Dasyatis Akajei Research Articles

Two new and one redescribed species of Acanthobothrium(Cestoda: Onchoproteocephalidea: Onchobothriidae) from Dasyatis akajei (Myliobatiformes: Dasyatidae) in the China Sea.

Acanthobothrium ningdense n. sp. and Acanthobothrium guanghaiense n. sp. are described from the spiral intestine of the whip stingray, Dasyatis akajei (Müller & Henle). Acanthobothrium ningdense n. sp. is reported based on 38 cestode specimens collected at five locations along the Chinese coast, i.e. Taizhou, Zhejiang Province, Ningde and Xiamen, Fujian Province, Taishan, Guangdong Province and Sanya, Hainan Province between 2012 and 2015. Acanthobothrium ningdense n. sp. belongs to the "species category 4" characterised by Ghoshroy & Caira. Among category 4 Acanthobothrium species, A. ningdense n. sp. most closely resembles A. micracantha Yamaguti, 1952 and A. latum Yamaguti, 1952, both from the same host species. Acanthobothrium ningdense n. sp. differs from A. micracantha by lacking a long robust hook handle that connects the bases of medial and lateral hooks, and from A. latum by having much longer axial prongs than abaxial prongs. Acanthobothrium guanghaiense n. sp., only found in Taishan, Guangdong Province in 2014, is a category 2 Acanthobothrium species. Among category 2, A. guanghaiense n. sp. most closely resembles A. semnovesiculum Verma, 1928, but can be differentiated from it by the arrangement of testes (in two staggered columns rather than in two tandem columns), and the shape of abaxial prong (nearly straight instead of with a conspicuous curve in the proximal portion). Acanthobothrium macrocephalum Wang & Yang, 2001 is redescribed based on new specimens collected from D. akajei in Guanghai and Sanya. With this study, the total number of Acanthobothrium species reported from D. akajei is brought to nine. It is possible that some of the species of Acanthobothrium previously reported from D. akajei not encountered in this study may have geographically restricted distributions, as was observed here for A. guanghaiense n. sp..

Data for amino acid alignment of Japanese stingray melanocortin receptors with other gnathostome melanocortin receptor sequences, and the ligand selectivity of Japanese stingray melanocortin receptors

This article contains structure and pharmacological characteristics of melanocortin receptors (MCRs) related to research published in “Characterization of melanocortin receptors from stingray Dasyatis akajei, a cartilaginous fish” (Takahashi et al., 2016) [1]. The amino acid sequences of the stingray, D. akajei, MC1R, MC2R, MC3R, MC4R, and MC5R were aligned with the corresponding melanocortin receptor sequences from the elephant shark, Callorhinchus milii, the dogfish, Squalus acanthias, the goldfish, Carassius auratus, and the mouse, Mus musculus. These alignments provide the basis for phylogenetic analysis of these gnathostome melanocortin receptor sequences. In addition, the Japanese stingray melanocortin receptors were separately expressed in Chinese Hamster Ovary cells, and stimulated with stingray ACTH, α-MSH, β-MSH, γ-MSH, δ-MSH, and β-endorphin. The dose response curves reveal the order of ligand selectivity for each stingray MCR.

Characterization of melanocortin receptors from stingray Dasyatis akajei, a cartilaginous fish

Melanocortin (MC) systems are composed of MC peptides such as adrenocorticotropic hormone (ACTH), several molecular forms of melanocyte-stimulating hormones (MSHs) and MC receptors (MCRs). Here we demonstrated that the cartilaginous fish, Dasyatis akajei (stingray) expresses five subtypes of MCR genes—mc1r to mc5r—as in the case of teleost and tetrapod species. This is the first evidence showing the presence of the full repertoire of melanocortin receptors in a single of cartilaginous fish. Expression of respective stingray mcr cDNAs in Chinese hamster ovary cells revealed that Des-acetyl-α-MSH exhibited cAMP-producing activity indistinguishable to ACTH(1–24) on MC1R and MC2R, while the activity of Des-acetyl-α-MSH on MC3R, MC4R, and MC5R were similar to or slightly greater than that of ACTH(1–24). Notably, in contrast to the other vertebrates, MC2R did not require coexpression with a melanocortin receptor-2 accessory protein 1 (mrap1) cDNA for functional expression. One of the roles of MC system resides in regulation of the pituitary-interrenal (PI) axis—a homologue of tetrapod pituitary-adrenal axis. In stingray, interrenal tissues were shown to express mc2r and mc5r as major MCR genes. These results established the presence of functional PI axis in stingray at the level of receptor molecule. While MC2R participates in adrenal functions together with MRAP1 in tetrapod species, the fact that sensitivity of MC5R to Des-acetyl-α-MSH and ACTH(1–24) were two order of magnitude higher than MC2R without coexpression with MRAP1 suggested that MC5R could play a more important role than MC2R to transmit signals conveyed by ACTH and MSHs if MRAP1 is really absent in the stingray.

