bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Cholesterol Oxidase from Streptomyces hygroscopicus and Brevibacterium sterolicum
Authors: Gadda Giovanni , Wels Gaby , Pollegioni Loredano , Zucchelli Silvia , Ambrosius Dorothea , Pilone Mirella S. , Ghisla Sandro
Published: September 2004

The FAD‐containing enzyme cholesterol oxidase catalyzes the oxidation and isomerization of 3β‐hydroxysteroids having a trans double bond at Δ5‐Δ6 of the steroid ring backbone to the corresponding Δ4‐3‐ketosteroid. Two representative enzymes of this family, namely cholesterol oxidase from Streptomyces hygroscopicus (SCO) and the recombinant enzyme from Brevibacterium sterolicum (BCO) expressed in Escherichia coli, have been characterized herein in their chemical, physical, and biochemical properties. In the native form, both enzymes are monomeric (55 kDa), acidic (pI 4.4–5.1) and contain oxidized FAD (peaks in the 370–390‐nm and 440–470‐nm regions). Marked differences exist between the oxidized, reduced, and (red) anion semiquinone spectra of the two enzymes, suggesting substantial differences in the flavin microenvironment. Both enzymes form reversibly flavin N(5)‐sulfite adducts via measurable kon and koff steps. BCO has a higher affinity for sulfite (Kd≈ 0.14 mM) compared to SCO (≈24 mM). This correlates well with the midpoint redox potentials of the bound flavin, which in the case of BCO are about 100 mV more positive than for SCO. Both enzymes show a high pKa (≈11.0) for the N(3) position of FAD. With both enzymes, the rearrangement of 5‐cholesten‐3‐one to 4‐cholesten‐3‐one is not rate limiting indicating that the rate‐limiting step of the overall reaction is not the isomerization. The absence of the double bond in the steroid molecule does not significantly affect turnover and affinity for the substrate, whereas both these parameters are affected by a decreasing length of the substrate C17 chain.
Ethanolamine, but not Phosphoethanolamine, Potentiates the Effects of Insulin, Phosphocholine, and ATP on DNA Synthesis in NIH 3T3 Cells
Authors: Kiss Zoltan , Mukherjee Jagat J. , Crilly Karan S. , Chung Taeowan
Published: September 2004

NIH 3T3 fibroblasts express a phospholipase D activity hydrolyzing phosphatidylethanolamine (PtdEtn) which produces ethanolamine (Etn) in response to a variety of growth regulating agents. The main objective of this work was to evaluate the effects of Etn on mitogenesis and to determine whether these effects require its metabolism to phosphoethanolamine (PEtn) or PtdEtn. To increase conversion of Etn to PEtn, an Etn‐specific kinase derived from Drosophila was highly expressed in NIH 3T3 cells. Overexpression of this Etn kinase resulted in large (10–12.5‐fold) increases in PEtn formation, but only in modest (1.2–1.7‐fold) increases in PtdEtn synthesis. In both vector control and Etn kinase overexpressor cells, Etn had biphasic effects on insulin‐induced DNA synthesis with maximal (≈ 2‐fold) potentiating effects being observed at 0.5–1 mM concentrations, followed by an inhibitory phase at higher Etn concentrations. In the Etn kinase overexpressor lines, the inhibitory phase was elicited by lower Etn concentrations and it was partially blocked by 5 mM choline due to decreased formation of PEtn. In both vector control and Etn kinase overexpressor cells, phosphocholine (PCho) and insulin synergistically stimulated DNA synthesis; their effects were further enhanced by physiologically relevant (5–60 μM) concentrations of Etn by a mechanism independent of mitogen‐activated protein (MAP) kinase. Concentrations of Etn > 50 μM also enhanced the effects of both PCho and the synergistic effects of PCho plus ATP; however, in the latter case 20 μM Etn was inhibitory. The magnitude of both the potentiating and inhibitory effects of Etn on PCho‐induced as well as PCho + ATP‐induced DNA synthesis were similar in the vector control and Etn kinase overexpressor cells; they were associated with stimulation and inhibition, respectively, of p42 MAP kinase activity. The results indicate that in NIH 3T3 cells Etn exerts significant effects on DNA synthesis which, except inhibition of insulin‐induced DNA synthesis by higher concentrations of Etn, do not correlate with the metabolism of Etn to PEtn or PtdEtn.
The NuoI Subunit of the Rhodobacter Capsulatus Respiratory Complex I (Equivalent to the Bovine TYKY Subunit) is Required for Proper Assembly of the Membraneous and Peripheral Domains of the Enzyme
Authors: Chevallet Mireille , Dupuis Alain , Lunardi Joël , Van Belzen Ronald , Albracht Simon P. J. , Issartel Jean‐Paul
Published: September 2004

