Discovery of a Novel Accessory Structure of the Pitviper Infrared Receptor Organ (Serpentes: Viperidae)

The facial pits of rattlesnakes, copperheads, lanceheads, bushmasters and other American and Asian pitvipers (Crotalinae) are highly innervated and densely vascularized infrared (IR) receptor organs. For over a century, studies have focused on a small sample of model species from North America and Asia. Based on an expanded survey of Central and South American crotalines, we report a conspicuous accessory structure composed of well-defined papillae that project from the anterior orbital adnexa. The papillae are continuous with the inner chamber of the IR receptor organ and our histological and ultrastructural data suggest that they possess a well-developed nervous network and extensive vascularization; however, they lack the characteristic IR-sensitive terminal nerve masses found in the IR-receptive pit membrane. The function of the IR receptor organ papillae is unknown.Conselho Nacional de Desenvolvimento Científico (Proc. 307029/2009-3, 306529/2010-6, 307001/2011-3)Instituto Nacional de Ciência e Tecnologia em ToxinologiaFundação de Amparo à Pesquisa do Estado de São Paulo (Proc. 2012/10000-5

Morphological Evidence for an Oral Venom System in Caecilian Amphibians

Amphibians are known for their skin rich in glands containing toxins employed in passive chemical defense against predators, different from, for example, snakes that have active chemical defense, injecting their venom into the prey. Caecilians (Amphibia, Gymnophiona) are snake-shaped animals with fossorial habits, considered one of the least known vertebrate groups. We show here that amphibian caecilians, including species from the basal groups, besides having cutaneous poisonous glands as other amphibians do, possess specific glands at the base of the teeth that produce enzymes commonly found in venoms. Our analysis of the origin of these glands shows that they originate from the same tissue that gives rise to teeth, similar to the venom glands in reptiles. We speculate that caecilians might have independently developed mechanisms of production and injection of toxins early in their evolutionary history

Variations in Tetrodotoxin Levels in Populations of Taricha granulosa are Expressed in the Morphology of Their Cutaneous Glands

Tetrodotoxin (TTX), one of the most toxic substances in nature, is present in bacteria, invertebrates, fishes, and amphibians. Marine organisms seem to bioaccumulate TTX from their food or acquire it from symbiotic bacteria, but its origin in amphibians is unclear. Taricha granulosa can exhibit high TTX levels, presumably concentrated in skin poison glands, acting as an agent of selection upon predatory garter snakes (Thamnophis). This co-evolutionary arms race induces variation in T. granulosa TTX levels, from very high to undetectable. Using morphology and biochemistry, we investigated differences in toxin localization and quality between two populations at the extremes of toxicity. TTX concentration within poison glands is related to the volume of a single cell type in which TTX occurs exclusively in distinctive secretory granules, suggesting a relationship between granule structure and chemical composition. TTX was detected in mucous glands in both populations, contradicting the general understanding that these glands do not secrete defensive chemicals and expanding currently held interpretations of amphibian skin gland functionality. Skin secretions of the two populations differed in low-mass molecules and proteins. Our results demonstrate that interpopulation variation in TTX levels is related to poison gland morphology

Skin Gland Concentrations Adapted to Different Evolutionary Pressures in The Head and Posterior Regions of The Caecilian Siphonops Annulatus

Amphibian skin is rich in mucous glands and poison glands, secreting substances important for gas exchange and playing a fundamental role in chemical defense against predators and microorganisms. In the caecilian Siphonops annulatus (Mikan, 1920) we observed a concentration of enlarged mucous glands in the head region. In the posterior region of the body a similar concentration is made up of enlarged poison glands. These accumulations of glands structurally resemble the macroglands previously reported in anurans and salamanders. The skin glands in these regions are each surrounded by collagen walls forming a honeycomb-like structure. The collagen network in the head region firmly attaches to tiny pits in the bones of the skull. The two extremities of the body produce different secretions, containing exclusive molecules. Considering the fossorial lifestyle of caecilians, it seems evident that the secretions of the head and caudal region serve different functions. The anterior macrogland of mucous glands, rich in mucous/lipid secretion, in conjunction with the funnel-shaped head, may act to lubricate the body and penetrate the soil, thus facilitating locomotion underground. The blunt posterior end bearing an internalized macrogland of poison glands in the dermis may act in chemical defense and/or by blocking invasion of tunnels

Pollinator-flower interactions in gardens during the covid 19 pandemic lockdown of 2020

