Armadillo Dasypus Novemcinctus Research Articles

Diversity in Paracoccidioides brasiliensis . The PbGP43 gene as a genetic marker

Paracoccidioides brasiliensis is a temperature-dependent dimorphic fungus and the agent of paracoccidioidomycosis (PCM), which is prevalent in rural workers of Latin American countries. Until a decade ago, most of the studies involving P. brasiliensis used clinical isolates, since environmental samples from soil are difficult to obtain. More recently, P. brasiliensis has been isolated from infected wild and domestic animals, especially from the nine-banded armadillo Dasypus novemcinctus in Brazil. Over the years, diversity within the species has been observed at several phenotypic levels. The present review will discuss the reports focusing on genetic polymorphism, which culminated with the detection of P. brasiliensis phylogenetic species as a result of a multilocus study. Polymorphism in the PbGP43 gene is detailed. This gene encodes fungal glycoprotein gp43, a dominant P. brasiliensis antigen largely studied in the last two decades for its importance in diagnosis, immune protection, and adhesive properties to extracellular matrix-associated proteins. Fungal traits associated with genetic groups are discussed.

Osteoderm morphology and development in the nine‐banded armadillo, Dasypus novemcinctus (Mammalia, Xenarthra, Cingulata)

Among modern mammals, armadillos (Xenarthra, Cingulata) are the only group that possesses osteoderms, bony inclusions within the integument. Along the body, osteoderms are organized into five discrete assemblages: the head, pectoral, banded, pelvic, and tail shields. The pectoral, banded, and pelvic shields articulate to form the carapace. We examined osteoderm skeletogenesis in the armadillo Dasypus novemcinctus using serial and whole-mount histochemistry. Compared with the rest of the skeleton, osteoderms have a delayed onset of development. Skeletogenesis begins as condensations of osteoblasts secreting osteoid, localized within the papillary layer of the dermis. Osteoderm formation is asynchronous both within each shield and across the body. The first osteoderms to mineralize are situated within the pectoral shield of the carapace, followed by elements within the banded, head, pelvic, and tail shields. In general, within each shield ossification begins craniomedially and proceeds caudally and laterally, except over the head, where the earliest elements form over the frontal and parietal bones. The absence of cartilage precursors indicates that osteoderms are dermal elements, possibly related to the all-encompassing vertebrate dermal skeleton (exoskeleton). The mode of development of D. novemcinctus osteoderms is unlike that described for squamate osteoderms, which arise via bone metaplasia, and instead is comparable with intramembranously derived elements of the skull.

Jaguar (Panthera onca) feeding ecology: distribution of predator and prey through time and space

AbstractJaguars Panthera onca inhabiting tropical or subtropical evergreen moist forest have often been classified as opportunistic predators because they consume prey relative to its availability. However, these studies failed to address simultaneously the distribution of predator and prey through time and space, which may lead to an incomplete or erroneous understanding of jaguar foraging strategies. In this study, we reconstructed jaguar diet from scat, and used camera traps to investigate jaguar prey availability and the distribution of jaguar and its prey through space and time. We focused our examination of predator–prey temporal and spatial relations on forest infrastructure comprising man‐made paths, small mammal trails, tapir Tapirus bairdi trail and trail‐less, forested areas as they represent distinct habitats for prey selection. Overall, we observed high overlap between the prey used and available, suggestive of opportunistic foraging. However, jaguars exhibited selective tendencies in discriminating between larger prey. Jaguars used collared peccary Tayassu tajacu greater than its availability, while preying upon the equally abundant and similarly distributed white‐lipped peccary Tayassu pecari and tapir less than predicted based upon availability. Armadillo Dasypus novemcinctus and paca Agouti paca, 56.6% of total consumption, were consumed relative to availability but exhibited low spatial overlap with jaguar. Armadillo and paca used trail‐less, forested areas and small mammal trails not used by jaguar and were photographed more frequently at greater distances from man‐made paths, major thoroughfares for jaguars. This study suggests that although forest jaguars use prey relative to its abundance, jaguars may rely on foraging strategies other than chance encounters for exploiting prey.

