bluuebunny/crossref_metadata_2025 huggingface dataset:
Ectomycorrhizal fungal communities at forest edges
Authors: A. DICKIE IAN , REICH PETER B.
Published: March 2005

Ectomycorrhizal fungi are spatially associated with established ectomycorrhizal vegetation, but the influence of distance from established vegetation on the presence, abundance, diversity and community composition of fungi is not well understood.

We examined mycorrhizal communities in two abandoned agricultural fields in Minnesota, USA, using Quercus macrocarpa seedlings as an in situ bioassay for ectomycorrhizal fungi from 0 to 20 m distance from the forest edge.

There were marked effects of distance on all aspects of fungal communities. The abundance of mycorrhiza was uniformly high near trees, declined rapidly around 15 m from the base of trees and was uniformly low at 20 m. All seedlings between 0 and 8 m distance from forest edges were ectomycorrhizal, but many seedlings at 16–20 m were uninfected in one of the two years of the study. Species richness of fungi also declined with distance from trees.

Different species of fungi were found at different distances from the edge. ‘Rare’ species (found only once or twice) dominated the community at 0 m, Russula spp. were dominants from 4 to 12 m, and Astraeus sp. and a Pezizalean fungus were abundant at 12 m to 20 m. Cenococcum geophilum, the most dominant species found, was abundant both near trees and distant from trees, with lowest relative abundance at intermediate distances.

Our data suggest that seedlings germinating at some distance from established ectomycorrhizal vegetation (15.5 m in the present study) have low levels of infection, at least in the first year of growth. Distance from established vegetation represents an important gradient for ectomycorrhizal fungi, with different species occupying distinct niches along this gradient. This provides support for niche differentiation as a factor contributing to ectomycorrhizal fungal diversity.

Ectomycorrhizal infection of seedlings is spatially complex, with high infection and high fungal diversity near trees, high infection but lower diversity at intermediate distances, and low infection and low fungal diversity distant from trees. This spatial complexity should be considered as a factor potentially influencing the establishment of ectomycorrhizal vegetation.
Variation in growth pattern and response to slug damage among native and invasive provenances of four perennial Brassicaceae species
Authors: BUSCHMANN H. , EDWARDS P.J. , DIETZ H.
Published: March 2005

The EICA (evolution of increased competitive ability) hypothesis suggests that release from natural enemies and pathogens results in higher vigour of invasive plants as a result of the selection of less defended but rapidly growing genotypes. Slug diversity and abundance appear to be low in North America compared with Europe, and we therefore hypothesized that release from slug herbivory contributes to the invasiveness of European Brassicaceae species in North America.

In common garden and glasshouse experiments we compared life history and fitness parameters in native (NP) and introduced (IP) provenances of four invasive Brassicaceae species (Barbarea vulgaris, Bunias orientalis, Cardaria draba, Rorippa austriaca) that were subjected to herbivory by Arion lusitanicus. In climate chamber bioassays we investigated slug damage to seedlings and leaf discs using the same sources of plant material.

In all species except B. orientalis we found significant but not always consistent differences in growth and reproductive characteristics between IP and NP plants. Plants of B. vulgaris and R. austriaca from the introduced range had a considerably higher growth rate than those from the native range. While IP plants of the non‐clonal B. vulgaris allocated more resources to seed production than NP plants, the IP plants of the clonal R. austriaca showed a decreased number of seeds.

Contrary to expectation, there were no differences between NP plants and IP plants in the number of damaged leaves and leaf area consumed by slugs, or in the proportion of seedlings damaged and killed. Nor were there interaction effects between slug treatments and provenance.

The results suggest that there are genetically based differences in growth and reproductive parameters between NP and IP plants. As there were no differences in herbivore damage between the provenances, this genetic differentiation is probably due to factors such as competition rather than herbivore effects.

In order to make progress in understanding why some species become invasive, more comparative experimental studies are needed that investigate how different kinds of antagonists (generalist and specialist herbivores and pathogens) influence the performance of plants at different life stages.
Bacterial Endotoxin (lipopolysaccharide) Stimulates Interleukin‐6 Production and Inhibits Growth of Pituitary Tumour Cells Expressing the Toll‐Like Receptor 4
Authors: Tichomirowa M. , Theodoropoulou M. , Lohrer P. , Schaaf L. , Losa M. , Uhl E. , Lange M. , Arzt E. , Stalla G. K. , Renner U.
Published: March 2005

Members of the Toll receptor (Tlr) family have a crucial role in the innate immune response following bacterial infection. The effects of Gram‐negative bacteria‐derived endotoxins (lipopolysaccharide, LPS) are predominantly mediated by Tlr4, and we have recently shown that pituitary folliculostellate cells express functional Tlr4. In the present study, we investigated whether Tlr4 is also present in normal and transformed endocrine epithelial pituitary cell types. By reverse transcriptase‐polymerase chain reaction, Tlr4 mRNA expression was found in some pituitary epithelial tumour cell lines (AtT20, HP75), whereas others were negative (GH3, αT3‐1). Tlr4 protein was detected by immunohistochemistry in a few epithelial cells in normal human anterior pituitaries and in 26 out of 67 human pituitary tumours analysed. LPS had no effect on adrenocorticotropic hormone secretion in Tlr4‐positive AtT20 cells, but it suppressed the growth of these cells in a dose‐dependent manner. As expected, neither hormone secretion, nor growth of Tlr4‐negative GH3 cells was affected by LPS. In cell cultures of Tlr4‐positive pituitary adenomas, LPS dose‐dependently stimulated the production of interleukin (IL)‐6, which is known to induce growth and hormone production in pituitary tumours. The LPS‐induced IL‐6 production was blocked by the specific p38αMAP kinase inhibitor, SB203580, and by the synthetic glucocorticoid, dexamethasone. The data suggest that, during Gram‐negative bacteria‐induced infections or inflammatory processes, LPS could affect pituitary tumour pathophysiology and progression in the subset of Tlr4‐expressing pituitary adenomas.
Oestradiol Effect on Galanin‐Immunoreactive Neurones in the Diencephalon of the Ewe
Authors: Tourlet S. , Ziyazetdinova G. , Caraty A. , Tramu G. , Delsol G. , Tillet Y.
Published: March 2005

