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At least 19 recordsLinked to original sources
PubMed1983

Fine structure and organization of the infrared receptor relays: lateral descending nucleus of V in Boidae and nucleus reticularis caloris in the rattlesnake.

The morphology of the lateral descending nucleus of V (LTTD) in three species of Boidae and nucleus reticularis caloris (RC) of the rattlesnake have been studied with the light and electron microscope. First- and second-order relays in the infrared receptor pathway to the tectum are contained within LTTD in the Boidae, whereas in the rattlesnakes the secondary relay to tectipetal neurons is in nucleus RC. The lateral descending nucleus in the boids contains small and large neurons. The larger cells project to the optic tectum and morphologically are quite similar to those of nucleus RC. It has been determined at the ultrastructural level that LTTD of the three species of boids studied have very similar morphology and organization. A marginal neuropil, located near the lateral descending tract, consists of terminals of thin unmyelinated axons in synaptic contact with thin dendrites. Deeper within the nucleus primary afferent terminals containing clear spherical vesicles form synaptic clusters with dendrites and are post-synaptic to other axon terminals containing pleomorphic vesicles. The large, tectipetal neurons are postsynaptic to two morphological types of synapses, one with clear spherical vesicles, asymmetric membranes, and subsynaptic web and the other with flattened vesicles and symmetrical membranes. Similar synapses are also present on the cells of nucleus RC in the rattlesnake. There is a close similarity in function, structure, and synaptic organization between the LTTD and boids and the LTTD plus nucleus RC of pit vipers, suggesting similar or identical evolutionary origin.

Animals↗
PubMed1983

Primary vagal nerve projections to the lateral descending trigeminal nucleus in boidae (Python molurus and Boa constrictor).

The primary vagal axons and terminals within the lateral descending trigeminal tract (dlv) and nucleus (DLV) of two species of Boidae are studied following HRP injections of the vagal nerve. Labeled fibers and terminals are found in the tail portion of the dlv and DLV, partly forming a neuropil at its margin. The labeled thin fibers and neuropil seem to correspond to the C-fibers and marginal neuropil of Crotalinae.

Afferent Pathways↗
PubMed2001

Mitochondrial DNA-Based phylogeography of North American rubber boas, Charina bottae (Serpentes: Boidae).

We used 783 bp of mitochondrial DNA sequences to study the phylogeography of Charina bottae (rubber boa) in western North America, with an emphasis on populations from California (U.S.A.). Maximum-parsimony and maximum-likelihood methods identified a basal divergence within C. bottae that corresponds to southern and northern segments of its current distribution. These clades coincide with the ranges of the two recognized subspecies, C. b. umbratica in the south and C. b. bottae to the north. A subsequent cladogenetic event in the C. b. bottae clade resulted in two groupings, which we refer to as the Sierra Nevada and the Northwestern subclades, based on the geographic distribution of their constituent populations. The two subclades have completely allopatric distributions, with a genetic break in the vicinity of Lassen Volcanic National Park in northeastern California, an area that was subjected to glaciation during the Pleistocene and that has been volcanically active in the past 100 years. An earlier genetic study documented fixed differences between populations of bottae and umbratica in four of seven allozymes surveyed, and despite noticeable variation and overlap in the characters that define C. b. bottae and C. b. umbratica, the two forms still can be separated in most cases using a suite of morphological traits. All available evidence thus indicates that C. b. umbratica is a genetically cohesive, allopatric taxon that is morphologically diagnosable, and we conclude that it is an independent evolutionary unit that should be recognized as a distinct species, Charina umbratica.

Animals↗
PubMed1992

[The organ topography of nonpoisonous snakes of the Boidae (boas and pythons) and Colubridae (adders) families].

In order to assist veterinarians with the diagnosis of diseases in snakes, the organ topography of 142 dissected snakes of 35 different species was analysed and examined in relation to body size and normal biotope. Apart from characteristic species specific differences, it was shown that there is a clear difference between arboreal and terrestrial snakes. It was recorded that nearly in all species the organs shifted along the body in relation to increase in growth.

Animals↗
PubMed1995

Origin of West Indian populations of the geographically widespread boa Corallus enydris inferred from mitochondrial DNA sequences.

Corallus enydris (Serpentes: Boidae: Boinae) is an arboreal snake with an extremely wide mainland distribution from southern Costa Rica to southeastern Brazil and is one of two boine species that has invaded the Lesser Antilles (Grenada Bank and St. Vincent). Mitochondrial DNA sequences of samples from seven geographically disparate localities provided evidence of phylogenetic relationships. The monophyly of C. enydris is corroborated and a major dichotomy between northern samples (Panama and Trinidad) and southern samples (Guyana, Perú, southeastern Brazil) was found and corresponds to the two currently recognized subspecies. Unexpectedly, the two samples from the West Indies (southern Lesser Antilles) cluster with the southern rather than the geographically closer northern samples (e.g., Trinidad). The results imply a fairly recent Guianan-Amazonian origin of West Indian populations.

