Antimicrobial optimization procedures use the most resistant bacterial culture that could be present in the food to determine the levels of treatment needed to ensure safety. These procedures usually only focus on one method of preparing these inoculums for testing despite prior research showing that the preparation of the culture can influence how the culture reacts to a treatment. In this work, planktonic cells grown in a liquid media and sessile cells grown on a similar solid media were subjected to identical emulsion based antimicrobial systems. The cultures were monitored over time and their numbers periodically enumerated. Weibullian destruction models were used to characterize bacterial death and the different inoculum preparations were separated using ANOVA statistical tests. Using these models highly significant differences between the different sessile and planktonic methods of growth were found. This difference was also found to not be related to the production of curli used in biofilm formation. These results suggest that the methods of inoculum preparation can be a significant factor in bacterial survival, a factor that should be included in food antimicrobial optimization procedures.

Made available in DSpace on 2017-07-10T19:24:21Z (GMT). No. of bitstreams: 1 Josean_eBortolini.pdf: 1601181 bytes, checksum: 580412a5072cf9180422761979281cff (MD5) Previous issue date: 2016-02-12 / The increasing population development has contributed to a significant increase in consumption and consequently poultry production, which results in a larger waste generation, since poultry litter receives excreta. One of the alternatives to treat waste and find a final disposal to it in this trial is the anaerobic digestion of poultry litter (PL), which not only generates bio-fertilizer, but also produces biogas. However, digester starting as well as quality and quantity of generated biogas are associated to the material to be digested and with the same operating conditions, since they are factors for inocula application. Thus, this study aimed to investigate the influence of digestate application as inoculum at anaerobic digestion from poultry litter. Firstly, specific biomethanogenic potential tests were carried out from poultry litter and there was a test to check if the digestate use as inocula has influenced on biogas production. Finally, this trial was carried out and inocula were tested (beef and swine digestate) during anaerobic digestion process of poultry litter, with daily diet, according to the volumetric loads that were tested - 0.67; 1.00; and 1.67 gSV.L-1day-1. It was concluded that poultry litter can be used as substrate in anaerobic digestion process and that digestate application as inoculum has shown adequate results regarding biogas production, since the treatment without inoculum addition showed the lowest biogas answers. So, when the inocula were compared with one another (beef and swine digestate), it was concluded that both of them are indicated in the digestion process with poultry litter. However, bovine inoculum showed the highest values of biogas and methane production, and also the lowest values in relation to the percentages of neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin (LIG), highlighting the advantages of its use as inoculum due to its greater capacity to degrade fibrous fractions. / O crescente aumento populacional contribui para o relevante aumento de consumo e consequentemente de produção de frangos, o qual acarreta maior geração de resíduos, pois a cama de aviário recebe as excretas. Uma das alternativas para o tratamento do resíduo e destinação final abordada neste trabalho é a digestão anaeróbia da cama de aviário (CA), que além de gerar o biofertilizante, produz o biogás. No entanto, tanto a partida do biodigestor como a qualidade e quantidade do biogás gerado estão relacionadas com o material a ser digerido e com as condições de operação do mesmo, os quais são fatores para a utilização de inóculo. Assim, o presente estudo teve como objetivo geral investigar a influência de aplicação de digestato como inóculos na biodigestão anaeróbia da cama de aviário. Para isso, inicialmente, foram realizados testes de potencial biometanogênico específico da cama de aviário e teste para verificar se o uso de digestato como inóculo influenciava a produção de biogás. Por fim, realizou-se o experimento e os inóculos foram testados (digestatos bovino e suíno) no processo de biodigestão anaeróbia da cama de aviário, com alimentação diária, conforme as cargas volumétricas testadas - 0,67; 1,00; e 1,67 gSV.L-1dia-1. Foi possível concluir que a cama de aviário pode ser utilizada como substrato no processo de biodigestão anaeróbia, assim como a utilização de digestato como inóculo apresentou resultados satisfatórios em relação à produção de biogás, uma vez que o tratamento sem adição de inóculo apresentou a menor média de produção de biogás. Em relação à comparação entre os inóculos, (digestato bovino e suíno), foi possível concluir que ambos são indicados no processo de biodigestão com cama de aviário. Contudo, o inóculo bovino apresentou os maiores valores em relação à produção de biogás e metano, e os menores valores em relação às porcentagens de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e lignina (LIG), evidenciando as vantagens de sua utilização como inóculo em função de sua maior capacidade na degradação das frações fibrosas.

