bluuebunny/crossref_metadata_2025 huggingface dataset:
Language Acquisition and Language Change: Inter‐relationships
Authors: Lightfoot David , Westergaard Marit
Published: September 2007

Children acquire a mature language system and sometimes this system differs from that of their parents. This is a significant part of language change and understanding acquisition is key to understanding this kind of change in people's internal grammars. We outline an approach to language acquisition that is based on children finding cues and microcues expressed in the input they are exposed to. This enables us to understand historical change in grammars: change in external language sometimes triggers a new internal grammar as cues come to be expressed differently. We bring together work on language variation, acquisition, and change, show how these three areas are mutually dependent, and how empirical work in one area may enrich understanding more generally, opening the way to new kinds of empirical work.
Negation in Natural Language: On the Form and Meaning of Negative Elements
Authors: Zeijlstra Hedde
Published: September 2007

A universal property of natural language is that every language is able to express negation. Every language has some device at its disposal to reverse the truth value of a certain sentence. However, languages may differ to quite a large extent as to how they express this negation. Not only do languages vary with respect to the position of negative elements, also the form of negative elements and the interpretation of sentences that consist of multiple negative elements are subject to broad cross‐linguistic variation. The study to the behaviour of sentential negation has therefore strongly been guided by the question as to what determines the possible ways that sentential negation can manifest itself. A conclusion of the article will be that the behaviour of negation in natural language strongly deviates from what intuitively might be expected.
Contemporary Political Communications: Audiences, Politicians and the Media in International Research
Authors: Young Sally , Bourne Saskia , Younane Stephanie
Published: September 2007

Research into political communication has grown rapidly in the past three decades, shifting from specific, quantitative and utilitarian studies to include a broad variety of research questions, methods and theoretical frameworks. Interdisciplinary work in political communication takes audiences, political actors (such as governments and politicians), and media content and media institutions as central foci. Research has traditionally focused on election campaign‐specific studies within national contexts. Emerging research, however, is now addressing broader questions about media texts and organisations and also about representations and power. This research is working to trace technological changes and developments in an era of globalised media and political communication and developing new, complex conceptions of audience agency and reception.
Globalization of Culture and the Arts
Authors: Adams Laura L.
Published: September 2007

This article examines the state of the field in the sociological literature on the globalization of culture and focuses on key empirical works in the globalization of the arts. The first part of the article presents the main trends in theorizing about the globalization of culture in its broadest terms, that is, the large‐scale changes in worldviews that both facilitate and are made possible by globalization such as modernization, universalism, consumerism, and McDonaldization. The second part of the article examines empirical work on television, music, and the performing arts in light of theorizing about globalization and commodification, audience reception, localization and glocalization, the role of the state, imperialism, global cultural fields, and global norms. In terms of theory, the article explores the tension between globalization's homogenizing and diversifying tendencies. The review of the empirical literature includes research conducted in Cuba, Israel, Italy, Japan, Russia, Singapore, the USA, and Uzbekistan.
Working‐Class Studies: Ongoing and New Directions
Authors: Roberts Ian
Published: September 2007

This paper gives an account of working‐class studies as it has developed in the USA and UK. It includes a comparative assessment of ways in which the working‐class and class analysis appear within academe. This argues that the different role played by social classes in the post‐war settlement and its subsequent breakdown can account for divergent fortunes of class analysis in response to similar developments. The paper unpacks some of the opportunities and threats to further development of working‐class studies in the UK. It is argued that the field needs to be developed in a way that is reflexively self‐critical and avoids reproducing middle‐class experience as universal. However, it notes the challenge of opening up space for the working class within the academy, particularly given the problem of the institutional embodiment of class together with the rigid framework of higher education in the UK.
Racial Residential Segregation and Crime
Authors: Akins Scott
Published: September 2007

Racial residential segregation is a pervasive and persistent feature of life in urban America. The consequences of segregation are numerous and are generally deleterious for minority populations. One consequence of segregation is inflated rates of crime in segregated areas. However, the study of segregation and crime is limited to a handful of studies and many questions remain unanswered. These include: (i) Does the criminogenic effect of segregation remain when research employs a unit of analysis other than cities (e.g., neighborhoods, regions)? (ii) What is the primary theoretical mechanism by which racial segregation produces crime? (iii) What types of mediating processes can attenuate the criminogenic effect of segregation? The current article will summarize the interdisciplinary literature on segregation and crime and discuss avenues for future research.
Crossing Boundaries: Legality and the Power of the State in Unauthorized Migration
Authors: Yamamoto Ryoko
Published: September 2007

Unauthorized migrants, often referred to as ‘illegal aliens’ or ‘undocumented immigrants’, are a burning political issue in many countries. This paper examines the complexities of unauthorized migration and addresses competing viewpoints on the subject as it relates to the power of the state. Despite the popular image of unauthorized migration as secret border crossing, migrants become ‘illegal’ in various ways, and the boundary between ‘legal’ and ‘illegal’ is more fluid than it may appear to be. Unauthorized migration is conventionally understood as evidence of the limited power of the state over immigration. This view, however, too narrowly focuses on the power of the state over entries of migrants. If we broaden our perspective and examine its power over migrants’lives and the way in which they are integrated into society, unauthorized migration in fact reveals the strong power of the state, which has a capacity to deprive migrants of their rights.
Methodological Dilemmas and Opportunities in Interviewing Organizational Elites
Authors: Delaney Kevin J.
Published: September 2007

