Biomedical subjects

Ning Ling

Publications and source records attributed to Ning Ling.

12 recordsLinked to original sources

PubMed2026

Decoding microbial metabolic complementarity from individual traits to community structuring.

A fundamental challenge in microbiome research lies in elucidating the functional capacity of microbial communities through community membership and genomic data. As community structuring and emergent functional traits are determined by bacterial community metabolic networks, it is important to gain insights into the principles that govern bacteria-bacteria interactions. Here, we applied an integrative framework linking individual strain-level traits to community structuring in a simplified synthetic bacterial community (SSC8) that promotes the growth of ungrafted watermelon. By combining mono- and coculture assays with genome-scale metabolic modeling and metabolomic profiling of spent media, we characterized directional interactions and resource dependencies among community members. Our findings show that positive interactions dominated the community network, accounting for 55% of all pairwise combinations, indicating a high prevalence of growth-promoting effects among strains. Genome-scale metabolic modeling showed that functional divergence among strains enhanced the potential for metabolic complementarity as phylogenetic distance increased. Integrating metabolic modeling with metabolomics further suggested that Pseudomonas azotifigens Q6 not only benefited from all other community members, but also exhibited mutualistic interactions with the other three strains, with metabolite exchange involving compounds such as L-lysine and L-cysteine. Pseudomonas azotifigens Q6 acted as an important driver of community composition by affecting the abundance of several other consortium members in vitro. These findings highlight the role of metabolic complementarity in driving community structuring by promoting selective persistence of specific strains. Our work provides mechanistic insights into microbial interaction networks in vitro and offers a conceptual foundation for the rational design of functionally robust and plant-beneficial microbiomes.

Bacteria↗

PubMed2006

Novel vaccines for the treatment of chronic HBV infection based on mycobacterial heat shock protein 70.

Immunogenic peptide-based vaccines can raise significant cellular immune responses. Although cytotoxic T lymphocytes (CTL) peptide epitopes are generally poor immunogens, heat shock protein 70 from Mycobacterium tuberculosis (TBhsp70) can overcome this problem since it is a potent adjuvant that links innate and adaptive immune responses. Our goal is to use TBhsp70 as an adjuvant for development of therapeutic vaccines for chronic Hepatitis B virus infection (HBV). To this end, we genetically fused the HBV core 18-27 peptide (HBcAg((18-27))) as a CTL epitope to the C-terminus of TBhsp70 and expressed the resulting protein in methylotropic yeast Pichia pastoris GS115. At the same time, the TBhsp70-HBcAg((18-27)) peptide complex was reconstituted in vitro. We investigated whether TBhsp70-peptide complex and TBhsp70-peptide fusion protein could generate antigen specific CTL responses in vitro. Dendritic cells (DC) from HLA-A2(+) chronic HBV infection and healthy control pulsed with two vaccines were studied phenotypically by FACS analyses and functionally by cytokine release, and HBV-specific CTL response. Our results demonstrate that two vaccines can activate DC of chronic HBV infection and healthy control by upregulation CD40 and CD86, high production of IL-12p70 and TNF-alpha. Furthermore, autologous T cells with DC stimulated by two vaccines can produce IFN-gamma and generate HBV-specific CTL response. However, capacity for CTL response and cytokines production from HBV infections remained inferior to that of healthy controls. Thus, the strategy of utilizing TBhsp70 may provide a novel design for the development of prophylactic and therapeutic vaccines.

Adolescent↗

PubMed2005

A Quasi species of the pre-S/S gene and mutations of enhancer II/core promoter/pre-C in mothers and their children infected with hepatitis B virus via mother-to-infant transmission.

