Photoprotective mechanisms and higher photorespiration are key points for iron stress tolerance under heatwaves in rice.

Considering the current climate change scenario, the development of heat-tolerant rice cultivars (Oryza sativa L.) is paramount for cultivation in waterlogged systems affected by iron (Fe) excess. The objective of this work was to investigate the physiological basis of tolerance to excess Fe in rice cultivars that would maintain photosynthetic efficiency at higher temperatures. In an experimental approach, two rice cultivars (IRGA424 - tolerant and IRGA417- susceptible to Fe toxicity) were exposed to two concentrations of FeSO4-EDTA, control (0.019 mM) and excess Fe (7 mM) and subsequent exposition to heatwaves at different temperatures (25 °C - control, 35, 40, 45, 50, and 55 °C). The increase in temperatures resulted in a higher Fe concentration in shoots accompanied by a lower Rubisco carboxylation rate in both cultivars, but with lower damage in the tolerant one. Stomatal limitation only occurred as a late response to Fe toxicity, especially in the sensitive cultivar. The activation of photorespiration as electron sink under Fe excess with increasing temperature during heatwaves appear as a major mechanism to alleviate oxidative stress in cultivars tolerant to excess Fe. The tolerance to iron toxicity and heat stress is associated with increased photoprotective mechanisms driving non-photochemical dissipation.

Photochemical attributes determine the responses of plant species from different functional groups of ferruginous outcrops when grown in iron mining substrates.

Environments originating from banded iron formations, such as the canga , are important reference ecosystems for the recovery of degraded areas by mining. The objective of this work was to evaluate if the relationship between morphofunctional and photosynthetic attributes of native canga species from different functional group results in distinct responses when grown in iron mining tailings substrate. The experiment was carried out with species belonging to different functional groups: a widespread semi-deciduous tree-shrub, Myrcia splendens ; an endemic deciduous shrub, Jacaranda caroba ; and a nitrogen-fixing herbaceous species, Periandra mediterranea . The species were grown in two conditions, reference soil and iron ore tailing. Despite belonging to different functional groups when grown in tailings, the morphofunctional attributes presented similar responses between species. M. splendens was the species most affected by the conditions imposed by the iron ore mining tailings, with decreased light-use efficiency and electron transport. P. mediterranea had satisfactory growth and maintenance of photosynthetic attributes. J. caroba growing in the tailings increased the effective quantum yield of PSII. The photochemical and growth assessments were able to better explain the adaptive strategies developed by the species, guaranteeing a greater chance of success during the rehabilitation of mining substrates.

Diffusion-weighted imaging does not seem to be a predictor of consistency in pituitary adenomas.

PURPOSE: To prospectively evaluate the usefulness of T1-weighted imaging (T1WI) and diffusion-weighted imaging (DWI) sequences in predicting the consistency of macroadenomas. In addition, to determine their values ​​as prognostic factors of surgical outcomes. METHODS: Patients with pituitary macroadenoma and surgical indication were included. All patients underwent pre-surgical magnetic resonance imaging (MRI) that included the sequences T1WI before and after contrast administration and DWI with the apparent diffusion coefficient (ADC) map. Post-surgical MRI was performed at least 3 months after surgery. The consistency of the macroadenomas was evaluated at surgery, and they were grouped into soft and intermediate/hard adenomas. Mean ADC values, signal on T1WI and the ratio of tumor ADC values ​​to pons (ADCR) were compared with tumor consistency and grade of surgical resection. RESULTS: A total of 80 patients were included. A softened consistency was found at surgery in 53 patients and hardened in 27 patients. The median ADC in the soft consistency group was 0.532 × 10-3 mm2/sec (0.306 - 1.096 × 10-3 mm2/sec), and in the intermediate/hard consistency group was 0.509 × 10-3 mm2/sec (0.308 - 0.818 × 10-3 mm2/sec). There was no significant difference between the median values ​​of ADC, ADCR and signal on T1W between the soft and hard tumor groups, or between patients with and without tumor residue. CONCLUSION: Our results did not show usefulness of the DWI and T1WI for assessing the consistency of pituitary macroadenomas, nor as a predictor of the degree of surgical resection.

Tensile bond strength of adhesive mortars with hydroxypropyl methyl cellulose and vinyl acetate-ethylene polymers after thermal storage.

