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Articles 991 - 1020 of 1043

Full-Text Articles in Biology

Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher May 1994

Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher

Faculty Publications

The purpose of this study was to further our understanding of the role of particle-associated bacteria in phytoplankton degradation in the Chesapeake Bay, USA, and to identify environmental parameters that control production by free and particle-associated bacteria. Surface and bottom waters at 10 stations along the length of the Bay were sampled over a 2 yr period. Samples were analyzed for temperature, salinity, chlorophyll, phaeophytin, particulate protein, thymidine incorporation (an estimate of bacterial growth rate), and bacterial total direct counts. Results demonstrated that freeliving bacteria were responsible for most of the total bacterial production, which was correlated with temperature and …


Multiple Modes Of Asexual Reproduction By Tropical And Subtropical Sea Star Larvae: An Unusual Adaptation For Genet Dispersal And Survival, William Jaeckle Feb 1994

Multiple Modes Of Asexual Reproduction By Tropical And Subtropical Sea Star Larvae: An Unusual Adaptation For Genet Dispersal And Survival, William Jaeckle

Scholarship

Sea star larvae (Echinodermata: Asteroidea), collected from the subtropical Northwest Atlantic Ocean, exhibited three distinct modes of asexual reproduction. A number of different bipinnariae and brachiolariae reproduced by paratomous cloning of the posterolateral arms. This morphogenesis was identical to that of larvae assignable to the genus Luidia. A second mode of asexual reproduction involves the autotomization of an anterior portion of the preoral lobe. Primary larvae with preoral lobes of varying sizes and free-swimming preoral lobes of various stages of morphological development were simultaneously collected. The free-swimming preoral lobes developed complete digestive systems and ultimately assumed the form of …


Penetration Of The Pz-Peptide Through The Various Membranes Of The Gastrointestinal Tract, Jyun "Jay" Nakamura Jan 1994

Penetration Of The Pz-Peptide Through The Various Membranes Of The Gastrointestinal Tract, Jyun "Jay" Nakamura

Whittier Scholars Program

The use of the oral drugs dates back to the beginning of recorded time. Since the modern era, doctors and researchers have found the various physiological pathways by which they operate and function. Within the past fifty years, this research has proceeded to the cellular and molecular levels. Researchers have found that the drugs target specific components of the infected cells. These drugs interact by binding to three different types of target molecules. The chemicals target receptors found on extracellular proteins, macromolecules like enzymes, transport molecules, nucleic acids, and membrane lipids. With these new findings, new techniques and equipment have …


Rates Of Energy Consumption And Acquisition By Lecithotrophic Larvae Of Bugula Neritina (Bryozoa: Cheilostomata), William Jaeckle Jan 1994

Rates Of Energy Consumption And Acquisition By Lecithotrophic Larvae Of Bugula Neritina (Bryozoa: Cheilostomata), William Jaeckle

Scholarship

Lecithotrophic larvae of the cheilostome bryozoan, Bugula neritina (L.), lose metamorphic competence 12 to 24 h after release from the maternal zooid. The high respiration rate of newly released larvae (mean=306.3 pmol O2 larva-1 h-1, range= 149.3 to 466.6, n=18 trials, 22.5 °C) from adults collected at Link Port, Fort Pierce, Florida during the winter/spring of 1990-1991 reflects their active swimming behavior. The average energy con¬tent per larva was 15.24 mJ (range: 13.35 to 20.17 mJ ind-1, n=5 groups). If all cells have an identical energy content and metabolic rate, then 2 and 20% …


Decomposition Of Senescent Blades Of The Seagrass Halodule Wrightii In A Subtropical Lagoon, Stephen Opsahl, Ronald Benner Apr 1993

Decomposition Of Senescent Blades Of The Seagrass Halodule Wrightii In A Subtropical Lagoon, Stephen Opsahl, Ronald Benner