BACKGROUND: Hepatitis B virus (HBV) infection has a tendency to be chronic. The quasi species of HBV in the pre-S/S gene and mutations in enhancer II (EnhII)/core promoter (CP)/pre-C of HBV were studied in asymptomatic carrier (AsC) mothers and their children with different virus loads, to gain a better understanding of the pathogenic mechanisms of HBV. METHODS: Quasi species were analyzed using an established phylogenetic tree based on the sequences of the pre-S/S gene from 3 mother-child pairs. The mutations of EnhII/CP/pre-C were studied in 15 mother-child pairs. RESULTS: Substitution was the main mutation model. The phylogenetic tree indicated that the pre-S/S gene in every mother-child pair had the same root. The sequences of the pre-S/S gene of each patient were somewhat different from one another, but there was limited evolutionary distance between them. The evolutionary distances between the pre-S/S gene and the base of the tree in patients with low virus loads were greater than those in patients with high virus loads. The mutations in patients with low virus loads were much more frequent than those in patients with high virus loads and were not related to age, irrespective of whether the pre-S/S gene or EnhII/CP/pre-C was considered. CONCLUSIONS: There are HBV quasi species in the sera of AsCs, and the mutations are related to virus load and hepatitis B e antigen seroconversion, irrespective of age.

Adult↗

PubMed2003

[Prokaryocytic expression of the shortened hepatitis B surface antigen and antigenic analysis].

OBJECTIVE: To study the expression of the shortened hepatitis B surface antigen in prokaryocyte and detect the antigenic characters. METHODS: Firstly, the gene fragments coding the 152 and 124 amino acids of the carboxyl terminus of hepatitis B surface antigen (HBsAg) were amplified by polymerase chain reaction (PCR). Secondly, they were cloned to plasmid pBKS+, and the accuracy of those constructions were confirmed by restriction enzyme digestion and DNA sequencing. Then, they were cloned to prokaryocytic expression vector-plasmid pET32a(+). The recombinant plasmids were transfected into E.coli BL21 and induced to express with IPTG. RESULTS: The recombinant plasmids were successfully constructed. In E.coli BL21, the protein was expressed in a fusion fashion and could be recognized by monoclonal antibody against HBsAg with ELISA and Western blot. CONCLUSION: The shortened HBsAg can be expressed in prokaryocyte.

Cloning, Molecular↗

PubMed2003

[Heat shock protein 70-HBsAg complex inducing antigen-specific cytotoxic T lymphocyte immune response].

OBJECTIVE: To explore the possibility of cell-medicated immune response induced with heat shock protein 70 (HSP70)-HBsAg protein complex in vitro. METHODS: HSP70-HBsAg complex was reconstituted in vitro which was injected into mice in order to observe that whether HSP70-HBsAg would stimulate humoral and cellular immune responses. HSP70, HSP70-HBsAg complex and HBsAg were used to activate the dentritic cell (DC) individually, which would initiate homogeneic T lymphocyte to transform to cytotoxic T lymphocyte (CTL). The cytotoxicity of CTL was detected with MTT assay. RESULTS: HSP70-HBsAg complex elicited both humoral and cellular immune responses against HBsAg in mice. Specific CD8+ CTL response was readily induced by HSP70-HBsAg complex and HBsAg, especially the former. CONCLUSIONS: HSP70-HBsAg complex is immunogenic and HSP70 can lead to great efficient CTL response. And HSP70-HBsAg complex may be used as a protein vaccine for immunotherapy for chronic hepatitis B.

Animals↗

PubMed2003

[A study of the characteristics of pre S/S gene mutation of hepatitis B virus (HBV) in mothers and HBV-infected children via mother-to-infant transmission].

