Hemolytic Agent Research Articles

Toxicity and Potential Pharmacological Activities in the Persian Gulf Venomous Sea Anemone, Stichodactyla haddoni.

Numerous proteins and peptides in venomous marine animals are potentially active molecules with pharmacological properties. Particular condition of the Persian Gulf as a closed ecosystem is a good opportunity to study of biological activities and toxicity of venomous animals. In this study, Stichodactyla haddoni (S. haddoni), a sea anemone, selected to tracing for possible pharmaceutical agents and toxicological characterization. Analgesic, edematogenic, dermonecrotic, LD50, phospholipase, and proteolytic activities of the venom were estimated. LD50 was recorded at 675 μg by intraperitoneal injection. Analgesic activitiy of crude venom on Balb/c mice at both 100 and 150 µg were dose dependent as a linear trend. Three folds increase of activity was seen at both 100 and 150 µg after 240 min comparing to activity of morphine at 200 µg. The crude venom at amount of 0.23 µg produced 50% hemolysis. The highest edematogenic activity was seen on Balb/c mice just two hours after injection for both 168 µg (157%) and 335 µg (247%). The crude venom at 675 µg made 4 mm inflammation area on rabbit skin after 3 h but the amount of 1000 µg induced 8 mm necrosis area. Potent analgesic activity of the venom was seen below its toxic dose that was very greater than the other sea anemones in the other geographical areas. The results indicate that a persistent edematogenic activity could be happened after envenomation. Instant potent edematogenic and rapid dermonecrotic activity were significant phenomena. HD50 at 0.23 µg indicates that a very potent hemolytic agent exists in the venom. The results would also be of high value to better management of envenomation. This study confirmed the great value of further studies on the Persian Gulf S. haddoni venom.

Photo-induced antibacterial activity of a porphyrin derivative isolated from the harmful dinoflagellate Heterocapsa circularisquama

The dinoflagellate Heterocapsa circularisquama is highly toxic to bivalves. However, significant toxicity to finfish species has not been reported. We previously found that H. circularisquama has light-dependent haemolytic agents. Purification and chemical structural analyses revealed that the haemolytic agent H2-a is a porphyrin derivative, which exhibits light-dependent cytotoxicity toward tumour cells. To clarify the biological activity of H2-a further, its antibacterial activities against Gram-positive and Gram-negative bacteria were investigated in this study. A fraction (F5) equivalent to H2-a purified from the methanol extract of H. circularisquama showed potent light-dependent bactericidal activity toward Staphylococcus aureus, and the activity was concentration- and light illumination time-dependent; however, Escherichia coli was highly resistant to F5. Electron microscopic observation suggested that F5 induces morphological changes in S. aureus in a light-dependent manner. Further analysis using other bacterial species showed that the Gram-positive bacterium Bacillus subtilis was more sensitive than the Gram-negative bacteria Pseudomonas aeruginosa and Vibrio alginolyticus. These results indicate that F5 is a photo-induced antibacterial agent with relatively higher specificity to Gram-positive bacteria. Iodometric assay suggested that singlet oxygen was generated from light-illuminated F5. Histidine, a specific singlet oxygen scavenger, markedly inhibited the photosensitising antibacterial activity of F5 against S. aureus, suggesting the involvement of singlet oxygen in antibacterial activity. The antibacterial spectrum of F5 was evidently different from that of 5,10,15,20-tetra (N,N,N-trimethylanilinium) porphyrin tetratosylate, a commercially available porphyrin compound with antibacterial activity. Our results demonstrate that H. circularisquama has a novel antibacterial photosensitiser, a porphyrin derivative, with relatively higher specificity to Gram-positive bacteria. To the best of our knowledge, this is the first study to discover a porphyrin derivative with antibacterial activity in marine microalga.

Melatonin diminishes oxidative stress in plasma, retains erythrocyte resistance and restores white blood cell count after low dose lipopolysaccharide exposure in mice.

