bluuebunny/crossref_metadata_2025 huggingface dataset:
INFLUENCE OF TWO WOODY RIPARIAN SPECIES ON CRITICAL CONDITIONS FOR STREAMBANK STABILITY: UPPER TRUCKEE RIVER, CALIFORNIA1
Authors: Simon Andrew , Pollen Natasha , Langendoen Eddy
Published: June 2007

Over the past 35 years, a trend of decreasing water clarity has been documented in Lake Tahoe, attributable in part to the delivery of fine grained sediment emanating from upland and channel erosion. A recent study showed that the Upper Truckee River is the single largest contributor of sediment to Lake Tahoe, with a large proportion of the sediment load emanating from streambanks. This study combines field data with numerical modeling to identify the critical conditions for bank stability along an unstable reach of the Upper Truckee River, California. Bank failures occur during winter and spring months, brought on by repeated basal melting of snow packs and rain‐on‐snow events. Field studies of young lodgepole pines and Lemmon's willow were used to quantify the mechanical, hydrologic, and net effects of riparian vegetation on streambank stability. Lemmon's willow provided an order of magnitude more root reinforcement (5.5 kPa) than the lodgepole pines (0.5 kPa); the hydrologic effects of the species varied spatially and temporally and generally were of a smaller magnitude than the mechanical effects. Overall, Lemmon's willow provided a significant increase in bank strength, reducing the frequency of bank failures and delivery of fine grained sediment to the study reach of the Upper Truckee River.
ECONOMIC ANALYSIS OF WETLAND RESTORATION ALONG THE ILLINOIS RIVER1
Authors: Prato Tony , Hey Donald
Published: June 2007

Creating and restoring wetland and riparian ecosystems between farms and adjacent streams and rivers in the Upper Mississippi River Basin would reduce nitrogen loads and hypoxia in the Gulf of Mexico and increase local environmental benefits. Economic efficiency and economic impacts of the Hennepin and Hopper Lakes Restoration Project in Illinois were evaluated. The project converted 999 ha of cropland to bottomland forest, backwater lakes, and flood‐plain wetland habitat. Project benefits were estimated by summing the economic values of wetlands estimated in other studies. Project costs were estimated by the loss in the gross value of agricultural production from the conversion of corn and soybean acreage to wetlands. Estimated annual net benefit of wetland restoration in the project area amounted to US$1,827 per ha of restored wetland or US$1.83 million for the project area, indicating that the project is economically efficient. Impacts of the project on the regional economy were estimated (using IMPLAN) in terms of changes in total output, household income, and employment. The project is estimated to increase total output by US$2,028,576, household income by US$1,379,676, and employment by 56 persons, indicating that it has positive net economic impacts on the regional economy.
INFLUENCE OF HERBIVORY ON REGROWTH OF RIPARIAN SHRUBS FOLLOWING A WILDLAND FIRE1
Authors: Dwire Kathleen A. , Ryan Sandra E. , Shirley Laura J. , Lytjen Danna , Otting Nick , Dixon Mark K.
Published: June 2007

Streamside vegetation frequently regenerates faster than upland vegetation following wildland fire and contributes to the recovery of riparian and stream ecosystems. Limited data are available, however, on the post‐fire growth of riparian species and the influence of herbivory on regeneration. To determine post‐fire regrowth of riparian vegetation, height, crown area, crown volume, and browse levels were measured for key riparian shrub species in streamside burned and unburned plots along second‐order streams in western Wyoming. Shrubs in the burned plots were subject to high levels of browse ‐ up to 84 percent of the leaders were browsed ‐ by native ungulates in 2002, the second post‐fire year (September 2001 to September 2002). In summer 2003, the burned watershed was also grazed by livestock, resulting in increased browse levels and decreased shrub heights for several species. In the third post‐fire year, September 2002 to September 2003, four of the six most common species showed no increase in crown area or crown volume, indicating that the combination of native ungulate and cattle browsing suppressed their growth. Potential impacts of grazing on post‐fire recovery of stream and riparian ecosystems are discussed.
EQUIVALENCE BETWEEN TOPMODEL AND THE NRCS CURVE NUMBER METHOD IN PREDICTING VARIABLE RUNOFF SOURCE AREAS1
Authors: Nachabe Mahmood H.
Published: June 2007

An equivalence is proposed between two rainfall‐runoff methods with a long history of use in the United States and Europe. In watersheds where variable source areas dominate runoff, the two methods can have comparable probability distribution functions of moisture deficit, and therefore predict similar saturated runoff source areas. A novel approach is introduced to determine the S parameter in the Natural Resources Conservation Service (NRCS) method. This approach constrains S by the physical soil and topography characteristics of the catchment and depth to water table. The NRCS curve number method is at the core of many rainfall‐runoff models in hydrology. As a simple lumped parameter method, it is often scrutinized because it is not obvious how to derive S from catchment hydromorphological characteristics. The novel approach provides a clear physical meaning for S, allowing better estimation of this parameter in humid shallow water table environments where the variable source area can be the dominant runoff mechanism.
EVALUATION OF NEXRAD STAGE III PRECIPITATION DATA OVER A SEMIARID REGION1
Authors: Xie Hongjie , Zhou Xiaobing , Hendrickx Jan M.H. , Vivoni Enrique R. , Guan Huade , Tian Yong Q. , Small Eric E.
Published: June 2007

