bluuebunny/crossref_metadata_2025 huggingface dataset:
History repackaged in the age of print: the Sanguozhi and Sanguo yanyi
Authors: MCLAREN ANNE E.
Published: June 2006

For over a millennium, the issue of the Shu-Han succession during the Three Kingdoms era (220–265 CE) has served as a proxy for debates about the relative merits of territorial control, blood relationship, and moral qualifications as grounds for imperial legitimacy in China. Debate reached a new height after the fall of north China during the twelfth century, a period when a revitalization of Confucian studies led to a greater interest in the publishing of private histories. This article deals with two little-known revisions of the official history of the Three Kingdoms period, the Sanguozhi, that sought to reflect the legitimacy debate at a time of alien conquest. It is argued that revisionist historians deviated from the norms of traditional historiography by devising new narrative strategies to further their political agenda. These innovations in turn influenced the formation of a new genre of historical fiction.
Is the major increase in notified campylobacteriosis in New Zealand real?
Authors: BAKER M. G. , SNEYD E. , WILSON N. A.
Published: June 2006

Notifications of campylobacteriosis by New Zealand medical practitioners have increased steadily in the last two decades. To determine if this increase is real, as opposed to a surveillance artefact, we examined both available notification (1980–2003) and hospitalization data (1995–2003). The similarity in the temporal pattern of increasing hospitalizations for campylobacteriosis, with that of notifications, is suggestive that this increase is indeed real. Although some risk factors for this disease have been identified (e.g. uncooked poultry consumption) it is unclear what the likely causes of the increasing rates are. The overall disease burden is also high compared with other developed countries (an annual notification rate of 396 cases per 100000 population in 2003), with highest rates in children aged 1–4 years, males, Europeans, and those living in urban areas. Given the large disease burden, further research and intervention studies should be public health priorities in this country.
Environmental and ecological determinants of West Nile virus occurrence in horses in North Dakota, 2002
Authors: MONGOH M. NDIVA , KHAITSA M. L. , DYER N. W.
Published: June 2006

West Nile virus (WNV) outbreak in North Dakota in 2002 included over 569 horse cases, clustered mainly in the eastern and northeastern parts of the state. The pattern of occurrence observed suggested existence of specific environmental and ecological factors that increased the risk for infection and illness in those locations. We developed a predictive model with factors that explained the pattern of WNV occurrence observed. Results indicated that surface elevation, temperature, precipitation, reported WNV-positive birds, reported WNV-positive humans, and reported WNV-positive mosquitoes were important predictors of occurrence in horses. However, case distance from water bodies was not significant in the model. Future predictive models of WNV occurrence in horses should take into account these factors in order to improve accuracy and reliability. Research into other potential determinants such as horse management factors are required to determine more differential risk factors associated with WNV occurrence in horses.
Eltern beurteilen die Entwicklung ihrer hochbegabten Kinder
Authors: Buch Susanne R. , Sparfeldt Jörn R. , Rost Detlef H.
Published: June 2006

Zusammenfassung. Untersucht wurde, ob sich - wie häufig behauptet - in Elterneinschätzungen gehäuft Entwicklungsbesonderheiten hochbegabter Kinder finden lassen. Bisherige Erkenntnisse beruhen zumeist auf Einzelfall- und/oder Gelegenheitsbeobachtungen bzw. auf Studien an selektiven Stichproben, häufig fehlt eine adäquate Vergleichsgruppe. Im Rahmen des “Marburger Hochbegabtenprojekts” beurteilten Eltern hochbegabter ([Formula: see text] = 135, n = 151) und Eltern durchschnittlich begabter ([Formula: see text] = 102, n = 136) Kinder jeweils die Entwicklung ihres Kindes hinsichtlich unterschiedlicher Aspekte. Beide Gruppen entstammten einer nicht zuvor selektierten Ausgangsstichprobe von N = 7023 Grundschulkindern. Sowohl retrospektive als auch konkurrente Einschätzungen wurden erhoben; neben standardisierten Ratings kamen auch offene Fragen zum Einsatz. Mittlere und konsistente Effekte fanden sich lediglich in standardisierten Elternratings zur sprachlichen und intellektuellen Entwicklung zugunsten der hochbegabten Kinder. In weiteren Entwicklungsaspekten (u.a. Persönlichkeit, soziale Entwicklung, Gesundheit, Motorik) wurden beide Gruppen von ihren Eltern sehr ähnlich beurteilt. Insgesamt ließen sich keine Belege für hochbegabungsspezifische Entwicklungsbesonderheiten finden. Selbst im Elternurteil zur sprachlichen und intellektuellen Entwicklung bestehen große Überlappungen zwischen beiden Gruppen.
Vergleichseffekte auf kognitive, affektive und motivationale Variablen
Authors: Pohlmann Britta , Möller Jens
Published: June 2006

Zusammenfassung. Nach den Annahmen des Internal/External Frame of Reference Models ( Marsh, 1986 ) verwenden Personen zur Ausbildung ihrer fachspezifischen Selbstkonzepte neben sozialen auch dimensionale Vergleichsinformationen. Sie vergleichen ihre Leistung in einem Bereich demnach nicht nur mit den Leistungen anderer (sozialer Vergleich), sondern auch mit ihren eigenen Leistungen in anderen Bereichen (dimensionaler Vergleich). Ziel der vorliegenden Untersuchung war es, das Auftreten beider Vergleichsprozesse experimentell nachzuweisen. Die Teilnehmer (N = 81 Studierende) erhielten zu zwei verschiedenen Aufgaben jeweils sozial vergleichende Leistungsrückmeldung und gaben anschließend ihre aufgabenspezifischen Fähigkeitseinschätzungen an. Für beide Aufgaben konnten sowohl Effekte sozialer als auch dimensionaler Vergleiche demonstriert werden. Zusätzliche Analysen der Selbstwirksamkeit und der Leistungszufriedenheit wiesen auf die Bedeutung sozialer und dimensionaler Vergleiche auch für weitere kognitive und affektive Variablen hin. Das aufgabenbezogene Interesse als motivationales Konstrukt scheint weniger von den beiden Vergleichsprozessen beeinflusst zu sein.
Mapping epitopes and antigenicity by site-directed masking
Authors: Paus Didrik , Winter Greg
Published: June 2006

