bluuebunny/crossref_metadata_2025 huggingface dataset:
The identification of family members’ contribution to patients’ care in the intensive care unit: a naturalistic inquiry
Authors: Williams Caroline MA
Published: January 2005

• The admission of a patient to an intensive care unit (ICU) is recognized as being a stressful experience for their families

• Many studies have focused on the needs of families within ICU, but few have highlighted the unique contribution that family members make towards patient care and recovery

• Using a naturalistic approach, data were collected through observation, video recording, in‐depth interviewing and reflective video analysis to explore the processes and factors underpinning families’ contribution to patient care

• The findings can be grouped into three themes: getting to know the patient through the family, family contribution to care and the nurses’ role in supporting families of ICU patients

• Families can have a very positive influence on the patient's care and recovery from ICU, but both the family members, and in turn the nursing staff, need to be supported appropriately if this valuable contribution to patient care is to be maximized and maintained
Effects of Holocene climate change on the historical demography of migrating sharp‐shinned hawks (Accipiter striatus velox) in North America
Authors: HULL JOSHUA M. , GIRMAN DEREK J.
Published: January 2005

DNA sequences of the mitochondrial control region were analysed from 298 individual sharp‐shinned hawks (Accipiter striatus velox) sampled at 12 different migration study sites across North America. The control region proved to be an appropriate genetic marker for identification of continental‐scale population genetic structure and for determining the historical demography of population units. These data suggest that sharp‐shinned hawks sampled at migration sites in North America are divided into distinct eastern and western groups. The eastern group appears to have recently expanded in response to the retreat of glacial ice at the end of the last glacial maximum. The western group appears to have been strongly effected by the Holocene Hypsithermal dry period, with molecular evidence indicating the most recent expansion following this mid‐Holocene climatic event 7000–5000 years before present.
Impact of oilseed rape expressing the insecticidal serine protease inhibitor, mustard trypsin inhibitor‐2 on the beneficial predator Pterostichus madidus
Authors: FERRY N. , JOUANIN L. , CECI L. R. , MULLIGAN E. A. , EMAMI K. , GATEHOUSE J. A. , GATEHOUSE A. M. R.
Published: January 2005

Insect‐resistant transgenic plants have been suggested to have deleterious effects on beneficial predators feeding on crop pests, through transmission of the transgene product by the pest to the predator. To test this hypothesis, effects of oilseed rape expressing the serine protease inhibitor, mustard trypsin inhibitor −2 (MTI‐2), on the predatory ground beetle Pterostichus madidus were investigated, using diamondback moth, Plutella xylostella as the intermediary pest species. As expected, oilseed rape expressing MTI‐2 had a deleterious effect on the development and survival of the pest. However, incomplete pest mortality resulted in survivors being available to predators at the next trophic level, and inhibition studies confirmed the presence of biologically active transgene product in pest larvae. Characterization of proteolytic digestive enzymes of P. madidus demonstrated that adults utilize serine proteases with trypsin‐like and chymotrypsin‐like specificities; the former activity was completely inhibited by MTI‐2 in vitro. When P. madidus consumed prey reared on MTI‐2 expressing plants over the reproductive period in their life cycle, no significant effects upon survival were observed as a result of exposure to the inhibitor. However, there was a short‐term significant inhibition of weight gain in female beetles fed unlimited prey containing MTI‐2, with a concomitant reduction of prey consumption. Biochemical analyses showed that the inhibitory effects of MTI‐2 delivered via prey on gut proteolysis in the carabid decreased with time of exposure, possibly resulting from up‐regulation of inhibitor‐insensitive proteases. Of ecological significance, consumption of MTI‐2 dosed prey had no detrimental effects on reproductive fitness of adult P. madidus.
Mating patterns and gene flow in the neotropical epiphytic orchid, Laelia rubescens
Authors: TRAPNELL D. W. , HAMRICK J. L.
Published: January 2005

Understanding mating patterns and gene movement in plant populations occupying highly disturbed landscapes is essential for insights into their long‐term survival. We used allozyme genetic markers to examine mating patterns and to directly measure pollen flow in the Central American epiphytic orchid, Laelia rubescens. Study populations were located in disturbed, seasonally dry tropical forest in Costa Rica. Every flowering individual within 15 populations and 12–18 seedlings from each maternal individual were genotyped over two reproductive seasons. Strict correlated mating by orchids produces full‐sib progeny arrays from which the multilocus diploid genotype of the pollen parent can be inferred. These paternity analyses produced detailed quantitative estimates of pollen movement within and among populations of this species. Although our data illustrate that mating patterns vary spatially and temporally among trees, among pastures, and between years, overall patterns were surprisingly consistent. Thirty‐four per cent of the capsules produced in both years resulted from gene flow events. Where pollen parents were identified, pollen moved mean distances of 279 m and 519 m in 1999 and 2000 respectively and a maximum documented distance of 1034 m. A substantially larger floral display in 2000 corresponded to a marked increase in pollen dispersal distances. Smaller populations, which more closely resembled those in undisturbed forest, had higher rates of gene flow than the large populations that characterize disturbed sites. We predict the occurrence of greater gene flow between low‐density populations occupying undisturbed habitats.
Genetic diversity in perennial ryegrass and white clover among old Dutch grasslands as compared to cultivars and nature reserves
Authors: VAN TREUREN R. , BAS N. , GOOSSENS P. J. , JANSEN J. , VAN SOEST L. J. M.
Published: January 2005

