bluuebunny/crossref_metadata_2025 huggingface dataset:
Male competition is disruptive to courtship in the Pacific blue‐eye
Authors: Wong B. B. M.
Published: July 2004

The present study examined the effects of competition on male courtship in the Pacific blue‐eye Pseudomugil signifer, a species of fish where females have previously been shown to use courtship, but not male fighting prowess, as an important mate choice cue. Courtship bouts directed to a stimulus female were shortest when two males were allowed to freely interact (contact treatment) and longest when there was only one male (non‐interaction). Courtship length in trials where one of two males was confined to a clear cylinder (visual) was intermediate between the other two treatments. Courtship in visual and contact treatments was constantly disrupted. The percentage of interrupted courtships was higher for the contact compared to visual treatment where aggressive interactions were also longer in duration and took place more frequently. Within contact trials, dominant males courted longer than subordinates despite both males experiencing comparable rates of courtship disruption. These results suggest that male‐male competition can have important implications for adaptive female choice particularly in circumstances where the benefits being sought by females are unrelated to male fighting ability.
A review of the genusMalakichthysDöderlein (Perciformes: Acropomatidae) with the description of a new species
Authors: Yamanoue Y. , Matsuura K.
Published: July 2004

MalakichthysDöderlein, 1883, comprises seven species: type speciesMalakichthys griseusDöderlein 1883, from southern Japan to north‐western Australia;Malakichthys barbatusYamanoue & Yoseda, 2001, from southern Japan, the South China Sea, north‐western Australia and the Coral Sea;Malakichthys elegansMatsubara & Yamaguti, 1943, from southern Japan south to the Arafura Sea;Malakichthys levisYamanoue & Matsuura, 2001, from northern Australia;Malakichthys mochizukiYamanoue & Matsuura, 2001, from the Coral Sea;Malakichthys similissp. nov. from the Bohol Sea, Philippines;Malakichthys wakiyaeJordan & Hubbs, 1925, from southern Japan and Taiwan. Species ofMalakichthysare very similar to each other in general appearance but are distinguishable by spination on the lower jaw, features of the proximal‐middle radial of the first anal‐fin pterygiophore, the number of anal‐fin soft rays and body depth.
Free amino acids in Japanese eel eggs obtained by hormonal inducement
Authors: Seoka M. , Yamada S. , Kumai H.
Published: July 2004

Restriction proteolysis of the yolk proteins during the final oocyte maturation appears to result in the low content of free amino acids (FAA) and the unique FAA profile in Japanese eel Anguilla japonica eggs obtained by hormonal inducement.
Sexual Orientation and Demand for the Arts*
Authors: Lewis Gregory B. , Seaman Bruce A.
Published: July 2004

Objective. We establish and try to explain a gay affinity for the arts.

Methods. Using logit analysis on the General Social Survey, we test whether demographics, creativity, gender nonconformity, and sexual repression can explain differences between lesbians, gay men, and bisexuals (LGBs) and others in attendance at art museums, classical music concerts, and dance performances.

Results. LGBs' higher education and probability of being childless city‐dwellers explain one‐third of the substantial attendance differences. However, LGBs do not demonstrate higher innate creativity through greater amateur production of art; gay men's affinity for the arts appears no stronger than lesbians', casting doubt on the gender nonconformity explanation; and LGB‐straight attendance differences are as large among young as older respondents, despite supposed declines in the special functions of arts attendance since gay liberation.

Conclusions. LGBs are much more likely to attend the arts than demographically similar heterosexuals, but we find little support for three conventional explanations.
Knowledge Variables in Cross‐National Social Inquiry*
Authors: Mondak Jeffery J. , Canache Damarys
Published: July 2004

Objectives. This article examines the impact of “don't know” responses on cross‐national measures of knowledge regarding science and the environment. Specifically, we explore cross‐national variance in aggregate knowledge levels and the gender gap in knowledge in each of 20 nations to determine whether response‐set effects contribute to observed variance.

Methods. Analyses focus on a 12‐item true‐false knowledge battery asked as part of a 1993 International Social Survey Program environmental survey. Whereas most research on knowledge codes incorrect and “don't know” responses identically, we differentiate these response forms and develop procedures to identify and account for systematic differences in the tendency to guess.

Results. Substantial cross‐national variance in guessing rates is identified, variance that contributes markedly to variance in observed “knowledge” levels. Also, men are found to guess at higher rates than women, a tendency that exaggerates the magnitude of the observed gender gap in knowledge.

Conclusions. Recent research has suggested that “don't know” responses pose threats to the validity of inferences derived from measures of political knowledge in the United States. Our results indicate that a similar risk exists with cross‐national measures of knowledge of science and the environment. It follows that considerable caution must be exercised when comparing data drawn from different nations and cultures.
Faction in Movement: The Impact of Inclusivity on the Anti‐Globalization Movement*
Authors: Brooks D. Christopher
Published: July 2004

Objectives.This research examines and evaluates the reasons why the anti‐globalization movement has yet to make significant progress in achieving its primary goals of democratizing international trade negotiation processes.

Methods.Data on anti‐globalization protest cycles were collected from news sources for a time period of up to one month that encapsulated the protest events. From these, I constructed brief case narratives of the major events in Seattle, Washington, DC, Prague, Quebec City, Genoa, and Doha to illustrate my argument.

