RESUMO A injúria renal aguda (IRA) é definida como o declínio rápido da função renal. Seu desenvolvimento está relacionado a quadros clínicos críticos, como sepse, pós-operatório complicado e doenças infecciosas. A cistatina C sérica (CisC) tem a melhor correlação com a taxa de filtração glomerular. A ultrassonografia se destaca por ser altamente acessível e pode ser realizada à beira do leito. Foram selecionados 28 cães, internados em unidade de terapia intensiva, com valores de creatinina sérica <1,6mg/dL e fatores de risco para o desenvolvimento de IRA. Medições de CisC e avaliações ultrassonográficas foram realizadas diariamente por 72 horas. Utilizando-se a dosagem de CisC, 22/28 animais (78,6%) foram considerados portadores de IRA e 17/22 apresentaram ultrassom compatível com alterações de IRA, demonstrando concordância moderada com a dosagem de CisC. O aumento da ecogenicidade cortical renal é a alteração mais prevalente em pacientes críticos, está correlacionado com aumentos séricos de CisC e associado a dano estrutural renal.

ABSTRACT Acute kidney injury (AKI) is defined as the rapid decline in kidney function. Its development is related to critical clinical statuses, such as sepsis, complicated post-surgical recovery, and infectious diseases. Serum cystatin C (CysC) has the best correlation with the glomerular filtration rate. Ultrasonography stands out because it is highly accessible and can be done at the bedside. Twenty-eight dogs admitted to the intensive care unit with serum creatinine values <1.6 mg/dL and at-risk factors of AKI development were selected. CysC measurements and ultrasound assessments were performed daily for 72 hours. Using CysC dosage, 22/28 animals (78.6%) were considered to have AKI, and 17/22 had ultrasound compatible with AKI changes, demonstrating moderate agreement with CysC dosage. Increased cortical renal echogenicity is the most prevalent alteration in critically ill patients and is correlated with serum increases in CysC and is associated with renal structural damage.

RESUMO A estimação da correlação entre dados independentes usando estimadores clássicos, como o coeficiente de Pearson, está bem estabelecida na literatura. No entanto, tais estimadores são inadequados para analisar a correlação entre dados dependentes. Existem vários tipos de dependência, sendo as dependências serial (temporal) e espacial as mais comuns, as quais são inerentes aos dados de várias áreas. Usando uma análise de série temporal bivariada pode-se avaliar a relação entre duas séries. Além disso, como uma série temporal pode estar relacionada com outra em alguma defasagem de tempo (seja para o passado ou para o futuro), é essencial também considerar correlações defasadas. A função de correlação cruzada (CCF), que assume que cada série tem uma distribuição normal e não é autocorrelacionada, é usada com freqüência. No entanto, mesmo quando uma série temporal é normalmente distribuída, a autocorrelação ainda é inerente a uma ou ambas séries temporais, comprometendo as estimativas obtidos usando o CCF e suas interpretações. Como uma alternativa a este problema, a análise usando a correlação cruzada wavelet (WCC) foi proposta. O WCC é baseado na transformada wavelet não decimada (NDWT), a qual é uma transformação invariante à translação e decompõe dados dependentes em múltiplas escalas, cada uma representando o comportamento de uma banda de frequências diferente. Para demonstrar a aplicabilidade deste método, dados simulados e reais de séries temporais de diferentes processos estocásticos foram analisados. Os resultados demonstraram que as análises baseadas em o CCF pode não representar a realidade; no entanto, o WCC pode ser usado para identificar corretamente a correlação em cada escala. Além disso, o intervalo de confiança (IC) para os resultados da análise do WCC foi estimado para determinar a significância estatística.

