Camel Erythrocytes Research Articles

Genetic diversity of groEL and msp4 sequences of Anaplasma ovis infecting camels from Tunisia

To date, no information is available regarding the infection of camels (Camelus dromedarius) by Anaplasma ovis in North African region. Several animal species can be infected by A. ovis which further complicates its natural infection cycle. In this paper, we investigated the occurrence and the genetic diversity of A. ovis in camels and ticks collected from them in Tunisia and the risk factor analysis. Camel blood samples (n = 412) and tick (n = 300) samples, identified as Hyalomma dromedarii (n = 149, 49.6%), H. impeltatum (n = 142, 47.3%) and H. excavatum (n = 9, 3%), were analyzed by conventional PCR followed by the sequencing of msp4 and groEL genes. A. ovis DNA was identified in five camels (1.2%), but not in infesting ticks (0%). The microscopic examination revealed the specific infection of camel erythrocytes by Anaplasma inclusions. The msp4 and groEL typing confirmed the natural infection of camels by A. ovis and revealed two different msp4 genotypes earlier detected in Tunisian small ruminants and their infested ticks, and five different and novel groEL genetic variants forming a separately sub-cluster within A. ovis cluster. The occurrence of different A. ovis strains specific to camels associated with a low prevalence of this Anaplasma species in camels may enrich knowledge regarding the distribution and the transmission cycle of this bacterium in arid and Saharan areas of Tunisia.

Near-Newtonian Blood Behavior - Is It Good to Be a Camel?

From a certain level of exercise-intensity onward, hematocrit increases in horses, which brings more oxygen carriers into the bloodstream. Camels, however, when used in competitive racing could be even in need of iron supplementation and blood transfusions due to a severe reduction of their available hematocrit compared to their resting hematocrit. Since the extrinsic and intrinsic mechanical properties of camel erythrocytes (RBC) are so different compared to RBCs of other mammals, the question arises whether this observation might be a response to endurance exercise aiming at keeping the RBC count low. Rheometry indicated dromedary camel blood to behave almost Newtonian, which is unique amongst mammals. Shear thinning did increase with the hematocrit, but remained marginal compared to horses. As a result, camel whole blood viscosity (WBV) exceeded horse WBV at high shear rates, an effect, which was significantly augmented when the packed cell volume (PCV) was increased. Therefore, in camels any infusion of RBCs into the bloodstream can increase the cardiac work and the energy input into the endothelium more effectively, which should generate vascular remodeling in the long term. Yielding, however, was completely absent in camel blood, confirming low cohesion between its components at quasi-static flow. Camel blood remained a viscous liquid without a threshold even at unphysiologically high PCVs. This can help to washout lactate when camels start to dehydrate and might contribute to the sustained working ability of these animals. The subtle pseudoplastic behavior and the high viscosity contrast across the RBC membrane point to weak coupling between blood flow and red cell behavior. We predict that RBCs flow as separate entities and can show various types of motion, which can lead to friction instead of being collectively aligned to the flow direction. In comparison to horses, this behavior will become relevant at higher RBC counts in front of flow obstacles and possibly cause vascular remodeling if the PCV rises during strenuous exercise, a matter that should be avoided.

Characterization of an interesting selenium-dependent glutathione peroxidase (Se-GPx) protecting cells against environmental stress: The Camelus dromedarius erythrocytes Se-GPx

Camel lives most of its life under high environmental stress in the desert. Glutathione peroxidase plays a key role in protecting cells against oxidative stress. For the first time, selenium-dependent glutathione peroxidase (Se-GPx) was purified from camel erythrocytes, biochemically characterized, and some of its properties were studied. The enzyme was purified using ethanol-chloroform treatment, acetone precipitation and ion exchange chromatography. A purification fold of 33.72 with 0.19% yield were obtained. The native molecular weight of the enzyme was estimated to be about 69 kDa. On SDS-PAGE, the enzyme was composed of two different subunits with a molecular weight of approximately 53 and 21 kDa. An optimum temperature of 47 °C and an optimum pH of 7.2 were found. The activation energy was 41.71 kJ/mol. This enzyme was inhibited by thiol reagents, D,L-Dithiothreitol and β-Mercaptoethanol, and was sensitive to bivalent cations. The enzyme had a general specificity toward hydroperoxides, and high specificity for reduced glutathione. The purified enzyme contained 3.06 mol of selenium per mol of protein. The Km and Vmax values for hydrogen peroxide and reduced glutathione were 0.72 and 1.58 mM, and 25.33 and 31.03 U/mg, respectively. The biochemical properties of camel Se-GPx were different comparing to those of mammalian species. Lower molecular weight, heterodimeric structure, higher optimum temperature, relatively lower optimum pH, lower content of selenium and higher affinity for hydrogen peroxide at low reduced glutathione concentration, these could be explained by the fact that camel is able to live in the intense environmental stress in the desert.

