bluuebunny/crossref_metadata_2025 huggingface dataset:
Setting Things Right? Swedish Upper Secondary School Reform in a 40‐Year Perspective
Authors: LUNDAHL LISBETH , ARREMAN INGER ERIXON , LUNDSTRÖM ULF , RÖNNBERG LINDA
Published: February 2010

This article analyses reforms addressing and affecting the curriculum and organisation of Swedish upper secondary education over 40 years, up to an initiative by the present non‐socialist government. The aim is to analyse the current reform of upper secondary education and relate it to previous reforms during a 40‐year period in terms of continuity and breaks, mainly with regard to major functions of the reforms and the structuring and control of educational contents. Aiming to create a sharper division of students into three separate streams (academic and vocational education, and apprenticeship training), the reform constitutes a major break with the previously dominant trend towards greater integration. It is argued that it will result in a restriction and reformulation of the knowledge which is regarded as desirable. Similar moves are evident in relation to teacher education, which, if enacted, would involve moving from a model of high flexibility and a common core of knowledge to substantially stronger divisions between contents and programmes.
The humanitarians' tragedy: escapable and inescapable cruelties
Authors: De Waal Alex
Published: February 2010

Paradoxically, elements of cruelty are intrinsic to the humanitarian enterprise.1 This paper focuses on some of these. Escapable cruelties arise from technical failings, but the gradual professionalisation of the field and improvements in relief technologies mean that they have been significantly reduced in comparison to earlier eras. Other cruelties arise from clashes among rights, and the tensions inherent in trying to promote humanity amid the horrors of war. These are inescapable and constitute the ‘humanitarians' tragedy’. Among them is the individual cruelty of failing to do good at the margin: a clash between the individual's impulses and ideals and the constraints of operating in constrained circumstances. This is a version of triage. In addition, there is the cruelty of compromising dearly‐held principles when faced with other competing or overriding demands. There is also the cruelty whereby humanitarians feed victims' dreams that there is an alternative reality, which in fact cannot be attained.
The humanitarian arena in Angola, 1975–2008
Authors: Hilhorst Dorothea , Serrano Maliana
Published: February 2010

In conflict and post‐conflict societies, service delivery is complex both in terms of actors and of the kinds of services provided. The dominant framework of humanitarian space, with its strong focus on international humanitarian assistance and on humanitarian principles, does not fully capture the dynamics and process of service delivery. This paper proposes an alternative analytical framework that depicts humanitarian space as an arena where aid is negotiated and its outcomes shaped by the interaction of various social actors. It reviews the history of service delivery in Angola and shows that during different conflict and post‐conflict phases, a range of actors and service types that fall outside of those labelled as humanitarian were essential in addressing local needs. Stepping away from normative expectations of what happens during humanitarian crises reveals how service delivery gets shaped in everyday practice and provides an alternative understanding of crises response.
Ethical dilemmas? UK immigration, Legal Aid funding reform and caseworkers (Respond to this article at http://www.therai.org.uk/at/debate)
Authors: James Deborah , Killick Evan
Published: February 2010

The article considers the kinds of responsibilities anthropologists might have when working on immigration and asylum matters, particularly in the light of recent ‘reforms’ to the funding of legal aid in the UK. The article focuses on a single case study in its context, exploring an interaction between an immigrant applicant and a lawyer/case worker in a not‐for‐profit Law Centre. The paper shows how case workers find themselves caught in the middle, squeezed between increasing financial pressures and their ethical obligation to their clients. In their everyday work they are faced with the contradictory imperatives of giving sympathy and advice to genuinely deserving cases on the one hand while being required to check up on opportunist and possibly deceitful clients on the other. In the context of ‘reform’, they are increasingly encouraged to prejudge the probable outcomes of cases by reference to ‘value for money’. These effects, we argue, have severe consequences given the adversarial nature of the UK's system of law. As anthropologists, our aim was to investigate the day‐to‐day realities of case worker/client interactions, to enable both ourselves and legal practitioners, in conversation, to reflect on our own and each others' interpretations of the situation, and to place these in the public domain.
Research Productivity and Social Capital in Australian Higher Education
Authors: Salaran Mohammad
Published: February 2010

This study investigates the role of social capital in raising research productivity in academic institutions. Social capital as a strategic resource embedded in social relationships can be utilised towards decreasing pressures from external environmental conditions, such as the global financial crisis. A survey was sent to academic staff in five universities in Victoria, to collect data regarding their frequency of communications and research productivity. The findings indicated that there is a significant and positive correlation between social interactions and research productivity. Regression analysis demonstrated that social interactions as an independent variable predict research productivity of academics.
Developing a contemporary conceptualization for consumer sciences in higher education in the UK
Authors: Bailey Sue
Published: February 2010

Consumer sciences and consumer studies as a recent interdisciplinary degree area in higher education in the UK has had limited published research either on the subject heritage or its disciplinary identity. Since the major subject review was undertaken by the Council for National Academic Awards 17 years ago, the research investigation aimed to study how consumer studies and home economics had moved to consumer sciences and consumer studies. The research has therefore involved a survey over a 15‐year period of development and changes of institutions and degrees and a content analysis of programme outlines and national benchmarking to reveal changing trends in how the subject has been conceptualized. The comparison used data from 1992, 1999, 2003 and 2007 to map degree programme and institutional changes. External and internal political and economic factors influenced subject growth, decline and development. It was found that the number of degree programme titles had remained relatively stable, with still a balance between BA and BSc degrees but that this disguised many changes in institutions and degree titles.

