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[Display omitted] Anticancer peptides (ACPs) are promising antitumor drugs owning to their great cancer cell targeting and anticancer effects as well as low drug resistance. However, many of the ACPs have non-specific toxicity and can be easily degraded by the enzymes after administration. Therefore, drug delivery systems (DDSs) are required to shield these peptides from degradation and induce targeted delivery. In this paper, a high performance microfluidic device was used to fabricate the zeolitic imidazolate framework (ZIF-8) encapsulating an ACP (At3) recently developed by our group. The microfluidic device allowed for efficient and rapid mixing to generate ACP loaded nanoparticles (NPs) with controllable properties at high production rate (120 mL/min) and high encapsulation efficiency. The ZIF-8 NPs synthesised by microfluidic processing showed lower polydispersity index (PDI) than the conventional method, demonstrating an improved size uniformity. Encapsulating At3 into the ZIF-8 (At3@ZIF-8) significantly reduced the hemolytic effect and provided a pH-controlled release of At3 peptide. At3@ZIF-8 showed higher anticancer effect than the unloaded peptide at the same concentration due to the enhanced cell uptake by the ZIF-8 NPs. The NPs were able to inhibit the growth of the multicellular tumour spheroids (MCTSs) and damage the mitochondrial membrane of the MCF-7 breast cancer cells. In vivo experiments demonstrated that the At3@ZIF-8 NPs inhibited the growth of MCF-7 tumours in nude mice without changing the biochemical properties of the blood or the histopathological properties of vital organs. Therefore, the development of At3 loaded NPs provides an alternative approach in ACP delivery which can broaden the application of ACP-based cancer therapy. [ABSTRACT FROM AUTHOR]

Nonspecific adsorption of non-target components (especially proteins) in food matrix on sensing surfaces deteriorates accuracy and sensitivity of electrochemical sensors, which is a key challenge for food safety sensing. Therefore, electrochemical sensors with antifouling capability of high-protein food matrices are highly desired. In this paper, an efficient and simple antifouling electrochemical aptasensor for tetracycline (TC) analysis was constructed based on a self-designed Y-shaped peptide [CPPPPEK-(RSERSERSE) 2 ] consisting of cysteine as the anchoring segment, polyproline as the supporting segment, and -EK-(RSERSERSE) 2 as antifouling branches. Hydrophilic and electrically neutral amino acid sequence and Y-shaped space structure of the peptide endow the sensing surface with good antifouling performance in protein solutions and diluted milk. Under optimized experiment conditions, the proposed aptasensor can detect TC with a wide linear range (0.01–100 ng mL−1) and a limit of detection of 5.3 pg mL−1 (S/N = 3). The spiked recovery experiments confirmed high accuracy of the aptasensor in diluted milk without other pretreatments (recoveries: 90.96%–95.86%). This strategy offers a valid way to reduce matrix interference, showing a promise to be extended to other sensing systems for different targets. [Display omitted] • An innovative electrochemical aptasensor was developed for TC determination. • It consists of CPPPPEK-(RSERSERSE) 2 and specific aptamer. • The Y-shaped peptide endowed the aptasensor with excellent antifouling ability. • The proposed sensor has satisfactory selectivity, repeatability and stability. [ABSTRACT FROM AUTHOR]

