Indole signaling has been regarded as a promising target to control aquatic diseases.However,the relationship between exogenous indole and the virulence of Edwardsiella piscicida is obscure.E.piscicida is a facultativ...Indole signaling has been regarded as a promising target to control aquatic diseases.However,the relationship between exogenous indole and the virulence of Edwardsiella piscicida is obscure.E.piscicida is a facultative intracellular pathogen,and has been a model strain in aquaculture.In this study,we investigated the effect of exogenous indole on stress resistance and virulence of E.piscicida in the presence of and absence of endogenous indole(WT andΔtnaA,respectively).Our results showed that exogenous indole reduced the resistance of WT against strong acidic stress,but enhanced that ofΔtnaA.Also,we found that exogenous indole abated viability of E.piscicida at high temperature,repressed bacterial biofilm formation,impaired bacterial envelope integrity,and weakened bacterial proliferation in macrophages,irrespective of the presence or absence of endogenous indole.These virulence-related phenotypes caused by exogenous indole are reasonably explained by the observation that exogenous indole downregulated the expressions of CpxRA and its target YccA via being responded by CpxA.The effects of exogenous indole on strong acid resistance are partially achieved by changing the expression of GadD,the key functional enzyme of acid resistance system(AR2).We believe that this is the first report about the impact of exogenous indole on strong acid stress and membrane integrity of pathogenic bacteria.Also,we reveal the likely mechanism by which exogenous indole regulates the expressions of virulence-related genes.These findings provide a new understanding on pathogenesis of E.piscicida and contribute to the prevention and control strategies of edwardsiellosis.展开更多
Mitogen-activated protein kinases(MAPKs)play pivotal roles in response to environmental stresses and bacterial infections.Compared with those in the higher vertebrates,studies of mapk gene family are still limited in ...Mitogen-activated protein kinases(MAPKs)play pivotal roles in response to environmental stresses and bacterial infections.Compared with those in the higher vertebrates,studies of mapk gene family are still limited in teleost.Identification,characterization,classification,and expression profiling of totally 15 mapk genes in black rockfish(Sebastes schlegelii)were conducted.Phylogenetic relationships show that these mapk genes could be divided into extracellular signal-regulated kinase(ERK),c-Jun N-terminal kinase(JNK),and p38 sub-families.In addition,gene structures,syntenic analysis,and selective pressure analysis are performed to confirm their annotations.Results of selective pressure analysis indicate that mapk1,mapk3,mapk7,mapk10,mapk11,and mapk12 underwent significantly-positive selections,while the others genes such as mapk4,mapk6,mapk15,mapk8a,mapk8b,mapk9,mapk13,mapk14a,and mapk14b were under purifying selections.Moreover,results of qRT-PCR indicate that mapk genes in 8 healthy tissues displayed different expression patterns.The expression patterns of several mapk genes including mapk12,mapk13,mapk14a,mapk14b,and mapk15 were significantly changed in mucosal tissues after Edwardsiella piscicida infection.This study demonstrates that mapk genes in black rockfish play vital prevention roles against bacterial infection,which not only helps us understand the structure and function of mapk genes in black rockfish,but also provides a reference to understand the role of mapk genes in teleost immune responses.展开更多
This study aimed to evaluate the supplementation of the probiotic Pseudoalteromonas piscicida 1Ub to the biofloc system as an ecofriendly strategy for protecting white shrimp(Penaeus vannamei)from Vibrio parahaemolyti...This study aimed to evaluate the supplementation of the probiotic Pseudoalteromonas piscicida 1Ub to the biofloc system as an ecofriendly strategy for protecting white shrimp(Penaeus vannamei)from Vibrio parahaemolyticus infection.Shrimp with an average body weight of(0.50±0.09)g were reared in 30 glass jars with a working volume of 2.5 L at a density of 20 ind/L.Shrimp were reared for 5 d for each treatment,which included the biofloc system without and with 106 colony forming unit(CFU)per mL probiotic.The regular clear water system was used as control.All treatment groups were challenged with 103,105,and 107 CFU/mL V.parahaemolyticus.For the negative control,shrimp were reared without V.parahaemolyticus.The results showed that the density of V.parahaemolyticus cocultured with P.piscicida 1Ub decreased and the density of V.parahaemolyticus in rearing water and shrimp body in the probiotic-treated group was lower than that in the control group(P<0.05).The survival and immune response(total hemocyte count,phagocytic activity,respiratory burst,phenoloxidase,and superoxide dismutase)of shrimp in the probiotic group was higher than that in the positive control(P<0.05).Moreover,supplementing the biofloc system with the probiotic could protect shrimp hepatopancreas from damage caused by V.parahaemolyticus,regardless of bacterial density.Thus,the supplementation of the probiotic P.piscicida 1Ub in the biofloc system could significantly protect and increase the resistance of shrimp to V.parahaemolyticus infection.展开更多
基金supported by the National Natural Science Foundation of China(32273184)Innovational Fund for Scientific and Technological Personnel of Hainan Province(KJRC2023C34)+2 种基金Hainan Province Science and Technology Special Fund(ZDYF2022XDNY246)Zhanjiang Science and Technology Project(2022A01050)the Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences(1630052024019).
