bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lantibiotic Reductase LtnJ Substrate Selectivity Assessed with a Collection of Nisin Derivatives as Substrates
Authors: Mu Dongdong , Montalbán-López Manuel , Deng Jingjing , Kuipers Oscar P. 
Published: March 2015

ABSTRACT

Lantibiotics are potent antimicrobial peptides characterized by the presence of dehydrated amino acids, dehydroalanine and dehydrobutyrine, and (methyl)lanthionine rings. In addition to these posttranslational modifications, some lantibiotics exhibit additional modifications that usually confer increased biological activity or stability on the peptide. LtnJ is a reductase responsible for the introduction of
d
-alanine in the lantibiotic lacticin 3147. The conversion of
l
-serine into
d
-alanine requires dehydroalanine as the substrate, which is produced
in vivo
by the dehydration of serine by a lantibiotic dehydratase, i.e., LanB or LanM. In this work, we probe the substrate specificity of LtnJ using a system that combines the nisin modification machinery (dehydratase, cyclase, and transporter) and the stereospecific reductase LtnJ in
Lactococcus lactis
. We also describe an improvement in the production yield of this system by inserting a putative attenuator from the nisin biosynthesis gene cluster in front of the
ltnJ
gene. In order to clarify the sequence selectivity of LtnJ, peptides composed of truncated nisin and different mutated C-terminal tails were designed and coexpressed with LtnJ and the nisin biosynthetic machinery. In these tails, serine was flanked by diverse amino acids to determine the influence of the surrounding residues in the reaction. LtnJ successfully hydrogenated peptides when hydrophobic residues (Leu, Ile, Phe, and Ala) were flanking the intermediate dehydroalanine, while those in which dehydroalanine was flanked by one or two polar residues (Ser, Thr, Glu, Lys, and Asn) or Gly were either less prone to be modified by LtnJ or not modified at all. Moreover, our results showed that dehydrobutyrine cannot serve as a substrate for LtnJ.
Gene Loss and Lineage-Specific Restriction-Modification Systems Associated with Niche Differentiation in the Campylobacter jejuni Sequence Type 403 Clonal Complex
Authors: Morley Laura , McNally Alan , Paszkiewicz Konrad , Corander Jukka , Méric Guillaume , Sheppard Samuel K. , Blom Jochen , Manning Georgina 
Published: March 2015

ABSTRACT

Campylobacter jejuni
is a highly diverse species of bacteria commonly associated with infectious intestinal disease of humans and zoonotic carriage in poultry, cattle, pigs, and other animals. The species contains a large number of distinct clonal complexes that vary from host generalist lineages commonly found in poultry, livestock, and human disease cases to host-adapted specialized lineages primarily associated with livestock or poultry. Here, we present novel data on the ST403 clonal complex of
C. jejuni
, a lineage that has not been reported in avian hosts. Our data show that the lineage exhibits a distinctive pattern of intralineage recombination that is accompanied by the presence of lineage-specific restriction-modification systems. Furthermore, we show that the ST403 complex has undergone gene decay at a number of loci. Our data provide a putative link between the lack of association with avian hosts of
C. jejuni
ST403 and both gene gain and gene loss through nonsense mutations in coding sequences of genes, resulting in pseudogene formation.
In-Frame and Unmarked Gene Deletions in Burkholderia cenocepacia via an Allelic Exchange System Compatible with Gateway Technology
Authors: Fazli Mustafa , Harrison Joe J. , Gambino Michela , Givskov Michael , Tolker-Nielsen Tim 
Published: March 2015

ABSTRACT

Burkholderia cenocepacia
is an emerging opportunistic pathogen causing life-threatening infections in immunocompromised individuals and in patients with cystic fibrosis, which are often difficult, if not impossible, to treat. Understanding the genetic basis of virulence in this emerging pathogen is important for the development of novel treatment regimes. Generation of deletion mutations in genes predicted to encode virulence determinants is fundamental to investigating the mechanisms of pathogenesis. However, there is a lack of appropriate selectable and counterselectable markers for use in
B. cenocepacia
, making its genetic manipulation problematic. Here we describe a Gateway-compatible allelic exchange system based on the counterselectable
pheS
gene and the I-SceI homing endonuclease. This system provides efficiency in cloning homology regions of target genes and allows the generation of precise and unmarked gene deletions in
B. cenocepacia
. As a proof of concept, we demonstrate its utility by deleting the
Bcam1349
gene, encoding a cyclic di-GMP (c-di-GMP)-responsive regulator protein important for biofilm formation.
One-Pot Production of
l
-
threo
-3-Hydroxyaspartic Acid Using Asparaginase-Deficient Escherichia coli Expressing Asparagine Hydroxylase of Streptomyces coelicolor A3(2)
Authors: Hara Ryotaro , Nakano Masashi , Kino Kuniki 
Published: March 2015

