bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth Control of Small-Colony Variants by Genetic Regulation of the Hemin Uptake System
Authors: Roggenkamp Andreas , Hoffmann Harald , Hornef Mathias W. 
Published: March 2004

ABSTRACT

Small-colony variants (SCVs) are slow-growing variants of human bacterial pathogens. They are associated with chronic persistent infections, and their biochemical identification and antimicrobial treatment are impaired by altered metabolic properties. To contribute to the understanding of SCV-mediated infections, we analyzed a clinical SCV isolate derived from a chronic prosthetic hip infection. A sequence analysis of housekeeping genes identified an
Enterobacter hormaechei
-like organism. The SCV phenotype, with growth as microcolonies, was caused by a block within the heme biosynthesis pathway through deletion of the
hemB
locus, as shown by hybridization and complementation experiments. At a low frequency, large-colony variants (LCVs) arose that were dependent on exogenous hemin. To investigate this phenomenon, we cloned and sequenced the 5.8-kb hemin uptake system, denoted
ehu
. Gene expression analysis indicated regulation of this locus in wild-type bacteria by the global iron regulator Fur. Inactivation of Fur in LCVs caused the derepression of
ehu
expression and facilitated bacterial growth. Genetic alterations of the
fur
locus in LCVs were identified as insertions of IS
1A
elements and point mutations. In contrast, SCVs could utilize exogenous hemin only in the absence of iron. Thus, we provide the first molecular characterization of the growth properties of a clinical SCV isolate, which may help to improve the diagnostic and therapeutic management of patients with chronic persistent infections.
Molecular Cloning and Characterization of
cgt
, the
Brucella abortus
Cyclic β-1,2-Glucan Transporter Gene, and Its Role in Virulence
Authors: Roset Mara S. , Ciocchini Andrés E. , Ugalde Rodolfo A. , Iñón de Iannino Nora 
Published: March 2004

ABSTRACT

The animal pathogen
Brucella abortus
contains a gene
cgt
, which complemented
Sinorhizobium meliloti
nodule development (
ndvA
) and
Agrobacterium tumefaciens
chromosomal virulence (
chvA
) mutants. Complemented strains recovered the presence of anionic cyclic β-1,2-glucan, motility, tumor induction in
A. tumefaciens
, and nodule occupancy in
S. meliloti
, all traits strictly associated with the presence of cyclic β-1,2-glucan in the periplasm. Nucleotide sequencing revealed that
B. abortus cgt
contains a 1,797-bp open reading frame coding for a predicted membrane protein of 599 amino acids (65.9 kDa) that is 58.5 and 59.9% identical to
S. meliloti
NdvA and
A. tumefaciens
ChvA, respectively. Additionally,
B. abortus cgt
, like
S. meliloti ndvA
and
A. tumefaciens chvA
possesses ATP-binding motifs and the ABC signature domain features of a typical ABC transporter. Characterization of Cgt was carried out by the construction of null mutants in
B. abortus
2308 and S19 backgrounds. Both mutants do not transport cyclic β-1,2-glucan to the periplasm, as shown by the absence of anionic cyclic glucan, and they display reduced virulence in mice and defective intracellular multiplication in HeLa cells. These results suggest that cyclic β-1,2-glucan must be transported into the periplasmatic space to exert its action as a virulence factor.
Fusobacterium nucleatum
Induces Premature and Term Stillbirths in Pregnant Mice: Implication of Oral Bacteria in Preterm Birth
Authors: Han Yiping W. , Redline Raymond W. , Li Mei , Yin Lihong , Hill Gale B. , McCormick Thomas S. 
Published: March 2004

