On the role of TFEC in reptilian coloration

Reptilian species, particularly snakes and lizards, are emerging models of animal coloration. Here, I focus on the role of the TFEC transcription factor in snake and lizard coloration based on a study on wild-type and piebald ball pythons. Genomic mapping previously identified a TFEC mutation linked to the piebald ball python phenotype. The association of TFEC with skin coloration was further supported by gene-editing experiments in the brown anole lizard. However, novel histological analyses presented here reveal discrepancies between the ball python and the anole TFEC mutants phenotype, cautioning against broad generalizations. Indeed, both wild-type and piebald ball pythons completely lack iridophores, whereas the TFEC anole lizard mutants lose their iridophores compared to the wild-type anole. Based on these findings, I discuss the potential role of the MiT/TFE family in skin pigmentation across vertebrate lineages and advocate the need for developmental analyses and additional gene-editing experiments to explore the reptilian coloration diversity.

The Role of Host Species in Experimental Ferlavirus Infection: Comparison of a Single Strain in Ball Pythons (Python regius) and Corn Snakes (Pantherophis guttatus)

Ferlaviruses are a cause of respiratory disease in snakes. Four genogroups (A, B, C, and tortoise) have been described. Disease development is believed to depend on virus, host, and environment-specific factors. There is evidence of transmission of individual strains between genera and families of reptiles. A genogroup B virus previously used in a transmission study with corn snakes (Pantherophis guttatus) was applied intratracheally in ball pythons (Python regius) using the same protocol as for the corn snakes. Ball pythons became infected, with initial mild clinical signs noted four days post infection (p.i.), and the virus was detected first in the lungs on day 4 and spread to the intestine, pancreas, kidney and brain. Hematology showed an increase in circulating lymphocytes which peaked on day 28 p.i. Antibodies were detected beginning on day 16 and increased steadily to the end of the study. In comparison to corn snakes, ball pythons exhibited milder clinical signs and pathological changes, faster development of and higher antibody titers, and a hematological reaction dominated by lymphocytosis in contrast to heterophilia in corn snakes. These differences in host reaction to infection are important to understand ferlavirus epidemiology as well as for clinical medicine and diagnostic testing.

Piebaldism and chromatophore development in reptiles are linked to the tfec gene

Reptiles display great diversity in color and pattern, yet much of what we know about vertebrate coloration comes from classic model species such as the mouse and zebrafish.1,2,3,4 Captive-bred ball pythons (Python regius) exhibit a remarkable degree of color and pattern variation. Despite the wide range of Mendelian color phenotypes available in the pet trade, ball pythons remain an overlooked species in pigmentation research. Here, we investigate the genetic basis of the recessive piebald phenotype, a pattern defect characterized by patches of unpigmented skin (leucoderma). We performed whole-genome sequencing and used a case-control approach to discover a nonsense mutation in the gene encoding the transcription factor tfec, implicating this gene in the leucodermic patches in ball pythons. We functionally validated tfec in a lizard model (Anolis sagrei) using the gene editing CRISPR/Cas9 system and TEM imaging of skin. Our findings show that reading frame mutations in tfec affect coloration and lead to a loss of iridophores in Anolis, indicating that tfec is required for chromatophore development. This study highlights the value of captive-bred ball pythons as a model species for accelerating discoveries on the genetic basis of vertebrate coloration.

Oral Abscess Caused by Chryseobacterium indologenes in Ball Python (Python regius); A Case Report

Chryseobacterium indologenes is an opportunistic pathogen isolated from human infections and, rarely, from some aquatic animals. A 3-year-old male ball python (Python regius) was admitted to the veterinary clinic by a pet owner because of acute respiratory and swallowing failure. During physical examinations, oral secretions and abscesses were observed in the mouth cavity and throat of the animal. After microbiological analysis including isolation, identification, and 16s rRNA sequencing, C. indologenes was detected as the main cause of the oral abscess in this case. Phylogenetic relatedness analysis showed a close relationship between this isolate and other strains isolated from human infections. Antimicrobial susceptibility testing revealed that the isolate was multi-drug resistant. However, it was very sensitive to minocycline, ceftazidime, and tetracycline. The patient was treated by antibiotic therapy and completely recovered after two weeks. To the best of our knowledge, this is the first incidence of C. indologenes in an oral abscess in a ball python. As a result we would consider this organism as an opportunistic animal pathogen with zoonotic potentiality.

