Iron deficiency is one of the main causes of chlorosis in plants, which leads to losses in field crops quality and yield. The use of synthetic chelates to prevent or correct iron-deficiency is not ...satisfactory mainly due to their poor biodegradability. The present work aimed to search suitable microorganisms to produce alternative, environment-friendly iron-chelating agents (siderophores). For this purpose, the performance of five bacteria (
Azotobacter vinelandii
,
Bacillus megaterium
,
Bacillus subtilis
,
Pantoea allii
and
Rhizobium radiobacter
) was evaluated, regarding siderophore production kinetics, level of siderophore production (determined by chrome azurol S, CAS method), type of siderophore produced (using Arnow and Csaky’s tests) and iron-chelating capacity at pH 9.0. All bacteria were in stationary phase at 24 h, except
A. vinelandii
(at 72 h) and produced the maximum siderophore amount (80–140 µmol L
−1
) between 24 and 48 h, with the exception of
A. vinelandii
(at 72 h). The analysis of culture filtrates revealed the presence of catechol-type siderophores for
B. subtilis
and
R. radiobacter
and hydroxamate-type siderophores for
B. megaterium
and
P. allii
. In the case of
A. vinelandii
, both siderophore-types (catechol and hydroxamates) were detected. The highest iron-chelating capacity, at pH 9.0, was obtained by
B. megaterium
followed by
B. subtilis
and
A. vinelandii.
Therefore, these three bacteria strains are the most promising bacteria for siderophore production and chlorosis correction under alkaline conditions.
In recent years, research related to the occurrence of marine heatwave (MHW) events worldwide has been increasing, reporting severe impacts on marine ecosystems which led to losses of marine ...biodiversity or changes in world fisheries. Many of these studies, based on regional and global coupled models, show relevant biases in the MHW properties when compared with observations. In this study, the MHW frequency of occurrence, the duration and mean intensity over the global oceans are characterized, taking advantage of the new global climate model (GCM) dataset, from the Coupled Model Project Intercomparison Phase 6 (CMIP6). The MHWs result for the historical period are compared with observations, and the future projected changes are characterized under three socioeconomic pathways (SSPs) (SSP1, SSP2 and SSP5), for the middle and end of century (2041-2070 and 2071-2100). The results show a reasonable agreement between the modeled and observed MHW property trends, indicating increases in the frequency, duration and intensity of MHWs along the historical period. For the period 1982-2014, both the ∼2 mean observed events per year and the mean intensity of 0.35 °C above the threshold are underestimated by the multi-model ensemble (MME) mean by 21% and 31%, respectively, while the observed duration of ∼12 d are overestimated by 100%. The future MHWs are expected to increase in duration and intensity, where a near permanent MHW occurs with reference to the historical climate conditions, mainly by the end of the 21st century. The future MHWs intensity, projected by the MME mean, increases in the range of 0.2 °C to 1.5 °C, from the least to the most severe pathways. The GCMs biases obtained with CMIP6 revealed to be in line with the CMIP5 biases, reinforcing the need to use high spatial resolution models to characterize MHW.
The incorporation of nanomaterials (NMs), including metal(loid) oxide (MOx) nanoparticles (NPs), in the most diversified consumer products, has grown enormously in recent decades. Consequently, the ...contact between humans and these materials increased, as well as their presence in the environment. This fact has raised concerns and uncertainties about the possible risks of NMs to human health and the adverse effects on the environment. These concerns underline the need and importance of assessing its nanosecurity. The present review focuses on the main mechanisms underlying the MOx NPs toxicity, illustrated with different biological models: release of toxic ions, cellular uptake of NPs, oxidative stress, shading effect on photosynthetic microorganisms, physical restrain and damage of cell wall. Additionally, the biological models used to evaluate the potential hazardous of nanomaterials are briefly presented, with particular emphasis on the yeast
Saccharomyces cerevisiae,
as an alternative model in nanotoxicology. An overview containing recent scientific advances on cellular responses (toxic symptoms exhibited by yeasts) resulting from the interaction with MOx NPs (inhibition of cell proliferation, cell wall damage, alteration of function and morphology of organelles, presence of oxidative stress bio-indicators, gene expression changes, genotoxicity and cell dead) is critically presented. The elucidation of the toxic modes of action of MOx NPs in yeast cells can be very useful in providing additional clues about the impact of NPs on the physiology and metabolism of the eukaryotic cell. Current and future trends of MOx NPs toxicity, regarding their possible impacts on the environment and human health, are discussed.
Key points
•
The potential hazardous effects of MOx NPs are critically reviewed
.
•
An overview of the main mechanisms associated with MOx NPs toxicity is presented
.
•
Scientific advances about yeast cell responses to MOx NPs are updated and discussed
.
