Analysis of Plasma Proteins Involved in Inflammation, Immune Response/Complement System, and Blood Coagulation upon Admission of COVID-19 Patients to Hospital May Help to Predict the Prognosis of the Disease.

The development of new approaches allowing for the early assessment of COVID-19 cases that are likely to become critical and the discovery of new therapeutic targets are urgently required. In this prospective cohort study, we performed proteomic and laboratory profiling of plasma from 163 COVID-19 patients admitted to Bauru State Hospital (Brazil) between 4 May 2020 and 4 July 2020. Plasma samples were collected upon admission for routine laboratory analyses and shotgun quantitative label-free proteomics. Based on the course of the disease, the patients were divided into three groups: (a) mild (n = 76) and (b) severe (n = 56) symptoms, whose patients were discharged without or with admission to an intensive care unit (ICU), respectively, and (c) critical (n = 31), a group consisting of patients who died after admission to an ICU. Based on our data, potential therapies for COVID-19 should target proteins involved in inflammation, the immune response and complement system, and blood coagulation. Other proteins that could potentially be employed in therapies against COVID-19 but that so far have not been associated with the disease are CD5L, VDBP, A1BG, C4BPA, PGLYRP2, SERPINC1, and APOH. Targeting these proteins' pathways might constitute potential new therapies or biomarkers of prognosis of the disease.

Magnesium-enriched poultry manure enhances phosphorus bioavailability in biochars.

Pyrolysis of calcium-rich feedstock (e.g., poultry manure) generates semi-crystalline and crystalline phosphorus (P) species, compromising its short-term availability to plants. However, enriching poultry manure with magnesium (Mg) before pyrolysis may improve the ability of biochar to supply P. This study investigated how increasing the Mg/Ca ratio and pyrolysis temperature of poultry manure affected its P availability and speciation. Mg enrichment by ∼2.1% increased P availability (extracted using 2% citric and formic acid) by 20% in Mg-biochar at pyrolysis temperatures up to 600 °C. Linear combination fitting of P K-edge XANES of biochar, and Mg/Ca stoichiometry, indicate that P species, mainly Ca-P and Mg-P, are altered after pyrolysis. At 300 °C, adding Mg as magnesium hydroxide [Mg(OH)2] created MgNH4PO4 (18%) and Mg3(PO4)2.8H2O (23%) in the biochar, while without addition of Mg Ca3(PO4)2 (11%) predominated, both differing only for pyrophosphate, 33 and 16%, respectively. Similarly, the P L2,3 edge XANES data of biochar made with Mg were indicative of either MgHPO4.3H2O or Mg3(PO4)2.8H2O, in comparison to CaHPO4.2H2O or Ca3(PO4)2 without Mg. More importantly, hydroxyapatite [Ca5(PO4)3(OH)] was not identified with Mg additions, while it was abundant in biochars produced without Mg both at 600 (12%) and 700 °C (32%). The presence of Mg formed Mg-P minerals that could enhance P mobility in soil more than Ca-P, and may have resulted in greater P availability in Mg-enriched biochars. Thus, a relatively low Mg enrichment can be an approach for designing and optimize biochar as a P fertilizer from P-rich excreta, with the potential to improve P availability and contribute to the sustainable use of organic residues.

Sulfate supply decreases barium availability, uptake, and toxicity in lettuce plants grown in a tropical Ba-contaminated soil.

Barium (Ba) is a non-essential element that can cause toxicity in living organisms and environmental contamination. Plants absorb barium predominantly in its divalent cationic form Ba2+. Sulfur (S) can decrease the availability of Ba2+ in the soil by causing its precipitation as barium sulfate, a compound known for its very low solubility. The objective of this study was to evaluate the effect of soil sulfate supply in soil Ba fractions, as well as on plant growth, and Ba and S uptake by lettuce plants grown in artificially Ba-contaminated soil under greenhouse conditions. The treatments consisted of five Ba doses (0, 150, 300, 450, and 600 mg kg-1 Ba, as barium chloride) combined with three S doses (0, 40, and 80 mg kg-1 S, as potassium sulfate). The treatments were applied to soil samples (2.5 kg) and placed in plastic pots for plant cultivation. The Ba fractions analyzed were extractable-Ba, organic matter-Ba, oxides associated-Ba, and residual-Ba. The results indicate that the extractable-Ba fraction was the main one responsible for Ba bioavailability and phytotoxicity, probably corresponding to the exchangeable Ba in the soil. The dose of 80 mg kg-1 of S reduced extractable-Ba by 30% at higher Ba doses while it increased the other fractions. Furthermore, S supply attenuated the growth inhibition in plants under Ba exposure. Thus, S supply protected the lettuce plants from Ba toxicity by reduction of Ba availability in soil and plant growth enhancement. The results suggest that sulfate supply is a suitable strategy for managing Ba-contaminated areas.

