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This international scale study measured the prevalence of indoor microplastics (MPs) in deposited dust in 108 homes from 29 countries over a 1-month period. Dust borne MPs shape, colour, and length were determined using microscopy and the composition measured using µFTIR. Human health exposure and risk was assessed along with residential factors associated with MPs via a participant questionnaire. Samples were categorised according to each country's gross national income (GNI). Synthetic polymers dominated in low income (LI) (39%) and high income (HI) (46%) while natural fibres were the most prevalent in medium income (MI) (43%) countries. Composition and statistical analysis showed that the main sources of MPs and dust were predominantly from indoor sources. Across all GNI countries, greater vacuuming frequency was associated with lower MPs loading. High income country samples returned higher proportions of polyamides and polyester fibres, whereas in LI countries polyurethane was the most prominent MPs fibre. Exposure modelling showed infants (0-2 years) were exposed to the highest MPs dose through inhalation (4.5 × 10-5 ± 3 × 10-5) and ingestion (3.24 × 10-2 ± 3.14 × 10-2) mg/kg-Bw/day. Health risk analysis of constituent monomers of polymers indicates cancer incidence was estimated at 4.1-8.7 per million persons across age groups. This study's analysis showed socio-economic factors and age were dominant variables in determining dose and associated health outcomes of MPs in household dust.
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Poluição do Ar em Ambientes Fechados , Poeira , Poluição do Ar em Ambientes Fechados/análise , Poeira/análise , Monitoramento Ambiental , Humanos , Lactente , Microplásticos , Nylons , Plásticos/análise , Poliésteres , Poliuretanos/análise , Prevalência , Medição de RiscoRESUMO
INTRODUCTION: Respiratory distress is one of the life-threatening conditions in preterm infants. Sensory deprivation in preterm infants hospitalized in the intensive care units affects their physiological and psychological development. Therefore, this study is an attempt to compare the effects of foot and palm reflexology on respiratory distress in infants subjected to noninvasive ventilation. METHODS: In this clinical study, 150 infants hospitalized at Fatemieh Hospital in Hamadan were randomly assigned to 3 groups. In the intervention groups, the reflexology massage to foot and palm was performed for 10 min within 3 days in 6 rounds. In the control group, leg warming was performed. In each group, the personal information checklist, the respiratory distress score, oxygen saturation percentage, and respiratory rate before and after the daily intervention were examined. Data analysis was performed using the standard statistical tests in SPSS. RESULTS: The results mirrored the statistically significant difference between the intervention and control groups 3 days into the intervention with regard to the average oxygen saturation percentage, respiratory rate, and the respiratory distress score (p < 0.05). When eliminating the effect of confounding variables, therapeutic intervention applied to palm compared to foot had a greater effect on reducing respiratory distress score in the studied infants. CONCLUSION: The reflexology massage method, especially palm reflexology massage, contributes to the mitigation of respiratory distress in preterm infants subjected to noninvasive ventilation. Hence, this low-cost and efficient intervention program can be recommended as a complementary method for preterm infants with respiratory distress.
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Manipulações Musculoesqueléticas , Ventilação não Invasiva , Síndrome do Desconforto Respiratório do Recém-Nascido , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Massagem/métodos , Síndrome do Desconforto Respiratório do Recém-Nascido/terapiaRESUMO
People spend increasing amounts of time at home, yet the indoor home environment remains understudied in terms of potential exposure to toxic trace metals. We evaluated trace metal (and metalloid) concentrations (As, Cu, Cr, Mn, Ni, Pb, and Zn) and health risks in indoor dust from homes from 35 countries, along with a suite of potentially contributory residential characteristics. The objective was to determine trace metal source inputs and home environment conditions associated with increasing exposure risk across a range of international communities. For all countries, enrichments compared to global crustal values were Zn > Pb > Cu > As > Cr > Ni; with the greatest health risk from Cr, followed by As > Pb > Mn > Cu > Ni > Zn. Three main indoor dust sources were identified, with a Pb-Zn-As factor related to legacy Pb sources, a Zn-Cu factor reflecting building materials, and a Mn factor indicative of natural soil sources. Increasing home age was associated with greater Pb and As concentrations (5.0 and 0.48 mg/kg per year of home age, respectively), as were peeling paint and garden access. Therefore, these factors form important considerations for the development of evidence-based management strategies to reduce potential risks posed by indoor house dust. Recent findings indicate neurocognitive effects from low concentrations of metal exposures; hence, an understanding of the home exposome is vital.
