Short Peptide Induces an “Uncultivable” Microorganism To Grow In Vitro

Microorganisms comprise the bulk of biodiversity, but only a small fraction of this diversity grows on artificial media. This phenomenon was noticed almost a century ago, repeatedly confirmed, and termed the “great plate count anomaly.” Advances in microbial cultivation improved microbial recovery but failed to explain why most microbial species do not grow in vitro. Here we show that at least some of such species can form domesticated variants capable of growth on artificial media. We also present evidence that small signaling molecules, such as short peptides, may be essential factors in initiating growth of nongrowing cells. We identified one 5-amino-acid peptide, LQPEV, that at 3.5 nM induces the otherwise “uncultivable” strain Psychrobacter sp. strain MSC33 to grow on standard media. This demonstrates that the restriction preventing microbial in vitro growth may be different from those offered to date to explain the “great plate count anomaly,” such as deficiencies in nutrient composition and concentrations in standard media, medium toxicity, and inappropriate incubation time. Growth induction of MSC33 illustrates that some microorganisms do not grow in vitro because they are removed from their native communities and the signals produced therein. “Uncultivable” species represent the largest source of unexplored biodiversity, and provide remarkable opportunities for both basic and applied research. Access to cultures of some of these species should be possible through identification of the signaling compounds necessary for growth, their addition to standard medium formulations, and eventual domestication.     

“整合物种概念”和“分化路上的物种”

已有的各个物种概念对物种的认识类似盲人摸象, 只包含了物种的某一个方面; 而一个分化后期的成熟物种应涵盖了所有的物种概念。但是, 尚未到达分化后期的物种往往又已开始新一轮的物种分化; 自然中存在的多数“物种”处于分化路上。这种循环往复连续分化产生的物种, 存在种间生殖隔离不彻底、基因流频繁发生、网状进化突出等现象。此外, 对于不同的物种对, 最早开始分化的基因以及不同物种概念所要求的条件的分化顺序不是统一的, 而是随机的。定义一个适合所有“分化路上的物种”概念存在较大困难。但是, 应采用尽可能多的物种概念来界定分化路上的物种、发表新种和进行分类处理; 也应承认种间可能广泛存在不完全的生殖隔离和有限的基因流, 即有不属于两个物种群体的杂交或回交个体的存在。这样划分的物种比只依据一个物种概念认定的物种具有更高的客观性和科学性。     

A “New” low incidence “Hutterite” blood group antigen waldner (Wda)

A “new” red cell antigen has been found so far only in members of Hutterite kindreds with the surname Waldner. The antigen, Wd^a, is inherited as an autosomal dominant and is not part of the ABO, Chido, Colton, Dombrock, Duffy, Kidd, MN, P, or Rh blood group systems.