ABSTRACT
Acanthodoras is the only genus of catfish known to secrete a conspicuous and abundant milky-looking substance through an axillary pore located just below the base of the posterior cleithral process. Despite this remarkable feature, there is no published information on the anatomical structures that produce the secretion and its possible biological/ecological functions. Dissection and histological analysis of preserved specimens of A. spinosissimus revealed the presence of a saccular axillary gland with large, binuclear secretory cells, similar to those found in other poisonous catfish. Secretory cells near the lumen appear to lose nuclei and become filled with secretory products, possibly with proteinaceous elements, as indicated by their eosinophilic appearance. As far as we know, the saccular morphology of the gland appears to constitute a unique characteristic of Acanthodoras among Doradidae catfishes. Further studies are necessary to determine the chemical composition of the secretion, as well as its possible uses by the catfish in its natural environment.
Acanthodoras é o único gênero de bagre conhecido por secretar uma substância de aparência leitosa conspícua e abundante através de um poro axilar localizado logo abaixo da base do processo cleitral posterior. Apesar dessa característica marcante, não há informações publicadas sobre as estruturas anatômicas que produzem a secreção, nem sobre suas possíveis funções biológicas/ecológicas. A dissecção e análise histológica de espécimes preservados de A. spinosissimus revelaram a presença de uma glândula axilar sacular com células secretoras binucleares, semelhantes às encontradas em outros bagres venenosos. As células secretoras próximas ao lúmen parecem perder os núcleos e são preenchidas com produtos secretores, possivelmente com elementos proteicos, conforme indicado por sua aparência eosinofílica. Até onde sabemos, a morfologia sacular da glândula parece constituir uma característica única de Acanthodoras entre os bagres Doradidae. Mais estudos são necessários para determinar a composição química da secreção, bem como seus possíveis usos pelo bagre em seu ambiente natural.
Subject(s)
Animals , Catfishes , Fish VenomsABSTRACT
ABSTRACT Acanthodoras is the only genus of catfish known to secrete a conspicuous and abundant milky-looking substance through an axillary pore located just below the base of the posterior cleithral process. Despite this remarkable feature, there is no published information on the anatomical structures that produce the secretion and its possible biological/ecological functions. Dissection and histological analysis of preserved specimens of A. spinosissimus revealed the presence of a saccular axillary gland with large, binuclear secretory cells, similar to those found in other poisonous catfish. Secretory cells near the lumen appear to lose nuclei and become filled with secretory products, possibly with proteinaceous elements, as indicated by their eosinophilic appearance. As far as we know, the saccular morphology of the gland appears to constitute a unique characteristic of Acanthodoras among Doradidae catfishes. Further studies are necessary to determine the chemical composition of the secretion, as well as its possible uses by the catfish in its natural environment.
RESUMO Acanthodoras é o único gênero de bagre conhecido por secretar uma substância de aparência leitosa conspícua e abundante através de um poro axilar localizado logo abaixo da base do processo cleitral posterior. Apesar dessa característica marcante, não há informações publicadas sobre as estruturas anatômicas que produzem a secreção, nem sobre suas possíveis funções biológicas/ecológicas. A dissecção e análise histológica de espécimes preservados de A. spinosissimus revelaram a presença de uma glândula axilar sacular com células secretoras binucleares, semelhantes às encontradas em outros bagres venenosos. As células secretoras próximas ao lúmen parecem perder os núcleos e são preenchidas com produtos secretores, possivelmente com elementos proteicos, conforme indicado por sua aparência eosinofílica. Até onde sabemos, a morfologia sacular da glândula parece constituir uma característica única de Acanthodoras entre os bagres Doradidae. Mais estudos são necessários para determinar a composição química da secreção, bem como seus possíveis usos pelo bagre em seu ambiente natural.
