bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural characterization of copper(II) binding to α-synuclein: Insights into the bioinorganic chemistry of Parkinson's disease
Authors: Rasia Rodolfo M. , Bertoncini Carlos W. , Marsh Derek , Hoyer Wolfgang , Cherny Dmitry , Zweckstetter Markus , Griesinger Christian , Jovin Thomas M. , Fernández Claudio O.
Published: March 2005

The aggregation of α-synuclein (AS) is characteristic of Parkinson's disease and other neurodegenerative synucleinopathies. We demonstrate here that Cu(II) ions are effective in accelerating AS aggregation at physiologically relevant concentrations without altering the resultant fibrillar structures. By using numerous spectroscopic techniques (absorption, CD, EPR, and NMR), we have located the primary binding for Cu(II) to a specific site in the N terminus, involving His-50 as the anchoring residue and other nitrogen/oxygen donor atoms in a square planar or distorted tetragonal geometry. The carboxylate-rich C terminus, originally thought to drive copper binding, is able to coordinate a second Cu(II) equivalent, albeit with a 300-fold reduced affinity. The NMR analysis of AS–Cu(II) complexes reveals the existence of conformational restrictions in the native state of the protein. The metallobiology of Cu(II) in Parkinson's disease is discussed by a comparative analysis with other Cu(II)-binding proteins involved in neurodegenerative disorders.
Introduction: Italy in the EU—pigmy or giant?
Authors: Fabbrini Sergio , Piattoni Simona
Published: March 2005

This introductory article discusses the circumstances under which Italy manages to forge ‘national preferences’ and push them through the European policy-making process. Drawing from the analysis of several policy areas, it concludes that Italy plays a major policy-making role, particularly when it acts as mediator between large countries and small- and medium-sized ones, and when it argues its case according to policy- and EU-appropriate logics. While Italy may not have it ‘its way’ all the time (as no member-state does), it still manages to influence the EU policy-making process more frequently and more significantly than the literature has so far conceded.
Activity-dependent and -independent nuclear fluxes of HDAC4 mediated by different kinases in adult skeletal muscle
Authors: Liu Yewei , Randall William R. , Schneider Martin F.
Published: March 2005

Class II histone deacetylases (HDACs) may decrease slow muscle fiber gene expression by repressing myogenic transcription factor myocyte enhancer factor 2 (MEF2). Here, we show that repetitive slow fiber type electrical stimulation, but not fast fiber type stimulation, caused HDAC4-GFP, but not HDAC5-GFP, to translocate from the nucleus to the cytoplasm in cultured adult skeletal muscle fibers. HDAC4-GFP translocation was blocked by calmodulin-dependent protein kinase (CaMK) inhibitor KN-62. Slow fiber type stimulation increased MEF2 transcriptional activity, nuclear Ca2+ concentration, and nuclear levels of activated CaMKII, but not total nuclear CaMKII or CaM-YFP. Thus, calcium transients for slow, but not fast, fiber stimulation patterns appear to provide sufficient Ca2+-dependent activation of nuclear CaMKII to result in net nuclear efflux of HDAC4. Nucleocytoplasmic shuttling of HDAC4-GFP in unstimulated resting fibers was not altered by KN-62, but was blocked by staurosporine, indicating that different kinases underlie nuclear efflux of HDAC4 in resting and stimulated muscle fibers.
β-site specific intrabodies to decrease and prevent generation of Alzheimer's Aβ peptide
Authors: Paganetti Paolo , Calanca Verena , Galli Carmela , Stefani Muriel , Molinari Maurizio
Published: March 2005

Endoproteolysis of the β-amyloid precursor protein (APP) by β- and γ-secretases generates the toxic amyloid β-peptide (Aβ), which accumulates in the brain of Alzheimer's disease (AD) patients. Here, we established a novel approach to regulate production of Aβ based on intracellular expression of single chain antibodies (intrabodies) raised to an epitope adjacent to the β-secretase cleavage site of human APP. The intrabodies rapidly associated, within the endoplasmic reticulum (ER), with newly synthesized APP. One intrabody remained associated during APP transport along the secretory line, shielded the β-secretase cleavage site and facilitated the alternative, innocuous cleavage operated by α-secretase. Another killer intrabody with an ER retention sequence triggered APP disposal from the ER. The first intrabody drastically inhibited and the second almost abolished generation of Aβ. Intrabodies association with specific substrates rather than with enzymes, may modulate intracellular processes linked to disease with highest specificity and may become instrumental to investigate molecular mechanisms of cellular events.
Vaccinia virus protein A46R targets multiple Toll-like–interleukin-1 receptor adaptors and contributes to virulence
Authors: Stack Julianne , Haga Ismar R. , Schröder Martina , Bartlett Nathan W. , Maloney Geraldine , Reading Patrick C. , Fitzgerald Katherine A. , Smith Geoffrey L. , Bowie Andrew G.
Published: March 2005

