Dissertations / Theses on the topic 'Habitat manipulation and transplantation'

Whilst kidney transplantation is accepted as a cost effective treabnent ofend stage renal failure, the shortage in the kidney donor pool has recently become critical. Historical series ofNHBD renal transplants have been associated with high rates ofallograft failure and dysfunction due to prolonged warm and cold ischaemia. Machine preservation of NHBD kidneys provides a useful tool to test viability pre-transplant and this PhD thesis was directed at improving the existing Newcastle NHBD programme. Newcastle machine preservation is described in which viability criteria is used to reduced primary non function and discard rates. The sequential allograft failures were critically reviewed to develop the new 'IO-point' criteria. Case failures have become a necesSary painful learning experience that allowed improvements in the selection and screening criteria. The long term function ofNHBD renal transplants are presented to illustrate how the function is affected by warm ischaemic injury and delayed graft function. The early dysfunction ofNHBD kidney transplants was found to be temporary and improved with time. Kidney perfusate GST evaluation is an established criteria in the assessment of viability ofNHBD kidneys. In the search for novel biomarkers, perfusate Ala-AP and FABP have been assessed in relation to GST. The novel biomarkers measured a different aspect of allograft injury and comparable results to GST suggest that these could be developed as an adjunct to perfusate GST. The introduction ofstreptokinase pre-flush of the NHBD is illustrated in a porcine and a subsequent human clinical model. The effect on procurement, machine preservation and transplantation has been evaluated. Thrombolytic therapy ofNHB donor facilitated the clearing ofpremorbid intravascular thrombus, thereby improving the preservation and thus the viability of the NHBD kidneys. Allograft dysfunction is a standard feature of ischaemia reperfusion injury. A clinical model ofkidney transplantation is described to illustrate the biochemical and clinical effects of ischaemia reperfusion. An exaggerated response was observed in NHBD kidney transplants that could be attributed to the warm ischaemia insult at time of cardiac arrest.

Trichogramma carverae Oatman and Pinto is mass-released for biological control of the leafroller pest, light brown apple moth, Epiphyas postvittana (Walker) in Australian vineyards. Parasitoid performance can, however, be constrained by a lack of suitable adult food and no information is available on the effect of nectar on the parasitism and longevity of T. carverae. To address this, the effect of alyssum, Lobularia maritima (L.) flowers on E. postvittana parasitism was studied in a vineyard experiment with and without releases of T. carverae. Egg parasitoid activity was assessed with E. postvittana egg �sentinel cards� and no parasitism was recorded in plots without T. carverae releases. Where T. carverae were released, there was no significant enhancement of parasitism by the presence of L. maritima flowers. Three hypotheses were subsequently tested to account for the lack of an effect: (i) T. carverae does not benefit from L. maritima nectar, (ii) T. carverae was feeding on nectar from other flowering plants (weeds) present in the vineyard, (iii) T. carverae was feeding on sugars from ripe grapes. A growth-cabinet experiment using potted L. maritima plants with and without flowers did not support hypothesis one. No parasitism was recorded after day two for T. carverae caged without flowers whilst parasitism occured until day eight in the presence of flowers. A laboratory experiment with common vineyard weeds (Trifolium repens, Hypochoeris radicata, Echium plantagineum) as well as L. maritima did not support hypothesis one but gave partial support to hypothesis two. Survival of T. carverae was enhanced to a small but statistically significant extent in vials with intact flowers of L. maritima, white clover (T. repens) and catsear (H. radicata) but not in vials with flowering shoots of these species from which flowers and flowering buds had been removed. Paterson�s curse (E. plantagineum) flowers had no effect on T. carverae survival. In a laboratory study, punctured grapes significantly enhanced T. carverae survival compared with a treatment without grapes, supporting hypothesis three. Trichogramma carverae performance in the field experiment was probably also constrained by relatively cool and wet weather. Further work on the enhancement of T. carverae efficacy by L. maritima and other carbohydrate sources is warranted. Greenhouse and field experiments were conducted to investigate whether T. carverae benefit from different groundcover plant species. Ten T. carverae adults (<24h after eclosion) were caged with different groundcover species and a control with no plant materials. Epiphyas postvittana egg sentinel cards were used to measure parasitism and longevity was recorded visually. Survival and realised parasitism of T. carverae was significantly higher in L. maritima than in Brassica juncea, Coriandrum sativum, shoots of these species from which flowers had been removed and nil control treatments. A similar experiment with Fagopyrum esculentum (with- and without-flowers) and a control treatment showed that survival was significantly higher in intact F. esculentum than in without-flower and control treatments. There was no significant treatment effect on parasitism in the early stages of that experiment, though parasitism was recorded in the presence of F. esculentum flowers for 12 days, compared with 6 days in other treatments. Higher parasitism was observed in intact Borago officinalis than in the flowerless shoot, water only and no plant material control treatments in a third experiment. There was no significant treatment effect on parasitism. Fitted exponential curves for survival data differed significantly in curvature in the first, second and third experiments but the slope was a non-significant parameter in the second and third experiments. In a second series of laboratory experiments, one male and one female T. carverae were caged with groundcover species to investigate male and female longevity and daily