Do woodpecker finches acquire tool-use by social learning?

Tool-use is widespread among animals, but except in primates the development of this behaviour is poorly known. Here, we report on the first experimental study to our knowledge of the mechanisms underlying the acquisition of tool-use in a bird species. The woodpecker finch Cactospiza pallida, endemic to the Galápagos Islands, is a famous textbook example of tool-use in animals. This species uses modified twigs or cactus spines to pry arthropods out of tree holes. Using nestlings and adult birds from the field, we tested experimentally whether woodpecker finches learn tool-use socially. We show that social learning is not essential for the development of tool-use: all juveniles developed tool-use regardless of whether or not they had a tool-using model. However, we found that not all adult woodpecker finches used tools in our experiments. These non-tool-using individuals also did not learn this task by observing tool-using conspecifics. Our results suggest that tool-use behaviour depends on a very specific learning disposition that involves trial-and-error learning during a sensitive phase early in ontogeny.     

1-Alkyl-3-amino-5-aryl-1H-[1,2,4]triazoles: novel synthesis via cyclization of N-acyl-S-methylisothioureas with alkylhydrazines and their potent corticotropin-releasing factor-1 (CRF(1)) receptor antagonist activities.

Cyclizations of alkylhydrazines with N-acyl-S-methylisothioureas, readily synthesized from acyl chlorides, sodium thioisocyanate, dialkylamines then methyl iodide in a one-pot reaction, gave 1-alkyl-3-dialkylamino-5-phenyltriazoles 7 as major products. The regioisomers were assigned through the use of NOE NMR experiments. While bearing a N-bis(cyclopropyl)methyl-N-propylamino group, this series of compounds shows very good binding affinity on the human CRF₁ receptor. Among them, 1-methyl-3-[N-bis(cyclopropyl)methyl-N-propylamino]-5-(2,4-dichlorophenyl)-1H-[1,2,4]triazole 7a had the best binding affinity for the CRF₁ receptor (K_i=9 nM).     

The light organ symbiont Vibrio fischeri possesses two distinct secreted ADP-ribosyltransferases.

We have previously described the purification, cloning, and initial characterization of a secreted ADP-ribosyltransferase, halovibrin (gene designation hvn), from the luminescent light organ symbiont Vibrio fischeri. This report describes a strategy for overexpression of halovibrin, the production and refinement of antihalo-vibrin antisera, and the molecular biological construction of a V. fischeri halovibrin null strain. Biochemical analysis of this mutant revealed that V. fischeri hvn null still possessed ADP-ribosyltransferase activity and that this activity is immunologically, genetically, and structurally distinct from the previously described enzyme. This unusual finding, of two ADP-ribosyltransferase enzymes produced by a microorganism, is complemented by the details of the purification to apparent homogeneity and in vitro regulation of this new protein, halovibrin-beta.     

Escherichia coli CAN lacks a tRNA-processing nuclease.

Escherichia coli strain CAN is unable to support the growth of bacteriophage T4 strains requiring the suppressor function of T4 tRNASer. Biochemical analysis of the mutant strain revealed that it is deficient in a RNase which acts on the artificial tRNA precursor tRNA-C-U.