Made available in DSpace on 2017-05-12T14:47:37Z (GMT). No. of bitstreams: 1 Josean_eBortolini.pdf: 1601181 bytes, checksum: 580412a5072cf9180422761979281cff (MD5) Previous issue date: 2016-02-12 / The increasing population development has contributed to a significant increase in consumption and consequently poultry production, which results in a larger waste generation, since poultry litter receives excreta. One of the alternatives to treat waste and find a final disposal to it in this trial is the anaerobic digestion of poultry litter (PL), which not only generates bio-fertilizer, but also produces biogas. However, digester starting as well as quality and quantity of generated biogas are associated to the material to be digested and with the same operating conditions, since they are factors for inocula application. Thus, this study aimed to investigate the influence of digestate application as inoculum at anaerobic digestion from poultry litter. Firstly, specific biomethanogenic potential tests were carried out from poultry litter and there was a test to check if the digestate use as inocula has influenced on biogas production. Finally, this trial was carried out and inocula were tested (beef and swine digestate) during anaerobic digestion process of poultry litter, with daily diet, according to the volumetric loads that were tested - 0.67; 1.00; and 1.67 gSV.L-1day-1. It was concluded that poultry litter can be used as substrate in anaerobic digestion process and that digestate application as inoculum has shown adequate results regarding biogas production, since the treatment without inoculum addition showed the lowest biogas answers. So, when the inocula were compared with one another (beef and swine digestate), it was concluded that both of them are indicated in the digestion process with poultry litter. However, bovine inoculum showed the highest values of biogas and methane production, and also the lowest values in relation to the percentages of neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin (LIG), highlighting the advantages of its use as inoculum due to its greater capacity to degrade fibrous fractions. / O crescente aumento populacional contribui para o relevante aumento de consumo e consequentemente de produção de frangos, o qual acarreta maior geração de resíduos, pois a cama de aviário recebe as excretas. Uma das alternativas para o tratamento do resíduo e destinação final abordada neste trabalho é a digestão anaeróbia da cama de aviário (CA), que além de gerar o biofertilizante, produz o biogás. No entanto, tanto a partida do biodigestor como a qualidade e quantidade do biogás gerado estão relacionadas com o material a ser digerido e com as condições de operação do mesmo, os quais são fatores para a utilização de inóculo. Assim, o presente estudo teve como objetivo geral investigar a influência de aplicação de digestato como inóculos na biodigestão anaeróbia da cama de aviário. Para isso, inicialmente, foram realizados testes de potencial biometanogênico específico da cama de aviário e teste para verificar se o uso de digestato como inóculo influenciava a produção de biogás. Por fim, realizou-se o experimento e os inóculos foram testados (digestatos bovino e suíno) no processo de biodigestão anaeróbia da cama de aviário, com alimentação diária, conforme as cargas volumétricas testadas - 0,67; 1,00; e 1,67 gSV.L-1dia-1. Foi possível concluir que a cama de aviário pode ser utilizada como substrato no processo de biodigestão anaeróbia, assim como a utilização de digestato como inóculo apresentou resultados satisfatórios em relação à produção de biogás, uma vez que o tratamento sem adição de inóculo apresentou a menor média de produção de biogás. Em relação à comparação entre os inóculos, (digestato bovino e suíno), foi possível concluir que ambos são indicados no processo de biodigestão com cama de aviário. Contudo, o inóculo bovino apresentou os maiores valores em relação à produção de biogás e metano, e os menores valores em relação às porcentagens de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e lignina (LIG), evidenciando as vantagens de sua utilização como inóculo em função de sua maior capacidade na degradação das frações fibrosas.

Le blé (genre Tritucum aestivum, famille des Poaceae) est une céréale d’intérêtagronomique très important. Certaines variétés très anciennes sont mise de côté pour desvariétés plus récentes souvent sélectionnées pour répondre à une culture intensiveconsommatrice de produits phytosanitaires. L’agriculture biologique, système de productionsupposant une réduction des intrants chimiques de synthèse afin de préserver l’écosystème,peut se définir comme une pratique où l’emploi d’engrais synthétiques, de pesticideschimiques et d’organismes génétiquement modifiés est prohibé.Cette pratique gagne de plus en plus en popularité et la superficie des terres cultivéesde cette manière a crû de 60 % entre 2000 et 2004, sur la planète. Les contraintes associées àla production de céréales biologiques comprennent la baisse de rendement attribuable auxcarences d’éléments nutritifs dans le sol et la concurrence des mauvaises herbes. Au cours des90 dernières années, les efforts internationaux d’amélioration du blé se sont concentrés sur lahausse du rendement et les paramètres de qualité.La mise en place d’une base de données des blé basées sur des critèresmorphologiques, taxonomiques et écologiques et l'introduction des mycorhizes à arbuscules(MA), connues