Hyaluronate lyases were obtained from two types of naturally isolated bacterial strains Paenibacillus yunnanensis and Paennarthrobacter nicotinovorans.PyHL(form P.yunnanensis)in the culture supernatant of the bacteria...Hyaluronate lyases were obtained from two types of naturally isolated bacterial strains Paenibacillus yunnanensis and Paennarthrobacter nicotinovorans.PyHL(form P.yunnanensis)in the culture supernatant of the bacteria was purified by two steps of column chromatography.The enzyme showed the molecular mass of 74 kDa by SDS-PAGE and the maximal activity at pH 5.0,35℃.PyHL maximally degraded hyaluronate by an endo-type manner,and showed low degradation activity toward chondroitin sulfates.Dermatan sulfate was not the substrate.PnHL(from P.nicotinovorans)in the culture supernatant of the bacteria was purified by two steps of column chromatography.The enzyme showed the molecular mass of 70 kDa by SDS-PAGE and the maximal activity at pH 6.0,30℃.Genomic analysis of P.nicotinovorans on the bases of the internal amino acid sequences of PnHL.展开更多
Background: Hepatocellular carcinoma(HCC) is one of the most highly malignant tumors. Liver tumor-initiating cells(LTICs) have been considered to contribute to HCC progression and metastasis. ATP-citrate lyase(ACLY), ...Background: Hepatocellular carcinoma(HCC) is one of the most highly malignant tumors. Liver tumor-initiating cells(LTICs) have been considered to contribute to HCC progression and metastasis. ATP-citrate lyase(ACLY), as a key enzyme for de novo lipogenesis, has been reported to be upregulated in various tumors. However, its expression and role in HCC and LTICs remain unknown. Methods: The expressions of ACLY in HCC tissues were detected by quantitative real-time PCR(q RT-PCR), Western blotting and immunohistochemistry. Kaplan-Meier curves and Chi-square test were used to determine the clinical significance of ACLY expression in HCC patients. A series of assays were performed to determine the function of ACLY on stemness, migration and invasion of HCC cells. Luciferase reporter assay, Western blotting and immunoprecipitation were used to study the regulation of the Wnt/β-catenin signaling by ACLY. Rescue experiments were performed to investigate whether β-catenin was the mediator of ACLY-regulated stemness and migration in HCC cells. Results: ACLY was highly expressed in HCC tissues and LTICs. Overexpression of ACLY was significantly correlated with poor prognosis, progression and metastasis of HCC patients. Knockdown of ACLY remarkably suppressed stemness properties, migration and invasion in HCC cells. Mechanistically, ACLY could regulate the canonical Wnt pathway by affecting the stability of β-catenin, and Lys49 acetylation of β-catenin might mediate ACLY-regulated β-catenin level in HCC cells. Conclusions: ACLY is a potent regulator of Wnt/β-catenin signaling in modulating LTICs stemness and metastasis in HCC. ACLY may serve as a new target for the diagnosis and treatment of HCC.展开更多
The soybean cyst nematode, Heterodeara glycines, is a serious pathogen of soybean, and reported to be the host of a wide range of Fabaceae. In the present study, the host specificity and reproductivity of two populati...The soybean cyst nematode, Heterodeara glycines, is a serious pathogen of soybean, and reported to be the host of a wide range of Fabaceae. In the present study, the host specificity and reproductivity of two populations of H. glycines collected from soybean and tobacco were identified and characterized. The comparative identity between β-1,4-endoglucanase, pectate lyase and chorismate mutase of H. glycines parasitizing on soybean and tobacco were 99, 97 and 98%, respectively. The qR T-PCR analysis indicated that the expression of pectate lyase 2 gene was significantly higher in second-stage juveniles of H. glycines Henan population parasitizing on tobacco than that of H. glycines Shanxi population parasitizing on soybean. In addition, the pectic acid content of cell wall was significantly higher(45%) in the roots of tobacco than the roots of soybean. Our results indicate that the changes in transcript parasitism genes may be a result of long-term evolution illustrating how a plant-parasitic nematode adapts to the host environment for optimal infestation and survival.展开更多
Dear Editor,In recent years,owing to the fact that antibiotic-resistant bacteria have become more and more prevalent,there has been a resurgence of interest in the use of bacteriophages.However,bacteriophage therapy r...Dear Editor,In recent years,owing to the fact that antibiotic-resistant bacteria have become more and more prevalent,there has been a resurgence of interest in the use of bacteriophages.However,bacteriophage therapy remains an underutilized option in modern medicine due to technical hurdles such as limited host range,narrow spectrum of展开更多
Seven bacterial clones with alginate-utilizing activity were isolated from rotten kelp. By activity test, the Vibrio sp. QD-5 with the potential alginate-degrading capability was chosen to carry out the draft genome s...Seven bacterial clones with alginate-utilizing activity were isolated from rotten kelp. By activity test, the Vibrio sp. QD-5 with the potential alginate-degrading capability was chosen to carry out the draft genome sequencing, and the result showed that the Vibrio sp. QD-5 containing an alginate lyase gene cluster. One of these genes, aly-IV, was cloned and characterized for the first time. After overexpression, Aly-IV, with a molecular mass of about 62 kDa and a theoretical isoelectric point (pI) of 5.12, was purified to a specific activity of 1 256.78 U/mg and showed highest activity at 35°C in the Tris-HCl buffer at pH of 8.9. Moreover, the enzyme activity was enhanced by the metal ions of Na+, K+ and Mg2+ under certain concentration. Aly-IV degraded favorably polyG blocks in an endo-type, yielding monomer and dimer as the main products. Due to its high substrate specificity, Aly-IV could be used as a potential tool for production of polyG oligosaccharides with low degree of polymerization (DP) and for determining the fine structure of alginate.展开更多
BACKGROUND Adenylosuccinate lyase(ADSL)deficiency is a rare autosomal-recessive defect of purine metabolism caused by mutation of the ADSL gene.It can cause severe neurological impairment and diverse clinical manifest...BACKGROUND Adenylosuccinate lyase(ADSL)deficiency is a rare autosomal-recessive defect of purine metabolism caused by mutation of the ADSL gene.It can cause severe neurological impairment and diverse clinical manifestations,including epilepsy.CASE SUMMARY Here,we describe a 3-year-old Chinese boy who had both psychomotor retardation and refractory epilepsy.Magnetic resonance imaging showed myelin hypoplasia.Electroencephalography findings supported a diagnosis of epilepsy.Whole-exon sequencing revealed the presence of a novel complex heterozygous mutation in the ADSL gene:The splicing mutation c.154-3C>G and the missense mutation c.71C>T(p.Pro24Leu).Considering the patient’s clinical presentation and genetic test results,the complex heterozygous mutation was predicted to prevent both ADSL alleles from producing normal ADSL,which may have led to ADSL deficiency.Finally,the child was diagnosed with ADSL deficiency.CONCLUSION We identified a novel complex heterozygous mutation in the ADSL gene associated with ADSL deficiency,thus expanding the known spectrum of pathogenic mutations that cause ADSL deficiency.Additionally,we describe epilepsy that occurs in patients with ADSL deficiency.展开更多
