13,183 research outputs found

    The Visually Related Posterior Pretectal Nucleus in the Non-Percomorph Teleost Osteoglossum bicirrhosum Projects to the Hypothalamus

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    This study was done to elucidate the ancestral (plesiomorphic) condition for visual pathways to the hypothalamus in teleost fishes. Three patterns of pretectal organization can be discerned morphologically and histochemically in teleosts. Their taxonomic distribution suggests that the intermediately complex pattern (seen in most teleost groups) is ancestral to both the elaborate pattern (seen in percomorphs) and the simple pattern (seen in cyprinids). The pretectal nuclei involved can be demonstrated with acetylcholinesterase histochemistry selectively and reliably in different species of teleosts, suggesting that the same-named nuclei are homologous in representatives of the three different patterns. Whereas there are visual pathways to the hypothalamus in both the elaborate (percomorph) and the simple (cyprinid) patterns, different pretectal and hypothalamic nuclei are involved. Thus visual hypothalamic pathways in these two patterns would not appear to be homologous. In this study, circuitry within the third, i.e., the intermediately complex, pattern is investigated. It is demonstrated that visual pathways project via the pretectum to the hypothalamus in Osteoglossum bicirrhosum and that they are very similar to the visual pathways in the elaborate pattern. This suggests that the circuitry in the intermediately complex pattern, as represented by Osteoglossum, is plesiomorphic (evolutionarily primitive) and the circuitry in both the simple pattern (seen in cyprinids) and the elaborate pattern (seen in percomorphs) is apomorphic (evolutionarily derived) for teleosts

    Audition in vampire bats, Desmodus rotundus

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    1. Within the tonotopic organization of the inferior colliculus two frequency ranges are well represented: a frequency range within that of the echolocation signals from 50 to 100 kHz, and a frequency band below that of the echolocation sounds, from 10 to 35 kHz. The frequency range between these two bands, from about 40 to 50 kHz is distinctly underrepresented (Fig. 3B). 2. Units with BFs in the lower frequency range (10–25 kHz) were most sensitive with thresholds of -5 to -11 dB SPL, and units with BFs within the frequency range of the echolocation signals had minimal thresholds around 0 dB SPL (Fig. 1). 3. In the medial part of the rostral inferior colliculus units were encountered which preferentially or exclusively responded to noise stimuli. — Seven neurons were found which were only excited by human breathing noises and not by pure tones, frequency modulated signals or various noise bands. These neurons were considered as a subspeciality of the larger sample of noise-sensitive neurons. — The maximal auditory sensitivity in the frequency range below that of echolocation, and the conspicuous existence of noise and breathing-noise sensitive units in the inferior colliculus are discussed in context with the foraging behavior of vampire bats

    Catalogue of the ectoparasitic insects of the bats of Argentina

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    Taxonomy and distribution of the ectoparasitic insects of bats from Argentina, are reviewed. Seventeen species of Diptera (six of Nycteribiidae and eleven of Streblidae), six species of Siphonaptera (four ofIschnopsyllidae, one of Pulicidae, and one ofStephanocircidae), and seven species of Hemiptera (Polyctenidae) are known presently for Argentina. The information was obtained by reviewing the literature and collecting in the field between 1989 and 1998. The specimens collected in the field were compared with the type material deposited at the Field Museum of Natural History (CHNM).En este primer catalogo de insectos ectoparasitos de murcielagos de la Argentina, se ofrece informacion sobre taxonomia y distribucion. Se conocen actualmente en el pais 17 especies de Diptera (seis de Nycteribiidae yonce de Streblidae), seis de Siphonaptera (cuatro de Ischnopsyllidae, una de Pulicidae y una de Stephanocircidae) y siete especies de Hemiptera (Polyctenidae). Se consulto numerosa literatura sobre los distintos grupos y se reviso abundante material obtenido en viajes de campana realizados desde 1989 a 1998, a numerosas localidades de la Argentina. Se realizaron comparaciones con material tipo del Field Museum of Natural History (CHNM)

    Novel hemotropic mycoplasmas are widespread and genetically diverse in vampire bats