pour aider à la sélection et induire une augmentation de rendement et dequalité de la production, dans l'optique de produire plus dans une agriculture respectueuse del’environnement pourrait constituer une partie intégrante d'une stratégie appropriée.Cependant, les effets mycorhiziens sur les rendement et la qualité de la production ne sont pastoujours prévisibles et les mécanismes qui régulent ces paramètres qualitatifs des mycorhizessont largement inconnus.Le criblage au champ de 53 variétés de blés anciens a montré des différences dans leuraptitude à développer des mycorhizes avec des champignons indigènes. Des plantesanalysées, seul cinq variétés étaient toutes mycorhizées au Tallage, alors que toutes l’étaientau stade Epiaison. Au stade Maturation des épis, dix-neuf variétés montraient une diminutionde la mycorhization.L’inoculation avec un inoculum de laboratoire lors de l’expérimentation en serre dansdes pots contenant d’une part leur terre habituelle de culture et de l’autre la terre d’Epoisses4montre, qu’ avec cet inoculum, toutes les variétés de blé se mycorhizent. Pour les variétéstestées, les variétés récentes utilisées en agriculture biologique mycorhizent mieux que lesanciennes, mais l’effet mycorhizien sur le rendement est observé uniquement chez desvariétés anciennes de blé. Démontrant ainsi un effet variétal sur le développement etl’expression de la symbiose. Les bénéfices de la symbiose sont plus accentués au niveau desphénomènes qualitatifs à savoir la viabilité des grains.L’apport d’un inoculum commercial lors d’expérimentation en serre dans des potcontenant le même sol, a modifié ces proportions. Cet inoculum a également permisl’amélioration du développement des blés et la qualité des graines de certaines variétésdémontrant à la fois l’importance du génome de la plante dans l’expression bénéfique de lasymbiose et de l’impossibilité des champignons mycorhizogènes indigènes à assurer ledéveloppement optimal de la symbiose. Au champ, l’effet variétal a été confirmé suite àl’apport d’un inoculum commercial ou, à l’exception d’une variété, l’inoculation a permis uneamélioration du rendement, particulièrement sensible chez la variété qui a été la plusproductive, soulignant l’intérêt qu’il y aurait à développer un projet de croisement pouraugmenter la réponse des blés aux mycorhizes. / Wheat (kind Tritucum aestivum, Poaceae family) is a very important cereal ofagronomic interest. Some very ancient varieties are set aside for recent varieties often selected to meet a consumer intensive cultivation of pesticides. Organic farming production system assuming a reduction of synthetic chemical inputs in order to preserve the ecosystem can be defined as a practice where the use of synthetic fertilizers, chemical pesticides and genetically modified organisms is prohibited. This practice is gaining more and more popularity and the amount of land cultivated in this way has increased by 60% between 2000 and 2004. Constraints associated with the production of organic grains include lower yields due to nutrient deficiencies in the soil and weed competition. During the past 90 years, the international efforts in wheat breeding have focused on increasing yield and quality parameters The establishment of a wheat database based on morphological, taxonomic and ecological criteria and the introduction of arbuscular mycorrhizal (AM), known to help in the selection and induce an increase in yield and quality of production with a perspective to increase production in an agriculture that respects the environment, could be an integral part of an appropriate strategy. However, mycorrhizal effects on yield and quality of production are not always predictable and the mechanisms that regulate these qualitative parameters are largely unknown. Field screening of 53 ancient wheat varieties showed differences in their ability to interact with endogenous mycorrhizal fungi. Among the analysed plants, only five varieties were mycorrhized for all samples at tillering. All samples were mycorrhized at the heading stage for all varieties. Nineteen showed a decrease in the number of mycorrhized samples at the ears maturity. Inoculation with a laboratory inoculum during a greenhouse experiments in pots, containing either the wheat field soil or Ò EpoissesÓ soil, showed that all wheat varieties form mycorrhizal symbiosis. Between varieties tested, recent wheat varieties used in organic farming were better in forming symbiosis than the old, but the mycorrhizal effect on plant yield is seen only for old varieties. Demonstrating a variety effect on the development and 6 expression of symbiosis. The benefits of mycorrhizal symbiosis are more pronounced for the qualitative phenomena as the seed viability. The addition of a commercial inoculum in a similar greenhouse experiment modified these observations. This inoculum helped to improve wheat development but also the seed quality of some varieties, demonstrating both the importance of the plant genome in the beneficial expression of the symbiosis and the impossibility of indigenous mycorrhizal fungi to ensure optimal development of symbiosis. The previously observed field varietal effect was confirmed even after adding an exogenous inoculum as, excepted for one variety, inoculation has improved yield. This was especially noticeable in the variety that was most productive, stressing the importance to develop crossing strategies to increase the wheat response to mycorrhiza.