This study proposes a dynamically downscaled climatology of Portugal, produced by a high resolution (9 km) WRF simulation, forced by 20 years of ERA-Interim reanalysis (1989–2008), nested in an ...intermediate domain with 27 km of resolution. The Portuguese mainland is characterized by large precipitation gradients, with observed mean annual precipitation ranging from about 400 to over 2,200 mm, with a very wet northwest and rather dry southeast, largely explained by orographic processes. Model results are compared with all available stations with continuous records, comprising daily information in 32 stations for temperature and 308 for precipitation, through the computation of mean climatologies, standard statistical errors on daily to seasonally timescales, and distributions of extreme events. Results show that WRF at 9 km outperforms ERA-Interim in all analyzed variables, with good results in the representation of the annual cycles in each region. The biases of minimum and maximum temperature are reduced, with improvement of the description of temperature variability at the extreme range of its distribution. The largest gain of the high resolution simulations is visible in the rainiest regions of Portugal, where orographic enhancement is crucial. These improvements are striking in the high ranking percentiles in all seasons, describing extreme precipitation events. WRF results at 9 km compare favorably with published results supporting its use as a high-resolution regional climate model. This higher resolution allows a better representation of extreme events that are of major importance to develop mitigation/adaptation strategies by policy makers and downstream users of regional climate models in applications such as flash floods or heat waves.
1. Species traits have been frequently used in ecological studies in an attempt to develop a general ecological framework linking biological communities to habitat pressures. The trait approach ...offers a mechanistic alternative to traditional taxonomy-based descriptors. This review focuses on research employing traits as biomonitoring tools for freshwater ecosystems, although the lessons learned have wider application in the assessment of other ecosystem types. 2. We review the support from ecological theory to employ species traits for biomonitoring purposes (e.g. the habitat templet concept, landscape filtering hypothesis), and the subsequent studies that test the hypotheses arising from these theories, and apply this knowledge under real freshwater biomonitoring scenarios. We also include studies that deal with more specific issues such as trait trade-offs and trait syndromes. 3. We highlight the functional trait approach as one of the most promising tools emerging for biomonitoring freshwater ecosystems. Several technical issues are addressed and solutions are proposed. We discuss the need for: a broader unified trait biomonitoring tool; a more accurate understanding of the natural variation of community patterns of trait expression; approaches to diminish the effects of trait trade-offs and trait syndromes; additional life history and ecological requirement studies; and the detection of specific impacts under multiple stressor scenarios. 4. Synthesis and applications. This review provides biologists with the conceptual underpinning for the use of species traits as community descriptors and for freshwater biomonitoring and management. We expect that the functional trait approach will ultimately improve communication to managers and legislators of the importance of protecting freshwater ecosystem functions.
Stars and planets both form by accreting material from a surrounding disk. Because they grow from the same material, theory predicts that there should be a relationship between their compositions. In ...this study, we search for a compositional link between rocky exoplanets and their host stars. We estimate the iron-mass fraction of rocky exoplanets from their masses and radii and compare it with the compositions of their host stars, which we assume reflect the compositions of the protoplanetary disks. We find a correlation (but not a 1:1 relationship) between these two quantities, with a slope of >4, which we interpret as being attributable to planet formation processes. Super-Earths and super-Mercuries appear to be distinct populations with differing compositions, implying differences in their formation processes.
Recommendations
To identify a person with diabetes at risk for foot ulceration, examine the feet annually to seek evidence for signs or symptoms of peripheral neuropathy and peripheral artery ...disease. (GRADE strength of recommendation: strong; Quality of evidence: low)
In a person with diabetes who has peripheral neuropathy, screen for a history of foot ulceration or lower‐extremity amputation, peripheral artery disease, foot deformity, pre‐ulcerative signs on the foot, poor foot hygiene and ill‐fitting or inadequate footwear. (Strong; Low)
Treat any pre‐ulcerative sign on the foot of a patient with diabetes. This includes removing callus, protecting blisters and draining when necessary, treating ingrown or thickened toe nails, treating haemorrhage when necessary and prescribing antifungal treatment for fungal infections. (Strong; Low)
To protect their feet, instruct an at‐risk patient with diabetes not to walk barefoot, in socks only, or in thin‐soled standard slippers, whether at home or when outside. (Strong; Low)