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    Bats (Order: Chiroptera) have been widely studied as reservoir hosts for viruses of concern for human and animal health. However, whether bats are equally competent hosts of non-viral pathogens such as bacteria remains an important open question. Here, we surveyed blood and saliva samples of vampire bats from Peru and Belize for hemotropic Mycoplasma spp. (hemoplasmas), bacteria that can cause inapparent infection or anemia in hosts. 16S rRNA gene amplification of blood showed 67% (150/223) of common vampire bats (Desmodus rotundus) were infected by hemoplasmas. Sequencing of the 16S rRNA gene amplicons revealed three novel genotypes that were phylogenetically related but not identical to hemoplasmas described from other (non-vampire) bat species, rodents, humans, and non-human primates. Hemoplasma prevalence in vampire bats was highest in non-reproductive and young individuals, did not differ by country, and was relatively stable over time (i.e., endemic). Metagenomics from pooled D. rotundus saliva from Peru detected non-hemotropic Mycoplasma species and hemoplasma genotypes phylogenetically similar to those identified in blood, providing indirect evidence for potential direct transmission of hemoplasmas through biting or social contacts. This study demonstrates vampire bats host several novel hemoplasmas and sheds light on risk factors for infection and basic transmission routes. Given the high frequency of direct contacts that arise when vampire bats feed on humans, domestic animals, and wildlife, the potential of these bacteria to be transmitted between species should be investigated in future work

    Extended-spectrum beta-lactamases-producing <i>Escherichia coli</i> in common vampire bats <i>Desmodus rotundus</i> and livestock in Peru

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    Antibiotic resistance mediated by bacterial production of extended‐spectrum beta‐lactamase (ESBL) is a global threat to public health. ESBL resistance is most commonly hospital‐acquired; however, infections acquired outside of hospital settings have raised concerns over the role of livestock and wildlife in the zoonotic spread of ESBL‐producing bacteria. Only limited data are available on the circulation of ESBL‐producing bacteria in animals. Here, we report ESBL‐producing Escherichia coli in wild common vampire bats Desmodus rotundus and livestock near Lima, Peru. Molecular analyses revealed that most of this resistance resulted from the expression of blaCTX‐M‐15 genes carried by plasmids, which are disseminating worldwide in hospital settings and have also been observed in healthy children of Peru. Multilocus sequence typing showed a diverse pool of E. coli strains carrying this resistance that were not always host species‐specific, suggesting sharing of strains between species or infection from a common source. This study shows widespread ESBL resistance in wild and domestic animals, supporting animal communities as a potential source of resistance. Future work is needed to elucidate the role of bats in the dissemination of antibiotic‐resistant strains of public health importance and to understand the origin of the observed resistance

    Identifikasi Senyawa Fenol Beberapa Aksesi Teki (Cyperus Rotundus L.) Serta Pengaruhnya terhadap Perkecambahan Biji Borreria Alata (Aubl.) DC.

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    Purple nutsedge (Cyperus rotundus L.) is one of the important weeds in the world because of its ability to suppress the production of crops and difficult to control. C. rotundus residues can suppress the growth of others weeds. The experiments were conducted to identify the phenolic compound of C. rotundus from six different accessions and to determine the allelopathic effects of C. rotundus extracts on germination of Borreria alata (Aubl.) DC. The identification of phenolic compound was done using extract from all part of mature C. rotundus taken from different accessions and was analyzed using GC-MS. Analysis of C. rotundus extracts on germination of B. alata was designed using completely randomized design with three replications. The treatments were extract of C. rotundus from different accessions (from Cikarawang-Darmaga, Babakan-Darmaga, Ciawi, Megamendung, Cisarua, and Cianjur) with different concentration, 0.75 kg L-1 and 1.5 kg L-1. The result showed that C. rotundus from six accession had phenolic compond with different amounts. Cianjur accesion contained the most phenol content such as 2-furanmethanol; 1,4-benzenediol; 2-methoxy-4-vinylphenol; phenol, 2,6-dimethoxy; syringic acid; and 3-hydroxybenzoic acid. Germination test showed that C. rotundus extracts from different accessions and concentration had the same inhibitory effect on germination of B. alata
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