bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conservation of dynamic localization among MinD and MinE orthologues: oscillation of Neisseria gonorrhoeae proteins in Escherichia coli
Authors: Ramirez‐Arcos Sandra , Szeto Jason , Dillon Jo‐Anne R. , Margolin William 
Published: March 2003

SummaryMin proteins are involved in the correct placement of division septa in many bacterial species. In Escherichia coli (Ec) cells, these proteins oscillate from pole to pole, ostensibly to prevent unwanted polar septation. Here, we show that Min proteins from the coccus Neisseria gonorrhoeae (Ng) also oscillate in E. coli. Green fluorescent protein (GFP) fusions to gonococcal MinD and MinE localized dynamically in different E. coli backgrounds. GFP–MinDNg moved from pole to pole in rod‐shaped E. coli cells with a 70 ± 25 s localization cycle when MinENg was expressed in cis. The oscillation time of GFP–MinDNg was reduced when wild‐type MinENg was replaced with MinENg carrying a R30D mutation, but lengthened by 15 s when activated by MinEEc. Several mutations in the N‐terminal domain of MinDNg, including K16Q and 4‐ and 19‐amino acid truncations, prevented oscillation; these MinDNg mutants showed decreased or lost interaction with themselves and MinENg. Like MinEEc–GFP, MinENg–GFP formed MinE rings and oscillated in E. coli cells when MinDEc was expressed in cis. Finally, in round E. coli cells, GFP–MinDNg appeared to move in a plane parallel to completed septa. This pattern of movement is predicted to be similar in gonococcal cells, which also divide in alternating perpendicular planes.
Evolution of the paralogous hap and iga genes in Haemophilus influenzae: evidence for a conserved hap pseudogene associated with microcolony formation in the recently diverged Haemophilus aegyptius and H. influenzae biogroup aegyptius
Authors: Kilian Mogens , Poulsen Knud , Lomholt Hans 
Published: March 2003

SummaryCertain non‐capsulate strains belonging to the Haemophilus influenzae/Haemophilus aegyptius complex show unusually high pathogenicity, but the evolutionary origin of these virulent phenotypes, termed H. influenzae biogroup aegyptius, is as yet unknown. The aim of the present study was to elucidate the mechanisms of evolution of two paralogous genes, hap and iga, which encode the adhesion and penetration Hap protein and the IgA1 protease respectively. Partial sequencing of hap and iga genes in a comprehensive collection of strains belonging to the H. influenzae/H. aegyptius complex revealed considerable genetic polymorphism and pronounced mosaic‐like patterns in both genes, but no evidence of intrastrain recombination between the two genes. A conserved hap pseudogene was present in all strains of H. aegyptius and H. influenzae biogroup aegyptius, each of which constituted distinct subpopulations as revealed by phylogenetic analysis. There was no evidence for a second, functional copy of the hap gene in these strains. The perturbed expression of the Hap serine protease appears to be associated with the formation of elongated bacterial cells growing in chains and a distinct colonization pattern on conjunctival cells, previously termed microcolony formation. The fact that individual hap pseudogenes differed from the ancestral sequence by zero to two positions within a 1.5 kb stretch suggests that the silencing event happened ≈ 2000–11 000 years ago. Divergence of H. aegyptius and H. influenzae biogroup aegyptius occurred subsequent to this genetic event. The loss of Hap protein expression may be one of the genetic events that facilitated exploitation of the conjunctivae as a new niche.
Linkage disequilibrium between minisatellite loci supports clonal evolution of Mycobacterium tuberculosis in a high tuberculosis incidence area
Authors: Supply Philip , Warren Robin M. , Bañuls Anne‐Laure , Lesjean Sarah , Van Der Spuy Gian D. , Lewis Lee‐Anne , Tibayrenc Michel , Van Helden Paul D. , Locht Camille 
Published: March 2003

