In situ short-term responses of Amazonian understory plants to elevated CO2.

The response of plants to increasing atmospheric CO2 depends on the ecological context where the plants are found. Several experiments with elevated CO2 (eCO2) have been done worldwide, but the Amazonian forest understory has been neglected. As the central Amazon is limited by light and phosphorus, understanding how understory responds to eCO2 is important for foreseeing how the forest will function in the future. In the understory of a natural forest in the Central Amazon, we installed four open-top chambers as control replicates and another four under eCO2 (+250 ppm above ambient levels). Under eCO2, we observed increases in carbon assimilation rate (67%), maximum electron transport rate (19%), quantum yield (56%), and water use efficiency (78%). We also detected an increase in leaf area (51%) and stem diameter increment (65%). Central Amazon understory responded positively to eCO2 by increasing their ability to capture and use light and the extra primary productivity was allocated to supporting more leaf and conducting tissues. The increment in leaf area while maintaining transpiration rates suggests that the understory will increase its contribution to evapotranspiration. Therefore, this forest might be less resistant in the future to extreme drought, as no reduction in transpiration rates were detected.

Direct evidence for phosphorus limitation on Amazon forest productivity.

The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change.

Convergence in phosphorus constraints to photosynthesis in forests around the world.

Tropical forests take up more carbon (C) from the atmosphere per annum by photosynthesis than any other type of vegetation. Phosphorus (P) limitations to C uptake are paramount for tropical and subtropical forests around the globe. Yet the generality of photosynthesis-P relationships underlying these limitations are in question, and hence are not represented well in terrestrial biosphere models. Here we demonstrate the dependence of photosynthesis and underlying processes on both leaf N and P concentrations. The regulation of photosynthetic capacity by P was similar across four continents. Implementing P constraints in the ORCHIDEE-CNP model, gross photosynthesis was reduced by 36% across the tropics and subtropics relative to traditional N constraints and unlimiting leaf P. Our results provide a quantitative relationship for the P dependence for photosynthesis for the front-end of global terrestrial C models that is consistent with canopy leaf measurements.

Tracking and plant growth-promoting effect of Paraburkholderia tropica MTo-293 applied to Solanum lycopersicum.

Paraburkholderia tropica MTo-293 was applied as an experimental bio-input to Solanum lycopersicum (tomato) cv. Platense. Different plant growth systems and inoculation strategies were tested to evaluate P. tropica plant colonization at the seedling stage (growth chamber) using culture-dependent and -independent techniques. The effect of P. tropica on plant growth was evaluated in the growth chamber and greenhouse (productive stage) by biomass accumulation and fruit production, respectively. P. tropica was able to colonize the surface and inner root and stem of tomato seedlings regardless of the inoculation strategy-at sowing and/or before transplanting-showing the competitive nature of P. tropica in nonsterile substrate systems. A nested polymerase chain reaction was validated to track P. tropica in tomato plants even in the inner stem with endophytic P. tropica populations of less than 102 CFU g-1 of fresh weight. Efficient colonization of P. tropica correlated with a positive effect on tomato growth when applied at sowing and/or before transplanting: plant growth promotion was observed not only at the seedling stage but also at productive stages improving crop yield in two different seasons. To our knowledge, this report is the first to track and evaluate the plant growth-promoting effect of P. tropica MTo-293 in tomato plants grown in nonsterile substrate systems.

Southeast Alaskan kelp forests: inferences of process from large-scale patterns of variation in space and time.

Humans were considered external drivers in much foundational ecological research. A recognition that humans are embedded in the complex interaction networks we study can provide new insight into our ecological paradigms. Here, we use time-series data spanning three decades to explore the effects of human harvesting on otter-urchin-kelp trophic cascades in southeast Alaska. These effects were inferred from variation in sea urchin and kelp abundance following the post fur trade repatriation of otters and a subsequent localized reduction of otters by human harvest in one location. In an example of a classic trophic cascade, otter repatriation was followed by a 99% reduction in urchin biomass density and a greater than 99% increase in kelp density region wide. Recent spatially concentrated harvesting of otters was associated with a localized 70% decline in otter abundance in one location, with urchins increasing and kelps declining in accordance with the spatial pattern of otter occupancy within that region. While the otter-urchin-kelp trophic cascade has been associated with alternative community states at the regional scale, this research highlights how small-scale variability in otter occupancy, ostensibly due to spatial variability in harvesting or the risk landscape for otters, can result in within-region patchiness in these community states.