Here we describe a method for mapping the binding of antibodies to the surface of a folded antigen. We first created a panel of mutant antigens (β-lactamase) in which single surface-exposed residues were mutated to cysteine. We then chemically tethered the cysteine residues to a solid phase, thereby masking a surface patch centered on each cysteine residue and blocking the binding of antibodies to this region of the surface. By these means we mapped the epitopes of several mAbs directed to β-lactamase. Furthermore, by depleting samples of polyclonal antisera to the masked antigens and measuring the binding of each depleted sample of antisera to unmasked antigen, we mapped the antigenicity of 23 different epitopes. After immunization of mice and rabbits with β-lactamase in Freund’s adjuvant, we found that the antisera reacted with both native and denatured antigen and that the antibody response was mainly directed to an exposed and flexible loop region of the native antigen. By contrast, after immunization in PBS, we found that the antisera reacted only weakly with denatured antigen and that the antibody response was more evenly distributed over the antigenic surface. We suggest that denatured antigen (created during emulsification in Freund’s adjuvant) elicits antibodies that bind mainly to the flexible regions of the native protein and that this explains the correlation between antigenicity and backbone flexibility. Denaturation of antigen during vaccination or natural infections would therefore be expected to focus the antibody response to the flexible loops.
Stem cell niches in the adult mouse heart
Authors: Urbanek Konrad , Cesselli Daniela , Rota Marcello , Nascimbene Angelo , De Angelis Antonella , Hosoda Toru , Bearzi Claudia , Boni Alessandro , Bolli Roberto , Kajstura Jan , Anversa Piero , Leri Annarosa
Published: June 2006

Cardiac stem cells (CSCs) have been identified in the adult heart, but the microenvironment that protects the slow-cycling, undifferentiated, and self-renewing CSCs remains to be determined. We report that the myocardium possesses interstitial structures with the architectural organization of stem cell niches that harbor long-term BrdU-retaining cells. The recognition of long-term label-retaining cells provides functional evidence of resident CSCs in the myocardium, indicating that the heart is an organ regulated by a stem cell compartment. Cardiac niches contain CSCs and lineage-committed cells, which are connected to supporting cells represented by myocytes and fibroblasts. Connexins and cadherins form gap and adherens junctions at the interface of CSCs–lineage-committed cells and supporting cells. The undifferentiated state of CSCs is coupled with the expression of α
4
-integrin, which colocalizes with the α
2
-chain of laminin and fibronectin. CSCs divide symmetrically and asymmetrically, but asymmetric division predominates, and the replicating CSC gives rise to one daughter CSC and one daughter committed cell. By this mechanism of growth kinetics, the pool of primitive CSCs is preserved, and a myocyte progeny is generated together with endothelial and smooth muscle cells. Thus, CSCs regulate myocyte turnover that is heterogeneous across the heart, faster at the apex and atria, and slower at the base–midregion of the ventricle.
Imaging of CNS myelin by positron-emission tomography
Authors: Stankoff Bruno , Wang Yanming , Bottlaender Michel , Aigrot Marie-Stephane , Dolle Frederic , Wu Chunying , Feinstein Douglas , Huang Guo-Feng , Semah Frank , Mathis Chester A. , Klunk William , Gould Robert M. , Lubetzki Catherine , Zalc Bernard
Published: June 2006

Promoting myelin repair is one of the most promising therapeutic avenues in the field of myelin disorders. In future clinical trials, evaluation of remyelination will require a reliable and quantifiable myelin marker to be used as a surrogate marker. To date, MRI assessment lacks specificity for evaluating the level of remyelination within the brain. Here, we describe 1,4-bis(
p
-aminostyryl)-2-methoxy benzene (BMB), a synthesized fluorescent molecule, that binds selectively to myelin both
ex vivo
and
in vivo
. The binding of BMB to myelin allows the detection of demyelinating lesions in an experimental autoimmune encephalitis model of demyelination and allows a mean for quantifying myelin loss in dysmyelinating mutants. In multiple sclerosis brain, different levels of BMB binding differentiated remyelination in shadow plaques from either demyelinated lesions or normal-appearing white matter. After systemic injection, BMB crosses the blood–brain barrier and binds to myelin in a dose-dependent and reversible manner. Finally, we provide evidence that
11
C-radiolabeled BMB can be used
in vivo
to image CNS myelin by positron-emission tomography in baboon. Our results provide a perspective for developing a brain myelin imaging technique by positron-emission tomography.
Nascent DNA processing by RecJ favors lesion repair over translesion synthesis at arrested replication forks in
Escherichia coli
Authors: Courcelle Charmain T. , Chow Kin-Hoe , Casey Andrew , Courcelle Justin
Published: June 2006