This study examines NEXRAD Stage III product (hourly, cell size 4 km by 4 km) for its ability in estimating precipitation in central New Mexico, a semiarid area. A comparison between Stage III and a network of gauge precipitation estimates during 1995 to 2001 indicates that Stage III (1) overestimates the hourly conditional mean (CM) precipitation by 33 percent in the monsoon season and 55 percent in the nonmonsoon season; (2) overestimates the hourly CM precipitation for concurrent radar‐gauge pairs (nonzero value) by 13 percent in the monsoon season and 6 percent in the nonmonsoon season; (3) overestimates the seasonal precipitation accumulation by 11 to 88 percent in monsoon season and underestimates by 18 to 89 percent in the nonmonsoon season; and (4) either overestimates annual precipitation accumulation up to 28.2 percent or underestimates it up to 11.9 percent. A truncation of 57 to 72 percent of the total rainfall hours is observed in the Stage III data in the nonmonsoon season, which may be the main cause for both the underestimation of the radar rainfall accumulation and the lower conditional probability of radar rainfall detection in the nonmonsoon season. The study results indicate that the truncation caused loss of small rainfall amounts (events) is not effectively corrected by the real‐time rain gauge calibration that can adjust the rainfall rates but cannot recover the truncated small rainfall events. However, the truncation error in the monsoon season may be suppressed due to the larger rainfall rate and/or combined effect of overestimates by bright band and hail contaminations, virga, advection, etc. In general, improvement in NEXRAD performance since the monsoon season in 1998 is observed, which is consistent with the systematic improvement in the NEXRAD network.
EFFECTS OF INITIAL ABSTRACTION AND URBANIZATION ON ESTIMATED RUNOFF USING CN TECHNOLOGY1
Authors: Lim Kyoung Jae , Engel Bernard A. , Muthukrishnan Suresh , Harbor Jon
Published: June 2007

ABSTRACT: Few studies have been conducted to explore the effects of initial abstraction on estimated direct runoff despite the widespread use of the curve number (CN) method in many hydrologic models to estimate direct runoff. In this study, use of a 5 percent ratio of initial abstraction (Ia) to storage (S) to estimate daily direct runoff with modified CN values for a 5 percent Ia/S value was investigated using the Long‐Term Hydrologic Impact Assessment (L‐THIA) geographic information system (GIS). In addition, the effects on estimated runoff of altering the hydrologic soil group due to urbanization were investigated. The L‐THIA model was applied to the Indiana Little Eagle Creek watershed with 5 percent and 20 percent Ia/S values, considering hydrologic soil group alteration due to urbanization. The results indicate that uses of a 5 percent la/S and modified CN values and Hydrologic Soil Group D for urbanized areas in model runs can improve long term direct runoff prediction.
SPATIAL VARIATION OF NUTRIENT BALANCE IN THE TRUCKEE RIVER, CALIFORNIA‐NEVADA1
Authors: Green Mark B. , Fritsen Christian H.
Published: June 2007

ABSTRACT: Because the Truckee River connects two lakes along the Eastern Sierra Nevada Mountains with different limiting nutrients, this research addresses whether the nitrogen:phosphorus (N:P) balance of the river ecosystem changes longitudinally. Historical (1990 to 2000) total nitro‐gen:total phosphorus (TN:TP) ratios in river water exhibited the expected gradient from high N:P ratios upstream to low N:P ratios downstream, with the major gradient of the N:P balance occurring within the transition between montane and high desert terrain. During 2001, the river contained anomalously low total nitrogen concentrations in the far upper reaches and dissolved inorganic nitrogen concentrations in the lower reaches, resulting in a less apparent longitudinal gradient of N:P ratios. Measurements of periphyton growth and physiology (nutrient bioassays and ectoenzyme activities) and stoichiometry during the summer of 2001 also exhibited a complex picture of the spatial variation of N:P balance that was not entirely consistent with a strong N:P gradient. However, the compendium of the indicators did support the overall picture of an overarching longitudinal gradient from high to low N:P ratios. The results suggest that periphyton management efforts in the Truckee River should consider the overall spatial gradient as well as the small‐scale dynamics of the stream ecosystem structure.
ADEQUACY OF SELECTED EVAPOTRANSPIRATION APPROXIMATIONS FOR HYDROLOGIC SIMULATION1
Authors: Sumner David M.
Published: June 2007

ABSTRACT: Evapotranspiration (ET) approximations, usually based on computed potential ET (PET) and diverse PET‐to‐ET conceptualizations, are routinely used in hydrologic analyses. This study presents an approach to incorporate measured (actual) ET data, increasingly available using micrometeorological methods, to define the adequacy of ET approximations for hydrologic simulation. The approach is demonstrated at a site where eddy correlation‐measured ET values were available. A baseline hydrologic model incorporating measured ET values was used to evaluate the sensitivity of simulated water levels, subsurface recharge, and surface runoff to error in four ET approximations. An annually invariant pattern of mean monthly vegetation coefficients was shown to be most effective, despite the substantial year‐to‐year variation in measured vegetation coefficients. The temporal variability of available water (precipitation minus ET) at the humid, subtropical site was largely controlled by the relatively high temporal variability of precipitation, benefiting the effectiveness of coarse ET approximations, a result that is likely to prevail at other humid sites.
COMPILATION OF MEASURED NUTRIENT LOAD DATA FOR AGRICULTURAL LAND USES IN THE UNITED STATES1
Authors: Harmel Daren , Potter Steve , Casebolt Pamela , Reckhow Ken , Green Colleen , Haney Rick
Published: June 2007

