bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intermittent Footshock Facilitates Dendritic Vasopressin Release but Suppresses Vasopressin Synthesis within the Rat Supraoptic Nucleus
Authors: Onaka T. , Serino R. , Ueta Y. 
Published: May 2003

AbstractEmotional stress inhibits vasopressin release from the pituitary but may facilitate its release from the dendrites in the hypothalamus. We examined effects of intermittently applied footshock upon the amount of vasopressin heteronuclear RNA in the hypothalamus. The footshock decreased plasma vasopressin concentration but increased its extracellular concentration within the supraoptic nucleus. The contents of the vasopressin heteronuclear RNA in the supraoptic nucleus were significantly decreased after the shock. These data suggest that intermittent footshock decreases not only vasopressin release from the axon terminals in the pituitary, but also vasopressin synthesis in the cell bodies in the hypothalamus while the stimulus facilitates vasopressin release from the dendrites in the hypothalamus. The data also suggest differential control of dendritic vasopressin release and synthesis in the hypothalamus.
Ten families of variant genes encoded in subtelomeric regions of multiple chromosomes of Plasmodium chabaudi, a malaria species that undergoes antigenic variation in the laboratory mouse
Authors: Fischer Katja , Chavchich Marina , Huestis Robert , Wilson Danny W. , Kemp David J. , Saul Allan 
Published: May 2003

SummaryThe chromosome ends of human malaria parasites harbour many genes encoding proteins that are exported to the surface of infected red cells, often being involved in host–parasite interactions and immune evasion. Unlike other murine malaria parasites Plasmodium chabaudi undergoes antigenic variation during passage in the laboratory mouse and hence is a model suitable for investigation of switching mechanisms. However, little is known about the subtelomeric regions of P. chabaudi chromosomes and its variable antigens. Here we report 80 kb of sequence from an end of one P. chabaudi chromosome. Hybridization of probes spanning this region to two dimensional pulsed field gels of the genome revealed 10 multicopy gene families located exclusively in subtelomeric regions of multiple P. chabaudi chromosomes, interspersed amongst multicopy intergenic regions. Hence all chromosomes share a common subtelomeric structure, presumably playing a similar role in spatial positioning as the P. falciparum Rep20 sequence. Expression in blood stages, domains characteristic of surface antigens and copy numbers between four and several hundred per genome, indicate a functional role in antigenic variation for some of these families. We identify members of the cir family, as well as novel genes, that although clearly homologous to cir have large low complexity regions in the predicted extracellular domains. Although all families have homologues in other rodent Plasmodium species, four were previously not known to be subtelomeric. Six have homologues in human and simian malarias.
Opposing selective forces for expression of the gonococcal lactoferrin receptor
Authors: Anderson James E. , Hobbs Marcia M. , Biswas Gour D. , Sparling P. Frederick 
Published: May 2003

SummaryAll isolates of Neisseria gonorrhoeae express receptors that bind human transferrin (Tf). Although lactoferrin (Lf) is abundant on mucosa and in purulent exudates, many gonococci do not express an Lf receptor. The naturally occurring Lf receptor deletion mutant FA1090 (LbpB–LbpA–) is infectious, but a Tf receptor mutant of FA1090 is unable to infect male volunteers [Cornelissen, C.N., Kelley, M., Hobbs, M.M., Anderson, J.E., Cannon, J.G., Cohen, M.S., and Sparling, P.F. (1998) Mol Microbiol 27: 611–616]. Here, we report that expression of an Lf receptor in the absence of the Tf receptor was sufficient for infection, and that expression of both Lf and Tf receptors resulted in a competitive advantage over a strain that made only the Tf receptor in mixed infection of male volunteers. We confirmed that nearly 50% of clinical isolates do not make an Lf receptor. Surprisingly, about half of geographically diverse Lf – isolates representing many different auxotypes and porin serovars carried an identical lbpB lbpA deletion. Among Lf+ strains, all produced the integral outer membrane protein LbpA, but 70% did not express the lipoprotein LbpB. Thus, there are apparently selective pressures for expression of the Lf receptor in the male urethra that are balanced by others against expression of the Lf receptor in niches other than the male urethra.
A well‐conserved Plasmodium falciparum var gene shows an unusual stage‐specific transcript pattern
Authors: Kyes Sue A. , Christodoulou Zoe , Raza Ahmed , Horrocks Paul , Pinches Robert , Rowe J. Alexandra , Newbold Chris I. 
Published: May 2003

