Made available in DSpace on 2014-06-11T19:30:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-28Bitstream added on 2014-06-13T19:19:24Z : No. of bitstreams: 1 campos_cfm_dr_jabo.pdf: 893698 bytes, checksum: 797044f736c6cdcb2636bfe07a8e23cf (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho são apresentados dados de abundância média, prevalência e intensidade média de parasitismo em trinta e quatro espécimes de Pseudoplatystoma fasciatum, popularmente conhecidos como cacharas, capturados nos meses de março, setembro e novembro de 2003, outubro de 2004 e 2005, com tarrafas e redes de espera no rio Aquidauana. Todos os indivíduos amostrados encontravam-se parasitados. Dezenove espécies de parasitos foram identificadas, sendo sete cestodas proteocefalídeos, três monogeneas, um digenea, três nematodas, um acantocéfalo, um crustáceo, um pentastomídeo e duas espécies de mixosporídeos. As espécies de cestóides, Harriscolex kaparari e Megathylacus travassosi são registradas pela primeira vez para P. fasciatum capturados no rio Aquidauana. Os monogeneas foram os endohelmintos que apresentaram maior prevalência (100 %), seguidos pelos cestodas (91,18 %) e nematodas (58,82 %). / In this work are presented mean abundance, prevalence and mean intensity of infection in 34 specimens of Pseudoplatystoma fasciatum, commonly called cacharas. Fish were captured in Aquidauana river in March, September and November 2003, October 2004 and 2005, with nets in the Aquidauana river. All analyzed fish were infected. Nineteen species of parasites were collected, seven of proteocephalid cestodes, three of monogeneans, one of digeneans, three of nematodes, one of acanthocephalan, one of crustacean, one of pentastomid and two species of myxosporeans. The first record of Harriscolex kaparari and Megathylacus travassosi in P. fasciatum in the Aquidauana river was observed. Monogeneans were showed the highest prevalence, followed by cestodes (91.18 %) and nematodes (58.82 %).

No description available.

Crustaceans, the most abundant group of organisms that make up zooplankton, form a critical link in the food web between primary-producing phytoplankton and planktivorous fish. Examining this link is essential in order to effectively estimate the amount of energy available to higher trophic levels. The most appropriate currency for tracking energy flow through these food webs is to measure production, or the amount of new biomass generated over a given period of time. Although measurements of primary productivity are routinely made in oceanographic studies, estimates of secondary productivity are rare due to their historical reliance on time-consuming methods. The overall objective of this thesis was to determine the factors influencing temporal variations in community-level crustacean productivity. A simplified lab experiment was used to establish a relationship between diet and chitobiase-based estimates of copepod productivity in response to single versus mixed species phytoplankton diets. In addition, the relationships between primary productivity and chitobiase-based productivity for the entire crustacean zooplankton community were examined over two years in Saanich Inlet, British Columbia, Canada. Lastly, this work determined the abiotic and biotic factors most strongly influencing crustacean productivity in the tropical Guanabara Bay, Rio de Janeiro, Brazil, dominated by the microbial loop. Results from this work show that: (i) copepod populations fed a poor food item take longer to develop through early stages, have lower daily growth rates, and exhibit lower productivity than those fed a good quality food item; (ii) important variations in crustacean productivity are missed when biomass estimates, alone, are used to represent food available to higher trophic levels; (iii) relationships between primary productivity and crustacean productivity can vary interannually and are not necessarily controlled by bottom-up processes; (iv) substantial interannual variations in trophic transfer efficiency (TTE) occur even if average TTE is the same across years; and (v) community-level crustacean productivity in tropical regions dominated by the microbial food loop can be as high as, if not higher than, productivity measured in temperate regions. Ultimately, this work provides insight into how accurate productivity estimates can improve our understanding of zooplankton dynamics in both laboratory and field settings in marine ecosystems worldwide. / Graduate

