The biogeochemistry of insectivorous cave guano: a case study from insular Southeast Asia

Cave guano derived from insectivorous bats and birds contain unique geochemical and mineralogical signatures. We investigated the mineralogy, pH, C, N and metal abundance patterns of cave guano spatially and temporally (with depth) along a W–E transect in Malaysia and Palawan from five remote cave sites, each housing large populations of bats and Aerodramus spp.(cave swiftlets). Guano deposits were rich in phosphate and/or sulphate minerals (e.g., gypsum, bassanite) with leucophosphite, spheniscidite, and variscite present in most profiles. Metal abundances measured from modern and ancient bat guano revealed high concentrations of transition metals relative to the local environment. Highly enriched metals, however, were associated with phosphate rather than sulphate minerals. Copper and Zn were enriched in all profiles, whereas other metals were associated with specific caves consistent with known local mineral resources. For example, Sn, Pb, and Rb were particularly enriched in Batu Cave, located in the Peninsular Malaysian granitic tin belt, whereas Ni and Cr were high in regions associated with ultramafic ophiolites and Ni-laterites found on Palawan

Field metabolic rates of teleost fishes are recorded in otolith carbonate

Field metabolic rate (FMR) is key to understanding individual and population-level responses to environmental changes, but is challenging to measure in field conditions, particularly in aquatic environments. Here we show that FMR can be estimated directly from the isotopic composition of carbon in fish otoliths (δ13Coto). We describe the relationship between δ13Coto values and oxygen consumption rate, and report results from laboratory experiments relating individual-level measurements of oxygen consumption rates to δ13Coto values in Atlantic cod (Gadus morhua). We apply our new δ13Coto metabolic proxy to existing δ13Coto data from wild cod and four deepwater fish species to test the validity of inferred FMR estimates. The δ13Coto metabolic proxy offers a new approach to study physiological ecology in free-ranging wild fishes. Otolith-based proxies for FMR are particularly promising as they allow retrospective assessment of time-integrated, individual-level FMR throughout an individual fish’s life history

Data from: Field metabolic rates of teleost fishes are recorded in otolith carbonate

Field metabolic rate (FMR) is key to understanding individual and population-level responses to environmental changes, but is challenging to measure in field conditions, particularly in aquatic environments. Here we show that FMR can be estimated directly from the isotopic composition of carbon in fish otoliths (δ13Coto). We describe the relationship between δ13Coto values and oxygen consumption rate, and report results from laboratory experiments relating individual-level measurements of oxygen consumption rates to δ13Coto values in Atlantic cod (Gadus morhua). We apply our new δ13Coto metabolic proxy to existing δ13Coto data from wild cod and four deepwater fish species to test the validity of inferred FMR estimates. The δ13Coto metabolic proxy offers a new approach to study physiological ecology in free-ranging wild fishes. Otolith-based proxies for FMR are particularly promising as they allow retrospective assessment of time-integrated, individual-level FMR throughout an individual fish’s life history

IL-4: an important cytokine in determining the fate of T cells

The pleiotropic effect of cytokines has been well documented, but the effects triggered by unique cytokines in different T cell types are still under investigation. The most relevant findings on the influence of interleukin-4 (IL-4) on T cell activation, differentiation, proliferation, and survival of different T cell types are discussed in this review. The main aim of our study was to correlate the observed effect with the corresponding molecular mechanism induced on IL-4/IL-4R interaction, in an effort to understand how the same extracellular stimuli can trigger a wide spectrum of signaling pathways leading to different responses in each T cell type