Publications by authors named "Vânia Maria Maciel Melo"

27 Publications

  • Page 1 of 1

Brazilian Semi-Arid Mangroves-Associated Microbiome as Pools of Richness and Complexity in a Changing World.

Front Microbiol 2021 26;12:715991. Epub 2021 Aug 26.

Laboratory of Microbial Ecology and Biotechnology, Department of Biology, Federal University of Ceará (UFC), Fortaleza, Brazil.

Mangrove microbiomes play an essential role in the fate of mangroves in our changing planet, but the factors regulating the biogeographical distribution of mangrove microbial communities remain essentially vague. This paper contributes to our understanding of mangrove microbiomes distributed along three biogeographical provinces and ecoregions, covering the exuberant mangroves of Amazonia ecoregion (North Brazil Shelf) as well as mangroves located in the southern limit of distribution (Southeastern ecoregion, Warm Temperate Southwestern Atlantic) and mangroves localized on the drier semi-arid coast (Northeastern ecoregion, Tropical Southwestern Atlantic), two important ecotones where poleward and landward shifts, respectively, are expected to occur related to climate change. This study compared the microbiomes associated with the conspicuous red mangrove () root soils encompassing soil properties, latitudinal factors, and amplicon sequence variants of 105 samples. We demonstrated that, although the northern and southern sites are over 4,000 km apart, and despite genetic divergences between north and south populations, their microbiomes resemble each other more than the northern and northeastern neighbors. In addition, the northeastern semi-arid microbiomes were more diverse and displayed a higher level of complexity than the northern and southern ones. This finding may reflect the endurance of the northeast microbial communities tailored to deal with the stressful conditions of semi-aridity and may play a role in the resistance and growing landward expansion observed in such mangroves. Minimum temperature, precipitation, organic carbon, and potential evapotranspiration were the main microbiota variation drivers and should be considered in mangrove conservation and recovery strategies in the Anthropocene. In the face of changes in climate, land cover, biodiversity, and chemical composition, the richness and complexity harbored by semi-arid mangrove microbiomes may hold the key to mangrove adaptability in our changing planet.
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http://dx.doi.org/10.3389/fmicb.2021.715991DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8427804PMC
August 2021

Effects of lipopeptide biosurfactants on clinical strains of Malassezia furfur growth and biofilm formation.

Med Mycol 2021 Aug 23. Epub 2021 Aug 23.

Laboratório de Ecologia Microbiana e Biotecnologia (LEMBiotech). Departamento de Biologia, Federal University of Ceara, Avenida Humberto Monte 2977, Fortaleza - CE 60455-760, Brasil.

Lipopeptide biosurfactants (LBs) are biological molecules with low toxicity that have aroused growing interest in the pharmaceutical industry. Their chemical structure confers antimicrobial and antibiofilm properties against different species. Despite their potential, few studies have demonstrated their capability against Malassezia spp., commensal yeasts which can cause dermatitis and serious infections. Thus, the aim of this study was to evaluate the antifungal activity of biosurfactants produced by new strains of Bacillus subtilis TIM10 and B. vallismortis TIM68 against M. furfur and their potential for removal and inhibition of yeast biofilms. Biosurfactants were classified as lipopeptides by FTIR, and their composition was characterised by ESI-Q-TOF/MS, showing ions for iturin, fengycin, and surfactin, with a greater abundance of surfactin. Through the broth microdilution method, both biosurfactants inhibited the growth of clinical M. furfur strains. Biosurfactant TIM10 showed greater capacity for growth inhibition, with no statistical difference compared to those obtained by the commercial antifungal fluconazole for M. furfur 153DR5 and 154DR8 strains. At minimal inhibitory concentrations (MIC-2), TIM10 and TIM68 were able to inhibit biofilm formation, especially TIM10, with an inhibition rate of approximately 90%. In addition, both biosurfactants were able to remove pre-formed biofilm. Both biosurfactants showed no toxicity against murine fibroblasts, even at concentrations above MIC-2. Our results show the effectiveness of LBs in controlling the growth and biofilm formation of M. furfur clinical strains and highlight the potential of these agents to compose new formulations for the treatment of these fungi.
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http://dx.doi.org/10.1093/mmy/myab051DOI Listing
August 2021

Dynamics of bacterial and archaeal communities along the composting of tannery sludge.

Environ Sci Pollut Res Int 2021 Jul 24. Epub 2021 Jul 24.

Cellular and Molecular Laboratory, Center for Nuclear Energy in Agriculture, University of Sao Paulo, Piracicaba, SP, Brazil.

