D.Phil. / The main objective of this study was to describe the population genetic structure of African Whitebacked Vultures (Pseudogyps africanus) and to compare values to those previously documented for the Cape Griffon Vulture (Gyps coprotheres). The percentage of polymorphic .loci (P = 34.15%, 0.99 criterion) and average heterozygosity (17 = 0.108, ±0.032) calculated for P. africanus, confirm low levels of genetic -variation as reported for G. coprotheres. Blood samples' obtained from Lappetfaced (Torgos, tracheliotos) and Egyptian (Neophron percnopterus) Vultures enabled an evaluation of the genetic differentiation among the four southern African vulture species from allele frequency data assessed at 19 presumptive gene loci. Six (31.58%) of the 19 shared loci were polymorphic. Values of 1.26 (10.1), 26.32% and 0.076 (±0.047) for P.'africanus, 1.21 (±0.1), 21.05% and 0.097 (±0.045) for T. tracheliotos, 1.11 (±0.7), 21.05%. and 0.053 .(±0.053) for N: percnopterus and 1.05 (±0.5), 5.26% and 0.044 (±0.047) for G. coprotheres were obtained for the mean number of alleles per locus, P and Ti respectively. An average between-population fixigion index (FsT) value of 0.322 was obtained, which is indicative of significant (P < 0.01) differentiation between the four accipitrid species studied. Reference values for some haematological and plasma chemical parameters were established in 33 apparently normal, free-living, African Whitebacked Vulture nestlings. This .information can be. used in future ornithological research. A total of 27 variables . were examined, which include: leucocyte and erythrocyte counts, haemoglobin concentration, .haematocrit, haematimetric indices, glucose, creatinine, urea, total prOtein, albumin, globulin, albumin/globulin ratio, cholesterol, total lipids, triglycerides, aspartate aminotransferase, cholinesterase, lactate dehydrogenase, alkaline phosphatase, calcium, phosphorus, chloride, potassium, sodium and osmolarity. Only five parameters exhibited statistically significant (p < 0.05) differences between the two populations assayed. The Sandveld population showed elevated mean corpuscular haemoglobin concentration and alkaline phosphatase levels relative to the Dronfield population, whereas, the latter group displayed higher erythrocyte counts and potassium and sodium values than birds from the Sandveld community. Gaschromatography was used to establish the presence of quantifiable . residues .of 14 persistent chlorinated hydrocarbon pollutants in whole blood, clotted blood, heart, kidney, liver, bone, fat and muscle samples obtained from individual African Whitebacked, Cape. Griffon and Lappetfaced Vultures from different localities in South Africa. Concentrations of seven essential elements (Ca, Co, Cr, Cu, Fe, Mn and Zn) and four toxic metals (Al, Ni, Pb and Sr) were, furthermore, measured. The levels of pollutants measured in whole blood samples of live specimens were compared between nestlings from two natural breeding colonies, adults from a wildlife area and birds held in captivity. Statistically significant differences between populations were detected in geometric means calculated for y-BHC, a-chlordane and a-endosulfan. Five of the organochlorine contaminants displayed significant variations between concentrations detected in the clotted blood, organs and muscles excised from vulture carcasses. This includes residues ofy-BHC, a-chlordane, dieldrin, ,8-endosulfan and heptachlor epoxide. Values of the respective organochlorines obtained in vulture samples were generally low in comparison to results documented for a number of avian species. Levels of the , majority of metals analysed differed significantly- between two or more of the sampling localities, between adults and nestlings, and between captive and wild individuals. Metals which did not occur in such distinctly defining concentrations were Sr, Cu and Fe. Birds from Moholoholo maintained the highest overall blood metal burden, while nestlings from Dronfield were the least contaminated Significant differences were present between two or more tissues types for all the metals. The predominant sites for metal accumulation in vultures were the fatty tissues and bones. Most of the levels of metals measured in vultures compared well with concentrations reported for other avian species, and were generally within the range documented for species devoid of deleterious symptoms induced from heavy metal poisoning. However; certain individuals exhibited potentially toxic concentrations of specific metals such as Cu, Fe, Ni, and Pb. Continual monitoring of breeding colonies is recommended. The suitability of African Whitebacked Vulture nestlings as basic bioindicatori is highly advocated. The genetic data from this study can be used to compare levels of genetic diversity remaining in captive and wild vulture populations. An assessment of the amount and pattern of genetic variation of current populations of vulture species is an essential step towards ensuring the longterm survival of these birds. The phylogenetic conclusions found in. this study through allozyme electrophoresis correspond to results obtained from nucleotide sequence studies of the mitochondrial cytochrome b. gene. This points to an extent of positive corroboration between the two techniques. The haematological profile established for African Whitebacked Vulture nestlings constitutes a set of reference values that was previously unavailable for southern African vulture species. This data can assist in diagnosing and monitoring pathological and clinical' incidents detected in vultures. Values for a number of organochlo?ine pesticides and heavy metals, which have not been analysed in vulture species in the past, are documented. These values can serve as guidelines for future research, as well as control values for monitoring the occurrence and distribution of these contaminants within the habitats of vulture species. This study, therefore, presents information for research fields directly related to the survival of vulture populations. These factors must be included in future vulture management and reintroduction programmes as they will serve to enhance the success of conservation attempts.