The nuoI gene that encodes a ferredoxin‐like subunit of the Rhodobacter capsulatus Complex I (a subunit equivalent to the bovine TYKY subunit) was mutated by homologous recombination. Both a nuoI‐deleted mutant (ΔnuoI mutant) and a point mutant in which Cys74 was replaced by a serine (C74S mutant) proved to be completely deficient in Complex I activity. These strains were unable to grow under anaerobic photosynthetic conditions. Their cytoplasmic membranes were also characterized by the absence of specific EPR signals assigned to FeS clusters N1 and N2. Immunochemical analysis of the mutant membranes with subunit‐specific antibodies showed that the peripheral subunits were not assembled. Trans‐complementation of the mutant strains by a native nuoI gene restored the wild‐type phenotypes. In the C74S mutant, a limited amount of NuoI subunit still bound to the membraneous domain of Complex I, which is an indication that NuoI directly interacts with this domain. All these results clearly show that NuoI plays a critical role in the connection between the membraneous domain and the peripheral domain of Complex I.
Yeast Hexokinase PII
Authors: Maity Haripada , Jarori Gotam K.
Published: September 2004

The structure of adenine nucleotide bound at the active site of yeast hexokinase PII (PII) was studied in the complexes PII · ADPMg(II), PII · ADPMg(II) · Glc and PII · ADPMg(II) · NO3−· Glc using two‐dimensional transferred NOE spectroscopy. Binding of the nucleotide ligand to the enzyme resulted in downfield shift of several ligand resonances. Changes in the chemical shift as a function of ligand concentration indicate that various resonances in the bound and free form of the ligand appear to be in fast exchange. The largest chemical shift change between the bound and the free states (ΔvM= 88 ± 9 Hz) at an NMR frequency of 500 MHz was observed for the H2 resonance of the adenine ring. A lower limit for the rate of ligand dissociation from the complex derived from these results is koff > 550 −1 Interproton NOEs for various ligand protons in PII · ADPMg(II), PII · ADPMg(II) · Glc and PII · ADPMg(II) · NO−3· Glc complexes were measured at 500 MHz at 10°C. The NOE buildup curves constructed from such measurements made at various mixing times (40, 80, 120, 160 and 200 ms) were analyzed using complete relaxation matrix calculations and various interproton distances were determined. These distances were used in restrained molecular dynamics calculations to derive the conformation of the nucleotide bound at the active site of the enzyme. The results of these calculations indicate that the nucleotide binds in an anti conformation. The glycosidic torsion angle x(O4′‐C1′‐N9‐C8) determined for the nucleotide in PII · ADPMg(II), PII · ADPMg(II) · Glc and PII · ADPMg(II) · NO3−· Glc complexes are 68 ± 4o, 52 ± 4o and 49 ± 4o respectively. In all these complexes, the ribose pucker is best represented by the unsymmetrical O4′‐endo‐C1′‐exo twist (oT1). The observed decrease in the glycosidic torsion angle of the bound nucleotide is attributed to the glucose‐induced conformational changes in the enzyme. The structure of the nucleotide derived here is at variance from the one proposed on the basis of X‐ray crystallography and model building [Shoham, M. & Steitz, T. A. (1980) J. Mol. Biol. 140, 1–14].
Structural Constraints in Protein Engineering
Authors: Chen Ridong , Greer Ann F. , Dean Antony M.
Published: September 2004

In a previous study we reported on the successful inversion of coenzyme specificity in isocitrate dehydrogenase (IDH) from NADP to NAD [Chen, R., Greer, A. & Dean, A. M. (1995) A highly active decarboxylating dehydrogenase with rationally inverted coenzyme specificity, Proc. Natl Acad. Sci. USA 92, 11 666–11670]. Here, we explore alternative means to generate NAD dependence in the NADP dependent scaffold of Escherichia coli IDH. The results reveal that engineering a preference for NAD is constrained by the architecture of the IDH coenzyme binding pocket and confirms that the substituted Asp344 in the engineered enzyme is the major determinant of coenzyme specificity. Mutations in the 316–325 loop, which forms part of the coenzyme binding site, reduce activity through transmission of long‐range conformational changes into the active site some 14 Å distant. Conformational changes seen upon substituting Cys332→Tyr are not directly involved with improving activity. Replacements at Cys201 reveal that subtle changes in the packing of hydrophobic residues (Met and Ile versus Leu) can elicit markedly different responses. We caution against using sequence alignments as the sole guide for mutagenesis and show how a combination of rational design of active‐site residues based on X‐ray structures and random substitutions at surrounding residues provides an efficient means to improve enzyme preference and catalytic efficiency towards novel substrates.
Modelling ductile fracture behaviour from deformation parameters in HSLA steels
Authors: SIVAPRASAD S. , TARAFDER S. , RANGANATH V. R. , RAY K. K.
Published: September 2004

In this work, an attempt is made to model the ductile fracture behaviour of two Cu‐strengthened high strength low alloy (HSLA) steels through the understanding of their deformation behaviour. The variations in deformation behaviour are imparted by prior deformation of steels to various predetermined strains. The variations in parameters such as yield strength and true uniform elongation with prior deformation is studied and was found to be analogous to that of initiation fracture toughness determined by independent method. A unique method is used to measure the crack tip deformation characterized by stretch zone depth that also depicted a similar trend. Fracture toughness values derived from the stretch zone depth measurements were found to vary in the same fashion as the experimental values. A semiempirical relationship for obtaining ductile fracture toughness from basic deformation parameters is derived and model is demonstrated to estimate initiation ductile fracture toughness accurately.
Diversity of Frankia strains associated to Myrica gale in Western Europe: impact of host plant (Myrica vs. Alnus) and of edaphic factors
Authors: Huguet Valérie , Mergeay Max , Cervantes Emilio , Fernandez Maria P.
Published: September 2004