To support conservation policies for old Dutch grasslands that are still in agricultural use, morphological variation and AFLP‐based (amplified fragment length polymorphism‐based) genetic diversity was studied in perennial ryegrass and white clover populations and compared with the diversity in reference varieties. In addition, AFLP variation was also studied in grasslands located in nature reserves. From principal component analysis (PCA), it appeared that date of ear emergence in perennial ryegrass and characters related to plant vigour in white clover were the main morphological characters separating the reference varieties from the old Dutch grassland populations, and some of the grassland populations from each other. In both species, intrapopulation variation was lower for the reference varieties. Lower heterogeneity within the reference varieties was also found in the AFLP analysis. All common AFLP's observed in old Dutch grasslands could also be found in the reference varieties and nature reserves. Only a small number of low‐frequency alleles found in old Dutch grasslands were absent from the other two groups. However, band frequencies of markers could vary considerably between populations, which may have been caused by selection. Analysis of the AFLP data by PCA distinguished the majority of reference varieties from the old Dutch grasslands, and showed genetic differentiation only between some grasslands. Comparison of old Dutch grasslands with grasslands in nature reserves indicated that basically the same range of genetic variation is covered by the two groups. Our study indicates that the Netherlands harbour a more or less continuous population for major parts of the diversity of perennial ryegrass and white clover. It was concluded that no specific conservation measures are presently needed to maintain genetic diversity of perennial ryegrass and white clover occurring in old Dutch grasslands.
On the ubiquity and phylogeny ofWolbachiain lice
Authors: KYEI‐POKU G. K. , COLWELL D. D. , COGHLIN P. , BENKEL B. , FLOATE K. D.
Published: January 2005

Wolbachiaare intracellular bacteria that occur in an estimated 20% of arthropod species. They are of broad interest because they profoundly affect the reproductive fitness of diverse host taxa. Here we document the apparent ubiquity and diversity ofWolbachiain the insect orders Anoplura (sucking lice) and Mallophaga (chewing lice), by detecting single or multiple infections in each of 25 tested populations of lice, representing 19 species from 15 genera spanning eight taxonomic families. Phylogenetic analyses indicate a high diversity ofWolbachiain lice, as evidenced by the identification of 39 unique strains. Some of these strains are apparently unique to lice, whereas others are similar to strains that infect other insect taxa.Wolbachiaare transmitted from infected females to their offspring via egg cyto‐plasm, such that similar species of lice are predicted to have similar strains ofWolbachia. This predicted pattern is not supported in the current study and may reflect multiple events of recent horizontal transmission between host species. At present, there is no known mechanism that would allow for this latter mode of transmission to and within species of lice.
The pathophysiology of diarrhea
Authors: Sellin Joseph H
Published: January 2005

Abstract Diarrhea is a very common event after transplantation, but its cause may be difficult to identify. The first step in determining the cause in any particular case is an understanding of the etiology of diarrhea in general. Although diarrhea often is categorized into such types as secretory versus osmotic, or electrolyte transport‐related versus motilityrelated, a thorough understanding of the problem requires knowledge of how the paracrine, immune, nervous and endocrine systems react to each other as well as to infection, drugs or other stimuli.
Condition Assessment by Visual Inspection for a Bridge Management System
Authors: Gattulli Vincenzo , Chiaramonte Leonardo
Published: January 2005

Abstract:  The development of a reliable bridge management system (BMS) constitutes a formidable engineering challenge due to both the multiobjective nature of the task and the large amount of information to be considered in formulating the required automated judgments. This article deals with a procedure for bridge condition assessment by visual inspection developed during the planning and preliminary design of the BMS for the public railway networks in Italy. The main modules adopted in the procedure are: bridge inventory, computer‐aided visual inspection, automated defect catalog, and priority‐ranking procedure. The probabilistic models used to calibrate the condition evaluation algorithm are discussed. Different levels of deficiency have been individuated for each class of bridge structure belonging to the managed stock. The procedure allows comparison and relative ranking of deficiency conditions across different types of bridge structures. The results of a visual inspection campaign conducted for a set of bridges with different structural characteristics are reported and evaluated within the framework of the developed BMS.
Differential Quadrature Element Method Analysis of In‐Plane Deflection of Vertically Curved Beam Structures
Authors: Chen Chang‐New
Published: January 2005

Abstract:  The development of the differential quadrature element method (DQEM) in‐plane deflection analysis model of arbitrarily curved beam structures was carried out. The DQEM uses the extended differential quadrature to discretize the differential equation defined on each element, the transition conditions defined on the interelement boundary of two adjacent elements, and the boundary conditions of the beam. Numerical results obtained from solving two structural models using a numerical algorithm are presented. The convergence of the developed DQEM analysis model is efficient.
Work/Care Regimes: Institutions, Culture and Behaviour and the Australian Case
Authors: Pocock Barbara
Published: January 2005

