RESUMO

Andiroba (Carapa guianensis Aubl) is an Amazonian plant whose oil has been widely used in traditional medicine for various purposes, including anti-inflammation. Research reports indicate that the oil can confer antitumor activity due to the presence of fatty acids, which can directly influence cell death mechanisms. Thus, andiroba oil (AO) has gained interest for its potential to be used in antineoplastic therapies. Here, we report an in vitro analysis of the cytotoxic and mutagenic potential of AO in the gastric cancer cell line, ACP02. Cell survival was assessed by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, differential staining with ethidium bromide and acridine orange assessed apoptosis-necrosis, and mutagenesis was assessed by the micronucleus test. The apolar oil was first diluted in 0.1% dimethyl sulfoxide (DMSO) and then further diluted to six concentrations (0.01, 0.1, 1, 10 and 100 µg/mL and 1 mg/mL) in RPMI medium. Controls included RPMI alone (negative control) and 0.1% DMSO diluted in medium (vehicle control). The MTT test showed that AO significantly reduced cell viability (P < .05) only when the highest tested concentration was applied for 48 hours. The apoptosis/necrosis test showed that the highest concentration of AO induced cell death by apoptosis at 24 and 48 hours. There was no statistically significant increase in the frequency of micronuclei. The ability of the AO to decrease the viability of ACP02 cells via apoptosis, without exerting mutagenic effects, suggests that the oil could be useful as an alternative therapeutic agent for primary tumors of stomach cancer.

Assuntos

RESUMO

BACKGROUND: The Neacomys genus is predominantly found in the Amazon region, and belongs to the most diverse tribe of the Sigmodontinae subfamily (Rodentia, Cricetidae, Oryzomyini). The systematics of this genus and questions about its diversity and range have been investigated by morphological, molecular (Cytb and COI sequences) and karyotype analysis (classic cytogenetics and chromosome painting), which have revealed candidate species and new distribution areas. Here we analyzed four species of Neacomys by chromosome painting with Hylaeamys megacephalus (HME) whole-chromosome probes, and compared the results with two previously studied Neacomys species and with other taxa from Oryzomyini and Akodontini tribes that have been hybridized with HME probes. Maximum Parsimony (MP) analyses were performed with the PAUP and T.N.T. software packages, using a non-additive (unordered) multi-state character matrix, based on chromosomal morphology, number and syntenic blocks. We also compared the chromosomal phylogeny obtained in this study with molecular topologies (Cytb and COI) that included eastern Amazonian species of Neacomys, to define the phylogenetic relationships of these taxa. RESULTS: The comparative chromosome painting analysis of the seven karyotypes of the six species of Neacomys shows that their diversity is due to 17 fusion/fission events and one translocation, pericentric inversions in four syntenic blocks, and constitutive heterochromatin (CH) amplification/deletion of six syntenic autosomal blocks plus the X chromosome. The chromosomal phylogeny is consistent with the molecular relationships of species of Neacomys. We describe new karyotypes and expand the distribution area for species from eastern Amazonia and detect complex rearrangements by chromosome painting among the karyotypes. CONCLUSIONS: Our phylogeny reflects the molecular relationships of the Akodontini and Oryzomyini taxa and supports the monophyly of Neacomys. This work presents new insights about the chromosomal evolution of this group, and we conclude that the karyotypic divergence is in accord with phylogenetic relationships.

Assuntos

RESUMO

The conversion of native forest to agriculture is the main cause of microbial biodiversity loss in Amazon soils. In order to better understand this effect, we used metagenomics to investigate microbial patterns and functions in bulk soil and rhizosphere of soybean, in a long-term forest-to-agriculture conversion. Long-term forest-to-agriculture led to microbial homogenization and loss of diversity in both bulk soil and rhizosphere, mainly driven by decreasing aluminum concentration and increased cations saturation in soil, due to liming and fertilization in long-term no-till cropping. Data revealed that long-term no-till cropping culminated in a decrease in Acidobacteria, Actinobacteria and Proteobacteria abundances. However, α- and ß-Proteobacteria abundances were higher in the rhizosphere than in bulk soil, regardless of the time after forest-to-agriculture conversion. Changes in functional potential occurred predominantly in bulk soil, with decreases in functions related to potassium metabolism and virulence, disease and defense, while functions related to nucleic acids metabolism increased. Functions in the soybean rhizosphere remained stable, except for those related to potassium metabolism, which decreased after 20-year no-till cropping. Together, our results show that the soybean root system selects microbial taxa via trade-offs, to maintain functional resilience in the rhizosphere microbiome over time.

