Arginine Kinase Research Articles

Limited cross reactivity among arginine kinase allergens from mealworm and cricket edible insects.

Insects are seen as a solution to the increasing demand for protein sources for food. However, entomophagy has unfortunately been linked to allergic reactions in Europe with people with professional contacts. As mealworms (Tenebrio molitor) and crickets (Acheta domesticus) have recently become commercially available (both whole or in food formulation) in several European countries, this research assessed the cross allergenicity of arginine kinase (AK). Based on the collection of sera from a entomology laboratory staff, oven cooked insects but also purified AK fractions were tested. Immunoblotting against the protein extracts revealed different Immunoglobulin E reactivity of sera according to the insect target species: two bands (40 and 14 kDa) for crickets and a pattern including light responses at 17, 25 and 37 kDa for mealworms. Focusing on AK, low specific allergenicity was here illustrated and discussed in relation to the development of a safe edible insect consumption by humans.

Searching for Molecular Markers to Differentiate Bombus terrestris (Linnaeus) Subspecies in the Iberian Peninsula

Bumblebees (genus Bombus Latreille) are pollinator insects of great ecological and economic importance, which commercial use for pollination has increased since the 80s. However, the introduction of foreign Bombus terrestris (Linnaeus) has resulted in a decline of native bumblebee populations in Japan, Chile or Argentina among others. To study the potential introgression of commercial B. terrestris into the Iberian endemic subspecies Bombus terrestris lusitanicus Krüger, it is necessary to find a precise molecular marker that differentiates both subspecies. For this purpose, comparative analyses were carried out between B. t. lusitanicus and B. t. terrestris (Linnaeus) from Spain and from Belgium by sequencing the nuclear genes elongation factor 1-α and arginine kinase and the mitochondrial gene 16S ribosomal RNA, and genotyping with eleven microsatellite loci. No differentiation was observed at the nuclear level, but haplotypes found within the 16S sequence correlated with the morphological characterization of the subspecies. In a case study including individuals sampled before the establishment of bumblebee rearing companies and others from recent samplings, we detected hybrid individuals (those with non-matching morphological subspecies and 16S haplotype) more frequently in the south supporting the naturalization of commercial B. t. terrestris and introgression events between both subspecies. This marker should be used in Iberian populations with the aim to support management and conservation actions in endemic populations of B. t. lusitanicus.

The Microstructure, Proteomics and Crystallization of the Limpet Teeth.

Limpets are marine mollusks that use mineralized teeth, one of the hardest and strongest biomaterials, to feed on algae on intertidal rocks. However, most of studies only focus on the ultrastructure and chemical composition of the teeth while the molecular information is largely unknown, limiting our understanding of this unique and fundamental biomineralization process. The study investigates the microstructure, proteomics, and crystallization in the teeth of limpet Cellana toreuma. It is found that the limpets formed alternatively tricuspid teeth and unicuspid teeth. Small nanoneedles are densely packed at the tips or leading regions of the cusps. In contrast, big nanoneedles resembling chemically synthesized goethite are loosely packed in the trailing regions of the cusps. Proteins extracted from the whole radula, such as ferritin, peroxiredoxin, arginine kinase, GTPase-Rabs, and clathrin, are identified by proteomics. A goethite-binding experiment coupled with proteomics and RNA-seq highlights six chitin-binding proteins (CtCBPs). Furthermore, the extracted proteins from the cusps of radula or the framework chitin induce packing of crystals and possibly affect crystal polymorphs in vitro. This study provides insight into the unique biomineralization process in the limpet teeth at the molecular levels, which may guide biomimetic strategies aimed at designing hard materials at room temperature.

Towards complete identification of allergens in Jack Jumper (Myrmecia pilosula) ant venom and their clinical relevance: An immunoproteomic approach.