Multi-omics Investigation into the Mechanism of Action of an Anti-tubercular Fatty Acid Analogue.

The mechanism of action (MoA) of a clickable fatty acid analogue 8-(2-cyclobuten-1-yl)octanoic acid (DA-CB) has been investigated for the first time. Proteomics, metabolomics, and lipidomics were combined with a network analysis to investigate the MoA of DA-CB against Mycobacterium smegmatis (Msm). The metabolomics results showed that DA-CB has a general MoA related to that of ethionamide (ETH), a mycolic acid inhibitor that targets enoyl-ACP reductase (InhA), but DA-CB likely inhibits a step downstream from InhA. Our combined multi-omics approach showed that DA-CB appears to disrupt the pathway leading to the biosynthesis of mycolic acids, an essential mycobacterial fatty acid for both Msm and Mycobacterium tuberculosis (Mtb). DA-CB decreased keto-meromycolic acid biosynthesis. This intermediate is essential in the formation of mature mycolic acid, which is a key component of the mycobacterial cell wall in a process that is catalyzed by the essential polyketide synthase Pks13 and the associated ligase FadD32. The multi-omics analysis revealed further collateral alterations in bacterial metabolism, including the overproduction of shorter carbon chain hydroxy fatty acids and branched chain fatty acids, alterations in pyrimidine metabolism, and a predominate downregulation of proteins involved in fatty acid biosynthesis. Overall, the results with DA-CB suggest the exploration of this and related compounds as a new class of tuberculosis (TB) therapeutics. Furthermore, the clickable nature of DA-CB may be leveraged to trace the cellular fate of the modified fatty acid or any derived metabolite or biosynthetic intermediate.

Leveraging the Structure of DNAJA1 to Discover Novel Potential Pancreatic Cancer Therapies.

Pancreatic cancer remains one of the deadliest forms of cancer with a 5-year survival rate of only 11%. Difficult diagnosis and limited treatment options are the major causes of the poor outcome for pancreatic cancer. The human protein DNAJA1 has been proposed as a potential therapeutic target for pancreatic cancer, but its cellular and biological functions remain unclear. Previous studies have suggested that DNAJA1's cellular activity may be dependent upon its protein binding partners. To further investigate this assertion, the first 107 amino acid structures of DNAJA1 were solved by NMR, which includes the classical J-domain and its associated linker region that is proposed to be vital to DNAJA1 functionality. The DNAJA1 NMR structure was then used to identify both protein and ligand binding sites and potential binding partners that may suggest the intracellular roles of DNAJA1. Virtual drug screenings followed by NMR and isothermal titration calorimetry identified 5 drug-like compounds that bind to two different sites on DNAJA1. A pull-down assay identified 8 potentially novel protein binding partners of DNAJA1. These proteins in conjunction with our previously published metabolomics study support a vital role for DNAJA1 in cellular oncogenesis and pancreatic cancer.

Detection of Intestinal Dysbiosis in Post-COVID-19 Patients One to Eight Months after Acute Disease Resolution.

The intestinal microbiota plays an important role in the immune response against viral infections, modulating both innate and adaptive immune responses. The cytokine storm is associated with COVID-19 severity, and the patient's immune status is influenced by the intestinal microbiota in a gut-lung bidirectional interaction. In this study, we evaluate the intestinal microbiota of Brazilian patients in different post-COVID-19 periods, and correlate this with clinical data and the antibiotic therapy used during the acute phase. DNA extracted from stool samples was sequenced and total anti-SARS-CoV-2 antibodies and C-reactive protein were quantified. Compared with controls, there were significant differences in the microbiota diversity in post-COVID-19 patients, suggesting an intestinal dysbiosis even several months after acute disease resolution. Additionally, we detected some genera possibly associated with the post-COVID-19 dysbiosis, including Desulfovibrio, Haemophillus, Dialister, and Prevotella, in addition to decreased beneficial microbes, associated with antibiotic-induced dysbiosis, such as Bifidobacterium and Akkermansia. Therefore, our hypothesis is that dysbiosis and the indiscriminate use of antibiotics during the pandemic may be associated with post-COVID-19 clinical manifestations. In our study, 39% (n = 58) of patients reported symptoms, including fatigue, dyspnea, myalgia, alopecia, anxiety, memory loss, and depression. These data suggest that microbiota modulation may represent a target for recovery from acute COVID-19 and a therapeutic approach for post-COVID-19 sequelae.