ABSTRACT

Fusobacterium nucleatum
is a gram-negative anaerobe ubiquitous to the oral cavity. It is associated with periodontal disease. It is also associated with preterm birth and has been isolated from the amniotic fluid, placenta, and chorioamnionic membranes of women delivering prematurely. Periodontal disease is a newly recognized risk factor for preterm birth. This study examined the possible mechanism underlying the link between these two diseases.
F. nucleatum
strains isolated from amniotic fluids and placentas along with those isolated from orally related sources invaded both epithelial and endothelial cells. The invasive ability may enable
F. nucleatum
to colonize and infect the pregnant uterus. Transient bacteremia caused by periodontal infection may facilitate bacterial transmission from the oral cavity to the uterus. To test this hypothesis, we intravenously injected
F. nucleatum
into pregnant CF-1 mice. The injection resulted in premature delivery, stillbirths, and nonsustained live births. The bacterial infection was restricted inside the uterus, without spreading systemically.
F. nucleatum
was first detected in the blood vessels in murine placentas. Invasion of the endothelial cells lining the blood vessels was observed. The bacteria then crossed the endothelium, proliferated in surrounding tissues, and finally spread to the amniotic fluid. The pattern of infection paralleled that in humans. This study represents the first evidence that
F. nucleatum
may be transmitted hematogenously to the placenta and cause adverse pregnancy outcomes. The results strengthen the link between periodontal disease and preterm birth. Our study also indicates that invasion may be an important virulence mechanism for
F. nucleatum
to infect the placenta.
Absence of Interleukin-4 Determines Less Severe Pulmonary Paracoccidioidomycosis Associated with Impaired Th2 Response
Authors: Pina Adriana , Valente-Ferreira Rita C. , Molinari-Madlum Eugênia E. W. , Vaz Celidéia A. C. , Keller Alexandre C. , Calich Vera L. G. 
Published: March 2004

ABSTRACTHost resistance to paracoccidiodomycosis, the main deep mycosis in Latin America, is mainly due to cellular immunity and gamma interferon (IFN-γ) production. To assess the role of interleukin-4 (IL-4), a Th2-inducing cytokine, pulmonary paracoccidioidomycosis was studied in IL-4-deficient (IL-4−/−) and wild-type (WT) C57BL/6 mice at the innate and acquired phases of immune response. Forty-eight hours after infection, equivalent numbers of viableParacoccidioides brasiliensisyeast cells were recovered from the lungs of IL-4−/−and WT mice intratracheally infected with one million fungal cells. Alveolar macrophages from infected IL-4−/−mice controlled in vitro fungal growth more efficiently than macrophages from WT mice and secreted higher levels of nitric oxide. Compared with WT mice, IL-4−/−animals presented increased levels of pulmonary IFN-γ and augmented polymorphonuclear leukocyte influx to the lungs. Decreased pulmonary fungal loads were characterized in deficient mice at week 2 postinfection, concomitant with diminished presence of IL-10. At week 8, lower numbers of yeasts were recovered from lungs and liver of IL-4−/−mice associated with increased production of IFN-γ but impaired synthesis of IL-5 and IL-10. However, a clear shift to a Th1 pattern was not characterized, since IL-4−/−mice did not alter delayed-type hypersensitivity anergy or IL-2 levels. In addition, IL-4 deficiency resulted in significantly reduced levels of pulmonary IL-12, granulocyte-macrophage colony-stimulating factor, IL-3, monocyte chemotactic protein 1, and specific antibody isotypes. In IL-4−/−mice, well-organized granulomas restraining fungal cells replaced the more extensive lesions containing high numbers of fungi and inflammatory leukocytes developed by IL-4-sufficient mice. These results clearly showed that genetically determined deficiency of IL-4 can exert a protective role in pulmonary paracoccidioidomycosis.
MyD88-Deficient Mice Display a Profound Loss in Resistance toMycobacterium tuberculosisAssociated with Partially Impaired Th1 Cytokine and Nitric Oxide Synthase 2 Expression
Authors: Scanga Charles A. , Bafica Andre , Feng Carl G. , Cheever Allen W. , Hieny Sara , Sher Alan 
Published: March 2004

ABSTRACTMycobacterium tuberculosispossesses agonists for several Toll-like receptors (TLRs), yet mice with single TLR deletions are resistant to acute tuberculosis. MyD88−/−mice were used to examine whether TLRs play any role in protection against aerogenicM. tuberculosisH37Rv infection. MyD88−/−mice failed to control mycobacterial replication and rapidly succumbed. Moreover, expressions of interleukin 12, tumor necrosis factor alpha, gamma interferon, and nitric oxide synthase 2 were markedly decreased in the knockout animals. These results argue that resistance toM. tuberculosismust depend on MyD88-dependent signals mediated by an as-yet-undetermined TLR or a combination of TLRs.
Spatiotemporal Analysis of Acid Adaptation-Mediated
Vibrio cholerae
Hyperinfectivity
Authors: Angelichio Michael J. , Merrell D. Scott , Camilli Andrew 
Published: March 2004