Increasingly around the industrialized world, labour markets rely upon the paid work of women, many of whom have dependents. Such changing patterns of paid work by women — and by men — are located within work/care regimes that are more or less hostile to the needs of paid workers who care for others. This article sets out a model of work/care regimes and locates the Australian case within international and historical contexts. In Australia, the unchanging normative male worker archetype dominates institutions of work and care, while the cultures of motherhood and fatherhood remain stoically resistant to renovation. In the meantime, the behaviour of working women runs ahead of these unchanging cultures and institutions, creating a policy interest in ‘reconciling’ work and care, but a failure to provide it. The reasons for this failure are outlined.
‘I Just Couldn’t Fit It In’: Gender and Unequal Outcomes in Academic Careers
Authors: Probert Belinda
Published: January 2005

This article reports on the findings of two pieces of research that were designed to test and challenge widely accepted theories about the causes of gender inequity in academic employment at the national level, and subsequently in a more detailed case study of one of Australia's largest and most prestigious universities. Both research projects used large‐scale surveys to capture information about levels of human capital, family responsibilities, career preferences, workloads and objective experiences of appointment and promotion. The case study, conducted in 2002, also utilized focus group  discussions  with  particular  groups  of  women  who  seemed,  from the survey data, to be located just under the glass ceiling. The case study research confirmed the earlier national survey research which concluded that discrimination or bias in appointments, promotions and workloads were not significant in explaining men's domination of the senior levels. It also confirmed the significant gender differences in some kinds of human capital (particularly possession of a Ph.D.). But it also pointed to a quite particular explanation for the failure of women to progress to Level D (associate professor/reader) which involved other more general demographic changes — particularly, high rates of separation and divorce, far higher rates of partnering among men than women and the impact of older children's needs.
Loneliness and social adaptation in Brazilian, Canadian, Chinese and Italian children: a multi‐national comparative study
Authors: Chen Xinyin , He Yunfeng , Oliveira Ana Maria De , Coco Alida Lo , Zappulla Carla , Kaspar Violet , Schneider Barry , Valdivia Ibis Alvarez , Tse Hennis Chi‐Hang , DeSouza Amanda
Published: January 2005

Background:  Research on children's loneliness has been conducted mostly in Western, especially North American, cultures. The purpose of the study was to examine relations between loneliness and social adaptation among children and adolescents in four different societies.

Methods:  A total of 2263 children from grade 3 to grade 6, aged 9 to 12 years, in Brazil, Canada, P. R. China, and Southern Italy participated in the study. The participants completed a self‐report measure of loneliness. Information about social behaviors and peer relationships was obtained from peer assessments.

Results:  Multi‐group analyses revealed that the overall patterns of relations among social behaviors, peer relationships and loneliness differed across the samples. Specifically, sociability was positively associated with peer relationships and made negative indirect contributions to loneliness through peer relationships in all four samples. Aggression made significant indirect contributions to the prediction of loneliness in Chinese children, but not in other samples. Shyness‐sensitivity was associated with loneliness directly in Brazilian and Italian children and indirectly through peer relationships in Canadian children, but not associated with loneliness in Chinese children.

Conclusions:  The results suggest that the nature of children's loneliness may be affected by the broad socio‐cultural context.
A new social communication intervention for children with autism: pilot randomised controlled treatment study suggesting effectiveness
Authors: Aldred Catherine , Green Jonathan , Adams Catherine
Published: January 2005

Background:  Psychosocial treatments are the mainstay of management of autism in the UK but there is a notable lack of a systematic evidence base for their effectiveness. Randomised controlled trial (RCT) studies in this area have been rare but are essential because of the developmental heterogeneity of the disorder. We aimed to test a new theoretically based social communication intervention targeting parental communication in a randomised design against routine care alone.

Methods:  The intervention was given in addition to existing care and involved regular monthly therapist contact for 6 months with a further 6 months of 2‐monthly consolidation sessions. It aimed to educate parents and train them in adapted communication tailored to their child's individual competencies. Twenty‐eight children with autism were randomised between this treatment and routine care alone, stratified for age and baseline severity. Outcome was measured at 12 months from commencement of intervention, using standardised instruments.

Results:  All cases studied met full Autism Diagnostic Interview (ADI) criteria for classical autism. Treatment and controls had similar routine care during the study period and there were no study dropouts after treatment had started. The active treatment group showed significant improvement compared with controls on the primary outcome measure – Autism Diagnostic Observation Schedule (ADOS) total score, particularly in reciprocal social interaction – and on secondary measures of expressive language, communicative initiation and parent–child interaction. Suggestive but non‐significant results were found in Vineland Adaptive Behaviour Scales (Communication Sub‐domain) and ADOS stereotyped and restricted behaviour domain.

Conclusions:  A Randomised Treatment Trial design of this kind in classical autism is feasible and acceptable to patients. This pilot study suggests significant additional treatment benefits following a targeted (but relatively non‐intensive) dyadic social communication treatment, when compared with routine care. The study needs replication on larger and independent samples. It should encourage further RCT designs in this area.
Practitioner Review: Stress intervention for parents of children with intellectual disabilities
Authors: Hastings Richard P. , Beck Alexandra
Published: January 2005

Background:  Parents of children with intellectual disabilities are at increased risk for stress and other mental health problems. The purpose of the present review is to consider the evidence base for psychological intervention to remediate stress in these parents.

Methods:  A selective review of interventions designed to reduce stress in parents of children with intellectual disabilities, with a focus on group interventions that incorporate various cognitive behavioural techniques.

