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BACKGROUND:Frog active peptides have rich activities,such as antibacterial and anti-tumor,and are expected to solve the problem of antibiotic resistance. OBJECTIVE:The active peptide QUB2984 was discovered in the skin secretions of Agalychnis callidryas.Its structure and properties were simulated by bioinformatics.The peptide was synthesized,purified,and identified and its biological functions were investigated. METHODS:Agalychnis callidryas skin secretions were collected by electrostimulation.The sequence of QUB2984 was obtained through constructing a cDNA library with isolated mRNA.BLAST was used for peptide sequence alignment.Besides that,Iterative Threading ASSEmbly Refinement(I-TASSER)and HeliQuest tools were used for protein secondary structure simulation.It was synthesized by solid-phase peptide synthesis,purified by reverse-phase high-performance liquid chromatography,and structurally confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.The purified peptide was used to evaluate its biological activity.Its antibacterial effect was evaluated by the minimum inhibitory concentration method.Its cytotoxic effect was detected by MTT assay.Its safety was investigated by a hemolysis test. RESULTS AND CONCLUSION:(1)Peptide QUB2984 had basically α-spiral structure,with a relatively intact hydrophobic surface,and a certain destructive ability to biofilm.The third amino acid position of QUB2984 was composed of W and had a G-X-G structure.(2)The minimum inhibitory concentration of QUB2984 against gram-positive Staphylococcus aureus was 2 μmol/L,the minimum inhibitory concentration against gram-negative Escherichia coli was 2 μmol/L,and the minimum inhibitory concentration against the fungus Candida albicans was 8 μmol/L.(3)The active peptide QUB2984 had obvious inhibitory effect on human non-small cell lung cancer cells NCI-H838 at 10-5 mol/L concentration,and the hemolytic effect on horse red cells at 64 μmol/L concentration was 50%.(4)The results showed that QUB2984 had anti-bacterial and anti-cancer activity,and it had a positive charge of +3,which was conducive to contact with bacteria or cells.
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Objective To screen out specific aldosterone(ALD)antibodies using phage display technology and recom-binant antibody technology,providing raw materials for the research and development of ALD diagnostic kits.Methods Five healthy and clean New Zealand white rabbits were selected and immunized for the first time against the diluted ALD-keyhole limpet hemocyanin antigen(2 mg·L-1)using a multi-point injection method on the back,with a dose of 1 mg per rabbit.Immunization was administered again every 2 weeks,with a 50％reduction in dose.Starting from the third immunization,the ear vein blood of the rabbits was collected one week after each immunization.A chemiluminescent plate coated with 0.25 mg·L-1 ALD-bovine serum albumin antigen was used to measure serum titers via indirect and competitive methods.After the 5th immunization,the rabbit with high serum titers and good specificity was selected,and its spleen and bone marrow were removed.The spleen tissue was grinded,and RNA was extracted using TRIzol reagent in one step to obtain gene sequences in the variable region of light chain(VL)and the variable region of heavy chain(VH).The single-chain variable fragment(ScFv)was connected through the linker and constructed into the bacteriophage vector Pcomb3xss;then,it was carried to Escherichia coli TG1 through electrotransformation,and the ALD ScFv phage display library was constructed accordingly.Three to five rounds of enrichment screening were performed against the library.Monoclonal clones,identified by enzyme-linked immunosorbent assay(ELISA)competitive method,were selected for phage supernatant preparation,and a highly competitive clone sequence was obtained.The screened clone sequence was inserted into the pCMV3 expression vector,and the HEK293 cell was transfected using the transient transfection method after the plasmid was extracted.One week later,the supernatant was collected,and its purity and expression were identified by affinity chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).Results After the 5th immunization,the serum titers of 5 rabbits were indirectly tested,and the results showed that the serum titers of 4# and 5# white rabbits were still greater than 10,000 after being diluted by 32,000 times.The test results based on the competitive method showed that the ratio of low to high values in the plasma sample of 5#white rabbit was 2∶1,superior to that of other white rabbits.The 5# white rabbit was selected for phage library construction.The VL and VH gene fragments were amplified by conventional polymerase chain reaction,and then bridged into ScFv(VL+VH).The agar gel electrophoresis analysis showed that the size of the band was about 750 bp,which was consistent with the size of the originally designed fragment.ScFv was cleaved and electroporated into Escherichia coli TG1 to construct a phage library with a storage capacity of 4.73 × 108 cfu·mL-1.After 3 rounds of washing,300 monoclonal clones were selected from the outbound petri dishes to prepare monoclonal bacteriophages.The ELISA results showed a positive rate of 100％among the 300 clones,and 42 clones were tested positive for calibration competition,with a screening rate of 14％.The 42 positive clones were further subjected to clinical sample competition testing,and 16 monoclonal strains that met the requirements were screened.The 16 strains were retested,and the results of the two tests were consistent.After sequencing,6 antibody sequences were selected for construction and expression.After purification,SDS-PAGE reduced gel electrophoresis results showed that there were bands at positions 50,000 on the heavy chain and 25,000 on the light chain.Six highly affinitive and competitive rabbit ALD monoclonal antibodies were obtained.Conclusion Six highly affinitive and competitive rabbit ALD antibodies are successfully screened using phage display technology,which provides a reference method for the discovery of small molecule antibodies.The screened AD1 85 and AD277 antibodies show a competitive advantage twice that of the positive control in the competition of calibration and clinical samples,providing a possibility for the development of raw materials for ALD detection kits.
