Effect of tannic acid on iron absorption in straw‐colored fruit bats (Eidolon helvum)

Excessive absorption and subsequent storage of dietary iron has been found in a variety of captively held birds and mammals, including fruit bats. It is thought that feeding a diet that is low in iron can prevent the onset of this disease; however, manufacturing a diet with commonly available foodstuffs that contains a sufficiently low iron concentration is difficult. An alternative is to feed captive animals that may be susceptible to this disease potential iron chelators such as tannins that may bind to iron and block its absorption. Using stable isotope methods established in humans, we measured iron bioavailability in straw‐colored fruit bats (Eidolon helvum) and tested whether tannic acid significantly reduced the extent of iron absorption. Regardless of dose, tannic acid significantly reduced iron absorption (by 40%) and in the absence of tannic acid, iron absorption was extensive in this species (up to 30%), more so than in humans. Species susceptible to iron storage disease may efficiently absorb iron in the gut regardless of iron status, and supplementing these species with tannic acid in captivity may provide an alternative or additional means of preventing the development of this disease. Zoo Biol 29:335–343, 2010. © 2009 Wiley‐Liss, Inc.     

Presence of rhodanese in the cytosolic fraction of the fruit bat (Eidolon helvum) liver

Rhodanese was isolated and purified from the cytosolic fraction of liver tissue homogenate of the fruit bat, Eidolon helvum, by using ammonium sulphate precipitation and CM-Sephadex C-50 ion exchange chromatography. The specific activity was increased 130-fold with a 53% recovery. The K(m) values for KCN and Na(2)S(2)O(3) as substrates were 13.5 +/- 2.2mM and 19.5 +/- 0.7 mM, respectively. The apparent molecular weight was estimated by gel filtration on a Sephadex G-100 column to be 36,000 Da. The optimal activity was found at a high pH (pH 9.0) and the temperature optimum was 35 degrees C. An Arrhenius plot of the heat stability data consisted of two linear segments with a break occurring at 35 degrees C. The apparent activation energy values from these slopes were 11.5 kcal/mol and 76.6 kcal/mol. Inhibition studies on the enzyme with a number of cations showed that Mg(2+), Mn(2+), Ca(2+), and Co(2+) did not affect the activity of the enzyme, but Hg(2+) and Ba(2+) inhibited the enzyme.     

Isolation ofLecythophora mutabilis andWangiella dermatitidis from the fruit eating bat,Eidolon helvum

Lecythophora mutabilis was isolated from the lungs of 3 and from the liver of 2 bats,Eidolon helvum a fruit eating species.Wangiella dermatitidis was recovered from the liver of 2 bats of the same species. The isolates were pathogenic for laboratory mice when injected by subcutaneous, intraperitoneal and intravenous routes.W. dermatitidis was neurotropic in the mice injected intravenously.     

Isolation and properties of creatine kinase from the breast muscle of tropical fruit bat, Eidolon helvum (Kerr)

Creatine kinase, from fruit bat breast muscle, has been purified to homogeneity. The mol. wt of the enzyme was estimated to be about 78,000-80,000 with two subunits of 42,500. There are nine thiol residues/mol of the enzyme and two of these react readily with DTNB leading to total inactivation of the enzyme. The metal ion specificity was in order Mg2+ greater than Zn2+ greater than Co2+. Initial velocity and product inhibition studies of the reverse reaction are consistent with sequential reaction but of either rapid equilibrium random or ordered type.     

Analysis of asymmetries in the African fruit bats Eidolon helvum and Rousettus egyptiacus (Mammalia: Megachiroptera) from the islands of the Gulf of Guinea. I. Variance and size components of bilateral variation

A set of cranial characters was examined in the fruit bats Rousettus egyptiacus and Eidolon helvum to compare trends and relative importance of major components of bilateral morphometric variation, and their relationship with character size. Using two‐way, sides‐by‐individuals ANOVA , four components of variation were estimated for each bilateral variable: individual variation (I), directional asymmetry (DA), non‐directional asymmetry (NDA) and measurement error (E). Both species exhibit similar major trends of variation in asymmetry across characters, as shown by principal component analysis, using variance components as variables. Degree of interspecific congruence among characters was confirmed by a two‐way ANOVA with species and variance components as fixed factors. Congruence of asymmetry patterns between species suggests that the concept of population asymmetry parameter (PAP) could be extended to higher hierarchies. PAPs above the species level may result from common mechanisms or similar developmental constraints acting on species’ buffering capacities and morphological integration processes.     