Organomercury lyase (MerB) overexpressed in <em>Escherichia coli</em> captured and decomposed organomercury compounds, and it has been detected by radioactive analysis with neutron irradiation. Genetically...Organomercury lyase (MerB) overexpressed in <em>Escherichia coli</em> captured and decomposed organomercury compounds, and it has been detected by radioactive analysis with neutron irradiation. Genetically modified <em>E. coli</em> captures a lot of mercury from a cultivation solution with about 80% recovery, when the bacteria are growing during 24 to 72 hours. Since the modified <em>E. coli</em> has no additive gene for mercury metabolism, the bacteria could hold mercury tightly by the MerB enzyme in their cell and do not release them into medium. In the later, 72 hours after, bacteria have less recovery ratio;it may be affected by undecompsed mercury compounds in bacteria growth. The recovery ability of the bacteria would not be changed by addition of the MerB producing reagent (IPTG). A quantitative value of mercury atom is estimated by an emission of <em>γ</em>-ray by reactor neutron from a dried cell or solution on a filter paper, which is available for nondestructive testing of bacteria holding mercury atoms. In this method an efficient recovery system of toxic mercury from a polluted solution has been archived without destruction of samples, so called <em>in-cell</em> analysis.展开更多
Cocoa (Theobroma cacao), in all its presentations, is consumed all over the world and is one of the main drivers of the economic in several countries. The world’s Cocoa tendency is focused on developing special beans...Cocoa (Theobroma cacao), in all its presentations, is consumed all over the world and is one of the main drivers of the economic in several countries. The world’s Cocoa tendency is focused on developing special beans. This category is subject to postharvest processes of utmost importance such as the fermentation and dry, which are currently carried out with traditional and poorly effective devices, which need to be improved to obtain a high quality product. The aim of this study was to evaluate the influence of the pectin lyase enzyme (E.C.4.2.2.10) on the postharvest cocoa process. We evaluated the enzyme dosage (1.0% and 0.5%) in fermentation and its effect on the variables temperature, acidity and drying time by convection at 60°C. The Pectin lyase activity during fermentation does not cause a significant effect on the variables of temperature and acidity;however, the drying process time required to achieve 7.0% moisture was reduced. The enzyme dosage of 1.0% was the best result, the amount of exudate obtained (115 ml) during fermentation and the best degree of fermentation (77% ± 3.8) were increased and further shows a change in porosity facilitating the scale surface and internal moisture diffusion. The drying rate (Nw) expressed in kg<sub>water</sub>/m<sup>2 *</sup> min was determined based on the empirical model of Newton, where the higher speed was obtained during the falling period. In conclusion, enzyme dosage 1% was the best concentration evaluated because weaken grain husk, which allowed an adequate fermentation,and subsequent time drying reduction until 10.8 h.展开更多
Background Sphingosine-1-phosphate lyase insufficiency syndrome(SPLIS)or nephrotic syndrome type-14 is caused by biallelic mutations in SGPL1.Here,we conducted a systematic review to delineate the characteristics of S...Background Sphingosine-1-phosphate lyase insufficiency syndrome(SPLIS)or nephrotic syndrome type-14 is caused by biallelic mutations in SGPL1.Here,we conducted a systematic review to delineate the characteristics of SPLIS patients.Methods A literature search was performed in PubMed,Web of Science,and Scopus databases,and eligible studies were included.For all patients,demographic,clinical,laboratory,and molecular data were collected and analyzed.Results Fifty-five SPLIS patients(54.9%male,45.1%female)were identified in 19 articles.Parental consanguinity and positive family history were reported in 70.9%and 52.7%of patients,respectively.Most patients(54.9%)primarily manifested within the first year of life,nearly half of whom survived,while all patients with a prenatal diagnosis of SPLIS(27.5%)died at a median[interquartile(IQR)]age of 2(1.4–5.3)months(P=0.003).The most prevalent clinical feature was endocrinopathies,including primary adrenal insufficiency(PAI)(71.2%)and hypothyroidism(32.7%).Kidney disorders(42,80.8%)were mainly in the form of steroid-resistant nephrotic syndrome(SRNS)and progressed to end-stage kidney disease(ESKD)in 19(36.5%)patients at a median(IQR)age of 6(1.4–42.6)months.Among 30 different mutations in SGPL1,the most common was c.665G>A(p.Arg222Gln)in 11(20%)patients.Twenty-six(49.1%)patients with available outcome were deceased at a median(IQR)age of 5(1.5–30.5)months,mostly following ESKD(23%)or sepsis/septic shock(23%).Conclusion In patients with PAI and/or SRNS,SGPL1 should be added to diagnostic genetic panels,which can provide an earlier diagnosis of SPLIS and prevention of ESKD and other life-threatening complications.展开更多
Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alt...Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alternative to a protein-restricted diet,oral intake of engineered probiotics degrading Phe inside the body is a promising treatment,currently at clinical stage II(Isabella,et al.,2018).However,limited transmembrane transport of Phe is a bottleneck to further improvement of the probiotic’s activity.Here,we achieved simultaneous degradation of Phe both intracellularly and extracellularly by expressing genes encoding the Phe-metabolizing enzyme phenylalanine ammonia lyase(PAL)as an intracellularly free and a cell surface-immobilized enzyme in Escherichia coli Nissle 1917(EcN)which overcomes the transportation problem.The metabolic engineering strategy was also combined with strengthening of Phe transportation,transportation of PAL-catalyzed trans-cinnamic acid and fixation of released ammonia.Administration of our final synthetic strain TYS8500 with PAL both displayed on the cell surface and expressed inside the cell to the Pah^(F263S)PKU mouse model reduced blood Phe concentration by 44.4%compared to the control Ec N,independent of dietary protein intake.TYS8500 shows great potential in future applications for PKU therapy.展开更多