ABSTRACT The estimation of the correlation between independent data sets using classical estimators, such as the Pearson coefficient, is well established in the literature. However, such estimators are inadequate for analyzing the correlation among dependent data. There are several types of dependence, the most common being the serial (temporal) and spatial dependence, which are inherent to the data sets from several fields. Using a bivariate time-series analysis, the relation between two series can be assessed. Further, as one time series may be related to an other with a time offset (either to the past or to the future), it is essential to also consider lagged correlations. The cross-correlation function (CCF), which assumes that each series has a normal distribution and is not autocorrelated, is used frequently. However, even when a time series is normally distributed, the autocorrelation is still inherent to one or both time series, compromising the estimates obtained using the CCF and their interpretations. To address this issue, analysis using the wavelet crosscorrelation (WCC) has been proposed. WCC is based on the non-decimated wavelet transform (NDWT), which is translation invariant and decomposes dependent data into multiple scales, each representing the behavior of a different frequency band. To demonstrate the applicability of this method, we analyze simulated and real time series from different stochastic processes. The results demonstrated that analyses based on the CCF can be misleading; however, WCC can be used to correctly identify the correlation on each scale. Furthermore, the confidence interval (CI) for the results of the WCC analysis was estimated to determine the statistical significance.

RESUMO Devido sua habilidade de localização tempo-frequência, a Transformada wavelet tem sido aplicada em várias áreas de pesquisa envolvendo análise e processamento de dados, frequentemente substituindo a convencional Transformada de Fourier. A TransformadaWavelet Discreta tem um grande potencial de aplicação¸ destacando-se como uma importante ferramenta na compressão de sinal, processamento de imagem e sinal, suavização e filtragem de ruídos em dados. Ela também apresenta vantagens sobre a versão contínua por causa de sua fácil implementação, bom desempenho computacional e reconstrução perfeita do sinal após inversão. No entanto, a decimação requerida no cálculo da Transformada Wavelet Discreta a torna variante à translação e não apropriada para algumas aplicaões, tais como análise de sinais ou séries temporais. Por outro lado, a Transformada Wavelet Discreta Não Decimada é invariante à translação, porque elimina o processo de decimação, e consequentemente, é mais apropriada para identificar comportamentos estacionários e não estacionários presentes no sinal. No entanto, a Transformada Wavelet Não Decimada tem sido pouco usada na literatura. Esse artigo pretende mostrar as vantagens do uso na Transformada Wavelet Não Decimada na análise de sinais. Os principais aspectos teóricos e práticos da análise multiescala de séries temporais a partir das wavelets não decimadas, em termos de sua formulação usando o mesmo algoritmo piramidal da Transformada Wavelet Decimada, são apresentados. Por fim, aplicações com séries temporais simuladas e reais comparam o desempenho das transformadas wavelet decimada e não decimada, demonstrando a superioridade da wavelet não decimada, principalmente devido à análise invariante a translação, detecção de padrões e uma reconstrução mais perfeita do sinal.

ABSTRACT Due to the ability of time-frequency location, the wavelet transform has been applied in several areas of research involving signal analysis and processing, often replacing the conventional Fourier transform. The discrete wavelet transform has great application potential, being an important tool in signal compression, signal and image processing, smoothing and de-noising data. It also presents advantages over the continuous version because of its easy implementation, good computational performance and perfect reconstruction of the signal upon inversion. Nevertheless, the downsampling required in the computation of the discrete wavelet transform makes it shift variant and not appropriated to some applications, such as for signals or time series analysis. On the other hand, the Non-Decimated Discrete Wavelet Transform is shift-invariant because it eliminates the downsampling and, consequently, is more appropriate for identifying both stationary and non-stationary behaviors in signals. However, the non-decimated wavelet transform has been underused in the literature. This paper intends to show the advantages of using the non-decimated wavelet transform in signal analysis. The main theoretical and practical aspects of the multi-scale analysis of time series from non-decimated wavelets in terms of its formulation using the same pyramidal algorithm of the decimated wavelet transform was presented. Finally, applications with a simulated and real time series compare the performance of the decimated and non-decimated wavelet transform, demonstrating the superiority of non-decimated one, mainly due to the shift-invariant analysis, patterns detection and more perfect reconstruction of a signal.