Isolation and properties of cytoplasmic alpha-glycerol 3-phosphate dehydrogenase from the pectoral muscle of the fruit bat,Eidolon helvum

Cytoplasmic alpha-glycerol-3-phosphate dehydrogenase from fruit-bat-breast muscle was purified by ion-exchange and affinity chromatography. The specific activity of the purified enzyme was approximately 120 units/mg of protein. The apparent molecular weight of the native enzyme, as determined by gel filtration on Sephadex G-100 was 59,500 +/- 650 daltons; its subunit size was estimated to be 35,700 +/- 140 by SDS-polyacrylamide gel electrophoresis. The true Michaelis-Menten constants for all substrates at pH 7.5 were 3.9 +/- 0.7 mM, 0.65 +/- 0.05 mM, 0.26 +/- 0.06 mM, and 0.005 +/- 0.0004 mM for L-glycerol-3-phosphate, NAD(+), DHAP, and NADH, respectively. The true Michaelis-Menten constants at pH 10.0 were 2.30 +/- 0.21 mM and 0.20 +/- 0.01 mM for L-glycerol-3-phosphate and NAD(+), respectively. The turnover number, k(cat), of the forward reaction was 1.9 +/- 0.2 x 10(4)s(-1). The treatment of the enzyme with 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) under denaturing conditions indicated that there were a total of eight cysteine residues, while only two of these residues were reactive towards DTNB in the native enzyme. The overall results of the in vitro experiments suggest that alpha-glycerol-3-phosphate dehydrogenase of the fruit bat preferentially catalyses the reduction of dihydroxyacetone phosphate to glycerol-3-phosphate.     

Experimental rabies virus infection of big brown bats (Eptesicus fuscus)

A captive colony of adult Big Brown Bats (Eptesicus fuscus) was experimentally infected with a rabies virus (RABV) variant isolated from the salivary glands of a naturally infected Big Brown Bat and passaged once through murine neuroblastoma cell culture. Bats were divided into 11 groups, which were composed of one to three noninfected and one to three infected individuals each. Twenty of 38 animals were infected intramuscularly into both left and right masseter muscles; they received a total of 10(3.2) median mouse intracerebral lethal dose (MICLD50) of Big Brown Bat RABV variant. Experimental outcome after viral exposure was followed in the bats for 140 days postinoculation (PI). Of 20 infected bats, 16 developed clinical rabies, and the mean incubation period was 24 days (range: 13-52 days). Three infected bats never seroconverted and succumbed early to infection (13 days). Four infected bats that survived until the end of the experiment without any signs of disease maintained detectable antibody titers until the third month PI, peaking between days 13 and 43, and consequent drop-off below the threshold for detection occurred by day 140. Limited excretion of virus in saliva of infected bats during the clinical course of disease was observed in two individuals on days 13 and 15 PI (<24 hr prior to onset of clinical illness). No bat-to-bat transmission of RABV to noninfected bats was detected.     

Detection of rabies virus antibodies in Brazilian free-ranging wild carnivores

Rabies virus is a pathogen of major concern in free-ranging wild carnivores in several regions of the world, but little is known about its circulation in Brazilian wild carnivores. Sera from 211 free-ranging wild carnivores, captured from 2000 to 2006 in four locations of two Brazilian biomes (Pantanal and Cerrado), were tested for rabies antibodies. Twenty-six individuals (12.3%) had neutralizing antibody titers ≥0.10 IU/ml. The four sampled locations had antibody-positive animals, suggesting that Rabies virus circulates in all of these regions. Results underscore the risk posed by rabies for conservation of Brazilian carnivores and the possibility of the animals acting as reservoirs for the Rabies virus.     

Histology,ultrastructure, and seasonal variations in the bulbourethral gland of the African straw-colored fruit bat Eidolon helvum

We studied the morphological characteristics and seasonal changes of the bulbourethral gland of Eidolon helvum in a typical African tropical environment. Forty-eight bulbourethral glands were examined using gross anatomical, histological, histochemical, and ultrastructural techniques during the early rainy, late rainy, and peak dry seasons. The pear-shaped bilateral bulbourethral glands were located extra-abdominally in the inguinal region. Trabeculae from the capsule divided the parenchyma into numerous lobules of tubuloalveolar glandular acini. The mucosa was covered by a simple columnar epithelium consisting up of principal secretory cells, columnar dense cells and basal cells, which were progressively pronounced during the dry season. The principal cells contained eosinophilic granules, which were PAS positive while the dense cells did not show affinity for the stains. The mean gross weights, acini diameters, and epithelial heights were greater during the rainy season than the dry season. Ultrastructural evaluation showed that the cytoplasm of the principal cells contained well-developed Golgi complexes, rough endoplasmic reticulum, mitochondria, and secretory vesicles of varying electron densities and sizes. The secretory vesicles were numerous during the early rainy season, decreased during the late rainy season and were scanty during the peak dry season. The simple columnar epithelium observed during the rainy season was replaced by an undefined stratified epithelium during the dry season, and this was associated with cellular degenerations and regenerations. In conclusion, E. helvum has a typical mammalian bulbourethral gland, with a unique cell type, the dense cell whose functions are not well-understood. The gland exhibits cyclical seasonal variation in structure and secretory activity; being active during the early rainy season (breeding season), and showing the lowest activity during the dry season (non-breeding season). Glandular epithelial cell renewal occurs during the dry season in preparation for the next breeding season.     

