Understanding interactions between viruses and their hosts is conducive to enabling better application of viruses as biocontrol agents.Certain viruses carried by parasitic wasps enhance the parasitic efficiency of was...Understanding interactions between viruses and their hosts is conducive to enabling better application of viruses as biocontrol agents.Certain viruses carried by parasitic wasps enhance the parasitic efficiency of wasp-larvae by protecting them against the immune system of their Lepidopteran host.However,the relationship between prey pests and viruses found in predatory natural enemies remains unclear.Herein,we report the interaction between Arma chinensis virus-1(AcV-1),originally isolated from a predatory natural enemy,Arma chinensis(Hemiptera:Pentatomidae),and one of its prey species,Spodoptera frugiperda(Lepidoptera:Noctuidae).The results showed that the AcV-1 virus appeared harmful to the novel host S.frugiperda by inhibiting larval diet consumption and increasing pupal mortality.Meanwhile,sequencing data indicated that the virus altered the gene expression profiles of S.frugiperda.KEGG analysis showed that the proteasome and phagosome pathways related to protein degradation and immune response were significantly enriched.Although the expression levels of digestive enzyme genes did not change significantly,the total protease activity of AcV-1 virus-positive individuals was significantly decreased,suggesting that the virus inhibited diet consumption of S.frugiperda via the down-regulation of digestive enzyme activities.These results indicate that a virus initially isolated in a predatory natural enemy can decrease the fitness of its prey species.The virus was found to impact the host proteasome and phagosome pathways related to protein degradation and immunity,providing a potential mechanism to enhance controlling efficiency.展开更多
BACKGROUND Colorectal cancer(CRC)is one very usual tumor together with higher death rate.Ubiquitin-specific protease 21(USP21)has been confirmed to take part into the regulation of CRC progression through serving as a...BACKGROUND Colorectal cancer(CRC)is one very usual tumor together with higher death rate.Ubiquitin-specific protease 21(USP21)has been confirmed to take part into the regulation of CRC progression through serving as a facilitator.Interestingly,the promotive function of USP21 has also discovered in the progression of CRC.ZEB1 has illustrated to be modulated by USP7,USP22 and USP51 in cancers.However,the regulatory functions of USP21 on ZEB1 in CRC progression need more invest-igations.AIM To investigate the relationship between USP21 and ZEB1 in CRC progression.METHODS The mRNA and protein expressions were assessed through RT-qPCR,western blot and IHC assay.The interaction between USP21 and ZEB1 was evaluated through Co-IP and GST pull down assays.The cell proliferation was detected through colony formation assay.The cell migration and invasion abilities were determined through Transwell assay.The stemness was tested through sphere formation assay.The tumor growth was evaluated through in vivo mice assay.RESULTS In this work,USP21 and ZEB1 exhibited higher expression in CRC,and resulted into poor prognosis.Moreover,the interaction between USP21 and ZEB1 was further investigated.It was demonstrated that USP21 contributed to the stability of ZEB1 through modulating ubiquitination level.In addition,USP21 streng-thened cell proliferation,migration and stemness through regulating ZEB1.At last,through in vivo assays,it was illustrated that USP21/ZEB1 axis aggravated tumor growth.CONCLUSION For the first time,these above findings manifested that USP21 promoted tumorigenicity and stemness of CRC by deubiquitinating and stabilizing ZEB1.This discovery suggested that USP21/ZEB1 axis may provide novel sights for the treatment of CRC.展开更多
Dry-cured meat products are considerably popular around the world due to unique flavor.Proteolysis is one of the enzymatic reactions from which flavor substances are derived,which is affected by endogenous proteases.T...Dry-cured meat products are considerably popular around the world due to unique flavor.Proteolysis is one of the enzymatic reactions from which flavor substances are derived,which is affected by endogenous proteases.The purpose aimed to reveal the potential relationship between endogenous proteases and key flavor substances in dry-cured pork coppa in this paper.The dynamic changes of endogenous proteases activity,free amino acids,and volatiles during dry-cured pork coppa processing were characterized.The results showed that 5 kinds of free amino acids,Glu,Lys,Val,Ala,and Leu,were identified as significant contributors to taste.Meanwhile,key volatiles,such as hexanal,nonanal,octanal,benzaldehyde,3-methyl butanoic acid,2-methyl propanoic acid,and ethyl octanoate,greatly contributed to the flavor characteristics of dry-cured pork coppa.Further partial correlation analysis was performed to better elucidate the relationship among parameters.The results revealed that close relationship between endogenous proteases and key substances.RAP not only significantly affected the accumulation of key active-amino acids,but also affected the accumulation of ethyl octanoate,2,3-pentanedione,and 2,3-octanedione by regulating the accumulation of octanoic acid and Leu.In addition,cathepsin B and D,DPP II,DPP IV and RAP notably affected accumulation of hexanal.展开更多
The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1...The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1 contains the receptor-binding domain(RBD),while the S2 contains the hydrophobic fusion domain for the entry into the host cell.Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various c leavage sites.In this article,we review host proteases including furin,trypsin,transmembrane protease serine 2(TMPRSS2)and cathepsins in the activation of SARS-CoV-2 S.Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin.The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2,and the binding triggers further conformational changes and exposure of the S2'site to proteases such as type Il transmembrane serine proteases(TTPRs)including TMPRSS2.In the presence of TMPRSS2 on the target cells,SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane.In the absence of TMPRSS2,SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry.Additional host proteases involved in the cleavage of the S were discussed.This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2,and discussed the dual roles of such inhibitors in virus replication.展开更多
BACKGROUND Recent advancements in biliary tract cancer(BTC)treatment have expanded beyond surgery to include adjuvant therapy,yet the prognosis remains poor.Identifying prognostic biomarkers could enhance the assessme...BACKGROUND Recent advancements in biliary tract cancer(BTC)treatment have expanded beyond surgery to include adjuvant therapy,yet the prognosis remains poor.Identifying prognostic biomarkers could enhance the assessment of patients who have undergone radical resection for BTC.AIM To determine transmembrane serine protease 4(TMPRSS4)utility as a prognostic biomarker of radical resection for BTC.METHODS Medical records of patients who underwent radical resection for BTC,excluding intrahepatic cholangiocarcinoma,were retrospectively reviewed.The associations between TMPRSS4 expression and clinicopathological factors,overall survival,and recurrence-free survival were analyzed.RESULTS Among the 85 patients undergoing radical resection for BTC,46(54%)were TMPRSS4-positive.The TMPRSS4-positive group exhibited significantly higher preoperative carbohydrate antigen 19-9(CA19-9)values and greater lymphatic invasion than the TMPRSS4-negative group(P=0.019 and 0.039,respectively).Postoperative overall survival and recurrence-free survival were significantly worse in the TMPRSS4-positive group(median survival time:25.3 months vs not reached,P<0.001;median survival time:28.7 months vs not reached,P=0.043,respectively).Multivariate overall survival analysis indicated TMPRSS4 positivity,pT3/T4,and resection status R1 were independently associated with poor prognosis(P=0.032,0.035 and 0.030,respectively).TMPRSS4 positivity correlated with preoperative CA19-9 values≥37 U/mL and pathological tumor size≥30 mm(P=0.016 and 0.038,respectively).CONCLUSION TMPRSS4 is a potential prognostic biomarker of radical resection for BTC.展开更多
