bluuebunny/crossref_metadata_2025 huggingface dataset:
12. YOUNG PEOPLE GET CLUED UP ABOUT CHLAMYDIA: AN INTERNET BASED RANDOMISED CONTROLLED TRIAL
Authors: Kang M. , Rochford A. , Mindel A. , Skinner S. R. , Webb M. , Hillier L. , Usherwood T.
Published: December 2007

Young people (16-25 years) are a target group for the prevention of Chlamydia trachomatis in the Australian national STI strategy. This study is a randomized controlled trial of an innovative internet-based intervention which aims to increase Chlamydia testing and treatment among at risk young people living in Australia. Study participation is via a website developed in consultation with young people and linked to an evaluated health promotion website. Young people in the intervention group receive personalised, confidential emails from a nurse or doctor while those in the control group receive automated emails. Follow up at 6 months will measure self-reported Chlamydia testing and other outcomes. By 5 June 2007, 359 young people of a target sample of 1000 were enrolled (83% female). Mean age is 20 years (range 16-25). Participants reside across all states and territories. Thirty percent of participants in the intervention group are in active email dialogue with the research nurse, e.g. “The research and...site was...really good,...it's kinda scared me into getting a test and just to get over the embarrassment... will the test be able to be part of just a normal appointment?” Zero participants in the control group have responded to the automated email. Baseline data and examples of the email interaction will be presented.
13. CAUGHT IN THE WEB: CYBERSEX AND ITS IMPACT ON INDIVIDUALS AND THEIR INTIMATE RELATIONSHIPS
Authors: Misso K. C.
Published: December 2007

With the current meteoric expansion in computer technology phonographic magazines and videos are fast being replaced by virtual intimacy and sex on the Internet. The affordability, accessibility and anonymity of the net offer a pseudo-intimacy less threatening and demanding than real life intimacy. The illusion of being in control, of constructing the relationship of your dreams can become quite addictive. This presentation will draw on current research and clinical data to illustrate how clients caught in the web find the compulsive behaviour patterns that emanate extremely destructive. With the passage of time such behaviour patterns can have a negative impact on an individual's psychological health, social relationships, work performance and most significantly, intimate relationships. The latter is a new factor contributing to distress in and the breakdown of couple relationships. The presentation highlights several 'warning signs' of a downward spiral and offers clinicians therapeutic strategies for working with couples caught up in this potential maelstrom. The computer hailed as a communication marvel, which was to facilitate 'connection', is fast becoming an instrument of 'disconnection' for those who are na�ve enough to ignore its darker side.
15. RISKS, CHOICES AND CONSEQUENCES: INTERNATIONAL STUDENTS AND SEXUAL HEALTH PROMOTION
Authors: Kalsi H. , Do H. , Gu Z.
Published: December 2007

International students are the 4th most revenue raising industry in Australia brining in $6 billion in 2006. December 2006 reports show 383 818 international students were enrolled across Australia with 61�019 in Queensland. The vast majority of students come from Asian countries with a high prevalence of HIV/AIDS and STIs combined with minimal sexual health knowledge.
Through workshops and discussion groups with international students they have been identified as a high risk in relation to sexual health problems due to their lack of sexual health knowledge, their tendency to engage in risk behaviour without adequate knowledge of risks, consequences and protection mechanisms. As a result, sexual health issues are increasingly presenting to professionals working directly with international students and health services in claims related to pregnancy, abortion rates, sexual assault, rape and reports of international students from high risk countries found to be HIV+.
Further, international students reported receiving no information prior to arrival and on arrival of risk behaviour, safety issues, health or laws in Australia. In order to promote safe sex behaviour among international students we have formulated various strategies to raise awareness of international students, from print material on arrival, to information stalls at O-week, intermittent workshops for international students, student leaders and professionals working directly with international students. The feedback from the students is very positive and new strategies are being developed to target students facing language barriers.
Our program findings demonstrate that the international student population is a high risk group facing sexual health issues where increased education and support must occur to prevent and reduce sexual health related problems.
19. INFECTIOUS SYPHILIS ELIMINATION FOR ABORIGINAL PEOPLE IN NSW: CHALLENGES AND OPPORTUNITIES
Authors: Spokes P. , Bartlett M. , Stewart K.
Published: December 2007

