bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of carbohydrate ingestion on brain exchange of amino acids during sustained exercise in human subjects
Authors: Blomstrand E. , Møller K. , Secher N. H. , Nybo L.
Published: October 2005

Aim:  This study investigated the effect of prolonged exercise with and without carbohydrate intake on the brain exchange of amino acids, especially focussing on tryptophan and branched‐chain amino acids (BCAA).

Methods:  Five male subjects exercised for 3 h on a cycle ergometer at 200 ± 7 W on two occasions; either supplemented with a 6% carbohydrate solution or with flavoured water (placebo). Catheters were inserted into the right internal jugular vein and the radial artery of the non‐dominant arm. The brain exchange of amino acids during exercise was calculated from the arterial‐jugular venous concentration difference multiplied by plasma flow.

Results:  About 106 μmol (22 mg) of tryptophan was taken up by the brain during exercise in the placebo trial, whereas no significant uptake was observed in the carbohydrate trial. In accordance, the arterial concentration of free tryptophan increased from 12 ± 1 to 20 ± 2 μmol L−1 during the placebo trial and was significantly higher compared with the glucose trial (14 ± 1 μmol L−1 at the end of exercise). Also, the arterial concentration of total tryptophan (free and albumin‐bound) increased during the first 30 min of exercise in both trials, but returned to the basal level at 180 min of exercise. In both trials, BCAA were taken up by the brain while glutamine was released.

Conclusion:  The present data show that both tryptophan and BCAA are taken up by the brain during prolonged exercise, and we suggest that the cerebral uptake of tryptophan may relate to increased synthesis of serotonin (5‐HT) in the brain.
Effects of innervation state on Hsp25 content and phosphorylation in inactive rat plantaris muscles
Authors: Huey K. A. , Hyatt J.‐P. K. , Zhong H. , Roy R. R.
Published: October 2005

Aim:  Previous reports suggest a role for neuromuscular activity levels and/or connectivity in modulating Hsp25 expression and phosphorylation (pHsp25) in skeletal muscles. However, pHsp25 has only been studied in denervated muscles and/or muscles exposed to high levels of residual neuromuscular activity. Spinal cord isolation (SI) provides a model in which the muscle is exposed to nearly complete inactivity with maintenance of the nerve–muscle connection. To parcel out the roles of innervation state and activity‐independent neural factors, we compared Hsp25 and pHsp25 in the plantaris of control (Con), SI, and denervated (Den, inactivity without neural connectivity) rats.

Methods:  Hsp25 and pHsp25 protein levels (soluble and insoluble fractions) were measured with Western blot analysis after 1, 3, 8, 14, or 28 days of SI or Den. pHsp25 was normalized to non‐pHsp25 at each time point.

Results:  Hsp25 was unchanged (days 1, 3 and 14) or increased (days 8 and 28) in the soluble fraction, and decreased (day 1) or increased (days 3, 8 and 14) in the insoluble fraction in Den compared with Con rats. pHsp25 was reduced after 1 and 28 days of Den, but near control levels on days 3, 8, and 14 in the soluble fraction. In the insoluble fraction, pHsp25 levels were lower in Den than Con rats on all days. In both fractions, Hsp25 was lower in SI than Con rats. pHsp25 levels were lower in the soluble fraction and higher in the insoluble fraction in SI than Con rats.

Conclusion:  These results suggest that an intact innervation, even in the absence of muscle activation and/or loading, is critical for Hsp25 phosphorylation in the insoluble fraction. However, the time‐dependent decrease in Hsp25 with SI suggests a role for minimal levels of muscle activation and/or loading in maintaining Hsp25 expression during sustained inactivity.
Mitochondrial efficiency in rat skeletal muscle: influence of respiration rate, substrate and muscle type
Authors: Mogensen M. , Sahlin K.
Published: October 2005

Aim:  To investigate the hypothesis that mitochondrial efficiency (i.e. P/O ratio) is higher in type I than in type II fibres during submaximal rates of respiration.

Methods:  Mitochondria were isolated from rat soleus and extensor digitorum longus (EDL) muscles, representing type I and type II fibres, respectively. Mitochondrial efficiency (P/O ratio) was determined with pyruvate (Pyr) or palmitoyl‐l‐carnitine (PC) during submaximal (constant rate of adenosine diphosphate infusion) and maximal (Vmax, state 3) rates of respiration and fitted to monoexponential functions.

Results:  There was no difference in Vmax between PC and Pyr in soleus but in EDL Vmax with PC was only 58% of that with Pyr. The activity of 3‐hydroxyacyl‐CoA dehydrogenase was threefold higher in soleus than in EDL. P/O ratio at Vmax was 8–9% lower with PC [2.33 ± 0.02 (soleus) and 2.30 ± 0.02 (EDL)] than with Pyr [2.52 ± 0.03 (soleus) and 2.54 ± 0.03 (EDL)] but not different between the two muscles (P > 0.05). P/O ratio was low at low rates of respiration and increased exponentially when the rate of respiration increased. The asymptotes of the curves were similar to P/O ratio at Vmax. P/O ratio at submaximal respirations was not different between soleus and EDL neither with Pyr nor with PC.