Myricaceae can be nodulated by a variety of Frankia strains isolated from other actinorhizal families. Consequently, the genus Myrica has been considered to have low specificity with respect to microsymbiont taxa. In contrast to controlled studies of Myrica infectious capacity, field studies in North America have indicated that M. gale symbionts belong to the genetic group of Alnus‐infective strains. Myrica gale is the most widely distributed species in the genus so this study focused on describing the genetic diversity of M. gale‐nodulating strains from 10 sites in Western Europe across a range of edaphic conditions. When possible, the specificity of M. gale‐infective strains was compared with that of Alnus‐infective strains from the same sites. Nodular strains from Belgium, France and Spain were characterized using PCR‐RFLP of rrs gene and 16S‐23S IGS. rrs‐RFLP patterns showed a high level of homogeneity among European strains with one dominant genotype. IGS‐RFLP patterns revealed the largest inter and intrasite diversity in France. In Belgium, Frankia strains were found to occur in two groups according to soil pH and organic matter characteristics of the sites. European M. gale‐infective strains were genetically different from European Alnus and North American M. gale‐infective strains indicating the possibility of different pathways of co‐evolution among geographically isolated populations.
Intracellular manganese granules formed by a subsurface bacterium
Authors: Glasauer Susan , Langley Sean , Beveridge Terry J.
Published: September 2004

The demonstrated ability of prokaryotes to form internal metal oxide particles during active metabolism has been restricted to Fe. Mineral‐bound Mn(IV) is a known electron acceptor during dissimilatory metal reduction by Shewanella putrefaciens, yet no internal deposits of Mn have been reported to form during anaerobic respiration. We observed distinct nanometre‐sized Mn‐rich granules in the cytoplasm when either birnessite or pyrolusite (β‐MnO2) served as the electron acceptor during growth. During rapid Mn reduction, additional precipitates of Mn were also observed in the periplasm together with the cytoplasmic granules. The bacteria did not accumulate detectable Mn in the outer membrane during formation of the internal precipitates. This is the first report of an intracellular Mn solid produced by bacteria and coupled anaerobically to DR.
Impact of lime, nitrogen and plant species on bacterial community structure in grassland microcosms
Authors: Kennedy Nabla , Brodie Eoin , Connolly John , Clipson Nicholas
Published: September 2004

A microcosm‐based approach was used to study impacts of plant and chemical factors on the bacterial community structure of an upland acidic grassland soil. Seven perennial plant species typical of both natural, unimproved (Nardus stricta, Agrostis capillaris, Festuca ovina and F. rubra) and fertilized, improved (Holcus lanatus, Lolium perenne and Trifolium repens) grasslands were either left unamended or treated with lime, nitrogen, or lime plus nitrogen in a 75‐day glasshouse experiment. Lime and nitrogen amendment were shown to have a greater effect on microbial activity, biomass and bacterial ribotype number than plant species. Liming increased soil pH, microbial activity and biomass, while decreasing ribotype number. Nitrogen addition decreased soil pH, microbial activity and ribotype number. Addition of lime plus nitrogen had intermediate effects, which appeared to be driven more by lime than nitrogen. Terminal restriction fragment length polymorphism (TRFLP) analysis revealed that lime and nitrogen addition altered soil bacterial community structure, while plant species had little effect. These results were further confirmed by multivariate redundancy analysis, and suggest that soil lime and nitrogen status are more important controllers of bacterial community structure than plant rhizosphere effects.
Estimating bacterial diversity from clone libraries with flat rank abundance distributions
Authors: Lunn Mary , Sloan William T. , Curtis Thomas P.
Published: September 2004

There are a number of parametric and non‐parametric methods for estimating diversity. However all such methods employ either the proportional abundance of the most abundant taxon in a sample or require that a specific taxon is sampled more than once. Consequently, the available methods for estimating diversity cannot be applied to samples consisting entirely of singletons, which might be characteristic of some hyperdiverse communities. Here we present a non‐parametric method that estimates the probability that a given number of unique taxa would be sampled from a community with a particular diversity. We have applied this approach to a well known data set of 100 unique clones from a sample of Amazonian soil (Borneman and Triplett (1997) Appl Environ Microbiol 63: 2647–2653) and determine the probability that this observation would be made from an environment of a given diversity. On this basis we can state this observation would be very unlikely (P = 0.006) if the soil diversity was less than 103, and quite unlikely (P = 0.6) if the diversity was less than 104, and probable (P = 0.95) if the diversity was about 105. There are essentially no contestable assumptions in our method. Thus we are able to offer almost unequivocal evidence that the bacterial diversity, of at least soils, is very large and a method that may be used to interpret samples consisting entirely of singletons from other hyperdiverse communities.
Illuminating the detection chain of bacterial bioreporters
Authors: Van Der Meer Jan Roelof , Tropel David , Jaspers Marco
Published: September 2004