Protease inhibitors promote herbivore resistance in diverse plant species.Although many inducible protease inhibitors have been identified,there are limited reports available on the biological relevance and molecular ...Protease inhibitors promote herbivore resistance in diverse plant species.Although many inducible protease inhibitors have been identified,there are limited reports available on the biological relevance and molecular basis of constitutive protease inhibitors in herbivore resistance.Here,we identified a serine protease inhibitor,CsSERPIN1,from the tea plant(Camellia sinensis).Expression of CsSERPIN1 was not strongly affected by the assessed biotic and abiotic stresses.In vitro and in vivo experiments showed that CsSERPIN1 strongly inhibited the activities of digestive protease activities of trypsin and chymotrypsin.Transient or heterologous expression of CsSERPIN1 significantly reduced herbivory by two destructive herbivores,the tea geometrid and fall armyworm,in tea and Arabidopsis plants,respectively.The expression of CsSERPIN1 in Arabidopsis did not negatively influence the growth of the plants under the measured parameters.Our findings suggest that CsSERPIN1 can inactivate gut digestive proteases and suppress the growth and development of herbivores,making it a promising candidate for pest prevention in agriculture.展开更多
The serine proteases of Mycobacteria tuberculosis(Mtb)are important contributors to the process of bacterial invasion and its pathogenesis.In the present study,we systematically characterized the role of the Rv1043c p...The serine proteases of Mycobacteria tuberculosis(Mtb)are important contributors to the process of bacterial invasion and its pathogenesis.In the present study,we systematically characterized the role of the Rv1043c protein in Mycobacterium infection by purifying the Rv1043c protein in Escherichia coli and constructing a Mycobacterium smegmatis(Msg)strain overexpressing Rv1043c(Msg_Rv1043c).We found that Rv1043c had serine protease activity and localized to the surface of Mtb.We determined that the optimal pH and temperature for the Rv1043c serine protease were 9.0 and 45°C,respectively.Moreover,the serine protease activity of Rv1043c was enhanced by divalent metal ions of Ca^(2+)and Mg^(2+).Site-directed mutagenesis studies demonstrated that the serine 279 residue in Rv1043c plays a catalytic role.Additionally,mouse model studies confirmed that Rv1043c significantly enhanced the survival of Msg in vivo,induced pulmonary injury and lung cell apoptosis,and promoted the release of pro-inflammatory cytokines interleukin-1βand interleukin-6 in mice.This study presents novel insights into the relationship between mycobacterial serine protease and the pathogenesis of the disease.展开更多
Female adults of the migratory locust,Locusta migratoria manilensis(Meyen),can sense seasonal photoperiod changes,which induces embryonic diapause as a key strategy to overwinter.Serine protease inhibitor genes(SPNs)w...Female adults of the migratory locust,Locusta migratoria manilensis(Meyen),can sense seasonal photoperiod changes,which induces embryonic diapause as a key strategy to overwinter.Serine protease inhibitor genes(SPNs)were thought to play key roles during diapause,while few SPNs were functionally characterized.LmSPN2 was one of those genes differentially expressed between diapause and non-diapause eggs;however,its biological function remained to be explored.So,we conducted RNAi knockdown of LmSPN2,resulting in a significant decrease of the egg diapause rate by 29.7%.Using yeast two-hybrid assays,co-immunoprecipitation,and pull-down methods,we found an interaction between LmSPN2 and LmSPN3,which was proved to be mediated by a glutamate(E331)binding site of LmSPN2.RNAi knockdown of LmSPN3 resulted in a significant increase in diapause rate by 14.6%,indicating an inverse function of LmSPN2 and LmSPN3 on diapause regulation.Double knockdown of two SPN genes resulted in a 26.4%reduction in diapause rate,indicating that LmSPN2 was the dominant regulatory signal.Moreover,we found four Toll pathway genes(easter,spätzle,pelle,and dorsal)upregulated significantly after the knockdown of LmSPN2 while downregulated after the knockdown of LmSPN3.Therefore,we speculate that two SPNs regulate diapause through the Toll pathway.Our results indicated that LmSPN2 positively regulates locust egg entry into diapause,while LmSPN3 is a negative regulator of embryonic commitment to diapause.Their interaction is mediated by the binding site of E331 and influences egg diapause through the Toll pathway.This mechanistic understanding of diapause regulation expands our understanding of insect developmental regulation and provides functional targets for developing locust management strategies.展开更多
In this study, a gene encoding serine protease(PmSpr288)from cold-adapted bacterium, namely Planococcus maritimus XJ11, was cloned and overexpressed in Escherichia coli BL21(DE3). Bioinformatics analysis revealed that...In this study, a gene encoding serine protease(PmSpr288)from cold-adapted bacterium, namely Planococcus maritimus XJ11, was cloned and overexpressed in Escherichia coli BL21(DE3). Bioinformatics analysis revealed that PmSpr288 belongs to serine protease S8 superfamily with a classical catalytic triad comprised by the Asp49, His86 and Ser251. Moreover, PmSpr288 was found to be active over broad alkaline pH and low-moderate temperature, and exhibited wide range of protein substrate specificity. In addition, PmSpr288 was able to hydrolyze the meat proteins actin and myosin, and molecular docking results suggested that the crucial interaction between PmSpr288 and actin/myosin complexes was mainly occupied by hydrogen bonds. The muscle protein hydrolysates of silver carp prepared by PmSpr288 was shown to have antioxidant activity via DPPH radical scavenging assay, which presented an IC_(50) valve of 1.309 mg/mL. In conclusion, these characteristics imply that PmSpr288 has potential biotechnological application prospect for the production of bioactive peptides.展开更多
Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃a...Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃and pH 7.0,and a desir-able extraction efficiency was achieved by using the crude collagenolytic protease.Dynamic light scattering,transmission electron microscopy and energy-dispersive X-ray analysis revealed that nano-HA are anionic spherical(about 110nm)particles mainly com-prised of calcium and phosphorus at an approximate ratio of 5:3.As evaluated with the mouse ex vivo intestinal segments,the extracted nano-HA displayed comparable level of intestinal bioavailability to the positive control CaCl_(2).By treating with inhibitors(NaN3,ami-loride)and low temperature(4℃),clathrin-mediated endocytosis was assumed to involve the intestinal absorption of nano-HA.Over-all,the application of thermostable collagenolytic protease is proved to be a promising alternative method for nano-HA extraction from natural resource with improved ecological and biological value.展开更多
