4-Fluoro-2-nitro-N-methylanili

Isolation of Mutants and Construction of Intersexual Heterokaryons of Blakeslea trispora

of heterokaryons. Because all life stages are multinucleated, recessive mutants are isolated after exposure to N -methyl-N ′-nitro-N -nitrosoguanidine, a strong mutagen and inactivator of nuclei. Intersexual heterokaryons are obtained easily

Mismatch Repair Assay

as an important route to tolerance of certain cytotoxic methylating agents (reviewed in 4 ). Cell lines that are deficient for methytransferase activity normally exhibit extreme sensitivity to N -methyl-N -nitrosourea (MNU) or 1-methyl-3-nitro-1-nitrosoguanidine

Assay of NOS Activity by the Measurement of Conversion of Oxyhemoglobin to Methemoglobin by NO

such as Nω -nitro-L -arginine (L -NNA) and its methyl ester, L -NAME (3 ,4 ). Using the protocol described, this technique is sensitive (limit of detection approx 20 pmol/min per g tissue), specific for NOS in conjunction with the use of NOS inhibitors