Ultrastructure Morphology of Camel Blood Cells

The main purpose of this study was to provide a basic cytology of camel blood by electron microscopy.Camel blood was collected, prepared, identified from two adult of one-humped female camels were clinically healthy. The fine structure of the red cells in camels was investigated and certain characteristic features were noted.The Scanning electron micrograph of camel erythrocytes showing elliptical shape and tropical waist (Tw) non-nucleated with 7.0±0.5 µm in diameter. The transmission of electron microscopy of camel erythrocytes showed elliptical shape and tropical waist (Tw), also a trilaminar of membranes (Me) of marginal band that a zone of high electron density. The area of (Me) showed structures are dense and the (Me) was contacted with individual microtubules (Mt). There are few intracellular organelles were observed with the occasional exception of number of mitochondria (Mi). The camel erythrocyte is trilaminar, the inner and outer membranes are of high electron density between which is a zone of lesser electron density. There are few intracellular organelles were observed with the occasional exception of number of mitochondria. The erythrocyte marginal band consisting of microtubules was observed.The fine structure of the camel monocytes showed revealed the presence of a few short cisternae of rough endoplasmic reticulum and various forms of vesicles associated with the Golgi complex were seen near the mitochondria, which are located adjacent to the main indentation in the nuclei. Membrane bound granules of different sizes and spherical or oval in shape, were observed, vacuoles of various forms, a well-defined Golgi complex, few rough endoplasmic reticulum and mitochondria were noticed randomly distributed in the cytoplasm.

Effects of Vitamin E and Vitamin C on Hydrogen Peroxide-Induced Hemolysis in Moroccan Dromedary Camels (Camelus Dromedarius)

Antioxidant vitamins may affect an organism’s capacity for defense against damage caused by reactive oxygen species (ROS), and biological markers of the dietary exposure to these compounds is of importance. The present study was designed to evaluate the protective effect of vitamin E and vitamin C against the hemolysis induced by hydrogen peroxide (H 2O2) in camel’s red blood cells in vitro, and for assessing the vulnerability of camel erythrocytes to oxidative stress (OS). Vitamin E and vitamin C were able to protect the red blood cells against the H2O2-induced hemolysis and thiobarbituric acid reactive species (TBARS) formation. The antioxidative property of these vitamins in reducing oxidative injury showed in this work, may suggest that these molecules may be very helpful to fight the ROS during OS induced by transportation, heat, deshydratation, aging, and parasite, infectious and metabolic diseases in dromedary camels.

Osmotic and diffusive properties of intracellular water in camel erythrocytes: Effect of hemoglobin crowdedness

Camel erythrocytes have exceptional osmotic resistance and is believed to be due to augmented water-binding associated with the high hydrophilicity of camel hemoglobin. In practical terms this means that the proportion of osmotically non-removable water in camel erythrocytes is nearly 3-fold greater than that in human erythrocytes (approximately 65 vs approximately 20%). The relationship between water diffusion and the osmotic characteristics of intracellular water is the subject of this report. The amount of osmotically inactive water is 2-fold greater in camel hemoglobin solution in vitro compared to that of human, but water diffusion does not differ in camel and human hemoglobin solutions. However, the evaluation of water diffusion by magnetic resonance measurements in camel erythrocytes revealed approximately 15% lower apparent diffusion coefficient (ADC) compared with human erythrocytes. When human erythrocytes were dehydrated to the level of camel erythrocytes, their osmotic and water diffusion properties were similar. These results show that a lower ADC is associated with a more pronounced increase in osmotically inactive water fraction. It is proposed that increased hemoglobin hydrophilicity allows not only augmented water-binding, but also a closer hemoglobin packaging in vivo, which in turn is associated with slower ADC and increased osmotic resistance.

Lipid concentrations in erythrocyte membranes in normal, starved, dehyrated and rehydrated camels ( Camelus dromedarius), and in normal sheep ( Ovis aries) and goats ( Capra hircus)

The present work compared the effects of starvation (7 days) and dehydration (10 days) followed by rehydration, on erythrocyte membranes of the desert camel ( Camelus dromedarius). Total lipids, cholesterol, total phospholipids, phospholipid classes, fatty acids of phospholipid classes and proteins in the erythrocyte membranes of normal camels, sheep ( Ovis aries) and desert goats ( Capra hircus) have also been investigated. The results suggested that the lipid profile in the erythrocytes of the normal camels was significantly different from those found in normal sheep and goats. Between the two later species no significant differences were observed. In the erythrocyte membranes of the camel two classes of phospholipids (phosphatidylcholine and sphingomyelin), cholesterol and proteins were significantly higher than in sheep and goats. These constituents were not altered significantly by dehydration or starvation in the camel. These results may help to explain the resistance of camel erythrocytes to haemolysis after rehydration, infection with blood parasites or when confronted with other harsh environmental conditions.