Potato protease inhibitors(PPIs),as the main component of potato protein isolate,have good safety,nutrition and great market potential.The antioxidant and anticancer properties of PPIs were evaluated with cellbased bi...Potato protease inhibitors(PPIs),as the main component of potato protein isolate,have good safety,nutrition and great market potential.The antioxidant and anticancer properties of PPIs were evaluated with cellbased biological assays.The results showed that when the concentration of PPIs was 5 mg/mL,the peroxyl radical scavenging value was(2119±204)mg VCE/100 g,and the cellular antioxidant activity values were(45.83±3.5)(no PBS wash)and(33.25±4.4)μmol QE/100 g(PBS wash).Cells pretreated with PPIs could significantly prevent the oxidative damage induced by H_(2)O_(2),inhibit the morphological changes of cells and maintain the integrity.Furthermore,PPIs had selective anti-proliferative effects on GIST882 cells(IC50=(10.53±3.87)mg/mL)and demonstrated potent inhibition of the growth,migration and invasion of cancer cells.These findings provide a scientific basis for PPIs as promising candidates for functional foods to aid in the prevention of oxidative damage and cancer.展开更多
One of plant-based products for dental care is plant-based proteolytic enzymes which are principally proteases. In order not to damage the protein and bioactive content, an efficient method should be employed for thei...One of plant-based products for dental care is plant-based proteolytic enzymes which are principally proteases. In order not to damage the protein and bioactive content, an efficient method should be employed for their purifications. As such, three-phase partitioning (TPP) was used to purify protease from moringa (Moringa oleifera). TPP is an emerging, promising, non-chromatographic and economical technology which is simple, quick, efficient and often one-step process for the separation and purification of bioactive molecules from natural sources. It involves the addition of salt (ammonium sulphate) to the crude extract followed by the addition of an organic solvent (butanol). The protein appears as an interfacial precipitate between upper organic solvent and lower aqueous phases. The various conditions such as ammonium sulphate, ratio of crude extract to t-butanol and pH which are required for attaining efficient purification of the protease fractions were optimized. Under optimized conditions, it was seen that, 35% of ammonium sulphate saturation with 1:0.75 ratio of crude extract to t-butanol at pH 7 gave 4.94-fold purification with 96.20% activity yield of protease in the middle phase of the TPP system. The purified enzyme from Moringa oleifera has no antimicrobial effect on the pathogenic bacteria tested. However, this purified enzyme, can be considered as a promising agent, cheap, and safe source which is suitable for using in various industries.展开更多
The gastrointestinal barrier is-with approximately 400 m^2-the human body's largest surface separating the external environment from the internal milieu. This barrier serves a dual function: permitting the absorpt...The gastrointestinal barrier is-with approximately 400 m^2-the human body's largest surface separating the external environment from the internal milieu. This barrier serves a dual function: permitting the absorption of nutrients, water and electrolytes on the one hand, while limiting host contact with noxious luminal antigens on the other hand. To maintain this selective barrier, junction protein complexes seal the intercellular space between adjacent epithelial cells and regulate the paracellular transport. Increased intestinal permeability is associated with and suggested as a player in the pathophysiology of various gastrointestinal and extraintestinal diseases such as inflammatory bowel disease, celiac disease and type 1 diabetes. The gastrointestinal tract is exposed to high levels of endogenous and exogenous proteases, both in the lumen and in the mucosa. There is increasing evidence to suggest that a dysregulation of the protease/antiprotease balance in the gut contributes to epithelial damage and increased permeability. Excessive proteolysis leads to direct cleavage of intercellular junction proteins, or to opening of the junction proteins via activation of protease activated receptors. In addition, proteases regulate the activity and availability of cytokines and growth factors, which are also known modulators of intestinal permeability. This review aims at outlining the mechanisms by which proteases alter the intestinal permeability. More knowledge on the role of proteases in mucosal homeostasis and gastrointestinal barrier function will definitely contribute to the identification of new therapeutic targets for permeability-related diseases.展开更多
Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened...Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened protease-producing bacteria from the South China Sea sediments and analyzed the diversity of their extracellular proteases at the family level through N-terminal amino acid sequencing. Results of the 16 S rRNA gene sequence analysis showed that all screened protease-producing bacteria belonged to the class Gammaproteobacteria and most of them were affiliated with different genera within the orders Alteromonadales and Vibrionales. The Nterminal amino acid sequence analysis for fourteen extracellular proteases from fourteen screened bacterial strains revealed that all these proteases belonged to the M4 family of metalloproteases or the S8 family of serine proteases. This study presents new details on taxa of marine sedimentary protease-producing bacteria and types of their extracellular proteases, which will help to comprehensively understand the process and mechanism of the microbial enzymatic degradation of marine sedimentary organic nitrogen.展开更多
Snake venoms,especially those from the two subfamilies,Crotalinae and Viperinae,contained a lot of serine proteases. They were responsible for the hemorrhage,shock,or disorder of blood coagulation after envenomation. ...Snake venoms,especially those from the two subfamilies,Crotalinae and Viperinae,contained a lot of serine proteases. They were responsible for the hemorrhage,shock,or disorder of blood coagulation after envenomation. They acted,by activating,inactivating,or other converting effects,on almost all the components of hemostatic and fibrinolytic systems. Their sequences were homologous to trypsin-kallikrein serine proteases. Variation of primary sequences out of active center results in the difference of substrate specificities and the further difference of biological and pharmacological activities. Because of their common and unique properties compared to their physiological corresponding factors,snake venom proteases are proved to be an excellent model for the study of protease substrate discriminating mechanism. Furthermore,they have found an important position both in basic research and application of hemostasis and thrombosis in clinic.展开更多
[Objective] The study aimed to investigate the activity and gene expression of caspase-like proteases in tobacco leaves growing under different light qualities. [Method] By covering tobacco plants with white, red, yel...[Objective] The study aimed to investigate the activity and gene expression of caspase-like proteases in tobacco leaves growing under different light qualities. [Method] By covering tobacco plants with white, red, yellow, blue and purple films to obtain different light quality, the changes of chlorophyll content, activity and gene expression of caspase-like proteases in the tobacco leaves were studied. [Results] Compared with treatments of white, red and yellow film, blue and purple films delayed the decrease of chlorophyll content and senescence of tobacco leaves at the late growth stage, and relatively lowered the activity and gene expression of caspase-like proteases during growth, development and senescence periods. [Conclusion] Different light qualities exhibited various effects on the growth, development and senescence of tobacco leaves, possibly by affecting the activity and gene expression of caspase-like proteases to some extent.展开更多
