Protein hydrolysates in animal nutrition：Industrial production, bioactive peptides,and functional significance

Recent years have witnessed growing interest in the role of peptides in animal nutrition. Chemical, enzymatic, or microbial hydrolysis of proteins in animal by-products or plant-source feedstuffs before feeding is an attractive means of generating high-quality small or large peptides that have both nutritional and physiological or regulatory functions in livestock, poultry and fish. These peptides may also be formed from ingested proteins in the gastrointestinal tract, but the types of resultant peptides can vary greatly with the physiological conditions of the animals and the composition of the diets. In the small intestine, large peptides are hydrolyzed to small peptides,which are absorbed into enterocytes faster than free amino acids（AAs） to provide a more balanced pattern of AAs in the blood circulation. Some peptides of plant or animal sources also have antimicrobial, antioxidant,antihypertensive, and immunomodulatory activities. Those peptides which confer biological functions beyond their nutritional value are called bioactive peptides. They are usually 2–20 AA residues in length but may consist of 〉20AA residues. Inclusion of some（e.g. 2–8%） animal-protein hydrolysates（e.g., porcine intestine, porcine mucosa,salmon viscera, or poultry tissue hydrolysates） or soybean protein hydrolysates in practical corn-and soybean mealbased diets can ensure desirable rates of growth performance and feed efficiency in weanling pigs, young calves,post-hatching poultry, and fish. Thus, protein hydrolysates hold promise in optimizing the nutrition of domestic and companion animals, as well as their health（particularly gut health） and well-being.

A modified soft docking method for proteins and peptides

A modified two-stage soft-docking procedure was developed for the theoretic researches on the recognition of protein-protein or protein-peptide complexes. Some systems have been used to test our program and the results are encouraging.

Effects of Three Humic Acid Foliar Fertilizers on Quality and Photosynthetic Characteristics of Hawthorn

[Objectives]To investigate the effects of three foliar fertilizers on photosynthetic characteristics,fruit quality and yield of hawthorn.[Methods]Taking hawthorn foliar fertilization as the reference,the photosynthetic rate,transpiration rate,intercellular CO 2 concentration,stomatal conductance and single fruit weight of hawthorn leaves were measured under different concentrations of foliar fertilizer.[Results]The results showed that the photosynthetic rate,transpiration rate and stomatal conductance of hawthorn leaves increased significantly,while the intercellular CO 2 concentration decreased.Specifically,the fish protein peptide foliar fertilizer performed best,with net photosynthetic rate and transpiration rate increased by 57.22%and 57.51%,respectively.All the three foliar fertilizers significantly reduced the intercellular CO 2 concentration.In addition,fertilization significantly increased the single fruit weight of hawthorn,and the effect of fermented fulvic acid foliar fertilizer was the most significant,with the highest growth rate of 68.49%.[Conclusions]Spraying foliar fertilizer significantly increased the content of Vc,titratable acid,anthocyanin and soluble solids of hawthorn fruit,among which fermented fulvic acid foliar fertilizer had the optimal effect.

Peptide aptamer-mediated modulation of prion protein α-cleavage as treatment strategy for prion and other neurodegenerative diseases

Despite intensive research,most neurodegenerative diseases cannot be cured and for some of them no treatment is available to increase survival or quality of life.Among the latter are prion diseases,fatal and transmissible neurodegenerative diseases of humans and other animals.

Enhancing the treatment effects of tumor cell purified autogenous heat shock protein 70-peptide complexes on HER-3-overexpressing breast cancer

Objective The aim of this study was to enhance the treatment effect of tumor purified autogenous heat shock protein 70-peptide complexes(HSP70-PCs)on HER-3-overexpressing breast cancer.Methods In this study,we first studied the expression of HER-3 in breast cancer tissues and its relationship with patient characteristics.We then purified HSP70-PCs from primary breast cancer cells with different HER-2 and HER-3 expression profiles and determined the cytotoxicity of autogenous dendritic cells(DCs)and CD8+T cells induced by these complexes.Third,recombinant human HSP70-HER-3 protein complexes were used to inhibit the autogenous HSP70-PCs purified from HER-3-overexpressing breast cancer cells,and the resulting immunological response was examined.Results The results show that HSP70-PCs can be combined with recombinant HSP70-HER-3 protein complexes to induce stronger immunological responses than autogenous HSP70-PCs alone and that these treatments induce autogenous CD8+T cell killing of HER-3-positive breast cancer cells.Conclusion These findings provide a new direction for HSP70-DC-based immunotherapy for patients with HER-3-overexpressing breast cancer.

