Woody lianas increase in dominance and maintain compositional integrity across an Amazonian dam-induced fragmented landscape

Tropical forest fragmentation creates insular biological communities that undergo species loss and changes in community composition over time, due to area- and edge-effects. Woody lianas thrive in degraded and secondary forests, due to their competitive advantage over trees in these habitats. Lianas compete both directly and indirectly with trees, increasing tree mortality and turnover. Despite our growing understanding of liana-tree dynamics, we lack detailed knowledge of the assemblage-level responses of lianas themselves to fragmentation, particularly in evergreen tropical forests. We examine the responses of both sapling and mature liana communities to landscape-scale forest insularization induced by a mega hydroelectric dam in the Brazilian Amazon. Detailed field inventories were conducted on islands created during reservoir filling, and in nearby mainland continuous forest. We assess the relative importance of variables associated with habitat fragmentation such as area, isolation, surrounding forest cover, fire and wind disturbance, on liana community attributes including abundance, basal area, diversity, and composition. We also explore patterns of liana dominance relative to tree saplings and adults ≥10 cm diameter at breast height. We find that 1) liana community composition remains remarkably similar across mainland continuous forest and islands, regardless of extreme area- and edge- effects and the loss of vertebrate dispersers in the latter; and 2) lianas are increasing in dominance relative to trees in the sapling layer in the most degraded islands, with both the amount of forest cover surrounding islands and fire disturbance history predicting liana dominance. Our data suggest that liana communities persist intact in isolated forests, regardless of extreme area- and edge-effects; while in contrast, tree communities simultaneously show evidence of increased turnover and supressed recruitment. These processes may lead to lianas becoming a dominant component of this dam-induced fragmented landscape in the future, due to their competitive advantage over trees in degraded forest habitats. Additional loss of tree biomass and diversity brought about through competition with lianas, and the concurrent loss of carbon storage, should be accounted for in impact assessments of future dam development

A computational study on outliers in world music

The comparative analysis of world music cultures has been the focus of several ethnomusicological studies in the last century. With the advances of Music Information Retrieval and the increased accessibility of sound archives, large-scale analysis of world music with computational tools is today feasible. We investigate music similarity in a corpus of 8200 recordings of folk and traditional music from 137 countries around the world. In particular, we aim to identify music recordings that are most distinct compared to the rest of our corpus. We refer to these recordings as ‘outliers’. We use signal processing tools to extract music information from audio recordings, data mining to quantify similarity and detect outliers, and spatial statistics to account for geographical correlation. Our findings suggest that Botswana is the country with the most distinct recordings in the corpus and China is the country with the most distinct recordings when considering spatial correlation. Our analysis includes a comparison of musical attributes and styles that contribute to the ‘uniqueness’ of the music of each country

Sexual uses of alcohol and drugs and the associated health risks: A cross sectional study of young people in nine European cities

<p>Abstract</p> <p>Background</p> <p>Young people in European countries are experiencing high levels of alcohol and drug use and escalating levels of sexually transmitted infections. Individually these represent major public health priorities. Understanding of the association between sex and substance use, and specifically the strategic roles for which young people utilise substances to facilitate sexual activity, remains limited.</p> <p>Methods</p> <p>Respondent driven sampling methodology was used in nine European cities to survey 1,341 16–35 year olds representing youth and younger adults who routinely engage in nightlife. Participants self-completed questionnaires, designed to gather demographic, social, and behavioural data on historic and current substance use and sexual behaviour.</p> <p>Results</p> <p>Respondents reported strategic use of specific substances for different sexual purposes. Substances differed significantly in the purposes for which each was deployed (e.g. 28.6% of alcohol users use it to facilitate sexual encounters; 26.2% of cocaine users use it to prolong sex) with user demographics also relating to levels of sexual use (e.g. higher levels of: ecstasy use by males to prolong sex; cocaine use by single individuals to enhance sensation and arousal). Associations between substance use and sex started at a young age, with alcohol, cannabis, cocaine or ecstasy use before age 16 all being associated with having had sex before the age of 16 (odds ratios, 3.47, 4.19, 5.73, 9.35 respectively). However, sexes differed and substance use under 16 years was associated with a proportionately greater increase in early sex amongst girls. Respondents' current drug use was associated with having multiple sexual partners. Thus, for instance, regular cocaine users (c.f. never users) were over five times more likely to have had five or more sexual partners in the last 12 months or have paid for sex.</p> <p>Conclusion</p> <p>An epidemic of recreational drug use and binge drinking exposes millions of young Europeans to routine consumption of substances which alter their sexual decisions and increase their chances of unsafe and regretted sex. For many, substance use has become an integral part of their strategic approach to sex, locking them into continued use. Tackling substances with both physiological and psychological links to sex requires approaching substance use and sexual behaviour in the same way that individuals experience them; as part of the same social process.</p

