Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Institution
- Publication
- Publication Type
Articles 1 - 9 of 9
Full-Text Articles in Life Sciences
Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet
Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet
Scholarship
Dichromate oxidation is a simple technique that is often used to estimate the energy content of eggs in studies of marine invertebrate life histories (1). We used this method to measure the energy contents of the eggs of 12 species of marine annelids. In combination with measures of egg ash-free dry weight (AFDW), these data yielded estimates of AFDW-specific energy density that were mostly lower than the average weight-specific energy density of carbohydrates. This seemed unlikely to be correct, as invertebrate eggs typically contain little carbohydrate and instead are composed primarily of energy-dense protein and lipid (1, 2). After validating …
Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet
Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet
William Jaeckle
Dichromate oxidation is a simple technique that is often used to estimate the energy content of eggs in studies of marine invertebrate life histories (1). We used this method to measure the energy contents of the eggs of 12 species of marine annelids. In combination with measures of egg ash-free dry weight (AFDW), these data yielded estimates of AFDW-specific energy density that were mostly lower than the average weight-specific energy density of carbohydrates. This seemed unlikely to be correct, as invertebrate eggs typically contain little carbohydrate and instead are composed primarily of energy-dense protein and lipid (1, 2). After validating …
A Patch Hath Smaller Patches: Delineating Ecological Neighborhoods For Parasites, Derek Zelmer, John R. Seed
A Patch Hath Smaller Patches: Delineating Ecological Neighborhoods For Parasites, Derek Zelmer, John R. Seed
Faculty Publications
Use of the host individual as a boundary for parasite populations and communities provides an unambiguous spatial unit that is useful for pattern description, but this framework precludes consideration of the host landscape and within-host population dynamics. Recognizing host individuals as spatially and temporally complex landscapes requires modified concepts of parasite populations and communities. An outline of the currently accepted hierarchies of parasite populations and communities is provided on the basis of ecological neighborhoods that are delineated by discrete habitat patches or functional dynamics (or both), as opposed to host individuals. This parasite-based framework accommodates consideration of both within- and …
Individual Cell Growth Rates Of Marine Bacteria, Measured By Bromodeoxyuridine Incorporation, Koji Hamasaki, Richard A. Long, Farooq Azam
Individual Cell Growth Rates Of Marine Bacteria, Measured By Bromodeoxyuridine Incorporation, Koji Hamasaki, Richard A. Long, Farooq Azam
Faculty Publications
We tested the application of 5-bromo-2’-deoxyuridine (BrdU), a thymidine analogue that becomes incorporated into DNA during growth, to measure growth rates of individual marine bacteria cells. Immunocytochemical detection of BrdU incorporation into bacterial DNA has the potential for single-cell-based growth measurement. Optimized procedure for immunocytochemistry was applicable to 14 marine heterotrophic bacterial isolates belonging to g-proteobacteria, α-proteobacteria, Cytophaga-Flavobacterium-Bacteroides (CFB) group and Gram-positive bacteria. The relationship between cell-specific fluorescence intensity and specific growth rate was linearly correlated among CFB group isolates, which indicated a potential of the method for quantitative measurement. Analysis of the detection limit indicated …
Particle Removal Rates By The Mud Shrimp Upogebia Pugettensis, Its Burrow, And A Commensal Clam: Effects On Estuarine Phytoplankton Abundance, Blaine D. Griffen, Theodore H. Dewitt, Chris Langdon
Particle Removal Rates By The Mud Shrimp Upogebia Pugettensis, Its Burrow, And A Commensal Clam: Effects On Estuarine Phytoplankton Abundance, Blaine D. Griffen, Theodore H. Dewitt, Chris Langdon
Faculty Publications