Distribution of Total, Free, Peptide-bound and Protein-bound Hydroxyproline in the Erythrocytes from Different Species

We have investigated the presence of total, free, protein-bound and peptide-bound hydroxyproline (Hyp) in the erythrocytes of different mammals namely, camel, bovine, sheep, human, rabbit and rat. Sheep erythrocytes had the highest concentration of free Hyp, followed by camel, bovine, rat, human and rabbit. The concentration of peptide-bound Hyp was the highest in camel erythrocytes followed by bovine, sheep (p<0.01), rat, human and rabbit (p<0.001). However, human erythrocytes had the highest concentration of protein-bound Hyp followed by rat, bovine, camel, rabbit and sheep (p<0.05). Camel erythrocytes had the highest concentration of total Hyp followed by bovine, sheep, rat (p<0.01), human and rabbit (p<0.001). Results showed that the ratio of free to peptide-bound Hyp was significantly higher in sheep as compared to other examined species (p<0.001). These variations in Hyp distribution may result from differences in collagen structure and/or composition in these species. Alternatively, they may be due to the fact that the circulating concentration of free Hyp is controlled by liver Hyp oxidase which regulates the concentration of free Hyp in plasma.

A Comparative Study of Erythrocytic Total, Free, Short-chain Acyl and Long-chain Acyl Carnitine Concentrations in Arabian Camel (Camelus dromedarius) with Different Species

Carnitine plays a critical role in lipid metabolism. Carnitine deficiency may adversely affect the oxidation of fatty acids and further aggravate abnormal lipid metabolism. Its presence is considerable in tissues that utilise fatty acids as an important source of energy, such as the heart and skeletal muscle. The presence of total (TC), free (FC), short-chain acyl (SC) and long-chain acyl (LC) carnitine was shown for the first time in one-humped Arabian camel (Camelus dromedarius) erythrocytes. The results showed that concentrations of FC, AC, SC and TC in camel erythrocytes were significantly higher when compared with bovine, rabbit, rat and humans; however, these carnitine fractions were not significantly different when compared with sheep. Moreover, the concentration of LC in camel erythrocytes was significantly higher when compared with rabbit, rat and humans, but there was no significant difference compared with either sheep or bovine. The results showed that there were significant variations in the ratio of acyl carnitine (AC) to FC among the species erythrocytes studied. The ratio in camel erythrocytes was significantly higher when compared with rat, but there was no significant difference in this ratio in camel erythrocytes when compared with bovine, rabbit, sheep and humans. The higher carnitine concentrations and a higher proportion of AC in erythrocytes of the Arabian camel suggest an adaptive mechanism that could be common to desert animal species.

Prevalence, species differentiation, haemolytic activity, and antibiotic susceptibility of aeromonads in untreated well water.

The use of untreated water for drinking and other activities have been associated with intestinal and extraintestinal infections in humans due to Aeromonas species. In the present study aeromonads were isolated from 48.7% of 1,000 water samples obtained from wells and other miscellaneous sources. Aeromonas species were detected in 45% of samples tested in spring, 34.5% in summer, 48% in autumn and 60% of samples tested in winter. Speciation of 382 strains resulted in 225 (59%) being A. hydrophila, 103 (27%) A. caviae, 42 (11%) A. sobria and 11 (3%) atypical aeromonads. Of 171 Aeromonas strains tested for their haemolytic activity, 53%, 49%, 40% and 37% were positive in this assay using human, horse, sheep and camel erythrocytes respectively. The results obtained indicate that potentially enteropathogenic Aeromonas species are commonly present in untreated drinking water obtained from wells in Libya (this may also apply to other neighbouring countries) which may pose a health problem to users of such water supplies. In addition, ceftriaxone and ciprofloxacin are suitable drugs that can be used in the treatment of Aeromonas-associated infections, particularly in the immunocompromised, resulting from contact with untreated sources of water.

