Python Molurus Research Articles

The effect of acute mental stress on the exchange of monoamines in the mesocortical and nigrostriatal systems of the rat brain

Background. Мesocortical and nigrostriatal dopaminergic systems are highly sensitive to stressful events. One of the most adequate models of acute psychogenic stress in animals is the death of a partner upon presentation of a predator.
 Aim. To study the content of dopamine (DA), serotonin and their metabolites: dioxyphenylacetic (DOPAC), homovanillic and 5-hydroxyindoleacetic (5-HIAA) acids in the prefrontal cortex, striatum, and ventral tegmental area in rats on days 3, 7, and 14 after the acute psychogenic stress of the death of a partner upon presentation of a predator.
 Materials and methods. 28 male Wistar rats were studied. Acute single psychotraumatic situation was used. A group of rats was placed in a tiger python terrarium. One animal died as a result of its nutritional needs, the rest of the rats experienced the death of a partner. The content of monoamines in the brain structures was carried out by high performance liquid chromatography with electrochemical detection.
 Results. Changes in the content of monoamines in the prefrontal cortex, striatum, and ventral tegmental area were found on the 7 and 14 days after the presentation of the predator. In the ventral tegmental area on the 7 day, there was an increase in the DOPAC/DA ratio and an increase in the serotonin metabolite 5-HIAA, which reflects an increase in the activity of dopamine and serotonin. In the prefrontal cortex on the 14 day, the DOPAС content and the DOPAС/DA index decreased. The 5-HIAA content in the prefrontal cortex and the 5-HIAA/5-HT value also significantly decreased.
 Conclusions. Changes in the metabolism of monoamines after presentation of a predator develop gradually: increase of the dopamine and serotonin activity in the ventral tegmental area was noted on the 7 day after presentation of the predator, decrease in their activity in the striatum and prefrontal cortex only on the 14 day, reflecting the development of depressive states and post-traumatic stress disorder.

Burmese pythons exhibit a transient adaptation to nutrient overload that prevents liver damage.

As an opportunistic predator, the Burmese python (Python molurus bivittatus) consumes large and infrequent meals, fasting for up to a year. Upon consuming a large meal, the Burmese python exhibits extreme metabolic responses. To define the pathways that regulate these postprandial metabolic responses, we performed a comprehensive profile of plasma metabolites throughout the digestive process. Following ingestion of a meal equivalent to 25% of its body mass, plasma lipoproteins and metabolites, such as chylomicra and bile acids, reach levels observed only in mammalian models of extreme dyslipidemia. Here, we provide evidence for an adaptive response to postprandial nutrient overload by the python liver, a critical site of metabolic homeostasis. The python liver undergoes a substantial increase in mass through proliferative processes, exhibits hepatic steatosis, hyperlipidemia-induced insulin resistance indicated by PEPCK activation and pAKT deactivation, and de novo fatty acid synthesis via FASN activation. This postprandial state is completely reversible. We posit that Burmese pythons evade the permanent hepatic damage associated with these metabolic states in mammals using evolved protective measures to inactivate these pathways. These include a transient activation of hepatic nuclear receptors induced by fatty acids and bile acids, including PPAR and FXR, respectively. The stress-induced p38 MAPK pathway is also transiently activated during the early stages of digestion. Taken together, these data identify a reversible metabolic response to hyperlipidemia by the python liver, only achieved in mammals by pharmacologic intervention. The factors involved in these processes may be relevant to or leveraged for remediating human hepatic pathology.

The Indian Rock Python (Python molurus) in the Thol Lake Bird Sanctuary, Gujarat, India: Evidence of Reproduction and a Roadkill

The Indian Rock Python (Python molurus) in the Thol Lake Bird Sanctuary, Gujarat, India: Evidence of Reproduction and a Roadkill

Surgical management of lacerated wounds and rehabilitation of a rescued Indian rock python (Python molurus): A case report

An injured Indian Rock Python, rescued by the Forest Department of Kerala, was presented to the University Veterinary Hospital, Kokkalai, Thrissur. The lacerated wounds were cleaned and sutured under local anaesthesia. The post-operative care was given in the rescue centre of the Forest Department and the snake was released into the wild on complete wound healing.

