Tangential velocity constraint for orbital maneuvers with Theory of Functional Connections.

Maneuvering a spacecraft in the cislunar space is a complex problem, since it is highly perturbed by the gravitational influence of both the Earth and the Moon, and possibly also the Sun. Trajectories minimizing the needed fuel are generally preferred in order to decrease the mass of the payload. A classical method to constrain maneuvers is mathematically modeling them using the Two Point Boundary Value Problem (TPBVP), defining spacecraft positions at the start and end of the trajectory. Solutions to this problem can then be obtained with optimization techniques like the nonlinear least squares conjugated with the Theory of Functional Connections (TFC) to embed the constraints, which recently became an effective method for deducing orbit transfers. In this paper, we propose a tangential velocity (TV) type of constraints to design orbital maneuvers. We show that the technique presented in this paper can be used to transfer a spacecraft (e.g. from the Earth to the Moon) and perform gravity assist maneuvers (e.g. a swing-by with the Moon). In comparison with the TPBVP, solving the TV constraints via TFC offers several advantages, leading to a significant reduction in computational time. Hence, it proves to be an efficient technique to design these maneuvers.

Denture Adhesives Associated with Silver Vanadate: Antimicrobial Approach Against Multi- Species Biofilms on Acrylic Resin Surfaces.

Alternatives have been sought to add an antimicrobial property to denture adhesives. This study evaluated the antimicrobial potential of adhesives associated with nanostructured silver vanadate decorated with silver nanoparticles (ß-AgVO3). Specimens in acrylic resin were treated with the adhesives associated with ß-AgVO3 (1%, 2.5%, 5% and 10%). As control, specimens treated only with Ultra Corega Cream (UCC) or Ultra Corega Powder (UCP) adhesive were used. Multispecies biofilm of Candida albicans, Candida glabrata, Streptococcus mutans and Staphylococcus aureus was evaluated by counting colony forming units per milliliter (CFU/mL), colorimetric assay and fluorescence microscopy. The data were analyzed using the two-way analysis of variance (ANOVA) and Bonferroni multiple comparisons test (α=0.05). For both adhesives, a small amount of ß-AgVO3 (1%) completely inhibited S. mutans (P⟨0.05). For the other microorganisms, there was a reduction in metabolic activity and complete inhibition in the groups with intermediate or greater amounts of nanomaterial (P⟨0.05), except for C. albicans, which was reduced (P⟨0.05) but not completely inhibited in UCP. Microscopy that showed less biofilm in the groups with ß-AgVO3 and in the UCC than UCP. Denture adhesives in powder and cream form with ß-AgVO3 showed potential antimicrobial activity against multispecies biofilm. Powder adhesive showed higher biofilm formation.

The impact of sputum quality on Xpert positivity in active case-finding for TB.

BACKGROUND: Studies evaluating sputum quality and Xpert® MTB/RIF positivity in the context of active case finding are scarce. We aimed to determine whether sputum quality is associated with Xpert positivity and whether the association differed according to demographic and clinical characteristics.METHODS: A cross-sectional analysis using data from a mass screening programme in Brazilian prisons was conducted from 2017 to 2021. We administered a standardised questionnaire, obtained a chest X-ray and collected a spot sputum sample for Xpert testing. Sputum quality was classified as 'salivary', 'mucoid/mucopurulent' or 'blood-stained'. We used log binomial regressions to estimate the relationship between sputum quality and Xpert positivity, assessing interactions with participant characteristics.RESULTS: Among 4,368 participants for whom sputum quality was assessed, 957 (21.9%) produced salivary specimens, 3,379 (77.4%) had mucoid/mucopurulent sputum and 32 (0.7%) had blood-stained sputum. Xpert positivity was higher among those with mucoid/mucopurulent sputum than among those with salivary samples (12.0% vs. 3.7%). Mucopurulent sputum independently predicted Xpert positivity among individuals with and without symptoms, current smoking and abnormal chest radiographs on CAD4TB.CONCLUSIONS: In our study, sputum appearance independently predicted Xpert positivity, and could be used together with chest X-ray and symptom screening to inform use of Xpert in individual or pooled testing.