ABSTRACT: Measured field scale data are increasingly used to guide policy and management decisions based on comparative pollutant load information from various land management alternatives. The primary objective of this study was to compile measured annual nitrogen (N) and phosphorus (P) load data representing field scale transport from agricultural land uses. This effort expanded previous work that established an initial nutrient export coefficient dataset. Only measured annual N and P load data published in scientific peer‐reviewed studies were included in the present compilation. Additional criteria for inclusion were: spatial scale (field scale or farm scale, minimum 0.009 ha); land use (homogeneous, either cultivated agriculture or pasture/rangeland/hay); natural rainfall (not rainfall simulation); and temporal scale (minimum one year). Annual N and P load data were obtained from 40 publications, resulting in a 163‐record database with more than 1,100 watershed years of data. Basic descriptive statistics in relation to N and P loads were tabulated for tillage management, conservation practices, fertilizer application, soil texture, watershed size, and land use (crop type). The resulting Measured Annual Nutrient loads from A Circumlittoral Environments (MANAGE) database provides readily accessible, easily queried watershed characteristic and nutrient load data and establishes a platform suitable for input of additional project specific data.
HYDROLOGIC BEHAVIOR OF VEGETATED ROOFS1
Authors: Carter Timothy L. , Rasmussen Todd C.
Published: June 2007

ABSTRACT: Control of stormwater runoff from impervious surfaces is an important national goal because of disruptions to downstream ecosystems, water users, and property owners caused by increased flows and degraded quality. One method for reducing stormwater is the use of vegetated (green) roofs, which efficiently detain and retain stormwater when compared to conventional (black) roofs. A paired green roof‐black roof test plot was constructed at the University of Georgia and monitored between November 2003 and November 2004 for the green roof's effectiveness in reducing stormwater flows. Stormwater mitigation performance was monitored for 31 precipitation events, which ranged in depth from 0.28 to 8.43 cm. Green roof precipitation retention decreased with precipitation depth; ranging from just under 90 percent for small storms (< 2.54 cm) to slightly less than 50 percent for larger storms (> 7.62 cm). Runoff from the green roof was delayed; average runoff lag times increased from 17.0 minutes for the black roof to 34.9 minutes for the green roof, an average increase of 17.9 minutes. Precipitation and runoff data were used to estimate the green roof curve number, CN = 86. This information can be used in hydrologic models for developing stormwater mitigation programs.
ARSENIC CONSUMPTION AND HEALTH RISK PERCEPTIONS IN A RURAL WESTERN U.S. AREA1
Authors: Walker Mark , Shaw W. Douglass , Benson Marnee
Published: June 2007

ABSTRACT: Churchill County, Nevada, has approximately 23,000 residents, among whom an estimated 13,500 relied on private wells for water supply in 2002. This study examined exposure to arsenic in water supplies among residents with private domestic wells and factors related to householder choice to consume tap water. It compared opinions and concerns about water quality with consumption habits and observed concentrations from tap water samples. The results from 351 households indicated that a majority (75 percent) of respondents consumed tap water and that a minority (38 percent) applied treatment. Approximately 66 percent of those who consumed tap water were exposed to concentrations of arsenic that exceeded 10 ppb. Water consumption was related to application of treatment. Among 98 respondents who were not at all concerned about the health effects of aqueous arsenic, 59 (60 percent) reported consuming tap water with concentrations of arsenic exceeding 10 ppb. Conversely, among 86 respondents who were highly concerned about arsenic, 33 (37 percent) consumed tap water with concentrations of arsenic exceeding 10 ppb. Results from a national sampling effort showed that 620 of 5,304 private wells sampled (11.7 percent) had arsenic concentrations above 10 ppb. The paradox of awareness of arsenic in water supplies coupled with consumption of aqueous arsenic in concentrations greater than 10 ppb may be common in other parts of the nation. Enhanced educational efforts, especially related to tap water sampling and explanations of efficacy of available treatment, may be useful means of reducing exposure through private water supplies.
Effects of Industrial Experience and Coursework During Sophomore and Junior Years on Student Learning of Engineering Design
Authors: Bailey Reid
Published: June 2007

While prior work indicates that seniors near the end of their capstone design course know more about design than first-year students, it is unclear where this knowledge is gained. We study two possible sources of seniors’ greater design knowledge: coursework during sophomore and junior years and industrial experience. The design process knowledge of seniors at the beginning of their capstone class was assessed and information about their industrial experience obtained. These data were compared to assessment data of first-year students at the end of an introduction to engineering design course. The results indicate that industrial experience greatly increases students’ recognition that documentation needs to occur throughout the design process. Seniors with industrial experience, however, are less aware that idea generation is an important part of design and are less able to allot time to different design activities than first-year students at the end of a hands-on introduction to engineering design course. For the remaining four aspects of design process knowledge assessed—namely, identifying the requirements for a project at the project’s outset, making decisions with a systematic process based on analysis, building and testing prototypes and final designs, and the overall layout of design including iteration—no differences are found between seniors with industrial experience and first-year students at the end of an introduction to engineering design course. One explanation for why industrial experience does not impact student’s design process knowledge positively in more areas than documentation is that students on internships only experience a small portion of a design process. Due to this “snapshot” experience, either (1) students are not able to learn a significant amount about the bigger picture design concepts or (2) students each learn about different aspects of design but, as a population, do not show any significant increase in design process knowledge. The one activity that all interns will experience is the necessity to document their work. Furthermore, seniors without industrial experience scored no differently than first-year students on any single aspect of design process knowledge measured. This indicates that analysis-heavy sophomore and junior classes do not impact design process knowledge.
Enhancing the Quality Function Deployment Conceptual Design Tool
Authors: Leary Martin , Burvill Colin
Published: June 2007

