The effect of population density on the phenotype, metabolic and immunological adaptations in the cuticle of Spodoptera litura larvae.

Background: Species that experience outbreaks and those that display density-dependent phase polymorphism demonstrate density-dependent prophylaxis (DDP) by increasing their immune investment in response to increasing densities. Despite this phenomenon, the mechanisms of DDP remain largely unexplored.

Results: Here, we showed that Spodoptera litura exhibited heightened cuticular melanization and enhanced cuticular immune responses when reared at higher population density.

Production of a new tetravalent vaccine targeting fimbriae and enterotoxin of enterotoxigenic .

Enterotoxigenic (ETEC) is an important type of pathogenic bacteria that causes diarrhea in pigs. The objective of this study was to prepare a novel tetravalent vaccine to effectively prevent piglet diarrhea caused by In order to realize the production of tetravalent inactivated vaccine, the biological characteristics, stability, preservation conditions, and safety of the recombinant strain BL21(DE3) (pXKKSL4) were studied, and the vaccine efficacy and minimum immune dose were measured. The results indicated that the biological characteristics, target protein expression, and immunogenicity of the 1st to 10th generations of the strain were stable.

Development of a new candidate vaccine against piglet diarrhea caused by .

Enterotoxigenic (ETEC) is an important type of pathogenic bacteria that causes diarrhea in humans and young livestock. The pathogen has a high morbidity and mortality rate, resulting in significant economic losses in the pig industry. To effectively prevent piglet diarrhea, we developed a new tetravalent genetically engineered vaccine that specifically targets ETEC.

NPC1L1 Plays a Novel Role in Nonalcoholic Fatty Liver Disease.

Niemann-Pick C1-Like 1 (NPC1L1) is a key protein in the transport of cholesterol, which exists in the brush marginal membrane of the intestinal epithelial cells and the timid duct membrane of the liver. It affects cholesterol absorption and plasma low-density lipoprotein levels. Cholesterol is both an important component of the cell membrane and a precursor of bile acid and steroid hormone synthesis.

Preparation of novel trivalent vaccine against enterotoxigenic Escherichia coli for preventing newborn piglet diarrhea.

Objective: To develop a trivalent genetically engineered inactivated Escherichia coli vaccine (K88ac-3STa-LTB) that neutralizes the STa toxin by targeting fimbriae and entertoxins for the treatment of enterotoxigenic E coli.

Animals: 18- to 22-g mice, rabbits, pregnant sows.

Procedures: Using PCR, the K88ac gene and LTB gene were cloned separately from the template C83902 plasmid.

Molecular structure and function of the carboxy-terminus of the alpha-toxin from Clostridium perfringens type A.

In order to interpret the molecular structure and biological characteristics of Clostridium perfringens alpha-toxin (CPA), the CPA251-370 gene was cloned and the 120 amino acid carboxy terminal of CPA (CPA251-370) was obtained. The secondary and three-dimensional (3D) structures of CPA251-370 were predicted. The secondary structure of CPA251-370 consisted primarily of 35.

Study of the Structure and Biological Activity of the Amino-Terminus of the α-Toxin from Clostridium welchii Type A.

To explore the biological activity of Clostridium welchii α-toxin (CPA), the Asp56 residue of CPA was mutated to glycine (CPA D56G) by site-directed mutagenesis, and the 250 amino acid amino-terminal phospholipase C (PLC)-containing domain of CPA (PLC1-250) was isolated. The secondary and three-dimensional (3D) structures of CPA D56G and PLC1-250 were predicted, and the results showed that the secondary structures of CPA D56G and PLC1-250 were composed of α-helices and random coils. The 3D structures of CPA D56G and PLC1-250 were similar to the 3D structures of CPA.

CDC42-Interacting Protein 4 Gene Is Down Trans-Regulated by HBV DNA polymerase Trans Activated Protein 1.

Background: Hepatitis B Virus (HBV) DNA polymerase transactivated protein 1 (HBVDNAPTP1) is a novel protein transactivated by HBV DNA polymerase, screened by suppression subtractive hybridization technique (GenBank accession no: AY450389). The biological function of HBVDNAPTP1 was investigated in this study.

Methods: We constructed a vector pcDNA3.

Construction of multiple recombinant SLA-I proteins by linking heavy chains and light chains in vitro and analyzing their secondary and 3-dimensional structures.

Six breeds of swine were used to study the structure of swine leukocyte antigen class I (SLA-I). SLA-I complexes were produced by linking SLA-2 genes and β(2)m genes via a linker encoding a 15 amino acid glycine-rich sequence, (G4S)3, using splicing overlap extension (SOE)-PCR in vitro. The six recombinant SLA-2-linker-β(2)m genes were each inserted into p2X vectors and their expression induced in Escherichia coli TB1.

[Analyzing secondary structure of beta2 microglobulin in Escherichia coli with circular dichroism spectrum].

Objective: In order to study the structure and function of beta2 microglobulin (beta2 m).

Methods: We sub-cloned the mature peptide of beta2 m into the p2X plasmid and transformed them to Escherichia coli TB1. The recombinant bacterium was induced to be expressed and the expressed fusion protein was detected by SDS-PAGE and western blot.

Secondary structure and 3D homology modeling of swine leukocyte antigen class 2 (SLA-2) molecules.

No information to date is available to elucidate the structure of swine leukocyte antigen class I (SLA-I) molecule which is comprised by a heavy chain of SLA-I non-covalently associated with a light chain, beta(2)-microglobulin (beta(2)m) proteins. Presently, one of SLA-I gene SLA-2 and beta(2)m gene were expressed as soluble maltose binding proteins (MBP-proteins) in a pMAL-p2X/Escherichia coli TB1 system and identified by western blotting with anti-MBP polyclonal antibodies. The expressed proteins MBP-SLA-2 and MBP-beta(2)m were purified on amylose affinity columns followed by DEAE-Sepharose.

[Expression of alpha-toxin gene of Clostridium perfringens type A and its primary immunological protective function].

Alpha-toxin gene was amplified from chromosomal DNA of Clostridium perfringens type A by polymerase chain reaction (PCR). PCR product was inserted into vector pGEM-T directly. The cloned recombinant plasmid pXCPA02 possesses positive nucleotide sequence of alpha-toxin.

[Fusion of betal-toxin gene and beta2-toxin gene from Clostridium perfringens type C].

Betal-toxin and beta2-toxin genes from chromosomal DNA of Clostridium perfringens type C were amplified by PCR, PCR products were cleaved with restriction endonucleases and recovered. The recombinant plasmid pETXB1-2 containing beta1-beta2 fusion genes was constructed by recombinant technique and then transformed into Escherichia coli BL21 (DE3). The beta1-beta2 fusion proteins were expressed in recombinant strain BL21 (DE3) (pETXB1-2), and the expression level of the beta1-beta2 fusion proteins was about 15.

[Construction of recombinant strain expressing enterotoxigenic Escherichia coli K88ac-ST1-LTB fusion protein].

K88ac genes, heat-stable enterotoxin I (ST1) mutant genes and heat-labile enterotoxin B subunit (LTB) genes from plasmids of Escherichia coli C83902 were amplified by PCR. The recombinant expression plasmid pXKST3LT5 containing K88ac-ST1-LTB fusion gene was constructed by recombinant DNA technique and then transformed into Escherichia coli BL21(DE3). The K88ac-ST1-LTB fusion protein was highly expressed in recombinant strain BL21 (DE3)(pXKST3LT5) and the expression level of the K88ac-ST1-LTB fusion protein was about 75.