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Aims@#The aim of this study was to cultivate the fungus Aspergillus tubingensis (MO503), which was isolated and identified from Algerian soil using submerged fermentation. The focus was on the production of lipase, achieved through utilizing a minimal medium from agro-food industries. Specifically, the study investigated the potential of three waste sources – olive-pomace, Pistacia lentiscus fruit remains and olive mill wastewater as substrates for enhancing lipase production. @*Methodology and results@#The three aforementioned wastes were chosen to ascertain their value and determine the most cost-effective option. Factorial analysis of variance (ANOVA) was employed to evaluate the waste with a significant effect on lipase production, as this enables determining differences among the various waste sources. Growth monitoring revealed a maximum lipase activity of 1030 ± 0,039 U at pH 5.4 for olive pomace. A series of biochemical purification techniques displayed a visible band on the polyacrylamide gel obtained through SDS-PAGE. Lipolytic activity was evidenced by zymography in the presence of olive oil. The antibacterial activities of purified lipase exhibited a high sensitivity against Gram-negative bacteria compared to Gram-positive bacteria. @*Conclusion, significance and impact of study@#In addition to its activity against Gram-negative bacteria, the lipid degradation facilitated by these lipases in olive oil offers promising applications in the textile and therapeutic industries.
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Aims@#Microorganisms play a vital role in the breakdown of natural organic compounds and are valuable objects for worldwide enzyme production. The aim of this study was to identify favorable production conditions for Bacillus amyloliquefaciens D19 protease, followed by the purification and chemical characterization of this novel enzyme to assess its potential applications in various fields.@*Methodology and results@#In this study, favorable conditions of protease production from B. amyloliquefaciens D19 were determined using a medium containing soluble starch (1.5%), earthworm extract (1.0%), yeast extract (0.5%), NaCl (1.0%), at pH 7.0-8.0, 37 °C for 36 h with 150 rpm shaking condition. The protease was purified and had a molecular weight of about 23 kDa. The optimum condition for casein hydrolysis was at 40 °C and pH 6.5-7.0 in the presence of 1.0 mM Na+ or 5.0 mM Zn2+. The enzymatic activity was maintained at 75-100% at 30-50 °C and in pH 6.0-10.0. The values of Vmax and KM were also determined as 1547 U/mg and 6.33 mg/mL, respectively.@*Conclusion, significance and impact of study@#The identified optimal conditions will serve as the foundation for the production of the 23 kDa B. amyloliquefaciens D19 protease, one of the smallest proteases within the Bacillus genus. Moreover, its notable heat resistance, broad pH tolerance, high substrate catalysis and moderate substrate binding affinity make this enzyme a promising candidate for various applications in the food-feed and brewing industries.
