Genotyping cattle for inherited congenital myoclonus and maple syrup urine disease

OBJECTIVE: To develop a routine procedure for establishing the inherited congenital myoclonus (ICM) genotype of cattle and to obtain an estimate of the prevalence of heterozygotes for ICM and maple syrup urine disease (MSUD) in Australian Poll Herefords. DESIGN: A mismatch amplification procedure was developed to genotype for ICM. The ICM and MSUD genotypes of subjects from a 'neuraxial oedema' experimental breeding herd were investigated. Tail hair roots were used as a source of target DNA to determine the ICM and MSUD genotypes of 455 Poll Hereford bulls. RESULTS: An Acc I mismatch procedure was found to be suitable to genotype cattle for the ICM alleles using tail hair roots as the source of DNA. Based on the prevalence of heterozygotes among saleyard and sale bulls in the early 1990s, and contemporary slaughter bulls, the frequencies of the alleles responsible for ICM and MSUD were estimated to be between 0.01 and 0.02. CONCLUSION: This survey demonstrates that the mutations responsible for ICM and MSUD are present in the Australian Poll Hereford population. PCR tests could be used to advantage in differential diagnosis of neurological disease in newly born calves and in selection of Poll Hereford seed stock.     

Prion protein (PrP) gene polymorphisms associated with natural scrapie cases and their flock-mates in Ireland

The PrP genotypes associated with natural scrapie in Ireland were determined and a comparison was made between genotypes found in scrapie-infected sheep and those found in healthy animals from scrapie-infected flocks. Seven PrP genotypes were identified in scrapie-infected animals: VV(136)RR(154)QQ(171),VA(136)RR(154)QQ(171),VA(136)RR(154)QR(171),VA(136)RR(154)QH(171),AA(136)RR(154)QQ(171),AA(136)RR(154)QH(171) and AA(136)RR(154)HH(171). Of 11 scrapie-infected flocks, 15 genotypes were identified in the healthy flock-mates. The genotypes identified in scrapie-affected animals were also all identified in healthy flock-mates. In 9 of the 11 flocks studied, the genotype frequencies among scrapie-infected animals were significantly different from those among healthy flock-mates. The results show that there is a significant risk of developing the clinical signs of scrapie associated with particular PrP genotypes in the Irish sheep population. The association between the V(136)R(154)Q(171) allele and scrapie was evident, as was the association between A(136)R(154)R(171) and resistance to developing the clinical signs of scrapie. The presence of the A(136)H(154)Q(171) allele in the flocks examined resulted in a decreased risk of developing scrapie compared to the presence of the A(136)R(154)Q(171).     

Changes in urinary and plasma oestrone sulphate concentrations after induction of foetal death in mares at 45 days of gestation

Foetal death was induced in 10 Standardbred mares at day 45 of gestation by injecting 20 to 45 ml of hypertonic (24% W/V) saline into the conceptus at surgery. Ten mares underwent sham treatment and acted as controls. Blood and urine samples were collected every other day between days 30 and 45 post ovulation and at 0, 3 and 6 h relative to the infusion of saline in the treated mares, or sham treatment in control mares. Blood and urine samples were then collected daily between days 46 and 55 post ovulation. Urine oestrone sulphate (E1S) concentrations, measured by radioimmunoassay, increased between day 34 and day 36 of gestation in treated and control groups. In mares in which foetal death was induced, urine E1S concentrations declined post-operatively and were significantly (p less than .05) lower than controls by day 50. In plasma, E1S concentrations showed a major increase between days 36 and 40 in both groups. This was followed by a rapid decline after treatment in saline-injected mares, so that by day 48 plasma E1S concentrations in treated mares were significantly (P less than .05) lower than the controls. The results show that urinary and plasma E1S concentrations rise rapidly during early pregnancy, and are associated with a viable foetus after day 45 of pregnancy.     

Reproductive performance of Thoroughbred mares on six commercial stud farms

The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the first served oestrous cycle (77.8%) than in mares that needed two served oestrous cycles to become pregnant (65.4%). Of all diagnosed pregnancies, 19.5% were not completed. Pregnancy loss was lower (P < 0.05) in maiden (12.4%) than in barren (19.7%) or foaling (20.9%) mares. Twins were diagnosed in 7.8% of all pregnancies. If one conceptus was lost without external interference, 84.1% of pregnancies went to term. If one conceptus was manually crushed, 55.9% of pregnancies were maintained. If prostaglandin was used to terminate twin pregnancies, 60% of mares so treated produced foals the following year.     