Results:  Research evidence suggests that standard service models (e.g., respite care, case management) probably help to reduce parental stress. The strongest evidence base is for cognitive behavioural group interventions, especially for the reduction of stress in mothers. Some data also indicate the potential value of parent‐led support networks.

Conclusions:  More research and clinical development are needed to establish a firmer evidence base for stress interventions with parents of children with intellectual disabilities. There are also a number of potential practical implications of reducing parental stress for maximising the efficacy of general parent training interventions and also behavioural programmes for children's challenging behaviours.
Catalysing Events, Think Tanks and American Foreign Policy Shifts: A Comparative Analysis of the Impacts of Pearl Harbor 1941 and 11 September 2001
Authors: Parmar Inderjeet
Published: January 2005

The American aggression in Iraq and the campaign in Afghanistan resulted from the 11 September 2001 attacks in the US. 9/11 has had a massive, catalysing effect on the American public, press, main political parties and official foreign policy makers. This article assesses the impact of 9/11 in changing US foreign policy and especially in creating a new foreign policy establishment by comparing it to the consequences of an historical military attack on the United States – Pearl Harbor, 7 December 1941. It concludes that there is adequate evidence to suggest that a new bipartisan foreign policy consensus/establishment has emerged.
An analysis of uncertainty in non‐equilibrium and equilibrium geothermobarometry
Authors: ASHWORTH J. R. , SHEPLEV V. S. , KHLESTOV V. V. , ANANYEV V. A.
Published: January 2005

In statistically optimised P–T estimation, the contributions to overall uncertainty from different sources are represented by ellipses. One source, for a diffusion‐controlled reaction at non‐equilibrium, is diffusion modelling of the reaction texture. This modelling is used to estimate ratios, Q, between free‐energy differences, ΔG, of reactions among mineral end‐members, to replace the equilibrium condition ΔG = 0. The associated uncertainty is compared with those already inherent in the equilibrium case (from end‐member data, activity models and mineral compositions). A compact matrix formulation is introduced for activity coefficients, and their partial derivatives governing error propagation. The non‐equilibrium example studied is a corona reaction with the assemblage Grt–Opx–Cpx–Pl–Qtz. Two garnet compositions are used, from opposite sides of the corona. In one of them, affected by post‐reaction Fe, Mg exchange with pyroxene, the problem of reconstructing the original composition is overcome by direct use of ratios between chemical‐potential differences, given by the diffusion modelling. The number of geothermobarometers in the optimisation is limited by near‐degeneracies. Their weightings are affected by strong correlations among Q ratios. Uncertainty from diffusion modelling is not large in comparison with other sources. Overall precision is limited mainly by uncertainties in activity models. Hypothetical equilibrium P–T are also estimated for both garnet compositions. By this approach, departure from equilibrium can be measured, with statistical uncertainties. For the example, the result for difference from equilibrium pressure is 1.2 ± 0.7 kbar.
Two phases of zymogen granule lifetime in mouse pancreas: ghost granules linger after exocytosis of contents
Authors: Thorn Peter , Parker Ian
Published: January 2005

Different cell types show widely divergent mechanisms and kinetics of exocytosis. We investigated these processes in pancreatic acinar cells by using video‐rate 2‐photon microscopy to image entry of extracellular dye into individual zymogen granules undergoing exocytosis. Fluorescence signals display two distinct phases; an initial peak that then decays over several seconds to a prolonged plateau. Several observations suggest that the first component reflects the binding of dye to the granule contents and their subsequent release into the acinar duct. These observations include: the peak/plateau fluorescence ratio differs between different dyes; the initial fluorescence decay mirrors the loss of granule contents as monitored by differential interference contrast microscopy; and the fall in vesicular fluorescence is accompanied by a rise in fluorescence in the adjacent duct lumen. We thus propose the use of extracellular fluorescent probes as a convenient means to monitor the kinetics of loss of proteinaceous content from secretory granules. In pancreatic acinar cells the fusion pore remains open much longer than required to ensure secretion of the granule contents, and instead the persistent empty ‘ghost‐granule’ may act as a conduit to which secondary granules can fuse and release their contents by compound exocytosis.
Control of microvascular oxygen pressures in rat muscles comprised of different fibre types
Authors: McDonough Paul , Behnke Brad J. , Padilla Danielle J. , Musch Timothy I. , Poole David C.
Published: January 2005