Insects have about 50 neuropeptide genes and about 70 genes, coding for neuropeptide G protein-coupled receptors (GPCRs). An important, but small family of evolutionarily related insect neuropeptides consists of adipokinetic hormone (AKH), corazonin, and AKH/corazonin-related peptide (ACP). Normally, insects have one specific GPCR for each of these neuropeptides. The tick Ixodes scapularis is not an insect, but belongs to the subphylum Chelicerata, which comprises ticks, scorpions, mites, spiders, and horseshoe crabs. Many of the neuropeptides and neuropeptide GPCRs occurring in insects, also occur in chelicerates, illustrating that insects and chelicerates are evolutionarily closely related. The tick I. scapularis is an ectoparasite and health risk for humans, because it infects its human host with dangerous pathogens during a blood meal. Understanding the biology of ticks will help researchers to prevent tick-borne diseases. By annotating the I. scapularis genome sequence, we previously found that ticks contain as many as five genes, coding for presumed ACP receptors. In the current paper, we cloned these receptors and expressed each of them in Chinese Hamster Ovary (CHO) cells. Each expressed receptor was activated by nanomolar concentrations of ACP, demonstrating that all five receptors were functional ACP receptors. Phylogenetic tree analyses showed that the cloned tick ACP receptors were mostly related to insect ACP receptors and, next, to insect AKH receptors, suggesting that ACP receptor genes and AKH receptor genes originated by gene duplications from a common ancestor. Similar duplications have probably occurred for the ligand genes, during a process of ligand/receptor co-evolution. Interestingly, chelicerates, in contrast to all other arthropods, do not have AKH or AKH receptor genes. Therefore, the ancestor of chelicerates might have lost AKH and AKH receptor genes and functionally replaced them by ACP and ACP receptor genes. For the small family of AKH, ACP, and corazonin receptors and their ligands, gene losses and gene gains occur frequently between the various ecdysozoan clades. Tardigrades, for example, which are well known for their survival in extreme environments, have as many as ten corazonin receptor genes and six corazonin peptide genes, while insects only have one of each, or none. [Display omitted] • The tick Ixodes scapularis is a vector for serious human diseases, such as Lyme. • G protein-coupled receptors (GPCRs) play a central role in the physiology of ticks. • GPCRs are also excellent drug targets to fight ticks. • Ticks have as many as five possible GPCR genes for the tick neuropeptide ACP. • We cloned these GPCRs and deorphanized them as being ACP receptors. [ABSTRACT FROM AUTHOR]

• In this study, we propose the first novel predictor named AAPred-CNN based on deep learning models and embedding techniques for the classification of AAP, attempting to apply deep model into this field and make improvements on the precondition performance. • AAPred-CNN is derived from TextCNN (Text Convolution Neural Network), adpoting multiple convolution channels to extract the local features of the input sequences. • Comparative results show that AAPred-CNN outperforms the state-of-the-art methods in all evaluation metrics and gains a remarkable improvement. • Notably, AAPred-CNN can work well even though only hundreds of training samples are given, which is intuitive. Recently, deep learning techniques have been developed for various bioactive peptide prediction tasks. However, there are only conventional machine learning-based methods for the prediction of anti-angiogenic peptides (AAP), which play an important role in cancer treatment. The main reason why no deep learning method has been involved in this field is that there are too few experimentally validated AAPs to support the training of deep models but researchers have believed that deep learning seriously depends on the amounts of labeled data. In this paper, as a tentative work, we try to predict AAP by constructing different classical deep learning models and propose the first deep convolution neural network-based predictor (AAPred-CNN) for AAP. Contrary to intuition, the experimental results show that deep learning models can achieve superior or comparable performance to the state-of-the-art model, although they are given a few labeled sequences to train. We also decipher the influence of hyper-parameters and training samples on the performance of deep learning models to help understand how the model work. Furthermore, we also visualize the learned embeddings by dimension reduction to increase the model interpretability and reveal the residue propensity of AAP through the statistics of convolutional features for different residues. In summary, this work demonstrates the powerful representation ability of AAPred-CNNfor AAP prediction, further improving the prediction accuracy of AAP. [ABSTRACT FROM AUTHOR]

Illustration of Zn2+ induced formation of spheric aggregates at mid-pH for cellular entry. [Display omitted] Although the restriction of intramolecular motion has been well recognized as the fundamental of aggregation induced emission enhancement (AIEE), the regulation mechanism of gold nanoclusters (AuNCs) based AIEE system are still unclear. In this paper, we have investigated the Zn2+-induced AIEE process of thiolate ligands (i.e., cysteine, glutathione and an 8-mer peptide) protected AuNCs, which shows a pH-dependent evolution from single AuNCs to spheric aggregates to irregular network. Using photoluminescent enhancement ratio as an index, the concept of " mid-pH " is proposed to indicate the optimal pH for the formation of spheric AuNCs aggregates. Importantly, the surface ligands allow the formation of spheric AuNCs aggregates at tunable mid-pH between 5.7 and 7.5. Owing to the appropriate size and surface peptide targetability, the spheric AuNCs aggregates can be successfully screened for targeted tumor cell uptake and imaging at physiological pH. The cell uptake mechanism study showed that AuNCs aggregates was specifically recognized by arginine-glycine-aspartic acid (RGD) sequence on the ligand and integrin αvβ3 on the cell surface, thus mainly through clathrin-mediated endocytosis. This work provides new sight to artificially regulate the construction of efficient cellular imaging probes. [ABSTRACT FROM AUTHOR]