No description available.

No description available.

No description available.

Torrecillas Lagoon in the North Coast of Puerto Rico has experienced extensive anthropogenic influence over the past 400 years. Elevated concentrations of Potential Toxic Elements (PTEs) have been reported in surficial sediments. The main goal of this dissertation was to implement in Puerto Rico the use of benthic foraminifers as a bioindicators of PTEs and to compare the impact of Cu(II) on field samples with results of experimental work using cultures. Analyses included geochemical assessment for bulk and carbonate- soluble bioavailable concentrations of PTEs in surface, core and pore-water samples, as well as analyses of grain-size, Percent Total Organic Carbon (%TOC), Percent Carbonate (%CO3), foraminiferal assemblages and distribution, and ecological indices. PTEs of concern (Cu, Zn, Ni, Pb, Cr, As, Li, Se, Fe, Mn, V, Se) have relatively uniform spatial distributions. Areas with higher concentrations are associated with higher %TOC and %mud, as well as with anoxic conditions. Temporal distributions show limited variability although an overall decrease in enrichment indicates improvement of environmental conditions in the 20th century. Ammonia beccarii, Quinquloculina rhodiensis, Q. seminulum, and Ammobaculites agglutinans are the dominant foraminifers in the lagoon and are characteristic of stressed coastal environments. Several PTEs, including bioavailable Cu and Zn are negatively correlated with the dominant foraminiferal taxa and with diversity indices, indicating that these pollutants are influencing the spatial and temporal distributions of foraminiferal assemblages. Ammonia beccarii abundance negatively correlates with bulk concentration of Cu(II) and exhibits no correlation with its bioavailable fraction. These observations suggest that fractionation and bioavailability of PTEs need to be considered more in depth as influences on ecological indices and foraminiferal behavior. Exchangeable and oxidizable fractions are considered the most likely to influence the ecology of foraminifers under most circumstances. Ammonia aomoriensi was exposed to Cu(II) concentrations (0–0.32 µmol/L) under controlled conditions (25ºC, 35PSU and pH= 7.8). After a 23-day treatment, foraminifers exposed to 0.22 and 0.32 µmol/L concentrations exhibited reduced growth and morphological deformities in which the long axis of the chamber extended ventrally, increasing the height of the trochospire. The waters in Torrecillas lagoon show strong stratification, with hypoxic/anoxic (DO/L) and corrosive (pH< 7.4) conditions below 4 m depth. The presence of such strong gradients in very shallow water represents a dynamic chemical environment, with changes occurring on day-night cycles, tidal cycles, and especially with storm activity that induces mixing of otherwise highly stratified, very localized waters. Recognizing the potential for sequestered PTEs to be mobilized is essential insight for coastal management agencies that must assess the risks of existing PTEs during coastal engineering activities (e.g., dredge and fill activities) and major storm events.