This article discusses the challenges and opportunities encountered in interviewing organizational elites. Drawing on a wide range of experiences in elite interviewing, I offer suggestions for gaining access to elites, controlling the interview, obtaining the highest‐quality interview data, and writing effectively about those data. I also discuss the ‘dilemma of seduction’ that can occur in elite interviewing and suggests ways to both present and critique the worldview of elites when writing about qualitative interviews.
Functional Heartburn and Non-Erosive Reflux Disease
Authors: Savarino Vincenzo , Savarino Edoardo , Parodi Andrea , Dulbecco Pietro
Published: September 2007

Gastroesophageal reflux disease (GERD) is a common disorder in Western countries. For many years our attention has been focused on patients with erosive esophagitis, but in recent times we have realized that endoscopy-negative reflux disease is the most common presentation of this illness, affecting up to 70% of these individuals. Patients with the non-erosive form (NERD) are a heterogeneous group including various subpopulations with different mechanisms for their main symptom of heartburn: reflux of acidic and non-acidic gastric contents, mucosal hypersensitivity, intraesophageal distension by gas, intraduodenal infusion of fat, muscle contractions and psychological abnormalities. As to esophageal acid exposure, patients with NERD can be subdivided into those with abnormal and normal pH testing. The latter group includes patients with a positive correlation between symptoms and reflux events, in whom heartburn can be controlled by proton pump inhibitor (PPI) therapy. According to the recent Rome III criteria, they are still in the realm of GERD. An additional group is called functional heartburn, because this typical symptom is associated neither with an abnormal pH test nor with a positive symptom index. Their response to PPIs is very disappointing. Therefore, there is an increasing consensus on the fact that they do not have GERD and should be treated with drugs other than PPIs.
Therapy of Gastroesophageal Reflux: Evidence-Based Approach to Antireflux Surgery
Authors: Lundell Lars
Published: September 2007

Background: Due to the chronic, relapsing nature of gastroesophageal reflux disease, lifelong therapeutic options have to be considered and recommended in many patients. Accordingly, surgical repair has to be evaluated based on modern, evidence-based methodologies. Methods: A careful review has been carried out of the relevant surgical literature also including trials incorporating direct comparisons between medical and surgical therapies. The outcome of such a survey has been structured according to the grading of evidence from highest grade I to the lowest III. Results: Grade I evidence exists to show that antireflux surgery is more effective than proton pump inhibition in the control of reflux-related symptoms. Side effects are burdening surgical repair, many of which do not decrease over time. Data are not consistent to show any benefit of surgery whenever health economic outcomes are required. Minor differences are in favor of laparoscopic operations and it does matter who is doing the operation and how the repair is completed. Better data are requested to assess the true long-term efficacy (>10 years) of corresponding operations. Conclusion: Antireflux surgery is an effective and durable therapeutic modality in the long-term management of gastroesophageal reflux disease.
Screening for and Surveillance of Barrett’s Esophagus Is Clinically Indicated
Authors: Cengia G. , Missale G. , Minelli L. , Villanacci V. , Rossi E. , Cestari R.
Published: September 2007

Barrett’s esophagus (BE) is a complication of chronic gastroesophageal reflux disease (GERD) and is the precursor of esophageal adenocarcinoma (EA), through a progression from intestinal metaplasia (IM), through high-grade dysplasia (HGD). Although the progression from BE to EA seems to be infrequent (0.5% per year), endoscopic and bioptic surveillance would play a significant role in the evaluation of HGD and the detection of EA in early, curable stage, improving survival rates after treatments. The severity and the duration of GERD could be helpful in the assessment of the risk for BE and to enroll these subjects into screening protocols to detect any dysplastic or neoplastic change. The benefits of screening-surveillance programs could be furthermore enhanced by an improvement in diagnostic methods, such as high-resolution endoscopic techniques and the use of biomarkers for the histological examination seems to play a primary role in the cancer risk stratification; in such way, endoscopic resection techniques (mucosal resection and submucosal dissection) can be considered as a helpful method to stage dysplastic changes in BE.
Is Screening for and Surveillance of Atrophic Gastritis Advisable?
Authors: Nardone Gerardo , Rocco Alba , Compare Debora , De Colibus Patrizia , Autiero Giovanni , Pica Loredana , De Nucci Germana , Gasbarrini Giovanni
Published: September 2007