Alginate,an acidic polysaccharide,is formed byβ-D-mannuronate(M)andα-L-guluronate(G).As a type of polysaccharide lyase,alginate lyase can efficiently degrade alginate into alginate oligosaccharides,having potential ...Alginate,an acidic polysaccharide,is formed byβ-D-mannuronate(M)andα-L-guluronate(G).As a type of polysaccharide lyase,alginate lyase can efficiently degrade alginate into alginate oligosaccharides,having potential applications in the food,medicine,and agriculture fields.However,the application of alginate lyase has been limited due to its low catalytic efficiency and poor temperature stability.In recent years,various structural features of alginate lyase have been determined,resulting in modification strategies that can increase the applicability of alginate lyase,making it important to summarize and discuss the current evidence.In this review,we summarized the structural features and catalytic mechanisms of alginate lyase.Molecular modification strategies,such as rational design,directed evolution,conserved domain recombination,and non-catalytic domain truncation,are also described in detail.Lastly,the application of alginate lyase is discussed.This comprehensive summary can inform future applications of alginate lyases.展开更多
It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentr...It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentration can promotes plant growth and produce tolerance against stress.This study was conducted in order to determine the effects of selenium(Se)application(0,4,8 and 16 mg L^-1)on phenylalanine ammonia-lyase(PAL)activity,phenol leakage and total phenolic content of garlic under salt stress(0,30,60 and 90 mM NaCl).The highest PAL activity was recorded at 60 and 90 mM NaCl salinity with application of 8mg Se L^-1.Also,when Se was added to the salt-stress garlic,the level of phenol leakage was decreased significantly at two levels of NaCl concentration(by 52%and 40%at 30 mM NaCl with application of 4 and 16 mg Se L^-1,and by 50%at 90 mM NaCl with application of 4mg Se L^-1,respectively)in comparison to the salt-stressed garlic without Se.The results showed that Se can increase the salt tolerance of garlic by protecting the cell membrane against lipid peroxidation.The highest concentration of phenols was recorded at 90 mM NaCl salinity level with application of 4 and 8 mg Se L^-1,that respectively produced 59%and 51%higher phenols than control treatment without Se.So,application of optimal Se level can increase the potential of garlic in a medium with relatively high level of NaCl.展开更多
Aryl hydrocarbon receptor(AhR),a cellular chemical sensor,controls cellular homeostasis,and sphingosine-1-phosphate(S1P),a bioactive intermediate of sphingolipid metabolism,is believed to have a role in immunity and i...Aryl hydrocarbon receptor(AhR),a cellular chemical sensor,controls cellular homeostasis,and sphingosine-1-phosphate(S1P),a bioactive intermediate of sphingolipid metabolism,is believed to have a role in immunity and inflammation,but their potential crosstalk is currently unknown.We aimed to determine whether there is a functional linkage between AhR signaling and sphingolipid metabolism.We showed that AhR ligands,including an environmental polycyclic aromatic hydrocarbon(PAH),induced S1P generation,and inhibited S1P lyase(S1PL)activity in resting cells,antigen/IgE-activated mast cells,and mouse lungs exposed to the AhR ligand alone or in combination with antigen challenge.The reduction of S1PL activity was due to AhR-mediated oxidation of S1PL at residue 317,which was reversible by the addition of an antioxidant or in cells with knockdown of the ORMDL3 gene encoding an ER transmembrane protein,whereas C317A S1PL mutant-transfected cells were resistant to the AhR-mediated effect.Furthermore,analysis of AhR ligand-treated cells showed a time-dependent increase of the ORMDL3–S1PL complex,which was confirmed by FRET analysis.This change increased the S1P levels,which in turn,induced mast cell degranulation via S1PR2 signaling.In addition,elevated levels of plasma S1P were found in children with asthma compared to non-asthmatic subjects.These results suggest a new regulatory pathway whereby the AhR–ligand axis induces ORMDL3-dependent S1P generation by inhibiting S1PL,which may contribute to the expression of allergic diseases.展开更多
Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstu...Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstuffs for monogastric animals.This study aimed to evaluate the ability of pre-selected Carbohydrate-Active enZymes(CAZymes)and sulfatases to degrade U.lactuca cell walls and release nutritive compounds.A databank of 199 recombinant CAZymes and sulfatases was tested in vitro for their action towards U.lactuca cell wall polysaccharides.The enzymes were incubated with the macroalga,either alone or in combination,to release reducing sugars and decrease fluorescence intensity of Calcofluor White stained cell walls.The individual action of a polysaccharide lyase family 25(PL25),an ulvan lyase,was shown to be the most efficient in cell wall disruption.The ulvan lyase treatment,in triplicate measures,promoted the release of 4.54 g/L(P<0.001)reducing sugars,a mono-and oligosaccharides release of 11.4 and 11.2 mmol/100 g of dried alga(P<0.01),respectively,and a decrease of 41.7%(P<0.001)in cell wall fluorescence,in comparison to control.The ability of ulvan lyase treatment to promote the release of nutritional compounds from alga biomass was also evaluated.A release of some monounsaturated fatty acids was observed,particularly the health beneficial 18:1c9(P<0.001).However,no significant release of total fatty acids(P>0.05),proteins(P?0.861)or pigments(P>0.05)was found.These results highlight the capacity of a single recombinant ulvan lyase(PL25 family)to incompletely disrupt U.lactuca cell walls.This enzyme could enhance the bioaccessibility of U.lactuca bioactive products with promising utilization in the feed industry.展开更多
In Gloeobacter violaceus PCC 7421, three possible lyase genes glr1191, glr1182 and gll1188 were selected by Blast sorting. The coded proteins of these three genes were co-expressed with their substrate protein in E. c...In Gloeobacter violaceus PCC 7421, three possible lyase genes glr1191, glr1182 and gll1188 were selected by Blast sorting. The coded proteins of these three genes were co-expressed with their substrate protein in E. coli, respectively, and some chromoproteins were obtained. The fluorescence spectra showed that high fluorescence intensity was observed in the three experimental groups that involved the lyase genes, but little fluorescence intensity was observed in negative control groups. The ratio of relative fluorescence intensity in the experimental group with glr1191 was 64.8%. The result of SDS-PAGE indicated that the molecular weights of the three chromoproteins were 22.0 10 3 , 23.6 10 3 and 22.1 10 3 , respectively. The result of zinc-induced fluorescence re- vealed that the phycobilin in the three chromoproteins was covalently coupled to their apo-proteins. The result also showed that the coded proteins of these three genes (CpeS1 , CpeT1 , CpeY )could cata- lyze the covalent coupling of different phycobilins to their apo- proteins and formed active chromoproteins.展开更多