N-Ethylmaliemide (NEM)-stimulated Passive Potassium Transport in Camel Erythrocytes: Inhibitory Effects of Age, Furosemide, Sodium Fluoride and Okadaic Acid

The effects of age, and the inhibitory effects of furosemide, sodium fluoride, and okadaic acid on N-ethylmaliemide (NEM)-stimulated, ouabain-resistant potassium influx were investigated in camel erythrocytes. The NEM-stimulated influx which declined with the age of erythrocytes, was partially inhibited by 2mmol/L furosemide, 20mmol/L sodium fluoride, and completely inhibited by 150nm okadaic acid. The effect of all chemical inhibitors was significant if added before the NEM pretreatment.

Augmented Water Binding and Low Cellular Water Content in Erythrocytes of Camel and Camelids

We investigated a link between hemoglobin primary structure, hemoglobin hydrophobicity-hydrophilicity, and erythrocyte water content in various mammalian species. Some hemoglobin molecules, particularly those of the camel and camelids, contain more charged amino acid residues and are more hydrophilic than the hemoglobins of human and a number of other mammalian species. To test the in vivo significance of these alterations of hemoglobin primary structure, we determined the osmotically unresponsive erythrocyte water fractions in mannit solutions of various osmolarities at 4°C. Among the species investigated, the size of the osmotically unresponsive erythrocyte water fraction relates in a positive linear way to hemoglobin hydrophilicity. The extreme low total erythrocyte water content of camel erythrocytes (1.1–1.3 g water/g dry mass) may be explained by a comparatively high osmotically unresponsive erythrocyte water fraction. It is proposed that alterations of hemoglobin sequences of camel and camelids may be the part of a natural selection process aimed at protecting these animals against osmotic dehydration in arid environments.

N-ethylmaliemide (NEM)-stimulated potassium transport in camel erythrocytes

In this study N-ethylmaliemide (NME)-stimulated, ouabain-resistant potassium influx in camel erythrocytes was measured using the radioactive rubidium tracer 86Rb+. The results showed that camel erythrocytes responded to NEM pretreatment by a threefold increase in influx which was Cl- dependent. The anion dependence of K+ influx in pre-treated cells was Br- > Cl- > NO3-. The pH dependence curve for NEM-stimulated K+ influx and the combination between volume and NEM stimulation in camel erythrocytes were determined. The findings indicated that the camel erythrocytes potassium transport system has many similarities to that of other mammalian species.

Effect of malathion on kinetic parameters of acetylcholinesterase (EC 3.1.1.7) in vitro.

Kinetic analysis of the interaction of malathion with camel erythrocyte acetylcholinesterase was investigated in the present study. The Michaelis-Menten constant (K(m)) for the hydrolysis of acetylthiocholine iodide (ASCh) was found to be 53.15 microM and the Vmax was 0.287 mumol/min/mg protein. The Kmapp and Vmaxapp were both decreased by increased malathion concentration. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the pure uncompetitive type with Ki value estimated as 102.1 ppm. The Kiapp decreased while Vmaxiapp increased by an increased concentration in ASCh.

Heat-shock response in camel ( Camelus dromedarius) blood cells and adaptation to hyperthermia

1. 1. We demonstrate the difference between the reactions of camel ( Camelus dromedarius) lymphocytes and erythrocytes to heat-shock treatment. 2. 2. Lymphocytes of this organism characteristically have a higher resistance of general protein synthesis to elevated temperature in comparison with human lymphocytes. 3. 3. Camel lymphocytes exhibited strong induction of constitutively expressed 73 kDa heat-shock protein (hsp 73) after heat-shock but failed to synthesize an inducible member of the same family (hsp 72) at high temperatures. 4. 4. Nucleated camel erythrocytes do not synthesize any heat-shock proteins after temperature elevation. 5. 5. Western blot analysis, using polyclonal antibody for hsp 73, revealed high levels of this protein in camel lymphocytes and diminished, but significant, amounts of hsp 73 protein in the erythrocytes under normal physiological conditions. 6. 6. The role of 73 kDa hsp in providing thermotolerance of camel blood cells is discussed.

Investigation of the reversible inhibition of camel ( Camelus dromedarius) acetylcholinesterase by tetracaine

1. The camel erythrocyte membrane bound acetylcholinesterase (AChE) was extracted with the non-ionic detergent Triton X-100 and some of its kinetics parameters were studied. In addition the effect of tetracaine hydrochloride on AChE was also investigated. 2. The Michaelis-Menten constant ( K m ) for the hydrolysis of acetylthiocholine iodide was found to be 7 × 10 −5M and the V max was 21.2 μmol/hr/mg protein. 3. Tetracaine (0.025–0.80 mM) reversibly inhibited the AChE activity (25–82%) in a concentration-dependent manner, the ic 50 being about 0.12 mM. 4. The Lineweaver-Burk plot and its secondary plots indicated that the nature of this inhibition is of the linear mixed type. This mixed type inhibition system is considered to be composed of partial competitive and pure non-competitive in nature. 5. The values of K i(slope) and K ii(intercept) were estimated as 0.127 mM and 0.263 mM, respectively, by a secondary replot of primary double reciprocal plot of Lineweaver-Burk plot and Dixon plot. 6. K ii K i ratio shows that tetracaine has a greater affinity of binding to the active site than to a peripheral site.