Results.I find that the democratic master frame employed by the movement results in two important limitations: (1) the movement cannot exclude participants without undermining its legitimacy, and (2) its lack of a centralized organizational framework makes it impossible to police the actions of participants during major protests. Recognizing these limitations, states hosting global economic summits have demonstrated increasingly a willingness to utilize repressive measures against the movement thereby undermining the movement's ability to achieve its goals.

Conclusion.I conclude that the inability of the anti‐globalization movement to exclude violent participants will continue to limit its effectiveness given states' increasing willingness to employ repressive tactics indiscriminately.
Apportioning the House of Representatives in 2000: The Effects of Alternative Policy Scenarios*
Authors: Baumle Amanda K. , Poston Dudley L.
Published: July 2004

Objective. The goal of this article is to develop and examine eight different scenarios in which the U.S. House of Representatives is reapportioned for the year 2000 on the basis of eight scenarios in which the apportionment population is differentially defined. In each scenario we adjust the 2000 apportionment population of each of the 50 states on the basis of various aspects of immigration, eligibility to vote, the overseas population, and statistical sampling.

Method. The method we use to apportion the House under each of the eight scenarios is the method of Equal Proportions, a divisor method that has been used to apportion the House since 1940. It endeavors to assign equitably to the 50 states, on the basis of population size, the 385 House seats that are available to be apportioned. Not all 435 House seats are assigned to the states using this method because each state automatically gets one seat.

Results. We show that when the House of Representatives is reapportioned on the basis of any of the eight scenarios, there is a varying amount of redistribution of seats among the states. Many states end up gaining or losing seats, but not all are affected.

Conclusion. There have been several legal challenges following the 2000 and earlier apportionments. The results of our analyses suggest that there will continue to be legal challenges to the 2000 and later apportionments. Since it is not likely that the Congress will permit a larger number of representatives than 435, apportionment challenges are really a zero‐sum game. Some states will gain political power, and others will lose it. This redistribution of power and its politically relevant consequences lead us to expect that apportionment challenges regarding the kinds of political and demographic issues raised in this article are not at all unlikely in the future.
Reinforcing Stereotypes? Race and Local Television News Coverage of Congress*
Authors: Schaffner Brian F. , Gadson Mark
Published: July 2004

Objective. Despite the increasingly diverse legislative records of African‐American members of Congress, much of the population continues to believe that African‐American legislators are interested only in minority issues. If African‐American House members are becoming more like their nonblack colleagues, then why do many citizens continue to hold these stereotypes about African‐American legislators?

Methods. We examine local television news coverage of House members and compare the coverage received by African‐American and nonblack incumbents.

Results. We find that local television newscasts devote more coverage to African‐American members of Congress but this coverage is also more race oriented, especially in less diverse markets. In fact, local television stations produce more race‐oriented coverage of African‐American legislators regardless of their legislative records on minority issues.

Conclusions. Local television news stations may be partially responsible for the prevailing stereotype of African‐American House members who are narrowly focused on race‐oriented issues.
Participation in Voluntary Youth‐Serving Associations and Early Adult Voting Behavior*
Authors: Frisco Michelle L. , Muller Chandra , Dodson Kyle
Published: July 2004

Objective. We investigate adolescent membership in voluntary associations and whether participation in these activities influences voting behavior during early adulthood.

Methods. Weighted logistic regression models predicting membership in voluntary associations and voting behavior were estimated using data from the National Educational Longitudinal Study of 1988–1994 (NELS).

Results. Our findings suggest that membership in voluntary associations varies by race and socioeconomic status (SES). In addition, membership in organizations historically rooted in moral development and civic socialization positively predict voter‐registration status and whether or not young adults participated in the first national election that they were eligible to vote in, but this relationship is moderated by both race and SES.

Conclusions. Our findings suggest that a large proportion of U.S. teenagers still participate in community‐based programs, many of which foster later civic participation, but that all youth do not equally benefit from participation.
Cross‐National Gender Variation in Environmental Behaviors*
Authors: Hunter Lori M. , Hatch Alison , Johnson Aaron
Published: July 2004

Objective. This article presents a cross‐national examination of gender variations in environmental behaviors. Research on environmental concern reveals modest distinctions between men and women, with women typically displaying higher levels of environmental concern and behavioral adjustments relative to men. Additionally, some prior research suggests that women appear more engaged in household‐oriented (private) pro‐environment behaviors (e.g., recycling), and men in community/society‐oriented (public) pro‐environment behaviors (e.g., protests). The analysis provided here offers an important extension to existing research through its cross‐cultural, comparative perspective.

Method. We make use of the 1993 International Social Survey to explore gender differences in “private” and “public” environmentally‐oriented behaviors across 22 nations.

Results. It is shown that women tend to engage in more environmental behaviors than men in many nations, particularly private behaviors. In addition, both women and men tend to engage in relatively more private environmental behaviors as opposed to public ones.

Conclusion. The cross‐national analysis provides support for gender distinctions with regard to some environmental behaviors within most of the incorporated 22 national contexts. Gender differences in level of private environmental behaviors tend to be more consistent within nations at the upper end of the wealth distribution.
Christian Fundamentalists and Public Opinion Toward the Middle East: Israel's New Best Friends?*
Authors: Mayer Jeremy D.
Published: July 2004

Objectives.Although Christian fundamentalist elites have become increasingly vocal in their support for Israel in the ongoing conflict in the Middle East, it is not clear that this rhetoric has produced differing attitudes about U.S. foreign policy in public opinion. This article examines whether such differences exist, and whether they are rooted in aspects of fundamentalist eschatology.