Changes in leaf functional traits with leaf age: when do leaves decrease their photosynthetic capacity in Amazonian trees?

Most leaf functional trait studies in the Amazon basin do not consider ontogenetic variations (leaf age), which may influence ecosystem productivity throughout the year. When leaf age is taken into account, it is generally considered discontinuous, and leaves are classified into age categories based on qualitative observations. Here, we quantified age-dependent changes in leaf functional traits such as the maximum carboxylation rate of ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco) (Vcmax), stomatal control (Cgs%), leaf dry mass per area and leaf macronutrient concentrations for nine naturally growing Amazon tropical trees with variable phenological strategies. Leaf ages were assessed by monthly censuses of branch-level leaf demography; we also performed leaf trait measurements accounting for leaf chronological age based on days elapsed since the first inclusion in the leaf demography, not predetermined age classes. At the tree community scale, a nonlinear relationship between Vcmax and leaf age existed: young, developing leaves showed the lowest mean photosynthetic capacity, increasing to a maximum at 45 days and then decreasing gradually with age in both continuous and categorical age group analyses. Maturation times among species and phenological habits differed substantially, from 8 ± 30 to 238 ± 30 days, and the rate of decline of Vcmax varied from -0.003 to -0.065 µmol CO2 m-2 s-1 day-1. Stomatal control increased significantly in young leaves but remained constant after peaking. Mass-based phosphorus and potassium concentrations displayed negative relationships with leaf age, whereas nitrogen did not vary temporally. Differences in life strategies, leaf nutrient concentrations and phenological types, not the leaf age effect alone, may thus be important factors for understanding observed photosynthesis seasonality in Amazonian forests. Furthermore, assigning leaf age categories in diverse tree communities may not be the recommended method for studying carbon uptake seasonality in the Amazon, since the relationship between Vcmax and leaf age could not be confirmed for all trees.

Variation in purple sea urchin (Strongylocentrotus purpuratus) morphological traits in relation to resource availability.

Flexible resource investment is a risk sensitive reproductive strategy where individuals trade resources spent on reproduction for basic metabolic maintenance and survival. This study examined morphological variation in herbivorous sea urchin grazers across a mosaic landscape of macroalgae dominated habitats interspersed with patches of sea urchin barrens to determine whether sea urchins shift energy allocation in response to food limitation. Extensive underwater surveys of habitat attributes (e.g., sea urchin density, algae cover) were paired with detailed laboratory assays (e.g., sea urchin dissections) to determine how resource abundance affects energy allocation between reproductive capacity and body structure in the purple sea urchin, Strongylocentrotus purpuratus. We found that: (1) sea urchins had a more elongate jaw structure relative to body size in habitats void of macroalgae (i.e., barrens), (2) sea urchin reproductive capacity (i.e., gonad index) was lower in barrens and the barrens habitat was primarily comprised of encrusting algae, and (3) sea urchin jaw morphology (i.e., lantern index) and reproductive capacity (i.e., gonad index) were inversely related. These results suggest that sea urchins respond to macroalgae limited environments by shifting energy allocation between reproductive capacity and modifications of the foraging apparatus, which may explain the ability of sea urchins to acquire food in resource-limited environments.

Bundle para a prevenção de lesões por pressão relacionadas a dispositivos médicos em pacientes críticos / Bundle for the prevention of pressure injuries related to medical devices in critically ill patients