The aim of the study was to elucidate the effects of melatonin administration (10 mg/kg, 10 days) in a model of inflammation and oxidative stress induced by low-dose bacterial lipopolysaccharide (LPS, once 150 μg). Assays were carried out in quadruplicate in the control, melatonin (10 mg/kg, 10 days), acute LPS administration (once 150 μg) and LPS plus melatonin groups. Blood morphological examination was performed. Erythrocyte resistance to haemolytic agents, ceruloplasmin, diene conjugates, malondialdehyde, oxidatively modified protein concentrations, total antioxidant capacity and antioxidant enzyme activity in plasma were measured. LPS administration in mice resulted in white blood cell (WBC) depletion, erythrocyte cell membrane impairment and oxidative stress in plasma characterised by lipid and protein oxidative processes, decreased antioxidative defence and augmented ceruloplasmin concentrations. Melatonin treatment provided to LPS-exposed animals restored WBC counts, ameliorated erythrocyte membrane damage and decreased overall oxidative stress in plasma. Melatonin provides multilevel protection in animals exposed to low-dose LPS.

Novel fluconazole derivatives with promising antifungal activity

The fungistatic nature and toxicity concern associated with the azole drugs currently on the market have resulted in an increased demand for new azole antifungal agents for which these problematic characteristics do not exist. The extensive use of azoles has resulted in fungal strains capable of resisting the action of these drugs. Herein, we report the synthesis and antifungal activity of novel fluconazole (FLC) analogues with alkyl-, aryl-, cycloalkyl-, and dialkyl-amino substituents. We evaluated their antifungal activity by MIC determination and time-kill assay as well as their safety profile by hemolytic activity against murine erythrocytes as well as cytotoxicity against mammalian cells. The best compounds from our study exhibited broad-spectrum activity against most of the fungal strains tested, with excellent MIC values against a number of clinical isolates. The most promising compounds were found to be less hemolytic than the least hemolytic FDA-approved azole antifungal agent voriconazole (VOR). Finally, we demonstrated that the synthetic alkyl-amino FLC analogues displayed chain-dependent fungal membrane disruption as well as inhibition of ergosterol biosynthesis as possible mechanisms of action.

Haemolytic activity and reactive oxygen species production of four harmful algal bloom species

Based on haemolytic activity and reactive oxygen species (ROS) production of Chattonella marina, Chattonella antiqua, Heterocapsa circularisquama, Alexandrium tamiyavanichii and Karenia mikimotoi, the species were categorized into four types. (1) H. circularisquama: haemolytic activity was detected in both cell suspension and cell-free culture supernatant, but with greater activity in cell suspension than in the supernatant suggesting the presence of both cell surface and secreted haemolytic agents. (2) A. tamiyavanichii: equal haemolytic activities were detected in both the cell suspension and cell-free culture supernatant suggesting the presence of only secreted haemolytic agents. (3) K. mikimotoi: haemolytic activity was detected only in the cell suspension, indicating haemolytic agents occur only on the cell surface. (4) C. marina and C. antiqua: no significant haemolytic activity was detected in either cell suspension or cell-free culture supernatant, but high ROS were detected in the cell suspensions. Heterocapsa circularisquama and K. mikimotoi showed lethal effects on rotifers (Brachionus plicatilis), whereas A. tamiyavanichii, C. marina and C. antiqua had no effect. Our results suggest that H. circularisquama, K. mikimotoi and A. tamiyavanichii produce haemolytic agents with distinct characteristics, whereas C. marina and C. antiqua have an extremely potent ability to produce ROS.

Intracellular haemolytic agents of Heterocapsa circularisquama exhibit toxic effects on H. circularisquama cells themselves and suppress both cell-mediated haemolytic activity and toxicity to rotifers (Brachionus plicatilis)

A harmful dinoflagellate, Heterocapsa circularisquama, is highly toxic to shellfish and the zooplankton rotifer Brachionus plicatilis. A previous study found that H. circularisquama has both light-dependent and -independent haemolytic agents, which might be responsible for its toxicity. Detailed analysis of the haemolytic activity of H. circularisquama suggested that light-independent haemolytic activity was mediated mainly through intact cells, whereas light-dependent haemolytic activity was mediated by intracellular agents which can be discharged from ruptured cells. Because H. circularisquama showed similar toxicity to rotifers regardless of the light conditions, and because ultrasonic ruptured H. circularisquama cells showed no significant toxicity to rotifers, it was suggested that live cell-mediated light-independent haemolytic activity is a major factor responsible for the observed toxicity to rotifers. Interestingly, the ultrasonic-ruptured cells of H. circularisquama suppressed their own lethal effect on the rotifers. Analysis of samples of the cell contents (supernatant) and cell fragments (precipitate) prepared from the ruptured H. circularisquama cells indicated that the cell contents contain inhibitors for the light-independent cell-mediated haemolytic activity, toxins affecting H. circularisquama cells themselves, as well as light-dependent haemolytic agents. Ethanol extract prepared from H. circularisquama, which is supposed to contain a porphyrin derivative that displays photosensitising haemolytic activity, showed potent toxicity to Chattonella marina, Chattonella antiqua, and Karenia mikimotoi, as well as to H. circularisquama at the concentration range at which no significant toxicity to rotifers was observed. Analysis on a column of Sephadex LH-20 revealed that light-dependent haemolytic activity and inhibitory activity on cell-mediated light-independent haemolytic activity existed in two separate fractions (f-2 and f-3), suggesting that both activities might be derived from common compounds. Our results suggest that the photosensitising haemolytic toxin discharged from ruptured H. circularisquama cells has a relatively broad spectrum of phytoplankton toxicity, and that physical collapse of H. circularisquama cells can lead not only to the disappearance of its own toxicity, but also to mitigation of the effects of other HABs.

