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ABSTRACT: Organic agriculture comprises farming practices that discard synthetic pesticides and fertilizers. Tomato production demands huge amounts of fertilizers and pesticides. Improving efficiency of the inputs allowed for organic tomato production is a challenge to upgrade yields. Thereby, we studied the effects of the inoculation of the arbuscular mycorrhizal fungus (AMF) Rhizophagus clarus, supplying rock thermophosphate and bioactivator, alone or associated, on tomato development and yield. The experiment was achieved in a greenhouse using undetermined tomato cv. BRS-Nagai sown in polystyrene trays and afterwards transplanted to pots. Treatments included R. clarus; thermophosphate (TH) (130 g/pot); bioactivator (PenergeticK® + Penergetic®) (BI); R. clarus + TH; R. clarus + BI; R. clarus + TH+ BI and TH + BI and control (CO). From the flowering onset, plant height, height of insertion of first truss, trusses space, length, and also the diameter and fresh weight of ripe fruits of the three first trusses were assessed. AMF colonization in the roots and macronutrients in leaves and petioles were also measured. Trusses spacing variable was affected by mycorrhiza and thermophosphate. R. clarus inoculation incremented 10 and 31.85% of fresh mass of ripe fruits and mass of ripe fruits per plant, respectively. Soluble solids contents in fruits and N, P and K in the leaves and petioles were similar among treatments. AMF colonization decreased on thermophosphate fertilized plants and increased in bioactivator treatment. Results showed that root inoculation with R. clarus promoted better plant development and yield and may be used as biological inoculant mostly on organic tomato production.

Candida albicans remains the most common agent of candidiasis worldwide. This yeast is generally sensitive to most antifungals, however, the emergence of azole-resistant C. albicans has been reported. In addition, this microorganism can form biofilms on various surfaces, making it difficult to treat infections. In this study, the effect of secondary metabolites of Pseudomonas aeruginosa strain LV on planktonic and sessile cells of C. albicans, with different genotypes and susceptibility profile to fluconazole and voriconazole, was evaluated. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the semi-purified fraction F4a ranged from 1.56 to 6.25 μg/mL and 6.25 to 25 μg/mL, respectively. Fluopsin C appears to be the antifungal component of F4a. The semi-purified fraction and fluopsin C showed fungicidal activity, dose and time dependent. F4a caused severe damage to the morphology and ultrastructure of planktonic fungal cells, and significantly reduced the viability of 24-hour biofilms, with MIC for sessile cells from 12.5 to 25.0 μg/mL. However, cytotoxicity was detected in mammalian cells for F4a and fluopsin C at concentrations that showed antifungal activity. These results indicate that fluopsin C may be a prototype for the development of new antifungals for C. albicans.

Acinetobacter baumannii emerged as one of the most important pathogens for the development of new antimicrobials due to the worldwide detection of isolates resistant to all commercial antibiotics, especially in nosocomial infections. Biofilm formation enhances A. baumannii survival by impairing antimicrobial action, being an important target for new antimicrobials. Fluopsin C (FlpC) is an organocupric secondary metabolite with broad-spectrum antimicrobial activity. This study aimed to evaluate the antibiofilm activity of FlpC in established biofilms of extensively drug-resistant A. baumannii (XDRAb) and the effects of its combination with polymyxin B (PolB) on planktonic cells. XDRAb susceptibility profiles were determined by Vitek 2 Compact, disk diffusion, and broth microdilution. FlpC and PolB interaction was assessed using the microdilution checkerboard method and time–kill kinetics. Biofilms of XDRAb characterization and removal by FlpC exposure were assessed by biomass staining with crystal violet. Confocal Laser Scanning Microscopy was used to determine the temporal removal of the biofilms using DAPI, and cell viability using live/dead staining. The minimum inhibitory concentration (MIC) of FlpC on XDRAb was 3.5 µg mL−1. Combining FlpC + PolB culminated in an additive effect, increasing bacterial susceptibility to both antibiotics. FlpC-treated 24 h biofilms reached a major biomass removal of 92.40 ± 3.38% (isolate 230) using 7.0 µg mL−1 FlpC. Biomass removal occurred significantly over time through the dispersion of the extracellular matrix and decreasing cell number and viability. This is the first report of FlpC’s activity on XDRAb and the compound showed a promissory response on planktonic and sessile cells, making it a candidate for the development of a new antimicrobial product.

Pseudomonas are known as higher producers of secondary metabolites with antimicrobial properties and plant growth promoters, including resistance induction. These mechanisms should be an alternative to pesticide use in crop production. Phakopsora pachyrhizi causes Asian soybean rust, representing a high loss of yield around the world. The objective of this paper was to evaluate the application of secondary metabolites produced by Pseudomonas aeruginosa LV strain from the semi-purified fraction F4A in soybean plants to induce plant resistance against P. pachyrhizi in field conditions. The experimental design was performed in randomized blocks with three replicates using two F4A doses (1 and 10 μg mL−1) combined or not with fungicides (Unizeb Gold® or Sphere Max®). The control treatment, with Uni + Sph, saponins, flavonoids, and sphingolipids, showed higher intensities in the plants. In contrast, plants treated with the F4A fraction mainly exhibited fatty acid derivatives and some non-identified compounds with nitrogen. Plants treated with Sphere Max®, with or without F4A10, showed higher intensities of glycosylated flavonoids, such as kaempferol, luteolin, narigenin, and apigenin. Plants treated with F4A showed higher intensities of genistein and fatty acid derivatives. These increases in flavonoid compound biosynthesis and antioxidant properties probably contribute to the protection against reactive oxygen species (ROS).

