bluuebunny/crossref_metadata_2025 huggingface dataset:
A slipped‐mispairing mutation in AgrA of laboratory strains and clinical isolates results in delayed activation of agr and failure to translate δ‐ and α‐haemolysins
Authors: Traber Katrina , Novick Richard
Published: January 2006

agr is a global regulator of staphylococcal virulence and other accessory gene functions, especially including the haemolysins. Lack of haemolysin production therefore generally represents a defect in agr function. An example of this is Staphylococcus aureus strain RN4220, a widely used laboratory strain that carries a nitrosoguanidine (MNNG)‐induced mutation enabling it to accept DNA from Escherichia coli and other bacteria. We show here that the non‐haemolytic phenotype of RN4220 is caused by an extra A residue in a run of seven As at the 3′ end of agrA (agrA‐8A). This causes a frameshift that results in the addition of three amino acyl residues to the C‐terminal end of the protein. The 8A mutation does not inactivate the agr locus, but rather delays agr activation by 2–3 h, which results in failure to translate α‐ and δ‐haemolysins, and hence, in a non‐haemolytic phenotype. This mutation turned out not to be an adventitious consequence of MNNG mutagenesis, but rather had arisen in RN450, the immediate parent of RN4220. RN450 had become haemolytically heterogeneous in storage, and its non‐haemolytic variants had the 8A mutation. The same mutation was also identified in a clinical isolate in which a non‐haemolytic variant had arisen during the course of infection. Haemolytic activity in the mutant laboratory strains could be restored by the addition of auto‐inducing peptide (AIP) early in growth, indicating that delayed production of RNAIII is responsible for the failure to translate α‐ and δ‐haemolysins. Discovery of the 8A mutation has revealed the basis of the dissociation between agr activity and the non‐haemolytic phenotype of RN4220, and has solved the long‐standing mystery of the variable non‐haemolytic phenotype of its immediate parent, RN450. The occurrence of this mutation in a clinical isolate indicates that it is not simply a laboratory phenomenon, and may represent a naturally occurring mechanism for the modulation of agr activity.
Effects and mechanisms of long‐pulse gastric electrical stimulation on canine gastric tone and accommodation
Authors: Xing J. H. , Chen J. D. Z.
Published: January 2006

Abstract  Gastric electrical stimulation (GES) has been applied to treat gastroparesis and morbid obesity. The aims of this study were to evaluate the sites of stimulation and the mechanisms of GES on gastric tone and accommodation. Gastric tone and accommodation were evaluated with a barostat in surgically prepared dogs. GES was applied at seven different locations, and gastric tone was assessed at each site. The effect of truncal vagotomy on gastric tone and accommodation and the role of the nitrergic pathway were also evaluated. We have found: 1) GES induced varying degrees of gastric relaxation at all tested locations in normal dogs; 2) Gastric volume was also significantly increased with GES in vagotomized dogs and the change tended to be lower than that of normal animals; 3) Gastric accommodation was reduced during GES in both the normal and vagotomized dogs and the reduction tended to be more in the vagotomized animals; 4) The GES‐induced increase in gastric volume was partially abolished by intravenous nitric oxide synthase inhibitor. GES at various sites of the stomach exerts inhibitory effect on gastric tone; the most effective sites are in the antrum along the lesser or greater curvature; the inhibitory effect of GES on gastric tone is partially mediated by the vagal and nitrergic pathway.
Influence of drought, salt stress and abscisic acid on the resistance of tomato to Botrytis cinerea and Oidium neolycopersici
Authors: Achuo E. A. , Prinsen E. , Höfte M.
Published: January 2006

Abiotic stress may affect plant response to pathogen attack through induced alterations in growth regulator and gene expression. Abscisic acid (ABA) mediates several plant responses to abiotic stress. The effects of drought, salt stress and ABA on the interaction of tomato (Lycopersicon esculentum) with the biotrophic fungus Oidium neolycopersici and the necrotrophic fungus Botrytis cinerea were investigated. Drought stress resulted in a twofold increase in endogenous ABA as well as a 50% reduction in B. cinerea infection and a significant suppression of O. neolycopersici on tomato cv. Moneymaker. Salt stress did not affect B. cinerea infection, but significantly reduced infection by O. neolycopersici, with no obvious increase in endogenous ABA. Compared with the wild type, the ABA‐deficient sitiens mutant was more resistant to O. neolycopersici and B. cinerea. Exogenous ABA resulted in increased susceptibility of sitiens to both pathogens, but did not increase the basal susceptibility of wild‐type plants. It is concluded that, in tomato, drought and salt stress stimulate different, but possibly overlapping, pathogen‐defence pathways which may not necessarily involve ABA. Meanwhile, basal endogenous ABA levels suppress the resistance of tomato to O. neolycopersici and B. cinerea, but an ABA increase above the basal level, resulting from exogenous application, does not increase susceptibility to these pathogens.
Expression of an oxalate decarboxylase gene from Flammulina sp. in transgenic lettuce (Lactuca sativa) plants and resistance to Sclerotinia sclerotiorum
Authors: Dias B. B. A. , Cunha W. G. , Morais L. S. , Vianna G. R. , Rech E. L. , de Capdeville G. , Aragão F. J. L.
Published: January 2006