Evaluating total nitrogen and phosphorous concentrations in a watershed impacted by diverse anthropic activities in a developing country.

This research aims to identify critical contamination points by nutrients, their possible origin (point and nonpoint sources), their spatial distribution, and possible attenuation by natural and anthropogenic processes. The study area is the Velhas River Basin, located in the Southeast Region of Brazil (17.0°-20.5° S; 43.5°-45.0°W). A historical series of water quality monitoring, land cover map, demographic and agricultural censuses, sewage treatment diagnostics, and local hydrographic networks were used to achieve the objectives. In addition, the regions were divided into incremental areas, enabling individualized analyses of each sub-basin. Descriptive statistics, seasonality, categorized data tests, agglomerative hierarchical cluster analysis, and principal component analysis were used. There was a significant contribution of nutrients in the most important urban agglomeration of the basin, resulting in peak concentrations measured at that place. Although the values were reduced by the mouth (650 km), the percentage of legislation violations remained high. The effects of punctual contamination were intensified by the low percentage of treated sewage in the basin, the absence of adequate treatment technologies to remove nutrients, and the disorderly urbanization. Furthermore, it was estimated that the nutrient load from animal husbandry is approximately 75% of the load from domestic effluents due to the high number of cattle in the basin and the low percentage of forests.

Impact of Compensating Curves on Mastication of Complete Denture Wearers: A Randomised Triple-Blind Clinical Trial.

INTRODUCTION: The application of occlusal concepts in prosthodontics is still under debate.This study assessed the impact of compensating curves on the comminution of complete denture wearers. METHODS: Seven edentulous subjects, aged 64.6 ± 2.0 years, were rehabilitated with new muco-supported complete dentures and tested in two occlusal plane settings: with and without compensating curves. A randomised triple-blind clinical trial was conducted, considering one-week and one-month as adaptation periods for dentures. After each trial, the subjects were crossed over to their respective groups. One-week was also chosen as the washout period, and after that, the subjects were re-examined. The masticatory performance and swallowing threshold were determined while chewing Optocal test food. The multiple sieve method was used for fractionation and granulometry. RESULTS: During the masticatory performance and swallowing threshold estimates, no differences were found between the median particle sizes obtained with the both occlusal plane conditions (P ⟩ 0.05). However, the swallowing threshold improved after one month, resulting in smaller particle sizes. Moreover, the chewing rates for the both test foods were also increased (P ⟨ 0.05). CONCLUSIONS: These findings suggest that the compensating curves did not have an impact on the masticatory function of subjects wearing complete dentures.

Irrigation with saline water in the cultivation of mini watermelon under phosphate fertilization.

The objective of this study was to evaluate the water status, photosynthetic pigments, and photochemical efficiency of mini watermelon plants under salt stress and phosphate fertilization. The experiment was conducted in pots under greenhouse conditions in Pombal, PB, Brazil. The experimental design used was randomized blocks in a 5 × 4 factorial scheme, with five levels of electrical conductivity of irrigation water - ECw (0.3, 1.3, 2.3, 3.3, and 4.3 dS m-1) and four doses of phosphorus (60, 80, 100, and 120% of the recommendation), with three replicates. The relative water content in the tissues decreased with the increase in ECw levels in all phosphorus doses, with decreases of 7.05, 7.81 and 8.83% per unit increase in ECw, in plants fertilized with 80, 100 and 120% P2O5. On the other hand, ECw levels increased electrolyte leakage, regardless of phosphorus doses of the recommendation. The synthesis of photosynthetic pigments and the quantum efficiency of photosystem II were inhibited by increasing water salinity from 0.3 dS m-1 in plants grown under phosphorus doses above 60% of the recommendation. Water salinity from 0.3 dS m-1 reduced chlorophyll b contents, initial, maximum, and variable fluorescence of mini watermelon plants, with a decrease of 11.86, 4.51, 4.53, and 4.54% per unit increment of ECw, respectively.