Methods.Data from a national telephone survey on attitudes toward the Middle East conflict and U.S. policy were examined using multivariate regression and means comparisons.

Results.These results demonstrate that Christian fundamentalists are the strongest supporters of Israel in America today. Fundamentalists have greater sympathy for Israel, oppose policies to pressure Israel, and are distinctive from all other groups in their high levels of support for continuing Israeli settlements in occupied Palestinian territories, as well as complete Israeli control of Jerusalem.

Conclusion.Christian fundamentalists in America are distinctive on this vital issue in American foreign policy because of their literal interpretation of the Bible or their leaders' increased cues on Middle East policies, or both. This suggests that religion is now an important factor in understanding public opinion on U.S. foreign policy in the region.
Expanding Discrimination Research: Beyond Ethnicity and to the Web*
Authors: Kuran Timur , McCaffery Edward J.
Published: July 2004

Objective. This article aims to expand research about perceptions of discrimination both substantively and methodologically beyond the domains of race and ethnicity, relying partly on web‐based surveys.

Methods. We conducted parallel surveys over the telephone and the World‐Wide Web, using standard random‐digit dial (RDD) techniques for the former, and a large volunteer panel for the latter.

Results. Both modes, phone and web, revealed that respondents consider discrimination based on physical appearance and economic status to be more prevalent than discrimination based on ethnicity. Respondents also reported that they themselves have been victimized more by physical appearance and economic‐status discrimination than by ethnic discrimination. Significant differences emerged between the phone and web respondent pools, even after controlling for such independent variables as age, race, education level, and gender.

Conclusions. People perceive discrimination across many aspects of social life, and appear more willing to reveal knowledge about controversial social phenomena on the web than on the phone.
The Impact of Church Activities and Socialization on African‐American Religious Commitment*
Authors: Wielhouwer Peter W.
Published: July 2004

Objective. This article examines religious commitment (church involvement, private devotionalism, and religious salience) among African Americans as a function of being served by a religious congregation, perception of the historical role of the church in relation to the group, and religious and racial socialization.

Methods. Drawing on traditional Christian expectations of the church, hypotheses are tested using the 1979–1980 National Survey of Black Americans. Three alternative models are tested that explicitly compare the effects of church activities with conventional socialization and demographic models of religious commitment.

Results. The results show that the church's fulfillment of its normative roles of discipleship and ministry is profoundly important for understanding religiosity, even controlling for other conventional predictors.

Conclusions. The analysis illustrates a central, and previously unaddressed, link between religious institutions and individual religiosity. The results have consequences for churches that might consider reprioritizing their activities in response to faith‐based initiatives because social‐service types of church activities influence religious commitment to a lesser degree than activities that emphasize spiritual growth.
The Intersection of Race and Gender: An Examination of Black Feminist Consciousness, Race Consciousness, and Policy Attitudes*
Authors: Simien Evelyn M. , Clawson Rosalee A.
Published: July 2004

Objective. In this article, we investigate black feminist consciousness, its relationship to race consciousness, and its impact on policy attitudes. Unlike scholars and activists who argue that black feminist consciousness detracts from race consciousness, we argue that the two go hand in hand.

Methods. Using confirmatory factor analysis, we examine public opinion survey data from the 1993 National Black Politics Study.

Results. We find that both black women and men have fairly high levels of support for black feminist ideals. Also, we provide evidence that black feminist consciousness is positively related to the components of race consciousness and demonstrate the influence of black feminist consciousness on support for abortion rights.

Conclusions. Our research is important because it uses a measure of black feminist consciousness true to its theoretical origins.
Unusual morphological and ecological characteristics of hyperbenthic juveniles of Gobius cruentatus
Authors: Kovačić M.
Published: July 2004

Unidentified hyperbenthic gobiid juveniles were collected while SCUBA diving at Oštro, in the Kvarner area, northern Adriatic Sea from 1996 to 2000. An additional 23 specimens of this form were collected at Oštro on 13 May 2002. They were kept alive and reared in the aquarium. Groups of specimens were sacrified periodically to study changes in morphology and growth. From the data acquired the hyperbenthic juveniles were identified as those of the red‐mouthed goby Gobius cruentatus. The present findings provide data on the unusual morphology and ecology of G. cruentatus juveniles.
The t(4;14) is associated with poor prognosis in myeloma patients undergoing autologous stem cell transplant
Authors: Chang Hong , Sloan Stephen , Li Dan , Zhuang Lihua , Yi Qi‐Long , Chen Christine I. , Reece Donna , Chun Kathy , Keith Stewart A.
Published: July 2004