Alginate lyase mainly produces active alginate oligosaccharides(AOS)by degrading alginate viaβ-elimination process.In this study,the Pseudoalteromonas sp.Alg6B alginate lyase-encoding gene alg6B-7 from polysaccharide...Alginate lyase mainly produces active alginate oligosaccharides(AOS)by degrading alginate viaβ-elimination process.In this study,the Pseudoalteromonas sp.Alg6B alginate lyase-encoding gene alg6B-7 from polysaccharide lyase(PL)-7 family was successfully cloned,sequenced,expressed in Escherichia coli.Based on rational design and amino acid sequence alignment of the alginate lyase from various sources,four positive mutants were obtained.The specific enzyme activities of four mutants I62A,A99K,V132S,and L157T were 38.84%,42.85%,75.8%and 51.83%higher than that of the wild enzyme,respectively.The K_(cat)/K_(m) values of the four mutants were both increased,and the catalytic efficiency of V132S was 1.92-fold higher than that of the wild enzyme,especially.The rational design that was employed in this study achieved the dramatic improvement of catalytic activity,which may provide the application potential in industrial production.展开更多
Benzaldehyde lyase(BAL)is an enzyme which was originally found from Pseudomonas fluorescens biovar I.It has long been used in the formation of a C-C bond.BAL can exclusively yield(R)-enantioselective products from the...Benzaldehyde lyase(BAL)is an enzyme which was originally found from Pseudomonas fluorescens biovar I.It has long been used in the formation of a C-C bond.BAL can exclusively yield(R)-enantioselective products from the synthesis ofα-hydroxy ketones and has so far been explored as an important enzyme to prepare the corresponding intermediate of pharmaceuticals.Due to its substrate spectrum and stereospecificity,this enzyme extends the synthetic potential for carboligations appreciably.In this review,we highlight the biotransformation applications of BAL in recent years,some of which have achieved intriguing results and provided the theoretical basis for drug development and industrial purpose in the future.展开更多
Quorum sensing(QS)system can dynamically control the expression of proteins along with the cell growth.The promoting period of QS system has been little focused on until now.In this study,a self-induced dynamic regula...Quorum sensing(QS)system can dynamically control the expression of proteins along with the cell growth.The promoting period of QS system has been little focused on until now.In this study,a self-induced dynamic regulated expression(SIDRE)system was constructed in Escherichia coli.To enable the system suitable for the expression of enzymes,promoter engineering was used to obtain P_(luxI)mutants.To test the SIDRE system,alginate lyase AL493 and esterase Est7 were used as target protein for expression.The enzyme activity of alginate lyase and esterase reached 96.38%and 106.71%of the control strains containing the T7 promoter.In high-density fermentation,the activity of alginate lyase expressed by the SIDRE system with P_(luxI)(T-38C)as promoter was 4.34-fold of that expressed by the T7 promoter.Therefore,the P_(luxI)mutants with different promoting periods and/or different strengths show great potential in both laboratory and industrial scale for protein expression.展开更多
Background Alginate oligosaccharide(AOS)holds great potential as a novel feed supplement in farm animals.However,the effects of AOS on chicken health and the underlying mechanisms are not fully understood.This study a...Background Alginate oligosaccharide(AOS)holds great potential as a novel feed supplement in farm animals.However,the effects of AOS on chicken health and the underlying mechanisms are not fully understood.This study aimed to optimize the enzymatic preparation of AOS by using bacterial alginate lyases expressed in yeast,investigate the effects of the prepared AOS on the growth performance and gut health of broiler chickens,and reveal the underlying mechanisms.Results Five alginate lyases from bacteria were cloned into Pichia pastoris GS115 and the alginate lyase PDE9 was expressed at relatively high yield,activity and stability in P.pastoris.Animal trials were carried out using 3201-day-old male Arbor Acres broilers(four groups;8 replicates/group×10 chicks/replicate)receiving either a basal diet or the same diet supplemented with 100,200 and 400 mg/kg PDE9-prepared AOS for 42 d.The results showed that dietary supplementation of 200 mg/kg AOS displayed the highest activity in promoting the birds’ADG and ADFI(P<0.05).AOS ameliorated the intestinal morphology,absorption function and barrier function,as indicated by the enhanced(P<0.05)intestinal villus height,maltase activity,and the expression of PEPT,SGLT1,ZNT1,and occludin.AOS also increased serum insulin-like growth factor-1,ghrelin(P<0.05),and growth hormone(P<0.1).Moreover,the concentrations of acetate,isobutyrate,isovalerate,valerate,and total SCFAs in cecum of birds fed AOS were significantly higher than the control birds(P<0.05).Metagenomic analysis indicated that AOS modulated the chicken gut microbiota structure,function,and microbial interactions and promoted the growth of SCFAs-producing bacteria,for example,Dorea sp.002160985;SCFAs,especially acetate,were found positively correlated with the chicken growth performance and growth-related hormone signals(P<0.05).We further verified that AOS can be utilized by Dorea sp.to grow and to produce acetate in vitro.Conclusions We demonstrated that the enzymatically produced AOS effectively promoted broiler chicken growth performance by modulating the chicken gut microbiota structure and function.For the first time,we established the connections among AOS,chicken gut microbiota/SCFAs,growth hormone signals and chicken growth performance.展开更多
文摘Hyaluronate lyases were obtained from two types of naturally isolated bacterial strains Paenibacillus yunnanensis and Paennarthrobacter nicotinovorans.PyHL(form P.yunnanensis)in the culture supernatant of the bacteria was purified by two steps of column chromatography.The enzyme showed the molecular mass of 74 kDa by SDS-PAGE and the maximal activity at pH 5.0,35℃.PyHL maximally degraded hyaluronate by an endo-type manner,and showed low degradation activity toward chondroitin sulfates.Dermatan sulfate was not the substrate.PnHL(from P.nicotinovorans)in the culture supernatant of the bacteria was purified by two steps of column chromatography.The enzyme showed the molecular mass of 70 kDa by SDS-PAGE and the maximal activity at pH 6.0,30℃.Genomic analysis of P.nicotinovorans on the bases of the internal amino acid sequences of PnHL.
