基于全基因组测序的耐碳青霉烯类抗生素鲍曼不动杆菌耐药基因、毒力因子及同源性分析

摘要：目的 通过应用全基因组测序(whole genome sequencing, WGS)技术分析某三级医疗机构耐碳青霉烯类抗生素鲍曼不 动杆菌(carbapenem-resistant Acinetobacter baumannii, CRAB)的耐药基因、毒力因子及同源性。方法 收集该院2020年1月至3月 重症监护病房(Intensive care unit, ICU)、神经外科分离的11株医院感染CRAB菌株，通过二代测序平台进行全基因组测序, 应用 基因组流行病学中心(Center for genomic epidemiology, CGE)ResFinder 4. 0软件分析其耐药基因型，并应用MORPHEUS在线制作 热图，应用毒力因子数据库(virulence factors of pathogenic bacteria, VFDB)VFanalyzer软件筛选毒力因子，应用MLST软件检测菌 株的ST型，应用Kaptive软件检测荚膜型，应用CSI Phylogeny 1. 4软件及FigTree v1. 4. 4软件构建最大似然树(maximum likelihood tree, MLT)以分析其同源性。结果 11株CRAB对亚胺培南、美罗培南、头孢菌素、环丙沙星均呈现耐药，而对阿米卡星、左氧 氟沙星耐药的菌株株数较少。11株CRAB共检测出18种耐药基因，11株同时携带碳青霉烯酶耐药基因blaOXA-23和blaOXA-66，β-内酰 胺酶耐药基因以blaTEM-1D和blaADC-25为主，大部分菌株携带多种外排泵相关耐药基因及抗菌药物修饰酶耐药基因。11株CRAB均携 带多种毒力因子，包括外膜孔蛋白、脂多糖、生物膜、外排泵、磷脂酶和效应蛋白等，如OmpA、Lps、Csu、Pga、Ade、Plc、 Bas、Bau、Ent、Hem、Aba、Bfm、Pbp和Kat等。11株CRAB均为ST2-K22型，同源性分析结果显示C组内同源性关系相近，存 在院内传播的可能。结论 该院CRAB的耐药性、毒力特征复杂多样，同源性分析显示该院存在1种优势克隆株，该克隆株有医 院内传播的风险。     

Efficient polymer nanoparticle-mediated delivery of gene editing reagents into human hematopoietic stem and progenitor cells

1. Download : Download high-res image (179KB)
2. Download : Download full-size image

     

Memory related molecular signatures: The pivots for memory consolidation and Alzheimer's related memory decline

Age-related cognitive decline is the major cause of concern due to its 70% more incidence than dementia cases worldwide. Moreover, aging is also the major risk factor of Alzheimer's disease (AD), associated with progressive memory loss. Approx. 13 million people will have Alzheimer-related memory decline by 2050. Learning and memory is the fundamental process of brain functions. However, the mechanism for the same is still under investigation. Thus, it is critical to understand the process of memory consolidation in the brain and extrapolate its understanding to the memory decline mechanism. Research on learning and memory has identified several molecular signatures such as Protein kinase M zeta (PKMζ), Calcium/calmodulin-dependent protein kinase II (CaMKII), Brain-derived neurotrophic factor (BDNF), cAMP-response element binding protein (CREB) and Activity-regulated cytoskeleton-associated protein (Arc) crucial for the maintenance and stabilization of long-term memory in the brain. Interestingly, memory decline in AD has also been linked to the abnormality in expressing these memory-related molecular signatures. Hence, in the present consolidated review, we explored the role of these memory-related molecular signatures in long-term memory consolidation. Additionally, the effect of amyloid-beta toxicity on these molecular signatures is discussed in detail.     

p53基因突变与骨髓增殖性肿瘤临床特征及预后关系

探究p53 基因突变与骨髓增殖性肿瘤（MPN）临床特征及预后的关系。方法 选取2017年1月～2020年1月本院收治的MPN患者126例，二代测序法检测患者p53 基因突变情况。对患者进行随访，统计患者总生存（OS）时间和累计生存率；分析p53 基因突变对患者临床特征、预后的影响。结果 126例MPN患者中12例（9.52%）检出p53基因突变，突变主要位于4~8号外显子上，不同类型患者的p53 基因突变检出率比较差异无统计学意义（P＞0.05）。p53突变组患者年龄大于p53 非突变组，WBC水平低于p53 非突变组（P＜0.05），两组患者的染色体核型、IPSS预后分层比较差异无统计学意义（P＞0.05）；p53 非突变组患者的OS时间、累计生存率均明显高于p53突变组患者（P＜0.05）。结论 MPN患者p53 基因突变发生率较高，与患者年龄、WBC水平、异常核型及IPSS预后分层相关，p53 基因突变会影响患者的预后，可作为临床筛查预后不良高风险人群的客观指标。     

