拉曼光谱检测微生物的研究方法和进展北大核心

快速准确地识别和鉴定微生物对于环境科、食品质量以及医学诊断等领域研究至关重要。拉曼光谱(Raman spectroscopy)已经被证明是一种能够实现微生物快速诊断的新技术,在提供微生物指纹图谱信息的同时,能够快速、非标记、无创、敏感地在固体和液体环境中实现微生物单细胞水平的检测。本文简单介绍了拉曼光谱的基本概念和原理,重点综述了拉曼光谱微生物检测应用中的样品处理方法及光谱数据处理方法。除此之外,本文概括了拉曼光谱在细菌、病毒和真菌中的应用,其中单独概括了拉曼在细菌快速鉴定和抗生素药敏检测中的应用。最后,本文阐述了拉曼光谱在微生物检测中的挑战和展望。     

非标记表面增强拉曼光谱在病原菌检测中的应用

目前世界上已有的病原菌检测方法尚不能实现对病原菌的快速准确鉴定,因而研究建立能够快速准确鉴定病原菌的方法是微生物检测方面的重要方向。表面增强拉曼光谱具有检测灵敏度高、速度快、成本低、便携性好等优点,成为检测病原菌的一个极具潜力的新方法。本文简要介绍非标记表面增强拉曼光谱在病原菌检测方面的应用。     

过氧化氢对Ⅱ型胶原损伤的拉曼光谱研究

拉曼光谱技术是研究生物分子结构的重要工具,其具有快速、无损、实时检测等优点。在本文中,我们运用拉曼光谱技术研究过氧化氢对关节软骨Ⅱ型胶原的损伤,检测关节软骨Ⅱ型胶原氧化损伤前后的拉曼光谱,以期探讨关节软骨Ⅱ型胶原氧化损伤分子改变机制。我们发现,过氧化氢可导致II型胶原分子内氢键体系发生改变,脯氨酸及羟基氨酸的羟基化程度降低,从而引起主链及侧链构象改变,导致三螺旋结构遭到破坏。总之,本文借助于拉曼光谱技术发现了过氧化氢对Ⅱ型胶原的损伤机制。     

拉曼光谱在胃癌诊断中的应用与研究进展

拉曼光谱是一种分子振动光谱技术,具有分子水平的肿瘤检测和诊断能力.胃癌是常见恶性肿瘤,经常到晚期才得到诊断,死亡率较高,而早期胃癌预后较好,因此胃癌早期检测和诊断显得尤为重要.文章介绍了拉曼光谱用于胃癌早期检测和诊断的应用,并综述其研究进展,结果认为拉曼光谱探针与内镜整合,将实现胃癌活体检测和诊断,极具临床应用价值.     

功能红细胞研究的拉曼光谱技术与进展

红细胞在人体新陈代谢和物质运输方面起着非常重要的作用。作为一种无损、快速而灵敏的光谱学检测方法,拉曼光谱技术在生物医学领域的应用日渐广泛。本文综述了近年来拉曼光谱技术在红细胞及血红蛋白研究中的应用进展,详尽评述当前研究功能红细胞中较有优势的拉曼技术—显微拉曼光谱技术和光镊拉曼光谱技术,并对其技术的改进做出总结,以期为利用激光拉曼光谱研究红细胞提供较系统的参考。     

非标记表面增强拉曼光谱在DNA检测中的应用

表面增强拉曼光谱(SERS)是一种超灵敏的生化分析技术,已经被广泛运用于细胞、核酸、蛋白质等生物分子的检测,在生物医学领域表现出了巨大的应用潜力。近年来,将表面增强拉曼光谱技术应用于遗传物质DNA的精准检测,引起了人们广泛的关注。本文简要叙述了表面增强拉曼光谱技术的基本原理及其在DNA检测中的优势,主要介绍了非标记的DNA-SERS检测应用进展,其中包括本项目组的相关工作。研究表明,非标记DNA-SERS技术有望成为一种快速、准确的临床诊断方式。     

拉曼光谱在皮肤领域的研究进展

拉曼光谱是一种新型的光学检测技术,常用于材料鉴定。近年来,随着无创检测需求的增加,拉曼光谱逐渐应用于疾病诊断、物质鉴别等生物领域。综述了拉曼光谱在皮肤领域的研究进展,及其对皮肤组织成分鉴别和皮肤疾病诊断的价值,以期推动拉曼光谱广泛应用于皮肤病学的机理研究和临床诊断。     

拉曼光谱技术在肿瘤检测中的应用

癌症是威胁人类健康和生命的严重疾病之一,早期诊断与及时治疗是提高癌症患者生存率的最有效途径。激光拉曼光谱技术作为一种非侵入性的检测技术,可以无损伤地提供丰富的分子结构特征和物质成分信息,从分子水平上反映癌变组织与正常组织之间的结构差异,从而可用于癌症的早期诊断。综述了激光拉曼光谱技术在皮肤癌、鼻咽癌、肺癌、胃癌、结肠癌、乳腺癌及前列腺癌诊断中的研究进展,并对拉曼光谱技术在癌症诊断中的发展方向和应用前景作了进一步的展望,为癌症的早期检测和诊断技术的应用研究提供参考依据。     

