Survey of levels of propetamphos and diazinon used to control sheep scab in Northern Ireland.

As a result of an increase in the incidence of sheep scab in Northern Ireland, the concentrations of propetamphos and diazinon were measured during 1987 and 1988 in fleece and liquid dip samples from selected flocks, including some in which inadequate dipping was suspected. Sixty-five per cent and 68 per cent of the liquid dip samples contained less than the manufacturer's recommended maintenance concentrations for propetamphos and diazinon respectively. The concentrations found in fleece were also lower than those found in sheep which were dipped with the recommended concentrations of propetamphos and diazinon in a controlled experiment.

Characterisation of acid dyes in forensic fibre analysis by high-performance liquid chromatography using narrow-bore columns and diode array detection.

A gradient elution high-performance liquid chromatographic (HPLC) system with a diode array detector and a short narrow-bore (40 x 1 mm I.D.) column has been used to characterise a number of acid dyes. The resolution and reproducibility of the HPLC system have been evaluated and the detection limits for various dyes have been estimated. Comparisons are made with current methods of fibre dyestuff examination used in forensic science. The system has been applied to the analysis of dye extracted from single fibres. Using diode array detection, both chromatographic and spectral data can be produced in a single operation from casework sized samples.

Isolation and characterization of high-molecular mass DNA from hair shafts.

Experiments to identify species by DNA analysis of their hair failed so far because no DNA could be isolated from hair shafts. In this work the preparation of DNA from human--as well as from animal hair shafts (alpaca, angora-rabbit, cashmere, cashgora, mohair, merino and yak) is described for the first time. In general the isolated DNA shows a length of more than 20 kbp. The species of the hair shaft samples could be exactly identified by DNA hybridization experiments. The isolated DNA from hair shafts allow new possibilities to identify species and individuals employing techniques from molecular biology.

Environmental contamination by heavy metals and fluoride in the Saeftinge salt marsh (The Netherlands) and its effect on sheep.

The Saeftinge salt marsh in the Westerschelde estuary (southwestern part of the Netherlands) represents one of the very few tidal brackish marsh ecosystems in Western Europe. From May 1983 to May 1985 the local pollution of this marsh with metals and fluoride was investigated. Samples from soil and vegetation were analysed monthly for cadmium, lead, copper, zinc, manganese, iron, and fluoride. The amount of these substances in the soil appeared to be related to both the percentage of clay particles and organic matter in the soil and to the frequency of tidal submergences. In vegetation, the pollutants clearly showed a seasonal variation. Adherent clay, deposited on the plants during submergences, contributed considerably to the total amount of these elements. Sheep grazing in the marsh were investigated for renal and faecal excretion of these elements, but no relation between these samples and the seasonal variation in vegetation was found. Presumably sheep consumed vegetation selectively, avoiding the more contaminated plants. Regular clinical inspections of the sheep revealed no signs of acute or chronic intoxication. The organs of sheep that died during the investigation showed increased levels of cadmium in the liver and kidney, and iron in the liver, but not enough to cause alarm. Fluoride found in the rib material, although slightly increased, did not indicate fluorosis. In conclusion, contamination with metals and fluoride, as observed in the salt marsh, apparently does not impair the health of locally grazing sheep. This may be due to selective consumption behaviour of the sheep, their stabling during the winter, limited biological availability of the elements studied, and a sheep management adapted to the local circumstances.

Protein reactions with methyl and ethyl vinyl sulfones.

Disulfide bonds of bovine serum albumin and wool were reduced by n-tributylphosphine to sulfhydryl groups that were then modified by methyl or ethyl vinyl sulfone in a nucleophilic addition reaction to S-(beta-ethylsulfonylmethyl)-L-cysteine and S(beta-ethylsulfonylethyl)-L-cysteine, respectively. The reductive alkylation was carried out either simultaneously, with both the reducing and alkylating agents present in the reaction mixture, or sequentially, with the reduced proteins first isolated before alkylation. Amino acid analysis studies showed that authentic, synthetic S-(beta-ethylsulfonylethyl)-L-cysteine eluted as a well-resolved peak after serine but that the peak associated with the corresponding methyl derivative overlapped the corresponding peak due to threonine. The extent of alkylation of the sulfhydryl groups of cysteine, epsilon-NH2 of lysine, and NH groups of the imidazole ring of histidine was also measured by amino acid analysis. The results show that alkyl vinyl sulfones have a strong chemical affinity for protein functional groups.

