Biology subjects

chen, c.

Publications and source records attributed to chen, c..

6 recordsLinked to original sources

bioRxiv2022

FIB-SEM analysis on three-dimensional structures of growing organelles in wild Chlorella pyrenoidosa cells

To clarify dynamic changes of organelle microstructures in Chlorella pyrenoidosa cells during photosynthetic growth with CO2 fixation, three-dimensional organelle microstructures in three growth periods of meristem, elongation and maturity were quantitatively determined and comprehensively reconstructed with focused ion beam scanning electron microscopy (FIB-SEM). The single round-pancake mitochondria in each cell split into a dumbbell and then into a circular ring, while barycenter distance of mitochondria to chloroplast and nucleus was reduced to 45.5% and 88.3% to strengthen energy transfer, respectively. The single pyrenoid consisting of a large part and another small part in each chloroplast gradually developed to a mature state in which the two parts were nearly equal in size. The nucleolus progressively became larger with euchromatin replication. The number of starch grains gradually increased, but average grain volume remained nearly unchanged.

cell biology↗

bioRxiv2021

Brucella outer membrane proteins to control maturation and antigen presentation of mouse dendritic cells

Brucellosis is a highly contagious zoonotic disease, which seriously endangers animal husbandry in China. Bone marrow-derived dendritic cells (DCs) are full-time antigen presenting cells (APC) that play an important role in the interaction between pathogens and host immunity. DCs were stimulated with Brucella major outer membrane proteins (OMPs: OMP10, OMP19, OMP25, BP26 and OMP31) and Brucella mutants ({Delta} omp10, {Delta} omp19, {Delta} omp25, {Delta} bp26, {Delta} omp31) to examine effects on DC maturity and antigen presentation. Brucella OMP10, OMP19 and BP26; Brucella mutants {Delta} omp10, {Delta} omp19, {Delta} omp25, {Delta} bp26, {Delta} omp31 and Brucella RB51 induced DC maturation and antigen presentation efficiency in mice, activated proliferation of T lymphocytes, and decreased apoptosis, which helped the host recognize antigens and eliminate pathogens. However, B. abortus 2308 evaded the host immune function and established chronic infection by maintaining a balance between intracellular replication and inducing apoptosis, thus reducing DC maturation and antigen presentation to T cells. Toll-like receptor (TLR) -mediated signaling pathways were involved in the DC maturation and antigen presentation induced by Brucella OMPs. These results enhance understanding of Brucella pathogenesis and the host protective immune response mechanism and lay the foundation for the rational design of Brucella vaccines.

microbiology↗

bioRxiv2021

A CTLA-4 nanobody improves the immunity of mice against challenges with Staphylococcus aureus and Streptococcus agalactiae

Cytotoxic T lymphocyte associated antigen 4 (CTLA-4), also known as CD152, is a transmembrane receptor and leukocyte differentiation antigen on T cells that participates in the negative regulation of immune responses. CTLA-4 Ig can effectively and specifically inhibit cellular and humoral immune responses in vivo and in vitro, and is therefore, considered to be a promising new immunosuppressive antibody. In this study, we investigated the role of CTLA-4 nanobody in immunity. We purified recombinant CTLA-4 protein and constructed a phage display nanobody library. After screening the library, we obtained a nanobody with high affinity for the CTLA-4 protein. The nanobody was expressed and purified and the specific high-affinity for CTLA-4 confirmed by enzyme-linked immunosorbent assay. The nanobody was shown to enhance the activity and nitric oxide (NO) production of bone marrow derived dendritic cells (DCs) as well as their ability to capture foot-and-mouth disease virus (FMDV). The CTLA-4 nanobody also improved the immunity of animals after challenge with Staphylococcus aureus and Streptococcus agalactiae, thus indicating the potential of the CTLA-4 nanobody to improve cellular immunity and enhance immune responses.

