1985 — 1990 |
Hartline, Daniel K |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Quantitative Simulation of Simple Neuronal Nets @ University of Hawaii At Manoa
This research project involves an intensive quantitative study of a small (30-celled) integrative system, the stomatogastric ganglion of the spiny lobster. A detailed quantitative study is being conducted of: 1) activity patterns produced and their reaction to perturbations; 2) repetitive firing properties (pacemaker sensitivity, adaptation, rebound, reaction to perturbations as a function of phase in firing cycle) of each individual neuron type; 3) special cellular properties (plateau-potential production; delaying conductances) of each neuron; 4) synaptic interactions (PSP shape, physiological effectiveness, reversal potential and facilitation effects, electrotonic and "chemotonic" (D.C. chemical) interactions) for all interacting pairs. 5) The principal goals of this will be production of a series of physiologically reliable computer models of the system. As more quantitative data become available, progressively more accurate models will be produced. The models in turn will be used as a means for confirming or rejecting theories on pattern production in the ganglion; for uncovering additional factors in the ganglion that are contributory to its physiological properties; and for investigating the stability of patterns to parameter variation to gain insight into why physiological properties are set as they are.
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1 |
1990 — 1992 |
Hartline, Daniel |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Ionic Mechanisms in Pattern-Generator Neurons
Nerve cells fire electrical impulses by the movement of charged ions through the cell membrane. This ionic current flows through specialized protein channels which may be restricted to a specific type of ion e.g. sodium, potassium or calcium. The amount of current carried by a particular ion and the time it occurs during the nerve impulse are important factors in determining normal function of the nervous system. Since many types of ionic channels and subtypes of channels exist in nature, it is essential to understand their diversity and the ways in which each channel is regulated. One possible new type of channel, carrying the "J-current", has been discovered in the lobster. This current is particularly sensitive to the presence of calcium, which may act as a regulator of channel activity. Studying the J-current is important because it is similar to ionic currents found in mammalian brain. The specific aims of this research are: (1) to identify the ion which is responsible for carrying the J-current, (2) to study its relationship to other ionic currents e.g. potassium current, (3) to analyze the effect of certain drugs on the J-current and (4) to determine its physiological role. The data collected by this research may provide insight into the evolution of ionic channels and the function of ionic channels in higher organisms.
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0.915 |
1990 — 2000 |
Hartline, Daniel Lenz, Petra |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Sensory Reception in Crustacean Zooplankton
9521375 Hartline PROPOSAL ABSTRACT The roles of mechanoreception in predator detection by epipelagic and mesopelagic calanoid copepods (Acartia, Labidocera, Undinula, Euchaeta, Pleuromamma, and Gaussia spp.) will be evaluated from morphological, neurophysiological and behavioral perspectives. The hypothesis to be tested is that escape behavior is triggered by mechanical stimulation of two specific neurons (GAMs) in each antenna. A second focus will be a comparison of conditions eliciting bioluminescent discharge with conditions leading to the stereotypic rapid escape (="jumps"). ***
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0.915 |
1999 — 2005 |
Hartline, Daniel Lenz, Petra |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Collaborative Research: Sensory Reception and Predator Evasion in Crustacean Zooplankton
Researchers evaluate the role of neuromotor processes in predator-evasion by calanoid copepods. These copepods are among the more numerous animals on earth, outnumbering even insects. Despite their importance to oceanic ecosystems, critical understanding is missing on how these animals survive and, indeed, thrive in an ocean full of predators. Investigators are examining, for instance, the rapid, forceful escape behavior in which copepods seem to 'jump' instantaneously away from an approaching predator. They hypothesize that escape behavior exhibits distinctive variations among species, reflecting differences in survival strategies for animals inhabiting different environments in the ocean. Differences in physiological and behavioral characteristics of escape triggered by minute water movements are being correlated with structural features seen in the nervious system, aided by an electron microscope. Investigators are particularly interested in the presence or absence of "myelin," a protective sheathing around nerve cells. Myelin speeds nerve impulse conduction, thus shortening reaction times. Properties of the copepods' nervous systems are being related, too, to sensitivity to water movement, sensitivity to changes in light intensity (mimicking the shadow of a predator), reaction time, movement of appendages, energy production, response duration, swim speed and escape distance. In sum, researchers are providing quantitative information on the copepod's nervous system's unusual sensory and physiological capabilities.
