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Biomaterial matrices must permit tissue growth and maturation for the success of tissue regeneration strategies. Naturally, this accommodation is achieved via the dynamic remodeling of a cell's extracellular matrix (ECM). Synthetically, hydrolytic or enzymatic degradation are often engineered into materials for this purpose. More recently, supramolecular interactions have been used to provide a biomimetic and tunable mechanism to facilitate tissue formation via their dynamic and reversible non-covalent interactions. By engineering the mechanical and bioactive properties of a material, supramolecular chemists are able to design permissivity into the construct and facilitate tissue integration in-vivo . Furthermore, via the reversibility of non-covalent interactions, injectability and responsiveness can be designed for enhanced delivery and spatio-temporal control. In this review, we delineate the basic considerations needed when designing permissive supramolecular hydrogels for tissue engineering with an eye toward tissue growth and integration. We highlight three archetypal hydrogel systems that have shown well-documented tissue integration in vivo, and provide avenues to assess tissue in-growth. Careful design and assessment of the biomedical potential of a supramolecular hydrogels can inspire the creation of robust and dynamic implants for new tissue engineering applications. Statement of significance Tissue engineering and regeneration require careful design of materials to coax the tissue formation process. The materials must provide the cells with a proper environment, but also get out of the way to allow new tissue to form. Normally, biomaterial hydrogels are designed to chemically degrade to permit tissue formation; however, dynamic and reversible supramolecular interactions can be used to facilitate tissue formation and remodelability. Herein we review the common design parameters for supramolecular hydrogels and highlight applications where they have shown the ability to facilitate tissue formation via their dynamic interactions. The review also briefly provides insight into the functionality and control enabled by supramolecular design and the methods one can use to start to assess cell migration and tissue integration. (c) 2021 Published by Elsevier Ltd on behalf of Acta Materialia Inc.

Mulberry leaves are rich in 1-deoxynojirimycin (DNJ) and 2-O-α-D-galactopyranosyl-deoxynojirimycin (GAL-DNJ). Compared to DNJ, the bioactive potency of GAL-DNJ is low. We proposed that the conversion of GAL-DNJ into DNJ may improve its bioavailability. We evaluated this hypothesis and constructed a novel enzymatic-based method to induce the hydrolysis of GAL-DNJ to DNJ in order to improve the therapeutic potency of mulberry leaves.

International audience; Noctoc commune is a cyanobacterium living in various and extreme environments. Its ability to survive in desert, on ice or high altitude is explained by its exceptional metabolism and its capacity to resist to desiccation. N. commune cells are embedded in a gelatinous matrix made of polysaccharides which fixes water and participates in maintaining the cells in hydrated conditions. The structure of the polysaccharide of N. commune harvested in Saint Martin d'Uriage (France) and the oligosaccharides obtained after its enzymatic degradation were determined. The repeating unit of the main chain is a tetra-saccharide: [→4)-β-D-Glcp-(1 → 4)-β-D-Xylp-(1 → 4)-β-D-Glcp-(1 → 4)-α-D-Galp-(1→], branched at position 6 of a glucose residue by a β-linked pyruvated glucuronic acid residue. About 30% of the Xylp residues were branched with a Xylf residue. Comparison of this structure with the polysaccharides secreted by other Nostoc species and strains suggest a strong selection pressure on the structure in agreement with its important biological role.

International audience; Heteroxylans (HX) from vitreous and floury parts of maize endosperm were isolated. Structural analysis showed a xylan backbone with few unsubstituted xylose residues (

Fructans are carbohydrates present in more than 15% of flowering plants. They represent the major pool of carbohydrates in some species, especially when facing cold or drought. However, the functions of fructans with high or low degrees of polymerization (DP), their diurnal use, and the regulation of their synthesis and degradation in response to stresses still remain unclear. Here we present an enzymatic protocol adapted to 96-well microplates that simultaneously allows the determination of fructans and glucose, fructose, and sucrose. Moreover, the protocol allows to estimate the average DP of the fructans in the samples. The protocol is based on the enzymatic degradation of fructans into glucose and fructose and their subsequent conversion into gluconate 6-phosphate concomitant with the formation of NADH in the presence of ATP.