Three-dimensional mapping of red stingray (Dasyatis akajei) movement with reference to bottom topography

Most demersal fishes maintain strong relations with bottom substrates and bottom depths and/or topography during their lives. It is important to know these relations to for understand their lives. In Tokyo Bay, red stingray, Dasyatis akajei, classified as near-threatened species by IUCN, has increased since the 1980s. It is a top predator and engages in ecosystem engineer by mixing the sand bed surface through burring behavior, and greatly influences a coastal ecosystem. It is reported that this species invades in plage and tidal flats and has sometimes injured beachgoers and people gathering clams in Tokyo bay. Thus, it is necessary to know its behavior and habitat use to avoid accidents and to better conserve the biodiversity of ecosystems. However, previous studies have not examined its relationship with the bottom environment. This study aims to describe its behavior in relation to the bottom environment. We sounded three dimensional bottom topography of their habitat off Kaneda Cove in Tokyo Bay with interferometric sidescan sonar system and traced the movement of red stingrays by attaching a data logger system to survey their migration. The results revealed that red stingray repeated vertical movement between the surface and bottom, and used not only sand beds but also rocky beds.

Composition of glycosaminoglycans in elasmobranchs including several deep-sea sharks: identification of chondroitin/dermatan sulfate from the dried fins of Isurus oxyrinchus and Prionace glauca.

Shark fin, used as a food, is a rich source of glycosaminoglyans (GAGs), acidic polysaccharides having important biological activities, suggesting their nutraceutical and pharmaceutical application. A comprehensive survey of GAGs derived from the fin was performed on 11 elasmobranchs, including several deep sea sharks. Chondroitin sulfate (CS) and hyaluronic acid (HA) were found in Isurus oxyrinchus, Prionace glauca, Scyliorhinus torazame, Deania calcea, Chlamydoselachus anguineus, Mitsukurina owatoni, Mustelus griseus and Dasyatis akajei, respectively. CS was only found from Chimaera phantasma, Dalatias licha, and Odontaspis ferox, respectively. Characteristic disaccharide units of most of the CS were comprised of C- and D-type units. Interestingly, substantial amount of CS/dermatan sulfate (DS) was found in the dried fin (without skin and cartilage) of Isurus oxyrinchus and Prionace glauca. 1H-NMR analysis showed that the composition of glucuronic acid (GlcA) and iduronic acid (IdoA) in shark CS/DS was 41.2% and 58.8% (Isurus oxyrinchus), 36.1% and 63.9% (Prionace glauca), respectively. Furthermore, a substantial proportion of this CS/DS consisted of E-, B- and D-type units. Shark CS/DS stimulated neurite outgrowth of hippocampal neurons at a similar level as DS derived from invertebrate species. Midkine and pleiotrophin interact strongly with CS/DS from Isurus oxyrinchus and Prionace glauca, affording Kd values of 1.07 nM, 6.25 nM and 1.70 nM, 1.88 nM, respectively. These results strongly suggest that the IdoA-rich domain of CS/DS is required for neurite outgrowth activity. A detailed examination of oligosaccharide residues, produced by chondroitinase ACII digestion, suggested that the IdoA and B-type units as well as A- and C-type units were found in clusters in shark CS/DS. In addition, it was discovered that the contents of B-type units in these IdoA-rich domain increased in a length dependent manner, while C- and D-type units were located particularly in the immediate vicinity of the IdoA-rich domain.