The increasing need for sustainable agricultural practices, combined with the demand for enhanced crop productivity, has led to a growing interest in utilizing microorganisms for biocontrol of diseases and pests, as well as for growth promotion. In Brazilian agriculture, the use of plant growth-promoting rhizobacteria (PGPR) and plant growth-promoting fungi (PGPF) has become increasingly prevalent, with a corresponding rise in the number of registered microbial inoculants each year. PGPR and PGPF occupy diverse niches within the rhizosphere, playing a crucial role in soil nutrient cycling and influencing a wide range of plant physiological processes. This review examines the primary mechanisms employed by these microbial agents to promote growth, as well as the strategy of co-inoculation to enhance product efficacy. Furthermore, we provide a comprehensive analysis of the microbial inoculants currently available in Brazil, detailing the microorganisms accessible for major crops, and discuss the market’s prospects for the research and development of novel products in light of current challenges faced in the coming years.

Abstract Soybean and maize are some of the main drivers of Brazilian agribusiness. However, biotic and abiotic factors are of great concern, causing huge grain yield and quality losses. Phosphorus (P) deficiency is important among the abiotic factors because most Brazilian soils have a highly P-fixing nature. Thus, large amounts of phosphate fertilizers are regularly applied to overcome the rapid precipitation of P. Searching for alternatives to improve the use of P by crops is essential to reduce the demand for P input. The use of multifunctional rhizobacteria can be considered one of these alternatives. In this sense, the objective of the present work was to select and validate bacterial strains with triple action (plant growth promoter, phosphate solubilizer, and biocontrol agent) in maize and soybean, aiming to develop a multifunctional microbial inoculant for Brazilian agriculture. Bacterial strains with high indole acetic acid (IAA) production, phosphate solubilization, and antifungal activity against soil pathogenic fungi (Rhizoctonia solani, Macrophomina phaseolina, and Fusarium solani) were selected from the maize rhizosphere. Then, they were evaluated as growth promoters in maize under greenhouse conditions. Based on this study, strain 03 (Ag75) was selected due to its high potential for increasing biomass (root and shoot) and shoot P content in maize. This strain was identified through genomic sequencing as Bacillus velezensis. In field experiments, the inoculation of this bacterium increased maize and soybean yields by 17.8 and 26.5%, respectively, compared to the control (25 kg P2O5). In addition, the inoculation results did not differ from the control with 84 kg P2O5, indicating that it is possible to reduce the application of phosphate in these crops. Thus, the Ag75 strain has great potential for developing a multifunctional microbial inoculant that combines the ability to solubilize phosphate, promote plant growth, and be a biocontrol agent for several phytopathogenic fungi.

Candida auris has been found to be a persistent colonizer of human skin and a successful pathogen capable of causing potentially fatal infection, especially in immunocompromised individuals. This fungal species is usually resistant to most antifungal agents and has the ability to form biofilms on different surfaces, representing a significant therapeutic challenge. Herein, the effect of metabolites of Pseudomonas aeruginosa LV strain, alone and combined with biologically synthesized silver nanoparticles (bioAgNP), was evaluated in planktonic and sessile (biofilm) cells of C. auris. First, the minimal inhibitory and fungicidal concentration values of 3.12 and 6.25 μg/mL, respectively, were determined for F4a, a semi-purified bacterial fraction. Fluopsin C and indolin-3-one seem to be the active components of F4a. Like the semi-purified fraction, they showed a time- and dose-dependent fungicidal activity. F4a and bioAgNP caused severe changes in the morphology and ultrastructure of fungal cells. F4a and indolin-3-one combined with bioAgNP exhibited synergistic fungicidal activity against planktonic cells. F4a, alone or combined with bioAgNP, also caused a significant decrease in the number of viable cells within the biofilms. No cytotoxicity to mammalian cells was detected for bacterial metabolites combined with bioAgNP at synergistic concentrations that presented antifungal activity. These results indicate the potential of F4a combined with bioAgNP as a new strategy for controlling C. auris infections.