The frequency and prognostic relevance of translocations t(11;14) and t(4;14), the most common translocations involving the immunoglobulin heavy chain (IgH) gene in multiple myeloma (MM), were investigated in 128 patients treated with intensive chemotherapy and autologous stem cell transplant. Myeloma cells were identified by cytoplasmic light chain immunofluorescence combined with fluorescence in situ hybridization (cIg‐FISH) for detection of translocations t(11;14) and t(4;14). Overall, t(11;14) was detected in 16 of 125 (12·8%) and t(4;14) in 15 of 120 (12·5%) patients. Progression‐free and overall survivals were similar for patients with or without t(11;14). However, patients with t(4;14) had significantly shorter progression‐free (median 9·9 months vs. 25·8 months; P = 0·0003) and overall survivals (median 18·3 months vs. 48·1 months; P < 0·0001) than patients without t(4;14). The t(4;14) was associated with IgA and t(11;14) with light chain MM. There was no association between the t(11;14) or t(4;14) and other biological parameters including age, gender, haemoglobin, β‐2 microglobulin, C‐reactive protein, calcium, creatinine, albumin, or the percentage of bone marrow plasma cells. Multivariate analysis identified t(4;14) as the only adverse prognostic factor for both progression‐free survival and overall survival. Our results indicate that the t(4;14) detected by cIg‐FISH is associated with a poor prognosis in MM patients receiving intensive chemotherapy and autotransplant.
Immunostimulating Agents: What Next?
Authors: Werner Georges H. , Jollès Pierre
Published: July 2004

Many chemical entities, either from natural sources or prepared by synthesis, are known to exert stimulating activities on various functions of the immune system, such as antibody production, resistance to infections, rejection of malignant cells, etc. In this review, the origin, chemical structures and main activities of several immunostimulants are described, with special emphasis on their present or potential medical usefulness. An attempt is made to envisage the future of this type of pharmacological agents, excluding however from the presentation the endogenous modulators of the immune system (cytokines), the production and activities of which are influenced by the immunostimulants themselves.
A Human Peroxisome‐Proliferator‐Activated Receptor‐γ is Activated by Inducers of Adipogenesis, Including Thiazolidinedione Drugs
Authors: Lambe Kevin G. , Tugwood Jonathan D.
Published: July 2004

We have cloned a human cognate of the mouse peroxisome‐proliferator‐activated receptor‐γ (hPPARγ) from a human placenta cDNA library. Sequence analysis reveals a high degree of similarity with the mouse receptor and, like other PPAR, hPPARγ forms heterodimers with the retinoid X receptor α(RXRα) and binds in vitro to DNA elements containing direct repeats of the sequence TGACCT. In common with mouse PPARγ, hPPARγ is expressed strongly in adipose tissue, but significant levels also are detectable in placenta, lung and ovary. In vitro trans ‐activation data suggest hPPARγ is only poorly activated by xenobiotic peroxisome proliferators, although certain fatty acids and eicosanoids are potent activators of this receptor. Both mouse and human PPARγ are capable of being activated by thiazolidinedione drugs, although the two receptors appear to differ in their sensitivity to these compounds. Taken together, these data suggest a high degree of structural and functional similarity between mouse and human PPARγ, and provide evidence for variation in human receptor structure which may result in differential sensitivity to activators.
Lipid Body Lipoxygenase Characterized by Protein Fragmentation, cDNA Sequence and very early Expression of the Enzyme during Germination of Cucumber Seeds
Authors: Höhne Michaela , Nellen Arndt , Schwennesen Karsten , Kindl Helmut
Published: July 2004

Lipid bodies are cellular compartments containing triacylglycerols. They are encompassed by a phospholipid monolayer and decorated with characteristic proteins. In plants, lipid bodies are synthesized during seed formation but acquire new proteins during seed germination. In germinating cucumber (Cucumis sativus) seeds, the set of newly synthesized proteins appearing in the lipid bodies at the early stage of triacylglycerol mobilization comprises a special form of lipoxygenase. We isolated the lipid body lipoxygenase and characterized fragments prepared by limited proteolysis and cleavage with cyanogen bromide. A very early expression of lipid body lipoxygenase was found by studying the rate of de novo synthesis of lipoxygenase forins during germination. This allowed a clear distinction of this enzyme from other lipoxygenase isoforms. Hence, for determining the molecular structure of lipid body lipoxygenase we analyzed a cDNA prepared from mRNA of cotyledons at day 1 of germination. From the cDNA sequence, oligonucleotides were derived that specifically detected lipid body lipoxygenase mRNA on nothern blots. The very early expression of lipid body lipoxygenase was corroborated by this approach. Good agreement was observed between the amino acid sequence deduced from the cDNA sequence and the peptide structures analyzed biochemically. In particular, the cleavage products of cyanogen bromide treatment indicated that we had isolated the lipid body lipoxygenase cDNA. The sequence data show a lipoxygenase form characterized by a molecular mass of 99655 Da, which is significantly higher than the molecular masses of the cytosolic forms. Compared to the cytosolic forms that exhibit a molecular mass of 95 kDa, the lipid body form has an N‐terminal extension of 34 amino acid residues. No evidence for a cotranslational or post‐translational proteolytic processing was obtained by the size comparison of the in vitro translated lipoxygenase and the lipid body form.
Different Effects of Insulin and Platelet‐Derived Growth Factor on Phosphatidylinositol 3‐Kinase at the Subcellular Level in 3T3‐L1 Adipocytes
Authors: Ricort Jean‐Marc , Tanti Jean‐François , Van Obberghen Emmanuel , Le Marchand‐Brustel Yannick
Published: July 2004

