Edible Frog Research Articles

Identification of Miscellaneous Peptides from the Skin Secretion of the European Edible Frog, Pelophylax kl. Esculentus.

The chemical compounds synthesised and secreted from the dermal glands of amphibian have diverse bioactivities that play key roles in the hosts' innate immune system and in causing diverse pharmacological effects in predators that may ingest the defensive skin secretions. As new biotechnological methods have developed, increasing numbers of novel peptides with novel activities have been discovered from this source of natural compounds. In this study, a number of defensive skin secretion peptide sequences were obtained from the European edible frog, P. kl. esculentus, using a 'shotgun' cloning technique developed previously within our laboratory. Some of these sequences have been previously reported but had either obtained from other species or were isolated using different methods. Two new skin peptides are described here for the first time. Esculentin-2c and Brevinin-2Tbe belong to the Esculentin-2 and Brevinin-2 families, respectively, and both are very similar to their respective analogues but with a few amino acid differences. Further, [Asn-3, Lys-6, Phe-13] 3-14-bombesin isolated previously from the skin of the marsh frog, Rana ridibunda, was identified here in the skin of P. kl. esculentus. Studies such as this can provide a rapid elucidation of peptide and corresponding DNA sequences from unstudied species of frogs and can rapidly provide a basis for related scientific studies such as those involved in systematic or the evolution of a large diverse gene family and usage by biomedical researchers as a source of potential novel drug leads or pharmacological agents.

Identification and bioactivity evaluation of two novel temporins from the skin secretion of the European edible frog, Pelophylax kl. esculentus

The amphibian temporins, amongst the smallest antimicrobial peptides (AMPs), are α-helical, amphipathic, hydrophobic and cationic and are active mainly against Gram-positive bacteria but inactive or weakly active against Gram-negative bacteria. Here, we report two novel members of the temporin family, named temporin-1Ee (FLPVIAGVLSKLFamide) and temporin-1Re (FLPGLLAGLLamide), whose biosynthetic precursor structures were deduced from clones obtained from skin secretion-derived cDNA libraries of the European edible frog, Pelophylax kl. esculentus, by ‘shotgun’ cloning. Deduction of the molecular masses of each mature processed peptide from respective cloned cDNAs was used to locate respective molecules in reverse-phase HPLC fractions of secretion. Temporin-1Ee (MIC = 10 μM) and temporin-1Re (MIC = 60 μM) were both found to be active against Gram-positive Staphylococcus aureus, but retaining a weak haemolytic activity. To our knowledge, Single-site substitutions can dramatically change the spectrum of activity of a given temporin. Compared with temporine-1Ec, just one chemically-conservative substitution (Val8 instead of Leu8), temporin-1Ee bearing a net charge of +2 displays broad-spectrum activity with particularly high potency on the clinically relevant Gram-negative strains, Escherichia coli (MIC = 40 μM). These factors bode well for translating temporins to be potential drug candidates for the design of new and valuable anti-infective agents.

Repeated Detection of an Invertebrate Iridovirus in Amphibians

Abstract Invertebrate iridoviruses (IIVs) (family: Iridoviridae) are known pathogens for invertebrates, causing high mortality and reduced fertility in affected insects. Over the past two decades, IIVs have also been increasingly found in lizards in association with nonspecific clinical signs. It has been hypothesized that IIVs from insects can also infect reptiles. From 2010–11, IIVs were repeatedly detected via polymerase chain reaction testing and virus isolation methods in routine diagnostic samples from different amphibians: three blue poison dart frogs (Dendrobates tinctorius azureus), four edible frogs (Pelophylax kl. esculentus), a giant ditch frog (Leptodactylus fallax), an Amazon milk frog (Trachycephalus resinifictrix), mixed organs from agile frogs (Rana dalmatina), a black-spined toad (Bufo melanostictus), and one Lake Urmia newt (Neurergus crocatus). IIVs were found in skin swabs from apparently healthy animals, as well as in multiple organs of frogs that died of unknown causes. Prey insects...

