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Sample records for ciliary genes predated

  1. Convergent evolution of RFX transcription factors and ciliary genes predated the origin of metazoans

    Directory of Open Access Journals (Sweden)

    Chen Nansheng

    2010-05-01

    Full Text Available Abstract Background Intraflagellar transport (IFT genes, which are critical for the development and function of cilia and flagella in metazoans, are tightly regulated by the Regulatory Factor X (RFX transcription factors (TFs. However, how and when their evolutionary relationship was established remains unknown. Results We have identified evidence suggesting that RFX TFs and IFT genes evolved independently and their evolution converged before the first appearance of metazoans. Both ciliary genes and RFX TFs exist in all metazoans as well as some unicellular eukaryotes. However, while RFX TFs and IFT genes are found simultaneously in all sequenced metazoan genomes, RFX TFs do not co-exist with IFT genes in most pre-metazoans and thus do not regulate them in these organisms. For example, neither the budding yeast nor the fission yeast possesses cilia although both have well-defined RFX TFs. Conversely, most unicellular eukaryotes, including the green alga Chlamydomonas reinhardtii, have typical cilia and well conserved IFT genes but lack RFX TFs. Outside of metazoans, RFX TFs and IFT genes co-exist only in choanoflagellates including M. brevicollis, and only one fungus Allomyces macrogynus of the 51 sequenced fungus genomes. M. brevicollis has two putative RFX genes and a full complement of ciliary genes. Conclusions The evolution of RFX TFs and IFT genes were independent in pre-metazoans. We propose that their convergence in evolution, or the acquired transcriptional regulation of IFT genes by RFX TFs, played a pivotal role in the establishment of metazoan.

  2. Identification of Ciliary and Ciliopathy Genes in Caenorhabditis Elegans through Comparative Genomics

    OpenAIRE

    Chen, Nansheng; Mah, Allan; Oliver E Blacque; Chu, Jeffrey; Phgora, Kiran; Bakhoum, Mathieu W.; Newbury, C. Rebecca Hunt; Khattra, Jaswinder; Chan, Susanna; Efimenko, Evgheni; Johnsen, Robert; Phirke, Prasad; Swoboda, Peter; Marra, Marco; Moerman, Donald

    2006-01-01

    Background The recent availability of genome sequences of multiple related Caenorhabditis species has made it possible to identify, using comparative genomics, similarly transcribed genes in Caenorhabditis elegans and its sister species. Taking this approach, we have identified numerous novel ciliary genes in C. elegans, some of which may be orthologs of unidentified human ciliopathy genes. Results By screening for genes possessing canonical X-box sequences in promoters of three Caenorhabditi...

  3. Localization of the gene for the ciliary neutrotrophic factor receptor (CNTFR) to human chromosome 9

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    Donaldson, D.H.; Jones, C.; Patterson, D. (Eleanor Roosevelt Institute, Denver, CO (United States) Univ. of Colorado Health Science Center, Denver, CO (United States)); Britt, D.E.; Jackson, C.L. (Brown Univ., Providence, RI (United States))

    1993-09-01

    Ciliary neurotrophic factor (CNTF) has recently been found to be important for the survival of motor neurons and has shown activity in animal models of amyotrophic lateral sclerosis (ALS). CNTF therefore holds promise as a treatment for ALS, and it and its receptor (CNTFR) are candidates for a gene involved in familial ALS. The CNTFR gene was mapped to chromosome 9 by PCR on a panel of human/CHO somatic cell hybrids and localized to 9p13 by PCR on a panel of radiation hybrids. 18 ref., 1 fig., 2 tabs.

  4. DNAH6 and Its Interactions with PCD Genes in Heterotaxy and Primary Ciliary Dyskinesia.

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    Li, You; Yagi, Hisato; Onuoha, Ezenwa Obi; Damerla, Rama Rao; Francis, Richard; Furutani, Yoshiyuki; Tariq, Muhammad; King, Stephen M; Hendricks, Gregory; Cui, Cheng; Saydmohammed, Manush; Lee, Dong Min; Zahid, Maliha; Sami, Iman; Leatherbury, Linda; Pazour, Gregory J; Ware, Stephanie M; Nakanishi, Toshio; Goldmuntz, Elizabeth; Tsang, Michael; Lo, Cecilia W

    2016-02-01

    Heterotaxy, a birth defect involving left-right patterning defects, and primary ciliary dyskinesia (PCD), a sinopulmonary disease with dyskinetic/immotile cilia in the airway are seemingly disparate diseases. However, they have an overlapping genetic etiology involving mutations in cilia genes, a reflection of the common requirement for motile cilia in left-right patterning and airway clearance. While PCD is a monogenic recessive disorder, heterotaxy has a more complex, largely non-monogenic etiology. In this study, we show mutations in the novel dynein gene DNAH6 can cause heterotaxy and ciliary dysfunction similar to PCD. We provide the first evidence that trans-heterozygous interactions between DNAH6 and other PCD genes potentially can cause heterotaxy. DNAH6 was initially identified as a candidate heterotaxy/PCD gene by filtering exome-sequencing data from 25 heterotaxy patients stratified by whether they have airway motile cilia defects. dnah6 morpholino knockdown in zebrafish disrupted motile cilia in Kupffer's vesicle required for left-right patterning and caused heterotaxy with abnormal cardiac/gut looping. Similarly DNAH6 shRNA knockdown disrupted motile cilia in human and mouse respiratory epithelia. Notably a heterotaxy patient harboring heterozygous DNAH6 mutation was identified to also carry a rare heterozygous PCD-causing DNAI1 mutation, suggesting a DNAH6/DNAI1 trans-heterozygous interaction. Furthermore, sequencing of 149 additional heterotaxy patients showed 5 of 6 patients with heterozygous DNAH6 mutations also had heterozygous mutations in DNAH5 or other PCD genes. We functionally assayed for DNAH6/DNAH5 and DNAH6/DNAI1 trans-heterozygous interactions using subthreshold double-morpholino knockdown in zebrafish and showed this caused heterotaxy. Similarly, subthreshold siRNA knockdown of Dnah6 in heterozygous Dnah5 or Dnai1 mutant mouse respiratory epithelia disrupted motile cilia function. Together, these findings support an oligogenic disease

  5. Gene expression and functional annotation of the human ciliary body epithelia.

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    Sarah F Janssen

    Full Text Available PURPOSE: The ciliary body (CB of the human eye consists of the non-pigmented (NPE and pigmented (PE neuro-epithelia. We investigated the gene expression of NPE and PE, to shed light on the molecular mechanisms underlying the most important functions of the CB. We also developed molecular signatures for the NPE and PE and studied possible new clues for glaucoma. METHODS: We isolated NPE and PE cells from seven healthy human donor eyes using laser dissection microscopy. Next, we performed RNA isolation, amplification, labeling and hybridization against 44×k Agilent microarrays. For microarray conformations, we used a literature study, RT-PCRs, and immunohistochemical stainings. We analyzed the gene expression data with R and with the knowledge database Ingenuity. RESULTS: The gene expression profiles and functional annotations of the NPE and PE were highly similar. We found that the most important functionalities of the NPE and PE were related to developmental processes, neural nature of the tissue, endocrine and metabolic signaling, and immunological functions. In total 1576 genes differed statistically significantly between NPE and PE. From these genes, at least 3 were cell-specific for the NPE and 143 for the PE. Finally, we observed high expression in the (NPE of 35 genes previously implicated in molecular mechanisms related to glaucoma. CONCLUSION: Our gene expression analysis suggested that the NPE and PE of the CB were quite similar. Nonetheless, cell-type specific differences were found. The molecular machineries of the human NPE and PE are involved in a range of neuro-endocrinological, developmental and immunological functions, and perhaps glaucoma.

  6. Rat ciliary neurothrophic factor (CNTF): gene structure and regulation of mRNA levels in glial cell cultures.

    OpenAIRE

    Carroll, Patrick; Sendtner, Michael; Meyer, Michael; Thoenen, Hans

    2009-01-01

    The structure of the rat ciliary neurotrophic factor (CNTF) gene and the regulation ofCNTF mRNA levels in cultured glial cells were investigated. The rat mRNA is encoded by a simple two-exon transcription unit. Sequence analysis of the region upstream of the transcription start-site did not reveal a typical TATA-box consensus sequence. Low levels of CNTF mRNA were detected in cultured Schwann cells, and CNTF mRNA was not increased by a variety of treatments. Three-week-old astrocyteenriched c...

  7. Ciliary neurotrophic factor coordinately activates transcription of neuropeptide genes in a neuroblastoma cell line.

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    Symes, A.J.; Rao, M S; Lewis, S. E.; Landis, S C; Hyman, S E; Fink, J S

    1993-01-01

    Differentiation factors have been identified that influence the phenotype of sympathetic neurons by altering expression of classical neurotransmitters and neuropeptides. Investigation of the molecular mechanisms through which such factors act would be facilitated by the availability of a neuronal cell line that responds to these factors in a fashion similar to sympathetic neurons. We have identified a human neuroblastoma cell line, NBFL, that responds to the differentiation factor ciliary neu...

  8. Sox10 regulates ciliary neurotrophic factor gene expression in Schwann cells

    OpenAIRE

    Ito, Yasuhiro; Wiese, Stefan; Funk, Natalja; Chittka, Alexandra; Rossoll, Wilfried; Bömmel, Heike; Watabe, Kazuhiko; Wegner, Michael; Sendtner, Michael

    2006-01-01

    Ciliary neurotrophic factor (Cntf) plays an essential role in postnatal maintenance of spinal motoneurons. Whereas the expression of this neurotrophic factor is low during embryonic development, it is highly up-regulated after birth in myelinating Schwann cells of rodents. To characterize the underlying transcriptional mechanisms, we have analyzed and compared the effects of various glial transcription factors. In contrast to Pit-1, Oct-1, Unc-86 homology region (POU) domain class 3, transcri...

  9. A case report of primary ciliary dyskinesia, laterality defects and developmental delay caused by the co-existence of a single gene and chromosome disorder.

    LENUS (Irish Health Repository)

    Casey, Jillian P

    2015-01-01

    Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disorder characterised by abnormal ciliary motion and impaired mucociliary clearance, leading to recurrent respiratory infections, sinusitis, otitis media and male infertility. Some patients also have laterality defects. We recently reported the identification of three disease-causing PCD genes in the Irish Traveller population; RSPH4A, DYX1C1 and CCNO. We have since assessed an additional Irish Traveller family with a complex phenotype involving PCD who did not have any of the previously identified PCD mutations.

  10. Mutations in ZMYND10, a gene essential for proper axonemal assembly of inner and outer dynein arms in humans and flies, cause primary ciliary dyskinesia

    DEFF Research Database (Denmark)

    Moore, Daniel J; Onoufriadis, Alexandros; Shoemark, Amelia;

    2013-01-01

    Primary ciliary dyskinesia (PCD) is a ciliopathy characterized by airway disease, infertility, and laterality defects, often caused by dual loss of the inner dynein arms (IDAs) and outer dynein arms (ODAs), which power cilia and flagella beating. Using whole-exome and candidate-gene Sanger resequ...

  11. Analysis of Axonemal Assembly During Ciliary Regeneration in Chlamydomonas.

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    Hunter, Emily L; Sale, Winfield S; Alford, Lea M

    2016-01-01

    Chlamydomonas reinhardtii is an outstanding model genetic organism for study of assembly of cilia. Here, methods are described for synchronization of ciliary regeneration in Chlamydomonas to analyze the sequence in which ciliary proteins assemble. In addition, the methods described allow analysis of the mechanisms involved in regulation of ciliary length, the proteins required for ciliary assembly, and the temporal expression of genes encoding ciliary proteins. Ultimately, these methods can contribute to discovery of conserved genes that when defective lead to abnormal ciliary assembly and human disease. PMID:27514926

  12. Genome-wide transcriptional analysis of flagellar regeneration in Chlamydomonas reinhardtii identifies orthologs of ciliary disease genes

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    Stolc, Viktor; Samanta, Manoj Pratim; Tongprasit, Waraporn; Marshall, Wallace F.

    2005-01-01

    The important role that cilia and flagella play in human disease creates an urgent need to identify genes involved in ciliary assembly and function. The strong and specific induction of flagellar-coding genes during flagellar regeneration in Chlamydomonas reinhardtii suggests that transcriptional profiling of such cells would reveal new flagella-related genes. We have conducted a genome-wide analysis of RNA transcript levels during flagellar regeneration in Chlamydomonas by using maskless photolithography method-produced DNA oligonucleotide microarrays with unique probe sequences for all exons of the 19,803 predicted genes. This analysis represents previously uncharacterized whole-genome transcriptional activity profiling study in this important model organism. Analysis of strongly induced genes reveals a large set of known flagellar components and also identifies a number of important disease-related proteins as being involved with cilia and flagella, including the zebrafish polycystic kidney genes Qilin, Reptin, and Pontin, as well as the testis-expressed tubby-like protein TULP2.

  13. Genomic organization and chromosomal localization of the human and mouse genes encoding the {alpha} receptor component for ciliary neurotrophic factor

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    Valenzuela, D.M.; Rojas, E.; McClain, J. [Regeneron Pharmaceuticals, Inc., Tarrytown, NY (United States)] [and others

    1995-01-01

    Ciliary neurotrophic factor (CNTF) has recently been found to share receptor components with, and to be structurally related to, a family of broadly acting cytokines, including interleukin-6, leukemia inhibitory factor, and oncostatin M. However, the CNTF receptor complex also includes a CNTF-specific component known as CNTF receptor {alpha} (CNTFR{alpha}). Here we describe the molecular cloning of the human and mouse genes encoding CNTFR. We report that the human and mouse genes have an identical intron-exon structure that correlates well with the domain structure of CNTFR{alpha}. That is, the signal peptide and the immunoglobulin-like domain are each encoded by single exons, the cytokine receptor-like domain is distributed among 4 exons, and the C-terminal glycosyl phosphatidylinositol recognition domain in encoded by the final coding exon. The position of the introns within the cytokine receptor-like domain corresponds to those found in other members of the cytokine receptor superfamily. Confirming a recent study using radiation hybrids, we have also mapped the human CNTFR gene to chromosome band 9p13 and the mouse gene to a syntenic region of chromosome 4. 24 refs., 4 figs.

  14. The gene of ciliary neurotrophic factor (cntf) maps to murine chromosome 19 and its expression is not affected in the hereditary motoneuron disease 'wobbler' of the mouse

    OpenAIRE

    Kaupmann, Klemens; Sendtner, Michael; Stöckli, Kurt A.; Jockusch, Harald

    2010-01-01

    The cDNA for ciliary neurotrophic factor (CNTF), a polypeptide involved in the survival of motoneurons in mammals, has recently been cloned (Stöckli et al., Nature, 342, 920 - 923, 1989; Lin et al. Science, 246, 1023 - 1025, 1989). We have now localized the corresponding gene Cntf to chromosome 19 in the mouse, using an interspecific cross between Mus spretus and Mus musculus domesticus. The latter was carrying the gene wobbler (wr) for spinal muscular atrophy. DNA was prepared from backcross...

  15. Primary ciliary dyskinesia.

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    Lobo, Jason; Zariwala, Maimoona A; Noone, Peadar G

    2015-04-01

    Primary ciliary dyskinesia (PCD) is an autosomal recessive disorder of cilia structure, function, and biogenesis leading to chronic infections of the respiratory tract, fertility problems, and disorders of organ laterality. The diagnosis can be challenging, using traditional tools such as characteristic clinical features, ciliary function, and ultrastructural defects and newer screening tools such as nasal nitric oxide levels and genetic testing add to the diagnostic algorithm. There are 32 known PCD-causing genes, and in the future, comprehensive genetic testing may screen young infants before developing symptoms, thus improving survival. Therapies include surveillance of pulmonary function and microbiology, in addition to airway clearance, antibiotics, and early referral to bronchiectasis centers. As with cystic fibrosis (CF), standardized care at specialized centers using a multidisciplinary approach likely improves outcomes. In conjunction with the CF foundation, the PCD foundation, with experienced investigators and clinicians, is developing a network of PCD clinical centers to coordinate the effort in North America and Europe. As the network grows, clinical care and knowledge will improve. PMID:25826585

  16. Ciliary neurotrophic factor induces genes associated with inflammation and gliosis in the retina: a gene profiling study of flow-sorted, Muller cells.

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    Wei Xue

    Full Text Available BACKGROUND: Ciliary neurotrophic factor (CNTF, a member of the interleukin-6 cytokine family, has been implicated in the development, differentiation and survival of retinal neurons. The mechanisms of CNTF action as well as its cellular targets in the retina are poorly understood. It has been postulated that some of the biological effects of CNTF are mediated through its action via retinal glial cells; however, molecular changes in retinal glia induced by CNTF have not been elucidated. We have, therefore, examined gene expression dynamics of purified Müller (glial cells exposed to CNTF in vivo. METHODOLOGY/PRINCIPAL FINDINGS: Müller cells were flow-sorted from mgfap-egfp transgenic mice one or three days after intravitreal injection of CNTF. Microarray analysis using RNA from purified Müller cells showed differential expression of almost 1,000 transcripts with two- to seventeen-fold change in response to CNTF. A comparison of transcriptional profiles from Müller cells at one or three days after CNTF treatment showed an increase in the number of transcribed genes as well as a change in the expression pattern. Ingenuity Pathway Analysis showed that the differentially regulated genes belong to distinct functional types such as cytokines, growth factors, G-protein coupled receptors, transporters and ion channels. Interestingly, many genes induced by CNTF were also highly expressed in reactive Müller cells from mice with inherited or experimentally induced retinal degeneration. Further analysis of gene profiles revealed 20-30% overlap in the transcription pattern among Müller cells, astrocytes and the RPE. CONCLUSIONS/SIGNIFICANCE: Our studies provide novel molecular insights into biological functions of Müller glial cells in mediating cytokine response. We suggest that CNTF remodels the gene expression profile of Müller cells leading to induction of networks associated with transcription, cell cycle regulation and inflammatory response. CNTF

  17. Mutations in GAS8, a Gene Encoding a Nexin-Dynein Regulatory Complex Subunit, Cause Primary Ciliary Dyskinesia with Axonemal Disorganization.

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    Jeanson, Ludovic; Thomas, Lucie; Copin, Bruno; Coste, André; Sermet-Gaudelus, Isabelle; Dastot-Le Moal, Florence; Duquesnoy, Philippe; Montantin, Guy; Collot, Nathalie; Tissier, Sylvie; Papon, Jean-François; Clement, Annick; Louis, Bruno; Escudier, Estelle; Amselem, Serge; Legendre, Marie

    2016-08-01

    Primary ciliary dyskinesia (PCD) is an autosomal recessive disease characterized by chronic respiratory infections of the upper and lower airways, hypofertility, and, in approximately half of the cases, situs inversus. This complex phenotype results from defects in motile cilia and sperm flagella. Among the numerous genes involved in PCD, very few-including CCDC39 and CCDC40-carry mutations that lead to a disorganization of ciliary axonemes with microtubule misalignment. Focusing on this particular phenotype, we identified bi-allelic loss-of-function mutations in GAS8, a gene that encodes a subunit of the nexin-dynein regulatory complex (N-DRC) orthologous to DRC4 of the flagellated alga Chlamydomonas reinhardtii. Unlike the majority of PCD patients, individuals with GAS8 mutations have motile cilia, which, as documented by high-speed videomicroscopy, display a subtle beating pattern defect characterized by slightly reduced bending amplitude. Immunofluorescence studies performed on patients' respiratory cilia revealed that GAS8 is not required for the proper expression of CCDC39 and CCDC40. Rather, mutations in GAS8 affect the subcellular localization of another N-DRC subunit called DRC3. Overall, this study, which identifies GAS8 as a PCD gene, unveils the key importance of the corresponding protein in N-DRC integrity and in the proper alignment of axonemal microtubules in humans. PMID:27120127

  18. Use of suppression subtractive hybridization to identify genes regulated by ciliary neurotrophic factor in postnatal retinal explants

    OpenAIRE

    Roger, Jérôme; Goureau, Olivier; Sahel, José-Alain; Guillonneau, Xavier

    2007-01-01

    Purpose The retinal progenitors are multipotential, and the decision taken by a progenitor to differentiate along a particular path depends on both cell-intrinsic and cell-extrinsic factors. Ciliary neurotrophic factor (CNTF), a member of the interleukin-6 (IL-6) family, added to rat postnatal retinal progenitors inhibits rod photoreceptor cell differentiation, promotes Müller glia genesis and enhances the expression of bipolar neuron markers. We hypothesized that those transcripts regulated ...

  19. A speciation gene for left-right reversal in snails results in anti-predator adaptation.

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    Hoso, Masaki; Kameda, Yuichi; Wu, Shu-Ping; Asami, Takahiro; Kato, Makoto; Hori, Michio

    2010-01-01

    How speciation genes can spread in a population is poorly understood. In land snails, a single gene for left-right reversal could be responsible for instant speciation, because dextral and sinistral snails have difficulty in mating. However, the traditional two-locus speciation model predicts that a mating disadvantage for the reversal should counteract this speciation. In this study, we show that specialized snake predation of the dextral majority drives prey speciation by reversal. Our experiments demonstrate that sinistral Satsuma snails (Stylommatophora: Camaenidae) survive predation by Pareas iwasakii (Colubroidea: Pareatidae). Worldwide biogeography reveals that stylommatophoran snail speciation by reversal has been accelerated in the range of pareatid snakes, especially in snails that gain stronger anti-snake defense and reproductive isolation from dextrals by sinistrality. Molecular phylogeny of Satsuma snails further provides intriguing evidence of repetitive speciation under snake predation. Our study demonstrates that a speciation gene can be fixed in populations by positive pleiotropic effects on survival. PMID:21139578

  20. Programming of stress-related behavior and epigenetic neural gene regulation in mice offspring through maternal exposure to predator odor

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    Sophie St-Cyr

    2015-06-01

    Full Text Available Perinatal stress mediated through the mother can lead to long-term alterations in stress-related phenotypes in offspring. The capacity for adaptation to adversity in early life depends in part of the life history of the animal. This study was designed to examine the behavioral and neural response in adult offspring to prenatal exposure to predator odor: an ethologically-relevant psychological stressor. Pregnant mice were exposed daily to predator odors or distilled water control over the second half of the pregnancy. Predator odor exposure lead to a transient decrease in maternal care in the mothers. As adults, the offspring of predator odor-exposed mothers showed increased anti-predator behavior and predator-odor induced decrease in activity, in female offspring, an increased corticosterone response to predator odor exposure. We found a highly specific response among stress-related genes within limbic brain regions. Transcript abundance of CRHR1 (Corticotropin-releasing hormone receptor 1 was elevated in the amygdala in female offspring of predator odor-exposed dams. In the hippocampus of adult female offspring, decreased BDNF (Brain-derived neurotrophic factor gene expression was correlated with a site-specific decrease in DNA methylation in the Bdnf exon IV, indicating the potential contribution of this epigenetic mechanism to maternal programming by prenatal predator odor exposure. These data indicate that prenatal predator odor exposure alone is sufficient to induce an altered stress-related phenotype in adulthood, with implications for anti-predator behavior in offspring.

  1. Pseudotumor of Ciliary Body

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    Mary Varghese

    2014-01-01

    Full Text Available Orbital pseudotumor is a benign disease involving the orbital structures. Pseudotumor of the ciliary body is rare. We present a case of a 27-year-old male who presented with gradual visual loss, pain, and redness in his left eye. On examination he was found to have a yellowish white mass at the periphery of anterior chamber in his left eye and ultrasound biomicroscopy (UBM revealed a ciliary body mass in the same eye. He was treated with systemic steroids, which was tapered over a period of 8 weeks. His symptoms improved and the ciliary body mass disappeared with no recurrence over the next 6 months. UBM is an important diagnostic tool for diagnosing ciliary body mass. Early diagnosis and prompt treatment with systemic steroids may help resolve pseudotumor of the ciliary body.

  2. Gene up-regulation in response to predator kairomones in the water flea, Daphnia pulex

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    Okada Yasukazu

    2010-04-01

    Full Text Available Abstract Background Numerous cases of predator-induced polyphenisms, in which alternate phenotypes are produced in response to extrinsic stimuli, have been reported in aquatic taxa to date. The genus Daphnia (Branchiopoda, Cladocera provides a model experimental system for the study of the developmental mechanisms and evolutionary processes associated with predator-induced polyphenisms. In D. pulex, juveniles form neckteeth in response to predatory kairomones released by Chaoborus larvae (Insecta, Diptera. Results Previous studies suggest that the timing of the sensitivity to kairomones in D. pulex can generally be divided into the embryonic and postembryonic developmental periods. We therefore examined which of the genes in the embryonic and first-instar juvenile stages exhibit different expression levels in the presence or absence of predator kairomones. Employing a candidate gene approach and identifying differentially-expressed genes revealed that the morphogenetic factors, Hox3, extradenticle and escargot, were up-regulated by kairomones in the postembryonic stage and may potentially be responsible for defense morph formation. In addition, the juvenile hormone pathway genes, JHAMT and Met, and the insulin signaling pathway genes, InR and IRS-1, were up-regulated in the first-instar stage. It is well known that these hormonal pathways are involved in physiological regulation following morphogenesis in many insect species. During the embryonic stage when morphotypes were determined, one of the novel genes identified by differential display was up-regulated, suggesting that this gene may be related to morphotype determination. Biological functions of the up-regulated genes are discussed in the context of defense morph formation. Conclusions It is suggested that, following the reception of kairomone signals, the identified genes are involved in a series of defensive phenotypic alterations and the production of a defensive phenotype.

  3. Rat ciliary neurotrophic factor (CNTF)

    OpenAIRE

    Carroll, P.; Sendtner, M.; Meyer, Michael; Thoenen, Hans

    1993-01-01

    The structure of the rat ciliary neurotrophic factor (CNTF) gene and the regulation of CNTF mRNA levels in cultured glial cells were investigated. The rat mRNA is encoded by a simple two-exon transcription unit. Sequence analysis of the region upstream of the transcription start-site did not reveal a typical TATA-box consensus sequence. Low levels of CNTF mRNA were detected in cultured Schwann cells, and CNTF mRNA was not increased by a variety of treatments. Three-week-old astrocyte-enriched...

  4. Ciliary Neurotrophic Factor Induces Genes Associated with Inflammation and Gliosis in the Retina: A Gene Profiling Study of Flow-Sorted, Müller Cells

    OpenAIRE

    Xue, Wei; Cojocaru, Radu I.; Dudley, V. Joseph; Brooks, Matthew; Swaroop, Anand; Sarthy, Vijay P.

    2011-01-01

    Background Ciliary neurotrophic factor (CNTF), a member of the interleukin-6 cytokine family, has been implicated in the development, differentiation and survival of retinal neurons. The mechanisms of CNTF action as well as its cellular targets in the retina are poorly understood. It has been postulated that some of the biological effects of CNTF are mediated through its action via retinal glial cells; however, molecular changes in retinal glia induced by CNTF have not been elucidated. We hav...

  5. Primary Ciliary Dyskinesia.

    Science.gov (United States)

    Knowles, Michael R; Zariwala, Maimoona; Leigh, Margaret

    2016-09-01

    Primary ciliary dyskinesia (PCD) is a recessive genetically heterogeneous disorder of motile cilia with chronic otosinopulmonary disease and organ laterality defects in ∼50% of cases. The prevalence of PCD is difficult to determine. Recent diagnostic advances through measurement of nasal nitric oxide and genetic testing has allowed rigorous diagnoses and determination of a robust clinical phenotype, which includes neonatal respiratory distress, daily nasal congestion, and wet cough starting early in life, along with organ laterality defects. There is early onset of lung disease in PCD with abnormal airflow mechanics and radiographic abnormalities detected in infancy and early childhood. PMID:27514592

  6. The Andromonoecious Sex Determination Gene Predates the Separation of Cucumis and Citrullus Genera

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    Boualem, Adnane; Lemhemdi, Afef; Sari, Marie-Agnes; Pignoly, Sarah; Troadec, Christelle; Abou Choucha, Fadi; Solmaz, Ilknur; Sari, Nebahat; Dogimont, Catherine; Bendahmane, Abdelhafid

    2016-01-01

    Understanding the evolution of sex determination in plants requires the cloning and the characterization of sex determination genes. Monoecy is characterized by the presence of both male and female flowers on the same plant. Andromonoecy is characterized by plants carrying both male and bisexual flowers. In watermelon, the transition between these two sexual forms is controlled by the identity of the alleles at the A locus. We previously showed, in two Cucumis species, melon and cucumber, that the transition from monoecy to andromonoecy results from mutations in 1-aminocyclopropane-1-carboxylic acid synthase (ACS) gene, ACS-7/ACS2. To test whether the ACS-7/ACS2 function is conserved in cucurbits, we cloned and characterized ClACS7 in watermelon. We demonstrated co-segregation of ClACS7, the homolog of CmACS-7/CsACS2, with the A locus. Sequence analysis of ClACS7 in watermelon accessions identified three ClACS7 isoforms, two in andromonoecious and one in monoecious lines. To determine whether the andromonoecious phenotype is due to a loss of ACS enzymatic activity, we expressed and assayed the activity of the three protein isoforms. Like in melon and cucumber, the isoforms from the andromonoecious lines showed reduced to no enzymatic activity and the isoform from the monoecious line was active. Consistent with this, the mutations leading andromonoecy were clustered in the active site of the enzyme. Based on this, we concluded that active ClACS7 enzyme leads to the development of female flowers in monoecious lines, whereas a reduction of enzymatic activity yields hermaphrodite flowers. ClACS7, like CmACS-7/CsACS2 in melon and cucumber, is highly expressed in carpel primordia of buds determined to develop carpels and not in male flowers. Based on this finding and previous investigations, we concluded that the monoecy gene, ACS7, likely predated the separation of the Cucumis and Citrullus genera. PMID:27171236

  7. Conservation of ciliary proteins in plants with no cilia

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    Hodges Matthew E

    2011-12-01

    Full Text Available Abstract Background Eukaryotic cilia are complex, highly conserved microtubule-based organelles with a broad phylogenetic distribution. Cilia were present in the last eukaryotic common ancestor and many proteins involved in cilia function have been conserved through eukaryotic diversification. However, cilia have also been lost multiple times in different lineages, with at least two losses occurring within the land plants. Whereas all non-seed plants produce cilia for motility of male gametes, some gymnosperms and all angiosperms lack cilia. During these evolutionary losses, proteins with ancestral ciliary functions may be lost or co-opted into different functions. Results Here we identify a core set of proteins with an inferred ciliary function that are conserved in ciliated eukaryotic species. We interrogate this genomic dataset to identify proteins with a predicted ancestral ciliary role that have been maintained in non-ciliated land plants. In support of our prediction, we demonstrate that several of these proteins have a flagellar localisation in protozoan trypanosomes. The phylogenetic distribution of these genes within the land plants indicates evolutionary scenarios of either sub- or neo-functionalisation and expression data analysis shows that these genes are highly expressed in Arabidopsis thaliana pollen cells. Conclusions A large number of proteins possess a phylogenetic ciliary profile indicative of ciliary function. Remarkably, many genes with an ancestral ciliary role are maintained in non-ciliated land plants. These proteins have been co-opted to perform novel functions, most likely before the loss of cilia, some of which appear related to the formation of the male gametes.

  8. Optimal ciliary beating patterns

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    Vilfan, Andrej; Osterman, Natan

    2011-11-01

    We introduce a measure for energetic efficiency of single or collective biological cilia. We define the efficiency of a single cilium as Q2 / P , where Q is the volume flow rate of the pumped fluid and P is the dissipated power. For ciliary arrays, we define it as (ρQ) 2 / (ρP) , with ρ denoting the surface density of cilia. We then numerically determine the optimal beating patterns according to this criterion. For a single cilium optimization leads to curly, somewhat counterintuitive patterns. But when looking at a densely ciliated surface, the optimal patterns become remarkably similar to what is observed in microorganisms like Paramecium. The optimal beating pattern then consists of a fast effective stroke and a slow sweeping recovery stroke. Metachronal waves lead to a significantly higher efficiency than synchronous beating. Efficiency also increases with an increasing density of cilia up to the point where crowding becomes a problem. We finally relate the pumping efficiency of cilia to the swimming efficiency of a spherical microorganism and show that the experimentally estimated efficiency of Paramecium is surprisingly close to the theoretically possible optimum.

  9. Ciliary and non-ciliary expression and function of PACRG during vertebrate development

    Directory of Open Access Journals (Sweden)

    Thumberger Thomas

    2012-08-01

    Full Text Available Abstract Background Park2-co-regulated gene (PACRG is evolutionarily highly conserved from green algae to mammals. In Chlamydomonas and trypanosomes, the PACRG protein associates with flagella. Loss of PACRG results in shortened or absent flagella. In mouse the PACRG protein is required for spermatogenesis. The purpose of the present study was to analyze (1 the expression patterns of PACRG during vertebrate embryogenesis, and (2 whether the PACRG protein was required for left-right (LR axis specification through cilia-driven leftward flow in Xenopus laevis. Methods PACRG cDNAs were cloned and expression was analyzed during early embryonic development of Xenopus, mouse, rabbit and zebrafish. Antisense morpholino oligonucleotide (MO mediated gene knockdown was applied in Xenopus to investigate LR development at the level of tissue morphology, leftward flow and asymmetric marker gene expression, using timelapse videography, scanning electron microscopy (SEM and whole-mount in situ hybridization. Results were statistically evaluated using Wilcoxon paired and χ2 tests. Results PACRG mRNA expression was found in cells and tissues harboring cilia throughout the vertebrates. Highly localized expression was also detected in the brain. During early development, PACRG was specifically localized to epithelia where leftward flow arises, that is, the gastrocoel roof plate (GRP in Xenopus, the posterior notochord (PNC in mammals and Kupffer’s vesicle (KV in zebrafish. Besides its association with ciliary axonemes, subcellular localization of PACRG protein was found around the nucleus and in a spotty pattern in the cytoplasm. A green fluorescent protein (GFP fusion construct preferentially labeled cilia, rendering PACRG a versatile marker for live imaging. Loss-of-function in the frog resulted dose dependently in LR, neural tube closure and gastrulation defects, representing ciliary and non-ciliary functions of PACRG. Conclusions The PACRG protein is a novel

  10. Ciliary photoreceptors in the cerebral eyes of a protostome larva

    Directory of Open Access Journals (Sweden)

    Passamaneck Yale J

    2011-03-01

    Full Text Available Abstract Background Eyes in bilaterian metazoans have been described as being composed of either ciliary or rhabdomeric photoreceptors. Phylogenetic distribution, as well as distinct morphologies and characteristic deployment of different photopigments (ciliary vs. rhabdomeric opsins and transduction pathways argue for the co-existence of both of these two photoreceptor types in the last common bilaterian ancestor. Both receptor types exist throughout the Bilateria, but only vertebrates are thought to use ciliary photoreceptors for directional light detection in cerebral eyes, while all other invertebrate bilaterians studied utilize rhabdomeric photoreceptors for this purpose. In protostomes, ciliary photoreceptors that express c-opsin have been described only from a non-visual deep-brain photoreceptor. Their homology with vertebrate rods and cones of the human eye has been hypothesized to represent a unique functional transition from non-visual to visual roles in the vertebrate lineage. Results To test the hypothesis that protostome cerebral eyes employ exclusively rhabdomeric photoreceptors, we investigated the ultrastructure of the larval eyes in the brachiopod Terebratalia transversa. We show that these pigment-cup eyes consist of a lens cell and a shading pigment cell, both of which are putative photoreceptors, deploying a modified, enlarged cilium for light perception, and have axonal connections to the larval brain. Our investigation of the gene expression patterns of c-opsin, Pax6 and otx in these eyes confirms that the larval eye spots of brachiopods are cerebral eyes that deploy ciliary type photoreceptors for directional light detection. Interestingly, c-opsin is also expressed during early embryogenesis in all potential apical neural cells, becoming restricted to the anterior neuroectoderm, before expression is initiated in the photoreceptor cells of the eyes. Coincident with the expression of c-opsin in the presumptive neuroectoderm

  11. Ciliary ultrastructure of polyplacophorans (Mollusca, Amphineura, Polyplacophora).

    Science.gov (United States)

    Lundin, K; Schander, C

    2001-01-01

    This study is part of a series of papers aiming to investigate the phylogenetic significance of ciliary ultrastructure among molluscs and to test the hypothesis of a relationship between Xenoturbella and the molluscs. The ultrastructure of the ciliary apparatus on the gills of the polyplacophorans Leptochiton asellus and Tonicella rubra was studied. The gill cilia of the two species are similar in shape. The free part of the cilium is long with a slender distal part. There are two ciliary rootlets. One of them is short, broad and placed on the anterior face of the basal body. The other rootlet is conical and has a vertical orientation. Among the mollusca, two ciliary rootlets in the ciliary apparatus of multiciliate ectodermal cells have only been reported from the Chaetodermomorpha and Neomeniomorpha. This character state is likely plesiomorphic for the Mollusca and indicates a basal (nonderived) position of these taxa among the molluscs. No possible synapomorphic character with Xenoturbella bocki was found. PMID:11686414

  12. Deficit of mitonuclear genes on the human X chromosome predates sex chromosome formation.

    Science.gov (United States)

    Dean, Rebecca; Zimmer, Fabian; Mank, Judith E

    2015-02-01

    Two taxa studied to date, the therian mammals and Caenorhabditis elegans, display underrepresentations of mitonuclear genes (mt-N genes, nuclear genes whose products are imported to and act within the mitochondria) on their X chromosomes. This pattern has been interpreted as the result of sexual conflict driving mt-N genes off of the X chromosome. However, studies in several other species have failed to detect a convergent biased distribution of sex-linked mt-N genes, leading to questions over the generality of the role of sexual conflict in shaping the distribution of mt-N genes. Here we tested whether mt-N genes moved off of the therian X chromosome following sex chromosome formation, consistent with the role of sexual conflict, or whether the paucity of mt-N genes on the therian X is a chance result of an underrepresentation on the ancestral regions that formed the X chromosome. We used a synteny-based approach to identify the ancestral regions in the platypus and chicken genomes that later formed the therian X chromosome. We then quantified the movement of mt-N genes on and off of the X chromosome and the distribution of mt-N genes on the human X and ancestral X regions. We failed to find an excess of mt-N gene movement off of the X. The bias of mt-N genes on ancestral therian X chromosomes was also not significantly different from the biases on the human X. Together our results suggest that, rather than conflict driving mt-N genes off of the mammalian X, random biases on chromosomes that formed the X chromosome could explain the paucity of mt-N genes in the therian lineage. PMID:25637223

  13. Up to date on primary ciliary dyskinesia in children.

    Science.gov (United States)

    Pifferi, Massimo; Di Cicco, Maria; Piras, Martina; Cangiotti, Angela M; Saggese, Giuseppe

    2013-10-01

    Primary ciliary dyskinesia (PCD) is a congenital, clinically and ultrastructurally heterogeneous disease due to abnormal structure and/or function of cilia, with impaired mucociliary transport leading to several respiratory disorders. PCD can be diagnosed by the combination of thorough clinical examination with functional and ultrastructural analysis of the cilia. This paper shows progresses in PCD diagnosis obtained by ciliogenesis in culture evaluation of ciliated respiratory cells and by genetic analysis of mutations in candidate genes. Moreover, since to date no specific treatments are available to correct the ciliary dysfunction, the paper shows the proper therapeutical approach by the use of respiratory physiotherapy and regular exercise to favour airways clearance, by antibiotics administration to control acute airway infections. Macrolides administration as antiinflammatory option is suggested. PMID:23973004

  14. Feather development genes and associated regulatory innovation predate the origin of Dinosauria

    OpenAIRE

    Lowe, Craig B.; Clarke, Julia A.; Baker, Allan J.; Haussler, D.; Edwards, Scott V.

    2014-01-01

    The evolution of avian feathers have recently been illuminated by fossils and the identification of genes involved in feather patterning and morphogenesis. However, molecular studies have focused mainly on protein-coding genes. Using comparative genomics and more than 600,000 conserved regulatory elements, we show that patterns of genome evolution in the vicinity of feather genes are consistent with a major role for regulatory innovation in the evolution of feathers. Rates of innovation at fe...

  15. Feather Development Genes and Associated Regulatory Innovation Predate the Origin of Dinosauria

    OpenAIRE

    Lowe, Craig B.; Clarke, Julia A.; Baker, Allan J.; Haussler, David; Edwards, Scott V.

    2014-01-01

    The evolution of avian feathers has recently been illuminated by fossils and the identification of genes involved in feather patterning and morphogenesis. However, molecular studies have focused mainly on protein-coding genes. Using comparative genomics and more than 600,000 conserved regulatory elements, we show that patterns of genome evolution in the vicinity of feather genes are consistent with a major role for regulatory innovation in the evolution of feathers. Rates of innovation at fea...

  16. Predator-induced defences in Daphnia pulex: Selection and evaluation of internal reference genes for gene expression studies with real-time PCR

    Directory of Open Access Journals (Sweden)

    Gilbert Don

    2010-06-01

    Full Text Available Abstract Background The planktonic microcrustacean Daphnia pulex is among the best-studied animals in ecological, toxicological and evolutionary research. One aspect that has sustained interest in the study system is the ability of D. pulex to develop inducible defence structures when exposed to predators, such as the phantom midge larvae Chaoborus. The available draft genome sequence for D. pulex is accelerating research to identify genes that confer plastic phenotypes that are regularly cued by environmental stimuli. Yet for quantifying gene expression levels, no experimentally validated set of internal control genes exists for the accurate normalization of qRT-PCR data. Results In this study, we tested six candidate reference genes for normalizing transcription levels of D. pulex genes; alpha tubulin (aTub, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, TATA box binding protein (Tbp syntaxin 16 (Stx16, X-box binding protein 1 (Xbp1 and CAPON, a protein associated with the neuronal nitric oxide synthase, were selected on the basis of an earlier study and from microarray studies. One additional gene, a matrix metalloproteinase (MMP, was tested to validate its transcriptional response to Chaoborus, which was earlier observed in a microarray study. The transcription profiles of these seven genes were assessed by qRT-PCR from RNA of juvenile D. pulex that showed induced defences in comparison to untreated control animals. We tested the individual suitability of genes for expression normalization using the programs geNorm, NormFinder and BestKeeper. Intriguingly, Xbp1, Tbp, CAPON and Stx16 were selected as ideal reference genes. Analyses on the relative expression level using the software REST showed that both classical housekeeping candidate genes (aTub and GAPDH were significantly downregulated, whereas the MMP gene was shown to be significantly upregulated, as predicted. aTub is a particularly ill suited reference gene because five copies are

  17. Feather development genes and associated regulatory innovation predate the origin of Dinosauria.

    Science.gov (United States)

    Lowe, Craig B; Clarke, Julia A; Baker, Allan J; Haussler, David; Edwards, Scott V

    2015-01-01

    The evolution of avian feathers has recently been illuminated by fossils and the identification of genes involved in feather patterning and morphogenesis. However, molecular studies have focused mainly on protein-coding genes. Using comparative genomics and more than 600,000 conserved regulatory elements, we show that patterns of genome evolution in the vicinity of feather genes are consistent with a major role for regulatory innovation in the evolution of feathers. Rates of innovation at feather regulatory elements exhibit an extended period of innovation with peaks in the ancestors of amniotes and archosaurs. We estimate that 86% of such regulatory elements and 100% of the nonkeratin feather gene set were present prior to the origin of Dinosauria. On the branch leading to modern birds, we detect a strong signal of regulatory innovation near insulin-like growth factor binding protein (IGFBP) 2 and IGFBP5, which have roles in body size reduction, and may represent a genomic signature for the miniaturization of dinosaurian body size preceding the origin of flight. PMID:25415961

  18. Quantitative optical coherence tomography imaging of intermediate flow defect phenotypes in ciliary physiology and pathophysiology

    Science.gov (United States)

    Huang, Brendan K.; Gamm, Ute A.; Jonas, Stephan; Khokha, Mustafa K.; Choma, Michael A.

    2015-03-01

    Cilia-driven fluid flow is a critical yet poorly understood aspect of pulmonary physiology. Here, we demonstrate that optical coherence tomography-based particle tracking velocimetry can be used to quantify subtle variability in cilia-driven flow performance in Xenopus, an important animal model of ciliary biology. Changes in flow performance were quantified in the setting of normal development, as well as in response to three types of perturbations: mechanical (increased fluid viscosity), pharmacological (disrupted serotonin signaling), and genetic (diminished ciliary motor protein expression). Of note, we demonstrate decreased flow secondary to gene knockdown of kif3a, a protein involved in ciliogenesis, as well as a dose-response decrease in flow secondary to knockdown of dnah9, an important ciliary motor protein.

  19. Primary ciliary dyskinesia: clinical and genetic aspects

    Directory of Open Access Journals (Sweden)

    E. D’Auria

    2012-06-01

    Full Text Available Primary ciliary dyskinesia (PCD is a rare, genetically heterogeneous disease, characterized by ciliary disfunction and impaired mucociliary clearance, resulting in a range of clinical manifestations such as chronic bronchitis, bronchiectasis, chronic rhino-sinusitis, chronic otitis media, situs viscerum inversus in almost 40-50% of cases and male infertility. The triad situs viscerum inversus, bronchiectasis and sinusitis is known as Kartagener syndrome. Up to now little is known about genetic, diagnostic and therapeutic aspects of primary motile ciliary diseases in children: for this reason, diagnosis is generally delayed and almost all treatments for PCD are not based on randomized studies but extrapolated from cystic fibrosis guidelines. The aim of this review is to propose to pediatricians a summary of current clinical and diagnostic evidence to obtain better knoledwge of this condition. The earlier diagnosis and the right treatment are both crucial to improve the prognosis of PCD.

  20. Clinical genetics and pathobiology of ciliary chondrodysplasias

    OpenAIRE

    Schmidts, M.

    2014-01-01

    Ciliary chondrodysplasias represent a heterogenous group of rare, nearly exclusively autosomal recessively inherited developmental conditions. While the skeletal phenotype, mainly affecting limbs, ribs and sometimes the craniofacial skeleton, is predominant, extraskeletal disease affecting the kidneys, liver, heart, eyes and other organs and tissues is observed inconsistently. Significant lethality, resulting from cardiorespiratory failure due to thoracic constriction as well as from renal an...

  1. Bacterial Alkaloids Prevent Amoebal Predation.

    Science.gov (United States)

    Klapper, Martin; Götze, Sebastian; Barnett, Robert; Willing, Karsten; Stallforth, Pierre

    2016-07-25

    Bacterial defense mechanisms have evolved to protect bacteria against predation by nematodes, predatory bacteria, or amoebae. We identified novel bacterial alkaloids (pyreudiones A-D) that protect the producer, Pseudomonas fluorescens HKI0770, against amoebal predation. Isolation, structure elucidation, total synthesis, and a proposed biosynthetic pathway for these structures are presented. The generation of P. fluorescens gene-deletion mutants unable to produce pyreudiones rendered the bacterium edible to a variety of soil-dwelling amoebae. PMID:27294402

  2. Vasoactive Intestinal Peptide Induction by Ciliary Neurotrophic Factor in Donor Human Corneal Endothelium in situ

    OpenAIRE

    Koh, Shay-Whey M.; Guo, Yan; Bernstein, Steve L.; Waschek, James A.; Liu, Xiuhuai; Symes, Aviva J

    2007-01-01

    After peripheral nerve axotomy, vasoactive intestinal peptide (VIP) gene expression is upregulated in neurons, whereas ciliary neurotrophic factor (CNTF) accumulates extracellularly at the lesion site. Although CNTF-induced VIP gene expression has been reported in cultured sympathetic neurons and neuroblastoma cells, it still remains to be determined if CNTF and VIP play interrelated roles in nerve injury. The corneal endothelium, like sympathetic neurons, derives from the neural crest. Previ...

  3. Photoreceptor Sensory Cilium: Traversing the Ciliary Gate.

    Science.gov (United States)

    Khanna, Hemant

    2015-01-01

    Cilia are antenna-like extensions of the plasma membrane found in nearly all cell types. In the retina of the eye, photoreceptors develop unique sensory cilia. Not much was known about the mechanisms underlying the formation and function of photoreceptor cilia, largely because of technical limitations and the specific structural and functional modifications that cannot be modeled in vitro. With recent advances in microscopy techniques and molecular and biochemical approaches, we are now beginning to understand the molecular basis of photoreceptor ciliary architecture, ciliary function and its involvement in human diseases. Here, I will discuss the studies that have revealed new knowledge of how photoreceptor cilia regulate their identity and function while coping with high metabolic and trafficking demands associated with processing light signal. PMID:26501325

  4. Photoreceptor Sensory Cilium: Traversing the Ciliary Gate

    Directory of Open Access Journals (Sweden)

    Hemant Khanna

    2015-10-01

    Full Text Available Cilia are antenna-like extensions of the plasma membrane found in nearly all cell types. In the retina of the eye, photoreceptors develop unique sensory cilia. Not much was known about the mechanisms underlying the formation and function of photoreceptor cilia, largely because of technical limitations and the specific structural and functional modifications that cannot be modeled in vitro. With recent advances in microscopy techniques and molecular and biochemical approaches, we are now beginning to understand the molecular basis of photoreceptor ciliary architecture, ciliary function and its involvement in human diseases. Here, I will discuss the studies that have revealed new knowledge of how photoreceptor cilia regulate their identity and function while coping with high metabolic and trafficking demands associated with processing light signal.

  5. Ciliary neurotrophic factor is an endogenous pyrogen.

    OpenAIRE

    Shapiro, L; Zhang, X. X.; Rupp, R G; Wolff, S. M.; Dinarello, C A

    1993-01-01

    Fever is initiated by the action of polypeptide cytokines called endogenous pyrogens, which are produced by the host during inflammation, trauma, or infection and which elevate the thermoregulatory set point in the hypothalamus. Ciliary neurotrophic factor (CNTF) supports the differentiation and survival of central and peripheral neurons. We describe the activity of CNTF as intrinsically pyrogenic in the rabbit. CNTF induced a monophasic fever which rose rapidly (within the first 12 min) foll...

  6. Diagnostic methods in primary ciliary dyskinesia

    OpenAIRE

    Lucas, Jane S; Paff, Tamara; Goggin, Patricia; Haarman, Eric

    2015-01-01

    Diagnosing primary ciliary dyskinesia is difficult. With no reference standard, a combination of tests is needed; most tests require expensive equipment and specialist scientists. We review the advances in diagnostic testing over the past hundred years, with emphasis on recent advances. We particularly focus on use of high-speed video analysis, transmission electron microscopy, nasal nitric oxide and genetic testing. We discuss the international efforts that are in place to advance the eviden...

  7. Diagnostic Methods in Primary Ciliary Dyskinesia.

    Science.gov (United States)

    Lucas, Jane S; Paff, Tamara; Goggin, Patricia; Haarman, Eric

    2016-03-01

    Diagnosing primary ciliary dyskinesia is difficult. With no reference standard, a combination of tests is needed; most tests require expensive equipment and specialist scientists. We review the advances in diagnostic testing over the past hundred years, with emphasis on recent advances. We particularly focus on use of high-speed video analysis, transmission electron microscopy, nasal nitric oxide and genetic testing. We discuss the international efforts that are in place to advance the evidence base for diagnostic tests. PMID:26362507

  8. Gated entry into the ciliary compartment.

    Science.gov (United States)

    Takao, Daisuke; Verhey, Kristen J

    2016-01-01

    Cilia and flagella play important roles in cell motility and cell signaling. These functions require that the cilium establishes and maintains a unique lipid and protein composition. Recent work indicates that a specialized region at the base of the cilium, the transition zone, serves as both a barrier to entry and a gate for passage of select components. For at least some cytosolic proteins, the barrier and gate functions are provided by a ciliary pore complex (CPC) that shares molecular and mechanistic properties with nuclear gating. Specifically, nucleoporins of the CPC limit the diffusional entry of cytosolic proteins in a size-dependent manner and enable the active transport of large molecules and complexes via targeting signals, importins, and the small G protein Ran. For membrane proteins, the septin protein SEPT2 is part of the barrier to entry whereas the gating function is carried out and/or regulated by proteins associated with ciliary diseases (ciliopathies) such as nephronophthisis, Meckel–Gruber syndrome and Joubert syndrome. Here, we discuss the evidence behind these models of ciliary gating as well as the similarities to and differences from nuclear gating. PMID:26472341

  9. Cellular Mechanisms of Ciliary Length Control

    Directory of Open Access Journals (Sweden)

    Jacob Keeling

    2016-01-01

    Full Text Available Cilia and flagella are evolutionarily conserved, membrane-bound, microtubule-based organelles on the surface of most eukaryotic cells. They play important roles in coordinating a variety of signaling pathways during growth, development, cell mobility, and tissue homeostasis. Defects in ciliary structure or function are associated with multiple human disorders called ciliopathies. These diseases affect diverse tissues, including, but not limited to the eyes, kidneys, brain, and lungs. Many processes must be coordinated simultaneously in order to initiate ciliogenesis. These include cell cycle, vesicular trafficking, and axonemal extension. Centrioles play a central role in both cell cycle progression and ciliogenesis, making the transition between basal bodies and mitotic spindle organizers integral to both processes. The maturation of centrioles involves a functional shift from cell division toward cilium nucleation which takes place concurrently with its migration and fusion to the plasma membrane. Several proteinaceous structures of the distal appendages in mother centrioles are required for this docking process. Ciliary assembly and maintenance requires a precise balance between two indispensable processes; so called assembly and disassembly. The interplay between them determines the length of the resulting cilia. These processes require a highly conserved transport system to provide the necessary substances at the tips of the cilia and to recycle ciliary turnover products to the base using a based microtubule intraflagellar transport (IFT system. In this review; we discuss the stages of ciliogenesis as well as mechanisms controlling the lengths of assembled cilia.

  10. Conditional, genetic disruption of ciliary neurotrophic factor receptors reveals a role in adult motor neuron survival

    OpenAIRE

    Lee, Nancy; Robitz, Rachel; Zurbrugg, Rebekah J; Karpman, Adam M; Mahler, Ashley M.; Cronier, Samantha A.; Vesey, Rachel; Spearry, Rachel P.; Zolotukhin, Sergei; MacLennan, A. John

    2008-01-01

    Indirect evidence suggests that endogenous ciliary neurotrophic factor (CNTF) receptor signaling can promote motor neuron (MN) survival in the adult. If so, proper targeting of this signaling may selectively counteract the effects of adult MN diseases. However, direct evidence for CNTF receptor involvement in adult MN survival is lacking, presumably because the unconditional blockade of the mouse CNTF receptor in vivo [through genetic disruption of the essential CNTF receptor α (CNTFRα) gene]...

  11. The relationship between ciliary neurotrophic factor (CNTF) genotype and motor unit physiology: preliminary studies

    OpenAIRE

    Ferrell Robert; Hurley Ben; Roth Stephen; Stashuk Daniel; Ling Shari; Conwit Robin A; Metter E Jeffrey

    2005-01-01

    Abstract Background Ciliary neurotrophic factor (CNTF) is important for neuronal and muscle development, and genetic variation in the CNTF gene has been associated with muscle strength. The effect of CNTF on nerve development suggests that CNTF genotype may be associated with force production via its influence on motor unit size and firing patterns. The purpose of this study is to examine whether CNTF genotype differentially affects motor unit activation in the vastus medialis with increasing...

  12. The Pediatric Choroidal and Ciliary Body Melanoma Study

    DEFF Research Database (Denmark)

    Al-Jamal, Rana'a T; Cassoux, Nathalie; Desjardins, Laurence;

    2016-01-01

    PURPOSE: To collect comprehensive data on choroidal and ciliary body melanoma (CCBM) in children and to validate hypotheses regarding pediatric CCBM: children younger than 18 years, males, and those without ciliary body involvement (CBI) have more favorable survival prognosis than young adults 18...

  13. Artificial ciliary bundles with nano fiber tip links

    CERN Document Server

    Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael

    2015-01-01

    Mechanosensory ciliary bundles in fishes are the inspiration for carefully engineered artificial flow sensors. We report the development of a new class of ultrasensitive MEMS flow sensors that mimic the intricate morphology of the ciliary bundles, including the stereocilia, tip links, and the cupula, and thereby achieve threshold detection limits that match the biological example. An artificial ciliary bundle is achieved by fabricating closely-spaced arrays of polymer micro-pillars with gradiating heights. Tip links that form the fundamental sensing elements are realized through electrospinning aligned PVDF piezoelectric nano-fibers that link the distal tips of the polymer cilia. An optimized synthesis of hyaluronic acid-methacrylic anhydride hydrogel that results in properties close to the biological cupula, together with drop-casting method are used to form the artificial cupula that encapsulates the ciliary bundle. In testing, fluid drag force causes the ciliary bundle to slide, stretching the flexible nan...

  14. Class 1 Integrons Potentially Predating the Association with Tn402-Like Transposition Genes Are Present in a Sediment Microbial Community

    DEFF Research Database (Denmark)

    Stokes, Harold W.; Nesbø, Camilla L.; Holley, Marita;

    2006-01-01

    Integrons are genetic elements that contribute to lateral gene transfer in bacteria as a consequence of possessing a site-specific recombination system. This system facilitates the spread of genes when they are part of mobile cassettes. Most integrons are contained within chromosomes and are...... for bacteria, especially pathogens, which harbor class 1 integrons and their associated antibiotic resistance genes. Here, we have isolated bacteria from soil and sediment in the absence of antibiotic selection. Class 1 integrons were recovered from four different bacterial species not known to be...

  15. HEATR2 plays a conserved role in assembly of the ciliary motile apparatus.

    Directory of Open Access Journals (Sweden)

    Christine P Diggle

    2014-09-01

    Full Text Available Cilia are highly conserved microtubule-based structures that perform a variety of sensory and motility functions during development and adult homeostasis. In humans, defects specifically affecting motile cilia lead to chronic airway infections, infertility and laterality defects in the genetically heterogeneous disorder Primary Ciliary Dyskinesia (PCD. Using the comparatively simple Drosophila system, in which mechanosensory neurons possess modified motile cilia, we employed a recently elucidated cilia transcriptional RFX-FOX code to identify novel PCD candidate genes. Here, we report characterization of CG31320/HEATR2, which plays a conserved critical role in forming the axonemal dynein arms required for ciliary motility in both flies and humans. Inner and outer arm dyneins are absent from axonemes of CG31320 mutant flies and from PCD individuals with a novel splice-acceptor HEATR2 mutation. Functional conservation of closely arranged RFX-FOX binding sites upstream of HEATR2 orthologues may drive higher cytoplasmic expression of HEATR2 during early motile ciliogenesis. Immunoprecipitation reveals HEATR2 interacts with DNAI2, but not HSP70 or HSP90, distinguishing it from the client/chaperone functions described for other cytoplasmic proteins required for dynein arm assembly such as DNAAF1-4. These data implicate CG31320/HEATR2 in a growing intracellular pre-assembly and transport network that is necessary to deliver functional dynein machinery to the ciliary compartment for integration into the motile axoneme.

  16. On ciliary pumping and sieving in bryozoans

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Riisgård, H. U.

    2002-01-01

    result of water currents driven out between tentacles by the water pumping lateral cilia, is characterised by nearly parabolic profiles with highest velocity along the centreline of the lophophore. In intact animals, the centreline velocity first increases from its value at the inlet to a maximal value...... relation between velocity distribution in the lophophore and variation of pumping rate along tentacles. Typical variations are given and compared to those obtained by a more accurate two-dimensional numerical solution. Based on observed velocity distributions in the lophophore, particle tracks and tentacle...... in the absence of a particle. This is hypothesised to stimulate the sensing mechanism triggering observed flicks. The energy cost of pumping is estimated at 1 to 4% of the metabolic power of a "standard" zooid. Keywords: Feeding in bryozoans; Flow in lophophore; Ciliary sieving; Particle retention...

  17. On ciliary pumping and sieving in bryozoans

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Riisgård, H. U.

    result of water currents driven out between tentacles by the water pumping lateral cilia, is characterised by nearly parabolic profiles with highest velocity along the centreline of the lophophore. In intact animals, the centreline velocity first increases from its value at the inlet to a maximal value...... relation between velocity distribution in the lophophore and variation of pumping rate along tentacles. Typical variations are given and compared to those obtained by a more accurate two-dimensional numerical solution. Based on observed velocity distributions in the lophophore, particle tracks and tentacle...... in the absence of a particle. This is hypothesised to stimulate the sensing mechanism triggering observed flicks. The energy cost of pumping is estimated at 1 to 4% of the metabolic power of a "standard" zooid. Keywords: Feeding in bryozoans; Flow in lophophore; Ciliary sieving; Particle retention...

  18. Predation and caribou populations

    Directory of Open Access Journals (Sweden)

    Dale R. Seip

    1991-10-01

    Full Text Available Predation, especially wolf (Canis lupus predation, limits many North American caribou (Rangifer tarandus populations below the density that food resources could sustain. The impact of predation depends on the parameters for the functional and numerical response of the wolves, relative to the potential annual increment of the caribou population. Differences in predator-avoidance strategies largely explain the major differences in caribou densities that occur naturally in North America. Caribou migrations that spatially separate caribou from wolves allow relatively high densities of caribou to survive. Non-migratory caribou that live in areas where wolf populations are sustained by alternate prey can be eliminated by wolf predation.

  19. Diagnosis by ultrastructural study of primary ciliary dyskinesia

    Directory of Open Access Journals (Sweden)

    Melgarejo-Moreno P

    2015-01-01

    Full Text Available Introduction and objective: Primary ciliary dyskinesia (PCD, also known as ciliary immotility (SIC syndrome is an inherited disorder that includes a group of diseases in which respiratory cilia are immobile, ciliary movement is dyskinetic and ineffective or no cilia . The aim of this study is to determine the ciliary ultrastructure in patients with suspected DCP. Method: In 8 patients with suspected DCP nasal mucosa biopsy is performed with endoscopy at the inferior turbinate in the middle third by the ENT service under local anesthesia. Results: Of the 8 cases studied in 2 cases no ciliary ultrastructural level defects were found. In two cases with abnormal ciliary ultrastructure is present Kartagener syndrome. In a case no cilia were observed in the nasal mucosa. Discussion: The DCP and SIC are synonymous terms from clinical and pathogenetic view: immobility and dyskinesia lead to an absence of mucociliary transport, stasis of respiratory secretions with their consequences: chronic infections of lower respiratory tract and from birth . The most common ultrastructural defect is the total or partial absence of dynein. Conclusions: The ultrastructural study allows the diagnosis of PCD because genetic diagnosis is complicated and therefore get an early diagnosis of this condition which serves to improve the morbidity and mortality of these patients.

  20. Col2-Cre recombinase is co-expressed with endogenous type II collagen in embryonic renal epithelium and drives development of polycystic kidney disease following inactivation of ciliary genes

    OpenAIRE

    Kolpakova-Hart, Elona; Nicolae, Claudia; Zhou, Jing; Olsen, Bjorn R

    2008-01-01

    Here we report on the severe defects in renal epithelium induced by the transgenic Col2-Cre line used previously for skeletal tissue-specific gene targeting. We demonstrate that conditional ablation of the Kif3a or Pkd1 genes encoding primary cilium/intraflagellar transport-associated proteins using type II collagen-specific Cre transgenic strain results in a severe form of polycystic kidney disease in mice. We detect Col2-Cre recombinase expression in kidney epithelium, which reflects expres...

  1. Ciliary neurotrophic factor (CNTF) for human retinal degeneration: Phase I trial of CNTF delivered by encapsulated cell intraocular implants

    OpenAIRE

    Sieving, Paul A.; Caruso, Rafael C.; Tao, Weng; Coleman, Hanna R.; Thompson, Darby J. S.; Fullmer, Keri R.; Bush, Ronald A.

    2006-01-01

    Neurotrophic factors are agents with a promising ability to retard progression of neurodegenerative diseases and are effective in slowing photoreceptor degeneration in animal models of retinitis pigmentosa. Here we report a human clinical trial of a neurotrophic factor for retinal neurodegeneration. In this Phase I safety trial, human ciliary neurotrophic factor (CNTF) was delivered by cells transfected with the human CNTF gene and sequestered within capsules that were surgically implanted in...

  2. Expression of ciliary neurotrophic factor (CNTF) and its tripartite receptor complex by cells of the human optic nerve head

    OpenAIRE

    Liu, Xiaochun; Clark, Abbot F.; Wordinger, Robert J.

    2007-01-01

    Purpose Ciliary neurotrophic factor (CNTF) promotes gene expression, cell survival and differentiation in various types of peripheral and central neurons, glia and nonneural cells. The level of CNTF rises rapidly upon injury to neural tissue, suggesting that CNTF exerts its cytoprotective effects after release from cells via mechanisms induced by cell injury. The purpose of this study was to determine if cells in the optic nerve head express CNTF and its tripartite receptor complex. Methods W...

