Different red cell populations in newborn, genetically low potassium sheep: Relation to hematopoietic, immunologic and physiologic differentiation

Valet, G.; Franz, George Philipp; Lauf, Peter K.

doi:10.1002/jcp.1040940211

Cited by 21 publications

(11 citation statements)

References 44 publications

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“…Between days 16 and 31 there was no significant increase in the numbers of Lp sites determined by electron microscopy in cells from fraction 1, although the number of sites had doubled in cells from fraction 4. Most of the cells in fraction 1 of the day 31 sample were extremely small both by Coulter counter and electron microscopic measurements and these presumably corresponded to the small cells described by Valet et al . (1978) .…”

Section: Detailed Study Ofdevelopmental Changes In One Lambsupporting

confidence: 71%

The transition from HK to LK phenotype in the red cells of newborn genetically LK lambs.

Tucker¹,

Smalley²,

Ellory³

et al. 1982

The Journal of General Physiology

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Section: Detailed Study Ofdevelopmental Changes In One Lambsupporting

confidence: 71%

The transition from HK to LK phenotype in the red cells of newborn genetically LK lambs.

Tucker¹,

Smalley²,

Ellory³

et al. 1982

The Journal of General Physiology

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“…Recent evidence by Valet and Lauf (1980) suggest that sheep stress reticulocytes are derived from different precursor cells than normal reticulocyte or they may be the consequence of a switch in gene expresson of normal cells.…”

Section: Discussionmentioning

confidence: 98%

“…Thus, the initial two populations disappear early in postnatal life and are gradually replaced by the third smaller type which persists throughout the adult life. In the postnatal guinea pig, two red cell populations are found (Valet et al, 1976). The initial population begins with a volume of 79$ and this population gradually disappears until it is entirely replaced by the adult red cell population at about 53 days after birth.…”

Section: Discussionmentioning

confidence: 99%

“…A probable explanation for the disparity between the results of newborn pigs and the results of sheep and rabbits may be due to the fact that reticulocytes from newborn pigs represent naturally occurring cells; whereas, cells from sheep and rabbits are so called "stress" reticulocytes. Recent evidence by Valet and Lauf (1980) suggest that sheep stress reticulocytes are derived from different precursor cells than normal reticulocyte or they may be the consequence of a switch in gene expresson of normal cells.…”

Section: Discussionmentioning

confidence: 99%

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Pig reticulocytes. IV. In vitro maturation of naturally occurring reticulocytes with permeability loss to glucose

Zeidler

Kim

1982

Journal Cellular Physiology

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Naturally occurring reticulocytes of week old piglets were used to characterize the maturation process under in vitro conditions. When the reticulocytes were suspended in tissue culture medium fortified with metabolic substrates, nearly all cells were viable after 24 hours incubation and usually more than 85% of the initial cell population survived after an 80 hour period. In cells maintained as long as a week in incubation, an adequate level of total adenine nucleotide with a large accumulation of IMP was found. In most cases, reticulocytes lose their reticular materials within two days and assume normal erythrocyte configuration. Concomitant with the morphological change, the cell volume decreases toward normal erythrocyte size, the extent of which can be accounted for by the intracellular loss of salt and accompanying water. As in the in vivo reticulocyte maturation process, reticulocytes undergoing in vitro maturation lose their membrane permeability to glucose. These findings suggest that the process of reticulocyte maturation occurring in cell culture approaches that which naturally occurs in vivo. Thus, these cells may be used to delineate the mechanism of the loss of membrane transport of glucose which normally occurs in the adult pig cells.

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“…Among these are their marked difference in size (sheep red cells are considerably smaller) and phospholipid composition (sheep erythrocytes lack phosphatidylcholine) (44,45). In addition, some strains of sheep have red blood cells whose intracellular ionic composition differs greatly from that of human erythrocytes (46).…”

Section: Figmentioning

confidence: 99%

Plicatamide, an Antimicrobial Octapeptide from Styela plicata Hemocytes

Tincu

Menzel²,

Azimov³

et al. 2003

Journal of Biological Chemistry

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Plicatamide (Phe-Phe-His-Leu-His-Phe-His-dc⌬DOPA), where dc⌬DOPA represents decarboxy-(E)-␣,␤-dehydro-3,4-dihydroxyphenylalanine, is a potently antimicrobial octapeptide from the blood cells of the solitary tunicate, Styela plicata. Wild type and methicillin-resistant Staphylococcus aureus (MRSA) responded to plicatamide exposure with a massive potassium efflux that began within seconds. Soon thereafter, treated bacteria largely ceased consuming oxygen, and most became nonviable. Native plicatamide also formed cation-selective channels in model lipid bilayers composed of bacterial lipids. Methicillin-resistant S. aureus treated with plicatamide for 5 min contained prominent mesosomes as well as multiple, small dome-shaped surface protrusions that suggested the involvement of osmotic forces in its antimicrobial effects. To ascertain the contribution of the C-terminal dc⌬DOPA residue to antimicrobial activity, we synthesized several analogues of plicatamide that lacked it. One of these peptides, PL-101 (Phe-Phe-His-Leu-His-Phe-HisTyr-amide), closely resembled native plicatamide in its antimicrobial activity and its ability to induce potassium efflux. Plicatamide was potently hemolytic for human red blood cells but did not lyse ovine erythrocytes. The small size, rapid action, and potent anti-staphylococcal activity of plicatamide and PL-101 make them intriguing subjects for future antimicrobial peptide design.Phe-Phe-His-Leu-His-Phe-His-dc⌬DOPA (plicatamide) 1 is a modified octapeptide found in the hemocytes of Styela plicata (1). In the preceding sequence, dc⌬DOPA indicates decarboxy-(E)-␣,␤-dehydro-3,4-dihydroxyphenylalanine. Although the sequence of plicatamide did not resemble a conventional antimicrobial peptide, we examined its antimicrobial properties because hemocytes are key participants in innate antimicrobial defenses. Despite its small size, plicatamide proved to be a potent, rapidly acting, and broad spectrum antimicrobial. We also prepared the following four synthetic analogues that differed from plicatamide only in their C-terminal residue: tyrosine amide in PL-101; tyrosine acid in PL-102; DOPA (3,4-dihydroxyphenylalanine) acid in PL-103; and DOPA-amide in PL-104. Of these octapeptides, PL-101 most closely simulated the antimicrobial properties of native plicatamide. This report will describe the effects of plicatamide on staphylococci. MATERIALS AND METHODS Peptide PurificationNative plicatamide was purified from freshly harvested hemocytes (blood cells) of S. plicata as described recently (1). We determined their peptide content either by performing quantitative amino acid analysis or by doing analytical reverse phase-HPLC on a C18 column and then computing and comparing the area under the curve (AUC) at 215 nm with the AUC of an appropriate standard previously subjected to quantitative amino acid analysis. Peptide SynthesisThe synthetic peptides used in our initial experiments were customsynthesized by Fmoc (N-(9-fluorenyl)methoxycarbonyl) chemistry at Research Genetics (Huntsville, AL) and puri...

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Different red cell populations in newborn, genetically low potassium sheep: Relation to hematopoietic, immunologic and physiologic differentiation

Cited by 21 publications

References 44 publications

The transition from HK to LK phenotype in the red cells of newborn genetically LK lambs.

The transition from HK to LK phenotype in the red cells of newborn genetically LK lambs.

Pig reticulocytes. IV. In vitro maturation of naturally occurring reticulocytes with permeability loss to glucose

Plicatamide, an Antimicrobial Octapeptide from Styela plicata Hemocytes

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