Different behavior of food-related benzoic acids toward iron and copper.

Benzoic acids, which are commonly found in food, are also produced by human microbiota from other dietary phenolics. The aim was to investigate the interactions of 8 food-related benzoic acids with the physiological metals iron and copper under different (patho)physiologically relevant pH conditions in terms of chelation, reduction, impact on the metal-based Fenton chemistry, and copper-based hemolysis. Only 3,4-dihydroxybenzoic acid behaved as a protective substance under all conditions. It chelated iron, reduced both iron and copper, and protected against the iron and copper-based Fenton reaction. Conversely, 2,4,6-trihydroxybenzoic acid did not chelate iron and copper, reduced both metals, potentiated the Fenton reaction, and worsened copper-based hemolysis of rat red blood cells. The other tested compounds showed variable effects on the Fenton reaction. Interestingly, prooxidative benzoic acids mildly protected human erythrocytes against Cu-induced lysis. In conclusion, 3,4-dihydroxybenzoic acid seems to have a protective effect against copper and iron-based toxicity under different conditions.

Plexus-Specific Retinal Capillary Blood Flow Analysis Using Erythrocyte Mediated Angiography and Optical Coherence Tomography Angiography.

Purpose: The purpose of this study was to identify and measure plexus-specific absolute retinal capillary blood flow velocity and acceleration in vivo in both nonhuman primates (NHPs) and humans using erythrocyte mediated angiography (EMA) and optical coherence tomography angiography (OCTA). Methods: EMA and OCTA scans centered on the fovea were obtained in 2 NHPs and 11 human subjects. Scans were also obtained in NHP eyes while IOP was experimentally elevated. Erythrocyte velocity and acceleration in retinal arteries, capillaries, and veins were measured and capillaries were categorized based on location within the superficial vascular (SVP), intermediate capillary (ICP), or deep capillary plexus (DCP). Generalized linear mixed models were used to estimate the effects of intraocular pressure (IOP) on capillary blood flow. Results: Capillary erythrocyte velocity at baseline IOP was 0.64 ± 0.29 mm/s in NHPs (range of 0.14 to 1.85 mm/s) and 1.55 ± 0.65 mm/s in humans (range of 0.46 to 4.50 mm/s). Mean erythrocyte velocity in the SVP, ICP, and DCP in NHPs was 0.69 ± 0.29 mm/s, 0.53 ± 0.22 mm/s, and 0.63 ± 0.27 mm/s, respectively (P = 0.14 for NHP-1 and P = 0.28 for NHP-2). Mean erythrocyte velocity in the human subjects did not differ significantly among SVP, ICP, and DCP (1.46 ± 0.59 mm/s, 1.58 ± 0.55 mm/s, and 1.59 ± 0.79 mm/s, P = 0.36). In NHPs, every 1 mm Hg increase in IOP was associated with a 0.13 mm/s reduction in arterial velocity, 0.10 mm/s reduction in venous velocity, and 0.01 mm/s reduction in capillary velocity (P < 0.001) when accounting for differences in mean arterial pressure (MAP). Conclusions: Blood flow by direct visualization of individual erythrocytes can be quantified within capillary plexuses. Capillary velocity decreased with experimental IOP elevation.

Analysis of Erythrocyte Parameters in Multiple and Long-Term Blood Donors from Northern Pomerania (Poland).

