Diversity of the T cell receptor ß chain complementarity-determining region 3 in peripheral blood of neonates with sepsis: an analysis based on immune repertoire sequencing. / å ç–«ç»„åº“æµ‹åºåˆ†æžæ–°ç”Ÿå„¿è„“æ¯’ç—‡æ‚£è€ å¤–å‘¨è¡€T细胞受体ß链CDR3çš„å¤šæ ·æ€§.

OBJECTIVES: To investigate the diversity of peripheral blood T cell receptor (TCR) ß chain complementarity-determining region 3 (CDR3) based on immune repertoire sequencing in neonates with sepsis and the possible pathogenesis of neonatal sepsis. METHODS: A total of 12 neonates with sepsis were enrolled as the case group, and 9 healthy full-term infants, matched for gestational age, birth weight, and age, were enrolled as the control group. Omega nucleic acid purification kit (SQ blood DNA Kit II) was used to extract DNA from peripheral blood samples, TCR ß chain CDR3 was amplified by multiplex PCR, and then high-throughput sequencing was performed for the products to analyze the diversity of TCR ß chain CDR3 and the difference in expression. RESULTS: The length and type of TCR ß chain CDR3 were similar between the case and control groups, and Gaussian distribution was observed in both groups. With D50 and Shannon-Wiener index as the evaluation indices for diversity, the case group had a significantly lower diversity of TCR ß chain CDR3 than the control group (P<0.05). The frequency of 48 genes in TCR ß chain V segment was compared, and the results showed that compared with the control group, the case group had significantly higher frequencies of TRBV10-3, TRBV2, and TRBV20-1 (P<0.05). The frequency of 13 genes in TCR ß chain J segment were compared, and the results showed that compared with the control group, the case group had significantly higher frequencies of TRBJ2-3, TRBJ2-5, and TRBJ2-7 (P<0.05). CONCLUSIONS: There is a significant change in the diversity of TCR ß chain CDR3 in the peripheral blood of neonates with sepsis, suggesting that it might be associated with the immune pathogenesis of neonatal sepsis.

Silver-promoted decarboxylative amidation of α-keto acids with amines.

A general and effective method for the synthesis of amides through decarboxylative amidation of α-keto acids with amines has been developed. The reaction proceeded smoothly to afford the corresponding amide products in good yield under air and shows excellent functional group tolerance. In addition, the protocol can be further applied in the synthesis of heterocyclic compounds like benzimidazoles.

Extracellular metalloproteases from bacteria.

Bacterial extracellular metalloproteases (BEMPs) are a large group of metal-containing proteases secreted by heterotrophic bacteria. In this review, the diversity, structural characteristics, mechanisms of maturation, physiological roles, and applications of BEMPs are described. BEMPs are distributed among nine families of metalloproteases because of differences in primary sequences and structural characteristics. Until now, all of the BEMPs identified have been endoproteases harboring one catalytic Zn(2+) in the active centers. BEMPs are usually synthesized as inactive zymogens with a propeptide that is covalently linked to and inhibits the catalytic domain. The removal of the propeptides of BEMPs is dependent on other proteases or an autocleavage process. The main physiological function of BEMPs is to degrade environmental proteins and peptides for bacterial heterotrophic nutrition. As extracellular proteases, BEMPs vary greatly in enzymology properties to adapt to their respective environments. BEMPs have been widely used in the food and pharmaceutical industries. In order to broaden the application of BEMPs, it is essential to explore novel BEMPs and apply gene/protein engineering to improve the production and properties of promising BEMPs.