基金supported by grants from the National Natu-ral Science Foundation of China (81972779)Ministry of Education (MOE) Key Laboratory on signaling Regulation and Targeting Therapy of Liver Cancer,and Shanghai Key Laboratory of Hepato-biliary Tumor Biology,Chinese National Key Project (2018ZX10723204-006-003)。
文摘Background: Hepatocellular carcinoma(HCC) is one of the most highly malignant tumors. Liver tumor-initiating cells(LTICs) have been considered to contribute to HCC progression and metastasis. ATP-citrate lyase(ACLY), as a key enzyme for de novo lipogenesis, has been reported to be upregulated in various tumors. However, its expression and role in HCC and LTICs remain unknown. Methods: The expressions of ACLY in HCC tissues were detected by quantitative real-time PCR(q RT-PCR), Western blotting and immunohistochemistry. Kaplan-Meier curves and Chi-square test were used to determine the clinical significance of ACLY expression in HCC patients. A series of assays were performed to determine the function of ACLY on stemness, migration and invasion of HCC cells. Luciferase reporter assay, Western blotting and immunoprecipitation were used to study the regulation of the Wnt/β-catenin signaling by ACLY. Rescue experiments were performed to investigate whether β-catenin was the mediator of ACLY-regulated stemness and migration in HCC cells. Results: ACLY was highly expressed in HCC tissues and LTICs. Overexpression of ACLY was significantly correlated with poor prognosis, progression and metastasis of HCC patients. Knockdown of ACLY remarkably suppressed stemness properties, migration and invasion in HCC cells. Mechanistically, ACLY could regulate the canonical Wnt pathway by affecting the stability of β-catenin, and Lys49 acetylation of β-catenin might mediate ACLY-regulated β-catenin level in HCC cells. Conclusions: ACLY is a potent regulator of Wnt/β-catenin signaling in modulating LTICs stemness and metastasis in HCC. ACLY may serve as a new target for the diagnosis and treatment of HCC.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest in China (201503114)
文摘The soybean cyst nematode, Heterodeara glycines, is a serious pathogen of soybean, and reported to be the host of a wide range of Fabaceae. In the present study, the host specificity and reproductivity of two populations of H. glycines collected from soybean and tobacco were identified and characterized. The comparative identity between β-1,4-endoglucanase, pectate lyase and chorismate mutase of H. glycines parasitizing on soybean and tobacco were 99, 97 and 98%, respectively. The qR T-PCR analysis indicated that the expression of pectate lyase 2 gene was significantly higher in second-stage juveniles of H. glycines Henan population parasitizing on tobacco than that of H. glycines Shanxi population parasitizing on soybean. In addition, the pectic acid content of cell wall was significantly higher(45%) in the roots of tobacco than the roots of soybean. Our results indicate that the changes in transcript parasitism genes may be a result of long-term evolution illustrating how a plant-parasitic nematode adapts to the host environment for optimal infestation and survival.
基金supported by the Natural Science Foundation of China(30571637)
文摘Dear Editor,In recent years,owing to the fact that antibiotic-resistant bacteria have become more and more prevalent,there has been a resurgence of interest in the use of bacteriophages.However,bacteriophage therapy remains an underutilized option in modern medicine due to technical hurdles such as limited host range,narrow spectrum of
基金The Marine Public Welfare Project of SOA under contract No.201505032the Scientific and Technological Innovation Project financially of Qingdao National Laboratory for Marine Science and Technology under contract No.2016ASKJ14
文摘Seven bacterial clones with alginate-utilizing activity were isolated from rotten kelp. By activity test, the Vibrio sp. QD-5 with the potential alginate-degrading capability was chosen to carry out the draft genome sequencing, and the result showed that the Vibrio sp. QD-5 containing an alginate lyase gene cluster. One of these genes, aly-IV, was cloned and characterized for the first time. After overexpression, Aly-IV, with a molecular mass of about 62 kDa and a theoretical isoelectric point (pI) of 5.12, was purified to a specific activity of 1 256.78 U/mg and showed highest activity at 35°C in the Tris-HCl buffer at pH of 8.9. Moreover, the enzyme activity was enhanced by the metal ions of Na+, K+ and Mg2+ under certain concentration. Aly-IV degraded favorably polyG blocks in an endo-type, yielding monomer and dimer as the main products. Due to its high substrate specificity, Aly-IV could be used as a potential tool for production of polyG oligosaccharides with low degree of polymerization (DP) and for determining the fine structure of alginate.
基金Supported by the Natural Science Foundation of Shandong Province,No.ZR2019MH060。
文摘BACKGROUND Adenylosuccinate lyase(ADSL)deficiency is a rare autosomal-recessive defect of purine metabolism caused by mutation of the ADSL gene.It can cause severe neurological impairment and diverse clinical manifestations,including epilepsy.CASE SUMMARY Here,we describe a 3-year-old Chinese boy who had both psychomotor retardation and refractory epilepsy.Magnetic resonance imaging showed myelin hypoplasia.Electroencephalography findings supported a diagnosis of epilepsy.Whole-exon sequencing revealed the presence of a novel complex heterozygous mutation in the ADSL gene:The splicing mutation c.154-3C>G and the missense mutation c.71C>T(p.Pro24Leu).Considering the patient’s clinical presentation and genetic test results,the complex heterozygous mutation was predicted to prevent both ADSL alleles from producing normal ADSL,which may have led to ADSL deficiency.Finally,the child was diagnosed with ADSL deficiency.CONCLUSION We identified a novel complex heterozygous mutation in the ADSL gene associated with ADSL deficiency,thus expanding the known spectrum of pathogenic mutations that cause ADSL deficiency.Additionally,we describe epilepsy that occurs in patients with ADSL deficiency.
