New Type of Papillomavirus and Novel Circular Single Stranded DNA Virus Discovered in Urban Rattus norvegicus Using Circular DNA Enrichment and Metagenomics

Rattus norvegicus (R. norvegicus) are ubiquitous and their presence has several effects on the human populations in our urban areas on a global scale. Both historically and presently, this close interaction has facilitated the dissemination of many pathogens to humans, making screening for potentially zoonotic and emerging viruses in rats highly relevant. We have investigated faecal samples from R. norvegicus collected from urban areas using a protocol based on metagenomic enrichment of circular DNA genomes and subsequent sequencing. We found a new type of papillomavirus, with a L1 region 82% identical to that of the known R. norvegicus Papillomavirus 2. Additionally, we found 20 different circular replication associated protein (Rep)-encoding single stranded DNA (CRESS-DNA) virus-like genomes, one of which has homology to the replication-associated gene of Beak and feather disease virus. Papillomaviruses are a group of viruses known for their carcinogenic potential, and although they are known to infect several different vertebrates, they are mainly studied and characterised in humans. CRESS-DNA viruses are found in many different environments and tissue types. Both papillomaviruses and CRESS-DNA viruses are known to have pathogenic potential and screening for novel and known viruses in R. norvegicus could help identify viruses with pathogenic potential.     

Physiological Responses and Partisan Bias: Beyond Self-Reported Measures of Party Identification

People are biased partisans: they tend to agree with policies from political parties they identify with, independent of policy content. Here, we investigate how physiological reactions to political parties shape bias. Using changes in galvanic skin conductance responses to the visual presentation of party logos, we obtained an implicit and physiological measure of the affective arousal associated with political parties. Subsequently, we exposed subjects to classical party cue experiments where the party sponsors of specific policies were experimentally varied. We found that partisan bias only obtains among those exhibiting a strong physiological reaction to the party source; being a self-reported party identifier is not sufficient on its own. This suggests that partisan bias is rooted in implicit, affective reactions.     

A method to study zhizosphere processes in thin soil layers of different proximity to roots

Frankia is the diverse bacterial genus that fixes nitrogen within root nodules of actinorhizal trees and shrubs. Systematic and ecological studies of Frankia have been hindered by the lack of morphological, biochemical, or other markers to readily distinguish strains. Recently, nucleotide sequence of 16 S RNA from the small ribosomal subunit has been used to classify and identify a variety of microorganisms. We report nucleotide sequences from portions of the 16 S ribosomal RNA from Frankia strains AcnI1 isolated from Alnus viridis ssp. crispa (Ait.) Turrill and PtI1 isolated from Purshia tridentata (Pursh) DC. The number of nucleotide base substitutions and gaps we find more than doubles the previously reported sequence diversity for the same variable regions within other strains of Frankia.     

Observations on the Ecology of Weaver Ants (Oecophylla smaragdina Fabricius) in a Thai Mangrove Ecosystem and Their Effect on Herbivory of Rhizophora mucronata Lam.

Ants of the genus Oecophylla are predators of other insects and are able to protect a variety of terrestrial plants against pest insects; however, observations on the ecology of these ants in mangrove forests are lacking. General observations on the ecology of Oecophylla smaragdina were carried out in a Thai mangrove forest to determine if these ants can protect their host plants in less favorable mangrove habitats. Leaf herbivory and the density of O. smaragdina ants were measured on Rhizophora mucronata trees at two sites. The results showed a negative correlation between ant density and herbivory. At both sites, the mean percent damaged leaf area was more than four times higher on trees without ants compared to “ant‐trees.” A significant negative correlation was found between tree mean percent leaf damage and the density of ants on the tree. Furthermore, on trees with ants, there was less herbivory on leaves close to ant nests compared to other leaves on the tree. Most damage was caused by chrysomelid beetles (62%) and sesarmid crabs (25%) and both types of herbivory were significantly reduced on ant‐trees.     

PHYTOCHROME CONTROL OF ROOT GROWTH RATE IN LEMNA SPECIES

Root growth rate was studied in Lemna gibba L. (strains Gl and G3) and L. minor L. in relation to low energy red and far-red light treatments. Far-red treatments inhibited growth rate; inhibition was abolished upon subsequent treatment with red light. These effects can be observed after an 18-hr growth period. This red/far-red photoreversible response suggests that root growth in L. gibba L. and L. minor L. is under phytochrome control.     

Review

Book reviewed in this article:
Scripta Botanica Belgica volume 1, 199 pages, ed. E. Robberecht. 1992. - Anderson, L., A Provisional Checklist of Neotropical Rubiaceae
Ibid. vol. 2, 153 pages, ed. E. Robberecht. 1992. -Ghanzafar, S. A., An annotated catalogue of the vascular plants of Oman and their vernacular names
Ibid. vol. 3, 376 pages, ed. C. Puff. 1991. - The genus Paederia L. (Rubiaceae-Paedeneae): a multidisciplinary study     

Pathways of carbon cycling in marine surface waters: the fate of small-sized phytoplankton in the Northeast Water Polynya

The fate of small-sized phytoplankton (<5 µm) and pathwaysof carbon cycling in surface waters, i.e. recycling within orexport out of the mixed layer, were investigated in the NortheastWater (NEW) Polynya (77–81°N) from 23 May to 22 July1993. The sampling covered a wide range of ice, hydrographicand nutrient conditions. Chlorophyll a concentrations, phytoplanktonproduction rates and zooplankton abundances were determinedin the field, and potential rates of grazing by protozoa, copepodsand appendicularians were calculated from abundances, usingassumptions from the literature. To our knowledge, this is thefirst published attempt to assess concurrently the grazing ofthese three plankton groups in the Arctic. The production rateof small-sized phytoplankton was significantly higher in ice-freecompared with ice-covered areas, but the biomasses of small-sizedphytoplankton and zooplankton were not. Potential recycling,downward export and horizontal advection of phytoplankton werecalculated by resolving carbon budgets for the mixed layer.A large fraction of the small-sized phytoplankton produced insidethe polynya was advected horizontally to the ice-covered partof the NEW, where these algae were necessary to sustain theheterotrophic community. We conclude that the fate of small-sizedphytoplankton production was mostly recycling (>70%). Downwardexport would have occurred infrequently, as a result of intensegrazing by appendicularians. Size-differential pathways of carboncycling in planktonic food webs are discussed.