Toxoplasma gondii adhesion and apoptosis of chicken erythrocytes

Toxoplasma gondi is thought to infect all nucleated cells in warm-blooded animals,including poultry,mammals,and humans.However,it is unclear whether T.gondi can infect chicken erythrocytes due to the nucleated nature of these cells.Due to the special role of chicken erythrocytes in innate immunity,we investigated the cell-cell interaction between T.gondi and erythrocytes to elucidate the role of chicken erythrocytes in T.gondi infection.Cellular apoptosis was analyzed by transwell assay and flow cytometry.An immunofluorescence method was used to examine the reorganization of vimentin during T.gondi infection in both Vero cells and chicken erythrocytes.The reorganization of actin was evaluated to further examine the invasion capacity of tachyzoites on chicken erythrocytes during infection.We discovered that T.gondi can adhere to but not invade chicken erythrocytes and eventually cause apoptosis in chicken erythrocytes.When tachyzoites were cocultured with chicken erythrocytes in vitro,the transcrip-tional levels of T.gondi MIC3,ROP16,and ROP18 were significantly decreased.In addition,the rearrangement of host cell vimentin,a type Il cytoskeleton protein regulated by T.gondii infection,was not observed.Similarly,the parasite-induced ring-shaped actin structure was not formed in the host-parasite junction.T.gondi(RH strain)tachyzoites pref-erentially invaded Vero cells and replicated in chicken blood monocytes,but they were not found in chicken erythro-cytes.These findings showed that although T.gondi could attach to the surface of chicken erythrocytes,but couldn't invade successfully.Interestingly,we found that the T.gondii secretome,lysates,and intact tachyzoites could cause apoptosis of chicken erythrocytes,which suggested a complex mechanism involved in the apoptosis of chicken erythrocytes induced by T.gondi.This study elucidated that T.gondi could not infect nucleated chicken erythrocytes and enriched our understanding of the transmission mechanism of T.gondii among avian species.

Effects of L.F04,the Active Fraction of Lycopus lucidus, on Erythrocytes Rheological Property

Objective: To study the effects of L.F04, the active fraction of Lycopus lucidus, on erythrocytes rheological property so as to investigate its mechanism in promoting blood circulation and removing blood stasis. Method: The effects of L.F04 (used for treatment for 10 days in different dosages) on deformability, aggregation and membrane liquidity of erythrocytes (MLE) as well as whole blood apparent viscosity (η_b) were examined on the basis of rat model of blood-stasis syndrome induced by venous injection of high molecular weight dextran. Result: As compared with the normal control group, the model group's RBC deformability and MLE were lower, and the aggregation of erythrocytes and η_b were higher. Compared with the model group, both L.F04 0.612g/kg and 0.306g/kg showed significant effect in improving deformability and inhibiting aggregation of red blood cells (RBC) and reducing blood viscosity. The trend of improving MLE was also shown. Conclusion: L.F04 could significantly improve the abnormal rheological property of erythrocytes.

Effects of Methanolic and Aqueous Extracts of Griffonia simplicifolia (Fabaceae) on the Inhibition of Falciformation of Human Hb SS Erythrocytes

Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transportation of red blood cells (RBCs) in blood vessels, leading to various clinical complications. Sickle cell disease is a widespread genetic disease in Black Africa. The objective of this study was to evaluate the sickling inhibition activity of Griffonia simplicifolia. Quantitative and qualitative tests were used to determine the major groups of secondary metabolites present in the Griffonia simplicifolia leaves extracts and the modified Emmel test was used to perform the study of sickling inhibition activity. The OECD 423 toxicity study showed that at a single dose of 2000 mg/kg bw, Griffonia simplicifolia leaves extracts are not toxic. All tested substances inhibit erythrocyte falciformation in a dose-dependent manner. The percentages of inhibition were 50.35%, 73% and 94.23% for aqueous extract, hydromethanolic extract and phenylalanine respectively at the concentration of 15 mg/mL. The methanolic extract (70%) had higher activity compared to the aqueous extract. These results suggest that the Griffonia simplicifolia extracts have some potential to be used as alternative antisickling therapy in SCD management.

