| 1. |
- Abreu, Fernanda, et al.
(författare)
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Culture-independent characterization of a novel magnetotactic member affiliated to the Beta class of the Proteobacteria phylum from an acidic lagoon
- 2018
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Ingår i: Environmental Microbiology. - : Wiley/Blackwell. - 1462-2912 .- 1462-2920. ; 20:7, s. 2615-2624
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Tidskriftsartikel (refereegranskat)abstract
- Summary Magnetotactic bacteria (MTB) comprise a group of motile microorganisms common in most mesothermal aquatic habitats with pH values around neutrality. However, during the last two decades, a number of MTB from extreme environments have been characterized including: cultured alkaliphilic strains belonging to the Deltaproteobacteria class of the Proteobacteria phylum; uncultured moderately thermophilic strains belonging to the Nitrospirae phylum; cultured and uncultured moderately halophilic or strongly halotolerant bacteria affiliated with the Deltaproteobacteria and Gammaproteobacteria classes and an uncultured psychrophilic species belonging to the Alphaproteobacteria class. Here, we used culture-independent techniques to characterize MTB from an acidic freshwater lagoon in Brazil (pH ? 4.4). MTB morphotypes found in this acidic lagoon included cocci, rods, spirilla and vibrioid cells. Magnetite (Fe3O4) was the only mineral identified in magnetosomes of these MTB while magnetite magnetosome crystal morphologies within the different MTB cells included cuboctahedral (present in spirilla), elongated prismatic (present in cocci and vibrios) and bullet-shaped (present in rod-shaped cells). Intracellular pH measurements using fluorescent dyes showed that the cytoplasmic pH was close to neutral in most MTB cells and acidic in some intracellular granules. Based on 16S rRNA gene phylogenetic analyses, some of the retrieved gene sequences belonged to the genus Herbaspirillum within the Betaproteobacteria class of the Proteobacteria phylum. Fluorescent in situ hybridization using a Herbaspirillum-specific probe hybridized with vibrioid MTB in magnetically-enriched samples. Transmission electron microscopy of the Herbaspirillum-like MTB revealed the presence of many intracellular granules and a single chain of elongated prismatic magnetite magnetosomes. Diverse populations of MTB have not seemed to have been described in detail in an acid environment. In addition, this is the first report of an MTB phylogenetically affiliated with Betaproteobacteria class.
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| 2. |
- Basso, Marcos Fernando, et al.
(författare)
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Overexpression of a soybean Globin (GmGlb1-1) gene reduces plant susceptibility to Meloidogyne incognita
- 2022
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Ingår i: Planta. - : SPRINGER. - 0032-0935 .- 1432-2048. ; 256:4
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Tidskriftsartikel (refereegranskat)abstract
- Non-symbiotic globin class #1 (Glb1) genes are expressed in different plant organs, have a high affinity for oxygen, and are related to nitric oxide (NO) turnover. Previous studies showed that soybean Glb1 genes are upregulated in soybean plants under flooding conditions. Herein, the GmGlb1-1 gene was identified in soybean as being upregulated in the nematode-resistant genotype PI595099 compared to the nematode-susceptible cultivar BRS133 during plant parasitism by Meloidogyne incognita. The Arabidopsis thaliana and Nicotiana tabacum transgenic lines overexpressing the GmGlb1-1 gene showed reduced susceptibility to M. incognita. Consistently, gall morphology data indicated that pJ2 nematodes that infected the transgenic lines showed developmental alterations and delayed parasitism progress. Although no significant changes in biomass and seed yield were detected, the transgenic lines showed an elongated, etiolation-like growth under well-irrigation, and also developed more axillary roots under flooding conditions. In addition, transgenic lines showed upregulation of some important genes involved in plant defense response to oxidative stress. In agreement, higher hydrogen peroxide accumulation and reduced activity of reactive oxygen species (ROS) detoxification enzymes were also observed in these transgenic lines. Thus, based on our data and previous studies, it was hypothesized that constitutive overexpression of the GmGlb1-1 gene can interfere in the dynamics of ROS production and NO scavenging, enhancing the acquired systemic acclimation to biotic and abiotic stresses, and improving the cellular homeostasis. Therefore, these collective data suggest that ectopic or nematode-induced overexpression, or enhanced expression of the GmGlb1-1 gene using CRISPR/dCas9 offers great potential for application in commercial soybean cultivars aiming to reduce plant susceptibility to M. incognita.
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| 3. |
- Brito de Figueiredo, Maria Clea, et al.
(författare)
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Reducing the impact of irrigated crops on freshwater availability : the case of Brazilian yellow melons
- 2014
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Ingår i: The International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 0948-3349 .- 1614-7502. ; 19:2, s. 437-448
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Tidskriftsartikel (refereegranskat)abstract
- This study quantifies freshwater consumption throughout the life cycle of Brazilian exported yellow melons and assesses the resulting impact on freshwater availability. Results are used to identify improvement options. Moreover, the study explores the further impact of variations in irrigation volume, yield, and production location. The product system boundary encompasses production of seeds, seedlings, and melon plants; melon packing; disposal of solid farm waste; and farm input and melon transportation to European ports. The primary data in the study were collected from farmers in order to quantify freshwater consumption related to packing and to production of seeds, seedlings, and melons. Open-field melon irrigation was also estimated, considering the region's climate and soil characteristics. Estimated and current water consumptions were compared in order to identify impact reduction opportunities. Sensitivity analysis was used to evaluate variations in the impact because of changes in melon field irrigation, yield, and farm location. This study shows that the average impact on freshwater availability of 1 kg of exported Brazilian yellow melons is 135 l H2O-e, with a range from 17 to 224 l H2O-e depending on the growing season's production period. Irrigation during plant production accounts for 98 % of this impact. Current melon field water consumption in the Low Jaguaribe and A double dagger u region is at least 39 % higher than necessary, which affects the quality of fruits and yield. The impact of melon production in other world regions on freshwater availability may range from 0.3 l H2O-e/kg in Costa Rica to 466 l H2O-e/kg in the USA. The impact of temporary crops, such as melons, on water availability should be presented in ranges, instead of as an average, since regional consumptive water and water stress variations occur in different growing season periods. Current and estimated water consumption for irrigation may also be compared in order to identify opportunities to achieve optimization and reduce water availability impact.
