bluuebunny/crossref_metadata_2025 huggingface dataset:
Why are group‐living badgers (Meles meles) sexually dimorphic?
Authors: Johnson Dominic D. P. , Macdonald David W.
Published: July 2002

One of the hypotheses proposed to account for why badgers Meles meles are highly social in the U.K., the resource dispersion hypothesis, is that patchy resources are unpredictably dispersed in the environment and therefore must be shared, but that these patches are rich enough, when available, to support several badgers at any one time. Previous empiricists in our study site at Wytham Woods calculated that single patches could be rich enough to support 30 badgers in a night. The sustained increase in population density in Wytham Woods suggests that food was not limiting and territories were below capacity, and therefore that feeding competition was relatively low. Low feeding competition would predict an absence of dimorphism in trophic apparatus between the sexes. Contrary to this, significant sexual dimorphism was found, after removing effects resulting from body size allometry, in canine cross‐section length, width (both P < 0.0001) and skull breadth (P < 0.001). The differences in canine dimensions were still significant when allometry of both body length and skull breadth are accounted for statistically (P < 0.0001). It is therefore suggested that feeding competition may not necessarily be low, which would have implications for understanding the costs of social behaviour. Alternative explanations involving sexual selection and phylogenetic inertia are discussed.
A new atlantasellid isopod (Asellota: Aselloidea) from the flooded coastal karst of the Dominican Republic (Hispaniola): evidence for an exopod on a thoracic limb and biogeographical implications
Authors: Jaume Damià
Published: July 2002

A new representative of the thus far monotypic, Bermudan aselloid family Atlantasellidae is described from the freshwater layers of two coastal sinkholes on the south‐west Dominican Republic, Hispaniola. Atlantasellus dominicanus sp. nov. is extraordinary among isopods in retaining a remnant of the exopod on one of its pereiopods; no other isopod is known to express a schizopodous condition of thoracic limbs. The locomotory behaviour, body volvation habits, and apparent specificity of the new taxon for life on submerged decaying wood in cave waters are described. Analysis of palaeogeographic and ecological evidence supports the interpretation of the Atlantasellidae as a thalassoid lineage, contrary to previous phylogenetically supported assumptions considering them to be an ancient, freshwater lineage.
Mortality patterns of otters (Lutra lutra) from eastern Germany
Authors: Hauer Silke , Ansorge Hermann , Zinke Olaf
Published: July 2002

Data obtained from the dissection of 1067 otters Lutra lutra were used to compare the causes of mortality in relation to age composition, time trends, and regions. Age determination was based on the analysis of incremental cementum lines in teeth. Major causes of mortality of otters were traffic accidents (69.9%), followed by natural deaths (6.6%), deaths in fish‐traps (6%), hunting (4.1%), and other violent events (4.4%). No significant differences in mortality structure between the sexes were found. Resulting from a log‐linear and a contrast analysis, significant differences in frequencies of mortality causes in relation to different time periods, regions and age classes of otters were observed. The frequency of otters dying from hunting or diseases was highest in youngest (AC I) and oldest (AC V) otters. Generally, the greatest differences between age classes resulted from comparison of frequencies of traffic‐mortality, hunting, and fish‐traps. Concerning time trends, the greatest differences were found in the periods before and after 1990. In addition to the increase of traffic‐mortality, hunting and deaths in fish‐traps influenced the distribution of mortality in different time periods. In eastern Germany, there is a clear difference in mortality between northern and southern regions. This results mainly from commercial fish‐trapping being more common at the northern coast and lakes. However, in all different subsamples of time, region or age‐class, traffic‐killed otters amounted to >50% of all otters found dead.
Divergence of dialects in a linguistic laboratory near the
Belgian–Dutch–German border: Similar dialects
under the influence of different standard languages
Authors: Gerritsen Marinel
Published: July 2002

This article deals with divergence on the lexical,
phonological, and morphological levels in three dialects
that were the same until the mid-20th century (Maaseiks
in Belgium, Susters in the Netherlands, and Waldfeuchts
in Germany) and that have changed under the influence of
three different standard languages (Belgian Dutch, Netherlandic
Dutch, and Standard German). The investigation is carried
out among girls aged 14 to 16 years and women aged 35 to
50 years. Due to the unique laboratory-like situation,
it was possible to gain a detailed understanding of the
role of the structure of the dialect and the dialect–standard
language situation in the process of dialect change under
the influence of a standard language. The data indicate
that the linguistic route of the change is largely the
same for all dialects. This means that the receiving dialect
plays an important part in the linguistic embedding of
a change. However, the rationale of the linguistic road
is still far from clear. The divergence of the similar
dialects occurred relatively recently. Whereas the women
of the three places use the old dialect forms almost exclusively,
the girls use forms of the standard languages or “mixed”
forms, especially in Waldfeucht. The dialect of Waldfeucht
is clearly affected much more strongly by Standard German
than are the dialect of Maaseik by Belgian Dutch and the
dialect of Susteren by Netherlandic Dutch. This can be
explained by a number of factors: the position of the dialect
at school, comprehensibility of the dialect, attitude towards
the dialect, and the use of the dialect.
Older people in A&E: Literature review and implications for British policy and practice
Authors: Bridges Jackie , Spilsbury Karen , Meyer Julienne , Crouch Robert
Published: July 2002

As the proportion of older people in the population rises, health services must continue to develop to meet their special needs. This includes accident and emergency (A&E) services which work at the interface between primary and secondary health care for individuals of all ages. This literature review aimed to answer the following questions:

1) What are the characteristics and special needs of older people in A&E?