The effect of Zostera noltei recolonization on the sediment mercury vertical profiles of a recovering coastal lagoon.

Mercury's extreme toxicity and persistence in the environment justifies a thorough evaluation of its dynamics in ecosystems. Aveiro Lagoon (Portugal) was for decades subject to mercury effluent discharges. A Nature-based Solution (NbS) involving Zostera noltei re-colonization is being tested as an active ecosystem restoration measure. To study the effect of Zostera noltei on the sediment contaminant biogeochemistry, seasonal (summer/winter) sediment, interstitial water and labile mercury vertical profiles were made in vegetated (Transplanted and Natural seagrass meadows) and non-vegetated sites (Bare-bottom area). While no significant differences (p > 0.05) were observed in the sedimentary phase, Zostera noltei presence reduced the reactive/labile mercury concentrations in the top sediment layers by up to 40% when compared to non-vegetated sediment, regardless of season. No differences were found between vegetated meadows, highlighting the fast recovery of the contaminant regulation ecosystem function provided by the plants after re-colonization and its potential for the rehabilitation of historically contaminated ecosystems.

Salicylic acid does not relieve salt stress on gas exchange, chlorophyll fluorescence, and hydroponic melon growth.

The objective of this study was to evaluate the salicylic acid applications in attenuating the harmful effects of saline nutrient solution on the physiology and growth of 'Gaúcho' melon cultivated in the NFT hydroponic system. The experiment was conducted in a greenhouse, in Pombal-PB, Brazil. The cultivation system used was the Nutrient Film Technique - NFT hydroponics. A completely randomized split-plot design was used, with the plot referring to four levels of salinity in the nutrient solution - ECns (2.1 control, 3.2, 4.3, and 5.4 dS m-1) and the sub-plot four concentrations of salicylic acid (SA) (0, 1.5, 3.0, and 4.5 mM), applied via foliar spray, with six replications. Nutrient solution of 4.3 and 5.4 dS m-1 electrical conductivity promotes higher maximum and variable fluorescence, respectively. The stomatal conductance, transpiration, stem diameter, main branch length, leaf dry mass, and stem dry mass of 'Gaúcho' melon plants decrease with the increase in salinity of the nutrient solution. Salicylic acid increases the initial fluorescence and the main branch length of 'Gaúcho' melon plants in hydroponic cultivation. Salicylic acid at a concentration of 1.5 to 4.5 mM did not attenuate the effects of salt stress on the internal CO2 concentration, CO2 assimilation rate, and root dry mass of 'Gaúcho' melon plants.

A Study of Sponge Symbionts from Different Light Habitats.

The amount of available light plays a key role in the growth and development of microbial communities. In the present study, we tested to what extent sponge-associated prokaryotic communities differed between specimens of the sponge species Cinachyrella kuekenthali and Xestospongia muta collected in dimly lit (caves and at greater depths) versus illuminated (shallow water) habitats. In addition to this, we also collected samples of water, sediment, and another species of Cinachyrella, C. alloclada. Overall, the biotope (sponge host species, sediment, and seawater) proved the major driver of variation in prokaryotic community composition. The light habitat, however, also proved a predictor of compositional variation in prokaryotic communities of both C. kuekenthali and X. muta. We used an exploratory technique based on machine learning to identify features (classes, orders, and OTUs), which distinguished X. muta specimens sampled in dimly lit versus illuminated habitat. We found that the classes Alphaproteobacteria and Rhodothermia and orders Puniceispirillales, Rhodospirillales, Rhodobacterales, and Thalassobaculales were associated with specimens from illuminated, i.e., shallow water habitat, while the classes Dehalococcoidia, Spirochaetia, Entotheonellia, Nitrospiria, Schekmanbacteria, and Poribacteria, and orders Sneathiellales and Actinomarinales were associated with specimens sampled from dimly lit habitat. There was, however, considerable variation within the different light habitats highlighting the importance of other factors in structuring sponge-associated bacterial communities.

