Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on July 17, 2009. Major professor: Dr. Robert Szlavik. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degrees [of] Master of Science in Engineering, with specialization in Biomedical Engineering, Bachelor's of Science in Electrical Engineering." "June 2009." Includes bibliographical references (p. 22).

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Sanguessugas são importantes componentes da comunidade de macroinvertebrados bentônicos, podendo ser parasitas ou predadoras. Apesar das propriedades terapêuticas relacionadas à secreção salivar destes animais serem conhecidas por milênios, pouca atenção taxonômica foi dada ao grupo, principalmente em regiões como América do Sul, África e Ásia. O objetivo deste trabalho foi de inventariar a hirudofauna parasita da ordem Rhyncobdellida do território brasileiro e aplicar novas técnicas de estudo taxonômico, que não são recorrentes para o grupo. Além das observações da morfologia interna e externa através de dissecções e esteomicroscópio, foi realizado o estudo do tegumento através de microscopia eletrônica de varredura e microtomografia computadorizada para o estudo anatômico. Foram encontradas 7 espécies válidas e 7 espécies novas para a ciência. As ocorrências dos gêneros Oligobdella e Placobdella são discutidas em detalhe e é sugerida a criação de dois novos gêneros, para acomodar as espécies parasitas de Glossiphoniidae bianuladas e trianuladas da América do Sul. O gênero Austrobdella é registrado pela primeira vez para o Atlântico Sul, na costa do Rio de Janeiro / Leeches are important components of the macroinvertebrates community and they have parasitic or predatory behavior. Although the therapeutic properties related to the salivary secretion are known for thousands of years, little attention was given to taxonomic studies, especially in South America, Africa and Asia. The present study aims to explore the diversity of parasitic rhyncobdelid leeches in Brazil and apply new technologies to the taxonomic study of this group. Besides the classic observation on the internal and external morphology using dissection and a stereomicroscope, Scanning Electron Microscopy and Microcomputed tomography were used to access the fine structure of the tegument and the internal morphology, respectively. seven known species and 7 species new to science were found. The occurrences of Oligobdella and Placobdella are discussed and the description of two new genera is suggested, to accommodate biannulate and triannulate parasitic glossiphonid species from South America. The genus Austrobdella is reported for the first time to the Southern Atlantic, from the coast of Rio de Janeiro

Serotonergic Retzius (R) neurons of the leech Hirudo medicinalis in culture reform inhibitory synapses with pressure sensitive (P) neurons while selectively reducing an extrasynaptic, depolarizing response to serotonin (5-HT) in the P neuron. We have examined if the selection of 5-HT responses is restricted to sites of contact between processes and growth cones of these cells. As measured by intracellular recording at the soma, focal application of 5-HT depolarized uncontacted P cell bodies, neurites and growth cones but not processes contacted by R cells. In patch clamp recordings of the depolarizing channels, application of 5-HT modulated channel activity in uncontacted but not in contacted growth cones. The selection of transmitter responses during synaptogenesis is therefore localized to discrete sites of contact specifically between synaptic partners. / Prior experiments have shown that tyrosine kinases play a crucial part in the selection of responses to 5-HT that occurs in the P cell (Catarsi and Drapeau, 1993). To further examine the mechanism responsible for this change in transmitter responses, we have utilized a monoclonal antibody against phosphotyrosine to determine if tyrosine phosphorylation could be detected in P and R cell pairs placed in contact. Our results revealed bright, punctate cytoplasmic staining in P cells paired with R cells. / Embryonic leeches were used to examine how R to P synaptogenesis proceeds in vivo. By filling the R and P neurons with different fluorescent dyes (Lucifer Yellow and Rhodamine-Dextran), confocal microscopy established that putative contact between neuropilar processes were made as early as 11 days of development. Spontaneous, chloride-dependent synaptic potentials in embryonic P cells similar to those seen in adult P cells were observed as early as day 10 of development.

