The American alligator (Alligator mississippiensis) is an aquatic diving reptile with a periodic breathing pattern. Previous work has identified pulmonary stretch receptors (PSR), both rapidly- and slowly-adapting, and intrapulmonary chemoreceptors (IPCs) that modulate breathing patterns in alligators. The purpose of the present study was to identify the effects of prolonged lung inflation and deflation (simulated dives) on PSR and/or IPC firing characteristics in the alligator. The effects of airway pressure, hypercapnia, and hypoxia on dynamic and static responses of pulmonary stretch receptors (PSR) were studied in juvenile alligators (mean mass = 246 g) at 24°C. Receptor activity appeared to be a mixture of slowly-adapting PSRs (SARs) and rapidly-adapting PSRs (RARs) with varying thresholds and degrees of adaptation, but no CO2 sensitivity. Dives were simulated in order to character receptor activity before, during, and after prolonged periods of lung inflation and deflation. Some stretch receptors showed a change in dynamic response, exhibiting inhibition for several breaths after 1 min of lung inflation, but were unaffected by prolonged deflation. For SAR, the post-dive inhibition was inhibited by CO2 and hypoxia alone. These airway stretch receptors may be involved in recovery of breathing patterns and lung volume during pre- and post-diving behavior and apneic periods in diving reptiles. These results suggest that inhibition of PSR firing following prolonged inflation may promote post-dive ventilation in alligators.

Striped bass larvae, native to the Shubenacadie River, catch invertebrates in darkness using mechanoreception via lateral line neuromasts. The neuromast total increased from 17 at first feeding (5 to 7 dph) to 135 by the juvenile stage (27 dph). A 5 mM neomycin dose ablated neuromasts, confirmed by fluorescent and confocal microscopy. In feeding trials, larvae with and without functional neuromasts were offered Artemia salina in darkness or light. To identify ontogenetic changes in feeding, experiments were repeated at 10, 13, 17, and 20 dph. In darkness, neomycin treated larvae caught fewer prey (~5 Artemia h-1 at all ages, p<0.05) than larvae with intact neuromasts (10 dph, 16 Artemia h-1; 20 dph, 72 Artemia h-1). In light, neomycin did not affect feeding, indicating no deleterious side-effects. Neomycin did not damage olfactory or taste cells judged by FM1-43FX and calretinin staining. The results support the contribution of mechanoreception to non-visual feeding. / Master's thesis

Using three-dimensional Schlieren-based videography, males of the freshwater alpine species Hesperodiaptomus shoshone (Wyoming) were found to follow both conspecific females and conspecific males, remaining 0.45 ± 0.13 cm (male) and 0.56 ± 0.13 cm (female) from the lead copepod for 0.91 ± 0.35 seconds (male) and 0.84 ± 0.46 seconds (female). Trail following is initiated when the male makes a rapid reorientation. Chemical pheromones either were not produced by the female or were not detected by the male because males would follow trail mimics composed of female-conditioned water. Using unconditioned water, males were found capable not only of following trail mimics but they showed a preference, quantified as a higher follow frequency, of trails running at speeds matching that of their female mate. Remarkably, the male copepods always followed upstream, micro-casting between the edges of the trail to remain on track. Trails flowing at speeds matching their mate’s swimming speed were followed for a longer period of time and at greater gross distance. As the flow speed of the trail mimic increased, the distance the copepod would advance would decrease until the threshold speed of 2.30 cm/sec at which it would not follow a trail and only station hold. Station holding has never been observed before for copepods and may represent an adaptive behavior to avoid being washed out of their resident alpine pond. At speeds greater than that evoking station holding, the stream seemed to push the copepod out of the flow even though the copepod would make repeated efforts to swim up the stream. This research revealed a behavior not documented before: instead of relying on discrete pulses of flow left by hopping copepods, this high alpine lake copepod followed smoothly swimming mates or continuously flowing thin streams, relying only on sensing hydrodynamic cues.

No description available.