Gastric cancer remains a leading cause of cancer-related deaths in many parts of the world. At present, prevention seems to be the most effective means to reduce its the incidence and mortality rate. Gastric atrophy is considered the first relevant step in the histogenesis of gastric adenocarcinoma. However, whether screening for and surveillance of atrophic gastritis is advisable is debated. The prevalence and pattern of chronic atrophic gastritis varies greatly from country to country, being higher and mainly diffuse pangastritis or localized in those countries with a high gastric cancer incidence. The only method available to detect gastric atrophy is histopathological examination of endoscopic specimens, but there is no consensus about diagnosis. Serum gastric secretion may be a marker of gastric atrophy, although it has high specificity but low sensitivity. Gastric atrophy is mainly related to chronic Helicobacter pylori (H. pylori) infection. Thus, the only effective strategy for gastric cancer prevention is eradication of H. pylori infection to arrest atrophy progression in selected populations. In conclusion, there is insufficient evidence to suggest screening for and surveillance of atrophic gastritis in the general population; however, this strategy should be applied in countries with a high incidence of gastric cancer.
Should We Screen for Helicobacter pylori to Prevent Gastric Cancer?
Authors: Leja M. , Dumitrascu D.L.
Published: September 2007

Although the strategy for Helicobacter pylori infection management is well defined and quite well followed in a number of situations, including peptic ulcer disease, the issue of H. pylori screening and eradication in the general population still remains. The following debate attempts to find the answer of whether or not H. pylori screening should be performed in the asymptomatic population for preventing gastric cancer. As yet, there is no final evidence-based consensus about the need to screen for H. pylori in order to decrease the incidence of gastric cancer.
Molecular Epidemiology of Gastric Cancer
Authors: Starzyńska Teresa
Published: September 2007

Molecular epidemiology refers to the incorporation of molecular techniques in epidemiological studies. There are different biomarkers in cancer research used for molecular epidemiology including markers of exposure, markers of dose, susceptibility, treatment response, prognosis, altered structure/function and cancer type. Selected markers, especially those of exposure and susceptibility, are described in an example of gastric cancer. Clinical significance of molecular epidemiology is discussed.
Almost All Irritable Bowel Syndromes Are Post-Infectious and Respond to Probiotics: Controversial Issues
Authors: Barbara Giovanni , Stanghellini Vincenzo , Cremon Cesare , De Giorgio Roberto , Corinaldesi Roberto
Published: September 2007

Acute infectious gastroenteritis is the strongest known risk factor for the development of irritable bowel syndrome (IBS), one of the most common functional gastrointestinal disorders. However, knowledge about the incidence and prevalence of post-infectious IBS (PI-IBS) in the general population is still limited. Some of the published epidemiological studies on PI-IBS lack an appropriate control population, and were limited by a short follow-up symptom assessment post-infection. A number of risk factors have been associated with the development of PI-IBS, including the virulence of the pathogen, younger age, female sex, the long duration of the initial illness and the presence of psychological disturbances. However, much work has to be done to establish whether multifactorial mechanisms actually concur to the pathophysiology of PI-IBS. The discovery that an infective episode may trigger the development of IBS has not substantially changed the clinical management of this subset of patients compared to the classical (non-infective) form of IBS. Probiotics have been claimed to be of some benefit in IBS, but the majority of studies have been performed in non-specific IBS rather than in PI-IBS and a number of issues still remain to be elucidated.
Quality of Life in Uncomplicated Symptomatic Diverticular Disease: Is It Another Good Reason for Treatment?
Authors: Comparato Giuseppe , Fanigliulo Libera , Aragona Giovanni , Cavestro Giulia M. , Cavallaro Lucas G. , Leandro Gioacchino , Pilotto Alberto , Nervi Giorgio , Soliani Paolo , Sianesi Mario , Franzé Angelo , Di Mario Francesco
Published: September 2007

Background: Quality of life (QoL) is becoming a major issue in the evaluation of any therapeutic intervention. Aims: To assess the QoL in patients with uncomplicated symptomatic diverticular disease (DD) and to elucidate the influence of two different treatments either on symptoms or QoL. Materials and Methods: 58 outpatients affected by uncomplicated symptomatic DD, admitted in our Gastroenterological Unit from October 2003 to March 2004, were enrolled. Patients were randomly assigned to two different treatments consisting of rifaximin or mesalazine for 10 days every month for a period of 6 months. QoL was evaluated by means of an SF-36 questionnaire and clinical evaluation was registered by means of a global symptomatic score (GSS) at baseline and after 6 months. Results: At baseline, lower values in all SF-36 domains were confirmed in patients with DD. Both rifaximin and mesalazine groups showed a significant reduction of their mean GSS (p < 0.01 and p < 0.001, respectively) and improvement of SF-36 mean scores after therapy, even though treatment with mesalazine showed better results. Conclusions: DD has a negative impact on QoL. Cyclic treatment with poorly absorbable antibiotics or anti-inflammatory drugs relieves symptoms and improves QoL.
Medical Therapy for Crohn’s Disease: Top-Down or Step-Up?
Authors: Baert Filip , Caprilli Renzo , Angelucci Erika
Published: September 2007