fecundity. Both male and female longevity in F. esculentum and L. maritima treatments were significantly higher than on shoots of these species from which flowers had been removed, and than in the control treatments. Daily fecundity was significantly greater in the intact L. maritima treatment than in all other treatments. Fitted exponential curves for daily fecundity differed significantly in position and slope but not in curvature. There was no significant treatment effect on longevity or parasitism when a male and female were caged with intact B. juncea, B. officinalis or without-flower of these species, nor in the treatment with no plant materials. No parasitism was observed in a survey of naturally occurring egg parasitoids on two sites close to Orange and Canowindra in New South Wales, illustrating the importance of mass releases of T. carverae in biological control of E. postvittana. In an experiment on the Canowindra site, parasitism was significantly higher on day one and day two after T. carverae release when with-flower treatments were compared with without-flower treatments. Parasitism was significantly higher in the F. esculentum treatment than in C. sativum, L. maritima, vegetation without-flowers and control treatments on these dates. On day five, parasitism was higher in C. sativum than in all other treatments. There was no significant increase in parasitism in a second experiment conducted on the Orange site. Coriandrum sativum, F. esculentum and L. maritima appear to be suitable adult food sources for T. carverae and offer some scope for habitat manipulation in vineyards The adults of many parasitoid species require nectar for optimal fitness but very little is known about flower recognition. Flight cage experiments showed that the adults of T. carverae benefited from L. maritima bearing white flowers to a greater extent than was the case for light pink, dark pink or purple flowered cultivars, despite all cultivars producing nectar. Survival and realised parasitism on non-white flowers were no greater than when the parasitoids were caged on L. maritima shoots from which flowers had been removed. The possibility that differences between L. maritima cultivars were due to factors other than flower colour, such as nectar quality, was excluded by dyeing white L. maritima flowers by placing the roots of the plants in 5% food dye (blue or pink) solution. Survival of T. carverae was lower on dyed L. maritima flowers than on undyed white flowers. Mixing the same dyes with honey in a third experiment conducted in the dark showed that the low level of feeding on dyed flowers was unlikely to be the result of olfactory or gustatory cues. Flower colour appears, therefore, to be a critical factor in the choice of plants used to enhance biological control, and is likely to also be a factor in the role parasitoids play in structuring invertebrate communities. Provision of nectar producing plants to increase the effectiveness of biological control is one aspect of habitat manipulation, but care needs to be taken to avoid the use of plant species that may benefit pest species. Greenhouse experiments were conducted to investigate whether the adult E. postvittana and larvae benefit from nectar producing groundcover species. Newly emerged E. postvittana adults were caged with different groundcover species and a honey-based artificial adult diet. The longevity of male and female E. postvittana when caged with shoots of borage (B. officinalis) and buckwheat (F. esculentum) bearing flowers was as long as when fed a honey-based artificial diet. This effect was not evident when caged with shoots of these plants from which flowers had been removed. Longevity was significantly lower than in the artificial diet treatment when caged with coriander (C. sativum) or alyssum (L. maritima) irrespective of whether flowers were present or not. There was no significant treatment effect on the lifetime fecundity of E. postvittana. A second experiment with mustard (B. juncea) (with- and without-flowers), water only and honey-based artificial adult diet showed no significant treatment effects on the longevity of male and female E. postvittana or on the lifetime fecundity of E. postvittana. The anomalous lack of a difference between the water and honey-based diet treatments precludes making conclusions on the value of B. juncea for E. postvittana. Two greenhouse experiments were conducted to evaluate the effects of groundcover species on the larval development of E. postvittana. In the first experiment, larval mortality was significantly higher in C. sativum, and L. maritima than in B. juncea, B. officinalis and white clover (T. repens) a known host of E. postvittana. Coriandrum sativum and L. maritima extended the larval period. In B. juncea and B. officinalis, mortality did not differ from that in T. repens. In F. esculentum, larval mortality was significantly higher than in T. repens. A short larval period was observed on B. juncea, B. officinalis and F. esculentum. Fitted exponential curves for larval mortality differed significantly in curvature between plant treatments. Similarly, successful pupation was significantly lower in C. sativum, F. esculentum and L. maritima than in T. repens. The percentage of successful pupation in B. juncea and B. officinalis did not differ from F. esculentum and T. repens. Fitted exponential curves for pupation differed significantly in curvature. A similar trend was observed in a second experiment with potted plants. The overall results suggest that C. sativum and L. maritima denied benefit to E. postvittana adults and larvae, so could be planted as vineyard groundcover with minimal risk of exacerbating this pest. Overall results suggest that T. carverae require nutrients to reach their full reproductive potential and flowers provide such nutrients. Lobularia maritima and C. sativum may be considered �selective food plants� for T. carverae whereas F. esculentum appears to be a �non-selective food plant�; both T. carverae and E. postvittana benefited from it. Fruits such as grapes can be used as food resources in habitat manipulation and this merits further research. This result also suggests that within species flower colour is an important factor for flower selection in habitat manipulation.