A homeostase do cálcio possui um papel central no funcionamento dos tecidos e células animais e torna-se, então, fundamental o entendimento dos mecanismos celulares de transporte de Ca2+ transmembrânico, e para isso, os crustáceos têm sido utilizados como modelo de estudo. Caranguejos terrestres e semi-terrestres, devido ao acesso limitado ao meio líquido desenvolveram mecanismos fisiológicos para a conservação de Ca2+ (em gastrólitos, hemolinfa e hepatopâncreas), sendo que os crustáceos apresentam quatro tecidos especializados para troca bi-direcional específica de Ca2+: (i) brânquias, (ii) epitélio do sistema digestivo, (iii) glândulas antenais e (iv) a camada da hipoderme da cutícula (não analizado no presente projeto). Nesses tecidos, a entrada de Ca2+ através de membranas apicais envolve o trocador de Ca2+/nNa+ (nH+) e um canal de Ca2+; os trocadores basolaterais, por outro lado, envolvem (i) o trocador de Ca2+/Na+ (ii) uma bomba de Ca2+- ATPase, e (iii) um canal de cálcio inibido por verapamil. Estudou-se aqui a ação conjugada de inibidores (amiloride e verapamil) e a ação indireta da ouabaína (inibidor da Na+/K+ ATPase) sobre a tomada de Ca2+, visando testar a necessidade de um gradiente de Na+ para o transporte secundário de Ca2+ em células isoladas de brânquias, glândulas antenais e hepatopâncreas preparadas a partir de animais em fase de inter-muda e pós-muda. Nos caranguejos utilizados no presente projeto (Superfamília Grapsoidea), os quais apresentam diferentes níveis de terrestrialidade: (A) Casmagnathus granulatus T2, (B) Sesarma rectum T3 e (C) Goniopsis cruentata T3., os inibidores amiloride (12,7 mM), verapamil (40 mM), e amiloride + verapamil conjugados, promoveram tendências à redução no transporte de Ca2+. O uso do inibidor ouabaína (17,1 mM), sugere a necessidade de um gradiente de Na+ para o transporte secundário de Ca2+. Os resultados obtidos comprovaram também a relação entre o nível de terrestrialidade e as adaptações fisiológicas em relação à homeostase do Ca2+ somente em hepatopâncreas, enquanto que a glândula antenal parece não exercer papel relevante na homeostase do Ca2+ em caranguejos semi-terrestres. / Calcium homeostasis possess a central role on animal cells and tissues and the understanding of transepithelial Ca2+ transport mechanisms becomes fundamental, and crustaceans have been used as study model. Since terrestrial and semi-terrestrial crabs have limited access to water, they have evolved physiological mechanisms in order to conserve Ca2+ (in gastroliths, hemolymph and hepatopancreas), and crustacean have shown four specialized tissues for specific bidirectional Ca2+ exchange: (i) gills, (ii) the gut epithelia, (iii) antennal glands e (iv) the layer of cuticle hypodermis (not analyzed in this project). In these tissues, the apical Ca2+ uptake involves a Ca2+/nNa+ (nH+) exchanger and a Ca2+ channel; in contrast, basolateral exchangers may involve: (i) a Na+/Ca2+ exchanger (ii) a Ca2+ ATPase, and (iii) a verapamil-inhibited Ca2+ channel. The objective of this project was to study the action of conjugated inhibitors (amiloride and verapamil) and ouabain (Na+/K + ATPase inhibitor) on Ca2+ uptake, to show the necessity of a Na+ gradient for the secondary Ca2+ transport in isolated gills, antennal glands and hepatopancreatic cells from intermoult and postmoult animals. The crabs used in this project (Grapsoidea Superfamily), present different levels of terrestrial adaptations: (a) Casmagnathus granulatus T2, (b) Sesarma rectum T3 and (c) Goniopsis cruentata T3. The inhibitors amiloride (12,7 mM), verapamil (40 mM), and amiloride + verapamil used in this project promoted a tendency to reduce Ca2+ transport. The results on ouabain inhibitor (17.1 mM) suggests the necessity of a Na+ gradient for secondary Ca2+ transport,. The results also suggest a relationship between level of terrestrial adaptation and physiological responses related to Ca2+ homeostasis in hepatopancreas, while the antennal gland does not seem to have a relevant role on Ca2+ homeostasis in semi-terrestrial crabs.