A Survey of Practice and Knowledge of Refugee and Migrant Pregnant Mothers Surrounding Neonatal Jaundice on the Thailand-Myanmar Border.

Background: In populations with a high prevalence of glucose-6-phosphate dehydrogenase deficiency, practices that can induce haemolysis need to be identified to raise awareness of preventable risks. The aim of this survey was to determine the proportion of prospective mothers using haemolytic agents and their knowledge and practice surrounding neonatal jaundice.Methods: Pregnant mothers were invited to participate in a cross-sectional survey conducted at Shoklo Malaria Research Unit on the Thailand–Myanmar border.Results: From 12 April 2015 to 12 June 2015, 522 pregnant women completed the survey. Mothball use in the household was reported by 41.4% (216 of 522) of prospective mothers and menthol containing products on baby skin by 46.7% (244 of 522).Conclusion: Just over 40% of the households reported use of naphthalene-containing mothballs. Future health promotion activities that focus on reducing naphthalene mothball and menthol-containing products use have the potential to reduce rates of severe neonatal jaundice in this population.

Haematocrit, eggshell colouration and sexual signaling in the European starling (Sturnus vulgaris).

BackgroundOne hypothesis to explain the blue–green colour of the eggs of many bird species is that it is a sexually-selected signal of the laying female’s quality, which males use to determine their investment. This hypothesis requires that eggshell pigmentation carries a cost or is otherwise linked to female quality. One potential cost is that biliverdin, a haem derivative and the pigment responsible for eggshell colouration, is limiting. To assess this potential cost, we attempted to manipulate haematocrit and haemoglobin in free-living European starlings (Sturnus vulgaris Linnaeus). Upon collecting unmanipulated first clutches, we treated females with phenylhydrazine (PHZ), a haemolytic agent, and measured the blue–green chroma and reproductive performance of replacement clutches. We also investigated whether eggshell colour was associated with haematocrit or haemoglobin levels in unmanipulated first clutches. To test whether eggshell colour might act as a sexual signal, we examined associations between eggshell colour and reproductive performance, as well as the provisioning rate of the male.ResultsPHZ-treatment did not affect eggshell colour in replacement clutches. In unmanipulated first clutches, eggshell colour was not correlated with haematocrit or haemoglobin levels. Eggshell colour was correlated with female mass in unmanipulated first clutches but not replacement clutches. Chicks from eggs with higher eggshell colour had higher haemoglobin levels and longer tarsi just prior to fledging, suggesting that eggshell colour could reflect brood quality. However, eggshell colour was not correlated with the provisioning rate of the male or any other measure of reproductive performance.ConclusionsWe found no evidence to support the hypothesis that the availability of resources required for the synthesis of pigment limits eggshell colour in European starlings, or that eggshell colour is used by males to determine their level of reproductive investment. We found little evidence that eggshell colour is correlated with female or offspring quality in this species.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-016-0084-x) contains supplementary material, which is available to authorized users.

Polycythemia and high levels of erythropoietin in blood and brain blunt the hypercapnic ventilatory response in adult mice.

