Revista Brasileira de Biociências

Diversity, resistance profiles and virulence of Enterococcus spp. from fecal samples of Tadarida brasiliensis urban bats (Brazilian free-tailed bats)

2021-06-09T17:08:20-03:00

We aimed to evaluate the profile of enterococci from fecal samples of urban bats Tadarida brasiliensis collected at Rio Grande do Sul state, southern Brazil. Bat feces were collected and subjected to enterococci species identification and antimicrobial susceptibility tests for rifampicin, erythromycin, norfloxacin, ciprofloxacin, tetracycline, ampicillin, chloramphenicol, streptomycin, gentamicin, linezolid, nitrofurantoin, and vancomycin. The presence of resistance (ermA, ermC, ermB, msrC, vanA, vanB, vanC1, vanC2/3, tetM, tetM, and tetS) and virulence (ace, agg, cylA, esp, and gelE) genes was determined by PCR. In addition, fecal DNA was extracted and subjected to qPCR and PCR to detect the species E. casseliflavus, E. faecalis, E. faecium, E. gallinarum, E. hirae and E. mundtii, and resistance genes, respectively. A total 73 enterococci were isolated, of which E. faecalis, E. casseliflavus, E. gallinarum, and E. mundtii were identified. Resistance phenotypes were observed for rifampicin (n= 53), erythromycin (n= 32), norfloxacin (n= 7), ciprofloxacin (n= 6) and tetracycline (n=1). Of the resistance genes tested in resistant isolates, only ermC and tetM were present. Six vancomycin-susceptible E. faecalis were positive for vanC1 and vanC2/3. Genes gelE, ace, agg, cylA and esp were detected in the isolates. In fecal DNA samples, all analyzed species and the genes ermC, tetM, vanA, vanB and vanC2/3 were observed. We conclude that different species of enterococci are present in feces of T. brasiliensis urban bats. The presence of antibiotic-resistant enterococci in those animals may be related to anthropogenic action and/or linked to the resistome.

Knowledge and beliefs of artisanal fishermen regarding the river dolphins from Middle Tapajós River, Pará state, northern Brazil)

2021-06-09T17:08:26-03:00

Research on the knowledge of artisanal fishermen regarding Amazonian dolphins is scarce, although they are an important source of information for species conservation. We present here the ethnoknowledge of fishermen from the Middle Tapajós River on the biology of the tucuxi (Sotalia fluviatilis) and the Amazon River dolphin (Inia geoffrensis), as well as their beliefs related to both species. Using semi-structured interviews and participant observation, our results show that fishermen have substantial knowledge on the species, having described in detail aspects related to habitat use and group sizes; however, they also have uncertainties about the number and birth period of dolphin species. While local myths and superstitions about the Amazon River dolphin are present in the region, the interviewees do not consider them to be true. We suggest that educational, sensitizing and income-generating activities through dolphin-watching tourism be worked on with fishermen in order to fill knowledge gaps, promote awareness of the ecological importance of species and maintain artisanal fishing in the region.

Insects of forensic importance in Marajó Island, Pará, Brazil

2021-06-09T17:08:31-03:00

A list of insect species associated with porcine carcasses is presented in an area in the Eastern Amazon. The collections occurred during the months of September to November of 2012 (dry season) and April to May of 2013 (rainy season). For each month of collection, a pig carcass with 20kg was used on average, protected by a metal cage. At the end of the collection 2802 insects belonging to three orders were collected: Diptera (77.1%), Coleoptera (22.2%) and Hymenoptera (2.6%). The results presented here corroborate with many studies developed in other regions of Brazil. This is the first preliminary list of insects associated with carcasses in the study area and will serve as a subsidy for further, more detailed studies in the Eastern Amazon.

