Endotoxins are common exogenous pyrogens. Excessive endotoxins in medical devices and injections can lead to serious consequences such as sepsis, septic shock, and even death. Therefore, endotoxin detection plays a crucial role in medical, pharmaceutical, and food sectors. The wide application of Limulus amebocyte lysate (LAL) has led to a sharp decline in the number of horseshoe crabs. Moreover, the LAL assay has limitations such as interbatch variations and difficulty in quantification. The recombinant factor C (rFC) assay is stable between batches, highly sensitive, and capable of quantitation, and thus it can be used as an alternative for the LAL assay. However, the high cost and complex procedures involved in producing recombinant factor C have limited the widespread application of this method. In order to simplify the preparation and reduce the production cost of recombinant factor C, this study focuses on the production of recombinant factor C based on the baculovirus expression system. Multiple measures such as a high-yield and anti-apoptotic vector qBac-IIIG, the optimal signal peptide, and the optimized codon were used to reach the goal of endotoxin detection with cell supernatant. This method simplifies the steps of protein purification. The sensitivity of the supernatant reached 0.05 EU/mL in a 1-L fermentation system, and 500 000 detecting reactions can be supported per liter of fermentation broth. This study increases the yield and activity of recombinant factor C, simplifies the procedures of protein purification, and reduces the cost, laying a foundation for the promotion and application of recombinant factor C in endotoxin detection.
Animals ; Recombinant Proteins/genetics* ; Horseshoe Crabs/chemistry* ; Baculoviridae/metabolism* ; Endotoxins/analysis* ; Protein C/biosynthesis* ; Genetic Vectors/genetics* ; Arthropod Proteins/genetics* ; Enzyme Precursors ; Serine Endopeptidases

This study aimed to obtain a recombinant human-source collagen for industrialization. First, based on the Gly-X-Y sequence of human type I collagen, we optimized the hydrophilic Gly-X-Y collagen peptide, designed the human collagen amino acid sequence and the corresponding nucleotide sequence. Next, the expression vector pPIC9K-COL was constructed via endonuclease digestion technology. We obtained an engineering strain of human-source collagen by electrotransforming Pichia pastoris, and then it was fermented, purified and identified. As a result, the expression level reached 4.5 g/L and the purity was over 95%. After amino acid N-terminal sequencing, molecular weight analysis, amino acid analysis and collagenase degradation test, we confirmed that the obtained collagen was consistent with designed primary structure of human-source collagen. After freeze-drying, we analyzed the collagen by scanning electron microscope and cell cytotoxicity, confirming that the collagen has porous fiber reticular structure and superior cytocompatibility. This indicates that human-source collagen has potential to be applied as biomedical material. In conclusion, we successfully obtained the expected human-source collagen and laid a foundation to its further application.
Amino Acid Sequence ; Biocompatible Materials ; Collagen ; analysis ; Freeze Drying ; Humans ; Pichia ; Recombinant Proteins

Conventional immunotherapy (IT) for optimal control of respiratory and food allergies has been fraught with concerns of efficacy, safety, and tolerability. The development of adjuvants to conventional IT has potentially increased the effectiveness and safety of allergen IT, which may translate into improved clinical outcomes and sustained unresponsiveness even after cessation of therapy. Novel strategies incorporating the successful use of adjuvants such as allergoids, immunostimulatory DNA sequences, monoclonal antibodies, carriers, recombinant proteins, and probiotics have now been described in clinical and murine studies. Future approaches may include fungal compounds, parasitic molecules, vitamin D, and traditional Chinese herbs. More robust comparative clinical trials are needed to evaluate the safety, clinical efficacy, and cost effectiveness of various adjuvants in order to determine ideal candidates in disease-specific and allergen-specific models. Other suggested approaches to further optimize outcomes of IT include early introduction of IT during an optimal window period. Alternative routes of administration of IT to optimize delivery and yet minimize potential side effects require further evaluation for safety and efficacy before they can be recommended.
Antibodies, Monoclonal ; Asian Continental Ancestry Group ; Base Sequence ; Cost-Benefit Analysis ; Food Hypersensitivity ; Humans ; Immunization ; Immunotherapy ; Probiotics ; Recombinant Proteins ; Treatment Outcome ; Vitamin D