A systematic scattering investigation of R5 (SSKKSGSYSGKSGSKRRIL) peptides establishes that self-assembly of large aggregates occurs due to phosphate bridging and at elevated ionic strengths. Static light scattering, small angle X-ray and small angle neutron scattering measurements reveal peptides conform into spheres with radius ~1 nm which assemble into large mass-fractal aggregates. Further, R5 aggregates are found to act as nucleation sites for the condensation of silicic acid oligomers while phosphate ions assist in driving bio-silification. [Display omitted] Despite advances in understanding the R5 (SSKKSGSYSGKSGSKRRIL) peptide-driven bio-silica process, there remains significant discrepancies regarding the physicochemical characterization and the self-assembling mechanistic driving forces of the supramolecular R5 template. This paper investigates the self-assembly of R5 as a function of monovalent (sodium chloride) and multivalent salt (phosphate) to determine if assembly is phosphate ion concentration dependent. Additionally, we hypothesize that the assembled R5 aggregates do not resemble a micelle or unimer structure as proposed in current literature. R5 peptides were synthesized, and aggregates evaluated for their size, morphology, and association state as a function of salt and ionic strength concentration via dynamic and static light scattering, small angle X-ray and neutron scattering and cryogenic transmission electron microscopy. Furthermore, we compare the proposed R5 template to precipitated silica by scanning electron microscopy. R5 peptides assemble into large aggregates due to multivalence bridging and the decrease in electrostatic repulsion due to ionic strength. We elucidate the structure of R5 aggregates as mass-fractals composed of small spherical aggregates. Moreover, we discover that phosphate ions not only have a significant role in driving the growth of the R5 scaffold, but additionally in driving the polycondensation of silicic acid during the bio-silification process via electrostatic interactions. [ABSTRACT FROM AUTHOR]

Although diabetic polyneuropathy (DPN) is the commonest diabetic complication, its pathology remains to be clarified. As previous papers have suggested the neuroprotective effects of glucagon-like peptide-1 in DPN, the current study investigated the physiological indispensability of glucagon gene-derived peptides (GCGDPs) including glucagon-like peptide-1 in the peripheral nervous system (PNS). Neurological functions and neuropathological changes of GCGDP deficient (gcg −/−) mice were examined. The gcg −/− mice showed tactile allodynia and thermal hyperalgesia at 12–18 weeks old, followed by tactile and thermal hypoalgesia at 36 weeks old. Nerve conduction studies revealed a decrease in sensory nerve conduction velocity at 36 weeks old. Pathological findings showed a decrease in intraepidermal nerve fiber densities. Electron microscopy revealed a decrease in circularity and an increase in g -ratio of myelinated fibers and a decrease of unmyelinated fibers in the sural nerves of the gcg −/− mice. Effects of glucagon on neurite outgrowth were examined using an ex vivo culture of dorsal root ganglia. A supraphysiological concentration of glucagon promoted neurite outgrowth. In conclusion, the mice with deficiency of GCGDPs developed peripheral neuropathy with age. Furthermore, glucagon might have neuroprotective effects on the PNS of mice. GCGDPs might be involved in the pathology of DPN. • Deficiency of glucagon gene-derived peptides (GCGDPs) caused peripheral neuropathy with age in mice. • GCGDPs might have neuroprotective effects on the peripheral nervous system of mice. • Glucagon promoted neurite outgrowth of dorsal root ganglion neurons. [ABSTRACT FROM AUTHOR]

Immunosuppressive domain (ISD) is a conserved region of transmembrane proteins (TM) in envelope gene ( env ) of retroviruses. in vitro and vivo, a synthetic peptide (CKS-17) that shows homology to ISD inhibits immune function. Evidence has shown that ISD suppresses lymphocyte proliferation and allows escape from immune effectors of the innate and adaptive arms in mouse immune system. Previously, we have developed a tool ISDTool 1.0 to identify ISD of human endogenous retrovirus (HERV). However, several other important retroviruses exist and no method is devoted to ISD prediction of them so far. In the paper, a computational model is proposed to identify ISD of six typical retroviruses from three species. The model combines the minimum Redundancy Maximum Relevance (mRMR) feature selection criterion with weighted extreme learning machine (WELM) to achieve high identification accuracies of 98.95%, 96.34% and 96.87% using self-consistency, 5-fold and 10-fold cross-validation, respectively. A software tool named ISDTool 2.0 has been developed to facilitate the application of the model and a large number of new putative ISDs of the six retroviruses were predicted. In addition, motifs of ISD in these retroviruses were analyzed and the evolutionary relationship was discussed. Datasets and the software involved in the paper are available at http://sourceforge.net/projects/isdtool/files/ISDTool-2.0/ . [ABSTRACT FROM AUTHOR]