Considering the worrying emergence of multidrug resistance, including in animal husbandry and especially in food-producing animals, the need to detect antimicrobial resistance strains in poultry environments is relevant, mainly considering a One Health approach. Thus, this study aimed to conduct longitudinal monitoring of antimicrobial resistance in broiler chicken farms, with an emphasis on evaluating the frequency of resistance to fosfomycin and β-lactams. Escherichia coli was isolated from broiler chicken farms (cloacal swabs, meconium, poultry feed, water, poultry litter, and Alphitobius diaperinus) in northern Paraná from 2019 to 2020 during three periods: the first period (1st days of life), the second period (20th to 25th days of life), and third period (40th to 42nd days of life). Antibiogram tests and the detection of phenotypic extended-spectrum β-lactamase (ESBL) were performed, and they were confirmed by seaching for genes from the blaCTX–M group. The other resistance genes searched were mcr-1 and fosA3. Some ESBL blaCTX–M–1 group strains were selected for ESBL identification by sequencing and enterobacterial repetitive intergenic consensus-polymerase chain reaction analysis. To determine the transferability of the blaCTX–M–1– and fosA3-carrying plasmids, strains were subjected to conjugation experiments. A total of 507 E. coli were analyzed: 360 from cloacal swabs, 24 from meconium samples, 3 from poultry feed samples, 18 from water samples, 69 from poultry litter samples, and 33 from A. diaperinus samples. Among the strain isolate, 80% (406/507) were multidrug-resistant (MDR), and 51% (260/507) were ESBL-positive, with the blaCTX–M–1 group being the most frequent. For the fosA3 gene, 68% (344/507) of the strains isolated were positive, deserves to be highlighted E. coli isolated from day-old chickens (OR 6.34, CI 2.34–17.17), when compared with strains isolated from other origins (poultry litter, A. diaperinus, water, and poultry feed). This work alerts us to the high frequency of the fosA3 gene correlated with the CTX-M-1 group (OR 3.57, CI 95% 2.7–4.72, p < 0.05), especially the blaCTX–M–55 gene, in broiler chickens. This profile was observed mainly in day-old chicken, with a high percentage of E. coli that were MDR. The findings emphasize the importance of conducting longitudinal monitoring to detect the primary risk points during poultry production.

At least 20–40% of annual losses of avocado crops are caused by pathogenic fungi. The chemical treatments of these diseases are inefficient, cause environmental pollution and are increasingly restricted by international laws. This work aimed to assess the biocontrol capacity of a bacterial extract to protect avocado fruits and plants from pathogen infections. Extracts from the bacterial isolate Serratia sp. ARP5.1 were obtained from liquid fermentations in a biorreactor. A body rot postharvest infection model with Colletotrichum gloeosporioides on fruits was developed. Moreover, packaging conditions were simulated using the bacterial extract and the commercial fungicide prochloraz as a positive control. Additionally, seedlings infections with Phytophthora cinnamomi were performed on two types of avocado (West Indian race and cv. Hass). The Area Under Disease Progress Curve (AUDPC) was recorded using the bacterial extract and a commercial product with fosetyl-aluminium as treatments. The bacterial extract significantly reduced infections by C. gloeosporioides on injured avocado fruits at 31.1 μg mL−1. Intact fruits were also protected against body rot infections at the same concentration and showed no significant differences with the commercial fungicide. On the other hand, AUDPC in the seedlings was significantly reduced with the extract treatment at 3 μg mL−1 compared to the control. However, a possible phytotoxicity effect of the extract was evidenced in the seedlings and confirmed by pathogen recovery and tests on Raphanus sativus seedlings. Finally, formulations of the extracts (emulsion and emulsifiable concentrate) were prepared, and bioactive stability was assessed for 8 wk. The emulsion formulates demonstrated very stable bioactivity against P. cinnamomi. The extract and the emulsion formulate showed promising results for the control of avocado pathogens. New bioproducts based on this type of active principles could be developed for the benefit of avocado industry.

Fluopsin C (FlpC) is an organocupric secondary metabolite with low-molecular-weight, produced by some Pseudomonas and Streptomyces bacteria. The compound was identified in 1970 as prismatic dark-green crystals, with strong antimicrobial activity against several human and phytopathogens. Due to its high cytotoxicity, research on this compound decreased after the 1970s. During the early 2000s, FlpC gained more attention as a promising compound by which to develop new antimicrobials to control human, animal, and plant pathogens. This study provides an overview of the results pertaining to the in vitro and in vivo antimicrobial activity of pure FlpC, as well as semi-purified fractions containing FlpC, against phytopathogenic microorganisms. Furthermore, the bioprospection history of the extensively researched FlpC-producing Pseudomonas aeruginosa LV strain and the related molecular evidence regarding the compound’s biosynthesis are discussed. Overall, FlpC is proposed to be an important alternative to antimicrobial resistance in human and animal health, and in tackling the negative environmental impacts caused by the exacerbated use of pesticides against phytopathogens.

In the current agronomic context, the adoption of alternative forms of soil management is essential to increase crop yield. Agricultural sustainability requires practices that generate positive impacts and promote an increase in microbiome diversity as a tool to overcome adverse environmental conditions. An important ally is the indigenous arbuscular mycorrhizal fungi (AMF) that can improve plant growth and provide protection against abiotic stress such as metal toxicity. In a greenhouse experiment, this work studied the effect of wheat growth on several parameters of biological activity and functional microbiome in relation to wheat antecedent plant mycotrophy and soil disturbance under Mn stress. When the wheat was planted after highly mycotrophic plants and the soil was not previously disturbed, the results showed a 60% increase in wheat arbuscular colonization and a 2.5-fold increase in dry weight along with higher values of photosynthetic parameters and dehydrogenase activity. Conversely, soil disturbance before wheat planting increased the β-glucosidase activity and the count of manganese oxidizers, irrespectively of antecedent plant, and decreased drastically the wheat dry weight, the AMF colonization and the chlorophyll content compared to the undisturbed treatment. These findings suggest that not only the wheat growth but also the soil functional microbiome associated is affected by the antecedent type of plant and previous soil disturbance imposed. In addition, the improvement in wheat dry weight despite Mn toxicity may rely on shifts in biological activity associated to a well-established and intact ERM early developed in the soil.