The emergency of effective biological therapy in the treatment of Crohn’s disease (CD) has led to a clinical debate about ‘step-up versus top-down strategy’. Step-up refers to the classic therapeutic approach, namely progressive intensification of treatment as disease severity increases. Top-down refers to the early introduction, in all CD patients, of intensive therapies, including biological agents and immunosuppressive drugs, with the aim of avoiding complications and improving quality of life, starting from the assumption that these drugs may interfere with the natural history of the disease. Very recently the Belgian IBD research group together with the Gut Club of North Holland designed ‘the Step Up versus Top Down Trial’. Combination of infliximab with immunosuppressives at onset was better than the current standard approach in terms of both induction and maintenance of remission. However, several observations still limit the use of infliximab as first-line treatment in adult CD patients. In particular, the epidemiological observation that over 50% of CD patients have a mild disease over time and will never require aggressive therapies is against the indiscriminate use of top-down strategy. Lack of markers able to identify high-risk patients, discussions about long-term safety and the high costs of infliximab are further factors supporting a more careful approach to the management of CD.
Hepatitis C Virus with Normal Transaminase Levels
Authors: Puoti Claudio
Published: September 2007

Approximately 30% of patients with chronic HCV infection show persistently normal alanine aminotransferase (PNALT) levels. The majority of these patients have some degree of histological liver damage. Controversies still exist regarding the definition of ‘persistent’ alanine aminotransferase (ALT) normality, and the natural history and optimal management of chronic hepatitis C with normal ALT. Although patients with HCV infection and normal ALT have been historically excluded from antiviral treatment, with the advent of the new treatment with PEG-interferon plus ribavirin, it has been suggested that the issue of whether or not to treat subjects with PNALT should be re-evaluated, and that antiviral treatment should be useful at least in selected subsets of patients.
Risk Factors of Chronic Pancreatitis
Authors: Uomo Generoso , Manes Gianpiero
Published: September 2007

Chronic pancreatitis (CP) still remains a challenging clinical problem with many controversial issues regarding pathogenesis, outcome, and treatment. The disease comprises a spectrum of disorders that culminate as a final step in the destruction of the pancreas. Complex interaction does exist between genetic, environmental and immunologic factors leading to development of the disease. Multiple risk factors interact in a multiple-step model; the pancreatic injury may occur through different mechanisms with transition between an acute pancreatitis condition to recurrent pancreatitis and, finally, to CP. Most patients have multiple risk factors and the overall risk is a product of all risk factors in additive or multiplicative fashion. Susceptibility to develop CP in alcoholics depends on the expression of single gene mutation or is derived from complex genetic polymorphism; in addition, smoking habit can influence the risk of pancreatic calcifications and severity in alcoholic and idiopathic CP. Alteration of the immune response induced by gene mutations and/or environmental factors represents the main determinant of pancreatic fibrosis, the end-stage histologic feature from all CP etiologies.
Pancreatic Cancer Is ‘Always Non-Resectable’
Authors: Mönkemüller Klaus , Fry Lucia C. , Malfertheiner Peter
Published: September 2007

Pancreatic cancer is characterized by its very aggressive biological behavior which makes it a rapidly disseminating and deadly tumor. Due to their initial ‘silent’ behavior, pancreatic cancers are generally diagnosed too late and at that point surgical or medical interventions are futile. The outcome of pancreatic cancer has not improved over the last decades. It is evident that only very few pancreatic cancers are potentially resectable and curable, but many times even these small cancers have poor prognostic factors. Furthermore, upon surgery many of the patients considered preoperatively to have resectable tumors are found to have non-resectable disease. The problem of pancreatic cancer is further compounded by the fact that most tumors are diagnosed in elderly, frail or chronically ill patients, which makes them poor surgical candidates, and only half or fewer of these patients can undergo surgery. The stress of surgery is poorly tolerated by many patients who either die, develop complications or are then unable to receive adjuvant chemotherapy. The bottom line is that pancreatic cancer is a very aggressive tumor. Currently, most cancers are treated by non-surgical methods, and the very few patients with tumors which are potentially resectable should be operated on in specialized, high-volume pancreatic centers.
Structural and Functional Diversity of Microcins, Gene-Encoded Antibacterial Peptides from Enterobacteria
Authors: Duquesne Sophie , Petit Vanessa , Peduzzi Jean , Rebuffat Sylvie
Published: September 2007

