Surface-enhanced Laser Desorption/ionization Time-of-flight Mass Spectrometry Research Articles

The influence of microbial bacterial proteins on metabolites in the chilled tan sheep meat

This study aims to investigate experimentally the influence of microbial bacterial proteins on microbial metabolites in the chilled storage of Tan Sheep meat based on the surface enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS) and gas chromatography-time of flight-mass spectrometry (GC-TOF MS). The correlation analysis of differentially abundant proteins and differential metabolites detected simultaneously in different storage periods has been carried out by heatmap analysis. The results show that 30 differential expressed metabolites were statistically significant. These metabolites were identified as potential spoilage biomarkers. Among of them, 25 differential expressed metabolites can be matched to KEGG metabolic pathways. cyano-amino-acid pathway, pentose phosphate pathway, histidine pathway, purine metabolic pathways, lanine, aspartic acid and glutamate pathway were highly active. Therefore, the differentially abundant proteins contents of microbiology in metabolism can lead to differential effects on metabolic pathways.

Diagnostic value of combining tumor and inflammatory biomarkers in detecting common cancers in Korea

BackgroundThe ultimate goal of cancer screening is to diagnose invasive cancers early, while they are still curable. We aimed to validate the diagnostic value of blood-derived protein biomarkers that we developed for six common cancer in Korea. MethodsWe have discovered 12 protein biomarkers that are useful in differentiating cancer patients from healthy controls using two-dimensional gel electrophoresis (2-DE), surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS), and literature review. Cancer patients (stomach, colon, liver, lung, breast, and prostate) and control subjects were collected and tested data sets were used to generate predictive models that identify risk scores for each cancer. The validation study was done in serum samples of an independent patient cohort Receiver operating characteristic (ROC) analyses were conducted to evaluate the diagnostic performance of the biomarkercombinations. ResultsThe AUCs of the model in the test set were 0.971, 0.960, 0.969, 0.942, 0.834, and 0.985 for stomach, colon, liver, lung, breast, and prostate cancer, respectively. ConclusionsCombining multiple tumor and systemic inflammatory biomarkers proved to be a valid strategy in the diagnosis of six common cancers in Korea. Further validation of appropriate screening populations through large-scale clinical trials are warranted.

Screening of serum protein biomarkers in hemorrhagic cerebral infarction by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technology.

BackgroundSerum samples of patients with hemorrhagic cerebral infarction (HCI), cerebral infarction (CI), and healthy controls (HCs) were used to screen statistically different protein peaks as potential biomarkers and to establish a decision tree classification model.MethodsThe serum samples from clinically confirmed patients with HCI and CI from November 2018 to October 2019 were collected, along with those of HCs who visited our hospital during the same period. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) with CM10 ProteinChip was used to analyze the differences in serum protein expression profiles of 30 patients with HCI, 32 patients with CI, and 31 HCs in the training group, and a decision tree classification model was established. At the same time, the blind test group (18 patients with HCI, 21 patients with CI, and 17 HCs) was tested by a blind method.ResultsModel 1 was successfully established by software analysis with a mass-to-charge ratio of 3,495.2, 8,941.0, and 15,890.4 as a differential protein peak. The sensitivity, specificity, and accuracy of model 1 in distinguishing HCI from HCs were 86.8%, 87.1%, and 86.9%, respectively. After verification of model 1 by the blind test group, the results showed that the sensitivity, specificity, and accuracy were 88.9%, 94.1%, and 91.4%, respectively. The sensitivity, specificity, and accuracy of model 2 with a mass-to-charge ratio of 2,941.3 as a differential protein peak were 86.7%, 75.0%, and 80.6%, respectively. After verification of model 2 by the blind test group, the results showed that the sensitivity, specificity, and accuracy were 83.3%, 90.4%, and 87.2%, respectively.ConclusionsSurface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) and CM10 ProteinChip can be used to screen serum protein markers in patients with HCI. Mass-to-charge ratio of 3,495.2, 8,941.0, 15,890.4, and 2,941.3 may be potential protein biomarkers of HCI and used to distinguish HCI patients from HCs and CI.

High-throughput screening of bisphenols using magnetic covalent organic frameworks as a SELDI-TOF-MS probe.

