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Search Results: 1 - 10 of 127016 matches for " Zaixin Li "
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Spectral properties of LH2 exhibit very similar even when heterologously express LH2 with β-subunit fusion protein in Rhodobacter sphaeroides  [PDF]
Zhiping Zhao, Xin Nie, Zongli Hu, Guoping Chen, Zaixin Li, Zhi Zhang
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.31013

Interactions between the light-harvesting subunits and the non-covalently bound photopigments attribute considerably to the spectral properties of photosynthetic bacteria light-harvesting complexes. In our previous studies, we have constructed a novel Rhodobacter sphaeroides expression system. In the present study, we focus on the spectral properties of LH2 when heterologously express LH2 with β-subunit- GFP fusion protein in Rb. sphaeroides. Near infra-red spectrum of LH2 remained nearly unchanged as measured by spectroscopy. Fluorescence spectrum suggested that the LH2 with β-subunit-GFP fusion protein complexes still possessed normal activity in energy transfer. However, photopigments contents were significantly decreased to a very low level in the LH2 with β-subunit-GFP fusion protein complexes compared to that of LH2. FT-IR spectra indicated that interactions between photopigments and LH2 α/β- subunits appeared not to be changed. It was concluded that the LH2 spectral properties exhibited very similar even when heterologously expressed LH2 b-subunit fusion protein in Rb. sphaeroides. Our present study may supply a new insight into better understand the interactions between light-harvesting subunits and photopigments and bacterial photosynthesis and promote the development of the novel Rb. sphaeroides expression system.

Amino terminus mutant OmpA from an isolated antibiotic resistant Escherichia coli still possess resistance to environmental stresses  [PDF]
Zhiping Zhao, Xin Nie, Zaixin Li, Zhi Zhang, Jie Ding, Wanru Xie
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.31014

Antibiotic resistant Escherichia coli strains are becoming more common recently. OmpA is a very important antigen protein of E. coli, which consists of two separate domains, N-terminal and C-terminal domain. The N-terminal domain contains eight β- barrel regions that plays important roles in the multifaceted functions of OmpA. In the present study, we cloned a mutant OmpA gene from a multi-antibiotic resistant E. coli strain. Sequence analysis indicated that the N-terminal DNA sequence of the mutant OmpA shared 81.05% homology with the modeled OmpA from E. coli K12 and the N-terminal amino acid sequence of the mutant OmpA was 81.22% identical to that of the E. coli K12 OmpA. Moreover, several amino acids located in the β-barrel region were mutated. The mutant OmpA was expressed in BL21 suggested by SDS-PAGE. Resistance to environmental stress assay indicated that the N-terminus mutant OmpA still possessed excellent activities in pH, temperature and osmotic pressure resistance. Our pre- sent study may supply insights into better and deeper understand the relationships between OmpA N-terminal regions and its functions in environmental stress conditions and the mechanisms on antibiotic resistance of E. coli.

Algebraic encoding and protein secondary structure prediction
Haiyan Zhang,Jinshan Zhang,Zaixin Li
International Journal of Algebra , 2012,
The comparison of the efficacy of swine FMD vaccine emulsified with oil adjuvant of ISA 201 VG or ISA 206 VG  [PDF]
Dong Li, Chunxue Zhou, Daliang She, Pinghua Li, Pu Sun, Xingwen Bai, Yingli Chen, Baoxia Xie, Zaixin Liu
Journal of Biosciences and Medicines (JBM) , 2013, DOI: 10.4236/jbm.2013.13005

The Seppic Company developed a new adjuvant Montanide ISA 201 VG, the upgraded version of Montanide ISA 206 VG, which keep the advantage and added some chemical components on the basis of ISA 206 to improve the cellular responses. The aim of the study is to compare the efficacy of swine FMD (foot-and-mouth) vaccine emulsified with oil adjuvant of ISA 201 or ISA 206 respectively. The pigs were vaccinated with FMD vaccine emulsified with inactive FMD type O antigen and adjuvant ISA 201 or ISA 206 respectively, according to 2.0 ml (1/1 dose), 0.67 ml (1/3 dose), 0.22 ml (1/9 dose) to calculate their PD50. The sera were collected from the vaccination of the day 0, 3, 7, 14, 21, 28 and the ELISA FMD type O antibody were detected. Furthermore, the PD50 were calculated after the pigs were challenged with virulent FMDV type O on 28 days post vaccination. The ELISA antibody titers of 201vaccine were significantly higher than that of 206 (except the third time). The fifty percent of protection dose (PD50) of 201 vaccine (PD50 = 15.59) was higher than that of 206 vaccine (PD50 = 10.05). The above data showed that the efficacy of the FMD vaccine emulsified with ISA 201 was better than which with ISA 206.