2) Which of the current literature describes, evaluates or advocates service initiatives aimed at meeting the needs of older people in A&E?

3) What are the policy implications of the literature reviewed for British A&E services?
Comparing endemism and habitat restriction in Mesoamerican tropical deciduous forest birds: implications for biodiversity conservation planning
Authors: Gordon Caleb E. , Ornelas Juan Francisco
Published: July 2002

Biogeographical endemism and habitat restriction are two easily measured quantities that can be used as indicators of species' ecological restrictions. We analysed and compared these two types of information from available literature sources in an attempt to identify all bird species critically dependent on tropical deciduous forests of western Mexico and Central America. Based on patterns of biogeographical restriction, we identified 42 endemics, 33 disjunct endemics, 59 corridor species and 3 seasonal endemics associated with tropical deciduous forest (TDF) in this region. Based on patterns of habitat use in these species, we classified them as 50 tropical deciduous forest-restricted species and 82 apparent habitat generalist species. No habitat use information was available within the TDF belt for five of the biogeographically restricted species. We found a high proportion of apparent habitat generalists (60%) among biogeographically restricted species. We discuss three specific scenarios in which species critically dependent on TDF may nonetheless appear generalized in their patterns of habitat use. These species are termed “cryptic habitat specialists.” The proportion of apparent habitat generalists is highly variable among biogeographical regions and habitat types. Thus, global biodiversity conservation prioritizations that rely on habitat restriction as an indicator of ecological sensitivity may underestimate conservation needs within bioregions that contain high proportions of cryptic habitat specialists.
Eagle Owl Bubo bubo and power line interactions in the Italian Alps
Authors: Rubolini Diego , Bassi Enrico , Bogliani Giuseppe , Galeotti Paolo , Garavaglia Roberto
Published: July 2002

We reviewed the importance of power lines as a cause of mortality for Eagle Owl in the Italian Alps. Power lines were the most important cause of unnatural mortality for this species, accounting for over 50% of recorded casualties. The number of reported dead owls tended to be higher in September–October, suggesting an influence on juvenile dispersal. Furthermore, the significance of power lines as a cause of mortality increased over time, being lower in the 1960–1980 period than in 1981–1999. Electrocution, which usually takes place at medium-voltage (15–30 kV) electricity poles, accounted for the vast majority of casualties. We suggest some protective measures that may be put into practice in the proximity of Eagle Owl breeding territories.
Spaces of maximal points
Authors: LAWSON JIMMIE
Published: July 2002

This paper shows that it is precisely the complete metrizable
separable metric spaces that
can be realized as the set of maximal points of an ω-continuous dcpo,
where the set of
maximal points is topologized with the relative Scott topology.
RELATIONSHIP OF THE ORDER APIALES TO SUBCLASS ASTERIDAE: A RE-EVALUATION OF MORPHOLOGICAL CHARACTERS BASED ON INSIGHTS FROM MOLECULAR DATA
Authors: PLUNKETT G. M.
Published: July 2002

Phylogenetic relationships involving the angiosperm order Apiales (Apiaceae and Araliaceae) are troublesome at nearly every taxonomic level and have eluded several generations of botanists. Because of difficulties in interpreting and polarizing morphological character states at deeper phylogenetic levels, most studies in Apiales have focused on relationships between the two families and among/within the apialean genera. In the present study, however, recent contributions from molecular analyses are reviewed and combined using a ‘supertree’ approach to test traditional hypotheses of relationships involving Apiales, and to re-evaluate assumptions of character-state evolution in the order. Results from this study confirm that Apiales form a monophyletic group with Pittosporaceae (along with Griselinia G. Forst., Melanophylla Baker, Torricellia DC. and Aralidium Miq.), and should be transferred out of subclass Rosidae (away from both Cornales and Sapindales) to the Asteridae (in a position close to Asterales and Dipsacales). These findings are also supported by several lines of morphological, anatomical, and phytochemical evidence, and provide a more satisfactory framework for interpreting relationships and character-state evolution within the major clades of Apiales.
The Internet, Confidentiality, and the Pharmacy.coms
Authors: HAZLET THOMAS K. , BACH MARY H.M.
Published: July 2002

The advent of the Internet has had a significant
impact on the formation of an information-driven, rapid-paced
society. The number of Internet users reached 50 million
in only five years compared to 13 years for television
and 38 years for radio. Consumer expectation for access,
convenience, and speed has made the cyberspace superhighway
a medium for knowledge exchange and for e-commerce.
The Internet offers a wide variety of health services and
products to healthcare professionals as well as to the
public. Online pharmaceutical sales are predicted to reach
$20–25 billion over the next four years. This is
a dramatic increase when compared to the $1.9 billion in
1999. At the click of the mouse, medications can be ordered
and delivered conveniently to your door. Yet, consumer
discomfort with the security of information provided via
the Internet is growing, and recent incidents involving
disclosure of healthcare information serve to heighten this
concern.
Henry Spira's Search for Common Ground on Animal Testing
Authors: SINGER PETER
Published: July 2002

