bluuebunny/crossref_metadata_2025_split huggingface dataset:
The exbD gene of Photorhabdus temperata is required for full virulence in insects and symbiosis with the nematode Heterorhabditis
Authors: Watson Robert J. , Joyce Susan A. , Spencer Georgette V. , Clarke David J. 
Published: April 2005

Summary Photorhabdus are bacteria found colonizing the gut of a specialized stage of the nematode Heterorhabditis, called the infective juvenile (IJ). The IJ is a free‐living stage of the nematode that seeks out and infects insect larvae. Once inside the insect the IJ release Photorhabdus into the haemolymph where the bacteria rapidly proliferate, killing the insect within 48–72 h. The nematodes grow and reproduce in the insect cadaver by feeding on the Photorhabdus biomass. In this study we use Photorhabdus temperata K122 to show that genes involved in iron acquisition play a key role during the course of the tripartite bacteria–nematode–insect interaction. We show that a strain carrying a mutation in a gene with homology to exbD, encoding a component of the TonB complex, is unable to grow well in conditions where iron is not freely available. In addition, this mutant, BMM417, requires a longer time to kill the insect larvae than the wild‐type bacteria and this defect in pathogenicity is complemented by the co‐injection of iron. Moreover, the increase in LT50 observed with BMM417 is correlated with a significantly slower in vivo growth rate suggesting that iron is limiting in the insect. We also show that BMM417 is unable to support the growth and development of the Heterorhabditis nematode. Addition of exogenous iron to the growth media restores nematode growth and development on BMM417, suggesting that aspects of iron metaboism in Photorhabdus are important during the symbiosis with the nematode.
The Mep2p ammonium permease controls nitrogen starvation‐induced filamentous growth in Candida albicans
Authors: Biswas Kajal , Morschhäuser Joachim 
Published: April 2005

SummaryNitrogen starvation is one of the signals that induce Candida albicans, the major fungal pathogen of humans, to switch from yeast to filamentous growth. In response to nitrogen starvation, C. albicans expresses the MEP1 and MEP2 genes, which encode two ammonium permeases that enable growth when limiting concentrations of ammonium are the only available nitrogen source. In addition to its role as an ammonium transporter, Mep2p, but not Mep1p, also has a central function in the induction of filamentous growth on a solid surface under limiting nitrogen conditions. When ammonium is absent or present at low concentrations, Mep2p activates both the Cph1p‐dependent mitogen‐activated protein (MAP) kinase pathway and the cAMP‐dependent signalling pathway in a Ras1p‐dependent fashion via its C‐terminal cytoplasmic tail, which is essential for signalling but dispensable for ammonium transport. In contrast, under ammonium‐replete conditions that require transporter‐mediated uptake Mep2p is engaged in ammonium transport and signalling is blocked such that C. albicans continues to grow in the budding yeast form. Mep2p is a less efficient ammonium transporter than Mep1p and is expressed at much higher levels, a distinguishing feature that is important for its signalling function. At sufficiently high concentrations, ammonium represses filamentous growth even when the signalling pathways are artificially activated. Therefore, C. albicans has established a regulatory circuit in which a preferred nitrogen source, ammonium, also serves as an inhibitor of morphogenesis that is taken up into the cell by the same transporter that mediates the induction of filamentous growth in response to nitrogen starvation.
Different proteins bind to the butyrolactone receptor protein ARE sequence located upstream of the regulatory ccaR gene of Streptomyces clavuligerus
Authors: Santamarta Irene , Pérez‐Redondo Rosario , Lorenzana Luis M. , Martín Juan F. , Liras Paloma 
Published: April 2005

