bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma Membrane Targeting of Podocin Through the Classical Exocytic Pathway: Effect of NPHS2 Mutations
Authors: Roselli Séverine , Moutkine Imane , Gribouval Olivier , Benmerah Alexandre , Antignac Corinne
Published: December 2004

Podocytes are specialized epithelial cells of the glomerulus in the kidney, which interconnect at the top of the glomerular basement membrane through the slit diaphragm, an adherens‐like junction that plays a crucial role in the glomerular filtration process. Podocin, a plasma membrane anchored stomatin‐like protein, is expressed in lipid rafts at the insertion of the slit diaphragm in podocytes. Mutations in NPHS2, the gene encoding podocin, are associated with inherited and sporadic cases of steroid‐resistant nephrotic syndrome. Here, we show that brefeldin A induces accumulation of newly synthesized podocin in the endoplasmic reticulum, suggesting that podocin biosynthesis follows the classical secretory pathway, and we study the effect of 12 NPHS2 mutations associated with steroid‐resistant nephrotic syndrome on the trafficking of the protein. We found that 9 podocin mutants were not targeted to the plasma membrane, 8 being retained in the endoplasmic reticulum and one being localized in late endosomes. Furthermore, by screening our database of patients with NPHS2 mutations, we found that podocin mutants retained in the endoplasmic reticulum are associated with earlier onset of the disease than those correctly targeted to the cell membrane. Our data suggest that most of NPHS2 mutations lead to retention of podocin in the endoplasmic reticulum and therefore provide a rationale for devising therapeutic approaches aimed at correcting the protein processing defect.
The Uroepithelium: Not Just a Passive Barrier
Authors: Apodaca Gerard
Published: December 2004

The uroepithelium lines the inner surface of the renal pelvis, the ureters, and the urinary bladder, where it forms a tight barrier that allows for retention of urine, while preventing the unregulated movement of ions, solutes, and toxic metabolites across the epithelial barrier. In the case of the bladder, the permeability barrier must be maintained even as the organ undergoes cyclical changes in pressure as it fills and empties. Beyond furthering our understanding of barrier function, new analysis of the uroepithelium is providing information about how detergent‐insoluble membrane/protein domains called plaques are formed at the apical plasma membrane of the surface umbrella cells, how mechanical stimuli such as pressure alter exocytic and endocytic traffic in epithelial cells such as umbrella cells, and how changes in pressure are communicated to the underlying nervous system.
Regulatory T cells suppress tumor-specific CD8 T cell cytotoxicity through TGF-β signalsin vivo
Authors: Chen Mei-Ling , Pittet Mikaël J. , Gorelik Leonid , Flavell Richard A. , Weissleder Ralph , von Boehmer Harald , Khazaie Khashayarsha
Published: December 2004

Cancer patients can harbor significant numbers of CD8 and CD4 T cells with specificities to tumor antigens (Ags). Yet, in most cases, such T cells fail to eradicate the tumorin vivo.Here, we investigated the interference of Ag-specific CD4+CD25+regulatory T cells (Treg) with the tumor-specific CD8 T cell immune responsein vivo, by monitoring the homing, expansion, and effector function of both subsets in draining and nondraining lymph nodes. The results show that CD8 cells expand to the same extent and produce similar levels of IFN-γ in the presence or absence of Ag-specific Treg. Nevertheless, these Treg abrogate CD8 T cell-mediated tumor rejection by specifically suppressing the cytotoxicity of expanded CD8 cells. The molecular mechanism of suppression involves TGF-β because expression of a dominant-negative TGF-β receptor by tumor-specific CD8 cells renders them resistant to suppression and is associated with tumor rejection and unimpaired cytotoxicity.
Revisiting quorum sensing: Discovery of additional chemical and biological functions for 3-oxo-
N
-acylhomoserine lactones
Authors: Kaufmann Gunnar F. , Sartorio Rafaella , Lee Sang-Hyeup , Rogers Claude J. , Meijler Michael M. , Moss Jason A. , Clapham Bruce , Brogan Andrew P. , Dickerson Tobin J. , Janda Kim D.
Published: December 2004

Bacteria use small diffusible molecules to exchange information in a process called quorum sensing. An important class of autoinducers used by Gram-negative bacteria is the family of
N
-acylhomoserine lactones. Here, we report the discovery of a previously undescribed nonenzymatically formed product from
N
-(3-oxododecanoyl)-L-homoserine lactone; both the
N
-acylhomoserine and its novel tetramic acid degradation product, 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, are potent antibacterial agents. Bactericidal activity was observed against all tested Gram-positive bacterial strains, whereas no toxicity was seen against Gram-negative bacteria. We propose that
Pseudomonas aeruginosa
utilizes this tetramic acid as an interference strategy to preclude encroachment by competing bacteria. Additionally, we have discovered that this tetramic acid binds iron with comparable affinity to known bacterial siderophores, possibly providing an unrecognized mechanism for iron solubilization. These findings merit new attention such that other previously identified autoinducers be reevaluated for additional biological functions.
Classifying homicide offenders and predicting their characteristics from crime scene behavior
Authors: Santtila Pekka , Häkkänen Helinä , Canter David , Elfgren Thomas
Published: December 2004

