bluuebunny/crossref_metadata_2025 huggingface dataset:
Achieving epitaxy and intense luminescence in Ge∕Rb-implanted α-quartz
Authors: Sahoo P. K. , Gąsiorek S. , Lieb K. P. , Arstila K. , Keinonen J.
Published: July 2005

The luminescence properties of ion-beam doped silica and quartz depend sensitively on the ion species and fluence and the thermal processing during and after ion implantation. In an attempt to achieve high luminescence intensity and full planar recrystallization of α-quartz, we studied double Ge∕Rb-ion implantation, where the Rb ions serve as a catalyst only. Synthetic α-quartz samples were irradiated with 175 keV Rb ions and subsequently with 120 keV Ge ions with fluences of 1×1014–1×1016ions∕cm2 and postannealed at 1170 K in air. A comparative analysis of the epitaxy, migration of the implanted ions, and cathodoluminescence (CL) were carried out. The CL spectra exhibit three strong emission bands in the blue/violet range at 2.95, 3.25, and 3.53 eV, which were assigned to Rb- and/or Ge-related defect centers. For up to 1015 implanted Geions∕cm2, large fraction (75%) of the Ge atoms reach substitutional Si sites after the epitaxy.
Validation of the n-alkane technique for estimating diet composition, digestibility and dry matter intake in the brushtail possum (Trichosurus vulpecula)
Authors: Monks Adrian , Payton Ian , Efford Murray
Published: July 2005

Few validated studies have tested the n-alkane method for diet estimation in non-ruminants and the technique has rarely been validated for estimating diet composition for more than two dietary components. The arboreal marsupial Trichosurus vulpecula was fed leaf and fruit diets with up to five component species in two trials. In Trial 1, alkane recovery was estimated, and in Trial 2 these estimates were used to predict digestibility, diet composition and dry matter intake. Alkane recovery increased non-linearly (convex up) with increasing n-alkane chain length. Recovery was linearly and negatively correlated with diet digestibility and appeared to explain a progressive bias with observed digestibility in the alkane estimates of digestibility (slope = 0.37). Diet composition was successfully estimated for up to five leaf dietary components without correction for recovery. Correcting for recovery gave less reliable diet-composition predictions, indicating that the recovery estimates could not be extrapolated to the second trial. Dry matter intake appeared to be relatively robust to variation in alkane recovery between individuals (mean bias =1.6%). If recovery is shown to vary with digestibility in other taxa, calibration of the alkane technique will require diet- and taxon-specific calibration trials to give reliable estimates of diet composition and dry matter digestibility.
Wildlife management in Australasia: perceptions of objectives and priorities
Authors: Miller Kelly K. , Jones Darryl N.
Published: July 2005

The aim of this study was to examine the values and attitudes held by Australasian wildlife managers as they relate to wildlife management issues, and to gain some insight into possible future directions and priorities for Australasian wildlife management. During December 2002 – February 2003, 138 questionnaires were completed by members of the Australasian Wildlife Management Society (AWMS) and registrants of the 2002 AWMS annual conference. Threatened species management, threatened communities/habitats, and management of introduced species were the issues rated as needing the highest priority for the Australasian Wildlife Management Society. Issues such as animal rights, genetically modified organisms and timber harvesting on public lands were the lowest-rating issues. Respondents expressed a strong belief in managing and controlling wildlife to achieve wildlife management objectives, a strong belief that wildlife should be protected and that wildlife managers should minimise the pain and suffering of individual animals, and a belief that resources should be directed towards conserving wildlife populations rather than protecting individual animals from non-threatened populations. While respondents held a strong belief that it is important to consult the community when developing wildlife management policies and programs, there was little support for a comanagerial approach where the community has a significant role to play in decision-making processes.
Year-round presence of dugongs in Pumicestone Passage, south-east Queensland, examined in relation to water temperature and seagrass distribution
Authors: Lanyon Janet M. , Johns Trevor , Sneath Helen L.
Published: July 2005

Pumicestone Passage is a narrow waterway that lies to the north of and adjacent to Moreton Bay, and between mainland Queensland and Bribie Island, Australia. Anecdotal reports have suggested that the Passage is home to dugongs year-round despite winter water temperatures that are known to cause dugongs to migrate elsewhere. To examine the pattern of distribution and abundance of dugongs within the passage on a year-round basis, eight years of sightings data collected by a charter boat operator were examined. Dedicated aerial surveys of the passage were also conducted at two-monthly intervals over two years, and more intensively over a single winter. Dugong sightings were examined in relation to water temperatures and seagrass prevalence. The number of dugongs sighted in the area on any one survey varied from 0 to 13. Dugongs were seen in all months of the year and in each of the eight winters, indicating that Pumicestone Passage is used year-round despite winter water temperatures dropping to below 18°C from June to August inclusive and below 16°C in June. All dugong sightings occurred in the southern part of the passage, south of Tripcony Bight. Dugongs were associated with shallows that support Halophila and Halodule species of seagrass, food species that are favoured elsewhere in their range. The northern part of the passage also supports seagrasses that are eaten by dugongs and has water temperature ranges that are not appreciably different to those of the southern passage. However, the narrow channels and very shallow nature of the northern passage provides little to no deep-water refugia for dugongs and the seagrass beds are less extensive. This study suggests that southern Pumicestone Passage requires protection concomitant with it being a year-round refuge of the vulnerable dugong.
The sociogenetic structure of a controlled feral pig population
Authors: Spencer Peter B. S. , Lapidge Steve J. , Hampton Jordan O. , Pluske John R.
Published: July 2005

