Evaluation of the efficiency of TaqMan duplex real-time PCR assay for non-invasive pre-natal assessment of foetal sex in equine

Accurate diagnosis of foetal sex in pregnant mare is helpful for many breeders, both for private or commercial purposes. In this study, in order to pre-natal foetal sexing in equine, we used TaqMan duplex real-time PCR to detect the specific regions of SRY and TSPY genes on extracted cell-free foetal DNA from maternal blood. Peripheral blood samples from 50 pregnant Arabian mares with singleton foetuses were collected. Cell-free foetal DNA was extracted from maternal plasma, and duplex real-time PCR assays were performed with TaqMan probes and primers. Amplification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene was used as control of DNA extraction procedure. From the 50 sampled mares, 28 cases had female and 22 mares had male foetuses. The final results for 46 samples were conclusive, and from them, 43 cases were predicted correctly. Sensitivity, specificity and accuracy of the test were 90.48%, 96% and 93.48%, respectively. In conclusion, a TaqMan duplex real-time PCR was set up to pre-natal detection of foetal sex in equine. The method was fast and decreased the false-positive and false-negative results. The technique can be used as a routine procedure in farms by collecting only a blood sample.     

Effect of Pregnancy and Foetal Number on Diameter of Corpus Luteum,Maternal Progesterone Concentration and Oxidant/Antioxidant Balance in Ewes

The aim of this study was to determine the changes in diameter of corpus luteum (CL), maternal progesterone (P) concentration, lipid peroxidation and non‐enzymatic antioxidant levels along with enzymatic antioxidant activities in pregnant ewes bearing single and twin foetuses. The ewes were selected from healthy animals that were brought to the abattoir for slaughtering. The ewes were divided into three groups: Group 1 (non‐pregnant, non‐oestrous, n = 30), Group 2 (pregnant bearing a single foetus, n = 30) and Group 3 (pregnant bearing twin foetuses, n = 12) after they were slaughtered. Pregnant ewes were in the first half of the pregnancy. The diameter of CL and P concentration of pregnant ewes bearing a single foetus or twin foetuses were found higher than that found in non‐pregnant ewes. Similarly, the P concentration of pregnant ewes bearing twin foetuses was higher than that found in pregnant ewes bearing a single foetus. Malondialdehyde (MDA) level in pregnant ewes bearing twin foetuses was higher than that found in both non‐pregnant and pregnant ewes bearing a single foetus. The serum glutathione (GSH) level and glutathione‐peroxidase (GSH‐Px) activity of pregnant ewes bearing twin foetuses were found lower than that found in non‐pregnant ewes. Additionally, the GSH‐Px activity of pregnant ewes bearing twin foetuses was found lower than that found in pregnant ewes bearing a single foetus. No significant difference was found between pregnant ewes bearing female and male foetus with respect to diameter of CL, P concentration and oxidative stress parameters. There were significant positive correlations between foetal number (0, 1, 2) and diameter of CL, P concentration, MDA level, and between P concentration and diameter of CL, MDA level. However, significant negative correlations were found between foetal number (0, 1, 2) and GSH level, GSH‐Px activity, and between P concentration and GSH‐Px activity. In conclusion, the diameter of CL enlarges, P production increases and oxidant/antioxidant balance impairs because of the gestation stress in ewes during pregnancy.     

A Polymerase Chain Reaction for Detection of Equine Herpesvirus‐1 in Routine Diagnostic Submissions of Tissues from Aborted Foetuses

Equine herpesvirus 1 (EHV‐1) is the causative agent of abortion, perinatal foal mortality, neurological and acute respiratory diseases in horses. Conventional laboratory diagnosis involving viral isolation from aborted foetuses is laborious and lengthy and requires processing of samples within 24 h of collection, which is problematic for samples that come from long distances. The aim of this study was to develop a polymerase chain reaction (PCR) assay useful in Argentina to detect DNA sequences of EHV‐1 in different tissues from aborted equine foetuses with variable quality of preservation and without the use of conventional DNA fenolic extraction. Several DNA extraction protocols and primers were evaluated. The amplification method was standardized and its specificity was analysed using 38 foetal samples of variable quality of preservation. Of the 38 different foetal tissues, nine livers, six spleens and two lungs in good preservation and eight livers, one spleen and four lungs in a poor state of preservation were positive for PCR. EHV‐1 was recovered only from the nine livers, five spleens and two lungs in good preservation. No virus was isolated from the samples that were poorly preserved. Viral isolation was confirmed by cytopathic effect and indirect immunofluorescence. The specificity of the PCR results was confirmed by the restriction endonuclease digestion of PCR products and hybridization.     