20S proteasome and glyoxalase 1 activities decrease in erythrocytes derived from Alzheimer’s disease patients

As a result of accumulating methylglyoxal and advanced glycation end products in the brains of patients with Alzheimer’s disease,it is considered a protein precipitation disease.The ubiquitin proteasome system is one of the most important mechanisms for cells to degrade proteins,and thus is very important for maintaining normal physiological function of the nervous system.This study recruited 48 individuals with Alzheimer’s disease(20 males and 28 females aged 75±6 years)and 50 healthy volunteers(21 males and 29 females aged 72±7 years)from the Affiliated Hospital of Youjiang Medical University for Nationalities(Baise,China)between 2014 and 2017.Plasma levels of malondialdehyde and H2O2 were measured by colorimetry,while glyoxalase 1 activity was detected by spectrophotometry.In addition,20S proteasome activity in erythrocytes was measured with a fluorescent substrate method.Ubiquitin and glyoxalase 1 protein expression in erythrocyte membranes was detected by western blot assay.The results demonstrated that compared with the control group,patients with Alzheimer’s disease exhibited increased plasma malondialdehyde and H2O2 levels,and decreased glyoxalase 1 activity;however,expression level of glyoxalase 1 protein remained unchanged.Moreover,activity of the 20S proteasome was decreased and expression of ubiquitin protein was increased in erythrocytes.These findings indicate that proteasomal and glyoxalase activities may be involved in the occurrence of Alzheimer’s disease,and erythrocytes may be a suitable tissue for Alzheimer’s disease studies.This study was approved by the Ethics Committee of Youjiang Medical University for Nationalities(approval No.YJ12017013)on May 3,2017.

The Protective Effect of Propofol on Erythrocytes during Cardiopulmonary Bypass

To evaluate the relationship between erythrocyte injury and intracellular calcium ion overload, and the protective effect of propofol on erythrocytes during cardiopulmonary bypass (CPB), 40 children with congenital heart diseases who underwent surgical repair under CPB were studied. The patients were randomly divided into two groups: control group (group C) and propofol group (group P). Anesthesia was maintained in the patients in group P with 6 mg·kg -1 ·h -1 propofol, and those in the group C inhaled 1 %-2 % isoflurane. The blood samples were taken before CPB, at the 30th min of CPB, at the end of CPB, and 2 h and 24 h after CPB to measure the content of erythrocyte intracellular calcium ion (E Ca 2+ ), Ca 2+ Mg 2+ ATPase and Na + K + ATPase activities, index filtration of erythrocytes (IF), mean corpuscular volume (MCV) and the concentration of plasma free hemoglobin (F HB). Results showed that in the control group, E Ca 2+ , IF, MCV and F Hb were gradually increased and Ca 2+ Mg 2+ ATPase and Na + K + ATPase activities were decreased. The increase of E Ca 2+ was linearly paralleled to IF, MCV and F Hb. In propofol group, all the above mentioned parameters were significantly improved ( P <0.05). This study suggests that erythrocyte injury is related to elevation of intracellular calcium during CPB and propofol has a protective effect on erythrocyte injury.

The structure of the nucleosome core particle of chromatin in chicken erythrocytes visualized by using atomicforce microscopy

The structure of the nuclosome core particle of chromatin in chicken erythrocytes has been examined by usingAFM. The 146 hp of DNA wrapped twice around the corehistone octamer are clearly visualized. Both the ends ofentry/exit of linker DNA are also demonstrated. The dimension of the nucleosome core particles is- 1-4 um inheight and ～13-22 um in width. In addition, superbeads(width of - 48-57 urn, beight of-2-3 nm) are occasionallyrevealed, two turns of DNA around the core particles arealso detected.

Identification of potential oxidative stress biomarkers for spinal cord injury in erythrocytes using mass spectrometry

