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Cell differentiation in cyanobacteria desmonostoc Sp. under different phosphorus concentrations and its potential as a growth promoter for the aquatic macrophyte Salvinia Auriculata
(Universidade Federal de Lavras, 2025-08-27) Pimenta, Larissa Langsdorff; Coelho, Flávia de Freitas; Ferreira, Guilherme Ramos Demetrio; Biondi, Michel; Reis, Kelly Cristina dos; Souza, Grécia de Andrade
Cyanobacteria and aquatic macrophytes are organisms that perform important ecosystem services and influence the dynamics of the ecosystems in which they occur. Both can positively or negatively affect their environments, depending on local conditions. Cyanobacteria carry out oxygenic photosynthesis, and some are capable of fixing atmospheric nitrogen, making it bioavailable to other organisms. Among nitrogen-fixing cyanobacteria, heterocytous strains are able to differentiate specialized cells heterocytes and akinetes. Heterocytes are specialized in nitrogen (N) fixation, while akinetes store reserves and enter dormancy under adverse conditions, providing adaptive advantages by enabling survival in stressful environments. Cell differentiation is genetically regulated and influenced by environmental factors, such as nutrient availability. Nitrogen limitation is a known trigger for differentiation, but phosphorus (P), a macronutrient involved in various metabolic processes may also play a crucial role. Variations in P availability can trigger the differentiation of both heterocytes and akinetes. Cyanobacteria can influence other organisms by forming endophytic or epiphytic associations, providing fixed nitrogen to their hosts and potentially promoting plant growth. Aquatic macrophytes, such as Salvinia auriculata, can harbor a diversity of cyanobacteria that may contribute to their growth. Given this context, we evaluated cell differentiation in the cyanobacterium Desmonostoc sp. UFLA12 under different phosphorus concentrations. We then inoculated this strain into a medium with S. auriculata to assess its potential to promote macrophyte growth. We found that phosphorus availability influenced heterocyte production and akinete differentiation in Desmonostoc sp. UFLA12. Moreover, this strain enhanced the clonal growth of S. auriculata. We conclude that phosphorus availability affects cellular differentiation in Desmonostoc sp. UFLA12, and that its inoculation contributes to the rapid and vigorous spread of S. auriculata, even in oligotrophic environments.
Influência de revestimentos à base de proteínas do soro lácteo e amido de mandioca, adicionados de curcumina e própolis, em queijo Minas Padrão
(Universidade Federal de Lavras, 2025-08-22) Mussalafo, Cháid Acácio António; Abreu, Luiz Ronaldo de; Piccoli, Roberta Hilsdorf; Carvalho, Elisangela Elena Nunes; Ointo, Sandra Maria; Boari, Cleube Andrade
In Brazil, Minas cheeses represent approximately 10% of national production, with the standard type being more durable than the fresh type due to ripening. However, during this process, physicochemical and microbiological changes can occur due to oxidation and the action of microorganisms such as Listeria monocytogenes. In this context, edible films and coatings represent a promising alternative, as they offer similar protection to synthetic films, with the advantage of being biodegradable and environmentally sustainable. Therefore, this research aimed to investigate the technological performance of edible films and coatings made from whey proteins and cassava starch, with added curcumin and propolis, applied to Minas Padrão cheese, to evaluate their effectiveness and potential use in preserving and improving product quality. To achieve these objectives, curcumin and propolis were evaluated for the presence of phenolic compounds, antioxidant activity, and in vitro antimicrobial activity against L. monocytogenes. From film-forming solutions of whey proteins and cassava starch, coatings S1 (starch-based), S2 (a mixture of starch and whey protein concentrate), and S3 (whey protein concentrate-based) were prepared and characterized by their rheological properties (apparent viscosity and viscoelasticity). Using the same film-forming solutions (S1, S2, and S3), films F1, F2, and F3 were obtained, respectively, and characterized by their water vapor permeability, degradation in water and soil, and contact angle. Cheeses previously inoculated with L. monocytogenes strains were coated and evaluated for moisture, water activity, pH, mass loss, color, and texture after 21 days of ripening. The growth count of L. monocytogenes in the cheeses was performed on days 1, 7 and 14. Propolis showed a higher total phenolic content (215.64 ± 6.40 mg EAG/g) and antioxidant activity (136.6 μmol EAA/g) compared to curcumin (197.26 ± 4.50 mg EAG/g; 83.1 μmol EAA/g). Antimicrobial assays demonstrated inhibition of L. monocytogenes at concentrations of 0.84% curcumin associated with 0.71% propolis, indicating an additive effect of the combinations. The film- forming solutions showed pseudoplastic behavior, with consistency indices (k) ranging from 0.0016 (S3) to 1.8483 (S1) Pa•sn and flow indices (n) between 0.49 and 0.99. The films obtained differed in water vapor permeability, ranging from 3.48 g•m−2•day−1 (F1 – starch) to 7.40 g•m−2•day−1 (F3 – CPS), and water solubility exceeding 40%. When applied to cheeses, the coatings reduced mass loss by up to 12% compared to the control, maintained water activity between 0.91 and 0.93, and a stable pH of around 5.2. After 14 days of ripening, the coated cheeses showed lower L. monocytogenes counts (≈2.5 log CFU/g) compared to the control (≈4.8 log CFU/g).
