O uso telhados verdes oferece benefícios como: moderação dos valores da temperatura no interior de edificações e contenção temporária da água de chuva, limpeza de poluentes atmosféricos, além de favorecer aspectos ecológicos. Poucos estudos científicos foram realizados no sentido de adaptar as técnicas contemporâneas e a indicação de espécies apropriadas ao sistema de telhado verde extensivo, originadas de regiões de clima temperado para as condições dos climas tropicais. O objetivo desta pesquisa foi identificar espécies com potencial de uso em telhado verde em sistema extensivo, quantificando a reação das plantas à variação de diferentes profundidades de substrato, em situações limitadas de manutenção, no aspecto de irrigação e nutrição do solo. Procurou-se também registrar o comportamento térmico do solo, a fim de verificar a influência da vegetação no aquecimento da parte inferior do solo em relação a distintas profundidades de substrato. Os vegetais foram plantados em setembro de 2009 aplicados em 27 plataformas de teste. Foram cultivadas três espécies de plantas das famílias Fabaceae (Arachis repens Handro), Poaceae (Paspalum notatum Flügge) e Ruscacea (Ophiopogon japonicus (L.F. Ker Gawl)), sob três tratamentos de profundidades de substrato, 0.05, 0.075 e 0.10 m. Quantificou-se mensalmente a porcentagem de cobertura vegetal, crescimento vertical e de sobrevivência, com encerramento ao final de um ciclo anual. O comportamento térmico dos solos nos diferentes tratamentos foi registrado automaticamente por meio de sensores. Os resultados indicaram a espécie Ophiopogon japonicus, em solos de 0.10 m, como a que apresentou o melhor desempenho entre as três examinadas, seguida por Paspalum notatum. Todas as espécies cultivadas em solos de 0.10 m apresentaram resultados satisfatórios quanto a cobertura do solo, crescimento vertical e sobrevivência, em relação ao cultivo em profundidades menores de substrato. O cultivo em menor profundidade de solo (0.05 m) revelou baixo valor de sobrevivência para todas as espécies durante o período de poucas chuvas. O crescimento vertical foi satisfatório para todas as espécies analisadas, dispensando manutenção com poda regular. Os resultados de comportamento térmico indicaram melhor desempenho de solos à profundidade de 0.10 m, independente do tipo de planta cultivado. Concluiu-se que solos de menor espessura são mais dependentes de cobertura vegetal para minimizar seu aquecimento e que os solos de maior espessura o fazem com menor dependência da vegetação. O melhor desempenho térmico foi observado em solos de 0.10 m, em relação às profundidades menores, embora não variasse seu comportamento térmico significativamente com o cultivo das três diferentes espécies de plantas, referente aos valores de cobertura atingidos neste experimento. / The uses of green roofs provide benefits such as moderation of the temperature inside buildings, temporary containment of rainwater, cleaning of air pollutants, in addition to promoting ecological aspects. Few scientific studies have been conducted to adapt contemporary techniques and indication of appropriate species for extensive green roof system, originated from temperate regions to the conditions of tropical climates. The objective of this research was to identify species with potential for use in green roof in the extensive system, quantifying the response of plants to variation of different depths of substrate, in limited situations of maintenance in respect of irrigation and soil nutrition. Was searched register the thermal behavior of soil in order to determine the influence of vegetation on the warming of the lower soil depths for different substrates. The plants were planted in september 2009, applied in 27 platforms. There were three species of cultivated plants of the families Fabaceae (Arachis repens Handro), Poaceae (Paspalum notatum Flügge) and Ruscacea (Ophiopogon japonicus (L.F.) Ker Gawl) under three treatments of substrate depths, 0.05, 0.075 and 0.10 m. Was quantified the percentage of monthly vegetation cover, vertical growth and survival, with closing at the end of an annual cycle. The thermal behavior of soils under different treatments was recorded using sensors. The results indicated that Ophiopogon japonicus in 0.10 m soils, showed the best performance among the three examined. All species grown in 0.10 m of soils had been satisfactory results of soil cover, vertical growth and survival in relation to culture in shallower substrate. The species Arachis repens showed the highest sensitivity to the depth and water stress during the autumn and winter, requiring more necessity of maintenance. Cultivation in shallower soil (0.05 m) showed low survival value for all species during the short rains. The vertical growth was satisfactory for all species analyzed, of which the greatest height reached was Ophiopogon japonicus without requiring regular maintenance pruning. The results indicated better performance thermal behavior of soil to a depth of 0.10 m, regardless of the type of plant grown. It was concluded that soils of lesser thickness are dependent on vegetation cover to minimize your heating, and the soils with more thickness are less dependence on the vegetation. The best thermal performance was observed in soils of 0.10 m compared to shallower depths, but did not vary significantly its thermal behavior with the cultivation of three different species of plants, referring to amounts of coverage achieved in this experiment.