Oxidative stress is a hallmark of secondary injury associated with spinal cord injury.Identifying stable and specific oxidative biomarkers is of important significance for studying spinal cord injury-associated secondary injury.Mature erythrocytes do not contain nuclei and mitochondria and cannot be transcribed and translated.Therefore, mature erythrocytes are highly sensitive to oxidative stress and may become a valuable biomarker.In the present study, we revealed the proteome dynamics of protein expression in erythrocytes of beagle dogs in the acute and subacute phases of spinal cord injury using mass spectrometry-based approaches.We found 26 proteins that were differentially expressed in the acute(0–3 days) and subacute(7–21 days) phases of spinal cord injury.Bioinformatics analysis revealed that these differentially expressed proteins were involved in glutathione metabolism, lipid metabolism, and pentose phosphate and other oxidative stress pathways.Western blot assays validated the differential expression of glutathione synthetase, transaldolase, and myeloperoxidase.This result was consistent with mass spectrometry results, suggesting that erythrocytes can be used as a novel sample source of biological markers of oxidative stress in spinal cord injury.Glutathione synthetase, transaldolase, and myeloperoxidase sourced from erythrocytes are potential biomarkers of oxidative stress after spinal cord injury.This study was approved by the Experimental Animal Centre of Ningxia Medical University, China(approval No.2017-073) on February 13, 2017.

Relationship between glutathione and malonaldehyde levels in erythrocytes and the deformation index of erythrocyte in patients at various periods following acute cerebral infarction

BACKGROUND： Glutathione, as an in vivo free radical scavenger, plays an important role in the anti-oxidation defense mechanism in patients with acute cerebral infarction. OBJECTIVE： To observe the relationship between the levels of glutathione （GSH） and malonaldehyde （MDA）, the metabolite of lipid peroxidation, in erythrocyte and deformation index of erythrocyte in patients at various periods following acute cerebral infarction. DESIGN： Controlled observation.SETTING： Qilu Hospital of Shandong University and Institute of Cerebrovascular Disease of Qingdao Medical College. PARTICIPANTS： We chose 98 inpatients with acute cerebral infarction from Department of Neurology, Qilu Hospital of Shandong University from January to December 2000 , serving as cerebral infarction group, including 50 male and 48 female, with mean age of （62±7）years. There were 23 cases found on the 1^st day after onset; 25 cases on the 3^rd day after onset; 25 cases on the 7^th day after onset; 25 cases on the 14th days after onset, and they were all confirmed by craniocerebral CT or MRI. Another 30 homeochronous inpatients with neurosis, cervical syndrome, lumbar intervertebral disc herniation and motor neuron disease were chosen as control group, including 20 male and 10 female, with mean age of （52±8）years . There was no significant difference in age and gender distribution between two groups （P 〉 0.05）. Patients in the two groups were informed of detected index.METHODS：①Ulnar venous blood was chosen from the patients who were fasted on the 1^st, 3^rd,7^th and 14^th days after onset. Deformation index of erythrocyte was measured with BL88-CKX laser diffraction erythrocyte deformeter and photographing was performed. GSH level in erythrocyte was measured with DTNB assay introduced by Beu-tler. MDA level in erythrocyte was measured with modified thiobarbituric acid colorimetric method.②At each sample collecting , according to the criteria accepted by the Fourth National Conference of Cerebrovascular Disease, intergrant of neurologic impairment 〈 15 points was regarded as mild （n=46）, 15 to 30 points as moderate （n=40）and, 〉 30 points as severe （n=12）. ③ t test was used to compare data between two groups , and linear correlation analysis was used in relationship analysis among indexes. MAIN OUTCOME MEASURES ：① Comparison of erythrocyte GSH and MDA levels and deformation index of erythrocyte at various periods between patients with acute cerebral infarction and controls. ②Correlation of erythrocyte GSH level with erythrocyte MDA level and with deformation index of erythrocyte in patients with cerebral infarction . ③ Relationship between erythrocyte GSH level and severity of disease in patients with acute cerebral infarction. RESULTS： Totally 98 patients with acute cerebral infarction and 30 controls all entered the stage of result analysis. ① Erythrocyte GSH level and deformation index of erythrocyte were lower on the 1^st, 3^rd, 7^th and 14^th days after onset in cerebral infarction group than in control group （P 〈 0.05-0.01）, and erythrocyte MDA level was significantly higher in cerebral infarction group than in control group （P 〈 0.05-0.01）. The three indexes changed most significantly on day 3 after onset in patients, and began to recover or decrease on day 7 after onset and inclined to be normal on day 14 after onset. ② Erythrocyte GSH level was significantly negatively correlated with erythrocyte MDA level in patients with acute cerebral infarction on the 1^st, 3^rd, 7^th and 14^th days after onset （r=-0.534, -0.713, -0.645, -0.656, respectively, P 〈 0.05-0.01 ） ,and significantly positively correlated with erythrocyte deformation index （t-=0.502, 0.560, 0.455, 0.504, respectively, P 〈 0.05）. ③Erythrocyte GSH level was significantly lower in moderate or severe patients with acute cerebral infarction than in mild patients[（0.215±0.088）,（0.192±0.102）, （0.281±0.090） g/L, P〈 0.05]. CONCLUSION：①Erythrocyte GSH and MDA levels and deformation index of erythrocyte change significantly on the 3^rd day following acute cerebral infarction. Index detection results gradually tended to be normal on from the 7^th day to 14^th days day after onset. ② Change of erythrocyte GSH level can reflect the severity of disease of patients with acute cerebral infarction.③Decrease of erythrocyte GSH level in patients with acute cerebral infarction is one of reasons that result in the decrease of deformation ability of erythrocyte.