La mucoviscidose peut dans les formes les plus sévères relever d’une transplantation pulmonaire. L’immunosuppression postopératoire et la colonisation en particulier par les champignons placent le patient transplanté pulmonaire pour mucoviscidose (TxPM) à haut risque d’infection fongique opportuniste, notamment aspergillaire. L’arsenal thérapeutique s’est étoffé avec l’arrivée de nouveaux antifongiques (AF) azolés : voriconazole (VRZ) et posaconazole (PSZ). Le VRZ est fortement métabolisé par le cytochrome P450 2C19 et de manière moindre par le CYP3A4 et le CYP2C9. Le VRZ et le PSZ, connus pour être des inhibiteurs du CYP3A4 sont responsables de nombreuses interactions médicamenteuses (IAM), notamment avec les immunosuppresseurs (IS) dont le tacrolimus. L’objectif de ce travail de thèse a été d’identifier les sources de variabilité à l’exposition au VRZ et au PSZ. L’analyse des concentrations résiduelles (C0) d’AF chez 53 patients, traités soit par VRZ (n=35) soit par PSZ (n=17), montre une sous-exposition en AF chez 30% et 65% des patients, respectivement, justifiant le recours à des doses plus élevées que celles recommandées (respectivement +43%, p<0,01 et +35% p<0,0001) et à une combinaison AF. Les patients mutés pour le CYP2C19 requièrent des doses standard d’AF mais ont une variabilité plus importante que les patients non mutés. L’analyse quantitative des IAM montre qu’une réduction des doses de tacrolimus d’un facteur 3 et 4 respectivement avec PSZ et VRZ a été nécessaire. Dans ce contexte d’IAM et de variabilité, un suivi thérapeutique pharmacologique (STP) conjoint (azolé/IS) est incontournable chez le TxPM
Invasive aspergillosis is an emerging problem in immunocompromised patients with a poor prognosis and is particularly serious in patients with cystic fibrosis undergoing lung transplantation (CFLTx). Today the antifungal therapeutic arsenal offers several possibilities for long term oral therapy including azole drugs: voriconazole (VRZ) and posaconazole (PSZ). VRZ is extensively metabolized by the cytochrome isoenzymes (CYP), mainly CYP2C19, and to a lesser extend, CYP3A4 and CYP2C9. VRZ and PSZ are known to be potent inhibitors of CYP3A4 resulting in drug drug interactions (DDI). Targets for such DDI are numerous, but immunosuppressive drugs (IS) are of major concern. The aim of this study is to explore the variability of VRZ and PSZ exposure in CFLTx patients. 53 patients received VRZ (n = 35) and PSZ (n = 17). Analysis of trough concentrations (C0) shows subtherapeutic levels with VRZ (30%) and PSZ (65%) justifying the use of high doses (respectively 43%, p <0. 01 and 35% p <0. 0001). Carriers of the CYP2C19*2 deficient allele require standard VRZ doses but exhibit a higher variability compared with wild type. Quantitative DDI analysis shows that tacrolimus (IS) dose should be decreased by factors of 3 and 4 respectively with PSZ and VRZ. The risk of long underdosed periods, frequently addressed in this population, could justify, on a pharmacokinetic (PK) basis, the need for combination with an exclusive parenteral antifungal while waiting for azole relevant drug level. High PK variability, the risk of low exposure, therapeutic issues and DDI management in CF disease justify close monitoring with systematic combined therapeutic drug monitoring of azole and IS

Paropsis atomaria Olivier (Coleoptera: Chrysomelidae: Paropsini), is a major pest of commercially grown eucalypts in South-East Queensland. Current management of paropsine beetles involves regular inspection and the application of chemical sprays if defoliation is severe. However, non-chemical control of plantation pests is highly desirable given the requirement to certify forest practices for sustainability, and community concerns over the use of pesticides. One way of reducing pesticide use is through conservation biological control, which requires detailed knowledge of the life history of the pest and its natural enemies. This thesis documents aspects of P. atomaria phenology, including life tables, sex ratios and damage estimates; identifies the predators, parasites, and egg and larval parasitoids of P. atomaria; and examines the ecology of the most