The content analysis of trends was undertaken, comparing 1992, 1999, 2003 and 2007. Subject benchmarking statements introduced in 2002, currently being revised in 2009, were compared with programme content themes in 2003 and 2007. The content analysis showed that the overall approach or principles, areas of study, context, perspectives and processes for degree programmes at the undergraduate level had developed noticeably over the last 15 years and had been clarified by benchmarking guidelines. Themes of behavioural change, consumer ethics, consumer services, skills and education, sustainability and well‐being had developed with applied contexts depending on programme orientation.

A model has been proposed to illustrate the current conceptualization of the subject in the UK at degree level, and Chenoweth's definition of consumer sciences and consumer studies has been redefined for the UK. It is recommended that there should be more theoretical reflection on the interpretation and development of the subject.
Procedure to Perform a Validated Incremental Hole Drilling Measurement: Application to Shot Peening Residual Stresses
Authors: Valentini E. , Beghini M. , Bertini L. , Santus C. , Benedetti M.
Published: February 2010

Abstract:  The paper describes a test rig designed to check and assess the accuracy of the incremental hole drilling (IHD) method. An external load produces a controlled linearly through thickness variable uniaxial stress field (reference bending stress), known with good accuracy, that can be applied and removed at each hole increment. After the separation between the bending relaxed strain from the residual stress relaxed strain, it is possible to reproduce the bending stress distribution in order to have complete confidence of the residual stress measurement. The bending verification of the IHD method was already proposed by other investigators before, but residual stress measurements were then performed on independent configurations. The proposed testing procedure gives a ‘real time’ verification of the residual stress measurement. Any experimental malfunctioning due to the operator inexperience, or any error during the stress calculation from the relaxed strain would produce an evident difference between the expected reference bending stress and the IHD bending stress output. Moreover, the reference bending stress helped for understanding that the not perfect hole cylindrical shape causes an underestimate of the predicted stress near the surface. A zero depth offset correction was proposed. This correction was tested on the reference bending stress, and then applied to the residual stress prediction. Three shot peening residual stresses IHD measurements were successfully validated by means of the bending stress; moreover, they were in good agreement with independent X‐ray diffraction measures also proposed in the paper.
Genetic variability of Old Portuguese bread wheat cultivars assayed by IRAP and REMAP markers
Authors: Carvalho A. , Guedes‐Pinto H. , Martins‐Lopes P. , Lima‐Brito J.
Published: February 2010

Retrotransposons (RTNs) constitute informative molecular markers for plant species as a result of their ability of integrating into a multitude of loci throughout the genome and thereby generating insertional polymorphisms between individuals. Inter‐retrotransposon amplified polymorphisms (IRAPs) and the retrotransposon‐microsatellite amplified polymorphisms (REMAPs) are marker systems based on long terminal repeats (LTRs) RTNs, developed for plants, that have been widely used for evolution, genetic diversity, DNA fingerprinting of cultivars and varieties, genetic mapping linkage and for detection of genetic rearrangements induced by polyploidisation. In the present study, we aimed to analyse the genetic variability among 48 Old Portuguese bread wheat cultivars using both IRAP and REMAP markers. Five IRAP and six REMAP primer combinations were used. IRAP produced 103 polymorphic fragments in a total of 113 bands. On average, 22.6 bands were amplified per IRAP primer combination. The bands ranged in size from 250 to 5000 bp. The REMAP primer combinations allowed the amplification of 53 bands, 51 of them polymorphic. An average of 8.8 REMAP bands was scored per primer combination. The REMAP bands ranged from 250 to 3000 bp.

Both marker systems presented high percentages of polymorphism. However, IRAP markers were suitable for detecting genetic variability at the individual level and did not differentiate higher taxa. The REMAP maker system allowed the clustering by botanical variety and identified most of the homonym bread wheat cultivars.
Mitochondrial proline oxidation is affected by hyperosmotic stress in durum wheat seedlings
Authors: Soccio M. , Laus M.N. , Spera G.P. , Trono D. , Pompa M. , Flagella Z. , Pastore D.
Published: February 2010

The important role of plant mitochondria in the adaptation to environmental stresses at subcellular level has recently emerged. In particular, an important mitochondrial mechanism involved in the resistance to environmental stresses is the inhibition of proline oxidation. In order to study this physiological mechanism, we used both washed and purified durum wheat (Triticum durum) mitochondria (DWM) isolated from early seedlings germinated in two different NaCl solutions leading to either moderate or severe damage to growth. To assess the contribution of the osmotic component of stress, a parallel investigation was performed using hyperosmotic mannitol solutions.