Faculty Publications

Senescent blades from the seagrass Halodule wrightii Aschers were suspended in the water column of Laguna Madre (Texas, USA) for a period of 419 d, representing the longest seagrass decomposition study to date. The initial stage of decomposition was characterized by a rapid loss of organic matter (36 % in 24 d) attributed to leaching. A total of 76 % of the organic matter from seagrass tissues was lost by the end of the decomposition period. Of the major bulk constituents measured, neutral sugars were most abundant and accounted for 23 % of the ash-free dry wt of the initial …


Bioremediation: A New Technology Using Inhabitants Of The Soil, Matthew Fields Jan 1993

Bioremediation: A New Technology Using Inhabitants Of The Soil, Matthew Fields

Mahurin Honors College Capstone Experience/Thesis Projects

Bioremediation is the use of microorganisms to clean the environment contaminated with various pollutants such as chemical wastes and petroleum -based products. The microbes use the pollutants as their carbon source and by doing so the contaminants are broken down. This paper examined the numbers of indigenous microorganisms in soil contaminated with diesel fuel and oil. Contaminant-degrading microbes were isolated and enumerated using phenanthrene in mineral media. The breakdown of phenanthrene was used as an indicator for contaminant degradation. The effects of aeration and the addition of nutrients on bioremediation processes was also studied. Soil samples used in the performed …


Denitrification And Oxygen Consumption In Sediments Of Two South Texas Estuaries, Won Bae Yoon, Ronald Benner Dec 1992

Denitrification And Oxygen Consumption In Sediments Of Two South Texas Estuaries, Won Bae Yoon, Ronald Benner

Faculty Publications

Spatial and temporal variations in rates of denitrification and oxygen consumption were measured in sediments of the Nueces and Guadalupe Estuaries in southern Texas, USA. Denitrification rates varied from 4.0 to 71.1 µmol N2 m-2 h-1 in the Nueces Estuary and from 4.6 to 34.7 µmol N2 m-2 h-1 in the Guadalupe Estuary. Denitrification accounted for 29 to 80% of total benthic N flux in the study areas. Oxygen consumption rates ranged from 176 to 818 µmol O2 m-2 h-1 in Nueces Estuary and from 208 to 550 µmol O2 …


Bacterial Numbers And Activity, Microalgal Biomass And Productivity, And Meiofaunal Distribution In Sediments Naturally Contaminated With Biogenic Bromophenols, Charles C. Steward, James L. Pinckney, Yvette Piceno, Charles R. Lovell Dec 1992

Bacterial Numbers And Activity, Microalgal Biomass And Productivity, And Meiofaunal Distribution In Sediments Naturally Contaminated With Biogenic Bromophenols, Charles C. Steward, James L. Pinckney, Yvette Piceno, Charles R. Lovell

Faculty Publications

Sediment cores were collected inside and outside of a bed of a bromophenol-producing marine polychaete, Notomastus lobatus, and examined for impact of the bromophenols on sediment microflora and meiofauna around N. lobatus burrows. No significant differences were found between microbial parameters measured inside and outside of the N. lobatus bed. Integrated 6 cm cores taken adjacent to N. lobatus burrows contained 1.2 x 109 bacteria ml-1. Cell numbers were similar at control sites within the bed, but away from burrows, and not significantly different from cell numbers (1.0 X 109 cells ml-1) at a …


Enhanced Bacterioplankton Production And Respiration At Intermediate Salinities In The Mississippi River Plume, Gerardo Chin-Leo, Ronald Benner Oct 1992

Enhanced Bacterioplankton Production And Respiration At Intermediate Salinities In The Mississippi River Plume, Gerardo Chin-Leo, Ronald Benner

Faculty Publications

Bacterial abundance and production (thymidine and leucine incorporation) were measured along a salinity gradient from the Mississippi River (0 %0) to the open waters of the Gulf of Mexico (36 %0) during July-August 1990 and February 1991. Bacterial production in surface waters was maximal at intermediate salinities (15 to 30 %0). Nutrient enrichment experiments suggested that bacterial growth near the outflow of the river was C limited whereas bacteria in plume waters of intermediate salinities were P and N limited. Rates of plankton community oxygen demand measured during winter were also maximal at intermediate …


A Brief Introduction To Aims And Methods For Image Processing Of Electron Micrographs Of Biological Specimens, Murray Stewart Jan 1992