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Metaloides , Metais Pesados , Oligoelementos , China , Poeira/análise , Monitoramento Ambiental , Humanos , Metaloides/análise , Medição de Risco , Oligoelementos/análiseRESUMO
Today, the use of nutrients derived from natural bioactive compounds application in the food, pharmaceutical, and cosmetic industries is on the increase. This paper aimed to evaluate the amino acids profile (essential and non-essential) and pigments composition (chlorophyll a, carotenoids, and phycocyanin) of Arthrospira platensis (a blue-green microalga) cultivation in a flat-plate photobioreactor under various types of light-emitting diodes (red: 620-680 nm, white: 380-780 nm, yellow: 570-600nm, blue: 445-480 nm). The maximum biomass concentration (604.96 mg L-1) occurred when the red LED was applied for cultivation, and the minimum biomass concentration (279.39 mg L-1) was obtained under blue LED. The sequence of pigments and amino acids concentrations (mg L-1culture volume) was approximately in accordance with the biomass productivity. It means the red light produces the maximum concentration of pigments (chlorophyll a: 5.42, carotenoids: 2.92, phycocyanin: 67.54 mg L-1) and amino acids (essential amino acids: 110.47, nonessential amino acids: 179.10 mg L-1). Nevertheless, when these values were measured in mg per g of dry weight, the utmost contents were observed in microalgal products cultivated under blue LED. These consequences are due to the highest cell productivity and the most extended length of cells that occurred under red and blue LEDs, respectively.
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We launched the VegeSafe program in 2013 to assist Australians concerned about exposure to contaminants in their soils and gardens. VegeSafe analyses garden soils provided by citizens for trace metals at our laboratory at little to no cost, with easy-to-follow guidance on any intervention required. The response was overwhelming-Australians submitted 17,256 soils from 3,609 homes, and in turn VegeSafe researchers now have unparalleled household-scale data, providing new insights into urban trace metal contamination. The results are sobering, with 35% of homes, particularly those that are older, painted and located in inner cities having soils above the Australian residential guideline (300 mg/kg) for the neurotoxic trace metal lead (Pb). Exposure pathway, blood Pb concentration and vegetable uptake modelling showed the communities in these locations were most at risk. VegeSafe is transformative: 94% of participants better understood contaminants, 83% felt safer in their home environment and 40% undertook remedial action based on their results. The two-way nature of this program enables education of citizens about environmental contaminants, advances public health, and delivers impactful science.
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Ciência do Cidadão , Metais Pesados , Poluentes do Solo , Austrália , Cidades , Monitoramento Ambiental , Jardins , Humanos , Metais Pesados/análise , Solo , Poluentes do Solo/análiseRESUMO
Limited attention has been given to the presence of MPs in the atmospheric environment, particularly in indoor environments where people spend about 90% of their time. This study quantitatively assesses the prevalence, source and type of MPs in Australian homes with the goal of evaluating human health exposure potential. Thirty-two airborne indoor deposited dust samples were collected in glass Petri dishes from Sydney (Australia) homes, over a one-month period in 2019. Participants completed a questionnaire on their household characteristics. Samples were analysed using a stereomicroscope, a fluorescent microscope and micro-Fourier transform infrared (FTIR) spectroscopy for their colour, size, shape and composition. Inhalation and ingestion rates were modelled using US EPA exposure factors. Microplastic fibre deposition rates ranged from 22 to 6169 fibres/m2/day. Deposited dust comprised 99% fibres. The highest proportion of fibres (19%) were 200-400 µm in length. The majority were natural (42%); 18% were transformed natural-based fibres; and 39% were petrochemical based. A significant difference was observed between the deposition rate and the main floor covering (p-value <0.05). Polyethylene, polyester, polyamide, polyacrylic, and polystyrene fibres were found in higher abundance in homes with carpet as the main floor covering. Where carpet was absent, polyvinyl fibres were the most dominant petrochemical fibre type, indicating the role of flooring materials (e.g. wood varnishes) in determining MP composition. Vacuum cleaner use was significantly related to MP deposition rates (p-value <0.05). MP ingestion rates peaked at 6.1 mg/kg-Bw/year for ages 1-6, falling to a minimum of 0.5 mg/kg-Bw/year in >20 years age group. Mean inhaled MP weight and count was determined to be 0.2±0.07 mg/kg-Bw/year and 12891±4472 fibres/year. Greatest inhalation intake rates were for the <0.5-yr age group, at 0.31 mg/kg-Bw/year. The study data reveal that MPs are prevalent in Australian homes and that the greatest risk of exposure resides with young children. Notwithstanding the limited number of global studies and the different methods used to measure MPs, this study indicates Australian deposition and inhalation rates are at the lower end of the exposure spectrum.
