title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=1798 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Metaproteomics of saliva identifies human protein markers specific for individuals with periodontitis and dental caries compared to orally healthy controls link: https://peerj.com/articles/2433 last-modified: 2016-09-14 description: BackgroundThe composition of the salivary microbiota has been reported to differentiate between patients with periodontitis, dental caries and orally healthy individuals. To identify characteristics of diseased and healthy saliva we thus wanted to compare saliva metaproteomes from patients with periodontitis and dental caries to healthy individuals.MethodsStimulated saliva samples were collected from 10 patients with periodontitis, 10 patients with dental caries and 10 orally healthy individuals. The proteins in the saliva samples were subjected to denaturing buffer and digested enzymatically with LysC and trypsin. The resulting peptide mixtures were cleaned up by solid-phase extraction and separated online with 2 h gradients by nano-scale C18 reversed-phase chromatography connected to a mass spectrometer through an electrospray source. The eluting peptides were analyzed on a tandem mass spectrometer operated in data-dependent acquisition mode.ResultsWe identified a total of 35,664 unique peptides from 4,161 different proteins, of which 1,946 and 2,090 were of bacterial and human origin, respectively. The human protein profiles displayed significant overexpression of the complement system and inflammatory markers in periodontitis and dental caries compared to healthy controls. Bacterial proteome profiles and functional annotation were very similar in health and disease.ConclusionsOverexpression of proteins related to the complement system and inflammation seems to correlate with oral disease status. Similar bacterial proteomes in healthy and diseased individuals suggests that the salivary microbiota predominantly thrives in a planktonic state expressing no disease-associated characteristics of metabolic activity. creator: Daniel Belstrøm creator: Rosa R. Jersie-Christensen creator: David Lyon creator: Christian Damgaard creator: Lars J. Jensen creator: Palle Holmstrup creator: Jesper V. Olsen uri: https://doi.org/10.7717/peerj.2433 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2016 Belstrøm et al. title: Resilience does not explain the dissociation between chronic pain and physical activity in South Africans living with HIV link: https://peerj.com/articles/2464 last-modified: 2016-09-13 description: Pain burden is high in people living with HIV (PLWH), but the effect of this pain on functionality is equivocal. Resilience, the ability to cope with adversity, may promote adaptation to pain, so we hypothesised that higher resilience would correlate with less pain-related impairment of activity. We recruited 197 black South African PLWH, 99 with chronic pain (CP) and 98 patients without. We measured pain intensity and interference using the Brief Pain Inventory, and resilience using the Resilience Scale. Participants were generally highly resilient. Greater resilience correlated with better health-related quality of life, but not with pain intensity or interference. We also measured physical activity objectively, by actigraphy, in a subset of patients (37 with chronic pain and 31 without chronic pain), who wore accelerometers for two weeks. There was no difference in duration or intensity of activity between those with and without pain, and activity was not associated with resilience. In this sample, pain was not associated with altered physical activity. Resilience did not explain differences in pain intensity or pain interference but was associated with improved quality of life. Financial stresses and the fear of HIV stigma may have driven patients to conceal pain and to suppress its expected impairment of activity. creator: Antonia L. Wadley creator: Duncan Mitchell creator: Peter R. Kamerman uri: https://doi.org/10.7717/peerj.2464 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2016 Wadley et al. title: Lowland tapir distribution and habitat loss in South America link: https://peerj.com/articles/2456 last-modified: 2016-09-13 description: The development of species distribution models (SDMs) can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative different Habitat Suitability Maps for the lowland tapir. While MAXENT was efficient at identifying areas as suitable or unsuitable, it was less efficient (when compared to the results by ENFA) at identifying the gradient of habitat suitability. MAXENT is a more multifaceted technique that establishes more complex relationships between