The process of composting has been proposed as a biological alternative to improve the quality of tannery sludge (TS) by the action of microbial communities. However, there is limited knowledge about the dynamic of these microbial communities during the composting process. This study assessed the responses of bacterial and archaeal communities during TS composting using the 16S rRNA sequencing. The composting process occurred within 90 days, and samples of compost were collected on day 7 (d7; mesophilic stage), 30 (d30; thermophilic stage), 60 (d60; cooling stage), and 90 (d90; maturation stage). The results showed a succession of microbial phyla during the composting with enrichment of Synergistetes, WS1, and Euryarchaeota at the mesophilic stage, while at the thermophilic stage, there was an enrichment of Hydrogenedentes, WPS-2, Chloroflexi, and Deinococcus-Thermus. At the cooling stage, there was an enrichment of Kiritimatiellaeota, and at the maturation stage, there was an enrichment of Entotheonellaeota, Dadabacteria, Nitrospirae, Dependiatiae, and Fibrobacteres. When analyzing the drivers influencing microbial communities, Cr and pH presented more negative correlations with general phyla. In contrast, S, C, K, temperature, and N presented more positive correlations, while Ni, Cd, and P showed fewer correlations. According to niche occupancy, we observed a decreased proportion of generalists with a consequently increased proportion of specialists following the composting process. This study showed that different stages of the composting present a specific microbial community structure and dynamics, which are related to some specific composting characteristics.
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http://dx.doi.org/10.1007/s11356-021-15585-9DOI Listing
July 2021

Microbial co-occurrence network and its key microorganisms in soil with permanent application of composted tannery sludge.

Sci Total Environ 2021 Oct 23;789:147945. Epub 2021 May 23.

Department of Agricultural Engineering and Soil Science, Federal University of Piauí, Brazil. Electronic address:

Soil microbial communities act on important environmental processes, being sensitive to the application of wastes, mainly those potential contaminants, such as tannery sludge. Due to the microbiome complexity, graph-theoretical approaches have been applied to represent model microbial communities interactions and identify important taxa, mainly in contaminated soils. Herein, we performed network and statistical analyses into microbial 16S rRNA gene sequencing data from soil samples with the application of different levels of composted tannery sludge (CTS) to assess the most connected nodes and the nodes that act as bridges to identify key microbes within each community. The network analysis revealed hubs belonging to Proteobacteria in soil with lower CTS rates, while active degraders of recalcitrant and pollutant chemical hubs belonging to Proteobacteria and Actinobacteria were found in soils under the highest CTS rates. The majority of classified connectors belonged to Actinobacteria, but similarly to hubs taxa, they shifted from metabolic functional profile to taxa with abilities to degrade toxic compounds, revealing a soil perturbation with the CTS application on community organization, which also impacted the community modularity. Members of Actinobacteria and Acidobacteria were identified as both hub and connector suggesting their role as keystone groups. Thus, these results offered us interesting insights about crucial taxa, their response to environmental alterations, and possible implications for the ecosystem.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147945DOI Listing
October 2021

Evaluation of metal contamination in mangrove ecosystems near oil refining areas using chemometric tools and geochemical indexes.

Mar Pollut Bull 2021 May 23;166:112179. Epub 2021 Feb 23.

Pós-Graduação em Geoquímica: Petróleo e Meio Ambiente (POSPETRO), Instituto de Geociências, Universidade Federal da Bahia (UFBA), Rua Barão de Jeremoabo, s/n, 40170-290 Salvador, Bahia, Brazil.

The northern and northeastern portion of the Todos os Santos Bay (TSB) is known for the presence of an oil refinery in addition to the development of other activities with significant potential for impact on the environment. 30 samples of superficial mangrove sediment were collected in two different locations: on the banks of the São Paulo River near the Landulpho Alves Mataripe Refinery (RLAM) and at Caboto Beach, a place that was once a control point in studies of metal pollution. After the determination of potentially toxic elements (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, Zn), the quality of the sediment was evaluated using the concentrations of these elements associated with geochemical parameters (TOC, P, S, and granulometry). In this way, the pollution indexes (EF, I, P) were calculated in addition to the comparison with the guide values for the sediment quality (TEL, PEL, ERL, ERM). Among the elements analyzed, Cu also showed levels (92.71-97.54 mg kg) very close to PEL (108 mg kg). At 13 sampling points, Cr concentrations were higher (56.16-66.01 mg kg) than TEL (52.3 mg kg). Ba showed significant concentrations in 6 samples collected on the São Paulo River, a region close to the oil refining area. The enrichment factor (EF) showed that most elements did not show enrichment, except for Zn. Through Igeo there was a tendency towards serious pollution of Ba, Cu, and Zn; moderately polluted by Cr. Principal component analysis (PCA) and Spearman's classification showed a correlation greater than 70% between the variables. According to Nemerow Synthetic Pollution (P), both areas are polluted by Al, Ba, Cr, Cu, Fe, Mn, Ni, Ti, V, and Zn.
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http://dx.doi.org/10.1016/j.marpolbul.2021.112179DOI Listing
May 2021

Distinct bacterial community structure and composition along different cowpea producing ecoregions in Northeastern Brazil.

Sci Rep 2021 01 12;11(1):831. Epub 2021 Jan 12.

Soil Quality Lab, Agricultural Science Center, Federal University of Piauí, Teresina, PI, Brazil.

Soil microbial communities represent the largest biodiversity on Earth, holding an important role in promoting plant growth and productivity. However, the knowledge about how soil factors modulate the bacteria community structure and distribution in tropical regions remain poorly understood, mainly in different cowpea producing ecoregions belonging to Northeastern Brazil. This study addressed the bacterial community along three different ecoregions (Mata, Sertão, and Agreste) through the16S rRNA gene sequencing. The results showed that soil factors, such as Al, sand, Na, cation exchange excel, and total organic C, influenced the bacterial community and could be a predictor of the distinct performance of cowpea production. Also, the bacterial community changed between different ecoregions, and some keystone groups related to plant-growth promotion, such as Bradyrhizobium, Bacillales, Rhizobiales, and Solibacillus, were correlated to cowpea yield, so revealing that the soil microbiome has a primordial role in plant productivity. Here, we provide evidence that bacterial groups related to nutrient cycling can help us to increase cowpea efficiency and we suggest that a better microbiome knowledge can contribute to improving the agricultural performance.
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http://dx.doi.org/10.1038/s41598-020-80840-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7804402PMC
January 2021

Chitosan enhances the antimicrobial photodynamic inactivation mediated by Photoditazine® against Streptococcus mutans.