BACKGROUND/AIMS: Assessment of the levels of vital blood parameters in donors is essential to evaluate their health status, ensure their suitability for donation, preserve the integrity of the circulatory system, and facilitate comprehensive health monitoring. The aim of our study was to analyse the levels of haemoglobin, haematocrit, erythrocyte count, MCV, MCH, and MCHC in 12 groups of first-time donors and experienced donors of both sexes at the John Paul II Regional Blood Donation and Treatment Centre in Slupsk, northern Poland. The donors were divided into three age groups (18-30 years, 31-45 years, and 46-65 years). METHODS: Using MANOVA multivariate significance tests, we examined the main effects of donor-related factors (age, sex, donor stage) on morphological blood parameters to evaluate different haematological parameters, such as Hb, Ht, RBC, MCV, MCH, and MCHC, and identified statistically significant relationships between all variables. RESULTS: The multivariate analysis of these three main factors showed that the variation in haemoglobin (Hb) levels accounted for 46% of the explained dependence in this statistical model. In particular, approximately half of the variability in the multivariate statistical analysis was attributed to the role of Hb and haematocrit (Ht). In addition, the ß-coefficient values for Hb and Ht were statistically higher in relation to donor sex and donor type (single versus repeat). These ß-coefficient values from our data represent the strength and direction of the relationship between the haematological parameters (Hb and Ht) and the specific donor characteristics. A higher ß-coefficient indicates a stronger influence of donor sex and donor type on these parameters, suggesting that these factors contribute significantly to the variation in the Hb and Ht levels. Based on our results, the comprehensive analysis of the entire statistical model of metabolic biomarkers revealed the following hierarchy: Hb > Ht > MCHC > MCV > RBC > MCH. The results obtained showed strong statistical relationships, as indicated by the high values of the key statistical indicators in our analysis. The coefficient of determination (R²) showed that the model explained a significant proportion of the variance in the data, while the F-test statistic confirmed the significance of the predictors. CONCLUSION: These strong statistical dependencies provided a clear justification for selecting this model over others, as it effectively represented the underlying relationships within the data. These statistics help to assess how well the model matches the actual data, thereby helping to reduce the risks associated with blood donation, optimise donor safety, and maintain the quality and efficiency of blood transfusion services.

NMDA Receptors and Indices of Energy Metabolism in Erythrocytes: Missing Link to the Assessment of Efficiency of Oxygen Transport in Hepatic Encephalopathy.

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that develops in patients with severe liver dysfunction and/or portocaval shunting. Despite more than a century of research into the relationship between liver damage and development of encephalopathy, pathogenetic mechanisms of hepatic encephalopathy have not yet been fully elucidated. It is generally recognized, however, that the main trigger of neurologic complications in hepatic encephalopathy is the neurotoxin ammonia/ammonium, concentration of which in the blood increases to toxic levels (hyperammonemia), when detoxification function of the liver is impaired. Freely penetrating into brain cells and affecting NMDA-receptor-mediated signaling, ammonia triggers a pathological cascade leading to the sharp inhibition of aerobic glucose metabolism, oxidative stress, brain hypoperfusion, nerve cell damage, and formation of neurological deficits. Brain hypoperfusion, in turn, could be due to the impaired oxygen transport function of erythrocytes, because of the disturbed energy metabolism that occurs in the membranes and inside erythrocytes and controls affinity of hemoglobin for oxygen, which determines the degree of oxygenation of blood and tissues. In our recent study, this causal relationship was confirmed and novel ammonium-induced pro-oxidant effect mediated by excessive activation of NMDA receptors leading to impaired oxygen transport function of erythrocytes was revealed. For a more complete evaluation of "erythrocytic" factors that diminish brain oxygenation and lead to encephalopathy, in this study, activity of the enzymes and concentration of metabolites of glycolysis and Rapoport-Lubering shunt, as well as morphological characteristics of erythrocytes from the rats with acute hyperammoniemia were determined. To elucidate the role of NMDA receptors in the above processes, MK-801, a non-competitive receptor antagonist, was used. Based on the obtained results it can be concluded that it is necessary to consider ammonium-induced morphofunctional disorders of erythrocytes and hemoglobinemia which can occur as a result of alterations in highly integrated networks of metabolic pathways may act as an additional systemic "erythrocytic" pathogenetic factor to prevent the onset and progression of cerebral hypoperfusion in hepatic encephalopathy accompanied by hyperammonemia.

Influence of Anticholinesterase Drugs on Activity and Properties of Na+,K+-ATPase in Rat Erythrocytes under Stress Caused by Intense Physical Exercise.