Autophagy is a self-degradative process important for balancing the sources of energy and involved in the development of Alzheimer's disease (AD). To date, a number of papers have shown that elastin-derived peptides (EDPs) affect the expression and activation of peroxisome proliferator-activated receptor gamma (PPARγ), which is crucial for the development of AD and autophagy initiation. Therefore, the aim of the present study was to determine whether EDPs with a Val–Gly–Val–Ala–Pro–Gly (VGVAPG) amino acid sequence activate the autophagic process in undifferentiated SH-SY5Y human neuroblastoma cells. Our study is the first to show that EDPs with the VGVAPG sequence initiate the autophagy process in the undifferentiated SH-SY5Y cell line exhibiting a number of features of normal neuroblasts. In particular, we observed in our study that VGAVPG peptide increased ULK1, AKT, PPARγ, and LC3B protein expression. Moreover, our experiments with the agonist (rosiglitazone) and antagonist (GW9662) of PPARγ confirm that the studied EDP acts through the PPARγ pathway affecting mTOR and finally autophagy. Some studies have shown that autophagy disturbances are involved in the development of AD. Therefore, we believe that our study will provide new evidence of the possible involvement of EDPs (especially VGVAPG) in the development of AD. • The VGVAPG peptide induces autophagy in SH-SY5Y cells. • The VGVAPG peptide acts mainly through interacting with the PPARγ pathway. • The VGVAPG peptide does not initiate proliferation of undifferentiated SH-SY5Y cells. • The VGVAPG peptide increases ULK1, AKT, PPARγ, and LC3B protein expression. [ABSTRACT FROM AUTHOR]

Highlights • Theoretical minimal RNA rings recapitulate the order of the genetic code's codon-amino acid assignments. • The paper present theoretical minimak RNA rings produced by simulations in silico which suggest an ancestral frameless translation of partially overlapping trinucleotides advancing by single nucleotide steps, constrained by resource scarcity. • Minimal RNA rings reflect the transition from frameless to ribosomal translation and are realistic candidates for ancestral tRNAs. Abstract Background Theoretical minimal RNA rings form stem-loop hairpins coding for each of the 20 amino acids and a stop, presumably mimicking life's first minimal coding and self-replicating RNAs. They resemble consensual tRNAs. Mean amino acid positions in proteins follow the genetic code's consensual amino acid inclusion order, a 5′-late-to-3′-early amino acid gradient. Hypothesis We translated minimal RNA rings to test whether translated peptides share that gradient with modern proteins, using a) ribosomal translation, non-overlapping consecutive codons; and b) frameless translation advancing nucleotide by nucleotide, producing partially overlapping codons. Results For frameless translation, most RNA rings code for a 5′-late-to-3′early amino acid gradient. Gradients indicate decreasing amino acid metabolic costs, from large to small amino acids. For ribosomal translation, the 5′-late-to-3′early amino acid gradient evolves from early to late RNA rings when ranked according to yields in Miller's experiment of their predicted anticodon's cognate amino acid. Conclusions Simulations that produced in silico minimal RNA rings didn't account for coded amino acid properties. Yet, produced peptides remind actual proteins, and suggest ancestral frameless translation of partially overlapping trinucleotides advancing by single nucleotide steps, constrained by resource scarcity. Minimal RNA rings reflect the transition from frameless to ribosomal translation and are realistic candidates for ancestral tRNAs. [ABSTRACT FROM AUTHOR]

