bluuebunny/crossref_metadata_2025 huggingface dataset:
VOLATILE ORGANIC COMPOUNDS IN GROUND WATER FROM RURAL PRIVATE WELLS, 1986 TO 19991
Authors: Moran Michael J. , Lapham Wayne W. , Rowe Barbara L. , Zogorski John S.
Published: June 2007

ABSTRACT: The U.S. Geological Survey (USGS) collected or compiled data on volatile organic compounds (VOCs) in samples of untreated ground water from 1,926 rural private wells during 1986 to 1999. At least one VOC was detected in 12 percent of samples from rural private wells. Individual VOCs were not commonly detected with the seven most frequently detected compounds found in only 1 to 5 percent of samples at or above a concentration of 0.2 microgram per liter (μg/l). An assessment level of 0.2 μg/l was selected so that comparisons of detection frequencies between VOCs could be made. The seven most frequently detected VOCs were: trichloromethane, methyl tert‐butyl ether, tetrachloroethene, dichlorodifluoromethane, methylbenzene, 1,1,1‐trichloroethane, and 1,2‐dibromo‐3‐chloropropane. Solvents and trihalomethanes were the most frequently detected VOC groups in private wells. The distributions of detections of gasoline oxygenates and fumigants seemed to be related to the use patterns of compounds in these groups. Mixtures were a common mode of occurrence of VOCs with one‐quarter of all samples with detections including two or more VOCs. The concentrations of most detected VOCs were relatively small and only 1.4 percent of samples had one or more VOC concentrations that exceeded a federally established drinking water standard or health criterion.
TEMPORAL CHANGES IN THE YADKIN RIVER FLOW VERSUS SUSPENDED SEDIMENT CONCENTRATION RELATIONSHIP1
Authors: Lamon E. Conrad , Qian Song S. , Richter Daniel D.
Published: June 2007

ABSTRACT:Dynamiclinear models (DLM) and seasonal trend decomposition (STL) using local regression, or LOESS, were used to analyze the 50‐year time series of suspended sediment concentrations for the Yadkin River, measured at the U.S. Geological Survey station at Yadkin College, North Carolina. A DLM with constant trend, seasonality, and a log10streamflow regressor provided the best model to predict monthly mean log10suspended sediment concentrations, based on the forecast log likelihood. Using DLM, there was evidence (odds approximately 69:1) that the log10streamflow versus log10suspended sediment concentration relationship has changed, with an approximate 20 percent increase in the log10streamflow coefficient over the period 1981 to 1996. However, sediment concentrations in the Yadkin River have decreased during the decade of the 1990s, which has been accompanied by a concomitant increase in streamflow variability. Although STL has been shown to be a versatile trend analysis technique, DLM is shown to be more suitable for discovery and inference of structural changes (trends) in the model coefficient describing the relationship between flow and sediment concentration.
MODELING TO EVALUATE MACROPHYTE INDUCED IMPACTS TO DISSOLVED OXYGEN IN A TAILWATER RESERVOIR1
Authors: Stansbury John , Admiraal David M.
Published: June 2007

ABSTRACT: Effects of aquatic macrophytes are not considered in most standard water quality models. This study used field measurements and water quality models to help determine the effects of aquatic macrophytes on dissolved oxygen (DO) concentrations in a shallow tailwater reservoir. Installation of a hydropower plant and macrophytes (primarily Potamogeton and Chara) in a large shallow portion of the lake are possible causes of reduced DO levels in the tailwater reservoir. A water quality model (WASP5) was used to quantify the various DO sources and sinks and to evaluate the effects of the hydropower operations on DO levels in the lake. It was found that the macrophytes in Lake Ogallala had a significant effect on the DO levels in the lake. At an average macrophyte density of about 6,360 g/m2 (wet weight) in 2000, the DO fluctuated daily from about 3 mg/l to about 12 mg/l. At an average macrophyte density of about 2,120 g/m2 (wet weight) in 2002, the DO fluctuated from about 5 mg/l to about 9 mg/l daily. The model predicted that the DO would remain near 5 mg/l without macrophytes. The photo‐synthetic and respiration rates developed in the model (4.4 mg/g‐hr and 1.4 mg/g‐hr, respectively) agree well with literature values.
MODELING THE IMPACTS OF WATER LEVEL CHANGES ON A GREAT LAKES COMMUNITY1
Authors: Schwartz Ryan C. , Deadman Peter J. , Scott Daniel J. , Mortsch Linda D.
Published: June 2007

ABSTRACT: Recent research that couples climate change scenarios based on general circulation models (GCM) with Great Lakes hydrologic models has indicated that average water levels are projected to decline in the future. This paper outlines a methodology to assess the potential impact of declining water levels on Great Lakes waterfront communities, using the Lake Huron shoreline at Goderich, Ontario, as an example. The methodology utilizes a geographic information system (GIS) to combine topographic and bathymetric datasets. A digital elevation surface is used to model projected shoreline change for 2050 using water level scenarios. An arbitrary scenario, based on a 1 m decline from February 2001 lake levels, is also modeled. By creating a series of shoreline scenarios, a range of impact and cost scenarios are generated for the Goderich Harbor and adjacent marinas. Additional harbor and marina dredging could cost as much as CDN $7.6 million. Lake freighters may experience a 30 percent loss in vessel capacity. The methodology is used to provide initial estimates of the potential impacts of climate change that can be readily updated as more robust climate change scenarios become available and is adaptable for use in other Great Lakes coastal communities.
NUTRIENT MASS BALANCE AND TRENDS, MOBILE RIVER BASIN, ALABAMA, GEORGIA, AND MISSISSIPPI1
Authors: Harned Douglas A. , Atkins J. Brian , Harvill John S.
Published: June 2007