Pregnancy diagnosis in pigs: A field study comparing linear‐array real‐time ultrasound scanning and amplitude depth analysis

Summary

Between days 24 and 32 after mating/insemination, 881 pigs (785 pregnant and 96 not‐pregnant) were tested for pregnancy on a commercial farm with a linear‐array real‐time ultrasound scanner. 5–7 Days later, 785 of these animals (708 pregnant and 77 not‐pregnant) were tested again with A‐mode equipment by farm employees. Confirmation of pregnancy was based on recorded farrowings or abortions: confirmation of non‐pregnancy was based on return to oestrus and rebreeding, recorded non‐farrowing, or inspection of the uterus of culled animals at the slaughterhouse. From the number of correct positive (a), incorrect positive (b), correct negative (c) and incorrect negative (d) diagnoses, a sensitivity (a/a + d) of 100% versus 97.5%, a specificity (c/c + b) of 90.6 versus 55.8%, a positive predictive value (a:a + b) of 98.9% versus 95.3% and a negative predictive value (c:c + d) of 100% versus 70.5% were calculated for the real‐time ultrasound technique versus A‐mode technique.

It was concluded that real‐time ultrasound scanning provides a very accurate technique for pregnancy diagnosis in pigs, enabling immediate decision making on treatment or culling of animals diagnosed as non‐pregnant.     

Experimental Infection of Cows with Bovine Viral Diarrhoea Virus in Early Pregnancy – Findings in Serum and Foetal Fluids

Nineteen pregnant cows were experimentally infected with bovine viral diarrhoea virus (BVDV) between day 74 and 81 of pregnancy. All cows became infected and developed serum antibodies. Sixteen of the cows delivered persistently infected (PI) offspring, whereas the remaining three gave birth to calves with detectable serum antibodies and free from BVDV. The 16 cows with PI foetuses developed higher levels of antibodies in serum during pregnancy than did their three peers carrying non‐PI calves. Multivariate analysis showed that the antibody levels in these two groups of cows were significantly different from day 135 of pregnancy. Foetal fluid was successfully collected from 18 of the 19 infected cows and from five uninfected control cows between 10 and 24 days before delivery by use of a percutaneous, blind puncture technique. No negative effects were observed in the cows or their offspring. BVDV was isolated and detected with an immunoperoxidase test in foetal fluid from 13 of the 16 cows carrying PI foetuses, and from 15 of the cows when a quantitative fluorescent polymerase chain reaction (PCR) technique was used. The negative sample in the PCR assay was positive for BVDV antibodies. The number of viral copies per microlitre in foetal fluids varied between 103 and 1080 in the positive samples. All samples taken from the cows carrying non‐PI foetuses were negative for BVDV in both assays. In this experiment, examination of either serum or foetal fluids could identify the cows carrying a PI foetus. Examination of serum for BVDV antibodies was a reliable indicator of a PI foetus if the serum was collected during the last 2 months of pregnancy. For examination of foetal fluids, both viral and serological analyses should be performed. For viral analysis, PCR should be the test of choice. High levels of BVDV antibodies in conjunction with a negative result in the PCR may be indicative of a false‐negative virus result. Further experience with the method of collection of foetal fluids is necessary for evaluation of its safety. Investigation of pregnant cows in order to discover a PI offspring before it is born could be a useful tool in control and eradication of BVDV.     