The venomous stings of Jack Jumper ant (JJA; species of the Myrmecia pilosula taxonomic group) are a significant public health issue in parts of south-eastern and south-western Australia, causing anaphylaxis in approximately 3% of the population. Three allergenic peptides, Myr p 1, Myr p 2 and Myr p 3, and one histamine-releasing peptide, pilosulin 5, have been fully described, but there are at least 5 additional high molecular weight IgE-binding components that have not been identified. To identify IgE-binding components in JJA venom (JJAV) and to relate the IgE recognition of these components to relevant clinical parameters. Identification of IgE-binding components and determination of their sensitizing prevalence was performed using SDS-PAGE immunoblot assay and sera from 90 patients with confirmed allergy to JJAV. Tandem mass spectrometry was used for identification of novel JJAV components fractionated by size exclusion chromatography (SEC) and SDS-PAGE. Using SDS-PAGE immunoblot, 10 IgE-binding bands were identified in JJAV, two of which were recognized by 81% and 47% of the population studied. Mass spectrometry identified 17 novel JJAV proteins, including 2 glycoproteins, and confirmed the presence of 4 known Myr p and pilosulin peptides in JJAV. Most of the newly identified IgE-binding proteins were enzymes, including phospholipase A2 , hyaluronidase, arginine kinase and dipeptidyl peptidase IV. Correlations were found between recognition of certain IgE-binding bands with JJAV-specific IgE titre by ImmunoCAP, intradermal test threshold and treatment-related issues. This study has for the first time revealed the identity of various proteins with IgE-binding capacity in the venom of JJA and demonstrated their clinical relevance in the diagnosis and treatment of JJAV allergy.

Crystal structure determination of Scylla paramamosain arginine kinase, an allergen that may cause cross-reactivity among invertebrates

Shellfish are one of the most common causes of food allergy. Arginine kinase (AK) is known as an important allergen in shellfish. In the present study, AK from crab (Scylla paramamosain) was purified and its crystal structure was determined. A comparison of AK from S. paramamosain to AKs of other species showed high amino acid sequence and secondary structure identity, while the superposition of crystal structures of AKs from different species revealed only slight differences. Similarity of the linear epitope regions among species was observed in the epitope alignment of AKs; conformational epitopes were located in the regions where secondary structure was conserved. The structure of S. paramamosain AK is an accurate template for the analysis of the IgE binding pattern, and the structure conservation and epitope similarity of AKs among species could help to inform our understanding of the cross-reactivity and contribute to the prediction of cross-reactivity related epitopes.

Ion-Exchange Chromatography Coupled With Dynamic Coating Capillary Electrophoresis for Simultaneous Determination of Tropomyosin and Arginine Kinase in Shellfish.

Tropomyosin (TM) and arginine kinase (AK) are known as two major allergens in seafood. For the first time, we demonstrate a newly developed ion-exchange chromatography coupled with dynamic coating capillary electrophoresis (IEC-DCCE) method to simultaneously analyze the TM and AK in shellfish. First, we have optimized the procedure of IEC for simple enrichment of TM and AK crude extract. By using 30 mM borate-borax at pH 9.0 with 0.3% (v/v) Tween-20 as a dynamic coating modifier for capillary electrophoresis (CE) separation, the migration time, separation efficiency and electrophoretic resolution greatly improved. The limits of detection (LOD) were 1.2 μg mL−1 for AK and 1.1 μg mL−1 for TM (S/N = 3), and the limits of quantification (LOQ) were 4.0 μg mL−1 for AK and 3.7 μg mL−1 for TM (S/N = 10). The recovery of AK ranged from 91.5 to 106.1%, while that of TM ranged from 94.0 to 109.5%. We also found that only when the concentrations of AK and TM were above LOD reported here, these proteins can stimulate human mast cell (LAD2) degranulation. Finally, the use of IEC-DCCE to analyze fresh shellfish samples highlights the applicability of this method for the simultaneous detection of these allergens in complex food systems.