Foraging ecology of jaguar (Panthera onca) and puma (Puma concolor) in hunted and non‐hunted sites within the Maya Biosphere Reserve, Guatemala

AbstractSubsistence hunting and commercial exploitation directly influence wildlife populations in many regions of Central and South America. Where prey populations are exploited, the foraging ecology of top‐level predators can be effected negatively. This study assessed the food habits and prey selection of jaguar Panthera onca and puma Puma concolor within hunted and non‐hunted segments of the Maya Biosphere Reserve (MBR), Guatemala. Food habits were determined from analysis of 76 jaguar and 145 puma scats collected within hunted and non‐hunted areas of the MBR from February 2000 to August 2001. Diets of jaguar and puma were compared (1) within species between areas with and without hunting to evaluate effects of subsistence hunting, and (2) between species to evaluate resource partitioning between these sympatric carnivores. Origin of predator scats was determined from mitochondrial DNA, diets were determined from prey remnants found within scats, and frequency of prey in scats was compared to expected values based on prey density estimates to test the hypothesis that diets of jaguar and puma were selective. Densities of major prey species were estimated using line‐transect sampling. White‐lipped peccary Tayassu pecari, collared peccary Tayassu tajacu and brocket deer Mazama sp. were less abundant, and coatis Nasua nasua more abundant, in the hunted area than in the non‐hunted area. Jaguar and puma in both hunted and non‐hunted sites obtained similar dietary contributions from large prey to their respective diets despite differences in the abundance of these prey species. Diets of jaguar and puma, as measured by percentage biomass occurrence of prey species, did not differ between hunted and non‐hunted areas. Jaguar diets were dominated by medium‐sized prey, particularly armadillos Dasypus novemcinctus and coatis, in both hunted and non‐hunted areas. Medium‐sized mammals also were prominent in puma diets, but large mammals constituted approximately 50% of prey biomass in both hunted and non‐hunted areas. Deer Odocoileus virginianus and Mazama sp. and large rodents Agouti paca and Dasyprocta punctata were the most important prey of puma. Dietary overlap between jaguar and puma in both hunted and non‐hunted areas was low.

Partial characterization of phagocytic activity in neutrophils of the nine-banded armadillo Dasypus novemcinctus

Though the armadillo is important as a research model in leprosy studies, the activity of armadillo's neutrophils is an aspect of little research. The aim of this study was carried out to partially characterize the chemotaxis, endocytosis and bacteriocidal ability of the neutrophils found in the nine-banded armadillo ( Dasypus novemcinctus) . Results showed that the chemotactic activity of the neutrophils, evaluated by the movement of the neutrophils through a nitrocellulose membrane (5 μm) in response to a chemo-attractive substance, was greater towards the armadillo serum (5.16 ± 1.35 migration index, p < 0.05) than towards the formil methionyl leucil phenylalanine (fMLP, 1.43 ± 0.18 migration index) or human serum (0.56 ± 0.18 migration index). Regarding endocytic capacity of the neutrophils and the monocytes against Escherichia coli was evaluated by a flow cytometry and using opsonized and non-opsonized E. coli-FITC at the following incubation times: 5, 10, 20, 30 and 60 min. The largest percentage of endocytosis by the neutrophils was 92.32 ± 0.12% with opsonized bacteria and 77.73 ± 14.33% with non-opsonized bacteria at 10 min incubation time, while the largest percentage of endocytosis by monocytes was 89.94 ± 1.40% with opsonized bacteria and 73.07 ± 15.6% with non-opsonized bacteria at 20 min incubation time. Evaluation of the bacteriocidal capacity of neutrophils using the methyl-thiazol-tetrazolium salts (MTT) reduction color-measurement assay showed an 89.0 ± 10% mortality rate of non-opsonized E. coli and 89.0 + 10% of opsonized E. coli. In conclusion, the armadillo neutrophils show a good phagocytosis and bacteriocidal activity; however, a deficiency in the migration towards the fMLP was observed. This deficiency could be a cause so that the armadillo neutrophils do not respond quickly to invading microorganism.

Morphological, molecular and ecological aspects of the South American hypogeous fungus Alpova austroalnicola sp. nov.

Field studies in Argentina’s Yunga District revealed Alpova austroalnicola sp. nov., a hypogeous fungus associated with Alnus acuminata ssp. acuminata. Morphological and molecular studies based on amplification and sequencing of the nuclear LSU rDNA gene showed its unique identity within Alpova. Related genera included in the analyses were Boletus edulis, Rhizopogon spp., Suillus luteus and Truncocolumella citrina. Additional observations of animal diggings around the sites and microscopic examination of fecal pellets of the nine-banded armadillo (Dasypus novemcinctus novemcinctus) indicate A. austroalnicola is consumed and its spores dispersed by animals.