Introdução: O paciente grave necessita de suporte avançado, instituído através de dispositivos médicos, podendo desenvolver Lesões por Pressão Relacionadas a Dispositivos Médicos. Essas lesões são comuns nos ambientes de saúde, necessitando atenção, principalmente pelas implicações ao paciente.Justifica-se este estudo relacionado aalta incidência e prevalência de destas lesões nos pacientes críticos; agravamento do problema frente a condição pandêmica atual; e que os dispositivos médicos são indispensáveis no contexto da Unidade de Terapia Intensiva. Objetivo: Elaborar e validar bundle para prevenção de lesões por pressão relacionados a dispositivos médicos em pacientes adultos em situação crítica de vida.Métodos:Utilizou-se a Técnica de Delphi, que envolve análise de itens por juízes experientes. O estudo foi estruturado em quatro etapas: Composiçãodo comitê de expertises; Elaboração do bundle; Validação do conteúdo e de aparência; e Índice de validação do conteúdo e de aparência. Utilizou-se o Statistical Package for Social Science 20.0 para cálculo. Resultados: Desenvolveu-se bundle a partir de 21cuidados elencados pelos expertises. Foi possível identificar que o tubo orotraqueal, cateteres e máscaras de ventilação não invasivas, foram os dispositivos médicos que mais causaram lesões. O índice de validação geral de validação do bundle foi de 91,83%.Conclusão: Espera-se que o bundle contribua diminuindo a incidência dessas lesões e elevando a qualidade dos serviços. Além, que o bundle seja utilizado como ferramenta de ensino e orientação do cuidado, tratando-se de material digital de fácil acesso,podendo ser compartilhado com a equipe.

Introduction: The critically ill patient needs advanced support, instituted through medical devices, and may develop Medical Device Related Pressure Injuries. These injuries are common in healthcare settings, and require attention because of the implications to the patient. This is justified by the high incidence and prevalence of these injuries in critically ill patients, the aggravation of the problem in the face of the pandemic, and the fact that medical devices are indispensable in the context of the Intensive Care Unit. Objective: To develop and validate a set of measures for the prevention of medical device-related pressure injuries in critically ill adult patients.Methods: The Delphi technique was used, analysis by expert judges. It was structured in four stages: Composition of the expert committee; Preparation of the package; Validation of content and appearance; and Validation index of content and appearance. The Statistical Package for the Social Sciences 20.0 was used for the calculation.Results: A package was developed from 21 care. The orotracheal tube, catheters, and noninvasive ventilation masks were identified as causing the most injury. The overall validation rate of the package was 91.83%.Conclusion: It is expected that the package will contribute to reducing the incidence of these injuries by increasing the quality of services. In addition, it should be used as a tool for teaching and guidance, as it is a digital material that is easily accessible and can be shared with the team.

Occurrence and bioacessibility of mycotoxins in fish feed.

In this study Aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEN) occurrence in fish feed, regarding its chemical composition, were investigated. Besides, AFB1 bioaccessibility to fish was evaluated by in vitro digestion. Mycotoxins were extracted by QuEChERS and quantified by HPLC-FLD. Results showed that 93.3% of the samples were contaminated at maximum levels of 16.5, 31.6, and 322 µg/kg in the cases of AFB1, OTA, and ZEN, respectively. A positive correlation between OTA, ZEN contamination, and lipid content was observed. Risk estimation of feed consumption by fish at the highest levels of AFB1, OTA, and ZEN shows that the younger the fish, the higher the risk of exposure to mycotoxins. The AFB1 bioaccessibility assay showed that 85% of this mycotoxin may be absorbed by fish. Therefore, establishing maximum levels in the fishing sector is fundamental to contribute to feed quality and nutritional safety of fish species.

Comparison between Allura Red dye discoloration by activated carbon and azo bacteria strain.

Azo dyes are extensively used in different industries areas, such as Allura Red (R-40). Previous studies have proven its carcinogenic and mutagenic properties. For the removal of this type of emerging pollutant from effluents, tertiary treatment techniques such as activated charcoal are used. Alternatively, the use of bacteria is preferred because of its quick discoloration processes. The aim of the present investigation is to compare the efficiency removal of R-40 from aqueous media by a physicochemical process and a biological one. The sorption kinetics of 10 ppm of R-40 was carried out with the use of activated charcoal based on walnut shells in water. Moreover, Pseudomonas aeruginosa and Bacillus subtilis stains were used separately to decolorize nutrient broth media supplemented with 50 ppm of R-40. The activated carbon was capable to remove 99.87% of R-40 at 264 h, while the bacterial strains decolorized 92.13% (P. aeruginosa) and 88.21% (B. subtilis), respectively, under microaerophilic conditions after 168 h. Therefore, both process strategies, physicochemical and biological rapprochements, were able to remove the dye from aqueous media. R-40 was not cytotoxic to used strains, besides gram-positive either negative bacteria could be applied to turn over this azo dye in short term. Combination of both approaches may be implemented in tandem architecture.