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0.915 |
2005 — 2010 |
Hartline, Daniel Lenz, Petra |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Collaborative Research: Behavioral and Neural Mechanisms For Predator Evasion in Crustacean Zooplankton
In this project the Investigators will examine the ontogeny of predator-evasion behavior in marine calanoid copepods. Neuroethological mechanisms underlying predator-prey interactions are fundamental to the success of planktonic species at all developmental stages. The approach will be interdisciplinary, integrating behavioral, morphological and neurophysiological studies. The specific objectives are: a) to document the development of the escape response in different life stages, from nauplius to adult, and correlate changing escape performance with the development of the sensory, motor and central nervous systems; b) to characterize the effect of variable environmental conditions on the escape of the different life stages; and c) to characterize the development of escape behavior to natural predators. Predation is often the greatest source of mortality for planktonic organisms. Different marine taxa have met this challenge in different ways. In calanoid copepods, it has led to an escape performance matched by few other organisms. Underlying this performance is an array of unusual neuromotor characteristics evolved in response to the predation pressure, including high mechanoreceptive sensitivity, high neuronal firing-frequency capabilities and the occurrence of myelinated nervous systems in about half of all calanoids. Behaviorally it includes fast reactions to mechanical stimuli, high output of muscle energy and high cycle rates of muscle action. Conventional crustacean physiological properties cannot account for copepod escape capabilities. How these animals achieve their remarkable behavioral and physiological performance and how the performance develops from nauplius to adult, are key questions in understanding their success. Because calanoids invest so heavily in escape, the answer to these questions relates strongly to the general issue in all organisms of the role played by the neuromotor system in ecological and evolutionary adaptations. An integrated approach can shed light on this. Focus on the developmental stages will achieve several goals. As for many animal groups, overall predation risk for younger individuals (nauplii and copepodites in copepods) is higher than for adults. Studies of this susceptibility, especially as a neuroethological issue, are relatively few. The proposed work will map out the copepod's developmental strategy for increasing behavioral competence as it matures. Secondly, through studies comparing morphological and physiological features of developmental stages with those in adults, it will help us determine how and when different aspects of the neuromotor systems appear during development and how these correlate with escape performance. Finally, it will give the scientific community a much better understanding of predator-prey interactions in the younger stages. Broader impacts include training of graduate and undergraduate students, as well as providing learning opportunities for the general public and K-12. The project will support the training of two graduate students in marine science, who will be cross-trained in areas of neurophysiology, morphology and behavioral testing. At the level of K-12 and the community we will develop a short video on biological interactions in plankton communities for public presentation and continue to develop and maintain a website on zooplankton sensory ecology
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0.915 |
2009 — 2014 |
Hartline, Daniel Lenz, Petra Castelfranco, Ann |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Comparative and Computational Approaches to the Evolution of Myelin
Rapid behavioral responses to a threat are critical for the survival of animals subjected to high predation risk. Two methods have evolved to shorten the delay between a threatening stimulus and an escape response, both by increasing the conduction velocity of nerve impulses along nerve axons: axon gigantism and myelin sheaths around the axons. Although myelin is best known in vertebrates, it is also found in two crustacean groups. These two invertebrate groups provide opportunities to understand structure-function relationships in myelin because: 1) it is possible to compare closely-related myelinated and non-myelinated forms; 2) nerve cells can be re-identified from one individual to the next, and 3) development of myelin can be tracked in identified cells through all developmental stages. In this project, physiological and computational approaches will be used in a comparative structure-function analysis of myelin in the two crustacean groups: the malacostraca and the calanoid copepods. Myelin has evolved independently in these two groups, yet it shares many features between the two, while being distinct in structure and origin. Some crustaceans transition from completely non-myelinated to fully myelinated nervous systems during development, and thus provide a good model in which to investigate nerve impulse conduction in incompletely formed myelin. Characterizing the commonalities in structure and function for myelin in copepods vs malacostracans will provide new insights into the function and evolution of vertebrate myelin. This study will start answering the question of how and why myelin evolved.