In Australia, the feral pig (Sus scrofa) is a significant vertebrate pest that has an impact on agricultural production, public health and ecosystem integrity. Although feral pigs are controlled throughout much of their range, little is known about the impact that these control programs have had on the social biology, structure and the dispersal of pigs. To begin to address this, we collected demographic data and genetic samples from 123 feral pigs culled during a regional aerial shooting program over 33 pastoral properties in the semi-arid rangelands of southern Queensland, Australia. Sampling was carried out after two years of extensive control efforts (aerial 1080-baiting) and the samples therefore represented a controlled, persecuted population with a bias towards young animals. The analysis of 13 microsatellite loci suggested that females will accept multiple matings, females form loose mobs that appear to be highly dynamic social groups, and males will travel large distances between mobs. These data indicate that feral pigs in this population had a high level of social contact and form a single open population with no evidence of genetic (population) structuring. Such information may be important to integrate into management strategies, particularly the development of contingency plans regarding the spread of wildlife diseases.
Population parameters and life-table analysis of two coexisting freshwater turtles: are the Bellinger River turtle populations threatened?
Authors: Blamires Sean J. , Spencer Ricky-John , King Peter , Thompson Michael B.
Published: July 2005

Two species of freshwater turtle coexist in the Bellinger River: Elseya georgesi is common but limited to the Bellinger River, whereas Emydura macquarii is widespread but rare in the Bellinger River. The Bellinger River population of E. macquarii has been proposed as a distinct subspecies, so it may be endangered. Survivorship, fecundity, growth, size and age were determined for El. georgesi and the finite rate of increase (λ) was estimated by a life-table analysis using mark–recapture data from surveys between 1988 and 2004. These parameters were compared with those of well studied populations of E. macquarii to assess whether modelling the demographic parameters of El. georgesi could serve as a surrogate for estimating the influences of these demographic parameters on λ in the Bellinger River population of E. macquarii. We estimated that ~4500 El. georgesi inhabit the study area and, despite a size distribution strongly biased towards large individuals, the population is increasing (λ = 1.15) in the best-case scenario, or slightly decreasing (λ = 0.96) in the worst-case scenario. Comparing El. georgesi with E. macquarii from the Bellinger River and elsewhere suggests that E. macquarii grows faster, attains greater maximum size, has a greater clutch size and a higher fecundity than El. georgesi. Hence, El. georgesi does not serve as a good surrogate to determine demographic influences on λ in E. macquarii.
Optimising the timing of visual surveys of crabeater seal abundance: haulout behaviour as a consideration
Authors: Southwell Colin
Published: July 2005

The most practical means of estimating pack-ice seal abundance is by conducting visual surveys from ships and aircraft. However, only those seals hauled out on the ice are ‘available’ to such surveys, and additional information on haulout behaviour is required to adjust counts of seals on the ice to estimate the total population size. Consideration of the optimal time to undertake visual surveys with respect to availability is important to ensure that bias and uncertainty in the abundance estimate are minimised for a fixed survey effort. In order to assess the optimal time for conducting visual surveys of crabeater seals (Lobodon carcinophaga), satellite-linked dive recorders were attached to 24 adult seals in the pack-ice off east Antarctica to record haulout behaviour over a 4-month period from mid-September to mid-January. The optimal time for visual surveys within these four months was December to mid-January (after the pupping season) when a high, relatively constant proportion of seals were hauled out over a period of 6–7 h during daylight, and when variation in haulout behaviour between seals was low. Despite the necessity for breeding seals to haul out continuously for extended periods during the pupping season, this was not a preferred time for visual surveys because variability in haulout behaviour between breeding and non-breeding seals was high. The efficiency of surveys before pupping was limited by the relatively short time during daylight when both the proportion of seals hauled out was high and variability in haulout behaviour among seals was small.
Feral pigs in north-western Australia: basic biology, bait consumption, and the efficacy of 1080 baits
Authors: Twigg Laurie E. , Lowe Tim , Martin Gary , Everett Michael
Published: July 2005

Bait consumption, and the efficacy of 1080-treated grain, were determined for feral pigs (Sus scrofa) during the dry season in the Fitzroy River region of north-western Australia. There were an estimated 250 pigs on the study site (15 000-ha paddock with beef cattle) before poison-baiting, and group size and the basic biology of these pigs were similar to that found elsewhere in Australia. All animals at the study site were naive to the test baits. Fermented wheat with added blood and bone was an attractant for feral pigs but added fish oil was not. Wheat and malted barley were the ‘preferred’ baits. Lupins and pig pellets were consumed in lesser amounts, suggesting that they are less/not acceptable to some feral pigs. Consequently, the efficacy of 1080-treated wheat and malted barley was determined (n = 3 sites per treatment). Three independent measures of pig activity/abundance were used. The daily sighting index before and after poison-baiting suggested that pig numbers were decreased by at least 81–100% (mean 89%) regardless of which bait was used. The take of both 1080-bait and non-toxic fermented wheat added to each station generally ceased within 1–3 days, and little take occurred during the post-poisoning follow-up. Pig tracks decreased to zero within 1–3 days of poisoning on the two sites where track plots were established. However, due to the arrival of ‘immigrant’ pigs ~6 days after poisoning on two sites, and the need to close down a third site before poison-baiting could be completed, we believe the absolute efficacy was greater than the 89% overall reduction. Even though they had access to bait, there was no bait-take by non-target species, either native (toxic and non-toxic bait) or domestic (non-toxic bait). The 61 pig carcases found after poisoning were within 20–610 m of active bait stations (mean 232 m), and most were found in clustered groups. These findings are discussed with respect to the development of management strategies for reducing the impacts of feral pigs, and in terms of their potential implications for developing wildlife disease (exotic and endemic) contingency plans.
Cell-based cancer gene therapy: breaking tolerance or inducing autoimmunity?
Authors: Rodriguez-Lecompte Juan Carlos , Kruth Steve , Gyorffy Steve , Wan Yong-Hong , Gauldie Jack
Published: July 2005

