222 research outputs found

    Seasonal migration of Cnaphalocrocis medinalis (Lepidoptera: Crambidae) over the Bohai Sea in northern China

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    The rice leaf roller, Cnaphalocrocis medinalis (Guenée), is a serious insect pest of rice with a strong migratory ability. Previous studies on the migration of C. medinalis were mostly carried out in tropical or subtropical regions, however, and what the pattern of seasonal movements this species exhibits in temperate regions (i.e. Northern China, where they cannot overwinter) remains unknown. Here we present data from an 11-year study of this species made by searchlight trapping on Beihuang Island (BH, 38°24′N; 120°55′E) in the centre of the Bohai Strait, which provides direct evidence that C. medinalis regularly migrates across this sea into northeastern agricultural region of China, and to take advantage of the abundant food resources there during the summer season. There was considerable seasonal variation in number of C. medinalis trapped on BH, and the migration period during 2003–2013 ranged from 72 to 122 days. Some females trapped in June and July showed a relatively higher proportion of mated and a degree of ovarian development suggesting that the migration of this species is not completely bound by the ‘oogenesis-flight syndrome’. These findings revealed a new route for C. medinalis movements to and from Northeastern China, which will help us develop more effective management strategies against this pest

    Coastal high-frequency radars in the Mediterranean ??? Part 2: Applications in support of science priorities and societal needs

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    International audienceThe Mediterranean Sea is a prominent climate-change hot spot, with many socioeconomically vital coastal areas being the most vulnerable targets for maritime safety, diverse met-ocean hazards and marine pollution. Providing an unprecedented spatial and temporal resolution at wide coastal areas, high-frequency radars (HFRs) have been steadily gaining recognition as an effective land-based remote sensing technology for continuous monitoring of the surface circulation, increasingly waves and occasionally winds. HFR measurements have boosted the thorough scientific knowledge of coastal processes, also fostering a broad range of applications, which has promoted their integration in coastal ocean observing systems worldwide, with more than half of the European sites located in the Mediterranean coastal areas. In this work, we present a review of existing HFR data multidisciplinary science-based applications in the Mediterranean Sea, primarily focused on meeting end-user and science-driven requirements, addressing regional challenges in three main topics: (i) maritime safety, (ii) extreme hazards and (iii) environmental transport process. Additionally, the HFR observing and monitoring regional capabilities in the Mediterranean coastal areas required to underpin the underlying science and the further development of applications are also analyzed. The outcome of this assessment has allowed us to provide a set of recommendations for future improvement prospects to maximize the contribution to extending science-based HFR products into societally relevant downstream services to support blue growth in the Mediterranean coastal areas, helping to meet the UN's Decade of Ocean Science for Sustainable Development and the EU's Green Deal goals

    Coastal high-frequency radars in the Mediterranean - Part 2: Applications in support of science priorities and societal needs

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    The Mediterranean Sea is a prominent climate-change hot spot, with many socioeconomically vital coastal areas being the most vulnerable targets for maritime safety, diverse met-ocean hazards and marine pollution. Providing an unprecedented spatial and temporal resolution at wide coastal areas, high-frequency radars (HFRs) have been steadily gaining recognition as an effective land-based remote sensing technology for continuous monitoring of the surface circulation, increasingly waves and occasionally winds. HFR measurements have boosted the thorough scientific knowledge of coastal processes, also fostering a broad range of applications, which has promoted their integration in coastal ocean observing systems worldwide, with more than half of the European sites located in the Mediterranean coastal areas. In this work, we present a review of existing HFR data multidisciplinary science-based applications in the Mediterranean Sea, primarily focused on meeting end-user and science-driven requirements, addressing regional challenges in three main topics: (i) maritime safety, (ii) extreme hazards and (iii) environmental transport process. Additionally, the HFR observing and monitoring regional capabilities in the Mediterranean coastal areas required to underpin the underlying science and the further development of applications are also analyzed. The outcome of this assessment has allowed us to provide a set of recommendations for future improvement prospects to maximize the contribution to extending science-based HFR products into societally relevant downstream services to support blue growth in the Mediterranean coastal areas, helping to meet the UN's Decade of Ocean Science for Sustainable Development and the EU's Green Deal goals