Proteases, enzymes catalyzing the hydrolysis of peptide bonds, are present at high concentrations in the gastrointestinal tract. Besides their well-known role in the digestive process, they also function as signaling ...Proteases, enzymes catalyzing the hydrolysis of peptide bonds, are present at high concentrations in the gastrointestinal tract. Besides their well-known role in the digestive process, they also function as signaling molecules through the activation of protease-activated receptors(PARs). Based on their chemical mechanism for catalysis, proteases can be classified into several classes: serine, cysteine, aspartic, metallo- and threonine proteases represent the mammalian protease families. In particular, the class of serine proteases will play a significant role in this review. In the last decades, proteases have been suggested to play a key role in the pathogenesis of visceral hypersensitivity, which is a major factor contributing to abdominal pain in patients with inflammatory bowel diseases and/or irritable bowel syndrome. So far, only a few preclinical animal studies have investigated the effect of protease inhibitors specifically on visceral sensitivity while their effect on inflammation is described in more detail. In our accompanying review we describe their effect on gastrointestinal permeability. On account of their promising results in the field of visceral hypersensitivity, further research is warranted. The aim of this review is to give an overview on the concept of visceral hypersensitivity as well as on the physiological and pathophysiological functions of proteases herein.展开更多
[Objective] The aim of the study is to construct cDNA library of midgut tissue of wild silkworm and isolate the serine protease gene. [Method] The midgut tissue-specific cDNA library of wild silkworm was constructed v...[Objective] The aim of the study is to construct cDNA library of midgut tissue of wild silkworm and isolate the serine protease gene. [Method] The midgut tissue-specific cDNA library of wild silkworm was constructed via cDNA Library Construction Kit (TaKaRa), then the serine protease gene was cloned via sequencing of the yielded cDNA library. [Result] The titer of cDNA library reached 6.2×105 pfu/ml, average insert size was about 1.2 kb. The serine protease gene cDNA fragment was obtained from colony sequencing (Accession No: EU672968). The nucleotide sequence of the cloned 854 bp fragment encodes 284 amino acid residues. Homology analyses showed some homology between putative amino acid sequence of the cloned fragment and amino acid sequences of serine proteases from other ten insects. [Conclusion] The results may avail to reveal the resistance of silkworm and wild silkworm to exotic intrusion.展开更多
[Objective] The aim of the study was to provide the basis for researching the pathogenicity mechanism of Rhizoctonia solani.[Method] The extracellular protease was purified after ammonium sulfate precipitation through...[Objective] The aim of the study was to provide the basis for researching the pathogenicity mechanism of Rhizoctonia solani.[Method] The extracellular protease was purified after ammonium sulfate precipitation through DEAE-Sephrase Fast Flow,Phenyl-Sepharose Fast Flow and Sephadex G-75 ch rom atography. [Result] The extracellular protease with molecular weight of 49.5 ku was obtained from fermentation liquid of R. solani. The optimal temperature and pH value for its activity were 6.4 and 30 ℃ respectively. Zn^2＋,Fe^3＋,Cu^2＋had inhibition on enzyme activity,while Mg^2＋,Mn^2＋had no effect on enzyme activity,and Ca^2＋ could activate enzymatic activity in low concentration.[Conclusion] R. solani could secrete extracellular protease,but the relationship between the extracellular protease and the pathogenicity of R. solani required further study.展开更多
[Objective] The aim of this study was to study effects of metal ions on the protease activities in digestive tissues and gland of red-white ornamental carp（Cyprinus carpio L）.[Method] Effects of four kinds of metal ...[Objective] The aim of this study was to study effects of metal ions on the protease activities in digestive tissues and gland of red-white ornamental carp（Cyprinus carpio L）.[Method] Effects of four kinds of metal ions （K＋,Na＋,Mg2＋ and Ca2＋） on protease activities in hepatopancreas,foregut,midgut,hindgut of red-white ornamental carp were studied by enzyme analysis method.[Result] Effects of four kinds of metal ions on protease activities of red-white ornamental carp were different in the range of experimental concentration from 25 mmol/L to 150 mmol/L.K＋ could promote protease activities in hepatopancreas and hindgut at different levels.Especially,K＋ had the promoting effect at low-concentration level,but the inhibitory effect at high-concentration level in midgut and the inhibitory effect in foregut.Na＋ had the promoting effect on protease activities in hepatopancreas,foregut and hindgut at different levels,but the inhibitory effect in midgut.Mg2＋ and Ca2＋ had the inhibitory effect on protease activities in intestinal and hepatopancreas at different levels.[Conclusion] This study provides basic data and theoretical foundation for researches on the digestive physiology of red-white ornamental carp or the development and optimization of compound feed.展开更多
基金supported by the Major Special Projects for Green Pest Control,China(110202101028(LS-03),201938,110202201017(LS-01)and 110202001035(LS04))the National Natural Science Foundation of China(31901893)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(ASTIP-TRIC04)。
文摘Understanding interactions between viruses and their hosts is conducive to enabling better application of viruses as biocontrol agents.Certain viruses carried by parasitic wasps enhance the parasitic efficiency of wasp-larvae by protecting them against the immune system of their Lepidopteran host.However,the relationship between prey pests and viruses found in predatory natural enemies remains unclear.Herein,we report the interaction between Arma chinensis virus-1(AcV-1),originally isolated from a predatory natural enemy,Arma chinensis(Hemiptera:Pentatomidae),and one of its prey species,Spodoptera frugiperda(Lepidoptera:Noctuidae).The results showed that the AcV-1 virus appeared harmful to the novel host S.frugiperda by inhibiting larval diet consumption and increasing pupal mortality.Meanwhile,sequencing data indicated that the virus altered the gene expression profiles of S.frugiperda.KEGG analysis showed that the proteasome and phagosome pathways related to protein degradation and immune response were significantly enriched.Although the expression levels of digestive enzyme genes did not change significantly,the total protease activity of AcV-1 virus-positive individuals was significantly decreased,suggesting that the virus inhibited diet consumption of S.frugiperda via the down-regulation of digestive enzyme activities.These results indicate that a virus initially isolated in a predatory natural enemy can decrease the fitness of its prey species.The virus was found to impact the host proteasome and phagosome pathways related to protein degradation and immunity,providing a potential mechanism to enhance controlling efficiency.