The abundance of B cell lymphoma gene 2 (Bcl-2) is closely correlated with the resistance of cancer cells to chemotherapeutic agents, and a peptide derived from orphan nuclear receptor Nur77 can convert Bcl-2 from a protector to a killer of cancer cells. However, successful application of the Bcl-2-converting peptide to treat drug-resistant cancer cells depends on an efficient delivery carrier. Mesoporous silica nanoparticles (MSNs) have been extensively studied as promising candidates for small molecule drug delivery. However, the effective encapsulation and intracellular delivery of peptides using small pore-sized MSNs still remain a great technical challenge. In this paper, an effective delivery platform for Bcl-2-converting peptide was fabricated by us to treat multidrug resistant-cancer cells via tuning the surface functionality of macroporous silica nanoparticles. The resulting large-sized pore silica nanoparticles, especially those modified with thiol group, exhibited the high Bcl-2-converting peptide-loading efficiency of over 40%. Moreover, the peptide induced MCF7/DOX cells into apoptotic status by penetrating cytomembrane into mitochondria and being bound with Bcl-2 to expose the BH3 domain with the aid of various surface functionalities-decorated MSNs. In particular, amine-modified surface of MSNs caused the greater influence on the cell apoptosis-inducing effects of peptide in comparison with other functionalities-modified ones. Taken together, our study, for the first time, demonstrates a special approach towards pore size and surface functionality-collectively modulated silica-based nanostructural material for effective delivery of bio-macromolecules (e.g., Bcl-2-converting peptide) to treat the multidrug resistant-cancer cells with elevated Bcl-2 levels. [ABSTRACT FROM AUTHOR]

Oxytocin (OXT) and arginine vasopressin (AVP) are structurally similar neuropeptide hormones that function as neurotransmitters in the brain, and have opposite key roles in social behaviors. These peptides bind to their G protein-coupled receptors (OXTR and AVPRs), inducing calcium ion-dependent signaling pathways and endocytosis of these receptors. Because selective agonists and antagonists for these receptors have been developed as therapeutic and diagnostic agents for diseases such as psychiatric disorders, facile methods are in demand for the evaluation of selectivity between these receptors. In this study, we developed a quantitative assay for OXT- and AVP-induced endocytosis of their receptors. The mutated Oplophorus luciferase, nanoKAZ, was fused to OXTR and AVPRs to enable rapid quantification of agonist-induced endocytosis by bioluminescence reduction. Agonist stimulation significantly decreases bioluminescence of nanoKAZ-fused receptors in living cells. Using this system, we evaluated clinically used OXTR antagonist atosiban and a reported pyrazinyltriazole derivative, hereby designated as PF13. Atosiban acted as an antagonist of AVPR1a, as well as an agonist for AVPR1b, whereas PF13 antagonized OXTR more selectively than atosiban, as reported previously. This paper shows a strategy for quantification of agonist-induced endocytosis of OXTR and AVPRs, and confirms its potent utility in the evaluation of agonists and antagonists. [ABSTRACT FROM AUTHOR]

In this paper, growth hormone releasing peptide-6 (GHRP-6) is a bioactive polypeptide and acts as the reducing agent and capping ligand for synthesis of bright green fluorescent gold nanoclusters (GHRP-6-Au NCs) by a simple and environmental-friendly aqueous method, with the assistance of NaBr as the fluorescent sensitizer. The obtained GHRP-6-Au NCs had high fluorescent quantum yield (10.7%), and the fluorescence was strongly quenched by the existence of trace Fe 3+ . Thus, a new and highly sensitive sensor for the assay of Fe 3+ was constructed based on the analyte-induced fluorescent quenching mechanism. The sensor had a low detection limit of 1.4 µM (S/N = 3) and a wide linear range of 2–1000 µM. Besides, GHRP-6-Au NCs exhibited low cytotoxicity and high biocompatibility for cell imaging. [ABSTRACT FROM AUTHOR]

The Radon transform is a potentially powerful tool for processing the data from serial spectroscopic experiments. It makes it possible to decode the rate at which frequencies of spectral peaks shift under the effect of changing conditions, such as temperature, pH, or solvent. In this paper we show how it also improves speed and sensitivity, especially in multidimensional experiments. This is particularly important in the case of low-sensitivity techniques, such as NMR spectroscopy. As an example, we demonstrate how Radon transform processing allows serial measurements of 15 N -HSQC spectra of unlabelled peptides that would otherwise be infeasible. [ABSTRACT FROM AUTHOR]