SummaryCell‐free extracts from Streptomyces clavuligerus, purified by elution from heparin‐agarose with an ARE‐containing DNA fragment or by salt elution chromatography, bind to a 26 nt ARE sequence, for butyrolactone receptor proteins (AREccaR). This sequence, located upstream of the ccaR gene, encodes the activator protein CcaR required for clavulanic acid and cephamycin C biosynthesis. The binding is specific for the ARE sequence as shown by competition with a 34 nt unlabelled probe identical to the ARE sequence. A brp gene, encoding a butyrolactone receptor protein, was cloned from S. clavuligerus. Sixty‐one nucleotides upstream of brp another ARE sequence (AREbrp) was found, suggesting that Brp autoregulates its expression. Pure recombinant rBrp protein binds specifically to the ARE sequences present upstream of ccaR and brp. A brp‐deleted mutant, S. clavuligerus Δbrp::neo1, produced 150–300% clavulanic acid and 120–220% cephamycin C as compared with the parental strain, suggesting that Brp exerts a repressor role in antibiotic biosynthesis. EMSA assays using affinity chromatography extracts from the deletion mutant S. clavuligerus Δbrp::neo1 lacked a high‐mobility band‐shift due to Brp but still showed the slow‐mobility band‐shift observed in the wild‐type strain. These results indicate that two different proteins bind specifically to the ARE sequence and modulate clavulanic acid and cephamycin biosynthesis by its action on ccaR gene expression.
Mutational analysis of the group A streptococcal operon encoding streptolysin S and its virulence role in invasive infection
Authors: Datta Vivekanand , Myskowski Sandra M. , Kwinn Laura A. , Chiem Daniel N. , Varki Nissi , Kansal Rita G. , Kotb Malak , Nizet Victor 
Published: April 2005

SummaryThe pathogen group A Streptococcus (GAS) produces a wide spectrum of infections including necrotizing fasciitis (NF). Streptolysin S (SLS) produces the hallmark β‐haemolytic phenotype produced by GAS. The nine‐gene GAS locus (sagA–sagI) resembling a bacteriocin biosynthetic operon is necessary and sufficient  for  SLS  production.  Using  precise,  in‐frame allelic exchange mutagenesis and single‐gene complementation, we show sagA, sagB, sagC, sagD, sagE, sagF and sagG are each individually required for SLS production, and that sagE may further serve an immunity function. Limited site‐directed mutagenesis of specific amino acids in the SagA prepropeptide supports the designation of SLS as a bacteriocin‐like toxin. No significant pleotrophic effects of sagA deletion were observed on M protein, capsule or cysteine protease production. In a murine model of NF, the SLS‐negative M1T1 GAS mutant was markedly diminished in its ability to produce necrotic skin ulcers and spread to the systemic circulation. The SLS toxin impaired phagocytic clearance and promoted epithelial cell cytotoxicity, the latter phenotype being enhanced by the effects of M protein and streptolysin O. We conclude that all genetic components of the sag operon are required for expression of functional SLS, an important virulence factor in the pathogenesis of invasive M1T1 GAS infection.
Differential gene expression in genetically identical sister cells: the initiation of sporulation in Bacillus subtilis†
Authors: Yudkin Michael D. , Clarkson Joanna 
Published: April 2005

SummaryEarly in sporulation, the cell divides asymmetrically to give two sister compartments, a smaller prespore and a larger mother cell. Differential gene expression in these compartments depends on the regulation of the first sporulation‐specific sigma factor, σF, which is activated only in the prespore. Regulation relies on the interactions of four proteins –σF, its antisigma SpoIIAB (which also has protein kinase activity), the anti‐antisigma SpoIIAA and the protein phosphatase SpoIIE. Before asymmetric division, and in the mother cell after division, σF is held in an inactive complex with SpoIIAB and ATP; SpoIIAA is in its phosphorylated form. To disrupt the complex so as to liberate σF in the prespore, dephosphorylated SpoIIAA is needed, and this is made available by SpoIIE. Thereafter, SpoIIAB and SpoIIE are active simultaneously in the prespore, cycling SpoIIAA through phosphorylated and non‐phosphorylated forms. This cycle detains SpoIIAB in a state in which it cannot inhibit σF. Results from biophysical techniques, mathematical simulations and enzyme kinetics have now helped to elucidate the dynamics of the protein–protein interactions involved. An understanding of these dynamics largely accounts for the regulation of σF. We show that the system is tuned to be highly efficient in its use of components and extremely economical in conserving ATP.
Scrotal dartos flap for the prevention of the urethrocutaneous fistula on hypospadias urethroplasty
Authors: HAYASHI YUTARO , KOJIMA YOSHIYUKI , KUROKAWA SATOSHI , MIZUNO KENTARO , NAKANE AKIHIRO , KOHRI KENJIRO 
Published: April 2005

