Rescue excavations recovered a skeleton that resurrect the contemporary dramatic history of Austria in the 17th century as troops besieged Vienna in the second Osmanic-Habsburg war. Unique for Central Europe is the evidence of a completely preserved camel skeleton uncovered in a large refuse pit. The male individual of slender stature indicates a few but characteristic pathological changes revealing not a beast of burden but probably a valuable riding animal. Anatomical and morphometrical analyses suggest a hybrid confirmed by the ancient DNA analyses resulting in the presence of a dromedary in the maternal and a Bactrian camel in the paternal line.
Allosuckling is a situation when a female nurses a non-filial offspring. It was described in various ungulate species; however for camels this is the first description of this behaviour. The aim of the study was to assess the occurrence of allosuckling in captive camels (Camelus bactrianus) and to test whether it can be explained as a ‘milk-theft’ (opportunistic behaviour of calves) or alternatively as an altruistic behaviour of females. During 2005 and 2007, nine camel females and ten calves in four zoological gardens in the Czech Republic were observed. In total, 373 sucking bouts were recorded, from which 32 were non-filial (the calf sucked from the non-maternal female). Allosuckling regularly appeared in captive camel herds. As predicted for the milk-theft explanation, the non-filial calves sucked more often in the lateral position and even did not suck in the antiparallel position at all. The non-filial calves preferably joined the filial calf when sucking but in five cases (15.6% of non-filial sucking bouts) the calves sucked from non-maternal dam without the presence of filial calf. We then expected the differences in terminations of sucking bouts by females but did not find any difference in sucking terminations for filial and non-filial calves. As the calves were getting older, the incidence of allosucking increased. This was probably because skills of the calf to outwit the non-maternal dam increased and/or the older calves might be more motivated for allosucking due to the weaning process. Finally, duration of a sucking bout was shorter with non-filial than filial calves. The results of the study support the hypothesis of ‘milk theft’, being mostly performed by calves behaving as opportunistic parasites, but we cannot reject certain level of altruism from the allonursing females or their increased degree of tolerance to non-filial calves.
- Proceedings of the National Academy of Sciences of the United States of America
- Published over 2 years ago
The four human coronaviruses (HCoVs) are globally endemic respiratory pathogens. The Middle East respiratory syndrome (MERS) coronavirus (CoV) is an emerging CoV with a known zoonotic source in dromedary camels. Little is known about the origins of endemic HCoVs. Studying these viruses' evolutionary history could provide important insight into CoV emergence. In tests of MERS-CoV-infected dromedaries, we found viruses related to an HCoV, known as HCoV-229E, in 5.6% of 1,033 animals. Human- and dromedary-derived viruses are each monophyletic, suggesting ecological isolation. One gene of dromedary viruses exists in two versions in camels, full length and deleted, whereas only the deleted version exists in humans. The deletion increased in size over a succession starting from camelid viruses via old human viruses to contemporary human viruses. Live isolates of dromedary 229E viruses were obtained and studied to assess human infection risks. The viruses used the human entry receptor aminopeptidase N and replicated in human hepatoma cells, suggesting a principal ability to cause human infections. However, inefficient replication in several mucosa-derived cell lines and airway epithelial cultures suggested lack of adaptation to the human host. Dromedary viruses were as sensitive to the human type I interferon response as HCoV-229E. Antibodies in human sera neutralized dromedary-derived viruses, suggesting population immunity against dromedary viruses. Although no current epidemic risk seems to emanate from these viruses, evolutionary inference suggests that the endemic human virus HCoV-229E may constitute a descendant of camelid-associated viruses. HCoV-229E evolution provides a scenario for MERS-CoV emergence.
We identified the near-full-genome sequence (29,908 nt, >99%) of Middle East respiratory syndrome coronavirus (MERS-CoV) from a nasal swab specimen from a dromedary camel in Egypt. We found that viruses genetically very similar to human MERS-CoV are infecting dromedaries beyond the Arabian Peninsula, where human MERS-CoV infections have not yet been detected.
Ovulation in mammals involves pulsatile release of GnRH from the hypothalamus into the hypophyseal portal system with subsequent release of LH from the anterior pituitary into systemic circulation. Elevated circulating concentrations of LH induce a cascade of events within the mature follicle, culminating in follicle rupture and evacuation. The broad classification of species as either spontaneous or induced ovulators is based on the type of stimulus responsible for eliciting GnRH release from the hypothalamus. In spontaneously ovulating species (e.g., human, sheep, cattle, horse, pigs), release of GnRH from the hypothalamus is triggered when, in the absence of progesterone, systemic estradiol concentrations exceed a threshold. In induced ovulators (e.g., rabbits, ferrets, cats, camelids), release of GnRH is contingent upon copulatory stimuli; hence, ovulation is not a regular cyclic event. Since a classic 1970 Peruvian study, dogma has maintained that physical stimulation of the genitalia during copulation is the primary trigger for inducing ovulation in alpacas and llamas. Exciting results of recent studies, however, provide direct evidence for the existence of an ovulation-inducing factor (OIF) in semen, and compel us to re-examine the mechanism of ovulation in both induced and spontaneous ovulators. Ovulation-inducing factor in seminal plasma is a potent stimulant of LH secretion, ovulation and luteal gland development, and acts via a systemic rather than a local route. OIF is a protein molecule that is resistant to heat and enzymatic digestion with proteinase K. It has a molecular mass of 14kDa, and may be part of a larger protein complex or pro-hormone. The effect of OIF is dose-related and evident at physiologically relevant doses (i.e., as little as 1/100th that present in the ejaculate), and is mediated, in whole or in part, at the level of the hypothalamus in vivo. The factor exists in the seminal plasma of every species in which it has been examined thus far, including Bactrian camels, alpacas, llamas, cattle, horses, pigs, and koalas. Seminal plasma OIF does not appear to be a phylogenetic vestige in spontaneous ovulators since it (1) induced ovulation in pre-pubertal mice, (2) altered ovarian follicular wave dynamics in cows, and (3) elicited LH release in vitro from primary pituitary cell cultures of rats, mice, guinea pigs, rabbits, llamas and cows.