Expression and Stability of Foreign Epitopes Introduced into 3A Nonstructural Protein of Foot-and-Mouth Disease Virus
Pinghua Li, Xingwen Bai, Yimei Cao, Chenghao Han, Zengjun Lu, Pu Sun, Hong Yin, Zaixin Liu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041486
Abstract: Foot-and-mouth disease virus (FMDV) is an aphthovirus that belongs to the Picornaviridae family and causes one of the most important animal diseases worldwide. The capacity of other picornaviruses to express foreign antigens has been extensively reported, however, little is known about FMDV. To explore the potential of FMDV as a viral vector, an 11-amino-acid (aa) HSV epitope and an 8 aa FLAG epitope were introduced into the C-terminal different regions of 3A protein of FMDV full-length infectious cDNA clone. Recombinant viruses expressing the HSV or FLAG epitope were successfully rescued after transfection of both modified constructs. Immunofluorescence assay, Western blot and sequence analysis showed that the recombinant viruses stably maintained the foreign epitopes even after 11 serial passages in BHK-21 cells. The 3A-tagged viruses shared similar plaque phenotypes and replication kinetics to those of the parental virus. In addition, mice experimentally infected with the epitope-tagged viruses could induce tag-specific antibodies. Our results demonstrate that FMDV can be used effectively as a viral vector for the delivery of foreign tags.
Genetic characterization of the cell-adapted PanAsia strain of foot-and-mouth disease virus O/Fujian/CHA/5/99 isolated from swine
XingWen Bai, HuiFang Bao, PingHua Li, Pu Sun, WenDong Kuang, YiMei Cao, ZengJun Lu, ZaiXin Liu, XiangTao Liu
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-208
Abstract: To investigate the distinct biological properties, we performed plaque assay, estimated the pathogenicity in suckling mice and determined the complete genomic sequence of FMDV swine-isolated O/Fujian/CHA/5/99 strain. In addition, a molecular modeling was carried out with the external capsid proteins.The pathogenicity study showed that O/Fujian/CHA/5/99 had high virulence with respect to infection in 3-day-old suckling-mice (LD50 = 10-8.3), compared to O/Tibet/CHA/1/99 (LD50 = 10-7.0) which isolated from bovine. The plaque assay was distinguishable between O/Fujian/CHA/5/99 and O/Tibet/CHA/1/99 by their plaque phenotypes. O/Fujian/CHA/5/99 formed large plaque while O/Tibet/CHA/1/99 formed small plaque.The 8,172 nucleotides (nt) of O/Fujian/CHA/5/99 was sequenced, and a phylogenetic tree was generated from the complete nucleotide sequences of VP1 compared with other FMDV reference strains. The identity data showed that O/Fujian/CHA/5/99 is closely related to O/AS/SKR/2002 (94.1% similarity). Based on multiple sequence alignments, comparison of sequences showed that the characteristic nucleotide/amino acid mutations were found in the whole genome of O/Fujian/CHA/5/99.Our finding suggested that C275T substitution in IRES of O/Fujian/CHA/5/99 may induce the stability of domain 3 for the whole element function. The structure prediction indicated that most of 14 amino acid substitutions are fixed in the capsid of O/Fujian/CHA/5/99 around B-C loop and E-F loop of VP2 (antigenic site 2), and G-H loop of VP1 (antigenic site 1), respectively. These results implicated that these substitutions close to heparin binding sites (E136G in VP2, A174 S in VP3) and at antigenic site 1 (T142A, A152T and Q153P in VP1) may influence plaque size and the pathogenicity to suckling mice.The potential of genetic characterization would be useful for microevolution and viral pathogenesis of FMDV in the further study.Foot-and-mouth disease (FMD) is an acute, highly contagious viral disease of clov
Evaluation of a genetically modified foot-and-mouth disease virus vaccine candidate generated by reverse genetics
Pinghua Li, Xingwen Bai, Pu Sun, Dong Li, Zengjun Lu, Yimei Cao, Yuanfang Fu, Huifang Bao, Yingli Chen, Baoxia Xie, Zaixin Liu