Since the 1940s the Draize test had been the standard
test applied to any substance that might conceivably get
into a human eye. The Draize test involved immobilizing
fully conscious rabbits in stocks so that they could not
scratch their eyes, and then applying the substance to
one eyeball of each rabbit. The eyeballs were examined
at intervals of, for example, 24, 48, and 72 hours, and
graded for damage such as blindness or blistering. In 1980
Henry Spira launched a campaign against the Draize test.
By taking out full-page ads asking Revlon why it was blinding
rabbits for the sake of beauty, he persuaded that company
to donate $750,000, over 3 years, to a search for alternatives
to the Draize test. Other leading cosmetics corporations
soon followed suit. By 1982 there were signs that progress
was being made. In July of that year Revlon reported that
it had established a panel to ensure that unnecessary Draize
tests are not performed, and as a result it had cut back
the number of rabbits it used annually in the Draize test
from 2,210 in 1979 to 1,431 in 1981. Avon adopted a policy
of always using local anaesthetics if there was any anticipated
discomfort for the animals. Bristol-Myers said that it
was using fewer animals than had been used in the classical
Draize test. All three of the companies were continuing
to contribute substantial sums to research programs designed
to find alternatives to the Draize test.
A Note on Vertex List Colouring
Authors: HAXELL P. E.
Published: July 2002

Let k be a positive integer and let G be a graph. Suppose a list S(v)
of positive integers is assigned to each vertex v, such that

(1) [mid ]S(v)[mid ] = 2k for each vertex v of G, and

(2) for each vertex v, and each c ∈ S(v), the
number of neighbours w of v for which c ∈ S(w) is at most k.

Then we prove that there exists a proper vertex colouring f of G such that
f(v) ∈ S(v) for each v ∈ V(G).
This proves a weak version of a conjecture of Reed.
On the Critical Value for ‘Percolation’ of
Minimum-Weight Trees in the Mean-Field Distance Model
Authors: ALDOUS DAVID
Published: July 2002

Consider the complete n-graph with independent exponential
(mean n)
edge-weights. Let M(c, n) be the maximal size
of subtree for which the
average edge-weight is at most c. It is
shown that M(c, n) makes the transition from
o(n) to
Ω(n) around some critical value c(0),
which can be specified in terms of a fixed point of a mapping on probability
distributions.
Oxygen free radicals and disorders of pregnancy
Authors: Buhimschi Irina A , Weiner Carl P
Published: July 2002

Oxygen radicals and reactive oxygen species are normal attributes of aerobic life. In most molecules, the electrons are paired and, with the exception of hydrogen, the four outer most pairs of each atom form chemical bonds. Electrons are in a relatively stable energy state when paired. A free radical is a molecule with an unpaired electron. Free radicals of oxygen are of particular importance to living organisms in which they are involved in the genesis of a wide array of diseases and physiological processes (e.g. life span and ageing).
Maternal smoking and congenital malformations
Authors: Källén Karin
Published: July 2002

Since the first report by Simpson (1957) of the association between premature birth and maternal smoking, the research on the consequences of maternal smoking during pregnancy on perinatal outcome has been intense. Even if some of the findings have been contradictory, it is now evident that maternal smoking is associated with pre-term birth and low birth weight, low birth weight for gestational age, small head circumference, low Apgar score at 5 min, stillbirth and neonatal death.
Apoptosis in the early bovine embryo
Authors: Matwee Christie , Betts Dean H. , King W. Allan
Published: July 2002

Cell death occurs during early development in vivo and in vitro, although little is known about the mechanism of blastomere death and the relation to embryonic loss. Apoptosis, characterised by chromatin condensation, DNA fragmentation and membrane blebbing, occurs without damage to surrounding cells in contrast to necrosis. Bovine oocytes and in vitro fertilised embryos (total n = 449) were analysed for (1) DNA fragmentation using terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) and (2) morphological features of apoptosis. TUNEL labelling was detected in immature and mature oocytes (7%, n = 57 and 23%, n = 60, respectively), and at least one cell of 8- to 16-cell embryos (5%, n = 57), morulae/early blastocysts (79%, n = 39) and expanded/hatched blastocysts (100%, n = 48). In contrast, TUNEL labelling was not detected in zygotes (n = 61), 2-cell embryos (n = 46) or 3- to 7-cell embryos (n = 81). Chromatin condensation, nuclear fragmentation, absence of neighbouring cell destruction and extrusion of cells was frequent among advanced stage embryos. Although not detected during early cleavage under standard conditions, TUNEL labelling indicative of apoptosis was induced by treatment with 10 μM staurosporine for 30 h in 95% of cleavage stage embryos (n = 59). Determination of the expression and localisation of the p53 tumour suppressor gene using reverse transcription polymerase chain reaction and whole-mount immunofluorescence revealed that although p53 transcripts were present throughout early development, nuclear localisation of p53 protein could not be detected in any blastocyst suggesting p53-independent apoptosis. This study has shown that apoptosis is dependent on embryonic developmental stage after standard culture. This suggests that bovine embryos become more capable of accommodating damaged or abnormal cells as development proceeds.
Cortical granule exocytosis in Bufo arenarum oocytes matured in vitro
Authors: Oterino J. , Sánchez Toranzo G. , Zelarayán L. , Valz-Gianinet J.N. , Bühler M.I.
Published: July 2002

