Influence of dehydration and watering on camel red cell size: a scanning electron microscopic study

Schroter, R. C.; Filali, R. Z.; Brain, Anthony P.R.; Jeffrey, P.; Robertshaw, David

doi:10.1016/0034-5687(90)90118-i

Cited by 10 publications

(14 citation statements)

References 13 publications

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“…Alternatively, it is possible that the size and/or shape of red blood cells might be affected during dehydration in the presence of the angiotensin II receptor blocker indicating that the renin-angiotensin system may play a role in the morphology of red blood cells during dehydration in the camel. The change in plasma protein concentration with dehydration in the present study was greater (by approximately 5%) than in other reported studies 13,15,16 most likely because the period of dehydration was longer.…”

Section: Discussioncontrasting

confidence: 74%

Effect of Dehydration in the Presence and Absence of the Angiotensin Receptor Blocker Losartan on Blood Constituents in the Camel

Alhaj¹

2011

JMS

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Section: Discussioncontrasting

confidence: 74%

Effect of Dehydration in the Presence and Absence of the Angiotensin Receptor Blocker Losartan on Blood Constituents in the Camel

Alhaj¹

2011

JMS

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“…The value of μ affects the rate of cell shape change but not the stationary cell shape. This approach is much simpler than using a tessellated surface to represent the cell, and still general enough to capture the shape of blood platelets [3,29] and several RBCs [8,30], see Fig. 1A.…”

Section: Resultsmentioning

confidence: 99%

“…A) Scanning electron micrographs of Platelets and Erythrocytes [6][7][8], scale bar 1μm. B) The actin/spectrin cortex of platelets, EM from [9], scale bar 0.5μm.…”

Section: Figure Legendsmentioning

confidence: 99%

Balance of microtubule stiffness and cortical tension determines the size of blood cells with marginal band across species

Dmitrieff¹,

Alsina²,

Mathur³

et al. 2016

Preprint

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The fast blood stream of animals is associated with large shear stresses. Consequently, blood cells have evolved a special morphology and a specific internal architecture allowing them to maintain their integrity over several weeks. For instance, non-mammalian red blood cells, mammalian erythroblasts and platelets have a peripheral ring of microtubules, called the marginal band, that flattens the overall cell morphology by pushing on the cell cortex. In this article, we model how the shape of these cells stems from the balance between marginal band elasticity and cortical tension. We predict that the diameter of the cell scales with the total microtubule polymer, and verify the predicted law across a wide range of species. Our analysis also shows that the combination of the marginal band rigidity and cortical tension increases the ability of the cell to withstand forces without deformation. Finally, we model the marginal band coiling that occurs during the disc-to-sphere transition observed for instance at the onset of blood platelet activation. We show that when cortical tension increases faster than crosslinkers can unbind, the marginal band will coil, whereas if the tension increases slower, the marginal band may shorten as microtubules slide relative to each other. . This is not however the case for blood cells as they circulate freely within the fluid environment of the blood plasma. Red blood cells (RBC) and thrombocytes in non-mammalian animals [2,3], platelets and erythroblasts in mammals [4, 5] adopt a simple ellipsoidal shape (Fig. 1A). This shape is determined by two components: a ring of MTs, called the marginal band (MB), and a protein cortex at the cell periphery.In the case of platelets and non-mammalian red blood cells, both components are relatively well characterized (Fig. 1). The cortex is a composite structure made of spectrin, actin and intermediate filaments (Fig. 1B), and its complex architecture is likely to be dynamic [11][12][13]. It is a thin network under tension [14], that on its own would lead to a spherical morphology [15]. This effect is counterbalanced by the MB, a ring made of multiple dynamic MTs, held together by crosslinkers and molecular motors into a closed circular bundle [4, 16] (Fig. 1C). The MB is essential to maintain the flat morphology, and treatment with a MT destabilising agent causes platelets to round up [17]. It was also reported that when the cell is activated, the MB is often seen to buckle [3]. This phenomenon is reminiscent of the buckling of a closed elastic ring [18], but the MB is not a continuous structure of constant length.Indeed, an important feature of the MB is that is it made of multiple MTs, connected by dynamic crosslinkers. The rearrangement of connectors could allow MTs to slide relative to one another, and thus would allow the length of the MB to change. Secondly, MT growth or depolymerisation would also induce reorganisation. However, in the absence of sliding, elongation or shortening of single MTs would principally affect the thickness ...

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“…During periods of dehydration, body water, plasma fluid volume and blood flow are maintained (Manefield et al 1997) with the assistance of the osmotic nature of plasma proteins (Schmidt-Nielsen 1964;Maloiy 1972), hydrophilic haemoglobin (Bogner et al 1998) and stable, ellipsoid-shaped erythrocytes (Smith 2010 Australian Zoologist volume 35 2et al. 1979;Schroter et al 1990). The camel coat also helps conserve body water with effective insulation and efficient perspiration (Schmidt-Nielsen 1964, 1990.…”

Section: Vulnerability To a Biocidementioning

confidence: 99%

The odyssey of managing feral camels and their impacts—is there an Achilles' heel?

Coventry¹,

Edwards²,

Zeng³

2010

Australian Zoologist

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Camels Camelus dromedarius were first introduced into Australia in the 1840s for transport and haulage to enable recent settlers to explore and develop the arid interior of South Australia (SA) and the Northern Territory (NT), and later develop the northwest pastoral areas and goldfields of Western Australia (WA). After the introduction of rail and motorised transport in the 1920s, many camels were released, abandoned or escaped domestication to survive in the immediate arid areas. A NT population survey conducted in 2001 suggested that there was a minimum of 300,000 feral camels in Australia (Edwards et al. 2004) and the population was doubling every eight years. In 2008 the actual population size may have exceeded one million (Saalfeld and Edwards 2008). Adaptations to arid conditions, an absence of natural predators (Grigg 2007) and an absence of serious endemic disease (Brown 2004) have enabled feral camels to thrive on the arid rangelands of Australia. Emerging Problems Feral camels have assumed a pest status in Australia (McCloy and Rowe 2000; Department of the Environment and Heritage 2004; Grigg 2007) and are now widely distributed across arid regions (Figure 1), including the Simpson, Tanami, Great Victoria, Gibson and Great Sandy deserts. At current densities, feral camels are having measurable negative impacts on a range of values in these arid regions.

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Influence of dehydration and watering on camel red cell size: a scanning electron microscopic study

Cited by 10 publications

References 13 publications

Effect of Dehydration in the Presence and Absence of the Angiotensin Receptor Blocker Losartan on Blood Constituents in the Camel

Effect of Dehydration in the Presence and Absence of the Angiotensin Receptor Blocker Losartan on Blood Constituents in the Camel

Balance of microtubule stiffness and cortical tension determines the size of blood cells with marginal band across species

The odyssey of managing feral camels and their impacts—is there an Achilles' heel?

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