Filamentous fungi as a source of bioproteins for biotechnological applications are preferred over bacteria and yeasts due to their excellent yield and total volume of production. Fungal laccases are useful because of high redox potentials and low substrate specificity to xenobiotics. However, challenges for large-scale utilizations are low enzyme yield and high cost of production. Saw-dust of Terminalia superba abounds locally and was utilized as alternative substrate for production using various optimization processes. Trametes sp. isolate B7 was isolated and identified using molecular techniques. Optimum pH and temperature for total soluble protein (TSP) and laccase activity were pH 5.0 (3.6 mg/mL, 2356 U/mL) and 25oC (2.3 mg/mL, 2395 U/mL), respectively. Enhanced production of TSA occurred in Cu2+ (2.70 mg/L) and Ca2+ (2.50 mg/L) at 3 mM. Laccase activity was recorded at 1 - 2 mM Cu2+ (2379 U/mL) and 3 - 4 mM Ca2+ (2385 U/mL). Productions of TSP and laccase activity were higher using ammonium sulphate and ammonium chloride respectively. Glucose induced the best TSP and laccase activity of 3.6 mg/mL and 2395 U/mL respectively. TSP and laccase activity were best on day 14 (3.6 mg/mL) and day 18 (2395 U/mL) respectively. Percentage degradation of synthetic dyes using crude laccase 1000 U/mL (and 2000 U/mL) were: Remazol Brilliant Blue Royal 100% (77%), Phenol red 28% (36%), Congo red 75% (64%), and Malachite green 62% (28%) respectively. The ability of laccase to degrade Phenol red and other synthetic dyes without using enzyme mediators made it a valuable tool for biotechnological applications.

Enzymatic hydrolysis of polyethylene terephthalate (PET) has been the subject of extensive previous research that can be grouped into two categories, viz. enzymatic surface modification of polyester fibers and management of PET waste by enzymatic hydrolysis. Different enzymes with rather specific properties are required for these two processes. Enzymatic surface modification is possible with several hydrolases, such as lipases, carboxylesterases, cutinases, and proteases. These enzymes should be designated as PET surface–modifying enzymes and should not degrade the building blocks of PET but should hydrolyze the surface polymer chain so that the intensity of PET is not weakened. Conversely, management of PET waste requires substantial degradation of the building blocks of PET; therefore, only a limited number of cutinases have been recognized as PET hydrolases since the first PET hydrolase was discovered by Müller et al. (Macromol Rapid Commun 26:1400–1405, 2005). Here, we introduce current knowledge on enzymatic degradation of PET with a focus on the key class of enzymes, PET hydrolases, pertaining to the definition of enzymatic requirements for PET hydrolysis, structural analyses of PET hydrolases, and the reaction mechanisms. This review gives a deep insight into the structural basis and dynamics of PET hydrolases based on the recent progress in X-ray crystallography. Based on the knowledge accumulated to date, we discuss the potential for PET hydrolysis applications, such as in designing waste stream management. Electronic supplementary material The online version of this article (10.1007/s00253-019-09717-y) contains supplementary material, which is available to authorized users.

Arginine (Arg)-rich cell-penetrating peptides (CPPs) are promising tools for plasmid DNA (pDNA) delivery. α-Aminoisobutyric acid (Aib) is known to stabilize peptide helical secondary structures and has been used as a building block for foldamers. In the current study, we prepared Aib CPP foldamers, (Arg–Arg–Aib)n (n = 1–6) and examined their pDNA transfection abilities. Transfection efficiencies of peptide/pDNA complexes are dependent on peptide chain length, with longer peptides (n ≥ 4) exhibiting better transfection abilities than an Arg nonapeptide. Furthermore, Aib CPP foldamers achieve prolonged transfection abilities compared with commercially available transfection reagents, which is probably because of the high resistance of the peptides to enzymatic degradation, thereby protecting the encapsulated pDNA for a long period. The obtained results demonstrated promising features of Aib CPP foldamers as pDNA delivery carriers.

