Fluorescent granular pigment sprayed with 738 g/cm² (105 p.s.i .) for 5, 10, 20 second intervals was used to mark crayfish in a laboratory study. The pigment was retained by 100% of the unmolted crayfish 35 days after treatment and by 65% of the crayfish 56 days after treatment. Crayfish which were induced to molt after being sprayed generally lost the fluorescent pigment during the molt. Mortality, (2%), due to the marking procedures was minimal. / Master of Science

Acute effects of a pulsed external electric field (PEEF) at 20 V/cm and a d.c. EEF at 90 V/cm on light transmittance in an isolated compound crayfish nerve was measured. In a third series, the nerve was pre-treated with the Na+ channel blocker tetrodotoxin (TTX). A PEEF produced an irreversible increase in the variation of light transmittance in normal nerves but a reversible increase in TTX treated nerves. This data was statistically insignificant. The d.c. EEFs produced a reversible and statistically significant enhancement of variation in light transmittance in both untreated and TTX-treated nerves. The findings may be due to either (1) an alteration in the ion/fluid flux within the nerve or (2) a physical alteration of protein molecules in the membranes.

Title from first page of PDF document. Includes bibliographical references (p. 24-30).

Thesis (Ph. D.)--Brigham Young University. Dept. of Integrative Biology, 2006. / Includes bibliographical references (p. 122-130).

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Observations of animal distributions have revealed that population densities have tracked resource quality. Various models have been proposed to account for such “resource matching.” For example, the Ideal Free Distribution (Fretwell and Lucas 1970) model employs habitat selection rules which assume mobile animals evaluate available habitat patches and select the highest quality patch first. I examined movement patterns of northern crayfish (Orconectes virilis) in response to habitat patches of different quality to test this assumption. I found that animals were more likely to leave a low quality patch than a high quality patch even when there were no other patches available, suggesting that the quality of encountered resources plays a significant role in subsequent decisions about movement. However, many animals did not leave the first patch they encountered, even when better habitat existed elsewhere and was well within their ability to sample it. Finally, not all crayfish selected the best site they encountered. My studies demonstrate that the response to resources is complex, and IFDs and other distribution models may rely on overly simplified assumptions about habitat selection behavior.

Orientador: Carlos Roberto Ceron / Banca: Ana Maria Bonetti / Banca: Lilian Madi Ravazzi / Resumo: Os camarões do gênero Macrobrachium (Crustacea, Decapoda, Palaemonidae), encontrados em ambientes de água doce, são amplamente distribuídos pelas regiões tropicais e subtropicais do mundo, inclusive em locais próximos ao litoral. Algumas espécies desse gênero, como por exemplo M. rosenbergii, apresentam valor econômico, sendo cultivadas e comercializadas como alimento. Na região Noroeste do Estado de São Paulo, são encontradas as espécies classificadas como M. amazonicum e M. jelskii, as quais são espécies exóticas de camarões dulcícolas recentemente introduzidas e amplamente disseminadas em reservatórios de usinas hidrelétricas desta região. Essas espécies possuem hábitos crípticos e noturnos, sendo predadores de larvas de peixes e também presas de peixes adultos e outros organismos. M. amazonicum e M. jelskii apresentam grande similaridade interespecífica em termos de caracteres morfológicos, o que pode dificultar a classificação taxonômica desses organismos. O objetivo deste estudo foi conduzir análises morfométricas, ultraestruturais, isoenzimáticas e moleculares em M. amazonicum e M. jelskii, na tentativa de obter-se novos dados para distinguí-los. Os camarões foram coletados das populações dos reservatórios de Sales/SP e Mendonça/SP. As análises morfométricas englobaram as medidas do télson, dos espinhos caudais internos e do rostro. As análises por microscopia eletrônica de varredura foram realizadas nas estruturas do télson, nos espinhos caudais internos e no apêndice masculino. As análises isoenzimáticas, realizadas por eletroforese em gel de poliacrilamida, abrangeram as enzimas álcool desidrogenase, octanol desidrogenase, glicose-6-fosfato desidrogenase, lactato desidrogenase, amilase e esterases do hepatopâncreas e tecido muscular. Análises moleculares envolveram a amplificação do espaçador intergênico interno ITS-1 (Internal Transcribed Spacer 1) do rDNA. Os fragmentos ... / Abstract: Prawns of the genus Macrobrachium (Crustacea, Decapoda, Palaemonidae) can be found in freshwater environments, widely distributed throughout tropical and subtropical regions of the world, including regions near the coast. Some species of this genus, for example Macrobrachium rosenbergii, present economic value, which are reared and traded as food. In the northwest region of São Paulo State two exotic freshwater prawn species are found, classified as M. amazonicum and M. jelskii, which were recently introduced to the aquatic reservoirs of hydroelectric power plants and then, disseminated throughout reservoirs in this region of the State. These species have cryptic and overnight habits, being predators of fish larvae and also being prey to adult fishes and other organisms. M. amazonicum and M. jelskii present high rates of interspecific similarity in terms of morphological characters, which are generally used to distinguish them, what may induce mistakes in taxonomic identification. The objective of this study was to conduct morphometric, ultrastructural, isoenzymatic and molecular analyses of M. amazonicum and M. jelskii, in order to obtain more data about their differentiation. The prawns were collected in reservoirs of Sales/SP and Mendonça/SP. Morphometric analyses were performed involving the structures of telsons, internal caudal spines and rostrums. Scanning electron microscopy analyses were performed on structures of telsons, internal caudal spines and male appendices. Isoenzymatic analyses by polyacrylamide gel electrophoresis included the enzymes alcohol dehydrogenase, octanol dehydrogenase, glucose-6-phophate dehydrogenase, lactate dehydrogenase, amylase and esterases of hepatopancreas and muscle tissue. Molecular analyses were performed by amplification and sequencing of ITS-1(Internal Transcribed Spacer 1) intergenic spacer from rDNA. The amplificated fragments were used for analyzing length polymorphism restriction fragments ... / Mestre