Microcins are a peculiar class of gene-encoded low-molecular-mass antibacterial peptides secreted by enterobacteria. They contribute to the regulation of microbial competitions within the intestinal microbiota. The genetic systems involved in microcin biosynthesis share a conserved organization. Similar to bacteriocins of Gram-positive bacteria, microcins exert potent antibacterial activity directed against phylogenetically-related bacterial strains, with minimal inhibitory concentrations in the nanomolar range. In contrast to bacteriocins, they display a great structural diversity among the few representatives well characterized until now, that makes difficult the description of microcin subclasses. This review focuses on three microcins, MccE492m that carries a C-terminal posttranslational modification containing a catechol-type siderophore, MccJ25, a cyclic peptide with a unique ‘lasso-type’ structure and MccC7 or C51, with a common N-formylated heptapeptide-nucleotide structure. We show these microcins exhibit ‘Trojan horse’ mechanisms of antibacterial activity: either (i) the microcin structure is a mime of an essential element, permitting its recognition by outer membrane receptors used for vital functions in bacteria and further translocation into the periplasmic space, or (ii) it is secreted as a harmless molecule and further processed in susceptible bacteria to form the toxic entity. When inside target bacteria, microcins bind essential enzymes or interact with the inner membrane to form a bacterial killing structure.
Lantibiotic Engineering: Molecular Characterization and Exploitation of Lantibiotic-Synthesizing Enzymes for Peptide Engineering
Authors: Nagao Jun-ichi , Aso Yuji , Shioya Kouki , Nakayama Jiro , Sonomoto Kenji
Published: September 2007

Lanthionine-containing peptide antibiotics called lantibiotics are produced by a large number of Gram-positive bacteria. Nukacin ISK-1 produced by Staphylococcus warneri ISK-1 is type-A(II) lantibiotic. Ribosomally synthesized nukacin ISK-1 prepeptide (NukA) consists of an N-terminal leader peptide followed by a C-terminal propeptide moiety that undergoes several post-translational modification events including unusual amino acid formation by the modification enzyme NukM, cleavage of leader peptide and export by the dual functional ABC transporter NukT, finally yielding a biologically active peptide. Unusual amino acids in lantibiotics contribute to biological activity and also structural stability against proteases. Thus, lantibiotic-synthesizing enzymes have a high potentiality for peptide engineering by introduction of unusual amino acids into desired peptides with altering biological and physicochemical properties, e.g., activity and stability, termed lantibiotic engineering. We report the establishment of a heterologous expression of nukacin ISK-1 biosynthetic gene cluster by the nisin-controlled expression system and discuss our recent progress in understanding of the biosynthetic enzymes for nukacin ISK-1 such as localization, molecular interaction in biophysical and biochemical aspects. Substrate specificity of the lantibiotic-synthesizing enzymes was evaluated by complementation of the biosynthetic enzymes (LctM and LctT) of closely related lantibiotic lacticin 481 for nukacin ISK-1 biosynthesis. We further explored a rapid and powerful tool for introduction of unusual amino acids by co-expression of hexa-histidine-tagged NukA and NukM in Escherichia coli.
The Two-Peptide Class II Bacteriocins: Structure, Production, and Mode of Action
Authors: Oppegård Camilla , Rogne Per , Emanuelsen Linda , Kristiansen Per Eugen , Fimland Gunnar , Nissen-Meyer Jon
Published: September 2007

The two-peptide class II bacteriocins consist of two different unmodified peptides, both of which must be present in about equal amounts in order for these bacteriocins to exert optimal antimicrobial activity. These bacteriocins render the membrane of target cells permeable to various small molecules. The genes encoding the two peptides of two-peptide bacteriocins are adjacent to each other in the same operon and they are near the genes encoding (i) the immunity protein that protects the bacteriocin-producing bacteria from being killed by their own bacteriocin, (ii) a dedicated ABC transporter that transports the bacteriocin out of the bacteriocin-producing bacteria, and (iii) an accessory protein whose specific role is not known, but which also appears to be required for secretion of the bacteriocin. The production of some two-peptide bacteriocins is transcriptionally regulated through a three-component regulatory system that consists of a membrane-interacting peptide pheromone, a membrane-associated histidine protein kinase, and response regulators. Structure analysis of three two-peptide bacteriocins (plantaricin E/F, plantaricin J/K, and lactococcin G) by CD (and in part by NMR) spectroscopy reveal that these bacteriocins contain long amphiphilic α-helical stretches and that the two complementary peptides interact and structure each other when exposed to membrane-like entities. Lactococcin G shares about 55% sequence identity with enterocin 1071, but these two bacteriocins nevertheless kill different types of bacteria. The target-cell specificity of lactococcin G-enterocin 1071 hybrid bacteriocins that have been constructed by site-directed mutagenesis suggests that the β-peptide is important for determining the target-cell specificity.
Amphiphilic Dendrimeric Peptides as Model Non-Sequential Pharmacophores with Antimicrobial Properties
Authors: Janiszewska Jolanta , Urbanczyk-Lipkowska Zofia
Published: September 2007

A concept of application of dendrimer chemistry for construction of ‘non-sequential pharmacophore’, mimicking active conformation of linear antimicrobial peptides, is introduced. It resulted in the synthesis of a family of low- molecular-weight basic peptide dendrimers with antimicrobial properties against Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative) and Candida albicans.
Bacteriocins from Lactic Acid Bacteria: Production, Purification, and Food Applications
Authors: De Vuyst Luc , Leroy Frédéric
Published: September 2007

