bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contrasting effects of high‐intensity photosynthetically active radiation on two bloom‐forming dinoflagellates
Authors: Cooney Elizabeth C. , Fredrickson Kerri A. , Bright Kelley J. , Strom Suzanne L. 
Published: June 2019

While light limitation can inhibit bloom formation in dinoflagellates, the potential for high‐intensity photosynthetically active radiation (PAR) to inhibit blooms by causing stress or damage has not been well‐studied. We measured the effects of high‐intensity PAR on the bloom‐forming dinoflagellates Alexandrium fundyense and Heterocapsa rotundata. Various physiological parameters (photosynthetic efficiency Fv/Fm, cell permeability, dimethylsulfoniopropionate [DMSP], cell volume, and chlorophyll‐a content) were measured before and after exposure to high‐intensity natural sunlight in short‐term light stress experiments. In addition, photosynthesis‐irradiance (P‐E) responses were compared for cells grown at different light levels to assess the capacity for photophysiological acclimation in each species. Experiments revealed distinct species‐specific responses to high PAR. While high light decreased Fv/Fm in both species, A. fundyense showed little additional evidence of light stress in short‐term experiments, although increased membrane permeability and intracellular DMSP indicated a response to handling. P‐E responses further indicated a high light‐adapted species with Chl‐a inversely proportional to growth irradiance and no evidence of photoinhibition; reduced maximum per‐cell photosynthesis rates suggest a trade‐off between photoprotection and C fixation in high light‐acclimated cells. Heterocapsa rotundata cells, in contrast, swelled in response to high light and sometimes lysed in short‐term experiments, releasing DMSP. P‐E responses confirmed a low light‐adapted species with high photosynthetic efficiencies associated with trade‐offs in the form of substantial photoinhibition and a lack of plasticity in Chl‐a content. These contrasting responses illustrate that high light constrains dinoflagellate community composition through species‐specific stress effects, with consequences for bloom formation and ecological interactions within the plankton.
TLL1 variants do not predict hepatocellular carcinoma development in HCV cirrhotic patients treated with direct‐acting antivirals
Authors: Degasperi Elisabetta , Galmozzi Enrico , Facchetti Floriana , Farina Elisa , D'Ambrosio Roberta , Soffredini Roberta , Iavarone Massimo , Lampertico Pietro 
Published: June 2019

AbstractTolloid‐like 1 gene (TLL1) variant rs17047200 has been associated with hepatocellular carcinoma (HCC) in Japanese hepatitis C virus (HCV) patients with sustained virological response (SVR) to interferon or direct‐acting antiviral (DAA)‐based regimens. We investigated whether this holds true also in Caucasian cirrhotic patients cured by DAAs. Consecutive Caucasian HCV cirrhotics receiving DAA between December 2014 and December 2016 in a single centre were enrolled. Cirrhosis was defined histologically (METAVIR F4) or by liver stiffness measurement (LSM > 11.9 kPa). TLL1 rs17047200 was analysed by TaqMan SNP genotyping assay. 452 patients were enrolled: median age 63 (28‐87) years, 58% males, 47% HCV‐1b, LSM 19.1 (12.0‐75.0) kPa and Fibrosis‐4 (FIB‐4) score 4.9 (0.3‐46.0). 96% patients achieved an SVR. TLL1 genotype was AA in 329 (73%) and AT/TT in 123 (27%) (MAF = 0.14, HWE P > 0.05). Patients’ clinical features were similar across TLL1 genotypes. After 33 (3‐47) months from DAA start, 31 patients developed HCC, with a 3‐year estimated cumulative probability being 7.5% (95% CI: 5%‐10%). The cumulative incidence of HCC was 9% in TLL1 AA vs 7% in AT/TT patients (P = 0.55). Male sex (HR: 3.78, 95% CI: 1.4‐10.1, P = 0.008), diabetes (HR: 3.5, 95% CI: 1.68‐7.27, P = 0.001) and FIB‐4 (HR: 1.09, 95% CI: 1.03‐1.14, P = 0.001) were baseline‐independent predictors of HCC. The incidence of HCC was not influenced by TLL1 genotypes even when considering an additional group of 348 noncirrhotic patients, being 2% in AA vs 1% AT/TT patients (P = 0.58). In a large cohort of Caucasian HCV cirrhotics treated with DAA, TLL1 variants do not predict HCC development.
Pharmacokinetic profile of amoxicillin and its glucuronide‐like metabolite when administered subcutaneously to koalas (Phascolarctos cinereus)
Authors: Kimble Benjamin , Vogelnest Larry , Gharibi Soraya , Izes Aaron M. , Govendir Merran 
Published: June 2019