Elimination of syphilis within Aboriginal communities is one of the stated goals of the NSW Sexually Transmissible Infections Strategy 2006-2009. In 2007, a project was undertaken to inform strategy development to achieve the goal of elimination of infectious syphilis in Aboriginal communities.
Australian and international literature on elimination strategies for syphilis, STIs and other diseases was reviewed. Surveillance data were accessed through the National Notifiable Diseases Surveillance System and NSW Notifiable Disease Database and analysed to describe the current burden of disease. Key informants were consulted for advice on elimination strategies for infectious syphilis for Aboriginal people and possible barriers to the goal.
Infectious syphilis notifications for Aboriginal people have decreased significantly from 64% of all infectious syphilis cases in 1995 to 3% in 2006. For the rest of the population notifications have increased. Changes in male to female ratios and an increase in metropolitan notifications have been noted in recent years. Improvements in recording of Aboriginality information for infectious syphilis in NSW have allowed greater confidence in interpreting these trends. The role of accurate and complete surveillance information will play an important role in planning and directing the implementation of interventions to achieve the goal of syphilis elimination for Aboriginal people in NSW.
Challenges to the goal of elimination and the feasibility of a disease elimination strategy specific for Aboriginal people include issues of access to services for testing, diagnosis and treatment; cross-border mobility of Aboriginal people; prevalence of syphilis in the wider community; and continued access to accurate information. Lessons learned from international and Australian elimination strategies; burden of disease information; definition of elimination and target rates; challenges and strategies for achieving the goal of syphilis elimination and will be discussed.
27. CAN UNPROTECTED ANAL INTERCOURSE WITH REGULAR AND CASUAL PARTNERS EXPLAIN THE DIVERGING TRENDS IN HIV EPIDEMIC IN AUSTRALIA?
Authors: Zablotska I. , Prestage G. , Grulich A. , Imrie J. , Kippax S.
Published: December 2007

Introduction: Worldwide, increases in unprotected anal intercourse have been linked to the resurgence in HIV and STI in gay men. We assessed whether changes in UAI within regular and casual relationships may explain the diverging trends in HIV in three Australian states - NSW, Victoria and Queensland.
Methods: We used the data from the annual cross-sectional Gay Community Periodic Surveys conducted annually in Sydney since 1996 and in Melbourne and Queensland since 1998. A short self-administered questionnaire asks about HIV serostatus, sexual health testing and behaviours relevant to HIV epidemic. We present time trends in seroconcordance and unprotected sex with regular and casual partners.
Results: Currently, about one third of gay men report being in monogamous regular relationships, and this proportion has been slowly increasing everywhere. The self-reported UAI with regular partners (UAIR) was highest among men in seroconcordant positive relationships, lower among seroconcordant negative partners and lowest in non seroconcordant relationships. From 1998 to 2006, the rates of UAIR consistently increased by 10% in all three states and in all relationships by serostatus. The rates of UAI with casual partners (UAIC) were historically highest in NSW. From a peak in 2001, UAIC rates have consistently declined in NSW, but continuing increases were observed in Victoria and Queensland. Higher rates of nondisclosure of HIV were also observed in the context of UAIC in the latter two states.
Conclusion: Changes in unprotected sex with casual partners may be responsible for the slowing of HIV epidemic in NSW. Sustained investment in policies and programs are important in achieving behaviour change.
28. RISK TAKING AND SAFER SEX PRACTICES IN CASUAL RELATIONSHIPS BETWEEN MEN
Authors: Zablotska I. , Frankland A. , Prestage G. , Grulich A. , Imrie J.
Published: December 2007

Introduction: Universal condom use in casual sex is unlikely. We explored whether gay men lower the risk of HIV transmission during unprotected anal intercourse with casual partners (UAIC) by disclosing HIV serostatus and engaging in lower risk practices such as strategic positioning and/or withdrawal.
Methods: We used data from the annual cross-sectional Sydney Gay Community Periodic Survey. A short self-administered questionnaire collects information about HIV serostatus of the respondents, sexual practices with other men and other HIV-relevant behaviours. We present the prevalence of and time trends in disclosure of serostatus and the use of strategic positioning and withdrawal with casual partners.
Results: In 2006, 2568 men reported having had a casual partner in the 6 months before the survey. Disclosure was higher among men engaging in UAIC (68.4%) compared to those who always used condoms (49.7%). This relationship was more apparent amongst HIV-positive than negative men, of whom 83.5% and 63.9%, respectively, reported any disclosure. Over time, HIV-positive and negative men have increasingly reported disclosing to 'all' of their casual partners (p�<�0.01). HIV-positive men were less likely to report insertive-only positioning during UAIC (8.9%) compared to HIV-negative men (39.2%), with no changes emerging since over time. Significant increases were also noted in the proportion of HIV-positive men reporting withdrawal during insertive-UAIC (p�<�0.001) and HIV-negative men reporting withdrawal during receptive-UAIC (p�<�0.001).
Conclusion: In the context of UAIC, gay men appear to be employing a range of risk-reduction strategies. Increasing levels of disclosure and/or practices such as strategic positioning and withdrawal demonstrate the complexity of gay men's construction of, and engagement with, risk associated with HIV transmission. A more thorough understanding of these practices is essential for ongoing education and prevention.
31. WHY HAS TRICHOMONAS VAGINALIS DECLINED DRAMATICALLY AMONG VICTORIAN WOMEN (1947-2005)?
Authors: Marrone J. , Fairley C. K. , Saville M. , Bradshaw C. , Bowden F. J. , Donovan B. , Hocking J. S.
Published: December 2007

