Generation Of Metabolic Energy Research Articles

Sensitive monitoring of NAD(P)H levels within cancer cells using mitochondria-targeted near-infrared cyanine dyes with optimized electron-withdrawing acceptors.

A series of near-infrared fluorescent probes, labeled A to E, were developed by combining electron-rich thiophene and 3,4-ethylenedioxythiophene bridges with 3-quinolinium and various electron deficient groups, enabling the sensing of NAD(P)H. Probes A and B exhibit absorptions and emissions in the near-infrared range, offering advantages such as minimal interference from autofluorescence, negligible photo impairment in cells and tissues, and exceptional tissue penetration. These probes show negligible fluorescence when NADH is not present, and their absorption maxima are at 438 nm and 470 nm, respectively. In contrast, probes C-E feature absorption maxima at 450, 334 and 581 nm, respectively. Added NADH triggers the transformation of the electron-deficient 3-quinolinium units into electron-rich 1,4-dihydroquinoline units resulting in fluorescence responses which were established at 748, 730, 575, 625 and 661 for probes AH-EH, respectively, at detection limits of 0.15 μM and 0.07 μM for probes A and B, respectively. Optimized geometries based on theoretical calculations reveal non-planar geometries for probes A-E due to twisting of the 3-quinolinium and benzothiazolium units bonded to the central thiophene group, which all attain planarity upon addition of hydride resulting in absorption and fluorescence in the near-IR region for probes AH and BH in contrast to probes CH-EH which depict fluorescence in the visible range. Probe A has been successfully employed to monitor NAD(P)H levels in glycolysis and specific mitochondrial targeting. Furthermore, it has been used to assess the influence of lactate and pyruvate on the levels of NAD(P)H, to explore how hypoxia in cancer cells can elevate levels of NAD(P)H, and to visualize changes in levels of NAD(P)H under hypoxic conditions with CoCl2 treatment. Additionally, probe A has facilitated the examination of the potential impact of chemotherapy drugs, namely gemcitabine, camptothecin, and cisplatin, on metabolic processes and energy generation within cancer cells by affecting NAD(P)H levels. Treatment of A549 cancer cells with these drugs has been shown to increase NAD(P)H levels, which may contribute to their anticancer effects ultimately leading to programmed cell death or apoptosis. Moreover, probe A has been successfully employed in monitoring NAD(P)H level changes in D. melanogaster larvae treated with cisplatin.

Recovery capability of anaerobic digestion from ammonia stress: Metabolic activity, energy generation, and genome-centric metagenomics

Excessive ammonia stresses anaerobic digestion (AD) significantly. Although there has been progress in understanding AD under ammonia exposure, investigations on AD liberated from ammonia exposure are limited. Here, the recovery capability of AD from ammonia stress was evaluated, by examining specific methanogenic activity, energy-conserving capability, microbial community succession, and metabolic pathway reconstruction. The findings demonstrated that ammonia stress relief resulted in < 50% methane recovery, with propionate conversion identified as the critical impediment to AD reactivation. Energy generation could not recovered either. Efforts to mitigate ammonia stress failed to restore acetoclastic methanogens, e.g., Methanothrix soehngenii, and proved futile in awakening propionate oxidizers, e.g., Desulfobulbus. Interestingly, a symbiotic metabolism emerged, prevailing in stress-relieved AD due to its energy-conserving advantage. This study underscores the importance of targeted interventions, including stimulating acetoclastic methanogenesis, propionate oxidation, and energy generation, as priorities for AD recovery following ammonia stress, rather than focusing solely on ammonia level management.