Sclerotinia sclerotiorum causes rot in a broad range of crops including lettuce, soybean, dry bean and tomato. Pathogenesis of Sclerotinia has been associated with the copious production of oxalic acid. Enzymes capable of degrading oxalic acid have been utilized to produce transgenic resistant plants. Transgenic lettuce lines containing the decarboxylase gene (oxdc) isolated from a Flammulina sp. were produced by Agrobacterium‐mediated transformation. Out of 80 regenerated plants, PCR analysis revealed the presence of the oxdc gene in 34 lines. Except for eight lines, the primary transformants transferred the foreign gene to the first generation in a Mendelian fashion. In a detached‐leaf assay inoculated with agar plugs of a 2‐day‐old S. sclerotiorum culture, two lines (P100 and P43) were symptomless, while line P57 showed a delay in symptom development when compared with a nontransgenic control line. RT‐PCR analysis carried out with the resistant lines showed the expression of oxdc gene transcripts.
Impacts of applied Sclerotinia sclerotiorum on the dynamics of a Cirsium arvense population
Authors: BOURDÔT G W , HURRELL G A , SAVILLE D J , LEATHWICK D M
Published: January 2006

A field experiment was conducted from October 1992 to March 1997 in a sheep‐grazed pasture in Canterbury, New Zealand, to determine the effects of the fungus Sclerotinia sclerotiorum on the long‐term dynamics of a population of Cirsium arvense. The pathogen was applied in mid‐spring either once or in three consecutive years when the C. arvense shoots were vegetative rosettes, using a granular, mycelium‐on‐wheat preparation that lodged on the C. arvense leaves, stems and in the leaf axils. The single application caused disease in the C. arvense that was confined to the application year. The disease resulted in a temporary (17 months) reduction in population size through initial mortalities among treated shoots and resultant reductions in root growth, adventitious root bud, subterranean shoot and, subsequently, aerial shoot population sizes. The soil seedbank was 80% lower in the treated plots than in the control plots in the first year. Seedlings were never found. The annually repeated application of S. sclerotiorum did not result in the expected continuing decline in the C. arvense population relative to the control population.
Spectral discrimination of Ridolfia segetum and sunflower as affected by phenological stage
Authors: PEÑA‐BARRAGÁN J M , LÓPEZ‐GRANADOS F , JURADO‐EXPÓSITO M , GARCÍA‐TORRES L
Published: January 2006

Ridolfia segetum is an umbelliferous weed frequent and abundant in sunflower crops in the Mediterranean basin. Field research was conducted to evaluate the potential of hyperspectral and multispectral reflectance and five vegetation indices in the visible to near infrared spectral range, for discriminating bare soil, sunflower and R. segetum at different phenological stages. This was a preliminary step for mapping R. segetum patches in sunflower using remote sensing for herbicide application decisions. Reflectance data were collected at three sampling dates (mid‐May, mid‐June and mid‐July, corresponding to vegetative‐early reproductive, flowering and senescent phenological stages respectively) using a handheld field spectroradiometer. Differences observed in hyperspectral reflectance curves were statistically significant within and between crop and weed phenological stages depending on sampling date, which facilitates their discrimination. Statistically significant differences in the multispectral and vegetation indices analysis showed that it is also possible to distinguish any of the classes studied. Our study provides some information for constructing the spectral libraries of sunflower and R. segetum in which the different phenological stages co‐existing in the field were considered. Hyperspectral and multispectral results suggest that mapping R. segetum patches in sunflower is feasible using airborne hyperspectral sensors, and high‐resolution satellite imagery or aerial photography, respectively, taking into account specific timeframes.
Response to flooding intensity in Elytrigia repens, E. intermedia (Poaceae: Triticeae) and their hybrid
Authors: MAHELKA V
Published: January 2006

Response to flooding intensity in three closely related taxa, Elytrigia repens, E. intermedia and their hybrid was studied. Plants were exposed to three intensities of flooding for a 30‐day period. Response to flooding intensity was estimated by measuring dry mass of the following: total biomass, above‐ground living biomass, above‐ground dead biomass, below‐ground biomass, rhizome and root mass and by the allocation of dry mass into rhizomes and root:shoot ratio. Reduction of nearly all the biomass compartments with increasing flooding intensity was observed in the three taxa. All three taxa can thus be regarded as flood‐intolerant. Based on the parameters measured, E. repens is regarded as the relatively most flooding‐tolerant, E. intermedia as the least tolerant, while the hybrid displayed intermediate flooding tolerance. The higher flooding tolerance in E. repens was likely related to its ability to accumulate a sufficient mass of rhizomes before flooding, due to higher regeneration ability. E. repens also displayed the highest phenotypic plasticity, as deduced from the reaction norms constructed for total biomass and rhizome mass of particular clones of the three taxa studied. This indicates that, on the species level, E. repens is better adapted to changing environmental conditions and it can be expected to colonize flooded soils. Both Elytrigia species also occur as weeds: E. intermedia grows in agricultural environments in warm regions, while E. repens infests many different types of habitats. Where they co‐occur, hybridization between them may lead to the enrichment of their gene pools with genes responsible for survival of the parental species under extreme conditions; their weedy potential may thus be enhanced.
Skin manifestations with Rotavirus infections
Authors: Di Lernia Vito , Ricci Cinzia
Published: January 2006

Rotavirus infection is one the most frequent cause of diarrhea among infants and children. Although it is not associated to specific dermatologic clinical pictures, recently, different clinical manifestations have been reported in association with this infection. They include exanthema, Gianotti–Crosti syndrome, and Acute Infantile Hemorrhagic Edema. The condition can be diagnosed microbiologically with stool cultures. The prognosis is excellent in healthy, immunocompetent individuals.
Melanoma in a long‐standing lesion of chromoblastomycosis
Authors: Gon Airton dos Santos , Minelli Lorivaldo
Published: January 2006

Background  Chromoblastomycosis is a chronic cutaneous fungal infection where the presence of fibrous scars and continuous inflammation might be the propitious condition for the development of malignant neoplasms.

