bluuebunny/crossref_metadata_2025 huggingface dataset:
Shear‐dependent ‘stick‐and‐roll’ adhesion of type 1 fimbriated Escherichia coli
Authors: Thomas Wendy E. , Nilsson Lina M. , Forero Manu , Sokurenko Evgeni V. , Vogel Viola
Published: August 2004

It is generally assumed that bacteria are washed off surfaces as fluid flow increases because they adhere through ‘slip‐bonds’ that weaken under mechanical force. However, we show here that the opposite is true for Escherichia coli attachment to monomannose‐coated surfaces via the type 1 fimbrial adhesive subunit, FimH. Raising the shear stress (within the physiologically relevant range) increased accumulation of type 1 fimbriated bacteria on monomannose surfaces by up to two orders of magnitude, and reducing the shear stress caused them to detach. In contrast, bacterial binding to anti‐FimH antibody‐coated surfaces showed essentially the opposite behaviour, detaching when the shear stress was increased. These results can be explained if FimH is force‐activated; that is, that FimH mediates ‘catch‐bonds’ with mannose that are strengthened by tensile mechanical force. As a result, on monomannose‐coated surfaces, bacteria displayed a complex ‘stick‐and‐roll’ adhesion in which they tended to roll over the surface at low shear but increasingly halted to stick firmly as the shear was increased. Mutations in FimH that were predicted earlier to increase or decrease force‐induced conformational changes in FimH were furthermore shown here to increase or decrease the probability that bacteria exhibited the stationary versus the rolling mode of adhesion. This ‘stick‐and‐roll’ adhesion could allow type 1 fimbriated bacteria to move along mannosylated surfaces under relatively low flow conditions and to accumulate preferentially in high shear regions.
Role of two essential domains of Escherichia coli FtsA in localization and progression of the division ring
Authors: Rico Ana Isabel , García‐Ovalle Marta , Mingorance Jesús , Vicente Miguel
Published: August 2004

The FtsA protein is a member of the actin superfamily that localizes to the bacterial septal ring during cell division. Deletions of domain 1C or the S12 and S13 β‐strands in domain 2B of the Escherichia coli FtsA, previously postulated to be involved in dimerization, result in partially active proteins that do not allow the normal progression of septation. The truncated FtsA protein lacking domain 1C (FtsAΔ1C) localizes in correctly placed division rings, together with FtsZ and ZipA, but does not interact with other FtsA molecules in the yeast two‐hybrid assay, and fails to recruit FtsQ and FtsN into the division ring. The rings containing FtsAΔ1C are therefore incomplete and do not support division. The production of high levels of FtsAΔ1C causes filamentation, an effect that has been reported to result as well from the imbalance between FtsA+ and FtsZ+ molecules. These data indicate that the domain 1C of FtsA participates in the interaction of the protein with other FtsA molecules and with the other proteins that are incorporated at later stages of ring assembly, and is not involved in the interaction with FtsZ and the localization of FtsA to the septal ring. The deletion of the S12–S13 strands of domain 2B generates a protein (FtsAΔS12–13) that retains the ability to interact with FtsA+. When the mutated protein is expressed at wild‐type levels, it localizes into division rings and recruits FtsQ and FtsN, but it fails to sustain septation at normal levels resulting in filamentation. A fivefold overexpression of FtsAΔS12–13 produces short cells that have normal division rings, but also cells with polar localization of the mutated protein, and cells with rings at abnormal positions that result in the production of a fraction (15%) of small nucleoid‐free cells. The S12–S13 strands of domain 2B are not essential for septation, but affect the localization of the division ring.
A rapid method for direct detection of Polymyxa DNA in soil
Authors: Ward L. I. , Fenn M. G. E. , Henry C. M.
Published: August 2004

Polymyxa spp. are vectors for a number of economically important soilborne plant viruses. The development of a technique to detect virus and vectors directly in soil would be useful for epidemiological studies and assessment of disease risk prior to planting. A rapid method was developed to extract and quantify Polymyxa spp. DNA from soils. DNA was extracted from three soils infested with Polymyxa betae and three infested with P. graminis using an EDTA lysis buffer in combination with a MagneSil™ DNA extraction kit and Kingfisher™ magnetic particle processor. Primers and probes designed to correspond to sequences within the internal transcribed spacer region 2 (ITS2) of ribosomal DNA enabled recovery and amplification of P. betae and P. graminis DNA using real‐time PCR and TaqMan chemistry. For the P. graminis‐infested soils, the purity of DNA obtained was sufficient to allow Polymyxa DNA to be amplified without dilution to remove inhibitors, but with P. betae‐infested soils, amplification was only achieved if the DNA was diluted 1:10. Using TaqMan PCR, a standard curve was constructed from uninfested soil spiked with known numbers of P. betae cystosori; the quantity of P. betae inoculum from naturally infested soil was then extrapolated from the curve. This technique offers a sensitive method of extracting, detecting and quantifying Polymyxa spp. DNA in soil.
Aggressiveness and host specificity of Brazilian isolates of Phytophthora infestans
Authors: Suassuna N. D. , Maffia L. A. , Mizubuti E. S. G.
Published: August 2004