The quality function deployment (QFD) conceptual design tool has been of significant benefit to customer satisfaction, while reducing the associated design time and cost. Observation of novice designers in tertiary engineering design courses identified a range of impediments to the robust transfer of QFD capabilities to the novice designers. These impediments appear to limit the perceived merit of QFD in novice designers and stymie its subsequent practical application. Given the improved design outcomes associated with QFD, a series of enhancements has been developed to overcome these impediments and assist the robust transfer of QFD capabilities to novice designers. The traditional QFD tool does not engage with customer requirements that constrain the feasibility of a design solution. This limitation restricts the applicability of QFD as an overarching design reference because an additional repository is required to document design constraints and may result in confusion in novice designers and flawed design outcomes if design constraints are used. A novel differential assessment method has been developed to overcome this limitation by enabling the inclusion of design constraints. The outcomes of this paper contribute to design education by facilitating the robust transfer of QFD capabilities and providing novel enhancements that expand the useful outcomes associated with QFD.
Evidence of Temporal Postdischarge Decontamination of Bacteria by Gliding Electric Discharges: Application to
Hafnia alvei
Authors: Kamgang-Youbi Georges , Herry Jean-Marie , Bellon-Fontaine Marie-Noëlle , Brisset Jean-Louis , Doubla Avaly , Naïtali Murielle
Published: June 2007

This study aimed to characterize the bacterium-destroying properties of a gliding arc plasma device during electric discharges and also under temporal postdischarge conditions (i.e., when the discharge was switched off). This phenomenon was reported for the first time in the literature in the case of the plasma destruction of microorganisms. When cells of a model bacterium,
Hafnia alvei
, were exposed to electric discharges, followed or not followed by temporal postdischarges, the survival curves exhibited a shoulder and then log-linear decay. These destruction kinetics were modeled using GinaFiT, a freeware tool to assess microbial survival curves, and adjustment parameters were determined. The efficiency of postdischarge treatments was clearly affected by the discharge time (
t
*); both the shoulder length and the inactivation rate
k
max
were linearly modified as a function of
t
*. Nevertheless, all conditions tested (
t
* ranging from 2 to 5 min) made it possible to achieve an abatement of at least 7 decimal logarithm units. Postdischarge treatment was also efficient against bacteria not subjected to direct discharge, and the disinfecting properties of “plasma-activated water” were dependent on the treatment time for the solution. Water treated with plasma for 2 min achieved a 3.7-decimal-logarithm-unit reduction in 20 min after application to cells, and abatement greater than 7 decimal logarithm units resulted from the same contact time with water activated with plasma for 10 min. These disinfecting properties were maintained during storage of activated water for 30 min. After that, they declined as the storage time increased.
Impact of Three Ampicillin Dosage Regimens on Selection of Ampicillin Resistance in
Enterobacteriaceae
and Excretion of
bla
TEM
Genes in Swine Feces
Authors: Bibbal D. , Dupouy V. , Ferré J. P. , Toutain P. L. , Fayet O. , Prère M. F. , Bousquet-Mélou A.
Published: June 2007

The aim of this study was to assess the impact of three ampicillin dosage regimens on ampicillin resistance among
Enterobacteriaceae
recovered from swine feces by use of phenotypic and genotypic approaches. Phenotypically, ampicillin resistance was determined from the percentage of resistant
Enterobacteriaceae
and MICs of
Escherichia coli
isolates. The pool of ampicillin resistance genes was also monitored by quantification of
bla
TEM
genes, which code for the most frequently produced β-lactamases in gram-negative bacteria, using a newly developed real-time PCR assay. Ampicillin was administered intramuscularly and orally to fed or fasted pigs for 7 days at 20 mg/kg of body weight. The average percentage of resistant
Enterobacteriaceae
before treatment was between 2.5% and 12%, and
bla
TEM
gene quantities were below 10
7
copies/g of feces. By days 4 and 7, the percentage of resistant
Enterobacteriaceae
exceeded 50% in all treated groups, with some highly resistant strains (MIC of >256 μg/ml). In the control group,
bla
TEM
gene quantities fluctuated between 10
4
and 10
6
copies/g of feces, whereas they fluctuated between 10
6
to 10
8
and 10
7
to 10
9
copies/g of feces for the intramuscular and oral routes, respectively. Whereas phenotypic evaluations did not discriminate among the three ampicillin dosage regimens,
bla
TEM
gene quantification was able to differentiate between the effects of two routes of ampicillin administration. Our results suggest that fecal
bla
TEM
gene quantification provides a sensitive tool to evaluate the impact of ampicillin administration on the selection of ampicillin resistance in the digestive microflora and its dissemination in the environment.
Degradation Pathway of Bisphenol A: DoesipsoSubstitution Apply to Phenols Containing a Quaternary α-Carbon Structure in theparaPosition?
Authors: Kolvenbach B. , Schlaich N. , Raoui Z. , Prell J. , Zühlke S. , Schäffer A. , Guengerich F. P. , Corvini P. F. X.
Published: June 2007

