Detection of conglutinin in bovine serum by complement-dependent agglutination of Escherichia coli

Agglutination of Escherichia coli (ECA) by normal bovine serum was shown to be prevented by heating serum to 56 degrees C for 30 min, but restored by normal horse, swine, rabbit or guinea pig sera. Further investigation of the ECA reaction using techniques to distinguish between conglutination and immunoconglutination indicated ECA to be a conglutination reaction. Testing of 264 sera obtained from 22 normal cattle over a period of 5 months did not show individual or seasonal variation in ECA. Changes in ECA and conglutination were detected in sera of periparturient cows. The ECA reaction is a simple technique for detecting conglutinin in bovine serum.     

Leakage-resistant blood vessels in mice transgenically overexpressing angiopoietin-1

Angiopoietin-1 (Ang1) and vascular endothelial growth factor (VEGF) are endothelial cell-specific growth factors. Direct comparison of transgenic mice overexpressing these factors in the skin revealed that the VEGF-induced blood vessels were leaky, whereas those induced by Ang1 were nonleaky. Moreover, vessels in Ang1-overexpressing mice were resistant to leaks caused by inflammatory agents. Coexpression of Ang1 and VEGF had an additive effect on angiogenesis but resulted in leakage-resistant vessels typical of Ang1. Ang1 therefore may be useful for reducing microvascular leakage in diseases in which the leakage results from chronic inflammation or elevated VEGF and, in combination with VEGF, for promoting growth of nonleaky vessels.     

Combining resistance tomeloidogyne incognita,M. javanica,M. arenaria andPseudomonas solanacearum in potatoes

The objectives of this study were to combine and increase the frequency of resistance to root-knot and bacterial wilt in potatoes.Solanum sparsipilum was used as the source of resistance toMeloidogyne incognita, M. javanica, M. arenaria, andPseudomonas solanacearum. Neo-tuberosum clones into which bacterial wilt resistance fromSolanum phureja had been transferred were also used. It was possible to transfer the resistance to the three species of root-knot fromS. sparsipilum to the Neo-tuberosum population. Two cycles of selection were made and the percentage of clones resistant toP. solanacearum in the last cycle was 16% over the previous cycle. All the clones resistant toM. arenaria were resistant toM. incognita andM. javanica. Two groups of selected clones were formed. Clones in both groups are resistant to root-knot and bacterial wilt. In one of them the two sources of resistance toP. solanacearum have been combined.