Trichomonas vaginalis (TV) diagnosis rates have decreased considerably in some countries during the last two decades. It is unclear why TV has decreased only in some countries. This study investigated the relationships between: 1) TV diagnosis rates among women attending the Melbourne Sexual Health Centre (MSHC), and among Pap smears screened by Victorian Cytology Services (VCS); 2) the use of nitroimidazoles in Australia and; 3) gonorrhoea notification data for Victoria to assess changes in sexual behaviour.
TV diagnosis rates among women attending MSHC rose from under 5% in the 1940's, to 20% to 30% in the 1960's and then declined 5% to 10% during the 1970's. From 1980 onwards, TV diagnosis rates fell progressively to below 1% by 1991, with 0.1% in 2004. A similar pattern was seen in TV at VCS, but with lower absolute percentages. Metronidazole was introduced into Australia in 1961 and tinidazole in 1976 and by 1987 there were 400 000 nitroimidazole prescriptions per year. Pap smear screening in Victoria began in 1965, only including 20% of women per year (aged 15 to 69) by the mid 1980's. Post 1980's, screening rose until 2000, stabilising at 35% of women per year. Gonorrhoea notification rates peaked during times TV was experiencing its greatest falls.
The initial decline of TV seen in Victoria was associated with the introduction of effective antibiotics. The further decline to less than 1% was seen when Pap smear screening participation increased during the 1990's.
33. WHAT WOMEN WANT WHEN FACED WITH AN UNPLANNED PREGNANCY
Authors: Michelson J.
Published: December 2007

Objective: To collect data in regards to:
women's experience of/desire for emotional support and information when faced with an unplanned pregnancy;
women's desire for counselling to support their decision-making, and the kind of counselling they want.
Methodology:
6593 women received an email invitation to complete the online survey.
2003 responded.
1022 had experienced an unplanned pregnancy, therefore qualifying.
Participating women were of reproductive age, drawn nationally.
Key findings published in November 2006.
Summary of results:
At any given time amongst a sample of women of reproductive age, just over half (51%) have experienced an unplanned pregnancy.
75% of women did not wish to speak to a counsellor before making a decision on how to proceed with an unplanned pregnancy.
Parenting was the most (56%) and adoption the least (2%) popular choice for resolving an unplanned pregnancy.
81% of women said it was important that a pregnancy counsellor refer for all three options - abortion, adoption and parenting.
21% of women sought information to assist their decision-making from their spouses/partners/biological father, while their local GP was the port of call for 17% of women facing an unplanned pregnancy. 13% of women stated that they did not need to seek any additional information to assist with their decision-making.
Conclusion:
Unplanned pregnancy is a key health issue for Australian women.
While pregnancy counselling should be available to women, it would be mistaken to see it as desired or required in all circumstances and it should be regulated.
There is a need for increased resources to be directed towards lowering contraceptive failure rates, and greater access to sexual health services.
38. GIVING HIV RESULTS. IS IT TIME TO CHANGE OUR THINKING?
Authors: Healey L. M. , O'Connor C. C.
Published: December 2007

Sydney's Inner West has the second highest number of new HIV diagnosis in NSW. This paper describes a cross-sectional audit of 200 HIV tests performed by the Sexual Health Service. How many people returned in person specifically for their HIV results? What were the risk factors of those who attended for their result? Were those who returned for their result first-time patients or those having repeat tests? What procedures were followed for those with a positive result? Given the demands on staff to efficiently utilise their time, a more individually tailored approach to giving HIV results including giving results over the telephone, may be a better way to manage the increasing number of HIV tests being performed at an inner city sexual health service.
41. CIRCUMCISION AND RISK OF HIV SEROCONVERSION IN THE HIM COHORT OF HOMOSEXUAL MEN IN SYDNEY
Authors: Templeton D. J. , Jin F. , Prestage G. P. , Donovan B. , Kippax S. C. , Imrie J. , Kaldor J. M. , Grulich A. E.
Published: December 2007

Objectives: We examined circumcision as a risk factor for HIV seroconversion in a community-based cohort of homosexual men in Sydney.
Methods: Between 2001 and 2004, 1427 initially HIV-negative men were enrolled. Circumcision status was self-reported at baseline, and self-report was validated by clinical examination during study visits in a sub-sample of approximately 300 participants. All participants were tested annually for HIV and offered testing for other sexually transmitted infections (STIs). Detailed information on sexual risk behaviours was collected every 6 months.
Results: At baseline, 66% of participants reported being circumcised; mostly as infants. The proportion circumcised ranged from 83% in those aged 45 or more to only 50% in those aged less than 25 (p�<�0.0001). There were 49 HIV seroconversions through 2006, an incidence of 0.80 per 100 person years (PY). Anorectal gonorrhoea and anal warts were independent risk factors for HIV infection. Overall, being circumcised was not related to HIV infection (relative risk (RR) 1.07, 95% CI 0.56-2.06). After controlling for non-concordant unprotected anal intercourse (UAI), anorectal STIs and age, there remained no association with circumcision (RR�=�0.88, 95% CI 0.45-1.74). Only nine of the 49 seroconversions occurred among men who reported no receptive UAI, an incidence of 0.35 per 100PY. In this group, circumcision was also not associated with HIV seroconversion (RR�=�0.99, 95% CI 0.25-3.96).
Conclusion: Overall, circumcision status was not associated with HIV seroconversion. In addition, analyses limited to those men who reported no receptive UAI, who are more likely to have been infected through insertive sex, suggest that circumcision may not reduce HIV risk even for insertive anal intercourse. Other preventive strategies are required to reduce HIV incidence in homosexual men.
63. A FEMINIST EXPLORATION OF WOMEN'S EXPERIENCES OF HAVING A SEXUALLY TRANSMITTED INFECTION
Authors: East L. S. , Peters K. , O'Brien L. , Jackson D.
Published: December 2007