Core-shell structured magnetic covalent organic framework (Fe3O4@COF) nanospheres were rapidly synthesized at room temperature using the monodisperse Fe3O4 nanoparticles (NPs) as magnetic core and benzene-1,3,5-tricarbaldehyde (BTA) and 3,3'-dihydroxybenzidine (DHBD) as two building blocks (denoted as Fe3O4@BTA-DHBD), respectively. They can serve as a mass spectrometry probe for rapid and high-throughput screening of bisphenols (BPs) from pharmaceuticals and personal care products (PPCPs) by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). The Fe3O4@BTA-DHBD nanospheres showed some superior features involving average pore size distribution (2.82nm), high magnetization values (42.5emug-1), high specific surface area (82.96m2g-1), and good chemical/thermal stability. It was used as both ideal adsorbent for enrichment of BPs and new substrate to assist ionization in SELDI-TOF-MS. The method exhibited good linearity in the range 0.05-4000ngmL-1 with correlation coefficients (r) higher than 0.9920. Lowlimits of detection (LODs) (500pgmL-1 for bisphenol A (BPA), 2pgmL-1 for bisphenol B (BPB), 28pgmL-1 for bisphenol C (BPC), 60pgmL-1 for bisphenol F (BPF), 33pgmL-1 for bisphenol AF (BPAF), 200pgmL-1 for bisphenol BP (BPBP), 10pgmL-1 for bisphenol S (BPS), 90pgmL-1 for tetrabromobisphenol A (BPA(Br)4), and 380pgmL-1 for tetrabromobisphenol S (BPS(Br)4)) and good recoveries (80.6-115%) of BPs in PPCPs were achieved. The relative standard deviations (RSDs) of spot-to-spot (n = 10) and sample-to-sample (n = 5) were in the ranges 5-11% and 5-12%, respectively. The dual-function platform was successfully applied to the quantitative determination of BPs in PPCPs. It not only expanded the scope of the application of COFs but also provided an alternative strategy for the determination of hazardous compounds in PPCPs. Graphical abstract Schematic representation of the synthesis of core-shell structured magnetic covalent organic framework nanospheres (Fe3O4@COFs) and its application in the analysis of bisphenols by using Fe3O4@BTA-DHBD nanospheres as a MS probe based on surface-enhanced laser desorption/ionization time-of-flight mass spectrometry.

An efficient biomarker panel for diagnosis of breast cancer using surface-enhanced laser desorption ionization time-of-flight mass spectrometry.

Breast cancer (BC) is the most frequently diagnosed cancer that affects women worldwide. Early detection of BC is important to improve survival rates and decrease mortality. The aim of the present study was to investigate serum biomarkers using surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS) to distinguish patients with BC from the healthy population and patients with benign breast diseases (BBDs). A total of 62 patients with invasive ductal carcinoma, as confirmed by histopathology, and 47 non-cancerous individuals (NCIs) [16 healthy controls (HCs) and 31 patients with BBD] were enrolled in the present study. Serum protein profiles were determined by SELDI-TOF-MS using an immobilized metal affinity capture array. Serum from patients with BC were compared with that from the HC group using univariate and multivariate statistical analyses. A total of 118 clusters were generated from the individual serum. Univariate analysis revealed that 5 peaks were significantly downregulated (m/z 1,452, 2,670, 3,972, 5,354 and 5,523; P<0.001) and 4 were upregulated (m/z 6,850, 7,926, 8,115 and 8,143; P<0.001) in patients with BC compared with the HC group. A comparison of patients with BC and patients with BBD revealed an additional 9 protein peaks. Among these, 3 peaks (m/z 3,972, 5,336 and 11,185) were significantly downregulated and 6 peaks (m/z 4,062, 4,071, 4,609, 6,850, 8,115 and 8,133) were significantly upregulated. A total of 3 peaks [mass-to-change ratio (m/z) 3,972, 6,850 and 8,115 (BC2)] were common in both sets. The results of the present study suggest that a 4 protein peak set [m/z 3,972, 6,850 and 8,115 (BC2) and 8,949 (BC3)] could be used to distinguish patients with BC from NCI.

