scholarly journals Blood-feeding in the young adult filarial wormsLitomosoides sigmodontis

Parasitology ◽  
2004 ◽  
Vol 130 (4) ◽  
pp. 421-428 ◽  
Author(s):  
T. ATTOUT ◽  
S. BABAYAN ◽  
A. HOERAUF ◽  
D. W. TAYLOR ◽  
W. J. KOZEK ◽  
...  
Keyword(s):  
Life Cycle ◽  
Young Adult ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Blood Feeding ◽  
Post Inoculation ◽  
Mongolian Gerbils ◽  
Litomosoides Sigmodontis ◽  
Precise Moment ◽  
Kinetics Of

In this study with the filarial modelLitomosoides sigmodontis, we demonstrate that the worms ingest host red blood cells at a precise moment of their life-cycle, immediately after the fourth moult. The red blood cells (RBC) were identified microscopically in live worms immobilized in PBS at 4 °C, and their density assessed. Two hosts were used: Mongolian gerbils, where microfilaraemia is high, and susceptible BALB/c mice with lower microfilaraemia. Gerbils were studied at 12 time-points, between day 9 post-inoculation (the worms were young 4th stage larvae) and day 330 p.i. (worms were old adults). Only the very young adult filarial worms had red blood cells in their gut. Haematophagy was observed between days 25 and 56 p.i. and peaked between day 28 and day 30 p.i. in female worms. In males, haematophagy was less frequent and intense. Similar kinetics of haematophagy were found in BALB/c mice, but frequency and intensity tended to be lower. Haematophagy seems useful to optimize adult maturation. These observations suggest that haematophagy is an important step in the life-cycle ofL. sigmodontis. This hitherto undescribed phenomenon might be characteristic of other filarial species including human parasites.

scholarly journals Four-Dimensional Characterization of the Babesia divergens Asexual Life Cycle, from the Trophozoite to the Multiparasite Stage

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
José Javier Conesa ◽  
Elena Sevilla ◽  
María Carmen Terrón ◽  
Luis Miguel González ◽  
Jeremy Gray ◽  
...  
Keyword(s):  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Binary Fission ◽  
Life Cycle Model ◽  
Cycle Model ◽  
Babesia Divergens ◽  
Complex Population ◽  
Vertebrate Hosts ◽  
Kinetics Of

ABSTRACT Babesia is an apicomplexan parasite of significance that causes the disease known as babesiosis in domestic and wild animals and in humans worldwide. Babesia infects vertebrate hosts and reproduces asexually by a form of binary fission within erythrocytes/red blood cells (RBCs), yielding a complex pleomorphic population of intraerythrocytic parasites. Seven of them, clearly visible in human RBCs infected with Babesia divergens, are considered the main forms and named single, double, and quadruple trophozoites, paired and double paired pyriforms, tetrad or Maltese Cross, and multiparasite stage. However, these main intraerythrocytic forms coexist with RBCs infected with transient parasite combinations of unclear origin and development. In fact, little is understood about how Babesia builds this complex population during its asexual life cycle. By combining cryo-soft X-ray tomography and video microscopy, main and transitory parasites were characterized in a native whole cellular context and at nanometric resolution. The architecture and kinetics of the parasite population was observed in detail and provide additional data to the previous B. divergens asexual life cycle model that was built on light microscopy. Importantly, the process of multiplication by binary fission, involving budding, was visualized in live parasites for the first time, revealing that fundamental changes in cell shape and continuous rounds of multiplication occur as the parasites go through their asexual multiplication cycle. A four-dimensional asexual life cycle model was built highlighting the origin of several transient morphological forms that, surprisingly, intersperse in a chronological order between one main stage and the next in the cycle. IMPORTANCE Babesiosis is a disease caused by intraerythrocytic Babesia parasites, which possess many clinical features that are similar to those of malaria. This worldwide disease is increasing in frequency and geographical range and has a significant impact on human and animal health. Babesia divergens is one of the species responsible for human and cattle babesiosis causing death unless treated promptly. When B. divergens infects its vertebrate hosts, it reproduces asexually within red blood cells. During its asexual life cycle, B. divergens builds a population of numerous intraerythrocytic (IE) parasites of difficult interpretation. This complex population is largely unexplored, and we have therefore combined three- and four-dimensional imaging techniques to elucidate the origin, architecture, and kinetics of IE parasites. Unveiling the nature of these parasites has provided a vision of the B. divergens asexual cycle in unprecedented detail and is a key step to develop control strategies against babesiosis.