Methods  We report a case of cutaneous melanoma arising on a leg of a man that had been affected by extensive chromoblastomycosis for more than 30 years.

Results  A 70‐year‐old white man presented with an irregularly pigmented lesion over an area of fibrosis and verrucous lesions, previously diagnosed as chromoblastomycosis, on his left ankle. Histological examination showed an acral lentiginous melanoma, Clark level IV, thickness of 2.3 mm. Follow‐up for 7 years showed no signs of recurrence or metastasis.

Conclusions  The association between malignancy and chromoblastomycosis is very uncommon, but medical staff who deal with this disease should be attentive to this possibility, as early detection of these neoplasms will provide an adequate treatment, improving survival and quality of life for those patients.
Superficial thrombophlebitic tuberculide
Authors: Motswaledi Hendrick M. , Schulz E. Joy
Published: January 2006

Background  Tuberculides are the result of immunologic reactions to hematogenously spread antigenic components of Mycobacterium tuberculosis. There are three recognized tuberculides – papulonecrotic tuberculide, erythema induratum of Bazin, and lichen scrofulosorum. In 1997, in Japan, Hara and coworkers reported five patients with what they called “nodular granulomatous phlebitis,” which they proposed was a fourth type of tuberculide. We describe a patient who presented with features identical to those reported by Hara et al. in order to draw attention to the previous report and to support the concept of a fourth tuberculide which clinically resembles superficial thrombophlebitis.

Methods  A black South African man presented with cord‐like thickening of superficial veins on the antero‐medial aspects of the lower legs. Nodular swellings were palpable along the course of these veins. There was no evidence of tuberculosis elsewhere in the body, but the patient had a strongly positive tuberculin reaction. Skin biopsies were performed for histologic examination, culture, and polymerase chain reaction (PCR).

Results  Histologic examination showed a granulomatous infiltrate localized to the veins in the subcutaneous fat. Stains for acid‐fast bacilli and culture were negative, but PCR was positive for M. tuberculosis DNA. The lesions responded promptly to antituberculous therapy.

Conclusions  Our patient showed features identical to those of cases described by Hara and coworkers and assigned as a fourth type of tuberculide. As the lesions clinically resemble superficial thrombophlebitis, we propose the term “superficial thrombophlebitic tuberculide” rather than “nodular granulomatous phlebitis.”
Alopecia areata associated with regression of cutaneous melanoma
Authors: Yousefi Marjan , Payne Joseph R. , Barnhill Raymond L.
Published: January 2006

A 41‐year‐old white female with a past medical history of hypothyroidism and alopecia universalis presented on January 24, 2002 with a recently changing mole. She indicated changes in size and color of the superior aspect of a mole that had been present for more than 8 years. She had approximately 20 lifetime peeling sunburns due to being a lifeguard. No family or previous personal history of skin cancers, including melanoma or atypical nevi, was reported. Her history of alopecia universalis began 12 years previously and has partially resolved with remaining patchy alopecia of the scalp and eyebrows. On diagnosis of alopecia universalis, she was initially treated with oral prednisone for 1 year and topical minoxidil for 3 months. Currently, she is not being treated for this condition. She denied other previous skin conditions. She had a surgical history of tonsillectomy at the age of 7 years. Her current medication includes levothyroxine (0.015 µg) for hypothyroidism diagnosed 12 years previously. She reported no known drug allergies.

During the initial physical examination, she presented with phototype II skin with two adjacent pigmented lesions on her left foot within a 1.3 cm square. The first lesion on the left posterior distal heel was an irregular, brown–black, 0.5 × 0.6 cm macule. The second lesion, on the left posterior proximal heel, was an irregular, brown, speckled, 0.3 × 0.4 cm macule (Fig. 1). The patient had ophiasis of the scalp and total alopecia of the bilateral eyebrows. In keeping with the patient's wishes, alopecia lesions were not biopsied and clinical photographs of the alopecia are not included in this article.

Malignant melanoma of the left foot

image

Two 3 mm punch biopsies were performed within each lesion. The left posterior proximal lesion showed malignant melanoma, with a Breslow depth of 0.4 mm, anatomic level II, marked lymphocytic response and partial regression (Fig. 2). The left posterior distal lesion showed malignant melanoma in situ, arising in a lentiginous compound nevus, with architectural disorder and cytological atypia. These two lesions were concluded to be one lesion with clinical regression.

