Lysophosphatidic acid contributes to myocardial ischemia/reperfusion injury by activating TRPV1 in spinal cord.

Lysophosphatidic acid (LPA) is a bioactive phospholipid that plays a crucial role in cardiovascular diseases. Here, we question whether LPA contributes to myocardial ischemia/reperfusion (I/R) injury by acting on transient receptor potential vanilloid 1 (TRPV1) in spinal cord. By ligating the left coronary artery to establish an in vivo I/R mouse model, we observed a 1.57-fold increase in LPA level in the cerebrospinal fluid (CSF). The I/R-elevated CSF LPA levels were reduced by HA130, an LPA synthesis inhibitor, compared to vehicle treatment (4.74 ± 0.34 vs. 6.46 ± 0.94 µg/mL, p = 0.0014). Myocardial infarct size was reduced by HA130 treatment compared to the vehicle group (26 ± 8% vs. 46 ± 8%, p = 0.0001). To block the interaction of LPA with TRPV1 at the K710 site, we generated a K710N knock-in mouse model. The TRPV1K710N mice were resistant to LPA-induced myocardial injury, showing a smaller infarct size relative to TRPV1WT mice (28 ± 4% vs. 60 ± 7%, p < 0.0001). Additionally, a sequence-specific TRPV1 peptide targeting the K710 region produced similar protective effects against LPA-induced myocardial injury. Blocking the K710 region through K710N mutation or TRPV1 peptide resulted in reduced neuropeptides release and decreased activity of cardiac sensory neurons, leading to a decrease in cardiac norepinephrine concentration and the restoration of intramyocardial pro-survival signaling, namely protein kinase B/extracellular regulated kinase/glycogen synthase kinase-3ß pathway. These findings suggest that the elevation of CSF LPA is strongly associated with myocardial I/R injury. Moreover, inhibiting the interaction of LPA with TRPV1 by blocking the K710 region uncovers a novel strategy for preventing myocardial ischemic injury.

Discovery of Elaphuri Davidiani Cornu-specific peptide biomarkers by peptidomics analysis-based method.

Elaphuri Davidiani Cornu (EDC) is the antler of the male Père David's deer, which has been reported to have multiple biological activities, and its use as a traditional Chinese medicine (TCM) in China has been known for thousands of years. However, EDC is difficult to distinguish from other related species-derived antlers in powder or extract form in TCM clinic use, such as Cervus elaphus Cornu (CEC) and Cervus nippon Cornu (CNC), both derived from Cervidae and easily confused with EDC. In this study, a strategy using peptidomics combined with mathematics set analysis was used to identify EDC-specific peptide biomarkers, and four specific peptide biomarkers (Pep-E1-E4) were identified and validated. Pep-E1, Pep-E3, and Pep-E4 could be exclusively detected in EDC samples, with relative peak areas of 0.298 ± 0.060, 0.039 ± 0.015, and 0.037 ± 0.008, whereas Pep-E2 showed relative peak area of 0.516 ± 0.101 in EDC, 0.132 ± 0.026 in CEC, and 0.136 ± 0.047 in CNC samples, respectively. These four peptides are applicable to distinguish EDC from CEC and CNC, which is of great significance for the quality control of EDC.

Ubiquitin-specific peptide 22 acts as an oncogene in gastric cancer in a son of sevenless 1-dependent manner.