DNA lesions that arrest replication can lead to rearrangements, mutations, or lethality when not processed accurately. After UV-induced DNA damage in
Escherichia coli
, RecA and several
recF
pathway proteins are thought to process arrested replication forks and ensure that replication resumes accurately. Here, we show that the RecJ nuclease and RecQ helicase, which partially degrade the nascent DNA at blocked replication forks, are required for the rapid recovery of DNA synthesis and prevent the potentially mutagenic bypass of UV lesions. In the absence of RecJ, or to a lesser extent RecQ, the recovery of replication is significantly delayed, and both the recovery and cell survival become dependent on translesion synthesis by polymerase V. The RecJ-mediated processing is proposed to restore the region containing the lesion to a form that allows repair enzymes to remove the blocking lesion and DNA synthesis to resume. In the absence of nascent DNA processing, polymerase V can synthesize past the lesion to prevent lethality, although this occurs with slower kinetics and a higher frequency of mutagenesis.
Positive selection driving diversification in plant secondary metabolism
Authors: Benderoth Markus , Textor Susanne , Windsor Aaron J. , Mitchell-Olds Thomas , Gershenzon Jonathan , Kroymann Juergen
Published: June 2006

In
Arabidopsis thaliana
and related plants, glucosinolates are a major component in the blend of secondary metabolites and contribute to resistance against herbivorous insects. Methylthioalkylmalate synthases (MAM) encoded at the
MAM
gene cluster control an early step in the biosynthesis of glucosinolates and, therefore, are central to the diversification of glucosinolate metabolism. We sequenced bacterial artificial chromosomes containing the
MAM
cluster from several
Arabidopsis
relatives, conducted enzyme assays with heterologously expressed
MAM
genes, and analyzed
MAM
nucleotide variation patterns. Our results show that gene duplication, neofunctionalization, and positive selection provide the mechanism for biochemical adaptation in plant defense. These processes occur repeatedly in the history of the
MAM
gene family, indicating their fundamental importance for the evolution of plant metabolic diversity both within and among species.
A
Vibrio cholerae
protease needed for killing of
Caenorhabditis elegans
has a role in protection from natural predator grazing
Authors: Vaitkevicius Karolis , Lindmark Barbro , Ou Gangwei , Song Tianyan , Toma Claudia , Iwanaga Masaaki , Zhu Jun , Andersson Agneta , Hammarström Marie-Louise , Tuck Simon , Wai Sun Nyunt
Published: June 2006

Vibrio cholerae
is the causal bacterium of the diarrheal disease cholera, and its growth and survival are thought to be curtailed by bacteriovorous predators, e.g., ciliates and flagellates. We explored
Caenorhabditis elegans
as a test organism after finding that
V. cholerae
can cause lethal infection of this nematode. By reverse genetics we identified an extracellular protease, the previously uncharacterized PrtV protein, as being necessary for killing. The killing effect is associated with the colonization of bacteria within the
Caenorhabditis elegans
intestine. We also show that PrtV is essential for
V. cholerae
in the bacterial survival from grazing by the flagellate
Cafeteria roenbergensis
and the ciliate
Tetrahymena pyriformis
. The PrtV protein appears to have an indirect role in the interaction of
V. cholerae
with mammalian host cells as judged from tests with tight monolayers of human intestinal epithelial cells. Our results demonstrate a key role for PrtV in
V. cholerae
interaction with grazing predators, and we establish
Caenorhabditis elegans
as a convenient organism for identification of
V. cholerae
factors involved in host interactions and environmental persistence.
Phylogenetic analysis of the “ECE” (CYC/TB1) clade reveals duplications predating the core eudicots
Authors: Howarth Dianella G. , Donoghue Michael J.
Published: June 2006

Flower symmetry is of special interest in understanding angiosperm evolution and ecology. Evidence from the Antirrhineae (snapdragon and relatives) indicates that several TCP gene-family transcription factors, especially
CYCLOIDEA
(
CYC
) and
DICHOTOMA
(
DICH
), play a role in specifying dorsal identity in the corolla and androecium of monosymmetric (bilateral) flowers. Studies of rosid and asterid angiosperms suggest that orthologous TCP genes may be important in dorsal identity, but there has been no broad phylogenetic context to determine copy number or orthology. Here, we compare published data from rosids and asterids with newly collected data from ranunculids, caryophyllids, Saxifragales, and Asterales to ascertain the phylogenetic placement of major duplications in the “ECE” (CYC/TB1) clade of TCP transcription factors. Bayesian analyses indicate that there are three major copies of “CYC” in the ECE clade, and that duplications leading to these copies predate the core eudicots. CYC1 contains no subsequent duplications and may not be expressed in floral tissue. CYC3 exhibits similar patterns of duplication to CYC2 in several groups. Using RT-PCR, we show that, in flowers of
Lonicera morrowii
(Caprifoliaceae),
DipsCYC2B
is expressed in the four dorsal petals and not in the ventral petal.
DipsCYC3B
is expressed in flower and petal primordia, possibly most strongly in the ventral petal.
Purinergic signaling induces thrombospondin-1 expression in astrocytes
Authors: Tran Minh D. , Neary Joseph T.
Published: June 2006

