bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inactivation of the Major Hemolysin Gene Influences Expression of the Nonribosomal Peptide Synthetase Gene
swrA
in the Insect Pathogen Serratia sp. Strain SCBI
Authors: Petersen Lauren M. , LaCourse Kaitlyn , Schöner Tim A. , Bode Helge , Tisa Louis S. 
Published: August 2017

ABSTRACT

Hemolysins are important virulence factors for many bacterial pathogens, including
Serratia marcescens
. The role of the major hemolysin gene in the insect pathogen
Serratia
sp. strain SCBI was investigated using both forward and reverse-genetics approaches. Introduction of the major hemolysin gene into
Escherichia coli
resulted in a gain of both virulence and hemolytic activity. Inactivation of this hemolysin in
Serratia
sp. SCBI resulted in a loss of hemolysis but did not attenuate insecticidal activity. Unexpectedly, inactivation of the hemolysin gene in
Serratia
sp. SCBI resulted in significantly increased motility and increased antimicrobial activity. Reverse transcription-quantitative PCR (qRT-PCR) analysis of mutants with a disrupted hemolysin gene showed a dramatic increase in mRNA levels of a nonribosomal peptide synthetase gene,
swrA
, which produces the surfactant serrawettin W2. Mutation of the
swrA
gene in
Serratia
sp. SCBI resulted in highly varied antibiotic activity, motility, virulence, and hemolysis phenotypes that were dependent on the site of disruption within this 17.75-kb gene. When introduced into
E. coli
,
swrA
increases rates of motility and confers antimicrobial activity. While it is unclear how inactivation of the major hemolysin gene influences the expression of
swrA
, these results suggest that
swrA
plays an important role in motility and antimicrobial activity in
Serratia
sp. SCBI.

IMPORTANCE
The opportunistic Gram-negative bacteria of the genus
Serratia
are widespread in the environment and can cause human illness. A comparative genomics analysis between
Serratia marcescens
and a new
Serratia
species from South Africa, termed
Serratia
sp. strain SCBI, shows that these two organisms are closely related but differ in pathogenesis.
S. marcescens
kills
Caenorhabditis
nematodes, while
Serratia
sp. SCBI is not harmful and forms a beneficial association with them. This distinction presented the opportunity to investigate potential differences in regulation of common virulence mechanisms between these two species. With the emergence of antibiotic-resistant microorganisms, there is a widespread need to understand the regulation of pathogenesis. The significance of this study is the presentation of evidence for cross-pathway regulation of virulence factors and how the elimination of one mechanism may be compensated for by the upregulation of others.
Characterization of a Minimal Type of Promoter Containing the −10 Element and a Guanine at the −14 or −13 Position in Mycobacteria
Authors: Zhu Yan , Mao Chunyou , Ge Xingyi , Wang Zhongwei , Lu Pei , Zhang Yong , Chen Shiyun , Hu Yangbo 
Published: August 2017

ABSTRACT

Three key promoter elements, i.e., −10, −35, and T
−15
G
−14
N, are recognized by the σ subunit of RNA polymerase. Among them, promoters with the −10 element and either −35 or T
−15
G
−14
N are known to initiate transcription efficiently, but recent systematic analyses have identified a large group of promoters in
Mycobacterium tuberculosis
that contain only a −10 consensus. How these promoters initiate transcription remains poorly understood. Here, we show that promoters containing the −10 element and an upstream G located at the −14 or −13 position can successfully initiate transcription in mycobacteria. Importantly, this new type of promoter is active in the absence of other promoter consensuses, suggesting that it is a minimal promoter type. Mutation of the upstream G in promoters decreased the efficiencies of their binding with RNA polymerase and their abilities to initiate transcription in both
in vitro
and
in vivo
analyses. A glutamic acid in σ region 3.0 is essential for recognizing G
−14
and G
−13
and is conserved in both principal and principal-like σ factors in mycobacteria, indicating that recognition of this minimal type of promoter might be a common mechanism for transcription initiation. Consistently, more than 70% of the identified promoters in
M. tuberculosis
contained G
−14
or G
−13
upstream of the conserved −10 element, and thousands of promoters in representative mycobacterial species have been predicted using the −10 consensus and G
−14
or G
−13
. Altogether, our study presents a universal mechanism for transcription initiation from a minimal promoter in mycobacteria, which might also be applicable to other bacteria.