Cadmium Bio-Accumulation and the Associated Biomarkers in Edible Frog Species (Hoplobatrachus Occipitalis) in Ibadan, Oyo State, Nigeria

Cadmium Bio-Accumulation and the Associated Biomarkers in Edible Frog Species (Hoplobatrachus Occipitalis) in Ibadan, Oyo State, Nigeria

Materials for the helminth fauna of the edible frog Pelophylax esculentus (Linnaeus, 1758) in the Volga basin

The work provides information on helminthes of the edible frog Pelophylax esculentus (Linnaeus, 1758) from different regions of the Volga basin on the basis of autopsy of 24 individuals caught in 2005, 2007, and 2010–2015 on the territory of Samara region, Tatarstan and Mari El Republic. The list of parasitic worms includes 16 species from two classes: 14 Trematoda and 2 Nematoda. Among helminthes at the marita stage of Trematodes (11 species) transmitted with food dominated due to the frog’s predation on small aquatic invertebrates and cannibalism. The proportion of larval stages of trematodes (4) and nematodes not circulating on trophic chains (1) was insignificant. Refs 24. Tables 1.

Low salinity increases survival, body weight and development in tadpoles of the Chinese edible frogHoplobatrachus rugulosus

Water salinity affects survival, growth and metamorphosis of anuran tadpoles. Hoplobatrachus rugulosus is considered not only as a freshwater amphibian but is also found in brackish wetlands. However, whether salinity change interferes with hatching, survival, body mass and development of H. rugulosus tadpoles is unknown. We found that salinity levels of <4‰ did not affect of survival or hatching of H. rugulosus eggs. At an early larval stage, tadpoles could tolerate up to 9‰ salinity for 96 h; however, body water content decreased when salinity was >5‰. After a 3-week experiment, body weights of tadpoles exposed to 2‰ and 4‰ salinities were higher but that of the 6‰ group was lower compared with the 0‰ group. More than 90% of tadpoles exposed to 2‰ and 4‰ salinity showed complete metamorphosis. Salinity levels <4‰ promoted survival of tadpoles better than 0‰, whereas none of tadpoles in the 6‰ group became juvenile frogs in 50 days. Time taken to reach metamorphosis was shorter for 2‰ and 4‰ (47.22 ± 0.28 and 47.26 ± 0.33 days, respectively) than for 0‰ (49.31 ± 0.35 days). Juvenile frogs in the 2‰ group had greater body weight than the control. It could be concluded that salinity of <4‰ increased survival and body weight of H. rugulosus tadpoles, and shortened the time taken to reach metamorphosis.

Spatial behavior in relation to mating systems: movement patterns, nearest-neighbor distances, and mating success in diploid and polyploid frog hybrids (Pelophylax esculentus)

Mating success depends not only on genetic and phenotypic characteristics of males and females but also on their spatial position relative to other individuals, which influences the chances for interactions. Hence, any behavior that affects proximity to other individuals can potentially translate into fitness gain or loss. Here, we investigate the effects of genotype on male movement and distance to nearest neighbor (DNN) in three populations of the edible frog Pelophylax esculentus, a natural hybrid between its parental species Pelophylax ridibundus (genotype RR) and Pelophylax lessonae (LL). The system is particularly suited for such an analysis because the fitness differences between mating with a certain genotype are particularly strong. Moreover, which genotype should be preferred differs among populations where diploid hybrids (LR) live in sympatry with P. lessonae (L–E system) and those where diploid hybrids occur in all-hybrid populations together with triploids (LLR and/or LRR) (E–E system). Hence, we expected differences among genotypes in movement patterns and spatial arrangement within the breeding pond. We did, indeed, find such differences. They were predominantly due to density differences between populations, followed by size and condition differences between males. Most relevant for our question was a difference in DNN: in the E–E system, distances between all three hybrid types were equal, whereas in the L–E system LR hybrids tended to stay closer to LL than to other LR. The results are discussed in relation to previous mate choice experiments and theoretical models about mating preferences in the two systems.

Variability of Structural and Biomechanical Parameters of Pelophylax Esculentus (Amphibia, Anura) Limb Bones

Abstract Variability of Structural and Biomechanical Prameters of Pelophylax esculentus (Amphibia, Anura) Limb Bones. Broshko Ye. O. — Structural and biomechanical parameters of Edible Frog, Pelophylax esculentus (Linnaeus, 1758), limb bones, namely, mass, linear dimensions, parameters of the shaft’s cross-sectional shape (cross-sectional area, moments of inertia, radiuses of inertia) were investigated. Some coefficients were also estimated: diameters ratio (df/ds), cross-sectional index (ik), principal moments of inertia ratio (Imax/Imin.). Coefficients of variation of linear dimensions (11.9-20.0 %) anrelative bone mass (22-35 %) were established. Moments of inertia of various bones are more variable (CV = 41.67-56.35 %) in relation to radii of inertia (CV = 9.68-14.67 %). Shaft’s cross-sectional shape is invariable in all cases. However, there is high individual variability of structural and biomechanical parameters of P. esculentus limb bones. Variability of parameters was limited by the certain range. We suggest the presence of stable norm in bone structure. Stylopodium bones have the primary biomechanical function among the elements of limb skeleton, because their parameters most clearly responsive to changes in body mass.