Conclusion:  Mitochondrial efficiency, as determined in vitro, was not significantly different in the two fibre types neither at Vmax nor at submaximal rates of respiration. The low Vmax for PC oxidation in EDL may relate to low activity of β‐oxidation.
Spectrum of infection, risk and recommendations for prophylaxis and screening among patients with lymphoproliferative disorders treated with alemtuzumab*
Authors: Thursky Karin A. , Worth Leon J. , Seymour John F. , Miles Prince H. , Slavin Monica A.
Published: October 2005

There is an increasing use of monoclonal antibodies in the treatment of haematological malignancies. Alemtuzumab (Campath‐1H; Ilex Pharmaceuticals, San Antonio, TX, USA) is a monoclonal antibody reactive with the CD52 antigen used as first and second line therapy for two types of lymphoproliferative disorders: chronic lymphocytic leukaemia (CLL), and T‐cell lymphomas [both peripheral (PTCL) and cutaneous (CTCL)]. With alemtuzumab therapy, viral, bacterial and fungal infectious complications are frequent, and may be life threatening. An understanding of the patients at highest risk and duration of risk are important in developing recommendations for empirical management, antimicrobial prophylaxis and targeted surveillance. This review discusses the infection risks associated with these lymphoproliferative disorders and their treatment, and provide detailed recommendations for screening and prophylaxis.
The relationship between maternal depression and child outcomes in a child welfare sample: implications for treatment and policy
Authors: Leschied Alan W. , Chiodo Debbie , Whitehead Paul C. , Hurley Dermot
Published: October 2005

Maternal depression is an extremely important parenting variable in relation to child general health. This investigation addressed the issue of maternal depression as it relates to the lives of children seen by child welfare authorities. Maternal depression was investigated in the context of the increasing rate of children coming to the attention of the London and Middlesex Children's Aid Society. A variety of child outcomes including those of particular relevance to child welfare, specifically disorders of attachment and neglect and physical abuse, school‐related variables, conduct disorder and psychological distress, were investigated. The relative contribution of maternal depression along with measures of socioeconomic status and social isolation to childhood risk was examined. Results indicated that the rate of maternal depression doubled during the years 1995–2001. Maternal depression was related to children entering care through wardship. Additional poor child outcomes such as attention deficit disorder, conduct disorder and emotional adjustment were also related to maternal depression. The findings are discussed in terms of treatment and policies that can lower the risk to children through effective intervention with depressed mothers.
Fatherhood and immigration: challenging the deficit theory
Authors: Roer‐Strier Dorit , Strier Roni , Este David , Shimoni Rena , Clark Dawne
Published: October 2005

Most immigration studies focus on the negative consequences of immigration for families and for parenting. Immigration is also viewed as a factor that undermines fathers’ capacity to implement their fathering roles. The impact of immigration on fathers has received very little attention. This paper is based on 54 interviews with immigrant fathers to Canada and Israel. Based on qualitative data, the paper investigates immigrant fathers’ perceptions of fatherhood in the midst of cultural change. This paper challenges the widely held notion that immigration itself is a risk factor for fatherhood. It focuses rather on the systemic barriers and obstacles facing immigrant fathers in their new country and the positive opportunities this change presents. Implications for intervention and policies concerning immigrant families are discussed.
Beyond attachment theory and therapy: Towards sensitive and evidence‐based interventions with foster and adoptive families in distress
Authors: Barth Richard P. , Crea Thomas M. , John Karen , Thoburn June , Quinton David
Published: October 2005

Elements of attachment theory have been embraced by practitioners endeavouring to assist foster and adopted children and their parents. Attachment theory articulates the potential risks of experiencing multiple caregivers; emphasizes the importance of close social relationships to development; and recognizes that substitute parents may not always have close relationships with children who have experienced adversities before joining them. Attachment theory offers concerned parents what they believe to be a scientific explanation about their lack of the close, satisfying parent–child relationship they desire. Yet the scientific base of attachment theory is limited both in terms of its ability to predict future behaviours, and especially with regard to its use as the underpinning theory for therapeutic intervention with children experiencing conduct problems. There is a critical need to review the role of attachment theory in child and family services and to consider its place among other explanations for children's disturbing behaviour. An important step towards pursuing alternative approaches is for researchers and practitioners to understand the reasons the attachment paradigm appeals to so many adoptive and foster parents, given the apparent widespread prevalence of attachment‐based interventions. Such understanding might assist in the development of adoption‐sensitive uses of appropriate evidence‐based treatment approaches.
Research Review: Parents’ service experience – a missing element in research on foster care case outcomes
Authors: Alpert Lily T.
Published: October 2005

A large body of child protection literature focuses on termination of parental rights, family reunification, and children's re‐entry into care as outcomes for children in foster care. Studies have investigated child, placement, family, and parent variables as predictors of case outcome. However, one important group of variables remains largely unstudied: factors related to parents’ service experience. Parents’ service experience includes parents’ perceptions of and involvement in the various services in which they must participate in order to recover their children from foster care (e.g. mandated treatment programmes such as substance abuse rehabilitation, parenting skills classes, etc.). The parental perspective on the foster care process is a critical element in the life of a child protection case, and its influence on case outcome must be explored. A brief review of the current literature on case outcome predictors is provided and parents’ service experience is highlighted as an area in need of investigation. Suggestions for the measurement of parents’ service experience are also offered.
Variance in isotopic signatures as a descriptor of tissue turnover and degree of omnivory
Authors: SWEETING C. J. , JENNINGS S. , POLUNIN N. V. C.
Published: October 2005

Diet analyses using C and N stable isotopes commonly focus on mean isotopic signatures; however, isotopic variance among individuals is likely to also contain useful information including details of omnivory.