Identification of APOB variants in samples from the brazilian population with hypercholesterolemic phenotype

BACKGROUND AND AIMS: Apolipoprotein B plays a crucial role in regulating plasma cholesterol by mediating the interaction of low-density lipoprotein (LDL) with LDL receptors in the liver. Inherited mutations in this gene may increase the risk of developing premature atherosclerotic cardiovascular disease, especially in individuals with familial hypercholesterolemia type 2 (FH2). The aim of this study is to identify APOB variants that may indicate pathogenicity in a sample of the Brazilian population using a data bank exome sequencing study by NGS in a Brazilian population phenotypically diagnosed by clinical and laboratory profile. This finding is going to improve genetic hypercholesteremia diagnosis. METHODS: High-quality DNA samples (n»300) were sequenced using an exon-targeted gene sequencing (ETGS) strategy to identify variants in FHrelated genes. Pathogenicity classification was based on criteria established by the American College of Medical Genetics and Genomics (ACMG), also using information from ClinVar and pathogenicity scores from previous association studies. RESULTS: A total of 121 variants were identified in APOB, of which four are novel variants missense (p.Thr626Asn, p.Ile2750Thr, p.Gln2078Lys and p.Met4184Arg). After curating pathogenicity scores, variants were classified according to the ACMG criteria. Among them four as pathogenic or likely pathogenic (p.Pro2739Leu, p.His1923Arg, p.Pro994Leu and p.Pro877Leu), and 21 variants had uncertain significance. Additionally, 92 previously known variants with uncertain significance were classified as benign or likely benign. The results were submitted to Clinvar for actualization of pathogenicity. CONCLUSIONS: These results improve the molecular diagnosis associating APOB variants with the clinical phenotype of hypercholesterolemia.

Zostera noltei response to transplantation into historically Hg-contaminated sediments (A mesocosm experiment): Growth, bioaccumulation and photosynthetic performance.

The present study aimed to evaluate the effectiveness of seagrass recolonization as a nature-based solution for the recovery of a coastal area historically contaminated by mercury (Laranjo Bay, Ria de Aveiro, Portugal). A mesocosm approach was employed to assess the resistance of Zostera noltei to transplantation into contaminated sediments collected in-situ (0.5-20 mg kg-1 Hg). At each sampling time (15, 30, 60, 120 and 210 days), the resistance of transplanted Z. noltei was evaluated through growth parameters (biomass and coverage area), photosynthetic performance and elemental composition. Although some significant differences (p ≤ 0.05) were observed between treatments, essentially associated with the elemental composition of plant tissues, the most relevant variations were associated with seasonality. Overall, plants were found to not be affected by sediment contamination, under the tested concentrations, suggesting that recolonization with Z. noltei can be an effective restoration strategy for historically contaminated coastal areas.

Analysis of microbial communities of ocular prostheses and anophthalmic sockets using 16S rRNA gene sequencing.

Ocular prostheses are liable to host microbial adhesion, which can favor conjunctival inflammation. Knowing the microbiota of the ocular prosthesis and anophthalmic socket is important for predicting infection-related pathogens. This study evaluated the microbiota of the prostheses and anophthalmic sockets of six individuals by 16S rRNA sequencing. The microbial abundance and diversity were analyzed using the Operational Taxonomic Units at the genus level. Forty-seven phyla, capturing 1,258 named genera, were recorded in the sample set. In both sites, the most frequent genera were Fusobacterium, Staphylococcus, Prevotella, and Streptococcus. The microbial abundance was higher for the anophthalmic socket than for the prosthesis. Alpha diversity showed no significant differences in bacterial richness or diversity between sites. Although the microbial abundance in the anophthalmic socket was higher, both sites had similar microbiota with high diversity and low dominance among the genera.