Morphological, molecular and ecological aspects of the South American hypogeous fungus Alpova austroalnicola sp. nov.

Field studies in Argentina's Yunga District revealed Alpova austroalnicola sp. nov., a hypogeous fungus associated with Alnus acuminata ssp. acuminata. Morphological and molecular studies based on amplification and sequencing of the nuclear LSU rDNA gene showed its unique identity within Alpova. Related genera included in the analyses were Boletus edulis, Rhizopogon spp., Suillus luteus and Truncocolumella citrina. Additional observations of animal diggings around the sites and microscopic examination of fecal pellets of the nine-banded armadillo (Dasypus novemcinctus novemcinctus) indicate A. austroalnicola is consumed and its spores dispersed by animals.

A Novel Abundant Family of Retroposed Elements (DAS-SINEs) in the Nine-Banded Armadillo (Dasypus novemcinctus)

About half of the mammalian genome is composed of retroposons. Long interspersed elements (LINEs) and short interspersed elements (SINEs) are the most abundant repetitive elements and account for about 21% and 13% of the human genome, respectively. SINEs have been detected in all major mammalian lineages, except for the South American order Xenarthra, also termed Edentata (armadillos, anteaters, and sloths). Investigating this order, we discovered a novel high-copy-number family of tRNA derived SINEs in the nine-banded armadillo Dasypus novemcinctus, a species that successfully crossed the Central American land bridge to North America in the Pliocene. A specific computer algorithm was developed, and we detected and extracted 687 specific SINEs from databases. Termed DAS-SINEs, we further divided them into six distinct subfamilies. We extracted tRNA(Ala)-derived monomers, two types of dimers, and three subfamilies of chimeric fusion products of a tRNA(Ala) domain and an approximately 180-nt sequence of thus far unidentified origin. Comparisons of secondary structures of the DAS-SINEs' tRNA domains suggest selective pressure to maintain a tRNA-like D-arm structure in the respective founder RNAs, as shown by compensatory mutations. By analysis of subfamily-specific genetic variability, comparison of the proportion of direct repeats, and analysis of self-integrations as well as key events of dimerization and deletions or insertions, we were able to delineate the evolutionary history of the DAS-SINE subfamilies.

The naked-tailed armadilloCabassous centralis(Miller 1899): a new host toParacoccidioides brasiliensis. Molecular identification of the isolate

The natural habitat of Paracoccidioides brasiliensis remains undefined but the repeated demonstration of infection by this fungus in the nine-banded armadillo Dasypus novemcinctus has opened interesting research avenues. We report here the isolation of this fungus from the spleen of a naked-tailed armadillo Cabassous centralis (Miller 1899) captured in a coffee farm localized in the Colombian endemic area for paracoccidioidomycosis. This particular isolate was identified by its dimorphism and also by comparison of the PbGP43 gene and ribosomal internal transcribed spacer regions (ITS) with recognized P brasiliensis strains. This finding extends the range of naturally acquired infections in mammals of the family Dasypodidae and confirms the existence of this human pathogen in areas where human paracoccidioidomycosis is known to occur.

Individual variation in metabolic traits of wild nine-banded armadillos (Dasypus novemcinctus), and the aerobic capacity model for the evolution of endothermy.

A fundamental assumption of the aerobic capacity model for the evolution of endothermy is that basal (BMR) and peak (PMR) metabolic rates are functionally linked at the intraspecific level. The purpose of this study was to use the nine-banded armadillo Dasypus novemcinctus as a model to test this assumption. Measurements of BMR, PMR, mass and rectal temperature were obtained over two summers from wild, adult individuals from a population in Louisiana, USA. BMR and PMR were positively correlated (r=0.62), and both were significantly higher (by 46% for BMR and by 35% for PMR) in 1999 than in 1998. Similar results were obtained whether metabolic rates were expressed in whole-animal or mass-independent units. These results suggest the existence of a functional link between BMR and PMR and are therefore consistent with the aerobic capacity model. In addition, this study confirmed that, compared with most eutherian mammals, the nine-banded armadillo exhibits low and highly variable basal and peak metabolic rates (20-60% the predicted values; 23% and 27% coefficients of variation) and rectal temperatures (range 32.7-35.3 degrees C). Such metabolic traits are, however, consistent with the general pattern previously observed for other members of the order Xenarthra and with the hypothesis that low metabolic rates in armored mammals evolved as a result of unbalanced selection in which, because of low predation risks, selection for a high aerobic capacity was much weaker than the opposing selection for energy conservation.