Chitinases are hydrolases that degrade chitin, a polymer of N-acetylglucosamine linked β(1-4) present in the exoskeleton of crustaceans, insects, nematodes and fungal cell walls. A metagenome fosmid library from a wastewater-contaminated soil was functionally screened for chitinase activity leading to the isolation and identification of a chitinase gene named metachi18A. The metachi18A gene was subcloned and overexpressed in Escherichia coli BL21 and the MetaChi18A chitinase was purified by affinity chromatography as a 6xHis-tagged fusion protein. The MetaChi18A enzyme is a 92-kDa protein with a conserved active site domain of glycosyl hydrolases family 18. It hydrolyses colloidal chitin with an optimum pH of 5 and temperature of 50°C. Moreover, the enzyme retained at least 80% of its activity in the pH range from 4 to 9 and 98% at 600 mM NaCl. Thin layer chromatography analyses identified chitobiose as the main product of MetaChi18A on chitin polymers as substrate. Kinetic analysis showed inhibition of MetaChi18A activity at high concentrations of colloidal chitin and 4-methylumbelliferyl N,N′-diacetylchitobiose and sigmoid kinetics at low concentrations of colloidal chitin, indicating a possible conformational change to lead the chitin chain from the chitin-binding to the catalytic domain. The observed stability and activity of MetaChi18A over a wide range of conditions suggest that this chitinase, now characterized, may be suitable for application in the industrial processing of chitin.

The conventional method for quantification of polyhydroxyalkanoates based on whole-cell methanolysis and gas chromatography (GC) is laborious and time-consuming. In this work, a method based on flow cytometry of Nile red stained bacterial cells was established to quantify poly-3-hydroxybutyrate (PHB) production by the diazotrophic and plant-associated bacteria, Herbaspirillum seropedicae and Azospirillum brasilense. The method consists of three steps: i) cell permeabilization, ii) Nile red staining, and iii) analysis by flow cytometry. The method was optimized step-by-step and can be carried out in less than 5 min. The final results indicated a high correlation coefficient (R2=0.99) compared to a standard method based on methanolysis and GC. This method was successfully applied to the quantification of PHB in epiphytic bacteria isolated from rice roots.

NifA is the transcriptional activator of the nif genes in Proteobacteria. It is usually regulated by nitrogen and oxygen, allowing biological nitrogen fixation to occur under appropriate conditions. NifA proteins have a typical three-domain structure, including a regulatory N-terminal GAF domain, which is involved in control by fixed nitrogen and not strictly required for activity, a catalytic AAA+ central domain, which catalyzes open complex formation, and a C-terminal domain involved in DNA-binding. In Herbaspirillum seropedicae, a β-proteobacterium capable of colonizing Graminae of agricultural importance, NifA regulation by ammonium involves its N-terminal GAF domain and the signal transduction protein GlnK. When the GAF domain is removed, the protein can still activate nif genes transcription; however, ammonium regulation is lost. In this work, we generated eight constructs resulting in point mutations in H. seropedicae NifA and analyzed their effect on nifH transcription in Escherichia coli and H. seropedicae. Mutations K22V, T160E, M161V, L172R, and A215D resulted in inactive proteins. Mutations Q216I and S220I produced partially active proteins with activity control similar to wild-type NifA. However, mutation G25E, located in the GAF domain, resulted in an active protein that did not require GlnK for activity and was partially sensitive to ammonium. This suggested that G25E may affect the negative interaction between the N-terminal GAF domain and the catalytic central domain under high ammonium concentrations, thus rendering the protein constitutively active, or that G25E could lead to a conformational change comparable with that when GlnK interacts with the GAF domain.

Devido às inúmeras possibilidades de aplicação, a teoria de wavelets tem sido utilizada nas mais diversas áreas de pesquisa. A Transformada Wavelet Discreta é a versão mais conhecida. Porém, o processo de decimação necessário para seu cálculo, faz com que ela seja sensível à origem, o que para algumas aplicações não é o ideal, principalmente em séries temporais. Ao contrário, a Transformada Wavelet Discreta Não Decimada é invariante à translação, pois leva em consideração todos os elementos da amostra, de modo a representar uma série temporal com o mesmo número de coeficientes em cada escala, tendo o processo de decimação eliminado. Neste artigo pretende-se apresentar os aspectos teóricos da análise multiescala/multirresolução de séries temporais não estacionárias a partir de wavelets não decimadas utilizando, em termos de sua implementação, o mesmo algoritmo piramidal da transformada wavelet não decimada. Uma aplicação com a série temporal real do efeito da cintilação ionosférica sobre sinais de satélite GPS será investigada. Resultados desta investigação das séries obtidas dos índices S4 de cintilação indicam a presença de um padrão que se repete na série em dias consecutivos. Através da decomposição em multiescala por wavelets, esse efeito periódico diário pode ser identificado nas escalas mais suaves do periodograma wavelet, estimado e corrigido da série temporal original. Portanto, este artigo apresenta uma metodologia inovadora para a análise dos efeitos da cintilação ionosférica sobre sinais GPS, e dá um primeiro passo em direção a separar o efeito da cintilação de outros efeitos que podem influenciar sua análise.