The properties of adhesive mortars can change due to heating, compromising the durability of the coating systems. The aim of this article was to evaluate the influence of cement and polymer contents on the tensile bond strength of adhesive mortars after thermal storage. Ceramic tiling system specimens were prepared with seventeen formulations of adhesive mortars. These specimens were stored under dry (reference) at temperature of 23 ± 2 °C and 60 ± 5% of relative humidity and thermal (temperature of 70 ± 2 °C) conditions. The results showed that the cement content was the major factor concerning tensile bond strength. The vinyl acetate-ethylene (VAE) polymer improved the tensile bond strength of mortars under thermal storage. However, the hydroxypropyl methyl cellulose (HPMC) content contributed to the tensile bond strength only when higher cement contents were used. Besides, microstructure analysis showed that ettringite was degraded during thermal storage.

Study of the Efficiency of a Polycation Using the Diafiltration Technique in the Removal of the Antibiotic Oxytetracycline Used in Aquaculture.

The presence of antibiotics in aquatic systems in recent years has become a global environmental and public health concern due to the appearance of strains resistant to these antibiotics. Oxytetracycline (OXT) is a high-impact antibiotic used for both human and veterinary consumption, and it is the second most used antibiotic in aquaculture in Chile. Based on the above, this problem is addressed using a linear polymer whose structure is composed of aromatic rings and quaternary ammonium groups, which will help enhance the removal capacity of this antibiotic. To obtain the polycation, a radical polymerization synthesis was carried out using (4-vinylbenzyl)-trimethylammonium chloride as the monomer. The polycation was characterized via Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The removal studies were conducted under different experimental conditions such as pH levels (3.0, 5.0, 7.0, 8.0, and 11.0), ionic strength (0.0-0.50 mg L-1 of NaCl), polymer dose (0.25-25.5 mg), variation of the antibiotic concentration (1-100 mg L-1), and evaluation of the maximum retention capacity, as well as load and discharge studies. The antibiotic retention removal was higher than 80.0%. The antibiotic removal performance is greatly affected by the effect of pH, ionic strength, molar ratio, and/or OXT concentration, as these parameters directly affect the electrostatic interactions between the polymer and the antibiotics. The diafiltration technique was shown to be highly efficient for the removal of OXT, with maximum removal capacities of 1273, 966, and 778 mg OXT g-1 polycation. In conclusion, it can be said that coupling water-soluble polymers to the diafiltration technique is an excellent low-cost way to address the problem of antibiotics in aquatic systems.

Rescue method for a stranded giant manta ray (Mobula birostris).

An opportunistic rescue of a stranded 6 m giant manta ray off Ilha Comprida, in São Paulo, southeastern Brazil, revealed a new technique for returning large bodied mobulid rays to the water once beached. The technique, adapted from protocols to move stranded cetaceans, was modified to suit the dorso-ventrally compressed shape of mobulid rays and reduce damage to the animal while being pulled back into deeper water. The method and suggestions for its improvement have been described with the intention of assisting in the rescue of other stranded large mobulids.

High Incidence of Respiratory Syncytial Virus in Children with Community-Acquired Pneumonia from a City in the Brazilian Pre-Amazon Region.

INTRODUCTION: Although fewer children have been affected by the severe form of the coronavirus disease 2019 (COVID-19), community-acquired pneumonia (CAP) continues to be the leading global cause of child hospitalizations and deaths. AIM: This study investigated the incidence of respiratory syncytial virus (RSV) as well its subtypes (RSV A and B), adenovirus (ADV), rhinovirus (HRV), metapneumovirus (HMPV), coronavirus (NL63, OC43, 229E and HKU1), parainfluenza virus subtypes (PI1, PI2 and PI3), bocavirus and influenza A and B viruses (FluA and FluB) in children diagnosed with CAP during the COVID-19 pandemic. METHODS: A total of 200 children with clinically confirmed CAP were initially recruited, of whom 107 had negative qPCR results for SARS-CoV-2 and were included in this study. Viral subtypes were identified using a real-time polymerase chain reaction in the nasopharyngeal swab samples. RESULTS: Viruses were identified in 69.2% of the patients. RSV infections were the most frequently identified (65.4%), with type RSV B being the most prevalent (63.5%). In addition, HCoV 229E and HRV were detected in 6.5% and 3.7% of the patients, respectively. RSV type B was associated with severe acute respiratory infection (ARI) and a younger age (less than 24 months). CONCLUSIONS: New strategies for preventing and treating viral respiratory infections, particularly RSV infections, are necessary.

