A Functional Henipavirus Envelope Glycoprotein Pseudotyped Lentivirus Assay System

<p>Abstract</p> <p>Background</p> <p>Hendra virus (HeV) and Nipah virus (NiV) are newly emerged zoonotic paramyxoviruses discovered during outbreaks in Queensland, Australia in 1994 and peninsular Malaysia in 1998/9 respectively and classified within the new <it>Henipavirus </it>genus. Both viruses can infect a broad range of mammalian species causing severe and often-lethal disease in humans and animals, and repeated outbreaks continue to occur. Extensive laboratory studies on the host cell infection stage of HeV and NiV and the roles of their envelope glycoproteins have been hampered by their highly pathogenic nature and restriction to biosafety level-4 (BSL-4) containment. To circumvent this problem, we have developed a henipavirus envelope glycoprotein pseudotyped lentivirus assay system using either a luciferase gene or green fluorescent protein (GFP) gene encoding human immunodeficiency virus type-1 (HIV-1) genome in conjunction with the HeV and NiV fusion (F) and attachment (G) glycoproteins.</p> <p>Results</p> <p>Functional retrovirus particles pseudotyped with henipavirus F and G glycoproteins displayed proper target cell tropism and entry and infection was dependent on the presence of the HeV and NiV receptors ephrinB2 or B3 on target cells. The functional specificity of the assay was confirmed by the lack of reporter-gene signals when particles bearing either only the F or only G glycoprotein were prepared and assayed. Virus entry could be specifically blocked when infection was carried out in the presence of a fusion inhibiting C-terminal heptad (HR-2) peptide, a well-characterized, cross-reactive, neutralizing human mAb specific for the henipavirus G glycoprotein, and soluble ephrinB2 and B3 receptors. In addition, the utility of the assay was also demonstrated by an examination of the influence of the cytoplasmic tail of F in its fusion activity and incorporation into pseudotyped virus particles by generating and testing a panel of truncation mutants of NiV and HeV F.</p> <p>Conclusions</p> <p>Together, these results demonstrate that a specific henipavirus entry assay has been developed using NiV or HeV F and G glycoprotein pseudotyped reporter-gene encoding retrovirus particles. This assay can be conducted safely under BSL-2 conditions and will be a useful tool for measuring henipavirus entry and studying F and G glycoprotein function in the context of virus entry, as well as in assaying and characterizing neutralizing antibodies and virus entry inhibitors.</p

Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch.

Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A

Volatile exchange between undamaged plants - a new mechanism affecting insect orientation in intercropping

Changes in plant volatile emission can be induced by exposure to volatiles from neighbouring insect-attacked plants.However, plants are also exposed to volatiles from unattacked neighbours, and the consequences of this have not beenexplored. We investigated whether volatile exchange between undamaged plants affects volatile emission and plant-insectinteraction. Consistently greater quantities of two terpenoids were found in the headspace of potato previously exposed tovolatiles from undamaged onion plants identified by mass spectrometry. Using live plants and synthetic blends mimickingexposed and unexposed potato, we tested the olfactory response of winged aphids, Myzus persicae. The altered potatovolatile profile deterred aphids in laboratory experiments. Further, we show that growing potato together with onion in thefield reduces the abundance of winged, host-seeking aphids. Our study broadens the ecological significance of thephenomenon; volatiles carry not only information on whether or not neighbouring plants are under attack, but alsoinformation on the emitter plants themselves. In this way responding plants could obtain information on whether theneighbouring plant is a competitive threat and can accordingly adjust their growth towards it. We interpret this as aresponse in the process of adaptation towards neighbouring plants. Furthermore, these physiological changes in theresponding plants have significant ecological impact, as behaviour of aphids was affected. Since herbivore host plants arepotentially under constant exposure to these volatiles, our study has major implications for the understanding of howmechanisms within plant communities affect insects. This knowledge could be used to improve plant protection andincrease scientific understanding of communication between plants and its impact on other organisms

The decline in joint replacement surgery in rheumatoid arthritis is associated with a concomitant increase in the intensity of anti-rheumatic therapy

BACKGROUND AND PURPOSE: Drug-based treatment of rheumatoid arthritis (RA) has evolved markedly over the past 2 decades. Using nationwide register data, we studied how this has affected the rates of hip, knee, shoulder, and elbow replacement from 1995 to 2010. METHODS: The number of primary joint replacements was obtained from the Finnish Arthroplasty Register. To test the hypothesis that improvements in medical treatment of RA reduce the need for joint replacements, we also collected data about purchases of different disease-modifying anti-rheumatic agents (DMARDs) and biological drugs from the nationwide drug registers. RESULTS: The annual incidence of primary joint replacements for RA declined from 19 per 10(5) in 1995 to 11 per 10(5) in 2010. The decline was greater for upper-limb operations than for lower-limb operations. At the same time, the numbers of individuals using methotrexate, hydroxychloroquine, and sulfasalazine (the most commonly used DMARDs) increased 2- to 4-fold. INTERPRETATION: Our results are in accordance with observations from other countries, and indicate that the use of joint replacements in RA has decreased dramatically. Our data suggest that effective medical therapy is the most likely explanation for this favorable development