Galanin is a neuropeptide involved in the regulation of numerous functions such as reproduction. In female rats, this peptide stimulates gonadotropin‐releasing hormone (GnRH)/luteinizing hormone release and its synthesis is stimulated by oestradiol. It could therefore be an intermediary between the oestrogenic signal from the ovaries and the GnRH neurones (e.g. during the time course leading to the preovulatory GnRH surge). However, although the involvement of galanin is well‐known in rodents, it is poorly understood in ewes. Using immunohistochemistry with a specific antigalanin antiserum, we detected the peptide in neurones of two groups of ovariectomized ewes treated for 6 h with subcutaneous implants, either with oestradiol (experimental group) or empty (control group). The galanin‐immunoreactive neurones were counted in three areas, the preoptic area, the bed nucleus of the stria terminalis and the infundibular nucleus, using a computerized image analysis system. There was no change in the mean number of galanin‐immunoreactive (GAL‐ir) neurones in the infundibular nucleus (37 ± 12 neurones/section in treated animals and 31 ± 11 in controls) or in the bed nucleus of the stria terminalis (22 ± 5 neurones/section in treated animals and 16 ± 4 in controls), but the number of GAL‐ir neurones was higher in the preoptic area in treated than in control ewes (35 ± 4 versus 14 ± 10, P < 0.001). To determine whether the neurones of the preoptic area were directly sensitive to oestradiol, we performed double immunohistochemical labelling for oestradiol receptor alpha and galanin. More than 50% of the GAL‐ir neurones contained the oestradiol receptor alpha and therefore could be directly regulated by oestradiol. These results indicate that oestradiol might act directly on a GAL‐ir neuronal population situated in the preoptic area, without any effect on the GAL‐ir neurones of the infundibular nucleus or the bed nucleus of the stria terminalis. Because a 6‐h oestradiol treatment can induce a preovulatory GnRH surge in ewes, the GAL‐ir neuronal population of the preoptic area might be one of the neuronal systems by which oestradiol activates the GnRH neurones. However, although the morphological relationships between galanin and GnRH neurones have been described in rodents, they remain to be demonstrated in the ewe.
A bacterial hormone (the SCB1) directly controls the expression of a pathway‐specific regulatory gene in the cryptic type I polyketide biosynthetic gene cluster of Streptomyces coelicolor
Authors: Takano Eriko , Kinoshita Hiroshi , Mersinias Vassilis , Bucca Giselda , Hotchkiss Graham , Nihira Takuya , Smith Colin P. , Bibb Mervyn , Wohlleben Wolfgang , Chater Keith
Published: March 2005

Gamma‐butyrolactone signalling molecules are produced by many Streptomyces species, and several have been shown to regulate antibiotic production. In Streptomyces coelicolor A3(2) at least one γ‐butyrolactone (SCB1) has been shown to stimulate antibiotic production, and genes encoding proteins that are involved in its synthesis (scbA) and binding (scbR) have been characterized. Expression of these genes is autoregulated by a complex mechanism involving the γ‐butyrolactone. In this study, additional genes influenced by ScbR were identified by DNA microarray analysis, and included a cryptic cluster of genes for a hypothetical type I polyketide. Further analysis of this gene cluster revealed that the pathway‐specific regulatory gene, kasO, is a direct target for regulation by ScbR. Gel retardation and DNase I footprinting analyses identified two potential binding sites for ScbR, one at −3 to −35 nt and the other at −222 to −244 nt upstream of the kasO transcriptional start site. Addition of SCB1 eliminated the DNA binding activity of ScbR at both sites. The expression of kasO was growth phase regulated in the parent (maximal during transition phase), undetectable in a scbA null mutant, and constitutively expressed in a scbR null mutant. Addition of SCB1 to the scbA mutant restored the expression of kasO, indicating that ScbR represses kasO until transition phase, when presumably SCB1 accumulates in sufficient quantity to relieve kasO repression. Expression of the cryptic antibiotic gene cluster was undetectable in a kasO deletion mutant. This is the first report with comprehensive in vivo and in vitro data to show that a γ‐butyrolactone‐binding protein directly regulates a secondary metabolite pathway‐specific regulatory gene in Streptomyces.
Understanding the control of Pseudomonas aeruginosa alginate synthesis and the prospects for management of chronic infections in cystic fibrosis
Authors: Ramsey Deborah M. , Wozniak Daniel J.
Published: March 2005