Comparison of the oxygen uptake rate in the course of proline oxidation, with that of the malate plus glutamate substrate pair and that of succinate showed that an early inhibition of proline oxidation occurs under stress. The drop of the proline‐dependent oxygen uptake rate was as a result of a heavy inhibition of proline dehydrogenase (ProDH); on the other hand, malate plus glutamate‐dependent and succinate‐dependent oxidations were less inhibited, being the maintenance of oxygen uptake rate not dependent on alternative oxidase (AOX) pathway; in fact, DWM‐AOX activity did not show any increase under our experimental stress conditions. The selective inhibition of proline oxidation should be considered a mitochondrial adaptation to stress rather than damage to mitochondrial oxidative properties. This result was achieved by means of a novel approach based on the comparison between oxygen uptake rates of washed and purified organelles.
School District Democracy: School Board Voting and School Performance
Authors: WEBBER DAVID J.
Published: February 2010

In line with social capital theory, citizen involvement in local education policy making should affect education performance. Specifically, because voting turnout and candidate competition in school district elections are accountability mechanisms and reflections of a district's social capital, these characteristics of school board elections should affect how schools perform. Using official Missouri election records and school district data, this article examines the effect of district social capital (i.e., voting turnout and candidate competition), demographics, and school resources on school performance (i.e., standardized test scores and graduation rates). Mixed support is found for social capital theory, with voting turnout significantly affecting standardized test scores, though not graduation rates, and candidate competition influencing graduation rates, though in an unexpected direction. This study expands our understanding of the factors affecting school performance and informs the discussion of education reform.

En línea con la teoría del capital social, la participación de los ciudadanos en la hechura de las políticas de educación local debería afectar el rendimiento escolar. Específicamente, porque la participación en la votación y el grado de competencia entre candidatos en las elecciones en los distritos escolares son mecanismos de rendición de cuentas y un reflejo del capital social del distrito, estas características de las elecciones del consejo escolar deberían afectar el desempeño de las escuelas. Utilizando registros oficiales de las elecciones en Missouri e información de los distritos escolares, este artículo examina el efecto del capital social del distrito (i.e., participación en la votación y el grado de competencia entre candidatos), la demografía, y los recursos escolares en el rendimiento escolar (i.e., los resultados estandarizados de las pruebas y las tasas de graduación). Se encuentra un apoyo mixto para la teoría del capital social donde la participación en la votación afecta considerablemente los resultados estandarizados de las pruebas, aunque no a las tasas de graduación, y en una dirección inesperada, el grado de competencia entre candidatos influye a las tasas de graduación. Este articulo amplia nuestro entendimiento de los factores que afectan el rendimiento escolar y fortalece la discusión sobre la reforma educativa.
Adenosine A1 receptors and vascular reactivity
Authors: Wang Y. , Yang J. N. , Arner A. , Boels P. J. M. , Fredholm B. B.
Published: February 2010

Aim:  Blood pressure is higher in A1 receptor knock‐out (A1R−/−) mice than in wild type litter mates (A1R+/+) and we have examined if this could be related to altered vascular functions.

Methods:  Contraction of aortic rings and mesenteric arteries were examined. To examine if the adenosine A1 receptor‐mediated contraction of aortic muscle was functionally important we examined pulse pressure (PP) and augmentation index (AIX) using a sensor that allows measurements of rapid pressure transients.

Results:  Contraction of aortic rings to phenylephrine and relaxation to acetylcholine were similar between genotypes. The non‐selective adenosine receptor agonist N‐ethyl carboxamido adenosine (NECA) enhanced the contractile response, and this was eliminated in aortas from A1R−/− mice. However, in mesenteric arteries no contractile response was seen and adenosine‐mediated relaxation was identical between studied genotypes. A2B adenosine receptors, rather than A2A receptors, may be mainly responsible for the vasorelaxation induced by adenosine analogues in the examined mouse vessels. PP was higher in A1R−/− mice, but variability was unaltered. AIX was not different between genotypes, but the NECA‐induced fall was larger in A1R−/− mice.

Conclusions:  The role of adenosine A1 receptors in regulating vessel tone differs between blood vessels. Furthermore, contractile effects on isolated vessels cannot explain the blood pressure in A1 knock‐out mice. The A1 receptor modulation of blood pressure is therefore mainly related to extravascular factors.
Worldwide invasion by the little fire ant: routes of introduction and eco‐evolutionary pathways
Authors: Foucaud Julien , Orivel Jérôme , Loiseau Anne , Delabie Jacques H. C. , Jourdan Hervé , Konghouleux Djoël , Vonshak Merav , Tindo Maurice , Mercier Jean‐Luc , Fresneau Dominique , Mikissa Jean‐Bruno , McGlynn Terry , Mikheyev Alexander S. , Oettler Jan , Estoup Arnaud
Published: February 2010

Biological invasions are generally thought to occur after human aided migration to a new range. However, human activities prior to migration may also play a role. We studied here the evolutionary genetics of introduced populations of the invasive ant Wasmannia auropunctata at a worldwide scale. Using microsatellite markers, we reconstructed the main routes of introduction of the species. We found three main routes of introduction, each of them strongly associated to human history and trading routes. We also demonstrate the overwhelming occurrence of male and female clonality in introduced populations of W. auropunctata, and suggest that this particular reproduction system is under selection in human‐modified habitats. Together with previous researches focused on native populations, our results suggest that invasive clonal populations may have evolved within human modified habitats in the native range, and spread further from there. The evolutionarily most parsimonious scenario for the emergence of invasive populations of the little fire ant might thus be a two‐step process. The W. auropunctata case illustrates the central role of humans in biological change, not only due to changes in migration patterns, but also in selective pressures over species.
Influenza Virus Vaccine Based on the Conserved Hemagglutinin Stalk Domain
Authors: Steel John , Lowen Anice C. , Wang Taia T. , Yondola Mark , Gao Qinshan , Haye Kester , García-Sastre Adolfo , Palese Peter
Published: February 2010

