There is a need in the cotton industry for cultivars with enhanced lint yield potential and high-quality fiber properties. Indole-3-acetic acid (IAA) is a phytohormone that is predominantly responsible for cell elongation and required for primary elongation in cotton fiber development. An increase in IAA at specific fiber developmental stages may promote increased lint percent and longer fibers. Objectives of this research project were to determine how exogenous applications in a field environment affect fiber traits and lint yield potential in diverse genotypes. The first study examined application methods to ascertain the optimal placement and timing of IAA. The second study focused on genotype reactions to elevated levels of IAA. Results indicate exogenously applied IAA provided a potential yield increase but did not improve fiber length. Further research needs to be conducted to effectively understand IAA’s role in fiber development and establishing protocols for maximizing IAA potential in a field environment.

The purpose of this study was to determine the endogenous levels of indole-3-acetic acid throughout the life cycle of Chlorella pyrenoidosa, and to show a correlation between onset of cell division and IAA levels.

It was the purpose of this study to investigate the effect of various concentrations of IAA on the nucleic acids of Chlorella pyrenoidosa TX 7-11-05. The time during the life cycle when the greatest effect occurred was investigated by the use of synchronous cultures.

Fungal infections are caused by a variety of fungi, and with a variety of clinical manifestations. Antifungal treatments are limited due to host toxicity and fungi gaining resistance. By utilizing the model organism Saccharomyces cerevisiae, we hope to elucidate the molecular mechanisms of fungal pathogenesis that we can then validate in the human pathogen Candida albicans, as well as explore options for novel therapies. Small molecule signaling is a method by which single-cell organisms can communicate with one another, enabling them to coordinate gene expression. This is a useful tool because it allows microbes to turn on phenotypes that are only valuable when done in large numbers, such as bioluminescence, or virulence traits. We have previously shown that the yeast Saccharomyces cerevisiae synthesizes the secondary metabolite indole-3-acetic acid (IAA) from tryptophan. IAA is secreted into the environment, where it acts as a signal. At low concentrations, the IAA signals yeast to induce virulence traits, while at high concentrations, it is lethal. The purpose of this thesis was to investigate the molecular mechanism of IAA (plant hormone auxin) regulation in fungi, specifically, Saccharomyces cerevisiae and the human pathogen Candida albicans. Towards this end, I first focused my efforts on evaluating the role of S. cerevisiae Grr1, as a putative IAA receptor. By evaluating the IAA response of several Grr1 mutants, I was able to show that the leucine-rich repeat region, while not required for function, likely plays a significant role in maintaining the structural integrity of the protein. Next, I evaluated IAA associated phenotypes, such as filamentation, surface adhesion and IAA uptake of the grr1 null mutant in the human pathogen Candida albicans. Together, these data support the hypothesis that GRR1 regulates IAA response, probably by regulating the IAA uptake carriers.

The effects of polyamines, indole-3-acetic acid ( IAA ) and gibberellic acid ( GA3 ) on root elongation in radish ( Raphanus sativus L. cv. Luh Chin ) were studied. Incubation of radish seedlings in spermine or spermidine at 0.01 mM for 1hour, and then transferred to deionized water for 24 hours at 25¢J in the dark promoted root elongation as compared with concentration at 0.1 or 2 mM. When roots were treated with spermine or spermidine at 1 mM for 5 minutes, and then transferred to deionized water for 24 hours, root length increased significantly compared with controls. However, root length reduced gradually with increasing treatment times. Putrescine did not affect root elongation when treated in the same manner as spermine or spermidine. Exogenous spermidine synthesis inhibitor ( cyclohexylamine ) at 0.01, 0.1, 1 or 2 mM to the roots inhibited root elongation. The inhibition of root elongation was parallel to cyclohexylamine doses. Root length increased when spermine at 1 mM plus IAA at 10¡Â¹ ¡Ñ 6 nM was applied for 1 hour, and then transferred to deionized water for 24 hours compared with spermine at 1 mM plus IAA 10¡Â² or 1¡Ñ 6 nM. Root length was longer when treated with spermidine at 1 mM plus IAA at 10¡Â²¡Ñ 6 nM than at 10¡Â¹ or 1¡Ñ 6 nM. Root treated with spermine at 1 mM plus GA3 at 10¡Â²¡Ñ3 £gM Resulted in a longer root than treated with spermine at 1 mM plus GA3 at 10¡Â¹ or 1¡Ñ 3 £gM. Roots treated with spermidine at 1 mM plus GA3 at 10¡Â²¡Ñ3 £gM promoted root elongation. However, any treatments of spermine or spermidine in combination with IAA or GA3 significantly reduced the root length when compared with controls. Furthermore, either IAA or GA3 could not restore the inhibitory effects of root elongation caused by spermine or spermidine treatment at 1 mM for 1 hour and then transferred to deionized water for 24 hours. Endogenous spermidine and spermine contents after exogenous spermine plus GA3 treatment increased by increasing GA3 concentrations. But endogenous spermidine and spermine contents was the least in spermine 1 mM plus IAA 10¡Â¹ ¡Ñ 6 nM treatment. However, endogenous spermidine contents after exogenous spermidine plus IAA or GA3 application reduced significantly when compared with controls. But there is no significant difference of spermidine content between different exogenous IAA doses. In contrast, spermidine content maintained at a high level in spermidine at 1 mM plus GA3 at 10¡Â²¡Ñ3 £gM as compared with other spermidine plus GA3 combinations. However, endogenous spermine contents were not affected by exogenous spermidine plus IAA or GA3.