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Background The serious air pollution of highway toll booths poses a high occupational exposure risk to toll collectors. It is urgent to develop purification methods suitable for airborne particles and microbial pathogens in highway toll booths. Objective To verify the purification effect of low temperature plasma air purifiers on airborne particles and microbes in highway toll booths. Methods Based on controlled-intervention design, we selected three toll booths in an expressway toll station as on-site experimental locations for 6 d (no-intervention period: the low-temperature plasma purifier was turned off in the first three days; intervention period: the purifier was turned on from 9:00 to 17:00 in the following three days). The indoor and outdoor PM2.5 and PM10 concentrations were continuously monitored during the study. At 9:00, 12:00, and 17:00 of every day during the experiment, indoor and outdoor air samples were collected to analyze the concentration of airborne culturable colonies with a plankton sampler. Airborne particle samples were collected in the outermost exit continuously from 9:00 to 17:00 every day during the experiment using a medium flow particulate sampler, and the species and relative abundance of fungi and bacteria contained in the samples were analyzed by gene sequencing. Independent-sample t test was used to compare the concentration of indoor PM2.5, PM10, and culturable colonies between the intervention period and the non-intervention period. α diversity analysis, β diversity analysis, and t test were used to compare the diversity and relative abundance of specific species of bacteria and fungi, as well as typical pathogenic bacteria and fungi in the samples between the non-intervention period and the intervention period to reflect the purification effect of low temperature plasma air purifier on airborne PM2.5, PM10, and microorganisms. Results During the intervention period, the mean indoor concentrations of PM2.5, PM10, and culturable colonies were lower than those of the no-intervention period (P<0.01 or P<0.001). The ratios of indoor to outdoor concentration (I/O) of PM2.5 and PM10 during the intervention period were significantly lower than those of the no-intervention period (P<0.001), except the I/O of culturable colonies. Compared with the average concentration at 9:00, the average cleaning rates at 12:00 and 17:00 for PM2.5 were 49.0% and 46.1%, for PM10 were 49.7% and 45.4%, for airborne culturable colonies were 50.8% and 49.9%, respectively. The β diversity analysis showed that there were significant differences in composition at the level of species of bacteria, and at the levels of genus and species of fungi between the intervention and the no-intervention periods. The relative abundances of 10 species of bacteria such as Lactobacillus and 7 species of fungi such as Torula in the intervention period were significantly lower than those in the non-intervention period, but the relative abundances of fungi such as unclassified_f_cladosporiaceae, trichomerium, and cercospora were higher (P<0.05). For typical pathogenic bacteria, the relative abundances of Lactobacillus and Clostridium_sensu_stricto_1 during the intervention period were 73.5% and 86.9% lower than those in the no-intervention period, and the relative abundance of Talaromyces was 53.5% lower (P<0.05). Conclusion Low temperature plasma air purifier has a good purification effect on indoor PM2.5, PM10, and culturable colonies in highway toll booths, and likely a limited effect on some fungi.
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@#Objective To optimize the expression conditions(expression and induction conditions)and purification methods(non-denaturing and denaturing purification)of recombinant Hq001 protein in salivary glands of Haemaphysalis qinghaiensis.Methods The recombinant plasmid pET-30a-Hq001 was transformed into competent cells E.coil BL21(DE3),E.coil Rosetta(DE3)and E.coil ArcticExpress(DE3)pRARE2 respectively for the selection of an optimal expression strain.The final concentration of IPTG(0,0.5,1.0 mmol/L),induction temperature(20,25 ℃)and induction time(0,2,4,6,8 h)were optimized.The recombinant bacteria expressed under the ideal induction condition were homogenized by French press and the target protein was purified by passing through a Ni-NTA affinity chromatography column under either native(denaturationrenaturation-column chromatography)or denatured conditions(denaturation-column chromatography-renaturation).The purified products were analyzed by 12% SDS-PAGE.Results E.coil BL21(DE3)was proved to be the most suitable strain for the expression of recombinant Hq001 protein.The optimum induction condition was induction with 0.5 mmol/L IPTG for 4 h at 25 ℃.The target protein with a relative molecular mass of approximately 18 800 was obtained by non-denaturing purification method,and the size was consistent with the expectation.Conclusion The recombinant protein rHq001 in salivary glands of Haemaphysalis qinghaiensis can be obtained by the optimized expression conditions and purification methods.
