bluuebunny/crossref_metadata_2025 huggingface dataset:
Statin use associated with lower risk of epilepsy after intracranial haemorrhage: A population‐based cohort study
Authors: Lin Hung‐Wei , Ho Yunn‐Fang , Lin Fang‐Ju
Published: May 2018

Aims

To examine the association between statin use before and after intracranial haemorrhage (ICH) and the risk of poststroke epilepsy (PSE).

Methods

Patients with new‐onset ICH between 2004 and 2012 were identified from the Taiwan National Health Insurance Research Database. The main outcome was the occurrence of epilepsy after stroke. Multivariable Cox regression modelling was used to estimate the association between statin use and the risk of PSE, with poststroke medication exposures being treated as time‐dependent variables.

Results

A total of 7435 patients with ICH were enrolled with a median follow‐up of 17.6 months. Within the study cohort, 709 patients developed PSE. Poststroke, but not prestroke, stain use was associated with a reduced risk of PSE (adjusted hazard ratio 0.62, 95% confidence interval 0.42–0.90, P = 0.01). In subanalyses, a trend of a dose–response relationship was observed. A significant PSE risk reduction was correlated with a higher cumulative statin dose. Moreover, the risk of PSE was lower in patients receiving moderate‐to‐high‐intensity statin therapy (adjusted hazard ratio 0.37, 95% confidence interval 0.18–0.75, P = 0.01). Lipophilic and hydrophilic statins were similar with regard to their associations with the reduced risk of PSE.

Conclusions

Statin therapy may reduce the risk of PSE after ICH, especially with moderate‐to‐high therapy intensity. Further research is needed to understand the mechanisms underlying the potential protective effects of statins against PSE in this patient population.
Identifying ranching landscape values in the Calgary, Alberta region: Implications for land‐use planning
Authors: Benoit Aimee , Johnston Tom , MacLachlan Ian , Ramsey Doug
Published: May 2018

In recent years, ranching landscapes in the region of Calgary, Alberta have experienced intensifying land‐use pressures related to urban growth and development. At the same time, Alberta's land‐use policies have introduced voluntary, market‐based incentives to encourage the conservation and stewardship of private land. Given this new emphasis, this study aims to better understand different perspectives of ranching landscapes among residents and landowners in two rural municipalities surrounding Calgary. Drawing on cultural landscapes and political ecology literatures, this paper identifies four broad categories of ranching landscape values that participants felt were important to maintain: lifestyle and community values; ecological values; production values; and economic values and property rights. Participants’ diverse place meanings suggest a need to expand the ways in which landscapes are understood and assessed within local contexts, as a strategy for promoting private land stewardship and for resolving tensions in land‐use planning processes.
Non‐small cell lung carcinoma metastatic cells in a pericardial effusion
Authors: Gérard D. , Thomas B. , Lesesve J.‐F.
Published: May 2018

Lung carcinoma can rarely present initially with a pericardial effusion. We describe a case with clearly illustrated images to emphasise that this situation can be encountered in everyday cytology practice.
Ecological correlates of mammal β‐diversity in Amazonian land‐bridge islands: from small‐ to large‐bodied species
Authors: Palmeirim Ana Filipa , Benchimol Maíra , Morante‐Filho José Carlos , Vieira Marcus Vinícius , Peres Carlos A.
Published: May 2018

Aim

Mega hydroelectric dams have become one of the main drivers of biodiversity loss in the lowland tropics. In these reservoirs, vertebrate studies have focused on local (α) diversity measures, whereas between‐site (β) diversity remains poorly assessed despite its pivotal importance in understanding how species diversity is structured and maintained. Here, we unravel the patterns and ecological correlates of mammal β‐diversity, including both small (SM) and midsized to large mammal species (LM) across 23 islands and two continuous forest sites within a mega hydroelectric reservoir.

Location

Balbina Hydroelectric Dam, Central Brazilian Amazonia.

Methods

Small mammals were sampled using live and pitfall traps (48,350 trap‐nights), and larger mammals using camera traps (8,160 trap‐nights). β‐diversity was examined for each group using multiplicative diversity decomposition of Hill numbers, which considers the importance of rare, common and dominant species, and tested to what extent those were related to a set of environmental characteristics measured at different spatial scales.

Results

β‐diversity for both mammal groups was higher when considering species presence–absence. When considering species abundance, β‐diversity was significantly higher for SM than for LM assemblages. Habitat variables, such as differences in tree species richness and percentage of old‐growth trees, were strong correlates of β‐diversity for both SMs and LMs. Conversely, β‐diversity was weakly related to patch and landscape characteristics, except for LMs, for which β‐diversity was correlated with differences in island sizes.

Main conclusions

The lower β‐diversity of LMs between smaller islands suggests subtractive homogenization of this group. Although island size plays a major role in structuring mammal α‐diversity in several land‐bridge islands, local vegetation characteristics were additional key factors determining β‐diversity for both mammal groups. Maintaining the integrity of vegetation characteristics and preventing the formation of a large set of small islands within reservoirs should be considered in long‐term management plans in both existing and planned hydropower development in lowland tropical forests.
Immigrant and native? The case of the swamp foxtail Cenchrus purpurascens in Australia
Authors: Toon A. , Sacre E. , Fensham R. J. , Cook L. G.
Published: May 2018

Aim

Spring wetlands in arid regions of Australia provide habitat for many highly endemic organisms, including fish, molluscs, crustaceans and plants, but these unique ecosystems have been under pressure since the arrival of Europeans about 250 years ago. Arguments over whether particular plant species are long‐term spring inhabitants or recent immigrants are confounding efforts to conserve spring flora. One such example is the swamp foxtail, Cenchrus purpurascens, a grass that is variably listed in the literature as being native to Australian wetlands or as being an introduced weedy species from Asia.