Decades of research have been dedicated to the study of the opportunistic pathogen Pseudomonas aeruginosa, a Gram‐negative, environmental bacterium that secretes the exopolysaccharide alginate during chronic lung infection of cystic fibrosis (CF) patients. Although P. aeruginosa utilizes a variety of factors to establish a successful infection in the lungs of CF patients, alginate has stood out as one of the best‐studied prognostic indicators of chronic lung infection. While the genetics, biosynthesis and regulation of alginate are well understood, questions still remain concerning its role in biofilm development and its potential as a therapeutic target. The purpose of this review is to provide a brief summary of alginate biosynthesis and regulation, and to highlight recent discoveries in the areas of alginate production, biofilm formation and vaccine design. This information is placed in context with a proposed P. aeruginosa infectious pathway, highlighting avenues for the use of existing therapies as well as the potential for novel agents to reduce or eliminate chronic infections in CF patients.
Regulation of azole drug susceptibility by Candida albicans protein kinase CK2
Authors: Bruno Vincent M. , Mitchell Aaron P.
Published: March 2005

Fluconazole resistance of the fungal pathogen Candida albicans can arise through several mechanisms, but the responsible genes and pathways are poorly understood. We report here that mutations in CKA2, identified through an insertional mutagenesis screen, confer fluconazole resistance. CKA2 and its homologue CKA1 specify catalytic subunits of protein kinase CK2. Although cka1 mutations have little effect on fluconazole resistance, CKA1 overexpression suppresses the fluconazole resistance of a cka2 mutant. This observation, along with synthetic cka1–cka2 interactions, argues that Cka1p and Cka2p carry out similar functions. cka2 mutants overexpress CDR1 and CDR2, two fluconazole efflux transporter genes, and a cdr1 mutation decreases resistance of a cka2 mutant, as expected if CDR1 and CDR2 overexpression is responsible for fluconazole resistance of the cka2 mutant. The protein phosphatase calcineurin is required for azole tolerance, and we find that the calcineurin inhibitor cyclosporin reverses fluconazole resistance of cka2 mutants. In addition, a mutation in CRZ1, which specifies a homologue of the Saccharomyces cerevisiae transcription factor that is a major target of calcineurin, suppresses fluconazole resistance  of  cka2 mutants.  Expression  analysis  of Cka2p‐responsive genes argues that Cka2p and Crz1p act through distinct mechanisms. Several clinical fluconazole‐resistant isolates overexpress some Cka2p‐responsive genes. We suggest that a Cka2p‐dependent regulatory pathway is altered by clinically derived azole resistance mutations.
Evaluation of Usefulness of Daily Mean Temperature Studies on Impact of Climate Change
Authors: Chauhan S. , Khandelwal R. S. , Prabhu K. V. , Sinha S. K. , Khanna‐Chopra R.
Published: March 2005

The impact of global warming on rise in temperature in different regions has often been expressed as a change in mean temperature (Tmean). The recent results suggest that this change could be both in diurnal and interannual temperatures. Therefore it is important to assess the impact of diurnal variation with the same mean temperature on crop plants for understanding the impact of climate change on agriculture, and also assess the possibility of genetic variation in adaptation. The present study in wheat (Triticum aestivum) varieties examines the effect of varying Tmax and Tmin, while maintaining the same mean temperature on phenology, growth and productivity. The mean temperatures examined are 18 °C with Tmax/Tmin combination of 18/18, 20/16, 22/14 and 24/12 °C. These wheat varieties differed considerably in their response to varying Tmax and Tmin with respect to days to ear emergence, anthesis, biomass accumulation and grain yield. The wheat variety HD2329, a popular Mexican dwarf high yielding cultivar showed maximum adaptation in the temperature combinations examined. The results suggest the need to refine the crop ideotypes in the context of the changing global scenario. This may require detailed experimental studies on various phenological phases. Such studies would help in assessing genotypes which may be having adaptation and thus identify the potential donors for further improvement of crops.
Remobilization of Nitrogen and Carbohydrate from Stems of Bread Wheat in Response to Heat Stress during Grain Filling
Authors: Tahir I. S. A. , Nakata N.
Published: March 2005

When wheat (Triticum aestivum L.) is grown under heat‐stress conditions during grain filling, preanthesis stored total non‐structural carbohydrates (TNC) and nitrogen (N) could serve as alternative source of assimilates. This study was performed to evaluate wheat genotypes for their ability to accumulate and remobilize TNC and N stored in their stem to support grain filling under heat stress. Eighteen genotypes were used for N remobilization study while nine of them were used for TNC remobilization study. They were grown in pots and placed in a vinyl house with the maximum temperature kept below 30 °C. Five days after anthesis (5DAA), half of the pots were taken to phytotrons where temperature was gradually increased and the maximum was set at 38 °C. Grain yield and grain weight decreased by about 35 % under heat stress. Significant differences were found among genotypes in percentage reduction in grain yield, grain weight, grain filling duration and harvest index because of heat stress. The N and TNC concentrations of the stem at 5DAA were significantly different among genotypes. Heat stress significantly reduced the N remobilization efficiency of most of genotypes. However, heat stress significantly increased TNC remobilization efficiency and significant variation were observed among genotypes. N remobilization efficiency across treatments significantly correlated with grain yield, grain weight, harvest index and grain filling duration. TNC at 5DAA negatively correlated with N at 5DAA and harvest index, but the TNC remobilization efficiency under heat stress positively correlated with mainstem grain yield, grain weight and harvest index. The rate of chlorophyll loss from flag leaf positively correlated with N and TNC remobilization efficiencies under heat stress suggesting a link between leaf senescence and remobilization efficiency. The results indicate that heat stress negatively affected grain yield, its components and N remobilization while it increased TNC remobilization because of the increasing demand for resources.
Increased Yield and Revenue with a Seedling Transplanting System for Hybrid Seed Production in Bt Cotton
Authors: Dong H. Z. , Li W. J. , Tang W. , Li Z. H. , Zhang D. M.
Published: March 2005