dependent and independent variables. Our results demonstrate that for at least one species, the lowland tapir, the use of a simple consensual approach (average of ENFA and MAXENT models outputs) better reflected its current distribution patterns. The Brazilian ecoregions have the highest habitat loss for the tapir. Cerrado and Atlantic Forest account for nearly half (48.19%) of the total area lost. The Amazon region contains the largest area under protection, and the most extensive remaining habitat for the tapir, but also showed high levels of habitat loss outside protected areas, which increases the importance of support for proper management. creator: Jose Luis Passos Cordeiro creator: José M.V. Fragoso creator: Danielle Crawshaw creator: Luiz Flamarion B. Oliveira uri: https://doi.org/10.7717/peerj.2456 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2016 Cordeiro et al. title: An association between feather damaging behavior and corticosterone metabolite excretion in captive African grey parrots (Psittacus erithacus) link: https://peerj.com/articles/2462 last-modified: 2016-09-13 description: BackgroundAfrican grey parrots (Psittacus erithacus) are kept as pets and are frequently hand-reared. It has been observed that hand-reared African grey parrots may develop behavioral disorders such as feather damaging behavior (FDB). It is well known that chronic stress is involved in behavioral disorders in captive parrots. The main glucocorticoid in birds is corticosterone; its quantification provides information about adrenocortical activity and is considered to be a reliable indicator of stress levels in birds. We analyzed the differences in the excretion of corticosterone metabolites (CM) in the droppings of African grey parrots characterized by: 1. different rearing histories (parent rearing vs. hand rearing); and 2. the presence or absence of FDB in hand-reared parrots.MethodsA total of 82 African grey parrots that were kept in captivity were considered. According to breeding methods, three groups of birds were defined: 1. The parent-reared (PR) parrots included birds kept in pairs (n = 30 pairs) with a conspecific partner of the opposite sex. All of these birds were healthy and never showed FDB signs; 2. The healthy hand-reared parrots (H-HR) included pet parrots individually kept, that were hand-reared and did not display any sign of FDB (n = 11, 7 males and 4 females); 3. The FDB hand-reared parrot (FDB-HR) included pet parrots individually kept, that were hand-reared and displayed FDB (n = 11, 7 males and 4 females). Droppings were collected in the morning over three alternating days in autumn 2014 and spring 2015. The CM were determined using a multi-species corticosterone enzyme immunoassay kit. Split-plot repeated-measure ANOVA was used to examine any differences using group, season and group × season as the main factors.ResultsDifferent quantities of CM in droppings were found for the three groups. The mean CM value was 587 ng/g in the PR parrots, 494 ng/g in the H-HR parrots and 1,744 ng/g in the FDB-HR parrots, irrespective of the season. The excretion of CM in FDB-HR was significantly higher than in PR or H-HR parrots. CM in droppings were not influenced by the season (autumn vs. spring); furthermore, the interaction between group and sampling season was not significant. Limited to the H-HR and FDB-HR groups, a trend in the significance of the difference in the mean CM excreted by male and female birds was observed, with the levels excreted by males being higher than those excreted by females. When the effect of age was considered (in the two separate groups), there was a statistically significant positive correlation only for H-HR.ConclusionsThe highest amount of CM excretion was found in FDB-HR parrots, and a positive correlation between age and CM excretion was found in H-HR. Given that the CM excretion of both PR and H-HR parrots was similar in our study, future research is recommended to investigate the specific aspects of hand-rearing to improve parrot welfare. creator: Pierluca Costa creator: Elisabetta Macchi creator: Emanuela Valle creator: Michele De Marco creator: Daniele M. Nucera creator: Laura Gasco creator: Achille Schiavone uri: https://doi.org/10.7717/peerj.2462 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2016 Costa et al. title: Regional drivers of clutch loss reveal important trade-offs for beach-nesting birds link: https://peerj.com/articles/2460 last-modified: 2016-09-13 description: Coastal birds are critical ecosystem constituents on sandy shores, yet are threatened by depressed reproductive success resulting from direct and indirect anthropogenic and natural pressures. Few studies examine clutch