Dielectric properties of nucleated erythrocytes as simulated by the double spherical-shell model

The dielectric properties of nucleated erythrocytes from bullfrogs were measured in a frequency range of 10 kHz–110 MHz.The complex permittivity(ε*),complex conductivity(κ*),and complex resistivity(ρ*)were analyzed and compared in the 10.63%to 37.58%haematocrit(Hct)range.The relaxation behavior,the passive electrical properties,and the cellular structure parameters,including the cell membrane,the cytoplasm,the nuclear membrane,and the nucleoplasm of the nucleated erythrocyte suspensions were investigated.The method used is based on the binomial Cole–Cole equation and the double spherical-shell physical models.Upon the elimination of the electrode polarization effect,two definite relaxations related to the interfacial polarization are observed on low-and high-frequency dispersions.The permittivity values and the characteristic frequency values differ by one order of magnitude:the low-frequency relaxation increments[?ε1=(5.63±1.43)×103]and the characteristic frequency[fc1=(297.06±14.48)kHz]derived from the cell membrane,the high-frequency relaxation increments[?ε2=(5.21±1.20)×102]and the characteristic frequency[fc2=(3.73±0.06)MHz]derived from the dielectric response to the external electric field of the nuclear membrane,respectively.Moreover,the other core dielectric parameters,such as the relative permittivity of the cell membrane[εm=(7.57±0.38)]and the nuclear envelope[εne=(23.59±4.39)],the conductivity of the cytoplasm(hemoglobin,κHb=(0.50±0.13)S/m]and the nuclear endoplasm[κnp=(2.56±0.75)S/m],and the capacitance of the bilayer membranes[Cm:(0.84±0.04)μF/cm2],and Cne:(0.52±0.10)μF/cm2]were also accurately and reliably measured.This work presents a feasible method to evaluate the dielectric parameters and the cellular structure of the erythrocytes of bullfrogs.Moreover,it paves the way for new studies on the haematology of frogs and the detection of nucleated cells via dielectric impedance spectroscopy.

Observation on the specific binding site of p195 protein on human erythrocytes using colloidal gold labelling

Objective: p195, the major protein on the surface of Plasmodium falciparum merozoites, has been found to have ability to bind sialic acid residues on the surface of human erythrocytes, and this binding is thought to be a prerequisite for recognition of human erythrocyte by merozoite- This study attempted to map out the binding site of p195, thus providing a theoretical clue to developing an antimalaria vaccine which blockades invasion of merozoites into human erythrocytes. Methods: Eight proteins derived from pl95 were expressed in E. coli, and purified by Ni-chelate affinity chromatography. The re folded proteins were labelled with colloidal gold. The labelled protein complexes were co-incubated with human erythrocytes separately and simultaneously, and the proteins were put into the culture supernatant of P- falciParum to observe their effect on invasion of merozoites into erythrocytes. Results: A fragment of p195, M6 (amino acid sequence: 384 - 595), was found to have the ability to bind human erythrocytes. M6 gold complexes showed no ability to bind erythrocytes treated with trypsin or neuraminidase. M6 was also found to have the ability to inhibit invasion of merozoites of P. falciparym into human erythrocytes. Conclusiou: A fragment of p195, M6, has the ability to bind human erythrocytes. The binding is dependent on sialic acid residues, and may be a prerequisite to recognition of erythrocytes by merozoites.

