Thesis (M. Sc.)--Memorial University of Newfoundland, 1997. / Restricted until November 1998. Bibliography: leaves 123-137.

The mechanisms of dung inhabiting insects' heterotrophic succession were studied by preventing the colonisation of early successional insect. The early successional insect, predominantly the large larvae of Calyptratae Diptera, both facilitated and inhibited the later establishing insect. Whereas the removal of early successional species affected negatively the late successional Coleoptera (facilitation), the small late successional larvae of Acalyptratae Diptera were affected positively (inhibition). The patterns retrieved from the heterotrophic succession strongly resemble the patterns retrieved from the autotrophic, mostly plant, succession Therefore it is possible to suggest, that similar mechanisms are behind both the autotrophic and the heterotrophic succession.

Heterotrophic plate counts (HPCs) are commonly used to assess the general microbiological quality of drinking water. Drinking water quality specifications world-wide recommend HPC limits from 100 to 500 cfu.m1-1. However, a number of recent studies revealed evidence that commonly used indicator bacteria may not be as harmless as generally accepted. It appears that immuno-compromised individuals, which represent increasing components of many consumer populations, are particularly at risk. This would include the very young and very old, patients with diseases such as AIDS, and patients on therapy after organ transplantations and cancer treatment. Since, epidemiological and animal infectivity studies are complex and difficult to control, attempts have been made by researchers to examine HPCs directly in order to assess health risks. These analyses included: cytotoxicity, invasiveness, enzyme analyses, antibiotic susceptibility and identification. In this study, 339 bacterial colonies were isolated at random from selected drinking water supplies in South Africa using heterotrophic plate count tests. In a first step to screen for potentially pathogenic properties, 188 (55.5%) of the isolates showed α- and β-haemolysis on human- and horse-blood agar media. Subsequent analysis of the haemolytic isolates for enzymatic properties associated with pathogenicity revealed the presence of chondroitinase in 5.3% of the isolates, coagulase in 16.0%, DNase in 60.6%, elastase in 33 .0%, fibrinolysin in 53.7%, gelatinase in 62.2%, hyaluronidase in 21. 3 %, lecithinase in 47.9%, lipase in 54.8%, and proteinase in 64.4%. Fluorescein and pyocyanin were not produced by any of the isolates. The Kirby-Bauer quality controlled disc diffusion method was applied in the demonstration of antibiotic resistance by the HPC isolates. Among the haemolytic isolates 77.7% were resistant to oxacillin (1 µg), 59.6% to penicillin G (2 units), 47.3% to penicillin G (10 units), 54.3% to ampicillin (10 µg) and 43.1% to ampicillin (25 µg). Cell culture studies revealed that 96% of haemolytic isolates were cytotoxic to HEp-2 cells and 98.9% of the 181 cytotoxic isolates adhered to HEp-2 or Caco-2 cells. Gram-negative isolates tended to adhere in larger numbers than gram-positive isolates. The average index of adherence for Gram-negative bacteria was 20-30 bacteria per HEp-2 cell, compared to 3-7 for Gram-positive bacteria. HEp-2 cells were invaded by 43.6% and Caco-2 cells by 49.7% of the 181 cytotoxic isolates. The invasion index on HEp-2 cells was 1.9xlO-1 to 8.9xl0-6, compared to 7.7xl0-2 to 8.3xlO-6 on Caco-2 cells. The most commonly isolated genera showing potentially pathogenic features were: Aeromonas, Acinetobacter, Aureobacterium, Bacillus, Chryseobacterium, Corynebacterium, Klebsiella, Moraxella, Pseudomonas, Staphylococcus, Tsukamurella and Vibrio. All these genera are known to contain opportunistic pathogens. Our results support earlier findings on potentially pathogenic features of bacteria detected by heterotrophic plate counts on drinking water. These findings seem to be in agreement with some epidemiological studies, which indicated an association between HPCs of drinking water and the incidence of gastroenteritis in consumers. However, the extent of the health risk concerned needs to be defined in detail for meaningful revision of quality guidelines for HPCs in drinking water. / Dissertation (MSc (Medical Virology))--University of Pretoria, 2005. / Medical Virology / unrestricted

