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1.
Cesare Galli Irina Lagutina Roberto Duchi Silvia Colleoni Giovanna Lazzari 《Reproduction in domestic animals》2008,43(S2):331-337
The cloning of equids was achieved in 2003, several years after the birth of Dolly the sheep and also after the cloning of numerous other laboratory and farm animal species. The delay was because of the limited development in the horse of more classical-assisted reproductive techniques required for successful cloning, such as oocyte maturation and in vitro embryo production. When these technologies were developed, the application of cloning also became possible and cloned horse offspring were obtained. This review summarizes the main technical procedures that are required for cloning equids and the present status of this technique. The first step is competent oocyte maturation, this is followed by oocyte enucleation and reconstruction, using either zona-enclosed or zona-free oocytes, by efficient activation to allow high cleavage rates and finally by a suitable in vitro embryo culture technique. Cloning of the first equid, a mule, was achieved using an in vivo -matured oocytes and immediate transfer of the reconstructed embryo, i.e. at the one cell stage, to the recipient oviduct. In contrast, the first horse offspring was obtained using a complete in vitro procedure from oocyte maturation to embryo culture to the blastocyst stage, followed by non-surgical transfer. Later studies on equine cloning report high efficiency relative to that for other species. Cloned equid offspring reported to date appear to be normal and those that have reached puberty have been confirmed to be fertile. In summary, horse cloning is now a reproducible technique that offers the opportunity to preserve valuable genetics and notably to generate copies of castrated champions and therefore, offspring from those champions that would be impossible to obtain otherwise. 相似文献
2.
Adherence to various host cell lines of Mycoplasma bovis strains differing in pathogenic and cultural features 总被引：1，自引：0，他引：1
Thomas A Sachse K Dizier I Grajetzki C Farnir F Mainil JG Linden A 《Veterinary microbiology》2003,91(2-3):101-113
Mycoplasma bovis is known to be responsible for pneumonia and arthritis in calves, as well as mastitis in dairy cows. Despite clear evidence of its pathogenic potential, little is known about mechanisms of cytadherence and the molecular factors involved. The purpose of this work was to compare adherence rates of M. bovis field strains to different host cell lines and study the effects of cloning and sub-culturing M. bovis strains on their adherence properties. Eighteen metabolically labeled M. bovis strains isolated from different pathological backgrounds were examined in adherence trials using four different host cell lines, i.e. embryonic bovine lung (EBL), embryonic bovine trachea (EBTr), Madin Darby bovine kidney (MDBK) and rabbit kidney (RK) cells. Although large interstrain variations in adherence rates (3.4-19.1%) were measured they could not be correlated to the pathological background (pneumonia, arthritis or mastitis). Adherence rates to the fibroblast cell line (EBTr) were significantly lower than those to the three epithelial cell lines (EBL, MDBK and RK). The only non-pathogenic strain (221/89) exhibited lower adherence rates than three isolates from clinical mastitis. Interestingly, adherence rates were significantly reduced after in vitro passaging. In contrast, no effect of single cloning of strains on adherence was observed. There was no general correlation between expression of variable surface proteins (Vsps) as monitored by immunoblotting and adherence rates, although alterations in Vsp expression profiles were seen as a consequence of passaging. As there is probably a large number of adhesins, variable and non-variable, on the surface of M. bovis cells the issue is very complex, and the most active components have yet to be identified. 相似文献
3.
Successful mouse cloning of an outbred strain by trichostatin A treatment after somatic nuclear transfer 总被引：8，自引：0，他引：8
Kishigami S Bui HT Wakayama S Tokunaga K Van Thuan N Hikichi T Mizutani E Ohta H Suetsugu R Sata T Wakayama T 《The Journal of reproduction and development》2007,53(1):165-170
Although the somatic cloning technique has been used for numerous applications and basic research of reprogramming in various species, extremely low success rates have plagued this technique for a decade. Further in mice, the "clonable" strains have been limited to mainly hybrid F1 strains such as B6D2F1. Recently, we established a new efficient cloning technique using trichostatin A (TSA) which leads to a 2-5 fold increase in success rates for mouse cloning of B6D2F1 cumulus cells. To further test the validity of this TSA cloning technique, we tried to clone the adult ICR mouse, an outbred strain, which has never been directly cloned before. Only when TSA was used did we obtain both male and female cloned mice from cumulus and fibroblast cells of adult ICR mice with 4-5% success rates, which is comparable to 5-7% of B6D2F1. Thus, the TSA treatment is the first cloning technique to allow us to successfully clone outbred mice, demonstrating that this technique not only improves the success rates of cloning from hybrid strains, but also enables mouse cloning from normally "unclonable" strains. 相似文献
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5.
