bluuebunny/crossref_metadata_2025 huggingface dataset:
Allometric equations for crown fuel biomass of Aleppo pine (Pinus halepensis Mill.) in Greece
Authors: Mitsopoulos I. D. , Dimitrakopoulos A. P.
Published: October 2007

Allometric equations for the estimation of crown fuel weight of Aleppo pine (Pinus halepensis Mill.) trees in the Mediterranean Basin were developed. Forty trees were destructively sampled and their crown fuels were weighed separately for each fuel category. Crown fuel components, both living and dead, were separated into size classes and regression equations that estimate crown fuel load by diameter class were derived. The allometric equation y = axb with diameter at breast height as the single predictor was chosen, because the addition of other parameters did not decrease the residual sum of squares significantly. The adjusted coefficient of determination (R2adj) values were high (R2adj = 0.82–0.88) in all cases. Diameter at breast height was the most significant determinant of crown fuel biomass. The aerial fuels that are consumed during crown fires (i.e. needles and twigs with diameter less than 0.63 cm) comprised 29.3% of the total crown weight. Live fuels constituted ~96.3% of total crown biomass, distributed as follows: needles 16.7% (average load 12.07 kg), branches with 0.0–0.63-cm diameter 12.6% (average load 9.18 kg), 0.64–2.5-cm diameter 37.3% (27.99 kg), 2.51–7.5-cm diameter 25.4% (18.59 kg), and >7.5-cm diameter 3.7% (2.65 kg). The equations provide quantitative fuel biomass attributes for use in crown fire behaviour models, fire management and carbon assessment in Aleppo pine stands.
Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)
Authors: Duguy Beatriz , Alloza José Antonio , Röder Achim , Vallejo Ramón , Pastor Francisco
Published: October 2007

The number of large fires increased in the 1970s in the Valencia region (eastern Spain), as in most northern Mediterranean countries, owing to the fuel accumulation that affected large areas as a consequence of an intensive land abandonment. The Ayora site (Valencia province) was affected by a large fire in July 1979. We parameterised the fire growth model FARSITE for the 1979 fire conditions using remote sensing-derived fuel cartography. We simulated different fuel scenarios to study the interactions between fuel spatial distribution and fire characteristics (area burned, rate of spread and fireline intensity). We then tested the effectiveness of several firebreak networks on fire spread control. Simulations showed that fire propagation and behaviour were greatly influenced by fuel spatial distribution. The fragmentation of large dense shrubland areas through the introduction of wooded patches strongly reduced fire size, generally slowing fire and limiting fireline intensity. Both the introduction of forest corridors connecting woodlands and the promotion of complex shapes for wooded patches decreased the area burned. Firebreak networks were always very effective in reducing fire size and their effect was enhanced in appropriate fuel-altered scenarios. Most firebreak alternatives, however, did not reduce either rate of fire spread or fireline intensity.
Assessing the impact of stand-level harvests on the flammability of forest landscapes
Authors: Palma Cristian D. , Cui Wenbin , Martell David L. , Robak Dario , Weintraub Andres
Published: October 2007

The harvesting of forest stands can reduce landscape flammability by fragmenting fuel continuity in ways that make it difficult for fires to spread and by providing firefighters with fuel discontinuities they can use as anchor points for suppression operations. We describe a methodology for assessing the impact of harvesting designated forest stands on landscape flammability and expected losses. We combine assessments of the probability that fires will be ignited at any point on the landscape with probabilistic predictions concerning how long escaped fires will burn and how they will spread. Shortest path methods are used to identify critical paths that link potential ignition points with values at risk. We then rank stands with respect to their ability to disrupt those critical paths and thereby reduce landscape flammability and fire losses. We describe how we applied our methodology to a 12 964-ha forested area of boreal forest in the province of Alberta, Canada. Our results indicate that the crucial stands in our study area, those that have the most significant impact on landscape flammability and fire loss, tend to be those that are flammable and located on or close to critical paths that link areas where fires are most likely to occur with values at risk.
Fuel and fire characteristics in savanna - woodland of West Africa in relation to grazing and dominant grass type
Authors: Savadogo Patrice , Zida Didier , Sawadogo Louis , Tiveau Daniel , Tigabu Mulualem , Odén Per Christer
Published: October 2007

Fuel characteristics, fire behaviour and temperature were studied in relation to grazing, dominant grass type and wind direction in West African savanna–woodland by lighting 32 prescribed early fires. Grazing significantly reduced the vegetation height, total fuel load, and dead and live fuel fractions whereas plots dominated by perennial grasses had higher values for vegetation height, total fuel load and the quantity of live fuel load. Although fire intensity remained insensitive (P > 0.05) to any of these factors, fuel consumption was significantly (P = 0.021) reduced by grazing, rate of spread was faster in head fire (P = 0.012), and flame length was shorter in head fire than back fire (P = 0.044). The average maximum temperature was higher (P < 0.05) on non-grazed plots, on plots dominated by annual grasses, on plots subjected to head fire, and at the soil surface. Lethal temperature residence time showed a nearly similar trend to fire temperature. Wind speed and total fuel load were best predictors of fire behaviour parameters (R2 ranging from 0.557 to 0.862). It can be concluded that grazing could be used as a management tool to modify fire behaviour, back fire should be carried out during prescribed burning to lower fire severity, and the fire behaviour models can be employed to guide prescribed early fire in the study area.
Abl tyrosine kinases regulate cell–cell adhesion through Rho GTPases
Authors: Zandy Nicole L. , Playford Martin , Pendergast Ann Marie
Published: October 2007