Effect of Repetitive Bleeding on NADH-Cytochrome b_5 Methemoglobin Reductase Activity and Molybdenum Content in Erythrocytes of Rats

Reticulocytosls in rats was induced by repetitive bleeding. Both the in vitro and the in vivo studies showed that the detected reductive speed of methemoglobin of the bleeding group was faster than that of the control group at all time intervals. At the same time, the NADH-cytochrome b5 methemoglobin reductase activity and the molybdenum content in erythrocytes of the bleeding group were significantly increased. Regressional analysis showed that there was a significantly positive correlation between the enzyme activity and the molybdenum content. It is proposed that molybdenum might be required for the enzyme activity

AGING OF HUMAN MATURE ERYTHROCYTES IS LIKE A PROCESS OF APOPTOSIS IN ENUCLEATED CELL

Apoptosis of nucleated cells is well known, but how about the unnucleated cells is still not elucidated. In the present paper, the morphological and biochemical features of the aged erythrocytes were observed and compared with the characteristic events of apoptosis. Membrane of aged erythrocytes tends to shrink, protrude, from vesicle and lose lipid asymmetry. Aged erythrocytes were removed by phagocytosis. Both of the events are very similar to the apoptotic nucleated cells. The authors suggested that aging of erythro- cytes is also a process of apoptosis.

Biomarkers of oxidative stress in erythrocytes as a function of human age

Despite more than 300 theories to explain the aging process, oxidative stress theory offers the best mechanism to explain aging and age related disorders. Several studies has shown the importance of oxidative stress during aging. Pub Med, Science Direct and Springer online data bases are taken into consideration to write this mini-review. Human erythrocytes are most abundant and specialized cells in the body. Erythrocytes were extensively studied due to their metabolism and gas transport functions. Recent studies on erythrocytes have provided us detailed information of cell membrane and its structural organization that may help in studying the aging and age associated changes. The susceptibility of an organism is associated with the antioxidant potential of the body. Erythrocytes have potent antioxidant protection consisting of enzymatic and nonenzymatic pathways that counteract with reactive oxygen species, thus maintaining the redox regulation in the body. The non-enzymatic and enzymatic antioxidants and other biomarkers associated with erythrocyte membrane transport functions are the main content of this review. Biomarkers of oxidative stress in erythrocytes and its membrane were taken into the consideration during human aging that will be the main subject of this minireview.

Anomeric specificity of D-glucose metabolism study in rat and human erythrocytes

The anomeric specificity of D-glucose metabolism in erythrocytes has been since 1985 the matter of extensive investigations reported in about ten publications. The present report aims at providing an integrated review of the major findings on this issue.

Crossover from Weak to Strong Nonlinear Disorder in the Viscoelasticity of Glucose Incubated Erythrocytes

Biomechanics is a wide interdisciplinary field, which includes all mechanical aspects from living organisms. As traditional erythrocytes viscoelastic analysis is mostly qualitative, the development of new quantitative methods capable of analyzing at the same time biological and mechanical aspects of the cells in flow, when changing from healthy controls to glucose incubated at different concentrations, is crucial for restricting the subjectivity in the study of the cell behaviour. On the other hand, it is important to appreciate the role of mathematics in the analysis of tissues and cells. Recent developed non linear mathematical methods are particularly fruitful when they are strongly correlated with cells sensitivity to initial conditions. An optic system called Erythrodeformeter has been developed and constructed in our laboratory, in order to evaluate the erythrocytes viscoelastic properties. To analyze the erythrocytes viscoelastic dynamics we used the technique of Time Delay Coordinates suggested by Takens, False Nearest Neighbours proposed by Abarbanel and co-workers, and the forecasting procedure proposed by Sugihara and May, the so called Correlation Coefficient. The results suggest that through this random walk analysis, apparent noise associated with deterministic chaos can be used not only to distinguish but also to characterize at the same time biological and mechanical aspects of the cells in flow, when changing from healthy controls to glucose incubated at different concentrations.

