Borkhsenius S N, Sergeeva G N
Tsitologiia. 1979 Mar;21(3):327-33.
DNA from Bursaria truncatella was isolated and purified by conventional methods. The DNA base content was calculated from both centrifugation in CsCl and melting. The GC-content is 24%. In CsCl density gradient 3H-DNA is banded as a single peak at a range 1.682--1.688 g/cm3 with the maximum at 1.684 g/cm3. The Tm in 0.12 M FB (pH 6.8) was 79 degrees C. About 50% of DNA seems to be represented by highly repetitive sequences, another 50% being made of single-copy sequences (a preliminary data on DNA-DNA reassotiation kinetics). For the estimation of the molecular weight of DNA, the cells were lysed immediately before the centrifugation, at the surface of the alkaline isokinetic sucrose gradient solution. Two components of DNA were detected with molecular weights 10-10(6) and 100-10(6) daltons. It is likely that these two components belong to the macronuclear DNA, because according to cytophotometrical evidence the DNA content in the macronucleus of B. truncatella is 2500 times as much as that in its micronucleus.
用常规方法分离并纯化了截形扁藻的DNA。通过氯化铯离心和热变性两种方法计算了DNA的碱基含量。GC含量为24%。在氯化铯密度梯度中，3H-DNA在1.682-1.688 g/cm3范围内呈单峰带状分布，最大值在1.684 g/cm3处。在0.12 M FB（pH 6.8）中的熔解温度为79℃。约50%的DNA似乎由高度重复序列组成，另外50%由单拷贝序列组成（关于DNA-DNA复性动力学的初步数据）。为了估计DNA的分子量，在离心前，在碱性等速蔗糖梯度溶液表面立即裂解细胞。检测到DNA的两个组分，分子量分别为10-10(6)和100-10(6)道尔顿。这两个组分可能属于大核DNA，因为根据细胞光度法证据，截形扁藻大核中的DNA含量是其微核中DNA含量的2500倍。