Benzoic Acid Inclusion Effects on Health Status and Growth Performance of Juvenile Pacific White Shrimp Penaeus vannamei

AbstractOrganic acids and their salts are used as additives in aquafeeds, as their participation in some metabolic pathways and energy generation in organisms increases the nutritional value. Benzoic acid (BA; C6H5‐COOH), a white crystalline substance with a chemical structure that contains carboxylic acid attached to a benzene ring, is naturally found in plant and animal tissues. It is one of the most used organic acids due to its antifungal properties, and it acts as a preservative for a variety of human consumption products. Additionally, it demonstrates health and growth benefits when included in feeds by modifying the energy metabolism, microbiota, and intestinal tract morphology. Information on BA inclusion in aquatic food is rare, and such information for Pacific white shrimp Penaeus vannamei is nonexistent. This study evaluated the effects on growth, survival, feed conversion ratio, energy content, and health status (through lipid quantification in the hepatopancreas, histological examination, and salinity stress tests) of Pacific white shrimp juveniles by including BA at different concentrations (0.0, 1.0, 1.5, and 2.0 g/kg) in a commercial feed. Diets with BA inclusion produced significant differences in the hepatosomatic index, hepatopancreas lipid content, and histopathological index value (reflecting damage to the hepatopancreas and antennal gland atrophy) at all BA concentrations. The lowest survival obtained was 94.44% at a BA concentration of 1.0 g/kg. The feed conversion ratio was in accordance with the range established by the Food and Agriculture Organization of the United Nations except for values obtained at 0 g/kg. Calorimetric analysis and BA detection in muscle revealed no significant differences between concentrations. Due to the results obtained in this study, the evaluated inclusions of BA are not recommended for use in juvenile Pacific white shrimp diets.

Significance of serum levels of magnesium, phosphorus, and calcium in hypertensive patients

Background: Hypertension also known as high blood pressure is one of the most common complex and public health problems which become more prevalent in developed and developing countries. Epidemiological studies have found links between high blood pressure and age, sex, race, geographic location, local industrialization level, lifestyle, nutrition, and work. Macro and microelements are known to play a major role in various enzyme reactions directly related to the regulation of blood pressure and indirectly related to generation of oxidative metabolic energy and alterations in blood lipid levels. Disturbances in these elements composition may therefore play a major role in the development and management of essential hypertension. The changes in plasma magnesium, calcium, and phosphorus level in hypertensive patients should therefore be actively investigated. The findings of this study may help to understand the effects of elements in the regulation of blood pressure. Aims and Objectives: The aims of this study were to measure the levels of trace elements (Serum magnesium, phosphorus, and calcium) in patients of hypertension. Materials and Methods: Serum magnesium, phosphorus, and calcium were estimated in 50 hypertensive patients and 50 age-and sex-matched apparently healthy well-nourished controls by colorimetric method using Erba XL 640 fully autoanalyzer. Results: Mean serum magnesium, serum phosphorus, and serum calcium were significantly reduced in hypertensive patients than control group. Conclusion: Hypertension is asymptomatic condition, whereby the patient’s blood pressure measurement is greater than 140/90 mmHg1. The causes of high blood pressure vary. It may be due to smoking of cigarettes, alcoholism, and narrowing of arteries. Diet definitely plays a crucial role in the development of hypertension along with stress. The relationship between trace elements and cardiovascular diseases, including high blood pressure, has been the subject of many investigations over the past 40–50 years. It is believed that mineral imbalance may significantly contribute to the development and course of hypertension. Mean serum magnesium, mean serum phosphorus, and mean serum calcium were significantly reduced, while serum copper was significantly higher in hypertensive patient than control group.

Contrasting Sodium and Potassium Perturbations in the Hippocampus Indicate Potential Na+/K+-ATPase Dysfunction in Vascular Dementia.