文摘Indole signaling has been regarded as a promising target to control aquatic diseases.However,the relationship between exogenous indole and the virulence of Edwardsiella piscicida is obscure.E.piscicida is a facultative intracellular pathogen,and has been a model strain in aquaculture.In this study,we investigated the effect of exogenous indole on stress resistance and virulence of E.piscicida in the presence of and absence of endogenous indole(WT andΔtnaA,respectively).Our results showed that exogenous indole reduced the resistance of WT against strong acidic stress,but enhanced that ofΔtnaA.Also,we found that exogenous indole abated viability of E.piscicida at high temperature,repressed bacterial biofilm formation,impaired bacterial envelope integrity,and weakened bacterial proliferation in macrophages,irrespective of the presence or absence of endogenous indole.These virulence-related phenotypes caused by exogenous indole are reasonably explained by the observation that exogenous indole downregulated the expressions of CpxRA and its target YccA via being responded by CpxA.The effects of exogenous indole on strong acid resistance are partially achieved by changing the expression of GadD,the key functional enzyme of acid resistance system(AR2).We believe that this is the first report about the impact of exogenous indole on strong acid stress and membrane integrity of pathogenic bacteria.Also,we reveal the likely mechanism by which exogenous indole regulates the expressions of virulence-related genes.These findings provide a new understanding on pathogenesis of E.piscicida and contribute to the prevention and control strategies of edwardsiellosis.
基金Supported by the National Key R&D Program of China(No.2018YFD0900101)the Young Experts of Taishan Scholars(No.tsqn201909130)+2 种基金the Science and Technology Support Plan for Youth Innovation of Colleges and Universities in Shandong Province(No.2019KJF003)the“First Class Fishery Discipline”Program in Shandong Provincethe Shandong Technical System of Fish Industry(No.SDAIT-12-03)。
文摘Mitogen-activated protein kinases(MAPKs)play pivotal roles in response to environmental stresses and bacterial infections.Compared with those in the higher vertebrates,studies of mapk gene family are still limited in teleost.Identification,characterization,classification,and expression profiling of totally 15 mapk genes in black rockfish(Sebastes schlegelii)were conducted.Phylogenetic relationships show that these mapk genes could be divided into extracellular signal-regulated kinase(ERK),c-Jun N-terminal kinase(JNK),and p38 sub-families.In addition,gene structures,syntenic analysis,and selective pressure analysis are performed to confirm their annotations.Results of selective pressure analysis indicate that mapk1,mapk3,mapk7,mapk10,mapk11,and mapk12 underwent significantly-positive selections,while the others genes such as mapk4,mapk6,mapk15,mapk8a,mapk8b,mapk9,mapk13,mapk14a,and mapk14b were under purifying selections.Moreover,results of qRT-PCR indicate that mapk genes in 8 healthy tissues displayed different expression patterns.The expression patterns of several mapk genes including mapk12,mapk13,mapk14a,mapk14b,and mapk15 were significantly changed in mucosal tissues after Edwardsiella piscicida infection.This study demonstrates that mapk genes in black rockfish play vital prevention roles against bacterial infection,which not only helps us understand the structure and function of mapk genes in black rockfish,but also provides a reference to understand the role of mapk genes in teleost immune responses.
基金financially supported by the Ministry of Education,Culture,Research,and Technology of the Republic of Indonesia for funding the present study in the form of the Pendidikan Magister menuju Doktor untuk Sarjana Unggul(PMDSU)program scholarship(Grant number:200/SP2H/PMDSU/DRPM/2020).
文摘This study aimed to evaluate the supplementation of the probiotic Pseudoalteromonas piscicida 1Ub to the biofloc system as an ecofriendly strategy for protecting white shrimp(Penaeus vannamei)from Vibrio parahaemolyticus infection.Shrimp with an average body weight of(0.50±0.09)g were reared in 30 glass jars with a working volume of 2.5 L at a density of 20 ind/L.Shrimp were reared for 5 d for each treatment,which included the biofloc system without and with 106 colony forming unit(CFU)per mL probiotic.The regular clear water system was used as control.All treatment groups were challenged with 103,105,and 107 CFU/mL V.parahaemolyticus.For the negative control,shrimp were reared without V.parahaemolyticus.The results showed that the density of V.parahaemolyticus cocultured with P.piscicida 1Ub decreased and the density of V.parahaemolyticus in rearing water and shrimp body in the probiotic-treated group was lower than that in the control group(P<0.05).The survival and immune response(total hemocyte count,phagocytic activity,respiratory burst,phenoloxidase,and superoxide dismutase)of shrimp in the probiotic group was higher than that in the positive control(P<0.05).Moreover,supplementing the biofloc system with the probiotic could protect shrimp hepatopancreas from damage caused by V.parahaemolyticus,regardless of bacterial density.Thus,the supplementation of the probiotic P.piscicida 1Ub in the biofloc system could significantly protect and increase the resistance of shrimp to V.parahaemolyticus infection.