ABSTRACT

Acid adaptation has previously been shown to increase the infectivity of
Vibrio cholerae
in the infant mouse model. To better understand this phenomenon, we monitored the spatial distribution and temporal changes in the ratios of acid-adapted cells to unadapted
V. cholerae
cells in the small intestine, as well as the timing of virulence factor expression. We found that the competitive advantage afforded by acid adaptation does not become manifest until greater than 3 h postinfection; thus, acid adaptation does not increase
V. cholerae
passage through the gastric acid barrier. Additionally, acid-adapted and unadapted
V. cholerae
cells colonize the same sections of the small intestine and show similar kinetics of transcriptional induction of the virulence genes
tcpA
and
ctxA.
These studies suggest that the increased infectivity of acid-adapted
V. cholerae
is due to a more rapid onset of multiplication and/or to an increased multiplication rate within the infant mouse intestine.
HLA-A2-Restricted CD8+-Cytotoxic-T-Cell Responses to Novel Epitopes inMycobacterium tuberculosisSuperoxide Dismutase, Alanine Dehydrogenase, and Glutamine Synthetase
Authors: Dong Yuzhi , Demaria Sandra , Sun Xuming , Santori Fabio R. , Jesdale Bill M. , De Groot Anne S. , Rom William N. , Bushkin Yuri 
Published: March 2004

ABSTRACTMajor histocompatibility complex class I-restricted CD8+cytotoxic T lymphocytes (CTL) are implicated in protective Th1 immunity toMycobacterium tuberculosisinfection. We report the identification of three novel HLA-A*0201-restricted CTL epitopes within mycobacterial superoxide dismutase (SodA),l-alanine dehydrogenase (AlaDH), andl-glutamine synthetase (GlnS) proteins.
Glyceraldehyde-3-Phosphate Dehydrogenase of
Streptococcus pneumoniae
Is a Surface-Displayed Plasminogen-Binding Protein
Authors: Bergmann Simone , Rohde Manfred , Hammerschmidt Sven 
Published: March 2004

ABSTRACT

The recruitment of plasminogen endows the bacterial cell surface of
Streptococcus pneumoniae
with proteolytic activity. In this study we demonstrate specific plasmin- and plasminogen-binding activity for the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which is located in the cytoplasm as well as on the surface of pneumococci. GAPDH exhibits a high affinity for plasmin and a significantly lower affinity for plasminogen.
Neutralization of Interleukin-10 Significantly Enhances Gamma Interferon Expression in Peripheral Blood by Stimulation with Johnin Purified Protein Derivative and by Infection withMycobacterium aviumsubsp.paratuberculosisin Experimentally Infected Cattle with Paratuberculosis
Authors: Buza Joram J. , Hikono Hirokazu , Mori Yasuyuki , Nagata Reiko , Hirayama Sachiyo , Bari Abusaleh M. , Shu Yujing , Tsuji Noriko M. , Momotani Eiichi 
Published: March 2004

ABSTRACTMonoclonal antibody neutralization of interleukin-10 (IL-10) increased Johnin purified protein derivative-induced whole-blood gamma interferon (IFN-γ) secretion 23-fold and also increased IFN-γ secretion ninefold following in vitroMycobacterium aviumsubsp.paratuberculosisinfection of peripheral blood mononuclear cells. These results demonstrate the suppressive effect of IL-10 on immune responses toM. aviumsubsp.paratuberculosisinfection in cattle.
Yersinia pseudotuberculosis
Anti-Inflammatory Components Reduce Trinitrobenzene Sulfonic Acid-Induced Colitis in the Mouse
Authors: Marceau Michael , Dubuquoy Laurent , Caucheteux-Rousseaux Christel , Foligne Benoit , Desreumaux Pierre , Simonet Michel 
Published: March 2004

ABSTRACT

Rectal instillation of trinitrobenzene sulfonic acid (TNBS) induces acute colitis in the mouse. We tested the efficacy of
Yersinia pseudotuberculosis
anti-inflammatory components in preventing TNBS-triggered colitis. Animals were orally inoculated with virulence-attenuated
Yersinia
cells (a
phoP
mutant) prior to TNBS administration. Under these experimental conditions, colonic lesions and tumor necrosis factor alpha mRNA levels were significantly reduced.
Adaptation of Diverse Lyme Disease Spirochetes in a Natural Rodent Reservoir Host
Authors: Richter Dania , Klug Birte , Spielman Andrew , Matuschka Franz-Rainer 
Published: March 2004

ABSTRACTWe compared the relative reservoir competence of European wood mice for two genospecies of Lyme disease spirochetes by analyzing susceptibility, intrinsic incubation period, and degree and duration of infectivity.Borrelia afzelii, specializing in particular reservoir hosts, is better adapted to those hosts than is the more generalist genospeciesB. burgdorferisensu stricto.
Evaluation of the reliability of two field hockey specific sprint and dribble tests in young field hockey players
Authors: Lemmink K A P M , Elferink-Gemser M T , Visscher C 
Published: March 2004