  3. Long-term lentiviral-mediated expression of ciliary neurotrophic factor in the striatum of Huntington's disease transgenic mice

    OpenAIRE

    Zala, Diana; Bensadoun, Jean-Charles; Pereira de Almeida, Luis; Leavitt, Blair R.; Gutekunst, Claire-Anne; Aebischer, Patrick; Hayden, Michael R; Déglon, Nicole

    2004-01-01

    Ciliary neurotrophic factor (CNTF) has been shown to prevent behavioral deficits and striatal degeneration in neurotoxic models of Huntington's disease (HD), but its effect in a genetic model has not been evaluated. Lentiviral vectors expressing the human CNTF or LacZ reporter gene were therefore injected in the striatum of wild-type (WT) and transgenic mice expressing full-length huntingtin with 72 CAG repeats (YAC72). Behavioral analysis showed increased locomotor activity in 5- to 6-month-...

  4. CCDC39 is required for assembly of inner dynein arms and the dynein regulatory complex and for normal ciliary motility in humans and dogs

    DEFF Research Database (Denmark)

    Merveille, Anne-Christine; Davis, Erica E; Becker-Heck, Anita;

    2011-01-01

    -assembly factors of axonemal dyneins, but these mutations account for only about 50% of cases of PCD. We exploited the unique properties of dog populations to positionally clone a new PCD gene, CCDC39. We found that loss-of-function mutations in the human ortholog underlie a substantial fraction of PCD cases with...... axonemal disorganization and abnormal ciliary beating. Functional analyses indicated that CCDC39 localizes to ciliary axonemes and is essential for assembly of inner dynein arms and the dynein regulatory complex....

  5. CFAP54 is required for proper ciliary motility and assembly of the central pair apparatus in mice.

    Science.gov (United States)

    McKenzie, Casey W; Craige, Branch; Kroeger, Tiffany V; Finn, Rozzy; Wyatt, Todd A; Sisson, Joseph H; Pavlik, Jacqueline A; Strittmatter, Lara; Hendricks, Gregory M; Witman, George B; Lee, Lance

    2015-09-15

    Motile cilia and flagella play critical roles in fluid clearance and cell motility, and dysfunction commonly results in the pediatric syndrome primary ciliary dyskinesia (PCD). CFAP221, also known as PCDP1, is required for ciliary and flagellar function in mice and Chlamydomonas reinhardtii, where it localizes to the C1d projection of the central microtubule apparatus and functions in a complex that regulates flagellar motility in a calcium-dependent manner. We demonstrate that the genes encoding the mouse homologues of the other C. reinhardtii C1d complex members are primarily expressed in motile ciliated tissues, suggesting a conserved function in mammalian motile cilia. The requirement for one of these C1d complex members, CFAP54, was identified in a mouse line with a gene-trapped allele. Homozygous mice have PCD characterized by hydrocephalus, male infertility, and mucus accumulation. The infertility results from defects in spermatogenesis. Motile cilia have a structural defect in the C1d projection, indicating that the C1d assembly mechanism requires CFAP54. This structural defect results in decreased ciliary beat frequency and perturbed cilia-driven flow. This study identifies a critical role for CFAP54 in proper assembly and function of mammalian cilia and flagella and establishes the gene-trapped allele as a new model of PCD. PMID:26224312

  6. Progressive hemifacial atrophy with ciliary body atrophy and ocular hypotony

    Directory of Open Access Journals (Sweden)

    T Ashwini Kini

    2015-01-01

    Full Text Available Progressive hemifacial atrophy (PHA is a disease of unknown etiology affecting one-half of the face. Ocular involvement is uncommon. Atrophy of iris is rare, with only a few cases of partial atrophy being reported in the literature. We report a case of total atrophy of iris and ciliary body with associated ocular hypotony in a 16-year-old girl with PHA. We believe this is the first reported case of complete atrophy of iris and ciliary body in PHA. Ocular hypotony in PHA was thought to be due to intra-ocular inflammation. However in our case it appears to be secondary to severe atrophy of the ciliary body.

  7. Angioleiomyoma of the Ciliary Body:A Case Report

    Institute of Scientific and Technical Information of China (English)

    Jianhua Yan; Zhongyao Wu; Yongping Li; Guanguang Feng; Hao Zhang

    2004-01-01

    Purpose: To report a rare case of angioleiomyoma of the ciliary body Methods :The clinical manifestation, imaging findings, histopathologic characteristics were analyzed in a 32-year-old male patient with angioleiomyoma of the ciliary body. Results:The tumor was removed intact with local resection. Histopathologic examination revealed that the tumor was full of vessels and it was composed of spindle cells with abundant cytoplasm. Immunohistochemical studies showed positive for SMA and Desmin and negative for S100 and HMB-45. Conclusions: Angioleiomyoma of the ciliary body is a rare tumor that can be successfully treated with local surgical resection in this area. It needs to be differentiated from other tumors, especially malignant melanoma. Eye Science 2004;20:19-22.

  8. Species diversity modulates predation

    NARCIS (Netherlands)

    Kratina, P.; Vos, M.; Anholt, B.R.

    2007-01-01

    Predation occurs in a context defined by both prey and non-prey species. At present it is largely unknown how species diversity in general, and species that are not included in a predator's diet in particular, modify predator–prey interactions.Therefore we studied how both the density and diversity

  9. The accommodative ciliary muscle function is preserved in older humans

    OpenAIRE

    Tabernero, Juan; Chirre, Emmanuel; Hervella, Lucia; Prieto, Pedro; Artal, Pablo

    2016-01-01

    Presbyopia, the loss of the eye’s accommodation capability, affects all humans aged above 45–50 years old. The two main reasons for this to happen are a hardening of the crystalline lens and a reduction of the ciliary muscle functionality with age. While there seems to be at least some partial accommodating functionality of the ciliary muscle at early presbyopic ages, it is not yet clear whether the muscle is still active at more advanced ages. Previous techniques used to visualize the accomm...

  10. The accommodative ciliary muscle function is preserved in older humans.

    Science.gov (United States)

    Tabernero, Juan; Chirre, Emmanuel; Hervella, Lucia; Prieto, Pedro; Artal, Pablo

    2016-01-01

    Presbyopia, the loss of the eye's accommodation capability, affects all humans aged above 45-50 years old. The two main reasons for this to happen are a hardening of the crystalline lens and a reduction of the ciliary muscle functionality with age. While there seems to be at least some partial accommodating functionality of the ciliary muscle at early presbyopic ages, it is not yet clear whether the muscle is still active at more advanced ages. Previous techniques used to visualize the accommodation mechanism of the ciliary muscle are complicated to apply in the older subjects, as they typically require fixation stability during long measurement times and/or to have an ultrasound probe directly in contact with the eye. Instead, we used our own developed method based on high-speed recording of lens wobbling to study the ciliary muscle activity in a small group of pseudophakic subjects (around 80 years old). There was a significant activity of the muscle, clearly able to contract under binocular stimulation of accommodation. This supports a purely lenticular-based theory of presbyopia and it might stimulate the search for new solutions to presbyopia by making use of the remaining contraction force still presented in the aging eye. PMID:27151778

  11. [A case of primary ciliary dyskinesia who had been treated as asthma].

    Science.gov (United States)

    Hosoki, Koa; Fujisawa, Takao; Masuda, Sawako; Usui, Satoko; Ito, Hiroaki; Nagao, Mizuho; Terada, Akihiko; Iguchi, Kousei; Ogawa, Satoru; Nakatani, Kaname; Takeuchi, Kazuhiko

    2010-07-01

    We report a case of 18-old girl with primary ciliary dyskinesia (PCD) who had been diagnosed as asthma. Since birth, she had presented with unexplained productive cough, sputum, rhinorrhea, and stridor with situs solitus. Her familial history was negative for PCD. At 2 years of age, ciliary beat frequency and beat pattern were normal. She was diagnosed as rhinosinusitis, chronic secretory otitis media. At 3 years of age, she was diagnosed as asthma because of wheezing not associated with respiratory infection. Various asthma medications were then administered, including DSCG, inhaled corticosteroids, and salmeterol, but varying responses to the treatment were noted. Spirometry revealed persistent severe small airway obstruction. Beta2 agonist reversibility was recognized by impulse oscillation system, not with FEV1. At age of 18, chest CT disclosed bronchiectasis, and nasal nitric oxide concentration was very low, 98 ppb and a diagnostic approach for PCD was performed. Electron microscopic analysis of nasal cilia demonstrated defects of the outer and inner dynein arms, and the diagnosis of PCD was made. Mutations in DNAH1 and DNAI1 genes were found. The diagnosis of PCD is often difficult in the absence of situs inversus totalis. Recurrent wheeze with chronic rhinosinusitis, chronic otitis media, and brochiectasis may warrant detailed investigations for PCD, especially with nasal NO measurement. PMID:20703071

  12. The presence of synaptic and chromosome disjunction mutants in Cenchrus ciliaris (Poaceae: Paniceae

    Directory of Open Access Journals (Sweden)

    N. C. Visser

    1999-12-01

    Full Text Available Synaptic mutants are present in  Cenchrus ciliaris L This species, due to the presence of linear bivalents and occasion­al trivalents and quadrivalents, is an intermediate desynaptic species. In addition, geographical distribution and environmental factors, such as high temperatures and low humidity, could also have had an influence on the desynapsis observed.The disjunction of chromosomes during anaphase I was mostly abnormal in this desynaptic species. Precocious disjunction of chromosomes into chromatids occurred during anaphase I Due to the high incidence of this chromosome abnormality, a mutant gene,  'pc'  responsible for the disjunction of chromosomes, must be present. The absence of cytokinesis in one specimen indicates a recessive mutant gene,  'va' to be active in this species.

  13. TMEM107 recruits ciliopathy proteins to subdomains of the ciliary transition zone and causes Joubert syndrome.

    Science.gov (United States)

    Lambacher, Nils J; Bruel, Ange-Line; van Dam, Teunis J P; Szymańska, Katarzyna; Slaats, Gisela G; Kuhns, Stefanie; McManus, Gavin J; Kennedy, Julie E; Gaff, Karl; Wu, Ka Man; van der Lee, Robin; Burglen, Lydie; Doummar, Diane; Rivière, Jean-Baptiste; Faivre, Laurence; Attié-Bitach, Tania; Saunier, Sophie; Curd, Alistair; Peckham, Michelle; Giles, Rachel H; Johnson, Colin A; Huynen, Martijn A; Thauvin-Robinet, Christel; Blacque, Oliver E

    2016-01-01

    The transition zone (TZ) ciliary subcompartment is thought to control cilium composition and signalling by facilitating a protein diffusion barrier at the ciliary base. TZ defects cause ciliopathies such as Meckel-Gruber syndrome (MKS), nephronophthisis (NPHP) and Joubert syndrome (JBTS). However, the molecular composition and mechanisms underpinning TZ organization and barrier regulation are poorly understood. To uncover candidate TZ genes, we employed bioinformatics (coexpression and co-evolution) and identified TMEM107 as a TZ protein mutated in oral-facial-digital syndrome and JBTS patients. Mechanistic studies in Caenorhabditis elegans showed that TMEM-107 controls ciliary composition and functions redundantly with NPHP-4 to regulate cilium integrity, TZ docking and assembly of membrane to microtubule Y-link connectors. Furthermore, nematode TMEM-107 occupies an intermediate layer of the TZ-localized MKS module by organizing recruitment of the ciliopathy proteins MKS-1, TMEM-231 (JBTS20) and JBTS-14 (TMEM237). Finally, MKS module membrane proteins are immobile and super-resolution microscopy in worms and mammalian cells reveals periodic localizations within the TZ. This work expands the MKS module of ciliopathy-causing TZ proteins associated with diffusion barrier formation and provides insight into TZ subdomain architecture. PMID:26595381

  14. [A rare case of primary ciliary dyskinesia with heterotaxy].

    Science.gov (United States)

    Quintela, Cátia; Meireles, Cláudia; Bettencourt, Maria João; Ribeirinho, Augusto; Bentes, Teresa

    2009-01-01

    Primary ciliary dyskinesia is an autosomal recessive disease with a clinical history of upper and lowers respiratory infections, rhinosinusitis and bronquitis associated with complete or partial situs inversus. The authors present a 78 -year -old male caucasian patient with rhinosinusitis, lower respiratory tract infection and dyspnea, chronic otitis with hearing deficit and infertility followed in Gastroenterology for dyspepsia and constipation. The radiological studies revealed agenesis of right frontal sinus; bronchial wall thickening; bronchiectasis; cecum and ascending colon located on the left and small bowel occupies right side of abdomen. He had no immunodeficiency, allergies, cystic fibrosis and others. We concluded primary ciliary dyskinesia with heterotaxy. For the rarity of this case we decided to present it. PMID:19145394

  15. Predator avoidance by nauplii

    DEFF Research Database (Denmark)

    Titelman, Josefin; Kiørboe, Thomas

    2003-01-01

    upwards and also away from the flow, and are thus able to assess direction of flow. Sensitivity to hydrodynamic signals is tightly linked to the general motility pattern. Hydrodynamically conspicuous nauplii that move in a jump-sink pattern are more effective at remotely detecting predators than are...... continuous swimmers of similar size. We assessed the effects of different motility strategies in terms of detectability and volume encounter with copepod predators by means of simple hydrodynamic models. While jump-sink type nauplii may be at an advantage over swimmers in interactions with sinking and......We examined anti-predation strategies in relation to motility patterns for early and late nauplii of 6 species of copepods (Calanus helgolandicus, Centropages typicus, Eurytemora affinis, Euterpina acutifrons, Acartia tonsa and Temora longicornis). Remote detection and escape abilities were...

  16. Systemic administration of ciliary neurotrophic factor induces cachexia in rodents.

    OpenAIRE

    Henderson, J T; Seniuk, N A; Richardson, P.M.; Gauldie, J; Roder, J. C.

    1994-01-01

    Ciliary neurotrophic factor (CNTF) has previously been shown to promote the survival of several classes of neurons and glial. We report here that in addition to its effects on the nervous system, CNTF can induce potent effects in extra-neural tissues. Implantation of C6 glioma cells engineered to secrete CNTF either subcutaneously or into the peritoneal cavity of adult mice, or systemic injections of purified rat or human recombinant CNTF, resulted in a rapid syndrome of weight loss resulting...

  17. Ciliary Neurotrophic Factor Receptor Regulation of Adult Forebrain Neurogenesis

    OpenAIRE

    Lee, Nancy; Batt, Myra K.; Cronier, Brigitte A.; Jackson, Michele C.; Bruno Garza, Jennifer L; Trinh, Dennis S.; Mason, Carter O.; Spearry, Rachel P.; Bhattacharya, Shayon; Robitz, Rachel; Nakafuku, Masato; MacLennan, A. John

    2013-01-01

    Appropriately targeted manipulation of endogenous neural stem progenitor (NSP) cells may contribute to therapies for trauma, stroke, and neurodegenerative disease. A prerequisite to such therapies is a better understanding of the mechanisms regulating adult NSP cells in vivo. Indirect data suggest that endogenous ciliary neurotrophic factor (CNTF) receptor signaling may inhibit neuronal differentiation of NSP cells. We challenged subventricular zone (SVZ) cells in vivo with low concentrations...

  18. Effect of ciliary neurotrophic factor (CNTF) on motoneuron survival

    OpenAIRE

    Sendtner, Michael; Arakawa, Yoshihiro; Stöckli, Kurt A.; Kreutzberg, Georg W.; Thoenen, Hans

    2010-01-01

    We have demonstrated that the extensive degeneration of motoneurons in the rat facial nucleus after transection of the facial nerve in newborn rats can be prevented by local ciliary neurotrophic factor (CNTF) administration. CNTF differs distinctly from known neurotrophic molecules such as NGF, BDNF and NT-3 in both its molecular characteristics (CNTF is a cytosolic rather than a secretory molecule) and its broad spectrum of biological activities. CNTF is expressed selectively by Schwann cell...

  19. Meiotic chromosome behaviour in Cenchrus ciliaris

    Directory of Open Access Journals (Sweden)

    N. C. Visser

    1998-12-01

    Full Text Available A basic chromosome number of x = 9 has been confirmed for Cenchrus ciliaris L. Polyploidy is common and levels vary from tetraploid to hexaploid. Aneuploidv is reported for a single specimen, where two chromosomes of a single genome were lost. Various meiotic irregularities were observed. The highest incidence of meiotic abnormalities was observed in the pentaploid specimens. This was attributed to their uneven polyploid level All specimens varied from segmental alloploid to alloploid.

  20. Myristoylated CIL-7 regulates ciliary extracellular vesicle biogenesis.

    Science.gov (United States)

    Maguire, Julie E; Silva, Malan; Nguyen, Ken C Q; Hellen, Elizabeth; Kern, Andrew D; Hall, David H; Barr, Maureen M

    2015-08-01

    The cilium both releases and binds to extracellular vesicles (EVs). EVs may be used by cells as a form of intercellular communication and mediate a broad range of physiological and pathological processes. The mammalian polycystins (PCs) localize to cilia, as well as to urinary EVs released from renal epithelial cells. PC ciliary trafficking defects may be an underlying cause of autosomal dominant polycystic kidney disease (PKD), and ciliary-EV interactions have been proposed to play a central role in the biology of PKD. In Caenorhabditis elegans and mammals, PC1 and PC2 act in the same genetic pathway, act in a sensory capacity, localize to cilia, and are contained in secreted EVs, suggesting ancient conservation. However, the relationship between cilia and EVs and the mechanisms generating PC-containing EVs remain an enigma. In a forward genetic screen for regulators of C. elegans PKD-2 ciliary localization, we identified CIL-7, a myristoylated protein that regulates EV biogenesis. Loss of CIL-7 results in male mating behavioral defects, excessive accumulation of EVs in the lumen of the cephalic sensory organ, and failure to release PKD-2::GFP-containing EVs to the environment. Fatty acylation, such as myristoylation and palmitoylation, targets proteins to cilia and flagella. The CIL-7 myristoylation motif is essential for CIL-7 function and for targeting CIL-7 to EVs. C. elegans is a powerful model with which to study ciliary EV biogenesis in vivo and identify cis-targeting motifs such as myristoylation that are necessary for EV-cargo association and function. PMID:26041936

  1. Photosynthesis of Digitaria ciliaris during repeated soil drought and rewatering

    Institute of Scientific and Technical Information of China (English)

    YaYong Luo; XueYong Zhao; JingHui Zhang; YuLin Li; XiaoAn Zuo; DianChao Sun

    2015-01-01

    The ability of psammophyte photosynthesis to withstand and recover from severe droughts is crucial for vegetation sta-bility in semi-arid sandy lands. The responses of gas exchange and chlorophyll fluorescence of an annual grass, Digitaria ciliaris, were measured through three soil drought and rewatering cycles. Results showed that the net photosynthesis rate (Pn) decreased by 92%, 95%, and 63%at end of the three drought periods, respectively, water use efficiency (WUE) de-creased by 67%, 54%, and 48%, while the constant intercellular CO2 concentration (Ci) increased by 1.08, 0.88, and 0.45 times. During those three cycles, the trapping probability with no dark adaptation (Fv′/Fm′) decreased by 55%, 51%, and 9%, the electron transport per cross section (ET0′/CS0′) decreased by 63%, 42%, and 18%, and the dissipation per cross section (DI0′/CS0′) increased by 97%, 96%, and 21%. These results indicated that D. ciliaris was subjected to photoinhi-bition and some non-stomatal limitation of photosynthesis under drought. However, after four days of rewatering, its photosynthetic characteristics were restored to control values. This capability to recover from drought may contribute to making the plant's use of water as efficient as possible. Furthermore, the photosynthesis decreased more slowly in the subsequent drought cycles than in the first cycle, allowing D. ciliaris to enhance its future drought tolerance after drought hardening. Thus, it acclimatizes itself to repeated soil drought.

  2. The Contribution of Ciliary Neurotrophic Factor Receptors to Adult Motor Neuron Survival In Vivo Is Specific to Insult Type and Distinct From That for Embryonic Motor Neurons

    OpenAIRE

    Lee, Nancy; Rydyznski, Carolyn E.; Spearry, Rachel P.; Robitz, Rachel; MacLennan, A. John

    2013-01-01

    Exogenous ciliary neurotrophic factor (CNTF) promotes motor neuron (MN) survival following trauma and in genetic models of MN disease. Unconditional disruption of the mouse CNTF receptor α (CNTFRα) gene leads to MN loss, demonstrating a developmental role for endogenous CNTF receptor signaling. These data also suggest that CNTF receptors may promote adult MN survival and that appropriately manipulating the receptors could effectively treat adult MN disorders. This effort would greatly benefit...

  3. Mutations in DNAJB13, Encoding an HSP40 Family Member, Cause Primary Ciliary Dyskinesia and Male Infertility.

    Science.gov (United States)

    El Khouri, Elma; Thomas, Lucie; Jeanson, Ludovic; Bequignon, Emilie; Vallette, Benoit; Duquesnoy, Philippe; Montantin, Guy; Copin, Bruno; Dastot-Le Moal, Florence; Blanchon, Sylvain; Papon, Jean François; Lorès, Patrick; Yuan, Li; Collot, Nathalie; Tissier, Sylvie; Faucon, Catherine; Gacon, Gérard; Patrat, Catherine; Wolf, Jean Philippe; Dulioust, Emmanuel; Crestani, Bruno; Escudier, Estelle; Coste, André; Legendre, Marie; Touré, Aminata; Amselem, Serge

    2016-08-01

    Primary ciliary dyskinesia (PCD) is an autosomal-recessive disease due to functional or ultra-structural defects of motile cilia. Affected individuals display recurrent respiratory-tract infections; most males are infertile as a result of sperm flagellar dysfunction. The great majority of the PCD-associated genes identified so far encode either components of dynein arms (DAs), which are multiprotein-ATPase complexes essential for ciliary motility, or proteins involved in DA assembly. To identify the molecular basis of a PCD phenotype characterized by central complex (CC) defects but normal DA structure, a phenotype found in ∼15% of cases, we performed whole-exome sequencing in a male individual with PCD and unexplained CC defects. This analysis, combined with whole-genome SNP genotyping, identified a homozygous mutation in DNAJB13 (c.833T>G), a gene encoding a HSP40 co-chaperone whose ortholog in the flagellated alga Chlamydomonas localizes to the radial spokes. In vitro studies showed that this missense substitution (p.Met278Arg), which involves a highly conserved residue of several HSP40 family members, leads to protein instability and triggers proteasomal degradation, a result confirmed by the absence of endogenous DNAJB13 in cilia and sperm from this individual. Subsequent DNAJB13 analyses identified another homozygous mutation in a second family; the study of DNAJB13 transcripts obtained from airway cells showed that this mutation (c.68+1G>C) results in a splicing defect consistent with a loss-of-function mutation. Overall, this study, which establishes mutations in DNAJB13 as a cause of PCD, unveils the key role played by DNAJB13 in the proper formation and function of ciliary and flagellar axonemes in humans. PMID:27486783

  4. Computational modelling elucidates the mechanism of ciliary regulation in health and disease

    Directory of Open Access Journals (Sweden)

    Hundhausen Christian

    2011-09-01

    Full Text Available Abstract Background Ciliary dysfunction leads to a number of human pathologies, including primary ciliary dyskinesia, nephronophthisis, situs inversus pathology or infertility. The mechanism of cilia beating regulation is complex and despite extensive experimental characterization remains poorly understood. We develop a detailed systems model for calcium, membrane potential and cyclic nucleotide-dependent ciliary motility regulation. Results The model describes the intimate relationship between calcium and potassium ionic concentrations inside and outside of cilia with membrane voltage and, for the first time, describes a novel type of ciliary excitability which plays the major role in ciliary movement regulation. Our model describes a mechanism that allows ciliary excitation to be robust over a wide physiological range of extracellular ionic concentrations. The model predicts the existence of several dynamic modes of ciliary regulation, such as the generation of intraciliary Ca2+ spike with amplitude proportional to the degree of membrane depolarization, the ability to maintain stable oscillations, monostable multivibrator regimes, all of which are initiated by variability in ionic concentrations that translate into altered membrane voltage. Conclusions Computational investigation of the model offers several new insights into the underlying molecular mechanisms of ciliary pathologies. According to our analysis, the reported dynamic regulatory modes can be a physiological reaction to alterations in the extracellular environment. However, modification of the dynamic modes, as a result of genetic mutations or environmental conditions, can cause a life threatening pathology.

  5. Discinesia ciliar primária Primary ciliary dyskinesia

    Directory of Open Access Journals (Sweden)

    JOSÉ WELLINGTON ALVES DOS SANTOS

    2001-09-01

    Full Text Available Discinesia ciliar primária é uma doença autossômica recessiva caracterizada pela história de infecções repetidas do trato respiratório superior e inferior, otite média, bronquite e rinossinusite, associada a situs inversus na metade dos casos. O diagnóstico é estabelecido pela análise ciliar ultra-estrutural de espécimes respiratórios, após a exclusão inicial de outras doenças, como fibrose cística, deficiência de alfa-1-antitripsina, imunodeficiências (IgG, neutrófilos e complemento e síndrome de Young. O propósito deste artigo é revisar os achados clínicos, o diagnóstico e o manejo da discinesia ciliar primária, incluindo um fluxograma diagnóstico.Primary ciliary dyskinesia is an autosomal recessive disorder characterized by a history of recurrent upper and lower respiratory tract infections with chronic otitis media, bronchitis and rhinosinusitis, associated with situs inversus in 50% of cases. The diagnosis is established by ciliary ultrastructural analysis of respiratory specimens, after ruling out some disorders as cystic fibrosis, alpha-1 anti-trypsin deficiency, immune deficiencies (IgG, neutrophils and complement and Young's syndrome. The purpose of this paper is to review the clinical features, diagnosis and management of primary ciliary dyskinesia, including a diagnostic algorithm.

  6. Pengujian Perilaku Predator dan Anti-Predator pada Ikan Lele Dumbo (Clarias gariepinus Burchell, 1822) Transgenik F3

    OpenAIRE

    Widyawati, Putri

    2015-01-01

    African catfish (Clarias gariepinus) transgenic F3 containing Pangasius hypothalmus growth hormone (PhGH) genes can growth twice the average weight of the control population. However, before transgenic African catfish are released and utilized, their genetic impact on the natural environment must be examined. Predator avoidance is one of the major fitness traits determining potential environment risk. To determine the predator avoidance ability and growth performance of transgenic African cat...

  7. Biometry of the ciliary muscle during dynamic accommodation assessed with OCT

    Science.gov (United States)

    Ruggeri, Marco; Hernandez, Victor; de Freitas, Carolina; Manns, Fabrice; Parel, Jean-Marie

    2014-02-01

    Little is known about the structural changes of the ciliary muscle with age and how it may contribute to presbyopia. Optical coherence tomography (OCT) has been used to perform ciliary muscle biometry at different age and accommodative states with low resolution and speed. Dynamic imaging and accurate biometry of the ciliary muscle requires high-speed, high-resolution and correction of the OCT image distortions. We integrate an existing custom-made Spectral Domain OCT (SD-OCT) platform working at 840nm for biometry of the human eye with a SD-OCT system working at 1325nm that enables high-speed and high-resolution transscleral imaging of the ciliary muscle dynamically during accommodation and we developed an algorithm to provide corrected thickness measurements of the ciliary muscle.

  8. Oligodendroglioma of the ciliary body: a unique case report and the review of literature

    International Nuclear Information System (INIS)

    To date, there is no report in the international literature of an oligodendroglioma of the ciliary body, nor is there an analysis of the possible origins of this lesion. Here we report on a 52-year-old man admitted to our hospital with a ciliary body tumor revealed by clinical examination and ultrasound, computed tomography and magnetic resonance imaging studies. Following enucleation, pathological and immunohistochemical analyses were performed. Postoperative histopathological staining results included OLIGO-2(+) and GFAP(-), leading to a pathological diagnosis of oligodendroglioma of the ciliary body in the right eye (WHO grade II). Since malignant gliomas derive from transformed neural stem cells, the presence of oligodendroglioma in the ciliary body supports the hypothesis that gliomas can occur wherever neural stem cells exist. Tumors of the ciliary body derived from oligodendrocytes are difficult to diagnose; pathological analyses are essential

  9. Leopard predation and primate evolution.

    Science.gov (United States)

    Zuberbühler, Klaus; Jenny, David

    2002-12-01

    Although predation is an important driving force of natural selection its effects on primate evolution are still not well understood, mainly because little is known about the hunting behaviour of the primates' various predators. Here, we present data on the hunting behaviour of the leopard (Panthera pardus), a major primate predator in the Tai; forest of Ivory Coast and elsewhere. Radio-tracking data showed that forest leopards primarily hunt for monkeys on the ground during the day. Faecal analyses confirmed that primates accounted for a large proportion of the leopards' diet and revealed in detail the predation pressure exerted on the eight different monkey and one chimpanzee species. We related the species-specific predation rates to various morphological, behavioural and demographic traits that are usually considered adaptations to predation (body size, group size, group composition, reproductive behaviour, and use of forest strata). Leopard predation was most reliably associated with density, suggesting that leopards hunt primates according to abundance. Contrary to predictions, leopard predation rates were not negatively, but positively, related to body size, group size and the number of males per group, suggesting that predation by leopards did not drive the evolution of these traits in the predicted way. We discuss these findings in light of some recent experimental data and suggest that the principal effect of leopard predation has been on primates' cognitive evolution. PMID:12473487

  10. Predator Avoidance in Extremophile Fish

    Directory of Open Access Journals (Sweden)

    Martin Plath

    2013-02-01

    Full Text Available Extreme habitats are often characterized by reduced predation pressures, thus representing refuges for the inhabiting species. The present study was designed to investigate predator avoidance of extremophile populations of Poecilia mexicana and P. sulphuraria that either live in hydrogen sulfide-rich (sulfidic springs or cave habitats, both of which are known to have impoverished piscine predator regimes. Focal fishes that inhabited sulfidic springs showed slightly weaker avoidance reactions when presented with several naturally occurring predatory cichlids, but strongest differences to populations from non-sulfidic habitats were found in a decreased shoaling tendency with non-predatory swordtail (Xiphophorus hellerii females. When comparing avoidance reactions between P. mexicana from a sulfidic cave (Cueva del Azufre and the adjacent sulfidic surface creek (El Azufre, we found only slight differences in predator avoidance, but surface fish reacted much more strongly to the non-predatory cichlid Vieja bifasciata. Our third experiment was designed to disentangle learned from innate effects of predator recognition. We compared laboratory-reared (i.e., predator-naïve and wild-caught (i.e., predator-experienced individuals of P. mexicana from a non-sulfidic river and found no differences in their reaction towards the presented predators. Overall, our results indicate (1 that predator avoidance is still functional in extremophile Poecilia spp. and (2 that predator recognition and avoidance reactions have a strong genetic basis.

  11. Caenorhabditis elegans ciliary protein NPHP-8, the homologue of human RPGRIP1L, is required for ciliogenesis and chemosensation.

    Science.gov (United States)

    Liu, Lin; Zhang, Mingshu; Xia, Zhiping; Xu, Pingyong; Chen, Liangyi; Xu, Tao

    2011-07-01

    Nephronophthisis (NPHP) is the most frequent genetic cause of end-stage renal failure in children and young adults. NPHP8/RPGRIP1L is a novel ciliary gene that, when mutated, in addition to causing NPHP, also causes Joubert syndrome (JBTS) and Meckel syndrome (MKS). The exact function of NPHP8 and how defects in NPHP8 lead to human diseases are poorly understood. Here, we studied the Caenorhabditis elegans homolog nphp-8 (C09G5.8) and explored the possible function of NPHP-8 in ciliated sensory neurons. We determined the gene structure of nphp-8 through rapid amplification of cDNA ends (RACE) analysis and discovered an X-box motif that had been previously overlooked. Moreover, NPHP-8 co-localized with NPHP-4 at the transition zone at the base of cilia. Mutation of nphp-8 led to abnormal dye filling (Dyf) and shorter cilia lengths in a subset of ciliary neurons. In addition, chemotaxis to several volatile attractants was significantly impaired in nphp-8 mutants. Our data suggest that NPHP-8/RPGRIP1L plays an important role in cilia formation and cilia-mediated chemosensation in a cell type-specific manner. PMID:21689635

  12. OFD1, as a Ciliary Protein, Exhibits Neuroprotective Function in Photoreceptor Degeneration Models.

    Directory of Open Access Journals (Sweden)

    Juan Wang

    Full Text Available Ofd1 is a newly identified causative gene for Retinitis pigmentosa (RP, a photoreceptor degenerative disease. This study aimed to examine Ofd1 localization in retina and further to investigate its function in photoreceptor degeneration models. Ofd1 localization in rat retina was examined using immunofluorescence. N-methyl-N-nitrosourea (MNU-induced rats and Royal College of Surgeons (RCS rats were used as photoreceptor degeneration models. The expression pattern of Ofd1, other ciliary associated genes and Wnt signaling pathway genes were examined in rat models. Furthermore, pEGFP-Ofd1-CDS and pSUPER-Ofd1-shRNA were constructed to overexpress and knockdown the expression level in 661W and R28 cells. MNU was also used to induce cell death. Cilia formation was observed using immunocytochemistry (ICC. Reactive oxygen species (ROS were detected using the 2', 7'-Dichlorofluorescin diacetate (DCFH-DA assay. Apoptosis genes expression was examined using qRT-PCR, Western blotting and fluorescence-activated cell sorting (FACS. Ofd1 localized to outer segments of rat retina photoreceptors. Ofd1 and other ciliary proteins expression levels increased from the 1st and 4th postnatal weeks and decreased until the 6th week in the RCS rats, while their expression consistently decreased from the 1st and 7th day in the MNU rats. Moreover, Wnt signaling pathway proteins expression was significantly up-regulated in both rat models. Knockdown of Ofd1 expression resulted in a smaller population, shorter length of cell cilia, and lower cell viability. Ofd1 overexpression partially attenuated MNU toxic effects by reducing ROS levels and mitigating apoptosis. To the best of our knowledge, this is the first study demonstrating Ofd1 localization and its function in rat retina and in retinal degeneration rat models. Ofd1 plays a role in controlling photoreceptor cilium length and number. Importantly, it demonstrates a neuroprotective function by protecting the photoreceptor

  13. Top predators induce the evolutionary diversification of intermediate predator species.

    Science.gov (United States)

    Zu, Jian; Yuan, Bo; Du, Jianqiang

    2015-12-21

    We analyze the evolutionary branching phenomenon of intermediate predator species in a tritrophic food chain model by using adaptive dynamics theory. Specifically, we consider the adaptive diversification of an intermediate predator species that feeds on a prey species and is fed upon by a top predator species. We assume that the intermediate predator׳s ability to forage on the prey can adaptively improve, but this comes at the cost of decreased defense ability against the top predator. First, we identify the general properties of trade-off relationships that lead to a continuously stable strategy or to evolutionary branching in the intermediate predator species. We find that if there is an accelerating cost near the singular strategy, then that strategy is continuously stable. In contrast, if there is a mildly decelerating cost near the singular strategy, then that strategy may be an evolutionary branching point. Second, we find that after branching has occurred, depending on the specific shape and strength of the trade-off relationship, the intermediate predator species may reach an evolutionarily stable dimorphism or one of the two resultant predator lineages goes extinct. PMID:26431773

  14. Automatic analysis of ciliary beat frequency using optical flow

    Science.gov (United States)

    Figl, Michael; Lechner, Manuel; Werther, Tobias; Horak, Fritz; Hummel, Johann; Birkfellner, Wolfgang

    2012-02-01

    Ciliary beat frequency (CBF) can be a useful parameter for diagnosis of several diseases, as e.g. primary ciliary dyskinesia. (PCD). CBF computation is usually done using manual evaluation of high speed video sequences, a tedious, observer dependent, and not very accurate procedure. We used the OpenCV's pyramidal implementation of the Lukas-Kanade algorithm for optical flow computation and applied this to certain objects to follow the movements. The objects were chosen by their contrast applying the corner detection by Shi and Tomasi. Discrimination between background/noise and cilia by a frequency histogram allowed to compute the CBF. Frequency analysis was done using the Fourier transform in matlab. The correct number of Fourier summands was found by the slope in an approximation curve. The method showed to be usable to distinguish between healthy and diseased samples. However there remain difficulties in automatically identifying the cilia, and also in finding enough high contrast cilia in the image. Furthermore the some of the higher contrast cilia are lost (and sometimes found) by the method, an easy way to distinguish the correct sub-path of a point's path have yet to be found in the case where the slope methods doesn't work.

  15. Expression of nitric oxide synthase and guanylate cyclase in the human ciliary body and trabecular meshwork

    Institute of Scientific and Technical Information of China (English)

    WU Ren-yi; MA Ning

    2012-01-01

    Background The role played by the nitric oxide (NO) signaling pathway in the aqueous humor dynamics is still unclear.This study was designed to investigate the expression and distribution of NO synthase (NOS) isoforms and guanylate cyclase (GC) in human ciliary body,trabecular meshwork and the Schlemm's canal.Methods Twelve eyes after corneal transplantation were used.Expression of three NOS isoforms (i.e.neuronal NOS (nNOS),inducible NOS (iNOS) and endothelial NOS (eNOS)) and GC were assessed in 10 eyes by immunohistochemical staining using monoclonal or polyclonal antibody of NOS and GC.Ciliary bodies were dissected free and the total proteins were extracted.Western blotting was performed to confirm the protein expression of 3 NOS isoforms and GC.Results Expression of 3 NOS isoforms and GC were observed in the ciliary epithelium,ciliary muscle,trabecular meshwork and the endothelium of the Schlemm's canal.Immunoreactivity of nNOS was detected mainly along the apical cytoplasmic junction of the non-pigmented epithelium (NPE) and pigmented epithelial (PE) cells.Protein expressions of 3 NOS isoforms and GC were confirmed in isolated human ciliary body by Western blotting.Conclusions The expression of NOS isoforms and GC in human ciliary body suggest the possible involvement of NO and cyclic guanosine monophosphate (cyclic GMP,cGMP) signaling pathway in the ciliary body,and may play a role in both processes of aqueous humor formation and drainage.

  16. Human ciliary neurotrophic factor: Localization to the proximal region of the long arm of chromosome 11 and association with CA/GT dinucleotide repeat

    Energy Technology Data Exchange (ETDEWEB)

    Lev, A.A.; Rosen, D.R.; Kos, C.; Brown, R.H. Jr.; Clifford, E.; Landes, G.; Hauser, S.L.

    1993-05-01

    Ciliary neurotrophic factor (CNTF) promotes survival and differentiation of several types of sensory, motor, sympathetic, and parasympathetic neurons. The authors have used the polymerase chain reaction to amplify, clone, and partially sequence CNTF cDNA from human muscle. Using a rodent-human mapping panel and fluorescence in situ hybridization, they have localized a single copy of the gene for human CNTF to the proximal long arm of chromosome 11. They have also identified a polymorphic tandem CA/GT dinucleotide repeat associated with the human CNTF gene. 14 refs., 1 fig.

  17. Zebrafish Ciliopathy Screen Plus Human Mutational Analysis Identifies C21orf59 and CCDC65 Defects as Causing Primary Ciliary Dyskinesia

    OpenAIRE

    Austin-Tse, Christina; Halbritter, Jan; Zariwala, Maimoona A.; Gilberti, Renée M.; Gee, Heon Yung; Hellman, Nathan; Pathak, Narendra; Liu, Yan; Panizzi, Jennifer R.; Patel-King, Ramila S.; Tritschler, Douglas; Bower, Raqual; O’Toole, Eileen; Porath, Jonathan D.; Hurd, Toby W.

    2013-01-01

    Primary ciliary dyskinesia (PCD) is caused when defects of motile cilia lead to chronic airway infections, male infertility, and situs abnormalities. Multiple causative PCD mutations account for only 65% of cases, suggesting that many genes essential for cilia function remain to be discovered. By using zebrafish morpholino knockdown of PCD candidate genes as an in vivo screening platform, we identified c21orf59, ccdc65, and c15orf26 as critical for cilia motility. c21orf59 and c15orf26 knockd...

  18. Decoys in Predation and Parasitism

    NARCIS (Netherlands)

    Wilkinson, Michael H.F.

    2003-01-01

    Predator-prey or host-parasite dynamics can be altered by the presence of other species through several mechanisms. One such mechanism is the ‘‘decoy effect,’’ which itself can take a variety of forms. In its simplest form, the third species, which is inedible to the predator, nonetheless interferes

  19. Intraocular electro-optic lens with ciliary muscle controlled accommodation.

    Science.gov (United States)

    Doornaert, Dries; Glorieux, Christ; De Gersem, Herbert; Puers, Robert; Spileers, Werner; Blanckaert, Johan

    2013-01-01

    In this paper a concept is proposed of an intraocular lens implant with electro-optic accommodation of a variable-focus hybrid liquid-crystal-based lens. The dioptric strength of the lens is electronically controlled by a signal that is derived from the change of inductance of a sensing coil due to a marker implanted in the nearby contracting or decontracting ciliary muscle. Analytical, numerical and experimental results are reported on the dependency of the frequency of a Colpitts oscillator circuit on the location of a nearby conductive marker. A concept is also reported on the use as an electro-optic lens of a device based on a liquid crystal in planar alignment, which is held between a flat and a curved window coated with optically transparent and electrically conductive layers. PMID:24110406

  20. Genotypic Variation for Salinity Tolerance in Cenchrus ciliaris L.

    Science.gov (United States)

    Al-Dakheel, Abdullah J.; Hussain, M. Iftikhar

    2016-01-01

    Scarcity of irrigation water and increasing soil salinization has threatened the sustainability of forage production in arid and semi-arid region around the globe. Introduction of salt-tolerant perennial species is a promising alternative to overcome forage deficit to meet future livestock needs in salt-affected areas. This study presents the results of a salinity tolerance screening trial which was carried out in plastic pots buried in the open field for 160 buffelgrass (Cenchrus ciliaris L.) accessions for three consecutive years (2003–2005). The plastic pots were filled with sand, organic, and peat moss mix and were irrigated with four different quality water (EC 0, 10, 15, and 20 dS m−1). The results indicate that the average annual dry weights (DW) were in the range from 122.5 to 148.9 g/pot in control; 96.4–133.8 g/pot at 10 dS m−1; 65.6–80.4 g/pot at 15 dS m−1, and 55.4–65.6 g/pot at 20 dS m−1. The highest DW (148.9 g/pot) was found with accession 49 and the lowest with accession 23. Principle component analysis shows that PC-1 contributed 81.8% of the total variability, while PC-2 depicted 11.7% of the total variation among C. ciliaris accessions for DW. Hierarchical cluster analysis revealed that a number of accessions collected from diverse regions could be grouped into a single cluster. Accessions 3, 133, 159, 30, 23, 142, 141, 95, 49, 129, 124, and 127 were stable, salt tolerant, and produced good dry biomass yield. These accessions demonstrate sufficient salinity tolerance potential for promotion in marginal lands to enhance farm productivity and reduce rural poverty. PMID:27516762

  1. Genotypic Variation for Salinity Tolerance in Cenchrus ciliaris L.

    Science.gov (United States)

    Al-Dakheel, Abdullah J; Hussain, M Iftikhar

    2016-01-01

    Scarcity of irrigation water and increasing soil salinization has threatened the sustainability of forage production in arid and semi-arid region around the globe. Introduction of salt-tolerant perennial species is a promising alternative to overcome forage deficit to meet future livestock needs in salt-affected areas. This study presents the results of a salinity tolerance screening trial which was carried out in plastic pots buried in the open field for 160 buffelgrass (Cenchrus ciliaris L.) accessions for three consecutive years (2003-2005). The plastic pots were filled with sand, organic, and peat moss mix and were irrigated with four different quality water (EC 0, 10, 15, and 20 dS m(-1)). The results indicate that the average annual dry weights (DW) were in the range from 122.5 to 148.9 g/pot in control; 96.4-133.8 g/pot at 10 dS m(-1); 65.6-80.4 g/pot at 15 dS m(-1), and 55.4-65.6 g/pot at 20 dS m(-1). The highest DW (148.9 g/pot) was found with accession 49 and the lowest with accession 23. Principle component analysis shows that PC-1 contributed 81.8% of the total variability, while PC-2 depicted 11.7% of the total variation among C. ciliaris accessions for DW. Hierarchical cluster analysis revealed that a number of accessions collected from diverse regions could be grouped into a single cluster. Accessions 3, 133, 159, 30, 23, 142, 141, 95, 49, 129, 124, and 127 were stable, salt tolerant, and produced good dry biomass yield. These accessions demonstrate sufficient salinity tolerance potential for promotion in marginal lands to enhance farm productivity and reduce rural poverty. PMID:27516762

  2. Stability of an intraguild predation system with mutual predation

    Science.gov (United States)

    Wang, Yuanshi; DeAngelis, Donald L.

    2016-04-01

    We examine intraguild predation (IGP), in which species both compete for resources or space and prey on each other. The IGP system is modeled here by a lattice gas model of the mean-field theory. First, we consider the IGP system of one species in which individuals of the same species cannibalize each other. The dynamical behavior of the model demonstrates a mechanism by which the intraspecific predation promotes persistence of the species. Then we consider the IGP system of two species with mutual predation. Global dynamics of the model exhibit basic properties of IGP: (i) When both species' efficiencies in converting the consumptions into fitness are large, the outcome of their interaction is mutualistic in form and the IGP promotes persistence of both species. (ii) When one species' efficiency is large but the other's is small, the interaction outcomes become parasitic in nature, in which an obligate species can survive through the mutual predation with a facultative one. (iii) When both species' efficiencies are small, the interaction outcomes are competitive in nature and the IGP leads to extinction of one of the species. A novel result of this work is that varying one parameter or population density of the species can lead to transition of interaction outcomes between mutualism, parasitism and competition. On the other hand, dynamics of the models demonstrate that over-predation or under-predation will result in extinction of one/both species, while intermediate predation is favorable under certain parameter ranges.

  3. Aerobic fitness in children and young adults with primary ciliary dyskinesia

    DEFF Research Database (Denmark)

    Madsen, Astrid Hellerup; Green, Kent; Buchvald, Frederik;

    2013-01-01

    BACKGROUND: Although aerobic fitness is regarded as an overall prognostic measure of morbidity and mortality, its evaluation in the chronic progressive sinopulmonary disease primary ciliary dyskinesia (PCD) has been infrequently and inconsistently reported. Here we assessed peak oxygen uptake (VO...

  4. Adenoma of nonpigmented epithelium in ciliary body:literature review and case report

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Adenomas of the nonpigmented ciliary epithelium (NPCE) are often clinically indistinguishable from amelanotic malignant melanomas of the ciliary body or metastatic carcinomas. This paper reports a case study of a distinctive variant of adenoma of the NPCE, which clinically appears as epiretinal membrane in the macular region. Histopathologic studies have revealed this is an adenoma of the NPCE. Identification of this clinic feature is important because it will miss the diagnosis of the adenoma of the NPCE. In this case study, B-scan ultrasonography as well as computerized tomography (CT) has been used to provide help in diagnosing the ciliary body tumor. Because of their anterior location in the ciliary body, partial lamellar sclerouvectomy is an effective method of treatment.

  5. Simultaneous sinus and lung infections in patients with primary ciliary dyskinesia

    DEFF Research Database (Denmark)

    Alanin, Mikkel Christian; Johansen, Helle Krogh; Aanaes, Kasper;

    2015-01-01

    Conclusion: The sinuses should be considered as a bacterial reservoir and a target for surgery and antibiotic treatment in patients with primary ciliary dyskinesia (PCD). The observed decrease in serum precipitating antibodies (precipitins) against Pseudomonas aeruginosa may indicate a beneficial...

  6. Ciliary neurotrophic factor prevents retrograde neuronal death in the adult central nervous system.

    OpenAIRE

    Clatterbuck, R E; Price, D L; Koliatsos, V E

    1993-01-01

    The neurocytokine ciliary neurotrophic factor (CNTF) was described originally as an activity that supports the survival of neurons of the chicken ciliary ganglia in vitro. The widespread expression of CNTF and its principal binding protein, CNTF receptor alpha, in the central and peripheral nervous systems suggests a broader trophic role for this peptide. In the present study, we report that CNTF prevents axotomy-induced cell death of neurons in the anteroventral and anterodorsal thalamic nuc...

  7. Primary ciliary dyskinesia: evaluation using cilia beat frequency assessment via spectral analysis of digital microscopy images

    OpenAIRE

    Olm, Mary A. K.; Kögler, João E.; Macchione, Mariangela; Shoemark, Amelia; Saldiva, Paulo H N; Rodrigues, Joaquim C.

    2011-01-01

    Ciliary beat frequency (CBF) measurements provide valuable information for diagnosing of primary ciliary dyskinesia (PCD). We developed a system for measuring CBF, used it in association with electron microscopy to diagnose PCD, and then analyzed characteristics of PCD patients.1 The CBF measurement system was based on power spectra measured through digital imaging. Twenty-four patients suspected of having PCD (age 1–19 yr) were selected from a group of 75 children and adolescents with pneumo...

  8. Transition fibre protein FBF1 is required for the ciliary entry of assembled intraflagellar transport complexes

    OpenAIRE

    WEI, QING; Xu, Qingwen; Zhang, Yuxia; Li, Yujie; Zhang, Qing; Hu, Zeng; Harris, Peter C.; Torres, Vicente E.; Ling, Kun; Hu, Jinghua

    2013-01-01

    Sensory organelle cilia play critical roles in mammalian embryonic development and tissue homeostasis. Intraflagellar transport (IFT) machinery is required for the assembly and maintenance of cilia. Yet how this large complex passes through the size-dependent barrier at the ciliary base remains enigmatic. Here we report that FBF1, a highly conserved transition fibre protein, is required for the ciliary import of assembled IFT particles at the cilia base. We cloned dyf-19, the C. elegans homol...

  9. Roles of paroxetine and corticosterone on adult mammalian ciliary body cell proliferation

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; LAU Benson WM; YAU Suk-yu; LI Suk-yee; LEUNG Nelson; WANG Ning-li; TANG Siu-wa; LEE Tatia MC; SO Kwok-fai

    2010-01-01

    Background The neurogenesis in retina of adult mammals is generally abolished, and this renders the retina lack of regenerative capacity.Despite this, there is a small population of nestin-positive cells in the ciliary epithelium which retains neurogenic potential.The present study aimed at investigating the effect of two drugs, corticosterone and paroxetine, on the cell proliferation of the ciliary body.Methods Adult Sprague-Dawley rats were given vehicle, corticosterone, paroxetine, or both corticosterone and paroxetine treatment for 14 days.Cell proliferation in the ciliary body was quantified using 5-bromo-2-deoxyuridine (BrdU) immunohistochemistry.Co-labelling of BrdU and stem cell marker was used to phenotype the BrdU immunoreactive cells.Results Corticosterone treatment suppressed while paroxetine treatment increased the cell proliferation of the ciliary body.Co-labelling with cell markers revealed that the BrdU positive cells also showed nestin expression but not glial fibrillary acidic protein (GFAP).Conclusions The results illustrate that proliferation of retinal progenitor cells situated in ciliary body are subjected to regulation by selective serotonin reuptake inhibitors (SSRI) and corticosteroid, which is similar to our previous findings in neurogenic regions in central nervous system (CNS).Paroxetine treatment could reverse the suppressive effect of corticosterone on ciliary body cell proliferation.This provides information for future investigation of retinal stem cell biology and potential treatment of retinal degenerative diseases.

  10. Predator control problems in Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One of the important wildlife management activities in Alaska is that of predator control. This simple statement requires some explanation. In the course of these...

  11. Annual predator management report 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Seedskadee NWR initiated its eighth consecutive year of predator management in June of 1995. The purpose of this management is to selectively remove waterfowl nest...

  12. Reg-2, A Downstream Signaling Protein in the Ciliary Neurotrophic Factor Survival Pathway, Alleviates Experimental Autoimmune Encephalomyelitis.

    Science.gov (United States)

    Jiang, Hong; Tian, Ke-Wei; Zhang, Fan; Wang, Beibei; Han, Shu

    2016-01-01

    Ciliary neurotrophic factor (CNTF), originally described as a neurocytokine that could support the survival of neurons, has been recently found to alleviate demyelination, prevent axon loss, and improve functional recovery in a rat model of acute experimental autoimmune encephalomyelitis (EAE). However, poor penetration into the brain parenchyma and unfavorable side effects limit the utility of CNTF. Here, we evaluated the therapeutic potential of a protein downstream of CNTF, regeneration gene protein 2 (Reg-2). Using multiple morphological, molecular biology, and electrophysiological methods to assess neuroinflammation, axonal loss, demyelination, and functional impairment, we observed that Reg-2 and CNTF exert similar effects in the acute phase of EAE. Both treatments attenuated axonal loss and demyelination, improved neuronal survival, and produced functional improvement. With a smaller molecular weight and improved penetration into the brain parenchyma, Reg-2 may be a useful substitute for CNTF therapy in EAE and multiple sclerosis (MS). PMID:27242448

  13. Megalin–deficiency causes high myopia, retinal pigment epithelium-macromelanosomes and abnormal development of the ciliary body in mice

    DEFF Research Database (Denmark)

    Storm, Tina; Heegaard, Steffen; Christensen, Erik I; Nielsen, Rikke

    2014-01-01

    In man, mutations of the megalin-encoding gene causes the rare Donnai-Barrow/Facio-Oculo-Acoustico-Renal Syndrome, which is partially characterized by high-grade myopia. Previous studies of renal megalin function have established that megalin is crucial for conservation of renal filtered nutrients...... megalin localizes to vesicular structures in the RPE and NPCBE cells. Histological investigations of ocular mouse tissue also identified a severe myopia phenotype as well as enlarged RPE melanosomes and abnormal ciliary body development in the megalin-deficient mice. In conclusion, the complex ocular...... phenotype observed in the megalin-deficient mice suggests that megalin-mediated developmental abnormalities may contribute to the high myopia phenotype observed in the Donnai-Barrow Syndrome patients and, thus, that megalin harbors important roles in ocular development and physiology. Finally, our data show...

  14. Reg-2, A Downstream Signaling Protein in the Ciliary Neurotrophic Factor Survival Pathway, Alleviates Experimental Autoimmune Encephalomyelitis

    Science.gov (United States)

    Jiang, Hong; Tian, Ke-Wei; Zhang, Fan; Wang, Beibei; Han, Shu

    2016-01-01

    Ciliary neurotrophic factor (CNTF), originally described as a neurocytokine that could support the survival of neurons, has been recently found to alleviate demyelination, prevent axon loss, and improve functional recovery in a rat model of acute experimental autoimmune encephalomyelitis (EAE). However, poor penetration into the brain parenchyma and unfavorable side effects limit the utility of CNTF. Here, we evaluated the therapeutic potential of a protein downstream of CNTF, regeneration gene protein 2 (Reg-2). Using multiple morphological, molecular biology, and electrophysiological methods to assess neuroinflammation, axonal loss, demyelination, and functional impairment, we observed that Reg-2 and CNTF exert similar effects in the acute phase of EAE. Both treatments attenuated axonal loss and demyelination, improved neuronal survival, and produced functional improvement. With a smaller molecular weight and improved penetration into the brain parenchyma, Reg-2 may be a useful substitute for CNTF therapy in EAE and multiple sclerosis (MS). PMID:27242448

  15. Reduction of ciliary beat frequency in vitro by sputum from patients with bronchiectasis: a serine proteinase effect.

    OpenAIRE

    Smallman, L A; Hill, S. L.; Stockley, R A

    1984-01-01

    We have examined the effect of adding elastase positive sputum from six patients with purulent bronchiectasis on the ciliary beat frequency of nasal epithelium from normal subjects. Control studies of cilia suspended in tissue culture medium showed little change in ciliary beat frequency over six hours. Cilia incubated in elastase positive secretions, however, showed a considerable decrease in ciliary beat frequency over the period, falling from a mean of 13 X 40 beats/second to 6 X 78 beats/...

  16. Loss-of-Function GAS8 Mutations Cause Primary Ciliary Dyskinesia and Disrupt the Nexin-Dynein Regulatory Complex

    OpenAIRE

    Olbrich, Heike; Cremers, Carolin; Loges, Niki T.; Werner, Claudius; Nielsen, Kim G.; Marthin, June K.; Philipsen, Maria; Wallmeier, Julia; Pennekamp, Petra; Menchen, Tabea; Edelbusch, Christine; Dougherty, Gerard W.; Schwartz, Oliver; Thiele, Holger; Altmüller, Janine

    2015-01-01

    Multiciliated epithelial cells protect the upper and lower airways from chronic bacterial infections by moving mucus and debris outward. Congenital disorders of ciliary beating, referred to as primary ciliary dyskinesia (PCD), are characterized by deficient mucociliary clearance and severe, recurrent respiratory infections. Numerous genetic defects, most of which can be detected by transmission electron microscopy (TEM), are so far known to cause different abnormalities of the ciliary axoneme...

  17. Force-inhibiting effect of Ser/Thr protein phosphatase 2A inhibitors on bovine ciliary muscle.

    OpenAIRE

    石田, 美織

    2015-01-01

    Ciliary muscle is a smooth muscle characterized by a rapid response to muscarinic receptor stimulation and sustained contraction. Although it is evident that these contractions are Ca(2+)-dependent, detailed molecular mechanisms are still unknown. In order to elucidate the role of Ser/Thr protein phosphatase 2A (PP2A) in ciliary muscle contraction, we examined the effects of okadaic acid and other PP2A inhibitors on contractions induced by carbachol (CCh) and ionomycin in bovine ciliary muscl...

  18. Ciliary abnormalities in senescent human fibroblasts impair proliferative capacity.

    Science.gov (United States)

    Breslin, Loretta; Prosser, Suzanna L; Cuffe, Sandra; Morrison, Ciaran G

    2014-01-01

    Somatic cells senesce in culture after a finite number of divisions indefinitely arresting their proliferation. DNA damage and senescence increase the cellular number of centrosomes, the 2 microtubule organizing centers that ensure bipolar mitotic spindles. Centrosomes also provide the basal body from which primary cilia extend to sense and transduce various extracellular signals, notably Hedgehog. Primary cilium formation is facilitated by cellular quiescence a temporary cell cycle exit, but the impact of senescence on cilia is unknown. We found that senescent human fibroblasts have increased frequency and length of primary cilia. Levels of the negative ciliary regulator CP110 were reduced in senescent cells, as were levels of key elements of the Hedgehog pathway. Hedgehog inhibition reduced proliferation in young cells with increased cilium length accompanying cell cycle arrest suggesting a regulatory function for Hedgehog in primary ciliation. Depletion of CP110 in young cell populations increased ciliation frequencies and reduced cell proliferation. These data suggest that primary cilia are potentially novel determinants of the reduced cellular proliferation that initiates senescence. PMID:25486364

  19. Ciliary abnormalities in senescent human fibroblasts impair proliferative capacity

    Science.gov (United States)

    Breslin, Loretta; Prosser, Suzanna L; Cuffe, Sandra; Morrison, Ciaran G

    2014-01-01

    Somatic cells senesce in culture after a finite number of divisions indefinitely arresting their proliferation. DNA damage and senescence increase the cellular number of centrosomes, the 2 microtubule organizing centers that ensure bipolar mitotic spindles. Centrosomes also provide the basal body from which primary cilia extend to sense and transduce various extracellular signals, notably Hedgehog. Primary cilium formation is facilitated by cellular quiescence a temporary cell cycle exit, but the impact of senescence on cilia is unknown. We found that senescent human fibroblasts have increased frequency and length of primary cilia. Levels of the negative ciliary regulator CP110 were reduced in senescent cells, as were levels of key elements of the Hedgehog pathway. Hedgehog inhibition reduced proliferation in young cells with increased cilium length accompanying cell cycle arrest suggesting a regulatory function for Hedgehog in primary ciliation. Depletion of CP110 in young cell populations increased ciliation frequencies and reduced cell proliferation. These data suggest that primary cilia are potentially novel determinants of the reduced cellular proliferation that initiates senescence. PMID:25486364

  20. PICADAR: a diagnostic predictive tool for primary ciliary dyskinesia

    Science.gov (United States)

    Behan, Laura; Dimitrov, Borislav D.; Kuehni, Claudia E.; Hogg, Claire; Carroll, Mary; Evans, Hazel J.; Goutaki, Myrofora; Harris, Amanda; Packham, Samantha; Walker, Woolf T.

    2016-01-01

    Symptoms of primary ciliary dyskinesia (PCD) are nonspecific and guidance on whom to refer for testing is limited. Diagnostic tests for PCD are highly specialised, requiring expensive equipment and experienced PCD scientists. This study aims to develop a practical clinical diagnostic tool to identify patients requiring testing. Patients consecutively referred for testing were studied. Information readily obtained from patient history was correlated with diagnostic outcome. Using logistic regression, the predictive performance of the best model was tested by receiver operating characteristic curve analyses. The model was simplified into a practical tool (PICADAR) and externally validated in a second diagnostic centre. Of 641 referrals with a definitive diagnostic outcome, 75 (12%) were positive. PICADAR applies to patients with persistent wet cough and has seven predictive parameters: full-term gestation, neonatal chest symptoms, neonatal intensive care admittance, chronic rhinitis, ear symptoms, situs inversus and congenital cardiac defect. Sensitivity and specificity of the tool were 0.90 and 0.75 for a cut-off score of 5 points. Area under the curve for the internally and externally validated tool was 0.91 and 0.87, respectively. PICADAR represents a simple diagnostic clinical prediction rule with good accuracy and validity, ready for testing in respiratory centres referring to PCD centres. PMID:26917608

  1. Genetics, diagnosis, and future treatment strategies for primary ciliary dyskinesia

    Science.gov (United States)

    Daniels, M. Leigh Anne; Noone, Peadar G.

    2015-01-01

    Introduction Primary ciliary dyskinesia (PCD) is a genetically heterogeneous recessive disorder resulting in chronic oto-sino-pulmonary disease. While PCD is estimated to occur in 1 in 20,000 individuals, fewer than 1,000 patients in the US have a well-established diagnosis. Areas Covered We provide an overview of the clinical manifestations of PCD, describe the evolution of diagnostic methods, and critique the literature on management of PCD. Expert Opinion Although interest in clinical studies in non-CF bronchiectasis has increased in recent years, some of whom enroll patients with PCD, the literature regarding therapy for PCD as a distinct entity is lacking, as the numbers are small, and there have been no sub-analyses published. However, with improved screening and diagnostic methods, the development of clinical and research consortiums, and actively enrolling registries of PCD patients, the environment is conducive to perform longitudinal studies of disease course and therapeutic studies to alter that course. PMID:26998415

  2. Can prey exhibit threat-sensitive generalization of predator recognition? Extending the Predator Recognition Continuum Hypothesis

    OpenAIRE

    Ferrari, Maud C. O.; Messier, François; Chivers, Douglas P.

    2008-01-01

    Despite the importance of predator recognition in mediating predator–prey interactions, we know little about the specific characteristics that prey use to distinguish predators from non-predators. Recent experiments indicate that some prey who do not innately recognize specific predators as threats have the ability to display antipredator responses upon their first encounter with those predators if they are similar to predators that the prey has recently learned to recognize. The purpose of o...

  3. The relationship between ciliary neurotrophic factor (CNTF genotype and motor unit physiology: preliminary studies

    Directory of Open Access Journals (Sweden)

    Ferrell Robert

    2005-09-01

    Full Text Available Abstract Background Ciliary neurotrophic factor (CNTF is important for neuronal and muscle development, and genetic variation in the CNTF gene has been associated with muscle strength. The effect of CNTF on nerve development suggests that CNTF genotype may be associated with force production via its influence on motor unit size and firing patterns. The purpose of this study is to examine whether CNTF genotype differentially affects motor unit activation in the vastus medialis with increasing isometric force during knee extension. Results Sixty-nine healthy subjects were genotyped for the presence of the G and A (null alleles in the CNTF gene (n = 57 G/G, 12 G/A. They were tested using a dynamometer during submaximal isometric knee extension contractions that were from 10–50% of their maximal strength. During the contractions, the vastus medialis was studied using surface and intramuscular electromyography with spiked triggered averaging to assess surface-detected motor unit potential (SMUP area and mean firing rates (mFR from identified motor units. CNTF genotyping was performed using standard PCR techniques from DNA obtained from leucocytes of whole blood samples. The CNTF G/A genotype was associated with smaller SMUP area motor units and lower mFR at higher force levels, and fewer but larger units at lower force levels than G/G homozygotes. The two groups used motor units with different size and activation characteristics with increasing force generation. While G/G subjects tended to utilize larger motor units with increasing force, G/A subjects showed relatively less increase in size by using relatively larger units at lower force levels. At higher force levels, G/A subjects were able to generate more force per motor unit size suggesting more efficient motor unit function with increasing muscle force. Conclusion Differential motor unit responses were observed between CNTF genotypes at force levels utilized in daily activities.

