bluuebunny/crossref_metadata_2025 huggingface dataset:
Cellulosomes: microbial nanomachines that display plasticity in quaternary structure
Authors: Gilbert Harry J.
Published: March 2007

The assembly of proteins that display complementary activities into supramolecular intra‐ and extracellular complexes is central to cellular function. One such nanomachine of considerable biological and industrial significance is the plant cell wall degrading apparatus of anaerobic bacteria termed the cellulosome. The Clostridium thermocellum cellulosome assembles through the interaction of a type I dockerin module in the catalytic entities with one of several type I cohesin modules in the non‐catalytic scaffolding protein. Recent structural studies have provided the molecular details of how dockerin–cohesin interactions mediate both cellulosome assembly and the retention of the protein complex on the bacterial cell surface. The type I dockerin, which displays near‐perfect sequence and structural symmetry, interacts with its cohesin partner through a dual binding mode in which either the N‐ or C‐terminal helix dominate heterodimer formation. The biological significance of this dual binding mode is discussed with respect to the plasticity of the orientation of the catalytic subunits within this supramolecular assembly. The flexibility in the quaternary structure of the cellulosome may reflect the challenges presented by the degradation of a heterogenous recalcitrant insoluble substrate by an intricate macromolecular complex, in which the essential synergy between the catalytic subunits is a key feature of cellulosome function.
Molecular analysis of resistance mechanisms to Orobanche cumana in sunflower
Authors: Letousey P. , De Zélicourt A. , Vieira Dos Santos C. , Thoiron S. , Monteau F. , Simier P. , Thalouarn P. , Delavault P.
Published: March 2007

Resistance to the dicotyledenous parasite Orobanche cumana in sunflower is characterized by a low number of parasitic attachments and a confinement of the parasite in host tissues leading to its necrosis. To help understand what determines such resistance mechanisms, molecular, biochemical and histological approaches were employed before (early response) and after (late response) attachment of the broomrape parasite to susceptible (2603) and resistant (LR1) sunflower genotypes. The expression patterns of 11 defence‐related genes known to be involved in different metabolic pathways (phenylpropanoids, jasmonate, ethylene) and/or in resistance mechanisms against microorganisms were investigated. RT‐PCR and cDNA blot experiments revealed that the resistant genotype exhibited a stronger overall defence response against O. cumana than the susceptible one, involving marker genes of the jasmonate (JA) and salicylic acid (SA) pathways. Among them, the SA‐responsive gene, def. (defensin), appeared to be characteristic of LR1 sunflower resistance. However, no JA accumulation and similar SA contents (250–300 ng g−1 FW) were measured by GC/MS in both genotypes, parasitized or not. In addition, three cDNAs, isolated by a suppression‐subtractive hybridization, were shown to be strongly induced only in the resistant genotype 8 days post‐inoculation, when the first O. cumana attachments occurred. These genes, putatively encoding a methionine synthase, a glutathione S‐transferase and a quinone oxidoreductase, might be involved in detoxification of reactive oxygen species, suggesting the occurrence of an oxidative burst during the incompatible interaction. Finally, host cell‐wall modifications leading to parasite‐confinement were correlated with more intense callose depositions in the resistant genotype, concomitant with over‐expression of the callose synthase cDNA HaGSL1.
Co‐operational PCR coupled with dot blot hybridization for detection and 16SrX grouping of phytoplasmas
Authors: Bertolini E. , Torres E. , Olmos A. , Martín M. P. , Bertaccini A. , Cambra M.
Published: March 2007

A protocol based on Co‐operational PCR has been successfully applied to the detection of phytoplasmas. A triprimer reaction coupled with hybridization using general and specific probes permitted detection of ‘Candidatus Phytoplasma mali’, ‘Ca. Phytoplasma prunorum’ and ‘Ca. Phytoplasma pyri’, and their identification as members of 16S ribosomal quarantine group X. The sensitivity of this method was at least one hundred times greater than conventional PCR and similar to that achieved by nested PCR and real‐time PCR. The method was validated by testing field samples collected from Malus, Prunus and Pyrus spp. and Olea europaea and compared with seven phytoplasmas maintained in Catharanthus roseus.
Analysis of resistance to Xylella fastidiosa within a hybrid population of Pera sweet orange × Murcott tangor
Authors: Coletta‐Filho H. D. , Pereira E. O. , Souza A. A. , Takita M. A. , Cristofani‐Yale M. , Machado M. A.
Published: March 2007

Resistance to Xylella fastidiosa was evaluated within a population of 20 interspecific hybrids of Pera sweet orange and Murcott tangor under greenhouse conditions. Efficiency of inoculation, multiplication of bacteria within the plants, xylem vessel morphology, and symptom expression were analysed. The rate of infection ranged from 40 to 100% (average 70%) for all genotypes analysed. Xylella fastidiosa populations ranged from log 0·59 to log 2·13 cells mg−1 tissue for the resistant hybrids. These values were significantly different (P = 0·05) from those obtained for the tolerant (no symptoms but bacteria recovered) or susceptible (symptoms and bacteria recovered) hybrids (log 3·02 to log 4·06 cells mg−1). Xylella fastidiosa was recovered from all hybrids (log 2·31 to 5·03 CFU mg−1 tissue) except the resistant ones. The first foliar symptoms appeared at least 90 days post‐inoculation, the time varying according to genotype. No correlation between xylem vessel morphology and disease expression was observed, indicating that the resistance was the result of a genetic response of the host. According to this hypothesis, a high broad‐based heritability index for resistance was obtained (0·96) at 210 days from X. fastidiosa inoculations, using bacterial quantification by real‐time PCR, which indicated that the influence of the number of bacteria was the result of genetic rather than environmental variations.
Acitretin‐induced subungual hemorrhage
Authors: Aydogan Kenan , Karadogan Serap Koran , Tunali Sukran
Published: March 2007