The Tectona grandis L.f. (teak) is an important forest species with high economy value in Asia, Africa, and Latin America. In Latin America, Brazil is one of the countries with the most cultivated areas. The cultivation of teak turns out to be challenging because of its high nutritional demand and the need for seedling production by clonal propagation that includes about 90 days in the nursery phase. The optimization of seedling production is necessary for better results in the nursery and to enhance growth in the field. In this way, the well-known advantage of using microorganisms that promote plant development appears as a potential biotechnological approach to be explored and for the implantation of new areas of wood production. In this study, the inoculation of Bacillus subtilis as plant growth-promoting rhizobacteria (PGPR) was evaluated, and Rhizophagus clarus, an arbuscular mycorrhizal fungus (AMF), and the co-inoculation of these microorganisms in the teak seedling production phase can improve the development of commercial plantations under field conditions. Experiments were carried out under greenhouse and field conditions to evaluate four treatments based on the substrate inoculation of the seedlings. Treatments consisted of a non-inoculated control, PGPR inoculation, AMF inoculation, and PGPR + AMF inoculation. The results of the biometric evaluation of seedlings in the greenhouse showed that there was a significant difference in AMF inoculation and PGPR + AMF inoculation in terms of the specific root length and root density treatments, there was also a positive correlation between these two treatments and the absorption of some nutrients, such as P, N, K, Mg, Cu, Mn, and Zn. This response led to an increase between 4.75 and 11.04% in the field growth rate.

The antibiotic activity of metalloantibiotic compounds has been evaluated since the 90s, and many different modes of action were characterized. In the last decade, the effects of secondary metabolites produced by Pseudomonas aeruginosa LV strain, including a cupric compound identified as Fluopsin C, were tested against many pathogenic bacteria strains, proving their high antibiotic activity. In the present study, the bactericidal mechanisms of action of Fluopsin C and the semi-purified fraction F4A were elucidated. The results found in electron microscopy [scanning electron microscopy (SEM) and transmission electronic microscopy (TEM)] demonstrated that both Fluopsin C and F4A are affecting the cytoplasmatic membrane of Gram-positive and Gram-negative bacteria. These results were confirmed by fluorescence microscopy, where these bacteria presented permeabilization of their cytoplasmatic membranes after contact with the semi-purified fraction and pure compound. Using electronic and fluorescence microscopy, along with bacterial mutant strains with marked divisional septum, the membrane was defined as the primary target of Fluopsin C in the tested bacteria.

Asian Soybean Rust (ASR), a disease caused by Phakopsora pachyrhizi, causing yield losses up to 90%. The control is based on the fungicides which may generate resistant fungi. The activation of the plant defense system, should help on ASR control. In this study, secondary metabolites of Pseudomonas aeruginosa LV strain were applied on spore germination and the expression of defense genes in infected soybean plants. The F4A fraction and the pure metabolites were used. In vitro, 10 µg mL−1 of F4A reduced spore germination by 54%, while 100 µg mL−1 completely inhibited. Overexpression of phenylalanine ammonia lyase (PAL), O-methyltransferase (OMT) and pathogenesis related protein-2 (PR-2; glucanases) defense-related genes were detected 24 and 72 h after soybean sprouts were sprayed with an organocopper antimicrobial compound (OAC). Under greenhouse conditions, the best control was observed in plants treated with 60 µg mL−1 of PCA, which reduced ASR severity and lesion frequency by 75% and 43%, respectively. Plants sprayed with 2 and 20 µg mL−1 of F4A also decreased severity (41%) and lesion frequency (32%). The significant reduction in spore germination ASR in plant suggested that the strain of these metabolites are effective against P. pachyrhizi, and they can be used for ASR control.

The increasing emergence of multidrug-resistant (MDR) organisms in hospital infections is causing a global public health crisis. The development of drugs with effective antibiotic action against such agents is of the highest priority. In the present study, the action of Fluopsin C against MDR clinical isolates was evaluated under in vitro and in vivo conditions. Fluopsin C was produced in cell suspension culture of Pseudomonas aeruginosa LV strain, purified by liquid adsorption chromatography and identified by mass spectrometric analysis. Bioactivity, bacterial resistance development risk against clinically important pathogenic strains and toxicity in mammalian cell were initially determined by in vitro models. In vivo toxicity was evaluated in Tenebrio molitor larvae and mice. The therapeutic efficacy of intravenous Fluopsin C administration was evaluated in a murine model of Klebsiella pneumoniae (KPC) acute sepsis, using six different treatments. The in vitro results indicated MIC and MBC below 2 μg/mL and low bacterial resistance development frequency. Electron microscopy showed that Fluopsin C may have altered the exopolysaccharide matrix and caused disruption of the cell wall of MDR bacteria. Best therapeutic results were achieved in mice treated with a single dose of 2 mg/kg and in mice treated with two doses of 1 mg/kg, 8 h apart. Furthermore, acute and chronic histopathological studies demonstrated absent nephrotoxicity and moderate hepatotoxicity. The results demonstrated the efficacy of Fluopsin C against MDR organisms in in vitro and in vivo models, and hence it can be a novel therapeutic agent for the control of severe MDR infections.