In fermented foods, lactic acid bacteria (LAB) display numerous antimicrobial activities. This is mainly due to the production of organic acids, but also of other compounds, such as bacteriocins and antifungal peptides. Several bacteriocins with industrial potential have been purified and characterized. The kinetics of bacteriocin production by LAB in relation to process factors have been studied in detail through mathematical modeling and positive predictive microbiology. Application of bacteriocin-producing starter cultures in sourdough (to increase competitiveness), in fermented sausage (anti-listerial effect), and in cheese (anti-listerial and anti-clostridial effects), have been studied during in vitro laboratory fermentations as well as on pilot-scale level. The highly promising results of these studies underline the important role that functional, bacteriocinogenic LAB strains may play in the food industry as starter cultures, co-cultures, or bioprotective cultures, to improve food quality and safety. In addition, antimicrobial production by probiotic LAB might play a role during in vivo interactions occurring in the human gastrointestinal tract, hence contributing to gut health.
The Antifungal Activity of RsAFP2, a Plant Defensin from Raphanus sativus, Involves the Induction of Reactive Oxygen Species in Candida albicans
Authors: Aerts An M. , François Isabelle E.J.A. , Meert Els M.K. , Li Qiu-Tian , Cammue Bruno P.A. , Thevissen Karin
Published: September 2007

RsAFP2 (Raphanus sativus antifungal peptide 2), an antifungal plant defensin isolated from seed of R. sativus, interacts with glucosylceramides (GlcCer) in membranes of susceptible yeast and fungi and induces membrane permeabilization and fungal cell death. However, using carboxyfluorescein-containing small unilamellar vesicles containing purified GlcCer, we could not observe permeabilization as a consequence of insertion of RsAFP2 in such vesicles. Therefore, we focused on a putative RsAFP2-induced signaling cascade downstream of RsAFP2-binding to GlcCer in fungal membranes. We show that RsAFP2 induces reactive oxygen species (ROS) in Candida albicans wild type in a dose-dependent manner, but not at all in an RsAFP2-resistant ΔgcsC. albicans mutant that lacks the RsAFP2-binding site in its membranes. These findings indicate that upstream binding of RsAFP2 to GlcCer is needed for ROS production leading to yeast cell death. Moreover, the antioxidant ascorbic acid blocks RsAFP2-induced ROS generation, as well as RsAFP2 antifungal activity. These data point to the presence of an intracellular plant defensin-induced signaling cascade, which involves ROS generation and leads to fungal cell growth arrest.
Nisin Biosynthesis in vitro
Authors: Cheng Fang , Takala Timo M. , Saris Per E.J.
Published: September 2007

The lantibiotic nisin is produced by Lactococcus lactis. In the biosynthesis of nisin, the enzyme NisB dehydrates nisin precursor, and the enzyme NisC is needed for lanthionine formation. In this study, the nisA gene encoding the nisin precursor, and the genes nisB and nisC of the lantibiotic modification machinery were expressed together in vitro by the Rapid Translation System (RTS). Analysis of the RTS mixture showed that fully modified nisin precursor was formed. By treating the mixture with trypsin, active nisin was obtained. However, no nisin could be detected in the mixture without zinc supplementation, explained by the fact that NisC requires zinc for its function. The results revealed that the modification of nisin precursor, which is supposed to occur at the inner side of the membrane by an enzyme complex consisting of NisB, NisC, and the transporter NisT, can take place without membrane association and without NisT. This in vitro production system for nisin opens up the possibility to produce nisin variants that cannot be producedin vivo. Moreover, the system is a promising tool for utilizing the NisB and NisC enzymes for incorporation of thioether rings into medical peptides and hormones for increased stability.
Antimicrobial Activity of Divercin RV41 Produced and Secreted by Lactococcus lactis
Authors: Bermúdez-Humarán Luis G. , Rihakova Jitka , Langella Philippe , Demnerova Katerina , Nazef Lila , Prévost Hervé , Drider Djamel
Published: September 2007

Divercin V41 is a class IIa bacteriocin produced by Carnobacterium divergens V41 with a strong anti-Listeria activity. We have previously produced a recombinant form of divercin V41 (DvnRV41) in Escherichia coli strain Origami, by cloning a synthetic gene that codes for a mature divercin RV41 peptide. In this work we describe the inducible expression and secretion of DvnRV41 in the food-grade lactic acid bacterium, Lactococcus lactis. The production of DvnRV41 by recombinant L. lactis was confirmed and quantified by Western blot and ELISA assays. In addition, anti-Listeria activity of DvnRV41 was determined using an agar diffusion test. Although the levels of DvnRV41 produced by recombinant L. lactis were similar to those produced by the natural host, C. divergens V41, the specific activities were lower. In conclusion, our data show that the bacteriocin DvnRV41 is produced and secreted in an active form by L. lactis and that this approach may have important applications in the preservation of foods.
Caries Prevalence Four Years after the End of a Randomised Controlled Trial
Authors: Pine C.M. , Curnow M.M.T. , Burnside G. , Nicholson J.A. , Roberts A.J.
Published: September 2007