White-rot fungus Rigidoporus sp. FMD21 is a lignin-modifying enzyme producing fungus that can degrade dioxin. Extracellular enzymes from FMD21 include laccase and manganese peroxidase which are promising enzymes for myco-remediation because of their wide substrate specificity and mild catalysis conditions. The FMD21 genome was sequenced using Ion Torrent technology and consists of 38.98 Mbps with a GC content of 47.4 %. Gene prediction using Augustus with Basidiomycota reference setting resulted in 8245 genes. Functional gene annotations were carried out by using several programs and databases. We focused on laccase and ligninolytic peroxidase genes, which are most likely involved in the degradation of aromatic pollutants. The genome of FMD21 contains 12 predicted laccase genes (10 out of 12 predicted as full length) and 13 putative ligninolytic peroxidases which were annotated as MnP or versatile peroxidases. Four predicted laccases showed a higher than 65 % binding chance to 2,3,7,8-TCDD with the highest at 72 % in in silico docking analysis. Heterologous expressed laccases showed activity towards three tested substrates included ABTS, guaiacol and 2,6-DMP. ABTS displayed two-stage oxidation which differed from natural FMD21 laccases. 2,3,7,8-TCDD was degraded by 50 % after two weeks of enzymatic treatment by three out of five laccase isozymes which were natural laccases secreted by FMD21. In this study, we provide direct evidence for the 2,3,7,8-TCDD biodegradation capability of fungal laccases.

Plastic waste poses an enormous environmental problem as a result of soil and ocean contamination, causing the release of microplastics that end up in humans through the food web. Enzymatic degradation of plastics has emerged as an alternative to traditional recycling processes. In the present work, we used bioinfomatics tools to discover a gene coding for a putative polyester degrading enzyme (polyesterase). The gene was heterologously expressed, purified and biochemically characterized. Furthermore, its ability to degrade polyethylene terephthalate (PET) model substrates and synthetic plastics was assessed.

International audience; Bacteriocins are antimicrobial peptides some of which are endowed with antiviral, anticancer and antibiofilm properties. These properties could be improved through synergistic interactions of these bacteriocins with other bioactive molecules such as antibiotics, phages, nanoparticles and essential oils. A number of studies are steadily reporting the effects of these combinations as new and potential therapeutic strategies in the future, as they may offer many incentives over existing therapies. In particular, bacteriocins can benefit from combination with nanoparticles which can improve their stability and solubility, and protect them from enzymatic degradation, reduce their interactions with other molecules and improve their bioavailability. Furthermore, the combination of bacteriocins with other antimicrobials is foreseen as a way to reduce the development of antibiotic resistance due to the involvement of several modes of action. Another relevant advantage of these synergistic combinations is that it decreases the concentration of each antimicrobial component, thereby reducing their side effects such as their toxicity. In addition, combination can extend the utility of bacteriocins as antiviral or anticancer agents. Thus, in this review, we report and discuss the synergistic effects of bacteriocin combinations as medicines, and also for other diverse applications including, antiviral, antispoilage, anticancer and antibiofilms.

Most proteins in cell and tissue lysates are soluble. We show here that in lysate from human neurons, more than 1,300 proteins are maintained in a soluble and functional state by association with endogenous RNA, as degradation of RNA invariably leads to protein aggregation. The majority of these proteins lack conventional RNA‐binding domains. Using synthetic oligonucleotides, we identify the importance of nucleic acid structure, with single‐stranded pyrimidine‐rich bulges or loops surrounded by double‐stranded regions being particularly efficient in the maintenance of protein solubility. These experiments also identify an apparent one‐to‐one protein‐nucleic acid stoichiometry. Furthermore, we show that protein aggregates isolated from brain tissue from Amyotrophic Lateral Sclerosis patients can be rendered soluble after refolding by both RNA and synthetic oligonucleotides. Together, these findings open new avenues for understanding the mechanism behind protein aggregation and shed light on how certain proteins remain soluble., This study shows that RNA plays an important and direct role in maintaining protein solubility and preventing protein aggregation.

