Erythrocyte Surface Sialic Acid Research Articles

Clinicopathological Parameters and Sialyltransferase Activity in Trypanosoma Congolense-Infected Sheep

Cleavage of erythrocyte surface sialic acid (SA) by the sialidase produced by trypanosomes is implicated in the pathogenesis of anaemia in African animal trypanosomiasis (AAT). Sialyltransferase (ST) mediates the attachment of SA to cell surface glycoproteins and glycolipids of desialylated erythrocytes. ST activities in Trypanosoma congolense-infected sheep and control groups were investigated and variations in their physio-biochemical properties were evaluated. Six (6) apparently healthy Nigerian Yankassa breed of sheep comprising of T. congolense-infected (n=3) and non-infected (n=3) groups were used for the experiment. Parasitaemia and packed cell volume (PCV) were determined daily over a 5-week period. Enzyme kinetics of partially purified ST from the thyroid gland were also evaluated. Anaemia (mean PCV= 18.83±0.71%) was observed in the T. congolense-infected sheep when compared with the non-infected control group (mean PCV 39.75±0.35%) and the observed differences were significant (p < 0.05) after five weeks post infection. Variations were also observed in the physio-biochemical properties (pH, temperature, activation energy) of the ST isolated from the T. congolense-infected and control sheep. This finding is believed to have been an induced response by the host to parasite’s activity and could be exploited further as a possible target in the control of AAT.

Correlation between some haematological parameters, leukocyte ratios, parasitaemia and their prognostic value in canine trypanosomosis

African trypanosomosis is a disease of high economic importance in animals and humans caused by an apicomplexan haemoparasite of the genus Trypanosoma. Canine trypanosomosis is relatively common in Nigeria because of the high prevalence of the insect vector. The haematology, erythrocyte, and serum sialic acid levels of dogs experimentally infected with Federe strain of Trypanosoma brucei brucei was studied in a total of five (5) 4-month old dogs. Three of the dogs were randomly selected and inoculated subcutaneously with 1 × 106 of T. brucei, while the remaining two dogs served as the uninfected control. The parasitaemia, packed cell volume (PCV), total and differential white blood cell count, erythrocyte surface sialic acid (ESSA) and free serum sialic acid (FSSA) were determined twice a week. The lymphocyte/monocyte ratio (LMR) and neutrophil/lymphocyte ratio (NLR) were calculated. The infected dogs had a significantly lower PCV, total white blood cell count (TWBC), LMR and ESSA compared to the uninfected control group. There was a strong positive correlation between NLR and PCV decrease, moderate negative correlation between LMR and PCV decrease, strong negative correlation between LMR and ESSA changes, and a moderate positive correlation between ESSA changes and parasitaemia. The higher NLR in trypanosome infection associated with decreasing levels of PCV indicates a poor prognosis, and NLR may be a useful tool in estimating trypanosomosis effect on PCV in dogs. Similarly, the moderate negative and strong negative correlations between LMR with decreases in PCV and ESSA respectively indicates poor prognosis in the response to trypanosomosis in dogs. Thus, NLR, LMR and ESSA levels can be used as markers for predicting disease outcome in trypanosome infection in dogs. This is, however, not the case with parasitaemia as the clinico-pathologic effect of trypanosomosis cannot be estimated from the level of parasitaemia alone.

Molecular occurrence of trypanosomes, erythrocyte and serum sialic acid concentrations of Muturu and Bunaji cattle in Benue State, Nigeria

One hundred each, of Muturu and Bunaji cattle were screened, using polymerase chain reaction (PCR), for trypanosomes in Makurdi and Gboko Local Government Areas of Benue State, Nigeria. Erythrocyte surface sialic acid (ESSA) and free serum sialic acid (FSSA) concentrations were determined and compared in both breeds with the aim of providing baseline data for research and diagnostic purposes. Five per cent (5%) and 23% of the Muturu and Bunaji cattle, respectively, were positive for trypanosomes. The result at p=0.005 was significantly different, with p value of 0.0002 and odd ratio of 0.1762. The Trypanosoma species circulating in Benue State, as detected in the two breeds of cattle, were Trypanosoma congolense, T. vivax, T. brucei and T. evansi. This study, therefore, reports for the first time a natural infection of cattle with T. evansi and the use of a novel PCR in the diagnosis of trypanosome infections in cattle in Benue State, Nigeria. The determination of the ESSA and FSSA concentrations in Muturu cattle in Nigeria is also reported for the first time. The Muturu cattle have a significantly higher ESSA than the Bunaji cattle, this may be responsible for their relative trypanotolerance.