Rapid adoption of Bacillus thuringiensis (Bt) transgenic hybrid cotton (Gossypium hirsutum L.) in China is greatly attributed to high‐quality hybrid seed produced in northern Shandong cotton production area; however, seed yield has reached a plateau in this area in recent years. Shifting the growing season earlier in the year by planting earlier in a greenhouse‐like hut and transplanting the raised seedlings to the open fields later may allow the crop to produce more seeds. Four‐year consecutive experiments conducted in Huimin County (northern Shandong, China) showed that early‐season chilling stress on seedlings was avoided in such a hut, and that the blooming period was extended by about 1 week longer and the peak blooming occurred 5 days earlier in the year in the transplanting system than in the normal planting system. The number of early‐season blooms and the number of bolls retained per unit area in transplanting system were significantly higher than those in normal planting system, but there were no significant differences in boll size and lint percentage between the two planting systems. Seed yield and quality parameters were significantly improved in the transplanting system through the increased number of bolls per square metre and earlier blooming respectively. As a result of improvement in seed yield and quality, the net revenue for seed producers with the transplanting system was increased by 20.8 and 22.5 % in 2002 and 2003, respectively, compared with the corresponding net revenue in the normal planting system. Seedling transplanting is a potent way to enhance hybrid seed production in Bt transgenic cotton.
Winter Wheat Cultivar Responses to Fungicide Application are Affected by Nitrogen Fertilization Rate
Authors: Varga B. , Svečnjak Z. , Maćešić D. , Uher D.
Published: March 2005

Foliar fungicides are important management inputs for winter wheat (Triticum aestivum L.) in high‐yielding areas of Europe, but their effectiveness may interact with cultivar selection and nitrogen (N) fertilization. No information is available on the potential use of fungicides in reducing yield losses from foliar diseases in Croatia, where wheat crop is extensively grown under low N inputs. Field experiments were conducted during 2000–02 to evaluate the agronomic responses of six winter wheat cultivars to fungicide application (tebuconazol around heading) compared with untreated plots at low (67 kg N ha−1) and high (194 kg N ha−1) N fertilization rates. Grain yields tended to increase in all years following fungicide treatment at high N rate by an average of 10.1 % (773 kg ha−1), but improved significantly in one year only at low N rate. When these occurred, yield increases were associated with larger grain weight per ear primarily due to heavier 1000‐kernel weight. Cultivars differed in their responses to fungicide application across growing seasons and N fertilization rates. Under low disease pressure in 2000 and 2001, improved yields with fungicide use occurred for few susceptible cultivars only, whereas all cultivars significantly increased yields under higher disease severity in 2002 by an average of 383 kg ha−1 (5.0 %) at low N rate and 1443 kg ha−1 (19.0 %) at high N rate. Following fungicide application at high N rate, some susceptible cultivars outyielded resistant cultivars, whereas opposite responses occurred in untreated plots. High N fertilization rate consistently produced larger grain yields except under high disease severity and no fungicide sprayed in 2002, when it had no benefits at all over low N rate. Fungicide application showed limited importance for wheat performance at low N rate; however, cultivars significantly differed in yield responses as well as in rankings after fungicide use at high N fertilization rate.
A Comparison of Methods Used to Determine Biomass on Naturalized Swards
Authors: Martin R. C. , Astatkie T. , Cooper J. M. , Fredeen A. H.
Published: March 2005

An experiment was conducted in 2000 to compare simple visual estimate, sward height and rising plate meter (RPM) methods for determining forage biomass in mixed‐species, naturalized, rotationally grazed dairy and beef pastures. Measurements were taken pre‐ and post‐grazing on 10 sampling dates at the dairy pasture, and post‐grazing at 13 sampling dates at the beef pasture. For each sampling date, the effectiveness of each method for estimating the actual biomass from a quadrat was evaluated using regression analysis. The results for the visual estimate method were not consistent, with non‐linear relationships occurring early and late in the season. While the meter stick was most effective in the dairy pasture, the RPM was most effective in the beef pasture. Species composition and structural characteristics of the stand were important factors affecting accuracy of biomass estimation. Equations developed for each method and site using data from all dates had low R2‐adjusted values, and were unreliable predictors of biomass. The results from individual sites and dates were extremely variable, with no single method effective in all circumstances. To estimate forage biomass in mixed‐species, naturalized pastures, standard quadrat harvesting remains the most reliable method, provided that enough quadrats are clipped to adequately represent a given area.
Validation of Impact of Events Scale in nurses under threat of contagion by severe acute respiratory syndrome
Authors: CHEN CHENG‐SHENG , YANG PINCHEN , YEN CHENG‐FANG , WU HSIU‐YUEH
Published: March 2005

Abstract  The purpose of the present study was to validate the Impact of Events Scale (IES) in a sample of nurses working under threat of severe acute respiratory syndrome (SARS). The internal consistency, construct validity and convergent validity of the instrument were examined in a sample of 128 nurses during the SARS outbreak in Taiwan. Principal component analysis followed by a quartimax rotation were used to derive a two‐factor solution, labeled intrusion (factor 1) and avoidance (factor 2), with both factors accounting for 50.7% of the explained variance. The total Cronbach's α of 0.90 reflected the good internal consistency of the instrument. Correlation with the Symptoms Checklist 90‐R demonstrated the convergent validity of the IES. In conclusion, the IES can be used as a convenient, reliable and valid instrument for evaluation of the psychological distress of nurses working with the highly contagious disease.
Predicting features of later development of schizophrenia among patients with acute and transient psychotic disorder
Authors: SUDA KIYOKO , HAYASHI NAOKI , HIRAGA MASAJI
Published: March 2005