Cyclotides are plant-derived mini-proteins of 28 - 37 amino acids. They have a characteristic head-to-tail cyclic backbone and three disulfide cross-linkages formed by six highly conserved cysteine residues, creating a unique knotted ring structure, known as a cyclic cystine knot (CCK) motif. The CCK topology confers immense stability to cyclotides with resistance to thermal and enzymatic degradation. Native cyclotides are of interest due to their multiple biological activities with several potential applications in agricultural (e.g. biopesticides, antifungal) and pharmaceutical (e.g. anti-HIV, cytotoxic to tumor cells) sectors. The most recent application of insecticidal activity of cyclotides is the commercially available biopesticidal spray known as 'Sero X' for cotton crops. Cyclotides have a general mode of action and their potency of bioactivity is determined through their binding ability, pore formation and disruption of the target biological membranes. Keeping in view the important potential applications of biological activities of cyclotides and the lack of an extensive and analytical compilation of bioactive cyclotides, the present review systematically describes eight major biological activities of the native cyclotides from four angiosperm families viz. Fabaceae, Poaceae, Rubiaceae, Violaceae. The bioactivities of 94 cytotoxic, 57 antibacterial, 44 hemolytic, 25 antifungal, 21 anti-HIV, 20 nematocidal, 10 insecticidal and 5 molluscicidal cyclotides have been comprehensively elaborated. Further, their distribution in angiosperm families, mode of action and future prospects have also been discussed.

Important elements for an efficient tumor targeted delivery are cancer-specific de novo- or over-expression of target receptors and their availability on the tumor cell surface. Peptides can be designed to selectively bind to such receptors and act as tumor-targeting ligands, as has been revealed in several preclinical studies. Notably, the amino acid sequences of these peptides can be chemically modified to prevent enzymatic degradation and improve the stability of the peptide. Furthermore, tumor-targeting peptides can be conjugated to the surface of nanosized drug carriers for the selective delivery of anticancer drugs to tumors. In this review, tumor receptors for which targeting peptides have been identified are described, and their targeting potential is considered. Various chemical modifications of peptides are thoroughly described, and targeting peptides as well as peptide-functionalized nanocarriers are critically discussed. The limitations of active targeting nanocarriers are evaluated in detail, and an outlook on the potential of tumor-targeting peptides and their clinical applications is provided.

Carbon nanomaterials (CNMs) with unique physicochemical properties are widely applied in various fields, thus inevitably being released into the environment and posing threat to organisms and human beings. Simultaneously, CNMs in the environment could be degraded under natural conditions, and the toxicity of CNMs to organisms will be altered because of the changes in the structural and surface properties of CNMs. Therefore, a systematical summarization on the environmental degradation of CNMs is in urgent need. In this review, degradation routes of CNMs were addressed by dividing into biodegradation and abiotic degradation. Biodegradation included enzymatic degradation, microbial degradation, and cell degradation, while abiotic degradation included photodegradation and chemical (photochemical) degradation. All the above degradation routes were elaborated in the present review. The degradation of CNMs in different natural conditions was thoroughly summarized, and the degradation mechanisms were also concluded. In addition, current challenges on the investigations of CNMs degradation were prospected. The review could provide important information for better understanding the environmental fates and biological effects of CNMs.

Cow's milk is one of the most common allergenic foods. Cow's milk allergy is mainly an IgE-mediated hypersensitivity reaction, and the major allergens from cow's milk have been found to be caseins, β-lactoglobulin, and α-lactalbumin. Several peptides derived from bovine casein are known allergens in cow's milk. To reduce their allergenicity, these proteins can be degraded by food-grade peptidases. We succeeded in detection of two peptides, VLPVPQK and FFVAPFPEVFGK, from bovine casein-derived allergen peptides by using an ion trap LC-MS apparatus. This study focuses on the synergistic effects of Streptomyces aminopeptidases belonging to the M1, M24, and M28 families on the degradation of the allergen peptides. From these results, we demonstrated that the combination of M1 and M24 aminopeptidases was the most effective for degrading the abovementioned allergenic peptides.

The potential of macrocyclic peptides as therapeutics has garnered much attention over the last several years. Unlike their linear counterparts, macrocycles have higher resistance to enzymatic degradation and often display improved bioavailability. However, macrocycles are typically not lipophilic enough for cellular membrane penetration, which prevents them from interacting with intracellular targets. Methods to increase cellular permeability have involved the incorporation of bicyclic scaffolds, d-amino acids and N-methylation of amides. These modifications exert their effect through conformational control of macrocycles and have been well studied in the literature. In contrast, the structural consequences of heterocycle incorporation into macrocyclic rings has not been as exhaustively investigated. In this mini-review we discuss key examples in which heterocycles influence the conformational stability and other properties of macrocycles.