In response to an elevated metabolic rate , increased microvascular blood–muscle O2 flux is the product of both augmented O2 delivery and fractional O2 extraction. Whole body and exercising limb measurements demonstrate that and fractional O2 extraction increase as linear and hyperbolic functions, respectively, of . Given the presence of disparate vascular control mechanisms among different muscle fibre types, we tested the hypothesis that, in response to muscle contractions, would be lower and fractional O2 extraction (as assessed via microvascular O2 pressure, P) higher in fast‐ versus slow‐twitch muscles. Radiolabelled microsphere and phosphorescence quenching techniques were used to measure and P, respectively at rest and across the transition to 1 Hz twitch contractions at low (Lo, 2.5 V) and high intensities (Hi, 4.5 V) in rat (n= 20) soleus (Sol, slow‐twitch, type I), mixed gastrocnemius (MG, fast‐twitch, type IIa) and white gastrocnemius (WG, fast‐twitch, type IIb) muscle. At rest and for Lo and Hi (steady‐state values) transitions, P was lower (all P < 0.05) in MG (mmHg: rest, 22.5 ± 1.0; Lo, 15.3 ± 1.3; Hi, 10.2 ± 1.6) and WG (mmHg: rest, 19.0 ± 1.3; Lo, 12.2 ± 1.1; Hi, 9.9 ± 1.1) than in Sol (rest, 33.1 ± 3.2 mmHg; Lo, 19.0 ± 2.3 mmHg; Hi, 18.7 ± 1.8 mmHg), despite lower and in MG and WG under each set of conditions. These data suggest that during submaximal metabolic rates, the relationship between and O2 extraction is dependent on fibre type (at least in the muscles studied herein), such that muscles comprised of fast‐twitch fibres display a greater fractional O2 extraction (i.e. lower P) than their slow‐twitch counterparts. These results also indicate that the greater sustained P in Sol may be important for ensuring high blood–myocyte O2 flux and therefore a greater oxidative contribution to energetic requirements.
The Influence of
CCL3L1
Gene-Containing Segmental Duplications on HIV-1/AIDS Susceptibility
Authors: Gonzalez Enrique , Kulkarni Hemant , Bolivar Hector , Mangano Andrea , Sanchez Racquel , Catano Gabriel , Nibbs Robert J. , Freedman Barry I. , Quinones Marlon P. , Bamshad Michael J. , Murthy Krishna K. , Rovin Brad H. , Bradley William , Clark Robert A. , Anderson Stephanie A. , O'Connell Robert J. , Agan Brian K. , Ahuja Seema S. , Bologna Rosa , Sen Luisa , Dolan Matthew J. , Ahuja Sunil K.
Published: January 2005

Segmental duplications in the human genome are selectively enriched for genes involved in immunity, although the phenotypic consequences for host defense are unknown. We show that there are significant interindividual and interpopulation differences in the copy number of a segmental duplication encompassing the gene encoding CCL3L1 (MIP-1αP), a potent human immunodeficiency virus–1 (HIV-1)–suppressive chemokine and ligand for the HIV coreceptor CCR5. Possession of a
CCL3L1
copy number lower than the population average is associated with markedly enhanced HIV/acquired immunodeficiency syndrome (AIDS) susceptibility. This susceptibility is even greater in individuals who also possess disease-accelerating
CCR5
genotypes. This relationship between
CCL3L1
dose and altered HIV/AIDS susceptibility points to a central role for CCL3L1 in HIV/AIDS pathogenesis and indicates that differences in the dose of immune response genes may constitute a genetic basis for variable responses to infectious diseases.
Disks Around Stars and the Growth of Planetary Systems
Authors: Greaves Jane S.
Published: January 2005

Circumstellar disks play a vital evolutionary role, providing a way to move gas inward and onto a young star. The outward transfer of angular momentum allows the star to contract without breaking up, and the remnant disk of gas and particles is the reservoir for forming planets. High-resolution spectroscopy is uncovering planetary dynamics and motion within the remnant disk, and imaging at infrared to millimeter wavelengths resolves disk structure over billions of years of evolution. Most stars are born with a disk, and models of planet formation need to form such bodies from the disk material within the disk's 10-million-year life-span.
Expanded Repeat in Canine Epilepsy
Authors: Lohi Hannes , Young Edwin J. , Fitzmaurice Susan N. , Rusbridge Clare , Chan Elayne M. , Vervoort Mike , Turnbull Julie , Zhao Xiao-Chu , Ianzano Leonarda , Paterson Andrew D. , Sutter Nathan B. , Ostrander Elaine A. , André Catherine , Shelton G. Diane , Ackerley Cameron A. , Scherer Stephen W. , Minassian Berge A.
Published: January 2005

Epilepsy afflicts 1% of humans and 5% of dogs. We report a canine epilepsy mutation and evidence for the existence of repeat-expansion disease outside humans. A canid-specific unstable dodecamer repeat in the
Epm2b
(
Nhlrc1
) gene recurrently expands, causing a fatal epilepsy and contributing to the high incidence of canine epilepsy. Tracing the repeat origins revealed two successive events, starting 50 million years ago, unique to canid evolution. A genetic test, presented here, will allow carrier and presymptomatic diagnosis and disease eradication. Clinicopathologic characterization establishes affected animals as a model for Lafora disease, the most severe teenage-onset human epilepsy.
Electron Tunneling Through Organic Molecules in Frozen Glasses
Authors: Wenger Oliver S. , Leigh Brian S. , Villahermosa Randy M. , Gray Harry B. , Winkler Jay R.
Published: January 2005

Reaction rates extracted from measurements of donor luminescence quenching by randomly dispersed electron acceptors reveal an exponential decay constant of 1.23 per angstrom for electron tunneling through a frozen toluene glass (with a barrier to tunneling of 1.4 electron volts). The decay constant is 1.62 per angstrom (the barrier, 2.6 electron volts) in a frozen 2-methyl-tetrahydrofuran glass. Comparison to decay constants for tunneling across covalently linked xylyl (0.76 per angstrom) and alkyl (1.0 per angstrom) bridges leads to the conclusion that tunneling between solvent molecules separated by ∼2 angstroms (van der Waals contact) is 20 to 50 times slower than tunneling through a comparable length of a covalently bonded bridge. Our results provide experimental confirmation that covalently bonded pathways can facilitate electron flow through folded polypeptide structures.
Spindle Multipolarity Is Prevented by Centrosomal Clustering
Authors: Quintyne Nicholas J. , Reing Janet E. , Hoffelder Diane R. , Gollin Susanne M. , Saunders William S.
Published: January 2005