During this PhD project three technical platforms were either improved or newly established in order to identify interesting genes involved in SNF, validate their expression and functionally characterise them. An existing 5.6K cDNA array (Colebatch et al., 2004) was extended to produce the 9.6K LjNEST array, while a second array, the 11.6K LjKDRI array, was also produced. Furthermore, the protocol for array hybridisation was substantially improved (Ott et al., in press). After functional classification of all clones according to the MIPS database and annotation of their corresponding tentative consensus sequence (TIGR) these cDNA arrays were used by several international collaborators and by our group (Krusell et al., 2005; in press). To confirm results obtained from the cDNA array analysis different sets of cDNA pools were generated that facilitate rapid qRT-PCR analysis of candidate gene expression. As stable transformation of Lotus japonicus takes several months, an Agrobacterium rhizogenes transformation system was established in the lab and growth conditions for screening transformants for symbiotic phenotypes were improved. These platforms enable us to identify genes, validate their expression and functionally characterise them in the minimum of time.<br> The resources that I helped to establish, were used in collaboration with other people to characterise several genes like the potassium transporter LjKup and the sulphate transporter LjSst1, that were transcriptionally induced in nodules compared to uninfected roots, in more detail (Desbrosses et al., 2004; Krusell et al., 2005). Another gene that was studied in detail was LjAox1. This gene was identified during cDNA array experiments and detailed expression analysis revealed a strong and early induction of the gene during nodulation with high expression in young nodules which declines with the age of the nodule. Therefore, LjAox1 is an early nodulin. Promoter:gus fusions revealed an LjAox1 expression around the nodule endodermis. The physiological role of LjAox1 is currently being persued via RNAi.<br> Using RNA interference, the synthesis of all symbiotic leghemoglobins was silenced simultaneously in Lotus japonicus. As a result, growth of LbRNAi lines was severely inhibited compared to wild-type plants when plants were grown under symbiotic conditions in the absence of mineral nitrogen. The nodules of these plants were arrested in growth 14 post inoculation and lacked the characteristic pinkish colour. Growing these transgenic plants in conditions where reduced nitrogen is available for the plant led to normal plant growth and development. This demonstrates that leghemoglobins are not required for plant development per se, and proves for the first time that leghemoglobins are indispensable for symbiotic nitrogen fixation. Absence of leghemoglobins in LbRNAi nodules led to significant increases in free-oxygen concentrations throughout the nodules, a decrease in energy status as reflected by the ATP/ADP ratio, and an absence of the bacterial nitrogenase protein. The bacterial population within nodules of LbRNAi plants was slightly reduced. Alterations of plant nitrogen and carbon metabolism in LbRNAi nodules was reflected in changes in amino acid composition and starch deposition (Ott et al., 2005). These data provide strong evidence that nodule leghemoglobins function as oxygen transporters that facilitate high flux rates of oxygen to the sites of respiration at low free oxygen concentrations within the infected cells. / Pflanzen der Ordnung der Leguminosen sind von weltweiter Bedeutung für Landwirtschaft und die allgemeine Nährstoffzusammensetzung von Böden. Die physiologische Besonderheit der Leguminosen liegt in ihrer Fähigkeit begründet, zusammen mit Bakterien, den sogenannten Rhizobien, eine Symbiose einzugehen, im Zuge derer es möglich wird, molekularen Luftstickstoff zu binden. Dieser biochemische Prozess findet in neu gebildeten Pflanzenorganen, den sogenannten Wurzelknöllchen statt.