Adherens junctions are calcium-dependent cell–cell contacts that link neighboring cells through cadherin receptors. Coordinated regulation of the actin cytoskeleton by the Rho GTPases is required for the formation and dissolution of adherens junctions. However, the pathways that link cadherin signaling to cytoskeletal regulation remain poorly defined. Here we identify the Abl family kinases as critical mediators of cadherin-mediated adhesion. Endogenous Abl family kinases, Abl and Arg, are activated and required for Rac activation after cadherin engagement and regulate the formation and maintenance of adherens junctions in mammalian cells. Significantly, we show that Abl-dependent regulation of the Rho–ROCK–myosin signaling pathway is critical for the maintenance of adherens junctions. Inhibition of the Abl kinases in epithelial sheets results in the activation of Rho and its downstream target ROCK, leading to enhanced phosphorylation of the myosin regulatory light chain. These signaling events result in enhanced stress fiber formation and increased actomyosin contractility, thereby disrupting adherens junctions. Conversely, Arg gain of function promotes adherens junction formation through a Crk-dependent pathway in cells with weak junctions. These data identify the Abl kinases as a regulatory link between the cadherin–catenin adhesion complex and the actin cytoskeleton through regulation of Rac and Rho during adherens junction formation, and also reveal a functional link between Abl and Rho that is essential for adherens junction stability.
Genomic analysis of human microRNA transcripts
Authors: Saini Harpreet Kaur , Griffiths-Jones Sam , Enright Anton James
Published: October 2007

MicroRNAs (miRNAs) are important genetic regulators of development, differentiation, growth, and metabolism. The mammalian genome encodes ≈500 known miRNA genes. Approximately 50% are expressed from non-protein-coding transcripts, whereas the rest are located mostly in the introns of coding genes. Intronic miRNAs are generally transcribed coincidentally with their host genes. However, the nature of the primary transcript of intergenic miRNAs is largely unknown. We have performed a large-scale analysis of transcription start sites, polyadenylation signals, CpG islands, EST data, transcription factor-binding sites, and expression ditag data surrounding intergenic miRNAs in the human genome to improve our understanding of the structure of their primary transcripts. We show that a significant fraction of primary transcripts of intergenic miRNAs are 3–4 kb in length, with clearly defined 5′ and 3′ boundaries. We provide strong evidence for the complete transcript structure of a small number of human miRNAs.
Recurrent axon collaterals underlie facilitating synapses between cerebellar Purkinje cells
Authors: Orduz David , Llano Isabel
Published: October 2007

Morphological studies have provided ample evidence for synaptic connections between cerebellar Purkinje cells (PCs), but the functional properties of these synapses remain elusive. We report on direct recordings of synaptically connected PCs in mice cerebellar slices. In PCs filled with a fluorescent dye to aid axon visualization and postsynaptic target identification, presynaptic action potentials elicited unitary inhibitory postsynaptic currents in neighboring PCs in 10% of potential connections tested. In 11 pairs, postsynaptic currents had a delay onset of 1.62 ± 0.16 ms with respect to the presynaptic spike, a 10–90% rise time of 2.20 ± 0.33 ms, and a monoexponential decay with a time constant of 13.3 ± 1.7 ms. Average values for peak current and variance-to-mean ratio were 55 ± 14 and 30 ± 3 pA, respectively. In contrast to the depressing nature of the synapse between PCs and deep cerebellar nuclei neurons, PC–PC synapses exhibited strong facilitation operating within a time window of a few milliseconds; paired-pulse ratios for 3- and 20-ms intervals were 1.79 ± 0.18 and 1.01 ± 0.14, respectively (
n
= 6). The facilitation is of presynaptic nature because it is accompanied by a decrease in failure rate. Trains of action potentials evoked in presynaptic varicosities volume-averaged calcium transients whose peak increased 1.7-fold as the frequency increased from 50 to 166 Hz. We suggest that PC–PC synapses are tuned for high fidelity of transmission during bursts of PC activity and that their operation in the cerebellar circuit modulates synchronized PC firing.
Is operative delivery associated with postnatal back pain at eight weeks and eight months? A cohort study
Authors: PATEL ROSHNI R. , PETERS TIM J. , MURPHY DEIRDRE J.
Published: October 2007