Heterocotyle chinensis (Monogenea: Monocotylidae) from the Whip Stingray Dasyatis akajei in the Seto Inland Sea, Japan

Heterocotyle chinensis Timofeeva, 1983 (Monogenea: Monocotylidae) is reported from the gills of the whip stingray Dasyatis akajei (Muller and Henle, 1841) in the Seto Inland Sea, Hiroshima Prefecture, Japan, as a new country record. A morphological description and illustrations are provided, along with an emended key to the species of Heterocotyle. The present monogenean most likely has some tolerance for low salinity because one of the two infected fish examined was collected in brackish water.

Phylogeography and population structure of the red stingray, Dasyatis akajei inferred by mitochondrial control region

The red stingray Dasyatis akajei is distributed in both marine and freshwater, but little is known about its phylogeography and population structure. We sampled 107 individuals from one freshwater region and 6 coastal localities within the distribution range of D. akajei. Analyses of the first hypervariable region of mitochondrial DNA control region of 474 bp revealed only 17 polymorphism sites that defined 28 haplotypes, with no unique haplotype for the freshwater population. A high level of haplotype diversity and low nucleotide diversity were observed in both marine (h = 0.9393 ± 0.0104, π = 0.0069 ± 0.0040) and freshwater populations (h = 0.8333 ± 0.2224, π = 0.0084 ± 0.0063). Significant level of genetic structure was detected between four marine populations (TZ, WZ, ND and ZZ) via both hierarchical molecular variance analysis (AMOVA) and pairwise FST (with two exceptions), which is unusual for elasmobranchs detected previously over such short geographical distance. However, limited sampling suggested that the freshwater population was not particularly distinct (p > 0.05), but additional samples would be needed to confirm it. Demersal and slow-moving characters likely have contributed to the genetically heterogeneous population structure. The demographic history of D. akajei examined by mismatch distribution analyses, neutrality tests and Bayesian skyline analyses suggested a sudden population expansion dating to upper Pleistocene. The information on genetic diversity and genetic structure will have implications for the management of fisheries and conservation efforts.

Genetic diversity and population structure of the red stingray, Dasyatis akajei inferred by AFLP marker

To examine population genetic diversity and variation of the red stingray Dasyatis akajei, samples from 1 freshwater region and 6 coastal localities within its distribution range were analyzed by using amplified fragment length polymorphism (AFLP) technology. A total of 207 loci were identified by 4 primer combinations from 87 individuals, 174 of which were polymorphic (84.1%). A high level of Nei's gene diversity was observed with the overall value of 0.230 ± 0.179. No significant genealogical clusters associated with sampling sites were revealed on the UPGMA tree. Both analysis of molecular variance (AMOVA, ΦST = 0.085, P = 0.00) and pairwise FST indicated significant genetic differentiation among four marine samples. However, no particular genetic differentiation was detected between marine and the limited sampling freshwater populations (AMOVA, ΦCT = 0.056, P > 0.05). Except for the TZ vs. WZ (5.193), the gene flow estimates (Nm) demonstrated the effective immigrants were 1.918-2.976, suggesting low level dispersal between pairwise marine populations. Species-specific habits (demersal and sluggish habits) are probably responsible for the population structuring.

Characterization of acid-soluble collagens from the cartilages of scalloped hammerhead (Sphyrna lewini), red stingray (Dasyatis akajei), and skate (Raja porosa)

Acid-soluble collagen from the cartilages of scalloped hammerhead (Sphyrna lewini, ASC-S), red stingray (Dasyatis akajei, ASC-D), and skate (Raja porosa, ASC-R) were isolated with yields of 5.64±0.41, 8.72±0.31, and 6.74±0.28% on the basis of wet weight, respectively. ASC-S, ASC-D, and ASC-R had glycine as the major amino acid with contents of 220, 231, and 228 residues/1,000 residues, respectively, and contained imino acid of 174, 155, and 142 residues/1,000 residues, respectively. Three kinds of collagens more likely were comprised of 2 types of collagen (type I and II) and had some differences in primary structures. The denaturation temperatures (Tds) of the ASC-S, ASC-D, and ASC-R were 23.8, 15.1, and 12.1°C, respectively. Maximum solubility of the 3 ASCs in 0.5 M acetic acid was observed at pH 2, and a sharp decrease in solubility above 2%(w/v) was observed in the presence of NaCl. The 3 lyophilized collagens displayed loose, fibrous, and porous structures.