ABSTRACT: A nutrient mass balance — accounting for nutrient inputs from atmospheric deposition, fertilizer, crop nitrogen fixation, and point source effluents; and nutrient outputs, including crop harvest and storage — was calculated for 18 subbasins in the Mobile River Basin, and trends (1970 to 1997) were evaluated as part of the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program. Agricultural nonpoint nitrogen and phosphorus sources and urban nonpoint nitrogen sources are the most important factors associated with nutrients in this system. More than 30 percent of nitrogen yield in two basins and phosphorus yield in eight basins can be attributed to urban point source nutrient inputs. The total nitrogen yield (1.3 tons per square mile per year) for the Tombigbee River, which drains a greater percentage of agricultural (row crop) land use, was larger than the total nitrogen yield (0.99 tons per square mile per year) for the Alabama River. Decreasing trends of total nitrogen concentrations in the Tombigbee and Alabama Rivers indicate that a reduction occurred from 1975 to 1997 in the nitrogen contributions to Mobile Bay from the Mobile River. Nitrogen concentrations also decreased (1980 to 1995) in the Black Warrior River, one of the major tributaries to the Tombigbee River. Total phosphorus concentrations increased from 1970 to 1996 at three urban influenced sites on the Etowah River in Georgia. Multiple regression analysis indicates a distinct association between water quality in the streams of the Mobile River drainage basin and agricultural activities in the basin.
EFFECT OF WATERSHED SUBDIVISION ON SWAT FLOW, SEDIMENT, AND NUTRIENT PREDICTIONS1
Authors: Jha Manoj , Gassman Philip W. , Secchi Silvia , Gu Roy , Arnold Jeff
Published: June 2007

ABSTRACT: The size, scale, and number of subwatersheds can affect a watershed modeling process and subsequent results. The objective of this study was to determine the appropriate level of subwatershed division for simulating flow, sediment, and nutrients over 30 years for four Iowa watersheds ranging in size from 2,000 to 18,000 km2 with the Soil and Water Assessment Tool (SWAT) model. The results of the analysis indicated that variation in the total number of subwatersheds had very little effect on streamflow. However, the opposite result was found for sediment, nitrate, and inorganic P; the optimal threshold subwatershed sizes, relative to the total drainage area for each watershed, required to adequately predict these three indicators were found to be around 3, 2, and 5 percent, respectively. Decreasing the size of the subwatersheds below these threshold levels does not significantly affect the predicted levels of these environmental indicators. These threshold subwatershed sizes can be used to optimize input data preparation requirements for SWAT analyses of other watersheds, especially those within a similar size range. The fact that different thresholds emerged for the different indicators also indicates the need for SWAT users to assess which indicators should have the highest priority in their analyses.
ADAPTING EXISTING MODELS TO EXAMINE EFFECTS OF AGRICULTURAL CONSERVATION PROGRAMS ON STREAM HABITAT QUALITY1
Authors: Shields F. Douglas. , Langendoen Eddy J. , Doyle Martin W.
Published: June 2007

Annual expenditures by the federal government in the United States for agricultural conservation programs increased about 80 percent with passage of the 2002 Farm Bill. However, environmental benefits of these programs have not been quantified. A national project is under way to estimate the effect of conservation practices on environmental resources. The watershed models intended for use in that project are focused on water quantity and quality and have minimal habitat assessment capability. Major impairments to aquatic ecosystems in many watersheds consist of physical habitat degradation, not water quality, suggesting that current models for this national initiative do not address one of the most significant aspects of aquatic ecosystem degradation. Currently used models contain some components relevant to aquatic habitat, and this paper describes specific components that should be added to allow rudimentary stream habitat quality assessments. At least six types of variables could be examined for ecological impact: land use, streamflow, water temperature, streambed material type, large woody debris, and hydraulic conditions at base flow. All of these variables are influenced by the presence, location, and quality of buffers. Generation of stream corridor ecological or habitat quality indices might contribute to assessments of the success or failure of conservation programs. Additional research is needed to refine procedures for combining specific measures of stream habitat into ecologically meaningful indices.
POST‐HARVEST RIPARIAN BUFFER RESPONSE: IMPLICATIONS FOR WOOD RECRUITMENT MODELING AND BUFFER DESIGN1
Authors: Liquori Michael K.
Published: June 2007

Despite the importance of riparian buffers in providing aquatic functions to forested streams, few studies have sought to capture key differences in ecological and geomorphic processes between buffered sites and forested conditions. This study examines post‐harvest buffer conditions from 20 randomly selected harvest sites within a managed tree farm in the Cascade Mountains of western Washington. Post‐harvest wind derived treefall rates in buffers up to three years post‐harvest averaged 268 trees/km/year, 26 times greater than competition‐induced mortality rate estimates. Treefall rates and stem breakage were strongly tied to tree species and relatively unaffected by stream direction. Observed treefall direction is strongly biased toward the channel, irrespective of channel or buffer orientation. Fall direction bias can deliver significantly more wood recruitment relative to randomly directed treefall, suggesting that models that utilize the random fall assumption will significantly underpredict recruitment. A simple estimate of post‐harvest wood recruitment from buffers can be obtained from species specific treefall and breakage rates, combined with bias corrected recruitment probability as a function of source distance from the channel. Post‐harvest wind effects may reduce the standing density of trees enough to significantly reduce or eliminate competition mortality and thus indirectly alter bank erosion rates, resulting in substantially different wood recruitment dynamics from buffers as compared to unmanaged forests.
EVAPOTRANSPIRATION DYNAMICS AT AN ECOHYDROLOGICAL RESTORATION SITE: AN ENERGY BALANCE AND REMOTE SENSING APPROACH1
Authors: Oberg Jason W. , Melesss Assefa M.
Published: June 2007