A 20‐year‐old woman with a 2‐year history of histologically confirmed palmoplantar keratoderma due to psoriasis, resistant to several topical agents, was admitted to the Department of Dermatology, Uludag University, Bursa, Turkey. Therapy with oral acitretin (0.5 mg/kg/day, 35 mg/day) was initiated. A month after starting acitretin treatment, she noted slight reddening of the second left fingernail. Clinical examination revealed red–brown discoloration of the second fingernail associated with subungual hemorrhage involving the proximal nail bed (lunula region) (Fig. 1). The nail change was asymptomatic. The patient complained only of discoloration underneath the nail plate. No abnormalities were detected on the skin, mucous membranes, or toenails/other fingernails. The patient denied exposure to microtrauma or any other drugs. The erythrocyte sedimentation rate, full blood cell count, electrolytes, renal and hepatic tests, and serum lipids were normal. Coagulation tests, including blood clotting time, international normalized ratio, activated partial thromboplastin time, thrombin time, platelet number, and function tests, were within normal levels.

Acitretin‐induced subungual hemorrhage involving the proximal portion (lunula region) of the second left fingernail bed

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Treatment with acitretin was discontinued, and the nail change resolved completely after 3 weeks. A similar episode of subungual hemorrhage recurred, however, within 48 h after re‐challenge with a lower dose of acitretin (25 mg/day). The drug was definitively stopped and the eruption faded again within a week. An objective causality assessment suggests that subungual hemorrhage was probably related to acitretin in this patient.
Sex‐specific ecomorphological variation and the evolution of sexual dimorphism in dwarf chameleons (Bradypodion spp.)
Authors: STUART‐FOX D. , MOUSSALLI A.
Published: March 2007

Natural selection can influence the evolution of sexual dimorphism through selection for sex‐specific ecomorphological adaptations. The role of natural selection in the evolution of sexual dimorphism, however, has received much less attention than that of sexual selection. We examined the relationship between habitat structure and both male and female morphology, and sexual dimorphism in size and shape, across 21 populations of dwarf chameleon (genus Bradypodion). Morphological variation in dwarf chameleons was strongly associated with quantitative, multivariate aspects of habitat structure and, in most cases, relationships were congruent between the sexes. However, we also found consistent relationships between habitat and sexual dimorphism. These resulted from both differences in magnitude of ecomorphological relationships that were otherwise congruent between the sexes, as well as in sex‐specific ecomorphological adaptations. Our study provides evidence that natural selection plays an important role in the evolution of sexual dimorphism.
Genotypic selection in Daphnia populations consisting of inbred sibships
Authors: HAAG C. R. , EBERT D.
Published: March 2007

The genetic basis of fitness reduction associated with inbreeding is still poorly understood. Here we use associations between allozyme genotypes and fitness to investigate the genetic basis of inbreeding depression in experimental outdoor populations of the water flea, Daphnia magna. In Daphnia, a phase of clonal reproduction follows hatching from sexually produced resting eggs, and changes in genotype frequencies during the clonal phase can be used to estimate fitness. Our experiment resembles natural colonization of ponds in that single clones colonize an empty pool, expand asexually and produce sexual offspring by selfing (sisters mate with their clonal brothers). These offspring diapause and form populations consisting of selfed sibships in the following spring. In 12 of 13 experimental populations, genotypes of selfed hatchlings after diapause conformed to Mendelian expectations. During the subsequent ca. 10 asexual generations, however, genotype frequencies changed significantly at 19 of 27 single loci studied within populations, mostly in favour of heterozygotes, with heterozygosity at multiple loci affecting the change in genotype frequency multiplicatively. Because variance in heterozygosity among siblings at a given marker reflects only heterozygosity in the chromosomal region around this marker, our results suggest that selection at fitness‐associated loci in the chromosomal regions near the markers were responsible for these changes. The genotype frequency changes were more consistent with selection acting on linked loci than on the allozymes themselves. Taken together, the evidence for abundant selection in the chromosomal regions of the markers and the fact that changes in genotype frequencies became apparent only after several generations of clonal selection, point to a genetic load consisting of many alleles of small or intermediate effects, which is consistent with the strong genetic differentiation and repeated genetic bottlenecks in the metapopulation from which the animals for this study were obtained.
Effects of photoperiod and temperature on the development and diapause of the bark beetle Ips typographus
Authors: Doležal P. , Sehnal F.
Published: March 2007