Cu-treated peanut seedlings not only showed a significant inhibition in peanut root growth, but also a decrease in endogenous indole-3-acetic acid (IAA) contents . The decline of IAA content in Cu-treated tissues is accompanied by an increase in cationic peroxidase activity. In addition, the increase in cationic peroxidase (pI 8.5) activity is correlated with an increase in cationic peroxidase transcripts. Cu might suppress the growth of peanut roots by inducing the synthesis of the cationic peroxidase isozyme that degrades endogenous IAA, causing the retardation of peanut root growth. The increase in activity of anionic peroxidases (pI 3.5) is also correlated with the rise in lignin content in Cu-treated roots. We suggest that the increase in anionic peroxidases (pI 3.5) induced by Cu might be responsible for lignin synthesis in peanut roots, and remove excess hydrogen peroxide, thus serving a detoxifying role during Cu treatment.

Magister Scientiae - MSc (Biotechnology) / Endophytic bacteria are known to have an endosymbiotic relationship with plants and provide them with many beneficial properties. These bacteria stimulate plant hormones, provide protection from pathogens and increase nutrient availability in the environment. In this study some of these potential growth factors were tested. Endophytic bacteria have the potential to be of great value for the increase of crop production. They offer a variety of processes that aid in plant growth promotion in an ecofriendly manner. The use of endophytic bacteria provides a cheaper and cleaner approach compared to industrial made fertilizers. They also have potential uses in bioremediation to clean the environment polluted by industrial processes. Endophytes were isolated and showed significant growth improvement. Each isolate displayed different morphologies. Isolates were tested for classical growth promotion mechanisms such as the ability to solubilize phosphate, Indole-3-acetic acid and siderophore production. Inductively Coupled Plasma Optical Emission Spectrometry was performed to measure the effect of the isolates on the plants nutrient profile. The isolates were then tested again while the plants were under heavy metal stress to determine if they were still capable of growth promotion. The plants were then assayed for cell death using Evans blue and biomass was measured to determine the effect of vanadium stress. Inductively Coupled Plasma Optical Emission Spectrometry was performed again to assess the change in nutrient profile while under vanadium stress. / 2021-08-31

The nursery/greenhouse industry is innovative. There have been several reports in the popular literature of non-traditional adjuvants used in plant propagation; however, these claims have never been evaluated in a scientific setting. Five studies, conducted at the South Mississippi Branch Experiment Station in Poplarville in 2019 and 2021 determined the impact that adding honey to water-soluble auxin solutions and surfactants to foliar applied auxin solutions on physiological responses associated with adventitious root formation. Treatments in studies presented in chapters two and three included three honey sources (multiflora, local, and Manuka). Honey-infused water-soluble auxin solutions affected plant species but not in the measured physiological responses. Studies presented in chapters four and five examined the impact of water-soluble auxin solutions containing non-ionic surfactants on physiological responses compared to the industry standard basal quick-dip. Like our results for honey, adding surfactants to foliar-applied auxin solutions was species-specific. However, for difficult-to-root species, a foliar auxin application led to similar rooting compared to the current industry standard. For this reason, we recommend a foliar application for rooting Magnolia grandiflora ‘Southern Charm’. Finally, the study presented in chapter six examined the auxin application method, surfactant concentration, and seasonal impacts in rooting challenging to propagate species. The season that cuttings were taken had a significant impact on several of our tested responses. In addition, the auxin application method was also significant. To this end, we can recommend treating fall cuttings with a foliar auxin application for the best results.