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Objective @#To explore and optimize the in vitro primary culture method of astrocytes in neonatal mouse cerebral cortex , which provides a better solution for the in vitro culture of astrocytes.@*Methods @#In order to optimize the in vitro culture method of mouse cerebral cortex astrocytes , 3 ⁃day⁃old C57BL/6J mouse cerebral cortex tissues were taken , meninges and blood vessels were removed , digested by pancreatic enzymes and centrifuged , andhigh⁃glucose dulbecco ′s modified eagle medium (DMEM) was added to form cell suspension , which was purified by differential adhesion method , cross hand method and constant temperature shaking method.The cells were inoculated in poly⁃D ⁃lysine⁃coated culture bottles with different culture densities , and the purity of astrocytes was determined by morphological ob servation and immunofluorescence staining.@*Results @#The cells were inoculated at a density of 5 × 106 cells per bottle with good effect and high activity. The purity of astrocytes reached 99% by using high sugar DMEM medium combined with differential adhesion method , cross hand method and constant temperature shaking method.@*Conclusion @#The primary culture method of astrocytes in mouse cerebral cortex is successfully established and optimized.
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Plant bioreactor is a new production platform for expression of recombinant protein, which is one of the cores of molecular farming. In this study, the anti DYKDDDDK (FLAG) antibody was recombinantly expressed in tobacco (Nicotiana benthamiana) and purified. FLAG antibody with high affinity was obtained after immunizing mice for several times and its sequence was determined. Based on this, virus vectors expressing heavy chain (HC) and light chain (LC) inoculated into Nicotiana benthamiana leaves by using Agrobacterium-mediated delivery. Accumulation of the HC and LC was analyzed by SDS/PAGE followed by Western blotting probed with specific antibodies from 2 to 9 days postinfiltration (dpi). Accumulation of the FLAG antibody displayed at 3 dpi, and reached a maximum at 5 dpi. It was estimated that 66 mg of antibody per kilogram of fresh leaves could be obtained. After separation and purification, the antibody was concentrated to 1 mg/mL. The 1:10 000 diluted antibody can probe with 1 ng/mL FLAG fused antigen well, indicating the high affinity of the FLAG antibody produced in plants. In conclusion, the plant bioreactor is able to produce high affinity FLAG antibodies, with the characteristics of simplicity, low cost and highly added value, which contains enormous potential for the rapid and abundant biosynthesis of antibodies.
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Animals , Mice , Antibodies , Nicotiana/genetics , Agrobacterium/genetics , Bioreactors , Blotting, WesternABSTRACT
Objective To investigate the therapeutic effect of continuous blood purification on diabetic lactic acidosis(DLA).Methods 60 DLA patients who were treated at our hospital Blood Purification Center from January 2020 to January 2023 were randomly divided into conventional treatment group(Con)and continuous blood purification group(CBP),with 30 cases in each group.The changes of anion gap(AG),pH,lactic acid(Lac),FPG,2 hPG,HbA1c,alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),serum creatinine(Scr),urea nitrogen(BUN),cystatin C(CysC),blood potassium(K+),C-reactive protein(C-RP),acute and chronic health evaluation scoring system Ⅱ(APACHEⅡ)and mortality within 28 days were compared between the two groups.Results After 48 h of treatment,the clearance rate of Lac in CBP group was higher than that in Con group(P<0.05).The pH value of CBP group was higher than Con group.The levels of AG,Lac,FPG,2 hPG,HbA1c,ALT,AST,TBIL,Scr,BUN,CysC,K+,C-RP and APACHEⅡ score were lower in CBP group than those in Con group(P<0.05).The 28-day mortality rate of the CBP group was lower than that of the Con group(P<0.05).Conclusion Continuous blood purification combined with routine treatment in DLA patients can increase Lac clearance and improve the prognosis.