SummaryDeciphering the structure of pathogen populations is instrumental for the understanding of the epidemiology and history of infectious diseases and for their control. Although Mycobacterium tuberculosis is the most widespread infectious agent in humans, its actual population structure has remained hypothetical until now because: (i) its structural genes are poorly polymorphic; (ii) adequate samples and appropriate statistics for population genetic analysis have not been considered. To investigate this structure, we analysed the statistical associations (linkage disequilibrium) between 12 independent M. tuberculosis minisatellite‐like loci by high‐throughput genotyping within a model population of 209 isolates representative of the genetic diversity in an area with a very high incidence of tuberculosis. These loci contain variable number tandem repeats (VNTRs) of genetic elements named mycobacterial interspersed repetitive units (MIRUs). Highly significant linkage disequilibrium was detected among the MIRU‐VNTR loci in this model. This linkage disequilibrium was also evident when the MIRU‐VNTR types were compared with the IS6110 restriction fragment length polymorphism types. These results support a predominant clonal evolution of M. tuberculosis.
The spa‐box for transcriptional activation of subtilin biosynthesis and immunity in Bacillus subtilis
Authors: Stein Torsten , Heinzmann Stefan , Kiesau Peter , Himmel Bettina , Entian Karl‐Dieter 
Published: March 2003

SummaryThe subtilin gene cluster (spa) of Bacillus subtilis ATCC 6633 is organized in transcriptional units spaBTC, spaS, spaIFEG and spaRK. Specific binding of the response regulator protein SpaR to spaB, spaS and spaI DNA promoter fragments was shown by means of electromobility shift assays. A repeated pentanucleotide sequence spaced by six nucleotides was identified as SpaR binding motif (spa‐box). Saturating mutational analysis of the spa‐box by single‐ and multiple‐base‐pair substitutions revealed the consensus motif (A/T)TGAT for optimal SpaR binding with the second, third and fifth position being absolutely conservative. Variations in the spacer size between the two pentanucleotide repeats revealed a strong conservation of their relative location. Only DNA with a proximal arrangement of two pentanucleotide repeats showed affinity to SpaR. A 2:1 stoichiometry between SpaR and DNA was obtained by optical biosensor analyses, which corresponds to the binding of two SpaR proteins per spa‐box.
Axe–Txe, a broad‐spectrum proteic toxin–antitoxin system specified by a multidrug‐resistant, clinical isolate of Enterococcus faecium
Authors: Grady Ruth , Hayes Finbarr 
Published: March 2003

SummaryEnterococcal species of bacteria are now acknowledged as leading causes of bacteraemia and other serious nosocomial infections. However, surprisingly little is known about the molecular mechanisms that promote the segregational stability of antibiotic resistance and other plasmids in these bacteria. Plasmid pRUM (24 873 bp) is a multidrug resistance plasmid identified in a clinical isolate of Enterococcus faecium. A novel proteic‐based toxin–antitoxin cassette identified on pRUM was demonstrated to be a functional segregational stability module in both its native host and evolutionarily diverse bacterial species. Induced expression of the toxin protein (Txe) of this system resulted in growth inhibition in Escherichia coli. The toxic effect of Txe was alleviated by co‐expression of the antitoxin protein, Axe. Homologues of the axe and txe genes are present in the genomes of a diversity of Eubacteria. These homologues (yefM–yoeB) present in the E. coli chromosome function as a toxin–antitoxin mechanism, although the Axe and YefM antitoxin components demonstrate specificity for their cognate toxin proteins in vivo. Axe–Txe is one of the first functional proteic toxin–antitoxin systems to be accurately described for Gram‐positive bacteria.
Serotonin type‐4 receptors modulate the sensitivity of intramural mechanoreceptive afferents of the cat rectum
Authors: Schikowski A. , Thewißen M. , Mathis C. , Ross H‐G. , Enck P. 
Published: March 2003

Abstract

It has been suggested that serotonin (5‐hydroxytryptamine) type‐4 (5‐HT4) receptors modulate the sensitivity of intrinsic afferents of the intestinal mucosa. We studied the involvement of 5‐HT4receptors in the modulation of extrinsic afferent sensitivity of the intestinal wall. During distension ramps, mechanoreceptive rectal afferents in sacral dorsal roots were examined in decerebrate anaesthesia‐free cats using the selective 5‐HT4receptor partial agonist, tegaserod (HTF 919), and the 5‐HT4receptor antagonist, SB 203186. The static discharge rate of the afferents evoked by rectal distension decreased after intravenous (i.v.) administration of tegaserod at intraluminal pressures above 30 mmHg, with the most effective reduction occurring at 50 mmHg. The effect was dose‐dependent, with maximal reduction occurring at 1.2 mg kg−1bodyweight, and could be partly reversed by i.v. administration of SB 203186. Tegaserod did not alter the pressure–volume relationship (compliance) of the rectum. It is tentatively concluded that 5‐HT4receptor activation has an inhibitory effect on intramural mechanoreceptors in the cat's rectum. Our results are in line with the observation that tegaserod relieves the sensory symptoms of patients suffering from irritable bowel syndrome.
Immunohistochemical detection of vascular endothelial growth factor (VEGF) in the vasculature of oligodendrogliomas
Authors: Christov  , Christov  , Adle‐Biassette  , Adle‐Biassette  , Le Guerinel  , Le Guerinel  , Natchev  , Gherardi  , Gherardi  
Published: March 2003

