The isolation of nucleoli from ungerminated pea embryos

A method is described for the isolation of nuclei and nucleoli from ungerminated pea embryos. Electron micrographs of the nucleolar preparation indicate a high degree of purity but only a partial preservation of composition, because of a loss of material from the nucleoli which occurs during the isolation procedure.     

Distribution of Pirhemocyton Chatton & Blanc and other, Possibly Related, Infections of Poikilotherms

SYNOPSIS. Data for host and geographic distribution are listed for Pirhemocyton and for apparently similar infections of poikilothermic vertebrates. The list was compiled from published accounts of Pirhemocyton, Toddia, Cytamoeba, Bertarellia , Piscine erythrocytic necrosis, Immanoplasma, Haematractidium, Sauroplasma, Sauromella, Serpentoplasma, Tunetella, Haemohormidium and unnamed infections. New records are included for Pirhemocyton and Haematractidium. The probability that some may be viruses and not protozoa is discussed; Haematractidium is shown by electron microscopy to be a eukaryote whereas Immanoplasma is not a eukaryote.     

Species of street tree is important for southern hemisphere bird trophic guilds

Abstract Urban environments are highly modified with unique assemblages of bird species. Much of the research on urban bird assemblages comes from the northern hemisphere. Southern hemisphere bird assemblages differ from northern hemisphere assemblages in that they contain a large proportion of nectarivores. In this study we focus on bird use of street trees in Australia. We investigate the relative influence of tree species (plane tree, Platanus x acerifolia; red gums, Eucalyptus camaldulensis; jacaranda, Jacaranda mimosifolia; bottlebrush, Callistemon citrinus), season and the environment surrounding street trees, on the abundance and species richness of birds in Adelaide, South Australia. Our study considers birds in terms of granivore, nectarivore and insectivore trophic guilds. Nectarivores accounted for the greatest proportion of observations, in terms of abundance, in each of the tree species investigated. Species of street tree was a significant influence on bird use of the trees for all birds and each dietary guild. Red gums were used more than the other tree species by nectarivores, while plane trees were used more than the other trees by insectivores. Use of the tree species by granivores varied with the season. The measures of the environment surrounding street trees were largely unimportant with the exception of traffic for nectarivores in some cases. Urban avifauna use street trees and the species of tree will strongly influence its use by birds. However, the pattern of use of street tree species varied at different times of year and differed between different trophic guilds of birds. The dominance of nectarivores in the southern avifauna will likely produce different patterns of urban environment use to northern hemisphere avifaunas.