Viral immune evasion strategies target key aspects of the host antiviral response. Recently, it has been recognized that Toll-like receptors (TLRs) have a role in innate defense against viruses. Here, we define the function of the vaccinia virus (VV) protein A46R and show it inhibits intracellular signalling by a range of TLRs. TLR signalling is triggered by homotypic interactions between the Toll-like–interleukin-1 resistance (TIR) domains of the receptors and adaptor molecules. A46R contains a TIR domain and is the only viral TIR domain–containing protein identified to date. We demonstrate that A46R targets the host TIR adaptors myeloid differentiation factor 88 (MyD88), MyD88 adaptor-like, TIR domain–containing adaptor inducing IFN-β (TRIF), and the TRIF-related adaptor molecule and thereby interferes with downstream activation of mitogen-activated protein kinases and nuclear factor κB. TRIF mediates activation of interferon (IFN) regulatory factor 3 (IRF3) and induction of IFN-β by TLR3 and TLR4 and suppresses VV replication in macrophages. Here, A46R disrupted TRIF-induced IRF3 activation and induction of the TRIF-dependent gene regulated on activation, normal T cell expressed and secreted. Furthermore, we show that A46R is functionally distinct from another described VV TLR inhibitor, A52R. Importantly, VV lacking the A46R gene was attenuated in a murine intranasal model, demonstrating the importance of A46R for VV virulence.
Regulation of anaphylactic responses by phosphatidylinositol phosphate kinase type I α
Authors: Sasaki Junko , Sasaki Takehiko , Yamazaki Masakazu , Matsuoka Kunie , Taya Choji , Shitara Hiroshi , Takasuga Shunsuke , Nishio Miki , Mizuno Katsunori , Wada Teiji , Miyazaki Hideyuki , Watanabe Hiroshi , Iizuka Ryota , Kubo Shuichi , Murata Shigeo , Chiba Tomoki , Maehama Tomohiko , Hamada Koichi , Kishimoto Hiroyuki , Frohman Michael A. , Tanaka Keiji , Penninger Josef M. , Yonekawa Hiromichi , Suzuki Akira , Kanaho Yasunori
Published: March 2005

The membrane phospholipid phosphatidylinositol 4, 5-bisphosphate [PI(4,5)P2] is a critical signal transducer in eukaryotic cells. However, the physiological roles of the type I phosphatidylinositol phosphate kinases (PIPKIs) that synthesize PI(4,5)P2 are largely unknown. Here, we show that the α isozyme of PIPKI (PIPKIα) negatively regulates mast cell functions and anaphylactic responses. In vitro, PIPKIα-deficient mast cells exhibited increased degranulation and cytokine production after Fcε receptor-I cross-linking. In vivo, PIPKIα−/− mice displayed enhanced passive cutaneous and systemic anaphylaxis. Filamentous actin was diminished in PIPKIα−/− mast cells, and enhanced degranulation observed in the absence of PIPKIα was also seen in wild-type mast cells treated with latrunculin, a pharmacological inhibitor of actin polymerization. Moreover, the association of FcεRI with lipid rafts and FcεRI-mediated activation of signaling proteins was augmented in PIPKIα−/− mast cells. Thus, PIPKIα is a negative regulator of FcεRI-mediated cellular responses and anaphylaxis, which functions by controlling the actin cytoskeleton and dynamics of FcεRI signaling. Our results indicate that the different PIPKI isoforms might be functionally specialized.
Interleukin-1 receptor-associated kinase-1 plays an essential role for Toll-like receptor (TLR)7- and TLR9-mediated interferon-α induction
Authors: Uematsu Satoshi , Sato Shintaro , Yamamoto Masahiro , Hirotani Tomonori , Kato Hiroki , Takeshita Fumihiko , Matsuda Michiyuki , Coban Cevayir , Ishii Ken J. , Kawai Taro , Takeuchi Osamu , Akira Shizuo
Published: March 2005

Toll-like receptors (TLRs) recognize microbial pathogens and trigger innate immune responses. Among TLR family members, TLR7, TLR8, and TLR9 induce interferon (IFN)-α in plasmacytoid dendritic cells (pDCs). This induction requires the formation of a complex consisting of the adaptor MyD88, tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) and IFN regulatory factor (IRF) 7. Here we show an essential role of IL-1 receptor-associated kinase (IRAK)-1 in TLR7- and TLR9-mediated IRF7 signaling pathway. IRAK-1 directly bound and phosphorylated IRF7 in vitro. The kinase activity of IRAK-1 was necessary for transcriptional activation of IRF7. TLR7- and TLR9-mediated IFN-α production was abolished in Irak-1–deficient mice, whereas inflammatory cytokine production was not impaired. Despite normal activation of NF-κB and mitogen-activated protein kinases, IRF7 was not activated by a TLR9 ligand in Irak-1–deficient pDCs. These results indicated that IRAK-1 is a specific regulator for TLR7- and TLR9-mediated IFN-α induction in pDCs.
Comparative evaluation of three different ELISA methods for the diagnosis of early culture-confirmed Lyme disease in Italy
Authors: Marangoni Antonella , Sparacino Monica , Cavrini Francesca , Storni Elisa , Mondardini Valeria , Sambri Vittorio , Cevenini Roberto
Published: March 2005