The project will train young undergraduate scientists in interdisciplinary biology and team research, build diversity in science, technology, engineering and math; and provide public access to microscopic images for educational and data mining purposes. Postdoctoral trainees on the project will be educated in the preparation and examination of material for transmission electron microscopy, extracellular electrophysiological stimulation and recording techniques, and computational modeling of neuronal functioning.
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0.915 |
2010 — 2013 |
Sherwood, Alison Steward, Grieg Dunlap, Marilyn Hartline, Daniel Christopher, David |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Mri: Acquisition of Instrumentation For Transmission Electron Microscopy At the University of Hawaii
This Major Research Instrumentation award funds the acquisition of a new transmission electron microscope (TEM) and a new ultramicrotome to support research and training in biology, materials science and engineering at The University of Hawaii at Manoa (UHM). The TEM and ultramicrotome replace aging equipment used by researchers answering fundamental questions in evolution, development, physiology, cell biology, ecology, oceanography, climate change and tropical agriculture. The new instrumentation supports NSF and other funded research in a broad range of biological specializations including: marine viral ecology; biodiversity of marine and freshwater algae; basic plant cell biology; marine invertebrate reproduction, larval settling and metamorphosis; evolution of invertebrate myelin; neural stem cell biology; role of mouse Y chromosome genes in fertilization; and others. Furthermore, the UHM Biological Electron Microscopy Facility uses the new microscope in many educational and outreach activities. The TEM is used for demonstrations for K-12 science classes of local public and private schools, as part of laboratory demonstrations and sessions for undergraduate and graduate university courses in biology and engineering, in a training program for community college faculty and students, other specialty workshops, and for undergraduate and graduate students and postdoctoral associates conducting research with UHM faculty. The results of these research and teaching efforts will be broadly disseminated through abstracts and peer reviewed publications, as well as by active participation of students and faculty at professional meetings
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0.915 |
2012 — 2017 |
Lenz, Petra Hartline, Daniel |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
The Drive to Survive: Copepods Vs Ichthyoplankton
This study will experimentally elucidate the dynamics of predator evasion by different species and life stages of copepod responding to a model larval fish predator. The PIs will use standard and high-speed videographic and cutting-edge holographic techniques. Predator-prey interactions within planktonic communities are key to understanding how energy is transferred within complex marine food webs. Of particular interest are those between the highly numerous copepods and one of their more important predators, the ichthyoplankton (the planktonic larval stages of fishes). The larvae of most fishes are planktivorous and heavily dependent on copepods for food. In general, evasion success increases with age in copepods and decreases with the age of the fish predator. How this plays out in detail is critical in determining predatory attack outcomes and the effect these have on predator and prey survival. To address this problem, different copepod developmental stages will be tested against several levels of predator competence, and the results examined for: 1) the success or failure of attacks for different combinations of predator and prey age class; 2) the kinematics (reaction latencies and trajectory orientation) for escape attempts, successful and unsuccessful, for different age classes of copepod; 3) the hydrodynamic cues generated by different ages and attack strategies of the predator and the sensitivity of different prey stages to these cues; and 4) the success or failure of the predatory approach and attack strategies at each prey stage. The data obtained will be used to inform key issues of zooplankton population dynamics. For the prey these include: predator-evasion capabilities and importance of detection ability, reaction speed, escape speed, escape orientation, and trajectory irregularity; for the predator they are: capabilities and importance of mouth gape size, stealthiness, hydrodynamic disturbance production, and lunge kinematics.