Changes in arterial Po2, Pco2, and pH are the strongest stimuli sensed by peripheral and central chemoreceptors to adjust ventilation to the metabolic demand. Erythropoietin (Epo), the main regulator of red blood cell production, increases the hypoxic ventilatory response, an effect attributed to the presence of Epo receptors in both carotid bodies and key brainstem structures involved in integration of peripheral inputs and control of breathing. However, it is not known whether Epo also has an effect on the hypercapnic chemoreflex. In a first attempt to answer this question, we tested the hypothesis that Epo alters the ventilatory response to increased CO2 levels. Basal ventilation and hypercapnic ventilatory response (HCVR) were recorded from control mice and from two transgenic mouse lines constitutively expressing high levels of human Epo in brain only (Tg21) or in brain and plasma (Tg6), the latter leading to polycythemia. To tease apart the potential effects of polycythemia and levels of plasma Epo in the HCVR, control animals were injected with an Epo analog (Aranesp), and Tg6 mice were treated with the hemolytic agent phenylhydrazine after splenectomy. Ventilatory parameters measured by plethysmography in conscious mice were consistent with data from electrophysiological recordings in anesthetized animals and revealed a blunted HCVR in Tg6 mice. Polycythemia alone and increased levels of plasma Epo blunt the HCVR. In addition, Tg21 mice with an augmented level of cerebral Epo also had a decreased HCVR. We discuss the potential implications of these findings in several physiopathological conditions.

Hospital Prevalence of Canine Hemolytic Anemia in Punjab

The present study was conducted on anemic dogs presented to the small animal clinics of the department of Veterinary Medicine GADVASU Ludhiana, Punjab from September 2014 to August 2015. Total number of the cases screened randomly in this period were 1749 and among them 214 cases were having haemolytic anemia and the prevalence was 12.25%. The most prevalent causes of haemolytic agent was Ehrlichia canis in this study followed by Babesia gibsoni, primary immune-mediated haemolytic anemia, neoplasia, Babesia canis and toxicity.

Advanced Encryption Standard Algorithm Applied Research in Medical Reagent Sales Management

Blood cell analyzer to complete cell detection function to fit the diluent, the hemolytic agent, sheath fluid reagent for medical use. In order to guarantee the stability of testing results, as well as protecting the interests of enterprise sales of reagents, under normal circumstances, instruments and reagents password authentication is needed in order to work properly. Reagent sales typically use encryption methods to achieve the instrument specifies the use of reagents, but unable to control reagent for sales by region. Using a symmetric key encryption algorithm Advanced Encryption Standard, and put forward a new reagent encryption method. The method can realize the enterprise to the reagent according to regional sales purposes, and can be used to control the designated on the instrument for custom reagent. The verification and analysis of the encryption method using VC platform.

The water channel aquaporin-1a1 facilitates movement of CO₂ and ammonia in zebrafish (Danio rerio) larvae.

The present study tested the hypothesis that zebrafish (Danio rerio) aquaporin-1a1 (AQP1a1) serves as a multi-functional channel for the transfer of the small gaseous molecules, CO2 and ammonia, as well as water, across biological membranes. Zebrafish embryos were microinjected with a translation-blocking morpholino oligonucleotide targeted to AQP1a1. Knockdown of AQP1a1 significantly reduced rates of CO2 and ammonia excretion, as well as water fluxes, in larvae at 4 days post fertilization (dpf). Because AQP1a1 is expressed both in ionocytes present on the body surface and in red blood cells, the haemolytic agent phenylhydrazine was used to distinguish between the contributions of AQP1a1 to gas transfer in these two locations. Phenylhydrazine treatment had no effect on AQP1a1-linked excretion of CO2 or ammonia, providing evidence that AQP1a1 localized to the yolk sac epithelium, rather than red blood cell AQP1a1, is the major site of CO2 and ammonia movements. The possibility that AQP1a1 and the rhesus glycoprotein Rhcg1, which also serves as a dual CO2 and ammonia channel, act in concert to facilitate CO2 and ammonia excretion was explored. Although knockdown of each protein did not affect the abundance of mRNA and protein of the other protein under control conditions, impairment of ammonia excretion by chronic exposure to high external ammonia triggered a significant increase in the abundance of AQP1a1 mRNA and protein in 4 dpf larvae experiencing Rhcg1 knockdown. Collectively, these results suggest that AQP1a1 in zebrafish larvae facilitates the movement of CO2 and ammonia, as well as water, in a physiologically relevant fashion.