Peptidomics analysis reveals changes in small urinary peptides in patients with interstitial cystitis/bladder pain syndrome.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic and debilitating pain disorder of the bladder and urinary tract with poorly understood etiology. A definitive diagnosis of IC/BPS can be challenging because many symptoms are shared with other urological disorders. An analysis of urine presents an attractive and non-invasive resource for monitoring and diagnosing IC/BPS. The antiproliferative factor (APF) peptide has been previously identified in the urine of IC/BPS patients and is a proposed biomarker for the disorder. Nevertheless, other small urinary peptides have remained uninvestigated in IC/BPS primarily because protein biomarker discovery efforts employ protocols that remove small endogenous peptides. The purpose of this study is to investigate the profile of endogenous peptides in IC/BPS patient urine, with the goal of identifying putative peptide biomarkers. Here, a non-targeted peptidomics analysis of urine samples collected from IC/BPS patients were compared to urine samples from asymptomatic controls. Our results show a general increase in the abundance of urinary peptides in IC/BPS patients, which is consistent with an increase in inflammation and protease activity characteristic of this disorder. In total, 71 peptides generated from 39 different proteins were found to be significantly altered in IC/BPS. Five urinary peptides with high variable importance in projection (VIP) coefficients were found to reliably differentiate IC/BPS from healthy controls by receiver operating characteristic (ROC) analysis. In parallel, we also developed a targeted multiple reaction monitoring method to quantify the relative abundance of the APF peptide from patient urine samples. Although the APF peptide was found in moderately higher abundance in IC/BPS relative to control urine, our results show that the APF peptide was inconsistently present in urine, suggesting that its utility as a sole biomarker of IC/BPS may be limited. Overall, our results revealed new insights into the profile of urinary peptides in IC/BPS that will aid in future biomarker discovery and validation efforts.

Effects of long-term fluoride exposure are associated with oxidative biochemistry impairment and global proteomic modulation, but not genotoxicity, in parotid glands of mice.

BACKGROUND: Fluoride has become widely used in dentistry because of its effectiveness in caries control. However, evidence indicates that excessive intake interferes with the metabolic processes of different tissues. Thus, this study aimed to investigate the effects of long-term exposure to F on the parotid salivary gland of mice, from the analysis of oxidative, proteomic and genotoxic parameters. MATERIALS AND METHODS: The animals received deionized water containing 0, 10 or 50 mg/L of F, as sodium fluoride, for 60 days. After, parotid glands were collected for analysis of oxidative biochemistry, global proteomic profile, genotoxicity assessment and histopathological analyses. RESULTS: The results revealed that exposure to fluoride interfered in the biochemical homeostasis of the parotid gland, with increased levels of thiobarbituric acid reactive species and reduced glutathione in the exposed groups; as well as promoted alteration of the glandular proteomic profile in these groups, especially in structural proteins and proteins related to oxidative stress. However, genotoxic assessment demonstrated that exposure to fluoride did not interfere with DNA integrity in these concentrations and durations of exposure. Also, it was not observed histopathological alterations in parotid gland. CONCLUSIONS: Thus, our results suggest that long-term exposure to fluoride promoted modulation of the proteomic and biochemical profile in the parotid glands, without inducing damage to the genetic component. These findings reinforce the importance of rationalizing the use of fluorides to maximize their preventative effects while minimizing the environmental risks.

New Insights into the Mechanism of Action of the Cyclopalladated Complex (CP2) in Leishmania: Calcium Dysregulation, Mitochondrial Dysfunction, and Cell Death.