Location

Australia, China and Korea.

Methods

We use DNA sequences of the nuclear ITS and the chloroplast DNA regions trnL‐F and matK, complemented with newly designed simple sequence repeat (SSR) markers, to assess the native status of C. purpurascens in Australia and determine whether there is genetic differentiation among spring populations.

Results

We find that, although there has been gene flow between Asia and Australia in the geological past, the populations are now strongly differentiated: C. purpurascens has probably been present in Australia through the Pleistocene. In Australia, there is also strong genetic differentiation among populations from different springs, and between springs and non‐springs populations, indicating long‐term occupancy of some springs sites.

Main conclusions

Cenchrus purpurascens was present in Australia well before European colonization of the continent. The level of genetic differentiation among populations enhances the existing conservation values of Elizabeth Springs, Edgbaston, Doongmabulla and Carnarvon Gorge springs complexes within the Great Artesian Basin.
Photobiomodulation with red light‐emitting diodes accelerates hepatocyte proliferation through reactive oxygen species/extracellular signal‐regulated kinase pathway
Authors: Feng Rui , Morine Yuji , Ikemoto Tetsuya , Imura Satoru , Iwahashi Shuichi , Saito Yu , Shimada Mitsuo
Published: May 2018

Aim

Cell‐based transplantation is an alternate method of liver transplantation to delay the onset of end‐stage liver diseases. For successful treatment, cells need to be expended in vitro expeditiously. However, autogenetic hepatocytes as the ideal cell source for therapy remain in quiescence so proliferation is rare. Photobiomodulation therapy has been used to stimulate some kinds of cell proliferation, but is unknown whether red light‐emitting diode (LED) irradiation can promote primary hepatocyte proliferation. The aim of this study was to evaluate the effect of red LED irradiation on hepatocytes in vitro.

Methods

Mouse primary hepatocytes were isolated and received red LED treatment. The cell viability, reactive oxygen species (ROS) levels, phosphorylated extracellular signal‐regulated kinase1/2 (pERK1/2) and some cell cycle‐related proteins were observed. Additionally, ROS inhibition and pERK1/2 inhibition were carried out to determine the effect of ROS and ERK1/2 in red LED irradiation.

Results

The red LED irradiation increased hepatocyte proliferation, elevated intracellular ROS levels, and stimulated ERK1/2 activation and cell cycle‐related gene expression. The mitosis promoting effect of red LED irradiation could be disturbed by ROS or pERK inhibition. The red LED irradiation promoted hepatocyte proliferation through the ROS/pERK1/2 pathway.

Conclusions

Red LED irradiation could accelerate hepatocyte proliferation through the ROS/pERK1/2 pathway. Red LED irradiation might be a potential method to increase hepatocyte cell numbers in vitro and support cell‐based transplantation in clinical work.
Extracellular vesicles: Toward a clinical application in urological cancer treatment
Authors: Urabe Fumihiko , Kosaka Nobuyoshi , Kimura Takahiro , Egawa Shin , Ochiya Takahiro
Published: May 2018

Extracellular vesicles are nanometer‐sized lipid membranous vesicles that are released from almost all types of cells into the extracellular space. Extracellular vesicles have gained considerable attention in the past decade, and emerging evidence suggests that they play novel roles in mediating cancer biology. Extracellular vesicles contain pathogenic components, such as proteins, DNA fragments, messenger ribonucleic acids, non‐coding ribonucleic acids and lipids, all of which mediate paracrine signaling in the tumor microenvironment. Extracellular vesicles impact the multistep process of cancer progression through modulation of the immune system, angiogenesis and pre‐metastatic niche formation through transfer of their contents. Therefore, a better understanding of their roles in urological cancers will provide opportunities for novel therapeutic strategies. In addition, the contents of extracellular vesicles hold promise for the discovery of liquid‐based biomarkers for prostate, kidney and bladder cancers. Here, we summarize the current research regarding extracellular vesicles in urological cancer and discuss potential clinical applications for extracellular vesicles in urological cancer.
Partial flocculation for spray drying of spherical mixed metal oxide particles
Authors: Ehrhart Brian D. , Ward Barbara J. , Richardson Benjamin M. , Anseth Kristi S. , Weimer Alan W.
Published: May 2018

Particles are an important design consideration for many proposed solar thermochemical water splitting reactor concepts. These particles must maintain physical integrity and chemical performance at very high temperatures (>900°C) while flowing within a system. Spray drying is a commonly used, scalable method to produce solid spherical particles that have the best opportunity to meet these requirements. Spray drying is used to produce hercynite (FeAl2O4) particles using pH‐modification of a charge‐stabilized sol. This process involves inducing partial flocculation in nanoparticle suspensions to yield larger particles that are spherical and structurally robust. A commercial boehmite suspension is characterized along with a mixture of the boehmite suspension with an iron oxide suspension. Zeta potential near zero and peak yield stress measurements at the same pH indicate flocculation, but associated sedimentation behavior is not observed. The behavior of both the boehmite‐only and mixed suspensions both seem to be driven by the behavior of the boehmite suspension alone. Spray dried particles from the mixed suspension at the critical pH gave significantly larger and more spherical particles, which also indicates flocculation. This relatively simple technique shows promise for new mixed‐metal material formulations and scalable applications.
Excavating New Constructs for Family Stress Theories in the Context of Everyday Life Experiences of Black American Families
Authors: Murry Velma McBride , Butler‐Barnes Sheretta T. , Mayo‐Gamble Tilicia L. , Inniss‐Thompson Misha N.
Published: May 2018