<br> In den Pflanzenwissenschaften werden Gene, die im Zuge der Infektion von Leguminosen mit Rhizobien reguliert werden und für den Entwicklungsprozess der Knöllchen eine wichtige Rolle zu spielen scheinen, als Noduline bezeichnet. Mit Hilfe von sogenannten Hochdurchsatzverfahren ist es in den letzten Jahren möglich geworden, die differentielle Expression von Tausenden von Genen gleichzeitig zu beobachten. Zu diesen Verfahren gehören sogenannte cDNA Arrays. Im Zuge dieser Doktorarbeit wurden die weltweit zweitgrößten cDNA Arrays für die Modell-Leguminose Hornklee (Lotus japonicus), der in unserer Gruppe als Untersuchungsobjekt verwendet wird, entwickelt. Mit Hilfe dieser Methode ist es uns möglich, die Regulation von etwa 15.000 Genen gleichzeitig zu untersuchen. Im Zuge von Untersuchungen, die sich mit der Entwicklung von Wurzelknöllchen in Lotus japonicus beschäftigten wurde ein Nodulin, dessen Existenz früher schon einmal beschrieben wurde, noch einmal bestätigt und die Funktion dieses Genes genauer untersucht. Es kodiert für das Enzym Vitamin C Oxidase, das unter Verwendung von molekularem Sauerstoff reduziertes Vitamin C zu einer anderen Form, dem Dehydroascorbat, oxidiert. Dabei wird Wasserstoffperoxid gebildet. Es konnte gezeigt werden, dass sich die Transkription dieses Gens in infizierten Wurzeln kontinuierlich im Verlauf der Symbiose erhöht, jedoch ist die Transkription in jungen Wurzelknöllchen höher als in alten. Darüber hinaus ist es in nur einer Zellschicht der Wurzelknöllchen, die sehr wichtig für die Entwicklung und tatsächliche Funktion der Knöllchen ist, aktiv. Aus den Beobachtungen kann geschlossen werden, dass dieses Gen eine wichtige Funktion in der Entwicklung der Knöllchen zu spielen scheint und vermutlich zur Zellstreckung und Zellteilung in dieser speziellen Zellschicht beiträgt. In einem zweiten Teil der Arbeit wurde sich einem zweiten und dem wohl wichtigsten Nodulin der Leguminosen, dem Leghämoglobin, gewidmet. Leghämoglobin ist dem menschlichen Blutbestandteil Hämoglobin sehr ähnlich und erfüllt dieselbe Aufgabe: es bindet Sauerstoff. Dieser Prozess ist für Leguminosen von erheblicher Bedeutung, da die bereits beschriebene Fixierung von molekularem Luftstickstoff durch ein bakterielles Enzym katalysiert wird, das extrem sauerstoffempfindlich ist. Leghämoglobine gelten unbestritten als die am besten charakterisierten Einweiße aus Wurzelknöllchen und Wissenschaftler behaupten seit fast 40 Jahren, dass sie essentiell für die Funktion der Knöllchen sind. Doch dies wurde bis jetzt nie bewiesen.<br> Mit Hilfe einer neuen Methode, die die spezifische Bildung von Eiweißen verhindert, war es uns möglich, die Synthese von Leghämoglobin in Lotus japonicus vollkommen zu unterdrücken. In Folge dessen zeigen die transgenen Pflanzen deutliche Nährstoffmangelerscheinungen, wenn sie ohne zusätzlichen Stickstoff aber zusammen mit Rhizobien angezogen werden. Sie können zwar Wurzelknöllchen bilden, jedoch sind diese kleiner und haben nicht die charakteristische rötliche Farbe, die bei unveränderten Pflanzen gefunden wird. Der Phänotyp dieser transgenen Pflanzen wird ganz eindeutig durch ihre Unfähigkeit hervorgerufen, Luftstickstoff fixieren zu können. Der Grund dafür ist das Fehlen des bakteriellen Enzyms, das für die Fixierung verantwortlich ist. Dieser Verlust wird durch erhöhte Sauerstoffgehalte in den Knöllchen verursacht. Außerdem konnten durch weitere Untersuchungen eine der vermuteten Funktionsmechanismen von Leghämoglobin bestätigt werden. Diese hier präsentierten Untersuchungen beweisen erstmalig die jahrzehnte alte Hypothese, dass Leghämoglobine essentiell für die Stickstofffixierung in Leguminosen sind.