The degradation of bisphenol A and nonylphenol involves the unusual rearrangement of stable carbon-carbon bonds. Some nonylphenol isomers and bisphenol A possess a quaternary α-carbon atom as a common structural feature. The degradation of nonylphenol inSphingomonassp. strain TTNP3 occurs via a type IIipsosubstitution with the presence of a quaternary α-carbon as a prerequisite. We report here a new degradation pathway of bisphenol A. Consequent to the hydroxylation at position C-4, according to a type IIipsosubstitution mechanism, the C-C bond between the phenolic moiety and the isopropyl group of bisphenol A is broken. Besides the formation of hydroquinone and 4-(2-hydroxypropan-2-yl)phenol as the main metabolites, further compounds resulting from molecular rearrangements consistent with a carbocationic intermediate were identified. Assays with resting cells or cell extracts ofSphingomonassp. strain TTNP3 under an18O2atmosphere were performed. One atom of18O2was present in hydroquinone, resulting from the monooxygenation of bisphenol A and nonylphenol. The monooxygenase activity was dependent on both NADPH and flavin adenine dinucleotide. Various cytochrome P450 inhibitors had identical inhibition effects on the conversion of both xenobiotics. Using a mutant ofSphingomonassp. strain TTNP3, which is defective for growth on nonylphenol, we demonstrated that the reaction is catalyzed by the same enzymatic system. In conclusion, the degradation of bisphenol A and nonylphenol is initiated by the same monooxygenase, which may also lead toipsosubstitution in other xenobiotics containing phenol with a quaternary α-carbon.
Role of Type IV Pilins in Persistence of
Vibrio vulnificus
in
Crassostrea virginica
Oysters
Authors: Paranjpye Rohinee N. , Johnson Asta B. , Baxter Anne E. , Strom Mark S.
Published: June 2007

Vibrio vulnificus
is part of the natural estuarine microflora and accumulates in shellfish through filter feeding. It is responsible for the majority of seafood-associated fatalities in the United States mainly through consumption of raw oysters. Previously we have shown that a
V. vulnificus
mutant unable to express PilD, the type IV prepilin peptidase, does not express pili on the surface of the bacterium and is defective in adherence to human epithelial cells (R. N. Paranjpye, J. C. Lara, J. C. Pepe, C. M. Pepe, and M. S. Strom, Infect. Immun.
66:
5659-5668, 1998). A mutant unable to express one of the type IV pilins, PilA, is also defective in adherence to epithelial cells as well as biofilm formation on abiotic surfaces (R. N. Paranjpye and M. S. Strom, Infect. Immun. 73:1411-1422, 2005). In this study we report that the loss of PilD or PilA significantly reduces the ability of
V. vulnificus
to persist in
Crassostrea virginica
over a 66-h interval, strongly suggesting that pili expressed by this bacterium play a role in colonization or persistence in oysters.
Production of Lactic Acid from Cellobiose and Cellotriose by
Lactobacillus delbrueckii
Mutant Uc-3
Authors: Adsul Mukund , Khire Jayant , Bastawde Kulbhushan , Gokhale Digambar
Published: June 2007

Lactobacillus delbrueckii
mutant Uc-3 utilizes both cellobiose and cellotriose efficiently, converting it into L(+) lactic acid. The enzyme activities of cellobiose and cellotriose utilization were determined for cell extracts, whole cells, and disrupted cells. Aryl-β-glucosidase activity was detected only for whole cells and disrupted cells, suggesting that these activities are cell bound. The mutant produced 90 g/liter of lactic acid from 100 g/liter of cellobiose with 2.25 g/liter/h productivity.
EnP1, a Microsporidian Spore Wall Protein That Enables Spores To Adhere to and Infect Host Cells In Vitro
Authors: Southern Timothy R. , Jolly Carrie E. , Lester Melissa E. , Hayman J. Russell
Published: June 2007

Microsporidia are spore-forming fungal pathogens that require the intracellular environment of host cells for propagation. We have shown that spores of the genus
Encephalitozoon
adhere to host cell surface glycosaminoglycans (GAGs) in vitro and that this adherence serves to modulate the infection process. In this study, a spore wall protein (EnP1;
Encephalitozoon cuniculi
ECU01_0820) from
E. cuniculi
and
Encephalitozoon intestinalis
is found to interact with the host cell surface. Analysis of the amino acid sequence reveals multiple heparin-binding motifs, which are known to interact with extracellular matrices. Both recombinant EnP1 protein and purified EnP1 antibody inhibit spore adherence, resulting in decreased host cell infection. Furthermore, when the N-terminal heparin-binding motif is deleted by site-directed mutagenesis, inhibition of adherence is ablated. Our transmission immunoelectron microscopy reveals that EnP1 is embedded in the microsporidial endospore and exospore and is found in high abundance in the polar sac/anchoring disk region, an area from which the everting polar tube is released. Finally, by using a host cell binding assay, EnP1 is shown to bind host cell surfaces but not to those that lack surface GAGs. Collectively, these data show that given its expression in both the endospore and the exospore, EnP1 is a microsporidian cell wall protein that may function both in a structural capacity and in modulating in vitro host cell adherence and infection.
Unusually Low Levels of Genetic Variation among
Giardia lamblia
Isolates
Authors: Teodorovic Smilja , Braverman John M. , Elmendorf Heidi G.
Published: June 2007

