Unusual filamentous virus-like particles in symptomless blackberry associated with severe leaf curling in the virus indicator Rubus macraei, and anomalous data using a degenerate badnavirus primer in PCR of Rubus species

Electron microscopy of ultrathin sections of leaves of symptomless Himalaya Giant blackberry and of the virus indicator species, Rubus macraei, showing severe leaf curl symptoms following graft inoculation with scions from this blackberry, detected highly flexuous virus‐like particles with an unusual ‘beaded’ structure. Such particles were restricted to a few vascular cells and were distinct from P‐protein common in some such cells. This virus, provisionally named Hawaiian rubus leaf curl virus (HRLCV), symptomlessly infected a wide range of Rubus species and cultivars. Badnavirus‐like bacilliform particles were observed in some cells of a single R. macraei plant showing leaf curl symptoms following graft inoculation with the causal agent of this disease symptom from Himalaya Giant blackberry after passage through red raspberry, but not in any other material. PCR with primer sets for the badnaviruses Rubus yellow net virus and Gooseberry veinbanding associated virus, showed that no Rubus sources studied contained these viruses. However, using a sequence‐specific primer set designed from the sequence of the product generated with a badnavirus degenerate primer set, a specific product was amplified from healthy plants of all of 16 raspberry cultivars and two Rubus species, but not from 16 blackberry cultivars (including cv. Himalaya Giant). All of these sources were free from viruses known to occur in Rubus. Sequence analysis of this product showed no homology with any known badnavirus, or with any other published sequences. It seems most likely therefore that a region of the raspberry genome has been amplified using the degenerate badnavirus primer set and that it is absent from the blackberry genome.     

Interactions between dung beetles (Coleoptera: Scarabaeidae) and the arbovirus vector Culicoides brevitarsis Kieffer (Diptera: Ceratopogonidae)

Abstract  The potential for dung beetles to reduce populations of the biting midge and arbovirus vector Culicoides brevitarsis in bovine dung was studied in the Hunter Valley, New South Wales (NSW) between 1999 and 2003 using natural populations of insects. Preliminary work to develop experimental procedures showed that: a few C. brevitarsis could survive in buried dung; dung beetles and C. brevitarsis coming to dung were unaffected by a background of shade-cloth used experimentally to prevent dung burial; the most abundant dung beetle, Onthophagus gazella L. and C. brevitarsis oviposition occurred concurrently in the first 2 d after dung deposition, and the potential for interaction between dung beetles and C. brevitarsis was greatest in open pasture adjacent to trees where cattle congregate at night. Laboratory experiments on dung burial showed that C. brevitarsis numbers decreased as numbers of dung beetles increased or as the dry weight of dung decreased due to burial. This was seldom reflected in the field where, although significant burial occurred experimentally in 9 of 20 trials over 3 years, a significant decline in C. brevitarsis numbers attributable to burial only occurred once. C. brevitarsis numbers in the field were lower in unburied dung in 70% of trials. Differences were significant twice and were considered the result of dung disturbance. In the laboratory, decreasing numbers of C. brevitarsis were related to three characteristics of disturbance: the flattening, spreading and reduction in wet weight of the dung. Evidence of C. brevitarsis activity throughout coastal NSW suggests that, while C. brevitarsis numbers may be modified by dung beetles, the interaction is insufficient to prevent their increase, spread and ability to transmit viruses to livestock.     

Experimental stress in inflammatory rheumatic diseases: a review of psychophysiological stress responses

Introduction  

Stressful events are thought to contribute to the aetiology, maintenance and exacerbation of rheumatic diseases. Given the growing interest in acute stress responses and disease, this review investigates the impact of real-life experimental psychosocial, cognitive, exercise and sensory stressors on autonomic, neuroendocrine and immune function in patients with inflammatory rheumatic diseases.     

Relationships between the lucerne flea, Sminthurus viridis (L.) (Collembola: Sminthuridae), and damage to lucerne

Abstract The effect of lucerne flea, Sminthurus viridis , on plant growth (stem length and leaf number) and damage (percentage of leaves damaged and the percentage reduction in leaf area in the top, mid and lower thirds of stems) was considered at 2-weekly intervals in three consecutive lucerne growth cycles, each with a different mode of attack. The data were analysed to progressively determine relationships leading to a proposal for plant-based thresholds for lucerne flea control. Lucerne flea affected each factor measured, with damage considered more appropriate for making control decisions than plant growth. Damage increased from the base of plants upwards and its effect on yield was carried over into subsequent growth cycles. Damage was significantly related to lucerne flea numbers ( P  < 0.001) in two growth cycles and was higher when large nymphs or adults were dominant in one of these cycles. Yield was closely and best related to the percentage of the total number of leaves damaged ( R ² = 81.3%). The percentage of leaves damaged was also related to loss of final yield estimated at 2 ( R ² = 81.3%), 4 ( R ² = 78.9%) and 6 ( R ² = 66.6%) weeks into the first growth cycle only. Direct damage in the other two cycles did not result in yield loss. The percentage of leaves damaged (± confidence intervals) equating to 5% increments in yield loss were estimated at 2, 4 and 6 weeks into the first growth cycle. These are proposed as damage or treatment thresholds for testing.     