The current treatment of leishmaniasis is based on a few drugs that present several drawbacks, such as high toxicity, difficult administration route, and low efficacy. These disadvantages raise the necessity to develop novel antileishmanial compounds allied with a comprehensive understanding of their mechanisms of action. Here, we elucidate the probable mechanism of action of the antileishmanial binuclear cyclopalladated complex [Pd(dmba)(µ-N3)]2 (CP2) in Leishmania amazonensis. CP2 causes oxidative stress in the parasite, resulting in disruption of mitochondrial Ca2+ homeostasis, cell cycle arrest at the S-phase, increasing the reactive oxygen species (ROS) production and overexpression of stress-related and cell detoxification proteins, and collapsing the Leishmania mitochondrial membrane potential, and promotes apoptotic-like features in promastigotes, leading to necrosis, or directs programmed cell death (PCD)-committed cells toward necrotic-like destruction. Moreover, CP2 reduces the parasite load in both liver and spleen in Leishmania infantum-infected hamsters when treated for 15 days with 1.5 mg/kg body weight/day CP2, expanding its potential application in addition to the already known effectiveness on cutaneous leishmaniasis for the treatment of visceral leishmaniasis, showing the broad spectrum of action of this cyclopalladated complex. The data presented here bring new insights into the CP2 molecular mechanisms of action, assisting the promotion of its rational modification to improve both safety and efficacy.

Radiotherapy changes the salivary proteome in head and neck cancer patients: evaluation before, during, and after treatment.

OBJECTIVES: Salivary glands are affected during radiotherapy in the head and neck region, leading to a reduction in salivary flow and changes its composition. Besides negatively affecting the oral soft tissues, this can also lead to dental impairment. Thus, we evaluated the effect of radiotherapy in the proteomic profile of the saliva in patients with head and neck cancer (HNC). MATERIALS AND METHODS: HNC patients had their saliva collected before (BRT), during (2-5 weeks; DRT), and after (3-4 months; ART) radiotherapy. Saliva was also collected from healthy volunteers (control; C). Samples were processed for proteomic analysis. RESULTS: In total, 1055 proteins were identified, among which 46 were common to all groups, while 86, 86, 286, and 395 were exclusively found in C, BRT, DRT, and ART, respectively. Remarkably, alpha-enolase was increased 35-fold DRT compared with BRT, while proline-rich proteins were decreased. ART there was a 16-fold increase in scaffold attachment factor-B1 and a 3-fold decrease in alpha-enolase and several cystatins. When compared with C, salivary proteins of BRT patients showed increases cystatin-C, lysozyme C, histatin-1, and proline-rich proteins CONCLUSION/CLINICAL REVELANCE: Both HNC and radiotherapy remarkably change the salivary protein composition. Altogether, our results, for the first time, suggest investigating alpha-enolase levels in saliva DRT in future studies as a possible biomarker and strategy to predict the efficiency of the treatment. Moreover, our data provide important insights for designing dental products that are more effective for these patients and contribute to a better understanding of the progressive changes in salivary proteins induced by radiotherapy. Graphical abstract.

A reversed phase ultra-high-performance liquid chromatography-data independent mass spectrometry method for the rapid identification of mycobacterial lipids.

A rapid reversed-phase ultra-high-performance liquid chromatography-high resolution mass spectrometry based mycobacterial lipidomics approach is described. This method enables the separation of various lipid classes including lipids specific to mycobacterial, such as methoxy mycolic acid and α-mycolic acid. Lipid separation occurs during a relatively short runtime of 14 min on a charged surface hybrid C18 column. A high-resolution quadrupole-time of flight mass spectrometer and a data independent acquisition mode allowed for the simultaneous acquisition of the full scan and collision induced dissociation fragmentation. The proposed method provides lipid detection results equivalent to or better than existing methods, but with a faster throughput and an overall higher sensitivity. The reversed-phase ultra-high-performance liquid chromatography-high resolution mass spectrometry method was shown to obtain structural information for lipids extracted from Mycobacterium smegmatis, but the method is applicable to the analysis of lipids from various bacterial and mammalian cell lines.

Effects of Fluoride on Submandibular Glands of Mice: Changes in Oxidative Biochemistry, Proteomic Profile, and Genotoxicity.