Sanguessugas são importantes componentes da comunidade de macroinvertebrados bentônicos, podendo ser parasitas ou predadoras. Apesar das propriedades terapêuticas relacionadas à secreção salivar destes animais serem conhecidas por milênios, pouca atenção taxonômica foi dada ao grupo, principalmente em regiões como América do Sul, África e Ásia. O objetivo deste trabalho foi de inventariar a hirudofauna parasita da ordem Rhyncobdellida do território brasileiro e aplicar novas técnicas de estudo taxonômico, que não são recorrentes para o grupo. Além das observações da morfologia interna e externa através de dissecções e esteomicroscópio, foi realizado o estudo do tegumento através de microscopia eletrônica de varredura e microtomografia computadorizada para o estudo anatômico. Foram encontradas 7 espécies válidas e 7 espécies novas para a ciência. As ocorrências dos gêneros Oligobdella e Placobdella são discutidas em detalhe e é sugerida a criação de dois novos gêneros, para acomodar as espécies parasitas de Glossiphoniidae bianuladas e trianuladas da América do Sul. O gênero Austrobdella é registrado pela primeira vez para o Atlântico Sul, na costa do Rio de Janeiro / Leeches are important components of the macroinvertebrates community and they have parasitic or predatory behavior. Although the therapeutic properties related to the salivary secretion are known for thousands of years, little attention was given to taxonomic studies, especially in South America, Africa and Asia. The present study aims to explore the diversity of parasitic rhyncobdelid leeches in Brazil and apply new technologies to the taxonomic study of this group. Besides the classic observation on the internal and external morphology using dissection and a stereomicroscope, Scanning Electron Microscopy and Microcomputed tomography were used to access the fine structure of the tegument and the internal morphology, respectively. seven known species and 7 species new to science were found. The occurrences of Oligobdella and Placobdella are discussed and the description of two new genera is suggested, to accommodate biannulate and triannulate parasitic glossiphonid species from South America. The genus Austrobdella is reported for the first time to the Southern Atlantic, from the coast of Rio de Janeiro

No description available.

Clitellate annelids display conserved mechanisms of segmental ectodermal and mesodermal patterning. These tissues are generated by asymmetric divisions of large stem cells called teloblasts, elongating the ectoderm and mesoderm of the embryo. Each teloblast-derived lineage makes highly stereotyped contributions to the leech: the N, O, P, and Q contribute specific neurons, epidermis, and other ectodermal tissues along the ventral-to-dorsal axis of the embryo, respectively. The N and Q ectodermal lineages appear to be specified autonomously, but specification of the O and P lineages depends upon interactions with other, neighboring teloblast lineages. Until quite recently, there have been precious few teloblast lineage-specific markers, and virtually no molecular candidates for genes influencing the proper differentiation of any of these lineages. Here, I explore the possibility that members of the Pax-Six-Eyes absent-Dachshund network are involved in leech ectodermal patterning. I show that the leech Helobdella sp. Austin has two Pax6 paralogs, and demonstrate that Hau-Pax6A is expressed early in a subset of N-derived cells and O-derived cells. Next, I demonstrate that an ortholog of the six gene family, Hau-six1/2a, is expressed in the P lineage. I show through a series of cell ablations that Hau-six1/2a expression is regulated by neighboring teloblasts in a manner consistent with P fate induction, hinting that this transcription factor may be involved in P specification. The identification of these genes is a first step towards dissecting the molecular mechanisms of ectodermal teloblast differentiation in the leech embryo. The evolutionary context of the deployment of these genes is also discussed. In the appendices, I present two projects on the evolution of pigment patterns in Danio rerio and its relatives. In the first, I show that the larval melanin-containing pigment cells of Danio nigrofasciatus are uniquely redeployed into the adult pigment pattern, in contrast to seven related fishes. In the second, I show that variation in yellow pigment cell populations in different danio species may be dependent on variable signaling through the receptor tyrosine kinase fms pathway. / text