Denuded Bufo arenarum oocytes matured in vitro by progesterone treatment exhibited abnormal segmentation due to the penetration of more than one sperm. These oocytes were able to respond to activation stimuli and exhibited the external signs characteristic of activation. However, the prevention of polyspermy was not effective in these oocytes, which exhibited numerous sperm in their cytoplasm. The aim of this work was to analyse the cortical reaction in polyspermic Bufo arenarum oocytes matured in vitro. The result indicate that the cortical reaction of these oocytes seems to occur with a chronological sequence similar to that described for ovoposited oocytes of this species. In addition, when, 1 min after pricking, cortical granule exocytosis occurred, the oocytes became refractory to sperm entry, suggesting that they are able to establish a slow block to polyspermy.
Effects of follicle-stimulating hormone, bovine somototrophin and okadaic acid on cumulus expansion and nuclear maturation of Blue fox (Alopex lagopus) oocytes in vitro
Authors: Sršeň Vlastimil , Kalous Jaroslav , Nagyova Eva , šutovský Peter , King W. Allan , Motlik Jan
Published: July 2002

The meiotic competence and meiosis resumption of Blue fox (Alopex lagopus) oocytes from anoestrous animals were followed. Oocyte–cumulus complexes (OCC) were cultured in modified TC 199 medium with or without FSH, recombinant bovine somatotrophin (bST) and okadaic acid (OA). The results showed that oocytes less than 100 μm in diameter did not achieve germinal vesicle breakdown (GFBD) by 72 h of culture, which indicates their meiotic incompetence. Oocytes larger than 100 µm in diameter underwent GVBD after 48 h of culture (27%) and reached metaphase II (MII) after 72 and 96 h (20% and 27%) in control medium. Both bST and OA accelerated resumption of meiosis (bST: 55% GVBD and 42% MII after 48 h; OA: 66% GVBD after 18 h). In contrast, FSH significantly reduced meiosis resumption (only 3% GVBD and MII after 72 h) and induced changes in the shape of cumulus granulosa (CG) cells and F-actin assembly typical for cumulus expansion. However, the innermost layers of CG cells (corona radiata) remained connected with the oocyte via gap junctions until the end of culture. Cumuli of oocytes cultured in control, bST-supplemented or OA-supplemented medium did not expand (changes in cell shape and F-actin redistribution did not occur). Moreover, especially in media with bST and OA an increased detachment and rapid disconnection of their gap junctions with the oocyte were observed. These results suggest that under in vitro conditions FSH stimulates expansion of the CG cells and the attached membrana granulosa cells but in contrast it secures heterologous gap junctions between cytoplasmic processes of the corona radiata cells and oolemma during 3 days of culture. Thus, in agreement with the in vivo situation in which Canidae oocytes are ovulated in the GV stage, the cumulus, mainly corona radiata cells, controls resumption of meiosis in Blue fox oocytes under in vitro conditions also.
NEW WOMEN, OLD AND NEW
Authors: Mitchell Sally
Published: July 2002

DESPITE SOME TWENTY YEARS of scholarship in the field, core questions such as “what is a New Woman?” and “what is New Woman fiction?” still remain vexed and all too often need more precise definition. Yet one can say that for all the conflicts of meaning and emphasis between sexual and political, discursive and actual, or caricature and didactic, the feminist rediscovery of the New Woman during the late 1970s has not only opened the canon but has also begun a transformation in the way we understand the entire fin de siècle.
Democracy in the 21st century: can we be optimistic?
Authors: LIJPHART AREND
Published: July 2002

The prospects for the spread of democracy around the world in the 21st century appear to be bright, but there are also important reasons for pessimism. One is that politicians and constitution-writers in the democracies are not aware of, or choose to ignore, compelling social science evidence concerning the superiority of parliamentary systems of government and proportional representation (in contrast to presidential government and majoritarian electoral systems). The older democracies are not in danger of failing, but they are losing much of their democratic vitality, as seen in the decline of people's interest in politics, decreasing voter participation, and the serious weakening of political parties. For these problems, too, parliamentarism and proportional representation are at least partial remedies, but stronger measures (such as compulsory voting) also deserve to be considered seriously
Analyses for elucidating current question
answering technology
Authors: LIGHT MARC , MANN GIDEON S. , RILOFF ELLEN , BRECK ERIC
Published: July 2002

In this paper, we take a detailed look at the performance of components of an idealized
question answering system on two different tasks: the TREC Question Answering task
and a set of reading comprehension exams. We carry out three types of analysis: inherent
properties of the data, feature analysis, and performance bounds. Based on these analyses
we explain some of the performance results of the current generation of Q/A systems and
make predictions on future work. In particular, we present four findings: (1) Q/A system
performance is correlated with answer repetition; (2) relative overlap scores are more effective
than absolute overlap scores; (3) equivalence classes on scoring functions can be used to
quantify performance bounds; and (4) perfect answer typing still leaves a great deal of
ambiguity for a Q/A system because sentences often contain several items of the same type.
ANGER CONTROL FOR PEOPLE WITH LEARNING DISABILITIES: A CRITICAL REVIEW
Authors: Whitaker Simon
Published: July 2002

The literature on the use of cognitively based anger control packages of treatment for people with learning
disabilities is reviewed. It is found that the experimental evidence for the effectiveness of such treatment is weak.
There is, however, good evidence that two of the components of the package, relaxation and self-monitoring, can be
effective in their own right, with relaxation being found to reduce anger and self-monitoring to reduce other challenging
behaviours. The use of cognitive procedures with people who have learning disabilities is discussed.
A Text for the Well-Rounded Practitioner
Authors: Pachana Nancy A.
Published: July 2002