Photodiagnosis Photodyn Ther 2020 Dec 19;32:102001. Epub 2020 Sep 19.

Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, São Paulo State University/UNESP, São José dos Campos, SP, Brazil. Electronic address:

Chitosan (CS), a biopolymer with intrinsic antimicrobial activity, can increase antimicrobial photodynamic inactivation (aPDI). The aim of this study was to evaluate the capacity of CS to potentiate the efficacy of Photoditazine® (PDZ)-mediated aPDI of the cariogenic bacterium Streptococcus mutans. CS effectively augmented the effects of aPDI, with reductions of approximately 4.5 logs in both planktonic and biofilm states. The combined treatment was also capable of reducing the number of S. mutans cells and amount of extracellular matrix in biofilms formed on enamel surfaces, which were characterized using scanning electron microscopy analysis. Furthermore, CS increased the absorption of PDZ by S. mutans cells. The combination of CS with PDZ-mediated aPDI is hence a promising antimicrobial approach against S. mutans and may be useful to control dental caries.
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http://dx.doi.org/10.1016/j.pdpdt.2020.102001DOI Listing
December 2020

Proposal for a microcosm biofilm model for the study of vulvovaginal candidiasis.

Biofouling 2020 05 3;36(5):610-620. Epub 2020 Jul 3.

Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil.

This study proposes a microcosm biofilm (MiB) model for the study of vulvovaginal candidiasis (VVC). Different conditions that mimic the vaginal environment were tested for MiB formation. The best growth conditions were obtained with samples incubated in vaginal fluid simulator medium pH 4.5 at 35 °C under a microaerophilic atmosphere. MiBs were evaluated for growth kinetics, fluconazole susceptibility and morphology. Samples containing high numbers of bacteria were analyzed for metagenomics. At 48 h, MiBs presented a higher cell density (CFU ml), a higher biomass and tolerance to fluconazole than their corresponding monospecies biofilms. Morphological analysis of MiBs revealed blastoconidia preferentially adhered to epithelial cells. Abundant spp. were detected in two clinical samples; their MiBs showed a lower biomass and a higher fluconazole susceptibility. The proposed model proved to be a useful tool for the study of the complex microbial relationship in the vaginal environment, and may help to find new strategies for VVC control.
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http://dx.doi.org/10.1080/08927014.2020.1785435DOI Listing
May 2020

Dynamics of archaeal community in soil with application of composted tannery sludge.

Sci Rep 2019 05 14;9(1):7347. Epub 2019 May 14.

Federal University of Piauí, Department of Agricultural Engineering and Soil Science, Teresina, 64049-550, Brazil.

Application of composted tannery sludge (CTS) could promote a shift in the structure of soil microbial communities. Although the effect of CTS on bacterial community has been studied, it is unclear how the composition and diversity of archaeal community respond to CTS amendment and which environmental factors drive the community over time. Here, we hypothesize that the Archaea structure and composition respond to CTS amendment over the time. CTS had been previously applied annually along 6 years and this assessment occurred for 180 days following the application in the 7 year by using different rates (0, 2.5, 5, 10 and 20 ton ha). We used amplicon 16S rRNA sequencing to assess the changes in the structure of the archaeal community. Thaumarchaeota and Euryarchaeota were the most abundant phyla found in soils with application of CTS, with Thaumarchaeota dominating the sequences in all samples with relative abundances of >98%. We observed a decreasing trend on the archaeal diversity over the time with increasing CTS application rate, together with an increase in the community similarity. The redundancy analyses (RDA) explained 43% of the total variation in operational taxonomic units and identified Na, pH, Cr and P as the main drivers of the archaeal community over time after application of highest CTS rates. CTS application changes the structure of Archaea community, with significant increase of Thaumarchaeota and Aenigmarchaeota groups, which can be further explored for its biotechnological use in contaminated soils.
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http://dx.doi.org/10.1038/s41598-019-43478-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6517401PMC
May 2019

Effects of carbon source on the formation, stability, bioactivity and biodiversity of the aerobic granule sludge.

Bioresour Technol 2019 Apr 19;278:195-204. Epub 2019 Jan 19.

Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil. Electronic address:

Three aerobic granular sludge systems were operated as sequencing batch reactors (SBR) with acetate, ethanol and glucose as carbon source. The SBR cycle was 6 h, with an anaerobic phase followed by an aerobic phase. The acetate granules (>1.5 mm) had the greatest microbial diversity and better results in terms of removal efficiency for carbon and nutrients (TN ≈ 72% and TP ≈ 42%) and also in the resistance tests. However, partial disintegration was observed. On the other hand, when ethanol was the substrate, the granules were stable, good nitrogen removal was achieved (TN ≈ 53%), but phosphorus removal was not favored (TP ≈ 31%). Glucose presented the lowest efficiency values for nitrogen (TN ≈ 44%) and phosphorous removal (TP ≈ 21%), and the granules formed (<1 mm) had the lowest microbial diversity. Therefore, the carbon source had a high impact on the characteristics of the granules.
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http://dx.doi.org/10.1016/j.biortech.2019.01.071DOI Listing
April 2019

Purification and characterization of a biosurfactant produced by Bacillus subtilis in cashew apple juice and its application in the remediation of oil-contaminated soil.

