bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection for resistance to acetamiprid and various other insecticides in the diamondback moth, Plutella xylostella (L.) (Lep., Plutellidae)
Authors: Ninsin K. D.
Published: July 2004

Abstract:  A diamondback moth (DBM) colony (KOBII) originally collected from cabbage fields of Iwaoka‐cho in Kobe City, Japan, where acetamiprid is the primary insecticide for DBM control was selected for studies on resistance to acetamiprid, phenthoate, esfenvalerate and cartap, using the leaf‐dipping method. Resistance to acetamiprid was slow to develop in KOBII compared with the other insecticides. Three selection experiments each with phenthoate and esfenvalerate yielded a resistance ratio (RR) of 140 and 222, respectively, in the selected strains compared with a part of KOBII that was not exposed to any insecticide (KOBII‐NS). Three selection experiments with cartap also gave an RR of 15. However, six selection experiments with acetamiprid yielded an RR of just 9.5 in the selected strain. When cross‐resistance to acetamiprid was evaluated, the cartap‐resistant strain showed a moderate level of cross‐resistance to acetamiprid. In the case of the phenthoate‐resistant strain, a very low cross‐resistance to acetamiprid was observed. There was however no discernible cross‐resistance to acetamiprid in the esfenvalerate‐resistant strain.
Age‐specific mating and reproductive senescence in the seven‐spotted ladybird, Coccinella septempunctata
Authors: Srivastava S. , Omkar
Published: July 2004

Abstract:  Adults of the seven‐spotted ladybird, Coccinella septempunctata Linnaeus (Col., Coccinellidae) were paired for mating from very young to old age (1–50 days) to record the willingness to mate, attainment of sexual maturity and onset of reproductive senescence in both the sexes. Mating commenced after 4 and 2 days of emergence of male and female, respectively, and 100% mating was achieved at the young age in both cases (10 days). Willingness to mate decreased with increase in the age from 40 to 50 days of both the sexes. Ladybird exhibited protandry. Mating duration, fecundity and per cent viability of eggs of middle‐aged males (20–30 days old) and females (20 days old) were the highest. Mating duration and per cent viability of eggs were male age dependent, whereas pre‐oviposition and oviposition periods were mating stimulus dependent. Oviposition period and fecundity were female age‐dependent responses. Fecundity was highest when 20‐day‐old female and 30‐day‐old male were paired. Onset of reproductive senescence started at the age of 30 days in males and 20 days in females. The present study confirms the effect of ageing on male and female C. septempunctata and supports the Hansen and Price [J. Evol. Biol. (1995) vol. 8, pp. 759–778] model that females mating with young and middle‐aged males yield optimal quality progeny.
Diel periodicity and influence of age and mating on female sex pheromone titre in Estigmene acrea (Lep., Arctiidae)
Authors: Del Mazo‐Cancino A. , Malo E. A. , Cruz‐López L. , Rojas J. C.
Published: July 2004

Abstract:  Calling behaviour, diel periodicity, and effect of age and mating on female sex pheromone titre in Estigmene acrea (Drury) were studied under laboratory conditions. Forty‐five per cent of females started calling during the first scotophase, but the highest number of calling females was observed during the second, third and fourth scotophases. Calling behaviour occurred from the third hour after dark until just before the end of the scotophase. However, females exhibited a bimodal pattern of calling with the first peak occurring between 4 and 6 h and a second peak at 10 h after the onset of scotophase. The mean onset of calling time differed significantly with age. Older females showed a tendency to call longer, but there was no significant difference. The amount of (Z,Z)‐3,6‐cis‐9, 10‐epoxyheneicosadiene in females was quantified from the first scotophase following emergence, until the fifth scotophase. Glands of 0‐day‐old females presented a higher content of pheromone compared with that found in glands of 1‐, 2‐, 3‐ and 4‐day‐old females. Pheromone titre was determined at 2‐h intervals throughout the third scotophase and photophase. (Z,Z)‐3,6‐cis‐9,10‐epoxyheneicosadiene was found in the gland during the scotophase as well as the photophase. However, there was no consistent pattern of pheromone production throughout the scotophase or photophase. Mated females of E. acrea produced significantly less pheromone than virgin females.
Uncommon Ground: The ‘Poverty of History’ in Common Property Discourse
Authors: Johnson Craig
Published: July 2004