Thrombospondin (TSP)-1, a multidomain glycoprotein, is secreted from astrocytes and promotes synaptogenesis. However, little is known about the mechanisms regulating its expression and release. In this article, we report that purinergic signaling participates in the production and secretion of TSP-1. Treatment of primary cultures of rat cortical astrocytes with extracellular ATP caused an increase in TSP-1 expression in a time- and concentration-dependent manner and was inhibited by antagonists of P2 and P1 purinergic receptors. Agonist studies revealed that UTP, but not 2′,3′-O-(4-benzoyl)benzoyl-ATP, 2-methylthio-ADP, adenosine, or 5′-N-ethyl-carboxamidoadenosine, caused a significant increase in TSP-1 expression. In addition, release of TSP-1 was stimulated by ATP and UTP but not by 2-methylthio-ADP or adenosine. Additional studies indicated that P2Y4receptors stimulate both TSP-1 expression and release. P2Y receptors are coupled to protein kinase cascades, and signaling studies demonstrated that blockade of mitogen-activated protein kinases or Akt inhibited ATP- and UTP-induced TSP-1 expression. Using anin vitromodel of CNS trauma that stimulates release of ATP, we found that TSP-1 expression increased after mechanical strain and was completely blocked by a P2 receptor antagonist and by inhibition of p38/mitogen-activated protein kinase and Akt, thereby indicating a major role for P2 receptor/protein kinase signaling in TSP-1 expression induced by trauma. We conclude that TSP-1 expression can be regulated by activation of P2Y receptors, particularly P2Y4, coupled to protein kinase signaling pathways and suggest that purinergic signaling may be an important factor in TSP-1-mediated cell-matrix and cell–cell interactions such as those occurring during development and repair.
Essential and mutually compensatory roles of α-mannosidase II and α-mannosidase IIx in
N
-glycan processing
in vivo
in mice
Authors: Akama Tomoya O. , Nakagawa Hiroaki , Wong Nyet Kui , Sutton-Smith Mark , Dell Anne , Morris Howard R. , Nakayama Jun , Nishimura Shin-Ichiro , Pai Ashok , Moremen Kelley W. , Marth Jamey D. , Fukuda Michiko N.
Published: June 2006

Many proteins synthesized through the secretory pathway receive posttranslational modifications, including
N
-glycosylation. α-Mannosidase II (MII) is a key enzyme converting precursor high-mannose-type
N
-glycans to matured complex-type structures. Previous studies showed that MII-null mice synthesize complex-type
N
-glycans, indicating the presence of an alternative pathway. Because α-mannosidase IIx (MX) is a candidate enzyme for this pathway, we asked whether MX functions in
N
-glycan processing by generating MII/MX double-null mice. Some double-nulls died between embryonic days 15.5 and 18.5, but most survived until shortly after birth and died of respiratory failure, which represents a more severe phenotype than that seen in single-nulls for either gene. Structural analysis of
N
-glycans revealed that double-nulls completely lack complex-type
N
-glycans, demonstrating a critical role for at least one of these enzymes for effective
N
-glycan processing. Recombinant mouse MX and MII showed identical substrate specificities toward
N
-glycan substrates, suggesting that MX is an isozyme of MII. Thus, either MII or MX can biochemically compensate for the deficiency of the other
in vivo
, and either of two is required for late embryonic and early postnatal development.
Early establishment of diverse T cell receptor profiles for influenza-specific CD8+CD62Lhimemory T cells
Authors: Kedzierska Katherine , Venturi Vanessa , Field Kenneth , Davenport Miles P. , Turner Stephen J. , Doherty Peter C.
Published: June 2006

Single-cell analysis of endogenous, primary CD8+T cell responses to the influenza DbNP366and DbPA224epitopes indicates that prominent clonotypes bearing “public” or “shared” T cell receptors (TCRs) subset early into CD62Lhiand CD62Llopopulations. The CD62Lloeffectors divide more and are rapidly eliminated during the contraction phase, whereas stable CD62Lhimemory populations persist in the long-term. Reflecting the high frequency of small CD62Lhiclones expressing “private” TCRs, the TCR diversity range per mouse is generally two times higher within the CD62LhiCD8+DbNP366+set (1.6 times higher for CD62LhiCD8+DbPA224+) from 8 to >180 days after antigen challenge. Memory CD8+CD62LhiT cell precursors thus segregate from the outset into populations expressing “best-fit” and “suboptimal” TCR characteristics, with this pattern being maintained stably thereafter. Hence, our analysis suggests that early establishment of influenza-specific memory within the CD8+CD62Lhisubset preserves clonal diversity and prevents “overdominance” by a few public, or shared, clones.
Compartmentalized signaling of Ras in fission yeast
Authors: Onken Brian , Wiener Heidi , Philips Mark R. , Chang Eric C.
Published: June 2006

Compartment-specific Ras signaling is an emerging paradigm that may explain the multiplex outputs from a single GTPase. The fission yeast,
Schizosaccharomyces pombe,
affords a simple system in which to study Ras signaling because it has a single Ras protein, Ras1, that regulates two distinct pathways: one that controls mating through a Byr2-mitogen-activated protein kinase cascade and one that signals through Scd1-Cdc42 to maintain elongated cell morphology. We generated Ras1 mutants that are restricted to either the endomembrane or the plasma membrane. Protein binding studies showed that each could interact with the effectors of both pathways. However, when examined in
ras1
null cells, endomembrane-restricted Ras1 supported morphology but not mating, and, conversely, plasma membrane-restricted Ras1 supported mating but did not signal to Scd1-Cdc42. These observations provide a striking demonstration of compartment-specific Ras signaling and indicate that spatial specificity in the Ras pathway is evolutionarily conserved.
Rb is dispensable for self-renewal and multilineage differentiation of adult hematopoietic stem cells
Authors: Walkley Carl R. , Orkin Stuart H.
Published: June 2006