Engineering bacteria for measuring chemicals of environmental or toxicological concern (bioreporter bacteria) has grown slowly into a mature research area. Despite many potential advantages, current bioreporters do not perform well enough to comply with environmental detection standards. Basically, the reasons for this are the lack of engineering principles in the detection chain in the bioreporters. Here, we dissect critical steps in the detection chain and illustrate how bioreporter design could be improved by mutagenizing specificity and selectivity of the sensing and regulatory proteins, by newer expression strategies and application of different signalling networks. Furthermore, we describe how redesigning bioreporter assays with respect to pollutant transport into the cells and application of other detection devices can decrease detection limits and increase the speed of detection.
Foreign Equity Ownership and Information Asymmetry: Evidence from Japan
Authors: Jiang Li , Kim Jeong‐Bon
Published: September 2004

Using a large sample of Japanese firms, we investigate whether the level of foreign ownership in a firm is inversely related to information asymmetry between firm (managers) and market (outside investors). Since information asymmetry is not directly observable and, thus, is difficult to measure empirically, our analysis focuses on the link between foreign shareholding and a measurable consequence of information asymmetry; that is, the timing and magnitude of intertemporal return‐earnings associations. The empirical results support our hypothesis, and subsequent tests based on residual foreign ownership show that the relation between foreign ownership and information asymmetry is robust to the addition of various control variables such as market capitalization and cross‐corporate holdings. We also show that foreign investors tend to avoid stocks with high cross‐corporate holdings. Overall, our results suggest that foreign (institutional) investors are likely to be efficient processors of public information and are attracted to Japanese firms with low information asymmetry.
Anomalies and Unusual Patterns in Reported Earnings: Japanese Managers Round Earnings
Authors: Skousen Christopher J. , Guan Liming , Wetzel T. Sterling
Published: September 2004

Using Benford's law, this study documents pervasive evidence that managers of Japanese firms tend to engage in earnings manipulative activities of rounding earnings numbers to achieve key reference points. Similar toCarslaw (1988)andThomas (1989), we find that the first digit of earnings numbers is often emphasized by the management. We also find that key reference points are not limited to the first digit. The second, third, or even fourth digits are sometimes used as the reference points of the rounding earnings behavior. Finally, our results show that the incentives of rounding earnings numbers are negatively associated with the distance of pre‐rounded earnings to the next reference point.
Director Ownership and Voluntary Segment Disclosure: Hong Kong Evidence
Authors: Leung Sidney , Horwitz Bertrand
Published: September 2004

Weakness of corporate governance and lack of transparency are often considered causes of or contributors to the Asian Financial Crisis. Publicly listed companies in Hong Kong, like other Asian firms, have concentrated director ownership. The study uses voluntary segment disclosure above the benchmark minimum as a proxy for transparency and examines its relationship to the ownership structure and composition of corporate boards in Hong Kong. We find that: (1) high (concentrated) board ownership explains the extent of low voluntary segment disclosure and this negative relationship is stronger when firm performance is very poor; (2) the contribution of non‐executive directors to enhance voluntary segment disclosure is effective for firms with low director ownership but not for concentrated‐ownership firms. These results have implications for policy makers and regulators in the Asia‐Pacific region striving to improve governance and transparency.
Risk Sensitivity of Bank Stocks in Malaysia: Empirical Evidence Across the Asian Financial Crisis
Authors: Hooy Chee Wooi , Tan Hui Boon , Nassir Annuar Md
Published: September 2004

The present study examines the sensitivity of commercial banks’ stock excess returns to their volatility and financial risk factors, measured by interest rates and exchange rates, across the recent Asian financial crisis. In general, we found that there were no significant differences among Malaysian commercial banks in their risk exposure prior to and during the Asian financial crisis. The introduction of selective capital controls, a fixed exchange rate regime and a forced banking consolidation program, however, had increased the risk exposure of both large and small domestic banks. The effects of these risk factors were significantly detected in both large and small banks.
Bayesian Updating of Atmospheric Dispersion After a Nuclear Accident
Authors: Politis Konstadinos , Robertson Lennart
Published: September 2004

We consider a Bayesian forecasting system to predict the dispersal of contamination on a large scale grid in the event of an accidental release of radioactivity. The statistical model is built on a physical model for atmospheric dispersion and transport called MATCH. Our spatiotemporal model is a dynamic linear model where the state parameters are the (essentially, deterministic) predictions of MATCH; the distributions of these are updated sequentially in the light of monitoring data. One of the distinguishing features of the model is that the number of these parameters is very large (typically several hundreds of thousands) and we discuss practical issues arising in its implementation as a realtime model. Our procedures have been checked against a variational approach which is used widely in the atmospheric sciences. The results of the model are applied to test data from a tracer experiment.
Simple Component Analysis
Authors: Rousson Valentin , Gasser Theo
Published: September 2004

With a large number of variables measuring different aspects of a same theme, we would like to summarize the information in a limited number of components, i.e. linear combinations of the original variables. Among linear dimension reduction techniques, principal component analysis is optimal in at least two ways: principal components extract the maximum of the variability of the original variables, and they are uncorrelated. Unfortunately, they are often difficult to interpret. Moreover, in most applications, only the first principal component is a ‘block component’, the remaining components being ‘difference components’ which are also more difficult to interpret. The goal of simple component analysis is to replace (or to supplement) principal components with suboptimal but better interpretable ‘simple components’. We propose a fast algorithm which seeks the optimal system of components under constraints of simplicity. Thus, in contrast with other techniques like ‘varimax’, this approach always provides a simple solution. The optimal simple system is suboptimal compared with principal components: less variability is extracted and components are correlated. However, if the loss of extracted variability is small, and correlations between components are low, it might be advantageous for practical use. Moreover, our concept of simplicity allows the system to have more than one block component, which also facilitates interpretation. Simplicity is not a guarantee for interpretability. With the help of our algorithm, the user can partly modify an optimal simple system of components to enhance interpretability. In this respect, the ultimate goal of simple component analysis is not to propose a method that leads automatically to a unique solution, but rather to develop tools for assisting the user in his or her choice of an interpretable solution. Finally, we argue that simple components may also make the task of choosing the dimension easier. The methodology is illustrated with a test battery to study the development of neuromotor functions in children and adolescents.
An expert system on design of liquid‐retaining structures with blackboard architecture
Authors: Chau K.W. , Albermani F.
Published: September 2004