In planta transient expression as a system for genetic and biochemical analyses of chlorophyll biosynthesis

Background  

Mg chelatase is a multi-subunit enzyme that catalyses the first committed step of chlorophyll biosynthesis. Studies in higher plants and algae indicate that the Mg chelatase reaction product, Mg-protoporphyrin IX plays an essential role in nuclear-plastid interactions. A number of Mg chelatase mutants have been isolated from higher plants, including semi-dominant alleles of ChlI, the gene encoding the I subunit of the enzyme. To investigate the function of higher plant CHLI, bacterial orthologues have been engineered to carry analogous amino acid substitutions to the higher plant mutations and the phenotypes examined through in vitro characterization of heterologously produced proteins. Here, we demonstrate the utility of a transient expression system in Nicotiana benthamiana for rapidly assaying mutant variants of the maize CHLI protein in vivo.     

An assessment of potential pesticide transmission,considering the combined impact of soil texture and pesticide properties: A meta-analysis

Pesticides are widely employed as a cost-effective means of reducing the impacts of undesirable plants and animals. The aim of this paper is to develop a risk ranking of transmission of key pesticides through soil to waterways, taking into account physico-chemical properties of the pesticides (soil half-life and water solubility), soil permeability, and the relationship between adsorption of pesticides and soil texture. This may be used as a screening tool for land managers, as it allows assessment of the potential transmission risks associated with the use of specified pesticides across a spectrum of soil textures. The twenty-eight pesticides examined were differentiated into three groups: herbicides, fungicides and insecticides. The highest risk of pesticide transmission through soils to waterways is associated with soils containing <20% clay or >45% sand. In a small number of cases, the resulting transmission risk is not influenced by soil texture alone. For example, for Phenmedipham, the transmission risk is higher for clay soils than for silt loam. The data generated in this paper may also be used in the identification of critical area sources, which have a high likelihood of pesticide transmission to waterways. Furthermore, they have the potential to be applied to GIS mapping, where the potential transmission risk values of the pesticides can be layered directly onto various soil textures.     

Optimizing Electrical Activation of Porcine Oocytes by Adjusting Pre‐ and Post‐Activation Mannitol Exposure Times

Modifying electrical activation conditions have been used to improve in vitro embryo production and development in pigs. However, there is insufficient information about correlations of porcine embryo development with oocyte pre‐ and post‐activation conditions. The purpose of this study was to compare the developmental rates of porcine oocytes subjected to different mannitol exposure times, either pre‐ or post‐electrical activation, and to elucidate the reason for the optimal mannitol exposure time. Mannitol exposure times around activation were adjusted as 0, 1, 2 or 3 min. Blastocyst development were checked on day 7. Exposure of oocytes to mannitol for 1 or 2 min before electrical activation produced significantly higher blastocyst rates than exposure for 0 or 3 min. There was no significant difference in blastocyst rates when activated oocytes were exposed to mannitol for 0, 1, 2 or 3 min after electrical activation. While exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation showed significantly higher blastocyst development than 0 min pre‐ and 0 min post‐activation. It also showed higher maintenance of normal oocyte morphology than exposure for 0 min pre‐ and 0 min post‐activation. In conclusion, exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation seems to be optimal for producing higher in vitro blastocyst development of porcine parthenogenetic embryos. The higher blastocyst development is correlated with higher maintenance of normal morphology in oocytes exposed to mannitol for 1 min pre‐ and 3 min post‐activation.     

The Impact of Biochar Addition on Nutrient Leaching and Soil Properties from Tillage Soil Amended with Pig Manure

Poses dam in the Seine River estuary acts as receptacle of water drain-offs from highly urbanized and industrialized catchment area; therefore, this water is highly contaminated by trace metals. Most trace elements are mainly bound to particulate matter and are incorporated rapidly into the sediments. Scavenging of these metals in the sediments can be reversible due to several perturbations so as sediments also act as a source of pollutants for the overlying water. For instance, natural events (tide, flood, storm) and anthropogenic processes (water management actions) can cause disturbance of sediments and subsequent remobilization of pollutants to the water column, thereby posing a potential threat for aquatic organisms. The purpose of this study was to evaluate the mobility of trace metals by different methods in the Seine estuary sediments. The surface sediment sampled at Poses dam was characterized by high pollution level of Cd, Cu, Zn, and Pb. The estimation of metal bioavailability through ratio ΣSEM/AVS (simultaneously extracted metals/acid volatile sulfides) indicates a potential bioavailability of trace metals. The chemical partitioning using the European Community of Bureau of Reference sequential extraction method revealed that over 85, 82, and 80 % of the total Cd, Zn, and Pb, respectively, were found to be associated with the exchangeable and reducible fractions of the sediment. Another approach used consists in the quantification of dissolved metals released by sediment resuspension experiments in laboratory under controlled conditions. The results indicated that metals are released rapidly from sediment with a sharp peak at the beginning of the experiment, followed by a fast coprecipitation and/or adsorption processes on the suspended particles. Also, the Cd, Pb, and Ni mobility is higher compared to that of the other metals.