by plasma-assisted molecular beam epitaxy combined with metal-organic chemical vapor deposition. In situ X-ray photoelectron spectroscopy measurements were performed on the ZnMgO nanorods, the interface of ZnMgO/InN and the InN core-shell nanorods to fully understand the structure and working mechanism of the heterojunction device. The current transport mechanism has been discussed in terms of the characteristics of current-voltage and the energy band diagram of the n-InN/ZnMgO/p-Si heterojunction. At a low forward voltage, the current transport followed the dependence of I ∼ V(1.47), which was attributed to the deep-level assisted tunneling. When the forward voltage was larger than 10 V, the current followed the relation of I ∼ V(2) because of the radiative recombination process. In accordance with the above conclusion, the near-infrared electroluminescence of the diode could be observed after the forward bias voltage up to 11.6 V at room temperature. In addition, the size quantization effect and the intrinsic electron accumulation of the InN core-shell nanorods were investigated to explain the blueshift and broadened bandwidth. Furthermore, the light output power of about 0.6 microwatt at a fixed wavelength of 1500 nm indicated that our study will further provide a useful route for realizing the near-infrared electroluminescence of InN on Si substrate.

[A novel CD36 mutation T538C (Trp180Arg) results in CD36 deficiency and establishment of a genotyping method for the novel mutation based on sequence-specific primer PCR].

OBJECTIVE: To explore the molecular basis for a CD36 deficiency individual and distribution of CD36 gene mutation in Guangxi population. METHODS: A female individual was studied. CD36 phenotype was detected by monoclonal antibody immobilization of platelet antigens assay (MAIPA) and flow cytometry (FCM). The coding regions of the CD36 gene were sequenced. A DNA-based polymerase chain reaction-sequence specific primer (PCR-SSP) assay was used to verify the identified mutation. Cell lines expressing the mutant and wild-type CD36[CD36(MT) and CD36(WT)] were established, with the expression of CD36 determined by Western blotting. The distribution of CD36 gene mutation was investigated among 1010 unrelated individuals with the PCR-SSP assay. RESULTS: Both MAIPA and FCM assays showed that the patient had type II CD36 deficiency. DNA sequencing showed that she has carried a heterozygous mutation T538C (Trp180Arg) in the exon 6 of CD36. Sequencing of cDNA clone confirmed that there was a nucleotide substitution at position 538 (538T>C). Western blotting also confirmed that the CD36 did not express on the CD36(MT) cell line that expressed the 538C mutant, but did express on the CD36(WT) cell line. The novel CD36 mutation T538C was further verified with 100% concordance of genotyping results by DNA-based PCR-SSP assay and 1010 unrelated individuals. No CD36 538C allele was detected among the 1010 individuals. CONCLUSION: This study has identified a novel CD36 mutation T538C(Trp180Arg)(GenBank: HM217022.1), and established a genotyping method for the novel sequence-specific primer PCR. The novel mutation is rare in Guangxi and can cause type II CD36 deficiency.

A Novel Fractional Brownian Dynamics Method for Simulating the Dynamics of Confined Bottle-Brush Polymers in Viscoelastic Solution.

In crowded fluids, polymer segments can exhibit anomalous subdiffusion due to the viscoelasticity of the surrounding environment. Previous single-particle tracking experiments revealed that such anomalous diffusion in complex fluids (e.g., in bacterial cytoplasm) can be described by fractional Brownian motion (fBm). To investigate how the viscoelastic media affects the diffusive behaviors of polymer segments without resolving single crowders, we developed a novel fractional Brownian dynamics method to simulate the dynamics of polymers under confinement. In this work, instead of using Gaussian random numbers ("white Gaussian noise") to model the Brownian force as in the standard Brownian dynamics simulations, we introduce fractional Gaussian noise (fGn) in our homemade fractional Brownian dynamics simulation code to investigate the anomalous diffusion of polymer segments by using a simple "bottle-brush"-type polymer model. The experimental results of the velocity autocorrelation function and the exponent that characterizes the subdiffusion of the confined polymer segments can be reproduced by this simple polymer model in combination with fractional Gaussian noise (fGn), which mimics the viscoelastic media.

[Two Novel Mutations at the CD36 Gene Splicing Sites and Their Molecular Basis for the CD36 Deficiency].