Effects of Vitamins C and E on Erythrocyte Osmotic Fragility, Serum Malondialdehyde concentrations and Surface Erythrocyte Sialic Acid in Rams following Road Transportation

This study was designed to investigate the effect of administration of combination of vitamin C + E and vitamin C alone on erythrocyte osmotic fragility (EOF), serum malondialdehde (MDA) and surface sialic acid (SSA) concentration in road transported rams. Twenty one (21) rams were used for the study. On the day of transportation, 7 rams (Group 1) were orally and individually administered with vitamin C (Juhel® Nigeria Ltd.) at the dose of 250 mg/kg dissolved in 10 ml of water and also vitamin E (100 mg DL-α-tocopherol) (Patterson Zoochonist Ltd. Nigeria) at the dose of 75 mg/kg, per os while another 7 rams (Group 2) was administered orally and individually with vitamin C (250 mg/kg) only. The 3rd group (7 rams) was the control, and they were administered orally and individually with only 10 ml of sterile water. The results indicated that the percentage haemolysis after 8 hours (end of the journey) increased in the entire treatment group which was significantly (P 0.05) different. There was progressive decline in the mean SSA concentrations in the control group with a value of 6.00 ± mg/ml at the end of the journey (8 h) which was not significantly (P > 0.05) different but had higher decrease of 17.43 % as against 4.52 % and 5.56 % in group 1 and 2 respectively. In conclusion the findings in this study have provided an insight into the role of erythrocyte SSA and ROS in explaining haemolysis associated with road transported ram and the possible ameliorative roles of Vitamins C and E on haemolysis

Survey for Serum Neuraminidase, Free and Erythrocyte Surface Sialic Acid from Chickens Vaccinated Against Newcastle Disease and the Unvaccinated Chickens Reared under Semi-Intensive Management System

Survey for Serum Neuraminidase, Free and Erythrocyte Surface Sialic Acid from Chickens Vaccinated Against Newcastle Disease and the Unvaccinated Chickens Reared under Semi-Intensive Management System

Erythrocyte surface sialic acid levels of clinically healthy mongrel and exotic (alsatian and terrier) breeds of dogs

The erythrocyte surface sialic acid concentration of clinically healthy mongrel and exotic (Alsatian i.e. German shepherd and Terrier) breeds of dogs was analyzed in order to determine their role in the genetic resistance of these breeds of dogs to diseases that cause anaemia. The mean erythrocyte surface sialic acid (ESA) concentration was 57.08 +/- 1.67, 34.50 +/- 2.30 and 20.20 +/- 3.54 mg/dl for Mongrel, Alsatian (German shepherd) and Terrier breeds of dogs, respectively, on acid hydrolysis. The mean values of ESA obtained following enzymic hydrolysis of haemoglobin-free erythrocyte membranes using Clostridium chauvoei (Jakari strain) sialidase were 49.08 +/- 0.41, 30.97 +/- 1.82 and 18.64 +/- 0.75 mg/dl for Mongrel, Alsatian (German shepherd) and Terrier dogs respectively. When Trypanosoma vivax sialidase was used the ESA values obtained were 50.81 +/- 0.37, 41.70 +/- 0.94 and 19.65 + 0.65 mg/dl for Mongrel, Alsatian (German shepherd) and Terrier breeds of dogs respectively. This represents a statistically significant difference (P < 0.001) between the mean ESA concentration of all the breeds of dogs investigated in this study. The higher mean ESA concentration in Mongrel dogs, compared to the exotic breeds may be responsible for their resistance to disease conditions, whose aetiologic agents produce neuraminidase and also cause anaemia.

