ABSTRACT
Abstract@#As a new social phenomenon, fragmented sleep breaks through the limitations of time and space, and provides self comfort for teenagers to learn entertainment at night, but the moderation of fragmented sleep must be studied. The paper ellucidates the essence of fragmented sleep, probes into the reasons, and optimizes sleep fragmentation in their school lives in the persepctive of adolescents behaviors and mental health, so as to find out the targeted measures of policy support, family-school cooperation and exercise support.
ABSTRACT
@#The tolerance of microorganism under acid stress is of significant importance to the growth and industrial production of bacterial strain. When the bacterial cells are exposed to the external acid environment, proteins in periplasmic space are under higher acid stress and are thusmore susceptible to severe damage from acid than the intracellular protein, and these are also more susceptible to severe damage from acid than the intracellular protein. During the acid-resisting process of Gram-negative bacteria, in addition to the intracellular decarboxylase system, the molecular chaperone can also participate in the identification and protection of the space structure of protein as an important "correcting" mechanism. This paper, reviews the current researches on the function, structure, acid-resisting mechanism of variousmolecular chaperones, including HdeA, HdeB, DnaK and GroEL. Finally, the research progress of the acid-resisting mechanism among Gram-negative bacteria is summarized. Through in-depth investigation and analysis of the physiological adaptation strategy of molecular chaperone to the acid stress environment, this study can help to conduct physiological property modification of target strain and improve their viability and tolerance in acid stress environment, which has its important theoretical and practical significance.
ABSTRACT
As one important member of B7/CD28/CTLA-4 costimulatory signal pathway, B7-2 molecule plays a critical role in regulating T-cell response. In order to further explore its effects on regulation of T cell activation, proliferation and associated signal pathways, the cDNA encoding extracellular region of human B7-2 was amplified via PCR and subcloned into some prokaryotic expression vectors to express target protein in host strains. The expressed protein was identified with Western blot and MTT. Results showed that after screening, the expression level of the protein of interest attained the yield of over 20% total bacterial protein by using pGEX-4T-2 vector and E. coli BL21 (DE3)-CodonPlus-RIL host cells. The recombinant protein could specially react with B7-2 McAb and could stimulate T-cell proliferation combined with anti-CD3 antibody. In conclusion, the recombinant protein was bioactive, therefore the study will make it possible for the research of relationship between B7-2 structure and its function.