Giardia lamblia
, an intestinal pathogen of mammals, including humans, is a significant cause of diarrheal disease around the world. Additionally, the parasite is found on a lineage which separated early from the main branch in eukaryotic evolution. The extent of genetic diversity among
G. lamblia
isolates is insufficiently understood, but this knowledge is a prerequisite to better understand the role of parasite variation in disease etiology and to examine the evolution of mechanisms of genetic exchange among eukaryotes. Intraisolate genetic variation in
G. lamblia
has never been estimated, and previous studies on interisolate genetic variation have included a limited sample of loci. Here we report a population genetics study of intra- and interisolate genetic diversity based on six coding and four noncoding regions from nine
G. lamblia
isolates. Our results indicate exceedingly low levels of genetic variation in two out of three
G. lamblia
groups that infect humans; this variation is sufficient to allow identification of isolate-specific markers. Low genetic diversity at both coding and noncoding regions, with an overall bias towards synonymous substitutions, was discovered. Surprisingly, we found a dichotomous haplotype structure in the third, more variable
G. lamblia
group, represented by a haplotype shared with one of the homogenous groups and an additional group-specific haplotype. We propose that the distinct patterns of genetic-variation distribution among lineages are a consequence of the presence of genetic exchange. More broadly, our findings have implications for the regulation of gene expression, as well as the mode of reproduction in the parasite.
Comparative Analysis of Alterations in Host Phenotype and Transcript Accumulation following Hypovirus and Mycoreovirus Infections of the Chestnut Blight Fungus
Cryphonectria parasitica
Authors: Deng Fuyou , Allen Todd D. , Hillman Bradley I. , Nuss Donald L.
Published: June 2007

Infection of the chestnut blight fungus,
Cryphonectria parasitica
, by hypovirus CHV1-EP713 or by reovirus MyRV1-Cp9B21 or MyRV2-CpC18 results in reduced fungal virulence (hypovirulence). However, additional phenotypic changes caused by the two groups of mycoviruses are quite different. We now report that the loss of female fertility and the resulting absence of virus transmission through sexual spores observed after hypovirus infection was not observed for reovirus-infected
C. parasitica
. Consistent with this result, expression of two genes involved in sexual reproduction, the pheromone precursor gene,
Mf2/1
, and the yeast
STE12
-like transcriptional factor gene,
cpst12
, was less reduced in reovirus-infected strains than in the hypovirus CHV1-EP713-infected strain. Analysis with a custom microarray cDNA chip containing expressed sequence tag clones representing approximately 2,200 unique
C. parasitica
genes identified 140 and 128 host genes that were responsive to MyRV1-Cp9B21 or MyRV2-CpC18 infection, respectively. Comparison of these virus-responsive genes revealed an overlap of 85 genes, even though the nucleotide sequence identity for the two reoviruses is less than 50%. Significantly, 84 of the 85 genes were altered in the same direction. Further comparison revealed that 51% and 48% of the MyRV1-Cp9B21- and MyRV2-CpC18-responsive genes were also responsive to CHV1-EP713 infection. Finally, similar to results reported for CHV1-EP713 infection, a high percentage (59% and 66%) of the reovirus-responsive genes were also differentially expressed following disruption of the cellular G-protein signal transduction pathway. These data support the hypothesis that hypovirus and reovirus infections perturb common and specific
C. parasitica
regulatory pathways to cause hypovirulence and distinct sets of phenotypic changes.
Molecular Characterization of Membrane-Associated Soluble Serine Palmitoyltransferases from
Sphingobacterium multivorum
and
Bdellovibrio stolpii
Authors: Ikushiro Hiroko , Islam Mohammad Mainul , Tojo Hiromasa , Hayashi Hideyuki
Published: June 2007

Serine palmitoyltransferase (SPT) is a key enzyme in sphingolipid biosynthesis and catalyzes the decarboxylative condensation of
l
-serine and palmitoyl coenzyme A (CoA) to form 3-ketodihydrosphingosine (KDS). Eukaryotic SPTs comprise tightly membrane-associated heterodimers belonging to the pyridoxal 5′-phosphate (PLP)-dependent α-oxamine synthase family.
Sphingomonas paucimobilis
, a sphingolipid-containing bacterium, contains an abundant water-soluble homodimeric SPT of the same family (H. Ikushiro et al., J. Biol. Chem. 276:18249-18256, 2001). This enzyme is suitable for the detailed mechanistic studies of SPT, although single crystals appropriate for high-resolution crystallography have not yet been obtained. We have now isolated three novel SPT genes from
Sphingobacterium multivorum
,
Sphingobacterium spiritivorum
, and
Bdellovibrio stolpii
, respectively. Each gene product exhibits an ∼30% sequence identity to both eukaryotic subunits, and the putative catalytic amino acid residues are conserved. All bacterial SPTs were successfully overproduced in
Escherichia coli
and purified as water-soluble active homodimers. The spectroscopic properties of the purified SPTs are characteristic of PLP-dependent enzymes. The KDS formation by the bacterial SPTs was confirmed by high-performance liquid chromatography/mass spectrometry. The
Sphingobacterium
SPTs obeyed normal steady-state ordered Bi-Bi kinetics, while the
Bdellovibrio
SPT underwent a remarkable substrate inhibition at palmitoyl CoA concentrations higher than 100 μM, as does the eukaryotic enzyme. Immunoelectron microscopy showed that unlike the cytosolic
Sphingomonas
SPT,
S. multivorum
and
Bdellovibrio
SPTs were bound to the inner membrane of cells as peripheral membrane proteins, indicating that these enzymes can be a prokaryotic model mimicking the membrane-associated eukaryotic SPT.
SpoIVB and CtpB Are Both Forespore Signals in the Activation of the Sporulation Transcription Factor σKinBacillus subtilis
Authors: Campo Nathalie , Rudner David Z.
Published: June 2007

