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The role and use of olfactory cues by penguins is largely under‐investigated, with only a few studies suggesting that odours are involved in prey detection, orientation and for interspecific communication. This also applies to King Penguins Aptenodytes patagonicus where little is known about their chemoreception abilities and, subsequently, the role of odours in their behavioural ecology. Here, we investigated the chemical composition of volatile organic compounds (VOCs) from feathers of King Penguins in the Kerguelen Archipelago and their potential to carry information on identity and sex. We analysed VOCs using direct thermal desorption, a novel approach for extracting volatile compounds directly from solid matrices. We were only able to test at desorption temperatures of 70 and 100 °C to optimize conditions for VOC analysis. We found a profile of 26 VOCs present in most individuals, which varied significantly between individuals but not between sexes. Results suggested that VOCs could possibly be used by King Penguins to locate the colony and recognize individuals, if similar VOCs are also present at ambient conditions. Further studies and behavioural experiments are encouraged to explore olfactory‐based communication in this species. [ABSTRACT FROM AUTHOR]

Many Lepidoptera larvae use pieces of vegetation bound with silk to construct or disguise their cocoons. Here we report the first known case of a caterpillar building its cocoon entirely out of fragments of resin, broken away from sheets of dried resin on the trunk of a tree and held together with silk. The behaviour of the larva (possiblyNegritothripasp. in the Nolidae), from the Kinabatangan Wildlife Sanctuary in Sabah, Borneo, is described. The cocoon was constructed on the trunk ofVatica rassak(Dipterocarpaceae). Analysis of resin from the cocoon, using gas chromatography-mass spectrometry, revealed a complex mixture of 260 components, dominated by sesquiterpenes and triterpenes. Many of these compounds have defensive properties, protecting the tree from herbivores and fungi. The larva appears to have evolved an elaborate and possibly unique behaviour, allowing it to harness the defensive properties of the resin to protect its pupa from predators and/or entomopathogenic fungi. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) is a potent activator of large conductance, calcium-dependent potassium (BKCa) channels of vascular myocytes and carotid body glomus cells or when heterologously expressed. Using the human BKCa channel α1-subunit ( hSlo1; KCNMA1) stably and transiently expressed in human embryonic kidney 293 cells, the mechanism and structural basis of channel activation by CO was investigated in inside–out, excised membrane patches. Activation by CO was concentration dependent (EC50 ∼20 μM), rapid, reversible, and evoked a shift in the V0.5 of −20 mV. CO evoked no changes in either single channel conductance or in deactivation rate but augmented channel activation rate. Activation was independent of the redox state of the channel, or associated compounds/protein partners, and was partially dependent on [Ca2+]i in the physiological range (100–1,000 nM). Importantly, CO “super-stimulated” BKCa activity even in saturating [Ca2+]i. Single or double mutation of two histidine residues previously implicated in CO sensing did not suppress CO activation but replacing the S9–S10 module of the C-terminal of Slo1 with that of Slo3 completely prevented the action of CO. These findings show that a motif in the S9–S10 part of the C-terminal is essential for CO activation and suggest that this gas transmitter activates the BKCa channel by redox-independent changes in gating. [ABSTRACT FROM AUTHOR]

Using two-photon scanning laser microscopy, we investigated the effect of an Allium sativum (garlic) constituent, diallyl disulphide (DADS), on key physiological functions of the opportunistic pathogen Candida albicans. A short 30 min exposure to 0.5 m M DADS followed by removal induced 70% cell death (50% necrotic, 20% apoptotic) within 2 h, increasing to 75% after 4 h. The early intracellular events associated with DADS-induced cell death were monitored with two-photon fluorescence microscopy to track mitochondrial membrane potential (Δψm), reactive oxygen species (ROS) and NADH or reduced glutathione (GSH) under aerobic conditions. DADS treatment decreased intracellular GSH and elevated intracellular ROS levels. Additionally, DADS induced a marked decrease of Δψm and lowered respiration in cell suspensions and isolated mitochondria. In vitro kinetic experiments in cell-free extracts suggest that glutathione-S-transferase (GST) is one of the intracellular targets of DADS. Additional targets were also identified, including inhibition of a site or sites between complexes II-IV in the electron transport chain, as well as the mitochondrial ATP-synthase. The results indicate that DADS is an effective antifungal agent able to trigger cell death in Candida, most probably by eliciting oxidative stress as a consequence of thiol depletion and impaired mitochondrial function. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Nereis succinea and Platynereis dumerilii (Annelida, Polychaeta) are broadcast spawners and reproduce semelparously. The final events in reproduction, swarming and spawning are co-ordinated by sex pheromones. A water-soluble fraction of crude oil, the volatile fraction (C9--C16) of EKO FISK crude oil was found to induce release of gametes in male nereids at levels <0.3 ppm. Using vacuum distillation, column chromatography, preparative GC and GC-MS analysis we showed that C5-alkylated benzenes were most potent in inducing sperm release, of those n-butyl-4-methylbenzene and 1,4-diethyl-2-methylbenzene were found to induce release of gametes at concentrations ≥4 nM. This threshold is lower than those reported for natural pheromones (nereithione: 60 nM, uric acid: 600 nM) but higher than background levels of aromatic compounds of 0.05 nM and below. Other oil fractions showed additional effects, blocking pheromone reception or narcotising and intoxicating animals. Part of these effects could be assigned to naphthalenes at levels down to approx. 320 nM. In the original mixtures, their action was modified or compensated by the presence of gamete release inducing alkylated benzenes. Other highly paralysing substances remained elusive. [ABSTRACT FROM AUTHOR]

Examines the cell death mechanism in the human opportunistic pathogen Candida albicans. Difficulty during the chemotherapy of Candida albicans; Detection of programmed cell death induced by oxidative stress; Characteristics of apoptotic cell death.