A quadratic programming method was developed for the statistical
analysis of gas chromatographic data. The method was applied to
three types of flavor extracts, peppermint, hops and brewed tea. The
brewed tea data had to be abandoned because of the singularity of its
coveriance matrix. In all cases tried the...
A method for the determination of selenium in biological
materials by gas-liquid chromatography has been developed and
successfully applied to kidney, heart, liver, and muscle tissue. The
initial digestion of animal tissue was accomplished in a mixture of
nitric and perchloric acids (3:1) until "water whiteness'' of solution
was achieved....
The study of diffusion coefficients of n-alkanes and other organic compounds in silicones is undertaken by gas-liquid chromatography. About 0. 3% of stationary phase is coated on glass bead support so that the only significant source of peak spreading is due to slow liquid phase mass transfer. Diffusion coefficients are...
Diffusion of short chain n-alkanes was found to be faster in the
polydimethylsilicone elastomer SE-30 than in the polydimethylsilicone
oil SF-96-2000. The opposite was true for the longer chain n-alkanes
suggesting that choice of stationary phase for gas chromatography
would depend on the chain length of sample components. The dependence...
Gas-solid chromatography often has asymmetrical elution
peaks. This is attributed to nonlinear isotherms, multi-energy
adsorption sites, and slow processes. This study utilized a stopflow
gas chromatograph with various NaOH and NaCl modified
aluminas as adsorbents and methane as adsorbate to determine the
influence of surface area and pore volume distribution...
A classification of stationary liquids by infrared spectroscopy to evaluate the polarity was made using the solvent effect technique. The infrared C-Cl absorption frequency shift was measured for solutions of 1-chlorohexane dissolved in each stationary phase. These frequency shifts were correlated to the relative retention times of 1-octene/n-octane, trans-2-octene/n-octane and...
The study of the obstructive factor by Hawkes (11) showed a relation
between the obstructive factor and velocity using a continuous
method. Later, Bowers and Hawkes (12) developed a similar method with
some improvements in the apparatus and found out that the obstructive
factor was not flow dependent. This study...
A specially designed gas chromatograph with both TCD and FID has
been tested for the measurement of the diffusion coefficients of methane and propane in helium. Knox's arrested elution technique(⁴) was used and yielded a value of 0.6431 cm²/sec averaged with the value
obtained by Yang and Hawkes(⁷). Values of...
Ultraviolet spectroscopy and dispersive solubility parameters
correlated to the ratios of retention times have proven valuable in
classification of gas chromatography stationary phases by the donor-acceptor
properties. Iodine was directly dissolved into stationary
phases and the absorption frequency shift of complexes was correlated
with the carbon tetrachloride/chloroform retention ratio on...
Significant figures have been a nebulous area in the physical sciences. The results of a literature survey, and of a questionaire distributed among the Chemistry Department faculty at Oregon State University, revealed widely differing interpretations regarding the proper role of significant figures. The present study has a two-fold nature. First...
Our experiments aimed to investigate responses of the marine cyanobacteria Prochlorococcus and Synechococcus to toxic arsenic species, such as arsenate, and to understand cellular mechanisms that contribute to arsenic tolerance. We used two strains of Prochlorococcus, a high-light adapted MED4 and low-light adapted MIT9313, both axenic, for cultivation experiments. For...
Oligotrophic bacteria are adapted to low nutrient concentrations. As most of the ocean is oligotrophic (low in nutrients), oligotrophic bacteria thrive in the ocean and make up the majority of planktonic cells. Because of this, oligotrophs are crucial to oceanic nutrient cycles. However, marine oligotrophic bacteria are dwarfed by their...
Oceanic carbon cycling plays a major role in determining global atmospheric CO₂. A better understanding of dissolved organic matter and its constituents in the water column and how it affects marine carbon cycling is sought after. This study successfully measured osmolytes, low molecular zwitterionic compounds derived from amino acids, in...
Historically, the difficulty of obtaining pure cultures of abundant marine
microbial plankton has an obstacle to reconstructing the underlying
mechanisms of biogeochemistry in the ocean. While a number of dominant
marine species from the ocean surface have been cultured, the dominant
microbial plankton of the dark ocean proved far more...
Over 100 monthly bacterioplankton DNA samples, from each of the surface and 200 m depths at the Bermuda Atlantic Time-series Study (BATS) site, were analyzed for community assembly processes. Correlation networks, filtered for potential autocorrelation artifacts, were constructed for each depth. Network characteristics for the two depths were remarkably similar...
SAR11 Alphaproteobacteria are the most abundant aerobic chemoheterotrophs in ocean surface waters. Previous studies have indicated SAR11 cells play an important role in marine carbon cycling and consume up to half of some common dissolved organic compounds, such as amino acids. During sequencing of the first SAR11 genome, genes for...
Members of the SAR11 clade of heterotrophic α-proteobacteria are ubiquitous and abundant in the world's oceans where they are thought to play a pivotal role in the global carbon cycle. The first SAR11 bacterium cultivated in vitro, 'Candidatus Pelagibacter ubique' HTCC1062 (Ca. P. ubique), was isolated by dilution into sterile...
SAR11 is a clade of marine bacteria that are the most abundant heterotrophs in ocean surface water. They play a significant role in marine carbon cycling. Although many culturing experiments have been done on SAR11, there was no research that focused on verifying the observations about inhibition of SAR11 growth...
The objective of this project was to use ribosomal RNA genes, cloned
from natural populations of Sargasso Sea bacterioplankton, as markers for
picoplankton diversity. It is widely recognised that a majority of
microorganisms have yet to be cultivated, and therefore much of extant
microbial diversity remains unknown (50). The method...