This review examines the mechanisms involved in anti-tumor immunity and how peptides present in many tumor types (tumor-associated antigens) are recognized by T cells from tumor-bearing cancer patients. Tumor-associated antigens are derived from proteins that are also expressed in normal cells. It is predicted that immune responses to such peptides will be compromised by self-tolerance or that stimulation of effective immune responses will be accompanied by autoimmunity. We also consider that the immunity induced against two autoantigens, which are highly conserved in vertebrates, involve qualitatively different mechanisms, such as the production of antibodies and cell-mediated immune responses. However, both pathways lead to tumor immunity and identical phenotypic manifestations of autoimmunity. Appropriate selection of the optimal tumor antigen is critical for the induction of an anti-tumor immune response. Thus, we stress that the methods for antigen presentation using dendritic cells play a critical role in the development of tumor vaccines, to break immune tolerance and induce a strong immune response against them. The viability and feasibility of expansion of canine dendritic cells from bone marrow and peripheral blood ex vivo for the treatment of spontaneous cancers in dogs is also discussed.
The design of randomized controlled trials of veterinary vaccines
Authors: Dohoo Ian R.
Published: July 2005

Randomized controlled trials of veterinary vaccines are essential if we are to have a reasonable understanding of how those vaccines can be expected to perform when used in the field. This manuscript reviews a few (but certainly not all) of the key elements that need to be considered in the design of veterinary vaccine trials. The first step in the design of such a trial is to have a clear statement of the objective of the trial that reflects what is expected of the vaccine (e.g. should it minimize clinical disease or does it need to prevent infection?). Because domestic animals are often managed in groups, the ‘unit of concern’ used in a vaccine trial becomes of great importance. Whether the trial should be carried out at the individual or group level will depend on the objectives of the trial and the extent of concern about ‘group effects’ affecting the trial. Sample sizes will also be influenced heavily by the choice of unit of concern and the nature of the primary outcome being assessed. Finally, while there is no easy solution (except to conduct group-level trials, which may be logistically impossible), the potential for group effects to influence the trial outcome must be considered.
Microarrays in veterinary diagnostics
Authors: Feilotter Harriet E.
Published: July 2005

Microarrays have numerous applications in the clinical setting, and these uses are not confined to the study of common human diseases. Indeed, the high-throughput technology affects clinical diagnostics in a variety of contexts, and this is reflected in the increasing use of microarray-based tools in the development of diagnostic and prognostic tests and in the identification of novel therapeutic targets. While much of the value of microarray-based experimentation has been derived from the study of human disease, there is equivalent potential for its role in veterinary medicine. Even though the resources devoted to the study of animal molecular diagnostics may be less than those available for human research, there is nonetheless a growing appreciation of the value of genome-wide information as it applies to animal disease. Therefore, this review focuses on the basics of microarray experimentation, and how this technology lends itself to a variety of diagnostic approaches in veterinary medicine.
Challenges confronting feline vaccination
Authors: Richards James R.
Published: July 2005

Vaccination continues to be a major tool for controlling feline infectious diseases, but numerous factors present both challenges and opportunities for maintaining and expanding the market for veterinary biologicals. Developing novel vaccines is one approach, but in most cases the market for such products will be restricted to niche populations; the comparatively smaller quantity of vaccines sold may be offset somewhat if available from a limited number of manufacturers. A second approach is to produce better formulations of existing vaccines; such products would be applicable to larger populations of cats and have greater sales potential. But veterinarians must be convinced of the improved product's superiority for it to be successful in the marketplace. To ensure that high-quality, useful and necessary vaccines reach the marketplace, communication between veterinarians, the manufacturers of biologicals, and regulatory agencies must be enhanced.
The impact of vaccines and the future of genetically modified poxvirus vaccines for poultry
Authors: Tripathy Deoki N.
Published: July 2005

The regular use of live or killed vaccines against infectious agents has remarkably improved the efficiency of poultry production. In some cases eradication of disease has been possible when the pathogen is antigenically stable and confined to a certain geographical area. In other instances monovalent or polyvalent live or killed vaccines have been effective in reducing mortality and morbidity. Many conventional vaccines are developed by trial and error and basic information about their genetic make-up is not known. While the poultry industry has benefited from the regular use of conventional vaccines, there is need for a new generation of effective vaccines that require minimal handling of birds during administration. Using molecular techniques, it is possible to identify the genes associated with virulence and protection. In genetically engineered vaccines, genes that encode protective antigens can be expressed in bacterial or viral vectors. In this regard, avianpox virus vectors appear to be promising for the generation of polyvalent vaccines expressing antigens from multiple pathogens.
Aberrant lysosomal carbohydrate storage accompanies endocytic defects and neurodegeneration inDrosophila benchwarmer
Authors: Dermaut Bart , Norga Koenraad K. , Kania Artur , Verstreken Patrik , Pan Hongling , Zhou Yi , Callaerts Patrick , Bellen Hugo J.
Published: July 2005