文摘Organomercury lyase (MerB) overexpressed in <em>Escherichia coli</em> captured and decomposed organomercury compounds, and it has been detected by radioactive analysis with neutron irradiation. Genetically modified <em>E. coli</em> captures a lot of mercury from a cultivation solution with about 80% recovery, when the bacteria are growing during 24 to 72 hours. Since the modified <em>E. coli</em> has no additive gene for mercury metabolism, the bacteria could hold mercury tightly by the MerB enzyme in their cell and do not release them into medium. In the later, 72 hours after, bacteria have less recovery ratio;it may be affected by undecompsed mercury compounds in bacteria growth. The recovery ability of the bacteria would not be changed by addition of the MerB producing reagent (IPTG). A quantitative value of mercury atom is estimated by an emission of <em>γ</em>-ray by reactor neutron from a dried cell or solution on a filter paper, which is available for nondestructive testing of bacteria holding mercury atoms. In this method an efficient recovery system of toxic mercury from a polluted solution has been archived without destruction of samples, so called <em>in-cell</em> analysis.
文摘Cocoa (Theobroma cacao), in all its presentations, is consumed all over the world and is one of the main drivers of the economic in several countries. The world’s Cocoa tendency is focused on developing special beans. This category is subject to postharvest processes of utmost importance such as the fermentation and dry, which are currently carried out with traditional and poorly effective devices, which need to be improved to obtain a high quality product. The aim of this study was to evaluate the influence of the pectin lyase enzyme (E.C.4.2.2.10) on the postharvest cocoa process. We evaluated the enzyme dosage (1.0% and 0.5%) in fermentation and its effect on the variables temperature, acidity and drying time by convection at 60°C. The Pectin lyase activity during fermentation does not cause a significant effect on the variables of temperature and acidity;however, the drying process time required to achieve 7.0% moisture was reduced. The enzyme dosage of 1.0% was the best result, the amount of exudate obtained (115 ml) during fermentation and the best degree of fermentation (77% ± 3.8) were increased and further shows a change in porosity facilitating the scale surface and internal moisture diffusion. The drying rate (Nw) expressed in kg<sub>water</sub>/m<sup>2 *</sup> min was determined based on the empirical model of Newton, where the higher speed was obtained during the falling period. In conclusion, enzyme dosage 1% was the best concentration evaluated because weaken grain husk, which allowed an adequate fermentation,and subsequent time drying reduction until 10.8 h.
文摘Background Sphingosine-1-phosphate lyase insufficiency syndrome(SPLIS)or nephrotic syndrome type-14 is caused by biallelic mutations in SGPL1.Here,we conducted a systematic review to delineate the characteristics of SPLIS patients.Methods A literature search was performed in PubMed,Web of Science,and Scopus databases,and eligible studies were included.For all patients,demographic,clinical,laboratory,and molecular data were collected and analyzed.Results Fifty-five SPLIS patients(54.9%male,45.1%female)were identified in 19 articles.Parental consanguinity and positive family history were reported in 70.9%and 52.7%of patients,respectively.Most patients(54.9%)primarily manifested within the first year of life,nearly half of whom survived,while all patients with a prenatal diagnosis of SPLIS(27.5%)died at a median[interquartile(IQR)]age of 2(1.4–5.3)months(P=0.003).The most prevalent clinical feature was endocrinopathies,including primary adrenal insufficiency(PAI)(71.2%)and hypothyroidism(32.7%).Kidney disorders(42,80.8%)were mainly in the form of steroid-resistant nephrotic syndrome(SRNS)and progressed to end-stage kidney disease(ESKD)in 19(36.5%)patients at a median(IQR)age of 6(1.4–42.6)months.Among 30 different mutations in SGPL1,the most common was c.665G>A(p.Arg222Gln)in 11(20%)patients.Twenty-six(49.1%)patients with available outcome were deceased at a median(IQR)age of 5(1.5–30.5)months,mostly following ESKD(23%)or sepsis/septic shock(23%).Conclusion In patients with PAI and/or SRNS,SGPL1 should be added to diagnostic genetic panels,which can provide an earlier diagnosis of SPLIS and prevention of ESKD and other life-threatening complications.
基金supported by the National Natural Science Foundation of China(21825804,31921006)the National Science&Technology Major Project“Key New Drug Creation and Manufacturing Program”,China(2018ZX09711002-019)the Shanghai Municipal Science and Technology Major Project and the National Key Research and Development Program of China(2018YFA0800603)。
文摘Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alternative to a protein-restricted diet,oral intake of engineered probiotics degrading Phe inside the body is a promising treatment,currently at clinical stage II(Isabella,et al.,2018).However,limited transmembrane transport of Phe is a bottleneck to further improvement of the probiotic’s activity.Here,we achieved simultaneous degradation of Phe both intracellularly and extracellularly by expressing genes encoding the Phe-metabolizing enzyme phenylalanine ammonia lyase(PAL)as an intracellularly free and a cell surface-immobilized enzyme in Escherichia coli Nissle 1917(EcN)which overcomes the transportation problem.The metabolic engineering strategy was also combined with strengthening of Phe transportation,transportation of PAL-catalyzed trans-cinnamic acid and fixation of released ammonia.Administration of our final synthetic strain TYS8500 with PAL both displayed on the cell surface and expressed inside the cell to the Pah^(F263S)PKU mouse model reduced blood Phe concentration by 44.4%compared to the control Ec N,independent of dietary protein intake.TYS8500 shows great potential in future applications for PKU therapy.