Selection of Reliable Reference Genes for RT-qPCR Analysis of Bursaphelenchus mucronatus Gene Expression From Different Habitats and Developmental Stages.

Quantitative reverse transcription polymerase chain reaction (RT-qPCR), a sensitive technique for gene expression analysis, depends on the stability of the reference genes used for data normalization under different experimental conditions. Bursaphelenchus mucronatus, a pine-parasitic nematode varying in virulence, is widely distributed in natural pine forests throughout the northern hemisphere, but has not been investigated with respect to the identification of reference genes suitable for the normalization of RT-qPCR data. In the present study, eight candidate reference genes were analyzed in B. mucronatus under different habitat conditions and at different developmental stages. The expression stability of these genes was assessed by geNorm, NormFinder, BestKeeper, delta Cq, and RefFinder algorithms. In general, our results identified encoding beta-tubulin as the most stable gene. Moreover, pairwise analysis showed that three reference genes were sufficient to normalize the gene expression data under each set of conditions, with genes encoding beta-tubulin, 18S ribosomal RNA and ubiquitin-conjugating enzyme being the most suitable reference genes for different habitat conditions, whereas genes encoding beta-tubulin, histone, and 18S ribosomal RNA exhibited the most stable expression at different developmental stages. Validation of the selected reference genes was performed by profiling the expression of the fatty acid- and retinol-binding protein gene in different habitats, and by profiling the expression of the arginine kinase gene at different developmental stages. This first systematic analysis for the selection of suitable reference genes for RT-qPCR in B. mucronatus will facilitate future functional analyses and deep mining of genetic resources in this nematode.

Metabolic homeostasis: oxidative phosphorylation and the metabolic requirements of higher plants and animals.

A model of oxidative phosphorylation and its regulation is presented, which is consistent with the experimental data on metabolism in higher plants and animals. The variables that provide real-time control of metabolic status are: intramitochondrial [NAD+]/[NADH], energy state ([ATP]/[ADP][Pi]), and local oxygen concentration ([O2]). ATP consumption and respiratory chain enzyme content are tissue specific (liver vs. heart muscle), and the latter is modulated by chronic alterations in ATP consumption (i.e., endurance training etc.). ATP consumption affects the energy state, which increases or decreases as necessary to match synthesis with consumption. [NAD+]/[NADH], local [O2], and respiratory chain content determine the energy state at which match of synthesis and utilization is achieved. Tissues vary widely in their ranges of ATP consumption. Expressed as the turnover of cytochrome c, the rates may change little (7 to 12/s) (liver) or a lot (1 to >300/s) (flight muscle of birds, bats, and insects). Ancillary metabolic pathways, including creatine or arginine kinase, glycerol phosphate shuttle, fatty acid, and citric acid cycle dehydrogenases, are responsible for meeting tissue-specific differences in maximal rate and range in ATP utilization without displacing metabolic homeostasis. Intramitochondrial [NAD+]/[NADH], [ATP], and [Pi] are adjusted to keep [ADP] and [AMP] similar for all tissues despite large differences in ranges in ATP utilization. This is essential because [ADP] and [AMP], particularly the latter, have major roles in regulating the activity of many enzymes and signaling pathways (AMP deaminase, AMP dependent protein kinases, etc.) common to all higher plants and animals.NEW & NOTEWORTHY Oxidative phosphorylation has an intrinsic program that sets and stabilizes cellular energy state ([ATP]/[ADP][Pi]), and thereby metabolic homeostasis. A computational model consistent with regulation of oxidative phosphorylation in higher plants and animals is presented. Focus is on metabolism ancillary to oxidative phosphorylation by which it was integrated into preexisting metabolic regulation and adapted by evolution to develop cells and tissues with differing rates of ATP utilization: i.e., liver versus brain versus muscle.

Positive selection adaptation of two-domain arginine kinase (AK) from cold seep Vesicomyidae clams.