The mitochondrial genome sequence analysis of Ophidascaris baylisi from the Burmese python (Python molurus bivittatus).

Ophidascaris species are parasitic roundworms that inhabit the python gut, resulting in severe granulomatous lesions or even death. However, the classification and nomenclature of these roundworms are still controversial. Our study aims to identify a snake roundworm from the Burmese python (Python molurus bivittatus) and analyze the mitochondrial genome. We identified this roundworm as Ophidascaris baylisi based on the morphology and cytochrome c oxidase subunit I (cox1) sequence. Ophidascaris baylisi complete mitochondrial genome was 14,784bp in length, consisting of two non-coding regions and 36 mitochondrial genes (12 protein-coding genes, 22 tRNA genes, and two rRNA genes). The protein-coding genes used TTG, ATG, ATT, or TTA as start codons and TAG, TAA, or T as stop codons. All tRNA genes showed a TV-loop structure, except trnS1AGN and trnS2UCN revealed a D-loop structure. The mitochondrial large ribosomal subunit 16S (rrnL) and small ribosomal subunit 12S (rrnS) were 956bp and 700bp long, respectively. Phylogenetic analysis based on O. baylisi mitochondrial protein-coding genes demonstrated that O. baylisi clustered with the family Ascarididae members and was most closely related to Ophidascaris wangi. These results may enhance the nematode mitochondrial genome database and provide valuable molecular markers for further research on the taxonomy, phylogeny, and genetic relationships of Ophidascaris nematodes.

Native mammals lack resilience to invasive generalist predator

Invasive predators have caused catastrophic declines in native wildlife across the globe. Though research has focused on the initial establishment, rapid growth, and spread of invasive predators, our understanding of prey resilience to established invasive predators remains limited. As a direct result of invasive Burmese pythons (Python molurus bivittatus), medium- to large-bodied native mammals decreased drastically across much of southern Florida as early as 2003. By 2014, most of these mammal species were exceedingly rare within the core invasion area, while pythons expanded outward to newly invaded areas. We used python observations to delineate the core python invasion area from the more recently invaded invasion front, and we compared changes in mammal occurrence from 2014 to 2019 between these two areas. We surveyed mammal communities using camera traps and scat surveys and used these observations to quantify the changes in occurrence among mammal species. As expected, occurrence of medium- and large-bodied mammals declined within the invasion front. However, contrary to our expectation, we observed little evidence of resilience among mammals within the invasion core. Of the 15 species detected in 2019, invasive black rats were the only species to increase in occurrence within the invasion core. Additionally, we observed declines in occurrence among native rodents within the invasion core, which were previously thought to be resistant to the effects of pythons. The continued presence of invasive pythons appears to be shifting the diverse mammal communities of southern Florida to one primarily composed of invasive species.

Reactive changes of gastric mucosa and reduction of desacyl grelin in rat brain due to psychoemotional stress

