Improved natural melanin production by Aspergillus nidulans after optimization of factors involved in the pigment biosynthesis pathway.

BACKGROUND: Melanin is a natural pigment that can be applied in different fields such as medicine, environment, pharmaceutical, and nanotechnology. Studies carried out previously showed that the melanin produced by the mel1 mutant from Aspergillus nidulans exhibits antioxidant, anti-inflammatory, and antimicrobial activities, without any cytotoxic or mutagenic effect. These results taken together suggest the potential application of melanin from A. nidulans in the pharmaceutical industry. In this context, this study aimed to evaluate the effect of factors L-tyrosine, glucose, glutamic acid, L-DOPA, and copper on melanin production by the mel1 mutant and to establish the optimal concentration of these factors to maximize melanin production. RESULTS: The results showed that L-DOPA, glucose, and copper sulfate significantly affected melanin production, where L-DOPA was the only factor that exerted a positive effect on melanin yield. Besides, the tyrosinase activity was higher in the presence of L-DOPA, considered a substrate required for enzyme activation, this would explain the increased production of melanin in this condition. After establishing the optimal concentrations of the analyzed factors, the melanin synthesis was increased by 640% compared to the previous studies. CONCLUSIONS: This study contributed to elucidating the mechanisms involved in melanin synthesis in A. nidulans as well as to determining the optimal composition of the culture medium for greater melanin production that will make it possible to scale the process for a future biotechnological application.

Unlocking the biosynthetic potential and taxonomy of the Antarctic microbiome along temporal and spatial gradients.

Extreme environments, such as Antarctica, select microbial communities that display a range of evolutionary strategies to survive and thrive under harsh environmental conditions. These include a diversity of specialized metabolites, which have the potential to be a source for new natural product discovery. Efforts using (meta)genome mining approaches to identify and understand biosynthetic gene clusters in Antarctica are still scarce, and the extent of their diversity and distribution patterns in the environment have yet to be discovered. Herein, we investigated the biosynthetic gene diversity of the biofilm microbial community of Whalers Bay, Deception Island, in the Antarctic Peninsula and revealed its distribution patterns along spatial and temporal gradients by applying metagenome mining approaches and multivariable analysis. The results showed that the Whalers Bay microbial community harbors a great diversity of biosynthetic gene clusters distributed into seven classes, with terpene being the most abundant. The phyla Proteobacteria and Bacteroidota were the most abundant in the microbial community and contributed significantly to the biosynthetic gene abundances in Whalers Bay. Furthermore, the results highlighted a significant correlation between the distribution of biosynthetic genes and taxonomic diversity, emphasizing the intricate interplay between microbial taxonomy and their potential for specialized metabolite production.IMPORTANCEThis research on antarctic microbial biosynthetic diversity in Whalers Bay, Deception Island, unveils the hidden potential of extreme environments for natural product discovery. By employing metagenomic techniques, the research highlights the extensive diversity of biosynthetic gene clusters and identifies key microbial phyla, Proteobacteria and Bacteroidota, as significant contributors. The correlation between taxonomic diversity and biosynthetic gene distribution underscores the intricate interplay governing specialized metabolite production. These findings are crucial for understanding microbial adaptation in extreme environments and hold significant implications for bioprospecting initiatives. The study opens avenues for discovering novel bioactive compounds with potential applications in medicine and industry, emphasizing the importance of preserving and exploring these polyextreme ecosystems to advance biotechnological and pharmaceutical research.

Toxicity treatment of tobacco wastes using experimental design by filamentous fungi.

Cigarette product waste contains toxic chemicals, including human carcinogens, which leach into and accumulate in the environment and represent a current environmental problem neglected for too long. This study aimed to select filamentous fungi capable of decreasing tobacco extract toxicity as an alternative to a future bioremediation process. The 38 isolates obtained from Culture collection of microorganisms to biotechnological and environmental importance - CCMIBA (Brazil) were cultivated in yeast extract (10 g.L-1) and dextrose (10 g.L-1) containing cigarette tobacco extract (200 mL.L-1) for seven days at 28 °C on a rotary shaker at 150 rpm. The fungal growth rate was determined to infer fungal tolerance to tobacco extract, and supernatants from cultivated fungi were used to run the toxicity test using Allium cepa assay. The Fusarium sp. strain I.17, isolated from cigarette waste, was the only lineage capable of growing in 20% (v/v) of cigarette tobacco extract, allowed the onions to root, and was selected for optimization. Initially, for the experimental design to selected fungus, a fractional factorial experimental design 25-1 was used to examine the effects of yeast extract, cigarette tobacco extract concentration, dextrose, copper sulfate and pH fungal cultivation. The supernatants of these assays were used to run the toxicity test, and yeast extract and copper sulfate were statistically significant in the fungal growth for the decreasing toxicity process and this variable as were select to central composite design. The highest concentration of yeast extract negatively influenced the toxicity decrease, 0.5% of yeast extract in the culture media is the maximum concentration to achieve the best result and to copper sulfate the best result was using 10 µmol.L-1. In conclusion, the experimental design optimized more than seven times the efficiency of tobacco toxicity reducing, resulting in more than 50% of onion root growth, demonstrating the methodology success. And ITS region was used to taxonomy and molecular phylogeny of the isolate Fusarium sp. strain I.17. These results suggest that Fusarium sp. strain I.17 can be used as a potential microorganism to toxicity treatment of cigarette wastes, minimizing the environmental impact of direct burning.

