Monoclonal antibodies against beta-galactoside-binding lectin of chick embryo recognizes conformational change of the antigen

Monoclonal antibodies against chick embryonic beta-galactoside-binding lectin were obtained. One of the monoclonal antibodies was ineffective in Western blotting and seemed to be unable to bind the SDS-denatured lectin. When the native lectin was dotted on a nitrocellulose filter and subjected to denaturation by treatment with SDS, urea or heat, binding of this antibody no longer occurred, though other monoclonal antibodies bound normally. This antibody seems to have been raised against an epitope which is destroyed upon denaturation.     

Positive anemotaxis by Varroa mites: responses to bee odour plumes and single clean‐air puffs

Abstract.The stimuli and mechanisms mediating host location and host choice by the bee mite, Varroa jacobsoni (Oudemans), are currently unknown. It is shown that Varroa can use single clean‐air puffs and bee‐odour plumes in a wind tunnel as directional cues. Varroa turned nearly straight upwind in response to single 0.1‐s puffs of clean air directed at 90° to the their anterior‐posterior axis. They turned significantly further to their left side (104°) than to their right (76°), but showed no difference in latency to initiation of the turns (means of 63.3 ms vs. 62.6 ms, respectively). They also followed bee‐odour plumes in a wind tunnel. When released in odour and control plumes mid‐way between the plume's origin and the downwind end of the tunnel, mites responding to bee‐odour walked upwind in, or along the edge of, the odour plume with 38% making contact with the odour delivery tube; mites in clean air did not walk upwind along the air stream, and none made contact with the air delivery tube. Walking speeds were not different between the bee‐odour and control groups (0.28 vs. 0.29 cm s^–1); there were also no differences in the turning rates (96.85 vs. 97.16 deg s^–1 and 388.08 vs. 379.18 deg cm^–1, respectively). Under all conditions, mites walked in a zigzag fashion.     

Imaging Ca2+ concentration changes at the secretory vesicle surface with a recombinant targeted cameleon.

Regulated exocytosis involves the Ca(2+)-triggered fusion of secretory vesicles with the plasma membrane, by activation of vesicle membrane Ca(2+)-binding proteins [1]. The Ca(2+)-binding sites of these proteins are likely to lie within 30 nm of the vesicle surface, a domain in which changes in Ca2+ concentration cannot be resolved by conventional fluorescence microscopy. A fluorescent indicator for Ca2+ called a yellow 'cameleon' (Ycam2) - comprising a fusion between a cyan-emitting mutant of the green fluorescent protein (GFP), calmodulin, the calmodulin-binding peptide M13 and an enhanced yellow-emitting GFP - which is targetable to specific intracellular locations, has been described [2]. Here, we generated a fusion between phogrin, a protein that is localised to secretory granule membranes [3], and Ycam2 (phogrin-Ycam2) to monitor changes in Ca2+ concentration ([Ca2+]) at the secretory vesicle surface ([Ca2+]gd) through alterations in fluorescence resonance energy transfer (FRET) between the linked cyan and yellow fluorescent proteins (CFP and YFP, respectively) in Ycam2. In both neuroendocrine PC12 and MIN6 pancreatic beta cells, apparent resting values of cytosolic [Ca2+] and [Ca2+](gd) were similar throughout the cell. In MIN6 cells following the activation of Ca2+ influx, the minority of vesicles that were within approximately 1 microm of the plasma membrane underwent increases in [Ca2+](gd) that were significantly greater than those experienced by deeper vesicles, and greater than the apparent cytosolic [Ca2+] change. The ability to image both global and compartmentalised [Ca2+] changes with recombinant targeted cameleons should extend the usefulness of these new Ca2+ probes.     

Are economic selection indices always superior to a desired gains index?

Conclusions The comparison of different selection indices is justified only if the indices are constrated to achieve the same profit function, even when each index is not optimized with respect to that profit function.When a profit function is known and is non-linear, the desired gains index may be more efficient than the economic index. The optimum desired gains index should be determined by iterative techniques over several generations to compare the genetic progress with the economic index, because gains by the economic index are not linear and the changes observed in the initial generations of selection are not the same rates in future generations, although those changes are linear in the case of the desired gains index.