Analysis of asymmetries in the African fruit bats Eidolon helvum and Rousettus egyptiacus (Mammalia: Megachiroptera) from the islands of the Gulf of Guinea. II. Integration and levels of multivariate fluctuating asymmetry across a geographical range

Using a set of cranial morphometric characters, trends of variation in multivariate fluctuating asymmetry were evaluated and compared in populations of African fruit bats Rousettus egyptiacus and Eidolon helvum from the Gulf of Guinea islands, and the adjacent mainland. Levels of asymmetry were compared across populations and species, and significant differences were found in both comparisons. Differences coincided with species‐specific patterns of morphological and genetic differentiation. Concordance of correlation matrices of asymmetry was also compared. Results were significant; concordance is hypothesized to be a by‐product of developmental processes that produce the ‘fox‐like’ morphology shared by these species. Consistency of asymmetry patterns suggests that the developmental pathway producing it is highly canalized. A prediction of the above hypothesis is that a radical change in the ‘fox‐like’ structural pattern would result in breakage of the asymmetry parameter associated with it.     

A comparative study of rabies virus isolates from hematophagous bats in Brazil

The Brazilian chiropteran fauna consists of 167 species; of which, three are hematophagous: the common vampire bat (Desmodus rotundus), the white-winged vampire bat (Diaemus youngi), and the hairy-legged vampire bat (Diphylla ecaudata). The aim of this study was to describe the isolation of Rabies virus from common and hairy-legged vampire bats and to report the first comparative antigenic and genetic studies of isolates from these bats. Antigenic and genetic typing of both isolates identified them as antigenic variant 3 (AgV3), the variant frequently isolated from common vampire bats. Phylogenetic analysis showed 99.3% identity between the isolates. This is the first time since 1934 that Rabies virus has been isolated from hairy-legged vampire bats in Brazil. Our analysis provides evidence that the existence of rabies-positive isolates from hairy-legged vampire bats may be the result of an interspecific rabies transmission event from common vampire bats and suggests that roost cohabitation may occur.     

Morphological and allozyme variation of Eidolon helvum (Mammalia: Megachiroptera) in the islands of the Gulf of Guinea

Morphological and genetic variation is evaluated among populations of the bat, Eidolon helvum , in the islands of the Gulf of Guinea (Central Africa). The populations from the islands of Bioko, Principe, and Sao Tome do not show significant phenetic differentiation, although a trend towards a reduction of size is found in the latter two islands. The low genetic distances between populations, as well as their values of Wright's fixation indexes, suggest that gene flow has hampered differentiation on these islands. In contrast, the population from Annobon, the smallest and farthermost island, shows remarkable morphological and genetic differentiation. On the mainland, E. helvum displays unique migratory and dispersal behaviours, but migratory behaviour was not found in any of the island populations. The combination of selective forces in harsher oceanic environments and restricted gene flow among populations appears to have favoured the high degree of morphological differentiation of E. helvum on Annobon. Due to the extended length of the dry season in Annobon, an earlier achievement of sexual maturity–and consequently smaller size—may be advantageous in the absence of migration. The differentiation is more marked among females, which also suggests that selection may be linked to the reproductive pattern. The population of the island of Annobon is herein described as a new subspecies, Eidolon helvum annobonensis subsp. nov.     

中国蝙蝠携带狂犬病毒研究进展

狂犬病(Rabies),是由狂犬病毒(Rabies Virus,RV)引起的人和所有哺乳动物的急性致死性中枢神经系统的自然疫源性疾病.该病呈全球性分布、病死率高,引起学者们对病原鉴定、免疫防治等的广泛研究,并取得了重大进展.研究表明,蝙蝠是多种人兽共患疾病病毒的储存宿主,因此,蝙蝠携带狂犬病毒的调查研究引起广大学者们的广泛关注,蝙蝠在我国物种丰富,分布广泛,作为很多病毒的可能自然宿主,其感染携带RV的流行病学数据尚未可知.本文对我国蝙蝠的种类、分布以及蝙蝠作为狂犬病毒自然宿主的研究进展进行了综述,为广大学者的进一步相关研究提供参考依据.