During the main COVID-19 global pandemic lockdown period of 2020 an impromptu set of pollination ecologists came together via social media and personal contacts to carry out standardised surveys of the flower visits and plants in gardens. The surveys involved 67 rural, suburban and urban gardens, of various sizes, ranging from 61.18° North in Norway to 37.96° South in Australia, resulting in a data set of 25,174 rows, with each row being a unique interaction record for that date/site/plant species, and comprising almost 47,000 visits to flowers, as well as records of flowers that were not visited by pollinators, for over 1,000 species and varieties belonging to more than 460 genera and 96 plant families. The more than 650 species of flower visitors belong to 12 orders of invertebrates and four of vertebrates. In this first publication from the project, we present a brief description of the data and make it freely available for any researchers to use in the future, the only restriction being that they cite this paper in the first instance. The data generated from these global surveys will provide scientific evidence to help us understand the role that private gardens (in urban, rural and suburban areas) can play in conserving insect pollinators and identify management actions to enhance their potential

A new species of Microcaecilia Taylor, 1968 (Amphibia: Gymnophiona: Siphonopidae) from Amazonian Brazil

Wilkinson, Mark, Antoniazzi, Marta Maria, Jared, Carlos (2015): A new species of Microcaecilia Taylor, 1968 (Amphibia: Gymnophiona: Siphonopidae) from Amazonian Brazil. Zootaxa 3905 (3): 425-431, DOI: 10.11646/zootaxa.3905.3.

FIGURE 2 in A new species of Microcaecilia Taylor, 1968 (Amphibia: Gymnophiona: Siphonopidae) from Amazonian Brazil

FIGURE 2. Microcaecilia butantan sp. nov. (A) Specimen in life dorsal view. Bar = 5 mm. (B) Specimen in life ventral view. Bar = 5 mm. (C) Habitat at type locality

Cathepsin B/X is secreted by Echinometra lucunter sea urchin spines, a structure rich in granular cells and toxins

Background Echinometra lucunter is a common American sea urchin responsible for the majority of the marine accidents in Brazil. Although not lethal, these accidents are reported to be extremely painful. Recently, our group described the presence of toxins in its spines that contribute to the pathological reactions. Additionally, we have observed that the E. lucunter spines can regenerate when broken. In the present work we evaluated the enzymatic activities of sea urchin spine extracts in order to identify an enzyme that could contribute not only to the toxicity, but also participate in the spine growth and regeneration. Results The spine aqueous extract was tested for peptidase activity, with synthetic substrates, in the presence and absence of inhibitors and activators. For proper enzyme classification, the FRET-substrate cleavage pattern, pH-dependency activity and Western-blot analyses were performed. The spine extract was able to cleave Z-R-MCA and Abz-GIVRAK(Dnp)-OH following pre-incubation with DTT, and was inhibited by E-64. Furthermore, the double-peaked pH curve (5 and 7) and the cleavage site proportion (4:6, R|A:A|K) indicate the presence of both mono and dicarboxypeptidase activities. Moreover, in Western-blot analysis, the spine extract was positive for anti-cathepsin B antibody. Conclusions E. lucunter spines extracts presented a cysteine peptidase activity that was identified as cathepsin B/X that would participate in the remodeling and growth processes of the spine, as well as in the inflammatory response to the accident

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Abstract. Amphibian defence mechanisms commonly rely on cutaneous toxins produced in either isolated or clustered glands, such as toad parotoid macroglands. In contrast to the passive mechanism of poison liberation in other amphibians, we discovered that the Amazonian toad Rhaebo guttatus is unique because it can voluntarily squirt jets of poison from its parotoids

Melanomacrophage functions in the liver of the caecilian Siphonops annulatus

Melanomacrophages are phagocytes that synthesize melanin. They are found in the liver and spleen of ectothermic vertebrates, and in the kidney of fish. In agnathan and elasmobranch fish, melanomacrophages are seen as isolated cells, and forming clusters in all the other vertebrates. The natural phagocytic activity of melanomacrophages is poorly characterized, as most of the research works have focused on induced phagocytic activity only. Furthermore, little is known about amphibian melanomacrophages, mainly about those in caecilians - wormlike amphibians in the order of Gymnophiona, which is the least known group of terrestrial vertebrates. The present research work aimed at the structure and function of hepatic melanomacrophages of Siphonops annulatus, a species largely found in South America. We identified the role of these cells in the control of circulating basophils (pro-melanogenic cells), in the turnover of liver collagen stroma and in the hemocatheresis, interrelated physiological mechanisms.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - CAPESConselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNPqUniv Fed Sao Paulo, Escola Paulista Med, Dept Morphol & Genet, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Neurol & Neurosurg, Sao Paulo, BrazilInst Butantan, Cell Biol Lab, Sao Paulo, BrazilUniv Surrey, Sch Vet Med, Fac Hlth & Med Sci, Guildford, Surrey, EnglandUniv Fed Sao Paulo, Escola Paulista Med, Dept Morphol & Genet, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Neurol & Neurosurg, Sao Paulo, BrazilWeb of Scienc