ABSTRACT
Lack of complete genomic data of Bothrops jararaca impedes molecular biology research focusing on biotechnological applications of venom gland components. Identification of full-length coding regions of genes is crucial for the correct molecular cloning design. Methods: RNA was extracted from the venom gland of one adult female specimen of Bothrops jararaca. Deep sequencing of the mRNA library was performed using Illumina NextSeq 500 platform. De novo assembly of B. jararaca transcriptome was done using Trinity. Annotation was performed using Blast2GO. All predicted proteins after clustering step were blasted against non-redundant protein database of NCBI using BLASTP. Metabolic pathways present in the transcriptome were annotated using the KAAS-KEGG Automatic Annotation Server. Toxins were identified in the B. jararaca predicted proteome using BLASTP against all protein sequences obtained from Animal Toxin Annotation Project from Uniprot KB/Swiss-Pro database. Figures and data visualization were performed using ggplot2 package in R language environment. Results: We described the in-depth transcriptome analysis of B. jararaca venom gland, in which 76,765 de novo assembled isoforms, 96,044 transcribed genes and 41,196 unique proteins were identified. The most abundant transcript was the zinc metalloproteinase-disintegrin-like jararhagin. Moreover, we identified 78 distinct functional classes of proteins, including toxins, inhibitors and tumor suppressors. Other venom proteins identified were the hemolytic lethal factors stonustoxin and verrucotoxin. Conclusion: It is believed that the application of deep sequencing to the analysis of snake venom transcriptomes may represent invaluable insight on their biotechnological potential focusing on candidate molecules.(AU)
Subject(s)
Animals , Bothrops , Bothrops/physiology , Proteome , Crotalid Venoms , Gene Expression Profiling , Metalloproteases , Transcriptome , Molecular Biology , Cluster Analysis , High-Throughput Nucleotide SequencingABSTRACT
Lethal factors are multifunctional oligomeric proteins found in the venomous apparatus of Scorpaeniformes fish. These toxins elicit not only an array of biological responses in vitro but also cardiovascular disorders and strong hemolytic, nociceptive and edematogenic activities in vivo. This work describes the cloning and molecular identification of two toxin subunits, denominated Sp-CTx-α and Sp-CTx-ß, from scorpionfish venom ( Scorpaena plumieri ). Methods: The primary structures were deduced after cDNA amplification by PCR with primers from conserved sequences described in Scorpaeniformes toxins. Following DNA sequencing and bioinformatic analysis, the tridimensional structures of both subunits were modeled. Results: The translated sequences (702 amino acids, each subunit) show homology with other lethal factors, while alignment between Sp-CTx-α and Sp-CTx-ß shows 54% identity. The subunits lack N-terminal signal sequences and display masses of approximately 80 kDa each. Both Sp-CTx subunits display a B30.2/SPRY domain at the C-terminal region with typically conserved motifs as described in these toxins. Secondary structure prediction identified six α-helices 18 residues long in both α and ß subunits, some of them amphiphilic with their N-terminal flanked by many basic residues, creating a cationic site associated with the cytolytic activity of these toxins. Antimicrobial potential sites were identified in Sp-CTx and share some features with other peptides presenting variable and broad-spectrum activity. A phylogenetic tree built to represent these toxins supports the proximity between scorpionfish, lionfish and stonefish. Conclusion: The study identified a putative toxin protein whose primary structure is similar to other fish toxins and with potential for production of antivenom against scorpionfish envenomation in Brazil. As a prelude to structure-function studies, we propose that the toxin is structurally related to pore-forming marine toxins.(AU)
Subject(s)
Animals , DNA, Complementary/analysis , Fish Venoms/toxicity , Peptides/analysis , Antivenins/classification , Polymerase Chain Reaction/methods , Amino Acid SequenceABSTRACT
Background: Lethal factors are multifunctional oligomeric proteins found in the venomous apparatus of Scorpaeniformes fish. These toxins elicit not only an array of biological responses in vitro but also cardiovascular disorders and strong hemolytic, nociceptive and edematogenic activities in vivo. This work describes the cloning and molecular identification of two toxin subunits, denominated Sp-CTx- and Sp-CTx-, from scorpionfish venom ( Scorpaena plumieri ). Methods: The primary structures were deduced after cDNA amplification by PCR with primers from conserved sequences described in Scorpaeniformes toxins. Following DNA sequencing and bioinformatic analysis, the tridimensional structures of both subunits were modeled. Results: The translated sequences (702 amino acids, each subunit) show homology with other lethal factors, while alignment between Sp-CTx- and Sp-CTx- shows 54% identity. The subunits lack N-terminal signal sequences and display masses of approximately 80 kDa each. Both Sp-CTx subunits display a B30.2/SPRY domain at the C-terminal region with typically conserved motifs as described in these toxins. Secondary structure prediction identified six -helices 18 residues long in both and subunits, some of them amphiphilic with their N-terminal flanked by many basic residues, creating a cationic site associated with the cytolytic activity of these toxins. Antimicrobial potential sites were identified in Sp-CTx and share some features with other peptides presenting variable and broad-spectrum activity...
