bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of marathon running on cardiac structure and function in recreational runners
Authors: WHYTE Gregory , GEORGE Keith , SHAVE Robert , DAWSON Ellen , STEPHENSON Claire , EDWARDS Ben , GAZE David , OXBOROUGH David , FORSTER Jan , SIMSPON Rickie 
Published: December 2004

The present study examined the relationship between LV (left ventricular) function, markers of cardiac-specific damage and markers of oxidative stress in recreational runners following a marathon. Runners (n=52; 43 male and nine female; age, 35±10 years; height, 1.74±0.08 m; body mass, 75.9±8.9 kg) were assessed pre- and immediately post-marathon. LV function was assessed using standard M-mode two-dimensional Doppler echocardiography and TDI (tissue-Doppler imaging) echocardiography. Serum was analysed for cTnT (cardiac troponin-T), TEAC (Trolox equivalent antioxidant capacity; a measure of total antioxidant capacity), MDA (malondealdehyde) and 4-HNE (4-hydroxynonenal). A strong relationship was observed between standard and TDI echocardiography for all functional measures. Diastolic function was altered post-marathon characterized by a reduction in E (peak early diastolic filling: 0.79±0.11 compared with 0.64±0.16 cm/s; P&lt;0.001), an increase in A (peak late diastolic filling: 0.48±0.11 compared with 0.60±0.12 cm/s; P&lt;0.001) and a resultant decrease in E/A (ratio of E to A; 1.71±0.48 compared with 1.10±0.31; P&lt;0.001). Ejection fraction remained unchanged post-marathon. Thirty-two runners presented with cTnT values above the lower limit of detection for the assay (0.01 μg/l), and 20 runners presented post-marathon with cTnT values above the acute myocardial infarction cut-off value (0.05 μg/l). No significant correlations were observed between cTnT and any functional measurements. MDA (2.90±1.58 compared with 3.59±1.47 μmol/l) and TEAC (1.80±0.12 compared with 1.89±0.21 mmol/l) were significantly increased post-marathon, but were unrelated to changes in function or cTnT. In conclusion, the present study demonstrated a reduction in diastolic function and widespread evidence of minimal cardiac damage following a marathon in recreational runners. The mechanism(s) underpinning the altered function and appearance of cTnT appear unrelated to reactive oxygen species.
Evidence for fetal programming of obesity with a focus on putative mechanisms
Authors: Wild Sarah H. , Byrne Christopher D. 
Published: December 2004

AbstractObesity is associated with insulin resistance, the metabolic syndrome (a clustering of three or more of increased waist circumference, blood pressure, fasting glucose and fasting plasma triacylglycerol levels and reduced HDL levels), and a marked increase in the risk of type 2 diabetes and CHD. The impact of obesity differs between individuals, particularly between men and women and between ethnic groups. For example, in South Asians, although overall obesity is less prevalent, central obesity and the metabolic syndrome are more prevalent than in Europeans and this pattern is associated with the development of type 2 diabetes and CHD at an earlier age. It is important to examine individual risk factors contributing to obesity because they may have a different impact in population subgroups. Many factors contribute to the aetiology of obesity and there is increasing evidence to suggest that altered early development is one such factor and is associated with abnormal fat accumulation, the metabolic syndrome and type 2 diabetes in later life. The present review presents this evidence and discusses some of the mechanisms that may be involved in the pathogenesis of the programming of obesity.
The application of a monoclonal antibody to CD62L on paraffin‐embedded tissue samples in the assessment of the cutaneous T‐cell infiltrates
Authors: Magro Cynthia M. , Sachdeva Mandi P. , Crowson A. Neil , Barusevicius Alan , Baran Peter N. , Kovatich Albert J. 
Published: December 2004