Abstract  It is acknowledged that a considerable proportion of patients who have an episode of acute and transient psychotic disorder (ATPD), will develop schizophrenia after the episode is remitted. If features discriminating the patients who later developed schizophrenia from those who underwent a monomorphous ATPD‐only course are discerned, they may be useful for predicting the prognosis. The authors performed a chart review study of those who were hospitalized with the diagnosis of ATPD and followed up thereafter for >5 years and compared two subject groups: 10 later‐schizophrenia‐developing (SD) patients and 15 non‐schizophrenia‐developing (non‐SD) patients. Assessment of the subjects, conducted by two psychiatrist raters blind to the subject groups, included frequency of ATPD episodes, adaptation levels and life events before admission, and psychiatric symptoms before and after admission. The interrater reliability of the assessment proved to be favorable. As a result, early recurrence of psychotic episodes in the follow‐up period, lack of acute upsurge of insomnia in an early phase of the episode and poor premorbid heterosexual relations characterized the SD patients. The result indicated heterogeneity of ATPD episodes.
Comparison of childhood disintegrative disorder and disintegrative psychosis not diagnosed as childhood disintegrative disorder
Authors: KURITA HIROSHI , KOYAMA TOMONORI , OSADA HIROKAZU
Published: March 2005

Abstract  To clarify the difference of Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM‐IV) childhood disintegrative disorder (CDD) from International Classification of Diseases (9th revision; ICD‐9) disintegrative psychosis (DP), 10 CDD children (mean age, 7.7 years) and 18 DP children (mean, 6.5 years) not diagnosed as CDD divided into DSM‐IV autistic disorder (DP‐AD; n = 11) and pervasive developmental disorders not otherwise specified (DP‐PDDNOS; n = 7) were compared on 31 variables not directly related to the normalcy before regression. The CDD, DP‐AD, and DP‐PDDNOS groups did not differ significantly in 28 variables. The DP‐PDDNOS group met significantly a smaller number of items in criterion A of DSM‐IV autistic disorder criteria than the CDD and DP‐AD groups, both of which did not differ significantly in this respect. The CDD group tended to be more abnormal in auditory responsiveness and verbal communication than the DP‐PDDNOS group. While CDD is distinct from DP‐PDDNOS, its validity apart from AD with regression remains to be studied.
Influence of duration of untreated psychosis on auditory P300 in drug‐naive and first‐episode schizophrenia
Authors: WANG JIJUN , HIRAYASU YOSHIO , HOKAMA HIROTO , TANAKA SHIN , KONDO TSUYOSHI , ZHANG MINGDAO , XIAO ZEPING
Published: March 2005

Abstract  P300 amplitude reduction in schizophrenia is, according to previous studies, partially recovered by treatment with neuroleptics. However, whether this medication‐induced P300 recovery is associated with duration of untreated psychosis (DUP) remains unreported; the present study is a preliminary examination of this question. Auditory P300 was recorded from 18 drug‐naive and first‐episode schizophrenia patients, among whom 10 were identified as short DUP, and eight as long DUP. Follow‐up event‐related potential tests were carried out after treatment with haloperidol or bromperidol for approximately 2 months. Recovery of P300 amplitude was replicated after neuroleptic medication was administered. A significant interaction was found between DUP and the medication effect in P300 amplitude over the left temporo‐parietal area; a significant P300 recovery was seen in short DUP but not in long DUP. These results suggest that first‐episode schizophrenia patients with long DUP might have severe impairments in the left temporal structures, supporting DUP as a key variable in future neurobiological studies of first‐episode schizophrenia.
Obsessive‐compulsive symptoms in clozapine‐treated schizophrenic patients
Authors: ERTUGRUL AYGUN , YAGCIOGLU A. ELIF ANIL , ENI NURHAYAT , YAZICI KÂZIM M.
Published: March 2005

Abstract  The aim of the present study was to assess the occurence of obsessive‐compulsive symptoms (OCS) in schizophrenic patients treated with clozapine, and to examine the relationship between OCS and other clinical variables. The results support earlier findings which suggest that clozapine produces or unmasks OCS. In addition, the severity of OCS was not related to other dimensions of psychopathology, severity of illness, clinical improvement or dose and duration of clozapine treatment.
Does intraspecific niche partitioning in a native predator influence its response to an invasion by a toxic prey species?
Authors: WEBB JONATHAN K. , SHINE RICHARD , CHRISTIAN KEITH A.
Published: March 2005