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| 4. |
- de Figueiredo, Maria Clea Brito, et al.
(författare)
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The carbon footprint of exported Brazilian yellow melon
- 2013
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 47, s. 404-414
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Tidskriftsartikel (refereegranskat)abstract
- The carbon footprint of food has become important for producers worldwide as consumers and retail companies increasingly base their purchase decisions on carbon footprint labels. In this context, our objectives is to assess the carbon footprint (CF) of Brazilian yellow melon exported from the Low Jaguaribe and Acu region, including an uncertainty assessment, and to evaluate reduction potentials and improvement options. Exporting farms located in this region account for about 99 percent of Brazilian melon exports, mainly to the United Kingdom and the Netherlands. To determine the CF, we followed Life Cycle Assessment, according to ISO standards (14040 and 14044). The results are expressed in kg of CO2-eq/t of exported melon. The production system encompasses processes in the Low Jaguaribe and Acu region (such as seedling, plant production, packing, and disposal of solid wastes from farms), upstream processes (including the production and transportation of inputs, such as seeds, plastics, and fertilizers), and downstream processes (melon transport). The total yellow melon CF in the reference situation is 710 kg CO2-eq/t exported melon. However, scenario results indicate that this value can be reduced by 44 percent if melon fields are located in pre-existing agricultural areas, nitrogen fertilization is reduced, and no plastic field trays are used in melon production. GHG emissions from melon transport are relatively unimportant in the total CF. These results provide melon producers with an insight into the CF of their product, and options to reduce it.
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| 5. |
- Figueiredo, Viviane, et al.
(författare)
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Evolution of nitrogen cycling in regrowing Amazonian rainforest
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Extensive regions of tropical forests are subjected to high rates of deforestation and forest regrowth and both are strongly affect soil nutrient cycling. Nitrogen (N) dynamics changes during forest regrowth and the recovery of forests and functioning similar to pristine conditions depends on sufficient N availability. We show that, in a chronosequence of Amazonian forests, gross nitrification and, as a result, nitrate-to-ammonium (NO3−: NH4+) ratio were lower in all stages of regrowing forests (10 to 40 years) compared to pristine forest. This indicates the evolution of a more conservative and closed N cycle with reduced risk for N leaking out of the ecosystem in regrowing forests. Furthermore, our results indicate that mineralization and nitrification are decoupled in young regrowing forests (10 years), such as that high gross mineralization is accompanied by low gross nitrification, demonstrating a closed N cycle that at the same time maintains N supply for forest regrowth. We conclude that the status of gross nitrification in disturbed soil is a key process to understand the mechanisms of and time needed for tropical forest recovery.
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| 6. |
- Hernandez, Marcela, et al.
(författare)
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Structure, function and resilience to desiccation of methanogenic microbial communities in temporarily inundated soils of the Amazon rainforest (Cunia Reserve, Rondonia)
- 2019
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Ingår i: Environmental Microbiology. - : WILEY. - 1462-2912 .- 1462-2920. ; 21:5, s. 1702-1717
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Tidskriftsartikel (refereegranskat)abstract
- The floodplain of the Amazon River is a large source for the greenhouse gas methane, but the soil microbial communities and processes involved are little known. We studied the structure and function of the methanogenic microbial communities in soils across different inundation regimes in the Cunia Reserve, encompassing nonflooded forest soil (dry forest), occasionally flooded Igapo soils (dry Igapo), long time flooded Igapo soils (wet Igapo) and sediments from Igarape streams (Igarape). We also investigated a Transect (four sites) from the water shoreline into the dry forest. The potential and resilience of the CH4 production process were studied in the original soil samples upon anaerobic incubation and again after artificial desiccation and rewetting. Bacterial and archaeal 16S rRNA genes and methanogenic mcrA were always present in the soils, except in dry forest soils where mcrA increased only upon anaerobic incubation. NMDS analysis showed a clear effect of desiccation and rewetting treatments on both bacterial and archaeal communities. However, the effects of the different sites were less pronounced, with the exception of Igarape. After anaerobic incubation, methanogenic taxa became more abundant among the Archaea, while there was only little change among the Bacteria. Contribution of hydrogenotrophic methanogenesis was usually around 40%. After desiccation and rewetting, we found that Firmicutes, Methanocellales and Methanosarcinaceae became the dominant taxa, but rates and pathways of CH4 production stayed similar. Such change was also observed in soils from the Transects. The results indicate that microbial community structures of Amazonian soils will in general be strongly affected by flooding and drainage events, while differences between specific field sites will be comparatively minor.
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| 7. |
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