Dans un contexte d'usage raisonné des antibiotiques lié au développement des résistances bactériennes, il est pertinent de chercher à optimiser les profils d'exposition plasmatique qui conduiraient à la meilleure efficacité de l'antibiotique sur les bactéries pathogènes. La charge bactérienne n'est pas stationnaire tout au long du développement d'une infection, mais elle augmente spontanément ou diminue avec un traitement antibactérien efficace. L'objectif de cette thèse était d'évaluer l'influence de la variation de la charge bactérienne sur l'efficacité des antibiotiques et du système immunitaire.Au cours d'un premier travail, nous avons montré que dans les conditions de réalisation de tests de sensibilité in vitro (détermination de CMI), une dégradation de certains antibiotiques se produisait, d'amplitude variable selon les molécules testées. Cette dégradation peut être responsable d'une augmentation des valeurs de CMI et de CMB. Les variations observées étaient cependant inférieures à une dilution au demi dans une gamme de concentrations. Cette dégradation ne devrait pas avoir d'impact significatif sur les résultats des tests de sensibilité aux antibiotiques concernés, excepté dans des cas particuliers comme des pathogènes à croissance très lente. Dans un deuxième travail, nous avons étudié in vitro chez E. coli et S. aureus l'effet de la taille de l'inoculum bactérien sur l'activité bactéricide de 2 céphalosporines, la céphalexine et le cefprozil. Nous avons observé une diminution de l'activité bactéricide des 2 céphalosporines avec l'augmentation de la taille de l'inoculum chez E. coli et S. aureus. Nous avons également montré une efficacité et une puissance moins importante des 2 céphalosporines sur S. aureus par rapport à E coli.Dans un troisième temps, nous avons développé un système incluant les trois composantes suivantes : une bactérie - S. aureus -, des cellules du système immunitaire - des macrophages murins issus de la moelle osseuse - et un antibiotique -la céphalexine-. Dans ce système, nous avons fait varier la taille de l'inoculum bactérien de départ ainsi les concentrations en antibiotique. Une augmentation de la phagocytose bactérienne et de la mortalité des macrophages ont été observées avec l'augmentation de la charge bactérienne. L'activité bactéricide des macrophages était saturable et en présence d'une charge bactérienne trop importante, une partie des macrophages sont devenus un réservoir de S. aureus phagocytés. En présence de la céphalexine, qui a une distribution exclusivement extracellulaire, les quantités de bactéries extracellulaires, " candidates " à la phagocytose, ont diminué. Ainsi, en présence de céphalexine et pour les charges bactériennes initiales les plus faibles, les capacités de survie et de bactéricidie des macrophages ont été préservées. Cette action n'a cependant plus été visible en présence de gros inocula bactériens pour lesquels l'action limitée de la céphalexine n'a pas permis de prévenir la saturation des macrophages et ses conséquences. Le modèle à trois composantes que nous avons développé constitue une première étape dans le développement de modèles in vitro qui associent des éléments de l'immunité innée aux modèles pharmacologiques classiques bactéries/antibiotiques, avec l'objectif d'optimiser l'évaluation préclinique de molécules antibactériennes. / As one of the current pre-eminent public health concerns is to reasonably use antibiotics in order to limit antibacterial resistance development, it appears relevant to determine the plasmatic exposition profile that would lead to the best efficiency of the antibiotic on pathogenic bacteria. The bacterial load is not stationary during an infection but it increases or decreases with an effective antibiotic treatment. The aim of this thesis was to evaluate the influence of variation of the bacterial load on antibiotic and immune system activity.First, we showed that during antibacterial sensibility tests, such as standard MIC determination, some antibiotics underwent abiotic degradation during incubation, with a magnitude depending on the drug tested. This degradation can increase MIC and MBC values. However, the observed discrepancy (less than one twofold dilution) suggests that this would only be clinically significant in special cases such as slow-growing bacteria.Then, we studied, with E. coli and S. aureus, the in vitro effect of the bacterial inoculum size on bactericidal activity of 2 cephalosporins, cephalexin and cefprozil. We observed a decrease of bactericidal activity of both cephalosporins with an increase of the initial inocula of E. coli and S. aureus. A decreased efficacy and potency of the 2 cephalosporins against S. aureus compared to E. coli was also found. Finally, we developed an in vitro 3-components model including a bacterium -S. aureus-, cells of the immune system -murine bone-marrow-derived macrophages- and an antibiotic -cephalexin-. Within this system, we tested several initial bacterial inoculum sizes and different antibiotic concentrations. Increased bacterial phagocytosis and macrophage mortality were observed with increasing bacterial inocula. Bactericidal activity of macrophages was saturable and faced to a large bacterial inoculum, some macrophages became a reservoir for living S. aureus. With cephalexin, which is an extracellular antibiotic, extracellular bacteria diminished over time implying a diminution of the bacteria to be phagocytosed by macrophages. Thus, macrophages bactericidal and survival abilities were preserved with cephalexin and small bacterial inocula. This effect of the antibiotic was no longer visible with highest bacterial inocula for which limited action of cephalexin did not allow to prevent macrophages bursting. The tripartite model we developed is a first step toward innovative in vitro models combining elements of innate immunity with classical bacteria/antibiotics pharmacological models, with the objective of optimising preclinical evaluation of antibacterial drugs.