Brain glucose hypometabolism and hippocampal inflammation in Goto-Kakizaki rats.

Brain glucose hypometabolism and neuroinflammation are early pathogenic manifestations in neurological disorders. Neuroinflammation may also disrupt leptin signaling, an adipokine that centrally regulates appetite and energy balance by acting on the hypothalamus and exerting neuroprotection in the hippocampus. The Goto-Kakizaki (GK) rat is a non-obese type 2 diabetes mellitus (T2DM) animal model used to investigate diabetes-associated molecular mechanisms without obesity jeopardizing effects. Wistar and GK rats received the maintenance adult rodent diet. Also, an additional control group of Wistar rats received a high-fat and high-sugar diet (HFHS) provided by free consumption of condensed milk. All diets and water were provided ad libitum for eight weeks. Brain glucose uptake was evaluated by 2-deoxy-2-[fluorine-18] fluoro-D-glucose under basal (saline administration) or stimulated (CL316,243, a selective ß3-AR agonist) conditions. The animals were fasted for 10-12 h, anesthetized, and euthanized. The brain was quickly dissected, and the hippocampal area was sectioned and stored at -80°C in different tubes for protein and RNA analyses on the same animal. GK rats exhibited attenuated brain glucose uptake compared to Wistar animals and the HFHS group under basal conditions. Also, the hippocampus of GK rats displayed upregulated leptin receptor, IL-1ß, and IL-6 gene expression and IL-1ß and the subunit of the transcription factor NF-κB (p-p65) protein expression. No significant alterations were detected in the hippocampus of HFHS rats. Our data indicated that a genetic predisposition to T2DM has significant brain deteriorating features, including brain glucose hypometabolism, neuroinflammation, and leptin signaling disruption in the hippocampal area.

Physiology and production of sugar-apple under water stress and application of proline.

The objective of this study was to evaluate the physiology and production of sugar-apple as a function of irrigation intervals and foliar application of proline under the conditions of Paraíba's semi-arid region. A randomized block design was laid out in a 4 × 2 factorial scheme, with treatments resulting from the combination of four irrigation intervals (1, 4, 8 and 12 days) and two concentrations of proline (0 and 10 mM), with four replicates, and the plot consisted of four usable plants. Increase in irrigation intervals reduced the gas exchange of sugar-apple plants at 298 days after transplanting. Exogenous application of proline at concentration of 10 mM increased contents of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids and fruit fresh mass in plants grown under 12-day irrigation intervals.

Pre-treatment with IL-6 potentiates ß-cell death induced by pro-inflammatory cytokines.

BACKGROUND: Type I Diabetes mellitus (T1D) is characterized by a specific destruction of ß-cells by the immune system. During this process pro-inflammatory cytokines are released in the pancreatic islets and contribute for ß-cells demise. Cytokine-induced iNOS activation, via NF-κB, is implicated in induction of ß-cells death, which includes ER stress activation. Physical exercise has been used as an adjunct for better glycemic control in patients with T1D, since it is able to increase glucose uptake independent of insulin. Recently, it was observed that the release of IL-6 by skeletal muscle, during physical exercise, could prevent ß-cells death induced by pro-inflammatory cytokines. However, the molecular mechanisms involved in this beneficial effect on ß-cells are not yet completely elucidated. Our aim was to evaluate the effect of IL-6 on ß-cells exposed to pro-inflammatory cytokines. RESULTS: Pre-treatment with IL-6 sensitized INS-1E cells to cytokine-induced cell death, increasing cytokine-induced iNOS and Caspase-3 expression. Under these conditions, however, there was a decrease in cytokines-induced p-eIF2-α but not p-IRE1expression, proteins related to ER stress. To address if this prevention of adequate UPR response is involved in the increase in ß-cells death markers induced by IL-6 pre-treatment, we used a chemical chaperone (TUDCA), which improves ER folding capacity. Use of TUDCA increased cytokines-induced Caspase-3 expression and Bax/Bcl-2 ratio in the presence of IL-6 pre-treatment. However, there is no modulation of p-eIF2-α expression by TUDCA in this condition, with increase of CHOP expression. CONCLUSION: Treatment with IL-6 alone is not beneficial for ß-cells, leading to increased cell death markers and impaired UPR activation. In addition, TUDCA has not been able to restore ER homeostasis or improve ß-cells viability under this condition, suggesting that other mechanisms may be involved.