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Poluição do Ar em Ambientes Fechados , Microplásticos , Poluição do Ar em Ambientes Fechados/análise , Austrália , Criança , Pré-Escolar , Poeira/análise , Exposição Ambiental/análise , Monitoramento Ambiental , Humanos , Lactente , PlásticosRESUMO
The main purpose of present study was to investigate the effects of elastic band resistance training (EBRT) on muscle quality (MQ), serum osteosarcopenic obesity (OSO) biomarkers, bone density and functional profile in women living with OSO syndrome. The eligible participants, aged 65 to 80 years, were selected by a physician. Accordingly, a total number of 63 women with OSO syndrome were recruited and assessed using a dual energy X-ray absorptiometry (DXA) instrument, body mass index (BMI) > 30 kg/m2, -2.5 ≤ T-score ≤ -1.0 of L1-L4, and/or total femur or femoral neck, and gait speed (10-meter walk test (10MWT)) ≤ 1 (m/s2). The 12-week supervised EBRT was designed to train all major muscle groups for 3 times per week. In the first two sessions, the participants became familiar with targeted number of repetitions (TNRs) and OMNI-resistance exercise scale (OMNI-RES) to control exercise intensity. Following an adaptation phase of 4 weeks (1 set of 12 rep) using low resistance (yellow Thera-Band), exercise intensity progressively increased by adapting the resistance of the elastic band (based on the Thera-Band® force-elongation table) from yellow to red and further to black. The participants in the control group also received telephone contacts or face-to-face interviews on a weekly basis to maintain their typical diet and activity habits. A two-way repeated measures ANOVA was employed to determine the main changes (2 times×2 groups) after 12 weeks of training. Partial eta-squared (ηp2) was additionally used to determine ES in ANOVA tests. At all the stages of data analysis in this RCT, intention-to-treat (ITT) analysis was performed. The results of two-way ANOVA showed significant elevations in E2 (F = 7.881, p = 0.006, ES = 0.079), MQ (F = 4.225, p = 0.043, ES = 0.044), OSO Z-score (F = 7.091, p = 0.030, ES = 0.069), 30-s chair stand test (F = 4.599, p = 0.036, ES = 0.063) and hand grip strength (F = 6.411, p = 0.013, ES = 0.065) in the experimental group compared with those in the controls. Besides, there were no significant differences in CAF (F = 0.456, p = 0.501, ES = 0.005), CTX-I (F = 3.427, p = 0.067, ES = 0.036), adiponectin (F = 2.733, p = 0.102, ES = 0.029), sTnT (F = 3.245, p = 0.075, ES = 0.034), sclerostin (F = 2.927, p = 0.091, ES = 0.034), gait speed (10MWT) (F = 1.524, p = 0.220, ES = 0.016), 6MWT (F = 1.169, p = 0.284, ES = 0.017) and TUG (F = 1.502, p = 0.225, ES = 0.022), BMI (F = 0.354, p = 0.553, ES = 0.004), BFP (F = 2.888, p = 0.093, ES = 0.030), body mass content (BMC) (F = 0.030, p = 0.862, ES = 0.001) and BMD (F = 0.335, p = 0.564, ES = 0.004) between study groups. Taken together, the results of this study illustrated significant differences only in some OSO markers between groups after 48 h of chronic EBRT in women affected with OSO syndrome. Further research is thus recommended to design machine-based and elastic band-based training regimes at different intensities and volumes.
