Pawelczyk S, Bumann D, Abraham W-R
Helmholtz Center for Infection Research, Chemical Microbiology, Braunschweig, Germany.
J Appl Microbiol. 2011 Apr;110(4):1065-73. doi: 10.1111/j.1365-2672.2011.04964.x. Epub 2011 Feb 25.
To determine the kinetics of substrate fluxes in a microbial community in order to elucidate the roles of the community members.
The kinetics of substrate sharing in a bacterial consortium were measured by a new analytical approach combining immunostaining, stable isotope probing and fluorescence-activated cell sorting (FACS). The bacterial consortium, consisting of four strains and growing on 4-chlorosalicylate (4-CS), was pulse-dosed with the degradation intermediate [U-(13) C]-4-chlorocatechol (4-CC). Cells were stained with strain-specific antibodies sorted by FACS and the (13) C-incorporation into fatty acids of the two most abundant members of the community was determined by isotope ratio mass spectrometry. From the two most abundant strains, the primary degrader Pseudomonas reinekei MT1 incorporated the labelled substrate faster than strain Achromobacter spanius MT3 but the maximal incorporation in strain MT3 was almost three times higher than in MT1.
It has been reported that strain MT1 produces 4-CC as an intermediate but has a lower LD50 for it than strain MT3; therefore, MT3 still degrades 4-CC when the concentrations of 4-CC are already too toxic, even lethal, for MT1. By degrading 4-CC, produced by MT1, MT3 protects the entire community against this toxin. The higher affinity but lower tolerance of strain MT1 for 4-chlorocatechol compared to strain MT3 explains the complementary function these two strains have in the consortium adding exceptional stability to the entire community.
The novel approach can reveal carbon fluxes in microbial communities generating quantitative data for systems biology of the microbial community.
确定微生物群落中底物通量的动力学，以阐明群落成员的作用。
通过一种结合免疫染色、稳定同位素探测和荧光激活细胞分选（FACS）的新分析方法，测量了细菌聚生体中底物共享的动力学。该细菌聚生体由四个菌株组成，以4-氯水杨酸（4-CS）为生长底物，向其中脉冲添加降解中间体[U-(13)C]-4-氯邻苯二酚（4-CC）。用菌株特异性抗体对细胞进行染色，通过FACS进行分选，并通过同位素比率质谱法测定群落中两个最丰富成员的脂肪酸中(13)C的掺入情况。在两个最丰富的菌株中，主要降解菌雷氏假单胞菌MT1比西班牙无色杆菌MT3更快地掺入标记底物，但MT3菌株中的最大掺入量几乎是MT1的三倍。
据报道，MT1菌株产生4-CC作为中间体，但其对4-CC的半数致死剂量低于MT3菌株；因此，当4-CC的浓度对MT1已经毒性太大甚至致命时，MT3仍能降解4-CC。通过降解MT1产生的4-CC，MT3保护整个群落免受这种毒素的侵害。与MT3菌株相比，MT1菌株对4-氯邻苯二酚具有更高的亲和力但更低的耐受性，这解释了这两个菌株在聚生体中的互补功能，为整个群落增添了非凡的稳定性。
这种新方法可以揭示微生物群落中的碳通量，为微生物群落的系统生物学产生定量数据。
