Adenosine(5') oligophospho-(5') guanosines and guanosine(5') oligophospho-(5') guanosines in human platelets.

We isolated and identified nucleoside(5') oligophospho-(5') nucleosides containing adenosine and guanosine (ApnG; n = 3-6) as well as diguanosine polyphosphates (GpnG; n = 3-6) in human platelets. For identification, UV spectrometry, matrix-assisted laser desorption/ionization, postsource decay matrix-assisted laser desorption/ionization mass spectrometry, and enzymatic cleavage experiments were used. The adenosine(5') oligophospho-(5') guanosines act as vasoconstrictors and growth factors. The diguanosine polyphosphates are potent modulators of growth in vascular smooth muscle cells, but do not affect vascular tone.     

Advances in mass spectrometry-based metabolomics for investigation of metabolites

Metabolomics is the systematic study of all the metabolites present within a biological system, which consists of a mass of molecules, having a variety of physical and chemical properties and existing over an extensive dynamic range in biological samples. Diverse analytical techniques are needed to achieve higher coverage of metabolites. The application of mass spectrometry (MS) in metabolomics has increased exponentially since the discovery and development of electrospray ionization and matrix-assisted laser desorption ionization techniques. Significant advances have also occurred in separation-based MS techniques (gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, capillary electrophoresis-mass spectrometry, and ion mobility-mass spectrometry), as well as separation-free MS techniques (direct infusion-mass spectrometry, matrix-assisted laser desorption ionization-mass spectrometry, mass spectrometry imaging, and direct analysis in real time mass spectrometry) in the past decades. This review presents a brief overview of the recent advanced MS techniques and their latest applications in metabolomics. The software/websites for MS result analyses are also reviewed.

Metabolomics is the systematic study of all the metabolites present within a biological system, supply functional information and has received extensive attention in the field of life sciences.     

MALDI: more than peptide mass fingerprints

Over the past decade, matrix-assisted laser desorption/ionization (MALDI) has developed from a phenomenon that was interesting only to physicists and mass spectrometrists, and has evolved into a widespread applied ionization technique in chemistry, biology and biomedicine. The introduction of MALDI offers all the advantages of mass spectrometry (MS) for the analysis of large biomolecules. Proteins, carbohydrates and oligonucleotides have been analyzed with MS-inherent accuracy, sensitivity, resolution and speed. In addition to electrospray ionization-MS, MALDI-MS has a great impact on the challenges of the post-genome area. The recent status of MALDI application in proteomics, biomolecular interaction analysis-MS and carbohydrate analysis, in addition to single nucleotide polymorphism genotyping is reviewed.     

Bioinformatics strategies for proteomic profiling

Clinical proteomics is an emerging field that involves the analysis of protein expression profiles of clinical samples for de novo discovery of disease-associated biomarkers and for gaining insight into the biology of disease processes. Mass spectrometry represents an important set of technologies for protein expression measurement. Among them, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI TOF-MS), because of its high throughput and on-chip sample processing capability, has become a popular tool for clinical proteomics. Bioinformatics plays a critical role in the analysis of SELDI data, and therefore, it is important to understand the issues associated with the analysis of clinical proteomic data. In this review, we discuss such issues and the bioinformatics strategies used for proteomic profiling.     

非霍奇金淋巴瘤血清蛋白质质谱分析

目的：应用表面增强激光解析电离飞行时间质谱技术检测血清蛋白指纹图,通过差异蛋白组学筛选非霍奇金淋巴瘤（nonhodgkin’s lymphoma,NHL）特有的蛋白标记物,找出最佳的标志蛋白组合模式建立非霍奇金淋巴瘤诊断模型。方法：用Ciphergen公司生产的PBSII／C型蛋白质指纹图谱仪和AuChpi金芯片采集50例NHL患者（NHI。组）、50例淋巴结炎患者（淋巴结炎组）、50例健康志愿者（对照组）血清蛋白质指纹图谱,采用BiomakerWizard3．1版分析软件筛选差异蛋白,建立NHL诊断模型。结果：NHL患者、淋巴结炎患者、健康志愿者血清蛋白质指纹图谱之间有4个标志蛋白在NHL患者血清中高表达,3个标志蛋白在NHL血清中低表达。分析系统筛选出质荷比（M／Z）4966、9278、6633、4222、9216、9237和7714标志蛋白建立NHL诊断模型,该模型对NHL的诊断灵敏度和特异性分别为92％和98％。结论：NHL与淋巴结炎组、对照组比较血清蛋白质表达具有显著差异,筛选其中差异蛋白质可用于建立NHL预测模型。     