Much of what happens inside Black families involves spillover effects and consequences of macro‐level stressors. Racism is a major stressor that cascades through Black families' lives, with detrimental consequences for their everyday life experiences. To understand ways in which Black families successfully navigate social, environment, and cultural pressures and constraints, we sought to gain insight into these processes by conducting a systematic, deep excavation, in order to (a) critically examine the adequacy and accuracy of traditional frameworks used to study stress in Black American families, (b) determine whether the studies of stress in Black families in the era of the first Black family in the White House stimulated new areas of research, and (c) advance the field of stress research in general and for Black Americans, in particular, by proposing a heuristic model anchored in a historical, contextual, life‐span perspective, with emphasis on culturally specific strengths‐based coping adaptation.
The Cultural Lens Approach to Bowen Family Systems Theory: Contributions of Family Change Theory
Authors: Erdem Gizem , Safi Ommay Aiman
Published: May 2018

An accumulation of theoretical and empirical work focuses on expanding Bowen family systems theory (BFST) to be more culturally expansive by including gender, ethnicity, race, social class, and sexual orientation, as well as family history, values, and rituals. In the current article, we contribute to the discussion of culture in BFST and move the question of diversity from how family processes are different to why they are different. Utilizing Hardin and colleagues' cultural lens approach, we discuss the cultural validity of BFST, more specifically the concept of differentiation of self and its premises, in five steps. Further, we propose the integration of Kağıtçıbaşı's family change theory and Carter and McGoldrick's multicultural perspective with BFST and offer cultural examples. Potential contributions and limitations of the cultural lens approach in expanding our understanding BFST are discussed, as are implications for research and clinical practice.
Integrating Life Course, Globalization, and the Study of Racial and Ethnic Families
Authors: Trask Bahira Sherif
Published: May 2018

Despite the proliferation of studies that specifically employ life course perspectives for contemporary families, an important omission, with only a few exceptions, has been critical inquiry into how race, ethnicity, cultural diversity, and global processes affect individual and family development. Furthermore, this perspective has been seriously underutilized for understanding the diversity of human experiences in global contexts. A focus on these issues should help move the study of families away from the inherent ethnocentric lens that undergirds so much of the discipline. The life course perspective, with its focus on the interplay of micro and macro factors, is a critical theoretical tool in expanding our understanding of context, vantage point, pluralism, and power relationships. New approaches to understanding and incorporating a life course perspective may spur fresh pathways for researchers and policy makers as they attempt to make sense of complex social phenomena.
Toward a Better Understanding of African American Families: Development of the Sociocultural Family Stress Model
Authors: McNeil Smith Shardé , Landor Antoinette M.
Published: May 2018

Family stress models have a long and rich history in family science research and are useful frameworks for understanding multicultural families. Although these models add greatly to research on diverse families in general, we believe that the almost exclusive focus on cross‐cultural replications may come at the cost of a more culturally and contextually informed understanding of specific groups such as African Americans. In this article, we expand current family stress models using two key extensions that challenge some of the underlying assumptions and situate constructs within intersectionality and mundane extreme environmental stress (MEES) perspectives. In addition, we introduce an integrative theoretical framework, the sociocultural family stress (SFS) model, which includes explicit considerations of both the culture and heterogeneity of African Americans and their families. Suggestions for future research are discussed.
Terpenes associated with resistance against the gall wasp, Leptocybe invasa, in Eucalyptus grandis
Authors: Naidoo Sanushka , Christie Nanette , Acosta Juan J. , Mphahlele Makobatjatji M. , Payn Kitt G. , Myburg Alexander A. , Külheim Carsten
Published: May 2018

Leptocybe invasa is an insect pest causing gall formation on oviposited shoot tips and leaves of Eucalyptus trees leading to leaf deformation, stunting, and death in severe cases. We previously observed different constitutive and induced terpenes, plant specialized metabolites that may act as attractants or repellents to insects, in a resistant and susceptible clone of Eucalyptus challenged with L. invasa. We tested the hypothesis that specific terpenes are associated with pest resistance in a Eucalyptus grandis half‐sib population. Insect damage was scored over 2 infestation cycles, and leaves were harvested for near‐infrared reflectance (NIR) and terpene measurements. We used Bayesian model averaging for terpene selection and obtained partial least squares NIR models to predict terpene content and L. invasa infestation damage. In our optimal model, 29% of the phenotypic variation could be explained by 7 terpenes, and the monoterpene combination, limonene, α‐terpineol, and 1,8‐cineole, could be predicted with an NIR prediction ability of  .67. Bayesian model averaging supported α‐pinene, γ‐terpinene, and iso‐pinocarveol as important for predicting L. invasa infestation. Susceptibility was associated with increased γ‐terpinene and α‐pinene, which may act as a pest attractant, whereas reduced susceptibility was associated with iso‐pinocarveol, which may act to recruit parasitoids or have direct toxic effects.
Nematodes network too: diversity, abundance and dispersal via plant produce trade networks
Authors: Banks N. C. , Tangchitsomkid N. , Chanmalee T. , Sangsawang T. , Songvilay P. , Phannamvong N. , Thamakhot S. , Paini D. R. , Bayliss K. L. , Hodda M. E.
Published: May 2018