ABSTRACT: Little work is reported where spatial methods are employed to monitor evapotranspiration (ET) changes as a result of vegetation and wetland restoration. A remote sensing approach with the Surface Energy Balance Algorithm for Land (SEBAL) for estimating ET at The Nature Conservancy's Glacial Ridge prairie‐wetland restoration site in northwestern Minnesota is presented. The calibrated 24‐hour ET from SEBAL was estimated with an average error of prediction of −4.3 percent. Monthly, interseasonal, and seasonal ET for the period of June to September (2000 to 2003) from three adjacent land‐uses: a hydrologic control preserved wetland; a treated or restored site; and a nontreated or impacted wetland, were used in the study. Results from comparing ET behavior to the preserve suggest restoration efforts have affected monthly and seasonal ET within the treated site. Spatial average standard deviations of the seasonal ET within the preserve, treated, and nontreated sites give 47.3, 75.7, and 109.9 mm, respectively, suggesting hydrologic stabilization within the treated site. Monthly and interseasonal comparisons show similar behavior to that of the seasonal data, where monthly correlations suggest increasing agreement within the treated site, approaching those within the preserve.
USING STREAM BIOASSESSMENT PROTOCOLS TO MONITOR IMPACTS OF A CONFINED SWINE OPERATION1
Authors: Jack Jeffrey , Kelley Randall H. , Stiles David
Published: June 2007

ABSTRACT: The processing of waste from confined animal feeding operations (CAFOs) presents a major environmental challenge. Treatment of waste and subsequent land application is a common best management practice (BMP) for these operations in Kentucky, USA, but there are few data assessing the effect of runoff from such operations on aquatic communities. The authors sampled a stream bordering a CAFO with a land application program to determine if runoff from the fertilized fields was adversely affecting stream communities. Water chemistry, periphyton, and macroinvertebrate samples from riffle habitats downstream of the CAFO were compared to samples collected from an upstream site and a control stream in 1999 and 2000. Riffle communities downstream of the fertilized fields had higher chlorophyll a levels than other sites, but there were no significant differences in macroinvertebrate numbers or in biometrics such as taxa richness among the sites. The BMP in place at this site may be effective in reducing this CAFO's impact on the stream; however, similar assessments at other CAFO sites should be done to assess their impacts. Functional measures such as nutrient retention and litter decomposition of streams impacted by CAFOs should also be investigated to ensure that these operations are not adversely affecting stream communities.
DISSOLVED HEAVY METALS IN SHALLOW GROUND WATER IN A SOUTHEASTERN MICHIGAN URBAN WATERSHED1
Authors: Murray Kent S. , Rogers Daniel T. , Kaufman Martin M.
Published: June 2007

ABSTRACT: The occurrence of dissolved heavy metal concentrations in shallow ground water were measured at 126 sites within an urban watershed in southeastern Michigan. A total of 1,140 samples were collected from the first saturated zone, and the mean concentrations of 11 heavy metals (arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and zinc) were obtained and compared to their corresponding mean concentrations within surface soil. The results suggest that former and current land use processes have resulted in significant adverse impacts on the study region. Levels of Cr 20 to 30 times the maximum contaminant level (MCL) have been detected in the ground water beneath industrial sites. In addition, Cd and Pb have been found at levels exceeding their MCLs where surface soils are clay‐rich, and in sandy soils at more than 10 times their MCLs. The high levels of Cr in ground water strongly suggest that the chromium is in a hexavalent form, and this likelihood is supported by current studies. Given the hydraulic connection between the watershed's surface waters and the Great Lakes, these findings raise significant ecological and public health concerns.
EVALUATION OF THE APPLICABILITY OF THE SWAT MODEL FOR COASTAL WATERSHEDS IN SOUTHEASTERN LOUISIANA1
Authors: Wu Kangsheng , Xu Y. Jun
Published: June 2007

ABSTRACT: The Soil and Water Assessment Tool (SWAT) has been used for hydrologic analyses at various watershed scales. However, little is known about the model's performance in coastal watersheds. In this study SWAT was evaluated for its applicability in three Louisiana coastal watersheds: the Amite, Tickfaw, and Tangipahoa River watersheds. The model was calibrated with daily discharge from 1976 to 1977 and validated from 1979 to 1999 for the Amite and Tangipahoa and with daily discharge from 1979 to 1989 for the Tickfaw. Deviation of mean discharge and the Nash‐Sutcliffe model efficiency were used to evaluate model behavior. The study found that Manning's roughness coefficient for the main channel, SCS curve number, and soil evaporation compensation factor were the most sensitive parameters for these coastal watersheds. The Manning's roughness coefficient showed the greatest effect on the response time of surface runoff, suggesting the critical role of channel routing in hydrologic modeling for lowland watersheds. The SWAT model demonstrated an excellent performance, with Nash‐Sutcliffe efficiencies of 0.935, 0.940, and 0.960 for calibrations of the Amite, Tickfaw, and Tangipahoa watersheds, respectively, and of 0.851, 0.811, and 0.867 for validations. The modeling results demonstrate that SWAT is capable of simulating hydrologic processes for medium scale to large scale coastal lowland watersheds in Louisiana.
A Study to Understand Perceptual Discrepancies Using Visual Illusions and Data Envelopment Analysis (DEA)
Authors: Şahin Aslı , Bøe Maria , Terpenny Janis , Bøhn Jan Helge
Published: June 2007