Lysosomal storage is the most common cause of neurodegenerative brain disease in preadulthood. However, the underlying cellular mechanisms that lead to neuronal dysfunction are unknown. Here, we report that loss of Drosophila benchwarmer (bnch), a predicted lysosomal sugar carrier, leads to carbohydrate storage in yolk spheres during oogenesis and results in widespread accumulation of enlarged lysosomal and late endosomal inclusions. At the bnch larval neuromuscular junction, we observe similar inclusions and find defects in synaptic vesicle recycling at the level of endocytosis. In addition, loss of bnch slows endosome-to-lysosome trafficking in larval garland cells. In adultbnch flies, we observe age-dependent synaptic dysfunction and neuronal degeneration. Finally, we find that loss of bnch strongly enhances tau neurotoxicity in a dose-dependent manner. We hypothesize that, in bnch, defective lysosomal carbohydrate efflux leads to endocytic defects with functional consequences in synaptic strength, neuronal viability, and tau neurotoxicity.
A microtubule-dependent zone of active RhoA during cleavage plane specification
Authors: Bement William M. , Benink Hélène A. , von Dassow George
Published: July 2005

Cytokinesis in animal cells results from the assembly and constriction of a circumferential array of actin filaments and myosin-2. Microtubules of the mitotic apparatus determine the position at which the cytokinetic actomyosin array forms, but the molecular mechanisms by which they do so remain unknown. The small GTPase RhoA has previously been implicated in cytokinesis. Using four-dimensional microscopy and a probe for active RhoA, we show that active RhoA concentrates in a precisely bounded zone before cytokinesis and is independent of actin assembly. Cytokinetic RhoA activity zones are common to four echinoderm species, the vertebrate Xenopus laevis, and the highly asymmetric cytokinesis accompanying meiosis. Microtubules direct the formation and placement of the RhoA activity zone, and the zone is repositioned after physical spindle displacement. We conclude that microtubules specify the cytokinetic apparatus via a dynamic zone of local RhoA activity.
Dissociation of Akt1 from its negative regulator JIP1 is mediated through the ASK1–MEK–JNK signal transduction pathway during metabolic oxidative stress
Authors: Song Jae J. , Lee Yong J.
Published: July 2005

We have previously observed that metabolic oxidative stress–induced death domain–associated protein (Daxx) trafficking is mediated by the ASK1–SEK1–JNK1–HIPK1 signal transduction pathway. The relocalized Daxx from the nucleus to the cytoplasm during glucose deprivation participates in a positive regulatory feedback loop by binding to apoptosis signal–regulating kinase (ASK) 1. In this study, we report that Akt1 is involved in a negative regulatory feedback loop during glucose deprivation. Akt1 interacts with c-Jun NH2-terminal kinase (JNK)–interacting protein (JIP) 1, and Akt1 catalytic activity is inhibited. The JNK2-mediated phosphorylation of JIP1 results in the dissociation of Akt1 from JIP1 and subsequently restores Akt1 enzyme activity. Concomitantly, Akt1 interacts with stress-activated protein kinase/extracellular signal–regulated kinase (SEK) 1 (also known as MKK4) and inhibits SEK1 activity. Knockdown of SEK1 leads to the inhibition of JNK activation, JIP1–JNK2 binding, and the dissociation of Akt1 from JIP1 during glucose deprivation. Knockdown of JIP1 also leads to the inhibition of JNK activation, whereas the knockdown of Akt1 promotes JNK activation during glucose deprivation. Altogether, our data demonstrate that Akt1 participates in a negative regulatory feedback loop by interacting with the JIP1 scaffold protein.
Membrane recruitment of NOD2 in intestinal epithelial cells is essential for nuclear factor–κB activation in muramyl dipeptide recognition
Authors: Barnich Nicolas , Aguirre Jose E. , Reinecker Hans-Christian , Xavier Ramnik , Podolsky Daniel K.
Published: July 2005

Nucleotide oligomerization domain (NOD) 2 functions as a mammalian cytosolic pathogen recognition molecule, and mutant forms have been genetically linked to Crohn's disease (CD). NOD2 associates with the caspase activation and recruitment domain of RIP-like interacting caspase-like apoptosis regulatory protein kinase (RICK)/RIP2 and activates nuclear factor (NF)–κB in epithelial cells and macrophages, whereas NOD2 mutant 3020insC, which is associated with CD, shows an impaired ability to activate NF-κB. To gain insight into the molecular mechanisms of NOD2 function, we performed a functional analysis of deletion and substitution NOD2 mutants. NOD2, but not NOD2 3020insC mutant, associated with cell surface membranes of intestinal epithelial cells. Membrane targeting and subsequent NF-κB activation are mediated by two leucine residues and a tryptophan-containing motif in the COOH-terminal domain of NOD2. The membrane targeting of NOD2 is required for NF-κB activation after the recognition of bacterial muramyl dipeptide in intestinal epithelial cells.
Proteomic analysis of a eukaryotic cilium
Authors: Pazour Gregory J. , Agrin Nathan , Leszyk John , Witman George B.
Published: July 2005