Picoplankton, cells between 0.2 - 2 μm, play a vital role in the carbon flow and nutrient cycling in marine food webs. Auto- and heterotrophic picoplankton dominate the biomass of oligotrophic tropical and subtropical oceans. However, little is known about their vertical distribution, changes in space and time and their relationships with environmental variables in the central Red Sea. The goal of this Ph.D. dissertation is to obtain baseline knowledge about their abundance, cellular characteristics (cell size, relative pigment and nucleic acid content) and biomass at seasonal and high-frequency temporal resolution (every 2 hours). This dissertation also aims at assessing picoplankton responses to separate and joint effects of nutrients additions (inorganic, organic and mixed) and temperature in order to be able to predict the relative contribution of eutrophication and warming in the future standing stocks of picoplankton in the Red Sea. I conducted a total of 63 vertical profiles (15 at around noon plus 48 more from the high-frequency diel samplings) from the surface down to the bottom (ca. 700 m) at a station situated 6 km off the coast of King Abdullah Economic City (KAEC) in the central Red Sea and performed 4 nutrient and temperature experiments lasting each 6 days with surface waters from the harbor of King Abdullah University of Science and Technology (KAUST). Flow cytometry allowed me to consistently identify five groups of autotrophs (Prochlorococcus, two populations of Synechococcus separated by their relative phycoerythrin fluorescence, and two differently-sized groups of picoeukaryotes) and two groups of heterotrophic prokaryotes characterized by their different relative nucleic acid content. One of the most surprising findings is the relatively lower abundances and to a lesser extent also growth rates of picoplankton compared with other tropical and subtropical oceans. Seasonality in environmental conditions emerged as an important factor in the response of picoplankton to nutrient additions and temperature. Picoplankton mostly responded to inorganic and mixed nutrient additions rather than warming. Overall, the information provided in this dissertation fills the gap of a critical component of Red Sea pelagic ecosystems and expands the information available on picoplankton communities in tropical waters.

No description available.

No description available.

Dominant genera of bacteria were isolated from three river waters during anthracene and pentachlorophenol biotransformation studies. The genera Pseudomonas, Acinetobacter, Micrococcus, Chromobacterium, Alcaligenes, Azomonos, Bacillus, and Flavobacterium were capable of biotransforming one or both of these compounds. These isolates were subjected to further biotransformation tests, including river water and a basal salt medium with and without additional glucose. The results of these experiments were evaluated statistically. It was concluded that only a limited number of the bacteria identified were able to transform these chemicals in river water. The addition of glucose to the growth medium significantly affected the biotransformation of these chemicals. It was also determined that the size of the initial bacterial population is not a factor in determining whether biotransformation of anthracene or pentachlorophenol can occur.