Neural circuit flexibility is fundamental to the production of adaptable behaviors. Invertebrate models offer relatively simple networks consisting of large, identifiable neurons that are useful for investigating the electrophysiological properties that contribute to circuit output. In particular, central pattern generating circuits within the crustacean stomatogastric nervous system have been well characterized with regard to their synaptic connectivities, cellular properties, and response to modulatory influences. Monoaminergic modulation is essential for the production of adaptable circuit output in most species. Monoamines, such as dopamine and serotonin, signal via metabotropic receptors, which activate intracellular signaling cascades. Many of the neuronal and network targets of monoaminergic modulation in the crustacean stomatogastric nervous system are known, but nothing is known of the signal transduction cascades that mediate the biophysical response. This work represents a thorough characterization of monoaminergic receptors in the crustacean stomatogastric nervous system. We took advantage of the close phylogenetic relationship between crustaceans and insects to clone monoaminergic receptors from the spiny lobster. Using a novel database mining strategy, we were able to identify several uncharacterized monoaminergic receptors in the Panulirus interruptus genome. We cloned one serotonin (5-HT2βPan) and three dopamine receptors (D1αPan, D1βPan, and D2αPan), and characterized them with regard to G protein coupling and signal transduction cascades. We used a heterologous expression system to show that G protein couplings and signaling properties of monoaminergic receptors are strongly conserved among vertebrate and invertebrate species. This work further shows that DAR-G protein couplings in the stomatogastric nervous system are unique for a given receptor subtype, and receptors can couple to multiple signaling pathways, similar to their mammalian homologs. Custom made antibodies were used to localize monoamine receptors in the stomatogastric ganglion, and in identified neurons. Pyloric neurons show unique receptor expression profiles, which supports the idea of receptor expression as an underlying mechanism for cell-type specific effects of a given modulator. Receptors are localized to the synaptic neuropil, but are not expressed in the membrane of large diameter processes or the soma. The localization of dopamine receptors in identified pyloric neurons suggests that they may respond to synaptic, paracrine or neurohormonal dopamine signals. This work also supports the idea that different types of signals can be generated by a single receptor.

Odor signals mediate a variety of behaviors in animals across a diversity of taxa. Despite dramatic morphological differences between animals from different taxa, several important features of olfactory system organization and processing are similar across animals. Because of this similarity, a number of different organisms including mammals, insects, and decapod crustaceans serve as valuable model systems for understanding general principles of olfactory processing. As in other organisms, including both vertebrates and insects, the chemosensory system of decapod crustaceans is organized into multiple anatomically distinct neuronal pathways. The two main pathways (the aesthetasc/ olfactory lobe pathway and non-aesthetasc/ lateral antennular neuropil pathway) originate in different populations of antennular sensilla and project to different neuropils in the brain. The functional significance of this parallel organization is not well understood in crustaceans or in many other species. Although in some insect species the functions of parallel pathways are clearly delineated by the types of odors processed by each, functional differences between parallel pathways in other organisms are much less distinct. A critical step towards understanding the functional significance of the multiple chemosensory pathways is to identify the specific behaviors that are driven by each pathway. Using spiny lobsters and crayfish as model organisms, the importance of each pathway was examined in three different behavioral contexts: (1) orientation to a distant food odor, (2) shelter selection in response to conspecific chemical signals, and (3) determination of conspecific social status. In each study, selective ablations of specific populations of antennular sensilla were performed, and the behavior of ablated animals was compared to that of intact controls. Results show that either the aesthetasc or non-aesthetasc pathway is capable of driving orientation to food odors, suggesting functional redundancy between the pathways in this behavior. In contrast social odors are processed preferentially by the aesthetasc pathway rather than the non-aesthetasc pathway, suggesting a unique role for the aesthetasc pathway in this context. As in other organisms possessing multiple chemosensory pathways, the dual antennular pathways in crustaceans display both unique and overlapping functions depending on the chemicals examined, and the behavioral context in which the signal is presented.

