Persistence of cadmium-induced adaptive response to genotixicity of maleic hydrazide and methyl mercuric chloride in root meristem cells of Allium cepa L.: Differential inhibition by cycloheximide and buthionine sulfoximine

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• 作者：Panda ; Kamal K. ; Patra ; Jita ; Panda ; Brahma B.
• 关键词：Metallo-adaptive response ; Phytochelatin ; Genotoxicity ; Maleic hydrazide ; Methylmercuric chloride ; Allium MNC assay
• 刊名：Mutation Research/Genetic Toxicology and Environmental Mutagenesis
• 出版年：1997
• 出版时间：March 17, 1997
• 年：1997
• 卷：389
• 期：2-3
• 页码：129-139
• 全文大小：730 K

文摘

With an objective to determine the period of persistence of the metal-induced adaptive response to chemical mutagens and heavy metals, growing root meristems of Allium cepa were conditioned by cadmium sulfate (CdSO₄), 4×10⁻⁷ and 4×10⁻⁶ M for 1 h and subsequently challenged by maleic hydrazide (MH), 5×10⁻³ M or methyl mercuric chloride (MMCl), 1.26×10⁻⁶ M for 3 h at different time intervals ranging from a few minutes to several hours following the conditioning dose. Root meristems, fixed at regular intervals during recovery from 6 to 48 h, were cytologically analysed for cells with micronuclei (MNC). The adaptive responses to MH and MMCl were observed as early as 5 min after the Cd-conditioning that persisted for at least 48 h. Metabolic inhibitors, cycloheximide (CH), 10⁻⁷ M and buthionine sulfoximine (BSO), 10⁻⁴ M administered either prior to or simultaneous with Cd-conditioning effectively prevented the adaptive response to MH. Whereas BSO, an inhibitor of phytochelatin synthesis, prevented the adaptive responses from 15 min to 8 h after the conditioning dose, CH an inhibitor of cytoplasmic protein synthesis prevented the same from 6 to 48 h. The findings underscored the differential roles of phytochelatins and proteins underlying the foregone metallo-adaptive response.