A theoretical distinction between instrumental and expressive aggression was used in analyzing offender characteristics and their associations with crime scene actions in Finnish homicides. Twenty‐one variables reflecting the offenders’ criminal activity, previous relationships with intimates and victims, and general social and psychological adjustment were derived from files of single‐offender/single‐victim homicides occurring between 1980 and 1994 (n= 502). Additionally, three variables describing post‐offense actions and police interview behavior were included. A multidimensional scaling procedure was used to investigate the interrelationships between the variables. A distinction between expressive and instrumental characteristics was observable in the empirical structure, which was divided into three subthemes of Instrumental, Expressive: Blood, and Expressive: Intimate. Associations between the characteristics with five previously identified subthemes of crime scene actions were computed. In addition, the subthemes of crime scene actions were related to post‐offense actions and police interview behavior, with Expressive themes being associated with less denial as well as a greater likelihood of surrendering and confession. The practical usefulness for police investigations and theoretical implications of the results are discussed.
Relevance of non‐human animal studies to the understanding of human sexuality
Authors: Ågmo Anders , Ellingsen Ellinor
Published: December 2004

There are several reasons for studying sexual behavior in animals other than the human. Prominent among these is probably the use of sexual behavior as a model system for analyzing hormone actions on the brain. In this kind of study, lordosis behavior in the female rat has frequently been used as the behavioral end‐point. Recently, the mouse has become a popular subject because of the availability of strains lacking estrogen or progesterone receptors. Animal sexual behavior is also studied for its own sake by biologists, by agricultural scientists and by those interested in the management of wildlife resources. Finally, there are some researchers interested in human sexual behavior who prefer to approach their problems through studies in non‐human subjects, as they thereby gain access to techniques of experimentation impossible in human subjects. This is particularly important when the neurobiological basis of sexual behavior is the subject of study. Two striking similarities between humans and other mammals are the hormone dependency of sexual motivation and the fundamentally bisexual organization of the nervous system. In addition, animal studies have revealed how learning with sexual reinforcement can be an important determinant of sexual behavior. The role of learning has been largely ignored in human studies, and this has led to many misconceptions. Paramount among these is the idea that sexual behavior is associated with reproduction.
Integrated OU Processes and Non‐Gaussian OU‐based Stochastic Volatility Models
Authors: Barndorff‐Nielsen Ole E. , Shephard Neil
Published: December 2004

Abstract. In this paper, we study the detailed distributional properties of integrated non‐Gaussian Ornstein–Uhlenbeck (intOU) processes. Both exact and approximate results are given. We emphasize the study of the tail behaviour of the intOU process. Our results have many potential applications in financial economics, as OU processes are used as models of instantaneous variance in stochastic volatility (SV) models. In this case, an intOU process can be regarded as a model of integrated variance. Hence, the tail behaviour of the intOU process will determine the tail behaviour of returns generated by SV models.
A Non‐Gaussian Spatial Process Model for Opacity of Flocculated Paper
Authors: Brown Patrick E. , Diggle Peter J. , Henderson Robin
Published: December 2004

ABSTRACT.  Product quality in the paper‐making industry can be assessed by opacity of a linear trace through continuous production sheets, summarized in spectral form. We adopt a class of non‐Gaussian stochastic models for continuous spatial variation to describe data of this type. The model has flexible covariance structure, physically interpretable parameters and allows several scales of variation for the underlying process. We derive the spectral properties of the model, and develop methods of parameter estimation based on maximum likelihood in the frequency domain. The methods are illustrated using sample data from a UK mill.
Algebraic Markov Bases and MCMC for Two‐Way Contingency Tables
Authors: Rapallo Fabio
Published: December 2004

ABSTRACT.  The Diaconis–Sturmfels algorithm is a method for sampling from conditional distributions, based on the algebraic theory of toric ideals. This algorithm is applied to categorical data analysis through the notion of Markov basis. An application of this algorithm is a non‐parametric Monte Carlo approach to the goodness of fit tests for contingency tables. In this paper, we characterize or compute the Markov bases for some log‐linear models for two‐way contingency tables using techniques from Computational Commutative Algebra, namely Gröbner bases. This applies to a large set of cases including independence, quasi‐independence, symmetry, quasi‐symmetry. Three examples of quasi‐symmetry and quasi‐independence from Fingleton (Models of category counts, Cambridge University Press, Cambridge, 1984) and Agresti (An Introduction to categorical data analysis, Wiley, New York, 1996) illustrate the practical applicability and the relevance of this algebraic methodology.
Admission to Nursing Homes in Taiwan
Authors: Liu Li‐Fan , Tinker Anthea
Published: December 2004

