Lactobacillus was selected as a bacterial carrier for expression of N-lobe of porcine lactoferrin （PLFN）. A pair of primers was designed with Oligo6.0 and used to amplify PLFN gene. It was in accordance with the cha...Lactobacillus was selected as a bacterial carrier for expression of N-lobe of porcine lactoferrin （PLFN）. A pair of primers was designed with Oligo6.0 and used to amplify PLFN gene. It was in accordance with the characters of translational fusions from gene and expression vector plasmid. A 1 077 bp fragment of the gene from PLF was cloned from mammary gland tissue of the lactating sow on the third day by RT-PCR; the gene was connected with the vector plasmid pPG612.1 and transformed into the host strain JM109. The recombinant expression vector plasmid pPG612-PLFN was created and identified by using plasmid extraction, PCR, restriction enzyme digestion and sequence analysis. The recombinant plasmid was transformed into Lactobacillus casei ATCC393, Lactobacillus plantarum KLDS 1.0344, Lactobacillus paracasei KLDS 1.0652 and Lactobacillus pentosus KLDS 1.0413 by electroporation, and produced the recombinant strains of pPG612-PLFN/L, casei, pPG612-PLFN/L, plantarum, pPG612-PLFN/ L. paracasei and pPG612-PLFN/L, pentosus, respectively. The results indicated that PLFN gene had inserted into the expression vectors and achieved multiple Laetobacillus expression systems. It electes the base for the expression and production of recombinant porcine lactoferrin in Lactobaeillus展开更多
The fiber laser welding tests for 3 mm thick TC4 titanium alloy plates are carried out,and the microstructures of the joints are analyzed by the OM and SEM,and the mechanical properties of the joints are described by ...The fiber laser welding tests for 3 mm thick TC4 titanium alloy plates are carried out,and the microstructures of the joints are analyzed by the OM and SEM,and the mechanical properties of the joints are described by tensile and hardness tests,and the SEM morpho-logies of the tensile fracture are observed.The results show that the weld zone is composed of columnarβphase with coarse grains and acicular martensiteα',and small secondaryα'phases in different directions are formed acicular martensiteα'.The microstructure at the boundary between the HAZ and the weld is composed ofα'andαphases,the microstructure at the boundary between the HAZ and the base metal is composed of the initial(αandβ)andαphases,and the microstructure of the middle transition zone of the HAZ is composed of a small amount ofα'andαphase of high temperatureβphase’transformation and initial(αandβ)phases.The average tensile strength of TC4 titanium alloy laser beam welded joints is 1056 MPa,and the average elongation is 9.0%,which are lower than the tensile strength and the elongation of the base metal respectively.The fracture is ductile fracture,and the hardness of the weld zone is the highest and that of the HAZ is the lowest.展开更多
基金Supported by National Natural Science Foundation of China (30871809,31072057)Principal Fund of Northeast Agricultural University
文摘Lactobacillus was selected as a bacterial carrier for expression of N-lobe of porcine lactoferrin （PLFN）. A pair of primers was designed with Oligo6.0 and used to amplify PLFN gene. It was in accordance with the characters of translational fusions from gene and expression vector plasmid. A 1 077 bp fragment of the gene from PLF was cloned from mammary gland tissue of the lactating sow on the third day by RT-PCR; the gene was connected with the vector plasmid pPG612.1 and transformed into the host strain JM109. The recombinant expression vector plasmid pPG612-PLFN was created and identified by using plasmid extraction, PCR, restriction enzyme digestion and sequence analysis. The recombinant plasmid was transformed into Lactobacillus casei ATCC393, Lactobacillus plantarum KLDS 1.0344, Lactobacillus paracasei KLDS 1.0652 and Lactobacillus pentosus KLDS 1.0413 by electroporation, and produced the recombinant strains of pPG612-PLFN/L, casei, pPG612-PLFN/L, plantarum, pPG612-PLFN/ L. paracasei and pPG612-PLFN/L, pentosus, respectively. The results indicated that PLFN gene had inserted into the expression vectors and achieved multiple Laetobacillus expression systems. It electes the base for the expression and production of recombinant porcine lactoferrin in Lactobaeillus
基金supported by the Science and Technology Plan Foundation of Guizhou(Guizhou Science Support[2021]General 337)Anhui University Natural Science Key Research Project(2022AH052357).
文摘The fiber laser welding tests for 3 mm thick TC4 titanium alloy plates are carried out,and the microstructures of the joints are analyzed by the OM and SEM,and the mechanical properties of the joints are described by tensile and hardness tests,and the SEM morpho-logies of the tensile fracture are observed.The results show that the weld zone is composed of columnarβphase with coarse grains and acicular martensiteα',and small secondaryα'phases in different directions are formed acicular martensiteα'.The microstructure at the boundary between the HAZ and the weld is composed ofα'andαphases,the microstructure at the boundary between the HAZ and the base metal is composed of the initial(αandβ)andαphases,and the microstructure of the middle transition zone of the HAZ is composed of a small amount ofα'andαphase of high temperatureβphase’transformation and initial(αandβ)phases.The average tensile strength of TC4 titanium alloy laser beam welded joints is 1056 MPa,and the average elongation is 9.0%,which are lower than the tensile strength and the elongation of the base metal respectively.The fracture is ductile fracture,and the hardness of the weld zone is the highest and that of the HAZ is the lowest.