基金Anhui Provincial Health Research Project,No.AHWJ2022c036.
文摘BACKGROUND Colorectal cancer(CRC)is one very usual tumor together with higher death rate.Ubiquitin-specific protease 21(USP21)has been confirmed to take part into the regulation of CRC progression through serving as a facilitator.Interestingly,the promotive function of USP21 has also discovered in the progression of CRC.ZEB1 has illustrated to be modulated by USP7,USP22 and USP51 in cancers.However,the regulatory functions of USP21 on ZEB1 in CRC progression need more invest-igations.AIM To investigate the relationship between USP21 and ZEB1 in CRC progression.METHODS The mRNA and protein expressions were assessed through RT-qPCR,western blot and IHC assay.The interaction between USP21 and ZEB1 was evaluated through Co-IP and GST pull down assays.The cell proliferation was detected through colony formation assay.The cell migration and invasion abilities were determined through Transwell assay.The stemness was tested through sphere formation assay.The tumor growth was evaluated through in vivo mice assay.RESULTS In this work,USP21 and ZEB1 exhibited higher expression in CRC,and resulted into poor prognosis.Moreover,the interaction between USP21 and ZEB1 was further investigated.It was demonstrated that USP21 contributed to the stability of ZEB1 through modulating ubiquitination level.In addition,USP21 streng-thened cell proliferation,migration and stemness through regulating ZEB1.At last,through in vivo assays,it was illustrated that USP21/ZEB1 axis aggravated tumor growth.CONCLUSION For the first time,these above findings manifested that USP21 promoted tumorigenicity and stemness of CRC by deubiquitinating and stabilizing ZEB1.This discovery suggested that USP21/ZEB1 axis may provide novel sights for the treatment of CRC.
基金financially supported by the National Natural Science Foundation of China(32001728,32172248)the Taishan Industrial Experts Program+1 种基金the Guizhou High-level Innovative Talent Training Project(Qianke Cooperation Platform Talent number[2016]5662)Guizhou Science and Technology Innovation Talent Team of Ecological Characteristic Meat Products.(QKHPTRC[2020]5004)。
文摘Dry-cured meat products are considerably popular around the world due to unique flavor.Proteolysis is one of the enzymatic reactions from which flavor substances are derived,which is affected by endogenous proteases.The purpose aimed to reveal the potential relationship between endogenous proteases and key flavor substances in dry-cured pork coppa in this paper.The dynamic changes of endogenous proteases activity,free amino acids,and volatiles during dry-cured pork coppa processing were characterized.The results showed that 5 kinds of free amino acids,Glu,Lys,Val,Ala,and Leu,were identified as significant contributors to taste.Meanwhile,key volatiles,such as hexanal,nonanal,octanal,benzaldehyde,3-methyl butanoic acid,2-methyl propanoic acid,and ethyl octanoate,greatly contributed to the flavor characteristics of dry-cured pork coppa.Further partial correlation analysis was performed to better elucidate the relationship among parameters.The results revealed that close relationship between endogenous proteases and key substances.RAP not only significantly affected the accumulation of key active-amino acids,but also affected the accumulation of ethyl octanoate,2,3-pentanedione,and 2,3-octanedione by regulating the accumulation of octanoic acid and Leu.In addition,cathepsin B and D,DPP II,DPP IV and RAP notably affected accumulation of hexanal.
基金National Institutes of Health(NIH)(grants R01 A/130092 and Al161085).
文摘The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1 contains the receptor-binding domain(RBD),while the S2 contains the hydrophobic fusion domain for the entry into the host cell.Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various c leavage sites.In this article,we review host proteases including furin,trypsin,transmembrane protease serine 2(TMPRSS2)and cathepsins in the activation of SARS-CoV-2 S.Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin.The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2,and the binding triggers further conformational changes and exposure of the S2'site to proteases such as type Il transmembrane serine proteases(TTPRs)including TMPRSS2.In the presence of TMPRSS2 on the target cells,SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane.In the absence of TMPRSS2,SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry.Additional host proteases involved in the cleavage of the S were discussed.This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2,and discussed the dual roles of such inhibitors in virus replication.