HPLC fractionation and pharmacological assessment of green tea seed saponins for antimicrobial, anti-angiogenic and hemolytic activities

Herbal medicinal products have proven to be safe, economical and effective alternatives to synthetic chemical pharmaceuticals. The green tea plant (Camellia sinensis) is of profound medicinal value due to the presence of potent bioactive constituents. The purpose of the present work is to investigate saponins from green tea seeds for potential use as anti-angiogenic, antimicrobial, and hemolytic agents. Green tea seed saponins were separated into six fractions by reverse phase HPLC. The presence of three aglycone chains in the saponins of each fraction was confirmed by acid hydrolysis. Anti-angiogenic activity was evaluated using saponin fractions at concentrations in the range of 2.5 ~ 25 μg/mL. Antimicrobial activity was evaluated by thin-layer chromatography (TLC) using E. coli; S. mutans, a zoonotic Salmonella species and the fungal strain, A. niger. Saponin fractions were more potent against E. coli (gram negative bacteria) than against S. mutans (gram positive bacteria) and strongly inhibited six strains of zoonotic Salmonella. Green tea saponins also showed potent anti-angiogenic effects. All saponin fractions exhibited hemolytic activity. Our results confirm that green tea saponins have antimicrobial, anti-angiogenic, and hemolytic activities; indicating their potential as natural pharmaceutical products.

Interaction of poloxamine block copolymers with lipid membranes: Role of copolymer structure and membrane cholesterol content

Interactions of X-shaped poly(ethylene oxide)–poly(propylene oxide) (PEO–PPO) block copolymers with cell membranes were investigated recording the π-A isotherms of monolayer systems of dipalmitoylphosphatidylcholine (DPPC):cholesterol 100:0; 80:20 and 60:40 mol ratio and evaluating the capability of the copolymers to trigger haemolysis or to protect from haemolytic agents. Four varieties of poloxamine (Tetronic 904, 908, 1107 and 1307) were chosen in order to cover a wide range of EO and PO units contents and molecular weights, and compared to a variety of poloxamer (Pluronic P85). The π-A isotherms revealed that the greater the content in cholesterol, the stronger the interaction of the block copolymers with the lipids monolayer. The interactions were particularly relevant at low pressures and low lipid proportions, mimicking the conditions of damaged membranes. Relatively hydrophobic copolymers bearing short PEO blocks (e.g., T904 and P85) intercalated among the lipids expanding the surface area (ΔGexc) but not effectively sealing the pores. These varieties showed haemolytic behavior. Oppositely, highly hydrophilic copolymers bearing long PEO blocks (e.g., T908, T1107 and T1307) caused membrane contraction and outer leaflet sealing due to strong interactions of PEO with cholesterol and diamine core with phospholipids. These later varieties were not haemolytic and exerted a certain protective effect against spontaneous haemolysis for both intact erythrocytes and cholesterol-depleted erythrocytes.

Review lipopeptides biosurfactants: Mean classes and new insights for industrial, biomedical, and environmental applications.

Lipopeptides are microbial surface active compounds produced by a wide variety of bacteria, fungi, and yeast. They are characterized by high structural diversity and have the ability to decrease the surface and interfacial tension at the surface and interface, respectively. Surfactin, iturin, and fengycin of Bacillus subtilis are among the most popular lipopeptides. Lipopepetides can be applied in diverse domains as food and cosmetic industries for their emulsification/de-emulsification capacity, dispersing, foaming, moisturizing, and dispersing properties. Also, they are qualified as viscosity reducers, hydrocarbon solubilizing and mobilizing agents, and metal sequestering candidates for application in environment and bioremediation. Moreover, their ability to form pores and destabilize biological membrane permits their use as antimicrobial, hemolytic, antiviral, antitumor, and insecticide agents. Furthermore, lipopeptides can act at the surface and can modulate enzymes activity permitting the enhancement of the activity of certain enzymes ameliorating microbial process or the inhibition of certain other enzymes permitting their use as antifungal agents. This article will present a detailed classification of lipopeptides biosurfactant along with their producing strain and biological activities and will discuss their functional properties and related applications.

Compensatory erythropoiesis has no impact on the outcome of the in vivo Pig-a mutation assay in rats following treatment with the haemolytic agent 2-butoxyethanol.