Although fluoride (F) is well-known to prevent dental caries, changes in cell processes in different tissues have been associated with its excessive exposure. Thus, this study aimed to evaluate the effects of F exposure on biochemical, proteomic, and genotoxic parameters of submandibular glands. Twenty one old rats (n = 30) were allocated into three groups: 60 days administration of drinking water containing 10 mgF/L, 50 mgF/L, or only deionized water (control). The submandibular glands were collected for oxidative biochemistry, protein expression profile, and genotoxic potential analyses. The results showed that both F concentrations increased the levels of thiobarbituric acid-reactive substances (TBARS) and reduced glutathione (GSH) and changed the proteomic profile, mainly regarding the cytoskeleton and cellular activity. Only the exposure to 50 mgF/L induced significant changes in DNA integrity. These findings reinforce the importance of continuous monitoring of F concentration in drinking water and the need for strategies to minimize F intake from other sources to obtain maximum preventive/therapeutic effects and avoid potential adverse effects.

Radiation exposure induces cross-species temporal metabolic changes that are mitigated in mice by amifostine.

Exposure to acute, damaging radiation may occur through a variety of events from cancer therapy and industrial accidents to terrorist attacks and military actions. Our understanding of how to protect individuals and mitigate the effects of radiation injury or Acute Radiation Syndrome (ARS) is still limited. There are only a few Food and Drug Administration-approved therapies for ARS; whereas, amifostine is limited to treating low dose (0.7-6 Gy) radiation poisoning arising from cancer radiotherapy. An early intervention is critical to treat ARS, which necessitates identifying diagnostic biomarkers to quickly characterize radiation exposure. Towards this end, a multiplatform metabolomics study was performed to comprehensively characterize the temporal changes in metabolite levels from mice and non-human primate serum samples following γ-irradiation. The metabolomic signature of amifostine was also evaluated in mice as a model for radioprotection. The NMR and mass spectrometry metabolomics analysis identified 23 dysregulated pathways resulting from the radiation exposure. These metabolomic alterations exhibited distinct trajectories within glucose metabolism, phospholipid biosynthesis, and nucleotide metabolism. A return to baseline levels with amifostine treatment occurred for these pathways within a week of radiation exposure. Together, our data suggests a unique physiological change that is independent of radiation dose or species. Furthermore, a metabolic signature of radioprotection was observed through the use of amifostine prophylaxis of ARS.

Outer Membrane Vesicle-Mediated Codelivery of the Antifungal HSAF Metabolites and Lytic Polysaccharide Monooxygenase in the Predatory Lysobacter enzymogenes.

Lysobacter are new biocontrol agents known for their prolific production of lytic enzymes and bioactive metabolites. L. enzymogenes is a predator of fungi and produces several structurally distinct antimicrobial compounds, such as the antifungal HSAF (heat stable antifungal factor) and analogs. The mechanism by which L. enzymogenes interacts with fungal prey is not well understood. Here, we found that the production of HSAF and analogs in L. enzymogenes OH11 was significantly induced in media supplemented with ground fungal mycelia or chitin. In the OH11 genome, we identified a gene (LeLPMO10A) that was annotated to encode a chitin-binding protein. The stimulation of HSAF and analogs by chitin was diminished when LeLPMO10A was deleted. We expressed the gene in E. coli and demonstrated that purified LeLPMO10A oxidatively cleaved chitin into oligomeric products, including 1,5 δ-lactones and aldonic acids. The results revealed that LeLPMO10A encodes a lytic polysaccharide monooxygenase, which has not been reported in Lysobacter. The metabolite analysis, antifungal assay, and proteomic analysis showed that the antifungal compounds and the chitin-cleaving LeLPMO10A are colocalized in outer membrane vesicles. The enzymatic products that resulted from in vitro LeLPMO10A-cleaved chitin also significantly induced HSAF and analogs in OH11. Scanning electron microscopic analysis indicated that spherical vesicles were formed outside of OH11 cells, and fewer OH11 cells were observed to attach to fungal hyphae when LeLPMO10A was deleted. Together, the study revealed a previously uncharacterized synergistic strategy utilized by the predatory Lysobacter during interaction with fungal prey.

Is there difference in the comparative and quantitative salivary proteome between stimulated and unstimulated saliva in head and neck cancer patients treated by radiotherapy?