Insulin stimulates glucose uptake by induction of the translocation of vesicles that contain the glucose transporter Glut 4 to the plasma membrane. Phosphatidylinositol 3‐kinase (PtdIns 3‐kinase), which is thought to be involved in intracellular trafficking, could play a critical role in insulin‐induced glucose transport. In 3T3‐L1 adipocytes, insulin and platelet‐derived‐growth‐factor (PDGF) stimulated glucose uptake by 5.8‐fold and 2.4‐fold, respectively, but PDGF had no significant effect on Glut 4 translocation. Nevertheless, both hormones activated PtdIns 3‐kinase activity in total cell extracts. However, insulin and PDGF had different effects on the stimulation of PtdIns 3‐kinase activity in several subcellular fractions, and the movements of insulin‐receptor substrate (IRS) 1 and the p85 subunit of PtdIns 3‐kinase between subcellular compartments. PDGF stimulated PtdIns 3‐kinase activity almost exclusively in the plasma membrane, and induced translocation of the p85 subunit from the cytosol to the plasma membrane, where the PDGF receptor was phosphorylated on tyrosine residues. In contrast, insulin stimulated PtdIns 3‐kinase activity in the plasma membrane, in low‐density microsomes (LDM) and in cytosol. Furthermore, insulin induced the translocation of p85 from the cytosol to LDM and the translocation of IRS 1 from LDM to the cytosol. These data indicate that insulin and PDGF have different effects on the activation of PtdIns 3‐kinase and on the movement of IRS 1 and PtdIns 3‐kinase between subcellular compartments. We would like to suggest that a crucial event in the stimulation of glucose uptake by insulin could be that insulin, but not PDGF, induces activation of PtdIns 3‐kinase in the cytosol and in LDM, the compartment enriched in Glut‐4‐containing vesicles.
The Cooperation Between Two Silencers Creates an Enhancer Element that Controls Both the Lens‐Preferred and the Differentiation Stage‐Specific Expression of the Rat βB2‐Crystallin Gene
Authors: Dirks Ron P. H. , Kraft Harry J. , Van Genesen Siebe T. , Klok Erik J. , Pfundt Rolph , Schoenmakers John G. G. , Lubsen Nicolette H.
Published: July 2004

The rat βB2‐crystallin gene is active only during a specific stage of the differentiation of rat lens fibre cells directed by basic fibroblast growth factor. The regulatory elements that determine the transient activity of this gene are located in the ‐750/‐123 region and in the first intron. Singly, these elements act as silencers, together they constitute an enhancer that is active only during the specific differentiation stage. An additional silencer is found between ‐123 and ‐77. The proximal promoter region contains a Pax‐6 binding site at ‐65/‐51. In vitro, binding to this site could be detected but, according to in vivo footprinting experiments, this site is not occupied in the endogenous gene. Furthermore, co‐expression of Pax‐6 did not enhance promoter activity. Finally, mutation or deletion of this site did not affect promoter activity: the region ‐37/+10 sufficed for basal promoter activity. The cooperation between the ‐750/‐123 region and the first intron of the βB2‐crystallin gene not only determines the differentiation stage‐specific activity of the gene, but also contributes to the highly increased expression in lens cells compared with non‐lens cells.
A Model Relating Protein Osmotic Pressure to the Stiffness of the Cross‐Bridge Components and the Contractile Force of Skeletal Muscle
Authors: Grazi Enrico , Magri Ermes , Schwienbacher Christine , Trombetta Giorgio
Published: July 2004

We have modeled the effect of protein osmotic pressure on the orientation of the monomer in F‐actin, in tropomyosin‐F‐actin, in the myosin subfragment‐1 decorated F‐actin and in the myosin subfragment‐1 decorated tropomyosin‐F‐actin.

According to the model, at the physiological protein osmotic pressure (18 kPa), the elastic moduli by bending of the monomer in F‐actin and in tropomyosin‐F‐actin are calculated to be 4.74 MPa and 5.8 MPa, respectively. The elastic moduli by bending of the monomer in the myosin subfragment‐1 decorated F‐actin and in the myosin subfragment‐1 decorated tropomyosin‐F‐actin are calculated to be 22MPa and 22.3MPa, respectively. These latter values are in excellent agreement with the values of the elastic moduli by stretching found for the fibres of frog and rabbit muscle.

We have also calculated that, at the physiological protein osmotic pressure, the myosin subfragment‐1 decorated F‐actin rigor complex can develop a force of 3.96 pN, a force correctly oriented to promote the sliding of the actin filament toward the center of the sarcomere. The magnitude of this force is comparable to that reported for intact skeletal muscle. In contrast, the myosin subfragment‐1 decorated tropomyosin‐F‐actin rigor complex develops a much smaller driving force, that favours relaxation. Apparently tropomyosin uncouples the osmotic and the mechanical event.

It is proposed that the elastic energy for muscle contraction is provided by protein osmotic pressure.
Exchange of Regions of the Carboxypeptidase Y Propeptide
Authors: Ramos Cayo , Winther Jakob R.
Published: July 2004