Background and objectives: Sexually transmitted infections (STIs) affect millions of people worldwide and are capable of causing significant physical and psychological harm to individuals and communities. Although STIs can affect any sexually active individual they have more severe consequences for women compared to men, and are capable of causing infant death, infertility, and reproductive cancer. Despite the increasing prevalence of STIs, issues associated with the mental health consequences of these infections remain largely unexplored. However the negative impact on self-esteem and the stigma associated with STIs have been identified as important factors affecting the psychological wellbeing of individuals. This study aims to explore women's experiences and perceptions of having an STI from a feminist perspective. This paper will present initial findings.
Methodology: This study utilised a feminist methodology. Data was obtained through qualitative open-ended interviews with the women participants either in person or online and all data was subjected to feminist narrative analysis.
Results and conclusion: Data collection and analysis is in progress at the time of abstract submission. It is anticipated that preliminary results will be presented at this sexual health conference. Initial analysis has revealed that stigma, condom negotiation, self-blame, and acceptance/empowerment are major themes within the women participants' stories. This research will contribute to the existing body of literature and provide information to facilitate appropriate care provided by healthcare personnel through gaining insights and understanding into the needs of these women.
64. DOES CIRCUMCISION MAKE A DIFFERENCE TO THE SEXUAL EXPERIENCE OF GAY MEN? FINDINGS FROM THE HEALTH IN MEN (HIM) COHORT
Authors: Mao L. , Imrie J. , Prestage G. , Grulich A. , Donovan B. , Kaldor J. , Kippax S.
Published: December 2007

The relevance of circumcision in preventing HIV male-to-male sex transmission is poorly understood, in particular because any potential effect could be obscured by sexual practice as a mediating or confounding factor.
Using data from the Health in Men (HIM) cohort of 1426 HIV-negative homosexually active men in Sydney, we compared the sexual practices and sexual experiences of circumcised and uncircumcised men.
Overall 66% of men (n�=�939) in the cohort were circumcised. After adjusting for age and ethnicity, we found no difference between circumcised and uncircumcised men in anal sexual practices, difficulty using condoms, or sexual difficulties (e.g. loss of libido). Among the circumcised men, we compared those circumcised at infancy (n�=�854) with those circumcised after infancy (n�=�81). The majority cited phimosis (i.e., an inability to fully retract the foreskin) and parents' decision as the main reasons for circumcision after infancy. After adjusting for age and ethnicity, men circumcised after infancy were more likely to practise receptive anal sex (88% vs 75%, p�<�0.05) and to experience erection difficulties (52% vs 47%, p�<�0.05); but less likely to practise insertive anal sex (79% vs 87%, p�<�0.05) and to experience premature ejaculation (15% vs 23%, p�<�0.05) than those circumcised at infancy.
Our data suggest that overall circumcision status does not affect HIV-negative gay men's anal sexual practices, experience of condom use or likelihood of sexual difficulties. However, there is some suggestion of differences between circumcised men depending on the age at circumcision.
Scaling and efficiency determine the irreversible evolution of a market
Authors: Baldovin F. , Stella A. L.
Published: December 2007

In setting up a stochastic description of the time evolution of a financial index, the challenge consists in devising a model compatible with all stylized facts emerging from the analysis of financial time series and providing a reliable basis for simulating such series. Based on constraints imposed by market efficiency and on an inhomogeneous-time generalization of standard simple scaling, we propose an analytical model which accounts simultaneously for empirical results like the linear decorrelation of successive returns, the power law dependence on time of the volatility autocorrelation function, and the multiscaling associated to this dependence. In addition, our approach gives a justification and a quantitative assessment of the irreversible character of the index dynamics. This irreversibility enters as a key ingredient in a novel simulation strategy of index evolution which demonstrates the predictive potential of the model.
Loss of skeletal muscle strength by ablation of the sarcoplasmic reticulum protein JP45
Authors: Delbono Osvaldo , Xia Jinyu , Treves Susan , Wang Zhong-Min , Jimenez-Moreno Ramon , Payne Anthony M. , Messi María Laura , Briguet Alexandre , Schaerer Florian , Nishi Miyuki , Takeshima Hiroshi , Zorzato Francesco
Published: December 2007