Uma década de melhoramento do arroz de terras altas em Minas Gerais: do progresso genético aos impactos da interação genótipos × ambientes
(Universidade Federal de Lavras, 2025-10-22) Cardoso, Felipe Pereira; Botelho, Flávia Barbosa Silva; Nunes, José Airton Rodrigues; Andrade Júnior, Válter Carvalho de; Furtini, Isabela Volpi; Rodrigues, Cinthia Souza
The work brings together two complementary studies on upland rice breeding, based on a decade of data from the UFLA Genetic Breeding Program. We analyzed Value for Cultivation and Use (VCU) trials conducted between 2014/15 and 2023/24 across different locations in Minas Gerais, encompassing 74 elite lines evaluated in 26 experimental environments. The first study, using mixed models (REML/BLUP), quantified genetic progress in grain yield: the accumulated gain was ~430 kg ha⁻¹, equivalent to a 13% increase over the program’s baseline. Decomposition indicated that 62% of the gain arose from within-program advancement of superior lines, and 38% from the introduction of new genotypes, evidencing a balanced strategy between exploiting variability and renewing germplasm. Heritability of genotype means increased from ~0.20 to ~0.85, and selection accuracy from 0.45–0.67 to 0.92. The genotype × environment (GE) interaction accounted for 21–83% of phenotypic variance. The second study employed 26 quantitative environmental covariates for stratification. Climatic similarity (Environmental Kinship, KE) identified four mega-environments with significant yield differences among groups (p = 0.003; η² = 0.411). Principal component analysis explained 77.3% of environmental variation: PC1 was associated with water availability and PC2 with thermal conditions. In parallel, the GGE biplot arranged environments into three groups oriented by genotypic response, without consolidated statistical differences (p = 0.323). Global concordance between methods was moderate (42.3%), higher in ME2 (71.4%). Taken together, the findings indicate interannual variability as the dominant driver of GE, repositioning locations in environmental space. Lines G40, G47, G57, and G63 combined high yield and stability and remained under evaluation through the 2023/24 season. Practically, the results support integrating envirotyping and GGE biplot to guide strategic trial allocation, maintaining renewal rates around 30–35%, and applying stability indices within each mega-environment. These approaches provide a robust methodological basis for quantifying genetic progress and environmental stratification, with potential extension to other crops and regions.
De grão em grão, as formigas transformam o chão: uma revisão global sobre o papel das formigas nas propriedades químicas, físicas e biológicas do solo
(Universidade Federal de Lavras, 2025-09-30) Santos, Antonia Heloisa Peixoto dos; Ribas, Carla Rodrigues; Fontenele, Luane Karoline; Lasmar, Chaim José; Leal, Laura Carolina; Souto, Leandro de Sousa
Ants have a crucial role in ecosystems through bioturbation, and such activities exert both direct and indirect impacts on the environment. Despite their ecological importance, a comprehensive global synthesis is still lacking, particularly one that elucidates the effects of these activities on soil properties, identifies the most consistent patterns across studies, and highlights existing research gaps. In this context, the present study compiles and analyzes information available in the scientific literature regarding the effects of ants on the physical, chemical, and biological properties of soils, emphasizing their function as ecosystem engineers, based on a review of studies published between 1945 and 2024. Most investigations employed field and laboratory sampling methods, with a predominant focus on tropical, subtropical, temperate, and boreal forests, as well as pasturelands. Soil moisture, pH, nitrogen content, plant biomass, and microbial biomass emerged as the main parameters assessed. We identified important gaps related to ant–plant interactions, such as whether species were native or exotic to the study areas, in addition to limitations in the description of environmental variables and methodologies, which constrain cross-study comparability. The genera Formica, Atta, and Messor were consistently reported across all databases consulted. Numerous studies found positive influences of ant activities on soil, reinforcing their ecological significance. We suggest that there should be greater standardization of methodologies, for example in the sampling method or in the depths of the samples, as well as in a clearer description of the methods, so that future research can deepen the understanding of these interactions.
Crescimento, morfometria e densidade da madeira de espécies arbóreas em sistema agroflorestal com cafeeiro
(Universidade Federal de Lavras, 2025-07-17) Amuda, Laila Atibo Raúl; Melo, Lucas Amaral de; Sales, Nilza de Lima Pereira; Venturin, Régis Pereira
This work is structured in two parts: the first provides a general overview of the topic studied, while the second comprises three scientific articles. The overall objective of the research was to evaluate the growth, morphometry, and wood density of tree species in an agroforestry system. The study was conducted in an experiment implemented in 2012 on the property of NKG Fazendas Brasileiras, located in the municipality of Santo Antônio do Amparo, Minas Gerais. The second part of the study surveyed variables related to the growth, morphometry, and basic wood density of the tree species evaluated. The first article focused on assessing the growth of the species over time, considering the age range between 4 and 8 years. The main results observed were progressive increases in diameter at breast height (DBH), total height, and volume in all species, with acrocarps showing the greatest increases in all variables analyzed. The second article addressed the morphometry of the species at 12 years of age. Once again, acrocarp presented the highest values for DBH (51.58 cm), height (19.81 m), and crown diameter (12.60 m), demonstrating its high capacity for both vertical and horizontal occupancy. While African mahogany and teak performed worse in these characteristics, the third article evaluated the effect of spacing on the growth and basic wood density of the species. Acrocarp remained the best-performing species, presenting the highest average DBH and volume values at both spacings, unlike African mahogany and teak, which showed lower growth regardless of the spatial arrangement. Basic wood density varied among the species, being higher in acrocarp and lower in teak, but was not influenced by the spacing adopted. Overall, the results obtained across the three articles demonstrate that, among the tree species in the system, acrocarp stood out in all variables evaluated. However, it is concluded that this species represents a promising alternative for agroforestry systems that aim for high productivity, efficient coverage and wood production with superior technological quality and that for its implementation in agroforestry systems, the purpose of planting, the characteristics of each species involved in the system, such as growth dynamics, the effective onset of intraspecific and interspecific competition must be taken into account.