https://repositorio.ufu.br/handle/123456789/5161 Mon, 12 Oct 2026 15:52:21 GMT 2026-10-12T15:52:21Z https://repositorio.ufu.br:443/retrieve/0167e99a-9fc2-4c94-b630-392b56eb2937/ICIAG-removebg-preview.png https://repositorio.ufu.br/handle/123456789/5161 https://repositorio.ufu.br/handle/123456789/50581 Title: Avaliação da toxicidade de arsênio e cromo em microrganismos utilizados como bioinsumos na agricultura Abstract: Soil contamination by metals and metalloids represents an important stress factor for microorganisms of agricultural interest, potentially compromising their survival and establishment in agricultural systems. In this context, the present study aimed to evaluate the toxic effects of arsenic, in two distinct chemical forms, on the growth and cell viability of microorganisms used as bioinputs, as well as to compare these effects with those caused by chromium. The microorganisms Azospirillum brasilense Abv06, Bacillus aryabhattai CMAA 1363, Bradyrhizobium japonicum SEMIA 5079, and Saccharomyces cerevisiae were evaluated under different concentrations of arsenite, arsenate, and hexavalent chromium in in vitro assays. Microbial growth was assessed by measuring optical density at 600 nm (OD₆₀₀), while cell viability was determined by colony-forming unit (CFU) counts. Growth data were fitted using nonlinear regression with the four-parameter log-logistic model (LL.4), which allowed the characterization of different response levels of the microorganisms to the tested concentrations. The results demonstrated that toxicity varied according to the chemical form of the contaminant, its concentration, exposure time, and the characteristics of each microorganism. Arsenate showed low toxicity to most of the microorganisms evaluated, whereas arsenite caused a greater reduction in growth and, under certain conditions, high cell mortality, with B. japonicum showing particularly high sensitivity. The other microorganisms exhibited variable responses to arsenite depending on concentration and exposure time. Chromium, in turn, exhibited more severe toxicity, causing strong growth inhibition and high mortality in some of the microorganisms evaluated. The combined analysis of optical density and CFU counts demonstrated that reduced growth was not always associated with an immediate loss of cell viability, indicating the occurrence of sublethal responses during exposure to the contaminants. Therefore, the results demonstrate that the response of microorganisms of agricultural interest to arsenic and chromium depends on the chemical form of the contaminant and the biological characteristics of each organism. These findings highlight the importance of considering both growth and cell viability when assessing microbial tolerance under contamination conditions. Sat, 23 May 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50581 2026-05-23T00:00:00Z https://repositorio.ufu.br/handle/123456789/50504 Title: Potencial de Bipolaris crotonis como agente de controle biológico do capim-pé-de-galinha (Eleusine indica) Abstract: Goosegrass (Eleusine indica) is a widely distributed weed in agricultural and forest production systems, characterized by high competitive ability and increasing reports of resistance to chemical herbicides. This scenario has intensified the search for alternative control methods, especially biological control strategies. The present study aimed to evaluate the potential of the fungus Bipolaris crotonis as a biological control agent against E. indica. The fungal isolate was obtained from seeds of the target weed showing disease symptoms, collected in the municipality of Monte Carmelo, Minas Gerais, Brazil. Morphological and molecular analyses were performed to confirm the identity of the isolate. Pathogenicity was assessed through inoculation of mycelial discs onto healthy plants, fulfilling Koch’s postulates. Subsequently, the biocontrol potential of the fungus was evaluated through the application of a conidial suspension produced in a biphasic medium, at a concentration of approximately 1 × 10⁶ conidia mL⁻¹. Inoculated plants showed progressive development of necrotic leaf lesions, ultimately leading to plant death. At the end of the evaluation period, an average control rate of approximately 83% was observed, classified as “good” according to the scale proposed by the Brazilian Society of Weed Science. Additionally, this study represents the first record of Bipolaris crotonis associated with Eleusine indica in Brazil, expanding current knowledge on the geographic distribution of this pathogen. The results