Due to the numerous application possibilities, the theory of wavelets has been applied in several areas of research. The Discrete Wavelet Transform is the most known version. However, the downsampling required for its calculation makes it sensitive to the origin, what is not ideal for some applications, mainly in time series. On the other hand, the Non-Decimated Discrete Wavelet Transform is shift invariant, because it considers all the elements of the sample, by eliminating the downsampling and, consequently, represents a time series with the same number of coefficients at each scale. In the present paper, the objective is to present the theorical aspects of the a multiscale/multiresolution analysis of non-stationary time series from non-decimated wavelets in terms of its implementation using the same pyramidal algorithm of the decimated wavelet transform. An application with real time series of the effect of the ionospheric scintillation on GPS satellite signals is investigated. Results obtained in this investigation of the time series of the S4 scintillation index indicate the presence of a pattern that is repeated in the series on consecutive days. Through decomposition in multiscale by wavelets, this periodic daily effect could be identified in smoother scales of the wavelet periodogram, estimated and corrected from the original time series. Therefore, this paper presents an innovative methodology for the analysis of the effects of ionospheric scintillation on GPS signals, and take a first step toward separating the effect of scintillation in relations the other effects that may influence its analysis.

A identificação de variações cíclicas e sazonais é muito importante em séries temporais. Neste artigo, objetiva-se identificar a presença de variações cíclicas e sazonais nos índices do efeito do multicaminho em estações GPS (Global Positioning System) de monitoramento contínuo. Devido ao modelo usado na obtenção de tais series, não deveriam existir variações cíclicas nas mesmas, pelo menos devido ao multicaminho. No sentido de identificar a presença de variações cíclicas nestas séries, foram analisados correlogramas e periodogramas de Fourier. Para confirmar a presença de sazonalidade estatisticamente significativa, foi utilizado o teste de Fisher para sazonalidade. Além disso, modelos harmônicos foram ajustados para verificar em que meses do ano os picos dos efeitos cíclicos estão ocorrendo. As possíveis causas dos efeitos são apontadas, as quais direcionarão investigações futuras, bem como a análise e correlações com outras séries. A importância desta análise se deve principalmente ao fato de que erros nos sinais coletados afetarão a acurácia dos resultados de toda a comunidade que usam dados GPS diretamente ou indiretamente.

The identification of the cyclical and seasonal variations can be very important in time series. In this paper, the aim is to identify the presence of cyclical or seasonal variations in the indices of the multipath effect on continuous GPS (Global Positioning System) stations. Due to the model used to obtain these indices, there should not have cyclical variations in these series, at least due to the multipath effect. In order to identify the presence of cyclical variations in these series, correlograms and Fourier periodograms were analyzed. The Fisher test for seasonality was applied to confirm the presence of statistical significant seasonality. In addition, harmonic models were adjusted to check in which months of the year the cyclical effects are occurring in the multipath indices. The possible causes of these effects are pointed out, which will direct the upcoming investigations, as well as the analysis and correlations of other series. The importance of this analysis is mainly due to the fact that errors in the collected signals of these stations will directly influence the accuracy of the results of the whole community that directly or indirectly uses GPS data.

Avaliou-se a inclusão do farelo residual de manga sem casca como fonte de carboidrato na relação proteína:carboidrato (PB:CHO) sobre o desempenho e a composição química da carcaça em juvenis de pacamãs. Foram utilizados 150 peixes (11,31±0,96g) estocados em 16 caixas de 500L, alimentados três vezes ao dia (10% peso vivo), em um sistema de recirculação de água com biofiltro. Os tratamentos consistiram em quatro dietas experimentais com níveis decrescentes da relação entre proteína bruta e carboidrato (1,40; 0,94; 0,56 e 0,29), com quatro repetições cada tratamento. Ao final de 60 dias, foram avaliados o desempenho zootécnico (ganho de peso médio final, taxa de crescimento específico, consumo total de ração aparente, conversão alimentar aparente, rendimento de carcaça, sobrevivência) e a composição físico-química da carcaça. As relações de proteína:carboidrato afetaram todas as variáveis de desempenho (P<0,05), com exceção da sobrevivência (P>0,05). Os valores da composição química da carcaça foram alterados, com exceção da matéria mineral, do pH e da umidade. A farinha de manga pode ser utilizada na proporção de até 15% na ração de pacamã, estabelecendo uma relação 1,40 PB:CHO, sem prejudicar o desempenho zootécnico e a composição química da carcaça.