The population of Taiwan is facing a radical ageing process. A proportion of the growing number of people aged 65 and over is expected to need nursing home care. This research concerns the family context of decision‐making in the process of admission to a nursing home in Taiwan. Employing survey data from interviews with elderly people in nursing homes (235 interviews) and their carers/key families (265 interviews), the factors affecting their views about admission were explored. Bivariate analysis and a logistic regression model were also used to examine perceptions of alternatives to nursing home care among family members with elderly relatives in nursing homes. Most elderly people in Taiwan are cared for in their own homes by their families but, in some circumstances, entry to a nursing home seemed inevitable. This research found that the decisions were taken mainly within a family context. The adult children of the elderly people, carers/key families’ preferences and the availability of carers influenced the decision. Apart from the important need factors of elders, families’ views about alternatives to nursing homes were significantly influenced by their preferences. This study has important implications for long‐term care in Taiwan. It is hoped that this will be needs‐led, both by elderly people and their families.
Social Inequality under a New Social Contract: Long‐term Care in Japan
Authors: Izuhara Misa
Published: December 2004

The 1990s saw the beginning of new developments in the social policy agenda of Japan. A combination of further cuts in social expenditure and increases in financial resources through various means has become inevitable in response to the increasing cost burden of an ageing society, the prolonged recession and changes in the Japanese family. In this context, “kaigo hoken” (long‐term care insurance) was introduced in 2000 to increase revenue and fill the gap vacated by the family. The scheme introduced a different concept to the public: that long‐term care was no longer “expected’’ from the family or “allocated” by the state, but has become part of a “social contract” based upon a system of mandatory contributions, uniform entitlements and consumer choice. This paper first explores the role of the new scheme in creating social inequalities among individuals (and families). A panel survey is used to highlight different patterns of care provision and the varying degree of financial pressure among different income groups. Second, based on qualitative research, the paper examines how the new scheme has transformed the relationship between older people and their families who have played a central role in this arena. The scheme has consequently divided “traditional” families and their liberal counterparts, as a result of care work being “commodified”. It is apparent that this scheme has not only responded to fill the existing care gap but may also help accelerate the changes that have been taking place for the last two decades.
New Economy and New Social Policy in East and Southeast Asian Compact, Mature Economies: The Case of Hong Kong
Authors: Chow Nelson Wing‐sun
Published: December 2004

In the 1970s, as the now compact, mature economies in East and Southeast Asia were industrializing, their governments had claimed that they saw no need for the kind of welfare programmes developed in Western “welfare states”. Notwithstanding this claim, a study of social welfare development in these economies in the last three decades, particularly when Hong Kong is taken as an example, shows that they have gone for universal social welfare, largely as a result of the growing prosperity and the rising expectations of the people. This trend has, however, been reversed since the start of the Asian financial crisis in the latter part of 1997, with the resultant slowing down of the economy, rising unemployment and surging fiscal deficits. Governments of the compact, mature economies in East and Southeast Asia found that they must rethink their social commitments and in order to return to balanced budgets, the former selective approach is now adopted by concentrating social welfare resources on the most needy people. While it is not in dispute that there is a close and positive relationship between industrialization and social welfare, the case of the compact, mature economies in East and Southeast Asia shows that as they are more vulnerable to world economic vicissitudes, the relationship may not be as steady as it has been in the Western industrial states.
Interpreting and Reinterpreting Agri‐Environmental Policy: Communication, Trust and Knowledge in the Implementation Process
Authors: Juntti Meri , Potter Clive
Published: December 2004

The role and importance of street‐level bureaucrats in policy implementation is now widely recognised. So far as the EU's agri‐environmental policy is concerned, however, a focus on the attitudes and behaviour of programme recipients (farmers and other land managers) has tended to obscure the role of street‐level bureaucrats responsible for extending and advising on schemes and the impact of their interpretive frameworks and communication practices on policy outcomes. This paper draws on interviews with extensionists and advisers in England and Finland in order to explore the different interpretations, which these actors bring to the implementation of agrienvironmental policy and to reflect on the implications of this for the way environmental advice is currently being offered to farmers within the agri‐environmental network.
Symbolic Power and Organizational Culture
Authors: Hallett Tim
Published: December 2004

With the recent wave of corporate scandals, organizational culture has regained relevance in politics and the media. However, to acquire enduring utility, the concept needs an overhaul to overcome the weaknesses of earlier approaches. As such, this paper reconceptualizes organizational culture as a negotiated order (Strauss 1978) that emerges through interactions between participants, an order influenced by those with the symbolic power to define the situation. I stress the complementary contributions of theorists of practice (Bourdieu and Swidler) and theorists of interaction (Goffman and Strauss), building upward from practice into interaction, symbolic power, and the negotiated order. Using data from initial reports on the fall of Arthur Andersen and Co., I compare this symbolic power approach to other approaches (culture as subjective beliefs and values or as context/public meaning). The symbolic power model has five virtues: an empirically observable object of study; the capacity to explain conflict and integration; the ability to explain stability and change; causal efficacy; and links between the micro-, meso-, and macrolevels of analysis. Though this paper focuses on organizational culture, the symbolic power model provides theoretical leverage for understanding many situated contexts.
The Natural Realm of Social Law
Authors: Donabedian Bairj
Published: December 2004