Abstract: The design of liquid‐retaining structures involves many decisions to be made by the designer based on rules of thumb, heuristics, judgement, codes of practice and previous experience. Structural design problems are often ill structured and there is a need to develop programming environments that can incorporate engineering judgement along with algorithmic tools. Recent developments in artificial intelligence have made it possible to develop an expert system that can provide expert advice to the user in the selection of design criteria and design parameters. This paper introduces the development of an expert system in the design of liquid‐retaining structures using blackboard architecture. An expert system shell, Visual Rule Studio, is employed to facilitate the development of this prototype system. It is a coupled system combining symbolic processing with traditional numerical processing. The expert system developed is based on British Standards Code of Practice BS8007. Explanations are made to assist inexperienced designers or civil engineering students to learn how to design liquid‐retaining structures effectively and sustainably in their design practices. The use of this expert system in disseminating heuristic knowledge and experience to practitioners and engineering students is discussed.
Automated generation of new knowledge to support managerial decision‐making: case study in forecasting a stock market
Authors: Chun Se‐Hak , Kim Steven H.
Published: September 2004

Abstract: The deluge of data available to managers underscores the need to develop intelligent systems to generate new knowledge. Such tools are available in the form of learning systems from artificial intelligence. This paper explores how the novel tools can support decision‐making in the ubiquitous managerial task of forecasting.

For concreteness, the methodology is examined in the context of predicting a financial index whose chaotic properties render the time series difficult to predict. The study investigates the circumstances under which enough new knowledge is extracted from temporal data to overturn the efficient markets hypothesis.

The efficient markets hypothesis precludes the possibility of anticipating in financial markets. More precisely, the markets are deemed to be so efficient that the best forecast of a price level for the subsequent period is precisely the current price. Certain anomalies to the efficient market premise have been observed, such as calendar effects. Even so, forecasting techniques have been largely unable to outperform the random walk model which corresponds to the behavior of prices under the efficient markets hypothesis.

This paper tests the validity of the efficient markets hypothesis by developing knowledge‐based tools to forecast a market index. The predictions are examined across several horizons: single‐period forecasts as well as multiple periods. For multiperiod forecasts, the predictive methodology takes two forms: a single jump from the current period to the end of the forecast horizon, and a multistage web of forecasts which progresses systematically from one period to the next.

These models are first evaluated using neural networks and case‐based reasoning, and are then compared against a random walk model. The computational models are examined in the context of forecasting a composite for the Korean stock market.
Evolving modular networks with genetic algorithms: application to nonlinear time series
Authors: Cofiño A.S. , Gutiérrez J.M. , Ivanissevich M.L.
Published: September 2004

Abstract:A key problem of modular neural networks is finding the optimal aggregation of the different subtasks (or modules) of the problem at hand. Functional networks provide a partial solution to this problem, since the inter‐module topology is obtained from domain knowledge (functional relationships and symmetries). However, the learning process may be too restrictive in some situations, since the resulting modules (functional units) are assumed to be linear combinations of selected families of functions. In this paper, we present a non‐parametric learning approach for functional networks using feedforward neural networks for approximating the functional modules of the resulting architecture; we also introduce a genetic algorithm for finding the optimal intra‐module topology (the appropriate balance of neurons for the different modules according to the complexity of their respective tasks). Some benchmark examples from nonlinear time‐series prediction are used to illustrate the performance of the algorithm for finding optimal modular network architectures for specific problems.
The History and Development of the Dental Surveyor—Part III
Authors: Engelmeier Robert L.
Published: September 2004

The third and final installment of this series reviews noteworthy instruments that have not enjoyed the commercial success of those discussed in Parts I and II.
Testing the Efficacy of a Creative‐Arts Intervention With Family Caregivers of Patients With Cancer
Authors: Walsh Sandra M. , Martin Susan Culpepper , Schmidt Lee A.
Published: September 2004

Purpose

: To test the efficacy of a creative arts intervention (CAI) with family caregivers of patients with cancer.

Design

: A pre‐posttest quasi‐experimental design, with participation in the CAI as the independent variable and stress, anxiety, and emotions as the dependent variables.

Method

: The 6‐month study was implemented at a regional cancer treatment center with family caregivers. The CAI consisted of several creative arts activities designed for delivery at the bedside.

Findings

: Forty family caregivers reported significantly reduced stress, lowered anxiety, and increased positive emotions following CAI participation.