Studying the enzymatic degradation of synthetic polymers is crucial for the design of suitable materials for biomedical applications ranging from advanced drug delivery systems to tissue engineering. One of the key parameters that governs enzymatic activity is the limited accessibility of the enzyme to its substrates that may be collapsed inside hydrophobic domains. PEG-dendron amphiphiles can serve as powerful tools for the study of enzymatic hydrolysis of polymeric amphiphiles due to the monodispersity and symmetry of the hydrophobic dendritic block, which significantly simplifies kinetic analyses. Using these hybrids, we demonstrate how precise, minor changes in the hydrophobic block are manifested into tremendous changes in the stability of the assembled micelles toward enzymatic degradation. The obtained results emphasize the extreme sensitivity of self-assembly and its great importance in regulating the accessibility of enzymes to their substrates. Furthermore, the demonstration that the structural differences between readily degradable and undegradable micelles are rather minor, points to the critical roles that self-assembly and polydispersity play in designing biodegradable materials.

Chondroitin sulfate (CS) is a structurally complex polyanionic glycosaminoglycan that plays essential roles in physiological processes. Here we report a facile approach to a library of CS tetra- and hexasaccharides based on the enzymatic degradation of chondroitin over 10 or 11 steps, which is the shortest synthetic route toward size-defined CS oligosaccharides reported to date. Subsequent biotinylation enabled the investigation of their interactions with growth factors, filling in the gaps of the existing research, and providing probes for further exploration of the biological functions of CS.

Indoleamine 2,3-dioxygenase (IDO) is an immunomodulating enzyme that is overexpressed in many cancers with poor prognosis. IDO suppresses T cell immunity by catabolizing tryptophan into kynurenine (KYN), which induces apoptosis in T effector cells and enhances T regulatory cells, providing a powerful immunosuppressive mechanism in tumors. Thus, major efforts for developing IDO inhibitors have been undertaken. Among them, 1-Methyl-l-Tryptophan (MLT) and 1-Methyl-d-Tryptophan (MDT) effectively inhibit IDO in preclinical tumor models and the latter is under clinical evaluation. However, both MLT and MDT present poor pharmacokinetics, with the maximum serum concentration being below their 50% inhibitory concentration value. Herein, we have developed polymeric IDO inhibitors based on MLT, which can release active MLT after enzymatic degradation, toward establishing superior antitumor immunotherapies. These polymers were prepared by ring opening polymerization of an N-phenyl carbamate (NPC) derivative of MLT that was synthesized by carbamylation with diphenyl carbonate. By using &omega, amino-poly(ethylene glycol) (PEG-NH2) as the macroinitiator, we prepared amphiphilic PEG-poly(MLT) block copolymers, which self-assembled into polymeric micelles in aqueous conditions. The PEG-poly(MLT) block copolymers could be readily degraded by chymotrypsin and the micelles were able to reduce the levels of KYN in activated macrophages. These results provide a strong rationale for pursuing MLT-based polymeric micelles as tumor-targeted prodrug systems.

Enzymatic degradation of locust bean gum provides a Manβ(1 → 4)Man disaccharide, which may be converted into the core Manβ(1 → 4)GlcNAc disaccharide unit of all N-glycans via conversion to a 2-iodo-glycosyl azide, and Lafont rearrangement. The Manβ(1 → 4)GlcNAc disaccharide may be used as a key intermediate for elaboration into more complex N-glycan structures providing a route to N-glycan oxazolines as donor substrates for ENGase enzymes that is considerably shorter than those reported previously.

Thymidine derivatives bearing spiroacetal moieties on the C4'-position (5'R-spiro-thymidine and 5'S-spiro-thymidine) were synthesized and incorporated into oligonucleotides. The duplex- and triplex-forming abilities of both the oligonucleotides were evaluated from UV melting experiments. Oligonucleotides with the 5'S-spiro modifications could form thermally stable duplexes with complementary RNA and DNA; however, the 5'R-spiro modification significantly decreased the thermal stabilities of the duplexes and triplexes. Oligonucleotides with these spiro-thymidines showed significantly high resistance towards enzymatic degradation.