Invasive malignant melanoma (× 100)

image

She underwent local excision with 1‐cm margins and sentinel lymph node biopsy owing to the presence of regression, which showed no evidence of metastatic melanoma. Lactate dehydrogenase and chest X‐ray were within normal limits. The alopecia areas were not biopsied previously or at that time.
Habitat loss and the structure of plant–animal mutualistic networks
Authors: Fortuna Miguel A. , Bascompte Jordi
Published: January 2006

Recent papers have described the structure of plant–animal mutualistic networks. However, no study has yet explored the dynamical implications of network structure for the persistence of such mutualistic communities. Here, we develop a patch‐model of a whole plant–animal community and explore its persistence. To assess the role of network structure, we build three versions of the model. In the first version, we use the exact network of interactions of two real mutualistic communities. In the other versions, we randomize the observed network of interactions using two different null models. We show that the community response to habitat loss is affected by network structure. Real communities start to decay sooner than random communities, but persist for higher destruction levels. There is a destruction threshold at which the community collapses. Our model is the first attempt to describe the dynamics of whole mutualistic metacommunities interacting in realistic ways.
Factors predisposing to the development of anastomotic strictures in a single‐surgeon series of radical retropubic prostatectomies
Authors: HUANG GEORGE , LEPOR HERBERT
Published: January 2006

OBJECTIVE

To determine the rate of anastomotic stricture (AS) after radical retropubic prostatectomy (RRP) performed by one experienced surgeon, and to identify factors predisposing to its formation.

PATIENTS AND METHODS

In all, 708 men were prospectively monitored for the development of AS after RRP. Potential risk factors for AS were analysed.

RESULTS

There were no significant differences in age, Gleason score, nerve‐sparing status, intraoperative blood loss, degree of extravasation on initial cystography, or duration of the indwelling urinary catheter between men who developed AS and men who did not. The mean postoperative blood loss was significantly higher in men who developed AS. The incidence of AS was also significantly higher in men whose bladder necks were reconstructed more narrowly.

CONCLUSION

The amount of bleeding and the calibre of the reconstructed bladder neck were significantly associated with AS formation after RRP. The development of a haematoma from bleeding might explain the increased likelihood of AS. The mechanism of AS formation is unrelated to the degree of urinary extravasation on cystography, providing that a urinary catheter is left indwelling until extravasation resolves.
α1‐Adrenoceptor subtypes in isolated corporal tissue from patients undergoing gender re‐assignment
Authors: EL‐GAMAL OSAMA M. , SANDHU DAVINDER P.S. , TERRY TIM , ELLIOTT RUTH A.
Published: January 2006

OBJECTIVE

To investigate the pharmacology and functionality of α1‐adrenoceptors in human corpus cavernosum, and to determine the predominant subtype.

MATERIALS AND METHODS

Cavernosal tissue specimens were obtained from the penises of 22 men (mean age 37.4 years) removed during gender re‐assignment surgery. The men had been maintained on long‐term oestrogen therapy before surgery, to aid the development of secondary feminine characteristics (oestrogen treatments were stopped 6 weeks before surgery). Corpus cavernosum strips were mounted in organ baths perfused with Krebs’ solution. A control concentration‐response curve (CRC) to phenylephrine (a nonselective α1‐agonist) was obtained. Then the tissues were incubated with the α1A antagonist, WB4101; the α1B antagonist, chloroethylclonidine; or the α1D antagonist BMY 7378 (all at 1 µm) and the CRC to phenylephrine was repeated. The concentration producing a half‐maximal response (EC50) and pKB values (logarithm of the dissociation constant, a measure of affinity) were determined.

RESULTS

WB4101 produced a parallel rightward shift of the CRC to phenylephrine, with a pKB of 7.49. BMY 7378 also produced a parallel rightward shift of the CRC to phenylephrine with a pKB of 6.45. Chloroethylclonidine had a similar effect on the phenylephrine CRC, with a pKB of 5.90.

CONCLUSION

α1‐adrenoceptors in human cavernosal tissue have a relatively low affinity for BMY 7378 and chloroethylclonidine, but are more sensitive to WB4101. This confirms that the predominant α1‐adrenoceptor subtype in human corpus cavernosum is the α1A subtype and this might help in developing more selective antagonists and agonists for managing erectile dysfunction and priapism.
Optimal Keno Strategies and the Central Limit Theorem
Authors: Johnson Roger W.
Published: January 2006

For the casino game Keno we determine optimal playing strategies. To decide such optimal strategies, both exact (hypergeometric) and approximate probability calculations are used. The approximate calculations are obtained via the Central Limit Theorem and simulation, and an important lesson about the application of the Central Limit Theorem is reinforced.
Reading and genetics: an introduction
Authors: Nation Kate
Published: January 2006

Recent years have brought about rapid advances in our understanding of how genetic factors influence reading development and reading disorder. The purpose of this special issue is to summarise what has been learned, and to highlight some of the issues and questions currently at the forefront of research. This paper sets the scene for the special issue by introducing relevant methodology and background information.
Genetic and environmental influences on early literacy
Authors: Byrne Brian , Olson Richard K. , Samuelsson Stefan , Wadsworth Sally , Corley Robin , DeFries John C. , Willcutt Erik
Published: January 2006

Prereading and early reading skills of preschool twin children in Australia, Scandinavia and the United States were explored in a genetically sensitive design (max. N=627 preschool pairs and 422 kindergarten pairs). Analyses indicated a strong genetic influence on preschool phonological awareness, rapid naming and verbal memory. Print awareness, vocabulary and grammar/morphology were subject primarily to shared environment effects. There were significant genetic and shared environment correlations among the preschool traits. Kindergarten reading, phonological awareness and rapid naming were primarily affected by genes, and spelling was equally affected by genes and shared environment. Multivariate analyses revealed genetic and environmental overlap and independence among kindergarten variables. Longitudinal analyses showed genetic continuity as well as change in phonological awareness and rapid naming across the 2 years. Relations among the preschool variables of print awareness, phonological awareness and rapid naming and kindergarten reading were also explored in longitudinal analyses. Educational implications are discussed.
Reading in able and disabled readers from around the world: same or different? An illustration from a study of reading‐related processes in a Swahili sample of siblings
Authors: Grigorenko Elena L. , Ngorosho Damaris , Jukes Matthew , Bundy Donald
Published: January 2006