OBJECTIVE: To study two novel CD36 gene mutations at the CD36 splicing sites found in Guangxi population, as well as the molecular basis and population incidence of them. METHODS: DNA sequencing and cDNA clonal sequencing were used to detect CD36 exon sequence and the protein coding region sequence of CD36 mRNA for 2 CD36 deficient individuals (HHC and WGM) found in Guangxi population. Eukaryotic expression cell lines were established for the discovery of CD36 mRNA abnormal transcripts and Western blot assay was used to verify the effect of abnormal CD36 mRNA transcripts on CD36 expression. A DNA PCR-SSP genotyping method was established for the two CD36 novel mutations, and the population distribution was investigated among 110 CD36 deficient individuals in Guangxi region and 296 random individuals in Guangxi population. RESULTS: Novel mutation of c.430 -1G>C was found at the CD36 splicing site in HHC and WGM individuals, and novel mutation of c.1006 +2T>G at the CD36 splicing site was also found in the WGM individual. CD36 cDNA clonal sequencing showed that CD36 c.430 -1G>C could lead to the production of the two CD36 mRNA transcript variants: c.429_430insï¼»430-17_430-2;Cï¼½(p.Ala144fsTer1) and c.430_609del(p.Ala144_Pro203del)(GenBank:HM 217023.1); and CD36 c.1006 +2T>G could lead to the production of CD36 mRNA transcript variant of c.819_1006 del (p.Ser274GlufsTer16) (GenBank: HM217025.1). It was verified that all the three transcript variants could lead to CD36 deficiency by establishment of eukaryotic expression cell lines and Western blot assay. A study of the population incidence of two novel CD36 splicing site mutations found showed that in 110 CD36 deficient individuals and in 296 random individuals in Guangxi region, the mutation rate of CD36 c.430 -1G>C was 10.91% (12/110) and 1.35% (4/296), respectively, while CD36 c.1006 +2T>G was 2.73% (3/110) and 0 (0/296), respectively. CONCLUSION: This study identifies two novel CD36 mutations at CD36 splicing site, and preliminary clarified their molecular basis for the CD36 deficiency and the distribution characteristics in Guangxi population as well. It provides an experimental and theoretical basis for studying the molecular mechanism and characteristics of CD36 deficiency in Chinese population.

A Benzothiazole-based Ratiometric Fluorescent Probe for Benzoyl Peroxide and Its Applications for Living Cells Imaging.

We present herein a novel ratiometric fluorescent probe (1) for benzoyl peroxide (BPO). Probe 1 was obtained by coupling the recognition unit of arylboronate to a benzothiazole-derived fluorophore. The probe solution is colorless and displays weak blue fluorescence at 460 nm. Upon the addition of BPO, the arylboronate substituent can be removed via oxidation and 1,4-elimination processes. The released fluorophore emits strong yellow-greenish fluorescence at 546 nm. The ratiometric response of the probe is highly selective and sensitive for BPO. The dynamic range was fitted over 1.0 - 75.0 µM with a detection limit of 0.26 µM. In addition, the probe was applied to quantitative detection of BPO in real samples of wheat flour and an antimicrobial agent. Cellular experiments further demonstrated that probe 1 can be effectively utilized for imaging BPO in living cells.

A Turn-On Fluorescent Probe for Sensitive Detection of Cysteine in a Fully Aqueous Environment and in Living Cells.

We reported here a turn-on fluorescent probe (1) for the detection of cysteine (Cys) by incorporating the recognition unit of 2,4-dinitrobenzenesulfonyl ester (DNBS) to a coumarin derivative. The structure of the obtained probe was confirmed by NMR and HRMS techniques. The probe shows a remarkable fluorescence off-on response (∼52-fold) by the reaction with Cys in 100% aqueous buffer. The sensing mechanism was verified by the HPLC test. Probe 1 also displays high selectivity towards Cys. The detection limit was calculated to be 23 nM. Moreover, cellular experiments demonstrated that the probe is highly biocompatible and can be used for monitoring intracellular Cys.

[Anti-CD36 Mediated Platelet Transfusion Refractoriness and Related Cases After Stem Cell Transplantation].