文摘BACKGROUND Recent advancements in biliary tract cancer(BTC)treatment have expanded beyond surgery to include adjuvant therapy,yet the prognosis remains poor.Identifying prognostic biomarkers could enhance the assessment of patients who have undergone radical resection for BTC.AIM To determine transmembrane serine protease 4(TMPRSS4)utility as a prognostic biomarker of radical resection for BTC.METHODS Medical records of patients who underwent radical resection for BTC,excluding intrahepatic cholangiocarcinoma,were retrospectively reviewed.The associations between TMPRSS4 expression and clinicopathological factors,overall survival,and recurrence-free survival were analyzed.RESULTS Among the 85 patients undergoing radical resection for BTC,46(54%)were TMPRSS4-positive.The TMPRSS4-positive group exhibited significantly higher preoperative carbohydrate antigen 19-9(CA19-9)values and greater lymphatic invasion than the TMPRSS4-negative group(P=0.019 and 0.039,respectively).Postoperative overall survival and recurrence-free survival were significantly worse in the TMPRSS4-positive group(median survival time:25.3 months vs not reached,P<0.001;median survival time:28.7 months vs not reached,P=0.043,respectively).Multivariate overall survival analysis indicated TMPRSS4 positivity,pT3/T4,and resection status R1 were independently associated with poor prognosis(P=0.032,0.035 and 0.030,respectively).TMPRSS4 positivity correlated with preoperative CA19-9 values≥37 U/mL and pathological tumor size≥30 mm(P=0.016 and 0.038,respectively).CONCLUSION TMPRSS4 is a potential prognostic biomarker of radical resection for BTC.
基金We thank Prof.Liang Chen for insightful input and valuable scientific suggestions,Prof.Dr Xinchao Wang,Lu Wang and Yuchun Wang for kindly supplying experimental materials,Xiwang Li and Jianying Jin for looking after the insects and plants.This research was supported by National Natural Science Foundation of China(31272053,31901898)Central Public-interest Scientific Institution Basal Research Fund(Y2023PT03,1610212019001)the Elite Youth Program of Chinese Academy of Agricultural Sciences for Meng Ye.
文摘Protease inhibitors promote herbivore resistance in diverse plant species.Although many inducible protease inhibitors have been identified,there are limited reports available on the biological relevance and molecular basis of constitutive protease inhibitors in herbivore resistance.Here,we identified a serine protease inhibitor,CsSERPIN1,from the tea plant(Camellia sinensis).Expression of CsSERPIN1 was not strongly affected by the assessed biotic and abiotic stresses.In vitro and in vivo experiments showed that CsSERPIN1 strongly inhibited the activities of digestive protease activities of trypsin and chymotrypsin.Transient or heterologous expression of CsSERPIN1 significantly reduced herbivory by two destructive herbivores,the tea geometrid and fall armyworm,in tea and Arabidopsis plants,respectively.The expression of CsSERPIN1 in Arabidopsis did not negatively influence the growth of the plants under the measured parameters.Our findings suggest that CsSERPIN1 can inactivate gut digestive proteases and suppress the growth and development of herbivores,making it a promising candidate for pest prevention in agriculture.
基金This research was supported by the National Key Research and Development Program of China(2021YFD1800403)the National Natural Science Foundation of China(32273005 and 32002256).
文摘The serine proteases of Mycobacteria tuberculosis(Mtb)are important contributors to the process of bacterial invasion and its pathogenesis.In the present study,we systematically characterized the role of the Rv1043c protein in Mycobacterium infection by purifying the Rv1043c protein in Escherichia coli and constructing a Mycobacterium smegmatis(Msg)strain overexpressing Rv1043c(Msg_Rv1043c).We found that Rv1043c had serine protease activity and localized to the surface of Mtb.We determined that the optimal pH and temperature for the Rv1043c serine protease were 9.0 and 45°C,respectively.Moreover,the serine protease activity of Rv1043c was enhanced by divalent metal ions of Ca^(2+)and Mg^(2+).Site-directed mutagenesis studies demonstrated that the serine 279 residue in Rv1043c plays a catalytic role.Additionally,mouse model studies confirmed that Rv1043c significantly enhanced the survival of Msg in vivo,induced pulmonary injury and lung cell apoptosis,and promoted the release of pro-inflammatory cytokines interleukin-1βand interleukin-6 in mice.This study presents novel insights into the relationship between mycobacterial serine protease and the pathogenesis of the disease.
基金This work was supported by the National Key R&D Program of China(2022YFD1400500)the China Agriculture Research System of MOF and MARA(CARS-34-07)+1 种基金the Publicinterest Scientific Institution Basal Research Fund,China(Y2022GH12)the Central Public-interest Scientific Institution Basal Research Fund,China(S2021XM22 and S2022XM21)。
文摘Female adults of the migratory locust,Locusta migratoria manilensis(Meyen),can sense seasonal photoperiod changes,which induces embryonic diapause as a key strategy to overwinter.Serine protease inhibitor genes(SPNs)were thought to play key roles during diapause,while few SPNs were functionally characterized.LmSPN2 was one of those genes differentially expressed between diapause and non-diapause eggs;however,its biological function remained to be explored.So,we conducted RNAi knockdown of LmSPN2,resulting in a significant decrease of the egg diapause rate by 29.7%.Using yeast two-hybrid assays,co-immunoprecipitation,and pull-down methods,we found an interaction between LmSPN2 and LmSPN3,which was proved to be mediated by a glutamate(E331)binding site of LmSPN2.RNAi knockdown of LmSPN3 resulted in a significant increase in diapause rate by 14.6%,indicating an inverse function of LmSPN2 and LmSPN3 on diapause regulation.Double knockdown of two SPN genes resulted in a 26.4%reduction in diapause rate,indicating that LmSPN2 was the dominant regulatory signal.Moreover,we found four Toll pathway genes(easter,spätzle,pelle,and dorsal)upregulated significantly after the knockdown of LmSPN2 while downregulated after the knockdown of LmSPN3.Therefore,we speculate that two SPNs regulate diapause through the Toll pathway.Our results indicated that LmSPN2 positively regulates locust egg entry into diapause,while LmSPN3 is a negative regulator of embryonic commitment to diapause.Their interaction is mediated by the binding site of E331 and influences egg diapause through the Toll pathway.This mechanistic understanding of diapause regulation expands our understanding of insect developmental regulation and provides functional targets for developing locust management strategies.
