scholarly journals Evidence for Snake Venom Plasticity in a Long-Term Study with Individual Captive Bothrops atrox

Toxins ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 294 ◽  
Author(s):  
Diana R. Amazonas ◽  
Luciana A. Freitas-de-Sousa ◽  
Daniele P. Orefice ◽  
Leijiane F. de Sousa ◽  
Melissa G. Martinez ◽  
...  
Keyword(s):  
Snake Venom ◽  
Individual Variability ◽  
Long Term Study ◽  
Venom Composition ◽  
Core Function ◽  
In Captivity ◽  
Functional Consequences ◽  
Bothrops Atrox ◽  
Diet Type

Variability in snake venom composition has been frequently reported and correlated to the adaptability of snakes to environmental conditions. Previous studies report plasticity for the venom phenotype. However, these observations are not conclusive, as the results were based on pooled venoms, which present high individual variability. Here we tested the hypothesis of plasticity by influence of confinement and single diet type in the venom composition of 13 adult specimens of Bothrops atrox snakes, maintained under captivity for more than three years. Individual variability in venom composition was observed in samples extracted just after the capture of the snakes. However, composition was conserved in venoms periodically extracted from nine specimens, which presented low variability restricted to the less abundant components. In a second group, composed of four snakes, drastic changes were observed in the venom samples extracted at different periods, mostly related to snake venom metalloproteinases (SVMPs), the core function toxins of B. atrox venom, which occurred approximately between 400 and 500 days in captivity. These data show plasticity in the venom phenotype during the lifetime of adult snakes maintained under captive conditions. Causes or functional consequences involved in the phenotype modification require further investigations.

scholarly journals The use of visible implant elastomer to permanently identify caecilians (Amphibia: Gymnophiona)

2019 ◽  
pp. 18-22
Author(s):  
Benjamin Tapley
Keyword(s):  
Optimal Management ◽  
Term Study ◽  
Long Term Study ◽  
In Captivity ◽  
Marking Technique

Identifying individual animals is important for studying populations and for the optimal management of individual animals in captivity. In the absence of natural markings that discriminate individuals, such identification may require animals to be marked by researchers. Amphibians are challenging subjects to mark due to their small size and sensitive, permeable and frequently shed skin. Visible Implant Elastomer (VIE) has been widely used to mark amphibians, but no long-term study has validated this technique in caecilian amphibians. We anaesthetised and attempted to VIE mark seven Herpele squalostoma and one Microcaecilia unicolor held at ZSL London Zoo. No specimens suffered ill effects of anaesthesia or VIE injection, but mean persistence of marks was 191 days in H. squalostoma suggesting that this marking technique is not suitable for identifying individuals of this species in the long-term. We were unable to inject VIE into the M. unicolor and/or the elastomer was not visible through the darkly pigmented skin. Further research is required to develop methods for long-term marking of a diversity of caecilians.

scholarly journals Individual Variability in Bothrops atrox Snakes Collected from Different Habitats in the Brazilian Amazon: New Findings on Venom Composition and Functionality

Toxins ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 814
Author(s):  
Leijane F. Sousa ◽  
Matthew L. Holding ◽  
Tiago H. M. Del-Rei ◽  
Marisa M. T. Rocha ◽  
Rosa H. V. Mourão ◽  
...  
Keyword(s):  
Brazilian Amazon ◽  
Individual Variability ◽  
Protein Isoforms ◽  
Differential Distribution ◽  
Functional Assays ◽  
Venom Composition ◽  
New Findings ◽  
Degraded Area ◽  
The Individual ◽  
Bothrops Atrox

Differences in snake venom composition occur across all taxonomic levels and it has been argued that this variation represents an adaptation that has evolved to facilitate the capture and digestion of prey and evasion of predators. Bothrops atrox is a terrestrial pitviper that is distributed across the Amazon region, where it occupies different habitats. Using statistical analyses and functional assays that incorporate individual variation, we analyzed the individual venom variability in B. atrox snakes from four different habitats (forest, pasture, degraded area, and floodplain) in and around the Amazon River in Brazil. We observed venom differentiation between spatially distinct B. atrox individuals from the different habitats, with venom variation due to both common (high abundance) and rare (low abundance) proteins. Moreover, differences in the composition of the venoms resulted in individual variability in functionality and heterogeneity in the lethality to mammals and birds, particularly among the floodplain snakes. Taken together, the data obtained from individual venoms of B. atrox snakes, captured in different habitats from the Brazilian Amazon, support the hypothesis that the differential distribution of protein isoforms results in functional distinctiveness and the ability of snakes with different venoms to have variable toxic effects on different prey.

Quinapril for Sclerosis Failed in Long-Term Study

2007 ◽  
Vol 38 (6) ◽  
pp. 14
Author(s):  
DAMIAN MCNAMARA
Keyword(s):  
Term Study ◽  
Long Term Study

Theoretical and Methodological Problems of a 10-Year Follow-Up Program Evaluation Study

2002 ◽  
Vol 18 (3) ◽  
pp. 229-241 ◽  
Author(s):  
Kurt A. Heller ◽  
Ralph Reimann
Keyword(s):  
Program Evaluation ◽  
Evaluation Studies ◽  
Evaluation Study ◽  
Control Groups ◽  
Cross Sectional ◽  
Long Term Study ◽  
Partial Inclusion ◽  
Methodological Problems

Summary In this paper, conceptual and methodological problems of school program evaluation are discussed. The data were collected in conjunction with a 10 year cross-sectional/longitudinal investigation with partial inclusion of control groups. The experiences and conclusions resulting from this long-term study are revealing not only from the vantage point of the scientific evaluation of new scholastic models, but are also valuable for program evaluation studies in general, particularly in the field of gifted education.

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