The genetic basis and evolution of red blood cell sickling in deer

Poikilocytosis of Angora goats is associated with erythrocyte density and reticulocytosis

Angora goats in South Africa experience several syndromes that result in notable morbidity and mortality in juveniles and adults, but not kids. Insight into their causes is hampered by the lack of normal reference values for this breed, and the present study therefore aimed to characterise (1) differences in the haematology of healthy kids at birth and weaning, and (2) the haematology of apparently healthy yearlings. Selected variables were measured by blood smear analysis, and complete blood counts were performed using an ADVIA 2120i. Variables at 1, 11, and 20 weeks of age were compared using the Friedman test and associations between variables of yearlings were determined by correlation analysis. In kids, red blood cell count, mean corpuscular haemoglobin concentration (MCHC), and poikilocytosis increased over time, while mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) decreased. Yearlings displayed a lower MCHC, and higher haemoglobin distribution width than previously reported for goats, and these were positively correlated with poikilocytosis, as were reticulocyte counts. White cell counts of yearlings exceeded normal values previously reported for goats, with some individuals displaying remarkably high mature neutrophil counts. Changes in haemoglobin variant expression or cation and water fluxes are possible explanations for the findings in kids, while in yearlings, the associations between MCHC, HDW, poikilocytosis, and reticulocytosis suggest alterations in red cell hydration in adulthood that are associated with increased red cell turnover. These findings may prove informative in the further investigation of various clinical syndromes in this population.

Significance of two transmembrane ion gradients for human erythrocyte volume stabilization

Functional effectiveness of erythrocytes depends on their high deformability that allows them to pass through narrow tissue capillaries. The erythrocytes can deform easily due to discoid shape provided by the stabilization of an optimal cell volume at a given cell surface area. We used mathematical simulation to study the role of transport Na/K-ATPase and transmembrane Na+ and K+ gradients in human erythrocyte volume stabilization at non-selective increase in cell membrane permeability to cations. The model included Na/K-ATPase activated by intracellular Na+, Na+ and K+ transmembrane gradients, and took into account contribution of glycolytic metabolites and adenine nucleotides to cytoplasm osmotic pressure. We found that this model provides the best stabilization of the erythrocyte volume at non-selective increase in the permeability of the cell membrane, which can be caused by an oxidation of the membrane components or mechanical stress during circulation. The volume of the erythrocyte deviates from the optimal value by no more than 10% with a change in the non-selective permeability of the cell membrane to cations from 50 to 200% of the normal value. If only one transmembrane ion gradient is present (Na+), the cell loses the ability to stabilize volume and even small changes in membrane permeability cause dramatic changes in the cell volume. Our results reveal that the presence of two oppositely directed transmembrane ion gradients is fundamentally important for robust stabilization of cellular volume in human erythrocytes.

Peptide Biomarkers Discovery for Seven Species of Deer Antler Using LC-MS/MS and Label-Free Approach

Deer antler is a globally widely used precious natural medicine and the material of deer horn gelatin. However, identification of deer antler species based on traditional approaches are problematic because of their similarity in appearance and physical-chemical properties. In this study, we performed a comprehensive antler peptidome analysis using a label-free approach: nano LC-Orbitrap MS was applied to discover peptide biomarkers in deer adult beta-globin (HBB_A), and HPLC-Triple Quadrupole MS was used to verify their specificity. Nineteen peptide biomarkers were found, on which foundation a strategy for antlers and a strategy for antler mixtures such as flakes or powder are provided to identify seven species of deer antler including Eurasian elk (Alces alces), reindeer (Rangifer tarandus), white-tailed deer (Odocoileus viginianus), white-lipped deer (Przewalskium albirostris), fallow deer (Dama dama), sika deer (Cervus nippon), and red deer (Cervus elaphus) simultaneously. It is worth noting that our search found that the HBB_A gene of sika deer, red deer, and North American wapiti (Cervus canadensis) in China may have undergone severe genetic drifts.

Development of a Method to Detect Mycobacterium paratuberculosis in the Blood of Farmed Deer Using Actiphage® Rapid