fate across the wide range of environments experienced by birds; instead, most focus at the small site scale. We examine survival of model shorebird clutches as an index of true clutch survival at a regional scale (∼200 km), encompassing a variety of geomorphologies, predator communities, and human use regimes in southeast Queensland, Australia. Of the 132 model nests deployed and monitored with cameras, 45 (34%) survived the experimental exposure period. Thirty-five (27%) were lost to flooding, 32 (24%) were depredated, nine (7%) buried by sand, seven (5%) destroyed by people, three (2%) failed by unknown causes, and one (1%) was destroyed by a dog. Clutch fate differed substantially among regions, particularly with respect to losses from flooding and predation. ‘Topographic’ exposure was the main driver of mortality of nests placed close to the drift line near the base of dunes, which were lost to waves (particularly during storms) and to a lesser extent depredation. Predators determined the fate of clutches not lost to waves, with the depredation probability largely influenced by region. Depredation probability declined as nests were backed by higher dunes and were placed closer to vegetation. This study emphasizes the scale at which clutch fate and survival varies within a regional context, the prominence of corvids as egg predators, the significant role of flooding as a source of nest loss, and the multiple trade-offs faced by beach-nesting birds and those that manage them. creator: Brooke Maslo creator: Thomas A. Schlacher creator: Michael A. Weston creator: Chantal M. Huijbers creator: Chris Anderson creator: Ben L. Gilby creator: Andrew D. Olds creator: Rod M. Connolly creator: David S. Schoeman uri: https://doi.org/10.7717/peerj.2460 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2016 Maslo et al. title: Canopy position has a profound effect on soybean seed composition link: https://peerj.com/articles/2452 last-modified: 2016-09-13 description: Although soybean seeds appear homogeneous, their composition (protein, oil and mineral concentrations) can vary significantly with the canopy position where they were produced. In studies with 10 cultivars grown over a 3-yr period, we found that seeds produced at the top of the canopy have higher concentrations of protein but less oil and lower concentrations of minerals such as Mg, Fe, and Cu compared to seeds produced at the bottom of the canopy. Among cultivars, mean protein concentration (average of different positions) correlated positively with mean concentrations of S, Zn and Fe, but not other minerals. Therefore, on a whole plant basis, the uptake and allocation of S, Zn and Fe to seeds correlated with the production and allocation of reduced N to seed protein; however, the reduced N and correlated minerals (S, Zn and Fe) showed different patterns of allocation among node positions. For example, while mean concentrations of protein and Fe correlated positively, the two parameters correlated negatively in terms of variation with canopy position. Altering the microenvironment within the soybean canopy by removing neighboring plants at flowering increased protein concentration in particular at lower node positions and thus altered the node-position gradient in protein (and oil) without altering the distribution of Mg, Fe and Cu, suggesting different underlying control mechanisms. Metabolomic analysis of developing seeds at different positions in the canopy suggests that availability of free asparagine may be a positive determinant of storage protein accumulation in seeds and may explain the increased protein accumulation in seeds produced at the top of the canopy. Our results establish node-position variation in seed constituents and provide a new experimental system to identify genes controlling key aspects of seed composition. In addition, our results provide an unexpected and simple approach to link agronomic practices to improve human nutrition and health in developing countries because food products produced from seeds at the bottom of the canopy contained higher Fe concentrations than products from the top of the canopy. Therefore, using seeds produced in the lower canopy for production of iron-rich soy foods for human consumption could be important when plants are the major source of protein and human diets can be chronically deficient in Fe and other minerals. creator: Steven C. Huber creator: Kunzhi Li creator: Randall Nelson creator: Alexander Ulanov creator: Catherine M. DeMuro creator: Ivan Baxter uri: https://doi.org/10.7717/peerj.2452 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2016 Huber et al. title: Tissue and serum samples of patients with papillary thyroid