Morphologic and cytochemical characteristics of blood cells from Hawaiian green turtles.

OBJECTIVE: To identify and characterize blood cells from free-ranging Hawaiian green turtles, Chelonia mydas. SAMPLE POPULATION: 26 green turtles from Puako on the island of Hawaii and Kaneohe Bay on the island of Oahu. PROCEDURE: Blood was examined, using light and electron microscopy and cytochemical stains that included benzidine peroxidase, chloroacetate esterase, alpha naphthyl butyrate esterase, acid phosphatase, Sudan black B, periodic acid-Schiff, and toluidine blue. RESULTS: 6 types of WBC were identified: lymphocytes, monocytes, thrombocytes, heterophils, basophils, and eosinophils (small and large). Morphologic characteristics of mononuclear cells and most granulocytes were similar to those of cells from other reptiles except that green turtles have both large and small eosinophils. CONCLUSIONS: Our classification of green turtle blood cells clarifies improper nomenclature reported previously and provides a reference for future hematologic studies in this species.

Self-assembly of the brain MAP-2 microtubule-binding region into polymeric structures resembling Alzheimer filaments.

The neuronal microtubule-associated protein known as MAP-2 has not been considered to be a subunit of paired helical filaments (PHFs) in neurofibrillary tangles seen in Alzheimer's Disease. We now describe the assembly of paired helical filament-like structures from MAP-2's 203-residue microtubule-binding region (MTBR). SDS gel electrophoresis and equilibrium ultracentrifugation suggest that a dimeric form, cross-linked by an interchain disulfide, is involved in polymerization. MAP-2 MTBR polymers bind thioflavin-S, a dye used to histochemically localize Alzheimer neurofibrillary tangles. Our finding that PHF-like structures assemble from a MAP-2 fragment raises new questions about MAP-2's role in the etiology of Alzheimer's Disease.