The population of Phytophthora infestans in Brazil consists of two clonal lineages, US‐1 associated with tomatoes and BR‐1 associated with potatoes. To assess whether host specificity in these lineages resulted from differences in aggressiveness to potato and tomato, six aggressiveness‐related epidemiological components – infection frequency (IF), incubation period (IP), latent period (LP), lesion area (LA), lesion expansion rate (LER) and sporulation at several lesion ages (SSLA) – were measured on detached leaflets of late blight‐susceptible potato and tomato plants. Infection frequency of US‐1 was similar on potato and tomato leaflets, but IF of BR‐1 was somewhat reduced on tomato. Incubation period was longer on both hosts with US‐1, although this apparent lineage affect was not significant. Overall there was no host effect on IP. On potato, BR‐1 had a shorter LP (110·3 h) and a larger LA (6·5 cm2) than US‐1 (LP = 162·0 h; LA = 2·8 cm2). The highest LER resulted when isolates of BR‐1 (0·121 cm2 h−1) and US‐1 (0·053 cm2 h−1) were inoculated on potato and tomato leaflets, respectively. The highest values of the area under the sporulation capacity curve (AUSC) were obtained for isolates of US‐1 inoculated on tomato leaflets (6146) and for isolates of BR‐1 on potato leaflets (3775). In general, higher values of LA, LER, SSLA and AUSC, and shorter values of LP were measured when isolates of a clonal lineage were inoculated on their original host than with the opposite combinations. There is evidence that there are quantitative differences in aggressiveness components between isolates of US‐1 and BR‐1 clonal lineages that probably contribute to host specificity of P. infestans populations in Brazil.
Weather‐based prediction of anthracnose severity using artificial neural network models
Authors: Chakraborty S. , Ghosh R. , Ghosh M. , Fernandes C. D. , Charchar M. J. , Kelemu S.
Published: August 2004

Data were collected and analysed from seven field sites in Australia, Brazil and Colombia on weather conditions and the severity of anthracnose disease of the tropical pasture legumeStylosanthes scabracaused byColletotrichum gloeosporioides. Disease severity and weather data were analysed using artificial neural network (ANN) models developed using data from some or all field sites in Australia and/or South America to predict severity at other sites. Three series of models were developed using different weather summaries. Of these, ANN models with weather for the day of disease assessment and the previous 24 h period had the highest prediction success, and models trained on data from all sites within one continent correctly predicted disease severity in the other continent on more than 75% of days; the overall prediction error was 21·9% for the Australian and 22·1% for the South American model. Of the six cross‐continent ANN models trained on pooled data for five sites from two continents to predict severity for the remaining sixth site, the model developed without data from Planaltina in Brazil was the most accurate, with >85% prediction success, and the model without Carimagua in Colombia was the least accurate, with only 54% success. In common with multiple regression models, moisture‐related variables such as rain, leaf surface wetness and variables that influence moisture availability such as radiation and wind on the day of disease severity assessment or the day before assessment were the most important weather variables in all ANN models. A set of weights from the ANN models was used to calculate the overall risk of anthracnose for the various sites. Sites with high and low anthracnose risk are present in both continents, and weather conditions at centres of diversity in Brazil and Colombia do not appear to be more conducive than conditions in Australia to serious anthracnose development.
Growth in vitro and infectivity of Colletotrichum coccodes on potato tubers at different temperatures
Authors: Glais‐Varlet I. , Bouchek‐Mechiche K. , Andrivon D.
Published: August 2004

To investigate the ability of black dot symptoms to develop on infected potato tubers during storage, the growth of Colletotrichum coccodes was followed in vitro on malt agar at temperatures ranging from 5–27°C, and in vivo on artificially infected potato tubers kept at 5, 10 and 15°C. In vitro, 13 isolates from different geographical origins grew at all temperatures tested; growth started with a delay of 10 days at 5°C and of 4 days at 10°C, and was fastest at 27°C. All isolates had similar growth patterns and produced conidia and sclerotia at all temperatures. Minitubers were successfully infected at 5, 10 and 15°C by depositing either a mycelial plug or a drop of conidial suspension on the tuber surface. Sclerotia were observed after 7 days at the point of inoculation. Symptoms extended in all cases, although more slowly at 5 and 10 than at 15°C. Latent infections were detected in up to 21% of tubers without black dot symptoms at harvest. These results show that latent infections by C. coccodes are probably quite frequent, and that the pathogen is able to develop at low temperatures in controlled conditions. This suggests that black dot symptoms can increase during storage if stores are not adequately managed.
Potential for using host resistance to reduce production of pseudothecia and ascospores of Leptosphaeria maculans, the blackleg pathogen of Brassica napus
Authors: J. Marcroft S. , Sprague S. J. , Salisbury P. A. , Howlett B. J.
Published: August 2004