We studied the effect of intramuscular injection of physostigmine and neostigmine on Na+,K+-ATPase activity in erythrocytes of rats subjected to intense physical exercise. Both anticholinesterase drugs had a significant effect on the development of the stress response, which was expressed in a decrease in the manifestation of its individual components such as the concentration of ascorbic acid in the adrenal glands, stress-related erythrocyte polycythemia, and LPO indicators. Anticholinesterase drugs reverse the stress-induced decrease in Na+,K+-ATPase activity, as well as changes in its magnesium-dependent properties. There were no changes in the activity of the studied enzyme in the erythrocyte ghosts. We associate the observed differences with the correction of the functions of the cholinergic components of the hypothalamic-pituitary-adrenal axis leading to the development of a hypoergic type stress reaction.

Apicoplast-derived isoprenoids are essential for biosynthesis of GPI protein anchors, and consequently for egress and invasion in Plasmodium falciparum.

Glycophosphatidylinositol (GPI) anchors are the predominant glycoconjugate in Plasmodium parasites, enabling modified proteins to associate with biological membranes. GPI biosynthesis commences with donation of a mannose residue held by dolichol-phosphate at the endoplasmic reticulum membrane. In Plasmodium dolichols are derived from isoprenoid precursors synthesised in the Plasmodium apicoplast, a relict plastid organelle of prokaryotic origin. We found that treatment of Plasmodium parasites with apicoplast inhibitors decreases the synthesis of isoprenoid and GPI intermediates resulting in GPI-anchored proteins becoming untethered from their normal membrane association. Even when other isoprenoids were chemically rescued, GPI depletion led to an arrest in schizont stage parasites, which had defects in segmentation and egress. In those daughter parasites (merozoites) that did form, proteins that would normally be GPI-anchored were mislocalised, and when these merozoites were artificially released they were able to attach to but not invade new red blood cells. Our data provides further evidence for the importance of GPI biosynthesis during the asexual cycle of P. falciparum, and indicates that GPI biosynthesis, and by extension egress and invasion, is dependent on isoprenoids synthesised in the apicoplast.

Understanding the significance of oxygen tension on the biology of Plasmodium falciparum blood stages: From the human body to the laboratory.

Plasmodium falciparum undergoes sequestration within deep tissues of the human body, spanning multiple organ systems with differing oxygen (O2) concentrations. The parasite is exposed to an even greater range of O2 concentrations as it transitions from the human to the mosquito host, suggesting a high level of plasticity as it navigates these different environments. In this review, we explore factors that may contribute to the parasite's response to different environmental O2 concentrations, recognizing that there are likely multiple pieces to this puzzle. We first review O2-sensing mechanisms, which exist in other apicomplexans such as Toxoplasma gondii and consider whether similar systems could exist in Plasmodium. Next, we review morphological and functional changes in P. falciparum's mitochondrion during the asexual-to-sexual stage transition and discuss how these changes overlap with the parasite's access to O2. We then delve into reactive oxygen species (ROS) as ROS production is influenced by O2 availability and oxidative stress impacts Plasmodium intraerythrocytic development. Lastly, given that the primary role of the red blood cell (RBC) is to deliver O2 throughout the body, we discuss how changes in the oxygenation status of hemoglobin, the RBC's O2-carrying protein and key nutrient for Plasmodium, could also potentially impact the parasite's growth during intraerythrocytic development. This review also highlights studies that have investigated P. falciparum biology under varying O2 concentrations and covers technical aspects related to P. falciparum cultivation in the lab, focusing on sources of technical variation that could alter the amount of dissolved O2 encountered by cells during in vitro experiments. Lastly, we discuss how culture systems can better replicate in vivo heterogeneity with respect to O2 gradients, propose ideas for further research in this area, and consider translational implications related to O2 and malaria.

Data-driven discovery of potent small molecule ice recrystallisation inhibitors.

Controlling the formation and growth of ice is essential to successfully cryopreserve cells, tissues and biologics. Current efforts to identify materials capable of modulating ice growth are guided by iterative changes and human intuition, with a major focus on proteins and polymers. With limited data, the discovery pipeline is constrained by a poor understanding of the mechanisms and the underlying structure-activity relationships. In this work, this barrier is overcome by constructing machine learning models capable of predicting the ice recrystallisation inhibition activity of small molecules. We generate a new dataset via experimental measurements of ice growth, then harness predictive models combining state-of-the-art descriptors with domain-specific features derived from molecular simulations. The models accurately identify potent small molecule ice recrystallisation inhibitors within a commercial compound library. Identified hits can also mitigate cellular damage during transient warming events in cryopreserved red blood cells, demonstrating how data-driven approaches can be used to discover innovative cryoprotectants and enable next-generation cryopreservation solutions for the cold chain.