Las enfermedades de la madera se encuentran entre las patologías más dañinas que afectan al cultivo de la vid. El pie negro es una de las más destacadas, afectando a las plantas en vivero y en plantaciones jóvenes. Los agentes causales están incluidos dentro de los géneros Campylocarpon, ¿Cylindrocarpon¿, Cylindrocladiella e Ilyonectria. Éstos se caracterizan por ser habitantes del suelo y, se ha demostrado que permanecen en él, infectando al material de propagación cultivado en campos de vivero. La presencia de hongos asociados al pie negro en vivero, así como sus fuentes potenciales de inóculo en suelos de vivero y de viñedos comerciales, no han sido nunca estudiados en España. En este sentido, el objetivo de esta Tesis ha sido estudiar la epidemiología de hongos que causan el pie negro de la vid en España. En primer lugar, las distintas fases del proceso viverístico se evaluaron como fuentes potenciales de inóculo de estos patógenos. Se tomaron muestras en cuatro fases del proceso de propagación de las que se extrajo el ADN, detectándose las especies causantes del pie negro de la vid mediante multiplex, nested PCR. En las fases estudiadas se detectaron I. liriodendri y el complejo I. macrodidyma. También se estudió la detección de especies de Ilyonectria en material de propagación de vid, antes y después de la fase de enraizamiento en campos de vivero, mediante técnicas de aislamiento y multiplex, nested PCR. Este estudio confirmó que el número de plantas infectadas con estos patógenos aumenta durante el proceso de enraizamiento en campos de vivero. Ilyonectria torresensis fue la única especie aislada de las plantas tras la inducción del callo. Sin embargo, las especies I. liriodendri, I. novozelandica e I. torresensis se aislaron frecuentemente tras el período de cultivo en campos de vivero. Respecto a la detección molecular, se detectaron un número elevado de muestras positivas en planta tras la inducción del callo y después del proceso de enraizamiento. Mediante el uso de cuatro técnicas diferentes, aislamiento fúngico a partir de raíces de plántulas de vid utilizadas como plantas trampa, aislamiento a partir de raíces de malas hierbas, multiplex, nested PCR y qPCR, se estudió el suelo de campos de plantas madre como fuente de inóculo de estos patógenos. De las raíces de plantas trampa se aislaron las especies I. alcacerensis, I. macrodidyma, I. novozelandica e I. torresensis. ¿Cylindrocarpon¿ macrodidymum fue la única especie aislada de las raíces de malas hierbas. En los análisis de suelos realizados mediante multiplex, nested PCR así como mediante qPCR se observó un elevado porcentaje de detección del complejo I. macrodidyma en muestras de ADN de suelo, mientras que el porcentaje de detección de I. liriodendri fue menor. Las mismas técnicas descritas para campos de plantas madre se utilizaron para estudiar los suelos de campos de vivero y de viñedos comerciales. Los resultados obtenidos en estos dos tipos de campos fueron similares a los obtenidos en campos de plantas madre. Finalmente, se estudió el efecto de la temperatura, pH y potencial osmótico (¿s) sobre el crecimiento miceliar, la esporulación y la producción de clamidosporas de ¿C.¿ liriodendri, ¿C.¿ macrodidymum y ¿C.¿ pauciseptatum, con el objetivo de mejorar el conocimiento de los factores que afectan al crecimiento, reproducción y supervivencia de estos patógenos. Todos los aislados estudiados crecieron en un rango de temperaturas comprendido entre 5 y 30ºC. Se observó crecimiento miceliar en un rango de pH comprendido entre 4 y 8. Respecto al efecto del ¿s, el crecimiento miceliar fue mejor en medio de cultivo PDA ajustado a -0,5, -1,0 y/o -2,0 MPa en comparación con el crecimiento miceliar observado en PDA sin ajustar a ningún ¿s (-0,3 MPA). La mayoría de los aislados de ¿Cylindrocarpon¿ esporularon a todas las temperaturas, pHs y valores de ¿s estudiados. En general, la producción de clamidosporas no se vio afectada por la temperatura, el pH y el ¿s. / Agustí Brisach, C. (2013). Studies on the epidemiology of black-foot disease of grapevine in Spain [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/27598

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) constitui um complexo de espécies de mosca-brancas que são pragas em várias culturas de importância econômica, especialmente pelo alto potencial biótico e capacidade de transmitir vírus de plantas, como Tomato chlorosis virus (ToCV). A transmissão de vírus por insetos vetores é um processo biológico complexo, pois depende de múltiplas interações envolvendo o patógeno, vetor e plantas hospedeiras. Vírus de plantas podem afetar direta ou indiretamente o comportamento do inseto vetor a fim de favorecer sua disseminação. Postula-se que o efeito da infecção viral na seleção de plantas hospedeiras por moscas-branca pode variar com a expressão de sintomas e com a espécie vegetal, podendo favorecer a aceitação de algumas espécies de plantas para alimentação e colonização, aumentando a sua importância na epidemiologia. Neste trabalho foram investigados os efeitos de ToCV na preferência da espécie Middle East Asia Minor 1 (MEAM1; anteriormente conhecida como biótipo B) de B. tabaci por diferentes espécies vegetais. Utilizaram-se