In this study the raising and development of the immune response to Borrelia burgdorferi infection in 45 Italian patients suffering from culture-confirmed Lyme borreliosis erythema migrans was investigated. A total of 95 serially collected serum samples were tested by using three different commercial ELISAs: recomWell Borrelia (Mikrogen), Enzygnost Borreliosis (DADE Behring) and Quick ELISA C6 Borrelia (Immunetics). The sensitivities of the ELISAs were as follows: Enzygnost Borreliosis IgM, 70.5 %; Quick ELISA C6 Borrelia, 62.1 %; recomWell Borrelia IgM, 55.7 %; recomWell Borrelia IgG, 57.9 %; and Enzygnost Borreliosis IgG, 36.8 %. In order to compare the specificity values of the three ELISAs, a panel of sera obtained from blood donors (210 samples coming from a non-endemic area and 24 samples from an endemic area) was tested, as well as sera from patients suffering from some of the most common biological conditions that could result in false-positive reactivity in Lyme disease serology (n = 40). RecomWell Borrelia IgG and recomWell Borrelia IgM were the most specific (97.1 % and 98.9 %, respectively), followed by Quick ELISA C6 Borrelia (96.7 %). Enzygnost Borreliosis IgG and IgM achieved 90.1 % and 92.3 % specificity, respectively. Sera that gave discrepant results when tested by the three ELISAs were further analysed by Western blotting.
Superantigen genes encoded by the egc cluster and SaPIbov are predominant among Staphylococcus aureus isolates from cows, goats, sheep, rabbits and poultry
Authors: Smyth Davida S , Hartigan Patrick J , Meaney William J , Fitzgerald J Ross , Deobald Claudia F , Bohach Gregory A , Smyth Cyril J
Published: March 2005

In recent years several new staphylococcal enterotoxins (SEs) have been described, which currently have largely unknown frequencies of occurrence and roles in human or animal disease. One hundred and ninety-one Staphylococcus aureus isolates from cows (99), goats (39), sheep (23), rabbits (15), chickens (15) and a cat (1) were screened for SE genes sea–see, seg–seo and seq and for the tst gene encoding staphylococcal toxic shock syndrome toxin-1 using multiplex PCRs and individual PCRs for the seb and sek genes. One hundred and ten isolates tested positive for at least one of these 16 superantigen (SAg)-encoding genes. There were statistically significant differences in the frequencies of some of these SAg genes between isolates from different animals. No strain possessed either the sea or see gene. The sec gene was present in 51 isolates, the sed gene in eight and the seb gene in one. The seh gene was found in four strains and the sek and seq genes together in one isolate. The most common combinations of genes were the egc cluster, bearing the seg, sei, sem, sen and seo genes, in 47 isolates, the sec, sel and tst gene combination typical of the SaPIbov pathogenicity island in 44 isolates, the egc cluster lacking the seg gene in 11 isolates, the sed and sej genes in nine isolates, and the sec and tst genes without the sel gene in seven isolates. The higher frequencies of the sec and tst genes together and the lower frequencies of the egc gene cluster among the SAg gene-positive sheep or goat isolates compared to bovine isolates were statistically significant. Of 36 bovine isolates that were mitogenic for human T lymphocytes, four were negative for the 16 SAg genes tested for, while a further 14 gave borderline results in the mitogenicity assay, 12 of which were SAg gene-negative. Twenty-nine strains lacking all the SAg genes did not induce T-cell proliferation. This survey indicates that novel SE genes seg, sei, sel, sem, sen and seo along with the sec and tst genes predominate in S. aureus from animal hosts. The mitogenicity assays indicate that further uncharacterized SAgs may be present in bovine isolates.
Community-acquired pneumonia in Japan: a prospective ambulatory and hospitalized patient study
Authors: Miyashita Naoyuki , Fukano Hiroshi , Mouri Keiji , Fukuda Minoru , Yoshida Koichiro , Kobashi Yoshihiro , Niki Yoshihito , Oka Mikio
Published: March 2005

In this study the aetiology of community-acquired pneumonia (CAP) in Japan was investigated and the incidence of causative pathogens in ambulatory and hospitalized patients was compared. In addition, the roles ofChlamydophila felisandChlamydophila pecorumas causes of CAP were investigated. Five hundred and six patients with CAP who visited an outpatient clinic or were admitted to one of three different hospitals were enrolled in this study; 106 of them were outpatients and 400 were hospitalized patients. Among the 506 CAP cases,Mycoplasma pneumoniaewas the most common pathogen found in the outpatients andStreptococcus pneumoniaewas the most common in the hospitalized patients. No cases ofChlamydophila pecorumpneumonia were observed and only one patient had an antibody titre suggestive of recent infection with the feline strain ofChlamydophila. The incidence of infection withM. pneumoniaeandChlamydophila pneumoniaewas higher among the outpatients than among hospitalized patients, whereas the incidence of infection withS. pneumoniaeandHaemophilus influenzaewas higher among the hospitalized patients. Recognition of these results will allow prompt and appropriate antimicrobial therapy to be provided using Japanese CAP guidelines.
Regulation of neuron survival and death by p130 and associated chromatin modifiers
Authors: Liu David X. , Nath Niharika , Chellappan Srikumar P. , Greene Lloyd A.
Published: March 2005