Skeletal muscle constitutes ≈40% of the human body mass, and alterations in muscle mass and strength may result in physical disability. Therefore, the elucidation of the factors responsible for muscle force development is of paramount importance. Excitation–contraction coupling (ECC) is a process during which the skeletal muscle surface membrane is depolarized, causing a transient release of calcium from the sarcoplasmic reticulum that activates the contractile proteins. The ECC machinery is complex, and the functional role of many of its protein components remains elusive. This study demonstrates that deletion of the gene encoding the sarcoplasmic reticulum protein JP45 results in decreased muscle strength in young mice. Specifically, this loss of muscle strength in JP45 knockout mice is caused by decreased functional expression of the voltage-dependent Ca
2+
channel Ca
v
1.1, which is the molecule that couples membrane depolarization and calcium release from the sarcoplasmic reticulum. These results point to JP45 as one of the molecules involved in the development or maintenance of skeletal muscle strength.
Metabotyping of
Caenorhabditis elegans
reveals latent phenotypes
Authors: Blaise Benjamin J. , Giacomotto Jean , Elena Bénédicte , Dumas Marc-Emmanuel , Toulhoat Pierre , Ségalat Laurent , Emsley Lyndon
Published: December 2007

Assigning functions to every gene in a living organism is the next challenge for functional genomics. In fact, 85–90% of the 19,000 genes of the nematode
Caenorhabditis elegans
genome do not produce any visible phenotype when inactivated, which hampers determining their function, especially when they do not belong to previously characterized gene families. We used
1
H high-resolution magic angle spinning NMR spectroscopy (
1
H HRMAS-NMR) to reveal the latent phenotype associated to superoxide dismutase (
sod
-1) and catalase (
ctl
-1)
C. elegans
mutations, both involved in the elimination of radical oxidative species. These two silent mutations are significantly discriminated from the wild-type strain and from each other. We identify a metabotype significantly associated with these mutations involving a general reduction of fatty acyl resonances from triglycerides, unsaturated lipids being known targets of free radicals. This work opens up perspectives for the use of
1
H HRMAS-NMR as a molecular phenotyping device for model organisms. Because it is amenable to high throughput and is shown to be highly informative, this approach may rapidly lead to a functional and integrated metabonomic mapping of the
C. elegans
genome at the systems biology level.
Structural insight into distinct mechanisms of protease inhibition by antibodies
Authors: Wu Yan , Eigenbrot Charles , Liang Wei-Ching , Stawicki Scott , Shia Steven , Fan Bin , Ganesan Rajkumar , Lipari Michael T. , Kirchhofer Daniel
Published: December 2007

To better understand how the relatively flat antigen-combining sites of antibodies interact with the concave shaped substrate-binding clefts of proteases, we determined the structures of two antibodies in complex with the trypsin-like hepatocyte growth-factor activator (HGFA). The two inhibitory antibodies, Ab58 and Ab75, were generated from a human Fab phage display library with synthetic diversity in the three complementarity determining regions (H1, H2, and H3) of the heavy chain, mimicking the natural diversity of the human Ig repertoire. Biochemical studies and the structures of the Fab58:HGFA (3.5-Å resolution) and the Fab75:HGFA (2.2-Å resolution) complexes revealed that Ab58 obstructed substrate access to the active site, whereas Ab75 allosterically inhibited substrate hydrolysis. In both cases, the antibodies interacted with the same protruding element (99-loop), which forms part of the substrate-binding cleft. Ab58 inserted its H1 and H2 loops in the cleft to occupy important substrate interaction sites (S3 and S2). In contrast, Ab75 bound at the backside of the cleft to a region corresponding to thrombin exosite II, which is known to interact with allosteric effector molecules. In agreement with the structural analysis, binding assays with active site inhibitors and enzymatic assays showed that Ab58 is a competitive inhibitor, and Ab75 is a partial competitive inhibitor. These results provide structural insight into antibody-mediated protease inhibition. They suggest that unlike canonical inhibitors, antibodies may preferentially target protruding loops at the rim of the substrate-binding cleft to interfere with the catalytic machinery of proteases without requiring long insertion loops.
Human cytomegalovirus uses two distinct pathways to enter retinal pigmented epithelial cells
Authors: Wang Dai , Yu Qian-Chun , Schröer Jörg , Murphy Eain , Shenk Thomas
Published: December 2007

Human cytomegalovirus infects multiple cell types, including fibroblasts and epithelial cells. It penetrates fibroblasts by fusion at the cell surface but is endocytosed into epithelial cells. In this report, we demonstrate by electron microscopy that the virus uses two different routes to enter retinal pigmented epithelial cells, depending on the cell type in which the infecting virus was produced. Virus produced in epithelial cells preferentially fuses with the plasma membrane, whereas fibroblast-derived virus mostly enters by receptor-mediated endocytosis. Treatment of epithelial cells with agents that block endosome acidification inhibited infection by virus produced in fibroblasts but had only a modest effect on infection by virus from epithelial cells. Epithelial cell-generated virions had higher intrinsic “fusion-from-without” activity than fibroblast-generated particles, and the two virus preparations triggered different cellular signaling responses, as evidenced by markedly different transcriptional profiles. We propose that the cell type in which a human cytomegalovirus particle is produced likely influences its subsequent spread and its contribution to pathogenesis.
Protein characterization of
Saccharomyces cerevisiae
RNA polymerase II after
in vivo
cross-linking
Authors: Tardiff Daniel F. , Abruzzi Katharine C. , Rosbash Michael
Published: December 2007