adultos da mosca-branca que previamente adquiriram ToCV em folhas de tomate infectadas (virulíferos) e adultos não expostos ao vírus (avirulíferos). Os experimentos consistiram em analisar a preferência para pouso e oviposição dos insetos virulíferos e avirulíferos em diferentes partes de plantas sadias e infectadas de tomate (ápice, terço médio e baixeiro); entre tomateiros infectados com ou sem sintomas da virose; e entre espécies vegetais, infectadas ou não, sendo duas de vegetação espontânea, Physalis angulata L. (joá-de-capote) e Solanum americanum L. (maria-pretinha) e uma cultivada, Solanum lycopersicum L., o tomateiro. Além disso, avaliou-se a eficiência de transmissão de ToCV para plantas de tomate utilizando-se tais espécies vegetais como fontes de inóculo. Observou-se que os insetos preferem predominantemente a parte apical das plantas tanto para pouso quanto para oviposição. A concentração de ToCV é maior no terço médio de plantas de tomate, seguido pelos terços apical e basal, embora a eficiência de transmissão por B. tabaci MEAM1 seja semelhante quando o inseto adquire o vírus em folhas de diferentes partes da planta. Adultos avirulíferos preferem pousar e colocar mais ovos em folhas de tomateiro assintomáticas (em fase latente da infecção por ToCV) do que em folhas sintomáticas, evidenciando a importância de infecções latentes na disseminação do vírus, enquanto que adultos virulíferos não discriminam entre folhas com ou sem sintomas. Insetos virulíferos preferem, em ordem decrescente, pousar em S. americanum (maria-pretinha), tomateiro e P. angulata, independentemente de estarem ou não infectadas por ToCV. Já insetos avirulíferos preferem tomateiro em relação à maria-pretinha no caso de plantas sadias, mas não exibem diferenças em preferência entre as duas espécies quando infectadas pelo vírus. A eficiência de transmissão de ToCV para tomateiro foi semelhante após a aquisição em maria-pretinha, tomateiro e P. angulata; ou seja, as três espécies podem servir como fontes de inóculo para a disseminação do vírus, com destaque para maria-pretinha, por ser uma planta preferida para pouso e oviposição por B. tabaci MEAM1. / Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a complex of whitefly species that are pests in several crops of economic importance, especially for its high biotic potential and ability to transmit plant viruses, such as Tomato chlorosis virus (ToCV). Virus transmission by insect vectors is a complex biological process because it depends on multiple interactions between the pathogen, vector and host plants. Plant viruses can directly or indirectly affect the behavior of the insect vector in order to optimize its spread. It is postulated that the effect of the viral infection on host plant selection by whiteflies may vary with plant species and age of infection, which may favor the acceptance of particular host plants for feeding and colonization, increasing their importance in epidemiology. This work was aimed at investigating the effects of ToCV on the preference of B. tabaci Middle East Asia Minor 1 (MEAM1; formerly known as B biotype) for different host plants. Whitefly adults that previously acquired ToCV from infected tomato leaves (viruliferous) and adults not exposed to the virus (non-viruliferous) were used in the choice assays. The experiments consisted of analyzing the preference for settling and oviposition of B. tabaci MEAM1 on different parts of healthy and infected tomato plants (apical, middle and lower portions); among infected tomato plants with or without virus symptoms (time of viral infection); and among different host plants, including two weeds Physalis angulata L. (joá-de-capote) and Solanum americanum L. (maria-pretinha) and one crop plant, Solanum lycopersicum L. (tomato). In addition, we investigated whether there is a difference in the efficiency of transmission of ToCV to tomato plants using such plant species as sources. It was found that the whiteflies prefer the apical part of tomato plants for both landing and oviposition. ToCV concentration is higher in the middle third of tomato plants, followed by the apical and basal thirds, but transmission efficiency by B. tabaci MEAM1 is similar when the insect acquires the virus from leaves of different parts of the plant. Non-viruliferous adults prefer to settle and lay eggs on asymptomatic (in latent phase of ToCV infection) than on symptomatic leaves, indicating the importance of latent infections on virus spread, whereas virulferous adults do not discriminate between leaves showing symptoms or not. Viruliferous insects prefer to settle (in decreasing order) on S. americanum, tomato and P. angulata, regardless of the plant infection or not by ToCV, whereas non-viruliferous insects prefer tomato to S. americanum in the case of healthy plants, but do not discriminate between the two plant species when they are infected. Transmission efficiency of ToCV to tomato plants was similar after acquisition on S. americanum, tomato and P. angulata, showing that the three species may serve as inoculum sources for virus spread; S. americanum appears to be particularly important, since it is a preferred host for settling and oviposition by B. tabaci MEAM1.