Although highly effective in the general population when well matched to circulating influenza virus strains, current influenza vaccines are limited in their utility due to the narrow breadth of protection they provide. The strain specificity of vaccines presently in use mirrors the exquisite specificity of the neutralizing antibodies that they induce, that is, antibodies which bind to the highly variable globular head domain of hemagglutinin (HA). Herein, we describe the construction of a novel immunogen comprising the conserved influenza HA stalk domain and lacking the globular head. Vaccination of mice with this headless HA construct elicited immune sera with broader reactivity than those obtained from mice immunized with a full-length HA. Furthermore, the headless HA vaccine provided full protection against death and partial protection against disease following lethal viral challenge. Our results suggest that the response induced by headless HA vaccines is sufficiently potent to warrant their further development toward a universal influenza virus vaccine.

IMPORTANCE
Current influenza vaccines are effective against only a narrow range of influenza virus strains. It is for this reason that new vaccines must be generated and administered each year. We now report progress toward the goal of an influenza virus vaccine which would protect against multiple strains. Our approach is based on presentation to the host immune system of a region of the influenza virus—called a “headless hemagglutinin” (headless HA)—which is similar among a multitude of diverse strains. We show that vaccination of mice with a headless HA confers protection to these animals against a lethal influenza virus challenge, thereby demonstrating the viability of the approach. Through further development and testing, we predict that a single immunization with a headless HA vaccine will offer effective protection through several influenza epidemics.
Host–Guest interaction of pesticide bifenox with cyclodextrin molecules. An electrochemical study
Authors: Hromadová Magdaléna , Sokolová Romana , Pospíšil Lubomír , Lachmanová Štěpánka , Fanelli Nicolangelo , Giannarelli Stefania
Published: February 2010

The reduction of nitroaromatic compound bifenox (methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate) was studied in aprotic solvents in the absence or presence of cyclodextrin (CD) molecules of different cavity sizes. βCD and γCD form complexes with bifenox in DMSO with the complex formation constants (5 ± 2) × 102 M–1 [βCD–bifenox] and (3 ± 1) × 102 M–1 [γCD–bifenox], respectively. Bifenox yields a relatively stable anion radical in dimethyl sulfoxide, which is further reduced at more negative potentials by an overall addition of three electrons and four protons to the corresponding phenylhydroxylamine. In the presence of βCD the first reduction wave of bifenox becomes irreversible, it is shifted towards more positive potentials and the uptake of more than one electron is observed (up to four electrons during the exhaustive electrolysis). The first reduction wave of bifenox is not affected by the addition of glucose confirming that a simple availability of protons from the OH groups is not the main factor in further transformation of anion radical in the presence of βCD. The complex formation with βCD facilitates the protonation and additionally protects the molecule from disintegration into 2,4-dichlorophenol. A yield of 2,4-dichlorophenol decreases in the order βCD, γCD and αCD, respectively.
Sequence analysis of two deletion mutants in the hisC gene of Salmonella typhimurium
Authors: Albritton W. L. , Chui L.
Published: February 2010

Limited sequencing of the terminal region of the hisC gene in two deletion mutants involving the hisC gene of Salmonella typhimurium was carried out after polymerase chain reaction amplification of the appropriate region, using oligonucleotide primers selected from the published sequence of the histidine operon from this organism. his2648 was shown to have a 34 base pair deletion in the terminal region of the hisC gene between the P2 promoter and the Shine–Delgamo sequence of the hisB gene. hisHB22 was shown to have a 1.4 kilobase deletion extending from the TGA termination codon of the hisC gene to the middle of the hisH gene. The sequence data were consistent with previous genetic and phenotypic characterization of these strains.Key words: Salmonella typhimurium, hisC gene, deletion mutants.
Dehalogenation by Mycobacterium vaccae JOB-5: role of the propane monooxygenase
Authors: Vanderberg Laura A. , Perry Jerome J.
Published: February 2010

Mycobacterium vaccae JOB-5 has an inducible propane monooxygenase that has been implicated in the catabolism of most major groundwater pollutants including trichloroethylene. Propane-grown cells are also induced for the dehalogenation of 1-chlorobutane and other chloroalkanes. 1-Chlorobutane is oxidized to 2-butanol, indicating that subterminal oxidation of 1-chlorobutane resulted in a concomitant release of the chloride. Nonproliferating suspensions of M. vaccae induced for the propane monooxygenase can dehalogenate a variety of chlorinated hydrocarbons including monochlorinated alcohols, dichlorinated short chain alkanes, and several multiple-substituted compounds including trichloroethylene. The results indicate that M. vaccae JOB-5 has a monooxygenase of broad specificity that can dehalogenate an array of halogenated hydrocarbons.Key words: dehalogenation, propane monooxygenase, chlorinated alkanes.
Regulation of two aspartokinase isozymes in Streptococcus bovis
Authors: Kalcheva E. O. , Faiziev M. M. , Shanskaya V. O. , Maluta S. S.
Published: February 2010