It would not be a great exaggeration to say that scholars of environmental conservation and conflict have re‐discovered the institutional foundations of social and economic life. At the heart of this ‘renaissance’ is the belief that property and property relations have a strong bearing on how people use, manage and abuse natural resource systems, and that institutional arrangements based on the creation and management of common property can have positive impacts on resource use and conservation. Two bodies of thought compete for a voice in this literature. One, which aims to resolve Hardin's tragedy of the commons, is primarily concerned with the problem of encouraging collective action to conserve resources that are both depletable and unregulated. A second, influenced by notions of moral economy and entitlement, deals with the problem of creating and sustaining resource access for poor and vulnerable groups in society. This article argues that the literature on common property has become divided between a body of scholarship that uses deductive models of individual decision‐making and rational choice to explain the ways in which different types of property rights arrangements emerge and change over time, and one whose questions, aims and methods are more modest, and historically‐specific. It then aims to understand this evolution by situating the mainstream common property discourse in the wider intellectual trend of positivism, methodological individualism and formal modelling that has come to dominate social science in the United States. In so doing, it attempts to unravel the political and ideological foundations of what has come to be a dominant mode of understanding environmental problems, and solutions to these problems.
Border Practices, Boundaries, and the Control of Resource Access: A Case from China, Thailand and Burma
Authors: Sturgeon Janet C.
Published: July 2004

This article traces border practices along boundaries that China and Thailand share with Burma. It portrays a spectrum of small border polities, from principalities on the fringes of Southeast Asian kingdoms, through Nationalist troops in Burma following their defeat in China, to ‘drug lords’ and ‘rebel armies’. The focus here is on Akha village heads who have worked their connections in multiple directions, including into Burma, to position themselves as patrons controlling local resource access. With state appointment as border guardians, village heads become chiefs of new kinds of small border entities, protecting the border for the homeland while enabling certain illicit information, people, and goods to cross. In regions with a history of complex patronage relations, state efforts to control peripheral people, resources, and territories have in fact produced small border chiefs, with practices similar to those of frontier princes in the past.
Can the World Bank Enforce its Own Conditions?
Authors: Thomas M. A.
Published: July 2004

In the 1980s, the World Bank stepped up policy‐based lending, making loans conditional on government policy and institutional reforms in the borrower country. In 2002, policy‐based lending (or adjustment loans) accounted for 64 per cent of total commitments. Some critics have argued that conditionality has failed because borrowers do not comply with conditions, and that borrowers do not comply because donors do not enforce the conditions, due to their own institutional incentives to lend. Accordingly, they argue that conditionality should be abandoned in favour of selectivity, a strategy in which donors would lend to governments that already have good policies and institutions in place. This article reviews the evidence that has been offered for this ‘enforcement critique’ and finds that it is not sufficient to support the argument. Although the critique is often asserted, and although there is ample evidence of lending pressures, no studies have attempted to determine whether borrower non‐compliance is a serious problem, or whether Bank failures to enforce are the principal reason for the failure of borrowers to meet conditions; nor have any studies been carried out to show whether lending pressures are the main reason for the Bank's failure to enforce.
Constructing Poverty Trends in Uganda: A Multidisciplinary Perspective
Authors: McGee Rosemary
Published: July 2004

In late 1999, apparently contradictory pictures of what was happening to poverty in Uganda emerged from the Participatory Poverty Assessment (PPA) and the household survey. This article analyses certain conceptual and methodological characteristics of the PPA and the pictures of poverty trends arising from it, with a view to dispelling confusion and to better understanding the relationship between these and the pictures emerging from survey data. It argues that the apparently contradictory visions, when explored carefully, are found to be compatible, and concludes that deeper and less oppositional understandings of the purpose of PPAs vis‐à‐vis surveys for poverty assessment are an important and timely contribution to current research and knowledge about poverty.
Towards a Political Economy of Roads: Experiences from Peru
Authors: Wilson Fiona
Published: July 2004

This article looks at why states build roads, and in what circumstances roads become a priority for rural people. To distinguish between situations of spatial autonomy and isolation, a concept of territorializing regime is elaborated. This is employed to discuss road‐building undertaken by the state in the Peruvian Andes and to examine practices of mobility in Andean indigenous/rural society. While a location ‘off the beaten track’ could be a source of autonomy in the past, the author outlines reasons why people in post‐conflict, neo‐liberal Peru now dedicate much time and energy to road‐building, even though this may potentially lead to loss of land, community control and greater impoverishment.
Economic Globalization and Institutions of Global Governance: Comments and Debate (I)
Authors: Emmerij Louis
Published: July 2004

Reading Keith Griffin is like listening to a Frenchman presenting his ideas in three parts and ten minutes. It is clear, brilliant, and a delight for the ear, but once it is over you scratch your head and wonder what exactly the meaning of it all was. In the recent article by Griffin published in this journal (Griffin, 2003), there were two instances where I scratched my head. The first instance was when he pleaded in favour of mobility of the factor labour, not only of labour in general, but of unskilled labour in particular in order to reduce global income inequalities. The second instance occurred when he argued in favour of a compulsory tax and transfer mechanism in replacement of the old‐style foreign aid that is ‘nearly obsolete’.
Threat as a Motivator of Political Activism: A Field Experiment
Authors: Miller Joanne M. , Krosnick Jon A.
Published: July 2004