Effect of static magnetic field on erythrocytes characterizations

The interaction of static magnetic field (SMF) with living organisms is a rapidly growing field of investigation. Recently, exposure to moderate intensity SMFs (1 mT – 1 T) has attracted much attention for its various medical applications. This study was designed to show the microscopic effect of SMF on erythrocytes in vitro. For this purpose SMF system was constructed in my lab on basis of the idea of cell tracking velocimetry system. The changes in erythrocytes surface area, sphericity, and adhesion number for erythrocytes were calculated to quantify the effect of SMF on erythrocytes characterizations. The results showed that SMF increased erythrocytes surface area and reduced their sphericity. The adhesion number of erythrocytes under the influence of SMF showed the tendency of erythrocytes to adhere with each other. These findings indicate that more study on microscopic scales must be carried out in order to investigate the effect of SMF on erythrocytes.

Oxidative Stress and Oxidative Damage in Male Rat Erythrocytes Associated with Prolonged Exposure to Smoke Pollution

Exposure of animals to different duration of smoke can result in a wide range of adverse clinical conditions. Toxicological consequences arising from prolonged exposure may not be totally enumerated. The present study was to evaluate the oxidative stress-inducing potential of a short and long-time exposure of male rat erythrocytes to environmentally relevant to public health. Male Wistar rats were exposed to open municipal land-fill smoke for 30 and/or 60 days. The oxidative stress in erythrocytes was evaluated by assessing the magnitude of malondialdehyde production and reduced glutathione (GSH) contents and the activities of superoxide dismutase (SOD), catalase (C) and glutathione reductase (GR) after 30 and/or 60 days of exposure. After 30 days there was no change in SOD, catalase and GR activities and no alterations in GSH and lipid peroxidation (LPO). After 60 days, the levels and activities of SOD (23.62%), catalase (5.24%), GR (14.87%) decreased. Overall, the study demonstrates that the chronic exposure of male rats to smoke results in induction of oxidative stress and simultaneous reduction in antioxidative defense system in erythrocytes at 60 days of exposure.

The Fusability of Erythrocytes as a Method for Evaluating the Instability of Their Membranes

A novel approach to the study of erythrocytes instability based on assessment fusability of their plasma membrane is presented. The fusability of erythrocytes normal blood, stored for 7 days at 4°C, and type 2 patients with diabetes were studied. Human erythrocytes were fused by incubation with La3+ at final concentrations from 50 to 200 μM. Erythrocytes aggregates were incubated at 37°C for 120 min. The fusability of erythrocytes was evaluated using a light microscope. It was shown that La3+ induced extensive fusion of erythrocytes after 7 days of blood storage and erythrocytes of patients with diabetes. Incubation of normal erythrocytes at 37°C for 120 min does not induce cell fusion.

Assessment of the Elasticity of Erythrocytes in Different Physiological Fluids by Laser Traps

In the study of the mechanical properties of the erythrocytes (red blood cells-RBCs) the blood sample is commonly diluted in fluids that do not compromise the integrity of the cells. Fetal bovine serum (FBS), newborn bovine serum (NBBS), and phosphate buffer (PBS) solution with a concentration that can provide the right osmotic pressure are fluids commonly used to dilute the blood samples in such studies. Here we have presented the effect of these fluids on the elastic properties of the RBCs that we studied using laser traps. Two laser traps are directly used to trap and deform the cell by exerting a force distributed on the entire cell. The relative changes in size of the cell are studied as a function of the applied force to investigate any effects on the mechanical deformability of RBCs when the cells are suspended in these fluids. The results have shown that the elasticity of the RBCs in the NBBS is not statistically different from the elasticity of the cells in the PBS solution;however the results for the elasticity of the cells in FBS are found to be significantly higher.

Variations induced in human erythrocytes by ultra-low X-ray doses

In this work, the effect of different ultra-low doses of X-ray on human erythrocytes was investigated. Also, the effect of ascorbic acid added to erythrocyte suspension before X-rays was studied. The mean X-ray exposure level was about 10 μGy/h. Samples of erythrocytes suspension with and without ascorbic acid was exposed to X-ray doses in the range from 2.5 to 20 μGy. The obtained results showed pronounced radio-hemolysis of erythrocytes at doses starting from nearly 7.5 μGy. The effect was enhanced, for low doses, when ascorbic acid of relatively high concentration was added to erythrocyte samples. The changes may be attributed to a dose-dependent damage by oxidative stress at the level of the whole cell and to the production of reactive oxygen species, which can cause this damage. It may be concluded that X-rays, even at low levels of exposure, can induce oxidizing effect on erythrocytes. Accordingly, such results should be taken into account for workers operating on X-rays equipments.