Mycobacterium avium subsp paratuberculosis (MAP) is the causative agent of Johne's disease, which is an economically and clinically relevant pathogen for commercial deer production. The purpose of this study was to develop a method that could be used to rapidly detect MAP infection in deer using the Actiphage Rapid blood test. This test has previously been used to detect MAP in cattle blood following the purification of buffy coat using Ficoll gradients, however this method is quite laborious and costly. The purpose of this study was to develop a simpler method of blood preparation that was also compatible with deer blood and the Actiphage test. Initially differential lysis of RBCs using Ammonium Chloride-Potassium (ACK) blood lysis buffer was compared with the Ficoll gradient centrifugation method using cattle blood samples for compatibility with the Actiphage reagents, and it was found that the simpler ACK method did not have an impact on the Actiphage test reagents, producing an equivalent sensitivity for detection of low levels of MAP. When the two methods were compared using clinical blood samples from farmed deer, the ACK lysis method resulted in a cleaner sample. When a blinded test of 132 animals from 4 different production groups was carried out, the majority of the positive test results were found to be from animals in just one group, with a small number identified in a second group. The test results were found to be reproducible when a small set of positive animals were tested again 1 month after their initial testing. Finally a set of negative animals which had been previously screened using an ELISA test, all animals gave a negative Actiphage result. This study shows that this improved sample preparation method and Actiphage blood testing can be used to test blood samples from deer, and the full diagnostic potential of the method can now be evaluated.

An experimental erythrocyte rigidity index (Ri) and its correlations with Transcranial Doppler velocities (TAMMV), Gosling Pulsatility Index PI, hematocrit, hemoglobin concentration and red cell distribution width (RDW)

Brain artery velocities (Time-Averaged Maximum Mean Velocity, TAMMV) by Transcranial Doppler (TCD), hematocrit, hemoglobin, Red blood cell (RBC) Distribution Width (RDW) and RBC rigidity index (Ri), when reported together with their correlations, provide a accurate and useful diagnostic picture than blood viscosity measurements alone. Additionally, our study included a sixth parameter provided by TCD, the Gosling Pulsatility Index PI, which is an indicator of CBF (Cerebral Blood Flow) resistance. All these parameters are routine in Hematology except for values of Ri. The rigidity (Ri) of the RBC is the main rheological characteristic of the blood of Sickle Cell Anemia (SCA) patients and several pathologies. However, its quantification depends on many commercial and experimental techniques, none disseminated and predominant around the World. The difference in absorbance values of the blood, during the process of sedimentation in a microwell of a Microplate Reader, is a straightforward way of semi-quantifying the RBC rigidity Ri, since the fraction of irreversibly sickled red blood cells does not form rouleaux. Erythrocyte Rigidity Index (Ri) was calculated using initial absorbance A_initial (6 s) and final A_final (540 s), Ri = 1 / (Ai-Af). The Ri of 119 patients (2–17 y / o, M & F) SCA, SCC (Sickle Cell/hemoglobin C), SCD (Sickle Cell/hemoglobin D), Sβ0thal (Sickle Cell/hemoglobin Beta Zero Thalassemia) and 71 blood donors (20–65 y / o, M & F) were measured in our laboratory while the five parameters (TAMMV and PI by TCD, Hct, Hb and RDW) were obtained from medical records. The in vitro addition of hydroxyurea (HU, 50mg /dl, n = 51 patients, and n = 8 healthy donors) in the samples decreased the rouleaux adhesion strength of both donor and patients’ blood samples, leading to extraordinarily high Ri values. The correlation between the studied parameters was especially significant for the direct relationships between Ri, TAMMV, and PI.

Variation in the prion protein gene (PRNP) sequence of wild deer in Great Britain and mainland Europe

Susceptibility to prion diseases is largely determined by the sequence of the prion protein gene (PRNP), which encodes the prion protein (PrP). The recent emergence of chronic wasting disease (CWD) in Europe has highlighted the need to investigate PRNP gene diversity in European deer species, to better predict their susceptibility to CWD. Here we report a large genetic survey of six British deer species, including red (Cervus elaphus), sika (Cervus nippon), roe (Capreolus capreolus), fallow (Dama dama), muntjac (Muntiacus reevesii), and Chinese water deer (Hydropotes inermis), which establishes PRNP haplotype and genotype frequencies. Two smaller data sets from red deer in Norway and the Czech Republic are also included for comparison. Overall red deer show the most PRNP variation, with non-synonymous/coding polymorphisms at codons 98, 168, 226 and 247, which vary markedly in frequency between different regions. Polymorphisms P168S and I247L were only found in Scottish and Czech populations, respectively. T98A was found in all populations except Norway and the south of England. Significant regional differences in genotype frequencies were observed within both British and European red deer populations. Other deer species showed less variation, particularly roe and fallow deer, in which identical PRNP gene sequences were found in all individuals analysed. Based on comparison with PRNP sequences of North American cervids affected by CWD and limited experimental challenge data, these results suggest that a high proportion of wild deer in Great Britain may be susceptible to CWD.

