Capsule: The structure of Great Tit Parus major songs is shaped by the acoustic properties of the habitat within the breeding territory of individuals.
Aim: To test whether the structure of the habitat influences song structure within a population of Great Tits P. major.
Methods: We recorded Great Tit songs from 42 territories on two different days and measured the habitat structure in each territory. We also trapped the males and estimated the breeding density around each territory, so were able to control the analysis by date, breeding density and male characteristics.
Results: Song pause length was positively affected by the ground cover, while the song rate and the minimum frequency were negatively affected by the shrub cover. Male size negatively affected the peak frequency of the songs, whereas the age of the males affected the frequency range; older males sang with a broader bandwidth.
Conclusion: This study suggests that Great Tits are capable of adjusting their vocalizations in each territory, presumably to enhance transmission owing to vocal plasticity. 相似文献
Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well‐known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near‐future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, ‘Analysing vocal sequences in animals’. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial‐style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality. 相似文献
The sensory drive hypothesis proposes that environmental factors affect both signalling dynamics and the evolution of signals and receivers. Sound detection and equilibrium in marine fishes are senses dependent on the sagittae otoliths, whose morphological variability appears intrinsically linked to the environment. The aim of this study was to understand if and which environmental factors could be conditioning the evolution of this sensory structure, therefore lending support to the sensory drive hypothesis. Thus, we analysed the otolith shape of 42 rockfish species (Sebastes spp.) to test the potential associations with the phylogeny, biological (age), ecological (feeding habit and depth distribution) and biogeographical factors. The results showed strong differences in the otolith shapes of some species, noticeably influenced by ecological and biogeographical factors. Moreover, otolith shape was clearly conditioned by phylogeny, but with a strong environmental effect, cautioning about the use of this structure for the systematics of rockfishes or other marine fishes. However, our most relevant finding is that the data supported the sensory drive hypothesis as a force promoting the radiation of the genus Sebastes. This hypothesis holds that adaptive divergence in communication has significant influence relative to other life history traits. It has already been established in Sebastes for visual characters and organs; our results showed that it applies to otolith transformations as well (despite the clear influence of feeding and depth), expanding the scope of the hypothesis to other sensory structures. 相似文献
Nonstructural protein 1 (NS1) plays a crucial function in the replication, spread, and pathogenesis of influenza virus by inhibiting the host innate immune response. Here we report the discovery and optimization of novel pyrazolopyridine NS1 antagonists that can potently inhibit influenza A/PR/8/34 replication in MDCK cells, rescue MDCK cells from cytopathic effects of seasonal influenza A strains, reverse NS1-dependent inhibition of IFN-β gene expression, and suppress the slow growth phenotype in NS1-expressing yeast. These pyrazolopyridines will enable researchers to investigate NS1 function during infection and how antagonists can be utilized in the next generation of treatments for influenza infection. 相似文献
Peroxiredoxins are thiol‐dependent peroxidases that function in peroxide detoxification and H2O2 induced signaling. Among the six isoforms expressed in humans, PRDX1 and PRDX2 share 97% sequence similarity, 77% sequence identity including the active site, subcellular localization (cytosolic) but they hold different biological functions albeit associated with their peroxidase activity. Using recombinant human PRDX1 and PRDX2, the kinetics of oxidation and hyperoxidation with H2O2 and peroxynitrite were followed by intrinsic fluorescence. At pH 7.4, the peroxidatic cysteine of both isoforms reacts nearly tenfold faster with H2O2 than with peroxynitrite, and both reactions are orders of magnitude faster than with most protein thiols. For both isoforms, the sulfenic acids formed are in turn oxidized by H2O2 with rate constants of ca 2 × 103 M?1 s?1 and by peroxynitrous acid significantly faster. As previously observed, a crucial difference between PRDX1 and PRDX2 is on the resolution step of the catalytic cycle, the rate of disulfide formation (11 s?1 for PRDX1, 0.2 s?1 for PRDX2, independent of the oxidant) which correlates with their different sensitivity to hyperoxidation. This kinetic pause opens different pathways on redox signaling for these isoforms. The longer lifetime of PRDX2 sulfenic acid allows it to react with other protein thiols to translate the signal via an intermediate mixed disulfide (involving its peroxidatic cysteine), whereas PRDX1 continues the cycle forming disulfide involving its resolving cysteine to function as a redox relay. In addition, the presence of C83 on PRDX1 imparts a difference on peroxidase activity upon peroxynitrite exposure that needs further study. 相似文献