Arginine kinase (AK) is an important member of Phosphagen kinases which engage in energy metabolism process, and AKs from cold seep clams may develop an effective mechanism to adapt a special habitat (e.g. low temperature). Three Vesicomyidae clams and seven Veneridae clams (belong to the same Order Veneroida) were chosen to analyze the evolution of two-domain AKs. In the present study, ten two-domain AKs were identified and Neighbor-joining tree showed that AKs were divided into two groups. Branch-site model indicated that two-domain AKs were subjected to strong positive selection (ω2a = 17.5058). 16 positively selective sites were detected and five of them showed posterior probabilities of 0.95 or more. Comparative analysis found that domain 2 might be suffered from more evolutionary selection pressure than domain 1, as most positively sites were located at domain 2. Residue Pro (positively selective site) (587P in ApAK) in domain 2 from all Vesicomyidae AKs might participate in change of the synergism and in the function of its cold-adapted characteristics. In conclusion, our studies provide evidence of positive Darwinian selection in the two-domain AKs family of Vesicomyidae clams, and may contribute to a better understanding of its adaptation mechanisms to cold seep habitats.

A ‘‘turn-off’’ SERS assay for kinase detection based on arginine N-phosphorylation process

A sequential “turn-off” surface enhance Raman scattering (SERS) assay platform for the detection of protein arginine kinase McsB is constructed based on arginine N-phosphorylation process. The positive charged peptide initiates the aggregation of labelled Au nanoparticles (AuNPs) to form ‘‘Hot Spots’’, resulting to a higher SERS intensity. However, the aggregation of AuNPs could also be disbanded by the addition of McsB in which the peptides are phosphorylated on arginine residues, leading to the sharp decline of SERS signal, on account of two negative charges on the phosphate group. By this strategy, a novel ‘‘turn-off’’ SERS biosensor for McsB detection based on arginine N-phosphorylation was established with high sensitivity, selectivity and simplicity. Compared with other non-enzymatic amplification methods, the sensitivity of this newly demonstrated method was improved effectively. The detection limit for McsB is 46 pM. Besides, some controlled experiments show that the assay possesses good selectivity, which is mainly decided by the specificity of kinase. Since some kinases are important biomarkers, this assay could make great contribution in biomarkers detection in complex matrices which is based on signal amplification.

Suppressing tawny crazy ant (Nylanderia fulva) by RNAi technology.

The tawny crazy ant (Nylanderia fulva) is a new invasive pest in the United States. At present, its management mainly relies on the use of synthetic insecticides, which are generally ineffective at producing lasting control of the pest, necessitating alternative environmentally friendly measures. In this study, we evaluated the feasibility of gene silencing to control this ant species. Six housekeeping genes encoding actin (NfActin), coatomer subunit β (NfCOPβ), arginine kinase (NfArgK), and V-type proton ATPase subunits A (NfvATPaseA), B (NfvATPaseB) and E (NfvATPaseE) were cloned. Phylogenetic analysis revealed high sequence similarity to homologs from other ant species, particularly the Florida carpenter ant (Camponotus floridanus). To silence these genes, vector L4440 was used to generate six specific RNAi constructs for bacterial expression. Heat-inactivated, dsRNA-expressing Escherichia coli were incorporated into artificial diet. Worker ants exhibited reduced endogenous gene expression after feeding on such diet for 9 d. However, only ingestion of dsRNAs of NfCOPβ (a gene involved in protein trafficking) and NfArgK (a cellular energy reserve regulatory gene in invertebrates) caused modest but significantly higher ant mortality than the control. These results suggest that bacterially expressed dsRNA can be orally delivered to ant cells as a mean to target its vulnerabilities. Improved efficacy is necessary for the RNAi-based approach to be useful in tawny crazy ant management.

