The biotrophic, non-appressorium-forming grass pathogen Claviceps purpurea needs a Fus3/Pmk1 homologous mitogen-activated protein kinase for colonization of rye ovarian tissue.

Claviceps purpurea is a common pathogen of a wide range of grasses and cereals that is able to establish a stable, balanced interaction with its host plant and is considered a biotroph. It does not form special penetration structures such as appressoria. To study the signaling processes involved in this special host-pathogen interaction, we have cloned a gene, cpmk1, encoding a mitogen-activated protein (MAP) kinase that shows significant homology to Fus3 of Saccharomyces cerevisiae and to pmk1 of Magnaporthe grisea. Using a gene-replacement approach, we isolated a Acpmk1 mutant and characterized it in detail. Loss of CPMK1 has no obvious effect on vegetative properties (such as growth rate, morphology, and conidia formation); however, infection tests on rye show that the mutant is unable to colonize rye tissue, i.e., it appears to be completely nonpathogenic. Complementation of the mutant with a wild-type copy of cpmk1 fully restores its pathogenicity, confirming that this MAP kinase is essential for infection of rye by C. purpurea. Transformation of the delta pmk1 mutant of M. grisea with a complete copy of cpmk1 (including the C. purpurea promoter) fully restored its ability to form appressoria and its pathogenicity on barley. Although both fungi drastically differ in their pathogenic strategies, this result indicates that the signal pathway involving CPMK1 is highly conserved.

Mutation of a putative AMPK phosphorylation site abolishes the repressor activity but not the nuclear targeting of the fungal glucose regulator CRE1.

In filamentous ascomycetes, glucose repression is mediated by CRE1, a zinc-finger protein related to Miglp from yeast. Five putative AMPK phosphorylation motifs identified in the glucose repressor from the phytopathogenic fungus Sclerotinia sclerotiorum were mutated in a GFP::CRE1 translational fusion. Complementation experiments in Aspergillus nidulans and fluorescence microscopy analyses showed that mutation of one site (Ser266) abolishes the repressor activity of the fusion protein but not its nuclear targeting, suggesting that an AMPK protein kinase may be involved in the function of the fungal glucose repressor.

Expression and compartmentation of the glucose repressor CRE1 from the phytopathogenic fungus Sclerotinia sclerotiorum.

The glucose repressor from the phytopathogenic fungus Sclerotinia sclerotiorum is encoded by the cre1 gene. Polyclonal antibodies were raised against a fusion protein (gluthathione S-transferase) GST-CRE1 in order to study cre1 expression. Western blot analyses revealed that CRE1 synthesis is regulated by the nature of the extracellular carbon source. High CRE1 levels are induced by glucose and remain stable after transfer into pectin medium, suggesting the existence of post-translational mechanisms which inactivate CRE1 to allow transcription of glucose-repressed genes. Subcellular fractionation demonstrated that CRE1 is localized in the nuclei of glucose grown hyphae and in the cytoplasm when glucose is removed from the culture medium. CRE1 fused to green fluorescent protein (GFP) was introduced into Aspergillus nidulans. Fluorescence microscopy showed the nuclear localization of the GFP-CRE1 fusion protein according to the presence of glucose in the culture medium, suggesting homologous post-translational regulations of glucose repressors in fungi. We propose that filamentous fungi regulate the activity of the glucose repressor by controlling its nuclear translocation.

Improved electronic gate technique, for particle counting and sizing in liquids.

Particle counting and measurements of particle size distributions in liquids can be based on pulse height analysis of signals obtained from a changing gate impedance, upon particle transition. Signal-to-noise ratio is markedly improved, making use of a four-electrode detector. An instrumentation amplifier with a high-pass filter is used as a preamplifier. Cylindrical electrodes and a coaxial aperture location result in a decreased detector capacitance, lowering the signal detection level and contributing to improved pulse shape. Volume sampling is flexible and accurate, making use of a stepping motor actuated digital sampling system. A newly developed baseline restorer, combined with a log-antilog amplifier circuit, allows for linearisation of the pulse height/particle size relationship.

Electric current distribution in tissues upon electrotherapy.

The authors have used computer simulations to study electric current distribution in tissues upon electrotherapy. The results are shown on a computer plot and apply to various types of current. Simulations on a simplified circular structure (as a model of a limb cross section) give a better understanding of the problem and clearly demonstrate the influence of electrode position and geometry. Simulations have established the possibility of directing the current density at particular internal areas. The greatest current density occurs close to the surface of the bone in an area midway between the electrodes, and larger electrodes may make treatment more effective. These conclusions are verified in the more realistic structure of a thigh cross section and extrapolation to a length section is made. Finally, the influence of metallic implants is considered. The conclusions of this work are of great practical interest to electrotherapy, particularly electrode techniques.

Investigation into the heredity of congenital lateral patellar (sub)luxation in the Shetland pony.

A breeding experiment was carried out in a group of Shetland ponies in order to investigate the heredity of congenital lateral patellar (sub)luxation. A breeding herd was established and consisted of stallions and mares acquired at different times. Some were free from, and others were affected by lateral patellar (sub)luxation in either one or both femoropatellar joints. Over a period of 20 years, 49 foals were born from different mating combinations. Some offspring were free from the defect and others showed the abnormality. Though the number of foals bred during the experiment is rather small, there is sufficient evidence to suggest a monogenic autosomal recessive hereditary transmission of the defect.