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Treinamento Resistido , Absorciometria de Fóton , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Feminino , Força da Mão , Humanos , Obesidade/terapiaRESUMO
Aluminium (Al) water pollution is an increasing environmental problem and comprehensive analysis of toxic responses of aquatic primary producer organisms is imperative. We characterized the antioxidant response of Scenedesmus sp. microalga to Al-induced oxidative stress. After 72 h of exposure to Al (0, 10, and 100 µM) in a modified Bold Basal Medium (pH 5.0), we observed cell aggregation and alterations in the subcellular structure, strong lipid peroxidation and oxidative stress induction (detected with the fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate) in parallel with Al accumulation in cells. At the same time, Al toxicity caused depletion of important macronutrients like Ca, which is important for cell-wall structure. Analysis of antioxidant enzymatic activities in Al-treated Scenedesmus cells revealed that catalase, ascorbate peroxidase, as well as different isoforms of superoxide dismutase were inhibited especially at the highest Al dose (100 µM), cells that accumulated the highest concentration of Al. On the other hand, glutathione reductase activity increased at that Al concentration. Immunodetection after Western-blotting confirmed that only ascorbate peroxidase inhibition was apparently due to a decrease in enzyme levels. However, the inhibition of catalase and activation of glutathione reductase activities seemed related with post-translational modifications in protein function as protein expression decreased or increased, respectively under Al stress. Our results may help to understand toxic mechanisms triggered by Al in freshwater microalgae, which in turn could aid to select suitable biomarkers of Al contamination in aquatic ecosystems.
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Alumínio/efeitos adversos , Antioxidantes/metabolismo , Estresse Oxidativo , Scenedesmus/efeitos dos fármacos , Poluentes Químicos da Água/efeitos adversos , Microalgas/efeitos dos fármacos , Microalgas/metabolismo , Scenedesmus/metabolismoRESUMO
This study examines residential indoor dust from 224 homes in Sydney, Australia for trace element concentrations measured using portable X-ray Fluorescence (pXRF) and their potential risk of harm. Samples were collected as part of a citizen science program involving public participation via collection and submission of vacuum dust samples for analysis of their As, Cr, Cu, Mn, Ni, Pb and Zn concentrations. The upper 95% confidence level of the mean values for 224 samples (sieved to <250⯵m) were 20.2â¯mg/kg As, 99.8â¯mg/kg Cr, 298â¯mg/kg Cu, 247â¯mg/kg Mn, 56.7â¯mg/kg Ni, 364â¯mg/kg Pb and 2437â¯mg/kg Zn. The spatial patterns and variations of the metals indicate high homogeneity across Sydney, but with noticeably higher Pb values in the older areas of the city. Potential hazard levels were assessed using United States Environmental Protection Agency's (US EPA) carcinogenic, non-carcinogenic and Integrated Exposure Uptake Biokinetic (IEUBK) model human health risk assessment tools for children and adults. US EPA hazard indexes (HI) for Cr and Pb were higher than the safe level of 1.0 for children. HIâ¯>â¯1 suggests potential non-carcinogenic health effects. Carcinogenic risks were estimated for As, Cr and Pb whose carcinogenic slope factors (CSF) were available. Only the risk factor for Cr exceeded the US EPA's carcinogenic threshold (1â¯×â¯10-4) for children. Children aged 1-2â¯years had the highest predicted mean child blood lead (PbB) of 4.6⯵g/dL, with 19.2% potentially having PbB exceeding 5⯵g/dL and 5.80% exceeding 10⯵g/dL. The Cr and Pb levels measured in indoor dust therefore pose potentially significant adverse health risks to children.