SummaryThe var multicopy gene family encodes Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variant antigens, which, through their ability to adhere to a variety of host receptors, are thought to be important virulence factors. The predominant expression of a single cytoadherent PfEMP1 type on an infected red blood cell, and the switching between different PfEMP1 types to evade host protective antibody responses, are processes thought to be controlled at the transcriptional level. Contradictory data have been published on the timing of var gene transcription. Reverse transcription‐polymerase chain reaction (RT‐PCR) data suggested that transcription of the predominant var gene occurs in the later (pigmented trophozoite) stages, whereas Northern blot data indicated such transcripts only in early (ring) stages. We investigated this discrepancy by Northern blot, with probes covering a diverse var gene repertoire. We confirm that almost all var transcript types were detected only in ring stages. However, one type, the well‐conserved varCSA transcript, was present constitutively in different laboratory parasites and does not appear to undergo antigenic variation. Although varCSA has been shown to encode a chondroitin sulphate A (CSA)‐binding PfEMP1, we find that the presence of full‐length varCSA transcripts does not correlate with the CSA‐binding phenotype.
Oligomerization and activation of the FliI ATPase central to bacterial flagellum assembly
Authors: Claret Laurent , Calder Susannah R. , Higgins Matthew , Hughes Colin 
Published: May 2003

SummaryFliI is the peripheral membrane ATPase pivotal to the type III protein export mechanism underlying the assembly of the bacterial flagellum. Gel filtration and multiangle light scattering showed that purified soluble native FliI protein was in a monomeric state but, in the presence of ATP, FliI showed a propensity to oligomerize. Electron microscopy revealed that FliI assembles to a ring structure, the yield of which was increased by the presence of a non‐hydrolysable ATP analogue. Single particle analysis of the resulting electron micrograph images, to which no symmetry was applied, showed that the FliI ring structure has sixfold symmetry and an external diameter of ≈ 10 nm. The oligomeric ring has a central cavity of 2.5–3.0 nm, which is comparable to the known diameter of the flagellar export channel into which export substrates feed. Enzymatic activity of the FliI ATPase showed positive co‐operativity, establishing that oligomerization and enzyme activity are coupled. Escherichia coli phospholipids increased enzyme co‐operativity, and in vitro cross‐linking demonstrated that they promoted FliI multimerization. The data reveal central facets of the structure and action of the flagellar assembly ATPase and, by extension, the homologous ATPases of virulence‐related type III export systems.
The twin‐arginine translocation (Tat) system is essential for Rhizobium–legume symbiosis
Authors: Meloni Stefania , Rey Luis , Sidler Stephan , Imperial Juan , Ruiz‐Argüeso Tomás , Palacios José M. 
Published: May 2003

SummaryThe Tat (twin‐arginine translocation) system mediates export of periplasmic proteins in folded conformation. Proteins transported via Tat contain a characteristic twin‐arginine motif in their signal peptide. Genetic determinants (tatABC genes) of the Tat system from Rhizobium leguminosarum bv. viciae were cloned and characterized, and a tatBC deletion mutant was constructed. The mutant lacked the ability for membrane targeting of hydrogenase, a known Tat substrate, and was impaired in hydrogenase activity. Interestingly, in the absence of a functional Tat system, only small, white nodules unable to fix nitrogen were induced in symbiosis with pea plants. Analysis of nodule structure and location of green fluorescent protein (GFP)‐tagged bacteria within nodules indicated that the symbiotic process was blocked in the tat mutant at a stage previous to bacteria release into cortical cells. The R. leguminosarum Tat‐deficient mutant lacked a functional cytochrome bc1 complex. This was consistent with the fact that R. leguminosarum Rieske protein, a key component of the symbiosis‐essential cytochrome bc1 complex, contained a typical twin‐arginine signal peptide. However, comparative analyses of nodule structure indicated that nodule development in the tat mutant was arrested at an earlier step than in a cytochrome bc1 mutant. These data indicate that the Tat pathway is also critical for proteins relevant to the initial stages of the symbiotic process.
The Escherichia coli amidase AmiC is a periplasmic septal ring component exported via the twin‐arginine transport pathway
Authors: Bernhardt Thomas G. , De Boer Piet A. J. 
Published: May 2003