Vascular dementia (VaD) is thought to be the second most common cause of age-related dementia amongst the elderly. However, at present, there are no available disease-modifying therapies for VaD, probably due to insufficient understanding about the molecular basis of the disease. While the notion of metal dyshomeostasis in various age-related dementias has gained considerable attention in recent years, there remains little comparable investigation in VaD. To address this evident gap, we employed inductively coupled-plasma mass spectrometry to measure the concentrations of nine essential metals in both dry- and wet-weight hippocampal post-mortem tissue from cases with VaD (n = 10) and age-/sex-matched controls (n = 10). We also applied principal component analysis to compare the metallomic pattern of VaD in the hippocampus with our previous hippocampal metal datasets for Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, and type-2 diabetes, which had been measured using the same methodology. We found substantive novel evidence for elevated hippocampal Na levels and Na/K ratios in both wet- and dry-weight analyses, whereas decreased K levels were present only in wet tissue. Multivariate analysis revealed no distinguishable hippocampal differences in metal-evoked patterns between these dementia-causing diseases in this study. Contrasting levels of Na and K in hippocampal VaD tissue may suggest dysfunction of the Na+/K+-exchanging ATPase (EC 7.2.2.13), possibly stemming from deficient metabolic energy (ATP) generation. These findings therefore highlight the potential diagnostic importance of cerebral sodium measurement in VaD patients.

Cryptosporidium parvum Pyruvate Kinase Inhibitors With in vivo Anti-cryptosporidial Efficacy.

Cryptosporidium parvum is a highly prevalent protozoan parasite that causes a diarrheal disease in humans and animals worldwide. Thus far, the moderately effective nitazoxanide is the only drug approved by the United States Food and Drug Administration for treating cryptosporidiosis in immunocompetent humans. However, no effective drug exists for the severe disease seen in young children, immunocompromised individuals and neonatal livestock. C. parvum lacks the Krebs cycle and the oxidative phosphorylation steps, making it dependent solely on glycolysis for metabolic energy production. Within its glycolytic pathway, C. parvum possesses two unique enzymes, the bacterial-type lactate dehydrogenase (CpLDH) and the plant-like pyruvate kinase (CpPyK), that catalyze two sequential steps for generation of essential metabolic energy. We have previously reported that inhibitors of CpLDH are effective against C. parvum, both in vitro and in vivo. Herein, we developed an in vitro assay for the enzymatic activity of recombinant CpPyK protein and used it to screen a chemical compound library for inhibitors of CpPyK’s activity. The identified inhibitors were tested (at non-toxic concentrations) for efficacy against C. parvum using in vitro assays, and an in vivo mouse infection model. We identified six CpPyK inhibitors that blocked in vitro growth and proliferation of C. parvum at low micromolar concentrations (EC50 values ranging from 10.29 to 86.01 μM) that were non-toxic to host cells. Among those six compounds, two (NSC252172 and NSC234945) were found to be highly efficacious against cryptosporidiosis in immunocompromised mice at a dose of 10 mg/kg body weight, with very significant reduction in parasite load and amelioration of intestinal pathologies. Together, these findings have unveiled inhibitors for an essential molecular target in C. parvum and demonstrated their efficacy against the parasite in vitro and in vivo. These inhibitors are, therefore, potential lead-compounds for developing efficacious treatments for cryptosporidiosis.

Role of PKM2-Mediated Immunometabolic Reprogramming on Development of Cytokine Storm.

The cytokine storm is a marker of severity of various diseases and increased mortality. The altered metabolic profile and energy generation of immune cells affects their activation, exacerbating the cytokine storm. Currently, the emerging field of immunometabolism has highlighted the importance of specific metabolic pathways in immune regulation. The glycolytic enzyme pyruvate kinase M2 (PKM2) is a key regulator of immunometabolism and bridges metabolic and inflammatory dysfunction. This enzyme changes its conformation thus walks in different fields including metabolism and inflammation and associates with various transcription factors. This review summarizes the vital role of PKM2 in mediating immunometabolic reprogramming and its role in inducing cytokine storm, with a focus on providing references for further understanding of its pathological functions and for proposing new targets for the treatment of related diseases.