Background. Back pain is very common during pregnancy and postnatally, and is a serious cause of morbidity. This research investigates the prevalence of antenatal back pain and the associations between mode of delivery and postnatal back pain at 8 weeks and 8 months. Methods. A prospective population‐based cohort based in Avon, UK. Some 14,663 women were recruited antenatally, due between 1 April 1991 and 31 December 1992. Of these, 12,944 women with singleton, liveborn, term fetuses were included. Self‐reported postal questionnaires were used to assess back pain antenatally and postnatally. The main outcome measures were postnatal back pain at 8 weeks and 8 months. Results. Back pain was very common with a prevalence of 80% at 32 weeks antenatally. Postnatally, back pain affected 68% of women at 8 weeks, and 60% at 8 months. Postnatal back pain was not associated with elective or emergency caesarean section (e.g. adjusted 8 weeks OR: 1.23, 95% CI: 0.89, 1.70, and OR: 0.89, 95% CI: 0.65, 1.22, respectively) nor with assisted versus spontaneous vaginal delivery (OR: 0.99, 95% CI: 0.82, 1.20). Very similar patterns were observed at 8 months. Conclusions. Antenatal and postnatal back pain are common. Elective caesarean section does not protect against postnatal back pain. Neither emergency caesarean section nor assisted vaginal delivery increases the risk of postnatal back pain compared with spontaneous delivery.
FDG‐PET in cervical cancer: staging, re‐staging and follow‐up
Authors: BJURBERG MARIA , KJELLÉN ELISABETH , OHLSSON TOMAS , RIDDERHEIM MONA , BJURBERG MARIA , KJELLÉN ELISABETH , OHLSSON TOMAS , RIDDERHEIM MONA , BRUN EVA
Published: October 2007

Background. Correctly visualising the extent of the disease in cervical cancer is difficult with today's conventional imaging modalities. This paper presents the interim analysis of an on‐going prospective study to evaluate the potential role of FDG‐PET with software fusion with CT images in 3 different clinical settings of cervical cancer. Methods. In Group 1, 10 patients with early stage cervical cancer underwent FDG‐PET 6 months after surgery. Group 2 consisted of 17 patients with locally advanced cervical cancer who underwent FDG‐PET as part of the staging procedure. In Group 3, 12 patients with verified relapse and 3 patients with a strong suspicion thereof underwent FDG‐PET before starting any therapy. The FDG‐PET results were compared with the results of the standard conventional work‐up. All patients had a follow‐up time of at least 6 months. Results. All FDG‐PET scans in Group 1 were true negative. In Group 2, FDG‐PET detected previously unknown locations of metastases in 4 patients, and a synchronous pulmonary carcinoma in 1 patient, resulting in a change in treatment plan for 4 patients. One false negative FDG‐PET result was recorded. In Group 3, FDG‐PET results led to a change in treatment plan for 3 patients. Conclusions. We conclude that FDG‐PET provides crucial information in the pre‐treatment staging procedure in patients with locally advanced or relapsed cervical cancer. However, in the follow‐up of early cervix cancer, FDG‐PET 6 months post‐operatively offered no clinical benefit in this small group of patients.
Vascular endothelial growth factor +936 C/T polymorphism is associated with an increased risk of endometriosis in a Japanese population
Authors: IKUHASHI YOSHIYUKI , YOSHIDA SHIGEKI , KENNEDY STEPHEN , ZONDERVAN KRINA , TAKEMURA NAOYA , DEGUCHI MASASHI , OHARA NORIYUKI , MARUO TAKESHI
Published: October 2007

Background. Vascular endothelial growth factor (VEGF) concentration in endometriosis patients is higher than controls, in serum and ascites, suggesting that VEGF may play an important role in the pathogenesis of endometriosis. In this study, we investigated whether polymorphisms in the VEGF gene are associated with endometriosis in a Japanese population. Methods. Genotyping of VEGF −460 C/T, +405 G/C and +936 C/T polymorphisms were performed in 147 endometriosis cases diagnosed by laparotomy or laparoscopy at a university hospital, and 181 controls, by polymerase chain reaction‐restriction fragment length polymorphism analysis. We compared the genotype distribution and allele frequency of these 3 polymorphisms between endometriosis patients and controls. Results. No significant differences in the frequency and genotype distribution of VEGF −460 C/T, +405 G/C and +936 C/T polymorphisms were found between the endometriosis patients (all disease stages) and controls. However, a positive association was found between stage III–IV disease and the VEGF +936 T allele (p = 0.018). Conclusions. The VEGF +936 T allele is associated with an increased risk of stage III–IV endometriosis in a Japanese population.
First time mothers’ pregnancy and birth experiences varying by age
Authors: ZASLOFF EVA , SCHYTT ERICA , WALDENSTRÖM ULLA
Published: October 2007

Background. The aim of this study was to provide a comprehensive picture of the young to the old first time mother as she presents to the clinician in terms of background, expectations, experiences and outcome of labour. Methods. A longitudinal cohort study was conducted, including 1,302 primiparous women recruited at their first booking visit, at 593 antenatal clinics in Sweden (97% of all clinics), during three 1‐week periods, evenly spread over 1 year in 1999 and 2000. Two questionnaires were posted and completed: in the second trimester and 2 months after the birth. Women were divided into 5 age groups, with women aged 26–29 as reference. Results. The very young women, aged 15–20 years, had the most negative expectations of the upcoming birth. During pregnancy they were more worried and a depressive mood was more common than in the reference group, as were social problems such as unemployment and lack of support. After the birth, they remembered being more afraid and experiencing more pain and lack of control during labour. In spite of this, their overall experience of childbirth did not differ from the reference group. In contrast, the oldest women, aged 35–43 years, did not have negative feelings about the upcoming birth during pregnancy, and did not remember being afraid or experiencing more pain than the reference group, but experienced childbirth overall as more difficult. Only 57% of the oldest women had a normal vaginal delivery compared with 77% of the youngest women. In addition, 7% of the newborns in the oldest group were transferred to the neonatal clinic after the birth, which was almost 3 times as often as in the reference group. Conclusion. This study showed that expectations and experiences of childbirth vary by maternal age. Whereas the youngest women were more exposed to social and psychological problems, which may have affected their expectations and experiences during labour, the oldest women may have suffered from the biological disadvantage of high maternal age, which is associated with a more complicated delivery. When looking back at labour and birth, the youngest women probably felt that the total experience was better than expected, whereas the opposite may have been the case for the oldest group.
Vaginal hysterectomy and oophorectomy in women with 12–20 weeks’ size uterus
Authors: SAHIN YILMAZ
Published: October 2007