Anaphylatoxin C3a: A potential biomarker for esophageal cancer diagnosis.

Esophageal carcinoma is a common malignancy worldwide, with a low 5-year survival rate. As the majority of cases are diagnosed at an advanced stage, there is an urgent need for an effective biomarker for early diagnosis of esophageal cancer patients. Surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS) was applied to detect the serum protein expression in esophageal cancer patients using ProteinChip software, and the results were analyzed and screened using Biomarker Patterns and SPSS16.0 software. The ELISA method was conducted to determine the concentration of anaphylatoxin C3a, which is one of the complement proteins, in the serum of esophageal cancer patients and non-esophageal cancer participants. A total of 144 effective differential expression protein peaks in the window of 1-10 kDa were obtained (P<0.05). M/Z 8,926.478 (P<10-6) protein peak was employed as the diagnostic biomarker for esophageal carcinoma. This established diagnostic biomarker has a sensitivity of 95% (19/20) and an accuracy of 100% (19/19) for positive prediction. The results suggested that anaphylatoxin C3a may be a promising biomarker in the diagnosis of esophageal carcinoma, and may play a key role in promoting esophageal carcinogenesis.

Differential proteome profile in ischemic heart disease: Prognostic value in chronic angina versus myocardial infarction. A proof of concept

The initial clinical manifestation of ischemic heart disease (IHD) i.e. unheralded myocardial infarction (MI) versus chronic angina pectoris (AP) is statistically associated with adverse or mild disease progression respectively in the long-term follow-up. Here, we subjected AP and MI patients to blood proteomic analysis by Surface-Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SELDI-TOF-MS) in order to investigate putative new prognostic biomarkers of IHD manifestation. We found several differentially expressed peaks but four of them (4176, 4475, 14,158m/z and 8922m/z for AP and MI, respectively) were most reliable. Two of them were identified; 14,158m/z peak was the double-charged form of Apolipoprotein A-I and its vasoprotective action accords with prominence in AP. The 4176m/z peak was related to FAM83C protein, while neither the 4475m/z peak nor the MI-linked 8922m/z peak could be identified. We conclude that SELDI-TOF-MS analysis may yield a panel of molecular signals able to retrospectively classify patients according to their clinical and molecular features, exploitable for predicting the natural course of IHD.

Identification of Surface-Enhanced Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry as Predictors of Prognosis in Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) is characterized by lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expressions. Prognosis of TNBC is poor due to recurrence and cancer death even with complete tumor resection, and it remains unclear which biomarkers are clinically useful for prediction of recurrence. The aim of this study was therefore to identify biomarkers for prognosis of TNBC by using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). 51 cases of TNBC were collected, including 17 patients with recurrence or death and 34 patients with non-recurrence. Factors that were significantly associated (P < 0.05) with TNBN prognosis after statistical analysis included tumor size, menopausal status and lymph node metastasis. Seven statistical significant peaks were found after protein mass spectrometry, with corrected P < 0.05. The features were selected to predict the patient's outcome using Support Vector Machine (SVM) classifier. When all the peaks were combined to classify the two groups, we obtained high classification accuracy, sensitivity and specificity, which were 90.2%, 82.35% and 94.12%, respectively. The results indicated that the identified protein peaks are potential biomarkers for predicting the prognosis of TNBC patients.

Serum proteomic signatures as biomarkers of primary biliary cirrhosis diagnosis and prognosis.

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease considered as an autoimmune disease. To identify new biomarkers of PBC, serum profiling analysis using Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) was employed. Twelve patients with either asymptomatic PBC (group 1, n=6) or PBC with a poor response to UDCA (group 2, n=6), were compared to healthy controls (group 3, n=6). Analysing the 18 sera by using four SELDI-TOF arrays under various conditions, we found four biomarkers of PBC at 5.9, 8.6, 8.9 and 9.0 kDa. The combination of the two arrays IMAC-40/Zn2+ and CM-10/pH 7 improved the positive diagnosis of this disease. We also found a biomarker of severity of PBC at 95.2 kDa on LSAX-30 array which characterized patients with a bad prognosis. In conclusion, our study identified several serum proteomics signatures as potential biomarkers of PBC for its diagnosis or prognosis.