A polymerase chain reaction for detection of equine herpesvirus-1 in routine diagnostic submissions of tissues from aborted foetuses

Equine herpesvirus 1 (EHV-1) is the causative agent of abortion, perinatal foal mortality, neurological and acute respiratory diseases in horses. Conventional laboratory diagnosis involving viral isolation from aborted foetuses is laborious and lengthy and requires processing of samples within 24 h of collection, which is problematic for samples that come from long distances. The aim of this study was to develop a polymerase chain reaction (PCR) assay useful in Argentina to detect DNA sequences of EHV-1 in different tissues from aborted equine foetuses with variable quality of preservation and without the use of conventional DNA fenolic extraction. Several DNA extraction protocols and primers were evaluated. The amplification method was standardized and its specificity was analysed using 38 foetal samples of variable quality of preservation. Of the 38 different foetal tissues, nine livers, six spleens and two lungs in good preservation and eight livers, one spleen and four lungs in a poor state of preservation were positive for PCR. EHV-1 was recovered only from the nine livers, five spleens and two lungs in good preservation. No virus was isolated from the samples that were poorly preserved. Viral isolation was confirmed by cytopathic effect and indirect immunofluorescence. The specificity of the PCR results was confirmed by the restriction endonuclease digestion of PCR products and hybridization.     

Morphometric study of the porcine placental vascularization

The early development in mammals is characterized by the contribution of nutrients from the maternal tissues through the placenta, which is in apposition with foetal membranes and the endometrium, allowing the physiological interchange between the embryos/foetuses and the mother. The aim of this work was to study the number of placental blood vessels and their vascular area through morphometric analyses and the haemotrophic diffusion distance in porcine placental tissues from early gestations, intermediates gestations, advanced gestations and term gestations. For those purposes, morphometric measurements, blood vessel quantification, high‐resolution light microscopy and transmission electron microscopy were performed. The implementation of the high‐resolution light microscopy allowed studying the placental vascular and tissue histoarchitecture with higher definition and resolution than using a conventional light microscopy. We highlight the close location of the subepithelial capillaries to the maternal/foetal interface as pregnancy progresses. We found statistically significant evidence to state that the area of blood vessels is dependent on the gestation period. In advanced gestations, the presence of numerous small blood vessels and its near location to foetal/maternal interface agree with the great remodelling reported in our previous studies. In conclusion, in gilts, given the type of non‐invasive epithelial placentation, the new blood vessels generation and of haemotrophic diffusion distance reduction, determined in this report, assure the maternal/foetal haemotrophic exchange efficiency during gestation.     

Validation and application of real-time polymerase chain reaction assays for representative rumen bacteria

Real‐time polymerase chain reaction (PCR) assays for 11 representative rumen bacterial species were validated. The sensitivity was tested by using the serially diluted target 16S rDNA from respective bacterial species. The recovery of the target DNA and the assay reproducibility were determined using DNA from rumen fluid spiked with different quantities of the target. Minimum detection levels for the target were 10–100 copies in pure culture. The recovery of the added target ranged from 82.4 to 116.6%. The intra‐ and inter‐assay variations of each assay were <9.4 and <12.6%, respectively. Therefore, the real‐time PCR assays evaluated in the present study are considered to be sufficiently reliable for monitoring all 11 bacterial species in the rumen. The assays were then applied to the monitoring of the bacterial species attached to ruminally incubated rice straw. Among the monitored fibrolytic species, Fibrobacter succinogenes was found to be the most dominant, accounting for 2.61% of total bacteria after 24 h incubation. Selenomonas ruminantium and Streptococcus bovis, non‐fibrolytics, were detected on the rice straw at 8.96% and 1.16% of total bacteria, respectively. Such high levels of non‐fibrolytics on the plant fiber suggest a synergistic relationship between fibrolytics and non‐fibrolytics.     

Effective use of the TSPY gene‐specific copy number in determining fetal DNA in the maternal blood of cynomolgus monkeys

Since the available concentration of single‐copy fetal genes in maternal blood DNA is sometimes lower than detection limits by PCR methods, the development of specific and quantitative PCR detection methods for fetal DNA in maternal blood is anticipated, which may broaden the methods that can be used to monitor pregnancy. We used the TaqMan qPCR amplification for DYS14 multi‐copy sequence and the SRY gene in maternal blood plasma (cell‐free DNA) and fractional precipitated blood cells (cellular DNA) from individual cynomolgus monkeys at 22 weeks of pregnancy. The availability of cell‐free fetal DNA was higher in maternal blood plasma than that of cellular DNA from fractional precipitated blood cells. There was a significantly higher (P < 0.001) mean copy number of fetal male DYS14 from maternal plasma (4.4 × 10⁴ copies/mL) than that of detected fetal cellular DNA from fractional blood cell pellets. The sensitivity of the DYS14 PCR assay was found to be higher than that of the SRY assay for the detection of fetal DNA when its presence was at a minimum. The DYS14 assay is an improved method for quantifying male fetal DNA in circulating maternal blood in the primate model.     