Colloids Surf B Biointerfaces 2019 Mar 27;175:256-263. Epub 2018 Nov 27.

Department of Chemical Engineering, Universidade Federal do Ceará, Brazil.

The ability of some microorganisms to use clarified cashew apple juice as carbon and energy source for biosurfactant production was assessed under strict controlled conditions. Twelve strains of Bacillus were isolated and evaluated regarding their biosurfactant production capabilities. The biosurfactant obtained with these selected strains showed the capacity of decreasing the surface tension of water from 72.0 to 31.8 mN.m and the interfacial tension of n-hexadecane to 27.2 mN.m, with a critical micelle concentration of 12.5 mg.L. Not only did the biosurfactant present excellent stability to pH, temperature and salinity, it also showed emulsifying properties in different hydrocarbons. The behavior of the phase diagrams showed the potential of the produced biosurfactant to obtain relatively-stable emulsions for up to 96 h, which allows for its application in several areas. The semi-purified biosurfactant did not show toxicity against Lactuca sativa (lettuce) or Artemia salina (microcrustacean), presenting an LC of 612.27 μ mL. The surfactant was characterized as being a cyclic lipopeptide with molecular structure similar to that of surfactin. Furthermore, through the employment of the surfactant produced, the remediation effect in oil-contaminated soil could be significantly improved.
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http://dx.doi.org/10.1016/j.colsurfb.2018.11.062DOI Listing
March 2019

Protist species richness and soil microbiome complexity increase towards climax vegetation in the Brazilian Cerrado.

Commun Biol 2018 6;1:135. Epub 2018 Sep 6.

Department of Terrestrial Ecology, Netherlands Institute of Ecology NIOO-KNAW, 6708 PB, Wageningen, The Netherlands.

Biodiversity underlies ecosystem functioning. While aboveground biodiversity is often well studied, the belowground microbiome, in particular protists, remains largely unknown. Indeed, holistic insights into soil microbiome structures in natural soils, especially in hyperdiverse biomes such as the Brazilian Cerrado, remain unexplored. Here, we study the soil microbiome across four major vegetation zones of the Cerrado, ranging from grass-dominated to tree-dominated vegetation with a focus on protists. We show that protist taxon richness increases towards the tree-dominated climax vegetation. Early successional habitats consisting of primary grass vegetation host most potential plant pathogens and least animal parasites. Using network analyses combining protist with prokaryotic and fungal sequences, we show that microbiome complexity increases towards climax vegetation. Together, this suggests that protists are key microbiome components and that vegetation succession towards climax vegetation is stimulated by higher loads of animal and plant pathogens. At the same time, an increase in microbiome complexity towards climax vegetation might enhance system stability.
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http://dx.doi.org/10.1038/s42003-018-0129-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6127325PMC
September 2018

Less abundant bacterial groups are more affected than the most abundant groups in composted tannery sludge-treated soil.

Sci Rep 2018 08 6;8(1):11755. Epub 2018 Aug 6.

Federal University of Piauí, Department of Agricultural Engineering and Soil Science, Teresina, 64049-550, Brazil.

The application of composted tannery sludge (CTS) has promoted shifts in soil chemical properties and, therefore, can affect the soil bacterial community. This study assessed the effect of the CTS on the soil bacterial community over time. The CTS was applied at five rates (0, 2.5, 5, 10 and 20 t/ha), and the bacterial community was evaluated for 180 days. The principal curve response (PRC) analysis showed that the most abundant phyla were not influenced by the CTS rates over time, while the analysis of the bacterial community showed that some of the less abundant phyla were influenced by the CTS rates. Similarly, the PRC analysis for the bacterial classes showed the significant effect of the CTS rates. The redundancy analyses for the bacterial phyla and classes showed the relationship between the significant chemical properties and the bacterial community of the soil after the CTS amendment over time. Therefore, there was a shift in the bacterial community over time with the application of the composted tannery sludge. Our study has shown that the less abundant bacterial groups were more influenced by the CTS than the most abundant bacterial groups and that these bacterial groups were driven by soil chemical properties, primarily chromium (Cr) and the soil pH.
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http://dx.doi.org/10.1038/s41598-018-30292-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6079073PMC
August 2018

Inhibitory effect of a lipopeptide biosurfactant produced by Bacillus subtilis on planktonic and sessile cells of Trichosporon spp.

Biofouling 2018 03 21;34(3):309-319. Epub 2018 Mar 21.

a Department of Pathology and Legal Medicine , Federal University of Ceará , Fortaleza , Brazil.