This paper proposes criteria for distinguishing those types of social forms that are susceptible to lawlike explanation from those that are susceptible to interpretive accounts. The main criterion concerns the rankability of choice alternatives. The choice process is modeled as having two subprocesses. The first subprocess is a rational one in which unacceptable decision alternatives are eliminated, reducing the universe of alternatives to the set of interchangeably acceptable options, termed the admissible set. In the second subprocess, an arbitrary choice is made from the admissible set. In rational-choice settings, the admissible set consists of just one element, the optimum. However, this is clearly not the only possibility, as the example of language, with its plurality of interchangeable phonemic options, bears witness. The fundamental concept: At one extreme—the extreme of language—the admissible set is large and the arbitrary-choice subprocess dominates the rational-choice subprocess. At the other extreme—the extreme of rational-choice theory—the admissible set consists of a single element and the rational-choice subprocess dominates the arbitrary-choice subprocess. Social law has its proper home in those territories of human activity where the admissible set is small; social interpretation has its proper home in those regions where the admissible set is large.
Pseudoclefts
Authors: Bošković Željko
Published: December 2004

This paper focuses on the syntax of specificational pseudoclefts. To account for the fact that in spite of the apparent lack of c‐command, elements in the wh‐clause of specificational pseudoclefts are able to enter into connectivity relations that require c‐command with the elements in the focus phrase, including the antecedent‐trace relation in certain well‐defined cases, I argue that the focused phrase moves in LF into the who‐clause. The movement is shown to have broad theoretical consequences and to provide a uniform account of a number of othewise puzzling properties of pseudoclefts, including several differences between regular specificational, inverted specificational, and predicational pseudoclefts.
Weakly Nonlinear Stability Analysis of Frontal Polymerization
Authors: Gross L. K. , Volpert V. A.
Published: December 2004

A description of frontal polymerization is given via a free boundary model with nonlinear kinetic and kinematic conditions at the free boundary. We perform a weakly nonlinear analysis for the development of pulsating instabilities on the cylinder, building on the linear stability analysis of [1]. We take as a bifurcation parameter an experimentally measurable combination of material and kinetic parameters. The asymptotic analysis leads to the derivation of an ordinary differential equation of Landau–Stuart type for the slowly varying amplitude of a linearly unstable mode. We classify nonlinear dynamics of the polymerization front by doing a parameter sensitivity study of the amplitude equation.
Weakly Nonhydrostatic Effects in Compositionally‐Driven Gravity Flows
Authors: Antar N. , Moodie T. B.
Published: December 2004

In the study of compositionally‐driven gravity currents it is customary to adopt the hydrostatic assumption for the pressure field which, in turn, leads to a depth‐independent horizontal velocity field and significant simpilifications to the governing equations. The hydrostatic assumption is reasonable in, say, the case of a two‐layer flow when the depth variations of the lower layer are small when considered as a function of space and time. However, for larger deflections of the interface (such as those caused by bottom topography) the flow will deviate in its behavior from the low aspect ratio, slowly varying purely hydrostatic flow because of the presence of vertical accelerations. In this paper we present an approach to capture the contribution of interface curvature to nonhydrostatic effects in fully time‐dependent flows in two‐fluid systems. Our approach involves expanding the relevant dependent variables in the form of an asymptotic expansion f=f(0)+δ2f(1)+o(δ2), where 0 < δ≪ 1 is the aspect ratio of the flow, and obtaining the first‐order correction to hydrostatic theory. Numerical results and comparisions with the purely hydrostatic theory are included.
On the Number of Cycles in Randomly Selected Permutations
Authors: Laghate Kavita , Deshpande M.N.
Published: December 2004

In this article we derive the distribution, mean and variance of the number of cycles in a randomly selected permutation of the first n integers.
Intuition in Using Nominal Variables for Prediction
Authors: Suich Ron , Turek Richard
Published: December 2004

The notion of independence between two nominal variables is typically introduced through the use of chi‐square analysis of contingency tables, while the topic of prediction of one nominal variable from a second nominal variable using optimal prediction to the mode is often omitted. Through the use of a questionnaire, this article indicates that there is considerable confusion among students on the difference between the concepts of independence and prediction, and remedies are suggested.
A Hierarchical Model for Space–Time Surveillance Data on Meningococcal Disease Incidence
Authors: Knorr-Held Leonhard , Richardson Sylvia
Published: December 2004

We describe a model-based approach to analyse space–time surveillance data on meningococcal disease. Such data typically comprise a number of time series of disease counts, each representing a specific geographical area. We propose a hierarchical formulation, where latent parameters capture temporal, seasonal and spatial trends in disease incidence. We then add—for each area—a hidden Markov model to describe potential additional (autoregressive) effects of the number of cases at the previous time point. Different specifications for the functional form of this autoregressive term are compared which involve the number of cases in the same or in neighbouring areas. The two states of the Markov chain can be interpreted as representing an ‘endemic’ and a ‘hyperendemic’ state. The methodology is applied to a data set of monthly counts of the incidence of meningococcal disease in the 94 départements of France from 1985 to 1997. Inference is carried out by using Markov chain Monte Carlo simulation techniques in a fully Bayesian framework. We emphasize that a central feature of our model is the possibility of calculating—for each region and each time point—the posterior probability of being in a hyperendemic state, adjusted for global spatial and temporal trends, which we believe is of particular public health interest.
Assessment of Athens's Metro Passenger Behaviour Via a Multiranked Probit Model
Authors: Linardakis Michalis , Dellaportas Petros
Published: December 2004