E2F-mediated gene repression plays a key role in regulation of neuron survival and death. However, the key molecules involved in such regulation and the mechanisms by which they respond to apoptotic stimuli are largely unknown. Here we show that p130 is the predominant Rb family member associated with E2F in neurons, that its major partner for repression of pro-apoptotic genes is E2F4, and that the p130-E2F4 complex recruits the chromatin modifiers HDAC1 and Suv39H1 to promote gene silencing and neuron survival. Apoptotic stimuli induce neuron death by sequentially causing p130 hyperphosphorylation, dissociation of p130-E2F4-Suv39H1-HDAC complexes, altered modification of H3 histone and gene derepression. Experimental suppression of such events blocks neuron death while interference with the synthesis of E2F4 or p130, or with the interaction of E2F4-p130 with chromatin modifiers, induces neuron death. Thus, neuron survival and death are dependent on the integrity of E2F4-p130-HDAC/Suv39H1 complexes.
Cancer-associated mutations in chromatin remodeler hSNF5 promote chromosomal instability by compromising the mitotic checkpoint
Authors: Vries Robert G.J. , Bezrookove Vladimir , Zuijderduijn Lobke M.P. , Kia Sima Kheradmand , Houweling Ada , Oruetxebarria Igor , Raap Anton K. , Verrijzer C. Peter
Published: March 2005

The hSNF5 subunit of human SWI/SNF ATP-dependent chromatin remodeling complexes is a tumor suppressor that is inactivated in malignant rhabdoid tumors (MRTs). Here, we report that loss of hSNF5 function in MRT-derived cells leads to polyploidization and chromosomal instability. Re-expression of hSNF5 restored the coupling between cell cycle progression and ploidy checkpoints. In contrast, cancer-associated hSNF5 mutants harboring specific single amino acid substitutions exacerbated poly- and aneuploidization, due to abrogated chromosome segregation. We found that hSNF5 activates the mitotic checkpoint through the p16INK4a-cyclinD/CDK4-pRb-E2F pathway. These results establish that poly- and aneuploidy of tumor cells can result from mutations in a chromatin remodeler.
Personal home pages as a resource
Authors: Narsesian Shant , Nicholas David
Published: March 2005

Purpose

To help determine the extent to which “unique” informational content is available on personal home pages (PHP) on the world wide web (WWW).

Design/methodology/approach

The informational content of PHPs is manually compared with the informational content of non‐PHPs in the field of professional football in England. This produces instances of information which is available on the PHPs but not on the non‐PHPs. A search is then carried out to determine whether these pieces of information are available elsewhere on the web.

Findings

There are notable quantities of information which are only available on PHPs. There are also instances where certain information will be available on PHPs before it is available on non‐PHPs. In addition, the degree to which information on PHPs is correct is also likely to be quite high. These facts in conjunction suggest that PHPs as a whole make a notable contribution to the informational content of the WWW.

Research limitations/implications

The sample data are limited in size and scope.

Practical implications

PHP visibility and utilization may increase.

Originality/value

Provides a methodology for informational comparisons of web pages.
Impact of the internet on delivery of reference services in English public libraries
Authors: Jay Margaret , Webber Sheila
Published: March 2005

Purpose

Aims to investigate the impact of the internet on reference services in public libraries in England.

Design/methodology/approach

A literature review provides the policy context for UK public library services and highlights developments in digital reference. A questionnaire was administered in 2003 to a sample of the public library authorities in England, investigating the use of the internet for receiving or answering reference enquiries, the use of electronic reference sources, and the nature of public library web sites.

Findings

Thirty responses were received, representing a response rate of 60 per cent. All respondents used e‐mail to answer reference enquiries, but there was low use (and in some cases awareness) of other technologies. The librarians' attitude towards digital reference services, considering aspects such as improved access and increased efficiency, was predominantly positive. Some concerns were raised, such as the administration of public access computers. Patrons could access more electronic reference sources within the library than they could remotely. The majority of public libraries had web sites, most commonly offering access to the library catalogue and community databases. The results of this study are compared with two previous surveys.

Practical implications

The paper concludes by identifying the need for public library managers to assess the changing role of professionals and para‐professionals in delivering reference services, and to provide appropriate training. It also notes that despite the discussion of real‐time reference, asynchronous digital reference is still more common in England.

Originality/value

There has not been a survey of this type for English public library authorities. The sample represents 20 per cent of the target population.
DELIVERing library resources to the virtual learning environment
Authors: Secker Jane
Published: March 2005

Purpose

Examines a project to integrate digital libraries and virtual learning environments (VLE) focusing on requirements for online reading list systems.

Design/methodology/approach

Conducted a user needs analysis using interviews and focus groups and evaluated three reading or resource list management systems.

Findings

Provides a technical specification for an online reading list system, subsequent work to develop a rights management system and a “library area” within the VLE where electronic resources can be placed. Discusses other relevant developments towards the integration of digital libraries and virtual learning environments, including the IMS specification for Resource List Interoperability (RLI).

Research limitations/implications

Results could be compared to findings from other institutions. The evaluation work could be brought up to date with new developments in the two commercial reading list systems.

Practical implications

Provides an evaluation of three reading list management systems including TalisList, Sentient Discover and an open source solution, Bookworm.