BACKGROUND: Aberrant expression of ubiquitin-specific peptide 22 (USP22) has been detected in various cancers. This study aimed to investigate the role of USP22 and the underlying mechanism in human gastric cancer. METHODS: The expression pattern of USP22 in human gastric cancer was detected in a tissue microarray containing 88 pairs of gastric cancer tissue and adjacent normal tissue samples from patients with primary gastric cancer using immunohistochemical staining. The correlation of USP22 expression with clinical characteristics of patients, as well as their prognostic values in the overall survival of patients, were evaluated. USP22-overexpressing SGC7901 and USP22-silencing AGS cells were used to explore the role of USP22 in gastric cancer cell behavior in vitro and in vivo. Chromatin immunoprecipitation was performed to identify differentially expressed genes induced by USP22 overexpression. Western blot analysis was conducted to detect the activation of RAS/ERK and PI3K/AKT signaling in USP22-overexpressing SGC7901 cells and xenograft tumor tissues. Knockdown of RAS activator son of sevenless 1 (SOS1) was performed to investigate the role of SOS1 in USP22-regulated gastric cancer cell behavior and RAS signaling both in vitro and in vivo. RESULTS: USP22 protein expression was significantly increased in human gastric cancer tissues, compared with adjacent normal tissues, and was positively correlated with local tumor stage. Gain- and loss-of-function assays showed that USP22 promoted gastric cancer cell growth and cell cycle transition while suppressing apoptosis in vitro. Consistent results were observed in a xenograft mouse model. Chromatin immunoprecipitation revealed that the overexpression of USP22 induced the upregulation of RAS activator son of sevenless 1 (SOS1) in SGC7901 cells. Western blot analysis showed that USP22 overexpression also induced activation of the RAS/ERK and PI3K/AKT pathways in SGC7901 cells and xenograft tumor tissues. Furthermore, SOS1 silencing could reverse the effects of USP22 on gastric cancer cell behavior and RAS signaling both in vitro and in vivo. CONCLUSIONS: Our results suggest that USP22 acts as an oncogene in gastric cancer in a SOS1-dependent manner, identifying the USP22/SOS1/RAS axis as a potential therapeutic target in gastric cancer.

A modification-specific peptide-based immunization approach using CRM197 carrier protein: Development of a selective vaccine against pyroglutamate Aß peptides.

Strategies aimed at reducing cerebral accumulation of the amyloid-ß (Aß) peptides have therapeutic potential in Alzheimer's disease (AD). Aß immunization has proven to be effective at promoting Aß clearance in animal models but adverse effects have hampered its clinical evaluation. The first anti-Aß immunization clinical trial, which assessed a full-length Aß1-42 vaccine, increased the risk of encephalitis most likely because of autoimmune pro-inflammatory T helper 1 (Th1) response against all forms of Aß. Immunization against less abundant but potentially more pathologically relevant Aß products, such as N-terminally-truncated pyroglutamate-3 Aß (AßpE3), could provide efficacy and improve tolerability in Aß immunotherapy. Here, we describe a selective vaccine against AßpE3, which uses the diphtheria toxin mutant CRM197 as carrier protein for epitope presentation. CRM197 is currently used in licensed vaccines and has demonstrated excellent immunogenicity and safety in humans. In mice, our AßpE3:CRM197 vaccine triggered the production of specific anti-AßpE3 antibodies that did not cross-react with Aß1-42, non-cyclized AßE3, or N-terminally-truncated pyroglutamate-11 Aß (AßpE11). AßpE3:CRM197 antiserum strongly labeled AßpE3 in insoluble protein extracts and decorated cortical amyloid plaques in human AD brains. Anti-AßpE3 antibodies were almost exclusively of the IgG1 isotype, suggesting an anti-inflammatory Th2 response bias to the AßpE3:CRM197 vaccine. To the best of our knowledge, this study shows for the first time that CRM197 has potential as a safe and suitable vaccine carrier for active and selective immunization against specific protein sequence modifications or conformations, such as AßpE3.

Evaluation of Chemical Interactions between Small Molecules in the Gas Phase Using Chemical Force Microscopy.

Chemical force microscopy analyzes the interactions between various chemical/biochemical moieties in situ. In this work we examined force-distance curves and lateral force to measure the interaction between modified AFM tips and differently functionalized molecular monolayers. Especially for the measurements in gas phase, we investigated the effect of humidity on the analysis of force-distance curves and the images in lateral force mode. Flat chemical patterns composed of different functional groups were made through micro-contact printing and lateral force mode provided more resolved analysis of the chemical patterns. From the images of 1-octadecanethiol/11-mercapto-1-undecanoic acid patterns, the amine group functionalized tip brought out higher contrast of the patterns than an intact silicon nitride tip owing to the additional chemical interaction between carboxyl and amine groups. For more complex chemical interactions, relative chemical affinities toward specific peptides were assessed on the pattern of 1-octadecanethiol/phenyl-terminated alkanethiol. The lateral image of chemical force microscopy reflected specific preference of a peptide to phenyl group as well as the hydrophobic interaction.