The research reported here examined the effects of two potential motivators of political activism—policy change threat and policy change opportunity—in a field experiment. Different versions of a letter were sent by a political lobbying organization to potential contributors. One version highlighted threats of undesirable policy changes, another version highlighted opportunities for desirable policy changes, and the third version did neither. Policy change threat increased the number of financial contributions made to the interest group, but policy change opportunity did not. Policy change opportunity increased the number of signed postcards returned to be sent to President Clinton, but policy change threat did not. These findings highlight the impact of interest group recruitment strategies on citizen responsiveness and demonstrate the need to account for sources of motivation in order to more fully understand when, why, and how citizens choose to become politically active.
Does Moving Disrupt Campaign Activity?
Authors: Bowers Jake
Published: July 2004

Findings from cross‐sectional studies cannot tell us whether moving leads to changes in civic activity, because such studies do not observe the same individual's participation before and after moves. This paper treats both moving and participation as dynamic processes, analyzing data that cover 18 years within lives of two generations of Americans. The results suggest that our general understanding about who participates cannot account for the patterns evident in even the simplest of descriptions of this phenomenon. Moving is shown to disrupt moments of campaign activity. However, the specific patterns of this disruption across generations and types of acts lead to more questions about the mechanism by which moving interferes with the political activity of ordinary Americans.
Inside the Black Box of Negative Campaign Effects: Three Reasons Why Negative Campaigns Mobilize
Authors: Martin Paul S.
Published: July 2004

The debate over the effect of negative campaigns on vote turnout has not been settled. At present, studies demonstrating a mobilization effect seem to have the upper hand. However, neither side has offered a compelling theory of the causal mechanisms that connect negative campaigns and voter turnout. This paper identifies three mechanisms of voter motivation—republican duty, candidate threat, and perceived closeness of the election—and tests the influence of negative ads on each. The findings suggest that each works to plausibly translate exposure to negative advertisement into increased participation.
Survival of the Fittest: Rhetoric During the Course of an Election Campaign
Authors: Jerit Jennifer
Published: July 2004

Despite the tradition of studying campaign effects, we know little about the rhetorical strategies of candidates. This study speculates about the types of appeals that incumbents and challengers find most effective and that are, as a result, most likely to dominate an election campaign. Candidates have an incentive to use arguments that evoke emotions such as fear, anxiety, and anger. Emotional appeals allow candidates to emphasize consensual values, which makes it easier to mobilize their party's base while simultaneously attracting the support of the uncommitted. The use of emotional appeals is also consistent with the media's preference for drama and excitement in news reporting. Thus, emotional appeals will be more enduring than other types of appeals, and hence more likely to dominate the rhetorical landscape. A content analysis of newspaper coverage of the 1988 Canadian federal election campaign provides suggestive evidence in favor of this view.
Priming the Vote: Campaign Effects in a U.S. Senate Election
Authors: Druckman James N.
Published: July 2004

A growing body of evidence suggests that campaigns affect voters by priming the criteria on which voters base their decisions. Yet virtually all of this work uses simulated campaign rhetoric and/or relies on indirect measures of vote choice. This paper combines a content analysis of media campaign coverage with an Election Day exit poll to explore the impact of a real‐world campaign—the 2000 campaign for the U.S. Senate in Minnesota—on voters’ decisions. In this case, the campaign did in fact prime exposed and attentive voters to base their decisions on the issues and images emphasized in the campaign. Such campaign effects were reinforced by interpersonal discussions. The results constitute the first demonstration of priming effects in a U.S. election with voters at the polls.
Close Encounters With the Midwest: Forming Identity in a Bicultural Context
Authors: Smith Allison G. , Stewart Abigail J. , Winter David G.
Published: July 2004

This study uses semi‐structured interviews to examine how 16 people of Latvian heritage negotiated their cultural identities in high school (retrospectively) and at midlife (concurrently). Participants’ high school and midlife cultural identity patterns were coded as marginalized, separated, assimilated, alternating integrated, or blended integrated. Although eleven participants were found to have had marginalized, separated, or alternating integrated patterns in high school, all 16 had either assimilated or blended integrated patterns at midlife. Further, there is evidence that the contexts in which identity negotiation occurred—specifically, the rigidity of the participants’ Latvian and American contexts in high school and their relative openness at midlife—influenced these changes in pattern. The findings also underscore the importance of taking into account within‐group differences when studying how people negotiate their cultural identities.
Nurtured from Above and Growing from the Roots: Social Investment Funds and Decentralization in Zambia and Malawi
Authors: Van Donge Jankees
Published: July 2004