Streptococcus bovis has been found to contain two distinct aspartokinases that can be separated by gel filtration chromatography. One of these isozymes elutes on Sephadex G-200 gel filtration at a molecular weight greater than 250 000. The molecular weight of the other isozyme is approximately 125 000. The earlier peak of aspartokinase activity is slightly inhibited by meso-diaminopimelate, while the second peak is sensitive to inhibition by lysine. The latter aspartokinase is not formed when the organism is grown in a medium containing more than 1 mM lysine. The level of lysine-sensitive aspartokinase is decreased during the growth cycle, whereas diaminopimelate-sensitive activity is little affected by the growth conditions. The regulatory properties of the two aspartokinases suggest that they may play different physiological roles.Key words: aspartokinase activity, isozymes, repression, inhibition.
Membrane association and isolation of the S-layer protein of Methanoculleus marisnigri
Authors: Bayley Douglas P. , Koval Susan F.
Published: February 2010

Methanoculleus marisnigri is an irregularly shaped coccoid member of the methanogenic archaeobacteria. The cells possessed a hexagonally arranged, glycosylated S-layer as the sole wall component. The lattice spacing was approximately 13.5 nm. Plasmolysis in anaerobic medium with 20% sucrose did not separate the plasma membrane from the S-layer. The S-layer–membrane complex formed a tight but noncovalent association, was deformable, and was not a rigid structure. The 138-kDa glycoprotein was not solubilized by guanidine hydrochloride or urea, but it was solubilized in the detergent Triton X-100 at temperatures above 60 °C, and purified by phase separation at 75 °C of the detergent-soluble extract. The amino acid composition of the glycoprotein was similar to that reported for other S-layer proteins.Key words: methanogen, archaeobacteria (archaea), S-layer, glycoprotein, Triton X-100.
Parallel testing of media for measuring frequencies of occurrence for Halophytophthora spp. (Oomycota) from decomposing mangrove leaves
Authors: Newell S. Y. , Fell J. W.
Published: February 2010

Samples of submerged, decaying leaves of red, black, and white mangroves (Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa) were incubated on plates of eight different combinations of fungal inhibitors, bacterial inhibitors, and sporangium inducers added to a standard agar medium for isolating oomycotes (Protoctista: Oomycota; alias Oomycetes). The broad spectrum of agar preparations revealed no new oomycotic species for red or white mangroves; Halophytophthora vesicula (the delicate form) and Halophytophthora spinosa were overwhelmingly the most frequent species (to 88–90%, depending on medium, mangrove, and site). Other described species of Halophytophthora were rare (e.g., Halophytophthora bahamensis occurred twice, versus a total of 263 occurrences for H. spinosa). For black mangrove, however, the predominant oomycote (frequency ranging up to 90%, depending on medium and site) was an undescribed species of Halophytophthora with a mechanism of zoospore release involving the expansion of a clear plug into a tubular vesicle. Halophytophthora vesicula and H. spinosa occurred at almost four times lower frequencies on black mangrove than the undescribed Halophytophthora species. Media without inhibitors allowed interference from bacteria and labyrinthulas, with consequent reduction of oomycote frequencies by as much as a factor of four. Chloramphenicol application as the sole inhibitor at 150 mg∙L−1 resulted in significant interference from eumycotic fungi (oomycote frequency reductions to × 10). The best medium for exposing maximum frequencies of all three of the principal halophytophthoras was one with amphotericin B (2 mg∙L−1) as the polyene-macrolide fungal inhibitor.Key words: oomycotes, oomycetes, Halophytophthora, mangrove, selective medium.
Extracellular hemolytic activity in rapidly growing mycobacteria
Authors: Udou Takezo
Published: February 2010

Little is known about virulence factors associated with rapidly growing mycobacteria. We evaluated 42 clinical isolates of Mycobacterium fortuitum and Mycobacterium chelonae and 4 reference strains of Mycobacterium smegmatis for the production of hemolysin (or hemolytic substance) as a possible contributor to the pathogenesis of disease caused by these organisms. All the strains tested possessed extracellular hemolytic activity that was stable after heating and proteinase treatment, and the active substance had a molecular weight less than 10 000. The activity accumulated in culture medium during the late exponential to mid stationary phase of growth. Hemolysis in vitro was relatively slow; incubation for 10 h at 35 °C was required to obtain maximal activity. Some specificity of the hemolysis with regard to red blood cells from different animals was observed.Key words: rapidly growing mycobacteria, Mycobacterium fortuitum, Mycobacterium chelonae, Mycobacterium smegmatis, hemolytic activity.
Detection of rodlets in the outer wall region of conidiospores of Phanerochaete chrysosporium
Authors: Gerin P. A. , Asther M. , Sleytr U. B. , Rouxhet P. G.
Published: February 2010

The surface morphology of the conidiospores of Phanerochaete chrysosporium was investigated using freeze-etching. A multilayered structure composed of rodlets was detected. The rodlets had a diameter of 10.2 ± 0.5 nm and were organised as long parallel fibres. Granules, smooth materials, and bark-like structures were found to cover part of this rodlet layer. During germination, the outer pellicle of the spore wall became fragmented and residual aggregates with rodlets were disseminated on the new conidiospore surface. The latter, as well as the germ tube, was composed of fibrillar material.Key words: conidiospores, rodlet, surface, Phanerochaete chrysosporium, freeze-etching, fungal spore, germination.
Comparison of thermostable macromolecular antigens from leprosy-associated bacteria
Authors: Baelden M.-C. , Bouckaert A.-E. , Grégoire D. , Poele M. van de , Coene M.
Published: February 2010