Vaccine delivery by penetratin: mechanism of antigen presentation by dendritic cells

Cell-penetrating peptides (CPP) or membrane-translocating peptides such as penetratin from Antennapedia homeodomain or TAT from human immunodeficiency virus are useful vectors for the delivery of protein antigens or their cytotoxic (Tc) or helper (Th) T cell epitopes to antigen-presenting cells. Mice immunized with CPP containing immunogens elicit antigen-specific Tc and/or Th responses and could be protected from tumor challenges. In the present paper, we investigate the mechanism of class I and class II antigen presentation of ovalbumin covalently linked to penetratin (AntpOVA) by bone marrow-derived dendritic cells with the use of biochemical inhibitors of various pathways of antigen processing and presentation. Results from our study suggested that uptake of AntpOVA is via a combination of energy-independent (membrane fusion) and energy-dependent pathways (endocytosis). Once internalized by either mechanism, multiple tap-dependent or independent antigen presentation pathways are accessed while not completely dependent on proteasomal processing but involving proteolytic trimming in the ER and Golgi compartments. Our study provides an understanding on the mechanism of antigen presentation mediated by CPP and leads to greater insights into future development of vaccine formulations

High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis

Collagen synthesis is severely diminished in osteoarthritis; thus, enhancing it may help the regeneration of cartilage. This requires large amounts of glycine, proline and lysine. Previous works of our group have shown that glycine is an essential amino acid, which must be present in the diet in large amounts to satisfy the demands for collagen synthesis. Other authors have shown that proline is conditionally essential. In this work we studied the effect of these amino acids on type II collagen synthesis. Bovine articular chondrocytes were cultured under a wide range of different concentrations of glycine, proline and lysine. Chondrocytes were characterized by type II collagen immunocytochemistry of confluence monolayer cultures. Cell growth and viability were assayed by trypan blue dye exclusion method. Type II collagen was measured in the monolayer, every 48 h for 15 days by ELISA. Increase in concentrations of proline and lysine in the culture medium enhances the synthesis of type II collagen at low concentrations, but these effects decay before 1.0 mM. Increase of glycine as of 1.0 mM exceeds these effects and this increase continues more persistently by 60–75%. Since the large effects produced by proline and lysine are within the physiological range, while the effect of glycine corresponds to a much higher range, these results demonstrated a severe glycine deficiency for collagen synthesis. Thus, increasing glycine in the diet may well be a strategy for helping cartilage regeneration by enhancing collagen synthesis, which could contribute to the treatment and prevention of osteoarthriti

Peer substance use overestimation among French university students: a cross-sectional survey

<p>Abstract</p> <p>Background</p> <p>Normative misperceptions have been widely documented for alcohol use among U.S. college students. There is less research on other substances or European cultural contexts. This study explores which factors are associated with alcohol, tobacco and cannabis use misperceptions among French college students, focusing on substance use.</p> <p>Methods</p> <p>12 classes of second-year college students (n = 731) in sociology, medicine, nursing or foreign language estimated the proportion of tobacco, cannabis, alcohol use and heavy episodic drinking among their peers and reported their own use.</p> <p>Results</p> <p>Peer substance use overestimation frequency was 84% for tobacco, 55% for cannabis, 37% for alcohol and 56% for heavy episodic drinking. Cannabis users (p = 0.006), alcohol (p = 0.003) and heavy episodic drinkers (p = 0.002), are more likely to overestimate the prevalence of use of these consumptions. Tobacco users are less likely to overestimate peer prevalence of smoking (p = 0.044). Women are more likely to overestimate tobacco (p < 0.001) and heavy episodic drinking (p = 0.007) prevalence. Students having already completed another substance use questionnaire were more likely to overestimate alcohol use prevalence (p = 0.012). Students exposed to cannabis prevention campaigns were more likely to overestimate cannabis (p = 0.018) and tobacco use (p = 0.022) prevalence. Other identified factors are class-level use prevalences and academic discipline.</p> <p>Conclusions</p> <p>Local interventions that focus on creating realistic perceptions of substance use prevalence could be considered for cannabis and alcohol prevention in French campuses.</p

Prevalence of hallux valgus in the general population: a systematic review and meta-analysis