Most tumor cells are characterized by increased genomic instability and chromosome segregational defects, often associated with hyperamplification of the centrosome and the formation of multipolar spindles. However, extra centrosomes do not always lead to multipolarity. Here, we describe a process of centrosomal clustering that prevented the formation of multipolar spindles in noncancer cells. Noncancer cells needed to overcome this clustering mechanism to allow multipolar spindles to form at a high frequency. The microtubule motor cytoplasmic dynein was a critical part of this coalescing machinery, and in some tumor cells overexpression of the spindle protein NuMA interfered with dynein localization, promoting multipolarity.
Black Hole Accretion
Authors: Narayan Ramesh , Quataert Eliot
Published: January 2005

Black holes are most often detected by the radiation produced when they gravitationally pull in surrounding gas, in a process called accretion. The efficiency with which the hot gas radiates its thermal energy strongly influences the geometry and dynamics of the accretion flow. Both radiatively efficient thin disks and radiatively inefficient thick disks are observed. When the accreting gas gets close to the central black hole, the radiation it produces becomes sensitive to the spin of the hole and the presence of an event horizon. Analysis of the luminosities and spectra of accreting black holes has yielded tantalizing evidence for both rotating holes and event horizons. Numerical simulations imply that the relativistic jets often seen from accreting black holes may be powered in part by the spin of the hole.
Identification and Partial Characterization of the Nonribosomal Peptide Synthetase Gene Responsible for Cereulide Production in Emetic
Bacillus cereus
Authors: Ehling-Schulz Monika , Vukov Natasa , Schulz Anja , Shaheen Ranad , Andersson Maria , Märtlbauer Erwin , Scherer Siegfried
Published: January 2005

Cereulide, a depsipeptide structurally related to valinomycin, is responsible for the emetic type of gastrointestinal disease caused by
Bacillus cereus
. Due to its chemical structure, (
d
-
O
-Leu-
d
-Ala-
l
-
O
-Val-
l
-Val)
3
, cereulide might be synthesized nonribosomally. Therefore, degenerate PCR primers targeted to conserved sequence motifs of known nonribosomal peptide synthetase (NRPS) genes were used to amplify gene fragments from a cereulide-producing
B. cereus
strain. Sequence analysis of one of the amplicons revealed a DNA fragment whose putative gene product showed significant homology to valine activation NRPS modules. The sequences of the flanking regions of this DNA fragment revealed a complete module that is predicted to activate valine, as well as a putative carboxyl-terminal thioesterase domain of the NRPS gene. Disruption of the peptide synthetase gene by insertion of a kanamycin cassette through homologous recombination produced cereulide-deficient mutants. The valine-activating module was highly conserved when sequences from nine emetic
B. cereus
strains isolated from diverse geographical locations were compared. Primers were designed based on the NRPS sequence, and the resulting PCR assay, targeting the
ces
gene, was tested by using a panel of 143
B. cereus
group strains and 40 strains of other bacterial species showing PCR bands specific for only the cereulide-producing
B. cereus
strains.
Activity and Diversity of Methanogens in a Petroleum Hydrocarbon-Contaminated Aquifer
Authors: Kleikemper Jutta , Pombo Silvina A. , Schroth Martin H. , Sigler William V. , Pesaro Manuel , Zeyer Josef
Published: January 2005

Methanogenic activity was investigated in a petroleum hydrocarbon-contaminated aquifer by using a series of four push-pull tests with acetate, formate, H
2
plus CO
2
, or methanol to target different groups of methanogenic
Archaea
. Furthermore, the community composition of methanogens in water and aquifer material was explored by molecular analyses, i.e., fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes amplified with the
Archaea
-specific primer set ARCH915 and UNI-b-rev, and sequencing of DNA from dominant DGGE bands. Molecular analyses were subsequently compared with push-pull test data. Methane was produced in all tests except for a separate test where 2-bromoethanesulfonate, a specific inhibitor of methanogens, was added. Substrate consumption rates were 0.11 mM day
−1
for methanol, 0.38 mM day
−1
for acetate, 0.90 mM day
−1
for H
2
, and 1.85 mM day
−1
for formate. Substrate consumption and CH
4
production during all tests suggested that at least three different physiologic types of methanogens were present: H
2
plus CO
2
or formate, acetate, and methanol utilizers. The presence of 15 to 20 bands in DGGE profiles indicated a diverse archaeal population. High H
2
and formate consumption rates agreed with a high diversity of methanogenic
Archaea
consuming these substrates (16S rRNA gene sequences related to several members of the
Methanomicrobiaceae
) and the detection of
Methanomicrobiaceae
by using FISH (1.4% of total DAPI [4′,6-diamidino-2-phenylindole]-stained microorganisms in one water sample; probe MG1200). Considerable acetate consumption agreed with the presence of sequences related to the obligate acetate degrader
Methanosaeata concilii
and the detection of this species by FISH (5 to 22% of total microorganisms; probe Rotcl1). The results suggest that both aceticlastic and CO
2
-type substrate-consuming methanogens are likely involved in the terminal step of hydrocarbon degradation, while methanogenesis from methanol plays a minor role. DGGE profiles further indicate similar archaeal community compositions in water and aquifer material. The combination of hydrogeological and molecular methods employed in this study provide improved information on the community and the potential activity of methanogens in a petroleum hydrocarbon-contaminated aquifer.
Cyt1A of
Bacillus thuringiensis
Delays Evolution of Resistance to Cry11A in the Mosquito
Culex quinquefasciatus
Authors: Wirth Margaret C. , Park Hyun-Woo , Walton William E. , Federici Brian A.
Published: January 2005