Wool proteins of New Zealand Romney sheep.

Proteins extracted from the wool of 65 Romney ewes were analysed qualitatively by one- and two-dimensional polyacrylamide gel electrophoresis. Romney wool proteins could be classified into the low-sulfur, high-sulfur, and high-tyrosine protein groups described for wool from other breeds. The wool protein pattern of an individual sheep remained constant despite changes in season, age or nutritional status of the sheep, and did not vary between different body positions. There were between-sheep differences in protein pattern, most variation occurring in the high-sulfur protein group. These differences were presumed to reflect genetic differences between the sheep.

Cystine-rich proteins of human hair: characterization and structure as revealed by reversed-phase and size-exclusion high-performance liquid chromatography.

The human hair cystine-rich proteins have been separated through the combined use of reversed-phase and size-exclusion chromatography into more than fifty components. These have been grouped, based on molecular weight, into six families of closely related members. The families range in molecular weight from less than 6500 for the low-molecular-weight components to more than 67 000 for the high-molecular-weight components, with average intermediate values for the other families of 8000, 11 500, 15 500 and 19 000. The results also suggest an organized structure of the hair matrix proteins. The combined use of reversed-phase and size-exclusion high-performance liquid chromatography in these studies presents an example where the quaternary structure of a multi-component protein can be largely deduced from its chromatographic behaviour.

Clustered arrangement of keratin intermediate filament genes.

We report here that component members of the keratin intermediate filament (IF) type I and type II gene families of sheep are closely linked but apparently the two families are not. Nine genes, accounting for up to half of the keratin IF gene repertoire, were mapped in four cosmid clones and the linkage between the genes ranged from several kilobases to 20 kilobases. In one cosmid, three tandem type I genes had the same transcriptional arrangement and were regularly spaced. In another cosmid, tandem genes encoding type II keratins were identified and, surprisingly, a solitary exon was discovered in the intergene region between the two type II genes. In a normal gene this exon encodes one of the most conserved amino acid regions of IF proteins, the C-terminal end of the alpha-helical core. Homologous C-terminal protein subdomains were encoded by two wool keratin type II genes and we suggest that this arrangement may also exist in the other wool keratin type II genes.

Localization of low-sulfur keratin proteins in the wool follicle using monoclonal antibodies.

Monoclonal antibodies that recognize components of the low-sulfur keratin proteins extracted from Merino wool have been used to locate these components within the wool follicle. Immunoblotting procedures showed that all of the monoclonal antibodies bound more than one of the eight low-sulfur protein components, indicating that these proteins have antigenic determinants in common. Immunofluorescence studies showed that those antibodies specific for the component 7 family of the low-sulfur proteins bound to the developing wool fiber, whereas those antibodies recognizing the component 8 family bound to areas throughout the wool follicle, particularly the inner and outer root sheaths, but also to the fiber, the cuticle, and the epidermis. One of the monoclonal antibodies also bound to intermediate filament networks of cultured human epithelial cells.

Effects of double decking and space allowance on the performance and behavior of feeder lambs.

A 2 X 2 factorial experiment was conducted using growing lambs to compare single-level vs double-decked pens and high (.32 m2/lamb) vs low (.48 m2/lamb) densities. Three replicates of each treatment combination were involved using 30 lambs/pen. In the double-decked pens, an upper deck located over the rear section of the lower level provided one-third of the total floor area. Feed and water were provided on the lower level only and lambs could move freely between levels by means of a slatted ramp. All floors were of expanded metal. Use of the various areas of the pens was determined during a 24-h observation and by a videotape recording of the double-decked pens during the daylight hours. Fleece contamination was determined by visual observation and standard wool testing procedures. Gain was determined over the 8-wk period of each replicate. The high density treatment resulted in 1.5 kg/lamb (10%) less gain (P less than .01) and, in the case of double-decked pens, different patterns of space utilization compared with the low density treatment. Lambs in the low density pens were able to move more successfully from resting areas to the feeding area in the afternoon (P less than .01). The double-decked system did not significantly affect weight gain, but resulted in dirtier fleeces (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Sheep keratins: characterization of cDNA clones for the glycine + tyrosine-rich wool proteins using a synthetic probe.