Abstract:  Diapause was induced in a Central European population of Ips typographus grown at 20°C when the day length decreased below 16 h [50% diapause incidence occurred in the 14.7:9.3 h L:D (light:dark) regime]. The non‐diapausing adults fed on days 2–6 and 10–14 after the ecdysis and swarmed after the second feeding bout with chorionated eggs in the ovaries and sperm in the spermiducts. Neither gonads nor the flight muscles matured and no swarming occurred in the diapausing adults. The development from egg to adult took about 34 days in both 18:6 h (no diapause) and 12:12 h L:D (diapause) regimes, but it was extended by up to 30% without diapause induction when only larvae or pupae were exposed to L:D 12:12 h. Diapause was induced in insects reared at L:D 12:12 h through the last larval and the pupal instars and/or in the adult stage. Temperature ≥ 23°C prevented diapause induction at L:D 12:12 h but diapause occurred at L:D 14:10 h associated with 26:6°C thermoperiod. The effect of thermoperiods on the developmental rate requires further research. Exposure of the non‐diapausing adults to 5°C for several days blocked feeding and evoked a diapause‐like state, whereas diapausing adults fed and their gonads slowly developed at this temperature. Diapausing adults exposed in forest to low night temperatures and transferred in October to 20°C readily reproduced at 18:6, but not 12:12 h L:D photoperiods. After 2‐months at 5°C and darkness, they became insensitive to the photoperiod, matured and most of them also swarmed at 20°C in the 12:12 h L:D regime. In a Scandinavian population, diapause occurred at 18:6 h L:D and was terminated either by exposure to 5°C or by very long photoperiod (L:D 20:4 h) combined with high temperature (23°C).
Nematophagous Fungi Associated with Root Galls of Rice Caused by Meloidogyne graminicola and its Control by Arthrobotrys dactyloides and Dactylaria brochopaga
Authors: Singh K. P. , Jaiswal R. K. , Kumar N. , Kumar D.
Published: March 2007

Root galls of rice caused by Meloidogyne graminicola were examined for natural colonization by nematophagous fungi from four fields with different nematode infestations. Old galls from severely infested fields had a higher frequency of Monacrosporium eudermatum and Stylopaga hadra than young galls. The frequency of Arthrobotrys oligospora, Arthrobotrys dactyloides, Dactylaria brochopaga and Monacrosporium gephyropagum was lower. A greater proportion (%) of root galls were colonized by nematophagous fungi in those fields in which rice roots had a greater root gall index. This indicated that disease severity supported the colonization of galls by nematophagous fungi. In vitro predacity tests of four fungi showed that A. dactyloides was most effective in capturing and killing J2 of Mel. graminicola followed by D. brochopaga and Mon. eudermatum. Application of inocula of A. dactyloides and D. brochopaga in soil infested with Mel. graminicola, respectively, reduced the number of root galls by 86% and of females by 94%, and eggs and juveniles by 94%. The application of these fungi to soil increased plant growth: shoot length by 42.7% and 39.8%, root length by 45.5% and 48.9%, fresh weight of shoot by 59.9% and 56.7% and fresh weight of root by 20.3% and 25.1%, respectively, compared to these parameters for plants grown in nematode‐infested soil.
Molecular Characterization and Potential Insect Vector of a Phytoplasma Associated with Garden Beet Witches’ Broom in Yazd, Iran
Authors: Mirzaie A. , Esmailzadeh‐Hosseini S. A. , Jafari‐Nodoshan A. , Rahimian H.
Published: March 2007

In 2002, garden beet witches’ broom (GBWB) phytoplasma was detected for the first time in garden beet plants (Beta vulgaris L. ssp. esculenta) in Yazd, Iran. Nested polymerase chain reaction (PCR) and restriction fragment length polymorphic (RFLP) analysis of PCR‐amplified phytoplasma 16S rDNA were employed for the detection and identification of the phytoplasma associated with garden beet. A phytoplasma belonging to subgroup 16SrII‐E, in the peanut witches’ broom group (16SrII), was detected in infected plants. Asymptomatic plant samples and the negative control yielded no amplification. The result of analysis of the nucleotide sequence of a 1428 bp fragment of 16S rDNA gene from GBWB phytoplasma (GenBank accession number DQ302722) was basically consistent with the classification based on RFLP analysis, in which GBWB phytoplasma clustered with phytoplasmas of the 16SrII‐E subgroup. A search for a natural phytoplasma vector was conducted in Yazd in 2004, in an area where garden beet crops had been affected since 2002. The associated phytoplasma was detected in one leafhopper species, Orosius albicinctus, commonly present in this region. The leafhopper O. albicinctus was used in transmission tests to determine its vector status for the phytoplasma associated with GBWB. Two of eight plants that had been fed on by O. albicinctus, showed mild symptoms of GBWB including stunting and reddening of midveins. A phytoplasma was detected in the two symptomatic test plants by PCR using universal primers and it was identified by RFLP as the GBWB phytoplasma. This finding suggests O. albicinctus is a vector of the GBWB phytoplasma.
A Comparison of Three Experimental Designs for the Field Assessment of Resistance to Rice Blast Disease (Pyricularia oryzae)
Authors: Katsantonis D. , Koutroubas S. D. , Ntanos D. A. , Lupotto E.
Published: March 2007

The reliability and the effectiveness of three field experimental designs for the assessment of varietal resistance to Pyricularia oryzae was studied for 2 years. Plants were arranged in the field using two sets of three designs: randomized compete block (RCB), adjacent control (AC) and honeycomb (HC). In the first set, plants were inoculated with the fungus and in the second one, plants were naturally infected. Four varieties were used, Maratelli (susceptible control), Roxani, Selenio and Senia (main varieties). Disease progress was recorded as leaf and neck blast. The number of plants of the main varieties required in each design was higher for RCB (90) and lower for AC and HC (30 and 32, respectively). Results showed that disease severity was significantly different in the varieties studied and it was consistent and not affected by the plant arrangement in the field. All experimental designs were reliable and effective for the assessment of leaf and neck blast under inoculation or natural infection. AC and HC designs had the advantage of requiring fewer plants over RCB one. This could be important in cases where seed availability is a limiting factor.
Detection, Identification and Molecular Characterization of a Phytoplasma Associated with Arabian Jasmine (Jasminum sambac L.) Witches’ Broom in Oman
Authors: Al‐Zadjali A. D. , Natsuaki T. , Okuda S.
Published: March 2007