基金supported by the National Natural Science Foundation of China(31601410)The Suqian City Science and Technology Project(L201906)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(KYCX20_1103)。
文摘Alginate,an acidic polysaccharide,is formed byβ-D-mannuronate(M)andα-L-guluronate(G).As a type of polysaccharide lyase,alginate lyase can efficiently degrade alginate into alginate oligosaccharides,having potential applications in the food,medicine,and agriculture fields.However,the application of alginate lyase has been limited due to its low catalytic efficiency and poor temperature stability.In recent years,various structural features of alginate lyase have been determined,resulting in modification strategies that can increase the applicability of alginate lyase,making it important to summarize and discuss the current evidence.In this review,we summarized the structural features and catalytic mechanisms of alginate lyase.Molecular modification strategies,such as rational design,directed evolution,conserved domain recombination,and non-catalytic domain truncation,are also described in detail.Lastly,the application of alginate lyase is discussed.This comprehensive summary can inform future applications of alginate lyases.
文摘It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentration can promotes plant growth and produce tolerance against stress.This study was conducted in order to determine the effects of selenium(Se)application(0,4,8 and 16 mg L^-1)on phenylalanine ammonia-lyase(PAL)activity,phenol leakage and total phenolic content of garlic under salt stress(0,30,60 and 90 mM NaCl).The highest PAL activity was recorded at 60 and 90 mM NaCl salinity with application of 8mg Se L^-1.Also,when Se was added to the salt-stress garlic,the level of phenol leakage was decreased significantly at two levels of NaCl concentration(by 52%and 40%at 30 mM NaCl with application of 4 and 16 mg Se L^-1,and by 50%at 90 mM NaCl with application of 4mg Se L^-1,respectively)in comparison to the salt-stressed garlic without Se.The results showed that Se can increase the salt tolerance of garlic by protecting the cell membrane against lipid peroxidation.The highest concentration of phenols was recorded at 90 mM NaCl salinity level with application of 4 and 8 mg Se L^-1,that respectively produced 59%and 51%higher phenols than control treatment without Se.So,application of optimal Se level can increase the potential of garlic in a medium with relatively high level of NaCl.
基金This work was supported,in part,by grants from the National Health Research Institutes,Taiwan(EOPP10-014 and EOSP07-014 to S.-K.H.)Kaohsiung Medical University“The Talent Plan”(105KMUOR04 to S.-K.H.)+6 种基金the Ministry of Science and Technology,Taiwan(MOST 105-2320-B-039-004 and MOST 106-2320-B-039-037,to H.-C.W.)China Medical University Hospital,Taiwan(DMR-106-154 and DMR-107-117,to H.-C.W.)the Community Medicine Research Center,Chang Gung Memorial Hospital at Keelung(CMRPG3E1183 to L.-C.C.)the 1000 Young Talents Plan Program,China(to Y.Z.)the Initial Funding for New PI,Fudan Children’s Hospital and Fudan University(to Y.Z.)the National Natural Science Foundation of China(81671561,to Y.Z.)the National Key Research and Development Program of China(2016YFC1305102,to Y.Z.)。
文摘Aryl hydrocarbon receptor(AhR),a cellular chemical sensor,controls cellular homeostasis,and sphingosine-1-phosphate(S1P),a bioactive intermediate of sphingolipid metabolism,is believed to have a role in immunity and inflammation,but their potential crosstalk is currently unknown.We aimed to determine whether there is a functional linkage between AhR signaling and sphingolipid metabolism.We showed that AhR ligands,including an environmental polycyclic aromatic hydrocarbon(PAH),induced S1P generation,and inhibited S1P lyase(S1PL)activity in resting cells,antigen/IgE-activated mast cells,and mouse lungs exposed to the AhR ligand alone or in combination with antigen challenge.The reduction of S1PL activity was due to AhR-mediated oxidation of S1PL at residue 317,which was reversible by the addition of an antioxidant or in cells with knockdown of the ORMDL3 gene encoding an ER transmembrane protein,whereas C317A S1PL mutant-transfected cells were resistant to the AhR-mediated effect.Furthermore,analysis of AhR ligand-treated cells showed a time-dependent increase of the ORMDL3–S1PL complex,which was confirmed by FRET analysis.This change increased the S1P levels,which in turn,induced mast cell degranulation via S1PR2 signaling.In addition,elevated levels of plasma S1P were found in children with asthma compared to non-asthmatic subjects.These results suggest a new regulatory pathway whereby the AhR–ligand axis induces ORMDL3-dependent S1P generation by inhibiting S1PL,which may contribute to the expression of allergic diseases.
基金Fundaçao para a Ciencia e Tecnologia(FCT,Lisbon,Portugal)through grant PTDC/CAL-ZOO/30238/2017 associated post-doc contract to MMC,CIISA(Project UIDB/00276/2020)a PhD fellowship to DFC(SFRH/BD/126198/2016).
文摘Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstuffs for monogastric animals.This study aimed to evaluate the ability of pre-selected Carbohydrate-Active enZymes(CAZymes)and sulfatases to degrade U.lactuca cell walls and release nutritive compounds.A databank of 199 recombinant CAZymes and sulfatases was tested in vitro for their action towards U.lactuca cell wall polysaccharides.The enzymes were incubated with the macroalga,either alone or in combination,to release reducing sugars and decrease fluorescence intensity of Calcofluor White stained cell walls.The individual action of a polysaccharide lyase family 25(PL25),an ulvan lyase,was shown to be the most efficient in cell wall disruption.The ulvan lyase treatment,in triplicate measures,promoted the release of 4.54 g/L(P<0.001)reducing sugars,a mono-and oligosaccharides release of 11.4 and 11.2 mmol/100 g of dried alga(P<0.01),respectively,and a decrease of 41.7%(P<0.001)in cell wall fluorescence,in comparison to control.The ability of ulvan lyase treatment to promote the release of nutritional compounds from alga biomass was also evaluated.A release of some monounsaturated fatty acids was observed,particularly the health beneficial 18:1c9(P<0.001).However,no significant release of total fatty acids(P>0.05),proteins(P?0.861)or pigments(P>0.05)was found.These results highlight the capacity of a single recombinant ulvan lyase(PL25 family)to incompletely disrupt U.lactuca cell walls.This enzyme could enhance the bioaccessibility of U.lactuca bioactive products with promising utilization in the feed industry.