High levels of prevalence related to age and body condition: host-parasite interactions in a water frog Pelophylax kl. hispanicus

Host traits can significantly influence patterns of infection and disease. Here, we studied the helminths par - asitizing the Italian edible frog Pelophylax kl. hispanicus, giving special attention to the relationship between parasites and host traits such as sex, snout vent length, weight and body condition. The helminth community was composed of seven species: three trematode species (Diplodiscus subclavatus, Gorgodera cygnoides, Pleurogenes claviger), three nematode species (Icosiella neglecta, Oswaldocruzia filiformis , Rhabdias sp.) and one acanthocephalan species (Pom phorhychus laevis). We found that prevalence was positively correlated with snout-vent length and weight, but did not differ with body condition or sex. We found that prevalence and mean species richness increased with age. Our results show that abundance of Icosiella neglecta was positively correlated with higher values for host body condition. In fact, we found that high prevalence and mean species richness do not necessarily imply poorer body condition in the para- sitized host. In conclusion, our results show that the helminth community in this taxon has great diversity, and this host-parasite system seems to be evolved to low levels of virulence, helminths maintaining a commensal relationship with this frog.

Pesticides alter ion transport across frog (Pelophylax kl. esculentus) skin

We have measured, in the edible frog (Pelophylax kl. esculentus), the effect of two fungicides (8-hydroxyquinoline and captan), and four herbicides (DCMU, glyphosate, paraquat, and propachlor) on the short-circuit current, whose value gives an estimate of the net ion transport taking place across isolated skin. Glyphosate and paraquat treatment produced a modest increase in short-circuit current, corresponding to 2.6±0.7 and 4.6±0.8 μA·cm−2, whereas the other substances had a more sustained effect, ranging from 9.1±0.6 (propachlor) to 14.8±0.9 μA·cm−2 (captan), which is mainly attributable to an increase in the Na+ absorption, and, to a lesser extent, Cl− secretion. The increase in short-circuit current after pesticide treatment, was partially abolished by AF12198, indomethacin, SC58125, SQ 22536, and W7; these results suggest that pesticides, independently from their chemical structure, induce the release of interleukin-1, which triggers the activity of cyclooxygenase-2, whose products, via a concentration in intracellular cAMP and Ca2+ concentration, increase Na+ absorption. The resulting Na+ disequilibrium must be compensated for by other epithelia, with the only consequence being the dissipation of energy. However, our results are important because they indicate that pesticides interact with the basic cellular machinery, which is responsible for the myriad of biological functions of different cell types.

Are invasive marsh frogs (Pelophylax ridibundus) replacing the native P. lessonae/P. esculentus hybridogenetic complex in Western Europe? Genetic evidence from a field study

The water-frog L–E system, widespread in Western Europe, comprises the pool frog Pelophylax lessonae and the hybridogenetic edible frog P. esculentus, which originated from hybridization between pool frogs and marsh frogs (P. ridibundus). In P. esculentus, the lessonae (L) genome is eliminated during meiosis and has to be gained anew each generation from a P. lessonae partner, while the ridibundus (R′) genome is transmitted clonally. It therefore accumulates deleterious mutations, so that R′R′ offspring from P. esculentus×P. esculentus crosses are normally unviable. This system is now threatened by invasive P. ridibundus (RR) imported from Eastern Europe and the Balkans. We investigated the genetic interactions between invasive marsh frogs and native water frogs in a Swiss wetland area, and used genetic data collected in the field to validate several components of a recently postulated mechanism of species replacement. We identified neo-ridibundus individuals derived from crosses between invasive ridibundus and native esculentus, as well as newly arisen hybridogenetic esculentus lineages stemming from crosses between invasive ridibundus (RR) and native lessonae (LL). As their ridibundus genomes are likely to carry less deleterious mutations, such lineages are expected to produce viable ridibundus offspring, contributing to species replacement. However, such crosses with invasive ridibundus only occurred at a limited scale; moreover, RR×LL crosses did not induce any introgression from the ridibundus to the lessonae genome. We did not find any ridibundus stemming from crosses between ancient esculentus lineages. Despite several decades of presence on the site, introduced ridibundus individuals only represent 15 % of sampled frogs, and their spatial distribution seems shaped by specific ecological requirements rather than history of colonization. We therefore expect the three taxa to coexist stably in this area.