    Protection Strategy against Spruce Budworm

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    Spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks are a dominant natural disturbance in the forests of Canada and northeastern USA. Widespread, severe defoliation by this native insect results in large-scale mortality and growth reductions of spruce (Picea sp.) and balsam fir (Abies balsamea (L.) Mill.) forests, and largely determines future age–class structure and productivity. The last major spruce budworm outbreak defoliated over 58 million hectares in the 1970s–1980s, and caused 32–43 million m3/year of timber volume losses from 1978 to 1987, in Canada. Management to deal with spruce budworm outbreaks has emphasized forest protection, spraying registered insecticides to prevent defoliation and keep trees alive. Other tactics can include salvage harvesting, altering harvest schedules to remove the most susceptible stands, or reducing future susceptibility by planting or thinning. Chemical insecticides are no longer used, and protection strategies use biological insecticides Bacillus thuringiensis (B.t.) or tebufenozide, a specific insect growth regulator. Over the last five years, a $30 million research project has tested another possible management tactic, termed an ‘early intervention strategy’, aimed at area-wide management of spruce budworm populations. This includes intensive monitoring to detect ‘hot spots’ of rising budworm populations before defoliation occurs, targeted insecticide treatment to prevent spread, and detailed research into target and non-target insect effects. The objective of this Special Issue is to compile the most recent research on protection strategies against spruce budworm. A series of papers will describe results and prospects for the use of an early intervention strategy in spruce budworm and other insect management

    Neuromediators in the developing olfactory system: 3D-reconstruction towards a functional understanding

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    During ontogenesis of holometabolic insects like butterflies (Lepidoptera) life circumstances change radically. While larval life is dominated by eating and growing, adult animals need to cope with quite different properties of sensory stimuli, especially during flight. This asks for a complete rebuilding of the brain during metamorphosis to fulfill adult-specific requirements. One well-established model system to examine these develomental processes is the brain of the sphinx moth Manduca sexta. Within about three weeks of pupal development the whole brain increases about ten times in size, several larval cells die, other adult-specific neuroblasts start to proliferate while other neuronal cells are restructured to deal with adult-specific tasks. Many of the underlying ontogenetic processes of outgrowing and differentiation of neural cells seem to be conserved between insects and vertebrates. On the molecular level as well as on the level of neuropilar organization exist parallels between both, which usually are more accessible in the insect model. One example would be target selection of sensory receptor neurons, which is steered by similar contact receptors. Another example is the analogous organization of olfactory neuropils into spherical glomeruli which exhibit odor-dependent activation. The gaseous signal molecule nitric oxide (NO) and its influence on neurogenesis represents another example of a conserved concept during individual development of various systems, including antennal lobe development in Manduca. The modes of action of NO are manyfold: it may influence proteins by ADP-ribosylation or S-nitrosylation, or may stimulate further intracellular signalling cascades. Most prominent example in Manduca would be the transient cGMP synthesis by NO-dependent soluble guanylyl cyclase. This cGMP in turn exhibits its own broad spectrum of downstream activation, reaching from directly dependent ion channels (cyclic nucleotide gated channels, CNGs) to protein kinases and phosphodiesterases. Within the framework of our working hypothesis the release of neuropeptides in developing local interneurons is mediated by selective cGMP production during a defined time window. This allows for specific refinement of synaptic contacts coming from a previous unspecific developmental signal. Our existing neuropeptide data was extended by anatomical and pharmacological examinations regarding allatotropin and further characterization of the lateral cell group by MALDI-TOF mass spectrometry. The emphasis of this dissertation however was laid on further characterization of the NO/cGMP signalling pathway during antennal lobe develoment of Manduca sexta. First, the cell group in question was examined towards its ability to extend the NO signal by Cu,Zn superoxide dismutase expression, followed by a test for cell death during antennal lobe development. Since no dying cells were found throughout antennal lobe development, a stable cell population could be assumed. Now, the NO/cGMP signalling pathway was further examined with respect to temporal occurrence, specificity, and number of cells involved; additionally, its possible mode of action on neuronal development was pointed out by integrating previous work. Within this framework, 3D-reconstruction based volumetry was used, which proved to be a powerful tool to answer other questions during antennal lobe development as well. Prerequisite herefore was, however, the establishment of a suitable protocol, together with the definition of easily and reproducably identifyable neuropilar regions in the antennal lobe during development. After introduction of this protocol, an extention onto whole brain neuropils was obvious, which was done in a supervised diploma work. In this context, a Manduca standard brain was created and used to volumetrically examine brain sex dimorphism. In a cooperation project, anatomical expertise on the antennal lobe system was applied by identification and classification of intracellulary recorded projection neurons, combined wtih a 4D representation of the data obtained

    New Frontiers in the Application of Stable Isotopes to Ecological and Ecophysiological Research

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    This Research Topic aims to present cutting-edge applications of stable isotope methods to animal and plant ecology and ecophysiology.https://digitalcommons.odu.edu/biology_books/1020/thumbnail.jp