A Case of Erythrocyte Condensation Caused by Mycoplasma Pneumoniae Infection.

BACKGROUND: Blood routine testing was the most commonly used laboratory method in clinical practice. The results are often influenced by factors such as instruments, reagents, and samples, among which, the interference of cold agglutinin is a very rare element. In our article, we reported a case of red blood cell agglutination caused by Mycoplasma pneumoniae infection. METHODS: The number of blood cells were detected by blood routine analyzer with or without treatment at 37℃ water bath. The red blood cell agglutination was observed through blood smear staining. The cold agglutination test were performed using O-type red blood cells added into patient's plasma and refrigerated overnight at 4℃. We also used luminescent immunoassay technology to detect the content of MP antibodies in patient's serum. RESULTS: The patient's results were RBC (2.69 x 1012/L), MCH (48.5 pg), MCHC (522 g/L). Through a microscope, we observed red blood cell agglutination. The concentration of MP-igM was 60.37 AU/mL. The cold agglutination test was positive. Following a 37℃ water bath, the patient's results changed: RBC (3.85 x 1012/L), MCH (31.2 pg), MCHC (352 g/L). The phenomenon of massive agglutination of red blood cells has also disappeared. CONCLUSIONS: The cold agglutinin produced by MP infection can alter the results of red blood cell. During the epidemic period of MP infection, it is important to pay attention to the phenomenon of abnormal elevation of MCHC in clinical practice.

Red blood cell metabolomics identify ergothioneine as a key metabolite in DMARD-naïve rheumatoid arthritis and response to methotrexate.

Using a new red blood cell (RBC) metabolite extraction protocol, we performed a metabolomic analysis on RBCs in rheumatoid arthritis (RA) patients treated or not with methotrexate (MTX), with the two following objectives: to compare the RBC metabolic profiles of MTX-naïve RA patients and healthy controls (HC), and to investigate whether RBC profiles before and after MTX treatment in RA differed between responders and non-responders. Plasma analysis was performed in parallel. Metabolites were extracted and identified in RBCs and plasma by liquid chromatography-mass spectrometry. We compared the metabolomic fingerprints of 31 DMARD-naïve RA patients and 39 HCs. We also compared the RBC and plasma metabolomes of 25 RA patients who responded or not to MTX therapy before (M0) and after a 3-month treatment period (M3). Significance was determined by Storey's false discovery rate (FDR) q-values to correct for multiple testing. RA patients and HCs differed in the metabolomic signature of RBCs. The signature mainly contained amino acids (AA). Eleven metabolites, including 4 metabolites belonging to the carbohydrate subclass and 2 amino acids (creatine and valine) showed accumulation in RBCs from RA patients. Conversely, citrulline (fold change = 0.83; q = 0.025), histidine (fold change = 0.86; q = 0.014) and ergothioneine (EGT) (fold change = 0.66; q = 0.024), were lower in RBC of RA patients. Five plasma metabolites, including succinic acid and hydroxyproline, were higher in RA patients, and 7 metabolites, including DHEA sulfate, alanine, threonine and ornithine, were lower. Among RA patients undergoing MTX treatment pre-treatment (M0), EGT values were significantly lower in non-responders. In conclusion, low RBC levels of EGT, a food-derived AA barely detectable in plasma, characterize DMARD naïve RA patients and lack of response to MTX treatment.

Maternal Docosahexaenoic Acid Supplementation Alters Maternal and Fetal Docosahexaenoic Acid Status and Placenta Phospholipids in Pregnancies Complicated by High Body Mass Index.

