Camel Erythrocytes Research Articles

Marginal bands in camel erythrocytes

The elliptical, anucleate erythrocytes of camels have been examined for the presence of marginal bands and their constituent microtubules. Lysis of erythrocytes under microtubule-stabilizing conditions readily revealed marginal bands in at least 3 % of the cells, as observed by phase-contrast and darkfield light microscopy. Microtubules plus a marginal band-encompassing network of material are visible in lysed cell whole mounts with transmission electron microscopy. Marginal band microtubules are also evident in electron micrographs of thin-sectioned camel erythrocytes identifiable as reticuloyctes on the basis of submaximal electron density (reduced haemoglobin iron content) and presence of polysomes. The results suggest that marginal bands may be involved in morphogenesis of camel erythrocytes but are not required for maintenance of their ellipticity after cells are fully differentiated.

Permeability of erythrocytes to glycerol and its acylated derivatives in the camel and dog

1. 1. Glycerol and glyeerol derivatives transport was compared in human, dog and camel erythrocytes. 2. 2. The camel erythrocytes had the slowest glyeerol transport, that of the dog erythrocytes was also slow, while the quickest transport occurred in human erythrocytes. 3. 3. In glyeerol mono-, di- and triacetates the transport in camel and dog erythrocytes increased until in the triacetate the quickest transport was found. 4. 4. Addition of copper ions had no inhibiting effect on glyeerol transport in camel erythrocytes but a striking effect was seen in human erythrocytes. 5. 5. Changes in pH greatly affected transport in camel erythrocytes, a decline in pH enhanced and an increase in pH slowed the transport. Storage of camel erythrocytes did not affect the glyeerol transport in camel erythrocytes. 6. 6. It is concluded that the mechanism of glyeerol transport in camel erythrocytes is one of a non-facilitated diffusion.

The erythrocyte membrane site for the effect of temperature on osmotic fragility

The osmotic fragility of human erythrocytes is well known to decrease as the temperature is elevated. The cellular site for the temperature effect was studied by assessing possibles roles of hemoglobin and of membrane lipids and by taking advantage of the unique response of camel erythrocytes to temperature. It is concluded that the erythrocyte membrane is the site for the temperature effect on osmotic fragility. The human erythrocyte is likely to rupture in protein-lipid boundary regions in the membrane, from which cholesterol is apparently excluded.

Unique properties of the camel erythrocyte membrane: II. Organization of membrane proteins

Camel erythrocyte membranes are distinguished by some unique properties of stability and composition. Notable is their abundance in proteins (protein: lipid ratio of 3 : 1). Membrane proteins of camel erythrocytes were compared with those of human erythrocytes, which have been intensively investigated. Proteins were extracted with various aqueous media (EDTA, alkaline or high ionic strength) and with ionic and non-ionic detergents and were analyzed by gel electrophoresis. In membranes of camel erythrocytes, the peripheral proteins constitute, proportionally, a much smaller fraction of total proteins than in the human erythrocyte, while their distribution is identical per unit of surface area. The camel erythrocyte membrane is particularly rich in integral proteins and in intramembranous particles. The proteins in this membrane are more closely organized than in the human system, as revealed by crosslinking and freeze-etching studies. It is proposed that protein-protein interaction of integral proteins, presumably constituting an “integral skeleton”, is a dominant structural feature stabilizing the camel erythrocyte membrane.

Proteins of the camel erythrocyte membrane

Electrophoresis on polyacrylamide gels containing dodecyl sulphate has revealed that the major proteins of the camel erythrocyte membrane are similar to those of the human and bovine species in both electrophoretic mobility and relative abundance. The major difference lies in the major intrinsic membrane protein of molecular weight approx. 100 000. In the camel, this protein has a higher apparent molecular weight than in the human and bovine species. The very high molecular weight water-soluble protein “spectrin” appears to be very tightly bound to the camel erythrocyte membrane, and is only partially extracted after prolonged low ionic strength dialysis. Total release of spectrin is only achieved by means of more drastic treatment such as incubation with urea, guanidine hydrochloride, sodium hydroxide or p-chloromercuribenzoate. Concurrent with the total release of spectrin, the camel cells undergo a shape change from flat ellipsoids to spheres, suggesting an important shape-maintaining role for spectrin in the erythrocytes of this species.

