Characterization of protective antigens from the midgut of Amblyomma variegatum ticks

Separation of midgut membrane proteins from the tick,Ambylomma variegatum, using a non-ionic detergent (TritonX-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (M_r ∼27,000, 67,000, 86,000 and 95,000,)and 2 proteins (M_r ∼54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins M_r∼27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in nature. In a series of bioassay experiments, rabbits were first immunised with both DET and AQ fractions and then infested with ticks. The egg batch weights of these ticks were reduced by 50% compared to control ticks. Furthermore, there was a significant reduction in the hatchability of eggs laid by ticks fed on rabbits previously immunised with both DET (14%) and AQ (33%) fractions. Based on the egg hatchability, there productive capacity of ticks was reduced by 77 and 48% by DET and AQ fractions, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

PHYTOALEXIN DEFICIENT 4 affects reactive oxygen species metabolism,cell wall and wood properties in hybrid aspen (Populus tremula L. × tremuloides)

The PHYTOALEXIN DEFICIENT 4 (PAD4) gene in Arabidopsis thaliana (AtPAD4) is involved in the regulation of plant – pathogen interactions. The role of PAD4 in woody plants is not known; therefore, we characterized its function in hybrid aspen and its role in reactive oxygen species (ROS)‐dependent signalling and wood development. Three independent transgenic lines with different suppression levels of poplar PAD expression were generated. All these lines displayed deregulated ROS metabolism, which was manifested by an increased H₂O₂ level in the leaves and shoots, and higher activities of manganese superoxide dismutase (MnSOD) and catalase (CAT) in the leaves in comparison to the wild‐type plants. However, no changes in non‐photochemical quenching (NPQ) between the transgenic lines and wild type were observed in the leaves. Moreover, changes in the ROS metabolism in the pad4 transgenic lines positively correlated with wood formation. A higher rate of cell division, decreased tracheid average size and numbers, and increased cell wall thickness were observed. The results presented here suggest that the Populus tremula × tremuloides PAD gene might be involved in the regulation of cellular ROS homeostasis and in the cell division – cell death balance that is associated with wood development.     

The Occurrence and Ape-to-Ape Transmission of the Entodiniomorphid Ciliate Troglodytella abrassarti in Captive Gorillas

ABSTRACT. Entodiniomorphid ciliates are often present in the colons of wild apes. In captive apes the infection tends to gradually disappear, with the exception of Troglodytella abrassarti . We used fecal examinations to screen the gorillas ( Gorilla gorilla gorilla ) in European (Czech Republic, UK) and Australian Zoos to explore the ape-to-ape transmission pattern of T. abrassarti . Gorillas from two out of three European Zoos were positive for T. abrassarti , while gorillas from the Australian Zoo were negative. We documented a horizontal transmission of T. abrassarti to a non-infected adult gorilla introduced into a Troglodytella -positive group in the Prague Zoo and traced the origin of the ciliate infection to the Paignton Zoo (UK) using serial fecal examinations. During this study, two infant gorillas born in the Prague Zoo (CZ) first became positive for T. abrassarti at the age of 9 mo. Ciliate morphology and the sequencing of the small subunit rRNA gene and the internal transcribed spacer rDNA spacer region revealed that T. abrassarti affects both captive gorillas and chimpanzees. We conclude that zoo transport plays a major role in the distribution of T. abrassarti among captive gorillas.     

The Miocene floras of Iceland and their significance for late Cainozoic North Atlantic biogeography

A large number of plant macrofossils from several Middle to Upper Miocene localities from Iceland have been studied. The fossil material includes four ferns and fern allies, seven conifers, and about 40 species of flowering plants. Betula islandica and Salix gruberi are described as new species. Coniferous twigs previously ascribed to the genus Sequoia are shown to belong to Cryptomeria based on macro‐morphological and epidermal features. Fossil plants from Iceland are compared with coeval fossil taxa from Europe and North America and with living plants. The main finding is that the Miocene flora of Iceland belongs to a widespread Neogene northern hemispheric floral type including plants whose representatives are restricted to East Asia, North America and to western Eurasia at the present time. Previously inferred conspicuous similarities to North American modern equivalents appear to be misleading. The type of vegetation in four plant‐bearing sedimentary formations from the late Mid Miocene to Late Miocene, the 12 Ma Brjánslækur‐Seljá Formation, the 10 Ma Tröllatunga‐Gautshamar Formation, the 9–8 Ma Skarðsströnd‐Mókollsdalur Formation, and the 7–6 Ma Hreðavatn‐Stafholt Formation, corresponds to a humid temperate broadleaved (deciduous)–coniferous mixed forest dominated by Betulaceae, Fagaceae and Acer. Changes in species composition in the sedimentary formations reflect a shift from warm temperate (Cfa climate) to cool temperate (Cfb climate) conditions from the late Mid Miocene to the latest Miocene. This shift was connected to repeated phases of extinction and colonization. Specifically, one set of thermophilic taxa including Magnolia, Liriodendron, Sassafras and Comptonia went extinct between 12 and 10 Ma, and appears to have been replaced by another set of thermophilic taxa in the 10 Ma formation (Juglandaceae aff. Pterocarya/Cyclocarya, Rhododendron ponticum type). The 9–8 and 7–6 Ma formations are characterized by taxa that migrated to Iceland from Europe, such as Fagus gussonii, Betula cristata and Pterocarya fraxinifolia type. Although there is convincing evidence that plants colonized Iceland both from North America and Europe until 12 Ma, migration in the younger formations (9–8, 7–6 Ma) is suggested to have occurred mainly from Europe. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149 , 369–417.