The present invention relates to the field of identifying proteins and peptides, and more specifically large-scale sequencing of single peptides in a mixture of diverse peptides at the single molecule level. The present invention also relates to methods for identifying amino acids in peptides, including peptides comprising unnatural amino acids. In one embodiment, the present invention contemplates labeling the N-terminal amino acid with a first label and labeling an internal amino acid with a second label. In some embodiments, the labels are fluorescent labels. In other embodiments, the internal amino acid is Lysine. In other embodiments, amino acids in peptides are identified based on the fluorescent signature for each peptide at the single molecule level.

A panel of metabolic biomarkers for differential diagnosis of stable angina pectoris and acute coronary syndrome is published herein. The panel comprises one or more of the metabolic biomarkers, including malic acid, taurine, arachidonic acid, citramalic acid, methionine, pentadecanoic acid. Single use of the 6 differential metabolites provided clinically diagnostic value of SA vs. ACS with AUC>0.7. When combined, the more metabolites, the larger of AUC. The highest AUC of 0.987 was obtained when all of the six metabolites were combined to distinguish SA vs. ACS with sensitivity 96.8% and specificity 97.7% using optimal cut-off value. The metabolic biomarkers provided by the invention can be used for differential diagnosis of SA vs. ACS of high accuracy, sensitivity and specificity.

Disclosed herein, inter alia, are compositions and methods of use thereof for interrogating a cell.

In various embodiments methods are provided for identifying and/or quantifying one or more antigens of interest (biomarkers) on the surface of cell- or tissue-specific exosomes. In an illustrative embodiments the methods comprise: i) incubating a population of exosomes with one or more tissue-specific antibodies that bind an antigen specific to a tissue or cell type of interest that produces exosomes, where the tissue specific antibodies are attached to acceptor bead or magnetic beads so the antibodies bind exosomes displaying the antigen; ii) obtaining a purified population of exosomes bound by the tissue specific antibodies with and/or without photocleavable linker based technology; iii) incubating a test subset of the isolated tissue-specific exosomes with acceptor beads attached to test antibodies that bind an antigen of interest thereby binding exosomes that display the antigen of interest and a control subset with negative control acceptor beads; v) incubating the test subset of isolated exosomes and the control subset of exosomes with a donor-bearing antibody that binds an exosome specific antigen; and vi) detecting a signal produced upon illumination of the control subset and/or the test; and vii) detecting the antigen(s) of interest.

The present invention relates a method for the diagnosis, prediction or risk stratification for mortality and/or disease outcome of a subject that has or is suspected to have sepsis, comprising determining the presence and/or level of antitrypsin (ATT) or fragments thereof in a sample taken from said subject and/or determining the presence and/or level of transthyretin (TTR) or fragments thereof, wherein the presence and/or level of ATT and/or TTR or fragments thereof is correlated with an increased risk of mortality and, wherein said increased risk of mortality and/or poor disease outcome is given if the level of ATT is below a certain cut-off value and/or the level of fragments thereof is above a certain cut-off value and/or said increased risk of mortality and/or poor disease outcome is given if the level of TTR is below a certain cut-off value and/or the level of fragments thereof is below a certain cut-off value. The invention relates in general to the use of ATT and/or TTR or its fragments for the diagnosis of sepsis, and to nucleotides of SEQ ID NO. 2 to 14.

Electrophoretic separation methods and systems for performing the same are provided. The methods and systems find use in a variety of different electrophoretic separation applications, such as sub-cellular Western blotting of single cells.

The invention relates to a method for determining the presence of at least one distinct polypeptide in a biological sample comprising contacting the biological sample with a hydrolyzing agent, wherein the hydrolyzing agent is capable of hydrolyzing the distinct polypeptide in a sequence-specific manner such that at least one distinct peptide having a predetermined peptide measured accurate mass would result if the at least one distinct polypeptide were present in the biological sample, to obtain a hydrolyzed sample; bringing the hydrolyzed sample in contact with a substrate comprising at least one immobilized binding partner, wherein the at least one immobilized binding partner is capable of specifically binding the distinct peptide; removing the hydrolyzed sample from the substrate in a manner such that the distinct peptide would remain bound to the immobilized binding partner; contacting the substrate with an elution solution, wherein the distinct peptide would dissociate from the immobilized binding partner into the elution solution; subjecting a portion of the elution solution to liquid chromatography to segregate a plurality of molecules in the portion of the elution solution to obtain sorted molecules; determining the measured accurate mass of at least one sorted molecule present in the elution solution; and determining the presence of the at least one distinct polypeptide in the biological sample when a measured accurate mass of at least one molecule is substantially equal to the predetermined peptide measured accurate mass.

The present invention relates to a disease-specific metabolite profile, and particularly to a biomarker composition obtained by screening from urine-specific metabolite profiles of coronary heart disease subjects. The present invention also relates to a use of the biomarker compositions in risk assessment, diagnosis, early diagnosis, or pathological staging of coronary heart disease, and to a method for risk assessment, diagnosis, early diagnosis, or pathological staging of coronary heart disease. The biomarker composition as provided by the present invention can be used for early diagnosis of coronary heart disease and has high sensitivity, good specificity and good application prospects.

The invention provides methods for identifying biomarkers in a patient's microbiota to predict a patient's response to a predetermined diet to promote weight loss and methods of promoting weight loss or treating obesity in the patient by optimizing the patient's diet in accordance with the biomarkers identified in the patient's gut microbiota. The methods of the invention can also be used to manage or maintain weight, i.e., prevent or inhibit weight gain, in a patient who is of normal weight or is overweight or obese.

Methods and apparatus for the in vitro modelling of changes that occur on administration of a drug formulation are described, in particular for studying the changes that take place on administration of protein or peptide drug formulations by subcutaneous injection.