Conclusions

: The CAI promoted short‐term well being in this family caregiver sample. Caregivers also increased positive communication with cancer patients and health care providers while expressing delight over their handmade pieces of art.
Becoming a Mother Versus Maternal Role Attainment
Authors: Mercer Ramona T.
Published: September 2004

Purpose

: To present evidence for replacing the term maternal role attainment (MRA), with becoming a mother (BAM).

Methods

: A review of the evolution of MRA and a synthesis of research emanating from the theory was done, followed by synthesis of current research on the transition to motherhood.

Findings

: A woman establishes maternal identity as she becomes a mother through her commitment to and involvement in defining her new self. Maternal identity continues to evolve as the mother acquires new skills to regain her confidence in self as new challenges arise.

Conclusions

: BAM more accurately encompasses the dynamic transformation and evolution of a woman's persona than does MRA, and the term MRA should be discontinued.
Working With Human Research Protections
Authors: Arford Patricia H.
Published: September 2004

Purpose

: To provide a primer for novice nurse scientists about the increasingly regulated human research environment.

Organizing Constructs

: Federal regulations and international guidelines about protection of human research participants are discussed, with particular attention to institutional review boards for human research.

Conclusion

: Understanding the processes used by institutional review boards to foster ethical human research promotes collaborative interactions and supports compliant research work.
A Dimensional Analysis of Role Enactment of Acute Care Nurses
Authors: Squires Allison
Published: September 2004

Purpose

: To identify dimensions of the role enactment process of acute care nurses.

Design

: Dimensional analysis, rooted in grounded theory methodology, was used to analyze the role enactment process.

Methods

: Twenty‐eight articles related to acute care staff nurse roles were selected for analysis. Articles were from eight countries and were published between 1995 and 2002. Significant phrases or themes from each document were categorized to identify themes.

Findings

: Initial analysis of the articles indicated 37 separate dimensions in the role enactment process of acute care nurses. The final, integrative analysis reduced the initial 37 to 7 core dimensions: care delivery, autonomy, culture management, information management, leadership, psychologic management, and relationship management. The analysis showed a role that is rooted in management processes.

Conclusions

: The multidimensional nature of the role of acute care nurses was indicated in the dimensional analysis. The findings have implications for the administration and education of nurses, as well as for human resource development of nurses in many parts of the world.
External and Internal Morphology of the BAR 1002'00
Orrorin tugenensis
Femur
Authors: Galik K. , Senut B. , Pickford M. , Gommery D. , Treil J. , Kuperavage A. J. , Eckhardt R. B.
Published: September 2004

Late Miocene fossils from the Lukeino Formation in Kenya's Tugen Hills are assigned to
Orrorin tugenensis
. Of 20 fossils recovered there to date, 3 are proximal femurs. One of these, BAR 1002′00, preserves an intact head connected to the proximal shaft by an elongated neck. Although this fossil is comparable in size to
Pan troglodytes
, computerized tomography scans of the neck-shaft junction of BAR 1002′00 reveal that the cortex is markedly thinner superiorly than inferiorly, differing from the approximately equal cortical thicknesses observed in extant African apes, approaching the condition in later hominids, and indicating that
O. tugenensis
was bipedal.
Macroscopic, Neat, Single-Walled Carbon Nanotube Fibers
Authors: Ericson Lars M. , Fan Hua , Peng Haiqing , Davis Virginia A. , Zhou Wei , Sulpizio Joseph , Wang Yuhuang , Booker Richard , Vavro Juraj , Guthy Csaba , Parra-Vasquez A. Nicholas G. , Kim Myung Jong , Ramesh Sivarajan , Saini Rajesh K. , Kittrell Carter , Lavin Gerry , Schmidt Howard , Adams W. Wade , Billups W. E. , Pasquali Matteo , Hwang Wen-Fang , Hauge Robert H. , Fischer John E. , Smalley Richard E.
Published: September 2004

Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical properties.
The Embryo of a Dialogue
Authors: Wagner Günter P.
Published: September 2004

Embryology, Epigenesis, and Evolution
Taking Development Seriously. by Jason Scott Robert. Cambridge University Press, Cambridge, 2004. 174 pp. $60, £40. ISBN 0-521-82467-2. Studies in Philosophy and Biology.

This contribution to the Cambridge Studies in Philosophy and Biology explores development in the context of recent evo-devo research and work on biological theory and practice.
What Can Progeroid Syndromes Tell Us About Human Aging?
Authors: Kipling David , Davis Terence , Ostler Elizabeth L. , Faragher Richard G. A.
Published: September 2004

Human genetic diseases that resemble accelerated aging provide useful models for gerontologists. They combine known single-gene mutations with deficits in selected tissues that are reminiscent of changes seen during normal aging. Here, we describe recent progress toward linking molecular and cellular changes with the phenotype seen in two of these disorders. One in particular, Werner syndrome, provides evidence to support the hypothesis that the senescence of somatic cells may be a causal agent of normal aging.
Influence of Complex Nutrient Source on Growth of and Curvacin A Production by Sausage Isolate
Lactobacillus curvatus
LTH 1174
Authors: Verluyten Jurgen , Leroy Frédéric , de Vuyst Luc
Published: September 2004