The Pig-a assay has rapidly gained international interest as a useful tool for assessing the mutagenic potential of compounds in vivo. Although a large number of compounds, including both mutagens and non-mutagens, have been tested in the rat Pig-a assay in haematopoietic cells, there is limited understanding of how perturbations in haematopoiesis affect assay performance. Of particular concern is the possibility that regenerative haematopoiesis alone, without exposure to a genotoxic agent, could result in elevated Pig-a mutant cell frequencies. To address this concern, Wistar-Han rats were dosed by oral gavage with a non-genotoxic haemolytic agent, 2-butoxyethanol (2-BE). Dose levels ranging from 0 to 450 mg/kg were tested using both single administration and 28-day treatment regimens. Haematology parameters were assessed at minimum within the first 24h of treatment and 8 days after the final administration. Pig-a mutant frequencies were assessed on Days 15 and ~30 for both treatment protocols and also on Days 43 and 57 for the 28-day protocol. Even at doses of 2-BE that induced marked intravascular lysis and strong compensatory erythropoiesis, the average Pig-a mutant phenotype red blood cell and reticulocyte frequencies were within the historical vehicle control distribution. 2-BE therefore showed no evidence of in vivo mutagenicity in these studies. The data suggest that perturbations in haematopoiesis alone do not lead to an observation of increased mutant frequency in the Pig-a assay.

Reduced Protein Synthesis and p53 Activation in Late-Stage Erythroblasts Mediate the Erythroid Differentiation Defect in Mice with Ribosomal Protein S14 Haploinsufficiency

The 5q-syndrome is a subtype of myelodysplastic syndrome (MDS) with a defined clinical phenotype associated with heterozygous deletion of Chromosome 5q. The RPS14 gene was identified as a critical gene for the erythroid phenotype of the 5q- syndrome using an RNA interference screen. We generated a murine model for conditional, heterozygous inactivation of Rps14 in the bone marrow to investigate the biological basis of del(5q) MDS.To explore the role of Rps14 on hematopoietic stem cell (HSC) function and erythroid differentiation, we generated a mouse model in which Rps14 exons 2-4 are flanked by loxP sites. Following crosses to Mx1Cre transgenic mice, we induced Rps14 excision in hematopoietic cells by poly(I:C). Two weeks after induction of the gene excision, mice developed significantly reduced hemoglobin and red blood cell counts with a significantly higher MCV compared to Mx1Cre+ controls. Bone marrow analysis confirmed an erythroid differentiation defect specifically at the transition from the CD71+Ter119+ (RII, basophilic erythroblasts/early polychromatophilic erythroblasts) to the CD71intermediate/lowTer119+ (RIII/IV, poly/orthochromatophilic erythroblasts, enucleated erythrocytes) population, accompanied by significant up-regulation of p21 in the RIII population. Histopathology of spleens demonstrated compensatory extramedullar erythropoiesis. The bone marrow was normocellular with a significant increase in hypolobulated megakaryocytes correlating with high platelet counts and dysplastic platelets in the peripheral blood, reflecting the pathognomonic megakaryocyte phenotype in del(5q) MDS. At 50 weeks of age, Rps14-/+Mx1Cre+ developed a more severe macrocytic anemia in the peripheral blood.We thus tested whether a more severe erythroid phenotype could be induced by treatment with the hemolytic agent phenylhydrazine (PH; 2x single dose 25mg/kg body weight, s.c.). In response to PH treatment, Rps14 haploinsufficient mice developed a more severe anemia than control mice, had a delayed reticulocyte response, and a differentiation defect again specifically at the transition from RII to RIII/IV accompanied by a compensatory increase in the RI (CD71+Ter119-) pro-erythroblast/early basophilic population. Megakaryocyte-erythrocyte progenitors were increased, and pre-CFU-E and CFU-E numbers were normal. To further elucidate the mechanisms by which haploinsufficiency of Rps14 causes ineffective erythropoiesis, we analyzed cell cycle, p53 and apoptosis. We found a significant induction of p53 specifically in the RI population and a dramatic increase of apoptotic cells in RIII, suggesting that increased apoptosis accounts for the erythroid failure. We therefore tested if genetic inactivation of p53 rescues the erythroid phenotype. In Rps14-/+p53-/+Mx1Cre+ mice the erythroid differentiation defect was restored and mice had a comparable response to PH as Mx1Cre+ controls. In PH dose escalation experiments (35mg/kg), Rps14 haploinsufficient mice died from the severe anemia and delayed reticulocyte response, while compound p53 loss rescued the erythroid failure. Accordingly, forced erythroid differentiation in vitro was significantly impaired in Rps14 haploinsufficient hematopoietic stem and progenitor cells.We measured protein synthesis by O-propargyl (OP)-puromycin incorporation. Rps14 haploinsufficient cells had a significantly reduced protein synthesis in CD71low cells (late erythroblasts) that could not be fully restored by p53 inactivation although the protein synthesis in p53 heterozygote cells alone was significantly higher. The decreased protein synthesis in Rps14-/+p53-/-Mx1Cre+ compound cells might also account for the decreased stem cell expansion in repopulation assays compared to cells with only p53 loss.Our data provide in vivo evidence that Rps14 haploinsufficiency contributes to the erythroid differentiation defect in del(5q) MDS by reduced protein synthesis and p53 induction in late-stage erythroblasts. This murine model recapitulates the erythroid und megakaryocytic phenotype of the 5q-sydrome and provides a model for understanding the underlying mechanisms in the pathogenesis of ribosomal-mediated erythroid failure in del(5q) MDS. DisclosuresNo relevant conflicts of interest to declare.