Urban forest fragments as unexpected sanctuaries for the rare endemic ghost butterfly from the Atlantic forest.

Anthropogenic land expansion, particularly urbanization, is pervasive, dramatically modifies the environment and is a major threat to wildlife with its associated environmental stressors. Urban remnant vegetation can help mitigate these impacts and could be vital for species unable to survive in harsh urban environments. Although resembling nonurban habitats, urban vegetation remnants are subject to additional environmental stresses. Here, we evaluate the occurrence and density of the endemic ghost butterfly (Morpho epistrophus nikolajewna) that was once common, in the highly fragmented Atlantic forest of NE Brazil. We tested whether this butterfly would be found at lower densities in urban forest fragments of contrasting sizes as opposed to rural ones, given the number of environmental stressors found in urban areas. We surveyed 14 forest fragments (range 2.8 to over 3,000 ha) of semideciduous Atlantic forest in rural and urban locations using transect based distance sampling. The ghost butterflies showed strong seasonality; flying only from April to June. They were only identified in an urban fragment (515 ha), with an estimate of 720 individuals and a density 1.4 ind/ha. All forest fragments had experienced some level of logging in the past, which might have had an effect in the butterfly population. Nevertheless, rural forest fragments were subject to increased particulate matter concentrations, associated to biomass burning that we suggest might have had a more influential role driving the collapse of rural populations. Our findings show the importance of urban forest remnants to sustain population of this endangered species.

Frequência populacional de Dermatobia hominis (Linnaeus Jr., 1781) (Diptera: Cuterebridae) e sua correlação com variáveis climáticas, no Sudeste do Brasil / Population variations of Dermatobia hominis (Linnaeus Jr., 1781) (Diptera: Cuterebridae) and correlation with variable climate in southeast Brazil

Dermatobia hominis infestation in dairy cattle was investigated, searching for the existence of correlations between the incidence of botfly and climatic factors (temperature, relative humidity, and rainfall) and its distribution on the animal body surface. Two geographical areas located in the southeast region of Brazil were selected. Area 1- tropical and sub-tropical climate of altitude (Cwa); Area-2 tropical climate (Aw). During the period from May to December 2013, 10 animals were selected in each area and biweekly field collections were carried out for quantification of the average number of larvae in the herd. Larval nodes were registered during every month of the survey. Area 1 had an average of 12.94 larvae/month and Area 2 an average of -7.58 larvae/month. No correlation between the number of larvae and the climatic variables (p > 0.05) was found in Area 2. A positive correlation between the average number of larvae and the temperature (p = 0.011) and precipitation (p = 0.034) was found in Area 1. These climatic factors are related to soil characteristics, influencing the penetration of L3 larvae and the pupal period. The greatest number of nodules was found in the anterior inferior region, followed by the anterior superior region of the animal body. The infestation in these regions deserves a special emphasis because these are the regions comprising the part of the animals hides which can be industrialized, and thus represent the largest cause of economic losses...

Foi avaliada a frequência de infestação por larvas de Dermatobia hominis em bovinos leiteiros, investigando-se a existência de correlação entre a incidência do berne e os fatores climáticos (temperatura, umidade relativa e precipitação pluviométrica) com a sua distribuição na superfície corporal dos animais. Foram selecionadas duas áreas localizadas na região Sudeste do Brasil: Área 1: clima subtropical/tropical de altitude (Cwa); Área 2: clima tropical (Aw). As observações foram realizadas no período de maio a dezembro de 2013. Em cada propriedade foram examinados dez animais em coletas de campo quinzenais para o levantamento do número de nódulos de berne. Foram registrados nódulos durante todos os meses de coleta. A Área 1 apresentou média de 12,94 bernes/mês, e a Área 2, 7,58 bernes/mês. Na Área 2, não foi constatada a existência de correlação entre o número de bernes e as variáveis climáticas (p > 0,05). Na Área 1, houve correlação entre o número médio de bernes com a temperatura (p = 0,011) e a precipitação (p = 0,034). Esses fatores climáticos, relacionados às características edáficas, influenciam a penetração das larvas L3 e o período pupal. O maior número de nódulos foi encontrado na região anterior inferior, seguida pela região anterior superior do corpo dos animais, regiões nobres que compõe a parte industrializável da pele do animal e que representam a maior causa de prejuízo econômico...