We deal with real data from a stated preference experiment which was designed to explain and predict passengers’ behaviour towards three main means of transportation in the city of Athens. The resulting model formulations give rise to the so-called multiranked probit model which emerges from a series of ranking responses in a set of hypothetical scenarios, i.e. we enhance the multinomial probit model with the embodiment of a utility threshold parameter which deals realistically with ranking responses, intransitivity of indifference between alternatives or ties. Moreover, we ensure identifiable parameters for the covariance matrix of the underlying utility vectors, we include a hierarchical step that models the unit-specific utility thresholds as exchangeably distributed and, finally, we permit the use of heavy-tailed distributions for the stochastic error term. Our proposed methodology is Bayesian and the implementation tool adopted is Markov chain Monte Carlo sampling. The posterior output consists of practical information such as travel characteristics (e.g. walking times and waiting times), expressed either in drachmas per hour or in minutes of in-vehicle time, and 95% credible intervals of the probability of choosing a particular mode of transportation. These are key factors in determining whether a policy has positive or negative net benefits.
Reconstructing the Incidence of Human Immunodeficiency Virus (HIV) in Hong Kong by Using Data From HIV Positive Tests and Diagnoses of Acquired Immune Deficiency Syndrome
Authors: Chau P. H. , Yip Paul S. F. , Cui Jisheng S.
Published: December 2004

The human immunodeficiency virus–acquired immune deficiency syndrome (HIV–AIDS) epidemic in Hong Kong has been under surveillance in the form of voluntary reporting since 1984. However, there has been little discussion or research on the reconstruction of the HIV incidence curve. This paper is the first to use a modified back-projection method to estimate the incidence of HIV in Hong Kong on the basis of the number of positive HIV tests only. The model proposed has several advantages over the original back-projection method based on AIDS data only. First, not all HIV-infected individuals will develop AIDS by the time of analysis, but some of them may undertake an HIV test; therefore, the HIV data set contains more information than the AIDS data set. Second, the HIV diagnosis curve usually has a smoother pattern than the AIDS diagnosis curve, as it is not affected by redefinition of AIDS. Third, the time to positive HIV diagnosis is unlikely to be affected by treatment effects, as it is unlikely that an individual receives medication before the diagnosis of HIV. Fourth, the induction period from HIV infection to the first HIV positive test is usually shorter than the incubation period which is from HIV infection to diagnosis of AIDS. With a shorter induction period, more information becomes available for estimating the HIV incidence curve. Finally, this method requires the number of positive HIV diagnoses only, which is readily available from HIV–AIDS surveillance systems in many countries. It is estimated that, in Hong Kong, the cumulative number of HIV infections during the period 1979–2000 is about 2600, whereas an estimate based only on AIDS data seems to give an underestimate.
Modelling Accelerated Life Test Data by Using a Bayesian Approach
Authors: Sinha Debajyoti , Patra Kauhsik , Dey Dipak K.
Published: December 2004

Because of the high reliability of many modern products, accelerated life tests are becoming widely used to obtain timely information about their time-to-failure distributions. We propose a general class of accelerated life testing models which are motivated by the actual failure process of units from a limited failure population with a positive probability of not failing during the technological lifetime. We demonstrate a Bayesian approach to this problem, using a new class of models with non-monotone hazard rates, the hazard model with potential scope for use far beyond accelerated life testing. Our methods are illustrated with the modelling and analysis of a data set on lifetimes of printed circuit boards under humidity accelerated life testing.
Governmentality, subject‐building, and the discourses and practices of devolution in the UK
Authors: Raco Mike
Published: December 2004

This paper uses a Foucauldian governmentality framework to analyse and interrogate the discourses and strategies adopted by the state and sections of the business community in their attempts to shape and influence emerging agendas of governance in post‐devolution Scotland. Much of the work on governmentality has examined the ways in which governments have developed particular techniques, rationales and mechanisms to enable the functioning of governance programmes. This paper expands upon such analyses by also looking at the ways in which particular interests may use similar procedures, discourses and practices to promote their own agendas and develop new forms of resistance, contestation and challenge to emerging policy frameworks. Using the example of business interest mobilization in post‐devolution Scotland, it is argued that governments may seek to mobilize defined forms of expertise and knowledge, linking them to wider political debates. This, however, creates new opportunities for interests to shape and contest the discourses and practices of government. The governmentalization of politics can, therefore, be seen as more of a dialectical process of definition and contestation than is often apparent in existing Foucault‐inspired writing.
Molecular bases of the antigens of the Lutheran blood group system
Authors: Crew Vanja Karamatic , Green Carole , Daniels Geoff
Published: December 2004

BACKGROUND: Lutheran is a complex blood group system consisting of 18 identified antigens. There are four pairs of allelic antigens, whereas others are independently expressed antigens of a high frequency. Lutheran antigens are carried by the Lutheran glycoproteins, which are a product of a single gene LU.

STUDY DESIGN AND METHODS: Genomic DNA from 21 individuals of 12 Lutheran phenotypes was used for PCR amplification of selected LU exons that were directly sequenced and compared to control DNA of a common Lutheran phenotype.