Social investment funds aim at the provision of social infrastructure through community involvement and participatory procedures. This paper focuses on two specific social investment funds, those in Zambia and Malawi. Both have a strong commitment to participation by the community, signified particularly in direct disbursement to those communities. They aim to work through the field units of government administration in a decentralized manner instead of creating parallel structures. The Zambian social fund has decentralized its procedures to a considerable degree, and it is a role model in this respect. The Malawian social fund is not such a powerful catalyst for organizational change, as it is confronted with much stronger residues of authoritarianism. Nevertheless, like the Zambian fund, it is an effective and cheap mechanism for delivery of social infrastructure. Both social investment funds are resisting merger, with comprehensive decentralization programmes aiming to bring the district administration under an elected local authority that Zambia and Malawi have both initiated. This paper argues that this resistance is rational. It pleads for an organic growth of decentralization instead of legislating it into existence. The experience of these social investment funds show that it is more fruitful to graft the decentralized procedures of social funds on to existing institutions than to embark on comprehensive decentralization programmes.
Social Exclusion and Participation in Community Development Projects: Evidence from Senegal
Authors: Dorsner Claire
Published: July 2004

This article seeks to provide a new insight into the debate about participation through a comprehensive analysis of the mechanisms at play behind community participation. The combined use of the concepts of social exclusion and of game theory is explored as a dynamic and innovative analytical tool to understand participatory processes in community development projects. The framework is tested against the analysis of participation in an NGO‐led community project in Senegal. Policy implications point to a need to unravel the complexity of participation to design more effective and sustainable community development projects.
Community Empowerment and Democracy in Zimbabwe: A Case Study from Binga District
Authors: Conyers Diana , Cumanzala Fanuel
Published: July 2004

The development of an “informed and alert electorate” is essential for the establishment of democratic governance in Africa and for the continent's future economic growth. This need is particularly evident in Zimbabwe, which is currently in the midst of an acute political and economic crisis. This paper tells the story of a small community‐based organization in a remote part of Zimbabwe, which helped to raise political awareness and consciousness among a dis‐advantaged rural population. Because of the threat that it posed to the Mugabe government, the organization was forced to close in October 2002. However, its experience has important lessons for the future development of Zimbabwe—and of Africa as a whole.
The Impact of Game Reserve Policy on the River BaSarwa/Bushmen of Botswana
Authors: Bolaane Maitseo
Published: July 2004

The aim of this paper is to present a background discussion on the impact of game reserve policy on Bugakhwe, “River BaSarwa” (Bushmen/San people) in Eastern Ngamiland. The issues of local community ownership and its relationship to perceptions of what constitutes a rural develop‐ment, and the problems of land rights, wildlife management and settlement, are important in the booming industry of the Okavango region. When the Moremi Game Reserve was created in 1963, the San of Khwaai were moved out and relocated in their present position, at the north gate of the Moremi Game Reserve. The question of access to traditional land and its resources has characterized the BaSarwa's response to the government's Community Based Natural Resource Management (CBNRM) initiative of 1995.
The Roots of Community Development in Colonial Office Policy and Practice in Africa
Authors: Smyth Rosaleen
Published: July 2004

This paper looks at the origins of ideas about community development as they emerged during Britain's administration of its African colonies from the 1920s to the 1950s. Significant influences on development policy and practice include changing ideas about state intervention within the British government, international scrutiny from international organizations, US interest in Africa, ideas and activities of missionary societies, technological developments, great leaps forward by key individuals, examples of state‐sponsored mass education schemes in Russia, colonial disturbances, and cataclysmic events such as the Great Depression, the rise of Hitler, and pre‐eminently, the Second World War itself. The evolution of community development ideas in Colonial Office practice will chiefly be illustrated through instructional films. Those which illustrate the argument are a striking example of community development in action because they are a visual medium in a visual age; they were seen as having a pivotal role in mass education schemes; they illustrate through their topics and scenarios what were seen as the hot development issues of the day; they capture the flavour of the period; and because they are a concrete illustration of the continuity of community development schemes in Africa in the colonial and post‐colonial eras.
Comparing the effectiveness of cognitive behaviour therapy using individual or group therapy in the treatment of depression
Authors: Lockwood Craig , Page Tamara , Conroy‐Hiller Tiffany
Published: July 2004

Executive summary

Objectives  The objective of this review was to present the best available information on the use of cognitive behaviour therapy using either group cognitive therapy (GCT) or individual cognitive therapy (ICT) in the treatment of depression. The primary question to be addressed in this review was: For the treatment of long‐term depression, using a cognitive behavioural approach, is group therapy or individual therapy the most effective?

Inclusion criteria  Studies that included adolescents or adults with long‐term depression and a measured Beck Depression Inventory (BDI) value of ≥12 or Hamilton Rating Scale for Depression (HRSD) of ≥14 were included. Interventions of interest were forms of cognitive behaviour therapy utilising either an individual or group approach. For the purpose of this review individual therapy was regarded as a one‐to‐one interaction between the patient and the therapist. Group therapy excluded family therapy. This review excluded studies that involved pharmacotherapy alone as the only intervention and studies that involved combined group and individual treatment. Outcome measures of interest were reduction in depression inventory scores, specifically the BDI and/or the HRSD. This study considered any randomised or pseudo‐randomised controlled trials that addressed the use or comparison of GCT or ICT.