Diagnostic value of amniotic fluid inflammatory biomarkers for subclinical chorioamnionitis

ObjectiveTo determine the value of measuring amniotic fluid inflammatory biomarkers for diagnosis of subclinical chorioamnionitis. MethodsA prospective study was conducted among pregnant women with cervical dilation, preterm premature rupture of membranes, threatened late abortion, or threatened premature labor who attended a tertiary care hospital in Guangzhou, China, between June 1, 2012, and January 31, 2014. Participants were divided into two groups according to the presence or absence of subclinical chorioamnionitis. Surface-enhanced laser desorption/ionization time-of-flight mass spectroscopy (SELDI-TOF-MS) was used to detect human neutrophil defensins (HNP-1 and HNP-2), calgranulins A (S100A8), and calgranulins C (S100A12) in amniocentesis samples. ResultsOverall, 22 patients had subclinical chorioamnionitis and 17 patients did not. Positive test results for HNP-2 were noted for more patients with subclinical chorioamnionitis than for those without for HNP-2 (19 [86%] vs 2 [12%]; P<0.001), HNP-1 (19 [86%] vs 5 [29%]; P=0.001), S100A12 (20 [91%] vs 9 [53%]; P=0.011), and S100A8 (12 [55%] vs 0; P<0.001). When three or four of these biomarkers were present, the accuracy for a diagnosis of subclinical chorioamnionitis was 89.7%. The sensitivity, specificity, positive predictive value, and negative predictive value were 81.8%, 100.0%, 100.0%, and 81.0%, respectively. ConclusionDetection of inflammatory biomarkers in the amniotic fluid by SELDI-TOF-MS exhibited high diagnostic accuracy for subclinical chorioamnionitis.

Identification of Apolipoprotein C-I Peptides as a Potential Biomarker and its Biological Roles in Breast Cancer.

BackgroundBreast cancer (BC) is one of the most common cancers and is among the main causes of death in females around the world. Although several serum biomarkers have been identified for breast cancer, due to lack of adequate sensitivity and specificity they do not adequately distinguish BC from confounding conditions. New approaches are urgently needed to improve BC detection and treatment.Material/MethodsEighty serum samples from 20 healthy individuals and 60 patients with BC (22 triple-negative breast cancer, TNBC; 38 non-triple-negative breast cancer, NTNBC) were included. Protein profiling of serum samples was analyzed using surface-enhanced laser desorption/ionization time-of-flight mass spectroscopy (SELDI-TOF-MS). Candidate biomarkers were purified by SDS-PAGE electrophoresis and identified by MALDI-TOF/TOF.ResultsThe candidate biomarker positioned at 6447.9 m/z was significantly decreased in BC patients. Moreover, the expression intensity of the candidate biomarker was weaker in the TNBC and pre-surgery group compared with the NTNBC and post-surgery group. We ultimately identified the biomarker as apolipoprotein C-I (ApoC-I). Furthermore, we found that ApoC-I peptides inhibited proliferation of human breast cancer cells in vitro and suppressed tumor growth in vivo.ConclusionsThese results suggest that ApoC-I peptides may be a potential diagnostic biomarker and therapeutic approach for BC.

Application of SELDI-TOF in N-glycopeptides profiling of the urine from patients with endometrial, ovarian and cervical cancer

Purpose: Endometrial (ECa), ovarian (OCa) and cervical (CCa) cancers are among 10 of the most common cancers affecting women worldwide. Cancers are known to cause some proteins to be differentially glycosylated or aberrantly excreted in the urine, which can be used as biomarkers. Since ECa, OCa and CCa are difficult to diagnose at the early stage, the aim of the present study was to identify a panel of new biomarkers for early detection of the cancers using surface-enhanced laser desorption/ionization-time-of-flight (SELDI-TOF) technology. Identification of early biomarkers that are specific and efficient can increase the survival rate of the patients. Experimental design: Digested urinary proteins from patients with ECa, OCa and CCa were incubated on the champedak mannose-binding (CMB) lectin-immobilized PS10 chip. The lectin-captured glycopeptides were detected with SELDI-TOF mass spectrometry and followed by biomarker wizard analysis. Results: Peaks m/z 1201 and 1449 were detected as potential group discriminators. The peak m/z 1201 could distinguish OCa from CCa and ECa and its sensitivity and specificity were 100%. For m/z 1449, it was able to differentiate ECa from the other two types of cancer. Conclusions: The findings of this study suggest urinary glycopeptides m/z 1201 and 1449 may serve as potential biomarkers for the early detection of ECa, OCa and CCa, although this requires further extensive validation on clinically representative populations.