Despite their production potential and ability to survive on marginal resources in extreme conditions, dromedaries have not been exploited as an important food source. Camels have not been specifically selected for milk production, and genetic improvement has been negligible. High individual variation in milk production both within the population and within breeds provides a good base for selection and genetic progress. In this paper, we discuss the possibilities and constraints of selective breeding for milk production in camels, and include a summary of the use of embryo transfer at the world’s first camel dairy farm. Embryo transfer is an integral part of the breeding strategy at the camel dairy farm because it increases selection intensity and decreases the generation interval. Using high milk-producing camels as donors and low producing camels as recipients, 146 embryos were recovered (6.1±1.0embryos/donor; range: 0-18). Embryos were transferred non-surgically into 111 recipients (83 single and 28 twin embryo transfers). Pregnancy rate at 21 days and 5 months was 55% (61/111) and 45% (50/111), respectively. Finally, a total of 46 recipients delivered a live calf. These results document the utility of embryo transfer using high milk producing dromedaries as donors.
Foregut digesta from five feral dromedary camels were inoculated into three different enrichment media: cotton thread, filter paper, and neutral detergent fiber. A total of 283 16S rRNA gene sequences were assigned to 33 operational taxonomic units by using 99% species-level identity. LIBSHUFF revealed significant differences in the community composition across all three libraries.
Camels are seasonal breeders, and their sexual behavior is influenced by environmental conditions, but the relationship between climatic factors and sexual behavior has been poorly described in the available literature. Nowadays, the male camel living habit is shifting towards captivity; thus, this study was carried out to evaluate the sexual behavior of housed male dromedary camel through female’s parades and to correlate it with climatic parameters. Four housed sires, reared for semen collection, and one dam were used and the trial lasted 8 weeks, considering the first week as control. Six days per week and during evenings, the female was brought near each males' boxes, while two observers filled a behavioral sampling ethogram and scored the male sexual behavior. After this parade, blood samples were taken from the female to evaluate the estradiol concentration. In addition, the following meteorological parameters were recorded, everyday, at 9:00 a.m. and 19:00 p.m.: pressure, wind, temperature, humidity, and H-index. The correlation between sexual behavioral score and female estradiol concentration and climate parameters was analyzed. All the behavioral parameters showed a significant upward trend; female estradiol concentration varied during the period and picked at week 5. Male sexual behavior was negatively correlated with morning H-index, wind, and temperature, and positively correlated with pressure and evening humidity, whereas it was not correlated with estrogen. In conclusion, female parade was a successful method to evaluate and stimulate the occurrence of housed male dromedary camel sexual activity that resulted to be negatively affected by hot temperature, warm wind, and lack of rain.
This study describes placental morphology and immunolocalization of the placental pregnancy associated glycoprotein-like family (PAGs) identified in two selected taxa of Old-World camels of the Camelidae family: Camelus dromedarius (Cd) and Camelus bactrianus (Cb). Placental tissues of Cd from days 140-293 post-coitum (dpc), term (404 dpc); and of Cb from term (440 dpc) were examined. Histological staining (hematoxylin/eosin and propidium iodine) revealed the development of the placental structure, while chorionic folding increased the feto-placental surface during the progress of pregnancy. The camelid placenta during early pregnancy is similar to the diffuse epitheliochorial type, and during later stages of pregnancy resembles the synepitheliochorial (cotyledonary) type. Placental expression of the PAGs was detected (Alexa 488 - green) within camelid trophectoderm cells (TRD - chorionic epithelium as outer layer of embryonic cells) among all placental cells with nuclei stained by propidium iodide (red). The PAGs, identified in both Camelidae taxa, were named CbPAGs and CdPAGs. Placental CbPAG and CdPAG expression is restricted to the TRD cells, which are differentially developed throughout gestation. Cross-reactivity of polyvalent anti-pPAG polyclonals with the CbPAGs and CdPAGs revealed high structural similarities of the PAG-like epitopes in pigs and camels. This is the first study identifying PAG expression in chorionic cells of the camel placenta.
The mechanism by which type I interferon-mediated antiviral response is mounted by hosts against invading pathogen is an intriguing one. Of late, an endoplasmic reticulum transmembrane protein encoded by a gene called stimulator of interferon genes (STING) is implicated in the innate signalling pathways and has been identified and cloned in few mammalian species including human, mouse and pig. In this article, we report the identification of STING from three different species of a highly conserved family of mammals - the camelids. cDNAs encoding the STING of Old World camels - dromedary camel (Camelus dromedarius) and bactrian camel (Camelus bactrianus) and a New World camel - llama (Llama glama) were amplified using conserved primers and RACE. The complete STING cDNA of dromedary camel is 2171 bp long with a 706-bp 5' untranslated regions (UTR), an 1137-bp open reading frame (ORF) and a 328-bp 3' UTR. Sequence and phylogenetic analysis of the ORF of STING from these three camelids indicate high level of similarity among camelids and conservation of critical amino acid residues across different species. Quantitative real-time PCR analysis revealed high levels of STING mRNA expression in blood, spleen, lymph node and lung. The identification of camelid STING will help in better understanding of the role of this molecule in the innate immunity of the camelids and other mammals.