Subject(s)
Animals , DNA, Complementary/analysis , Fishes, Poisonous , Fish Venoms/chemistryABSTRACT
ABSTRACT This is the first report describing morphological and histological structure of venom apparatus in Montivipera xanthina. The venom gland apparatus of M. xanthina was composed of four distinct parts, main venom gland, primary duct, accessory gland and secondary duct. The main venom gland was composed of acini. The accessory gland was formed by long and ramified tubules. Nine fangs were detected in one half of the upper jaw each at different stage of development. Only one tooth was functional and the eight remaining fangs form a replacement series. The venom apparatus of viperid snakes are the most effective venom-delivery system among vertebrates and have been the focus of scientific interests for many years. Despite this interest, there are few studies including venom-delivery system of venomous snakes. The results presented here may be common among venomous snakes and model of the viperid design of the venom apparatus.
ABSTRACT
The wolf spider Lycosa singoriensis (Laxmann, 1770) (Lycosidae: Araneae) is distributed throughout central and eastern Europe, including Russia, Kazakhistan and Turkey. This study describes the venom apparatus morphology of L. singoriensis through scanning electron microscopy (SEM). Its structure follows the general architecture observed in other spiders. Generally, a venom apparatus is composed by a pair of venom glands and chelicerae. L. singoriensis chelicerae are robust and consist of a stout basis and a movable apical segment (fang). The fang rests in a groove on the basal segment that is covered by different types of hair. L. singoriensis venom glands present equal size and measure about 4 mm in length. Each gland is enclosed by irregular muscular layers.(AU)
Subject(s)
Animals , Spider Venoms/analysis , Spiders , Weights and MeasuresABSTRACT
The phospholipase A2 superfamily encompasses 15 groups that are classified into: secreted PLA2 (sPLA2); cytosolic PLA2 (cPLA2); Ca2+-independent intracellular PLA2 (iPLA2); platelet-activating factor acetylhydrolase (PAF-AH); and lysosomal PLA2. Currently, approximately 700 PLA2 sequences are known, of which 200 are obtained from the venom gland of Crotalinae snakes. However, thus far, little information is available on cloning, purification and structural characterization of PLA2 from Crotalus durisssus cascavela venom gland. In the present work, we report the molecular cloning of a novel svPLA2 from C. d. cascavella (Cdc), a predominant rattlesnake subspecies in northeastern Brazil. The Cdc svPLA2 cDNA precursor is 689 nucleotides long and encodes a protein of 138 amino acid residues, with a calculated molecular mass of approximately 13,847 Da and an estimated isoelectric point of 5.14. Phylogenetic analysis of Crotalinae PLA2 reveals that Cdc PLA2 clustered with other acidic type IIA PLA2 homologues is also present in the venom of North American rattlesnakes. Hitherto, this study presents a novel PLA2 cDNA precursor from C. d. cascavella and data reported herein will be useful for further steps in svPLA2 purification and analysis.
Subject(s)
Animals , Male , Cloning, Molecular , Crotalid VenomsABSTRACT
The histology and ultrastructure of venom glands in the scorpion Euscorpius mingrelicus (Kessler, 1874) are described and illustrated in the current study for the first time by employing light microscopy and transmission electron microscopy (TEM). The venom apparatus is composed of a pair of venom glands and a stinger, both situated in the last segment of the metasoma. The venom glands are completely separate but similar. The two glands are segregated within the telson by striated muscle bundles, and their outer surfaces are surrounded by a cuticle. An internal layer constitutes the secretory epithelium. This epithelium is made up of simple columnar cells. The nucleus and organelles involved in cellular synthetic activity are situated basally. In the apical portion, near the gland lumen, there are many secretory granules of different sizes, shapes and electron densities.(AU)