Johnson T B, Strobel G A
Department of Botany and Microbiology, Montana State University, Bozeman, Montana 59715.
Plant Physiol. 1970 Jun;45(6):761-4. doi: 10.1104/pp.45.6.761.
Corynebacterium sepedonicum produces an extracellular phytotoxic glycopeptide that possesses a capacity to wilt plant cuttings. It has been previously demonstrated that the integrity of some of the membranes of the host cells is destroyed, suggesting the possibility that a biologically active site is present on the toxin molecule. The toxin was chemically altered in the following ways and then tested for biological activity: (a) the NH(2)-terminal group on the peptide portion of the toxin was blocked by the dansylation technique; (b) the OH groups on the sugar and amino acid residues as well as the NH groups on the amino acid residues were blocked by exhaustive methylation; (c) the COO(-) groups were converted to their respective methyl esters; (d) the peptide moiety was removed by pronase digestion. Experimental results indicate that the carboxyl groups of the nonpeptide portion of the molecule are responsible for the biological activity of the toxin. Other experiments showed that the toxin does not affect the membranes of animal cells.The biological activity of the glycopeptide, as well as its chemically altered derivatives, was determined by an instrument designated as a wilt-o-meter that quantitatively measures the strength of plant cuttings. A description of this instrument, how it is used, and how it can be manufactured is also included in this report.
马铃薯环腐棒杆菌产生一种细胞外植物毒性糖肽，它具有使植物插条枯萎的能力。先前已经证明宿主细胞的一些膜的完整性被破坏，这表明毒素分子上可能存在生物活性位点。毒素通过以下方式进行化学改变，然后测试其生物活性：(a)毒素肽部分的NH(2)-末端基团通过丹磺酰化技术被封闭；(b)糖和氨基酸残基上的OH基团以及氨基酸残基上的NH基团通过彻底甲基化被封闭；(c)COO(-)基团被转化为它们各自的甲酯；(d)肽部分通过链霉蛋白酶消化被去除。实验结果表明，分子非肽部分的羧基负责毒素的生物活性。其他实验表明，该毒素不影响动物细胞的膜。糖肽及其化学改变的衍生物的生物活性通过一种称为枯萎测量仪的仪器来测定，该仪器定量测量植物插条的强度。本报告还包括该仪器的描述、其使用方法以及如何制造。