High-throughput homogeneous mass cleave assay technology for the diagnosis of autosomal recessive Parkinson's disease

To date, 11 gene loci that contribute to familial Parkinson's disease (PD) are known. Of these, mutations in six genes have been identified, allowing genetic testing and more accurate phenotypic characterization of genetically defined disease subtypes. In particular, mutations in Parkin, DJ-1, and Pink1 genes are associated with autosomal recessive PD and may also play a major role in early onset PD (EOPD). However, genetic testing for sequence alterations in these genes remains laborious. Therefore, our aim was to develop a flexible, rapid, high-throughput screening procedure using matrix-assisted laser desorption ionization/time of flight technology and homogeneous mass cleave assays. Using this novel approach, we screened all 27 coding exons of the Parkin, DJ-1, and Pink1 genes in 31 patients with EOPD, a total of 367,195 nucleotides. Four positive controls with known autosomal recessive PD mutations that had previously been screened by denaturing high performance liquid chromatography in combination with sequencing were also tested. All known alterations were detected by matrix-assisted laser desorption ionization/time of flight mass spectrometer, as well as additional polymorphisms in formerly unscreened regions. Overall, two previously described mutations in three patients with EOPD, 27 known polymorphisms with 386 occurrences, and eight unknown variants with 21 occurrences were detected. In total, we identified 410 sequence alterations in 31 patients with EOPD. In conclusion, this is the first study using matrix-assisted laser desorption ionization/time of flight mass spectrometry and homogeneous mass cleave assay for high-throughput mutation screening.     

Proteomic applications in pathology and laboratory medicine: Present state and future prospects

Clinical mass spectrometry applications have traditionally focused on small molecules, particularly in the areas of therapeutic drug monitoring, toxicology, and measurement of endogenous and exogenous steroids. More recently, the use of matrix assisted laser desorption/ionization time of flight mass spectrometry for the identification of microbial pathogens has been widely implemented. Following this evolution, there has been an expanding role for the measurement of peptides and proteins in pathology and laboratory medicine. This review explores the current state of protein measurement by clinical mass spectrometry and the analytical strategies employed, as well as emerging applications in clinical chemistry, clinical microbiology and anatomical pathology.     

Preanalytic influence of sample handling on SELDI-TOF serum protein profiles

BACKGROUND: High-throughput proteomic methods for disease biomarker discovery in human serum are promising, but concerns exist regarding reproducibility of results and variability introduced by sample handling. This study investigated the influence of different preanalytic handling methods on surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) protein profiles of prefractionated serum. We investigated whether older collections with longer sample transit times yield useful protein profiles, and sought to establish the most feasible collection methods for future clinical proteomic studies. METHODS: To examine the effect of tube type, clotting time, transport/incubation time, temperature, and storage method on protein profiles, we used 6 different handling methods to collect sera from 25 healthy volunteers. We used a high-throughput, prefractionation strategy to generate anion-exchange fractions and examined their protein profiles on CM10, IMAC30-Cu, and H50 arrays by using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. RESULTS: Prolonged transport and incubation at room temperature generated low mass peaks, resulting in distinctions among the protocols. The most and least stringent methods gave the lowest overall peak variances, indicating that proteolysis in the latter may have been nearly complete. For samples transported on ice there was little effect of clotting time, storage method, or transit time. Certain proteins (TTR, ApoCI, and transferrin) were unaffected by handling, but others (ITIH4 and hemoglobin beta) displayed significant variability. CONCLUSIONS: Changes in preanalytical handling variables affect profiles of serum proteins, including proposed disease biomarkers. Proteomic analysis of samples from serum banks collected using less stringent protocols is applicable if all samples are handled identically.     

Investigation of molecular interaction within biological macromolecular complexes by mass spectrometry

The advent of electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) has accelerated structural studies of biological macromolecular complexes. At present, mass spectrometry can provide accurate mass values not only of individual biological macromolecules but also of their assemblies. Furthermore, it can also give information on the interface sites of the biological macromolecular complexes. The present article focuses on the role of mass spectrometry in the investigation of biological molecular interactions, such as protein-protein, protein-DNA, and protein-ligand interactions, which play essential roles in various biological events.     