High level agglutination of camel(Camelus dromedarius)erythrocytes by avian paramyxovirus serotype 1

Camel erythrocytes were suitable for haemagglutination (HA) and HA inhibition (HI) tests using four isolates of avian paramyxovirus type 1. The results were similar to those obtained with chicken erythrocytes.

Volume-dependent potassium transport in camel red blood cells.

In this study the volume-dependent, ouabain-resistant K+ influx and efflux in camel red blood cells were measured with the tracer 86Rb+. The results showed that the camel erythrocytes do not have the Na(+)-K+ cotransport. The cell swelling increases a ouabain-resistant K+ influx and shrinkage decreases it nearly two-fold. The swelling-stimulated K+ influx and efflux were chloride dependent. The anion dependence of K+ influx in swollen cells was as follows: Br- > Cl- > NO3. The pH-dependent curve for swelling-stimulated potassium influx, and the active K+ influx in camel erythrocytes were determined. The findings indicate that camel erythrocytes' potassium transport system has many similarities to other mammalian species.

Lipid composition of camel erythrocytes

Erythrocytes were prepared from heparinized blood obtained from camel, man and goat, and their osmotic behaviour in hypotonic solutions studied. Camel erythrocytes had the greatest osmotic stability followed by those of Man and goat. Erythrocyte lipids were extracted and found to be composed of free cholesterol and phospholipids. Fractionation of the phospholipids by TLC showed that phosphatidyl serine, phosphatidyl ethanolamine, sphingomyelin and phosphatidyl choline were the main phospholipid classes present.

Bending undulations and elasticity of the erythrocyte membrane: effects of cell shape and membrane organization

The undulatory excitations (flickering) of human and camel erythrocytes were evaluated by employing the previously used flicker spectroscopy and by local measurements of the autocorrelation function K (t) of the cell thickness fluctuations using a dynamic image processing technique. By fitting theoretical and experimental flicker spectra relative values of the bending elastic modulus Kc of the membrane and of the cytoplasmic viscosity eta were obtained. The effects of shape changes were monitored by simultaneous measurement of the average light intensity I0 passing the cells and by phase contrast microscopic observation of the cells. Evaluation of the cellular excitations in terms of the quasi-spherical model yielded values of Kc/R3(0) and mu.R0 (R0 = equivalent sphere radius) and allowed us to account (1) for volume changes, (2) for effects of surface tension and spontaneous curvature and (3) for the non-exponential decay of K (t). From the long time decay of K (t) we obtained an upper limit of the bending elastic modulus of normal cells of Kc = 2-3 x 10(-19) Nm which is an order of magnitude larger than the value found by reflection interference contrast microscopy (RICT, Kc = 3.4 x 10(-20) Nm, Zilker et al. 1987) but considerably lower than expected for a bilayer containing 50% cholesterol (Kc = 5 x 10(-19) Nm, Duwe et al. 1989). The major part of the paper deals with long time measurements (order of hours) of variations of the apparent Kc and eta values of single cells (and their reversibility) caused (1) by osmotic volume changes, (2) by discocyte-stomatocyte transitions induced by albumin and triflouperazine, (3) by discocyte-echinocyte transitions induced by expansion of the lipid/protein bilayer (by incubation with lipid vesicles) and by ATP-depletion in physiological NaCl solution, (4), by coupling or decoupling of bilayer and cytoskeleton using wheat germ agglutinin or erythrocytes with elliptocytosis and (5) by cross-linking the cytoskeleton using diamide. These experiments showed: (1) Kc and eta are minimal at physiological osmolarity and temperature and well controlled over a large range of these parameters. (2) Echinocyte formation does not markedly alter the apparent membrane bending stiffness. (3) During swelling the cell may undergo a transient discocyte-stomatocyte transition. (4) Strong increases of the apparent Kc and eta after cup-formation or strong swelling and deflation are due to the effect of shear elasticity and surface tension. Our major conclusions are: (1) The erythrocyte membrane exhibits a shear free deformation regime which requires ATP for its maintenance.(ABSTRACT TRUNCATED AT 400 WORDS)