Background. To compare the surgical outcomes of vaginal hysterectomy and prophylactic oophorectomy in women with a uterine size<12 weeks’ gestation and 12–20 weeks’ gestation, without decensus. Methods. In this prospective comparative study, 241 consecutive vaginal hysterectomies were planned for women with benign disease of the uterus. All hysterectomies were performed by the same surgeon (author), and divided into 2 groups: a uterine weight >280 g (n = 83, 280–1150 g) and a uterine weight <280 g (n = 158). The 2 groups were compared for success rates of hysterectomy and bilateral oophorectomy vaginally, operative time, change in haemoglobin, haemorrhage, length of hospital stay, operative complications, and febrile morbidity. Results. All 241 hysterectomies were completed successfully vaginally, and no patients required laparotomy or additional procedures in both groups. No significant intra‐ and post‐operative complications requiring admission to the hospital were encountered in either group. Mean operating time was significantly longer in the uteri ≥280‐g group than in the <280‐g group (69.4±24.4 versus 108.2±41.2 min, p<0.0001). The rate of intraoperative haemorrhage (8.43 versus 1.2%) and the change in haemoglobin were significantly higher in the ≥280‐g group compared with the <280‐g group (p<0.01). Significant positive linear correlation between uterine weight and operative time was seen in all 241 hysterectomies (p<0.001). The rate of bilateral oophorectomy was similar between the uteri ≥280‐g group (89.8%) and the <280‐g group (92.9%). The main intraoperative complication of the 241 vaginal hysterectomies was bladder injury that occurred in 1 case (0.4%) in the <280‐g group. There were no statistically significant differences in intra‐ and post‐operative complications, febrile morbidity, and postoperative hospital stay between the groups. Conclusions. Our findings demonstrate that despite the prolonged operating time and increased intraoperative blood loss, vaginal hysterectomy can be safely performed on a large uterus. Routine bilateral prophylactic oophorectomy can be performed in all patients who have sufficiently long infundibulopelvic ligaments to permit removal of the entire ovary.
Oxidative stress markers in pregnant women who snore and fetal outcome: a case control study
Authors: KÖKEN GÜLENGÜL , KIR SAHIN FIGEN , COSAR EMINE , SAYLAN FILIZ , YILMAZ NIGAR , ALTUNTAS IRFAN , FIDAN FATMA , UNLU MEHMET , YILMAZER MEHMET
Published: October 2007

Background. To determine the levels of oxidative stress markers in pregnant women who snore and compare with non‐snoring pregnant women. Fetal outcome of these 2 groups was also evaluated. Materials and methods. Prospective, case control study. Some 40 pregnant women who snored and 43 non‐snoring pregnant women were evaluated. The glutathione peroxidase (GSH‐Px), malondialdehyde (MDA) and myeloperoxidase (MPO) levels of the 2 groups were studied. Infant birthweight, Apgar scores, and other indicators of fetal outcome were obtained. Results. The mean level of GSH‐Px was significantly lower in the pregnant women who snored (p = 0.005), while the mean level of MDA was significantly higher in this group (p = 0.005). Levels of MPO were comparable between the groups (p > 0.05). The pregnant women who snored did not have infants with evidence of an increase in compromised outcome. Conclusion. Although the pregnant women who snored had high levels of MDA, they did not appear to be at increased risk for delivering infants with fetal compromise.
Prostaglandin E2 receptor EP4‐selective antagonist inhibits lipopolysaccharide‐induced cervical ripening in rabbits
Authors: FUKUDA YUKA , SUGIMURA MOTOI , SUZUKI KAZUNAO , KANAYAMA NAOHIRO
Published: October 2007

Background. The purpose of this study was to examine whether EP4 as prostaglandin (PG) E2 receptor is involved in lipopolysaccharide (LPS)‐induced cervical ripening. Methods. New Zealand White non‐pregnant rabbits were randomly allocated to 4 equal groups and treated with vaginal suppositories containing LPS with various concentrations of EP4‐selective antagonist once daily for 3 days, and then sacrificed for analysis. Analysis was performed in order to examine the inhibitory effect of EP4 antagonist on LPS‐induced cervical ripening. The expression of EP4 in a cervix treated with LPS was examined immunohistochemically. The percent of cervical extensibility in the segment of cervix as the tensile strength was determined with 5.8 g of constant perpendicular stretching. The ripening area of the cervix with edematous changes in H&E sections was calculated by a microscopic system with a computer‐assisted digital analyser. Type‐1 collagenase activity was determined in cervical tissue using FITC‐labelled type‐1 collagen. Results. Immunohistochemical study shows the positive staining of EP4 at the interstitial cells in the cervix treated with LPS. The extensibility, cervical edematous area and type‐1 collagenase activity are significantly reduced in the cervix treated with LPS in the presence of EP4 antagonist compared with that treated with LPS alone. Conclusions. These data implicates the EP4 as the PGE2 receptor involved in LPS‐induced cervical ripening.
Increased angiogenesis is associated with poor prognosis of squamous cell carcinoma of the vulva
Authors: NÄYHÄ VEERA V. , STENBÄCK FREJ G.
Published: October 2007

