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PubMedDate not supplied

Vampire bats yield potent clot buster for ischemic stroke.

While tissue-type plasminogen activator (tPA) is currently the standard "clot-busting" drug used to treat patients with acute ischemic stroke, another new option for treatment is now under clinical study. Desmodus rotundus plasminogen activator (DSPA), an enzyme found in the saliva of vampire bats, may offer another therapeutic option instead of tPA, a current therapy for stroke. Animal research indicates that tPA may mediate neuronal death as well as increase systemic plasminogen consumption and fibrinogenolysis. Conversely, DSPA's activity is dependent on the presence of fibrin and therefore has not been associated with the systemic plasminogen consumption and fibrinogenolysis that potentially may occur in those receiving tPA. In animal studies, tPA was found to exhibit "inherent neurotoxic properties" not seen with DSPA. In addition, DSPA may be administered up to 9 hours after the onset of symptoms, unlike tPA, which cannot be given after 3 hours without potential risk of additional brain injury. Phase II clinical trials have demonstrated a positive result in human subjects. Phase III trials are currently under way in stroke populations.

Animals↗
PubMed1976

Elastogenesis in healing wounds in bats.

Full-thickness square wounds were made in the webs of fruit bats. Elastin was laid down in the healing scars of these wounds in two forms--as single fibers under the regenerated epidermis, and as bundles of fine fibers taking their origin and orientation from the cut ends of the web elastin bundles. This process continued over a period of 6 months, during which time other components of the scar became reduced in amount. The arrangement of the new elastin in the scar tissue was thus a replica of that seen in the normal web. There are indications in this study that elastin imparts elasticity to the scar.

Animals↗
PubMed1990

Seasonal changes in pancreatic insulin and glucagon in the little brown bat (Myotis lucifugus).

Seasonal changes in pancreatic insulin and glucagon were investigated in the little brown bat (Myotis lucifugus). Pancreatic protein content increased 21% from the nonhibernating state in June compared to the nonhibernating or early hibernating state in late October, and then decreased 50% between October and the months of deep hibernation. The content of insulin and glucagon increased from June to October, and both hormones further increased during hibernation, when a fall in pancreatic protein content occurred. The concentration of both insulin and glucagon increased from October to February. Of note, the insulin concentration progressively increased during deep hibernation from February to April, whereas the glucagon concentration remained constantly elevated throughout this time interval. The persistent elevation of pancreatic glucagon during hibernation may be related to its role in counterregulation and carbohydrate homeostasis during fasting. The elevation of pancreatic insulin, and its further increase during hibernation, is less clear but may be hypothesized to provide a rapidly releasable storage pool required for immediate secretion during arousal, possibly to prevent a hyperosmolar state.

Analysis of Variance↗
PubMed2001

Outbreeding increases offspring survival in wild greater horseshoe bats (Rhinolophus ferrumequinum).

The factors influencing the survival of greater horseshoe bat (Rhinolophus ferrumequinum) offspring born over seven years at a maternity colony in south-west Britain were studied. The effects of a range of phenotypic and maternal variables were analysed using a historical data set. In addition, the influence of two genetic measures on mortality, individual heterozygosity and a new measure of outbreeding, termed mean d(2), was assessed. Logistic regressions were undertaken with survival modelled as a binary response variable. Survival to two life stages was studied for each variable and all models were developed for both sexes separately and together. Only one variable, mean d(2), was significantly associated with survival. Male offspring with high mean d(2) scores were more likely to survive to their first and second summers. The influence of mean d(2) was not due to a single locus under selection but a wider multilocus effect and probably represents heterosis as opposed to solely inbreeding depression. Therefore, the extent to which an individual is outbred may determine survival more than widely used phenotypic characteristics such as size and mass. Mean d(2) may reflect immunocompetence, which influences mortality. Protection of mating sites in order to facilitate gene flow and, therefore, outbreeding may help to promote population stability and growth.

Animals↗
PubMed2005

Sex and segregation in temperate bats.

Many temperate insectivorous bats show marked sexual segregation during the summer, but in spectacular, pre-hibernation swarming, gather at caves to mate. In many species, sexual segregation is probably due to a gradient in aerial insect availability that confines females to lower elevations, where high reproductive costs are met by an abundant and reliable food supply. In the hawking and trawling Myotis daubentonii, we show that alongside inter-sexual segregation, there is intra-male segregation and suggest that this results from the exclusion of most males from high-quality habitat. These apparently excluded males suffer reduced foraging efficiency and mating success relative to males that roost with the females in summer. Changes in resources and behaviour at the end of the summer lead to a change in strategy that gives all males a chance to mate during swarming, but this does not overcome the paternity advantage to males that spend the summer with the females.