The present study aimed to investigate the inhibitory effect of a bacterial biosurfactant (TIM96) on clinical strains of Trichosporon. Additionally, the effect of TIM96 on the ergosterol content, cell membrane integrity, and the hydrophobicity of planktonic cells was assessed. The inhibitory activity of TIM96 against Trichosporon biofilms was evaluated by analyzing metabolic activity, biomass and morphology. MIC values ranged from 78.125 to 312.5 μg ml for TIM96; time-kill curves revealed that the decline in the number of fungal cells started after incubation for 6 h with TIM96 at both MIC and 2×MIC. The biosurfactant reduced the cellular ergosterol content and altered the membrane permeability and the surface hydrophobicity of planktonic cells. Incubation at 10×MIC TIM96 reduced cell adhesion by up to 96.89%, thus interfering with biofilm formation. This concentration also caused up to a 99.2% reduction in the metabolic activity of mature biofilms. The results indicate potential perspectives for the development of new antifungal strategies.
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http://dx.doi.org/10.1080/08927014.2018.1437617DOI Listing
March 2018

Archaea diversity in vegetation gradients from the Brazilian Cerrado.

Braz J Microbiol 2018 Jul - Sep;49(3):522-528. Epub 2018 Feb 11.

Federal University of Ceara, Laboratório de Ecologia Microbiana e Biotecnologia, Fortaleza, CE, Brazil.

We used 16S rRNA sequencing to assess the archaeal communities across a gradient of Cerrado. The archaeal communities differed across the gradient. Crenarcheota was the most abundant phyla, with Nitrosphaerales and NRPJ as the predominant classes. Euryachaeota was also found across the Cerrado gradient, including the classes Metanocellales and Methanomassiliicoccaceae.
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http://dx.doi.org/10.1016/j.bjm.2017.08.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6066726PMC
October 2018

Fungal diversity in soils across a gradient of preserved Brazilian Cerrado.

J Microbiol 2017 Apr 27;55(4):273-279. Epub 2017 Jan 27.

Microbial Ecology and Biotechnology Lab., Federal University of Ceara, Fortaleza, CE, Brazil.

The preserved Cerrado from Northeastern Brazil presents different physicochemical properties and plant diversity, which can influence the fungal communities. Therefore, we evaluated the fungal diversity in preserved sites, at Sete Cidades National Park, across a gradient of vegetation that included Campo graminoide, Cerrado stricto sensu, Cerradao, and Floresta decidual. Of all of the operational taxonomic units (OTUs) obtained, the Floresta decidual presented the highest richness. Ascomycota were the most abundant phylum (45%), followed by Basidiomycota (32%). Basal fungi and other phyla accounted for 23% of the total dataset. Agaricomycetes, Eurotiomycetes, Lecanoromycetes, Basidiobolus, Dothideomycetes, and Taphrinomycetes were the most abundant classes of fungi found across the gradient of Cerrado vegetation. In conclusion, our study suggests that the Brazilian Cerrado from Sete Cidades National Park presents a high fungal diversity and includes sources of new fungal species for biotechnological purposes.
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http://dx.doi.org/10.1007/s12275-017-6350-6DOI Listing
April 2017

Distinct bacterial communities across a gradient of vegetation from a preserved Brazilian Cerrado.

Antonie Van Leeuwenhoek 2017 Apr 6;110(4):457-469. Epub 2017 Jan 6.

Laboratório de Ecologia Microbiana e Biotecnologia, Federal University of Ceara, Fortaleza, CE, Brazil.

The Cerrado biome in the Sete Cidades National Park, an Ecological Reserve in Northeastern Brazil, has conserved its native biodiversity and presents a variety of plants found in other savannas in Brazil. Despite this finding the soil microbial diversity and community structure are poorly understood. Therefore, we described soil bacterial diversity and distribution along a savanna vegetation gradient taking into account the prevailing environmental factors. The bacterial composition was retrieved by sequencing a fragment of the 16S ribosomal RNA gene. The bacterial operational taxonomic units (OTUs) were assigned to 37 different phyla, 96 classes, and 83 genera. At the phylum level, a core comprised by Proteobacteria, Acidobacteria, Actinobacteria, Firmicutes, Verrucomicrobia and Planctomycetes, was detected in all areas of Cerrado. 'Cerrado stricto sensu' and 'Cerradao' share more similarities between edaphic properties and vegetation and also present more similar bacterial communities, while 'Floresta decidual' and 'Campo graminoide' show the largest environmental differences and also more distinct bacterial communities. Proteobacteria (26%), Acidobacteria (21%) and Actinobacteria (21%) were the most abundant phyla within the four areas. All the samples present similar bacteria richness (alpha diversity) and the observed differences among them (beta diversity) were more related to the abundance of specific taxon OTUs compared to their presence or absence. Total organic C, N and P are the main abiotic factors structuring the bacterial communities. In summary, our findings show the bacterial community structure was clearly different across the Cerrado gradient, but that these environments share a bacterial phylum-core comprising Proteobacteria, Acidobacteria, Actinobacteria, Verrucomicrobia and Planctomycetes with other Brazilian savannas.
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http://dx.doi.org/10.1007/s10482-016-0815-1DOI Listing
April 2017

Frog Foam Nest Protein Diversity and Synthesis.

J Exp Zool A Ecol Genet Physiol 2016 Aug 27;325(7):425-33. Epub 2016 Jul 27.

Departamento de Biologia, Universidade Federal do Ceará, Av. Humberto Monte, Fortaleza, Ceará, Brazil.