Background:  A reduction in the expression of the pan T‐cell markers CD7 and CD62L supports an endogenous T‐cell dyscrasia. Previously, clone availability for CD62L restricted its application to frozen tissue sections.Materials and methods:  A nonavidin/biotin technique to examine CD3, CD62L, and CD7 in paraffin formalin‐fixed tissue in non‐neoplastic and neoplastic T‐cell infiltrates.Results:  In the reactive group, CD62L manifested a 15 and 22% reduction in epidermal and dermal staining, respectively; there was a 42 and 31% reduction in epidermal and dermal CD7 staining. In lymphomatoid hypersensitivity, CD62L showed a 24 and 9% reduction in epidermal and dermal staining, respectively; CD7 staining demonstrated reduced staining by 70 and 66% in the epidermis and dermis. In the non‐lymphomatous endogenous T‐cell dyscrasia and lymphoma categories, an 80% diminution in CD62L and CD7 expression was seen.Conclusions:  CD62L can be successfully applied in formalin‐fixed tissue and exhibits enhanced specificity compared to CD7 in the evaluation of cutaneous T‐cell infiltrates. Both CD62L and CD7 in paraffin‐embedded, formalin‐fixed tissue are useful diagnostic adjuncts, especially in regard to the discrimination of lymphomatoid hypersensitivity reactions from true endogenous T‐cell dyscrasia.
Cutaneous carcinosarcoma: adnexal vs. epidermal types define high‐ and low‐risk tumors. Results of a meta‐analysis
Authors: Tran Tien Anh , Muller Sigfrid , Chaudahri Prakash J. , Carlson J. Andrew 
Published: December 2004

Objective:  We report four cases of cutaneous carcinosarcoma (CS) and perform a meta‐analysis of the cutaneous CS literature.Results:  CS occurred in elderly patients (mean of 80 years) on sun‐damaged skin, and were keratotic papules of short duration. They did not recur after excision. CS exhibited basal cell carcinoma mixed with atypical fibroxanthoma cell populations. Immunophenotyping revealed vimentin+/keratin– spindle cells and vimentin–/keratin+ epithelial cells. Three cases exhibited p53 protein expression of both carcinomatous and sarcomatous components. Literature review identified 38 cases of cutaneous CS that could be broadly classified into two distinct groups. Epidermal‐derived (basal or squamous cell carcinoma epithelial component) CS arose on the sun‐damaged skin of the head and neck of elderly males (mean age 72 years) and had a 70% 5‐year disease‐free survival. In contrast, adnexal CS (spiradenocarcinoma, porocarcinoma, proliferating tricholemmal cystic carcinoma, or matrical carcinoma) occurred in younger patients (mean age 58 years), showed recent growth in a long‐standing nodule and had a 25% 5‐year disease‐free survival. Age less than 65 years, recent growth, long‐standing skin tumor, and tumor size greater than 2 cm significantly correlated with poor outcome.Conclusions:  Cutaneous CS is an aggressive skin cancer with high risk for advanced disease. Significant risk factors exist whose identification will allow for better management of CS patients.
A Sensor of the Two-Component System CpxA Affects Expression of the Type III Secretion System through Posttranscriptional Processing of InvE
Authors: Mitobe Jiro , Arakawa Eiji , Watanabe Haruo 
Published: December 2004

ABSTRACT

The chief function of the Cpx two-component system is perceiving various cell envelope stresses, but CpxR is also known to regulate the expression of the type III secretion system (TTSS) of
Shigella sonnei
through transcription of the primary regulator
virF
. Here, we have isolated novel
cpxA
mutants that exhibited decreased TTSS expression from
Escherichia coli
HW1273, which carries the virulence plasmid of
S. sonnei
. The
cpxA
deletion strain of HW1273 expressed β-galactosidase activity levels from the
virF-lacZ
fusion similar to those of HW1273. However, the second regulator InvE (VirB) and the TTSS component IpaB proteins were apparently expressed at a low level. In the
cpxA
strain, β-galactosidase activity levels from the
invE-lacZ
transcriptional fusion remained similar to those of HW1273, whereas the β-galactosidase activity level from the translational fusion of
invE-lacZ
was reduced to 21% of that of HW1273. Therefore, the deletion of the
cpxA
gene influenced TTSS expression chiefly at the posttranscriptional processing of InvE. In addition, the
cpxA
deletion strain of
S. sonnei
showed the same phenotype. These results indicate that the Cpx two-component system is involved in virulence expression through posttranscriptional processing of the regulatory protein InvE, a novel feature of the Cpx two-component system in posttranscriptional processing and virulence expression of
Shigella
.
Identification and Characterization of a Regulatory Sequence Recognized by
Mycobacterium tuberculosis
Persistence Regulator MprA
Authors: He Hongjun , Zahrt Thomas C. 
Published: December 2004