Animals↗
PubMed1998

Hemolytic activity of Monocercomonas spp.

The hemolytic activity of an isolate of Monocercomonas spp. from Tropidophis melanurus (snake: Boidae) was investigated. The isolate was tested against human erythrocytes of groups A, B, AB and O and against erythrocytes of six adult animals of different species (rabbit, rat, chicken, horse, bovine, and sheep). Results show that Monocercomonas spp. exerted an hemolytic activity against all erythrocytes tested.

Animals↗
PubMedDate not supplied

Salmon: a new autosomal mutation demonstrating incomplete dominance in the boine snake Boa constrictor.

An unusual and attractive pigmentation pattern mutation termed "salmon" has been identified in the United States in several captive colonies of the common neotropical boine snake boa constrictor [Boa constrictor (Boidae)]. Boa constrictors expressing the Sa pigmentation pattern appear to be restricted to regions of Panama. Animals with the Sa phenotype exhibit a sharp decrease in melanophore pigments (e.g., melanin) and an increase of xanthophore pigments (e.g., pteridines and carotenoids) throughout the body, including ventral and caudal regions. Moreover, the dorsal saddles (blotches) and lateral diamond patterns are greatly reduced and/or absent. Our study was initiated using a female B. constrictor born in captivity and expressed the Sa pigmentation pattern. Results from breeding experiments indicated an inheritance mode of autosomal incomplete dominance for the Sa and Wt alleles.

Alleles↗
PubMed1984

Vagal afferent C fibers projecting to the lateral descending trigeminal complex of crotaline snakes.

The primary vagal axons and terminals in the lateral descending trigeminal complex (dlv-DLV complex) in crotaline snakes were studied following HRP injections into the vagal nerve. Labeled fibers and terminals were found in the marginal neuropil, which was made up entirely of unmyelinated fibers, i.e., C fibers. The general features of vagal input to the dlv-DLV complex in snakes with infrared sensitivity (Boidae and Crotalinae) are discussed.

Afferent Pathways↗
PubMed1976

Satellite DNA and evolution of sex chromosomes.

The satellite DNA (SATELLITE III) which is mainly represented in the female of Elaphe radiata (Ophidia, Colubridae) has been isolated and its buoyant density has been determined (delta equals 1.700 g cm-3). In situ hybridisation of radioactive complementary RNA of this satellite DNA with the chromosomes of different species has revealed that it is mainly concentrated on the W sex chromosome and its sequences are conserved throughout the sub-order Ophidia. From hybridisation studies these sequences are absent from the primitive family Boidae which represents a primitive state of differentiation of sex chromosomes. Chromosome analysis and C-banding have also revealed the absence of heteromorphism and of an entirely heterochromatic chromosome in the species belonging to the primitive family and their presence in the species of highly evolved families. It is suggested that the origin of satellite DNA (satellite III) in the W chromosome is the first step in differentiation of W from the Z in snakes by generating asynchrony in the DNA replication pattern of Z and W chromosomes and thus conceivably reducing the frequency of crossing-over between them which is the prerequisite of differentiation of sex chromosomes. Presence of similar sex chromosome associated satellite DNA in domestic chicken suggests its existence in a wider range of vertebrates than just the snakes.

Animals↗
PubMed1975

Static and dynamic activity of warm receptors in Boa constrictor.

Afferent impulses from multi- and single-fiber preparations of the trigeminal nerve in Boa constrictor were recorded during exactly controlled thermal stimulation of the receptive field in the labial region. At constant temperatures in the range between 18 and 37 degrees C, multi-fiber preparations showed a continuous discharge with a maximum around 30 degrees C. Dynamic warming caused a high increase of the discharge, whereas dynamic cooling led to a complete inhibition. No cold-sensitive fivers have been found. Mechanical stimulation elicited large spikes from specific mechanoreceptors. Single-fiber preparations from labial warm receptors did not respond to mechanical stimulation. Their discharge was always regular at constant temperatures. The average frequency of a warm receptor population was zero at about 18 degrees C, reached a maximum of 13 sec-1 at 30 degrees C and fell again to zero at 37 degrees C. In addition, a few warm receptors increased their static discharge with temperature up to 36 degrees C, the highest frequency being 38 sec-1. Stepwise warming by delta T = + 5 degrees C caused a marked overshoot in frequency, after which the discharge usually fell to a minimum and then rose again to a new static level. Stepwise cooling by delta T = MINUS 5 DEGREES C led to a transient inhibition of activity followed by an increase until the new static level was reached. In the first group of warm receptors the height of the dynamic overshoot varied with the adapting temperature, the largest average overshoot of 160 sec-1 occurring at an adapting temperature of 30 degrees C. These receptors have their static maximum as well as their highest dynamic sensitivity in the temperature range of the natural tropical habitat of Boidae.