PLGA-based implants for sustained delivery of peptides/proteins:Current status,challenge and perspectives

Peptide and protein drugs with therapeutic effects suffer from their short half-life and low stability,albeit their high efficiency and specificity.To overcome these demerits,long-acting drug delivery systems have been developed,wherein poly(lactic-co-glycolic acid)(PLGA)implants are most preferred owing to their excellent biodegradability and biocompatibility.Dozens of PLGA based products have been approved since1986,when the first product,named Decapeptyl R,successfully marched into market.To meet the increasing demand for delivering various peptides and proteins,different kinds of technologies have been developed for lab-scale fabrication or industrial manufacture.This review aims to introduce recent advances of PLGA implants,and give a brief summary of fundamental properties of PLGA,fabrication technologies of peptides/proteins-loaded PLGA implants as well as factors influencing the drug release processes.Moreover,challenges and future perspectives are also highlighted.

Prophylactic Antitumor Effect of Mixed Heat Shock Proteins/Peptides in Mouse Sarcoma

Background：To develop a vaccine-based immunotherapy for sarcoma,we evaluated a mixture of heat shock proteins （mHSPs） as a vaccine for sarcoma treatment in a mouse model.Heat shock protein/peptides （HSP/Ps） are autoimmune factors that can induce both adaptive and innate immune responses;HSP/Ps isolated from tumors can induce antitumor immune activity when used as vaccines.Methods：In this study,we evaluated the effects of mHSP/Ps on prophylactic antitumor immunity.We extracted mHSP/Ps,including HSP60,HSP70,GP96,and HSP l 10,from the mouse sarcoma cell lines S 180 and MCA207 using chromatography.The immunity induced by mHSP/Ps was assessed using flow cytometry,ELISPOT,lactate dehydrogenase release,and enzyme-linked immunosorbent assay.Results：Of S180 sarcoma-beating mice immunized with mHSP/Ps isolated from S180 cells,41.2% showed tumor regression and long-term survival,with a tumor growth inhibition rate of 82.3% at 30 days.Of MCA207 sarcoma-bearing mice immunized with mHSP/Ps isolated from MCA207 cells,50% showed tumor regression and long-term survival with a tumor growth inhibition rate of 79.3%.All control mice died within 40 days.The proportions of natural killer cells,CD8＋,and interferon-γ-secreting cells and tumor-specific cytotoxic T-lymphocyte activity were increased in the immunized group.Conclusions：Vaccination with a polyvalent mHSP/P cancer vaccine can induce an immunological response and a marked antitumor response to autologous tumors.This mHSP/P vaccine exerted greater antitumor effects than did HSPT0,HSP60,or tumor lysates alone.

Transition-metal-catalyzed C-H functionalization for late-stage modification of peptides and proteins

Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.

COVID-19,liver dysfunction and pathophysiology:A conceptual discussion

The intra and extracellular pathways of hepatic injury by coronavirus disease 2019(COVID-19)are still being studied.Understanding them is important to treat this viral disease and other liver and biliary tract disorders.Thus,this paper aims to present three hypotheses about liver injury caused by COVID-19:(1)The interactions between severe acute respiratory syndrome coronavirus 2 spike protein and membrane receptors in the hepatocyte;(2)The dysbiosis and"gutliver axis"disruption in patients with serious clinical presentations of COVID-19;and(3)The inflammatory response exacerbated through the production of interleukins such as interleukin-6.However,despite these new perspectives,the pathophysiological process of liver injury caused by COVID-19 is still complex and multifactorial.Thus,understanding all these variables is a challenge to science but also the key to propose individualized and effective patient therapies.

