Control of common bunt of wheat under field conditions with the biofumigant fungus <Emphasis Type="Italic">Muscodor albus</Emphasis>

Field experiments were conducted to evaluate the biological control potential of the fungus Muscodor albus, when applied as a seed treatment or an in furrow soil treatment, for control of common bunt (CB) of wheat caused by Tilletia caries. For seed treatments, dry rye grain culture of M. albus was ground into powder and applied, at a rate of 125 mg/g seed, to wheat seed infested with T. caries teliospores. The culture was also cracked into particles and applied in furrow at the rate of 4 g/m of row, along with teliospore infested seed during planting. Treatments were evaluated during two growing seasons and two planting dates beginning in early spring when soil temperatures were optimal for disease development (5–10°C), and then approximately 3 weeks later. In the first year, treatments in the first seeding date reduced CB from 44% diseased spikes in untreated controls to 12% and 9% in seed and in furrow treatments respectively, and from 6% in controls to 0% in both treatments in the second seeding date. In the second year, CB was reduced from 8% in controls to 0.5% and 0.25% for seed and in furrow treatments respectively in the first seeding date, and from 0.75% in controls to 0% in both the treatments in the second seeding date. M. albus may have potential for CB control in organic wheat production where options for managing the disease are very limited.     

Synthesis,Structural and Pharmacological Characterizations of CIC,a Novel α-Conotoxin with an Extended N-Terminal Tail

Cone snails are venomous marine predators that rely on fast-acting venom to subdue their prey and defend against aggressors. The conotoxins produced in the venom gland are small disulfide-rich peptides with high affinity and selectivity for their pharmacological targets. A dominant group comprises α-conotoxins, targeting nicotinic acetylcholine receptors. Here, we report on the synthesis, structure determination and biological activity of a novel α-conotoxin, CIC, found in the predatory venom of the piscivorous species Conus catus and its truncated mutant Δ-CIC. CIC is a 4/7 α-conotoxin with an unusual extended N-terminal tail. High-resolution NMR spectroscopy shows a major influence of the N-terminal tail on the apparent rigidity of the three-dimensional structure of CIC compared to the more flexible Δ-CIC. Surprisingly, this effect on the structure does not alter the biological activity, since both peptides selectively inhibit α3β2 and α6/α3β2β3 nAChRs with almost identical sub- to low micromolar inhibition constants. Our results suggest that the N-terminal part of α-conotoxins can accommodate chemical modifications without affecting their pharmacology.     

Evidence of genotype–diet interactions in the response of rainbow trout (Oncorhynchus mykiss) clones to a diet with or without fishmeal at early growth

This study examined the genetic variability and genotype × diet interactions during early growth (initial mean body weight 1.2 g) among seven heterozygous clones of rainbow trout, Oncorhynchus mykiss. The clones were hand-fed a diet containing either fishmeal or plant proteins during a 49-day trial divided into two periods (P1, 26 days, and P2, 23 days). Weight, variation of weight within clone, feed intake, feed efficiency and mortality were calculated for both periods.There was a highly significant effect of diet and of clone for all traits at both periods, except for feed efficiency and mortality at P1. Highly significant interactions between diet and clone were also recorded for all these traits, except for mortality at P1. The occurrence of genotype × diet interactions when feeding juvenile rainbow trout with an all plant-protein diet indicates that a highly performing genotype on a fishmeal diet may perform poorly when fed a plant-protein diet. Interactions were found for the two major determinants of growth, i.e. feed intake and feed efficiency, showing that the dietary response differs according to the genotype. Monitoring of the within-clone variability of weight showed that a plant-based diet is likely to enhance the overall phenotypic variance in a population, whatever its initial genetic variability.     

Growth and reproduction of threatened native crucian carp Carassius carassius in small ponds of Epping Forest,south‐east England

• 1. The crucian carp Carassius carassius is a species of cyprinid fish native to south‐east England, but few studies exist on its growth and reproduction in England, and the species is threatened by introductions of its Asiatic congener, goldfish Carassius auratus. To increase knowledge of the crucian carp as a means of aiding its conservation, the present study assesses the growth (back‐calculated length at age, body condition) and reproduction (fecundity, egg size, length and age at maturity) of crucian carp in small ponds of Epping Forest (north‐east London, England).
• 2. Evaluation of growth and reproduction data with published data for populations from northern Europe (i.e. latitude ?50°) suggest that growth is very variable, even within the same area, and that data on reproductive indices, in particular length and age at maturity, are scarce. In England, the length at age trajectory of crucian carp living in sympatry with feral goldfish Carassius auratus did not differ significantly from allopatric crucian carp populations, but crucian carp body condition and relative fecundity (eggs per body weight) were highest, and mean age and standard length at maturity were lowest in sympatry with goldfish.
• 3. These data suggest that somatic growth and reproductive output may be maximized in crucian carp when confronted by coexistence with feral goldfish. However, the potential impact of goldfish introductions on crucian carp growth and reproduction requires further study, involving a much larger number of crucian carp populations, both in allopatry and sympatry with feral goldfish populations.

© Crown copyright 2009. Reproduced with the permission of Her Majesty's stationery Office. Published by John Wiley & Sons, Ltd.     

A potent and broad neutralizing antibody recognizes and penetrates the HIV glycan shield

The HIV envelope (Env) protein gp120 is protected from antibody recognition by a dense glycan shield. However, several of the recently identified PGT broadly neutralizing antibodies appear to interact directly with the HIV glycan coat. Crystal structures of antigen-binding fragments (Fabs) PGT 127 and 128 with Man(9) at 1.65 and 1.29 angstrom resolution, respectively, and glycan binding data delineate a specific high mannose-binding site. Fab PGT 128 complexed with a fully glycosylated gp120 outer domain at 3.25 angstroms reveals that the antibody penetrates the glycan shield and recognizes two conserved glycans as well as a short β-strand segment of the gp120 V3 loop, accounting for its high binding affinity and broad specificity. Furthermore, our data suggest that the high neutralization potency of PGT 127 and 128 immunoglobulin Gs may be mediated by cross-linking Env trimers on the viral surface.     

Spin crossover in ferropericlase at high pressure: a seismologically transparent transition?

Seismic discontinuities in Earth typically arise from structural, chemical, or temperature variations with increasing depth. The pressure-induced iron spin state transition in the lower mantle may influence seismic wave velocities by changing the elasticity of iron-bearing minerals, but no seismological evidence of an anomaly exists. Inelastic x-ray scattering measurements on (Mg(0.83)Fe(0.17))O-ferropericlase at pressures across the spin transition show effects limited to the only shear moduli of the elastic tensor. This explains the absence of deviation in the aggregate seismic velocities and, thus, the lack of a one-dimensional seismic signature of the spin crossover. The spin state transition does, however, influence shear anisotropy of ferropericlase and should contribute to the seismic shear wave anisotropy of the lower mantle.     

Retinoic acid controls the bilateral symmetry of somite formation in the mouse embryo

A striking characteristic of vertebrate embryos is their bilaterally symmetric body plan, which is particularly obvious at the level of the somites and their derivatives such as the vertebral column. Segmentation of the presomitic mesoderm must therefore be tightly coordinated along the left and right embryonic sides. We show that mutant mice defective for retinoic acid synthesis exhibit delayed somite formation on the right side. Asymmetric somite formation correlates with a left-right desynchronization of the segmentation clock oscillations. These data implicate retinoic acid as an endogenous signal that maintains the bilateral synchrony of mesoderm segmentation, and therefore controls bilateral symmetry, in vertebrate embryos.