BACKGROUND: The work is devoted to the analysis of the elements the reactivity of grelin system in the model of psychogenic stress. In recent years, it has been shown that the ghrelin brain system is not limited only to the regulation of energy balance and eating behavior. Along with other peptide regulatory systems, it plays an important role in the mechanisms of stress, reward and addiction. Therefore, the elements of this system should be considered primarily as molecular targets of pharmacological action in order to correct the states of addiction and post-stress disorders.
 MATERIALS AND METHODS: To produce psychoemotional stress, we used an acute single traumatic situation in male Wistar rats. The animals were placed in the tiger python, one animal died as a result of its nutritional needs, the rest of the rats experienced the death of a partner. One week after exposure to python, the animals were decapitated, and the brain structures were isolated. Aliquots of the brain structures suspensions were examined for the content of desacyl ghrelin (DAG) using a highly sensitive enzyme-linked immunosorbent assay (ELISA). In another group, rats were decapitated on the 4th day after exposure to python, stomachs were removed, which were fixed in 10% formalin solution. In horizontal paraffin sections of the gastric mucosa, after staining with hematoxylin and eosin, the heights of superficial and dimple mucous cells, the height of the dimple stroma, the area of superficial, dimple mucocytes and stroma of the dimples, and the number of dead mucocytes were calculated. To clarify the differentiation of epithelial cells, they were stained with alcian blue
 RESULTS: DAG was detected in all studied brain structures: amygdala, hippocampus, and hypothalamus. The highest concentration of DAG was noted in the hypothalamus (p 0.05), which may serve as an indirect confirmation of the data on the presence of ghrelin-containing neurons in the nuclei of the hypothalamus. After exposure to stress, a sharp decrease in the level of DAG was observed in all studied brain structures (812 times, p 0.01): amygdala, hippocampus, and hypothalamus. It has been established that the experience of the stress of the death of a partner is expressed by erosive inflammation of the gastric mucosa, the death of many mucous cells, and an increase in mucus production in viable epithelial cells.
 CONCLUSION: Psychoemotional stress completely suppresses the content of desacyl ghrelin of the brain in rats, which may be based on both a disturbance of the central mechanisms of limbic regulation and a violation of peripheral mechanisms, in particular, reactive changes in the gastric mucosa.

Human–wildlife interactions and people’s attitudes towards conservation: a case study from Central Kerala, India

This paper studies the human–wildlife interaction in Central Kerala, India, and attempts to understand local people’s attitude toward wildlife and conservation. Data were collected from April 2009 to March 2014. A structured questionnaire survey was carried out among people living in the fringe areas of the forest (n = 210). Self–reported household crop loss was modelled as a function of agricultural, demographic and environmental factors. Wild pig (Sus scrofa) (57.1 %) was the main crop foraging species, followed by Asian elephant (Elephas maximus) (12.9 %). It was reported that 36 % of farmers’ annual income was lost due to crop foraging by wild animals. Leopard (Panthera pardus) (69.76 %), Indian rock python (Python molurus) (13.95 %), dhole (Cuon alpinus) (9.3 %) and stray dogs (6.97 %) were responsible for the attacks on livestock. The factors that influenced crop loss according to the farmers were the extent of agriculture land that they owned (coefficient = 0.968), the distance to reserve forest from crop fields (–0.009), and age of respondents (0.78). Due to people’s awareness concerning the importance of wildlife, reports on human–wildlife interaction in the newspapers and strict enforcement of wildlife laws, people’s attitude towards conservation of wildlife was good, and they were not taking any negative precautions against wild animals.

1-desamino-8-D-arginin-vasopressin, DDAVP, increases the content of brain-derived neurotrophic factor (BDNF) in blood plasma of rats in model of post-traumatic stress disorder

Objective. We aimed to analyze the effect of an agonist of vasopressin type 2 receptors, 1-desamino-8-D-arginine-vasopressin, DDAVP, on the content of the brain neurotrophic factor, BDNF, in the hippocampus and blood plasma of rats exposed to vital stress.
 Material and methods. The study carried out on female Wistar rats divided into 4 groups: first group included control animals, 2 those who received DDAVP intranasally in small doses (once 2 ∙ 109 g, course 20 ∙ 109 g), 3 those who exposed to the stress of a threat to life caused by the experience of the death of a partner from the actions of a tiger python, 4 those who exposed to stress and received DDAVP. BDNF concentration in samples was measured by immunohistochemical method.
 Results. An increase in the content of BDNF in blood plasma in rats exposed to acute psychogenic stress and received DDAVP therapy was revealed on the tenth day after stress. There was no effect of stress, DDAVP, or their combined effect on the BDNF content in the homogenate of hippocampal tissues.
 Conclusion. The results of this pilot study indicate that DDAVP has a modulatory effect on BDNF metabolism in rats exposed to vital stress. It is assumed that an increase in the level of neurotrophin in the blood of rats reflects the activation of compensatory processes.