Pseudothecial density of the blackleg fungus Leptosphaeria maculans and discharge of ascospores was measured from stubble of a range of Brassica species, including Brassica napus (canola) cultivars, with a range of blackleg resistance. Since ascospores are the primary inoculum, these parameters reflect inoculum potential for blackleg. Stubble from a representative line of each of B. carinata, B. nigra, Sinapis alba and B. napus cv. Surpass 400 (incorporates blackleg resistance from B. rapa ssp. sylvestris) had lower pseudothecial density and discharged fewer ascospores than stubble of other B. napus cultivars (Karoo, Oscar, Emblem, Dunkeld and Columbus). These latter B. napus cultivars and a representative B. juncea line had higher pseudothecial densities and discharged higher numbers of ascospores. If this trait of low blackleg inoculum from stubble could be introgressed into commercial canola cultivars, blackleg disease severity could be substantially reduced, resulting in higher and more stable canola yields. However, the trait of reduced ascospore discharge may not be stable, as demonstrated by the B. rapa ssp. sylvestris‐derived resistance already being overcome by the blackleg fungus in Australia.
Sources of resistance to septoria tritici blotch and implications for wheat breeding
Authors: Chartrain L. , Brading P. A. , Makepeace J. C. , Brown J. K. M.
Published: August 2004

Twenty‐four wheat cultivars and breeding lines were screened for isolate‐specific resistance to septoria tritici blotch (STB) caused by 12 isolates of Mycosphaerella graminicola. New isolate‐specific resistances that could be used in wheat breeding were identified. Major sources of resistance to STB used in world breeding programmes for decades, such as Kavkaz‐K4500, Veranopolis, Catbird and TE9111, have several isolate‐specific resistances. This suggests that ‘pyramiding’ several resistance genes in one cultivar may be an effective and durable strategy for breeding for resistance to STB in wheat. Several cultivars, including Arina, Milan and Senat, had high levels of partial resistance to most isolates tested as well as isolate‐specific resistances. Resistance to isolate IPO323 was common, present in all but one of the major sources of resistance tested. This suggests that resistance to IPO323 may be an indicator of varietal resistance to STB in the field.
Host–parasite relationships of Meloidogyne incognita on spinach
Authors: Di Vito M. , Vovlas N. , Castillo P.
Published: August 2004

Host–parasite relationships in root‐knot disease of spinach caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Nematode‐induced mature galls were large and usually contained one or more females and egg masses with eggs. Feeding sites were characterized by the development of giant cells containing granular cytoplasm and many hypertrophied nuclei. The cytoplasm in these giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density (Pi) in a series from 0–128 eggs and second‐stage juveniles per cm3 soil and growth of spinach cv. Symphony F1 seedlings was tested under glasshouse conditions. A Seinhorst model [y = m + (1 − m)zP–T] was fitted to fresh top‐ and total plant‐weight data for inoculated and control plants. Tolerance limits (T) of spinach cv. Symphony F1 to M. incognita race 1 for fresh top and total plant weights were 0·25 and 0·5 eggs and second‐stage juveniles per cm3 soil, respectively. The minimum relative values for fresh top and total plant weights were zero in both cases at Pi ≥ 32 eggs and second‐stage juveniles per cm3 soil. Root galling was least at low initial population densities and greatest at 16 eggs and second‐stage juveniles per cm3 soil. Maximum nematode reproduction rate was 33·1‐fold at the lowest Pi.
Establishment of, and preliminary impact studies on, the rust, Maravalia cryptostegiae, of the invasive alien weed, Cryptostegia grandiflora in Queensland, Australia
Authors: Tomley A. J. , Evans H. C.
Published: August 2004

The rust fungus Maravalia cryptostegiae, from south‐west Madagascar, was introduced into Australia in 1995 as a classical biological control agent against the highly invasive rubber‐vine weed Cryptostegia grandiflora, a woody climber endemic to Madagascar. The rust was released at 69 sites between 1995 and 1997 and is now established throughout the plant's exotic range in Queensland, estimated at over 40 000 km2. Dispersal was low in the first 3–4 months but was virtually linear thereafter, and the rust spread over 100 km within the first year; after 3 years it was recorded 550 km away from the nearest release site. Spraying both dry and aqueous inoculum of uredinioid teliospores from the ground using mist‐blowers, as well as from the air by atomizing spore suspensions, resulted in rust‐induced defoliation, producing an overall reduction in fecundity and biomass of the weed. In sites with low water tables, weed growth decreased markedly, with a reduction in plant volume from 9 m−3 to 1 m−3 over a 4‐year period. Both rust‐ and drought‐induced stress combined to cause up to 75% plant mortality at some sites, and at all monitored sites, seedling recruitment was virtually nil. Improved growth of indigenous grasses amongst rubber‐vine thickets has increased fuel loads and created opportunities to use fire as a component of an integrated approach to the management of this economically and ecologically damaging weed.
Salivary IgA to cariogenic bacteria in HIV‐positive children and its correlation with caries prevalence and levels of cariogenic microorganisms
Authors: Castro G. F. , Souza I. P. R. , Lopes S. , Stashenko P. , Teles R. P.
Published: August 2004

