DSpace Collection:

Avaliação do crescimento de duas cepas de acidobacterias em meio com quitina

Thu, 30 Jul 2026 00:00:00 GMT

Title: Avaliação do crescimento de duas cepas de acidobacterias em meio com quitina

Avaliação biológica e química de extratos brutos de Hedychium coronarium: atividade antibacteriana e antioxidante

Fri, 13 Mar 2026 00:00:00 GMT

Title: Avaliação biológica e química de extratos brutos de Hedychium coronarium: atividade antibacteriana e antioxidante Abstract: The search for new bioactive compounds from plant matrices is fundamental for combating bacterial resistance and oxidative stress. This study aimed to evaluate the phytochemical, antioxidant, and antimicrobial potential of methanolic extracts from the leaves and flowers of Hedychium coronarium. The methodology consisted of obtaining extracts through ultrasound-assisted maceration, followed by the quantification of total phenolic compounds and the evaluation of antioxidant activity using ABTS radical scavenging and Reducing Power methods. Antibacterial activity was tested using the disc diffusion method against Staphylococcus aureus and Escherichia coli strains. The results demonstrated that the leaf extract has a higher phenolic content compared to the flowers, reflecting superior antioxidant activity. In the Reducing Power assay, leaves showed 223.78 mg EBHT/100g and flowers 112.89 mg EBHT/100g, revealing statistically significant differences (p<0.05) by the Scott-Knott test. A clear dose-dependent behavior was observed, in which increasing concentrations led to an increase in absorbance. Regarding antimicrobial activity, no inhibition zones were observed. The discussion indicates that the absence of zones may be related to the low diffusibility of the crude compounds in the solid agar matrix and not necessarily to biological inactivity. It is concluded that the aerial parts of H. coronarium show relevant antioxidant potential, with the leaf fraction being the most promising.

Avaliação da capacidade de solubilização de fosfato orgânico por acidobacteria AB23 e AB60

Wed, 29 Jul 2026 00:00:00 GMT

Title: Avaliação da capacidade de solubilização de fosfato orgânico por acidobacteria AB23 e AB60 Abstract: Phosphorus is the second most important macronutrient for plants, being associated with several biological processes, but its availability in soluble form in the soil is reduced due to its great capacity to chelate other minerals. A sustainable way to provide soluble phosphorus to plants is through phosphate-solubilizing microorganisms, which possess mechanisms that transform insoluble phosphorus, such as the release of phosphatase enzymes. These enzymes have a subgroup called phytases, which perform the solubilization process using phytate as a substrate, a form of organic phosphorus widely present in the soil. Acidobacteria is a recently discovered phylum, present in large quantities in Cerrado soils, and the hypothesis of this work is that the AB23 and AB60 strains, isolated from these soils, participate in phosphorus cycling through phytate solubilization by the release of phytases. For this purpose, the strains were cultivated in standard VL-55 culture medium, phosphorus-free medium, and medium containing phytate as a phosphorus source, using serial dilutions for statistical analyses of bacterial growth by colonyforming unit counts. During the work, modifications were made to the experiment to improve the results obtained. Additionally, both strains were also cultivated in modified Pikovskaya medium containing phytate, in order to evaluate the presence of phytases through the formation of a solubilization halo. After cultivation and growth for 4 weeks at 28°C under the presence of light, following the changes made to the methodology, strain AB23 showed growth up to 10⁻⁸ in the standard medium, 10⁻⁶ in the modified medium, and 10⁻⁸ in the negative control, with subsequent cell death. Strain AB60 showed growth up to dilution 10⁻⁷ in the positive control, 10⁻⁴ in the modified medium, and 10⁻⁵ in the negative control. Statistical analyses showed that both strains had statistically lower growth than their positive controls, but AB23 had higher growth than the phosphorus-free medium, while AB60 had statistically equivalent growth. Neither strain showed growth in Pikovskaya medium at any of the phytate concentrations. The present study demonstrated the need for further future experiments to confirm the results regarding strain AB60, and that AB23 has the capacity to solubilize organic phosphorus in the form of phytate, indicating its participation in phosphorus cycling in Cerrado soils and its potential use as a bioinput to make phosphorus available to plants.

Novos compostos da classe dos benzotiazóis: atividades biológicas e alterações moleculares em células tumorais mamárias triplo-negativas

Wed, 29 Jul 2026 00:00:00 GMT

Title: Novos compostos da classe dos benzotiazóis: atividades biológicas e alterações moleculares em células tumorais mamárias triplo-negativas Abstract: Breast cancer is the most commonly diagnosed malignant tumor among women worldwide. Different therapeutic strategies are employed, and for its most aggressive subtype, triple-negative breast cancer (TNBC), chemotherapy remains the main clinical approach. However, the toxicity of the drugs used, the activation of resistance mechanisms, and recurrence rates remain major concerns. In this context, the search for new compounds is urgent, and benzothiazole-derived compounds have stood out due to their ability to modulate the redox and inflammatory status of cells. The present study aimed to evaluate the effects of nine novel compounds from this class in BC cell lines through cytotoxicity, clonogenicity, migration, and qPCR assays. Human non-tumoral cell lines HFF-1 (fibroblast) and MCF 10A (breast), as well as the tumor cell lines MCF7 (luminal BC) and MDA-MB-231 (triple-negative BC), were cultured. Among the tested compounds, only compound 2 showed activity and selectivity, with an IC50 = 12.26 µM and a selectivity index (SI) > 2.0. In addition, it significantly inhibited the clonogenicity and migration of triple-negative cells after 48 hours of treatment with 3.07 µM (IC50/4) and 6.13 µM (IC50/2) of 2. Finally, qPCR assays demonstrated that the compound 2 modulates the transcripts of IL6, TGFβ, KRT18, and VIM. Therefore, we suggest that compound 2 modulates the epithelial–mesenchymal transition process in TNBC cells, thereby controlling their aggressiveness. Additional studies are required to validate other EMT-related targets, including animal models.