• Establish KOVAK system to detect antigen intermediates containing OVA-derived epitope. • Characterize profiles of antigen intermediates generated in living cells. • Reveal functions of molecular chaperones (e.g., TRiC and Hsp90) in the antigen processing pathway. Cytotoxic T lymphocytes recognize antigen-derived peptides (epitopes) bound to MHC class I presented on the cell surface of virus-infected cells and cancer cells. To date, numerous pathogen-derived epitopes and cancer cell-specific epitopes have been identified and used in the development of mRNA and peptide vaccines, but much remains unknown regarding the intracellular mechanisms that generate these antigen epitopes. These mechanisms are essential for cytotoxic T cell immunity. In this paper, I outline an innovation pioneered by Professor Nilabh Shastri and me, in which we developed a biochemical system to detect antigen intermediates and illuminated the role of molecular chaperones in antigen processing. [ABSTRACT FROM AUTHOR]

Skeletal remains of two equid species, Equus caballus (horse) and Equus asinus (donkey), have been found in archaeological contexts throughout Iberia since the Palaeolithic and Chalcolithic periods, respectively. These two species play different economic and cultural roles, and therefore it is important to be able to distinguish between the two species to better understand their relative importance in the past human societies. The most reliable morphological features for distinguishing between the two domesticated equids are based on cranial measurements and tooth enamel folds, leading to only a small percentage of archaeological remains that can be identified to species. Ancient DNA (aDNA) analysis can be used to reliably distinguish the two equids, but it can be cost prohibitive to apply to large assemblages, and aDNA preservation of non-cranial elements is often low. Collagen peptide mass fingerprinting by matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry, also known as zooarchaeology by mass spectrometry (ZooMS), is a minimally destructive and cost-effective alternative to aDNA analysis for taxonomic determination. However, current ZooMS markers lack resolution below the genus level Equus. In this paper, we report a novel ZooMS peptide marker that reliably distinguishes between horses and donkeys using the enzyme chymotrypsin. We apply this peptide marker to taxonomically identify bones from the Iberian Peninsula ranging from the Iron Age to the Late Modern Period. The peptide biomarker has the potential to facilitate the collection of morphological data for zooarchaeological studies of equids in Iberia and throughout Eurasia and Africa. • Novel ZooMS biomarker discriminates between horses and donkeys. • Novel biomarker provided species level identification for archaeological samples identified only to Equus. • The enzyme, chymotrypsin, reliably provides unique peptide markers for ZooMS analysis. [ABSTRACT FROM AUTHOR]

The discovery of a class of self-assembling peptides that spontaneously undergo self-organization into well-ordered structures opened a new avenue for molecular fabrication of biological materials. In this paper, the structure controlled helical nanofibers were prepared by two artificial β-sheet dipeptides with long alkyl chains derived from l - and d -threonine (Thr) and sodium hydroxide (NaOH). These helical nanofibers have been characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), circular dichroism (CD), Fourier transform infrared (FT-IR) spectroscopy, and X-ray powder diffraction (XRD). It was demonstrated that the helicity of the nanofibers could be easily controlled by changing the chirality of the constituent amino acids in the peptide species ( d - or l -threonine). Moreover, the hydrogen bonding interactions between the amide groups as well as the hydrophobic interactions among the alkyl chains play important roles in the self-assembly process. It also can be observed that with the passage of time, the hydrogen bonding interactions between the individual nanofiber induced the conversion from nanofibers to nanobelts. Particularly, gold and silver nanoparticles performed good catalytic ability were synthesized using the assembled nanofibers as template. [ABSTRACT FROM AUTHOR]

Bifidobacteria are gut commensal microorganisms belonging to the Actinobacteria group. Some specific strains of Bifidobacterium animalis subsp. lactis are used in functional foods as they are able to exert health-promoting effects in the human host. Due to the limited genetic variability within this subspecies, it is sometimes difficult for a manufacturer to properly track its strain once included in dairy products or functional foods. In this paper, we present a peptidome-based analysis in which the proteomes of a set of B. animalis subsp. lactis strains were digested in silico with human gut endopeptidases. The molecular masses were compared along all the strains to detect strain-specific peptides. These peptides may be interesting towards the development of methodologies for strain identification in the final product. [ABSTRACT FROM AUTHOR]

