Mitochondrial control region and 12S rRNA variation in Przewalski's horse (Equus przewalskii)

Variation in the control region and the 12S rRNA gene of all surviving mitochondrial lineages of Przewalski's horse was investigated. Variation is low despite the present day population being descended from 13 individuals probably representing animals from three different regions of its range. Phylogenetic comparison of these sequences, with sequences for the domestic horse, does not resolve the ancestral status of either horse.     

FISH analysis comparing genome organization in the domestic horse (Equus caballus) to that of the Mongolian wild horse (E. przewalskii)

Przewalski's wild horse (E. przewalskii, EPR) has a diploid chromosome number of 2n = 66 while the domestic horse (E. caballus, ECA) has a diploid chromosome number of 2n = 64. Discussions about their phylogenetic relationship and taxonomic classification have hinged on comparisons of their skeletal morphology, protein and mitochondrial DNA similarities, their ability to produce fertile hybrid offspring, and on comparison of their chromosome morphology and banding patterns. Previous studies of GTG-banded karyotypes suggested that the chromosomes of both equids were homologous and the difference in chromosome number was due to a Robertsonian event involving two pairs of acrocentric chromosomes in EPR and one pair of metacentric chromosomes in ECA (ECA5). To determine which EPR chromosomes were homologous to ECA5 and to confirm the predicted chromosome homologies based on GTG banding, we constructed a comparative gene map between ECA and EPR by FISH mapping 46 domestic horse-derived BAC clones containing genes previously mapped to ECA chromosomes. The results indicated that all ECA and EPR chromosomes were homologous as predicted by GTG banding, but provide new information in that the EPR acrocentric chromosomes EPR23 and EPR24 were shown to be homologues of the ECA metacentric chromosome ECA5.     

Equine piroplasmoses at the reintroduction site of the Przewalski's horse (Equus ferus przewalskii) in Mongolia

Piroplasmosis has been identified as a possible cause of mortality in reintroduced Przewalski's horses (Equus ferus przewalskii) in the Dsungarian Gobi (Mongolia). A cross-sectional and a longitudinal study were conducted in a representative sample (n = 141) of the resident domestic horse population and in 23 Przewalski's horses to assess the prevalence of Theileria equi and Babesia caballi. Piroplasms were detected in blood by light microscopy in 6.7% (95% confidence interval [CI]: 3.6-12.2%) of the domestic horse samples. Antibody prevalence was 88.6% (95% CI: 82.4-92.9%) for T. equi and 75.2% (95% CI: 67.4-81.6%) for B. caballi. Antibody prevalence did not change over time, but antibody prevalence for both piroplasms were significantly lower in animals less than 1 yr of age. For both piroplasms, the prevalence of presumably maternal antibodies (falling titers) in foals was 100%. Only one of 16 foals seroconverted against T. equi during the study period, despite that piroplasms were found in two other individuals. The incidence density (ID) of T. equi in foals was therefore 0.0012 seroconversions per horse day (95% CI: 0.00029-0.0057). In contrast, yearlings had an ID of 0.0080 (95% CI: 0.0049-0.010) for T. equi and 0.0064 (95% CI: 0.0036-0.0093) for B. caballi, and in seven individuals piroplasms were detected. The seroprevalence of both piroplasms rose from 20% in spring to 100% in autumn. Comparison of domestic and Przewalski's horses resulted in a standardized prevalence ratio (SPR) of 0.98 (95% CI: 0.80-1.24, not significant) for B. caballi; in contrast, the prevalence of T. equi in Przewalski's horses was significantly lower than expected (SPR = 0.51, 95% CI: 0.50-0.64).     