    FGF signaling and cell state transitions during organogenesis

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    Organogenesis is a complex choreography of morphogenetic processes, patterns and dynamic shape changes as well as the specification of cell fates. Although several molecular actors and context-specific mechanisms have already been identified, our general understanding of the fundamental principles that govern the formation of organs is far from comprehensive. The application of the concept of ‘rebuild it to understand it’ from synthetic biology represents a promising alternative to the classical approach of ‘break it to understand it’ in order to distill biological understanding from complex developmental processes. According to this ‘rebuilding’ concept, in this study we sought to develop an experimental approach to induce the formation of organs from progenitor cells ‘on demand’ and to investigate the minimum requirements for such a process. The zebrafish lateral line chain cells are a powerful in vivo model for our study because they are a group of naïve multipotent progenitor cells that display mesenchyme-like features. In order to bring these cells to form organs, we used the well-known role of the FGF signaling pathway as a driver of organogenesis in the lateral line and developed an inducible and constitutively active form of the fibroblast growth factor receptor 1a (chemoFGFR). The cell-autonomous induction of this chemoFGFR in chain cells effectively triggered the formation of fully mature organs and thus enabled spatial and temporal control of the organogenesis process. Next, we asked what it takes to form an organ de novo. We used a combination of real-time microscopy, single cell tracking, polarity quantification, and mosaic analysis to study the cell behaviors that result from chemoFGFR induction. The picture that emerges from these analyses is that de novo organs form through a genetically encoded self-assembly process that is based on the pattern of chemoFGFR induction. In this scenario, cells expressing chemoFGFR aggregate into clusters and epithelialize as they sort out of non-expressing cells. We found that this sorting process occurs through cell rearrangement and slithering, which involves an extensive remodeling of the cell-cell contacts. Chain cells that do not express chemoFGFR can envelop these chemoFGFR expressing cell clusters and form a rim at the cluster periphery. This multi-stage process leads to the establishment of the inside-outside pattern of de novo organs, which is used as a blueprint for cell differentiation. In summary, in this study we provide insights into the mechanisms involved in the self-assembly of organs from a naïve population of progenitor cells

    Single-cell transcriptomics identifies Keap1-Nrf2 regulated collective invasion in a Drosophila tumor model

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    Apicobasal cell polarity loss is a founding event in epithelial-mesenchymal transition and epithelial tumorigenesis, yet how pathological polarity loss links to plasticity remains largely unknown. To understand the mechanisms and mediators regulating plasticity upon polarity loss, we performed single-cell RNA sequencing of Drosophila ovaries, where inducing polarity-gene l(2)gl-knockdown (Lgl-KD) causes invasive multilayering of the follicular epithelia. Analyzing the integrated Lgl-KD and wildtype transcriptomes, we discovered the cells specific to the various discernible phenotypes and characterized the underlying gene expression. A genetic requirement of Keap1-Nrf2 signaling in promoting multilayer formation of Lgl-KD cells was further identified. Ectopic expression of Keap1 increased the volume of delaminated follicle cells that showed enhanced invasive behavior with significant changes to the cytoskeleton. Overall, our findings describe the comprehensive transcriptome of cells within the follicle cell tumor model at the single-cell resolution and identify a previously unappreciated link between Keap1-Nrf2 signaling and cell plasticity at early tumorigenesis

    Integrating Ecohydraulics in River Restoration: Advances in Science and Applications

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    Rivers have been intensively degraded due to increasing anthropogenic impacts from a growing population in a continuously developing world. Accordingly, most rivers suffer from pressures as a result of increasing dam and weir construction, habitat degradation, flow regulation, water pollution/abstraction, and the spread of invasive species. Science-based knowledge regarding solutions to counteract the effects of river degradation, and melding principles of aquatic ecology and engineering hydraulics, is thus urgently needed to guide present and future river restoration actions. This Special Issue gathers a coherent set of studies from different geographic contexts, on fundamental and applied research regarding the integration of ecohydraulics in river restoration, ranging from field studies to laboratory experiments that can be applied to real-world challenges. It contains 13 original papers covering ecohydraulic issues such as river restoration technologies, sustainable hydropower, fish passage designs and operational criteria, and habitat modeling. All papers were reviewed by international experts in ecology, hydraulics, aquatic biology, engineering, geomorphology, and hydrology. The papers herein well represent the wide applicability of ecohydraulics in river restoration and serve as a basis to improve current knowledge and management and to reduce arguments between different interests and opinions
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