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@#Objective To express,purify and identify human monomolecular antibody against Clostridium perfringens type A α-toxin,in order to lay a foundation for the prevention and treatment of various diseases caused by this toxin.Methods The fully human single-chain fragment variable(ScFv) gene against Clostridium perfringens type A was linked with the constant region of light chain and heavy chain of human antibody in different combinations to construct multiple monomolecular antibody expression plasmids against Clostridium perfringens α-toxin,which were expressed in competent E.coLi BL21(DE3).Indirect ELISA was used to detect the immunobinding activity of the monomolecular antibodies,and the monomolecular antibody with the highest immunobinding activity was purified by SepharoSe 4 FF and rProtein-A FF affinity chromatography,The purified products were analyzed by 12% SDS-PAGE.Indirect ELISA was used to detect the immune binding activity of each monomolecular antibody.Results Five recombinant plasmids,PTS-ScFv-CL-CH_2-CH_3,PTS-ScFv-CH_2-CH_3,PTS-ScFv-CL-CH_2,PTS-ScFvCH_2,and PTS-ScFv-CL,were constructed.After transfection into E.coli BL21(DE3) and purification,the corresponding monomolecular antibodies,ScFv-CL-CH_2-CH_3,ScFv-CH_2-CH_3,ScFv-CL-CH_2,ScFv-CH_2,and ScFv-CL,were obtained,which had the relative molecular mass of about 60 000,and the concentrations of about 1 mg/mL.Among them,ScFv-CH_2-CH_3showed the highest immune binding activity,and the A_(450) value reached 3.9,much higher than the other four monomolecular antibodies,with the concentration of about 1 mg/mL and the purity about 86%.Conclusion A fully human monomolecular antibody ScFv-CH_2-CH_3 with high affinity,low immunogenicity and internalization activity was obtained,which lays a foundation for the further study of therapeutic antibody against CPA.
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ABSTRACT Blood purification as an adjunctive therapy has been studied for several decades. In this review, we will focus on the most recent studies, particularly on adsorption techniques. These include hemofilters with adsorptive membranes, both endotoxin-specific and non-specific. In addition, we will discuss sorbents that target endotoxins, as well as devices that non-selectively capture viruses and bacteria. For each technique, we will also explore the reasons why blood purification methods have thus far failed to improve survival. Conventionally, reasons for the lack of success in blood purification techniques have been attributed to the need for better patient stratification through bedside measurements of interleukins and endotoxins. The choice of assay is also crucial, with endotoxin activity assays being preferable to other forms of limulus amoebocyte lysate assays. Another critical factor is timing, as administering blood purification at the wrong moment can potentially harm the patient. Mechanistic studies are still lacking for most devices, leaving us to treat patients blindly, except in endotoxin cases. In the context of viruses, especially COVID-19, we require a deeper understanding of the complexities involved in viral replication, as this could significantly impact the efficacy of blood purification techniques. The failures highlighted for each device should be viewed as potential areas for improvement. Despite the challenges, we remain hopeful that these techniques will eventually succeed and prove beneficial in the future.
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In this paper, the main objective was to raise chickens’ antibodies against three crucial public health microorganisms: the human immunodeficiency virus-1, Salmonella spp, and Staphylococcus aureus. Immunogens were prepared from the said microorganisms. Chickens were vaccinated either orally or intramuscularly. After a booster immunization, mostly eggs were collected and assess for the presence of specific antibodies. The most important results were the production of a large amount of anti-HIV antibodies in chicken’s eggs, and also the synthesis of anti-protein a antibodies with the ability to inhibit the growth of S. aureus in vitro and to serve as anti-anti-idiotypic antibodies with the capacity of neutralizing the original antigen. Enzyme- linked immune absorbent assays detected the presence of these antibodies as anti-Salmonella antibodies that were critical in reducing the bacterial load in the stomach and caeca compared with a control group. The vaccines were effective and safe, but more laboratory work, and economics have to be carried out to start a human trial.
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ABSTRACT Schirmer strips and conjunctival swabs are used in ophthalmology for the collection of tears and fluids. One of the biggest challenges during the COVID-19 pandemic has been accurate diagnosis and, in some cases, ocular manifestations are among the first symptoms. In this context, this study aimed to collect evidence to support the use of Schirmer strips and conjunctival swabs as a method of sample collection for viral analysis. A literature search was conducted following the Scoping Review protocol defined by The Joanna Briggs Institute. Studies were analyzed regarding virus research, collection methods, and sample analysis. The findings support that viruses can be detected on the ocular surface through analysis of Schirmer strips and conjunctival swabs. However, additional studies with larger samples and time data are necessary to confirm these conclusions.