Discrimination of three commercial tuna species through species-specific peptides: From high-resolution mass spectrometry discovery to MRM validation.

The risk of tuna adulteration is high driven by economic benefits. The authenticity of tuna is required to protect both consumers and tuna stocks. Given this, the study is designed to identify species-specific peptides for distinguishing three commercial tropical tuna species. The peptides derived from trypsin digestion were separated and detected using ultrahigh-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) in data-dependent acquisition (DDA) mode. Venn analysis showed that there were differences in peptide composition among the three tested tuna species. The biological specificity screening through the National Center for Biotechnology Information's Basic Local Alignment Search Tool (NCBI BLAST) revealed that 93 peptides could serve as potential species-specific peptides. Finally, the detection specificity of species-specific peptides of raw meats and processed products was carried out by multiple reaction monitoring (MRM) mode based on a Q-Trap mass spectrometer. The results showed that three, one and two peptides of Katsuwonus pelamis, Thunnus obesus and Thunnus albacores, respectively could serve as species-specific peptides.

Identification and application of species-specific peptide biomarkers from soft-shelled turtles (Pelodiscus sinensis) using post-translational modification detection-based peptidomics analysis.

The soft-shelled turtle is a commercially aquatic species in Asian countries, which serves as an important source of collagen with high nutritional and medicinal value, so it is of great significance to distinguish soft-shelled turtle derived collagen from others or adulterations. In this work, peptidomics analysis based on post-translational modification (PTM) assay was used to discover specific peptide biomarkers of soft-shelled turtle gelatin (STG). In total eight specific sequences and 74 peptides with different PTM types were screened out, and seven peptides with good signal responses and STG specificity were selected and validated as STG-specific peptide biomarkers. These peptide biomarkers could be used for distinguishing STG from other animal gelatins, and applied for ensuring the quality of collagens or gelatins from soft-shelled turtle with authenticity and traceability.

Biopanning of specific peptide for SARS-CoV-2 nucleocapsid protein and enzyme-linked immunosorbent assay-based antigen assay.

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread worldwide which triggered serious public health issues. The search for rapid and accurate diagnosis, effective prevention, and treatment is urgent. The nucleocapsid protein (NP) of SARS-CoV-2 is one of the main structural proteins expressed and most abundant in the virus, and is considered a diagnostic marker for the accurate and sensitive detection of SARS-CoV-2. Herein, we report the screening of specific peptides from the pIII phage library that bind to SARS-CoV-2 NP. The phage monoclone expressing cyclic peptide N1 (peptide sequence, ACGTKPTKFC, with C&C bridged by disulfide bonding) specifically recognizes SARS-CoV-2 NP. Molecular docking studies reveal that the identified peptide is bound to the "pocket" region on the SARS-CoV-2 NP N-terminal domain mainly by forming a hydrogen bonding network and through hydrophobic interaction. Peptide N1 with the C-terminal linker was synthesized as the capture probe for SARS-CoV-2 NP in ELISA. The peptide-based ELISA was capable of assaying SARS-CoV-2 NP at concentrations as low as 61 pg/mL (∼1.2 pM). Furthermore, the as-proposed method could detect the SARS-CoV-2 virus at limits as low as 50 TCID50 (median tissue culture infective dose)/mL. This study demonstrates that selected peptides are powerful biomolecular tools for SARS-CoV-2 detection, providing a new and inexpensive method of rapidly screening infections as well as rapidly diagnosing coronavirus disease 2019 patients.

Discovery of specific antioxidant peptide from Chinese Dahe black pig and hybrid pig dry-cured hams based on peptidomics strategy.