Analysis and Validation of the Differentially Expressed ENO1 in the Maternal Placenta of Cow with Retained Foetal Membrane

The paper aimed to analyze and validate the function of differentially expressed ENO1 in the cow with retained foetal membrane.In our research,we chose three healthy Holstein dairy cows and three Holstein dairy cows with retained foetal membrane of similar age,foetal times,weight and milk yield and divided them into two groups.The total protein of maternal placenta was extracted in the control and retained foetal membrane of cow.The differential expression of proteins were found out by the 2-DIGE,and the differential expression of ENO1 was validated by the Western blotting and Real-time quantitative PCR.The results showed that ENO1 was significant expression and large multiple in the two groups,and it was significant increased expression in the retained foetal membrane of cow after Western blotting and Real-time quantitative PCR (P=0.015<0.05;P=0.001<0.01).The ENO1 participated in the energy homeostasis,immune and fibrinolysis process which related to the retained foetal membrane of cow.It suggested that ENO1 was likely connected with the retained foetal membrane.     

胎衣不下奶牛母体胎盘α-烯醇化酶异常表达分析及验证

试验通过对胎衣不下奶牛母体胎盘组织中差异α-烯醇化酶(enolase,ENO1)的分析验证,探讨ENO1在胎衣不下中的作用。本研究选取了年龄、胎次、体重和泌乳量均相近的产后胎衣不下和产后胎衣正常排出奶牛各3头,分为两组,提取了胎衣不下组与胎衣正常排出组母体胎盘组织中的总蛋白,采用双向凝胶电泳的方法筛选出差异蛋白,并利用Western blotting及实时荧光定量PCR的方法对其中差异表达量大的ENO1进行验证。结果发现,胎衣不下组和胎衣正常组母体胎盘组织中ENO1差异表达量大且倍数较大,Western blotting及实时荧光定量PCR验证发现ENO1在胎衣不下奶牛母体胎盘中的表达量升高,t检验结果分别为P=0.015<0.05,差异显著;P=0.001<0.01,差异极显著。该基因参与机体的能量调节、免疫和纤溶等过程,而这些过程与奶牛胎衣不下密切相关,提示ENO1可能参与该病的发生发展。     

An optimised protocol for molecular identification of Eimeria from chickens

Molecular approaches supporting identification of Eimeria parasites infecting chickens have been available for more than 20 years, although they have largely failed to replace traditional measures such as microscopy and pathology. Limitations of microscopy-led diagnostics, including a requirement for specialist parasitological expertise and low sample throughput, are yet to be outweighed by the difficulties associated with accessing genomic DNA from environmental Eimeria samples. A key step towards the use of Eimeria species-specific PCR as a sensitive and reproducible discriminatory tool for use in the field is the production of a standardised protocol that includes sample collection and DNA template preparation, as well as primer selection from the numerous PCR assays now published. Such a protocol will facilitate development of valuable epidemiological datasets which may be easily compared between studies and laboratories. The outcome of an optimisation process undertaken in laboratories in India and the UK is described here, identifying four steps. First, samples were collected into a 2% (w/v) potassium dichromate solution. Second, oocysts were enriched by flotation in saturated saline. Third, genomic DNA was extracted using a QIAamp DNA Stool mini kit protocol including a mechanical homogenisation step. Finally, nested PCR was carried out using previously published primers targeting the internal transcribed spacer region 1 (ITS-1). Alternative methods tested included sample processing in the presence of faecal material, DNA extraction using a traditional phenol/chloroform protocol, the use of SCAR multiplex PCR (one tube and two tube versions) and speciation using the morphometric tool COCCIMORPH for the first time with field samples.     