Peroxidase as a simultaneous degradation agent of ochratoxin A and zearalenone applied to model solution and beer.

The aim of this study was to evaluate the action of the commercial peroxidase (POD) enzyme (Armoracia rusticana) on the simultaneous degradation of ochratoxin A (OTA) and zearalenone (ZEA) in model solution and beer. For this purpose, the reaction parameters for POD action were optimized, POD application in the degradation of mycotoxins in model solution and beer was evaluated and the kinetic parameters of POD were defined (Michaelis-Menten constant - KM and maximal velocity - Vmax). In the reaction conditions (pH 7, ionic strength of 25 mM, incubation at 30 °C, addition of 26 mM H2O2 and 1 mM potassium ion), POD (0.6 U mL-1) presented the maximum activity for simultaneous degradation of OTA and ZEA of 27.0 and 64.9%, respectively, in model solution after 360 min. The application of POD in beer resulted in the simultaneous degradation of OTA and ZEA of 4.8 and 10.9%, respectively. The kinetic parameters KM and Vmax for degradation of OTA and ZEA were 50 and 10,710 nM and 0.168 and 72 nM min-1, respectively. Therefore, POD can be a promising alternative to mitigate the contamination of OTA and ZEA in model solution and beer, minimizing their effects in humans.

Sources, quantification techniques, associated hazards, and control measures of mycotoxin contamination of aquafeed.

With the productive intensification of fish farming, the partial or total replacement of fishmeal by ingredients of plant origin became a reality within the feed industry, with the aim of reducing costs. However, this practice increased the impact of mycotoxin contamination. Studies have shown that mycotoxins can induce various disorders in fish, such as cellular and organic alterations, as well as impair functional and morphological development, and, in more severe cases, mortality. Thus, studies have been conducted to evaluate and develop strategies to prevent the formation of mycotoxins, as well as to induce their elimination, inactivation or reduction of their availability in feed.

Correction: Influence of co-cultures of Streptococcus thermophilus and probiotic lactobacilli on quality and antioxidant capacity parameters of lactose-free fermented dairy beverages containing Syzygium cumini (L.) Skeels pulp.

[This corrects the article DOI: 10.1039/C9RA08311A.].

Influence of co-cultures of Streptococcus thermophilus and probiotic lactobacilli on quality and antioxidant capacity parameters of lactose-free fermented dairy beverages containing Syzygium cumini (L.) Skeels pulp.

This study investigated the influence of probiotic lactobacilli in co-culture with Streptococcus thermophilus on composition, physicochemical parameters, microbial viability, sensory acceptability, antioxidant capacity and protein profile of lactose-free fermented dairy beverages with added whey, ß-galactosidase and jambolan (Syzygium cumini (L.) Skeels) pulp. Three beverages (T1, T2 and T3) were prepared with Streptococcus thermophilus TA-40 as starter culture. Lactobacillus rhamnosus LR32 and Lactobacillus casei BGP93 probiotic cultures were added into T2 and T3, respectively. The probiotic adjuvants slightly influenced the pH and titratable acidity of dairy beverages, with no influence on the proximate composition and on the sensory attributes. Samples presented fat and protein contents suitable to meet the requirements of "low-fat dairy beverages with non-dairy ingredients added" according to the Brazilian legislation, lactobacilli viability above 7 log CFU g-1 for both probiotics and total phenolic content around 40 mg GAE 100 g-1. Colour was the most evaluated sensory aspect (average scores close or higher than 8 in a scale from 0 to 10 for most of the sampling periods). The overall antioxidant capacity increased significantly following the addition of jambolan (p < 0.05), and significantly more during storage (p < 0.05), likely due to proteolysis verified in the electrophoresis gels, as a result of the metabolism of the lactic cultures. The dairy beverages studied are good options for functional foods due to their nutritional value, viability of probiotic lactobacilli, phenolic content, and antioxidant capacity, also serving lactose-intolerant people.