INTRODUCTION: An optimal fetal supply of docosahexaenoic acid (DHA) is critical for normal brain development. The relationship between maternal DHA intake and DHA delivery to the fetus is complex and is dependent on placental handling of DHA. Little data exist on placental DHA levels in pregnancies supplemented with the recommended dose of 200 mg/d. Our objective was to determine how prenatal DHA at the recommended 200 mg/d impacts maternal, placental, and fetal DHA status in both normal-weight and high-BMI women compared to women taking no supplements. METHODS: Maternal blood, placenta, and cord blood were collected from 30 healthy pregnant women (BMI 18.9-43.26 kg/m2) giving birth at term. Red blood cells (RBCs) and villous tissue were isolated, and lipids were extracted to determine DHA content by LC-MS/MS. Data were analyzed by supplement group (0 vs. 200 mg/d) and maternal BMI (normal weight or high BMI) using two-way ANOVA. We measured maternal choline levels in maternal and cord plasma samples. RESULTS: Supplementation with 200 mg/d DHA significantly increased (p < 0.05) maternal and cord RBC DHA content only in pregnancies complicated by high BMI. We did not find any impact of choline levels on maternal or cord RBC phospholipids. There were no significant differences in total placental DHA content by supplementation or maternal BMI (p > 0.05). Placental levels of phosphatidylinositol (PI) and phosphatidic acid containing DHA species were higher (p < 0.05) in high-BMI women without DHA supplementation compared to both normal-BMI and high-BMI women taking DHA supplements. CONCLUSION: Maternal DHA supplementation at recommended doses cord increased RBC DHA content only in pregnancies complicated by higher BMI. Surprisingly, we found that obesity was related to an increase in placental PI and phosphatidic acid species, which was ameliorated by DHA supplementation. Phosphatidic acid activates placental mTOR, which regulates amino acid transport and may explain previous findings of the impact of DHA on placental function. Current recommendations for DHA supplementation may not be achieving the goal of improving fetal DHA levels in normal-weight women.

A systems serology approach to identifying key antibody correlates of protection from cerebral malaria in Malawian children.

BACKGROUND: Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) proteins are expressed on the surface of infected erythrocytes, mediating parasite sequestration in the vasculature. PfEMP1 is a major target of protective antibodies, but the features of the antibody response are poorly defined. METHODS: In Malawian children with cerebral or uncomplicated malaria, we characterized the antibody response to 39 recombinant PfEMP1 Duffy binding like (DBL) domains or cysteine-rich interdomain regions (CIDRs) in detail, including measures of antibody classes, subclasses, and engagement with Fcγ receptors and complement. Using elastic net regularized logistic regression, we identified a combination of seven antibody targets and Fc features that best distinguished between children with cerebral and uncomplicated malaria. To confirm the role of the selected targets and Fc features, we measured antibody-dependent neutrophil and THP-1 cell phagocytosis of intercellular adhesion molecule-1 (ICAM-1) and endothelial protein C (EPCR) co-binding infected erythrocytes. RESULTS: The selected features distinguished between children with cerebral and uncomplicated malaria with 87% accuracy (median, 80-96% interquartile range) and included antibody to well-characterized DBLß3 domains and a less well-characterized CIDRγ12 domain. The abilities of antibodies to engage C1q and FcγRIIIb, rather than levels of IgG, correlated with protection. In line with a role of FcγRIIIb binding antibodies to DBLß3 domains, antibody-dependent neutrophil phagocytosis of ICAM-1 and EPCR co-binding IE was higher in uncomplicated malaria (15% median, 8-38% interquartile range) compared to cerebral malaria (7%, 30-15%, p < 0.001). CONCLUSIONS: Antibodies associated with protection from cerebral malaria target a subset of PfEMP1 domains. The Fc features of protective antibody response include engagement of FcγRIIIb and C1q, and ability to induce antibody-dependent neutrophil phagocytosis of infected erythrocytes. Identifying the targets and Fc features of protective immunity could facilitate the development of PfEMP1-based therapeutics for cerebral malaria.

Antimicrobial spectrum against wound pathogens and cytotoxicity of star-arranged poly-l-lysine-based antimicrobial peptide polymers.