The propeptide of carboxypeptidase Y from Succharomyces cerevisiae is important for folding of the enzyme. Previous work [Ramos, C., Winther, J. R. & Kielland‐Brandt, M. C. (1994) J. Biol. Chem. 269, 7006–70121] suggested that the sequences essential for in vivo folding were situated in the COOH‐proximal third of the propeptide. Concentrating on this region we have investigated the functionality of propeptide variants. Using a random mutagenesis approach we found that two segments can be defined: one in which there is a fairly high tolerance for substitution with unrelated sequences and another that has a more strict requirement for sequence conservation. Nevertheless, an overall lack of requirement for propeptide sequence conservation was found by substitution of the carboxypeptidase Y propeptide with that of a highly divergent propeptide sequence from an otherwise similar carboxypeptidase from Candida albicans. This propeptide was partially functional when combined with carboxypeptidase Y. Analysis of the biosynthesis of the mutant forms of the zymogen showed that a fraction of the molecules proceeded from the endoplasmic reticulum with fairly rapid kinetics, while the rest was degraded.
Molecular Characterization of a Tissue‐Polypeptide‐Specific‐Antigen Epitope and its Relationship to Human Cytokeratin 18
Authors: Rydlander Lars , Ziegler Elisabeth , Bergman Tomas , Schöberl Eva , Steiner Georg , Bergman Ann‐Charlotte , Zetterberg Anders , Marberger Michael , Björklund Peter , Skern Tim , Einarsson Roland , Jörnvall Hans
Published: July 2004

Tissue‐polypeptide‐specific antigen (TPS) from the human colon adenocarcinoma cell line WiDr was purified using the monoclonal antibody M3 as a probe. Upon SDS/polyacrylamide gradient gel electro‐phoresis, several TPS‐positive bands were detected (corresponding to 13 kDa, 22 kDa and a doublet at 42 kDa). The 13‐kDa moiety was purified about 30 000‐fold by a 5‐step protocol. The electro‐phoretically homogeneous component was obtained in a 7 % yield of the total TPS activity of the crude extract. N‐terminal sequence analysis showed the presence of an N‐terminally truncated molecule and identified the 13‐kDa TPS component as a fragment of human cytokeratin 18, with a major form starting at position 284 of the parent molecule. Laser‐desorption mass spectrometry showed the presence of one major component with a molecular mass corresponding to a C‐terminal end close to position 396 (which gives 12776 Da for the form with non‐truncated N‐terminus). The M3 antibody was also used to screen a human prostate cDNA λgt11 library. Four identical phage clones were detected, each producing a fusion protein with β‐galactosidase and the M3‐positive component. PCR amplification showed the presence of an approximately 1200‐bp insert, and sequence analysis revealed it to contain a 996‐nucleotide fragment corresponding to residues 103–429 of human cytokeratin 18 (plus a non‐coding human desmin artifact fragment). Smaller fragments, engineered by PCR and expressed as fusion proteins using the pET3xc vector in Escherichia coli, showed that the M3 epitope is localized to cytokeratin 18, residues 322–340. Two other TPS‐active monoclonal antibodies were localized to cytokeratin 18 with similar techniques, ascribing an epitope (to M21) to residues 414–429 and another (to M24) to residues 139–297. Combined, the results demonstrate that TPS reactivity is derived from specific epitopes of human cytokeratin 18.
Ras‐Dependent and Ras‐Independent Activation Pathways for the Stress‐Activated‐Protein‐Kinase Cascade
Authors: Kawasaki Hiroshi , Moriguchi Tetsuo , Matsuda Satoshi , Li Hong Zen , Nakamura Shun , Shtmohama Shun , Kimura Jun , Gotoh Yukiko , Nishida Eisuke
Published: July 2004

We have previously shown that osmotic stress activates both the mitogen‐activated protein kinase (MAPK) cascade and the stress‐activated protein kinase (SAPK, also known as JNK) cascade in rat fibroblastic 3Y1 cells and rat PC12 cells. Here, we show that treatment of these cells with sodium arsenite, a chemical compound that mimics the effects of heat shock, or anisomycin, a protein synthesis inhibitor, induces activation of SAPKs potently. These chemical compounds also stimulated the activity of SEKU MKK4/JNKK, SAPK activator, and the activity of MEKK, SEK1 activator. Expression of a dominant negative mutant of Ras blocked the anisomycin‐induced activation of SAPK and SEK1, but did not affect markedly the arsenite‐induced or heat shock‐induced activation in PC12 cells. The osmotic‐stress‐induced activation of SAPK was insensitive to the expression of a dominant negative Ras, but was partly sensitive to down‐regulation of protein kinase C. These results suggest the existence of Ras‐dependent and Ras‐independent activation pathways for the SAPK cascade triggered by environmental stresses including chemical stress in PC12 cells. Cell staining with a specific anti‐SAPK serum showed that SAPKs were present in both the cytoplasm and the nucleus under normal conditions, and became located mainly in the nucleus after osmotic stress or ultraviolet treatment, suggesting the nuclear translocation of SAPKs.
Molecular Characterization of Ceratotoxin C, a Novel Antibacterial Female‐Specific Peptide of the Ceratotoxin Family from the Medfly Ceratitis Capitata
Authors: Rosetto Marco , Manetti Andrea G. O. , Giordano Piero C. , Marri Laura , Amons Reinout , Baldari Cosima T. , Marchini Daniela , Dallai Romano
Published: July 2004

Ceratotoxins A and B are antibacterial peptides produced by the sexually mature females of Cerutitis capitata. The gene expression is restricted to the female reproductive accessory glands, and is not affected by bacterial infection, but is enhanced by mating. We report here the purification and the amino acid sequence of ceratotoxin C, a novel member of the ceratotoxin family, the cloning of its cDNA and the analysis of its expression. Ceratotoxin C is coordinately expressed with the other members of the ceratotoxin family. Its antibacterial activity is directed against both Gram‐negative and Gram‐positive bacterial strains but it is lower than that of ceratotoxin A. We demonstrate in the genome of C. capitata the presence of at least three ceratotoxin genes which express, in the female accessory glands, a set of peptides presumably involved in the protection of the genital tract during fertilization.
Threonine Autophosphorylation and Nucleotidylation of the Hepatic Membrane Protein PC‐1
Authors: Stefan Cristiana , Stalmans Willy , Bollen Mathieu
Published: July 2004