Estudos têm mostrado a incidência de mastite bovina associada à alga Prototheca zopfii. O objetivo deste trabalho foi estudar a interação da P. zopfii com neutrófilos recuperados de leite bovino e avaliar o efeito do sistema ácido indol-3-acético/peroxidase de raiz forte (AIA/HRP) sobre a viabilidade deste microrganismo em experimentos in vitro. A P. zopfii foi recuperada de vacas com mastite clínica e, no laboratório, foram realizadas a caracterização molecular, morfológica e crescimento exponencial do microrganismo. Em seguida, neutrófilos recuperados de leite bovino foram incubados na ausência e na presença de P. zopfii opsonizada e foram avaliadas a produção de peróxido de hidrogênio, enzimas antioxidantes dos neutrófilos e microrganismo, e a capacidade fagocitária. Em outro estudo, a P. zopfii foi incubada com o sistema AIA/HRP e foram avaliadas a viabilidade por unidades formadoras de colônias (UFC), atividade de enzimas antioxidantes, integridade de membrana por exclusão com azul de Trypan e integridade do DNA. Os resultados foram analisados pela análise de variância com significância de 5% usando o teste Tukey. Foram observados diversos tamanhos celulares da P. zopfii, presença de autofluorescência, crescimento exponencial ao longo do tempo de incubação em que não foi possível determinar o início da fase de morte. Ainda, foram encontrados os genótipos 1, 2 e 3 nos isolados em estudo. A produção de peróxido de hidrogênio pelos neutrófilos na presença da alga foi estimulada 5 vezes em relação ao controle, estimulou a atividade das enzimas catalase (CAT) em 21% e glutationa redutase (GR) em 27% e não houve diferença significativa quanto à atividade de CAT, GR e superóxido dismutase (SOD) produzido pela P. zopfii. Também foi verificado que a P. zopfii não foi englobada pelo neutrófilo. O sistema AIA/HRP inibiu o crescimento do microrganismo em 45, 82 e 88% nos tempos de 4, 6 e 9 horas de incubação; a atividade da SOD, CAT, Glutationa Peroxidase (GPx) e GR aumentou respectivamente em 90, 120, 150% e 3,4 vezes; houve redução da viabilidade da P. zopfii em 10, 15, 20, 25 e 32% após os tempos de 4, 6, 8, 10 e 12 horas de incubação; e não afetou a integridade do DNA após 6 horas de incubação. Conclui-se que a P. zopfii é altamente resistente frente aos neutrófilos e demonstrou ser susceptível quanto ao efeito microbicida do sistema AIA/HRP. / Studies have shown the incidence of bovine mastitis associated with the algae Prototheca zopfii. The objective of this work was to study the interaction of P. zopfii with neutrophils recovered from bovine milk and to evaluate the effect of system indole-3-acetic acid/horseradish peroxidase (IAA/HRP) on the viability of this microorganism in vitro experiment. P. zopfii was recovered from cows with clinical mastitis and both the molecular and morphological characterization were performed besides the evaluation of exponential growth of the microorganism in the laboratory. Next, neutrophils recovered from bovine milk were incubated in the absence and presence of opsonized P. zopfii and were evaluated the production of hydrogen peroxide, antioxidant enzymes on neutrophils and microorganism, and phagocytic capacity. In another study, P. zopfii was incubated with the system IAA/HRP and the viability assessed by colony forming units (CFU), antioxidant enzymes activity, membrane integrity by exclusion with Trypan blue and DNA integrity. The results were analyzed by analysis of variance with a 5% significance using the Tukey test. Results from P. zopfii characterization showed various cellular sizes, presence of autofluorescence, exponential microorganism growth throughout the incubation time and was not possible to determine the beginning of the death. Moreover it was found genotypes 1, 2 and 3 in the isolates in study. The production of hydrogen peroxide by neutrophils in the presence of algae was stimulated 5 times compared to the control, increase the activity of catalase (CAT) in 21% and glutathione reductase (GR) in 27% was seen in neutrophils; and there was no significant difference in CAT, GR and superoxide dismutase (SOD) activity produced by P. zopfii. P. zopfii was not engulfment by neutrophils. The system IAA/HRP inhibited the growth of the microorganism in 45, 82 and 88% in the times of 4, 6 and 9 hours of incubation, the activity of SOD, CAT, glutathione peroxidase (GPx) and GR increased respectively by 90, 120, 150%, and 3.4 times, decreased the viability of P. zopfii 10, 15, 20, 25 and 32% after the times of 4, 6, 8, 10 and 12 hours of incubation, and did not affect the integrity of DNA after 6 hours of incubation. As a conclusion, P. zopfii is highly resistant to the neutrophils and demonstrated to be susceptible to the effect microbicidal of system IAA/HRP.