Changes in isotopic signature as a result of dietary shifts are not instantly manifest in the isotopic signature of consumer tissues, but lagged over a period of time required for equilibration. Tissue turnover times have not previously been described in terms of variance in isotopic signature among individuals, and variance among individuals following equilibration with a constant diet is limited.

Temporal changes in δ15N and δ13C variance in juvenile European Sea Bass (Dicentrarchus labrax) muscle, heart and liver were monitored following a shift from a wild diet to two single‐source diets administered under seminatural conditions in captivity. Exponential decay functions of the standard deviation of δ15N and δ13C among individuals were used to model changes in variance over time.

All tissues exhibited a similar rate of tissue turnover using variance. However, variance among individuals within tissue types differed once fishes were equilibrated with the laboratory diet. The coefficients of variation of δ13C and δ15N were smallest in muscle and greatest in liver and greater among sampling dates than within.

Analysis of δ15N and δ13C in different tissues will not therefore provide equivalent power to detect differences in diet or to track changes in patterns of omnivory. Analysis of omnivory should be restricted to variance from a single tissue type. Of the tissues considered here, white muscle is most appropriate for this purpose.

Variance estimates derived here provide minimum values expected for a highly specialist feeding population. Departure from these values can be used to describe the degree of omnivory within a population.
Defects in ProTaper S1 instruments after clinical use: fractographic examination
Authors: Cheung G. S. P. , Peng B. , Bian Z. , Shen Y. , Darvell B. W.
Published: October 2005

Aim  To investigate the mode of failure of a brand of nickel‐titanium instruments separated during clinical use, by detailed examination of the fracture surface.

Methodology  A total of 122 ProTaper S1 instruments were discarded from an endodontic clinic at a stomatological school in China over a period of 17 months; 28 had fractured. These fractured instruments were ultrasonically cleaned, autoclaved and then examined under a scanning electron microscope. From the lateral view the fracture was classified into ‘torsional’ or ‘flexural’. The specimens were then re‐mounted and the presence of characteristics of shear failure and fatigue striations was recorded under high‐power view of the fracture surface. The difference in the mean lengths of fractured segment between the shear and fatigue groups was compared using Student's t‐test.

Results  Twenty‐seven separated instruments were available for analysis. Under low‐power magnification, only two fell into the category of ‘torsional’ failure when examined laterally; the others appeared to be ‘flexural’. Close examination of the fracture surface revealed the presence of fatigue striations in 18 specimens. Nine instruments (including the two putative ‘torsional’ failures above) fell into the shear fracture group, in which fatigue striations were absent or characteristics of shear failure of the material were found. The mean length of fractured segments resulting from fatigue failure (4.3 ± 1.9 mm) was significantly greater than that for shear failure (2.5 ± 0.8 mm) (P < 0.001, two‐sample t‐test).

Conclusions  Examination of the fracture surface at high magnification is essential to reveal features that may indicate the possible origin of cracks and the mode of material failure. Macroscopic or lateral examination of separated instruments would fail to reveal the true mechanism of failure. Fatigue seems to be an important reason for the separation of rotary instruments during clinical use.
Reduction of osteocalcin expression in aged human dental pulp
Authors: Muramatsu T. , Hamano H. , Ogami K. , Ohta K. , Inoue T. , Shimono M.
Published: October 2005

Aim  To investigate the expression of osteocalcin mRNA in young and in aged human dental pulp tissue to determine the characteristics of osteocalcin expression.

Methodology  Human dental pulp tissues of the third molars were obtained from healthy young (17–23 years) and aged (>50 years) subjects, and total RNA was extracted. Osteocalcin mRNA expression was determined by RT‐PCR and by quantitative real‐time RT‐PCR (QRT‐PCR). The threshold cycle (Ct) value, which reflects the amount of PCR, was calculated and the difference between the value in young and aged pulp was statistically analysed.

Results  Osteocalcin mRNA was detected in all samples of human dental pulp tissue homogenates by RT‐PCR analysis. Osteocalcin mRNA was expressed in young adult dental pulp but was decreased in aged human dental pulp. QRT‐PCR analysis also showed a reduced expression of osteocalcin mRNA in aged human pulp. Expression of osteocalcin in young human pulp was significantly higher (about sixfold) than in aged pulp (P < 0.01, Mann–Whitney U‐test).

Conclusion  Reduction of osteocalcin expression may be associated with the loss of viability in human dental pulp tissue, and may be a characteristic of aged human dental pulps.
Ultrastructural alterations of frozen‐thawed Asian elephant (Elephas maximus) spermatozoa
Authors: SA‐ARDRIT M. , SAIKHUN J. , THONGTIP N. , DAMYANG M. , MAHASAWANGKUL S. , ANGKAWANISH T. , JANSITTIWATE S. , FAISAIKARM T. , KITIYANANT Y. , PAVASUTHIPAISIT K. , PINYOPUMMIN A.
Published: October 2005