O uso telhados verdes oferece benefícios como: moderação dos valores da temperatura no interior de edificações e contenção temporária da água de chuva, limpeza de poluentes atmosféricos, além de favorecer aspectos ecológicos. Poucos estudos científicos foram realizados no sentido de adaptar as técnicas contemporâneas e a indicação de espécies apropriadas ao sistema de telhado verde extensivo, originadas de regiões de clima temperado para as condições dos climas tropicais. O objetivo desta pesquisa foi identificar espécies com potencial de uso em telhado verde em sistema extensivo, quantificando a reação das plantas à variação de diferentes profundidades de substrato, em situações limitadas de manutenção, no aspecto de irrigação e nutrição do solo. Procurou-se também registrar o comportamento térmico do solo, a fim de verificar a influência da vegetação no aquecimento da parte inferior do solo em relação a distintas profundidades de substrato. Os vegetais foram plantados em setembro de 2009 aplicados em 27 plataformas de teste. Foram cultivadas três espécies de plantas das famílias Fabaceae (Arachis repens Handro), Poaceae (Paspalum notatum Flügge) e Ruscacea (Ophiopogon japonicus (L.F. Ker Gawl)), sob três tratamentos de profundidades de substrato, 0.05, 0.075 e 0.10 m. Quantificou-se mensalmente a porcentagem de cobertura vegetal, crescimento vertical e de sobrevivência, com encerramento ao final de um ciclo anual. O comportamento térmico dos solos nos diferentes tratamentos foi registrado automaticamente por meio de sensores. Os resultados indicaram a espécie Ophiopogon japonicus, em solos de 0.10 m, como a que apresentou o melhor desempenho entre as três examinadas, seguida por Paspalum notatum. Todas as espécies cultivadas em solos de 0.10 m apresentaram resultados satisfatórios quanto a cobertura do solo, crescimento vertical e sobrevivência, em relação ao cultivo em profundidades menores de substrato. O cultivo em menor profundidade de solo (0.05 m) revelou baixo valor de sobrevivência para todas as espécies durante o período de poucas chuvas. O crescimento vertical foi satisfatório para todas as espécies analisadas, dispensando manutenção com poda regular. Os resultados de comportamento térmico indicaram melhor desempenho de solos à profundidade de 0.10 m, independente do tipo de planta cultivado. Concluiu-se que solos de menor espessura são mais dependentes de cobertura vegetal para minimizar seu aquecimento e que os solos de maior espessura o fazem com menor dependência da vegetação. O melhor desempenho térmico foi observado em solos de 0.10 m, em relação às profundidades menores, embora não variasse seu comportamento térmico significativamente com o cultivo das três diferentes espécies de plantas, referente aos valores de cobertura atingidos neste experimento. / The uses of green roofs provide benefits such as moderation of the temperature inside buildings, temporary containment of rainwater, cleaning of air pollutants, in addition to promoting ecological aspects. Few scientific studies have been conducted to adapt contemporary techniques and indication of appropriate species for extensive green roof system, originated from temperate regions to the conditions of tropical climates. The objective of this research was to identify species with potential for use in green roof in the extensive system, quantifying the response of plants to variation of different depths of substrate, in limited situations of maintenance in respect of irrigation and soil nutrition. Was searched register the thermal behavior of soil in order to determine the influence of vegetation on the warming of the lower soil