Stem cells have been identified as essential for maintaining multiple organ systems, including the hematopoietic system. The distinct cell fates of self-renewal and differentiation of hematopoietic stem cells (HSCs) depend on cell division. Recently, several negative regulators of the cell cycle, such as the cyclin-dependent kinase inhibitors p21
Cip1
, p27
Kip1
, and p16
INK4a
/p19
ARF
, have been demonstrated to have a role in regulating HSC fate decisions, suggesting that regulation of the G
1
–S phase transition can contribute to HSC self-renewal. Because the retinoblastoma protein, Rb, plays a central role in the regulation of the G
1
–S phase cell cycle, we sought to determine whether it has an intrinsic role in the regulation of HSC fate. Surprisingly, we found that HSC function was essentially normal in the absence of Rb.
Rb
Δ/Δ
HSCs contributed normally to both myeloid and lymphoid lineages in both primary and secondary recipients, and no evidence of transformation was observed. Additionally, we observed a mild myeloid expansion and decrease in mature B cells within the
Rb
Δ/Δ
bone marrow but a similar contribution to phenotypic HSC populations compared with nondeleted bone marrow. The Rb family members p107 and p130 were not deregulated in cells in which Rb had been deleted, as determined by quantitative RT-PCR on the highly enriched stem and primitive progenitor cell lin
−
c-Kit
+
Sca-1
+
population. These studies demonstrate that Rb is not intrinsically required for self-renewal and multilineage differentiation of adult HSCs.
Endonuclease G: A role for the enzyme in recombination and cellular proliferation
Authors: Huang Ke-Jung , Ku Chia-Chi , Lehman I. Robert
Published: June 2006

Our earlier studies had suggested that endonuclease G (EndoG), a member of the evolutionarily conserved DNA/RNA nonspecific ββα-Me-finger nuclease family, functioned in the
a
sequence-mediated segment inversion observed during herpes simplex virus 1 replication. To test this hypothesis, we used RNA interference to reduce the level of EndoG in mammalian cells in culture. Reduction of EndoG produced a small but statistically significant decrease in
a
sequence-mediated recombination, suggesting that EndoG does play a role in this process. We also observed that reduction in the level of EndoG resulted in a deficiency in cell proliferation. Cells with a reduced level of EndoG also showed changes in cell distribution in the cell cycle, producing a pattern characteristic of cells that have been arrested in the G
2
phase. These findings suggest that EndoG is required for normal cellular proliferation.
Synergic effect of polymorphisms inERCC65′ flanking region andcomplement factor Hon age-related macular degeneration predisposition
Authors: Tuo Jingsheng , Ning Baitang , Bojanowski Christine M. , Lin Zhong-Ning , Ross Robert J. , Reed George F. , Shen Defen , Jiao Xiaodong , Zhou Min , Chew Emily Y. , Kadlubar Fred F. , Chan Chi-Chao
Published: June 2006

This study investigates age-related macular degeneration (AMD) genetic risk factors through identification of a functional single-nucleotide polymorphism (SNP) and its disease association. We choseERCC6because of its roles in the aging process, DNA repair, and ocular degeneration from the gene disruption. Bioinformatics indicated a putative binding-element alteration on the sequence containing C−6530>G SNP in the 5′ flanking region ofERCC6from Sp1 on the C allele to SP1, GATA-1, and OCT-1 on the G allele. Electrophoretic mobility shift assays displayed distinctive C and G allele-binding patterns to nuclear proteins. Luciferase expression was higher in the vector construct containing the G allele than that containing the C allele. A cohort of 460 advanced AMD cases and 269 age-matched controls was examined along with pathologically diagnosed 57 AMD and 18 age-matched non-AMD archived cases.ERCC6C−6530>G was associated with AMD susceptibility, both independently and through interaction with an SNP (rs380390) in the complement factor H (CFH) intron reported to be highly associated with AMD. A disease odds ratio of 23 was conferred by homozygozity for risk alleles at bothERCC6andCFHcompared with homozygozity for nonrisk alleles. Enhanced ERCC6 expression was observed in lymphocytes from healthy donors bearing ERCC6 C−6530>G alleles. Intense immunostaining of ERCC6 was also found in AMD eyes fromERCC6C−6530>G carriers. The strong AMD predisposition conferred by theERCC6andCFHSNPs may result from biological epistasis, because ERCC6 functions in universal transcription as a component of RNA pol I transcription complex.
A constant production hypothesis guides leaf venation patterning
Authors: Dimitrov Pavel , Zucker Steven W.
Published: June 2006

We propose a theoretical mechanism that enables the elaboration of veins to supply distant cells during leaf development. In contrast to the more standard view that a signal (e.g., auxin) is produced at isolated sites to stimulate growth, we determine the consequences of the hypothesis that auxin is produced at a constant rate in every cell. High concentration sites for auxin emerge naturally in a reaction–diffusion model, together with global information about leaf shape and existing venation. Because the global information is encoded as auxin concentration and its gradient, those signals provide individual cells with sufficient information to determine their own fate. Unlike other models, a single substance suffices for the reaction–diffusion at early, but not initial, stages of development. Neither complex interactions nor predetermination are necessary. We predict angiosperm areolation patterns in simulation, and our model further implies the Sachs Canalization Hypothesis and resolves a dilemma regarding the role of auxin in cell growth.
Kinetic effects of temperature on rates of genetic divergence and speciation
Authors: Allen Andrew P. , Gillooly James F. , Savage Van M. , Brown James H.
Published: June 2006