ABSTRACT

We developed a novel process for efficient synthesis of
l
-
threo
-3-hydroxyaspartic acid (
l
-THA) using microbial hydroxylase and hydrolase. A well-characterized mutant of asparagine hydroxylase (AsnO-D241N) and its homologous enzyme (SCO2693-D246N) were adaptable to the direct hydroxylation of
l
-aspartic acid; however, the yields were strictly low. Therefore, the highly stable and efficient wild-type asparagine hydroxylases AsnO and SCO2693 were employed to synthesize
l
-THA. By using these recombinant enzymes,
l
-THA was obtained by
l
-asparagine hydroxylation by AsnO followed by amide hydrolysis by asparaginase via 3-hydroxyasparagine. Subsequently, the two-step reaction was adapted to one-pot bioconversion in a test tube.
l
-THA was obtained in a small amount with a molar yield of 0.076% by using intact
Escherichia coli
expressing the
asnO
gene, and thus, two asparaginase-deficient mutants of
E. coli
were investigated. A remarkably increased
l
-THA yield of 8.2% was obtained with the asparaginase I-deficient mutant. When the expression level of the
asnO
gene was enhanced by using the T7 promoter in
E. coli
instead of the
lac
promoter, the
l
-THA yield was significantly increased to 92%. By using a combination of the
E. coli
asparaginase I-deficient mutant and the T7 expression system, a whole-cell reaction in a jar fermentor was conducted, and consequently,
l
-THA was successfully obtained from
l
-asparagine with a maximum yield of 96% in less time than with test tube-scale production. These results indicate that asparagine hydroxylation followed by hydrolysis would be applicable to the efficient production of
l
-THA.
Hierarchy of Carbon Source Utilization in Soil Bacteria: Hegemonic Preference for Benzoate in Complex Aromatic Compound Mixtures Degraded by Cupriavidus pinatubonensis Strain JMP134
Authors: Pérez-Pantoja Danilo , Leiva-Novoa Pablo , Donoso Raúl A. , Little Cedric , Godoy Margarita , Pieper Dietmar H. , González Bernardo 
Published: March 2015

ABSTRACT

Cupriavidus pinatubonensis
JMP134, like many other environmental bacteria, uses a range of aromatic compounds as carbon sources. Previous reports have shown a preference for benzoate when this bacterium grows on binary mixtures composed of this aromatic compound and 4-hydroxybenzoate or phenol. However, this observation has not been extended to other aromatic mixtures resembling a more archetypal context. We carried out a systematic study on the substrate preference of
C. pinatubonensis
JMP134 growing on representative aromatic compounds channeled through different catabolic pathways described in aerobic bacteria. Growth tests of nearly the entire set of binary combinations and in mixtures composed of 5 or 6 aromatic components showed that benzoate and phenol were always the preferred and deferred growth substrates, respectively. This pattern was supported by kinetic analyses that showed shorter times to initiate consumption of benzoate in aromatic compound mixtures. Gene expression analysis by real-time reverse transcription-PCR (RT-PCR) showed that, in all mixtures, the repression by benzoate over other catabolic pathways was exerted mainly at the transcriptional level. Additionally, inhibition of benzoate catabolism suggests that its multiple repressive actions are not mediated by a sole mechanism, as suggested by dissimilar requirements of benzoate degradation for effective repression in different aromatic compound mixtures. The hegemonic preference for benzoate over multiple aromatic carbon sources is not explained on the basis of growth rate and/or biomass yield on each single substrate or by obvious chemical or metabolic properties of these aromatic compounds.
Houseflies (Musca domestica) as Vectors for Extended-Spectrum β-Lactamase-Producing Escherichia coli on Spanish Broiler Farms
Authors: Solà-Ginés Marc , González-López Juan José , Cameron-Veas Karla , Piedra-Carrasco Nuria , Cerdà-Cuéllar Marta , Migura-Garcia Lourdes 
Published: March 2015