RESUMO A fita de Schirmer e o swab conjunctival são utilizados na oftalmologia como métodos de coleta para lágrimas e fluidos. Durante a pandemia da COVID-19, um dos desafios foi o diagnóstico correto e se sabe que, em alguns casos, as manifestações oculares podem ser um dos primeiros sintomas. Nesse contexto, este estudo tem como objetivo levantar evidência que destaque o uso de fitas de Schirmer e de swabs conjuntivais como método de coleta para análise viral. Conduziu-se uma revisão de literatura seguindo o protocolo para Scoping Review definido pelo Joanna Briggs Institute. Os pesquisadores analisaram os estudos em busca do vírus pesquisado, os métodos de coleta e os métodos de análise. Vírus podem ser detectados na superfície ocular através da análise de fitas de Schirmer e de swabs conjuntivais, entretanto novos estudos com populações maiores e com definições claras de tempo são necessários para conclusões mais assertivas no tema.
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ABSTRACT Staphylococcus hominis (S. hominis) is a coagulase-negative Staphylococci and an infrequent cause of endophthalmitis. Due to its ability to produce biofilm, especially in diabetic patients, strains may acquire antibiotic resistance. We present two cases of S. hominis endophthalmitis, one with acute endophthalmitis after intravitreal bevacizumab injection and one with chronic endophthalmitis following undiagnosed penetrating ocular trauma. Although there are only four published S. hominis endophthalmitis cases in the literature, to the best of our knowledge, there has been no previously published case after intravitreal bevacizumab.
RESUMO Staphylococcus hominis (S. hominis) é um estafilococo coagulase-negativo e uma causa pouco frequente de endoftalmite. Devido à sua capacidade de produzir biofilme, especialmente em pacientes diabéticos, cepas dessa bactéria podem adquirir resistência a antibióticos. Este relato apresenta dois casos de endoftalmite por S. hominis: um de endoftalmite aguda após injeção intravítrea de bevacizumabe e outro de endoftalmite crônica após trauma ocular penetrante não diagnosticado. Embora existam apenas quatro casos de endoftalmite por S. hominis publicados na literatura, até onde sabemos não houve nenhum caso publicado anteriormente após bevacizumabe intravítreo.
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Resumen La uroporfirinógeno descarboxilasa humana (UROD-h) es la quinta enzima del camino biosintético del hemo y su actividad deficiente, relacionada a mutaciones en su gen, se encuentra asociada a un subgrupo de porfirias. El objetivo de este trabajo fue estudiar la relación entre la dimerización de la enzima y su actividad enzimática y comprobar si la dimerización de UROD-h es imprescindible tanto para la primera etapa de la reacción (urogen→heptagen), como para la segunda etapa (heptagen→coprogen). Con ese objetivo, se expresó y purificó la UROD-h hasta homogeneidad, se analizó el comportamiento dímero-monómero bajo distintas condiciones que pudieran desplazar el equilibrio de dimerización y se evaluó la actividad enzimática en dichas condiciones. Los resultados obtenidos sugieren que la especie activa para la primera etapa de la reacción es el homodímero y que tanto el dímero como el monómero se comportan como especies activas para la segunda etapa de la reacción. Se propone que mutaciones clínicas como la Y311C, existentes en pacientes con porfiria cutánea tarda, podrían afectar la estabilidad del dímero y podrían ser el blanco para futuras terapias génicas.
Abstract Human uroporphyrinogen decarboxylase (UROD-h) is the fifth enzyme in the heme biosynthetic pathway and its deficient activity, related to mutations in its gene, is associated with a subset of porphyrias. The objective of this work was to study the relationship between the dimerisation of the enzyme and its enzymatic activity and to verify if the dimerisation of UROD-h is essential both for the first stage of the reaction (urogen→heptagen), and for the second stage (heptagen→ coprogen). With this objective, the UROD-h was expressed and purified to homogeneity, the dimer- monomer behaviour was analysed under different conditions, which could shift the dimerisation equilibrium, and the enzymatic activity was evaluated under these conditions. The results obtained suggest that the active species for the first stage of the reaction is the homodimer, and both the dimer and the monomer behaved as active species for the second stage of the reaction. It is proposed that clinical mutations such as Y311C, existing in porphyria cutanea tarda patients, could affect dimer stability and could be the target of future gene therapies.