Introduction. As growing numbers of patients are at higher risk of infection, novel topical broad-spectrum antimicrobials are urgently required for wound infection management. Robust pre-clinical studies should support the development of such novel antimicrobials.Gap statement. To date, evidence of robust investigation of the cytotoxicity and antimicrobial spectrum of activity of antimicrobial peptides (AMP)s is lacking in published literature. Using a more clinical lens, we address this gap in experimental approach, building on our experience with poly-l-lysine (PLL)-based AMP polymers.Aim. To evaluate the in vitro bactericidal activity and cytotoxicity of a PLL-based 16-armed star AMP polymer, designated 16-PLL10, as a novel candidate antimicrobial.Methods. Antimicrobial susceptibilities of clinical isolates and reference strains of ESKAPE (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) pathogens, to 16-PLL10 were investigated. Human erythrocyte haemolysis and keratinocyte viability assays were used to assess toxicity. Modifications were made to 16-PLL10 and re-evaluated for improvement.Results. Minimum bactericidal concentration of 16-PLL10 ranged from 1.25 µM to ≥25 µM. At 2.5 µM, 16-PLL10 was broadly bactericidal against ESKAPE strains/wound isolates. Log-reduction in colony forming units (c.f.u.) per millilitre after 1 h, ranged from 0.3 (E. cloacae) to 5.6 (K. pneumoniae). At bactericidal concentrations, 16-PLL10 was toxic to human keratinocyte and erythrocytes. Conjugates of 16-PLL10, Trifluoroacetylated (TFA)-16-PLL10, and Poly-ethylene glycol (PEG)ylated 16-PLL10, synthesised to address toxicity, only moderately reduced cytotoxicity and haemolysis.Conclusions. Due to poor selectivity indices, further development of 16-PLL10 is unlikely warranted. However, considering the unmet need for novel topical antimicrobials, the ease of AMP polymer synthesises/modification is attractive. To support more rational development, prioritising clinically relevant pathogens and human cells, to establish selective toxicity profiles in vitro, is critical. Further characterisation and discovery utilising artificial intelligence and computational screening approaches can accelerate future AMP nanomaterial development.

Genetically influenced tobacco and alcohol use behaviors impact erythroid trait variation.

Genome wide association studies (GWAS) have associated thousands of loci with quantitative human blood trait variation. Loci and related genes that impact blood trait variation may regulate blood cell-intrinsic biological processes, or alternatively impact blood cell development and function via systemic factors. Clinical observations have linked tobacco or alcohol use with altered blood traits, but these trait relationships have not been systematically explored at the genetic level. Applying a Mendelian randomization (MR) framework to GWAS summary statistics, we explore relationships between smoking and drinking behaviors with 15 quantitative blood traits. We find that the effects of smoking and drinking are confined to red blood cell traits. An instrumental variable (IV) comprised of 113 single nucleotide polymorphisms (SNPs) associated with smoking initiation is associated with decreased hemoglobin (HGB: Effect = -0.07 standard deviation units [95% confidence interval = -0.03 to -0.10 SD units], P = 1x10-4), hematocrit (HCT: Effect = -0.06 [-0.03 - -0.09] SD units, P = 4x10-4), and red blood cell count (RBC: Effect = -0.05 [-0.02 - -0.09] SD units, P = 5x10-3) without impacting platelet count (P = 0.9) or white blood cell count (P = 0.6). Similarly, an IV associated with an increased number of alcoholic drinks consumed per week is associated with decreased HGB (Effect = -0.22 [-0.42 - -0.02] SD units, P = 3x10-2) and RBC (Effect = -0.27 [-0.51 - -0.03] SD units, P = 3x10-2). Using multivariable MR and causal mediation analyses, we find that an increased genetic predisposition to smoking initiation is associated with increased alcohol intake, and that alcohol use mediates the genetic effect of smoking initiation on red blood cell traits. These findings demonstrate a novel role for genetically influenced behaviors on human blood traits, revealing opportunities to dissect related pathways and mechanisms that influence hematopoiesis and blood cell biology.

Bovine lactoferrin inhibits Plasmodium berghei growth by binding to heme.