Animals↗
PubMed1987

Resting metabolic rates in boid snakes: allometric relationships and temperature effects.

Resting metabolic rates (RMR) of 34 species from 18 genera of boas and pythons (Serpentes: Boidae), with body masses ranging from 2 to 67,800 g, were determined as oxygen consumption (VO2) and carbon dioxide production (VCO2) at three ambient temperatures (Ta). The temperature coefficient of metabolism (Q10) averaged 2.61 between Ta of 20-30 degrees C and 2.65 between 30 and 34 degrees C. The respiratory exchange ratio RE (= VCO2/VO2) increased slightly with increasing Ta (0.795 at 20 degrees C, 0.819 at 30 degrees C, and 0.834 at 34 degrees C). Interspecific differences in Q10 and RE were slight or insignificant. A multiple regression relating metabolism (VO2) to mass and Ta explained 97% of the variance in the pooled interspecific data. The mass exponent was 0.806, which is approximately the same as reported for squamates and for all reptilian taxa combined. The mean within-species slope (0.732) was significantly less than the slope for pooled data, but did not differ significantly from 0.75. In 40 of 42 cases (14 species at 3 Ta), within-species slopes did not differ from each other. Values of the adjusted mean Y, from covariance analysis, were significantly and positively correlated with mass, indicating that the mass coefficient increases with increasing mass. Considerable variation in metabolic rate is apparent both within and between ecological and taxonomic categories.

Acclimatization↗
PubMed1999

Horizontal transfer of non-LTR retrotransposons in vertebrates.

Since their discovery in family Bovidae (bovids), Bov-B LINEs, believed to be order-specific SINEs, have been found in all ruminants and recently also in Viperidae snakes. The distribution and the evolutionary relationships of Bov-B LINEs provide an indication of their origin and evolutionary dynamics in different species. The evolutionary origin of Bov-B LINE elements has been shown unequivocally to be in Squamata (squamates). The horizontal transfer of Bov-B LINE elements in vertebrates has been confirmed by their discontinuous phylogenetic distribution in Squamata (Serpentes and two lizard infra-orders) as well as in Ruminantia, by the high level of nucleotide identity, and by their phylogenetic relationships. The direction of horizontal transfer from Squamata to the ancestor of Ruminantia is evident from the genetic distances and discontinuous phylogenetic distribution of Bov-B LINE elements. The ancestral snake lineage (Boidae) has been recognized as a possible donor of Bov-B LINE elements to Ruminantia. The timing of horizontal transfer has been estimated from the distribution of Bov-B LINE elements in Ruminantia and the fossil data of Ruminantia to be 40-50 mya. The phylogenetic relationships of Bov-B LINE elements from the various Squamata species agrees with that of the species phylogeny, suggesting that Bov-B LINE elements have been stably maintained by vertical transmission since the origin of Squamata in the Mesozoic era.

Animals↗
PubMed2000

The life-cycle and ultrastructure of Sarcocystis ameivamastigodryasi n. sp., in the lizard Ameiva ameiva (Teiidae) and the snake Mastigodryas bifossatus (Colubridae).

Sarcocysts in muscles of the teiid lizard Ameiva ameiva from north Brazil were fed to the colubrid snake Mastigodryas bifossatus, the faeces of which had been shown to be devoid of coccidial oocysts or sporocysts. When necropsied 16 days later the snake was shown to have developed a massive intestinal infection of Sarcocystis. Mature sporocysts from another, naturally infected M. bifossatus were fed to juvenile specimens of A. ameiva in which no sarcocysts could be detected in tail muscle biopsies. When examined 30 and 47 days later they had very large numbers of sarcocysts in their tail and tongue muscles. The parasite is given the name of Sarcocystis ameivamastigodryasi n. sp. An ultrastructural study has been made of the sarcocyst and of the parasite's sporulation in the lamina propria of the snake: the latter provides details of the wall formation process in developing sporocysts. Attempts to infect a specimen of the boid Boa constrictor constrictor by feeding it with infected Ameiva failed, suggesting that sporocysts previously recorded in genera of the family Boidae may be those of a different species of Sarcocystis.

Animals↗