Abstract  Background:  Urethrocutaneous fistula is a common complication of urethroplasty for severe hypospadias, even when a microsurgical technique is applied.Patients and methods:  From June 2001 to July 2003, we applied the scrotal dartos flap wrapping technique to prevent the occurrence of urethrocutaneous fistula in 14 patients with hypospadias.Results:  Hypospadias was repaired without fistula formation in all but one patient, who developed a tiny fistula which was later closed successfully by a simple procedure.Conclusions:  We recommend the scrotal dartos wrapping technique for covering the neourethra with a well‐vascularized flap because of fewer complications, although the procedure to obtain the vascularized flap may take longer.
Penile erectile responses to electric stimulation are enhanced by a new phosphodiesterase type‐5 inhibitor
Authors: YU JAE YOUNG , KANG KYUNG KOO , YOO MOOHI , KWON JONG WON 
Published: April 2005

Abstract  Aim:  This study was conducted to investigate the effect of DA‐8159, a new phosphodiesterase type‐5 (PDE5) inhibitor, on electrostimulation‐induced penile erection in rats.Methods:  Intracavernous pressure (ICP) and arterial blood pressure (BP) were simultaneously recorded through electric pelvic‐ganglion stimulation (2–10 Hz) after the oral administration of DA‐8159 (3 or 10 mg/kg) in normal and streptozotocin‐induced diabetic rats. Statistical analysis was performed on the maximal intracavernous pressure (ICP), detumescence time, maximal intracavernous pressure/blood pressure (ICP/BP) ratio, and the area under the curve (AUC) of the ICP/BP ratio.Results:  In normal and diabetic rats, electrical stimulation of the pelvic ganglion induced a frequency‐ and dose‐dependent increase in the intracavernous pressure. The ICP/BP ratio and the corresponding AUC values were also significantly and dose‐dependently increased after DA‐8159 administration. In addition, the detumescence time significantly increased after DA‐8159 administration compared to that of the controls.Conclusions:  These results show that the DA‐8159 significantly increased the intracavernous pressure response and prolonged the decay period induced by electrical stimulation of the pelvic ganglion, and suggest that DA‐8159 might be a potential therapeutic agent for the treatment of erectile dysfunction.
Prediction of potentially insignificant prostate cancer in men undergoing radical prostatectomy for clinically organ‐confined disease
Authors: MIYAKE HIDEAKI , SAKAI IORI , HARADA KEN‐ICHI , HARA ISAO , ETO HIROSHI 
Published: April 2005

Abstract  Background:  The objectives of the present study were to characterize, according to tumor significance, the clinicopathological features of patients with prostate cancer who underwent radical prostatectomy, and to determine useful parameters for predicting insignificant disease before surgery.Methods:  In this series, we included 195 patients who underwent radical prostatectomy for clinically organ‐confined prostate cancer at our institution between January 1999 and November 2003. Several clinicopathological factors were analyzed, focusing on whether the largest tumor volume in radical prostatectomy specimens was ≥0.5 cm3 or <0.5 cm3, which is the criterion defined to distinguish insignificant cancer from significant cancer.Results:  Potentially insignificant cancer was detected in 28 of 195 patients (14.4%). There were significant differences between patients with insignificant disease and those with significant disease in serum prostate specific antigen (PSA) as well as all biopsy parameters, with the exception of biopsy Gleason score. Furthermore, final pathological examination demonstrated that these two patient groups showed significant differences in Gleason score and the incidence of extraprostatic disease extension. Pearson's correlation analysis showed that tumor volume in the prostatectomy specimens was significantly associated with serum PSA and all biopsy parameters; however, each of the correlations was comparatively weak. There was no single parameter that could viewed as a useful predictor of tumor significance. The best model for predicting insignificant tumor was the combined use of biopsy Gleason score <7 and percent of positive biopsy core (PPBC) <15%; however, the further addition of serum PSA <10 ng/mL to these two parameters failed to enhance the predictive value of cancer significance.Conclusions:  These findings indicate that clinicopathological findings suggesting favorable features are well observed in patients with potentially insignificant prostate cancer compared to those with significant prostate cancer, and the combination of a biopsy Gleason score <7 and PPBC <15% might be useful as a predictor of insignificant disease.
Relationship between corneal thickness and optic disc damage in glaucoma
Authors: Hewitt Alex W , Cooper Richard L 
Published: April 2005