BMC Veterinary Research , 2012, DOI: 10.1186/1746-6148-8-57
Abstract: The present study describes the generation of a full-length infectious cDNA clone of FMDV vaccine strain and a genetically modified virus with some amino acid substitutions in antigenic sites 1, 3, and 4, based on the established infectious clone. The recombinant viruses had similar growth properties to the wild O/HN/CHA/93 virus. All swine immunized with inactivated vaccine prepared from the O/HN/CHA/93 were fully protected from challenge with the viruses of ME-SA and SEA topotypes and partially protected against challenge with the virus of CHY topotype at 28?days post-immunization. In contrast, the swine inoculated with the genetically modified vaccine were completely protected from the infection of viruses of the three topotypes.Some amino acid substitutions in the FMDV vaccine strain genome did not have an effect on the ability of viral replication in vitro. The vaccine prepared from genetically modified FMDV by reverse genetics significantly improved the protective efficacy to the variant of the CHY topotype, compared with the wild O/HN/CHA/93 virus. Thus, the full-length cDNA clone of FMDV can be a useful tool to develop genetically engineered FMDV vaccine candidates to help control porcinophilic FMD epidemics in China.Foot-and-mouth disease (FMD) is a highly contagious vesicular disease of domestic and wild cloven-hooved animal species, which is caused by the foot-and-mouth disease virus (FMDV), the prototype member of the genus Aphthovirus of the family Picornaviridae. The highly contagious nature of FMDV and the associated high morbidity and productivity losses make it one of the most important barriers to the world trade of live animals and animal products. Control of the disease has been based on large-scale vaccinations with whole-virus inactivated vaccines, limitation of animal movements and destruction of herds exposed to the virus [1,2]. The currently available vaccine shows generally good protection against infection with the homologous and antigenic
Polymorphic genetic characterization of the ORF7 gene of porcine reproductive and respiratory syndrome virus (PRRSV) in China
Xiaofang Hao, Zengjun Lu, Wendong Kuang, Pu Sun, Yu Fu, Lei Wu, Qing Zhao, Huifang Bao, Yuanfang Fu, Yimei Cao, Pinghua Li, Xingwen Bai, Dong Li, Zaixin Liu
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-73
Abstract: Preliminary analysis indicated that highly pathogenic PRRSV strains with a 30-amino acid deletion in the Nsp2 protein are the dominant viruses circulating in China. Further analysis based on ORF7 sequences revealed that all Chinese isolates were divided into 5 subgroups, and that the highly pathogenic PRRSVs were distantly related to the MLV or CH-1R vaccine, raising doubts about the efficacy of these vaccines. The ORF7 sequence data also showed no apparent associations between geographic or temporal origin and heterogeneity of PRRSV in China.These findings enhance our knowledge of the genetic characteristics of Chinese PRRSV isolates, and may facilitate the development of effective strategies for monitoring and controlling PRRSV in China.Porcine reproductive and respiratory syndrome (PRRS) is a severe disease characterized by reproductive disorders in gilts and sows, especially during late gestation, and by respiratory distress in pigs. The disease first emerged in late 1987 in the United States [1] and three years later in Europe [2]. Porcine reproductive and respiratory syndrome virus (PRRSV), the causative agent of PRRS, belongs to the family Arteriviridae in the order Nidovirales [3], and is an enveloped virus with a single-stranded positive sense RNA genome containing nine open reading frames (ORFs) [4]. The ORFs 1a and 1b encode the non-structural proteins Nsp1a, Nsp1b, and Nsp2-12, while ORF2a, ORF2b, and ORFs 3-7 encode the structural proteins GP2a, GP2b, GP3, GP4, GP5, M, and N, respectively [5].Two genotypes are recognized for PRRSV, the North American type and the European type, as represented by the prototypes VR-2332 and Lelystad virus (LV), respectively [6]. Significant genetic differences have been described both between these two genotypes and within the same genotype of PRRSV [7-9].Since the first report of PRRSV in China in 1996 [10], the North American type PRRSV, with considerable genetic variation, has spread throughout the country [11-13]. Sin