Cytological maps of lampbrush chromosomes of European water frogs (Pelophylax esculentuscomplex) from the Eastern Ukraine

BackgroundHybridogenesis (hemiclonal inheritance) is a kind of clonal reproduction in which hybrids between parental species are reproduced by crossing with one of the parental species. European water frogs (Pelophylax esculentus complex) represent an appropriate model for studying interspecies hybridization, processes of hemiclonal inheritance and polyploidization. P. esculentus complex consists of two parental species, P. ridibundus (the lake frog) and P. lessonae (the pool frog), and their hybridogenetic hybrid – P. esculentus (the edible frog). Parental and hybrid frogs can reproduce syntopically and form hemiclonal population systems. For studying mechanisms underlying the maintenance of water frog population systems it is required to characterize the karyotypes transmitted in gametes of parental and different hybrid animals of both sexes.ResultsIn order to obtain an instrument for characterization of oocyte karyotypes in hybrid female frogs, we constructed cytological maps of lampbrush chromosomes from oocytes of both parental species originating in Eastern Ukraine. We further identified certain molecular components of chromosomal marker structures and mapped coilin-rich spheres and granules, chromosome associated nucleoli and special loops accumulating splicing factors. We recorded the dissimilarities between P. ridibundus and P. lessonae lampbrush chromosomes in the length of orthologous chromosomes, number and location of marker structures and interstitial (TTAGGG)n-repeat sites as well as activity of nucleolus organizer. Satellite repeat RrS1 was mapped in centromere regions of lampbrush chromosomes of the both species. Additionally, we discovered transcripts of RrS1 repeat in oocytes of P. ridibundus and P. lessonae. Moreover, G-rich transcripts of telomere repeat were revealed in association with terminal regions of P. ridibundus and P. lessonae lampbrush chromosomes.ConclusionsThe constructed cytological maps of lampbrush chromosomes of P. ridibundus and P. lessonae provide basis to define the type of genome transmitted within individual oocytes of P. esculentus females with different ploidy and from various population systems.

Novel insights into the genetic diversity of Balantidium and Balantidium-like cyst-forming ciliates.

Balantidiasis is considered a neglected zoonotic disease with pigs serving as reservoir hosts. However, Balantidium coli has been recorded in many other mammalian species, including primates. Here, we evaluated the genetic diversity of B. coli in non-human primates using two gene markers (SSrDNA and ITS1-5.8SDNA-ITS2). We analyzed 49 isolates of ciliates from fecal samples originating from 11 species of captive and wild primates, domestic pigs and wild boar. The phylogenetic trees were computed using Bayesian inference and Maximum likelihood. Balantidium entozoon from edible frog and Buxtonella sulcata from cattle were included in the analyses as the closest relatives of B. coli, as well as reference sequences of vestibuliferids. The SSrDNA tree showed the same phylogenetic diversification of B. coli at genus level as the tree constructed based on the ITS region. Based on the polymorphism of SSrDNA sequences, the type species of the genus, namely B. entozoon, appeared to be phylogenetically distinct from B. coli. Thus, we propose a new genus Neobalantidium for the homeothermic clade. Moreover, several isolates from both captive and wild primates (excluding great apes) clustered with B. sulcata with high support, suggesting the existence of a new species within this genus. The cysts of Buxtonella and Neobalantidium are morphologically indistinguishable and the presence of Buxtonella-like ciliates in primates opens the question about possible occurrence of these pathogens in humans.

Long-term study of an infection with ranaviruses in a group of edible frogs (Pelophylax kl. esculentus) and partial characterization of two viruses based on four genomic regions

Several edible frogs (Pelophylax kl. esculentus) collected into a single group from various ponds in Europe died suddenly with reddening of the skin (legs, abdomen) and haemorrhages in the gastrointestinal tract. Ranavirus was detected in some of the dead frogs using PCR, and virus was also isolated in cell culture. Over the following 3years, another two outbreaks occurred with low to high mortality in between asymptomatic periods. In the first 2years, the same ranavirus was detected repeatedly, but a new ranavirus was isolated in association with the second mass-mortality event.The two different ranaviruses were characterized based on nucleotide sequences from four genomic regions, namely, major capsid protein, DNA polymerase, ribonucleoside diphosphate reductase alpha and beta subunit genes. The sequences showed slight variations to each other or GenBank entries and both clustered to the Rana esculenta virus (REV-like) clade in the phylogenetic analysis. Furthermore, a quiescent infection was demonstrated in two individuals. By comparing samples taken before and after transport and caging in groups it was possible to identify the pond of origin and a ranavirus was detected for the first time in wild amphibians in Germany.