Kinetics of Na-Li exchange in high and low K sheep red blood cells

1989 ◽  
Vol 257 (1) ◽  
pp. C58-C64 ◽  
Author(s):  
K. H. Ryu ◽  
N. C. Adragna ◽  
P. K. Lauf
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Cell Types ◽  
Sheep Red Blood Cells ◽  
High K ◽  
Ping Pong ◽  
Order Of Magnitude ◽  
Low K ◽  
Kinetics Of ◽  
System Operating

The kinetic parameters and transport mechanism of Na-Li exchange were studied in both low K (LK) and high K (HK) sheep red blood cells with cellular Na [( Na]i) and Li concentrations [( Li]i) adjusted by the nystatin technique (Nature New Biol. 244: 47-49, 1973 and J. Physiol. Lond. 283: 177-196, 1978). Maximum velocities (Vm) for Li fluxes and half-activation constants (K1/2) for Li and Na of the Na-Li exchanger were determined. The K1/2 values for both Li and Na appeared to be similar in both cell types, although they were about two to three times lower on the inside than on the outside of the membrane. Furthermore, the K1/2 values for Li were at least an order of magnitude smaller than those for Na, suggesting substantial affinity differences for these two cations. The Vm values for Li fluxes, on the other hand, appear to be lower in HK than in LK cells. When Na and Li fluxes were measured simultaneously, a trans stimulatory effect by Na on Li fluxes was observed. From measurements of Li influx at different concentrations of external Li and different [Na]i, the ratio of the apparent Vm to the apparent external Li affinity was calculated to be independent of [Na]i for both types of sheep red blood cells. Similar trans effects of external Na were observed on Li efflux at varying [Li]i. These results are expected for a system operating by a “ping-pong” mechanism.

Differentiation of Na(+)-K+ pumps of low-K+ sheep red blood cells is promoted by Lp membrane antigens

1993 ◽  
Vol 265 (1) ◽  
pp. C99-C105 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Rat Kidney ◽  
Striking Increase ◽  
Sheep Red Blood Cells ◽  
High K ◽  
Membrane Antigens ◽  
Low K ◽  
Kinetics Of

Na(+)-K+ pumps of red blood cells from sheep of the low-K+ (LK) phenotype undergo differentiation during circulation, manifested in part by a striking increase in sensitivity to inhibition by intracellular K+ (Ki). Pumps of red blood cells from sheep from the allelic phenotype, high K+ (HK), do not undergo this type of maturation. The hypothesis was tested that the Lp antigen, found on LK but not HK cells, is responsible for the maturation of LK pumps. Lp antigens have been shown to inhibit LK pumps because anti-Lp antibody stimulates the pumps by relieving inhibition by the antigen. Lp antigens were recently shown to be molecular entities separate from Na(+)-K+ pumps [Xu, Z.-C., P. Dunham, J. Munzer, J. Silvius, and R. Blostein. Am. J. Physiol. 263 (Cell Physiol. 32): C1007-C1014, 1992]. The test of the hypothesis was to modify the Lp antigens of immature LK red blood cells with two kinds of treatments, anti-Lp antibody and trypsinization (which cleaves Lp), and to observe the effects of these treatments on maturation of pumps during culture of the cells in vitro. Both of these treatments prevented the maturation of the kinetics of the pumps to the Ki-sensitive pattern, supporting the hypothesis that interaction of the pumps with Lp antigens is responsible for the maturation of the pumps. Strong supportive evidence came from experiments on Na(+)-K+ pumps from rat kidney delivered into immature LK sheep red blood cells by microsome fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The Role of Cell Adhesion in the Malaria Life Cycle: From Gliding Sporozoites to Rolling Adhesion of Infected Red Blood Cells

2017 ◽  
Vol 112 (3) ◽  
pp. 330a
Author(s):  
Ulrich S. Schwarz ◽  
Friedrich Frischknecht ◽  
Michael Lanzer ◽  
Anna Battista ◽  
Christine Lansche ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells

Comparison between Ca2+-induced scrambling of various fluorescently labelled lipid analogues in red blood cells