promising natural enemy, Neopolycystus Girault sp. (Hymenoptera: Pteromalidae) in South-East Queensland. P. atomaria adults are active from September until April and can complete up to four generations in a season. Field mortality between egg and fourth instar larvae is approximately 94%. A large proportion of this mortality can be attributed to natural enemies. The most abundant predators in eucalypt plantations were spiders, comprising 88% of all predators encountered. Egg parasitoids exerted the greatest influence on P. atomaria populations, emerging from around 50% of all egg batches, and were responsible for mortality of almost one third of all eggs in the field. Only about one percent of larvae were parasitised in the field, in contrast to paropsine pests in temperate Australia, where egg parasitism rates are low and larval parasitism rates high. Neopolycystus sp. was the only primary parasitoid reared from P. atomaria eggs, along with three hyperparasitoid species; Baeoanusia albifunicle Girault (Encyrtidae), Neblatticida sp. (Encyrtidae) and Aphaneromella sp. (Platygasteridae). This is the first record of B. albifunicle hyperparasitising Neopolycystus spp. B. albifunicle emerged from one-third of all parasitised egg batches and could pose a potential problem to the efficacy of Neopolycystus sp. as a biological control agent. However, within egg batches, hyperparasitoids rarely killed all Neopolycystus sp. with only 9% of hyperparasitised egg batches failing to produce any primary parasitoids. Total field mortality of P. atomaria through direct and indirect effects of parasitism by Neopolycystus sp. was 28%. The proportion of egg batches parasitised increased with exposure time in the field, but within-batch parasitism rate did not. In general, there was no significant correlation between parasitism rates and distance from landscape features (viz. water sources and native forest).

My research provided new information concerning the management, ecology, and conservation of greater sage-grouse (Centrocercus urophasianus). I report the results of an experiment using strategic intensive sheep grazing to enhance the quality of greater sage-grouse brood-rearing habitat. Although forb cover, an important component of brood-rearing habitat, responded positively to the grazing treatment, the response of other habitat variables was suppressed because the plots were not protected from domestic and wild herbivores during the years following the treatments. Measurements taken in grazing exclosures confirmed that herbivory by both large and small animals had significant impacts on vegetation. However, despite the suppressed habitat response, sage-grouse preferred the treated plots over the controls. In another chapter, I modeled survival rates of sage-grouse chicks to 42-days of age. Average chick survival across my study was high (39%). Survival varied across years and was affected by demographic, behavioral, and habitat factors. The top habitat model indicated that chick survival was positively related to grass cover and was higher in areas dominated by black sagebrush (Artemisia nova) than in big sagebrush (A. tridentata). The top model with demographic/behavioral factors indicated that survival was affected by interactions between hen age and brood mixing as well as between hatch date and brood mixing. In my last chapter I report on a survey of Utah sage-grouse hunter motivations and satisfaction. In 2008 and 2009 I surveyed over 600 sage-grouse hunters in Utah to determine why they chose to apply for sage-grouse hunting permits and what factors contributed to a satisfactory hunting experience. Originally, I had hypothesized that the impending Endangered Species Act listing petition for greater sage-grouse motivated hunters to pursue the species before they lost the opportunity. This hypothesis was not supported by the data. The majority of hunters indicated that they chose to hunt sage-grouse because it was a tradition or because it provided an opportunity to spend time outdoors with family. Additionally, Utah sage-grouse hunter satisfaction was influenced by whether or not the hunter was successful in harvesting at least one bird.