The objective of this work was to evaluate the effect of the chemical and biological fertilizing on the development of two varieties of Schizolobium parahyba, paricá and guapuruvú. The chemical fertilizer NPK 20-05-20 and the plant growth promoting microorganisms, Rhizobium sp. (Rhi) and Rhizophagus clarus (Arbuscular Mycorrhizal Fungus - AMF). The experimental design was a randomized complete block with five replicates and eight treatments. Forty-six day old seedlings of each variety were planted in pits containing hydroretent gel. Then the treatments were added: 1. Control; 2. Rhi; 3. AMF; 4. NPK; 5. Rhi + NPK; 6. Rhi + AMF; 7. AMF + NPK; 8. Rhi + AMF + NPK. Plant length, stem diameter and survival in the environment were evaluated. The ANOVA followed by the Duncan test (? = 0,05) was used to compare the means of the treatments. In the four evaluated periods (37, 111, 250 and 360 days), both varieties had a positive effect on height, diameter and survival when applied to NPK treatments. The interaction AMF and Rhizobium sp. favored the growth in diameter of the guapuruvú. For paricá variety that same treatment provided higher growth in height, however, AMF impaired development in diameter of this variety. Thus, it was observed that under low fertility conditions, the interaction AMF + Rhi favored a greater resistance of guapuruvú to abiotic stress compared to treatment 3, and the presence of grasses in the experimental area may have contributed to the reduction on the development of S. parahyba.

In this work, the metabolic elicitors extracted from the beneficial rhizobacterium Pseudomonas fluorescens N 21.4 were sequentially fragmented by vacuum liquid chromatography to isolate, purify and identify the compounds responsible for the extraordinary capacities of this strain to induce systemic resistance and to elicit secondary defensive metabolism in diverse plant species. To check if the fractions sequentially obtained were able to increase the synthesis of isoflavones and if, therefore, they still maintained the eliciting capacity of the live strain, rapid and controlled experiments were done with soybean seeds. The optimal action concentration of the fractions was established and all of them elicited isoflavone secondary metabolism—the fractions that had been extracted with n-hexane being more effective. The purest fraction was the one with the highest eliciting capacity and was also tested in Arabidopsis thaliana seedlings to induce systemic resistance against the pathogen Pseudomonas syringae pv. tomato DC 3000. This fraction was then analyzed by UHPLC/ESI–QTOF–MS, and an alkaloid, two amino lipids, three arylalkylamines and a terpenoid were tentatively identified. These identified compounds could be part of commercial plant inoculants of biological and sustainable origin to be applied in crops, due to their potential to enhance the plant immune response and since many of them have putative antibiotic and/or antifungal potential.

ABSTRACTSchizolobium parahyba pv. amazonicum (Huber ex Ducke) Barneby (paricá) occurs naturally in the Amazon and is significant commercial importance due to its rapid growth and excellent performance on cropping systems. The aim of this paper was to evaluate a microbial inoculants such as arbuscular mycorrhiza fungi (AMF) and Rhizobium sp. that promote plant growth. The inocula was 10 g of root colonized and spores of Glomus clarum and/or 1 mL of cell suspension (107 CFU/mL) of Rhizobium sp. and/or 100 g of chemical fertilizer NPK 20-05-20 per planting hole. The experimental design was complete randomized blocks with five replications and eight treatments (n = 800). Plant height, stem diameter and plant survival were measured. The results were tested for normality and homogeneity of variances and analyzed by ANOVA and Tukey test (p < 0.05). Rhizobium sp and AM fungi showed no effect on plant growth. Environmental factors probably influenced the effectiveness of symbiosis of both microorganisms and plant growth. The chemical fertilizer increased S. parahyba growth. During the first 120 days plants suffered with drought and frost, and at 180 days plants inoculated with microorganism plus chemical fertilizer showed higher survival when compared with control. The results showed that the microbial inoculants used showed an important role on plant survival after high stress conditions, but not in plant growth. Also was concluded that the planting time should be between November to December to avoid the presence of young plants during winter time that is dry and cold.

Pasture degradation is a concern, especially in susceptible sandy soils for which strategies to recover them must be developed. Microbiological and biochemical soil health indicators are useful in the guindace of soil management practices and sustainable soil use. We assessed the success of threePanicum maximum Jacq. cultivars in the reclamation of a pasture in a sandy Typic Acrudox in the northwest of the state of Paraná, Brazil, based on soil health indicators. On a formerly degraded pasture withUrochloa brizantha (Hochst. ex A. Rich.) R.D. Webster, a trial with threeP. maximum (cv. Massai, Tanzânia, or Mombaça) was conducted. Lime and phosphate were applied at set-up, and mineral N and K as topdressing. A remnant of degraded pasture adjacent to the trial was used as control. Twenty-three chemical, physical, microbiological and biochemical attributes were assessed for the 0-10 cm topsoil. The procedures for reclamation improved most of the indicators of soil health in relation to the degraded pasture, such as soil P, mineral N, microbial biomass C, ammonification rate, dehydrogenase activity and acid phosphatase. CO2 evolution decreased, whereas microbial biomass C increased in the pasture under reclamation, resulting in a lower metabolic quotient (qCO2) that points to a decrease in metabolic stress of the microbial community. The reclamation of the pasture withP. maximum, especially cv. Mombaça, were evidenced by improvements in the microbiological and biochemical soil health indicators, showing a recovery of processes related to C, N and P cycling in the soil.