ABSTRACT

Establishment and maintenance of persistent, latent infection by
Mycobacterium tuberculosis
are dependent on expression of the
mprA-mprB
regulatory system. Previously, MprA and MprB were shown to participate in phosphotransfer reactions characteristic of two-component signaling systems. To begin identifying downstream effector genes regulated by
mprA-mprB
during persistent stages of infection, a search for the regulatory sequence(s) recognized by response regulator MprA was carried out. Here, evidence is presented demonstrating that MprA recognizes a 19-bp sequence comprising two loosely conserved 8-bp direct repeat subunits separated by 3 nucleotides. This motif, termed the MprA box, is found upstream of the
mprA
coding sequence and that of downstream gene
pepD
(
Rv0983
). Protein phosphorylation was not required for binding to this DNA sequence by MprA in vitro; however, phosphorylation enhanced DNA binding by MprA and was required for the regulation of
mprA
and
pepD
by MprA in vivo. Binding of MprA to the MprA box was dependent on conserved nucleotides contained within repeat subunits and on the spacer length separating these repeats. In addition, recognition of this sequence proceeded via tandem binding of two monomers of MprA. Identification of the genetic determinants regulated by MprA will ultimately enhance our understanding of the mechanisms utilized by
M. tuberculosis
to undergo latency.
Inactivation of
swmA
Results in the Loss of an Outer Cell Layer in a Swimming
Synechococcus
Strain
Authors: McCarren J. , Heuser J. , Roth R. , Yamada N. , Martone M. , Brahamsha B. 
Published: December 2004

ABSTRACT

The mechanism of nonflagellar swimming of marine unicellular cyanobacteria remains poorly understood. SwmA is an abundant cell surface-associated 130-kDa glycoprotein that is required for the generation of thrust in
Synechococcus
sp. strain WH8102. Ultrastructural comparisons of wild-type cells to a mutant strain in which the gene encoding SwmA has been insertionally inactivated reveal that the mutant lacks a layer external to the outer membrane. Cryofixation and freeze-substitution are required for the preservation of this external layer. Freeze fracturing and etching reveal that this additional layer is an S-layer. How the S-layer might function in motility remains elusive; however, this work describes an ultrastructural component required for this unique type of swimming. In addition, the work presented here describes the envelope structure of a model swimming cyanobacterium.
The Elastic Properties of the
Caulobacter crescentus
Adhesive Holdfast Are Dependent on Oligomers of
N
-Acetylglucosamine
Authors: Li Guanglai , Smith Christopher S. , Brun Yves V. , Tang Jay X. 
Published: December 2004

ABSTRACT

The aquatic bacterium
Caulobacter crescentus
attaches to solid surfaces through an adhesive holdfast located at the tip of its polar stalk, a thin cylindrical extension of the cell membrane. In this paper, the elastic properties of the
C. crescentus
stalk and holdfast assembly were studied by using video light microscopy. In particular, the contribution of oligomers of
N
-acetylglucosamine (GlcNAc) to the elasticity of holdfast was examined by lysozyme digestion.
C. crescentus
cells attached to a surface undergo Brownian motion while confined effectively in a harmonic potential. Mathematical analysis of such motion enabled us to determine the force constant of the stalk-holdfast assembly, which quantifies its elastic properties. The measured force constant exhibits no dependence on stalk length, consistent with the theoretical estimate showing that the stalk can be treated as a rigid rod with respect to fluctuations of the attached cells. Therefore, the force constant of the stalk-holdfast assembly can be attributed to the elasticity of the holdfast. Motions of cells in a rosette were found to be correlated, consistent with the elastic characteristics of the holdfast. Atomic force microscopy analysis indicates that the height of a dried (in air) holdfast is approximately one-third of that of a wet (in water) holdfast, consistent with the gel-like nature of the holdfast. Lysozyme, which cleaves oligomers of GlcNAc, reduced the force constant to less than 10% of its original value, consistent with the polysaccharide gel-like nature of the holdfast. These results also indicate that GlcNAc polymers play an important role in the strength of the holdfast.
Transcriptional Control by A-Factor of Two Trypsin Genes in
Streptomyces griseus
Authors: Kato Jun-ya , Chi Won-Jae , Ohnishi Yasuo , Hong Soon-Kwang , Horinouchi Sueharu 
Published: December 2004