Insecticides based on
Bacillus thuringiensis
subsp.
israelensis
have been used for mosquito and blackfly control for more than 20 years, yet no resistance to this bacterium has been reported. Moreover, in contrast to
B. thuringiensis
subspecies toxic to coleopteran or lepidopteran larvae, only low levels of resistance to
B. thuringiensis
subsp.
israelensis
have been obtained in laboratory experiments where mosquito larvae were placed under heavy selection pressure for more than 30 generations. Selection of
Culex quinquefasciatus
with mutants of
B. thuringiensis
subsp.
israelensis
that contained different combinations of its Cry proteins and Cyt1Aa suggested that the latter protein delayed resistance. This hypothesis, however, has not been tested experimentally. Here we report experiments in which separate
C. quinquefasciatus
populations were selected for 20 generations to recombinant strains of
B. thuringiensis
that produced either Cyt1Aa, Cry11Aa, or a 1:3 mixture of these strains. At the end of selection, the resistance ratio was 1,237 in the Cry11Aa-selected population and 242 in the Cyt1Aa-selected population. The resistance ratio, however, was only 8 in the population selected with the 1:3 ratio of Cyt1Aa and Cry11Aa strains. When the resistant mosquito strain developed by selection to the Cyt1Aa-Cry11Aa combination was assayed against Cry11Aa after 48 generations, resistance to this protein was 9.3-fold. This indicates that in the presence of Cyt1Aa, resistance to Cry11Aa evolved, but at a much lower rate than when Cyt1Aa was absent. These results indicate that Cyt1Aa is the principal factor responsible for delaying the evolution and expression of resistance to mosquitocidal Cry proteins.
Enantioselective Synthesis ofS-Equol from Dihydrodaidzein by a Newly Isolated Anaerobic Human Intestinal Bacterium
Authors: Wang Xiu-Ling , Hur Hor-Gil , Lee Je Hyeon , Kim Ki Tae , Kim Su-Il
Published: January 2005

A newly isolated rod-shaped, gram-negative anaerobic bacterium from human feces, named Julong 732, was found to be capable of metabolizing the isoflavone dihydrodaidzein toS-equol under anaerobic conditions. The metabolite, equol, was identified by using electron impact ionization mass spectrometry,1H and13C nuclear magnetic resonance spectroscopy, and UV spectral analyses. However, strain Julong 732 was not able to produce equol from daidzein, and tetrahydrodaidzein and dehydroequol, which are most likely intermediates in the anaerobic metabolism of dihydrodaidzein, were not detected in bacterial culture medium containing dihydrodaidzein. Chiral stationary-phase high-performance liquid chromatography eluted only one metabolite,S-equol, which was produced from a bacterial culture containing a racemic mixture of dihydrodaidzein. Strain Julong 732 did not show racemase activity to transformR-equol toS-equol and vice versa. Its full 16S rRNA gene sequence (1,429 bp) had 92.8% similarity to that ofEggerthella hongkongenisHKU10. This is the first report of a single bacterium capable of converting a racemic mixture of dihydrodaidzein to enantiomeric pureS-equol.
Mercury Adaptation among Bacteria from a Deep-Sea Hydrothermal Vent
Authors: Vetriani Costantino , Chew Yein S. , Miller Susan M. , Yagi Jane , Coombs Jonna , Lutz Richard A. , Barkay Tamar
Published: January 2005

Since deep-sea hydrothermal vent fluids are enriched with toxic metals, it was hypothesized that (i) the biota in the vicinity of a vent is adapted to life in the presence of toxic metals and (ii) metal toxicity is modulated by the steep physical-chemical gradients that occur when anoxic, hot fluids are mixed with cold oxygenated seawater. We collected bacterial biomass at different distances from a diffuse flow vent at 9°N on the East Pacific Rise and tested these hypotheses by examining the effect of mercuric mercury [Hg(II)] on vent bacteria. Four of six moderate thermophiles, most of which were vent isolates belonging to the genus
Alcanivorax
, and six of eight mesophiles from the vent plume were resistant to >10 μM Hg(II) and reduced it to elemental mercury [Hg(0)]. However, four psychrophiles that were isolated from a nearby inactive sulfide structure were Hg(II) sensitive. A neighbor-joining tree constructed from the deduced amino acids of a PCR-amplified fragment of
merA
, the gene encoding the mercuric reductase (MR), showed that sequences obtained from the vent moderate thermophiles formed a unique cluster (bootstrap value, 100) in the MR phylogenetic tree, which expanded the known diversity of this locus. The temperature optimum for Hg(II) reduction by resting cells and MR activity in crude cell extracts of a vent moderate thermophile corresponded to its optimal growth temperature, 45°C. However, the optimal temperature for activity of the MR encoded by transposon Tn
501
was found to be 55 to 65°C, suggesting that, in spite of its original isolation from a mesophile, this MR is a thermophilic enzyme that may represent a relic of early evolution in high-temperature environments. Results showing that there is enrichment of Hg(II) resistance among vent bacteria suggest that these bacteria have an ecological role in mercury detoxification in the vent environment and, together with the thermophilicity of MR, point to geothermal environments as a likely niche for the evolution of bacterial mercury resistance.
Redox Interactions betweenSaccharomyces cerevisiaeandSaccharomyces uvarumin Mixed Culture under Enological Conditions
Authors: Cheraiti Naoufel , Guezenec Stéphane , Salmon Jean-Michel
Published: January 2005