Bovine lactoferrin (bLF) is a 77 kDa glycoprotein that is abundant in bovine breast milk and exerts various bioactive functions, including antibacterial and antiviral functions. Few studies have explored bLF activity against parasites. We found that bLF affects hemozoin synthesis by binding to heme, inhibiting heme iron polymerization necessary for Plasmodium berghei ANKA survival in infected erythrocytes, and also binds to hemozoin, causing it to disassemble. In a challenge test, bLF administration inhibited the growth of murine malaria parasites compared to untreated group growth. To determine whether the iron content of bLF affects the inhibition of malaria growth, we tested bLFs containing different amounts of iron (apo-bLF, native-bLF, and holo-bLF), but found no significant difference in their effects. This indicated that the active sites were located within the bLFs themselves. Further studies showed that the C-lobe domain of bLF can inhibit hemozoin formation and the growth of P. berghei ANKA. Evaluation of pepsin degradation products of the C-lobe identified a 47-amino-acid section, C-1, as the smallest effective region that could inhibit hemozoin formation. This study highlights bLF's potential as a novel therapeutic agent against malaria, underscoring the importance of its non-iron-dependent bioactive sites in combating parasite growth.

Assessment of sub-lethal effects of Celcron on Java barb through erythrocyte morphology and acetylcholinesterase activity: Implications for environmental health in aquatic ecosystems.

Industrialization and the extensive use of chemicals have raised significant concerns about their environmental impacts, particularly on aquatic ecosystems. This study evaluated the sub-lethal effects of Celcron (Cec), an organophosphate insecticide, on the Java barb (Barbonymus gonionotus) through erythrocyte morphology and acetylcholinesterase (AChE) activity, aiming to refine biomarkers for environmental health assessments. We hypothesized that sub-lethal Cec exposure would induce significant erythrocyte abnormalities and decrease AChE activity in Java barb, with variable recovery rates between gill and kidney tissues. To test this, we exposed the juvenile Java barbs to two sub-lethal Cec concentrations - 0.01 ppm (10 % of the LC50) and 0.05 ppm (50 % of the LC50) -for 60 days. After the exposure period, the fish were placed in pesticide-free water to allow for recovery. Results indicated a significant decline in AChE activity in both liver and kidney tissues, with activity levels showing gradual recovery over time. Erythrocyte abnormalities, including nuclear and cellular changes, were significantly elevated in response to Cec exposure. The frequency of nuclear abnormalities such as micronuclei and binucleation increased in a concentration- and duration-dependent manner, with the gill blood exhibiting higher sensitivity and slower recovery compared to kidney blood. Cellular abnormalities such as twin, teardrop and spindle-shaped cells were also more prevalent in Cec-treated fish. Recovery from these abnormalities was observed but varied between gill and kidney blood, with gill blood showing higher sensitivity and slower recovery compared to kidney blood. This study underscores the utility of AChE activity and erythrocyte abnormalities as biomarkers for assessing pesticide impacts on aquatic organisms. The findings highlight the sensitivity of fish erythrocytes to environmental contaminants and emphasize the need for continued research to better understand the long-term effects of pesticide exposure on aquatic health and ecosystem stability.

Probing erythrocytes as sensitive and reliable sensors of metabolic disturbances in the crosstalk between childhood obesity and insulin resistance: findings from an observational study, in vivo challenge tests, and ex vivo incubation assays.

BACKGROUND: Although insulin resistance (IR) is among the most frequent and pathogenically relevant complications accompanying childhood obesity, its role in modulating and exacerbating obesity pathophysiology has not yet been completely clarified. METHODS: To get deeper insights into the interplay between childhood obesity and IR, we leveraged a comprehensive experimental design based on a combination of observational data, in vivo challenge tests (i.e., oral glucose tolerance test), and ex vivo assays (i.e., incubation of erythrocytes with insulin) using a population comprising children with obesity and IR, children with obesity without IR, and healthy controls, from whom plasma and erythrocyte samples were collected for subsequent metabolomics analysis. RESULTS: Children with concomitant IR showed exacerbated metabolic disturbances in the crosstalk between endogenous, microbial, and environmental determinants, including failures in energy homeostasis, amino acid metabolism, oxidative stress, synthesis of steroid hormones and bile acids, membrane lipid composition, as well as differences in exposome-related metabolites associated with diet, exposure to endocrine disruptors, and gut microbiota. Furthermore, challenge tests and ex vivo assays revealed a deleterious impact of IR on individuals' metabolic flexibility, as reflected in blunted capacity to regulate homeostasis in response to hyperinsulinemia, at both systemic and erythroid levels. CONCLUSIONS: Thus, we have demonstrated for the first time that metabolite alterations in erythrocytes represent reliable and sensitive biomarkers to disentangle the metabolic complexity of IR and childhood obesity. This study emphasizes the crucial need of addressing inter-individual variability factors, such as the presence of comorbidities, to obtain a more accurate understanding of obesity-related molecular mechanisms.