Background. Increased angiogenesis is associated with an increased risk of malignant transformation in many organs. The occurrence, characteristics and significance of angiogenesis in vulvar squamous cell carcinoma are less well known. Methods. In this study, vessel number as well as vessel size, vessel shape and vessel antibody staining intensity were determined in 23,091 vessels in CD34‐stained histological specimens of 42 patients by computer‐assisted quantitative image analysis methods and findings were related to tumor morphology, clinical characteristics and patient survival. Results. The 2‐ and 5‐year survival rates were 81.1 and 64.1%, respectively. High disease stage and high histological grade indicated poor prognosis. In an age‐adjusted multivariate analysis of stage, grade and extent of invasion, these variables compiled a statistically significant prognostic factor (p = 0.001). Tumor histopathological type was a prognostic factor in our study and keratinising tumors did significantly better. Large tumor size, but not depth of invasion, and spray type growth pattern also indicated poor survival. In an age‐adjusted multivariate analysis of stage, grade and extent of invasion, these variables compiled a statistically significant prognostic factor (p = 0.001), but none of these variables alone proved to be an independent prognostic factor. High vessel number and increased vessel size were also significant indicators of poor survival, as were vessel characteristics: vessel number, vessel size, vessel shape and staining intensity together. Conclusion. Increased angiogenesis and altered vessel characteristics were prognostic factors in determining patient survival in this study. Analysis of angiogenesis provided new information on tumor behaviour and provided markers for survival analysis in neoplasms classified by tumor type and growth pattern.
Prosody and its relationship to language in school‐aged children with high‐functioning autism
Authors: McCann Joanne , Peppé Susan , Gibbon Fiona E. , O'Hare Anne , Rutherford Marion
Published: October 2007

Background: Disordered expressive prosody is a widely reported characteristic of individuals with autism. Despite this, it has received little attention in the literature and the few studies that have addressed it have not described its relationship to other aspects of communication.

Aims: To determine the nature and relationship of expressive and receptive language, phonology, pragmatics, and non‐verbal ability in school‐aged children with high‐functioning autism and to determine how prosody relates to these abilities and which aspects of prosody are most affected.

Methods & Procedures: A total of 31 children with high‐functioning autism and 72 typically developing children matched for verbal mental age completed a battery of speech, language, and non‐verbal assessments and a procedure for assessing receptive and expressive prosody.

Outcomes & Results: Language skills varied, but the majority of children with high‐functioning autism had deficits in at least one aspect of language with expressive language most severely impaired. All of the children with high‐functioning autism had difficulty with at least one aspect of prosody and prosodic ability correlated highly with expressive and receptive language. The children with high‐functioning autism showed significantly poorer prosodic skills than the control group, even after adjusting for verbal mental age.

Conclusions: Investigating prosody and its relationship to language in autism is clinically important because expressive prosodic disorders add an additional social and communication barrier for these children and problems are often life‐long even when other areas of language improve. Furthermore, a receptive prosodic impairment may have implications not only for understanding the many functions of prosody but also for general language comprehension.
Expression of biofilm-associated genes of Streptococcus mutans in response to glucose and sucrose
Authors: Shemesh Moshe , Tam Avshalom , Steinberg Doron
Published: October 2007

Streptococcus mutans is known as a primary pathogen of dental caries, one of the most common human infectious diseases. Exopolysaccharide synthesis, adherence to tooth surface and biofilm formation are important physiological and virulence factors of S. mutans. In vitro comparative gene expression analysis was carried out to differentiate 10 selected genes known to be mostly involved in S. mutans biofilm formation by comparing the expression under biofilm and planktonic environments. Real-time RT-PCR analyses indicated that all of the genes tested were upregulated in the biofilm compared to cells grown in planktonic conditions. The influence of simple dietary carbohydrates on gene expression in S. mutans biofilm was tested also. Among the tested genes, in the biofilm phase, the greatest induction was observed for gtf and ftf, which are genes encoding the extracellular polysaccharide-producing enzymes. Biofilm formation was accompanied by a 22-fold induction in the abundance of mRNA encoding glucosyltransferase B (GTFB) and a 14.8 -fold increase in mRNA encoding GTFC. Levels of mRNA encoding fructosyltransferase were induced approximately 11.8-fold in biofilm-derived cells. Another notable finding of this study suggests that glucose affects the expression of S. mutans GS5 biofilm genes. In spite of a significant upregulation in biofilm-associated gene expression in the presence of sucrose, the presence of glucose with sucrose reduced expression of most tested genes. Differential analysis of the transcripts from S. mutans, grown in media with various nutrient contents, revealed significant shifts in the expression of the genes involved in biofilm formation. The results presented here provide new insights at the molecular level regarding gene expression in this bacterium when grown under biofilm conditions, allowing a better understanding of the mechanism of biofilm formation by S. mutans.
Common epitopes in LPS of different Enterobacteriaceae are associated with an immune response against Escherichia coli O157 in bovine serum samples
Authors: Navarro Armando , Eslava Carlos , García de la Torre Guadalupe , León Luis Antonio , Licona Delia , León Lemuel , Zarco Luis Alberto , Cravioto Alejandro
Published: October 2007