Three types of bacteria are associated with leprosy: Mycobacterium leprae, leprosy-derived corynebacteria (LDC), and armadillo-derived mycobacteria (ADM). The immunological relationships between these three types of bacteria and Mycobacterium bovis BCG, used as a reference, were determined by cross-immunoelectrophoresis. When compared with the reference, cross-reactions were observed with a variable number of antigens: 2 in the case of strain LDC 15, 4 with M. leprae, and from 1 to 10 in the case of the ADM, depending on their subgroup. Next, thermostable macromolecular antigens (TMAs), the major cross-reactive antigens of leprosy-associated bacteria, were compared by anti-TMA antibody ELISA tests. The LDC TMAs displayed high cross-reactivity between the subgroups and lower cross-reactivity with the TMAs of M. bovis BCG. Evidence for the presence of a species-specific moiety in TMA of the different LDC was obtained by using depleted anti-TMA antisera. Western blot analysis revealed the presence of many proteins in the TMAs of LDC and M. bovis BCG, some of them being species-specific and other cross-reactive.Key words: Hansen's disease, mycobacteriosis, bacterial antigens, humoral immunity, antigen A60.
Cloning and sequence analysis of the hemB gene of Staphylococcus aureus
Authors: Kafala Badria , Sasarman A.
Published: February 2010

The hemB gene is a member of the family of genes encoding enzymes of the porphyrin biosynthetic pathway and codes for the enzyme porphobilinogen synthase, which is responsible for the conversion of Δ-aminolevulinic acid to porphobilinogen. To clone the hemB gene of Staphylococcus aureus we used Tn917-mediated transposon mutagenesis. Tn917 confers resistance to erythromycin and is carried by plasmid pTV1ts, which has thermosensitive replication. Hem mutants were selected by growth in the presence of kanamycin and erythromycin at 43 °C. Preliminary identification of the hem mutants was based on their dwarf colony growth, which could be restored to normal by hemin. DNA extracted from one of the hem mutants was digested with several restriction endonucleases and hybridized to a probe representing the XbaI–AvaI end of Tn917. A BglII–EcoRI fragment of 4.5 kb gave a positive signal and was cloned into pUC18. Transformants were identified by colony hybridization with the Tn917 probe. The positive clones were sequenced, starting from the transposon end. The results allowed us to identify an open reading frame whose nucleotide sequence presented a homology of 63% to the sequence of the hemB gene of Bacillus subtilis and of 55% to the sequence of the hemB gene of Escherichia coli K12. No other nucleotide sequences, except those belonging to known hemB genes, presented significant homologies to our sequence. The cloning of the hemB gene of S. aureus was confirmed by the ability of the gene to complement a hemB mutant of E. coli K12. To our knowledge, this is the first report of the cloning of a hem gene in S. aureus.Key words: Δ-aminolevulinic acid dehydratase, hemB gene, S. aureus, heme, porphyrins.
Study of lipids in Lipomyces and Waltomyces
Authors: Lomascolo A. , Dubreucq E. , Perrier V. , Galzy P.
Published: February 2010

The lipid composition, particularly the fatty acid composition (6–25 carbon atoms), of one strain of each species of Lipomyces and Waltomyces was determined; the influence of the culture temperature on the lipid composition was also studied. The neutral lipid fraction, essentially composed of intracellular triacylglycerols, and the polar fraction, composed of membrane phospholipids, were analyzed separately. For all strains and in the two fractions, the major fatty acids were oleic, linoleic, palmitic, palmitoleic, stearic, and α-linolenic acids, which formed 85% of the total fatty acids. Small amounts of γ-linolenic, dihomo-γ-linolenic, and arachidonic acids were present, which indicated the presence of Δ12, Δ15, Δ6, and Δ5 desaturases. Waltomyces lipofer and Lipomyces tetrasporus were the two species richest in lipids and fatty acids. In the genus Lipomyces and in Waltomyces, maintenance of membrane fluidity at low temperature required an increase in unsaturated fatty acids and the accumulation of short-chain fatty acids, especially in the polar lipid fraction; in the case of Lipomyces anomalus, the synthesis of branched fatty acids may be a third way to maintain membrane fluidity.Key words: Lipomyces, Waltomyces, lipid composition, fatty acids.
Survival of mycorrhizal fungal isolates stored in sterile water at two temperatures and retrieved on solid and liquid nutrient media
Authors: Smith Jane E. , McKay Donaraye , Molina Randy
Published: February 2010

Vegetatively colonized agar cores of 169 reputed mycorrhizal fungal isolates, representing 18 Ascomycotina, 141 Basidiomycotina, and 10 Deuteromycotina fungi, were stored at 4 and 18 °C in tubes of sterile deionized water. Viability, based on growth on solid and liquid nutrient media at 18 °C, was determined after a 20-month storage period. Ninety-five percent of the isolates were retrieved in at least one of three treatments: 89% in liquid nutrient media and 84% on solid media after storage at 18 °C, and 78% on solid media after storage at 4 °C. Nearly all Ascomycotina and Deuteromycotina isolates were retrieved regardless of the storage temperature or form of retrieval medium. Basidiomycotina isolates differed more in survival and percentage of viability than Ascomycotina or Deuteromycotina. For example, storage temperature influenced the viability of Laccaria isolates and the form of retrieval medium influenced the viability of Rhizopogon isolates.Key words: culture maintenance, fungal storage, long-term storage, mycorrhizal fungal isolates, water storage.
Transformation of Bartonella bacilliformis by electroporation
Authors: Grasseschi Helen A. , Minnick Michael F.
Published: February 2010