Estudos têm mostrado a incidência de mastite bovina associada à alga Prototheca zopfii. O objetivo deste trabalho foi estudar a interação da P. zopfii com neutrófilos recuperados de leite bovino e avaliar o efeito do sistema ácido indol-3-acético/peroxidase de raiz forte (AIA/HRP) sobre a viabilidade deste microrganismo em experimentos in vitro. A P. zopfii foi recuperada de vacas com mastite clínica e, no laboratório, foram realizadas a caracterização molecular, morfológica e crescimento exponencial do microrganismo. Em seguida, neutrófilos recuperados de leite bovino foram incubados na ausência e na presença de P. zopfii opsonizada e foram avaliadas a produção de peróxido de hidrogênio, enzimas antioxidantes dos neutrófilos e microrganismo, e a capacidade fagocitária. Em outro estudo, a P. zopfii foi incubada com o sistema AIA/HRP e foram avaliadas a viabilidade por unidades formadoras de colônias (UFC), atividade de enzimas antioxidantes, integridade de membrana por exclusão com azul de Trypan e integridade do DNA. Os resultados foram analisados pela análise de variância com significância de 5% usando o teste Tukey. Foram observados diversos tamanhos celulares da P. zopfii, presença de autofluorescência, crescimento exponencial ao longo do tempo de incubação em que não foi possível determinar o início da fase de morte. Ainda, foram encontrados os genótipos 1, 2 e 3 nos isolados em estudo. A produção de peróxido de hidrogênio pelos neutrófilos na presença da alga foi estimulada 5 vezes em relação ao controle, estimulou a atividade das enzimas catalase (CAT) em 21% e glutationa redutase (GR) em 27% e não houve diferença significativa quanto à atividade de CAT, GR e superóxido dismutase (SOD) produzido pela P. zopfii. Também foi verificado que a P. zopfii não foi englobada pelo neutrófilo. O sistema AIA/HRP inibiu o crescimento do microrganismo em 45, 82 e 88% nos tempos de 4, 6 e 9 horas de incubação; a atividade da SOD, CAT, Glutationa Peroxidase (GPx) e GR aumentou respectivamente em 90, 120, 150% e 3,4 vezes; houve redução da viabilidade da P. zopfii em 10, 15, 20, 25 e 32% após os tempos de 4, 6, 8, 10 e 12 horas de incubação; e não afetou a integridade do DNA após 6 horas de incubação. Conclui-se que a P. zopfii é altamente resistente frente aos neutrófilos e demonstrou ser susceptível quanto ao efeito microbicida do sistema AIA/HRP. / Studies have shown the incidence of bovine mastitis associated with the algae Prototheca zopfii. The objective of this work was to study the interaction of P. zopfii with neutrophils recovered from bovine milk and to evaluate the effect of system indole-3-acetic acid/horseradish peroxidase (IAA/HRP) on the viability of this microorganism in vitro experiment. P. zopfii was recovered from cows with clinical mastitis and both the molecular and morphological characterization were performed besides the evaluation of exponential growth of the microorganism in the laboratory. Next, neutrophils recovered from bovine milk were incubated in the absence and presence of opsonized P. zopfii and were evaluated the production of hydrogen peroxide, antioxidant enzymes on neutrophils and microorganism, and phagocytic capacity. In another study, P. zopfii was incubated with the system IAA/HRP and the viability assessed by colony forming units (CFU), antioxidant enzymes activity, membrane integrity by exclusion with Trypan blue and DNA integrity. The results were analyzed by analysis of variance with a 5% significance using the Tukey test. Results from P. zopfii characterization showed various cellular sizes, presence of autofluorescence, exponential microorganism growth throughout the incubation time and was not possible to determine the beginning of the death. Moreover it was found genotypes 1, 2 and 3 in the isolates in study. The production of hydrogen peroxide by neutrophils in the presence of algae was stimulated 5 times compared to the control, increase the activity of catalase (CAT) in 21% and glutathione reductase (GR) in 27% was seen in neutrophils; and there was no significant difference in CAT, GR and superoxide dismutase (SOD) activity produced by P. zopfii. P. zopfii was not engulfment by neutrophils. The system IAA/HRP inhibited the growth of the microorganism in 45, 82 and 88% in the times of 4, 6 and 9 hours of incubation, the activity of SOD, CAT, glutathione peroxidase (GPx) and GR increased respectively by 90, 120, 150%, and 3.4 times, decreased the viability of P. zopfii 10, 15, 20, 25 and 32% after the times of 4, 6, 8, 10 and 12 hours of incubation, and did not affect the integrity of DNA after 6 hours of incubation. As a conclusion, P. zopfii is highly resistant to the neutrophils and demonstrated to be susceptible to the effect microbicidal of system IAA/HRP.