Arabian jasmine (Jasminum sambac L.) plants showing witches’ broom (WB) symptoms were found in two regions in the Sultanate of Oman. Polymerase chain reaction (PCR) amplification of the 16S rRNA gene and the 16S–23S spacer region utilizing phytoplasma‐specific universal and designed primer pairs, and transmission electron microscopy of phytoplasma‐like structures in phloem elements confirmed phytoplasma infection in the symptomatic plants. PCR products primed with the P1/P7 primer pair were 1804 bp for jasmine witches’ broom (JasWB) and 1805 bp for alfalfa (Medicago sativa L.) witches’ broom (AlfWB). Actual and putative restriction fragment length polymorphic analysis indicated that jasmine and AlfWB phytoplasmas were molecularly indistinguishable from each other and closely related to papaya yellow crinkle (PYC), as well as being distinct from lime WB (LWB) and Omani alfalfa WB (OmAlfWB) phytoplasmas. A sequence homology search of JasWB and AlfWB showed 99.8% similarity with PYC from New Zealand and 99.6% similarity with each other (JasWB/AlfWB). The jasmine and AlfWB phytoplasmas were also shown to be related to the peanut WB group (16SrII) of 16S rRNA groups based on a phylogenetic tree generated from phytoplasma strains primed with the P1/P7 primer pair and representing the 15 phytoplasma groups.
Cytopathology, Mode of Aphid Transmission and Search for the Casual Agent of Cotton Bunchy Top Disease
Authors: Ali A. , Reddall A. , Roberts J. , Wilson L. J. , Rezaian M. A.
Published: March 2007

The cytopathological effects of cotton bunchy top (CBT) disease and its mode of transmission by Aphis gossypii Glover (cotton aphid), were studied. CBT infection affected the leaf epidermal layer producing a loose, ruptured and rough surface morphology with many stomata closed and misshapen. Roots of CBT‐infected plants showed reduced growth, small knots and a dark brown appearance. A single aphid per plant was capable of transmitting CBT at 5%, whereas three aphids per plant transmitted CBT to 50% of the cotton seedlings and 20 aphids per plant transmitted the disease agent to 80% of the cotton seedlings. Aphis gossypii acquired CBT after a minimum acquisition access period of 5 min and transmitted the agent after a minimum inoculation access period of 1 h. Both alate and apterous aphids and nymph instars 2, 3 and 4 of A. gossypii transmitted CBT. This preliminary data suggest that A. gossypii transmits CBT in a semi‐persistent manner. Myzus persicae Sulz (green peach aphid) was unable to transmit CBT. A comprehensive attempt to isolate the CBT agent, using a range of virological techniques including double‐stranded RNA extraction, two‐dimensional gel electrophoresis for viroid, circular DNA test, nanovirus polymerase chain reaction (PCR), luteovirus PCR and enzyme‐linked immunosorbent assay, phytoplasma test, nucleoprotein purification and electron microscopy, was unsuccessful, raising the possibility that CBT may be caused by a unique new pathogen.
Effects of Light Quality on Induction of Tryptamine‐mediated Resistance in Lesion Mimic Mutant of Rice Infected with Magnaporthe grisea
Authors: Ueno M. , Imaoka A. , Kihara J. , Arase S.
Published: March 2007

The effective wavelength of light on Sekiguchi lesion formation, tryptamine accumulation, enzyme activities and hydrogen peroxide (H2O2) generation involved in light‐induced resistance of rice (cv. Sekiguchi‐asahi) infected with Magnaporthe grisea was determined by using band‐pass filters (BPF). When the M. grisea‐inoculated leaves were irradiated by BPF‐filtered lights from daylight fluorescent lamps, Sekiguchi lesion development was enhanced by increasing the wavelength of visible light. The longer the radiation wavelength, the greater the tryptamine accumulation, the tryptophan decarboxylase and monoamine oxidase activities, and the H2O2 generation. By contrast, the longer the radiation wavelength of radiation, the greater the inhibition of catalase (CAT) activity. Among the visible lights, red light was the most effective for tryptamine pathway activation and CAT inhibition involved in light‐induced resistance.
What older people do: Time use and exploring the link between role participation and life satisfaction in people aged 65 years and over
Authors: McKenna Kryss , Broome Kieran , Liddle Jacki
Published: March 2007

Objectives:  Data on time use and role participation can provide rich information that can help occupational therapists better understand older people's lives. This study aimed to (i) describe the time use and role participation of community‐dwelling people aged 65 years and older, (ii) analyse whether time use and role participation changed with increasing age, and (iii) determine if there is a link between maintenance of role participation and life satisfaction in older age.

Methods:  Using a cross‐sectional design, interviews including the Activity Configuration, Role Checklist and Life Satisfaction Index‐Z were used to collect data on 195 participants (mean age 75 years, 58.5% female).