ABSTRACT

Flies may act as potential vectors for the spread of resistant bacteria to different environments. This study was intended to evaluate the presence of
Escherichia coli
strains resistant to cephalosporins in flies captured in the areas surrounding five broiler farms. Phenotypic and molecular characterization of the resistant population was performed by different methods: MIC determination, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and phylotyping. The presence of extended-spectrum beta-lactamase (ESBL) genes, their plasmid location, and the mobile genetic elements involved in their mobilization were studied. Additionally, the presence of 35 genes associated with virulence was evaluated. Out of 682 flies captured, 42 yielded ESBL-producing
E. coli
. Of these isolates, 23 contained
bla
CTX-M-1
, 18 contained
bla
CTX-M-14
, and 1 contained
bla
CTX-M-9
. ESBL genes were associated mainly with the presence of the IncI1 and IncFIB replicons. Additionally, all the strains were multiresistant, and five of them also harbored
qnrS
. Identical PFGE profiles were found for
E. coli
isolates obtained from flies at different sampling times, indicating a persistence of the same clones in the farm environment over months. According to their virulence genes, 81% of the isolates were considered avian-pathogenic
E. coli
(APEC) and 29% were considered extraintestinal pathogenic
E. coli
(ExPEC). The entrance of flies into broiler houses constitutes a considerable risk for colonization of broilers with multidrug-resistant
E. coli
. ESBLs in flies reflect the contamination status of the farm environment. Additionally, this study demonstrates the potential contribution of flies to the dissemination of virulence and resistance genes into different ecological niches.
Unusual Case of Pyogenic Spondylodiscitis, Vertebral Osteomyelitis and Bilateral Psoas Abscesses after Acupuncture: Diagnosis and Treatment with Interventional Management
Authors: He Chengjian , Wang Tao , Gu Yifeng , Tian Qinghua , Zhou Bi , Wu Chungen 
Published: March 2015

Background We report, for the first time, a case of pyogenic spondylodiscitis combined with vertebral osteomyelitis and bilateral psoas abscesses after acupuncture. Case History A 60-year-old man was diagnosed with rectal cancer, and radical rectectomy and permanent colostomy were carried out. However, 3 years after the surgery the patient complained of pain in the lower back, and the symptoms worsened after seven sessions of acupuncture. Technetium 99m-labelled methylene diphosphonate (99mTc-MDP) bone scintigraphy (BS) revealed abnormal uptake of 99mTc-MDP in the L4 and L5 vertebrae. He was admitted to our hospital because of suspected bone metastases from rectal cancer. He was diagnosed with infection based on a history of acupuncture and the findings of enhanced MRI and CT. Percutaneous lumbar discectomy (PLD), external drainage and irrigation using antibiotics were carried out to treat the L4−5 disc. Pathological analyses and bacterial culture of the resected disc confirmed infection with group C streptococcus. Postoperative antibiotic treatment resulted in significant pain relief on the third day and gradual complete relief. Considerable improvement was seen on CT and MRI at follow-up. Conclusions We consider it highly likely that this patient's infection was caused by acupuncture. In patients with malignancy, abnormal uptake of 99mTc-MDP in BS may signify bone metastasis but can also be observed in bone infections. PLD can be used to resect diseased discs to relieve pain quickly and to prevent herniation of lumbar discs. After PLD, external drainage can be employed for abscess drainage, decompression and perfusion of antibiotics. PLD may serve as an alternative to open surgery for pyogenic spondylodiscitis.
Healthcare resource implications of hypoglycemia-related hospital admissions and inpatient hypoglycemia: retrospective record-linked cohort studies in England
Authors: McEwan Philip , Larsen Thorsted Brian , Wolden Michael , Jacobsen Judith , Evans Marc 
Published: March 2015

ObjectiveUsing a retrospective cohort study, the mean length of hospital stay (LoS) and total per-patient expenditure for hypoglycemia requiring admission to hospital were estimated. In a separate matched retrospective cohort study, the effect of inpatient hypoglycemia on LoS, expenditure, and risk of all-cause mortality while admitted was investigated.MethodsThe cohorts consisted of patients aged ≥18 years with a diagnosis of type 1 or 2 diabetes between January 1, 2002 and October 30, 2012 in the Clinical Practice Research Datalink database, who had initiated insulin treatment and had a recording of hypoglycemia in the same period. In the matched retrospective cohort study, exposed patients (who experienced hypoglycemia in hospital) were case-matched with patients who did not experience hypoglycemia during admission (unexposed). Generalized linear regression was used to estimate LoS. Risk of all-cause mortality was evaluated via logistic regression.ResultsIn the retrospective cohort study (1131 patients), mean LoS was 5.46 (95% CI 4.62 to 6.45) days for type 1 diabetes, and 5.04 (95% CI 4.46 to 5.71) days for type 2 diabetes. Mean cost per admission was £1034 (95% CI £855 to £1253). In the matched retrospective cohort study (1079 pairs of patients), exposed patients had a mean LoS of 11.91 days (95% CI 10.96 to 12.94 days) versus 4.80 (95% CI 4.41 to 5.23) for unexposed patients, p<0.0001. Exposed patients had a higher mortality risk compared with unexposed patients (OR 1.439 (95% CI 1.060to 1.952), p=0.0195). Total average per-patient cost for exposed patients was GBP (£)2235, 40% (p<0.0001) higher than total average admission cost in unexposed patients.ConclusionsHypoglycemia has a significant negative impact on patient outcomes, healthcare resource use, and expenditure.
Effectiveness of general preconception care accompanied by a recruitment approach: protocol of a community-based cohort study (the Healthy Pregnancy 4 All study)
Authors: van Voorst Sabine F , Vos Amber A , de Jong-Potjer Lieke C , Waelput Adja J M , Steegers Eric A P , Denktas¸ Semiha 
Published: March 2015