Com o objetivo de estudar o uso de inóculo de fezes em substituição do conteúdo ruminal de bubalinos na técnica in vitro de produção de gases, este presente trabalho comparou as avaliações realizadas em três ensaios. Foram utilizados três bubalinos da raça Mediterrâneo, machos, adultos, castrados, fistulados no rúmen com média de peso vivo de 450 (± 18,7) kg. Estes animais receberam uma dieta basal, composta de silagem de milho (70%) e concentrado (30%). Estes animais foram os doadores dos 2 tipos de inóculos, que foram conteúdo ruminal (CR) e fezes. O primeiro ensaio realizado foi com alimentos concentrados: grão de milho, farelo de soja, farelo de trigo e farelo de algodão; o segundo ensaio foi com leguminosas forrageiras: alfafa (Medicago sativa L. ), estilosantes pioneiro (Stylosanthes macrocephala cv. Pioneiro), soja perene (Neonotonia wightii) e leucena (Leucaena leucocephala); e o terceiro e último ensaio foi realizado com gramíneas forrageiras: capim braquiarão (Brachiaria brizantha cv. Marandu), capim buffel (Cenchrus ciliaris L. cv. Biloela), estrela africana (Cynodon plectostachyus) e capim mombaça (Panicum maximum Jacq. cv. Mombaça). Os valores médios obtidos de produção potencial de gases em cada ensaio foram menores (P<0,05) para as amostras fermentadas com inóculos de fezes que com conteúdo ruminal, sendo respectivamente, para concentrados (140,23 e 194,08 mL.g-1MS), gramíneas (161,99 e 230,25 mL.g-1MS) e leguminosas (141,78 e 170,70 mL.gm-1MS). Conclui-se que inóculos de fezes não apresentam condições satisfatórias para substituição do inóculum com conteúdo ruminal para uso na técnica de produção in vitro de gases. / In order to study the use of faeces as inoculum as alternative for buffalo rumen contents in the in vitro gas production technique, the present work evaluations of three tests. We used three Mediterranean buffalos, male, adult, neutered, fistulated in the rumen, with an average live weight of 450 (± 18.7) kg. These animals received a basal diet composed of corn silage (70%) and concentrated (30%). These buffalo were the donors of the two types of inocula, rumen content (CR) and faeces. The first test was carried out with concentrate foods: corn grain, soybean meal, wheat bran and cottonseed meal, the second test was with legumes: alfalfa (Medicago sativa L. ), Pioneiro estilo (Stylosanthes macrocephala cv. Pioneiro) , perennial soybean (Neonotonia wightii) and leucaena (Leucaena leucocephala) and the third and last test was carried out with grasses: Marandu grass (Brachiaria brizantha cv. Marandu), buffel grass (Cenchrus ciliaris L. cv. Biloela), African Star grass (Cynodon plectostachyus) and Mombasa grass (Panicum maximum Jacq. cv. Mombasa). The average values of potential production of gas in each test were lower (P<0.05) for samples fermented with an inoculum of faeces with rumen contents, being respectively, for concentrates (140.23 and 194.08 mL.g-1MS), grasses (161.99 and 230.25 mL.g-1MS) and legumes (141.78 and 170.70 mL.g-1MS). It follows that fecal inoculum unsatisfactory condition for replacing the inoculum with rumen technique for use in the in vitro production of gases technique.