Phenotype determination of hemoglobinopathies by mass spectrometry

Objectives

Nowadays, nearly 1000 hemoglobin (Hb) variants are known. The standard biochemical techniques used in Hb analysis are mainly: isoelectric focusing, cation-exchange liquid chromatography (LC) and reversed-phase LC. In addition to this approach, a protein analysis is achieved by mass spectrometry (MS) and additional DNA studies are performed. The aim of this review is to emphasize the significance of MS methods applied to Hb variants analysis.

Results and perspectives

To perform Hb studies, different MS techniques are currently used such as electrospray ionization (ESI), matrix-assisted laser desorption ionization (MALDI) and tandem mass spectrometry (MS/MS). As shown here, MS is an efficient tool for identification of all types of variants (substitution of a single amino acid residue, several substitutions in the same globin chain, insertions/deletions, fusion Hbs). The use of MS in neonatal screening of Hb variants is also presented.

Conclusions

MS is a powerful technique for Hb analysis. It appears as being an important additional method in the set of biochemical techniques.     

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry combined with chemometrics to identify the origin of Chinese medicinal materials

Geographical origin and authenticity are two core factors to promote the development of traditional Chinese medicine (TCM) herbs perception in terms of quality and price. Therefore, they are important to both sellers and consumers. Herein, we propose an efficient, accurate method for discrimination of genuine and non-authentic producing areas of TCM by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Take Atractylodes macrocephala Koidz (AMK) of compositae as an example, the MALDI-TOF MS spectra data of 120 AMK samples aided by principal component analysis-linear discriminant analysis (PCA-LDA), partial least squares discriminant analysis (PLS-DA) and random forest (RF) successfully differentiated Zhejiang province, Anhui province and Hunan province AMK according to their geographical location of origin. The correct classification rates of test set were above 93.3%. Furthermore, 5 recollected AMK samples were used to verify the performance of the classification models. The outcome of this study can be a good resource in building a database for AMK. The combined utility of MALDI-TOF MS and chemometrics is expected to be expanded and applied to the origin traceability of other TCMs.

The flow chart for geographical origin traceability of AMK based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry combined with chemometrics.     

Matrix-assisted laser desorption/ionization mass spectrometric analysis of DNA on microarrays

BACKGROUND: Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is a powerful tool in biomolecule analysis with a wide range of application possibilities, including genotyping of single-base variations (also known as single-nucleotide polymorphisms, or SNPs) for candidate gene studies and diagnostic typing of DNA markers. We tested a method that does not require stringent purification of the nucleic acids and/or the use of modification chemistry before mass spectrometry analysis. METHODS: We used an alternative direct analysis approach that allows MALDI analysis of crude DNA samples printed on microscope slides densely coated with primary amino groups that efficiently bind negatively charged DNA. After simple washing of the slides, we applied MALDI matrix and used a conventional MALDI mass spectrometer to detect DNA products. RESULTS: We analyzed crude oligonucleotide samples and performed automated genotyping of single-base variations in 72 DNA samples. CONCLUSION: This procedure offers an operational short-cut compared with standard MALDI procedures for preparation of oligonucleotides, including purification, and thus is an efficient tool for genotyping applications, particularly those requiring accurate, flexible, and rapid data generation and medium throughput.     

应用SELDI-TOF-MS技术诊断2型糖尿病肾病

目的比较2型糖尿病(T2DM)肾病和对照人群血清蛋白质指纹图谱的差异,建立T2DM肾病诊断模型,探讨此技术对该病诊断的价值。方法采用表面增强激光解析电离飞行时间质谱(SELDI-TOF-MS)技术检测51例T2DM肾病患者和66例对照人群血清,获得蛋白质指纹图谱。结合人工神经网络软件建立诊断模型并进行验证。结果在相对分子量2 000~30 000范围内共检测到175个蛋白峰,其中有17个蛋白峰明显表达差异(P<0.01)。筛选其中质荷比(m/z)分别为5 420、5 782、6 472、6 666、10 277和11 770的6个蛋白峰作为标志蛋白建立人工神经网络诊断模型。利用该模型对T2DM肾病进行盲法预测,结果表明其对该病的诊断敏感性和特异性分别为81.0%和96.2%。结论利用SELDI-TOF-MS和生物信息学技术建立了敏感性和特异性均较高的T2DM肾病诊断模型,为该病诊断提供了新途径。     