This study measured dental caries in children after cessation of a 30-month randomised clinical trial in which the intervention group received supervised toothbrushing once a day at school with 1,000 ppm fluoride toothpaste and a home support package encouraging twice-daily toothbrushing. The non-intervention group did not brush at school or receive the home support package. Children were aged 5 years at baseline and were examined every 6 months during the trial, then at 6, 18, 30 and 54 months after the end of the trial. Significantly less caries developed in first permanent molars of intervention children at the end of the trial. Of the 428 children who were examined at the end of the trial 329 (77%) were examined 54 months later when the children were aged 12 years on average. The intervention group still had less caries (D3FS caries increment 1.62) than the non-intervention children (D3FS caries increment 2.65, p < 0.05). Prolonged benefits have been found for intervention children principally in less caries in first permanent molars. Further follow-up at an age when the second molars and premolars have all erupted will help determine whether this benefit is due to a long-term behavioural change or a prolonged biological effect.
Primate Origins: Implications of a Cretaceous Ancestry
Authors: Martin Robert D. , Soligo Christophe , Tavaré Simon
Published: September 2007

It has long been accepted that the adaptive radiation of modern placental mammals, like that of modern birds, did not begin until after the Cretaceous/Tertiary (K/T) boundary 65 million years (Ma) ago, following the extinction of the dinosaurs. The first undoubted fossil relatives of modern primates appear in the record 55 Ma ago. However, in agreement with evidence from molecular phylogenies calibrated with dates from denser parts of the fossil record, a statistical analysis of the primate record allowing for major gaps now indicates a Cretaceous origin of euprimates 80–90 Ma ago. If this interpretation is correct, primates overlapped with dinosaurs by some 20 Ma prior to the K/T boundary, and the initial radiation of primates was probably truncated as part of the major extinction event that occurred at the end of the Cretaceous. Following a review of evidence for an early origin of primates, implications of this are discussed with respect to the likely ancestral condition for primates, including a southern continental area of origin and moderately large body size. The known early Tertiary primates are re-interpreted as northern continental offshoots of a ‘second wave’ of primate evolution.
Invading Europe: Did Climate or Geography Trigger Early Eocene Primate Dispersals?
Authors: Soligo Christophe
Published: September 2007

The Palaeocene-Eocene transition is characterized by a significant turnover of mammalian taxa in the fossil record of the northern continents, and primates are among the groups that make their first appearance at this time. One of the many questions that remain to be answered with regard to the earliest evolution of primates is the reason for their sudden and virtually simultaneous appearance in the fossil records of Asia, Europe and North America. The most obvious environmental correlate of the Palaeocene-Eocene transition is a sharp but relatively short-lived warming event leading up to the Palaeocene-Eocene thermal maximum (PETM) and evidenced in the stratigraphic record by a negative δ13C excursion. It remains unclear, however, whether or how this warming event may have influenced Palaeocene-Eocene faunal turnovers. This paper explores the hypothesis that environmental changes associated with the PETM facilitated an invasion of Western Europe by primates by comparing the ecological structure of local mammalian fauna immediately before and following the Palaeocene-Eocene transition. The results suggest that changes to the ecological profile of local mammalian fauna were relatively small and did not favour an invasion by primates, although a major uncertainty remains with respect to the availability of arboreal niches. At present it seems more likely that the invasion of western Europe by primates was due to the breakdown of one or more dispersal barriers close to the end of the Palaeocene.
Environmental Correlates of the Cercopithecoid Radiations
Authors: Elton Sarah
Published: September 2007

Modern Old World monkeys live in an array of habitats, an ability that was established early in their evolutionary history. The Old World monkey radiation is commonly correlated with the general trend of climatic cooling in the Neogene and the associated increase in open habitats. However, although they became more abundant and speciated extensively in the very late Miocene, Pliocene and Pleistocene, many of the major events in cercopithecoid evolution occurred before the onset of the late Miocene long cooling period. In the Plio-Pleistocene, regional environmental change and interspecific competition probably influenced the radiations of the Old World monkeys in Africa much more than did global climatic patterns. In southern Africa, the evolution of the monkey community is tied to Pleistocene increases in grassland and open habitats. In East Africa, the more diverse cercopithecid fauna reflects the presence of a wider variety of habitats, including forest, woodland and grassland.
Climatic Influences on the Evolution of Early Hom o?
Authors: Antón Susan C.
Published: September 2007