A Brief Introduction To Aims And Methods For Image Processing Of Electron Micrographs Of Biological Specimens, Murray Stewart

Scanning Microscopy

A common problem with electron micrographs of biological objects is that fine details are usually faint and, moreover, tend to be obscured by background noise from stain and support film. Filtering is a useful way to improve the signal-to-noise ratio and is particularly important when trying to detect small changes (conformational or due to labelling) or when examining frozen hydrated objects, where the statistical definition of the image has been reduced because of the low-dose conditions needed to prevent radiation damage. Filtering can also be used to address the superposition effects that result from the large depth of focus of …


Effects Of Tidal Stage And Sun Angles On Intertidal Benthic Microalgal Productivity, James L. Pinckney, R. G. Zingmark Sep 1991

Effects Of Tidal Stage And Sun Angles On Intertidal Benthic Microalgal Productivity, James L. Pinckney, R. G. Zingmark

Faculty Publications

Motile benthic diatoms exhibit rhythmic vertical migrations that are influenced by tidal and light cycles. As a consequence of these periodic migrations, corresponding periodicities in benthic microalgal production should occur. Using oxygen microelectrodes, hourly measurements of microalgal production were obtained from subaerially exposed cores collected from low-intertidal muddy sediments in North Inlet estuary, South Carolina, USA Microalgal productivity at low tide was twice that at high tide (mean difference 52 %) and was significantly correlated with diurnal and tidal periodicities (r2 = 0.41; p < 0.0001). Production values ranged from 28.0 to 460.5 µmol O2 mg chl a-1 h-1 and maximum rates were achieved during mid-afternoon low …


Dynamics Of Bacterioplankton Abundance And Production In Seagrass Communities Of A Hypersaline Lagoon, Gerardo Chin-Leo, Ronald Benner Jul 1991

Dynamics Of Bacterioplankton Abundance And Production In Seagrass Communities Of A Hypersaline Lagoon, Gerardo Chin-Leo, Ronald Benner

Faculty Publications

The significance of bacterioplankton in the flow of carbon and energy and in trophic dynamics of the upper Laguna Madre, Texas (USA), was estimated by measuring bacterioplankton abundance and production over an 18 mo period and over several diel cycles. Bacterioplankton production was estimated from incorporation rates of thymidine (DNA synthesis) and leucine (protein synthesis). These independent inhces of bacterial growth were generally in agreement and yielded nearly identical annual estimates of bacterial production (25.24 g C m-2 yr-1 based on thymidine and 25.12 g C m-2 yr-1based on leucine). Assuming a 30 % growth …


Electrophysiology, Cell Calcium, And Mechanisms Of Hepatocyte Volume Regulation, Walid E. Khalbuss Aug 1990

Electrophysiology, Cell Calcium, And Mechanisms Of Hepatocyte Volume Regulation, Walid E. Khalbuss

Electronic Theses and Dissertations

The electrophysiologic technique (Reuss, L., Proc. Natl. Acad. Sci. USA 82:6014, 1985) was modified to measure changes in steady-state hepatocyte volume during osmotic stress. Hepatocytes in mouse liver slices were loaded with tetramethylammonium ion (TMA$\sp{+}$) during transient exposure of cells to nystatin. Intracellular TMA$\sp{+}$ activity (a$\sp{\rm i}\sb{\rm TMA}$) was measured with TMA$\sp{+}$-sensitive, double-barreled microelectrodes. Loading hepatocytes with TMA$\sp{+}$ did not change their membrane potential (V$\sb{\rm m}$), and under steady-state conditions a$\sp{\rm i}\sb{\rm TMA}$ remained constant over 4 min in single impalements. Hyperosmotic solutions (50, 100, & 150 mM sucrose added to media) and hyposmotic solutions (sucrose in media reduced by …


Fisheries Research Report No 88 - A Synopsis Of The Biology And The Exploitation Of The Australiasian Pilchard, Sardinops Neopilchardus (Steindachner) Part 1: Biology, W. J. Fletcher May 1990