A comparison of free-living and sponge-associated bacterial communities from a remote oceanic island with a focus on calcareous sponges.

Calcareous sponges are an often overlooked element of sponge communities. In contrast to most other sponges, calcareous sponges produce calcium carbonate spicules, as opposed to the siliceous spicules of most sponges. Here, we investigated the bacterial communities of 17 sponge species, including type and paratype specimens of recently described calcareous species, sampled off the remote island of Rodrigues, in the Indian Ocean. The main axis of variation in a PCO analysis of all samples separated noncalcareous sponge species, including Axinyssa aplysinoides, Cinachyrella aff. australiensis, Petrosia seychellensis, Ircinia aff. variabilis, Spongia ceylonensis, Plakinastrella aff. clipptertonensis, Agelas aff. ceylonica, Agelas aff. mauritiana, and Hyrtios erectus from calcareous sponges, the noncalcareous Biemna tubulata, sediment, and seawater. Overall, the bacterial communities of calcareous sponges revealed unique prokaryotic profiles with low abundances of several bacterial phyla, and relatively high abundances of other taxa, for example, the phyla Fibrobacterota, Proteobacteria, and the SAR324 clade, the class Alphaproteobacteria, and orders Cytophagales and Cyanobacteriales, although there was considerable variation among species. Calcareous sponges also had a high dominance of unknown bacterial operational taxonomic units (OTUs). Considering the unique nature of these communities, further studies are needed to better understand the environmental and ecological drivers of calcareous sponge-associated bacterial communities and their relevance as potential sources of novel microbes of biotechnological interest.

Brain glucose hypometabolism and hippocampal inflammation in Goto-Kakizaki rats

Brain glucose hypometabolism and neuroinflammation are early pathogenic manifestations in neurological disorders. Neuroinflammation may also disrupt leptin signaling, an adipokine that centrally regulates appetite and energy balance by acting on the hypothalamus and exerting neuroprotection in the hippocampus. The Goto-Kakizaki (GK) rat is a non-obese type 2 diabetes mellitus (T2DM) animal model used to investigate diabetes-associated molecular mechanisms without obesity jeopardizing effects. Wistar and GK rats received the maintenance adult rodent diet. Also, an additional control group of Wistar rats received a high-fat and high-sugar diet (HFHS) provided by free consumption of condensed milk. All diets and water were provided ad libitum for eight weeks. Brain glucose uptake was evaluated by 2-deoxy-2-[fluorine-18] fluoro-D-glucose under basal (saline administration) or stimulated (CL316,243, a selective β3-AR agonist) conditions. The animals were fasted for 10-12 h, anesthetized, and euthanized. The brain was quickly dissected, and the hippocampal area was sectioned and stored at -80°C in different tubes for protein and RNA analyses on the same animal. GK rats exhibited attenuated brain glucose uptake compared to Wistar animals and the HFHS group under basal conditions. Also, the hippocampus of GK rats displayed upregulated leptin receptor, IL-1β, and IL-6 gene expression and IL-1β and the subunit of the transcription factor NF-κB (p-p65) protein expression. No significant alterations were detected in the hippocampus of HFHS rats. Our data indicated that a genetic predisposition to T2DM has significant brain deteriorating features, including brain glucose hypometabolism, neuroinflammation, and leptin signaling disruption in the hippocampal area.