Lactobacillus curvatus
LTH 1174, a fermented sausage isolate, produces the antilisterial bacteriocin curvacin A. Its biokinetics of cell growth and bacteriocin production as a function of various concentrations of a complex nutrient source were investigated in vitro during laboratory fermentations with modified MRS medium. A modification of the nutrient depletion model (Leroy and De Vuyst, Appl. Environ, Microbiol.
67:
4470-4473, 2001) was used to fit the data describing growth and bacteriocin production. Both cell growth and bacteriocin activity were influenced by changes in the complex nutrient source concentration. Standard MRS medium clearly limited the growth of
L. curvatus
LTH 1174. Higher nutrient concentrations, up to a certain degree, led to improved growth, a higher attainable biomass concentration, and a higher bacteriocin activity in the supernatant. A lower concentration of complex nutrient source caused severe growth inhibition, leading to a lower biomass concentration but a much higher specific bacteriocin production. When examining the separate components of the complex nutrient source, a stimulating effect of bacteriological peptone on growth was found without an adverse effect on bacteriocin production, resulting in increased curvacin A activity. Furthermore, specific depletion of the amino acids tyrosine, serine, and asparagine/aspartic acid was observed for this strain.
Surveillance of Bulk Raw and Commercially Pasteurized Cows' Milk from Approved Irish Liquid-Milk Pasteurization Plants To Determine the Incidence of
Mycobacterium paratuberculosis
Authors: O'Reilly Ciara E. , O'Connor Lisa , Anderson Wayne , Harvey Peter , Grant Irene R. , Donaghy John , Rowe Michael , O'Mahony Pat
Published: September 2004

Over the 13-month period from October 2000 to November 2001 (inclusive), the Food Safety Authority of Ireland (FSAI) carried out surveillance of Irish bulk raw (
n
= 389) and commercially pasteurized (
n
= 357) liquid-milk supplies to determine the incidence of
Mycobacterium paratuberculosis
. The pasteurization time-temperature conditions were recorded for all pasteurized samples. Overall, 56% of whole-milk pasteurized samples had been heat treated at or above a time-temperature combination of 75°C for 25 s. All analyses were undertaken at the Department of Food Science (Food Microbiology) laboratory at Queen's University Belfast. Each milk sample was subjected to two tests for
M. paratuberculosis
: immunomagnetic separation-PCR (IMS-PCR; to detect the presence of
M. paratuberculosis
cells, live or dead) and chemical decontamination and culture (to confirm the presence of viable
M. paratuberculosis
). Overall,
M. paratuberculosis
DNA was detected by IMS-PCR in 50 (12.9%; 95% confidence interval, 9.9 to 16.5%) raw-milk samples and 35 (9.8%; 95% confidence interval, 7.1 to 13.3%) pasteurized-milk samples. Confirmed
M. paratuberculosis
was cultured from one raw-milk sample and no pasteurized-milk samples. It is concluded that
M. paratuberculosis
DNA is occasionally present at low levels in both raw and commercially pasteurized cows' milk. However, since no viable
M. paratuberculosis
was isolated from commercially pasteurized cows' milk on retail sale in the Republic of Ireland, current pasteurization procedures are considered to be effective.
Pulsed-Field Gel Electrophoresis Analysis of
Vibrio vulnificus
Strains Isolated from Taiwan and the United States
Authors: Wong Hin-chung , Chen Shau-Yan , Chen Meng-Yi , Oliver James D. , Hor Lien-I , Tsai Wen-Cherng
Published: September 2004

Vibrio vulnificus
is a marine bacterium that causes human wound infections and septicemia with a high mortality rate.
V. vulnificus
strains from different clinical and environmental sources or geographic regions have been successfully characterized by ribotyping and several other methods. Pulsed-field gel electrophoresis (PFGE) is a highly discriminative method, but previous studies suggested that it was not suitable for examining the correlation of
V. vulnificus
strains from different origins. We employed PFGE to determine its efficacy for characterizing
V. vulnificus
strains from different geographic regions, characterizing a total of 153 strains from clinical and environmental origins from the United States and Taiwan after SfiI or NotI digestion.
V. vulnificus
strains showed a high intraspecific diversity by PFGE after SfiI or NotI digestion, and about 12% of the strains could not be typed by the use of either of these enzymes. For PFGE with SfiI digestion, most of the clinical and environmental strains from the United States were grouped into cluster A, while the strains from Taiwan were grouped into other clusters. Clinical strains from the United States showed a higher level of genetic homogeneity than clinical strains from Taiwan, and environmental strains from both regions showed a similarly high level of heterogeneity. PFGE with NotI digestion was useful for studying the correlation of clinical strains from the United States and Taiwan, but it was not suitable for analyzing environmental strains. The results showed that PFGE with SfiI digestion may be used to characterize
V. vulnificus
strains from distant geographic regions, with NotI being a recommended alternative enzyme.
Substrate-Induced Production and Secretion of Cellulases by
Clostridium acetobutylicum
Authors: López-Contreras Ana M. , Gabor Krisztina , Martens Aernout A. , Renckens Bernadet A. M. , Claassen Pieternel A. M. , van der Oost John , de Vos Willem M.
Published: September 2004