The proteolytic activation of the mother cell transcription factor pro-σKis controlled by a signal transduction pathway during sporulation in the bacteriumBacillus subtilis. The pro-σKprocessing enzyme SpoIVFB, a membrane-embedded metalloprotease, is held inactive by two other integral membrane proteins, SpoIVFA and BofA, in the mother cell membrane that surrounds the forespore. Two signaling serine proteases, SpoIVB and CtpB, trigger pro-σKprocessing by cleaving the regulatory protein SpoIVFA. The SpoIVB signal is absolutely required to activate pro-σKprocessing and is derived from the forespore compartment. CtpB is necessary for the proper timing of σKactivation and was thought to be a mother cell signal. Here, we show that thectpBgene is expressed in both the mother cell and forespore compartments but that synthesis in the forespore under the control of σGis both necessary and sufficient for the proper timing of pro-σKprocessing. We further show that SpoIVB cleaves CtpB in vitro and in vivo but that this cleavage does not appear to be necessary for CtpB activation. Thus, both signaling proteins are made in the forespore and independently target the same regulatory protein.
Genomic Characterization of the Filamentous Integrative Bacteriophages φRSS1 and φRSM1, Which Infect
Ralstonia solanacearum
Authors: Kawasaki Takeru , Nagata Shoko , Fujiwara Akiko , Satsuma Hideki , Fujie Makoto , Usami Shoji , Yamada Takashi
Published: June 2007

The genomic DNA sequences were determined for two filamentous integrative bacteriophages, φRSS1 and φRSM1, of the phytopathogen
Ralstonia solanacearum
. The 6,662-base sequence of φRSS1 contained 11 open reading frames (ORFs). In the databases, this sequence showed high homology (95% identity) to the circular double-stranded DNA plasmid pJTPS1 (6,633 bp) isolated from a spontaneously occurring avirulent mutant of
R. solanacearum
. Two major differences between the two sequences were observed within φRSS1 ORF7, corresponding to pIII, a minor coat protein required for host adsorption, and at the φRSS1 intergenic (IG) region. The 9,004-base sequence of φRSM1 showed 12 ORFs located on the same strand (plus strand) and 2 ORFs on the opposite strand. Compared with Ff-type phages, two insertions are obvious in the φRSM1 replication module. Genomic DNA fragments containing the φRSM integration junctions were cloned and sequenced from φRSM lysogenic strain
R. solanacearum
MAFF211270. The
att
core sequence was identified as 5′-TGGCGGAGAGGGT-3′, corresponding to the 3′ end of the serine tRNA (UCG) gene. Interestingly, ORF14, located next to the
attP
site on the φRSM1 genome, showed high amino acid sequence homology with bacterial DNA recombinases and resolvases, different from XerCD recombinases.
attP
of φRSS1 is within a sequence element of the IG region.
THE DEVELOPMENT OF AN ACQUIRED HAEMOGLOBIN ABNORMALITY CAUSED BY THERMAL INJURY
Authors: Baar S.
Published: June 2007

Alkali denaturation of the haemoglobin derived from burned patients at various intervals from the time of the injury was investigated. A delayed denaturation curve was always found.

The involvement of the transfused cells was established by a differential agglutination technique.

Red cell populations were fractionated into two portions, one of which was probably enriched in younger cells. This portion was preferentially affected.

A starch gel technique yielded a “slow” and a “fast” fraction of haemoglobin with differing denaturation rates, even in normals. The “slow” fraction appeared to be increased quantitatively and qualitatively, if compared with normal blood.
STRESS ZONES IN FOETAL ARTERIES
Authors: Robertson J. H.
Published: June 2007

In a study of the peripheral arteries of foetuses it was found that focal areas of intimal thickening and of splitting of the internal elastica had developed, the thickening being similar to that found in the coronary arteries. Characteristically the thickenings were found in the mouths of branches and in those vessels subject to pulsation. It is believed that they are physiological in nature and a response of the vascular wall to the stresses produced by focal areas of impaired pulsation and not degenerative as formerly thought.

The evolution of these arterial cushions is traced from early foetal life; their most important constituent is bundles of medial longitudinal muscle. Both thickening and splitting of the internal elastica are brought about by a radial reorientation and migration of the muscle cells of the media.
INFECTION WITH DIFFERENT SPECIES OF LEPTOSPIRES IN HUSBAND AND WIFE
Authors: Pathy M. S.
Published: June 2007

Leptospirosis occurring in a husband and wife is described. Both were responsible for cleaning up the excreta of a recently acquired puppy. The wife developed leptospirosis canicola, and three months later the husband developed leptospirosis icterohaemorrhagica. Difficulty was experienced in ascertaining the infecting species of leptospire in the husband owing to the agglutination tests giving an equal rise and fall in titres for bothL. icterohaemorrhagiaeandL. canicola.The diagnosis was only confirmed after cross-absorption tests had been done.

The husband developed pulmonary complications on the nineteenth day. The radiological appearances of the chest are discussed, together with a brief review of the literature on the radiological manifestations of pulmonary lesions in Weil's disease.
ANTIFIBRINOLYTIC ACTIVITY IN NORMAL PREGNANCY
Authors: Biezenski J. J.
Published: June 2007

It is found that serum antifibrinolytic activity is inhibitory both to the spontaneous fibrinolytic activity and to the activity of streptokinase-activated plasminogen.

The titres of serum antiplasmin activity during gestation, labour, and the puerperium are all of the same order and do not differ from those in non-pregnant women. The marked decrease in the spontaneous fibrinolytic activity in late pregnancy and labour is therefore due to an actual reduction in the circulating active lytic enzyme and is not associated with a change in the antifibrinolytic activity.
SYPHILITIC PAROXYSMAL COLD HAEMOGLOBINURIA
Authors: Parish D. J. , Mitchell J. R. A.
Published: June 2007

A case of congenital syphilis which presented with paroxysmal cold haemoglobinuria is described.

