Nucleosides with self-complementary hydrogen-bonding motifs: synthesis and base-pairing studies of two nucleosides containing the imidazo[4,5-d]pyridazine ring system.

Synthesis and base-pairing studies of two 2'-deoxyribonucleosides, containing a common heterocyclic base, 7(4)-amino-5(6)H-imidazo[4,5-d]pyridazin-4(7)one (1 and 2), have been reported. The synthesis was accomplished by base-promoted deoxyribosylation of ethyl 5(4)-cyanoimidazole-4(5)-carboxylate (6), followed by ring-closure with hydrazine hydrate. The 1H NMR-based base-pair studies were conducted using DMF-d7 as a solvent by measuring changes in chemical shifts of the amino, hydrazide, imidazole H-2, and the sugar H-1' protons of the nucleosides with variations in concentrations and temperatures.

Broad spectrum antimicrobial activity of leukocyte extracts from the American alligator (Alligator mississippiensis).

Leukocytes were isolated from whole blood of wild alligators by differential sedimentation. The leukocytes were disrupted in 5% AcOH and the crude extracts processed by ultrafiltration. The extracts were subjected to solvent exchange (0.

Antiviral activity of serum from the American alligator (Alligator mississippiensis).

Serum from wild alligators was collected and tested for antibiotic activity against three enveloped viruses using cell-based assays. Alligator serum demonstrated antiviral activities against human immunodeficiency virus type 1 (HIV-1; IC50=0.9%), West Nile virus (WNV; IC50=4.