Telegony,the Sire Effect and non‐Mendelian Inheritance Mediated by Spermatozoa: A Historical Overview and Modern Mechanistic Speculations

Telegony is the belief that the sire first mated to a female will have an influence upon some of that female’s later offspring by another male. Although the reality of telegony was acknowledged by such authorities as Darwin, Spencer, Romanes and many experienced breeders, it has been met with scepticism because of Weismann’s unfavourable comments and negative results obtained in several test experiments. In this article, alleged cases of telegony are provided. A search of the literature of cell biology and biochemistry reveals several plausible mechanisms that may form the basis for telegony. These involve the penetration of spermatozoa into the somatic tissues of the female genital tract, the incorporation of the DNA released by spermatozoa into maternal somatic cells, the presence of foetal DNA in maternal blood, as well as sperm RNA‐mediated non‐Mendelian inheritance of epigenetic changes.     

玉米品种真实性和纯度鉴定的SSR标记多重PCR体系优化

 为了建立稳定可靠的玉米真实性和纯度鉴定ＳＳＲ 标记,对ＤＮＡ 提取方法、ＳＳＲ 引物和多重ＰＣＲ 反应程序进行了优化。结果表明,用预热到７５℃以上的研钵和９５℃的１．５×ＣＴＡＢ提取缓冲液进行材料研磨,可得到纯度高、完整性好的ＤＮＡ,并且提取成本较低。利用软件ＰｒｉｍｅｒＰｒｅｍｉｅｒ５．０和Ｏｌｉｇｏ６．７２对玉米指纹鉴定的ＳＳＲ 核心引物进行重新分析与设计,建立了２１对ＳＳＲ 通用引物构成的８组多重ＰＣＲ 复合扩增体系和３步法扩增程序,均能在统一的ＰＣＲ 扩增条件下进行,扩增片段之间不存在交叉现象,扩增条带清晰,扩增结果稳定,这一扩增体系检测效率比单对ＳＳＲ 引物提高２．６倍以上。     

Abortion in goats by Caprine alphaherpesvirus 1 in Spain

An abortion outbreak occurred in a goat herd of Murciano‐Granadina breed in Almeria Region in Spain where 80 pregnant females aborted. All bacteriological and parasitological examinations resulted negative, whereas virological investigations and real‐time PCR assay showed the presence of Caprine alphaherpesvirus 1 DNA in the pathological specimens from aborted foetuses. Nucleotide sequence analysis revealed that the DNA was highly close related to the Swiss strain E‐CH (99.7%) and a little less extent to the Italian BA.1 strain (99.4%). Histopathological examination revealed multifocal, well‐circumscribed, 50‐ to 200‐μm‐diameter foci of coagulative necrosis in the liver, lungs and kidneys of three foetuses. In the periphery of the necrosis, there were frequently epithelial cells with the chromatin emarginated by large, round, amphophilic intranuclear viral inclusion bodies. The source of the infection in the herd could not clearly find out even some hypothesis were formulated. This seems to be the first report of an abortion outbreak due to Caprine alphaherpesvirus 1 in a goat herd in Spain.     

Anatomy, physiology and pathology of the amniotic and allantoic compartments in the sheep and cow

In both cows and sheep the allantoic fluid is confined to 2 sacs connected by a flattened isthmus, one in the non-pregnant horn and one in the upper part of the pregnant horn. The chorion encloses the amniotic and allantoic compartments, forming the amniochorion and chorioallantois, respectively. In the last third of gestation the compositions of both amniotic and allantoic fluids differ substantially from each other and from those of foetal urine, and maternal and foetal plasma. There is less variation in composition than in volume for a given gestational age. Abnormalities of volume are more common in cows than sheep, and hydrallantois is more common than hydramnois. Data obtained from both physiological experiments and pathological cases suggest that the foetal membranes play an important role in the regulation of composition and volume of foetal fluids. Evidence is presented that the permeability of the membranes to various solutes, as well as their capacity to produce and respond to a number of hormones, can affect the foetal fluid composition and/or volume. Progesterone, oestrogens and prolactin are some of the hormones known to affect foetal fluids. Foetal adrenal insufficiency has been associated with hydramnios implying a lack of hormones from this gland in this disease. The changes in allantoic fluid composition from normal to that closely resembling maternal/foetal extracellular fluid, in hydrallantois, suggests an alteration of membrane function as an aetiology and the continued production of fluid, after removal of the foetus in some cases, favours this hypothesis.     