J C Baker 《The Veterinary quarterly》1991,13(1):47-59
Human respiratory syncytial virus (HRSV) is the major respiratory tract pathogen of infants and young children. Bovine respiratory syncytial virus (BRSV) is recognised as an important cause of respiratory tract disease in calves. Both of these viruses and their respective diseases share many similarities. Immunopathologic mechanisms have been proposed to be involved in the pathogenesis of respiratory syncytial virus (RSV) infections. This review examines the current understanding of the role of immunopathologic mechanisms in RSV infections. The role of vaccines in inducing hypersensitivity is also examined. Additionally, non-immunopathogenic mechanisms involved in RSV infections are discussed. 相似文献
6.
A variety of drugs may cause thrombocytopenia. Although it occurs more often than drug-induced anemia it is less well understood because techniques for studying drug-platelet-immune interactions have been unavailable until recently. The mechanisms by which drugs cause thrombocytopenia are varied. Bone marrow suppression or increased peripheral destruction of platelets could be involved. Nonimmunologic as well as immunologic mechanisms may also occur. These different mechanisms of drug-induced thrombocytopenia are reveiwed. Diagnostic methods and treatment are also summarized. 相似文献
7.
de la Torre-Escudero E Manzano-Román R Siles-Lucas M Pérez-Sánchez R Moyano JC Barrera I Oleaga A 《Veterinary parasitology》2012,184(1):25-36
Annexins belong to an evolutionarily conserved multigene family of proteins expressed throughout the animal and plant kingdoms. Although they are soluble cytosolic proteins that lack signal sequences, they have also been detected in extracellular fluids and have been associated with cell surface membranes, where they could be involved in anti-haemostatic and anti-inflammatory functions. Schistosome annexins have been identified on the parasite's tegument surface and excretory/secretory products, but their functions are still unknown. Here we report the cloning, sequencing, in silico analysis, and functional characterization of a Schistosoma bovis annexin. The predicted protein has typical annexin secondary and tertiary structures. Bioassays with the recombinant protein revealed that the protein is biologically active in vitro, showing fibrinolytic and anticoagulant properties. Finally, the expression of the native protein on the tegument surface of S. bovis schistosomula and adult worms is demonstrated, revealing the possibility of exposure to the host's immune system and thus offering a potential vaccine target for the control of schistosomiasis in ruminants. 相似文献
8.
Although glucocorticoids have been used successfully for the treatment of noninfectious inflammatory diseases of horses for more than 35 years, their use has been attended by a fear of the induction of laminitis. This paper reviews the evidence for this fear and the possible mechanisms whereby glucocorticoids could participate in laminitis induction. Although the association of laminitis with elevated serum cortisol in pituitary pars intermedia dysfunction suggests that chronic exposure to glucocorticoids may be part of laminitis pathogenesis, review of published reports and databases suggests that glucocorticoid‐induced laminitis is a relatively rare occurrence. However, several of the actions of glucocorticoids are similar to those known to be involved in laminitis pathogenesis. Glucocorticoid administration can induce insulin resistance, lead to vascular dysfunction that potentiates vasoconstriction, and interfere with keratinocyte proliferation and differentiation as well as matrix integrity, all mechanisms that could possibly induce laminitis. Drug formulation, dose and route of administration, and the systemic and hoof disease history of the horse must all be considered when assessing laminitis risk during glucocorticoid treatment. Generally, local glucocorticoid administration presents little risk as does systemic treatment of recurrent airway obstruction without concurrent disease. Caution should be used however in horses that are overweight and/or insulin resistant, or have had a recent bout of acute laminitis of alimentary or endotoxic origin. Overall, however, the risk of laminitis after glucocorticoid treatment, especially local use, is acceptable compared to the many benefits of these drugs. 相似文献
9.