The interrelationship of HIV infection, dental caries and mucosal immune responses remains controversial. In our study population of 40 HIV‐infected and 40 healthy control children (ages 2–5 years) there was a significantly higher prevalence of dental caries in HIV‐infected children (P<0.05). The extent of caries correlated with the severity of HIV disease. To determine whether the immunosuppression that ensues after HIV infection could contribute to the increased caries prevalence, the concentrations of total IgA and IgA specific to cariogenic bacteria (Streptococcus mutans, Streptococcus sobrinus and Lactobacillus acidophilus) were determined in whole saliva by enzyme‐linked immunosorbent assay . Levels of the same bacteria were also quantified in saliva using checkerboard DNA–DNA hybridization. A significantly increased level of total salivary IgA was found in the HIV‐positive population (P < 0.05), but there were comparable titers of specific IgA to cariogenic bacteria in HIV‐positive and healthy controls. The microbiological assessment also demonstrated similar levels of cariogenic microorganisms in both groups. We conclude that HIV‐positive children appear to maintain the capacity to mount a mucosal immune response to cariogenic microorganisms, at least until late stages of disease.
Prevalence of Porphyromonas gingivalis in relation to periodontal status assessed by real‐time PCR
Authors: Kawada M. , Yoshida A. , Suzuki N. , Nakano Y. , Saito T. , Oho T. , Koga T.
Published: August 2004

Many studies have examined the presence of Porphyromonas gingivalis in periodontal pockets. However, monitoring the number of bacterial cells is difficult. In this study, we performed quantitative analyses of P. gingivalis to clarify the relationship between the numbers of this organism and periodontal status. Using the TaqMan real‐time PCR system, we found a significant positive correlation (P < 0.0001) between the number of P. gingivalis and pocket depth. The slope of the regression line indicated that for every 1‐mm increase in pocket depth, the number of P. gingivalis increased 10‐ fold. There was also a significant reduction (P < 0.01) in the numbers of P. gingivalis before and after treatment. These results suggest that the absolute and relative numbers of P. gingivalis are closely associated with periodontal status, and that quantitative analysis of this organism is important for the evaluation of periodontal therapy.
Treponema species associated with abscesses of endodontic origin
Authors: Siqueira J. F. , Rôças I. N.
Published: August 2004

Spirochetes have been frequently observed in abscesses of endodontic origin, but they have rarely been identified. This study sought to investigate the prevalence of eight oral treponemes in acute periradicular abscesses using a species‐specific nested polymerase chain reaction assay. Purulent exudate was collected by aspiration from 19 cases diagnosed as acute periradicular abscesses and DNA extracted from the samples was initially amplified using universal 16S rDNA primers. A second round of amplification used the first polymerase chain reaction products to detect a specific fragment of the 16S rDNA of each Treponema species. The species‐specific nPCR assay used in this study allowed the detection of Treponema denticola in 79%(15 of 19), Treponema socranskii in 26%(5 of 19), Treponema pectinovorum in 21% (4 of 19), Treponema amylovorum in 16% (3 of 19), and Treponema medium in 5% (1 of 19) of the cases. Spirochetal DNA was found in 89% of the cases (17 of 19). The number of Treponema species per case ranged from 1 to 3 (mean, 1.5). Treponema vincentii, Treponema lecithinolyticum and Treponema maltophilum were not detected in any pus sample. The present data lend support to the assertion that Treponema species, particularly T. denticola and T. socranskii, may be involved in the pathogenesis of acute periradicular abscesses.
Clonal distribution of natural competence in Actinobacillus actinomycetemcomitans
Authors: Fujise O. , Lakio L. , Wang Y. , Asikainen S. , Chen C
Published: August 2004

The competence for natural transformation was investigated in 67 Actinobacillus actinomycetemcomitans strains. The transformation assays were performed with both cloned DNA fragments and chromosomal markers of A. actinomycetemcomitans. Competence was found in 12 of 18 serotype a strains, 0 of 21 serotype b strains, 0 of 14 serotype c strains, 3 of 6 serotype d strains, 3 of 4 serotype e strains, 0 of 3 serotype f strains, and 0 of 1 nonserotypeable strain. The transformation frequencies varied from 5 × 10−3 to 4 × 10−6 (median 1.5 × 10−4). The distribution pattern of natural competence is concordant with the major clonal lineages of A. actinomycetemcomitans. Serotype a strains are predominantly competent for transformation, while serotypes b and c strains are apparently non‐competent.
A simple approach to examine early oral microbial biofilm formation and the effects of treatments
Authors: Sreenivasan P. K. , Mattai J. , Nabi N. , Xu T. , Gaffar A.
Published: August 2004

Background/aims:  A simple in vivo approach to examine early dental plaque formation in the human mouth and to determine the effects of common dietary and oral hygiene procedures on biofilm formation is reported.

Methods:  A custom designed device that fits securely behind the teeth of the mandibular arch provides a surface for microbial colonization. This device is prepared with denture acrylic and can be repeatedly used by the subject, exposing a large and constant surface area for microbial accumulation.

Results:  Large numbers of oral bacteria colonized the device by 2 h; these increased significantly by 4 h (P < 0.05). Bacterial colonization increased significantly after rinsing with a sucrose solution (P < 0.05) but remained unaffected after rinsing with water, a commercially available fluoride mouthrinse without antimicrobial agents, or brushing with a fluoride dentifrice (P > 0.05). Rinsing with mouthrinses formulated with chlorhexidine, cetylpyridinium chloride or triclosan/copolymer significantly inhibited colonization (P < 0.05). A dose‐dependent inhibition was noted with chlorhexidine rinses (P < 0.05). Brushing with a triclosan/copolymer dentifrice significantly inhibited microbial colonization compared with a control (P < 0.05).