The quality of hams obtained from different pig breeds can vary depending on endogenous antioxidant peptides in the hams. The aims of this study were (i) to investigate the specific peptides in Chinese Dahe black pig ham (DWH) and hybrid pig ham (Yorkshire × Landrace × Dahe black ham, YLDWH) and their antioxidant activity, and (ii) to elucidate the relationship between ham quality and antioxidant peptides. iTRAQ quantitative peptidomic method was used to discover specific peptides of DWH and YLDWH. In addition, in vitro assays were performed to evaluate their antioxidant activity. A total of 73 specific peptides were identified from DWH and YLDWH by LC-MS/MS. Forty-four specific peptides in DWH were primarily hydrolysed from myosin and myoglobin by endopeptidases, while 29 specific peptides in YLDWH were primarily hydrolysed from myosin and troponin-T. Six specific peptides that were statistically significantly different based on their fold changes and P-values were selected for the identification of DWH and YLDWH. DWH-derived specific peptide AGAPDERGPGPAAR (AR14), which had high stability and was non-toxic, had the highest DPPH• and ABTS•+ scavenging activity (IC50 = 1.657 mg/mL and 0.173 mg/mL, respectively) and cellular antioxidant capacity. Molecular docking showed that AR14 interacted with Val369, and Val420 of Keap1 via hydrogen bonds. Furthermore, AR14 bound to DPPH and ABTS through hydrogen bonding and hydrophobic interactions. Together, our results demonstrate that the DWH-derived antioxidant peptide AR14 exhibits the free radical scavenging and cellular antioxidant activity and can be used to preserve ham quality and promote human health.

Blapstin, a Diapause-Specific Peptide-Like Peptide from the Chinese Medicinal Beetle Blaps rhynchopetera, Has Antifungal Function.

Drug resistance against bacteria and fungi has become common in recent years, and it is urgent to discover novel antimicrobial peptides to manage this problem. Many antimicrobial peptides from insects have been reported to have antifungal activity and are candidate molecules in the treatment of human diseases. In the present study, we characterized an antifungal peptide named blapstin that was isolated from the Chinese medicinal beetle Blaps rhynchopetera used in folk medicine. The complete coding sequence was cloned from the cDNA library prepared from the midgut of B. rhynchopetera. It is a 41-amino-acid diapause-specific peptide (DSP)-like peptide stabilized by three disulfide bridges and shows antifungal activity against Candida albicans and Trichophyton rubrum with MICs of 7 µM and 5.3 µM, respectively. The C. albicans and T. rubrum treated with blapstin showed irregular and shrunken cell membranes. In addition, blapstin inhibited the activity of C. albicans biofilm and showed little hemolytic or toxic activity on human cells and it is highly expressed in the fat body, followed by the hemolymph, midgut, muscle, and defensive glands. These results indicate that blapstin may help insects fight against fungi and showed a potential application in the development of antifungal reagents. IMPORTANCE Candida albicans is one of the conditional pathogenic fungi causing severe nosocomial infections. Trichophyton rubrum and other skin fungi are the main pathogens of superficial cutaneous fungal diseases, especially in children and the elderly. At present, antibiotics such as amphotericin B, ketoconazole, and fluconazole are the main drugs for the clinical treatment of C. albicans and T. rubrum infections. However, these drugs have certain acute toxicity. Long-term use can increase kidney damage and other side effects. Therefore, obtaining broad-spectrum antifungal drugs with high efficiency and low toxicity for the treatment of C. albicans and T. rubrum infections is a top priority. Blapstin is an antifungal peptide which shows activity against C. albicans and T. rubrum. The discovery of blapstin provides a novel clue for our understanding of the innate immunity of Blaps rhynchopetera and provides a template for designing antifungal drugs.

Identification of Characteristic Peptides of Casein in Cow Milk Based on MALDI-TOF MS for Direct Adulteration Detection of Goat Milk.