Intact plasma and acrosome membranes and functional mitochondria following cryopreservation are important attributes for the fertilizing ability of spermatozoa. In the present study, functional and ultrastructural changes of Asian elephant spermatozoa after cryopreservation either in TEST + glycerol or HEPT + dimethyl sulphoxide (DMSO) were evaluated by fluorescent techniques and electron microscopy. Sperm frozen in TEST + glycerol had higher proportion of sperm with intact plasma (49.1 ± 9.2% vs. 30.9 ± 3.9%) and acrosomal (53.7 ± 4.9% vs. 35.8 ± 6.1%) membranes, as well as active mitochondria (57.0 ± 7.2% vs. 42.0 ± 5.0%) than those cryopreserved in HEPT + DMSO. The results obtained from electron microscopy were similar to those obtained by fluorescence microscopy. The percentage of normal spermatozoa was higher when spermatozoa were frozen in TEST + glycerol than those frozen in HEPT + DMSO (31.8 ± 5.6 vs. 28.5 ± 6.4). The ultrastructural alterations revealed by transmission electron microscopy could be classified as (i) distension of plasma membrane, while the acrosome was swollen; (ii) disruption or loss of plasma membrane, while acrosome was swollen with distended outer acrosomal membrane; (iii) disruption or loss of plasma and outer acrosomal membrane with leakage of acrosome content; (iv) extensive vesiculation of plasma and outer acrosomal membrane and leakage of acrosome content; (v) a complete loss of both plasma membrane and outer acrosomal membrane; and (vi) swelling of mitochondria. These findings suggest that the freezing and thawing procedure caused structural damage to elephant spermatozoa, especially in the plasma membrane, acrosome and mitochondria. Fluorescence and electron microscopic evaluations are potentially a powerful tool in the analysis of elephant spermatozoa after freezing and thawing.
Reduced foraging efficiency of a parasitoid under habitat complexity: implications for population stability and species coexistence
Authors: GOLS R. , BUKOVINSZKY T. , HEMERIK L. , HARVEY J. A. , VAN LENTEREN J. C. , VET L. E. M.
Published: October 2005

Habitat complexity may stabilize interactions among species of different trophic levels by providing refuges to organisms of lower trophic levels.

Searching behaviour of the parasitoid,Diadegma semiclausum, was followed in different semifield set‐ups, a low and high‐density monoculture ofBrassica oleraceaand two intercrops,B. oleraceawithSinapis alba(also a member of the Brassicaceae) andB. oleraceawithHordeum vulgare(Poaceae).

When a low‐density monocrop ofB. oleraceawas compared with a high‐density monocrop, no differences were found in the ability of the female wasps to locate a host‐infested plant,B. oleracea, infested withPlutella xylostellathat was placed in the centre of the set‐up.

The efficiency of the parasitoid to locate the host‐infested plant was differentially affected by the species composition of the vegetation. Wasps entered theSinapis‐Brassicaset‐up faster, but took more time to find the host‐infested plant than in theHordeum‐Brassicaset‐up.

The horizontal arrangement, i.e. by mixingS. albaorH. vulgarewith, or placing them as rows betweenB. oleracea, did not affect host‐finding efficiency.

Plant height did influence host finding. Wasps found the host‐infested plants earlier in the set‐up with shortSinapisplants compared with tallSinapisplants.

Once the wasps had landed on the host‐infested plant, the surrounding vegetation did not affect time needed to parasitize five consecutive hosts on the same infested plant, regardless of the composition or horizontal/vertical arrangement of the set‐up.

Chemical and structural refuges in complex landscapes may play an important role in the persistence of this system through dampening oscillations of parasitoid and host populations.
Vole cycles and predation in temperate and boreal zones of Europe
Authors: KORPIMÄKI ERKKI , OKSANEN LAURI , OKSANEN TARJA , KLEMOLA TERO , NORRDAHL KAI , BANKS PETER B.
Published: October 2005

Graham & Lambin (2002) have reported on a weasel‐reduction experiment, concluding that the impact of weasel predation on field vole survival was neither sufficient nor necessary to initiate and drive the cyclic decline of field vole populations in Kielder Forest, northern England. They also stated that their findings contradict conclusively the specialist predator hypothesis put forward to explain population cycles of voles in North Europe.

Straightforward inferences from Kielder Forest to the northern boreal zone are misleading, because the population cycles of voles in Kielder Forest differ essentially from North European vole cycles. The low amplitude of the vole cycles in Kielder Forest, their restricted spatial synchrony in comparison to northern Europe and the virtual lack of interspecific synchrony in Kielder Forest suggest that there are essential differences between the mechanisms responsible for the two types of cyclic fluctuations of voles.

The weasel‐reduction experiment may provide a misleading picture on the role of predators, even in the Kielder Forest cycle. The experimental reduction of weasels alone may not stop the population decline of voles, because competing larger predators are expected to increase their hunting in the weasel‐reduction areas. The small spatial scale of the experiment, which produced only slight, short‐term differences in weasel densities between reduction and control areas, also suggests that other predators could have compensated easily for the weasels that were removed.

We propose a new version of the predation hypothesis to explain low‐amplitude population cycles of voles in temperate Europe, including the Kielder Forest. The interaction between generalist predators and vole populations might account for these cycles because generalists can have a functional response that is destabilizing in the neighbourhood of the equilibrium point. As most generalists are orders of magnitude larger than weasels, and thus need much more food for survival, generalist‐driven cycles should be characterized by high prey minima, as observed in Kielder Forest.
Using historical ecology to understand patterns of biodiversity in fragmented agricultural landscapes
Authors: Lunt Ian D. , Spooner Peter G.
Published: October 2005

Aim  To enhance current attempts to understand biodiversity patterns by using an historical ecology approach to highlight the over‐riding influence of land‐use history in creating past, current and future patterns of biodiversity in fragmented agricultural landscapes.

