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Proteomic analysis of the human body is a significant recent scientific endeavour. In this study, we investigated the proteomic profile of human dentin using modern analytical and mass spectrometric techniques. Five healthy permanent human molars from five adults were cut, pulverized, denaturated with guanidine buffer, and demineralized with EDTA buffer. The extracted proteins were analysed by gel electrophoresis (SDS-PAGE and two-dimensional gel electrophoresis), digested with trypsin, and separated by liquid chromatography/high-resolution tandem mass spectrometry. We identified 289 proteins with high confidence, 90 of which had not been previously detected in human dentin. Nine (currently hypothetical) proteins were identified for the first time in an actual human sample. The proteins have a variety of functions, including calcium-ion binding, formation of the extracellular matrix, formation of the cytoskeleton, cytoskeletal protein binding, immune response, and transport. In conclusion, this is the first use of two-dimensional electrophoresis for investigating human dentin.

The dentin–enamel junction (DEJ) is the border where two different mineralized structures – enamel and dentin – meet. The protein‐rich DEJ, together with the inner enamel region of mature teeth, is known to exhibit higher fracture toughness and crack growth resistance than bulk phase enamel. However, an explanation for this behavior has been hampered by the lack of compositional information for the DEJ and the adjacent enamel organic matrix (EOM). We studied proteomes of the DEJ and EOM of healthy human molars and compared them with dentin and enamel proteomes from the same teeth. These tissues were cut out of tooth sections by laser capture microdissection, proteins were extracted and cleaved by trypsin, then processed by liquid chromatography coupled to tandem mass spectrometry to analyze the proteome profiles of these tissues. This study identified 46 proteins in DEJ and EOM. The proteins identified have a variety of functions, including calcium ion‐binding, formation of extracellular matrix, formation of cytoskeleton, cytoskeletal protein binding, cell adhesion, and transport. Collagens were identified as the most dominant proteins. Tissue‐specific proteins, such as ameloblastin and amelogenin, were also detected. Our findings reveal new insight into proteomics of DEJ and EOM, highly mineralized tissues that are obviously difficult to analyze.

RationaleAvenanthramides (AVNs) are constituents unique to oats and have many outstanding health benefits. AVNs are antioxidants and possess anti‐inflammatory, antifungal and antibacterial activity. The number of known AVNs increased recently because of the latest developments in high‐resolution tandem mass spectrometry (HRMS/MS) techniques.MethodsOat seed extract from 10 oat cultivars was analysed using ultra‐high‐performance liquid chromatography (UHPLC) and Q Exactive hybrid quadrupole‐Orbitrap mass spectrometry (HRMS/MS) with positive heated electrospray ionization.ResultsThirty‐five AVNs were identified and characterized in seed extracts, and the structures of 10 novel AVNs were tentatively elucidated, among which were AVNs bearing a cinamoyl or sinapoyl moiety. These AVNs are reported in oats for the first time. The method was validated using AVN standards (AVNs 2c, 2f and 2p), with limits of detection and quantitation at low picomole levels. Recovery of AVN standards varied from 83% to 106%, and relative standard deviations ranged from 2% to 9%. The total AVNs in the selected oat varieties ranged from 36.0 to 302.5 μg/g (dry weight), with AVN 2c, AVN 2f and AVN 2p representing approximately 65%–70% of that total.ConclusionsOur comprehensive method for detecting the full avenanthramide spectrum can contribute to better understanding the chemical and biological properties of individual AVNs for utilization in developing new oat cultivars and novel functional foods.

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Colabomycin E is a new member of the manumycin-type metabolites produced by the strain Streptomyces aureus SOK1/5-04 and identified by genetic screening from a library of streptomycete strains. The structures of colabomycin E and accompanying congeners were resolved. The entire biosynthetic gene cluster was cloned and expressed in Streptomyces lividans. Bioinformatic analysis and mutagenic studies identified components of the biosynthetic pathway that are involved in the formation of both polyketide chains. Recombinant polyketide synthases (PKSs) assembled from the components of colabomycin E and asukamycin biosynthetic routes catalyzing the biosynthesis of "lower" carbon chains were constructed and expressed in S. aureus SOK1/5-04 ΔcolC11-14 deletion mutant. Analysis of the metabolites produced by recombinant strains provided evidence that in both biosynthetic pathways the length of the lower carbon chain is controlled by an unusual chain-length factor supporting biosynthesis either of a triketide in asukamycin or of a tetraketide in colabomycin E. Biological activity assays indicated that colabomycin E significantly inhibited IL-1β release from THP-1 cells and might thus potentially act as an anti-inflammatory agent.

Opioid addiction is recognized as a chronic relapsing brain disease resulting from repeated exposure to opioid drugs. Cellular and molecular mechanisms underlying the ability of organism to return back to the physiological norm after cessation of drug supply are not fully understood. The aim of this work was to extend our previous studies of morphine-induced alteration of rat forebrain cortex protein composition to the hippocampus. Rats were exposed to morphine for 10 days and sacrificed 24 h (groups +M10 and −M10) or 20 days after the last dose of morphine (groups +M10/−M20 and −M10/−M20). The six altered proteins (�2-fold) were identified in group (+M10) when compared with group (−M10) by twodimensional fluorescence difference gel electrophoresis (2D-DIGE). The number of differentially expressed proteins was increased to thirteen after 20 days of the drug withdrawal. Noticeably, the altered level of α-synuclein, β-synuclein, α-enolase and glyceraldehyde-3phosphate dehydrogenase (GAPDH) was also determined in both (±M10) and (±M10/ −M20) samples of hippocampus. Immunoblot analysis of 2D gels by specific antibodies oriented against α/β-synucleins and GAPDH confirmed the data obtained by 2D-DIGE analysis. Label-free quantification identified nineteen differentially expressed proteins in group (+M10) when compared with group (−M10). After 20 days of morphine withdrawal (±M10/−-M20), the number of altered proteins was increased to twenty. We conclude that the morphine-induced alteration of protein composition in rat hippocampus after cessation of drug supply proceeds in a different manner when compared with the forebrain cortex. In forebrain cortex, the total number of altered proteins was decreased after 20 days without morphine, whilst in hippocampus, it was increased.

Teeth have been a focus of interest for many centuries – due to medical problems with them. They are the hardest part of the human body and are composed of three mineralized parts – enamel, dentin and cementum, together with the soft pulp. However, saliva also has a significant impact on tooth quality. Proteomic research of human teeth is now accelerating, and it includes all parts of the tooth. Some methodological problems still need to be overcome in this research field – mainly connected with calcified tissues. This review will provide an overview of the current state of research with focus on the individual parts of the tooth and pellicle layer as well as saliva. These proteomic results can help not only stomatology in terms of early diagnosis, identifying risk factors, and systematic control.