OBJECTIVE: To investigate the characteristics of mutations in pre S/S gene of HBV in asymptomatic carrier (AsC) children infected through mother-to-infant transmission and their AsC mothers with different degree of viremia. METHODS: According to the levels of viremia in every pair of mother and child, 15 pairs of child and mother were divided into three groups 5 pairs in each group in this study: group I (both children and mothers had high viremia), group II (children had high and mothers had low viremia) and group III (children had low and mothers had high viremia). pre S/S gene was amplified by PCR and cloned into pGEM-T vector with T-A cloning technique. The recombinant plasmid pGEM- preS/S was confirmed by digestion with restriction enzyme ApaI and SacI. Tow clones were selected to be sequenced in each patient. The mutations of preS/S were compared with HBV DNA consensus sequence of Chongqing. RESULTS: In each group the subtypes of HBV were B/adw2 in 4 pairs and C/adrq+ in one pair. The preS/S clones in patients infected with subtype B/adw2 HBV were analyzed. It was shown that there was no difference among the four high viremic groups or between the two low viremic groups in the number of mutation and the mutational position. However, there was significant difference between the high viremic group and low viremic group. The mutation was not related to age. In the two low viremic groups (the mothers of group II and the children of group III), there were 86-94 mutational positions in 13/16 clones. There were 86 same mutational positions causing 37 amino acid changes in 11/13 clones and 90 same mutational positions causing 38 amino acid changes in 2/13 clones. Most of the changed amino acids were located within T and B cell epitopes of the envelope protein or/and the surrounding regions. Sixty-two mutational positions that resulted in 28 amino acid changes were same in these two mutational sequences. CONCLUSIONS: The mutation of HBV is not associated with the duration of infection. There are many differences of mutation when HBV comes from a same strain in hosts with different degrees of viremia. There are some regular patterns in the mutation of HBV after occurrence of HBeAg seroconversion. The mutation could be related to the escape of the attack of host's immunity.

Adult↗

PubMed2003

[Specific immune responses in Balb/c mice induced by plasmid coexpressing hepatitis B surface antigen and granulocyte-macrophage colony stimulating factor].

OBJECTIVES: To investigate the improvement of specific immune responses induced by plasmid coexpressing hepatitis B surface antigen (HBsAg) and granulocyte-macrophage colony stimulating factor (GM-CSF). METHODS: All Balb/c (H-2d) mice were immunized with pGM-CSF/S, pS/GM-CSF, pS or control plasmids. 4 weeks later, anti-HBs titer and the levels of IL-2, IL-4 and IFN-gamma in the supernatant of splenocytes were detected using enzyme- linked immunosorbent assay (ELISA), and HBsAg-specific cytotoxic T lymphocytes (CTL) activity was measured with a 51Cr release assay, using P815/S transfectants as target cells. RESULTS: The anti-HBs antibody titers in the serum, the levels of IL-2 and IFN-gamma, and the CTL activity in pcDNA3.1-GM-CSF-S immuned mice were higher than those in PcDNA3.1-S immunized mice (F=4.176, P<0.01; F=31.188, P<0.01; F=31.796, P<0.01; F<or=26.891, P<0.01). CONCLUSION: It will improve the specific immune responses induced by HBsAg DNA vaccine after it is binded to the gene of GM-CSF.

Animals↗

PubMed2003

[Establishment of consensus sequence of PreS/S of hepatitis B virus with genotype B/serotype adw2 or genotype C/serotype adrq+ prevailing in Chongqing of China].

OBJECTIVE: To develop consensus sequence of HBV PreS/S with different subtype in Chongqing of China. METHODS: The gene of PreS/S of HBV in 18 AsC was sequenced. The genotype and serotype of HBV were determined. The main HBV strain prevailing in Chongqing was identified to establish its consensus sequence. RESULTS: It was found that 9 strains were genotype B/serotype adw2, 6 were genotype C/serotype adrq+ and 3 were genotype B/serotype ayw1. The consensus sequence of PreS/S of HBV with genotype B/serotype adw2 and genotype C/serotype adrq+ were established. There were 6 nucleotide variants which causing 4 amino acids change between consensus sequence of PreS/S with genotype B/serotype adw2 in Chongqing and in Southeast of China (homology showed 99.5% and 99.0% respectively). There were 13 different sites that caused 4 amino acids change between consensus sequence of PreS/S with genotype C/serotype adrq+ in Chongqing and in Northeast and South of China (homology showed 98.9% and 99.0% respectively). Comparing the two consensus sequence of PreS/S gene of different subtype HBV in Chongqing, there was 95 variants which caused 40 amino acids variants (the homology was 92.1% and 90.0% respectively). CONCLUSION: The consensus sequence of PreS/S of hepatitis B virus with genotype B/serotype adw2 and genotype C/serotype adrq+ prevailing in Chongqing was established.

Adolescent↗

PubMed2003

Relationship between the different replication status of HBV and mutations in the core promoter in mothers and their children infected via mother-to-infant transmission.