Os lagostins de água doce sulamericanos (Família Parastacidae) são representados por três gêneros: Parastacus Huxley, 1879, Samastacus Riek, 1971 and Virilastacus Hobbs, 1991. Esse grupo é distribuído no Sul do Brasil (Rio Grande do Sul and Santa Catarina), Uruguai, Argentina e Chile. Os objetivos dessa tese foram revisar a taxonomia do gênero Parastacus e investigar a sua monofilia e relações filogenéticas entre suas espécies e entre os outros gêneros sulamericanos. Para esse propósito, várias coleções e museus ao redor do mundo foram analisados (Brasil, Argentina, Uruguai, Chile, Estados Unidos, Alemanha, Holanda, Inglaterra e França) em adição a coletas realizadas entre Março de 2013 a Setembro de 2016. Os espécimes foram analisados em estereomicroscópio e os desenhos foram preparados com auxílio de camara lucida. Para as análises genéticas, uma abordagem multigênica foi utilizada com dois marcadores mitocondriais (Cox1 e 16S) e um nuclear (28S). A análise filogenética foi realizada por Inferência Bayesiana e a distância genética p também foi calculada. Adicionalmente, o risco de extinção foi assessado para algumas espécies de acordo com o sub-critério B1 da IUCN que leva em consideração a estimativa da Área de Extenção de Ocorrência. Oito espécies foram redescritas: Parastacus brasiliensis (von Martens, 1869), P. defossus Faxon, 1898, P. laevigatus Buckup & Rossi, 1980, P. pilimanus (Von Martens, 1869), P. pugnax (Poepigg, 1835), P. promatensis Fontoura & Conter, 2008 e P. varicosus Faxon, 1898. Um novo gênero foi proposto para alocar a espécie P. nicoleti (Philippi, 1882) que também foi redescrita. Treze novas espécies foram descritas. Assim como, chaves de identificação, descrições, diagnoses, sinonímias e mapas de distribuição foram providos. As árvores filogenéticas resultantes corroboraram com a monofilia de Parastacus e do clado sulamericano, além de dar suporte para o estabelecimento de um novo gênero e novas espécies. Com essa tese, o aumento da riqueza específica para Parastacus é de mais de 150% e as novas informações sobre habitat e distribuição trarão suporte para futuros estudos de conservação e manejo. / South American freshwater crayfish (Family Parastacidae) are represented by three genera: Parastacus Huxley, 1879, Samastacus Riek, 1971 and Virilastacus Hobbs, 1991. This group is distributed in Southern Brazil (Rio Grande do Sul and Santa Catarina), Uruguay, Argentina and Chile. The goals of this thesis is to review the taxonomy of the genus Parastacus and to investigate the monophyly and phylogenetic relationships within Parastacus and among South American crayfish genera. For this purpose, several collections and museums around the world were analyzed (Brazil, Argentina, Uruguay, Chile, United States of America, Germany, Netherlands, England, and France) in addition to collectings carried out from March 2013 to September 2016. Specimens were analyzed under a stereomicroscope and drawings were prepared with the aid of a camara lucida. For genetic analysis, a multigenic approach was used with two mitochondrial (Cox1 and 16S) and one nuclear (28S) markers. Phylogenetic analysis were performed with Bayesian Inference and genetic p-distances were also calculated. In addition, the extinction risk was assessed according to the sub-criterion B1 of IUCN that estimates the Extent of Occurrence (EOO) for some species. Eight species are redescribed: Parastacus brasiliensis (von Martens, 1869), P. defossus Faxon, 1898, P. laevigatus Buckup & Rossi, 1980, P. pilimanus (Von Martens, 1869), P. pugnax (Poepigg, 1835), P. promatensis Fontoura & Conter, 2008 and P. varicosus Faxon, 1898. A new genus is proposed to encompass the species P. nicoleti (Philippi, 1882) and this species is also redescribed. In addition, 13 new species are described. Identification keys, descriptions, diagnoses, synonymies and distribution maps of the genera and species are provided. Phylogenetic trees corroborated the monophyly of Parastacus and the South American crayfish clade, and give support for the establishment of a new genus and new species. With this thesis, the increase in specific richness for Parastacus is more than 150% and new information about habitat and distribution will bring support for future conservation and management studies.

