Cryostat Microtomy of Lung Tissue in an Expanded State

A technique is reported for cryostat sectioning of lung tissue in an expanded state for use in viral immunofluorescence studies. A 1: 2 mixture of O.C.T. embedding compound and phosphate-buffered saline is injected intratracheally into fresh lung tissne. The lung tissue is frozen in liquid nitrogen and sectioned with a cryostat. Compared to other published reports of lung sectioning for immunofluorescence miscroscopy, this method has the advantages of bekg easy and quick, maintaining the lung sectiom in an expanded rather than collapsed state and avoiding contact with chemicals potentially capable of altering sensitive viral antigens.     

The phylogeny of the ant tribe Formicini (Hymenoptera: Formicidae) with the description of a new genus

Abstract. The holarctic ant tribe Formicini is revised, the new genus Bajcaridris described, and possible phylogenetic relationships are discussed. The subgenus Iberoformica is synonymized with Formica. A synopsis, diagnosis and keys to the genera are provided.     

POLYOL DEHYDROGENASE: PURIFICATION. EVIDENCE FOR MULTIPLE FORMS AND SOME PROPERTIES OF THE DOMINANT VARIANT OF THE HORSE LIVER ENZYME

Purification of horse-liver polyoi dehydrogenase (PDH) on DE52 anion-exchange cellulose reveals the presence of three fractions with enzyme activity. These appear in the breakthrough volume (PDH-3) and the salt gradient (PDH-1, -2) respectively. The major band of activity (< 90%) is found in the PDH-2 fraction. A reexamination of sheep-liver polyol dehydrogenase also reveals the presence of three bands of activity, with the dominant fraction (PDH-3) corresponding to the preparation described by Smith (Biochem. J., 83, 135–144, (1962))³. The interaction between horse-liver (and sheep-liver) PDH and Blue Sepharose CL-6B is found to be endothermic. This property is utilized in the final purification step. Horse-liver PDH-2 has a molecular/subunit weight of 85, 000/28, 000, a Stokes' radius of 3.8 nm, and an isoelectric point of 7.4.