  4. Active transport and diffusion barriers restrict Joubert Syndrome-associated ARL13B/ARL-13 to an Inv-like ciliary membrane subdomain.

    Directory of Open Access Journals (Sweden)

    Sebiha Cevik

    Full Text Available Cilia are microtubule-based cell appendages, serving motility, chemo-/mechano-/photo- sensation, and developmental signaling functions. Cilia are comprised of distinct structural and functional subregions including the basal body, transition zone (TZ and inversin (Inv compartments, and defects in this organelle are associated with an expanding spectrum of inherited disorders including Bardet-Biedl syndrome (BBS, Meckel-Gruber Syndrome (MKS, Joubert Syndrome (JS and Nephronophthisis (NPHP. Despite major advances in understanding ciliary trafficking pathways such as intraflagellar transport (IFT, how proteins are transported to subciliary membranes remains poorly understood. Using Caenorhabditis elegans and mammalian cells, we investigated the transport mechanisms underlying compartmentalization of JS-associated ARL13B/ARL-13, which we previously found is restricted at proximal ciliary membranes. We now show evolutionary conservation of ARL13B/ARL-13 localisation to an Inv-like subciliary membrane compartment, excluding the TZ, in many C. elegans ciliated neurons and in a subset of mammalian ciliary subtypes. Compartmentalisation of C. elegans ARL-13 requires a C-terminal RVVP motif and membrane anchoring to prevent distal cilium and nuclear targeting, respectively. Quantitative imaging in more than 20 mutants revealed differential contributions for IFT and ciliopathy modules in defining the ARL-13 compartment; IFT-A/B, IFT-dynein and BBS genes prevent ARL-13 accumulation at periciliary membranes, whereas MKS/NPHP modules additionally inhibit ARL-13 association with TZ membranes. Furthermore, in vivo FRAP analyses revealed distinct roles for IFT and MKS/NPHP genes in regulating a TZ barrier to ARL-13 diffusion, and intraciliary ARL-13 diffusion. Finally, C. elegans ARL-13 undergoes IFT-like motility and quantitative protein complex analysis of human ARL13B identified functional associations with IFT-B complexes, mapped to IFT46 and IFT74

  5. Fiber optic laser light scattering measurement of ciliary function of the fallopian tube

    Science.gov (United States)

    Halbert, Sheridan A.; Lim, Kap; Lee, Wylie I.

    1990-07-01

    A fiber-optic laser light-scattering system (FLS) for measuring ciliary function was evaluated by means of three sets of in vitro experiments. First, FLS performance was compared to that of a previously proven benchtop laser system (BLS). Using tissue excised from rabbit fallopian tubes, ciliary beat frequency (CBF) of each sample was measured with FLS and BLS. Paired CBF measurements showed excellent correlation between the two systems (r =0.93). Second, the FLS was used to evaluate the dependency of CBF on temperature (T) by using tissue sampies of rabbit oviductal fimbna. Regression analysis of CBF vs T showed a linear relationship over the range of 18-37°C for both individual samples (r =0.98) and pooled data from all experiments (r = 0.84). Fmally, the relalionship between CBF and ciliary ovum transport rate (TR) was tested by using T to modulate CBF of rabbit fimbria, in vitro. The relationship was linear over the range of CBF from 10 to 30 Hz (r2 = 0.83). At 37°C, CBF = 31+/-1 Hz, and TR = O.12+/-.02 mm/sec. equal to ovum transport rate in situ. The FLS is a valuable tool for characterizing ciliary activity and thus ovum transport function. Owing to the fact that ciliary dyskinesia resulting from disease of the fallopian tube is associated with infeitility, the FLS may be useful to acquire data important to the clinical evaluation of fallopian tube function and female infertility.

  6. Beyond the mucus escalator: Complex ciliary hydrodynamics in disease and function

    Science.gov (United States)

    Nawroth, Janna; Guo, Hanliang; John, Dabiri; Kanso, Eva; McFall-Ngai, Margaret

    2015-11-01

    Cilia are microscopic, hair-like structures lining external and internal body surfaces where they interact with fluids. The main function of motile cilia is often described as that of a ``mucus escalator'', i.e., a homogeneous ciliary carpet moving along layer of mucus along the surface to transport food, germ cells, debris, or pathogens. Accordingly, the performance of ciliary systems is usually measured in terms of a single metric, transport velocity, or its presumed proxy, ciliary beat frequency. We challenge this simple view through the observation that both healthy and diseased biological systems exhibit a variety of cilia morphologies, beat patterns, and arrangements, resulting in complex flow patterns and transport phenomena that cannot be reduced to a single parameter. Here we present two case studies. In one system, the ciliated surface creates two distinct flow regimes for first trapping and then sheltering potential symbiont bacteria for further biochemical screening. In the other system, chronic disease induces a misalignment of ciliary beat, leading to a pathological transition from uniform mucus transport to a pattern of stagnation and circulation. These studies suggest that (a), we need to develop a wider range of metrics for describing ciliary transport in biological and clinical contexts, and (b), engineered ciliated systems exploiting a variety of design parameters could provide novel ways of manipulating fluids at the microscale.

  7. Arf4 is required for Mammalian development but dispensable for ciliary assembly.

    Directory of Open Access Journals (Sweden)

    John A Follit

    2014-02-01

    Full Text Available The primary cilium is a sensory organelle, defects in which cause a wide range of human diseases including retinal degeneration, polycystic kidney disease and birth defects. The sensory functions of cilia require specific receptors to be targeted to the ciliary subdomain of the plasma membrane. Arf4 has been proposed to sort cargo destined for the cilium at the Golgi complex and deemed a key regulator of ciliary protein trafficking. In this work, we show that Arf4 binds to the ciliary targeting sequence (CTS of fibrocystin. Knockdown of Arf4 indicates that it is not absolutely required for trafficking of the fibrocystin CTS to cilia as steady-state CTS levels are unaffected. However, we did observe a delay in delivery of newly synthesized CTS from the Golgi complex to the cilium when Arf4 was reduced. Arf4 mutant mice are embryonic lethal and die at mid-gestation shortly after node formation. Nodal cilia appeared normal and functioned properly to break left-right symmetry in Arf4 mutant embryos. At this stage of development Arf4 expression is highest in the visceral endoderm but we did not detect cilia on these cells. In the visceral endoderm, the lack of Arf4 caused defects in cell structure and apical protein localization. This work suggests that while Arf4 is not required for ciliary assembly, it is important for the efficient transport of fibrocystin to cilia, and also plays critical roles in non-ciliary processes.

  8. Transition fibre protein FBF1 is required for the ciliary entry of assembled intraflagellar transport complexes.

    Science.gov (United States)

    Wei, Qing; Xu, Qingwen; Zhang, Yuxia; Li, Yujie; Zhang, Qing; Hu, Zeng; Harris, Peter C; Torres, Vicente E; Ling, Kun; Hu, Jinghua

    2013-01-01

    Sensory organelle cilia have critical roles in mammalian embryonic development and tissue homeostasis. Intraflagellar transport (IFT) machinery is required for the assembly and maintenance of cilia. Yet, how this large complex passes through the size-dependent barrier at the ciliary base remains enigmatic. Here we report that FBF1, a highly conserved transition fibre protein, is required for the ciliary import of assembled IFT particles at the ciliary base. We cloned dyf-19, the Caenorhabditis elegans homologue of human FBF1, in a whole-genome screen for ciliogenesis mutants. DYF-19 localizes specifically to transition fibres and interacts directly with the IFT-B component DYF-11/IFT54. Although not a structural component of transition fibres, DYF-19 is required for the transit of assembled IFT particles through the ciliary base. Furthermore, we found that human FBF1 shares conserved localization and function with its worm counterpart. We conclude that FBF1 is a key functional transition fibre component that actively facilitates the ciliary entry of assembled IFT machinery. PMID:24231678

  9. 25-Gauge pars plana vitrectomy for ciliary block (malignant) glaucoma.

    Science.gov (United States)

    Meng, Li; Wei, Wenbin; Li, Yanlong; Hui, Xiaoying; Han, Xiaodong; Shi, Xiaobo

    2015-08-01

    To evaluate the efficacy of 25-ga pars plana vitrectomy (PPV) and 25-ga PPV combined with phacoemulsification surgery for managing ciliary block (malignant) glaucoma. The medical records of 11 eyes, in nine consecutive patients with malignant glaucoma were retrospectively reviewed to determine the efficacy of 25-ga PPV for alleviating this disease. All phakic eyes underwent phacoemulsification surgery during vitrectomy. Control of intraocular pressure (IOP), pre- and postoperative best-corrected visual acuity (BCVA), and development of intra- and postoperative complications were evaluated during follow-up. Malignant glaucoma was promptly resolved, and recurrence was not observed during a mean follow-up period of 12.7 ± 3.2 (range 6-18) months. The mean IOP decreased from 35.9 ± 2.9 mmHg, preoperatively, to 16.0 ± 1.4 mmHg, measured at last visit (P = 0.013). Although IOP control was achieved in all eyes after surgery, two eyes required long-term topical antiglaucoma medication. The mean logarithm of the minimum angle of resolution BCVA improved from +0.69 ± 0.11, preoperatively, to +0.29 ± 0.07, postoperatively (P = 0.027). No severe intraoperative complications were observed. Postoperative complications mostly occurred during the first week after surgery, including transient corneal edema and Descemet's membrane folds in three eyes, fibrotic exudation in 2, local iris posterior synechia in 1, and transient hypotony in 1, which were resolved spontaneously or with medication. The 25-ga PPV procedure seems to be safe and effective for treating malignant glaucoma. Combined vitrectomy with phacoemulsification surgery and a staged surgical approach may improve the success rate. PMID:25062710

  10. Ammonia excretion in mytilid mussels is facilitated by ciliary beating.

    Science.gov (United States)

    Thomsen, J; Himmerkus, N; Holland, N; Sartoris, F J; Bleich, M; Tresguerres, M

    2016-08-01

    The excretion of nitrogenous waste products in the form of ammonia (NH3) and ammonium (NH4 (+)) is a fundamental process in aquatic organisms. For mytilid bivalves, little is known about the mechanisms and sites of excretion. This study investigated the localization and the mechanisms of ammonia excretion in mytilid mussels. An Rh protein was found to be abundantly expressed in the apical cell membrane of the plicate organ, which was previously described as a solely respiratory organ. The Rh protein was also expressed in the gill, although at significantly lower concentrations, but was not detectable in mussel kidney. Furthermore, NH3/NH4 (+) was not enriched in the urine, suggesting that kidneys are not involved in active NH3/NH4 (+) excretion. Exposure to elevated seawater pH of 8.5 transiently reduced NH3/NH4 (+) excretion rates, but they returned to control values following 24 h acclimation. These mussels had increased abundance of V-type H(+)-ATPase in the apical membranes of plicate organ cells; however, NH3/NH4 (+) excretion rates were not affected by the V-type H(+)-ATPase specific inhibitor concanamycin A (100 nmol l(-1)). In contrast, inhibition of ciliary beating with dopamine and increased seawater viscosity significantly reduced NH3 excretion rates under control pH (8.0). These results suggest that NH3/NH4 (+) excretion in mytilid mussels takes place by passive NH3 diffusion across respiratory epithelia via the Rh protein, facilitated by the water current produced for filter feeding, which prevents accumulation of NH3 in the boundary layer. This mechanism would be energy efficient for sessile organisms, as they already generate water currents for filter feeding. PMID:27489216

  11. Brachytherapy, A viable option of globe salvage in treatment of large ciliary body melanocytoma

    Directory of Open Access Journals (Sweden)

    Mahesh P Shanmugam

    2014-01-01

    Full Text Available We report a case of large histopathologically proven melanocytoma of the ciliary body in a 15-year-old male, presented with rapid extraocular growth following incisional biopsy with scleral patch graft. We chose brachytherapy with Ruthenium 106 plaque over enucleation as the later was refused by the parents. The initial apical height of the tumor was 14.2 mm on ultrasonography. Two weeks after brachytherapy, the mass regressed to a size of 8.1 mm and 1 year later to 6.7 mm. This is the first case report showing the response of brachytherapy to ciliary body melanocytoma, which results in ocular and visual acuity salvation with considerable decreased in size of the tumor. The authors conclude that brachytherapy is an option in the management of non-resectable melanocytoma of the ciliary body.

  12. Ciliary kinematics of Chlamydomonas reinhardtii in Complex Fluids: Role of viscosity

    Science.gov (United States)

    Gopinath, Arvind; Qin, Boyang; Arratia, Paulo

    2014-11-01

    The motility behavior of microorganisms can be significantly affected by the rheology of their fluidic environment. Guided by our experiments on the swimming gait of Chlamydomonas reinhardtii in viscoelastic fluids, we focus on ciliary waveforms in Newtonian fluids and systematically study the effect of increasing viscosity. We find that the beat frequency as well as the wave speed are both strongly influenced by fluid viscosity. Interestingly, ciliary waveforms at low viscosity show a larger influence of the cell body than waveforms at higher viscosity. We use slender body theory and principal component analysis to elucidate the role of fluid viscosity in regulating the kinematics of the swimming process.

  13. Intraguild predation and native lady beetle decline.

    Science.gov (United States)

    Gardiner, Mary M; O'Neal, Matthew E; Landis, Douglas A

    2011-01-01

    Coccinellid communities across North America have experienced significant changes in recent decades, with declines in several native species reported. One potential mechanism for these declines is interference competition via intraguild predation; specifically, increased predation of native coccinellid eggs and larvae following the introduction of exotic coccinellids. Our previous studies have shown that agricultural fields in Michigan support a higher diversity and abundance of exotic coccinellids than similar fields in Iowa, and that the landscape surrounding agricultural fields across the north central U.S. influences the abundance and activity of coccinellid species. The goal of this study was to quantify the amount of egg predation experienced by a native coccinellid within Michigan and Iowa soybean fields and explore the influence of local and large-scale landscape structure. Using the native lady beetle Coleomegilla maculata as a model, we found that sentinel egg masses were subject to intense predation within both Michigan and Iowa soybean fields, with 60.7% of egg masses attacked and 43.0% of available eggs consumed within 48 h. In Michigan, the exotic coccinellids Coccinella septempunctata and Harmonia axyridis were the most abundant predators found in soybean fields whereas in Iowa, native species including C. maculata, Hippodamia parenthesis and the soft-winged flower beetle Collops nigriceps dominated the predator community. Predator abundance was greater in soybean fields within diverse landscapes, yet variation in predator numbers did not influence the intensity of egg predation observed. In contrast, the strongest predictor of native coccinellid egg predation was the composition of edge habitats bordering specific fields. Field sites surrounded by semi-natural habitats including forests, restored prairies, old fields, and pasturelands experienced greater egg predation than fields surrounded by other croplands. This study shows that intraguild

  14. Intraguild predation and native lady beetle decline.

    Directory of Open Access Journals (Sweden)

    Mary M Gardiner

    Full Text Available Coccinellid communities across North America have experienced significant changes in recent decades, with declines in several native species reported. One potential mechanism for these declines is interference competition via intraguild predation; specifically, increased predation of native coccinellid eggs and larvae following the introduction of exotic coccinellids. Our previous studies have shown that agricultural fields in Michigan support a higher diversity and abundance of exotic coccinellids than similar fields in Iowa, and that the landscape surrounding agricultural fields across the north central U.S. influences the abundance and activity of coccinellid species. The goal of this study was to quantify the amount of egg predation experienced by a native coccinellid within Michigan and Iowa soybean fields and explore the influence of local and large-scale landscape structure. Using the native lady beetle Coleomegilla maculata as a model, we found that sentinel egg masses were subject to intense predation within both Michigan and Iowa soybean fields, with 60.7% of egg masses attacked and 43.0% of available eggs consumed within 48 h. In Michigan, the exotic coccinellids Coccinella septempunctata and Harmonia axyridis were the most abundant predators found in soybean fields whereas in Iowa, native species including C. maculata, Hippodamia parenthesis and the soft-winged flower beetle Collops nigriceps dominated the predator community. Predator abundance was greater in soybean fields within diverse landscapes, yet variation in predator numbers did not influence the intensity of egg predation observed. In contrast, the strongest predictor of native coccinellid egg predation was the composition of edge habitats bordering specific fields. Field sites surrounded by semi-natural habitats including forests, restored prairies, old fields, and pasturelands experienced greater egg predation than fields surrounded by other croplands. This study shows

  15. Role of intraguild predation in aphidophagous guilds

    Czech Academy of Sciences Publication Activity Database

    Hemptinne, J. L.; Magro, A.; Saladin, C.; Dixon, Anthony F. G.

    2012-01-01

    Roč. 136, č. 3 (2012), s. 161-170. ISSN 0931-2048 Institutional support: RVO:67179843 Keywords : aphidophagous guilds * cost of intraguild predation * interspecific predation * intraguild predation * ladybird beetles * omnivory Subject RIV: EH - Ecology, Behaviour Impact factor: 1.560, year: 2012

  16. Herbivory, Predation, and Biological Control.

    Science.gov (United States)

    Murphy, Terence M.; And Others

    1992-01-01

    Authors describe a set of controlled ecosystems that can be used to demonstrate the effects of herbivory on the health and growth of a plant population and of predation on the growth of a primary consumer population. The system also shows the effectiveness of biological pest control measures in a dramatic way. The construction of the ecosystems is…

  17. Membrane carbonic anhydrase (IV) and ciliary epithelium. Carbonic anhydrase activity is present in the basolateral membranes of the non-pigmented ciliary epithelium of rabbit eyes.

    Science.gov (United States)

    Matsui, H; Murakami, M; Wynns, G C; Conroy, C W; Mead, A; Maren, T H; Sears, M L

    1996-04-01

    Carbonic anhydrase inhibitors (CAIs) lower intraocular pressure by reducing aqueous flow. It has been thought that this pharmacologic reduction of aqueous flow is mediated by the ciliary epithelium, but it is not known whether this cellular action is effected by inhibition of the membranal (CA IV) and/or cytosolic (CA II) carbonic anhydrases of the ciliary epithelium. The isolated ciliary epithelial bilayer maintains its anatomic and functional polarity and generates a transepithelial potential difference (TEP) in an Ussing type chamber. Depletion of HCO3-, accomplished either with an HCO3(-)-free solution bathing the epithelial bilayer, or, with addition of freely permeant CAIs to HCO3(-)-containing media, (from either the PE or NPE side of the bilayer) depolarizes the preparation. Addition of CAIs to an HCO3(-)-depleted preparation has no further effect, indicating the specific action of the CAIs. The CAI, 2-p-NH2 benzenesulfonamido-1,3,4,-thiadiazole-5-SO2NH2, linked to polybutadiene maleic acid yields an impermeant polymer of 20000 Da with no loss of activity. At 45 microM this impermeant polymer caused a 60% increase in the SCC, seen only when the compound was applied to the NPE side of the bilayer. This latter result indicates an effect from inhibition of CA IV in the basolateral membranes of the NPE. Thus there are probably two different cellular actions of CAIs upon the ciliary epithelium to reduce aqueous inflow, cytoplasmic and membranal. The action of NPE basolateral membranal CA IV is probably linked to the chloride/bicarbonate exchanger. PMID:8795459

  18. Subtle cues of predation risk: starlings respond to a predator's direction of eye-gaze

    OpenAIRE

    Carter, Julia; Lyons, Nicholas J; Cole, Hannah L; Goldsmith, Arthur R

    2008-01-01

    For prey animals to negotiate successfully the fundamental trade-off between predation and starvation, a realistic assessment of predation risk is vital. Prey responses to conspicuous indicators of risk (such as looming predators or fleeing conspecifics) are well documented, but there should also be strong selection for the detection of more subtle cues. A predator's head orientation and eye-gaze direction are good candidates for subtle but useful indicators of risk, since many predators orie...

  19. How Predation Risk Shapes Avian Nest Site Selection and Processes Underlying Nest Predation Patterns

    OpenAIRE

    Latif, Quresh Shabbir

    2009-01-01

    Given the importance of nest predation to avian fitness, ornithologists expect birds to select nest sites that minimize predation risk. Despite numerous studies contributing to a large body of literature, how predation shapes avian nest site selection is not well understood largely because studies rarely examine the processes underlying either nest site selection or predation risk. I investigated how predation shapes nest site selection for a population of Yellow Warblers with an eye for the ...

  20. A Case of Incomplete Central Retinal Artery Occlusion Associated with Short Posterior Ciliary Artery Occlusion

    Directory of Open Access Journals (Sweden)

    Shinji Makino

    2013-01-01

    Full Text Available To our knowledge, incomplete central retinal artery occlusion associated with short posterior ciliary artery occlusion is extremely rare. Herein, we describe a case of a 62-year-old man who was referred to our hospital with of transient blindness in his right eye. At initial examination, the patient’s best-corrected visual acuity was 18/20 in the right eye. Fundus examination showed multiple soft exudates around the optic disc and mild macular retinal edema in his right eye; however, a cherry red spot on the macula was not detected. Fluorescein angiography revealed delayed dye inflow into the nasal choroidal hemisphere that is supplied by the short posterior ciliary artery. The following day, the patient’s visual acuity improved to 20/20. Soft exudates around the optic disc increased during observation and gradually disappeared. His hemodynamic parameters revealed subclavian steal syndrome as examined by cervical ultrasonography and digital subtraction angiography. We speculate that his transient blindness was due to ophthalmic artery spasms. In this particular case, spasms of the ophthalmic artery and occlusion of the short posterior ciliary artery occurred simultaneously. As the short posterior ciliary artery branches from the ophthalmic artery, the anatomical location of the lesion might be near the branching of both arteries.

  1. Characterization of a putative acetylcholine receptor in chick ciliary ganglion neurons

    International Nuclear Information System (INIS)

    Monoclonal antibodies to the main immunogenic region on the alpha subunit of acetylcholine receptors in muscle and electric organ recognize membrane components in chick brain and ciliary ganglia that are candidates for the neuronal receptor. The component in chick brain has been purified by immunoaffinity chromatography. It specifically binds nicotine but not alpha-bungarotoxin, and can be affinity labeled with (3H)bromoacetylcholine. The cross-reacting component in ciliary ganglion neurons is concentrated in synaptic membrane, and can be modulated by exposure of the cells to cholinergic ligands in culture. The cross-reacting component in ciliary ganglion neurons is an integral membrane component that binds concanavalin A, and it is distinct from the alpha-bungarotoxin binding component. The acetylcholine receptor function in these neurons can be locked by affinity alkylation with bromoacetylcholine, indicating similarity in this respect to receptors from muscle and electric organ. Antisera raised against the partially purified component from chick brain also block receptor function on ciliary ganglion neurons. The subcellular distribution of the ganglion component in culture is assessed, and it is shown that approximately 2/3 of the cross-reacting components are intracellular; the majority of these seem not to be destined for insertion into the plasma membrane

  2. ZMYND10 is mutated in primary ciliary dyskinesia and interacts with LRRC6

    DEFF Research Database (Denmark)

    Zariwala, Maimoona A; Gee, Heon Yung; Kurkowiak, Małgorzata;

    2013-01-01

    Defects of motile cilia cause primary ciliary dyskinesia (PCD), characterized by recurrent respiratory infections and male infertility. Using whole-exome resequencing and high-throughput mutation analysis, we identified recessive biallelic mutations in ZMYND10 in 14 families and mutations in the...

  3. Multicenter analysis of body mass index, lung function, and sputum microbiology in primary ciliary dyskinesia

    DEFF Research Database (Denmark)

    Maglione, Marco; Bush, Andrew; Nielsen, Kim G;

    2014-01-01

    BACKGROUND: No studies longitudinally, simultaneously assessed body mass index (BMI) and spirometry in primary ciliary dyskinesia (PCD). METHODS: We determined BMI and spirometry in 158 PCD children and adolescents from London, UK (n = 75), Naples, Italy (n = 23) and Copenhagen, Denmark (n = 60) ...

  4. Ciliary muscle contraction force and trapezius muscle activity during manual tracking of a moving visual target.

    Science.gov (United States)

    Domkin, Dmitry; Forsman, Mikael; Richter, Hans O

    2016-06-01

    Previous studies have shown an association of visual demands during near work and increased activity of the trapezius muscle. Those studies were conducted under stationary postural conditions with fixed gaze and artificial visual load. The present study investigated the relationship between ciliary muscle contraction force and trapezius muscle activity across individuals during performance of a natural dynamic motor task under free gaze conditions. Participants (N=11) tracked a moving visual target with a digital pen on a computer screen. Tracking performance, eye refraction and trapezius muscle activity were continuously measured. Ciliary muscle contraction force was computed from eye accommodative response. There was a significant Pearson correlation between ciliary muscle contraction force and trapezius muscle activity on the tracking side (0.78, p<0.01) and passive side (0.64, p<0.05). The study supports the hypothesis that high visual demands, leading to an increased ciliary muscle contraction during continuous eye-hand coordination, may increase trapezius muscle tension and thus contribute to the development of musculoskeletal complaints in the neck-shoulder area. Further experimental studies are required to clarify whether the relationship is valid within each individual or may represent a general personal trait, when individuals with higher eye accommodative response tend to have higher trapezius muscle activity. PMID:26746010

  5. Continued administration of ciliary neurotrophic factor protects mice from inflammatory pathology in experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Kuhlmann, Tanja; Remington, Leah; Cognet, Isabelle;

    2006-01-01

    Multiple sclerosis is an inflammatory disease of the central nervous system that leads to loss of myelin and oligodendrocytes and damage to axons. We show that daily administration (days 8 to 24) of murine ciliary neurotrophic factor (CNTF), a neurotrophic factor that has been described as a...

  6. Local excision of ciliary body tumors:a long-term prospective cohort study in China

    Institute of Scientific and Technical Information of China (English)

    WEI Wen-bin; YANG Wen-li; HU Shi-min; LI Bin

    2008-01-01

    Background Ciliary body tumors are usually difficult to diagnose and treat in early stages.However,treatment of such tumors has trended toward ocular conservation instead of enucleation.Local excision of ciliary body tumors has become effective with the development of the modern vitrectomy,but long-term outcomes are still not clear.Therefore,we reported the outcome of locally excised ciliary body tumors after long-term follow-up.Methods Twenty-two patients (22 eyes),who had been diagnosed with ciliary body tumors in Beijing Tongren Hospital from January 1996 to June 2001,were enrolled in this prospective cohort study.Localized lamellar sclera-ciliary excisions were performed.In some cases,vitrectomies,scleral graft transplantations,and further excisions of the anterior choroid were performed.Diagnoses were confirmed by histopathologic examination.Patients were followed from five to eleven years after surgery.Their visual acuity,intraocular pressure and local recurrence were recorded with descriptive percentages.Results After surgery,all patients maintained normal eyeball appearances.Six patients maintained circular pupils.The final best corrected visual acuities (BCVA) varied from 0.02-1.00,including 18 patients (81.82%) who had BCVA equal to or better than that before surgery.Fifteen patients (68.18%) had BCVA better than 0.3.Only two patients had intraocular pressure (IOP) of less than 10 mmHg and the other patients maintained normal IOP.Nine cases (40.91%) were given confirmed diagnosis of malignant melanoma,four (18.18%) of melanocytoma,six (27.27%) of nonpigmented ciliary epithelial adenoma,two (9.09%) of neurofibroma,and one (4.55%) of neurinoma.Twenty patients (90.91%) had no recurrence during the follow-up period.In one case melanocytoma recurred seven years after surgery and enucleation was performed.One patient,whose operation removed a malignant melanoma with a diameter of 16 mm,died of hepatic metastasis five years after the operation.Conclusion For

  7. Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda Crescimento das espécies de capim-colchão Digitaria ciliaris e Digitaria nuda

    Directory of Open Access Journals (Sweden)

    R.C. Souza

    2012-06-01

    Full Text Available The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods with four replications. Assessments began at 15 days after sowing (DAS, and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems, leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.O objetivo da presente pesquisa foi comparar o crescimento das espécies de capim colchão D. ciliaris e D. nuda, em condições não-competitivas. Para isso, foram conduzidos dois experimentos, um de março a julho de 2010 e outro de fevereiro a junho de 2011. O delineamento experimental de ambos os ensaios foi inteiramente casualizado, perfazendo um esquema fatorial (2 épocas x 2 espécies de capim colchão x 12 períodos de

  8. Predators reduce abundance and species richness of coral reef fish recruits via non-selective predation

    Science.gov (United States)

    Heinlein, J. M.; Stier, A. C.; Steele, M. A.

    2010-06-01

    Predators have important effects on coral reef fish populations, but their effects on community structure have only recently been investigated and are not yet well understood. Here, the effect of predation on the diversity and abundance of young coral reef fishes was experimentally examined in Moorea, French Polynesia. Effects of predators were quantified by monitoring recruitment of fishes onto standardized patch reefs in predator-exclosure cages or uncaged reefs. At the end of the 54-day experiment, recruits were 74% less abundant on reefs exposed to predators than on caged ones, and species richness was 42% lower on reefs exposed to predators. Effects of predators varied somewhat among families, however, rarefaction analysis indicated that predators foraged non-selectively among species. These results indicate that predation can alter diversity of reef fish communities by indiscriminately reducing the abundance of fishes soon after settlement, thereby reducing the number of species present on reefs.

  9. Effects of Behavioral Tactics of Predators on Dynamics of a Predator-Prey System

    Directory of Open Access Journals (Sweden)

    Hui Zhang

    2014-01-01

    Full Text Available A predator-prey model incorporating individual behavior is presented, where the predator-prey interaction is described by a classical Lotka-Volterra model with self-limiting prey; predators can use the behavioral tactics of rock-paper-scissors to dispute a prey when they meet. The predator behavioral change is described by replicator equations, a game dynamic model at the fast time scale, whereas predator-prey interactions are assumed acting at a relatively slow time scale. Aggregation approach is applied to combine the two time scales into a single one. The analytical results show that predators have an equal probability to adopt three strategies at the stable state of the predator-prey interaction system. The diversification tactics taking by predator population benefits the survival of the predator population itself, more importantly, it also maintains the stability of the predator-prey system. Explicitly, immediate contest behavior of predators can promote density of the predator population and keep the preys at a lower density. However, a large cost of fighting will cause not only the density of predators to be lower but also preys to be higher, which may even lead to extinction of the predator populations.

  10. Avian Predation by Captive Otters

    OpenAIRE

    Green R.

    2000-01-01

    During fifteen years of keeping otters, no predation on birds was observed until the winter of 1999-2000. Freshly killed birds offered to otters had not apparently been recognised as food. In the winter of 1999, a sub-adult captive otter stalked and killed a variety of birds - two pheasants, two gulls, a thrush and a goose. Otters in the adjacent pen caught and ate a heron.

  11. A nonadaptive scenario explaining the genetic predisposition to obesity: the "predation release" hypothesis.

    Science.gov (United States)

    Speakman, John R

    2007-07-01

    The "thrifty gene hypothesis" suggests we evolved genes for efficient food collection and fat deposition to survive periods of famine and that now that food is continuously available, these genes are disadvantageous because they make us obese in preparation for a famine that never comes. However, famines are relatively infrequent modern phenomena that involve insufficient mortality for thrifty genes to propagate. I suggest here that early hominids would have been subjected to stabilizing selection for body fatness, with obesity selected against by the risk of predation. Around two million years ago predation was removed as a significant factor by the development of social behavior, weapons, and fire. The absence of predation led to a change in the population distribution of body fatness due to random mutations and drift. Because this novel hypothesis involves random drift, rather than directed selection, it explains why, even in Western society, most people are not obese. PMID:17618852

  12. Optimal control of native predators

    Science.gov (United States)

    Martin, Julien; O'Connell, Allan F.; Kendall, William L.; Runge, Michael C.; Simons, Theodore R.; Waldstein, Arielle H.; Schulte, Shiloh A.; Converse, Sarah J.; Smith, Graham W.; Pinion, Timothy; Rikard, Michael; Zipkin, Elise F.

    2010-01-01

    We apply decision theory in a structured decision-making framework to evaluate how control of raccoons (Procyon lotor), a native predator, can promote the conservation of a declining population of American Oystercatchers (Haematopus palliatus) on the Outer Banks of North Carolina. Our management objective was to maintain Oystercatcher productivity above a level deemed necessary for population recovery while minimizing raccoon removal. We evaluated several scenarios including no raccoon removal, and applied an adaptive optimization algorithm to account for parameter uncertainty. We show how adaptive optimization can be used to account for uncertainties about how raccoon control may affect Oystercatcher productivity. Adaptive management can reduce this type of uncertainty and is particularly well suited for addressing controversial management issues such as native predator control. The case study also offers several insights that may be relevant to the optimal control of other native predators. First, we found that stage-specific removal policies (e.g., yearling versus adult raccoon removals) were most efficient if the reproductive values among stage classes were very different. Second, we found that the optimal control of raccoons would result in higher Oystercatcher productivity than the minimum levels recommended for this species. Third, we found that removing more raccoons initially minimized the total number of removals necessary to meet long term management objectives. Finally, if for logistical reasons managers cannot sustain a removal program by removing a minimum number of raccoons annually, managers may run the risk of creating an ecological trap for Oystercatchers.

  13. Coevolution can reverse predator-prey cycles.

    Science.gov (United States)

    Cortez, Michael H; Weitz, Joshua S

    2014-05-20

    A hallmark of Lotka-Volterra models, and other ecological models of predator-prey interactions, is that in predator-prey cycles, peaks in prey abundance precede peaks in predator abundance. Such models typically assume that species life history traits are fixed over ecologically relevant time scales. However, the coevolution of predator and prey traits has been shown to alter the community dynamics of natural systems, leading to novel dynamics including antiphase and cryptic cycles. Here, using an eco-coevolutionary model, we show that predator-prey coevolution can also drive population cycles where the opposite of canonical Lotka-Volterra oscillations occurs: predator peaks precede prey peaks. These reversed cycles arise when selection favors extreme phenotypes, predator offense is costly, and prey defense is effective against low-offense predators. We present multiple datasets from phage-cholera, mink-muskrat, and gyrfalcon-rock ptarmigan systems that exhibit reversed-peak ordering. Our results suggest that such cycles are a potential signature of predator-prey coevolution and reveal unique ways in which predator-prey coevolution can shape, and possibly reverse, community dynamics. PMID:24799689

  14. Predator-prey interactions mediated by prey personality and predator hunting mode.

    Science.gov (United States)

    Belgrad, Benjamin A; Griffen, Blaine D

    2016-04-13

    Predator-prey interactions are important drivers in structuring ecological communities. However, despite widespread acknowledgement that individual behaviours and predator species regulate ecological processes, studies have yet to incorporate individual behavioural variations in a multipredator system. We quantified a prevalent predator avoidance behaviour to examine the simultaneous roles of prey personality and predator hunting mode in governing predator-prey interactions. Mud crabs,Panopeus herbstii, reduce their activity levels and increase their refuge use in the presence of predator cues. We measured mud crab mortality and consistent individual variations in the strength of this predator avoidance behaviour in the presence of predatory blue crabs,Callinectes sapidus, and toadfish,Opsanus tau We found that prey personality and predator species significantly interacted to affect mortality with blue crabs primarily consuming bold mud crabs and toadfish preferentially selecting shy crabs. Additionally, the strength of the predator avoidance behaviour depended upon the predation risk from the predator species. Consequently, the personality composition of populations and predator hunting mode may be valuable predictors of both direct and indirect predator-prey interaction strength. These findings support theories postulating mechanisms for maintaining intraspecies diversity and have broad implications for community dynamics. PMID:27075257

  15. The Complex of Ciliary Neurotrophic Factor-Ciliary Neurotrophic Factor Receptor α Up-Regulates Connexin43 and Intercellular Coupling in Astrocytes via the Janus Tyrosine Kinase/Signal Transducer and Activator of Transcription PathwayD⃞

    OpenAIRE

    Ozog, Mark A.; Bernier, Suzanne M; Bates, Dave C.; Chatterjee, Bishwanath; Lo, Cecilia W.; Naus, Christian C.G.

    2004-01-01

    Cytokines regulate numerous cell processes, including connexin expression and gap junctional coupling. In this study, we examined the effect of ciliary neurotrophic factor (CNTF) on connexin43 (Cx43) expression and intercellular coupling in astrocytes. Murine cortical astrocytes matured in vitro were treated with CNTF (20 ng/ml), soluble ciliary neurotrophic factor receptor α (CNTFRα) (200 ng/ml), or CNTF-CNTFRα. Although CNTF and CNTFRα alone had no effect on Cx43 expression, the heterodimer...

  16. Population Variation in the Life History of a Land Fish, Alticus arnoldorum, and the Effects of Predation and Density.

    Science.gov (United States)

    Platt, Edward R M; Ord, Terry J

    2015-01-01

    Life history variation can often reflect differences in age-specific mortality within populations, with the general expectation that reproduction should be shifted away from ages experiencing increased mortality. Investigators of life history in vertebrates frequently focus on the impact of predation, but there is increasing evidence that predation may have unexpected impacts on population density that in turn prompt unexpected changes in life history. There are also other reasons why density might impact life history independently of predation or mortality more generally. We investigated the consequences of predation and density on life history variation among populations of the Pacific leaping blenny, Alticus arnoldorum. This fish from the island of Guam spends its adult life out of the water on rocks in the splash zone, where it is vulnerable to predation and can be expected to be sensitive to changes in population density that impact resource availability. We found populations invested more in reproduction as predation decreased, while growth rate varied primarily in response to population density. These differences in life history among populations are likely plastic given the extensive gene flow among populations revealed by a previous study. The influence of predation and density on life history was unlikely to have operated independently of each other, with predation rate tending to be associated with reduced population densities. Taken together, our results suggest predation and density can have complex influences on life history, and that plastic life history traits could allow populations to persist in new or rapidly changing environments. PMID:26398191

  17. Population Variation in the Life History of a Land Fish, Alticus arnoldorum, and the Effects of Predation and Density.

    Directory of Open Access Journals (Sweden)

    Edward R M Platt

    Full Text Available Life history variation can often reflect differences in age-specific mortality within populations, with the general expectation that reproduction should be shifted away from ages experiencing increased mortality. Investigators of life history in vertebrates frequently focus on the impact of predation, but there is increasing evidence that predation may have unexpected impacts on population density that in turn prompt unexpected changes in life history. There are also other reasons why density might impact life history independently of predation or mortality more generally. We investigated the consequences of predation and density on life history variation among populations of the Pacific leaping blenny, Alticus arnoldorum. This fish from the island of Guam spends its adult life out of the water on rocks in the splash zone, where it is vulnerable to predation and can be expected to be sensitive to changes in population density that impact resource availability. We found populations invested more in reproduction as predation decreased, while growth rate varied primarily in response to population density. These differences in life history among populations are likely plastic given the extensive gene flow among populations revealed by a previous study. The influence of predation and density on life history was unlikely to have operated independently of each other, with predation rate tending to be associated with reduced population densities. Taken together, our results suggest predation and density can have complex influences on life history, and that plastic life history traits could allow populations to persist in new or rapidly changing environments.

  18. Predator recognition in rainbowfish, Melanotaenia duboulayi, embryos.

    Directory of Open Access Journals (Sweden)

    Lois Jane Oulton

    Full Text Available Exposure to olfactory cues during embryonic development can have long term impacts on birds and amphibians behaviour. Despite the vast literature on predator recognition and responses in fishes, few researchers have determined how fish embryos respond to predator cues. Here we exposed four-day-old rainbowfish (Melanotaenia duboulayi embryos to cues emanating from a novel predator, a native predator and injured conspecifics. Their response was assessed by monitoring heart rate and hatch time. Results showed that embryos have an innate capacity to differentiate between cues as illustrated by faster heart rates relative to controls. The greatest increase in heart rate occurred in response to native predator odour. While we found no significant change in the time taken for eggs to hatch, all treatments experienced slight delays as expected if embryos are attempting to reduce exposure to larval predators.

  19. Effect of cAMP on short-circuit current in isolated human ciliary body

    Institute of Scientific and Technical Information of China (English)

    WU Ren-yi; MA Ning; HU Qian-qian

    2013-01-01

    Background Cyclic adenosine monophosphate (cAMP) could activate chloride channels in bovine ciliary body and trigger an increase in the ionic current (short-circuit current,Isc) across the ciliary processes in pigs.The purpose of this study was to investigate how cAMP modulates Isc in isolated human ciliary processes and the possible involvement of chloride transport across the tissue in cAMP-induced Isc change.Methods In an Ussing-type chamber system,the Isc changes induced by the cAMP analogue 8-bromo-cAMP and an adenylyl cyclase activator forskolin in isolated human ciliary processes were assessed.The involvement of Cl-component in the bath solution was investigated.The effect of Cl-channel (10 μmol/L niflumic acid and 1 mmol/L 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS)),K+ channel (10 mmol/L tetraethylammonium chloride (TEA)),or Na+ channel blockers (1 mmol/L amiloride) on 8-bromo-cAMP-induced Isc change was also studied.Results Dose-dependently,8-bromo-cAMP (10 nmol/L-30 μmol/L) or forskolin (10 nmol/L-3 μmol/L) increased Isc across the ciliary processes with an increase in negative potential difference on the non-pigmented epithelium (NPE) side of the tissue.Isc increase induced by 8-bromo-cAMP was more pronounced when the drug was applied on the NPE side than on the pigmented epithelium side.When the tissue was bathed in low Cl-solutions,the Isc increase was significantly inhibited.Finally,niflumic acid and DIDS,but not TEA or amiloride,significantly prevented the Isc increase induced by 8-bromo-cAMP.Conclusions cAMP stimulates stroma-to-aqueous anionic transport in isolated human ciliary processes.Chloride is likely to be among the ions,the transportation of which across the tissue is triggered by cAMP,suggesting the potential role of cAMP in the process of aqueous humor formation in human eyes.

  20. Predator-specific camouflage in chameleons

    OpenAIRE

    Stuart-Fox, Devi; Moussalli, Adnan; Martin J Whiting

    2008-01-01

    A crucial problem for most animals is how to deal with multiple types of predator, which differ in their sensory capabilities and methods of prey detection. For animals capable of rapid colour change, one potential strategy is to change their appearance in relation to the threat posed by different predators. Here, we show that the dwarf chameleon, Bradypodion taeniabronchum, exhibits different colour responses to two predators that differ in their visual capabilities. Using a model of animal ...

  1. What regulates crab predation on mangrove propagules?

    OpenAIRE

    Van Nedervelde, F.; S.Cannicci; Koedam, N.; Bosire, J.; F. Dahdouh-Guebas

    2015-01-01

    Crabs play a major role in some ecosystems. To increase our knowledge about the factors that influence crab predation on propagules in mangrove forests, we performed experiments in Gazi Bay, Kenya in July 2009. We tested whether: (1) crab density influences propagule predation rate; (2) crab size influences food competition and predation rate; (3) crabs depredate at different rates according to propagule and canopy cover species; (4) vegetation density is correlated with crab density; (5) foo...

  2. Bardet–Biedl syndrome proteins 1 and 3 regulate the ciliary trafficking of polycystic kidney disease 1 protein

    OpenAIRE

    Su, Xuefeng; Driscoll, Kaitlin; Yao, Gang; Raed, Anas; Wu, Maoqing; Beales, Philip L.; Zhou, Jing

    2014-01-01

    Bardet–Biedl syndrome (BBS) and autosomal dominant polycystic kidney disease (ADPKD) are two genetically distinct ciliopathies but share common phenotypes such as renal cysts. Seven BBS proteins form a complex called the BBSome which is localized at the basal body or ciliary axoneme and regulates the ciliary entry or flagellar exit of several signaling molecules. Here, we demonstrate that, unlike the seven-span somatostatin receptor 3 or the leptin receptor that interacts with all subunits of...

  3. Renin-angiotensin system expression and secretory function in cultured human ciliary body non-pigmented epithelium

    OpenAIRE

    Cullinane, A B; Leung, P S; Ortego, J.; Coca-Prados, M; Harvey, B J

    2002-01-01

    Background: Renin-angiotensin system (RAS) components have been identified in human ciliary body and aqueous humour, pointing to a role for the RAS in the regulation of aqueous humour dynamics. Here, the authors examine the functional expression of a RAS and the effects of angiotensin II (AII) on a signal transduction pathway and ion secretion mechanism in cultured human ciliary body non-pigmented epithelium (HNPE).

  4. Voltage-gated potassium channel Kvl.3 in rabbit ciliary epithelium regulates the membrane potential via coupling intracellular calcium

    Institute of Scientific and Technical Information of China (English)

    LI Yan-feng; ZHUO Ye-hong; BI Wei-na; BAI Yu-jing; LI Yan-na; WANG Zhi-jian

    2008-01-01

    Background The cell layer of the ciliary epithelium is responsible for aqueous humor secretion and maintenance.Ion channels play an important role in these processes.The main aim of this study was to determine whether the well-characterized members of the Kvl family (Kv1.3) contribute to the Kv currents in ciliary epithelium.Methods New Zealand White rabbits were maintained in a 12 hours light/dark cycle.Ciliary epithelium samples were isolated from the rabbits.We used Western blotting and immunocytochemistry to identify the expression and location of a voltage-gated potassium channel Kvl.3 in ciliary body epithelium.Membrane potential change after adding of Kv1.3 inhibitor margatoxin (MgTX) was observed with a fluorescence method.Results Western blotting and immunocytochemical studies showed that the Kv1.3 protein expressed in pigment ciliary epithelium and nonpigment ciliary epithelium,however it seemed to express more in the apical membrane of the nonpigmented epithelial cells.One nmol/L margatoxin,a specific inhibitor of Kv1.3 channels caused depolarization of the cultured nonpigmented epithelium (NPE) membrane potential.The cytosotic calcium increased after NPE cell depolarization,this increase of cytosolic calcium was partially blocked by 12.5 μmol/L dantrolene and 10 μmol/L nifedipine.These observations suggest that Kv1.3 channels modulate ciliary epithelium potential and effect calcium dependent mechanisms.Conclusion Kv1.3 channels contribute to K+ efflux at the membrane of rabbit ciliary epithelium.

  5. Species Diversity Enhances Predator Growth Rates

    Directory of Open Access Journals (Sweden)

    Mark H. Olson

    2007-01-01

    Full Text Available Predators can be important top-down regulators of community structure and are known to have both positive and negative effects on species diversity. However, little is known about the reciprocal effects of species diversity on predators. Across a set of 80 lakes in Connecticut, USA, we found a strong positive correlation between prey species diversity (using the Shannon-Weiner Diversity Index and growth rates of largemouth bass (Micropterus salmoides. This correlation was strongest for small predators and decreased with body size. Although the underlying mechanisms are not known, the correlation is not driven by total fish abundance, predator abundance, or productivity.

  6. Ontogenetic specialism in predators with multiple niche shifts prevents predator population recovery and establishment

    OpenAIRE

    van, Leeuwen, M.; Huss, M.; Gårdmark, A.; Roos,, Markus

    2014-01-01

    The effects of ontogenetic niche shifts on community structure and dynamics are underexplored, despite the occurrence of such shifts in the majority of animal species. We studied the form of niche shifts in a predator that exhibits multiple ontogenetic niche shifts, and analyzed how this life history complexity affects the size-structured predator-prey dynamics in the system. The predator represents either an ontogenetic generalist, exhibiting a partial shift to predation (in which case an al...

  7. Sex-Biased Predation on Taricha by a Novel Predator in Annadel State Park

    OpenAIRE

    Brouillette, Amber Noelle

    2008-01-01

    Newts of the genus Taricha have long been studied due to the powerful neurotoxin found in their skin. Tetrodotoxin (TTX) acts by blocking receptors in sodium channels, ultimately resulting in death via asphyxiation. The only documented predators of species in this genus have been snakes of the genus Thamnophis. Recently, predation on Taricha in Ledson Marsh in Annadel State Park, Santa Rosa, CA was discovered. Predation was in the form of laceration or evisceration, and tracking of predation ...

  8. Evidence for two extremes of ciliary motor response in a single swimming microorganism.

    Science.gov (United States)

    Jung, Ilyong; Powers, Thomas R; Valles, James M

    2014-01-01

    Because arrays of motile cilia drive fluids for a range of processes, the versatile mechano-chemical mechanism coordinating them has been under scrutiny. The protist Paramecium presents opportunities to compare how groups of cilia perform two distinct functions, swimming propulsion and nutrient uptake. We present how the body cilia responsible for propulsion and the oral-groove cilia responsible for nutrient uptake respond to changes in their mechanical environment accomplished by varying the fluid viscosity over a factor of 7. Analysis with a phenomenological model of trajectories of swimmers made neutrally buoyant with magnetic forces combined with high-speed imaging of ciliary beating reveal that the body cilia exert a nearly constant propulsive force primarily by reducing their beat frequency as viscosity increases. By contrast, the oral-groove cilia beat at a nearly constant frequency. The existence of two extremes of motor response in a unicellular organism prompts unique investigations of factors controlling ciliary beating. PMID:24411242

  9. Downstream collecting in ciliary suspension feeders: the catch-up principle

    DEFF Research Database (Denmark)

    Riisgård, Hans Ulrik; Nielsen, Claus; Larsen, Poul Scheel

    2000-01-01

    Based on observations of feeding structures and currents in the polychaete Spirorbis tridentatus, the entoproct Loxosoma pectinaricola and the cycliophore Symbion pandora, which all possess compound cilia, it is hypothesized that their capture mechanism is based on the catch-up principle. According...... to this principle, the compound cilia constitute the pump which generates a flow with suspended particles that enters the ciliary region. In this region the same cilia, during their power stroke, catch up with suspended particles and transfer the particles to a food groove, or a mouth cavity. In the...... the ciliary bands of some rotifers and of the various types of trochophora larvae of annelids, molluscs and entoprocts, it is hypothesized that the feeding mechanisms of these organisms are based on the catch-up principle....

  10. Ciliary and mucus-net filter feeding, with special reference to fluid mechanical characteristics

    DEFF Research Database (Denmark)

    Jørgensen, C.B.; Kiørboe, Thomas; Møhlenberg, F.;

    1984-01-01

    Filter characteristics were determined and compared in ciliary and mucus-net filter feeders. The ciliary feeders include the polychaete Sabella penicillus, the brachiopod Terebratulina retusa, the marine bivalves Monia squama, Cardium glaucum, and Petricola pholadiformis, and the freshwater...... bivalves Dreissena polymorpha, Unio pictorum and Anodonta cygnea. The mucus-net feeders are the polychaete Chaetopterus variopedatus, the gastropod Crepidula fornicata and the ascidians Styela clava, Ciona intestinalis, Ascidia virginea, A. obliqua and A. mentula. Efficiencies of particle retention as a...... function of particle size was determined by counting of particles in samples of inhalant and exhalant water. The lower threshold for efficient particle retention varied from .apprx. 6 .mu.m in T. retuso to .apprx. 1 .mu.m in D. polymorpha. Mucus nets efficiently retained particles down to 1-2 .mu.m. Filter...

  11. Circulating levels of ciliary neurotrophic factor in normal pregnancy and preeclampsia

    OpenAIRE

    Akahori, Yoichiro; Takamoto, Norio; Masumoto,Akio; Inoue,Seiji; Nakatsukasa, Hideki; MASUYAMA, HISASHI; Hiramatsu,Yuji

    2010-01-01

    Ciliary neurotrophic factor (CNTF) has been shown to decrease food intake in mouse models of obesity and to improve insulin sensitivity. It is well known that tight regulation of glucose metabolism is essential for successful gestational outcomes (e.g. fetal growth), and that abnormal insulin resistance is associated with preeclampsia (PE). To investigate the possibility that CNTF might be involved in the regulation of insulin resistance during pregnancy, circulating levels of CNTF w...

  12. Ciliary neurotrophic factor has intrinsic and extrinsic roles in regulating B cell differentiation and bone structure.

    OpenAIRE

    Maria Askmyr; White, Kirby E; Tanja Jovic; King, Hannah A.; Quach, Julie M.; Maluenda, Ana C.; Baker, Emma K; Smeets, Monique F.; Walkley, Carl R.; Purton, Louise E.

    2015-01-01

    The gp130 receptor and its binding partners play a central role in cytokine signalling. Ciliary neurotrophic factor (CNTF) is one of the cytokines that signals through the gp130 receptor complex. CNTF has previously been shown to be a negative regulator of trabecular bone remodelling and important for motor neuron development. Since haematopoietic cell maintenance and differentiation is dependent on the bone marrow (BM) microenvironment, where cells of the osteoblastic lineage are important r...

  13. Expression of ciliary neurotrophic factor and its receptor in experimental obstructive nephropathy

    OpenAIRE

    Lee, Byoung-Seung; Choi, Jae-Youn; Cha, Jung-Ho

    2011-01-01

    Ciliary neurotrophic factor (CNTF) is well known as a growth/survival factor of neuronal tissue. We investigated the expression of CNTF and its specific receptor alpha (CNTFRα) in a unilateral ureteral obstruction (UUO) model. Complete UUO was produced by left ureteral ligation in Sprague-Dawley rats. The animals were sacrificed on days 1, 3, 5, 7, 14, 21, and 28 after UUO. The kidneys were fixed, and processed for both immunohistochemistry and in situ hybridization. CNTF immunoreactivity in ...

  14. Perivascular Cells Increase Expression of Ciliary Neurotrophic Factor Following Partial Denervation of the Rat Neurohypophysis

    OpenAIRE

    Lo, David; SunRhodes, Neil; Watt, John A.

    2008-01-01

    The expression of ciliary neurotrophic factor (CNTF) was investigated immunocytochemically during the axonal degeneration and collateral axonal sprouting response that follows partial denervation of the rat neurohypophysis. A significant increase in the number of CNTF-immunoreactive (CNTF-ir) cells was observed in the neurohypophysis of partially denervated animals compared to age-matched sham-operated controls by 5 days post-denervation, remaining elevated throughout the 30 day post denervat...

  15. Crystal structure of dimeric human ciliary neurotrophic factor determined by MAD phasing.

    OpenAIRE

    McDonald, N. Q.; Panayotatos, N; Hendrickson, W A

    1995-01-01

    Ciliary neurotrophic factor (CNTF) promotes the survival and differentiation of developing motor neurons and is a potential therapeutic for treating neurodegeneration and nerve injury. The crystal structure of human CNTF has been determined at 2.4 A resolution using multi-wavelength anomalous diffraction (MAD) phasing from a single Yb3+ ions. The structure reveals that CNTF is dimeric, with a novel anti-parallel arrangement of the subunits, not previously observed for other cytokines. Each su...

  16. Ciliary Neurotrophic Factor Protects Striatal Neurons against Excitotoxicity by Enhancing Glial Glutamate Uptake

    OpenAIRE

    Beurrier, Corinne; Faideau, Mathilde; Bennouar, Khaled-Ezaheir; Escartin, Carole; Kerkerian-Le Goff, Lydia; Bonvento, Gilles; Gubellini, Paolo

    2010-01-01

    Ciliary neurotrophic factor (CNTF) is a potent neuroprotective cytokine in different animal models of glutamate-induced excitotoxicity, although its action mechanisms are still poorly characterized. We tested the hypothesis that an increased function of glial glutamate transporters (GTs) could underlie CNTF-mediated neuroprotection. We show that neuronal loss induced by in vivo striatal injection of the excitotoxin quinolinic acid (QA) was significantly reduced (by ∼75%) in CNTF-treated anima...

  17. Ciliary neurotrophic factor prevents the degeneration of motor neurons in mouse mutant progressive motor neuronopathy

    OpenAIRE

    Sendtner, Michael; Stöckli, Kurt A.; Thoenen, Hans; Schmalbruch, H.; Carroll, P.; Kreutzberg, Georg W.

    2010-01-01

    CILIARY neurotrophic factor (CNTF) supports the survival of embryonic motor neurons in vitro and in vivo and prevents lesion-mediated degeneration of rat motor neuron~ during early post-natal stages. Here we report that CNTF greatly reduces all the functional and morphological changes in pmnlpmn mice5, an autosomal recessive mutant leading to progressive caudo-cranial motor neuron degeneration. The first manifestations of progressive motor neuronopathy in homozygous pmnl pmn mice become appar...

  18. Continued Administration of Ciliary Neurotrophic Factor Protects Mice from Inflammatory Pathology in Experimental Autoimmune Encephalomyelitis

    OpenAIRE

    Kuhlmann, Tanja; Remington, Leah; Cognet, Isabelle; Bourbonniere, Lyne; Zehntner, Simone; Guilhot, Florence; Herman, Alexandra; Guay-Giroux, Angélique; Antel, Jack P.; Owens, Trevor; Gauchat, Jean-François

    2006-01-01

    Multiple sclerosis is an inflammatory disease of the central nervous system that leads to loss of myelin and oligodendrocytes and damage to axons. We show that daily administration (days 8 to 24) of murine ciliary neurotrophic factor (CNTF), a neurotrophic factor that has been described as a survival and differentiation factor for neurons and oligodendrocytes, significantly ameliorates the clinical course of a mouse model of multiple sclerosis. In the acute phase of experimental autoimmune en...

  19. Ciliary neurotrophic factor corrects obesity and diabetes associated with leptin deficiency and resistance

    OpenAIRE

    Gloaguen, Isabelle; Costa, Patrizia; Demartis, Anna; Lazzaro, Domenico; Di Marco, Annalise; Graziani, Rita; Paonessa, Giacomo; Chen, Fang; Rosenblum, Charles I.; Van der Ploeg, Lex H. T.; Cortese, Riccardo; Ciliberto, Gennaro; Laufer, Ralph

    1997-01-01

    Receptor subunits for the neurocytokine ciliary neurotrophic factor (CNTF) share sequence similarity with the receptor for leptin, an adipocyte-derived cytokine involved in body weight homeostasis. We report here that CNTF and leptin activate a similar pattern of STAT factors in neuronal cells, and that mRNAs for CNTF receptor subunits, similarly to the mRNA of leptin receptor, are localized in mouse hypothalamic nuclei involved in the regulation of energy balance. Systemic administration of ...

  20. Ciliary neurotrophic factor prevents degeneration of adult rat substantia nigra dopaminergic neurons in vivo.

    OpenAIRE

    T. Hagg; Varon, S

    1993-01-01

    We have investigated the neuroprotective effects of recombinant human ciliary neurotrophic factor (CNTF) for injured dopaminergic neurons of the adult rat substantia nigra compacta. Fourteen days after a unilateral transection of the nigrostriatal pathway two-thirds of the neurons (identified by retrograde labeling) had degenerated. In sharp contrast, 73% (a few cases, > 90%) of this cell loss was prevented by continuous infusion of CNTF close to the injured neurons. However, CNTF did not pre...

  1. The isolated ciliary bilayer is useful for studies of aqueous humor formation.

    OpenAIRE

    Sears, M L; Yamada, E.; Cummins, D; Mori, N; Mead, A.; Murakami, M.

    1991-01-01

    An intact ciliary epithelial bilayer has been isolated from the rabbit eye by perfusion, microsurgical dissection, and recovery techniques. Vital subcellular organelles and intercellular junctions of this epithelial bilayer preparation are very well preserved. The total electrical resistance of the epithelial bilayer is 350 ohms, and the transepithelial potential is 650 microV, nonpigmented epithelium side negative. The electrical resistance is reduced by 0.2 mM EGTA and the transepithelial p...

  2. Rootletin organizes the ciliary rootlet to achieve neuron sensory function in Drosophila

    OpenAIRE

    Chen, Jieyan V.; Kao, Ling-Rong; Jana, Swadhin C.; Sivan-Loukianova, Elena; Mendonça, Susana; Cabrera, Oscar A.; Singh, Priyanka; Cabernard, Clemens; Eberl, Daniel F.; Bettencourt-Dias, Monica; Timothy L. Megraw

    2015-01-01

    Cilia are essential for cell signaling and sensory perception. In many cell types, a cytoskeletal structure called the ciliary rootlet links the cilium to the cell body. Previous studies indicated that rootlets support the long-term stability of some cilia. Here we report that Drosophila melanogaster Rootletin (Root), the sole orthologue of the mammalian paralogs Rootletin and C-Nap1, assembles into rootlets of diverse lengths among sensory neuron subtypes. Root mutant neurons lack rootlets a...

  3. Predation efficiency of Anopheles gambiae larvae by aquatic predators in western Kenya highlands

    Directory of Open Access Journals (Sweden)

    Nyindo Mramba

    2011-07-01

    Full Text Available Abstract Background The current status of insecticide resistance in mosquitoes and the effects of insecticides on non-target insect species have raised the need for alternative control methods for malaria vectors. Predation has been suggested as one of the important regulation mechanisms for malaria vectors in long-lasting aquatic habitats, but the predation efficiency of the potential predators is largely unknown in the highlands of western Kenya. In the current study, we examined the predation efficiency of five predators on Anopheles gambiae s.s larvae in 24 hour and semi- field evaluations. Methods Predators were collected from natural habitats and starved for 12 hours prior to starting experiments. Preliminary experiments were conducted to ascertain the larval stage most predated by each predator species. When each larval instar was subjected to predation, third instar larvae were predated at the highest rate. Third instar larvae of An. gambiae were introduced into artificial habitats with and without refugia at various larval densities. The numbers of surviving larvae were counted after 24 hours in 24. In semi-field experiments, the larvae were counted daily until they were all either consumed or had developed to the pupal stage. Polymerase chain reaction was used to confirm the presence of An. gambiae DNA in predator guts. Results Experiments found that habitat type (P P P P An. gambiae DNA was found in at least three out of ten midguts for all predator species. Gambusia affins was the most efficient, being three times more efficient than tadpoles. Conclusion These experiments provide insight into the efficiency of specific natural predators against mosquito larvae. These naturally occurring predators may be useful in biocontrol strategies for aquatic stage An. gambiae mosquitoes. Further investigations should be done in complex natural habitats for these predators.

  4. Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird

    Science.gov (United States)

    Hollander, Franck A.; Van Dyck, Hans; San Martin, Gilles; Titeux, Nicolas

    2015-01-01

    In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio) that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments. PMID:26624619

  5. Otx1 gene-controlled morphogenesis of the horizontal semicircular canal and the origin of the gnathostome characteristics.

    Science.gov (United States)

    Mazan, S; Jaillard, D; Baratte, B; Janvier, P

    2000-01-01

    The horizontal semicircular canal of the inner ear is a unique feature of gnathostomes and is predated by the two vertical semicircular canals, which are already present in lampreys and some fossil, armored jawless vertebrates regarded as close relatives of gnathostomes. Inactivation in mice of the orthodenticle-related gene Otx1 results in the absence of this structure. In bony fishes and tetrapods (osteichthyans), this gene belongs to a small multigene family comprising at least two orthology classes, Otx1 and Otx2. We report that, as in the mouse, xenopus and zebrafish, Otx1- and Otx2-related genes are present in a chondrichthyan, the dogfish Scyliorhinus canicula, with an Otx1 expression domain in the otocyst very similar to those observed in osteichthyans. A strong correlation is thus observed in extant vertebrates between the distribution of the horizontal semicircular canal and the presence of an Otx1 ortholog expressed in the inner ear, which supports the hypothesis that the absence of this characteristic in Otx1-/- mice may correspond to an atavism. The same conclusion applies to two other gnathostome-specific characteristics also deleted in Otx1-/- mice, the utriculosaccular duct and the ciliary process. Together with functional analyses of Otx1 and Otx2 genes in mice and comparative analyses of the Otx gene families characterized in chordates, these discoveries lead to the hypothesis that some of the anatomic characteristics of gnathostomes have appeared quite suddenly and almost simultaneously in vertebrate evolution, possibly as a consequence of gene functional diversifications following duplications of an ancestral chordate gene. PMID:11252561

  6. Chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor promotes sciatic nerve repair.

    Science.gov (United States)

    Zhang, Yanru; Zhang, Hui; Katiella, Kaka; Huang, Wenhua

    2014-07-15

    A chemically extracted acellular allogeneic nerve graft can reduce postoperative immune rejection, similar to an autologous nerve graft, and can guide neural regeneration. However, it remains poorly understood whether a chemically extracted acellular allogeneic nerve graft combined with neurotrophic factors provides a good local environment for neural regeneration. This study investigated the repair of injured rat sciatic nerve using a chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor. An autologous nerve anastomosis group and a chemical acellular allogeneic nerve bridging group were prepared as controls. At 8 weeks after repair, sciatic functional index, evoked potential amplitude of the soleus muscle, triceps wet weight recovery rate, total number of myelinated nerve fibers and myelin sheath thickness were measured. For these indices, values in the three groups showed the autologous nerve anastomosis group > chemically extracted acellular nerve graft + ciliary neurotrophic factor group > chemical acellular allogeneic nerve bridging group. These results suggest that chemically extracted acellular nerve grafts combined with ciliary neurotrophic factor can repair sciatic nerve defects, and that this repair is inferior to autologous nerve anastomosis, but superior to chemically extracted acellular allogeneic nerve bridging alone. PMID:25221592

  7. Chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor promotes sciatic nerve repair

    Institute of Scientific and Technical Information of China (English)

    Yanru Zhang; Hui Zhang; Kaka Katiella; Wenhua Huang

    2014-01-01

    A chemically extracted acellular allogeneic nerve graft can reduce postoperative immune re-jection, similar to an autologous nerve graft, and can guide neural regeneration. However, it remains poorly understood whether a chemically extracted acellular allogeneic nerve graft combined with neurotrophic factors provides a good local environment for neural regenera-tion. This study investigated the repair of injured rat sciatic nerve using a chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor. An autologous nerve anastomosis group and a chemical acellular allogeneic nerve bridging group were prepared as controls. At 8 weeks after repair, sciatic functional index, evoked potential amplitude of the soleus muscle, triceps wet weight recovery rate, total number of myelinated nerve fibers and myelin sheath thickness were measured. For these indices, values in the three groups showed the autologous nerve anastomosis group > chemically extracted acellular nerve graft + ciliary neurotrophic factor group > chemical acellular allogeneic nerve bridging group. These results suggest that chemically extracted acellular nerve grafts combined with ciliary neurotrophic factor can repair sciatic nerve defects, and that this repair is inferior to autologous nerve anasto-mosis, but superior to chemically extracted acellular allogeneic nerve bridging alone.