Objective: To elucidate the possible role of human lysozyme-like protein 4 (LYZL4) in fertilization and characterize its enzymatic properties. METHODS: The localization of LYZL4 in human spermatozoa was investigated by immunofluorescence staining, the sources of LYZL4 on the sperm surface examined by RT-PCR, and the role of LYZL4 in fertilization assessed by the zona-free hamster egg penetration test. The recombinant plasmid pPIC9K-LYZL4 was constructed and its expression induced with methanol after transformed into competent Pichia pastoris GS115. The recombinant LYZL4 protein (rLYZL4) was purified from the fermentation supernatant and subsequently identified by Western blot. The hyaluronan binding ability of rLYZL4 was determined by ELISA and the muramidase activity, hyaluronidase activity, and free radical scavenging ability examined by spectrophotometric methods. RESULTS: Immunodetection with a specific antiserum localized LYZL4 on the acrosomal membrane of mature spermatozoa, which was exclusively secreted from the testis and epididymis as shown by RT-PCR. Immunoneutralization of LYZL4 significantly decreased the number of human spermatozoa bound to zona-free hamster eggs in a dose-dependent manner in vitro. The recombinant protein was expressed successfully by the P. pastoris strain GS115. Purified rLYZL4 exhibited a potent hyaluronan binding ability and a strong free radical scavenging ability but no muramidase or hyaluronidase activity. CONCLUSIONS LYZL4 secreted from the testis and epididymis is localized on the acrosomal membrane of mature spermatozoa and plays a role in sperm-egg binding as well as in binding hyaluronan and scavenging free radicals, which suggests that it might be a multi-functional molecule contributive to sperm protection and sperm-egg binding.
Acrosome ; enzymology ; Animals ; Blotting, Western ; Cricetinae ; Enzyme-Linked Immunosorbent Assay ; Epididymis ; Female ; Fertilization ; physiology ; Free Radical Scavengers ; metabolism ; Humans ; Hyaluronic Acid ; metabolism ; Male ; Muramidase ; analysis ; physiology ; Pichia ; Plasmids ; metabolism ; Recombinant Proteins ; analysis ; metabolism ; Sperm-Ovum Interactions ; physiology ; Spermatozoa ; enzymology ; Testis

OBJECTIVETo observe the effects of recombinant fusion protein interleukin (IL)-18 on the expression of immune-inflammatory factors in the mice infected with Staphylococcus aureus (SA), and to investigate the mechanism of action of IL-18 in defense of SA infection in vivo.

METHODSA total of 40 specific pathogen-free female BLAB/c mice were randomly divided into four groups: control, SA infection, immunized, and intervention. A mouse model of SA infection was established by nasal inoculation with SA liquid. The immunized group and the intervention group were intranasally given IL-18 before SA modeling, and then the SA infection group and the intervention group received the nasal inoculation with SA liquid; the control group was treated with phosphate buffered saline instead. The levels of IL-4, interferon (IFN)-γ, tumor necrosis factor (TNF), granulocyte colony-stimulating factor (G-CSF), IgM in the serum and bronchoalveolar lavage fluid (BALF) of mice were measured by enzyme-linked immunosorbent assay. The expression of macrophage inflammatory protein (MIP)-1α mRNA and MIP-2β mRNA in the lung tissue of mice were determined by real-time fluorescent quantitative PCR.

RESULTSCompared with the control group, the SA infection group and the immunized group had significantly higher levels of IL-4, G-CSF, and IgM in the serum and BALF and expression of MIP-1α mRNA and MIP-2β mRNA in the lung tissue (P<0.05); the SA infection group had a significantly lower level of IFN-γ and a significantly higher level of TNF in the serum and BALF (P<0.05); the immunized group had a significantly higher level of IFN-γ in the serum and BALF (P<0.05). Compared with the SA infection group, the intervention group had significantly higher levels of IL-4, IFN-γ, G-CSF, and IgM in the serum and BALF and expression of MIP-1α mRNA in the lung tissue. In contrast, the intervention group showed a significantly lower level of TNF in the serum and BALF and expression of MIP-2β mRNA in the lung tissue (P<0.05). All the above indicators in the intervention group were significantly higher than those in the control group (P<0.05), except the serum level of IFN-γ.

CONCLUSIONSIn the mice infected with SA, the recombinant fusion protein IL-18 by mucosal immunity can affect inflammatory factors in the serum and BALF and the expression of MIP-1α mRNA and MIP-2β mRNA in the lung tissue to promote the anti-infective immune response and enhance the ability to clear pathogens.