In insects, ecdysis is an important feature of growth and development and is tightly controlled by a variety of neuropeptides. In holometabolous insects, crustacean cardioactive peptide (CCAP) is one of many factors that regulate ecdysis behaviours; however, not much is known about the control of ecdysis in hemimetabolous insects. In this thesis, the CCAP-signaling pathway is shown to be essential for successful ecdysis in the hemimetabolous insect, Rhodnius prolixus. The cDNA sequence of the CCAP gene has been cloned from the R. prolixus central nervous system (CNS) and the functional role of CCAP as a neuromodulator/neurotransmitter demonstrated. Specifically, the expression of RhoprCCAP in CNS neurons producing extensive CCAP-like immunoreactive processes within the neuropile indicates that CCAP plays central roles in coordination of other neurons. RhoprCCAP also acts as a neurohomone/neuromodulator released peripherally to coordinate many tissues. Thus, CCAP-like immunoreactive processes are found in neurohemal sites and also on peripheral tissues. The RhoprCCAP receptor (RhoprCCAPR) has been cloned and shown to be a G-protein coupled receptor (GPCR). RhoprCCAPR expression is observed in the CNS and certain peripheral tissues of R. prolixus. Also, CCAP stimulates hindgut contractions and increases the heartbeat rate in a dose-dependent manner. The involvement of CCAP in R. prolixus ecdysis has been investigated. Up-regulation of the RhoprCCAP transcript in the CNS and the RhoprCCAP receptor (RhoprCCAPR) transcript in the CNS and specific peripheral tissues was observed immediately prior to ecdysis. Also, decreasing staining intensity of CCAP-like immunoreactivity in neurons immediately following ecdysis indicates the release of CCAP during ecdysis. The critical importance of the CCAP-signalling pathway was further demonstrated by knockdown of the RhoprCCAP and RhoprCCAPR transcripts utilizing double stranded RNA interference. Insects with these transcripts knocked down have high mortality (up to 84%), typically at the expected time of ecdysis, or have ecdysis extremely delayed. Taken together, this thesis demonstrates that RhoprCCAP plays a crucial role in regulating ecdysis behaviours in R. prolixus, and clearly shows the conserved nature of the CCAP-signaling pathway in ecdysis for both holometabolous and hemimetabolous insects.

In insects, ecdysis is an important feature of growth and development and is tightly controlled by a variety of neuropeptides. In holometabolous insects, crustacean cardioactive peptide (CCAP) is one of many factors that regulate ecdysis behaviours; however, not much is known about the control of ecdysis in hemimetabolous insects. In this thesis, the CCAP-signaling pathway is shown to be essential for successful ecdysis in the hemimetabolous insect, Rhodnius prolixus. The cDNA sequence of the CCAP gene has been cloned from the R. prolixus central nervous system (CNS) and the functional role of CCAP as a neuromodulator/neurotransmitter demonstrated. Specifically, the expression of RhoprCCAP in CNS neurons producing extensive CCAP-like immunoreactive processes within the neuropile indicates that CCAP plays central roles in coordination of other neurons. RhoprCCAP also acts as a neurohomone/neuromodulator released peripherally to coordinate many tissues. Thus, CCAP-like immunoreactive processes are found in neurohemal sites and also on peripheral tissues. The RhoprCCAP receptor (RhoprCCAPR) has been cloned and shown to be a G-protein coupled receptor (GPCR). RhoprCCAPR expression is observed in the CNS and certain peripheral tissues of R. prolixus. Also, CCAP stimulates hindgut contractions and increases the heartbeat rate in a dose-dependent manner. The involvement of CCAP in R. prolixus ecdysis has been investigated. Up-regulation of the RhoprCCAP transcript in the CNS and the RhoprCCAP receptor (RhoprCCAPR) transcript in the CNS and specific peripheral tissues was observed immediately prior to ecdysis. Also, decreasing staining intensity of CCAP-like immunoreactivity in neurons immediately following ecdysis indicates the release of CCAP during ecdysis. The critical importance of the CCAP-signalling pathway was further demonstrated by knockdown of the RhoprCCAP and RhoprCCAPR transcripts utilizing double stranded RNA interference. Insects with these transcripts knocked down have high mortality (up to 84%), typically at the expected time of ecdysis, or have ecdysis extremely delayed. Taken together, this thesis demonstrates that RhoprCCAP plays a crucial role in regulating ecdysis behaviours in R. prolixus, and clearly shows the conserved nature of the CCAP-signaling pathway in ecdysis for both holometabolous and hemimetabolous insects.

