Principais Coleções do Repositório
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dissertação
Diagnosis of bovine mastitis: performance of chromogenic medium compared to convencional methods and MALDI-TOF as gold standard technique
(Universidade Federal de Lavras, 2026-06-29) Duarte, Paula Oliveira; Dorneles, Elaine Maria Seles; Mian, Gláucia Frasnelli; Pereira, Carine Rodrigues; Cerqueira, Monica Maria Oliveira Pinho; Pereira, Carine Rodrigues; Minutti, Ana Flavia
Bovine mastitis is a highly prevalent, multifactorial inflammatory disease affecting the mammary gland of dairy cattle. Brazil has one of the most competitive dairy industries worldwide, and the economic impact of mastitis represents a major challenge for the dairy production chain. The disease negatively affects producers through reduced milk quality and animal welfare, milk discard, and increased expenditures on antimicrobial treatments. The microorganisms most commonly associated with bovine mastitis include Staphylococcus spp. (S. aureus and non-aureus Staphylococcus [NAS]), Streptococcus spp. (S. agalactiae, S. dysgalactiae, S. uberis, among others), coliforms (Escherichia coli, Klebsiella spp., and Enterobacter spp.), and Pseudomonas spp. Accurate identification of these pathogens is essential for guiding antimicrobial use on dairy farms. In the first chapter of this dissertation, we evaluated the diagnostic performance [diagnostic sensitivity (DSe), diagnostic specificity (DSp), and accuracy (Ac)] of a commercial chromogenic culture system (Mamitest, inLab, Brazil) compared with the conventional microbiological culture method recommended by the National Mastitis Council (NMC). Additionally, agreement (Cohen’s kappa coefficient) between two evaluators, one highly experienced in microbiology and one novice was assessed when interpreting the rapid test results. A total of 632 milk samples were analyzed using both diagnostic methods. The evaluation of Ac, DSe, DSp, and inter-observer agreement demonstrated a high level of agreement for most outcomes (Kappa > 0.80). Furthermore, DSe values were satisfactory for the main pathogen groups, particularly Gram-positive bacteria [0.86 (95% CI: 0.82–0.89)], staphylococci [0.88 (95% CI: 0.82–0.93)], and streptococci [0.93 (95% CI: 0.88–0.96)]. In the second chapter, we expanded upon the previous study by comparing both diagnostic methods with a reference standard consisting of bacterial culture and isolation followed by identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Diagnostic performance was assessed through the calculation of DSe, DSp, and Ac using milk samples cryopreserved at −80°C. In this phase, 526 bacterial isolates were recovered, of which 490 were successfully identified and classified into 61 different species. The chromogenic culture system demonstrated good performance as a screening tool for the major bacterial groups, particularly Gram-positive and Gram-negative organisms. Conventional microbiological culture showed superior performance in species-level differentiation; however, it exhibited only moderate DSe values for some critical pathogens, including S. aureus, non-aureus Staphylococcus, and S. agalactiae. Overall, the results obtained with the evaluated chromogenic culture system support its use as an effective on-farm screening tool for milk samples. This approach can assist dairy producers and veterinarians in making timely treatment decisions, particularly by supporting more judicious antimicrobial use and contributing to antimicrobial stewardship in dairy herds.
tese
Genótipos de arroz de terras altas em ambiente de sucessão de culturas
(Universidade Federal de Lavras, 2026-08-14) Mulhanga, Arsénio Daniel Ivo; Botelho, Flávia Barbosa Silva; Gonçalves, Adenilson Henrique; Guedes, Janine Magalhães; Rezende, José Luís de Andrade; Azedo, Sebastião Marcio de
Grain production systems in Brazil are predominantly based on the soybean - maize succession, a model that, although highly productive, presents limitations associated with low agroecosystem diversification and increased vulnerability to environmental conditions. In this context, upland rice has emerged as a promising alternative for diversifying agricultural production systems, particularly during the second crop season. This thesis aimed to evaluate the potential of upland rice for cultivation during the second crop season through a literature review and the phenotyping of elite breeding lines to identify productive, early-maturing, widely adapted, and stable genotypes across different sowing dates. The thesis was organized into two chapters. The first chapter consisted of a literature review addressing the integration of upland rice into production systems, highlighting its agronomic, environmental, and economic benefits. The second chapter comprised the phenotypic evaluation of elite breeding lines conducted during the 2023, 2024, and 2025 second crop seasons under different sowing dates. The AMMI, GGE Biplot, WAASB, and WAASBY methodologies were employed to assess genotype adaptability and stability. The results revealed substantial genetic variability, enabling the identification of genotypes with high grain yield potential, earliness, broad adaptability, and high stability. The integration of these methodologies improved the accuracy of genotype recommendations for different cultivation conditions. Overall, the findings demonstrate that the inclusion of upland rice in the second crop season is a promising strategy for diversifying production systems, enhancing agricultural sustainability, and supporting breeding programs as well as cultivar recommendations for different environments, particularly under second growing season conditions.