Using Google Trends to Determine Current, Past, and Future Trends in the Reptile Pet Trade

Reptiles are one of the most popular exotic pets in the world, with over a third of all described species currently being traded. However, the most commonly available reptiles are typically non-threatened, captive-bred, and/or domestically obtained, which means they are also largely unregulated and unmonitored, resulting in a large portion of the reptile pet trade remaining unknown. In this study, the past, current, and future trends of the most popular reptiles in the pet trade were examined. Google Trends was used to determine the global popularity of the most popular pets from 2004 to 2020 and compared to the results from an online survey sent to individuals involved in the reptile trade. The most popular pets from the previous five years were also compared globally across regions and countries. The results determined that the most popular reptile species during the last decade is by far bearded dragons, followed by ball pythons and leopard geckos. Although the survey results were similar when asked what the top reptiles were, most respondents named ball pythons as the most popular reptile. However, when asked what reptiles had lost the most popularity during the previous decade, the survey respondents named green iguanas, Burmese pythons, chameleons, red-eared sliders, and green anoles, concurring with what was found with Google Trends. The reptiles thought to be more popular in the upcoming decade by the survey participants were blue-tongued skinks, tegus, uromastyx, crested geckos, and ball pythons-most of which did indeed show an increase in popularity during the last decade, as indicated with Google Trends. The results from Google Trends demonstrated that ball pythons and crested geckos have increased their popularity more than any other reptile in the last two decades. Reptile popularity also differed between countries, with bearded dragons the most popular reptile in Australia, Western Europe, the U.S., and Canada. Leopard geckos were the most popular reptile in Italy and Turkey, and ball pythons were the reptile of choice in Mexico, Indonesia, and India. The general finding of this study is that the reptiles declining in popularity were mostly wild-caught or restricted due to regulations, while current and future species were captive-bred and available in many varieties or morphs. The most popular species were also docile, medium-sized, and easy to handle, with relatively simple care requirements. This study demonstrates that Google Trends can be a useful tool for determining relative popularity among reptiles, or any other pet group, with results closely mirroring those obtained through direct surveying of people involved in the pet trade. However, unlike surveys, this analysis is quick, quantifiable, and can show what is popular and in-demand not only at the global level but at much finer scales. Thus, Google Trends can be a valuable tool in many research applications, especially in topics that may otherwise be difficult to monitor and quantify.

Pharmacokinetics of midazolam and its major metabolite 1-hydroxymidazolam in the ball python (Python regius) after intracardiac and intramuscular administrations

Midazolam is a benzodiazepine with sedative, muscle relaxant, anxiolytic, and anticonvulsant effects. Twelve ball pythons (Python regius) were used in a parallel study evaluating the pharmacokinetics of 1 mg/kg midazolam following a single intracardiac (IC) or intramuscular (IM) administration. Blood was collected from a central venous catheter placed 7 days prior, or by cardiocentesis, at 15 time points starting just prior to and up to 72 hr after drug administration. Plasma concentrations of midazolam and 1-hydroxymidazolam were determined by the use of high-performance liquid chromatography tandem-mass spectrometry and pharmacokinetic parameters were estimated using noncompartmental analysis. The mean ± SD terminal half-lives of IC and IM midazolam were 12.04 ± 3.25 hr and 16.54 ± 7.10 hr, respectively. The area under the concentration-time curve extrapolated to infinity, clearance, and apparent volume of distribution in steady-state of IC midazolam were 19,112.3 ± 3,095.9 ng*hr/ml, 0.053 ± 0.008 L hr^-1  kg^-1 , and 0.865 ± 0.289 L/kg, respectively. The bioavailability of IM midazolam was estimated at 89%. Maximum plasma concentrations following an IM administration were reached 2.33 ± 0.98 hr and 24.00 ± 14.12 hr postinjection for midazolam and 1-hydroxymidazolam, respectively, and 22.33 ± 20.26 hr postinjection for 1-hydroxymidazolam following IC administration.

Snake spectacle vessel permeability to sodium fluorescein

OBJECTIVE

Assess vascular permeability of the snake spectacle to sodium fluorescein during resting and shedding phases of the ecdysis cycle.

ANIMAL STUDIED

Ball python (Python regius).

PROCEDURES

The snake was anesthetized, and spectral domain optic coherence tomography was performed prior to angiographic procedures. An electronically controlled digital single-lens reflex camera with a dual-head flash equipped with filters suitable for fluorescein angiography was used to make images. Sodium fluorescein (10%) solution was administered by intracardiac injection. Angiographic images were made as fluorescein traversed the vasculature of the iris and spectacle. Individually acquired photographic frames were assessed and sequenced into pseudovideo image streams for further evaluation CONCLUSIONS: Fluorescein angiograms of the snake spectacle were readily obtained. Vascular permeability varied with the phase of ecdysis. Copious leakage of fluorescein occurred during the shedding phase. This angiographic method may provide diverse opportunities to investigate vascular aspects of snake spectacle ecdysis, dysecdysis, and the integument in general.