There are often discrepancies in how a product is perceived in the different display media employed in typical product development processes. Product developers in many cases rely on different display media for design realizations. This study investigates if and how perceptual discrepancies change across different media and design groups. An experiment was designed and conducted at Virginia Tech to compare the perceptual differences of a simplified model of a car across three types of representation media: industrial design sketches, Computer aided design (CAD) models, and physical prototypes. The geometry of the car window was varied to simulate two visual illusions; architrave and irradiation. Two groups (industrial designers and engineers) with varying levels of experience (students and professionals) were studied. The experimental results were analyzed by applying a two-step data envelopment analysis (DEA) approach to identify the trends of how the shape perception varied within and across the subject groups. This study and its findings are particularly important in several ways. First, the DEA approach provides an objective comparison of groups when differences in the participants’ evaluation skills and experience levels should be explicitly taken into account, important to understanding student learning and effectiveness of practitioners. Our study has shown that designers’ perceptual evaluation strategies change significantly across the groups. Findings of this study can be used for understanding perceptual discrepancies across media and groups in product design and development and could help to inform new approaches to design education research.
Creativity and the Use of CAD Tools: Lessons for Engineering Design Education From Industry
Authors: Robertson Brett F. , Walther Joachim , Radcliffe David F.
Published: June 2007

This paper presents an exploratory study that transfers lessons on creativity and the use of CAD tools from an industry case study to engineering design education. The participant-observation case study found four influences of the use of CAD on creativity of designers. The one positive and three negative effects were confirmed by a theoretical investigation of creative problem solving in engineering design. Similar effects were also seen in the context of engineering education in a study that examined the broad, holistic aspects of student learning outside the paradigm of targeted instruction. The paper is based on the notion that students' creative design capabilities are formed through the interaction of CAD instruction and other factors from the wider educational environment. A competence formation matrix based on the concept of Accidental Competence formation was developed to analyze this combination of the effects of CAD usage with other educational factors. The analysis shows that these combinations have long-term positive and negative effects on the development of creative abilities in engineering students.
Probabilistic Modeling Approach for Evaluating the Compliance of Ready-To-Eat Foods with New European Union Safety Criteria for
Listeria monocytogenes
Authors: Koutsoumanis Konstantinos , Angelidis Apostolos S.
Published: June 2007

Among the new microbiological criteria that have been incorporated in EU Regulation 2073/2005, of particular interest are those concerning
Listeria monocytogenes
in ready-to eat (RTE) foods, because for certain food categories, they no longer require zero tolerance but rather specify a maximum allowable concentration of 100 CFU/g or ml. This study presents a probabilistic modeling approach for evaluating the compliance of RTE sliced meat products with the new safety criteria for
L. monocytogenes
. The approach was based on the combined use of (i) growth/no growth boundary models, (ii) kinetic growth models, (iii) product characteristics data (pH, a
w
, shelf life) collected from 160 meat products from the Hellenic retail market, and (iv) storage temperature data recorded from 50 retail stores in Greece. This study shows that probabilistic analysis of the above components using Monte Carlo simulation, which takes into account the variability of factors affecting microbial growth, can lead to a realistic estimation of the behavior of
L. monocytogenes
throughout the food supply chain, and the quantitative output generated can be further used by food managers as a decision-making tool regarding the design or modification of a product's formulation or its “use-by” date in order to ensure its compliance with the new safety criteria. The study also argues that compliance of RTE foods with the new safety criteria should not be considered a parameter with a discrete and binary outcome because it depends on factors such as product characteristics, storage temperature, and initial contamination level, which display considerable variability even among different packages of the same RTE product. Rather, compliance should be expressed and therefore regulated in a more probabilistic fashion.
Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs
Authors: Van der Meulen Roel , Scheirlinck Ilse , Van Schoor Ann , Huys Geert , Vancanneyt Marc , Vandamme Peter , De Vuyst Luc
Published: June 2007

Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination of various chromatographic methods including liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The establishment of a stable microbial ecosystem occurred through a three-phase evolution within a week, as revealed by both microbiological and metabolite analyses. Strains of
Lactobacillus plantarum
,
Lactobacillus fermentum
,
Lactobacillus rossiae
,
Lactobacillus brevis
, and
Lactobacillus paraplantarum
were dominating some of the sourdough ecosystems. Although the heterofermentative
L. fermentum
was dominating one of the wheat sourdoughs, all other sourdoughs were dominated by a combination of obligate and facultative heterofermentative taxa. Strains of homofermentative species were not retrieved in the stable sourdough ecosystems. Concentrations of sugar and amino acid metabolites hardly changed during the last days of fermentation. Besides lactic acid, ethanol, and mannitol, the production of succinic acid, erythritol, and various amino acid metabolites, such as phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid, was shown during fermentation. Physiologically, they contributed to the equilibration of the redox balance. The biphasic approach of the present study allowed us to map some of the interactions taking place during sourdough fermentation and helped us to understand the fine-tuned metabolism of lactic acid bacteria, which allows them to dominate a food ecosystem.
Putative Porin of
Bradyrhizobium
sp. (
Lupinus
) Bacteroids Induced by Glyphosate
Authors: de María Nuria , Guevara Ángeles , Serra M. Teresa , García-Luque Isabel , González-Sama Alfonso , de Lacoba Mario García , de Felipe M. Rosario , Fernández-Pascual Mercedes
Published: June 2007