Complete mitochondrial genome of the red stingray Dasyatis akajei (Myliobatiformes: Dasyatidae)

We determined the complete mitochondrial genome of the red stingray Dasyatis akajei. It is 17,658 bp in length, including 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a control region. The gene arrangement and transcriptional direction were the same as those of the typical vertebrate mitogenomes. The overall base composition of the heavy-strand is 28.8% T, 26.8% C, 30.9% A and 13.6% G, with a slight A + T bias of 59.7%. The origin of light-strand replication (OL) was identified between tRNA-Asn and tRNA-Cys genes. The termination-associated sequences (TAS) and the conserved sequence blocks (CSB1-3) were identified in the control region.

Absence of post‐lesion reactive gliosis in elasmobranchs and turtles and its bearing on the evolution of astroglia

In the mature mammalian and avian central nervous systems, neuronal destructions are followed by reactive gliosis, but data on other vertebrates are rather controversial. Mammals and birds belong to different amniote groups (Synapsida and Diapsida, respectively), but exhibit common general features in their glial architecture, mainly the predominance of astrocytes. Two vertebrate groups seem to be in special positions of glial evolution: turtles (Testudiniformes) and skates and rays (Batoidea). The purely ependymoglial system of turtles seems to be the simplest one among the extant amniotes. In skates and rays, true astrocytes are preponderant glial elements, in contrast to the other "anamniotes" (and even to reptiles). We investigated stab wounds by the immunohistochemical detection of GFAP in turtles (Trachemys-formerly Pseudemys-scripta elegans), a skate (Raja clavata) and rays (Dasyatis akajei and Torpedo marmorata). Sharks (Scyliorhinus canicula) as ependymoglia-predominated chondrichthyans, and-for positive controls-rats were also studied. In the elasmobranchs, other astroglial markers: glutamine synthetase and S100 protein were also applied. Neither turtles nor elasmobranchs presented considerable astroglial reactions. Critically surveying the former reports on different vertebrates, these results complete the picture that typical post-lesion reactive gliosis is confined to mammals and birds. Analysis of the astroglial systems from phylogenetic perspective suggests that the capability of forming glial demarcation and scar formation evolved independently in mammals and birds. Predominance of astrocytes is a necessary condition but not sufficient for reactive gliosis. The intense glial reactivity of mammals and birds may be attributed to their complex cerebralization.

Status of Red Stingray (Dasyatis akajei) Livers for Japanese Specimen Banking at National Institute for Environmental Studies, Unscathed by the 2011 Tohoku Earthquake.

It is important to have a resource of environmental specimens in order to investigate changes in contaminant exposure and accumulation over time. At the National Institute for Environmental Studies in Japan, red stingray livers have been archived and the banking activity has expanded successfully since 2003. The developed standard operating procedure helps to maintain quality of the archived homogenized liver samples, and the risk management plan has helped to prevent thawing them from any incidents, including the catastrophic 2011 Tohoku earthquake. The cryogenically homogenized powdered livers will be stored in a cryogenic environment in liquid nitrogen vapor containers at -160 °C and will be analyzed when new pollutants are identified in the future.

Cloning of two members of the calcitonin-family receptors from stingray, Dasyatis akajei: Possible physiological roles of the calcitonin family in osmoregulation

In cartilaginous fish, two cDNAs encoding calcitonin-family receptors were isolated for the first time from the stingray brain. The open reading frame of one receptor cDNA coded a 525-amino acid protein. The amino acid identity of this receptor to human calcitonin-receptor-like receptor (CRLR) is 64.5%, frog CRLR is 64.7%, and flounder CRLR is 61.2% and this was higher than to human calcitonin receptor (CTR) (46.1%), frog CTR (54.7%), and flounder CTR (48.9%). We strongly suggested that this receptor is a ray CRLR based on phylogenetic analysis. In case of the second receptor, amino acid identity among CRLRs (human 50.5%, frog 50.7%, flounder 48.0%) and CTRs (human 43.2%, frog 49.1%, flounder 41.8%) was similar. From phylogenetic analysis of both CRLRs and CTRs, we believe that this receptor is ray CTR. The expression of ray CRLR mRNA was predominantly detected in the nervous system (brain) and vascular system (atrium, ventricle, and gill), which reflects the similar localization of CGRP in the nervous and vascular systems as mammals. It was observed that the second receptor was expressed in several tissues, namely cartilage, brain, pituitary gland, gill, atrium, ventricle, pancreas, spleen, liver, gall bladder, intestine, rectal gland, kidney, testis and ovary. This localization pattern was very similar to flounder CTR. Both receptor mRNAs were strongly expressed in the gill. This suggests that the calcitonin-family members are involved in the osmoregulation of stingray as this fish is known to be euryhaline. When a stingray was transferred to diluted seawater (20% seawater), the expression of both receptors significantly decreased in the gill. Similar results were obtained in the kidney of the stingray. Thus, our cloning and isolation of both receptors in the stingray will be helpful for elucidation of their physiological role(s) such as osmoregulation including calcium metabolism of cartilaginous fish.