RESULTS: Lutheran phenotypes were mostly caused by single‐nucleotide polymorphisms within LU, resulting in single amino acid changes. The following mutations were observed: in LU:−4, G524A, Arg175Gln; in LU:−5, G326A, Arg109His; in LU:−6,9, C824T, Ser275Phe; in LU:−8,14, T611A, Met204Lys; in LU:−13, three point mutations (C1340T, Ser447Leu, C1671T silent mutation for Ser557 and A1742T, Gln581Leu); in LU:−16, C679T, Arg227Cys; in LU:−17, G340A, Glu114Lys; and in LU:−20, C905T, Thr302Met. Two LU:−12 samples had differing results: one individual had a deletion 99GCGCTT, Arg34 and Leu35, whereas the second LU:−12 sample had a point mutation G419A, Arg140Gln.

CONCLUSION: The results revealed the genetic background of 11 Lutheran antigens and suggested their placement on the Lutheran glycoprotein.
Leukoreduction in the setting of open heart surgery: a prospective cohort‐controlled study
Authors: Fung Mark K. , Rao Nalini , Rice Janet , Ridenour Marilyn , Mook William , Triulzi Darrell J.
Published: December 2004

BACKGROUND:  Proven clinical benefits of leukoreduced blood components include reduced febrile nonhemolytic transfusion reactions, alloimmunization against HLA antigens, and CMV transmission. Immunomodulatory effects of leukoreduction have also been postulated to play a significant role in the clinical outcome of open heart surgery.

STUDY DESIGN AND METHODS:  A prospective case control study was implemented in which all patients admitted over a 1‐year period for open heart surgery at a single hospital were given leukoreduced blood products. Clinical outcomes were prospectively measured and compared to a historical cohort of patients from the previous year when leukoreduced blood products were not routinely used.

RESULTS:  A significant improvement in the mean postoperative length of stay was seen in the study group (N = 645) versus control group (N = 501; 10.1 vs. 9.5 days; p = 0.005). No significant changes were seen in the rate of mediastinitis, operative mortality, or stay in the intensive care unit. There was no difference in the postoperative length of stay among study patients who did not receive transfusion (N = 308) versus control patients who did not receive transfusion (N = 296; 6.2 vs. 6.4 days; p = 0.104).

CONCLUSIONS:  The use of leukoreduced blood was associated with a decrease in the postoperative length of stay in the setting of open heart surgery. The mechanisms through which these changes in clinical outcomes are generated remain unknown.
Early formation of K‐feldspar in shallow‐marine sediments at near‐surface temperatures (southern Israel): evidence from K‐Ar dating
Authors: Sandler Amir , Harlavan Yehudit , Steinitz Gideon
Published: December 2004

Authigenic K‐feldspar was investigated in two Albian to Turonian sections in Israel using K‐Ar and Ar‐Ar dating, X‐ray diffraction, scanning electron microscopy and chemical analysis. Both sections comprise a similar succession of shallow‐marine limestones, dolomites and marls, with some sandstone and shale beds of continental origin. The HCl‐insoluble residue fraction of the studied samples consists of clays, quartz, feldspars, goethite and trace amounts of heavy minerals. Most of the insoluble residues have a relatively high K‐feldspar content that has an adularia habit and is concentrated in the 4–7 µm size fraction. The authigenic origin of the K‐feldspar in the fine silt fraction is indicated by its high content relative to quartz, the uniform and idiomorphic shape of the crystals and its limited size range. Of the fine silt (4–7 or 4–10 µm) separates, 40% have ages that are similar to stratigraphic ages within the analytical and biostratigraphic errors. Ar‐Ar dating of a fine silt fraction with 94% K‐feldspar (4–10 µm, sample GYP 7) yields a plateau age identical to the total gas age and similar to the stratigraphic age. These results indicate that the K‐Ar age is not a mixture between detrital and late diagenetic K‐feldspar ages, but is rather an age of formation within a few million years after deposition. It is suggested that the early formation of the K‐feldspar was associated with dolomitization and was induced by residual brines as part of a reflux process.
Membrane topology and sequence requirements for oil body targeting of oleosin
Authors: Abell Ben M. , Hahn Margaret , Holbrook Larry A. , Moloney Maurice M.
Published: December 2004

Oleosin protein is targeted to oil bodies via the endoplasmic reticulum (ER) and consists of a lipid‐submerged hydrophobic (H) domain that is flanked by cytosolic hydrophilic domains. We investigated the relationship between oleosin ER topology and its subsequent ability to target to oil bodies. Oleosin variants were created to yield differing ER membrane topologies and tagged with a reporter enzyme. Localisation was assessed by fractionation after transient expression in embryonic cells. Membrane‐straddled topologies with N‐terminal sequence in the ER lumen and C‐terminal sequence in the cytosol were unable to target to oil bodies efficiently. Similarly, a translocated topology with only ER membrane and lumenal sequence was unable to target to oil bodies efficiently. Both topology variants accumulated proportionately higher in ER microsomal fractions, demonstrating a block in transferring from ER to oil bodies. The residual oil body accumulation for the inverted topology was shown to be because of partial adoption of native ER membrane topology, using a reporter variant, which becomes inactivated by ER‐mediated glycosylation. In addition, the importance of H domain sequence for oil body targeting was assessed using variants that maintain native ER topology. The central proline knot motif (PKM) has previously been shown to be critical for oil body targeting, but here the arms of the H domain flanking this motif were shown to be interchangeable with only a moderate reduction in oil body targeting. We conclude that oil body targeting of oleosin depends on a specific ER membrane topology but does not require a specific sequence in the H domain flanking arms.
Membrane‐bound fatty acid desaturases are inserted co‐translationally into the ER and contain different ER retrieval motifs at their carboxy termini
Authors: McCartney Andrew W. , Dyer John M. , Dhanoa Preetinder K. , Kim Peter K. , Andrews David W. , McNew James A. , Mullen Robert T.
Published: December 2004