[pt] Três perfis sedimentares foram coletados na Baía de Guanabara a fim de realizar um estudo geocronológico de contaminação por cromo, cobre e chumbo. As velocidades de sedimentação e a cronologia foram obtidas através das atividades de (210)Pb nos perfis dos sedimentos. Na região oeste foram observadas três taxas de sedimentação: 0,14 (+-) 0,02 cm ano(-1) antes de 1926; 0,65 (+-) 0,03 cm ano (-1) entre 1926 e 1960; 1,00 (+-) 0,02 cm ano(-1) desde então. No leste da baía a velocidade encontrada foi de 1,43 (+-) 0,18 cm ano (-1) desde 1948. No noroeste foram encontradas três velocidades de sedimentação: 0,23 (+-) 0,01 cm ano (-1) antes de 1950; 0,64 (+-) 0,02 cm ano (-1) entre 1950 e 1987; 1,10 (+-) 0,17 cm ano (-1) desde 1987. As concentrações de metais foram determinadas pela técnica de ICP-MS após digestão dos sedimentos em água régia. No oeste da baía as concentrações variaram entre 117 e 172 (u)g g(-1) para Cr; 46,2 e 118 (u)g g (-1) para Cu e 56,0 e 110 (u)g g(-1) para Pb. No leste estas concentrações variaram entre: 101 e 181 (u)g g(-1) para Cr; 54,3 e 78,9 (u)g g(-1) para Cu; 45,5 e 88,6 (u)g g(-1) para Pb. No noroeste as concentrações variaram entre: 96,6 e 790 (u)g g(-1) para Cr; 18,6 e 109 (u)g g(-1) para Cu; 44,9 e 109 (u)g g(-1) para Pb. O índice de geoacumulação demonstrou que os sedimentos da região noroeste apresentam os maiores problemas de contaminação, estando moderado a fortemente contaminado por Cr, moderadamente contaminado por Cu e pouco a moderadamente contaminado por Pb. / [en] Three sediment profiles were collected in the Guanabara Bay aiming at the development of a geochronogical study of contamination by chromium, copper and lead. The sedimentation rate and the chronology were obtained through the activities of (210)Pb in the sediment profiles. In the western region, three sediment rates were observed: 0.14 (+-) 0.02 cm year(-1) before 1926; 0.65 (+-) 0.03 cm.year(-1) between 1926 and 1960; 1.00 (+-) 0.02 cm.year(-1) since then. In the eastern area of the bay, a sedimentation rate of 1.43 (+-) 0.18 cm.year (-1) was detected since 1948. In the northwestern area, three sedimentation rates were verified: 0.23 (+-) 0.01 cm.year (-1) pre-1950; 0.64 (+-) 0.02 between 1950 and 1987; 1.10 (+-) 0.17 cm.year (-1), since 1987. The concentration of metals were determined by means of the ICPMS technique after digestion with aqua regia. The metal concentration in the western area of the bay varied between 117 and 172 (u)g g(-1) for Cr; 46.2 and 118 (u)g g(-1) for Cu; 56.1 and 110 (u)g g(-1) for Pb. In the eastern area, this concentration varied between: 101 and 181 (u)g g(-1) for Cr; 54.3 and 78.9 for Cu; 45.5 and 88.6 for Pb. In northwestern the variations were: 96.6 and 790 (u)g g(-1) for Cr; 18.6 and 109 (u)g g(-1) for Cu; 44.9 and 109 (u)g g(-1) for Pb. The geoaccumulation index signalizes that the sediments of northwestern area presents major problems of contamination, being moderately/strong contaminated by Cr, moderately contaminated by Cu and uncontaminated/moderately contaminated by Pb.

