Applied Microbiology and Biotechnology Laboratory, Department of Botany, University of Delhi, Delhi, 110 007 India.
Indian J Microbiol. 2007 Mar;47(1):81-5. doi: 10.1007/s12088-007-0015-9. Epub 2007 Jun 14.
In the wild type strain (stock no. 1227) of Thermoactinomyces vulgaris, as reported earlier [Sinha and Singh (1980) Biochem. J. 190, 457-460], all phosphatase isoenzymes (three alkaline - AlpI, AlpII and AlpIII, and one acidic - Acp) are present. However, the auxotrophic mutants, the strains 1286 (thi(-)), 1279 (nic(-), ura(-)) and 1278 (thi(-), ura(-)) exhibited two alkaline phosphatase isoenzymes (AlpII and AlpIII), but AlpI was lacking. In the strain 1261 (nic(-), thi(-)), only AlpIII was expressed, and AlpI and AlpII isoenzymes were missing. The results suggest that the strains, which require either thiamine (1286 and 1278) or nicotinamide (1279) for their growth, were AlpI(-) mutants; and the strain (1261), which requires both thiamine and nicotinamide for its growth, was AlpI(-)/AlpII(-) double mutant. There was no direct correlation between uracil auxotrophy and the expression of phosphatases. The uniform expression of AlpIII and Acp in all the strains, irrespective of their nutrient requirements, suggest that these constitutive phosphatases are species-specific. The specific activities of the thermophilic acid and alkaline phosphatases were maximum in the wild type strain (1227) of T. vulgaris. The next in phosphatase activity was the strain 1279 (an AlpI(-) mutant), followed by their decrease, in order, in the strains 1286 and 1278 (which were also AlpI(-) mutants); while least activity of these enzymes was observed in the obligate thermophile strain 1261 (AlpI(-)/AlpII(-) double mutant).
在先前报道的嗜热放线菌野生型菌株（编号 1227）中，存在所有磷酸酶同工酶（三种碱性- AlpI、AlpII 和 AlpIII，一种酸性- Acp）[Sinha 和 Singh（1980）生物化学杂志。190,457-460]。然而，营养缺陷型突变株，菌株 1286（硫(-)）、1279（尼克酸(-)、尿嘧啶(-)）和 1278（硫(-)、尿嘧啶(-)）表现出两种碱性磷酸酶同工酶（AlpII 和 AlpIII），但缺少 AlpI。在菌株 1261（尼克酸(-)、硫(-)）中，仅表达 AlpIII，缺少 AlpI 和 AlpII 同工酶。结果表明，需要硫胺素（1286 和 1278）或尼克酰胺（1279）生长的菌株为 AlpI(-)突变株；需要硫胺素和尼克酰胺生长的菌株（1261）为 AlpI(-)/AlpII(-)双突变株。尿嘧啶营养缺陷与磷酸酶的表达之间没有直接相关性。所有菌株中 AlpIII 和 Acp 的均匀表达，与其营养需求无关，表明这些组成型磷酸酶是种特异性的。嗜热酸性和碱性磷酸酶的比活性在野生型菌株（1227）中最高。其次是磷酸酶活性的菌株 1279（AlpI(-)突变株），随后依次减少，在菌株 1286 和 1278（也是 AlpI(-)突变株）中；而这些酶的活性最低的是必需嗜热菌株 1261（AlpI(-)/AlpII(-)双突变株）。