The prevalence, antimicrobial resistance and PFGE profiles of Laribacter hongkongensis in retail freshwater fish and edible frogs of southern China

Laribacter hongkongensis is a novel emerging pathogen associated with human gastroenteritis. We aimed to investigate the prevalence, antimicrobial resistance and genotypic relationship of 199 L. hongkongensis isolates from 690 intestinal samples of fish and frogs. These samples were collected from retail markets in the city of Guangzhou in southern China from October 2008 to September 2009. L. hongkongensis was detected in from 80 (16.3%) out of 490 freshwater fish, and this number included 76 (32.3%) out of 235 grass carp and 4 (14.8%) out of 27 bighead carp. A higher isolation rate of 59.5% (119 out of 200) was observed in edible frogs. The isolation rate was highest in the spring in comparison with other seasons. Notably, 63.8% of the isolates were resistant to at least one class of antimicrobial agents. Analysis by pulsed-field gel electrophoresis (PFGE) revealed that the isolates could be grouped into three clusters. Isolates from fish intestines were grouped into two clusters: cluster I and II. Isolates of frog-origin and several fish-origin isolates were grouped into cluster III. Two patient-derived strains could be classed into cluster III. Extensive genetic heterogeneity among the isolates was observed. The results indicate that L. hongkongensis isolates exhibits host tropism, extensive resistance to widely used antimicrobials and diverse biological evolution in an aquatic environment. The frog is more likely than the freshwater fish to be the potential source for human infection with L. hongkongensis.

Nutritive Potentials of Male and Female Edible Frog (Pelophylax esculentus) II: Selected Trace Elements and Functional Properties

Some trace elements; nickel (Ni), lead (Pb), zinc (Zn), cadmium (Cd), copper (Cu), selenium (Se), chromium (Cr) and functional properties of meat from male and female edible frog (EF) were determined using standard methods of analysis. The male and female EF contained the following trace elements in μg/100g; Ni (14.75 ± 0.20 and 12.60 ± 0.50), Pb (8.10 ± 0.05 and 7.64 ± 0.02), Zn (20.15 ± 0.05 and 26.20 ± 0.01), Cr (4.20 ± 0.01 and 4.05 ± 0.01), Cd (0.92 ± 0.01 and 0.88 ± 0.02) and Se (2.84 ± 0.01 and 3.25 ± 0.05) respectively. The functional properties (%) were water absorption capacity WAC (118.20 ± 0.02 and 125.10 ± 0.01), fat absorption capacity FAC (235.50± 0.01 and 242.60± 0.02), fat emulsion capacity FEC (92.10± 0.02 and 95.40± 0.05), foaming capacity FC (34.15±0.05 and 37.50± 0.04) and least gelation capacity LGC (12.00±0.01 and 11.50±0.02) respectively in male and female EF. The results suggest that meat from both male and female EF are safer for consumption due to the concentrations of trace elements compared to the recommended daily allowances (RDA) and would also be useful in other industrial applications especially in food formulation.

Grazing on toxic cyanobacterial blooms by tadpoles of edible frog Rana grylio

SUMMARYTadpoles of Rana grylio were raised as edible frogs in fishponds of Guanqiao in Wuhan City, Hubei, China, during cyanobacterial blooms from June to October. The dominant cyanobacterial species was Microcystis, which was found to be lethally toxic by intraperitoneal (i.p.) mouse bioassay. Little is known about the effect of tadpoles on toxic cyanobacterial blooms. To evaluate the potential of the tadpoles to graze on cyanobacterial blooms, the tadpoles were fed on Microcystis collected from the field in the laboratory. The Microcystis cells decreased from 1.19 × 107 cells mL−1 to 3.23 × 106 cells mL−1, with a sharp reduction of 73% of the initial Microcystis population observed in the first 24 h after introduction of the tadpoles. The ponds containing tadpoles had a markedly lower density of Microcystis than those lacking tadpoles. Tadpoles exposed to either cultured Microcystis aeruginosa (NIES–90, 2.768 µg microcystins mg–1 dw–1) cells or lysed M. aeruginosa cells grew well, however, indicating that they were unaffected by Microcystis toxins. We found a significant increase in tadpole body weight after feeding on either field Microcystis or cultured M. aeruginosa. The mean increase in individual body weight was 20 mg day−1 when fed on Microcystis from the pond, and 7 mg day−1 when fed on M. aeruginosa from culture. Our study strongly suggested that there is a direct trophic relationship between R. grylio tadpoles and toxic Microcystis blooms and they possess the potential to graze on toxic Microcystis. The results imply that R. grylio tadpoles may play an important ecological role in reducing toxic cyanobacterial blooms caused by Microcystis.