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Poluição do Ar em Ambientes Fechados/efeitos adversos , Poeira , Oligoelementos/efeitos adversos , Adulto , Austrália , Carcinógenos/análise , Criança , Pré-Escolar , Poeira/análise , Exposição Ambiental/análise , Monitoramento Ambiental , Humanos , Lactente , Medição de Risco , Oligoelementos/análiseRESUMO
One of the major environmental problems nowadays is petroleum hydrocarbons contamination. Bioremediation is widely used for cleaning ecosystems contaminated with petroleum hydrocarbons. This study was carried out to investigate the response of five microalgae strains isolated from different regions in Iran for 1% n-dodecane (DOD) degradation. The results revealed that Leptolyngbya fragilis ISC 108 is the most effective strain to utilize n-DOD as growth substrate under a mixotrophic condition. Currently, there is little information about mechanisms involved in microalgae response against DOD. The activity of antioxidant enzymes and total lipid and carbohydrate contents were observed to be greater in DOD-treated L. fragilis ISC 108. Lower values of lipid peroxidation and H2O2 along with an increase of dry weight and specific growth rate in L. fragilis ISC 108 under DOD treatment shows that at the cellular level this strain is better equipped with an efficient oxygen radical scavenging system. In conclusion, this study proposes that L. fragilis ISC 108 can be considered an ideal candidate for use in bioremediation of DOD contaminated sites.
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Petróleo , Poluentes do Solo , Alcanos , Biodegradação Ambiental , Ecossistema , Hidrocarbonetos , Peróxido de Hidrogênio , Irã (Geográfico) , Solo/química , Microbiologia do SoloRESUMO
The present study is pursuing our previous research, focused on some aspects of Nostoc entophytum ISC32 cell response to the stress caused by exposure to cadmium at the cellular and molecular levels. Variations in the antioxidant system (catalase and ascorbate peroxidase activity) of N. entophytum ISC32 exposed to varying concentrations of Cd (2, and 5â¯mg/L) resulted in a significant increase in the activity of both catalase and peroxidase. Activity of these enzymes was, however, not significantly changed in the presence of Cd concentrations of 10 and 20â¯mg/L. Levels of lipid peroxidation, as measured by malondialdehyde (MDA) assay, were observed in response to exposure to Cd (20â¯mg/L). There was, however, a sharp drop in both antioxidant and lipid peroxidation activities of Cd treated cells after 5 days exposure, likely in consequence of cellular damage. The content of chlorophyll a and phycobiliproteins of living cells were altered under Cd-induced conditions. TEM images of cyanobacterial cells treated with Cd showed cell surface alteration and modification along with altered cellular microcompartments. Cyanobacterial cells treated with Cd at concentrations below the minimum inhibitory concentration (MIC) remained with no apparent structural changes. However, at a higher concentration of Cd (30â¯mg/L), a clear detachment effect was observed between the mucilage external layer and cell membrane which may be attributed to cell plasmolysis due to toxic effects of Cd. Subsequently, the thickness of the ring-shaped mucilage external layer increased likely as a result of the cell defense mechanisms against toxic concentrations of Cd. Characterization of cells treated with Cd (30 and 150â¯mg/L) by scanning electron microscopy (SEM) indicated cell shrinkage with varying degrees of distortion and surface wrinkling. Energy-dispersive X-ray spectrometry (EDS) analysis suggested that Cd was not present as nanoparticles within the cell, but in the form of salt or other molecular structures. The up-regulation of chaperons was confirmed for GroEL and HtpG using real-time PCR and northern blot analyses. Interestingly, the expression of GroEL was markedly increased at lower Cd concentration (5â¯mg/L). However, the ISC32 strain accrued higher levels of HtpG transcript in response to an elevated concentration of Cd (15â¯mg/L). This pattern seems to be related to the fast and early induction of GroEL, which may be necessary for induction of other factors and heat shock proteins such as HtpG in Cd-treated Nostoc cells. The result of this study paves the way for a more detailed exploration of Cd effects on the defense mechanisms of cyanobacteria. Our research also shed some light on how cyanobacterial cells have evolved to respond to the heavy metal toxicity at the cellular, molecular and ultrastructural levels.