Some amphibian species have developed a breeding strategy in which they deposit their eggs in stable foam nests to protect their eggs and larvae. The frog foam nests are rich in proteins (ranaspumin), especially surfactant proteins, involved in the production of the foam nest. Despite the ecological importance of the foam nests for evolution and species conservation, the biochemical composition, the long-term stability and even the origin of the components are still not completely understood. Recently we showed that Lv-RSN-1, a 23.5-kDa surfactant protein isolated from the nest of the frog Leptodacylus vastus, presents a structural conformation distinct from any protein structures yet reported. So, in the current study we aimed to reveal the protein composition of the foam nest of L. vastus and further characterize the Lv-RSN-1. Proteomic analysis showed the foam nest contains more than 100 of proteins, and that Lv-RSN-1 comprises 45% of the total proteins, suggesting a key role in the nest construction and stability. We demonstrated by Western blotting that Lv-RSN-1 is mainly produced only by the female in the pars convoluta dilata, which highlights the importance of the female preservation for conservation of species that depend on the production of foam nests in the early stages of development. Overall, our results showed the foam nest of L. vastus is composed of a great diversity of proteins and that besides Lv-RSN-1, the main protein in the foam, other proteins must have a coadjuvant role in building and stability of the nest.
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http://dx.doi.org/10.1002/jez.2027DOI Listing
August 2016

Metagenomic analysis of sediments under seaports influence in the Equatorial Atlantic Ocean.

Sci Total Environ 2016 07 17;557-558:888-900. Epub 2016 Apr 17.

Instituto de Ciências do Mar, Av. Abolição, 3207, 60170-151 Fortaleza, Ceará, Brazil; Laboratório de Ecologia Microbiana e Biotecnologia, Departamento de Biologia, Bloco 909, Centro de Ciências, Campus do Pici, Universidade Federal do Ceará, Av. Humberto Monte, 2775, 60440-554 Fortaleza, Ceará, Brazil. Electronic address:

Maritime ports are anthropogenic interventions capable of causing serious alterations in coastal ecosystems. In this study, we examined the benthic microbial diversity and community structure under the influence of two maritime ports, Mucuripe (MUC) and Pecém (PEC), at Equatorial Atlantic Ocean in Northeast Brazil. Those seaports differ in architecture, time of functioning, cargo handling and contamination. The microbiomes from MUC and PEC were also compared in silico to 11 other globally distributed marine microbiomes. The comparative analysis of operational taxonomic units (OTUs) retrieved by PCR-DGGE showed that MUC presents greater richness and β diversity of Bacteria and Archaea than PEC. In line with these results, metagenomic analysis showed that MUC and PEC benthic microbial communities share the main common bacterial phyla found in coastal environments, although can be distinguish by greater abundance of Cyanobacteria in MUC and Deltaproteobacteria in PEC. Both ports differed in Archaea composition, being PEC port sediments dominated by Thaumarchaeota. The microbiomes showed little divergence in their potential metabolic pathways, although shifts on the microbial taxonomic signatures involved in nitrogen and sulphur metabolic pathways were observed. The comparative analysis of different benthic marine metagenomes from Brazil, Australia and Mexico grouped them by the geographic location rather than by the type of ecosystem, although at phylum level seaport sediments share a core microbiome constituted by Proteobacteria, Cyanobacteria, Actinobacteria, Tenericuteres, Firmicutes, Bacteriodetes and Euryarchaeota. Our results suggest that multiple physical and chemical factors acting on sediments as a result of at least 60years of port operation play a role in shaping the benthic microbial communities at taxonomic level, but not at functional level.
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http://dx.doi.org/10.1016/j.scitotenv.2016.03.141DOI Listing
July 2016

Interaction of antimicrobial peptide Plantaricin149a and four analogs with lipid bilayers and bacterial membranes.

Braz J Microbiol 2013 Dec 10;44(4):1291-8. Epub 2014 Mar 10.

Grupo de Biofísica Molecular "Sérgio Mascarenhas", Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.

The amidated analog of Plantaricin149, an antimicrobial peptide from Lactobacillus plantarum NRIC 149, directly interacts with negatively charged liposomes and bacterial membranes, leading to their lysis. In this study, four Pln149-analogs were synthesized with different hydrophobic groups at their N-terminus with the goal of evaluating the effect of the modifications at this region in the peptide's antimicrobial properties. The interaction of these peptides with membrane models, surface activity, their hemolytic effect on red blood cells, and antibacterial activity against microorganisms were evaluated. The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5%) until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes. The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 μM and 155 μM to Plantaricin149a, respectively) but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs. This difference was confirmed by a reduction in leakage action for the analogs. The lytic activity of Plantaricin149a is suggested to be a result of the peptide-lipid interactions from the amphipathic helix and the hydrophobic residues at the N-terminus of the antimicrobial peptide.
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http://dx.doi.org/10.1590/S1517-83822014005000007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3958201PMC
December 2013

Unique crystal structure of a novel surfactant protein from the foam nest of the frog Leptodactylus vastus.

Chembiochem 2014 Feb 17;15(3):393-8. Epub 2014 Jan 17.

Lab. de Ecologia Microbiana e Biotecnologia-LEMBiotech, Departamento de Biologia, Universidade Federal do Ceará, Av. Humberto Monte 2977, Campus do Pici, Bloco 909, Fortaleza, CE, 60455-000 (Brazil).