In this paper, the preparation, purification, and identification of the antioxidant peptides of millet gliadin after high hydrostatic pressure (HHP) treatment were studied to broaden the utilization range of millet and provide certain theoretical basis for its further processing and utilization. Millet gliadin treated with 300 MPa was enzymatically hydrolyzed by pepsin, and the optimal hydrolysis time was determined to be 50 min by in-vitro antioxidant activity evaluation method [1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical, hydroxyl radical, and superoxide anion scavenging activity]. The enzymatic hydrolysate was separated and purified by gel filtration and RP-HPLC, and the fraction with the strongest antioxidant activity (S4) was obtained. The scavenging ability of DPPH, •OH, and O 2 − were 53.96% ± 0.86%, 31.30% ± 0.90%, and 52.73% ± 0.99%, respectively. However, it still had lower antioxidant capacity compared with VC. Seven peptide sequences, namely, SLSHLTVQ, SLAHVTVQ, LHALTLQ, SGILAPSPVL, SHLTVQ, VSAAAA, and SPAAF, were identified from S4. The presence of certain amino acids, such as Glycine, Leucine, Phenylalanine, and Proline , is considered to induce high antioxidant activity against lipid peroxidation. Therefore, the antioxidant peptide extracted from millet gliadin after HHP treatment may be used as a natural antioxidant component in functional food. • HHP treatment significantly increased the enzymatic hydrolysis rate of millet gliadin. • The antioxidant peptide obtained had the strongest in-vitro activity after 300 MPa. • Seven novel antioxidant peptide sequences were identified and isolated. [ABSTRACT FROM AUTHOR]

Cyclotides are bioactive peptides from plants that are characterized by their head-to-tail cyclic backbone and knotted arrangement of their three conserved disulfide bonds. Their natural function is thought to be as host defense agents and a single plant can express dozens to hundreds of cyclotides. This article provides a brief overview of the history of the discovery of cyclotides and their applications in drug design and agriculture, the former based on their stability as a peptide scaffold and the latter based on their activity against crop pests. More than 300 papers have been published on cyclotides and they represent a promising field of biotechnological research. [ABSTRACT FROM AUTHOR]

[Display omitted] • Six Oreoch-2 analogues were designed and synthesized. • Their biological activities were evaluated systematically. • In particular, the antibacterial activity of ZN-5 and ZN-6 was twice as good as that of Oreoch-2. • In addition, ZN-5 and ZN-6 had much higher selectivity to bacteria cells than to eukaryotic cells. In recent years, bacterial resistance has risen sharply, which seriously endangers public health due to the abuse of antibiotics and the lack of new antibiotics. Therefore, there is an urgent need for new antimicrobial agents to combat multidrug-resistant (MDR) bacterial infections. In this paper, six Oreoch-2 analogues were rationally designed and efficiently synthesized by using the truncation strategy with Oreoch-2 as the lead compound. Evaluation of these analogues against a panel of Gram-positive and Gram-negative bacteria including MDR strains was performed. Among them, ZN-5 and ZN-6 were identified to be broad-spectrum effective analogues, which were superior to their parent peptide Oreoch-2. In addition, ZN-5 and ZN-6 had good stability to the physiological environment, and much higher selectivity to bacterial cells than to mammalian cells. Time-kill kinetics and transmission electron microscope (TEM) studies suggested that these analogues were typical bactericidal agents and quickly eliminated bacteria in a bactericidal mode by disrupting bacterial cell membrane. Moreover, ZN-5 and ZN-6 could inhibit biofilm formation of Staphylococcus aureus ATCC25923. Compared with their parent peptide Oreoch-2, ZN-5 and ZN-6 not only possessed shortened peptide chains, but also showed slightly improved antibacterial activity and greatly reduced hemolysis. This indicates that they are ideal lead compounds of antimicrobial peptides, which can be developed as substitutes for traditional antibiotics. [ABSTRACT FROM AUTHOR]

Whey protein is a fraction of milk protein that has both nutritional and health boosting effects. Hydrolyzation of whey protein by enzyme or fermentation can generate bioactive peptides that are beneficial to the life activities and/or regulate the physiological functions. Though whey protein has been widely applied in food industry, many newly developed whey protein peptide products with multiple bioactivities come up in commercial market or from research labs. In this paper, we systematically discussed the general production flow of whey peptides, newly found bioactive peptides from whey and their functions, the safety evaluation of those whey products containing mixed peptides as well as the typical whey protein peptide lactoferricin. Generally, whey hydrolyzed peptides can be safely used as food ingredients for functional foods, whereas specific purified whey peptide should be carefully evaluated before use in high quantities. • The general processing route of whey biopeptides was described. • Whey biopeptides have multiple beneficial functions. • Newly found whey biopeptides were summarily described. • Safety issues of using whey peptides in the food market were discussed. [ABSTRACT FROM AUTHOR]