cell biology↗

bioRxiv2020

A meta-analysis and experiment assessing phage-based FMDV vaccine

Foot-and-mouth disease (FMD) is a pathological disease caused by the foot- and-mouth disease virus (FMDV), which mainly affects cloven-hoofed animals. This study was conducted to a meta-analysis and experiment on the effect of bacteriophages used in the development of FMDV vaccines. A systematic search was conducted for the collection of the protection effect for the phage-based FMDV vaccine using sensitive search strategies. The extracted data were analyzed using Rev-Man 5.4 software. This experiment used the T7 phage to express the capsid protein VP1 of the OHM-02 strain, and the recombinant VP1 phage was termed OHM-T7. Antibodies and cytokines levels were assessed after immunizing BALB/C mice with OHM-T7. The results showed that a total of 115 articles were retrieved, and 4 of them met the inclusion criteria. There was no heterogeneity with I2 = 0%, 20% or 43%. We used a fixed-effect model for meta-analysis, and the results showed a protective effect on FMDV between the phage group and control group (P<0.01) and between FMDV group and control group (P<0.01). Furthermore, when the phage group was compared to the FMDV group, there was also no significant difference (P>0.05). After successfully obtained the ohm-t7 strain and immunized the mice, it could induce high levels of IFN-{gamma} levels in mice with little effect on IL-4 levels. OHM-T7 could be used to detect antibodies produced by mice immunized with different FMDV antigens and produce high levels of anti-FMD antibodies. In summary, these results showed the potential of phage-based FMDV vaccines in FMDV prevention.

immunology↗

bioRxiv2020

A Systematic Review and Meta-analysis of the Protective Effect of FMDV VP1 on Animals

The FMDV VP1 protein has different structures which could decrease or increase the immune response. We undertook a meta-analysis to evaluate the protective effect of VP1 on the FMDV. A systematic search of the PubMed, Embase, CNKI and Wan fang DATA was conducted up to April 2020. Experimental studies involving the VP1 protection effect on FMDV were included. Extracted data were analyzed using Rev-Man 5.3 software. Chi-square tests were used to analyze the heterogeneity among the documents. The fixed-effect model was used for meta-analysis to find the combined effect value and 95% confidence interval. Sensitivity analysis was performed on the differences in the combined values of model effects, and the inverted funnel chart method was used to assess the publication bias of the included literature. A total of 12 articles were included for meta-analysis. The results of showed that VP1 had a protective effect on FMDV [MH = -0.66, 95% CI = (-0.75, -0.56), P < 0.00001]. Sensitivity analysis showed that the results were robust. The funnel graph method showed that the published literature had a small publication bias and met the requirements of this study. It is necessary to study the epitopes of VP1 to produce new vaccines. VP1 could protect animals from FMDV attacks. It is necessary to study the VP1 protein and its epitopes and use it as a new vaccine and diagnostic product.

immunology↗

bioRxiv2020

Abortion and various associated risk factors in dairy cow and sheep in Ili, China

We studied livestock abortion and various associated risk factors in the Ili region of northwest China. Livestock abortion prevalence was estimated and correlated with infections (Brucellosis, Salmonellosis, Mycoplasma and Chlamydia seropositivity) and management (farming type and contact with other herds/flocks) risk factors. The prevalence of cow and sheep abortion induced by Brucella was 76.8% (P<0.0001) and 84.1% (P<0.0001), and Mycoplasma caused an estimated 15.5% (P=0.025) and 17.6% (P<0.001) abortions, respectively. Abortion-related risk factors included mixed farming (cow P=0.001, sheep P<0.001), contact with other flocks (cow P=0.007, sheep P=0.003), brucellosis positivity (cow P<0.001, sheep P<0.001) and Mycoplasma positivity (cow P=0.031, sheep P<0.001). A total of 2996 serum samples (1402 cow, 1594 sheep) were identified by RBPT (Rose Bengal Plate Test), and they showed the seroprevalence of brucellosis in X county was cow 7.1%, sheep 9.1%; in H county was cow 11.7%, sheep 10.7%; and in Q county was cow 4.2%, sheep 9.1%. The seroprevalence of Mycoplasma in X county was cow 3.4%, sheep 7.9%; in H county was cow 5.3%, sheep 9.9%; and in Q county was cow 2.1%, sheep 4.3%. A total of 54 samples, including aborted cow (22), sheep (30) fetuses and milk samples (2), were identified as Brucella melitensis (B. melitensis) positive. A total of 38 Brucella were isolated from 16 aborted cow, 20 sheep fetuses and 2 milk samples. All of these isolates were identified, and confirmed, as B. melitensis. A phylogenetic tree showed that the Brucella isolates closely matched the B. melitensis biovar 3 isolated in Inner Mongolia, China, and B. melitensis isolated from Norway and India. These results suggest that B. melitensis biovar 3 is the main pathogen responsible for cow and sheep abortion and also pose a human health risk. Additionally, livestock reproduction can also be influenced by Mycoplasma infection and managerial factors (farming type and contact with other herds/flocks), especially in remote areas.View Full Text

zoology↗