depths for different substrates. The plants were planted in september 2009, applied in 27 platforms. There were three species of cultivated plants of the families Fabaceae (Arachis repens Handro), Poaceae (Paspalum notatum Flügge) and Ruscacea (Ophiopogon japonicus (L.F.) Ker Gawl) under three treatments of substrate depths, 0.05, 0.075 and 0.10 m. Was quantified the percentage of monthly vegetation cover, vertical growth and survival, with closing at the end of an annual cycle. The thermal behavior of soils under different treatments was recorded using sensors. The results indicated that Ophiopogon japonicus in 0.10 m soils, showed the best performance among the three examined. All species grown in 0.10 m of soils had been satisfactory results of soil cover, vertical growth and survival in relation to culture in shallower substrate. The species Arachis repens showed the highest sensitivity to the depth and water stress during the autumn and winter, requiring more necessity of maintenance. Cultivation in shallower soil (0.05 m) showed low survival value for all species during the short rains. The vertical growth was satisfactory for all species analyzed, of which the greatest height reached was Ophiopogon japonicus without requiring regular maintenance pruning. The results indicated better performance thermal behavior of soil to a depth of 0.10 m, regardless of the type of plant grown. It was concluded that soils of lesser thickness are dependent on vegetation cover to minimize your heating, and the soils with more thickness are less dependence on the vegetation. The best thermal performance was observed in soils of 0.10 m compared to shallower depths, but did not vary significantly its thermal behavior with the cultivation of three different species of plants, referring to amounts of coverage achieved in this experiment.

En la presente tesis se estudió la factibilidad de caracterizar y modelar la tecnología de ahumado aplicada a una especie pesquera pelágica de Argentina, buscando a partir de las experiencias realizadas obtener un producto de alta calidad final. Se trabajó sobre la especie Scomber japonicus, teleósteo de acuerdo a la clasificación científica por tener un esqueleto óseo, por su tipo de hábitat marino se considera pelágico y por su contenido lipídico una especie grasa. Aproximadamente el 76% de las capturas en el Océano Atlántico Sudoccidental, donde se ubican los principales puertos de Argentina, están destinadas a su elaboración como conserva, siendo apreciada por la excelencia del producto que se obtiene. El porcentaje restante se exporta como pescado entero congelado, siendo, por lo tanto este producto y la conserva, los dos productos que se elaboran en Argentina con esta especie. Las estadísticas indican la posibilidad de expansión del mercado incluyendo productos diferentes. Es por ello que la aplicación de tecnologías tradicionales de procesamiento de pescado, como es el ahumado, se presentan como alternativas para el desarrollo de productos alimenticios de alta calidad nutricional. El presente trabajo de tesis fue desarrollado en la ciudad de Mar del Plata, caracterizada por su actividad portuaria permitiendo la disposición del recurso pesquero, de infraestructura y equipos para realizarla, con el objetivo de transferir a la industria los conocimientos aportados por el mismo. En este contexto, se analizaron experimentalmente las distintas etapas que componen el proceso de ahumado sobre la especie, desde la materia prima hasta el producto final listo para consumir, considerando tanto los aspectos fisicoquímicos y nutricionales como sensoriales y microbiológicos implicados.