Originality/value

Practical information of value to learning technologists and librarians, recognising the importance of presenting library resources in the VLE in a systematic way.
Production of ceramic additive automotive brake lining and investigation of its braking characterisation
Authors: Mutlu I. , Eldogan O. , Findik F.
Published: March 2005

Purpose

The aim of the research is to investigate the ceramic brake lining on the brake performance.Design/methodology/approach– The brake lining which has new formulation has been produced by using various additive materials. Various techniques have been used in the production of brake lining. These ceramic linings were subjected to friction and wear tests under different loads, and changes in the hardness and microstructures were examined.Findings– As a result of this study, the following findings are reported. A direct proportional was not found between hardness and wear resistance due to the complexity of composite structure. Kevlar fibers were homogeneously distributed in the matrix and therefore, very few microvoids were observed in the structure. Similarly, stone wool was well spread out the braking pad and hence decreased the microvoids' occurrence. Heat treatment supplied more homogeneous structure and hence, microstructural variations were minimised during the brake action. On the other hand, heat treatment decreased the hardness of glass fiber reinforced specimens and increased the density. Each specimen was affected from the environmental conditions. However, water affected all specimens more than the other environmental conditions, such as salty water, oil and braking liquid. With the increasing of temperature, the ingredients in the braking pad were affected other due to better diffusion. On the other hand, hardness of specimens increases and density decreases due to heat treatment and also specific wear ratio changes.Research limitations/implications– Limitations in the present research are as follows: two different pressures and eight different temperatures were used and brake linings were subjected to wear test, hardness tests, microstructures were examined.Practical implications– For future work, instead of buying expensive brake lining, new and cheaper ceramic linings are produced. By this process, economic benefit can be gained and also environmental protection can be succeeded in producing such asbestos free brake linings.Originality/value– This paper fulfills an identified information and offers practical help to the industrial firms working with brake lining and also to the academicians working on wear of materials.
Desirable search features of web‐based scholarly e‐book systems
Authors: Su Shiao‐Feng
Published: March 2005

Purpose

To examine what search capabilities are desirable in web‐based scholarly e‐book systems.

Design/methodology/approach

To present the author's opinion and interpretation about what search capabilities are desirable in web‐based scholarly e‐book systems through investigating studies of information seeking behavior and exploring current multimedia and hypertext techniques.

Findings

The findings are several desirable browsing and known‐item search features of web‐based scholarly e‐book systems.

Originality/value

The author's suggestion on the implementation of a dedicated, user‐oriented and user‐friendly interface, which includes the search features recommended in this paper to unleash the power of multimedia and hyperlinks.
The evolving Information Commons
Authors: Church Jennifer
Published: March 2005

Purpose

To examine the changing nature and adaptation of the Information Commons concept at the University of Nevada, Las Vegas.

Design/methodology/approach

This article is primarily a case study on the growth and development of technology at Lied Library, including its expansion beyond the physical confines of the original model of the Information Commons. Additionally, a cross‐section of articles regarding the principles of providing services and systems within an Information Commons is surveyed.

Findings

Stresses the importance of maintaining a flexible model for the integration of technology and library services.

Practical implications

A matter‐of‐fact source for the implications of rethinking and reinventing the Information Commons concept.

Originality/value

This article addresses considerations important to the integration and evolution of technology services and space within academic libraries.
A volunteer companion‐observer intervention reduces falls on an acute aged care ward
Authors: Donoghue Judith , Graham Jenny , Mitten‐Lewis Suzanne , Murphy Moira , Gibbs Julie
Published: March 2005

Purpose

Falls are the most frequently reported adverse event in hospitalised patients and carry a risk of great harm for the frail elderly. This intervention aimed to prevent high‐risk in‐patients on an acute aged care ward from falling.

Design/methodology/approach

Patients assessed at high falls risk were accommodated in a room staffed by volunteer companion‐observers. The volunteers engaged them in conversation, played cards, opened meals and used the call bell to summon nurses if patients attempted to move from the bed or chair without assistance. Because of occupational health and safety considerations, the volunteers did not assist patients to ambulate.

Findings

The falls rate in the acute aged care ward decreased by 44 percent (p<0.000). No patients fell in the observation room when volunteers were present. Relatives of participating in‐patients expressed appreciation of the volunteer role, in terms of increased safety and also companionship. Volunteers exercised initiative in determining their pattern of work and developing resources to support their role.

Research limitations/implications

Because volunteers are not present around the clock, other strategies are needed to prevent wandering, frequently confused older in‐patients from falling during the night.

Practical implications

In a context where frail elderly patients need constant supervision, using volunteers is a reasonable strategy.

Originality/value

This intervention used an inexpensive, human resources‐based approach to significantly reduce the incidence of falls in the population at highest risk of falling. The additional benefits to patients in terms of cognitive improvement bear further investigation.
The relationship between fish species richness, abundance and habitat complexity in a range of shallow tropical marine habitats
Authors: Gratwicke B. , Speight M. R.
Published: March 2005

A simple habitat assessment score (HAS) was designed to assess habitat complexity across several different shallow tropical marine habitats including sandy patches, algal beds, seagrass beds and reefs. It measured rugosity, variety of growth forms, height, refuge size categories, percentage live cover and percentage hard substratum. Multiple regression models using HAS variables as predictors accounted for 71 and 22% of the variation in observed species richness and total fish abundance respectively. The two most important predictors of observed species richness were rugosity and variety of growth forms, while height was the most important predictor of total fish abundance. The HAS method worked consistently across a variety of habitat types and the complexity map closely mirrored the map of observed species richness, reflecting the patchy habitat mosaic of shallow tropical marine areas. Stations at the mouth of an enclosed lagoon, however, had a higher number of species than might have been expected judging from the habitat complexity scores. It is possible that this was linked to the preferential settling of pelagic fish larvae in this area as tidal water exchanges between the bay and the reef were funnelled through one small gap. This study highlights the need for fish biodiversity studies to take habitat complexity into account.
Feeding ecology of silver hake larvae on the Western Bank, Scotian Shelf, and comparison with Atlantic Cod
Authors: Reiss C. , McLaren I. , Avendaño P. , Taggart C.
Published: March 2005