SummaryThe N‐acetylmuramoyl‐l‐alanine amidases of Escherichia coli (AmiA, B and C) are periplasmic enzymes that remove murein cross‐links by cleaving the peptide moiety from N‐acetylmuramic acid. Ami– cells form chains, indicating that the amidases help to split the septal murein. Interestingly, cells defective in the twin‐arginine protein transport (Tat) pathway show a similar division defect. We find that both AmiA and AmiC are routed to the periplasm via Tat, providing an explanation for the Tat– division phenotype. Taking advantage of the ability of Tat to export prefolded (fluorescent) green fluorescent protein (GFP) to the periplasm, we sublocalized AmiA and AmiC in live cells using functional fusions to GFP. Interestingly, the periplasmic localization of the fusions differed markedly. AmiA–GFP appeared to be dispersed throughout the periplasm in all cells. AmiC–GFP similarly appeared throughout the periplasm in small cells, but was concentrated almost exclusively at the septal ring in constricting cells. Recruitment of AmiC to the ring was mediated by an N‐terminal non‐amidase targeting domain and required the septal ring component FtsN. AmiC therefore replaces FtsN as the latest known recruit to the septal ring and is the first entirely periplasmic component to be localized.
Three‐way interactions among the Sfh, StpA and H‐NS nucleoid‐structuring proteins of Shigella flexneri 2a strain 2457T
Authors: Deighan Padraig , Beloin Christophe , Dorman Charles J. 
Published: May 2003

Summary Shigella flexneri 2a strain 2457T has been found to express Sfh, a new member of the H‐NS‐like family of nucleoid‐structuring proteins. With H‐NS and its paralogue, StpA, this brings to three the number of these proteins expressed in this bacterium. This raises the possibility that three‐way interactions may occur in S. flexneri among these proteins and between the proteins and each other's genes. Such three‐way interactions among H‐NS‐like proteins have not been described previously. The expression of the sfh, stpA and hns genes was studied at the transcriptional and post‐transcriptional levels. The Sfh protein displays growth phase‐dependent regulation that distinguishes it from both H‐NS and StpA. Like H‐NS and StpA, Sfh can bind to its own promoter region, it negatively autoregulates transcription of its own gene, and when overexpressed all three proteins cross‐repress transcription of each other's genes. The presence of highly conserved oligomerization domains within these molecules suggested the possibility of protein–protein interactions. Like H‐NS and StpA, the purified Sfh protein forms homodimers in solution. Using the yeast two‐hybrid assay we show that each of the three proteins also forms homodimers in vivo and, additionally, each protein can form heterodimers with either of its homologues. This raises the possibility that Sfh may modulate the activities of H‐NS and StpA, and vice versa.
Study of the Pathological Effect of Escherichia coli Endotoxin in Rams
Authors: Sokkar S. M. , Darwiesh G. , Madbooly A. , Kaaden O.‐R. 
Published: May 2003

SummaryThis experimental study was carried out on nine adult rams. Rams were injected intravenously with Escherichia coli endotoxin serotype 055:B5. The regimen of injections is described fully. Blood and semen samples were collected periodically to evaluate the changes in blood and semen picture. The reproductive as well as the visceral organs were collected and examined macroscopically and microscopically. The results of the study revealed that sperm cell abnormalities and serum testosterone level were increased, and sperm acrosomal abnormalities were significantly increased. The total leucocytic count was significantly decreased. The histopathological examination revealed severe testicular degeneration in addition to various other lesions in the visceral organs. Scanning electron microscope of the sperm cells revealed detached acrosomes, knobbed acrosomes and coiled tails.
Tolerance of barley seed germination to cold‐ and drought‐stress expressed as seed vigour
Authors: Chloupek O. , HrstkovÁ P. , Jurecka D. , Graner A. 
Published: June 2003

AbstractIn barley, high seed vigour is a precondition for rapid and homogenous field emergence and good malting quality. Seed vigour was defined as germination percentage under stress conditions (10°C, drought stress ‐ 2 Bars) in 7‐8 barley varieties grown in 7‐8 locations in the Czech Republic over 7 years. Three of the 7 years were not suitable for high seed quality, probably because of unsuitable weather, as average seed vigour reached only 61, 77 and 86%, respectively. In the remaining 4 years, the average vigour exceeded 94%. The impact of variety on seed vigour was higher in the ‘bad years’ and the impact of location was higher in the other years. Varieties with higher vigour from all locations in the ‘bad years’ were identified. Lower vigour was related to the high occurrence of fungi (indicated by ergosterol assays) and to lower field emergence rates of seed samples. The results support the possibility of selecting for improvement of barley seed vigour, which is related to tolerance to various conditions during emergence and to homogenous malting.
Fusarium head blight‐resistant wheat line ‘Bizel’ does not contain rye chromatin
Authors: Bourdoncle W. , Ohm H. W. , Weber W. E. 
Published: June 2003