In vitro galactose impairs energy metabolism in the brain of young rats: protective role of antioxidants.

We, herein, investigated the in vitro effects of galactose on the activity of pyruvate kinase, succinate dehydrogenase (SDH), complex II and IV (cytochrome c oxidase) of the respiratory chain and Na+K+-ATPase in the cerebral cortex, cerebellum and hippocampus of 30-day-old rats. We also determined the influence of the antioxidants, trolox, ascorbic acid and glutathione, on the effects elicited by galactose. Galactose was added to the assay at concentrations of 0.1, 3.0, 5.0 and 10.0 mM. Control experiments were performed without galactose. Galactose, at 3.0, 5.0 and 10.0 mM, decreased pyruvate kinase activity in the cerebral cortex and at 10.0 mM in the hippocampus. Galactose, at 10.0 mM, reduced SDH and complex II activities in the cerebellum and hippocampus, and reduced cytochrome c oxidase activity in the hippocampus. Additionally, decreased Na+K+-ATPase activity in the cerebral cortex and hippocampus; conversely, galactose, at 3.0 and 5.0 mM, increased this enzyme's activity in the cerebellum. Data show that galactose disrupts energy metabolism and trolox, ascorbic acid and glutathione addition prevented the majority of alterations in the parameters analyzed, suggesting the use of antioxidants as an adjuvant therapy in Classic galactosemia.

Antimicrobial effect of quercetin against Streptococcus pneumoniae.

Streptococcus pneumoniae is a bacterium that causes serious infections, including pneumonia. The limited range of available vaccines and the rise of antibiotic-resistant bacteria mean that new treatments are needed. This study looked at the potential of quercetin as an antimicrobial agent against S. pneumoniae in both isolation and in biofilms. The researchers used microdilution tests, checkerboard assays, and death curve assays, as well as in silico and in vitro cytotoxicity evaluations. They found that quercetin at a concentration of 125.0 µg/mL had both inhibitory and bactericidal effects against S. pneumoniae, and these effects were increased when quercetin was combined with ampicillin. Quercetin also reduced the growth of pneumococcal biofilms. In addition, quercetin (absence or in combination with ampicillin) reduced the death time of Tenebrio molitor larvae compared to the infection control. The study also demonstrated that quercetin had low toxicity in both in silico and in vivo assays, suggesting that it could be a promising treatment for infections caused by S. pneumoniae.

Severe equinus cavo-varus correction through triplanar tarsectomy and posterior tibial tendon transfer based on 3D-printed biomodel.

Surgery for severe equine cavo-varus is complex and must be individualized. The interindividual phenotypic variability demands a personalized planning of each foot to be operated. The study's primary goal was to evaluate the function and satisfaction of a series of patients with severe equinus cavo-varus deformity who underwent a triplanar tarsectomy and transposition of the posterior tibial tendon in a single stage surgery after a patient specific 3D biomodel planning. A series of 12 feet (5 patients bilaterally) operated with this technique was analyzed. The cohort comprised 2 females (28.5 %) and 5 males (71.4 %). The median follow-up time was 38.5 months (interquartile range: 24.75-48.75). The Foot and Ankle Disability Index pre (median 32.85; interquartile range: 20-46) and postsurgery (median 72; interquartile range: 56-75.5) were collected and statistically significant differences were observed (p < 0.002). Furthermore, the main variable evaluated was obtaining a plantigrade stable foot. This was clinically evaluated and was achieved in all patients except 1 patient who presented a residual equinus of 5º. This study shows that triplanar tarsectomy and posterior tibial tendon transfer in a single surgical procedure after patient-specific 3D biomodel planning allows for improved function in patients with severe equinus cavus varus foot deformity.

Benefits of Tranexamic Acid in Total Knee Arthroplasty: A Classification and Regression Tree Analysis in Function of Instrumentation, BMI, and Gender.