Fisheries Research Report No 88 - A Synopsis Of The Biology And The Exploitation Of The Australiasian Pilchard, Sardinops Neopilchardus (Steindachner) Part 1: Biology, W. J. Fletcher

Fisheries Research Reports

There have been a large number of studies which relate to the biology and exploitation of the Australian pilchard, Sardinops neopilchardus. Much of the data, however, are located in journals which are hard to obtain, or in unpublished reports, and theses. With the increase in catch of pil­chards, particularly in Western Australia, a collation of all the available knowledge pertaining to pilchards in Australia and New Zealand was desired to help with the planning of future research into the Western Australian stocks of this species. This report contains all the information located on the biology of Sardinops neopilchardus, a companion …


Amino Acid Uptake And Metabolism By Larvae Of The Marine Worm Urechis Caupo (Echiura), A New Species In Axenic Culture, William Jaeckle, Donal T. Manahan Jun 1989

Amino Acid Uptake And Metabolism By Larvae Of The Marine Worm Urechis Caupo (Echiura), A New Species In Axenic Culture, William Jaeckle, Donal T. Manahan

Scholarship

Axenic (bacteria-free) larval cultures of the marine echiuran worm, Urechis caupo, were reliably obtained by aseptically removing gametes directly from the gamete storage organs. Trochophore larvae only removed neutral amino acids from seawater as measured by high-performance liquid chromatography (HPLC). There was no detectable uptake, as measured by HPLC, of acidic or basic amino acids. Kinetic analysis showed that the transport system for alanine in 4-day-old larvae had a Kt of 4-6 μM and a Jmax of 9-10 pmol larva-1 h-1. Following a 50-min exposure, the majority of the radio-activity (95%) from 14 …


Age And Growth Of King Mackerel, Scomberomorus Cavalla, From The Atlantic Coast Of The United States, Mark R. Collins, David J. Schmidt, C. Wayne Waltz, James L. Pinckney Jan 1989

Age And Growth Of King Mackerel, Scomberomorus Cavalla, From The Atlantic Coast Of The United States, Mark R. Collins, David J. Schmidt, C. Wayne Waltz, James L. Pinckney

Faculty Publications

Whole sagittae from 683 and sectioned sagittae from 773 "adult" (age> 0 ; 437-1.310 mm FL), and lapilli from 29 larval (2-7 mm SL) and 69 young-of-the-year (79-320 mm FL) king mackerel, were examined. All fish were from waters off the Atlantic coast of the southeastern United States (Cape Canaveral, Florida to Cape Fear. North Carolina). Back-calculated lengths at ages and von Bertalanffy growth equations were calculated from both whole and sectioned sagittae. Ages determined from sectioned sagittae were significantly greater than ages determined from whole sagittae, and the magnitude of the difference increased with age (from sections). Rings on …


Diseases And Plant Population Biology, Nancy J. Huntly, R Inouye Jan 1988

Diseases And Plant Population Biology, Nancy J. Huntly, R Inouye

Biology Faculty Publications

No abstract provided.


Adaptation Of Striped Bass To Sea Water Following Direct Transfer From Freshwater: Morphological, Biochemical, And Physiological Parameters, Judy A. King May 1987

Adaptation Of Striped Bass To Sea Water Following Direct Transfer From Freshwater: Morphological, Biochemical, And Physiological Parameters, Judy A. King

Electronic Theses and Dissertations

There has been heightened interest in the biology of striped bass (Morone saxatilis) because of increased pollution in their native spawning grounds and because of their extensive use in landlocked sport fisheries. Their euryhalinity makes them an excellent species for osmoregulation studies. The objective of this research was to study the rate of adaptation of striped bass gills to sea water (3% salt) after direct transfer from freshwater using biochemical (ion transport enzyme levels), physiological (chloride efflux), and ultrastructural methods. Striped bass have specialized osmoregulatory cells located on the interlamellar and afferent surfaces of their gill filaments as shown by …


Quantifying Spatial Patterns Of Overgrowth In Epibenthic Communities, David S. Wethey, Linda J. Walters Mar 1986