Animals ; Chemokine CCL3 ; analysis ; Female ; Granulocyte Colony-Stimulating Factor ; blood ; Interferon-gamma ; blood ; Interleukin-18 ; therapeutic use ; Interleukin-4 ; blood ; Mice ; Mice, Inbred BALB C ; Recombinant Fusion Proteins ; pharmacology ; therapeutic use ; Staphylococcal Infections ; drug therapy ; immunology

Objective: To prepare a polyclonal antibody against human lysozyme-like protein 4 (LYZL4) expressed in the prokaryotic system and identify the distribution of LYZL4 in the testis. METHODS: The full-length cDNA of LYZL4 was cloned into the pET32a plasmid and the expression of the recombinant LYZL4 (rLYZL4) was induced by IPTG. The rLYZL4 was purified by Ni-NTA and chitin affinity chromatography respectively and its bactericidal activity was observed by bilayer agar plate diffusion assay. The purified rLYZL4 was used as an immunogen to generate the polyclonal antibody, followed by examination of the antibody titer by ELISA and its specificity by Western blot. The distribution of LYZL4 in human tissue, sperm and seminal plasma was identified and its subcellular localization in the testis was determined by immunohistochemistry. RESULTS: rLYZL4 was expressed efficiently in the prokaryotic system and exhibited no bacteriolytic activity against M. lysodeikticus and E. coli. The anti-rLYZL4 polyclonal antibody could bind the recombinant protein with a high sensitivity and specificity. LYZL4 was identified in the testis, epididymis and sperm protein extracts and localized in the acrosomal region of round and elongating spermatids. CONCLUSIONS An anti-rLYZL4 polyclonal antibody was successfully prepared using the prokaryotic expression system. LYZL4 was detected in the acrosomal region of round and elongating spermatids, suggesting an association with the structure and function of the acrosome.
Acrosome ; immunology ; Animals ; Antibodies ; analysis ; Blotting, Western ; DNA, Complementary ; Enzyme-Linked Immunosorbent Assay ; Epididymis ; immunology ; Escherichia coli ; Humans ; Immunohistochemistry ; Male ; Muramidase ; genetics ; immunology ; Plasmids ; Recombinant Proteins ; genetics ; Semen ; immunology ; Spermatozoa ; immunology ; Testis ; immunology

Salvia miltiorrhiza is a medicinal plant widely used in the treatment of cardiovascular and cerebrovascular diseases. Hydrophilic phenolic acids, including rosmarinic acid (RA) and lithospermic acid B (LAB), are its primary medicinal ingredients. However, the biosynthetic pathway of RA and LAB in S. miltiorrhiza is still poorly understood. In the present study, we accomplished the isolation and characterization of a novel S. miltiorrhiza Hydroxyphenylpyruvate reductase (HPPR) gene, SmHPPR, which plays an important role in the biosynthesis of RA. SmHPPR contained a putative catalytic domain and a NAD(P)H-binding motif. The recombinant SmHPPR enzyme exhibited high HPPR activity, converting 4-hydroxyphenylpyruvic acid (pHPP) to 4-hydroxyphenyllactic acid (pHPL), and exhibited the highest affinity for substrate 4-hydroxyphenylpyruvate. SmHPPR expression could be induced by various treatments, including SA, GA, MeJA and Ag, and the changes in SmHPPR activity were correlated well with hydrophilic phenolic acid accumulation. SmHPPR was localized in cytoplasm, most likely close to the cytosolic NADPH-dependent hydroxypyruvate reductase active in photorespiration. In addition, the transgenic S. miltiorrhiza hairy roots overexpressing SmHPPR exhibited up to 10-fold increases in the products of hydrophilic phenolic acid pathway. In conclusion, our findings provide a new insight into the synthesis of active pharmaceutical compounds at molecular level.
Amino Acid Sequence ; Benzofurans ; Biosynthetic Pathways ; genetics ; Cinnamates ; Depsides ; Gene Expression Regulation, Plant ; genetics ; Oxidoreductases ; genetics ; Phenylpropionates ; metabolism ; Phenylpyruvic Acids ; metabolism ; Phylogeny ; Plant Proteins ; genetics ; metabolism ; Plant Roots ; chemistry ; enzymology ; genetics ; metabolism ; Plants, Genetically Modified ; Recombinant Proteins ; analysis ; biosynthesis ; Salvia miltiorrhiza ; chemistry ; enzymology ; genetics ; metabolism ; Sequence Alignment

OBJECTIVEIn this study, we evaluated the diagnostic efficiency of six recombinant proteins for the serodiagnosis of Lyme borreliosis (LB) and screened out the appropriate antigens to support the production of a Chinese clinical ELISA (enzyme-linked immunosorbent assay) kit for LB.