Analytical Investigation of Non-Fourier Bioheat Transfer in the Axisymmetric Living Tissue Exposed to Pulsed Laser Heating Using Finite Integral Transform Technique

Abstract This article proposes the closed-form solution of the generalized non-Fourier model-based bioheat transfer equation (BHTE) in Cylindrical coordinates to understand the thermal behavior of living tissue heated by a pulsed laser. The axisymmetric living tissue exposed to the non-Gaussian temporal profile of laser heating has been considered to investigate the non-Fourier bioheat transfer phenomena. The closed-form solution of the generalized non-Fourier model-based BHTE with time-dependent thermal energy generation has been obtained through the finite integral transform (FIT) technique. The analytical solution was juxtaposed to the corresponding numerical solution in order to determine its reliability. The numerical solution of the aforementioned governing equation has been obtained by the finite volume method (FVM). The results of both analytical and numerical solutions have been verified using results given in published literature. Subsequently, the dual-phase-lag (DPL) model's findings were juxtaposed to those obtained using the hyperbolic and traditional Fourier models. The effect of different parameters like relaxation times corresponding to the temperature gradient and heat flux, metabolic energy generation, and blood perfusion on the resultant temperature distribution inside the axisymmetric living tissue exposed to pulsed laser heating has been discussed. The importance of this study might be found in various applications such as laser-based-photothermal therapy, melting of the surface of metal and alloys by laser heating.

OseIF3h Regulates Plant Growth and Pollen Development at Translational Level Presumably through Interaction with OsMTA2.

The initiation stage of protein biosynthesis is a sophisticated process tightly regulated by numerous initiation factors and their associated components. However, the mechanism underlying translation initiation has not been completely understood in rice. Here, we showed knock-out mutation of the rice eukaryotic translation initiation factor 3 subunit h (OseIF3h) resulted in plant growth retardation and seed-setting rate reduction as compared to the wild type. Further investigation demonstrated an interaction between OseIF3h and OsMTA2 (mRNA adenosine methylase 2), a rice homolog of METTL3 (methyltransferase-like 3) in mammals, which provided new insight into how N6-methyladenosine (m6A) modification of messenger RNA (mRNA) is engaged in the translation initiation process in monocot species. Moreover, the RIP-seq (RNA immunoprecipitation sequencing) data suggested that OseIF3h was involved in multiple biological processes, including photosynthesis, cellular metabolic process, precursor metabolites, and energy generation. Therefore, we infer that OseIF3h interacts with OsMTA2 to target a particular subset of genes at translational level, regulating plant growth and pollen development.

Metabolic dysfunction and immunometabolism in COVID-19 pathophysiology and therapeutics.

The COVID-19 pandemic has emerged as a public health crisis and has placed a significant burden on healthcare systems. Patients with underlying metabolic dysfunction, such as type 2 diabetes mellitus and obesity, are at a higher risk for COVID-19 complications, including multi-organ dysfunction, secondary to a deranged immune response, and cellular energy deprivation. These patients are at a baseline state of chronic inflammation associated with increased susceptibility to the severe immune manifestations of COVID-19, which are triggered by the cellular hypoxic environment and cytokine storm. The altered metabolic profile and energy generation of immune cells affect their activation, exacerbating the imbalanced immune response. Key immunometabolic interactions may inform the development of an efficacious treatment for COVID-19. Novel therapeutic approaches with repurposed drugs, such as PPAR agonists, or newly developed molecules such as the antagomirs, which block microRNA function, have shown promising results. Those treatments, alone or in combination, target both immune and metabolic pathways and are ideal for septic COVID-19 patients with an underlying metabolic condition.

The Weathering Microbiome of an Outcropping Granodiorite.