Experiments were conducted to assess whether a concept termed 'attract and reward' (A&R) could enhance conservation biological control (CBC). In A&R, a synthetically-produced herbivore induced plant volatile (HIPV) ('attract') is combined with a floral resource ('reward'). It is anticipated that the two will work synergistically attracting natural enemies into the crop ('attract') and maintaining them within the crop ('reward'). The study system consists of brassica, the most commonly occurring brassica herbivores, their natural enemies and higher order natural enemies. The HIPV deployed is methyl salicylate (MeSA) and the floral resource is buckwheat Fagopyrum esculentum. The aim of the first two field experiments, in 2007 and 2008, was to evaluate the effects of MeSA and MeSA combined with buckwheat (A&R) on the abundance of arthropods from three trophic levels. In 2007, a field experiment was conducted using MeSA alone. The mean abundance of the leafmining fly Scaptomyza flava (trophic level 2), the diamondback moth (trophic level 2)(DBM) parasitoid Diadegma semiclausum (trophic level 2) and the hoverfly Melangyna novaezealandiae (trophic level 3) was increased in MeSA-treatments by up to 300% and for the brown lacewing parasitoid Anacharis zealandica a maximum mean increase of 600% was recorded. Significantly more females of the D. semiclausum and M. novaezealandiae were attracted to MeSA than males. When A&R was deployed in 2008, were arthropods from the third and fourth trophic levels affected. For none of the species was there a synergistic effect between 'attract' and 'reward' on their abundance. The brown lacewing Micromus tasmaniae (trophic level 3), two parasitoids of DBM and one of cabbage white butterfly Pieris rapae (trophic level 2) increased significantly in treatments with buckwheat. The hoverfly Melanostoma fasciatum (trophic level 3) was significantly more abundant in treatments with MeSA, but significantly less abundant in treatments with buckwheat. The effect of MeSA on the fourth trophic level parasitoid Anacharis zealandica (trophic level 4) was inconsistent between years. Here it significantly decreased its abundance, while treatments with buckwheat increased it. Significantly fewer male than female D. semiclausum were attracted to MeSA only treatments. These experiments show that MeSA and buckwheat can have unwanted effects on arthropod abundance which may disrupt CBC. To assess the effect of A&R on CBC a further field experiment evaluating herbivore densities, predation, parasitism and hyper-parasitism rates was conducted. The only effect was significantly higher aphid parasitism in treatments with MeSA. Based on the results from the field experiments it remained unclear whether it was MeSA or a blend of volatiles produced by MeSA-induced host plants that were attractive to the arthropods. An olfactory experiment was conducted to evaluate if the aphid parasitoid Aphidius colemani can be attracted to two different concentrations of MeSA diluted in Synertrol oil. Significantly more parasitoids were attracted to 2.0% MeSA than to air while the parasitoid did not respond to the 0.5% concentration. These results indicate that A&R has potential as a CBC technique, as long as any unwanted side effects can be managed. Although there were no synergistic effects between 'attract' and 'reward' on the abundance of individual natural enemies, combining MeSA and buckwheat could still be beneficial because the two techniques increase the abundance of different natural enemies.

In this study, buckwheat (Fagopyrum esculentum Moench) and alyssum (Lobularia maritima (L.)) flowers were used to examine the effect of floral resources on the efficacy of the leafroller parasitoid Dolichogenidea tasmanica (Cameron) in vineyards. This was done by assessing the influence of these flowers on parasitoid abundance and parasitism rate, and by investigating the consequences of this for leafroller abundance. In laboratory experiments, alyssum flowers were used to investigate the effect of floral food on the longevity, fecundity and sex ratio of D. tasmanica. Dolichogenidea tasmanica comprised more than 95 % of parasitoids reared from field collected leafrollers in this study. The abundance of D. tasmanica during the 1999-2000 growing season was very low compared with previous studies, possibly due to the very low abundance of its leafroller hosts during the experiment. The number of males of this species on yellow sticky traps was increased (although not significantly) when buckwheat flowers were planted in a Marlborough vineyard; however, the number of female D. tasmanica on traps was no greater with flowers than without. The abundance of another leafroller parasitoid, Glyptapanteles demeter (Wilkinson)(Hymenoptera: Braconidae), on traps was also not significantly affected by the presence of buckwheat flowers, although females of this species were caught in greater numbers in the control than in buckwheat plots. Naturally-occurring leafrollers were collected from three vineyard sites in Marlborough, and one in Canterbury during the 2000-2001 season to assess the effect of buckwheat and alyssum flowers