The influence of forest canopy disturbance (FCD) on La Crosse virus (LACV), leading cause of US pediatric arboviral encephalitis, is critical to understand in landscapes where forests are periodically harvested. Southwestern Virginia is part of an emerging focus of this interior forest bunyavirus. I investigated how the temperate forest mosquito community, LACV vectors, and the LACV amplifying vertebrate host (chipmunks) were impacted by logging. This research was conducted across an experimental FCD gradient (from least to most disturbed: contiguous control, fragmented control, clearcut, and high-leave shelterwood (SW)). Using gravid traps, I found that the mosquito community was resilient to logging with no significant difference in diversity or community composition across treatments. Mean number of female mosquitoes caught per trap-night declined with disturbance. FCD significantly affected the abundance of vector species in different ways. The primary LACV vector, Aedes triseriatus, and the recent invasive Ae. japonicus declined with logging. Other vectors (Ae. albopictus, Ae. canadensis, and Ae. vexans) thrived with logging. Culex pipiens/restuans was affected by disturbance but had no treatment preference. A mark-recapture study revealed that chipmunk abundance and LACV seroprevalence were greatest on the SW. In sync with Ae. triseriatus abundance but in contrast to the chipmunk results, mosquito LACV detection was significantly greater on unlogged sites. Surprisingly, LACV was detected in Ae. japonicus and Cx. pipiens/restuans. In a follow-up study, I isolated LACV from field-collected Ae. japonicus. Although LACV was previously isolated from Cx. pipiens, the vector competence was unknown. Therefore, I examined the vector competence of Cx. pipiens and Cx. restuans. Although poor vectors, I did detect LACV in the saliva of both species. An additional experiment found that nutritionally-stressed Cx. restuans were better vectors than those in the control group, indicating that environmental stressors (e.g., FCD) may alter the ability of accessory vectors to spread LACV. The influence of FCD on LACV is complex. Because logging decreases Ae. triseriatus abundance, human LACV risk is likely lowered by decreased transovarial vertical transmission. However, high chipmunk seroprevalence on disturbed sites suggest horizontal transmission with accessory vectors plays a larger role in LACV risk on recently logged sites. / Ph. D.

Mosquitoes are the deadliest animal on the planet killing about a million people a year. These insects are competent vectors of multiple pathogens (e.g., Plasmodium sp, filarial worms, and arboviruses). In most species, females are blood feeders, and must consume a blood meal to complete a gonotrophic cycle. Extensive research has been conducted on hematophagy and host-seeking behaviors, but relatively little is known about phytophagy. Sugar feeding is an essential aspect of mosquito biology. Both male and female mosquitoes must consume sugar as a primary fuel source. Mosquitoes use olfactory and visual cues among other cues to find suitable food sources. Abiotic factors, such as temperature and humidity, have been shown to impact mosquito behaviors, including sugar feeding. Recently, sugar feeding has been identified as a promising control target for multiple species of mosquitoes. Attractive toxic sugar baits (ATSBs) attract both male and females through the use of plant derived volatiles. In this work, we first examined the effects of temperature and humidity on the survival of sugar fed Aedes aegypti. We showed that sugar feeding greatly increases longevity in optimal conditions and that humidity impacted survival while temperature less so. Second, we aimed at developing an ATSB for controlling Aedes j. japonicus mosquitoes. Overall, this work sheds light on the importance of abiotic factors and sugar feeding on mosquito survival and lays the groundwork for controlling an invasive mosquito species. / Master of Science in Life Sciences / Mosquitoes are the deadliest organisms on the planet killing about a million people each year due to the multitude of pathogens they may transmit (e.g., malaria parasites, Zika virus, dengue virus). Female mosquitoes transmit pathogens by taking blood meals to obtain essential nutrients needed to develop eggs. If knowledge on host-seeking behavior and blood-feeding is extensive, comparatively less is known about sugar feeding. Sugar feeding is an important behavior displayed by both male and female mosquitoes to obtain energy for flying, reproduction, and survival. Mosquitoes feed on a variety of sugar sources including plant nectar and decaying fruits. They use multiple different cues in order to locate suitable meals including olfaction and vision. Environmental factors such as temperature and humidity affect mosquito activity, dehydration, and sugar feeding. In the present work, we first examined the effects of temperature and humidity on survival in the major disease vector species, Aedes aegypti. As the global temperatures are increasing, it is essential to better understand how mosquitoes adapt and deal with environmental stressors in a changing world. We then aimed at exploiting sugar feeding behavior by developing a novel method of control for another invasive mosquito species, Aedes j. japonicus. Together, these results help us have a better understanding of mosquito biology and ecology which is crucial for predicting future distribution of invasive species and designing new control strategies.