Microorganisms have long been recognized for their capacity to catalyze the weathering of silicate minerals. While the vast majority of studies on microbially mediated silicate weathering focus on organotrophic metabolism linked to nutrient acquisition, it has been recently demonstrated that chemolithotrophic ferrous iron [Fe(II)] oxidizing bacteria (FeOB) are capable of coupling the oxidation of silicate mineral Fe(II) to metabolic energy generation and cellular growth. In natural systems, complex microbial consortia with diverse metabolic capabilities can exist and interact to influence the biogeochemical cycling of essential elements, including iron. Here we combine microbiological and metagenomic analyses to investigate the potential interactions among metabolically diverse microorganisms in the near surface weathering of an outcrop of the Rio Blanco Quartz Diorite (DIO) in the Luquillo Mountains of Puerto Rico. Laboratory based incubations utilizing ground DIO as metabolic energy source for chemolithotrophic FeOB confirmed the ability of FeOB to grow via the oxidation of silicate-bound Fe(II). Dramatically accelerated rates of Fe(II)-oxidation were associated with an enrichment in microorganisms with the genetic capacity for iron oxidizing extracellular electron transfer (EET) pathways. Microbially oxidized DIO displayed an enhanced susceptibility to the weathering activity of organotrophic microorganisms compared to unoxidized mineral suspensions. Our results suggest that chemolithotrophic and organotrophic microorganisms are likely to coexist and contribute synergistically to the overall weathering of the in situ bedrock outcrop.

Expanded roles of pyruvate-sensing PdhR in transcription regulation of the Escherichia coli K-12 genome: fatty acid catabolism and cell motility.

The transcription factor PdhR has been recognized as the master regulator of the pyruvate catabolism pathway in Escherichia coli , including both NAD-linked oxidative decarboxylation of pyruvate to acetyl-CoA by PDHc (pyruvate dehydrogenase complex) and respiratory electron transport of NADH to oxygen by Ndh-CyoABCD enzymes. To identify the whole set of regulatory targets under the control of pyruvate-sensing PdhR, we performed genomic SELEX (gSELEX) screening in vitro. A total of 35 PdhR-binding sites were identified along the E. coli K-12 genome, including previously identified targets. Possible involvement of PdhR in regulation of the newly identified target genes was analysed in detail by gel shift assay, RT-qPCR and Northern blot analysis. The results indicated the participation of PdhR in positive regulation of fatty acid degradation genes and negative regulation of cell mobility genes. In fact, GC analysis indicated an increase in free fatty acids in the mutant lacking PdhR. We propose that PdhR is a bifunctional global regulator for control of a total of 16–23 targets, including not only the genes involved in central carbon metabolism but also some genes for the surrounding pyruvate-sensing cellular pathways such as fatty acid degradation and flagella formation. The activity of PdhR is controlled by pyruvate, the key node between a wide variety of metabolic pathways, including generation of metabolic energy and cell building blocks.

Removal of tri-(2-chloroisopropyl) phosphate (TCPP) by three types of constructed wetlands

In this study, three types of constructed wetlands (CWs) (biofilm-attachment-surface-CWs, packed bed-CWs and traditional-CWs) were assembled to comparatively evaluate their ability and mechanism to remove tri-(2-chloroisopropyl) phosphate (TCPP) under continuous flow operation. The removal rate (26%–28%) of TCPP in two types of CWs containing plants was twice as much as that in plant-free CWs in 6-month experiments, and TCPP showed a terminal accumulation phenomenon in Cyperus alternifolius with the order of accumulation of leaf>stem>root. The mass balance indicated that the contributions of filler and hydrophyte absorption to TCPP removal were less than 1%, but the transpiration of hydrophytes may make an important contribution (approximately 10%) to TCPP removal. Species in the genera Massilia, Denitratisoma and SM1A02 may be responsible for TCPP biodegradation. In addition, the effect of TCPP on the metabolic pathways and energy generation in the roots of C. alternifolius suggested that TCPP may be transported and utilized through cellular metabolism.

Enzymology of the pathway for ATP production by arginine breakdown.