Results:  Participants spent most of their time on sleep (8.4 h/day), solitary leisure (4.5 h/day), instrumental activities of daily living (3.1 h/day), social leisure (2.7 h/day) and basic activities of daily living (2.6 h/day). The most common roles were friend (96.4%), family member (95.4%) and home maintainer (87.2%). Participants aged 75 years and older spent significantly more time on solitary leisure and less time on paid work and transport compared to those aged 65–74 years. Role maintenance was significantly related to greater life satisfaction in participants aged 75–84 years.

Conclusion:  Older people's occupations and roles are diverse, and increasing age does not appear to reduce occupational or role engagement. The value of roles is not always reflected in the amount of time devoted to them and facilitating continued participation in valued roles may be important for older people's life satisfaction.
A 22 month study of patient complaints at a National Health Service hospital
Authors: Siyambalapitiya Sajith , Caunt Julie , Harrison Natalie , White Lesley , Weremczuk Denise , Fernando Devaka JS
Published: March 2007

Patient complaints are an important source of information for service improvements. We audited patient complaints made about medical care in a National Health Service District general hospital over a 22 month period. Complaints were about medical care, nursing care, attitudes of staff, poor communication, clinical delay (9%) and hospital environment. The complaints department closed 66% complaints within 20 days. The majority of the complaints were directly related to clinical care, poor communication, attitudes of staff and nursing care. However, 99% of patients were satisfied with an explanation and an apology indicating that almost all have been due to a lack of good communication than due to real deficiencies in the clinical care. The hospital management has investigated the majority of cases within 20 days and has made several policy changes after the investigations.
Witnessing tragedy: Nurses' perceptions of caring for patients with cancer
Authors: Kendall Sharon
Published: March 2007

This paper details one of the findings of a large phenomenological study into the effects of nurse–patient encounters on clinical learning and practice. Every nurse faces the challenge of caring for a patient with cancer at some point in his or her nursing career. The participants, 392 nurses, were asked to discuss a care episode from their practice and the impact this encounter had on clinical learning and practice. The data collection method was by way of a written narrative/clinical exemplar. Meaning units and themes were identified using the Nvivo computer program. The procedural method of Giorgi was followed in all phases of analysis. The participants provided a detached description of the patients' diagnoses but tended to become emotive when discussing the cancer treatment experience. Nurses detailed care episodes with insight and understanding of the consequences of cancer for the patient. Nurses used powerful language to illustrate the enormity of the cancer experience for the patient and family. Although the nurses recognized the emotional impact themselves, they attempted to understate it. Participants spoke of their frustration and their sadness when describing the nurse–patient encounters. The life‐threatening potential of cancer for the patient and the perception of potential or actual suffering do impact on nurses, their learning and their clinical practice. This is particularly evident when the cancer experience for the patient is not predictable. Participants clearly felt the influence of patients' cancer experience, personally and professionally. Participants detailed learning from the encounters and reflected with great insight on themselves and their practice. Identifying the learning potential of nurse–patient encounters can contribute to change in clinical practice.
Professional socialization: The key to survival as a newly qualified nurse
Authors: Mooney Mary
Published: March 2007

The impact and prevalence of professional socialization in nursing has been written about extensively. Despite the many positive developments that have taken place in nursing within the past decade, the role of professional socialization remains heavily weighted and is of particular significance to those nurses who are newly qualified. The account given by newly registered nurses in this study demonstrates that their ability and willingness to become professionally socialized determines their ease of survival at clinical level. Twelve newly qualified Irish nurses, from two separate cohorts, were interviewed to ascertain their perceptions of becoming newly qualified nurses. A grounded theory approach was used and data were analysed using thematic analysis. A category that emerged was linked very strongly with professional socialization. The respondents did not refer to professional socialization per se, but through the coding process this emerged as the linchpin of the discussion.
Do Australian small mammals respond to native and introduced predator odours?
Authors: RUSSELL BENJAMIN G. , BANKS PETER B.
Published: March 2007

Abstract  Coevolution is thought to have led to many small mammal species avoiding the scent marks of their main mammalian predators, as they provide a reliable cue to predation risk. Most support for this hypothesis comes from northern hemisphere predator/prey systems, however, it is unclear whether this avoidance of predator faecal odour occurs in Australia's mammalian fauna, which has evolved in relative isolation from the rest of the world, and is dominated by marsupials rather than placentals. We tested this theory for an Australian system with marsupial and placental predators and prey, that share a long‐term (>1 million years) or short‐term (<150 years) exposure to each other. The predators were the native marsupial tiger quoll Dasyurus maculatus and the introduced placental red fox Vulpes vulpes. The potential prey were three native rodent species, the bush rat Rattus fuscipes, the swamp rat Rattus lutreolus, the eastern chestnut mouse Pseudomys gracilicaudatus, and the marsupial brown antechinus Antechinus stuartii. Small mammals were captured in Elliott traps with 1/3 of traps treated with fox faeces, 1/3 treated with quoll faeces and the remainder left untreated. The native rodent species all showed avoidance of both tiger quoll and red fox odours whereas the marsupial antechinus showed no responses to either odour. Either predator odour avoidance has not evolved in this marsupial or their reaction to predator odours may be exhibited in ways which are not recognizable through trapping. The avoidance by the rodents of fox odour as well as quoll odour indicates this response may either be due to common components in fox and quoll odour, or it may be a recently evolved response.
Fine‐scale microhabitat selection for dense vegetation in a heathland rodent, Rattus lutreolus: Insights from intraspecific and temporal patterns
Authors: KEARNEY NICOLE , HANDASYDE KATHRINE , WARD SIMON , KEARNEY MICHAEL
Published: March 2007