[pt] A busca por tecnologias alternativas e de baixo custo operacional para a remoção de metais em efluentes tem direcionado a atenção para a biossorção. Recentemente vários materiais de origem biológica, como bactérias e resíduos agro-industriais têm sido utilizados para a remoção de íons metálicos de efluentes industriais. A biossorção de metais pesados por espécies biológicas envolve vários mecanismos que, em geral, dependem das espécies biológicas utilizadas e do processamento da biomassa. O cobalto e o manganês são amplamente utilizados em muitas aplicações industriais, e consequentemente, estão presentes nos efluentes provenientes de vários processos industriais, como por exemplo na mineração e produção de ligas. O objetivo deste trabalho foi investigar a eficiência do Rhodococcus opacus, que apresenta vários grupamentos fenólicos e carboxílicos (capazes de interagir com íons metálicos em solução), como adsorvente para a remoção de Co(II) e Mn(II) de soluções aquosas, visando futuras aplicações para o tratamento de efluentes. A caracterização física da superfície do R. opacus foi realizada com MEV, potencial zeta e análises de FTIR. A biomassa, R. opacus, foi previamente tratada com 0,1 mol.L(-1) NaOH e usada em todos os experimentos de biossorção. Todos os testes de biossorção foram realizados em batelada e os parâmetros avaliados foram: pH, concentração da biomassa e do metal, tempo de contato e temperatura. Os melhores valores de pH para a biossorção de Co(II) e Mn(II) foram 7,0 e 5,0, respectivamente. Para ambos os metais estudados, a capacidade de biossorção específica foi maior em soluções contendo baixas concentrações de metais. Para os dois metais, o processo de biossorção foi melhor descrito pelo modelo de Langmuir e pelo modelo cinético de pseudo segunda ordem. Os parâmetros termodinâmicos como DeltaG, DeltaS e DeltaH foram calculados e os processos de biossorção para a remoção do Co(II) e do Mn(II) a partir de soluções aquosas foram consideradas reações endotérmicas e exotérmicas, respectivamente. Este trabalho mostra que o R. opacus pode ser aplicado para a remoção de íons de Co(II) e Mn(II) de soluções aquosas. Após 180 minutos de contato da biomassa com as soluções contendo Co(II) e Mn(II), 84 por cento e 97 por cento dos íons metálicos presentes em solução foram removidos. / [en] The search for alternative technologies and low operating cost for removal of heavy metals from effluent has directing attention to biosorption. Recently, various biological materials, such as bacteria and agro‐waste, have been used for removal of metallic ions from industrial effluents. Biosorption of heavy metals by biological species involves several mechanisms that, in general, depending on the type of specie used and biomass processing procedure. Cobalt and manganese are widely used in many industrial applications, consequently they are present in effluent derived from various industrial processes, for example: mining, alloy production. The objective of this work is to investigate the efficiency of Rhodococcus opacus, which presents various phenolic and carboxylic groups (able to interact with metal ions in solution), as an adsorbent for the removal of Co(II) and Mn(II) from aqueous solutions, aiming future applications for the treatment of effluents. Surface physical characterization of R. opacus was carried by MEV, zeta potential and FTIR analysis. The biomass, R. opacus, was previously treated with 0.1 mol.L(-1) NaOH solution and used in all biosorption experiments. All the biosorption tests were carried out in batch and the parameters evaluated were: pH, concentration of biomass and metal, contact time and temperature. The best pH value for biosorption of Co(II) and Mn(II) were 7.0 and 5.0 respectively. For both metal studied, the specific biosorption capacity was higher in solutions containing low metals concentrations. For both metals, the biosorption process was better described by the Langmuir and pseudo-second-order kinetic models. The thermodynamics parameters, such as DeltaG, DeltaS and DeltaH were calculated and the biosorption process for Co(II) and Mn(II) removal from the aqueous solutions were considered endothermic and exothermic reactions, respectively. This work shown the R. opacus can be applied for removal Co(II) and Mn(II) ions from aqueous solutions. After 180 min contact of biomass with solutions containing Co(II) and Mn(II), 84 per cent and 97 per cent of the metallic ion present in the solutions were removed.