Lignocelluloses contained in animal forage cannot be digested by pigs or poultry with 100% efficiency. On contrary, Aspergillus fumigatus, a saprophytic filamentous fungus, is known to harbor 263 glycoside hydrolase encoding genes, suggesting that A. fumigatus is an efficient lignocellulose degrader. Hence the present study uses corn, wheat, or soybean as a sole carbon source to culture A. fumigatus under animal physiological condition to understand how cellulolytic enzymes work together to achieve an efficient degradation of lignocellulose. Our results showed that A. fumigatus produced different sets of enzymes to degrade lignocelluloses derived from corn, wheat, or soybean cell wall. In addition, the cellulolytic enzymes produced by A. fumigatus were stable under acidic condition or at higher temperatures. Using isobaric tags for a relative and absolute quantification (iTRAQ) approach, a total of ∼600 extracellular proteins were identified and quantified, in which ∼50 proteins were involved in lignocellulolysis, including cellulases, hemicellulases, lignin-degrading enzymes, and some hypothetical proteins. Data are available via ProteomeXchange with identifier PXD004670. On the basis of quantitative iTRAQ results, 14 genes were selected for further confirmation by RT-PCR. Taken together, our results indicated that the expression and regulation of lignocellulolytic proteins in the secretome of A. fumigatus were dependent on both nature and complexity of cellulose, thus suggesting that a different enzyme system is required for degradation of different lignocelluloses derived from plant cells. Although A. fumigatus is a pathogenic fungus and cannot be directly used as an enzyme source, as an efficient lignocellulose degrader its strategy to synergistically degrade various lignocelluloses with different enzymes can be used to design enzyme combination for optimal digestion and absorption of corn, wheat, or soybean that are used as forage of pig and poultry.

Microbial adhesion is an essential step in infection and is mediated primarily by protein-carbohydrate interactions. Antagonists of such interactions have become a promising target for anti-adhesive therapy in several infective diseases. Monovalent protein-sugar interactions are often weak, and most successful anti-adhesive materials consist of multivalent glycoconjugates. Although often very effective in hampering microbial adhesion, natural epitopes often show limited resistance to enzymatic degradation. The use of carbohydrate mimics (glycomimetics) as a replacement for natural sugars potentially allows higher metabolic stability and also higher selectivity towards the desired protein target. In this review we describe the state of the art in the design and synthesis of glycoconjugates and glycomimetics employed for the construction of anti-adhesive biomaterials.

Hyaluronic acid (HA) is the most common component of aesthetic fillers. Many formulations exist, each exhibiting properties that are manifestations of individual molecular modifications. The enzyme hyaluronidase degrades hyaluronic acid and can therefore be injected into soft tissue to reduce suboptimally placed HA fillers or to reverse local ischemic complications. The clinically available varieties of hyaluronidase may be derived from crude animal extracts or genetically engineered from recombinant human DNA. Different HA fillers are not uniformly dissolved by a single source hyaluronidase, and hyaluronidase from different sources may have varying efficacy in the degradation of HA. Previous studies of subsets of HA fillers and hyaluronidases have provided limited and often conflicting data regarding these differences, and a more comprehensive scientific study is needed. In this review, the authors describe commonly available formulations of HA and hyaluronidase and review all studies of HA-hyaluronidase interaction available via a PubMed and Google Scholar search from 2005 to present, exploring trends in the data. Factors determined to confer increased resistance to degradation included higher concentration of HA, higher crosslinking density, and status as monophasic versus biphasic. Fillers of the Juvéderm family were generally found to be more resistant to degradation than members of the Restylane family. Results are less consistent for Belotero Balance. No variety of hyaluronidase was consistently superior at dissolving any variety of HA filler. More research is needed to clarify these clinically relevant relationships.

Low molecular weight heparin (LMWH) possesses a dual function of anticoagulation and anti-inflammation. While the structures and mechanisms on its anticoagulation have been widely studied, the structural features responsible for the anti-inflammatory activity of LMWH remain to be explored. In the present study, guided by an anti-inflammation assay, a non-anticoagulant species was generated from partial desulfation of LMWH to fully retain the anti-inflammatory activity, from which five fractions were further separated and three of them were characterized by enzymatic degradation, hydrophobic labeling, C18-based HPLC and LC-MS/MS analyses. The structure-activity relationship revealed that the sulfate groups in LMWH are critical to distinguish and separate the activities of anticoagulation and anti-inflammation, leading to the identification of a synthetic heparosan-type heptasaccharide as a potent anti-inflammatory agent. The present strategy enables the simplification of complex polysaccharides to bioactive synthetic oligosaccharides for therapeutic utility.