As individuals gain expertise in a chosen field they
can begin to conceptualize how what they know can be applied
more broadly, to new populations and situations, or to increase
desirable outcomes. Judd's book does just this. It takes
our current understanding of the etiology, course, and sequelae
of brain injuries, combines this with established psychotherapy
and rehabilitation techniques, and expands these into a cogent
model of what Judd calls “neuropsychotherapy.” Simply
put, neuropsychotherapy attempts to address the cognitive,
emotional and behavioral changes in brain-injured persons, changes
that may go undiagnosed, misdiagnosed, or untreated.
Optimal soil depletion with output and price uncertainty
Authors: GREPPERUD SVERRE
Published: July 2002

This paper studies soil depletion incentives in a dynamic economic model under two different sources of revenue uncertainty (output and price risk). The focus is on the long-term effects of risk-averse preferences when farming decisions have implications for both expected short-run production and natural topsoil fertility. The analysis shows that the risk properties of the stock variable are crucial for the results arrived. The presence of risk preferences is found to improve soil conservation incentives in a low-input farming system, independent of the source of revenue risk considered. The only case for which soil conservation incentives are weakened is for high-input farming systems under price uncertainty.

JEL classification: Q12, Q20, D81
How to substitute in order to sustain: knowledge driven growth under environmental restrictions
Authors: BRETSCHGER LUCAS
Published: July 2002

This paper presents different substitution mechanisms which determine, in a theoretical framework, the conditions for long-term sustainable development. In a one-sector approach and in two versions of a multi-sector endogenous growth model, the accumulation and the substitution of man-made inputs for natural resources are analysed. Assuming man-made capital to be an output of a specific sector of the economy, the elasticities of substitution between the different inputs play a more complex role than suggested by the one-sector approach. According to the multi-sector models, the prediction of growth becoming sustainable emerges as realistic, provided that the sectoral adjustment costs in the economy are not too high.
Loop-interpolation-random & gesture: déjà vu in computer-aided composition
Authors: FERRAZ SILVIO , ALDROVANDI LEONARDO
Published: July 2002

Starting from a distinction between music creation and sound or
pre-established methods of form and sound manipulation, this paper discusses
the use of some typical procedures in computer-aided composition. A
critique of common-sense procedures sets out to show that musical creativity
may be threatened and put at risk in the name of a community's immediate
acceptance of what is considered to be of musical value.
Attention-Deficit Hyperactivity Disorder: How Much Do We See?
Authors: Keen Daphne , Bramble David , Olurin-Lynch Jacqueline
Published: July 2002

A postal questionnaire survey of senior clinical psychologists, child
psychiatrists and community paediatricians in the Trent region (85%
response) revealed that a total of 826 new ADHD cases were seen over the
index period, 1997–1998. Approximately a third of these were adolescents.
Wide variations in individuals' clinical caseloads, both within and between
professional groups, were revealed. No respondent could identify any local
formal transitional arrangements or adult services for older ADHD cases.
This would suggest that there is a pressing need to establish such services
for patients with ADHD irrespective of their age.
Cell surface proteins Nasrat and Polehole stabilize the Torso-like extracellular determinant in Drosophila oogenesis
Authors: Jiménez Gerardo , González-Reyes Acaimo , Casanova Jordi
Published: July 2002

Structural cell-surface and extracellular-matrix proteins modulate intercellular signaling events during development, but how this is achieved remains largely unknown. Here we identify a novel family ofDrosophila proteins, Nasrat and Polehole, that coat the oocyte surface and play two roles: They mediate assembly of the eggshell, and act in the Torso RTK signaling pathway that specifies the terminal regions of the embryo. Nasrat and Polehole are essential for extracellular accumulation of Torso-like, a factor secreted during oogenesis that initiates Torso receptor activation. Stabilization of secreted factors by specialized pericellular proteins may be a general mechanism during signaling and developmental patterning.
Targeting of Ikaros to pericentromeric heterochromatin by direct DNA binding
Authors: Cobb Bradley S. , Morales-Alcelay Susana , Kleiger Gary , Brown Karen E. , Fisher Amanda G. , Smale Stephen T.
Published: July 2002

Ikaros is a sequence-specific DNA-binding protein that is essential for lymphocyte development. Little is known about the molecular function of Ikaros, although recent results have led to the hypothesis that it recruits genes destined for heritable inactivation to foci containing pericentromeric heterochromatin. To gain further insight into the functions of Ikaros, we have examined the mechanism by which it is targeted to centromeric foci. Efficient targeting of Ikaros was observed upon ectopic expression in 3T3 fibroblasts, demonstrating that lymphocyte-specific proteins and a lymphoid nuclear architecture are not required. Pericentromeric targeting did not result from an interaction with the Mi-2 remodeling factor, as only a small percentage of Mi-2 localized to centromeric foci in 3T3 cells. Rather, targeting was dependent on the amino-terminal DNA-binding zinc finger domain and carboxy-terminal dimerization domain of Ikaros. The carboxy-terminal domain was required only for homodimerization, as targeting was restored when this domain was replaced with a leucine zipper. Surprisingly, a detailed substitution mutant analysis of the amino-terminal domain revealed a close correlation between DNA-binding and pericentromeric targeting. These results show that DNA binding is essential for the pericentromeric localization of Ikaros, perhaps consistent with the presence of Ikaros binding sites within centromeric DNA repeats. Models for the function of Ikaros that are consistent with this targeting mechanism are discussed.
SNP Profile within the Human Major Histocompatibility Complex Reveals an Extreme and Interrupted Level of Nucleotide Diversity
Authors: Gaudieri Silvana , Dawkins Roger L. , Habara Kaori , Kulski Jerzy K. , Gojobori Takashi
Published: July 2002