indicate that B. crotonis shows promising potential as a bioherbicide and may be incorporated into integrated weed management strategies, contributing to the reduction of reliance on chemical herbicides in agricultural and forest systems. Thu, 05 Mar 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50504 2026-03-05T00:00:00Z https://repositorio.ufu.br/handle/123456789/50502 Title: Morphoagronomic characterization and image-based herbivory analysis for pest resistance in dwarf tomato using artificial neural networks Abstract: Dwarf tomato plants with optimized combining ability offer distinct advantages for hybrid development, including superior agronomic performance, fruit quality, and pest resistance. However, Santa Cruz-type dwarf tomato germplasm remains undercharacterized. This study evaluated morphological traits on seven populations of Santa Cruz-type dwarf tomatoes, the donor parent UFU MC TOM 1, the recurrent parent UFU-TOM-MOTHER-2, and the control cultivar Caniati. Additionally, the wild accession Solanum pennellii was included to quantify acylsugar content. Pest resistance was evaluated through acylsugar quantification and analyses of herbivory caused by Tuta absoluta and Liriomyza huidobrensis. Populations UFU-Sci#6.12-2.1.5, UFU-Sci#6.12-2.1.7, and UFU-Sc#8.3.2-2.1.2 emerged as superior, exhibiting elevated acylsugar levels, reduced pest damage, and improved fruit quality. Importantly, acylsugar content was strongly associated with increased pest resistance, particularly against T. absoluta and L. huidobrensis, mimicking the defensive profile of the wild S. pennellii accession. These findings support the development of pest-resilient, productive tomato cultivars aligned with sustainable agriculture goals. Tue, 08 Apr 2025 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50502 2025-04-08T00:00:00Z https://repositorio.ufu.br/handle/123456789/50491 Title: Monitoramento da qualidade da água dos bebedouros do Campus Glória da Universidade Federal de Uberlândia Abstract: According to the Law nº. 9,433/1997, which established the National Water Resources Policy and the National Water Resources Management System, the present and future generations should have access to potable water, however, this is not a reality for all Brazilians, since nearly 35 million people in Brazil live without treated water. Despite being vital for human existence, water can carry substances and microorganisms harmful to health. Therefore, monitoring water quality based on potability parameters, such as physicochemical and microbiological analyses, is essential. Thus, in this project, the water quality of drinking fountains in the three buildings of the Glória campus of the Federal University of Uberlândia (Uberlândia, Minas Gerais) was analyzed in accordance with the standards established by the Ordinance of Health Ministry nº 888/2021. The water quality was investigated through analysis using the multiple-tube technique and physicochemical parameters such as pH, turbidity, conductivity, dissolved solids and chlorine residual concentration. The analyses were performed in triplicate at 17 drinking fountains over a 12-month period, with four sampling events at each drinking fountain, totaling 68 samples. In the bacteriological analyses, no coliforms were detected in any sample, indicating the potability of the consumed water and the absence of contamination. For the chlorine residual parameter, the reference value for drinking water is 0,2 to 5 mg.L-1; however, in nine months the samples showed slightly lower values, occurring in months 1, 4, and 7 in block 1CCG; months 2 and 8 in block 1BCG; and in all analyzed months in block 1DCG. The mean values of this parameter was 0.19 mg.L-1. The other physicochemical parameters were in accordance with the Potability Standard for water for human consumption, with mean values of: pH 7.3, turbidity 0.38 NTU, conductivity 88.1 µS.cm-1, and dissolved solids 43.5 mg.L-1, demonstrating the good quality of the water on this campus. The data obtained showed that the samples were in compliance with the legislation, indicating the potability of the analyzed water. However, the chlorine residual parameter presented some values slightly below the recommended range, possibly due to the analyses being performed on water after passing through the filtration system, which may partially remove chlorine. Therefore, continuous monitoring of this parameter is essential to ensure the maintenance of water quality. Notes: 99 Wed, 25 Mar 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50491 2026-03-25T00:00:00Z