  8. LRRC6 mutation causes primary ciliary dyskinesia with dynein arm defects.

    Directory of Open Access Journals (Sweden)

    Amjad Horani

    Full Text Available Despite recent progress in defining the ciliome, the genetic basis for many cases of primary ciliary dyskinesia (PCD remains elusive. We evaluated five children from two unrelated, consanguineous Palestinian families who had PCD with typical clinical features, reduced nasal nitric oxide concentrations, and absent dynein arms. Linkage analyses revealed a single common homozygous region on chromosome 8 and one candidate was conserved in organisms with motile cilia. Sequencing revealed a single novel mutation in LRRC6 (Leucine-rich repeat containing protein 6 that fit the model of autosomal recessive genetic transmission, leading to a change of a highly conserved amino acid from aspartic acid to histidine (Asp146His. LRRC6 was localized to the cytoplasm and was up-regulated during ciliogenesis in human airway epithelial cells in a Foxj1-dependent fashion. Nasal epithelial cells isolated from affected individuals and shRNA-mediated silencing in human airway epithelial cells, showed reduced LRRC6 expression, absent dynein arms, and slowed cilia beat frequency. Dynein arm proteins were either absent or mislocalized to the cytoplasm in airway epithelial cells from a primary ciliary dyskinesia subject. These findings suggest that LRRC6 plays a role in dynein arm assembly or trafficking and when mutated leads to primary ciliary dyskinesia with laterality defects.

  9. Ruthenium-106 brachytherapy, local resection and pars plana vitrectomy for a ciliary body melanoma

    International Nuclear Information System (INIS)

    This case report deals with brachytherapy, subsequent local resection and pars plana vitrectomy for a large ciliary body melanoma. In 1990 a 6 mm high ciliary body melanoma was treated with Ruthenium 106. In spite of early regression of the tumour infiltrating the choroid the remaining ciliary body melanoma was removed by local resection with simultaneous cataract surgery and anterior vitrectomy. 6 months later a focal PVR retinal detachment at the site of the scar of the Ruthenium-106 plaque developed and was treated by vitrectomy, membrane peeling and SF-6 gas tamponade. After 1 year of follow up the retina remained reattached, the tumor had regressed to a chorioatrophic scar. Internal examination could not reveal any sign of metastasis, visual acuity was 1/36 due to a maculopathy. Regarding to our knowledge of cell biology development of metastasis is a much more complex procedure than pure mechanical dissemination of tumor cells. In our opinion cataract or even vitreoretinal surgery may be justified in case of a necrotic tumor. (authors)

  10. Long-term clearance from small airways in subjects with ciliary dysfunction

    Directory of Open Access Journals (Sweden)

    Hjelte Lena

    2006-05-01

    Full Text Available Abstract The objective of this study was to investigate if long-term clearance from small airways is dependent on normal ciliary function. Six young adults with primary ciliary dyskinesia (PCD inhaled 111 Indium labelled Teflon particles of 4.2 μm geometric and 6.2 μm aerodynamic diameter with an extremely slow inhalation flow, 0.05 L/s. The inhalation method deposits particles mainly in the small conducting airways. Lung retention was measured immediately after inhalation and at four occasions up to 21 days after inhalation. Results were compared with data from ten healthy controls. For additional comparison three of the PCD subjects also inhaled the test particles with normal inhalation flow, 0.5 L/s, providing a more central deposition. The lung retention at 24 h in % of lung deposition (Ret24 was higher (p 24 with slow inhalation flow was 73.9 ± 1.9 % compared to 68.9 ± 7.5 % with normal inhalation flow in the three PCD subjects exposed twice. During day 7–21 the three PCD subjects exposed twice cleared 9 % with normal flow, probably representing predominantly alveolar clearance, compared to 19 % with slow inhalation flow, probably representing mainly small airway clearance. This study shows that despite ciliary dysfunction, clearance continues in the small airways beyond 24 h. There are apparently additional clearance mechanisms present in the small airways.

  11. Influence of predator mutual interference and prey refuge on Lotka-Volterra predator-prey dynamics

    Science.gov (United States)

    Chen, Liujuan; Chen, Fengde; Wang, Yiqin

    2013-11-01

    A Lotka-Volterra predator-prey model incorporating a constant number of prey using refuges and mutual interference for predator species is presented. By applying the divergency criterion and theories on exceptional directions and normal sectors, we show that the interior equilibrium is always globally asymptotically stable and two boundary equilibria are both saddle points. Our results indicate that prey refuge has no influence on the coexistence of predator and prey species of the considered model under the effects of mutual interference for predator species, which differently from the conclusion without predator mutual interference, thus improving some known ones. Numerical simulations are performed to illustrate the validity of our results.

  12. The functional response of a generalist predator.

    Directory of Open Access Journals (Sweden)

    Sophie Smout

    Full Text Available BACKGROUND: Predators can have profound impacts on the dynamics of their prey that depend on how predator consumption is affected by prey density (the predator's functional response. Consumption by a generalist predator is expected to depend on the densities of all its major prey species (its multispecies functional response, or MSFR, but most studies of generalists have focussed on their functional response to only one prey species. METHODOLOGY AND PRINCIPAL FINDINGS: Using Bayesian methods, we fit an MSFR to field data from an avian predator (the hen harrier Circus cyaneus feeding on three different prey species. We use a simple graphical approach to show that ignoring the effects of alternative prey can give a misleading impression of the predator's effect on the prey of interest. For example, in our system, a "predator pit" for one prey species only occurs when the availability of other prey species is low. CONCLUSIONS AND SIGNIFICANCE: The Bayesian approach is effective in fitting the MSFR model to field data. It allows flexibility in modelling over-dispersion, incorporates additional biological information into the parameter priors, and generates estimates of uncertainty in the model's predictions. These features of robustness and data efficiency make our approach ideal for the study of long-lived predators, for which data may be sparse and management/conservation priorities pressing.

  13. Predator-prey size interaction in tropical ponds

    OpenAIRE

    Claude Gascon

    1989-01-01

    An experiment was set-up to see in mortality inflicted by tadpole predators depends on prey and predator sizes. Fish and dragonfly larvae were used as predators and two size classes of Osteocephalus taurinus tadpoles as prey. Results show that the effect of predators is dependent on the size structure of the prey population. Furthermore, dragonfly larvae are more voracious predators than the fish used in the experiment. Both predators occur in natural ponds where Osteocephalus taurinus lays i...

  14. Do predators influence the behaviour of bats?

    Science.gov (United States)

    Lima, Steven L; O'Keefe, Joy M

    2013-08-01

    Many aspects of animal behaviour are affected by real-time changes in the risk of predation. This conclusion holds for virtually all taxa and ecological systems studied, but does it hold for bats? Bats are poorly represented in the literature on anti-predator behaviour, which may reflect a lack of nocturnal predators specialized on bats. If bats actually experience a world with minimal anti-predator concerns, then they will provide a unique contrast within the realm of vertebrate ecology. Alternatively, such predator-driven behaviour in bats may not yet be fully understood, given the difficulties in working with these highly mobile and nocturnal animals. We provide a wide-ranging exploration of these issues in bat behaviour. We first cover the basic predator-prey information available on bats, both on potential predators and the ways in which bats might perceive predators and respond to attacks. We then cover work relevant to key aspects of bat behaviour, such as choice of daytime roosts, the nature of sleep and torpor, evening roost departures, moonlight avoidance, landscape-related movement patterns, and habitat selection. Overall, the evidence in favour of a strong influence of predators on bat behaviour is equivocal, with the picture clouded by contradictory results and a lack of information on potential predators and the perception of risk by bats. It seems clear that day-active bats run a considerable risk of being killed by diurnal raptors, which are able to capture bats with relative ease. Thus, bats taking advantage of a pulse of insects just prior to sunset are likely taking risks to gain much-needed energy. Further, the choice of daytime roosts by bats is probably strongly influenced by roost safety. Few studies, however, have directly addressed either of these topics. As a group, insectivorous temperate-zone bats show no clear tendency to avoid apparently risky situations, such as activity on moonlit nights. However, some observations are consistent

  15. Predation on dormice in Italy

    Directory of Open Access Journals (Sweden)

    Dino Scaravelli

    1995-05-01

    Full Text Available Abstract The authors analyse available data on the impact of predators on Dormouse populations in Italy. Dormice are found in the diet of 2 snakes (Vipera berus and V. aspis, 2 diurnal birds of prey (Buteo buteo and Aquila chrysaetos, 6 owls (Tyto alba, Strix aluco, Asio otus, Athene noctua, Bubo bubo and Glaucidium passerinum and 9 mammals (Rattus rattus, Ursus arctos, Canis lupus, Vulpes vulpes, Martes martes, M. foina, Meles meles, Felis silvestris and Sus scrofa in a variable percentage of the prey taken. Only Dryomys nitedula was never encountered as a prey item. The most common prey is Muscardinus avellanarius. There are significative regional differences in predation between bioclimatic areas of the Italian peninsula. The contribution of studies on predation to knowledge of Myoxid distribution is discussed. Riassunto Predazione di Mioxidi in Italia - Sono analizzati i dati pubblicati sull'impatto dei predatori sulle popolazioni di Myoxidae in Italia. Myoxidae sono stati riscontrati nelle diete di 2 serpenti (Vipera berus e V. aspis, 2 rapaci diurni (Buteo buteo e Aquila chrysaetos, 6 notturni (Tyto alba, Strix aluco, Asio otus, Athene noctua, Bubo bubo e Glaucidium passerinum e 9 mammiferi (Rattus rattus, Ursus arctos, Canis lupus, Vulpes vulpes, Martes martes, M foina, Meles meles, Felis silvestris e Sus scrofa in percentuale variabile nella comunità di prede. Solo Dryomys nitedula non è mai stato incontrato come preda. La specie piu comunemente predata risulta Muscardinus avellanarius. Sono discusse le

  16. Asymmetric wavefront aberrations and pupillary shapes induced by electrical stimulation of ciliary nerve in cats measured with compact wavefront aberrometer.

    Directory of Open Access Journals (Sweden)

    Suguru Miyagawa

    Full Text Available To investigate the changes in the wavefront aberrations and pupillary shape in response to electrical stimulation of the branches of the ciliary nerves in cats. Seven eyes of seven cats were studied under general anesthesia. Trains of monophasic pulses (current, 0.1 to 1.0 mA; duration, 0.5 ms/phase; frequency, 5 to 40 Hz were applied to the lateral or medial branch of the short ciliary nerve near the posterior pole of the eye. A pair of electrodes was hooked onto one or both branch of the short ciliary nerve. The electrodes were placed about 5 mm from the scleral surface. The wavefront aberrations were recorded continuously for 2 seconds before, 8 seconds during, and for 20 seconds after the electrical stimulation. The pupillary images were simultaneously recorded during the stimulation period. Both the wavefront aberrations and the pupillary images were obtained 10 times/sec with a custom-built wavefront aberrometer. The maximum accommodative amplitude was 1.19 diopters (D produced by electrical stimulation of the short ciliary nerves. The latency of the accommodative changes was very short, and the accommodative level gradually increased up to 4 seconds and reached a plateau. When only one branch of the ciliary nerve was stimulated, the pupil dilated asymmetrically, and the oblique astigmatism and one of the asymmetrical wavefront terms was also altered. Our results showed that the wavefront aberrations and pupillary dilations can be measured simultaneously and serially with a compact wavefront aberrometer. The asymmetric pupil dilation and asymmetric changes of the wavefront aberrations suggest that each branch of the ciliary nerve innervates specific segments of the ciliary muscle and dilator muscle of the pupil.

  17. Kill fore being killed: an experimental approach supports the predator-removal hypothesis as a determinant of intraguild predation in top predators

    OpenAIRE

    Rabaça, J.E.; Lourenço, Rui; Penteriani, Vincenzo; Delgado, Maria del Mar; Marchi-Bartolozzi, Michela

    2011-01-01

    Intraguild predation (IGP) has been explained in terms of competitor-removal, food-stress and predator removal hypotheses. Only the first two hypotheses have been fairly well studied. To test the predator-removal hypothesis as a force determining IGP in avian predators, we performed a field experiment to simulate the presence of an IG predator (eagle owl Bubo bubo dummy) in the surrounding of the nests of four potential IG prey (black kite Milvus migrans, red kite Milvus milvus, boot...

  18. Low-Reynolds-number predator

    Science.gov (United States)

    Ebrahimian, Mehran; Yekehzare, Mohammad; Ejtehadi, Mohammad Reza

    2015-12-01

    To generalize simple bead-linker model of swimmers to higher dimensions and to demonstrate the chemotaxis ability of such swimmers, here we introduce a low-Reynolds predator, using a two-dimensional triangular bead-spring model. Two-state linkers as mechanochemical enzymes expand as a result of interaction with particular activator substances in the environment, causing the whole body to translate and rotate. The concentration of the chemical stimulator controls expansion versus the contraction rate of each arm and so affects the ability of the body for diffusive movements; also the variation of activator substance's concentration in the environment breaks the symmetry of linkers' preferred state, resulting in the drift of the random walker along the gradient of the density of activators. External food or danger sources may attract or repel the body by producing or consuming the chemical activators of the organism's enzymes, inducing chemotaxis behavior. Generalization of the model to three dimensions is straightforward.

  19. Effects of Predation by Protists on Prokaryotic Community Function, Structure, and Diversity in Anaerobic Granular Sludge

    Science.gov (United States)

    Hirakata, Yuga; Oshiki, Mamoru; Kuroda, Kyohei; Hatamoto, Masashi; Kubota, Kengo; Yamaguchi, Takashi; Harada, Hideki; Araki, Nobuo

    2016-01-01

    Predation by protists is top-down pressure that regulates prokaryotic abundance, community function, structure, and diversity in natural and artificial ecosystems. Although the effects of predation by protists have been studied in aerobic ecosystems, they are poorly understood in anoxic environments. We herein studied the influence of predation by Metopus and Caenomorpha ciliates—ciliates frequently found in anoxic ecosystems—on prokaryotic community function, structure, and diversity. Metopus and Caenomorpha ciliates were cocultivated with prokaryotic assemblages (i.e., anaerobic granular sludge) in an up-flow anaerobic sludge blanket (UASB) reactor for 171 d. Predation by these ciliates increased the methanogenic activities of granular sludge, which constituted 155% of those found in a UASB reactor without the ciliates (i.e., control reactor). Sequencing of 16S rRNA gene amplicons using Illumina MiSeq revealed that the prokaryotic community in the UASB reactor with the ciliates was more diverse than that in the control reactor; 2,885–3,190 and 2,387–2,426 operational taxonomic units (>97% sequence similarities), respectively. The effects of predation by protists in anaerobic engineered systems have mostly been overlooked, and our results show that the influence of predation by protists needs to be examined and considered in the future for a better understanding of prokaryotic community structure and function. PMID:27431197

  20. Wolbachia infections in mosquitoes and their predators inhabiting rice field communities in Thailand and China.

    Science.gov (United States)

    Wiwatanaratanabutr, Itsanun; Zhang, Chongxing

    2016-07-01

    Wolbachia are inherited, endocytoplasmic bacteria that infect a wide range of arthropods. Here is the first systematic report on the study of Wolbachia infection in mosquitoes and their predators from both Thailand and China. In Thailand, 632 mosquito specimens (20 spp.) and 424 insect predators (23 spp.) were collected from the rice agroecosystem, mostly from the Central region, followed by the Northeast, the North and the South and were inhabiting rice fields, wetlands and ditches. In China, 928 mosquitoes (15 spp.) and 149 insect predators (16 spp.) were collected from rice fields along the Weishan Lake in Shandong province. Specimens were classified in the orders Diptera, Coleoptera, Odonata and Hemiptera. Using wsp, ftsZ, 16S rRNA and groE gene amplifications, Wolbachia were detected in 12 mosquito spp. and 6 predator spp. from Thailand and 11 mosquito spp. and 5 predator spp. from China. The relative Wolbachia densities of these species were determined using quantitative real-time PCR. The mosquito, Aedes albopictus, and the predator, Agriocnemis femina, had the highest bacterial densities. These results imply that Wolbachia of supergroup B are distributed throughout these insects, probably via horizontal transmission in rice agroecosystems. PMID:27012719

  1. Conjugation is necessary for a bacterial plasmid to survive under protozoan predation.

    Science.gov (United States)

    Cairns, Johannes; Jalasvuori, Matti; Ojala, Ville; Brockhurst, Michael; Hiltunen, Teppo

    2016-02-01

    Horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. Interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. Here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid RP4 in populations of the opportunist bacterial pathogen Serratia marcescens. A conjugation-defective mutant plasmid was unable to survive under predation, suggesting that conjugative transfer is required for plasmid persistence under the realistic condition of predation. These results indicate that multi-trophic interactions can affect the maintenance of conjugative plasmids with implications for bacterial evolution and the spread of antibiotic resistance genes. PMID:26843557

  2. Behavioral responses of native prey to disparate predators: naiveté and predator recognition.

    Science.gov (United States)

    Anson, Jennifer R; Dickman, Chris R

    2013-02-01

    It is widely accepted that predator recognition and avoidance are important behaviors in allowing prey to mitigate the impacts of their predators. However, while prey species generally develop anti-predator behaviors through coevolution with predators, they sometimes show accelerated adoption of these behaviors under strong selection pressure from novel species. We used a field manipulation experiment to gauge the ability of the common ringtail possum (Pseudocheirus peregrinus), a semi-arboreal Australian marsupial, to recognize and respond to olfactory cues of different predator archetypes. We predicted that ringtails would display stronger anti-predator behaviors to cues of the invasive European red fox (Vulpes vulpes) in areas where fox impacts had been greatest, and to cues of the native lace monitor (Varanus varius) in areas of sympatry compared with allopatry. We found that ringtails fled quickly and were more alert when exposed to the fecal odors of both predators compared to neutral and pungent control odors, confirming that predator odors are recognized and avoided. However, these aversive responses were similar irrespective of predator presence or level of impact. These results suggest that selection pressure from the fox has been sufficient for ringtails to develop anti-predator behaviors over the few generations since foxes have become established. In contrast, we speculate that aversive responses by ringtails to the lace monitor in areas where this predator is absent reflect recent coexistence of the two species. We conclude that rapid evolution of anti-predator behaviors may occur when selection is strong. The maintenance of these behaviors should allow re-establishment of predator-prey relationships if the interactants regain sympatry via range shifts or management actions to reintroduce them to their former ranges. PMID:22865005

  3. Bald eagle predation on common loon egg

    Science.gov (United States)

    DeStefano, Stephen; McCarthy, Kyle P.; Laskowski, Tom

    2010-01-01

    The Common Loon (Gavia immer) must defend against many potential egg predators during incubation, including corvids, Herring Gulls (Larus argentatus), raccoons (Procyon lotor), striped skunk (Mephitis mephitis), fisher (Martes pennanti), and mink (Neovison vison) (McIntyre 1988, Evers 2004, McCann et al. 2005). Bald Eagles (Haliaeetus leucocephalus) have been documented as predators of both adult Common Loons and their chicks (Vliestra and Paruk 1997, Paruk et al. 1999, Erlandson et al. 2007, Piper et al. 2008). In Wisconsin, where nesting Bald Eagles are abundant (.1200 nesting pairs, .1 young/pair/year), field biologists observed four instances of eagle predation of eggs in loon nests during the period 2002–2004 (M. Meyer pers. comm.). In addition, four cases of eagle predation of incubating adult loons were inferred from evidence found at the loon nest (dozens of plucked adult loon feathers, no carcass remains) and/or loon leg, neck, and skull bones beneath two active eagle nests, including leg bones containing the bands of the nearby (,25 m) incubating adult loon. However, although loon egg predation has been associated with Bald Eagles, predation events have yet to be described in peer-reviewed literature. Here we describe a photographic observation of predation on a Common Loon egg by an immature Bald Eagle as captured by a nest surveillance video camera on Lake Umbagog, a large lake (32 km2) at Umbagog National Wildlife Refuge (UNWR) in Maine.

  4. Management of Large Predators in Alaska

    Directory of Open Access Journals (Sweden)

    Boertje, R.D.

    2005-06-01

    Full Text Available Populations of wolves (Canis lupus, brown bears (Ursus arctos, and black bears (Ursus americanus in Alaska are abundant and highly productive. Their long-term future is secure due to abundant habitat and good wildlife management practices. In many areas of Alaska hunting and trapping regulates wolf numbers and keep them "in balance" with moose populations. However, high predation rates by wolves can severely depress prey populations and then hold them at a very low density many years. This is often referred to as a predator pit. Several moose populations in interior Alaska are in predator pits. In some of these areas, high densities of black and brown bears complicate the situation. Bears generally prey on moose calves for only a few weeks after they are born, but in some areas they kill up to 65% of the calves produced. Moose populations faced with high levels of predation by both wolves and bears will not recover without special management actions to reduce the predation rate. Efforts to regulate predator populations outside of normal hunting and trapping seasons are highly controversial. Many people are very strongly opposed to reducing wolf or bear populations to increase moose populations and provide for a higher harvest by humans. Other people that depend on the moose for food and/or recreation strongly support predator management. It is a clash of values that is generates great controversy in Alaska. We provide a brief history of the controversy over predator management in Alaska and make recommendations on how to manage large predators in Alaska.

  5. Modeling the Dynamics of Cooperative Predators

    OpenAIRE

    Lannsjö, Fredrik; Nurweze, Lionel; Sörensen, Kristina

    2012-01-01

    The focus of this thesis is the modeling of cooperative predators hunting ocks of animals. The modeling is based on biological studies of the behavior of speci c predators and their preys, lions and zebras for this case. General rules are established in order to model the overall hunting and escape strategies, with a focus on the former. The dynamics of the predator during the hunt are modeled using the unicycle model applied locally, i.e., applied to each agent. The cooperation is taken into...

  6. Both ciliary and non-ciliary functions of Foxj1a confer Wnt/β-catenin signaling in zebrafish left-right patterning

    Directory of Open Access Journals (Sweden)

    Ping Zhu

    2015-11-01

    Full Text Available The Wnt/β-catenin pathway is implicated in left-right (LR axis determination; however, the underlying mechanism remains elusive. Prompted by our recent discovery that Wnt signaling regulates ciliogenesis in the zebrafish Kupffer's vesicle (KV via Foxj1a, a ciliogenic transcription factor, we decided to elucidate functions of Foxj1a in Wnt-regulated LR pattern formation. We showed that targeted injection of wnt8a mRNA into a single cell at the 128-cell stage is sufficient to induce ectopic foxj1a expression and ectopic cilia. By interrogating the transcription circuit of foxj1a regulation, we found that both Lef1 and Tcf7 bind to a consensus element in the foxj1a promoter region. Depletion of Lef1 and Tcf7 inhibits foxj1a transcription in the dorsal forerunner cells, downregulates cilia length and number in KV, and randomizes LR asymmetry. Targeted overexpression of a constitutively active form of Lef1 also induced an ectopic protrusion that contains ectopic transcripts for sox17, foxj1a, and charon, and ectopic monocilia. Further genetic studies using this ectopic expression platform revealed two distinct functions of Foxj1a; mediating Wnt-governed monocilia length elongation as well as charon transcription. The novel Foxj1a-charon regulation is conserved in KV, and importantly, it is independent of the canonical role of Foxj1a in the biosynthesis of motile cilia. Together with the known function of motile cilia movement in generating asymmetric expression of charon, our data put forward a hypothesis that Foxj1a confers both ciliary and non-ciliary functions of Wnt signaling, which converge on charon to regulate LR pattern formation.

  7. Both ciliary and non-ciliary functions of Foxj1a confer Wnt/β-catenin signaling in zebrafish left-right patterning.

    Science.gov (United States)

    Zhu, Ping; Xu, Xiaolei; Lin, Xueying

    2015-01-01

    The Wnt/β-catenin pathway is implicated in left-right (LR) axis determination; however, the underlying mechanism remains elusive. Prompted by our recent discovery that Wnt signaling regulates ciliogenesis in the zebrafish Kupffer's vesicle (KV) via Foxj1a, a ciliogenic transcription factor, we decided to elucidate functions of Foxj1a in Wnt-regulated LR pattern formation. We showed that targeted injection of wnt8a mRNA into a single cell at the 128-cell stage is sufficient to induce ectopic foxj1a expression and ectopic cilia. By interrogating the transcription circuit of foxj1a regulation, we found that both Lef1 and Tcf7 bind to a consensus element in the foxj1a promoter region. Depletion of Lef1 and Tcf7 inhibits foxj1a transcription in the dorsal forerunner cells, downregulates cilia length and number in KV, and randomizes LR asymmetry. Targeted overexpression of a constitutively active form of Lef1 also induced an ectopic protrusion that contains ectopic transcripts for sox17, foxj1a, and charon, and ectopic monocilia. Further genetic studies using this ectopic expression platform revealed two distinct functions of Foxj1a; mediating Wnt-governed monocilia length elongation as well as charon transcription. The novel Foxj1a-charon regulation is conserved in KV, and importantly, it is independent of the canonical role of Foxj1a in the biosynthesis of motile cilia. Together with the known function of motile cilia movement in generating asymmetric expression of charon, our data put forward a hypothesis that Foxj1a confers both ciliary and non-ciliary functions of Wnt signaling, which converge on charon to regulate LR pattern formation. PMID:26432885

  8. Innate Predator Odor Aversion Driven by Parallel Olfactory Subsystems that Converge in the Ventromedial Hypothalamus.

    Science.gov (United States)

    Pérez-Gómez, Anabel; Bleymehl, Katherin; Stein, Benjamin; Pyrski, Martina; Birnbaumer, Lutz; Munger, Steven D; Leinders-Zufall, Trese; Zufall, Frank; Chamero, Pablo

    2015-05-18

    The existence of innate predator aversion evoked by predator-derived chemostimuli called kairomones offers a strong selective advantage for potential prey animals. However, it is unclear how chemically diverse kairomones can elicit similar avoidance behaviors. Using a combination of behavioral analyses and single-cell Ca(2+) imaging in wild-type and gene-targeted mice, we show that innate predator-evoked avoidance is driven by parallel, non-redundant processing of volatile and nonvolatile kairomones through the activation of multiple olfactory subsystems including the Grueneberg ganglion, the vomeronasal organ, and chemosensory neurons within the main olfactory epithelium. Perturbation of chemosensory responses in specific subsystems through disruption of genes encoding key sensory transduction proteins (Cnga3, Gnao1) or by surgical axotomy abolished avoidance behaviors and/or cellular Ca(2+) responses to different predator odors. Stimulation of these different subsystems resulted in the activation of widely distributed target regions in the olfactory bulb, as assessed by c-Fos expression. However, in each case, this c-Fos increase was observed within the same subnuclei of the medial amygdala and ventromedial hypothalamus, regions implicated in fear, anxiety, and defensive behaviors. Thus, the mammalian olfactory system has evolved multiple, parallel mechanisms for kairomone detection that converge in the brain to facilitate a common behavioral response. Our findings provide significant insights into the genetic substrates and circuit logic of predator-driven innate aversion and may serve as a valuable model for studying instinctive fear and human emotional and panic disorders. PMID:25936549

  9. The influence of generalist predators in spatially extended predator-prey systems

    DEFF Research Database (Denmark)

    Chakraborty, Subhendu

    2015-01-01

    involved in intraguild predation, i.e., the source of the additional food of the predator coincides with the food source of the prey population and thus both prey and predator populations compete for the same resource. The conditions for linear stability and Turing instability are analyzed for both the...... cases. In the presence of generalist predators, the system shows different pattern formations and spatiotemporal chaos which has important implications for ecosystem functioning not only in terms of their predictability, but also in influencing species persistence and ecosystem stability in response to......The presence of generalist predators is known to have important ecological impacts in several fields. They have wide applicability in the field of biological control. However, their role in the spatial distribution of predator and prey populations is still not clear. In this paper, the spatial...

  10. Effects of Additional Foods to Predators on Nutrient-Consumer-Predator Food Chain Model

    OpenAIRE

    Banshidhar Sahoo

    2012-01-01

    We have proposed a nutrient-consumer-predator model with additional food to predator, at variable nutrient enrichment levels. The boundedness property and the conditions for local stability of boundary and interior equilibrium points of the system are derived. Bifurcation analysis is done with respect to quality and quantity of additional food and consumer’s death rate for the model. The system has stable as well as unstable dynamics depending on supply of additional food to predator. This mo...

  11. Apex Predators Program Age and Growth Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Apex Predators Program staff have collected vertebral centra from sportfishing tournaments, cruises, commercial fishermen and strandings in the Northeast US since...

  12. Apex Predators Program Sportfishing Tournament Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Apex Predators Program staff have collected shark sportfishing tournamant data from the Northeast US since the 1960's. These tournaments offer a unique opportunity...

  13. Predator-dependent species-area relationships.

    Science.gov (United States)

    Ryberg, Wade A; Chase, Jonathan M

    2007-10-01

    In addition to having a positive effect on species richness (species-area relationships [SARs]), habitat area can influence the presence of predators, which can indirectly influence prey richness. While these direct and indirect effects of area on richness occur simultaneously, no research has examined how predation might contribute to SAR variation. We extend MacArthur and Wilson's equilibrium theory of island biogeography by including predation-induced shifts in prey extinction and predict that predators will reduce slopes of prey SARs. We provide support for this with data from two insular ecosystems: orthopteran richness in Ozark glades (rocky herbaceous communities within a forested matrix) with and without insectivorous lizards and zooplankton richness in freshwater ponds with and without zooplanktivorous fishes. Our results emphasize that anthropogenic activities yield simultaneous changes in processes altering diversity and that it is critical that we understand how these components of anthropogenic change interact to impact diversity. PMID:17891741

  14. Predator trapping on Monte Vista NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This letter is summarizing the status of predator trapping on Monte Vista National Wildlife refuge in light of the referendum passes in the State of Colorado...

  15. Floral asymmetry and predation risk modify pollinator behavior, but only predation risk decreases plant fitness.

    Science.gov (United States)

    Antiqueira, Pablo Augusto Poleto; Romero, Gustavo Quevedo

    2016-06-01

    Although predators and floral herbivores can potentially decrease plant fitness by changing pollinator behaviors, studies comparing the strength of these factors as well as their additive and interactive effects on pollinator visitation and plant fitness have not been conducted. In this study, we manipulated the floral symmetry and predator presence (artificial crab spiders) on the flowers of the shrub Rubus rosifolius (Rosaceae) in a 2 × 2 factorial randomized block design. We found that asymmetry and predators decreased pollinator visitation (mainly hymenopterans), and overall these factors did not interact (additive effects). The effect of predation risk on pollinator avoidance behavior was 62 % higher than that of floral asymmetry. Furthermore, path analyses revealed that only predation risk cascaded down to plant fitness, and it significantly decreased fruit biomass by 33 % and seed number by 28 %. We also demonstrated that R. rosifolius fitness is indirectly affected by visiting and avoidance behaviors of pollinators. The strong avoidance behavioral response triggered by predation risk may be related to predator pressure upon flowers. Although floral asymmetry caused by herbivory can alter the quality of resources, it should not exert the same evolutionary pressure as that of predator-prey interactions. Our study highlights the importance of considering simultaneous forces, such as predation risk and floral asymmetry, as well as pollinator behavior when evaluating ecological processes involving mutualistic plant-pollinator systems. PMID:26861474

  16. Neuroblastoma cells contain a trophic factor sharing biological and molecular properties with ciliary neurotrophic factor.

    OpenAIRE

    Heymanns, J.; Unsicker, K

    1987-01-01

    Ciliary neurotrophic factor (CNTF) is a protein supporting the in vitro survival of a characteristic spectrum of embryonic chicken and rat peripheral neurons. High-speed supernatants of extracts from two neuroblastoma (NB) cell lines--the mouse C 1300 N2a and the human IMR 32--mimic the effects of CNTF on identical target neurons. Promotion of survival is dose-dependent with an ED50 of 80 micrograms (IMR 32) and 140 micrograms (C 1300 N2a) of protein per ml and saturable at plateau values for...

  17. Ciliary neurotrophic factor induces cholinergic differentiation of rat sympathetic neurons in culture

    OpenAIRE

    S. Saadat; Sendtner, Michael; H. Rohrer(Universität Mainz, Germany)

    1989-01-01

    Ciliary neurotrophic factor (CNTF) influences the levels of choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH) in cultures of dissociated sympathetic neurons from newborn rats. In the presence of CNTF both the total and specific activity of ChAT was increased 7 d after culture by 15- and 18-fold, respectively, as compared to cultures kept in the absence of CNTF. Between 3 and 21 d in culture in the presence of CNTF the total ChAT activity increased by a factor of greater than 100....

  18. Ciliary neurotrophic factor (CNTF) prevents the degeneration of motor neurons after axotomy

    OpenAIRE

    Sendtner, Michael; Kreutzberg, Georg W.; Thoenen, Hans

    2009-01-01

    The period of natural cell death in the development of rodent motor neurons is followed by a period of sensitivity to axonal injury1-3. In the rat this early postnatal period of vulnerability coincides with that of very low ciliary neurotrophic factor (CNTF) levels in the sciatic nerve before CNTF increases to the high, adult levels4. The developmental time course of CNTF expression, its regional tissue distribution and its cytosolic localization (as suggested by its primary structure)4*5 fav...

  19. The primary cilium as a cellular receiver: organizing ciliary GPCR signaling.

    Science.gov (United States)

    Hilgendorf, Keren I; Johnson, Carl T; Jackson, Peter K

    2016-04-01

    The primary cilium is an antenna-like cellular protrusion mediating sensory and neuroendocrine signaling. Its localization within tissue architecture and a growing list of cilia-localized receptors, in particular G-protein-coupled receptors, determine a host of crucial physiologies, which are disrupted in human ciliopathies. Here, we discuss recent advances in the identification and characterization of ciliary signaling components and pathways. Recent studies have highlighted the unique signaling environment of the primary cilium and we are just beginning to understand how this design allows for highly amplified and regulated signaling. PMID:26926036

  20. Changes in the number of chick ciliary ganglion neuron processes with time in cell culture

    OpenAIRE

    1987-01-01

    The purpose of this study was to describe the shape of chick ciliary ganglion neurons dissociated from embryonic day 8 or 9 ganglia and maintained in vitro. Most of the neurons were multipolar during the first three days after plating, with an average of 6.0 processes extending directly from the cell body. The neurons became unipolar with time. The remaining primary process accounted for greater than 90% of the total neuritic arbor. This striking change in morphology was not due to the select...

  1. Range contraction in large pelagic predators

    OpenAIRE

    Worm, Boris; Tittensor, Derek P.

    2011-01-01

    Large reductions in the abundance of exploited land predators have led to significant range contractions for those species. This pattern can be formalized as the range–abundance relationship, a general macroecological pattern that has important implications for the conservation of threatened species. Here we ask whether similar responses may have occurred in highly mobile pelagic predators, specifically 13 species of tuna and billfish. We analyzed two multidecadal global data sets on the spat...

  2. Intraguild Predation and Native Lady Beetle Decline

    OpenAIRE

    Gardiner, Mary M.; Matthew E O'Neal; Landis, Douglas A.

    2011-01-01

    Coccinellid communities across North America have experienced significant changes in recent decades, with declines in several native species reported. One potential mechanism for these declines is interference competition via intraguild predation; specifically, increased predation of native coccinellid eggs and larvae following the introduction of exotic coccinellids. Our previous studies have shown that agricultural fields in Michigan support a higher diversity and abundance of exotic coccin...

  3. Bat predation on nocturnally migrating birds

    OpenAIRE

    Ibáñez, Carlos; Juste, Javier; García-Mudarra, Juan L.; Agirre-Mendi, Pablo T.

    2001-01-01

    Bat predation on birds is a very rare phenomenon in nature. Most documented reports of bird-eating bats refer to tropical bats that occasionally capture resting birds. Millions of small birds concentrate and cross over the world's temperate regions during migration, mainly at night, but no nocturnal predators are known to benefit from this enormous food resource. An analysis of 14,000 fecal pellets of the greater noctule bat (Nyctalus lasiopterus) reveals that this...

  4. Anarchy and Autarky: Endogenous Predation as a Barrier to Trade

    OpenAIRE

    Anderson, James E.; Douglas Marcouiller, S.J.

    1997-01-01

    Market exchange is subject to an endogenously determined level of predation which impedes specialization and gains from trade. We construct a model in which utility-maximizing agents opt between careers in production and careers in predation. Three types of equilibria may emerge: autarky (with no predation and no defense), insecure exchange equilibria (with predation and defense), and secure exchange equilibria (in which defense completely deters predation). Trading equilibria, two-thirds of ...

  5. Correlated Noises in a Prey-Predator Ecosystem

    Institute of Scientific and Technical Information of China (English)

    ZHONG Wei-Rong; SHAO Yuan-Zhi; HE Zhen-Hui

    2006-01-01

    @@ We investigate a Volterra ecosystem driven by correlated noises. The fluctuation in the death rate of the predator induces an increase of population density of the predators. The fluctuation in the growth rate of the prey, however,leads the predators to decay. It is reported that the predators undergo sensitivity to a random environment,whereas the preys exhibit a surprising endurance to the same stochastic factor. The predators are of better stability under strong correlation of noises.

  6. Clinical value of measurement of pulmonary radioaerosol mucociliary clearance in the work up of primary ciliary dyskinesia

    DEFF Research Database (Denmark)

    Munkholm, Mathias; Nielsen, Kim Gjerum; Mortensen, Jann

    2015-01-01

    BACKGROUND: We aimed to evaluate and define the general clinical applicability and impact of pulmonary radioaerosol mucociliary clearance (PRMC) on the work up of patients suspected of having primary ciliary dyskinesia (PCD). In addition, we wanted to evaluate the accuracy of the reference values...... primarily to results from nasal ciliary function testing, to electron microscopic (EM) examination of the ultrastructure of the cilia, and to the final clinical diagnosis. RESULTS: Of the 239 patients, 27 ended up with a final clinical diagnosis of definitive PCD. No patients with a PRMC test that was...... from updated data....

  7. Diversity of protists and bacteria determines predation performance and stability.

    Science.gov (United States)

    Saleem, Muhammad; Fetzer, Ingo; Harms, Hauke; Chatzinotas, Antonis

    2013-10-01

    Predation influences prey diversity and productivity while it effectuates the flux and reallocation of organic nutrients into biomass at higher trophic levels. However, it is unknown how bacterivorous protists are influenced by the diversity of their bacterial prey. Using 456 microcosms, in which different bacterial mixtures with equal initial cell numbers were exposed to single or multiple predators (Tetrahymena sp., Poterioochromonas sp. and Acanthamoeba sp.), we showed that increasing prey richness enhanced production of single predators. The extent of the response depended, however, on predator identity. Bacterial prey richness had a stabilizing effect on predator performance in that it reduced variability in predator production. Further, prey richness tended to enhance predator evenness in the predation experiment including all three protists predators (multiple predation experiment). However, we also observed a negative relationship between prey richness and predator production in multiple predation experiments. Mathematical analysis of potential ecological mechanisms of positive predator diversity-functioning relationships revealed predator complementarity as a factor responsible for both enhanced predator production and prey reduction. We suggest that the diversity at both trophic levels interactively determines protistan performance and might have implications in microbial ecosystem processes and services. PMID:23765100

  8. Ciliary metachronal wave propagation on the compliant surface of Paramecium cells.

    Science.gov (United States)

    Narematsu, Naoki; Quek, Raymond; Chiam, Keng-Hwee; Iwadate, Yoshiaki

    2015-12-01

    Ciliary movements in protozoa exhibit metachronal wave-like coordination, in which a constant phase difference is maintained between adjacent cilia. It is at present generally thought that metachronal waves require hydrodynamic coupling between adjacent cilia and the extracellular fluid. To test this hypothesis, we aspirated a Paramecium cell using a micropipette which completely sealed the surface of the cell such that no fluid could pass through the micropipette. Thus, the anterior and the posterior regions of the cell were hydrodynamically decoupled. Nevertheless, we still observed that metachronal waves continued to propagate from the anterior to the posterior ends of the cell, suggesting that in addition to hydrodynamic coupling, there are other mechanisms that can also transmit the metachronal waves. Such transmission was also observed in computational modeling where the fluid was fully decoupled between two partitions of a beating ciliary array. We also imposed cyclic stretching on the surface of live Paramecium cells and found that metachronal waves persisted in the presence of cyclic stretching. This demonstrated that, in addition to hydrodynamic coupling, a compliant substrate can also play a critical role in mediating the propagation of metachronal waves. PMID:26616106

  9. The Role of Ion Channels to Regulate Airway Ciliary Beat Frequency During Allergic Inflammation.

    Science.gov (United States)

    Joskova, M; Sutovska, M; Durdik, P; Koniar, D; Hargas, L; Banovcin, P; Hrianka, M; Khazaei, V; Pappova, L; Franova, S

    2016-01-01

    Overproduction of mucus is a hallmark of asthma. The aim of this study was to identify potentially effective therapies for removing excess mucus. The role of voltage-gated (Kir 6.1, KCa 1.1) and store-operated ion channels (SOC, CRAC) in respiratory cilia, relating to the tracheal ciliary beat frequency (CBF), was compared under the physiological and allergic airway conditions. Ex vivo experiments were designed to test the local effects of Kir 6.1, KCa 1.1 and CRAC ion channel modulators in a concentration-dependent manner on the CBF. Cilia, obtained with the brushing method, were monitored by a high-speed video camera and analyzed with ciliary analysis software. In natural conditions, a Kir 6.1 opener accelerated CBF, while CRAC blocker slowed it in a concentration-dependent manner. In allergic inflammation, the effect of Kir 6.1 opener was insignificant, with a tendency to decrease CBF. A cilio-inhibitory effect of a CRAC blocker, while gently reduced by allergic inflammation, remained significant. A KCa 1.1 opener turned out to significantly enhance the CBF under the allergic OVA-sensitized conditions. We conclude that optimally attuned concentration of KCa 1.1 openers or special types of bimodal SOC channel blockers, potentially given by inhalation, might benefit asthma. PMID:27369295

  10. Ultrastructural pathology of primary ciliary dyskinesia: report about 125 cases in Germany

    Directory of Open Access Journals (Sweden)

    Theegarten Dirk

    2011-11-01

    Full Text Available Abstract Background Primary ciliary dyskinesia (PCD is a rare genetically induced disorder of cilia inducing mainly respiratory diseases. Transmission electron microscopy (TEM analysis of ciliary ultrastructure is classically used for diagnosis. We report our experience of TEM investigations in a large series of patients. Methods TEM analysis performed of 742 biopsies from patients with suspected PCD was reviewed retrospectively. Ultrastructural defects were analysized further in 125 cases with changes typical for PCD. Results In 18.1% of patients diagnosis of PCD was made because of morphological alterations, in 68.2% secondary changes were seen. In 13.7% material was not feasible for analysis. Mostly defects of dynein arms were detected in PCD (96.8%. In particular defects of the inner arms (51.2% and combined dynein defects (37.6% were found. Total loss of dynein arms was dominant. Only in 3.2% deficiencies of central structures were found alone. Associated situs inversus or dextracardia was reported clinically in 21.4%. Conclusions TEM analysis is possible in most patients and a useful tool for diagnosis of PCD. Functional and genetic analysis should be done additionally. Registers should be installed to collect all available informations and push further research.

  11. Primary ciliary dyskinesia: evaluation using cilia beat frequency assessment via spectral analysis of digital microscopy images

    Science.gov (United States)

    Kögler, João E.; Macchione, Mariangela; Shoemark, Amelia; Saldiva, Paulo H. N.; Rodrigues, Joaquim C.

    2011-01-01

    Ciliary beat frequency (CBF) measurements provide valuable information for diagnosing of primary ciliary dyskinesia (PCD). We developed a system for measuring CBF, used it in association with electron microscopy to diagnose PCD, and then analyzed characteristics of PCD patients.1 The CBF measurement system was based on power spectra measured through digital imaging. Twenty-four patients suspected of having PCD (age 1–19 yr) were selected from a group of 75 children and adolescents with pneumopathies of unknown causes. Ten healthy, nonsmoking volunteers (age ≥17 yr) served as a control group. Nasal brush samples were collected, and CBF and electron microscopy were performed. PCD was diagnosed in 12 patients: 5 had radial spoke defects, 3 showed absent central microtubule pairs with transposition, 2 had outer dynein arm defects, 1 had a shortened outer dynein arm, and 1 had a normal ultrastructure. Previous studies have reported that the most common cilia defects are in the dynein arm. As expected, the mean CBF was higher in the control group (P < 0.001) and patients with normal ultrastructure (P < 0.002), than in those diagnosed with cilia ultrastructural defects (i.e., PCD patients). An obstructive ventilatory pattern was observed in 70% of the PCD patients who underwent pulmonary function tests. All PCD patients presented bronchial wall thickening on chest computed tomography scans. The protocol and diagnostic techniques employed allowed us to diagnose PCD in 16% of patients in this study. PMID:21551013

  12. Posterior Ciliary Artery Occlusion Caused by Hyaluronic Acid Injections Into the Forehead

    Science.gov (United States)

    Hu, Xiu Zhuo; Hu, Jun Yan; Wu, Peng Sen; Yu, Sheng Bo; Kikkawa, Don O.; Lu, Wei

    2016-01-01

    Abstract Although cosmetic facial soft tissue fillers are generally safe and effective, improper injections can lead to devastating and irreversible consequences. We represent the first known case of posterior ciliary artery occlusion caused by hyaluronic acid. A 41-year-old female presented with right visual loss 7 hours after receiving cosmetic hyaluronic acid injections into her forehead. Examination revealed no light perception in the right eye and multiple dark ischemic area of injection over the forehead and nose. The right fundus revealed a pink retina with optic nerve edema. Fluorescein angiogram showed several filling defects in the choroidal circulation and late hyperfluorescence in the choroid. A right posterior ciliary artery occlusion and embolic occlusion of facial artery braches was diagnosed. With hyaluronidase injection, hyperbaric oxygen therapy, oral aspirin, oral acetazolamide and dexamethasone venotransfuse treatment, the patient's forehead and nasal skin improved and vision recovered to hand movements. With proper technique, vascular occlusion is rare following facial filler injection. Vision consequences can be severe if filler emboli enter the ocular circulation. Physicians should be aware of this potential side effect, recognize its presentation, and be knowledgeable of effective management. PMID:26986163

  13. Posterior Ciliary Artery Occlusion Caused by Hyaluronic Acid Injections Into the Forehead: A Case Report.

    Science.gov (United States)

    Hu, Xiu Zhuo; Hu, Jun Yan; Wu, Peng Sen; Yu, Sheng Bo; Kikkawa, Don O; Lu, Wei

    2016-03-01

    Although cosmetic facial soft tissue fillers are generally safe and effective, improper injections can lead to devastating and irreversible consequences. We represent the first known case of posterior ciliary artery occlusion caused by hyaluronic acid. A 41-year-old female presented with right visual loss 7 hours after receiving cosmetic hyaluronic acid injections into her forehead. Examination revealed no light perception in the right eye and multiple dark ischemic area of injection over the forehead and nose. The right fundus revealed a pink retina with optic nerve edema. Fluorescein angiogram showed several filling defects in the choroidal circulation and late hyperfluorescence in the choroid. A right posterior ciliary artery occlusion and embolic occlusion of facial artery braches was diagnosed. With hyaluronidase injection, hyperbaric oxygen therapy, oral aspirin, oral acetazolamide and dexamethasone venotransfuse treatment, the patient's forehead and nasal skin improved and vision recovered to hand movements. With proper technique, vascular occlusion is rare following facial filler injection. Vision consequences can be severe if filler emboli enter the ocular circulation. Physicians should be aware of this potential side effect, recognize its presentation, and be knowledgeable of effective management. PMID:26986163

  14. Effects of perfluorooctane sulfonate on tracheal ciliary beating frequency in mice

    International Nuclear Information System (INIS)

    Perfluorooctane sulfonate (PFOS) is one of the emerging persistent organic pollutants, ubiquitously found in the global environment, even in human serum. PFOS has been reported to perturb Ca2+ homeostasis in Paramecium, cardiomyocytes and neurons. Since ciliary beat frequency (CBF) in the trachea is known to be increased by cytoplasmic Ca2+ elevation, the effects of PFOS on CBF were evaluated in a slice preparation using video-enhanced contrast microscopy. PFOS increased CBF by 11% (P 2+ concentration ([Ca2+]i) in mouse tracheal ciliary cells. In Ca2+-free solution, PFOS at 100 μM failed to increase CBF (0.96-fold of vehicle control). The addition of Gd3+ (1 μM), a store-operated Ca2+ channel blocker, did not prevent the increase in CBF (1.09-fold (P + concentration (50 mM), which causes depolarization of the plasma membrane potential and a transient increase in [Ca2+]i, increased CBF by 20% (P 2+ channels (VDCCs) in stimulation of CBF. Nifedipine (30 μM), a selective VDCC blocker, antagonized the effects of high K+ (0.92-fold of high K+ solution) and PFOS (0.96-fold of vehicle control) on CBF. In cells from peroxisome proliferator-activated receptor α (PPARα)-null mice, PFOS still increased CBF (1.12-fold (P 2+ through VDCC

  15. Ciliary IFT80 balances canonical versus non-canonical hedgehog signalling for osteoblast differentiation

    Science.gov (United States)

    Yuan, Xue; Cao, Jay; He, Xiaoning; Serra, Rosa; Qu, Jun; Cao, Xu; Yang, Shuying

    2016-01-01

    Intraflagellar transport proteins (IFT) are required for hedgehog (Hh) signalling transduction that is essential for bone development, however, how IFT proteins regulate Hh signalling in osteoblasts (OBs) remains unclear. Here we show that deletion of ciliary IFT80 in OB precursor cells (OPC) in mice results in growth retardation and markedly decreased bone mass with impaired OB differentiation. Loss of IFT80 blocks canonical Hh–Gli signalling via disrupting Smo ciliary localization, but elevates non-canonical Hh–Gαi–RhoA–stress fibre signalling by increasing Smo and Gαi binding. Inhibition of RhoA and ROCK activity partially restores osteogenic differentiation of IFT80-deficient OPCs by inhibiting non-canonical Hh–RhoA–Cofilin/MLC2 signalling. Cytochalasin D, an actin destabilizer, dramatically restores OB differentiation of IFT80-deficient OPCs by disrupting actin stress fibres and promoting cilia formation and Hh–Gli signalling. These findings reveal that IFT80 is required for OB differentiation by balancing between canonical Hh–Gli and non-canonical Hh–Gαi–RhoA pathways and highlight IFT80 as a therapeutic target for craniofacial and skeletal abnormalities. PMID:26996322

  16. Measurement of ciliary beat frequency using ultra-high resolution optical coherence tomography

    Science.gov (United States)

    Chen, Jason J.; Jing, Joseph C.; Su, Erica; Badger, Christopher; Coughlan, Carolyn A.; Chen, Zhongping; Wong, Brian J. F.

    2016-02-01

    Ciliated epithelial cells populate up to 80% of the surface area of the human airway and are responsible for mucociliary transport, which is the key protective mechanism that provides the first line of defense in the respiratory tract. Cilia beat in a rhythmic pattern and may be easily affected by allergens, pollutants, and pathogens, altering ciliary beat frequency (CBF) subsequently. Diseases including cystic fibrosis, chronic obstructive pulmonary disease, and primary ciliary dyskinesia may also decrease CBF. CBF is therefore a critical component of respiratory health. The current clinical method of measuring CBF is phase-contrast microscopy, which involves a tissue biopsy obtained via brushing of the nasal cavity. While this method is minimally invasive, the tissue sample must be oriented to display its profile view, making the visualization of a single layer of cilia challenging. In addition, the conventional method requires subjective analysis of CBF, e.g., manually counting by visual inspection. On the contrary, optical coherence tomography (OCT) has been used to study the retina in ophthalmology as well as vasculature in cardiology, and offers higher resolution than conventional computed tomography and magnetic resonance imaging. Based on this technology, our lab specifically developed an ultra-high resolution OCT system to image the microstructure of the ciliated epithelial cells. Doppler analysis was also performed to determine CBF. Lastly, we also developed a program that utilizes fast Fourier transform to determine CBF under phase-contrast microscopy, providing a more objective method compared to the current method.

  17. Genotypic variation in response to salinity in a new sexual germplasm of Cenchrus ciliaris L.

    Science.gov (United States)

    Quiroga, Mariana; Tommasino, Exequiel; Griffa, Sabrina; Ribotta, Andrea; Colomba, Eliana López; Carloni, Edgardo; Grunberg, Karina

    2016-05-01

    As part of a breeding program for new salt-tolerant sexual genotypes of Cenchrus ciliaris L., here we evaluated the salt-stress response of two new sexual hybrids, obtained by controlled crosses, at seedling and germination stages. A seedling hydroponic experiment with 300 mM NaCl was performed and physiological variables and growth components were evaluated. While salt-treated sexual material did not show a decrease in productivity with respect to control plants, a differential response in some physiological characteristics was observed. Sexual hybrid 1-9-1 did not suffer oxidative damage and its proline content did not differ from that of control treatment. By contrast, sexual hybrid 1-7-11 suffered oxidative damage and accumulated proline, maintaining its growth under saline stress. At the germination stage, sexual hybrid 1-9-1 presented the highest Germination Rate Index at the maximum NaCl concentration assayed, suggesting an ecological advantage in this genotype. These new sexual resources are promising maternal parental with differential response to salt and could be incorporated in a breeding program of C. ciliaris in the search of new genotypes tolerant to salinity. PMID:26906150

  18. C2 Domains as Protein-Protein Interaction Modules in the Ciliary Transition Zone

    Directory of Open Access Journals (Sweden)

    Kim Remans

    2014-07-01

    Full Text Available RPGR-interacting protein 1 (RPGRIP1 is mutated in the eye disease Leber congenital amaurosis (LCA and its structural homolog, RPGRIP1-like (RPGRIP1L, is mutated in many different ciliopathies. Both are multidomain proteins that are predicted to interact with retinitis pigmentosa G-protein regulator (RPGR. RPGR is mutated in X-linked retinitis pigmentosa and is located in photoreceptors and primary cilia. We solved the crystal structure of the complex between the RPGR-interacting domain (RID of RPGRIP1 and RPGR and demonstrate that RPGRIP1L binds to RPGR similarly. RPGRIP1 binding to RPGR affects the interaction with PDEδ, the cargo shuttling factor for prenylated ciliary proteins. RPGRIP1-RID is a C2 domain with a canonical β sandwich structure that does not bind Ca2+ and/or phospholipids and thus constitutes a unique type of protein-protein interaction module. Judging from the large number of C2 domains in most of the ciliary transition zone proteins identified thus far, the structure presented here seems to constitute a cilia-specific module that is present in multiprotein transition zone complexes.

  19. Characterization of specific binding sites for PAF in the iris and ciliary body of rabbit

    International Nuclear Information System (INIS)

    The protective effect exerted by BN 52021 a specific PAF-receptor antagonist in experimentally induced ocular inflammatory disorders led us to investigate the possible presence of specific receptors for PAF in rabbit iris and ciliary body. Two classes of PAF binding sites were found in isolated iris and ciliary process of pigmented rabbit eyes: a high affinity site Kd1 congruent to 4.9 +/- 0.47 nM, Bmax1 congruent to 3.17 +/- 0.50 pmoles/mg protein, a low affinity sites Kd2 congruent to 11.6 +/- 0.33 nM, Bmax2 congruent to 12.46 +/- 2.3 pmoles/mg protein for iris. The specific binding was not affected by lyso-PAF the biologically inactive precursor and metabolite of PAF, up to 10(-6) M; inhibition by unlabelled PAF demonstrated a biphasic curve partially antagonized by BN 52021. The present results demonstrate the presence of specific binding sites for PAF in rabbit eyes which could mediate the action of this mediator in eye inflammatory processes and explain the protective effect observed with BN 52021

  20. Olfactory response of the predator Zetzellia mali to a prey patch occupied by a conspecific predator

    NARCIS (Netherlands)

    A. Zahedi-Golpayegani; A. Saboori; M.W. Sabelis

    2007-01-01

    While searching for food, predators may use volatiles associated with their prey, but also with their competitors for prey. This was tested for the case of Zetzellia mali (Ewing) (Acari: Stigmaeidae), an important predator of the hawthorn spider mite, Amphitetranychus viennensis (Zacher) (Acari: Tet

  1. Predator-induced changes in metabolism cannot explain the growth/predation risk tradeoff

    DEFF Research Database (Denmark)

    Steiner, Uli; Van Buskirk, Josh

    2009-01-01

    , consistent with the "fight-or-flight" response observed in many organisms. The long term reaction showed the opposite pattern: tadpoles reduced oxygen consumption after three weeks exposure to predators, which would act to reduce the growth cost of predator defence. The results point to an instantaneous and...

  2. Effects of a ciliate protozoa predator on microbial communities in pitcher plant (Sarracenia purpurea leaves.

    Directory of Open Access Journals (Sweden)

    Taylor K Paisie

    Full Text Available The aquatic communities found within the water filled leaves of the pitcher plant, Sarracenia purpurea, have a simple trophic structure providing an ideal system to study microscale interactions between protozoan predators and their bacterial prey. In this study, replicate communities were maintained with and without the presence of the bactivorous protozoan, Colpoda steinii, to determine the effects of grazing on microbial communities. Changes in microbial (Archaea and Bacteria community structure were assessed using iTag sequencing of 16S rRNA genes. The microbial communities were similar with and without the protozoan predator, with>1000 species. Of these species, Archaea were negligible, with Bacteria comprising 99.99% of the microbial community. The Proteobacteria and Bacteroidetes were the most dominant phyla. The addition of a protozoan predator did not have a significant effect on microbial evenness nor richness. However, the presence of the protozoan did cause a significant shift in the relative abundances of a number of bacterial species. This suggested that bactivorous protozoan may target specific bacterial species and/or that certain bacterial species have innate mechanisms by which they evade predators. These findings help to elucidate the effect that trophic structure perturbations have on predator prey interactions in microbial systems.

  3. Invasion and predation in aquatic ecosystems

    Institute of Scientific and Technical Information of China (English)

    Judith S. WEIS

    2011-01-01

    This article reviews biological invasions in which predation (or its absence) plays a major role in the success of the invader.Examples are described in which the invader out-competes native species for the same food,and cases in which the invader consumes valued native species.In many instances,better predator avoidance by the invasive species or the absence of predators in the new habitat contributes to the success of the invaders; in other cases native or introduced predators appear to be able to keep the invasive species in check.A relatively new management approach in the US is the idea of adding another trophic level-to have humans act as the predators and consume the invasive species.This approach is being utilized in Florida and throughout the Caribbean against the lionfish,but could be extended to other fishes,as well as to various invasive crustaceans and mollusks.This idea is controversial,and current regulations prohibiting the possession of individuals of the invasive species (e.g.,mitten crabs or snakefish) would preclude the development of a fishery for them [Current Zoology 57 (5):613-624,2011].

  4. Group formation stabilizes predator-prey dynamics.

    Science.gov (United States)

    Fryxell, John M; Mosser, Anna; Sinclair, Anthony R E; Packer, Craig

    2007-10-25

    Theoretical ecology is largely founded on the principle of mass action, in which uncoordinated populations of predators and prey move in a random and well-mixed fashion across a featureless landscape. The conceptual core of this body of theory is the functional response, predicting the rate of prey consumption by individual predators as a function of predator and/or prey densities. This assumption is seriously violated in many ecosystems in which predators and/or prey form social groups. Here we develop a new set of group-dependent functional responses to consider the ecological implications of sociality and apply the model to the Serengeti ecosystem. All of the prey species typically captured by Serengeti lions (Panthera leo) are gregarious, exhibiting nonlinear relationships between prey-group density and population density. The observed patterns of group formation profoundly reduce food intake rates below the levels expected under random mixing, having as strong an impact on intake rates as the seasonal migratory behaviour of the herbivores. A dynamical system model parameterized for the Serengeti ecosystem (using wildebeest (Connochaetes taurinus) as a well-studied example) shows that grouping strongly stabilizes interactions between lions and wildebeest. Our results suggest that social groups rather than individuals are the basic building blocks around which predator-prey interactions should be modelled and that group formation may provide the underlying stability of many ecosystems. PMID:17960242

  5. Regulation of protein phosphorylation of the intermediate-sized filament vimentin in the ciliary epithelium of the mammalian eye

    International Nuclear Information System (INIS)

    The intermediate-sized filaments of vimentin-type (Mr = 57,000) have been identified biochemically and immunochemically as a major cytoskeleton component in the ciliary epithelium of the mammalian eye. When human or rabbit ciliary processes, or cultured ciliary epithelial-derived cells were incubated in serum-free medium containing [32P]orthophosphate and any of the following agents: 1) beta-adrenergic agonists (isoproterenol or epinephrine), 2) direct activators of adenylate cyclase (cholera toxin or forskolin), 3) analogs of cyclic AMP (8-Br-cAMP), or 4) prostaglandin E1, the phosphorylation of vimentin was significantly enhanced. The maximal enhancement ranged, in vivo and in vitro, from about 3-fold in human to 5-fold in rabbit, with either 1 mM 8-Br-cAMP or 0.1 microM forskolin. Indirect immunofluorescence microscopy using a monoclonal antibody, anti-vimentin, allowed the localization of vimentin filaments in cultured ciliary epithelial cells. Treatment of these cells in culture with the catecholamine hormone, isoproterenol (1 microM), resulted in a profound reorganization of vimentin filaments. This may be correlated with the enhanced levels of phosphorylated vimentin observed upon increasing cellular cyclic AMP

  6. Codon optimization and factorial screening for enhanced soluble expression of human ciliary neurotrophic factor in Escherichia coli

    OpenAIRE

    Itkonen, Jaakko M; Urtti, Arto; Bird, Louise E.; Sarkhel, Sanjay

    2014-01-01

    Abstract Background Neurotrophic factors influence survival, differentiation, proliferation and death of neuronal cells within the central nervous system. Human ciliary neurotrophic factor (hCNTF) has neuroprotective properties and is also known to influence energy balance. Consequently, hCNTF has potential therapeutic applications in neurodegenerative, obesity and diabetes relat...

  7. A minimal model of predator-swarm interactions

    OpenAIRE

    Chen, Yuxin; Kolokolnikov, Theodore

    2014-01-01

    We propose a minimal model of predator–swarm interactions which captures many of the essential dynamics observed in nature. Different outcomes are observed depending on the predator strength. For a ‘weak’ predator, the swarm is able to escape the predator completely. As the strength is increased, the predator is able to catch up with the swarm as a whole, but the individual prey is able to escape by ‘confusing’ the predator: the prey forms a ring with the predator at the centre. For higher pr...