The burrowing shrimp Upogebia pugettensis is an abundant intertidal invertebrate of Pacific Northwest, USA bays and estuaries where it lives commensally with the bivalve Cryptomya californica. Suspension-feeding activities by the shrimp and by its commensal clam, as well as particle settlement within the burrow, represent 3 different components that could remove phytoplankton from water drawn into shrimp burrows. These 3 components together comprise what we call the ‘U. pugettensis shrimp-burrow complex’. In laboratory experiments, we measured particle removal by each of these components. Our results indicated that U. pugettensis itself is responsible for filtering the majority of phytoplankton removed …
Variability In Broods Of The Seastar Leptasterias Aequalis, William B. Jaeckle, Brian L. Bingham, Kehualani Giles
Variability In Broods Of The Seastar Leptasterias Aequalis, William B. Jaeckle, Brian L. Bingham, Kehualani Giles
Scholarship
Enormous variation exists in the reproductive output of marine invertebrates (e.g., in the numbers of em¬bryos produced, the volumes of embryos, and the energy that they contain). It is not clear why there is such great variability or what the population-level consequences are. We sampled a population of the brooding seastar Leptasterias aequalis (Stimpson, 1862) to collect basic information on brood sizes, embryo volume, and embryo energy content with a goal to better understand the reproductive ecology of this species. We collected brooding females in February and again in April. We measured the size of their broods and sampled the …
Scale Model Of A Soil Aggregate And Associated Organisms: A Teaching Tool For Soil Ecology, Mary Anne Bruns, Loren B. Byrne
Scale Model Of A Soil Aggregate And Associated Organisms: A Teaching Tool For Soil Ecology, Mary Anne Bruns, Loren B. Byrne
Arts & Sciences Faculty Publications
Soil is a complex habitat for diverse biota. A significant challenge in teaching soil ecology is our inability to observe organisms as they live and interact in the soil. The objective of this article is to describe an interactive class project to help students visualize the sizes of different groups of soil organisms and to relate these to soil structural components. This project was carried out by students in an upper-level undergraduate soil ecology class. It involved the design and construction of a 4000× scale model of a soil aggregate and its associated organisms. The body of the model was …
The Cortical Microtubule Array: From Dynamics To Organization, Ram Dixit, Richard Cyr
The Cortical Microtubule Array: From Dynamics To Organization, Ram Dixit, Richard Cyr
Biology Faculty Publications & Presentations
Cortical microtubules (CMTs) are essential for normal plant morphogenesis because they affect the axes of cell elongation and predict the placement of cell division planes. The function of the CMTs is intimately linked to their organizational state, which is subject to spatial and temporal modifications by developmental and environmental cues. CMT assembly dynamics govern when, where, and how microtubules appear in a cell's cortex, and the regulation of these properties affects their organization. However, the principles that link microtubule assembly dynamics to cortical array organization and reconfiguration are not well understood. This essay focuses on recent advances in the understanding …
Encounters Between Dynamic Cortical Microtubules Promote Ordering Of The Cortical Array Through Angle-Dependent Modifications Of Microtubule Behavior, Ram Dixit, Richard Cyr
Encounters Between Dynamic Cortical Microtubules Promote Ordering Of The Cortical Array Through Angle-Dependent Modifications Of Microtubule Behavior, Ram Dixit, Richard Cyr
Biology Faculty Publications & Presentations
Ordered cortical microtubule arrays are essential for normal plant morphogenesis, but how these arrays form is unclear. The dynamics of individual cortical microtubules are stochastic and cannot fully account for the observed order; however, using tobacco (Nicotiana tabacum) cells expressing either the MBD-DsRed (microtubule binding domain of the mammalian MAP4 fused to the Discosoma sp red fluorescent protein) or YFP-TUA6 (yellow fluorescent protein fused to the Arabidopsis alpha-tubulin 6 isoform) microtubule markers, we identified intermicrotubule interactions that modify their stochastic behaviors. The intermicrotubule interactions occur when the growing plus-ends of cortical microtubules encounter previously existing cortical microtubules. Importantly, the outcome …