Erratum. Journal of Research in Reading 29:2, 252

In this article, we discuss two characteristics of the majority of current behaviour‐ and molecular‐genetic studies of reading ability and disability, specifically, the ascertainment strategies and the populations from which samples are selected. In the context of this discussion, we present data that we collected on a sample of Swahili‐speaking siblings from Tanzania. With this sample, we (1) explore the efficiency and practicality of the single proband sibpair design and (2) provide data on the predictability of reading and spelling performance using reading‐related componential measures in a novel Swahili‐speaking sample. Specifically, we present the selection criteria, discuss the pattern of behavioural and behaviour‐genetic results obtained on the sample and compare these results with those available in the literature. We report behavioural and behaviour‐genetic correlations in this sample that are comparable with other studied samples in other languages, and discuss the similarities and differences. Thus, we demonstrate the suitability and effectiveness of the single sib ascertainment method for genetic analyses of reading ability and disability in novel samples in previously unstudied languages.
Molecular characterization and expression of four cDNAs encoding sucrose synthase from green bamboo Bambusa oldhamii
Authors: Chiu Wen‐Bin , Lin Chiou‐Hong , Chang Chun‐Ju , Hsieh Meng‐Hsun , Wang Ai‐Yu
Published: January 2006

Bamboo is distinguished by its rapid growth. To investigate sucrose metabolism in this plant, we cloned the cDNAs encoding sucrose synthase (SuS) from Bambusa oldhamii and investigated their expression in growing shoots and leaves.

Four cDNA clones, BoSus1, BoSus2, BoSus3 and BoSus4, were isolated by screening a cDNA library from etiolated bamboo shoots. Recombinant BoSuS proteins were produced in Escherichia coli and purified by immobilized metal affinity chromatography and ultrafiltration. Semi‐quantitative reverse transcriptase–polymerase chain reaction (RT‐PCR) was used to determine the abundance of the transcript of each gene.

BoSus1 and BoSus3 may be duplicate or homeologous genes, the sequences of which show high identity. Similarly, BoSus2 shows high identity with BoSus4. Kinetic analysis showed that the two BoSuS isoforms of each type had similar michaelis constant (Km) values for sucrose, but different values for UDP. The four genes were expressed in various bamboo organs but were differentially regulated. The increase in the abundance of their mRNA paralleled the growth rate of the bamboo.

The results suggest that, in bamboo, SuS is encoded by at least four genes, each with a specific role in providing substrates for the polysaccharide biosynthesis and/or energy production necessary to support the rapid growth of this species.
Consumer preference among fluid milks: low‐fat vs. high‐fat milk consumption in the United States
Authors: Robb Cliff A. , Reynolds Laura M. , Abdel‐Ghany Mohamed
Published: January 2006

The present study uses data from the Continuing Survey of Food Intakes by Individuals 1994–1996, 1998 in order to analyse milk consumption by type, specifically high‐fat milk vs. low‐fat milk. Whereas trend analysis displays an overall increase in low‐fat milk consumption over the last few decades in the United States, a number of individuals still consume high‐fat milk varieties, and overall dietary intakes have yet to achieve recommended levels. In light of recent research regarding fat intakes, it is important to understand what factors might cause consumers to purchase high‐fat options given the number of low‐fat options available in the market. Through the use of Logistic regression, key socio‐economic and demographic variables are analysed in order to determine their impacts on the probability of consuming low‐fat milk vs. high‐fat milk. The results indicate that a number of factors do influence probability of low‐fat milk consumption as compared with high‐fat milk consumption. Most notably, probability of low‐fat milk consumption appears to be positively related to age, education level, and income level. African Americans and other minorities had a lower probability of consuming low‐fat milk when compared with White people in the sample population. Also, those respondents designated as low income or living in the South were less likely to consume low‐fat milk.
Cleavage of the membrane‐bound transcription factor OASIS in response to endoplasmic reticulum stress
Authors: Murakami Tomohiko , Kondo Shinichi , Ogata Maiko , Kanemoto Soshi , Saito Atsushi , Wanaka Akio , Imaizumi Kazunori
Published: January 2006

When unfolded or misfolded proteins accumulate in the endoplasmic reticulum (ER), unfolded protein response (UPR) signals are transmitted from the ER to the nucleus and cytoplasm to facilitate protein folding. OASIS (old astrocyte specifically induced substance) is an ER stress transducer in astrocytes, a membrane‐bound transcription factor that activates genes in the ER stress response. When unfolded proteins accumulate in the ER, OASIS is cleaved at the membrane to release its cytoplasmic domain, which then enters the nucleus and activates target genes. Here, we showed that OASIS is processed by Site‐1 and ‐2 proteases (S1P and S2P), enzymes that reside at the Golgi apparatus and process activating transcription factor 6 (ATF6), in response to ER stress. We also showed that the cleavage of OASIS is triggered by its translocation to the Golgi apparatus. All deletion mutants for luminal domain of OASIS showed that proteolytic processing and translocation to the Golgi apparatus remained intact, indicating that OASIS does not have significant sequences for Golgi localization signals, different from the case of ATF6, and that there could be other systems for translocation of OASIS to the Golgi apparatus in response to ER stress.
Transcriptional disruptions in Down syndrome: a case study in the Ts1Cje mouse cerebellum during post‐natal development
Authors: Potier M.‐C. , Rivals I. , Mercier G. , Ettwiller L. , Moldrich R. X. , Laffaire J. , Personnaz L. , Rossier J. , Dauphinot L.
Published: January 2006