Breeding by releasing eggs into stable biofoams ("foam nests") is a peculiar reproduction mode within anurans, fish, and tunicates; not much is known regarding the biochemistry or molecular mechanisms involved. Lv-ranaspumin (Lv-RSN-1) is the predominant protein from the foam nest of the frog Leptodactylus vastus. This protein shows natural surfactant activity, which is assumed to be crucial for stabilizing foam nests. We elucidated the amino acid sequence of Lv-RSN-1 by de novo sequencing with mass-spectrometry and determined the high-resolution X-ray structure of the protein. It has a unique fold mainly composed of a bundle of 11 α-helices and two small antiparallel β-strands. Lv-RSN-1 has a surface rich in hydrophilic residues and a lipophilic cavity in the region of the antiparallel β-sheet. It possesses intrinsic surface-active properties, reducing the surface tension of water from 73 to 61 mN m(-1) (15 μg mL(-1)). Lv-RSN-1 belongs to a new class of surfactants proteins for which little has been reported regarding structure or function.
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http://dx.doi.org/10.1002/cbic.201300726DOI Listing
February 2014

Antibacterial, antioxidant, and anticholinesterase activities of plant seed extracts from Brazilian semiarid region.

Biomed Res Int 2013 10;2013:510736. Epub 2013 Dec 10.

Departamento de Biologia, Universidade Federal do Ceará, Campus do Pici, 60451-970 Fortaleza, CE, Brazil.

The antimicrobial, antioxidant, and anticholinesterase activities of ethanolic seed extracts of twenty-one plant species from Brazilian semiarid region were investigated. The extracts were tested for antimicrobial activity against six bacteria strains and three yeasts. Six extracts presented activity against the Gram (-) organism Salmonella choleraesuis and the Gram (+) organisms Staphylococcus aureus and Bacillus subtilis. The MIC values ranged from 4.96 to 37.32 mg/mL. The Triplaris gardneriana extract presented activity against the three species, with MIC values 18.8, 13.76, and 11.15 mg/mL, respectively. Five extracts presented antioxidant activity, with EC50 values ranging from 69.73 μ g/mL (T. gardneriana) to 487.51 μ g/mL (Licania rigida). For the anticholinesterase activity, eleven extracts were capable of inhibiting the enzyme activity. From those, T. gardneriana, Parkia platycephala and Connarus detersus presented the best activities, with inhibition values of 76.7, 71.5, and 91.9%, respectively. The extracts that presented antimicrobial activity were tested for hemolytic assay against human A, B, and O blood types and rabbit blood. From those, only the Myracrodruon urundeuva extract presented activity (about 20% of hemolysis at the lowest tested concentration, 1.9 µg/mL). Infrared spectroscopy of six representative extracts attested the presence of tannins, polyphenols, and flavonoids, which was confirmed by a qualitative phytochemical assay.
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http://dx.doi.org/10.1155/2013/510736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3872380PMC
June 2014

An innovative bioremediation strategy using a bacterial consortium entrapped in chitosan beads.

J Environ Manage 2013 Sep 6;127:10-7. Epub 2013 May 6.

Laboratório de Ecologia Microbiana e Biotecnologia (LEM Biotech), Departamento de Biologia, Universidade Federal do Ceará, Av. Humberto Monte, 2977, Campus do Pici, Bloco 909, 60455-000 Fortaleza, Ceará, Brazil.

This aim of this work was to develop a bioremediation strategy for oil-contaminated mangrove sediments using chitosan beads containing an immobilised hydrocarbonoclastic bacterial consortium. The consortium composed of 17 isolates was obtained from an enrichment culture. The isolates were identified by 16S rDNA sequencing, which revealed 12 different genera. Thirteen isolates showed resistance to chitosan and were thus able to be trapped in chitosan beads for microcosm evaluation. The data revealed that entrapped consortium grew in the microcosms until day 15, which is when the beads disintegrated and released their biomass into the sediments. Bacterial bioaugmentation within the sediments was confirmed by cell counts; additionally, the dynamics of the bacterial populations were analysed through denaturing gradient gel electrophoresis. The chitosan showed a prebiotic effect on the autochthonous bacterial communities. Therefore, chitosan beads containing selected immobilised bacteria attain two bioremediation purposes, bioaugmentation and biostimulation, and thus represent an emergent approach.
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http://dx.doi.org/10.1016/j.jenvman.2013.04.014DOI Listing
September 2013

Crystallization and preliminary X-ray diffraction of the surfactant protein Lv-ranaspumin from the frog Leptodactylus vastus.

Acta Crystallogr Sect F Struct Biol Cryst Commun 2012 Mar 23;68(Pt 3):321-3. Epub 2012 Feb 23.

Laboratório de Ecologia Microbiana e Biotecnologia (LEMBiotech), Departamento de Biologia, Universidade Federal do Ceará, Avenida Humberto Monte 2977, Campus do Pici, Bloco 909, 60455-000 Fortaleza-CE, Brazil.

Lv-ranaspumin is a natural surfactant protein with a molecular mass of 23.5 kDa which was isolated from the foam nest of the frog Leptodactylus vastus. Only a partial amino-acid sequence is available for this protein and it shows it to be distinct from any protein sequence reported to date. The protein was purified from the natural source by ion-exchange and size-exclusion chromatography and was crystallized by sitting-drop vapour diffusion using the PEG/Ion screen at 293 K. A complete data set was collected to 3.5 Å resolution. The crystal belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 51.96, b = 89.99, c = 106.00 Å. Assuming the presence of two molecules in the asymmetric unit, the solvent content was estimated to be 54%.
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http://dx.doi.org/10.1107/S1744309112002679DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3310541PMC
March 2012

Novel surfactant proteins are involved in the structure and stability of foam nests from the frog Leptodactylus vastus.