Climate change will affect all freshwater ecosystems via both direct physiological and indirect, biologically-mediated effects. Small lakes (< 10 ha) numerically dominate the Boreal Shield and represent an important habitat for aquatic biota. Small, shallow lakes are particularly responsive to climate-induced changes in thermal structure. Furthermore, biological interactions may be particularly important in small lakes where space, habitat heterogeneity, and thermal refugia are limited. Therefore, it is critical to understand and predict the consequences of climate change for community dynamics in small Boreal Shield lakes. Using 10 years of monitoring data and a field experiment I tested for differences in crustacean zooplankton community structure between warm and cool lake habitats. I classified years from a small, shallow Boreal Shield lake as ‘warm’ or ‘cool’ based on several characteristics of lake thermal structure. Since macroinvertebrates are often the main predators in small, shallow lakes, I further tested for potential interactions between lake thermal structure and spatially-dependent macroinvertebrate predation using in situ mesocosms. Body sizes of two ubiquitous crustacean zooplankton taxa, Leptodiaptomus minutus and Bosmina spp., were reduced in warm years, but no differences in abundance or diversity were detected at the annual scale. In contrast, in 15d enclosure experiments, crustacean zooplankton abundance and calanoid copepodid body size were reduced by the vertically-migrating predator Chaoborus punctipennis, but only in warm isothermal conditions. Zooplankton lowered their daytime depth distribution to avoid the surface-orienting notonectid predator, Buenoa macrotibialis, regardless of thermal habitat. No predation effect was detected in a hot (25ºC) isothermal habitat where both Chaoborus and notonectids were likely heat-stressed. Differences in abundance effects between the enclosure and monitoring data are likely due to the scales at which the analyses were conducted. Over short timescales predator-prey dynamics depended on lake thermal structure. However, over annual timescales zooplankton response was averaged across periods of seasonal change in thermal structure and biological processes, which may dampen the short-term effects associated with strong predation in isothermal conditions. Therefore, the importance of macroinvertebrate predators in regulating crustacean zooplankton community structure may increase if small lakes become progressively more isothermal with future climate change. / Thesis (Master, Biology) -- Queen's University, 2009-03-31 13:29:35.975

Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-06-28T15:31:52Z No. of bitstreams: 1 TanylaCLS_DISSERT.pdf: 2364338 bytes, checksum: 1e447e8aec29d852bf922c0a8cef2e2f (MD5) / Made available in DSpace on 2017-06-28T15:31:52Z (GMT). No. of bitstreams: 1 TanylaCLS_DISSERT.pdf: 2364338 bytes, checksum: 1e447e8aec29d852bf922c0a8cef2e2f (MD5) Previous issue date: 2017-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of the present study was to evaluate the combined use of ozone technology with modified atmosphere packaging as an alternative to ensure the microbiological safety, quality and shelf life of whole chilled Pacific white shrimp (Litopenaeus vannamei). Shrimp samples were immersed in ozonated water (1 ppm, 10 min) in chlorinated water (5ppm, 10 min), and as control group, shrimp with no treatment was used. After immersion, shrimp samples were drained, and packed in atmospheric air (Control) and modified atmosphere (100% CO2). All samples were stored under refrigeration (4±1°C) for 12 days. Shrimp samples were with drawn every 3 days for microbiological (Salmonella spp, Staphylococcus aureus, total mesophilic and psychrotrophic counts), sensory (Quality index method - MIQ) and physicochemical (pH, total volatile bases nitrogen (TVB-N), Trimethylamine nitrogen (TMA-N) and the measurement of thiobarbituric acid reactive substances (TBARS)) analyzes. The results were statistically evaluated using Univariate Variance Analysis (ANOVA). The Tukey test was used to examine the individual statistical differences between treatments, at a significance level of 0.05.Linear regressions were made to predict the shrimp shelf life. The pre-treatment of the shrimp samples with ozonated water, followed by packaging in modified atmosphere (100% CO2) and storing at refrigeration temperature (4ºC), demonstrated efficacy in increasing the estimated shelf life (24 days), when compared to control group (9 days) and pre-treatment with chlorinated water (11 days). During this period, the sensorial characteristics of pre-treated group with ozone remained acceptable, the melanosis index remained low, the total count of mesophilic and psychrotrophic bacteria remained low, pH, N-BVT, N-TMA and TBARS remained low and constant, when compared to the other treatments. Thus, it can be concluded from these results that the combined effect of ozone and modified atmosphere ensured the physic-chemical and microbiological quality and extended the shelf life of white shrimp (L. vannamei) stored at 4 ° C / O objetivo do presente trabalho foi avaliar o uso combinado da tecnologia de ozônio com a embalagem em atmosfera modificada, como uma alternativa para garantir a segurança microbiológica, a qualidade e o aumento da vida de prateleira do camarão branco do Pacífico (Litopenaeus vannamei) inteiro resfriado. Amostras de camarões foram imersas em água ozonizada (1ppm, 10 min.), em água hiperclorada (5ppm, 10 min.), e como controle utilizou-se camarão sem nenhum tratamento. Após imersão, as amostras foram drenadas, e embaladas em ar atmosférico (Controle) e em atmosfera modificada (100% CO2). Todas as amostras foram armazenadas sobre refrigeração (4±1°C) durante 12 dias. A cada três dias as amostras de camarão foram retiradas para análises microbiológica (Salmonella spp, Staphylococcus aureus, contagem total de mesófilos e psicrotróficos), sensorial (Método do Índice de Qualidade - MIQ) e físico-química (pH, nitrogênio das bases voláteis totais (N-BVT), nitrogênio de trimetilamina (N-TMA) e o teste das substâncias reativas ao ácido 2-tiobarbitúrico (TBARS)). Os resultados foram avaliados estatisticamente através de Análise de Variância Univariada (ANOVA). O teste Tukey foi utilizado para examinar as diferenças estatísticas individuais entre tratamentos, ao nível de significância de 0,05. Regressões lineares foram feitas para predizer a vida de prateleira. O pré-tratamento das amostras de camarão com água ozonizada, seguido da embalagem em atmosfera modificada (100% CO2) e armazenamento na temperatura de refrigeração (4ºC), demonstrou eficácia no aumento da vida de prateleira (24 dias), quando comparado com o controle (9 dias) e pré-tratamento com água clorada (11 dias). Durante esse período, as características sensoriais do grupo pré-tratado com ozônio mantiveram aceitáveis, o índice de melanose manteve-se baixo, a contagem total de bactérias mesófilas e psicrotróficas mantiveram-se baixas, o pH, N-BVT, N-TMA e TBARS mantiveram-se baixos e constantes, quando comparado aos demais tratamentos. Assim, pode-se concluir baseado nesses resultados, que o efeito combinado do ozônio e atmosfera modificada garantiu a qualidade físico-química e microbiológica e estendeu a vida de prateleira do camarão branco (L. vannamei) armazenado na temperatura de 4ºC / 2017-06-28