Magister Scientiae (Biodiversity and Conservation Biology) / The aim of the study was to quantify the extent of inorganic chemical pollution of the Franschhoek River and draw relationships between contaminants in water, sediment and plants. The invasive Acacia mearnsii and Salix babylonica and indigenous Brabejum stellatifolium species were chosen as biomonitors due to their wide spread distribution along the river and their apparent ability to accumulate heavy metals. The sites chosen allowed for comparison of the river quality upstream with that of the river further down stream as it meandered through residential, agricultural and recreational areas, until it joined with the Berg River further downstream. The general aim of the study was to assess the degree of inorganic pollution in the Franschhoek River to evaluate its contribution to pollution of the Berg River, of which it is an important tributary. Also understanding the sources of the pollution would contribute to the ability to reduce pollution. / South Africa

Please read the abstract in the section 00front of this document / Thesis (PhD (Medical Immunology))--University of Pretoria, 2008. / Immunology / unrestricted

Durant cette dernière décennie, plusieurs voies de régulation de l’homéostasie de différents ions ont été identifiées chez les plantes. Le croisement des données de la littérature révèle l’existence de connexions insoupçonnées entre ces différentes voies de régulation, limitant ainsi les perspectives d’apporter des solutions adaptées pour chaque élément. En effet, la carence ou l’excès en un seul élément cause une profonde perturbation de l’homéostasie des autres éléments associés. Un exemple frappant illustrant l’interconnexion entre l’homéostasie des ions est celui qui concerne le phosphate inorganique (Pi), le zinc (Zn) et le fer (Fe). Dans ce contexte, l’objectif de mon travail de thèse est de mieux comprendre les bases physiologiques et moléculaires de l’interaction entre le Pi, le Zn et le Fe chez les plantes. Trois plantes ont été utilisées dans ce travail : la plante modèle Arabidopsis thaliana, et deux plantes d’intérêt agronomique, la laitue (Lactuca sativa) et le riz (Oryza sativa L.). Chez la laitue, mes résultats montrent l’existence d’une base génétique pour la co-régulation de l’homéostasie du Pi et de celle du Zn chez les deux variétés de laitue utilisées, toute en y révélant un comportement contrasté. Chez le riz, j’ai prouvé également l’existence d'une base génétique pour les interactions non seulement entre les homéostasies du Pi, et celle du Zn et mais aussi avec celle du Fe, et j'ai démontré un rôle important du transporteur du Pi OsPHO1;1 dans ce processus. Enfin, en utilisant l’approche de génétique d’association, de nouveaux gènes impliqués dans les interactions homéostatiques Pi-Zn ont été caractérisés chez Arabidopsis. / Plants require a variety of elements for their basic biological functions. Interestingly, Transport, assimilation and utilization of these nutrients are not independent of another. However, the biological significance, molecular and genetic bases of these dependencies are not well understood. We use the over-accumulation of inorganic phosphate (Pi) in plants under zinc (Zn) deficiency as an example to dissect a fundamentally and agronomically important Pi-Zn interdependency in Lettuce, rice and Arabidopsis plants. We described the physiological and molecular basis of the interaction between Pi and Zn homeostasis. In Lettuce, we revealed a contrasting behavior between the two lettuce varieties in terms of the coregulation of Pi and Zn homeostasis. In rice, our data reveal coordination between pathways involved in Fe transport and PiZn signaling, which involves the OsPHO1; 1. In Arabidopsis, we discovred a new mecanism that plants use to gate defense and growth process in Pi-Zn dependant manner.