  8. Kill before being killed: An experimental approach supports the predator-removal hypothesis as a determinant of intraguild predation in top predators

    OpenAIRE

    Lourenço, Rui; Penteriani, Vincenzo; Delgado, María del Mar

    2011-01-01

    Intraguild predation (IGP) has been explained in terms of competitor-removal, food-stress and predator-removal hypotheses. Only the first two hypotheses have been fairly well studied. To test the predator-removal hypothesis as a force determining IGP in avian predators, we performed a field experiment to simulate the presence of an IG predator (eagle owl Bubo bubo dummy) in the surrounding of the nests of four potential IG prey (black kite Milvus migrans, red kite Milvus milvus, booted eagle ...

  9. Predators and the breeding bird: behavioral and reproductive flexibility under the risk of predation.

    Science.gov (United States)

    Lima, Steven L

    2009-08-01

    A growing body of work suggests that breeding birds have a significant capacity to assess and respond, over ecological time, to changes in the risk of predation to both themselves and their eggs or nestlings. This review investigates the nature of this flexibility in the face of predation from both behavioural and reproductive perspectives, and also explores several directions for future research. Most available work addresses different aspects of nest predation. A substantial change in breeding location is perhaps the best documented response to nest predation, but such changes are not always observed and not necessarily the best strategy. Changes in nesting microhabitat (to more concealed locations) following predation are known to occur. Surprisingly little work addresses the proactive avoidance of areas with many nest predators, but such avoidance is probably widespread. Individual birds could conceivably adopt anti-predator strategies based on the nest predators actually present in an area, but such effects have yet to be demonstrated. In fact, the ways in which birds assess the risk of nest predation is unclear. Nest defence in birds has historically received much attention, but little is known about how it interacts with other aspects of decision-making by parents. Other studies concentrate on predation risk to adults. Some findings suggest that risk to adults themselves influences territory location, especially relative to raptor nests. An almost completely unexplored area concerns the sorts of social protection from predators that might exist during the breeding season. Flocking typical of the non-breeding season appears unusual while breeding, but a mated pair may sometimes act as a "flock of two". Opportunistic heterospecific sociality may exist, with heterospecific protector species associations more prevalent than currently appreciated. The dynamics of singing during the breeding season may also respond to variation in predation risk, but empirical

  10. Ciliogenesis in Caenorhabditis elegans requires genetic interactions between ciliary middle segment localized NPHP-2 (inversin) and transition zone-associated proteins

    Science.gov (United States)

    Warburton-Pitt, Simon R. F.; Jauregui, Andrew R.; Li, Chunmei; Wang, Juan; Leroux, Michel R.; Barr, Maureen M.

    2012-01-01

    The cystic kidney diseases nephronophthisis (NPHP), Meckel–Gruber syndrome (MKS) and Joubert syndrome (JBTS) share an underlying etiology of dysfunctional cilia. Patients diagnosed with NPHP type II have mutations in the gene INVS (also known as NPHP2), which encodes inversin, a cilia localizing protein. Here, we show that the C. elegans inversin ortholog, NPHP-2, localizes to the middle segment of sensory cilia and that nphp-2 is partially redundant with nphp-1 and nphp-4 (orthologs of human NPHP1 and NPHP4, respectively) for cilia placement within the head and tail sensilla. nphp-2 also genetically interacts with MKS ciliopathy gene orthologs, including mks-1, mks-3, mks-6, mksr-1 and mksr-2, in a sensilla-dependent manner to control cilia formation and placement. However, nphp-2 is not required for correct localization of the NPHP- and MKS-encoded ciliary transition zone proteins or for intraflagellar transport (IFT). We conclude that INVS/NPHP2 is conserved in C. elegans and that nphp-2 plays an important role in C. elegans cilia by acting as a modifier of the NPHP and MKS pathways to control cilia formation and development. PMID:22393243

  11. Warming increases chlorpyrifos effects on predator but not anti-predator behaviours.

    Science.gov (United States)

    Dinh Van, Khuong; Janssens, Lizanne; Debecker, Sara; Stoks, Robby

    2014-07-01

    Recent insights indicate that negative effects of pesticides on aquatic biota occur at concentrations that current legislation considers environmentally protective. We here address two, potentially interacting, mechanisms that may contribute to the underestimation of the impact of sublethal pesticide effects in single species tests at room temperature: the impairment of predator and antipredator behaviours and the stronger impact of organophosphate pesticides at higher temperatures. To address these issues we assessed the effects of chlorpyrifos on the predator and antipredator behaviours of larvae of the damselfly Ischnura elegans, important intermediate predators in aquatic food webs, in a common-garden warming experiment with replicated low- and high-latitude populations along the latitudinal gradient of this species in Europe. Chlorpyrifos reduced the levels of predator behavioural endpoints, and this reduction was stronger at the higher temperature for head orientations and feeding strikes. Chlorpyrifos also impaired two key antipredator behavioural endpoints, activity reductions in response to predator cues were smaller in the presence of chlorpyrifos, and chlorpyrifos caused a lower escape swimming speed; these effects were independent of temperature. This suggests chlorpyrifos may impact food web interactions by changing predator-prey interactions both with higher (predators) and lower trophic levels (food). Given that only the interaction with the lower trophic level was more impaired at higher temperatures, the overall pesticide-induced changes in food web dynamics may be strongly temperature-dependent. These findings were consistent in damselflies from low- and high-latitude populations, illustrating that thermal adaptation will not mitigate the increased toxicity of pesticides at higher temperatures. Our study not only underscores the relevance of including temperature and prey-predator interactions in ecological risk assessment but also their potential

  12. Effects of spatial grouping on the functional response of predators

    Science.gov (United States)

    Cosner, C.; DeAngelis, D.L.; Ault, J.S.; Olson, D.B.

    1999-01-01

    A unified mechanistic approach is given for the derivation of various forms of functional response in predator-prey models. The derivation is based on the principle-of-mass action but with the crucial refinement that the nature of the spatial distribution of predators and/or opportunities for predation are taken into account in an implicit way. If the predators are assumed to have a homogeneous spatial distribution, then the derived functional response is prey-dependent. If the predators are assumed to form a dense colony or school in a single (possibly moving) location, or if the region where predators can encounter prey is assumed to be of limited size, then the functional response depends on both predator and prey densities in a manner that reflects feeding interference between predators. Depending on the specific assumptions, the resulting functional response may be of Beddington-DeAngelis type, of Hassell-Varley type, or ratio-dependent.

  13. Proton-beam irradiated epithelioid cell melanoma of the ciliary body

    International Nuclear Information System (INIS)

    A malignant ciliary body melanoma received proton-beam irradiation. After an apparent failure of the tumor to respond, the eye was enucleated. A predominantly epithelioid cell tumor appeared viable by light microscopy, and a low degree of mitotic activity persisted, despite therapy. The tumor cells, however, displayed degenerative changes ultrastructurally, presumably results of the radiotherapy. These consisted of numerous cytoskeletal filaments, lipid vacuoles, prominent phagolysosomes, and nuclear convolutions and fragmentations. The mitochondria were fewer in number in the present tumor than typically encountered in epithelioid cells. A rare leptomeric structure was discovered, probably an organizational modification of the cytoplasmic filaments. The tumor's capillaries showed radiation-induced changes in terms of thickened basement membranes and perivascular fibrin deposition. The foregoing features are indicative of cellular and metabolic injury from the radiotherapy, but these were evidently not sufficiently injurious to sterilize the tumor

  14. Choice of nasal nitric oxide technique as first-line test for primary ciliary dyskinesia

    DEFF Research Database (Denmark)

    Marthin, J K; Nielsen, K G

    2011-01-01

    Nasal nitric oxide (nNO) has a well-known potential as an indirect discriminative marker between patients with primary ciliary dyskinesia (PCD) and healthy subjects, but real-life experience and usefulness in young children is sparsely reported. Three nNO sampling methods were examined and compared...... as first-line tests for PCD. Healthy subjects, confirmed PCDs, consecutive referrals with PCD-like symptoms and patients with cystic fibrosis (CF) had nNO sampled during breath hold (BH-nNO), oral exhalation against resistance (OE-R-nNO) and tidal breathing (TB-nNO) aiming to expand age range into...... infancy. 282 subjects, 117 consecutive referrals, 59 PCDs, 49 CF patients and 57 healthy subjects, were included. All methods separated significantly between PCD and non-PCD, including CF with reliability, in ranking order BH-nNO>OE-R-nNO>TB-nNO. Acceptability in children ranked in reverse order. A...

  15. The isolated ciliary bilayer is useful for studies of aqueous humor formation.

    Science.gov (United States)

    Sears, M L; Yamada, E; Cummins, D; Mori, N; Mead, A; Murakami, M

    1991-01-01

    An intact ciliary epithelial bilayer has been isolated from the rabbit eye by perfusion, microsurgical dissection, and recovery techniques. Vital subcellular organelles and intercellular junctions of this epithelial bilayer preparation are very well preserved. The total electrical resistance of the epithelial bilayer is 350 ohms, and the transepithelial potential is 650 microV, nonpigmented epithelium side negative. The electrical resistance is reduced by 0.2 mM EGTA and the transepithelial potential reduced by 0.1 mM ouabain. Bicarbonate depletion at a constant pH of 7.4 rapidly and significantly reduces the transepithelial potential. Carbonic anhydrase inhibitors decrease transmembrane potential by as much as 30%. These morphologic and physiologic experiments authenticate the validity of this bilayered epithelial preparation for future use in detailed studies of the mechanism of aqueous humor formation. PMID:1808804

  16. Efficiency optimization and symmetry-breaking in a model of ciliary locomotion

    CERN Document Server

    Michelin, Sebastien

    2010-01-01

    A variety of swimming microorganisms, called ciliates, exploit the bending of a large number of small and densely-packed organelles, termed cilia, in order to propel themselves in a viscous fluid. We consider a spherical envelope model for such ciliary locomotion where the dynamics of the individual cilia are replaced by that of a continuous overlaying surface allowed to deform tangentially to itself. Employing a variational approach, we determine numerically the time-periodic deformation of such surface which leads to low-Reynolds locomotion with minimum rate of energy dissipation (maximum efficiency). Employing both Lagrangian and Eulerian points of views, we show that in the optimal swimming stroke, individual cilia display weak asymmetric beating, but that a significant symmetry-breaking occurs at the organism level, with the whole surface deforming in a wave-like fashion reminiscent of metachronal waves of biological cilia. This wave motion is analyzed using a formal modal decomposition, is found to occu...

  17. Habitat selection and consumption across a landscape of multiple predators

    OpenAIRE

    Wesner, Jeff S; Meyers, Peter; Eric J. Billman; Mark C Belk

    2014-01-01

    Predator community composition can alter habitat quality for prey by changing the strength and direction of consumptive effects. Whether predator community composition also alters prey density via nonconsumptive effects during habitat selection is not well known, but is important for understanding how changes to predator communities will alter prey populations. We tested the hypothesis that predator community composition (presence of caged trout, caged dragonflies, or caged trout + dragonflie...

  18. Effects of ouabain and furosemide on transepithelial electrical parameters of the isolated shark ciliary epithelium.

    Science.gov (United States)

    Wiederholt, M; Zadunaisky, J A

    1987-08-01

    Sections of the ciliary epithelium of adult sharks (Squalus acanthias) were mounted in Ussing-type chambers (area 0.2 cm2) for measurements of transepithelial potential difference (PD), short circuit current (SCC) and calculation of transepithelial resistance (R). In 15 preparations PD was aqueous side negative (-0.51 +/- 0.12 mV; SCC 18.3 +/- 2.5 microA cm-2; R 30.7 +/- 3.1 Ohm cm2). However, in 15 other preparations incubated in identical Ringer's solution PD was aqueous side positive (0.53 +/- 0.09 mV; SCC -19.6 +/- 2.3 microA cm-2; R 27.9 +/- 2.8 Ohm cm2). 10(-5) M ouabain or 10(-4) M furosemide were applied either to the aqueous or blood side of the isolated ciliary epithelium at transepithelial negative or positive PD. When the transepithelial PD was positive on the aqueous side ouabain decreased PD and SCC within 15 to 45 min. When the spontaneous PD was negative both PD and SCC decreased when ouabain was applied to the blood side. When the drug was given to the aqueous side a biphasic response (first stimulation, then inhibition) of PD and SCC was observed. Furosemide when given to the blood side (with aqueous side PD positive) or to the aqueous side (with aqueous side PD negative) decreased PD and SCC. However, a transient stimulation of both electrical parameters was observed when furosemide was applied to either the blood side (with aqueous side PD negative) or to the aqueous side (with aqueous side PD positive). The polarity and magnitude of PD and SCC probably depend on the relative activity of sodium and chloride pumps across the cell membranes of the non-pigmented and/or pigmented cell layer. However, additional transport mechanisms cannot be excluded. PMID:3038770

  19. Histamine Stimulates Ciliary Beat Frequency via the H2 Receptor in the Protochordate Botryllus schlosseri.

    Science.gov (United States)

    Cima, Francesca; Franchi, Nicola

    2016-05-01

    Histamine is a biogenic molecule that plays a role in many physiological pathways via binding to a specific receptor. Histaminergic receptors belong to the large family of seven-transmembrane α-helix domain receptors classified in mammals into four distinct classes: H1, H2, H3, and H4. Despite being widely studied in vertebrates, few data are available on the invertebrate receptors, with only predicted H1 and H2 sequences for nonchordate deuterostomes. Here, we report the first characterized transcript sequence for an H2 receptor from the colonial ascidian Botryllus schlosseri, describing the localization of both transcript and protein during blastogenic development through in situ hybridization and immunohistochemistry. Its phylogenetic relationships with deuterostome orthologous proteins are reported, its role in ciliary beat frequency (CBF) in cultured stigma cells of the branchial basket is outlined, and the effects of histamine and its receptor agonists and antagonists are analyzed. In the presence of increasing concentrations of histamine in the medium, CBF increases similarly to the selective H2 receptor agonist dimaprit. In contrast, ranitidine, which is an inhibitor of the H2 receptor, causes a significant inhibition of CBF, similar to that observed after preincubation with the specific anti-BsHRH2 or the anti-human HRH2 antibody. In cells bordering the branchial basket stigmata, both antibodies colocalize in the proximal region of the ciliary plasmalemma, and histamine is present inside vesicles of the apical region, thus supporting the hypothesis of a histamine-binding H2 receptor control of the pharyngeal mucociliary transport similar to that of the upper respiratory tract and middle ear in mammals. PMID:27139577

  20. Carbon fluxes to Antarctic top predators

    NARCIS (Netherlands)

    Franeker, van J.A.; Bathmann, U.V.; Mathot, S.

    1997-01-01

    The role of birds, seals and whales in the overall biological carbon fluxes of the Southern Ocean has been estimated based on census counts of top predator individuals in the region. Using standard routines for conversion to food consumption and respiration rates we demonstrate that at most 0.3-0.6%

  1. Sexually Violent Predators and Civil Commitment Laws

    Science.gov (United States)

    Beyer Kendall, Wanda D.; Cheung, Monit

    2004-01-01

    This article analyzes the civil commitment models for treating sexually violent predators (SVPs) and analyzes recent civil commitment laws. SVPs are commonly defined as sex offenders who are particularly predatory and repetitive in their sexually violent behavior. Data from policy literature, a survey to all states, and a review of law review…

  2. Distribution of mammalian predator in fragmented landscape

    Czech Academy of Sciences Publication Activity Database

    Koubová, M.; Svobodová, Jana; Kreisinger, Jakub; Šálek, Martin; Šálek, M.; Albrecht, Tomáš

    Prague : Czech University of Life Sciences, 2009. s. 185. ISBN 978-80-213-1961-5. [European Congress of Conservation Biology /2./. 01.09.2009-05.09.2009, Prague] Institutional research plan: CEZ:AV0Z60930519 Keywords : predation * Central Europe Subject RIV: EH - Ecology, Behaviour http://www.eccb2009.org/uploads/book_of_abstracts_errata.pdf

  3. Where to locate to escape predation?

    OpenAIRE

    Andreea Cosnita-Langlais

    2014-01-01

    We study the credibility of predation to deter entry in the linear Cournot shipping model of spatial competition with strategic location choice, both on the linear and circular markets. For a high enough discount factor, the monopoly is preserved, but the credibility of predatory conduct is lower on the circular than on the linear market.

  4. What regulates crab predation on mangrove propagules?

    Science.gov (United States)

    Van Nedervelde, Fleur; Cannicci, Stefano; Koedam, Nico; Bosire, Jared; Dahdouh-Guebas, Farid

    2015-02-01

    Crabs play a major role in some ecosystems. To increase our knowledge about the factors that influence crab predation on propagules in mangrove forests, we performed experiments in Gazi Bay, Kenya in July 2009. We tested whether: (1) crab density influences propagule predation rate; (2) crab size influences food competition and predation rate; (3) crabs depredate at different rates according to propagule and canopy cover species; (4) vegetation density is correlated with crab density; (5) food preferences of herbivorous crabs are determined by size, shape and nutritional value. We found that (1) propagule predation rate was positively correlated to crab density. (2) Crab competitive abilities were unrelated to their size. (3) Avicennia marina propagules were consumed more quickly than Ceriops tagal except under C. tagal canopies. (4) Crab density was negatively correlated with the density of A. marina trees and pneumatophores. (5) Crabs prefer small items with a lower C:N ratio. Vegetation density influences crab density, and crab density affects propagule availability and hence vegetation recruitment rate. Consequently, the mutual relationships between vegetation and crab populations could be important for forest restoration success and management.

  5. Dynamics of a Diffusive Predator-Prey Model with Allee Effect on Predator

    Directory of Open Access Journals (Sweden)

    Xiaoqin Wang

    2013-01-01

    Full Text Available The reaction-diffusion Holling-Tanner prey-predator model considering the Allee effect on predator, under zero-flux boundary conditions, is discussed. Some properties of the solutions, such as dissipation and persistence, are obtained. Local and global stability of the positive equilibrium and Turing instability are studied. With the help of the numerical simulations, the rich Turing patterns, including holes, stripes, and spots patterns, are obtained.

  6. Unidirectional prey–predator facilitation: apparent prey enhance predators' foraging success on cryptic prey

    OpenAIRE

    Zhang, Yixin; Richardson, John S

    2007-01-01

    Food availability can strongly affect predator–prey dynamics. When change in habitat condition reduces the availability of one prey type, predators often search for other prey, perhaps in a different habitat. Interactions between behavioural and morphological traits of different prey may influence foraging success of visual predators through trait-mediated indirect interactions (TMIIs), such as prey activity and body coloration. We tested the hypothesis that foraging success of stream-dwellin...

  7. Predation of Alouatta puruensis by Boa constrictor.

    Science.gov (United States)

    Quintino, Erika Patrícia; Bicca-Marques, Júlio César

    2013-10-01

    Reports of successful predator attacks on primates are rare. Primates from all major radiations are particularly susceptible to raptors, carnivores, and snakes. Among New World primates, reports of snake predation are limited to medium- and small-bodied species. Here, we report the first documented case of successful predation of an atelid by a snake-an adult female Purús red howler monkey, Alouatta puruensis, that was subdued by a ca. 2-m-long Boa constrictor in an arboreal setting at a height of 7.5 m above the ground. The victim belonged to a group composed of six individuals (one adult male, two adult females, two juveniles, and one infant) that inhabited a ca. 2.5-ha forest fragment in the State of Rondônia, western Brazilian Amazon. The boa applied the species' typical hunting behavior of striking and immediately coiling around its prey and then killing it through constriction (probably in less than 5 min), but the entire restraint period lasted 38 min. The attack occurred around noon. The howler was swallowed head-first in 76 min. The only group member to respond to the distress vocalization emitted by the victim was the other adult female, which was closest to the location where the attack occurred. This female ran toward the snake, also vocalizing, and hit it with her hands several times, but the snake did not react and she moved off to a nearby tree from where she watched most of the interaction. The remaining group members stayed resting at a height approximately 15 m above the victim in a nearby tree without showing any overt signs of stress, except for a single whimper vocalization. This event indicates that even large-bodied atelids are vulnerable to predation by large snakes and suggests that B. constrictor may be a more common predator of primates. PMID:23917944

  8. Collective behavior and predation success in a predator-prey model inspired by hunting bats

    Science.gov (United States)

    Lin, Yuan; Abaid, Nicole

    2013-12-01

    We establish an agent-based model to study the impact of prey behavior on the hunting success of predators. The predators and prey are modeled as self-propelled particles moving in a three-dimensional domain and subject to specific sensing abilities and behavioral rules inspired by bat hunting. The predators randomly search for prey. The prey either align velocity directions with peers, defined as "interacting" prey, or swarm "independently" of peer presence; both types of prey are subject to additive noise. In a simulation study, we find that interacting prey using low noise have the maximum predation avoidance because they form localized large groups, while they suffer high predation as noise increases due to the formation of broadly dispersed small groups. Independent prey, which are likely to be uniformly distributed in the domain, have higher predation risk under a low noise regime as they traverse larger spatial extents. These effects are enhanced in large prey populations, which exhibit more ordered collective behavior or more uniform spatial distribution as they are interacting or independent, respectively.

  9. Predator odours attract other predators, creating an olfactory web of information.

    Science.gov (United States)

    Banks, Peter B; Daly, Andrew; Bytheway, Jenna P

    2016-05-01

    Many studies have reported the aversive reactions of prey towards a predator's odour signals (e.g. urine marks), a behaviour widely thought to reduce the risk of predation by the predator. However, because odour signals persist in the environment, they are vulnerable to exploitation and eavesdropping by predators, prey and conspecifics. As such, scent patches created by one species might attract other species interested in information about their enemies. We studied this phenomenon by examining red fox investigation of odours from conspecifics and competing species in order to understand what prey are responding to when avoiding the odours of a predator. Surprisingly, foxes showed limited interest in conspecific odours but were highly interested in the odours of their competitors (wild dogs and feral cats), suggesting that odours are likely to play an important role in mediating competitive interactions. Importantly, our results identify that simple, dyadic interpretations of prey responses to a predator odour (i.e. cat odour = risk of cat encounter = fear of cats) can no longer be assumed in ecological or psychology research. Instead, interactions mediated by olfactory cues are more complex than previously thought and are likely to form a complicated olfactory web of interactions. PMID:27194283

  10. PERMANENCE OF A NONLINEAR PERIODIC PREDATOR-PREY SYSTEM WITH PREY DISPERSAL AND PREDATOR DENSITY-INDEPENDENCE

    Institute of Scientific and Technical Information of China (English)

    Lijuan Chen; Junyan Xu

    2009-01-01

    In this paper,a set of sufficient conditions which ensure the permanence of a nonlinear periodic predator-prey system with prey dispersal and predator density-independence are obtained,where the prey species can disperse among n patches,while the density-independent predator is confined to one of the patches and cannot disperse. Our results generalize some known results.

  11. PERMANENCE OF A NONLINEAR PERIODIC PREDATOR-PREY SYSTEM WITH PREY DISPERSAL AND PREDATOR DENSITY-INDEPENDENCE

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper,a set of suffcient conditions which ensure the permanence of a nonlinear periodic predator-prey system with prey dispersal and predator density-independence are obtained,where the prey species can disperse among n patches,while the density-independent predator is confined to one of the patches and cannot disperse. Our results generalize some known results.

  12. Revealing the role of predator interference in a predator-prey system with disease in prey population

    DEFF Research Database (Denmark)

    Chakraborty, Subhendu; Kooi, B.W.; Biswas, B.;

    2015-01-01

    Predation on a species subjected to an infectious disease can affect both the infection level and the population dynamics. There is an ongoing debate about the act of managing disease in natural populations through predation. Recent theoretical and empirical evidence shows that predation on......; otherwise it may lead to ecological disaster...

  13. Ciliary neurotrophic factor activates leptin-like pathways and reduces body fat, without cachexia or rebound weight gain, even in leptin-resistant obesity

    OpenAIRE

    Lambert, P. D.; Anderson, K. D.; Sleeman, M. W.; Wong, V.; Tan, J.; Hijarunguru, A.; Corcoran, T L; Murray, J. D.; Thabet, K. E.; Yancopoulos, G D; Wiegand, S J

    2001-01-01

    Ciliary Neurotrophic Factor (CNTF) was first characterized as a trophic factor for motor neurons in the ciliary ganglion and spinal cord, leading to its evaluation in humans suffering from motor neuron disease. In these trials, CNTF caused unexpected and substantial weight loss, raising concerns that it might produce cachectic-like effects. Countering this possibility was the suggestion that CNTF was working via a leptin-like mechanism to cause weight loss, based on the find...

  14. Differences between the neurogenic and proliferative abilities of Müller glia with stem cell characteristics and the ciliary epithelium from the adult human eye

    OpenAIRE

    Bhatia, Bhairavi; Jayaram, Hari; Singhal, Shweta; Jones, Megan F; Limb, G. Astrid

    2011-01-01

    Much controversy has arisen on the nature and sources of stem cells in the adult human retina. Whilst ciliary epithelium has been thought to constitute a source of neural stem cells, a population of Müller glia in the neural retina has also been shown to exhibit neurogenic characteristics. This study aimed to compare the neurogenic and proliferative abilities between these two major cell populations. It also examined whether differences exist between the pigmented and non-pigmented ciliary ep...

  15. Gene

    Data.gov (United States)

    U.S. Department of Health & Human Services — Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes,...

  16. Conjugate coupling in ecosystems: Cross-predation stabilizes food webs

    International Nuclear Information System (INIS)

    Highlights: • We study two predator–prey models coupled via cross-predation (conjugate coupling). • Appropriate cross-predation levels can lead to amplitude death. • An instance of extreme multistability in identical coupled systems is reported. - Abstract: We study the dynamics of two predator–prey systems that are coupled via cross-predation, in which each predator consumes also the other prey. This setup constitutes a model system in which conjugate coupling emerges naturally and denotes the transition from two separate food chains to a food web. We show that cross-predation of a certain strength leads to amplitude death stabilizing the food web in a new equilibrium

  17. A minimal model of predator-swarm interactions

    CERN Document Server

    Chen, Yuxin

    2014-01-01

    We propose a minimal model of predator-swarm interactions which captures many of the essential dynamics observed in nature. Different outcomes are observed depending on the predator strength. For a "weak" predator, the swarm is able to escape the predator completely. As the strength is increased, the predator is able to catch up with the swarm as a whole, but the individual prey are able to escape by "confusing" the predator: the prey forms a ring with the predator at the center. For higher predator strength, complex chasing dynamics are observed which can become chaotic. For even higher strength, the predator is able to successfully capture the prey. Our model is simple enough to be amenable to a full mathematical analysis which is used to predict the shape of the swarm as well as the resulting predator-prey dynamics as a function of model parameters. We show that as the predator strength is increased, there is a transition (due to a Hopf bifurcation) from confusion state to chasing dynamics, and we compute ...

  18. Foxg1-Cre Mediated Lrp2 Inactivation in the Developing Mouse Neural Retina, Ciliary and Retinal Pigment Epithelia Models Congenital High Myopia.

    Directory of Open Access Journals (Sweden)

    Olivier Cases

    Full Text Available Myopia is a common ocular disorder generally due to increased axial length of the eye-globe. Its extreme form high myopia (HM is a multifactorial disease leading to retinal and scleral damage, visual impairment or loss and is an important health issue. Mutations in the endocytic receptor LRP2 gene result in Donnai-Barrow (DBS and Stickler syndromes, both characterized by HM. To clearly establish the link between Lrp2 and congenital HM we inactivated Lrp2 in the mouse forebrain including the neural retina and the retinal and ciliary pigment epithelia. High resolution in vivo MRI imaging and ophthalmological analyses showed that the adult Lrp2-deficient eyes were 40% longer than the control ones mainly due to an excessive elongation of the vitreal chamber. They had an apparently normal intraocular pressure and developed chorioretinal atrophy and posterior scleral staphyloma features reminiscent of human myopic retinopathy. Immunomorphological and ultrastructural analyses showed that increased eye lengthening was first observed by post-natal day 5 (P5 and that it was accompanied by a rapid decrease of the bipolar, photoreceptor and retinal ganglion cells, and eventually the optic nerve axons. It was followed by scleral thinning and collagen fiber disorganization, essentially in the posterior pole. We conclude that the function of LRP2 in the ocular tissues is necessary for normal eye growth and that the Lrp2-deficient eyes provide a unique tool to further study human HM.

  19. Ciliary Neurotrophic Factor Promotes the Migration of Corneal Epithelial Stem/progenitor Cells by Up-regulation of MMPs through the Phosphorylation of Akt.

    Science.gov (United States)

    Chen, Jialin; Chen, Peng; Backman, Ludvig J; Zhou, Qingjun; Danielson, Patrik

    2016-01-01

    The migration of limbal epithelial stem cells is important for the homeostasis and regeneration of corneal epithelium. Ciliary neurotrophic factor (CNTF) has been found to promote corneal epithelial wound healing by activating corneal epithelial stem/progenitor cells. However, the possible effect of CNTF on the migration of corneal epithelial stem/progenitor cells is not clear. This study found the expression of CNTF in mouse corneal epithelial stem/progenitor cells (TKE2) to be up-regulated after injury, on both gene and protein level. CNTF promoted migration of TKE2 in a dose-dependent manner and the peak was seen at 10 ng/ml. The phosphorylation level of Akt (p-Akt), and the expression of MMP3 and MMP14, were up-regulated after CNTF treatment both in vitro and in vivo. Akt and MMP3 inhibitor treatment delayed the migration effect by CNTF. Finally, a decreased expression of MMP3 and MMP14 was observed when Akt inhibitor was applied both in vitro and in vivo. This study provides new insights into the role of CNTF on the migration of corneal epithelial stem/progenitor cells and its inherent mechanism of Up-regulation of matrix metalloproteinases through the Akt signalling pathway. PMID:27174608

  20. OFD1 and flotillins are integral components of a ciliary signaling protein complex organized by polycystins in renal epithelia and odontoblasts.

    Directory of Open Access Journals (Sweden)

    Stephanie Jerman

    Full Text Available Mutation of the X-linked oral-facial-digital syndrome type 1 (OFD1 gene is embryonic lethal in males and results in craniofacial malformations and adult onset polycystic kidney disease in females. While the OFD1 protein localizes to centriolar satellites, centrosomes and basal bodies, its cellular function and how it relates to cystic kidney disease is largely unknown. Here, we demonstrate that OFD1 is assembled into a protein complex that is localized to the primary cilium and contains the epidermal growth factor receptor (EGFR and domain organizing flotillin proteins. This protein complex, which has similarity to a basolateral adhesion domain formed during cell polarization, also contains the polycystin proteins that when mutant cause autosomal dominant polycystic kidney disease (ADPKD. Importantly, in human ADPKD cells where mutant polycystin-1 fails to localize to cilia, there is a concomitant loss of localization of polycystin-2, OFD1, EGFR and flotillin-1 to cilia. Together, these data suggest that polycystins are necessary for assembly of a novel flotillin-containing ciliary signaling complex and provide a molecular rationale for the common renal pathologies caused by OFD1 and PKD mutations.

  1. RPGR-containing protein complexes in syndromic and non-syndromic retinal degeneration due to ciliary dysfunction

    Indian Academy of Sciences (India)

    Carlos A. Murga-Zamalloa; Anand Swaroop; Hemant Khanna

    2009-12-01

    Dysfunction of primary cilia due to mutations in cilia-centrosomal proteins is associated with pleiotropic disorders. The primary (or sensory) cilium of photoreceptors mediates polarized trafficking of proteins for efficient phototransduction. Retinitis pigmentosa GTPase regulator (RPGR) is a cilia-centrosomal protein mutated in >70% of X-linked RP cases and 10%–20% of simplex RP males. Accumulating evidence indicates that RPGR may facilitate the orchestration of multiple ciliary protein complexes. Disruption of these complexes due to mutations in component proteins is an underlying cause of associated photoreceptor degeneration. Here, we highlight the recent developments in understanding the mechanism of cilia-dependent photoreceptor degeneration due to mutations in RPGR and RPGR-interacting proteins in severe genetic diseases, including retinitis pigmentosa, Leber congenital amaurosis (LCA), Joubert syndrome, and Senior–Loken syndrome, and explore the physiological relevance of photoreceptor ciliary protein complexes.

  2. The interplay between RPGR, PDEδ and Arl2/3 regulate the ciliary targeting of farnesylated cargo

    Science.gov (United States)

    Wätzlich, Denise; Vetter, Ingrid; Gotthardt, Katja; Miertzschke, Mandy; Chen, Yong-Xiang; Wittinghofer, Alfred; Ismail, Shehab

    2013-01-01

    Defects in primary cilia result in human diseases known as ciliopathies. The retinitis pigmentosa GTPase regulator (RPGR), mutated in the most severe form of the eye disease, is located at the transition zone of the ciliary organelle. The RPGR-interacting partner PDEδ is involved in trafficking of farnesylated ciliary cargo, but the significance of this interaction is unknown. The crystal structure of the propeller domain of RPGR shows the location of patient mutations and how they perturb the structure. The RPGR·PDEδ complex structure shows PDEδ on a highly conserved surface patch of RPGR. Biochemical experiments and structural considerations show that RPGR can bind with high affinity to cargo-loaded PDEδ and exposes the Arl2/Arl3-binding site on PDEδ. On the basis of these results, we propose a model where RPGR is acting as a scaffold protein recruiting cargo-loaded PDEδ and Arl3 to release lipidated cargo into cilia. PMID:23559067

  3. CCDC151 mutations cause primary ciliary dyskinesia by disruption of the outer dynein arm docking complex formation

    DEFF Research Database (Denmark)

    Hjeij, Rim; Onoufriadis, Alexandros; Watson, Christopher M;

    2014-01-01

    disorder of ciliary and flagellar dysmotility characterized by chronic upper and lower respiratory infections and defects in laterality. Here, by combined high-throughput mapping and sequencing, we identified CCDC151 loss-of-function mutations in five affected individuals from three independent families...... whose cilia showed a complete loss of ODAs and severely impaired ciliary beating. Consistent with the laterality defects observed in these individuals, we found Ccdc151 expressed in vertebrate left-right organizers. Homozygous zebrafish ccdc151(ts272a) and mouse Ccdc151(Snbl) mutants display a spectrum...... of situs defects associated with complex heart defects. We demonstrate that CCDC151 encodes an axonemal coiled coil protein, mutations in which abolish assembly of CCDC151 into respiratory cilia and cause a failure in axonemal assembly of the ODA component DNAH5 and the ODA-DC-associated components...

  4. Beyond Predation: The Zoophytophagous Predator Macrolophus pygmaeus Induces Tomato Resistance against Spider Mites.

    Science.gov (United States)

    Pappas, Maria L; Steppuhn, Anke; Geuss, Daniel; Topalidou, Nikoleta; Zografou, Aliki; Sabelis, Maurice W; Broufas, George D

    2015-01-01

    Many predatory insects that prey on herbivores also feed on the plant, but it is unknown whether plants affect the performance of herbivores by responding to this phytophagy with defence induction. We investigate whether the prior presence of the omnivorous predator Macrolophus pygmaeus (Rambur) on tomato plants affects plant resistance against two different herbivore species. Besides plant-mediated effects of M. pygmaeus on herbivore performance, we examined whether a plant defence trait that is known to be inducible by herbivory, proteinase inhibitors (PI), may also be activated in response to the interactions of this predator with the tomato plant. We show that exposing tomato plants to the omnivorous predator M. pygmaeus reduced performance of a subsequently infesting herbivore, the two-spotted spider mite Tetranychus urticae Koch, but not of the greenhouse whitefly Trialeurodes vaporariorum (Westwood). The spider-mite infested tomato plants experience a lower herbivore load, i.e., number of eggs deposited and individuals present, when previously exposed to the zoophytophagous predator. This effect is not restricted to the exposed leaf and persists on exposed plants for at least two weeks after the removal of the predators. The decreased performance of spider mites as a result of prior exposure of the plant to M. pygmaeus is accompanied by a locally and systemically increased accumulation of transcripts and activity of proteinase inhibitors that are known to be involved in plant defence. Our results demonstrate that zoophytophagous predators can induce plant defence responses and reduce herbivore performance. Hence, the suppression of populations of certain herbivores via consumption may be strengthened by the induction of plant defences by zoophytophagous predators. PMID:25974207

  5. Predator odor recognition and antipredatory response in fish: does the prey know the predator diel rhythm?

    Science.gov (United States)

    Ylönen, Hannu; Kortet, Raine; Myntti, Janne; Vainikka, Anssi

    2007-01-01

    We studied in a laboratory experiment using stream tanks if two percid prey fish, the perch ( Perca fluviatilis) and the ruffe ( Gymnocephalus cernuus), can recognize and respond to increased predation risk using odors of two piscivores, the pike ( Esox lucius) and the burbot ( Lota lota). Burbot is night-active most of the year but pike hunts predominantly visually whenever there is enough light. Perch is a common day-active prey of pike and dark-active ruffe that of burbot. We predicted that besides recognizing the predator odors, the prey species would respond more strongly to odors of the predator which share the same activity pattern. Both perch and ruffe clearly responded to both predator fish odors. They decreased movements and erected the spiny dorsal fins. Fin erection showed clearly the black warning ornamentation in the fin and thus erected fin may function besides as mechanical defense also as warning ornament for an approaching predator. No rapid escape movements were generally observed. Both perch and ruffe responded more strongly to pike odor than to burbot. There were no clear differences in response between day and night. In conclusion, we were able to verify clear predator odor recognition by both prey fish. Both perch and ruffe responded to both predator odors and it seemed that pike forms a stronger threat for both prey species. Despite of diel activity differences both perch and ruffe used the same antipredatory strategies, but the day-active perch seemed to have a more flexible antipredatory behavior by responding more strongly to burbot threat during the night when burbot is active.

  6. Beyond Predation: The Zoophytophagous Predator Macrolophus pygmaeus Induces Tomato Resistance against Spider Mites

    Science.gov (United States)

    Pappas, Maria L.; Steppuhn, Anke; Geuss, Daniel; Topalidou, Nikoleta; Zografou, Aliki; Broufas, George D.

    2015-01-01

    Many predatory insects that prey on herbivores also feed on the plant, but it is unknown whether plants affect the performance of herbivores by responding to this phytophagy with defence induction. We investigate whether the prior presence of the omnivorous predator Macrolophus pygmaeus (Rambur) on tomato plants affects plant resistance against two different herbivore species. Besides plant-mediated effects of M. pygmaeus on herbivore performance, we examined whether a plant defence trait that is known to be inducible by herbivory, proteinase inhibitors (PI), may also be activated in response to the interactions of this predator with the tomato plant. We show that exposing tomato plants to the omnivorous predator M. pygmaeus reduced performance of a subsequently infesting herbivore, the two-spotted spider mite Tetranychus urticae Koch, but not of the greenhouse whitefly Trialeurodes vaporariorum (Westwood). The spider-mite infested tomato plants experience a lower herbivore load, i.e., number of eggs deposited and individuals present, when previously exposed to the zoophytophagous predator. This effect is not restricted to the exposed leaf and persists on exposed plants for at least two weeks after the removal of the predators. The decreased performance of spider mites as a result of prior exposure of the plant to M. pygmaeus is accompanied by a locally and systemically increased accumulation of transcripts and activity of proteinase inhibitors that are known to be involved in plant defence. Our results demonstrate that zoophytophagous predators can induce plant defence responses and reduce herbivore performance. Hence, the suppression of populations of certain herbivores via consumption may be strengthened by the induction of plant defences by zoophytophagous predators. PMID:25974207

  7. Ascorbate blocks endothelium-derived hyperpolarizing factor (EDHF)-mediated vasodilatation in the bovine ciliary vascular bed and rat mesentery

    OpenAIRE

    McNeish, Alister J.; Wilson, William S; Martin, William

    2002-01-01

    The effects of ascorbate were assessed on vasodilatation mediated by endothelium-derived hyperpolarizing factor (EDHF) in the ciliary vascular bed of the bovine isolated perfused eye and in the rat isolated perfused mesenteric arterial bed.In the bovine eye, EDHF-mediated vasodilator responses induced by acetylcholine or bradykinin were powerfully blocked when ascorbate (50 μM) was included in the perfusion medium for at least 120 min; with acetylcholine a normally-masked muscarinic vasoconst...

  8. Effects of ciliary neurotrophic factor on retrograde cell reaction after facial nerve crush in young adults rats

    OpenAIRE

    Gispen, W.H.; Ulenkate, H.J.L.M.; Jennekens, F.G.I.

    1996-01-01

    Locally applied ciliary neurotrophic factor (CNTF) has a powerful effect on retrograde axonal reaction following facial nerve crush in neonatal rats. We examined whether it also exerts a strong effect on retrograde axonal reaction in young adult rats when administered subcutaneously. The dose was 1 mg/kg body weight, three times a week, similar to that used in a previous experiment in which CNTF was reported to have an effect. We studied changes in the morphology of the motor nerve cell bodie...

  9. Effect of Locally Administered Ciliary Neurotrophic Factor on the Survival of Transected and Repaired Adult Sheep Facial Nerve

    OpenAIRE

    Rashid Al Abri; Arif Ali Kolethekkat; Kelleher, Michael O.; Lynn M. Myles; Michael A. Glasby

    2014-01-01

    Objective: to determine whether the administration of Ciliary Neurotrophic Factor (CNTF) at the site of repaired facial nerve enhances regeneration in the adult sheep model. Methods: Ten adult sheep were divided into 2 groups: control and study group (CNTF group). In the CNTF group, the buccal branch of the facial nerve was transected and then repaired by epineural sutures. CNTF was injected over the left depressor labii maxillaris muscle in the vicinity of the transected and repaired ner...

  10. Opposite effects of a high-fat diet and calorie restriction on ciliary neurotrophic factor signalling in the mouse hypothalamus

    OpenAIRE

    AntonioGiordano; SaverioCinti

    2013-01-01

    In the mouse hypothalamus, ciliary neurotrophic factor (CNTF) is mainly expressed by ependymal cells and tanycytes of the ependymal layer covering the third ventricle. Since exogenously administered CNTF causes reduced food intake and weight loss, we tested whether endogenous CNTF might be involved in energy balance regulation. We thus evaluated CNTF production and responsiveness in the hypothalamus of mice fed a high-fat diet (HFD), of ob/ob obese mice, and of mice fed a calorie restriction ...

  11. Ciliary neurotrophic factor cell-based delivery prevents synaptic impairment and improves memory in mouse models of Alzheimer's disease.

    OpenAIRE

    Garcia, Pierre

    2010-01-01

    The development of novel therapeutic strategies for Alzheimer’s disease (AD) represents one of the biggest unmet medical needs today. Application of neurotrophic factors able to modulate neuronal survival and synaptic connectivity is a promising therapeutic approach for AD. We aimed to determine whether the loco-regional delivery of ciliary neurotrophic factor (CNTF) could prevent amyloid-beta oligomer-induced synaptic damages and associated cognitive impairments that typify AD. To ensure lo...

  12. gp130 signaling in proopiomelanocortin neurons mediates the acute anorectic response to centrally applied ciliary neurotrophic factor

    OpenAIRE

    Janoschek, Ruth; Plum, Leona; Koch, Linda; Münzberg, Heike; Diano, Sabrina; Shanabrough, Marya; Müller, Werner; Horvath, Tamas L.; Brüning, Jens C.

    2006-01-01

    Ciliary neurotrophic factor (CNTF) exerts anorectic effects by overcoming leptin resistance via activation of hypothalamic neurons. However, the exact site of CNTF action in the hypothalamus has not yet been identified. Using Cre-loxP-mediated recombination in vivo, we have selectively ablated the common cytokine signaling chain gp130, which is required for functional CNTF signaling, in proopiomelanocortin (POMC)-expressing neurons. POMC-specific gp130 knockout mice exhibit unaltered numbers ...

  13. Opposite effects of a high-fat diet and calorie restriction on ciliary neurotrophic factor signaling in the mouse hypothalamus

    OpenAIRE

    Severi, Ilenia; Perugini, Jessica; Mondini, Eleonora; Smorlesi, Arianna; Frontini, Andrea; Cinti, Saverio; Giordano, Antonio

    2013-01-01

    In the mouse hypothalamus, ciliary neurotrophic factor (CNTF) is mainly expressed by ependymal cells and tanycytes of the ependymal layer covering the third ventricle. Since exogenously administered CNTF causes reduced food intake and weight loss, we tested whether endogenous CNTF might be involved in energy balance regulation. We thus evaluated CNTF production and responsiveness in the hypothalamus of mice fed a high-fat diet (HFD), of ob/ob obese mice, and of mice fed a calorie restriction ...

  14. Synthesis and localization of ciliary neurotrophic factor in the sciatic nerve of the adult rat after lesion and during regeneration

    OpenAIRE

    Sendtner, Michael; Stöckli, K. A.; Thoenen, Hans

    2009-01-01

    Ciliary neurotrophic factor (CNTF) is expressed in high quantities in Schwann cells of peripheral nerves during postnatal development of the rat. The absence of a hydrophobic leader sequence and the immunohistochemical localization of CNTF within the cytoplasm of these cells indicate that the factor might not be available to responsive neurons under physiological conditions. However, CNTF supports the survival of a variety of embryonic neurons, including spinal motoneurons in culture. Moreove...

  15. Ciliary Neurotrophic Factor Stimulates Muscle Glucose Uptake by a PI3-Kinase–Dependent Pathway That Is Impaired With Obesity

    OpenAIRE

    Steinberg, Gregory R.; Watt, Matthew J.; Ernst, Matthias; Birnbaum, Morris J.; Kemp, Bruce E.; Jørgensen, Sebastian Beck

    2009-01-01

    OBJECTIVE Ciliary neurotrophic factor (CNTF) reverses muscle insulin resistance by increasing fatty acid oxidation through gp130-LIF receptor signaling to the AMP-activated protein kinase (AMPK). CNTF also increases Akt signaling in neurons and adipocytes. Because both Akt and AMPK regulate glucose uptake, we investigated muscle glucose uptake in response to CNTF signaling in lean and obese mice. RESEARCH DESIGN AND METHODS Mice were injected intraperitoneally with saline or CNTF, and blood g...

  16. Identification of ciliary neurotrophic factor (CNTF) residues essential for leukemia inhibitory factor receptor binding and generation of CNTF receptor antagonists.

    OpenAIRE

    Di Marco, A; Gloaguen, I; Graziani, R; Paonessa, G; Saggio, I; Hudson, K R; Laufer, R

    1996-01-01

    Ciliary neurotrophic factor (CNTF) drives the sequential assembly of a receptor complex containing the ligand-specific alpha-receptor subunit (CNTFR alpha) and the signal transducers gp130 and leukemia inhibitory factor receptor-beta (LIFR). The D1 structural motif, located at the beginning of the D-helix of human CNTF, contains two amino acid residues, F152 and K155, which are conserved among all cytokines that signal through LIFR. The functional importance of these residues was assessed by ...

  17. Identification of the probable site of synthesis of butyrylcholinesterase in the superior cervical and ciliary ganglia of the cat.

    OpenAIRE

    Uchida, E; Koelle, G B

    1983-01-01

    The source of butyrylcholinesterase (acylcholine acylhydrolase, EC 3.1.1.8) in the ganglion cells of the cat superior cervical and ciliary ganglia has been elusive, inasmuch as the enzyme is present in high concentrations in the neuropil, where it is confined largely to the dendritic and perikaryonal plasma membranes, but appears to be absent from the perikarya. In the present study, ganglionic butyrylcholinesterase was near-totally inactivated by the injection of tetramonoisopropyl pyyrophos...

  18. Ciliary neurotrophic factor promotes motor reinnervation of the musculocutaneous nerve in an experimental model of end-to-side neurorrhaphy

    OpenAIRE

    Čelakovský Pavel; Stejskal Lubomír; Raška Otakar; Klusáková Ilona; Dubový Petr; Haninec Pavel

    2011-01-01

    Abstract Background It is difficult to repair nerve if proximal stump is unavailable or autogenous nerve grafts are insufficient for reconstructing extensive nerve damage. Therefore, alternative methods have been developed, including lateral anastomosis based on axons' ability to send out collateral sprouts into denervated nerve. The different capacity of a sensory or motor axon to send a sprout is controversial and may be controlled by cytokines and/or neurotrophic factors like ciliary neuro...

  19. Association of vitamin D receptor gene start codon (Fok1 polymorphism with high myopia

    Directory of Open Access Journals (Sweden)

    Sandhya Annamaneni

    2011-01-01

    Conclusion : The results suggest that VDR gene might not be playing a direct role in the development of myopia, but might contribute indirectly to the risk conferred by mechanical stress factors or growth/development related factors through its role in calcium homeostasis and regulation of ciliary muscle function.

  20. Dose-dependent neuroprotective effect of ciliary neurotrophic factor delivered via tetracycline-regulated lentiviral vectors in the quinolinic acid rat model of Huntington's disease.

    Science.gov (United States)

    Régulier, E; Pereira de Almeida, L; Sommer, B; Aebischer, P; Déglon, N

    2002-11-01

    The ability to regulate gene expression constitutes a prerequisite for the development of gene therapy strategies aimed at the treatment of neurologic disorders. In the present work, we used tetracycline (Tet)-regulated lentiviral vectors to investigate the dose-dependent neuroprotective effect of human ciliary neurotrophic factor (CNTF) in the quinolinic acid (QA) model of Huntington's disease (HD). The Tet system was split in two lentiviruses, the first one containing the CNTF or green fluorescent protein (GFP) cDNAs under the control of the Tet-response element (TRE) and a second vector encoding the transactivator (tTA). Preliminary coinfection study demonstrated that 63.8% +/- 2.0% of infected cells contain at least two viral copies. Adult rats were then injected with CNTF- and GFP-expressing viral vectors followed 3 weeks later by an intrastriatal administration of QA. A significant reduction of apomorphine-induced rotations was observed in the CNTF-on group. In contrast, GFP-treated animals or CNTF-off rats displayed an ipsilateral turning behavior in response to apomorphine. A selective sparing of DARPP-32-, choline acetyltransferase (ChAT)-, and NADPH-d-positive neurons was observed in the striatum of CNTF-on rats compared to GFP animals and CNTF-off group. Enzyme-linked immunosorbent assay (ELISA) performed on striatal samples of rats sacrificed at the same time point indicated that this neuroprotective effect was associated with the production of 15.5 +/- 4.7 ng CNTF per milligram of protein whereas the residual CNTF expression in the off state (0.54 +/- 0.02 ng/mg of protein) was not sufficient to protect against QA toxicity. These results establish the proof of principle of neurotrophic factor dosing for neurodegenerative diseases and demonstrate the feasibility of lentiviral-mediated tetracycline-regulated gene transfer in the brain. PMID:12427308

  1. Sonic Hedgehog dependent phosphorylation by CK1α and GRK2 is required for ciliary accumulation and activation of smoothened.

    Directory of Open Access Journals (Sweden)

    Yongbin Chen

    2011-06-01

    Full Text Available Hedgehog (Hh signaling regulates embryonic development and adult tissue homeostasis through the GPCR-like protein Smoothened (Smo, but how vertebrate Smo is activated remains poorly understood. In Drosophila, Hh dependent phosphorylation activates Smo. Whether this is also the case in vertebrates is unclear, owing to the marked sequence divergence between vertebrate and Drosophila Smo (dSmo and the involvement of primary cilia in vertebrate Hh signaling. Here we demonstrate that mammalian Smo (mSmo is activated through multi-site phosphorylation of its carboxyl-terminal tail by CK1α and GRK2. Phosphorylation of mSmo induces its active conformation and simultaneously promotes its ciliary accumulation. We demonstrate that graded Hh signals induce increasing levels of mSmo phosphorylation that fine-tune its ciliary localization, conformation, and activity. We show that mSmo phosphorylation is induced by its agonists and oncogenic mutations but is blocked by its antagonist cyclopamine, and efficient mSmo phosphorylation depends on the kinesin-II ciliary motor. Furthermore, we provide evidence that Hh signaling recruits CK1α to initiate mSmo phosphorylation, and phosphorylation further increases the binding of CK1α and GRK2 to mSmo, forming a positive feedback loop that amplifies and/or sustains mSmo phosphorylation. Hence, despite divergence in their primary sequences and their subcellular trafficking, mSmo and dSmo employ analogous mechanisms for their activation.

  2. The Great White Guppy: Top Predator

    Science.gov (United States)

    Michalski, G. M.

    2011-12-01

    Nitrogen isotopes are often used to trace the trophic level of members of an ecosystem. As part of a stable isotope biogeochemistry and forensics course at Purdue University, students are introduced to this concept by analyzing nitrogen isotopes in sea food purchased from local grocery stores. There is a systematic increase in 15N/14N ratios going from kelp to clams/shrimp, to sardines, to tuna and finally to shark. These enrichments demonstrate how nitrogen is enriched in biomass as predators consume prey. Some of the highest nitrogen isotope enrichments observed, however, are in the common guppy. We investigated a number of aquarium fish foods and find they typically have high nitrogen isotope ratios because they are made form fish meal that is produced primarily from the remains of predator fish such as tuna. From, a isotope perspective, the guppy is the top of the food chain, more ferocious than even the Great White shark.

  3. Cumulative human impacts on marine predators

    DEFF Research Database (Denmark)

    Maxwell, Sara M; Hazen, Elliott L; Bograd, Steven J;

    2013-01-01

    Stressors associated with human activities interact in complex ways to affect marine ecosystems, yet we lack spatially explicit assessments of cumulative impacts on ecologically and economically key components such as marine predators. Here we develop a metric of cumulative utilization and impact...... planning the use of marine resources.......Stressors associated with human activities interact in complex ways to affect marine ecosystems, yet we lack spatially explicit assessments of cumulative impacts on ecologically and economically key components such as marine predators. Here we develop a metric of cumulative utilization and impact...... Sanctuaries. High variation in underlying species and cumulative impact distributions means that neither alone is sufficient for effective spatial management. Instead, comprehensive management approaches accounting for both cumulative human impacts and trade-offs among multiple stressors must be applied in...

  4. Bacterial symbioses. Predation and mutually beneficial associations.

    Science.gov (United States)

    Esteve, I; Gaju, N

    1999-06-01

    The endosymbiotic theory, which has proved to explain the origin of mitochondria and chloroplasts, also posits the origin of nucleus and other cellular organelles that could have derived from ancient relationships among bacteria. It seems that predation might have been a prerequisite to the establishment of symbiosis as a source of evolutionary novelty. This review describes current different examples of bacteria able not only to attack and degrade other bacteria, but also to establish stable symbiotic relationships with different eukaryotic organisms. PMID:10943397

  5. Arctic cephalopod distributions and their associated predators

    OpenAIRE

    Gardiner, Kathleen; Terry A Dick

    2010-01-01

    Cephalopods are key species of the eastern Arctic marine food web, both as prey and predator. Their presence in the diets of Arctic fish, birds and mammals illustrates their trophic importance. There has been considerable research on cephalopods (primarily Gonatus fabricii) from the north Atlantic and the west side of Greenland, where they are considered a potential fishery and are taken as a by-catch. By contrast, data on the biogeography of Arctic cephalopods are still incomplete. This stud...

  6. Distribution of mammalian predator in fragmented landscape

    Czech Academy of Sciences Publication Activity Database

    Koubová, M.; Svobodová, J.; Kreisinger, J.; Šálek, Martin; Šálek, M. E.; Albrecht, Tomáš

    Brno : Ústav biologie obratlovců AV ČR, 2010 - (Bryja, J.; Zasadil, P.). s. 127-128 ISBN 978-80-87189-07-8. [Zoologické dny. 11.02.2010-12.02.2010, Praha] Institutional research plan: CEZ:AV0Z60930519 Keywords : predators Subject RIV: EG - Zoology http://zoo.ivb.cz/doc/sborniky/sbornik_2010.pdf

  7. Predator diversity hotspots in the blue ocean

    OpenAIRE

    Worm, Boris; Lotze, Heike K.; Myers, Ransom A.

    2003-01-01

    Concentrations of biodiversity, or hotspots, represent conservation priorities in terrestrial ecosystems but remain largely unexplored in marine habitats. In the open ocean, many large predators such as tunas, sharks, billfishes, and sea turtles are of current conservation concern because of their vulnerability to overfishing and ecosystem role. Here we use scientific-observer records from pelagic longline fisheries in the Atlantic and Pacific Oceans to show that ocean...

  8. Obstacle and predator avoidance by a flock

    OpenAIRE

    Mecholsky, Nicholas A.; Ott, Edward; Antonsen Jr., Thomas M.

    2009-01-01

    The modeling and investigation of the dynamics and configurations of animal groups is a subject of growing attention. In this paper, we present a continuum model of flocking and use it to investigate the reaction of a flock to an obstacle or an attacking predator. We show that the flock response is in the form of density disturbances that resemble Mach cones whose configuration is determined by the anisotropic propagation of waves through the flock. We analytically and numerically test relati...

  9. A tropical horde of counterfeit predator eyes

    OpenAIRE

    Janzen, Daniel H; Hallwachs, Winnie; Burns, John M.

    2010-01-01

    We propose that the many different, but essentially similar, eye-like and face-like color patterns displayed by hundreds of species of tropical caterpillars and pupae—26 examples of which are displayed here from the dry, cloud, and rain forests of Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica—constitute a huge and pervasive mimicry complex that is evolutionarily generated and sustained by the survival behavior of a large and multispecific array of potential predators: the i...

  10. Hydrological disturbance diminishes predator control in wetlands.

    Science.gov (United States)

    Dorn, Nathan J; Cook, Mark I

    2015-11-01

    Effects of predators on prey populations can be especially strong in aquatic ecosystems, but disturbances may mediate the strength of predator limitation and even allow outbreaks of some prey populations. In a two-year study we investigated the numerical responses of crayfish (Procambarus fallax) and small fishes (Poeciliidae and Fundulidae) to a brief hydrological disturbance in replicated freshwater wetlands with an experimental drying and large predatory fish reduction. The experiment and an in situ predation assay tested the component of the consumer stress model positing that disturbances release prey from predator limitation. In the disturbed wetlands, abundances of large predatory fish were seasonally reduced, similar to dynamics in the Everglades (southern Florida). Densities of small fish were unaffected by the disturbance, but crayfish densities, which were similar across all wetlands before drying, increased almost threefold in the year after the disturbance. Upon re-flooding, juvenile crayfish survival was inversely related to the abundance of large fish across wetlands, but we found no evidence for enhanced algal food quality. At a larger landscape scale (500 km2 of the Everglades), crayfish densities over eight years were positively correlated with the severity of local dry disturbances (up to 99 days dry) during the preceding dry season. In contrast, densities of small-bodied fishes in the same wetlands were seasonally depressed by dry disturbances. The results from our experimental wetland drought and the observations of crayfish densities in the Everglades represent a large-scale example of prey population release following a hydrological disturbance in a freshwater ecosystem. The conditions producing crayfish pulses in the Everglades appear consistent with the mechanics of the consumer stress model, and we suggest crayfish pulses may influence the number of nesting wading birds in the Everglades. PMID:27070017

  11. PREDATOR-PREY SYSTEMS IN PEST MANAGEMENT

    OpenAIRE

    Harper, Carolyn R.

    1991-01-01

    The use of chemical pesticides frequently causes minor pests to become serious problems by disturbing the natural controls that keep them in check. As a result, it is possible to suffer heavier crop losses after pesticides are introduced than before their introduction. Efficient use of pesticides requires complete biological modeling that takes the appropriate predator-prey relationships into account. A bioeconomic model is introduced involving three key species: a primary target pest, a seco...

  12. Top marine predators track Lagrangian coherent structures.

    Science.gov (United States)

    Tew Kai, Emilie; Rossi, Vincent; Sudre, Joel; Weimerskirch, Henri; Lopez, Cristobal; Hernandez-Garcia, Emilio; Marsac, Francis; Garçon, Veronique

    2009-05-19

    Meso- and submesoscales (fronts, eddies, filaments) in surface ocean flow have a crucial influence on marine ecosystems. Their dynamics partly control the foraging behavior and the displacement of marine top predators (tuna, birds, turtles, and cetaceans). In this work we focus on the role of submesoscale structures in the Mozambique Channel in the distribution of a marine predator, the Great Frigatebird. Using a newly developed dynamic concept, the finite-size Lyapunov exponent (FSLE), we identified Lagrangian coherent structures (LCSs) present in the surface flow in the channel over a 2-month observation period (August and September 2003). By comparing seabird satellite positions with LCS locations, we demonstrate that frigatebirds track precisely these structures in the Mozambique Channel, providing the first evidence that a top predator is able to track these FSLE ridges to locate food patches. After comparing bird positions during long and short trips and different parts of these trips, we propose several hypotheses to understand how frigatebirds can follow these LCSs. The birds might use visual and/or olfactory cues and/or atmospheric current changes over the structures to move along these biologic corridors. The birds being often associated with tuna schools around foraging areas, a thorough comprehension of their foraging behavior and movement during the breeding season is crucial not only to seabird ecology but also to an appropriate ecosystemic approach to fisheries in the channel. PMID:19416811

  13. Recent invasion of buffel grass (Cenchrus ciliaris of a natural protected area from the southern Sonoran Desert Invasión reciente de zacate buffel (Cenchrus ciliaris en un área natural protegida del desierto sonorense

    Directory of Open Access Journals (Sweden)

    Erick De la Barrera

    2008-12-01

    Full Text Available The Centro Ecológico de Sonora is a natural protected area where the natural vegetation remained undisturbed at least until 1997. Since then, Cenchrus ciliaris has become a prominent element of the vegetation because of disturbance. Climate, soil properties, population structure and biological activity for C. ciliaris were studied to gain understanding of the ecological mechanisms that favored the invasion by this exotic grass. Mean air temperature and annual rainfall were 24.8°C and 302 mm. The soil was a loamy-sand that was poor in most nutrients, but particularly rich in phosphorus. Pennisetum ciliare was the most abundant species at the Centro Ecológico, representing over one third of total plant ground cover. Basal area for individual plants ranged from less than 1 cm² to almost 1 m². Living leaves per plant increased with precipitation, peaking at 199 leaves in March 2005, and no living leaves were found after 103 days without rain. The environmental conditions prevalent at Centro Ecológico are very favorable for C. ciliaris, whose establishment was apparently triggered by a major disturbance caused by the development of housing projects.El Centro Ecológico de Sonora es un área natural protegida donde la vegetación autóctona permaneció sin disturbios por lo menos hasta 1997. Desde entonces, Cenchrus ciliaris se ha convertido en un elemento prominente de la vegetación. Se estudiaron el clima, las propiedades del suelo, la estructura de la población y la actividad biológica de C. ciliaris, como una aproximación al entendimiento de los mecanismos ecológicos que favorecieron la invasión por este pasto exótico. La temperatura media del aire y la precipitación anual fueron de 24.8 °C y 302 mm. El suelo fue una arena limosa pobre en minerales, pero particularmente rica en fósforo. Cenchrus ciliaris fue la especie herbácea más abundante en el Centro Ecológico, representando más de un tercio de la cobertura vegetal. El

  14. Taphonomy for taxonomists: Implications of predation in small mammal studies

    Science.gov (United States)

    Fernández-Jalvo, Yolanda; Andrews, Peter; Denys, Christiane; Sesé, Carmen; Stoetzel, Emmanuelle; Marin-Monfort, Dolores; Pesquero, Dolores

    2016-05-01

    Predation is one of the most recurrent sources of bone accumulations. The influence of predation is widely studied for large mammal sites where humans, acting as predators, produce bone accumulations similar to carnivore accumulations. Similarly, small mammal fossil sites are mainly occupation levels of predators (nests or dens). In both cases, investigations of past events can be compared with present day equivalents or proxies. Chewing marks are sometimes present on large mammal predator accumulations, but digestion traits are the most direct indication of predation, and evidence for this is always present in small mammal (prey) fossil assemblages. Digestion grades and frequency indicates predator type and this is well established since the publication of Andrews (1990). The identification of the predator provides invaluable information for accurate interpretation of the palaeoenvironment. Traditionally, palaeoenvironmental interpretations are obtained from the taxonomic species identified in the site, but rather than providing direct interpretations of the surrounding palaeoenvironment, this procedure actually describes the dietary preferences of the predators and the type of occupation (nests, marking territory, dens, etc). This paper reviews the identification of traits produced by predators on arvicolins, murins and soricids using a method that may be used equally by taxonomists and taphonomists. It aims to provide the "tools" for taxonomists to identify the predator based on their methodology, which is examining the occlusal surfaces of teeth rather than their lateral aspects. This will greatly benefit both the work of taphonomists and taxonomists to recognize signs of predation and the improvement of subsequent palaeoecological interpretations of past organisms and sites by identifying both the prey and the predator.