C. Christov, H. Adle‐Biassette, C. Le Guerinel, S. Natchev and R. K. Gherardi (1998) Neuropathology and Applied Neurobiology24, 29–35Immunohistochemical detection of vascular endothelial growth factor (VEGF) in the vasculature of oligodendrogliomasVascular endothelial growth factor (VEGF) appears to be implicated in tumour angiogenesis. In the present study immunohistochemical expression of VEGF was evaluated in 34 oligodendrogliomas (13 grade II, 21 grade III [WHO]). VEGF immunoreactivity was found in 31 of 34 cases. Expression of VEGF was observed in endothelial cells and some vascular smooth muscle cells, but not in neoplastic oligodendrocytes. Vessel counts, percentages of VEGF‐positive vessels and vessels with vascular endothelial proliferation were assessed. The degree of VEGF labelling and vascular‐endothelial proliferation in each vessel were evaluated using a 3 degree intensity score. Expression of VEGF was higher in grade III than in grade II oligodendrogliomas as assessed by percentage of VEGF positive vessels (55.8 ± 29.2% vs 17.0 ± 19.0% [P < 0.001]) and by VEGF immunostaining intensity (1.90 ± 0.60 vs 0.90 ± 0.40 [P < 0.001]). VEGF expression did not correlate with vessel density. Intensity of VEGF expression correlated positively with that of vascular‐endothelial proliferation in grade III tumours (r=+0.47 [P < 0.05]). The percentage of VEGF positive vessels showed some degree of positive correlation with the percentage of vessels showing vascular‐endothelial proliferation (r=+408 [P < 0.10]). Within individual grade III tumours 67.5 ± 29.6% of all vessels with vascular‐endothelial proliferation were VEGF‐positive and 31.0 ± 20.5% of all VEGF‐positive vessels showed no evidence of vascular‐endothelial proliferation. We conclude that (i) expression of VEGF is observed in the vasculature of oligodendrogliomas; (ii) marked expression of VEGF is observed in grade III oligodendrogliomas; (iii) VEGF may be one of the interrelated causative stimuli acting in concert to induce vascular‐endothelial proliferation.
Identification of biological/biochemical marker(s) for preterm delivery
Authors: Thorsen Poul , Schendel Diana E. , Deshpande Anjali D. , Vogel Ida , Dudley Donald J. , Olsen Jørn 
Published: March 2003

Fetal and neonatal mortality and morbidity rates are strongly associated with gestational age for delivery: the risk for poor outcome increases as gestational age decreases. Attempts to predict preterm delivery (PTD, spontaneous delivery before 37 weeks’ gestation) have been largely unsuccessful, and rates of PTD have not improved in recent decades. More recently, the reported associations between infections in pregnancy and PTD suggest preventive initiatives that could be taken.The overall objective of the current study is to assess whether specific markers of infection (primarily interleukin (IL) 1β, tumour necrosis factor (TNF) α, IL‐6, and IL‐10) obtained from maternal blood during pregnancy, alone or in combination with other risk factors for PTD, permit identification of women at risk for spontaneous PTD. To achieve this objective, data are obtained from two Danish prospective cohort studies involving serial collection of maternal blood samples, newborn cord blood samples, and relevant confounders and other risk factors for PTD. The first study consists of a completed Danish regional cohort of 3000 pregnant women enrolled in a study of microbiological causes of PTD, upon which a nested case‐control study of PTD in 84 cases and 400 controls has been performed. The second study is a nested case‐control study of 675 PTD cases (equally divided into three gestational age categories of 24–29 weeks’ gestation, 30–33 weeks’ gestation, and 34–36 weeks’ gestation) and 675 controls drawn from the ongoing Danish National Birth Cohort study of 100 000 pregnant women enrolled during 1997–2001. The second study will provide the opportunity to refine and retest hypotheses from the first study, as well as to explore new hypotheses. Our preliminary work suggests that a single predictive marker effectively accounting for a large proportion of PTD is unlikely to be found. Rather, a search for multiple markers indicative of the multifactorial aetiology of PTD is likely to be more successful.Knowledge gained from the proposed studies will be implemented in a third, clinical intervention study against PTD. The first phase of the clinical intervention study will be to establish a risk‐assessment model based on the ‘best’ combination of biological/biochemical measures and other factors associated with PTD in order to identify pregnant women at very high risk of PTD. The second phase will be to apply an intervention model of tailored obstetric care to the very high‐risk pregnant women for PTD identified in phase one. The intervention will be carried out against each specific risk factor associated with PTD identified for the individual. The aim is to reduce the risk for PTD attributed to the combination of risk factors included in the clinical intervention study.
Preterm labour at 34–36 weeks of gestation: should it be arrested?
Authors: Arnon Shmuel , Dolfin Tzipora , Litmanovitz Ita , Regev Rivka , Bauer Sofia , Fejgin Moshe 
Published: March 2003