Quantifying Spatial Patterns Of Overgrowth In Epibenthic Communities, David S. Wethey, Linda J. Walters

Faculty Publications

A method is presented that allows rapid and accurate measurement of changes in the spatial pattern of space occupation in encrusting organisms. The boundaries of organisms are represented as polygons, and geometric difference calculations are used to establish the perimeters of the areas gained or vacated between sampling dates. The influence of interspecific interactions on occupation of space is also quantified: geometric intersection calculations are used to define the perimeters of the areas gained or lost in overgrowth interactions. A method is presented for estimating the sampling frequency necessary for detection of significant changes in occupation of space. The method …


Schistosomiasis A Public Health Concern, Greg Maciel Jan 1986

Schistosomiasis A Public Health Concern, Greg Maciel

Whittier Scholars Program

This project is a research paper on the parasitic disease, schistosomiasis. Schistosomiasis can cause illness, disability, and in some cases, death. Schistosomiasis survives in climates that range from tropical to temperate. The disease is most prevalent in underdeveloped areas where sanitation is poor. These underdeveloped areas have little money for treatment and controls. And because the disease prevents people from working, the economy of these infected areas can suffer. Without eradication efforts, schistosomiasis can be spread to the whole population. In trying to control schistosomiasis people are looking for the most thorough and least expensive methods. This paper will be …


Microbial Degradation Of The Leachable And Lignocellulosic Components Of Leaves And Wood From Rhizophora Mangle In A Tropical Mangrove Swamp, Ronald Benner, Robert E. Hodson May 1985

Microbial Degradation Of The Leachable And Lignocellulosic Components Of Leaves And Wood From Rhizophora Mangle In A Tropical Mangrove Swamp, Ronald Benner, Robert E. Hodson

Faculty Publications

Preparations of uniformly [14C] labeled mangrove leaves and specifically radiolabeled [14C-lignin] lignocelluloses and [14C -polysaccharide]lignocelluloses from mangrove leaves and wood were used in experiments to determine the microbial rates of mineralization of the leachable and lignocellulosic components of mangrove detritus in aerobic and anaerobic sediments of a tropical mangrove swamp. The bulk of the leachable fraction from mangrove leaves was mineralized relatively rapidly and was assimilated into microbial biomass with high efficiency (30 %). In contrast, rates of mineralization of the lignocellulosic component of mangrove leaves and wood were 10fold lower than mineralization rates …


Rearrangement Of The Keratin Cytoskeleton After Combined Treatment With Microtubule And Microfilament Inhibitors, Loren W. Knapp, W. Michael O'Guin, Roger H. Sawyer Dec 1983

Rearrangement Of The Keratin Cytoskeleton After Combined Treatment With Microtubule And Microfilament Inhibitors, Loren W. Knapp, W. Michael O'Guin, Roger H. Sawyer

Faculty Publications

In addition to containing microtubule and microfilament systems, vertebrate epithelial cells contain an elaborate keratin intermediate-filament cytoskeleton. Little is known about its structural organization or function. Using indirect immunofluorescence microscopy with an antikeratin antiserum probe, we found that destabilization of microtubules and microfilaments with cytostatic drugs induces significant alterations in the cytoskeletal organizationof keratin filaments in HeLa and fetal mouse epidermal cells. Keratin filament organizationwas observed to undergo a rapid (1-2 h) transition from a uniform distribution to an open lattice of keratin fibers stabilized by membrane-associated focal centers . Since addition of any one drug alone did not elicit …


A Revision Of The North American Species In The Genus Euodynerus (Hymenoptera: Eumenidae), Ali Shallan Moalif May 1982

A Revision Of The North American Species In The Genus Euodynerus (Hymenoptera: Eumenidae), Ali Shallan Moalif

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Twenty-eight species of Euodynerus Dalla Torre are recognized from the Nearctic Region, of which one is Holarctic. Literature on the biology of fourteen species is reviewed and new biological information discussed for four species. The phylogenetic relationships of the genus Euodynerus to other genera and the classification and relationships of the species of Euodynerus are discussed. Seven subgenera are recognized of which four are new: Euodynerus, Pareuodynerus Bluethgen, Leucodynerus Bohart, Annodynerus new subgenus, Gonodynerus n. subgenus, Holodynerus n. subgenus and Plecodynerus n. subgenus. Their comparative morphology, phylogeny, and distrubution are discussed. Larval instars of E. hidalgo (Saussure), E. scutellaris …