Stimulation of saliva production is an alternative to improve the quality of life of patients treated by radiotherapy. However, there is no information about changes in the salivary proteome of stimulated and unstimulated saliva in these patients. OBJECTIVES: Thus, we evaluated the difference in the proteomic profile of stimulated and unstimulated saliva in patients with head and neck cancer (HNC) treated by radiotherapy. METHODS: Stimulated and unstimulated saliva were collected from 9 patients with HNC before (BRT), during (DRT; 2-5 weeks) and after (ART; 3-4 months) treatment. Healthy patients paired by age and gender also had their saliva collected (C; control group). The stimulated and unstimulated salivary flow were evaluated (p < 0.05). Salivary proteins were extracted and processed for shotgun proteomic analysis. RESULTS: Significant differences were observed between stimulated and unstimulated salivary flows for C and BRT (p greater than 0.001), but not for DRT and ART. Proteins involved with apoptosis, antibacterial and acid-resistance were decreased in stimulated saliva in comparison to unstimulated saliva DRT and ART. Isoforms of keratins were not identified in control and BRT. CONCLUSION: there is a marked difference in the protein profile of stimulated and unstimulated salivary flows in HNC patients treated by radiotherapy. In addition, saliva stimulation in patients with HNC decreases important proteins involved with dental protection. The unstimulated salivary flow seems to be the best alternative to search for biomarkers. Our results contribute in an unprecedented way to understand the changes in the salivary proteome of different flows in HNC patients undergoing radiotherapy treatment.

Detection of Dysbiosis and Increased Intestinal Permeability in Brazilian Patients with Relapsing-Remitting Multiple Sclerosis.

Dysbiosis, associated with barrier disruption and altered gut-brain communications, has been associated with multiple sclerosis (MS). In this study, we evaluated the gut microbiota in relapsing-remitting patients (RRMS) receiving disease-modifying therapies (DMTs) and correlated these data with diet, cytokines levels, and zonulin concentrations. Stool samples were used for 16S sequencing and real-time PCR. Serum was used for cytokine determination by flow cytometry, and zonulin quantification by ELISA. Pearson's chi-square, Mann-Whitney, and Spearman's correlation were used for statistical analyses. We detected differences in dietary habits, as well as in the gut microbiota in RRMS patients, with predominance of Akkermansia muciniphila and Bacteroides vulgatus and decreased Bifidobacterium. Interleukin-6 concentrations were decreased in treated patients, and we detected an increased intestinal permeability in RRMS patients when compared with controls. We conclude that diet plays an important role in the composition of the gut microbiota, and intestinal dysbiosis, detected in RRMS patients could be involved in increased intestinal permeability and affect the clinical response to DTMs. The future goal is to predict therapeutic responses based on individual microbiome analyses (personalized medicine) and propose dietary interventions and the use of probiotics or other microbiota modulators as adjuvant therapy to enhance the therapeutic efficacy of DMTs.

Global Proteomic Profile Integrated to Quantitative and Morphometric Assessment of Enteric Neurons: Investigation of the Mechanisms Involved in the Toxicity Induced by Acute Fluoride Exposure in the Duodenum.

The enteric nervous system is responsible for controlling the gastrointestinal tract (GIT) functions. Enteric neuropathies are highly correlated to the development of several intestinal disturbances. Fluoride (F) is extensively applied for dental health improvement and its ingestion can promote systemic toxicity with mild to severe GIT symptomatology and neurotoxicity. Although F harmful effects have been published, there is no information regarding noxiousness of a high acute F exposure (25 mg F/kg) on enteric neurons and levels of expression of intestinal proteins in the duodenum. Quantitative proteomics of the duodenum wall associated to morphometric and quantitative analysis of enteric neurons displayed F effects of a high acute exposure. F-induced myenteric neuroplasticity was characterized by a decrease in the density of nitrergic neurons and morphometric alterations in the general populations of neurons, nitrergic neurons, and substance P varicosities. Proteomics demonstrated F-induced alterations in levels of expression of 356 proteins correlated to striated muscle cell differentiation; generation of precursor metabolites and energy; NADH and glutathione metabolic process and purine ribonucleoside triphosphate biosynthesis. The neurochemical role of several intestinal proteins was discussed specially related to the modulation of enteric neuroplasticity. The results provide a new perspective on cell signaling pathways of gastrointestinal symptomatology promoted by acute F toxicity.

Hippocampal Impairment Triggered by Long-Term Lead Exposure from Adolescence to Adulthood in Rats: Insights from Molecular to Functional Levels.