Application of glyphosate (
N
-[phosphonomethyl] glycine) to
Bradyrhizobium
sp. (
Lupinus
)-nodulated lupin plants caused modifications in the protein pattern of bacteroids. The most significant change was the presence of a 44-kDa polypeptide in bacteroids from plants treated with the higher doses of glyphosate employed (5 and 10 mM). The polypeptide has been characterized by the amino acid sequencing of its N terminus and the isolation and nucleic acid sequencing of its encoding gene. It is putatively encoded by a single gene, and the protein has been identified as a putative porin. Protein modeling revealed the existence of several domains sharing similarity to different porins, such as a transmembrane beta-barrel. The protein has been designated BLpp, for
Bradyrhizobium
sp. (
Lupinus
) putative porin, and would be the first porin described in
Bradyrhizobium
sp. (
Lupinus
). In addition, a putative conserved domain of porins has been identified which consists of 87 amino acids, located in the BLpp sequence 30 amino acids downstream of the N-terminal region. In bacteroids, mRNA of the BLpp gene shows a basal constitutive expression that increases under glyphosate treatment, and the expression of the gene is seemingly regulated at the transcriptional level. By contrast, in free-living bacteria glyphosate treatment leads to an inhibition of BLpp mRNA accumulation, indicating a different effect of glyphosate on BLpp gene expression in bacteroids and free-living bacteria. The possible role of BLpp in a metabolite interchange between
Bradyrhizobium
and lupin is discussed.
Biophysical Controls on Community Succession in Stream Biofilms
Authors: Besemer Katharina , Singer Gabriel , Limberger Romana , Chlup Ann-Kathrin , Hochedlinger Gerald , Hödl Iris , Baranyi Christian , Battin Tom J.
Published: June 2007

Biofilm formation is controlled by an array of coupled physical, chemical, and biotic processes. Despite the ecological relevance of microbial biofilms, their community formation and succession remain poorly understood. We investigated the effect of flow velocity, as the major physical force in stream ecosystems, on biofilm community succession (as continuous shifts in community composition) in microcosms under laminar, intermediate, and turbulent flow. Flow clearly shaped the development of biofilm architecture and community composition, as revealed by microscopic investigation, denaturing gradient gel electrophoresis (DGGE) analysis, and sequencing. While biofilm growth patterns were undirected under laminar flow, they were clearly directed into ridges and conspicuous streamers under turbulent flow. A total of 51 biofilm DGGE bands were detected; the average number ranged from 13 to 16. Successional trajectories diverged from an initial community that was common in all flow treatments and increasingly converged as biofilms matured. We suggest that this developmental pattern was primarily driven by algae, which, as “ecosystem engineers,” modulate their microenvironment to create similar architectures and flow conditions in all treatments and thereby reduce the physical effect of flow on biofilms. Our results thus suggest a shift from a predominantly physical control to coupled biophysical controls on bacterial community succession in stream biofilms.
Sinorhizobium meliloti
Fur-Like (Mur) Protein Binds a Fur Box-Like Sequence Present in the
mntA
Promoter in a Manganese-Responsive Manner
Authors: Platero Raúl , de Lorenzo Víctor , Garat Beatriz , Fabiano Elena
Published: June 2007

In
Sinorhizobium meliloti
, the Mur
Sm
protein, a homologue of the ferric uptake regulator (Fur), mediates manganese-dependent regulation of the MntABCD manganese uptake system. In this study, we analyzed Mur
Sm
binding to the promoter region of the
S. meliloti mntA
gene. We demonstrated that Mur
Sm
protein binds with high affinity to the promoter region of
mntA
gene in a manganese-responsive manner. Moreover, the results presented here indicate that two monomers, or one dimer, of Mur
Sm
binds the DNA. The binding region was identified by DNase I footprinting analysis and covers a region of about 30 bp long that contains a palindromic sequence. The Mur
Sm
binding site, present in the
mntA
promoter region, is similar to a Fur box; however, manganese-activated Mur
Sm
binds a canonical Fur box with very low affinity. Furthermore, the data obtained indicate that Mur
Sm
responds to physiological concentrations of manganese.
Evaluation of Two Library-Independent Microbial Source Tracking Methods To Identify Sources of Fecal Contamination in French Estuaries
Authors: Gourmelon Michèle , Caprais Marie Paule , Ségura Raphaël , Le Mennec Cécile , Lozach Solen , Piriou Jean Yves , Rincé Alain
Published: June 2007