Made available in DSpace on 2014-06-11T19:22:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-25Bitstream added on 2014-06-13T18:08:10Z : No. of bitstreams: 1 clavijoayala_ja_me_jabo_prot.pdf: 2110673 bytes, checksum: 81a603896afe42aa218b5fa3b86d612c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O pacu Piaractus mesopotamicus é uma das espécies de maior relevância na piscicultura de águas quentes no Brasil, destacando-se pela qualidade de sua carne e desempenho em sistemas de cultivo. Apesar do avanço no estudo da biologia, anatomia e morfologia da espécie, os aspectos relacionados com o desenvolvimento inicial do sistema sensorial são praticamente desconhecidos. Este estudo teve por objetivo descrever o desenvolvimento inicial de pacu Piaractus mesopotamicus, com ênfase na ontogenia das estruturas sensoriais. Para isto, amostras seriadas de embriões e larvas em desenvolvimento foram coletadas desde as 9 horas pós fertilização (hpf) até os 25 dias pós eclosão (dpe), e destinadas para análises morfológicas, histológicas e de microscopia eletrônica de varredura. O desenvolvimento embrionário da espécie é rápido, e cerca das 19 hpf(a 26,S ± O,SOC), as larvas eclodem num estado altricial (3,19 ± 0,04 mm comprimento notocordal- CN; 0,477 ± 0,061 mm3 volume do saco+ vitelino¬VSV). Na eclosão, o desenvolvimento do sistema sensorial é limitado: no epitélio olfatório observam-se neurônios sensoriais ciliados e neurônios sensoriais com microvilosidades; a presença de mecanorreceptores é restrita ao neuromasto ótico imaturo; o desenvolvimento do ouvido interno é incipiente, observa-se a presença de dois otólitos em cada cápsula ótica, mas a larva ainda não apresenta estabilidade na coluna de água nem coordenação nos seus movimentos; e os olhos apresentam-se com pouco ou nenhum pigmento, lente diferenciada e separada da córnea, e retina não estratificada No entanto, o desenvolvimento pós-embrionário do sistema sensorial é acelerado: a partir de 1 dpe o epitélio olfativo se encontra coberto por uma densa camada de cilios não sensoriais que se distribuem. tanto na vesícula... / Pacu, Piaractus mesopotamicus, is one of the species of major importance for warmwater fish farming in Brazil due to its meat quality and performance in culture systems. Despite the advances in the study of biology, anatomy and morphology of the species, the aspects related to the early development of the sensorial system are unknown. The aim of this study was to describe the initial development of pacu Piaractus mesopotamicus, with emphasis on the ontogeny of the sensorial structures. Embryos and larvae were serially sampled during development, from the 9 hours after fertilization (haf) to the 25 days after hatching (dah), and subjected to the morphology, histology and scanning electron microscopy analysis. The embryonic development of the species is fast: about 19 haf (at 26,5 ± 0,5°C), larvae hatch in an altricial state (3.19 ± 0.04 mm notochordal length - NL; 0.477 ± 0.061 mm3 yolk-sac volume - YSV). At hatching, the sensorial system development is limited: in the olfactory epithelium, there are ciliated sensorial neurons and microvillous sensorial neurons; the mechanoreceptors are restricted to the immature otic neuromast; the development of the inner ear is incipient, with two otoliths in each otic capsule, but larvae do not show neither stability in the water column or coordination of their movements; the eyes have no or few pigment, with lens differentiated and separated from the cornea, and non-stratified retina. However, the post-embryonic development of the sensorial system is accelerated: from the 1 st dah the olfactory epithelium is covered by a dense layer of non sensorial cilia, which are distributed in the olfactory vesicle and in the epithelium region around it; at 2,5-3 dah, the eyes are totally pigmented; from the 4th dah it is possible to identify solitary chemosensorial cells in the post-otical region;...(Complete abstract click electronic access below)

Orientadora: Maria Célia Portella / Banca: Irene Bastos Franceschini Vicentini / Banca: Marcos Antonio Cestarolli / Resumo: O pacu Piaractus mesopotamicus é uma das espécies de maior relevância na piscicultura de águas quentes no Brasil, destacando-se pela qualidade de sua carne e desempenho em sistemas de cultivo. Apesar do avanço no estudo da biologia, anatomia e morfologia da espécie, os aspectos relacionados com o desenvolvimento inicial do sistema sensorial são praticamente desconhecidos. Este estudo teve por objetivo descrever o desenvolvimento inicial de pacu Piaractus mesopotamicus, com ênfase na ontogenia das estruturas sensoriais. Para isto, amostras seriadas de embriões e larvas em desenvolvimento foram coletadas desde as 9 horas pós fertilização (hpf) até os 25 dias pós eclosão (dpe), e destinadas para análises morfológicas, histológicas e de microscopia eletrônica de varredura. O desenvolvimento embrionário da espécie é rápido, e cerca das 19 hpf(a 26,S ± O,SOC), as larvas eclodem num estado altricial (3,19 ± 0,04 mm comprimento notocordal- CN; 0,477 ± 0,061 mm3 volume do saco+ vitelino¬VSV). Na eclosão, o desenvolvimento do sistema sensorial é limitado: no epitélio olfatório observam-se neurônios sensoriais ciliados e neurônios sensoriais com microvilosidades; a presença de mecanorreceptores é restrita ao neuromasto ótico imaturo; o desenvolvimento do ouvido interno é incipiente, observa-se a presença de dois otólitos em cada cápsula ótica, mas a larva ainda não apresenta estabilidade na coluna de água nem coordenação nos seus movimentos; e os olhos apresentam-se com pouco ou nenhum pigmento, lente diferenciada e separada da córnea, e retina não estratificada No entanto, o desenvolvimento pós-embrionário do sistema sensorial é acelerado: a partir de 1 dpe o epitélio olfativo se encontra coberto por uma densa camada de cilios não sensoriais que se distribuem. tanto na vesícula...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Pacu, Piaractus mesopotamicus, is one of the species of major importance for warmwater fish farming in Brazil due to its meat quality and performance in culture systems. Despite the advances in the study of biology, anatomy and morphology of the species, the aspects related to the early development of the sensorial system are unknown. The aim of this study was to describe the initial development of pacu Piaractus mesopotamicus, with emphasis on the ontogeny of the sensorial structures. Embryos and larvae were serially sampled during development, from the 9 hours after fertilization (haf) to the 25 days after hatching (dah), and subjected to the morphology, histology and scanning electron microscopy analysis. The embryonic development of the species is fast: about 19 haf (at 26,5 ± 0,5°C), larvae hatch in an altricial state (3.19 ± 0.04 mm notochordal length - NL; 0.477 ± 0.061 mm3 yolk-sac volume - YSV). At hatching, the sensorial system development is limited: in the olfactory epithelium, there are ciliated sensorial neurons and microvillous sensorial neurons; the mechanoreceptors are restricted to the immature otic neuromast; the development of the inner ear is incipient, with two otoliths in each otic capsule, but larvae do not show neither stability in the water column or coordination of their movements; the eyes have no or few pigment, with lens differentiated and separated from the cornea, and non-stratified retina. However, the post-embryonic development of the sensorial system is accelerated: from the 1 st dah the olfactory epithelium is covered by a dense layer of non sensorial cilia, which are distributed in the olfactory vesicle and in the epithelium region around it; at 2,5-3 dah, the eyes are totally pigmented; from the 4th dah it is possible to identify solitary chemosensorial cells in the post-otical region;...(Complete abstract click electronic access below) / Mestre