Lead (Pb) is an environmental and occupational neurotoxicant after long-term exposure. This study aimed to investigate the effects of systemic Pb exposure in rats from adolescence to adulthood, evaluating molecular, morphologic and functional aspects of hippocampus. For this, male Wistar rats were exposed to 50 mg/kg of Pb acetate or distilled water for 55 days by intragastric gavage. For the evaluation of short-term and long-term memories, object recognition and step-down inhibitory avoidance tests were performed. At the end of the behavioral tests, the animals were euthanized and the hippocampus dissected and processed to the evaluation of: Pb content levels in hippocampal parenchyma; Trolox equivalent antioxidant capacity (TEAC), glutathione (GSH) and malondialdehyde (MDA) levels as parameters of oxidative stress and antioxidant status; global proteomic profile and neuronal degeneration by anti-NeuN immunohistochemistry analysis. Our results show the increase of Pb levels in the hippocampus of adult rats exposed from adolescence, increased MDA and GSH levels, modulation of proteins related to neural structure and physiology and reduced density of neurons, hence a poor cognitive performance on short and long-term memories. Then, the long-term exposure to Pb in this period of life may impair several biologic organizational levels of the hippocampal structure associated with functional damages.

Effects of acute fluoride exposure on the jejunum and ileum of rats: Insights from proteomic and enteric innervation analysis.

Fluoride (F) is largely employed in dentistry, in therapeutic doses, to control caries. However, excessive intake may lead to adverse effects in the body. Since F is absorbed mostly from the gastrointestinal tract (GIT), gastrointestinal symptoms are the first signs following acute F exposure. Nevertheless, little is known about the mechanistic events that lead to these symptoms. Therefore, the present study evaluated changes in the proteomic profile as well as morphological changes in the jejunum and ileum of rats upon acute exposure to F. Male rats received, by gastric gavage, a single dose of F containing 0 (control) or 25 mg/Kg for 30 days. Upon exposure to F, there was a decrease in the thickness of the tunic muscularis for both segments and a decrease in the thickness of the wall only for the ileum. In addition, a decrease in the density of HuC/D-IR neurons and nNOS-IR neurons was found for the jejunum, but for the ileum only nNOS-IR neurons were decreased upon F exposure. Moreover, SP-IR varicosities were increased in both segments, while VIP-IR varicosities were increased in the jejunum and decreased in the ileum. As for the proteomic analysis, the proteins with altered expression were mostly negatively regulated and associated mainly with protein synthesis and energy metabolism. Proteomics also revealed alterations in proteins involved in oxidative/antioxidant defense, apoptosis and as well as in cytoskeletal proteins. Our results, when analyzed together, suggest that the gastrointestinal symptoms found in cases of acute F exposure might be related to the morphological alterations in the gut (decrease in the thickness of the tunica muscularis) that, at the molecular level, can be explained by alterations in the gut vipergic innervation and in proteins that regulate the cytoskeleton.

Aging of biochar-based fertilizers in soil: Effects on phosphorus pools and availability to Urochloa brizantha grass.

Water-soluble phosphate fertilizers release phosphorus (P) to soils promptly, causing P fixation and low plant availability in highly weathered tropical soils. Therefore, the development of strategies to improve P use efficiency is needed. We hypothesized that biochar-based fertilizers (BBFs) can provide available P to plants and improve P use efficiency when compared with soluble fertilizers. Thus, triple superphosphate (TSP) and phosphoric acid (H3PO4) were pyrolyzed with and without magnesium oxide (MgO) and poultry litter to produce slow-release P BBFs. A pot experiment under greenhouse conditions was performed to evaluate agronomic efficiency of BBFs compared with TSP in an Oxisol. The treatments were incubated over 100 days after the application of 25, 50, 100, and 200 mg kg-1 of P. Three controls were used, including 200 mg kg-1 of P as TSP incubated for 100 days (named TSPincubation) and applied immediately before sowing (named TSPplanting) and a negative control (without P). Marandu grass (Urochloa brizantha cv. Marandu) was cultivated in pots for three cycles of 40 days each. After cultivation, a sequential extraction procedure was used to determine the P distribution among different P pools. The shoot dry matter yield in the first cropping cycle was higher at the highest P rate for TSPplanting. PLB-H3PO4-MgO showed 9% increase in the shoot dry matter when compared with TSPincubation in the first cropping cycle. In subsequent cropping cycles, all BBFs promoted higher biomass yield when compared with TSPplanting. There was an increase in the labile and moderately labile P fractions in soil after cultivation with PLB-TSP. The results suggest that BBFs can enhance P use efficiency in tropical soils in the middle- to long-term run due to slow-release profile that prevent P fixation and promote higher residual effect of fertilization.