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-14T15:59:47Z No. of bitstreams: 1 Joao Paulo Viana de Lima.pdf: 751024 bytes, checksum: 12aea5280a52c50190be7cbe5d4985dc (MD5) / Made available in DSpace on 2017-02-14T15:59:47Z (GMT). No. of bitstreams: 1 Joao Paulo Viana de Lima.pdf: 751024 bytes, checksum: 12aea5280a52c50190be7cbe5d4985dc (MD5) Previous issue date: 2007-04-27 / The accumulation of toxic nitrogenous compounds in the water is a common problem to aquaculture systems. Recent works have showed good results in terms of production and nitrogen retention efficiency, through the addition of organic carbon source (sugar, molasses, etc). This work investigated the effect of molasses addition in different C:N ratios on the water quality, microbial activity and production, in semi-intensive experimental culture tanks of Litopenaeus vannamei with no water exchange. Four treatments and three replicates were adopted, which three with daily molasses addition in 5, 10 and 15:1 C:N ratio and one control with no carbon source addition. Twelve 500 L fiber glass tanks were stocked with 25 shrimps.m-2 (1.90±0.37 g). Shrimps were fed with a 35% crude protein commercial diet offered in feeding trays at 08:00 and 16:00. Phytoplankton, bacteria and water samples were collected fortnightly during the culture. The 15:1 and 10:1 C:N ratios showed lower (P<0.05) oxygen dissolved levels (4.64 and 4.76 mg L-1, respectively) which is related with the major organic carbon supply in these ratios. Molasses addition resulted in lower (P<0.05) nitrogenous compounds levels (nitrite and nitrate), as well reducing in the cianobacteria densities in the C:N 10 and 15:1 treatments. No significant differences (P≥0.05) were found in Vibrio spp, autotrophic and heterotrophic bacterial densities. Shrimp final weight (~12.3 g)and weigth gain (~1.04 g.week-1) in high C:N ratios (10:1 and 15:1) were higher (P<0.05) than in the others treatments. Specific growth rate was high in all treatments (2.53 to 2.69 % day-1), but the 10:1 ratio was higher than the control. Yield values ranged from 267.4 to 301.0 g m-2 with no significant difference (P≥0.05) among treatments. This study shows that the molasses can be used as carbon source in order to increase C:N ratio, improving the water quality and the L. vannamei semi-intensive culture performance with no water exchange. / O acúmulo de formas tóxicas de compostos nitrogenados na água é um grande problema para os sistemas aqüícolas. Pesquisas recentes têm demonstrado resultados satisfatórios em termos de produção e eficiência de retenção do nitrogênio, através da adição de fontes de carbono orgânico (açúcar, melaço, etc.). O presente estudo investigou o efeito da adição de melaço em diferentes relações C:N sobre a qualidade da água, atividade microbiana e a produção semi-intensiva do camarão Litopenaeus vannamei, em tanques de cultivo experimental sem renovação de água. Foram adotados quatro tratamentos e três réplicas, sendo três com aplicação diária de melaço nas relações C:N 5, 10 e 15:1, e um controle, sem aplicação desta fonte de carbono. Foram utilizados 12 tanques em fibra de vidro (500 L), estocados com 25 camarões.m-2 (1,90±0,37 g). A alimentação constou de ração comercial com 35% de proteína bruta e foi ofertada diariamente em bandejas às 8 e 16h. Coletas de água para análise química e de material biológico (fitoplâncton e bactérias) foram realizadas quinzenalmente ao longo do cultivo. As relações 15:1 e 10:1 apresentaram os menores (P<0,05) níveis de oxigênio dissolvido (4,64 e 4,76 mg L-1, respectivamente) que está relacionado ao maior aporte de carbono orgânico nestas relações. O melaço reduziu significativamente (P<0,05) as concentrações dos compostos nitrogenados, nitrito e nitrato, bem como reduziu as densidadesde cianobactérias nos ambientes com relações C:N de 10 e 15:1. Nenhum efeito (P≥0,05) foi observado em relação às bactérias autotróficas, heterotróficas e Vibrio spp. O peso final dos camarões (~12,3 g) e o ganho de peso individual (~1,04 g.semana-1), nas relações C:N mais altas (10:1 e 15:1), foram superiores (P<0,05) aos demais tratamentos. A taxa de crescimento específico foi elevada em todos os tratamentos (2,53 a 2,69 % dia-1), entretanto os indivíduos na relação 10:1 foi superior (P<0,05) ao controle. Os valores de produção variaram de 267,4 a 301,0 g m-2, e não foram diferentes estatisticamente (P≥0,05) entre os tratamentos. O melaço pode ser utilizado como fonte de carbono para incrementar a relação C:N, melhorando a qualidade da água e os níveis de produtividade em cultivo semi-intensivo de L. vannamei sem renovação de água.

Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-08T14:02:41Z No. of bitstreams: 2 LARISSA DA CUNHA.pdf: 1240653 bytes, checksum: 370a84da7c6dcb42867146f0c15487b1 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-08T14:03:55Z (GMT) No. of bitstreams: 2 LARISSA DA CUNHA.pdf: 1240653 bytes, checksum: 370a84da7c6dcb42867146f0c15487b1 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2016-09-08T14:03:55Z (GMT). No. of bitstreams: 2 LARISSA DA CUNHA.pdf: 1240653 bytes, checksum: 370a84da7c6dcb42867146f0c15487b1 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2016-07-21 / Com o objetivo de avaliar a possibilidade da produção de guppy (Poecilia reticulata) em sistema com bioflocos, dois experimentos foram desenvolvidos no Laboratório de Aquariofilia da Universidade Federal do Pampa, Uruguaiana, RS. Os experimentos foram realizados em delineamento inteiramente casualizado e os resultados foram submetidos à análise de variância ANOVA e à comparação das médias pelo teste de Tukey (5%). O primeiro estudo objetivou avaliar o desempenho produtivo de juvenis de guppys (comprimento total inicial de 18,06 ± 0,30 mm e peso inicial de 0,056 ± 0,003 g), produzidos em sistema de bioflocos com diferentes taxas de alimentação, comparando-os com um sistema de produção em água clara. Foram avaliados quatro tratamentos, com quatro repetições: sistema de água clara (controle) com oferta de ração a 3% do peso vivo (SAC), sistema enriquecido com bioflocos sem a oferta de ração (BFT0), sistema enriquecido com bioflocos com oferta de ração a 1,5% do peso vivo (BFT1.5) e sistema enriquecido com bioflocos com oferta de ração a 3% do peso vivo (BFT3). Os parâmetros de qualidade da água foram monitorados semanalmente. Os resultados demonstraram que os tratamentos enriquecidos com bioflocos apresentaram melhor controle dos níveis de amônia da água. Ao final do período experimental os animais dos tratamentos SAC, BFT0 e BFT1.5 não apresentaram diferenças significativas entre si, para as variáveis CT, CP, peso e TCE. No entanto, todos os tratamentos foram inferiores ao tratamento BFT3 em todas as variáveis de desempenho analisadas. Em contrapartida, a CAA não apresentou diferença significativa entre os tratamentos BFT1.5 e BFT3, sendo o tratamento SAC mais elevado que os demais. A sobrevivência foi superior nos tratamentos com oferta de ração. O segundo estudo objetivou avaliar o desempenho produtivo de juvenis de guppys (comprimento total inicial 12,10 ± 0,13 mm e peso inicial 0,015 ± 0,000 g) submetidos à ciclos de restrição alimentar e realimentação em sistema de bioflocos. Foram avaliados três tratamentos, com seis repetições: sistema de água clara (controle) com alimentação diária (SAC), sistema enriquecido com bioflocos com alimentação durante cinco dias seguidos de dois dias de restrição de alimento (BFTR) e sistema enriquecido com bioflocos com alimentação diária (BFT). Os animais foram produzidos até entrarem no período reprodutivo e os parâmetros de qualidade da água foram mensurados semanalmente. Os resultados demonstram que os sistemas de cultivo BFT com e sem restrição alimentar apresentaram melhor controle dos níveis de nitrito em comparação ao sistema em água clara. Os animais produzidos nos sistemas BFT com e sem restrição alimentar atingiram o período reprodutivo na metade do tempo necessário para os animais produzidos em sistema de água clara, assim como apresentaram melhor desempenho produtivo (CT, CP, Peso, CAA e TCE). Os resultados sugerem que o sistema BFT pode ser empregado no cultivo de guppys, servindo como fonte alimentar aos organismos cultivados, melhorando o desempenho produtivo e os parâmetros de qualidade da água. / In order to assess the feasibility of guppy (Poecilia reticulata) production in system with bioflocs, two experiments were developed in Aquariofilia Laboratory of Federal University of Pampa, Uruguaiana, RS. The experiments were conducted in a completely randomized design and the results were submitted to analysis of variance ANOVA and the comparison of means by Tukey test (5%). The first study aimed to evaluate the performance of juvenile guppys (initial total length of 18.06 ± 0.30 mm and initial weight 0.056 ± 0.003 g), produced in biofloc system with different feed rates, comparing to a production system in clear water. Four treatments were evaluated with four replicates: clear water (control) system with feed supply 3% of body weight (CWS), biofloc technology system without the supply of feed (BFT0), biofloc technology system with feed supply 1.5% of body weight (BFT1.5) and biofloc technology system with feed supply 3% of body weight (BFT3). Water quality parameters were monitored weekly. The results showed that biofloc treatments showed better control