Results  Individual and group cognitive behavioural therapies for moderately or severely depressed adults (BDI ≥ 14) were comparable with each other in effectiveness and both were superior to providing no treatment at all. Individual cognitive therapy was equal to or better than tricyclic antidepressant drugs given at recommended therapeutic dosages for depressed people with a mean BDI of 30. This information was based on level II evidence.

Recommendations  The following recommendations were made for adults:

Either GCT or ICT can be used to treat moderate to severe depression. The choice of therapy should be dependent upon the clinician's perceived receptiveness of the particular patient to group or individual treatment.

The use of computer‐assisted therapy is a useful adjunct to GCT in moderate to severely depressed patients.

ICT can effectively replace pharmacotherapy in moderate to severely depressed patients if the patient is opposed to being treated with drug therapy.

GCT has not been compared to pharmacotherapy so no direct recommendation can be given as to its effectiveness as a replacement therapy.

The following recommendations were made for adolescents:

Either GCT or ICT can be used to treat moderately depressed adolescents (BDI ≥ 14).

More research is needed to determine the effectiveness of GCT or ICT in severely depressed adolescents (BDI ≥ 20).
Understanding Barriers to Peace: Reflecting on Israeli–Palestinian Economic Negotiations
Authors: Bar‐Zion Bari
Published: July 2004

Drawing on relevant negotiations literature, this article describes some of the main barriers in the negotiation process between Israel and the Palestinian Authority as experienced by the author between the years 1998–2000. The analysis of these barriers is viewed through a prism of one case study: the negotiations regarding the economic component of the Wye River Memorandum. By subjecting that two‐year negotiation process to a reflective analysis, this article not only attempts to shed light on the case presented, but also to help identify a wider range of barriers and behaviors that characterize the ongoing negotiations between Israel and the Palestinian Authority.
Negotiating Integrative Medicine: A Framework for Provider–Patient Conversations
Authors: Cohen Michael H.
Published: July 2004

Efforts to integrate complementary and alternative medical (CAM) therapies into conventional medical settings are creating a variety of negotiation challenges between various stakeholders. Focusing on the two‐party encounter between physician and patient offers a way to understand the application of principled negotiation to perhaps the most fundamental and emotionally charged place within the health care system in which the introduction of CAM therapies is likely to disrupt relationships and produce conflict. This article suggest ways in which the theory and analysis of principled negotiation can add to current liability and ethical frameworks, and might thereby contribute to optimal future health care by helping to wisely integrate CAM therapies into conventional medical care.
Bringing Peace Into the Room
Authors: Fox Erica A.
Published: July 2004

What are the essential qualities a person needs to be an effective mediator? In addition to understanding conceptual frameworks and mastering fundamental skills of mediation, what role do the personal characteristics of the mediator play in the resolution of conflict? Bringing Peace Into the Room is a groundbreaking collection of essays addressing these questions. In a thoughtful and provocative way, the authors ask us to examine ourselves and our field. They invite us to consider the ways in which our own individual development as human beings impacts the parties and cases with whom we work. Ultimately, the book challenges us to re‐imagine our roles as mediators by asking us to internalize and to embody the highest principles of our profession.
Pheomelanin Coat Colour Dilution in French Cattle Breeds is not Correlated with the TYR, TYRP1 and DCT Transcription Levels
Authors: Guibert Sylvain , Girardot Michael , Leveziel Hubert , Julien Raymond , Oulmouden Ahmad
Published: July 2004

In this study we report the isolation of full‐length cDNAs and the expression patterns of TYR, TYRP1 and DCT in four e/e cattle breeds exhibiting different pheomelanic coat colours ranging from reddish brown to creamy white phenotypes. Predicted proteins encoded by bovine TYR, TYRP1 and DCT display high levels of homology and contain all characteristic domains shared between their mouse and human counterparts. The full expression of these three genes is observed in melanocytes of black areas of ED/ED Prim'Holstein's animals. On the other hand, e/e melanocytes of animals belonging to the Blonde d'Aquitaine (blond), Limousine (red) and Salers (reddish brown) breeds present different levels of down‐regulated TYR and DCT expression and a complete repression of TYRP1. Surprisingly, e/e melanocytes of animals belonging to the Charolais breed (creamy white) present an inverse relationship between TYR, TYRP1 and DCT expression and its lower melanogenic activity. The sum of these results shows that the dilution of the coat colour in French cattle breeds is not correlated with a transcription level of TYR family genes. Other possible modifier loci are suggested.
Direct Interaction of Sox10 with the Promoter of Murine Dopachrome Tautomerase (Dct) and Synergistic Activation of Dct Expression with Mitf
Authors: Jiao Zhongxian , Mollaaghababa Ramin , Pavan William J. , Antonellis Anthony , Green Eric D. , Hornyak Thomas J.
Published: July 2004