The broader impacts of this project will be 1) improved scientific insight into predator-prey dynamics as they affect the world's fisheries; 2) training of undergraduates, including underrepresented groups, in research (the University of Hawaii at Manoa is a minority-serving institution, and the P.I. is co-director of the UH Minority Access to Research Program, which provides ready access to qualified undergraduates); 3) training undergraduates and graduate students in outreach activities that educate K-12 age children in biodiversity within marine systems, the role of nervous systems in animal behavior, and the scientific method in their study; 4) a technology-oriented outreach and undergraduate education project focused on drawing high-school and early undergraduates into the appreciation of the wonders of animal behavior as revealed by slow-motion (high-speed video) techniques.
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0.915 |
2022 — 2025 |
Lenz, Petra Hartline, Daniel Castelfranco, Ann |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Collaborative Research: Zooplankton Restarts in a High-Latitude Marine Ecosystem: Species-Specific Recruitment and Development in Early Spring
Global climate change and associated extreme weather events are increasingly impacting marine communities at all trophic levels and leading to shifts in the timing of life history events. This project is investigating the annual restart of the spring zooplankton community in the Gulf of Alaska in order to determine the timing of species-specific recruitment and growth. Zooplankton are small pelagic animals that are a critical link between microalgae and protozoans and higher levels in the food web including economically important fishes, birds and marine mammals. While their abundances and species composition have been documented over part of the annual cycle between late spring and fall, this project focuses on winter and early spring. The project integrates traditional methods with modern molecular approaches to characterize the diversity, development, feeding and physiology of zooplankton, especially the early developmental stages of copepods (small crustaceans). The goal is to determine which species are there, how many are present and where they are in the water column, and to reveal indicators of their health. Broader impacts include research training for three graduate students and at least four undergraduates in biological oceanography and physiological ecology. Outreach activities are focusing on broadening the public’s understanding of plankton ecology. An illustrated zooplankton guide for the Gulf of Alaska and plankton module for school teachers and students is being produced in collaboration with the Center for Alaskan Coastal Studies. Other plans include sponsorship of nature-drawing workshops on zooplankton and the production of an Art & Science traveling exhibit. <br/><br/>This project is tracking zooplankton population abundances, species composition and developmental stages through the spring restart in a high-latitude fjord in the northern Gulf of Alaska. While the entire zooplankton community is being characterized, the main focus is on the difficult-to-assess early developmental stages of copepods, which dominate the late spring biomass in the region. Three central hypotheses guide the research: 1) high abundances of copepod nauplii are present before any measurable increases in food in surface waters; 2) species diversity increases between winter and spring, with nauplii from large lipid-rich capital-breeding species appearing first, followed by those from income- and hybrid-strategy species and finally nauplii that emerge from dormant eggs; 3) prior to the appearance of food resources, nauplii from capital-breeding species conserve resources by delaying development and entering a state of dormancy in the second and third naupliar stages. The project entails intensive depth-stratified field sampling to characterize the wild community, in combination with laboratory experiments on nauplii to determine their responsiveness to food. The prey are being characterized by measuring chlorophyll a, dietary and prey community DNA sequencing and flow cytometry to establish diversity and abundances. Size-fractionated zooplankton samples are being analyzed using microscopy and community DNA sequencing to ascertain species diversity, developmental stage distribution and abundances. Feeding activity is being measured using dietary DNA sequencing of nauplii followed by comparisons with the prey field. Dormancy in nauplii is being determined by differential gene expression of target genes (RT-qPCR) and high-throughput sequencing of mRNA of individuals (transcriptomics) and community samples (meta-transcriptomics). Short-term and long-term effects of food availability on dormancy, development and growth are being quantified in laboratory experiments. Broader impacts are focused on training of students in interdisciplinary research and state-of-art techniques, and public outreach to introduce plankton ecology to broader audiences.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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0.915 |