Brazilian Journal of Biology最新文献

Erysimum croceum is a rare, endemic, and medicinally valuable plant listed in Kazakhstan's Red Data Book. Employing modern geobotanical and floristic, soil methods, four natural populations of the rare endemic species Erysimum croceum were identified and comprehensively assessed in the Zailiyskiy Alatau region of the northern Tien Shan. The studied populations are located in distinct ecological settings: one in the Big Almaty gorge, two on the opposite banks of the Small Almaty gorge, and one in the Issyk gorge. Comprehensive field surveys were conducted to characterize their plant communities, population structure, and soil properties. The presence of flowering and fruiting individuals indicates that these populations currently maintain reproductive viability within the protected spruce forest belt at elevations of 1,724-2,597 m a.s.l. However, the absence of juvenile and immature individuals in three of the four populations indicates limited regeneration and classifies them as regressive, which could pose a risk of gradual decline. Comparative soil analyses revealed notable differences: mountain dark forest soils of populations 1 and 2 showed moderate organic matter (up to 12.7%) and favorable nutrient levels, while population 4 demonstrated the highest ecological potential, with humus content up to 32.16% and a fine dusty loam texture supporting high water retention and biodiversity. The population near Issyk gorge is particularly vulnerable to the pressure of tourism. Implement long-term demographic monitoring across all sites, regulate visitor access and protect high-quality microsites (notably near Issyk), and establish ex-situ safeguards through seed banking and botanical-garden cultivation; restoration should target humus-rich, medium-loam reference conditions. This study provides the first integrated eco-phytocoenotic and edaphic assessment across four E. croceum populations in the Northern Tien Shan, quantitatively linking soil heterogeneity to population status and delivering site-specific conservation guidance.

Hancornia speciosa (Apocynaceae) trees are valuable for several communities that survive from collecting their fruits. However, H. speciosa is threatened due to the increasing deforestation in the Brazilian Cerrado. This study aimed to identify the loss and solution sources, and their importance in terms of loss or income gain on H. speciosa trees applying the Percentage of Importance Indice (% I.I.). The % I.I. separated the loss sources [e.g., sap-sucking Phenacoccus madeirensis on leaves = 46.25%)] on the percentage of reduction of fruit production (e.g., 0.004%), calculated the attention level (e.g., 0.0937/leaf), with a total lost production of 0.02% (≈ 24 total lost fruits). The solution sources spiders, predator thrips Holopothrips sp., and Chrysoperla sp. showed the highest % I.I. on H. speciosa trees, increasing system productivity by 0.01% (≈ 16 total saved fruits). Spiders were the most important predator group, saving 13 fruits (I.G.=0.009%) and the tending ants reduced around 0.19 fruits (I.G.=-0.0003%). The loss sources and ants are not harmful to H. speciosa trees on the natural system - Cerrado, but, in future commercial crops (e.g., monoculture), they can cause significant damages to fruit production.

Myricetin (ME) is a flavonoid found in various plant-based foods, recognized for its anti-inflammatory, antioxidant, and anticancer properties. This study evaluated the antiproliferative and antimutagenic potential of ME, both isolated and in combination with the chemotherapeutic agent oxaliplatin (OXL), using in vitro models. Cytotoxicity was assessed in the NCI-H460 non-small cell lung cancer cell line via the MTT assay, while the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay was performed in CHO-K1 non-tumoral cells to investigate chromosomal instability and cytostasis. ME at concentrations of 5 and 10 µM significantly reduced the viability of NCI-H460 cells, demonstrating a cytotoxic effect. OXL alone also reduced cell viability; however, when combined with ME, this effect was attenuated, suggesting a protective or antagonistic interaction. In CHO-K1 cells, ME did not modulate cytostasis induced by OXL in any treatment protocol. Regarding genotoxicity, ME failed to reduce chromosomal damage markers (micronuclei, nucleoplasmic bridges, and nuclear buds) when administered before or simultaneously with OXL. Interestingly, post-treatment with ME significantly increased the frequency of micronuclei induced by OXL, indicating a potentiating effect. These findings suggest that although ME possesses antiproliferative activity against tumor cells, it may also interfere with the efficacy of OXL depending on the treatment schedule. The results contribute to understanding the dual role of phytochemicals in chemotherapy, emphasizing the importance of evaluating timing and interaction in combination therapies.