La infección relacionada con la atención sanitaria es una de las principales causas de morbimortalidad entre los pacientes hospitalizados. El objetivo de este estudio epidemiológico fue determinar la mortalidad y los riesgos asociados con el fallecimiento de pacientes adultos con la infección relacionada con la atención sanitaria ingresados en un hospital universitario en el periodo de un año. Los datos de los pacientes se obtuvieron de registros de notificación de infecciones. La tasa de mortalidad asociada con las infecciones fue del 38,4%, y fueron clasificados como un factor que contribuye en el 87,1% de las muertes. La asociación de la infección relacionada con la atención sanitaria con el fallecimiento fue estadísticamente significativa entre pacientes clínicos (41,3%), que presentaron comorbilidad asociadas a el diagnóstico (55,8%), con infección cardiovascular (62,2%), neumonía (48,9%), que desarrollaron sepsis (69,0%), colonizados (45,2%) o infectados (44,7%) por microorganismos multirresistentes. Se concluyó que las infecciones contribuyeron a la muerte de la mayoría de los pacientes.

The bacterial resistance for antibiotics is one of the most important problems in public health and only a small number of new products are in development. Antagonistic microorganisms from soil are a promising source of new candidate molecules. Products of secondary metabolism confer adaptive advantages for their producer, in the competition for nutrients in the microbial community. The biosynthesis process of compounds with antibiotic activity is the key to optimize their production and the transcriptomic study of microorganisms is of great benefit for the discovery of these metabolic pathways. Pseudomonas aeruginosa LV strain growing in the presence of copper chloride produces a bioactive organometallic compound, which has a potent antimicrobial activity against various microorganisms. The objective of this study was to verify overexpressed genes and evaluate their relation to the organometallic biosynthesis in this microorganism. P. aeruginosa LV strain was cultured in presence and absence of copper chloride. Two methods were used for transcriptomic analysis, genome reference-guided assembly and de novo assembly. The genome referenced analysis identified nine upregulated genes when bacteria were exposed to copper chloride, while the De Novo Assembly identified 12 upregulated genes. Nineteen genes can be related to an increased microbial metabolism for the extrusion process of exceeding intracellular copper. Two important genes are related to the biosynthesis of phenazine and tetrapyrroles compounds, which can be involved in the bioremediation of intracellular copper and we suggesting that may involve in the biosynthesis of the organometallic compound. Additional studies are being carried out to further prove the function of the described genes and relate them to the biosynthetic pathway of the organometallic compound.

One of the most important postharvest plant pathogens that affect strawberries, grapes and tomatoes is Botrytis cinerea, known as gray mold. The fungus remains in latent form until spore germination conditions are good, making infection control difficult, causing great losses in the whole production chain. This study aimed to purify and identify phenazine-1-carboxylic acid (PCA) produced by the Pseudomonas aeruginosa LV strain and to determine its antifungal activity against B. cinerea. The compounds produced were extracted with dichloromethane and passed through a chromatographic process. The purity level of PCA was determined by reversed-phase high-performance liquid chromatography semi-preparative. The structure of PCA was confirmed by nuclear magnetic resonance and electrospray ionization mass spectrometry. Antifungal activity was determined by the dry paper disk and minimum inhibitory concentration (MIC) methods and identified by scanning electron microscopy and confocal microscopy. The results showed that PCA inhibited mycelial growth, where MIC was 25 μg mL-1. Microscopic analysis revealed a reduction in exopolysaccharide (EPS) formation, showing distorted and damaged hyphae of B. cinerea. The results suggested that PCA has a high potential in the control of B. cinerea and inhibition of EPS (important virulence factor). This natural compound is a potential alternative to postharvest control of gray mold disease.

This study evaluated the antibiotic activity and induction of resistance in plants by compounds produced by Pseudomonas aeruginosa LV strain on the control of bacterial stem rot in tomato. Compounds were extracted from the cell-free supernatant of a bacterial culture and purified. The F4A fraction was composed of two major compounds, an antibiotic and a phenazine (PCN). The first experiment evaluated the antibiotic activity of F4A, and the second one compared the ability of F4A and PCN to elicit systemic acquired resistance (SAR). In both experiments, plants were infected with Pectobacterium carotovorum subsp. carotovorum (Pcc). The minimum inhibitory concentration of F4A was 7.81 μg mL−1, and PCN did not inhibit bacterial growth. The results suggest that F4A has antibiotic activity. Scanning electron microscopy revealed changes in bacterial cells after 3 h treatment with F4A. F4A and PCN decreased symptoms of stem rot and increased fruit production. Plant response was estimated by determination of peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase activity. Plants treated with PCN or F4A showed greater enzyme activity than plants that were not treated or treated with Bion®, suggesting that PCN increased SAR. The compounds showed the potential to control Pcc in vitro and in vivo and to induce plant response.