In cells, the breakdown of arginine to ornithine and ammonium ion plus carbon dioxide is coupled to the generation of metabolic energy in the form of ATP. The arginine breakdown pathway is minimally composed of arginine deiminase, ornithine transcarbamoylase, carbamate kinase, and an arginine/ornithine antiporter; ammonia and carbon dioxide most likely diffuse passively across the membrane. The genes for the enzymes and transporter have been cloned and expressed, and the proteins have been purified from Lactococcus lactis IL1403 and incorporated into lipid vesicles for sustained production of ATP. Here, we study the kinetic parameters and biochemical properties of the individual enzymes and the antiporter, and we determine how the physicochemical conditions, effector composition, and effector concentration affect the enzymes. We report the K M and V MAX values for catalysis and the native oligomeric state of all proteins, and we measured the effect of pathway intermediates, pH, temperature, freeze–thaw cycles, and salts on the activity of the cytosolic enzymes. We also present data on the protein‐to‐lipid ratio and lipid composition dependence of the antiporter.

Heterogeneity in respiratory electron transfer and adaptive iron utilization in a bacterial biofilm

In Bacillus subtilis, robust biofilm formation requires large quantities of ferric iron. Here we show that this process requires preferential production of a siderophore precursor, 2,3-dihydroxybenzoate, instead of the siderophore bacillibactin. A large proportion of iron is associated extracellularly with the biofilm matrix. The biofilms are conductive, with extracellular iron potentially acting as electron acceptor. A relatively small proportion of ferric iron is internalized and boosts production of iron-containing enzymes involved in respiratory electron transfer and establishing strong membrane potential, which is key to biofilm matrix production. Our study highlights metabolic diversity and versatile energy generation strategies within B. subtilis biofilms.

Evidence for the Accumulation of 3‐Hydroxypropionate and β‐Alanine in Arabidopsis thaliana Seedlings via Isoleucine Degradation

Amino acids serve several cellular processes outside of proteinogenesis that influence the growth and development of the plant, as well as the generation of metabolic energy. Here, we examine the contribution of branched‐chain amino acid degradation to the production of β‐alanine in the model organism, Arabidopsis thaliana. β‐alanine is a key intermediate in the synthesis of the essential molecules vitamin B5 and coenzyme A (CoA). Despite the importance, the current knowledge surrounding β‐alanine lacks strong evidence for the primary biosynthetic pathways in higher plants. Previous studies found that polyamines, uracil, and propionate can all serve as sources for β‐alanine. Given that the catabolism of branched‐chain amino acids (BCAAs) valine and isoleucine result in the production of propionyl‐CoA (a derivative of propionate), we hypothesized that these BCAAs could also serve as a source of β‐alanine. Propionyl‐CoA is typically converted to acetyl‐CoA via β‐oxidation, however, one of the intermediates, malonate semialdehyde, can react to form β‐alanine. To trace the production of β‐alanine from propionyl‐CoA and the BCAA isoleucine, we treated wild‐type and transgenic seedlings with isotopically‐labeled precursors and analyzed extracts using 13C‐NMR and GC‐MS. We observed the production of both β‐alanine and a key intermediate, 3‐hydroxypropionate (3HP) in samples treated with propionate and isoleucine. Our data shows that the fed 13C‐isotopes were efficiently incorporated into and recycled through propionyl‐CoA metabolism, resulting in the production of 13C‐labeled β‐alanine. These findings suggest that while there is evidence for the production of β‐alanine via polyamines, uracil, and propionate in other plants; isoleucine, and possibly valine, can also serve as a precursor to this metabolically important molecule.Support or Funding InformationClare Boothe Luce Undergraduate Scholars program funded by the Henry Luce Foundation (Grant #9601)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The mitochondrial DNA copy number used as biomarker

Mitochondria are organelles of eukaryotic cells which are responsible for the generation of metabolic energy The mitochondrial matrix contains the mitochondrial genome a molecule of circular DNA with base pairs containing genes that encode proteins tRNAs and rRNAs Each mitochondrion can have dozens of copies of its mitochondrial DNA depending on the cell type However variations in the mitochondrial DNA copy number have been associated with different pathological states including cancer and environmental exposure to some pollutants Consequently the mitochondrial DNA content represents a useful early biomarker to monitor premature changes in metabolic disorders due to external factors such as environmental pollutants or diseases Therefore in this minireview the way to measure the mitochondrial DNA copy number by PCR as well as some relevant epidemiological studies are summarized

Hippocampal Proteomic Analysis Reveals Distinct Pathway Deregulation Profiles at Early and Late Stages in a Rat Model of Alzheimer's-Like Amyloid Pathology.