Fatty acid desaturases (FADs) play a prominent role in plant lipid metabolism and are located in various subcellular compartments, including the endoplasmic reticulum (ER). To investigate the biogenesis of ER‐localized membrane‐bound FADs, we characterized the mechanisms responsible for insertion of Arabidopsis FAD2 and Brassica FAD3 into ER membranes and determined the molecular signals that maintain their ER residency. Using in vitro transcription/translation reactions with ER‐derived microsomes, we show that both FAD2 and FAD3 are efficiently integrated into membranes by a co‐translational, translocon‐mediated pathway. We also demonstrate that while the C‐terminus of FAD3 (‐KSKIN) contains a functional prototypic dilysine ER retrieval motif, FAD2 contains a novel C‐terminal aromatic amino acid‐containing sequence (‐YNNKL) that is both necessary and sufficient for maintaining localization in the ER. Co‐expression of a membrane‐bound reporter protein containing the FAD2 C‐terminus with a dominant‐negative mutant of ADP‐ribosylation factor (Arf)1 abolished transient localization of the reporter protein in the Golgi, indicating that the FAD2 peptide signal acts as an ER retrieval motif. Mutational analysis of the FAD2 ER retrieval signal revealed a sequence‐specific motif consisting of Φ‐X‐X‐K/R/D/E‐Φ‐COOH, where ‐Φ‐ are large hydrophobic amino acid residues. Interestingly, this aromatic motif was present in a variety of other known and putative ER membrane proteins, including cytochrome P450 and the peroxisomal biogenesis factor Pex10p. Taken together, these data describe the insertion and retrieval mechanisms of FADs and define a new ER localization signal in plants that is responsible for the retrieval of escaped membrane proteins back to the ER.
Heterosis in the freezing tolerance of crosses between two Arabidopsis thaliana accessions (Columbia‐0 and C24) that show differences in non‐acclimated and acclimated freezing tolerance
Authors: Rohde Peter , Hincha Dirk K. , Heyer Arnd G.
Published: December 2004

Heterosis is broadly defined as the increased vigour of hybrids in comparison to their parents. In the model plant Arabidopsis thaliana, a significant heterosis effect on leaf‐freezing tolerance was observed in the F1 generation of a cross between the accessions Columbia‐0 (Col) and C24. Parental Col plants were significantly more freezing‐tolerant than C24 plants in both the acclimated and non‐acclimated (NA) states. Mid‐parent heterosis was observed in the F1 plants, both in the basic tolerance of non‐adapted plants and in freezing tolerance after cold acclimation. Best‐parent heterosis, on the other hand, was only found after cold acclimation. The heterosis effect was reduced in the F2 populations such that only mid‐parent heterosis was evident. The leaf content of soluble sugars (fructose (Fru), glucose (Glc), sucrose (Suc) and raffinose (Raf)) increased dramatically in the F1 plants after cold acclimation as compared to the parental lines. The content of proline (Pro), however, was only moderately increased in the F1 plants under the same conditions. Correlation analyses showed that only Raf content was consistently related to leaf‐freezing tolerance in both the acclimated and NA states. A quantification of mRNA levels in leaves of parental and F1 lines using quantitative real‐time RT‐PCR showed no clear indication for an involvement of the investigated genes (CBF (C‐repeat binding factor)1, CBF2, (cold‐regulated protein (COR) 6.6, COR15a, COR15b, COR47 and COR78) in the heterosis effect.
The nuclear factor HCF145 affects chloroplast psaA‐psaB‐rps14 transcript abundance in Arabidopsis thaliana
Authors: Lezhneva Lina , Meurer Jörg
Published: December 2004

The high chlorophyll fluorescence (hcf)145 mutant of Arabidopsis thaliana is specifically affected in photosystem (PS)I function as judged from spectroscopic analysis of PSII and PSI activity. The defect is because of a severe deficiency of PSI core subunits, whereas levels of the four outer antenna subunits of PSI were less reduced in hcf145. Pulse labelling of chloroplast proteins indicated that synthesis of the two largest PSI reaction‐centre polypeptides, Psa (photosystem I subunit) A and PsaB, is significantly affected by the mutation. A comparison of stationary transcript levels with rates of transcription demonstrates that hcf145 induces a decreased stability and, probably, transcription of the tricistronic psaA‐psaB‐rps (small‐subunit ribosomal protein)14 mRNA, which is generated by the plastid‐encoded RNA polymerase. Translation inhibition experiments excluded translational defects as primary cause of impaired mRNA stability. Larger primary transcripts, which also contain sequences of the ycf3 (hypothetical chloroplast reading frame) gene located upstream of the psaA‐psaB‐rps14 operon and generated by the action of the nuclear‐encoded RNA polymerase, are not targeted by the mutation. Real‐time reverse transcription (RT)‐PCR analysis has successfully been applied to quantify defined intervals of the tricistronic transcript and it was established that the psaA region is less stable than the rps14 region in hcf145. The hcf145 gene has been mapped on the upper part of chromosome 5.
A modified viral satellite DNA that suppresses gene expression in plants
Authors: Tao Xiaorong , Zhou Xueping
Published: December 2004