ABSTRACT

AdpA is the key transcriptional activator for a number of genes of various functions in the A-factor regulatory cascade in
Streptomyces griseus
, forming an AdpA regulon. Trypsin-like activity was detected at a late stage of growth in the wild-type strain but not in an A-factor-deficient mutant. Consistent with these observations, two trypsin genes,
sprT
and
sprU
, in
S. griseus
were found to be members of the AdpA regulon; AdpA activated the transcription of both genes by binding to the operators located at about −50 nucleotide positions with respect to the transcriptional start point. The transcription of
sprT
and
sprU,
induced by AdpA, was most active at the onset of sporulation. Most trypsin activity exerted by
S. griseus
was attributed to SprT, because trypsin activity in an
sprT
-disrupted mutant was greatly reduced but that in an
sprU
-disrupted mutant was only slightly reduced. This was consistent with the observation that the amount of the
sprT
mRNA was much greater than that of the
sprU
transcript. Disruption of both
sprT
and
sprU
(mutant Δ
sprTU
) reduced trypsin activity to almost zero, indicating that no trypsin genes other than these two were present in
S. griseus
. Even the double mutant Δ
sprTU
grew normally and developed aerial hyphae and spores over the same time course as the wild-type strain.
Role of the Two Catalytic Domains of DSR-E Dextransucrase and Their Involvement in the Formation of Highly α-1,2 Branched Dextran
Authors: Fabre Emeline , Bozonnet Sophie , Arcache Audrey , Willemot René-Marc , Vignon Michel , Monsan Pierre , Remaud-Simeon Magali 
Published: December 2004

ABSTRACT

The
dsrE
gene from
Leuconostoc mesenteroides
NRRL B-1299 was shown to encode a very large protein with two potentially active catalytic domains (CD1 and CD2) separated by a glucan binding domain (GBD). From sequence analysis, DSR-E was classified in glucoside hydrolase family 70, where it is the only enzyme to have two catalytic domains. The recombinant protein DSR-E synthesizes both α-1,6 and α-1,2 glucosidic linkages in transglucosylation reactions using sucrose as the donor and maltose as the acceptor. To investigate the specific roles of CD1 and CD2 in the catalytic mechanism, truncated forms of
dsrE
were cloned and expressed in
Escherichia coli
. Gene products were then small-scale purified to isolate the various corresponding enzymes. Dextran and oligosaccharide syntheses were performed. Structural characterization by
13
C nuclear magnetic resonance and/or high-performance liquid chromatography showed that enzymes devoid of CD2 synthesized products containing only α-1,6 linkages. On the other hand, enzymes devoid of CD1 modified α-1,6 linear oligosaccharides and dextran acceptors through the formation of α-1,2 linkages. Therefore, each domain is highly regiospecific, CD1 being specific for the synthesis of α-1,6 glucosidic bonds and CD2 only catalyzing the formation of α-1,2 linkages. This finding permitted us to elucidate the mechanism of α-1,2 branching formation and to engineer a novel transglucosidase specific for the formation of α-1,2 linkages. This enzyme will be very useful to control the rate of α-1,2 linkage synthesis in dextran or oligosaccharide production.
Timing and Localization of Rhamnolipid Synthesis Gene Expression in
Pseudomonas aeruginosa
Biofilms
Authors: Lequette Yannick , Greenberg E. P. 
Published: December 2004

ABSTRACT

Pseudomonas aeruginosa
biofilms can develop mushroom-like structures with stalks and caps consisting of discrete subpopulations of cells. Self-produced rhamnolipid surfactants have been shown to be important in development of the mushroom-like structures. The quorum-sensing-controlled
rhlAB
operon is required for rhamnolipid synthesis. We have introduced an
rhlA-gfp
fusion into a neutral site in the
P. aeruginosa
genome to study
rhlAB
promoter activity in rhamnolipid-producing biofilms. Expression of the
rhlA-gfp
fusion in biofilms requires the quorum-sensing signal butanoyl-homoserine lactone, but other factors are also required for expression. Early in biofilm development
rhlA-gfp
expression is low, even in the presence of added butanoyl-homoserine lactone. Expression of the fusion becomes apparent after microcolonies with a depth of >20 μm have formed and, as shown by differential labeling with
rfp
or fluorescent dyes,
rhlA-gfp
is preferentially expressed in the stalks rather than the caps of mature mushrooms. The
rhlA-gfp
expression pattern is not greatly influenced by addition of butanoyl-homoserine lactone to the biofilm growth medium. We propose that rhamnolipid synthesis occurs in biofilms after stalks have formed but prior to capping in the mushroom-like structures. The differential expression of
rhlAB
may play a role in the development of normal biofilm architecture.
Localization of MreB inRhodobacter sphaeroidesunder Conditions Causing Changes in Cell Shape and Membrane Structure
Authors: Slovak Peter M. , Wadhams George H. , Armitage Judith P. 
Published: December 2004