The murine dopachrome tautomerase (Dct) gene is expressed early in melanocyte development during embryogenesis, prior to other members of the tyrosinase gene family important for regulating pigmentation. We have used deletion mutants of the Dct promoter, transfections with developmentally relevant transcription factors, and gel shift assays to define transcriptional determinants of Dct expression. Deletion mutagenesis studies show that sequences within the proximal 459 nucleotides are critical for high level expression in melanocytic cells. This region of the promoter contains candidate binding sites for the transcription factors Sox10 and Mitf. Transfections into 293T and NIH3T3 cells show that Sox10 and Mitf independently activate Dct expression, and, when co‐transfected, synergistically activate Dct expression. To support the notion that Sox10 acts directly upon the Dct promoter to activate gene expression, direct interaction of Sox10 was demonstrated using gel shifts of oligonucleotide probes derived from promoter sequences within the region required for Sox10‐dependent induction. These results suggest that a combinatorial transcription factor interaction is important for expression of Dct in neural crest‐derived melanocytes, and support a model for sequential gene activation in melanocyte development whereby Mitf, a Sox10‐dependent transcription factor, is expressed initially before an early melanocyte differentiation gene, Dct, is expressed.
Down‐Regulated PAR‐2 is Associated in Part with Interrupted Melanosome Transfer in Pigmented Basal Cell Epithelioma
Authors: Sakuraba Kazuko , Hayashi Nobukazu , Kawashima Makoto , Imokawa Genji
Published: July 2004

In pigmented basal cell epithelioma (BCE), there seems to be an abnormal transfer of melanized melanosomes from proliferating melanocytes to basaloid tumor cells. In this study, the interruption of that melanosome transfer was studied with special respect to the altered function of a phagocytic receptor, protease‐activated receptor (PAR)‐2 in the basaloid tumor cells. We used electron microscopy to clarify the disrupted transfer at the ultrastructural level and then performed immunohistochemistry and reverse transcription‐polymerase chain reaction (RT‐PCR) to examine the regulation of a phagocytic receptor, PAR‐2, expressed on basaloid tumor cells. Electron microscopic analysis revealed that basaloid tumor cells of pigmented BCE have a significantly lower population of melanosomes (∼16.4%) than do normal keratinocytes located in the perilesional normal epidermis (∼91.0%). In contrast, in pigmented seborrheic keratosis (SK), a similarly pigmented epidermal tumor, the distribution of melanin granules does not differ between the lesional (∼93.9%) and the perilesional normal epidermis (∼92.2 %), indicating that interrupted melanosome transfer occurs in BCE but not in all pigmented epithelial tumors. RT‐PCR analysis demonstrated that the expression of PAR‐2 mRNA transcripts in basaloid cells is significantly decreased in pigmented BCE compared with the perilesional normal epidermis. In contrast, in pigmented SK, where melanosome transfer to basaloid tumor cells is not interrupted, the expression of PAR‐2 mRNA transcripts is comparable between the basaloid tumor cells and the perilesional normal epidermis. Immunohistochemistry demonstrated that basaloid cells in pigmented BCE have less immunostaining for PAR‐2 than do keratinocytes in the perilesional normal epidermis whereas in pigmented SK, there is no difference in immunostaining for PAR‐2 between the basaloid tumor and the perilesional normal epidermis. These findings suggest that the decreased expression of PAR‐2 in the basaloid cells is associated in part with the observed interruption of melanosome transfer in pigmented BCE.
Near Infrared Spectroscopy as a Tool for the Determination of Eumelanin in Human Hair
Authors: Zoccola Marina , Mossotti Raffaella , Innocenti Riccardo , Loria Dora I. , Rosso Stefano , Zanetti Roberto
Published: July 2004

Eumelanins are brown‐black pigments present in the hair and in the epidermis which are acknowledged as protection factors against cell damage caused by ultraviolet radiation. The quantity of eumelanin present in hair has recently been put forward as a means of identifying subjects with a higher risk of skin tumours. For epidemiological studies, chromatographic methods of determining pyrrole‐2,3,5‐tricarboxylic acid (PTCA; the principal marker of eumelanin) are long, laborious and unsuitable for screening large populations. We suggest near infrared (NIR) spectroscopy as an alternative method of analysing eumelanin in hair samples. PCTA was determined on 93 samples of hair by means of oxidizing with hydrogen peroxide in a basic environment followed by chromatographic separation. The same 93 samples were then subjected to NIR spectrophotometric analysis. The spectra were obtained in reflectance mode on hair samples which had not undergone any preliminary treatment, but had simply been pressed and placed on the measuring window of the spectrophotometer. The PTCA values obtained by means of HPLC were correlated with the near infrared spectrum of the respective samples. A correlation between the PTCA values obtained by means of HPLC and the PTCA values obtained from an analysis of the spectra was obtained using the principal component regression (PCR) algorithm. The correlation obtained has a coefficient of regression (R2) of 0.89 and a standard error of prediction (SEP) of 13.8 for a mean value of 108.6 ng PTCA/mg hair. Some considerations about the accuracy of the obtained correlation and the main sources of error are made and some validation results are shown.
Agonist‐Independent, High Constitutive Activity of the Human Melanocortin 1 Receptor
Authors: Sánchez‐Más Jesús , Hahmann Christa , Gerritsen Ineke , García‐Borrón José C , Jiménez‐Cervantes Celia
Published: July 2004