Abstract  The introduced and highly toxic cane toad (Bufo marinus) is rapidly spreading across northern Australia where it may affect populations of large terrestrial vertebrate predators. The ecological impact of cane toads will depend upon the diets, foraging modes and habitat use of native predators, and their feeding responses to cane toads. However, intraspecific niche partitioning may influence the degree of vulnerability of predators to toxic prey, as well as the time course of the impact of alien invaders on native species. We studied the diet of the northern death adder Acanthophis praelongus and their feeding responses to cane toads. In the laboratory, death adders from all size classes and sexes readily consumed frogs and cane toads. Diets of free ranging A. praelongus from the Adelaide River floodplain were more heterogeneous. Juvenile snakes ate mainly frogs (39% of prey items) and small scincid lizards (43%). Both sexes displayed an ontogenetic dietary shift from lizards to mammals, but adult males fed on frogs (49%) and mammals (39%) whereas adult females (which grew larger than males) fed mainly on mammals (91%) and occasionally, frogs (9%). Feeding rates and body condition of adult snakes varied temporally and tracked fluctuations in prey availability. These results suggest that cane toads may negatively affect populations of northern death adders in the Darwin region. However, we predict that different size and sex classes of A. praelongus will experience differential mortality rates over different timescales. The initial invasion of large toads may affect adult males, but juveniles may be unaffected until juvenile toads appear the following year, and major affects on adult female death adders may be delayed until annual rainfall fluctuations reduce the availability of alternative (rodent) prey.
Edge effects on fauna in fragmented seagrass meadows
Authors: TANNER JASON E.
Published: March 2005

Abstract  Fragmented habitats are a common occurrence in many marine systems, but remain poorly studied in comparison to their terrestrial counterparts. Here, I show that crustaceans inhabiting fragmented Zostera seagrass meadows show a dramatic response (change in abundance) to patch edges, with 11 out of 12 tests showing greatest abundance at the boundary between sand and seagrass. These patterns occurred on a scale of 0.25–1 m around the patch edge. Changes in seagrass biomass are unlikely to explain this pattern, as seagrass biomass increased smoothly at the patch edge, and did not decline towards patch interiors. In contrast to crustaceans, only a few polychaete taxa responded to the patch edge (9 of 25 tests), and bivalves generally did not show a response (1 of 5 tests). These latter groups are predominantly infaunal, and their lack of response may be partly due to the presence of substantial quantities of seagrass root and rhizome material in the sand habitat, which was defined visually based on the lack of above‐ground seagrass components only.
Regulation of Homer and group I metabotropic glutamate receptors by nicotine
Authors: Kane J. K. , Hwang Y. , Konu O. , Loughlin S. E. , Leslie F. M. , Li M. D.
Published: March 2005

The present study focuses on the nicotine‐induced modulation of mRNA and protein expression of a number of genes involved in glutamatergic synaptic transmission in rat brain over different time periods of exposure. A subchronic (3 days) but not the chronic (7 or 14 days) administration of nicotine resulted in the up‐regulation of Homer2a/b mRNA in the amygdala while in the ventral tegmental area (VTA) no change in expression of either Homer2a/b or Homer1b/c was observed. Although the increase in Homer2a/b mRNA was not translated into the protein level in the amygdala, a slight but significant up‐regulation of Homer1b/c protein was observed in the same region at day 3. Both Homer forms were up‐regulated at the protein level in the VTA at day 3. In the nucleus accumbens, 14 days of nicotine treatment up‐regulated mRNA of Homer2b/c by 68.2% (P < 0.05), while the short form Homer1a gene was down‐regulated by 65.0% at day 3 (P < 0.05). In regard to other components of the glutamatergic signalling, we identified an acute and intermittent increase in the mRNA and protein levels of mGluR1 and mGluR5 in the amygdala. In the VTA, however, the effects of nicotine on mGluR mRNA expression were long‐lasting but rather specific to mGluR1. Nevertheless, mGluR1 protein levels in the VTA area were up‐regulated only at day 3, as in the amygdala. These data provide further evidence for the involvement of nicotine in the glutamatergic neuronal synaptic activity in vivo, suggesting a role for the newly identified Homer proteins in this paradigm.
Voltage‐gated calcium channels play crucial roles in the glutamate‐induced phase shifts of the rat suprachiasmatic circadian clock
Authors: Kim Do Young , Choi Hee Joo , Kim Jeong Sook , Kim Yoon Sik , Jeong Do Ung , Shin Hyung Cheul , Kim Mi Jin , Han Hee‐Chul , Hong Seung Kil , Kim Yang In
Published: March 2005

The resetting of the circadian clock based on photic cues delivered by the glutamatergic retinohypothalamic tract is an important process helping mammals to function adaptively to the daily light–dark cycle. To see if the photic resetting relies on voltage‐gated Ca2+ channels (VGCCs), we examined the effects of VGCC blockers on the glutamate‐induced phase shifts of circadian firing activity rhythms of suprachiasmatic nucleus (SCN) neurons in hypothalamic slices. First, we found that a cocktail of amiloride, nimodipine and ω‐conotoxin MVIIC (T‐, L‐ and NPQ‐type VGCC antagonists, respectively) completely blocked both phase delays and advances, which were, respectively, induced by glutamate application in early and late night. Next, we discovered that: (i) amiloride and another T‐type VGCC antagonist, mibefradil, completely obstructed the delays without affecting the advances; (ii) nimodipine completely blocked the advances while having less impact on delays; and (iii) ω‐conotoxin MVIIC blocked largely, if not entirely, both delays and advances. Subsequent whole‐cell recordings revealed that T‐type Ca2+ currents in neurons in the ventrolateral, not dorsomedial, region of the SCN were larger during early than late night, whereas L‐type Ca2+ currents did not differ from early to late night in both regions. These results indicate that VGCCs play important roles in glutamate‐induced phase shifts, T‐type being more important for phase delays and L‐type being so for phase advances. Moreover, the results point to the possibility that a nocturnal modulation of T‐type Ca2+ current in retinorecipient neurons is related to the differential involvement of T‐type VGCC in phase delays and advances.
The effect of aging on the subcellular distribution of estrogen receptor‐alpha in the cholinergic neurons of transgenic and wild‐type mice
Authors: Kalesnykas Giedrius , Roschier Ulla , Puoliväli Jukka , Wang Jun , Miettinen Riitta
Published: March 2005