Objectives:To determine the reliability of two field hockey specific tests: the shuttle sprint and dribble test (ShuttleSDT) and the slalom sprint and dribble test (SlalomSDT).Methods:The shuttle sprint and dribble performances of 22 young male and 12 young female field hockey players were assessed on two occasions within 4 weeks. Twenty one young female field hockey players took part in the slalom sprint and dribble test twice in a 4 week period.The ShuttleSDT required the players to perform three 30 m shuttle sprints while carrying a hockey stick alternated with short periods of rest and, after a 5 minute rest, three 30 m shuttle sprints alternated with rest while dribbling a hockey ball. The SlalomSDT required the players to run a slalom course and, after a 5 minute rest, to dribble the same slalom with a hockey ball.Results:There were no differences in mean time scores between the two test sessions. The mean differences were small when compared with the means of both test sessions. With the exception of the slalom sprint time, zero lay within the 95% confidence interval of the mean differences indicating that no bias existed between the two measurements. With the exception of delta shuttle time (0.79), all intraclass correlation coefficient values for the ShuttleSDT, met the criterion for reliability of 0.80. Intraclass correlation coefficient values for SlalomSDT were 0.91 for slalom sprint time, 0.78 for slalom dribble time, and 0.80 for delta slalom time.Conclusions:ShuttleSDT and the SlalomSDT are reliable measures of sprint and dribble performances of young field hockey players.
Reliability of a device measuring triceps surae muscle fatigability
Authors: Haber M , Golan E , Azoulay L , Kahn S R , Shrier I 
Published: March 2004

Objective:To examine the test–retest reliability of a protocol using an apparatus designed to standardise the standing heel rise test for the triceps surae muscle.Subjects:40 healthy subjects volunteered to test short and medium term test–retest reliability (group SM, median age 24 years), and a convenience sample of 38 subjects with a history of unilateral deep vein thrombosis (DVT) volunteered to test long term test–retest reliability (group L, median age 52 years).Design:Subjects carried out 23 heel rises per minute until either the pace or the height could no longer be maintained. Group SM subjects repeated the test 30 minutes later (short term), and again 48 hours later (medium term). Subjects in group L did the test on the unaffected leg, and repeated the test one week later (long term).Results:The median number of heel rises achieved per trial in group SM was 34 (range 16 to 120). The intraclass coefficient (ICC) was 0.93 (SEM 2.1) for both 30 minute and 48 hour test–retest reliability. In group L, the median number of heel rises was 27 (range 9 to 97), with ICC 0.88 and SEM 3.4.Conclusions:The apparatus is a simple and inexpensive standardised tool that reliably measures triceps surae fatigability in subjects with no current injury. Future research should assess its use in injured patients.
Effects of leg massage on recovery from high intensity cycling exercise
Authors: Robertson A , Watt J M , Galloway S D R 
Published: March 2004

Background:The effect of massage on recovery from high intensity exercise is debatable. Many studies on massage suffer from methodological flaws such as poor standardisation of previous exercise, lack of dietary control, and inappropriate massage duration.Objective:To examine the effects of leg massage compared with passive recovery on lactate clearance, muscular power output, and fatigue characteristics after repeated high intensity cycling exercise, with the conditions before the intervention controlled and standardised.Methods:Nine male games players participated. They attended the laboratory on two occasions one week apart and at the same time of day. Dietary intake and activity were replicated for the two preceding days on each occasion. After baseline measurement of heart rate and blood lactate concentration, subjects performed a standardised warm up on the cycle ergometer. This was followed by six standardised 30 second high intensity exercise bouts, interspersed with 30 seconds of active recovery. After five minutes of active recovery and either 20 minutes of leg massage or supine passive rest, subjects performed a second standardised warm up and a 30 second Wingate test. Capillary blood samples were drawn at intervals, and heart rate, peak power, mean power, and fatigue index were recorded.Results:There were no significant differences in mean power during the initial high intensity exercise bouts (p  =  0.92). No main effect of massage was observed on blood lactate concentration between trials (p  =  0.82) or heart rate (p  =  0.81). There was no difference in the maximum power (p  =  0.75) or mean power (p  =  0.66) in the subsequent Wingate test, but a significantly lower fatigue index was observed in the massage trial (p  =  0.04; mean (SD) fatigue index 30.2 (4.1)%v34.2 (3.3)%).Conclusions:No measurable physiological effects of leg massage compared with passive recovery were observed on recovery from high intensity exercise, but the subsequent effect on fatigue index warrants further investigation.
Validity and factor structure of the bodybuilding dependence scale
Authors: Smith D , Hale B 
Published: March 2004