基于纳米信号标签的表面增强拉曼散射在病原菌检测中的应用

表面增强拉曼散射(surface-enhanced Ranan scattering,SERS)技术由于其灵敏度高、检测速度快、高特异性和无损等优点,在病原菌检测领域受到了广泛的关注.主要总结了近年来基于纳米信号标签的SERS方法在检测病原菌领域中的研究进展,并介绍了多功能SERS检测平台的构建及在病原菌检测中的应用....     

拉曼光谱技术在微生物学中的应用

拉曼光谱具有快速、灵敏、无损、实时监测等显著特点,在微生物学领域得到广泛应用。分别介绍共焦显微拉曼光谱、共振拉曼光谱、表面增强拉曼光谱、拉曼成像、相干反斯托克斯拉曼光谱、激光镊子拉曼光谱和Raman-FISH的原理和特点,并重点总结和分析不同拉曼光谱技术在微生物的结构、化学组成,以及代谢过程等相关研究中的应用优势。合理利用这些技术在基础微生物、发酵微生物和微生物诊断等方面具有潜在的应用价值。     

乳杆菌对生物膜的作用及其机制研究进展

慢性炎症和感染性疾病与致病菌生物膜(biofilm,BF)的形成密切相关,目前治疗BF相关疾病还局限于应用抗生素,但抗生素滥用会导致多重耐药,治疗不彻底会引起慢性感染,预防和治疗BF相关疾病的新方法亟待提出。随着益生菌生物制剂应用价值的不断体现与验证,益生菌生物制剂不断发展为消除某些致病菌BF感染的新方案。其中发展的最好的莫过于乳杆菌活菌制剂,大量的科研文献及临床实践已证明其具有强大的益生潜力,特别是在抑制致病菌生物膜方面,这为临床治疗BF相关感染开拓了新视野。本文主要综述当前国内外乳杆菌对生物膜作用及其机制的研究进展,旨在通过综述相关研究进展为临床治疗生物膜相关感染提供全新思路。     

Applications of sequencing technology in clinical microbial infection

Infectious diseases are a type of disease caused by pathogenic microorganisms. Although the discovery of antibiotics changed the treatment of infectious diseases and reduced the mortality of bacterial infections, resistant bacterial strains have emerged. Anti‐infective therapy based on aetiological evidence is the gold standard for clinical treatment, but the time lag and low positive culture rate of traditional methods of pathogen diagnosis leads to relative difficulty in obtaining the evidence of pathogens. Compared with traditional methods of pathogenic diagnosis, next‐generation and third‐generation sequencing technologies have many advantages in the detection of pathogenic microorganisms. In this review, we mainly introduce recent progress in research on pathogenic diagnostic technology and the applications of sequencing technology in the diagnosis of pathogenic microorganisms. This review provides new insights into the application of sequencing technology in the clinical diagnosis of microorganisms.     

Application of oligonucleotide array technology for the rapid detection of pathogenic bacteria of foodborne infections

A rapid and accurate method for detection for common pathogenic bacteria in foodborne infections was established by using oligonucleotide array technology. Nylon membrane was used as the array support. A mutation region of the 23S rRNA gene was selected as the discrimination target from 14 species (genera) of bacteria causing foodborne infections and two unrelated bacterial species. A pair of universal primers was designed for PCR amplification of the 23S rRNA gene. Twenty-one species (genera)-specific oligonucleotide detection probes were synthesized and spotted onto the nylon membranes. The 23S rRNA gene amplification products of 14 species of pathogenic bacteria were hybridized to the oligonucleotide array. Hybridization results were analyzed with digoxigenin-linked enzyme reaction. Results indicated that nine species of pathogenic bacteria (Escherichia coli, Campylobacter jejuni, Shigella dysenteriae, Vibrio cholerae, Vibrio parahaemolyticus, Proteus vulgaris, Bacillus cereus, Listeria monocytogenes and Clostridium botulinum) showed high sensitivity and specificity for the oligonucleotide array. Two other species (Salmonella enterica and Yersinia enterocolitica) gave weak cross-reaction with E. coli, but the reaction did not affect their detection. After redesigning the probes, positive hybridization results were obtained with Staphylococcus aureus, but not with Clostridium perfringens and Streptococcus pyogenes. The oligonucleotide array can also be applied to samples collected in clinical settings of foodborne infections. The superiority of oligonucleotide array over other tests lies on its rapidity, accuracy and efficiency in the diagnosis, treatment and control of foodborne infections.     