Assuntos

RESUMO

Four syntopic species of Soesilarishius Makhan, 2007 are recorded from the Floresta Estadual do Trombetas, Oriximiná, Pará, Brazil. The first is the type species of the genus, S. amrishi Makhan, 2007, of which we redescribe the male and describe the female for the first time. The other three species are new and described herein based on both sexes: S. laticlavus sp. nov., S. trombetas sp. nov. and S. elongatulus sp. nov.

Assuntos

RESUMO

We inventoried the birds from Serra do Aracá region, state of Amazonas. The region encompasses a high diversity of vegetation types, including white sand forests and campinas, terra firme and flooded forests, montane forests and tepuis. We recorded 416 bird taxa in 69 families through captures with mist nets, tape recording of bird voices, and collection of voucher specimens. A large proportion of them (61%) were recorded in a single vegetation type. Qualitative estimates suggest that approximately 580 bird species occur in the region. The avifauna of the Aracá region has a mixed biogeographic composition, with species typical of both margins of the Rio Negro occurring sympatrically. Additionally, species whose distributions are restricted to three areas of endemism for Amazonian birds (Imeri, Guiana and Pantepui) were recorded in the region. Rare landscapes in the Brazilian Amazon are found in the Serra do Aracá region. Additionally, we recorded endemic and rare birds, highlighting the value of the region for conservation. The Serra do Aracá State Park officially protects montane forests, terra firme forests and tepuis. We suggest that the large extension of white sand campinas and igapó forests at the southern portion of Serra do Aracá should be also preserved in order to improve the representation of the rich natural heritage of the region.

Assuntos

RESUMO

We inventoried the birds from Serra do Aracá region, state of Amazonas. The region encompasses a high diversity of vegetation types, including white sand forests and campinas, terra firme and flooded forests, montane forests and tepuis. We recorded 416 bird taxa in 69 families through captures with mist nets, tape recording of bird voices, and collection of voucher specimens. A large proportion of them (61%) were recorded in a single vegetation type. Qualitative estimates suggest that approximately 580 bird species occur in the region. The avifauna of the Aracá region has a mixed biogeographic composition, with species typical of both margins of the Rio Negro occurring sympatrically. Additionally, species whose distributions are restricted to three areas of endemism for Amazonian birds (Imeri, Guiana and Pantepui) were recorded in the region. Rare landscapes in the Brazilian Amazon are found in the Serra do Aracá region. Additionally, we recorded endemic and rare birds, highlighting the value of the region for conservation. The Serra do Aracá State Park officially protects montane forests, terra firme forests and tepuis. We suggest that the large extension of white sand campinas and igapó forests at the southern portion of Serra do Aracá should be also preserved in order to improve the representation of the rich natural heritage of the region.(AU)

Assuntos

RESUMO

This work presents a simple and rapid technique to select fungal strains with the ability to produce laccases. Fifteen strains of Colletotrichum spp. from the Amazon region (isolated from cumarú, puerária, cupuaçu and weed plants), as well as a strain isolated from espinheira santa in the south of Brazil, were found to produce laccases. Laccase activity was assayed using ABTS and DMP as putative substrates. Only Colletotrichum isolates of puero (P2 and P3) did not present activity towards DMP. Isolates D3 (weed plants), M3 (espinheira santa), C2 and C3 (cumarú) were selected, and were compared with the basidiomycete Pleurotus ostreatus used as a reference laccase producer under stationary and submerged culture conditions. Highest laccase activity was detected only in the stationary cultures of Colletotrichum isolate D3 assayed against ABTS (35 U/l) and DMP (8 U/l).

O presente trabalho apresenta uma metodologia simples e rápida para selecionar isolados fúngicos produtores de lacases. Foram avaliados quinze isolados de Colletotrichum da biodiversidade da Amazônia (obtidos de cumarú, puerária, cupuaçu e plantas daninhas), além de um isolado de espinheira santa do sul do país, quanto à produção de lacases. A atividade da enzima foi determinada utilizandose os substratos ABTS e o DMP. Somente os isolados de puerária P2 e P3 não apresentaram atividade sobre o substrato DMP. Os isolados D3 (planta daninha), M3 (espinheira santa), C2 e C3 (cumarú) foram selecionados e comparados quanto à produção de lacases em cultivos líquidos estáticos e agitados, utilizando-se o Pleurotus ostreatus, um basidiomiceto produtor de lacase, como referência. A maior atividade de lacase foi detectada apenas nos cultivos estáticos do isolado D3 (35U/l em ABTS; 8U/l em e DMP).