In order to identify the origin of the fecal contamination observed in French estuaries, two library-independent microbial source tracking (MST) methods were selected: (i)
Bacteroidales
host-specific 16S rRNA gene markers and (ii) F-specific RNA bacteriophage genotyping. The specificity of the
Bacteroidales
markers was evaluated on human and animal (bovine, pig, sheep, and bird) feces. Two human-specific markers (HF183 and HF134), one ruminant-specific marker (CF193′), and one pig-specific marker (PF163) showed a high level of specificity (>90%). However, the data suggest that the proposed ruminant-specific CF128 marker would be better described as an animal marker, as it was observed in all bovine and sheep feces and 96% of pig feces. F RNA bacteriophages were detected in only 21% of individual fecal samples tested, in 60% of pig slurries, but in all sewage samples. Most detected F RNA bacteriophages were from genotypes II and III in sewage samples and from genotypes I and IV in bovine, pig, and bird feces and from pig slurries. Both MST methods were applied to 28 water samples collected from three watersheds at different times. Classification of water samples as subject to human, animal, or mixed fecal contamination was more frequent when using
Bacteroidales
markers (82.1% of water samples) than by bacteriophage genotyping (50%). The ability to classify a water sample increased with increasing
Escherichia coli
or enterococcus concentration. For the samples that could be classified by bacteriophage genotyping, 78% agreed with the classification obtained from
Bacteroidales
markers.
Sugar Nucleotide Pools of
Trypanosoma brucei
,
Trypanosoma cruzi
, and
Leishmania major
Authors: Turnock Daniel C. , Ferguson Michael A. J.
Published: June 2007

The cell surface glycoconjugates of trypanosomatid parasites are intimately involved in parasite survival, infectivity, and virulence in their insect vectors and mammalian hosts. Although there is a considerable body of work describing their structure, biosynthesis, and function, little is known about the sugar nucleotide pools that fuel their biosynthesis. In order to identify and quantify parasite sugar nucleotides, we developed an analytical method based on liquid chromatography-electrospray ionization-tandem mass spectrometry using multiple reaction monitoring. This method was applied to the bloodstream and procyclic forms of
Trypanosoma brucei
, the epimastigote form of
T. cruzi
, and the promastigote form of
Leishmania major
. Five sugar nucleotides, GDP-α-
d
-mannose, UDP-α-
d
-
N
-acetylglucosamine, UDP-α-
d
-glucose, UDP-α-galactopyranose, and GDP-β-
l
-fucose, were common to all three species; one, UDP-α-
d
-galactofuranose, was common to
T. cruzi
and
L. major
; three, UDP-β-
l
-rhamnopyranose, UDP-α-
d
-xylose, and UDP-α-
d
-glucuronic acid, were found only in
T. cruzi
; and one, GDP-α-
d
-arabinopyranose, was found only in
L. major
. The estimated demands for each monosaccharide suggest that sugar nucleotide pools are turned over at very different rates, from seconds to hours. The sugar nucleotide survey, together with a review of the literature, was used to define the routes to these important metabolites and to annotate relevant genes in the trypanosomatid genomes.
ESAT-6 fromMycobacterium tuberculosisDissociates from Its Putative Chaperone CFP-10 under Acidic Conditions and Exhibits Membrane-Lysing Activity
Authors: de Jonge Marien I. , Pehau-Arnaudet Gérard , Fretz Marjan M. , Romain Felix , Bottai Daria , Brodin Priscille , Honoré Nadine , Marchal Gilles , Jiskoot Wim , England Patrick , Cole Stewart T. , Brosch Roland
Published: June 2007

The 6-kDa early secreted antigenic target ESAT-6 and the 10-kDa culture filtrate protein CFP-10 ofMycobacterium tuberculosisare secreted by the ESX-1 system into the host cell and thereby contribute to pathogenicity. Although different studies performed at the organismal and cellular levels have helped to explain ESX-1-associated phenomena, not much is known about how ESAT-6 and CFP-10 contribute to pathogenesis at the molecular level. In this study we describe the interaction of both proteins with lipid bilayers, using biologically relevant liposomal preparations containing dimyristoylphosphatidylcholine (DMPC), dimyristoylphosphatidylglycerol, and cholesterol. Using floatation gradient centrifugation, we demonstrate that ESAT-6 showed strong association with liposomes, and in particular with preparations containing DMPC and cholesterol, whereas the interaction of CFP-10 with membranes appeared to be weaker and less specific. Most importantly, binding to the biomembranes no longer occurred when the proteins were present as a 1:1 ESAT-6·CFP-10 complex. However, lowering of the pH resulted in dissociation of the protein complex and subsequent protein-liposome interaction. Finally, cryoelectron microscopy revealed that ESAT-6 destabilized and lysed liposomes, whereas CFP-10 did not. In conclusion, we propose that one of the main features of ESAT-6 in the infection process ofM. tuberculosisis the interaction with biomembranes that occurs after dissociation from its putative chaperone CFP-10 under acidic conditions typically encountered in the phagosome.
Mutations in the Tryptophan Operon Allow PurF-Independent Thiamine Synthesis by Altering Flux In Vivo
Authors: Ramos Itzel , Vivas E. I. , Downs D. M.
Published: June 2007