  15. Analysis of ependymal ciliary beat pattern and beat frequency using high speed imaging: comparison with the photomultiplier and photodiode methods

    Directory of Open Access Journals (Sweden)

    O'Callaghan Chris

    2012-06-01

    Full Text Available Abstract Background The aim of this study was to compare beat frequency measurements of ependymal cilia made by digital high speed imaging to those obtained using the photomultiplier and modified photodiode techniques. Using high speed video analysis the relationship of the power and recover strokes was also determined. Methods Ciliated strips of ependyma attached to slices from the brain of Wistar rats were incubated at 30°C and observed using a ×50 water immersion lens. Ciliary beat frequency was measured using each of the three techniques: the high speed video, photodiode and photomultiplier. Readings were repeated after 30 minutes incubation at 37°C. Ependymal cilia were observed in slow motion and the precise movement of cilia during the recovery stroke relative to the path travelled during the power stroke was measured. Results The mean (95% confidence intervals beat frequencies determined by the high speed video, photomultiplier and photodiode at 30°C were 27.7 (26.6 to 28.8, 25.5 (24.4 to 26.6 and 20.8 (20.4 to 21.3 Hz, respectively. The mean (95% confidence intervals beat frequencies determined by the high speed video, photomultiplier and photodiode at 37°C were 36.4 (34 to 39.5, 38.4 (36.8 to 39.9 and 18.8 (16.9 to 20.5 Hz. The inter and intra observer reliability for measurement of ciliary beat frequency was 3.8% and 1%, respectively. Ependymal cilia were observed to move in a planar fashion during the power and recovery strokes with a maximum deviation to the right of the midline of 12.1(11.8 to 13.0° during the power stroke and 12.6(11.6 to 13.6° to the left of the midline during the recovery stroke. Conclusion The photodiode technique greatly underestimates ciliary beat frequency and should not be used to measure ependymal ciliary beat frequency at the temperatures studied. Ciliary beat frequency from the high speed video and photomultiplier techniques cannot be used interchangeably. Ependymal cilia had minimal deviation to

  16. Cannibalistic Predator-Prey Model with Disease in Predator — A Delay Model

    Science.gov (United States)

    Biswas, Santosh; Samanta, Sudip; Chattopadhyay, Joydev

    In this paper, we propose and analyze a cannibalistic predator-prey model with a transmissible disease in the predator population. The disease can be transmitted through contacts with infected individuals as well as the cannibalism of an infected predator. We also consider incubation delay in disease transmission, where the incubation period represents the time in which the infectious agent develops in the host. Local stability analysis of the system around the biologically feasible equilibria is studied. Bifurcation analysis of the system around interior equilibrium is also studied. Applying the normal form theory and central manifold theorem, the direction of Hopf bifurcation, the stability and the period of bifurcating periodic solutions are derived. Under appropriate conditions, the permanence of the system with time delay is proved. Our results suggest that incubation delay destabilizes the system and can produce chaos. We also observe that cannibalism can control disease and population oscillations. Extensive numerical simulations are performed to support our analytical results.

  17. Global Dynamics of a Predator-Prey Model with Stage Structure and Delayed Predator Response

    Directory of Open Access Journals (Sweden)

    Lili Wang

    2013-01-01

    Full Text Available A Holling type II predator-prey model with time delay and stage structure for the predator is investigated. By analyzing the corresponding characteristic equations, the local stability of each of feasible equilibria of the system is discussed. The existence of Hopf bifurcations at the coexistence equilibrium is established. By means of the persistence theory on infinite dimensional systems, it is proven that the system is permanent if the coexistence equilibrium exists. By using Lyapunov functionals and LaSalle’s invariance principle, it is shown that the predator-extinction equilibrium is globally asymptotically stable when the coexistence equilibrium is not feasible, and the sufficient conditions are obtained for the global stability of the coexistence equilibrium.

  18. Predation on exotic zebra mussels by native fishes: Effects on predator and prey

    Science.gov (United States)

    Magoulick, D.D.; Lewis, L.C.

    2002-01-01

    1. Exotic zebra mussels, Dreissena polymorpha, occur in southern U.S. waterways in high densities, but little is known about the interaction between native fish predators and zebra mussels. Previous studies have suggested that exotic zebra mussels are low profitability prey items and native vertebrate predators are unlikely to reduce zebra mussel densities. We tested these hypotheses by observing prey use of fishes, determining energy content of primary prey species of fishes, and conducting predator exclusion experiments in Lake Dardanelle, Arkansas. 2. Zebra mussels were the primary prey eaten by 52.9% of blue catfish, Ictalurus furcatus; 48.2% of freshwater drum, Aplodinotus grunniens; and 100% of adult redear sunfish, Lepomis microlophus. Blue catfish showed distinct seasonal prey shifts, feeding on zebra mussels in summer and shad, Dorosoma spp., during winter. Energy content (joules g-1) of blue catfish prey (threadfin shad, Dorosoma petenense; gizzard shad, D. cepedianum; zebra mussels; and asiatic clams, Corbicula fluminea) showed a significant species by season interaction, but shad were always significantly greater in energy content than bivalves examined as either ash-free dry mass or whole organism dry mass. Fish predators significantly reduced densities of large zebra mussels (>5 mm length) colonising clay tiles in the summers of 1997 and 1998, but predation effects on small zebra mussels (???5 mm length) were less clear. 3. Freshwater drum and redear sunfish process bivalve prey by crushing shells and obtain low amounts of higher-energy food (only the flesh), whereas blue catfish lack a shell-crushing apparatus and ingest large amounts of low-energy food per unit time (bivalves with their shells). Blue catfish appeared to select the abundant zebra mussel over the more energetically rich shad during summer, then shifted to shad during winter when shad experienced temperature-dependent stress and mortality. Native fish predators can suppress adult zebra

  19. Ciliary neurotrophic factor has intrinsic and extrinsic roles in regulating B cell differentiation and bone structure.

    Science.gov (United States)

    Askmyr, Maria; White, Kirby E; Jovic, Tanja; King, Hannah A; Quach, Julie M; Maluenda, Ana C; Baker, Emma K; Smeets, Monique F; Walkley, Carl R; Purton, Louise E

    2015-01-01

    The gp130 receptor and its binding partners play a central role in cytokine signalling. Ciliary neurotrophic factor (CNTF) is one of the cytokines that signals through the gp130 receptor complex. CNTF has previously been shown to be a negative regulator of trabecular bone remodelling and important for motor neuron development. Since haematopoietic cell maintenance and differentiation is dependent on the bone marrow (BM) microenvironment, where cells of the osteoblastic lineage are important regulators, we hypothesised that CNTF may also have important roles in regulating haematopoiesis. Analysis of haematopoietic parameters in male and female Cntf(-/-) mice at 12 and 24 weeks of age revealed altered B lymphopoiesis. Strikingly, the B lymphocyte phenotype differed based on sex, age and also the BM microenvironment in which the B cells develop. When BM cells from wildtype mice were transplanted into Cntf(-/-) mice, there were minimal effects on B lymphopoiesis or bone parameters. However, when Cntf(-/-) BM cells were transplanted into a wildtype BM microenvironment, there were changes in both haematopoiesis and bone parameters. Our data reveal that haematopoietic cell-derived CNTF has roles in regulating BM B cell lymphopoiesis and both trabecular and cortical bone, the latter in a sex-dependent manner. PMID:26487326

  20. Ciliary neurotrophic factor protects striatal neurons against excitotoxicity by enhancing glial glutamate uptake.

    Directory of Open Access Journals (Sweden)

    Corinne Beurrier

    Full Text Available Ciliary neurotrophic factor (CNTF is a potent neuroprotective cytokine in different animal models of glutamate-induced excitotoxicity, although its action mechanisms are still poorly characterized. We tested the hypothesis that an increased function of glial glutamate transporters (GTs could underlie CNTF-mediated neuroprotection. We show that neuronal loss induced by in vivo striatal injection of the excitotoxin quinolinic acid (QA was significantly reduced (by approximately 75% in CNTF-treated animals. In striatal slices, acute QA application dramatically inhibited corticostriatal field potentials (FPs, whose recovery was significantly higher in CNTF rats compared to controls (approximately 40% vs. approximately 7%, confirming an enhanced resistance to excitotoxicity. The GT inhibitor DL-threo-beta-benzyloxyaspartate greatly reduced FP recovery in CNTF rats, supporting the role of GT in CNTF-mediated neuroprotection. Whole-cell patch-clamp recordings from striatal medium spiny neurons showed no alteration of basic properties of striatal glutamatergic transmission in CNTF animals, but the increased effect of a low-affinity competitive glutamate receptor antagonist (gamma-D-glutamylglycine also suggested an enhanced GT function. These data strongly support our hypothesis that CNTF is neuroprotective via an increased function of glial GTs, and further confirms the therapeutic potential of CNTF for the clinical treatment of progressive neurodegenerative diseases involving glutamate overflow.

  1. Brain Ciliary Neurotrophic Factor (CNTF and hypothalamic control of energy homeostasis

    Directory of Open Access Journals (Sweden)

    Vacher Claire-Marie

    2011-09-01

    Full Text Available Cytokines play an important role in energy-balance regulation. Notably leptin, an adipocyte-secreted cytokine, regulates the activity of hypothalamic neurons that are involved in the modulation of appetite. Leptin decreases appetite and stimulates weight loss in rodents. Unfortunately, numerous forms of obesity in humans seem to be resistant to leptin action. The ciliary neurotrophic factor (CNTF is a neurocytokine that belongs to the same family as leptin and that was originally characterized as a neurotrophic factor that promotes the survival of a broad spectrum of neuronal cell types and that enhances neurogenesis in adult rodents. It presents the advantage of stimulating weight loss in humans, despite the leptin resistance. Moreover, the weight loss persists several weeks after the cessation of treatment. Hence, CNTF has been considered as a promising therapeutic tool for the treatment of obesity and has prompted intense research aimed at identifying the cellular and molecular mechanisms underlying its potent anorexigenic properties. It has been found that CNTF shares signaling pathways with leptin and is expressed in the arcuate nucleus (ARC, a key hypothalamic region controlling food intake. Endogenous CNTF may also participate in the control of energy balance. Indeed, its expression in the ARC is inversely correlated to body weight in rats fed a high-sucrose diet. Thus hypothalamic CNTF may act, in some individuals, as a protective factor against weight gain during hypercaloric diet and could account for individual differences in the susceptibility to obesity.

  2. Automated image analysis reveals the dynamic 3-dimensional organization of multi-ciliary arrays

    Directory of Open Access Journals (Sweden)

    Domenico F. Galati

    2016-01-01

    Full Text Available Multi-ciliated cells (MCCs use polarized fields of undulating cilia (ciliary array to produce fluid flow that is essential for many biological processes. Cilia are positioned by microtubule scaffolds called basal bodies (BBs that are arranged within a spatially complex 3-dimensional geometry (3D. Here, we develop a robust and automated computational image analysis routine to quantify 3D BB organization in the ciliate, Tetrahymena thermophila. Using this routine, we generate the first morphologically constrained 3D reconstructions of Tetrahymena cells and elucidate rules that govern the kinetics of MCC organization. We demonstrate the interplay between BB duplication and cell size expansion through the cell cycle. In mutant cells, we identify a potential BB surveillance mechanism that balances large gaps in BB spacing by increasing the frequency of closely spaced BBs in other regions of the cell. Finally, by taking advantage of a mutant predisposed to BB disorganization, we locate the spatial domains that are most prone to disorganization by environmental stimuli. Collectively, our analyses reveal the importance of quantitative image analysis to understand the principles that guide the 3D organization of MCCs.

  3. Stigmasterol Tetracosanoate, a New Stigmasterol Ester from the Egyptian Blepharis ciliaris.

    Science.gov (United States)

    El-Shanawany, M A; Sayed, H M; Ibrahim, S R M; Fayed, M A A

    2015-07-01

    A new stigmasterol ester: stigmasterol tetracosanoate (3), along with 7 compounds: β-sitosterol (1), stigmasterol (2), (2S,3S,4R)-2[(2'R)-2'-(hydroxyeicosanoyl amino) octadecane-1,3,4-triol (4), apigenin (5), β-sitosterol-3-O-β-D-glucopyranoside (6), stigmasterol-3-O-β-D-glucopyranose (7), and apigenin-7-O-β-D-glucopyranoside (8) were isolated from Blepharis ciliaris aerial parts. Compounds 1, 2, and 5-7 are reported here for the first time from the plant and 4 for the first time from the family. GCMS analysis revealed the presence of 45 fatty acids, 53 hydrocarbons, and 24 sterols. The different fractions exhibited mild cytotoxic in brine shrimp assay and anti-hyperglycaemic activities. The EtOAc fraction and TME (total MeOH extract) showed weak anti-malarial activity against P. falciparum. The CHCl3 fraction gave potent -anti-inflammatory activity compared with indomethacin. PMID:24992497

  4. Peripheral sensory processing in mammalian gravity receptors - Observations of ciliary tuft configurations

    Science.gov (United States)

    Ross, Muriel D.; Donovan, Kathleen; Rogers, Charles

    1987-01-01

    Scanning electron microscopy was used to study dynamic polarizations of clustered cells of the anterior part of rat saccular macula and to shed light on the possible roles of two types of hair cells integrated into the same neural circuitry: those with short stereocilia and long kinocilium (ss/lk), and those with long stereocilia and still longer kinocilium (ls/lk). It was found that the ss/lk-type cells could be further subdivided into two types, whereas the ls/lk cells consisted of four major kinds. It was also found that the kinocilium was most often fixed in a recovery stroke position (curved basally, and the upper portion projected back over the tuft) and that the kinocilia were not aligned in parallel in any given part of a macula, even though each cilium pointed in the proper direction relative to the striola line. The possibility of a relationship between the ciliary tuft morphology and the function of the hair cell of which it is a part is discussed.

  5. Circulating levels of ciliary neurotrophic factor in normal pregnancy and preeclampsia

    Directory of Open Access Journals (Sweden)

    Akahori,Yoichiro

    2010-04-01

    Full Text Available

    Ciliary neurotrophic factor (CNTF has been shown to decrease food intake in mouse models of obesity and to improve insulin sensitivity. It is well known that tight regulation of glucose metabolism is essential for successful gestational outcomes (e.g. fetal growth, and that abnormal insulin resistance is associated with preeclampsia (PE. To investigate the possibility that CNTF might be involved in the regulation of insulin resistance during pregnancy, circulating levels of CNTF were assessed in non-pregnant, normal pregnant, postpartum, and pregnant women with PE. Sera from healthy non-pregnant women (n10, pregnant women (n30:1st trimester;n10, 2nd trimester n10;3rd trimester;n10, postpartum women (n10, and patients with PE (n11 were studied with Western blotting. Circulating CNTF was detected by Western blotting, and the levels of CNTF in pregnant women were decreased as compared with those in non-pregnant women, and tended to decrease as pregnancy progressed. A significant decrease was found in PE as compared with normal pregnancy. Circulating CNTF might be associated with physiological and abnormal insulin resistance during pregnancy.

  6. Ciliary body and choroidal melanomas treated by proton beam irradiation. Histopathologic study of eyes

    International Nuclear Information System (INIS)

    Proton beam irradiation resulted in clinical and/or histopathological regression of large ciliary body and choroidal melanomas in three eyes. Enucleations were performed 6 1/2 weeks, five months, and 11 months after irradiation for angle-closure glaucoma from total retinal detachment, increase in retinal detachment, and neovascular glaucoma, respectively. A direct relationship was found between the length of the interval from irradiation to enucleation and the degree of histologic changes. Vascular changes in the tumors included endothelial cell swelling and decreased lumen size, basement membrane thickening, collapse of sinusoidal vessels, and thrombosis of vessels. Although apparently unaltered tumor cells remained, degenerative changes occurred in some melanoma cells, including lipid vacuoles in cytoplasm, pyknotic nuclei, and balloon cell formation. Patchy areas of necrosis and proteinaceous exudate were present. Pigment-laden macrophages were found near tumor vessels and all had a substantial chronic inflammatory infiltrate. The effect of proton beam irradiation on tumor vessels probably plays an important role in uveal melanoma regression

  7. Cascading top-down effects of changing oceanic predator abundances.

    Science.gov (United States)

    Baum, Julia K; Worm, Boris

    2009-07-01

    1. Top-down control can be an important determinant of ecosystem structure and function, but in oceanic ecosystems, where cascading effects of predator depletions, recoveries, and invasions could be significant, such effects had rarely been demonstrated until recently. 2. Here we synthesize the evidence for oceanic top-down control that has emerged over the last decade, focusing on large, high trophic-level predators inhabiting continental shelves, seas, and the open ocean. 3. In these ecosystems, where controlled manipulations are largely infeasible, 'pseudo-experimental' analyses of predator-prey interactions that treat independent predator populations as 'replicates', and temporal or spatial contrasts in predator populations and climate as 'treatments', are increasingly employed to help disentangle predator effects from environmental variation and noise. 4. Substantial reductions in marine mammals, sharks, and piscivorous fishes have led to mesopredator and invertebrate predator increases. Conversely, abundant oceanic predators have suppressed prey abundances. Predation has also inhibited recovery of depleted species, sometimes through predator-prey role reversals. Trophic cascades have been initiated by oceanic predators linking to neritic food webs, but seem inconsistent in the pelagic realm with effects often attenuating at plankton. 5. Top-down control is not uniformly strong in the ocean, and appears contingent on the intensity and nature of perturbations to predator abundances. Predator diversity may dampen cascading effects except where nonselective fisheries deplete entire predator functional groups. In other cases, simultaneous exploitation of predator and prey can inhibit prey responses. Explicit consideration of anthropogenic modifications to oceanic foodwebs should help inform predictions about trophic control. 6. Synthesis and applications. Oceanic top-down control can have important socio-economic, conservation, and management implications as

  8. On multi-team predator-prey models

    International Nuclear Information System (INIS)

    Many creatures form teams. This has, at least, two main advantages: the first is the improvement in foraging, since looking for food in a team is more efficient than doing it alone. The second is that living in a team reduces predation risk due to early spotting of predators and that existing in a team gives a higher probability that the predator will attack another member of the team. In this paper models are given where two teams of predators interact with two teams of preys. The teams of each group (predators or preys) help each other. In this paper we propose three different versions of the multi-team predator prey model. We study the equilibrium solutions, the conditions of their local asymptotic stability, persistence and the global stability of the solution of one of the models. Some numerical simulations are done. (author)

  9. Revisited Hastings and Powell model with omnivory and predator switching

    International Nuclear Information System (INIS)

    The effect of omnivory in predator–prey system is debatable regarding its stabilizing or destabilizing characteristics. Earlier theoretical studies predict that omnivory is stabilizing or destabilizing depending on the condition of the system. The effect of omnivory in the food chain system is not yet properly understood. In the present paper, we study the effect of omnivory in a tri-trophic food chain system on the famous Hastings and Powell model. Omnivory enhances the chance of predator switching between prey and middle predator. The novelty of this paper is to study the effect of predator switching of the top predator which is omnivorous in nature. Our results suggest that in the absence of switching, an increase of omnivory stabilizes the system from chaotic dynamics, however, if we further increase the strength of omnivory, the system becomes unstable and middle predator goes to extinction. It is also observed that the predator switching enhance the stability and persistence of all populations

  10. Weed seed predation in organic and conventional fields

    DEFF Research Database (Denmark)

    Navntoft, Søren; Wratten, S.D.; Kristensen, Kristian;

    2009-01-01

    Enhanced biological control of weed seeds may improve sustainability of agricultural production. Biological control due to seed predation may be higher in organic fields because organic production generally supports more seed predators. To investigate such a difference, weed seed predation was...... at distances of 0, 3, 9 and 50 m from the field edge. The weed seeds were placed at the above distances on small dishes of finely sieved soil and sunk into the ground. Removal rates were recorded after 48 h. Seed predators were identified using video recording at an organically grown husbandry unit...... losses at organic field edges. Overall, there was no consistent effect of distance from the field edge. Vegetation had a significant influence on the predation rates, with maximum rates at a medium-dense plant cover. Based on the video images, birds were the most important seed predators. The higher weed...

  11. The narrow range of perceived predation: a 19 group study

    Directory of Open Access Journals (Sweden)

    Olivier Mesly

    2013-05-01

    Full Text Available This paper rests largely on the works of Mesly (1999 to 2012. It argues that the phenomenon of perceived predation as a functional behavioural phenomenon is subjected to certain limits, a finding based on studies performed on 19 different groups spread over a four-year span. It also finds a constant of k = 1.3 which reflects the invariant nature of perceived predation. These findings add to the theory of financial predation which stipulates that financial predators operate below the limits of detection pertaining to their customers (and market regulators. They are experts at minimizing the perception that clients could have that they are after their money, causing them financial harm, by surprise (perceived predation. Understanding the narrow range in which financial predators operate is setting the grounds to offer better protection to investors and to implementing better control and punitive measures.

  12. Surgical Sterilization of Coyotes to Reduce Predation on Pronghorn Fawns

    OpenAIRE

    Seidler, Renee

    2009-01-01

    Coyote (Canis latrans) predation accounts for the majority of neonatal pronghorn (Antilocapra americana) mortality in many areas and may influence local population declines. Current techniques used to manage coyote predation on wildlife species generally focus on lethal control methods. However, these methods may be controversial to the general public. Coyote sterilization is an alternative predation control method which is more acceptable to the public and has been shown to be effective in r...

  13. Survival of the Stillest: Predator Avoidance in Shark Embryos

    OpenAIRE

    Kempster, Ryan M.; Hart, Nathan S.; Collin, Shaun P.

    2013-01-01

    Sharks use highly sensitive electroreceptors to detect the electric fields emitted by potential prey. However, it is not known whether prey animals are able to modulate their own bioelectrical signals to reduce predation risk. Here, we show that some shark (Chiloscyllium punctatum) embryos can detect predator-mimicking electric fields and respond by ceasing their respiratory gill movements. Despite being confined to the small space within the egg case, where they are vulnerable to predators, ...

  14. Does avian conspicuous colouration increase or reduce predation risk?

    OpenAIRE

    Ruiz-Rodríguez, M.; Avilés, Jesús M; Cuervo, José Javier; Parejo, D.; Ruano, F.; Zamora-Muñoz, G.; Sergio, Fabrizio; López-Jiménez, Lidia; Tanferna, Alessandro; Martín-Vivaldi, Manuel

    2013-01-01

    Animals often announce their unprofitability to predators through conspicuous coloured signals. Here we tested whether the apparently conspicuous colour designs of the four European Coraciiformes and Upupiformes species may have evolved as aposematic signals, or whether instead they imply a cost in terms of predation risk. Because previous studies suggested that these species are unpalatable, we hypothesized that predators could avoid targeting them based on their colours. An experiment was p...

  15. Nest predation and the evolution of nestling begging calls

    OpenAIRE

    Briskie, J. V.; Martin, P R; Martin, T E

    1999-01-01

    Begging by nestling birds can be conspicuous and loud. Such displays are thought to function in signalling nestling condition and securing parental care, but they also may inadvertently attract the attention of predators. We compared the structure of nestling begging calls to the risk of predation among 24 species of birds breeding in a forest community in central Arizona. After controlling for body size and phylogeny, we found that species subject to greater nest predation had calls with hig...

  16. Effectiveness of predator odors as gray squirrel repellents

    OpenAIRE

    Rosell, Frank

    2001-01-01

    The ability of gray squirrels (Sciurus carolinensis) to discriminate between different predator odors and the use of predator odors to deter gray squirrels from foraging on plants have not been previously investigated. To test the hypothesis that predator scent decreases foraging, I investigated the effect of such scent on consumption of butternuts (Juglans cinerea) in the field. Results showed that (i) red fox (Vulpes vulpes) scent was significantly more effective than either a control or hu...

  17. Does afforestation increase bird nest predation risk in surrounding farmland?

    OpenAIRE

    Reino, Luis; Porto, Miguel; Morgado, Rui; Carvalho, Filipe; Mira, António; Beja, Pedro

    2010-01-01

    Afforestation of agricultural land is increasingly used to deliver environmental benefits, but their effects on biodiversity remain poorly understood. This paper tests the hypothesis that afforestation changes predation processes in surrounding farmland, examining how the characteristics and landscape context of forest plantations affect predator (birds and mammalian carnivores) and key prey (rabbits and hares) abundances, and bird nest predation rates in Iberian cereal-steppes. Lagomorp...

  18. Population dynamics of intraguild predation in a lattice gas system.

    Science.gov (United States)

    Wang, Yuanshi; Wu, Hong

    2015-01-01

    In the system of intraguild predation (IGP) we are concerned with, species that are in a predator-prey relationship, also compete for shared resources (space or food). While several models have been established to characterize IGP, mechanisms by which IG prey and IG predator can coexist in IGP systems with spatial competition, have not been shown. This paper considers an IGP model, which is derived from reactions on lattice and has a form similar to that of Lotka-Volterra equations. Dynamics of the model demonstrate properties of IGP and mechanisms by which the IGP leads to coexistence of species and occurrence of alternative states. Intermediate predation is shown to lead to persistence of the predator, while extremely big predation can lead to extinction of one/both species and extremely small predation can lead to extinction of the predator. Numerical computations confirm and extend our results. While empirical observations typically exhibit coexistence of IG predator and IG prey, theoretical analysis in this work demonstrates exact conditions under which this coexistence can occur. PMID:25447811

  19. Top predators negate the effect of mesopredators on prey physiology.

    Science.gov (United States)

    Palacios, Maria M; Killen, Shaun S; Nadler, Lauren E; White, James R; McCormick, Mark I

    2016-07-01

    Predation theory and empirical evidence suggest that top predators benefit the survival of resource prey through the suppression of mesopredators. However, whether such behavioural suppression can also affect the physiology of resource prey has yet to be examined. Using a three-tier reef fish food web and intermittent-flow respirometry, our study examined changes in the metabolic rate of resource prey exposed to combinations of mesopredator and top predator cues. Under experimental conditions, the mesopredator (dottyback, Pseudochromis fuscus) continuously foraged and attacked resource prey (juveniles of the damselfish Pomacentrus amboinensis) triggering an increase in prey O2 uptake by 38 ± 12·9% (mean ± SE). The visual stimulus of a top predator (coral trout, Plectropomus leopardus) restricted the foraging activity of the mesopredator, indirectly allowing resource prey to minimize stress and maintain routine O2 uptake. Although not as strong as the effect of the top predator, the sight of a large non-predator species (thicklip wrasse, Hemigymnus melapterus) also reduced the impact of the mesopredator on prey metabolic rate. We conclude that lower trophic-level species can benefit physiologically from the presence of top predators through the behavioural suppression that top predators impose on mesopredators. By minimizing the energy spent on mesopredator avoidance and the associated stress response to mesopredator attacks, prey may be able to invest more energy in foraging and growth, highlighting the importance of the indirect, non-consumptive effects of top predators in marine food webs. PMID:27113316

  20. Ecosystem context and historical contingency in apex predator recoveries.

    Science.gov (United States)

    Stier, Adrian C; Samhouri, Jameal F; Novak, Mark; Marshall, Kristin N; Ward, Eric J; Holt, Robert D; Levin, Phillip S

    2016-05-01

    Habitat loss, overexploitation, and numerous other stressors have caused global declines in apex predators. This "trophic downgrading" has generated widespread concern because of the fundamental role that apex predators can play in ecosystem functioning, disease regulation, and biodiversity maintenance. In attempts to combat declines, managers have conducted reintroductions, imposed stricter harvest regulations, and implemented protected areas. We suggest that full recovery of viable apex predator populations is currently the exception rather than the rule. We argue that, in addition to well-known considerations, such as continued exploitation and slow life histories, there are several underappreciated factors that complicate predator recoveries. These factors include three challenges. First, a priori identification of the suite of trophic interactions, such as resource limitation and competition that will influence recovery can be difficult. Second, defining and accomplishing predator recovery in the context of a dynamic ecosystem requires an appreciation of the timing of recovery, which can determine the relative density of apex predators and other predators and therefore affect competitive outcomes. Third, successful recovery programs require designing adaptive sequences of management strategies that embrace key environmental and species interactions as they emerge. Consideration of recent research on food web modules, alternative stable states, and community assembly offer important insights for predator recovery efforts and restoration ecology more generally. Foremost among these is the importance of a social-ecological perspective in facilitating a long-lasting predator restoration while avoiding unintended consequences. PMID:27386535

  1. Assessment of predation risk through referential communication in incubating birds

    Science.gov (United States)

    Suzuki, Toshitaka N.

    2015-05-01

    Parents of many bird species produce alarm calls when they approach and deter a nest predator in order to defend their offspring. Alarm calls have been shown to warn nestlings about predatory threats, but parents also face a similar risk of predation when incubating eggs in their nests. Here, I show that incubating female Japanese great tits, Parus minor, assess predation risk by conspecific alarm calls given outside the nest cavity. Tits produce acoustically discrete alarm calls for different nest predators: “jar” calls for snakes and “chicka” calls for other predators such as crows and martens. Playback experiments revealed that incubating females responded to “jar” calls by leaving their nest, whereas they responded to “chicka” calls by looking out of the nest entrance. Since snakes invade the nest cavity, escaping from the nest helps females avoid snake predation. In contrast, “chicka” calls are used for a variety of predator types, and therefore, looking out of the nest entrance helps females gather information about the type and location of approaching predators. These results show that incubating females derive information about predator type from different types of alarm calls, providing a novel example of functionally referential communication.

  2. Discriminative predation: Simultaneous and sequential encounter experiments

    Institute of Scientific and Technical Information of China (English)

    C.D.BEATTY; D.W.FRANKS

    2012-01-01

    There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences.For example,the objects that require discrimination may be edible versus defended prey,predators versus non-predators,or mates of varying quality.Working from the premise that there are situations in which discrimination may be more or less successful,we hypothesized that individuals find it more difficult to distinguish between stimuli when they encounter them sequentially rather than simultaneously.Our study has wide biological and psychological implications from the perspective of signal perception,signal evolution,and discrimination,and could apply to any system where individuals are making relative judgments or choices between two or more stimuli or signals.While this is a general principle that might seem intuitive,it has not been experimentally tested in this context,and is often not considered in the design of models or experiments,or in the interpretation of a wide range of studies.Our study is different from previous studies in psychology in that a) the level of similarity of stimuli are gradually varied to obtain selection gradients,and b) we discuss the implications of our study for specific areas in ecology,such as the level of perfection of mimicry in predator-prey systems.Our experiments provide evidence that it is indeed more difficult to distinguish between stimuli - and to learn to distinguish between stimuli - when they are encountered sequentially rather than simultaneously,even if the intervening time interval is short.

  3. Discriminative predation: Simultaneous and sequential encounter experiments

    Directory of Open Access Journals (Sweden)

    C. D. BEATTY, D.W.FRANKS

    2012-08-01

    Full Text Available There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences. For example, the objects that require discrimination may be edible versus defended prey, predators versus non-predators, or mates of varying quality. Working from the premise that there are situations in which discrimination may be more or less successful, we hypothesized that individuals find it more difficult to distinguish between stimuli when they encounter them sequentially rather than simultaneously. Our study has wide biological and psychological implications from the perspective of signal perception, signal evolution, and discrimination, and could apply to any system where individuals are making relative judgments or choices between two or more stimuli or signals. While this is a general principle that might seem intuitive, it has not been experimentally tested in this context, and is often not considered in the design of models or experiments, or in the interpretation of a wide range of studies. Our study is different from previous studies in psychology in that a the level of similarity of stimuli are gradually varied to obtain selection gradients, and b we discuss the implications of our study for specific areas in ecology, such as the level of perfection of mimicry in predator-prey systems. Our experiments provide evidence that it is indeed more difficult to distinguish between stimuli – and to learn to distinguish between stimuli – when they are encountered sequentially rather than simultaneously, even if the intervening time interval is short [Current Zoology 58 (4: 649–657, 2012].

  4. Wave propagation in predator-prey systems

    Science.gov (United States)

    Fu, Sheng-Chen; Tsai, Je-Chiang

    2015-12-01

    In this paper, we study a class of predator-prey systems of reaction-diffusion type. Specifically, we are interested in the dynamical behaviour for the solution with the initial distribution where the prey species is at the level of the carrying capacity, and the density of the predator species has compact support, or exponentially small tails near x=+/- ∞ . Numerical evidence suggests that this will lead to the formation of a pair of diverging waves propagating outwards from the initial zone. Motivated by this phenomenon, we establish the existence of a family of travelling waves with the minimum speed. Unlike the previous studies, we do not use the shooting argument to show this. Instead, we apply an iteration process based on Berestycki et al 2005 (Math Comput. Modelling 50 1385-93) to construct a set of super/sub-solutions. Since the underlying system does not enjoy the comparison principle, such a set of super/sub-solutions is not based on travelling waves, and in fact the super/sub-solutions depend on each other. With the aid of the set of super/sub-solutions, we can construct the solution of the truncated problem on the finite interval, which, via the limiting argument, can in turn generate the wave solution. There are several advantages to this approach. First, it can remove the technical assumptions on the diffusivities of the species in the existing literature. Second, this approach is of PDE type, and hence it can shed some light on the spreading phenomenon indicated by numerical simulation. In fact, we can compute the spreading speed of the predator species for a class of biologically acceptable initial distributions. Third, this approach might be applied to the study of waves in non-cooperative systems (i.e. a system without a comparison principle).

  5. Statistical evidence of predation by theropods

    Science.gov (United States)

    Lee, Scott

    2011-03-01

    Dinosaurs hold a great fascination for everyone and provide an interesting venue for teaching many elementary concepts of kinematics. Dinosaur trackways provide interesting information about the locomotion of these extinct animals. A statistical analysis of the known trackways made by theropods (carnivorous dinosaurs) shows that they usually moved by walking with an average speed of 2.4 +/- 1.5 m/s. Fast running, determined by the relative stride length greater than 3, is observed in about 10% of the trackways, with speeds on the order of 10 m/s. These trackways are believed to have been formed during predation.

  6. A predator-prey system with stage-structure for predator and nonlocal delay

    DEFF Research Database (Denmark)

    Lin, Z.G.; Pedersen, Michael; Zhang, Lai

    This paper deals with the behavior of solutions to the reaction-diffusion system under homogeneous Neumann boundary condition, which describes a prey-predator model with nonlocal delay. Sufficient conditions for the global stability of each equilibrium are derived by the Lyapunov functional and the...

  7. Ontogenetic specialism in predators with multiple niche shifts prevents predator population recovery and establishment

    NARCIS (Netherlands)

    A. van Leeuwen; M. Huss; A. Gårdmark; A.M. de Roos

    2014-01-01

    The effects of ontogenetic niche shifts on community structure and dynamics are underexplored, despite the occurrence of such shifts in the majority of animal species. We studied the form of niche shifts in a predator that exhibits multiple ontogenetic niche shifts, and analyzed how this life histor

  8. Parental investment decisions in response to ambient nest-predation risk versus actual predation on the prior nest

    Science.gov (United States)

    Chalfoun, A.D.; Martin, T.E.

    2010-01-01

    Theory predicts that parents should invest less in dependent offspring with lower reproductive value, such as those with a high risk of predation. Moreover, high predation risk can favor reduced parental activity when such activity attracts nest predators. Yet, the ability of parents to assess ambient nest-predation risk and respond adaptively remains unclear, especially where nest-predator assemblages are diverse and potentially difficult to assess. We tested whether variation in parental investment by a multi-brooded songbird (Brewer's Sparrow, Spizella breweri) in an environment (sagebrush steppe) with diverse predators was predicted by ambient nest-predation risk or direct experience with nest predation. Variation among eight sites in ambient nest-predation risk, assayed by daily probabilities of nest predation, was largely uncorrelated across four years. In this system risk may therefore be unpredictable, and aspects of parental investment (clutch size, egg mass, incubation rhythms, nestling-feeding rates) were not related to ambient risk. Moreover, investment at first nests that were successful did not differ from that at nests that were depredated, suggesting parents could not assess and respond to territorylevel nest-predation risk. However, parents whose nests were depredated reduced clutch sizes and activity at nests attempted later in the season by increasing the length of incubation shifts (on-bouts) and recesses (off-bouts) and decreasing trips to feed nestlings. In this unpredictable environment parent birds may therefore lack sufficient cues of ambient risk on which to base their investment decisions and instead rely on direct experience with nest predation to inform at least some of their decisions. ?? 2010 The Cooper Ornithological Society.

  9. Factors influencing predation on juvenile ungulates and natural selection implications

    Directory of Open Access Journals (Sweden)

    S. M. Barber-Meyer

    2008-06-01

    Full Text Available Juvenile ungulates are generally more vulnerable to predation than are adult ungulates other than senescent individuals, not only because of their relative youth, fragility, and inexperience, but also because of congenital factors. Linnell et al.’s (Wildl. Biol. 1: 209-223 extensive review of predation on juvenile ungulates concluded that research was needed to determine the predisposition of these juveniles to predation. Since then, various characteristics that potentially predispose juvenile ungulates have emerged including blood characteristics, morphometric and other condition factors, and other factors such as birth period, the mother’s experience, and spatial and habitat aspects. To the extent that any of the physical or behavioral traits possessed by juvenile ungulates have a genetic or heritable and partly independent epigenetic component that predisposes them to predation, predators may play an important role in their natural selection. We review the possible influence of these characteristics on predisposing juvenile ungulates to predation and discuss natural selection implications and potential selection mechanisms. Although juvenile ungulates as a class are likely more vulnerable to predation than all but senescent adults, our review presents studies indicating that juveniles with certain tendencies or traits are killed more often than others. This finding suggests that successful predation on juveniles is more selective than is often assumed. Because we are unable to control for (or in some cases even measure the myriad of other possible vulnerabilities such as differences in sensory abilities, intelligence, hiding abilities, tendency to travel, etc., finding selective predation based on the relatively few differences we can measure is noteworthy and points to the significant role that predation on juveniles has in the natural selection of ungulates. Future research should compare characteristics, especially those known to

  10. Predators and predation rates of skylark Alauda arvensis and woodlark Lullula arborea nests in a semi-natural area in the Netherlands

    NARCIS (Netherlands)

    Praus, Libor; Hegemann, Arne; Tieleman, B. Irene; Weidinger, Karel

    2014-01-01

    Predation is a major cause of breeding failure in bird species with open nests. Although many studies have investigated nest predation rates, direct identification of nest predators is sporadic, especially in (semi-)natural habitats. We quantified nest success and identified nest predators in a popu

  11. The role of hair cells, cilia and ciliary motility in otolith formation in the zebrafish otic vesicle.

    Science.gov (United States)

    Stooke-Vaughan, Georgina A; Huang, Peng; Hammond, Katherine L; Schier, Alexander F; Whitfield, Tanya T

    2012-05-01

    Otoliths are biomineralised structures required for the sensation of gravity, linear acceleration and sound in the zebrafish ear. Otolith precursor particles, initially distributed throughout the otic vesicle lumen, become tethered to the tips of hair cell kinocilia (tether cilia) at the otic vesicle poles, forming two otoliths. We have used high-speed video microscopy to investigate the role of cilia and ciliary motility in otolith formation. In wild-type ears, groups of motile cilia are present at the otic vesicle poles, surrounding the immotile tether cilia. A few motile cilia are also found on the medial wall, but most cilia (92-98%) in the otic vesicle are immotile. In mutants with defective cilia (iguana) or ciliary motility (lrrc50), otoliths are frequently ectopic, untethered or fused. Nevertheless, neither cilia nor ciliary motility are absolutely required for otolith tethering: a mutant that lacks cilia completely (MZovl) is still capable of tethering otoliths at the otic vesicle poles. In embryos with attenuated Notch signalling [mindbomb mutant or Su(H) morphant], supernumerary hair cells develop and otolith precursor particles bind to the tips of all kinocilia, or bind directly to the hair cells' apical surface if cilia are absent [MZovl injected with a Su(H)1+2 morpholino]. However, if the first hair cells are missing (atoh1b morphant), otolith formation is severely disrupted and delayed. Our data support a model in which hair cells produce an otolith precursor-binding factor, normally localised to tether cell kinocilia. We also show that embryonic movement plays a minor role in the formation of normal otoliths. PMID:22461562

  12. Immersed boundary-lattice Boltzmann method for simulation of muco-ciliary transport: effect of mucus depth at various amounts of cilia beat frequency

    Science.gov (United States)

    Shahmardan, M. M.; Sedaghat, M. H.; Norouzi, M.; Nazari, M.

    2015-12-01

    Numerical simulation based on immersed boundary-lattice Boltzmann method has been employed to study 2D muco-ciliary transport problem. The periciliary liquid (PCL) and mucus layers in this study are considered as the Newtonian and viscoelastic fluid respectively. An Oldroyd-B model is used as the constitutive equations of mucus layer. To simulate accurate effects of the cilia and PCL-mucus interface on the fluid, immersed boundary method is used. Numerical simulations have been performed to investigate the effects of mucus depth on the muco-ciliary clearance at various values of cilia beat frequencies. Our results show that, by increasing mucus depth, which results from air pollution and smoking, mean mucus velocity decreases. But it can be completely modified by increasing cilia beat frequency and the cilia beat frequency has great effect on the muco-ciliary clearance.

  13. The Cytokine Ciliary Neurotrophic Factor (CNTF) Activates Hypothalamic Urocortin-Expressing Neurons Both In Vitro and In Vivo

    OpenAIRE

    Purser, Matthew J.; Dalvi, Prasad S.; Wang, Zi C.; Belsham, Denise D.

    2013-01-01

    Ciliary neurotrophic factor (CNTF) induces neurogenesis, reduces feeding, and induces weight loss. However, the central mechanisms by which CNTF acts are vague. We employed the mHypoE-20/2 line that endogenously expresses the CNTF receptor to examine the direct effects of CNTF on mRNA levels of urocortin-1, urocortin-2, agouti-related peptide, brain-derived neurotrophic factor, and neurotensin. We found that treatment of 10 ng/ml CNTF significantly increased only urocortin-1 mRNA by 1.84-fold...

  14. Ciliary neurotrophic factor-treated astrocyte-conditioned medium increases the intracellular free calcium concentration in rat cortical neurons

    OpenAIRE

    SUN, MEIQUN; Liu, Hongli; MIN, SHENGPING; Wang, Hongtao; Wang, Xiaojing

    2016-01-01

    Ciliary neurotrophic factor (CNTF) is involved in the activation of astrocytes. A previous study showed that CNTF-treated astrocyte-conditioned medium (CNTF-ACM) contributed to the increase of the calcium current and the elevation of corresponding ion channels in cortical neurons. On this basis, it is reasonable to assume that CNTF-ACM may increase the intracellular free calcium concentration ([Ca2+]i) in neurons. In the present study, the effects of CNTF-ACM on [Ca2+]i in rat cortical neuron...

  15. Suppression of IκBα increases the expression of matrix metalloproteinase-2 in human ciliary muscle cells

    OpenAIRE

    Lan, Yu-Qing; Zhang, Chi; Xiao, Jian-Hui; Zhuo, Ye-hong; Guo, Hui; Peng, Wei; Ge, Jian

    2009-01-01

    Purpose An increase of matrix metalloproteinase-2 (MMP-2) has been found to improve outflow through the uveoscleral pathway. This experiment was designed to test whether reduction of inhibitor of nuclear factor kappa B alpha (IκBα) levels could enhance MMP-2 expression in human ciliary muscle (HCM) cells in vitro. Methods The small interfering RNA (siRNA) targeting inhibitor of nuclear factor kappa B (IκBα) was transfected into HCM cells. The mRNA and protein levels of IκBα, nuclear factor-ka...

  16. Sleeping birds do not respond to predator odour.

    Directory of Open Access Journals (Sweden)

    Luisa Amo

    Full Text Available BACKGROUND: During sleep animals are relatively unresponsive and unaware of their environment, and therefore, more exposed to predation risk than alert and awake animals. This vulnerability might influence when, where and how animals sleep depending on the risk of predation perceived before going to sleep. Less clear is whether animals remain sensitive to predation cues when already asleep. METHODOLOGY/PRINCIPAL FINDINGS: We experimentally tested whether great tits are able to detect the chemical cues of a common nocturnal predator while sleeping. We predicted that birds exposed to the scent of a mammalian predator (mustelid twice during the night would not go into torpor (which reduces their vigilance and hence would not reduce their body temperature as much as control birds, exposed to the scent of another mammal that does not represent a danger for the birds (rabbit. As a consequence of the higher body temperature birds exposed to the scent of a predator are predicted to have a higher resting metabolic rate (RMR and to lose more body mass. In the experiment, all birds decreased their body temperature during the night, but we did not find any influence of the treatment on body temperature, RMR, or body mass. CONCLUSIONS/SIGNIFICANCE: Our results suggest that birds are not able to detect predator chemical cues while sleeping. As a consequence, antipredatory strategies taken before sleep, such as roosting sites inspection, may be crucial to cope with the vulnerability to predation risk while sleeping.

  17. Influence of edge on predator prey distribution and abundance

    Science.gov (United States)

    Ferguson, Steven H.

    2004-03-01

    I investigated the effect of spatial configuration on distribution and abundance of invertebrate trophic groups by counting soil arthropods under boxes (21 × 9.5 cm) arranged in six different patterns that varied in the amount of edge (137-305 cm). I predicted fewer individuals from the consumer trophic group (Collembola) in box groups with greater amount of edge. This prediction was based on the assumption that predators (mites, ants, spiders, centipedes) select edge during foraging and thereby reduce abundance of the less mobile consumer group under box patterns with greater edge. Consumer abundance (Collembola) was not correlated with amount of edge. Among the predator groups, mite, ant and centipede abundance related to the amount of edge of box groups. However, in contrast to predictions, abundance of these predators was negatively correlated with amount of edge in box patterns. All Collembola predators, with the exception of ants, were less clumped in distribution than Collembola. The results are inconsistent with the view that predators used box edges to predate the less mobile consumer trophic group. Alternative explanations for the spatial patterns other than predator-prey relations include (1) a negative relationship between edge and moisture, (2) a positive relationship between edge and detritus decomposition (i.e. mycelium as food for the consumer group), and (3) a negative relationship between edge and the interstices between adjacent boxes. Landscape patterns likely affect microclimate, food, and predator-prey relations and, therefore, future experimental designs need to control these factors individually to distinguish among alternative hypotheses.

  18. Disentangling mite predator-prey relationships by multiplex PCR.

    Science.gov (United States)

    Pérez-Sayas, Consuelo; Pina, Tatiana; Gómez-Martínez, María A; Camañes, Gemma; Ibáñez-Gual, María V; Jaques, Josep A; Hurtado, Mónica A

    2015-11-01

    Gut content analysis using molecular techniques can help elucidate predator-prey relationships in situations in which other methodologies are not feasible, such as in the case of trophic interactions between minute species such as mites. We designed species-specific primers for a mite community occurring in Spanish citrus orchards comprising two herbivores, the Tetranychidae Tetranychus urticae and Panonychus citri, and six predatory mites belonging to the Phytoseiidae family; these predatory mites are considered to be these herbivores' main biological control agents. These primers were successfully multiplexed in a single PCR to test the range of predators feeding on each of the two prey species. We estimated prey DNA detectability success over time (DS50), which depended on the predator-prey combination and ranged from 0.2 to 18 h. These values were further used to weight prey detection in field samples to disentangle the predatory role played by the most abundant predators (i.e. Euseius stipulatus and Phytoseiulus persimilis). The corrected predation value for E. stipulatus was significantly higher than for P. persimilis. However, because this 1.5-fold difference was less than that observed regarding their sevenfold difference in abundance, we conclude that P. persimilis is the most effective predator in the system; it preyed on tetranychids almost five times more frequently than E. stipulatus did. The present results demonstrate that molecular tools are appropriate to unravel predator-prey interactions in tiny species such as mites, which include important agricultural pests and their predators. PMID:25824504

  19. Ecology: The Upside-Down World of Coral Reef Predators.

    Science.gov (United States)

    Simpfendorfer, Colin A; Heupel, Michelle R

    2016-08-01

    Examination of a large aggregation of sharks demonstrates that trophic pyramids with greater amounts of high-level predators than prey can occur on coral reefs. This is possible because the high-level predators obtain food from sources outside their home location. PMID:27505241

  20. Food aquisition and predator avoidance in a Neotropical rodent

    NARCIS (Netherlands)

    Suselbeek, L.; Emsens, W.J.; Hirsch, B.T.; Kays, R.; Rowcliffe, J.M.; Zamore-Gutierrez, V.; Jansen, P.A.

    2014-01-01

    Foraging activity in animals reflects a compromise between acquiring food and avoiding predation. The Risk Allocation Hypothesis predicts that prey animals optimize this balance by concentrating their foraging activity at times of relatively low predation risk, as much as their energy status permits

  1. Cross-continental differences in patterns of predation: will naive moose in Scandinavia ever learn?

    OpenAIRE

    Sand, Håkan; Wikenros, Camilla; Wabakken, Petter; Liberg, Olof

    2006-01-01

    Predation has been recognized as a major selective force in the evolution of behavioural characteristics of mammals. As a consequence of local predator extinction, prey may lose knowledge about natural predators but usually express behavioural adjustments after return of predators. Human harvest may replace natural predation but prey selection may differ from that of natural predators leading to a change in the behavioural response of prey. We show that hunting success (HS) of re-colonizing w...

  2. Gregarious nesting - An anti-predator response in laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch

    2012-01-01

    in nesting strategy. The aim of the present experiment was to investigate whether gregarious nesting due to behavioural flexibility in nesting strategy is an anti-predator response. Twelve groups of 14–15 Isa Warren hens age 44 weeks were housed in pens each containing three adjacent roll-out nest...... behaviour displayed by feral hens that isolate themselves from the flock during nesting activities. What motivates laying hens to perform gregarious nesting is unknown. One possibility is that gregarious nesting is an anti-predator response to the risk of nest predation emerging from behavioural flexibility...... predator period (P<0.01). The general distribution of hens in the pens did not change between periods (P>0.05). In conclusion, evidence was found for the proposed hypothesis that gregarious nesting is an anti-predator response....

  3. Environmental versus demographic variability in stochastic predator-prey models

    Science.gov (United States)

    Dobramysl, U.; Täuber, U. C.

    2013-10-01

    In contrast to the neutral population cycles of the deterministic mean-field Lotka-Volterra rate equations, including spatial structure and stochastic noise in models for predator-prey interactions yields complex spatio-temporal structures associated with long-lived erratic population oscillations. Environmental variability in the form of quenched spatial randomness in the predation rates results in more localized activity patches. Our previous study showed that population fluctuations in rare favorable regions in turn cause a remarkable increase in the asymptotic densities of both predators and prey. Very intriguing features are found when variable interaction rates are affixed to individual particles rather than lattice sites. Stochastic dynamics with demographic variability in conjunction with inheritable predation efficiencies generate non-trivial time evolution for the predation rate distributions, yet with overall essentially neutral optimization.

  4. Compensatory feeding following a predator removal program : detection and mechanisms

    International Nuclear Information System (INIS)

    Predator removal is one of the oldest management tools in existence, with evidence that ancient Greeks used a bounty reward for wolves over 3,000 years ago (Anonymous 1964). Efforts to control predators on fish have been documented in scientific journals for at least 60 years (Eschmeyer 1937; Lagler 1939; Foerster and Ricker 1941; Smith and Swingle 1941; Jeppson and Platts 1959), and has likely been attempted for much longer. Complete eradication of a target species from a body of water has rarely been the objective of predator removal programs, which instead have attempted to eliminate predators from specific areas, to reduce the density or standing stock of predators, or to kill the largest individuals in the population (Meronek et al. 1996). In evaluating management programs that remove only part of a predator population, the compensatory response(s) of the remaining predators must be considered. Some potential compensatory responses by remaining individuals include increased reproductive output, increased growth rate, or increased consumption of certain prey species (Jude et al. 1987). If compensation by predators that remain in the system following a removal effort occurs, it may reduce the effectiveness of the predator control program. Northern pike-minnow Ptychocheilus oregonensis (formerly called northern squawfish) consume juvenile salmon in rivers, lakes, and reservoirs in British Columbia, Washington, Idaho, Oregon, and California. Northern pikeminnow have been estimated to consume about 11% of all juvenile salmon that migrate through John Day Reservoir on the Columbia River (Rieman et al. 1991). Modeling studies suggested that removal of 20% of the northern pikeminnow population in John Day Reservoir would result in a 50% decrease in predation-related mortality of juvenile salmon migrating through this reach (Beamesderfer et al. 1991). Since the early 1940's, other programs have been implemented to remove northern pikeminnow, with hopes of improving the

  5. Stationary distribution and periodic solution for stochastic predator-prey systems with nonlinear predator harvesting

    Science.gov (United States)

    Zuo, Wenjie; Jiang, Daqing

    2016-07-01

    In this paper, we investigate the dynamics of the stochastic autonomous and non-autonomous predator-prey systems with nonlinear predator harvesting respectively. For the autonomous system, we first give the existence of the global positive solution. Then, in the case of persistence, we prove that there exists a unique stationary distribution and it has ergodicity by constructing a suitable Lyapunov function. The result shows that, the relatively weaker white noise will strengthen the stability of the system, but the stronger white noise will result in the extinction of one or two species. Particularly, for the non-autonomous periodic system, we show that there exists at least one nontrivial positive periodic solution according to the theory of Khasminskii. Finally, numerical simulations illustrate our theoretical results.

  6. Active predation by Greenland shark Somniosus microcephalus

    DEFF Research Database (Denmark)

    Nielsen, Julius; hedeholm, Rasmus; Simon, Malene;

    2013-01-01

    Dansk Havforskermøde 2013 Julius Nielsen, Rasmus Hedeholm, Malene Simon og John Fleng Steffensen The Greenland shark is ubiquitous in the northern part of the North Atlantic ranging from eastern Canada to northwest Russia . Although knowledge is scarce it is believed to be abundant and potentially...... important part of the ecosystem. Whether Greenland sharks in general should be considered opportunistic scavengers or active predators is therefore important in understanding ecosystem dynamics. Due to its sluggish appearance and a maximum reported swimming speed of 74 cm per second scavenging seems the...... most likely feeding strategy. However, recent studies suggest that Greenland sharks in some areas feed actively upon seals . Feeding ecology is poorly described in Greenland waters. In this study we provide information on feeding habits of 29 sharks caught in Greenland waters in the summer 2012 and...

  7. Predator cannibalism can intensify negative impacts on heterospecific prey.

    Science.gov (United States)

    Takatsu, Kunio; Kishida, Osamu

    2015-07-01

    Although natural populations consist of individuals with different traits, and the degree of phenotypic variation varies among populations, the impact of phenotypic variation on ecological interactions has received little attention, because traditional approaches to community ecology assume homogeneity of individuals within a population. Stage structure, which is a common way of generating size and developmental variation within predator populations, can drive cannibalistic interactions, which can affect the strength of predatory effects on the predator's heterospecific prey. Studies have shown that predator cannibalism weakens predatory effects on heterospecific prey by reducing the size of the predator population and by inducing less feeding activity of noncannibal predators. We predict, however, that predator cannibalism, by promoting rapid growth of the cannibals, can also intensify predation pressure on heterospecific prey, because large predators have large resource requirements and may utilize a wider variety of prey species. To test this hypothesis, we conducted an experiment in which we created carnivorous salamander (Hynobius retardatus) populations with different stage structures by manipulating the salamander's hatch timing (i.e., populations with large or small variation in the timing of hatching), and explored the resultant impacts on the abundance, behavior, morphology, and life history of the salamander's large heterospecific prey, Rana pirica frog tadpoles. Cannibalism was rare in salamander populations having small hatch-timing variation, but was frequent in those having large hatch-timing variation. Thus, giant salamander cannibals occurred only in the latter. We clearly showed that salamander giants exerted strong predation pressure on frog tadpoles, which induced large behavioral and morphological defenses in the tadpoles and caused them to metamorphose late at large size. Hence, predator cannibalism arising from large variation in the timing

  8. Chloral hydrate alters the organization of the ciliary basal apparatus and cell organelles in sea urchin embryos

    Science.gov (United States)

    Chakrabarti, A.; Schatten, H.; Mitchell, K. D.; Crosser, M.; Taylor, M.

    1998-01-01

    The mitotic inhibitor, chloral hydrate, induces ciliary loss in the early embryo phase of Lytechinus pictus. It causes a breakdown of cilia at the junction of the cilium and the basal body known as the basal plate. This leaves the plasma membrane temporarily unsealed. The basal apparatus accessory structures, consisting of the basal body, basal foot, basal foot cap, striated side arm, and striated rootlet, are either misaligned or disintegrated by treatment with chloral hydrate. Furthermore, microtubules which are associated with the basal apparatus are disassembled. Mitochondria accumulate at the base of cilia - underneath the plasma membrane - and show alterations in their structural organization. The accumulation of mitochondria is observed in 40% of all electron micrograph sections while 60% show the areas mostly devoid of mitochondria. The microvilli surrounding a cilium and striated rootlet remain intact in the presence of chloral hydrate. These results suggest that deciliation in early sea urchin embryos by chloral hydrate is caused by combined effects on the ciliary membrane and on microtubules in the cilia. Furthermore, it is suggested that chloral hydrate can serve as a tool to explore the cytoskeletal mechanisms that are involved in cilia motility in the developing sea urchin embryo.

  9. Plant species composition alters the sign and strength of an emergent multi-predator effect by modifying predator foraging behaviour.

    Directory of Open Access Journals (Sweden)

    Andrew Wilby

    Full Text Available The prediction of pest-control functioning by multi-predator communities is hindered by the non-additive nature of species functioning. Such non-additivity, commonly termed an emergent multi-predator effect, is known to be affected by elements of the ecological context, such as the structure and composition of vegetation, in addition to the traits of the predators themselves. Here we report mesocosm experiments designed to test the influence of plant density and species composition (wheat monoculture or wheat and faba bean polyculture on the emergence of multi-predator effects between Adalia bipunctata and Chrysoperla carnea, in their suppression of populations of the aphid Metopolophium dirhodum. The mesocosm experiments were followed by a series of behavioural observations designed to identify how interactions among predators are modified by plant species composition and whether these effects are consistent with the observed influence of plant species composition on aphid population suppression. Although plant density was shown to have no influence on the multi-predator effect on aphid population growth, plant composition had a marked effect. In wheat monoculture, Adalia and Chrysoperla mixed treatments caused greater suppression of M. dirhodum populations than expected. However this positive emergent effect was reversed to a negative multi-predator effect in wheat and faba bean polyculture. The behavioural observations revealed that although dominant individuals did not respond to the presence of faba bean plants, the behaviour of sub-dominants was affected markedly, consistent with their foraging for extra-floral nectar produced by the faba bean. This interaction between plant composition and predator community composition on the foraging behaviour of sub-dominants is thought to underlie the observed effect of plant composition on the multi-predator effect. Thus, the emergence of multi-predator effects is shown to be strongly influenced by

  10. Action of Administered Ciliary Neurotrophic Factor on the Mouse Dorsal Vagal Complex

    Science.gov (United States)

    Senzacqua, Martina; Severi, Ilenia; Perugini, Jessica; Acciarini, Samantha; Cinti, Saverio; Giordano, Antonio

    2016-01-01

    Ciliary neurotrophic factor (CNTF) induces weight loss in obese rodents and humans through activation of the hypothalamic Jak-STAT (Janus kinase-signal transducer and activator of transcription) signaling pathway. Here, we tested the hypothesis that CNTF also affects the brainstem centers involved in feeding and energy balance regulation. To this end, wild-type and leptin-deficient (ob/ob and db/db) obese mice were acutely treated with intraperitoneal recombinant CNTF. Coronal brainstem sections were processed for immunohistochemical detection of STAT3, STAT1, STAT5 phosphorylation and c-Fos. In wild-type mice, CNTF treatment for 45 min induced STAT3, STAT1, and STAT5 phosphorylation in neurons as well as glial cells of the area postrema; here, the majority of CNTF-responsive cells activated multiple STAT isoforms, and a significant proportion of CNTF-responsive glial cells bore the immaturity and plasticity markers nestin and vimentin. After 120 min CNTF treatment, c-Fos expression was intense in glial cells and weak in neurons of the area postrema, it was intense in several neurons of the rostral and caudal solitary tract nucleus (NTS), and weak in some cholinergic neurons of the dorsal motor nucleus of the vagus. In the ob/ob and db/db mice, Jak-STAT activation and c-Fos expression were similar to those induced in wild-type mouse brainstem. Treatment with CNTF (120 min, to induce c-Fos expression) and leptin (25 min, to induce STAT3 phosphorylation) demonstrated the co-localization of the two transcription factors in a small neuron population in the caudal NTS portion. Finally, weak immunohistochemical CNTF staining, detected in funiculus separans, and meningeal glial cells, matched the modest amount of CNTF found by RT-qPCR in micropunched area postrema tissue, which in contrast exhibited a very high amount of CNTF receptor. Collectively, the present findings show that the area postrema and the NTS exhibit high, distinctive responsiveness to circulating

  11. Action of Administered Ciliary Neurotrophic Factor on the Mouse Dorsal Vagal Complex.

    Science.gov (United States)

    Senzacqua, Martina; Severi, Ilenia; Perugini, Jessica; Acciarini, Samantha; Cinti, Saverio; Giordano, Antonio

    2016-01-01

    Ciliary neurotrophic factor (CNTF) induces weight loss in obese rodents and humans through activation of the hypothalamic Jak-STAT (Janus kinase-signal transducer and activator of transcription) signaling pathway. Here, we tested the hypothesis that CNTF also affects the brainstem centers involved in feeding and energy balance regulation. To this end, wild-type and leptin-deficient (ob/ob and db/db) obese mice were acutely treated with intraperitoneal recombinant CNTF. Coronal brainstem sections were processed for immunohistochemical detection of STAT3, STAT1, STAT5 phosphorylation and c-Fos. In wild-type mice, CNTF treatment for 45 min induced STAT3, STAT1, and STAT5 phosphorylation in neurons as well as glial cells of the area postrema; here, the majority of CNTF-responsive cells activated multiple STAT isoforms, and a significant proportion of CNTF-responsive glial cells bore the immaturity and plasticity markers nestin and vimentin. After 120 min CNTF treatment, c-Fos expression was intense in glial cells and weak in neurons of the area postrema, it was intense in several neurons of the rostral and caudal solitary tract nucleus (NTS), and weak in some cholinergic neurons of the dorsal motor nucleus of the vagus. In the ob/ob and db/db mice, Jak-STAT activation and c-Fos expression were similar to those induced in wild-type mouse brainstem. Treatment with CNTF (120 min, to induce c-Fos expression) and leptin (25 min, to induce STAT3 phosphorylation) demonstrated the co-localization of the two transcription factors in a small neuron population in the caudal NTS portion. Finally, weak immunohistochemical CNTF staining, detected in funiculus separans, and meningeal glial cells, matched the modest amount of CNTF found by RT-qPCR in micropunched area postrema tissue, which in contrast exhibited a very high amount of CNTF receptor. Collectively, the present findings show that the area postrema and the NTS exhibit high, distinctive responsiveness to circulating

  12. Evasion of predators contributes to the maintenance of male eyes in sexually dimorphic Euphilomedes ostracods (Crustacea).

    Science.gov (United States)

    Speiser, Daniel I; Lampe, Rebecca I; Lovdahl, Valerie R; Carrillo-Zazueta, Brenna; Rivera, Ajna S; Oakley, Todd H

    2013-07-01

    Sexual dimorphisms have long drawn the attention of evolutionary biologists. However, we still have much to learn about the evolutionary, genetic, and developmental drivers of sexual dimorphisms. Here, we introduce ostracods of the genus Euphilomedes (Myodocopida, Ostracoda, and Crustacea) as a promising new system in which to investigate why and how sexual dimorphisms evolve. First, we ask whether male-skewed selective pressure from pelagic predators may help explain a dramatic sexual dimorphism in which male Euphilomedes have compound eyes, but females do not. Manipulative experiments demonstrate that blindfolding reduces the survival rate of male Euphilomedes when they are exposed to predatory fish. Blindfolding of the female rudimentary eyes (rudiments) does not, however, similarly influence the survival rate of brooding females. Further, numerical estimates of sighting distances, based on reasonable extrapolations from Euphilomedes's eye morphology, suggest that the eyes of male Euphilomedes are useful for detecting objects roughly the size of certain pelagic predators, but not conspecifics. We conclude that eyes do not mediate direct interactions between male and female Euphilomedes, but that differences in predation pressure-perhaps associated with different reproductive behaviors-contribute to maintaining the sexually dimorphic eyes of these ostracods. Second, through transcriptome sequencing, we examined potential gene regulatory networks that could underlie sexual dimorphism in Euphilomedes' eyes. From the transcriptome of juvenile male Euphilomedes' eyes, we identified phototransduction genes and components of eye-related developmental networks that are well characterized in Drosophila and other species. The presence of suites of eye regulatory genes in our Euphilomedes juvenile male transcriptome will allow us, in future studies, to test how ostracods regulate the development of their sexually dimorphic eyes. PMID:23652199

  13. Developmental thermal plasticity of prey modifies the impact of predation.

    Science.gov (United States)

    Seebacher, Frank; Grigaltchik, Veronica S

    2015-05-01

    Environmental conditions during embryonic development can influence the mean expression of phenotypes as well as phenotypic responses to environmental change later in life. The resulting phenotypes may be better matched to their environment and more resilient to environmental change, including human-induced climate change. However, whether plasticity does improve success in an ecological context is unresolved. In a microcosm experiment, we show that developmental plasticity in embryos of the frog Limnodynastes peronii is beneficial by increasing survivorship of tadpoles in the presence of predators when egg incubation (15 or 25°C) and tadpole acclimation temperature in microcosms (15 or 25°C) coincided at 15°C. Tadpoles that survived predation were smaller, and had faster burst swimming speeds than those kept in no-predator control conditions, but only at high (25°C) egg incubation or subsequent microcosm temperatures. Metabolic rates were determined by a three-way interaction between incubation and microcosm temperatures and predation; maximal glycolytic and mitochondrial metabolic capacities (enzyme activities) were lower in survivors from predation compared with controls, particularly when eggs were incubated at 25°C. We show that thermal conditions experienced during early development are ecologically relevant by modulating survivorship from predation. Importantly, developmental thermal plasticity also impacts population phenotypes indirectly by modifying species interactions and the selection pressure imposed by predation. PMID:25767143

  14. Aquatic macroinvertebrate responses to native and non-native predators

    Directory of Open Access Journals (Sweden)

    Haddaway N. R.