Symbiotic relationships of bacteria with higher organisms are
commonly observed in nature; however, the functional role of these
relationships is only rarely understood. This is particularly evident in
epibiotic bacterial associations in the marine environment where the bacteria
are often a diverse ensemble of microorganisms, thus complicating the
identification of...
The phylogenetic diversity of two continental shelf picoplankton
communities was examined by analyzing SSU (16S) ribosomal RNA (rRNA)
genes amplified from environmental DNA with bacterial-specific primers and
the polymerase chain reaction (PCR). Picoplankton populations collected from
the pycnocline (10 m) over the eastern continental shelf of the United States
near...
Research on natural environments, over the last decade, is replete with microbial diversity studies that used culture-independent approaches. The cloning and sequencing of the 16S rRNA genes has been the driving force in the expansion of awareness about the great diversity of previously undiscovered microorganisms. Well-known uncultured groups of microorganisms...
A new high-throughput culturing (HTC) method using a low nutrient
heterotrophic medium (LNHM) has led to the isolation of many novel strains of
oligotrophic bacteria from marine ecosystems. Four strains belonging to a single
dade, HTCC2151, HTCC218OT, HTCC2178T and HTCC2188T, were isolated
from the coast of Oregon by the HTC...
The sea as a dynamic conducting medium interacts continually
with the earth' s magnetic field. The physical principles underlying
this interaction are reviewed. These results are applied to the
particular problem of towed electrodes at the sea surface. Data
using this method are then shown to be sensitive to stability...
Continental shelves located along eastern boundary currents occupy relatively small volumes of the world’s oceans, yet are responsible for a large proportion of global primary production. The Oregon coast is among these ecosystems. Recent analyses of dissolved oxygen at shallow depths in the water column has suggested increasing episodes of...
Microorganisms play key roles in ocean biogeochemistry. However, several
predominant groups of uncultured bacterioplankton thought to contribute to
important biogeochemical processes in the oceans are known primarily from gene
cloning studies. Although these studies have greatly expanded our view of
microbial diversity in the oceans, they are not quantitative and...
The most abundant clone found in ribosomal RNA clone libraries obtained from the world's oceans belongs to the SAR11 phylogenetic group of environmental marine bacteria. Imaging and counting SAR11 bacterial cells in situ has been an important research objective for the past decade. This objective has been especially challenging due...
Batch cultures of Candidatus Pelagibacter ubique were grown under iron-, organosulfur-, and nitrogen-limiting conditions to understand how this ubiquitous marine bacterium responds to and interacts with environments where growth is limited by the availability of these nutrients. Global gene expression was monitored using microarrays and quantitative mass spectrometry to observe...
The effects of five data processing methods on the accuracy of
geostrophic computations are analyzed using hydrographic data collected
from a set of 24 hour triangular stations off the Oregon coast.
Sources of error are assessed by comparison with an available in
situ Salinity/Temperature/Depth record (STD) trace at a control...
In the early 1980's the first evidence of biological alteration of basalt glass (sideromelane) was published. Since that time additional evidence, including DNA staining, isotopic abundance and chemical mapping, has come to light suggesting that this unique alteration of glass can be attributed to microbial activity. Microbial alteration textures have...
A series of experiments was performed to determine the feasibility of genomic
DNA-based methods for ecological and physiological studies of dominant bacteria from
complex natural systems. Two approaches, bacterial chromosomal painting (BCP) and
environmental genomics (EG), were evaluated for the potential to identify and enumerate
specific bacterial groups in situ...
Microbial activity within elevated CO2 and oxygen depleted environments changes with
density driven stratification overturn in the seasonally anoxic region of Devil’s Hole,
Bermuda. The temperature gradient developed during the summer months creates a
natural laboratory to study bacterial and virus population density and microbial
community dynamics in the anoxic...
Microbial activity within elevated CO2 and oxygen depleted environments changes with
density driven stratification overturn in the seasonally anoxic region of Devil’s Hole,
Bermuda. The temperature gradient developed during the summer months creates a
natural laboratory to study bacterial and virus population density and microbial
community dynamics in the anoxic...
To identify factors limiting 'Candidatus Pelagibacter ubique' maximum cell density and growth rate in pure culture on seawater, the genome sequence of 'Cand. P. ubique' was analyzed, culturing experiments with organic and inorganic nutrient additions were made, and radiotracer uptake experiments were performed. The genome was sequenced, custom data mining...
Candidatus Pelagibacter ubique is the first cultured representative of the SAR11 clade, a clade that is found throughout the oceans and accounts for approximately 25% of all bacterial cells [1]. It has a streamlined genome that is the smallest of any known free-living organism. In this study the complete genome...
High-throughput culturing (HTC) consisting of extinction culturing in autoclaved seawater has led to the isolation and characterization of many novel strains of oligotrophic marine bacteria. Strain HTCC 2207 was isolated from the Oregon coast by the HTC method. Phylogenetic analysis based on 16S rRNA gene sequence showed that this strain...
The lack of availability of a single, complete paper on the
analysis of a digital data acquisition system for in situ oceanographic
measurements brought about the present work. In order to compile
an accurate technical paper on such a complex system, it was necessary
to design, construct, and calibrate a...
Proteins are the metabolic machines of the cell and as such, the study of proteins could illuminate the dominant biological activities that are occurring within cells and reveal how an organism interacts with its environment. Here, we used proteomic techniques to study the abundant marine bacterium SAR11 both as an...
Oceanic crust covers nearly 70% of the Earth's surface, of which, the upper,
sediment layer is estimated to harbor substantial microbial biomass. Marine crust;
however, extends several kilometers beyond this surficial layer, and includes the
basalt and gabbro layers. In particular, the basalt layer has high permeabilities which
allows for...