Latitudinal gradients of biodiversity and macroevolutionary dynamics are prominent yet poorly understood. We derive a model that quantifies the role of kinetic energy in generating biodiversity. The model predicts that rates of genetic divergence and speciation are both governed by metabolic rate and therefore show the same exponential temperature dependence (activation energy of ≈0.65 eV; 1 eV = 1.602 × 10
−19
J). Predictions are supported by global datasets from planktonic foraminifera for rates of DNA evolution and speciation spanning 30 million years. As predicted by the model, rates of speciation increase toward the tropics even after controlling for the greater ocean coverage at tropical latitudes. Our model and results indicate that individual metabolic rate is a primary determinant of evolutionary rates: ≈10
13
J of energy flux per gram of tissue generates one substitution per nucleotide in the nuclear genome, and ≈10
23
J of energy flux per population generates a new species of foraminifera.
The Eδ enhancer controls the generation of CD4−CD8− αβTCR-expressing T cells that can give rise to different lineages of αβ T cells
Authors: Aifantis Iannis , Bassing Craig H. , Garbe Annette I. , Sawai Katie , Alt Frederick W. , von Boehmer Harald
Published: June 2006

It is well established that the pre–T cell receptor for antigen (TCR) is responsible for efficient expansion and differentiation of thymocytes with productive TCRβ rearrangements. However, Ptcra- as well as Tcra-targeting experiments have suggested that the early expression of Tcra in CD4−CD8− cells can partially rescue the development of αβ CD4+CD8+ cells in Ptcra-deficient mice. In this study, we show that the TCR Eδ but not Eα enhancer function is required for the cell surface expression of αβTCR on immature CD4−CD8− T cell precursors, which play a crucial role in promoting αβ T cell development in the absence of pre-TCR. Thus, αβTCR expression by CD4−CD8− thymocytes not only represents a transgenic artifact but occurs under physiological conditions.
Forced usage of positively charged amino acids in immunoglobulin CDR-H3 impairs B cell development and antibody production
Authors: Ippolito Gregory C. , Schelonka Robert L. , Zemlin Michael , Ivanov Ivaylo I. , Kobayashi Ryoki , Zemlin Cosima , Gartland G. Larry , Nitschke Lars , Pelkonen Jukka , Fujihashi Kohtaro , Rajewsky Klaus , Schroeder Harry W.
Published: June 2006

Tyrosine and glycine constitute 40% of complementarity determining region 3 of the immunoglobulin heavy chain (CDR-H3), the center of the classic antigen-binding site. To assess the role of DH RF1-encoded tyrosine and glycine in regulating CDR-H3 content and potentially influencing B cell function, we created mice limited to a single DH encoding asparagine, histidine, and arginines in RF1. Tyrosine and glycine content in CDR-H3 was halved. Bone marrow and spleen mature B cell and peritoneal cavity B-1 cell numbers were also halved, whereas marginal zone B cell numbers increased. Serum immunoglobulin G subclass levels and antibody titers to T-dependent and T-independent antigens all declined. Thus, violation of the conserved preference for tyrosine and glycine in DH RF1 alters CDR-H3 content and impairs B cell development and antibody production.
Nepmucin, a novel HEV sialomucin, mediates L-selectin–dependent lymphocyte rolling and promotes lymphocyte adhesion under flow
Authors: Umemoto Eiji , Tanaka Toshiyuki , Kanda Hidenobu , Jin Soojung , Tohya Kazuo , Otani Kazuhiro , Matsutani Takahiro , Matsumoto Masanori , Ebisuno Yukihiko , Jang Myoung Ho , Fukuda Minoru , Hirata Takako , Miyasaka Masayuki
Published: June 2006

Lymphocyte trafficking to lymph nodes (LNs) is initiated by the interaction between lymphocyte L-selectin and certain sialomucins, collectively termed peripheral node addressin (PNAd), carrying specific carbohydrates expressed by LN high endothelial venules (HEVs). Here, we identified a novel HEV-associated sialomucin, nepmucin (mucin not expressed in Peyer's patches [PPs]), that is expressed in LN HEVs but not detectable in PP HEVs at the protein level. Unlike conventional sialomucins, nepmucin contains a single V-type immunoglobulin (Ig) domain and a mucin-like domain. Using materials affinity-purified from LN lysates with soluble L-selectin, we found that two higher molecular weight species of nepmucin (75 and 95 kD) were decorated with oligosaccharides that bind L-selectin as well as an HEV-specific MECA-79 monoclonal antibody. Electron microscopic analysis showed that nepmucin accumulates in the extended luminal microvillus processes of LN HEVs. Upon appropriate glycosylation, nepmucin supported lymphocyte rolling via its mucin-like domain under physiological flow conditions. Furthermore, unlike most other sialomucins, nepmucin bound lymphocytes via its Ig domain, apparently independently of lymphocyte function–associated antigen 1 and very late antigen 4, and promoted shear-resistant lymphocyte binding in combination with intercellular adhesion molecule 1. Collectively, these results suggest that nepmucin may serve as a dual-functioning PNAd in LN HEVs, mediating both lymphocyte rolling and binding via different functional domains.
Scale formation in selected western North Atlantic flatfishes
Authors: Able K. W. , Lamonaca J. C.
Published: June 2006