The melanocortins (α‐melanocyte‐stimulating hormone and adrenocorticotropin) act on epidermal melanocytes to increase melanogenesis, the eumelanin/pheomelanin ratio and dendricity. These actions are mediated by the heptahelical melanocortin 1 receptor (MC1R), positively coupled to adenylyl cyclase. Gain‐of‐function mouse Mc1r alleles are associated with a dark, eumelanic coat. Conversely, loss‐of‐function variants, or overexpression of agouti, a natural melanocortin antagonist, yield yellow, pheomelanic furs. In humans, loss‐of‐function MC1R variants are associated with fair skin, poor tanning, propensity to freckle and increased skin cancer risk. Therefore, MC1R is a key regulator of mammalian pigmentation. Several observations such as induction of constitutive pigmentation in amelanotic mouse melanoma cells following expression of MC1R indicate that the receptor might display agonist‐independent activity. We report a systematic and comparative study of MC1R and Mc1r constitutive activity. We show that expression of MC1R in heterologous systems leads to an agonist‐independent increase in cyclic adenosine monophophate (cAMP). Basal signalling is a function of receptor expression and is two to fourfold higher for MC1R than for Mc1r. Moreover, it is observed in human melanoma cells over‐expressing the MC1R. Constitutive signalling is abolished or reduced by point mutations of MC1R impairing the response to agonists, and is only doubled by the Lys94Glu mutation, mimicking the constitutively active mouse Eso‐3J allele. Stable or transient expression of wild‐type MC1R, but not of loss‐of‐function mutants, potently stimulates forskolin activation of adenylyl cyclase, a common feature of constitutively active Gs‐coupled receptors. Therefore, human MC1R displays a strong agonist‐independent constitutive activity.
25‐Hydroxycholesterol Acts in the Golgi Compartment to Induce Degradation of Tyrosinase
Authors: Hall Andrea M. , Krishnamoorthy Lalitha , Orlow Seth J.
Published: July 2004

Oxysterols play a significant role in cholesterol homeostasis. 25‐Hydroxycholesterol (25HC) in particular has been demonstrated to regulate cholesterol homeostasis via oxysterol‐binding protein and oxysterol‐related proteins, the sterol regulatory element binding protein, and the rate‐limiting enzyme of cholesterol biosynthesis, hydroxymethylglutaryl coenzyme A reductase. We have examined the effect of 25HC on pigmentation of cultured murine melanocytes and demonstrated a decrease in pigmentation with an IC50 of 0.34 μM and a significant diminution in levels of melanogenic protein tyrosinase. Pulse‐chase studies of 25HC‐treated cells demonstrated enhanced degradation of tyrosinase, the rate‐limiting enzyme of melanin synthesis, following endoplasmic reticulum (ER) and Golgi maturation. Protein levels of GS28, a member of an ER/cis‐Golgi SNARE protein complex, were also diminished in 25HC‐treated melanocytes, however levels of the ER chaperone calnexin and the cis‐Golgi matrix protein GM130 were unaffected. Effects of 25HC on tyrosinase were completely reversed by 4α‐allylcholestan‐3α‐ol, a sterol identified by its ability to reverse effects of 25HC on cholesterol homeostasis. Finally, the addition of 25HC to lipid deficient serum inhibited correct processing of tyrosinase. We conclude that 25HC acts in the Golgi compartment to regulate pigmentation by a mechanism shared with cholesterol homeostasis.
The Transcription Network Regulating Melanocyte Development and Melanoma
Authors: Vance Keith W. , Goding Colin R.
Published: July 2004

The enormous variety of pigmentation phenotypes in nature reflects a series of remarkable events that begin in the neural crest and end with the manufacture and distribution of pigment by mature melanocytes located in the epidermis and hair follicles. While the origins of melanoblasts from multipotent precursors in the neural crest is striking in itself, yet more so is the fact that these pioneer melanoblasts manage to undertake and survive their long migration, and in doing so proliferate and maintain their identity before ultimately arriving at their destination and undergoing differentiation. With the application of the powerful combination of genetics and molecular and cell biology the mystery surrounding the genesis of the melanocyte lineage is slowly being unravelled. At its heart is the powerful alliance between signal transduction and transcription that coordinates the program of gene expression that confers on a cell its identity, provides its passport for migration, and instructs it in the arts of survival and timely reproduction. The realization that the proliferation and migration of melanoblasts during development resembles closely the proliferation and metastasis of melanoma, a highly dangerous and increasingly common cancer, serves to highlight the value of the melanocyte system as a model for addressing key issues of general significance in both development and cancer.
Molecular Cloning, Gene Expression in Albino Mutants and Gene Knockdown Studies of Tyrosinase mRNA in Rainbow Trout
Authors: Boonanuntanasarn Surintorn , Yoshizaki Goro , Iwai Kenichi , Takeuchi Toshio
Published: July 2004