The dispersal of invasive species, such as plant pests, can have major economic, environmental and social impacts worldwide. Movement of plant pests from farms to both foreign and domestic markets is facilitated by trade networks, such as plant produce trade networks. While many potential pathways of invasive plant pest entry are regulated, few studies have examined the diversity, abundance and dispersal of soil microorganisms, such as nematodes, on plant produce while en route between origin and destination to quantify the risk of invasive plant pest introductions via these pathways. Here it is shown that a large range and number of live nematodes are dispersing locally and nationally via plant produce trade networks, with the potential to also move internationally. Up to 98% of samples tested carried free‐living nematodes and up to 40% carried plant‐parasitic forms. Diversity of nematodes varied between countries and regions, and numbers on samples generally decreased with increasing distance from the farm to market. These findings may have implications for plant biosecurity surveillance as well as human health. Moreover, nematodes provide a model for other potentially invasive species dispersing via plant produce trade networks.
The Derivative Yajima–Oikawa System: Bright, Dark Soliton and Breather Solutions
Authors: Chen Junchao , Feng Bao‐Feng , Maruno Ken‐ichi , Ohta Yasuhiro
Published: May 2018

In this paper, we study the derivative Yajima–Oikawa (YO) system which describes the interaction between long and short waves (SWs). It is shown that the derivative YO system is classified into three types which are similar to the ones of the derivative nonlinear Schrödinger equation. The general N‐bright and N‐dark soliton solutions in terms of Gram determinants are derived by the combination of the Hirota's bilinear method and the Kadomtsev–Petviashvili hierarchy reduction method. Particularly, it is found that for the dark soliton solution of the SW component, the magnitude of soliton can be larger than the nonzero background for some parameters, which is usually called anti‐dark soliton. The asymptotic analysis of two‐soliton solutions shows that for both kinds of soliton only elastic collision exists and each soliton results in phase shifts in the long and SWs. In addition, we derive two types of breather solutions from the different reduction, which contain the homoclinic orbit and Kuznetsov–Ma breather solutions as special cases. Moreover, we propose a new (2+1)‐dimensional derivative Yajima–Oikawa system and present its soliton and breather solutions.
The real peso–dollar rate and US–Mexico industry trade: an asymmetric analysis
Authors: Bahmani‐Oskooee Mohsen , Harvey Hanafiah , Hegerty Scott W.
Published: May 2018

In an attempt to improve upon previous analyses and find further evidence for exchange rate theories such as the ‘J‐curve', numerous studies have introduced novel econometric approaches that might help uncover significant results through disaggregation and nonlinearity. This study applies the nonlinear cointegration method of Shin et al. () to US–Mexican trade balances in 91 individual industries. While the linear model yields support for the ‘J‐curve' effect in 16 industries, the nonlinear model raises this number to 29 which includes the two largest industries that engage in 35% of the trade between two countries. Furthermore, while the short‐run asymmetric effects of exchange rate changes were discovered in almost all industries, short‐run effects translated to significant long‐run asymmetric effects in 52 industries.
The Effect of Body Composition and Physical Fitness Factors on Performance Prediction of Elite Male Trampolines
Authors: Uçan Izzet
Published: May 2018

The main purpose of this study was the effect of body composition and physical fitness factors on performance prediction of elite male trampolines. So, 45 male athletes, who participated in the national trampoline team's preparation camps for participation at the 2014 Asian Games in four age categories included Children, Juniors, Adolescents and Seniors were selected using targeted sampling as subjects. Variables of study included 24 body composition indices and 20 physical fitness factors which were measured using standard procedures and instruments. Data were analyzed using Pearson correlation coefficient and multiple regression models at the 0.05 significance level. Results of study showed that, the relationships of the shoulder belt muscle strength (r=0.294) with performance are statistically significant and in other cases, there was no significant relationships (p>0.05). Results of study showed the relationships of the shoulder belt muscle strength (r=0.294), aerobic power (r=0.351), relative minimum anaerobic power (r=0.256), with performance are statistically significant.and in other cases, observed relationships were not statistically significant (p>0.05). Findings of this study suggest that, in the high competitive level of trampoline body composition indices do not have predictive role in preparation programs of elite male trampolines, but physical factors have predictive role in preparation programs of elite male trampolines.
The Performance Prediction of Elite Male Trampolines Based on Physical Fitness Factors
Authors: Uçan Izzet
Published: May 2018