Epidemiological studies in both humans and animals conducted in Mexico have shown that the isolation frequency of Escherichia coli O157 : H7 is low. In a previous study, IgG antibodies against E. coli O157, O7 and O116 LPS were found in serum samples from children and adults with no previous history of E. coli O157 : H7 infection. The present study was designed to determine whether a similar immune response against E. coli O157 : H7 and other antigenically related bacteria was present in bovine serum samples. A total of 310 serum samples from different herds in Mexico was analysed by microagglutination assays against different enterobacterial antigens, including E. coli O157. Microagglutination assays were positive against E. coli O7 (55 %), O116 (76 %) and O157 (36 %), Escherichia hermannii (15 %), Salmonella enterica serotype Urbana (14 %) and Salmonella enterica subsp. arizonae (40 %). These results were confirmed using a specific ELISA with purified LPS. A positive reaction was observed against the LPS of E. coli O7 (29 %), O116 (12 %) and O157 (22 %), E. hermannii (4 %), Salmonella Urbana (13 %) and S. enterica subsp. arizonae (12 %). Serum absorption studies of positive serum samples indicated the existence of at least three common epitopes shared by the LPS of E. coli O7, O116 and O157, and two others between E. coli O157 and Salmonella Urbana and S. enterica subsp. arizonae. A bactericidal assay against E. coli O157 : H7 using 31 bovine serum samples was performed, and 22 (71 %) of these serum samples gave positive results. The data demonstrated that bovine serum showed a response against different enterobacteria, including E. coli O157, and that this response could be due to the presence of shared epitopes in the LPS of these organisms.
Tracheobronchitis caused by Aeromonas veronii biovar sobria after near-drowning
Authors: Bossi-Küpfer Mara , Genini Aaron , Peduzzi Raffaele , Demarta Antonella
Published: October 2007

A 19-year-old man developed an acute tracheobronchitis shortly after having been rescued from a near-drowning in a river where previous investigations had demonstrated the presence of 500 c.f.u. ml−1 of Aeromonas sp. in the water. An isolate of Aeromonas veronii biovar sobria was identified as the causative agent of the tracheobronchitis. The causality was supported by the massive growth of A. veronii in bronchial secretion, the presence of a type III secretion system in the bacterial isolate, and the strong haemolytic activity of the strain on blood agar.
Evaluation of the ability of erythromycin-resistant and -susceptible pharyngeal group A Streptococcus isolates from Spain to enter and persist in human keratinocytes
Authors: Oliver Maria A. , García-Rey César , Bosch Rafael , Albertí Sebastián
Published: October 2007

The macrolide-resistance rate among group A Streptococcus (GAS) isolates has increased in some European countries. To investigate the reasons for this increase, the ability of 60 erythromycin-resistant and 61 erythromycin-susceptible, genetically unrelated, pharyngeal GAS isolates from Spain to enter and persist within human keratinocytes was evaluated. It was observed that erythromycin resistance was associated with the presence of prtF1, a gene related to invasiveness, whereas no association was observed with the ability to enter human keratinocytes. However, the ability to enter human keratinocytes was not associated with the presence of prtF1 or with the emm type, suggesting that interaction with keratinocytes depends on several characteristics of the isolate. Almost all strains (95.9 %) were capable of persisting within human keratinocytes. However, most of them (91.7 %) exhibited a decline in viability over time. Interestingly, the ability to persist within keratinocytes protected from the action of the β-lactams was higher among erythromycin-resistant isolates and correlated with their ability to avoid the induction of cellular lysis. These observations suggest that if the carrier state results from intracellular GAS survival, the association between erythromycin resistance and intracellular persistence may represent a serious problem for the eradication of these isolates.
Lactobacillus fermentum Ess-1 with unique growth inhibition of vulvo-vaginal candidiasis pathogens
Authors: Rönnqvist Daniel , Forsgren-Brusk Ulla , Husmark Ulrika , Grahn-Håkansson Eva
Published: October 2007

The aim of this study was to characterize human isolates of Lactobacillus species for their capacity to interfere with the growth of different strains of Candida species in vitro in the search for a potential probiotic. Growth inhibition of Candida species was screened using an agar-overlay method. Inhibiting strains were selected to assay the effect of a cell-free Lactobacillus culture filtrate (LCF) on the growth of isolates of Candida
albicans and Candida
glabrata. A total of 126 human Lactobacillus isolates was investigated. Eighteen isolates significantly inhibited the growth of C. albicans on agar. The LCF of one of these strains showed strong inhibition of both C. albicans and C. glabrata. This strain was genetically identified as Lactobacillus fermentum and designated L. fermentum Ess-1. Further tests to evaluate the probiotic potential of this strain indicated that L. fermentum Ess-1 strain is a promising probiotic for use in clinical trials to treat and prevent vulvo-vaginal candidiasis.
Evidence that the cytolethal distending toxin locus was once part of a genomic island in the periodontal pathogen Aggregatibacter (Actinobacillus) actinomycetemcomitans strain Y4
Authors: Doungudomdacha Sombhun , Volgina Alla , DiRienzo Joseph M.
Published: October 2007