Animals↗
PubMed2006

Recurrent replacement of mtDNA and cryptic hybridization between two sibling bat species Myotis myotis and Myotis blythii.

The two sibling bat species Myotis myotis and Myotis blythii occur in sympatry over wide areas of Southern and Central Europe. Morphological, ecological and previous genetic evidence supported the view that the two species constitute two well-differentiated groups, but recent phylogenetic analyses have shown that the two species share some mtDNA haplotypes when they occur in sympatry. In order to see whether some genetic exchange has occurred between the two species, we sequenced a highly variable segment of the mitochondrial control region in both species living in sympatry and in allopatry. We also analysed the nuclear diversity of 160 individuals of both species found in two mixed nursery colonies located north and south of the Alps. MtDNA analysis confirmed that European M. blythii share multiple, identical or very similar haplotypes with M. myotis. Since allopatric Asian M. blythii presents mtDNA sequences that are very divergent from those of the two species found in Europe, we postulate that the mitochondrial genome of the European M. blythii has been replaced by that of M. myotis. The analysis of nuclear diversity shows a strikingly different pattern, as both species are well differentiated within mixed nursery colonies (F(ST) = 0.18). However, a Bayesian analysis of admixture reveals that the hybrids can be frequently observed, as about 25% of sampled M. blythii show introgressed genes of M. myotis origin. In contrast, less than 4% of the M. myotis analysed were classified as non-parental genotypes, revealing an asymmetry in the pattern of hybridization between the two species. These results show that the two species can interbreed and that the hybridization is still ongoing in the areas of sympatry. The persistence of well-differentiated nuclear gene pools, in spite of an apparent replacement of mitochondrial genome in European M. blythii by that of M. myotis, is best explained by a series of introgression events having occurred repeatedly during the recent colonization of Europe by M. blythii from Asia. The sharp contrast obtained from the analysis of mitochondrial and nuclear markers further points to the need to cautiously interpret results based on a single class of genetic markers.

Animals↗
PubMed1978

A plaque assay for Mount Elgon bat virus based on intrinsic interference.

A plaque count infectivity assay was developed in which chick cells infected with the Mount Elgon bat virus were completely resistant to superinfection with large doses of Sendai virus. Several variables markedly affected the assay sensitivity. The defined plaque assay was simple, highly reproducible and sensitive. It allowed determination of virus neutralizing antibody in a simple and reproducible test. Both actinomycin D and 5-iododeoxyuridine were without effect on plaque formation.

Animals↗
PubMed1979

Invasion of mouse brain by Mount Elgon bat virus.

Mount Elgon bat virus killed mice up to 13 days of age when given intranasally. Virus reached the brain of these mice via the olfactory nerve route without obvious multiplication in any tissues other than the nasal mucosa of 1- to 6-day-old mice and in the absence of viraemia or circulating virus neutralizing antibody. Large amounts of interferon were, however, synthesized in brain where virus grew to high titres. In mice older than 13 days virus did not multiply in brain but it reached the olfactory bulbs and persisted until virus neutralizing antibody appeared in the nasopharynx. No antibody was detected in blood of the resistant mice, nor was interferon detected in their brains or nasal mucosa. Immunosuppression of the resistant mice with cyclophosphamide resulted in moderate virus growth in mid- and hind-brain accompanied by interferon synthesis and death of the mice. The local immune response prevented invasion of mid- and hind-brain in the resistant mice.

Animals↗
PubMed1979

The pathogenesis of infection in mouse brain by Mount Elgon bat virus.

Mount Elgon bat virus given intracerebrally readily killed mice up to 12 days of age (1 to 4 p.f.u/LD50). Virus in doses of 10 to 10(6) p.f.u. killed 40 to 80% of weanling mice of both sexes and up to 20% of adult females and 40 to 80% of adult males. Clearance of brain infectivity in the resistant mice coincided with the appearance of circulating virus neutralizing antibody which occurred earliest in the adult female mice. Immunosuppression of adult mice with cyclophosphamide resulted in the death of all the virus-inoculated mice of both sexes. Virus in these mice reached tenfold higher titres and their brains contained 30- to 60-fold more interferon than the brains of infected mice not given cyclophosphamide. Interferon was apparently without effect on the outcome of infection in the brains of resistant mice and its synthesis reflected the extent of virus growth.