IMPORTANCE
In contrast to the detailed information for recognizing classic promoters in the model organism
Escherichia coli
, very little is known about how transcription is initiated in the human pathogen
Mycobacterium tuberculosis
. In this study, we characterized a new type of promoter in mycobacteria that requires only a −10 consensus and an upstream G
−14
or G
−13
. Residues important for recognizing the −10 element and the upstream G are conserved in σ
A
and σ
B
from mycobacterial species. According to such features, thousands of promoters in mycobacteria can be predicted using the −10 consensus and G
−14
or G
−13
, which suggests that transcription from this new type of promoter might be widespread. Our findings provide insightful information for characterizing promoters in mycobacteria.
Distinctive Roles for Periplasmic Proteases in the Maintenance of Essential Outer Membrane Protein Assembly
Authors: Soltes Garner R. , Martin Nicholas R. , Park Eunhae , Sutterlin Holly A. , Silhavy Thomas J. 
Published: August 2017

ABSTRACT

Outer membrane protein (OMP) biogenesis in
Escherichia coli
is a robust process essential to the life of the organism. It is catalyzed by the β-barrel assembly machine (Bam) complex, and a number of quality control factors, including periplasmic chaperones and proteases, maintain the integrity of this trafficking pathway. Little is known, however, about how periplasmic proteases recognize and degrade OMP substrates when assembly is compromised or whether different proteases recognize the same substrate at distinct points in the assembly pathway. In this work, we use well-defined assembly-defective mutants of LptD, the essential lipopolysaccharide assembly translocon, to show that the periplasmic protease DegP degrades substrates with assembly defects that prevent or impair initial contact with Bam, causing the mutant protein to accumulate in the periplasm. In contrast, another periplasmic protease, BepA, degrades a LptD mutant substrate that has engaged the Bam complex and formed a nearly complete barrel. Furthermore, we describe the role of the outer membrane lipoprotein YcaL, a protease of heretofore unknown function, in the degradation of a LptD substrate that has engaged the Bam complex but is stalled at an earlier step in the assembly process that is not accessible to BepA. Our results demonstrate that multiple periplasmic proteases monitor OMPs at distinct points in the assembly process.

IMPORTANCE
OMP assembly is catalyzed by the essential Bam complex and occurs in a cellular environment devoid of energy sources. Assembly intermediates that misfold can compromise this essential molecular machine. Here we demonstrate distinctive roles for three different periplasmic proteases that can clear OMP substrates with folding defects that compromise assembly at three different stages. These quality control factors help ensure the integrity of the permeability barrier that contributes to the intrinsic resistance of Gram-negative organisms to many antibiotics.
Preclinical development of MGO Manuka Honey microemulsion for blepharitis management
Authors: Craig Jennifer P , Rupenthal Ilva D , Seyfoddin Ali , Cheung Isabella M Y , Uy Benedict , Wang Michael T M , Watters Grant A , Swift Simon 
Published: August 2017

ObjectiveTo evaluate thein vitroantimicrobial effects of cyclodextrin-complexed and uncomplexed Manuka honey on bacteria commonly associated with blepharitis, andin vivorabbit eye tolerability of a cyclodextrin-complexed methylglyoxal (MGO) Manuka Honey microemulsion (MHME).Methods and analysisIn vitrophase: Bacterial growth inhibition was assessed by area under the growth curve (AUC) forStaphylococcus aureus, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) forS. aureus, Staphylococcus epidermidisandPseudomonas aeruginosawith cyclodextrin-complexed and uncomplexed Manuka honey were determined.In vivophase: Six rabbits were administered 20 µL of MHME (at 1:10 dilution) to the right eye (treated) and 20 µL of saline to the left eye (control) daily, for 5 days. Tear evaporation, production, osmolarity, lipid layer, conjunctival hyperaemia and fluorescein staining were assessed daily, before and 15 min after instillation.ResultsIn vitrophase: The relative AUC for cyclodextrin-complexed Manuka honey was lower than that of uncomplexed honey at both 250 and 550 mg/kg of MGO (both p <0.05). Cyclodextrin-complexed honey had lower MIC and MBC than uncomplexed honey for bothS. aureusandS. epidermidis, but notP. aeruginosa.In vivophase: No significant changes were observed in the parameters assessed in either treated or control eyes (all p >0.05).ConclusionOverall, antimicrobial potency of cyclodextrin-complexed Manuka honey was greater than uncomplexed honey. No significant immediate or cumulative adverse effects were observed with MHME application on rabbit eyes, supporting future conduct of clinical safety and tolerability trials in human subjects.
Downregulation of interferon-γ-induced protein 10 in the tears of patients with Stevens-Johnson syndrome with severe ocular complications in the chronic stage
Authors: Ueta Mayumi , Nishigaki Hiromi , Sotozono Chie , Kinoshita Shigeru 
Published: August 2017

ObjectivesStevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are acute inflammatory vesiculobullous reactions of the skin and mucosa such as the ocular surface, oral cavity and genitals. Severe ocular complications (SOC) arise in some patients with SJS/TEN diagnosed by dermatologists. To investigate the pathophysiology of ocular surface inflammation in SJS/TEN with SOC in the chronic stage, we examined cytokines in the tears of patients with ocular surface diseases and healthy controls.ParticipantsSJS/TEN eyes in the chronic stage (n>30), healthy eyes (n>20, controls) and eyes (n>20) from patients with atopic keratoconjunctivitis representing different ocular surface inflammatory disorders.Primary outcome measuresTear samples were collected on Schirmer's measurement strips. To measure the level of various cytokines in the tears we used BD CBA Flex sets.Study designAn observational study (case–control study).ResultsWe recorded the level of interleukin (IL)-6, IL-8, eotaxin, macrophage inflammatory protein (MIP)-1β, RANTES (regulated on activation, normal T cell expressed and secreted), interferon gamma (IFN)-γ, monocyte chemoattractant protein-1, IFN-γ-induced protein 10 (IP-10) and total IgE. We found that compared with the controls, in SJS/TEN with SOC, IL-6, IL-8, eotaxin and MIP-1β were significantly upregulated while IP-10 was significantly downregulated. Compared with atopic keratoconjunctivitis, IP-10 was significantly downregulated in SJS/TEN with SOC; on the other hand, total IgE was significantly upregulated in atopic keratoconjunctivitis compared with SJS/TEN with SOC.ConclusionsIP-10 in tears may be a biomarker to distinguish between chronic SJS/TEN with SOC and other ocular inflammatory disorders such as atopic keratoconjunctivitis.
A pilot biomechanical assessment of curling deliveries: is toe sliding more likely to cause knee injury than flatfoot sliding?
Authors: Robertson Iona , Arnold Graham P , Wang Weijie , Drew Tim S , Nasir Sadiq , MacDonald Calum , Abboud Rami J 
Published: August 2017

BackgroundThe aim of this study was to determine whether toe sliding is more likely to cause knee injuries than flatfoot sliding in curling.MethodsTwelve curlers participated in the study, each delivering 12 stones. Six stones per volunteer were delivered using a flatfoot slide and six were delivered using a toe slide. The Pedar-X in-shoe pressure system recorded the plantar pressure during each of the slides, while a sagittal plane digital video recorded the body position of the curler. Measurements were taken from the video recordings using a software overlay program (MB Ruler), and this, combined with the Pedar-X data, gave the overall joint force in the tuck knee.ResultsThe knee joint force for toe sliding was more than double that of flatfoot sliding (p<0.05). There was a strong correlation between the increase in knee joint force and the increase in the moment arm of the ground reaction force. Images produced using the three-dimensional Vicon system confirm that toe sliding produces a larger moment arm than flatfoot sliding.ConclusionInjuries are more likely to occur in toe sliding, compared with flatfoot sliding, due to the increase in force and moment, pushing the weight of the curler forward over the knee, which could make the adopted position less stable. Curlers might consider avoiding toe sliding to reduce the risk of knee injuries if the two types of delivery could be performed equally well.
Interval exercise increases angiogenic cell function in postmenopausal women
Authors: Harris Emma , Rakobowchuk Mark , Birch Karen M 
Published: August 2017