Clostridium acetobutylicum
ATCC 824 is a solventogenic bacterium that grows heterotrophically on a variety of carbohydrates, including glucose, cellobiose, xylose, and lichenan, a linear polymer of β-1,3- and β-1,4-linked β-
d
-glucose units.
C. acetobutylicum
does not degrade cellulose, although its genome sequence contains several cellulase-encoding genes and a complete cellulosome cluster of cellulosome genes. In the present study, we demonstrate that a low but significant level of induction of cellulase activity occurs during growth on xylose or lichenan. The
celF
gene, located in the cellulosome-like gene cluster and coding for a unique cellulase that belongs to glycoside hydrolase family 48, was cloned in
Escherichia coli
, and antibodies were raised against the overproduced CelF protein. A Western blot analysis suggested a possible catabolite repression by glucose or cellobiose and an up-regulation by lichenan or xylose of the extracellular production of CelF by
C. acetobutylicum
. Possible reasons for the apparent inability of
C. acetobutylicum
to degrade cellulose are discussed.
Contribution of Fungi and Bacteria to Leaf Litter Decomposition in a Polluted River
Authors: Pascoal Cláudia , Cássio Fernanda
Published: September 2004

The contribution of fungi and bacteria to the decomposition of alder leaves was examined at two reference and two polluted sites in the Ave River (northwestern Portugal). Leaf mass loss, microbial production from incorporation rates of radiolabeled compounds into biomolecules, fungal biomass from ergosterol concentration, sporulation rates, and diversity of aquatic hyphomycetes associated with decomposing leaves were determined. The concentrations of organic nutrients and of inorganic nitrogen and phosphorus in the stream water was elevated and increased at downstream sites. Leaf decomposition rates were high (0.013 day
−1
<
k
< 0.042 day
−1
), and the highest value was estimated at the most downstream polluted site, where maximum values of microbial production and fungal biomass and sporulation were found. The slowest decomposition occurred at the other polluted site, where, along with the nutrient enrichment, the lowest current velocity and dissolved-oxygen concentration in water were observed. At this site, fungal production, biomass, and sporulation were depressed, suggesting that stimulation of fungal activity by increased nutrient concentrations might be offset by other factors. Although bacterial production was higher at polluted sites, fungi accounted for more than 94% of the total microbial net production. Fungal yield coefficients varied from 10.2 to 13.6%, while those of bacteria were less than 1%. The contribution of fungi to overall leaf carbon loss (29.0 to 38.8%) greatly exceeded that of bacteria (4.2 to 13.9%).
Phenotypic and Molecular Typing of
Salmonella
Strains Reveals Different Contamination Sources in Two Commercial Pig Slaughterhouses
Authors: Botteldoorn Nadine , Herman Lieve , Rijpens Nancy , Heyndrickx Marc
Published: September 2004

This study aimed to define the origin of
Salmonella
contamination on swine carcasses and the distribution of
Salmonella
serotypes in two commercial slaughterhouses during normal activity. Salmonellae were isolated from carcasses, from colons and mesenteric lymph nodes of individual pigs, and from the slaughterhouse environment. All strains were serotyped;
Salmonella enterica
serotype Typhimurium and
Salmonella enterica
serotype Derby isolates were additionally typed beyond the serotype level by pulsed-field gel electrophoresis (PFGE) and antibiotic resistance profiling (ARP); and a subset of 31 serotype Typhimurium strains were additionally phage typed. PFGE and ARP had the same discriminative possibility. Phage typing in combination with PFGE could give extra information for some strains. In one slaughterhouse, 21% of the carcasses were contaminated, reflecting a correlation with the delivery of infected pigs. Carcass contamination did not result only from infection of the corresponding pig; only 25% of the positive carcasses were contaminated with the same serotype or genotype found in the corresponding feces or mesenteric lymph nodes. In the other slaughterhouse, 70% of the carcasses were contaminated, and only in 4% was the same genotype or serotype detected as in the feces of the corresponding pigs. The other positive carcasses in both slaughterhouses were contaminated by genotypes present in the feces or lymph nodes of pigs slaughtered earlier that day or from dispersed sources in the environment. In slaughterhouses, complex contamination cycles may be present, resulting in the isolation of many different genotypes circulating in the environment due to the supply of positive animals and in the contamination of carcasses, probably through aerosols.
Identification and Inactivation of Genetic Loci Involved withLactobacillus acidophilusAcid Tolerance
Authors: Azcarate-Peril M. Andrea , Altermann Eric , Hoover-Fitzula Rebecca L. , Cano Raul J. , Klaenhammer Todd R.
Published: September 2004

Amino acid decarboxylation-antiporter reactions are one of the most important systems for maintaining intracellular pH between physiological limits under acid stress. We analyzed theLactobacillus acidophilusNCFM complete genome sequence and selected four open reading frames with similarities to genes involved with decarboxylation reactions involved in acid tolerance in several microorganisms. Putative genes encoding an ornithine decarboxylase, an amino acid permease, a glutamate γ-aminobutyrate antiporter, and a transcriptional regulator were disrupted by insertional inactivation. The ability ofL. acidophilusto survive low-pH conditions, such as those encountered in the stomach or fermented dairy foods, was investigated and compared to the abilities of early- and late-stationary-phase cells of the mutants by challenging them with a variety of acidic conditions. All of the integrants were more sensitive to low pH than the parental strain. Interestingly, each integrant also exhibited an adaptive acid response during logarithmic growth, indicating that multiple mechanisms are present and orchestrated inL. acidophilusin response to acid challenge.