Conclusion:  This simple approach was useful for examining the effects of common dietary and oral hygiene procedures. Significant biofilm inhibitory effects were noted with formulations that demonstrated efficacy in previous clinical studies.
β‐Lactamase production and antimicrobial susceptibility of subgingival bacteria from refractory periodontitis
Authors: Handal T. , Olsen I. , Walker C. B. , Caugant D. A.
Published: August 2004

This study assessed the extent of β‐lactamase‐producing bacteria in subgingival plaque samples obtained from 25 patients with refractory marginal periodontitis in the USA. β‐Lactamase‐positive isolates were characterized using commercial diagnostic kits and partial sequencing of the 16S rRNA gene. The susceptibilities to different antimicrobial agents were tested and, in addition, the isolates were screened for the presence of extended spectrum β‐lactamases (ESBLs). β‐lactamase‐producing bacteria were detected in 18 (72%) patients. The most prominent β‐lactamase‐producing organisms belonged to the anaerobic genus Prevotella. Other enzyme‐producing anaerobic strains were Fusobacterium nucleatum, Propionibacterium acnes and Peptostreptococcus sp. Facultative bacteria, such as Burkholderia spp., Ralstonia pickettii, Capnocytophaga spp., Bacillus spp., Staphylococcus spp. and Neisseria sp., were also detected among the enzyme‐producers. Minimum inhibitory concentrations (MICs) of ampicillin and amoxicillin were in the range 1.5–256 μg/ml and 4–256 μg/ml, respectively, for the isolates of the Prevotella species. All Prevotella isolates were susceptible to amoxicillin/clavulanate and metronidazole, but they showed variable resistance to tetracyclines. Two of the Prevotella isolates had high MICs of cefotaxime and ceftazidime. ESBL activity was not detected in any of the β‐lactamase‐producing isolates by the Etest method. Thus, our study demonstrated a wide variety of β‐lactamase‐producing bacteria that may play a role in refractory periodontal disease.
Effects of low dose chlorhexidine mouthrinses on oral bacteria and salivary microflora including those producing hydrogen sulfide
Authors: Sreenivasan P. K. , Gittins E.
Published: August 2004

Background/aims:  Clinical studies have demonstrated the considerable effects of chlorhexidine on dental plaque and oral microbiota as well as improvements in indices of oral health. This investigation examined the efficacy of lower concentrations of chlorhexidine.

Methods:  Mouthrinses with 0.03%, 0.06%, 0.12% chlorhexidine and a control rinse without chlorhexidine were examined. Alamar blue, an oxidation‐reduction dye with fluorescent end‐points proportional to bacterial viability, was used to determine bacterial viability. Further clinical studies examined the effects of these rinses on salivary bacteria and on bacteria producing hydrogen sulfide (H2S) and implicated in halitosis.

Results:  In laboratory tests, a significant dose‐dependent effect was observed with Actinomyces viscosus as a model system using the Alamar blue procedure (P < 0.05). Clinical studies examined the effects 1.5 h and 3 h post‐treatment on salivary bacteria and bacteria producing H2S. The first study compared the control rinse with the 0.03% and 0.06% chlorhexidine rinses; a second study compared the effects of the control rinse and the 0.06% and 0.12% chlorhexidine mouthrinses. In both studies, chlorhexidine rinses demonstrated significant dose‐dependent effects post‐treatment on salivary bacteria vs. the control rinse (P < 0.05). Significant decreases in H2S‐producing bacteria were noted with these chlorhexidine rinses vs. the control rinse (P < 0.05).

Conclusion:  The results highlight the dose‐dependent relationships noted in laboratory and clinical tests which have potential implications for the use of lower doses of chlorhexidine to inhibit oral bacteria, including those implicated in halitosis.
Microbiological profile of early onset/aggressive periodontitis patients
Authors: Kamma J. J. , Nakou M. , Gmür R. , Baehni P. C.
Published: August 2004

Objectives:  The objectives of this study were to characterize the bacterial profile and to seek possible bacterial associations in the subgingival microbiota of early onset periodontitis/aggressive periodontitis patients by using two different techniques, culture and immunofluorescence.

Material and methods:  The study group consisted of 66 systemically healthy individuals with evidence of early onset periodontitis − 41 females and 25 males aged 23–35 years (mean 31.1 ± 3.1 years). Bacterial samples were collected from the deepest site in each quadrant, resulting in a total of 264 sites with a mean probing pocket depth of 6.6 ± 1.5 mm. Samples were cultured anaerobically and in 10% CO2 using selective and nonselective media, and isolates were characterized to species level. Indirect immunofluorescence using monoclonal antibodies was applied to detect Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia (Bacteroides forsythus, Tannerella forsythensis), Prevotella intermedia/Prevotella nigrescens, Campylobacter rectus, Peptostreptococcus micros and Actinomyces israelii.