GENETIC DIVERSITY AND GENE FLOW IN NINE-BANDED ARMADILLOS IN PARAGUAY

Genetic diversity and gene flow were examined within and among populations of nine-banded armadillos (Dasypus novemcinctus) from Paraguay. Although D. novemcinctus is hunted regularly and constitutes an important protein resource in Paraguay, no conservation or management program exists for this species. To contribute toward conservation planning for this species, we examined intra- and interpopulation DNA sequence variation in the mitochondrial cytochrome-b gene from 75 specimens representing 5 populations from Paraguay. Twenty-five haplotypes were identified among the 75 individuals examined. Haplotype diversity (h) and nucleotide diversity (π) ranged from 0.68 to 0.94 and 0.003 to 0.005, respectively. Although genetic homogeneity was observed among all 5 populations, nested-clade analysis revealed continuous range expansion, isolation by distance, and long-distance dispersal of female nine-banded armadillos.

Correlates of reproductive success in a population of nine-banded armadillos

We used microsatellite DNA markers to identify the putative parents of 69 litters of nine-banded armadillos (Dasypus novemcinctus) over 4 years. Male and female parents did not differ in any measure of body size in comparisons with nonparents. However, males observed paired with a female were significantly larger than unpaired males, although paired females were the same size as unpaired females. Females categorized as possibly lactating were significantly larger than females that were either definitely lactating or definitely not lactating. There was no evidence of assortative mating: body-size measurements of mothers were not significantly correlated with those of fathers. Nine-banded armadillos give birth to litters of genetically identical quadruplets. Mothers (but not fathers) of female litters were significantly larger than mothers of male litters, and maternal (but not paternal) body size was positively correlated with the number of surviving young within years, but not cumulatively. There were no differences in dates of birth between male and female litters, nor were there any significant relationships between birth date and maternal body size. Body size of either parent was not correlated with the body sizes of their offspring. Cumulative and yearly reproductive success did not differ between reproductively successful males and females. Average reproductive success (which included apparently unsuccessful individuals) also did not differ between males and females. The majority of adults in the population apparently failed to produce any surviving offspring, and even those that did usually did so in only 1 of the 4 years. This low reproductive success is unexpected, given the rapid and successful range extension of this species throughout the southeastern United States in this century.

Chagas disease in the Amazon Basin: association of Panstrongylus geniculatus (Hemiptera: Reduviidae) with domestic pigs.

Just over 100 autochthonous cases of Chagas disease are reported from the Brazilian Amazon Basin. Panstrongylus geniculatus (Latreille) occurs throughout the region and is the known vector of Trypanosoma cruzi, principal zymodeme 3 (Z3) to the armadillo Dasypus novemcinctus. In the small riverine community of Furo do Rio Pau Grande, pigsties adjoining houses were heavily infested with P. geniculatus, which repeatedly attacked local inhabitants. Palm trees in the immediate vicinity were also infested. T. cruzi principal zymodeme 1 (Z1) was isolated from P. geniculatus, domestic pigs, and opossums, but no human infections were detected. The threat of endemic Chagas disease to the Amazon Basin from either domiciliation of local silvatic triatomine species, or from migration of domestic vectors, demands a program of vigilance and plans of action to eliminate household triatomine colonies.

Pathogenicities and GP43kDa gene of three Paracoccidioides brasiliensis isolates originated from a nine-banded armadillo (Dasypus novemcinctus).

We studied three different isolates of Paracoccidioides brasiliensis obtained from the mesenteric lymph node (D3LY1), the spleen (D3S1) and the liver (D3LIV1) of the same armadillo (Dasypus novemcinctus). Pulmonal inflammatory area was evaluated by intravenous inoculation of 10(6) yeast cells of each isolates in young, male, ddY mice. Moreover, the partial sequence of GP43kDa gene of P. brasiliensis was analyzed. The lung inflammatory area was greater in animals inoculated with isolate D3S1. The partial sequence of GP43kDa gene indicated that isolate D3S1 is different from isolates D3LY1 and D3LIV1. This study suggested that the same armadillo might be susceptible to multiple P. brasiliensis isolates simultaneously.