Phosphoribosyl amine (PRA) is an intermediate in purine biosynthesis and also required for thiamine biosynthesis in
Salmonella enterica
. PRA is normally synthesized by phosphoribosyl pyrophosphate amidotransferase, a high-turnover enzyme of the purine biosynthetic pathway encoded by
purF
. However, PurF-independent PRA synthesis has been observed in strains having different genetic backgrounds and growing under diverse conditions. Genetic analysis has shown that the anthranilate synthase-phosphoribosyltransferase (AS-PRT) enzyme complex, involved in the synthesis of tryptophan, can play a role in the synthesis of PRA. This work describes the in vitro synthesis of PRA in the presence of the purified components of the AS-PRT complex. Results from in vitro assays and in vivo studies indicate that the cellular accumulation of phosphoribosyl anthranilate can result in nonenzymatic PRA formation sufficient for thiamine synthesis. These studies have uncovered a mechanism used by cells to redistribute metabolites to ensure thiamine synthesis and may define a general paradigm of metabolic robustness.
A CASE OF CEREBRAL MUCORMYCOSIS DIAGNOSED IN LIFE, WITH EVENTUAL RECOVERY
Authors: Muresan Augustin
Published: June 2007

A case of mucormycosis localized in the brain is reported in a subject aged 18 years who was not suffering from diabetes. As the patient displayed symptoms of cerebral compression he was operated upon and a cystic formation was excised.

Microscopic examination disclosed the presence of hyphae, displaying the characteristics of mucor, in chronic granulation tissue. The mycelia had a tendency to develop in the vessels and to invade them, and a structure very similar to a sporangium could be observed. Some of the mycelia had undergone dystrophic calcification.

The patient has been kept under medical supervision for two and a half years since the operation and appears to have completely recovered.
THE BACTERIOLOGY OF URINARY INFECTIONS IN PARAPLEGIA
Authors: Scott T. G.
Published: June 2007

Two hundred and forty-seven strains of micro-organisms were isolated from the urinary tract of 121 patients with neurological complaints leading to paraplegia. The commonest infecting organism wasE. coliand the commonest type of Proteus wasP. mirabilis. Infections with more than one type of organism were present in 37% of urine specimens, and in such cases the incidence ofE. coliwas lower and that ofStrep. faecalishigher than the incidences in infections with only one type of organism.

No evidence was found which might suggest that the various bacterial species encountered showed either an undue degree of synergism or of mutual antagonism.

Coliforms were the commonest primary pathogens, butStrep. faecalisand Proteus species occurred with the same frequency as the coliforms when they were considered as secondary invaders.

The variance between the incidences of various species as reported by different workers is considered to be due to the different illnesses and conditions which predispose to urinary tract infection. It appears that infections in the urinary tract by more than one type of organism at a time occur more frequently in those patients with the more chronic predisposing causes. (Some disparity in findings may also result from the differing taxonomic methods employed by different workers, but this is probably insufficiently important to account for the largest differences.)
THROMBOTIC THROMBOCYTOPENIC PURPURA
Authors: Bornstein B. , Boss J. H. , Casper J. , Behar M.
Published: June 2007

A case of thrombotic thrombocytopenic purpura in a 50-year-old woman is described. Almost the whole course of the disease, lasting 18 months, was characterized by a bizarre neurological disorder, and the haematological manifestations first appeared at a late stage.

In many organs a vast number of arterioles and capillaries contained plugs of a fibrinoid material, and fibrinoid was subendothelially accumulated in a few of these vessels; but, in addition, mediumsized arteries of the myocardium were also obstructed by this same material. There were also verrucal endocardiosis of the mitral valve and slight thickening of the glomerular basement membranes. The striking diffusion of a pathological substance through damaged cerebral vessel walls into the nervous tissue seems to be a significant contribution to the understanding of the pathogenesis of the vascular pathology of thrombotic thrombocytopenic purpura.
A SIMPLE METHOD FOR THE DETERMINATION OF SERUM HAPTOGLOBINS
Authors: Owen J. A. , Better F. C. , Hoban J.
Published: June 2007

Changes in the serum haptoglobin level have been reported in certain forms of anaemia (Allison and ap Rees, 1957; Allison, 1958; Nosslin and Nyman, 1958; Nyman, Gydell, and Nosslin, 1959), in hepatobiliary disease (Owen, Mackay, and Got, 1959) and in various inflammatory and chronic diseases (Jayle and Boussier, 1955; Allison and Blumberg, 1958). A simple colorimetric procedure for the determination of serum haptoglobins is presented. It is based on the peroxidase activity of haptoglobin-methaemoglobin complexes.
THE COLICINE TYPING OF COLIFORM BACILLI IN THE STUDY OF CROSS-INFECTION IN UROLOGY
Authors: Linton K. B.
Published: June 2007

Three hundred and fourteen strains of coliform bacilli (79Klebsiellaand 235E. coli), mostly isolated from urine, were investigated for their production of, or sensitivity to, certain colicines.

Only oneKlebsiellastrain showed colicine activity, but in 204 of theE. colistrains colicine production or sensitivity was demonstrated.

Colicine typing was of considerable value in epidemiological investigations of post-operative urinary infections due toE. coli.
ANGIOSARCOMA OF THE HEART
Authors: Harris Hilda R.
Published: June 2007

The clinical features and pathological details of a primary cardiac angiosarcoma are described.

The significance of the various clinical manifestations of primary cardiac tumours is discussed.