Resumo A enzima uroporfirinogênio descarboxilase humana (UROD-h) é a quinta enzima da via biossintética do heme e sua atividade deficiente, relacionada com mutações em seu gene, está associada a um subgrupo de porfirias. O objetivo deste trabalho foi estudar a relação entre a dimerização da enzima e sua atividade enzimática e comprovar se a dimerização da UROD-h é imprescindível tanto para a primeira etapa da reação (urogênio→heptagênio), quanto para a segunda etapa (heptagênio→coprogênio). Com esse objetivo, a UROD-h foi expressa e purificada até a homogeneidade, o comportamento de dímero-monômero foi analisado sob diversas condições, que puderam deslocar o equilíbrio de dimerização, e a atividade enzimática foi avaliada em tais condições. Os resultados obtidos sugerem que a espécie ativa para a primeira etapa da reação é o homodímero, e tanto o dímero quanto o monômero se comportam como espécies ativas para a segunda etapa da reação. Propõe-se que mutações clínicas como Y311C, existentes em pacientes com porfiria cutânea tardia, poderiam afetar a estabilidade do dímero e poderiam ser o alvo de futuras terapias gênicas em porfiria cutânea tardia.
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@#ObjectiveTo obtain recombinant H.pylori adhesin A(rHpaA)by molecular cloning,protein expression and purification,immunize BALB/c mice to prepare anti-HpaA polyclonal antibody,and analyze its antibody specificity.MethodsThe three-dimensional structure and antigenic properties of rHpaA were analyzed by bioinformatics softwares such as Phyre2 and DNAstar;Adhesin HpaA gene was obtained by PAS(PCR-based accurate synthesis)and inserted into plasmid pCzn1.The prepared recombinant plasmid pCzn1-rHpaA was transformed to E.coli Artic Express(DE3),induced by IPTG and purified by Ni-IDA affinity chromatography to obtain rHpaA protein,which was identified for reactivity by Western blot.Six male BALB/c mice were immunized with rHpaA plus Freund's adjuvant to prepare anti-HpaA polyclonal anti-body,and the antibody specificity was identified by ELISA.ResultsrHpaA showed good three-dimensional structure and antigenic properties.Restriction analysis and gene sequencing showed that the recombinant plasmid pCzn1-rHpaA contained completely correct HpaA gene sequence.The recombinant strain pCzn1-rHpaA/Arctic Express expressed the soluble target protein rHpaA,which accounted for about 68.3% of total protein in the supernatant,with a purity of 98.1%.rHpaA bound to anti-His antibodies and anti-H.pylori antibodies;The anti-HpaA polyclonal antibody specifically recognized rHpaA and H.pylori lysates.ConclusionrHpaA protein with high purity can be obtained by induction at low temperature and purification.The prepared anti-HpaA polyclonal antibody had good specificity,which laid an experimental foundation of the development of H.pylori-related diagnostic reagents.
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@#ObjectiveTo optimize the condition for anion exchange chromatography in purification process of recombinant human growth hormone-Fc(rhGH-Fc)fusion protein by Design of Experiment(DOE)so as to decrease the content of host cell protein(HCP)in bulk of protein.MethodsA complete factorial experimental design with four factors at two levels was established by the DOE in Minitab 19 software.The condition(flow rate,sample load,pH value of buffer and salt concentration of eluent)for anion exchange chromatography in purification process of rhGH-Fc was optimized by DOE to find out the operating space.ResultsThe experimental results were predicted accurately by the established DOE model.The sample load,pH value of buffer,salt concentration of eluent as well as the interaction of pH value of buffer and salt concentration of eluent showed significant influence on the HCP content in the harvest.The optimal sample load,flow rate as well as pH value and salt concentration of eluent were 15 mg/mL,120 cm/h,7.0 ～ 8.0 and 0.1 mol/L respectively.The HCP contents in eluents under the optimal condition were less than 400 ng/mg,which met the requirements for verification within the range of results in determined operating space.ConclusionThe condition for removal of HCP by anion exchange chromatography was successfully optimized by DOE,which provided a reference for further application of DOE in the biopharmaceutical field.