on parasitism rate. Parasitism rate more than doubled in the presence of buckwheat at one of the Marlborough vineyards, but alyssum had no effect on parasitism rate in Canterbury. A leafroller release/recover method, used when naturally-occurring leafrollers were too scarce to collect, was unable to detect any effect of buckwheat or alyssum on parasitism rate. Mean parasitism rates of approximately 20 % were common in Marlborough, although rates ranged from 0 % to 45 % across the three vineyard sites in that region. In Canterbury in April, mean parasitism rates were approximately 40 % (Chapter 4). Rates were higher on upper canopy leaves (40-60 %) compared with lower canopy leaves and bunches (0-25 %). Leafroller abundance was apparently not affected by the presence of buckwheat in Marlborough, or alyssum in Canterbury. Buckwheat did, however, significantly reduce the amount of leafroller evidence (webbed leafroller feeding sites on leaves or in bunches) in Marlborough, suggesting that the presence of these flowers may reduce leafroller populations. Leafrollers infested less than 0.1 % of Cabernet Sauvignon leaves throughout the 1999-2000 growing season, but increased in abundance in bunches to infest a maximum of 0.5 % of bunches in late March in Marlborough. In Pinot Noir vines in the 2000-2001 season, leafroller abundance was also low, although sampling was not conducted late in the season when abundance reaches a peak. In Riesling vines in Canterbury, between 1.5 % and 2.5 % of bunches were infested with leafrollers in April. In the laboratory, alyssum flowers significantly increased the longevity and lifetime fecundity of D. tasmanica compared with a no-flower treatment. However, daily fecundity was not increased by the availability of food, suggesting that the greater lifetime fecundity was related to increases in longevity. Parasitoids were also able to obtain nutrients from whitefly honeydew, which resulted in similar longevity and daily fecundity to those when alyssum flowers were present. The availability of food had a significant effect on the offspring sex ratio of D. tasmanica. Parasitoids reared from naturally-occurring leafrollers produced an equal sex ratio, assumed to be the evolutionarily stable strategy (ESS) for this species. In the laboratory, this ESS was observed only when parasitoids had access to alyssum flowers. Without food, or with honeydew only, sex ratios were strongly male-biased. In the field, floral resources affected the sex ratio of D. tasmanica only when this species was reared from leafrollers released and recovered in Marlborough. In that experiment, buckwheat shifted the sex ratio in favour of female production from the equal sex ratio found in control plots. No firm explanations can be given to account for these results, due to a lack of research in this area. Possible mechanisms for the changes in sex ratio with flowers are discussed. This study demonstrated that flowers are an important source of nutrients for D. tasmanica, influencing the longevity, fecundity and offspring sex ratio of this species. However, only some of the field experiments were able to show any positive effect of the provision of floral resources on parasitoid abundance or parasitism rate. More information is needed on the role these parasitoids, and other natural enemies, play in regulating leafroller populations in New Zealand vineyards, and on how they use floral resources in the field, before recommendations can be made regarding the adoption of this technology by growers.

As rising sea temperatures and increases in the frequency, duration, and intensity of marine heatwaves threaten coral survival at a global scale, research on the capacity of corals to acclimatize and adapt to changing environments has become a high priority. Understanding how environmental parameters shape coral thermal performance across habitats is crucial to identify populations with high vulnerability or high thermal tolerance to future ocean warming. In recent studies, corals from high temperature variable environments (HVE) have shown increased thermal tolerance compared to corals from low temperature variable environments (LVE). Here, I investigate if these phenotypes are shaped by acclimatization, habitat-specific adaptation, or a combination of both, in the branching coral, Acropora hemprichii, by reciprocally transplanting individuals between a back (HVE) and front reef (LVE). After ten months of acclimatization, comparisons of photosynthetic efficiency (photosystem II), mortality, and bleaching recovery was assessed for > 2 months between coral ramets following a natural bleaching event in the central Red Sea. In tandem, coral bleaching severity and recovery in each reef environment was assessed to genus level by photographic surveys of fixed belt transects. Bleaching between reef sites was compared against bleaching in treatments to differentiate the role of habitat specific adaptation and acclimatization in the corals. This study aims to elucidate the evolutionary mechanisms driving coral habitat-specific thermal stress tolerances, which may inform coral reef management and restoration efforts.