基金supported by China Agriculture Research System of MOF and MARA,CARS-46。
文摘In this study, a gene encoding serine protease(PmSpr288)from cold-adapted bacterium, namely Planococcus maritimus XJ11, was cloned and overexpressed in Escherichia coli BL21(DE3). Bioinformatics analysis revealed that PmSpr288 belongs to serine protease S8 superfamily with a classical catalytic triad comprised by the Asp49, His86 and Ser251. Moreover, PmSpr288 was found to be active over broad alkaline pH and low-moderate temperature, and exhibited wide range of protein substrate specificity. In addition, PmSpr288 was able to hydrolyze the meat proteins actin and myosin, and molecular docking results suggested that the crucial interaction between PmSpr288 and actin/myosin complexes was mainly occupied by hydrogen bonds. The muscle protein hydrolysates of silver carp prepared by PmSpr288 was shown to have antioxidant activity via DPPH radical scavenging assay, which presented an IC_(50) valve of 1.309 mg/mL. In conclusion, these characteristics imply that PmSpr288 has potential biotechnological application prospect for the production of bioactive peptides.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR202102270334)the National Key Research and Development Program of China(No.2020YFD0901004).
文摘Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃and pH 7.0,and a desir-able extraction efficiency was achieved by using the crude collagenolytic protease.Dynamic light scattering,transmission electron microscopy and energy-dispersive X-ray analysis revealed that nano-HA are anionic spherical(about 110nm)particles mainly com-prised of calcium and phosphorus at an approximate ratio of 5:3.As evaluated with the mouse ex vivo intestinal segments,the extracted nano-HA displayed comparable level of intestinal bioavailability to the positive control CaCl_(2).By treating with inhibitors(NaN3,ami-loride)and low temperature(4℃),clathrin-mediated endocytosis was assumed to involve the intestinal absorption of nano-HA.Over-all,the application of thermostable collagenolytic protease is proved to be a promising alternative method for nano-HA extraction from natural resource with improved ecological and biological value.
基金supported by the Science and Technology Mission Project of Liaoning Province Science and Technology Council(2021JH5/10400016)the Service Local Project of Liaoning Provincial Committee of Education(LSNFW202002)the Science and Technology Mission Project of Shenyang Science and Technology Council(20-207-3-25)。
文摘Potato protease inhibitors(PPIs),as the main component of potato protein isolate,have good safety,nutrition and great market potential.The antioxidant and anticancer properties of PPIs were evaluated with cellbased biological assays.The results showed that when the concentration of PPIs was 5 mg/mL,the peroxyl radical scavenging value was(2119±204)mg VCE/100 g,and the cellular antioxidant activity values were(45.83±3.5)(no PBS wash)and(33.25±4.4)μmol QE/100 g(PBS wash).Cells pretreated with PPIs could significantly prevent the oxidative damage induced by H_(2)O_(2),inhibit the morphological changes of cells and maintain the integrity.Furthermore,PPIs had selective anti-proliferative effects on GIST882 cells(IC50=(10.53±3.87)mg/mL)and demonstrated potent inhibition of the growth,migration and invasion of cancer cells.These findings provide a scientific basis for PPIs as promising candidates for functional foods to aid in the prevention of oxidative damage and cancer.
文摘One of plant-based products for dental care is plant-based proteolytic enzymes which are principally proteases. In order not to damage the protein and bioactive content, an efficient method should be employed for their purifications. As such, three-phase partitioning (TPP) was used to purify protease from moringa (Moringa oleifera). TPP is an emerging, promising, non-chromatographic and economical technology which is simple, quick, efficient and often one-step process for the separation and purification of bioactive molecules from natural sources. It involves the addition of salt (ammonium sulphate) to the crude extract followed by the addition of an organic solvent (butanol). The protein appears as an interfacial precipitate between upper organic solvent and lower aqueous phases. The various conditions such as ammonium sulphate, ratio of crude extract to t-butanol and pH which are required for attaining efficient purification of the protease fractions were optimized. Under optimized conditions, it was seen that, 35% of ammonium sulphate saturation with 1:0.75 ratio of crude extract to t-butanol at pH 7 gave 4.94-fold purification with 96.20% activity yield of protease in the middle phase of the TPP system. The purified enzyme from Moringa oleifera has no antimicrobial effect on the pathogenic bacteria tested. However, this purified enzyme, can be considered as a promising agent, cheap, and safe source which is suitable for using in various industries.
文摘The gastrointestinal barrier is-with approximately 400 m^2-the human body's largest surface separating the external environment from the internal milieu. This barrier serves a dual function: permitting the absorption of nutrients, water and electrolytes on the one hand, while limiting host contact with noxious luminal antigens on the other hand. To maintain this selective barrier, junction protein complexes seal the intercellular space between adjacent epithelial cells and regulate the paracellular transport. Increased intestinal permeability is associated with and suggested as a player in the pathophysiology of various gastrointestinal and extraintestinal diseases such as inflammatory bowel disease, celiac disease and type 1 diabetes. The gastrointestinal tract is exposed to high levels of endogenous and exogenous proteases, both in the lumen and in the mucosa. There is increasing evidence to suggest that a dysregulation of the protease/antiprotease balance in the gut contributes to epithelial damage and increased permeability. Excessive proteolysis leads to direct cleavage of intercellular junction proteins, or to opening of the junction proteins via activation of protease activated receptors. In addition, proteases regulate the activity and availability of cytokines and growth factors, which are also known modulators of intestinal permeability. This review aims at outlining the mechanisms by which proteases alter the intestinal permeability. More knowledge on the role of proteases in mucosal homeostasis and gastrointestinal barrier function will definitely contribute to the identification of new therapeutic targets for permeability-related diseases.
基金The AoShan Talents Cultivation Program supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2017ASTCP-OS14the National Natural Science Foundation of China under contract Nos 31670063,31670497 and 31870052+1 种基金the Taishan Scholars Program of Shandong Province under contract No.2009TS079the Science and Technology Basic Resources Investigation Program of China under contract No.2017FY100804
文摘Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened protease-producing bacteria from the South China Sea sediments and analyzed the diversity of their extracellular proteases at the family level through N-terminal amino acid sequencing. Results of the 16 S rRNA gene sequence analysis showed that all screened protease-producing bacteria belonged to the class Gammaproteobacteria and most of them were affiliated with different genera within the orders Alteromonadales and Vibrionales. The Nterminal amino acid sequence analysis for fourteen extracellular proteases from fourteen screened bacterial strains revealed that all these proteases belonged to the M4 family of metalloproteases or the S8 family of serine proteases. This study presents new details on taxa of marine sedimentary protease-producing bacteria and types of their extracellular proteases, which will help to comprehensively understand the process and mechanism of the microbial enzymatic degradation of marine sedimentary organic nitrogen.