The authors have previously shown that the periodontal pathogen Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans Y4 contains an operon for a genotoxin known as the cytolethal distending toxin (Cdt). The cdt locus in strain Y4 is flanked by remnants of heterologous plasmid and integrase sequences. In this study, the DNA sequence immediately downstream from the cdt locus on the Y4 chromosome was examined. The extended sequence contained a region that had all the characteristics of a typical bacterial pathogenicity or genomic island. The genomic island (GIY4-1) was approximately 22 kb long, was flanked by a bacteriophage attachment (att) sequence and contained a full-length integrase/resolvase gene (xerD). A total of 22 complete and partial ORFs represented putative DNA replication/DNA binding/conjugation proteins as well as hypothetical proteins. GIY4-1 was most closely related to putative genomic islands in Haemophilus ducreyi 35000HP and Haemophilus influenzae 86-028NP and to a chromosomal region in Haemophilus somnus 129PT. GIY4-1 was not present in HK1651, which was used as the prototype strain for genomic sequencing of A. actinomycetemcomitans. Several sequences in GIY4-1 were homologous to ORFs found on the A. actinomycetemcomitans plasmid pVT745. None of the identified ORFs in GIY4-1 appeared to encode potential virulence genes. However, several unique observations supported the possibility that the cdt locus of A. actinomycetemcomitans Y4 was originally contained within the genomic island.
Influence of geographical origin, host animal and stx gene on the virulence characteristics of Escherichia coli O26 strains
Authors: Aktan Ilknur , Carter Ben , Wilking Hendrik , La Ragione Roberto M. , Wieler Lothar , Woodward Martin J. , Anjum Muna F.
Published: October 2007

The influence of geographical origin, host animal and presence of the stx gene on the virulence of Escherichia coli O26 strains from ruminants was determined in this study. A clear association was found between the virulence profile and geographical origin of Shiga-toxigenic E. coli (STEC) O26 strains, with UK STEC O26 strains harbouring virtually identical profiles, whilst central European strains showed considerable heterogeneity in plasmid-encoded genes. The former group were also more likely to be non-motile and katP gene positive. Comparison of UK STEC and atypical enteropathogenic E. coli (aEPEC) O26 strains showed that the presence of the stx1 gene was positively correlated with the presence of espP and katP genes and negatively associated with the presence of the yagP–yagT region and with rhamnose fermentation. In contrast to the uniform profiles of STEC O26 strains from ruminants in the UK, aEPEC O26 strains of bovine and ovine origin showed diverse profiles both within and between groups, and could not be separated into discrete groups. These results indicate that the characteristics of UK O26 strains from ruminants are distinct from those of O26 strains from ruminants and humans in other regions in central Europe. Such differences are expected to influence the zoonotic potential of this pathogen and the subsequent incidence of O26-associated human disease.
Molecular typing divides marine mammal strains of Brucella into at least three groups with distinct host preferences
Authors: Groussaud Pauline , Shankster Stephen J. , Koylass Mark S. , Whatmore Adrian M.
Published: October 2007

In order to investigate the genetic relationships within Brucella isolated from marine mammals, two genome-based typing methods, variable number of tandem repeats (VNTR) typing and multilocus sequence analysis (MLSA), were applied to a selection of 74 marine mammal isolates. All isolates were examined by VNTR and data were compared with multilocus sequencing data from a subset of 48 of these. Marine mammal brucellae are distinct from classically recognized species by these methods and appear to correspond to three major genetic groups, which reflect distinct preferred hosts. One group contains isolates predominantly found in pinnipeds (seals) and corresponds to the previously proposed species ‘Brucella pinnipediae’. However, isolates corresponding to the previously proposed species ‘Brucella cetaceae’ fall into two distinct groups that appear to have different preferred cetacean hosts (porpoises and dolphins). Furthermore, these two groups appear less closely related to each other than either group is to ‘B. pinnipediae’ isolates. The groups identified by VNTR typing and MLSA are completely congruent. The relevance of these findings to current proposals to recognize two species of marine mammal Brucella is discussed.
Multilocus sequence typing of Staphylococcus aureus isolates recovered from cows with mastitis in Brazilian dairy herds
Authors: Rabello Renata F. , Moreira Beatriz M. , Lopes Regina M. M. , Teixeira Lúcia M. , Riley Lee W. , Castro Angela C. D.
Published: October 2007

Staphylococcus aureus is a major pathogen associated with bovine mastitis, one of the most important infectious diseases occurring in dairy cattle herds worldwide. In the present study, S. aureus isolates recovered from cows with mastitis in dairy herds located in the south-east of Brazil were genotyped by PFGE and multilocus sequence typing (MLST). PFGE identified 60 pulsotypes (PTs), which were found to be distributed among six clonal complexes (CCs) by MLST. All PTs with similarity percentages greater than 65 % belonged to the same CC. Most of the PTs belonged to CC126 (n=28) and CC97 (n=19), which were represented by 91 % of the isolates. These CCs have also been recovered from cows with mastitis in countries located in different continents, but they have rarely been isolated from human specimens. Few isolates were represented by PTs belonging to CCs that are frequently isolated from human specimens (CC1, CC5 and CC30). These data reinforce the hypothesis that a limited number of S. aureus CCs are responsible for most bovine mastitis cases internationally. Specific features of the specialized clones should be studied for use as future targets of mastitis control measures.
Species interactions in mixed-community crystalline biofilms on urinary catheters
Authors: Macleod Sarah M. , Stickler David J.
Published: October 2007

