Morphology,metabolism and behaviour: responses of three fishes with different lifestyles to acute hypoxia

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Threat-sensitive anti-intraguild predation behaviour: maternal strategies to reduce offspring predation risk in mites

Predation is a major selective force for the evolution of behavioural characteristics of prey. Predation among consumers competing for food is termed intraguild predation (IGP). From the perspective of individual prey, IGP differs from classical predation in the likelihood of occurrence because IG prey is usually more rarely encountered and less profitable because it is more difficult to handle than classical prey. It is not known whether IGP is a sufficiently strong force to evolve interspecific threat sensitivity in antipredation behaviours, as is known from classical predation, and if so whether such behaviours are innate or learned. We examined interspecific threat sensitivity in antipredation in a guild of predatory mite species differing in adaptation to the shared spider mite prey (i.e. Phytoseiulus persimilis, Neoseiulus californicus and Amblyseius andersoni). We first ranked the players in this guild according to the IGP risk posed to each other: A. andersoni was the strongest IG predator; P. persimilis was the weakest. Then, we assessed the influence of relative IGP risk and experience on maternal strategies to reduce offspring IGP risk: A. andersoni was insensitive to IGP risk. Threat sensitivity in oviposition site selection was induced by experience in P. persimilis but occurred independently of experience in N. californicus. Irrespective of experience, P. persimilis laid fewer eggs in choice situations with the high- rather than low-risk IG predator. Our study suggests that, similar to classical predation, IGP may select for sophisticated innate and learned interspecific threat-sensitive antipredation responses. We argue that such responses may promote the coexistence of IG predators and prey.     

Octahedral Co(III) complexes of 2-(phenylimino)pyrrolyl ligands: Synthesis and structural characterisation

The reactions of CoCl₂ with three equivalents of 2-(phenylimino)pyrrolyl sodium salts, performed under a nitrogen atmosphere, lead to the formation of the Co(III) complexes [Co(κ²N,N′-NC₄H₃C(H)N-C₆H₅)₃] (2a), [Co(κ²N,N′-NC₄H₃C(CH₃)N-C₆H₅)₃] (2b) and [Co(κ²N,N′-NC₁₆H₉C(H)N-C₆H₅)₃] (2c), accommodating three chelating iminopyrrolyl ligands. Complexes 2a-c were obtained in moderate yields, and their characterisation by ¹H, ¹³C NMR and X-ray diffraction show they are diamagnetic and have an octahedral geometry about the cobalt centre, respectively. Uncharacterised products were obtained in the same reaction involving ligand precursors such as 2-(2,6-dimethylphenylimino)pyrrolyl sodium salts, which is attributed to a greater steric hindrance in the coordination of three of these bulkier ligands. The redox behaviour of complexes 2a-c shows an irreversible reduction wave with a peak potential in the range −3.2 to −3.7 V. Upon reduction, the complexes decompose giving rise, in the case of 2a, to a redox pattern compatible with the formation of [Co(κ²N,N′-NC₄H₃C(H)N-C₆H₅)₂].     

Bacillus subtilis pgsE (Formerly ywtC) stimulates poly‐γ‐glutamate production in the presence of zinc

Poly‐γ‐glutamate (PGA) is a versatile nylon‐like material, and enhanced production of PGA is required for various bio‐industrial applications. In this study, we first examined the effects of available sugars on the production of Bacillus subtilis PGA, and demonstrated the good applicability of pentoses (e.g., D ‐xylose). Then, we characterized the pgsE gene of B. subtilis, which encodes a 6.5‐kDa protein of 55 amino acids (PgsE), as a genetic tool for increasing the yield of PGA without changing its structural features (e.g., polymer stereochemistry and molecular size distribution). In the presence of Zn²⁺, the induction of PgsE tripled the PGA productivity of B. subtilis subsp. chungkookjang. This finding will contribute to the establishment of an improved PGA‐production system. Biotechnol. Bioeng. 2011; 108:226–230. © 2010 Wiley Periodicals, Inc.     

Pressure effects on lipid membrane structure and dynamics

The effect of hydrostatic pressure on lipid structure and dynamics is highly important as a tool in biophysics and bio-technology, and in the biology of deep sea organisms. Despite its importance, high hydrostatic pressure remains significantly less utilised than other thermodynamic variables such as temperature and chemical composition. Here, we give an overview of some of the theoretical aspects which determine lipid behaviour under pressure and the techniques and technology available to study these effects. We also summarise several recent experiments which highlight the information available from these approaches.