Tranexamic acid (TXA) is an antifibrinolytic drug that reduces blood loss in patients that undergo Total knee arthroplasty (TKA). Few studies compare its effect on conventional instrumentation (CI) versus patient-specific instrumentation (PSI). The main objective of this study was to understand analytically how TXA usage in both instrumentations influenced blood loss in TKA differently and see if the differences seen could be explained by the patient's body mass index (BMI) and gender. This nonrandomized retrospective study sample consisted of 688 TKA procedures performed on patients who had symptomatic arthrosis resistant to conservative treatment. Descriptive analysis was used to evaluate blood loss using hemoglobin (Hb) mean values and mean variation (%). The Classification and Regression Tree (CRT) method was applied to understand how the independent variables affected the dependent variable. Comparing patients submitted to the same instrumentation, where some received TXA and others did not, patients that received TXA had lower blood loss. Comparing patients who underwent TKA with different instrumentations and without the use of TXA, it was found that patients who underwent TKA with PSI had lower blood loss than those who underwent TKA with CI. However, when these same instruments were compared again, but associated with the use of TXA, the opposite was true with patients undergoing TKA with PSI showing greater blood loss than patients undergoing TKA with CI. TXA usage in TKA is significantly beneficial in minimizing blood loss and regardless of instrumentation. When using TXA, the lowest blood loss was obtained in patients with higher BMI and submitted to TKA with CI. This is most likely explained by the synergistic antifibrotic effect of TXA with adipokines, such as plasminogen activator inhibitor-1 (PAI-1), found in the femoral bone marrow which is perforated using CI. If, however, TXA wasn't used, the lowest blood loss was obtained in patients submitted to TKA with PSI.

Revegetation of an area impacted by iron ore tailings: evaluating fertilization alternatives in native pioneer and secondary trees.

The iron ore tailings released into the Rio Doce basin after the Fundão dam collapse (Brazil), suppressed a large extent of local vegetation. The use of native species and appropriate fertilization techniques, with less economic and environmental impact, must be considered in the process for the restoration of affected areas by the tailings. For this purpose, six native tree species, pioneer (Anadenanthera colubrina, Bixa orellana, and Peltophorum dubium) and secondary (Cedrela fissilis, Handroanthus impetiginosus, and Handroanthus serratifolius), were selected. We used different conditions of fertilization: (1) inorganic fertilization, (2) inoculation with arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria, (3) combined treatment (fertilizer + inoculum), to evaluate leaf nutrient concentrations, photosynthetic capacity [chlorophyll index, maximum quantum efficiency of photosystem II (Fv/Fm) and gas exchange variables], and oxidative metabolism (H2O2, MDA, and antioxidant enzymes). Inoculation resulted in higher concentrations of foliar nitrogen, especially in pioneer species. In all treatments, the secondary species exhibited iron values considered phytotoxic, but showed reduced photosynthetic capacity only when inoculated. The highest concentrations of MDA were observed in inoculated plants of both successional groups. The antioxidant system proved to be effective in preventing oxidative damage for most of the species. These results showed that the use of inoculum can be considered an ecological alternative to inorganic additives in the area affected by iron ore tailings. Despite presenting different photosynthetic and antioxidant strategies, the evaluated species demonstrated potential for use in tailings revegetation projects.

Molecularly imprinted nanoparticle-based assay (MINA) for microcystin-LR detection in water.

Microcystins (MCs) are highly toxic peptides produced by cyanobacteria during algal blooms. Microcystin-leucine-arginine (MC-LR) is the most toxic and common MC variant with major effects on human and animal health upon exposure. MC-LR detection has become critical to ensure water safety, therefore robust and reliable analytical methods are needed. This work reports the development of a simple and optimized Molecularly Imprinted Nanoparticle-Based Assay (MINA) for MC-LR detection in water. Molecularly Imprinted Nanoparticles (MINs) were prepared by solid-phase polymerization on glass beads conjugated to MC-LR through (3-aminopropyl) triethoxysilane (APTES) via amide bonding. APTES-modified glass beads were obtained under optimized conditions to maximize the density of surface amino groups available for MC-LR conjugation. Two quinary mixtures of acrylic monomers differing in charge, polarity, and functionality were selected from molecular docking calculations and used to obtain MINs for MC-LR recognition using N,N'-methylene-bis-acrylamide (BIS) as the crosslinking agent. MINs were immobilized by physical adsorption onto 96-well polystyrene microplate and evaluated as per their rebinding capacity toward the analyte by using a covalent conjugate between MC-LR and the enzyme horseradish peroxidase (HRP). Experimental conditions for the MINs immobilization protocol, HRP-MC-LR concentration, and composition of the blocking solution were set to maximize the colorimetric response of the MINs compared to non-treated wells. Optimized conditions were then applied to conduct competitive MINAs with the HRP-MC-LR conjugate and the free analyte, which confirmed the preferential binding of MC-LR to the immobilized MINs for analyte concentrations ranging from 1 × 10-5 nmol L-1 to 100 nmol L-1. The best competitive MINA showed a limit of detection of 2.49 × 10-4 nmol L-1 and coefficients of variation less than 10% (n = 6), which are auspicious for the use of MINs as analytical tools for MC-LR detection below the permissible limits issued by WHO for safe water consumption (1.00 nmol L-1). This assay also proved to be selective to the analyte in cross-reactivity studies with two analogous microcystins (MC-RR and MC-YR). Analyses of lagoon and drinking water samples enriched with MC-LR revealed strong matrix effects that reduce the MINA response to the analyte, thus suggesting the need for sample pretreatment methods in future development in this subject.