Bartonella bacilliformis is a member of the order Rickettsiales, family Bartonellaceae. The bacterium is an intracellular parasite of human erythrocytes. To date, members of the family Bartonellaceae have not been transformed by standard chemical methods. We report the first successful transformation of a member of the Bartonellaceae family, B. bacilliformis, by the method of electroporation. The optimal conditions for electroporation of B. bacilliformis include a field strength of 12.5 kV/cm and a time constant of 5 ms using 0.2-cm cuvettes. With these parameters and the cosmid pEST (RK2 replicon), a transformation efficiency of 7.8 × 105 was obtained. Transformants were readily cultured on medium containing kanamycin sulfate at concentrations ranging from 15 to 600 μg/mL. Bacterial survival was approximately 31% under optimal electroporation conditions, and the maximal number of transformants was obtained with 80 ng of pEST DNA. Bartonella bacilliformis was verified as the transformed organism by a comparison of transformant protein profiles with those of wild-type B. bacilliformis using sodium dodecyl sulfate polyacrylamide gel electrophoresis, and detection of the exogenous plasmid in DNA from the transformed bacteria by DNA hybridization. Transformations using the plasmids pMK20, pML31, and pUCK18 (containing the replicons ColE1, F, and pMB1, respectively) were not successful.Key words: transformation, electroporation, Rickettsiales order.
Isolation and characterization of mutants of Rhizobium meliloti unable to synthesize poly-β-hydroxybutyrate
Authors: Povolo Silvana , Tombolini Riccardo , Morea Antonella , Anderson Alistair J. , Casella Sergio , Nuti Marco P.
Published: February 2010

The isolation and characterization of four mutants of Rhizobium meliloti unable to synthesize poly-β-hydroxybutyrate (PHB) are reported. The mutants were independently obtained via Tn5 transposon mutagenesis and exhibited physiological and cytomorphological characteristics similar to those of the parental strain, as well as overlapping DNA profiles. These were assessed at both the plasmid and total genome level, using for the latter the sensitive technique of pulsed-field gel electrophoresis in a contour-clamped homogeneous electric field. With respect to the parental PHB+ strain, the loss of PHB-synthesizing ability in the four mutants was demonstrated by gas chromatography, transmission electron microscopy, and enzymatic tests. Localization studies of Tn5 insertion showed that the PHB− phenotype had, in all mutants, a transposon insertion in the same region, although not in the same position. The symbiotic traits (nodule-inducing ability on Medicago sativa and acetylene-reducing activity of nodules) of the mutants did not differ significantly from those of the parental R. meliloti.Key words: Rhizobium meliloti, poly-β-hydroxybutyrate (PHB), PHB synthase.
Partial purification and characterization of 1-aminocyclopropane-1-carboxylate deaminase from the plant growth promoting rhizobacterium Pseudomonas putida GR12-2
Authors: Jacobson Christian B. , Pasternak J. J. , Glick Bernard R.
Published: February 2010

The plant growth promoting rhizobacterium Pseudomonas putida GR12-2 can utilize 1-aminocyclopropane-1-carboxylate (ACC) as a sole nitrogen source because it possess the unusual enzyme ACC deaminase, which hydrolyzes ACC to ammonia and α-ketobutyrate. This enzyme, which is thought to be intimately involved in the mechanism that the bacterium uses to promote root elongation in developing canola seedlings, was partially purified and characterized. The native form of the enzyme is a trimer with a molecular mass of 105 kDa and a subunit molecular mass of 35 kDa. ACC deaminase activity is found in the cytoplasm of the bacterium, is induced by low levels (i.e., 100 nM) of ACC, and has a temperature optimum at approximately 30 °C and a pH optimum of 8.5. These properties are very similar to those reported for ACC deaminase from another soil bacterium, Pseudomonas sp. strain APC.Key words: 1-aminocyclopropane-1-carboxylate, ACC, plant growth promoting rhizobacteria, PGPR, ACC deaminase, bacterial fertilizer.
Characterization of the drug resistance plasmid R2418: restriction map and role of insertion and deletion in its evolution
Authors: Guessouss Mohamed , Ben-Mahrez Kamel , Belhadj Cherifa , Belhadj Omrane
Published: February 2010

Escherichia coli 2418 strain is resistant to β-lactam antibiotics (ampicillin, carbenicillin, and cephalothin), streptomycin, tetracycline, kanamycin, and chloramphenicol. This strain contains at least two conjugative plasmids (R2418 and R2418S) encoding resistance to β-lactam antibiotics and resistance to both β-lactam antibiotics and streptomycin, respectively. Restriction endonuclease mapping of plasmid DNAs indicates that the plasmid R2418S has evolved from R2418 DNA by the insertion of 2.5-kb DNA between BamHI and PvuII sites, and deletion of 0.5-kb DNA within the EcoRI–EcoRV region. The 2.5-kb DNA insert is responsible for streptomycin resistance. This evolution is also associated with a reduction in the efficiency of conjugal transfer for the plasmid R2418S. The conjugal transfer of streptomycin resistance occurs only through the coresidence of the conjugative plasmid R2418 or R2418S in the donor cell. In accordance with the hypothesis that the Smrdeterminant is due to a putative transposon, plasmid-free transconjugants resistant to streptomycin only were isolated. Southern blot analysis of HindIII chromosomal digests extracted from these transconjugants shows that the Smrdeterminant is inserted into different sites in chromosomal DNA.Key words: Escherichia coli, antibiotic resistance, conjugation, transformation, plasmid, transposon, restriction map.
Bacteriocin 28b fromSerratia marcescensN28b: identification ofEscherichia colisurface components involved in bacteriocin binding and translocation
Authors: Enfedaque Josefina , Ferrer Santiago , Guasch Joan Francesc , Regué Miguel , Tomás Joan
Published: February 2010

