The Camel's Erythrocyte

Kinetics of the reaction of intraerythrocytic haemoglobin by single cell microspectroscopy: effect of shape and osmolarity

“…Furthermore, if the progress curves are analyzed in terms of the slope (i.e. the absorbance change Table 1 CO dependence of l/tr,z (s-l) for CO recombination to intracellular Hb at different osmotic pressures tration, which is higher in camel RBC than in human RBC [5], and which is known to modulate the diffusion rate constant for CO [9]. This role of the intracellular Hb concentration seems to be also supported by the observation that, at [CO] < 0.5 mM , a decrease of the medium osmolarity (and (where &-Ib is the absorbance of deoxyHb at 430 nm, in our case) k yields, independent of the total amount of intracellular Hb, a measure of the diffusion velocity of CO from the extracellular medium to the observation spot (expressed as the ratio of the absorbance change per s (AA/s).…”

“…l-2 pm3), the possible role of intracellular Hb concentration on the recombination rate process may be important, and therefore we have attempted to probe the effect of this variable. To achieve a change in the RBC volume through changes in the osmolarity of the extracellular medium, we have extended the investigation to low osmotic pressure, and thus have used RBC from Camelus dromedarius, which are known to remain intact even at an osmolarity as low as 50 mosm/l, that is 6-times below the iso-osmotic pressure (280-290 mosm/l), swelling in volume up to twice the normal value [5].…”

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“…In fact, according to Bogner et al (2005), the proportion of osmotically non-removable water in camel erythrocytes is nearly 3-fold greater than that in human RBC (approximately 65 vs approximately 20%). On the other hand, erythrocytes of camels show a very low water contents (1.1 -1.3 g water/g dry mass) (Yagil et al, 1974;Weiser et al, 1992;Perk, 2000) and a difference in the major intrinsic membrane water-soluble protein ''spectrin'' which appears to be very tightly bound to the membrane by comparison to those of humans and bovine species (Ralston, 1975). The camel RBC subjected to H 2 O 2 showed an increase of hemolysis, membrane fragility and TBARS production (table 2).…”

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“…In the desert, black Bedouin goats may consume an amount of water exceeding 40 % of their dehydrated body weight (Shkolnik et al 1980). Three theories have been presented so far to explain the ways ruminants and camels circumvent the osmotic hazards posed by their enormous drinking capacity: (i) red blood cells' osmotic stability (Perk, 1963;Yagil, Sod-Moriah & Meyerstein, 1974;Etzion et al 1984); (ii) the rumen as a protective osmotic mechanism (Hoppe et al 1976;Chosniak & Shkolnik, 1977); and (iii) recycling of hypotonic fluid to the foregut by the hepato-salivary route (Silanikove, 1989b(Silanikove, , 1991.…”

“…Red blood cell osmotic stability The camel's red blood cells were shown to be stable in vitro to extremely hypotonic (50 mM) salt solutions (Ponder, Frankline & Charipper, 1928;Perk, 1963). This led several investigators to relate the camel's ability to undergo rapid rehydration to the osmotic stability of its red blood cells (Perk, 1963;Yagil et al 1974;Etzion et al 1984).…”