Heparin-binding growth-associated molecule (HB-GAM) is an extracellular matrix-associated protein implicated in the development and plasticity of neuronal connections of brain. Binding to cell surface heparan sulfate is indispensable for the biological activity of HB-GAM. In the present paper we have studied the structure of recombinant HB-GAM using heteronuclear NMR. These studies show that HB-GAM contains two ␤-sheet domains connected by a flexible linker. Both of these domains contain three antiparallel ␤-strands. In addition to this domain structure, HB-GAM contains the Nand C-terminal lysine-rich sequences that lack a detectable structure and appear to form random coils. Studies using CD and NMR spectroscopy suggest that HB-GAM undergoes a conformational change upon binding to heparin, and that the binding occurs primarily to the ␤-sheet domains of the protein. Search of sequence data bases shows that the ␤-sheet domains of HB-GAM are homologous to the thrombospondin type I repeat (TSR). Sequence comparisions show that the ␤-sheet structures found previously in midkine, a protein homologous with HB-GAM, also correspond to the TSR motif. We suggest that the TSR sequence motif found in various extracellular proteins defines a ␤-sheet structure similar to that found in HB-GAM and midkine. In addition to the apparent structural similarity, a similarity in biological functions is suggested by the occurrence of the TSR sequence motif in a wide variety of proteins that mediate cell-to-extracellular matrix and cell-to-cell interactions, in which the TSR domain mediates specific cell surface binding.Heparin-binding growth-associated molecule (HB-GAM) 1 (p18) was originally isolated from rat brain as an 18-kDa neurite outgrowth-promoting protein, the expression of which in brain tissue peaks during the perinatal stage of rapid axon growth and synapse formation (1). HB-GAM is highly homologous with the midkine (MK) sequence (2-4), and these proteins thus form a two-member family of small extracellular proteins that are conserved in vertebrates.In developing tissues HB-GAM associates with extracellular matrix of axonal tracts and of synapses (5, 6). It is also clearly expressed in developing basement membranes outside of brain (7) and in the cartilage matrix (8). N-syndecan (syndecan-3) acts as a receptor of HB-GAM in brain neurons in vitro (9) and localizes in many anatomical areas to the same developing fiber tracts as HB-GAM (10, 11). The heparan sulfate structure of brain N-syndecan is exceptionally heparin-like, especially in its high content of 2-0-sulfo-iduronic acid residues, which is of importance in the HB-GAM binding carbohydrate epitope, the minimal size of which appears to be 10 monosaccharide residues (12). The neurite outgrowth-promoting effect, based on HB-GAM/N-syndecan interaction, was very recently shown to be mediated by the cortactin/src-kinase signaling pathway to the cytoskeleton of neurites (13). These findings have led to the concept that N-syndecan mediates HB-GAM-induced neurite growth (for r...

The effectiveness of a powdery preparation of a Streptomyces sp. isolate as a seed dressing agent against seed-borne Alternaria brassicicola on different Brassica species was investigated in the study. The preparation was made by freeze-drying and milling the biomass produced in a fermentor into a form suitable for use as a dusting agent. Seed dressing was 80—90 % successful in controlling damping-off from seeds artificially infected with A. brassicicola. The effectiveness of dressing remained unchanged on seeds stored under dry conditions for 5—6 weeks, but subsequently decreased slowly and was ca. 50 % six months after dusting. Streptomyces dressing controlled, in a manner comparable to chemical dressing with thiram, damping-off caused by Alternaria fungi on seedlings which were grown from commercial seed lots of different origin. The results of biological control of damping-off did not vary in the peat lots of different origin whose natural disease suppressivity varied considerably. The control result was the same or better than chemical dressing with thiram. The acidity of the substrate (pH 4.8—8.6) had no effect on the effectiveness of biological control. The results obtained against Alternaria damping-off were the same in other substrates clay, fine sand and mull as in peat.

Disease infection in relation to sowing time of winter rye (Secale cereale) was studied in southern Finland in order to compare overwintering capacity of modern rye varieties and to give recommendations for rye cultivation. This was done by using three sowing times and four rye varieties in field trials conducted at three locations in 1999-2001. The early sown rye (beginning of August) was severely affected by diseases caused by Puccinia recondita and Microdochium nivale, whereas postponing sowing for two weeks after the recommended sowing time resulted in considerably less infection. The infection levels of diseases differed among rye varieties. Finnish rye varieties Anna and Bor 7068 were more resistant to snow mould and more winter hardy than the Polish variety Amilo, or the German hybrid varieties Picasso and Esprit. However, Amilo was the most resistant to leaf rust. In the first year snow mould appeared to be the primary cause of winter damage, but in the second year the winter damage was positively correlated with leaf rust. No significant correlation between frit fly infestation and winter damage or disease incidence of snow mould or leaf rust was established. The late sowing of rye (in the beginning of September) is recommended in Finland, particularly with hybrid varieties, to minimize the need for chemical plant protection in autumn.

The effect of seed dressing with the antagonist Streptomyces griseoviridis on root rots and yields of wheat and barley was studied in field experiments. In long-term field experiments, where different levels of soil-borne inoculum of root rots were maintained with different crop sequences, seed treatment with the antagonist increased yields slightly on average over all experimental years. However, variations between years, crops and crop sequences were considerable. The highest yield increases were in excess of 600 kg/ha, whilst treatment occasionally resulted in slight yield losses. In experiments in which seed naturally infested with Fusarium spp. was used, seed treatment with S. griseoviridis increased yields of wheat but not those of barley. Seed dressing with an organomercurial fungicide resulted in higher yield increases than the biopreparate.

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