Novel possibilities in the study of the salivary proteomic profile using SELDI-TOF/MS technology.

There is currently an increasing interest in exploring human saliva to identify salivary diagnostic and prognostic biomarkers, since the collection of saliva is rapid, non-invasive and stress-free. Diagnostic tests on saliva are common and cost-effective, particularly for patients who need to monitor their hormone levels or the effectiveness of undergoing therapies. Furthermore, salivary diagnostics is ideal for surveillance studies and in situations where fast results and inexpensive technologies are required. The most important constituents of saliva are proteins, the expression levels of which may be modified due to variations of the cellular conditions. Therefore, the different profile of proteins detected in saliva, including their absence, presence or altered levels, is a potential biomarker of certain physiological and/or pathological conditions. A promising novel approach to study saliva is the global analysis of salivary proteins using proteomic techniques. In the present study, surface-enhanced laser desorption/ionization-time-of-flight/mass spectrometry (SELDI-TOF/MS), one of the most recent proteomic tools for the identification of novel biomarkers, is reviewed. In addition, the possible use of this technique in salivary proteomic studies is discussed, since SELDI technology combines the precision of matrix-assisted laser desorption/ionization-TOF/MS proteomic analysis and the high-throughput nature of protein array analysis.

Platelet proteomics in diagnostic differentiation of primary immune thrombocytopenia using SELDI-TOF-MS

BackgroundPrimary immune thrombocytopenic purpura (pITP) is defined as isolated autoimmune thrombocytopenia with idiopathic low platelet count, normal bone marrow, and unexplained causes of thrombocytopenia. Currently there is no definite criterion for ITP diagnosis. MethodsWe conducted proteomic screen of patients with pITP, secondary immune thrombocytopenia (sITP), and healthy controls using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). The proteomic profiles were obtained from platelet lysate samples of 82 healthy adult controls, 64 pITP, and 70 sITP patients, from which we screened marker proteins with significant differences, and constructed a diagnosis model using the artificial neural network (ANN) technique. ResultsWe identified 6 marker proteins in the platelet lysates of pITP patients. This diagnosis method differentiated pITP patients from sITP effectively with a sensitivity of 96.9% (31/32), a specificity of 71.0% (54/76), and the area under the ROC curve of 0.864 in the training set, and a sensitivity of 87.5% (28/32), a specificity of 69.7% (53/76), and a positive predictive value of 75.0% (81/108) in the test set. ConclusionThe artificial neural network model based on platelet protein profiling established a potential pITP diagnosis platform.

Screening and identification of post-traumatic stress-related serum factors in children with Wilms' tumors.

Wilms' tumors are one of the most common malignant, solid intra-abdominal tumors observed in children. Although potential tumor markers have been found, inflammatory cytokines interfere with the process of specific protein identification. The present study was undertaken to identify post-traumatic stress-related factors of Wilms' tumors and to verify the accuracy of early-stage tumor-specific serum protein markers. Serum samples were screened for differentially-expressed proteins using surface-enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF-MS). Potential markers were isolated and purified using solid-phase extraction (SPE) and SDS-PAGE. Following enzymatic digestion of the protein samples, the peptide fragments were detected with high performance liquid chromatography-mass spectrometry. The obtained peptide mass fingerprint was searched in the Swiss-Prot protein sequence database via the Mascot search engine. Differentially-expressed proteins were verified using western blot analysis. Differentially-expressed proteins with a mass/charge of 5,816 were screened out using SELDI-TOF-MS, and significant differences between the tumor and control groups, and the trauma and control groups were observed. Target proteins were isolated and purified using SPE and SDS-PAGE. Thioredoxin 1 (Trx1) was found to be differentially expressed. In the serum of children with Wilms' tumors, there was an increase in the level of the post-traumatic stress-related inflammatory factor, Trx1, as compared with the normal control group. Thus, the results of this study indicate that Trx1 presents a potential post-traumatic stress-related factor of Wilms' tumors.