Doctor of Philosophy (PhD) / Over 85% of Australia’s population live in urban areas and many turtle populations occur on Australia’s east coast where urban development is particularly concentrated. In the state of NSW, over half of the freshwater coastal wetlands have been highly modified or completely destroyed, and urban freshwater creeks often have only a narrow strip of weedy bushland left along their banks. Even though habitat degradation may result in declines in density and distribution of turtle populations, there are few data on Australian freshwater turtles in urban areas. In addition to extreme habitat alteration, urban waterways are innundated with anthropogenic contaminants from sources including wet weather surface runoff and industrial and sewage discharges. Pollutants can impact all systems of the body with potentially severe effects on reproduction and survival that can result in deterioration of animal populations. Turtles are particularly susceptible to anthropogenic contaminants due to their intimate contact with the aquatic environment, an often high trophic level, their ability to accumulate toxins, and their longevity. For almost all contaminants, the degree of accumulation in and effect on reptile species is unknown. Sublethal effects in field situations are particularly poorly studied and have never been documented in pleurodiran turtles. As a pioneering work in Australian reptile ecotoxicology, this thesis takes a broad approach, but focuses primarily on immunotoxicity and reproductive toxicity – two areas that greatly impact the size and continuance of animal populations. The aim of the thesis is to provide baseline data on haematology, cellular immunology and tissue metal concentrations for freshwater turtles in Sydney – data which were lacking for all Australian turtle species prior to this study. After initial assessment of the distribution and density of freshwater turtles in Sydney, the study examines the potential for Sydney’s turtles as sentinel species for measuring the effects of pollution on haematology, cellular immunity, and parasite loads; and considers the relationships between urban metal pollution and reproductive variables. The relative suitability of non-lethally sampled tissues (blood, carapace, egg) for use in biomonitoring is also assessed. Three species of Australian freshwater turtles were found in the Sydney region, with Chelodina longicollis occurring naturally in the area, and populations of Emydura macquarii and Elseya latisternum likely to have originated from translocated individuals. The North American turtle Trachemys scripta elegans was not encountered during this study despite concerns that it was establishing in the Sydney area. Chelodina longicollis populations were widespread, although poor recruitmment was indicated by low capture rates and comparatively low percentage of juveniles at some sites. Not so widespread, Emydura macquarii was present in much larger numbers than C. longicollis and with a high juvenile component in some areas of southeastern Sydney. I provide information on erythrocyte and leucocyte parameters in C. longicollis over a range of sites, pollution conditions, and seasons. In C. longicollis, numbers of lymphocytes, heterophils and eosinophils varied over sites, but not due to pollution from sewage treatment plant outfalls. There was significant temporal variation in erythrocyte, lymphocyte, eosinophil, heterophil, and basophil number, the heterophil:lymphocyte ratio, and haematocrit, but not consistently among sites. Future studies should ensure simultaneous sampling across sites for comparative purposes. Similarly, turtle populations downstream of sewage treatment plant outfalls showed no consistent difference in number, body condition, blood haemogregarine load, or leech (haemogregarine vector) load from upstream populations. Leech (Helobdella papillornata, with some Placobdella sp.) load and haemogregarine numbers increase dramatically once C. longicollis reach a carapace of 110 mm. The number of leeches on turtles varied across season, year, and site. Turtles with large numbers of leeches had reduced haematocrit, but the presence of leeches had no other correlations with haematological parameters. Haemogregarine numbers did not change across season or year, and were not correlated with haematological variables. The hypothesis that pollutants lead to an increase in normal blood protozoa due to reduced immunity thus was not supported. The concentration of metals in C. longicollis and E. macquarii carapace and in lagoon sediments varied significantly over four urban and four national park sites, but not based on this split. Pollution in periurban areas, such as illegal dumping of toxic wastes and atmospheric deposition of pollutants, means that each site must be classified separately as to degree of metal pollution. There was little or no affect of species, size, sex, or gravidity on metal concentrations in the carapace of adult turtles. Emydura macquarii had higher