METHODSSix recombinant antigens, Fla B.g, OspC B.a, OspC B.g, P39 B.g, P83 B.g, and VlsE B.a, were used for ELISA to detect serum antibodies in LB, syphilis, and healthy controls. The ELISA results were used to generate receiver operating characteristic (ROC) curves, and the sensitivity and specificity of each protein was evaluated. All recombinant proteins were evaluated and screened by using logistic regression models.

RESULTSTwo IgG (VlsE and OspC B.g) and two IgM (OspC B.g and OspC B.a) antigens were left by the logistic regression model screened. VlsE had the highest specificity for syphilis samples in the IgG test (87.7%, P<0.05). OspC B.g had the highest diagnostic value in the IgM test (AUC=0.871). Interactive effects between OspC B.a and Fla B.g could reduce the specificity of the ELISA.

CONCLUSIONThree recombinant antigens, OspC B.g, OspC B.a, and VlsE B.a, were useful for ELISAs of LB. Additionally, the interaction between OspC B.a and Fla B.g should be examined in future research.

Antigens, Bacterial ; blood ; Bacterial Proteins ; analysis ; China ; Enzyme-Linked Immunosorbent Assay ; veterinary ; Lyme Disease ; diagnosis ; Recombinant Proteins ; analysis ; Sensitivity and Specificity ; Serologic Tests ; veterinary

OBJECTIVETo investigate the efficacy and safety of different doses of recombinant human growth hormone (rhGH) in the treatment of short stature in children born small for gestational age (SGA).

METHODSA total of 37 children with short stature born SGA were enrolled, and based on the dose of rhGH treatment, they were divided into low-dose rhGH group (0.1-0.15 IU/kg daily) and high-dose rhGH group (0.16-0.2 IU/kg daily). The changes in height standard deviation score (ΔHtSDS), height velocity (HV), serum levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3), and fasting blood glucose at 3, 6, 9, 12, and 24 months after treatment were compared between the two groups.

RESULTSΔHtSDS and HV both increased after the treatment with high- and low-dose rhGH, but ΔHtSDS and HV in the high-dose rhGH group were significantly higher than in the low-dose rhGH group 9, 12 and 24 months after treatment (P<0.05). Both high- and low-dose rhGH treatment increased serum levels of IGF-1 and IGFBP-3. Serum levels of IGF-1 and IGFBP-3 were positively correlated with HtSDS in both groups. One child each in the high- and low-dose rhGH groups experienced transient slight increase in fasting blood glucose (6.1 mmol/L). There were no cases of abnormal thyroid function.

CONCLUSIONSrhGH has good efficacy in the treatment of short stature in children born SGA, with few adverse events, and high-dose rhGH has some advantages over low-dose rhGH.

Body Height ; Child ; Child, Preschool ; Female ; Growth Disorders ; blood ; drug therapy ; Human Growth Hormone ; therapeutic use ; Humans ; Infant, Small for Gestational Age ; Insulin-Like Growth Factor Binding Protein 3 ; blood ; Insulin-Like Growth Factor I ; analysis ; Male ; Recombinant Proteins ; therapeutic use

Ethyl carbamate (EC) as a potential carcinogen commonly exists in traditional fermented foods. It is important eliminate urea that is the precursors of EC in many fermented foods, including Chinese Rice wine. On the basis of achieving high-level overexpression of food-grade ethanol-resistant acid urease, we studied the hydrolysis of urea and EC with the recombinant acid urease. Recombinant acid urease showed degraded urea in both the simulated system with ethanol and Chinese Rice wine (60 mg/L of urea was completely degraded within 25 h), indicating that the recombinant enzyme is suitable for the elimination of urea in Chinese Rice wine. Although recombinant acid urease also has degradation catalytic activity on EC, no obvious degradation of EC was observed. Further investigation results showed that the Km value for urea and EC of the recombinant acid urease was 0.7147 mmol/L and 41.32 mmol/L, respectively. The results provided theoretical foundation for realizing simultaneous degradation of urea and EC.
Oryza ; Recombinant Proteins ; metabolism ; Urea ; chemistry ; Urease ; metabolism ; Urethane ; chemistry ; Wine ; analysis