Gene-metabolite linkage marks stored red blood cell quality.

Red blood cell (RBC) transfusion has long been the cornerstone of treatment for multiple diseases, but there is a knowledge gap between biological and genetic factors impacting RBC storage quality and transfusion efficacy. In this issue of Cell Metabolism, Nemkov et al. present a multiomics approach to identify gene-metabolite associations in fresh and stored RBCs. These findings provide potential strategies to mark the quality of stored RBCs and improve their storage and transfusion performance.

The Influence of Environmental Conditions and Coinfection by Blood-Feeding Parasites on Red Blood Cell Physiology of an Ectothermic Host.

AbstractVector-borne blood parasites cause myriad sublethal effects and can even be deadly to endotherms, but far less is known about their impacts on ectothermic hosts. Moreover, the pathologies documented in endotherms are generally linked to infection by blood parasites rather than by their vectors. Here, we measured hematocrit, hemoglobin, and relative proportions of immature red blood cells to evaluate the physiological effects of two blood-feeding parasites and coinfection on ectothermic hosts, differentiating among pathological responses, extrinsic factors, and natural variations. We investigated a population of wild eastern hellbender salamanders (Cryptobranchus alleganiensis), which harbor leeches (Placobdella appalachiensis) that transmit blood parasites (Trypanosoma spp.) to their hosts, often resulting in coinfection. We observed seasonal changes in host hematology corresponding to water temperature and demonstrated their ability to modulate hematological parameters in response to acute stress. We reveal seasonal relationships between parasite dynamics and host physiology, in which peak parasitemia occurred when hosts had seasonally high hematocrit and hemoglobin concentrations. We found that coinfected individuals expressed symptoms of anemia, including a regenerative response to depletion of their red blood cells. We also documented a more pronounced pathological response to leech vectors than to the trypanosomes they transmit. Our research underscores the complex interactions between host physiology, multiple parasites, and environmental factors and highlights the pathologies associated with the vector in coinfections. Given the contributions of climate change and disease in the rapid global decline of ectotherms such as amphibians, our study provides timely foundational insights into multiple factors that influence their red blood cell physiology.

Giant membrane rings/loops in the cytosol of P. falciparum-infected erythrocytes and their relation to the parasite.

Striking morphological transformations characterize the invasion of a red blood cell by the malaria parasite. Shortly after the infection, parasite-induced membranes appear in the cytosol of the affected host erythrocyte. One intensely investigated membrane type, commonly called Maurer's clefts, has a slit-like morphology and can be arranged in the form of extended three-dimensional membrane stacks or networks. Here we report the three-dimensional reconstruction of a second membrane type, giant or extended membrane rings/loops, that have only occasionally been described on single ultrathin sections, however that have never been systematically examined so far. Serial ultrathin sectioning of P. falciparum-infected red blood cells, subsequent three-dimensional reconstructions, and in addition examination of Giemsa-stained blood films revealed that intraerythrocytic membrane rings/loops are not isolated structures but are locally in contact with the parasite. They consist either of the parasitophorous vacuolar membrane alone or contain the parasitophorous vacuolar membrane including the plasma membrane of the parasite and small amounts of parasite cytoplasm. We demonstrate that membrane rings/loops represent surface extensions of the parasite that maybe involved in ring stage parasite formation and Maurer's cleft generation at least in a subset of infected red blood cells.