Bovine respiratory syncytial virus (BRSV) belongs to the pneumovirus genus within the family Paramyxoviridae and is a major cause of respiratory disease in young calves. BRSV is enveloped and contains a negative sense, single-stranded RNA genome encoding 11 proteins. The virus replicates predominantly in ciliated respiratory epithelial cells but also in type II pneumocytes. It appears to cause little or no cytopathology in ciliated epithelial cell cultures in vitro, suggesting that much of the pathology is due to the host's response to virus infection. RSV infection induces an array of pro-inflammatory chemokines and cytokines that recruit neutrophils, macrophages and lymphocytes to the respiratory tract resulting in respiratory disease. Although the mechanisms responsible for induction of these chemokines and cytokines are unclear, studies on the closely related human (H)RSV suggest that activation of NF-kappaB via TLR4 and TLR3 signalling pathways is involved. An understanding of the mechanisms by which BRSV is able to establish infection and induce an inflammatory response has been facilitated by advances in reverse genetics, which have enabled manipulation of the virus genome. These studies have demonstrated an important role for the non-structural proteins in anti-interferon activity, a role for a virokinin, released during proteolytic cleavage of the fusion protein, in the inflammatory response and a role for the SH and the secreted form of the G protein in establishing pulmonary infection. Knowledge gained from these studies has also provided the opportunity to develop safe, stable, live attenuated virus vaccine candidates. 相似文献
10.
Benarafa C Cunningham FM Hamblin AS Horohov DW Collins ME 《Veterinary immunology and immunopathology》2000,76(3-4):283-298
We report the cloning of four equine CC chemokines, eotaxin, monocyte chemoattractant protein (MCP)-1, MCP-2 and MCP-4, which show high levels of identity with their respective homologous sequences in other species. Using a multiplex RT-PCR, we have studied the constitutive mRNA expression of these four CC chemokines in skin, lung, liver, spleen, jejunum, colon and kidney of normal adult horses and compared this data with the eosinophil counts in the same samples. We demonstrate that eotaxin mRNA is only expressed in jejunum and colon, where there are large numbers of eosinophils suggesting that eotaxin might be recruiting eosinophils in the normal digestive tract of the horse. MCP-1 and MCP-4 are expressed in all tissues whereas MCP-2 is only found in some samples of lung, spleen, liver and kidney. We also report the early induction (2h) of equine eotaxin and MCP-4, and the up-regulation of MCP-1 by interleukin-4 in dermal fibroblasts, suggesting these chemokines might be involved in equine skin allergic diseases. 相似文献
11.
Breeding sheep in New Zealand that are less reliant on anthelmintics to maintain health and productivity 总被引：1，自引：0，他引：1
Breeding sheep that are less reliant on the use of anthelmintics to maintain acceptable health and productivity is one of several options that may assist farmers to manage the growing anthelmintic-resistance problem in New Zealand and meet consumer demands to minimise drug usage in livestock. Although it has been known for many years that genetic factors contribute to the ability of sheep to cope with roundworm challenge, attempts to selectively breed for such factors have occurred only recently. Two host traits, 'resistance' and 'resilience', are thought to be involved in limiting the deleterious effects of roundworms on the health and productivity of sheep, and the associated need for treatment with anthelmintics. Over the last decade, considerable advances have been made in our understanding of the feasibility and implications of breeding for these traits under practical conditions. The experimental breeding lines developed as part of this research are now proving to be a valuable resource for further work directed at identifying genes and/or genetic markers associated with host resistance and understanding the mechanisms of host immunity to nematode parasites in ruminants. This review provides an up-to-date summary of the results of research in this field, with particular reference to dual-purpose sheep in New Zealand, and describes how this information is being applied in practical breeding programmes. 相似文献
12.
