Guidelines for the registration of entomogenous fungi as insecticides

Guidelines have been formulated for registration of entomogenous fungi. It is recommended that producers wishing to register a mycoinsecticide supply detailed information concerning the basic biology, host range and characterization of the strain involved as well as details of the manufacturing, quality control, use, field application, efficacy and safety of the pathogen. The recommendations for safety-testing to warm-blooded animals are arranged in a 3-tier system to facilitate decision making for registration authorities. The safety protocols include infection, toxicity, allergenicity and mutagenicity tests. Recommendations are also made to monitor possible effects on people who handle the product during manufacture or application. Information on the activity of the fungus to plants and non-target vertebrates and invertebrates is also required.     

Chondrogenesis of mandibular mesenchyme from the embryonic chick is inhibited by mandibular epithelium and by epidermal growth factor

This study documents the role of mandibular epithelium and epidermal growth factor (EGF) in the initiation, maturation and maintenance of Meckel's cartilage using percent 3H-thymidine-labelled cells as an index of proliferative activity and distribution of labelled cells, chondrocyte size and relative amount of extracellular matrix as indices of chondrogenesis. Mandibular mesenchyme from embryos of H.H. stages 18, 22, 25 was cultured for 2 to 10 days (a) unseparated from mandibular epithelium, (b) in isolation, or (c) after recombination with mandibular epithelium in the presence or absence of 5-40 ng/ml EGF. Epithelium delayed both initiation of chondrogenesis and maturation of already formed cartilage. The 3H-thymidine-labelling index was reduced in cartilage that differentiated in the presence of mandibular epithelium. Epithelium influenced the timing of mesenchymal differentiation (a) by delaying cytodifferentiation through prolonging high levels of proliferation, and (b) by directly affecting differentiation itself. EGF, especially at 10-20 ng/ml, affected both proliferation of mesenchyme and chondrogenesis in mesenchyme cultured with or without epithelium. All observed effects of epithelium on intact tissues could be duplicated by exposing isolated mesenchyme to EGF at 10 ng/ml, i.e. a role for EGF in chondrogenesis is suggested.