To characterize proteins associated with active transcription complexes, we purified RNA polymerase II (pol II) from
Saccharomyces cerevisiae
after fixing live cells with formaldehyde. The approach mimics ChIP and requires solubilizing cross-linked complexes with sonication. Pol II was affinity-purified, and associated proteins were identified by MS. Several classes of proteins depended on cross-linking, including Mediator, general transcription factors, elongation factors, ribonucleoprotein particle (RNP) proteins, and histones. A tagged RNP protein reciprocally purified pol II under identical cross-linking conditions, and the association between RNP proteins and pol II was largely RNase-sensitive. The data indicate that the cross-linked Pol II purification contains elongating pol II with associated nascent RNP. Consistent with this view, some elongation factors no longer associate with pol II after inactivation of transcription in the temperature-sensitive pol II mutant,
rpb1-1
. Taken together, our data suggest that the cross-linked pol II purification contains a mixed population of pol II, including initiating pol II and elongating pol II.
Pathways to Nicotine Dependence in African American and Puerto Rican Young Adults
Authors: Brook Judith S. , Duan Tao , Brook David W. , Ning Yuming
Published: December 2007

This investigation examined the pathways to nicotine dependence among a sample of inner city African‐American and Puerto Rican young adults (mean age = 26.1 years, SD = 1.4 years). Four hundred and seventy‐five young adults were interviewed. The findings based on structural equation models showed that family conflicts, parental tobacco use, and weak ethnic identity were associated with vulnerable personality attributes and drug use, which in turn were related to nicotine dependence. Prevention strategies in young adults aimed at family conflicts, parental tobacco use, vulnerable personality attributes, drug use, weak ethnic identity, and socioeconomic status should be effective in reducing risks for nicotine dependence.
Telephone Enhancement of Long‐term Engagement (TELE) in Continuing Care for Substance Abuse Treatment: A NIDA Clinical Trials Network (CTN) study
Authors: Hubbard Robert L. , Leimberger Jeffrey D. , Haynes Louise , Patkar Ashwin A. , Holter John , Liepman Michael R. , Lucas Kathi , Tyson Breque , Day Tammy , Thorpe Elizabeth A. , Faulkner Briar , Hasson Albert
Published: December 2007

The TELE study examined the feasibility and potential efficacy of phone calls to patients after discharge from short‐ term inpatient and residential substance abuse treatment programs to encourage compliance with continuing care plans. After review of their continuing care plans, 339 patients from four programs were randomized either to receive calls or to have no planned contact. Ninety‐two percent of patients randomized to receive calls received at least one call. No difference was found between groups in self‐reported attendance at one or more outpatient counseling sessions after discharge (p = .89). When program records of all participants were examined, those receiving calls had a greater likelihood of documented attendance (48%) than those not called (37%). Results were not statistically significant (p < .003) because of the Hochberg correction for multiple tests. While the phone calls were feasible, the lack of clear evidence of efficacy of the calls suggests the need for further investigation of the role of telephone intervention to encourage compliance and improve outcomes.
Childhood Sexual and Physical Abuse Histories, PTSD, Depression, and HIV Risk Outcomes in Women Injection Drug Users: A Potential Mediating Pathway
Authors: Plotzker Rosalyn E. , Metzger David S. , Holmes William C.
Published: December 2007

We explored links between childhood sexual abuse (CSA), childhood physical abuse (CPA), posttraumatic stress disorder (PTSD)/depression, and women injection drug users' (IDUs') risk in 113 women recruited from two syringe exchange sites. More than half (56%) reported CSA, 68% CPA, 23% likely were depressed‐only, and 53% likely had PTSD/depression. CSA was associated with sexual (p = 0.003) and drug risk (p = 0.05); CPA was not. CSA was associated with PTSD/depression (p = 0.03); PTSD/depression was associated with sexual (p < 0.01) and drug (p < 0.03) risk. After PTSD/depression adjustment, CSA was no longer associated with sexual or drug risk. These results suggest that women IDUs' CSA‐to‐risk path is mediated by PTSD/depression.
Vinculin controls focal adhesion formation by direct interactions with talin and actin
Authors: Humphries Jonathan D. , Wang Pengbo , Streuli Charles , Geiger Benny , Humphries Martin J. , Ballestrem Christoph
Published: December 2007

Focal adhesions (FAs) regulate cell migration. Vinculin, with its many potential binding partners, can interconnect signals in FAs. Despite the well-characterized structure of vinculin, the molecular mechanisms underlying its action have remained unclear. Here, using vinculin mutants, we separate the vinculin head and tail regions into distinct functional domains. We show that the vinculin head regulates integrin dynamics and clustering and the tail regulates the link to the mechanotransduction force machinery. The expression of vinculin constructs with unmasked binding sites in the head and tail regions induces dramatic FA growth, which is mediated by their direct interaction with talin. This interaction leads to clustering of activated integrin and an increase in integrin residency time in FAs. Surprisingly, paxillin recruitment, induced by active vinculin constructs, occurs independently of its potential binding site in the vinculin tail. The vinculin tail, however, is responsible for the functional link of FAs to the actin cytoskeleton. We propose a new model that explains how vinculin orchestrates FAs.
Mutual information without the influence of phylogeny or entropy dramatically improves residue contact prediction
Authors: Dunn S.D. , Wahl L.M. , Gloor G.B.
Published: December 2007

Motivation: Compensating alterations during the evolution of protein families give rise to coevolving positions that contain important structural and functional information. However, a high background composed of random noise and phylogenetic components interferes with the identification of coevolving positions.