Patterns of scale formation (onset, completion and spatial pattern) were examined for five species of flatfishes in four families (Paralichthyidae: summer flounder Paralichthys dentatus, smallmouth flounder Etropus microstomus, Scophthalmidae: windowpane Scophthalmus aquosus, Pleuronectidae: winter flounder Pseudopleuronectes americanus and Soleidae: hogchoker Trinectes maculatus, to determine if the patterns are a useful indicator for the transition from the larval to the juvenile periods. In all species (except T. maculatus in which samples were limited), the ontogenetic pattern was very similar with onset of scale formation occurring on the lateral surface of the caudal peduncle, then spreading anteriorly along the presumptive lateral line, then laterally over the body, on to the head, and eventually on to the median fins. The timing of scale formation, relative to fish size, was late relative to other morphological and behavioural characters (i.e. fin ray formation, eye migration and settlement). The onset of scale formation, across all species, occurred at 9·0–27·0 mm total length (LT), at the same approximate size as eye migration and settlement. Completion of scale formation on the body occurred at 22–54 mm LT but completion of scale formation on the fins did not occur until 44–88 mm LT. Thus completion of scale formation in these flatfishes is apparently the last external morphological change to occur during the larval to juvenile transition and, as a result, is not completed until approximately one third (S. aquosus and P. dentatus) to one fourth (P. americanus) or about the same time (E. microstomus and T. maculatus) as the size at first reproduction. This character may have relevance to defining the end of the larval period and the beginning of the juvenile period in flatfishes and other fishes. In addition, the pattern of scale formation may be useful in enhancing understanding of systematics, functional morphology and habitat use.
Serum biliverdin as source of colouration upon sexual maturation in male blue‐throated wrasse Notolabrus tetricus
Authors: Gagnon M. M.
Published: June 2006

The blue colour observed in the serum of female blue‐throated wrasse Notolabrus tetricus was related to the presence of biliverdin. The biliverdin is probably stored in the female's serum until deposited in the skin upon transition to the male reproductive status, resulting in the brilliant blue colouration typical of males of this protogynous labrid species.
Fatigue is a behavioural response in respirometer‐confined smallmouth bass
Authors: Peake S. J. , Farrell A. P.
Published: June 2006

Fatigue in respirometer‐confined smallmouth bass Micropterus dolomieu was confirmed as being largely a behavioural response, and not brought about by depletion of anaerobic fuel stores. While data collected from these fish did not preclude the possibility that the behavioural response was triggered when some physiological threshold was exceeded, locomotory gait transition patterns in confined fish exposed to increasing water velocities support an alternate hypothesis. This is that fatigue is a behavioural decision made at (or near) the gait transition swimming speed, in an effort to avoid activity that, by virtue of the limited space in a typical respirometer, is energetically inefficient and biomechanically difficult.
Endocrine disrupting effects on the nesting behaviour of male three‐spined sticklebackGasterosteus aculeatusL.
Authors: Brian J. V. , Augley J. J. , Braithwaite V. A.
Published: June 2006

The analysis of patterns of temporal variability in the nesting behaviour of male three‐spined sticklebackGasterosteus aculeatusexposed to the synthetic oestrogen, 17β‐ethinylestradiol, revealed immediate, but transient, treatment‐related effects. Glueing frequency and time spent near nest were significantly reduced in exposed fish at the beginning of the experiment. The expression of these behaviours subsequently recovered and there was no effect of treatment on nest building success.
Movement patterns of the round stingray Urobatis halleri(Cooper) near a thermal outfall
Authors: Vaudo J. J. , Lowe C. G.
Published: June 2006

Fine‐scale movements and site fidelity of round stingrays Urobatis halleri at Seal Beach California, U.S.A., were examined using acoustic telemetry. Actively tracked fish generally exhibited limited nearshore movement, with greater distances travelled at night when the tide was ebbing than during the day with ebbing tides. Increases in round stingray activity were associated with increases in ambient temperature. Passively tracked fish showed seasonal patterns in their presence at Seal Beach. Males left Seal Beach during the autumn, returned the following spring, and remained in the area until the following autumn. Females spent far less time at Seal Beach, remaining in the area for a few weeks during June and July. Passively tracked round stingrays were recorded more often in the warm waters of the San Gabriel River mouth (the location of a thermal outfall from an electric‐generating station) than adjacent beaches, with fish often returning to Seal Beach after periods of absence. Anthropogenic effects resulting from coastal development may have created environmental conditions (i.e. warmer water and finer sediments) that influence the movements and site fidelity of round stingrays.
Environmental factors as forces structuring the fish community of the Elbe Estuary
Authors: Thiel R. , Sepúlveda A. , Kafemann R. , Nellen W.
Published: June 2006

Smelt, flounder, eel, three‐spined stickleback, twaite shad, ruffe and herring were the major species among 62 forming the fish community of the Elbe estuary. Species richness, species diversity, evenness and total fish biomass decreased in the upstream direction. Total abundance was greatest during summer. Salinity was the most significant physico‐chemical factor affecting species richness and total fish biomass, whereas water temperature was the best predictor of total abundance. Marine fish species decreased with decreasing salinity, while the freshwater species roach and ide were absent at salinities > 15‰. Bream, blue bream, white bream, perch and pikeperch occurred more frequently in shallow marginal regions with lower current velocities, while herring and other marine species occurred closer to the deep central regions with high current velocities. Annual and seasonal variations of the community structure mainly reflected in population dynamics of smelt, flounder, twaite shad, three‐spined stickleback and eel, especially those of 0‐age smelt. Populations of smelt and ruffe and their importance in the fish community increased between 1989 and 1992, while those of twaite shad and eel decreased. At oxygen concentrations <3 mg I1, smelt and flounder were rare, but eels were at their maximum at 3.5 mg I−1. Changes of species composition and fish abundance were closely related to daytime and tidal cycle.
Early life characteristics of pike, Esox lucius, in rearing ponds: temporal survival pattern and ontogenetic diet shifts
Authors: Bry C. , Bonamy F. , Manelphe J. , Duranthon B.
Published: June 2006

