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A study of selected transcripts in rice leaves was performed using a number of cDNA clones from barley as probes. The transcripts for the pathogenesis–related proteins, PR-1, PR-2, PR-3, PR-4 and PR-5, and for a peroxidase were found to accumulate strongly in response to the non-rice pathogen Bipolaris sorokinianaand moderately in response to a virulent isolate of Pyricularia oryzae (Magnaporthe grisea) and u.v. light. A weak accumulation was observed in response to an avirulent isolate of P. oryzae. PR-protein transcript accumulation was seen 12 h after inoculation with B. sorokinianaand after exposure to u.v. light. These transcripts reached maximum accumulation levels at 24 h and all declined thereafter with the exception of the PR-4 transcript in response to B. sorokiniana. Maximum accumulation of the peroxidase transcript occurred at 12 h in response to both B. sorokinianaand u.v. light. These PR-protein and peroxidase transcripts were later expressed markedly in response to avirulent and virulent isolates of P. oryzae. They were barely detectable at the early time points, while maximum transcript levels occurred towards the end of the experiment, i.e. 120 h after inoculation. Interestingly, all these transcripts accumulated to a higher level in the compatible than in the incompatible interactions between rice and P. oryzae. Transcripts for chalcone synthase, oxalate oxidase and an oxalate oxidase-like protein were not detectable using the heterologous barley clones, whilst 14-3-3 protein and O-methyltransferase transcripts were seen to be constitutively expressed.

The putative master transcript of a novel class of repetitive element has been cloned from the fungusErysiphe graminis f.sp.hordei. Sequence analysis of the cDNA revealed that the element, designatedEg-R1, is a member of the retroposon superfamily with properties in common with SINEs and LINEs (short orlonginterspersedelements). SINE-like properties include the transcript size (approximately 700 bp), and the lack of major open reading frames. In contrast, the fact that the transcript is polyadenylated and is most probably transcribed by RNA polymerase II, suggests a functional relationship to LINEs. Except for a short, but striking, sequence identity to a published SINE from the same fungus, no similar sequence was found in database searches. A constitutively high transcript level is found throughout the asexual life cycle of the fungus. Small differences in band patterns on Southern blots were observed between two isolates ofE. graminis f.sp.hordei, while the band patterns in an isolate of the very close relativeE. graminis f.sp.tritici in general appear dissimilar. This may imply that the element is currently active. Recent dispersal is confirmed by the observation that an approximately 550 bp internalHinfI fragment is conserved in the majority of the copies in all three isolates. Approximately 50 copies are present inE. graminis f.sp.hordei.

Without Abstract:

Total hip replacement was performed in 27 patients aged 80 years and older. In the early postoperative period, medical complications occurred in 13 patients and arthroplasty‐related complications in 5 patients. At the time of the follow‐up, after an average of 31 months, there was one case of acetabular cup loosening, which was revised. Twenty of 22 patients were free from pain at rest, and the social function of the patients had remained almost unchanged.

Reduction of human thyroid membranes with dithiothreitol caused the release of a water-soluble glycoprotein which neutralized the thyrotropin (TSH) receptor-binding and thyroid-stimulating activities of Graves‘ serum. Analysis of the protein by gel filtration and sucrose density gradient centrifugation allowed estimates of 3.45 nm for the Stokes’ radius, 3.6 S for the s20,w and 47 000 +/- 5000 (mean +/- S.D.; n = 4) for the Mr. The material released by dithiothreitol treatment could be crosslinked to 125I-labelled TSH coupled to N-hydroxysuccinimidyl 4-azidobenzoate (125I-HSAB-TSH), suggesting that it contained a component of the TSH receptor. Furthermore, analysis of the crosslinked material by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated that it contained the TSH receptor A subunit (Mr 50 000). Several factors suggested therefore that the glycoprotein released by dithiothreitol treatment of human thyroid membranes was the TSH receptor A subunit. In particular, (a) both preparations were hydrophilic and were released from membranes by reduction, (b) they had similar Mr values and (c) both preparations crosslinked to 125I-HSAB-TSH. Material similar to the TSH receptor A subunit was released from thyroid membranes by treatment with papain, probably as a result of cleavage of the receptor A subunit at a site close to the interchain disulphide bridge. A similar mechanism, involving thyroid proteinases, was probably involved in release of material with similar properties to the TSH receptor A subunit during freezing and thawing of human thyroid homogenates.