concentrations of blood Fe than C. longicollis from a different site, but this is possibly due to an increase in haemoglobin resulting from the site’s low aquatic oxygen concentration rather than any increased environmental exposure. Chelid turtles in Sydney do not show much promise as a biomonitoring tool. Carapace analysis is largely discounted as a potential tool for metal biomonitoring due to poor correlations between potentially toxic metals in non-lethally samplable tissues (carapace, claw) and internal organs (liver, kidney) or bone (femur). However, carapace metal concentrations still potentially reflect long-term metal presence or different dietary exposures as evidenced by the significant variation in concentrations over sites. A rare correlation was found for concentrations of aquatic Pb and carapace Pb, and a correlation was also found for concentrations of blood Pb and carapace Pb in E. macquarii. Thus any potential for tissue biomonitoring seems to lie with this highly ecotoxicologically relevant metal. Although two other ecotoxicologically relevent metals, Cu and Se, were significantly higher in egg contents of C. longicollis compared to E. macquarii, these elements are also essential and a lack of baseline values means it is not known if this simply reflects natural taxonomic variation. Ni, a metal of toxicological concern in sea turtles, was not present in egg contents, and only variably present in eggshell. The absence of Pb from eggs, despite its presence in many maternal tissues, suggests that selective metal uptake into eggs may be protective of toxic elements, rather than eggs serving as a maternal method of toxic metal elimination as has been previously suggested. The paucity of toxic metal detection in eggs renders them unlikely tissues for biomonitoring. The maternal tissue or tissues or environmental source from which egg metals originate remains obscure, although a significant negative effect of maternal carapace concentrations of Ca and Mg on eggshell thickness in E. macquarii indicates that there may be mobilisation of Ca and Mg from the carapace for eggshell formation. The only metal whose eggshell concentration correlated with eggshell thickness was Mg, indicating that ecotoxic metals previously associated with eggshell thinning are not problematic in the Sydney chelids. As with North American turtles living at polluted sites, none of the chelid hatchlings were found to have any overt abnormalities. Hatching success was poor and hatching mass low for eggs of both C. longicollis and E. macquarii, although results from natural nests are required to determine whether or not this was an outcome of hormonally-induced oviposition and artificial incubation. It is difficult to interpret metal concentrations found in the soft tissues, calcified tissues, and eggs of chelonians due to the paucity of comparative data, and much more research is required on tissue metal concentrations before patterns will emerge. This especially applies to pleurodires for which no previous information is available. From comparisons with the limited data available for other freshwater turtles, marine turtles, and other aquatic reptiles, it does not appear that Sydney’s turtle populations have unusually high metal concentrations in tissues. Exclusion of toxic metals such as Pb from the egg may also be protective to the developing embryo. An ability to live in polluted habitats, while limiting the accumulation of toxic contaminants, may be one key to their persistence in urban waterways from which other freshwater fauna have disappeared. Reproductive impacts such as low embryo survival and small hatchling weights require more rigorous examination, but may have less effect on these animals which have such naturally high egg and hatchling mortality. Although it was generally hard to demonstrate biochemical, physiological or population impacts of contaminants, C. longicollis from a site with severe sewage pollution did display unusual alterations in a number of haematological variables, body condition, and carapace bone structure. Despite this, the population was large and had a comparatively high ratio of juveniles. Additionally, the adverse haematological alterations appeared reversible. Thus, successful populations in Sydney probably are more dependent on basic ecological needs being met, than on low levels of environmental contaminants. The ongoing persistence of chelid populations in Sydney is likely to be dependent to some extent on their opportunistic diets, which generally make animals less vulnerable to habitat modification and the reduction in prey item diversity following pollution (Mason 1996, Allanson & Georges 1999), with a further benefit possibly bestowed at some sites on E. macquarii by its omnivory.