我国弓形虫Chinese 1优势基因型感染对小鼠脑组织铁代谢影响

目的　探讨我国弓形虫Chinese 1优势基因型感染对宿主脑组织铁代谢及脑损伤的影响。方法　将20只C57BL/6（体质量15～17 g）小鼠随机分为对照组和感染组，每组10只。感染组每只小鼠腹腔注射4 000个弓形虫Chinese 1优势基因型TgCtwh3虫株速殖子，对照组小鼠注射等量无菌PBS，饲养6 d后处死小鼠并取其脑组织。采用电感耦合等离子体质谱法（inductively coupled plasma mass spectrometry, ICP⁃MS）检测小鼠脑组织铁元素水平；采用RNA芯片检测两组小鼠脑组织差异基因数目并对功能基因表达情况进行基因本体论（Gene Ontology, GO）功能富集；采用实时荧光定量PCR（fluorescent quantitative real⁃time PCR, qPCR）技术检测小鼠脑组织中弓形虫表面抗原1（Toxoplasma gondii surface antigen 1，TgSAG1）基因及部分锌铁调控蛋白（Zrt⁃ and Irt⁃like protein, ZIP）家族mRNA表达水平；采用光镜和电镜观察小鼠脑组织海马齿轮回（dentate gyrus, DG）超微结构；采用Western blotting检测谷胱甘肽过氧化物酶4（glutathione peroxidase 4, GPx4）蛋白表达水平；采用硫代巴比妥酸（TBA）法检测丙二醛（malondialdehyde, MDA）水平；采用免疫组化检测血管内皮生长因子（vascular endothelial growth factor, VEGF）蛋白表达光密度（optical density, OD）值。结果　光镜下可见感染组小鼠脑组织海马DG区细胞坏死，电镜下见感染组小鼠脑组织海马区出现胞质空泡化、核皱缩坏死、线粒体嵴断裂消融、自噬小体增加等超微结构变化。与对照组相比，感染组小鼠脑组织中铁元素水平上调[（32.92 ± 0.90） µg/g vs.（37.72 ± 1.10） µg/g；t = 3.397, P < 0.01]；RNA芯片检测感染组小鼠脑组织发现721个基因上调、276个基因下调，差异表达基因在金属离子结合能力上有明显富集。与对照组相比，感染组小鼠脑组织金属元素转运体ZIP2 mRNA表达水平上调（t = 8.659，P < 0.05）、GPx4表达下降[（1.046 ± 0.025） vs. （0.720 ± 0.101）；t = 3.129，P < 0.01]）、MDA水平升高[（4.37 ± 0.33） nmol/mgprot vs.（5.93 ± 0.54） nmol/mgprot；t = 2.451，P < 0.05）]、VEGF蛋白平均OD值上调[（0.348 3 ± 0.017 8） vs. （0.490 6 ± 0.010 5）；t = 6.641，P < 0.01]。结论　Chinese 1优势基因型弓形虫感染后，小鼠脑组织中铁元素蓄积、抗氧化能力下调、氧化应激水平升高，提示弓形虫感染可影响宿主脑组织铁代谢而导致脑损伤。     

The matricellular protein SPARC induces inflammatory interferon-response in macrophages during aging

1. Download : Download high-res image (179KB)
2. Download : Download full-size image

     

Left ventricular noncompaction associated with a pathogenic mutation in the MYH7 gene: Known mutation,different phenotype

Left ventricular noncompaction (LVNC) is a genetically heterogeneous cardiomyopathy, with familial and sporadic forms, but genetic testing only identifies a pathogenic mutation in a minority of cases. The main complications are heart failure, embolism and dysrhythmias. Herein we report a familial case of LVNC associated with a mutation in the MYH7 gene and review the literature regarding controversies in LVNC. A 50-year-old woman was referred to the cardiology clinic for palpitations. She underwent echocardiography and cardiac magnetic resonance imaging that revealed mild left ventricular systolic dysfunction and LVNC criteria. She had several episodes of non-sustained ventricular tachycardia and received an implantable cardioverter-defibrillator (ICD). Genetic testing revealed the c.1003G>C (p.Ala335Pro) mutation in the MYH7 gene. Familial screening showed clear genotype-phenotype cosegregation, which provided strong evidence for the pathogenic role of this mutation. To the best of our knowledge, this is the first report of LVNC associated with the p.Ala335Pro mutation in the MYH7 gene. This mutation has been described in hypertrophic cardiomyopathy, suggesting that the same pathogenic sarcomere mutation may be associated with different cardiomyopathies. This case also highlights the current difficulties regarding decisions on ICD implantation for primary prevention of sudden cardiac death in LVNC.     

Metabolism of non-steroidal anti-inflammatory drugs (NSAIDs) by Streptomyces griseolus CYP105A1 and its variants

In the field of drug development, technology for producing human metabolites at a low cost is required. In this study, we explored the possibility of using prokaryotic water-soluble cytochrome P450 (CYP) to produce human metabolites. Streptomyces griseolus CYP105A1 metabolizes various non-steroidal anti-inflammatory drugs (NSAIDs), including diclofenac, mefenamic acid, flufenamic acid, tolfenamic acid, meclofenamic acid, and ibuprofen. CYP105A1 showed 4′-hydroxylation activity towards diclofenac, mefenamic acid, flufenamic acid, tolfenamic acid, and meclofenamic acid. It should be noted that this reaction specificity was similar to that of human CYP2C9. In the case of mefenamic acid, another metabolite, 3′-hydroxymethyl mefenamic acid, was detected as a major metabolite. Substitution of Arg at position 73 with Ala in CYP105A1 dramatically reduced the hydroxylation activity toward diclofenac, flufenamic acid, and ibuprofen, indicating that Arg73 is essential for the hydroxylation of these substrates. In contrast, substitution of Arg84 with Ala remarkably increased the hydroxylation activity towards diclofenac, mefenamic acid, and flufenamic acid. Recombinant Rhodococcus erythrocyte cells expressing the CYP105A1 variant R84A/M239A showed complete conversion of diclofenac into 4′-hydroxydiclofenac. These results suggest the usefulness of recombinant R. erythropolis cells expressing actinomycete CYP, such as CYP105A1, for the production of human drug metabolites.