Purification, crystal structural characterization of porcine kidney dipeptidyl peptidase IV (PkDPP-IV) and its interaction with oyster derived inhibitory peptide ILAPPER.

Dipeptidyl peptidase IV (DPP-IV) is an important target enzyme for the treatment of type 2 diabetes mellitus (T2DM). Increasing researchers try to screen DPP-IV inhibitory peptides while the cost of DPP-IV is high. In this study, PkDPP-IV was efficiently purified by acid precipitation, ammonium sulfate salting out and gel filtration chromatography with a purification of 283.

Collaborative Effect of Matrix Metalloproteinases on Type I Collagen Degradation and Muscle Softening in Sea Bass () during Cold Storage.

Matrix metalloproteinases (MMPs) play critical roles in the degradation of collagens, while their mechanism remains unclear. In the present study, the involvement of matrix metalloproteinases (MMPs) in collagen degradation of sea bass muscle during cold storage was explored. Immunohistochemical staining results showed significant degradation of type I collagen in the connective tissue of muscle endomysium during cold storage, thus affecting the muscle structural integrity and quality.

Stabilization of dimeric PYR/PYL/RCAR family members relieves abscisic acid-induced inhibition of seed germination.

Abscisic acid (ABA) is the primary preventing factor of seed germination, which is crucial to plant survival and propagation. ABA-induced seed germination inhibition is mainly mediated by the dimeric PYR/PYL/RCAR (PYLs) family members. However, little is known about the relevance between dimeric stability of PYLs and seed germination.

Physicochemical and Rheological Properties of Degraded Konjac Gum by Abalone () Viscera Enzyme.

In the present study, a new degraded konjac glucomannan (DKGM) was prepared using a crude enzyme from abalone () viscera, and its physicochemical properties were investigated. After enzymatic hydrolysis, the viscosity of KGM obviously decreased from 15,500 mPa·s to 398 mPa·s. The rheological properties analysis of KGM and DKGMs revealed that they were pseudoplastic fluids, and pseudoplasticity, viscoelasticity, melting temperature, and gelling temperature significantly decreased after enzymatic hydrolysis, especially for KGM-180 and KGM-240.

Expression of polyphenol oxidase of Litopenaeus vannamei and its characterization.

Polyphenol oxidase (PPO) plays a critical role in decrement of shrimp quality. To obtain active PPO and elucidate its enzymatic properties, PPO from Litopenaeus vannamei (Lv-PPO) was cloned, expressed in E. coli and purified by affinity column chromatography.

Selection, identification and crystal structure of shark-derived single-domain antibodies against a green fluorescent protein.

Shark variable domain of new antigen receptors (VNARs) are the smallest naturally occurring binding domains with properties of low complexity, small size, cytoplasmic expression, and ease of engineering. Green fluorescent protein (GFP) molecules have been analyzed in conventional microscopy, but their spectral characteristics preclude their use in techniques offering substantially higher resolution. Besides, the GFP molecules can be quenched in acidic environment, which makes it necessary to develop anti-GFP antibody to solve these problems.

Properties of Pacific white shrimp (Litopenaeus vannamei) collagen and its degradation by endogenous proteinases during cold storage.

Many factors are responsible for the diminished quality of shrimp during cold storage, while the role of collagen has rarely been studied. This study therefore investigated the relationship between collagen degradation and changes of textural properties of Pacific white shrimp, and its hydrolysis by endogenous proteinases. The textural properties of shrimp decreased gradually along with disruption of shrimp muscle tissues, and the chewiness property of shrimp muscle showed a linear relationship with collagen contents in muscle during 6-day-storage at 4 °C.

Research Progresses and Applications of Fluorescent Protein Antibodies: A Review Focusing on Nanobodies.

Since the discovery of fluorescent proteins (FPs), their rich fluorescence spectra and photochemical properties have promoted widespread biological research applications. FPs can be classified into green fluorescent protein (GFP) and its derivates, red fluorescent protein (RFP) and its derivates, and near-infrared FPs. With the continuous development of FPs, antibodies targeting FPs have emerged.

Relationships of Matrix Metalloproteinase 1 and a Tissue Inhibitor of Metalloproteinase to Collagen Metabolism in .

In response to physical, chemical, and/or biological stimuli, considerable tissue self-degradation occurs in abalone, causing severe post-harvest quality loss. During this process, the extracellular matrix (ECM) is greatly degraded by endogenous proteases. The main component of the ECM is collagen, primarily type I collagen.

Hypoallergenic derivatives of heat-stable allergens alleviated food allergy symptoms in Balb/c mice.

The design of hypoallergenic derivatives is a new strategy for allergen-specific immunotherapy. Although hypoallergenic derivatives of (mud crab) heat-stable tropomyosin (TM) and myosin light chain (MLC) have been preliminarily explored, their allergenicity needs to be further studied. In this work, recombinant allergens (wtTM, wtMLC) and hypoallergenic derivatives (mtTM, mtMLC) were purified.

Identification of the Immunoglobulin E Epitope of Arginine Kinase, an Important Allergen from .

Arginine kinase (AK) was identified as an allergen in . However, little information is available about its epitopes. In this study, AK from was registered to the World Health Organization/International Union of Immunological Societies allergen nomenclature committee to be named as Cra a 2.