The feeding ecology of the larvae of silver hake Merluccius bilinearis was examined during two time periods (October 1998 and December 1992) on the Western Bank, Scotian Shelf, north‐west Atlantic, and compared with the feeding ecology of Atlantic cod Gadus morhua larvae collected in the same samples in December 1992. During both time periods silver hake exhibited strong selection for late stage copepodids and adult copepods at a small size (>3·5 mm total length, LT). The niche width measured as the diet breadth index (IDB) of silver hake declined rapidly as they increased in size and remained relatively constant from 3 to 11 mm LT, during each time period. Atlantic cod larvae exhibited a broader niche width that was curvilinear over the same LT. Atlantic cod were also less selective than silver hake, incorporating both naupliar and early stage copepodids in their diets throughout the length classes examined. Simple isometric relationships did not explain the differences in diet, as Atlantic cod larvae continued to feed on early stages of copepods at large size, while silver hake larvae quickly switched to large prey items. The strong selection and narrow IDB observed for silver hake probably reflects adaptation to spawning during the periods between major secondary production peaks in temperate waters.
Growth variation in larval Makaira nigricans
Authors: Sponaugle S. , Denit K. L. , Luthy S. A. , Serafy J. E. , Cowen R. K.
Published: March 2005

The Atlantic blue marlin Makaira nigricans larvae were collected from Exuma Sound, Bahamas and the Straits of Florida over three summers (2000–2002). Sagittal otoliths were extracted and read under light microscopy to determine relationships between standard length (LS) and age for larvae from each year and location. Otolith growth trajectories were significantly different between locations: after the first 5–6 days of life, larvae from Exuma Sound grew significantly faster than larvae from the Straits of Florida. Exponential regression coefficients were similar among years for Exuma Sound larvae (mean instantaneous growth rate, GL = 0·125), but differed between years for larvae from the Straits of Florida (GL = 0·086–0·089). Differences in larval growth rates between locations resulted in a 4–6 mm difference in LS by day 15 of larval life. These differences in growth appeared to be unrelated to mean ambient water temperatures, and may have been caused by location‐specific differences in prey composition or availability. Alternatively, population‐specific differences in maternal condition may have contributed to these differences in early larval growth.
Quantifying root lateral distribution and turnover using pine trees with a distinct stable carbon isotope signature
Authors: JOHNSEN K. , MAIER C. , KRESS L.
Published: March 2005

In order to help assess spatial competition for below‐ground resources, we quantified the effects of fertilization on root biomass quantity and lateral root distribution of mid‐rotationPinus taedatrees. Open‐top chambers exposed trees to ambient or ambient plus 200 µmol mol−1atmospheric CO2for 31 months.

Tank CO2was depleted in atmospheric13C; foliage of elevated CO2trees had δ13C of −42·9, compared with −29·1 for ambient CO2trees.

Roots 1 m from the base of elevated CO2‐grown trees had more negative δ13C relative to control trees, and this difference was detected, on average, up to 5·8, 3·7 and 3·7 m away from the trees for 0–2, 2–5 and >5 mm root‐size classes, respectively. Non‐fertilized tree roots extended as far as fertilized trees despite the fact that their above‐ground biomass was less than half that of fertilized trees.

These results are informative with respect to root sampling intensity and protocol, and the distances required between experimental manipulations to evaluate below‐ground processes of independent treatments.

Fine‐root turnover has usually been estimated to range from weeks to 3 years, representing a major avenue of carbon flux. Using a mixing model we calculated that 0–2 mm roots had a mean residence time of 4·5 years indicating relatively slow fine‐root turnover, a result that has major implications in modelling C cycling.
Invasion in grassland gaps: the role of neighbourhood richness, light availability and species complementarity during two successive years
Authors: MILBAU A. , NIJS I. , DE RAEDEMAECKER F. , REHEUL D. , DE CAUWER B.
Published: March 2005

We examined how the performance of three grass species, inserted as invaders in the gaps of synthesized communities, was affected by percentage light transmittance in these gaps and by the species richness and productivity of the surrounding neighbour plants. We also investigated whether these influences changed through time.

In both the first and the second season following invader establishment, realized growth (invader leaf length) was positively related to percentage light transmittance (which was the best predictor for invasibility), and negatively related to neighbour biomass, in all species examined. The richness–invasibility relationship became significant only in year 2, when increasing neighbourhood richness enhanced complementarity (demonstrated by means ofImax, an index for assessing the degree of complementary resource use), which in turn negatively affected invader leaf length. In the first year such a relationship had not yet developed, probably because the communities were still young and plant interactions were still limited. However, even in year 2 the richness effect saturated at low richness, with no mixture over‐yielding the best two‐species mixture.