The incidence, the histological diagnosis, and the histogenesis of primary cardiac angiosarcoma are considered.
ANTIBODY OF BLOOD-GROUP SPECIFICITY IN SIMPLE (“COLD”) HAEMOLYTIC ANAEMIAS
Authors: Weiner W. , Shinton N. K. , Gray I. R.
Published: June 2007

Two cases of “cold” (simple) haemolytic anaemia are described. The serological investigation showed conclusively that the sera of both patients contained an anti-I antibody and that their cells were I positive. The antibody found is thus a true auto-antibody. This is in keeping with the findings obtained previously in the “warm” (hyperimmune) type of haemolytic anaemia.
SERUM TRANSAMINASES AND ISOCITRIC DEHYDROGENASE IN KWASHIORKOR
Authors: Baron D. N.
Published: June 2007

Serum glutamic oxalacetic transaminase (G-OT), glutamic-pyruvic transaminase (G-PT), and isocitric dehydrogenase (ICD) have been estimated in six groups of subjects, namely, normal British adults, normal Nigerian adults, undernourished Nigerian adults and children, Nigerian children with florid protein malnutrition (kwashiorkor), and cases of protein malnutrition after treatment.

The normal range in Nigerian adults was apparently slightly lower than in European adults.

A marked increase in serum enzyme activity was found in florid malnutrition, and a slight rise in undernutrition. In all cases serum G-PT showed lesser changes than G-OT and ICD.

The causes of these abnormalities are discussed. The increased serum enzyme activity is thought to be derived primarily from the liver and possibly also from voluntary muscle. Estimation of serum enzymes is recommended in the investigation of protein malnutrition.
THE BUFFERED PERFORMIC-ACID-ALCIAN-BLUE-PERIODIC-ACID-SCHIFF METHOD FOR THE DIFFERENTIATION OF BASOPHILS IN THE HUMAN AND RAT PITUITARY
Authors: Swettenham K.
Published: June 2007

The difficulty of using a single method for staining rat and human pituitary was investigated by testing separately and in different combinations the effects of the various components in the performic-acid-alcian-blue(P.F.A.B.)-periodic-acid-Schiff(P.A.S.) method (Adams and Swettenham, 1958). In this way the possibility of inhibiting or enhancing by one procedure the staining effects of the other could be assessed. The profound influence of fixation on these staining methods was demonstrated by employing the same set of staining methods on tissues fixed in different ways.

The possibility that unbuffered performic acid might exert a considerable solvent action on certain proteins was considered to be related to the difficulty of applying the P.F.A.B.-P.A.S. method to the rat pituitary. Buffered performic acid has far less solvent action and the P.F.A.B.-P.A.S. method, modified by the replacement of buffered for unbuffered performic acid, proved to be successful in the demonstration of two types of basophil cells in both rat and man.
THE LATEX SLIDE TEST IN RHEUMATIC DISORDERS
Authors: Wilson J. V. , Morison R. A. H. , Wright V.
Published: June 2007

The latex slide test (L.S.T.) has been shown to be simple to perform and easy to read. It gives results comparable with the more complicated serological procedures used in the diagnosis of rheumatoid arthritis.

In 603 cases the L.S.T. and differential agglutination test gave a high degree of correlation. There were only four discrepancies between the two tests. The L.S.T. is the more practicable for routine laboratory use.

The L.S.T. has been correlated with the duration, activity, and extent of rheumatoid arthritis, and also with the erythrocyte sedimentation rate, haemoglobin level, and radiographic appearances. The various serological tests are tabulated.
SERUM HAPTOGLOBINS IN HAEMOLYTIC STATES
Authors: Owen J. A. , de Gruchy G. C. , Smith H.
Published: June 2007

Serum haptoglobin levels have been studied in patients with a number of haemolytic disorders.

In general, serum haptoglobins were low in patients with increased haemolysis. Values were reduced irrespective of whether haemolysis occurred intravascularly or extravascularly.

The reduction was related to the amount of haemoglobin destroyed per day.

Serum haptoglobins may be raised in certain neoplasms and infections and during adrenocortical steroid hormone therapy. A rise in haptoglobins due to one of these factors may mask a fall due to haemolysis. Thus a normal or raised serum haptoglobin does not necessarily exclude a haemolytic process.
Radiation sterilization
Authors: Darmady E. M. , Hughes K. E. A. , Burt Margaret M. , Freeman Barbara M. , Powell D. B.
Published: June 2007

The sterilization by radiation of disposable medical items has been investigated. Various vegetative and spore-bearing bacteria have been irradiated and results indicate that 2·5 Mrad can be recommended to give a high degree of sterility. Spores ofB. pumilus(E.601) showed such resistance that it might be a suitable test organism for determining the efficiency of a radiation treatment. A high standard of packaging must be demanded for pre-sterilized products.
Sterilization by gas ovens
Authors: Patrick E. A. K. , Wharton R. H. , Prentis K. , Signy A. G.
Published: June 2007

A forced convection gas-fired oven has been designed which will sterilize a very heavy load of syringes and instruments and containers. It is superior to a gas-fired, infrared, radiant-heated oven which was designed for sterilizing syringes.
Preserving the sterility of surgical dressings wrapped in paper and other materials
Authors: Alder V. G. , Alder F. I.
Published: June 2007

Materials for wrapping surgical dressings were studied by a method which measured the recontamination rate in packs stored for periods of up to several weeks. Of the materials tested a thick crêpe paper was better than calico and balloon cloth fabrics. Dressings wrapped in paper were not significantly contaminated after storage in dusty places for periods of up to three weeks. For added protection during handling and for convenience in transport and storage, paper packs may be sterilized and kept in paper-lined cartons. The shelf life in good storage conditions would be many weeks at least.