Objectives:To investigate the factor structure, validity, and reliability of the bodybuilding dependence scale and to investigate differences in bodybuilding dependence between men and women and competitive and non-competitive bodybuilders.Methods:Seventy two male competitive bodybuilders, 63 female competitive bodybuilders, 87 male non-competitive bodybuilders, and 63 non-competitive female bodybuilders completed the bodybuilding dependence scale (BDS), the exercise dependence questionnaire (EDQ), and the muscle dysmorphia inventory (MDI).Results:Confirmatory factor analysis of the BDS supported a three factor model of bodybuilding dependence, consisting of social dependence, training dependence, and mastery dependence (Q =  3.16, CFI  =  0.98, SRMR  =  0.04). Internal reliability of all three subscales was high (Cronbach’s α  =  0.92, 0.92, and 0.93 respectively). Significant (p<0.001) and moderate correlations were found between all BDS and MDI subscales, and between five of the eight EDQ subscales. A multivariate analysis of covariance, with univariateFtests and Tukey HSD tests, revealed that both male and female competitive bodybuilders scored significantly (p<0.05) higher on all three BDS subscales than the male and female non-competitive bodybuilders. However, there were no significant sex differences on any of the BDS subscales (p>0.05).Conclusion:The three factor BDS appears to be a reliable and valid measure of bodybuilding dependence. Symptoms of bodybuilding dependence are more prevalent in competitive bodybuilders than non-competitive ones, but there are no significant sex differences in bodybuilding dependence.
Comparison of three preventive methods in order to reduce the incidence of ankle inversion sprains among female volleyball players
Authors: Stasinopoulos D 
Published: March 2004

Background:Ankle sprains are the most common form of acute injury in volleyball. A prevention programme consisting of technical training, proprioceptive training, and external support was previously designed to reduce the rate of ankle sprains in volleyball players.Objective:To investigate which of these three interventions is the most effective in preventing ankle sprain in female volleyball players.Methods:Participants were 52 players who suffered ankle sprains during the season 1998–1999. They were divided randomly into three preventive groups: group 1 (n = 18) followed the technical training programme; group 2 (n = 17) followed the proprioceptive programme; group 3 (n = 17) used orthosis. The players followed their respective programmes for the whole of the 1999–2000 season. Data were collected at the end of the season.Results:The three preventive strategies were all effective in preventive further ankle sprain. Technical training was slightly more effective than the other two methods. Orthosis was not effective in athletes who had suffered ankle sprains more than three times during their careers. Under those circumstances, technical training and proprioceptive training were equally effective at preventive further sprains.Conclusions:Technical training and proprioceptive training are effective methods of preventing ankle sprain in volleyball players who have suffered this injury four or more times during their career. Orthosis appears effective only in players with fewer than four previous sprains.
The effect of pre-season dance training on physical indices and back pain in elite cross-country skiers: a prospective controlled intervention study
Authors: Alricsson M , Werner S 
Published: March 2004

Objective:To evaluate the effect of pre-season dance training on back pain, joint mobility, and muscle flexibility, and on speed and agility in elite cross-country skiers.Methods:26 skiers participated (mean (SD) age, 19 (3.9) years). An intervention group (n = 16) had 12 weeks of dance training; a control group (n = 10) did not dance; otherwise both groups followed a similar pre-season physical training programme. Joint mobility and muscle flexibility of the spine, hip, and ankle were measured. Two sports related functional tests (slalom and hurdle) were also done. All measurements/tests were carried out before and after the dancing period.Results:Four (of six) subjects from the intervention group who initially complained of ski related back pain did not report back pain after the dance training; the three subjects with back pain from the control group were unchanged. At study onset the intervention group had a slightly impaired range of motion in the spine compared with the control group. After dance training, there was a better relation between kyphosis of the thoracic spine and lordosis of the lumbar spine, and a 7.1° increase in hip flexion with the knee extended (p = 0.02). In the control group hip extension decreased by 0.08 m on average (p = 0.01). No positive effects of dance training on sports related functional tests were observed.Conclusions:Preseason dance training improved the range of hip motion and joint mobility and the flexibility of the spine. These improvements might explain the reduction in ski related back pain in the intervention group.