DNA extraction of Catasetum gladiatorium K.G.Lacerda (Orchidaceae) for use in molecular studies

2021-06-09T17:08:34-03:00

Catasetum gladiatorium is endemic to Brazil, being usually found in areas subjected to environmental disturbances that may affect its genetic diversity. Analyses of genetic diversity require extraction of pure DNA through fast and efficient protocols. We propose here an efficient protocol to extract the DNA of C. gladiatorium for use in molecular analyses. DNA was extracted from leaf tissue using eight protocols based on the CTAB method. We tested: (1) two types of plant material maceration (using STE buffer and liquid nitrogen); (2) two CTAB concentrations (2% and 5%); and (3) two concentrations of β-mercaptoethanol (0% and 2%) in the extraction buffer. We performed amplification reactions with the extracted DNA using two ISSR primers. The methods of plant material maceration influenced the quality and amount of DNA extracted from C. gladiatorium. Maceration with liquid nitrogen allowed us to obtain high-quality DNA in all other variations of the tested protocols. On the other hand, maceration with STE yielded DNA at low concentrations and highly degraded. The best results were obtained using 5% CTAB. The absence of β-mercaptoethanol did not influence the quality of the extracted DNA. PCR demonstrated that DNA extraction using the eight tested protocols allowed for amplification with both ISSR markers. The eight protocols were able to extract amplifiable C. gladiatorium DNA, and may thus all be indicated for future molecular studies on the species.

Reproductive phenology and population structure of Brazilian sassafras (Ocotea odorifera (Vell.) Rohwer - Lauraceae) at its southern limit of geographical distribution

2021-06-09T17:08:38-03:00

O. odorifera (Vell.) Rohwer, a species native to Brazil, has reduced populations due to an exploitation that has been going on for decades, which has led it to be categorized as endangered. There is little biological information on the species populations. We aimed to characterize the reproductive phenology and population structure of the species at its southern limit of distribution, in order to obtain information that defines its conservation status and its regeneration capacity in natural areas. The study was carried out at Dom Pedro de Alcântara municipality, northern coast of Rio Grande do Sul state, southern Brazil, between September 2006 and August 2007. We used circular analysis and semi-quantitative methods to characterize reproductive phenology, and natural area sampling to evaluate population structure. We found seasonality throughout the evaluated phenophases, except the phenophase of small immature fruits, which showed uniform behavior. The species showed loss of regenerative capacity during fruit development. The species population showed predominance of the smallest size classes in regeneration, with some classes having no representatives. We also found that the species has reached critical points to maintain its populations, due to the low amount of available mature fruits and to the absence of classes in regeneration. The population showed characteristics that justify maintaining the species status as endangered.

Action of household antiseptics and disinfectants against Enterococcus sp. isolated from Dilúvio stream, Rio Grande do Sul state, southern Brazil

2021-06-09T17:08:43-03:00

Located in downtown Porto Alegre, Rio Grande do Sul state, southern Brazil, the Dilúvio stream receives waste and domestic sewage inflow daily from several districts of the city. If not properly treated, such wastewater can be the source of different microorganisms like enterococci. In the present study, the activity of household disinfectants and antiseptics was tested against microorganisms isolated from such wastewater. Fifteen disinfectants and six antiseptic products were tested against 28 enterococci isolated from Dilúvio stream by the disk diffusion method. Products showing anti-enterococci activity were subjected to the minimum inhibitory concentration method, which was obtained by diluting products in 50% to 1.563% for 24 and 48 h of exposure. Of the 21 tested products, 13 disinfectants and five antiseptics showed activity against enterococci isolated from the Dilúvio stream. Although most products proved to be efficient when pure (100%), many had their antimicrobial activity efficiency reduced already in the first dilution (50%) and in the 24-h exposure time. Exposure period revealed to be an important factor for bacterial growth, since the time of permanence of compounds may influence the capacity of bacteria to grow. Our study demonstrated that most tested household disinfectants and antiseptics proved to be efficient in controlling antimicrobial-susceptible and -resistant enterococci strains isolated from the Dilúvio stream.

Evaluation of the larvicidal potential of Croton argyrophyllus stem ethanolic extracts on Aedes aegypti

2021-06-09T17:08:46-03:00

Plants are natural sources of bioactive compounds that may possess larvicidal properties against Aedes aegypti, a vector of the dengue, Zika and Chikungunya viruses. A number of studies have been conducted to identify botanical insecticides that can be used to control that vector. We aimed to evaluate the larvicidal activity of Croton argyrophyllus extracts obtained from stems collected during the rainy (RSE) and dry (DSE) seasons against A. aegypti, as well as to perform a phytochemical screening on both extracts. For the bioassays, third-instar larvae of A. aegypti were exposed to five extract concentrations (four replicates per treatment and 30 larvae per replicate). The extract obtained from stems collected during the rainy season showed higher toxicity against A. aegypti larvae than the extract obtained from stems collected during the dry season. The phytochemical screening of ethanol extracts revealed the presence of flavones, flavonoids, flavanones and xanthones in the RSE, and of strong fixed acids, free steroids and triterpenoids in the DSE. Our findings demonstrated the larvicidal potential of the Croton argyrophyllus stem against Aedes aegypti.

