Leaf microbodies (peroxisomes) and catalase localization in plants differing in their photosynthetic carbon pathways

Summary Kinetic studies of the uptake of hydroquinone--D-glucoside (arbutin) by excised roots of barley demonstrated that this compound is actively transported. Similar studies on the uptake of hydroquinone indicated that the latter compound enters the root tissues by diffusion. A concentration gradient favouring diffusion is maintained for at least three hours by the conversion of the aglucone to its correspondings glucoside. Hydroquinone, at a concentration of 5 mM, reduced uptake of ⁸⁶rubidium ion by approximately 30%.This work was supported by a grant from the National Research. Council of Canada     

Studies on Chrysophyceae from some ponds and lakes in Alaska

Summary A new variety, Mallomonopsis elliptica var. salina, of M. elliptica var. elliptica Matwienko is described as seen in the living state in the light microscope, and in the electron microscope. The locality in which it was found is described.

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Zusammenfassung Eine neue Varietät, Mallomonopsis elliptica var. salina, von M. elliptica var. elliptica Matwienko wird beschrieben. Sie wurde in lebendiger Gestalt in dem Lichtmikroskop and in dem Elektronenmikroskop beobachtet. Der Fundort wird beschrieben.

     

Seroprevalence of B virus (Herpesvirus simiae) antibodies in a naturally formed group of rhesus macaques

Eighty-two percent of a group of rhesus monkeys removed from Cayo Santiago were seropositive for B virus (Herpesvirus simiae) antibodies. Similar results were obtained from the Cayo Santiago macaque population two decades ago and from feral Indian rhesus monkeys. Thus it is likely that B virus has been enzootic in the Cayo Santiago population since 1938, when the colony was established with stock imported from India.     

A major difference between the divergence patterns within the lines-1 families in mice and voles

L1 retroposons are represented in mice by subfamilies of interspersed sequences of varied abundance. Previous analyses have indicated that subfamilies are generated by duplicative transposition of a small number of members of the L1 family, the progeny of which then become a major component of the murine L1 population, and are not due to any active processes generating homology within preexisting groups of elements in a particular species. In mice, more than a third of the L1 elements belong to a clade that became active approximately 5 Mya and whose elements are > or = 95% identical. We have collected sequence information from 13 L1 elements isolated from two species of voles (Rodentia: Microtinae: Microtus and Arvicola) and have found that divergence within the vole L1 population is quite different from that in mice, in that there is no abundant subfamily of homologous elements. Individual L1 elements from voles are very divergent from one another and belong to a clade that began a period of elevated duplicative transposition approximately 13 Mya. Sequence analyses of portions of these divergent L1 elements (approximately 250 bp each) gave no evidence for concerted evolution having acted on the vole L1 elements since the split of the two vole lineages approximately 3.5 Mya; that is, the observed interspecific divergence (6.7%-24.7%) is not larger than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses showed no clustering into Arvicola and Microtus clades.      

Molecular phylogeny and divergence times of drosophilid species

The phylogenetic relationships and divergence times of 39 drosophilid species were studied by using the coding region of the Adh gene. Four genera--Scaptodrosophila, Zaprionus, Drosophila, and Scaptomyza (from Hawaii)--and three Drosophila subgenera--Drosophila, Engiscaptomyza, and Sophophora--were included. After conducting statistical analyses of the nucleotide sequences of the Adh, Adhr (Adh-related gene), and nuclear rRNA genes and a 905-bp segment of mitochondrial DNA, we used Scaptodrosophila as the outgroup. The phylogenetic tree obtained showed that the first major division of drosophilid species occurs between subgenus Sophophora (genus Drosophila) and the group including subgenera Drosophila and Engiscaptomyza plus the genera Zaprionus and Scaptomyza. Subgenus Sophophora is then divided into D. willistoni and the clade of D. obscura and D. melanogaster species groups. In the other major drosophilid group, Zaprionus first separates from the other species, and then D. immigrans leaves the remaining group of species. This remaining group then splits into the D. repleta group and the Hawaiian drosophilid cluster (Hawaiian Drosophila, Engiscaptomyza, and Scaptomyza). Engiscaptomyza and Scaptomyza are tightly clustered. Each of the D. repleta, D. obscura, and D. melanogaster groups is monophyletic. The splitting of subgenera Drosophila and Sophophora apparently occurred about 40 Mya, whereas the D. repleta group and the Hawaiian drosophilid cluster separated about 32 Mya. By contrast, the splitting of Engiscaptomyza and Scaptomyza occurred only about 11 Mya, suggesting that Scaptomyza experienced a rapid morphological evolution. The D. obscura and D. melanogaster groups apparently diverged about 25 Mya. Many of the D. repleta group species studied here have two functional Adh genes (Adh-1 and Adh-2), and these duplicated genes can be explained by two duplication events.      

Haemorrhagic Septicaemia in the Lamprey Geotria australis Gray

The early upstream migrants of the lamprey, Geotria australis , were occasionally found dead in the field and suffered a very heavy mortality when held in the laboratory. The clinical signs exhibited by dying animals included the production of massive amounts of mucus, petechial haemorrhage of the skin and fins, and both haemorrhage and oedema around the eyes. Necropsy also revealed haemorrhage and oedema in various internal structures and in one case thrombosis and degeneration of blood vessels in the gill. The disease was attributed to infection with Aeromonas hydrophila and Pseudomonas fluorescens which were cultured from the organs of diseased animals. No signs of this disease occurred when the aquaria water was treated with chlortetracycline immediately after the introduction of each new batch of animals.