cancer with and without benign background demonstrate different altered expression of proteins link: https://peerj.com/articles/2450 last-modified: 2016-09-13 description: BackgroundPapillary thyroid cancer (PTC) is mainly diagnosed using fine-needle aspiration biopsy. This most common form of well-differentiated thyroid cancer occurs with or without a background of benign thyroid goiter (BTG).MethodsIn the present study, a gel-based proteomics analysis was performed to analyse the expression of proteins in tissue and serum samples of PTC patients with (PTCb; n = 6) and without a history of BTG (PTCa; n = 8) relative to patients with BTG (n = 20). This was followed by confirmation of the levels of proteins which showed significant altered abundances of more than two-fold difference (p < 0.01) in the tissue and serum samples of the same subjects using ELISA.ResultsThe data of our study showed that PTCa and PTCb distinguish themselves from BTG in the types of tissue and serum proteins of altered abundance. While higher levels of alpha-1 antitrypsin (A1AT) and heat shock 70 kDa protein were associated with PTCa, lower levels of A1AT, protein disulfide isomerase and ubiquitin-conjugating enzyme E2 N seemed apparent in the PTCb. In case of the serum proteins, higher abundances of A1AT and alpha 1-beta glycoprotein were detected in PTCa, while PTCb was associated with enhanced apolipoprotein A-IV and alpha 2-HS glycoprotein (AHSG). The different altered expression of tissue and serum A1AT as well as serum AHSG between PTCa and PTCb patients were also validated by ELISA.DiscussionThe distinctive altered abundances of the tissue and serum proteins form preliminary indications that PTCa and PTCb are two distinct cancers of the thyroid that are etiologically and mechanistically different although it is currently not possible to rule out that they may also be due other reasons such as the different stages of the malignant disease. These proteins stand to have a potential use as tissue or serum biomarkers to discriminate the three different thyroid neoplasms although this requires further validation in clinically representative populations. creator: Mardiaty Iryani Abdullah creator: Ching Chin Lee creator: Sarni Mat Junit creator: Khoon Leong Ng creator: Onn Haji Hashim uri: https://doi.org/10.7717/peerj.2450 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2016 Abdullah et al. title: Genetic signatures of ecological diversity along an urbanization gradient link: https://peerj.com/articles/2444 last-modified: 2016-09-13 description: Despite decades of work in environmental science and ecology, estimating human influences on ecosystems remains challenging. This is partly due to complex chains of causation among ecosystem elements, exacerbated by the difficulty of collecting biological data at sufficient spatial, temporal, and taxonomic scales. Here, we demonstrate the utility of environmental DNA (eDNA) for quantifying associations between human land use and changes in an adjacent ecosystem. We analyze metazoan eDNA sequences from water sampled in nearshore marine eelgrass communities and assess the relationship between these ecological communities and the degree of urbanization in the surrounding watershed. Counter to conventional wisdom, we find strongly increasing richness and decreasing beta diversity with greater urbanization, and similar trends in the diversity of life histories with urbanization. We also find evidence that urbanization influences nearshore communities at local (hundreds of meters) rather than regional (tens of km) scales. Given that different survey methods sample different components of an ecosystem, we then discuss the advantages of eDNA—which we use here to detect hundreds of taxa simultaneously—as a complement to traditional ecological sampling, particularly in the context of broad ecological assessments where exhaustive manual sampling is impractical. Genetic data are a powerful means of uncovering human-ecosystem interactions that might otherwise remain hidden; nevertheless, no sampling method reveals the whole of a biological community. creator: Ryan P. Kelly creator: James L. O’Donnell creator: Natalie C. Lowell creator: Andrew O. Shelton creator: Jameal F. Samhouri creator: Shannon M. Hennessey creator: Blake E. Feist creator: Gregory D. Williams uri: https://doi.org/10.7717/peerj.2444 license: http://creativecommons.org/publicdomain/zero/1.0/ rights: title: Comparative cephalopod shell strength and the role of septum morphology on stress distribution link: https://peerj.com/articles/2434 last-modified: 2016-09-13 description: The evolution of complexly folded septa in ammonoids has long been a controversial topic. Explanations