Inhibitory neurons exert control the expression of many aspects of behaviour by regulating the effectiveness of excitatory neural function. By comparison with excitatory neural systems, relatively little is known about the development of inhibitory neurons and the influence which these neurons exert on the development of other neural systems. Two issues which relate to the development of inhibitory neurons are of particular interest. First, a paradox arises when inhibitory neurons are considered in terms of modern models of synaptic development which involve activity-dependent mechanisms of synaptic plasticity. Second, there is some evidence that inhibitory neurotransmitters may act in a special trophic manner during the early development of nervous systems. Investigations of these issues would be greatly facilitated in a neural system in which it was possible to experimentally control aspects of the development of individual pre- and postsynaptic cells. The aim of the results presented in this thesis was to characterise the normal development of one such system: the GABAergic inhibitory system of the Australian freshwater crayfish, Cherax destructor. The ontogeny of the inhibitory neurotransmitter GABA across the embryonic period of 30% to 100% development was investigated using immunohistochemical techniques. GABA-like immunoreactive cells and fibres were first detected in the embryonic brain region. The expression of GABA-like immunoreactivity progressed along a rostro-caudal gradient, with GABA-like immunoreactive cells being detected in the most anterior thoracic ganglia at 45% development and in all ganglia by 65% development. GABA-like immunoreactive fibres were evident in peripheral nerves as early as 55% development and ramified extensively throughout the neuropil of the nervous system by 65% development. By contrast, immunoreactivity to the primary excitatory neurotransmitter, glutamate, was not detected until 60-65% development. Glutamate-like immunoreactivity at 60-65% development was evident only in the form of punctate staining in the midline of the ventral nerve cord. Cell body staining was observed only at 90% development and was restricted to only a few cells on the periphery of the ventral nerve cord. Radio-labelled ligand binding methods and autoradiography were used to study the expression of putative GABA receptors in the Cherax embryos from 30% to 100% development. Specific binding was evident in the earliest embryos studies at 30% development. There was an initial increase in binding from 30% to 40% development, followed by a dramatic drop to almost zero binding at 50-55% development. This was followed by a gradual increase in binding levels with age, reaching a plateau at 85% development. Preliminary pharmacological evaluation of binding indicated that at least three GABA receptor types were expressed during embryonic development. Methods for culturing, dissociated neural tissues explanted form Cherax embryos at 85% development were established. The success of cultures was demonstrated by neurite extension, and neuronal networks in which neurons appeared to form connections with other neurons and with explanted muscle cells after two days in culture. Immunohistochemical studies demonstrated that some explanted neurons expressed GABA-like immunoreactivity within two days of explanting. These studies have provided a comprehensive description of the development of GABAergic neurons and their receptors in Cherax destructor embryos. The very early expression of GABA-like immunoreactivity, coupled with the early onset of specific GABA binding, strongly indicates that the GABAergic neurons are functional and able to exert an effect on other cells during much of the period of nervous system development in crayfish embryos. These results support the hypothesis that inhibitory neurons may play an important role as regulators of the overall process of assembly and maturation of the nervous system and provide a substantial basis for future experimental studies in which the specific action of inhibitory neurons on the development of discrete components of the crayfish nervous system may be investigated.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 130-137). Also available on the Internet.