The unique insert of cellular and viral fms protein tyrosine kinase domains is dispensable for enzymatic and transforming activities.

The receptors for colony stimulating factor-1 (CSF-1), platelet derived growth factor and the c-kit protein tyrosine kinase (PTK) contain within their catalytic domains a stretch of 60-100 residues, largely unrelated in sequence, with no counterpart in other PTKs. Of the 64 amino acids within this kinase insert, 58 were deleted from the mouse CSF-1 receptor by oligonucleotide-directed mutagenesis. The mutant CSF-1 receptor was not markedly affected in its kinase activity, post-translational processing or its ability to induce autocrine transformation of NIH 3T3 mouse fibroblasts. Similarly, retention of kinase and transforming activities were observed following deletion of part or all of the kinase insert from the v-fms oncoprotein. The c- and v-fms kinase inserts were probed using monoclonal and polyclonal antibodies and were found to be highly antigenic. Two monoclonal antibodies raised to the v-fms cytoplasmic domain both recognized epitopes within the insert, and bound enzymatically active v-fms glycoproteins. These results indicate that the fms kinase insert is located on the surface of the protein and folds separately from the rest of the catalytic domain, but is not required for the biological activity of fms PTKs ectopically expressed in mouse fibroblasts. The insert may therefore play a specific function in cells such as monocytes and trophoblasts that normally express the CSF-1 receptor.     

THE PRIMARY VASCULATURE OF CORDAIANTHUS CONCINNUS

The pollen strobilus Cordaianthus concinnus is examined as a possible indicator of the basic pattern of vascular architecture in stems of the Cordaitales. Bract traces arise from two points in the stele of the bilateral primary axis and diverge to the regularly arranged, four-ranked bracts. Tracheids to the axillary secondary shoots arise as two traces that flank the position of bract trace emission. Distally, the secondary shoot traces unite to form a stele that becomes increasingly dissected at successively higher levels. Although radially aligned, these tracheids show thickening patterns on all walls and are not separated by vascular rays; they are therefore interpreted as primary xylem. The traces form sympodia that are similar to those of typical eustelic gymnosperms. Scale traces from the secondary shoots arise by the tangential division of an individual axial bundle and occur in arrangements that range from a ½ to a % spiral. The vascular architecture of these secondary axes is interpreted as the equivalent of that in the stems of extant conifers with spiral phyllotaxis.     

Manual chronostasis: tactile perception precedes physical contact

When saccading to a silent clock, observers sometimes think that the second hand has paused momentarily. This effect has been termed chronostasis and occurs because observers overestimate the time that they have seen the object of an eye movement. They seem to extrapolate its appearance back to just prior to the onset of the saccade rather than the time that it is actually fixated on the retina. Here, we describe a similar effect following an arm movement: subjects overestimate the time that their hand has been in contact with a newly touched object. The illusion's magnitude suggests backward extrapolation of tactile perception to a moment during the preceding reach. The illusion does not occur if the arm movement triggers a change in a continuously visible visual target: the time of onset of the change is estimated correctly. We hypothesize that chronostasis-like effects occur when movement produces uncertainty about the onset of a sensory event. Under these circumstances, the time at which neurons with receptive fields that shift in the temporal vicinity of a movement change their mappings may be used as a time marker for the onset of perceptual properties that are only established later.     

Is Ginkgo biloba (Ginkgoaceae) really an oviparous plant?

Germination of Ginkgo biloba seeds with intact and removed sarcotesta was compared to test the role of the seed coat in germination biology. The presence of an intact sarcotesta significantly reduced total germination percentage when compared to seeds with the sarcotesta removed. Some seeds were also cold stratified. This treatment was not necessary for germination, but it did improve total germination percentage. The seeds were collected during the period of natural abscission. Contrary to the accepted literature, we found that Ginkgo seeds contain well-developed embryos at the time of dispersal. These data demonstrate that the seed coat contributes to winter dormancy of G. biloba, and that the phenology of this species is less primitive than popularly believed.     

The role of comparative morphology and anatomy in interpreting the systematics of fossil gymnosperms

This paper is an analysis of the systematics and phylogeny of gymnosperms as recently proposed by Meyen (Bot. Rev.50(1): 1–111. 1984). Attention is focused on the philosophical approach and on the fundamental concepts that frame the systematic scheme. Morphological interpretations are examined in relation to the concept of homology, and criteria employed for the recognition of whole plants from fossil evidence are evaluated. An examination of fossils from Upper Devonian and Lower Carboniferous strata reveals that only the ovules and ovulate fructifications constitute unequivocal evidence for gymnosperms in these strata. Such examination also reveals that they all can be interpreted as conforming to the same basic structure. If true, there is no evidence for more than one major group of gymnosperms in Devonian and Lower Carboniferous strata. Although many conclusions of Meyen are not accepted, his work plays a valuable role in focusing attention on important, unresolved questions of gymnosperm systematics, and provides a poignant stimulus for the proposal of alternative hypotheses.     