of the function of these folded septa can be divided into physiological and mechanical hypotheses with the mechanical functions tending to find widespread support. The complexity of the cephalopod shell has made it difficult to directly test the mechanical properties of these structures without oversimplification of the septal morphology or extraction of a small sub-domain. However, the power of modern finite element analysis now permits direct testing of mechanical hypothesis on complete, empirical models of the shells taken from computed tomographic data. Here we compare, for the first time using empirical models, the capability of the shells of extant Nautilus pompilius, Spirula spirula, and the extinct ammonite Cadoceras sp. to withstand hydrostatic pressure and point loads. Results show hydrostatic pressure imparts highest stress on the final septum with the rest of the shell showing minimal compression. S. spirula shows the lowest stress under hydrostatic pressure while N. pompilius shows the highest stress. Cadoceras sp. shows the development of high stress along the attachment of the septal saddles with the shell wall. Stress due to point loads decreases when the point force is directed along the suture as opposed to the unsupported chamber wall. Cadoceras sp. shows the greatest decrease in stress between the point loads compared to all other models. Greater amplitude of septal flutes corresponds with greater stress due to hydrostatic pressure; however, greater amplitude decreases the stress magnitude of point loads directed along the suture. In our models, sutural complexity does not predict greater resistance to hydrostatic pressure but it does seem to increase resistance to point loads, such as would be from predators. This result permits discussion of palaeoecological reconstructions on the basis of septal morphology. We further suggest that the ratio used to characterize septal morphology in the septal strength index and in calculations of tensile strength of nacre are likely insufficient. A better understanding of the material properties of cephalopod nacre may allow the estimation of maximum depth limits of shelled cephalopods through finite element analysis. creator: Robert Lemanis creator: Stefan Zachow creator: René Hoffmann uri: https://doi.org/10.7717/peerj.2434 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2016 Lemanis et al. title: Characterization of novel bacteriophage phiC119 capable of lysing multidrug-resistant Shiga toxin-producing Escherichia coli O157:H7 link: https://peerj.com/articles/2423 last-modified: 2016-09-13 description: BackgroundShiga toxin-producing Escherichia coli (STEC) is one of the most common and widely distributed foodborne pathogens that has been frequently implicated in gastrointestinal and urinary tract infections. Moreover, high rates of multiple antibiotic-resistant E. coli strains have been reported worldwide. Due to the emergence of antibiotic-resistant strains, bacteriophages are considered an attractive alternative to biocontrol pathogenic bacteria. Characterization is a preliminary step towards designing a phage for biocontrol.MethodsIn this study, we describe the characterization of a bacteriophage designated phiC119, which can infect and lyse several multidrug-resistant STEC strains and some Salmonella strains. The phage genome was screened to detect the stx-genes using PCR, morphological analysis, host range was determined, and genome sequencing were carried out, as well as an analysis of the cohesive ends and identification of the type of genetic material through enzymatic digestion of the genome.ResultsAnalysis of the bacteriophage particles by transmission electron microscopy showed that it had an icosahedral head and a long tail, characteristic of the family Siphoviridae. The phage exhibits broad host range against multidrug-resistant and highly virulent E. coli isolates. One-step growth experiments revealed that the phiC119 phage presented a large burst size (210 PFU/cell) and a latent period of 20 min. Based on genomic analysis, the phage contains a linear double-stranded DNA genome with a size of 47,319 bp. The phage encodes 75 putative proteins, but lysogeny and virulence genes were not found in the phiC119 genome.ConclusionThese results suggest that phage phiC119 may be a good biological control agent. However, further studies are required to ensure its control of STEC and to confirm the safety of phage use. creator: Luis Amarillas creator: Cristóbal Chaidez creator: Arturo González-Robles creator: Yadira Lugo-Melchor creator: Josefina León-Félix uri: https://doi.org/10.7717/peerj.2423 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2016 Amarillas et al.