AbstractAmoxicillin was administered as a single subcutaneous injection at 12.5 mg/kg to four koalas and changes in amoxicillin plasma concentrations over 24 hr were quantified. Amoxicillin had a relatively low average ± SD maximum plasma concentration (Cmax) of 1.72 ± 0.47 µg/ml; at an average ± SD time to reach Cmax (Tmax) of 2.25 ± 1.26 hr, and an elimination half‐life of 4.38 ± 2.40 hr. The pharmacokinetic profile indicated relatively poor subcutaneous absorption. A metabolite was also identified, likely associated with glucuronic acid conjugation. Bacterial growth inhibition assays demonstrated that all plasma samples other than t = 0 hr, inhibited the growth of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 to some extent. Calculated pharmacokinetic indices were used to predict whether this dose could attain a plasma concentration to inhibit some susceptible Gram‐negative and Gram‐positive pathogens. It was predicted that a twice daily dose of 12.5 mg/kg would be efficacious to inhibit susceptible bacteria with an amoxicillin minimum inhibitory concentration (MIC) ≤ 0.75 µg/ml such as susceptible Bordetella bronchiseptica, E. coli, Staphylococcus spp. and Streptococcus spp. pathogens.
Similarities between invaders and native species: Moving past Darwin's naturalization conundrum
Authors: Bennett Jonathan A. 
Published: June 2019

AbstractDarwin's naturalization conundrum states that successful invaders must be closely related to native species to possess the traits to tolerate that environment, but distantly related enough to possess traits allowing exploitation of underutilized niches, thereby minimizing competition. Although influential, this hypothesis is based on several simplistic assumptions. In particular, the relationship among phylogenetic relatedness, similarity, and competition is more complex than assumed and changes with spatial and phylogenetic scale. Competitive interactions are determined by limiting similarity and trait hierarchies associated with separate traits. Successful invaders thus need to be similar to native species in some respects, but different in others. This combination of similarities and differences is unlikely to be conserved. Further, many invasive species are represented in their novel range by genotypes with extreme trait values or plasticity relative to the species mean. Selection for these genotypes may alter the similarity between invasive and native species, thus obscuring the relationship between competition and phylogenetic relatedness. As environmental filtering and competition often act on different spatial scales, approaches assessing how individual traits relate to invasion at these scales (species pools vs local community) may improve our understanding of the relationship between similarity and invasion.
Decreased interferon‐γ production by NK cells from KIR haplotype B carriers in hepatitis C virus infection
Authors: Mele Dalila , Pasi Annamaria , Cacciatore Rosalia , Mantovani Stefania , Oliviero Barbara , Mondelli Mario U. , Varchetta Stefania 
Published: June 2019

AbstractBackground and AimsDifferent population genetics studies showed that interactions between killer‐cell immunoglobulin‐like receptors (KIR) and HLA play a role in viral disease outcome, but functional correlates are missing. Building upon our previous work pointing to a regulatory role for KIR3DL1/DS1 in hepatitis C virus (HCV) infection, we analysed whether its expression may affect natural killer (NK) cell function in the presence or absence of its principal ligand HLA‐Bw4 in KIR haplotype A and B carriers, which are characterized by a different representation of activating and inhibitory KIRs.MethodsWe performed KIR and HLA class I genotypic analysis in 54 healthy donors (HD) and 50 HCV+ subjects and examined NK cell cytokine secretion and degranulation in the context of KIR3DL1‐HLA‐Bw4 match stratified by KIR haplotype.ResultsKIR3DL1‐HLA‐Bw4 match induced functional NK cell modulation, reflected by reduced interferon (IFN)γ production in haplotype B HCV+ patients compared to HD. This functional impairment could be ascribed to the KIR3DS1 negative HCV‐infected patient population, whose NK cells also showed a significantly decreased proportion of KIR3DL1. Haplotype A HCV‐infected patients showed increased NK cell degranulation compared with HD in the absence of KIR‐HLA‐Bw4 match and this activity was associated with increased phosphorylation of signal transducer and activator of transcription (STAT) 1.ConclusionsOur data show that NK cells from HCV+ patients have an unbalanced ability to produce IFNγ and to kill target cells in haplotype A and B carriers, suggesting the existence of complex functional differences governed by KIR‐HLA interaction, particularly on KIR3DL1 expressing NK cells.
Transcriptomic resilience, symbiont shuffling, and vulnerability to recurrent bleaching in reef‐building corals
Authors: Thomas Luke , López Elora H. , Morikawa Megan K. , Palumbi Stephen R. 
Published: June 2019