Size Matters: First record of minimum male size at maturity and mating of free-ranging, endangered Indian Python Python molurus

Indian python Python molurus (Linnaeus, 1758) is one of the world’s giant snakes with maximum lengths measured six to eight meters. Nevertheless, information on the size at maturity of P. molurus is not available. On February 9, 2019, 12:56 pm, one female and two males were observed during the group mating in Moyar River Valley Landscape, Southern India. We report the first observation on smallest male measuring 198 cm total length, 172 cm snoutvent length and weighing 3.3.kg mated with a radio-tagged larger female. At the end of the mating event everted hemi penis were observed in the male pythons. Our observation on the mating and morphology details of P. molurus gives the first glimpse of juvenile the male maturity that representing the youngest known free-ranging matured male of this poorly studied species in its distribution range.

Indian Rock Pythons (Python molurus) rescued from fishing nets

Indian Rock Pythons (Python molurus) rescued from fishing nets

Bites by snakes of lesser medical importance in a cohort of snakebite patients from rural Sri Lanka

Reporting of snakebite is poor in areas where they are most common. Comparatively, bites by snakes of high medical importance are likely to be documented than snakes of lesser medical importance. This study aims to describe the demographic, epidemiological and, clinical data of patients who were presented during a 49-month study period to a tertiary care center in rural Sri Lanka following authenticated bites by snakes of lesser medical importance. Of the total of 2362 confirmed snakebite patients during the study period, 517 (22%) presented with the offending snake specimen. Of them, 76 (15%) were identified as snakes of lesser medical importance and were included in this study. There were 41 (54%) females. The median ages of females and males were 35 and 43 years respectively. Most patients (86%) were bitten indoors or at home gardens. More than half of them were bitten between 1800 and 0000 h. Most bites (54%) had occurred to the ankle or below. The patients were bitten by 12 species of colubrids, one pythonid (Python molurus), and one viperid (Trimeresurus trigonocephalus). The snake species that caused the most-number of bites was the Trinket snake (Coelognathus helena) (n = 15). Three species of wolf-snakes, Lycodon aulicus, L. anamallensis, and L. striatus were responsible for 12, 11, and 5 bites respectively. Most of the patients (55%) presented to the local hospital and subsequently transferred to the study hospital for further management. None of the patients developed systemic envenoming and five developed mild local pain and swelling. Fifty-six (74%) patients were discharged on the following day, while 18 (24%) were discharged on the third day. There is a need to educate medical personnel working the peripheral hospital on how to identify medically lesser important snakes to avoid unnecessary transfers.

Life-history traits moderate the susceptibility of native mammals to an invasive predator

The invasive Burmese python (Python molurus bivittatus) is causing declines in the numbers and diversity of native mammals in the Greater Everglades Ecosystem (GEE). However, limited evidence suggests that some species may be less susceptible to pythons than others. This difference in susceptibility may be a function of different life-history traits. We analysed incidence data with a multi-species hierarchical occupancy model to evaluate the influence of pythons on native mammals and examine the association between python’s influence on species occurrence and life-history traits. We also used our traits-based model to predict the effects of pythons on occupancy probabilities of five mammalian species of conservation or management concern known to occur in the GEE but not detected in our study. Ten of 18 observed mammals showed significant negative effects from pythons, while one responded positively. We found that three of the six species traits evaluated (mass, fecundity, and habitat breadth) moderated the negative effects of pythons on mammal occurrence and were, thus, useful for predicting species responses. Our results suggest larger, fecund and/or species with wide habitat breadths were less susceptible to increasing relative densities of pythons. Our results also suggest a positive and neutral associations between rodents and relative python density, likely due to wide habitat breadths, high fecundity rates, and the reduction of mammalian predators in areas with higher relative python densities. These trait relationships predicted a negative response of all five unobserved species of management concern included in our analysis. Our study provides a broader understanding of wildlife community vulnerability to invasive predators and demonstrates how trait-based models can be used to elucidate generalizable patterns and generate predictions for rare and/or undetected species.