Methods  We develop an integrative conceptual framework for understanding spatial and temporal variations in landscape patterns in fragmented agricultural landscapes by presenting five postulates (hypotheses) which highlight the important role of historical, anthropogenic disturbance regimes. We then illustrate each of these postulates with examples drawn from fragmented woodlands in agricultural areas of south‐eastern Australia, and discuss these findings in an international context. Location examples are drawn from agricultural areas in south‐eastern Australia.

Results  We conclude that there is limited potential to refine our understanding of patterns of biodiversity in human‐modified landscapes based on traditional concepts of island biogeography, or simple assumptions of ongoing destruction and degradation. Instead, we propose that in agricultural landscapes that were largely cleared over a century ago: (1) present‐day remnant vegetation patterns are not accidental, but are logically arrayed due to historic land‐use decisions, (2) historic anthropogenic disturbances have a major influence on current ecosystem conditions and diversity patterns, and (3) the condition of remnant ecosystems is not necessarily deteriorating rapidly.

Main conclusions  An historical ecology approach can enhance our understanding of why different species and ecosystem states occur where they do, and can explain internal variations in ecological conditions within remnant ecosystems, too often casually attributed to the ‘mess of history’. This framework emphasizes temporal changes (both past and future) in biotic patterns and processes in fragmented agricultural landscapes. Integration of spatially and temporally explicit historical land‐use information into ecological studies can prove extremely useful to test hypotheses of the effects of changes in landscape processes, and to enhance future research, restoration and conservation management activities.
Inter‐ and intraspecific phylogeography of small mammals in the Atacama Desert and adjacent areas of northern Chile
Authors: Eduardo Palma R. , Marquet Pablo A. , Boric‐Bargetto Dusan
Published: October 2005

Aim  We evaluated the phylogeography of sigmodontine taxa of the genera Phyllotis and Abrothrix at the intra and interspecific level, in the Atacama desert and adjacent Andean and Puna regions of northern Chile. The major goal was to test the hypothesis that sigmodontine mice differentiated in the lowlands, most likely via peripatric speciation, dispersing from highland to lowland areas across the desert vegetated canyons, thus reaching the Pacific coast. Dispersing individuals may have found favourable habitats along these valleys, in northern Chile, which connect the high altitude Puna region with the lowlands.

Location  The study was conducted in northern Chile (18–22° S), in coastal pre‐Puna and Puna regions.

Methods  For phylogeographic analyses we analysed cytochrome b mitochondrial sequences for 29 specimens of the genera Abrothrix and Phyllotis, from the region of study. All results were analysed phylogenetically using maximum‐likelihood, Bayesian, and uncorrected median‐joining network methodology.

Results  In Phyllotis we recognized two major clusters of taxa: one restricted to the Puna region identified as Phyllotis xanthopygus chilensis, in close association to a pre‐Punean and lowland clade constituted by Phyllotis limatus, on the western slopes of the Andes. A similar pattern was distinguished for Abrothrix, where Abrothrix andinus was recognized in the Andean Altiplano‐pre‐Puna region and Abrothrix olivaceus in the lowlands of northern Chile.

Main conclusions  We found that the radiation of sigmodontine mice in the central Andes may have been facilitated by the historical events that affected high Andean elevations during Pleistocene times, as well as changes in the vegetation composition and climate that started to prevail during that time. Our results also support previous hypotheses that the major mode of evolution for small mammals in the Andes region has been based on the founder effect or the peripheral isolates model, from a central range located in the Andes.
The large form of ADAR 1 is responsible for enhanced hepatitis delta virus RNA editing in interferon‐α‐stimulated host cells
Authors: Hartwig D. , Schütte C. , Warnecke J. , Dorn I. , Hennig H. , Kirchner H. , Schlenke P.
Published: October 2005

Summary.  Hepatitis delta virus (HDV) RNA editing controls the formation of hepatitis‐delta‐antigen‐S and ‐L and therefore indirectly regulates HDV replication. Editing is thought to be catalysed by the adenosine deaminase acting on RNA1 (ADAR1) of which two different forms exist, interferon (IFN)‐α‐inducible ADAR1‐L and constitutively expressed ADAR1‐S. ADAR1‐L is hypothesized to be a part of the innate cellular immune system, responsible for deaminating adenosines in viral dsRNAs. We examined the influence of both forms on HDV RNA editing in IFN‐α‐stimulated and unstimulated hepatoma cells. For gene silencing, an antisense oligodeoxyribonucleotide against a common sequence of both forms of ADAR1 and another one specific for ADAR1‐L alone were used. IFN‐α treatment of host cells led to approximately twofold increase of RNA editing compared with unstimulated controls. If ADAR1‐L expression was inhibited, this substantial increase in editing could no longer be observed. In unstimulated cells, ADAR1‐L suppression had only minor effects on editing. Inhibition of both forms of ADAR1 simultaneously led to a substantial decrease of edited RNA independently of IFN‐α‐stimulation. In conclusion, the two forms of ADAR1 are responsible almost alone for HDV editing. In unstimulated cells, ADAR1‐S is the main editing activity. The increase of edited RNA under IFN‐α‐stimulation is because of induction of ADAR1‐L, showing for the first time that this IFN‐inducible protein is involved in the base modification of replicating HDV RNA. Thus, induction of ADAR1‐L may at least partially cause the antiviral effect of IFN‐α in natural immune response to HDV as well as in case of therapeutic administration of IFN.
Patterns of hybridization and population genetic structure in the terrestrial orchids Liparis kumokiri and Liparis makinoana (Orchidaceae) in sympatric populations
Authors: CHUNG MI YOON , NASON JOHN D. , CHUNG MYONG GI
Published: October 2005