Partial enzymatic degradation of human serum albumin in vivo can lead to the generation of peptides with novel functions or to peptides that might serve as biomarkers for disease. In pathological conditions, biomarkers are possibly produced from the protein in the lysosomes and set free by cell death, or cell death could release acid endoproteases which produce biomarkers by degrading extracellular albumin. Alternatively, lysosomes or secretory granules can be stimulated to release enzymes which produce bioactive peptides from albumin. In physiological conditions, it is proposed that bioactive peptides can be made by enzymatic attack on the protein bound to the endosomal neonatal Fc receptor. The peptides formed could leave the cell, together with native albumin, by exocytosis. Thus, the receptor could have a new function in addition to saving albumin from degradation in the lysosomes. Large amounts of albumin are degraded every day, and this fact can compensate for the short in vivo half-lives of the bioactive peptides. One or more of the procedures outlined above could also apply to other plasma proteins or to structural proteins.

In the present study, culture conditions of Streptococcus equi was optimized through Box–Behnken experimental design for hyaluronic acid production. About 0.87 gL−1 of hyaluronic acid was p...

Efficient degradation of complex lignocellulosic materials requires the synergistic action of different types of enzymes. Characterizing the compositions of lignocellulolytic enzyme mixtures could provide comprehensive understandings about the enzymatic degradation of lignocelluloses. In this chapter, we present a proteomic strategy for the analysis of enzyme mixtures produced by lignocellulolytic fungi. The described method is easy to carry out and is suitable to determine the composition of lignocellulolytic enzyme mixtures in a semiquantitative manner. Comparison of the compositions of enzyme mixtures with different degrading efficiencies allows for the identification of candidate targets for the optimization of lignocellulolytic enzyme mixtures.

Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry has become an indispensable tool for bacterial and fungal identification in clinical laboratories. Progress has been significant in the identification of resistance mechanisms by MALDI-TOF mass spectrometry based on the enzymatic degradation of antimicrobial agents, more specifically, in the detection of β-lactamases, especially carbapenemases. However, this technology has some limitations and new protocols should be developed and validated for application in clinical laboratories. Methods based on the different protein fingerprint of resistant microorganisms as compared to susceptible microorganisms of the same species are a promising avenue of research. The same applies to the MALDI-TOF–based rapid resistance detection by stable isotope labeling. MALDI-TOF mass spectrometry can cause a revolution in the field of microbiological diagnosis in the detection of serum biomarkers of infectious diseases, toxins, or specific microbial antigens.

We used a previously developed simulation model of a plant cell wall and its enzymatic degradation to compare the abilities of two hemicelluloses, glucuronoarabinoxylan (GAX) and xyloglucan (XG), to protect cellulose microfibrils (CMFs) from attack by cellulose-degrading enzymes. Additionally, we investigated the effect of XG abundance on the degradation rate of CMFs in the presence of the same enzymes. Simulations were run using hypothetical cell-wall compositions in which the numbers and arrangement of CMFs and (1,3, 1,4)-β-glucan were kept constant, but the proportions of GAX and XG were altered. Scenarios considered walls with low and equal proportions of either GAX or XG, and also low, medium and high proportions of XG in the absence of GAX. The rate of CMF degradation was much lower in walls with GAX than walls with XG, except for early in the simulation when the reverse held, suggesting that XGs were protecting CMFs by competitive inhibition. Increasing XG content reduced both the degradation rate of CMFs and the percent of XG degraded, indicating that activity of enzymes decreased with XG density despite XG being degradable. Glucose oligosaccharide breakdown products were analysed on the basis of the originating polysaccharide and their degree of polymerisation (DP). The presence of GAX as opposed to equal amounts of XG had some significant effects on the amount and profile of breakdown products from XG and CMFs.