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@#ObjectiveTo explore the purification effect of hepatitis A virus(HAV)with a new type of composite medium Capto Core 400 chromatography packing.MethodsHAV crude liquid cultured with human embryonic lung diploid cells(2BS strain)was purified using Capto Core 400 chromatography media. The optimum conditions for purification of HAV were determined from flow rates(60,150,300 and 450 cm/h),pH of loading buffer(6. 6,7. 0 and 7. 4),salt ion concentration of loading buffer(0,0. 15,0. 3 and 0. 45 mol/L)and capacity[0. 5,1,2 and 4 column volume(CV)],respectively. The purification effect was compared with that of traditional Sepharose 4FF chromatography media.Results The optimum purification conditions of Capto Core 400 were preliminarily determined as follows:flow rate of 150 cm/h,loading buffer pH of 7. 0 ～ 7. 4,salt ion concentration of 0. 15 mol/L,loading volume of 2 CV. The average recovery rate of virus was 92. 61%,and the average removal rate of protein was 84. 25%. The average recovery rate of HAV antigen purified by Sepharose 4FF chromatography media was 76. 03% and the average protein removal rate was 73. 21%. The purification effect of Capto Core 400 chromatography media was better than that of Sepharose 4FF chromatography media.ConclusionThe Capto Core 400 composite chromatography media had a high recovery rate for HAV purification and a relatively simple operation,which was suitable for HAV purification.
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ObjectiveTo analyze the clinical features， treatment and prognosis of patients with respiratory depression caused by glufosinate poisoning. MethodsThe clinical data of patients with respiratory depression caused by glufosinate poisoning admitted to the ICU of Xiangshan first people’s hospital medical and health group from March 2018 to January 2022 were retrospectively analyzed. ResultsA total of 21 patients with respiratory depression caused by glufosinate poisoning were included. The median （interquartile） intake of glufosinate was 30 （20， 40） g， and the median （interquartile） visit time was within 2.0 （1.0， 2.8） h. The initial symptoms were nausea and vomiting in 16 cases （76.2%）， and sore throat in 8 cases （38.1%）. Respiratory depression， convulsions and shock occurred 6‒48 hours after ingestion of glufosinate. Convulsion occurred in 13 cases （61.9%）， shock in 10 cases （47.6%） and bradycardia in 5 cases （23.8 %）. Among the patients with convulsion or shock， respiratory depression occurred earlier than convulsion and shock in 10 cases （76.9%） and 9 cases （90.0%）， respectively. All patients were treated with gastric lavage， catharsis， mechanical ventilation and symptomatic support. Blood purification was performed in 14 cases. The duration of mechanical ventilation was 5.0 （4.0， 7.0） d，and no patient died. The patients were divided into blood purification group and routine treatment group. There was no significant difference in complications and duration of mechanical ventilation between the blood purification group and the routine treatment group （P>0.05）. ConclusionRespiratory depression caused by glufosinate poisoning usually occurs earlier than convulsion and shock. The overall prognosis of patients with respiratory depression caused by glufosinate poisoning is good， which mainly depends on the early recognition and intervention of respiratory depression.
ABSTRACT
PET (polyethylene terephthalate) is one of the most important petrochemicals that is widely used in mineral water bottles, food and beverage packaging and textile industry. Because of its stability under environmental conditions, the massive amount of PET wastes caused serious environmental pollution. The use of enzymes to depolymerize PET wastes and upcycling is one of the important directions for plastics pollution control, among which the key is the depolymerization efficiency of PET by PET hydrolase. BHET (bis(hydroxyethyl) terephthalate) is the main intermediate of PET hydrolysis, its accumulation can hinder the degradation efficiency of PET hydrolase significantly, and the synergistic use of PET hydrolase and BHET hydrolase can improve the PET hydrolysis efficiency. In this study, a dienolactone hydrolase from Hydrogenobacter thermophilus which can degrade BHET (HtBHETase) was identified. After heterologous expression in Escherichia coli and purification, the enzymatic properties of HtBHETase were studied. HtBHETase shows higher catalytic activity towards esters with short carbon chains such as p-nitrophenol acetate. The optimal pH and temperature of the reaction with BHET were 5.0 and 55 ℃, respectively. HtBHETase exhibited excellent thermostability, and retained over 80% residual activity after treatment at 80 ℃ for 1 hour. These results indicate that HtBHETase has potential in biological PET depolymerization, which may facilitate the enzymatic degradation of PET.