We investigated the potential for gene flow and genetic assimilation via hybridization between common and rare species of the terrestrial orchid genus Liparis, focusing specifically on sympatric and allopatric populations of the common Liparis kumokiri and the rare Liparis makinoana. We utilized analyses of genetic diversity, morphology, and the spatial distributions of individuals and genotypes to quantify the dynamics of interspecific gene flow at within‐ and among‐population scales. High levels of allozyme genetic diversity (HE) were found in populations of the rare L. makinoana (0.317), whereas the common L. kumokiri (N = 1744 from 14 populations) revealed a complete lack of variation. This contrast may reflect different breeding systems and associated rates of genetic drift (L. makinoana is self‐incompatible, whereas L. kumokiri is self‐compatible). At the two known sympatric sites, individuals were found that recombined parental phenotypes, possessing floral characteristics of L. kumokiri and vegetative characteristics of L. makinoana. These putative hybrids were the only individuals found segregating alleles diagnostic of both parental species. Analysis of these individuals indicated that hybrid genotypes were skewed towards L. kumokiri and later generation recombinants of L. kumokiri at both sympatric sites. Furthermore, Ripley's bivariate L(r) statistics revealed that at one site these hybrids are strongly spatially clustered with L. kumokiri. Nonetheless, the relatively low frequency of hybrids, absence of ongoing hybridization (no F1s or first generation backcrossess), and strong genetic differentiation between morphologically ‘pure’ parental populations at sympatric sites (FST = 0.708–0.816) indicates that hybridization was not an important bridge for gene flow. The results from these two species suggest that natural hybridization has not played an important role in the diversification of Liparis, but instead support the view that genetic drift and limited gene flow are primarily responsible for speciation in Liparis. Based on genetic data and current status of the species, implications of the research for conservation are considered to provide guidelines for appropriate conservation and management strategies.
The voyage of an invasive species across continents: genetic diversity of North American and European Colorado potato beetle populations
Authors: GRAPPUTO ALESSANDRO , BOMAN SANNA , LINDSTRÖM LEENA , LYYTINEN ANNE , MAPPES JOHANNA
Published: October 2005

The paradox of successful invading species is that they are likely to be genetically depauperate compared to their source population. This study on Colorado potato beetles is one of the few studies of the genetic consequences of continent‐scale invasion in an insect pest. Understanding gene flow, population structure and the potential for rapid evolution in native and invasive populations offers insights both into the dynamics of small populations that become successful invaders and for their management as pests. We used this approach to investigate the invasion of the Colorado potato beetle (Leptinotarsa decemlineata) from North America to Europe. The beetles invaded Europe at the beginning of the 20th century and expanded almost throughout the continent in about 30 years. From the analysis of mitochondrial DNA (mtDNA) and amplified fragment length polymorphism (AFLP) markers, we found the highest genetic diversity in beetle populations from the central United States. The European populations clearly contained only a fraction of the genetic variability observed in North American populations. European populations show a significant reduction at nuclear markers (AFLPs) and are fixed for one mitochondrial haplotype, suggesting a single successful founder event. Despite the high vagility of the species and the reduction of genetic diversity in Europe, we found a similar, high level of population structure and low gene flow among populations on both continents. Founder events during range expansion, agricultural management with crop rotation, and selection due to insecticide applications are most likely the causes partitioning genetic diversity in this species.
Identification and molecular characterization of an N‐acetylmuramyl‐l‐alanine amidase Sle1 involved in cell separation of Staphylococcus aureus
Authors: Kajimura Junko , Fujiwara Tamaki , Yamada Sakuo , Suzawa Yoshika , Nishida Tetsuya , Oyamada Yoshihiro , Hayashi Ikue , Yamagishi Jun–ichi , Komatsuzawa Hitoshi , Sugai Motoyuki
Published: October 2005

We purified a peptidoglycan hydrolase involved in cell separation from a Staphylococcus aureus atl null mutant and identified its gene. Characterization of the gene product shows a 32 kDa N‐acetylmuramyl‐l‐alanine amidase that we designated Sle1. Analysis of peptidoglycan digests showed Sle1 preferentially cleaved N‐acetylmuramyl‐l‐Ala bonds in dimeric cross‐bridges that interlink the two murein strands in the peptidoglycan. An insertion mutation of sle1 impaired cell separation and induced S. aureus to form clusters suggesting Sle1 is involved in cell separation of S. aureus. The Sle1 mutant revealed a significant decrease in pathogenesis using an acute infection mouse model. Atl is the major autolysin of S. aureus, which has been implicated in cell separation of S. aureus. Generation of an atl/sle1 double mutant revealed that the mutant cell separation was heavily impaired suggesting that S. aureus uses two peptidoglycan hydrolases, Atl and Sle1, for cell separation. Unlike Atl, Sle1 is not directly involved in autolysis of S. aureus.
Candida albicans serotype B strains synthesize a serotype‐specific phospholipomannan overexpressing a β‐1,2‐linked mannotriose
Authors: Trinel Pierre‐André , Delplace Florence , Maes Emmanuel , Zanetta Jean‐Pierre , Mille Céline , Coddeville Bernadette , Jouault Thierry , Strecker Gérard , Poulain Daniel
Published: October 2005

