Lepp PW, Schmidt TM
Department of Microbiology, 202 Giltner Hall, Michigan State University, E. Lansing, MI 48824-1101, USA.
Arch Microbiol. 1998 Sep;170(3):201-7. doi: 10.1007/s002030050634.
Light-limited batch cultures of Synechococcus spp. strains PCC 6301 and WH 8103 exhibited a positive correlation between the specific growth rate and the cellular content of both RNA and DNA. The ratio of RNA to DNA increased with the growth rate in Synechococcus sp. strain WH 8103, as it does in heterotrophic bacteria, but remained constant in Synechococcus sp. strain PCC 6301. The cellular content of nucleic acids decreased during light periods and increased during dark periods in Synechococcus sp. strain PCC 6301 entrained by 12-h light/ 12-h dark (diurnal) cycles. This result was unexpected in light of experiments demonstrating a circadian increase in transcriptional activity during the subjective light periods and a decrease in transcriptional activity during subjective dark periods. The cyclical variation in cellular nucleic acid content during diurnal cycles appears to be in part a function of the timing of cell division and will influence estimates of in situ growth rates or relative abundances of cyanobacteria using oligonucleotide probes complementary to 16S rRNA.
聚球藻属菌株PCC 6301和WH 8103的光限制分批培养物中，比生长速率与RNA和DNA的细胞含量之间呈现正相关。在聚球藻属菌株WH 8103中，RNA与DNA的比率随生长速率增加，就像在异养细菌中一样，但在聚球藻属菌株PCC 6301中保持恒定。在由12小时光照/12小时黑暗（昼夜）循环诱导的聚球藻属菌株PCC 6301中，核酸的细胞含量在光照期间减少，在黑暗期间增加。鉴于实验表明在主观光照期间转录活性有昼夜节律性增加，而在主观黑暗期间转录活性降低，这一结果出乎意料。昼夜循环中细胞核酸含量的周期性变化似乎部分是细胞分裂时间的函数，并且会影响使用与16S rRNA互补的寡核苷酸探针来估计蓝细菌的原位生长速率或相对丰度。