The nature of the human fossil record is less than ideal for the generation of precise correlations between environmental variables and patterns of evolution in specific lineages. Nonetheless, a critical look at what can and cannot be said from individual fossil morphology and the correlation of specific environmental proxies with specific hominin fossils may lead to a greater understanding of the degree of certainty with which we should embrace environmental hypotheses for the evolution ofHomo. Climate shifts have been implicated in both the origin of the genus and its dispersal from Africa. Here, I consider three areas in which a climatic influence has been posited to explain evolutionary shifts in the genusHomo: the origin and dispersal of the genus from Africa; geography, climate and body size in earlyHomo,and the influence of climate-induced sea level rise on morphological isolation inH. erectus. Each of the data sets is far from ideal, and interpretations of each of the data sets are fraught with issues of equifinality. Of the three hypotheses discussed, the clearest link is seen between latitudinal variation (and presumably temperature) and body size inH. erectus. Similarly, climate-induced sea level change seems a reasonable isolating mechanism to explain the pattern of cranial variation in later AsianH. erectus, but the distribution could also reflect incompletely sampled clinal variation. Alternatively, only equivocal support is found for the influence of climate on the differentiation ofH. erectusfromH. habilis(as proxied by body/brain size scaling), and therefore the dispersal of the genusHomocannot be as clearly linked to changes in body size and shape as it has been in the past. These preliminary data suggest that an emphasis on understanding local adaptation before looking at global (and specific) level change is critical to elucidating the importance of climatic factors on the evolution of the genusHomo.
The Evolution of Extinction Risk: Past and Present Anthropogenic Impacts on the Primate Communities of Madagascar
Authors: Godfrey Laurie R. , Irwin Mitchell T.
Published: September 2007

There are two possible approaches to understanding natural and human-induced changes in the primate communities of Madagascar. One is to begin with present-day and recent historic interactions and work backwards. A second is to begin with paleoecological records of Malagasy primate communities before and immediately following human arrival, and the associated evidence of human and nonhuman primate interactions, and work forwards. On the basis of biological and climatic studies, as well as historic and ethnohistoric records, we are beginning to understand the abiotic and biotic characteristics of Madagascar’s habitats, the lemurs’ ecological adaptations to these unique habitats, the extent of forest loss, fragmentation and hunting, and the differential vulnerability of extant lemur species to these pressures. On the basis of integrated paleoecological, archaeological and paleontological research, we have begun to construct a detailed chronology for late prehistoric Madagascar. We are beginning to understand the complex sequence of events that led to one of the most dramatic recent megafaunal extinction/extirpation events. Combining the perspectives of the past and the present, we see a complex set of interactions affecting an initially rich but vulnerable fauna. The total evidence refutes any simple, unicausal (e.g. hunting/habitat destruction/climate change) explanation of megafaunal extinctions, yet unequivocally supports a major role – both direct and indirect – for humans as the trigger of the extinction process. It also supports a change over time in the relative importance of hunting versus habitat loss, and in the trophic characteristics of the primate communities in Madagascar.
Biodiversity, Phylogeography, Biogeography and Conservation: Lemurs as an Example
Authors: Thalmann Urs
Published: September 2007

The lemurs of Madagascar represent a spectacular example of adaptive radiation among primates. Given the special setting under which they evolved (i.e. long isolation, geographical location, geological relief), they provide excellent models for study in many realms, and at different levels and scales, including diversity. At the same time, they occur in a ‘hottest hot spot’ region for biodiversity conservation. Although there is no single definition of biodiversity, the most commonly used units to measure biodiversity are species – species richness, species abundance and, for conservation purposes in particular, species endemism. However, what a species actually is or how, precisely, it should be defined are unresolved issues. Many species concepts have been proposed and several have been used in primatology in recent years. Nowadays, one of the more common approaches to measuring diversity, and eventually inferring species status, is to look at genetic diversity as reflected by mitochondrial DNA differences. Not enough attention has been paid, however, to the different levels at which genetic differences may occur. Lemurs provide instructive examples to highlight the questions involved in species recognition and definition. Using lemurs as examples, I will highlight the strengths and limitations of some analytical tools, including phylogeography and cladistic biogeography and, I will, in particular, emphasize the questions arising at the interface of scientific and conservation perceptions, both of which influence decisions in the field of biodiversity preservation.
Serial Diffusion Tensor Imaging Detects White Matter Changes That Correlate with Motor Outcome in Premature Infants
Authors: Drobyshevsky Alexander , Bregman Joanne , Storey Pippa , Meyer Joel , Prasad P.V. , Derrick Matthew , MacKendrick William , Tan Sidhartha
Published: September 2007

The objective of the study was to assess predictive value of serial diffusion tensor MRI (DTI) for the white matter injury and neurodevelopmental outcome in a cohort of premature infants. Twenty-four infants less than 32 weeks’ gestation were stratified to a control group (n = 11), mild brain injury with grades 1–2 of intraventricular hemorrhage (n = 6) and severe brain injury with grades 3–4 intraventricular hemorrhage (n = 4). Serial DTI studies were performed at around 30 and 36 weeks’ gestation. Fractional anisotropy (FA) and apparent diffusion coefficient were calculated. Twelve infants were followed up for developmental outcome. Developmental testing was performed with the Bayley Scales of Infant Development to obtain psychomotor index (Performance Developmental Index). Apparent diffusion coefficient was higher in the severe injury group at the second MRI in the central and occipital white matter, and corona radiata; FA was lower in optic radiation compared to controls. Performance Developmental Indexscore correlated with FA on the scan taken at the 30th week and inversely with the change of FA between scans in internal capsule and occipital white matter. A low value of FA at 30 weeks and a higher change of FA predicted less favorable motor outcome at 2 years and suggests that early subtle white matter injury can be detected in premature infants even without obvious signs of injury.