Life Sciences Commons^™

Daughter Cells Of Saccharomyces Cerevisiae From Old Mothers Display A Reduced Life Span, Nicanor Austriaco, Brian K. Kennedy, Leonard Guarente

Biology Faculty Publications

The yeast Saccharomyces cerevisiae typically divides asymmetrically to give a large mother cell and a smaller daughter cell. As mother cells become old, they enlarge and produce daughter cells that are larger than daughters derived from young mother cells. We found that occasional daughter cells were indistinguishable in size from their mothers, giving rise to a symmetric division. The frequency of symmetric divisions became greater as mother cells aged and reached a maximum occurrence of 30% in mothers undergoing their last cell division. Symmetric divisions occurred similarly in rad9 and ste12 mutants. Strikingly, daughters from old mothers, whether they arose …

Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner

Faculty Publications

Rates of benthic denitrification, oxygen consumption and nutrient regeneration were measured during winter, spring and summer in Galveston Bay (Texas, USA) sediments. Denitrification ranged from 0 to 47 µmol N₂ m^-2 h^-1 with maximal rates generally occurring in the summer and the upper estuary. Oxygen consumption rates ranged from 38 µmol O₂ m^-2 h^-1 in the winter to 353 µmol O₂ m^-2 h^-1 in the summer and were correlated with denitrification rates. Variations in bay water temperature accounted for 52 % of the variability associated with denitrification rates whereas only 28% …

The Identification, Distribution, Impacts, Biology And Management Of Noxious Rangeland Weeds, Roger L. Sheley

All U.S. Government Documents (Utah Regional Depository)

This document provides a discussion of the biology and management of exotic rangeland weeds which are a threat to native ecosystems of the western United States. Chapter 1 describes a generalized approach for managing noxious weed infested rangeland, while Chapter 2 focuses on preventing noxious weed invasion. In some cases, noxious weeds readily invade riparian areas, and because of the sensitive nature of these ecosystems Chapter 3 is devoted to riparian weed management. The following 13 chapters describe the identification, origin, history, distribution, potential invasion, impacts, biology and ecology, and management of specific noxious rangeland weeds.

1994 Ieee Computer Society Press Reprint, James W. Brunt

Long Term Ecological Research Network

Effective management of ecological research data can insure the security and accessibility of data that cannot be collected again under the same conditions and plays a key role in every aspect of the research project from experimental design to publication. Commercial relational database management software, developed an adequate solution for long-term scientific data management. An archive file format provides the standard around which a data file management system is implemented. The system works within the parameters of existing components of the operating system software. Data filters and data engines are used to communicate data to and from applications. This paper …

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 …

Lter Correspondence & Letters, Jerry F. Franklin

Long Term Ecological Research Network

1st. Letter written by Jerry F. Franklin, chair of LTER Network, addressed to David Greenland of the department of Geography. Franklin extends an invitation to the upcoming Coordinating Committee meeting taking place from October 19-21.

2nd. Letter written by Jerry F. Franklin, chair of LTER Network, addressed to Joshua Greenberg of he College of Forest Resources. Franklin extends an invitation to the upcoming Coordinating Committee meeting taking place from October 19-21.

3rd. Letter written by Jerry F. Franklin, chair of LTER Network, he writes on the significant decisions taken place over the LTER/CC meeting held on April 22-24.

4th. Letter …

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 …

G94-1208 Managing The Alfalfa Weevil, Stephen D. Danielson, Thomas E. Hunt, Keith J. Jarvi

University of Nebraska-Lincoln Extension: Historical Materials

The identification and life cycle of the alfalfa weevil are discussed along with scouting techniques, economic thresholds, and other integrated pest management tactics.

The alfalfa weevil is the primary insect pest of alfalfa in Nebraska. Management is essential to reduce crop losses, particularly during years when weevil infestation is high. Because there also are years when weevil damage is economically unimportant, it is necessary for growers to become familiar with sampling procedures, management guidelines, and control recommendations so control techniques are not used unnecessarily.

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% …

G94-1220 Controlling Ticks, John B. Campbell, Gustave D. Thomas

University of Nebraska-Lincoln Extension: Historical Materials

Identification and control of ticks common to Nebraska.

Ticks are members of the same phylum (Arthropoda) of the animal kingdom as insects, but are in a different class (Arachnida). The main difference is the body of a tick is composed of only two sections while insect bodies have three sections.

There are over 800 species of ticks, 100 of which are important to man and animals because of economic losses or disease transmission. Fortunately in the United States, only about 12 species are economically important because they transmit disease organisms (viral, bacterial, protozoan, and rickettsial) or cause economic losses to …