Endogenous modulators in the regulation of ion transporting enzymes: structure, function, interactions, recent advancements and future perspectives

A prerequisite for life is the ability to uphold electro-chemical imbalance across biomembranes. Ion trans- porting enzymes, known as specific pumps, are re-sponsible for the transport of various ions across cell membranes to sustain the same. In all eukaryotes, the plasma membrane potential and secondary transport systems are maintained by the activity of P-type ion transporting enzymes, commonly known as ATPase membrane pumps. Malfunction of pumps leads to various cell disorders and subsequently diseases like cardiac problems, renal malfunctionings, diabetes, cataract, even cancer. Activities/functions of these pumps are regulated either by exogenous agents or by endogenous substances like proteins, peptides, hormones, etc., which are collectively known as mo- dulators. Some of these endogenous modulators may be useful for developing drugs depending on the na-ture of regulation. For more than last two decades, researchers across the globe are exploring the me- chanism of action of different endogenous modulators on these ion transporting enzymes with the aim of developing target-specific drugs. In this review, we have discussed recent advances in our understanding of ATPase pumps, e.g., Ca2+-, Na+, K+-, Ca2+, Mg2+-, H+, K+-ATPases, with the emphasis on their functional regulation by a number of endogenous modulators, and the implications of development of some of these modulators as potential drugs.

Expert systems for HPLC in biochemistry—The knowledge base for selection of HPLC column system in the separation of amino acids, peptides and proteins

The strategy of expert system for high performance liquid chromatography was discussed, the attentions are mainly placed on the knowledge base for selection of column system, separation modes and detection modes in the analysis of amino acids, peptides and proteins.

Antioxidant and free radical-scavenging activities of black soybean peptides (BSP)

The antioxidant and free radical-scavenging activities of black soybean peptides(BSP)fractions(Fra-Ⅰ,Fra-Ⅱ,Fra-Ⅲ)were investigated using reducing power and DPPH·/superoxide/hydroxyl radical-scavenging assay.The reducing power activity of Fra-Ⅲwas closer to that of BHT but lower than that of ascorbic acid.Fra-Ⅲshowed the strongest scavenging activity against free radicals.The radical-scavenging effect was in a dose-dependent manner and the IC50 values for DPPH·,superoxide and hydroxyl radicals were found to be 1.873,1.684 and 1.735 mg/mL,respectively.Amino acid analysis showed that Fra-Ⅲhad high hydrophobic amino acids(HAA)content and hydrophobicity.The molecular weight distribution of Fra-Ⅲwas found to vary from 100 to 1,000 Da mainly.The antioxidant activity of Fra-Ⅲis clearly related to the amino acid composition,the content of HAA and the molecular mass.The present study suggests that BSP with low molecular weight are useful nutritional antioxidant and potential functional factor for anti-aging.

Photoprotective effect of the N-terminal 5-mer peptide analog P165 of amyloid precursor protein in human dermal fibroblasts

Background We showed in our previous study that the N-terminal 17-mer peptide of amyloid precursor protein （APP17-mer peptide）,an active peptide segment with trophic and antioxidative effects,protects skin fibroblasts against ultraviolet （UV） damage and downregulates matrix metalloproteinase 1 （MMP-1） expression.The aim of the current study was to explore the protective effects of P165,the N-terminal 5-mer peptide analog of amyloid precursor protein that is resistant to enzymolysis,on UVA-induced damage in human dermal fibroblasts （HDFs）.Methods HDFs were cultured in Dulbecco＆#39;s modified Eagle＆#39;s medium without and with P165 （concentrations were 1,10,and 100 μJmol/L）.Then,15 J/cm2 UVA irradiation was used to obtain the UV-irradiated model.Cell proliferation was analyzed using MTT kit.The collagen type Ⅰ and MMP-1 contents in cell lysate were determined by enzyme-linked immunosorbent assay （ELISA）.Fluorometric assays were performed to detect the formation of intracellular reactive oxygen species （ROS） in the cells.Results P165 significantly protected the HDFs against UVA-induced cytotoxicity.Compared with the UVA-irradiated control,1,10,and 100 μmol/L P165 elevated cell proliferation by 14.98% （P〈0.05）,17.52% （P〈0.01） and 28.34% （P〈0.001）,respectively.Simultaneously,10 and 100 μmol/L P165 increased collagen type Ⅰ content （both P〈0.05）.Moreover,P165 treatment （all concentrations） also markedly suppressed the UVA-induced MMP-1 expression （all P〈0.001）.P165 at 1,10,and 100 μmol/L also reduced UVA-induced ROS generation by 11.27%,13.69% （both P〈0.05）,and 25.48% （P〈0.001）,respectively.Conclusions P165 could protect the HDFs against UVA-induced photodamage,including cytotoxicity,and MMP-1 generation.Furthermore,it also increased the collagen type Ⅰ content in the cells.The inhibitory effect on intracellular ROS generation might be involved in these photoprotective effects.Thus,P165 may be a useful candidate in the prevention and treatment of skin photoaging.