Abstract  Vegetation is a dynamic habitat component and successional changes in vegetation structure can lead to concomitant changes in the communities of animals living in a particular area. Heathland rodents are a classic example, with vegetation at different ages post fire being dominated by different species. While broad associations are often demonstrated between the distribution and abundance of species and vegetation structure, the causal relationships are poorly understood. Studies of temporal and sex‐ or age‐specific patterns can provide strong insights into the processes underling patterns of habitat selection. In an attempt to better understand the mechanistic links between rodent successional patterns and vegetation structure in heathlands, we conducted a detailed study of microhabitat use by the swamp rat, Rattus lutreolus, in a native heathland in south‐eastern Australia. Rattus lutreolus typically occurs in late‐succession heath and is frequently associated with high vegetation density. Our assessment of vegetation at trapping stations, and also along trails used by the animals (using the spool‐and‐line tracking technique), revealed strong selection by the rats for dense vegetation by both day and night. The spool‐and‐line tracking approach revealed distinct intraspecific and temporal patterns. During the day, females foraged in vegetation of much higher density than did juveniles, with males behaving intermediately. During the night, however, all animals selected dense vegetation irrespective of sex or age, although the mean density of vegetation selected during the night was lower than it was during the day. These patterns were independent of daily maximum and minimum air temperature and were therefore unlikely to be related to microclimate. We propose instead that high vegetation density acts as a source of protection from predators, allowing R. lutreolus to forage safely both by day and by night.
d‐Alanyl ester depletion of teichoic acids in Lactobacillus reuteri 100‐23 results in impaired colonization of the mouse gastrointestinal tract
Authors: Walter Jens , Loach Diane M. , Alqumber Mohammed , Rockel Christoph , Hermann Corinna , Pfitzenmaier Markus , Tannock Gerald W.
Published: March 2007

The dlt operon of Gram‐positive bacteria encodes proteins required for the incorporation of d‐alanine esters into cell wall‐associated teichoic acids (TA). d‐Alanylation of TA has been shown to be important for acid tolerance, resistance to antimicrobial peptides, adhesion, biofilm formation, and virulence of a variety of pathogenic organisms. The aim of this study was to determine the importance of d‐alanylation for colonization of the gastrointestinal tract by Lactobacillus reuteri 100‐23. Insertional inactivation of the dltA gene resulted in complete depletion of d‐alanine substitution of lipoteichoic acids. The dlt mutant had similar growth characteristics as the wild type under standard in vitro conditions, but formed lower population sizes in the gastrointestinal tract of ex‐Lactobacillus‐free mice, and was almost eliminated from the habitat in competition experiments with the parental strain. In contrast to the wild type, the dlt mutant was unable to form a biofilm on the forestomach epithelium during gut colonization. Transmission electron microscope observations showed evidence of cell wall damage of mutant bacteria present in the forestomach. The dlt mutant had impaired growth under acidic culture conditions and increased susceptibility to the cationic peptide nisin relative to the wild type. Ex vivo adherence of the dlt mutant to the forestomach epithelium was not impaired. This study showed that d‐alanylation is an important cell function of L. reuteri that seems to protect this commensal organism against the hostile conditions prevailing in the murine forestomach.
Mass spectrometric characterization and physiological actions of VPNDWAHFRGSWamide, a novel B type allatostatin in the crab, Cancer borealis
Authors: Fu Qiang , Tang Lamont S. , Marder Eve , Li Lingjun
Published: March 2007

The neural networks in the crustacean stomatogastric ganglion are modulated by neuroactive substances released locally into the neuropil of the stomatogastric ganglion and by circulating hormones released by neuroendocrine structures including the pericardial organs. Using nanoscale liquid chromatography coupled to electrospray ionization quadrupole‐time‐of‐flight mass spectrometry, we have identified and sequenced a novel B type allatostatin (CbAST‐B1), VPNDWAHFRGSWamide, present in the pericardial organs of the crabs, Cancer borealis, and Cancer productus. We describe the physiological actions of CbAST‐B1 on the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis. CbAST‐B1 reduces the pyloric network frequency in a dose‐dependent manner. The effect of bath‐applied CbAST‐B1 depends on the preceding physiological state of the preparation. Surprisingly, despite marked amino‐acid sequence dissimilarity between the novel CbAST‐B1 and the A type allatostatin family of peptides (AST‐A), the physiological effects of CbAST‐B1 are similar to those of AST‐A.
Noradrenaline enhances the expression of the neuronal monocarboxylate transporter MCT2 by translational activation via stimulation of PI3K/Akt and the mTOR/S6K pathway
Authors: Chenal Julie , Pellerin Luc
Published: March 2007