Candida albicans strains consist of serotypes A and B depending on the presence of terminal β‐1,2‐linked mannose residues in the acid‐stable part of serotype A phosphopeptidomannan (PPM). The distribution of C. albicans serotypes varies according to country and human host genetic and infectious backgrounds. However, these epidemiological traits have not yet been related to a phenotypically stable molecule as cell surface expression of the serotype A epitope depends on the growth conditions. We have shown that C. albicans serotype A associates β‐mannose residues with another molecule, phospholipomannan (PLM), which is a member of the mannoseinositolphosphoceramide family. In this study, PLM from serotype B strains was analysed in order to provide structural bases for the differences in molecular mass and antigenicity observed between PLMs from both serotypes. Through these analyses, carbon 10 was shown to be the location of a second hydroxylation of fatty acids previously unknown in fungal sphingolipids. Minor differences observed in the ceramide moiety appeared to be strain‐dependent. More constant features of PLM from serotype B strains were the incorporation of greater amounts of phytosphingosine C20, a twofold reduced glycosylation of PLM and overexpression of a β‐1,2 mannotriose, the epitope of protective antibodies. This specific β‐mannosylation was observed even when growth conditions altered serotype A PPM‐specific epitopes, confirming the potential of PLM as a phenotypically stable molecule for serotyping. This study also suggests that the regulation of β‐mannosyltransferases, which define specific immunomodulatory adhesins whose activity depends on the mannosyl chain length, are part of the genetic background that differentiates serotypes.
Characterization of functional domains of the Vibrio cholerae virulence regulator ToxT
Authors: Prouty Michael G. , Osorio Carlos R. , Klose Karl E.
Published: October 2005

The toxT gene encodes an AraC family transcriptional activator that is responsible for regulating virulence gene expression in Vibrio cholerae. Analysis of ToxT by dominant/negative assays and a LexA‐based reporter system demonstrated that the N‐terminus of the protein contains dimerization determinants, indicating that ToxT likely functions as a dimer. Additionally, a natural variant of ToxT with only 60% identity in the N‐terminus, as well as a mutant form of ToxT with an altered amino acid in the N‐terminus (L107F), exhibited altered transcriptional responses to bile, suggesting that the N‐terminus is involved in environmental sensing. The C‐terminus of ToxT functions to bind DNA and requires dimerization for stable binding in vitro, as demonstrated by gel shift analysis. Interestingly, a dimerized form of the ToxT C‐terminus is able to bind DNA in vitro but is transcriptionally inactive in vivo, indicating that the N‐terminus contains determinants that are required for transcriptional activation. These results provide a model for a two‐domain structure for ToxT, with an N‐terminal dimerization and environmental sensing domain and a C‐terminal DNA‐binding domain; unlike other well‐studied AraC family proteins, both domains of ToxT appear to be required for transcriptional activation.
An Arabidopsis GRIP domain protein locates to the trans‐Golgi and binds the small GTPase ARL1
Authors: Latijnhouwers Maita , Hawes Chris , Carvalho Claudine , Oparka Karl , Gillingham Alison K. , Boevink Petra
Published: October 2005

GRIP domain proteins are a class of golgins that have been described in yeast and animals. They locate to the trans‐Golgi network and are thought to play a role in endosome‐to‐Golgi trafficking. The Arabidopsis GRIP domain protein, AtGRIP, fused to the green fluorescent protein (GFP), locates to Golgi stacks but does not exactly co‐locate with the Golgi marker sialyl transferase (ST)‐mRFP, nor with the t‐SNAREs Memb11, SYP31 and BS14a. We conclude that the location of AtGRIP is further to the trans side of the stack than STtmd–mRFP. The 185‐aa C‐terminus of AtGRIP containing the GRIP domain targeted GFP to the Golgi, although a proportion of the fusion protein was still found in the cytosol. Mutation of a conserved tyrosine (Y717) to alanine in the GRIP domain disrupted Golgi localization. ARL1 is a small GTPase required for Golgi targeting of GRIP domain proteins in other systems. An Arabidopsis ARL1 homologue was isolated and shown to target to Golgi stacks. The GDP‐restricted mutant of ARL1, AtARL1‐T31N, was observed to locate partially to the cytosol, whereas the GTP‐restricted mutant AtARL1‐Q71L labelled the Golgi and a population of small structures. Increasing the levels of AtARL1 in epidermal cells increased the proportion of GRIP–GFP fusion protein on Golgi stacks. We show, moreover, that AtARL1 interacted with the GRIP domain in a GTP‐dependent manner in vitro in affinity chromatography and in the yeast two‐hybrid system. This indicates that AtGRIP and AtARL1 interact directly. We conclude that the pathway involving ARL1 and GRIP domain golgins is conserved in plants.
DNA hypomethylation reduces homologous pairing of inserted tandem repeat arrays in somatic nuclei ofArabidopsis thaliana
Authors: Watanabe Koichi , Pecinka Ales , Meister Armin , Schubert Ingo , Lam Eric
Published: October 2005