Identification of carboxyl terminal peptide of Fibrinogen as a potential serum biomarker for gastric cancer.

Gastric cancer (GC) is a very common disease worldwide where new serum biomarkers are urgently needed to improve their early diagnosis. In this study, we aim to search for the potential serum protein/peptide biomarkers of GC by using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). We first obtained the serum protein/peptide profiles from a training dataset including 30 patients with GC, 16 cases with chronic benign gastric disease (CGD), and 30 normal controls (CON) where 15 protein peaks were identified to exhibit the obvious deviation (P < 0.001, Wilcoxon rank sum test) among GC, CGD, and CON analyzed by Biomarker Wizard 3.1 software with three protein peaks with mass-to-charge (m/z) ratio 5910, 5342, and 6439 further confirmed in the validation dataset. Among the three protein peaks, peak 5910 displayed the most significantly different which could distinguish GC patients from CGD and CON with a sensitivity of 86.3%, a specificity of 91.3%, and the area under the receiver operating characteristic curve (AUC) of 0.89 by using the optimal cutoff value of 17.3. We further identified peak 5910 as the carboxyl terminal fraction of Fibrinogen α by LC-MS and validated its identity by antiserum-mediated SELDI-based immunodepletion assays. In sum, SELDI-TOF-MS method could effectively generate serum peptidome in cancer patients and provide a new approach to identify potentially diagnostic and prognostic biomarkers for cancer. The carboxyl terminal fraction of Fibrinogen α may be a potential serological biomarker for GC diagnosis.

Protein expression in dairy cows with and without subclinical hypocalcaemia

AIM: To determine differences in plasma proteomic profiles between healthy cows and those with subclinical hypocalcaemia within 12 hours after calving, and thereby explore the underlying biological mechanism of subclinical hypocalcaemia in dairy cows.METHODS: Plasma samples were collected within 6 hours of calving from Holstein cows on a farm in Heilongjiang, China; 32 with subclinical hypocalcaemia (plasma calcium concentration 1.38–2.00 mmol/L and no clinical signs) and 59 control cows (plasma calcium concentration 2.10–2.8 mmol/L). Plasma samples were applied to weak cationic exchange protein chips for protein profiling by surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (SELDI-TOF-MS), and the data were analysed using the PBS-IIC system. The amplitude of peaks for the two groups were compared using the Wilcoxon sum-rank test, and the mass-to-charge ratio of the peaks that differed was used to identify peptide fragments using the Swiss-Prot protein database.RESULTS: Seven peaks were identified in the subclinical hypocalcaemia group that differed from those of the control group (p<0.001), that represented six unique proteins. Expression of serum albumin, fibrinogen alpha chain, amyloid beta A4 proteins and neurosecretory protein VGF were increased, and expression of apolipoprotein A-II and serum amyloid A proteins were decreased in the subclinical hypocalcaemic cows compared with control cows.CONCLUSION: Use of SELDI-TOF-MS technology can effectively identify differences in plasma protein expression patterns in cows with subclinical hypocalcaemia. Neurosecretory protein VGF and amyloid beta A4 protein might represent useful biomarkers for diagnosis of subclinical hypocalcaemia.

A SELDI-TOF approach to ecotoxicology: comparative profiling of low molecular weight proteins from a marine diatom exposed to CdSe/ZnS quantum dots

Quantum dots (QDs), namely semiconductor nanocrystals, due to their particular optical and electronic properties, have growing applications in device technology, biotechnology and biomedical fields. Nevertheless, the possible threat to human health and the environment have attracted increasing attention as the production and applications of QDs increases rapidly while standard evaluation of safety lags.In the present study we performed proteomic analyses, by means of 2D gel electrophoresis and Surface Enhanced Laser Desorption Ionization-Time of Flight-Mass Spectrometry (SELDI-TOF-MS). We aimed to identify potential biomarkers of exposure to CdSe/ZnS quantum dots. The marine diatom Phaeodactylum tricornutum exposed to 2.5nM QDs was used as a model system. Both 2DE and SELDI showed the presence of differentially expressed proteins. By Principal Component Analysis (PCA) we were able to show that the differentially expressed proteins can discriminate between exposed and not exposed cells. Furthermore, a protein profile specific for exposed cells was obtained by SELDI analysis. To our knowledge, this is the first example of the application of SELDI technology to the analysis of microorganisms used as biological sentinel model of marine environmental pollution.