SummaryCurrently, preterm labour is treated with tocolytic agents and prenatal steroids until the 34th week of gestation only. Our objective in this study was to assess this practice. Seven‐year records of all preterm infants born in our institution at 34–36 weeks of gestation, were evaluated retrospectively. All babies, born in singleton well‐dated pregnancies, without maternal, medical or obstetric complications, and by normal vaginal delivery, were included. Their length of hospital stay and perinatal complications were compared across gestational age groups of 34, 35 and 36 weeks. Of the 207 babies included, statistically significant reductions in the rates of respiratory distress syndrome (15.0% vs. 3.2%), nosocomial sepsis (5.0% vs. 0%) and apnoea of prematurity (11.7% vs. 2.2%), and consequently, in length of hospital stay (16 ± 2.7 vs. 4 ± 0.3 days) occurred between 34 and 36 weeks of gestation. The severity of respiratory distress syndrome also declined significantly. The changes were most noticeable after 35 weeks of gestation, and it was concluded that neonatal complications are still prevalent at 34 and 35 weeks. Therefore, we propose that labour should not be induced at 34 and 35 weeks of gestation and that tocolytic agents and maternal prenatal steroids may be considered in preterm labour during this period.
Psychomotor development in Argentinean children aged 0–5 years
Authors: Lejarraga Horacio , Pascucci María Cecilia , Krupitzky Sara , Kelmansky Diana , Bianco Ana , Martínez Elena , Tibaldi Fabián , Cameron Noel 
Published: March 2003

SummaryIn Argentina, there is no information on ages of attainment of developmental milestones and very few data about environmental factors that influence them. A national survey on the psychomotor development of children under 6 years of age was carried out with the help of 129 paediatricians. Logistic regression was applied to a final sample of 3573 healthy, normal children in order to estimate selected centiles (25th, 50th, 75th and 90th), together with their respective confidence intervals, of the ages of attainment of 78 developmental items belonging to the following areas: personal–social (18 items), fine motor (19), language (18) and gross motor (23). The 50th centile obtained for each of the 43 comparable items was compared with those obtained in previously standardised tests: DDST, Denver II, Bayley and Chilean scales. Neither significant nor systematic differences were found between our results and those described in the tests used for comparison. Multiple logistic regressions showed that social class, maternal education and sex (female) were associated with earlier attainment of some selected developmental items, achieved at ages later than 1 year. Selected items achieved before the first year of life were not affected by any of the independent environmental variables studied. The information is useful in helping paediatricians in their daily practice for surveillance of development, as baseline information for epidemiological studies on development in our country and for cross‐cultural analysis.
Is the timing of exposure to infection a major determinant of acute lymphoblastic leukaemia in Hong Kong?
Authors: Chan Li Chong , Lam Tai Hing , Li Chi Kong , Lau Yu Lung , Li Chi Keung , Yuen Hui Leung , Lee Chi Wai , Ha Shau Yin , Yuen Patrick M. P. , Leung Nai Kong , Patheal Sherry L. , Greaves Mel F. , Alexander Freda E. 
Published: March 2003