圈养和放归成年雌性普氏野马(Equus przewalskii)夏季昼间的摄食行为

2005至2006年的6～8月间,在新疆普氏野马饲养与繁殖研究中心和卡拉麦里山有蹄类自然保护区,采用全事件取样法和目标动物取样法相结合,研究了圈养和放归成年雌性普氏野马夏季昼间的摄食行为.结果表明,两组个体在摄食行为类型上存在一定的差异,圈养个体普遍具有舔盐和食粪行为,而放归个体不存在此类行为.经独立样本t 检验,得出两组个体的摄食和站立行为的时间分配存在显著差异(P＜0.05),而站息、卧息、运动和其它行为差异不显著(P＞0.05),总体上,两组普氏野马的摄食行为所占时间最多.圈养个体昼间具有3个摄食高峰(8:00～10:00、13:00～15:00、19:30～20:00),与人工投食时间相一致,而放归个体摄食高峰并不明显,仅在13:00～15:00之间出现一个明显的摄食低谷,表现出自然的摄食节律及对放归地夏季自然条件的适应.     

Gene survival in the Asian wild horse (Equus przewalskii): I. Dependence of gene survival in the calgary breeding group pedigree

The joint probability distribution of the number of distinct (not identical by descent) genes from each founder of the Equus przewalskii population that survive in the five horses of the Calgary Zoological Gardens breeding group has been calculated. The dependence structure of this distribution is investigated, and informative marginal distributions are given, among them the distributions of the genetic contributions of each founder to the Calgary horses and the distribution of wild-type genes in these horses. The dependence pattern is found to be complex; there is no substitute for exact calculation of the full joint probability distribution of numbers of surviving genes. Probabilities of gene survival give a more complete summary of the genetic structure of a set of individuals than is provided by more routine measures such as heterozygosity or founder contributions. The feasibility of computing these probabilities for small groups of current individuals descended from few founders via long and complex pedigrees, provides a new approach to assessing such groups, and could be used also in selecting animals to form the founder stock of propagules for future reintroduction programs.     

Characterization of a novel variant of amino acid transport system asc in erythrocytes from Przewalski's horse (Equus przewalskii).

In thoroughbred horses, red blood cell amino acid transport activity is Na(+)-independent and controlled by three codominant genetic alleles (h, l, s), coding for high-affinity system asc1 (L-alanine apparent Km for influx at 37 degrees C congruent to 0.35 mM), low-affinity system asc2 (L-alanine Km congruent to 14 mM), and transport deficiency, respectively. The present study investigated amino acid transport mechanisms in red cells from four wild species: Przewalski's horse (Equus przewalskii), Hartmann's zebra (Zebra hartmannae), Grevy's zebra (Zebra grevyi), and onager (Equus hemonius). Red blood cell samples from different Przewalski's horses exhibited uniformly high rates of L-alanine uptake, mediated by a high-affinity asc1-type transport system. Mean apparent Km and Vmax values (+/- SE) for L-alanine influx at 37 degrees C in red cells from 10 individual animals were 0.373 +/- 0.068 mM and 2.27 +/- 0.11 mmol (L cells.h), respectively. As in thoroughbreds, the Przewalski's horse transporter interacted with dibasic as well as neutral amino acids. However, the Przewalski asc1 isoform transported L-lysine with a substantially (6.4-fold) higher apparent affinity than its thoroughbred counterpart (Km for influx 1.4 mM at 37 degrees C) and was also less prone to trans-stimulation effects. The novel high apparent affinity of the Przewalski's horse transporter for L-lysine provides additional key evidence of functional and possible structural similarities between asc and the classical Na(+)-dependent system ASC and between these systems and the Na(+)-independent dibasic amino acid transport system y+. Unlike Przewalski's horse, zebra red cells were polymorphic with respect to L-alanine transport activity, showing high-affinity or low-affinity saturable mechanisms of L-alanine uptake. Onager red cells transported this amino acid with intermediate affinity (apparent Km for influx 3.0 mM at 37 degrees C). Radiation inactivation analysis was used to estimate the target size of system asc in red cells from Przewalski's horse. The transporter's in situ apparent molecular weight was 158,000 +/- 2500 (SE).     