Cilia and flagella are widespread cell organelles that have been highly conserved throughout evolution and play important roles in motility, sensory perception, and the life cycles of eukaryotes ranging from protists to humans. Despite the ubiquity and importance of these organelles, their composition is not well known. Here we use mass spectrometry to identify proteins in purified flagella from the green alga Chlamydomonas reinhardtii. 360 proteins were identified with high confidence, and 292 more with moderate confidence. 97 out of 101 previously known flagellar proteins were found, indicating that this is a very complete dataset. The flagellar proteome is rich in motor and signal transduction components, and contains numerous proteins with homologues associated with diseases such as cystic kidney disease, male sterility, and hydrocephalus in humans and model vertebrates. The flagellum also contains many proteins that are conserved in humans but have not been previously characterized in any organism. The results indicate that flagella are far more complex than previously estimated.
Inhibition of astroglial nuclear factor κB reduces inflammation and improves functional recovery after spinal cord injury
Authors: Brambilla Roberta , Bracchi-Ricard Valerie , Hu Wen-Hui , Frydel Beata , Bramwell Annmarie , Karmally Shaffiat , Green Edward J. , Bethea John R.
Published: July 2005

In the central nervous system (CNS), the transcription factor nuclear factor (NF)-κB is a key regulator of inflammation and secondary injury processes. After trauma or disease, the expression of NF-κB–dependent genes is highly activated, leading to both protective and detrimental effects on CNS recovery. We demonstrate that selective inactivation of astroglial NF-κB in transgenic mice expressing a dominant negative (dn) form of the inhibitor of κBα under the control of an astrocyte-specific promoter (glial fibrillary acidic protein [GFAP]–dn mice) leads to a dramatic improvement in functional recovery 8 wk after contusive spinal cord injury (SCI). Histologically, GFAP mice exhibit reduced lesion volume and substantially increased white matter preservation. In parallel, they show reduced expression of proinflammatory chemokines and cytokines, such as CXCL10, CCL2, and transforming growth factor–β2, and of chondroitin sulfate proteoglycans participating in the formation of the glial scar. We conclude that selective inhibition of NF-κB signaling in astrocytes results in protective effects after SCI and propose the NF-κB pathway as a possible new target for the development of therapeutic strategies for the treatment of SCI.
BLT1-mediated T cell trafficking is critical for rejection and obliterative bronchiolitis after lung transplantation
Authors: Medoff Benjamin D. , Seung Edward , Wain John C. , Means Terry K. , Campanella Gabriele S.V. , Islam Sabina A. , Thomas Seddon Y. , Ginns Leo C. , Grabie Nir , Lichtman Andrew H. , Tager Andrew M. , Luster Andrew D.
Published: July 2005

Leukotriene B4 is a lipid mediator that recently has been shown to have potent chemotactic activity for effector T lymphocytes mediated through its receptor, BLT1. Here, we developed a novel murine model of acute lung rejection to demonstrate that BLT1 controls effector CD8+ T cell trafficking into the lung and that disruption of BLT1 signaling in CD8+ T cells reduces lung inflammation and mortality in the model. In addition, we used BLT1-deficient mice and a BLT1 antagonist in two tracheal transplant models of lung transplantation to demonstrate the importance of BLT1 for the recruitment of T cells into tracheal allografts. We also show that BLT1-mediated CD8+ T cell recruitment plays an important role in the development of airway fibroproliferation and obliteration. Finally, in human studies of lung transplant recipients, we found that BLT1 is up-regulated on T lymphocytes isolated from the airways of patients with obliterative bronchiolitis. These data demonstrate that BLT1 contributes to the development of lung rejection and obliterative bronchiolitis by mediating effector T lymphocyte trafficking into the lung. This is the first report that describes a pathologic role for BLT1-mediated T lymphocyte recruitment in disease and identifies BLT1 as a potential therapeutic target after lung transplantation.
The timing of TCRα expression critically influences T cell development and selection
Authors: Baldwin Troy A. , Sandau Michelle M. , Jameson Stephen C. , Hogquist Kristin A.
Published: July 2005

Sequential rearrangement of the T cell receptor for antigen (TCR) β and α chains is a hallmark of thymocyte development. This temporal control is lost in TCR transgenics because the α chain is expressed prematurely at the CD4−CD8− double negative (DN) stage. To test the importance of this, we expressed the HYα chain at the physiological CD4+CD8+ double positive (DP) stage. The reduced DP and increased DN cellularity typically seen in TCR transgenics was not observed when the α chain was expressed at the appropriate stage. Surprisingly, antigen-driven selection events were also altered. In male mice, thymocyte deletion now occurred at the single positive or medullary stage. In addition, no expansion of CD8αα intestinal intraepithelial lymphocytes (IELs) was observed, despite the fact that HY transgenics have been used to model IEL development. Collectively, these data establish the importance of proper timing of TCR expression in thymic development and selection and emphasize the need to use models that most accurately reflect the physiologic process.
Regulation of natural cytotoxicity by the adaptor SAP and the Src-related kinase Fyn
Authors: Bloch-Queyrat Coralie , Fondanèche Marie-Claude , Chen Riyan , Yin Luo , Relouzat Francis , Veillette André , Fischer Alain , Latour Sylvain
Published: July 2005