The relationship between the binding of thyrotrophin (TSH) to receptors and the production of cyclic AMP has been investigated using crude human thyroid membranes. Receptor binding was studied by use of 125I-labelled bovine TSH, which had been purified by absorption to and elution from human thyroid membranes. This 125I-labelled material showed the same biological activity as the unlabelled hormone. Binding studies at equilibrium indicated that the association constant of the TSH–membrane interaction decreased as the amount of TSH bound increased. Kinetic data did not provide definite evidence that this was due to an effect of increasing receptor occupancy on the dissociation rate constant. Detectable stimulation by TSH of cyclic AMP production by the membranes was observed with as little as 30 μu. (1 ng) hormone. Increasing amounts of TSH over the range 0–250 μu. caused increases in the production of cyclic AMP, proportional to the amount of hormone bound. With larger amounts of TSH, increasingly greater amounts of bound hormone were required to give corresponding increases in cyclic AMP formation, and addition of TSH in amounts greater than 16 mu. resulted in progressive inhibition of cyclic AMP formation. Kinetic studies indicated that receptor binding was not rate-limiting in the stimulation of cyclic AMP production by TSH.

Thyroid-stimulating antibodies (TSAb) were found to inhibit the binding of labelled thyrotrophin (TSH) to thyroid membranes in a dose-dependent manner and this effect was localized in the Fab part of the TSAb molecule. Analysis of the binding data suggested that TSAb and TSH bound to the same receptor site. Production of cyclic AMP by the thyroid membranes was stimulated by TSAb and TSAb–Fab with a similar time course to that observed with TSH. Kinetic studies indicated that the binding of TSAb to the thyroid membranes was not rate-limiting in the process of stimulation of cyclic AMP production.

Without Abstract:

Thyrotrophin (TSH) receptors have been extracted from human and porcine thyroid membranes by treatment with Triton X-100.125I-Labelled bovine TSH was used to monitor receptor activity. Analysis by gel filtration and electrophoresis on acrylamide gels containing sodium dodecyl sulphate suggested that Triton extracts of human thyroid membranes contained TSH receptors with a molecular weight in the region of 50 000 closely associated with Triton micelles of approximate molecular weight 300 000. Isoelectric focusing studies indicated that the Triton-solubilized TSH binding activity had an isoelectric point of pH 4–4·5. The soluble TSH receptors were heat-labile, showed optimum TSH binding at pH 7·4 and reduced hormone binding at high ionic strength. The TSH binding characteristics of membrane-bound and solubilized human TSH receptors were similar and both preparations gave curved Scatchard plots.Solubilized porcine TSH receptors appeared to have a similar molecular weight to the human receptors and were also closely associated with Triton micelles of approximate molecular weight 300 000. Scatchard analysis of TSH binding to membrane-bound or solubilized porcine TSH receptors gave approximately linear plots with association constants of 2·8 ± 0·95 (s.e.m.) × 109and 1·7 ± 0·27 × 1091/mol respectively. Comparison of the binding capacities of the solubilized and membrane-bound porcine receptors indicated that the 0·5% Triton extracts contained 40% of the original TSH binding activity and that this was present at a concentration of 25 ng/ml.

A review is given of the problem of hot-salt stress cracking of titanium which covers: steady-state threshold data, environmental effects, mechanism of attack and preventive measures. The conditions to produce hot-salt cracking under static steady-state conditions are well defined. But, there is yet no rationale for the lack of a single part failure in aircraft flight. Effective preventive measures include: shot peen-ing, metallic coatings, special heat treatments and alloy selection. The Beta III alloy shows a high salt-cracking threshold even after heat treatment to high strength levels.