Emerging prospects of protein/peptide-based nanoassemblies for drug delivery and vaccine development

Proteins have been widely used in the biomedical field because of their well-defined architecture,accurate molecular weight,excellent biocompatibility and biodegradability,and easy-to-functionalization.Inspired by the wisdom of nature,increasing proteins/peptides that possess self-assembling capabilities have been explored and designed to generate nanoassemblies with unique structure and function,including spatially organized conformation,passive and active targeting,stimuli-responsiveness,and high stability.These characteristics make protein/peptide-based nanoassembly an ideal platform for drug delivery and vaccine development.In this review,we focus on recent advances in subsistent protein/peptide-based nanoassemblies,including protein nanocages,virus-like particles,self-assemblable natural proteins,and self-assemblable artificial peptides.The origin and characteristics of various protein/peptide-based assemblies and their applications in drug delivery and vaccine development are summarized.In the end,the prospects and challenges are discussed for the further development of protein/peptide-based nanoassemblies.

Immunity of the greater wax moth Galleria mellonella

Investigation of insect immune mechanisms provides important information concerning innate immunity, which in many aspects is conserved in animals. This is one of the reasons why insects serve as model organisms to study virulence mechanisms of human pathogens. From the evolutionary point of view, we also learn a lot about host-pathogen interaction and adaptation of organisms to conditions of life. Additionally, insect-derived antibacterial and antifungal peptides and proteins are considered for their potential to be applied as alternatives to antibiotics. While Drosophila melanogaster is used to study the genetic aspect of insect immunity, Galleria mellonella serves as a good model for biochemical research. Given the size of the insect, it is possible to obtain easily hemolymph and other tissues as a source of many immune-relevant polypeptides. This review article summarizes our knowledge concerning G. mellonella immunity. The best-characterized immune-related proteins and peptides are recalled and their short characteristic is given. Some other proteins identified at the mRNA level are also mentioned. The infectious routes used by Galleria natural pathogens such as Bacillus thuringiensis and Beauveria bassiana are also described in the context of host-pathogen interaction. Finally, the plasticity of G. mellonella immune response influenced by abiotic and biotic factors is described.

Fabrication of subunit nanovaccines by physical interaction

Vaccines can improve the quality of human life by preventing the burden of infectious diseases.Also,vaccination is becoming a powerful medication for preventing and treating tumors.Various vaccines have been developed based on the origin of the antigens.Herein,we focus on the subunit vaccines whose antigens are proteins or peptides.The advantage of subunit vaccines is safety for recipients;however,the immunogenicity of subunit antigens is relatively low.Nanoparticular delivery systems have been applied to improve the immunocompetence of subunit vaccines by targeting lymph nodes,and effectively present antigens to immune cells.Moreover,adding appropriate molecular adjuvants may strengthen the antigens to elicit immune response.In this perspective article,we first elucidate the characteristics of immunity induced by subunit nanovaccines and then summarize the strategies to fabricate subunit nanovaccines with delivering materials.Herein we highlight non-covalent interaction to fabricate nanoparticular subunit vaccines.

Sequence Pattern Correlation of Amino Acid in Collision-induced Dissociation Electrospray Ionization Mass Spectrometry

A novel approach of sequence pattern correlation has been applied to predict an expected amino acid sequence from CID ESI MS spectra. The proposed approach deduces sequence patterns with no help from known protein database such that it is useful to identify an unknown peptide or new protein. The algorithm applies a cross correlation to match an experimental CID spectrum with predicted sequence pattern generated from fragmentation information. The fragmentation knowledge of both y series and other non y series are utilized to generate the predicted sequence patterns. In contrast to the normal de novo approach, the proposed approach is insensitive to mass tolerance and non susceptive to spectral integrality with no need for selection of a starting point.