SAP is an adaptor protein that is expressed in NK and T cells. It is mutated in humans who have X-linked lymphoproliferative (XLP) disease. By interacting with SLAM family receptors, SAP enables tyrosine phosphorylation signaling of these receptors by its ability to recruit the Src-related kinase, Fyn. Here, we analyzed the role of SAP in NK cell functions using the SAP-deficient mouse model. Our results showed that SAP was required for the ability of NK cells to eliminate tumor cells in vitro and in vivo. This effect strongly correlated with expression of CD48 on tumor cells, the ligand of 2B4, a SLAM-related receptor expressed in NK cells. In keeping with earlier reports that studied human NK cells, we showed that SAP was necessary for the ability of 2B4 to trigger cytotoxicity and IFN-γ secretion. In the absence of SAP, 2B4 function was shifted toward inhibition of NK cell–mediated cytotoxicity. By analyzing mice lacking Fyn, we showed that similarly to SAP, Fyn was strictly required for 2B4 function. Taken together, these results provide evidence that the 2B4-SAP-Fyn cascade defines a potent activating pathway of natural cytotoxicity. They also could help to explain the high propensity of patients who have XLP disease to develop lymphoproliferative disorders.
Plasmacytoid predendritic cells initiate psoriasis through interferon-α production
Authors: Nestle Frank O. , Conrad Curdin , Tun-Kyi Adrian , Homey Bernhard , Gombert Michael , Boyman Onur , Burg Günter , Liu Yong-Jun , Gilliet Michel
Published: July 2005

Psoriasis is one of the most common T cell–mediated autoimmune diseases in humans. Although a role for the innate immune system in driving the autoimmune T cell cascade has been proposed, its nature remains elusive. We show that plasmacytoid predendritic cells (PDCs), the natural interferon (IFN)-α–producing cells, infiltrate the skin of psoriatic patients and become activated to produce IFN-α early during disease formation. In a xenograft model of human psoriasis, we demonstrate that blocking IFN-α signaling or inhibiting the ability of PDCs to produce IFN-α prevented the T cell–dependent development of psoriasis. Furthermore, IFN-α reconstitution experiments demonstrated that PDC-derived IFN-α is essential to drive the development of psoriasis in vivo. These findings uncover a novel innate immune pathway for triggering a common human autoimmune disease and suggest that PDCs and PDC-derived IFN-α represent potential early targets for the treatment of psoriasis.
Disruption of Nrf2 enhances susceptibility to severe airway inflammation and asthma in mice
Authors: Rangasamy Tirumalai , Guo Jia , Mitzner Wayne A. , Roman Jessica , Singh Anju , Fryer Allison D. , Yamamoto Masayuki , Kensler Thomas W. , Tuder Rubin M. , Georas Steve N. , Biswal Shyam
Published: July 2005

Oxidative stress has been postulated to play an important role in the pathogenesis of asthma; although a defect in antioxidant responses has been speculated to exacerbate asthma severity, this has been difficult to demonstrate with certainty. Nuclear erythroid 2 p45-related factor 2 (Nrf2) is a redox-sensitive basic leucine zipper transcription factor that is involved in the transcriptional regulation of many antioxidant genes. We show that disruption of the Nrf2 gene leads to severe allergen-driven airway inflammation and hyperresponsiveness in mice. Enhanced asthmatic response as a result of ovalbumin sensitization and challenge in Nrf2-disrupted mice was associated with more pronounced mucus cell hyperplasia and infiltration of eosinophils into the lungs than seen in wild-type littermates. Nrf2 disruption resulted in an increased expression of the T helper type 2 cytokines interleukin (IL)-4 and IL-13 in bronchoalveolar lavage fluid and in splenocytes after allergen challenge. The enhanced severity of the asthmatic response from disruption of the Nrf2 pathway was a result of a lowered antioxidant status of the lungs caused by lower basal expression, as well as marked attenuation, of the transcriptional induction of multiple antioxidant genes. Our studies suggest that the responsiveness of Nrf2-directed antioxidant pathways may act as a major determinant of susceptibility to allergen-mediated asthma.
Dendritic cells star in Vancouver
Authors: Klechevsky Eynav , Kato Hiroki , Sponaas Anne-Marit
Published: July 2005

The fast-moving field of dendritic cell (DC) biology is hard to keep pace with. Here we report on advances from the recent Keystone Symposium, “Dendritic Cells at the Center of Innate and Adaptive Immunity,” organized in Vancouver, BC on Feb. 1–7, 2005 by Anne O'Garra, Jacques Banchereau, and Alan Sher. New insights into the molecular mechanisms of DC function and their influence on immune regulation, their role in infectious and autoimmune disease, and new clinical applications are highlighted.
A Romani mitochondrial haplotype in England 500 years before their recorded arrival in Britain
Authors: Töpf Ana L , Hoelzel A. Rus
Published: July 2005

The nomadic Romani (gypsy) people are known for their deep-rooted traditions, but most of their history is recorded from external sources. We find evidence for a Romani genetic lineage in England long before their recorded arrival there. The most likely explanations are that either the historical record is wrong, or that early liaisons between Norse and Romani people during their coincident presence in ninth to tenth century Byzantium led to the spread of the haplotype to England.
A cryptic taxon of Galápagos tortoise in conservation peril
Authors: Russello Michael A , Glaberman Scott , Gibbs James P , Marquez Cruz , Powell Jeffrey R , Caccone Adalgisa
Published: July 2005