Phylogenetic analysis of porcine parvoviruses from swine samples in China
Xiaofang Hao, Zengjun Lu, Pu Sun, Yuanfang Fu, Yimei Cao, Pinghua Li, Xingwen Bai, Huifang Bao, Baoxia Xie, Yingli Chen, Dong Li, Zaixin Liu
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-320
Abstract: Phylogenetic analysis shows that the PPV sequences are divided into four groups. The early Chinese PPV isolates are Group I viruses, and nearly all of the later Chinese PPV isolates are Group II viruses. LZ belongs to group II, whereas the JY strain is a Group III virus. This is the first report on the isolation of a Group III virus in China. The detection of selective pressures on the PPV genome shows that the NS1 and VP2 genes are under purifying selection and positive selection, respectively. Moreover, the amino acids in the VP2 capsid are highly variable because of the positive selection.Our study provides new molecular data on PPV strains in China, and emphasizes the importance of etiological studies of PPV in pigs.From a worldwide perspective, the porcine parvovirus (PPV) is one of the most common viral causes of porcine reproductive failure. PPV is of the genus Parvovirus, a group of viruses of that also infect cattle, cats, dogs, geese, rats, mice, mink, and raccoons. Although PPV is distinguishable from parvoviruses of all other species, it is antigenically related to other parvoviruses such as the canine parvovirus (CPV) and the feline panleukopenia virus (FPV) [1]. The PPV genome is a single strand DNA with a terminal palindromic structure. Its size is about 5 kb. The PPV particle is composed of three viral polypeptides, VP1, VP2, and VP3, with molecular weights of 83, 64, and 62 kDa, respectively. In vitro expression of the VP2 gene may spontaneously form the capsid. The structure of the VP2 capsid was resolved using X-ray crystallography and was found to be similar to the CPV, FPV, and minute viruses of mice (MVM) [2]. Pigs immunized with these virus-like particles mounted an immune response identical to that toward commercial vaccines [3]. Recently, the genome of PPV was found to contain a small open reading frame, designated as SAT, with a start codon downstream of the VP2 initiation codon [4]. In addition to these capsid proteins, some nonstructural
Evolution and molecular epidemiology of foot-and-mouth disease virus in China
XingWen Bai,PingHua Li,HuiFang Bao,ZaiXin Liu,Dong Li,ZengJun Lu,YiMei Cao,YouJun Shang,JunJun Shao,HuiYun Chang,JianXun Luo,XiangTao Liu
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4563-3
Abstract: Foot-and-mouth disease (FMD), caused by foot-and-mouth disease virus (FMDV), is considered one of the most important viral diseases of cloven-hoofed animals, causing severe economic losses in affected regions of the world. Three serotypes (A, O, and Asia 1) of FMDV have been identified in China since 1958. In addition, the occurrence of novel subtypes within these serotypes has made the epidemiology of FMDV more complicated over the last few years. In this review, we summarize the history and the current epidemiological situation in China, genetic diversity (e.g., quasispecies dynamics, antigenic heterogeneity, and functional constraints), intertypic recombination, and the evidence for positive selection of different FMDV serotypes. We also assess these genetic data to understand the origin, evolution, and transmission of FMDV, the findings of which may be useful in developing control measures for future epidemics.
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