The degeneration of the basal forebrain cholinergic system plays an important role in cognitive deterioration in aging and Alzheimer's disease. Brain cholinergic neurons and their projections are affected by changes in the circulating levels of estrogens, which exert their effects mainly through the estrogen receptors. In this study, we investigated the effect of aging, estrogen status and transgenic genotype on the number of cholinergic neurons and the estrogen receptor alpha (ERα) content in the medial septum–vertical limb of the diagonal band of Broca. We used 6‐ and 12‐month‐old female double transgenic mice carrying mutated human amyloid precursor protein (APPswe) and presenilin‐1 (PS1‐A246E), and their nontransgenic littermate controls, which had been sham‐operated or ovariectomized at the age of 3 months. Brain sections were double immunostained for choline acetyltransferase (ChAT) and ERα and used for stereological cell counting. We found that the number of ChAT‐immunoreactive (ir) neurons containing nuclear ERα‐ir was significantly lower in 12‐ than in 6‐month‐old mice. However, the age of the mice, the transgenic genotype or ovariectomy had no effect on the total number of ChAT‐ir neurons, or on the number and percentage of all ChAT‐ir neurons that contained ERα. These results indicate that aging is associated with translocation of ERαs from the nucleus to the cytoplasm. We propose that this phenomenon is linked to those age‐related processes known to be involved in inhibiting ERα binding to nuclei.
Balanced inhibition and excitation underlies spike firing regularity in ventral cochlear nucleus chopper neurons
Authors: Paolini Antonio G. , Clarey Janine C. , Needham Karina , Clark Graeme M.
Published: March 2005

Ventral cochlear nucleus stellate cells respond to characteristic frequency (CF) tones with sustained (CS), transient (CT) or onset chopping (OC) activity. The mechanisms underlying these different response patterns are not fully understood, and the present study used in vivo intracellular recordings (n = 42) in urethane‐anaesthetized rats to examine the possible influence of inhibition on action potential regularity. Hyperpolarization following the offset of a CF tone burst was used as a measure of on‐CF inhibition. A cluster analysis based on several membrane potential features, including on‐CF inhibition, discriminated three groups in addition to the CS response type − two types of CT responses and the OC type. The different patterns of firing regularity exhibited by CS/T neurons reflected different thresholds or degrees of overlap between these cells' narrowly tuned excitatory and inhibitory inputs. CT cells with closely matched inhibitory and excitatory response areas showed substantial on‐CF inhibition and the greatest decline in firing regularity during a CF tone, whereas those with a mismatch between their response areas showed lateral inhibition and a less marked decline in firing regularity. The presence of inhibition in CS neurons did not alter their firing regularity, possibly because of the lower threshold for excitation compared with inhibition. The latency, duration and frequency extent of sustained hyperpolarization in CS/T cells is inconsistent with the response properties of OC neurons, suggesting that another source(s) of inhibition influences firing regularity, and presumably response magnitude, in these neurons.
Serotonin refines the locomotor‐related alternations in the in vitro neonatal rat spinal cord
Authors: Pearlstein E. , Ben Mabrouk F. , Pflieger J. F. , Vinay L.
Published: March 2005

Serotonergic projections from raphe nuclei arrive in the lumbar enlargement of the spinal cord during the late fetal period in the rat, a time window during which the locomotor‐related left/right and flexor/extensor coordinations switch from synchrony to alternation. The goal of the present study was to investigate the role played by serotonin (5‐HT) in modulating the left/right and flexor/extensor alternations. Fictive locomotion was induced by bath application of N‐methyl‐d,l‐aspartate (NMA) in the in vitro neonatal rat spinal cord preparation. By means of cross‐correlation analysis we demonstrate that 5‐HT, when added to NMA, improves left/right and flexor/extensor (recorded from the 3rd and 5th lumbar ventral roots, respectively) alternations. This effect was partly reproduced by activation of 5‐HT2A/2C receptors. We then tested the contribution of endogenous 5‐HT to NMA‐induced fictive locomotion. Reducing the functional importance of endogenous 5‐HT, either by inhibiting its synthesis with daily injections of p‐chloro‐phenylalanine (PCPA), starting on the day of birth, or by application of ketanserin (a 5‐HT2 receptor antagonist) or SB269970 (a 5‐HT7 receptor antagonist), disorganized the NMA‐induced locomotor pattern. This pattern was restored in PCPA‐treated animals by adding 5‐HT to the bath. Blocking 5‐HT7 receptors disorganized the locomotor‐like rhythm even in the absence of electrical activity in the brain stem, suggesting that NMA applied to the spinal cord does not cause 5‐HT release by activating a spino‐raphe–spinal loop. These results demonstrate that 5‐HT is critical in improving the locomotor‐related alternations in the neonatal rat.
Mechanisms of ATP action on motor nerve terminals at the frog neuromuscular junction
Authors: Grishin S. , Shakirzyanova A. , Giniatullin A. , Afzalov R. , Giniatullin R.
Published: March 2005