A Limnological Study Of 43 Selected Maine Lakes, Derrill J. Cowing, Matthew Scott Jan 1980

A Limnological Study Of 43 Selected Maine Lakes, Derrill J. Cowing, Matthew Scott

Maine Collection

A Limnological Study of 43 Selected Maine Lakes

by Derrill J. Cowing and Matthew Scott

U.S. Geological Survey : Water-Resources Investigations 80-69

Prepared in cooperation with the Maine Department of Environmental Protection

U.S. Geological Survey, 26 Ganneston Drive, August, Maine 04330


"Biological Determinism As A Social Weapon", Richard C. Lewontin Jan 1976

"Biological Determinism As A Social Weapon", Richard C. Lewontin

Special Collections: Oregon Public Speakers

No abstract provided.


Karyology And Sex In Clematis Ligusticifolia Nutt. (Ranunculaceae), Darrel A. White Jan 1973

Karyology And Sex In Clematis Ligusticifolia Nutt. (Ranunculaceae), Darrel A. White

All Master's Theses

An investigation was conducted to determine the relationship between sex and karyology in Clematis ligusticifolia Nutt. (Ranunculaceae), a dioecious perennial.

Chromosome number and karyology of this species are discussed and a review of some of the major works of previous investigators of sex determinism in dioecious angiosperms is included.


Effects Of The Cle Elum Reservoir On The Ephemeroptera (Mayflies) Of The Cle Elum River, David Bruce Ainsworth Aug 1971

Effects Of The Cle Elum Reservoir On The Ephemeroptera (Mayflies) Of The Cle Elum River, David Bruce Ainsworth

All Master's Theses

The purpose of this study was to determine the physical and chemical effects of the Cle Elum Reservoir on the Cle Elum River and to evaluate these effects in respect to the Ephemeroptera of the Cle Elum River. Specific objectives were: (1) To determine the effects of the reservoir on current velocity, volume of flow, turbidity, and temperature. (2) To determine the effects of the reservoir on alkalinity, hardness, dissolved oxygen, and pH. (3) To evaluate the effects of the reservoir on the Ephemeroptera of the Cle Elum River.


The Riparian Vegetation Of Swauk Creek, Edward L. Schneider Aug 1971

The Riparian Vegetation Of Swauk Creek, Edward L. Schneider

All Master's Theses

An investigation was made to document the structure and composition of the flora along Swauk Creek, a riparian transect into Central Washington's Cascade Range. Distributions of the major species are discussed and a key has been constructed to facilitate identification of the riparian associations.


Breeding Biology Of The Sage Thrasher, John Wayne Gooding Aug 1970

Breeding Biology Of The Sage Thrasher, John Wayne Gooding

All Master's Theses

The sage thrasher, Oreoscontes montanus (Townsend), is a common bird that breeds throughout the sage brush areas of the Great Basin and from northern Arizona to southern Saskatchewan. Although it is a fairly common and conspicuous bird, almost nothing about its life history has been published. This study was conducted in central Washington during the spring and summer of 1969 and the spring and early summer of 1970. During the 1969 season, emphasis was placed on finding and tracing the phenologies of as many nests as possible in order to determine the timing of the nesting cycle. During the 1970 …


A Biological Investigation On Plethodon Larselli, Charles Oliver Holmes Aug 1969

A Biological Investigation On Plethodon Larselli, Charles Oliver Holmes

All Master's Theses

The purpose of this study is to increase the presently-lacking biological knowledge of P. larselli. A study was made, therefore, on this species relative to its geographical distribution, habitat, dehydration and rehydration rates, response to induction with varying concentrations of a gonadotropic hormone, and blood serum analysis by cellulose acetate electrophoresis. In addition, the findings of this investigation will help elucidate the relationship between P. larselli and P. vehiculum.