RESUMO

This work presents a simple and rapid technique to select fungal strains with the ability to produce laccases. Fifteen strains of Colletotrichum spp. from the Amazon region (isolated from cumarú, puerária, cupuaçu and weed plants), as well as a strain isolated from espinheira santa in the south of Brazil, were found to produce laccases. Laccase activity was assayed using ABTS and DMP as putative substrates. Only Colletotrichum isolates of puero (P2 and P3) did not present activity towards DMP. Isolates D3 (weed plants), M3 (espinheira santa), C2 and C3 (cumarú) were selected, and were compared with the basidiomycete Pleurotus ostreatus used as a reference laccase producer under stationary and submerged culture conditions. Highest laccase activity was detected only in the stationary cultures of Colletotrichum isolate D3 assayed against ABTS (35 U/l) and DMP (8 U/l).

O presente trabalho apresenta uma metodologia simples e rápida para selecionar isolados fúngicos produtores de lacases. Foram avaliados quinze isolados de Colletotrichum da biodiversidade da Amazônia (obtidos de cumarú, puerária, cupuaçu e plantas daninhas), além de um isolado de espinheira santa do sul do país, quanto à produção de lacases. A atividade da enzima foi determinada utilizandose os substratos ABTS e o DMP. Somente os isolados de puerária P2 e P3 não apresentaram atividade sobre o substrato DMP. Os isolados D3 (planta daninha), M3 (espinheira santa), C2 e C3 (cumarú) foram selecionados e comparados quanto à produção de lacases em cultivos líquidos estáticos e agitados, utilizando-se o Pleurotus ostreatus, um basidiomiceto produtor de lacase, como referência. A maior atividade de lacase foi detectada apenas nos cultivos estáticos do isolado D3 (35U/l em ABTS; 8U/l em e DMP).

RESUMO

In Brazil, a large amount of a fibrous residue is generated as result of soybean (Glycine max) protein production. This material, which is rich in hemicellulose and cellulose, can be used in solid state cultivations for the production of valuable metabolites and enzymes. In this work, we studied the bioconversion of this residue by bacteria strains isolated from water and soil collected in the Amazon region. Five strains among 87 isolated bacteria selected for their ability to produce either celullases or xylanases were cultivated on the aforementioned residue. From strain BL62, identified as Bacillus subtilis, it was obtained a preparation showing the highest specific cellulase activity, 1.08 UI/mg protein within 24 hours of growth. Concerning xylanase, the isolate BL53, also identified as Bacillus subtilis, showed the highest specific activity for this enzyme, 5.19 UI/mg protein within 72 hours of cultivation. It has also been observed the production of proteases that were associated with the loss of cellulase and xylanase activities. These results indicated that the selected microorganisms, and the cultivation process, have great biotechnological potential.

No Brasil, uma grande quantidade de resíduos fibrosos de soja (Glycine max) são gerados no processo de produção de proteína de soja. Estes materiais, ricos em celulose e hemicelulose, podem ser usados como substratos para cultivos microbianos visando a produção de valiosos metabólitos e enzimas. Neste trabalho, estudou-se a produção de enzimas, utilizando estes resíduos, por bactérias isoladas da água e do solo da região amazônica. Cinco cepas, dentre 87 iniciais, foram selecionadas e crescidas em cultivo semi-sólido (CSS). Preparações obtidas do isolado BL 62, identificado como Bacillus subtilis, apresentaram a maior atividade específica para celulase, 1,08 UI/ mg de proteína, em 24 horas de cultivo. No que se refere às xilanases, preparações obtidas do isolado BL 53, também identificado como Bacillus subtilis, apresentaram a maior atividade específica para esta enzima, com um valor de 5,19 UI/ mg de proteína, em 72 horas de cultivo. Também foi demonstrada a produção simultânea de proteases, o que pode ser associado à perda das atividades de celulase e xilanase durante o cultivo. Os resultados indicam que os microrganismos selecionados e o processo de cultivo empregado utilizando resíduo da soja apresentam grande potencial biotecnológico.