[This corrects the article doi: 10.1590/1519-6984.297965].

Balancing insecticide use and the conservation of the honey bee Apis mellifera in agricultural areas is a challenge for farmers, especially where bee colonies are introduced. For this reason, it is important to evaluate the toxicity of insecticides used for pest control. This study aimed to assess the toxicity levels of the insecticides Chlorantraniliprole and Cyantraniliprole, both from the anthranilic diamides group, on the survival and flight ability of Africanized honey bees. The experiment was conducted in a laboratory, testing five commercial doses of Chlorantraniliprole (0.015, 0.05, 0.1, 0.2, 0.3 g a.i./L) and Cyantraniliprole (0.015, 0.02, 0.04, 0.05, 0.1 g a.i./L) in two ways of exposure: direct spray onto the bees and ingestion of contaminated diet. Both insecticides caused low mortality regardless of exposure method and dose, but Cyantraniliprole was more toxic when ingested. Flight ability was affected by the insecticides through direct spray at higher doses. Although considered low-risk, direct exposure to these insecticides affected the flight ability of A. mellifera.

Diabetes mellitus is a global public health issue and, at the onset of the COVID-19 pandemic, was identified as a risk factor associated with high morbidity and mortality in cases of acute respiratory infection caused by the SARS-CoV-2 coronavirus. This study investigated genetic variants in diabetic patients with COVID-19 through a systematic analysis of the PubMed/NCBI, EMBASE, Web of Science, SCOPUS, and Virtual Health Library databases, with the protocol registered on the PROSPERO platform (registration number CRD42020181311). Fifteen genetic variants were associated with five specific genes in symptomatic diabetic patients with COVID-19. Inheritance models, diabetic individuals carrying the heterozygous genotype TC (VDR rs4516035) showed ~10-15-fold higher odds of symptomatic COVID-19. Protein-protein interaction (PPI) analysis showed that the proteins ACE, ACE2, IL-6, and IL-17 exhibited strong predicted interactions with each other, as well as with insulin and the TMPRSS2 protease. Limitations include small number of eligible studies, heterogeneity in populations and outcome definitions. These preliminary findings highlight the need for further studies to understand better the relationship between the identified genetic variants and the progression of COVID-19 in diabetic patients.

Brazilian biodiversity is rich in compounds with biological potential. Propolis is a natural product formed from bee saliva and plant exudates. Brazilian brown and green propolis exhibit antioxidant, antibacterial, antifungal, antiviral, and antiparasitic activities. These properties arise from their rich phenolic content; molecules such as artepellin-C, quercetin, and kaempferol are important phenolic biomolecules described in propolis. The objective of this study was to determine the antifungal activity and chemical parameters of brown and green propolis samples commercialized in Santa Rita do Sapucaí, southern Minas Gerais, Brazil. The total phenolic compound content was assessed using the Folin-Ciocalteu colorimetric method. Total flavonoid concentration was determined by the aluminum chloride complexation method. The pH and density were also determined. The antifungal activity of the extracts was evaluated using the disk diffusion technique against strains from the American Type Culture Collection (ATCC), following the Kirby-Bauer methodology. Both extracts showed similar densities; the green propolis extract presented a pH of 4.37, while the brown propolis extract showed a pH of 3.61. The ethanolic extract of brown propolis (706.79 mg GAE/g) exhibited a higher content of phenolic compounds compared to green propolis (697.65 mg GAE/g), whereas the green propolis extract (415.75 mg QE/g) presented a higher flavonoid content than brown propolis (378.75 mg QE/g). Clinically relevant strains, Candida albicans (EPM: 12.43 mm; EPV: 12.78 mm), Candida parapsilosis (EPM: 14.88 mm; EPV: 13.96 mm), and Cutaneotrichosporon dermatis (EPM: 11.95 mm; EPV: 12.28 mm), were the most susceptible to both extracts. It can be inferred that the extracts possess excellent antifungal activity, possibly associated with their rich phenolic and flavonoid content.