Ectomycorrhizas generally improve seedling mineral nutrition and growth, so I hypothesized that decline of the Florida native pine variety Pinus elliottii var. densa Little & Dorman is related to deficiency of appropriate ectomycorrhizal (ECM) fungi in the pine's native flatwoods. At Archbold Biological Station I examined how quickly ECM fungi colonize P. elliottii var. densa seedlings and I compared the effect of local absence versus presence of adult pines on ECM colonization and pine seedling performance. Under controlled greenhouse conditions, I investigated how a wide range of ECM colonization and spread of extraradical mycelium throughout a large volume of relatively infertile, flatwoods soil enhance the mineral nutrition and growth of pine seedlings. In a field bioassay, I transplanted two-month-old pine seedlings to three flatwoods sites with low (4 pines/400 square m), medium (9 pines/400 square m), and high (19 pines/400 square m) adult pine densities. I subsequently excavated seedlings every two weeks for four-and-a-half months and determined their ECM colonization, response to shade, and response to surrounding grass density. Across all sites, pine seedlings in high shade had a higher mean chlorophyll concentration and lower stem dry weight than in full sun. Competition with grass reduced seedling survival and stem dry weight. Initial colonization was rapid and not different among sites, with 5.4 % of roots colonized 15 days after transplant. Pine seedlings had midpoint means of 29.5 %, 18.1 % and 21.3 % ECM root tips in low, medium and high adult pine density sites, respectively, suggesting that pine seedlings establishing in flatwoods encounter sufficient ECM fungi to support their growth, regardless of adult pine density. In a field experiment, I determined in the presence versus absence of adult pines if pine seedlings had higher ECM colonization and consequent improved survival, mineral nutrition, and growth. Within and beyond pine stands, I transplanted seedlings into intact or drilled, hyphae in-growth pipes buried in the ground. I placed autoclaved or fresh ECM root inoculum in two sets of intact pipes, and autoclaved inoculum in drilled pipes into which mycorrhizal hyphae could extend from the surrounding vegetation. Seven-and-a-half months after transplant, ECM hyphae had penetrated the drilled pipes and colonized pine seedlings, but roots from the surrounding vegetation also penetrated pipes. Extraneous roots reduced the survival of seedlings both within and beyond pine stands, but extraneous roots reduced seedling growth only beyond pine stands. Because percentage ECM root tips was higher in the presence (53 %) than in the absence (38.8%) of adult pines, pine stands might benefit the competitive ability of seedlings by increased ECM colonization and possibly by common mycorrhizal networks connecting seedlings to adults. Because beneficial effects of ECM in the field were small, I also examined ECM effects on pine seedlings in a greenhouse experiment. I manipulated ECM fungus colonization and the volume of flatwoods soil to which extraradical mycelium had access. In a small volume of soil (220 mL), fresh ECM root inoculum promoted the mycorrhizal colonization of seedlings versus those receiving autoclaved roots, but seedling growth and uptake of Mg, Ca, and Zn was lower with fresh than with autoclaved root inoculum. Growth and mineral nutrient uptake likely was enhanced by a pulse of nutrients from autoclaved roots, but for inoculated plants may have been reduced because of nutrient retention by saprotrophic microorganisms degrading fresh ECM roots and because of mineral nutrient retention by ECM fungi. Ectomycorrhizal seedlings with extraradical mycelium access to a large soil volume had higher mean chlorophyll concentration than those in a small soil volume. Weekly disturbance of the extraradical mycelium, however, reduced foliar contents of Mn, K, P, N, and Zn by one-third to one-half, and reduced needle dry weight of seedlings by one-third, demonstrating the importance of extraradical mycelium accessing a large volume of soil when it is nutrient-poor. My research demonstrates that ECM fungi are widespread in flatwoods and rapidly colonize pine seedlings. ECM fungus inocula are greater in the presence than in the absence of adult pines, and ECM or seedlings' connections to a common mycorrhizal network improve seedlings' belowground competitive ability. ECM especially enhance seedling mineral nutrition and growth when undisturbed, extraradical mycelium extends throughout a large volume of soil. Populations of Pinus elliottii var. densa might best regenerate in flatwoods if seedlings recruit near adult pines and where there is little competition for light, water, and mineral nutrients.

The bacteria Streptomyces venezuelae produce the novel antibiotic jadomycin. The study of growth characteristics and metabolic behavior of the bacteria are necessary to scale up antibiotic production and facilitate further research. In this study, a method for producing consistent inoculum was developed that showed good repeatability when used in growth trials. The rod shaped spores of Streptomyces venezuelae were determined to be approximately 0.8 x 0.2 ?m with a smooth surface type. The effects of temperature and pH on bacterial growth and substrate consumption were examined in a 7 L bioreactor. Of the range of parameters tested (28, 32, 36 °C, and media pH of 5, 7 and 9), 32 °C with a media pH of 7 yielded the highest rate of growth (µmax of 1.43 hours-1 with a lag time of 7.7 hours). The results of all trials showed that free glucose was consumed before the maltose, which was the major sugar substrate in the media. The initiation of exponential bacterial growth occurred after rapid consumption of free glucose. A heat balance analysis was also performed over the bioreactor to identify the heat generated through agitation, losses over the vessel and the heat of metabolism from Streptomyces venezuelae. Under normal operating parameters 33 - 24 % of the heat generated through mixing was lost with the exhaust gas, while 56 - 64 % was lost through the bioreactor wall. The heat of mixing was calculated to be 1.62 J•s-1 while the maximum amount of heat generated by Streptomyces venezuelae metabolism and activity during a growth trial was 2.28 J•s-1 for 60 x 109 CFU?mL-1.