Wine yeast starters that contain a mixture of different industrial yeasts with various properties may soon be introduced to the market. The mechanisms underlying the interactions between the different strains in the starter during alcoholic fermentation have never been investigated. We identified and investigated some of these interactions in a mixed culture containing two yeast strains grown under enological conditions. The inoculum contained the same amount (each) of a strain ofSaccharomyces cerevisiaeand a natural hybrid strain ofS. cerevisiaeandSaccharomyces uvarum. We identified interactions that affected biomass, by-product formation, and fermentation kinetics, and compared the redox ratios of monocultures of each strain with that of the mixed culture. The redox status of the mixed culture differed from that of the two monocultures, showing that the interactions between the yeast strains involved the diffusion of metabolite(s) within the mixed culture. Since acetaldehyde is a potential effector of fermentation, we investigated the kinetics of acetaldehyde production by the different cultures. TheS. cerevisiae-S. uvarumhybrid strain produced large amounts of acetaldehyde for which theS. cerevisiaestrain acted as a receiving strain in the mixed culture. Since yeast response to acetaldehyde involves the same mechanisms that participate in the response to other forms of stress, the acetaldehyde exchange between the two strains could play an important role in inhibiting some yeast strains and allowing the growth of others. Such interactions could be of particular importance in understanding the ecology of the colonization of complex fermentation media byS. cerevisiae.
Clinical and Environmental Isolates of
Legionella pneumophila
Serogroup 1 Cannot Be Distinguished by Sequence Analysis of Two Surface Protein Genes and Three Housekeeping Genes
Authors: Aurell Helena , Farge Pierre , Meugnier Hélène , Gouy Manolo , Forey Françoise , Lina Gérard , Vandenesch François , Etienne Jerome , Jarraud Sophie
Published: January 2005

We used gene sequencing to determine whether clinical (sporadic, epidemic, and endemic) and environmental isolates of
Legionella pneumophila
serogroup (sg) 1 belong to specific lineages. A total of 178 clinical and environmental
L. pneumophila
sg 1 isolates, defined by pulsed-field gel electrophoresis and epidemiological data as sporadic, epidemic, or endemic, were analyzed for polymorphisms in five gene fragments. The fragments belonged to three housekeeping genes (coding for aconitase [
acn
], aspartate-β-semialdehyde dehydrogenase [
asd
], and RNA polymerase β subunit [
rpoB
]) and two surface protein genes (coding for the macrophage infectivity potentiator [
mip
] and the major outer membrane protein [
mompS
]). The phylogenetic tree inferred from sequence polymorphisms of the five genes identified two large clusters, one consisting of 133 poorly differentiated strains and containing two smaller clusters (10 and 2 strains) unrelated to each other and the other consisting of 42 strains. Clinical and environmental isolates could not be distinguished on this basis, and no link between genetic background and epidemiological type was found, suggesting that other factors are responsible for differences in pathogenicity.
Genetic Diversity and Horizontal Transfer of Genes Involved in Oxidation of Reduced Phosphorus Compounds by
Alcaligenes faecalis
WM2072
Authors: Wilson Marlena M. , Metcalf William W.
Published: January 2005

Enrichment was performed to isolate organisms that could utilize reduced phosphorus compounds as their sole phosphorus sources. One isolate that grew well with either hypophosphite or phosphite was identified by 16S rRNA gene analysis as a strain of
Alcaligenes faecalis
. The genes required for oxidation of hypophosphite and phosphite by this organism were identified by using transposon mutagenesis and include homologs of the
ptxD
and
htxA
genes of
Pseudomonas stutzeri
WM88, which encode an NAD-dependent phosphite dehydrogenase (PtxD) and 2-oxoglutarate-dependent hypophosphite dioxygenase (HtxA). This organism also has the
htxB
,
htxC
, and
htxD
genes that comprise an ABC-type transporter, presumably for hypophosphite and phosphite transport. The role of these genes in reduced phosphorus metabolism was confirmed by analyzing the growth of mutants in which these genes were deleted. Sequencing data showed that
htxA
,
htxB
,
htxC
, and
htxD
are virtually identical to their homologs in
P. stutzeri
at the DNA level, indicating that horizontal gene transfer occurred. However,
A. faecalis ptxD
is very different from its
P. stutzeri
homolog and represents a new
ptxD
lineage. Therefore, this gene has ancient evolutionary roots in bacteria. These data suggest that there is strong evolutionary selection for the ability of microorganisms to oxidize hypophosphite and phosphite.