AbstractAs climate change progresses and extreme temperature events increase in frequency, rates of disturbance may soon outpace the capacity of certain species of reef‐building coral to recover from bleaching. This may lead to dramatic shifts in community composition and ecosystem function. Understanding variation in rates of bleaching recovery among species and how that translates to resilience to recurrent bleaching is fundamental to predicting the impacts of increasing disturbances on coral reefs globally. We tracked the response of two heat sensitive species in the genus Acropora to repeated bleaching events during the austral summers of 2015 and 2017. Despite a similar bleaching response, the species Acropora gemmifera recovered faster based on transcriptome‐wide gene expression patterns and had a more dynamic algal symbiont community than Acropora hyacinthus growing on the same reef. Moreover, A. gemmifera had higher survival to repeated heat extremes, with six‐fold lower mortality than A. hyacinthus. These patterns suggest that speed of recovery from a first round of bleaching, based on multiple mechanisms, contributes strongly to sensitivity to a second round of bleaching. Furthermore, our data uncovered intragenus variation in a group of corals thought generally to be heat‐sensitive and therefore paint a more nuanced view of the future health of coral reef ecosystems against a backdrop of increasing thermal disturbances.
Anthropization level of Lascaux Cave microbiome shown by regional‐scale comparisons of pristine and anthropized caves
Authors: Alonso Lise , Pommier Thomas , Kaufmann Bernard , Dubost Audrey , Chapulliot David , Doré Jeanne , Douady Christophe J. , Moënne‐Loccoz Yvan 
Published: June 2019

AbstractLimestone areas across the world develop karstic caves, which are populated by a wide range of macro‐ and microorganisms. Many of these caves display Paleolithic art or outstanding speleothems, and in the last century they have been subjected to anthropization due to touristic management and intense human frequentation. Despite their cultural importance and associated conservation issues, the impact of anthropization on cave biodiversity is not known. Here, we show that anthropization is associated with specific cave biota modifications. We compared diversity in four pristine caves, four anthropized show caves, and the iconic Lascaux Cave with even stronger anthropization. The predominant microbial higher taxa were the same in all caves, but the most anthropized cave (Lascaux) was unique as it differed from the eight others by a higher proportion of Bacteroidetes bacteria and the absence of Euryarchaeota and Woesearchaeota archaea. Anthropization resulted in lower diversity and altered community structure for bacteria and archaea on cave walls, especially in Lascaux, but with a more limited effect on microeukaryotes and arthropods. Our findings fill a key gap in our understanding of the response of karstic communities to anthropization, by revealing that tourism‐related anthropization impacts on the prokaryotic microbiome rather than on eukaryotic residents, and that it shapes cave biota irrespective of cave natural features.
Detection of environmental and morphological adaptation despite high landscape genetic connectivity in a pest grasshopper (Phaulacridium vittatum)
Authors: Yadav Sonu , Stow Adam J. , Dudaniec Rachael Y. 
Published: June 2019

AbstractWidespread species that exhibit both high gene flow and the capacity to occupy heterogeneous environments make excellent models for examining local selection processes along environmental gradients. Here we evaluate the influence of temperature and landscape variables on genetic connectivity and signatures of local adaptation in Phaulacridium vittatum, a widespread agricultural pest grasshopper, endemic to Australia. With sampling across a 900‐km latitudinal gradient, we genotyped 185 P. vittatum from 19 sites at 11,408 single nucleotide polymorphisms (SNPs) using ddRAD sequencing. Despite high gene flow across sites (pairwise FST = 0.0003–0.08), landscape genetic resistance modelling identified a positive nonlinear effect of mean annual temperature on genetic connectivity. Urban areas and water bodies had a greater influence on genetic distance among sites than pasture, agricultural areas and forest. Together, FST outlier tests and environmental association analysis (EAA) detected 242 unique SNPs under putative selection, with the highest numbers associated with latitude, mean annual temperature and body size. A combination of landscape genetic connectivity analysis together with EAA identified mean annual temperature as a key driver of both neutral gene flow and environmental selection processes. Gene annotation of putatively adaptive SNPs matched with gene functions for olfaction, metabolic detoxification and ultraviolet light shielding. Our results imply that this widespread agricultural pest has the potential to spread and adapt under shifting temperature regimes and land cover change.
An agonist of the MscL channel affects multiple bacterial species and increases membrane permeability and potency of common antibiotics
Authors: Wray Robin , Herrera Nadia , Iscla Irene , Wang Junmei , Blount Paul 
Published: June 2019