Reduced lipogenesis in cafeteria-fed rats exhibiting diet-induced thermogenesis

Fatty-acid synthesis has been measured in vivo with³H₂O in cafeteria-fed rats exhibiting diet-induced thermogenesis. Synthesis was decreased in brown adipose tissue, the liver, white adipose tissue, and the carcass of the cafeteria-fed animals compared to rats fed the normal stock diet. Whole-body synthesis was also decreased in the cafeteria-fed group. Diet-induced thermogenesis, in contrast to cold-induced non-shivering thermogenesis does not lead to increased fatty-acid synthesis and this is presumably due to the inhibitory effects on lipogenesis of the high dietary fat intake characteristic of cafeteria diets. The results also indicate that the energy cost of body fat deposition in cafeteria-fed rats is lower than in animals fed a low-fat/high-carbohydrate stock diet.     

Infrared Thermography and Ultrasonography to Indirectly Monitor the Influence of Liner Type and Overmilking on Teat Tissue Recovery

Eight Danish Holstein cows were milked with a 1-mm thick specially designed soft liner on their right rear teat and a standard liner mounted under extra high tension on their left rear teat. Four of the animals were overmilked for 5 min. Rear teats were subjected to ultrasound examination on the first day and to infrared thermography on the second day. Teats were submersed in ethanol 20 min post-milking on the second day. Ultrasonography measurements showed that teat canal length increased by 30–41% during milking. Twenty minutes after milking, teats milked with modified standard liners still had elongated teat canals while teats milked with the soft liner were normalized. Overmilking tended to increase teat wall thickness. Approximately 80% of variability in teat canal length, from before teat preparation to after milking, could be explained by changes during teat preparation. Thermography indicated a general drop in teat temperature during teat preparation. Teat temperature increased during milking and continued to increase until the ethanol challenge induced a significant drop. Temperatures approached pre-challenge rather than pre-milking temperatures within 10 minutes after challenge. Teat temperatures were dependent on type of liner. Mid-teat temperatures post-challenge relative to pre-teat preparation were dependent on overmilking. Thermography and ultrasound were considered useful methods to indirectly and non invasively evaluate teat tissue integrity.     

Evolution of body condition‐dependent dispersal in metapopulations

Body condition‐dependent dispersal strategies are common in nature. Although it is obvious that environmental constraints may induce a positive relationship between body condition and dispersal, it is not clear whether positive body conditional dispersal strategies may evolve as a strategy in metapopulations. We have developed an individual‐based simulation model to investigate how body condition–dispersal reaction norms evolve in metapopulations that are characterized by different levels of environmental stochasticity and dispersal mortality. In the model, body condition is related to fecundity and determined either by environmental conditions during juvenile development (adult dispersal) or by those experienced by the mother (natal dispersal). Evolutionarily stable reaction norms strongly depend on metapopulation conditions: positive body condition dependency of dispersal evolved in metapopulation conditions with low levels of dispersal mortality and high levels of environmental stochasticity. Negative body condition‐dependent dispersal evolved in metapopulations with high dispersal mortality and low environmental stochasticity. The latter strategy is responsible for higher dispersal rates under kin competition when dispersal decisions are based on body condition reached at the adult life stage. The evolution of both positive and negative body condition‐dependent dispersal strategies is consequently likely in metapopulations and depends on the prevalent environmental conditions.     

Association of an MHC Class II Haplotype with Increased Risk of Polymyositis in Hungarian Vizsla Dogs

A breed-specific polymyositis is frequently observed in the Hungarian Vizsla. Beneficial clinical response to immunosuppressive therapies has been demonstrated which points to an immune-mediated aetiology. Canine inflammatory myopathies share clinical and histological similarities with the human immune-mediated myopathies. As MHC class II associations have been reported in the human conditions we investigated whether an MHC class II association was present in the canine myopathy seen in this breed. 212 Hungarian Vizsla pedigree dogs were stratified both on disease status and degree of relatedness to an affected dog. This generated a group of 29 cases and 183 “graded” controls: 93 unaffected dogs with a first degree affected relative, 44 unaffected dogs with a second degree affected relative, and 46 unaffected dogs with no known affected relatives. Eleven DLA class II haplotypes were identified, of which, DLA-DRB1*02001/DQA1*00401/DQB1*01303, was at significantly raised frequency in cases compared to controls (OR = 1.92, p = 0.032). When only control dogs with no family history of the disease were compared to cases, the association was further strengthened (OR = 4.08, p = 0.00011). Additionally, a single copy of the risk haplotype was sufficient to increase disease risk, with the risk substantially increasing for homozygotes. There was a trend of increasing frequency of this haplotype with degree of relatedness, indicating low disease penetrance. These findings support the hypothesis of an immune-mediated aetiology for this canine myopathy and give credibility to potentially using the Hungarian Vizsla as a genetic model for comparative studies with human myositis.