Effect of sex and bright coloration on survival and predator‐induced wing damage in an aposematic lantern fly with startle display

1. Aposematic coloration in prey promotes its survival by conspicuously advertising unpalatability to predators. Although classical examples of aposematic signals involve constant presentation of a signal at a distance, some animals suddenly display warning colours only when they are attacked. 2. Characteristics of body parts suddenly displayed, such as conspicuous coloration or eyespot pattern, may increase the survival of the prey by startling the predator, and/or by signalling unpalatability to the predators at the moment of attack. 3. The adaptive value of such colour patterns suddenly displayed by unpalatable prey has not been studied. We experimentally blackened the red patch in the conspicuous red–white–black hindwing pattern displayed by an unpalatable insect Lycorma delicatula White (Hemiptera: Fulgoridae) in response to predator's attack. 4. There was no evidence that the presence of the red patch increased prey survival over several weeks. We hypothesise that predators generalised from the red–white–black patches on the hindwings of unpalatable L. delicatula to any similar wing display as a signal of unpalatability. Because a higher proportion of males than females stay put at their resting sites, displaying their wings in response to repeated attacks by predators, wing damage was more frequent in males than in females. 5. To our knowledge, this is the first experimental test of an adaptive role of aposematic signals presented by unpalatable prey during sudden displays triggered by direct predatory attack.     

Effect of self-association on the structural organization of partially folded proteins: inactivated actin

The propensity to associate or aggregate is one of the characteristic properties of many nonnative proteins. The aggregation of proteins is responsible for a number of human diseases and is a significant problem in biotechnology. Despite this, little is currently known about the effect of self-association on the structural properties and conformational stability of partially folded protein molecules. G-actin is shown to form equilibrium unfolding intermediate in the vicinity of 1.5 M guanidinium chloride (GdmCl). Refolding from the GdmCl unfolded state is terminated at the stage of formation of the same intermediate state. An analogous form, known as inactivated actin, can be obtained by heat treatment, or at moderate urea concentration, or by the release of Ca(2+). In all cases actin forms specific associates comprising partially folded protein molecules. The structural properties and conformational stability of inactivated actin were studied over a wide range of protein concentrations, and it was established that the process of self-association is rather specific. We have also shown that inactivated actin, being denatured, is characterized by a relatively rigid microenvironment of aromatic residues and exhibits a considerable limitation in the internal mobility of tryptophans. This means that specific self-association can play an important structure-forming role for the partially folded protein molecules.     

Male and female brain evolution is subject to contrasting selection pressures in primates

The claim that differences in brain size across primate species has mainly been driven by the demands of sociality (the "social brain" hypothesis) is now widely accepted. Some of the evidence to support this comes from the fact that species that live in large social groups have larger brains, and in particular larger neocortices. Lindenfors and colleagues (BMC Biology 5:20) add significantly to our appreciation of this process by showing that there are striking differences between the two sexes in the social mechanisms and brain units involved. Female sociality (which is more affiliative) is related most closely to neocortex volume, but male sociality (which is more competitive and combative) is more closely related to subcortical units (notably those associated with emotional responses). Thus different brain units have responded to different selection pressures.     

Complete nucleotide sequences of bovine alpha S2- and beta-casein cDNAs: comparisons with related sequences in other species

The nucleotide sequences corresponding to bovine alpha S2- and beta- casein mRNAs have been determined by cDNA analysis. Both sequences appear to be complete at their 5' ends. The nucleotide sequence of alpha S2-casein, when compared with the corresponding cavine A sequence, helps to define the boundaries of a large amino acid repeat (approximately 80 residues) whereas comparisons with the nucleotide sequences of rat gamma- and mouse epsilon-casein mRNAs also reveal extensive sequence similarities. An alignment of these four sequences shows that the divergence of their translated regions has been characterized by the duplication and deletion of discrete segments of sequence that probably correspond to exons. A high degree of nucleotide substitution is also found when the four sequences are compared, except for well-conserved leader-peptide and phosphorylation-site sequences and, to a lesser extent, the 5'-untranslated regions. Similar comparison of the bovine and rat beta-caseins shows that their divergence has involved a high rate of nucleotide substitution but that no major insertions or deletions of sequence have occurred. The several splice sites that have veen defined in the rat beta-casein gene are likely to have been conserved in the bovine. The contrasting evolutionary histories of the alpha- and beta-casein coding sequences correlate with the distinctive functions of these proteins in the casein micelle system in milk.      

Rapid ex vivo expansion of highly enriched human invariant natural killer T cells via single antigenic stimulation for cell therapy to prevent graft-versus-host disease

Background aims

CD1d-restricted invariant natural killer (iNK) T cells are rare regulatory T cells that may contribute to the immune-regulation in allogeneic stem cell transplantation (ASCT). Here, we sought to develop an effective strategy to expand human iNK T cells for use in cell therapy to prevent graft-versus-host disease (GVHD) in ASCT.