The membrane protein plasma‐cell‐differentiation antigen 1 (PC‐1) has been described as a phospho‐diesterase‐I/nucleotide pyrophosphatase and as an autophosphorylating protein kinase. It has been suggested, however, that PC‐1 is not a real protein kinase and that the autophosphorylated enzyme represents a nucleotidylated derivative, which is formed on Thr238 (murine PC‐1) as a catalytic intermediate during ATP hydrolysis [Belli, S. I., Mercuri, F. A., Sali, A. & Goding, J. W. (1995)Eur. J. Biochem. 228, 669–6761. We have investigated the proposed multifunctional role of PC‐1 and show here that ATP hydrolysis and autophosphorylation represent two distinct catalytic reactions. The enzyme was radiolabeled when various concentrations (1–260 μM) of [α‐32P]ATP or [α‐32P]ADP, but not [γ‐32P]ATP, were used as substrates for the formation of the pyrophosphatase catalytic intermediate, especially in the presence of imidazole, which interferes with the hydrolysis of the nucleotidylated enzyme. In contrast, autoradiography revealed autophosphorylation only with [γ‐32P]ATP as the phosphoryl donor, and autophosphorylation has been shown to occur only at ATP concentrations below 5 μM. Autophosphorylation could also be differentiated from nucleotidylation by its higher resistance to alkaline treatment and its more basic pH optimum. An intestinal nucleotide pyrophosphatase with a structurally related catalytic site could not be autophosphorylated, which shows that autophosphorylation is not an intrinsic property of the nucleotide pyrophosphatase reaction. Autophosphorylation of PC‐1 was associated with inactivation of its phosphodiesterase‐I/nucleotide‐pyrophosphatase activity. We propose that autophosphorylation of PC‐1 on Thr238 at low ATP concentrations serves as an autoregulatory mechanism that makes Thr238 unavailable for participation in the hydrolysis of extracellular nucleotides when they become scarce.
Xylose‐DNA: Comparison of the Thermodynamic Stability of Oligo(2′‐deoxyxylonucleotide) and Oligo(2′‐deoxyribonucleotide) Duplexes
Authors: Schöppe Arnulf , Hinz Hans‐Jürgen , Rosemeyer Helmut , Seela Frank
Published: July 2004

Measurements of differential scanning calorimetry, ultraviolet absorption and circular dichroism have been performed on two synthetic oligo(2′‐deoxyxylonucleotides): (A) d[(xA)3‐(xT)3‐(xA)3‐(xT)3‐T] and (B) d[(xA‐xT)6‐T], and on the oligo(2′‐deoxyribonucleotide) (C) d[(A)3‐(T)3‐(A)3‐(T)3]. Oligonucleotides having 2′‐deoxyxylose instead of 2′‐deoxyribose exhibit unusual thermodynamic, optical and structural features. At identical concentrations the transition temperatures of the oligo(2′‐deoxyxylooligomers) are higher than those of the oligo(2′‐deoxyribooligomers) indicating higher stability. The calorimetric transition enthalpy of (C) is 270 ± 15 kJ·mol−1, the corresponding van′t Hoff value is 280 ± 15 kJ·(mol of cooperative unit)−1. The ratio of ΔHvH/ΔHcal= 1.04 suggests all‐or‐none behaviour for the transition of the 2′‐deoxyribose oligonucleotide.

The analogous parameters of (A) are: ΔHcal= 310 ± 30 kJ·mol−1, ΔHvH= 220 ± 30 kJ·(mol of cooperative unit)−1. The ratio of 0.71 indicates multistate melting for this compound. The sequence dependence of the thermodynamic quantities becomes apparent when the parameters of the alternating oligo(2′‐deoxyxylonucleotide) d[(xA‐xT)6‐T] are compared to those of d[(xA)3‐(xT)3‐(xA)3‐(xT)3‐T]. The values of (B) are ΔHcal= 330 ± 30 kJ·mol−1; ΔHvH= 180 ± 15 kJ·(mol of cooperative unit)−1ΔHvH/ΔHcal= 0.55. The transition enthalpy of the alternating oligo(2′‐deoxyxylonucleotide) (B) is the highest but the cooperativity of transition is the lowest of the oligonucleotides studied. The circular dichroic spectra of the two oligo(2′‐deoxyxylonucleotides) show unusual features in that d[(xA)3‐(xT)3‐(xA)3‐(xT)3‐T] exhibits a spectrum that is suggestive of a left‐handed double helix, while the spectrum of the alternating oligo(2′‐deoxyxylonucleotide) (B) resembles neither that of (C) nor that of (A).
Brominated Detergents as Tools to Study Protein‐Detergent Interactions
Authors: de Foresta Béatrice , Legros Nathalie , Plusquellec Daniel , Le Maire Marc , Champeil Philippe
Published: July 2004

In order to study protein‐detergent short‐range interactions, we analyzed the quenching by brominated detergents of reticulum sarcoplasmic (SR) Ca2+‐ATPase intrinsic fluorescence. For this purpose, 7,8‐dibromododecyl β‐maltoside and 2‐O‐(10,11‐dibromoundecanoyl)sucrose, brominated analogs of two non‐ionic detergents, the frequently used dodecylmaltoside and the newly synthesized 2‐O‐lauroylsucrose respectively, were prepared.

