TABLE 2.

Microcystin variants from Nostoc sp. strains 152 and IO-102-I^a

Microcystin variant	[M + H]+ (DA)	Rt (min)	Relative amt (%) in Nostoc strains:		Reference
			152	IO-102-I
[DMAdda5]microcystin-LR	981	2.8	<0.5	∼2	42
[ADMAdda5]microcystin-XR	1,077	10.4	0	<10
[ADMAdda5,MeSer7]microcystin-LR	1,041	13.2	<0.5	ND	42
[ADMAdda5]microcystin-XR	1,023	13.7	3	<10
[d-Ser1,ADMAdda5]microcystin-LR	1,039	13.8	<0.5	ND	42
[ADMAdda5]microcystin-LR	1,023	16.1	35	80	42
[ADMAdda5]microcystin-XHar	1,037	17.1	3	ND
[ADMAdda5]microcystin-LHar	1,037	19.6	35	ND	42
[ADMAdda5]microcystin-XR	1,009	23.7	<0.5	ND
[ADMAdda5]microcystin-XR	1,037	25.0	2	∼2
[d-Asp3,ADMAdda5]microcystin-LR	1,009	25.3	10	∼2	42
[ADMAdda5]microcystin-XHar	1,023	27.7	1	ND
[d-Asp3,ADMAdda5]microcystin-LHar	1,023	29.4	10	ND	42

^aProtonated molecular mass ion [M + H]⁺, retention time (R_t), and the relative amounts of the variants detected by LC-UV/MS are given. ND, not detected.