We have shown previously that ATP inhibits transmitter release at the neuromuscular junction through the action on metabotropic P2Y receptors coupled to specific second messenger cascades. In the present study we recorded K+or Ca2+currents in motor nerve endings or blocked K+or Ca2+channels in order to explore the nature of downstream presynaptic effectors. Endplate currents were presynaptically depressed by ATP. Blockers of Ca2+‐activated K+‐channels, such as iberiotoxin, apamin or tetraethylammonium, did not change the depressant action of ATP. By contrast, K+channel blocker 4‐aminopyridine (4‐AP) and raised extracellular Ca2+attenuated the effect of ATP. However, these effects of 4‐AP and high Ca2+were reversed by Mg2+, suggesting Ca2+‐dependence of the ATP action. Ba2+promoted the depressant action of ATP as did glibenclamide, a blocker of ATP‐sensitive K+channels, or mild depolarization produced by 7.5 mmK+. None of the K+channel blockers affected the depressant action of adenosine. Focal recording revealed that neither ATP nor adenosine affected the fast K+currents of the motor nerve endings. However, unlike adenosine, ATP or UTP, an agonist of P2Y receptors, reversibly reduced the presynaptic Ca2+‐current. This effect was abolished by suramin, an antagonist of P2 receptors. Depressant effect of ATP on the endplate and Ca2+‐currents was mimicked by arachidonate, which precluded the action of ATP. ATP reduced acetylcholine release triggered by ionomycin or sucrose, suggesting inhibition of release machinery. Thus, the presynaptic depressant action of ATP is mediated by inhibition of Ca2+channels and by mechanism acting downstream of Ca2+entry.
Correlation between clinical and pathological staging in a series of radical cystectomies for bladder carcinoma
Authors: Ficarra Vincenzo , Dalpiaz Orietta , Alrabi Najati , Novara Giacomo , Galfano Antonio , Artibani Walter
Published: March 2005

OBJECTIVE

To analyse the rate of concordance between the clinical and pathological Tumour‐Nodes‐Metastasis staging systems in a homogeneous series of patients who had undergone radical cystectomy for locally advanced or recurrent multifocal superficial bladder carcinoma.

PATIENTS AND METHODS

The clinical data of 156 patients who had undergone radical cystectomy and bilateral iliaco‐obturator lymphadenectomy for bladder cancer in our department were analysed retrospectively.

RESULTS

The clinical stage of the primary tumour was carcinoma in situ in three patients (1.9%), cT1 in 67 (42.9%), cT2 in 70 (44.9%), cT3 in five (3.2%) and cT4 in nine (5.8%). Clinical lymph node involvement was detected in 19 patients (12.2%). The differences between clinical and pathological stages were statistically significant (P < 0.001), the concordance was moderate (κ = 0.27, P < 0.001). Of the 70 patients with ≤ cT1, 40 (57%) were reconfirmed as having pathological stage ≤ T1; of the 70 with cT2, 16 (23%) had pT2 carcinoma. Of the 140 patients with clinically organ‐confined (≤T2) neoplasms, 70 (50%) had been understaged after radical cystectomy. The clinical and pathological systems were statistically overlapping for locally advanced cases only. Pathological lymph node involvement was diagnosed in 45 patients (28.8%); this was foreseen with pelvic computed tomography in 19 (12%) only (P < 0.001). All patients designated cN+ were also pN+.

CONCLUSION

These data confirm the high risk of clinical understaging of both local extension of the primary tumour and lymph node involvement.
Towards a better understanding of involuntary detrusor activity
Authors: Bradshaw Helen D. , Radley Stephen C. , Rosario Derek J. , Chapple Christopher R.
Published: March 2005

There is a wide spectrum of topics covered in this section. The ever‐present problem of nocturia is further explored by authors from Sweden, with interesting conclusions. In addition, several papers describe various issues relating to the surgical correction of stress urinary incontinence. Finally, authors from Switzerland describe their use of sacral magnetic stimulation in non‐inflammatory chronic pelvic pain syndrome.

OBJECTIVES

To compare the measured variables of involuntary detrusor activity (IDA) during ambulatory cystometry (AC) in women with and with no overactive bladder symptoms, and to evaluate the correlation between these variables and symptom severity.

PATIENTS AND METHODS

In all, 61 symptomatic and 39 asymptomatic women completed the Bristol Female Lower Urinary Tract Symptoms Questionnaire (BFLUTS‐Q) and underwent AC. Measured variables of IDA (amplitude, duration, bladder volume and symptoms) were compared in the two cohorts.

RESULTS

IDA was detected in 47 of 61 symptomatic women (77%) and in 17 of 36 (47%) controls (P ≤ 0.01). The maximum IDA (defined as the highest amplitude contraction in any fill‐void cycle) occurred at significantly lower volumes (328 vs 450 mL, P ≤ 0.05), was of higher amplitude (26 vs 12 cmH2O, P = 0.14) and longer duration (83 vs 14 s, P ≤ 0.05) in symptomatic women than in controls. There was coincident incontinence in 22 (36%) symptomatic women and no controls (P ≤ 0.01). Discriminatory levels for clinically relevant IDA were established, and when applied retrospectively, classified 35 of 61 symptomatic women (55%) and one control (3%) as having such IDA. The correlation between symptom severity (measured by the BFLUTS‐Q) and urodynamics was higher when these criteria were applied (r = 0.52 vs 0.38, P ≤ 0.01).

CONCLUSION

There are quantifiable differences between IDA found during AC in symptomatic and asymptomatic women. The measured variables of IDA may be useful to determine its clinical relevance, which may be indicated by contractions associated with leakage or contractions of >30 s occurring at bladder volumes of <300 mL.