Animals↗
PubMed1988

Plasma catecholamine concentrations--changes after infiltration with local anaesthetic solutions and adrenaline during bat-ear surgery.

Plasma catecholamine concentrations were measured in 12 patients who had bilateral bat-ear surgery following infiltration of each ear with 2 ml 2% lignocaine with adrenaline 1:100,000. Venous blood samples were withdrawn before and at set intervals after infiltration. Plasma adrenaline concentration increased from 0.8 pmol/ml to a peak of 2.2 pmol/ml at 2 minutes after infiltration; this is an increase of 175%. There was no significant change in plasma noradrenaline concentration.

Adolescent↗
PubMed1991

T and B cell human responses to European bat lyssavirus after post-exposure rabies vaccination.

T and B cell human responses to European bat lyssavirus (EBL1) induced by post-exposure rabies vaccination (PM virus vaccine) were evaluated by measuring plasmatic titres of EBL1-specific neutralizing antibodies; specific EBL1-binding antibodies; and proliferation indices of peripheral blood lymphocytes stimulated in vitro with EBL1. These parameters for vaccination efficacy were compared with those obtained with vaccine-related viruses (CVS and ERA) and with a non-vaccine-related virus. Mokola virus, the last implicated in vaccination failures. Twenty-two patients exposed to rabies risk who received a reduced rabies post-exposure vaccination were involved in the study. On day 21, vaccine induced CVS-specific neutralizing antibodies in all patients; but EBL1-specific neutralizing antibodies were induced in only 73% of patients. No vaccine had Mokola-specific neutralizing antibodies. Patients having EBL1-specific neutralizing antibodies were usually those in whom vaccination induced high titres of CVS-specific neutralizing antibodies. On day 21, peripheral blood lymphocytes of 86% of patients could be restimulated in vitro with vaccine, 43% with EBL1 and 45% with Mokola. Patients exhibiting a high vaccine-specific proliferation response more likely developed an EBL1- or a Mokola-specific proliferative response. No correlation was found between T and B cell responses. Rabies vaccination induced neither T nor B cell EBL1-specific responses in 22% of patients.

Adult↗
PubMed2004

Exploring population genetic structure in three species of Lesser Antillean bats.

We explore population genetic structure in phyllostomid bats (Ardops nichollsi, Brachyphylla cavernarum and Artibeus jamaicensis) from the northern Lesser Antilles by investigating the degree to which island populations are genetically differentiated. Our hypothesis, that the island populations are genetically distinct because of a combination of founding events, limited migration and genetic drift exacerbated by catastrophe-induced fluctuations in population size, is derived from a priori hypotheses erected in the literature. The first prediction of this hypothesis, that within each species island populations are monophyletic, was tested using a parametric bootstrap approach. Island monophyly could not be rejected in Ardops nichollsi (P = 0.718), but could be rejected in B. cavernarum (P < 0.001) and Artibeus jamaicensis (P < 0.001). A second prediction, that molecular variance is partitioned among islands, was tested using an amova and was rejected in each species [Ardops nichollsi (P = 0.697); B. cavernarum (P = 0.598); Artibeus jamaicensis (P = 0.763)]. In B. cavernarum and Artibeus jamaicensis, the admixture in mitochondrial haplotypes from islands separated by > 100 km of ocean can be explained either by interisland migration or by incomplete lineage sorting of ancestral polymorphism in the source population. As an a posteriori test of lineage sorting, we used simulations of gene trees within a population tree to suggest that lineage sorting is an unlikely explanation for the observed pattern of nonmonophyly in Artibeus jamaicensis (PW < 0.01; PSE = 0.04), but cannot be rejected in B. cavernarum (PW = 0.81; PSE = 0.79). A conservative interpretation of the molecular data is that island populations of Artibeus jamaicensis, although isolated geographically, are not isolated genetically.

Analysis of Variance↗
PubMed2006

History, ocean channels, and distance determine phylogeographic patterns in three widespread Philippine fruit bats (Pteropodidae).

The comparative phylogeography of widespread, codistributed species provides unique insights into regional biodiversity and diversification patterns. I used partial DNA sequences of the mitochondrial genes ND2 and cyt b to investigate phylogeographic structure in three widespread Philippine fruit bats. Ptenochirus jagori is endemic to the oceanic region of the Philippines and is most abundant in lowland primary forest. Macroglossus minimus and Cynopterus brachyotis are most common in disturbed and open habitats and are not endemic. In all three, genetic differentiation is present at multiple spatial scales and is associated to some degree with Pleistocene landbridge island groups. In P. jagori and C. brachyotis, genetic distance is correlated with geographic distance; in C. brachyotis and M. minimus, it is correlated with the sea-crossing distance between islands. P. jagori has the least overall genetic structure of these three species, whereas C. brachyotis and M. minimus have more geographic association among haplotypes, suggesting that phylogeographic patterns are linked to ecology and habitat preference. However, contrary to expectation, the two widespread, disturbed habitat species have more structure than the endemic species. Mismatch distributions suggest rapid changes in effective population size in C. brachyotis and P. jagori, whereas M. minimus appears to be demographically more stable. Geologic and geographic history are important in structuring variation, and phylogeographic patterns are the result of dynamic long-term processes rather than simply reflecting current conditions.

Animals↗
PubMed1976

Field studies on the African fruit bat Epomophorus wahlbergi (Sundevall), with special reference to male calling.

Social interactions, site attachment and group cohesion were studied in a free-living colony of Epomophorus fruit bats. Daily activites in an undisturbed colony were recorded. Special attention was paid to the peculiar calling behavior of courting male during the night. Structure and repetition rate of their sounds were analyzed in the laboratory. A special mode of acoustic interaction was found and related to the observed spacing out of calling males. By following feeding animals in the field and by analysis of their faeces we found that besides fruits they eat special leaves which afford steroidal sapogenins.

Animals↗
PubMed1976

Social organization in the African bat, Myotis boccagei.

In northeastern Gabon (lat.: 0.4 degrees north, long.: 12.5), the social organization of the vespertilionid bat Myotis boccagei was studied. In four groups, all individuals (55) were marked and monitored regularly for 38 months. The basic social organization in Myotis boccagei is the "harem". In each group, a single adult male is invariably found, accompanied by from 2 to 7 adult females and recent young.

Animals↗
PubMed2004

Susceptibility of ferrets (Mustela putorius furo) to experimentally induced rabies with European Bat Lyssaviruses (EBLV).

Twenty ferrets (Mustela putorius furo) were inoculated by intramuscular (i.m.) injection with European Bat Lyssaviruses (EBLV) type-1 and 2 using 10(4.0) foci-forming units (FFU) EBLV-2 (n = 6), 10(4.0) FFU EBLV-1 (n = 7) and 10(6.0) FFU EBLV-1 (n = 7). Furthermore, 15 mice received 10(2.5) FFU EBLV-2 (n = 5), 10(2.5) FFU EBLV-1 (n = 5) and 10(4.5) FFU EBLV-1 (n = 5) by i.m. inoculation. All ferrets and mice receiving the higher dose of EBLV-1 succumbed to infection. In contrast, only three of seven ferrets and two of five mice inoculated experimentally with the lower EBLV-1 dose died. By comparison, all of the EBLV-2 infected ferrets and four of five mice survived infection. All 20 infected ferrets seroconverted. Using sensitive molecular tools, the virus was detected in different tissues, but it could not be found in any saliva samples taken during the 84-day observation period.

Animals↗
PubMed2004

Rabies in red foxes (Vulpes vulpes) experimentally infected with European bat lyssavirus type 1.

The susceptibility of red foxes (Vulpes vulpes) to European bat lyssavirus type 1 (EBLV-1) infection was examined. Eight foxes were inoculated intramuscularly (i.m.) with 10(4.9) foci-forming units (FFU) (n = 4) and 10(5.1) FFU (n = 4) and observed for up to 90 days. All foxes showed manifestations of a neurologic disorder (e.g. seizures, myoclonus, agitation), starting as early as 5 days post-infection (p.i.). Subsequently, all animals showed improvement followed by one or more relapses. One fox was killed 3 days after it recovered, 26 days post-infection. Two other foxes were also killed 38 and 54 days post-infection after severe neurologic signs returned. All foxes developed a humoral immune response against EBLV-1 as determined in serum and brain tissues. However, no rabies virus antigen was detected in the brain, other tissues and secretions examined (e.g. salivary gland, saliva, tonsils, lungs) by using different standard diagnostic techniques [fluorescent antibody test, reverse transcription polymerase chain reaction (RT-PCR), rabies tissue culture inoculation test], with the exception of one fox in which EBLV-1 RNA was detected by RT-PCR in only the spinal cord. Brain tissues showed moderate to severe multifocal, mononuclear encephalomyelitis in the three foxes that were killed during the observation period, although no EBLV-1 virus was detectable in these tissues.

Animals↗