The main purpose of this study was prediction of elite male trampolines performance based on the selected physical capabilities in different age categories. To this aim, 45 male athletes (age 14.17±2.86 yrs, athletic experience 7.22±3.64 yrs and competitive experience 3.31±2.44 yrs), who participated in the national trampoline team's preparation camps for participation at the 2014 Asian Games in four age categories included children (ages 11 and 12 yrs), juniors (ages 13 and 14 yrs), adolescents (ages 15 to 17 yrs), and seniors (ages 18 yrs <), were selected using targeted sampling. Variables of study included 20 physical fitness factors which were measured using standard procedures and instruments. Data were analyzed using Pearson correlation coefficient and multiple regression models at the 0.05 significance level. Results of study showed that only the relationships of the shoulder belt muscle strength (r=0.294), aerobic power (r=0.351), relative minimum anaerobic power (r=0.256), with performance are statistically significant and in other cases, observed relationships were not statistically significant (p>0.05). Findings of this study suggest that, in the high competitive level of trampoline, physical factors have predictive role in preparation programs of elite male trampolines.
The force and stiffness of myosin motors in the isometric twitch of a cardiac trabecula and the effect of the extracellular calcium concentration
Authors: Pinzauti Francesca , Pertici Irene , Reconditi Massimo , Narayanan Theyencheri , Stienen Ger J. M. , Piazzesi Gabriella , Lombardi Vincenzo , Linari Marco , Caremani Marco
Published: May 2018

Key points

Fast sarcomere‐level mechanics in intact trabeculae, which allows the definition of the mechano‐kinetic properties of cardiac myosin in situ, is a fundamental tool not only for understanding the molecular mechanisms of heart performance and regulation, but also for investigating the mechanisms of the cardiomyopathy‐causing mutations in the myosin and testing small molecules for therapeutic interventions.

The approach has been applied to measure the stiffness and force of the myosin motor and the fraction of motors attached during isometric twitches of electrically paced trabeculae under different extracellular Ca2+ concentrations.

Although the average force of the cardiac myosin motor (∼6 pN) is similar to that of the fast myosin isoform of skeletal muscle, the stiffness (1.07 pN nm–1) is 2‐ to 3‐fold smaller.

The increase in the twitch force developed in the presence of larger extracellular Ca2+ concentrations is fully accounted for by a proportional increase in the number of attached motors.

The mechano‐kinetic properties of the cardiac myosin were studied in situ, in trabeculae dissected from the right ventricle of the rat heart, by measuring the stiffness of the half‐sarcomere both at the twitch force peak (Tp) of an electrically paced intact trabecula at different extracellular Ca2+ concentrations ([Ca2+]o), and in the same trabecula after skinning and induction of rigor. Taking into account the contribution of filament compliance to half‐sarcomere compliance and the lattice geometry, we found that the stiffness of the cardiac myosin motor is 1.07 ± 0.09 pN nm–1, which is slightly larger than that of the slow myosin isoform of skeletal muscle (0.6‐0.8 pN nm–1) and 2‐ to 3‐fold smaller than that of the fast skeletal muscle isoform. The increase in Tp from 61 ± 4 kPa to 93 ± 9 kPa, induced by raising [Ca2+]o from 1 to 2.5 mm at sarcomere length ∼2.2 μm, is accompanied by an increase of the half‐sarcomere stiffness that is explained by an increase of the fraction of actin‐attached motors from 0.08 ± 0.01 to 0.12 ± 0.02, proportional to Tp. Consequently, each myosin motor bears an average force of 6.14 ± 0.52 pN independently of Tp and [Ca2+]o. The application of fast sarcomere‐level mechanics to intact trabeculae to define the mechano‐kinetic properties of the cardiac myosin in situ represents a powerful tool for investigating cardiomyopathy‐causing mutations in the myosin motor and testing specific therapeutic interventions.
Emergence of High-Level Colistin Resistance in an Acinetobacter baumannii Clinical Isolate Mediated by Inactivation of the Global Regulator H-NS
Authors: Deveson Lucas Deanna , Crane Bethany , Wright Amy , Han Mei-Ling , Moffatt Jennifer , Bulach Dieter , Gladman Simon L. , Powell David , Aranda Jesus , Seemann Torsten , Machado Diana , Pacheco Teresa , Marques Teresa , Viveiros Miguel , Nation Roger , Li Jian , Harper Marina , Boyce John D.
Published: May 2018

Colistin is a crucial last-line drug used for the treatment of life-threatening infections caused by multidrug-resistant strains of the Gram-negative bacterium
Acinetobacter baumannii
. However, colistin-resistant
A. baumannii
isolates can still be isolated following failed colistin therapy. Resistance is most often mediated by the addition of phosphoethanolamine (pEtN) to lipid A by PmrC, following missense mutations in the
pmrCAB
operon encoding PmrC and the two-component signal transduction system PmrA/PmrB. We recovered a pair of
A. baumannii
isolates from a single patient before (6009-1) and after (6009-2) failed colistin treatment. These strains displayed low and very high levels of colistin resistance (MICs, 8 to 16 μg/ml and 128 μg/ml), respectively. To understand how increased colistin resistance arose, we sequenced the genome of each isolate, which revealed that 6009-2 had an extra copy of the insertion sequence element IS
Aba125
within a gene encoding an H-NS family transcriptional regulator. To confirm the role of H-NS in colistin resistance, we generated an
hns
deletion mutant in 6009-1 and showed that colistin resistance increased upon the deletion of
hns
. We also provided 6009-2 with an intact copy of
hns
and showed that the strain was no longer resistant to high concentrations of colistin. Transcriptomic analysis of the clinical isolates identified more than 150 genes as being differentially expressed in the colistin-resistant
hns
mutant 6009-2. Importantly, the expression of
eptA
, encoding a second lipid A-specific pEtN transferase but not
pmrC
, was increased in the
hns
mutant. This is the first time an H-NS family transcriptional regulator has been associated with a pEtN transferase and colistin resistance.
Terminal Olefin Profiles and Phylogenetic Analyses of Olefin Synthases of Diverse Cyanobacterial Species
Authors: Zhu Tao , Scalvenzi Thibault , Sassoon Nathalie , Lu Xuefeng , Gugger Muriel
Published: May 2018