AbstractFusarium head blight (FHB), primarily caused by Fusarium graminearum in North America can result in significant losses in the yield and quality of wheat (Triticum aestivum L). Resistance sources have been largely limited to Chinese germplasm and, in particular, Sumai 3 or its derivatives. In recent years, resistance has been identified in Europe. Previous studies using the wheat line ‘Bizel’, developed in France, have shown that it has resistance to Fusarium head blight. Pedigree information shows that one of its progenitors is rye. This experiment was conducted to determine if ‘Bizel’ has rye chromatin, with the goal of developing a strategy for mapping FHB resistance genes. Two methods based on repetitive DNA sequences specific to rye were implemented. With both approaches, it was demonstrated that ‘Bizel’ does not contain rye chromatin. Consequently, wheat SSRs can be used to map ‘Bizel’ resistance genes for FHB.
Interspecific hybridization of a multiploid mutant of durum wheat with rye and Triticum monococcum L. results in pentaploid hybrids
Authors: Klindworth D. L. , Williams N. D. , McIntosh R. A. 
Published: June 2003

AbstractThe multiploid mutant of durum wheat is a genotype that produces unreduced gametes. Our objective was to test the recovery of pentaploid hybrids in crosses of the mutant with rye and Triticum monococcum L. Compared with check crosses, the mutant had a two‐third reduction in percent seed set for rye crosses, but had only a slight decrease in crossability with T. monococcum. Pentaploid hybrids were associated with plump seeds of the mutant/rye cross, and with shrivelled seeds of the mutant/T. monococcum cross. We suggest that the endosperm balance number hypothesis explains the association of pentaploid hybrids with endosperm type. This association made for easy recovery of pentaploid hybrids from crosses to both species. Mature, plump seeds from the mutant/rye cross were germinated and pentaploid hybrids were recovered. One pentaploid hybrid was recovered for every 50.5 and 15.1 florets pollinated with rye and T. monococcum, respectively. Unreduced gametes in the multiploid mutant will facilitate interspecific hybridization by reducing the time to produce pentaploid plants.
Acute urethritis caused by Neisseria meningitidis
Authors: KANEMITSU NORIYUKI , HAYASHI ISSEI , SATOH NODOKA , HAYAKAWA TAKAHIRO , MITSUYA HIDEO , HAYASE YOSIMASA , HIRAMOTO KEN , KOJIMA MUNEKADO 
Published: May 2003

AbstractA 48‐year‐old heterosexual Japanese man visited the outpatient clinic of Nagoya Urology Hospital, complaining of burning pain at voiding and pus discharge from the urethral orifice. These symptoms appeared the day following oral‐genital contact (fellatio) with a commercial sex worker. On the basis of the presumptive clinical diagnosis of gonorrhea because of the microscopic detection of diplococci in the urethral discharge, he was treated with levofloxacin (300 mg per day) for 7 days. His symptoms responded quickly and urinalysis taken 7 days later was normal. Microbiological examinations isolated Neisseria meningitidis in the urethral discharge by culture with the use of enzymatic profiles. Further prevalence of sexually transmitted diseases (STD) through oral‐genital contact would lead to an increase in meningococcal urethritis.
Transition zone biopsy and prediction of extraprostatic extension at radical prostatectomy
Authors: ÖNDER ALI ULVI , YAYCIOGLU OZGUR , ATAUS SULEYMAN , GUL UMIT , DEMIRKESEN OKTAY , YALCIN VELI , SOLOK VURAL 
Published: May 2003