[Genetics and latent defects in animals. II. Microphthalmia in sheep (author's transl)]. / De genetica en de verborgen gebreken bij dieren. II. Microphthalmus bij het schaap.

In this second clinical paper, the genetic features of the case of microphthalmia in sheep reported by Wagenaar is discussed in greater detail. The situation is compared with that on breeding other animal species in the Netherlands. Probability calculations based on the situation described are carried out. The replies by experts appointed by the Court of Justice are commented upon.

[Purposeful (blood-)horse breeding (author's transl)]. / Deolgerichte (warmbloed-)paardenfokkerij.

Horse-breeding in the Netherlands is briefly reviewed. Particular attention is paid to the number of foals of various breeds. Some effects of inbreeding in Friesian horses are discussed. As regards methods selection, attention is mainly paid to saddle horses. The role of veterinarians (from the point of view of selection for soundness) is described. Selection is based on the results of studies in the Faculty of Veterinary Medicine in Utrecht. A number of these results are reviewed.

[Preliminary performance test in saddle horses (author's transl)]. / Voorlopige eigen prestatietoets van rijpaardhengsten

The study of the literature on a preliminary performance test for saddle horses (stallions) is concerned with European countries. Interest is found to be increasing in the various countries. Performance of the test in the Netherlands (since 1966) is described and the various criteria of evaluation are discussed in detail. The intensity of selection based on this test is referred to. In 1974, it was 78 per cent in the Netherlands. Part of studies on the relationship between some results of testing are reviewed. The traction test shows a very low coefficient of correlation with the other parts of the examination. The contemplated analysis of the results of progeny groups is discussed. In the comment, the fact is stressed that there should be more international co-operation in this field. Finally, the preliminary performance test is considered as part of the criteria adopted in the selection of saddle horses in the future.

[Carcass composition of newborn (Dutch-Friesian and Meuse-Rhine-Yssel) bull calves (author's transl)]. / Karkassamenstelling van pasgeboren (F.H. en M.R.IJ.) stierkalveren

The quantitative aspects of the composition of the carcases of newborn bull calves were studied. Fifty bull calves of the Dutch-Friesian and fify of the Meuse-Rhine-Yssel breed, all of which were third calves of pedigree cows, were purchased, slaughtered and anatomically dissected. Several of the muscles which are of interest to retailers have been identified both by their Dutch and by their Latin names. At an age of nearly five days, calves of the Dutch-Friesian breed weighed 39.5 kg., those of the Meuse-Rhine-Yssel breed weighing 42.5 kg. The height at withers of calves of the Dutch-Friesian breed was 70 cm. and that of calves of the Meuse-Rhine-Yssel breed was 68.7 cm. The carcass dressing percentage was identical in the two breeds, being 61.2 per cent. The composition of the muscles of the fore-quarters as well as that of the muscles of the hind-quarters showed slight significant differences between the two breeds. This is a striking feature, the more so these breeds were not separated until the early part of the present century. Coefficients of correlation are given for many of the magnitudes studied. Moreover, bilateral dissection was carried out in eighty-eight carcases. This showed that, on an average, the left half of the carcass was heavier than the right half. Those components of the weight, which were mainly involved, are stated. The literature was studied with special reference to the following subjects: aspects affecting the birth weight, the relationship between birth weight and meat production and the ratio between the weight of muscles within the carcases.

Polysensory interactions in the cuneate nucleus.

1. The effects of light flashes or sound clicks on somatic sensory activity in the cuneate nucleus of the cat were studied. Polysensory interactions were demonstrated by means of gross potential recording in the cuneate nucleus or medial lemniscus, single unit recording in the cuneate nucleus, and excitability testing of tract terminals.2. Brief flashes or clicks were found to produce negative (N) and positive (P) waves in the cuneate nucleus similar to those produced by cutaneous stimulation. Furthermore, the P wave evoked by conditioning photic or acoustic stimuli depressed the P wave produced by cutaneous test stimuli.3. Conditioning photic or acoustic stimuli inhibited spontaneously firing cuneate neurones as well as those driven by cutaneous test stimuli.4. Conditioning photic or acoustic stimuli depressed the test discharge in the medial lemniscus evoked by cutaneous test stimuli.5. Micro-electrode stimulation within the cuneate nucleus evoked an antidromic response in the superficial radial nerve consisting of two spike complexes. Conditioning photic or acoustic stimuli caused an increase in the size of the initial spike complex and a depression in the secondary spike complex. These changes and the time courses of all the interactions observed were suggestive of presynaptic inhibition.6. The modulatory influences of photic and acoustic stimuli on the cuneate nucleus were present under alpha-chloralose or pentobarbitone anaesthesia and the acoustic influence persisted after midcollicular decerebration. When added to other evidence, the above findings suggest that the reticular formation of the brain stem plays an important role in these polysensory interactions.

Visual and auditory inputs into the cuneate nucleus.

Sound clicks or light flashes modify somatic sensory activity in the cuneate nucleus of the cat. The techniques of gross potential recording in the cuneate nucleus or medial lemniscal tract, of single unit recording in the cuneate nucleus, and of excitability testing of cuneate terminals demonstrate this heterosensory interactionsensory interaction.