We evaluated the inclusion of peeled-mango waste meal as a source of carbohydrate in the protein:carbohydrate ratio (CP:CH) on performance and chemical composition of pacamã (Lophiosilurus alexandri) juveniles. One hundred and fifty fish (11.31±0.96g) were stocked in sixteen 500 L tanks, fed three times daily (10% of live weight), in a system with water recirculation with biofilter. The treatments consisted of four experimental diets with decreasing levels of the ratio between crude protein and carbohydrate (1.40, 0.94, 0.56 and 0.29), with four replications per treatment. At the end of 60 days, we evaluated animal performance (final average weight gain, specific growth rate, total apparent feed intake, carcass yield, survival) and physicochemical composition of the carcass. The protein:carbohydrate ratios affected all performance variables (P<0.05), except for survival (P>0.05). The carcass chemical composition variables were modified, except for mineral matter, pH and moisture. Mango meal can be used at the proportion of up to 15% in the diet for pacamã, establishing a CP:CHO ratio of 1.40 without impairing animal performance and the carcass chemical composition.

RESUMO Agentes químicos têm sido usados para auxiliar na inibição da formação do biofilme e impedir desenvolvimento da doença periodontal (DP). O objetivo deste estudo foi avaliar radiograficamente a ação do extrato de própolis na progressão da DP induzida em ratos. Foram utilizados 48 ratos Wistar, divididos em 4 grupos (n=12): Controle, Pincel, Própolis e Clorexidina. Os grupos foram subdivididos para análise aos 7 e 21 dias. A progressão da DP foi avaliada radiograficamente pela distância entre a junção cemento-esmalte e a crista óssea alveolar na face mesial do 1º molar inferior. A perda óssea foi significativamente menor nos animais do grupo própolis em ambos os períodos (p ≤ 0,01). Concluiu-se por análise radiográfica que a aplicação tópica do extrato de própolis interfere reduzindo a progressão da doença periodontal induzida por ligadura em ratos, demonstrando a importância desse composto como substância auxiliar no tratamento periodontal.

ABSTRACT Chemical agents have been used to assist on inhibiting biofilm formation and on preventing the development of periodontal disease (PD). The aim of this study was to radiographically evaluate the action of propolis extract on the progression of PD induced in rats. 48 Wistar rats were divided into 4 groups (n = 12): Control, Brush, Propolis and Chlorhexidine. The groups were subdivided for analysis at 7 and 21 days. The progression of the periodontal disease was radiographically assessed by the distance between the cement-enamel junction and the alveolar bone crest mesial of the 1st molar. Bone loss was significantly lower in the Propolis group in both periods (p ≤ 0.01). By radiographic analysis, it is concluded that the topical application of propolis extract interferes by reducing the progression of ligature-induced periodontal disease in rats, demonstrating the importance of this compound as an auxiliary substance in periodontal treatment.

O presente relato descreve os achados clínicos e patológicos de uma heterotopia de pelos difusa associada com hiperplasia endometrial pseudo-placentacional em um útero de uma cadela. Macroscopicamente, o útero estava intensamente aumentado de volume e espesso, a superfície do endométrio estava irregular e recoberta com pelos pretos semelhantes aos pelos da cadela. Histologicamente, heterotopia de pelos associada com hiperplasia endometrial pseudoplacentacional foi observada.

The present report describes the clinical and pathological findings related to diffuse heterotopic hairs associated with pseudo-placentational endometrial hyperplasia in a canine uterus. Macroscopically, the uterus was intensely enlarged and thicker, and the endometrial surface was irregular and covered with black hairs similar to the hairs of the bitch. Histologically, heterotopic hairs associated with pseudo-placentational endometrial hyperplasia were observed.