OBJECTIVE: To study the relationship between the different replication status of hepatitis B virus (HBV) and mutations in the core promoter (CP) in mother and her child infected by mother-to-infant transmission. METHODS: The core promoter was amplified by PCR and cloned into pGEM-T vector with the T-A cloning technique. The recombinant plasmid pGEM-CP was confirmed by digestion with restriction enzyme Apa I and Sac I. Two clones were selected to be sequenced in each patient. RESULTS: Every pair of mother and child had same serotype and genotype and the homology of nucleotides encoding "a" determinant was 98%-100%. The number of mutations in the core promoter of patients with a high replication status was less than that in those with a low replication status. Mutations were mainly distributed in basia core promoter (BCP) and the inhibitor region of Kunitz-type serine protease. This difference was not associated with mother or child. CONCLUSION: The different replication status of HBV is caused by mutations in the core promoter in mother and child infected by mother-to-infant transmission and appears to be not associated with the status of development of the infection.

Adult↗

PubMed2003

[Secretion expression of Mt. heat shock protein 70 in Pichia pastoris and identification of the protein].

To obtain the expression of Mycobacterium tuberculosis heat shock protein 70 in methylotropic yeast. The expression vector pPIC9K-hsp70 was constructed, linearized and introduced into Pichia pastoris GS115 by electroporation. The result protein was secreted into the supernatant induced by 0.5% methanol at 30 degrees C and purified by centrifugation, ultrafiltration and ATP-agarose. The recombinant Hsp70 was identified by SDS-PAGE, Western blot, mice experiment and effect on the immature DC. The SDS-PAGE and Western blot analysis showed that the apparent molecular weight of expressed Hsp70 was about 70 kD and the expressed protein could specifically react with anti-Mt. Hsp70 IgG. And mice immunization indicated the expressed hsp70 had immunogenicity. Hsp70 could induce DC maturation and release Th1 cytokine. The secreted 70 kD protein was about 120 mg/L which accounted for more than 30% of the total supernatant protein and was purified to electrophoretic purity. The Hsp70, which had the biological activity, is successfully secretorily expressed in the Pichia pastoris GS115.

Animals↗

PubMed2002

[Relationship between the different replication status of HBV and mutations in core promoter in mother and children infected by mother-to-infant transmission].

OBJECTIVE: To understand the relationship between the different replication status of HBV and mutations in core promoter in mother and child infected by mother-to-infant transmission. METHODS: Core promoter was amplified by PCR and cloned into pGEM-T vector with T-A cloning technique. The recombinant plasmid pGEM-PreS/S was confirmed by digestion with restriction enzyme Apa I and Sac I. Two clones were selected to sequence each patient. RESULTS: Every pair of mother and child had same serotype and genotype and the homology of nucleotides encoding "a" determinant was 98 to 100%. The number of mutations in core promoter in patients with high replication status was more than that of low replication status. Mutations were distributed in BCP and Kunitz-type serine protease inhibitor region mainly. This difference was not associated with mother or child. CONCLUSIONS: The different replication status of HBV is caused by mutations in core promoter in mother and child infected by mother-to-infant transmission and seems not to be associated with the development status.

Child↗

PubMed2002

High-resolution imaging of living retina through optic adaptive retinal imaging system.

PURPOSE: To evaluate the possibility as well as the usage of adaptive optics in high-resolution retinal imaging. METHODS: From March to November 2001, the fundus of 25 adults were checked by using Optic Adaptive Retinal Imaging System (OAS). The age of the subjects varied from 18 - 48 years. All had normal visual acuity from 0.9 to 1.0. No abnormality was found in the ocular examination, and their medical as well as ocular history was unremarkable. RESULTS: High-resolution images of the retinal cells, photoreceptor and bipolar cell, were analysed. In these images, the cells are clearly resolved. The density of the photoreceptor at area 1.5 degree from the foveloa is around 40 000 - 50 000/mm2. At area 3 degree, it drops to less than 30 000/mm2. CONCLUSION: Optic Adaptive Retinal Imaging System (AOS) is able to get high-resolution image of retinal cells in living human eyes. It may be widely used in ophthalmology experimentally and clinically.

Adolescent↗