It is widely acknowledged that casein is an important allergenic protein in milk which may cause danger to customers. The identification and confirmation of caseins through mass spectrometry requires the selection of suitable characteristic peptides. In this study, by means of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), the three most representative specific peptides of caseins in cow milk were screened out with mass-to-charge ratios (m/z) of 830, 1195, and 1759, respectively. By comparing 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA) MALDI matrices, it was found that DHB was more suitable for peptide detection with the limits of detection (LODs) of 0.1 mg/L for α, ß-casein. Furthermore, on the basis of verifying the characteristic peptides of casein from cow milk, this protocol was applied to goat milk authentication. Cow milk addition in goat milk was investigated by using the screened specific peptides. The results showed that the adulteration could be identified when the proportion of cow milk was 1% or more. When applied to inspect adulteration in five brands of commercial goat milk, specific peptides of bovine casein were detected in four of them. The method has the advantages of strong reliability, high throughput, simple preprocessing, and fast speed, which can provide powerful help for prewarning dairy allergen.

Electrochemical sensor for human norovirus based on covalent organic framework/pillararene heterosupramolecular nanocomposites.

Noroviruses are the leading cause of acute gastroenteritis and food-borne diseases worldwide. Thus, a rapid, accurate, and easy-to-implement detection method for controlling infection and monitoring progression is urgently needed. In this study, we constructed a novel sandwich-type electrochemical biosensor integrated with two specific recognition elements (aptamer and peptide) for human norovirus (HuNoV). The electrochemical biosensor was fabricated using magnetic covalent organic framework/pillararene heterosupramolecular nanocomposites (MB@Apt@WP5A@Au@COF@Fe3O4) as the signal probes. The sensor showed high accuracy and selectivity. The detection method does not need the extraction and amplification of virus nucleic acid and has a short turn-around time. Intriguingly, the proposed biosensor had a limit of detection of 0.84 copy mL-1 for HuNoV, which was the highest sensitivity among published assays. The proposed biosensor showed higher sensitivity and accuracy compared with immunochromatographic assay in the detection of 98 clinical specimens. The biosensor was capable of determining the predominant infection strain of GII.4 and also GII.3 and achieved 74% selectivity for HuNoV GII group. This study provides a potential method for point-of-care testing and highlights the integrated utilization of Apt and peptide in sensor construction.

A novel screening on the specific peptide by molecular simulation and development of the electrochemical immunosensor for aflatoxin B1 in grains.

In this work, based on a specific antibody was obtained from the Protein Data Bank (PDB), a library of the specific peptides of aflatoxin B1 (AFB1) was constructed by combining key amino acids, amino acid mutations and molecular docking. Then, the porous gold nanoparticles (porous AuNPs) were fabricated on the surface of a glassy carbon electrode (GCE). A novel, sensitive and no-label signal immunosensor was developed by signal enhancement with the specific peptide as the recognition element for the detection of AFB1 in cereals. Under the optimal conditions, the limit of detection (S/N = 3) was 9.4 × 10-4 µg·L-1, and the linear range was 0.01 µg·L-1 to 20 µg·L-1. The recovery results were 88.4%∼102.0%, which indicated an excellent accuracy. This sensor is an ideal candidate for screening the peptides of AFB1, and a novel immunosensor was used to detect AFB1 in cereals.

A quantitative method for detecting meat contamination based on specific polypeptides.

OBJECTIVE: This study was aimed to establish a quantitative detection method for meat contamination based on specific polypeptides. METHODS: Thermally stable peptides with good responses were screened by high resolution liquid chromatography tandem mass spectrometry. Standard curves of specific polypeptide were established by triple quadrupole mass spectrometry. Finally, the adulteration of commercial samples was detected according to the standard curve. RESULTS: Fifteen thermally stable peptides with good responses were screened. The selected specific peptides can be detected stably in raw meat and deep processed meat with the detection limit up to 1% and have a good linear relationship with the corresponding muscle composition. CONCLUSION: This method can be effectively used for quantitative analysis of commercial samples.

NSCs Migration Promoted and Drug Delivered Exosomes-Collagen Scaffold via a Bio-Specific Peptide for One-Step Spinal Cord Injury Repair.