Gene survival in the Asian wild horse (Equus przewalskii): II. Gene survival in the whole population,in subgroups,and through history

In populations with a known pedigree, exact joint probability distributions of numbers of surviving of genes from each founder can now be calculated for moderately large complex pedigrees (1,000–2,000 individuals and much inbreeding). The usefulness of such calculations is shown by our analysis of gene survival in the Asian wild horse (Equus przewalskii), a species now extinet in the wild with a captive population with 1,516 individuals in the known pedigree (12 generations). We calculate the genetic diversity of subsets of the current population interesting to the North American Species Survival Plan, trace the loss of genetic diversity in this species through its history in captivity, and determine genetically important individuals in the North American population—those with relatively high probabilities of having unique copy genes (genes not found in any other living individual in North America).     

Immunocontraception of captive exotic species. I. Przewalski's horses (Equus przewalskii) and banteng (Bos javanicus)

A contraceptive vaccine made of porcine zonae pellucidae (PZP) was tested in three Przewalski's mares and five banteng cows. The vaccine antigen consisted of the complete family of glycoproteins of the porcine zona pellucida, including the sperm receptor ZP3. All mares and three of five banteng were inoculated with 2 or 3 i.m. injections of approximately 65 μg of antigen given over a 6 week period. Two other banteng received inoculations of only 35 μg of antigen on the same schedule. Two of the three mares and three of five banteng cows were pregnant at the time of inoculation. No new pregnancies, as a result of postinoculation breedings, occurred among either the mares 36 months after 65 μg antigen inoculations or among the banteng for 24 months after 65 μg inoculations. One postinoculation pregnancy resulted among the two banteng receiving only 35 μg of antigen. Differences in fertility between treated and control mares and between preinoculation and postinoculation reproductive performance of the banteng were significant (P < 0.05). Urinary ovarian steroid metabolites and behavioral observations indicated follicular development and ovulations were occurring among treated mares during the year following PZP inoculations. PZP immunization produced progressively elevated anti-PZP antibodies in both species, which provided contraceptive protection. PZP immunization appears to be an effective form of contraception in both species. © 1995 Wiley-Liss, Inc.     

Ciliates from the intestine of Yakut horse (Equus caballus)

Endobiotic ciliates of native Yakut horse are investigated. 57 ciliate species have been found. From 17 up to 43 species of ciliates have been revealed in each host specimen. The specimens of Alloiozona trizona Hsiung, 1930 and Triadinium caudatum Fiorentini, 1890 were present in 100 % of the horses. The endemic genus and species of allantosomides, Strelkowella urunbasiensis Kornilova, 2004, has been found in 11 horses. Allantoxena japonensis (Imai, 1979) and Cycloposthium ishikawai Gassovsky, 1919 being recorded previously in Japan only were found for the first time in Russia. The species Cycloposthium ponomarevi Kornilova, 2001 peculiar to the Turkmenistan koulan has been found in the Yakut horses.     

Distribution of iron in pig placenta (Sus scrofa dom. L.)

Iron distribution was studied in pig placentae between 21 day till the end of pregnancy (113) with the use of histochemical and cytochemical methods and X-ray microanalysis. Iron content was measured in fetal and maternal part of the placenta with chemical methods. Iron presence was confirmed in maternal and fetal erythrocytes, cells and secretion of uterine glands and trace amount in trophoblast lining regular areolae. No significant differences were found in iron content in fetal and maternal part of the placenta throughout the entire studied period. With the applied histochemical method of iron determination according to Perls, potassium ferrocyanide also adsorbs in sites where mucopolysaccharides are present, in which iron presence has not been detected with the use of X-ray microanalysis.     