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Proteínas de Bactérias/metabolismo , Cádmio/toxicidade , Chaperonina 60/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Nostoc/efeitos dos fármacos , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila A/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Nostoc/enzimologia , Nostoc/metabolismo , Nostoc/ultraestrutura , Oxirredução , Estresse Oxidativo , Peroxidase/metabolismo , Peroxidases/metabolismo , Ficobiliproteínas/metabolismo , Superóxido Dismutase/metabolismoRESUMO
Soils play a vital role in the quality of the urban environment and the health of its residents. City soils and street dusts accumulate various contaminants and particularly potentially toxic elements (PTEs) from a variety of human activities. This study investigates the current condition of elemental concentration in the urban soils of Hamedan, the largest and the fastest-growing city in western Iran. Thirty-four composite soil samples were collected from 0 to 10 cm topsoil of various land uses in Hamedan city and were analyzed for total concentration of 63 elements by ICP-MS. The possible sources of elemental loadings were verified using multivariate statistical methods (principal component analysis and cluster analysis) and geochemical indices. The spatial variability of the main PTEs was mapped using geographic information system (GIS) technique. The results revealed a concentration for As, Co, Cr, Mn, Mo, Ni, and V in the soil samples comparable to the background values as well as a range of associations among these elements in a single component suggesting geogenic sources related to geological and pedogenic processes, while the soils mostly presented a moderate to considerable enrichment/contamination of Cd, Zn, Pb, and Sb and moderate enrichment/contamination of Cu, Zn, and Mo. It was found that anthropogenic factors, vehicular traffic in particular, control the concentration of a spectrum of elements that are typical of human activities, i.e., Cd, Cu, Hg, Pb, Sb, and Zn. Lead and Sb were both the most enriched elements in soils with no correlation with land use highlighting general urban emissions over time and the impact of transport networks directly on soil quality. The highest concentrations of As were recorded in the southern part of the city reflecting the influence of metamorphic rocks. The effect of the geological substrate on the Co and Ni contents was confirmed by their maximum concentrations in the city's marginal areas. However, high spatial variability of urban elements' contents displayed the contribution of various human activities. In particular, the increased concentration of Cd, Sb, and Pb was found to be consistent with the areas where vehicular traffic is heaviest.
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Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Cidades , Poeira/análise , Monitoramento Ambiental/métodos , Sistemas de Informação Geográfica , Geologia , Humanos , Irã (Geográfico)RESUMO
The vegetative growth of Haematococcus pluvialis TMU1 was studied under batchwise cultivation in three common media, namely BBM, BG11, and 3NBBM. The BBM provided the best condition for the algal growth. It was further studied at different levels of nitrate and phosphate as macronutrients as well as iron and boron as trace elements. The dose-response of the algal growth to these macro/micronutrients was modeled with Monod/hormetic-type kinetics. Applying the modified BBM with 3-fold higher phosphate led to the highest cell density and up to 86% increase in the growth rate. At an inoculum size of 2â¯×â¯105 cells mL-1, the algal growth rate in BBM containing either 0.185â¯mM boron or 0.046â¯mM iron was higher than the medium containing half or twice ion levels. These optimal concentrations depend on inoculum size, so that changes from the optima increased the level of peroxide signaling molecules and induced defense pathways.
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Clorófitas , Nitratos , Reatores Biológicos , Clorófitas/crescimento & desenvolvimento , Transdução de SinaisRESUMO
Among nine cyanobacterial strains isolated from oil-contaminated regions in southern Iran, an isolate with maximum cadmium uptake capacity was selected and identified on the basis of analysis of morphological criteria and 16S rRNA gene sequence similarity as Nostoc entophytum (with 99% similarity). The isolate was tentatively designated N. entophytum ISC32. The phylogenetic affiliation of the isolates was determined on the basis of their 16S rRNA gene sequence. The maximum amount of Cd(II) adsorbed by strain ISC32 was 302.91 mg g(-1) from an initial exposure to a solution with a Cd(II) concentration of 150 mg l(-1). The cadmium uptake by metabolically active cells of cyanobacterial strain N. entophytum ISC32, retained in a clinostat for 6 days to simulate microgravity conditions, was examined and compared with that of ground control samples. N. entophytum ISC32 under the influence of microgravity was able to take up cadmium at amounts up to 29% higher than those of controls. The activity of antioxidant enzymes including catalase and peroxidase was increased in strain ISC32 exposed to microgravity conditions in a clinostat for 6 days, as catalase activity of the cells was more than three times higher than that of controls. The activity of the peroxidase enzyme increased by 36% compared with that of the controls. Membrane lipid peroxidation was also increased in the cells retained under microgravity conditions, up to 2.89-fold higher than in non-treated cells. Images obtained using scanning electron microscopy showed that cyanobacterial cells form continuous filaments which are drawn at certain levels, while the cells placed in a clinostat appeared as round-shaped, accumulated together and distorted to some extent.