The data suggest that moderately productive, species‐rich communities, preferably with some broad‐leaved species, and with a nutrient input as low as possible, will offer the best defence against invasions.
Interaction between organ mass and citrate synthase activity as an indicator of tissue maximal oxidative capacity in breeding European Starlings: implications for metabolic rate and organ mass relationships
Authors: VÉZINA F. , WILLIAMS T. D.
Published: March 2005

Numerous studies have suggested that basal metabolic rate (BMR) is related to variation in mass of specific ‘energy‐expensive’ organs such as heart and kidney.

However, there are inconsistencies among studies with regard to those organs that show positive relationships with BMR, potentially because such studies assume constant organ metabolic intensity or capacity (e.g. oxidative activity).

This paper investigates metabolic adjustments (citrate synthase activity) in four key organs (pectoral muscle, heart, kidney and liver) in free‐living reproductive female European Starlings (Sturnus vulgaris) throughout the breeding season to determine if the cost of egg production results in readjustments in organ mass‐specific enzyme activity.

Citrate synthase (CS) activity varied in relation to breeding stage and/or year, but this variation was not consistent among different organs. For some organs, total enzymatic activity was directly related to changes in organ mass in relation to breeding stage. For others, increased organ mass was associated with a decrease in mass‐specific CS activity, resulting in no net change in total organ oxidative capacity among breeding stages.

Even though the liver is actively involved in yolk precursor production during egg formation, no evidence was found for up‐regulation of mass‐specific oxidative enzyme activity in this organ.

Metabolic adjustments at the organ level may occur independently from organ mass changes and this confounding effect may be responsible for part of the inconsistencies found between previous studies in terms of organs mass–RMR relationships.
The paradox of the weakening combatant: trade‐off between closing force and gripping speed in a sexually selected combat structure
Authors: LEVINTON J. S. , ALLEN B. J.
Published: March 2005

Previous evidence demonstrates that closing force decreases proportionally as fiddler crab claw size increases. Larger crabs do have greater absolute closing force, but less than would be expected if claw proportions were isometric. In the Mud Fiddler Crab, Uca pugnax, this is explained by a decrease in mechanical advantage with increasing claw size.

We here re‐measure mechanical advantage with a more direct method than used previously; the relationship of mechanical advantage to claw size was similar to the older indirect measure. Because the fiddler crab claw is a simple lever, we predicted that the observed decline in closing force should be compensated by a proportional increase in closing speed.

We tested this hypothesis using high‐speed video to observe crabs closing their major claws spontaneously under controlled conditions. Closing speed scaled positively to claw length as predicted, and the value of the exponent conformed to expectation from a simple biomechanical model.

Evolution of the fiddler crab claw therefore involved a trade‐off of closing force for closing speed. An adaptive explanation of relative weakening with increasing body size may lie in the increased ability to rapidly grasp an opponent, a crucial advantage in fiddler crab combat.
Apparent fragility of African hair is unrelated to the cystine‐rich protein distribution: a cytochemical electron microscopic study
Authors: Khumalo N. P. , Dawber R. P. R. , Ferguson D. J. P.
Published: March 2005

Abstract:  A feature of black African hair is an apparent increased fragility of the hair shaft compared to other ethnic groups (as measured by the tensile force needed to break the hair fibre). This has certain similarities to that reported for trichorrhexis nodosa (weathering secondary to physical damage) and trichothiodystrophy [a genetic disorder associated with reduced cystine (sulphur)‐rich proteins and increased fragility]. In the present study, the distribution of the cystine‐rich proteins in the hair of black Africans was compared to that of Caucasian and Asian volunteers, plus patients with trichorrhexis nodosa and trichothiodystrophy, using transmission electron microscopy and specific silver stains. It was found that the silver staining pattern of the hair shafts of black Africans was similar to that observed for Caucasians, Asians and also patients with trichorrhexis nodosa. The cuticular cells exhibited an electron dense A layer and exocuticle, and in the cortex the microfibrils forming the macrofibres were outlined by electron‐dense material. This contrasts with the abnormal distribution of the cystine‐rich proteins seen in trichothiodystrophy. This study is the first formal comparison of the cystine‐rich proteins in the various racial groups and shows that there is no abnormality in their distribution in black African hair shafts compared to the other ethnic groups. Therefore, the excessive structural damage observed in the African hair shafts is consistent with physical trauma (resulting from grooming) rather than an inherent weakness due to any structural abnormality.
Identification and expression profiling of a human C‐type lectin, structurally homologous to mouse dectin‐2
Authors: Gavino Alde Carlo P. , Chung Jin‐Sung , Sato Kota , Ariizumi Kiyoshi , Cruz Ponciano D.
Published: March 2005