Crossbridge and filament compliance in muscle: implications for tension generation and lever arm swing

The stiffness of myosin heads attached to actin is a crucial parameter in determining the kinetics and mechanics of the crossbridge cycle. It has been claimed that the stiffness of myosin heads in the anterior tibialis muscle of the common frog (Rana temporaria) is as high as 3.3pN/nm, substantially higher than its value in rabbit muscle (~1.7pN/nm). However, the crossbridge stiffness measurement has a large error since the contribution of crossbridges to half-sarcomere compliance is obtained by subtracting from the half-sarcomere compliance the contributions of the thick and thin filaments, each with a substantial error. Calculation of its value for isometric contraction also depends on the fraction of heads that are attached, for which there is no consensus. Surprisingly, the stiffness of the myosin head from the edible frog, Rana esculenta, determined in the same manner, is only 60% of that in Rana temporaria. In our view it is unlikely that the value of such a crucial parameter could differ so substantially between two frog species. Since the means of the myosin head stiffness in these two species are not significantly different, we suggest that the best estimate of the stiffness of the myosin heads for frog muscle is the average of these data, a value similar to that for rabbit muscle. This would allow both frog and rabbit muscles to operate the same low-cooperativity mechanism for the crossbridge cycle with only one or two tension-generating steps. We review evidence that much of the compliance of the myosin head is located in the pliant region where the lever arm emerges from the converter and propose that tension generation ("tensing") caused by the rotation and movement of the converter is a separate event from the passive swinging of the lever arm in its working stroke in which the strain energy stored in the pliant region is used to do work.

A fish bradykinin (Arg 0, Trp 5, Leu 8-bradykinin) from the defensive skin secretion of the European edible frog, Pelophylax kl. esculentus: Structural characterization; molecular cloning of skin kininogen cDNA and pharmacological effects on mammalian smooth muscle

Extensive studies on bradykinin-related peptides (BRPs) generated from plasma kininogens in representative species of various vertebrate taxa, have confirmed that many amphibian skin BRPs reflect those present in putative vertebrate predators. For example, the (Val 1, Thr 6)-bradykinin, present in the defensive skin secretions of many ranids and phyllomedusines, can be generated from plasma kininogens in colubrid snakes—common predators of these frogs. Here, we report the presence of (Arg 0, Trp 5, Leu 8)-bradykinin in the skin secretion of the European edible frog, Pelophylax kl . esculentus, and have found it to be encoded in single copy by a kininogen with an open-reading frame of 68 amino acid residues. This peptide is the archetypal bony fish bradykinin that has been generated from plasma kininogens of the bowfin ( Amia calva), the long-nosed gar ( Lepisosteus oseus) and the rainbow trout ( Onchorhynchus mykiss). More recently, this peptide has been shown to be encoded within cloned kininogens of the Atlantic cod ( Gadus morhua) spotted wolf-fish ( Anarichas minor), zebrafish ( Danio rerio), pufferfish ( Tetraodon nigroviridis) and Northern pike ( Esox lucius). The latter species is regarded as a major predator of P. kl. esculentus. Synthetic (Arg 0, Trp 5, Leu 8)-bradykinin was previously reported as having multiphasic effects on arterial blood pressure in conscious trout and here we have demonstrated that it can antagonize the relaxation in rat arterial smooth muscle induced by canonical mammalian bradykinin. The discovery of (Arg 0, Trp 5, Leu 8)-bradykinin in the defensive skin secretion of this amphibian completes the spectrum of vertebrate taxon-specific BRPs identified from this source.

A novel and potent trypsin inhibitor peptide, AC-17, from the skin secretion of the edible frog, Rana esculenta

A novel and potent trypsin inhibitor peptide, AC-17, from the skin secretion of the edible frog, Rana esculenta