First study on the reproductive biology of Justicia brasiliana Roth (Achantaceae) in the Brazilian Pampa

2021-06-09T17:08:49-03:00

The reproductive system of Justicia brasiliana Roth (Acanthaceae), a species from southern South America, so far remains unknown. We aimed to describe the reproductive biology of J. brasiliana as well as to assess the species pollen viability, stigma receptivity, fruit formation and seed viability. The study was conducted at the Irmão Teodoro Luis Botanic Garden in Capão do Leão municipality, Rio Grande do Sul state, southern Brazil. To analyze the species reproductive system, we established five treatments that tested for allogamy and autogamy, in addition to the control group. Pollen viability was determined by grain staining with 2% Carmine Acetic, whereas stigma receptivity was analyzed by hydrogen peroxide deposition on stigmatic papillae. Fruits were analyzed for the number of produced seeds, which themselves were subjected to a germination test to determine their viability. Data was analyzed in the statistical programs Bioestat and SPSS 20.0. J. brasiliana produced fruits at all autogamy and allogamy treatments, which thus enabled us to conclude that the analyzed species has a mixed reproduction system. All treatments yielded viable seeds, except for the control group. Neither pollen viability nor stigma receptivity differed significantly between the stages of flower bud and anthesis.

Effect of water availability on the seed germination of Araucaria angustifolia (Bert.) O. Kuntze

2021-06-09T17:08:52-03:00

Seeds of Araucaria angustifolia (Bert.) O. Kuntze are of high ecological and economic importance, especially in southern Brazil, where they occur naturally with relative abundance. Several studies have focused on the germination and storage of this species seeds. Although it is known that A. angustifolia seeds are recalcitrant and that water content is important for their germination, studies on water availability in the environment are non-existent. In that sense, we evaluated the effect of water potential on the germination of A. angustifolia seeds. Twelve treatments with different water potentials (0, -0.2, -0.4, -0.6, -0.8, -1.0 MPa) were tested. A total 50 seeds (25 whole and 25 scarified) were allocated for each treatment and the germination rate was evaluated. Our results showed that water potential influenced inversely the germination rate, even with the moisture content inside seeds showing no significant variation. Although water availability in the environment does not interfere with water absorption, it does seem to hinder seed germination, probably reducing seed physiological viability.

Plants of Achillea millefolium L. grown under colored shading nets have altered secondary metabolism

2021-06-09T17:08:54-03:00

Here we evaluate the effect of quality and quantity of light on growth and secondary metabolism of Achillea millefolium L. plants. Plants were cultivated under either full light or colored shading nets (blue, red or black). Analyzes were performed after eight weeks of shading and two and four weeks after the removal of the nets. Plants grown under nets presented lower dry weight of leaves and flowers. In addition, the synthesis of phenols and flavonoids decreased in leaves and flowers of shaded plants. On the other hand, the blue net increased the content of essential oil yield in leaves. The concentration of the majority of the compounds analyzed in the essential oil increased when using the black net. Farnesol and chamazulene were the most plenteous compounds in the oil of leaves and flowers in all conditions. Overall, these results indicate that different compounds respond differently to specific light lengths in A. millefolium plants. Thus, the photoselective treatments should be directed to the production of the target metabolite.

New records of Hindsia ramosissima Gardner (Rubiaceae) and assessment of conservation status for Santa Catarina, Southern Brazil

2021-06-09T17:08:57-03:00

This study emphasizes new records of Hindsia ramosissima Gardner (Rubiaceae), expanding their distribution to the Brazilian state of Santa Catarina, besides the assessment of conservation status. We registered eight collections in five municipalities across the Santa Catarina, expanding considerably the austral limit of the species.

Meio século do PPG Botânica da Universidade Federal do Rio Grande do Sul

2021-06-09T17:08:58-03:00

Ao Mestre Amigo

2021-06-09T17:08:59-03:00