Das M, Rabinowitch E, Szalay L
Biophys J. 1968 Oct;8(10):1131-7. doi: 10.1016/S0006-3495(68)86544-0.
The change of the quantum yield of fluorescence, Phi, with the frequency of exciting light, was investigated in Chlorella, Anacystis, and Porphyridium suspensions, and in sonicates from these cells prepared under aerobic and anaerobic conditions. In case of Chlorella, sonicates were made in acid and in alkaline media (pH 4.65 and 7.80). In the alkaline medium, a drop of Phi towards the longer waves was found to begin at 1.466 x 10(4) cm(-1) (682 nm) in sonicates, and in suspension. In the acid medium, the drop began at 1.471 x 10(4) cm(-1) (680 nm), 1.418 x 10(4) cm(-1) (705 nm), and 1.389 x 10(4) cm(-1) (720 nm) in suspension, anaerobic sonicate, and aerobic sonicate, respectively. The results indicate that the cause of the change in the red drop is preferential destruction of a long-wave component of chlorophyll a (such as Chl a 693). The amount of this component remaining after sonication is larger in alkaline than in acid sonicates. With Anacystis and Porphyridium, only alkaline suspensions (pH 7.80) could be used for sonication, because in acid medium, the phycobilin-chlorophyll complex is rapidly broken and phycobilin extracted from the cell. In Anacystis, the red drop begins at 1.562 x 10(4) cm(-1) (640 nm) and 1.538 x 10(4) cm(-1) (650 nm) in suspension and sonicate, respectively; in Porphyridium, it starts at 1.550 x 10(4) cm(-1) (645 nm) in both cases. These results suggest that sonication in alkaline medium (pH 7.80) destroys some Chl a 693 in Anacystis, but not in Porphyridium.
在小球藻、集胞藻和紫球藻的悬浮液以及在需氧和厌氧条件下制备的这些细胞的超声提取物中，研究了荧光量子产率（Phi）随激发光频率的变化。对于小球藻，在酸性和碱性介质（pH 4.65和7.80）中制备超声提取物。在碱性介质中，发现在超声提取物和悬浮液中，Phi向较长波长的下降在1.466×10⁴cm⁻¹（682nm）处开始。在酸性介质中，悬浮液、厌氧超声提取物和好氧超声提取物中，下降分别在1.471×10⁴cm⁻¹（680nm）、1.418×10⁴cm⁻¹（705nm）和1.389×10⁴cm⁻¹（720nm）处开始。结果表明，红降变化的原因是叶绿素a的长波成分（如Chl a 693）被优先破坏。超声处理后，碱性超声提取物中该成分剩余量比酸性超声提取物中的大。对于集胞藻和紫球藻，仅碱性悬浮液（pH 7.80）可用于超声处理，因为在酸性介质中，藻胆蛋白 - 叶绿素复合物会迅速分解，藻胆蛋白会从细胞中被提取出来。在集胞藻中，悬浮液和超声提取物中红降分别在1.562×10⁴cm⁻¹（640nm）和1.538×10⁴cm⁻¹（650nm）处开始；在紫球藻中，两种情况下红降均在1.550×10⁴cm⁻¹（645nm）处开始。这些结果表明，在碱性介质（pH 7.80）中进行超声处理会破坏集胞藻中的一些Chl a 693，但不会破坏紫球藻中的Chl a 693。