SummaryThe bacterial MscL channel normally functions as an emergency release valve discharging cytoplasmic solutes upon osmotic stress. The channel opens and passes molecules up to 30 Å and its pore is the largest of any gated channel. Opening the MscL pore inappropriately is detrimental to the bacterial cell, suggesting MscL as a potential novel drug target. A small‐molecule compound, 011A, has been shown to increase sensitivity of the Escherichia coli MscL channel, slow growth, and even decrease viability of quiescent cultures. The mscL gene is highly conserved and found in the vast majority of bacterial species, including pathogens. Here, we test the hypothesis that 011A can influence the growth and viability of other bacterial species, specifically Staphylococcus aureus and Mycobacterium smegmatis, in a MscL‐dependent manner. Furthermore, we demonstrate that the 011A compound can increase potency of other antibiotics, presumably by permeabilizing the membrane and allowing easier access of the antibiotic into the cytoplasm. Thus, MscL activators have potential as novel broad‐spectrum antibiotics or adjuvants that work with antibiotics to selectively allow passage across bacterial membranes.
The ligand‐binding domain of a chemoreceptor from Comamonas testosteroni has a previously unknown homotrimeric structure
Authors: Hong Yuan , Huang Zhou , Guo Lu , Ni Bin , Jiang Cheng‐Ying , Li Xiao‐Jing , Hou Yan‐Jie , Yang Wen‐Si , Wang Da‐Cheng , Zhulin Igor B. , Liu Shuang‐Jiang , Li De‐Feng 
Published: June 2019

SummaryTransmembrane chemoreceptors are widely present in Bacteria and Archaea. They play a critical role in sensing various signals outside and transmitting to the cell interior. Here, we report the structure of the periplasmic ligand‐binding domain (LBD) of the transmembrane chemoreceptor MCP2201, which governs chemotaxis to citrate and other organic compounds in Comamonas testosteroni. The apo‐form LBD crystal revealed a typical four‐helix bundle homodimer, similar to previously well‐studied chemoreceptors such as Tar and Tsr of Escherichia coli. However, the citrate‐bound LBD revealed a four‐helix bundle homotrimer that had not been observed in bacterial chemoreceptor LBDs. This homotrimer was further confirmed with size‐exclusion chromatography, analytical ultracentrifugation and cross‐linking experiments. The physiological importance of the homotrimer for chemotaxis was demonstrated with site‐directed mutations of key amino acid residues in C. testosteroni mutants.
Invasive aspergillosis in critically ill patients: An autopsy study
Authors: Tejerina Eva E. , Abril Elena , Padilla Rebeca , Rodríguez Ruíz Covadonga , Ballen Aida , Frutos‐Vivar Fernando , Lorente José Ángel , Esteban Andrés 
Published: June 2019

SummaryAutopsy studies show that IA is among the most commonly missed diagnoses in critically ill patients. And, because of lack of unequivocal diagnostic criteria, a timely diagnosis remains challenging. We investigate the epidemiology of and the clinical risk factors for IA in critically ill patients. We conducted a retrospective, observational study of all consecutive ICU patients with evidence of IA in the postmortem examination. During the period of the study (25 years), 893 postmortem examinations were performed in the ICU. Twenty‐five patients (2.8%) were diagnosed with IA in autopsy. Only ten (40%) were classified as IA ante‐mortem, based on the initiation of antifungal treatment. The most common comorbid conditions were corticosteroid treatment (n = 14, 56%), chronic obstructive pulmonary disease (COPD) (n = 11, 44%), immunosuppression (n = 6, 24%) and haematological malignancy (n = 5, 20%). Twenty‐three patients (92%) had three or more risk factors for IA. Critically ill patients with pulmonary infiltrates, treated with high doses intravenous corticosteroids (even for a short period of time), particularly COPD patients who developed worsening respiratory insufficiency despite appropriate treatment were at the highest risk of IA.
Does a tradeoff between trait plasticity and resource conservatism contribute to the maintenance of alternative stable states?
Authors: Power Simon C. , Verboom G. Anthony , Bond William J. , Cramer Michael D. 
Published: June 2019

Summary

Phenotypic plasticity facilitates species persistence across resource gradients but may be limited in low‐resource environments requiring resource conservation. We investigated the tradeoff between trait plasticity and resource conservatism across a biome boundary characterized by high turnover in nutrient and light availability, and whether this contributes to the maintenance of alternative stable states.