To understand the aetiology and the phenotypic severity of Down syndrome, we searched for transcriptional signatures in a substructure of the brain (cerebellum) during post‐natal development in a segmental trisomy 16 model, the Ts1Cje mouse. The goal of this study was to investigate the effects of trisomy on changes in gene expression across development time. The primary gene‐dosage effect on triplicated genes (∼1.5) was observed at birth [post‐natal day 0 (P0)], at P15 and P30. About 5% of the non‐triplicated genes were significantly differentially expressed between trisomic and control cerebellum, while 25% of the transcriptome was modified during post‐natal development of the cerebellum. Indeed, only 165, 171 and 115 genes were dysregulated in trisomic cerebellum at P0, P15 and P30, respectively. Surprisingly, there were only three genes dysregulated in development and in trisomic animals in a similar or opposite direction. These three genes (Dscr1, Son and Hmg14) were, quite unexpectedly, triplicated in the Ts1Cje model and should be candidate genes for understanding the aetiology of the phenotype observed in the cerebellum.
Intracellular trafficking in neurones and glia of fibroblast growth factor‐2, fibroblast growth factor receptor 1 and heparan sulphate proteoglycans in the injured adult rat cerebral cortex
Authors: Leadbeater W. E. , Gonzalez A‐M. , Logaras N. , Berry M. , Turnbull J. E. , Logan A.
Published: January 2006

The potent gliogenic and neurotrophic fibroblast growth factor (FGF)‐2 signals through a receptor complex comprising high‐affinity FGF receptor (FGFR)1 with heparan sulphate proteoglycans (HSPGs) as co‐receptors. We examined the intracellular dynamics of FGF‐2, FGFR1 and the HSPGs syndecan‐2 and ‐3, glypican‐1 and ‐2, and perlecan in neurones and glia in and around adult rat cerebral wounds. In the intact cerebral cortex, FGF‐2 and FGFR1 mRNA and protein were constitutively expressed in astrocytes and neurones respectively. FGF‐2 protein was localized exclusively to astrocyte nuclei. After injury, expression of FGF‐2 mRNA was up‐regulated only in astrocytes, whereas FGFR1 mRNA expression was increased in both glia and neurones, a disparity indicating that FGF‐2 may act as a paracrine and autocrine factor for neurones and glia respectively. FGF‐2 protein localized to both cytoplasm and nuclei of injury‐responsive neurones and glia. There was weak or no staining of HSPGs in the normal cerebral neuropil and glia nuclei, with a few immunopositive neurones. Specific HSPGs responded to injury by differentially co‐localizing with trafficked intracellular FGF‐2 and FGFR1. The spatiotemporal dynamics of FGF‐2–FGFR1–HSPG complex formation implies a role for individual HSPGs in regulating FGF‐2 storage, nuclear trafficking and cell‐specific injury responses in CNS wounds.
Protein kinase C enhances glycine‐insensitive desensitization of NMDA receptors independently of previously identified protein kinase C sites
Authors: Jackson Michael F. , Konarski Jakub Z. , Weerapura Manjula , Czerwinski Waldemar , MacDonald John F.
Published: January 2006

Protein kinase C (PKC) phosphorylates the NR1 and NR2A subunits of NMDARs at consensus sites located within their intracellular C‐terminal tails. However, the functional consequences of these biochemical events are not well understood. In HEK293 cells expressing NR1/NR2A, activation of endogenous PKC by 4β‐phorbol 12‐myristate 13‐acetate (PMA) increased NMDAR desensitization as evidenced by a reduced steady‐state current without any change in peak. The effects of PMA on NMDAR‐mediated responses were prevented by specific PKC inhibitors and were not mimicked by an inactive enantiomer of PMA. The effects of PMA were preserved despite mutagenesis of the major PKC sites on the NR1 subunit (S889A, S890A, S896A and S897A) or removal of the entire NR1 C‐terminal tail (NR1stop838). When co‐expressing NR1stop838/NR2A the effects of PMA could only be observed with agonist concentrations sufficient to induce glycine‐insensitive desensitization. Moreover, the effects of PMA were observed in receptors composed of NR1/NR2A and NR1/NR2B, but not NR1/NR2C, a subunit combination in which desensitization is absent. The NR2 subunit dependence suggested that the actions of PMA might require specific PKC sites previously identified within NR2A. However, a C‐terminal truncated form of NR2A (NR2Astop905) remained responsive to PMA. We conclude that activation of PKC increases NMDAR glycine‐insensitive desensitization independently of previously identified sites located within the NR1 C‐terminus and distal segment of the NR2A C‐terminus.
Fellows ’ Forum: Hip Fractures in End‐Stage Renal Disease Patients: IncidenceRisk Factorsand Prevention
Authors: Leinau Lisa , Perazella Mark A.
Published: January 2006