Fluorescent chromatin tagging makes possible tracking of specific lociin vivoandin situ. Loci tagged by thelacoperator (lacO)/GFP‐LacI/Nuclear Localization Signal (NLS) system show rapid motility and constrained chromatin dynamics in somatic nuclei of a transgenic line, designated EL702C, inArabidopsis thaliana. The tagged loci associated with each other significantly more often than expected at random, due to homologous pairing of thelacOtandem repeat arrays. Furthermore, these arrays associated significantly more often than average euchromatic regions with heterochromatic chromocenters (CCs). We show now that the insertedlacOarray in this transgenic line became strongly methylated at CG sites in the T3 generation, which can be reversed upon transfer into the mutant backgrounds ofdecrease in DNA methylation 1(ddm1) andmethyltransferase 1(met1). Concomitantly, the tagged loci showed lower association frequencies as compared with the transgenics in wild‐type background, which is correlated with a significant decrease in allelic and ectopic pairing of thelacOrepeat arrays as visualized by fluorescencein situhybridization. In contrast, the preferential association of thelacOarrays with heterochromatin, locus mobility in somatic nuclei and transcription of neighboring transgenes were not altered by reduced DNA methylation inddm1andmet1backgrounds. Our results show that repeat arrays can activate hypermethylation of the inserted locus that correlates with high frequencies of homologous pairing in somatic cells. In contrast, the preferential association of these inserted arrays with CCs in plant cells occurs through another mechanism.
Characterization of an analphoid supernumerary marker chromosome derived from 15q25→qter using high‐resolution CGH and multiplex FISH analyses
Authors: Huang X‐L , De Michelena MI , Mark HFL , Harston R , Benke PJ , Price SJ , Milunsky A
Published: October 2005

Supernumerary marker chromosomes (SMCs) without detectable alphoid DNA are predicted to have a neocentromere and have been referred to as mitotically stable neocentromere marker chromosomes (NMCs). We report the molecular cytogenetic characterization of a new case with analphoid NMC derived from 15q25→qter using high‐resolution comparative genomic hybridization (HR‐CGH) and multiplex fluorescence in situ hybridization analyses with various α‐satellite DNA probes, all‐human‐centromere probe (AHC), whole chromosome painting probes, and a subtelomere probe. The propositus is a dysmorphic infant who, at age 3 months, showed accelerated growth, partial deafness, and a phenotype similar to that of the eight previously reported cases of distal 15q tetrasomy. Chromosome studies showed that he had a de novo extra SMC in 80% of cells examined. HR‐CGH revealed rev ish enh(15)(q25qter). Molecular cytogenetic analysis and molecular DNA polymorphism study demonstrated that this extra SMC is an NMC containing an inverted duplication of the distal long arm of chromosome 15 (tetrasomy 15q25→qter) which originated paternally, i.e. ish der(15)(qte→q25::q25[neocen]→qter)(AHC–, CEP15–, WCP15+, PCP15q++). This case further elucidates the phenotype related to tetrasomy of this specific chromosome segment and represents a new report of a neocentromere on distal chromosome 15q suggesting that this region appears to be susceptible to the formation of neocentromeres.
Frameshift and nonsense mutations in the gene for ATPase7B are associated with severe impairment of copper metabolism and with an early clinical manifestation of Wilson's disease
Authors: Gromadzka G. , Schmidt H.H.‐J. , Genschel J. , Bochow B. , Rodo M. , Tarnacka B. , Litwin T. , Chabik G. , Członkowska A.
Published: October 2005

Wilson's disease (WD) is an autosomal recessive disorder of copper metabolism. The clinical phenotype of the disease is varied. It is proposed that this variation may be a result of differential functional disruption of ATPase7B (ATP7B) resulting from mutations in the gene ATP7B. We aimed to assess the relationship between specific mutational defects in ATP7B and divergence in the phenotypic expression of WD. One hundred and forty‐two patients with clinically, biochemically and genetically diagnosed WD were included in the study. The phenotypic expression of WD was compared between patients with different types of mutations in ATP7B, detected by direct sequencing of exons 1–21 of the gene. Twenty‐six mutations were identified in ATP7B; eleven of them were mutations predicted to result in the absence of a full‐length normal protein [frameshift/nonsense mutations; classified as ‘severe’ mutations (SMs)], 14 were missense mutations (MMs) and one was a splice site mutation. Patients with one or two SMs on their alleles had lower serum copper and ceruloplasmin and were younger when the first symptoms of the disease appeared, compared with individuals with two MMs. The effect of SMs on the WD phenotype was dose‐dependent. It is concluded that mutations within ATP7B are very heterogeneous. Frameshift and nonsense mutations are associated with a severe phenotype of WD.
Pulmonary embolism caused by polymethylmethacrylate during percutaneous vertebroplasty in orthopaedic surgery
Authors: Freitag M. , Gottschalk A. , Schuster M. , Wenk W. , Wiesner L. , Standl T. G.
Published: October 2005

Vertebroplasty consists of percutaneous injection of acrylic cement ‐polymethylmethacrylate (PMMA)‐ into a partially collapsed vertebral body in order to obtain pain relief and augment mechanical stability of the vertebral body. Although vertebroplasty is an efficient treatment it is not free of complications. Our present case report describes a woman with pulmonary polymethylmethacrylate embolism during percutaneous vertebroplasty who presented with hypotension, arrhythmia and hypocapnia.
Cerebral microdialysis and Ptio2 for neuro‐monitoring before decompressive craniectomy
Authors: Boret H. , Fesselet J. , Meaudre E. , Gaillard P.‐E. , Cantais E.
Published: October 2005

We report the case of a young patient with post‐traumatic, intractable, intracranial hypertension leading to craniectomy. This intracranial hypertension was preceded by focal signs of ischemia diagnosed through Ptio2 monitoring and cerebral microdialysis, and occurred a few hours prior to a decrease in cerebral perfusion pressure below 60 mmHg. The neurological outcome was satisfactory with a Glasgow Outcome Scale of 4 at 3 months. We discuss the potential interest of such neuro‐monitoring to determine the optimal time for performing a craniectomy.