基金Supported by the National Natural Science Foundation of China (30870519 and 30870541)
文摘In Gloeobacter violaceus PCC 7421, three possible lyase genes glr1191, glr1182 and gll1188 were selected by Blast sorting. The coded proteins of these three genes were co-expressed with their substrate protein in E. coli, respectively, and some chromoproteins were obtained. The fluorescence spectra showed that high fluorescence intensity was observed in the three experimental groups that involved the lyase genes, but little fluorescence intensity was observed in negative control groups. The ratio of relative fluorescence intensity in the experimental group with glr1191 was 64.8%. The result of SDS-PAGE indicated that the molecular weights of the three chromoproteins were 22.0 10 3 , 23.6 10 3 and 22.1 10 3 , respectively. The result of zinc-induced fluorescence re- vealed that the phycobilin in the three chromoproteins was covalently coupled to their apo-proteins. The result also showed that the coded proteins of these three genes (CpeS1 , CpeT1 , CpeY )could cata- lyze the covalent coupling of different phycobilins to their apo- proteins and formed active chromoproteins.
基金supported by the National First-class Discipline Program of the Light Industry Technology and Engineering(LITE2018-11).
文摘Alginate lyase mainly produces active alginate oligosaccharides(AOS)by degrading alginate viaβ-elimination process.In this study,the Pseudoalteromonas sp.Alg6B alginate lyase-encoding gene alg6B-7 from polysaccharide lyase(PL)-7 family was successfully cloned,sequenced,expressed in Escherichia coli.Based on rational design and amino acid sequence alignment of the alginate lyase from various sources,four positive mutants were obtained.The specific enzyme activities of four mutants I62A,A99K,V132S,and L157T were 38.84%,42.85%,75.8%and 51.83%higher than that of the wild enzyme,respectively.The K_(cat)/K_(m) values of the four mutants were both increased,and the catalytic efficiency of V132S was 1.92-fold higher than that of the wild enzyme,especially.The rational design that was employed in this study achieved the dramatic improvement of catalytic activity,which may provide the application potential in industrial production.
基金The author would like to thank Dr.K.Kaliyaperumal,Dr.M.Fredimoses and Dr.B.Sachin for their careful revisions of this work.
文摘Benzaldehyde lyase(BAL)is an enzyme which was originally found from Pseudomonas fluorescens biovar I.It has long been used in the formation of a C-C bond.BAL can exclusively yield(R)-enantioselective products from the synthesis ofα-hydroxy ketones and has so far been explored as an important enzyme to prepare the corresponding intermediate of pharmaceuticals.Due to its substrate spectrum and stereospecificity,this enzyme extends the synthetic potential for carboligations appreciably.In this review,we highlight the biotransformation applications of BAL in recent years,some of which have achieved intriguing results and provided the theoretical basis for drug development and industrial purpose in the future.
基金supported by the National Natural Science Foundation of China(31922072)Natural Science Foundation of Shandong Province(ZR2020JQ15)+3 种基金Project of Shandong Province Higher Educational Science and Technology Program(2019KJF012)Taishan Scholar Project of Shandong Province(tsqn201812020)China Agriculture Research System(CARS-48)Qingdao Science and Technology Demonstration and Guidance Project for Benefiting the People(20-3-4-28-nsh)。
文摘Quorum sensing(QS)system can dynamically control the expression of proteins along with the cell growth.The promoting period of QS system has been little focused on until now.In this study,a self-induced dynamic regulated expression(SIDRE)system was constructed in Escherichia coli.To enable the system suitable for the expression of enzymes,promoter engineering was used to obtain P_(luxI)mutants.To test the SIDRE system,alginate lyase AL493 and esterase Est7 were used as target protein for expression.The enzyme activity of alginate lyase and esterase reached 96.38%and 106.71%of the control strains containing the T7 promoter.In high-density fermentation,the activity of alginate lyase expressed by the SIDRE system with P_(luxI)(T-38C)as promoter was 4.34-fold of that expressed by the T7 promoter.Therefore,the P_(luxI)mutants with different promoting periods and/or different strengths show great potential in both laboratory and industrial scale for protein expression.
基金funded by the National Key Research and Development Program of China(2021YFD1800400)the Beijing Natural Science Foundation(6222032)the Starting Grants Program for Young Talents at China Agricultural University,the 2115 Talent Development Program of China Agricultural University and Chinese Universities Scientific Fund.
文摘Background Alginate oligosaccharide(AOS)holds great potential as a novel feed supplement in farm animals.However,the effects of AOS on chicken health and the underlying mechanisms are not fully understood.This study aimed to optimize the enzymatic preparation of AOS by using bacterial alginate lyases expressed in yeast,investigate the effects of the prepared AOS on the growth performance and gut health of broiler chickens,and reveal the underlying mechanisms.Results Five alginate lyases from bacteria were cloned into Pichia pastoris GS115 and the alginate lyase PDE9 was expressed at relatively high yield,activity and stability in P.pastoris.Animal trials were carried out using 3201-day-old male Arbor Acres broilers(four groups;8 replicates/group×10 chicks/replicate)receiving either a basal diet or the same diet supplemented with 100,200 and 400 mg/kg PDE9-prepared AOS for 42 d.The results showed that dietary supplementation of 200 mg/kg AOS displayed the highest activity in promoting the birds’ADG and ADFI(P<0.05).AOS ameliorated the intestinal morphology,absorption function and barrier function,as indicated by the enhanced(P<0.05)intestinal villus height,maltase activity,and the expression of PEPT,SGLT1,ZNT1,and occludin.AOS also increased serum insulin-like growth factor-1,ghrelin(P<0.05),and growth hormone(P<0.1).Moreover,the concentrations of acetate,isobutyrate,isovalerate,valerate,and total SCFAs in cecum of birds fed AOS were significantly higher than the control birds(P<0.05).Metagenomic analysis indicated that AOS modulated the chicken gut microbiota structure,function,and microbial interactions and promoted the growth of SCFAs-producing bacteria,for example,Dorea sp.002160985;SCFAs,especially acetate,were found positively correlated with the chicken growth performance and growth-related hormone signals(P<0.05).We further verified that AOS can be utilized by Dorea sp.to grow and to produce acetate in vitro.Conclusions We demonstrated that the enzymatically produced AOS effectively promoted broiler chicken growth performance by modulating the chicken gut microbiota structure and function.For the first time,we established the connections among AOS,chicken gut microbiota/SCFAs,growth hormone signals and chicken growth performance.
