Abstract Violet and purple bacterial pigmentations are uncommon when considering strict aerobes. Here we report discovery of two novel isolates, P102 and P117 from the freshwater Lake Winnipeg, each with violet to deep purple colony colouration. The relationship between pigment production and growth was investigated under different conditions, including a variety of carbon sources, pH, and temperatures. The violet compounds were purified using polar organic solvents, and then structurally characterized via mass spectrometry and nuclear magnetic resonance to be violacein and deoxyviolacein. Strain P117 produced higher concentrations of the darker pigment deoxyviolacein, which resulted in a deeper hue of violet than in cultures of P102. Strain P102, synthesized violacein maximally in liquid rich organic medium at pH 8 and 20 °C, and had 99.3% sequence similarity to the 16S rDNA from Janthinobacterium lividum. Strain P117, related to Massilia violaceinigra sharing 99.2% 16S rDNA sequence similarity, also produced violacein at similar optimal conditions, but developed higher concentrations of pigment at 15 °C. Culture-based methods found that violacein producers composed 0.001% or 0.023% CFU of environmental heterotrophic populations using BG-11 and potato-based media, respectively. Culture-independent high-throughput ribosomal 16S V4 sequencing of environmental DNA was used to detect Gram-negative species known for their production of violacein. Of all bacterial and archaeal sequences present during the fall in littoral waters and sediment of Lake Winnipeg, 5.5% and 6.3%, respectively, belonged to species that have similar pigment, demonstrating the scarcity of violacein producers in this aquatic freshwater system.

中文翻译：

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从加拿大温尼伯湖分离的嗜冷紫罗兰素产生菌

摘要 考虑到严格的需氧菌，紫色和紫色细菌色素沉着并不常见。在这里，我们报告了从温尼伯淡水湖中发现的两个新分离株 P102 和 P117，每个分离株都有紫色到深紫色的菌落颜色。在不同条件下研究了色素产生与生长之间的关系，包括各种碳源、pH 值和温度。使用极性有机溶剂纯化紫色化合物，然后通过质谱和核磁共振进行结构表征，为紫罗兰素和脱氧紫罗兰素。菌株 P117 产生更高浓度的深色色素脱氧紫罗兰素，这导致比 P102 培养物中更深的紫色色调。菌株 P102，在 pH 8 和 20 °C 的富含液体的有机介质中最大程度地合成紫罗兰素，并且具有 99。与来自 Janthinobacterium lividum 的 16S rDNA 的序列相似性为 3%。菌株 P117 与 Massilia violaceinigra 相关，具有 99.2% 的 16S rDNA 序列相似性，也在类似的最佳条件下产生紫罗兰素，但在 15 °C 下产生更高浓度的色素。基于培养的方法发现，使用 BG-11 和基于马铃薯的培养基，紫罗兰素生产者分别占环境异养种群的 0.001% 或 0.023% CFU。环境 DNA 的不依赖培养的高通量核糖体 16S V4 测序用于检测以产生紫罗兰素而闻名的革兰氏阴性物种。在秋季温尼伯湖沿岸水域和沉积物中存在的所有细菌和古菌序列中，分别有 5.5% 和 6.3% 属于具有相似色素的物种，