Alvarez-Pellitero P 《Veterinary immunology and immunopathology》2008,126(3-4):171-198
The increasing economic importance of fish parasitoses for aquaculture and fisheries has enhanced the interest in the defence mechanisms against these infections. Both innate and adaptive immune responses are mounted by fish to control parasite infections, and several mechanisms described for mammalian parasitoses have also been demonstrated in teleosts. Innate immune initiation relies on the recognition of pathogen-associated molecular patterns (PAMPs) by pathogen recognizing receptors (PRRs). A number of PRRs, mainly Toll-like receptors (TLRs), have been characterized in fish, and some molecules susceptible of functioning as PAMPs are known for some fish parasites. A lectin-carbohydrate interaction has also been described in some host fish-parasite systems, thus probably involving C-type lectin receptors. Inflammatory reactions involving cellular reactions, as phagocytosis and phagocyte activity (including oxidative mechanisms), as well as complement activity, are modulated by many fish parasites, including mainly ciliates, flagellates and myxozoans. Besides complement, a number of humoral immune factors (peroxidases, lysozyme, acute-phase proteins) are also implicated in the response to some parasites. Among adaptive responses, most data deal with the presence of B lymphocytes and the production of specific antibodies (Abs). Although an increasing number of T-cell markers have been described for teleosts, the specific characterization of those involved in their response is far from being obtained. Gene expression studies have demonstrated the involvement of other mediators of the innate and adaptive responses, i.e., cytokines [interleukins (IL-1, IL-8), tumor necrosis factor (TNF), interferon (IFN)], chemokines (CXC, CC), as well as several oxidative enzymes [inducible nitric oxide synthase (iNOS), cyclo-oxygenase 2 (COX-2)]. Information is scarcer for factors more directly linked to adaptive responses, such as major histocompatibility (MH) receptors, T cell receptors (TCRs) and IgM. Expression of some immune genes varied according to the phase of infection, and proinflammatory cytokines were mainly activated in the early stages. Gene expression was generally higher in the target tissues for some skin and gill parasites, as Ichthyophthirius multifiliis, Neoparamoeba spp. and Lepeophtheirus salmonis, thus confirming the relevance of mucosal immunity in these infections. The existence of protective responses has been demonstrated for several fish parasites, both in natural infections and in immunization studies. Most information on the mechanisms involved in protection deals with the production of specific Abs. Nevertheless, their levels are not always correlated to protection, and the precise involvement of immune mechanisms in the response is unknown in many cases. No commercial vaccine is currently available for piscine parasitoses, although experimental vaccines have been assayed against I. multifiliis, Cryptobia salmositica and scuticociliates. The known information points to the need for integrated studies of the mechanisms involved in protection, in order to choose the optimum antigen candidates, adjuvants and formulations. 相似文献
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14.
M. L. H. Campbell 《Equine Veterinary Education》2018,30(5):268-273
This paper assesses whether cloning horses is ethical by reviewing ethical arguments against cloning of nonequine species and determining whether they apply to horses, analysing ethical arguments about horse cloning which do not apply to noncompetitive species and considering the ethical dilemmas faced by veterinarians involved in horse cloning. The author concludes that concerns about the health and welfare of cloned horses render the technique ethically problematic and that the onus is on those providing commercial equine cloning services to collate data and provide a stronger evidence base for ethical decision‐making. 相似文献
15.
S.M. Singh L.J. Petherbridge L.P. Smith V.K. Nair 《Research in veterinary science》2010,89(1):140-145
A widely used vaccine against Marek’s disease (MD) in poultry is the virus SB-1, which is antigenically-related to the causative agent, Marek’s disease herpesvirus. We recently cloned the SB-1 genome as an infectious bacterial artificial chromosome, BAC, (pSB-1). The protective efficacies and replication kinetics of pSB-1 and the parent strain (SB-1) were compared in an experimental model of MD induced by a virulent strain, RB-1B. Although vaccine virus replication and shedding was lower for pSB-1 than for SB-1, both vaccines reduced replication and shedding of RB-1B, and were equally effective in protecting chickens against MD. With the cloning of pSB-1, we have now generated full length genomic clones of MD vaccine virus strains belonging to each of the three serotypes. Vaccine viruses derived from each of these clones demonstrated protective efficacies at levels similar to those produced by the respective parent viruses, demonstrating their suitability to be used as vaccine candidates. 相似文献
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17.
Prolactin: does it exert an up-modulation of the immune response in Trypanosoma cruzi-infected rats?