OBJECTIVE: To analyse the cases of platelet transfusion refractoriness after received HLA-matched unrelated donor hematopoietic stem cell transplantation, to analyze and identify the phenotype and genotype of CD36 in both the patient and stem cell donor, as well as the characteristic of antibody induced platelet transfusion refractoriness, and to analyse the efficacy of matched CD36-deficiency platelets transfusions. METHODS: The CD36 expression on platelet and monocyte was analyzed by flow cytometry (FCM) in both patient and donor. Polymerase chain reaction sequence-based typing (PCR-SBT) was used to analyze the exons sequence of CD36 and HPA. Fast monoclonal antibody-specific immobilization of platelet antigen (F-MAIPA) and FCM were used to identify platelet antibodies in the patient. Short tandem repeat polymerase chain reaction (STR-PCR) was applied to monitor engraftment evidence. The platelet level was monitored. CD36- deficiency donor's platelets were selected from CD36- deficiency donor blood bank. RESULTS: The donor was CD36 positive and the patient was typed I CD36 deficiency. The anti-CD36 antibody was identified in patient's serum (after transplantation), while the HLA and HPA-related antibodies were excluded. Sequence analysis of CD36 exon in the patient showed Exon 6 -1G>C(Change in splicing site) homozygote, which was a novel CD36 mutation. STR, HPA and CD36 of the patient (complete chimerism) were conversed to that of donor gene types on day 18 after allo-HSCT. The positive CD36 expression on platelet and monocyte in the patient was observed on day 96 after allo-HSCT. The patient showed the platelet transfusion refractoriness which was significantly improved after platelets transfusions from CD36 deficiency donors. CONCLUSION: Stem cell transplants resulted in anti-CD36 and caused platelet transfusion refractoriness, that was first reported in China. To ensure the efficacy of platelet transfusion, the CD36-deficiency patient should receive CD36 deficiency platelets for transfusion.

Platelet Immunology in China: Research and Clinical Applications.

Immunization against human platelet alloantigens (HPAs) is associated with a number of clinical complications. The detection and identification of clinically relevant platelet antibodies are important for the diagnosis and management of patients affected with immune-mediated thrombocytopenias. Human platelet alloantigen frequencies and the characteristics of antiplatelet antibodies vary widely between ethnic groups. Since 2008, the importance of platelet immunology in the field of transfusion medicine has gained greater recognition by clinical laboratories in China. Laboratories in China have established and improved methods for platelet antibody detection and HPA genotyping techniques, which are used for the diagnosis of alloimmune platelet disorders in clinic and research environments. Research has revealed the frequencies of HPA alleles in different Chinese ethnic groups and compared the differences in HPA gene frequencies between the Chinese Han and other ethnic groups of the world. Production of anti-CD36 isoantibodies is an important risk factor for immune-mediated thrombocytopenia in the Chinese population. Advances in research and clinical application of platelet immunology have significantly improved the clinical diagnosis, treatment including transfusion support, and prevention of alloimmune platelet disorders in the Chinese population.

[The genetic polymorphisms of nine Y-STR loci with short fragment size alleles in southern Chinese Han population and its application in forensic science].

OBJECTIVE: To study the genetic polymorphisms of 9 Y-chromosome specific STR loci that the allele size is less than 180 bp in length in the southern Chinese Han population, and to utilize the studied result to forensic science. METHODS: Nine Y-STR loci were amplified by single multiplex PCR, and the PCR products were sequenced by using ABI Prism 3100 DNA Sequencer. The allele and haplotype frequencies at 9 Y-STR loci were determined in a total of 213 unrelated males from southern Chinese Han population. Eighty-four father/son pairs with demonstrated paternity and thirty-six non-paternity father/son pairs were detected by using our Y-STR multiplex system. RESULTS: Three Y-STR alleles for DYS426, five alleles for DYS393, DYS460, DYS391 and DYS389 I respectively, six alleles for DYS456, seven alleles for both H4 and DYS388, and eight alleles for DYS458 loci were detected in 213 unrelated male individuals. Except for the DYS426 locus with a low GD value of 0.1489, the GD values for other 8 Y-STR loci ranged from 0.5064 to 0.9133. A total of 178 haplotypes were found at 9 Y-STR loci, of which 154 haplotypes were observed only once, and the haplotype diversity was 0.9983. None of Y-STR allele mutation was observed in the 84 father/son pairs with demonstrated paternity. Among the 36 non-paternity father/son pairs, two cases could get the paternity exclusions at 2 Y-STR loci; and the paternity of 33 cases could be ruled out by 3 or more Y-STR loci; only one case was found no exclusion of paternity regardless of detecting 9 Y-STR loci. CONCLUSION: This result indicates that the 9 Y-STR loci with short fragment size alleles are highly polymorphic. The fluorescent multiplex amplification system that we developed is suitable for personal identification and paternity testing.

[Study on molecular genetic structure of Ael blood subgroup].