    2014-01-01

    Full Text Available Non-native species can profoundly affect native ecosystems through trophic interactions with native species. Native prey may respond differently to non-native versus native predators since they lack prior experience. Here we investigate antipredator responses of two common freshwater macroinvertebrates, Gammarus pulex and Potamopyrgus jenkinsi, to olfactory cues from three predators; sympatric native fish (Gasterosteus aculeatus, sympatric native crayfish (Austropotamobius pallipes, and novel invasive crayfish (Pacifastacus leniusculus. G. pulex responded differently to fish and crayfish; showing enhanced locomotion in response to fish, but a preference for the dark over the light in response to the crayfish. P.jenkinsi showed increased vertical migration in response to all three predator cues relative to controls. These different responses to fish and crayfish are hypothesised to reflect the predators’ differing predation types; benthic for crayfish and pelagic for fish. However, we found no difference in response to native versus invasive crayfish, indicating that prey naiveté is unlikely to drive the impacts of invasive crayfish. The Predator Recognition Continuum Hypothesis proposes that benefits of generalisable predator recognition outweigh costs when predators are diverse. Generalised responses of prey as observed here will be adaptive in the presence of an invader, and may reduce novel predators’ potential impacts.

  15. Mapping risk for nest predation on a barrier island

    Science.gov (United States)

    Hackney, Amanda D.; Baldwin, Robert F.; Jodice, Patrick G.

    2013-01-01

    Barrier islands and coastal beach systems provide nesting habitat for marine and estuarine turtles. Densely settled coastal areas may subsidize nest predators. Our purpose was to inform conservation by providing a greater understanding of habitat-based risk factors for nest predation, for an estuarine turtle. We expected that habitat conditions at predated nests would differ from random locations at two spatial extents. We developed and validated an island-wide model for the distribution of predated Diamondback terrapin nests using locations of 198 predated nests collected during exhaustive searches at Fisherman Island National Wildlife Refuge, USA. We used aerial photographs to identify all areas of possible nesting habitat and searched each and surrounding environments for nests, collecting location and random-point microhabitat data. We built models for the probability of finding a predated nest using an equal number of random points and validated them with a reserve set (N = 67). Five variables in 9 a priori models were used and the best selected model (AIC weight 0.98) reflected positive associations with sand patches near marshes and roadways. Model validation had an average capture rate of predated nests of 84.14 % (26.17–97.38 %, Q1 77.53 %, median 88.07 %, Q3 95.08 %). Microhabitat selection results suggest that nests placed at the edges of sand patches adjacent to upland shrub/forest and marsh systems are vulnerable to predation. Forests and marshes provide cover and alternative resources for predators and roadways provide access; a suggestion is to focus nest protection efforts on the edges of dunes, near dense vegetation and roads.

  16. Does a Simple Cope's Rule Mechanism Overlook Predators?

    International Nuclear Information System (INIS)

    The Copes rule predicts a tendency for species to evolve towards an increase in size. Recently, it has been suggested that such a tendency is due to the fact that large body sizes provide a general increase in individual fitness. Here we highlight evidence that predator species do not always fit the large-size = high-fitness mechanism for Copes rule. Given the specific requirements of predators and the complexity of prey-predator relationships, any analysis that does not take into account all animal groups may overlook a significant portion of evolutive trends. Generalisations may not be possible regardless of taxa.

  17. Does a Simple Cope's Rule Mechanism Overlook Predators?

    Directory of Open Access Journals (Sweden)

    Vincenzo Penteriani

    2007-01-01

    Full Text Available The Cope’s rule predicts a tendency for species to evolve towards an increase in size. Recently, it has been suggested that such a tendency is due to the fact that large body sizes provide a general increase in individual fitness. Here we highlight evidence that predator species do not always fit the large-size = high-fitness mechanism for Cope’s rule. Given the specific requirements of predators and the complexity of prey-predator relationships, any analysis that does not take into account all animal groups may overlook a significant portion of evolutive trends. Generalisations may not be possible regardless of taxa.

  18. A conserved role for Notch in priming the cellular response to Shh through ciliary localisation of the key Shh transducer, Smoothened

    DEFF Research Database (Denmark)

    Stasiulewicz, Magdalena; Gray, Shona; Mastromina, Ioanna;

    2015-01-01

    , we show Notch activity promotes longer primary cilia both in vitro and in vivo. Strikingly, these Notch-regulated effects are Shh-independent. These data identify Notch signalling as a novel modulator of Shh signalling which acts mechanistically via regulation of ciliary localisation of key...

  19. Ciliary neurotrophic factor activates NF-κB to enhance mitochondrial bioenergetics and prevent neuropathy in sensory neurons of streptozotocin-induced diabetic rodents

    OpenAIRE

    Saleh, Ali; Roy Chowdhury, Subir K.; Smith, Darrel R.; Balakrishnan, Savitha; Tessler, Lori; Martens, Corina; Morrow, Dwane; Schartner, Emily; Frizzi, Katie E.; Calcutt, Nigel A.; Fernyhough, Paul

    2012-01-01

    Diabetes causes mitochondrial dysfunction in sensory neurons that may contribute to peripheral neuropathy. Ciliary neurotrophic factor (CNTF) promotes sensory neuron survival and axon regeneration and prevents axonal dwindling, nerve conduction deficits and thermal hypoalgesia in diabetic rats. In this study, we tested the hypothesis that CNTF protects sensory neuron function during diabetes through normalization of impaired mitochondrial bioenergetics. In addition, we investigated whether th...

  20. Intravitreal injection of ciliary neurotrophic factor (CNTF) causes peripheral remodeling and does not prevent photoreceptor loss in canine RPGR mutant retina

    OpenAIRE

    Beltran, William A.; Wen, Rong; Acland, Gregory M.; Aguirre, Gustavo D.

    2007-01-01

    Ciliary neurotrophic factor (CNTF) rescues photoreceptors in several animal models of retinal degeneration and is currently being evaluated as a potential treatment for retinitis pigmentosa in humans. This study was conducted to test whether CNTF prevents photoreceptor cell loss in XLPRA2, an early onset canine model of X-linked retinitis pigmentosa caused by a frameshift mutation in RPGR exon ORF15.

  1. Predator swamping reduces predation risk during nocturnal migration of juvenile salmon in a high-mortality landscape.

    Science.gov (United States)

    Furey, Nathan B; Hinch, Scott G; Bass, Arthur L; Middleton, Collin T; Minke-Martin, Vanessa; Lotto, Andrew G

    2016-07-01

    Animal migrations are costly and are often characterized by high predation risk for individuals. Three of the most oft-assumed mechanisms for reducing risk for migrants are swamping predators with high densities, specific timing of migrations and increased body size. Assessing the relative importance of these mechanisms in reducing predation risk particularly for migrants is generally lacking due to the difficulties in tracking the fate of individuals and population-level characteristics simultaneously. We used acoustic telemetry to track migration behaviour and survival of juvenile sockeye salmon (Oncorhynchus nerka) smolts released over a wide range of conspecific outmigration densities in a river associated with poor survival. The landscape was indeed high risk; smolt survival was poor (˜68%) over 13·5 km of river examined even though migration was rapid (generally <48 h). Our results demonstrate that smolts largely employ swamping of predators to reduce predation risk. Increased densities of co-migrant conspecifics dramatically improved survival of smolts. The strong propensity for nocturnal migration resulted in smolts pausing downstream movements until the next nightfall, greatly increasing relative migration durations for smolts that could not traverse the study area in a single night. Smolt size did not appear to impact predation risk, potentially due to unique characteristics of the system or our inability to tag the entire size range of outmigrants. Movement behaviours were important in traversing this high-risk landscape and provide rare evidence for swamping to effectively reduce individual predation risk. PMID:27159553

  2. Distance-responsive predation is not necessary for the Janzen-Connell hypothesis.

    Science.gov (United States)

    Stump, Simon Maccracken; Chesson, Peter

    2015-12-01

    The Janzen-Connell hypothesis states that tree diversity in tropical forests is maintained by specialist predators that are distance- or density-responsive (i.e. predators that reduce seed or seedling survival near adults of their hosts). Many empirical studies have investigated whether predators are distance-responsive; however, few studies have examined whether distance-responsiveness matters for how predators maintain tree diversity. Using a site-occupancy model, we show analytically that distance-responsive predators are actually less able to maintain diversity than specialist predators that are not distance-responsive. Generally, specialist predators maintain diversity because they become rare when their host's densities are low, reducing predation risk. However, if predators are distance-responsive, and most seeds cannot disperse away from these predators, then seed predation rates will remain high, even if predator density is low across the landscape. Consequently, a reduction in a host's population density may not lead to a significant reduction in seed and seedling predation. We show that habitat partitioning can cause recruitment to be highest near conspecific adults, even in the presence of distance-responsive predators, without any change in the effect that the predators have on coexistence (a result contrary to predictions of the Janzen-Connell hypothesis). Rather, specialist predators and habitat partitioning have additive effects on species coexistence in our model, i.e., neither mechanism alters the effect of the other one. PMID:26525355

  3. How do brent geese (Branta b. bernicla) cope with evil?; complex relationships between predators and prey

    NARCIS (Netherlands)

    Ebbinge, B.S.; Spaans, B.

    2002-01-01

    Actual predation is rarely observed in the field, and therefore the role of predators is often severely underestimated. Species are limited in their distribution, which is caused not only by predation but also by the anti-predator behaviour that prey-species have developed under the continuous selec

  4. Response of coyotes to avian distress calls : testing the startle-predator and predator-attraction hypotheses

    OpenAIRE

    Knowlton, Frederick; Conover, Michael R.; Wise, Kristi K.

    1999-01-01

    We tested two hypotheses proposed to explain why many birds emit distress calls when in the grasp of a predator: the startle-predator and predator-attraction hypotheses. Responses of captive coyotes to a starling distress call were compared between no-call and call trials to determine whether coyotes are startled by the call, and if so, whether they habituated to it. The coyotes were then paired and re-tested to determine whether the call incites a second coyote to approach and interfere with...

  5. Predation of the Peach Aphid Myzus persicae by the mirid Predator Macrolophus pygmaeus on Sweet Peppers: Effect of Prey and Predator Density

    Directory of Open Access Journals (Sweden)

    Lara De Backer

    2015-06-01

    Full Text Available Integrated Pest Management strategies are widely implemented in sweet peppers. Aphid biological control on sweet pepers includes curative applications of parasitoids and generalist predators, but with limited efficiency. Macrolophus pygmaeus is a zoophytophagous predator which has been reported to predate on aphids, but has traditionally been used to control other pests, including whiteflies. In this work, we evaluate the effectiveness of M. pygmaeus in controlling Myzus persicae (Homoptera: Aphididae by testing different combinations of aphid and predator densities in cage-experiments under greenhouse conditions. The impact of the presence of an alternative factitious prey (E. kuehniella eggs was also investigated. Macrolophus pygmaeus, at densities of four individuals/plant, caused rapid decline of newly established aphid populations. When aphid infestations were heavy, the mirid bug reduced the aphid numbers but did not fully eradicate aphid populations. The availability of a factitious prey did not influence M. pygmaeus predation on aphids. Based on our data, preventive application of M. pygmaeus, along with a supplementary food source , is recommended to control early infestations of aphids.

  6. Accuracy and repeatability of direct ciliary sulcus diameter measurements by full-scale 50-megahertz ultrasound biomicroscopy

    Institute of Scientific and Technical Information of China (English)

    LI De-jiao; WANG Ning-li; CHEN Shu; LI Shu-ning; MU Da-peng; WANG Tao

    2009-01-01

    Background Phakic intraocular lens (pIOL) implantation has been a popular means for the treatment of high ametropia. Measurements of ciliary sulcus diameter is important for pIOL size determining. But till now, no perfect system can directly measure it. The present study was to evaluate the accuracy, repeatability and reproducibility of direct sulcus diameter measurements obtained by a full-scale 50-megahertz (MHz) ultrasound biomicroscopy (UBM).Methods A fresh cadaver human eye with a scale marker inserted through the posterior chamber plane from 3 o'clock to 9 o'clock meridian and 30 randomly selected eyes from 30 normal subjects were scanned by full-scale 50-MHz UBM in horizontal meridional scan plane. The distance between the scales and the whole length of the marker inside the cadaver eye were measured by the same observer using the "built-in" measurement tools and the indicating error of instrument was calculated. Reproducibility of the measurement was evaluated in 30 eyes by 2 operators using Blander and Altman plot test. Repeatability was evaluated from 10 successive eyes randomly selected from the 30 eyes by one operator.Results On a scale of 1 mm, the greatest indicating error was 40 μm; the mean largest indicating error of 1 mm scale from the 10 images was (26±14) μm; on a scale of 11 mm, the greatest indicating error was 70 μo; the error rate was 0.64%. The mean length of the needle inside the eye of the 10 images was 11.05 mm, with the mean indicating error of 47 μm, the average error rate was 0.43%. For ciliary sulcus diameter measurements in vivo, the coefficient of variation was 0.38%; the coefficients of repeatability for intra-observer and inter-observer measurements were 1.99% and 2.55%, respectively. The limits of agreement for intra-observer and inter-observer measurement were-0.41 mm to 0.48 mm and -0.59 mm to 0.58 ram, respectively.Conclusion The full-scale 50-MHz UBM can be a high accuracy and good repeatability means for direct

  7. Forage supply in thinned Caatinga enriched with buffel grass (Cenchrus ciliaris L. grazed by goats and sheep=Oferta de forragem em Caatinga raleada e enriquecida com capim buffel (Cenchrus ciliaris L. pastejada por ovinos e caprinos

    Directory of Open Access Journals (Sweden)

    Diogo da Costa Soares

    2012-04-01

    Full Text Available Forage supply from herbs was assessed in a thinned Caatinga enriched with buffel grass (Cenchrus ciliaris L. exposed to goat and sheep grazing. The 2.4 ha experimental area, located at the Experimental Station of the Federal University of Campina Grande, in Santa Terezinha, Paraíba State, Brazil, was divided into four 0.6 ha paddocks, which were further subdivided into two 0.3 ha experimental plots. Twelve F1 (Boer x SRD goats and 12 Santa Inês sheep were divided in four groups of six animals of the same species. The herbaceous vegetation was separated into buffel grass (Cenchrus ciliaris L., dicotyledons and other grass species. Treatments were randomized to plots according to a completely random design with two treatments, four replications, with measures repeated in time (July/1, Aug/1, Sept/1 and Oct/1. Buffel grass dry mater (DM availability was higher in the sheep grazed than in the goat-grazed area. Buffel grass DM supply did not change from July to September, while dicotyledons DM supply decreased. Grazing affected availability, accumulation rate and supply of the forage produced (DM basis by dicotyledonous herbs. Buffel grass forage availability was not affected during the experimental period.Objetivou-se avaliar a oferta de forragem do estrato herbáceo de uma Caatinga raleada e enriquecida com capim buffel (Cenchrus ciliaris L., submetida ao pastejo de caprinos e ovinos. O experimento foi realizado na Universidade Federal de Campina Grande, Estado da Paraíba. A área experimental foi de 2,4 ha, dividida em quatro piquetes de 0,6 ha, nos quais foram alocadas parcelas experimentais de 0,3 ha. Utilizaram-se 12 caprinos F1 (Bôer x SRD e 12 ovinos Santa Inês, que foram distribuídos em quatro grupos de seis animais. A vegetação herbácea foi separada em capim buffel (Cenchrus ciliaris L., dicotiledôneas e outras gramínea. Utilizou-se um delineamento inteiramente casualizado, com observações repetidas no tempo (1/jul., 1/ago., 1

  8. NONLINEAR SINGULARLY PERTURBED PREDATOR-PREY REACTION DIFFUSION SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    MoJiaqi; TangRongrong

    2004-01-01

    A class of nonlinear predator-prey reaction diffusion systems for singularly perturbedproblems are considered. Under suitable conditions, by using theory of differential inequalitiesthe existence and asymptotic behavior of solution for initial boundary value problems arestudied.

  9. Cormorant predation on PIT-tagged lake fish

    DEFF Research Database (Denmark)

    Skov, Christian; Jepsen, Niels; Baktoft, Henrik;

    2014-01-01

    The present study use data from recovered PIT (Passive Integrated Transponder) tags to explore species-and size-specific annual predation rates by cormorants on three common lacustrine fishes (size range 120-367 mm) in a European lake; roach (Rutilus rutilus), common bream (Abramis brama) and perch...... (Perca fluviatilis). In addition, we quantify the level of age/size truncation that cormorant predation could introduce in a population of perch, an important fish for recreational angling as well as for trophic interactions and ecosystem function in European lakes. Based on three years of PIT tagging of...... fish in Lake Viborg and subsequent recoveries of PIT tags from nearby cormorant roosting and breeding sites, we show that cormorants are major predators of roach, bream and perch within the size groups we investigated and for all species larger individuals had higher predation rates. Perch appear to be...

  10. [Predator disease sampling results in Montana 1993-1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains data from predator disease sampling in Montana for the reintroduction of black-footed ferrets at Charles M. Russell National Wildlife Refuge....

  11. Apparent predation by cattle at grassland bird nests

    Science.gov (United States)

    Nack, J.L.; Ribic, C.A.

    2005-01-01

    We document the first cases of cattle behaving as avian predators, removing nestlings and eggs from three active ground nests in continuously grazed pastures in southwestern Wisconsin, 2000-2001. Cows removed three of four Savannah Sparrow (Passerculus sandwichensis) eggs from one nest (the fourth egg was damaged), all four Eastern Meadowlark (Sturnella magna) nestlings from another, and all three Savannah Sparrow nestlings from a third. We found only two of three missing eggs (intact) and one of seven missing nestlings (dead) near two of the nests. Cows may have eaten the egg and nestlings we were unable to account for; alternatively, the egg and nestlings may have been scavenged by predators or removed from the area by the adult birds. Without videotape documentation, we would have attributed nest failure to traditional predators and cattle would not have been implicated. We may be underestimating the impact of cattle on ground nests by not considering cattle as potential predators.

  12. Global Tagging of Pelagic Predators (GTOPP) Animal Tracking Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data (updated daily) are from the Global Tagging of Pelagic Predators (GTOPP) program. Begun as one of the field projects in the international Census of...

  13. [Approval of predator management activities in North Dakota, 2005

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Request from U.S. Fish and Wildlife Service and approval from North Dakota Game & Fish Department for predator management activities outside of the state...

  14. Predation by Neotropical Otters (Lontra longicaudis on Turtles in Belize

    Directory of Open Access Journals (Sweden)

    Thomas R. Rainwater

    2011-01-01

    Full Text Available We report observations of turtle (Dermatemys mawii and Trachemys venusta predation by Lontra longicaudis at Cox Lagoon, Belize. On 10 June 1994, we observed an otter swimming with a juvenile D. mawii in its jaws. During a subsequent search (25 June and 5 July 1994 we found 35 D. mawii shells or partially eaten carcasses, and a single, partially eaten adult T. venusta that had apparently been killed by otters. Based on the size of these turtles, juvenile and subadult D. mawii seem most vulnerable to otter predation. Because otter predation of D. mawii appears rare in Belize, and most reproductively mature D. mawii are probably too large to be caught and killed by foraging otters, we do not consider predation by L. longicaudis to be a serious threat to populations of this critically endangered turtle.

  15. Perceptual advertisement by the prey of stalking or ambushing predators

    OpenAIRE

    Broom, M.; Ruxton, G.D

    2012-01-01

    There has been previous theoretical explorations of the stability of signals by prey that they have detected a stalking or ambush predator, where such perceptual advertisement dissuades the predator from attacking. Here we use a game theoretical model to extend the theory to consider some empirically-motivated complexities: (i) many perceptual advertisement signals appear to have the potential to vary in intensity, (ii) higher intensity signals are likely to be most costly to produce, and (ii...

  16. Brain development and predation: plastic responses depend on evolutionary history

    OpenAIRE

    Gonda, Abigél; Välimäki, Kaisa; Herczeg, Gábor; Merilä, Juha

    2011-01-01

    Although the brain is known to be a very plastic organ, the effects of common ecological interactions like predation or competition on brain development have remained largely unexplored. We reared nine-spined sticklebacks (Pungitius pungitius) from two coastal marine (predation-adapted) and two isolated pond (competition-adapted) populations in a factorial experiment, manipulating perceived predatory risk and food supply to see (i) if the treatments affected brain development and (ii) if ther...

  17. Predation by ants on arthropods and other animals

    OpenAIRE

    Cerdá, Xim; Dejean, A

    2011-01-01

    Ants are the most widely distributed and most numerically abundant group of social insects. First, they were ground- or litter-dwelling predators or scavengers, and certain taxa evolved to adopt an arboreal way of life. Most ant species are generalist feeders, and only some ground-nesting and ground- foraging species are strictly predators. Ants are central-place foragers (with the exception of army ants during the nomadic phase) that may use different foraging strategies. Solitary hunting is...

  18. Prey-predator model with a nonlocal consumption of prey.

    Science.gov (United States)

    Banerjee, M; Volpert, V

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology. PMID:27586616

  19. Balancing food and predator pressure induces chronic stress in songbirds.

    OpenAIRE

    Clinchy, Michael; Zanette, Liana; Boonstra, Rudy; Wingfield, John C.; Smith, James N. M.

    2004-01-01

    The never-ending tension between finding food and avoiding predators may be the most universal natural stressor wild animals experience. The 'chronic stress' hypothesis predicts: (i) an animal's stress profile will be a simultaneous function of food and predator pressures given the aforesaid tension; and (ii) these inseparable effects on physiology will produce inseparable effects on demography because of the resulting adverse health effects. This hypothesis was originally proposed to explain...

  20. Early Triassic Marine Biotic Recovery: The Predators' Perspective

    OpenAIRE

    Scheyer, Torsten M.; Carlo Romano; Jim Jenks; Hugo Bucher

    2014-01-01

    Examining the geological past of our planet allows us to study periods of severe climatic and biological crises and recoveries, biotic and abiotic ecosystem fluctuations, and faunal and floral turnovers through time. Furthermore, the recovery dynamics of large predators provide a key for evaluation of the pattern and tempo of ecosystem recovery because predators are interpreted to react most sensitively to environmental turbulences. The end-Permian mass extinction was the most severe crisis e...

  1. Titi monkey call sequences vary with predator location and type.

    OpenAIRE

    Casar, C.; Zuberbuhler, K.; Young, R. J.; Byrne, R.W.

    2013-01-01

    Animal alarm calls can encode information about a predator's category, size, distance or threat level. In non-human primates, alarm calls typically refer to broad classes of disturbances, in some instances to specific predators. Here, we present the results of a field experiment with a New World primate, the black-fronted titi monkey (Callicebus nigrifrons), designed to explore the information conveyed by their alarm call system. Adults produced sequences consisting of two main alarm call typ...

  2. Predator-induced morphology enhances escape locomotion in crucian carp

    OpenAIRE

    Domenici, Paolo; Turesson, Håkan; Brodersen, Jakob; Brönmark, Christer

    2007-01-01

    Fishes show a remarkable diversity of shapes which have been associated with their swimming abilities and anti-predator adaptations. The crucian carp (Carassius carassius) provides an extreme example of phenotypic plasticity in body shape which makes it a unique model organism for evaluating the relationship between body form and function in fishes. In crucian carp, a deep body is induced by the presence of pike (Esox lucius), and this results in lower vulnerability to gape-limited predators,...

  3. Persistent predator-prey dynamics revealed by mass extinction.

    Science.gov (United States)

    Sallan, Lauren Cole; Kammer, Thomas W; Ausich, William I; Cook, Lewis A

    2011-05-17

    Predator-prey interactions are thought by many researchers to define both modern ecosystems and past macroevolutionary events. In modern ecosystems, experimental removal or addition of taxa is often used to determine trophic relationships and predator identity. Both characteristics are notoriously difficult to infer in the fossil record, where evidence of predation is usually limited to damage from failed attacks, individual stomach contents, one-sided escalation, or modern analogs. As a result, the role of predation in macroevolution is often dismissed in favor of competition and abiotic factors. Here we show that the end-Devonian Hangenberg event (359 Mya) was a natural experiment in which vertebrate predators were both removed and added to an otherwise stable prey fauna, revealing specific and persistent trophic interactions. Despite apparently favorable environmental conditions, crinoids diversified only after removal of their vertebrate consumers, exhibiting predatory release on a geological time scale. In contrast, later Mississippian (359-318 Mya) camerate crinoids declined precipitously in the face of increasing predation pressure from new durophagous fishes. Camerate failure is linked to the retention of obsolete defenses or "legacy adaptations" that prevented coevolutionary escalation. Our results suggest that major crinoid evolutionary phenomena, including rapid diversification, faunal turnover, and species selection, might be linked to vertebrate predation. Thus, interactions observed in small ecosystems, such as Lotka-Volterra cycles and trophic cascades, could operate at geologic time scales and higher taxonomic ranks. Both trophic knock-on effects and retention of obsolete traits might be common in the aftermath of predator extinction. PMID:21536875

  4. Nash Equilibria in Noncooperative Predator-Prey Games

    International Nuclear Information System (INIS)

    A noncooperative game governed by a distributed-parameter predator-prey system is considered, assuming that two players control initial conditions for predator and prey, respectively. Existence of a Nash equilibrium is shown under the condition that the desired population profiles and the environmental carrying capacity for the prey are sufficiently small. A conceptual approximation algorithm is proposed and analyzed. Finally, numerical simulations are performed, too

  5. Factors affecting egg predation in Black-tailed Gulls

    OpenAIRE

    Kazama, Kentaro

    2007-01-01

    In colonial seabirds, nesting density, egg-laying date and nest microhabitat affect the probability of eggs being taken by avian predators. Jungle Crows (Corvus macrorhynchos) are dominant predators of eggs of Black-tailed Gulls (Larus crassirostris). Factors affecting the probability of gulls allowing the crows to attack their nests or depredate their eggs and the probability of eggs being taken were studied by direct observation and egg census, respectively. The effect of vegetation heights...

  6. California current system - Predators and the preyscape

    Science.gov (United States)

    Ainley, David G.; Adams, Peter B.; Jahncke, Jaime

    2015-06-01

    The preyscape of the California Current System (CCS), one of the most productive marine areas on Earth (Glantz and Thompson, 1981), is highly variable, as evidenced by the papers in this issue, and as such presents a challenge to Ecosystem-based fishery management (EBFM), which attempts to integrate ecosystem considerations as part of fishery management and conservation decisions. Approaches to EBFM for the waters off Washington, Oregon, and California, the CCS, have been initiated (PFMC, 2007, 2013), and are continually being developed. To inform this process, a workshop was held in September 2013 to: i) gather together the existing information on forage fish and predator dynamics in the CCS; ii) consider temporal (seasonal, annual, decadal) and spatial availability of prey complexes and why these patterns of availability occur and change; iii) summarize and present that information for discussion to a large range of experts in oceanography, fish and fisheries management, seabirds, marine mammals, and ecosystem management; and, iv) synthesize this information to be useable by fishery agencies. The papers in this special Journal of Marine Systems issue address these four points. While the full results and recommendations can be found here - "http://www.pointblue.org/uploads/assets/calcurrent/REPORT_Forage_Fish_Workshop_FINAL.pdf"

  7. Cormorant predation on PIT-tagged lake fish

    Directory of Open Access Journals (Sweden)

    Christian Skov

    2014-02-01

    Full Text Available The present study use data from recovered PIT (Passive Integrated Transponder tags to explore species- and size-specific annual predation rates by cormorants on three common lacustrine fishes (size range 120-367 mm in a European lake; roach (Rutilus rutilus, common bream (Abramis brama and perch (Perca fluviatilis. In addition, we quantify the level of age/size truncation that cormorant predation could introduce in a population of perch, an important fish for recreational angling as well as for trophic interactions and ecosystem function in European lakes. Based on three years of PIT tagging of fish in lake Viborg and subsequent recoveries of PIT tags from nearby cormorant roosting and breeding sites, we show that cormorants are major predators of roach, bream and perch within the size groups we investigated and for all species larger individuals had higher predation rates. Perch appear to be the most vulnerable of the three species and based on a comparison with mortality estimates from lakes without significant avian predation, this study suggest that predation from cormorants can induce age/size truncation in lake Viborg, leaving very few larger perch in the lake. This truncation reduces the likelihood of anglers catching a large perch and may also influence lower trophic levels in the lake and thus turbidity as large piscivorous perch often play an important structuring role in lake ecosystem functioning.

  8. Fighting parasites and predators: How to deal with multiple threats?

    Directory of Open Access Journals (Sweden)

    Hesse Olivia

    2012-07-01

    Full Text Available Abstract Background Although inducible defences have been studied extensively, only little is known about how the presence of parasites might interfere with these anti-predator adaptations. Both parasites and predators are important factors shaping community structure and species composition of ecosystems. Here, we simultaneously exposed Daphnia magna to predator cues (released by the tadpole shrimp, Triops, or by a fish and spores of the yeast parasite Metschnikowia sp. to determine how life history and morphological inducible defences against these two contrasting types of predators are affected by infection. Results The parasite suppressed some Triops-induced defences: Daphnia lost the ability to produce a greater number of larger offspring, a life-history adaptation to Triops predation. In contrast, the parasite did not suppress inducible defences against fish: induction (resulting in smaller body length of the mothers as well as of their offspring and infection acted additively on the measured traits. Thus, fish-induced defences may be less costly than inducible defences against small invertebrate predators like Triops; the latter defences could no longer be expressed when the host had already invested in fighting off the parasite. Conclusions In summary, our study suggests that as specific inducible defences differ in their costs, some might be suppressed if a target prey is additionally infected. Therefore, adding parasite pressure to predator–prey systems can help to elucidate the costs of inducible defences.

  9. Human shields mediate sexual conflict in a top predator.

    Science.gov (United States)

    Steyaert, S M J G; Leclerc, M; Pelletier, F; Kindberg, J; Brunberg, S; Swenson, J E; Zedrosser, A

    2016-06-29

    Selecting the right habitat in a risky landscape is crucial for an individual's survival and reproduction. In predator-prey systems, prey often can anticipate the habitat use of their main predator and may use protective associates (i.e. typically an apex predator) as shields against predation. Although never tested, such mechanisms should also evolve in systems in which sexual conflict affects offspring survival. Here, we assessed the relationship between offspring survival and habitat selection, as well as the use of protective associates, in a system in which sexually selected infanticide (SSI), rather than interspecific predation, affects offspring survival. We used the Scandinavian brown bear (Ursus arctos) population with SSI in a human-dominated landscape as our model system. Bears, especially adult males, generally avoid humans in our study system. We used resource selection functions to contrast habitat selection of GPS-collared mothers that were successful (i.e. surviving litters, n = 19) and unsuccessful (i.e. complete litter loss, n = 11) in keeping their young during the mating season (2005-2012). Habitat selection was indeed a predictor of litter survival. Successful mothers were more likely to use humans as protective associates, whereas unsuccessful mothers avoided humans. Our results suggest that principles of predator-prey and fear ecology theory (e.g. non-consumptive and cascading effects) can also be applied to the context of sexual conflict. PMID:27335423

  10. Predation risk drives social complexity in cooperative breeders.

    Science.gov (United States)

    Groenewoud, Frank; Frommen, Joachim Gerhard; Josi, Dario; Tanaka, Hirokazu; Jungwirth, Arne; Taborsky, Michael

    2016-04-12

    Predation risk is a major ecological factor selecting for group living. It is largely ignored, however, as an evolutionary driver of social complexity and cooperative breeding, which is attributed mainly to a combination of habitat saturation and enhanced relatedness levels. Social cichlids neither suffer from habitat saturation, nor are their groups composed primarily of relatives. This demands alternative ecological explanations for the evolution of advanced social organization. To address this question, we compared the ecology of eight populations of Neolamprologus pulcher, a cichlid fish arguably representing the pinnacle of social evolution in poikilothermic vertebrates. Results show that variation in social organization and behavior of these fish is primarily explained by predation risk and related ecological factors. Remarkably, ecology affects group structure more strongly than group size, with predation inversely affecting small and large group members. High predation and shelter limitation leads to groups containing few small but many large members, which is an effect enhanced at low population densities. Apparently, enhanced safety from predators by cooperative defense and shelter construction are the primary benefits of sociality. This finding suggests that predation risk can be fundamental for the transition toward complex social organization, which is generally undervalued. PMID:27035973

  11. FUNCTIONAL RESPONSE- A FUNCTION OF PREDATOR AND PREY SPECIES

    Directory of Open Access Journals (Sweden)

    MOHD ABAS SHAH

    2013-01-01

    Full Text Available The functional response types and parameters of 4th instar larvae, adult females and males ofcoccinellid predators, Adalia tetraspilota (Hope and Hippodamia variegata (Goeze were evaluatedat five different densities of Aphis pomi De Geer, Brevicoryne brassicae (Linnaeus and Aphis craccivoraKoch in order to understand the effect of predator species and stage, and prey species on functionalresponse and to understand their role for the aphids’ biological control. Experiments were carriedout in petri dishes at 25±2oC and 65±5% R.H. and 14L: 10D photoperiod in a controlled environmentroom. All tested stages exhibited a Type II response. The attack rate (a and handling time (Thcoefficients differed for various growth stages of each predator and for the three prey species tested.So did the parameter values for the two predators indicating that various predatory stages of apredator have different abilities to respond to increasing prey densities, so do the various predatorsfor a particular prey species and a particular predator towards various prey species. Attack ratecoefficients didn’t differ as much as the handling time, thus re-establishing the fact that handling timeis a good indicator of the effectiveness of a predator.

  12. Permanence and global attractivity of stage-structured predator-prey model with continuous harvesting on predator and impulsive stocking on prey

    Institute of Scientific and Technical Information of China (English)

    JIAO Jian-jun; CHEN Lan-sun; Juan J. Nieto; Torres Angela

    2008-01-01

    We investigate a stage-structured delayed predator-prey model with impulsive stocking on prey and continuous harvesting on predator. According to the fact of biological resource management, we improve the assumption of a predator-prey model with stage structure for predator population that each individual predator has the same ability to capture prey. It is assumed that the immature and mature individuals of the predator population are divided by a fixed age, and immature predator population does not have the ability to attach prey. Sufficient conditions are obtained, which guarantee the global attractivity of predator-extinction periodic solution and the permanence of the system. Our results show that the behavior of impulsive stocking on prey plays an important role for the permanence of the system, and provide tactical basis for the biological resource management. Numerical analysis is presented to illuminate the dynamics of the system.

  13. Exhaled breath analysis using electronic nose in cystic fibrosis and primary ciliary dyskinesia patients with chronic pulmonary infections

    DEFF Research Database (Denmark)

    Joensen, Odin; Paff, Tamara; Haarman, Eric G;

    2014-01-01

    The current diagnostic work-up and monitoring of pulmonary infections may be perceived as invasive, is time consuming and expensive. In this explorative study, we investigated whether or not a non-invasive exhaled breath analysis using an electronic nose would discriminate between cystic fibrosis...... (CF) and primary ciliary dyskinesia (PCD) with or without various well characterized chronic pulmonary infections. We recruited 64 patients with CF and 21 with PCD based on known chronic infection status. 21 healthy volunteers served as controls. An electronic nose was employed to analyze exhaled......, this method significantly discriminates CF patients suffering from a chronic pulmonary P. aeruginosa (PA) infection from CF patients without a chronic pulmonary infection. Further studies are needed for verification and to investigate the role of electronic nose technology in the very early diagnostic...

  14. Cross-talk between ciliary epithelium and trabecular meshwork cells in-vitro: a new insight into glaucoma.

    Directory of Open Access Journals (Sweden)

    Natalie Lerner

    Full Text Available PURPOSE: It is assumed that the non-pigmented ciliary epithelium plays a role in regulating intraocular pressure via its neuroendocrine activities. To test this hypothesis, we investigated the effect on a human trabecular meshwork (TM cell line (NTM of co-culture with a human non-pigmented ciliary epithelium cell line (ODM-2. METHODS: The cellular cross-talk between ODM-2 and NTM cells was studied in a co-culture system in which the two cell types were co-cultured for 5 to 60 min or 2, 4 and 8h and then removed from the co-culture and analyzed. Analyses of the ERK and p38 mitogen-activated protein kinase (MAPK pathways and of the activity of TM phosphatases and matrix metalloproteins (MMPs were performed. Acid and alkaline phosphatase activity was determined by the DiFMUP (6, 8-difluoro-4-methylumbelliferyl phosphate assay. MMP levels were determined by gelatin zymography. RESULTS: Exposure of NTM cells to ODM-2 cells led to the activation of the MAPK signal transduction pathways in NTM cells within 5 min of co-culture. Phosphorylation of ERK1/ERK2 and p38 peaked at 10 and 15 min and then decreased over time. Interaction between ODM-2 and NTM cells promoted the expression of MMP-9 in the NTM cells after 4h of co-culture. CONCLUSIONS: Our findings provide support for the hypothesis that crosstalk does indeed take place between ODM-2 and NTM cells. Future studies should be designed to determine the relationship between the MMP system, MAPK kinases and phosphatases. Manipulation of these signaling molecules and the related NTM signal transduction pathways may provide targets for developing improved treatments for glaucoma.

  15. Inhibitory Effect of Dexamethasone on TGF-β1 Expression of Rabbit Ciliary Pigment Epithelia Cultured in Vitro

    Institute of Scientific and Technical Information of China (English)

    XIONG Xinchun; XI Zulian; MIAO Juan; LI Qinglin; ZHANG Haijiang; HU Yizhen; WEI Houren

    2006-01-01

    In order to elucidate the effect of dexamethasone on the expression of transforming growth factor-beta1 (TGF-β1) in ciliary pigment epithelial (CPE) cells cultured in vitro, rabbit CPE cells were cultured in vitro, treated with DMEM medium containing 0,1×10-8 , 5×10-8 , 10 × 10-8 and 50×10-8 mol/L dexamethasone respectively for 5 days. The TGF-β1 expression was detected by immunohistochemistry Supervision methods and analyzed semi-quantitatively by HMIAS-2000 image system. As opposed to in vivo, rabbit CPE cells expressed TGF-β1 under cultured circumstance in vitro. The gray scales of the positive yellow staining in the groups of 1×10-8, 5×10-8, 10×10-8 and 50× 10-8 mol/L dexamethasone were 136. 57±4.43, 140. 20±6.10, 142.98±2. 99, 146. 80± 1.68 and 150. 05± 1.94 respectively. When the concentrations of dexamethasone were equal to or higher than 5×10-8 mol/L and, the expression of TGF-β1 was inhibited. 10-7 mol/L dexamethasone showed a significant inhibition. It was suggested that CPE cells possess the potential ability of synthesizing and expressing TGF-β1. The inhibition of TGF-β1 expression by dexamethasone may be beneficial to the treatment of proliferative vitroretinopathy, also exert some influence on the secretion of aqueous humor and ciliary inflammation.

  16. The development of the larval nervous system, musculature and ciliary bands of Pomatoceros lamarckii (Annelida: heterochrony in polychaetes

    Directory of Open Access Journals (Sweden)

    Shimeld Sebastian M

    2006-10-01

    Full Text Available Abstract Background To understand the evolution of animals it is essential to have taxon sampling across a representative spread of the animal kingdom. With the recent rearrangement of most of the Bilateria into three major clades (Ecdysozoa, Lophotrochozoa and Deuterostomia it has become clear that the Lophotrochozoa are relatively poorly represented in our knowledge of animal development, compared to the Ecdysozoa and Deuterostomia. We aim to contribute towards redressing this balance with data on the development of the muscular, nervous and ciliary systems of the annelid Pomatoceros lamarckii (Serpulidae. We compare our data with other lophotrochozoans. Results P. lamarckii develops locomotory and feeding structures that enable it to become a swimming, planktotrophic larva within 24 hours. Formation of the trochophore includes development of a prototroch, metatroch and neurotroch, development of apical and posterior nervous elements at similar times, and development of musculature around the ciliary bands and digestive tract prior to development of any body wall muscles. The adult nervous and muscular systems are essentially preformed in the late larva. Interestingly, the muscular systems of the larvae and juvenile worms do not include the circular muscles of the body wall, which are considered to be plesiomorphic for annelids, although the possibility that circular muscles develop after these stages cannot be ruled out at this point. Conclusion A comparison between polychaetes shows variability in the timing (heterochrony of development of body wall muscles and elements of the nervous system. These heterochronies are one route for evolution of different life history strategies, such as adaptations to feeding requirements.

  17. A delayed stage-structured Holling II predator-prey model with mutual interference and impulsive perturbations on predator

    International Nuclear Information System (INIS)

    In this work, we investigate a delayed stage-structured Holling II predator-prey model with mutual interference and impulsive perturbations on predator. Sufficient conditions of the global attractivity of prey-extinction periodic solution and the permanence of the system are obtained. We also prove that all solutions of the system are uniformly ultimately bounded. Our results provide reliable tactical basis for the practical pest management.

  18. Effects of climate and exurban development on nest predation and predator presence in the southern Appalachian Mountains (USA).

    Science.gov (United States)

    Lumpkin, Heather A; Pearson, Scott M; Turner, Monica G

    2012-08-01

    In the eastern United States, land-use and climate change have likely contributed to declines in the abundance of Neotropical migrant birds that occupy forest interiors, but the mechanisms are not well understood. We conducted a nest-predation experiment in southern Appalachian Mountain forests (North Carolina, U.S.A.) during the 2009 and 2010 breeding seasons to determine the effects of exurban development and temperature on predator presence and the average number of days until eggs in an artificial nest were disturbed by predators. We baited artificial nests with quail (Excalfactoria chinensi) eggs and monitored them for 18 days. We used clay eggs, track plates, and motion-triggered cameras to detect and identify nest predators. The average number of days a nest was undisturbed decreased as mean temperature increased and, to a lesser extent, as the density of buildings increased. Nests on the ground were more often depredated than those in trees, likely due to increased predation by opossum (Didelphis virginiana) and other carnivores. Raccoons (Procyon lotor), opossums, corvids (Corvus brachyrhynchos and Cyanocitta cristata), chipmunks (Tamias striatus), black bears (Ursus americanus), and domestic cats (Felis catus) were the most commonly detected predators. Presence of these predators did not vary as a function of mean temperature. Domestic cats and corvids were detected more frequently in plots with high rather than low densities of buildings. Forest-interior specialists and Neotropical migrants often nest in cool, high-elevation areas with low housing density. These bird species, especially those that nest on the ground, may be most vulnerable to increased nest predation if temperature and exurban development increase at higher elevations as anticipated. PMID:22624665

  19. Delayed stage-structured predator-prey model with impulsive perturbations on predator and chemical control on prey

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We consider a delayed stage-structured pest management predator-prey system with impulsive transmitting on predator and chemical control on prey. Sufficient conditions of the global attractiveness of the pest-extinction boundary periodic solution and permanence of the system are obtained. We also prove that all solutions of the system are uniformly ultimately bounded. Our results provide reliable tactical basis for practical pest management.

  20. Developing a predation index and evaluating ways to reduce salmonid losses to predation in the Columbia River basin

    International Nuclear Information System (INIS)

    We report our results of studies to develop a predation index and evaluate ways to reduce juvenile salmonid losses to predation in the Columbia River Basin. Study objectives of each were: develop an index to estimate predation losses of juvenile salmonids (Oncorhynchus spp) in reservoirs throughout the Columbia River Basin, describe the relationships among predator-caused mortality of juvenile salmonids and physical and biological variables, examine the feasibility of developing bounty, commercial or recreational fisheries on northern squawfish (Ptychocheilus oregonensis) and develop a plan to evaluate the efficacy of predator control fisheries; determine the economic feasibility of developing bounty and commercial fisheries for northern squawfish, assist ODFW with evaluating the economic feasibility of recreational fisheries for northern squawfish and assess the economic feasibility of utilizing northern squawfish, carp (Cyprinus carpio) and suckers (Castostomus spp) in multispecies fisheries; evaluate commercial technology of various fishing methods for harvesting northern squawfish in Columbia River reservoirs and field test the effectiveness of selected harvesting systems, holding facilities and transportation systems; and modify the existing Columbia River Ecosystem Model (CREM) to include processes necessary to evaluate effects of removing northern squawfish on their population size structure and abundance, document the ecological processes, mathematical equations and computer (FORTRAN) programming of the revised version of CREM and conduct systematic analyses of various predator removal scenarios, using revised CREM to generate the simulations. Individual reports are indexed separately

  1. Lithium treatment in ovo: effects on embryonic heart rate, natural death of ciliary ganglion neurons, and brain expression of a highly conserved chicken homolog of human MTG8/ETO.

    Science.gov (United States)

    Ikonomov, O C; Petrov, T; Soden, K; Shisheva, A; Manji, H K

    2000-09-30

    Understanding the action of the mood stabilizer lithium is dependent on availability of experimental models where lithium treatment at clinically relevant concentrations induces marked phenotypic and genotypic changes. Here we report on such changes in the chicken embryo. Lithium chloride (0.6 mM), applied in ovo 60 h after incubation, markedly delayed the heart rate increase observed from ED2.5 to ED5, and induced the brain expression of a new chicken gene cETO from ED7 to ED15. At the same time the overall developmental dynamics and embryo survival, or the expression of chicken gephyrin were not significantly affected. Furthermore, lithium treatment (0.3 mM, 48 h after incubation) abolished the difference in neuronal number between ED12 ciliary ganglia developing in the presence or absence of postganglionic target muscles. We show that cETO is a close homologue of the human transcription factor MTG8/ETO; named after its location on chromosome 8, and participation in chromosomal translocation 8;21 in myeloid leukemia. The mRNA and protein levels of ETO and gephyrin had a parallel course in chicken brain development suggesting that the expression of both genes is regulated mainly at the level of gene transcription. However, the patterns of expression were markedly different. ETO peaked at ED7 and decreased five-fold at ED15. In contrast, gephyrin levels increased five-fold from ED7 to ED15. We propose that the induction of ETO expression, in concert with lithium-induced upregulation of other genes, such as PEBP2beta and bcl-2, is participating in the neuroprotective effect of chronic lithium treatment. PMID:11020546

  2. Fish predation by semi-aquatic spiders: a global pattern.

    Science.gov (United States)

    Nyffeler, Martin; Pusey, Bradley J

    2014-01-01

    More than 80 incidences of fish predation by semi-aquatic spiders--observed at the fringes of shallow freshwater streams, rivers, lakes, ponds, swamps, and fens--are reviewed. We provide evidence that fish predation by semi-aquatic spiders is geographically widespread, occurring on all continents except Antarctica. Fish predation by spiders appears to be more common in warmer areas between 40° S and 40° N. The fish captured by spiders, usually ranging from 2-6 cm in length, are among the most common fish taxa occurring in their respective geographic area (e.g., mosquitofish [Gambusia spp.] in the southeastern USA, fish of the order Characiformes in the Neotropics, killifish [Aphyosemion spp.] in Central and West Africa, as well as Australian native fish of the genera Galaxias, Melanotaenia, and Pseudomugil). Naturally occurring fish predation has been witnessed in more than a dozen spider species from the superfamily Lycosoidea (families Pisauridae, Trechaleidae, and Lycosidae), in two species of the superfamily Ctenoidea (family Ctenidae), and in one species of the superfamily Corinnoidea (family Liocranidae). The majority of reports on fish predation by spiders referred to pisaurid spiders of the genera Dolomedes and Nilus (>75% of observed incidences). There is laboratory evidence that spiders from several more families (e.g., the water spider Argyroneta aquatica [Cybaeidae], the intertidal spider Desis marina [Desidae], and the 'swimming' huntsman spider Heteropoda natans [Sparassidae]) predate fish as well. Our finding of such a large diversity of spider families being engaged in fish predation is novel. Semi-aquatic spiders captured fish whose body length exceeded the spiders' body length (the captured fish being, on average, 2.2 times as long as the spiders). Evidence suggests that fish prey might be an occasional prey item of substantial nutritional importance. PMID:24940885

  3. Discrete cyclic di-GMP-dependent control of bacterial predation versus axenic growth in Bdellovibrio bacteriovorus.

    Directory of Open Access Journals (Sweden)

    Laura Hobley

    2012-02-01

    Full Text Available Bdellovibrio bacteriovorus is a Delta-proteobacterium that oscillates between free-living growth and predation on Gram-negative bacteria including important pathogens of man, animals and plants. After entering the prey periplasm, killing the prey and replicating inside the prey bdelloplast, several motile B. bacteriovorus progeny cells emerge. The B. bacteriovorus HD100 genome encodes numerous proteins predicted to be involved in signalling via the secondary messenger cyclic di-GMP (c-di-GMP, which is known to affect bacterial lifestyle choices. We investigated the role of c-di-GMP signalling in B. bacteriovorus, focussing on the five GGDEF domain proteins that are predicted to function as diguanylyl cyclases initiating c-di-GMP signalling cascades. Inactivation of individual GGDEF domain genes resulted in remarkably distinct phenotypes. Deletion of dgcB (Bd0742 resulted in a predation impaired, obligately axenic mutant, while deletion of dgcC (Bd1434 resulted in the opposite, obligately predatory mutant. Deletion of dgcA (Bd0367 abolished gliding motility, producing bacteria capable of predatory invasion but unable to leave the exhausted prey. Complementation was achieved with wild type dgc genes, but not with GGAAF versions. Deletion of cdgA (Bd3125 substantially slowed predation; this was restored by wild type complementation. Deletion of dgcD (Bd3766 had no observable phenotype. In vitro assays showed that DgcA, DgcB, and DgcC were diguanylyl cyclases. CdgA lacks enzymatic activity but functions as a c-di-GMP receptor apparently in the DgcB pathway. Activity of DgcD was not detected. Deletion of DgcA strongly decreased the extractable c-di-GMP content of axenic Bdellovibrio cells. We show that c-di-GMP signalling pathways are essential for both the free-living and predatory lifestyles of B. bacteriovorus and that obligately predatory dgcC- can be made lacking a propensity to survive without predation of bacterial pathogens and thus possibly

  4. High trees increase sunflower seed predation by birds in an agricultural landscape of Israel

    Directory of Open Access Journals (Sweden)

    JessicaSchäckermann

    2014-07-01

    We found that seed predation increased with decreasing distance to the closest high tree at the field and landscape scale. At the landscape scale, the percentage of high trees and natural habitat did not increase seed predation. Seed predation in the fields increased by 37 %, with a maximum seed predation of 92 %, when a high tree was available within zero to 50 m to the sunflower fields. If the closest high tree was further away, seed predation was less than 5 %. Sunflower seed predation by birds can be reduced, when avoiding sowing sunflowers within a radius of 50 m to high trees. Farmers should plan to grow crops, not sensitive to bird seed predation, closer to trees to eventually benefit from ecosystem services provided by birds, such as predation of pest insects, while avoiding these locations for growing crops sensitive to bird seed predation. Such management recommendations are directing towards sustainable agricultural landscapes.

  5. Landscape genetics of a top neotropical predator.

    Science.gov (United States)

    Pérez-Espona, S; McLeod, J E; Franks, N R

    2012-12-01

    Habitat loss and fragmentation as a consequence of human activities is a worldwide phenomenon and one of the major threats to global biodiversity. Habitat loss and fragmentation is particularly a concern in the biodiverse tropics, where deforestation is occurring at unprecedented rates. Although insects are one of the most diverse and functionally important groups in tropical ecosystems, the quantitative effect of landscape features on their gene flow remains unknown. Here, we used a robust landscape genetics approach to quantify the effect of ten landscape features (deforestation, mature forests, other forest types, the River Chagres, streams, stream banks, roads, sea, lakes and swamps) and interactions between them, on the gene flow of a neotropical forest keystone species, the army ant Eciton burchellii. The influence of landscape on E. burchellii's gene flow reflected the different dispersal capability of its sexes; aerial for males and pedestrian for females, and the different depths of population history inferred from microsatellites and mitochondrial DNA. In contrast to the gene flow-facilitating effect of mature forests, deforested areas were found to be strong barriers for E. burchellii's gene flow. Other forest types were found to be gene flow facilitators but only when interacting with mature secondary forests, therefore indicating the importance of mature forests for the survival of E. burchelii and its associate species. The River Chagres was identified as a major historical gene flow barrier for E. burchellii, suggesting that an important loss of connectivity may occur because of large artificial waterways such as the Panama Canal. PMID:23110496

  6. An exploitation-competition system with negative effect of prey on its predator.

    Science.gov (United States)

    Wang, Yuanshi

    2015-05-01

    This paper considers an exploitation-competition system in which exploitation is the dominant interaction when the prey is at low density, while competition is dominant when the prey is at high density due to its negative effect on the predator. The two-species system is characterized by differential equations, which are the combination of Lotka-Volterra competitive and predator-prey models. Global dynamics of the model demonstrate some basic properties of exploitation-competition systems: (i) When the growth rate of prey is extremely small, the prey cannot promote the growth of predator. (ii) When the growth rate is small, an obligate predator can survive by preying on the prey, while a facultative predator can approach a high density by the predation. (iii) When the growth rate is intermediate, the predator can approach the maximal density by an intermediate predation. (iv) When the growth rate is large, the predator can persist only if it has a large density and its predation on the prey is big. (v) Intermediate predation is beneficial to the predator under certain parameter range, while over- or under-predation is not good. Extremely big/small predation would lead to extinction of species. Numerical simulations confirm and extend our results. PMID:25707917

  7. Effects of an infectious fungus, Batrachochytrium dendrobatidis, on amphibian predator-prey interactions.

    Directory of Open Access Journals (Sweden)

    Barbara A Han

    Full Text Available The effects of parasites and pathogens on host behaviors may be particularly important in predator-prey contexts, since few animal behaviors are more crucial for ensuring immediate survival than the avoidance of lethal predators in nature. We examined the effects of an emerging fungal pathogen of amphibians, Batrachochytrium dendrobatidis, on anti-predator behaviors of tadpoles of four frog species. We also investigated whether amphibian predators consumed infected prey, and whether B. dendrobatidis caused differences in predation rates among prey in laboratory feeding trials. We found differences in anti-predator behaviors among larvae of four amphibian species, and show that infected tadpoles of one species (Anaxyrus boreas were more active and sought refuge more frequently when exposed to predator chemical cues. Salamander predators consumed infected and uninfected tadpoles of three other prey species at similar rates in feeding trials, and predation risk among prey was unaffected by B. dendrobatidis. Collectively, our results show that even sub-lethal exposure to B. dendrobatidis can alter fundamental anti-predator behaviors in some amphibian prey species, and suggest the unexplored possibility that indiscriminate predation between infected and uninfected prey (i.e., non-selective predation could increase the prevalence of this widely distributed pathogen in amphibian populations. Because one of the most prominent types of predators in many amphibian systems is salamanders, and because salamanders are susceptible to B. dendrobatidis, our work suggests the importance of considering host susceptibility and behavioral changes that could arise from infection in both predators and prey.

  8. Molecular Markers Detect Cryptic Predation on Coffee Berry Borer (Coleoptera: Curculionidae) by Silvanid and Laemophloeid Flat Bark Beetles (Coleoptera: Silvanidae, Laemophloeidae) in Coffee Beans.

    Science.gov (United States)

    Sim, Sheina B; Yoneishi, Nicole M; Brill, Eva; Geib, Scott M; Follett, Peter A

    2016-02-01

    The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae), is a serious pest of coffee worldwide. It was first detected in Hawai'i in 2010. Two predatory beetles, Cathartus quadricollis (Coleoptera: Silvanidae) and Leptophloeus sp. (Coleoptera: Laemophloeidae), have been observed in H. hampei-infested coffee. Under laboratory conditions, colony-reared C. quadricollis and Leptophloeus sp. prey upon all life stages of H. hampei. However, the H. hampei life cycle occurs almost exclusively within a coffee bean obscured from direct observation. Thus, it is unknown if C. quadricollis and Leptophloeus sp. consume H. hampei as prey in the wild. To demonstrate predation of H. hampei by C. quadricollis and Leptophloeus sp., a molecular assay was developed utilizing species-specific primers targeting short regions of the mitochondrial COI gene to determine species presence. Using these primers, wild C. quadricollis and Leptophloeus sp. were collected and screened for the presence of H. hampei DNA using PCR. Analysis of collections from five coffee farms revealed predation of C. quadricollis and Leptophloeus sp. on H. hampei. Further laboratory testing showed that H. hampei DNA could be detected in predators for as long as 48 h after feeding, indicating the farm-caught predators had preyed on H. hampei within 2 d of sampling. This study demonstrates the utility of molecular markers for the study of the ecology of predators and prey with cryptic behavior, and suggests C. quadricollis and Leptophloeus sp. might be useful biocontrol agents against H. hampei. PMID:26487745

  9. Predation, Competition, and Abiotic Disturbance: Population Dynamics of Small Mammals

    Energy Technology Data Exchange (ETDEWEB)

    Yunger, John A.; /Northern Illinois U. /Northern Illinois U.

    1996-01-01

    Predation and food availability have been implicated in annual non-cyclic fluctuations of vertebrate prey at mid-latitudes. The timing and magnitude of these factors are unclear due to a lack of large-scale field experiments, little attention to interactions, and a failure to closely link vertebrate predators with their prey. From October 1992 to January 1996, small mammal populations were censused on eight 0.6 ha plots at monthly intervals in a 32-ha prairie restoration at Fermi National Accelerator Laboratory, Illinois. Terrestrial vertebrate predators were excluded after July 1993 from four of the eight plots and canid diets monitored. Both terrestrial and avian vertebrate predators were excluded in March 1994. During 1993 small mammal densities (i.e., Microtus Pennsylvanicus, Peromyscus leucopus, and P. maniculatus) were relatively high. Following peak densities in late summer, Microtus numbers wer 2-3x greater on exclusion plots relative to controls due to preferential selection of Microtus by canids, as reflected in dits. Following an ice-storm and crash in small mammal numbers (particularly Microtus), vertebrate predator exclusion had no detectable effect on P. leucopus numbers, probably due to an abundance of alternative prey (i.e., Sylvilagus floridanus). Meadow vole numbers began to increase in Fall 1995, and a numerical effect of predator exclusion, similar to that in 1993, was observed. Predator exclusion had no detectable effect on the movements and spatial patterns of Microtus during 1993. There was a significant decrease in home range and a significant increase in home range overlap for P. leucopus on the predator exclusion plots. The change in spatial behavior may be due to interspecific competition with Microtus resulting from increased densities on exclusion plots. Thus, predators had an indirect effect on P. leucopus spatial patterns mediated through M. Pennsylvanicus. The role of food limitation was studied using natural and manipulative

  10. Reconciling actual and perceived rates of predation by domestic cats

    Science.gov (United States)

    McDonald, Jennifer L; Maclean, Mairead; Evans, Matthew R; Hodgson, Dave J

    2015-01-01

    The predation of wildlife by domestic cats (Felis catus) is a complex problem: Cats are popular companion animals in modern society but are also acknowledged predators of birds, herpetofauna, invertebrates, and small mammals. A comprehensive understanding of this conservation issue demands an understanding of both the ecological consequence of owning a domestic cat and the attitudes of cat owners. Here, we determine whether cat owners are aware of the predatory behavior of their cats, using data collected from 86 cats in two UK villages. We examine whether the amount of prey their cat returns influences the attitudes of 45 cat owners toward the broader issue of domestic cat predation. We also contribute to the wider understanding of physiological, spatial, and behavioral drivers of prey returns among cats. We find an association between actual prey returns and owner predictions at the coarse scale of predatory/nonpredatory behavior, but no correlation between the observed and predicted prey-return rates among predatory cats. Cat owners generally disagreed with the statement that cats are harmful to wildlife, and disfavored all mitigation options apart from neutering. These attitudes were uncorrelated with the predatory behavior of their cats. Cat owners failed to perceive the magnitude of their cats’ impacts on wildlife and were not influenced by ecological information. Management options for the mitigation of cat predation appear unlikely to work if they focus on “predation awareness” campaigns or restrictions of cat freedom. PMID:26306163

  11. Integrating environmental variation, predation pressure, phenotypic plasticity and locomotor performance.

    Science.gov (United States)

    Fu, Shi-Jian; Cao, Zhen-Dong; Yan, Guan-Jie; Fu, Cheng; Pang, Xu

    2013-10-01

    The Wujiang River, a tributary of the Three Gorges Reservoir, has many dams along its length. These dams alter the river's natural habitat and produce various flow regimes and degrees of predator stress. To test whether the swimming performance and external body shape of pale chub (Zacco platypus) have changed as a result of alterations in the flow regime and predator conditions, we measured the steady (U(crit)) and unsteady (fast-start) swimming performances and morphological characteristics of fish collected from different sites along the Wujiang River. We also calculated the maximum respiratory capacity and cost of transport (COT). We demonstrated significant differences in swimming performance and morphological traits among the sampling sites. Steady swimming performance was positively correlated with water velocity and negatively correlated with the abundance of predators, whereas unsteady swimming performance was negatively correlated with water velocity. The body shape was significantly correlated with both swimming performance and ecological parameters. These findings suggested that selection pressure on swimming performance results in a higher U(crit) and a more streamlined body shape in fast-flow and (or) in habitats with low predator stress and subsequently results in a lower COT. These characteristics were accompanied by a poorer fast-start performance than that of the fish from the slow-flow and (or) high-predator habitats. The divergence in U(crit) may also be due in part to variation in respiratory capacity. PMID:23463244

  12. Predator facilitation or interference: a game of vipers and owls.

    Science.gov (United States)

    Embar, Keren; Raveh, Ashael; Hoffmann, Ishai; Kotler, Burt P

    2014-04-01

    In predator-prey foraging games, the prey's reaction to one type of predator may either facilitate or hinder the success of another predator. We ask, do different predator species affect each other's patch selection? If the predators facilitate each other, they should prefer to hunt in the same patch; if they interfere, they should prefer to hunt alone. We performed an experiment in a large outdoor vivarium where we presented barn owls (Tyto alba) with a choice of hunting greater Egyptian gerbils (Gerbillus pyramidum) in patches with or without Saharan horned vipers (Cerastes cerastes). Gerbils foraged on feeding trays set under bushes or in the open. We monitored owl location, activity, and hunting attempts, viper activity and ambush site location, and the foraging behavior of the gerbils in bush and open microhabitats. Owls directed more attacks towards patches with vipers, and vipers were more active in the presence of owls. Owls and vipers facilitated each other's hunting through their combined effect on gerbil behavior, especially on full moon nights when vipers are more active. Owls forced gerbils into the bushes where vipers preferred to ambush, while viper presence chased gerbils into the open where they were exposed to owls. Owls and vipers took advantage of their indirect positive effect on each other. In the foraging game context, they improve each other's patch quality and hunting success. PMID:24481981

  13. Reconciling actual and perceived rates of predation by domestic cats.

    Science.gov (United States)

    McDonald, Jennifer L; Maclean, Mairead; Evans, Matthew R; Hodgson, Dave J

    2015-07-01

    The predation of wildlife by domestic cats (Felis catus) is a complex problem: Cats are popular companion animals in modern society but are also acknowledged predators of birds, herpetofauna, invertebrates, and small mammals. A comprehensive understanding of this conservation issue demands an understanding of both the ecological consequence of owning a domestic cat and the attitudes of cat owners. Here, we determine whether cat owners are aware of the predatory behavior of their cats, using data collected from 86 cats in two UK villages. We examine whether the amount of prey their cat returns influences the attitudes of 45 cat owners toward the broader issue of domestic cat predation. We also contribute to the wider understanding of physiological, spatial, and behavioral drivers of prey returns among cats. We find an association between actual prey returns and owner predictions at the coarse scale of predatory/nonpredatory behavior, but no correlation between the observed and predicted prey-return rates among predatory cats. Cat owners generally disagreed with the statement that cats are harmful to wildlife, and disfavored all mitigation options apart from neutering. These attitudes were uncorrelated with the predatory behavior of their cats. Cat owners failed to perceive the magnitude of their cats' impacts on wildlife and were not influenced by ecological information. Management options for the mitigation of cat predation appear unlikely to work if they focus on "predation awareness" campaigns or restrictions of cat freedom. PMID:26306163

  14. Role of seasonality on predator-prey-subsidy population dynamics.

    Science.gov (United States)

    Levy, Dorian; Harrington, Heather A; Van Gorder, Robert A

    2016-05-01

    The role of seasonality on predator-prey interactions in the presence of a resource subsidy is examined using a system of non-autonomous ordinary differential equations (ODEs). The problem is motivated by the Arctic, inhabited by the ecological system of arctic foxes (predator), lemmings (prey), and seal carrion (subsidy). We construct two nonlinear, nonautonomous systems of ODEs named the Primary Model, and the n-Patch Model. The Primary Model considers spatial factors implicitly, and the n-Patch Model considers space explicitly as a "Stepping Stone" system. We establish the boundedness of the dynamics, as well as the necessity of sufficiently nutritional food for the survival of the predator. We investigate the importance of including the resource subsidy explicitly in the model, and the importance of accounting for predator mortality during migration. We find a variety of non-equilibrium dynamics for both systems, obtaining both limit cycles and chaotic oscillations. We were then able to discuss relevant implications for biologically interesting predator-prey systems including subsidy under seasonal effects. Notably, we can observe the extinction or persistence of a species when the corresponding autonomous system might predict the opposite. PMID:26916622

  15. Impacts of Size Structure on Intraguild Predation in Pond Communities

    Science.gov (United States)

    Crumrine, P. W.