Mass spectral analysis of urine proteomic profiles of dairy cows suffering from clinical ketosis

Background: Ketosis is an important metabolic disorder in dairy cows during the transition period. The urine proteomics of ketosis has not been investigated using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS).Objective: The aim is to determine differences between urine proteomic profiles of healthy cows and those with clinical ketosis, and facilitate studies of the underlying physiological and biochemical mechanisms that lead to liver pathology in ketosis.Animals and methods: We analyzed the urine samples of 20 cows with clinical ketosis (group 1) and 20 control cows (group 2) using SELDI-TOF-MS.Results: Thirty-nine peptide peaks differed between both groups. Polypeptides corresponding to 26 of these differential peptide peaks were identified using the SWISS-PROT protein database. We found that the peaks of 11 distinct polypeptides from the urine samples of the ketosis group were significantly reduced, compared with those of the control group as based on the Wilcoxon rank sum test. Among these were VGF (non-acronymic) protein, amyloid precursor protein, serum amyloid A (SAA), fibrinogen, C1INH, apolipoprotein C-III, cystatin C, transthyretin, hepcidin, human neutrophil peptides, and osteopontin.Conclusion: These proteins may represent novel biomarkers of the metabolic changes that occur in dairy cows with ketosis. Our results will help to better understand the physiological changes and pathogenesis observed in cows with ketosis.Clinical importance: The SELDI-TOF-MS can be used to understand the physiological and biochemical mechanisms of ketosis and identify biomarkers of the disease.

Differential expression and clinical significance of serum protein among patients with clear-cell renal cell carcinoma

Looking for tumor markers by using protein chip technology is one of the hot topics, but many studies are still limited on short term detection of differential expressed proteins before and after surgery among patients with RCC. This study analyzed differential expressed serum protein and its clinical significance with clear-cell renal cell carcinoma to further measurement of the rule of variable expressing. Eighty-nine patients with clear-cell renal cell carcinoma who underwent surgery from November 2013 to 2014 and postoperatively confirmed by pathology were entered in RCC group, 100 healthy volunteers and patients without RCC who underwent medical examination in the same period were entered in control group. The serum protein were analyzed in both group before surgery and every regular follow-up period in 1 year after surgery with RCC group. The surface-enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS) and weak cation exchange protein chip (CM10) technology systems were used for identifying differential expressed serum protein in RCC group and controls. The linear support vector machine (SVM) was applied to establish the diagnostic model of protein fingerprints and the leave-one-out cross validation was used for determining model discriminating effect. The differential expressed proteins were analyzed by ZUCI-PDAS protein spectral data analysis system. Five kinds of proteins were identified as potential biomarker, ultimately. The M/Z of these proteins was 15953, 7987, 9304, 8948, 5911, respectively. There were significant difference on expression level of these proteins with two groups preoperatively (P< 0.05). Comparison of all postoperative expression levels to preoperative one and each differential level mutually between a year in postoperative period also revealed statistical significance (P< 0.05). With taking identified proteins as biomarker, the sensitivity and specificity in predicting clear-cell renal cell carcinoma was 88.8% (79/89) and 91.0% (91/100), respectively. The corresponding specific protein was Bcl-2 family apoptosis regulatory proteins, WAP four-disulfide core protein, Krueppel-like factor 8, monocyte chemotactic protein-1, serum amyloid β -protein-4, respectively, and will may serve as tumor markers of kidney cancer. These proteins manifests high predictive value for clear-cell renal cell carcinoma, and may contribute to therapeutic evaluation, prognosis and targeted therapy for clear-cell renal cell carcinoma.