This dissertation was submitted to the Faculty of Science, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science
Dung beetle feeding is still not a widely understood behaviour. Feeding on the waste of other animals creates a challenge of acquiring the necessary nutrients for growth, development and for survival. Because of their soft mouthparts, it has always been thought that adult dung beetles cannot chew the hard parts of dung but only select smaller particles to feed on. Dung beetle larvae on the other hand can chew harder components, but where they get the nutrients required for development has not yet been discovered. The aim of this study was to discover which dung particles adult dung beetles select when feeding, and when creating a nest for their offspring, and also how much they can alter the dung nutrient content in the process. Foregut and hindgut contents were dissected out of the dung beetle Scarabaeus goryi, and their contents compared with untreated dung from the cow and the excreta of adult beetles. Brood balls and maternal gifts of Euoniticellus intermedius were also dissected. Nitrogen and carbon content, the carbon to nitrogen ratio, and results of the carbon and nitrogen stable isotopes were compared between all samples. When feeding dung beetles selected particles which were bigger than 800 μm in diameter and had three times more nitrogen than raw dung, and used particles over 2000 μm in size in the maternal gift packed for their offspring. Nitrogen content in the selected dung was increased from 1.40 % to 5.14% by adult dung beetle feeding and up to 2.62% in dung selected for the larvae to feed on. The carbon to nitrogen ratio also decreased when feeding adults and in the brood balls made for the larvae to feed on. Both carbon and nitrogen were absorbed from ingested dung during digestion. The heavier nitrogen isotope was selected for when feeding. The heavier nitrogen isotopes and the lighter carbon isotope were selected for during absorption. Dung beetles increase the nitrogen content of the dung on which they feed by careful selection of particles of a certain size and nitrogen content, which is probably the limiting nutrient when feeding and nesting. The increase in the nitrogen content is not only from the change in particle size but also in selection of particles with higher nitrogen content.
MT2018

Spiranthes parksii Correll is an endemic terrestrial orchid to the Post Oak Savannah of East Texas and is currently listed as federally endangered. The construction of Twin Oaks landfill, approximately 20 km east of College Station, TX, will destroy an estimated 379 S. parksii individuals and 44.7 ha of its habitat. Research has been funded to mitigate for this loss and includes documenting demographics, life cycle, local and landscape habitat, and on-site transplantation of S. parksii. Results found that S. parksii was highly variable between years at Twin Oaks and might be due to seasonal rainfall in rosette and early flowering growth. It was also found variable in its production of a rosette and influorescence from year to year. Individual plants were found to occur farther from drainages in higher count years, probably due to soil moisture, although further research should be conducted to confirm this hypothesis. A significant difference (p = 0.026) was found for percent canopy cover > 2 m above 1 m x 1 m quadrats with and without S. parksii, with a mean of 55 percent with S. parksii and 97 percent without S. parksii. A Non-Metric Multidimensional Scaling ordination revealed three different combinations of herbaceous species that occur with S. parksii, which were driven by the presence of three dominant bunch grasses of the Post Oak Savannah: Schizachyrium scoparium, Chasmanthium laxum var. sessiliflorum, and Andropogon ternarius. A close to significant difference (p = 0.07) was found for the leaf litter depth between quadrats with and without S. parksii, with a fewer number of stacked leaves with S. parksii. Analysis of aerial images indicated woody encroachment on Twin Oaks from 1958 to 2004 in areas that have not been mechanically cleared. Additionally, S. parksii was found to persist in an open savannah landscape and likely occurred in the same locations and more widespread in 1958 than are currently found. Transplantation of S. parksii was documented to be successful by a soil-intact method. While a bare-root method showed success with S. cernua, no conclusions can be made of its success for S. parksii due to a low sample size (n = 10).

Le microbiote intestinal équin joue un rôle important dans le maintien de la santé de l'hôte. Le microbiote intestinal est composé de nombreux micro-organismes tels que les bactéries, les virus, les champignons et les archées. Cependant, la majorité de ces cellules microbiennes sont bactériennes, et par conséquent, de nombreuses études, y compris la présente, se concentrent sur l'exploration des communautés bactériennes dans l'intestin. Un déséquilibre du microbiote intestinal, appelé dysbiose, a été observé dans plusieurs conditions, telles que la colite, après l’administration d'antibiotiques ou la modification du régime alimentaire. La restauration du microbiote peut être effectuée par la transplantation de microbiote fécal (FMT). Des études utilisant les recommandations actuelles pour la FMT ont montré une récupération clinique chez les chevaux souffrant de diarrhée, mais le microbiote reste largement inchangé après la FMT et aucune étude randomisée avec contrôle placébo n'a été réalisée. Les hypothèses de ce projet étaient que le traitement avec une FMT concentrée