Spinal cord injury (SCI) is plaguing medical professionals globally due to the complexity of injury progression. Based on tissue engineering technology, there recently emerges a promising way by integrating drugs with suitable scaffold biomaterials to mediate endogenous neural stem cells (NSCs) to achieve one-step SCI repair. Herein, exosomes extracted from human umbilical cord-derived mesenchymal stem cells (MExos) are found to promote the migration of NSCs in vitro/in vivo. Utilizing MExos as drug delivery vehicles, a NSCs migration promoted and paclitaxel (PTX) delivered MExos-collagen scaffold is designed via a novel dual bio-specificity peptide (BSP) to effectively retain MExos within scaffolds. By virtue of the synergy that MExos recruit endogenous NSCs to the injured site, and PTX induce NSCs to give rise to neurons, this multifunctional scaffold has shown superior performance for motor functional recovery after complete SCI in rats by enhancing neural regeneration and reducing scar deposition. Besides, the dual bio-specific peptide demonstrates the capacity of tethering other cells-derived exosomes on collagen scaffold, such as erythrocytes-derived or NSCs-derived exosomes on collagen fibers or membranes. The resulting exosomes-collagen scaffold may serve as a potential multifunctional therapy modality for various disease treatments including SCI.

Bio-vehicles of cytotoxic drugs for delivery to tumor specific targets for cancer precision therapy.

Abnormal structural and molecular changes in malignant tissues were thoroughly investigated and utilized to target tumor cells, hence rescuing normal healthy tissues and lowering the unwanted side effects as non-specific cytotoxicity. Various ligands for cancer cell specific markers have been uncovered and inspected for directional delivery of the anti-cancer drug to the tumor site, in addition to diagnostic applications. Over the past few decades research related to the ligand targeted therapy (LTT) increased tremendously aiming to treat various pathologies, mainly cancers with well exclusive markers. Malignant tumors are known to induce elevated levels of a variety of proteins and peptides known as cancer "markers" as certain antigens (e.g., Prostate specific membrane antigen "PSMA", carcinoembryonic antigen "CEA"), receptors (folate receptor, somatostatin receptor), integrins (Integrin αvß3) and cluster of differentiation molecules (CD13). The choice of an appropriate marker to be targeted and the design of effective ligand-drug conjugate all has to be carefully selected to generate the required therapeutic effect. Moreover, since some tumors express aberrantly high levels of more than one marker, some approaches investigated targeting cancer cells with more than one ligand (dual or multi targeting). We aim in this review to report an update on the cancer-specific receptors and the vehicles to deliver cytotoxic drugs, including recent advancements on nano delivery systems and their implementation in targeted cancer therapy. We will discuss the advantages and limitations facing this approach and possible solutions to mitigate these obstacles. To achieve the said aim a literature search in electronic data bases (PubMed and others) using keywords "Cancer specific receptors, cancer specific antibody, tumor specific peptide carriers, cancer overexpressed proteins, gold nanotechnology and gold nanoparticles in cancer treatment" was carried out.

Fluorescence detection of histamine based on specific binding bioreceptors and carbon quantum dots.

Histamine is primarily found in spoiled food and often used as an indicator of food safety. Compared to various existing methods for analyzing histamine, high-performance liquid chromatography (HPLC) which is accurate but time-consuming, and immunochemical methods that are difficult to produce high specificity and affinity antibodies towards small molecules have been used. In this study, we developed a newly designed, sensitive, and selective fluorescence detection platform for histamine sensing, utilizing carbon quantum dots (CQDs) and synthetic peptides. Specifically, through biopanning approaches, a series of peptides having a high affinity towards immobilized histamine hapten were selected from phage-displayed libraries. Then, CQDs were synthesized by one-pot hydrothermal treatment enabling their fluorescence to be effectively quenched by peptides via the electron transfer interactions. While, in the presence of histamine, fluorescence will be recovered because of the stronger interaction between peptide and target. In this study, from the selectivity tests towards histamine and in contrast to structurally similar compounds, peptide Hisp3 (DIDRAGKASHWP) along with its dipeptide repeat derivative (Hisp3-2-C) were chemically synthesized to be used as promising histamine receptors. Furthermore, the application of peptide along with gold-coated magnetic nanoparticles (MNP@Au NPs) was designed for purification and analysis of fish samples. These results indicate that the CQDs and peptide sensor system could detect histamine at lower concentrations with high sensitivity and selectivity.