Results:  93.6% of sampled sites showed bleeding on probing and 23.5% were positive for suppuration. P. intermedia/P. nigrescens, P. gingivalis, and C. rectus were detected in 77.3–85.9% of samples using culture methods and in 85.6–91.3% using immunofluorescence. P. micros and A. actinomycetemcomitans were found, respectively, in 63.3% and 25.0% of all sites using culturing and in 58.7% and 27.7% sites using immunofluorescence. Significantly strong positive associations were observed between T. forsythia and C. rectus (odds ratio 109.46), and T. forsythia and P. gingivalis (odd ratio 90.26), whereas a negative association was seen between P. intermedia/P. nigrescens and A. actinomycetemcomitans (odds ratio 0.42). Coinfection by P. gingivalis, T. forsythia, P. intermedia/P. nigrescens and C. rectus was observed in 62.1% of the test sites, and in 89.4% of the studied subjects. The sensitivity of immunofluorescence for T. forsythia, C. rectus, P. intermedia/P. nigrescens and P. gingivalis was found to be very high (0.99–0.94) using culture as the reference detection method. The agreement between culture and immunofluorescence in detecting the presence or absence of the investigated species was 85.2–88.1% for P. gingivalis, P. intermedia/P. nigrescens, C. rectus, and T. forsythia, 75.9% for A. actinomycetemcomitans and 70.4% for P. micros.

Conclusions:  The microbial profile of the early onset/aggressive periodontitis population was complex. The agreement between the two detection methods was very high.
DNA–DNA relatedness and phylogenetic positions of Slackia exigua, Slackia heliotrinireducens, Eggerthella lenta, and other related bacteria
Authors: Nakazawa F. , Hoshino E.
Published: August 2004

Recently, two asaccharolytic Eubacterium species, Eubacterium exiguum and Eubacterium lentum, and Peptostreptococcus heliotrinreducens have been reclassified as Slackia exigua, Eggerthella lenta and Slackia heliotrinireducens in the novel genera on the basis of 16S rDNA sequence analysis. But DNA–DNA relatedness among these species and other related bacteria have not been reported yet. DNA–DNA relatedness is the standard arbiter and the recommended method for the designation and evaluation of new species, particularly closely related ones. In the present study, DNA–DNA hybridization studies were performed on S. exigua, S. heliotrinireducens and E. lenta together with the other bacterial species in the related genera. The phylogenetic relationships of these species were also investigated by comparison analysis of 16S rDNA sequence data. In the DNA–DNA hybridization studies, S. exigua showed a DNA homology level of 33% to S. heliotrinireducens and 11% to E. lenta. DNA–DNA homology between S. heliotrinireducens and E. lenta was 10%. But these three species showed very low homology (less than 5%) to the related asaccharolytic species such as Eubacterium and Mogibacterium. In conclusion, the DNA–DNA relatedness data together with the evolutionary data in the present paper further support the reclassification of Eubacterium exiguum, Peptostreptococcus heliotrinreducens and Eubacterium lentum as Slackia exigua, Slackia heliotrinireducens and Eggerthella lenta, respectively.
Biofilm growth of Lactobacillus species is promoted by Actinomyces species and Streptococcus mutans
Authors: Filoche S. K. , Anderson S. A. , Sissons C. H.
Published: August 2004

The ability of oral bacteria to integrate within a biofilm is pivotal to their survival. A dependence on the amount of biofilm growth by noncoaggregating Lactobacillus rhamnosus and Lactobacillus plantarum on coculture with Actinomyces naeslundii, Actinomycesgerencseriae, Streptococcus mutans and Veillonella parvula was investigated using an artificial‐mouth culture system. Biofilm formation by the lactobacilli in mono‐culture was poor. In coculture with Actinomyces species the amount of L. rhamnosus increased 7–20 times and L. plantarum 4–7 times compared to its mono‐culture biofilm. S. mutans also promoted substantial biofilm growth of lactobacilli but V. parvula had no effect. We conclude that these Actinomyces species promoted growth of key Lactobacillus species in a biofilm, as did S. mutans to a smaller extent, and that the ability of individual bacteria to form mono‐culture biofilms is not necessarily an indicator of their survival and pathogenic potential in a complex multispecies biofilm community.
In vitro activity of moxifloxacin compared to other antimicrobials against streptococci isolated from iatrogenic oral bacteremia in Spain
Authors: Tomás I. , Álvarez M. , Limeres J. , Otero J. L. , Saavedra E. , López‐Meléndez C. , Diz P.
Published: August 2004

Background/aims:  Systemic dissemination of oral bacteria to distant body sites may be the cause of focal infections. The unsuitable use and overexposure to antimicrobial therapy in clinical dental practice may contribute to the worldwide problem of antimicrobial resistance. The aim of this study was to determine the susceptibilities of streptococci isolated from the bloodstream after dental extractions against penicillin, ampicillin, amoxicillin, erythromycin, clindamycin, and a new fluoroquinolone, moxifloxacin.

Patients and methods:  Eighty‐four patients who required dental extractions were studied. Venous blood samples were collected from each patient at baseline (before dental manipulation) and 30 s after dental extractions. The samples were processed in the Bactec 9240. The isolated bacteria were identified by conventional microbiological techniques. The antimicrobial susceptibility of 81 streptococci was determined by the E‐test method. The NCCLS performance standards were followed.

Results:  88.9–92.5% of the streptococci were sensitive to beta‐lactam agents tested with a minimum inhibitory concentration (MIC)90s ranging from 0.094 to 0.19 mg/l. The resistance to erythromycin and clindamycin was 40.8% (MIC90HR = 256 mg/l) and 21% (MIC90HR = 256 mg/l), respectively. The MIC90 to moxifloxacin was 0.125 mg/l.