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Thesis (Ph. D. (Ichthyology and Fisheries Science))--Rhodes University, 2006.

Zika (ZIKV), La Crosse (LACV), and Cache Valley (CVV) viruses are mosquito-vectored diseases that cause significant morbidity and mortality in humans and animals. Transmission of these viruses are dependent on numerous factors including vector competence and the effects of mosquito-virus interactions. We conducted vector competence studies of local Aedes and Culex mosquitoes for ZIKV and CVV, and found that all Aedes mosquitoes were competent for CVV and only Aedes albopictus and Aedes japonicus were competent for ZIKV. Vector competence for CVV was dose-dependent, where mosquitoes orally infected with high titers developed higher transmission rates. We also found that vector competence for ZIKV was limited by midgut and salivary gland barriers. Second, we looked at the effects of LACV and ZIKV infection on repellent response in Aedes mosquitoes and found that infected mosquitoes were refractory to low concentrations of DEET, picaridin, and PMD. Increasing concentrations of the repellents to ≥10% was able to increase percent protection (%p) against infected and uninfected mosquitoes. Lastly, we determined the effects of ZIKV and LACV infection on oxidative stress and glutathione-S-transferase (GST) activity in Aedes albopictus. Virus infection had no effect on oxidative stress, but GST activity was significantly different for mosquitoes 3-days post-exposure. We found that oxidative stress levels and GST activity had an inverse relationship for infected and uninfected mosquitoes, where oxidative stress decreased and GST activity increased over the 10-day test period. This indicates that GSTs may aid in controlling byproducts of oxidative stress. The results from this entire study identified competent vectors for emerging arboviruses and demonstrated the behavioral and physiological effects of virus infection in the mosquito vector. / Doctor of Philosophy / Zika (ZIKV), La Crosse (LACV), and Cache Valley (CVV) viruses are transmitted by mosquitoes and can make humans and animals very sick. There are many biological factors that determine if a mosquito can transmit a virus and these viruses can change the biology of a mosquito. We conducted laboratory studies to see if Aedes and Culex mosquitoes can transmit ZIKV and CVV. We found that all Aedes mosquitoes were able to transmit CVV and only the Asian tiger mosquito and Asian rock pool mosquito were able to transmit ZIKV. Mosquitoes infected with high amounts of CVV developed higher transmission rates. We also found that transmission of ZIKV was limited by barriers in the mosquito midgut and salivary glands. Second, we looked at the effects of LACV and ZIKV infection on how Aedes mosquitoes respond to repellents and found that infected mosquitoes were less sensitive to low concentrations of DEET, picaridin, and PMD. Increasing concentrations of the repellents to 10% or higher was able to provide adequate protection against infected and uninfected mosquitoes. Lastly, we determined the effects of ZIKV and LACV infection on oxidative stress and glutathione-S-transferase (GST) activity in the Asian tiger mosquito. Virus infection did not change oxidative stress, but GST activity was higher in infected mosquitoes tested after 3 days after infection. We found that oxidative stress decreased and GST activity increased over the 10-day test period. This indicates that GSTs may help control damaging products from oxidative stress. The results from this entire study identified what mosquitoes were able to transmit emerging mosquito-borne viruses and demonstrated the biological effects of virus infection in the mosquitoes.