IntroductionExercise can help to negate the increased cardiovascular disease risk observed in women after the menopausal transition. This study sought to determine whether interval or continuous exercise has differential effects on endothelial function and circulating angiogenic cell (CAC) number and function in postmenopausal women.MethodsFifteen healthy postmenopausal women completed a 30 min acute moderate-intensity continuous (CON) and interval exercise (MOD-INT) session on a cycle ergometer on separate days. Nine participants completed a further single 30 min acute heavy-intensity interval (HEAVY-INT) exercise session. Brachial artery flow-mediated dilation (FMD) was assessed pre-exercise and 15 min post-exercise session. CAC number and colony-forming capacity in vitro were assessed post exercise and compared with resting levels.ResultsFMD and CAC number did not change post exercise regardless of exercise type (p>0.05). However, the number (mean±SD) of colony-forming units (CFUs) increased from visit 1 (12±10 CFUs/well) to post MOD-INT (32±30 CFUs/well) and post HEAVY-INT (38±23 CFUs/well) but not post CON (13±14 CFUs/well).ConclusionA single session of interval exercise is more effective than a continuous exercise session for increasing the intercellular communication of CACs, regardless of exercise intensity. The enhanced ability of CACs to form colonies may reflect an increased number and/or function of angiogenic T-cells. The repeated exertions to higher work rates during interval exercise may explain this response. Repeated exercise sessions might be required to improve FMD in postmenopausal women.
Characteristics and occurrence of type 2 myocardial infarction in emergency department patients: a prospective study
Authors: Greenslade Jaimi H , Adikari Thushani , Mueller Christian , Sandoval Yader , Nestelberger Thomas , Parsonage William , Hawkins Tracey , Cullen Louise 
Published: August 2017

ObjectiveTo identify differences in prevalence, demographics, clinical features and outcomes for type 1 myocardial infarction (T1MI) and type 2 myocardial infarction (T2MI) in a cohort of patients presenting to the Emergency Department (ED) with chest pain.MethodsThis was a post hoc analysis of data collected from two prospective studies. Data were collected between November 2008 and February 2011 for the first study, and between February 2011 and March 2014 for the second. Participants were patients presenting to the ED with symptoms suggestive of acute coronary syndrome (ACS). The outcome was 30-day diagnosis; classified into T1MI, T2MI or non-MI. Descriptive statistics were used to compare the demographics, clinical history and presenting symptoms across diagnoses (T1MI, T2MI and non-MI). Cumulative mortality over 1 year was compared for T1MI and T2MI.Results147 patients (6.3%; 95% CI 5.3% to 7.3%) were classified as T1MI and 52 (2.2%; 95% CI 1.7% to 2.9%) were classified as T2MI. T2MIs were more likely to be female (OR 4.71, 95% CI 2.28 to 9.76), have an abnormal but non-ischaemic ECG (OR 2.95, 95% CI 1.45 to 6.00), report prior hypertension (OR 2.83, 95% CI 1.35 to 6.12), have tachycardia (OR 9.26, 95% CI 3.08 to 30.77) and pain at rest (OR 3.04, 95% CI 1.28 to 8.02) compared with T1MI. One-year mortality was similar between T1MI and T2MI (9% and 14.6%, respectively, p=0.37).ConclusionsT2MIs comprised one quarter of all MIs diagnosed in the ED. Among patients presenting to the ED with symptoms of ACS, symptoms do not allow clinicians to reliably differentiate patients with T1MI and T2MI. Prior hypertension, tachycardia and abnormal non-ischaemic ECGs are seen more often in T2MI compared with T1MI. One-year mortality was substantial in patients with T1MI and T2MI, but low power precludes conclusions about mortality differences between groups.
Shifting disease burden in low and middle-income countries: a 14-year survival analysis of childhood mortality in Bangladesh
Authors: Alonge Olakunle , He Siran , Hoque Dewan Emdadul , Salam Shumona Sharmin , Islam Irteja , El-Arifeen Shams , Hyder Adnan A 
Published: August 2017