Hip fractures are an important problem for end‐stage renal disease (ESRD) patients treated with dialysis. The incidence of hip fractures in the dialysis population is approximately four times that of the general population. Even more concerning is the associated 1 year mortalitywhich is twice that of other dialysis patients. Management of this problem is complicated by the heterogeneous nature of renal osteodystrophy and the inadequate methods of diagnosis currently available. Fall prevention has been shown to reduce the incidence of hip fracture and associated decline in functional ability in the general population. Because falls occur frequently in the dialysis populationsimple fall prevention may be one important way of protecting dialysis patients from the morbidity and mortality of hip fracture.
Quality Assessment of DNA Sequence Data: Autopsy of A Mis‐Sequenced mtDNA Population Sample
Authors: Bandelt H.‐J. , Kivisild T.
Published: January 2006

Published DNA data sets constitute a body of sequencing results resting in silico that are supposed to reflect the variation of (once) living cells. In cases where the DNA variation reported is suspected to be fraught with artefacts, an autopsy of the full body of data is needed to clarify the amount and causes of mis‐sequencing. In this paper we elaborate on strategies that allow a clear‐cut identification of the problems in severely flawed mtDNA data. This approach is applied, by way of example, to a data set of HVS‐I sequences from the Caucasus, published by Nasidze & Stoneking in 2001. These data bear numerous ambiguous nucleotide positions and suffer from an even higher number of phantom mutations, indicating that severe biochemical problems adversely influenced those sequencing results at the time. Furthermore, systematic omission of sequences with a long C‐stretch (incurred by a transition at position 16189) must have severely biased the data set. Since no complete correction of these data has appeared to date, this example of mis‐sequencing necessitates circumstantial evidence that is bullet‐proof.
Resource partitioning and exploitative competition in stem‐galling midges mediated by the host plant
Authors: Dorchin Netta
Published: January 2006

Izeniola obesula Dorchin and Stefaniola defoliata Dorchin (Diptera, Cecidomyiidae) are two cecidomyiid species inducing multichambered galls in young shoots of the salt marsh plant, Suaeda monoica Gmelin (Chenopodiaceae). The purpose of this work was to study the relationship between the two species, which co‐occur in time and space, and may therefore potentially compete for plant resources.

Characterization of the resources available to ovipositing females revealed that shoots in apical positions are more vigorous than shoots in basal positions, but that the two species of gall midges react to this variability of resources in different ways, as reflected by the patterns of gall distribution. Izeniola obesula galls were primarily induced in the younger, more rapidly growing shoots, whereas those of S. defoliata were predominantly induced in older, less vigorous shoots. Nevertheless, despite the general partitioning of resources, a certain amount of niche overlap was found, resulting in the occasional induction of an S. defoliata gall proximal to that of I. obesula in the same shoot. Co‐occurrence of the two types of galls in time and space did not have apparent effect on S. defoliata galls, but did have a strong adverse impact on young I. obesula galls, 60% of which were killed without producing adult midges, and the remaining 40% produced a much smaller number of adults. These effects are attributed to asymmetric interspecific competition that is mediated by the plant, resulting from the difference in stem tissues utilized by the larvae of the two species. It is concluded that preponderance of vacant niches, low densities of galls, and small niche overlap between the species do not preclude the occurrence of interspecific exploitative competition in this system, although its role in shaping the populations of the species is limited.
Field‐cage experiments on host fidelity in a pair of sympatric phytophagous ladybird beetles
Authors: Hirai Yoshiyuki , Kobayashi Hideshi , Koizumi Tatsuya , Katakura Haruo
Published: January 2006

Using field cages, we tested the hypothesis that two phytophagous ladybird beetles, Henosepilachna niponica (Lewis) and Henosepilachna yasutomii Katakura (Coleoptera: Coccinellidae: Epilachninae), are reproductively isolated from each other by their host fidelity alone. We planted host plants of the two species [the thistle Cirsium alpicola Nakai (Asteraceae) for H. niponica and the blue cohosh, Caulophyllum robustum Maxim. (Berberidaceae), for H. yasutomii] in 7 × 7 m cages (BT cages), and planted the two host plants and the beetles’ common food plant, the Japanese nightshade, Solanum japonense Nakai (Solanaceae), in other cages (BJT cages). We then released overwintered reproducing beetles into these cages and recorded their dispersal, the distribution of egg masses, and the incidence of copulations. In BT cages, the beetles moved almost exclusively between their own host plants, and all females laid eggs exclusively on their own host plants. In BJT cages, the beetles moved between their own host plants and the Japanese nightshade, resulting in occasional interspecific mating on the same nightshade plant. Females of both species laid eggs on their own host plants as well as on the Japanese nightshade. These results indicate that host fidelity functions as a strong barrier against gene flow between H. niponica and H. yasutomii. However, this barrier can easily be broken down if a third plant species bridges the beetle populations.
Should aphidophagous ladybirds be reluctant to lay eggs in the presence of unsuitable prey?
Authors: Fréchette Bruno , Dixon Anthony F.G. , Alauzet Claude , Boughenou Naïma , Hemptinne Jean‐Louis
Published: January 2006