Abstract:  A number of C‐type lectins on antigen‐presenting cells play an important role in regulating innate immunity. Previously, we identified the mouse C‐type lectins (dectin‐1, and dectin‐2) and human DECTIN‐1. To identify human DECTIN‐2, we employed degenerative polymerase chain reaction‐based cDNA cloning using RNA from human Langerhans cell (LC)‐like dendritic cells (DCs). This process yielded a cDNA encoding a C‐type lectin with 66.5% amino acid sequence homology to mouse dectin‐2, the same gene reported by Kanazawa et al. (J Invest Dermatol 2004: 122: 1522–1524) using the disparate approach of analyzing coding sequences in chromosome 12. Similar to their findings, we found gene expression in lung, spleen, and lymph node. Among resting leukocytes, it was expressed at highest levels by CD14+ monocytes, at lower levels by CD19+ B cells, and not at all by CD4+ T cells. Activation of CD19+ B cells with pokeweed mitogen down‐regulated gene expression, whereas expression in CD4+ T cells was induced by Con A. Among our novel findings are an alternatively spliced transcript lacking exon 2, expression in bone marrow and tonsil, expression in CD8+ T cells that is abrogated following activation with phytohemagglutinin, restricted expression to CD1a+ LC within epidermis, and preferential expression by plasmacytoid (rather than myeloid) DC. Finally, we found that treatment with interleukin‐4 (IL‐4), IL‐10, or UVB down regulated gene expression in CD14+ monocytes, whereas granulocyte‐macrophage colony‐stimulating factor, transforming growth factor‐β1, or tumor necrosis factor‐α treatment up‐regulated it. Our findings may form the basis for understanding the function of human DECTIN‐2 in innate immunity.
Progress in epidermolysis bullosa: the phenotypic spectrum of plectin mutations
Authors: Pfendner E. , Rouan F. , Uitto J.
Published: March 2005

Abstract:  Plectin, a large multidomain adhesive protein with versatile binding functions, is expressed in a number of tissues and cell types. In the skin, plectin is a critical component of hemidesmosomes, interacting with keratin intermediate filaments and β4 integrin. Mutations in the plectin gene (PLEC1) result in fragility of skin, demonstrating blister formation at the level of hemidesmosomes. These blistering disorders belong to the spectrum of epidermolysis bullosa (EB) phenotypes, and three distinct variants because of plectin mutations have been identified. First, EB with muscular dystrophy, an autosomal recessive syndrome, is frequently caused by premature termination codon‐causing mutations leading to the absence of plectin both in the skin and in the muscle. Second, a heterozygous missense mutation (R2110W) in PLEC1 has been documented in patients with EB simplex of the Ogna type, a rare autosomal dominant disorder. Finally, recent studies have disclosed plectin mutations in patients with EB with pyloric atresia, an autosomal recessive syndrome, frequently with lethal consequences. Collectively, these observations attest to the phenotypic spectrum of plectin mutations, and provide the basis for accurate genetic counselling with prognostic implications, as well as for prenatal diagnosis in families at the risk of recurrence of the disease.
Can models of presence‐absence be used to scale abundance? Two case studies considering extremes in life history
Authors: Nielsen Scott E. , Johnson Chris J. , Heard Douglas C. , Boyce Mark S.
Published: March 2005

Understanding patterns of species occurrence and abundance is a central theme of ecology, natural resource management, and conservation. Although occurrence models have been widely used for describing species distribution, particularly for rare species, abundance models are less common, despite greater information for conservation and management. Because presence‐absence data are easier and less expensive to collect, predictions of abundance from patterns of occurrence could prove useful. We examined the relationship between occurrence and abundance for two species with very different life histories: bracken fern Pteridium aquilinum and moose Alces alces. We predicted that if occurrence and abundance were functionally related we should observe: 1) correlation between predicted probability of occurrence and observed abundance; 2) similar environmental covariates and estimated coefficients for occurrence models developed separately for low‐density, high‐density, and global data sites; and 3) parallel coefficients for the occurrence and abundance components of zero‐inflated count models. Probability of occurrence was not correlated with abundance‐when‐present for bracken fern, while evidence for a relationship for moose was apparent at densities of animals below 7 individuals per cutblock. Coefficients for models at different levels of density did not vary significantly. However, once occurrence was accounted for, measured environmental data appeared less important in describing abundance. For bracken, covariates of zero‐inflated count models differed in their expression of occurrence and abundance. Differences were less extreme for moose; however, results from the two‐process models suggest that distribution and abundance may be a function of different processes. Environmental factors influencing abundance may differ from those limiting distribution. Life history, scale, site history, and socio‐competitive processes further help shape patterns of abundance. Two‐stage modeling provides a powerful tool for describing animal and plant distribution where the processes of occurrence and abundance are influenced by different factors.
Prophylactic treatment effects on inhibitor risk: experience in one centre
Authors: Morado M. , Villar A. , Jiménez Yuste V. , Quintana M. , Hernandez Navarro F.
Published: March 2005

Summary.  Nowadays, the elective treatment for children with haemophilia is prophylaxis. There is a common consensus that this modality of therapeutic approach is not associated with a higher risk of inhibitor development. We analysed the inhibitor incidence in 50 haemophiliac children and its relationship with mutations, type of clotting factor used and treatment modality. There was a significant correlation between receiving on‐demand treatment and an increased incidence of inhibitors, independently of mutations or factor used. We advise putting haemophiliac children under prophylactic treatment as soon as possible, especially if they have mutations associated with high risk of inhibitor development, as prophylaxis is negatively associated with the development of inhibitors.
Orthopaedic manifestations of the hip in haemophilia – impaction bone grafting used in revision total hip arthroplasty in a haemophilic patient
Authors: Hope B. , Halliday B.
Published: March 2005

Summary.  The condition of haemophilia presents many challenges to the orthopaedic surgeon. Two such challenges include the haemophilic pseudotumour, a rare complication occurring in 1–2% of haemophiliacs, and the phenomenon of aseptic loosening of arthroplasty implants. This report presents a case involving the separate management of a pseudotumour and revision hip arthroplasty in the same hip using impaction bone grafting.