Cyanobacteria can synthesize alkanes and alkenes, which are considered to be infrastructure-compatible biofuels. In terms of physiological function, cyanobacterial hydrocarbons are thought to be essential for membrane flexibility for cell division, size, and growth. The genetic basis for the biosynthesis of terminal olefins (1-alkenes) is a modular type I polyketide synthase (PKS) termed olefin synthase (Ols). The modular architectures of Ols and structural characteristics of alkenes have been investigated only in a few species of the small percentage (approximately 10%) of cyanobacteria that harbor putative Ols pathways. In this study, investigations of the domains, modular architectures, and phylogenies of Ols in 28 cyanobacterial strains suggested distinctive pathway evolution. Structural feature analyses revealed 1-alkenes with three carbon chain lengths (C
15
, C
17
, and C
19
). In addition, the total cellular fatty acid profile revealed the diversity of the carbon chain lengths, while the fatty acid feeding assay indicated substrate carbon chain length specificity of cyanobacterial Ols enzymes. Finally,
in silico
analyses suggested that the N terminus of the modular Ols enzyme exhibited characteristics typical of a fatty acyl-adenylate ligase (FAAL), suggesting a mechanism of fatty acid activation via the formation of acyl-adenylates. Our results shed new light on the diversity of cyanobacterial terminal olefins and a mechanism for substrate activation in the biosynthesis of these olefins.

IMPORTANCE
Cyanobacterial terminal olefins are hydrocarbons with promising applications as advanced biofuels. Despite the basic understanding of the genetic basis of olefin biosynthesis, the structural diversity and phylogeny of the key modular olefin synthase (Ols) have been poorly explored. An overview of the chemical structural traits of terminal olefins in cyanobacteria is provided in this study. In addition, we demonstrated by
in vivo
fatty acid feeding assays that cyanobacterial Ols enzymes might exhibit substrate carbon chain length specificity. Furthermore, by performing bioinformatic analyses, we observed that the substrate activation domain of Ols exhibited features typical of a fatty acyl-adenylate ligase (FAAL), which activates fatty acids by converting them to fatty acyl-adenylates. Our results provide further insight into the chemical structures of terminal olefins and further elucidate the mechanism of substrate activation for terminal olefin biosynthesis in cyanobacteria.
Susceptibility of Methicillin-Resistant and -Susceptible Staphylococcus aureus Isolates of Various Clonal Lineages from Germany to Eight Biocides
Authors: Kernberger-Fischer Isa Adriana , Krischek Carsten , Strommenger Birgit , Fiegen Ulrike , Beyerbach Martin , Kreienbrock Lothar , Klein Günter , Kehrenberg Corinna
Published: May 2018

Few studies have been conducted on the susceptibility of bacteria to biocides. A total of 182 methicillin-resistant and -susceptible
Staphylococcus aureus
isolates collected from healthy or diseased humans and animals in Germany were included in the present study. Sixty-three isolates of animal origin and 119 human isolates were tested for their MICs to eight biocides or heavy metals by the broth microdilution method. The MIC
50
and MIC
90
values of human and animal isolates were equal or differed by not more than 1 dilution step, and statistical analysis revealed that differences between MICs of human and animal isolates were not significant. However, when taking into account the multilocus sequence type (MLST), a strong tendency (
P
= 0.054) to higher MICs of silver nitrate was detected for clonal complex 398 (CC398) isolates from humans compared to those from animals. Furthermore, a comparison of MIC values from isolates belonging to different clonal lineages revealed that important human lineages such as CC22 and CC5 exhibited significantly (
P
< 0.05) higher MICs for the biocides chlorhexidine, benzethonium chloride, and acriflavine than the main animal lineage sequence type 398 (ST398). Isolates with elevated MIC values were tested for the presence of biocide and heavy metal tolerance-mediating genes by PCR assays, and the following genes were detected:
mepA
(
n
[no. of isolates containing the gene] = 44),
lmrS
(
n
= 36),
norA
(
n
= 35),
sepA
(
n
= 22),
mco
(
n
= 5),
czrC
(
n
= 3),
smr
(
n
= 2),
copA
(
n
= 1),
qacA
and/or -
B
(
n
= 1),
qacG
(
n
= 2), and
qacJ
(
n
= 1). However, only for some compounds was a correlation between the presence of a biocide tolerance gene and the level of MIC values detected.