Free-living stages of three species of parasitic copepods (Siphonostomatoida, Eudactylinidae) reared from eggs, with discussion on the ontogenetic features in the Siphonostomatoida

Five naupliar stages and the infective copopodid stage of Eudactylina dasiati Izawa, 2011, Dangoka japonica Izawa, 2011, and an unidentified eudactylinid species are described based on free-living larvae reared from eggs detached from ovigerous females, which were recovered from the branchial lamellae of Japanese elasmobranchs, Dasyatis akajei (Muller & Henle, 1841) (Dasyatidae), Rhinobatos schlegelii Muller & Henle, 1841 (Rhinobatidae), and Alopias vulpine (Bonnaterre, 1788) (Alopiidae), respectively. These species of Eudactylinidae, along with Gangliopus pyriformis Gerstaecker, 1854 (Pandaridae) are the only Siphonostomatoida known to have five naupliar stages prior to the infective copepodid I. Naupliar morphology and the antennular segmentation in the Siphonostomatoida are discussed. Siphonostomatoid nauplii may possess six caudal elements and limb buds of the maxillae, maxillipeds, and two legs, but not maxillules. In the Siphonostomatoida, the naked first antennular segment of the nauplius may be retained to the adult stage.

Characteristics and Kinetics of Iron Releasefrom the Ferritin under the EGCG reduction

The mechanism of iron release from ferritin in vivo is still unclear even though it represents a key step of the metabolism of iron in vivo. Here, both interaction intensity and binding stability between epigallocatechin gallate (EGCG) from tea and liver ferritin of Dasyatis akajei (DALF) were investigated using UV-visible, fluorescence and circular dichroism (CD) spectrometry, respectively. The results indicated that EGCG could reduce the iron within the ferritin shell directly in the absence of chemical reducers such as Na(2)S(2)O(4), but this process was strictly pH-dependent, and the rate of iron release is faster at low pH than at high pH. The kinetic study of iron release showed that this process fitted the law of zero order reaction, which differed from that of first order reaction by various chemical reducers such as Vitamin C. In addition, Both fluorescence and CD spectrometry were further used to study the reduction mechanism of iron release in vitro, showing that there was a slight conformation change of the ferritin shell during EGCG reduction because of a complex formation of DALF-EGCG. It appears that chemical reducers with large molecular sizes reduce the iron across the protein shell by the way of an electron transfer pathway (ETP). A novel pathway for iron release from DALF with EGCG reduction is suggested to explain for a reductive route of iron metabolism by biological reducers in vivo.

Mass spectrometric characteristics and kinetics of iron release in visceral mass of Saccostrea cucullata

Ferritins with electrophoretic homogeneity were prepared from the visceral mass of Saccostrea cucullata in batch. The native PAGE approach showed similar electrophoretic mobility among pig pancreatic ferritin, liver ferritin of Dasyatis akajei, and visceral mass ferritin of Saccostrea cucullata. SDS-PAGE indicated that the Saccostrea cucullata visceral ferritin (SCVF) consisted of a single subunit type and had a molecular weight (MW) of approximately 20 kDa, suggesting that the protein shell in SCVF was composed of a single subunit. In addition, peptide mass fingerprinting and transmission electron microscopy were used to identify SCVF further, and to observe its molecular structure. We found that the molecular structure in SCVF was similar to that of most mammalian ferritins, which are composed of a protein shell and an iron core. The results of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry under the assistance of an acidic matrix, sinapic acid, also showed that SCVF was composed of a single subunit type and its subunit MW was calculated to be 19871.042 Da in the absence of heme. Kinetics analysis revealed that the complete process of iron release fitted the law of a first-order reaction, which is similar to that of most ferritins in mammals. Similar to bacterial ferritin, studies indicated that the shell consisted of a single subunit type and showed similar kinetics of iron release, suggesting that this subunit plays two important roles in iron release and storage, and that it shows different stability and intensity of interaction in carrying out its physiological functions in SCVF.