    2005-05-01

    Size structure, the degree to which individuals in a population vary in size, can greatly influence the dynamics of intraguild predation (IGP) within ecological communities. I manipulated the degree of size structure within assemblages of IG predators and IG prey to examine impacts on the direction and intensity of IGP in communities of larval dragonflies and larval water beetles. In pond enclosure studies, Pachydiplax longipennis (IG prey) mortality was lower when exposed to size structured assemblages of Anax junius (IG predator) than when exposed to only large A. junius at the same density. Effects of size-structured assemblages of A. junius on shared prey, Ischnura verticalis, were similar to the effects each size class alone at the same density. Separate experiments with Dytiscid water beetle larvae as IG predators and size-structured assemblages of A. junius as IG prey suggest that IG prey size structure plays only a limited role in mediating shared prey survival. These experiments highlight the importance of size structure as a characteristic that may promote the coexistence of predators in IGP systems.

  16. Effects of predation by Hydra (Cnidaria on cladocerans (Crustacea: Cladocera

    Directory of Open Access Journals (Sweden)

    Ligia Rivera-De la Parra

    2016-03-01

    Full Text Available Planktonic cladocerans have evolved different strategies to avoid predation from vertebrates; these include changes in morphology, behavior, physiology, and/or life-history traits. However, littoral cladocerans are better adapted to avoid invertebrate predation particularly from insect larvae by evolving morphological and physiological adaptations. Nevertheless, this has not been proven for some littoral predators such as Hydra. In this study, we provide quantitative data on how Hydra affects its zooplankton prey. We studied the predation behavior on Alona glabra, Ceridodaphnia dubia, Daphnia pulex, Daphnia cf. mendotae, Diaphanosoma birgei, Macrothrix triserialis, Moina macrocopa, Pleuroxus aduncus, Scapholeberis kingi, Simocephalus vetulus, Elaphoidella grandidieri, Brachionus rubens and Euchlanis dilatata. We also tested the indirect effect of allelochemicals from Hydra on the demography of Daphnia cf. mendotae. Littoral cladocerans are specially adapted to resist nematocyst injection and discharge of toxic substances from Hydra. A significant decrease in the population growth rate from 0.21 to 0.125 d-1 was observed at densities of 2 ind. ml-1. The role of carapace thickness as an adaptive strategy of littoral cladocerans against Hydra predation is discussed.

  17. Predation rate by wolves on the Porcupine caribou herd

    Directory of Open Access Journals (Sweden)

    Robert D. Hayes

    2000-04-01

    Full Text Available Large migratory catibou {Rangifer tarandus herds in the Arctic tend to be cyclic, and population trends are mainly driven by changes in forage or weather events, not by predation. We estimated daily kill rate by wolves on adult caribou in winter, then constructed a time and space dependent model to estimate annual wolf (Canis lupus predation rate (P annual on adult Porcupine caribou. Our model adjusts predation seasonally depending on caribou distribution: Pannual = SIGMAdaily* W *Ap(2*Dp. In our model we assumed that wolves killed adult caribou at a constant rate (Kdaily, 0.08 caribou wolf1 day1 based on our studies and elsewhere; that wolf density (W doubled to 6 wolves 1000 km2-1 on all seasonal ranges; and that the average area occupied by the Porcupine caribou herd (PCH in eight seasonal life cycle periods (Dp was two times gteater than the area described by the outer boundaries of telemetry data (Ap /1000 km2. Results from our model projected that wolves kill about 7600 adult caribou each year, regardless of herd size. The model estimated that wolves removed 5.8 to 7.4% of adult caribou as the herd declined in the 1990s. Our predation rate model supports the hypothesis of Bergerud that spacing away by caribou is an effective anti-predatory strategy that greatly reduces wolf predation on adult caribou in the spring and summer.

  18. Predators help protect carbon stocks in blue carbon ecosystems

    Science.gov (United States)

    Atwood, Trisha B.; Connolly, Rod M.; Ritchie, Euan G.; Lovelock, Catherine E.; Heithaus, Michael R.; Hays, Graeme C.; Fourqurean, James W.; Macreadie, Peter I.

    2015-12-01

    Predators continue to be harvested unsustainably throughout most of the Earth's ecosystems. Recent research demonstrates that the functional loss of predators could have far-reaching consequences on carbon cycling and, by implication, our ability to ameliorate climate change impacts. Yet the influence of predators on carbon accumulation and preservation in vegetated coastal habitats (that is, salt marshes, seagrass meadows and mangroves) is poorly understood, despite these being some of the Earth's most vulnerable and carbon-rich ecosystems. Here we discuss potential pathways by which trophic downgrading affects carbon capture, accumulation and preservation in vegetated coastal habitats. We identify an urgent need for further research on the influence of predators on carbon cycling in vegetated coastal habitats, and ultimately the role that these systems play in climate change mitigation. There is, however, sufficient evidence to suggest that intact predator populations are critical to maintaining or growing reserves of 'blue carbon' (carbon stored in coastal or marine ecosystems), and policy and management need to be improved to reflect these realities.

  19. Preliminary testing of the role of exercise and predator recognition for bonytail and razorback sucker

    Science.gov (United States)

    Mueller, Gordon A.; Carpenter, Jeanette; Krapfel, Robert; Figiel, Chester

    2007-01-01

    Hatchery-reared juvenile, 45-cm TL) flathead catfish. Predator-naïve juveniles (20- to 25-cm TL) exhibited no discernable preference when provided areas with and without (52 percent and 48 percent, n = 16 observations; 46 percent and 54 percent, n = 20 observations) large flathead catfish. However, once predation occurred, use of predator-free areas nearly doubled in two trials (36 percent and 64 percent, n = 50 observations; 33 percent and 67 percent, n = 12 observations). A more stringent test examining available area indicated predator-savvy razorback suckers used predator-free areas (88 percent, n = 21) illustrating predator avoidance was a learned behavior.

  20. Pathogenesis of Congenital Rubella Virus Infection in Human Fetuses: Viral Infection in the Ciliary Body Could Play an Important Role in Cataractogenesis

    Directory of Open Access Journals (Sweden)

    Thong Van Nguyen

    2015-01-01

    Interpretation: Our study based on the pathological examination demonstrated that the rubella virus infection occurred via systemic organs of human fetuses. This fact was confirmed by immunohistochemistry and direct detection of viral RNA in multiple organs. To the best of our knowledge, this study is the first report demonstrating that the rubella virus infection occurred via systemic organs of the human body. Importantly, virus infection of the ciliary body could play an important role in cataractogenesis.

  1. The ciliary neurotrophic factor receptor α component induces the secretion of and is required for functional responses to cardiotrophin-like cytokine

    OpenAIRE

    Plun-Favreau, Hélène; Elson, Greg; Chabbert, Marie; Froger, Josy; deLapeyrière, Odile; Lelièvre, Eric; Guillet, Catherine; Hermann, Jacques; Gauchat, Jean-François; Gascan, Hugues; Chevalier, Sylvie

    2001-01-01

    Ciliary neurotrophic factor (CNTF) is involved in the survival of a number of different neural cell types, including motor neurons. CNTF functional responses are mediated through a tripartite membrane receptor composed of two signalling receptor chains, gp130 and the leukaemia inhibitory factor receptor (LIFR), associated with a non-signalling CNTF binding receptor α component (CNTFR). CNTFR-deficient mice show profound neuronal deficits at birth, leading to a lethal phenotype. In contrast, i...

  2. Ciliary Neurotrophic Factor Promotes the Migration of Corneal Epithelial Stem/progenitor Cells by Up-regulation of MMPs through the Phosphorylation of Akt

    OpenAIRE

    Chen, Jialin; Chen, Peng; Backman, Ludvig J; Zhou, Qingjun; Danielson, Patrik

    2016-01-01

    The migration of limbal epithelial stem cells is important for the homeostasis and regeneration of corneal epithelium. Ciliary neurotrophic factor (CNTF) has been found to promote corneal epithelial wound healing by activating corneal epithelial stem/progenitor cells. However, the possible effect of CNTF on the migration of corneal epithelial stem/progenitor cells is not clear. This study found the expression of CNTF in mouse corneal epithelial stem/progenitor cells (TKE2) to be up-regulated ...

  3. Ciliary neurotrophic factor (CNTF) plus soluble CNTF receptor α increases cyclooxygenase-2 expression, PGE2 release and interferon-γ-induced CD40 in murine microglia

    OpenAIRE

    Li Hong; Jain Mohit; Lin Hsiao-Wen; Levison Steven W

    2009-01-01

    Abstract Background Ciliary neurotrophic factor (CNTF) has been regarded as a potent trophic factor for motor neurons. However, recent studies have shown that CNTF exerts effects on glial cells as well as neurons. For instance, CNTF stimulates astrocytes to secrete FGF-2 and rat microglia to secrete glial cell line-derived neurotrophic factor (GDNF), which suggest that CNTF exerts effects on astrocytes and microglia to promote motor neuron survival indirectly. As CNTF is structurally related ...

  4. Sortilin Facilitates Signaling of Ciliary Neurotrophic Factor and Related Helical Type 1 Cytokines Targeting the gp130/Leukemia Inhibitory Factor Receptor β Heterodimer ▿

    OpenAIRE

    Larsen, Jakob Vejby; Hansen, Maria; Møller, Bjarne; Madsen, Peder; SCHELLER, JÜRGEN; Nielsen, Morten; Petersen, Claus Munck

    2010-01-01

    Sortilin is a member of the Vps10p domain family of neuropeptide and neurotrophin binding neuronal receptors. The family members interact with and partly share a variety of ligands and partake in intracellular sorting and protein transport as well as in transmembrane signal transduction. Thus, sortilin mediates the transport of both neurotensin and nerve growth factor and interacts with their respective receptors to facilitate ligand-induced signaling. Here we report that ciliary neurotrophic...

  5. Ciliary neurotrophic factor inhibits brain and peripheral tumor necrosis factor production and, when coadministered with its soluble receptor, protects mice from lipopolysaccharide toxicity.

    OpenAIRE

    Benigni, F; Villa, P.; Demitri, M. T.; S. Sacco; Sipe, J. D.; Lagunowich, L.; Panayotatos, N; Ghezzi, P

    1995-01-01

    BACKGROUND: The receptor of ciliary neurotrophic factor (CNTF) contains the signal transduction protein gp130, which is also a component of the receptors of cytokines such as interleukin (IL)-6, leukemia-inhibitory factor (LIF), IL-11, and oncostatin M. This suggests that these cytokines might share common signaling pathways. We previously reported that CNTF augments the levels of corticosterone (CS) and of IL-6 induced by IL-1 and induces the production of the acute-phase protein serum amylo...

  6. Proliferative responses and binding properties of hematopoietic cells transfected with low-affinity receptors for leukemia inhibitory factor, oncostatin M, and ciliary neurotrophic factor.

    OpenAIRE

    Gearing, D P; Ziegler, S F; Comeau, M R; Friend, D; Thoma, B; Cosman, D; Park, L.; Mosley, B

    1994-01-01

    Specific low-affinity receptors for leukemia inhibitory factor (LIF), oncostatin M (OSM; gp130), and ciliary neurotrophic factor (CNTF; receptor alpha, CNTFR alpha) may be utilized in various combinations to generate high-affinity binding sites and signal transduction. We have tested the ability of combinations of these receptors to transduce a proliferative signal in BAF-B03 cells. Coexpression of the LIF receptor and gp130 in these cells conferred high-affinity LIF and OSM binding and respo...

  7. Susceptibility of Select Agents to Predation by Predatory Bacteria

    Directory of Open Access Journals (Sweden)

    Riccardo Russo

    2015-12-01

    Full Text Available Select Agents are microorganisms and toxins considered to be exploitable as biological weapons. Although infections by many Select Agents can be treated by conventional antibiotics, the risk of an emerging or engineered drug resistant strain is of great concern. One group of microorganisms that is showing potential to control drug resistant Gram-negative bacteria are the predatory bacteria from the genera Bdellovibrio spp. and Micavibrio spp. In this study, we have examined the ability of Bdellovibrio bacteriovorus (B. bacteriovorus strain 109J, HD100 and Micavibrio aeruginosavorus (M. aeruginosavorus ARL-13 to prey on a variety of Select Agents. Our findings demonstrate that B. bacteriovorus and M. aeruginosavorus are able to prey efficiently on Yersinia pestis and Burkholderia mallei. Modest predation was also measured in co-cultures of B. bacteriovorus and Francisella tularensis. However, neither of the predators showed predation when Burkholderia pseudomallei and Brucella melitensis were used as prey.

  8. Effects of random habitat destruction in a predator prey model

    Science.gov (United States)

    Szwabiński, Janusz; Peķalski, Andrzej

    2006-01-01

    The influence of habitat destruction on a population of predators and prey is studied. We show, via Monte Carlo simulations of a lattice model, that with growing devastation the oscillations in the densities of both species, as well as cross-correlations between the two densities diminish. As should be expected, predators are more vulnerable and disappear before the prey. Devastation of the habitat is never beneficial and the percentage of coexisting (prey and predators) states decreases with destruction. Because of the high fragmentation of the environment in the case of large devastation, animals’ populations are separated into small sub-populations living in restricted areas. Such small populations become extinct more easily. We have also shown that in the case of large habitat devastation the density of the population of prey depends on its history.

  9. Persistence in nonautonomous predator-prey systems with infinite delays

    Science.gov (United States)

    Teng, Zhidong; Rehim, Mehbuba

    2006-12-01

    This paper studies the general nonautonomous predator-prey Lotka-Volterra systems with infinite delays. The sufficient and necessary conditions of integrable form on the permanence and persistence of species are established. A very interesting and important property of two-species predator-prey systems is discovered, that is, the permanence of species and the existence of a persistent solution are each other equivalent. Particularly, for the periodic system with delays, applying these results, the sufficient and necessary conditions on the permanence and the existence of positive periodic solutions are obtained. Some well-known results on the nondelayed periodic predator-prey Lotka-Volterra systems are strongly improved and extended to the delayed case.

  10. Predator and prey perception in copepods due to hydromechanical signals

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Visser, Andre

    1999-01-01

    (deformation rate, vorticity, acceleration) generated by the predator. On the assumption that hydrodynamic disturbances are perceived through the mechanical bending of sensory setae, we estimate the magnitude of the signal strength due to each of the fluid disturbance components. We then derive equations for......Copepods can perceive moving predators and prey by means of the hydrodynamical disturbances these generate. We formulate a simplified, general model of the fluid disturbance generated by a plankter that is moving or generating a feeding current and we estimate the magnitude and attenuation of the...... different components of the fluid disturbance. We use this model to argue that prey perception depends on the absolute magnitude of the fluid velocity generated by the moving prey, while predator perception depends on the magnitude of one or several of the components of the fluid velocity gradients...

  11. New parasitoid-predator associations: female parasitoids do not avoid competition with generalist predators when sharing invasive prey

    Science.gov (United States)

    Chailleux, Anaïs; Wajnberg, Eric; Zhou, Yuxiang; Amiens-Desneux, Edwige; Desneux, Nicolas

    2014-12-01

    Optimal habitat selection is essential for species survival in ecosystems, and interspecific competition is a key ecological mechanism for many observed species association patterns. Specialized animal species are commonly affected by resource and interference competition with generalist and/or omnivorous competitors, so avoidance behavior could be expected. We hypothesize that specialist species may exploit broad range cues from such potential resource competitors (i.e., cues possibly common to various generalist and/or omnivorous predators) to avoid costly competition regarding food or reproduction, even in new species associations. We tested this hypothesis by studying short-term interactions between a native larval parasitoid and a native generalist omnivorous predator recently sharing the same invasive host/prey, the leaf miner Tuta absoluta. We observed a strong negative effect of kleptoparasitism (food resource stealing) instead of classical intraguild predation on immature parasitoids. There was no evidence that parasitoid females avoided the omnivorous predator when searching for oviposition sites, although we studied both long- and short-range known detection mechanisms. Therefore, we conclude that broad range cue avoidance may not exist in our biological system, probably because it would lead to too much oviposition site avoidance which would not be an efficient and, thus, beneficial strategy. If confirmed in other parasitoids or specialist predators, our findings may have implications for population dynamics, especially in the current context of increasing invasive species and the resulting creation of many new species associations.

  12. Predation risk-mediated maternal effects in the two-spotted spider mite, Tetranychus urticae.

    Science.gov (United States)

    Freinschlag, Julia; Schausberger, Peter

    2016-05-01

    Predation risk is a strong selective force shaping prey morphology, physiology, life history and/or behavior. As a prime stressor, predation risk may even induce trans-generational alterations, called maternal effects. Accordingly, maternal predation risk during offspring production may influence offspring life history and anti-predator behavior. Here, we assessed whether different levels of predation risk, posed by the predatory mite Phytoseiulus persimilis, induce graded maternal effects in its prey, the herbivorous two-spotted spider mite Tetranychus urticae. First, we generated four types of predation risk-stressed spider mite mothers by exposing them to living predators, direct and indirect predator cue combinations or no predator cues, respectively. Then, we investigated the life history (offspring developmental time, sex) and anti-predator response (activity, position on the leaf) of their offspring on leaves with and without direct and indirect predator cues. Maternal stress, no matter of the predation risk level, prolonged the offspring developmental time, as compared to offspring from unstressed mothers. This pattern was more pronounced on leaves with than without predator cues. Offspring from stressed mothers resided more likely on the leaf blade than close to the leaf vein. Offspring sex ratio and activity were not influenced by maternal predation risk but activity was higher on leaves with than without predator cues. We argue that the prolonged developmental time is non-adaptive, yet the changed site preference is adaptive because reducing the encounter likelihood with predators. Our study represents a key example for predation risk-mediated maternal effects on developmental trajectories of offspring. PMID:26923463

  13. Does predation risk affect mating behavior? An experimental test in dumpling squid (Euprymna tasmanica.

    Directory of Open Access Journals (Sweden)

    Amanda M Franklin

    Full Text Available INTRODUCTION: One of the most important trade-offs for many animals is that between survival and reproduction. This is particularly apparent when mating increases the risk of predation, either by increasing conspicuousness, reducing mobility or inhibiting an individual's ability to detect predators. Individuals may mitigate the risk of predation by altering their reproductive behavior (e.g. increasing anti-predator responses to reduce conspicuousness. The degree to which individuals modulate their reproductive behavior in relation to predation risk is difficult to predict because both the optimal investment in current and future reproduction (due to life-history strategies and level of predation risk may differ between the sexes and among species. Here, we investigate the effect of increased predation risk on the reproductive behavior of dumpling squid (Euprymna tasmanica. RESULTS: Females, but not males, showed a substantial increase in the number of inks (an anti-predator behavior before mating commenced in the presence of a predator (sand flathead Platycephalus bassensis. However, predation risk did not affect copulation duration, the likelihood of mating, female anti-predator behavior during or after mating or male anti-predator behavior at any time. CONCLUSIONS: Inking is a common anti-predator defense in cephalopods, thought to act like a smokescreen, decoy or distraction. Female dumpling squid are probably using this form of defense in response to the increase in predation risk prior to mating. Conversely, males were undeterred by the increase in predation risk. A lack of change in these variables may occur if the benefit of completing mating outweighs the risk of predation. Prioritizing current reproduction, even under predation risk, can occur when the chance of future reproduction is low, there is substantial energetic investment into mating, or the potential fitness payoffs of mating are high.

  14. Interactions among predators and the cascading effects of vertebrate insectivores on arthropod communities and plants.

    Science.gov (United States)

    Mooney, Kailen A; Gruner, Daniel S; Barber, Nicholas A; Van Bael, Sunshine A; Philpott, Stacy M; Greenberg, Russell

    2010-04-20

    Theory on trophic interactions predicts that predators increase plant biomass by feeding on herbivores, an indirect interaction called a trophic cascade. Theory also predicts that predators feeding on predators, or intraguild predation, will weaken trophic cascades. Although past syntheses have confirmed cascading effects of terrestrial arthropod predators, we lack a comprehensive analysis for vertebrate insectivores-which by virtue of their body size and feeding habits are often top predators in these systems-and of how intraguild predation mediates trophic cascade strength. We report here on a meta-analysis of 113 experiments documenting the effects of insectivorous birds, bats, or lizards on predaceous arthropods, herbivorous arthropods, and plants. Although vertebrate insectivores fed as intraguild predators, strongly reducing predaceous arthropods (38%), they nevertheless suppressed herbivores (39%), indirectly reduced plant damage (40%), and increased plant biomass (14%). Furthermore, effects of vertebrate insectivores on predatory and herbivorous arthropods were positively correlated. Effects were strongest on arthropods and plants in communities with abundant predaceous arthropods and strong intraguild predation, but weak in communities depauperate in arthropod predators and intraguild predation. The naturally occurring ratio of arthropod predators relative to herbivores varied tremendously among the studied communities, and the skew to predators increased with site primary productivity and in trees relative to shrubs. Although intraguild predation among arthropod predators has been shown to weaken herbivore suppression, we find this paradigm does not extend to vertebrate insectivores in these communities. Instead, vertebrate intraguild preda-tion is associated with strengthened trophic cascades, and insectivores function as dominant predators in terrestrial plant-arthropod communities. PMID:20368418

  15. Perceptual advertisement by the prey of stalking or ambushing predators.

    Science.gov (United States)

    Broom, Mark; Ruxton, Graeme D

    2012-12-21

    There has been previous theoretical explorations of the stability of signals by prey that they have detected a stalking or ambush predator, where such perceptual advertisement dissuades the predator from attacking. Here we use a game theoretical model to extend the theory to consider some empirically-motivated complexities: (i) many perceptual advertisement signals appear to have the potential to vary in intensity, (ii) higher intensity signals are likely to be most costly to produce, and (iii) some high-cost signals (such as staring directly at the predator) can only be utilised if the prey is very confident of the existence of a nearby predator (that is, there are reserved or unfakable signals). We demonstrate that these complexities still allow for stable signalling. However, we do not find solutions where prey use a range of signal intensities to signal different degrees of confidence in the proximity of a predator; with prey simply adopting a binary response of not signalling or always signalling at the same fixed level. However this fixed level will not always be the cheapest possible signal, and we predict that prey that require more certainty about proximity of a predator will use higher-cost signals. The availability of reserved signals does not prohibit the stability of signalling based on lower-cost signals, but we also find circumstances where only the reserved signal is used. We discuss the potential to empirically test our model predictions, and to develop theory further to allow perceptual advertisement to be combined with other signalling functions. PMID:22960570

  16. Successful treatment of chronic lower respiratory tract infection by macrolide administration in a patient with intralobar pulmonary sequestration and primary ciliary dyskinesia.

    Science.gov (United States)

    Tsubouchi, Hironobu; Matsumoto, Nobuhiro; Yanagi, Shigehisa; Ashitani, Jun-Ichi; Nakazato, Masamitsu

    2015-01-01

    Primary ciliary dyskinesia (PCD) is a genetic disease associated with abnormalities in ciliary structure and function. Although recurrent respiratory infection associated with ciliary dysfunction is a common clinical feature, there is no standardized treatment or management of respiratory infection in PCD patients. Here, we report that respiratory infection with PCD and intralobar sequestration (ILS) were treated successfully with clarithromycin before the surgical resection of ILS. A 15-year-old non-smoking Japanese woman was admitted for productive cough and dyspnea on exertion. Chest CT scan on admission showed complex cystic LESIONS with air-fluid level in the right lower lobe, and diffuse nodular shadows in the whole lobe of the lung. On flexible bronchoscopy examination, sputum and bronchiolar fluid cultures revealed Staphylococcus aureus (S. aureus). An electron microscopic examination of the cilia showed inner dynein arm deficiency. Administration of clarithromycin improved the lower respiratory tract infection associated with S. aureus. CT angiography after clarithromycin treatment demonstrated an aberrant systemic artery arising from the celiac trunk and supplying the cystic mass lesions that were incorporated into the normal pulmonary parenchyma without their own pleural covering. Based on these results, the patient was diagnosed with PCD and ILS. Because of the clarithromycin treatment, resection of the ILS was performed safely without any complications. Although further observation of clarithromycin treatment is needed, we believe that clarithromycin may be considered one of the agents for treating PCD. PMID:26236606

  17. A G-protein activation cascade from Arl13B to Arl3 and implications for ciliary targeting of lipidated proteins.

    Science.gov (United States)

    Gotthardt, Katja; Lokaj, Mandy; Koerner, Carolin; Falk, Nathalie; Gießl, Andreas; Wittinghofer, Alfred

    2015-01-01

    Small G-proteins of the ADP-ribosylation-factor-like (Arl) subfamily have been shown to be crucial to ciliogenesis and cilia maintenance. Active Arl3 is involved in targeting and releasing lipidated cargo proteins from their carriers PDE6δ and UNC119a/b to the cilium. However, the guanine nucleotide exchange factor (GEF) which activates Arl3 is unknown. Here we show that the ciliary G-protein Arl13B mutated in Joubert syndrome is the GEF for Arl3, and its function is conserved in evolution. The GEF activity of Arl13B is mediated by the G-domain plus an additional C-terminal helix. The switch regions of Arl13B are involved in the interaction with Arl3. Overexpression of Arl13B in mammalian cell lines leads to an increased Arl3·GTP level, whereas Arl13B Joubert-Syndrome patient mutations impair GEF activity and thus Arl3 activation. We anticipate that through Arl13B's exclusive ciliary localization, Arl3 activation is spatially restricted and thereby an Arl3·GTP compartment generated where ciliary cargo is specifically released. PMID:26551564

  18. Impact of predation by Ostracion immaculatus (Pisces: Ostraciidae) on the macrofouling community structure in Kanayama Bay, Kii Peninsula (Japan)

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Harada, E.

    using predator inclusion as well as exclusion treatment confirmed that predation by this fish had significant impact on the structure of fouling community. The importance of predation was manifested mainly through the influence of fish on ascidians...

  19. Stochastic Lattice Gas Model for a Predator-Prey System

    CERN Document Server

    Satulovsky, J E; Satulovsky, Javier; Tome, Tania

    1994-01-01

    We propose a stochastic lattice gas model to describe the dynamics of two animal species population, one being a predator and the other a prey. This model comprehends the mechanisms of the Lotka-Volterra model. Our analysis was performed by using a dynamical mean-field approximation and computer simulations. Our results show that the system exhibits an oscillatory behavior of the population densities of prey and predators. For the sets of parameters used in our computer simulations, these oscillations occur at a local level. Mean-field results predict synchronized collective oscillations.

  20. Spatio-temporal dynamics of bumblebees foraging under predation risk

    CERN Document Server

    Lenz, Friedrich; Chittka, Lars; Chechkin, Aleksei V; Klages, Rainer

    2011-01-01

    We study bumblebees searching for nectar in a laboratory experiment with and without different types of artificial spiders as predators. We find that the flight velocities obey mixed probability distributions reflecting the access to the food sources while the threat posed by the spiders shows up only in the velocity correlations. This means that the bumblebees adjust their flight patterns spatially to the environment and temporally to the predation risk. Key information on response to environmental changes is thus contained in temporal correlation functions and not in spatial distributions.

  1. The Truth About the Internet and Online Predators

    CERN Document Server

    Dingwell, Heath; Peterson, Fred L

    2011-01-01

    To help readers avoid and recognize risky behaviors, The Truth About the Internet and Online Predators explains many of the dangers associated with the Internet. The A-to-Z entries detail the social, legal, and personal risks of Internet use, while personal testimonies and question-and-answer sections provide readers with an inside look at common issues online. Entries include:. Bullies and cyberbullying. Characteristics of online predators. Chat rooms and instant messaging. Internet safety. Parental control. Peers and peer pressure. Phishing and pharming. Privacy issues. Social networking Web

  2. Responses of tadpoles to hybrid predator odours: strong maternal signatures and the potential risk/response mismatch

    OpenAIRE

    Chivers, Douglas P.; Mathiron, Anthony; Sloychuk, Janelle R.; Ferrari, Maud C. O.

    2015-01-01

    Previous studies have established that when a prey animal knows the identity of a particular predator, it can use this knowledge to make an ‘educated guess' about similar novel predators. Such generalization of predator recognition may be particularly beneficial when prey are exposed to introduced and invasive species of predators or hybrids. Here, we examined generalization of predator recognition for woodfrog tadpoles exposed to novel trout predators. Tadpoles conditioned to recognize tiger...

  3. Evidence of weaker phenotypic plasticity by prey to novel cues from non-native predators.

    Science.gov (United States)

    Hollander, Johan; Bourdeau, Paul E

    2016-08-01

    A central question in evolutionary biology is how coevolutionary history between predator and prey influences their interactions. Contemporary global change and range expansion of exotic organisms impose a great challenge for prey species, which are increasingly exposed to invading non-native predators, with which they share no evolutionary history. Here, we complete a comprehensive survey of empirical studies of coevolved and naive predator-prey interactions to assess whether a shared evolutionary history with predators influences the magnitude of predator-induced defenses mounted by prey. Using marine bivalves and gastropods as model prey, we found that coevolved prey and predator-naive prey showed large discrepancies in magnitude of predator-induced phenotypic plasticity. Although naive prey, predominantly among bivalve species, did exhibit some level of plasticity - prey exposed to native predators showed significantly larger amounts of phenotypic plasticity. We discuss these results and the implications they may have for native communities and ecosystems. PMID:27551388

  4. Demographic parameters of the insecticide-exposed predator Podisus nigrispinus: implications for IPM

    Science.gov (United States)

    The predator Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) shows potential for Integrated Pest Management programs of defoliating caterpillars in agricultural and forestry systems. Insecticides can indirectly affect caterpillar predators through consumption of contaminated prey. We examin...

  5. Experimental warming transforms multiple predator effects in a grassland food web.

    Science.gov (United States)

    Barton, Brandon T; Schmitz, Oswald J

    2009-12-01

    This experimental study tests new theory for multiple predator effects on communities by using warming to alter predator habitat use and hence direct and indirect interactions in a grassland food web containing two dominant spider predator species, a dominant grasshopper herbivore and grass and herb plants. Experimental warming further offers insight into how climate change might alter direct and indirect effects. Under ambient environmental conditions, spiders used habitat in spatially complementary locations. Consistent with predictions, the multiple predator effect on grasshoppers and on plants was the average of the individual predator effects. Warming strengthened the single predator effects. It also caused the spider species to overlap lower in the vegetation canopy. Consistent with predictions, the system was transformed into an intraguild predation system with the consequent extinction of one spider species. The results portend climate caused loss of predator diversity with important consequences for food web structure and function. PMID:19780788

  6. Factors influencing the predation rates of Anisops breddini (Hemiptera: Notonectidae feeding on mosquito larvae

    Directory of Open Access Journals (Sweden)

    R. Weterings

    2014-12-01

    Full Text Available Notonectidae are a family of water bugs that are known to be important predators of mosquito larvae and have great potential in the biological control of vector mosquitoes. An experiment was conducted to assess mosquito larvae predation by Anisops breddini, a species common to Southeast Asia. The predation rates were recorded in context of prey density, predator density, predator size and prey type. Predation rates were strongly affected by prey type and less by prey density and predator density. They ranged between 1.2 prey items per day for pupae of Aedes aegeypti and Armigeres moultoni to 5.9 for Ae. aegypti larvae. Compared with studies on other Notonectidae species, the predation rates appear low, which is probably caused by the relative small size of the specimens used in this study. An. breddini is very common in the region and often found in urban areas; therefore, the species has potential as a biological control agent.

  7. Natural and human-induced predation on Cape Cormorants at Dyer Island

    NARCIS (Netherlands)

    Voorbergen, A.; Boer, de W.F.; Underhill, L.G.

    2012-01-01

    To develop conservation strategies for vulnerable seabird species that need attention, it is important to know which factors influence their breeding productivity. Predation of eggs and chicks can have large influences on seabird reproduction, especially when human disturbance facilitates predation.

  8. Intense predation cannot always be detected experimentally: A case study of shorebird predation on nereid polychaetes in South Africa

    Science.gov (United States)

    Kalejta, B.

    The effect of predation by curlew sandpipers Calidris ferruginea L. and grey plovers Pluvialis squatarola (L.) on populations of nereid worms Ceratonereis keiskama (Day) and C. erythraeensis (Fauvel) was studied at the Berg River estuary, South Africa, by comparing observations of shorebird-foraging intensity with the results of a population study of two species of nereid worms within and outside bird exclosures. The study was carried out during the four-month period prior to northward migration of shorebirds. Population structure of the two nereid species differed considerably. Ceratonereis keiskama reproduced earlier than C. erythraeensis and only young individuals were present during the study. By contrast, old C. erythraeensis were available to the birds at the start of the experiment and young animals entered the population during the experiment. Despite selective predation on certain size classes of nereids by the birds, no significant changes in the population structure of either nereid were detected by the cage experiment. Numbers and biomass of both Ceratonereis spp. in paired controls and cages tracked each other and did not diverge as predicted. A consistent difference in the depth stratification of the two nereids may, however, have been due to predation pressure. Curlew sandpipers were calculated to remove 3112 nereids per m 2 during the three months, equivalent to 4.4. g (dry weight) per m 2. This represents 58% of the initial numbers and 77% of the initial biomass of nereids. Although predation on nereids by waders was exceptionally high at the Berg River estuary, any depletion in numbers or biomass of nereids caused by these predators was masked by the reproduction of the nereids. The fact that the predators' high energy requirements prior to northward migration coincide with the period of peak production of invertebrate prey makes the Berg River estuary an exceptionally favourable wintering area.

  9. Plastic hatching timing by red-eyed treefrog embryos interacts with larval predator identity and sublethal predation to affect prey morphology but not performance.

    Science.gov (United States)

    Touchon, Justin C; Wojdak, Jeremy M

    2014-01-01

    Many animals respond to predation risk by altering their morphology, behavior, or life-history. We know a great deal about the cues prey respond to and the changes to prey that can be induced by predation risk, but less is known about how plastic responses to predators may be affected by separate plastic responses occurring earlier in life, particularly during the embryonic period. Embryos of a broad array of taxa can respond to egg- or larval-stage risks by altering hatching timing, which may alter the way organisms respond to future predators. Using the red-eyed treefrog (Agalychnis callidryas), a model for understanding the effects of plasticity across life-stages, we assessed how the combined effects of induced variation in the timing of embryo hatching and variation in the larval predator community impacted tadpole morphology, pigmentation and swimming performance. We found that A. callidryas tadpoles developed deeper tail muscles and fins and darker pigmentation in response to fish predators, either when alone or in diverse community with other predators. Tadpoles altered morphology much less so to dragonfly naiads or water bugs. Interestingly, morphological responses to predators were also affected by induced differences in hatching age, with early and late-hatched tadpoles exhibiting different allometric relationships between tail height and body length in different predator environments. Beyond induced morphological changes, fish predators often damaged tadpoles' tails without killing them (i.e., sublethal predation), but these tadpoles swam equally quickly to those with fully intact tails. This was due to the fact that tadpoles with more damaged tails increased tail beats to achieve equal swimming speed. This study demonstrates that plastic phenotypic responses to predation risk can be influenced by a complex combination of responses to both the embryo and larval environments, but also that prey performance can be highly resilient to sublethal predation

  10. Plastic hatching timing by red-eyed treefrog embryos interacts with larval predator identity and sublethal predation to affect prey morphology but not performance.

    Directory of Open Access Journals (Sweden)

    Justin C Touchon

    Full Text Available Many animals respond to predation risk by altering their morphology, behavior, or life-history. We know a great deal about the cues prey respond to and the changes to prey that can be induced by predation risk, but less is known about how plastic responses to predators may be affected by separate plastic responses occurring earlier in life, particularly during the embryonic period. Embryos of a broad array of taxa can respond to egg- or larval-stage risks by altering hatching timing, which may alter the way organisms respond to future predators. Using the red-eyed treefrog (Agalychnis callidryas, a model for understanding the effects of plasticity across life-stages, we assessed how the combined effects of induced variation in the timing of embryo hatching and variation in the larval predator community impacted tadpole morphology, pigmentation and swimming performance. We found that A. callidryas tadpoles developed deeper tail muscles and fins and darker pigmentation in response to fish predators, either when alone or in diverse community with other predators. Tadpoles altered morphology much less so to dragonfly naiads or water bugs. Interestingly, morphological responses to predators were also affected by induced differences in hatching age, with early and late-hatched tadpoles exhibiting different allometric relationships between tail height and body length in different predator environments. Beyond induced morphological changes, fish predators often damaged tadpoles' tails without killing them (i.e., sublethal predation, but these tadpoles swam equally quickly to those with fully intact tails. This was due to the fact that tadpoles with more damaged tails increased tail beats to achieve equal swimming speed. This study demonstrates that plastic phenotypic responses to predation risk can be influenced by a complex combination of responses to both the embryo and larval environments, but also that prey performance can be highly resilient to

  11. Generalization of predator recognition: Velvet geckos display anti-predator behaviours in response to chemicals from non-dangerous elapid snakes

    Directory of Open Access Journals (Sweden)

    Jonathan K. WEBB, Weiguo DU, David PIKE, Richard SHINE

    2010-06-01

    Full Text Available Many prey species detect chemical cues from predators and modify their behaviours in ways that reduce their risk of predation. Theory predicts that prey should modify their anti-predator responses according to the degree of threat posed by the predator. That is, prey should show the strongest responses to chemicals of highly dangerous prey, but should ignore or respond weakly to chemicals from non-dangerous predators. However, if anti-predator behaviours are not costly, and predators are rarely encountered, prey may exhibit generalised antipredator behaviours to dangerous and non-dangerous predators. In Australia, most elapid snakes eat lizards, and are therefore potentially dangerous to lizard prey. Recently, we found that the nocturnal velvet gecko Oedura lesueurii responds to chemicals from dangerous and non-dangerous elapid snakes, suggesting that it displays generalised anti-predator behaviours to chemicals from elapid snakes. To explore the generality of this result, we videotaped the behaviour of velvet geckos in the presence of chemical cues from two small elapid snakes that rarely consume geckos: the nocturnal golden-crowned snake Cacophis squamulosus and the diurnal marsh snake Hemiaspis signata. We also videotaped geckos in trials involving unscented cards (controls and cologne-scented cards (pungency controls. In trials involving Cacophis and Hemiaspis chemicals, 50% and 63% of geckos spent long time periods (> 3 min freezing whilst pressed flat against the substrate, respectively. Over half the geckos tested exhibited anti-predator behaviours (tail waving, tail vibration, running in response to Cacophis (67% or Hemiaspis (63% chemicals. These behaviours were not observed in control or pungency control trials. Our results support the idea that the velvet gecko displays generalised anti-predator responses to chemical cues from elapid snakes. Generalised responses to predator chemicals may be common in prey species that co-occur with

  12. Effects of an Infectious Fungus, Batrachochytrium dendrobatidis, on Amphibian Predator-Prey Interactions

    OpenAIRE

    Han, Barbara A; Catherine L Searle; BLAUSTEIN, ANDREW R.

    2011-01-01

    The effects of parasites and pathogens on host behaviors may be particularly important in predator-prey contexts, since few animal behaviors are more crucial for ensuring immediate survival than the avoidance of lethal predators in nature. We examined the effects of an emerging fungal pathogen of amphibians, Batrachochytrium dendrobatidis, on anti-predator behaviors of tadpoles of four frog species. We also investigated whether amphibian predators consumed infected prey, and whether B. dendro...

  13. Skin toxins in coral-associated Gobiodon species (Teleostei: Gobiidae) affect predator preference and prey survival

    OpenAIRE

    Gratzer, Barbara; Millesi, Eva; Walzl, Manfred; Herler, Juergen

    2014-01-01

    Predation risk is high for the many small coral reef fishes, requiring successful sheltering or other predator defence mechanisms. Coral-dwelling gobies of the genus Gobiodon live in close association with scleractinian corals of the genus Acropora. Earlier studies indicated that the low movement frequency of adult fishes and the development of skin toxins (crinotoxicity) are predation avoidance mechanisms. Although past experiments showed that predators refuse food prepared with goby skin mu...

  14. Competition between foraging predators and hiding preys as a nonzero-sum differential game

    OpenAIRE

    Akhmetzhanov, Andrei,; Bernhard, Pierre; Grognard, Frédéric; Mailleret, Ludovic

    2009-01-01

    International audience — In this work we investigate a (seasonal) prey-predator model where the system evolves during a season whose length is fixed. Predators have the choice between foraging the food (eating preys) and reproducing (laying eggs at a rate proportional to their energy). Preys can either eat, which would maintain their population in the absence of predators, or hide from the predators but they then suffer a positive mortality rate. In this case the population size can decrea...

  15. Effect of Locally Administered Ciliary Neurotrophic Factor on the Survival of Transected and Repaired Adult Sheep Facial Nerve

    Directory of Open Access Journals (Sweden)

    Rashid Al Abri

    2014-05-01

    Full Text Available Objective: to determine whether the administration of Ciliary Neurotrophic Factor (CNTF at the site of repaired facial nerve enhances regeneration in the adult sheep model. Methods: Ten adult sheep were divided into 2 groups: control and study group (CNTF group. In the CNTF group, the buccal branch of the facial nerve was transected and then repaired by epineural sutures. CNTF was injected over the left depressor labii maxillaris muscle in the vicinity of the transected and repaired nerve for 28 days under local anesthesia. In the CNTF group, the sheep were again anesthetized after nine months and the site of facial nerve repair was exposed. Detailed electrophysiological, tension experiments and morphometric studies were carried out and then analyzed statistically. Results: The skin CV min, refractory period, Jitter and tension parameters were marginally raised in the CNTF group than the control but the difference was statistically insignificant between the two groups. Morphometric indices also did not show any significant changes in the CNTF group. Conclusion: CNTF has no profound effect on neuronal regeneration of adult sheep animal model.

  16. Collagen scaffolds combined with collagen-binding ciliary neurotrophic factor facilitate facial nerve repair in mini-pigs.

    Science.gov (United States)

    Lu, Chao; Meng, Danqing; Cao, Jiani; Xiao, Zhifeng; Cui, Yi; Fan, Jingya; Cui, Xiaolong; Chen, Bing; Yao, Yao; Zhang, Zhen; Ma, Jinling; Pan, Juli; Dai, Jianwu

    2015-05-01

    The preclinical studies using animal models play a very important role in the evaluation of facial nerve regeneration. Good models need to recapitulate the distance and time for axons to regenerate in humans. Compared with the most used rodent animals, the structure of facial nerve in mini-pigs shares more similarities with humans in microanatomy. To evaluate the feasibility of repairing facial nerve defects by collagen scaffolds combined with ciliary neurotrophic factor (CNTF), 10-mm-long gaps were made in the buccal branch of mini-pigs' facial nerve. Three months after surgery, electrophysiological assessment and histological examination were performed to evaluate facial nerve regeneration. Immunohistochemistry and transmission electron microscope observation showed that collagen scaffolds with collagen binding (CBD)-CNTF could promote better axon regeneration, Schwann cell migration, and remyelination at the site of implant device than using scaffolds alone. Electrophysiological assessment also showed higher recovery rate in the CNTF group. In summary, combination of collagen scaffolds and CBD-CNTF showed promising effects on facial nerve regeneration in mini-pig models. PMID:25098760

  17. Ciliary neurotrophic factor (CNTF): New facets of an old molecule for treating neurodegenerative and metabolic syndrome pathologies.

    Science.gov (United States)

    Pasquin, Sarah; Sharma, Mukut; Gauchat, Jean-François

    2015-10-01

    Ciliary neurotrophic factor (CNTF) is the most extensively studied member of the cytokine family that signal through intracellular chains of the gp130/LIFRβ receptor. The severe phenotype in patients suffering from mutations inactivating LIFRβ indicates that members of this cytokine family play key, non-redundant roles during development. Accordingly, three decades of research has revealed potent and promising trophic and regulatory activities of CNTF in neurons, oligodendrocytes, muscle cells, bone cells, adipocytes and retinal cells. These findings led to clinical trials to test the therapeutic potential of CNTF and CNTF derivatives for treating neurodegenerative and metabolic diseases. Promising results have encouraged continuation of studies for treating retinal degenerative diseases. Results of some clinical trials showed that side-effects may limit the systemically administrated doses of CNTF. Therefore, therapies being currently tested rely on local delivery of CNTF using encapsulated cytokine-secreting implants. Since the side effects of CNTF might be linked to its ability to activate the alternative IL6Rα-LIFRβ-gp130 receptor, CNTFR-specific mutants of CNTF have been developed that bind to the CNTFRα-LIFRβ-gp130 receptor. These developments may prove to be a breakthrough for therapeutic applications of systemically administered CNTF in pathologies such as multiple sclerosis or Alzheimer's disease. The "designer cytokine approach" offers future opportunities to further enhance specificity by conjugating mutant CNTF with modified soluble CNTFRα to target therapeutically relevant cells that express gp130-LIFRβ and a specific cell surface marker. PMID:26187860

  18. The cytokine ciliary neurotrophic factor (CNTF activates hypothalamic urocortin-expressing neurons both in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Matthew J Purser

    Full Text Available Ciliary neurotrophic factor (CNTF induces neurogenesis, reduces feeding, and induces weight loss. However, the central mechanisms by which CNTF acts are vague. We employed the mHypoE-20/2 line that endogenously expresses the CNTF receptor to examine the direct effects of CNTF on mRNA levels of urocortin-1, urocortin-2, agouti-related peptide, brain-derived neurotrophic factor, and neurotensin. We found that treatment of 10 ng/ml CNTF significantly increased only urocortin-1 mRNA by 1.84-fold at 48 h. We then performed intracerebroventricular injections of 0.5 mg/mL CNTF into mice, and examined its effects on urocortin-1 neurons post-exposure. Through double-label immunohistochemistry using specific antibodies against c-Fos and urocortin-1, we showed that central CNTF administration significantly activated urocortin-1 neurons in specific areas of the hypothalamus. Taken together, our studies point to a potential role for CNTF in regulating hypothalamic urocortin-1-expressing neurons to mediate its recognized effects on energy homeostasis, neuronal proliferaton/survival, and/or neurogenesis.

  19. Protein Profiling of Human Nonpigmented Ciliary Epithelium Cell Secretome: The Differentiation Factors Characterization for Retinal Ganglion Cell line

    Directory of Open Access Journals (Sweden)

    Ming-Hui Yang

    2011-01-01

    Full Text Available The purpose of this paper was to characterize proteins secreted from the human nonpigmented ciliary epithelial (HNPE cells, which have differentiated a rat retinal ganglion cell line, RGC-5. Undifferentiated RGC-5 cells have been shown to express several marker proteins characteristic of retinal ganglion cells. However, RGC-5 cells do not respond to N-methyl-D aspartate (NMDA, or glutamate. HNPE cells have been shown to secrete numbers of neuropeptides or neuroproteins also found in the aqueous humor, many of which have the ability to influence the activity of neuronal cells. This paper details the profile of HNPE cell-secreted proteins by proteomic approaches. The experimental results revealed the identification of 132 unique proteins from the HNPE cell-conditioned SF-medium. The biological functions of a portion of these identified proteins are involved in cell differentiation. We hypothesized that a differentiation system of HNPE cell-conditioned SF-medium with RGC-5 cells can induce a differentiated phenotype in RGC-5 cells, with functional characteristics that more closely resemble primary cultures of rat retinal ganglion cells. These proteins may replace harsh chemicals, which are currently used to induce cell differentiation.

  20. What cues do ungulates use to assess predation risk in dense temperate forests?

    NARCIS (Netherlands)

    Kuijper, Dries P.J.; Verwijmeren, Mart; Churski, Marcin; Zbyryt, Adam; Schmidt, Krzysztof; Jędrzejewska, Bogumiła; Smit, Chris

    2014-01-01

    Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in t

  1. A functional response model of a predator population foraging in a patchy habitat

    DEFF Research Database (Denmark)

    Nachman, Gösta

    2006-01-01

    1. Functional response models (e.g. Holling's disc equation) that do not take the spatial distributions of prey and predators into account are likely to produce biased estimates of predation rates. 2. To investigate the consequences of ignoring prey distribution and predator aggregation, a genera...

  2. Prey refuges as predator hotspots: ocelot (Leopardus pardalis) attraction to agouti (Dasyprocta punctata) dens

    NARCIS (Netherlands)

    Emsens, W.J.; Hirsch, B.T.; Kays, R.; Jansen, P.A.

    2014-01-01

    We tested the hypothesis that prey refuges attract predators, leading to elevated predator activity in the vicinity of refuges. We used camera traps to determine whether the spatial activity of a predator, the ocelot (Leopardus pardalis), was biased toward refuge locations of its principal prey, the

  3. Controllability and Optimal Harvesting of a Prey-Predator Model Incorporating a Prey Refuge

    Science.gov (United States)

    Kar, Tapan Kumar

    2006-01-01

    This paper deals with a prey-predator model incorporating a prey refuge and harvesting of the predator species. A mathematical analysis shows that prey refuge plays a crucial role for the survival of the species and that the harvesting effort on the predator may be used as a control to prevent the cyclic behaviour of the system. The optimal…

  4. Density-dependent interactions in an Arctic char - brown trout system: competition, predation, or both?

    NARCIS (Netherlands)

    L. Persson; P.A. Amundsen; A.M. de Roos; R. Knudsen; R. Primicerio; A. Klemetsen

    2013-01-01

    In the study of mechanisms structuring fish communities, mixed competition-predation interactions where large predators feed on prey fish versus those in which small predators compete with prey fish for a shared prey have been the focus of substantial research. We used a long-term data set from a sy

  5. Nonselective Harvesting of a Prey-Predator Fishery with Gompertz Law of Growth

    Science.gov (United States)

    Purohit, D.; Chaudhuri, K. S.

    2002-01-01

    This paper develops a mathematical model for the nonselective harvesting of a prey-predator system in which both the prey and the predator obey the Gompertz law of growth and some prey avoid predation by hiding. The steady states of the system are determined, and the dynamical behaviour of both species is examined. The possibility of existence of…

  6. Anti-predator behaviour of Sahamalaza sportive lemurs, Lepilemur sahamalazensis, at diurnal sleeping sites

    NARCIS (Netherlands)

    Seiler, M.; Schwitzer, C.; Holderied, M.

    2013-01-01

    In response to predation pressure by raptors, snakes, and carnivores, primates employ anti-predator behaviours such as avoiding areas of high predation risk, cryptic behaviour and camouflage, vigilance and group formation (including mixedspecies associations), and eavesdropping on other species’ ala

  7. Small nonnative fishes as predators of larval razorback suckers

    Science.gov (United States)

    Carpenter, J.; Mueller, G.A.

    2008-01-01

    The razorback sucker (Xyrauchen texanus), an endangered big-river fish of the Colorado River basin, has demonstrated no sustainable recruitment in 4 decades, despite presence of spawning adults and larvae. Lack of adequate recruitment has been attributed to several factors, including predation by nonnative fishes. Substantial funding and effort has been expended on mechanically removing nonnative game fishes, typically targeting large predators. As a result, abundance of larger predators has declined, but the abundance of small nonnative fishes has increased in some areas. We conducted laboratory experiments to determine if small nonnative fishes would consume larval razorback suckers. We tested adults of three small species (threadfin shad, Dorosoma petenense; red shiner, Cyprinella lutrensis; fathead minnow, Pimephales promelas) and juveniles of six larger species (common carp, Cyprinus carpio; yellow bullhead, Ameiurus natalis; channel catfish, Ictalurus punctatus; rainbow trout, Oncorhynchus mykiss; green sunfish, Lepomis cyanellus; bluegill, L. macrochirus). These nonnative fishes span a broad ecological range and are abundant within the historical range of the razorback sucker. All nine species fed on larval razorback suckers (total length, 9-16 mm). Our results suggest that predation by small nonnative fishes could be responsible for limiting recovery of this endangered species.

  8. Sizing up your enemy: individual predation vulnerability predicts migratory probability.

    Science.gov (United States)

    Skov, Christian; Baktoft, Henrik; Brodersen, Jakob; Brönmark, Christer; Chapman, Ben B; Hansson, Lars-Anders; Nilsson, P Anders

    2011-05-01

    Partial migration, in which a fraction of a population migrate and the rest remain resident, occurs in an extensive range of species and can have powerful ecological consequences. The question of what drives differences in individual migratory tendency is a contentious one. It has been shown that the timing of partial migration is based upon a trade-off between seasonal fluctuations in predation risk and growth potential. Phenotypic variation in either individual predation risk or growth potential should thus mediate the strength of the trade-off and ultimately predict patterns of partial migration at the individual level (i.e. which individuals migrate and which remain resident). We provide cross-population empirical support for the importance of one component of this model--individual predation risk--in predicting partial migration in wild populations of bream Abramis brama, a freshwater fish. Smaller, high-risk individuals migrate with a higher probability than larger, low-risk individuals, and we suggest that predation risk maintains size-dependent partial migration in this system. PMID:20980300

  9. Stochastic population oscillations in spatial predator-prey models

    Energy Technology Data Exchange (ETDEWEB)

    Taeuber, Uwe C, E-mail: tauber@vt.edu [Department of Physics, Virginia Tech, Blacksburg, VA 24061-0435 (United States)

    2011-09-15

    It is well-established that including spatial structure and stochastic noise in models for predator-prey interactions invalidates the classical deterministic Lotka-Volterra picture of neutral population cycles. In contrast, stochastic models yield long-lived, but ultimately decaying erratic population oscillations, which can be understood through a resonant amplification mechanism for density fluctuations. In Monte Carlo simulations of spatial stochastic predator-prey systems, one observes striking complex spatio-temporal structures. These spreading activity fronts induce persistent correlations between predators and prey. In the presence of local particle density restrictions (finite prey carrying capacity), there exists an extinction threshold for the predator population. The accompanying continuous non-equilibrium phase transition is governed by the directed-percolation universality class. We employ field-theoretic methods based on the Doi-Peliti representation of the master equation for stochastic particle interaction models to (i) map the ensuing action in the vicinity of the absorbing state phase transition to Reggeon field theory, and (ii) to quantitatively address fluctuation-induced renormalizations of the population oscillation frequency, damping, and diffusion coefficients in the species coexistence phase.

  10. Direct identification of predator-prey dynamics in gyrokinetic simulations

    Science.gov (United States)

    Kobayashi, Sumire; Gürcan, Özgür D.; Diamond, Patrick H.

    2015-09-01

    The interaction between spontaneously formed zonal flows and small-scale turbulence in nonlinear gyrokinetic simulations is explored in a shearless closed field line geometry. It is found that when clear limit cycle oscillations prevail, the observed turbulent dynamics can be quantitatively captured by a simple Lotka-Volterra type predator-prey model. Fitting the time traces of full gyrokinetic simulations by such a reduced model allows extraction of the model coefficients. Scanning physical plasma parameters, such as collisionality and density gradient, it was observed that the effective growth rates of turbulence (i.e., the prey) remain roughly constant, in spite of the higher and varying level of primary mode linear growth rates. The effective growth rate that was extracted corresponds roughly to the zonal-flow-modified primary mode growth rate. It was also observed that the effective damping of zonal flows (i.e., the predator) in the parameter range, where clear predator-prey dynamics is observed, (i.e., near marginal stability) agrees with the collisional damping expected in these simulations. This implies that the Kelvin-Helmholtz-like instability may be negligible in this range. The results imply that when the tertiary instability plays a role, the dynamics becomes more complex than a simple Lotka-Volterra predator prey.

  11. Direct identification of predator-prey dynamics in gyrokinetic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Sumire, E-mail: sumire.kobayashi@lpp.polytechnique.fr; Gürcan, Özgür D [Laboratoire de Physique des Plasmas, CNRS, Paris-Sud, Ecole Polytechnique, UMR7648, F-91128 Palaiseau (France); Diamond, Patrick H. [University of California, San Diego, La Jolla, California 92093-0319 (United States)

    2015-09-15

    The interaction between spontaneously formed zonal flows and small-scale turbulence in nonlinear gyrokinetic simulations is explored in a shearless closed field line geometry. It is found that when clear limit cycle oscillations prevail, the observed turbulent dynamics can be quantitatively captured by a simple Lotka-Volterra type predator-prey model. Fitting the time traces of full gyrokinetic simulations by such a reduced model allows extraction of the model coefficients. Scanning physical plasma parameters, such as collisionality and density gradient, it was observed that the effective growth rates of turbulence (i.e., the prey) remain roughly constant, in spite of the higher and varying level of primary mode linear growth rates. The effective growth rate that was extracted corresponds roughly to the zonal-flow-modified primary mode growth rate. It was also observed that the effective damping of zonal flows (i.e., the predator) in the parameter range, where clear predator-prey dynamics is observed, (i.e., near marginal stability) agrees with the collisional damping expected in these simulations. This implies that the Kelvin-Helmholtz-like instability may be negligible in this range. The results imply that when the tertiary instability plays a role, the dynamics becomes more complex than a simple Lotka-Volterra predator prey.

  12. Chaotic behaviour of a predator-prey system

    NARCIS (Netherlands)

    Kooi, B.W.; Boer, M.P.

    2003-01-01

    Generally a predator-prey system is modelled by two ordinary differential equations which describe the rate of changes of the biomasses. Since such a system is two-dimensional no chaotic behaviour can occur. In the popular Rosenzweig-MacArthur model, which replaced the Lotka-Volterra model, a stable

  13. Predator efficiency reconsidered for a ladybird-aphid system

    Czech Academy of Sciences Publication Activity Database

    Kindlmann, Pavel; Yasuda, H.; Kajita, Y.; Sato, S.; Dixon, Anthony F. G.

    2015-01-01

    Roč. 3, mar (2015), s. 27. ISSN 2296-701X R&D Projects: GA MŠk(CZ) LO1415; GA ČR GB14-36098G Institutional support: RVO:67179843 Keywords : biological control * generation time ratio * population dynamics * predator-prey systems * ladybirds * aphids Subject RIV: EH - Ecology, Behaviour

  14. Antelope Predation by Nigerian Forest Baboons: Ecological and Behavioural Correlates.

    Science.gov (United States)

    Sommer, Volker; Lowe, Adriana; Jesus, Gonçalo; Alberts, Nienke; Bouquet, Yaëlle; Inglis, David M; Petersdorf, Megan; van Riel, Eelco; Thompson, James; Ross, Caroline

    2016-01-01

    Baboons are well studied in savannah but less so in more closed habitats. We investigated predation on mammals by olive baboons (Papio anubis) at a geographical and climatic outlier, Gashaka Gumti National Park (Nigeria), the wettest and most forested site so far studied. Despite abundant wildlife, meat eating was rare and selective. Over 16 years, baboons killed 7 bushbuck (Tragelaphus scriptus) and 3 red-flanked duiker (Cephalophus rufilatus), mostly still-lying 'parked' infants. Taking observation time into account, this is 1 predation per group every 3.3 months - far lower than at other sites. Some features of meat eating resemble those elsewhere; predation is opportunistic, adult males monopolize most prey, a targeted killing bite is lacking and begging or active sharing is absent. Carcass owners employ evasive tactics, as meat is often competed over, but satiated owners may tolerate others taking meat. Other features are unusual; this is only the second study site with predation records for bushbuck and the only one for red-flanked duiker. The atypical prey and rarity of eating mammals probably reflects the difficulty of acquiring prey animals when vegetation cover is dense. Our data support the general prediction of the socioecological model that environments shape behavioural patterns, while acknowledging their intraspecific or intrageneric plasticity. PMID:27287424

  15. Parasitology: Parasite survives predation on its host

    DEFF Research Database (Denmark)

    Ponton, Fleur; Lebarbenchon, Camille; Lefèvre, Thierry;

    2006-01-01

    As prisoners in their living habitat, parasites should be vulnerable to destruction by the predators of their hosts. But we show here that the parasitic gordian worm Paragordius tricuspidatus is able to escape not only from its insect host after ingestion by a fish or frog but also from the diges...

  16. Preferential feeding on male prey stabilizes predator-prey dynamics

    Czech Academy of Sciences Publication Activity Database

    Berec, Luděk; Křivan, Vlastimil; Boukal S., David

    Dresden : Center for Information Services- High Performance Computing , 2005. s. 192-192. [European Conference on Mathematical and Theoretical Biology. 18.07.2005-22.07.2005, Dresden] Institutional research plan: CEZ:AV0Z50070508 Keywords : predator-prey Subject RIV: EH - Ecology, Behaviour

  17. Direct identification of predator-prey dynamics in gyrokinetic simulations

    International Nuclear Information System (INIS)

    The interaction between spontaneously formed zonal flows and small-scale turbulence in nonlinear gyrokinetic simulations is explored in a shearless closed field line geometry. It is found that when clear limit cycle oscillations prevail, the observed turbulent dynamics can be quantitatively captured by a simple Lotka-Volterra type predator-prey model. Fitting the time traces of full gyrokinetic simulations by such a reduced model allows extraction of the model coefficients. Scanning physical plasma parameters, such as collisionality and density gradient, it was observed that the effective growth rates of turbulence (i.e., the prey) remain roughly constant, in spite of the higher and varying level of primary mode linear growth rates. The effective growth rate that was extracted corresponds roughly to the zonal-flow-modified primary mode growth rate. It was also observed that the effective damping of zonal flows (i.e., the predator) in the parameter range, where clear predator-prey dynamics is observed, (i.e., near marginal stability) agrees with the collisional damping expected in these simulations. This implies that the Kelvin-Helmholtz-like instability may be negligible in this range. The results imply that when the tertiary instability plays a role, the dynamics becomes more complex than a simple Lotka-Volterra predator prey

  18. Testing for Camouflage Using Virtual Prey and Human "Predators"

    Science.gov (United States)

    Todd, Peter A.

    2009-01-01

    Camouflage is a prevalent feature of the natural world and as such has a ready appeal to students; however, it is a difficult subject to study using real predators and prey. This paper focuses how one fundamental type of camouflage, disruptive colouration (bold markings that break up the outline of the organism), can be tested using paper…

  19. Does predator interference cause alternative stable states in multispecies communities?

    NARCIS (Netherlands)

    Feng, J.; Dakos, V.; Nes, van E.H.

    2012-01-01

    Whereas it is well known that simple ecological mechanisms may promote stability in simple species models, their consequences for stability and resilience in multispecies communities are largely unexplored. Here, we studied the effect of predator interference on the occurrence of alternative attract

  20. Inducible defenses, competition and shared predation in planktonic food chains

    NARCIS (Netherlands)

    van der Stap, I.; Vos, M.; Tollrian, R.; Mooij, W.M.

    2008-01-01

    Ecologists have long debated the role of predation in mediating the coexistence of prey species. Theory has mainly taken a bitrophic perspective that excludes the effects of inducible defenses at different trophic levels. However, inducible defenses could either limit or enhance the effects of preda