Monocarboxylate transporter 2 (MCT2) expression is up‐regulated by noradrenaline (NA) in cultured cortical neurons via a putative but undetermined translational mechanism. Western blot analysis showed that p44/p42 mitogen‐activated protein kinase (MAPK) was rapidly and strongly phosphorylated by NA treatment. NA also rapidly induced serine/threonine protein kinase from AKT virus (Akt) phosphorylation but to a lesser extent than p44/p42 MAPK. However, Akt activation persisted over a longer period. Similarly, NA induced a rapid and persistent phosphorylation of mammalian target of rapamycin (mTOR), a kinase implicated in the regulation of translation in the central nervous system. Consistent with activation of the mTOR/S6 kinase pathway, phosphorylation of the ribosomal S6 protein, a component of the translation machinery, could be observed upon treatment with NA. In parallel, it was found that the NA‐induced increase in MCT2 protein was almost completely blocked by LY294002 (phosphoinositide 3‐kinase inhibitor) as well as by rapamycin (mTOR inhibitor), while mitogen‐activated protein kinase kinase and p38 MAPK inhibitors had much smaller effects. Taken together, these data reveal that NA induces an increase in neuronal MCT2 protein expression by a mechanism involving stimulation of phosphoinositide 3‐kinase/Akt and translational activation via the mTOR/S6 kinase pathway. Moreover, considering the role of NA in synaptic plasticity, alterations in MCT2 expression as described in this study might represent an adaptation to face energy demands associated with enhanced synaptic transmission.
High aspartate to alanine aminotransferase ratio is an indicator of cirrhosis and poor outcome in patients with primary sclerosing cholangitis
Authors: Nyblom Helena , Nordlinder Hans , Olsson Rolf
Published: March 2007

Objectives: A liver biopsy is performed mainly to stage primary sclerosing cholangitis (PSC). In viral hepatitis, alcoholic liver disease and in primary biliary cirrhosis, the ratio of aspartate to alanine aminotransferase (AST/ALT) has been proven to be an indicator of liver cirrhosis. We wanted to test whether or not an AST/ALT ratio ≥1 is an indicator of cirrhosis also in patients with PSC.

Methods: A cohort of 154 patients diagnosed with PSC was studied retrospectively. Laboratory tests and the histological stage were scored.

Results: The mean AST/ALT ratio in the cirrhotic patients at the time of the first (n=117) as well as the last (n=72) histological examination was higher (1.3±0.5 and 1.6±0.7, respectively) than in the non‐cirrhotic patients (0.7±0.4 and 1.0 ±0.4, respectively) (P<0.0001 and P=0.0002, respectively). An AST/ALT ratio ≥1 was a strong predictor for liver‐related death/orthotopic liver transplantation and liver‐related death, being associated with a double and an almost fourfold higher risk, respectively.

Conclusion: An AST/ALT ratio ≥1 is significantly associated with the presence of cirrhosis and poor outcome in PSC. It may therefore be a valuable non‐invasive method for indicating cirrhosis in patients with PSC.
Impact of non‐alcoholic fatty liver disease on chronic hepatitis B
Authors: Bondini Silvia , Kallman Jillian , Wheeler Angela , Prakash Shivaani , Gramlich Terry , Jondle Daniel M. , Younossi Zobair M.
Published: March 2007

Background: The impact of superimposed non‐alcoholic fatty liver disease (NAFLD) is well established in patients with chronic hepatitis C (CH‐C), but the impact in patients with chronic hepatitis B (CH‐B) is less clear.

Aim: This study aims to evaluate the prevalence of NAFLD in patients with CH‐B and the association with viral and host factors, particularly in patients with metabolic syndrome (MS).

Design: Data from patients with CH‐B was obtained from our databases. Patients with excessive alcohol use were excluded. Hepatitis B virus (HBV) genotyping by INNO‐LIPA was available for some patients. The presence of MS was defined according to the Adult Treatment Panel III (ATP III). All biopsies were read by two hepatopathologists using Metavir, modified histologic activity index (MHAI), as well as a NAFLD pathologic protocol. Patients were classified as (1) those without NAFLD; (2) those with simple hepatic steatosis; (3) and those with superimposed non‐alcoholic steatohepatitis (NASH). Factors associated with superimposed NAFLD, its subtypes, and hepatic fibrosis were also analysed.

Results: Subjects included 153 HBV patients [66% male, age 50.5±27.5 years, body mass index 24.7±3.7 kg/m2, waist 83.2±10.9 cm; 8.5% Caucasian, 67% Asian, aspartate aminotransferase (AST) 63.2±88.2 IU/l, alanine aminotransferase (ALT) 98.6±164.6 IU/l, glucose 111.6±50.5 mg/dl, HBV–DNA 1.8 × 108±1.9 × 106 copies/ml, 7% with MS, 13% with diabetes, 20% with arterial hypertension and 8.5% with dyslipidaemia]. Liver biopsy was available for 64 subjects [19% had superimposed NAFLD, 13% had superimposed NASH, 86% had some degree of fibrosis, and 39% had advanced fibrosis (Ishak >3)]. Patients with HBV and superimposed NASH were significantly older (55 vs. 42 years, P=0.008), more likely to have hypertension (63% vs. 15%, P=0.006) and dyslipidaemia (50% vs. 8%, P=0.006), and had a larger waist circumference (92 vs. 83 cm, P=0.03). The presence of fibrosis was associated with higher waist circumference (84 vs. 80 cm, P=0.03), higher HBV‐DNA (1.9 × 108 vs. 5 × 106 copies/ml, P=0.005), and elevated ALT >40 IU/l (73.6% vs. 33.3%, P=0.02).