The shelf-life of live oysters is a quality-concerned issue along with the supply chain of the products. In present study, mass spectrometry-based peptidomics has been employed to investigate changes of endogenous peptides of Pacific oysters (Crassostrea gigas) occurred during anhydrous preservation with the purpose of discovering shelf-life indicators of live oysters. Samples of Crassostrea gigas harvested freshly were acclimated to laboratory environment first and then put under defined anhydrous preservation conditions (being packaged in sterile plastic bags and stored at 4 ± 1 °C in low-temperature incubators). After regular intervals, samples were randomly collected for peptidomics analysis using ultra-high performance liquid chromatography-quadrupole/time-of-flight mass spectrometry and potential peptide markers were mined by chemometric tools and verified by a multi-reaction monitoring method with ultrahigh-performance liquid chromatography-triple quadrupole mass spectrometry. Approximately 8526 peptides, in total, were characterized and 4 endogenous peptides, SSSTGEVGTYSGTTN, TARNEANVNI, VGIIKGSSSEEA, and TARNEANVNIY, were finally proposed as potential markers for shelf-life evaluating. The proposed markers were applied to real-life samples and expected trends of the markers during anhydrous preservation were observed, implying applicability of the endogenous peptides for shelf-life evaluating. The findings of this study provide favorable evidences of mass spectrometry-based peptidomics in quality assessing for aquaculture products. • Potential of peptide markers for shelf-life of C. gigas was assessed. • 4 endogenous peptide markers were unveiled by MS-based peptidomics and chemometrics. • An MRM method with the potential markers for routine use was proposed. [ABSTRACT FROM AUTHOR]

This paper is aimed at examining the antibacterial and antioxidant properties of the hydrolysate of Terfezia claveryi protein by a mixture of trypsin and chymotrypsin in-vitro , identifying the potential peptides responsible for the observed effects. The hydrolysate was fractioned by ultrafiltration membranes to achieve the most efficient mentioned peptides and then the filtrate of less than 3-kDa was exposed to further purification by FPLC and RP-HPLC, respectively. VGDDLTVTNPLRIK, IGGIGTVPVGRVETG, and ELTGIPPAPR were the sequence of more active fraction evaluated by LC-MS/MS. Moreover, raw milk was applied to prove the potential of hydrolysate as a natural preservative. The results suggested that the tested fractions had a dose-dependent inhibitory effect on some bacteria of raw milk including total, coliform and psychrotrophic bacteria and by lesser extent, on lactic acid bacteria. However, the more purified fraction had less effect on sensory characteristics. • Terfezia claveryi's peptides produced by intestinal proteases had antioxidant and antibacterial properties. • Smaller peptides were more bioactive than larger ones. • Peptides with the most efficient antioxidant and antibacterial properties were sequenced. • Some peptides had inhibitory effect on some bacteria of raw milk. [ABSTRACT FROM AUTHOR]

At present, the identification of amyloid becomes more and more essential and meaningful. Because its mis-aggregation may cause some diseases such as Alzheimer's and Parkinson's diseases. This paper focus on the classification of amyloidogenic peptides and a novel feature representation called PhyAve_PSSMDwt is proposed. It includes two parts. One is based on physicochemical properties involving hydrophilicity, hydrophobicity, aggregation tendency, packing density and H-bonding which extracts 15-dimensional features in total. And the other is 60-dimensional features through recursive feature elimination from PSSM by discrete wavelet transform. In this period, sliding window is introduced to reconstruct PSSM so that the evolutionary information of short sequences can still be extracted. At last, the support vector machine is adopted as a classifier. The experimental result on Pep424 dataset shows that PSSM's information makes a great contribution on performance. And compared with other existing methods, our results after cross-validation increase by 3.1%, 3.3%, 0.136 and 0.007 in accuracy, specificity, Matthew's correlation coefficient and AUC value, respectively. It indicates that our method is effective and competitive. • A feature representation called PhyAve_PSSMDwt is applied to identify amyloidogenic peptides. • We introduce sliding windows so that the evolutionary information on PSSM can still be extracted from short sequence. • PhyAve_PSSMDwt model outperforms some other existing methods. [ABSTRACT FROM AUTHOR]