corrigera la dysbiose plus rapidement qu’une FMT conventionnelle et le véhicule, et que le microbiote intestinal des chevaux traités avec une FMT concentrée ressemblera au microbiote intestinal du cheval donneur. L'objectif de ce projet était de développer un protocole pour améliorer la FMT chez les chevaux, en augmentant la concentration de bactéries présentes dans les selles du donneur par centrifugation, et de le tester chez les chevaux atteints de dysbiose intestinale induite par les antibiotiques. L'antibiotique triméthoprime sulfadiazine (TMS) a été administré à neuf chevaux pour induire une dysbiose intestinale. Les chevaux ont été séparés en trois groupes: les chevaux recevant une FMT concentrée (cFMT, n = 3); les chevaux recevant la FMT fraîche (fFMT), selon les recommandations actuelles (n = 3); et les chevaux recevant un véhicule (VEH) avec 10% de glycérol dans une solution saline à 0,9% (n=3). Des échantillons fécaux ont été prélevés avant et après l'administration du TMS, ainsi qu'avant, pendant et après la transplantation. Le séquençage a été réalisé à l'aide de la plateforme Illumina MiSeq et les données analysées à l'aide du logiciel Mothur. Tel qu’attendu, l'antibiotique TMS a significativement diminué la richesse microbienne chez tous les chevaux. De manière inattendue, la composition des suspensions fécales des donneurs cFMT et fFMT était significativement différente de la composition de base des receveurs cFMT et fFMT, respectivement. La composition du microbiote des chevaux ayant reçu une transplantation fécale (concentrée ou non) était significativement différente après la transplantation, alors que ce n’était pas le cas chez les chevaux ayant reçu le véhicule. En outre, l’abondance relative de Escherichia était significativement plus élevée dans les suspensions fécales du donneur cFMT par rapport aux suspensions fécales du donneur fFMT. Les principales limites de ce projet sont la petite taille des groupes et l'exposition des selles des donneurs à l'oxygène et à la congélation-décongélation. En outre, le modèle de dysbiose peut ne pas être optimal pour tester l'efficacité de la FMT, et des études réalisant la FMT chez les chevaux souffrant de diarrhée sont nécessaire. Cette étude a contribué à la recherche de nouvelles approches pour améliorer la FMT chez les chevaux. Le faible effet mesuré avec les deux protocoles de FMT et l’augmentation de Escherichia démontre que les protocoles actuels doivent être optimisés avant de pouvoir recommander la FMT pour traiter et prévenir la dysbiose chez les chevaux.
The equine gut microbiota plays an important role in maintaining the health of the host. The gut microbiota is composed of many microorganisms such as bacteria, viruses, fungi, and archaea. However, the majority of these microbial cells are bacterial cells, and consequently, many studies, including the present one, focus on exploring bacterial communities in the gut. An imbalance of the gut microbiota, termed dysbiosis, has been observed in several conditions such as colitis, colic, after antibiotic administration, or diet modification. Restoration of the gut to a healthy state can be performed through fecal microbiota transplantation (FMT). Studies using current recommendations for FMT have shown clinical recovery in horses with diarrhea, but the microbiota remains largely unchanged after FMT and no controlled studies have been performed. The hypotheses of this project were that treatment with concentrated FMT will correct dysbiosis faster than conventional FMT and the vehicle, and that the gut microbiota of horses treated with concentrated FMT will resemble the gut microbiota of the donor. The objective of this project was to develop an improved protocol for FMT in horses, by increasing the concentration of bacteria found in the donor stool using centrifugation, and to test it in horses with antibiotic-induced intestinal dysbiosis. The antibiotic trimethoprim sulfadiazine (TMS) was administered to nine horses to induce intestinal dysbiosis. Horses were separated into three groups: horses receiving concentrated FMT (cFMT) (n=3); horses receiving fresh FMT (fFMT), as per current recommendations (n=3); horses receiving a vehicle (VEH) with 10% glycerol in 0.9% saline (n=3). Fecal samples were collected before and after antibiotic administration, as well as before, during, and after transplantation. Sequencing was performed using the Illumina MiSeq platform and data analysed using the software Mothur. As expected, the antibiotic TMS significantly decreased the richness in all horses (P < 0.05). Unexpectedly, the membership of the cFMT and fFMT donor fecal suspensions was significantly different from cFMT and fFMT recipients’ baseline membership, respectively. The membership of the cFMT and fFMT recipient horses was significantly different after transplantation, while the vehicle recipients were not. In addition, the Escherichia genus was found in significantly higher relative abundances in the cFMT donor fecal suspensions when compared to the fFMT donor fecal suspensions. The main limitations of this study are the small sample size and exposure of cFMT donor stool to oxygen and freeze-thawing. In addition, the dysbiosis model may not be optimal to test the efficacy of FMT, and studies performing FMT in horses with diarrhea are warranted. This study contributed to the search for novel approaches to improve FMT in horses. The weak effect of both FMT protocols on the gut microbiota and the increase in Escherichia suggest that further clinical studies are needed before FMT can be recommended to treat and prevent dysbiosis in horses.