文摘Snake venoms,especially those from the two subfamilies,Crotalinae and Viperinae,contained a lot of serine proteases. They were responsible for the hemorrhage,shock,or disorder of blood coagulation after envenomation. They acted,by activating,inactivating,or other converting effects,on almost all the components of hemostatic and fibrinolytic systems. Their sequences were homologous to trypsin-kallikrein serine proteases. Variation of primary sequences out of active center results in the difference of substrate specificities and the further difference of biological and pharmacological activities. Because of their common and unique properties compared to their physiological corresponding factors,snake venom proteases are proved to be an excellent model for the study of protease substrate discriminating mechanism. Furthermore,they have found an important position both in basic research and application of hemostasis and thrombosis in clinic.
基金Supported by National Natural Science Foundation of China(30460016)Science and Technology Plan from Yunnan Branch Office of China National Tobacco Corporation(2011YN03,2010YN03,07A01)~~
文摘[Objective] The study aimed to investigate the activity and gene expression of caspase-like proteases in tobacco leaves growing under different light qualities. [Method] By covering tobacco plants with white, red, yellow, blue and purple films to obtain different light quality, the changes of chlorophyll content, activity and gene expression of caspase-like proteases in the tobacco leaves were studied. [Results] Compared with treatments of white, red and yellow film, blue and purple films delayed the decrease of chlorophyll content and senescence of tobacco leaves at the late growth stage, and relatively lowered the activity and gene expression of caspase-like proteases during growth, development and senescence periods. [Conclusion] Different light qualities exhibited various effects on the growth, development and senescence of tobacco leaves, possibly by affecting the activity and gene expression of caspase-like proteases to some extent.
基金Supported by University Research Fund Doctoral Projects(BOF-DOCPRO),No.DOCPRO4 2014/ID 2964Research Foundation Flanders(FWO),No.G034113N
文摘Proteases, enzymes catalyzing the hydrolysis of peptide bonds, are present at high concentrations in the gastrointestinal tract. Besides their well-known role in the digestive process, they also function as signaling molecules through the activation of protease-activated receptors(PARs). Based on their chemical mechanism for catalysis, proteases can be classified into several classes: serine, cysteine, aspartic, metallo- and threonine proteases represent the mammalian protease families. In particular, the class of serine proteases will play a significant role in this review. In the last decades, proteases have been suggested to play a key role in the pathogenesis of visceral hypersensitivity, which is a major factor contributing to abdominal pain in patients with inflammatory bowel diseases and/or irritable bowel syndrome. So far, only a few preclinical animal studies have investigated the effect of protease inhibitors specifically on visceral sensitivity while their effect on inflammation is described in more detail. In our accompanying review we describe their effect on gastrointestinal permeability. On account of their promising results in the field of visceral hypersensitivity, further research is warranted. The aim of this review is to give an overview on the concept of visceral hypersensitivity as well as on the physiological and pathophysiological functions of proteases herein.
文摘[Objective] The aim of the study is to construct cDNA library of midgut tissue of wild silkworm and isolate the serine protease gene. [Method] The midgut tissue-specific cDNA library of wild silkworm was constructed via cDNA Library Construction Kit (TaKaRa), then the serine protease gene was cloned via sequencing of the yielded cDNA library. [Result] The titer of cDNA library reached 6.2×105 pfu/ml, average insert size was about 1.2 kb. The serine protease gene cDNA fragment was obtained from colony sequencing (Accession No: EU672968). The nucleotide sequence of the cloned 854 bp fragment encodes 284 amino acid residues. Homology analyses showed some homology between putative amino acid sequence of the cloned fragment and amino acid sequences of serine proteases from other ten insects. [Conclusion] The results may avail to reveal the resistance of silkworm and wild silkworm to exotic intrusion.
基金Supported by High Academic Youth Backbone Support Projects in Heilongjiang Province(1152G022)Scientific Research Foundation for Doctor in Heilongjiang August First Land Reclamation University~~
文摘[Objective] The aim of the study was to provide the basis for researching the pathogenicity mechanism of Rhizoctonia solani.[Method] The extracellular protease was purified after ammonium sulfate precipitation through DEAE-Sephrase Fast Flow,Phenyl-Sepharose Fast Flow and Sephadex G-75 ch rom atography. [Result] The extracellular protease with molecular weight of 49.5 ku was obtained from fermentation liquid of R. solani. The optimal temperature and pH value for its activity were 6.4 and 30 ℃ respectively. Zn^2＋,Fe^3＋,Cu^2＋had inhibition on enzyme activity,while Mg^2＋,Mn^2＋had no effect on enzyme activity,and Ca^2＋ could activate enzymatic activity in low concentration.[Conclusion] R. solani could secrete extracellular protease,but the relationship between the extracellular protease and the pathogenicity of R. solani required further study.
文摘[Objective] The aim of this study was to study effects of metal ions on the protease activities in digestive tissues and gland of red-white ornamental carp（Cyprinus carpio L）.[Method] Effects of four kinds of metal ions （K＋,Na＋,Mg2＋ and Ca2＋） on protease activities in hepatopancreas,foregut,midgut,hindgut of red-white ornamental carp were studied by enzyme analysis method.[Result] Effects of four kinds of metal ions on protease activities of red-white ornamental carp were different in the range of experimental concentration from 25 mmol/L to 150 mmol/L.K＋ could promote protease activities in hepatopancreas and hindgut at different levels.Especially,K＋ had the promoting effect at low-concentration level,but the inhibitory effect at high-concentration level in midgut and the inhibitory effect in foregut.Na＋ had the promoting effect on protease activities in hepatopancreas,foregut and hindgut at different levels,but the inhibitory effect in midgut.Mg2＋ and Ca2＋ had the inhibitory effect on protease activities in intestinal and hepatopancreas at different levels.[Conclusion] This study provides basic data and theoretical foundation for researches on the digestive physiology of red-white ornamental carp or the development and optimization of compound feed.