BACKGROUND: Hallux valgus (HV) is a foot deformity commonly seen in medical practice, often accompanied by significant functional disability and foot pain. Despite frequent mention in a diverse body of literature, a precise estimate of the prevalence of HV is difficult to ascertain. The purpose of this systematic review was to investigate prevalence of HV in the overall population and evaluate the influence of age and gender. METHODS: Electronic databases (Medline, Embase, and CINAHL) and reference lists of included papers were searched to June 2009 for papers on HV prevalence without language restriction. MeSH terms and keywords were used relating to HV or bunions, prevalence and various synonyms. Included studies were surveys reporting original data for prevalence of HV or bunions in healthy populations of any age group. Surveys reporting prevalence data grouped with other foot deformities and in specific disease groups (e.g. rheumatoid arthritis, diabetes) were excluded. Two independent investigators quality rated all included papers on the Epidemiological Appraisal Instrument. Data on raw prevalence, population studied and methodology were extracted. Prevalence proportions and the standard error were calculated, and meta-analysis was performed using a random effects model. RESULTS: A total of 78 papers reporting results of 76 surveys (total 496,957 participants) were included and grouped by study population for meta-analysis. Pooled prevalence estimates for HV were 23% in adults aged 18-65 years (CI: 16.3 to 29.6) and 35.7% in elderly people aged over 65 years (CI: 29.5 to 42.0). Prevalence increased with age and was higher in females [30% (CI: 22 to 38)] compared to males [13% (CI: 9 to 17)]. Potential sources of bias were sampling method, study quality and method of HV diagnosis. CONCLUSIONS: Notwithstanding the wide variation in estimates, it is evident that HV is prevalent; more so in females and with increasing age. Methodological quality issues need to be addressed in interpreting reports in the literature and in future research

Effects of Transport Inhibitors on the Cellular Uptake of Carboxylated Polystyrene Nanoparticles in Different Cell Lines

Nanotechnology is expected to play a vital role in the rapidly developing field of nanomedicine, creating innovative solutions and therapies for currently untreatable diseases, and providing new tools for various biomedical applications, such as drug delivery and gene therapy. In order to optimize the efficacy of nanoparticle (NP) delivery to cells, it is necessary to understand the mechanisms by which NPs are internalized by cells, as this will likely determine their ultimate sub-cellular fate and localisation. Here we have used pharmacological inhibitors of some of the major endocytic pathways to investigate nanoparticle uptake mechanisms in a range of representative human cell lines, including HeLa (cervical cancer), A549 (lung carcinoma) and 1321N1 (brain astrocytoma). Chlorpromazine and genistein were used to inhibit clathrin and caveolin mediated endocytosis, respectively. Cytochalasin A and nocodazole were used to inhibit, respectively, the polymerisation of actin and microtubule cytoskeleton. Uptake experiments were performed systematically across the different cell lines, using carboxylated polystyrene NPs of 40 nm and 200 nm diameters, as model NPs of sizes comparable to typical endocytic cargoes. The results clearly indicated that, in all cases and cell types, NPs entered cells via active energy dependent processes. NP uptake in HeLa and 1321N1 cells was strongly affected by actin depolymerisation, while A549 cells showed a stronger inhibition of NP uptake (in comparison to the other cell types) after microtubule disruption and treatment with genistein. A strong reduction of NP uptake was observed after chlorpromazine treatment only in the case of 1321N1 cells. These outcomes suggested that the same NP might exploit different uptake mechanisms to enter different cell types

Mechanisms Underlying the Confined Diffusion of Cholera Toxin B-Subunit in Intact Cell Membranes

Multivalent glycolipid binding toxins such as cholera toxin have the capacity to cluster glycolipids, a process thought to be important for their functional uptake into cells. In contrast to the highly dynamic properties of lipid probes and many lipid-anchored proteins, the B-subunit of cholera toxin (CTxB) diffuses extremely slowly when bound to its glycolipid receptor GM1 in the plasma membrane of living cells. In the current study, we used confocal FRAP to examine the origins of this slow diffusion of the CTxB/GM1 complex at the cell surface, relative to the behavior of a representative GPI-anchored protein, transmembrane protein, and fluorescent lipid analog. We show that the diffusion of CTxB is impeded by actin- and ATP-dependent processes, but is unaffected by caveolae. At physiological temperature, the diffusion of several cell surface markers is unchanged in the presence of CTxB, suggesting that binding of CTxB to membranes does not alter the organization of the plasma membrane in a way that influences the diffusion of other molecules. Furthermore, diffusion of the B-subunit of another glycolipid-binding toxin, Shiga toxin, is significantly faster than that of CTxB, indicating that the confined diffusion of CTxB is not a simple function of its ability to cluster glycolipids. By identifying underlying mechanisms that control CTxB dynamics at the cell surface, these findings help to delineate the fundamental properties of toxin-receptor complexes in intact cell membranes