S'estudia la histologia normal de la paret corporal d'Hirudo medicinalis i els canvis morfogenètics que es donen durant el procés de cicatrització de ferides per incisió, cauterització i nitrat de plata.El procés de curació de ferides a Hirudo medicinalis consta d'una fase de formació d'un tap cel·lular, el pseudoblastema, d'un procés de reepitelització i de la formació d'un teixit cicatricial, com en els altres hirudinis estudiats (Myers, 1935; LeGore i Sparks, 1971; Cornec, 1984). Hem observat també el fenomen de la contracció de la ferida que permet l'acostament dels marges de la ferida.Formació i evolució del pseudoblastemaEl pseudoblastema, a diferència d'altres espècies estudiades, està format per un sol tipus cel·lular: les cèl·lules vasocentrals, provinents del teixit vasofibrós, una especialització del teixit connectiu. Aquestes cèl·lules estan capacitades per realitzar les diferents funcions que en espècies rincobdèl·lides realitzen diferents tipus cel·lulars. En concret: taponament de la ferida a través de la formació del pseudoblastema, fagocitosi dels teixits necrosats i regeneració, almenys d'una part, de la matriu connectiva cicatricial. També són responsables de la contracció de la ferida.Les cèl·lules vasocentrals en el seu estadi de repòs es troben en el teixit vasofibrós formant agrupacions coherents, però sense mostrar unions intercel·lulars especialitzades visibles en ME. La coherència del grup queda assegurada per les interdigitacions entre les cèl·lules vasocentrals i probablement per unions tipus adherens o especialitzades. Les unions amb la matriu són de tipus adherens. Aquestes cèl·lules vasocentrals presenten feixos de filaments d'actina força conspicus.En produir-se una ferida les cèl·lules vasocentrals s'activen, desconnecten les unions intercel·lulars i amb la matriu i migren cap a la zona afectada, on s'acumulen. El pseudoblastema actua com un tap cel·lular que funciona de forma eficient per tancar la ferida en un plaç de temps relativament curt. El pseudoblastema forma un teixit coherent amb unions intercel·lulars tipus adherens, caracteritzades per material electrodens en la cara intracitoplasmàtica, feixos de filaments d'actina que hi convergeixen i espais intercel·lulars petits, de 17-20 mm, atravessats per petites fibril·les.Un cop finalitzat el procés de reepitelització, es produeix una contracció de la ferida. Es produeix per la retracció del pseudoblastema cap a l'interior de l'animal. El pseudoblastema disminueix la seva amplària i arrossega els teixits contigus provocant un tancament. La força motriu que provoca la retracció i l'arrossegament dels teixits vindria donada per la presència dels filaments d'actina a les cèl·lules del pseudoblastema, els quals durant aquesta fase es tornen mes conspicus. La presència d'unions intercel·lulars especialitzades característiques de la fase de contracció, està relacionada amb la transmissió de la força de tensió. Aquestes unions connecten els feixos de filaments d'actina de les cèl·lules amb la matriu o d'una cèl·lula a altre a través d'espais intercel·lulars força amples en els que s'observa material electrodens.ReepitelitzacióL'epitelització s'inicia quan el pseudoblastema està consolidat i segueix el mateix patró que la reepitelització de ferides en epitelis monoestratificats de vertebrats (Stem i DePalma, 1983, és a dir, per migració de tota la capa per sobre del substrat, segons l'anomenat model de lliscament.Les glàndules unicel·lulars mucoses del tegument degeneren abans de produir-se la migració epitelial i posteriorment, un cop consolidat l'epiteli a sobre de la ferida, es diferencien a partir de les cèl·lules epitelials.Durant l'epitelització es produeixen canvis importants en el citosquelet i les unions basals de les cèl·lules epitelials. En canvi, el complex d'unió lateral es manté durant tot el procés. En iniciar-se la migració els tonofilaments es desconnecten dels hemidesmosomes cuticulars i dèrmics i es reagrupen al voltant del nucli, a la vegada que els hemidesmosomes dèrmics es desconnecten de la làmina basal. Un cop acabada la migració, les