Seafood allergy: A comprehensive review of fish and shellfish allergens

Seafood refers to several distinct groups of edible aquatic animals including fish, crustacean, and mollusc. The two invertebrate groups of crustacean and mollusc are, for culinary reasons, often combined as shellfish but belong to two very different phyla. The evolutionary and taxonomic diversity of the various consumed seafood species poses a challenge in the identification and characterisation of the major and minor allergens critical for reliable diagnostics and therapeutic treatments. Many allergenic proteins are very different between these groups; however, some pan-allergens, including parvalbumin, tropomyosin and arginine kinase, seem to induce immunological and clinical cross-reactivity.This extensive review details the advances in the bio-molecular characterisation of 20 allergenic proteins within the three distinct seafood groups; fish, crustacean and molluscs. Furthermore, the structural and biochemical properties of the major allergens are described to highlight the immunological and subsequent clinical cross-reactivities. A comprehensive list of purified and recombinant allergens is provided, and the applications of component-resolved diagnostics and current therapeutic developments are discussed.

First comprehensive analysis of lysine acetylation in Alvinocaris longirostris from the deep-sea hydrothermal vents

BackgroundDeep-sea hydrothermal vents are unique chemoautotrophic ecosystems with harsh conditions. Alvinocaris longirostris is one of the dominant crustacean species inhabiting in these extreme environments. It is significant to clarify mechanisms in their adaptation to the vents. Lysine acetylation has been known to play critical roles in the regulation of many cellular processes. However, its function in A. longirostris and even marine invertebrates remains elusive. Our study is the first, to our knowledge, to comprehensively investigate lysine acetylome in A. longirostris.ResultsIn total, 501 unique acetylation sites from 206 proteins were identified by combination of affinity enrichment and high-sensitive-massspectrometer. It was revealed that Arg, His and Lys occurred most frequently at the + 1 position downstream of the acetylation sites, which were all alkaline amino acids and positively charged. Functional analysis revealed that the protein acetylation was involved in diverse cellular processes, such as biosynthesis of amino acids, citrate cycle, fatty acid degradation and oxidative phosphorylation. Acetylated proteins were found enriched in mitochondrion and peroxisome, and many stress response related proteins were also discovered to be acetylated, like arginine kinases, heat shock protein 70, and hemocyanins. In the two hemocyanins, nine acetylation sites were identified, among which one acetylation site was unique in A. longirostris when compared with other shallow water shrimps. Further studies are warranted to verify its function.ConclusionThe lysine acetylome of A. longirostris is investigated for the first time and brings new insights into the regulation function of the lysine acetylation. The results supply abundant resources for exploring the functions of acetylation in A. longirostris and other shrimps.

Insect (food) allergy and allergens

Insects represent an alternative for meat and fish in satisfying the increasing demand for sustainable sources of nutrition. Approximately two billion people globally consume insects. They are particularly popular in Asia, Latin America, and Africa. Most research on insect allergy has focussed on occupational or inhalation allergy. Research on insect food safety, including allergenicity, is therefore of great importance. The objective of this review is to provide an overview of cases reporting allergy following insect ingestion, studies on food allergy to insects, proteins involved in insect allergy including cross-reactive proteins, and the possibility to alter the allergenic potential of insects by food processing and digestion. Food allergy to insects has been described for silkworm, mealworm, caterpillars, Bruchus lentis, sago worm, locust, grasshopper, cicada, bee, Clanis bilineata, and the food additive carmine, which is derived from female Dactylopius coccus insects. For cockroaches, which are also edible insects, only studies on inhalation allergy have been described. Various insect allergens have been identified including tropomyosin and arginine kinase, which are both pan-allergens known for their cross-reactivity with homologous proteins in crustaceans and house dust mite. Cross-reactivity and/or co-sensitization of insect tropomyosin and arginine kinase has been demonstrated in house dust mite and seafood (e.g. prawn, shrimp) allergic patients. In addition, many other (allergenic) species (various non-edible insects, arachnids, mites, seafoods, mammals, nematoda, trematoda, plants, and fungi) have been identified with sequence alignment analysis to show potential cross-reactivity with allergens of edible insects. It was also shown that thermal processing and digestion did not eliminate insect protein allergenicity. Although purified natural allergens are scarce and yields are low, recombinant allergens from cockroach, silkworm, and Indian mealmoth are readily available, giving opportunities for future research on diagnostic allergy tests and vaccine candidates.