Comparative studies on erythrocyte sialic acid levels in apparently healthy indigenous Nigerian poultry species

The erythrocyte surface sialic acid levels of 200 apparently healthy indigenous Nigerian poultry species (pigeons, guinea fowls, ducks and chickens, n = 50 for each species) presented for slaughter at a poultry abattoir in Zaria, Nigeria was determined. Other parameters determined were packed cell volume (PCV) and plasma total protein (TP) concentration. The mean erythrocyte surface sialic acid concentration of pigeons, guinea fowls, ducks and chickens were 7.88 +/- 2.51, 14.6 +/- 2.51, 17.6 +/- 2.51 and 14.2 +/- 2.51 mg mg(-1) respectively. There was a statistically significant difference between the mean erythrocyte surface sialic acid concentration of all the species of poultry sampled (P < 0.05). The high erythrocyte surface sialic acid concentration in the indigenous Nigerian poultry species could be responsible for their resistance to infectious diseases, whose aetiologic agents produce neuraminidases. The mean PCV of the pigeons, guinea fowls, ducks and chickens were 46.22 +/- 6.91, 38.24 +/- 6.91, 36.50 +/- 6.91 and 36.46 +/- 6.91% respectively. The difference between the mean PCV values of pigeons on the one hand and guinea fowls, ducks and chickens on the other was statistically significant (P < 0.05). A negative correlation (r = -0.36, P < 0.05) between mean erythrocyte surface sialic acid concentrations and PCV was observed, i.e. the birds with the highest mean PCV values had the lowest levels of erythrocyte surface sialic acid. There was no correlation between TP concentration and either erythrocyte surface sialic acid concentration or PCV values. It is suggested, based on this study, that erythrocyte sialic acid types in these species should be determined, as the results may be vital in selective breeding.

Blackleg in ruminants.

Abstract Blackleg is a per acute or acute and fatal disease of cattle and sheep caused by Clostridium chauvoei Jakari, Vom and K76 strains in Nigeria, strains NCTC 8070 and 8361 in UK, strain 49 in India and other parts of Asia, strain NC08596 in Germany and other parts of Europe and America, strains ch.16 and ch.22 in Mozambique and Tanzania and strain Awasa in Ethiopia, respectively. The haematological and biochemical changes observed in ruminants with blackleg include haemoconcentration (increased packed cell volume, haemoglobin concentration, red blood cell counts, and total plasma protein concentration), increased erythrocyte sedimentation rate (ESR), decrease in total and differential leucocyte counts (leucopaenia, panleucopaenia i.e. lymphopaenia, neutropaenia, eosinopaenia and monocytopaenia), thrombocytopaenia, increased plasma neuraminidase activity, increased erythrocyte surface and plasma sialic acid concentration, increased levels of serum lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and increased creatine kinase (CK) activity. The leucopaenia and decrease in differential leucocyte counts, increase in plasma sialic acid concentration and decrease in erythrocyte surface sialic acid levels were attributed to the action of neuraminidase, whose activity is increased in the plasma in clinical blackleg. The neuraminidase produced by C. chauvoei is reported to possibly play a significant role in the inflammation and vascular permeability which are observed in blackleg. The pathological changes observed in cattle, sheep and deer with blackleg are essentially similar and are discussed. Some herbal remedies ( Tamarindus indicus and Combretum fragrans ) have been used by the transhumance (nomadic) Fulani pastoralists of rural Nigeria to successfully treat the disease. The economic losses of ruminants to the disease have not been quantified in most countries of the world, but in Nigeria, annual losses of cattle to it have been estimated at US$4.3 million. Vaccination has remained the best control strategy against the disease, which is endemic in Africa, USA, Central and Southern America, Asia and Europe.

Adherence of erythrocytes during exflagellation of Plasmodium falciparum microgametes is dependent on erythrocyte surface sialic acid and glycophorins.