Morphology of Camel and Llama Erythrocytes as Viewed with the Scanning Electron Microscope

SUMMARY Morphologic features of erythrocytes from two camels and a llama were studied using the scanning electron microscope. The distinctive elliptical erythrocytes of both animals appeared to be thin and wafer-like. Their surface was generally smooth and the cellular outline was regular. An occasional camel erythrocyte exhibited a shallow surface depression near the margin of the cell. A rare camel and llama erythrocyte appeared spatulate. The thin wafer-like form of the camel erythrocytes was congruous with their known resistance to osmotic lysis.

Unique properties of the camel erythrocyte membrane

In view of the exceptionally high osmotic stability of camel erythrocytes, several aspects of the membranes were examined. 1. 1. Added linolenoyl sorbitol increased the osmotic stability of camel erythrocytes to only one-third of the increase of human erythrocytes similarly treated. Human, hamster, rat and sheep erythrocytes exhibited similar time courses of lysis by sonic irradiation, while camel erythrocytes were distinctly more stable. Unlike its effect on human erythrocytes, vinblastin did not impair the osmotic stability of camel erythrocytes. 2. 2. Lipid composition of camel erythorcytes was analyzed. Lipid content per packed cell volume, phospholipid:cholesterol molar ratio, phospholipid composition as well as composition of the phospholipid fatty acids were all close to values reported for other species. 3. 3. Ghosts prepared from camel erythrocytes had a protein:lipid ratio of 3.0, compared with a ratio of 1.25 in human erythrocyte ghosts, and showed a higher proportion of proline and arginine but lower proportion of glutamic acid. 4. 4. It is proposed that the unique lipoprotein structure of the camel erythrocyte membrane may account for the unusual features of these erythrocytes.

Comparative studies of the respiratory functions of mammalian blood. III. Fetal and adult dromedary camel blood

Blood samples were obtained from two adult camels and one fetal camel of approximately 7 months gestational age. As in other mammalian species, fetal blood has a higher oxygen affinity than adult blood and there was a higher hemoglobin concentration in fetal blood than in the mother's blood. Fetal erythrocytes are larger than adult erythrocytes. Methemoglobin concentration is somewhat higher in fetal blood than in adult blood but seems to be in the normal range. Camel erythrocytes have a greater resistance to hemolysis by hypotonic saline than human erythrocytes. Analysis of the characteristics of camel hemoglobin showed no difference between the pigment of adults and that of a 7 months fetus with regard to hemoglobin electrophoresis, alkali denaturation or the rate of oxidation by potassium ferricyanide. On the other hand, red cells from the fetal camel had a higher activity in reducing methemoglobin and a lower activity of carbonic anhydrase than that found in the blood of the adult animal.

Osmotic hemolysis of the camel's erythrocytes. I. A microcinematographic study

AbstractGradual osmotic hemolysis of camel erythrocytes was observed by means of phase contrast microscopy and recorded by microcinematographic methods. It was found that the normal ovoid erythrocytes become spherical when the solution surrounding the erythrocytes is diluted ionically, and they swell to 240% of the initial volume. After hemolysis the erythrocyte membranes (ghosts) revert to their original oval form.Comparative studies of osmotic fragility tests on red blood cells of growing and adult camels showed the presence of two distinct cell populations in growing camels. One corresponds to the adult blood. The second cell type is more resistant to osmotic pressure and is found only in the young camel.

II. Mitt.: Zur Immunmorphologie der „Plaque-bildenden“ Milchflecken im Mäuseomentum

Mice were immunized by intraperitoneal injection of sheep erythrocytes. The morphology of the cells which consecutively accumulate in non-vascularized milky spots has been studied on stained omental spreads. Macrophages, lymphocytes, large pyroninophilic cells, plasma cells, mast cells and eosinophilic granulocytes were found to be present in varying numbers depending on the stage of the immune process. Mast cells and eosinophilic granulocytes appeared in appreciable numbers not before several weeks after immunization. Milky spots - caused by intraperitoneal stimulation with two morphologically different types of erythrocytes (pigeon-sheep; camel-sheep) were shown to produce antibodies against both cell types. This was demonstrated with a modification of the Jerne - plaque-technique. By contrast, single cells, isolated from doubly-producing milky spots released antibody directed against either sheep or pigeon resp. camel erythrocytes. Thus far no doubly producing single cells have been found.

Studies In Louping-Ill. (An Encephalomyelitis of Sheep.)

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.