Tyrosinase has a role in melanin synthesis and several defects of the tyrosinase gene lead to albinism. Here, we cloned and characterized rainbow trout tyrosinase cDNAs and carried out the molecular and biochemical characterization of albino mutants. Two types of cDNA were cloned: tyrosinase‐1 (Tyr‐1) and tyrosinase‐2 (Tyr‐2). Both contained regions predicted to encode structural features of tyrosinase, and phylogenetic analysis confirmed that Tyr‐1 and Tyr‐2 were members of the tyrosinase family. Tyr‐1 transcripts were first detected in embryos at 5 d post‐fertilization (dpf) and Tyr‐2 transcripts at 15 dpf. 3,4‐dihydroxyphenylalanine assays revealed significantly reduced tyrosinase activities in dominant and recessive albino mutants compared with wild‐type embryos. However, reverse‐transcription PCR showed no differences in the amounts or lengths of the coding regions of Tyr‐1 and Tyr‐2 transcripts between wild‐type embryos and albino mutants. Antisense morpholino oligonucleotides (AMOs) designed to knockdown tyrosinase gene expression in wild‐type embryos led to reduced pigmentation in the retina and skin of embryos at 25 and 35 dpf, respectively. Furthermore, the tyrosinase activities of AMO‐treated embryos were significantly reduced. We conclude that both Tyr‐1 and Tyr‐2 are crucial for melanin synthesis in rainbow trout embryos. Furthermore, we describe a potential application of AMOs in the treatment of hyperpigmentation.
Genetics and Evolution of Pigment Patterns in Fish
Authors: Kelsh Robert N.
Published: July 2004

Vertebrate pigment patterns are both beautiful and fascinating. In mammals and birds, pigment patterns are likely to reflect the spatial regulation of melanocyte physiology, via alteration of the colour‐type of the melanin synthesized. In fish, however, pigment patterns predominantly result from positioning of differently coloured chromatophores. Theoretically, pigment cell patterning might result from long‐range patterning mechanisms, from local environmental cues, or from interactions between neighbouring chromatophores. Recent studies in two fish genetic model systems have made progress in understanding pigment pattern formation. In embryos, the limited evidence to date implicates local cues and chromatophore interactions in pigment patterning. In adults, de novo generation of chromatophores and cell–cell interactions between chromatophore types play critical roles in generating striped patterns; orientation of the stripes may well depend upon environmental cues mediated by underlying tissues. Further genetic screens, coupled with the routine characterization of critical gene products, promises a quantitative understanding of how striped patterns are generated in the zebrafish system. Initial ‘evo‐devo’ studies indicate how fish pigment patterns may evolve and will become more complete as the developmental genetics is integrated with theoretical modelling.
A Framework for Flexible Systems and Its Implementation in Multiattribute Decision Making
Authors: Olewnik Andrew , Brauen Trevor , Ferguson Scott , Lewis Kemper
Published: July 2004

In this paper, a framework for the concept of flexibility in complex system design is presented. This is one of the first of many steps toward developing new design methods for designers that will aid them in the development of customizable systems that meet the requirements of multiple customers and multiple tasks. The hope is that this paper will provide both a starting point from which academia and industry can move forward in developing new design methods for flexible systems and a basis for establishing a standard lexicon for use when referring to flexible system design.
Dynamic Analysis of Planar Cooperative Manipulators With Link Flexibility*
Authors: Zhang Cheng-Xin , Yu Yue-Qing
Published: July 2004

With the Timoshenko beam theory and the Finite Element Method, the dynamic equation of planar cooperative manipulators with link flexibility is proposed in absolute coordinates. Taking the actual position of the mass center of the cooperated object as the boundary condition, the inverse dynamic equation is developed with the load distribution method. With the solution of the inverse dynamic equations, the cooperated object can track a given trajectory accurately and the errors between the actual internal forces and the specified internal forces on the cooperated manipulators converge to zero. A new method is also developed for the optimum load distribution and load capacity of cooperative manipulator system. A numerical simulation of two planar flexible robot arms manipulating a rigid load is presented.
Modeling Spatial Displacements Using Clifford Algebra
Authors: Mullineux Glen
Published: July 2004

This paper looks at the use of a Clifford (or geometric) algebra for handling both rotations and translations in Euclidean space. The algebra is constructed over the real numbers using four basis vectors. Three of these generate a subalgebra which models three-dimensional space; the fourth acts as a projective coordinate. Spatial displacements are represented by bivectors of a certain form. The application to the generation of smooth motions using Be´zier and B-spline techniques is illustrated.