Inhibition of in vitro trichothecenes production by microalgae phenolic extracts.

There is evidence that microalgae phenolic compounds can inhibit the growth of toxigenic fungi. This study aimed to evaluate the ability of microalgae phenolic extracts to inhibit trichothecene production by Fusarium genus and thereby identify parameters that can promote a new technology to avoid contamination of crops by mycotoxins. The microalgae phenolic acids (Spirulina sp. and Nannochloropsis sp.) were extracted with methanol, clarified and resuspended in water. The in vitro experiment involved adding the phenolic extract from each microalga (40 µg/mL) to Petri dishes containing culture medium and previously sterilized wheat grains, with subsequent inoculation of an isolate belonging to the F. graminearum species complex. The control was cultured with sterile water. Treatment with the fungicide tebuconazole (0.6 mg/mL) was also performed. Petri dishes were incubated at 25 °C, with a light/dark photoperiod of 12-12 h. After 168 h, the samples were extracted by the adapted QuEChERS method; the trichothecenes (nivalenol, deoxynivalenol and acetylates) were identified and quantified by high-performance liquid chromatography. When the phenolic extracts from microalgae were applied, the characteristic peak of nivalenol was not detected, suggesting total inhibition, whereas, the nivalenol content increased (15%) in the presence of tebuconazole. Both microalgae phenolic extracts also had a promising effect on the inhibition of deoxynivalenol, with no detection (Nannochloropsis sp. extract) and 62% reduction (Spirulina sp. extract). The application of the fungicide tebuconazole increased the deoxynivalenol concentration. Both microalgae phenolic extracts and tebuconazole decreased the detection of acetylates. Thus, phenolic extracts from microalgae were more efficient than tebuconazole as antifungal and antimycotoxigenic agents in cultures in vitro.

Aflatoxin M1 and B1 in Colombian milk powder and estimated risk exposure.

Aflatoxin M1 (AFM1) and aflatoxin B1 (AFB1) were determined in 51 milk powder samples purchased from different grocery stores located in the Caribbean region of Colombia. Analysis was conducted using QuEChERS extraction and high-performance liquid chromatography with fluorescence detection. Results from the analytical method showed recovery ranges from 65% to 110% and relative standard deviations lower than 20%. AFM1 was detected in 100% of the milk samples (0.20-1.19 µg/kg) and 55% exceeded the maximum level in milk (0.5 µg/kg) set by the Colombian and European regulations. AFB1 was not detected in any of the analysed samples. Considering the measured contamination the maximum AFM1 level that can be ingested by consumption of milk powder is 0.007-0.013 µg/person/day. These values are above the average dietary intake estimated in Latin America according to the Joint FAO/WHO Expert Committee, which is 0.0035 µg/person/day.

Embolism resistance drives the distribution of Amazonian rainforest tree species along hydro-topographic gradients.

Species distribution is strongly driven by local and global gradients in water availability but the underlying mechanisms are not clear. Vulnerability to xylem embolism (P50 ) is a key trait that indicates how species cope with drought and might explain plant distribution patterns across environmental gradients. Here we address its role on species sorting along a hydro-topographical gradient in a central Amazonian rainforest and examine its variance at the community scale. We measured P50 for 28 tree species, soil properties and estimated the hydrological niche of each species using an indicator of distance to the water table (HAND). We found a large hydraulic diversity, covering as much as 44% of the global angiosperm variation in P50 . We show that P50 : contributes to species segregation across a hydro-topographic gradient in the Amazon, and thus to species coexistence; is the result of repeated evolutionary adaptation within closely related taxa; is associated with species tolerance to P-poor soils, suggesting the evolution of a stress-tolerance syndrome to nutrients and drought; and is higher for trees in the valleys than uplands. The large observed hydraulic diversity and its association with topography has important implications for modelling and predicting forest and species resilience to climate change.

Zearalenone reduction by commercial peroxidase enzyme and peroxidases from soybean bran and rice bran.

