A New Saurian Malarial Parasite Plasmodium balli from Panama

SYNOPSIS. Plasmodium balli sp. nov. is described from Anolis lionotus and A. poecilopus of central Panama.
Large, elongate gametocytes and segmenters containing up to 100 merozoites are produced by P. balli. Proerythrocytes and normoblasts are more commonly parasitized than erythrocytes. Pigment is uncommon, but when present consists of a minute dot. Hypertrophy, distortion and lysis of host cell nuclei may result from parasitization of immature blood cells by gametocytes, while enucleated host cells are common.     

The Control of Color in Mammals

SYNOPSIS. Recent advances in the biology of mammalian pigmentationare reviewed.Particular attention is given to emerging informationon the integration of pigmentary events occurring at differentlevels of biological organization within mammalian skin andhair. The structural and functional significance of keratinocytesand melanocytes as components of mammalian epidermal melaninunits is viewed from this perspective. New evidence on the natureof genetic, developmental, endocrine, and radiation influenceson performance of melanocytes and the establishment of pigmentarypatterns is summarized.     

Differentiating Type i and Type ii Alveolar Cells in Rat Lung by OsO4NaI Staining

The fixing-staining mixture consisted of 1 part of 2% aqueous OsO₄ and 3 parts of 3% Nal in distilled water. Fresh lungs were cut into 2 mm slices and immersed in this solution for 24 hr at room temperature. Controls were fixed in buffered OsO₄ alone. Selective staining of type II alveolar cells was shown by the OsO_t-NaI mixture but was absent in the controls. No additional staining of the sections was required, and the selectivity was readily observable in either paraffin or Araldite sections by light microscopy and in Araldite sections by electron microscopy     

Saurian Malarial Parasites in Eastern Panama

SYNOPSIS Plasmodium gonatodi sp. nov. is described from Gonatodes albogularis fuscus of eastern Panama. It is characterized by elongate gametocytes and polymorphic schizonts containing 12-46 nuclei when apparently mature. Both proerythrocytes and erythrocytes are commonly parasitized, host cells are hypertrophied and distorted, and their nuclei are displaced. Prematuration sexual stages may be irregularly shaped and larger than mature gametocytes.
Plasmodium diploglossi Aragão and Neiva , 1909 is reported from Mabuya mabouya in eastern Panama, and Plasmodium morulum sp. nov. is described from this host. P. morulum usually parasitizes immature erythrocytes, and is characterized by lenticular or oval to round gametocytes, and schizonts with 14-40 nuclei usually arranged in a globular mass. Host cells are slightly hypertrophied and distorted, and their nuclei are usually displaced. Inoculation of infected blood into clean hosts produces numerous schizonts in white cells as well as in the erythrocyte series.
Pigment in both P. gonatodi and P. morulum , if present, consists of a few minute dark dots which do not meet the polarized light test for hemozoin.     

Tryptophan Synthetic Pathway and Its Regulation in Chromobacterium violaceum

Extracts of Chromobacterium violaceum catalyzed all of the reactions involved in synthesizing tryptophan from chorismic acid. Tryptophan auxotrophs which had lost any of these activities did not produce the characteristic purple pigment, violacein, when grown on a medium in which tryptophan was limiting. Gel filtration of extracts allowed us to estimate molecular weights for the tryptophan enzymes. All of the enzymes appeared to have molecular weights below 100,000. No enzymes were observed to occur in aggregates. The specific activities of the enzymes of the tryptophan pathway did not change when mutants were grown under conditions of limiting or excess tryptophan. The first enzyme in the pathway, anthranilate synthetase, was subject to feedback control by the end product, tryptophan. Tryptophan acted as a noncompetitive inhibitor with respect to glutamine, one of the substrates for anthranilate synthetase, and as a competitive inhibitor of the reaction when chorismate, the other substrate, was varied. The nonlinearity observed in the Lineweaver-Burk plot in the latter case suggests that there may be more than one chorismate-binding site on anthranilate synthetase.