The human major histocompatibility complex (MHC) is characterized by polymorphic multicopy gene families, such as HLA and MIC (PERB11); duplications; insertions and deletions (indels); and uneven rates of recombination. Polymorphisms at the antigen recognition sites of the HLA class I and II genes and at associated neutral sites have been attributed to balancing selection and a hitchhiking effect, respectively. We, and others, have previously shown that nucleotide diversity between MHC haplotypes at non-HLA sites is unusually high (>10%) and up to several times greater than elsewhere in the genome (0.08%–0.2%). We report here the most extensive analysis of nucleotide diversity within a continuous sequence in the genome. We constructed a single nucleotide polymorphism (SNP) profile that reveals a pattern of extreme but interrupted levels of nucleotide diversity by comparing a continuous sequence within haplotypes in three genomic subregions of the MHC. A comparison of several haplotypes within one of the genomic subregions containing the HLA-B and -C loci suggests that positive selection is operating over the whole subgenomic region, including HLA and non-HLA genes.

[The sequence data for the multiple haplotype comparisons within the class I region have been submitted to DDBJ/EMBL/GenBank under accession nos. AF029061, AF029062, and AB031005–AB031010. Additional sequence data have been submitted to the DDBJ data library under accession nos.AB031005–AB03101 and AF029061–AF029062.]
High-Performance Multiplex SNP Analysis of Three Hemochromatosis-Related Mutations With Capillary Array Electrophoresis Microplates
Authors: Medintz Igor , Wong Wendy W. , Berti Lorenzo , Shiow Lawrence , Tom Jennifer , Scherer James , Sensabaugh George , Mathies Richard A.
Published: July 2002

An assay is described for high-throughput single nucleotide polymorphism (SNP) genotyping on a microfabricated capillary array electrophoresis (CAE) microchip. The assay targets the three common variants at the HFE locus associated with the genetic disease hereditary hemochromatosis (HHC). The assay employs allele-specific PCR (ASPCR) for the C282Y (845g->a), H63D (187c->g), and S65C (193a->t) variants using fluorescently-labeled energy-transfer (ET) allele-specific primers. Using a 96-channel radial CAE microplate, the labeled ASPCR products generated from 96 samples in a reference Caucasian population are simultaneously separated with single-base-pair resolution and genotyped in under 10 min. Detection is accomplished with a laser-excited rotary four-color fluorescence scanner. The allele-specific amplicons are differentiated on the basis of both their size and the color of the label emission. This study is the first demonstration of the combined use of ASPCR with ET primers and microfabricated radial CAE microplates to perform multiplex SNP analyses in a clinically relevant population.
Orphanin FQ Suppresses NMDA Receptor-Dependent Long-Term Depression and Depotentiation in Hippocampal Dentate Gyrus
Authors: Wei Wei-Zheng , Xie Cui-Wei
Published: July 2002

We reported previously that orphanin FQ (OFQ) inhibited NMDA receptor-mediated synaptic currents and consequently suppressed induction of long-term potentiation (LTP) in the hippocampal dentate gyrus. This study examines the effect of OFQ on several other forms of long-term synaptic plasticity in the lateral perforant path of mouse hippocampal dentate gyrus. (1) Long-term depression (LTD): a low frequency stimulation (1 Hz, 15 min) applied to the lateral perforant path induced a long-lasting reduction in the dentate field potentials in slices from 22- to 30-day-old mice. This LTD was sensitive to the NMDA receptor blocker D-AP5, and could be significantly attenuated by bath application of OFQ (1 μm, 25 min). (2) Primed LTD: induction of LTD in slices from 50- to 65-day-old mice required a priming procedure consisting of multiple high frequency stimulus trains delivered in the presence of D-AP5 before the low-frequency stimulation. OFQ applied during the low-frequency stimulation, but not during the priming trains, blocked induction of primed LTD. (3) Depotentiation: high-frequency train-induced dentate LTP could be reversed by a subsequent low-frequency stimulation. This depotentiation was also attenuated by either OFQ or D-AP5 applied during low-frequency stimulation. These results, together with our previous findings, suggest that OFQ inhibits bidirectional changes in synaptic strength in the dentate; and its multiple actions on NMDA receptor-dependent, long-term synaptic plasticity might work in tandem to regulate hippocampus-dependent learning and memory.
Modulation of Cyclin Transcript Levels in Cultured Cells of Arabidopsis thaliana
Authors: Fuerst RAUA. , Soni R. , Murray JAH. , Lindsey K.
Published: July 2002