Malaria male gametocytes within a newly ingested infected blood meal in the mosquito midgut emerge from erythrocytes and extrude approximately eight flagellar microgametes in a process termed exflagellation. In culture, and in blood removed from infected patients, emerging microgametes avidly adhere to neighboring uninfected and infected erythrocytes, as well as to emerged female macrogametes, creating "exflagellation centers". The mechanism of erythrocyte adherence is not known nor has it been determined for what purpose microgametes may bind to erythrocytes. The proposition of a function underlying erythrocyte adherence is supported by the observation of species-specificity in adhesion: microgametes of the human malaria Plasmodium falciparum can bind human erythrocytes but not chicken erythrocytes, whereas avian host Plasmodium gallinaceum microgametes bind chicken but not human erythrocytes. In this study we developed a binding assay in which normal, enzyme-treated, variant or null erythrocytes are identified by a cell surface fluorescent label and assayed for adherence to exflagellating microgametes. Neuraminidase, trypsin or ficin treatment of human erythrocytes eliminated their ability to adhere to Plasmodium falciparum microgametes, suggesting a role of sialic acid and one or more glycophorins in the binding to a putative gamete receptor. Using nulls lacking glycophorin A [En(a-)], glycophorin B (S-s-U-) or a combination of glycophorin A and B (Mk/Mk) we showed that erythrocytes lacking glycophorin B retain the ability to bind but a lack of glycophorin A reduced adherence by exflagellating microgametes. We propose that either the sialic acid moiety of glycophorins, predominantly glycophorin A, or a more complex interaction involving the glycophorin peptide backbone, is the erythrocyte receptor for adhesion to microgametes.

Biochemical Differences (O-Acetyl and Glycolyl Groups) in Erythrocyte Surface Sialic Acids of Trypanotolerant N'dama and Trypanosusceptible Zebu Cattle

Differences in the distribution and concentration of O-acetyl and glycolyl groups in erythrocyte sialic acids of trypanotolerant N'dama and trypanosusceptible Zebu cattle were investigated. Erythrocyte surface sialic acid concentrations were 25.4 +/- 5.5 mg per dl and 5.9 +/- 0.97 mg per dl in N'dama and Zebu animals, respectively. In N'damas, O-acetyl and glycolyl groups were present in concentrations of 16.4 +/- 4.3 mg per dl and 12.8 +/- 2.9 mg per dl, respectively, whereas the corresponding values in Zebus were 2.8 +/- 5.0 mg per dl and 7.6 +/- 1.7 mg per dl, respectively. The differences between N'dama and Zebu cattle in surface sialic acids and in O-acetyl and glycolyl groups were significant (P < 0.01 to < 0.001). N'dama erythrocyte sialic acids had more O-acetyl than glycolyl groups while those of Zebus had less O-acetyl than glycolyl groups. These findings may be relevant to the trypanotolerance of N'dama cattle.

Erythrocyte membrane structural features that are critical for the lytic reaction of Spirographis spallanzani coelomic fluid hemolysin

1. Hemolytic activity of Spirographis spallanzani coelomic fluid depends on factor(s) strongly influenced by calcium but not by sulfhydril or disulfide reagents. 2. The lytic reaction was suppressed by low zinc ion concentrations but it was not influenced by the presence of proteinase inhibitors. 3. These data indicate that S. spallanzani hemolysin is a non-enzymatic, calcium-dependent, zincinhibitable factor that occurs naturally in the coelomic fluid. 4. In the absence of calcium, enzymatic desialization converted sheep erythrocytes into susceptible targets, suggesting the involvement of erythrocyte surface sialic acid. 5. However, the inhibitory effect of the sugar on anti-rabbit lysis was partially removed by addition of calcium. 6. Attempts to characterize membrane components that are critical for hemolysis were performed by inhibition experiments. 7. We found that saccharides, glycoproteins, mucosubstances as well as rabbit erythrocyte soluble tryptic fragments were ineffective in inhibiting hemolysis. 8. Sonicated dispersion of phosphatidyl choline, phosphatidyl glycerol, phosphatidyl ethanol, sphingomyelin and cholesterol did not influence the hemolytic reaction. 9. Rabbit erythrocyte extracted from membrane lipids (chloroform phase) did not modify the lytic activity against rabbit red blood cells. 10. Conversely, the methanol phase consistently reduced the lytic capacity of the fluid. 11. The heat-stable, trypsin-resistant inhibitory factor was most probably a small molecule, since dialysis removed the inhibitory effect.