Abstract Background: Central corneal thickness (CCT) has been found to be a powerful predictor for the development of glaucoma in patients with ocular hypertension. This study aimed to determine whether CCT was also related to glaucoma severity. Methods: The vertical cup/disc ratio (VCDR) was used as a single objective measure of glaucoma severity. Vertical cup diameters and vertical disc diameters were measured using a graticule attached to a 60 D Volk lens, in consecutive patients presenting to a single ophthalmologist. Measurements were corrected for magnification. The difference between corrected VCDR and 95% probability of VCDR normality was compared to CCT, which was measured with an ultrasonic pachymeter. Results: During the study period 554 eyes from 281 patients with glaucoma were reviewed. The mean CCT was 519.0 µm, with the mean corrected VCDR being 0.71. A univariate linear regression model revealed that an increase of 10 µm in CCT resulted in a 0.009 decrease in the difference between true VCDR and the predicted normal VCDR. The R2 value for the regression was 0.04 (P < 0.0001). Conclusion: There is a highly statistically significant, albeit small, negative correlation between corneal thickness and glaucoma severity. This study supports the notion that CCT should be measured in the assessment of patients with glaucoma. Progressive thinning or presence of a thin cornea may have pathogenic or prognostic roles in some types of glaucoma.
Local or short‐term systemic costimulatory molecule blockade prolongs rat corneal allograft survival
Authors: Thiel Michael A , Steiger Jurg U , O'Connell Philip J , Lehnert Anne M , Coster Douglas J , Williams Keryn A 
Published: April 2005

Abstract Background: Costimulatory molecule blockade with antibody‐based immunosuppressive agents has been shown to prolong the survival of many types of allograft. The effects were evaluated of local costimulatory molecule blockade with different CTLA4‐Ig constructs and of systemic, short‐term treatment with an anti‐CD28 monoclonal antibody on orthotopic corneal allograft survival in the rat. Methods: Adult Fischer‐344 rats underwent Wistar‐Furth orthotopic corneal grafts. The rats were treated with two different CTLA4‐fusion proteins administered intraocularly in the perioperative period, or systemically with anti‐CD28 monoclonal antibody JJ319. Corneal graft survival was determined by daily slit‐lamp examination. The day of rejection was defined as the first postoperative day on which the iris margin was no longer clearly visible through the corneal graft. Results: Local administration of CTLA4‐fusion protein with mutated immunoglobulin constant region domains via a single perioperative intraocular injection prolonged corneal graft survival modestly but significantly (P < 0.05), in contrast to a CTLA4‐fusion protein with wild‐type immunoglobulin domains, which had no effect on graft survival (P > 0.5). Systemic short‐term administration of 400 µg total of an anti‐CD28 monoclonal antibody also prolonged corneal graft survival significantly (P < 0.05) and was more effective than systemic administration of 2 mg total of CTLA4‐fusion protein (P < 0.05). Conclusions: Local administration of CTLA4‐fusion protein with mutated (non‐functional) immunoglobulin domains or systemic administration of anti‐CD28 monoclonal antibody can prolong corneal allograft survival in the rat.
Novel ophthalmological features in hereditary endotheliopathy with retinopathy, nephropathy and stroke syndrome
Authors: Cohn Amy C , Kotschet Katya , Veitch Alistair , Delatycki Martin B , McCombe Mark F 
Published: April 2005

AbstractThe ophthalmic features are reported of a member of an Australian pedigree with three affected individuals spanning two generations with a hereditary endotheliopathy syndrome resulting in retinopathy, leukoencephalopathy and nephropathy. The index case initially presented with asymptomatic retinopathy, cerebral microvascular disease, nephropathy and raised inflammatory markers. The clinical, neuro‐radiological, biochemical and histopathological findings in this patient are consistent with a diagnosis of hereditary endotheliopathy, retinopathy, nephropathy and stroke (HERNS). Linkage analysis has identified a locus for HERNS on chromosome 3p21.1‐p21.3. This locus is shared with two other diseases: hereditary vascular retinopathy (HVR) and cerebroretinal vasculopathy (CRV). Although peripheral retinal involvement is a feature of HVR, it has not previously been described in HERNS. This case represents a novel phenotype of HERNS, and serves to blur the distinction between the vasculopathies mapping to chromosome 3p21. Although previously thought to be distinct clinical entities, it is possible that HERNS, HVR and CRV simply represent different phenotypes of the same disease. This will only be clarified with the identification of the gene or genes. This case also raises the question of how best to manage rare forms of vascular retinopathy.
Couching for cataract and Sino‐Indian medical exchange from the sixth to the twelfth century ad
Authors: Fan Ka Wai 
Published: April 2005