Survival, biomass and diet of pike, Esox lucius, larvae and juveniles were studied over 3 years by stocking free embryos at a density of six fish m−2 in 12 drainable outdoor ponds. The ponds were sequentially drained at six larval/juvenile developmental stages, up to a total length (T.L.) of 139 mm. The mean rate of survival at harvest decreased irregularly over time and the highest mortality rates were recorded during the early larval period (13 to 27 mm t.l.) and two intervals of the juvenile period (46 to 99 mm T.L. and 121 to 139 mm t.l.). Mean biomass increased dramatically between 46 mm T.L. (19.8 kg ha−1) and 121 mm T.L. (181.8 kg ha−1) and stabilized between 121 and 139 mm t.l. Sharp increases in the mean weight coefficient of variation were recorded during the early larval period (13 to 27 mm t.l.) and between 74 and 121 mm t.l. (development of cannibalism). Diet breadths were relatively narrow in pike larvae and reached maximum levels in 99 mm t.l. juveniles. Average‐sized pike exhibited a sequence of size‐dependent shifts from a diet composed primarily (in terms of weight) of micro‐crustaceans (at 13 mm t.l.), to chironomid larvae (at 74 to 99 mm t.l.), and finally macrocrustaceans (at 121 to 139 mm t.l.). Cannibalism was detected first among the largest fish at the 74 mm t.l. stage. Between‐year diet similarity at various developmental stages was consistently high. In 70 mm t.l. fish harvested from different ponds, we found significant among‐pond differences in diet composition; however, similar trends of diet changes in relation to fish size were observed from pond to pond. Our results are discussed in light of existing knowledge of young pike trophic ecology and current aquaculture practices.
Electroencephalograms and cerebral blood flow in carp, Cyprinus carpio, subjected to acute hypoxia
Authors: Yoshikawa H. , Ishida Y. , Kawata K. , Kawai F. , Kanamori M.
Published: June 2006

Changes in electroencephalogams (EEG) and cerebral blood flow were examined in carp immobilized with a muscle relaxant during 60 min hypoxia (water Po2 of approximately 20 mmHg) and subsequent 30 min normoxia. The amplitude of EEG waves recorded from the telencephalon decreased gradually but slightly with the progression of hypoxia, whereas the telencephalic blood flow increased mainly due to an increased blood velocity. These findings suggested that cerebral activity during hypoxia was compensated to some degree by increased cerebral blood flow. However, carp showed large variations in the patterns of EEG responses and cerebral blood flow.
Effects of thermal stress on respiratory responses to hypoxia of a South American Prochilodontid fish, Prochilodus scrofa
Authors: Fernandes M. N. , Barrionuevo W. R. , Rantin F. T.
Published: June 2006

Oxygen consumption (V̇o2) and respiratory variables were measured in the Prochilodontid fish, Prochilodus scrofa exposed to graded hypoxia after changes in temperature. The measurements were performed on fish acclimated to 25°C and in four further groups also acclimated to 25°C and then changed to 15, 20, 30 and 35°C. An increase in V̇o2 occurred with rising temperature, but at each temperature V̇o2 was kept constant over a wide range of O2 tensions of inspired water (Pio2). The critical oxygen tensions (Pco2) were Pio2= 22 mmHg for 25°C acclimated specimens and after transfer from 25°C to 15, 20, 30 and 35°C the Pco2 changed to Pio2= 28, 22, 24 and 45 mmHg, respectively. Gill ventilation (V̇G) increased or decreased following the changes in V̇o2 as the temperature changed and was the result of an accentuated increase in breath frequency. During hypoxia the increases in V̇G were characterized by larger increases in breath volume. Oxygen extraction was kept almost constant at about 63% regardless of temperature and ambient oxygen tensions in normoxia and moderate hypoxia (Po2∼70 mmHg). P. scrofa showed high tolerance to hypoxia after abrupt changes in temperature although its survival upon transfer to 35°C could become limited by the capacity of ventilatory mechanisms to alleviate hypoxic stress.
Genetic relationships of four Taiwan mullets (Pisces: Perciformes: Mugilidae)
Authors: Lee S. C. , Chang J. T. , Tsu Y. Y.
Published: June 2006

Electrophoretic data for 19 presumptive gene loci separated Mugil cephalus from Liza spp. with Nei's genetic distance of 0.863, and from Valamugil formosae with 0.703, and from both Liza and Valamugil with 0.783. Within the genus Liza, Nei's genetic distance was only 0.237 between L. affinis and L. macrolepis.
Chernobyl‐derived radiocaesium in fish as dependent on water quality and lake morphometry
Authors: Särkkä Jukka , Jämsä Aulis , Luukko Antti
Published: June 2006

137Cs concentrations in perch Perca fluviatilis, pike Esox lucius and roach Rutilus rutilus obtained from lakes of different size and water quality in an area which received about 10–67 kBq m−2137Cs, were compared with environmental data. Radiocaesium concentrations were highest in pike, and were about two to three times higher in the pike and perch than in the roach. The largest perch had about four times more 137Cs than the smallest ones, but the activities in the pike and roach were independent of fish size. All of the water quality parameters examined correlated with 137Cs concentrations in the fish, but the concentrations of 137Cs in the bottom sediment did not. l37Cs fallout and water retention time in lakes showed a positive correlation with fish 137Cs, while the size of the catchment area, phosphorus content of the water, water colour, pH and electrical conductivity showed a negative one. Thus there was more 137Cs in the fish from the oligotrophic lakes than from the eutrophic ones, from the less humic lakes than from the more humic ones, from the more acid than from the less acid ones and from the lakes containing less potassium than from those containing more potassium. The depth, area and volume of the lake did not affect radiocaesium in the fish. Regression equations are presented for predicting 137Cs in fish on the basis of environmental data. Fallout, total phosphorus and pH together had the highest influence in multiple regression models but were less significant in the roach than in the perch and pike.