cèl·lules epitelials estableixen unions basals amb les cèl·lules del pseudoblastema. Aquestes unions no són hemidesmosomes sinó que presenten el mateix aspecte que les unions intercel·lulars del pseudoblastema. Els hemidesmosomes no es tornen a formar fins que les cèl·lules epitelials han restablert la membrana basal.La regeneració de la membrana basal no s'inicia fins que no s'ha començat a regenerar matriu connectiva a la zona cicatricial.Regeneració de la cicatriuAl mateix temps que es dona el fenomen de contracció, s'observa regeneració de la matriu connectiva entre les cèl·lules del pseudoblastema. Aquestes cèl·lules són responsables almenys del recobriment fibrós que presenten en aquest estadi, durant el qual mostren sàculs del reticle endoplasmàtic rugós molt dilatats, característics de cèl·lules que secreten constituents de la matriu. A més, s'observa infiltració de matriu connectiva i processos citoplasmàtics dels fibròcits en els marges del pseudoblastema.En la matriu del teixit connectiu normal s'observen fibres que estan constituïdes per un còrtex de fibril·les col·làgenes organitzades al voltant dels processos citoplasmàtics dels fibròcits. Les fibres del teixit connectiu peridigestiu, d'uns 1,2-1,9 mm de diàmetre, presenten el còrtex prim, amb les fibril·les organitzades paral·lelament a l'eix de la fibra. En canvi, les fibres de la dermis i teixit connectiu intramuscular, d'uns 2,5-7,1 mm de diàmetre, tenen el còrtex gruixut, amb fibril·les que s'organitzen paral·lelament en la zona proximal a la medul·la i de forma desorganitzada en la part més distal.Als 8 mesos la cicatriu encara és detectable. La matriu cicatricial presenta fibres connectives del tipus prim i força material fibril·lar desorganitzat disposat laxament. S'observa colonització per part de fibròcits, cromatòfors, petites fibres musculars i nervis. / This thesis in a study of the morphogenetic events that occurs during wound healing of Hirudo medicinalis and of the normal histology of the body wall.The wound healing process of Hirudo medicinalis involves the formation of a cellular plug, the reepithelialization and the regeneration of a scar tissue, as in the others hirudineans previously studied (Myers, 1935; LeGore and Sparks, 1971; Cornec 1964). We also report the wound contraction process that allows the wound clousure.After a wound is inflicted cells of the connective tissue migrate to form a cellular plug, the pseudoblastema. The pseudoblastema of Hirudo medicinalis formed only by one type of cell: the vasocentral cells. In the resting state those cells are associated with vasofibrous cells forming the vasofibrous tissue.Once the pseudoblastema has been formed, then reepithelialization begins. The epithelium of the wound edges advances as a unified sheet like the monolayered epithelia of Vertebrata (Stenn and DePalma, 1988). Unicellular mucous glands of the integument degenerate until epithelial migration. Later, once the epithelium has been consolidated over the wound, some epithelial cells differentiate into mucous glands.After the wound has been reepithelializated, wound contraction occurs by the retraction of the pseudoblastema.In the later stages, infiltration of fibrocite citoplasmic projections can be observed. The pseudoblastema disintegrates and an extracellular matrix remains in its place. This matrix is colonized by fibrocites, capillary vessels, nerves and little muscular fibers. The body wall muscular fibers sectioned or splitted don't regenerate. The extracellular matrix of the scar zone can be distinguished from the normal one for long periods (8 months at least).An important fact of the work is the role of the vasocentral cells. Those cells are responsible for the formation of the pseudoblastema and for the phagocitosis of the remnants of injures tissue. They are also responsible for the wound contraction, presenting acting filaments alinied with the stress direction and specialized intercellular junctions that transmit tension force. Finally, they contribute to the scar matrix regeneration by the synthesis of a fibrous cell coat.