Previous studies on the cell cycle of Arabidopsis thaliana have been hindered by the lack of synchronous cell culture systems. We have used liquid callus cultures and a cycloheximide-synchronized suspension culture of Arabidopsis to investigate changes in cyclin transcript levels in response to exogenous auxin, cytokinin, and nutrients, and during the cell cycle. CYCD1 ([delta]1) transcript was virtually undetectable in liquid-cultured callus or suspension-culture cells. CYCD2 ([delta]2) transcript levels were largely unaffected by the readdition of phytohormones or nitrate to the growth medium, and remained constant throughout the cell cycle in suspension-culture cells. CYCD3 ([delta]3) transcript levels were strongly dependent on nitrate, and were induced at the G1/S transition following phytohormone readdition. In synchronized suspension-culture cells, CYCD3 transcript accumulated during the S phase, and remained constant thereafter. These results support the hypothesis that D cyclins function as part of the cellular machinery that integrates diverse signals impinging upon commitment to cell division. In synchronized cells transcripts of the mitotic cyclins CYC1, CYC2, and CYC3 reached a maximum with peak mitotic index, but CYC3 transcript levels increased earlier than those of CYC1 or CYC2. The kinetics of accumulation of CYC transcript levels support their classification as A-type (CYC3) and B-type (CYC1 and CYC2) cyclins, respectively.
Differential Expression of the Multigene Family Encoding the Soybean Mitochondrial Alternative Oxidase
Authors: Finnegan P. M. , Whelan J. , Millar A. H. , Zhang Q. , Smith M. K. , Wiskich J. T. , Day D. A.
Published: July 2002

The alternative oxidase (AOX) of the soybean (Glycine max L.) inner mitochondrial membrane is encoded by a multigene family (Aox) with three known members. Here, the Aox2 and Aox3 primary translation products, deduced from cDNA analysis, were found to be 38.1 and 36.4 kD, respectively. Direct N-terminal sequencing of partially purified AOX from cotyledons demonstrates that the mature proteins are 31.8 and 31.6 kD, respectively, implying that processing occurs upon import of these proteins into the mitochondrion. Sequence comparisons show that the processing of plant AOX proteins occurs at a characteristic site and that the AOX2 and AOX3 proteins are more similar to one another than to other AOX proteins, including soybean AOX1. Transcript analysis using a polymerase chain reaction-based assay in conjunction with immunoblot experiments indicates that soybean Aox genes are differentially expressed in a tissue-dependent manner. Moreover, the relative abundance of both Aox2 transcripts and protein in cotyledons increase upon greening of dark-grown seedlings. These results comprehensively explain the multiple AOX-banding patterns observed on immunoblots of mitochondrial proteins isolated from various soybean tissues by matching protein bands with gene products.
Sex Determination in Dioecious Silene Iatifolia (Effects of the Y Chromosome and the Parasitic Smut Fungus (Ustilago violacea) on Gene Expression during Flower Development)
Authors: Scutt C. P. , Li Y. , Robertson S. E. , Willis M. E. , Gilmartin P. M.
Published: July 2002

We have embarked on a molecular cloning approach to the investigation of sex determination in Silene Iatifolia Poiret, a dioecious plant species with morphologically distinguishable sex chromosomes. One of our key objectives was to define a range of genes that are up-regulated in male plants in response to Y chromosome sex-determination genes. Here we present the characterization of eight male-specific cDNA sequences and classify these according to their expression dynamics to provide a range of molecular markers for dioecious male flower development. Genetically female S. latifolia plants undergo a partial sex reversal in response to infection by the parasitic smut fungus Ustilago violacea. This phenomenon has been exploited in these studies; male-specific cDNAs have been further categorized as inducible or noninducible in female plants by smut fungus infection. Analysis of the organ-specific expression of male-specific probes in male and female flowers has also identified a gene that is regulated in a sex-specific manner in nonreproductive floral tissues common to both male and female plants. This observation provides, to our knowledge, the first molecular marker for dominant effects of the Y chromosome in nonreproductive floral organs.
Rapid and Transient Induction of a Parsley Microsomal [delta]12 Fatty Acid Desaturase mRNA by Fungal Elicitor
Authors: Kirsch C. , Hahlbrock K. , Somssich I. E.
Published: July 2002

Treatment of cultured parsley (Petroselinum crispum L.) cells with a structurally defined peptide elicitor (Pep25) of fungal origin has previously been shown to cause rapid and large changes in the levels of various desaturated fatty acids. We isolated two distinct parsley cDNAs sharing high sequence similarity with microsomal [omega]-6 fatty acid desaturases (FADs). One of them was functionally identified as a [delta]12 FAD by expression in the yeast Saccharomyces cerevisiae. Two dienoic fatty acids, hexadecadienoic and linoleic, which were not detectable in control cells, together constituted up to 12% of the total fatty acids in the transformed yeast cells. [delta]12 FAD mRNA accumulated rapidly and transiently in elicitor-treated parsley cells, protoplasts, and leaves. These and previous results indicate that fatty acid desaturation is an important early component of the complex defense response of parsley to attempted fungal infection.
Purification and Characterization of a Galactose-Rich Basic Glycoprotein in Tobacco1
Authors: Takeichi Tetsuo , Takeuchi Junko , Kaneko Takako , Kawasaki Shinji
Published: July 2002