AbstractThis paper investigates the processes of interpretation and integration of the Indian ophthalmic technique known as ‘couching for cataract’ into Chinese medicine from the sixth to the twelfth century ad. The Indian medical knowledge of this procedure was eventually accepted because it could be reconstructed following Chinese medical concepts.
Clinical manifestations of a unique X‐linked retinal disorder in a large New Zealand family with a novel mutation in CACNA1F, the gene responsible for CSNB2
Authors: Hope Carolyn I , Sharp Dianne M , Hemara‐Wahanui Ariana , Sissingh Jennifer I , Lundon Patricia , Mitchell Ed A , Maw Marion A , Clover Gillian M 
Published: April 2005

Abstract Purpose: To describe the phenotype in a New Zealand family with an unusual severe X‐linked retinal disorder with a novel I745T mutation in CACNA1F, the gene responsible for incomplete congenital stationary night blindness (CSNB2). Methods: Members of the family tree were invited for clinical, psychophysical and electrodiagnostic evaluation. Results: Male family members had severe non‐progressive visual impairment, abnormal colour vision, congenital nystagmus, hyperopia and normal fundi. Some were intellectually disabled. Female family members had congenital nystagmus and decreased visual acuity frequently associated with high myopia. Electroretinograms (ERG) identified reduced rod and cone responses with negative waveform in male and female family members, with atypical features for CSNB2. Conclusions: Although there were similarities to CSNB2, distinctive features in male family members included severity of phenotype, and association of intellectual disability. Moreover, all female heterozygotes had clinical and ERG abnormalities. CACNA1F encodes the Cav1.4 α1 subunit of a voltage‐gated calcium channel, which may mediate neurotransmitter release from photoreceptors. Molecular analyses, reported separately, identified a novel I745T CACNA1F mutation that was associated in vitro with major alterations in gating and kinetics of the Cav1.4 channel. It is speculated that the unique phenotype described in this family may reflect similarly altered function of Cav1.4 channel activity in vivo.
Effect of mitomycin C on ciliary body and intraocular pressure with various application depths: an experimental study
Authors: Sari Ayca , Onol Merih , Ozdek Sengül , Ozogul Candan , Hasanreisoglu Berati 
Published: April 2005

Abstract Background: To evaluate the effects of mitomycin C (MMC) on intraocular pressure (IOP) and ciliary body via transmission electron microscopy when applied under conjunctiva or different depths of sclera, without performing any filtering surgery. Methods: Thirty‐six eyes of 36 New Zealand albino rabbits were used in this study. MMC was prepared in a concentration of 0.4 mg/mL and 0.05 cc (20 µg) was soaked in preprepared sterile surgical sponges. Six groups each consisting of six eyes were formed and IOP was measured preoperatively. Group 1 was the control group: the superior conjunctiva was opened and only irrigated with balanced salt solution (BSS). In group 2, MMC soaked sponges were applied under the conjunctiva. In groups 3 and 4, a scleral flap of approximately 1/3 scleral thickness was prepared and in groups 5 and 6, and a scleral flap of approximately 2/3 scleral thickness was prepared, all with a standard size of 4 × 4 mm. MMC soaked sponges were applied under these areas for 5 min in eyes in groups 3 and 5 followed by an irrigation of the relevant areas with 10 cc BSS, whereas only irrigation with BSS was done in groups 4 and 6 as control groups. No filtering procedure was performed in any of the eyes. Eyes were enucleated on the 30th day following measurement of IOP and the ciliary body regions were evaluated using transmission electron microscopy. Kruskal–Wallis test was used for the statistical assessment of IOP between groups. Results: The deep scleral flap group (group 5) showed statistically significantly more IOP reduction than both the superficial scleral flap group (group 3; P = 0.004) and the subconjunctival group (group 2; P = 0.002) on postoperative day 30. Electron microscopic evaluation of the surgical groups revealed a wide range of different histopathological effects due to different MMC application methods. The histopathological changes were more evident in the group 5, where MMC was applied under deep scleral flap. Conclusions: Subscleral application of MMC seems to provide greater IOP decrease than subconjunctival application, possibly caused by a more significant ciliary body toxicity. This may be the beginning of a non‐penetrating, easy to perform and safe method to decrease IOP in glaucoma patients, which the authors call ‘toxic ciliary ablation surgery’. However, the long‐term results and complications must be assessed with further studies.