Doctor of Philosophy (PhD) / Over 85% of Australia’s population live in urban areas and many turtle populations occur on Australia’s east coast where urban development is particularly concentrated. In the state of NSW, over half of the freshwater coastal wetlands have been highly modified or completely destroyed, and urban freshwater creeks often have only a narrow strip of weedy bushland left along their banks. Even though habitat degradation may result in declines in density and distribution of turtle populations, there are few data on Australian freshwater turtles in urban areas. In addition to extreme habitat alteration, urban waterways are innundated with anthropogenic contaminants from sources including wet weather surface runoff and industrial and sewage discharges. Pollutants can impact all systems of the body with potentially severe effects on reproduction and survival that can result in deterioration of animal populations. Turtles are particularly susceptible to anthropogenic contaminants due to their intimate contact with the aquatic environment, an often high trophic level, their ability to accumulate toxins, and their longevity. For almost all contaminants, the degree of accumulation in and effect on reptile species is unknown. Sublethal effects in field situations are particularly poorly studied and have never been documented in pleurodiran turtles. As a pioneering work in Australian reptile ecotoxicology, this thesis takes a broad approach, but focuses primarily on immunotoxicity and reproductive toxicity – two areas that greatly impact the size and continuance of animal populations. The aim of the thesis is to provide baseline data on haematology, cellular immunology and tissue metal concentrations for freshwater turtles in Sydney – data which were lacking for all Australian turtle species prior to this study. After initial assessment of the distribution and density of freshwater turtles in Sydney, the study examines the potential for Sydney’s turtles as sentinel species for measuring the effects of pollution on haematology, cellular immunity, and parasite loads; and considers the relationships between urban metal pollution and reproductive variables. The relative suitability of non-lethally sampled tissues (blood, carapace, egg) for use in biomonitoring is also assessed. Three species of Australian freshwater turtles were found in the Sydney region, with Chelodina longicollis occurring naturally in the area, and populations of Emydura macquarii and Elseya latisternum likely to have originated from translocated individuals. The North American turtle Trachemys scripta elegans was not encountered during this study despite concerns that it was establishing in the Sydney area. Chelodina longicollis populations were widespread, although poor recruitmment was indicated by low capture rates and comparatively low percentage of juveniles at some sites. Not so widespread, Emydura macquarii was present in much larger numbers than C. longicollis and with a high juvenile component in some areas of southeastern Sydney. I provide information on erythrocyte and leucocyte parameters in C. longicollis over a range of sites, pollution conditions, and seasons. In C. longicollis, numbers of lymphocytes, heterophils and eosinophils varied over sites, but not due to pollution from sewage treatment plant outfalls. There was significant temporal variation in erythrocyte, lymphocyte, eosinophil, heterophil, and basophil number, the heterophil:lymphocyte ratio, and haematocrit, but not consistently among sites. Future studies should ensure simultaneous sampling across sites for comparative purposes. Similarly, turtle populations downstream of sewage treatment plant outfalls showed no consistent difference in number, body condition, blood haemogregarine load, or leech (haemogregarine vector) load from upstream populations. Leech (Helobdella papillornata, with some Placobdella sp.) load and haemogregarine numbers increase dramatically once C. longicollis reach a carapace of 110 mm. The number of leeches on turtles varied across season, year, and site. Turtles with large numbers of leeches had reduced haematocrit, but the presence of leeches had no other correlations with haematological parameters. Haemogregarine numbers did not change across season or year, and were not correlated with haematological variables. The hypothesis that pollutants lead to an increase in normal blood protozoa due to reduced immunity thus was not supported. The concentration of metals in C. longicollis and E. macquarii carapace and in lagoon sediments varied significantly over four urban and four national park sites, but not based on this split. Pollution in periurban areas, such as illegal dumping of toxic wastes and atmospheric deposition of pollutants, means that each site must be classified separately as to degree of metal pollution. There was little or no affect