Results: We have developed a rapid, simple and general method based on information theory that accurately estimates the level of background mutual information for each pair of positions in a given protein family. Removal of this background results in a metric, MIp, that correctly identifies substantially more coevolving positions in protein families than any existing method. A significant fraction of these positions coevolve strongly with one or only a few positions. The vast majority of such position pairs are in contact in representative structures. The identification of strongly coevolving position pairs can be used to impose significant structural limitations and should be an important additional constraint for ab initio protein folding.

Availability: Alignments and program files can be found in the Supplementary Information.

Contact:  ggloor@uwo.ca

Supplementary information: Supplementary data are available at Bioinformatics online.
Harmless nectar source or deadly trap:Nepenthespitchers are activated by rain, condensation and nectar
Authors: Bauer Ulrike , Bohn Holger F , Federle Walter
Published: December 2007

The leaves ofNepenthespitcher plants are specialized pitfall traps which capture and digest arthropod prey. In many species, insects become trapped by ‘aquaplaning’ on the wet pitcher rim (peristome). Here we investigate the ecological implications of this capture mechanism inNepenthes rafflesianavar.typica. We combine meteorological data and continuous field measurements of peristome wetness using electrical conductance with experimental assessments of the pitchers' capture efficiency. Our results demonstrate that pitchers can be highly effective traps with capture rates as high as 80% but completely ineffective at other times. These dramatic changes are due to the wetting condition of the peristome. Variation of peristome wetness and capture efficiency was perfectly synchronous, and caused by rain, condensation and nectar secreted from peristome nectaries. The presence of nectar on the peristome increased surface wetness mainly indirectly by its hygroscopic properties. Experiments confirmed that pitchers with removed peristome nectaries remained generally drier and captured prey less efficiently than untreated controls. This role of nectar in prey capture represents a novel function of plant nectar. We propose that the intermittent and unpredictable activation ofNepenthespitcher traps facilitates ant recruitment and constitutes a strategy to maximize prey capture.
Atg7-dependent autophagy promotes neuronal health, stress tolerance, and longevity but is dispensable for metamorphosis in Drosophila
Authors: Juhász Gábor , Érdi Balázs , Sass Miklós , Neufeld Thomas P.
Published: December 2007

Autophagy, a cellular process of cytoplasmic degradation and recycling, is induced in Drosophila larval tissues during metamorphosis, potentially contributing to their destruction or reorganization. Unexpectedly, we find that flies lacking the core autophagy regulator Atg7 are viable, despite severe defects in autophagy. Although metamorphic cell death is perturbed in Atg7 mutants, the larval–adult midgut transition proceeds normally, with extended pupal development compensating for reduced autophagy. Atg7−/− adults are short-lived, hypersensitive to nutrient and oxidative stress, and accumulate ubiquitin-positive aggregates in degenerating neurons. Thus, normal levels of autophagy are crucial for stress survival and continuous cellular renewal, but not metamorphosis.
Nickel-Intensified ABC-HRP Antibody Staining of Imaginal Discs in Drosophila
Authors: Blair Seth S.
Published: December 2007

INTRODUCTION

This protocol describes a sensitive method for labeling Drosophila imaginal disc tissues with a single antiserum. Labeling is visualized using a nickel-intensified avidin/biotinylated enzyme complex-horseradish peroxidase (ABC-HRP) staining procedure. This method is more sensitive, and has a lower signal-to-noise ratio, than fluorescent labeling. Although these methods are useful for visualizing genetic mosaic clones in wandering larval stage imaginal discs and pupal tissues from Drosophila, the immunohistological techniques are generally applicable to the description of protein expression.
Methylation Interference Assay
Authors: Carey Michael , Smale Stephen T.
Published: December 2007

INTRODUCTION

Methylation interference (and methylation protection) is the major technique for studying the interaction of proteins with major-groove guanines, although it also detects adenines in the minor groove and cytosines in single-stranded DNA. It is one of the highest-resolution methods for measuring the bases involved in sequence-specific recognition by proteins. A 32P-end-labeled DNA containing a recognition site is methylated (on average once per DNA molecule) by dimethyl sulfate (DMS) and then protein is allowed to bind. Certain methylation modifications prevent the protein from binding because they are at positions where the protein comes into close proximity with the DNA. Most modifications, however, have no effect on binding. The bound and unbound DNA molecules are separated using the electrophoretic mobility shift assay (or filter binding, immunoprecipitation, or any other suitable technique). The unbound fraction will be enriched in DNA molecules containing modifications at positions that interfere with protein binding. In contrast, the bound fraction will contain modifications that do not interfere with binding of the protein. Methylation weakens the nucleotide and makes it susceptible to piperidine-induced depurination. This leads, in turn, to scission of the DNA backbone. The cleaved fragments are fractionated on a sequencing gel alongside chemical sequencing ladders to identify the affected positions.
Resistant invaders can convey benefits to native species
Authors: Kopp Kirstin , Jokela Jukka
Published: December 2007