AbstractBackground: There is limited data in the literature that suggests that transition zone (TZ) biopsy might be useful for the prediction of extraprostatic extension (EPE) in clinically localized prostate cancer. We studied the role of TZ biopsy in the prediction of EPE.Methods: Transition zone biopsies were performed in addition to systematic peripheral zone (PZ) biopsies between November 1995 and December 1999. During this period, 59 patients underwent radical prostatectomy for clinically localized disease. Final pathological results were compared with preoperative clinical and biopsy findings.Results: Of the 59 patients who underwent radical prostatectomy, 46 had cancer only in the PZ cores and 13 had cancer both in the PZ and the TZ cores at the biopsy. Final histopathological results revealed EPE in 19 (32%) patients and positive surgical margins in 22 (37%). In univariate analysis of age, prostate‐specific antigen (PSA), mean percentage of positive PZ cores, mean biopsy Gleason score and positive TZ biopsy, there was a significant difference for serum PSA levels (P = 0.021), presence of positive TZ cores (P = 0.018) and percentage of positive PZ cores in patients with and without EPE (P < 0.001). In multivariate analysis, the single independent predictor of EPE was the percentage of positive PZ biopsy cores (P = 0.0227). There was agreement between the side of positive TZ biopsy and EPE in seven of eight patients.Conclusion: Taking two TZ cores in addition to peripheral sextant biopsy did not result in better prediction of EPE. The relationship between TZ involvement and the presence of EPE can be investigated further in radical prostatectomy specimens.
Japan's share of research output in urology and nephrology
Authors: RAHMAN MAHBUBUR , SAKAMOTO JUNICHI , FUKUI TSUGUYA 
Published: May 2003

AbstractBackground: Recent studies have documented Japan's share of articles in different biomedical fields. However, Japan's contribution to urology and nephrology is not known.Methods: Seven journals in this field with the highest impact factors were selected to obtain relevant data. In June 2002, we searched the Medline database to obtain country affiliation details of articles published in the selected journals during 1991–2000. The proportion of articles with a higher grade of evidence (randomized controlled trials or clinical trials, cohort studies and case‐control studies) were also generated and compared to the average values for all articles published in these journals.Results: Of the total number of articles (22 232), Japan's share of research output for the selected journals in urology and nephrology was 6% (1335 articles) and it ranked second in the world following the USA (56.5%). The recent increase in the share was statistically significant for Japan, Austria, France, Germany, Spain and Turkey. The proportion of articles with a high grade of evidence was lower for articles originated in Japan than for the total number of articles.Conclusion: Japan's contribution to urology and nephrology research is within the range of its contribution to other biomedical fields. However, the number of high quality clinical research conducted in Japan in this field was small.
Experience with flexible video cystoscope equipped with built‐in high‐frequency cauterizing element for transurethral resection of the bladder
Authors: KAWAKAMI MASAKO , ISHIKAWA MASAKUNI , FURIHATA MASAYUKI , KONTANI KAZUHIKO , KOBAYASHI SHINYA , IIJIMA KAZUYOSHI , NISHIZAWA OSAMU 
Published: May 2003

AbstractWe successfully treated three patients using the flexible video cystoscope (CYF‐240A, Olympus, Japan) for superficial bladder cancer under local anesthesia and/or spinal anesthesia. The major advantage of this new technique is that surgeons can use digital pictures and high frequency cauterization. This new system provides good quality of life for bladder cancer patients experiencing frequent recurrences.
Performance of Myzus persicae (Hemiptera: Aphididae) clones on different host-plants and their host preference
Authors: Nikolakakis N.N. , Margaritopoulos J.T. , Tsitsipis J.A. 
Published: May 2003

AbstractThe performance of eighteen clones of Myzus persicae (Sulzer) on pepper and tobacco plants at 20°C and L16:D8 and the choice of young adult apterae between tobacco and pepper leaf-discs were examined. The clones were collected from weeds and peach in two tobacco-growing regions: Katerini, northern Greece and Karditsa, central Greece (only from weeds) and from Lehonia, central eastern Greece where tobacco is not cultivated. All clones did well on both hosts. However, the analysis of data revealed a significant effect of ‘region / host plant origin’ on aphid performance. The mean values of adult weight, intrinsic rate of increase and fecundity of the clones collected in Lehonia and reared on tobacco were significantly lower than the observed values for clones from Katerini and Karditsa. Aphids from Lehonia had significantly higher mean values for developmental time on tobacco than clones from the other regions whereas the opposite was observed when aphids were reared on pepper. Aphids collected in Lehonia performed better on pepper than those originating from the tobacco-growing regions. A choice test revealed differences among the clones originating from different regions. Fifty three percent and 43% of aphids from weeds and peach from Lehonia, respectively, chose pepper. By comparison 41.5% and 40.0% of aphids from peach and weeds from Katerini, respectively and 49.5% of aphids from Karditsa preferred tobacco. The results are discussed in relation to host specialization in M. persicae.