Dados de pesquisa
BT 137 - Primeiro relato de alterações morfológicas induzidas por halauxifeno-metílico em híbridos de canola (Brassica napus L. var. oleifera) no Brasil
(2026-09-11) Guilherme Vieira Pimentel; Natalia Costa; Kevin Augusto Chaves Fernandes
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tese
Evolução do perfil proteometabolômico de pseudofrutos de Hovenia dulcis: do desenvolvimento ontogenético à extração e aplicação in vivo de polissacarídeos
(Universidade Federal de Lavras, 2026-07-10) Machado, Gilson Gustavo Lucinda; Vilas Boas, Eduardo Valério de Barros; Vilas Boas, Brígida Monteiro; Carvalho, Elisângela Elena Nunes; Santos, Ingrid Alves; Antunes, Maria Dulce
Given the limited knowledge regarding the molecular mechanisms underlying the development of Hovenia dulcis in Brazil and the technological potential of its biological matrices, this study aimed to investigate pseudofruit development through an integrated multi-omics approach and to extract, characterize, and apply its polysaccharides (HDPs-BR) as edible coatings for the postharvest preservation of strawberries. Pseudofruit development was characterized through physical, physicochemical, chemical, and high-resolution proteomic analyses across seven developmental stages. In parallel, HDPs-BR extracted from mature pseudofruits were characterized and applied either alone or in combination with sodium alginate (SA) and eugenol (Eug) to strawberries stored for 15 days. The development of Hovenia dulcis extended over 180 days, with effective ripening occurring at 150 days after anthesis, characterized by pronounced softening, pectin solubilization, and the conversion of starch into sugars. Proteomic analyses identified 496 proteins, of which 222 were differentially expressed, revealing the coordinated involvement of energy metabolism, photosynthetic pathways, ethylene signaling, and antioxidant defense mechanisms. Multivariate analysis distinguished three developmental phases chemical defense, metabolic transition, and sensory maturation and revealed that the transition was coordinated by physiological, physicochemical, and metabolic changes. HDPsBR showed an extraction yield of 5.31% and were primarily composed of total sugars (62.68%) and uronic acids (24.95%). They also contained phenolic compounds and exhibited antioxidant activity, demonstrating their bioactive nature. In strawberries, coating performance depended on both formulation and storage period. HDPs-BR at 0.5% favored firmness retention, whereas HDPs-BR at 1% contributed to the retention of phenolic compounds, anthocyanins, and red coloration. The incorporation of SA and Eug provided additional benefits, with HDPs-BR 1% + Eug 0.1% standing out for maintaining red coloration, high anthocyanin content, and antioxidant activity. The coatings also contributed to microbiological control during storage. In conclusion, Hovenia dulcis development is supported by a coordinated proteometabolic network that redirects resources from protective mechanisms toward the acquisition of ripening-associated traits, while its polysaccharides represent a promising bioactive matrix for the development of edible coatings aimed at the sustainable preservation of fresh fruits.
Artigo
Immunophenotypic analysis of t lymphocytes and cytokine production in elderly practicing physical activities and its relationship with quality of life and depression
(2022-09-22) Carvalho-Costa, Tamires Marielem de; Carmo Neto, José Rodrigues do; Teodoro, Anna Glória Fonseca; Soares, Flávia Zero; Rochael, Luiza Pimenta; Assunção, Thaís Farnesi Soares de; Souza, Beatriz Coutinho de; Matos, Beatriz Sodré; Santos, Paula Degani Ferreira dos; Silva, Djalma Alexandre Alves; Machado, Juliana Reis; Silva, Paulo Roberto da; Tiburcio-Costa, Monique Gomes Salles; Oliveira, Carlo José Freire de; Rodrigues Júnior, Virmondes; Rodrigues, Denise Bertulucci Rocha; Silva, Marcos Vinícius da
Aging is a complex process often associated with a chronic inflammatory profile that alters several biological functions, including the immune system and cognitive and physical capacity. The practice of physical activity is increasingly gaining popularity as a method of preventing infections, depression, and other disorders that affect the quality of life of the elderly. Thus, this work analyzes the profile of cytokines and molecular markers expressed in immune cells of elderly people who practice physical activities or not, evaluating their impacts on the immune system and quality of life. For this, 48 individuals were recruited, and peripheral blood samples were collected for hemogram analysis, cytokine determination, and immunophenotyping. Elderly people were separated into two groups: practitioners with low-intensity physical activity and non-practitioners. Quality of life was assessed using the Whoqol-Old instrument, and depression was assessed using the Beck II Depression Inventory. When comparing the scores of the Whoqol-Old and Beck questionnaires, we observed a significant negative correlation between these two factors. The perception of a higher quality of life was present in the elderly who exercised and was related to greater autonomy and sensory abilities, whereas the presence of depression was lower. In the hemogram, we observed higher basophil and segmented counts in the sedentary elderly, whereas lymphocytes and monocytes had lower counts. Elderly practitioners of physical activities had higher levels of IFN-γ, IL-4, and IL-10; increased expression of CD69, PD1, and TIM-3 in CD4+ T lymphocytes and increased CD14+CD80+ and CD14+CD86+ monocytes. Elderly people with an increased perception of quality of life had higher levels of IFN-γ, higher expression of CD14+CD80+CD86+, and decreased levels of TRAIL. An increase in TRAIL was observed in individuals with depression, in addition to an increased expression of CD14+CD86+. These results show a clear correlation between the quality of life, level of depression, physical activity, and immune system function. Although some cytokines with a typical proinflammatory profile (IFN-γ) were observed, the results point to a protective state with benefits reflected in the general well-being of the elderly who exercise.