Serratia marcescens N28b produces bacteriocin 28b, active against Escherichia coli. Bacteriocin sensitivity tests performed on a collection of E. coli envelope mutants, and isolation and characterization of E. coli bacteriocin-28b-insensitive mutants, showed that the core lipopolysaccharide, outer membrane proteins OmpA and OmpF, and TolQ, TolA, and TolB proteins are involved in bacteriocin 28b lethal activity. These mutants were assayed for bacteriocin 28b sensitivity under normal and bypass conditions, and their bacteriocin-binding ability was determined. The results obtained suggest that the core lipopolysaccaride and outer membrane proteins OmpA and OmpF are involved in bacteriocin 28b binding. Furthermore, bacteriocin 28b translocation requires proteins TolA, TolB, and TolQ.Key words: bacteriocin, receptors, translocation, Serratia marcescens.
UV photoaffinity labeling of Tn3transposase–DNA complexes: identification of DNA binding domains
Authors: Gottlieb Geoffrey S. , Fennewald Michael A.
Published: February 2010

The prokaryotic transposon Tn3 requires the transposase protein, as well as the cis-acting terminal inverted repeats (IRs), for transposition. The first step in the transposition process requires transposase binding to the IRs, as well as target site selection for element insertion. The primary aim of this study is to define the relationship between the structure of Tru3 transposase and its DNA binding functions. We have defined, by UV cross-linking, two broad regions of transposase that interact with DNA: a 70-kDa N-terminal domain and a 30-kDa C-terminal domain. The 70-kDa N-terminal domain encompasses the IR sequence-specific binding domain, as well as a nonspecific DNA binding domain that has been previously described. We have also defined, by UV cross-linking, a region in the nonspecific DNA binding domain centered at amino acids 376 and 381 that is in contact with DNA. We have used site-directed mutagenesis of amino acids 376 and 381 to help delineate the function of this region of the transposase protein. Mutations in this region reduce transposition frequency to 30–40% of the wild type. These mutations reduce nonspecific DNA binding three- to four-fold but do not appear to affect specific binding to the IR. Transposition immunity is unaffected by mutations in the nonspecific DNA binding domain. This suggests that this region may be involved in target site selection.Key words: transposon, Tn3, DNA–protein cross-linking, UV cross-linking, transposase.
Root nodulation of Sesbania rostrata suppresses stem nodulation by Sinorhizobium teranga but not Azorhizobium caulinodans
Authors: Tomekpe Kodjo , Holsters Marcelle , Dreyfus Bernard
Published: February 2010

Azorhizobium caulinodans ORS571 and Sinorhizobium teranga ORS51 and ORS52 are symbionts of the same host plant Sesbania rostrata. In nature, A. caulinodans nodulates more competitively the stem-located infection sites of Sesbania rostrata. Sinorhizobium strains, although frequently present in root nodules, are seldom found in stem nodules. One probable explanation for this phenomenon is the more abundant presence of Azorhizobium on the leaf and stem surfaces of the host plant. Work presented here hints at other plausible factors that determine the greater "stem specificity" of Azorhizobium. We found that under experimental conditions in which roots are not inoculated, all strains nodulated stems very well. However, ORS51 and ORS52 were much more sensitive than ORS571 to suppression of stem nodulation by previous root inoculation. The introduction of the regulatory nodD gene from A. caulinodans diminished the sensitivity to this suppression, probably by enhanced nod gene expression and subsequent Nod factor production. Our hypothesis is that the greater infectivity of ORS571 is due to a more efficient production of mitogenic Nod factors at stem-located infection sites, thereby more readily overcoming systemic suppression caused by previous root inoculations.Key words: autoregulation, nitrogen fixation, rhizobial ecology, systemic suppression of nodulation.
Isolation and characterization of soil microorganisms capable of utilizing the herbicide diclofop-methyl as a sole source of carbon and energy
Authors: Smith-Grenier L. L. , Adkins A.
Published: February 2010

Six nonfermentative Gram-negative bacilli were isolated from Manitoban soils after enrichment with diclofopmethyl. Microscopic examination and physiological and biochemical tests have identified the organisms as Sphingomonas paucimobilis, Acinetobacter baumannii, Chryseomonas luteola, Pseudomonas aureofaciens, Pseudomonas cepacia, and Pseudomonas fluorescens. Growth curve studies showed that each of the isolates was able to grow in minimal medium with diclofop-methyl as the sole source of carbon and energy. Chemical analysis confirmed that all of the added diclofop-methyl (1.5 μg ∙ mL−1) had been utilized after 31 h of incubation at 25 °C Key words: diclofop-methyl, biodegradation, herbicide.