cDNA clones coding for the high-glycine + tyrosine (HGT) proteins of sheep wool keratin have been isolated and sequenced. Clones were identified using a 25-base synthetic oligonucleotide probe, deduced from the amino acid sequence of a HGT protein present at about 0.4% in the wool fibre. Southern and Northern blot analysis suggest that the gene is present as a single copy in the genome and is transcribed as an mRNA species, 600 bases in size.

Selenium concentration in the blood and wool and glutathione peroxidase activity in the blood of three breeds of sheep.

The activity of the enzyme glutathione peroxidase (GSH-Px) in whole blood and the selenium concentrations in whole blood and wool were measured in samples taken from 15 Scottish Blackface, 16 Welsh Mountain and 16 Finnish landrace sheep. Blood selenium sheep had almost twice the GSH-Px activity and blood selenium concentration of the other two breeds (P less than 0.001). Wool selenium concentrations of the three breeds were not significantly different. Blood selenium concentration and GSH-Px activity were highly correlated (r = 0.8, P less than 0.01) but wool selenium concentration was not significantly correlated with either of these measurements.

Structural studies on the microfibrillar proteins of wool. Interaction between alpha-helical segments and reassembly of a four-chain structure.

The alpha-helix-rich particle of Mr 50 200, derived by limited alpha-chymotryptic digestion of the solubilized microfibrillar proteins from wool alpha-keratin, consists mainly of polypeptide-chain segments of Mr 12 500 (fraction ChC) and 25 000 (fraction ChB). The 12 500-Mr segments are of two types (I and II), which are derived from different polypeptide chains of the microfibrillar complex. Each of these type-I and type-II segments partially self-associates in benign solvents to form either dimers or tetramers. When mixed, the two segments show changes in physical properties (alpha-helix content, difference spectra and molecular weight) indicative of complex-formation. The maximum changes occur when the two segments are mixed in an equimolar ratio. Complexes isolated after rapid dialysis of mixtures from 8 M-urea solution were examined by various methods. A tetrameric structure is the main product formed in all cases, and the maximum amount of tetramer is obtained from equimolar mixtures of the type-I and type-II polypeptides. When urea is removed by dialysis from the unfractionated 12 500-Mr segments (fraction ChC) or from the alpha-helix-rich particle itself, a similar complex of Mr 50 000 is formed. The physical properties of these reconstituted entities (alpha-helix content, molecular weight, thermal stability and exposure of tyrosine residues) are similar to those of the original alpha-helix-rich particle. Cross-linking experiments with dimethyl suberimidate are in agreement with a four-chain complex for the reassembled structures. A pair of double-stranded alpha-helices is proposed for the particle, and is considered to be an integral part of the microfibrillar complex in wool alpha-keratin.

Observations on fibre diameter variation of sheep in relation to fleece-rot and body strike susceptibility.

A comparative study of various fleece properties known to influence fleece-rot susceptibility was made in a merino flock consisting of sheep which were found to be either resistant or susceptible to fleece-rot and body strike following heavy rains. The fleece properties measured were fibre diameter, fibre diameter, fibre diameter variation, wax content, suint content, wax to suint ratio, suint pH, insoluble nitrogen content, wool colour and wettability. Fibre diameter variation, due mainly to the presence of coarse, secondary fibres in the staple, was the only fleece property which differed significantly (p less than 0.001) between resistant and susceptible animals. The coefficient of variation of fibre diameter was lowered from a mean value of 22.7 +/- 0.3% in susceptible sheep to 20.0 +/- 0.3% in resistant sheep. A causal relationship between high fibre diameter variation and fleece-rot susceptibility is suggested. Sheep with irregular fibre size may retain free moisture in the fleece for longer, and thereby become more susceptible to fleece-rot than sheep with uniform fibre diameter, other predisposing factors being equal.