Biodegradable polymer composites based on poly(ɛ-caprolactone) (PCL) and poly(lactic acid) (PLA) fibers with diameters of 18, 26, 180 μm were prepared by melt compounding. The PLA fiber content in the composites was constant at 20% by weight. The effects of fibers with different diameters on the physical properties and enzymatic degradation of PCL were investigated. The morphological analysis indicated good interfacial adhesion between PCL and PLA fiber, which was beneficial to improve the physical properties of PCL. With increasing PLA fiber diameter, the complex viscosity and modulus of PCL were significantly increased, especially at low frequencies, indicating that the hindered effect of the fiber on the mobility of the PCL molecular chains was more obvious when PLA fiber diameter was thicker. However, as for the mechanical properties, the reinforcement was more obvious to PCL with the smaller PLA fiber diameter. This was because increasing efficient load transfer may be appeared due to the larger surface area and better interface bonding force of the fiber with thinner diameters. The enzymatic degradation of PCL was accelerated with the addition of large PLA fiber diameter of 26 and 180 μm, and hardly changed with the small PLA fiber diameter of 18 μm.

DNA nanomachines are becoming useful tools for molecular recognition, imaging, and diagnostics and have drawn gradual attention. Unfortunately, the present application of most DNA nanomachines is limited in vitro, so expanding their application in organism has become a primary focus. Hence, a novel DNA nanomachine named t-switch, based on the DNA duplex-triplex transition, is developed for monitoring the intracellular pH gradient. Our strategy is based on the DNA triplex structure containing C(+)-G-C triplets and pH-dependent Förster resonance energy transfer (FRET). Our results indicate that the t-switch is an efficient reporter of pH from pH 5.3 to 6.0 with a fast response of a few seconds. Also the uptake of the t-switch is speedy. In order to protect the t-switch from enzymatic degradation, PEI is used for modification of our DNA nanomachine. At the same time, the dynamic range could be extended to pH 4.6-7.8. The successful application of this pH-depended DNA nanomachine and motoring spatiotemporal pH changes associated with endocytosis is strong evidence of the possibility of self-assembly DNA nanomachine for imaging, targeted therapies, and controllable drug delivery.

Oats is valuable raw material, but it needs to be heat-treated to inactivate lipid degrading enzymes that would deteriorate its sensory quality. The aim was to study if extrusion could replace traditional heat treatment in production of whole meal oats with stable lipids. Flours from non-heat-treated (NHT) oat grains were extruded under four conditions and subjected to 15-week storage. Stability of the extrudates as well as the NHT and heat-treated oat grains were studied for hydrolytic and oxidative reactions by measuring neutral lipid profiles and volatile products. In the NHT oat grains, lipid hydrolysis started immediately after milling, which also promoted lipid oxidation during storage. Enzymatic degradation of lipids could effectively be prevented by extrusion even at the lowest temperature of 70 °C. The extrusion temperature could be increased to 110 °C without subjecting the lipids to non-enzymatic oxidation. However, by increasing the temperature to 130 °C, lipid oxidation was promoted, which also resulted in losses of neutral lipids over time. Hexanoic acid became the major volatile product in oat extrudates during extensive lipid oxidation instead of hexanal, which is a commonly used lipid oxidation indicator. In conclusion, lipids in oat grains could be stabilized by extrusion even at a temperature of 70 °C.

2'-O-AECM modified oligonucleotides provide an unusual combination of remarkable properties. This includes the combination of high resistance towards enzymatic degradation and the spontaneous cellular uptake of AECM oligonucleotides.

Versatile spider silk proteins have been prepared by various methods in morphology of spheres for functional applications. Inspired from natural spinning process, a facile approach for the fabrication of silk spheres is described. Distinct from the traditional emulsification method, silk spheres were assembled as rapidly as 10 s by using the HFIP-on-Oil method without any surfactants and agitation used. Notably, a series of factors, such as evaporation rate of HFIP, polarity and molecular weight of oils play central roles on the final silk morphologies. With regard to the increase of protein concentrations, the average dimension and size distribution of silk spheres were both increased. Together with present study, silk spheres prepared by other methods were summarized for comparison in drug delivery applications. As a proof-of-concept, silk spheres loaded with Rhodamine B and Doxorubicin were investigated for the potential proteinase-enhanced drug delivery. On the extracellular environment, ethanol-mediated silk spheres exhibited higher resistance against enzymatic degradation of proteinase K when compared with pristine spheres. Under fluorescent detection by the aid of CLSM, proteinase-enhanced release behaviors were further demonstrated through in-vitro experiments within Hela cells. The facile fabrication of spheres with tunable β-sheets establishes a fascinating platform for functional silk-based applications.