Studies on the role of goat heart galectin-1 as an erythrocyte membrane perturbing agent

Galectins are β-galactoside binding lectins with a potential hemolytic role on erythrocyte membrane integrity and permeability. In the present study, goat heart galectin-1 (GHG-1) was purified and investigated for its hemolytic actions on erythrocyte membrane. When exposed to various saccharides, lactose and sucrose provided maximum protection against hemolysis, while glucose and galactose provided lesser protection against hemolysis. GHG-1 agglutinated erythrocytes were found to be significantly hemolyzed in comparison with unagglutinated erythrocytes. A concentration dependent rise in the hemolysis of trypsinized rabbit erythrocytes was observed in the presence of GHG-1. Similarly, a temperature dependent gradual increase in percent hemolysis was observed in GHG-1 agglutinated erythrocytes as compared to negligible hemolysis in unagglutinated cells. The hemolysis of GHG-1 treated erythrocytes showed a sharp rise with the increasing pH up to 7.5 which became constant till pH 9.5. The extent of erythrocyte hemolysis increased with the increase in the incubation period, with maximum hemolysis after 5h of incubation. The results of this study establish the ability of galectins as a potential hemolytic agent of erythrocyte membrane, which in turn opens an interesting avenue in the field of proteomics and glycobiology.

Amphiphilic macromolecules on cell membranes: from protective layers to controlled permeabilization.

Antimicrobial and cell-penetrating peptides have inspired developments of abiotic membrane-active polymers that can coat, penetrate, or break lipid bilayers in model systems. Application to cell cultures is more recent, but remarkable bioactivities are already reported. Synthetic polymer chains were tailored to achieve (i) high biocide efficiencies, and selectivity for bacteria (Gram-positive/Gram-negative or bacterial/mammalian membranes), (ii) stable and mild encapsulation of viable isolated cells to escape immune systems, (iii) pH-, temperature-, or light-triggered interaction with cells. This review illustrates these recent achievements highlighting the use of abiotic polymers, and compares the major structural determinants that control efficiency of polymers and peptides. Charge density, sp. of cationic and guanidinium side groups, and hydrophobicity (including polarity of stimuli-responsive moieties) guide the design of new copolymers for the handling of cell membranes. While polycationic chains are generally used as biocidal or hemolytic agents, anionic amphiphilic polymers, including Amphipols, are particularly prone to mild permeabilization and/or intracell delivery.

Gender Differences of Oxidative Stress Biomarkers and Erythrocyte Damage in Well-Trained Horses During Exercise

The aim of this study was to determine the effects of gender differences on the blood oxidative stress biomarkers, antioxidant defenses, and resistance of erythrocytes to hemolytic agents of trained horses before and after exercise. The study was carried out on nine mares and 14 stallions of Ukrainian Warmblood well-trained horses, involved in jumping, eventing, and dressage. Oxidative stress biomarkers, antioxidant defenses, and osmotic resistance of erythrocytes were assessed. Trained stallions showed a decrease in lipid peroxidation and higher glutathione reductase activity, whereas mares presented a higher superoxide dismutase activity after exercise. The resistance of erythrocytes was similar in female and male. No statistically significant differences were observed in the percentage of hemolyzed erythrocytes between after and before exercise. A correlation between the oxidative stress biomarkers and antioxidant defenses in the stallions after exercises were observed, which may indicate a protective response of superoxide dismutase and catalase against exercise-induced oxidative stress.