J Exp Biol 2008 Aug;211(Pt 16):2707-11

Departamento de Biologia, Universidade Federal do Ceará, Av. Humberto Monte 2775 Campus Pici, Bloco 909, Fortaleza, Brazil.

Many amphibians lay their eggs in foam nests, which allow the eggs to be deposited out of the water. Analysis of some of these foam nests has revealed that they are a rich source of proteins with unusual primary structures and remarkable surfactant activity, named ranaspumins. The aim of this work was to study the foam nests of the frog Leptodactylus vastus in order to obtain information regarding their composition and function and to improve the understanding of ranaspumins, which are probably a novel class of surfactant proteins. Analyses of the foam fluid composition showed proteins and carbohydrates that presumably are responsible for providing nutrients for the developing tadpoles. Investigation of the function of foam fluid in chemical defence revealed no significant biological activity that could be associated with recognized defence compounds. However, foam fluid presented UV absorbance, suggesting a role in protection against sun damage, which is considered to be one of the possible causes of recently reported amphibian population declines. The foam nests do not prevent the colonization of microorganisms, such as the observed bacterial community of predominantly Gram-positive bacilli. L. vastus foam fluid shows a strong surfactant activity that was associated with their proteins and this activity seems to be due mainly to a protein named Lv-ranaspumin. This protein was isolated by ion-exchange chromatography and found to be a 20 kDa monomeric molecule with the following N-terminal sequence: FLEGFLVPKVVPGPTAALLKKALDD. This protein did not show any match to known proteins or structures, which suggests that it belongs to a new class of surfactant protein.
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http://dx.doi.org/10.1242/jeb.019315DOI Listing
August 2008

Isolation and characterization of phenol-degrading yeasts from an oil refinery wastewater in Brazil.

Mycopathologia 2007 Oct 3;164(4):183-8. Epub 2007 Aug 3.

Laboratory of Microbiology and Immunology, Department of Biology, Sciences Center, Federal University of Ceará, Campus do Pici, Bloco 909, Fortaleza, CE, CEP, Brazil.

This study investigated the aerobic degradation of phenol by yeast strains isolated from an oil refinery wastewater from the Northeast of Brazil. The samples displayed low fungal diversity, as only yeast colonies were detected on Sabouraud dextrose agar containing chloramphenicol 0.05% (w/v). Among the isolates, three yeast strains were selected to be evaluated for their potential for degrading high phenol concentrations. These species were identified through morphological and biochemical characteristics as Candida tropicalis, C. rugosa, and Pichia membranaefaciens. Although the strains were able to degrade the phenol concentration present in the wastewater, which was 7 mg l(-1), only C. tropicalis was capable of growing at high concentrations of phenol such as 500 mg l(-1 )and 1,000 mg l(-1) in a mineral medium containing this pollutant as the only carbon source. C. rugosa and P. membranaefaciens were inhibited in the presence of 500 mg l(-1) of phenol. However, a longer incubation time was needed for C. tropicalis strain to degrade 1,000 mg l(-1) of phenol compared to the time required to degrade 500 mg l(-1). Moreover, the strain released a significant amount of polysaccharide biosurfactant in the medium probably to minimize the toxic effect of the high phenol concentration. When challenged with 1,500 and 2,000 mg l(-1 )of phenol, C. tropicalis was unable to grow at the tested conditions. The results indicate that this strain of C. tropicalis can be considered both a good phenol-degrader and biosurfactant-producer. Application of this strain might be useful in bioremediation activities or treatment of phenol-polluted wastewater.
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http://dx.doi.org/10.1007/s11046-007-9043-6DOI Listing
October 2007

Larvicidal activity of the essential oil from Lippia sidoides Cham. Against Aedes aegypti linn.

Mem Inst Oswaldo Cruz 2003 Jun 18;98(4):569-71. Epub 2003 Aug 18.

Departamento de Biologia, Universidade Federal do Ceará, Campus do Pici 60455-900 Fortaleza, DE, Brasil.

The aim of this work was to study the larvicidal activity of Lippia sidoides essential oil against Aedes aegypti larvae. The essential oil and its hydrolate (saturated solution of essential oil in water) were obtained by vapor extraction and their chemical composition determined by GL-chromatography coupled to mass spectroscopy. Bioassays were run with the essential oil, pure and diluted hydrolate and with their main constituents thymol and carvacrol. The results obtained showed that L. sidoides essential oil and its hydrolate have larvicidal action against the mosquito A. aegypti, causing an almost instantaneous mortality. Thymol, an alkylated phenol derivative and one of the major components of L. sidoides essential oil, was identified as the active principle responsible for the larvicidal action, causing 100% larval mortality at the lowest tested concentration of 0.017% (w/v). These results suggest that the essential oil of L. sidoides is promising as larvicide against A. aegypti and could be useful in the search of newer, more selective, and biodegradable larvicidal natural compounds to be used in official combat programs and at home.
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http://dx.doi.org/10.1590/s0074-02762003000400027DOI Listing
June 2003
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