The quality of different species of aphids as food for aphidiphagous ladybird beetles varies greatly. The optimal oviposition theory predicts that a female should lay eggs preferentially in patches of suitable prey and should be reluctant to oviposit in patches of less suitable prey. A no‐choice experiment was used to test whether aphids (Homoptera: Aphididae) of different suitability influence the oviposition behaviour of the two‐spot ladybird beetle, Adalia bipunctata (L.) (Coleoptera: Coccinellidae). The results indicate that A. bipunctata females are not more reluctant to lay eggs in the presence of moderately suitable compared to highly suitable aphids. However, females laid fewer eggs in the presence of toxic aphids.
Bt maize pollen exposure and impact on the garden spider, Araneus diadematus
Authors: Ludy C. , Lang A.
Published: January 2006

Concerns have been raised that Bt maize pollen may have adverse effects on non‐target organisms; consequently, there is a general call for Bt maize risk assessment evaluating lethal and sublethal side effects. Spiders play an important economic and ecological role as pest predators in various crops, including maize. Web‐building spiders, especially, may be exposed to the Cry1Ab toxin of Bt maize by the ingestion of pollen via ‘recycling’ of pollen‐dusted webs and intentional pollen feeding. In this study, the potential Bt maize pollen exposure of orb‐web spiders was quantified in maize fields and adjacent field margins, and laboratory experiments were conducted to evaluate the possible effects of Bt maize pollen consumption on juvenile garden spiders, Araneus diadematus (Clerck) (Araneae: Araneidae). In maize fields and neighbouring field margins, web‐building spiders were exposed to high amounts of Bt maize pollen. However, a laboratory bioassay showed no effects of Bt maize pollen on weight increase, survival, moult frequency, reaction time, and various web variables of A. diadematus. A pyrethroid insecticide (Baythroid) application affected weight increase, survival, and reaction time of spiders negatively. In conclusion, the insecticide tested showed adverse effects on the garden spider, whereas the consumption of Bt maize pollen did not. This study is the first one on Bt maize effects on orb‐web spiders, and additional research is recommended in order to account for further spider species, relative fitness parameters, prey‐mediated effects, and possible long‐term chronic consequences of Bt exposure.
Seasonal variation in seed predation by adult carabid beetles
Authors: Honek Alois , Saska Pavel , Martinkova Zdenka
Published: January 2006

In many agro‐ecosystems of the temperate region, granivorous ground beetles (Coleoptera: Carabidae) are the most important invertebrate predators of seeds after dispersal. The consumption of a particular species of seed differs among carabid species, but seasonal variation in consumption has not yet been studied. Seasonal differences in the quantity of seed consumed by the carabidsHarpalus affinis(Schrank) andHarpalus distinguendus(Duftschmid) were studied in a cafeteria experiment. Adults were collected on five dates between April and November and provided with seeds of 28 species of dicotyledonous herbaceous plants. Proportions eaten of the seeds offered (preferences) were nearly identical in both carabid species. Overall seed consumption increased from early spring until late June, then gradually decreased towards autumn. Despite this variation, the preferences on particular dates were essentially similar. Seasonal variation in carabid physiology and feeding experience thus influenced overall seed consumption, but not their preferences for particular seed species.
Presenilin‐1‐mediated Retention of APP Derivatives in Early Biosynthetic Compartments
Authors: Réchards Marloes , Xia Weiming , Oorschot Viola , van Dijk Suzanne , Annaert Willem , Selkoe Dennis J. , Klumperman Judith
Published: January 2006

Processing of the amyloid precursor protein (APP) leads to the production of amyloid‐β (Aβ), the major component of extracellular plaques in the brains of Alzheimer's disease (AD) patients. Presenilin‐1 (PS‐1) plays a key role in the final step of Aβ formation, the γ‐secretase cleavage. Previously, we showed that PS‐1 is retained in pre‐Golgi compartments by incorporation into COPI‐coated membranes of the vesicular tubular clusters (VTCs) between endoplasmic reticulum (ER) and Golgi complex. Here, we show that PS‐1 also mediates the retention of the β‐cleavage‐derived APP‐C‐terminal fragment (CTFβ) and/or Aβ in pre‐Golgi membranes. Overexpression of PS‐1 increased the percentage of CTFβ and/or Aβ in VTCs as well as their distribution to COPI‐coated VTC membranes. By contrast, overexpression of the dominant‐negative aspartate mutant PS‐1D257A or PS‐knockout decreased incorporation of these APP derivatives into COPI‐coated membranes. Sorting of APP derivatives to COPI‐coated VTC membranes was not depending on the APP cytosolic tail. In post‐Golgi compartments, PS‐1 expression enhanced the association of full‐length APP/APPs with endosomal compartments at the expense of plasma membrane‐bound APP. We conclude that PS‐1, in addition to its role in γ‐secretase cleavage, is also required for the subcellular routing of APP and its derivatives. Malfunctioning of PS‐1 in this role may have important consequences for the progress of AD.
Post‐Apartheid Disgrace: Guilty Masculinities in White South African Writing
Authors: Horrell Georgie
Published: January 2006

In the aftermath of the Truth and Reconciliation Commission in South Africa J. M. Coetzee writes of the ‘system’ of guilt and shame, debt and retribution which operates throughout society. He and writers like André Brink, Michiel Heyns and Troy Blacklaws tell stories which traverse and explore the paths tracked by society's quest for healing and restitution. This article considers a selection of transitional, contemporary white novels in South Africa in order to gesture towards discourses of both particular and global postcolonial significance, referring particularly to gender and representations of white masculinity in the post‐apartheid era.