The peroxidase (POD) enzyme, obtained from different sources, has been described in the literature regarding its good results of reduction in concentration or degradation levels of mycotoxins, such as aflatoxin B1, deoxynivalenol and zearalenone (ZEA). This study aimed at evaluating the action of commercial POD and POD from soybean bran (SB) and rice bran (RB) in ZEA reduction in a model solution and the characterisation of the mechanism of enzyme action. POD was extracted from SB and RB in phosphate buffer by orbital agitation. Evaluation of the action of commercial POD and POD from SB and RB in ZEA reduction was carried out in phosphate buffer and aqueous solution, respectively. Parameters of (Michaelis-Menten constant) (KM) and maximal rate (Vmax) were determined in the concentration range from 0.16 to 6 µg mL-1. ZEA reduction was determined and the mechanism of enzyme action was characterised by FTIR and high-pressure liquid chromatography-electrospray tandem mass spectrometry. Commercial POD and POD from RB and SB reduced ZEA concentration by 69.9%, 47.4% and 30.6% in 24 h, respectively. KM values were 39.61 and 8.90 µM, whereas Vmax values were 0.170 and 0.011 µM min-1 for commercial POD and POD from RB, respectively. The characterisation of the mechanism of enzyme action showed the oxidoreductive action of commercial POD in the mycotoxin. The use of commercial POD and POD from agro-industrial by-products, such as SB and RB, could be a promising alternative for ZEA biodegradation.

Impact on the quality of life of women with breast cancer undergoing chemotherapy in public and private care.

OBJECTIVES: To compare the general quality of life of women with breast cancer undergoing chemotherapy in a public and a private institution. METHODS: Longitudinal observational study including 115 women with breast cancer in an outpatient chemotherapy treatment at two health institutions, one public and one private, in the city of Curitiba (Brazil). The Quality of Life Questionnaire-C30 and the Quality of Life Questionnaire - Breast Cancer Module instruments were applied at three moments of treatment (onset, 40-50 days, and 85-95 days after initiation). RESULTS: Women's global health status was affected in both groups since the first phase of chemotherapy (76.2 points in the private institution and 74.6 points in the public institution, considering 100 points = maximum health). In both groups there was worsening of quality of life over time, which was lower in women in the private institution (second phase = 75.0 and third phase = 74; p=0.47), compared to those in the public institution (second phase = 71.5 and third phase 69.1; p=0.02). Regarding the type of institution, the most committed functions were the emotional and social in the private, and physical and pain in the public. CONCLUSIONS: The global quality of life of women with breast cancer deteriorated as a result of chemotherapy in both institutions, and it was lower in those receiving private care. Nursing should consider the type of institution responsible for women's care in order to provide comprehensive care that considers the functions affected at each phase of treatment.

Assessment of bacterial inoculant formulated with Paraburkholderia tropica to enhance wheat productivity.

Paraburkholderia tropica is an endophytic nitrogen-fixing bacterium isolated from the rhizosphere, rhizoplane, and internal tissues of sugarcane and corn plants in different geographical regions. Other plant-growth-promoting abilities, such as phosphate solubilization and antifungal activity, have also been reported for this bacterium. With an aim at investigating the potential use of P. tropica as an inoculant for improving the performance of wheat crop, in this work we evaluated an experimental inoculant formulated with P. tropica MTo-293 with respect to root colonization, the practical aspects of its application, and the effects under field conditions when applied to wheat seeds. Bacterial colonization was monitored by culture dependent techniques and the wheat yield determined by quantifying the total grain production in two different seasons. Rhizoplane and endophytic colonization in wheat roots was achieved efficiently (on average, 8 and 4 log colony-forming units/g fresh weight, respectively) even at relatively low concentrations of viable bacteria in the inoculum under controlled conditions. P. tropica was compatible with a widely used fungicide, maintained viability for 48 h once applied to seeds, and was also able to colonize wheat roots efficiently. Furthermore, we were able to formulate an inoculant that maintained bacterial viability for relatively long time periods. Preliminary field assays were realized, and even though the average yields values for the inoculated treatments remained above the uninoculated ones, no significant effects of inoculation were detected with or without fertilization. The correct physiologic behavior of P. tropica suggests the necessity to continue with field experiments under different conditions.