DNA repair is crucial to the survival of all organisms. The bacterial RecA protein is a central component in the SOS response and in recombinational and SOS DNA repairs. The RecX protein has been characterized as a negative modulator of RecA activity in many bacteria. The recA and recX genes of Herbaspirillum seropedicae constitute a single operon, and evidence suggests that RecX participates in SOS repair. In the present study, we show that the H. seropedicae RecX protein (RecX Hs) can interact with the H. seropedicaeRecA protein (RecA Hs) and that RecA Hs possesses ATP binding, ATP hydrolyzing and DNA strand exchange activities. RecX Hs inhibited 90% of the RecA Hs DNA strand exchange activity even when present in a 50-fold lower molar concentration than RecA Hs. RecA Hs ATP binding was not affected by the addition of RecX, but the ATPase activity was reduced. When RecX Hs was present before the formation of RecA filaments (RecA-ssDNA), inhibition of ATPase activity was substantially reduced and excess ssDNA also partially suppressed this inhibition. The results suggest that the RecX Hs protein negatively modulates the RecA Hs activities by protein-protein interactions and also by DNA-protein interactions.

Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the N-truncated protein in response to fixed nitrogen levels. We also used pull-down assays to show in vitro interaction between the purified N-terminal GAF domain of NifA and the GlnB protein. The results showed that A. brasilense GlnB interacts directly with the NifA N-terminal domain and this interaction is dependent on the presence of ATP and 2-oxoglutarate.

Azospirillum brasilense is a nitrogen-fixing bacterium associated with important agricultural crops such as rice, wheat and maize. The expression of genes responsible for nitrogen fixation (nif genes) in this bacterium is dependent on the transcriptional activator NifA. This protein contains three structural domains: the N-terminal domain is responsible for the negative control by fixed nitrogen; the central domain interacts with the RNA polymerase σ54 co-factor and the C-terminal domain is involved in DNA binding. The central and C-terminal domains are linked by the interdomain linker (IDL). A conserved four-cysteine motif encompassing the end of the central domain and the IDL is probably involved in the oxygen-sensitivity of NifA. In the present study, we have expressed, purified and characterized an N-truncated form of A. brasilense NifA. The protein expression was carried out in Escherichia coli and the N-truncated NifA protein was purified by chromatography using an affinity metal-chelating resin followed by a heparin-bound resin. Protein homogeneity was determined by densitometric analysis. The N-truncated protein activated in vivo nifH::lacZ transcription regardless of fixed nitrogen concentration (absence or presence of 20 mM NH4Cl) but only under low oxygen levels. On the other hand, the aerobically purified N-truncated NifA protein bound to the nifB promoter, as demonstrated by an electrophoretic mobility shift assay, implying that DNA-binding activity is not strictly controlled by oxygen levels. Our data show that, while the N-truncated NifA is inactive in vivo under aerobic conditions, it still retains DNA-binding activity, suggesting that the oxidized form of NifA bound to DNA is not competent to activate transcription.

Sugarcane is an important agricultural product of Brazil, with a total production of more than 500 million tons. Knowledge of the bacterial community associated with agricultural crops and the soil status is a decisive step towards understanding how microorganisms influence crop productivity. However, most studies aim to isolate endophytic or rhizosphere bacteria associated with the plant by culture-dependent approaches. Culture-independent approaches allow a more comprehensive view of entire bacterial communities in the environment. In the present study, we have used this approach to assess the bacterial community in the rhizosphere soil of sugarcane at different times and under different nitrogen fertilization conditions. At the high taxonomic level, few differences between samples were observed, with the phylum Proteobacteria (29.6%) predominating, followed by Acidobacteria (23.4%), Bacteroidetes (12.1%), Firmicutes (10.2%), and Actinobacteria (5.6%). The exception was the Verrucomicrobia phylum whose prevalence in N-fertilized soils was approximately 0.7% and increased to 5.2% in the non-fertilized soil, suggesting that this group may be an indicator of nitrogen availability in soils. However, at low taxonomic levels a higher diversity was found associated with plants receiving nitrogen fertilizer. Bacillus was the most predominant genus, accounting for 19.7% of all genera observed. Classically reported nitrogen-fixing and/or plant growth-promoting bacterial genera, such as Azospirillum, Rhizobium, Mesorhizobium, Bradyrhizobium, and Burkholderia were also found although at a lower prevalence.