Rayleigh scattering measurements showed that the brominated detergents efficiently and rapidly solubilized SR vesicles like their non‐brominated analogs although at slightly higher concentrations. Similarly, each analog had a slightly higher critical micellar concentration than its parent detergent. The partition coefficient K (expressed as the ratio of the molar fraction of detergent in the SR lipid phase to that in the aqueous phase, at pH 7.5 and 20°C) was similar for brominated and non‐brominated dodecyl maltoside (3.5–4 × 105) and slightly lower for dibromoundecanoylsucrose (≈105) than for lauroylsucrose (≈ 2 × 105).

At detergent concentrations too low to solubilize the membrane, the brominated detergents rapidly inserted (within seconds) into SR vesicles. In this concentration range, Ca2+‐ATPase fluorescence quenching steadily increased with detergent concentration. When the membrane was saturated with detergent, the residual fluorescence was about half of its initial value, indicating significant protein‐detergent contacts, possibly due to a slightly higher affinity of Ca2+‐ATPase for these detergents than for phospholipids. For higher detergent concentrations, solubilizing the membrane, the fluorescence continued to decrease with detergent concentration, with no evidence for a dramatic change in the average hydrophobic environment of the protein during the transition from bilayers to a soluble state. For still higher detergent concentrations, above that necessary for membrane solubilization, the fluorescence was further quenched to a residual relative value of about 20%, corresponding to further delipidation of the protein surface, in agreement with previous results [de Foresta, B., le Maire, M., Orlowski, S., Champeil, P., Lund, S., Møller, J. V., Michelangeli, F. & Lee, A. G. (1989)Biochemistry 28, 2558–25671. Fluorescence quenching for solubilized Ca2+‐ATPase was quickly reversed upon addition of excess non‐brominated detergent. The effects of the four detergents on the Ca2+‐ATPase hydrolysis of p‐nitrophenyl phosphate were similar and correlated with the protein‐detergent contacts evidenced above. In conclusion, both these brominated detergents appear to be promising tools to study protein‐detergent interactions at the hydrophobic surface of a membrane protein, either in a membrane or in solubilized complexes.
Identification of Hypoxically Inducible mRNAs in HeLa Cells Using Differential‐Display PCR
Authors: O'rourke John F. , Pugh Christopher W. , Bartlett Sylvia M. , Ratcliffe Peter J.
Published: July 2004

Oxygen is an important regulator of gene expression in mammalian cells, though the extent of operation and the organization of the inducible mechanisms involved are still largely undetermined. To define better the response to hypoxia, we have used differential display PCR to identify genes whose expression is induced in HeLa cells exposed to 1% oxygen. Among six genes whose induction by hypoxia was newly defined in this way, three were of known function, encoding the glucose transporter isoform 3 (Glut‐3), adenylate kinase isoenzyme 3 (AK‐3), and tissue factor, two were expressed sequence tags (ESTs), and one corresponded to a new sequence. One regulator of the transcriptional response to hypoxia has recently been identified as a heterodimeric DNA‐binding complex termed hypoxia‐inducible factor‐1 (HIF‐l), which is also inducible by the iron chelator, desferrioxamine. Of the six hypoxically regulated genes, at least four were also induced by exposure of the cells to desferrioxamine. To analyse further the mechanisms underlying induction of the genes identified in the differential display, inducible expression was compared in wild‐type mouse hepatoma cells (Hepa‐l), and mutant derivatives (c4) which fail to generate HIF‐1, due to a functional defect in one component, HIF‐1β. Two types of response were defined. For Glut‐3 and AK‐3, mutant (c4) cells showed almost complete loss of the inducible response to both hypoxia and desfemoxamine. In contrast, tissue factor mRNA was more inducible by both stimuli in c4 than wild‐type cells. These studies demonstrate the critical importance of HIF‐1β in newly recognized responses to hypoxia, and provide further evidence of the importance of this system of gene regulation in mammalian cells; they also demonstrate responses to both hypoxia and desfemoxamine which are independent of HIF‐1β and which appear exaggerated in HIF‐1β‐deficient cells.
Specific Binding of DnaA Protein to a DnaA Box in the GuaB Gene of Escherichia Coli K12
Authors: Tesfa‐Selase Fisehaye , Drabble William T.
Published: July 2004

Expression of the guaBA operon of Escherichia coli is regulated by the DNA replication‐initiating protein, DnaA. Two DnaA boxes, which are potential binding sites for DnaA, are present in the gua operon. One box (with 819 match to the DnaA box consensus sequence) is at the gua promoter; the other box, which has a consensus sequence, is on the non‐transcribed strand within the guaB coding region approximately 200 bp downstream of the initiation codon. The binding in vitro of purified DnaA protein to these boxes was investigated by filter retention and gel retardation analysis, and by deoxyribonuclease I footprinting, using restriction fragments of gua operon DNA. DnaA protein was shown to bind specifically only to the fragment carrying the consensus sequence DnaA box, and to protect this box from deoxyribonuclease I. Transcription termination resulting from the binding of DnaA to this box within the guaB gene explains repression by DnaA of the gua operon in vivo.