Sustainable use of soil, maintaining or improving its quality, is one of the goals of diversification in farmlands. From this point of view, bioindicators associated with C, N and P cycling can be used in assessments of land-use effects on soil quality. The aim of this study was to investigate chemical, microbiological and biochemical properties of soil associated with C, N and P under different land uses in a farm property with diversified activity in northern Parana, Brazil. Seven areas under different land uses were assessed: fragment of native Atlantic Forest; growing of peach-palm (Bactrys gasipaes); sugarcane ratoon (Saccharum officinarum) recently harvested, under renewal; growing of coffee (Coffea arabica) intercropped with tree species; recent reforestation (1 year) with native tree species, previously under annual crops; annual crops under no-tillage, rye (Cecale cereale); secondary forest, regenerated after abandonment (for 20 years) of an avocado (Persea americana) orchard. The soil under coffee, recent reforestation and secondary forest showed higher concentrations of organic carbon, but microbial biomass and enzyme activities were higher in soils under native forest and secondary forest, which also showed the lowest metabolic coefficient, followed by the peach-palm area. The lowest content of water-dispersible clay was found in the soil under native forest, differing from soils under sugarcane and secondary forest. Soil cover and soil use affected total organic C contents and soil enzyme and microbial activities, such that more intensive agricultural uses had deeper impacts on the indicators assessed. Calculation of the mean soil quality index showed that the secondary forest was closest to the fragment of native forest, followed by the peach-palm area, coffee-growing area, annual crop area, the area of recent reforestation and the sugarcane ratoon area.

Schizolobium parahyba var. amazonicum (Huber ex Ducke) occurs naturally in the Brazilian Amazon. Currently, it is being planted extensively because of its fast growth and excellent use in forestry. Consequently, there is great interest in new strategies to increase wood production. The interaction between soil microorganisms and plants, specifically in the roots, provides essential nutrients for plant growth. These interactions can have growth-promoting effects. In this way, this study assessed the effect of the inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on growth of S. parahyba var. amazonicum under field conditions. We used two native species of arbuscular mycorrhizal fungi, Claroideoglomus etunicatum (Ce) and Acaulospora sp. (Ac); two native strains of Rhizobium sp. (Rh1 and Rh2); and a non-native strain of Burkholderia sp. Different combinations of microorganisms were supplemented with chemical fertilizers (doses D1 and D2) in two planting methods, seed sowing and seedling planting. In seed sowing, the results showed that treatments with Ce/Rh1/Fertilizer D2 and Ac/No PGPR/Fertilizer D2 increased wood yield. In seedling planting, two combinations (Ac/Rh2/Fertilizer D1 and Ac/Rh1/Fertilizer D1) were more effective in increasing seedling growth. In these experiments, inoculation with AMF and PGPR increased wood yield by about 20% compared to the application of fertilizer alone.

Some diazotrophic bacteria can fix nitrogen biologically in gramineous host plants. Generally, gramineous plants are also associated with mycorrhizal fungi, that can improve mainly plant P uptake. Among the factors affecting plant-microbe interactions, the plant genotype plays an important role. This study evaluates the effect of diazotrophic bacteria and an arbuscular mycorrhizal fungus (AMF), on five genotypes of maize (Zea mays L.), in relation to plant biomass, shoot N and P concentrations, and fine root morphological traits. The experimental design was entirely randomized in a factorial 5 × 4 × 2 arrangement, i.e., five maize genotypes (hybrids C333B, AS3466, and PREMIUM, and the inbreed lines lg40897-1 and lg40505-1), three diazotrophic bacteria (Azospirillum lipoferum, A. amazonense, and Burkholderia sp.) in addition to a control without bacterial inoculation, co-inoculated or not with the AMF Glomus clarum. The non-mycorrhizal plants inoculated with Azospirillum exhibited the highest N concentrations. The lines lg40897-1 and lg40505-1 showed higher P concentrations as compared to the hybrids, mainly when colonized by AMF. The higher levels of mycorrhizal colonization (90%) occurred in the C333B and lg40897-1 genotypes, which also exhibited a greater root diameter. Mycorrhiza increased shoot and root biomass, besides root traits as total length, specific length, total surface, and incidence of root hairs in all genotypes. In addition, mycorrhiza also stimulated the root colonization by diazotrophic bacteria. The bacteria did not affect root morphological traits and mycorrhizal colonization.Algumas bactérias diazotróficas podem fixar N biologicamente em gramíneas, as quais se associam a fungos micorrízicos, o que pode levar a um aumento principalmente da absorção de P. Dentre os fatores que afetam as interações planta-microrganismos, o genótipo da planta tem importante papel. Esse trabalho avalia o efeito de bactérias diazotróficas e de um fungo micorrízico arbuscular (FMA) em cinco genótipos de milho (Zea mays L.), em relação à biomassa das plantas, teores de N e P na parte aérea e parâmetros relacionados à morfologia das raízes finas. O delineamento experimental foi inteiramente casualizado, em arranjo fatorial 5 × 4 × 2, sendo cinco genótipos de milho (híbridos C333B, AS3466, PREMIUM e as linhagens lg40897-1 e lg40505-1), três bactérias diazotróficas (Azospirillum lipoferum, A. amazonense e Burkholderia sp.), mais um controle sem bactéria, co-inoculadas ou não com o FMA Glomus clarum. As plantas sem FMA e inoculadas com Azospirillum apresentaram os maiores teores de N. As linhagens lg40897-1 e lg40505-1 apresentaram maior concentração de P em relação aos híbridos, principalmente quando micorrizadas. Os maiores níveis de colonização micorrízica (90%) ocorreram nos genótipos C333B e lg40897-1 que, por sua vez, apresentaram maior diâmetro de raízes. O FMA aumentou a biomassa da parte aérea e das raízes, comprimento total e específico, superfície total e incidência de pêlos nas raízes em todos os genótipos. O fungo micorrízico também estimulou a colonização das raízes pelas bactérias diazotróficas. Já as bactérias não alteraram as características morfológicas das raízes e nem a colonização micorrízica.