Conclusion:  Most of the streptococci isolated from the bloodstream after dental extractions were susceptible in vitro to penicillin, ampicillin, and amoxicillin. The high percentage of streptococci resistant to erythromycin and clindamycin could restrict their usefulness as prophylactic drugs. All the isolates showed a low MIC of moxifloxacin in vitro, making it a promising antimicrobial alternative for the prevention of streptococcal focal infections associated with certain dental manipulations, when the administration of beta‐lactam agents is not indicated.
Diaspora, dispute and diffusion: bringing professional values to the punitive culture of the Poor Law
Authors: Kirby Stephanie
Published: August 2004

From the 1870s to the 1920s Poor Law institutions in England developed from destinations of last resort to significant providers of health‐care. As part of this process a general professionalisation of Poor Law work took place. The change was facilitated by wider social, philosophical and political influences in nineteenth century England. The introduction of trained nurses into the Poor Law was part of a diaspora of both ideas and people from voluntary institutions and organisations. Unrecognised in 1834, nurses eventually became the most numerous class of workhouse officers. This was not accomplished without dispute and acrimony. As a group and as individuals nurses were often at the centre of disputes. Utilising a social history framework and drawing on contemporary written sources, including Poor Law and nursing journals, this paper highlights the role played by Poor Law nurses in the diffusion of values and attitudes that helped to transform the workhouse regime from one of punishment to therapy.
Russian nurses: from the Tsarist Sister of Mercy to the Soviet comrade nurse: a case study of absence of migration of nursing knowledge and skills
Authors: Murray Elizabeth
Published: August 2004

Nursing in Russia during the Tsarist era had no structure and little formal organisation. The typical nurses of the nineteenth century were ‘Sisters of Mercy’, working within the communities of the Orthodox Church and semireligious societies, which were formed to provide a military nursing service. The experience of the Crimean War did not stimulate the foundation of an organised nursing service. There was no transfer of this body of nursing knowledge or experience to the wider rural or civilian population. The majority of Russia's population received inadequate medical and little nursing care.
Heroines of lonely outposts or tools of the empire? British nurses in Britain's model colony: Ceylon, 1878–1948
Authors: Jones Margaret
Published: August 2004

In 1878 two ‘Nightingale’ nurses arrived in the British colony of Ceylon to initiate a training programme for indigenous women in the skills and values of what was then termed ‘scientific nursing’. These two women were the first of a succession of British women who went to the colony to nurse in its hospitals and to train Ceylonese women for the profession. Using the official records of the colonial government held in the National Archives, Kew and the records of the Overseas Nursing Association in the Rhodes House Collection, Oxford, this paper explores both the professional and social experiences of these women. This paper also analyses the role that these representatives of the colonial state played in the development of an indigenous nursing profession and concludes that their presence in the colony ultimately left an ambiguous legacy. In their role as trainers of indigenous women, they furthered the development and spread of a Western nursing profession in the colony's hospitals. At the same time, however, their continuing dominance of training and the positions of responsibility was an inhibiting factor in the ability of indigenous nurses to organise and professionalise. Whereas the doctors, trained in the colony's Medical College, achieved registration as early as 1905, the nurses had to wait until 1949, a year after independence, before their qualification was recognised and protected. Nursing remained throughout the colonial period therefore, even more so than at the metropolitan centre, the ‘Cinderella’ of the medical professions.
Religion, modernity and foreign nurses in Iceland 1896–1930
Authors: Björnsdóttir Kristin , Malchau Susanne
Published: August 2004

This paper describes the influence of foreign nurses upon the development of modern healthcare services and the nursing profession in Iceland in the first three decades of the twentieth century. It represents a case study of how new ideas, traditions and practices migrated between countries and cultures in the twentieth century. Icelandic society was, at that time, still premodern in many ways. Healthcare institutions were almost nonexistent and the means of production were undeveloped. It was into this context that the idea of nursing as a professional activity was introduced. Groups of nurses, the Catholic Sisters of St Joseph of Chambéry and secular nurses, mainly from Denmark, came to the country to organize and provide healthcare services, of which nursing was of central importance. These groups were diasporas, in that they brought traditions and practices from other cultures. The Sisters of St Joseph built, owned and ran the first modern hospital in the country. The Danish nurses introduced nursing as a specialized field of work, in leprosy and tuberculosis nursing and by initiating public health nursing services. They were instrumental in promoting education as an important condition to becoming a nurse, and the development of an Icelandic nursing profession. These nurses were generally respected by the Icelandic people for their contributions and were received with interest and appreciation. The healthcare services introduced by these different groups of nurses reflected modern ways of living and a commitment to professionalism, which involved providing assistance to patients based on the best knowledge available and a philosophy of respect and care.
‘Wanted: 16 nurses of the better educated type’: provision of nurses to South Africa in the late nineteenth and early twentieth centuries
Authors: Sweet Helen
Published: August 2004