The patient had aortic incompetence, and the significance of this finding is discussed.

The Coombs test was studied, and positive results appear to be due to interaction between antiglobulin serum and complement adsorbed on to the test cells, this adsorption being promoted by the cold antibodies.
MISLEADING SPUTUM CARTONS
Authors: Thomas C. G. A. , Gibbs F. J.
Published: June 2007

Waxed paper sputum cartons obtained from the manufacturers contained very few organisms. Similar cartons which had been stored in hospital wards were often contaminated with hospital dust. This contamination was sometimes sufficiently marked to be misleading. Coliform organisms are particularly liable to cause confusion.

Waxed cartons are useful for collecting sputum, but they must be properly stored.
RETICULO-ENDOTHELIAL SARCOMA ARISING IN THE NOSE AND PALATE (GRANULOMA GANGRENESCENS)
Authors: Walton E. W.
Published: June 2007

Granuloma of the nose which does not heal is a tripartite disease, including classical malignant granuloma, Wegener's granulomatosis, and a third group with neoplastic characteristics (granuloma gangrenescens). Five cases of this third type are described and 20 others from the literature are tabulated. The primary lesion is in the nasal or palatal region; after a latent period, metastases develop in many organs. The histological features are those of malignancy. Reasons are given for regarding the condition as a sarcoma of the reticulo endothelial system.
POLYARTERITIS NODOSA AND CONGENITAL PYLORIC HYPERTROPHY IN A 3-MONTH-OLD INFANT
Authors: Savage T. R. , Smith J. F.
Published: June 2007

A case of polyarteritis nodosa in the first year of life with the clinical picture dominated by pyrexia, an initial upper respiratory element, episodes of tachycardia, and sudden death three weeks after the onset is described. The necropsy showed evidence of polyarteritis nodosa, myocarditis, and valvulitis as well as congenital pyloric hypertrophy. Clinical manifestations of the latter had preceded the final illness and the two diseases were not thought to be related.

The previous 19 cases reported in the first year of life are reviewed, and support is given for the concept that at this age a rash, pyrexia, upper respiratory manifestations, and progressive heart failure or sudden death are characteristic clinical manifestations and that the heart is often the site of the major lesions at necropsy.

The possible role of hypersensitivity is discussed. There was no evidence for it in the present case.
A COMPARISON OF THE ROSE-WAALER, LATEX FIXATION, “RA-TEST,” AND BENTONITE FLOCCULATION TESTS
Authors: Greenbury C. L. , Keningale J.
Published: June 2007

The bentonite flocculation test of Bozicevich, Bunim, Freund, and Ward (1958), the latex fixation test of Singer and Plotz (1956), and the “RA-test” (a latex reagent for use as a slide test) of Hyland Laboratories have been compared with each other and with a modified Rose-Waaler test, the behaviour of which has been previously extensively investigated. In these tests sera from 2,250 patients were tested by two or more methods on 3,000 occasions. The findings of this trial are set out and the merits of the tests and reasons for disagreement among them are discussed. It is concluded that the most satisfactory means of testing rheumatoid sera is by the Rose-Waaler test and the “RA-test,” or a satisfactory modification of it, in parallel.
THE SPECIFICITY OF THE SABIN-FELDMAN DYE TEST WITH REFERENCE TO PROTOZOAL INFECTIONS
Authors: Kulasiri C.
Published: June 2007

Infections ofEimeria stiedaein normal and splenectomized rabbits and ofLeishmania enriettiiin normal rabbits and guinea-pigs and in splenectomized rabbits did not produce dye test antibodies. Guinea-pigs injected withAtoxoplasma sp.and rabbits immunized with cultures ofCrithidia fasciculatawere found to be negative for dye test antibodies. Mice which had been infected withTrypanosoma cruzidid not show dye test antibodies. All these animals, except one guinea-pig infected withLeishmania enriettii,were negative in the complement-fixation test for toxoplasmosis using the egg antigen. These findings are discussed in the light of previous reports.
N-ACETYL-β-GLUCOSAMINIDASE ACTIVITY IN SERUM DURING PREGNANCY
Authors: Walker P. G. , Woollen Mary E. , Pugh Doreen
Published: June 2007

A spectrophotometric method for the estimation of N-acetyl-β-glucosaminidase in serum has been devised. Sera from normal adult males and females showed similar levels of activity.

The activity in serum rose progressively during pregnancy and fell rapidly after parturition to normal levels. This change resembled closely that which occurs in serum β-glucuronidase.

Placenta showed a moderate and chorion a high level of N-acetyl-β-glucosaminidase. High N-acetyl-β-glucosaminidase activity was demonstrated histochemically in decidual cells.

The functions of N-acetyl-β-glucosaminidase and β-glucuronidase and factors influencing their activity are discussed.
DETERMINATION OF MAGNESIUM BY THE TITAN YELLOW AND AMMONIUM PHOSPHATE METHODS
Authors: Heaton F. W.
Published: June 2007

The ammonium phosphate and Titan yellow methods for determining magnesium have been investigated, and improvements to both techniques are presented. The Titan yellow method is shown to be subject to interference which makes it unsuitable for the analysis of blood cells, food, and faecal materials, and may also affect its reliability with pathological samples of serum and urine. The relative insusceptibility to interference of the ammonium phosphate method makes it more reliable than the Titan yellow method with pathological specimens, and slight modifications permit the use of the same basic procedure with blood, urine, and solutions of food or faecal ash.