Conclusions: The components of MS (obesity, hypertension, and dyslipidaemia) are associated with the presence of NASH in patients with CH‐B. The presence of hepatic fibrosis seems to be associated with known host and viral factors as well as the presence of abdominal obesity.
Strategic Outsourcing Decisions for Manufacturers that Produce Partially Substitutable Products in a Quantity‐Setting Duopoly Situation*
Authors: Xiao Tiaojun , Xia Yusen , Zhang G. Peter
Published: March 2007

This article examines production and outsourcing decisions for two manufacturers that produce partially substitutable products and play a strategic game with quantity competition. When both manufacturers outsource key components to the same upstream supplier, their products become more substitutable due to the increased commonality of the products. In addition, outsourcing may create better consumer perception about the product if the manufacturers choose reputable suppliers with better brand or quality. We explicitly model the substitutability change and the brand/quality effect and provide conditions under which the manufacturers should outsource the components to a supplier. We present the subgame perfect Nash equilibriums for the situation in which there is only one supplier and the case in which two suppliers compete with each other in the upstream supply chain. Numerical examples are presented to illustrate the findings.
The FAIRSERV Model: Consumer Reactions to Services Based on a Multidimensional Evaluation of Service Fairness
Authors: Carr Christopher L.
Published: March 2007

The current dominant conceptualization of consumer reactions to services is the SERVQUAL model. This article proposes the FAIRSERV model as an alternative or additional conceptualization of consumer reactions to services. FAIRSERV involves seeing service evaluation through the lens of organizational fairness (justice) theory applied to the relationship between the service consumer and the service provider. FAIRSERV is premised on the claim that, especially in relational service contexts, consumers are interested in service fairness as well as service quality (service favorableness) as represented by SERVQUAL. Service fairness or justice is a multidimensional construct based on equity theory. In this article, the FAIRSERV model is tested with the SERVQUAL model in the context of information system services. The two models are used to predict service satisfaction and repatronage intention. The FAIRSERV model appears to add a significant new set of predictors of service satisfaction and repatronage intention that should be considered in the future by service providers.
Risk Management: The Unifying Framework for Business Scholarship and Pedagogy
Authors: Garven James R.
Published: March 2007

Abstract

In this article, I provide a brief critical assessment of the intellectual history of risk management and insurance (RMI) as an academic discipline. Although the level of rigor and overall quality of RMI scholarship and pedagogy continue to improve, RMI remains too narrowly focused upon risk management issues specifically affecting insurance markets and institutions. Since risk management is of fundamental importance to virtually all areas of business scholarship and pedagogy, we must seek ways to more broadly apply risk management concepts.
Unfair Discrimination and Homeowners Insurance Availability: An Empirical Analysis
Authors: Regan Laureen
Published: March 2007

Abstract

There has been an active public policy debate about the availability and cost of homeowners insurance in urban markets, and insurers have been charged with intentional discrimination, or redlining, against minority buyers and neighborhoods with a large proportion of minority population. Studies of relative price, loss costs, agency location, and product quality have attempted to determine whether insurers unfairly discriminate against minority homeowners in urban areas. This study focuses on insurance availability, and examines whether there is a systematic difference in the breadth of insurance coverage in the market that corresponds to the proportion of minority residents in a state. The market share of dwelling fire insurance polices across states for years 2000 and 2003 is analyzed, and evidence is presented that shows a positive correlation between the proportion of minority homeowners in a state and the share of more restrictive dwelling fire policies. However, this difference is not statistically significant once other risk‐related and economic factors are included in the analysis.
The Solvency II Process: Overview and Critical Analysis
Authors: Eling Martin , Schmeiser Hato , Schmit Joan T.
Published: March 2007

Abstract

As early as the 1970s, European Union (EU) member countries implemented rules to coordinate insurance markets and regulation. However, with the more recent movement toward a general single EU market, financial services regulation has taken on new meaning and priority. Solvency I regulations went into effect for member nations by January 2004. The creation of risk‐based capital standards, the main focus of Solvency II, now appears likely sometime after 2007. The purpose of the discussion presented here is to outline the specifics of Solvency II as they currently stand and suggest important areas of future research.
Melatonin enhances the rewarding properties of morphine: involvement of the nitric oxidergic pathway
Authors: Yahyavi‐Firouz‐Abadi Noushin , Tahsili‐Fahadan Pouya , Ghahremani Mohammad Hossein , Dehpour Ahmad Reza
Published: March 2007

Abstract:  Melatonin has different interactions with opioids including the enhancement of the analgesic effects of morphine and also reversal of tolerance and dependence to morphine. The present study assessed the effect of melatonin on morphine reward in mice using a conditioned place preference (CPP) paradigm. Our data showed that subcutaneous administration of morphine (1–7.5 mg/kg) significantly increased the time spent in the drug‐paired compartment in a dose‐dependent manner. Intraperitoneal (i.p.) administration of melatonin (1–40 mg/kg) alone did not induce either CPP or conditioned place aversion (CPA), while the combination of melatonin (5–20 mg/kg) and sub‐effective dose of morphine (0.5 mg/kg) led to rewarding effect. We further investigated the involvement of the nitric oxidergic pathway in the enhancing effect of melatonin on morphine CPP, by a general nitric oxide synthase inhibitor, NG‐nitro‐l‐arginine methyl ester (l‐NAME). l‐NAME (1 and 5 mg/kg, i.p.) alone or in combination with morphine (0.5 mg/kg) did not show any significant CPP or CPA. Co‐administration of l‐NAME (5 mg/kg) with an ineffective combination of melatonin (1 mg/kg) plus morphine (0.5 mg/kg) produced significant CPP that may imply the similarity of action of melatonin and l‐NAME and involvement of the nitric oxidergic pathway in this regard. Our results indicate that pretreatment of animals with melatonin enhances the rewarding properties of morphine via a mechanism which may involve the nitric oxidergic pathway.