Differences in plasticity were determined by comparing species’ leaf and foliar nutritional trait responses to light, represented by leaf area index (LAI), and soil nutrient availability across forest–shrubland boundaries in South Africa.

Although forest had higher LAI and soil nutrient availability than shrubland, forest species experienced greater resource variation. With increasing LAI and nutrient availability, forest species increased their leaf size, specific leaf area and leaf area/stem length, and decreased their foliar [N] and [K]. Although these responses are indicative of plasticity, shrubland species appeared to lack plasticity as evidenced by limited trait variation with environmental heterogeneity.

Inhabiting diverse light environments imposed by forests probably selects for plasticity, whereas light‐saturated, fire‐prone, nutrient‐poor environments that select for conservative leaf traits and below‐ground investments compromise plasticity in shrubland species. This pattern suggests a tradeoff between trait plasticity and resource conservatism, which may support the stability of alternative vegetation states.
Determination of sialic acid levels by using surface‐enhanced Raman spectroscopy in periodontitis and gingivitis
Authors: Hernández‐Cedillo Alondra , García-Valdivieso Ma. Guadalupe , Hernández‐Arteaga Aida Catalina , Patiño-Marín Nuria , Vértiz-Hernández Ángel Antonio , José‐Yacamán Miguel , Navarro‐Contreras Hugo Ricardo 
Published: June 2019

AbstractObjectivesTo compare the sialic acid (SA) levels in saliva among periodontitis‐affected, gingivitis and control patients.MethodsThe study involved 93 subjects. The participants were divided into three groups: (1) 30 subjects without periodontal disease (control group); (2) 30 subjects with gingivitis; and (3) 33 subjects with periodontitis. The oral parameters examined were as follows: (a) Simplified Oral Hygiene Index; (b) Calculus Index; (c) Gingival Index; (d) probing pocket depth; and (e) level of epithelial attachment. SA levels in saliva were measured by means of surface‐enhanced Raman spectroscopy (SERS). This method has demonstrated the capacity to detect extremely low concentrations of molecules. The spectrum was calibrated using analytical reagent SA.ResultsThe obtained median values for SA concentrations were 5.98, 7.32, and 17.12 mg/dl for control, gingivitis, and periodontitis patients, respectively.ConclusionsOur measurements by SERS corroborate that in periodontitis‐affected patients, the SA concentration is larger than their concentrations in either control or gingivitis patients. This confirms previous reports and opens the possibility of using SERS as a diagnostic tool.
Effects of Streptococcus salivarius K12 with nystatin on oral candidiasis—RCT
Authors: Hu Lijun , Mao Qinghua , Zhou Peiru , Lv Xin , Hua Hong , Yan Zhimin 
Published: June 2019

AbstractObjectiveTo evaluate the efficacy and safety of Streptococcus salivarius K12 as an adjuvant in treating oral candidiasis.MethodsA total of 56 patients were participated in the randomized, double‐blinded, placebo‐controlled clinical trial. The S. salivarius K12 or placebo lozenges plus nystatin tablets were given for up to 4 weeks at 1‐week interval and then followed up for 1 week thereafter. We collected and analyzed the mycological and clinical data, treatment course, and safety data.ResultsAt the end of the treatment, significant differences were found in the mycological cure rates between K12 group and control group (90.48% and 55.56%, respectively, p = 0.008). Survival analysis demonstrated no statistical difference in overall cure rates comprehensively considering mycological cure, clinical improvement, and recurrence (p = 0.078), while statistical difference was found in mycological cure (p = 0.013) between the two groups. The median treatment courses of K12 group and control group were 3 weeks and 4 weeks, respectively. No severe events were reported during the study.ConclusionStreptococcus salivarius K12 exhibited potential efficacy and safety as an adjuvant in treating oral candidiasis by enhancing mycological cure and shortening the treatment course of conventional antifungal therapy in this randomized, double‐blinded, placebo‐controlled clinical trial. Further large‐scale clinical studies are desired to accumulate more evidence for its clinical applications.