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Full-Text Articles in Life Sciences

Individual Cell Growth Rates Of Marine Bacteria, Measured By Bromodeoxyuridine Incorporation, Koji Hamasaki, Richard A. Long, Farooq Azam Oct 2012

Individual Cell Growth Rates Of Marine Bacteria, Measured By Bromodeoxyuridine Incorporation, Koji Hamasaki, Richard A. Long, Farooq Azam

Richard A. Long

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 …


Coupling Between Bacterioplankton Species Composition, Population Dynamics, And Organic Matter Degradation, Jarone Pinhassi, Farooq Azam, Johanna Hemphälä, Richard A. Long, Josefina Martinez, Ulla Li Zweifel, Åke Hagström Oct 2012

Coupling Between Bacterioplankton Species Composition, Population Dynamics, And Organic Matter Degradation, Jarone Pinhassi, Farooq Azam, Johanna Hemphälä, Richard A. Long, Josefina Martinez, Ulla Li Zweifel, Åke Hagström

Richard A. Long

To study the effect of substrate addition on short term bacterial population dynamics and species composition in seawater mesocosms were maintained with water collected off Scripps Pier (La Jolla, California USA) Protein enrichment (BSA) triggered a dynamic response from the microbial food web, whereas enrichment with starch had no effect. In the protein enriched mesocosm the number of both nucleoid-containing cells and metabolically active cells increased by 3.0 X 105 cells ml-1 from Day 1 to Day 4 In the same time period the density of a set of 31 phylogenetically different bacteria (α- and g-Proteobactena as well as Flexibacter-Cytophaga-Bacteroides) …


Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman Sep 2012

Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman

Solomon Buckman Dr.

The Early Paleozoic Lachlan Fold Belt of eastern Australia is widely regarded as an ancient convergent plate margin beneath which paleo-Pacific (Panthalassic) oceanic lithosphere was continuously subducted. It is cited as the type example of a retreating accretionary orogeny. However, sandstone compositions, the sedimentological nature and timing of chert accumulation and overall stratigraphic architecture are not necessarily consistent with this model. We suggest an alternative explanation for growth of Gondwanan continental margin. Oceanic lithosphere outboard of the passive Gondwana continental margin was subducted beneath an extensive intra-oceanic island arc that now crops out as an allochthonous element (Macquarie arc) within …


Effects Of Husbandry Parameters On The Life-History Traits Of The Apple Snail, Marisa Cornuarietis: Effects Of Temperature, Photoperiod, And Population Density, John Aufderheide, Ryan Warbritton, Nadine Pounds, Sharon File-Emperador, Charles Staples, Norbert Caspers, Valery E. Forbes Mar 2012

Effects Of Husbandry Parameters On The Life-History Traits Of The Apple Snail, Marisa Cornuarietis: Effects Of Temperature, Photoperiod, And Population Density, John Aufderheide, Ryan Warbritton, Nadine Pounds, Sharon File-Emperador, Charles Staples, Norbert Caspers, Valery E. Forbes

Valery E Forbes

These experiments are part of a larger study designed to investigate the influence of husbandry parameters on the life history of the apple snail, Marisa cornuarietis. The overall objective of the program is to identify suitable husbandry conditions for maintaining multigeneration populations of this species in the laboratory for use in ecotoxicological testing. In this article, we focus on the effects of photoperiod, temperature, and population density on adult fecundity and juvenile growth. Increasing photoperiod from 12 to 16 h of light per day had no effect on adult fecundity or egg hatching and relatively minor effects on juvenile growth …