The objective of this work was to assess the effect of two strains of Bacillus thuringiensis var. kurstaki on sorghum rhizosphere microorganisms. The strains were HD1, that produces the bioinsecticidal protein, and 407, that is a mutant non-producer. The strains do not influence microbial population, but reduce plant growth and improve mycorrhizal colonization and free living fixing N2 community.O objetivo deste trabalho foi avaliar o efeito de duas cepas de Bacillus thuringiensis var. kurstaki sobre microrganismos na rizosfera do sorgo. As cepas foram a HD1, produtora do cristal bioinseticida, e a 407, uma mutante não-produtora. As duas cepas não influenciam a comunidade microbiana, mas reduzem o crescimento da planta. A colonização micorrízica e a população de fixadores de N2 de vida livre aumentaram.

In tropical countries such as Brazil, there is not enough information about microbial contaminants in indoor environments with air conditioning systems. Microbial monitoring of such environments is important for the quality of human life. The aim of this work was to assess the fungal genera and bacterial morphotypes occurring in such environments. Air samples were taken indoors and outdoors from a public auditorium, a hospital, a company and a shopping center during the 2001 winter by using a six-stage impactor Millipore M air T® . Twenty-one fungal genera were identified. Bacterial morphological groups found were Gram positive and negative rods and Gram positive coccus.Em países tropicais como o Brasil, não há informação suficiente sobre contaminantes microbianos em ambientes internos com sistemas de ar condicionado. Monitoramento microbiano em tais ambientes é importante para a qualidade de vida humana. O objetivo deste trabalho foi identificar os gêneros de fungos e morfotipos de bactérias que ocorrem em tais ambientes. Amostras de ar foram coletadas dentro e fora de um auditório público, um hospital, uma empresa e um shopping center durante o inverno de 2001 utilizando um impactador de ar de seis estágios Millipore M air T® . Vinte e um gêneros de fungos foram identificados. Foram encontrados grupos morfológicos de bactérias bastonetes Gram positivos e negativos e cocos Gram positivos.

We studied the microhabitats and the climatic requirements of six Drosera taxa, which occur in the subtropical grasslands of the Tibagi river basin. They are annual,or most communly, perennial herbs known as carnivorous plants, whose leaves are transformed into traps for the capture and digestion of small insects as an adaptation for supplying nutricional deficiencies. They usually occur in distrophic substrata. In order to contribute to conservation plans for the species of the genus, threatened by the conversion of the natural grasslands into pastures, we tried to define their preferential habitats and climatic requirements. We verified that the variables of microhabitat and altitude presented significant correlation at 5% probability level, while the variables in annual average relative humidity, annual average temperature and type of substratum types did not show significant correlation.Nós estudamos os microhabitats e as exigências climáticas de seis taxa de Drosera (Droseraceae), que ocorrem nos campos subtropicais da bacia do rio Tibagi. São ervas perenes, conhecidas como plantas carnívoras, cujas folhas são transformadas em armadilhas para a captura e digestão de pequenos animais, o que tem sido referido como adaptação para suprir deficiências nutricionais, já que geralmente ocorrem em substratos distróficos. Para auxiliar na elaboração de planos de conservação para as espécies do gênero, ameaçadas pela conversão dos campos em pastagens, nós procuramos definir os habitats preferenciais e as exigências climáticas. Verificou-se que as variáveis: tipo de microhabitat e altitude apresentam correlação significativa no nível de 5%, enquanto as variáveis: umidade relativa média anual, temperatura média anual e tipo de substrato, não apresentaram correlação significativa. Os resultados obtidos sugerem que a distribuição dos taxa de Drosera estudados está relacionada principalmente com a variação de altitude e o tipo de microhabitat.

Quatro isolados bacterianos da rizosfera de Drosera villosa var. villosa (B1, B2, B3, B4) e dois isolados de Bacillus thuringiensis (B5 e B6), sendo B6 produtor da toxina bioinseticida Cry1Ab, foram avaliados quanto à capacidade de inibir os fungos fitopatogênicos Fusarium solani f. sp. phaseoli, Fusarium solani f. sp. glycines, Fusarium oxysporum e Colletotrichum sp. A cepa mais efetiva foi B1 que inibiu o crescimento dos quatro fungos até o 26º dia. B. thuringiensis inibiu o crescimento de três destes, o que indica que possui atividade antifúngica e abre um novo campo de estudo para a utilização do B. thuringiensis.

O presente trabalho constrói uma discussão teórica sobre as interações ambientais, através da influência de microrganismos na nutrição de plantas. Aspectos gerais do ecossistema, no ponto de vista da ecologia, são discutidos tentando manter a compreensão ecológica de muitos processos interativos, que são realizados entre plantas e a superfície do solo. O objetivo foi contribuir para construção do conhecimento de uma questão multidisciplinar, para conscientização da importância das potencialidades e fragilidades dessas interações, tentando manter os limites dessas relações, devido há alta complexidade e amplitude desses processos.