Introduced species are recognized as a major threat to native species. One factor that facilitates their spread is that they are often resistant to natural enemies of their native competitor. Negative effects of the invaders are often documented, but invaders may also convey benefits to the natives if they interfere with the native host‐parasite interactions. If invaders act as resistant targets for the native parasites, they may reduce the density of the infectious transmission stages (‘dilution effect’) and decrease the risk of infection for the natives. We tested this hypothesis by exposing coexisting native and introduced freshwater snails to infectious stages of a native parasite. The native hosts showed a significantly reduced infection rate when exposed together with the resistant invader. A significant amount of the parasite transmission stages was wasted on the resistant invader leading to lower risk of infection for the natives. Our results show that invaders may convey benefits to the native competitors by perturbing the native host‐parasite interaction and support the idea that the ‘dilution effect’ could be important for invaded communities.
Contrasting relationships between precipitation and species richness in space and time
Authors: Adler Peter B. , Levine Jonathan M.
Published: December 2007

Future changes in precipitation regimes are likely to impact species richness in water‐limited plant communities. Regional, spatial relationships between precipitation and richness could offer information about how altered rainfall will impact local communities, assuming that processes driving the regional relationship are also dominant at fine spatial and short temporal scales. To test this assumption, we compared spatial and temporal relationships between precipitation and both species richness and species turnover in central North American grasslands. Across a broad geographic gradient, mean plant species richness in 1‐m2 plots increased significantly with mean annual precipitation. In contrast, over a 36‐yr period at one mixed‐grass prairie in the center of the regional gradient, single‐year precipitation and richness were poorly correlated, and consecutive wet years had little effect on richness. Instead, richness increased most in wet years that followed dry years. Geographically dispersed sites receiving different levels of mean annual precipitation displayed strong differences in species composition, whereas temporal variation in precipitation at one site was not related to compositional dissimilarity, indicating that species turnover plays a key role in generating the regional relationship. Analyses of individual species’ presence‐absence suggest that the lagged temporal responses reflect environmental germination cues more than resource competition. These complex cues may dampen the initial impact of altered precipitation on diversity, but over the long term, turnover in species composition should lead to changes in richness, as in the regional, spatial relationship. How quickly this long‐term response develops may depend on the colonization rates of species better adapted to the altered rainfall regime.
Increasing intraspecific diversity increases predictability in population survival in the face of perturbations
Authors: Gamfeldt Lars , Källström Björn
Published: December 2007

It has been proposed that biodiversity can be important for ecosystem functioning and act as an insurance against perturbations and environmental fluctuations. To date, theoretical work supports this idea but direct experimental evidence is still to some extent ambiguous and debated. The main reason for this debate – and the lack of strong empirical support – is due to unavoidable experimentally and statistically inherent variance reduction effects. Here we present the results of an experimental study that circumvents earlier hidden treatments. By random draw without replacement, we collected 180 full‐sibling batches of an amphipod from a large pool of possible parents. Assembled amphipod populations with diversity levels ranging from one to ten were exposed to either a single perturbation (nutrient enrichment) or two combined perturbations (nutrient enrichment and desiccation). The results show that the variance in the number of surviving individuals decreased with increasing diversity in the combined perturbations treatment. Predictability in population survival thus seemed to be higher in more diverse assemblages. Our results, together with a simple model suggest that variance‐decreasing effects can be due to actual real world statistical sampling effects of increasing diversity.
Biomechanical warfare in ecology; negative interactions between species by habitat modification
Authors: Van Wesenbeeck B. K. , Van De Koppel J. , Herman P. M. J. , Bakker J. P. , Bouma T. J.
Published: December 2007

Since the introduction of the term ecosystem engineering by Jones et al. many studies have focused on positive, facilitative interactions caused by ecosystem engineering. Much less emphasis has been placed on the role of ecosystem engineering in causing negative interactions between species. Here, we report on negative interactions between two well known ecosystem engineers occurring at the interface of salt marsh and intertidal flat (i.e. common cordgrass Spartina anglica and lugworms Arenicolamarina), via modification of their joint habitat. A field survey indicated that, although both species share a common habitat, they rarely co‐occur on small spatial scales (<1 m). Experiments in the field and in mesocosms reveal that establishment of small Spartina plants is inhibited in Arenicola‐dominated patches because of low sediment stability induced by the lugworms. In turn, Arenicola establishment in Spartina‐dominated patches is limited by high silt content, compactness and dense rooting of the sediment caused by Spartina presence. Our results show that negative interactions by modification of the environment can result in rapid mutual exclusion, particularly if adverse effects of habitat modification are strong and if both species exhibit positive feedbacks. This illustrates the potential for negative interactions via the environment to affect community composition.