DNAβ is a type of single‐stranded (ss) circular satellite DNA found in association with monopartite‐genome begomoviruses, such as Tomato yellow leaf curl China virus isolate Y10 (TYLCCNV‐Y10). Y10 DNAβ is required for symptom expression in plants but depends on TYLCCNV‐Y10 genomic DNA (DNA‐A) for replication and encapsidation. When we converted DNAβ into a gene‐silencing vector (modified DNAβ (DNAmβ)) by replacing its C1 open‐reading frame (ORF) with a multiple cloning site (MCS), it was replicated but no longer induced symptoms in association with TYLCCNV‐Y10 DNA‐A, so allowing the effects of gene inserts to be recognized easily. Insertion into DNAmβ of sequences from any of the three host genes (proliferating cell nuclear antigen (PCNA), phytoene desaturase (PDS), and sulfur (Su)), or from a transgene (green fluorescent protein (GFP)), resulted in silencing of the cognate gene in Nicotiana benthamiana. The silencing persisted for more than a month and was associated with decreased levels of mRNA of the gene targeted. Although DNAmβ probably does not enter meristematic tissue, the PCNA gene could be silenced there. DNAmβ was an effective silencing vector in tested N. glutinosa, N. tabacum Samsun (NN or nn), and Lycopersicon esculentum plants, and was able to silence two genes simultaneously. This satellite DNA vector‐based form of virus‐induced gene silencing (VIGS) promises to be applicable to other begomovirus/DNAβ systems, which are recently reported to occur in several dicotyledonous crop species, thereby providing a powerful approach to gene discovery and the analysis of gene function in these crops.
Chromatin techniques for plant cells
Authors: Bowler Chris , Benvenuto Giovanna , Laflamme Pierre , Molino Diana , Probst Aline V. , Tariq Muhammad , Paszkowski Jerzy
Published: December 2004

A large number of recent studies have demonstrated that many important aspects of plant development are regulated by heritable changes in gene expression that do not involve changes in DNA sequence. Rather, these regulatory mechanisms involve modifications of chromatin structure that affect the accessibility of target genes to regulatory factors that can control their expression. The central component of chromatin is the nucleosome, containing the highly conserved histone proteins that are known to be subject to a wide range of post‐translational modifications, which act as recognition codes for the binding of chromatin‐associated factors. In addition to these histone modifications, DNA methylation can also have a dramatic influence on gene expression. To accommodate the burgeoning interest of the plant science community in the epigenetic control of plant development, a series of methods used routinely in our laboratories have been compiled that can facilitate the characterization of putative chromatin‐binding factors at the biochemical, molecular and cellular levels.
AtPTR1, a plasma membrane peptide transporter expressed during seed germination and in vascular tissue of Arabidopsis
Authors: Dietrich Daniela , Hammes Ulrich , Thor Kathrin , Suter‐Grotemeyer Marianne , Flückiger Ricardo , Slusarenko Alan J. , Ward John M. , Rentsch Doris
Published: December 2004

For the efficient translocation of organic nitrogen, small peptides of two to three amino acids are posited as an important alternative to amino acids. A new transporter mediating the uptake of di‐ and tripeptides was isolated from Arabidopsis thaliana by heterologous complementation of a peptide transport‐deficient Saccharomyces cerevisiae mutant. AtPTR1 mediated growth of S. cerevisiae cells on different di‐ and tripeptides and caused sensitivity to the phytotoxin phaseolotoxin. The spectrum of substrates recognized by AtPTR1 was determined in Xenopus laevis oocytes injected with AtPTR1 cRNA under voltage clamp conditions. AtPTR1 not only recognized a broad spectrum of di‐ and tripeptides, but also substrates lacking a peptide bond. However, amino acids, ω‐amino fatty acids or peptides with more than three amino acid residues did not interact with AtPTR1. At pH 5.5 AtPTR1 had an apparent lower affinity (K0.5 = 416 μm) for Ala‐Asp compared with Ala‐Ala (K0.5 = 54 μm) and Ala‐Lys (K0.5 = 112 μm). Transient expression of AtPTR1/GFP fusion proteins in tobacco protoplasts showed that AtPTR1 is localized at the plasma membrane. In addition, transgenic plants expressing the β‐glucuronidase (uidA) gene under control of the AtPTR1 promoter demonstrated expression in the vascular tissue throughout the plant, indicative of a role in long‐distance transport of di‐ and tripeptides.