Breathing strategy of the adult horse (Equus caballus) at rest

To investigate the mechanism underlying the polyphasic airflow pattern of the equine species, we recorded airflow, tidal volum, rib cage and abdominal motion, and the sequence of activation of the diaphragm, intercostal, and abdominal muscles during quiet breathing in nine adult horses standing at rest. In addition, esophageal, abdominal, and transdiaphragmatic pressures were simultaneously recorded using balloon-tipped catheters. Analysis of tidal flow-volume loops showed that, unlike humans, the horse at rest breathes around, rather than from, the relaxed volume of the respiratory system (Vrx). Analysis of the pattern of electromyographic activities and changes in generated pressures during the breathing cycle indicate that the first part of expiration is passive, as in humans, with deflation toward Vrx, but subsequent abdominal activity is responsible for a second phase of expiration: active deflation to below Vrx. From this end-expiratory volume, passive inflation occurs toward Vrx, followed by a second phase of inspiration: active inflation to above Vrx, brought about by inspiratory muscle contraction. Under these conditions the abdominal muscles appear to share the principal pumping duties with the diaphragm. Adoption of this breathing strategy by the horse may relate to its peculiar thoracoabdominal anatomic arrangement and to its very low passive chest wall compliance. We conclude that there is a passive and active phase to both inspiration and expiration due to the coordinated action of the respiratory pump muscles responsible for the resting adult horse's biphasic inspiratory and expiratory airflow pattern. This unique breathing pattern perhaps represents a strategy of minimizing the high elastic work of breathing in this species, at least at resting breathing frequencies.     

Water consumption and watering behavior of Przewalski horses (Equus ferus przewalskii) in a semireserve

Water consumption by 12 female Przewalski horses was automatically measured in a semireserve for 17 months. Average daily consumption on a yearly basis was between 2.4 and 8.3 liters, but significant individual variation in water consumption and drinking frequency was recorded throughout the observation period. Individual differences were more clearly detectable during periods of hot and dry weather. Individuals with high water demands initiated herd movements toward watering places independent of their social rank. Discussed as possible reasons for individual differences in water demand are: acquired preferences, distinct food selection, and genetically determined physiological differences. Watering behavior should not be regarded as an important factor only in re-introduction projects, but also with respect to animal welfare in general. Zoo Biol 17:181–192, 1998. © 1998 Wiley-Liss, Inc.     

Histochemistry of the duodenal glands of the cat and horse.

The duodenal glands of cat and horse were studied using PAS, Alcian blue, dialysed iron, aldehyde fuchsin-Alcian blue and high iron diamine stains. It was found that the duodenal glands of the horse reacted positively to Alcian blue, dialysed iron stains and also took the Alcian blue stain in the combined aldehyde fuchsin-Alcian blue and high iron diamine-Alcian blue stains. Those of the cat gave negative results. These results suggest the presence of acidic groups in the mucosubstances secreted by the horse's duodenal glands. A suggestion is put forward on the strength of the high iron diamine-Alcian blue combined stains that the acidity is due to the presence of carboxyl groups. It is suggested that the acidity may be significant in either cellulose metabolism or the digestion of the bacterial microflora from the stomach of herbivores.     

Aspects of the Water Relations of Ileostylus micranthus (Hook. f.) Tieghem, a New Zealand Mistletoe

Leaf water potentials in the mistletoe, Ileostylus micranthusgrowing outdoors decreased rapidly during the early part ofthe day but remained relatively steady in the early afternoondespite increases in atmospheric vapour pressure deficit (vpd).Minimum water potentials of the mistletoe were relatively constant.They were held at values lower than those of hosts when thelatter maintained high water potentials but approached or evenexceeded those of hosts when they developed low water potentials.In contrast, cut shoots of Ileostylus usually maintained higherwater contents and leaf water potentials than those of its hostswhen both were desiccated separately in the laboratory. Pressure-volumeanalyses indicated that Ileostylus had lower water potentialat full turgor, a lower water potential but higher relativewater content at turgor loss, and a higher bulk modulus of elasticitythan the following four hosts: the native Kunzea ericoides andCoprosmapropinqua, and the introduced Ribes sanguineum and Teline monspessulana.Water potential at turgor loss (_tlp) was strongly correlatedwith the minimum field water potential of both mistletoes andhosts. When _tlpof mistletoe and host is similar (as on Kunzeaand Ribes) field water potentials are also similar, but when_tlpis lower in the mistletoe (as on Coprosma and Teline), thefield water potential of the mistletoe is lower than that ofits host. Consequently, I. micranthus is likely to be more frequenton hosts that maintain high field water potentials than on hoststhat develop low water potentials. Copyright 1999 Annals ofBotany Company Water relations, water potential, osmotic potential, pressure-volume, Ileostylus micranthus , mistletoe, New Zealand.     