ABSTRACTMreB is thought to be a bacterial actin homolog that defines the morphology of rod-shaped bacteria.Rhodobacter sphaeroideschanges shape, from a rod to coccobacillus, and undergoes extensive cytoplasmic membrane invagination when it switches from aerobic to photoheterotrophic growth. The role of MreB in definingR. sphaeroidesshape was therefore investigated. Attempts at deleting or insertionally inactivatingmreBwere unsuccessful under all growth conditions. Immunofluorescence microscopy showed MreB localized to mid-cell in elongating cells under both aerobic and photoheterotrophic conditions. Three-dimensional reconstruction showed that MreB formed a ring at mid-cell. MreB remained at mid-cell as septation began but localized to new sites in the daughter cells before the completion of septation. MreB localized to putative septation sites in cephalexin-treated filamentous cells. Genomic single-copymreBwas replaced withgfp-mreB, and green fluorescent protein (GFP)-MreB localized in the same pattern, as seen with immunofluorescence microscopy. Some of the cells expressing GFP-MreB were abnormal, principally displaying an increase in cell width, suggesting that the fusion was not fully functional in all cells. GFP-MreB localized to swellings at mid-cell in cells treated with the penicillin-binding protein 2 inhibitor amdinocillin. These data suggest that MreB is essential inR. sphaeroides, performing a role at mid-cell in elongating cells, and in early septation, putatively in the cytoplasmic control of the peptidoglycan synthetic complexes.
Comparative Analysis of the Development of Swarming Communities ofBacillus subtilis168 and a Natural Wild Type: Critical Effects of Surfactin and the Composition of the Medium
Authors: Julkowska Daria , Obuchowski Michal , Holland I. Barry , Séror Simone. J. 
Published: December 2004

ABSTRACTThe natural wild-typeBacillus subtilisstrain 3610 swarms rapidly on the synthetic B medium in symmetrical concentric waves of branched dendritic patterns. In a comparison of the behavior of the laboratory strain 168 (trp) on different media with that of 3610, strain 168 (trp), which does not produce surfactin, displayed less swarming activity, both qualitatively (pattern formation) and in speed of colonization. On E and B media, 168 failed to swarm; however, with the latter, swarming was arrested at an early stage of development, with filamentous cells and rafts of cells (characteristic of dendrites of 3610) associated with bud-like structures surrounding the central inoculum. In contrast, strain 168 apparently swarmed efficiently on Luria-Bertani (LB) agar, colonizing the entire plate in 24 h. However, analysis of the intermediate stages of development of swarms on LB medium demonstrated that, in comparison with strain 3610, initiation of swarming of 168 (trp) was delayed and the greatly reduced rate of expansion of the swarm was uncoordinated, with some regions advancing faster than others. Moreover, while early stages of swarming in 3610 are accompanied by the formation of large numbers of dendrites whose rapid advance involves packs of cells at the tips, strain 168 advanced more slowly as a continuous front. Whensfp+was inserted into the chromosome of 168 (trp) to reestablish surfactin production, many features observed with 3610 on LB medium were now visible with 168. However, swarming of 168 (sfp+) still showed some reduced speed and a distinctive pattern compared to swarming of 3610. The results are discussed in terms of the possible role of surfactin in the swarming process and the different modes of swarming on LB medium.
Identification of an Amino Acid Position That Determines the Substrate Range of Integral Membrane Alkane Hydroxylases
Authors: van Beilen Jan B. , Smits Theo H. M. , Roos Franz F. , Brunner Tobias , Balada Stefanie B. , Röthlisberger Martina , Witholt Bernard 
Published: December 2004

ABSTRACT

Selection experiments and protein engineering were used to identify an amino acid position in integral membrane alkane hydroxylases (AHs) that determines whether long-chain-length alkanes can be hydroxylated by these enzymes. First, substrate range mutants of the
Pseudomonas putida
GPo1 and
Alcanivorax borkumensis
AP1 medium-chain-length AHs were obtained by selection experiments with a specially constructed host. In all mutants able to oxidize alkanes longer than C
13
, W55 (in the case of
P. putida
AlkB) or W58 (in the case of
A. borkumensis
AlkB1) had changed to a much less bulky amino acid, usually serine or cysteine. The corresponding position in AHs from other bacteria that oxidize alkanes longer than C
13
is occupied by a less bulky hydrophobic residue (A, V, L, or I). Site-directed mutagenesis of this position in the
Mycobacterium tuberculosis
H37Rv AH, which oxidizes C
10
to C
16
alkanes, to introduce more bulky amino acids changed the substrate range in the opposite direction; L69F and L69W mutants oxidized only C
10
and C
11
alkanes. Subsequent selection for growth on longer alkanes restored the leucine codon. A structure model of AHs based on these results is discussed.