1.Discovery of a new nosiheptide-producing strain and its fermentation optimization for nosiheptide production
Qihang SUN ; Yuncong XU ; Lingrui WU ; Jiale RONG ; Yanwen WANG ; Yudan CAO ; Chen LUO ; Xuri WU
Journal of China Pharmaceutical University 2022;53(6):725-733
Nosiheptide is a typical thiopeptide antibiotic displaying potent activity toward various drug-resistant strains of Gram-positive pathogens.Although nosiheptide lacks in vivo activity, and good water-solubility with a series of uncontrollable analogues, which may limit its clinical application, glycosylated analogues may overcome problem of low activity and may improve its druggability.In search of novel glycosylated nosiheptide producers, we applied a genome mining strategy that identified Actinoalloteichus sp.AHMU CJ021 that contains all genes required.However, despite the presence of a predicted glycosyltransferase, glycosylated derivatives of nosiheptide were not detected, after following one strain many compounds (OSMAC) strategy and heterologous expression of a regulatory protein NocP.Nevertheless, nosiheptide produced by this strain was remarkably pure, and further experiments were conducted to improve its production by optimization of the culture medium.Under optimal conditions, 58.73 mg/L nosiheptide was produced, representing an almost 6-fold improvement compared to the original fermentation medium.Therefore, we consider Actinoalloteichus sp.AHMU CJ021 a suitable potential candidate for industrial production of nosiheptide, which provides the basis for solving the problem of nosiheptide structural analogues.
2.The effect of brain aging on the brain′s walking network as revealed by functional near infrared spectroscopy
Hui LU ; Qihang LUO ; Lingxion ZHENG ; Xingshen HUANG ; Haining OU ; Qiang LIN ; Junjie LIANG
Chinese Journal of Physical Medicine and Rehabilitation 2022;44(12):1069-1073
Objective:To explore any effect of brain aging on the brain′s walking network and its mechanism.Methods:Twenty healthy elderly people and 22 healthy young adults formed an elderly group and a youth group. All were evaluated using the Mini-Mental State Examination (MMSE), the Timed Up and Go test (TUGT), the 10-metre walk test (10MWT), the functional near infrared spectroscopy walking synchrony test and GaitRite gait parameters. The intensity of functional connections and the gait parameters of the prefrontal cortex (PFC) and the primary motor cortex (MC) were compared between the two groups.Results:Compared with the youth group, the average cadence of the elderly group was significantly faster. The FC value of the RPFC in the homologous ROI, as well as those of the RMC-RPFC and RPFC-LPFC in the heterologous ROI of the elderly group were significantly lower than in the youth group.Conclusions:Lower FC values in the RPFC and its associated brain regions in the elderly during normal walking may be what activates the brain′s walking network in the early stage of brain aging.
3.Brain network during balance in older adults: a functional near-infrared spectroscopy study
Qihang LUO ; Yuxi WU ; Jiaxuan ZHANG ; Wanying LI ; Haining OU ; Qiang LIN ; Junjie LIANG
Chinese Journal of Rehabilitation Theory and Practice 2023;29(2):238-242
ObjectiveTo study the brain network during balance control tasks in older adults. MethodsFrom January to April, 2022, 22 healthy young adults and 20 healthy older adults were recruited from the Fifth Affiliated Hospital of Guangzhou Medical University and communities. They were asked to finish standing tasks on the plantar pressure plate with eyes opening and closing, while the functional connectivities (FC) of prefrontal cortex (PFC) and primary motor cortex (PMC) were measured with functional near-infrared spectroscopy. ResultsCompared with the young adults, the area of the ellipse (Z = -2.884, P < 0.01) and the maximum swing (Z = -2.481, P < 0.05) increased in the older adults as eyes closing. During the standing task, the intra-FC of left (t = 2.978, P < 0.01) and right (Z = -3.123, P < 0.01) PFC decreased in the older adults, and the inter-FC of right PMC to left PFC (t = 2.087, P < 0.05) and right PFC to left PFC (t = 3.471, P < 0.001) decreased, too. ConclusionThe FC of PFC decreased in healthy older adults during balance control tasks, which may be a indicator for aging brain.