Brain glucose hypometabolism and hippocampal inflammation in Goto-Kakizaki rats

Brain glucose hypometabolism and neuroinflammation are early pathogenic manifestations in neurological disorders. Neuroinflammation may also disrupt leptin signaling, an adipokine that centrally regulates appetite and energy balance by acting on the hypothalamus and exerting neuroprotection in the hippocampus. The Goto-Kakizaki (GK) rat is a non-obese type 2 diabetes mellitus (T2DM) animal model used to investigate diabetes-associated molecular mechanisms without obesity jeopardizing effects. Wistar and GK rats received the maintenance adult rodent diet. Also, an additional control group of Wistar rats received a high-fat and high-sugar diet (HFHS) provided by free consumption of condensed milk. All diets and water were provided ad libitum for eight weeks. Brain glucose uptake was evaluated by 2-deoxy-2-[fluorine-18] fluoro-D-glucose under basal (saline administration) or stimulated (CL316,243, a selective β3-AR agonist) conditions. The animals were fasted for 10-12 h, anesthetized, and euthanized. The brain was quickly dissected, and the hippocampal area was sectioned and stored at -80°C in different tubes for protein and RNA analyses on the same animal. GK rats exhibited attenuated brain glucose uptake compared to Wistar animals and the HFHS group under basal conditions. Also, the hippocampus of GK rats displayed upregulated leptin receptor, IL-1β, and IL-6 gene expression and IL-1β and the subunit of the transcription factor NF-κB (p-p65) protein expression. No significant alterations were detected in the hippocampus of HFHS rats. Our data indicated that a genetic predisposition to T2DM has significant brain deteriorating features, including brain glucose hypometabolism, neuroinflammation, and leptin signaling disruption in the hippocampal area.

In vitro study of the modulatory effects of heat-killed bacterial biomass on aquaculture bacterioplankton communities.

Recent studies have shown that the addition of non-viable microbial biomass or their components (postbiotics) to fish feed can modulate the gut microbiome and positively influence fish health in aquaculture systems. However, no information was hitherto available on the use of non-viable microbial biomass to manipulate aquaculture bacterioplankton communities. To fill this gap, here we used an in vitro model to assess the effects of heat-killed biomasses of an antagonistic strain Pseudoalteromonas rubra SubTr2 and a non-antagonist strain Escherichia coli DH5α on bacterioplankton communities of a recirculating aquaculture system (RAS). Our results showed that these biomasses can have generalist and species-specific effects on aquaculture bacterioplankton structure and function. In addition, they enriched the abundance of bacterial predators, reduced bacterial load and potentially influenced nutrient cycling and pathogen development in aquaculture water. Despite its preliminary nature, for the first time, this study showed that heat-killed microbial biomass has potential application as an in situ modulator of bacterioplankton in aquaculture systems.

Salicylic acid does not mitigate salt stress on the morphophysiology and production of hydroponic melon.

The excess of salts present in the water can limit the hydroponic cultivation of melon in semi-arid regions of the Brazilian Northeast, making it necessary to use strategies that allow the use of these waters. Among these strategies, the use of elicitor substances stands out, such as salicylic acid. In this context, this study aimed to evaluate the effect of foliar application of salicylic acid in mitigating the harmful effects of salt stress on the morphophysiology and production of 'Gaúcho' melon cultivated in a hydroponic system. A completely randomized design was adopted in a split-plot scheme, with four levels of electrical conductivity of the nutrient solution - ECsn (2.1, 3.2, 4.3, and 5.4 dS m-1) considered the plots and four salicylic acid concentrations - SA (0, 1.5, 3.0, and 4.5 mM), the subplots, with six replications. The foliar application of salicylic acid concentrations did not mitigate the deleterious effects of salt stress on the morphophysiology and yield of melon grown in hydroponic system. The concentration of 4.5 mM of salicylic acid intensified the harmful effects of the salinity of the nutrient solution on gas exchange and fresh weight of hydroponic melon.