Screening and Characterization of Shark-Derived VNARs against SARS-CoV-2 Spike RBD Protein.

The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein is the major target for antibody therapeutics. Shark-derived variable domains of new antigen receptors (VNARs) are the smallest antibody fragments with flexible paratopes that can recognize protein motifs inaccessible to classical antibodies. This study reported four VNARs binders (JM-2, JM-5, JM-17, and JM-18) isolated from immunized with SARS-CoV-2 RBD.

IgE Epitope Analysis for Scy p 1 and Scy p 3, the Heat-Stable Myofibrillar Allergens in Mud Crab.

Tropomyosin (Scy p 1) and myosin light chain (Scy p 3) are investigated to be important heat-stable allergens in . However, the epitopes of Scy p 1 and Scy p 3 are limited. In this study, recombinant Scy p 1 and Scy p 3 had similar IgE-binding capacity to natural proteins.

Identification of linear epitopes and their major role in the immunoglobulin E-binding capacity of tropomyosin from .

Tropomyosin (TM) is an important allergen in molluscans. However, there was a lack of information about TM as an allergen in oysters. TM was purified and identified from (ATM), and its primary sequence was cloned and encoded with 284 amino acids (AAs).

Characterization, Epitope Identification, and Cross-reactivity Analysis of Tropomyosin: An Important Allergen of .

Oyster is a common shellfish product in China, which is associated with food allergy. However, there is still lack of research on allergens in oysters. In this study, tropomyosin (TM), an important allergen of , was purified and identified by mass spectrometry.

Reduction in Allergenicity and Induction of Oral Tolerance of Glycated Tropomyosin from Crab.

Tropomyosin (TM) is an important crustacean () allergen. This study aimed to assess Maillard-reacted TM (TM-G) induction of allergenic responses with cell and mouse models. We analyzed the difference of sensitization and the ability to induce immune tolerance between TM and TM-G by in vitro and in vivo models, then we compared the relationship between glycation sites of TM-G and epitopes of TM.

IgNAR antibody: Structural features, diversity and applications.

In response to the invasion of exogenous microorganisms, one of the defence strategies of the immune system is to produce antibodies. Cartilaginous fish is among those who evolved the earliest humoral immune system that utilizes immunoglobulin-type antibodies. The cartilaginous fish antibodies fall into three categories: IgW, IgM, and IgNAR.

Crystal Structure Analysis and IgE Epitope Mapping of Allergic Predominant Region in Filamin C, Scy p 9.

Filamin C (FLN c) is a novel allergen in shellfish. In this study, FLN c from was divided into three regions for recombinant expression based on the number of domains and amino acids. Using dot blot and basophil activation tests, the allergic predominant region of FLN c was determined to be 336-531 amino acid positions (named FLN c-M).

Analysis of Immunoreactivity of α/α-Tropomyosin from , Based on IgE Epitopes and Structural Characteristics.

Tropomyosin (TM) was reported to be a supercoil allergen of shellfish. However, little information is available about its link between structure and allergenicity. In this study, the subunit of TM (α-TM) and supercoil of TM (α-TM) were identified from .

Linear Epitopes Play an Important Role in the Immunoglobulin G (IgG)/Immunoglobulin E (IgE)-Binding Capacity of Scy p 4.

Sarcoplasmic calcium-binding protein is a stable allergen in and named Scy p 4. To explore the importance of linear epitopes in the immunoglobulin G (IgG)/immunoglobulin E (IgE)-binding capacity of Scy p 4, chemical denaturants were used to destroy the structure. Scy p 4 was reduced with dithiothreitol and subsequently alkylated with iodoacetamide (IAA).

Identification and characterization of arginine kinase, a novel allergen that causes cross-reactivity among shellfish.

Oyster is a common food that causes allergy. However, little information is available about its allergens and cross-reactivity. In this study, arginine kinase (AK) was identified as a novel allergen in .

Two allergens from Scylla paramamosain share common epitopes showed different allergenic potential in Balb/c mice.

Filamin C (FLN c) and triosephosphate isomerase (TIM) are novel allergens of crab (Scylla paramamosain) which are sharing common epitopes. This work aimed to assess their contributions to the induction and elicitation of allergenic responses. Balb/c mice were sensitized by intraperitoneal injections and challenged by intragastric gavage with purified proteins.

IgE epitope analysis of sarcoplasmic-calcium-binding protein, a heat-resistant allergen in .

Sarcoplasmic-calcium-binding protein (SCP) has been investigated as a novel allergen in . Nevertheless, knowledge of its effector-cell-based allergic relevance and epitopes is limited. In this study, the heat-resistant allergen SCP was able to induce significant upregulation of CD63 and CD203c ( < 0.

Effects of the Maillard reaction on the epitopes and immunoreactivity of tropomyosin, a major allergen in .

Scallop (Chlamys nobilis) causes an IgE-mediated food allergy; however, studies of the allergens in its musculus are not sufficiently comprehensive. In this context, the target protein was purified from scallops and confirmed to be the major allergen tropomyosin (TM) using proteomic technology and serological testing. Subsequently, seven potential IgE epitopes of TM were obtained using phage display technology with IgE enrichment from the serum of scallop-sensitized patients and identified via inhibition enzyme-linked immunosorbent assays.