Rapid diagnosis of infection etiology in febrile pediatric oncology patients using infrared spectroscopy of leukocytes

Rapid diagnosis of the etiology of infection is highly important for an effective treatment of the infected patients. Bacterial and viral infections are serious diseases that can cause death in many cases. The human immune system deals with many viral and bacterial infections that cause no symptoms and pass quietly without treatment. However, oncology patients undergoing chemotherapy have a very weak immune system caused by leukopenia, and even minor pathogen infection threatens their lives. For this reason, physicians tend to prescribe immediately several types of antibiotics for febrile pediatric oncology patients (FPOPs). Uncontrolled use of antibiotics is one of the major contributors to the development of resistant bacteria. Therefore, for oncology patients, a rapid and objective diagnosis of the etiology of the infection is extremely critical. Current identification methods are time‐consuming (>24 h). In this study, the potential of midinfrared spectroscopy in tandem with machine learning algorithms is evaluated for rapid and objective diagnosis of the etiology of infections in FPOPs using simple peripheral blood samples. Our results show that infrared spectroscopy enables the diagnosis of the etiology of infection as bacterial or viral within 70 minutes after the collection of the blood sample with 93% sensitivity and 88% specificity.     

Profiling antibiotic resistance in Escherichia coli strains displaying differential antibiotic susceptibilities using Raman spectroscopy

The rapid identification of antibiotic resistant bacteria is important for public health. In the environment, bacteria are exposed to sub-inhibitory antibiotic concentrations which has implications in the generation of multi-drug resistant strains. To better understand these issues, Raman spectroscopy was employed coupled with partial least squares-discriminant analysis to profile Escherichia coli strains treated with sub-inhibitory concentrations of antibiotics. Clear differences were observed between cells treated with bacteriostatic (tetracycline and rifampicin) and bactericidal (ampicillin, ciprofloxacin, and ceftriaxone) antibiotics for 6 hr: First, atomic force microscopy revealed that bactericidal antibiotics cause extensive cell elongation whereas short filaments are observed with bacteriostatic antibiotics. Second, Raman spectral analysis revealed that bactericidal antibiotics lower nucleic acid to protein (I₈₁₂/I₈₃₀) and nucleic acid to lipid ratios (I₁₄₈₃/I₁₄₅₂) whereas the opposite is seen with bacteriostatic antibiotics. Third, the protein to lipid ratio (I₂₉₃₆/I₂₈₈₅ and I₂₉₃₆/I₂₈₅₀) is a Raman stress signature common to both the classes. These signatures were validated using two mutants, Δlon and ΔacrB, that exhibit relatively high and low resistance towards antibiotics, respectively. In addition, these spectral markers correlated with the emergence of phenotypic antibiotic resistance. Overall, this study demonstrates the efficacy of Raman spectroscopy to identify resistance in bacteria to sub-lethal concentrations of antibiotics.     

浅述乳酸菌在畜禽生产中的应用

在病原菌、病毒、应激等因素的影响下,畜禽肠道功能容易紊乱失调。抗生素可以预防或治疗由病原菌引起的感染,但抗生素的滥用会给畜牧产品、生态环境带来一系列危害,对人类的健康造成巨大威胁,因此无抗养殖的趋势已成必然。益生菌在畜禽养殖中具有很重要的作用,乳酸菌作为益生菌的重要组成部分,它具有促进机体生长、改善胃肠道功能、提高机体免疫力、维持动物肠道菌群平衡等作用,故乳酸菌可以作为抗生素替代品引入畜禽养殖。本文主要概述乳酸菌在畜禽养殖中发挥益生功效的作用机制和应用范围,着重讲述乳酸菌相较于其他主要畜禽养殖益生菌的优势与劣势,阐述乳酸菌在种养结合的运用,对乳酸菌的未来发展和应用前景提出展望。     

Isolation and identification of lipopeptide antibiotics from <Emphasis Type="Italic">Paenibacillus elgii</Emphasis> B69 with inhibitory activity against methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

Two lipopeptide antibiotics, pelgipeptins C and D, were isolated from Paenibacillus elgii B69 strain. The molecular masses of the two compounds were both determined to be 1,086 Da. Mass-spectrometry, amino acid analysis and NMR spectroscopy indicated that pelgipeptin C was the same compound as BMY-28160, while pelgipeptin D was identified as a new antibiotic of the polypeptin family. These two peptides were active against all the tested microorganisms, including antibiotic-resistant pathogenic bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA). Time-kill assays demonstrated that pelgipeptin D exhibited rapid and effective bactericidal action against MRSA at 4×MIC. Based on acute toxicity test, the intraperitoneal LD50 value of pelgipeptin D was slightly higher than that of the structurally related antimicrobial agent polymyxin B. Pelgipeptins are highly potent antibacterial and antifungal agents, particularly against MRSA, and warrant further investigation as possible therapeutic agents for bacteria infections resistant to currently available antibiotics.