Cerrado is Brazil's second largest biome, and its fauna and flora are rich in biodiversity. As a result, many plants are being studied to find new viable drugs. Among the species of interest is Hymenaea courbaril, commonly known as "jatobá". In this scenario, the extract's standardization and the execution of in vitro studies are crucial steps before investigating its applicability in human beings. This study aimed to obtain a standardized liquid extract of Hymenaea courbaril stem bark and analyze its phytochemical, antimicrobial, and cytotoxic profiles. The extract proved viable in RAW 264.7 cells and inhibited the bacterial growth of a methicillin-resistant Staphylococcus aureus (MRSA) clinical isolate. After High-Performance Liquid Chromatography (HPLC) screening, peaks suggestive of catechin and epicatechin were found. In silico analysis of these flavonoids indicated an LD50 of 10000 mg/kg, fulfillment of Lipinski's criteria, and both were classified as druglike, with a safety level of 6. In conclusion, the standardized liquid extract of Hymenaea courbaril stem bark is non-toxic and rich in catechin and epicatechin. It has antimicrobial action against Staphylococcus aureus, opening up prospects for in vivo studies.

The bacterial growth curve graphically represents the development of a bacterial population over time. This analysis is essential to optimize efficiency in research with microorganisms. The research aimed to identify the temperature and time at which bacterial growth reaches the stationary phase and obtain the point of maximum performance. Four species of growth-promoting bacteria were evaluated: Pseudomonas fluorescens, Bacillus aryabhattai, Bacillus subtilis and Azospirillum brasilense, subjected to temperatures of 25 °C, 30 °C and 35 °C. The bacteria were inoculated in a nutrient solution and incubated in a water bath. Samples were taken at four-hour intervals for serial dilution and plating. The colony-forming units (CFUs) were counted every 12 hours. Pseudomonas fluorescens showed maximum growth at 29.9 °C and 52.3 hours. Bacillus aryabhattai reached maximum growth at 25 °C in 48 hours. Bacillus subtilis had maximum growth at 24.1 °C and 47.2 hours. Azospirillum brasilense reached maximum growth at 25.9 °C and 42.5 hours. The results indicate that temperature variations significantly influence the growth of the bacteria analyzed. Based on this research, it is possible to adjust laboratory methodologies to improve the efficiency of microorganism production processes.

The biomass of the unicellular green microalga Parachlorella kessleri is considered as one of the valuable sources of easily digestible protein, polysaccharides, pigments, and high-molecular fatty acids in the composition of synthesized lipids. The quality and quantity of these compounds vary based on intraspecific differences in strains, as well as growing conditions. Nitrogen is one of the most critical nutrients affecting cell growth and biochemical composition of microalgae, ultimately determining the lipid productivity for biofuels. In order to investigate the effect of nitrogen sources on newly isolated microalga Parachlorella kessleri MDC 6524 cell growth, lipid synthesis, and fatty acid composition, the strain was simultaneously grown on wastewater-simulating nutrient medium with and without a nitrogen source in bubble column photobioreactors. After 14 days of cultivation in the medium devoid of nitrogen sources, the total fatty acid content was 31.2% of the dry weight of the biomass, while in the medium rich in nitrogen sources, the fatty acid content was only 12.5%. Two methods for producing biodiesel were investigated: (i) lipid extraction followed by transesterification and (ii) direct transesterification from algal biomass. As a result, lipid extraction followed by transesterification increased biodiesel yield (per unit of biomass) by 1.2 times compared to the direct transesterification method. However, the direct transesterification method is significantly less time-consuming. Despite this advantage, the method has some limitations due to the interaction of lipids with the acid catalyst used in the process.