This paper is based on research in progress focusing on the histories of mission hospitals in the rural communities of KwaZulu Natal, while also building on earlier research into the pluralism of medical systems within the South African Cape. Sources have been drawn from a range of historical documents, including medical and nursing journals, the archives of a number of medical missionary societies and of the Overseas Nursing Association, but the research has also been informed by oral histories of a broad cross‐section of health professionals who practised in South Africa. A large literature search included a number of biographies and institutional histories. The paper will be divided into three parts — the first provides a brief background to colonialism and the early nursing history of South Africa; the second looks in more detail at the role played by missionary nurses in establishing nursing as a profession and providing training opportunities for African nurses. The final part contrasts missionary nursing with the supply of, and work done by nurses from the Overseas Nursing Association operating within their quite specific, colonial remit. This will show how the two contrasting professional spheres — one reflecting a fairly short‐term commitment, the other, a much broader, ‘vocational’ involvement — may be seen to represent quite different colonial attitudes, and ultimately quite diverse outcomes.
Chinese R&D: naissance, renaissance, or mirage?
Authors: Fischer William A. , Von Zedtwitz Maximilian
Published: August 2004

China's re‐emergence has been treated mostly from economic and political standpoints. This article integrates these perspectives with a review of China's modern history of research and development (R&D). It starts with a brief retrospective of China's efforts in science and technology before the reforms of 1978. It then discusses China's principle R&D issues in the early 1980s and the most significant results of 20 years of rapid industrialization. Based on this historic review and a wide literature analysis, some observations are made about China's R&D capabilities in the first years of the new millennium as well as what challenges may still lie ahead for China before becoming a leading source of scientific and technological innovation.
Organization, programme and structure: an analysis of the Chinese innovation policy framework
Authors: Huang Can , Amorim Celeste , Spinoglio Mark , Gouveia Borges , Medina Augusto
Published: August 2004

The paper first identifies the stakeholders involved in the design and implementation of China's innovation policy and compares them with different government systems in selected Organization for Economic Co‐operation and Development (OECD) countries. In order to disclose the relative strength and weaknesses inside China's innovation policy framework, we proceed to utilize policy practices in the OECD countries as a guideline to examine China's innovation policy in five categories: reform in the public S&T institutions, financial policy, business innovation support structure, human resource policy and legislative actions. Subsequently, several weak components of the Chinese innovation policy framework are identified and two of them are selected for further analysis: education and human resource policy, and protection of Intellectual Property Rights (IPR). Finally, the paper provides some priorities and possible actions for future innovation policy developments in China.
Bartering technology for local resources in exogamic Sino‐foreign joint ventures
Authors: Jolly Dominique R.
Published: August 2004

Five hypotheses were formulated regarding the exogamic nature of Sino‐foreign joint ventures and two propositions regarding incentives for technology transfers and protection against imitation. Research relied on a questionnaire‐based investigation in 67 joint ventures and case studies in various industries. Three lessons were drawn. (1) Each partner contributes with a differentiated set of idiosyncratic and non‐substitutable set of resources; technology is the core contribution of foreign companies no matter which aspect is examined. There is an almost perfect symmetry between the pooled resources and the learning objectives of each partner. (2) Chinese respondents give a strong competitive value to technology transfers. (3) Beyond traditional technical and legal protection, foreign companies slow down imitation with three strategies: taking advantage of time lag; keeping the most creative value added stages at home; playing, not on the technology itself, but on inherent financial or commercial obstacles.
Sequential learning in a Chinese spin‐off: the case of Lenovo Group Limited
Authors: Xie Wei , White Steven
Published: August 2004

This paper analyzes the learning process and sequential capabilities development in Lenovo, China's most successful PC manufacturer, which originated as a spin‐off from a government‐supported research institute. The case study reveals this firm's evolutionary, path‐dependent and stage‐wise progress from initial sales, distribution and service activities to manufacturing, product and process design and, finally developmental R&D. The study shows the interaction among the firm's changing environment, its competitive strategy, and its set of resources and capabilities. The case has implications for research on such organizations, as well as implications for management.
Managing foreign R&D laboratories in China
Authors: Von Zedtwitz Maximilian
Published: August 2004

This paper focuses on the management of R&D units established by foreign companies in China, investigating R&D missions, site build‐up, integration with the parent organization, and overall performance measurement. The research is based on 37 qualitative expert interviews with local R&D directors and managers conducted between 2001 and 2004, using a semi‐structured research questionnaire, and semi‐quantitative research done on 199 foreign R&D labs in China. Cultural influences on R&D management, location advantages, expatriate involvement, and organizational evolution of local laboratories are discussed. We find that foreign R&D laboratories in China are not only important vehicles for local market development but also increasingly important sources of locally developed technology.
R&D in China: an empirical study of Taiwanese IT companies
Authors: Lu Louis Y. Y. , Liu John S.
Published: August 2004

This study extends the research on R&D (research and development) internationalization to a new environmental context (two Asian newly‐industrialized economies, mainland China and Taiwan). Based on a survey of 56 major Taiwanese information technology (IT) companies, the status of R&D internationalization with Taiwan as the home and mainland China as the host is investigated. Human‐capital‐augmentation is found to be the key motive for Taiwanese IT companies to extend R&D activities to the mainland. Accessing capable yet cost effective local engineers with an additional benefit of geographical and linguistic proximity is the major context of this motive. The location decision is based on three considerations – access to engineers, proximity to manufacturing site, and competition avoidance. Finally, three operational patterns of conducting the international design and development (D&D) activities are categorized, which are ‘home‐base‐integration’, ‘host‐base‐integration’, and ‘product life cycle’.