A peptide with a ProGln C terminus in the human saliva peptidome exerts bactericidal activity against Propionibacterium acnes

Nine proline-rich peptides ending with a proline-glutamine C terminus in a salivary peptidome were sequenced by matrix-assisted laser desorption ionization time of flight time of flight tandem mass spectrometry. A GPPPQGGRPQ peptide binds gram-positive Propionibacterium acnes and considerably inhibits bacterial growth. The peptide exhibiting innate immunity may be applied for treatment of various P. acnes-associated human diseases.     

利用SELDI-TOF-MS蛋白质指纹图谱技术建立肺腺癌诊断模型

目的:寻找肺腺癌患者血浆(清)蛋白特异性生物标志物,用最佳的标志蛋白组合建立肺腺癌诊断模型,并探讨其用于肺腺癌筛查的可行性.方法:应用表面增强激光解吸电离飞行时间质谱(SELDI-TOF-MS)技术及CM10芯片,检测45例肺腺癌患者和40例正常人血清蛋白质指纹图谱,用Biomark Wizrd和Biomark Patterns Software软件对结果进行分析,建立肺腺癌诊断模型:双盲法分析另外19例肺腺癌和20例正常人血清的SELDI质谱数据,验证该模型诊断肺腺癌的准确度.结果:肺腺癌患者和正常人血清蛋白质指纹图谱间有31个差异蛋白(P<0.05),其中以分子量为11.66 kD的蛋白在两组血清中的差异最为显著(P<10-7),该蛋白对诊断肺腺癌有很强的敏感性和特异性;软件自动筛选出分子量为11.66 kD的标志蛋白为主根结点,联合3882.9、4673.2、3158.2和2047.2等4个标志蛋白建立了最佳的肺腺癌诊断模型,对肺腺癌诊断(盲法)的敏感性为84.2%(16/19),特异性为90.0%(18/20).结论:SELDI-TOF-MS技术建立的肺腺癌血清检测法,快速、简单、特异和敏感,为肺腺癌诊断和筛查提供了一个可行的途径和方法.     

The MALDI-TOF mass spectrometric view of the plasma proteome and peptidome

BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and the related technique, surface-enhanced laser desorption/ionization (SELDI)-TOF MS, are being applied widely to analyze serum or plasma specimens for potential disease markers. METHODS: Reports on the basic principles and applications of MALDI-TOF MS were reviewed and related to information on abundance and masses of major plasma proteins. Outcomes: MALDI-TOF MS is a particle-counting method that responds to molar abundance, and ranking of plasma proteins by molar abundance increases the rank of small proteins relative to traditional ranking by mass abundance. Detectors for MALDI-TOF MS augment the bias for detecting smaller components by yielding stronger signals for an equivalent number of small vs large ions. Consequently, MALDI-TOF MS is a powerful tool for surveying small proteins and peptides comprising the peptidome or fragmentome, opening this new realm for analysis. It is complementary to techniques such as electrophoresis and HPLC, which have a bias for detecting larger molecules. Virtually all of the potential markers identified by MALDI-TOF MS to date represent forms of the most abundant plasma proteins. CONCLUSIONS: Analyses of serum or plasma by MALDI-TOF MS provide new information mainly about small proteins and peptides with high molar abundance. The spectrum of observed proteins and peptides suggests value for applications such as assessment of cardiovascular risk, nutritional status, liver injury, kidney failure, and systemic immune responses rather than early detection of cancer. Extending analysis by MALDI-TOF MS to lower abundance components, such as markers for early-stage cancers, probably will require more extensive specimen fractionation before analysis.     