of water ammonia levels. At the end of experiment the animals CWS, BFT and BFT1.5 showed no significant differences, for TL, SL, weight and SGR. However, all treatments were lower than BFT3 treatment in all three performance variables. In contrast, the FCR had no significant difference between the BFT1.5 and BFT3 treatments, being CWS the highest treatment. Survival was superior in the treatments with supply of feed. The second study aimed to evaluate the performance of juvenile guppys (initial total length 12.10 ± 0.13 mm and initial weight 0.015 ± 0.000 g) submitted to food restriction and refeeding cycles in biofloc system. Three treatments were evaluated, with six replications: clear water (control) system with daily food (CWS), biofloc technology system with food for five days followed by two days of food restriction (BFTR) and biofloc technology system with daily food (BFT). The animals were maintained until they enter the reproductive period and water quality parameters were measured weekly. The results demonstrate that the BFT cultivation systems with and without feed restriction showed better control of nitrite levels compared to the system in clear water. Animals produced in BFT systems with and without food restriction reached the reproductive period at half time required for animals produced in clear water system, and showed better growth performance (TL, SL, Weight, FCR and SGW). These results suggest that BFT system can be employed in guppys farming, serving as food source for organisms grown, improving growth performance and water quality parameters.

O monitoramento da qualidade da água de diálise caracteriza uma importante ferramenta para a tomada de decisões quando resultados laboratoriais insatisfatórios são disponibilizados em curto período de tempo. Os inconvenientes relacionados ao tempo de espera para a obtenção dos resultados têm conduzido à busca de métodos microbiológicos alternativos que permitam obter dados exatos, precisos e em menor tempo do que os obtidos por métodos clássicos. Este projeto teve por finalidade avaliar o desempenho do método microbiológico alternativo para a contagem de bactérias heterotróficas em água tratada para diálise através da técnica de detecção microbiana pelo uso de fluorescência. Inicialmente foi realizada a determinação do tempo mínimo de incubação para obtenção de valores de contagem confiáveis pelo método alternativo, seguido pela avaliação de desempenho do método contemplando todos os parâmetros estabelecidos em compêndios nacionais e internacionais e a demonstração da equivalência do método alternativo frente ao método tradicional, através da avaliação de 23 amostras de água tratada para diálise. Os resultados demonstraram que o método alternativo permite a quantificação de bactérias heterotróficas após 40 horas de incubação, com exatidão e precisão para o range de 5 a 100 UFC/placa, resultando em uma redução de aproximadamente 67% do tempo atualmente empregado no método tradicional. Portanto, a técnica de detecção microbiana pelo uso de fluorescência se mostrou uma opção viável para a implementação de um método microbiológico rápido para a contagem de bactérias heterotróficas em amostras de água tratada para hemodiálise. / Monitoring the quality of dialysis water is an important tool for decision-making when unsatisfactory results are available in a short period of time. The drawbacks related to waiting time for obtaining results have led to the search for alternative microbiological methods that allow accurate data to be obtained in less time than those obtained by classical methods. This project aimed to evaluate the alternative microbiological method performance for the heterotrophic bacteria counts in dialysis treated water through the microbial detection technique using fluorescence. Initially, the determination of the minimum incubation time to obtain reliable count values by the alternative method was performed, followed by the performance evaluation of the method, considering all the parameters established in national and international compendiums and demonstrating the equivalence of the alternative method to the traditional method, through the evaluation of 23 samples of dialysis treated water. The results demonstrated that the alternative method allows quantification of heterotrophic bacteria after 40 hours of incubation, with accuracy and precision for the range of 5 to 100 CFU/plate, resulting in a reduction of approximately 67% of the time currently used in the traditional method. Therefore, the microbial detection technique using fluorescence showed a viable option for the implementation of a rapid microbiological method for the heterotrophic bacteria counts in samples of treated water for hemodialysis.