Response of the Hemostatic System to Acute Vital Stress in Rats

We studied the effect of acute vital stress on the parameters of the hemostasis system in young and old Wistar rats. The psychotraumatic effect was simulated as a situation of emotional stress at the sight of a predator (Indian python) catching and eating a conspecific. In young rats, acute vital stress was followed by inhibition of platelet aggregation, hypercoagulation by the external pathway and final stages of plasma hemostasis, and a decrease in fibrinogen and antithrombin III levels against the background of fibrinolysis activation. In old animals, increased platelet count with reduced aggregation capacity, hypocoagulation by the internal pathway of the plasma hemostasis activation, signs of thrombinemia (a 2-fold increase in soluble fibrin-monomer complexes), an increase in antithrombin III, and inhibition of the fibrinolytic system were observed. Age-related changes in the hemostasis parameters in rats were determined before and after stress exposure.

Investigations into the presence of nidoviruses in pythons

BackgroundPneumonia and stomatitis represent severe and often fatal diseases in different captive snakes. Apart from bacterial infections, paramyxo-, adeno-, reo- and arenaviruses cause these diseases. In 2014, new viruses emerged as the cause of pneumonia in pythons. In a few publications, nidoviruses have been reported in association with pneumonia in ball pythons and a tiger python. The viruses were found using new sequencing methods from the organ tissue of dead animals.MethodsSevere pneumonia and stomatitis resulted in a high mortality rate in a captive breeding collection of green tree pythons. Unbiased deep sequencing lead to the detection of nidoviral sequences. A developed RT-qPCR was used to confirm the metagenome results and to determine the importance of this virus. A total of 1554 different boid snakes, including animals suffering from respiratory diseases as well as healthy controls, were screened for nidoviruses. Furthermore, in addition to two full-length sequences, partial sequences were generated from different snake species.ResultsThe assembled full-length snake nidovirus genomes share only an overall genome sequence identity of less than 66.9% to other published snake nidoviruses and new partial sequences vary between 99.89 and 79.4%. Highest viral loads were detected in lung samples. The snake nidovirus was not only present in diseased animals, but also in snakes showing no typical clinical signs.ConclusionsOur findings further highlight the possible importance of snake nidoviruses in respiratory diseases and proof multiple circulating strains with varying disease potential. Nidovirus detection in clinical healthy individuals might represent testing during the incubation period or reconvalescence. Our investigations show new aspects of nidovirus infections in pythons. Nidoviruses should be included in routine diagnostic workup of diseased reptiles.

Seasonal Variation in Ecdysis Process and Parasitic Prevalence in Indian Rock Python (Python molurus)

Seasonal Variation in Ecdysis Process and Parasitic Prevalence in Indian Rock Python (Python molurus)

Estimating Detection Probability for Burmese Pythons with Few Detections and Zero Recaptures

Detection has been a long-standing challenge to monitoring populations of cryptic herpetofauna, which often have detection probabilities that are closer to zero than to one. Burmese Pythons (Python bivittatus [=Python molurus bivittatus]), a recent invader in the Greater Everglades Ecosystem of Florida, are cryptic snakes that have long periods of inactivity. In addition, management actions such as removal of every python encountered create challenges for estimating population size and quantifying effects of management using traditional statistical approaches. We used Bayesian analysis of data collected from 59 visual surveys (144 person-surveys) covering a total distance of 485.6 km (1,185.1 person-km) and radiotelemetry to estimate detection probability for Burmese Pythons. These estimates can improve interpretation of encounter and removal data. We found that detection probability ranged from 0.0001 to 0.0146 depending on whether effort units accounted for total human effort across multiple surveyors and statistical method used. On the basis of our surveys, detection probabilities for Burmese Pythons are therefore likely <0.05, but factors such as the number of searchers or time of day may improve detection probability. Traditional capture–recapture or visual surveys are, however, unlikely to yield accurate information on Burmese Python population size or trends across time without cost-prohibitive effort. Consequently, novel methods development to monitor or measure Burmese Python populations, including techniques better equipped to handle very low detection, are critically needed for informative and reliable inferences about population size or the management effects of python removal.

A characterization of the electrophysiological properties of the cardiomyocytes from ventricle, atrium and sinus venosus of the snake heart.