BackgroundThe objective of this study is to compare all-cause mortality and drowning-specific mortality rates and survival times among birth cohorts of children from rural Bangladesh over a 14-year period.MethodSeven birth cohorts of children aged 12–59 months were created using data from the Matlab Health and Demographic Surveillance System in Bangladesh. Each cohort represents children born within a 2-year interval between 1 July 1995 and 30 June 2009, who were then evaluated over a 2-year snapshot. All-cause and drowning-specific mortality rates were compared for each cohort using the oldest cohort (cohort 1) as reference. A Cox proportional model was used to estimate hazard rate ratios (HRR) comparing the cohorts, and adjusted for key independent variables. Kaplan-Meier survivor function was estimated for each birth cohort and compared with cohort 1 using log-rank test.ResultsThe adjusted HRR for all-cause mortality showed that children in cohorts 4, 5, 6 and 7 had significantly lower hazard rate compared with cohort 1 with a dose–response relationship, the adjusted HRRs were 0.51 (95% CI 0.31, 0.84), 0.53 (95% CI 0.32, 0.87), 0.44 (95% CI 0.26, 0.76) and 0.42 (95% CI 0.24, 0.74), respectively. For drowning, none of the adjusted HRR was statistically significant. Mother's primary education and being married were protective of risk of death from all causes.ConclusionWhereas child mortality rates from all causes declined remarkably between 1998 and 2012 in rural Bangladesh, drowning-specific mortality rates remained unchanged. This shifting burden of disease underscores the epidemiological transition in the childhood causes of death in Bangladesh and the need for urgent action to review child health interventions.
The new features of Fortran 2015
Authors: Reid John 
Published: August 2017

aim of this paper is to summarize the new features of the Fortran standard that is expected to be published in 2018. It is known informally as Fortran 2015 because the choice of features to include was chosen in 2015. We take as our starting point Fortran 2008 (ISO/IEC 2010).
Two official extensions have been published as Technical Specifications. ISO/IEC (2012) specifies further features for interoperability of Fortran with C and ISO/IEC (2015) specifies additional parallel features. WG5 committed itself to include both of these in Fortran 2015. The introduction of a new IEEE standard for floating-point arithmetic (ISO/IEC/IEEE 2011) necessitated changes to the IEEE modules. Beyond these features, WG5 decided to limit changes to the removal of deficiencies and discrepancies, which by definition are all small.
For an informal description of Fortran 2008, see Metcalf, Reid and Cohen (2011).
Model of Murine Ventricular Cardiac Tissue for In Vitro Kinematic-Dynamic Studies of Electromagnetic and β-Adrenergic Stimulation
Authors: Fassina Lorenzo , Cornacchione Marisa , Pellegrini Manuela , Mognaschi Maria Evelina , Gimmelli Roberto , Isidori Andrea Maria , Lenzi Andrea , Magenes Giovanni , Naro Fabio 
Published: August 2017

In a model of murine ventricular cardiac tissue in vitro, we have studied the inotropic effects of electromagnetic stimulation (frequency, 75 Hz), isoproterenol administration (10 μM), and their combination. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of beating cardiac syncytia starting from the video registration of their contraction movement. We have found that the electromagnetic stimulation is able to counteract the β-adrenergic effect of isoproterenol and to elicit an antihypertrophic response.
Early-Stage Metastasis Requires Mdm2 and Not p53 Gain of Function
Authors: Hauck Paula M. , Wolf Eric R. , Olivos David J. , Batuello Christopher N. , McElyea Kyle C. , McAtarsney Ciarán P. , Cournoyer R. Michael , Sandusky George E. , Mayo Lindsey D. 
Published: August 2017

Abstract
Metastasis of cancer cells to distant organ systems is a complex process that is initiated with the programming of cells in the primary tumor. The formation of distant metastatic foci is correlated with poor prognosis and limited effective treatment options. We and others have correlated Mouse double minute 2 (Mdm2) with metastasis; however, the mechanisms involved have not been elucidated. Here, it is reported that shRNA-mediated silencing of Mdm2 inhibits epithelial–mesenchymal transition (EMT) and cell migration. In vivo analysis demonstrates that silencing Mdm2 in both post-EMT and basal/triple-negative breast cancers resulted in decreased primary tumor vasculature, circulating tumor cells, and metastatic lung foci. Combined, these results demonstrate the importance of Mdm2 in orchestrating the initial stages of migration and metastasis.
Implication: Mdm2 is the major factor in the initiation of metastasis. Mol Cancer Res; 15(11); 1598–607. ©2017 AACR.