IMPORTANCE
Biocides play an essential role in controlling the growth of microorganisms and the dissemination of nosocomial pathogens. In this study, we determined the susceptibility of methicillin-resistant and -susceptible
S. aureus
isolates from humans and animals to various biocides and heavy metal ions and analyzed differences in susceptibilities between important clonal lineages. In addition, the presence of biocide or heavy metal tolerance-mediating genes was investigated. We demonstrated that important human lineages such as CC22 and CC5 had significantly higher MIC values for chlorhexidine, benzethonium chloride, and acriflavine than the main farm animal lineage, ST398. In addition, it was shown that for some combinations of biocides and tolerance genes, significantly higher MICs were detected for carriers. These findings provide new insights into
S. aureus
biocide and heavy metal tolerance.
Laboratory Activity Using Accessible Microfluidics to Study Nematode Behavior in an Electrical Field
Authors: Clawson Elizabeth D. , Blair Val , Nepper Julia F. , Stilwell Matthew D. , Tangen Travis , Weibel Douglas B.
Published: May 2018

Microfluidic devices are used in a broad range of technological applications, from creating ingredients for cosmetics to discovering new medicines. The small size of microfluidic channels makes it possible to isolate individual cells, collections of cells, and multicellular organisms and study their biology, ecology, and behavior. Microfluidics is particularly well suited to teaching students concepts from different fields of science. A challenge with conventional microfluidic devices is that they are difficult and expensive to make, which has been a barrier for their entry into curricula and classrooms. We describe a simple and low-cost method for creating microfluidic devices and use them to study the behavior of nematodes in an electrical field. Nematodes are ecologically and agriculturally important organisms that respond robustly to various environmental cues. In this activity, we demonstrate that nematodes swim through liquid in microfluidic channels in response to an applied electric field and describe student responses to this activity.
Conductive Particles Enable Syntrophic Acetate Oxidation between
Geobacter
and
Methanosarcina
from Coastal Sediments
Authors: Rotaru Amelia-Elena , Calabrese Federica , Stryhanyuk Hryhoriy , Musat Florin , Shrestha Pravin Malla , Weber Hannah Sophia , Snoeyenbos-West Oona L. O. , Hall Per O. J. , Richnow Hans H. , Musat Niculina , Thamdrup Bo
Published: May 2018

Coastal sediments are rich in conductive particles, possibly affecting microbial processes for which acetate is a central intermediate. In the methanogenic zone, acetate is consumed by methanogens and/or syntrophic acetate-oxidizing (SAO) consortia. SAO consortia live under extreme thermodynamic pressure, and their survival depends on successful partnership. Here, we demonstrate that conductive particles enable the partnership between SAO bacteria (i.e.,
Geobacter
spp.) and methanogens (
Methanosarcina
spp.) from the coastal sediments of the Bothnian Bay of the Baltic Sea. Baltic methanogenic sediments were rich in conductive minerals, had an apparent isotopic fractionation characteristic of CO
2
-reductive methanogenesis, and were inhabited by
Geobacter
and
Methanosarcina
. As long as conductive particles were delivered,
Geobacter
and
Methanosarcina
persisted, whereas exclusion of conductive particles led to the extinction of
Geobacter
. Baltic
Geobacter
did not establish a direct electric contact with
Methanosarcina
, necessitating conductive particles as electrical conduits. Within SAO consortia,
Geobacter
was an efficient [
13
C]acetate utilizer, accounting for 82% of the assimilation and 27% of the breakdown of acetate.
Geobacter
benefits from the association with the methanogen, because in the absence of an electron acceptor it can use
Methanosarcina
as a terminal electron sink. Consequently, inhibition of methanogenesis constrained the SAO activity of
Geobacter
as well. A potential benefit for
Methanosarcina
partnering with
Geobacter
is that together they competitively exclude acetoclastic methanogens like
Methanothrix
from an environment rich in conductive particles. Conductive particle-mediated SAO could explain the abundance of acetate oxidizers like
Geobacter
in the methanogenic zone of sediments where no electron acceptors other than CO
2
are available.

IMPORTANCE
Acetate-oxidizing bacteria are known to thrive in mutualistic consortia in which H
2
or formate is shuttled to a methane-producing
Archaea
partner. Here, we discovered that such bacteria could instead transfer electrons via conductive minerals. Mineral SAO (syntrophic acetate oxidation) could be a vital pathway for CO
2
-reductive methanogenesis in the environment, especially in sediments rich in conductive minerals. Mineral-facilitated SAO is therefore of potential importance for both iron and methane cycles in sediments and soils. Additionally, our observations imply that agricultural runoff or amendments with conductive chars could trigger a significant increase in methane emissions.
Hacking the Cell: Network Intrusion and Exploitation by Adenovirus E1A
Authors: King Cason R. , Zhang Ali , Tessier Tanner M. , Gameiro Steven F. , Mymryk Joe S.
Published: May 2018

As obligate intracellular parasites, viruses are dependent on their infected hosts for survival. Consequently, viruses are under enormous selective pressure to utilize available cellular components and processes to their own advantage. As most, if not all, cellular activities are regulated at some level via protein interactions, host protein interaction networks are particularly vulnerable to viral exploitation. Indeed, viral proteins frequently target highly connected “hub” proteins to “hack” the cellular network, defining the molecular basis for viral control over the host. This widespread and successful strategy of network intrusion and exploitation has evolved convergently among numerous genetically distinct viruses as a result of the endless evolutionary arms race between pathogens and hosts. Here we examine the means by which a particularly well-connected viral hub protein, human adenovirus E1A, compromises and exploits the vulnerabilities of eukaryotic protein interaction networks. Importantly, these interactions identify critical regulatory hubs in the human proteome and help define the molecular basis of their function.
An Attenuated CRISPR-Cas System in Enterococcus faecalis Permits DNA Acquisition
Authors: Hullahalli Karthik , Rodrigues Marinelle , Nguyen Uyen Thy , Palmer Kelli
Published: May 2018