A strategy for identifying species-specific peptide biomarkers in deer-hide gelatin using untargeted and targeted mass spectrometry approaches.

Deer-hide gelatin (DHG) is an important animal-derived traditional Chinese medicine (TCM), which has been applied in TCM for over 400 years. However, it is extremely difficult to distinguish DHG with adulteration or made with other animal skins due to the highly processing procedure. Therefore, a simple strategy for identifying species-specific peptide biomarkers in deer-hide gelatin (DHG) is needed. In the present study, untargeted and targeted mass spectrometry approaches were implemented to analyze comprehensive peptidomic profiles of trypsin-digested animal gelatins. Mathematics set theory was then used to interrogate the relationship between different samples and peptides in the target species set, while the peptides were not considered as species-specific biomarkers in other sets. Two peptides were identified as DHG-specific peptides. Targeted mass spectrometry approach was then used to verify these two peptides. It showed that these two peptides could be used for distinguishing DHG from other animal hide gelatins. The present strategy provides a simple method for peptide biomarker discovery, which can be applied in the identification of specific peptides in some highly processed animal derived traditional Chinese medicines (TCMs). Thus, the present work provides an effective strategy for rapid, simple discovery and application of species-specific peptide biomarkers to ensure animal derived TCMs quality and make them authenticable and traceable.

Electrochemical and optical investigation of dental pulp stem cell adhesion on modified porous silicon scaffolds.

Extensive use of porous silicon (PSi) for tissue engineering is due to its convenient properties as it is both nontoxic and bioresorbable. Moreover, PSi surface modification is an important step to enhance cell adhesion and proliferation. In this work, a combination of optical and electrochemical studies is performed to elaborate a suitable PSi multilayer substrate for cell culture. For this study, we modified PSi surface by silanization and antibody grafting (APTES-anti STRO1), the 12-mer specific peptide to silicon p + type coating and the peptide modified with the antibody recognition sequence. Electrochemical characterization of PSi multilayers is performed to investigate its electrical behavior, determine the optimal measuring conditions and reveal the most stable PSi surfaces. Then, the behavior of dental pulp stem cells (DPSC) was investigated on various modified PSi surfaces. An electrochemical method was applied for the first time monitoring the electrical behavior of stem cell adhesion. The cells electrochemical behavior depends on the nature of the surface coating and the peptide-anti STRO1 improved adhesion and cell spreading onto the PSi surface compared to bare surface and the one coated with the peptide. Fluorescent microscopy revealed that all surface modification methods enhance cell adhesion compared to the bare PSi surface. An increased cell number is observed on APTES-anti STRO1, peptide and peptide-anti STRO1 coated PSi. The peptide-anti STRO1 provided the best cell proliferation results suggesting the improved accessibility of the recognition fragment of the antibody anti-STRO1.

Authentication of Edible Bird's Nest (EBN) and its adulterants by integration of shotgun proteomics and scheduled multiple reaction monitoring (MRM) based on tandem mass spectrometry.

Edible bird's nest (EBN) has been traditionally regarded as a kind of medicinal and healthy food in Asia. However, economically motivated adulteration (EMA) has been an issue in the EBN supply chain. To develop an accurate high-throughput approach for detecting EBN and its adulterants (exemplified by porcine skin, swim bladder, white fungus, and egg white), shotgun proteomics was applied for discovery of specific peptides that were subsequently converted into scheduled multiple reaction monitoring (MRM) transitions. Totally, 28 specific peptides were verified as unique to EBN and its adulterants by tandem mass spectrometry. Subsequently, 9 quantitative MRM-transitions of peptides from adulterants and 2 internal standard references from EBN were screened for the quantitative analysis of the adulterants, which allowed detection of adulterants in EBN matrix in the range of 1-80%. These results suggested that integration of shotgun proteomics and scheduled MRM had potential for the authentication of EBN and its adulterants.