SummaryThe hypothesis that protection of infants from exposure to infectious agents with delayed first exposure to one or more specific agents together contribute to the aetiology of childhood leukaemia, especially common acute lymphoblastic leukaemia (cALL), has substantial indirect support from descriptive epidemiology and case–control studies in developed Western countries. A case–control study of childhood leukaemia diagnosed at ages 2–14 years has now been conducted in Hong Kong. Cases (n = 98) formed a consecutive series of Chinese children diagnosed with
acute leukaemia; controls (n = 228) were identified following a survey using random digit dialling and required to attend for medical examination by a paediatrician. Interviews with mothers were conducted in hospital by one trained interviewer using a structured questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) are reported for exposure variables capable of serving as proxies for exposure to infection in two critical time periods: first year of life, year before reference date (diagnosis for cases, corresponding date for controls). Analyses used logistic regression with adjustment for appropriate confounders.Change of area of residence reduced risk if during the first time period (OR = 0.47 [95% CI 0.23, 0.98]) and increased risk if during the second (OR = 3.92, [95% CI 1.47, 10.46]). Reported roseola and/or fever and rash in the first year of life reduced risk (OR = 0.33 [95% CI 0.16, 0.68]) whereas tonsillitis in the period 3–12 months before reference date increased risk (OR = 2.56 [95% CI 1.22, 5.38]). Some other proxies for exposure to infection at the critical times were associated with predicted patterns of risk but day‐care attendance failed to show predicted associations. These results provide support for the delayed exposure hypothesis in an affluent geographical setting in which population exposure to infectious agents is quite distinct from the settings of previous case–control studies.
Impact of low birthweight on subsequent fertility: population‐based register study
Authors: Kristensen Petter , Irgens Lorentz M. , Bjerkedal Tor 
Published: March 2003

SummaryAdverse birth outcomes may influence a family's wish for additional children. We investigated the influence of low birthweight in live births on subsequent fertility, and estimated secular trends of such an effect in a population‐based cohort study of births arranged in consecutive sibship records in the Medical Birth Registry of Norway. We included births of order one to seven to all 587 785 mothers in Norway who had a first singleton birth in 1967–91. Associations between birthweight in 1 158 072 surviving index births of order one to six, 1967–91, and subsequent fertility (probability of another birth), 1967–97, were estimated as fertility ratios in Cox regression analysis. Giving birth to a live infant weighing < 3000 g had a negative effect on subsequent fertility, increasingly strong for decreasing birthweight. Low birthweight (<2500 g) was associated with a fertility ratio of 0.88 [95% confidence interval 0.87, 0.89]. This negative impact was stronger if the mother had also given birth to surviving children of low birthweight previously, particularly if combined with caesarean section in the most recent birth. The negative fertility effect of low birthweight grew slightly stronger between 1967 and ≈ 1980, according to year of first birth. This trend paralleled reduced population fertility in the same period. The moderate negative impact of giving birth to a live infant of low birthweight on subsequent fertility could result from the combination of reduced wish for additional children and biological subfertility.
Infection induces antibodies against the cercarial secretions, but not against the cercarial elastases of Schistosoma mansoni, Schistosoma haematobium, Schistosoma japonicum and Trichobilharzia ocellata
Authors: Bahgat Mahmoud , Francklow Katherine , Doenhoff Michael J. , Li Yong‐Long , Ramzy Reda M.R. , Kirsten Christa , Ruppel Andreas 
Published: March 2003

Cercarial secretions from different species of the parasite Schistosoma and from Trichobilharzia ocellata contain a proteolytic activity, cercarial elastase, which was demonstrated by a 30 kDa band in gelatin gels. Sera of patients infected with Schistosoma mansoni, Schistosoma haematobium or Schistosoma japonicum contain immunoglobulin G which react in ELISA with cercarial secretions from all schistosomes and cross‐react among the different parasite species. In Western blots, however, infection sera from patients, as well as heavily infected mice or rabbits, did not react with a 30‐kDa protein. Moreover, when sections from infected snails (Biomphalaria, Bulinus and Lymnaea) were analysed by immunofluorescence using the same infection sera, only the tegument of the developing cercariae was recognized, but not the acetabular glands. In contrast, when antisera against purified cercarial elastase from either S. mansoni or S. haematobium were tested with sections of infected Biomphalaria or Bulinus, fluorescence was strong in the preacetabular glands of the cercariae of either species, but undetectable with the tegument. Cross‐reactivity of both antisera extended to T. ocellata‐infected Lymnaea, but not to S. japonicum‐infected Oncomelania. In conclusion, although immunization with purified cercarial elastase results in antibody production, the enzyme does not induce an apparent antibody response following natural infection.