Revegetation of mining-impacted sites with a tropical native grass: Constraints of climate seasonality and trace-element accumulation.

The iron ore mining activity results in considerable waste production and impacts on surrounding ecosystems. Natural recovery of impacted areas is absent or occurs slowly, especially when associated with prolonged dry seasons in tropical regions. The objective of this work was to unveil the mechanisms of Paspalum densum (Poir.) grass to overcome the periods of seasonal drought and its metal accumulation in areas impacted by iron mining, a tailings storage facilities and surrounding ferruginous grassland in Brazil. Lower mortality was observed among individuals in the tailings storage facilities, with a 74.3% survival rate. In contrast, after the beginning of the dry season, all individuals died in the ferruginous grassland. The plants in the tailings deposits showed better nutrition, with a higher concentration of P, Cu, Fe, Zn, Mn and greater capacity to accumulate Pb and Cd over time. Pb was the element with highest bioconcetration factor (BCF) and bioaccumulation coefficient (BAC), while Mn was the one with the highest translocation factor (TF). The dry season resulted in reduced chlorophyll a, b and total and effective quantum yield of photosystem II (PSII) of P. densum individuals. However, the plants in the tailings storage facilities showed adjustments to overcome the effects of drought, with an increase in the concentration of proline in leaves and reduction of oxidative damage (MDA and H2O2) at the end of the dry season. The grass P. densum showed rapid acclimatization in the tailings storage facilities and resistance to drought through antioxidant and photosynthetic adjustments and was still able to bioaccumulate and translocate in plant tissues some metals present in the iron ore impacted sites.

Diversity of responses to nitrogen deficiency in distinct wheat genotypes reveals the role of alternative electron flows in photoprotection.

Nitrogen (N) deficiency represents an important limiting factor affecting photosynthetic productivity and the yields of crop plants. Significant reported differences in N use efficiency between the crop species and genotypes provide a good background for the studies of diversity of photosynthetic and photoprotective responses associated with nitrogen deficiency. Using distinct wheat (Triticum aestivum L.) genotypes with previously observed contrasting responses to nitrogen nutrition (cv. Enola and cv. Slomer), we performed advanced analyses of CO2 assimilation, PSII, and PSI photochemistry, also focusing on the heterogeneity of the stress responses in the different leaf levels. Our results confirmed the loss of photosynthetic capacity and enhanced more in lower positions. Non-stomatal limitation of photosynthesis was well reflected by the changes in PSII and PSI photochemistry, including the parameters derived from the fast-fluorescence kinetics. Low photosynthesis in N-deprived leaves, especially in lower positions, was associated with a significant decrease in the activity of alternative electron flows. The exception was the cyclic electron flow around PSI that was enhanced in most of the samples with a low photosynthetic rate. We observed significant genotype-specific responses. An old genotype Slomer with a lower CO2 assimilation rate demonstrated enhanced alternative electron flow and photorespiration capacity. In contrast, a modern, highly productive genotype Enola responded to decreased photosynthesis by a significant increase in nonphotochemical dissipation and cyclic electron flow. Our results illustrate the importance of alternative electron flows for eliminating the excitation pressure at the PSII acceptor side. The decrease in capacity of electron acceptors was balanced by the structural and functional changes of the components of the electron transport chain, leading to a decline of linear electron transport to prevent the overreduction of the PSI acceptor side and related photooxidative damage of photosynthetic structures in leaves exposed to nitrogen deficiency.