Diversity and phylogenetic relationships of Drilus Olivier, 1790 (Elateridae: Agrypninae: Drilini) in Cyprus

The neotenic elaterid genus Drilus Olivier, 1790 (Elateridae: Agrypninae: Drilini) contains more than 40 species distributed primarily in the Mediterranean region. The precise number of species remains ambiguous due to the insufficient taxonomic investigation in several areas. Herein, we study Drilus diversity in Cyprus and we recognize the following species: D. humeralis Pic, 1931, D. rectus Schaufuss, 1867, and D. rufipes (Baudi di Selve, 1871). Drilus testaceipes Pic, 1933 syn. nov. is synonymized under D. rectus, and D. truquii (Baudi di Selve, 1871) syn. nov. is synonymized under D. rufipes. As consequence of these taxonomic changes, Drilus humeralis remains the only species endemic to Cyprus. Females of D. rectus and D. rufipes are described and figured for the first time, as well as the larvae of D. rufipes. A key to the males of Drilus species in Cyprus is given. Drilus rectus is recorded in Syria for the first time and D. rufipes is recorded in Rhodes. To examine the phylogenetic relationships of Drilus in Cyprus, we produced the cox1-3ʹ, cox1-5′ and rrnL mtDNA sequences for available specimens of D. rectus and D. rufipes and merged them with data from GenBank. Results of the maximum likelihood analysis and Bayesian inference suggest a close relationship between D. rectus and Drilus cf. mertliki from Turkey, and a sister position of D. rufipes to a clade formed by the species from the Ionian Islands, Peloponnese, and Crete. Using the multigene barcoding approach including the above mentioned mitochondrial markers and the nuclear arginine kinase, we have been able to associate the different larval stages from Cyprus with the adult males of D. rufipes, and confirm the intraspecific variability in male body size and antennal coloration. Moreover, the low genetic difference in the cox1-3′ fragments indicates the close relationship between D. rectus populations from Cyprus and southern Turkey.

Characterization of Bacterial Arginine Kinases in Species from the Order Myxococcales

Phosphagen kinases are found in many eukaryotes and function in energy buffering within the cell through the exchange of a phosphate group between ATP and one of eight substrates (Ellington, 2001). Arginine kinases (AKs) have been identified in a few bacteria and phylogenetic analysis suggest they arrived through horizontal gene transfer (Andrews et al., 2008; Bragg et al., 2012; Suzuki et al., 2013). Recently, the bacterial AK in the well‐studied soil bacteria, Myxococcus xanthus, was knocked out and the deletion strain characterized. The results were impairment in both recovery from some forms of stress and completing a starvation induced development pathway that leads to spore formation. To update our understanding of the bacterial AKs, we conducted a BLAST search of bacterial genomes and found a total of 37 bacterial species with AKs. The majority of the bacterial AKs were deltaproteobacteria (20) with 5 in the genus Myxococcus. Interestingly, the AKs seen in the Myxococcus species seems to have arrived through two independent HGT events and thus present an opportunity to better understand how two similar evolutionary events (HGT of an AK into a soil bacterial genome) have subsequently evolved. Will the outcomes be the same or different? We will describe the biochemistry and phylogenetics of the AKs found within the deltaproteobacteria order Myxococcales.Support or Funding InformationFunding provided through 2014 NSF‐PGRP 1444539 and the Whitmore‐Williams Science Scholarship at the College of Wooster.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Local bivalve allergens