Chemical, biological and immunological properties of pituitary gonadotropins from the donkey (Equus asinus): comparison with the horse (Equus caballus)

Donkey gonadotropins (donkey luteinizing hormone, dLH; donkey follicle-stimulating hormone, dFSH) have been isolated in purified form from 191 donkey pituitaries using essentially the same procedures previously employed for the purification of equine gonadotropins. Chemically, dLH and dFSH were observed to be similar to equine LH (eLH) and FSH (eFSH) in fractionation behavior and glycoprotein nature. Two forms of the dFSH molecule were observed, as is the case for eFSH. Donkey LH had significantly less total carbohydrate (13.5%) and sialic acid (1.9%) than eLH (26.7% and 5.8%, respectively). Carbohydrate (17-21%) and sialic acid (2.4%) content of the two dFSH preparations closely resembled that of eFSH. A slightly higher tyrosine content in the donkey gonadotropins was noted in a comparison of amino acid compositions. Immunologically, in a heterologous FSH radioimmunoassay (RIA), dFSH preparations were equal to or twice as active as eFSH preparations. However, in homologous RIAs for equine chorionic gonadotropin (eCG), eFSH and eLH, both the dLH and dFSH preparations were considerably less active than the equine gonadotropins, and their inhibition curves were all nonparallel. Biologically, in the Steelman-Pohley assay both dFSH preparations were equipotent and as potent as eFSH (approximately 40 times NIH-FSH-S12). In the Sertoli cell assay for cAMP (FSH assay) and the Leydig cell assay for testosterone (LH assay), both dFSH and dLH were 2- or 6-fold more active than eFSH and eLH, respectively. In rat and equine testis FSH homologous radioreceptor assays, dFSH preparations were as active and up to 6-fold more active than eFSH. In contrast, dLH was 10-fold less active than eLH in the equine LH homologous radioreceptor assay. Unlike eLH, dLH was found to possess little intrinsic FSH activity or FSH inhibitory activity, and the small amount of FSH activity observed was most likely due to FSH contamination. Therefore, eLH behaves much like eCG (pregnant mare's serum gonadotropin, PMSG) which also possesses both LH and FSH activity. In contrast, dLH behaves more like donkey chorionic gonadotropin (dCG) which possesses only a low degree of FSH activity.     

Sequence of horse (Equus caballus) apoA-II. Another example of a dimer forming apolipoprotein

Apolipoprotein A-II, the second major apolipoprotein of human HDL, also has been observed in a variety of mammals; however, it is either present in trace amounts or absent in other mammals. In humans and chimpanzee, and probably in other great apes, apoA-II with a cysteine at residue 6 is able to form a homodimer. In other primates as well as other mammals, apoA-II, lacking a cysteine residue, is monomeric. However, horse HDL has been reported to contain dimeric apoA-II that following reduction forms monomers. In this report, we extend these observations by reporting on the first complete sequence for a horse apolipoprotein and by demonstrating that horse apoA-II also contains a cysteine residue at position 6. Both the intact protein and its enzymatic fragments were analyzed by chemical sequence analysis and time-of-flight MALDI-MS (matrix assisted laser desorption ionization mass spectrometry). We also obtained molecular mass data on dimeric and monomeric apoA-II using electrospray-ionization mass spectrometry (ESI-MS). The data are compared with other mammalian sequences of apoA-II and are discussed in terms of resulting similarities and variations in the primary sequences.