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Antioxidantes/metabolismo , Transporte Biológico/fisiologia , Cádmio/metabolismo , Poluentes Ambientais/metabolismo , Nostoc/metabolismo , Biodegradação Ambiental , Biomassa , Catalase/metabolismo , Citoesqueleto/metabolismo , Peroxidação de Lipídeos/fisiologia , Lipídeos de Membrana/metabolismo , Microscopia Eletrônica de Varredura , Nostoc/genética , Peroxidase/metabolismo , RNA Ribossômico 16S/genética , Ausência de PesoRESUMO
Substantial reductions in yield caused by drought stress can occur when parts of the root system experience water deficit even though other parts have sufficient access to soil water. To identify proteins associated to drought signaling, rice (Oryza sativa L. cv. IR64.) plants were transplanted into plastic pots with an internal wall dividing each pot into two equal compartments, allowing for equal distribution of soil and the root system between these compartments. The following treatments were applied: either both compartments were watered daily ("wet" roots), or water was withheld from both compartments ("dry" roots), or water was withheld from only one of the two compartments in each pot ("wet" and "dry" roots). The substantial differences in physiological parameters of different growth conditions were accompanied by differential changes in protein abundances. Label-free quantitative shotgun proteomics have resulted in identification of 1383 reproducible proteins across all three conditions. Differentially expressed proteins were categorized within 17 functional groups. The patterns observed were interesting in that in some categories such as protein metabolism and oxidation-reduction, substantial numbers of proteins were most abundant when leaves were receiving signals from "wet" and "dry" roots. In yet other categories such as transport, several key transporters were surprisingly abundant in leaves supported by partially or completely droughted root systems, especially plasma membrane and vacuolar transporters. Stress-related proteins behaved very consistently by increasing in droughted plants but notably some proteins were most abundant when roots of the same plant were growing in both wet and dry soils. Changes in carbohydrate-processing proteins were consistent with the passive accumulation of soluble sugars in shoots under drought, with hydrolysis of sucrose and starch synthesis both enhanced. These results suggest that drought signals are complex interactions and not simply the additive effect of water supply to the roots.
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Oryza/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Água , Eletroforese em Gel de Poliacrilamida , Proteômica , Espectrometria de Massas em TandemRESUMO
Rice (Oryza sativa L. cv. IR64) was grown in split-root systems to analyze long-distance drought signaling within root systems. This in turn underpins how root systems in heterogeneous soils adapt to drought. The approach was to compare four root tissues: (1) fully watered; (2) fully droughted and split-root systems where (3) one-half was watered and (4) the other half was droughted. This was specifically aimed at identifying how droughted root tissues altered the proteome of adjacent wet roots by hormone signals and how wet roots reciprocally affected dry roots hydraulically. Quantitative label-free shotgun proteomic analysis of four different root tissues resulted in identification of 1487 nonredundant proteins, with nearly 900 proteins present in triplicate in each treatment. Drought caused surprising changes in expression, most notably in partially droughted roots where 38% of proteins were altered in level compared to adjacent watered roots. Specific functional groups changed consistently in drought. Pathogenesis-related proteins were generally up-regulated in response to drought and heat-shock proteins were totally absent in roots of fully watered plants. Proteins involved in transport and oxidation-reduction reactions were also highly dependent upon drought signals, with the former largely absent in roots receiving a drought signal while oxidation-reduction proteins were strongly present during drought. Finally, two functionally contrasting protein families were compared to validate our approach, showing that nine tubulins were strongly reduced in droughted roots while six chitinases were up-regulated, even when the signal arrived remotely from adjacent droughted roots.