单管套式PCR检测外源性禽白血病病毒

从贵州省4个养鸡场采集出现肿瘤病变或疑似肿瘤病料样本17份,以单管套式PCR方法检测禽白血病病毒长末端重复序列(LTR),15份病料均扩增出一条213 bp的DNA带,与预期扩增长度相符合,外源性禽白血病病毒的检出率达到88.2%.同时针对禽白血病病毒的囊膜糖蛋白基因(gp85)进行PCR扩增,在被检的17份病料中,7份检出J亚群特异性的DNA带(545 bp),占41.1%;9份检出A亚群特异性的DNA带(691 bp),占52.9%;其中2份病料同时检出J亚群与A亚群特异性的病原核酸.A、J亚群的PCR检出率低于LTR的套式PCR扩增.     

An investigation into the suitability of a commercial real‐time PCR assay to screen for Taylorella equigenitalis in routine prebreeding equine genital swabs

Reasons for performing study: Standard bacteriological methods for identifying Taylorella equigenitalis in cervical smears are time consuming. Therefore, a more rapid real‐time PCR assay was evaluated for its suitability in screening swabs. Objective: To compare the results of a commercially available real‐time PCR assay with routine microbiological culture for the identification of T. equigenitalis, the causative organism of contagious equine metritis, in equine genital swab samples, under ‘field trial’ conditions. Materials and methods: Routine prebreeding genital swabs (n = 2072) collected from Thoroughbred mares and stallions during 2009 were examined together with stored T. equigenitalis positive material. Swabs were cultured for T. equigenitalis using standard microbiological techniques. Bacterial lysates were isolated from the swabs and examined for the presence of a 16S DNA fragment of T. equigenitalis, using a commercial multiplex real‐time PCR assay system. Results: There was complete concordance between positive and negative results obtained by the 2 methods. Real‐time PCR also detected T. equigenitalis DNA from swabs that were negative using standard microbiological culture after 6 months' storage at +4°C but from which T. equigenitalis had been isolated following collection. The sensitivities of realtime PCR and bacterial culture were both 10^?3 (equivalent to 3 colony‐forming units). Conclusion and clinical relevance: Routine bacterial culture of T. equigenitalis requires an incubation period of not less than 7 days before a conclusive negative result can be obtained, whereas bacterial extraction and real‐time PCR assay can be completed in less than 6 h. The commercially‐available PCR assay tested provided a rapid and reliable method for the identification of T. equigenitalis from equine genital swabs and could be usefully employed for the screening of mares and stallions for preseason Horserace Betting Levy Board (HBLB) Code of Practice and in other situations such as for bloodstock sales screening requirements, overcoming the current delays imposed by bacterial culture requirements. Its use could be quality assured by the existing HBLB biannual testing scheme for designated laboratories.     

山羊绒毛干中线粒体DNA和核DNA的提取与PCR扩增

本研究以PCR缓冲液、MgCl2溶液和蛋白酶K为裂解提取液,建立了一种从山羊绒毛干中快速提取DNA的方法。结果表明,该方法不仅能从山羊绒毛干中提取出线粒体DNA和核DNA,而且能够有效地进行线粒体基因和核基因组基因的PCR扩增,为拓展羊绒样品在个体识别、遗传资源评价、分子进化和分子标记辅助育种等研究领域中的应用奠定基础。     

Detection of BHV-1 in a Naturally Infected Bovine Fetus by a Nested PCR assay

Bovine herpesvirus 1 (BHV-1) is frequently associated with abortion in naturally and experimentally infected cattle. Most of the virus isolation and immunofluorescent antibody protocols described in the literature for detecting BHV-1 in bovine foetuses are rather laborious, costly and time-consuming. The detection is described of BHV-1 in the tissues of a naturally aborted bovine foetus by a nested PCR assay with no further hybridization procedures.Optimal results were achieved by filtering the foetal tissues on a chromatography column before DNA extraction, by using two pairs of primers in a nested PCR and by evaluating the amplification products on silver-stained polyacrylamide gels.This nested PCR was faster and easier to perform than the virus isolation test. To our knowledge, this is the first time that BHV-1 has been detected in the tissues of a naturally infected bovine foetus by means of a nested PCR. The test seems to be a practical alternative for rapid detection of BHV-1 in bovine foetus.