Five New Species of Eudactylina Van Beneden, 1853 (Copepoda, Siphonostomatoida, Eudactylinidae) Parasitic on Japanese Elasmobranchs

AbstractFive new species of the genus Eudactylina are described based on specimens recovered from the branchial lamellae of six species of Japanese elasmobranchs. These are E. musteli nov. sp. from Mustelus griseus Pietschmann, 1908 (Triakidae), E. squatini nov. sp. from Squatina japonica Bleeker, 1858 (Squatinidae), E. dasyati nov. sp. from Dasyatis akajei (Müller & Henle, 1841) and Taeniura meyeni Müller & Henle, 1841 (Dasyatidae), E. taeniuri nov. sp. from T. meyeni, and E. gymnuri nov. sp. from Gymnura japonica (Temminck & Schlegel, 1850) (Gymnuridae). The males of four new species and the copepodid stages IV and V of E. gimnuri nov. sp. are described. Segment formation of the abdomen in the late copepodid stages of this genus and a peculiar process of the 1st endopodal segment of the male leg 2 are discussed.

Purification and Characterization of Parvalbumins, the Major Allergens in Red Stingray (Dasyatis akajei)

Fish has received increasing attention because it induces IgE-mediated food allergy. Parvalbumin (PV) represents the major allergen of fish, and IgE cross-reactivity to PV in various teleost fish species has been shown, while little information is available about allergens in elasmobranch fish. In this study, two PV isoforms (named as PV-I and PV-II) from red stingray (Dasyatis akajei) were purified to homogeneity by a series of procedures including ammonium sulfate precipitation and column chromatographies of DEAE-Sepharose and Sephacryl S-200. Purified PVs revealed a single band on tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular masses of PV-I and PV-II were 12.29 and 11.95 kDa, respectively, as determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Western blot using antifrog PV monoclonal antibody (PARV-19) showed positive reactions to the two proteins, confirming that they were PVs, although their immunological reactivities were weaker than those of PV from silver carp. The N-terminal amino acid sequence of PV-I was determined, and comparison with PVs from other fish species showed low homology between teleost and elasmobranch fish. The isoelectric points of PV-I and PV-II were 5.4 and 5.0, respectively, as determined by two-dimensional electrophoresis (2-DE), suggesting that both isoforms belong to the α-group. IgE immunoblotting analysis showed that sera from fish-allergic patients reacted to both PV-I and PV-II from red stingray. Thermal stability revealed that PV-I easily formed oligomers than PV-II, which might contribute to the maintenance of its allerginicity during heat processing.

A Stingray, Dasyatis akajei, with Aberrant Pectoral Fins from the Japan Sea

A Stingray, Dasyatis akajei, with Aberrant Pectoral Fins from the Japan Sea

GELATINOLYTIC SERINE PROTEINASES FROM THE WING MUSCLE OF RED STINGRAY

ABSTRACT Four gelatinolytic proteinases (A1, 97 kDa; A2, 66 kDa; A3, 30 kDa; A4, 23 kDa) were detected from the red stingray wing muscle by gelatin zymography. Among these proteinases, major gelatinolytic proteinases (A1, A2) were more purified and examined their characters. The optimum pH and temperature for the gelatinolytic activity of A1 and A2 were around pH 7 and pH 8, and maximal activity of A1 is at 30–50C, that of A2 is at 30C. Also, they were demonstrated to hydrolyze the gelatin from red stingray; protein bands were almost completely degraded after 6 h incubation at 37C and pH 7.5. Both enzymes were strongly inhibited by Pefabloc SC, which suggests that they belong to gelatinolytic serine protease. PRACTICAL APPLICATIONS Gelatinolytic enzyme hydrolyzes denatured collagen such as gelatin. The enzymes from red stingray may be utilized to produce gelatin peptide, which has been widely used as additive to enhance the elasticity, consistency and stability of food products. In addition, it is meaningful in that this study will give information to understand the gelatinolytic proteinases in ray species and could lead to a comparative study of the biochemical properties of gelatinolytic proteinases in elasmobranch and many other species.