Erythrocyte sialic acid in human sickle-cell disease

Membrane-bound erythrocyte surface sialic acid concentrations in sickle-cell human patients (SS) and in control patients with sickle-cell trait (AS) and normal genes (AA) were assayed. The erythrocyte sialic acid concentration was significantly ( P < 0·001) higher in sickle-cell patients than in non-sicklers and although the concentration was higher in AS than AA individuals the difference was not significant ( P > 0·05). The anaemic state of the SS patients was shown by a significantly ( P < 0·001) lower PCV than in non-sicklers. This finding is discussed in relation to membrane toughness and subsequent membrane loss leading to irreversible sickling of red cells in the deoxygenated state.

Erythrocyte surface sialic acid in Ndama and Zebu cattle

Erythrocyte surface sialic acid concentrations were measured in the trypano-tolerant Ndama and trypano-susceptible Zebu breeds of cattle. All animals were uninfected and had no records of previous exposure to infection by African pathogenic trypanosomes. Ndama adults had significantly ( P<0·001) higher erythrocyte surface sialic acid concentrations than Ndama calves. Ndama adults and calves had significantly ( P<0·001) higher erythrocyte surface sialic acid concentrations than Zebu adults. There were no significant differences between the packed cell volume (PCV), haemoglobin (Hb) concentrations and total leukocyte counts (WBC) of these breeds. The finding of much higher erythrocyte surface sialic acid concentrations (about 7-fold) in the Ndama than in the Zebu is discussed in relation to the induction of anaemia by trypanosome sialidase in both breeds and to how a relative trypano-tolerance may occur in the Ndama.

Erythrocyte membrane sialic acid in new-born infants.

Erythrocyte surface sialic acid was measured in 94 full-term new-born infants and in 20 premature infants of different ages, varying from 1 to 16 post-natal days. After the first 3 days of life, the amount of sialic acid, both per cell and per gramme of haemoglobin, was rapidly reduced to 70-80% of the initial value; these lower levels were maintained on the following days. The decrease observed on the 4th day may represent an expression of the mechanism by which a large amount of fetal red blood cells is eliminated from the circulation during the same period. Therefore, the relationship between sialic acid decrement and red cell sequestration exists also in fetal erythrocytes, and this may contribute to clarify the exact role of sialic acid in red cell survival time.

Variation in erythrocyte surface and free serum sialic acid concentrations during experimental Trypanosoma vivax infection in cattle

Erythrocyte surface and free serum sialic acid concentrations were determined during experimental Trypanosoma vivax infection in cattle. All infected calves developed mild trypanosomiasis, with significant decreases in mean packed cell volume occurring 15, 16, 20, 22 and 24 days after infection. The anaemia was preceded by significant decreases in mean erythrocyte surface sialic acid concentrations on days 7, 13 and 14, with yet another significant decrease on day 31 after infection. These decreases in erythrocyte surface sialic acid concentrations coincided with the parasitaemic waves. Free serum sialic acid concentration, however, showed an increase, though non-significantly, on day 8, which coincided with both a decrease in erythrocyte surface sialic acid and the initial parasitaemic wave. It is postulated that the early anaemia observed in infected animals may be attributable to the activities of the circulating trypanosomes which produce neuraminidase which, in turn, cleaves off surface sialic acid, thus rendering the erythrocyte more prone to phagocytosis by the recticuloendothelial system.

Determination of erythrocyte surface sialic acid residues by a new colorimetric method

The 3-methyl-2-benzothiazolone hydrazone method has been applied to the determination of erythrocyte membrane sialic acid residues. This method requires a mild oxidation of sialic acid which results in the formation of analogs. Their separation by chromatography, after labeling, allows the choice of the best conditions for this oxidation. The concomitant liberated formaldehyde is determined. This method requires no prior release of sialic acid as opposed to the periodate-thiobarbituric method of Warren (1959, J. Biol. Chem., 234, 1971–1975). These two methods have been compared.