Bat Brain Research Articles

Lipid composition and sphingolipid fatty acids of myelin in fruit bat brain

Myelin was isolated from the brain of adult fruit bats ( Rousettus aegyptiacus) in a discontinuous sucrose gradient. Cholesterol comprised 189.0 mol/100 mol lipid phosphorus, galactolipids 60.3 mol/100 mol phosphorus and plasmalogens 32.5 mol/100 mol phosphorus. Choline and ethanolamine glycerophosphatide were present in nearly equal amounts followed by serine glycerophosphatide, sphingomyelin and inositol glycerophosphatides. The fatty acid composition of sphingomyelin and non-hydroxy cerebroside was determined by gas-liquid chromatography. Fatty acids were mainly saturated or mono-unsaturated with a small percentage of polyunsaturated fatty acids present. The lipid composition and sphingolipid fatty acid distribution in bat myelin was fairly similar to that of other species.

Immunohistochemical localization of catecholamine-synthesizing enzymes and serotonin in the bat brain.

Monoaminergic neuron systems have been studied in frontal, sagittal and horizontal sections of the bat brain by the indirect immunofluorescent method using antibodies to tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH) and serotonin (5-HT).In general, the topographical distribution of monoaminergic neurons was found to be similar to that of the rat by Dahlstrom & Fuxe (3). However, some differences were found in the bat brain; namely the A3 group in the nucleus olivaris accessorius dorsalis and the A4 in the lateral part of the roof of the fourth ventricle were not observed.The 5-HT-immunofluorescent varicose fibers and terminals were widely spread throughout the brain, especially in the supra-ependymal parts of the ventricular walls, several cranial nerve nuclei such as V, VII, and Xth nerve nuclei, and the catecholaminergic cell groups (A1, A2, A6, A9, A10). In addition, both the dopaminergic neurons and 5-HT neurons were observed in the nucleus raphe dorsalis and the ventral tegmental area caudal to the interpeduncular nucleus.

Fatty acid composition of synaptosomes from normal and cobalamin deficient bat brain

1. 1. Synaptosomes were prepared from the brain of cobalamin deficient and cobalamin supplemented fruit bats ( Rousettus aegyptiacus) by a floatation method on a discontinuous sucrose gradient. 2. 2. There were no significant differences in fatty acid composition between the deficient and supplemented bats. 3. 3. The odd chain fatty acid 15:0 amounted to 0.2% of the total fatty acids in both groups. 4. 4. We conclude that the fatty acids of synaptosomal lipids are not a factor in the development of neural dysfunction in the cobalamin deficient fruit bat.

Evidence for separate echolocation and communication processing areas in the inferior colliculus of bats

Although acoustic signals are used by bats for both echolocation and for communication little is known about how communication signals are represented in the bat's brain. Recently we have obtained data which strongly suggest that the inferior colliculus of Mexican free-tailed bats (Tadarida brasiliensis mexicana) is functionally partitioned into two major subdivisions: a medial region having neurons specialized for processing echolocation signals and a lateral region having neurons that appear to be well suited for analyzing communication sounds. The features which distinguish the two regions are marked differences in tonotopic organization as well as in tuning and discharge properties. The tonotopic organization of the medial region is mammalian in design. The characteristic frequencies (CF) of neurons in this region increase in an orderly manner with depth and encompass the full compliment of frequencies in the echolocation sounds emitted by this species. The neurons in the medial region are very sensitive to brief frequency-modulated (FM) signals which mimic the natural orientation cries and exhibit fast recovery. In striking contrast, the tonotopy of the lateral portion of the colliculus is characterized by a relative constancy of CFs with depth. The CFs of neurons situated dorsally are 20-22 kHz and only increase to 24-26 kHz in the deepest parts of the lateral region. In addition, the majority of neurons are either unresponsive to brief FM signals or have very high thresholds for responding to these stimuli. A final feature is that many neurons have two frequencies of maximal sensitivity in their tuning curves. Such multiply tuned neurons were only found in the lateral region. Many of the communication sounds emitted by Mexican free-tailed bats have long constant frequency portions. The fundamental frequencies range from about 20-25 kHz and are rich in harmonics, features which correlate closely with the tuning features of neurons in the lateral region. [Supported by NIH Grants NS13276 and NS00367.]

DDT and DDE inhibition of bat brain ATPase activities

1. In vitro, bat brain ATPases were sensitive to DDT ‡ ‡ Abbreviations: DDT-1,1,1-trichloro-2,2- bis-chlorophenyl ethane; DDE-1,1-dichloro-2,2 bis chlorophenyl ethylene; EDTA-ethylenediaminetetracetic acid; NADH-nicotinamide adenine dinucleotide-reduced; PEP-phosphenolpyruvate; BSA-bovine serum albumin. and DDE at concentrations considerably below environmental levels. 2. DDT was a more effective ATPase inhibitor than was DDE by about three-fold. 3. Mitochondrial Mg 2+ APTase was more sensitive than Na +K + or non-mitochondrial Mg 2+ ATPase to both compounds.

The Sound-Centered Brain of the Bat

The Sound-Centered Brain of the Bat

Rapidly labelled RNA in the hibernating bat brain.

THE protein synthetic activity of the brain in hibernating animals is very low, compared with that in the control or artificially awakened animals1. The “rapidly labelled” RNA has been shown to exist in the brain by several workers2–5, although different findings are described concerning its ultracentrifugal profiles and biological activity. These facts led us to investigate the metabolism of the rapidly labelled RNA of the brain in hibernating animals.

A NEW VIRUS, "MML", ENZOOTIC IN BATS (MYOTIS LUCIFUGUS) OF MONTANA.

Summary A virus related antigenically to the group B arboviruses was isolated from a mouse bitten by a Myotis lucifugus collected in Western Montana, and was subsequently isolated from saliva, brain, and various other tissues of other bats of the same species. The virus produces fatal infection in adult white mice and cavies by intracerebral but not peripheral injection. Suckling mice are susceptible to peripheral inoculation. Rabbits and hamsters are not susceptible upon inoculation into the central nervous system. The virus is readily adaptable to 8-day-old chick embryos inoculated by the amniotic route and to KB cells in tissue culture. The smallest porosity gradacol membrane that permitted passage of the virus was 0.1 µ. It is sensitive to chloroform. Serologic tests indicated affinity but not identity to group B arboviruses: St. Louis, EBSG, Ilheus, Rio Bravo, and Powassan. Hemagglutination was produced with sucrose-acetone brain antigen at low titer only. Transmission of the virus by the bite of bats and presence of the virus in bat saliva may imply an adaptation of this virus to residence in and transmission by bats without necessary intervention of arthropod vectors. This virus is tentatively designated as Montana Myotis leukoencephalitis (MML) virus.

Bats as Carriers of Rabies

A BECENT report to the Legislative Council of Trinidad states that twenty persons died in South Trinidad between 1929 and 1931 of a disease considered by Dr. Hurst, of the Lister Institute, as due to the virus of rabies of a hitherto unknown type. The infection was not conveyed by dogs, as the last case of dog rabies was in 1914. The report suggests that bats may be concerned, and the Trinidad Guardian observes that since the issue of the report, Dr. Paman, the Government bacteriologist, says that he has found typical rabies symptoms in the brain of a Sangre Grande daylight bat—whatever species that may be. It is possible that a vampire, in attempting to suck the blood of a rabid dog, might be snapped at and escape with some injury sufficient for inoculation, when it would naturally bite and infect bats of its own and other species, the gregarious habits of bats, several different species of which often select the same retreat, being particularly favourable to the spread of such infection.