Lake snow, caused by the freshwater centric diatom Lindavia intermedia, has become problematic in several large, oligotrophic New Zealand lakes over the past decade. Macroaggregates produced by L. intermedia foul fishing lines, intake screens, and water filters, and have a negative impact on recreational values. It was confirmed that the fibers constituting lake snow are composed of chitin, two chitin synthase genes (chs1 and 2) from L. intermedia were characterized, new qPCR‐based tools to quantify the abundance of the species and measure expression of chs2 relative to the reference gene act1 (the product of which has cytoskeletal functions) were developed. The strong heterogeneity and mucilaginous nature of lake snow samples create particular difficulties for calibrations of gene or transcript copy numbers with cell densities and obtaining high yields of mRNA. However, data collected from four lakes during November 2018 and February and May 2019 show that abundance of L. intermedia is always high when lake snow is also abundant, but that a full range of L. intermedia abundance can occur when lake snow is absent, suggesting that chitin production is not obligate in L. intermedia. This result is consistent with the available data for chs2 expression, which suggest higher transcription when lake snow is abundant. Lake snow production by L. intermedia therefore requires an as yet undetermined stimulus independent of cell abundance.

中文翻译：

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Lindavia intermedia（Bacillariophyceae）和Nuisance湖雪在新西兰：几丁质含量和定量PCR方法估计细胞浓度和几丁质合酶的表达1。

在过去的十年中，由淡水为中心的硅藻Lindavia intermedia引起的湖雪在几个大型贫营养的新西兰湖泊中已成为问题。中间L.粗口钓线，进水口滤网和滤水器产生的大型骨料，对娱乐价值产生负面影响。证实了构成湖雪的纤维是由几丁质组成的，表征了来自中间媒介的两个几丁质合酶基因（chs 1和2），基于新的基于qPCR的工具定量了该物种的丰度并测量了chs 2相对表达参考基因行为开发了1种（具有细胞骨架功能的产品）。湖雪样品的强异质性和粘液性为用细胞密度校准基因或转录本拷贝数以及获得高产量的mRNA带来了特殊的困难。但是，从2018年11月以及2019年2月和2019年5月的四个湖泊收集的数据显示，湖中积雪也很丰富时，中间中间湖的丰度总是很高，但是当湖中不存在下雪时，可能会出现中间湖中的全部丰度，提示中间乳杆菌并非必须产生几丁质。此结果与chs的可用数据一致2表达，表明湖雪丰富时转录更高。因此，由中间乳杆菌产生的湖雪需要与细胞丰度无关的尚未确定的刺激。