A detailed description of the electrophysiological features of cardiomyocytes in the various contractile chambers of the vertebrate heart is essential to understand the evolution of cardiac electrical activity, yet very little is known about reptiles. The present study characterizes major ionic currents (INa, ICaL, IKr, IK1 and IKACh) and action potential (AP) configuration in cardiomyocytes from the ventricle, the right atrium and the sinus venosus (SV) of Burmese pythons (Python molurus) using sharp microelectrode and patch clamp recordings. Special attention was given to SV, since it consists of myocardial cells and appears to contribute to right atrial filling in snakes. We demonstrate that most of the SV in pythons has a stable resting potential of - 82.3 ± 2.6mV (n = 9) and lacks pacemaker activity. AP duration at 50% repolarization was similar in cells from SV and atria (350.2 ± 8.7 and 330.4 ± 17.2ms, respectively; n = 7), but shorter than ventricular APs (557.6 ± 19.2ms, n = 5) at 30°C. The densities of ionic currents, however, differed substantially between atrial and SV cells, where the latter had much lower densities of INa, ICaL and IKr than atrial and ventricular myocytes. IK1 in ventricle was ninefold greater than in atrial cells and 23-fold greater than in myocytes from SV. However, IKACh was absent in ventricular cells, while it was equally large in atrial and SV myocytes. Consistent with this observation, APs of atrium and SV, but not ventricle, were greatly shortened upon addition of acetylcholine (10-6M). Thus, snake SV, right atrium and ventricle have distinct patterns of ionic currents, but the resulting electrical activity is similar in atrium and SV.

Documenting Changes in Mammal Communities in the Northern Everglades

Restoration of the Everglades is an ambitious endeavor to revitalize its communities and ecosystem health, but there remain gaps in our understanding of mammal communities due to lack of long-term data synthesis. Using secondary data from long-term surveys, this study examines the potential impacts of changes in hydrological management on mammal communities within a state wildlife management area in the northern Everglades. The installation of a pump station in 1991 began a 15-year period of active water management associated with hydrological restoration. Infrastructural damage in late 2005 resulted in 9 years of no significant active inflows. I calculated non-cervid mammal encounter rates from data gathered during perimeter levee surveys over a 10-year period. Mammal encounter rates showed a strong declining trend during the time after the pump failure. A similar analysis for an adjacent management area, which did not suffer an interruption in pump inflows, also showed a decline in mammal encounter rates. In addition, I replicated a small-mammal trapping survey conducted in the mid 1990s. Results showed a decline in diversity of small mammals in the focal area. Recent confirmation of Python molurus (Burmese Python) in the area and the expansion of Canis latrans (Coyote) are likely to have played a role in these apparent declines. Thus, establishing baseline estimates of relative abundance are critical for conservation efforts. With increasingly limited resources, it is important to maximize the utility of data that has already been collected.

Effects of feeding and digestion on myocardial contractility and expression of calcium-handling proteins in Burmese pythons (Python molurus).

Pythons are important models of studies on postprandial metabolism because their physiological responses are exacerbated when digesting large prey. Prior studies of these animals have shown hypertrophy of the cardiac tissue 2 to 3 days after feeding, coinciding with the peak of the specific dynamic action (SDA), but the consequences of this remodeling in myocardial contractility have not been studied, which is the purpose of this work. Specimens of Python molurus were divided into two groups: a Digesting group (2 days after feeding, at the peak of SDA), and a Fasting group (28 days after feeding). When compared to the Fasting group, the Digesting group showed higher relative ventricular mass and calcium-handling protein expression such as sarcoplasmic reticulum Ca2+-ATPase (SERCA), phospholamban (PLB), and the Na+/Ca2+ exchanger (NCX). Digesting pythons also exhibited significant increases in the cardiac contraction force (Fc), rates of force development and relaxation, and cardiac pumping capacity. Therefore, the higher SERCA, PLB and NCX expression levels increased cytosolic Ca2+ transient amplitude, improving myofilament force. These changes are crucial to maintain cardiac output and a relatively high and continuous blood flow required by metabolic expenditure that occurs in postprandial animals.