Toxoplasma gondii causes retinitis and encephalitis. Avoiding targeting by autophagosomes is key for its survival because T. gondii cannot withstand lysosomal degradation. During invasion of host cells, T. gondii triggers epidermal growth factor receptor (EGFR) signalling enabling the parasite to avoid initial autophagic targeting. However, autophagy is a constitutive process indicating that the parasite may also use a strategy operative beyond invasion to maintain blockade of autophagic targeting. Finding that such a strategy exists would be important because it could lead to inhibition of host cell signalling as a novel approach to kill the parasite in previously infected cells and treat toxoplasmosis. We report that T. gondii induced prolonged EGFR autophosphorylation. This effect was mediated by PKCα/PKCβ ? Src because T. gondii caused prolonged activation of these molecules and their knockdown or incubation with inhibitors of PKCα/PKCβ or Src after host cell invasion impaired sustained EGFR autophosphorylation. Addition of EGFR tyrosine kinase inhibitor (TKI) to previously infected cells led to parasite entrapment by LC3 and LAMP‐1 and pathogen killing dependent on the autophagy proteins ULK1 and Beclin 1 as well as lysosomal enzymes. Administration of gefitinib (EGFR TKI) to mice with ocular and cerebral toxoplasmosis resulted in disease control that was dependent on Beclin 1. Thus, T. gondii promotes its survival through sustained EGFR signalling driven by PKCα/β ? Src, and inhibition of EGFR controls pre‐established toxoplasmosis. 相似文献
Experiments were performed: (i) to investigate potential age- and gender-dependent differences in mutagenic responses in T cells following exposures of B6C3F1 mice and F344 rats by inhalation for 2 weeks to 0 or 1250 ppm butadiene (BD), and (ii) to determine if exposures for 2 weeks to 62.5 ppm BD produce a mutagenic effect in female rats. To evaluate the effect of age on mutagenic response, mutant manifestation curves for splenic T cells of female mice exposed at 8-9 weeks of age were defined by measuring Hprt mutant frequencies (MFs) at multiple time points after BD exposure using a T cell cloning assay and comparing the resulting mutagenic potency estimate (calculated as the difference of areas under the mutant manifestation curves of treated versus control animals) to that reported for female mice exposed to BD in the same fashion beginning at 4-5 weeks of age. The shapes of the mutant T cell manifestation curves for spleens were different [e.g., the maximum BD-induced MFs in older mice (8.0+/-1.0 [S.D.]x10(-6)) and younger mice (17.8+/-6.1 x 10(-6)) were observed at 8 and 5 weeks post-exposure, respectively], but the mutagenic burden was the same for both age groups. To assess the effect of gender on mutagenic response, female and male rodents were exposed to BD at 4-5 weeks of age and Hprt MFs were measured when maximum MFs are expected to occur post-exposure. The resulting data demonstrated that the pattern for mutagenic susceptibility from high-level BD exposure is female mice>male mice>female rats>male rats. Exposures of female rats to 62.5 ppm BD caused a minor but significant mutagenic response compared with controls (n=16/group; P=0.03). These results help explain part of the differing outcomes/interpretations of data in earlier Hprt mutation studies in BD-exposed rodents. 相似文献
Herbaspirillum seropedicae is an endophytic diazotroph associated with economically important crops such as rice, sugarcane, and wheat. Here, we present a 2-D reference map for H. seropedicae. Using MALDI-TOF-MS we identified 205 spots representing 173 different proteins with a calculated average of 1.18 proteins/gene. Seventeen hypothetical or conserved hypothetical ORFs were shown to code for true gene products. These data will support the genome annotation process and provide a basis on which to undertake comparative proteomic studies. 相似文献
The names Quercus ballota and Q. rotundifolia (Fagaceae), referring to taxa sometimes considered conspecific with the widely distributed Q. ilex, are discussed and typified. A specimen preserved at MPU is designated as the lectotype of Desfontaines's name Q. ballota. Lamarck's name Q. rotundifolia is neotypified using a specimen preserved at VAL, with several duplicates in other European herbaria. 相似文献
Honey is a natural product made by honey bees from the nectar of flowers or secretions produced by other living plant parts. The metal content of the honeys is related to the levels of metals in the environment. Due to the importance of honey in the human diet and the increase of environmental pollution, it is necessary to determine the content of metals in honey to evaluate the toxicological risk derived from its consumption. The objective of this study was to determine the content of 20 metals (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, V, and Zn) in different samples of artisanal honey from the Canary Islands (Spain) in order to evaluate the dietary intake derived from the consumption of these honeys. A total of 161 samples of different types of Canary honey were analyzed by ICP-OES (inductively coupled plasma–optical emission spectrometry). K (825 mg/kg) was the macroelement found in highest concentration, while B (4.25 mg/kg) was the trace element with the highest mean concentration. Al (3.33 mg/kg) was the most abundant toxic metal, followed by Pb (0.040 mg/kg) and Cd (0.002 mg/kg). A mean consumption of 25 g/day of honey mainly contributes to the recommended daily intake of Cu (1.34% adults) and K (0.67% adults). As regards the toxic metals, the contribution percentage to the TDI (tolerable daily intake) of Pb at 2.92% for adults is noteworthy. However, the consumption of honey does not imply a high intake of metals and, therefore, does pose a risk to the health of adult men and women.