Apart from the nutritional benefits, bivalves are also considered to be among a group of allergenic foods. Symptoms of allergy to bivalves are largely similar to those of allergic reactions reported for other shellfish. The identification of allergenic proteins in a particular species is an important step for the development of more accurate allergy tests and for the definition of more effective management of patients. Currently, studies regarding the allergens in bivalve species are lacking. This minireview is an overview of local scientific articles on identification of bivalve allergens by allergenomics methods including sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis (2-DE), immunoblotting and mass-spectrometry analysis. Tropomyosin has been the only well recognized allergen in a wide range of bivalve species. In addition to tropomyosin, our local study resulted in discovery of three novel bivalve major allergens; arginine kinase (40 kDa), actin (42 kDa) and troponin C (18 kDa). This minireview will provide a better understanding of each allergen derived from local bivalves which subsequently will help in the understanding of the specific immunoglobulin E(IgE)-mediated immune response.

Screening of broad spectrum natural pesticides against conserved target arginine kinase in cotton pests by molecular modeling

Cotton is an economically important crop and its production is challenged by the diversity of pests and related insecticide resistance. Identification of the conserved target across the cotton pest will help to design broad spectrum insecticide. In this study, we have identified conserved sequences by Expressed Sequence Tag profiling from three cotton pests namely Aphis gossypii, Helicoverpa armigera, and Spodoptera exigua. One target protein arginine kinase having a key role in insect physiology and energy metabolism was studied further using homology modeling, virtual screening, molecular docking, and molecular dynamics simulation to identify potential biopesticide compounds from the Zinc natural database. We have identified four compounds having excellent inhibitor potential against the identified broad spectrum target which are highly specific to invertebrates.

Metabolic responses and arginine kinase expression of juvenile cuttlefish (Sepia pharaonis) under salinity stress

The pharaoh cuttlefish Sepia pharaonis is particularly sensitive to environmental changes in its breeding environment. The breeding of S. pharaonis larvae was carried out in different salinities for 48h, and the changes in survival rate, histological structure, energy metabolism, and anti-oxidative stress parameters were investigated and correlated with arginine kinase (AK) expression changes in muscle and liver tissues. The suitable salinity for larvae cultivation ranged from 24 to 30‰, and the survival rate showed a significant decline at 21‰ salinity. Histological observations of muscle and liver showed that changes in salinity and osmotic pressure had an adverse effect on tissue structure. Measurements of glycogen and lactic acid levels suggested that S. pharaonis could dynamically adjust energy metabolism to provide additional energy under unsuitable salinity. The protein levels and enzyme activities of AK in muscle significantly increased at 21‰ salinity. The results were consistent with prompt replenishment of phosphoarginine stores during salinity stress to maintain a dynamic ATP balance, suggesting that AK plays an important role in the regulation of energy metabolism. This study provides insight into metabolic changes during salinity stress and sheds light on the functional role of AK in S. pharaonis.

The Maillard Reaction Reduced the Sensitization of Tropomyosin and Arginine Kinase from Scylla paramamosain, Simultaneously.

The Maillard reaction was established to reduce the sensitization of tropomyosin (TM) and arginine kinase (AK) from Scylla paramamosain, and the mechanism of the attenuated sensitization was investigated. In the present study, the Maillard reaction conditions were optimized for heating at 100 °C for 60 min (pH 8.5) with arabinose. A low level of allergenicity in mice was shown by the levels of allergen-specific antibodies, and more Th1 and less Th2 cells cytokines produced and associated transcription factors with the Maillard reacted allergen (mAllergen). The tolerance potency in mice was demonstrated by the increased ratio of Th1/Th2 cytokines. Moreover, mass spectrometry analysis showed that some key amino acids of IgE-binding epitopes (K112, R125, R133 of TM; K33, K118, R202 of AK) were modified by the Maillard reaction. The Maillard reaction with arabinose reduced the sensitization of TM and AK, which may be due to the masked epitopes.