As once boldly stated, ‘bad taxonomy can kill’, highlighting the critical importance of accurate taxonomy for the conservation of endangered taxa. The concept continues to evolve almost 15 years later largely because most legal protections aimed at preserving biological diversity are based on formal taxonomic designations. In this paper we report unrecognized genetic divisions within the giant tortoises of the Galápagos. We found three distinct lineages among populations formerly considered a single taxon on the most populous and accessible island of Santa Cruz; their diagnosability, degree of genetic divergence and phylogenetic placement merit the recognition of at least one new taxon. These results demonstrate the fundamental importance of continuing taxonomic investigations to recognize biological diversity and designate units of conservation, even within long-studied organisms such as Galápagos tortoises, whose evolutionary heritage and contribution to human intellectual history warrant them special attention.
Eating without hands or tongue: specialization, elaboration and the evolution of prey processing mechanisms in cartilaginous fishes
Authors: Dean Mason N , Wilga Cheryl D , Summers Adam P
Published: July 2005

The ability to separate edible from inedible portions of prey is integral to feeding. However, this is typically overlooked in favour of prey capture as a driving force in the evolution of vertebrate feeding mechanisms. In processing prey, cartilaginous fishes appear handicapped because they lack the pharyngeal jaws of most bony fishes and the muscular tongue and forelimbs of most tetrapods. We argue that the elaborate cranial muscles of some cartilaginous fishes allow complex prey processing in addition to their usual roles in prey capture. The ability to manipulate prey has evolved twice along different mechanical pathways. Batoid chondrichthyans (rays and relatives) use elaborate lower jaw muscles to process armored benthic prey, separating out energetically useless material. In contrast, megacarnivorous carcharhiniform and lamniform sharks use a diversity of upper jaw muscles to control the jaws while gouging, allowing for reduction of prey much larger than the gape. We suggest experimental methods to test these hypotheses empirically.
An Opial-type inequality with an integral boundary condition
Authors: Brown Richard C , Plum Michael
Published: July 2005

We determine the best constant
K
and extremals of the Opial-type inequality

, where
y
is required to satisfy the boundary condition

. The techniques employed differ from those utilized recently by Denzler to solve this problem, and also from those used originally to prove the classical inequality; but they also yield a new proof of that inequality.
mSin3A corepressor regulates diverse transcriptional networks governing normal and neoplastic growth and survival
Authors: Dannenberg Jan-Hermen , David Gregory , Zhong Sheng , van der Torre Jaco , Wong Wing H. , DePinho Ronald A.
Published: July 2005

mSin3A is a core component of a large multiprotein corepressor complex with associated histone deacetylase (HDAC) enzymatic activity. Physical interactions of mSin3A with many sequence-specific transcription factors has linked the mSin3A corepressor complex to the regulation of diverse signaling pathways and associated biological processes. To dissect the complex nature of mSin3A's actions, we monitored the impact of conditional mSin3A deletion on the developmental, cell biological, and transcriptional levels. mSin3A was shown to play an essential role in early embryonic development and in the proliferation and survival of primary, immortalized, and transformed cells. Genetic and biochemical analyses established a role for mSin3A/HDAC in p53 deacetylation and activation, although genetic deletion of p53 was not sufficient to attenuate the mSin3A null cell lethal phenotype. Consistent with mSin3A's broad biological activities beyond regulation of the p53 pathway, time-course gene expression profiling following mSin3A deletion revealed deregulation of genes involved in cell cycle regulation, DNA replication, DNA repair, apoptosis, chromatin modifications, and mitochondrial metabolism. Computational analysis of the mSin3A transcriptome using a knowledge-based database revealed several nodal points through which mSin3A influences gene expression, including the Myc-Mad, E2F, and p53 transcriptional networks. Further validation of these nodes derived from in silico promoter analysis showing enrichment for Myc-Mad, E2F, and p53 cis-regulatory elements in regulatory regions of up-regulated genes following mSin3A depletion. Significantly, in silico promoter analyses also revealed specific cis-regulatory elements binding the transcriptional activator Stat and the ISWI ATP-dependent nucleosome remodeling factor Falz, thereby expanding further the mSin3A network of regulatory factors. Together, these integrated genetic, biochemical, and computational studies demonstrate the involvement of mSin3A in the regulation of diverse pathways governing many aspects of normal and neoplastic growth and survival and provide an experimental framework for the analysis of essential genes with diverse biological functions.
CTD-dependent dismantling of the RNA polymerase II elongation complex by the pre-mRNA 3′-end processing factor, Pcf11
Authors: Zhang Zhiqiang , Fu Jianhua , Gilmour David S.
Published: July 2005