The cerebral accumulation and cytotoxicity of amyloid beta (Aβ) is central to Alzheimer's pathogenesis. However, little is known about how the amyloid pathology affects the global expression of brain proteins at different disease stages. In order to identify genotype and time-dependent significant changes in protein expression, we employed quantitative proteomics analysis of hippocampal tissue from the McGill-R-Thy1-APP rat model of Alzheimer-like amyloid pathology. McGill transgenic rats were compared to wild-type rats at early and late pathology stages, i.e., when intraneuronal Aβ amyloid burden is conspicuous and when extracellular amyloid plaques are abundant with more pronounced cognitive deficits. After correction for multiple testing, the expression levels of 64 proteins were found to be considerably different in transgenic versus wild-type rats at the pre-plaque stage (3months), and 86 proteins in the post-plaque group (12months), with only 9 differentially regulated proteins common to the 2 time-points. This minimal overlap supports the hypothesis that different molecular pathways are affected in the hippocampus at early and late stages of the amyloid pathology throughout its continuum. At early stages, disturbances in pathways related to cellular responses to stress, protein homeostasis, and neuronal structure are predominant, while disturbances in metabolic energy generation dominate at later stages. These results shed new light on the molecular pathways affected by the early accumulation of Aβ and how the evolving amyloid pathology impacts other complex metabolic pathways.

Identification of antigenic proteins in Strongyloides stercoralis by proteomic analysis.

Strongyloides stercoralis is an intestinal helminth that infects people worldwide. Hyperinfection or disseminated human strongyloidiasis can involve vital organs, leading to lethal outcomes. We analyzed immunoproteomics of antigenic spots, derived from S. stercoralis third-stage larvae and reacted with human strongyloidiasis sera, by two-dimensional gel electrophoresis and immunoblotting. Of 26 excised antigenic spots analyzed by liquid chromatography-electrospray ionization-tandem mass spectrometry, 20 proteins were identified. Most proteins were associated with enzymes involved in the metabolic process, energy generation, and oxidation-reduction. The proteins relate to promotion of worm development, cell division, cell signaling and transportation, and regulation of muscular contraction. Identification of antigenic proteins shows promise in helping to discover potential diagnostic protein markers or vaccine candidates for S. stercoralis infection.

The Involvement of Nitric Oxide in Integration of Plant Physiological and Ultrastructural Adjustments in Response to Arsenic.

High arsenic (As) concentrations are toxic to all the living organisms and the cellular response to this metalloid requires the involvement of cell signaling agents, such as nitric oxide (NO). The As toxicity and NO signaling were analyzed in Pistia stratiotes leaves. Plants were exposed to four treatments, for 24 h: control; SNP [sodium nitroprusside (NO donor); 0.1 mg L-1]; As (1.5 mg L-1) and As + SNP (1.5 and 0.1 mg L-1, respectively). The absorption of As increased the concentration of reactive oxygen species and triggered changes in the primary metabolism of the plants. While photosynthesis and photorespiration showed sharp decrease, the respiration process increased, probably due to chemical similarity between arsenate and phosphate, which compromised the energy status of the cell. These harmful effects were reflected in the cellular structure of P. stratiotes, leading to the disruption of the cells and a possible programmed cell death. The damages were attenuated by NO, which was able to integrate central plant physiological processes, with increases in non-photochemical quenching and respiration rates, while the photorespiration level decreased. The increase in respiratory rates was essential to achieve cellular homeostasis by the generation of carbon skeletons and metabolic energy to support processes involved in responses to stress, as well to maintaining the structure of organelles and prevent cell death. Overall, our results provide an integrated view of plant metabolism in response to As, focusing on the central role of NO as a signaling agent able to change the whole plant physiology.