Filipin Mdel V Brazão V Santello FH Caetano LC Toldo MP do Prado JC 《Veterinary parasitology》2011,181(2-4):139-145
During the course of infection by Trypanosoma cruzi, the host immune system is involved in distinct, complex interactions with the endocrine system, and prolactin (PRL) is one of several hormones involved in immunoregulation. Although intensive studies attempting to understand the mechanisms that underlie Chagas' disease have been undertaken, there are still some pieces missing from this complex puzzle. Because data are scarce concerning the role of PRL involvement in Chagas' disease and taking into account the existence of crosstalk between neuroendocrine hormones and the immune system, the current study evaluates a possible up-regulation of the cellular immune response triggered by PRL in T. cruzi-infected rats and the role of PRL in reversing immunosuppression caused by the parasitic infection. The data shown herein demonstrate that PRL induces the proliferation of T lymphocytes, coupled with an activation of macrophages and the production of nitric oxide (NO), leading to a reduction in the number of blood trypomastigotes during the peak of parasitemia. During the acute phase of T. cruzi infection, an enhancement of both CD3+CD4+ and CD3+CD8+ T cell populations were observed in infected groups, with the highest numbers of these T cell subsets found in the infected group treated with PRL. Because NO is a signaling molecule involved in a number of cellular interactions with components of the immune system and the neuroendocrine system, PRL can be considered an alternative hormone able to up-regulate the host's immune system, consequently lowering the pathological effects of a T. cruzi infection. 相似文献
18.
P J Waller 《Veterinary parasitology》1987,25(2):177-191
Anthelmintic resistance has emerged as the most important problem confronting the successful control of nematode parasites of grazing animals. Although the significance of the problem varies between, and within, countries and farming enterprises, there is little likelihood that it will disappear of its own accord. On the contrary, it is reasonable to assume that it will increase if there is no change in traditional methods of parasite control. Although progress is being made in non-chemotherapeutic methods of control, these are unlikely to provide any practical alternatives in the short-term future. Nor can the pharmaceutical industry be expected to solve the problem because of the long period and the exceedingly high costs involved in bringing a completely new class of drug on to the market. The answer must lie in carefully husbanding the currently available anthelmintics, by providing farmers with programs which give good levels of parasite control and maintain high productivity in animals with fewer anthelmintic treatments. To be enthusiastically adopted by farmers, the programs require a commitment by both research and advisory workers. Such success can be achieved, as exemplified by the "Drenchplan" and "Wormkill" programs in Australia. It behoves workers in all countries which have a significant grazing livestock industry, not only those with an existing resistance problem, to consider how such schemes could be implemented. 相似文献
19.
Kokuho T Dang HV Yasue H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2012,74(3):367-372
Interleukin (IL)-12 and IL-23 play central roles in the regulation of distinct helper T-cell subsets, i.e. Th1 and Th17, respectively. Although IL-12 and IL-23 have been well studied in human and rodent systems, little is known about their significance in other animals, including livestock mammals such as cattle and pigs. In this study, we performed molecular cloning and genetic characterization of a small component of swine IL-23, i.e., IL-23p19; in addition, we identified and performed chromosomal assignment of the genes encoding its receptor (R) subunits IL-23Rα and IL-12Rβ1. These results provide genetic information about both swine IL-23/IL-23R and IL-12/IL-12R systems, which allows for better understanding of IL-12/IL-23 systems involved in pig immunity. 相似文献
20.
Varner G 《Animal welfare (South Mimms, England)》1999,8(4):407-420
This paper use the Missyplicity Project's detailed Code of Bioethics as a starting point for discussion of animal rights perspectives on cloning. Although funded by a couple in order to clone their pet dog, the project has more important collateral goals and forms part of a general line of research, that, if successful, promises enormous clinical benefits to humans. A particular type of animal rights perspective is described and used to evaluate this project. This perspective accepts a 'principle of axiological anthropocentrism' (PAA), according to which only human beings have certain interests, or a kind of value, which is of pre-eminent moral significance. The best-known animal rights views (those of Singer and Regan) are shown to be consistent with the PAA. This perspective also denies that potential characteristics qualify their possessors for the same type of moral respect as actualized characteristics. The balancing of potential benefits against risks to research subjects is discussed and it is concluded that, from the particular ethical perspective adopted in this paper, cloning research of this general type is not particularly problematic; and, given its stringent Code of Bioethics, only an abolitionist perspective could condemn the Missyplicity Project in particular. 相似文献