Pcf11 is one of numerous proteins involved in pre-mRNA 3′-end processing and transcription termination. Using elongation complexes (ECs) formed from purified yeast RNA polymerase II (Pol II), we show that a 140-amino acid polypeptide from yeast Pcf11 is capable of dismantling the EC in vitro. This action depends on the C-terminal domain (CTD) of the largest subunit of Pol II and the CTD-interaction domain (CID) of Pcf11. Our experiments reveal a novel termination mechanism whereby Pcf11 bridges the CTD to the nascent transcript and causes dissociation of both Pol II and the nascent transcript from the DNA in the absence of nucleotide hydrolysis. We posit that conformational changes in the CTD are transduced through Pcf11 to the nascent transcript to cause termination.
VEGF–PLCγ1 pathway controls cardiac contractility in the embryonic heart
Authors: Rottbauer Wolfgang , Just Steffen , Wessels Georgia , Trano Nicole , Most Patrick , Katus Hugo A. , Fishman Mark C.
Published: July 2005

The strength of the heart beat can accommodate in seconds to changes in blood pressure or flow. The mechanism for such homeostatic adaptation is unknown. We sought the cause of poor contractility in the heart of the embryonic zebrafish with the mutation dead beat. We find through cloning that this is due to a mutation in the phospholipase C γ1 (plcγ1) gene. In mutant embryos, contractile function can be restored by PLCγ1 expression directed selectively to cardiac myocytes. In other situations, PLCγ1 is known to transduce the signal from vascular endothelial growth factor (VEGF), and we show here that abrogation of VEGF also interferes with cardiac contractility. Somewhat unexpectedly, FLT-1 is the responsible VEGF receptor. We show that the same system functions in the rat. Blockage of VEGF–PLCγ1 signaling decreases calcium transients in rat ventricular cardiomyocytes, whereas VEGF imposes a positive inotropic effect on cardiomyocytes by increasing calcium transients. Thus, the muscle of the heart uses the VEGF–PLCγ1 cascade to control the strength of the heart beat. We speculate that this paracrine system may contribute to normal and pathological regulation of cardiac contractility.
Identification of a motif that mediates polypyrimidine tract-binding protein-dependent internal ribosome entry
Authors: Mitchell Sally A. , Spriggs Keith A. , Bushell Martin , Evans Joanne R. , Stoneley Mark , Le Quesne John P.C. , Spriggs Ruth V. , Willis Anne E.
Published: July 2005

We have identified a novel motif which consists of the sequence (CCU)nas part of a polypyrimidine-rich tract and permits internal ribosome entry. A number of constructs containing variations of this motif were generated and these were found to function as artificial internal ribosome entry segments (AIRESs) in vivo and in vitro in the presence of polypyrimidine tract-binding protein (PTB). The data show that for these sequences to function as IRESs the RNA must be present as a double-stranded stem and, in agreement with this, rather surprisingly, we show that PTB binds strongly to double-stranded RNA. All the cellular 5′ untranslated regions (UTRs) tested that harbor this sequence were shown to contain internal ribosome entry segments that are dependent upon PTB for function in vivo and in vitro. This therefore raises the possibility that PTB or its interacting protein partners could provide a bridge between the IRES-RNA and the ribosome. Given the number of putative cellular IRESs that could be dependent on PTB for function, these data strongly suggest that PTB-1 is a universal IRES-trans-acting factor.
Mutation scanning by meltMADGE: Validations usingBRCA1andLDLR, and demonstration of the potential to identify severe, moderate, silent, rare, and paucimorphic mutations in the general population
Authors: Alharbi Khalid K. , Aldahmesh Mohammed A. , Spanakis Emmanuel , Haddad Lema , Whittall Roslyn A. , Chen Xiao-he , Rassoulian Hamid , Smith Matt J. , Sillibourne Julie , Ball Nicola J. , Graham Nikki J. , Briggs Patricia J. , Simpson Iain A. , Phillips David I.W. , Lawlor Deborah A. , Ye Shu , Humphries Stephen E. , Cooper Cyrus , Smith George Davey , Ebrahim Shah , Eccles Diana M. , Day Ian N.M.
Published: July 2005

We have developed a mutation-scanning approach suitable for whole population screening for unknown mutations. The method, meltMADGE, combines thermal ramp electrophoresis with MADGE to achieve suitable cost efficiency and throughput. The sensitivity was tested in blind trials using 54 amplicons representing theBRCA1coding region and a panel of 94 unrelated family breast cancer risk consultands previously screened in a clinical diagnostic laboratory. All 10 common polymorphisms, 15/15 previously identified disease-causing mutations, and three previously untested single base changes were identified. Assays ofLDLRexons 3 and 8 were validated in 460 familial hypercholesteremics and detected 8/9 known variants. We then applied the exon 3 assay in several DNA banks representing ∼8000 subjects with known cholesterol values and applied both assays in one DNA bank (n= 3600). In exon 3 we identified one previously reported moderate mutation, P84S (n= 1), also associated with moderate hypercholesteremia in this subject; an unreported silent variant, N76N (n= 1); and known severe hypercholesteremia splice mutation 313+1G→A (n= 2). Around exon 8 we identified a paucimorphism (n= 35) at the splice site 1061–8T→C (known to be in complete linkage disequilibrium with T705I) and unreported sequence variants 1186+11G→A (n= 1) and D335N G→A (n= 1). The cholesterol value for D335N was on the 96.2 percentile and for T705I, 2/35 carriers were above the 99th percentile. Thus, variants with predicted severe, moderate, and no effect were identified at the population level. In contrast with case collections, CpG mutations predominated. MeltMADGE will enable definition of the full population spectrum of rare, paucimorphic, severe, moderate (forme fruste), and silent mutations and effects.