2002 ◽  
Vol 362 (3) ◽  
pp. 741-747 ◽  
Author(s):  
David W. C. DEKKERS ◽  
Paul COMFURIUS ◽  
Edouard M. BEVERS ◽  
Robert F. A. ZWAAL
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Red Blood Cells ◽  
Phospholipase D ◽  
Blood Cells ◽  
Amino Group ◽  
Flip Flop ◽  
Putative Membrane Protein ◽  
Kinetics Of

Treatment of red blood cells with calcium and ionomycin causes activation of the lipid scramblase, a putative membrane protein catalysing flip-flop of (phospho)lipids. Various fluorescent 1-oleoyl-2-[6(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] caproyl (C6-NBD) analogues were tested for transbilayer movement across the plasma membrane of red blood cells. Among these phospholipid analogues were phosphatidylgalactose, phosphatidylmaltose and phosphatidylmaltotriose, which were obtained from C6-NBD-phosphatidylcholine by phospholipase D-catalysed transphosphatidylation. The inward movement after the onset of scrambling was monitored by extraction of the non-internalized probe with BSA. We demonstrate that both the amino group and the size of the headgroup determine the kinetics of lipid scrambling, and that lipids with a ceramide backbone migrate much more slowly than glycerophospholipids with the same headgroup.

scholarly journals Kinetics of Cl-dependent K fluxes in hyposmotically swollen low K sheep erythrocytes.

1991 ◽  
Vol 97 (2) ◽  
pp. 173-193 ◽  
Author(s):  
E Delpire ◽  
P K Lauf
Keyword(s):  
Red Blood Cells ◽  
Kinetic Study ◽  
Kinetic Parameters ◽  
Blood Cells ◽  
Red Cells ◽  
Maximal Velocity ◽  
Temperature Dependent ◽  
Low K ◽  
Kinetics Of ◽  
External K

A detailed kinetic study of K:Cl cotransport in hyposmotically swollen low K sheep red blood cells was carried out to characterize the nature of the outwardly poised carrier. The kinetic parameters were determined from the rate of K efflux and influx under zero-K-trans conditions in red cells with cellular K altered by the nystatin method and with different extracellular K or Rb concentrations. Although apparent affinities for efflux and influx were quite similar, the maximal velocity for K efflux was approximately two times greater than for influx. Furthermore, at thermodynamic equilibrium (i.e., when the ion product of K and Cl within the cell was equal to that outside) a temperature-dependent net K efflux was observed, approaching zero only when the external product reached approximately two times the internal product. The binding order of the ions to the transporter was asymmetric, being ordered outside (Cl binding first, followed by K) and random inside. K efflux but not influx was trans-inhibited by KCl. Trans inhibition of K efflux was used to verify the order of binding outside: trans inhibition by external Cl occurred in the absence of external K, but not vice versa. Thus K:Cl cotransport is kinetically asymmetric in hyposmotically swollen low K sheep red cells.

Oxygen transfer kinetics of red blood cells of the turtle Pseudemys scripta elegans

1989 ◽  
Vol 75 (3) ◽  
pp. 371-384 ◽  
Author(s):  
K. Yamaguchi ◽  
M.L. Glass ◽  
P. Scheid ◽  
J. Piiper
Keyword(s):  
Red Blood Cells ◽  
Oxygen Transfer ◽  
Blood Cells ◽  
Pseudemys Scripta ◽  
Kinetics Of

Kinetics of red blood cells following hemolysis

1969 ◽  
Vol 23 (3) ◽  
pp. 475-491 ◽  
Author(s):  
George H. Weiss ◽  
Gershom Zajicek
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Kinetics Of

scholarly journals Inside Scoop on Outside Proteins

2013 ◽  
Vol 82 (3) ◽  
pp. 921-923
Author(s):  
Jeffrey D. Dvorin
Keyword(s):  
Immune Response ◽  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Current Issue ◽  
Detailed Examination ◽  
Content Type ◽  
Human Malaria ◽  
Essential Step

ABSTRACTInvasion into red blood cells is an essential step in the life cycle of parasites that cause human malaria. Antibodies targeting the key parasite proteins in this process are important for developing a protective immune response. In the current issue, Boyle and colleagues provide a detailed examination ofPlasmodium falciparuminvasion and specifically illuminate the fate of surface-exposed parasite proteins during and immediately after invasion.

Sign in / Sign up

Export Citation Format

Share Document