of species, size, sex, or gravidity on metal concentrations in the carapace of adult turtles. Emydura macquarii had higher concentrations of blood Fe than C. longicollis from a different site, but this is possibly due to an increase in haemoglobin resulting from the site’s low aquatic oxygen concentration rather than any increased environmental exposure. Chelid turtles in Sydney do not show much promise as a biomonitoring tool. Carapace analysis is largely discounted as a potential tool for metal biomonitoring due to poor correlations between potentially toxic metals in non-lethally samplable tissues (carapace, claw) and internal organs (liver, kidney) or bone (femur). However, carapace metal concentrations still potentially reflect long-term metal presence or different dietary exposures as evidenced by the significant variation in concentrations over sites. A rare correlation was found for concentrations of aquatic Pb and carapace Pb, and a correlation was also found for concentrations of blood Pb and carapace Pb in E. macquarii. Thus any potential for tissue biomonitoring seems to lie with this highly ecotoxicologically relevant metal. Although two other ecotoxicologically relevent metals, Cu and Se, were significantly higher in egg contents of C. longicollis compared to E. macquarii, these elements are also essential and a lack of baseline values means it is not known if this simply reflects natural taxonomic variation. Ni, a metal of toxicological concern in sea turtles, was not present in egg contents, and only variably present in eggshell. The absence of Pb from eggs, despite its presence in many maternal tissues, suggests that selective metal uptake into eggs may be protective of toxic elements, rather than eggs serving as a maternal method of toxic metal elimination as has been previously suggested. The paucity of toxic metal detection in eggs renders them unlikely tissues for biomonitoring. The maternal tissue or tissues or environmental source from which egg metals originate remains obscure, although a significant negative effect of maternal carapace concentrations of Ca and Mg on eggshell thickness in E. macquarii indicates that there may be mobilisation of Ca and Mg from the carapace for eggshell formation. The only metal whose eggshell concentration correlated with eggshell thickness was Mg, indicating that ecotoxic metals previously associated with eggshell thinning are not problematic in the Sydney chelids. As with North American turtles living at polluted sites, none of the chelid hatchlings were found to have any overt abnormalities. Hatching success was poor and hatching mass low for eggs of both C. longicollis and E. macquarii, although results from natural nests are required to determine whether or not this was an outcome of hormonally-induced oviposition and artificial incubation. It is difficult to interpret metal concentrations found in the soft tissues, calcified tissues, and eggs of chelonians due to the paucity of comparative data, and much more research is required on tissue metal concentrations before patterns will emerge. This especially applies to pleurodires for which no previous information is available. From comparisons with the limited data available for other freshwater turtles, marine turtles, and other aquatic reptiles, it does not appear that Sydney’s turtle populations have unusually high metal concentrations in tissues. Exclusion of toxic metals such as Pb from the egg may also be protective to the developing embryo. An ability to live in polluted habitats, while limiting the accumulation of toxic contaminants, may be one key to their persistence in urban waterways from which other freshwater fauna have disappeared. Reproductive impacts such as low embryo survival and small hatchling weights require more rigorous examination, but may have less effect on these animals which have such naturally high egg and hatchling mortality. Although it was generally hard to demonstrate biochemical, physiological or population impacts of contaminants, C. longicollis from a site with severe sewage pollution did display unusual alterations in a number of haematological variables, body condition, and carapace bone structure. Despite this, the population was large and had a comparatively high ratio of juveniles. Additionally, the adverse haematological alterations appeared reversible. Thus, successful populations in Sydney probably are more dependent on basic ecological needs being met, than on low levels of environmental contaminants. The ongoing persistence of chelid populations in Sydney is likely to be dependent to some extent on their opportunistic diets, which generally make animals less vulnerable to habitat modification and the reduction in prey item diversity following pollution (Mason 1996, Allanson & Georges 1999), with a further benefit possibly bestowed at some sites on E. macquarii by its omnivory.