We found a galactose-rich basic glycoprotein (GBGP) in the cell walls of cultured tobacco (Nicotiana tabacum) cells. GBGP and extensin were isolated as the major components of basic, salt-extracted cell wall glycoproteins. GBGP and extensin were separated by gel filtration in 6 m guanidine hydrochloride as 49- and 90-kD peaks, respectively, and further purified with reverse-phase chromatography. The protein moiety of GBGP constitutes about one-half of the molecule (w/w) and contains lysine (16%), proline (12%), hydroxyproline (10%), tyrosine (4%), alanine (7%), leucine (6%), and cystine (1.4%). Galactose accounted for 72% of the sugar moiety, arabinose content was low (17%), and a significant amount of mannose (7%) was found. No immunological cross-reaction was detected between GBGP and extensin. The antibody against native GBGP with sugar chains reacted with other glycoproteins on the gel blots, whereas the antibodies against deglycosylated GBGP and native extensin were highly specific. Immunolocalization analysis in tobacco stems showed that GBGP is specific to parenchyma tissue and that extensin localizes in the epidermis. This tissue-specific and exclusive distribution suggests important functions of these basic glycoproteins.
Overexpression of Nitrate Reductase in Tobacco Delays Drought-Induced Decreases in Nitrate Reductase Activity and mRNA1
Authors: Ferrario-Méry Sylvie , Valadier Marie-Hélène , Foyer Christine H.
Published: July 2002

Transformed (cauliflower mosaic virus 35S promoter [35S]) tobacco (Nicotiana plumbaginifoliaL.) plants constitutively expressing nitrate reductase (NR) and untransformed controls were subjected to drought for 5 d. Drought-induced changes in biomass accumulation and photosynthesis were comparable in both lines of plants. After 4 d of water deprivation, a large increase in the ratio of shoot dry weight to fresh weight was observed, together with a decrease in the rate of photosynthetic CO2 assimilation. Foliar sucrose increased in both lines during water stress, but hexoses increased only in leaves from untransformed controls. Foliar NO3−decreased rapidly in both lines and was halved within 2 d of the onset of water deprivation. Total foliar amino acids decreased in leaves of both lines following water deprivation. After 4 d of water deprivation no NR activity could be detected in leaves of untransformed plants, whereas about 50% of the original activity remained in the leaves of the 35S-NR transformants. NR mRNA was much more stable than NR activity. NR mRNA abundance increased in the leaves of the 35S-NR plants and remained constant in controls for the first 3 d of drought. On the 4th d, however, NR mRNA suddenly decreased in both lines. Rehydration at d 3 caused rapid recovery (within 24 h) of 35S-NR transcripts, but no recovery was observed in the controls. The phosphorylation state of the protein was unchanged by long-term drought. There was a strong correlation between maximal extractable NR activity and ambient photosynthesis in both lines. We conclude that drought first causes increased NR protein turnover and then accelerates NR mRNA turnover. Constitutive NR expression temporarily delayed drought-induced losses in NR activity. 35S-NR expression may therefore allow more rapid recovery of N assimilation following short-term water deficit.
A New Class of Arabidopsis Mutants with Reduced Hexadecatrienoic Acid Fatty Acid Levels1
Authors: Miquel Martine , Cassagne Claude , Browse John
Published: July 2002

Chloroplast glycerolipids in a number of higher-plant species, including Arabidopsis thaliana, are synthesized by two distinct pathways termed the prokaryotic and eukaryotic pathways. The molecules of galactolipids produced by the prokaryotic pathway contain substantial amounts of hexadecatrienoic acid fatty acid. Here we describe a new class of mutants, designatedgly1, with reduced levels of hexadecatrienoic acid. Lipid fatty acid profiles indicated that gly1 mutants exhibited a reduced carbon flux through the prokaryotic pathway that was compensated for by an increased carbon flux through the eukaryotic pathway. Genetic and biochemical approaches revealed that thegly1 phenotype could not be explained by a deficiency in the enzymes of the prokaryotic pathway. The flux of fatty acids into the prokaryotic pathway is sensitive to changes in glycerol-3-phosphate (G3P) availability, and the chloroplast G3P pool can be increased by exogenous application of glycerol to leaves. Exogenous glycerol treatment of gly1 plants allowed chemical complementation of the mutant phenotype. These results are consistent with a mutant lesion affecting the G3P supply within the chloroplast. The gly1 mutants may therefore help in determining the pathway for synthesis of chloroplast G3P.
S-Adenosyl-l-Methionine:l-MethionineS-Methyltransferase from Germinating Barley
Authors: João Pimenta Maria , Kaneta Tsuyoshi , Larondelle Yvan , Dohmae Naoshi , Kamiya Yuji
Published: July 2002

S-Adenosyl-l-methionine:l-methionineS-methyltransferase (MMT) catalyzes the synthesis ofS-methyl-l-methionine (SMM) froml-methionine andS-adenosyl-l-methionine. SMM content increases during barley (Hordeum vulgare L.) germination. Elucidating the role of this compound is important from both a fundamental and a technological standpoint, because SMM is the precursor of dimethylsulfide, a biogenic source of atmospheric S and an undesired component in beer. We present a simple purification scheme for the MMT from barley consisting of 10% to 25% polyethylene glycol fractionation, anion-exchange chromatography on diethylaminoethyl-Sepharose, and affinity chromatography on adenosine-agarose. A final activity yield of 23% and a 2765-fold purification factor were obtained. After digestion of the protein with protease, the amino acid sequence of a major peptide was determined and used to produce a synthetic peptide. A polyclonal antibody was raised against this synthetic peptide conjugated to activated keyhole limpet hemocyanin. The antibody recognized the 115-kD denatured MMT protein and native MMT. During barley germination, both the specific activity and the amount of MMT protein increased. MMT-specific activity was found to be higher in the root and shoot than in the endosperm. MMT could be localized by an immunohistochemical approach in the shoot, scutellum, and aleurone cells but not in the root or endosperm (including aleurone).