"Sickling" in vertebrates: Animal studies vs. sickle cell disease

Before the description of sickled cells in humans, erythrocytes of normal deer were found to deform, or sickle in vitro. Sickling required oxygenation and alkalization; human erythrocytes sickle because their abnormal sickle hemoglobin (HbS) polymerizes following deoxygenation in vivo and in vitro. HbS and some deer hemoglobins polymerize because of specific amino acid contacts between hemoglobin beta-globin chains, although different amino acid residues form the contact points of the polymer. Hemoglobin precipitation is found in other vertebrates. Most often it is a benign in vitro phenomenon. Natural selection established the balanced polymorphism accounting for the high prevalence of HbS where malaria is endemic. A similar selective advantage for "sickling" animal hemoglobins is unproven. The mean corpuscular hemoglobin concentration is about 30 to 35 g/dL. Perhaps during in vitro studies of susceptible animal hemoglobins, minor changes in buffer pH, osmolality and the ligand state of the molecule increases mean cell hemoglobin concentration beyond its solubility limit allowing precipitation.

Infinite Assembly of Folded Proteins in Evolution, Disease, and Engineering

Mutations and changes in a protein's environment are well known for their potential to induce misfolding and aggregation, including amyloid formation. Alternatively, such perturbations can trigger new interactions that lead to the polymerization of folded proteins. In contrast to aggregation, this process does not require misfolding and, to highlight this difference, we refer to it as agglomeration. This term encompasses the amorphous assembly of folded proteins as well as the polymerization in one, two, or three dimensions. We stress the remarkable potential of symmetric homo-oligomers to agglomerate even by single surface point mutations, and we review the double-edged nature of this potential: how aberrant assemblies resulting from agglomeration can lead to disease, but also how agglomeration can serve in cellular adaptation and be exploited for the rational design of novel biomaterials.

Natural History of Plasmodium odocoilei Malaria Infection in Farmed White-Tailed Deer

Malaria parasites of the genus Plasmodium are known to infect a variety of vertebrate hosts, including ungulates (hoofed mammals). A recent study found that up to a quarter of white-tailed deer (Odocoileus virginianus) in North America are infected with the parasite Plasmodium odocoilei. In addition to occupying an important ecological niche, white-tailed deer are popular game animals and deer farming represents a rapidly growing industry. However, the effect of P. odocoilei infection in this ecologically and economically important ungulate species is unknown. Our work is significant because (i) we identified a high prevalence of P. odocoilei in farmed deer and (ii) we found evidence for both cleared and persistent infection, as well as an association with decreased survival of young fawns.

White-tailed deer (Odocoileus virginianus), an ecologically and economically important species, are the most widely distributed large animals in North America. A recent study indicated that up to 25% of all white-tailed deer may be infected with Plasmodium odocoilei, a malaria parasite belonging to the distinct clade of ungulate-infecting Plasmodium spp. Because the clinical impact of P. odocoilei on deer health and survival is unknown, we undertook a retrospective longitudinal study of farmed Floridian O. virginianus fawns. We found that a substantial proportion (21%) of fawns acquire malaria infection during the first 8 months of life. Some animals naturally clear P. odocoilei infection, while other animals remain persistently positive. Importantly, we found that animals that acquire malaria parasites very early in life have poor survival compared to animals that remain uninfected. Our report thus provides the first evidence of a clinically significant impact of malaria infection in young deer.

IMPORTANCE Malaria parasites of the genus Plasmodium are known to infect a variety of vertebrate hosts, including ungulates (hoofed mammals). A recent study found that up to a quarter of white-tailed deer (Odocoileus virginianus) in North America are infected with the parasite Plasmodium odocoilei. In addition to occupying an important ecological niche, white-tailed deer are popular game animals and deer farming represents a rapidly growing industry. However, the effect of P. odocoilei infection in this ecologically and economically important ungulate species is unknown. Our work is significant because (i) we identified a high prevalence of P. odocoilei in farmed deer and (ii) we found evidence for both cleared and persistent infection, as well as an association with decreased survival of young fawns.

Malaria in Farmed Ungulates: an Exciting New System for Comparative Parasitology

A wide array of vertebrates can serve as the intermediate hosts to malaria parasites (Apicomplexa: Haemosporida), such as birds, lizards, and several groups of mammals, including primates, bats, rodents, and ungulates. The latter group of hosts has not been intensively studied since early descriptions of a small set of taxa were published, but new reports of these parasites in both expected and new hosts have recently been published.

A wide array of vertebrates can serve as the intermediate hosts to malaria parasites (Apicomplexa: Haemosporida), such as birds, lizards, and several groups of mammals, including primates, bats, rodents, and ungulates. The latter group of hosts has not been intensively studied since early descriptions of a small set of taxa were published, but new reports of these parasites in both expected and new hosts have recently been published. A new paper reports the presence of Plasmodium odocoilei in farmed white-tailed deer in Florida, particularly in animals less than 1 year old, and provides evidence that the parasites may contribute to mortality in fawns. That paper opens new opportunities to study the malaria parasite-mammal interface in North America.