Table II.

The effect of the addition of boric acid on cell rupture and the frequency of single cells and small clusters of C. album cells

Parameter	Boric Acid Concentration
	0 μma	1 μm	2 μm	100 μm
A490b	0.077  ± 0.023	0.039  ± 0.012	0.039  ± 0.011	0.017  ± 0.006
Frequency of particles (% of total particle volume)c
<50 μm (mainly single cells)	11.50  ± 2.46	6.63  ± 0.74	4.60  ± 0.48	4.22  ± 0.64
<100 μm (includes small cluster)	27.68  ± 4.82	16.67  ± 1.85	10.64  ± 0.98	12.68  ± 2.12

Cells were grown continuously in media containing different boric acid concentrations. Cells with 1 and 2 μm boron were previously grown without boron and, before analysis, subcultivated at least five times in media of the given boron concentrations. Cell rupture was estimated by measuring the A₄₉₀ of the medium, and particle size was determined with a laser analyzer.

^a<0.1 μm boric acid. 

^bMean ± sd of at least 10 independent replicates. 

^cCompare Figure 2 (mean ± sd of 10 independent replicates).