Genetic Maternity and Paternity in a Local Population of Armadillos Assessed by Microsatellite DNA Markers and Field Data

Genetic data from polymorphic microsatellite loci were employed to estimate paternity and maternity in a local population of nine-banded armadillos (Dasypus novemcinctus) in northern Florida. The parentage assessments took advantage of maximum likelihood procedures developed expressly for situations when individuals of neither gender can be excluded a priori as candidate parents. The molecular data for 290 individuals, interpreted alone and in conjunction with detailed biological and spatial information for the population, demonstrate high exclusion probabilities and reasonably strong likelihoods of genetic parentage assignment in many cases; low mean probabilities of successful reproductive contribution to the local population by individual armadillo adults in a given year; and statistically significant microspatial associations of parents and their offspring. Results suggest that molecular assays of highly polymorphic genetic systems can add considerable power to assessments of biological parentage in natural populations even when neither parent is otherwise known.

Role of the armadillo Dasypus novemcinctus in the epidemiology of paracoccidioidomycosis.

A study conducted in a rural area of Ibiá, State of Minas Gerais, Brazil, where Paracoccidioides brasiliensis was recently isolated from soil, sought to determine if the armadillo Dasypus novemcinctus developed paracoccidioidomycosis. Out of 21 armadillos captured in the area, one had a lung granuloma containing fungal cells attributable to those of P. brasiliensis. The present report presents the first histopathological evidence for the presence of this pathogen in the lungs of an armadillo. This finding permitted us to establish a linkage between the two species and to suggest that fungal infections of humans and of armadillos occur in the same agricultural and forest microenvironment that they share.

Pairing Behavior of the Nine-banded Armadillo (Dasypus novemcinctus)

-Data on pairing behavior of nine-banded armadillos (Dasypus novemcinctus) were collected for 4 yr in a marked population in S Texas. A pair consisted of a male and female maintaining proximity (<10 m) without aggression, pairing behavior involved those behaviors exhibited during this interaction. Some of these behaviors were only observed during pairing. Males were responsible for maintaining proximity to females through repeated approaches and by monitoring their surroundings for the location or movement of the female (i.e., exhibiting vigilance). The incidences of some behaviors were significantly associated with others, specifically dorsal touches by males elicited tail-wagging by females. Tail-wagging probably facilitated the transmission of olfactory information about female receptivity. After tail-wagging the male was more likely to contact and sniff. Contacts, which occurred in every pairing event were positively correlated with sniffs and tail-wagging and might be used as an index of receptivity. Pairing behavior apparently generated a cost of reduced foraging time for males by increasing their vigilance levels.

Are Road Kills Valid Indicators of Armadillo Population Structure?

-We collected 3 yr of data on road-killed nine-banded armadillos (Dasypus novemcinctus) to determine if these individuals were representative of the population as a whole. Comparisons between road kills and an adjacent live-caught population revealed no differences in sex ratios or the reproductive condition of adult females. However, there was a significant difference in the age structure of the two groups, with almost no juvenile road kills. Our live-caught population appeared representative of armadillo populations in general. Comparisons of the demography of this population with that from two other live-caught groups revealed no significant differences. Our data suggest that road-killed armadillos provide a representative picture of the demography of the adults in a population, but that information on age structure is misleading.

Pathological and Reproductive Effects of Intraperitoneal Telemetry Devices on Female Armadillos

I compared gross pathological effects for 2 methods of placing intraperitoneal telemetry devices in female armadillos (Dasypus novemcinctus). Placing radio transmitters free in the peritoneal cavity resulted in ensheathment by the greater omentum without obvious detrimental effects. The use of retaining sutures required longer incision lengths and failed to hold the device in place in 2 cases. Retaining sutures also resulted in adhesions involving the gastrointestinal tract in 1 case and death following bowel entrapment in another. Two females successfully conceived while carrying free-floating devices and carried their pregnancies to term despite undergoing second surgeries

Trypanosomes of the subgenus Megatrypanum from armadillos (Xenarthra: Dasypodidae)

A new species of trypanosome, Trypanosoma (Megatrypanum) peba, is described from the peripheral blood of the armadillo Euphractus sexcinctus setosus from Bahia State, Brazil. Ten out of 29 specimens of the armadillo Dasypus novemcinctus from Pará State were found to have trypanosomes, including epimastigote forms, in impression smears of subcutaneous lymph nodes. The trypanosomes from D. novemcinctus are illustrated and were identified as belonging to the subgenus Megatrypanum on the basis of their general appearance, although they failed to multiply in blood-agar culture medium and no bloodstream forms were seen. This is the first published record of trypanosomes of this subgenus from armadillos and the first demonstration of epimastigote trypanosomes in the mammalian host other than in the bloodstream, or in the anal glands of opossums.