OBJECTIVE: To study the ABO allele molecular characteristics of Ael blood subgroup. METHODS: Five individuals of diagnosed as Ael blood subgroup were subjected to PCR amplify ABO alleles using four pairs of sequence-specific primers. Exon 6 and exon 7 at ABO locus of all samples were sequenced. An individual with AelB phenotype was chosen for further analysis of transcript structure of ABO gene. RESULTS: Sequence analysis indicated one Ael phenotype sample with reported Ael01 allele, one Ael phenotype sample with an Ael05 allele, and two AelB and one Ael individuals did not contain referred A allele, but contain O01 or O02 allele with 261G deletion. CONCLUSION: Molecular bases for the Ael have highly polymorphism. The mechanism responsible for the express weak A antigen of O allele with 261G deletion awaits to be elucidated.

[Identification of A Novel HLA-B*13:92 Allele and Analysis of Its 3D Model Structure].

OBJECTIVE: To identify a novel human leukocyte antigen (HLA) allele HLA-B*13:92 and analyze 3D model of HLA molecule. METHODS: Polymerase chain reaction sequencing-based (PCR-SBT) was used in routine HLA typing, the B locus typing results of one sample was one base mismatch with B*13:01:01, B*58:01:01 at locus 189, The Group Specific Sequencing Products (GSSP) which target at B*13 and B*58 were used to confirm difference between the new allele and highest homologous allele, then the new allele was modeled by Swiss-model to its 3D structure. RESULTS: The sequencing results showed that the new allele with highest homologous allele B*13:01:01 was the difference in the second exon at position 189 C>A (codon 39 GAC>GAA), 39 Asp (D) was changed to Glu (E). The amino acid substitution at residue 39 of the HLA polypeptide was located in α-helices of antigenic peptide-biding region. CONCLUSION: This allele is a new HLA-B allele found in Chinese Guangxi Zhang population and has been designated as HLA-B*13:92 by the World Health Organization (WHO) HLA Nomenclature Committee.

Identification of a novel B variant allele at the ABO locus in Chinese Han individuals with B subgroup.

We studied the molecular genetic background of the B subgroup in the Chinese Han population and identified a novel allele at the ABO locus. Ten control samples from randomly selected blood donors of normal B phenotype and 6 samples from individuals diagnosed as B subgroup by serological tests were genotyped by PCR-SSP and direct DNA sequencing at exons 6 and 7 of the ABO gene. Exons 6 and 7 and the intervening intron 6 of B alleles from the 6 B subgroup samples were analyzed by cloning and haplotype-sequencing. A novel B variant allele was identified in 2 individuals who were serologically-determined as members of the B(x) and B(w) subgroups, respectively. The novel B allele differs from allele B101 by a single 695T>C missense mutation in exon 7. The family of the individual with B(x) subgroup was studied; among 8 family members tested, 4 had the novel B variant allele. No mutation at exon 6 or 7 of the ABO gene was detected in the 10 control samples or in the other 4 B subgroup samples. Mutation at position 695 where T is replaced by C results in an amino acid change from Leu to Pro, which is predicted to diminish B transferase activity. This indicates that alteration of the amino acid at position 232 is critical to the activity of glycosyltransferases.

[Identification of a novel B variant allele in a Chinese Han individual with B subgroup].

OBJECTIVE: To study the molecular genetic background of B subtype in Chinese Han population and identify novel allele at the ABO locus. METHODS: Ten samples from randomly selected blood donors of normal B phenotype used as control, and six samples from individuals diagnosed as B subgroup by serological tests were genotyped by sequence specific primer polymerase chain reaction and direct DNA sequencing at the exons 6 and 7 of ABO gene. The exons 6 and 7 and the intervening intron 6 of the B allele from each B subgroup sample were analyzed by cloning and haplotype sequencing. RESULTS: A novel B variant allele was identified in two individuals whose blood samples were diagnosed as belonging to Bx subgroup and Bw subgroup respectively, the novel B allele being different from the allele B101 by single 695T>C missense mutation in exon 7. A family with the individual possessed Bx subgroup was studied. Among 22 family members tested, seven family members were found to carry the novel B variant allele. No novel point mutation at the exons 6 and 7 of ABO gene were detected in the ten control samples and the other four samples with B subgroup. CONCLUSION: The present authors define this allele as a novel B variant allele. The mutation of this novel allele, in which the nucleotide alters from T to C at position of 695 in exon 7 and hence results in an amino acid change from Leu to Pro, is expected to diminish the enzyme's activity. It indicates that the alteration of amino acid at the position of 232 is critical to the activity of glycosyltransferases.