Antibiotic-resistant bacteria are critical public health concerns. Among the prime causative factors for the spread of antibiotic resistance is horizontal gene transfer (HGT). A useful model organism for investigating the relationship between HGT and antibiotic resistance is the opportunistic pathogen
Enterococcus faecalis
, since the species possesses highly conjugative plasmids that readily disseminate antibiotic resistance genes and virulence factors in nature. Unlike many commensal
E. faecalis
strains, the genomes of multidrug-resistant (MDR)
E. faecalis
clinical isolates are enriched for mobile genetic elements (MGEs) and lack
c
lustered
r
egularly
i
nterspaced
s
hort
p
alindromic
r
epeats (CRISPR) and
C
RISPR-
as
sociated protein (Cas) genome defense systems. CRISPR-Cas systems cleave foreign DNA in a programmable, sequence-specific manner and are disadvantageous for MGE-derived genome expansion. An unexplored facet of CRISPR biology in
E. faecalis
is that MGEs that are targeted by native CRISPR-Cas systems can be maintained transiently. Here, we investigate the basis for this “CRISPR tolerance.” We observe that
E. faecalis
can maintain self-targeting constructs that direct Cas9 to cleave the chromosome, but at a fitness cost. Interestingly, DNA repair genes were not upregulated during self-targeting, but integrated prophages were strongly induced. We determined that low
cas9
expression contributes to this transient nonlethality and used this knowledge to develop a robust CRISPR-assisted genome-editing scheme. Our results suggest that
E. faecalis
has maximized the potential for DNA acquisition by attenuating its CRISPR machinery, thereby facilitating the acquisition of potentially beneficial MGEs that may otherwise be restricted by genome defense.

IMPORTANCE
CRISPR-Cas has provided a powerful toolkit to manipulate bacteria, resulting in improved genetic manipulations and novel antimicrobials. These powerful applications rely on the premise that CRISPR-Cas chromosome targeting, which leads to double-stranded DNA breaks, is lethal. In this study, we show that chromosomal CRISPR targeting in
Enterococcus faecalis
is transiently nonlethal. We uncover novel phenotypes associated with this “CRISPR tolerance” and, after determining its genetic basis, develop a genome-editing platform in
E. faecalis
with negligible off-target effects. Our findings reveal a novel strategy exploited by a bacterial pathogen to cope with CRISPR-induced conflicts to more readily accept DNA, and our robust CRISPR editing platform will help simplify genetic modifications in this organism.
Novel Xanthomonas campestris Long-Chain-Specific 3-Oxoacyl-Acyl Carrier Protein Reductase Involved in Diffusible Signal Factor Synthesis
Authors: Hu Zhe , Dong Huijuan , Ma Jin-Cheng , Yu Yonghong , Li Kai-Hui , Guo Qiao-Qiao , Zhang Chao , Zhang Wen-Bin , Cao Xinyun , Cronan John E. , Wang Haihong
Published: May 2018

The precursors of the diffusible signal factor (DSF) family signals of
Xanthomonas campestris
pv.
campestris
are 3-hydroxyacyl-acyl carrier protein (3-hydroxyacyl-ACP) thioesters having acyl chains of 12 to 13 carbon atoms produced by the fatty acid biosynthetic pathway. We report a novel 3-oxoacyl-ACP reductase encoded by the
X. campestris
pv.
campestris
XCC0416 gene (
fabG2
), which is unable to participate in the initial steps of fatty acyl synthesis. This was shown by the failure of FabG2 expression to allow growth at the nonpermissive temperature of an
Escherichia coli
fabG
temperature-sensitive strain. However, when transformed into the
E. coli
strain together with a plasmid bearing the
Vibrio harveyi
acyl-ACP synthetase gene (
aasS
), growth proceeded, but only when the medium contained octanoic acid.
In vitro
assays showed that FabG2 catalyzes the reduction of long-chain (≥C
8
) 3-oxoacyl-ACPs to 3-hydroxyacyl-ACPs but is only weakly active with shorter-chain (C
4
, C
6
) substrates. FabG1, the housekeeping 3-oxoacyl-ACP reductase encoded within the fatty acid synthesis gene cluster, could be deleted in a strain that overexpressed
fabG2
but only in octanoic acid-supplemented media. Growth of the
X. campestris
pv.
campestris
Δ
fabG1
strain overexpressing
fabG2
required
fabH
for growth with octanoic acid, indicating that octanoyl coenzyme A is elongated by
X. campestris
pv.
campestris
fabH
. Deletion of
fabG2
reduced DSF family signal production, whereas overproduction of either FabG1 or FabG2 in the Δ
fabG2
strain restored DSF family signal levels.

IMPORTANCE
Quorum sensing mediated by DSF signaling molecules regulates pathogenesis in several different phytopathogenic bacteria, including
Xanthomonas campestris
pv.
campestris
. DSF signaling also plays a key role in infection by the human pathogen
Burkholderia cepacia
. The acyl chains of the DSF molecules are diverted and remodeled from a key intermediate of the fatty acid synthesis pathway. We report a
Xanthomonas campestris
pv.
campestris
fatty acid synthesis enzyme, FabG2, of novel specificity that seems tailored to provide DSF signaling molecule precursors.