Instruct an at‐risk patient with diabetes to daily inspect their feet and the inside of their shoes, daily wash their feet (with careful drying particularly between the toes), avoid using chemical agents or plasters to remove callus or corns, use emollients to lubricate dry skin and cut toe nails straight across. (Weak; Low)
Instruct an at‐risk patient with diabetes to wear properly fitting footwear to prevent a first foot ulcer, either plantar or non‐plantar, or a recurrent non‐plantar foot ulcer. When a foot deformity or a pre‐ulcerative sign is present, consider prescribing therapeutic shoes, custom‐made insoles or toe orthosis. (Strong; Low)
To prevent a recurrent plantar foot ulcer in an at‐risk patient with diabetes, prescribe therapeutic footwear that has a demonstrated plantar pressure‐relieving effect during walking (i.e. 30% relief compared with plantar pressure in standard of care therapeutic footwear) and encourage the patient to wear this footwear. (Strong; Moderate)
To prevent a first foot ulcer in an at‐risk patient with diabetes, provide education aimed at improving foot care knowledge and behaviour, as well as encouraging the patient to adhere to this foot care advice. (Weak; Low)
To prevent a recurrent foot ulcer in an at‐risk patient with diabetes, provide integrated foot care, which includes professional foot treatment, adequate footwear and education. This should be repeated or re‐evaluated once every 1 to 3 months as necessary. (Strong; Low)
Instruct a high‐risk patient with diabetes to monitor foot skin temperature at home to prevent a first or recurrent plantar foot ulcer. This aims at identifying the early signs of inflammation, followed by action taken by the patient and care provider to resolve the cause of inflammation. (Weak; Moderate)
Consider digital flexor tenotomy to prevent a toe ulcer when conservative treatment fails in a high‐risk patient with diabetes, hammertoes and either a pre‐ulcerative sign or an ulcer on the distal toe. (Weak; Low)
Consider Achilles tendon lengthening, joint arthroplasty, single or pan metatarsal head resection, or osteotomy to prevent a recurrent foot ulcer when conservative treatment fails in a high‐risk patient with diabetes and a plantar forefoot ulcer. (Weak; Low)
Do not use a nerve decompression procedure in an effort to prevent a foot ulcer in an at‐risk patient with diabetes, in preference to accepted standards of good quality care. (Weak; Low)
•Fish exposed to Au-NP had gold in their body and a decreased predatory performance.•Thus, exposure to Au-NP may negatively affect the health and fitness of P. microps.•Temperature rise increased ...gold body burden and interacted with chemicals’ effects.•The presence of MP did not change the toxic effects of Au-NP to P. microps.
Knowledge on multi-stressors effects required for environmental and human risk assessments is still limited. This study investigated the combined effects of gold nanoparticles (Au-NP), microplastics (MP) and temperature increase on Pomatoschistus microps, an important prey for several higher level predators, including some species edible to humans. Four null hypotheses were tested: H01: P. microps juveniles do not take up Au-NP through the water; H02: Au-NP (ppb range) are not toxic to juveniles; H03: the presence of MP do not influence the effects of Au-NP on juveniles; H04: temperature increase (20–25°C) does not change the effects of the tested chemicals on juveniles. Wild juveniles were acclimated to laboratory conditions. Then, they were exposed to Au-NP (≈5nm diameter) and MP (polyethylene spheres, 1–5μm diameter), alone and in mixture, at 20°C and 25°C, in semi-static conditions. After 96h of exposure to Au-NP, fish had gold in their body (0.129–0.546μg/g w.w.) leading to H01 refusal. Exposure to Au-NP alone caused a predatory performance decrease (≈−39%, p<0.05) leading to H02 refusal. MP did not change the Au-NP toxicity leading to H03 acceptance. Temperature rise significantly increased the concentration of gold in fish exposed to Au-NP (≈2.3 fold), and interacted with chemical effects (e.g. glutathione S-transferases activity) leading to H04 refusal. Thus, the results of this study highlight the importance of further investigating the effects of multi-stressors on marine fish, particularly the effects of temperature on the uptake, biotransformation, elimination and effects of nanoparticles and microplastics, either alone or in mixture. This knowledge is most important to improve the basis for environmental and human risk assessments of these environmental contaminants of high concern.
Mammalian SWI/SNF chromatin remodelling complexes exist in three distinct, final-form assemblies: canonical BAF (cBAF), PBAF and a newly characterized non-canonical complex (ncBAF). However, their ...complex-specific targeting on chromatin, functions and roles in disease remain largely undefined. Here, we comprehensively mapped complex assemblies on chromatin and found that ncBAF complexes uniquely localize to CTCF sites and promoters. We identified ncBAF subunits as synthetic lethal targets specific to synovial sarcoma and malignant rhabdoid tumours, which both exhibit cBAF complex (SMARCB1 subunit) perturbation. Chemical and biological depletion of the ncBAF subunit, BRD9, rapidly attenuates synovial sarcoma and malignant rhabdoid tumour cell proliferation. Importantly, in cBAF-perturbed cancers, ncBAF complexes maintain gene expression at retained CTCF-promoter sites and function in a manner distinct from fusion oncoprotein-bound complexes. Together, these findings unmask the unique targeting and functional roles of ncBAF complexes and present new cancer-specific therapeutic targets.
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