Previous experimental investigations of the crystalline biofilms that colonize and block urinary catheters have focussed on their formation by pure cultures of Proteus mirabilis. In the urine of patients undergoing long-term catheterization, P. mirabilis is commonly found in mixed communities with other urinary tract pathogens. Little is known about the effect that the other species have on the rate at which P. mirabilis encrusts catheters. In the present study, a set of data on the nature of the bacterial communities on 106 catheter biofilms has been analysed and it was found that while species such as Providencia stuartii and Klebsiella pneumoniae were commonly associated with P. mirabilis, when Escherichia coli, Morganella morganii or Enterobacter cloacae were present, P. mirabilis was rarely or never found. The hypothesis that the absence of P. mirabilis from some biofilm communities could be due to its active exclusion by other species has also been examined. Experiments in laboratory models showed that co-infection of P. mirabilis with M. morganii, K. pneumoniae or E. coli had no effect on the ability of P. mirabilis to encrust and block catheters. Co-infection with Ent. cloacae or Pseudomonas aeruginosa, however, significantly increased the time that catheters took to block (P <0.05). The growth of Ent. cloacae, M. morganii, K. pneumoniae or E. coli in the model for 72 h prior to superinfection with P. mirabilis significantly delayed catheter blockage. In the case of Ent. cloacae, for example, the mean time to blockage was extended from 28.7 h to 60.7 h (P ≤0.01). In all cases, however, P. mirabilis was able to generate alkaline urine, colonize the biofilms, induce crystal formation and block the catheters. The results suggest that although there is a degree of antagonism between P. mirabilis and some of the other urinary tract organisms, the effects are temporary and whatever the pre-existing urinary microbiota, infection with P. mirabilis is thus likely to lead to catheter encrustation and blockage.
Molecular epidemiology of community-acquired invasive non-typhoidal Salmonella among children aged 2–29 months in rural Gambia and discovery of a new serovar, Salmonella enterica Dingiri
Authors: Ikumapayi Usman N. , Antonio Martin , Sonne-Hansen Jacob , Biney Ekow , Enwere Godwin , Okoko Brown , Oluwalana Claire , Vaughan Adeola , Zaman Syed M. A. , Greenwood Brian M. , Cutts Felicity T. , Adegbola Richard A.
Published: October 2007

Sixty-two invasive non-typhoidal Salmonella (NTS) isolates from children aged 2–29 months in rural Gambia were examined for serovar prevalence and antimicrobial susceptibility, and characterized using multilocus sequence typing (MLST) of seven genes, aroC, dnaN, hemD, hisD, purE, sucA and thrA. Salmonella enterica serovar Enteritidis was the most common serovar (80.6  %), followed by S. enterica serovar Typhimurium (8.0  %). Thirty-three per cent of the isolates were resistant to all eight antimicrobials tested, including ampicillin (74.2  %), cotrimoxazole (64.5  %) and tetracycline (63  %). A total of 40.3  % of the NTS cases had an initial clinical diagnosis of malaria, whilst 27.3  % had a diagnosis of clinical pneumonia and 18  % had a diagnosis of septicaemia. MLST of NTS resulted in ten different sequence types (STs), of which five were novel, representing five different NTS serovars. In general, STs were restricted to the same serovar. One type (ST11) encompassed 80.6  % of the NTSs. A new NTS serovar named S. enterica serovar Dingiri was discovered. S. Dingiri was isolated from a 6-month-old male with an initial clinical diagnosis of malaria but a final clinical diagnosis of anaemia and septicaemia. S. Dingiri, which possesses an antigenic formula of 17:z:1,6, was sensitive to ampicillin, cefotaxime, chloramphenicol, ciprofloxacin, cotrimoxazole and tetracycline but resistant to gentamicin, and was ST338.
A Role for F-Actin in Hexokinase-Mediated Glucose Signaling
Authors: Balasubramanian Rajagopal , Karve Abhijit , Kandasamy Muthugapatti , Meagher Richard B. , Moore Brandon d.
Published: October 2007

HEXOKINASE1 (HXK1) from Arabidopsis (Arabidopsis thaliana) has dual roles in glucose (Glc) signaling and in Glc phosphorylation. The cellular context, though, for HXK1 function in either process is not well understood. Here we have shown that within normal experimental detection limits, AtHXK1 is localized continuously to mitochondria. Two mitochondrial porin proteins were identified as capable of binding to overexpressed HXK1 protein, both in vivo and in vitro. We also found that AtHXK1 can be associated with its structural homolog, F-actin, based on their coimmunoprecipitation from transgenic plants that overexpress HXK1-FLAG or from transient expression assays, and based on their localization in leaf cells after cryofixation. This association might be functionally important because Glc signaling in protoplast transient expression assays is compromised by disruption of F-actin. We also demonstrate that Glc treatment of Arabidopsis seedlings rapidly and reversibly disrupts fine mesh actin filaments. The possible roles of actin in HXK-dependent Glc signaling are discussed.