Tree analysis of mass spectral urine profiles discriminates transitional cell carcinoma of the bladder from noncancer patient

BACKGROUND: Recent advances in proteomic profiling technologies, such as surface-enhanced laser desorption/ionization mass spectrometry (SELDI), have allowed preliminary profiling and identification of tumor markers in biological fluids in several cancer types and establishment of clinically useful diagnostic computational models. We developed a bioinformatics tool and used it to identify proteomic patterns in urine that distinguish transitional cell carcinoma (TCC) from noncancer. METHODS: Proteomic spectra were generated by mass spectroscopy (surface-enhanced laser desorption and ionization). A preliminary "training" set of spectra derived from analysis of urine from 46 TCC patients, 32 patients with benign urogenital diseases (BUD), and 40 age-matched unaffected healthy men were used to train and develop a decision tree classification algorithm that identified a fine-protein mass pattern that discriminated cancer from noncancer effectively. A blinded test set, including 38 new cases, was used to determine the sensitivity and specificity of the classification system. RESULTS: The algorithm identified a cluster pattern that, in the training set, segregated cancer from noncancer with sensitivity of 84.8% and specificity of 91.7%. The discriminatory pattern correctly identified. A sensitivity of 93.3% and a specificity of 87.0% for the blinded test were obtained when comparing the TCC vs. noncancer. CONCLUSIONS: These findings justify a prospective population-based assessment of proteomic pattern technology as a screening tool for bladder cancer in high-risk and general populations.     

Proteomic patterns as a diagnostic tool for early-stage cancer: a review of its progress to a clinically relevant tool.

The pace of development in novel technologies that promise improvements in the early diagnosis of disease is truly impressive. One such technology at the forefront of this revolution is mass spectrometry. New capabilities in mass spectrometry have provided the means for the development of proteomics, and the race is on to find innovative ways to apply this powerful technology to solving the problems faced in clinical medicine. One area that has garnered much attention over the past few years is the use of mass spectral patterns for cancer diagnostics. The use of these so-called 'proteomic patterns' for disease diagnosis relies fundamentally on the pattern of signals observed within a mass spectrum rather than the more conventional identification and quantitation of a biomarker such as in the case of cancer antigen-125- or prostate-specific antigen. The inherent throughput of proteomic pattern technology enables the analysis of hundreds of clinical samples per day. Currently, there are two primary means by which proteomic patterns can be acquired, surface-enhanced laser desorption/ionization (SELDI) and an electrospray ionization (ESI) method that has been popularized under the name, OvaCheck. In this review, an historical perspective on the development of proteomic patterns for the diagnosis of early-stage cancers is described. In addition, a critical assessment of the overall technology is presented with an emphasis on the steps required to enable proteomic pattern analysis to become a viable clinical tool for diagnosing early-stage cancers.     

Yokenella regensburgei necrotizing fasciitis in an immunocompromised host

We report a case of necrotizing skin infection caused by Yokenella regensburgei in an immunosuppressed patient with orthotopic liver transplantation. Initial bacterial culture identification was suggestive of Hafnia alvei. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) confirmed identification of Y. regensburgei. Necrotizing fasciitis is potentially fatal and requires aggressive management, including early diagnosis, appropriate antibiotic selection, and operative debridement.     

Identification of rat targets of anti-soluble liver antigen autoantibodies by serologic proteome analysis

BACKGROUND: Anti-soluble liver antigen (SLA) autoantibodies are specific for autoimmune hepatitis type 1 and are the only immunologic marker found in 15-20% of hepatitis cases previously considered cryptogenic. Anti-SLA antibodies react with the 100 000g supernatant from rat liver homogenate, but the molecular targets remain controversial. METHODS: We characterized anti-SLA targets by one- and two-dimensional immunoblotting analysis. The recognized proteins were identified by peptide mass fingerprint analysis after matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. RESULTS: Three proteins of 35 kDa and pI 6.0, 50 kDa and pI between 6.0 and 6.5, and 58 kDa and pI between 6.5 and 7.0 were stained more intensely by anti-SLA positive-sera than by control sera. After in-gel tryptic digestion, MALDI-TOF analysis of the generated peptides enabled the clear identification of N-hydroxyarylamine sulfotransferase, isoforms of alpha-enolase, and isoforms of catalase. CONCLUSIONS: Possible antigens for anti-SLA antibodies include a sulfotransferase, alpha-enolase(s), and catalase(s). Two-dimensional electrophoresis combined with mass spectrometry offers a versatile tool to identify molecular targets of autoantibodies and thus to improve diagnostic tools and the understanding of the immune process.