IntroductionPromotion of healthy pregnancies has gained high priority in the Netherlands because of the relative unfavourable perinatal outcomes. In response, a nationwide study Healthy Pregnancy 4 All (HP4ALL) has been initiated. One of the substudies within HP4ALL focuses on preconception care (PCC). PCC is an opportunity to detect and eliminate risk factors before conception to optimise health before organogenesis and placentation. The main objectives of the PCC substudy are (1) to assess the effectiveness of a recruitment strategy for the PCC health services and (2) to assess the effectiveness of individual PCC consultations.Methods/analysisProspective cohort study in neighbourhoods of 14 municipalities with perinatal mortality and morbidity rates exceeding the nation's average. The theoretical framework of the PCC substudy is based on Andersen's model of healthcare utilisation (a model that evaluates the utilisation of healthcare services from a sociological perspective). Women aged 18 up to and including 41 years are targeted for utilisation of the PCC health service by a four armed recruitment strategy. The PCC health service consists of an individual PCC consultation consisting of (1) initial risk assessment and risk management and (2) a follow-up consultation to assess adherence to the management plan. The primary outcomes regarding the effectiveness of consultations is behavioural change regarding folic acid supplementation, smoking cessation, cessation of alcohol consumption and illicit substance use. The primary outcome regarding the effectiveness of the recruitment strategy is the number of women successfully recruited and the outreach in terms of which population is reached in comparison to the approached population. Data collection consists of registration in the database of women that enrol for a visit to the individual PCC consultations (women successfully recruited), and preconsultation and postconsultation measurements among the included study population (by questionnaires, anthropometric measurements and biomarkers). Sample size calculation resulted in a sample size of n=839 women.Ethics and disseminationApproval for this study has been obtained from the Medical Ethical Committee of the Erasmus Medical Center of Rotterdam (MEC 2012-425). Results will be published and presented at international conferences.
Determination of risk factors for drug-related problems: a multidisciplinary triangulation process
Authors: Kaufmann Carole P , Stämpfli Dominik , Hersberger Kurt E , Lampert Markus L 
Published: March 2015

Introduction and objectivesDrug-related problems (DRPs) constitute a frequent safety issue among hospitalised patients leading to patient harm and increased healthcare costs. Because many DRPs are preventable, the specific risk factors that facilitate their occurrence are of considerable interest. The objective of our study was to assess risk factors for the occurrence of DRPs with the intention to identify patients at risk for DRPs to guide and target preventive measures where they are needed most in patients.DesignTriangulation process using a mixed methods approach.MethodsWe conducted an expert panel, using the nominal group technique (NGT) and a qualitative analysis, to gather risk factors for DRPs. The expert panel consisted of two consultant hospital physicians (internal medicine and geriatrics), one emergency physician, one independent general practitioner, one clinical pharmacologist, one clinical pharmacist, one registered nurse, one home care nurse and two independent community pharmacists. The literature was searched for additional risk factors. Gathered factors from the literature search and the NGT were assembled and validated in a two-round Delphi questionnaire.ResultsThe NGT resulted in the identification of 33 items with 13 additional risk factors from the qualitative analysis of the discussion. The literature search delivered another 39 risk factors. The 85 risk factors were refined to produce 42 statements for the Delphi online questionnaire. Of these, 27 risk factors were judged to be ‘important’ or ‘rather important’.ConclusionsThe gathered risk factors may help to characterise and identify patients at risk for DRPs and may enable clinical pharmacists to guide and target preventive measures in order to limit the occurrence of DRPs. As a further step, these risk factors will serve as the basis for a screening tool to identify patients at risk for DRPs.
Remote supervision of medical training via videoconference in northern Australia: a qualitative study of the perspectives of supervisors and trainees
Authors: Cameron Miriam , Ray Robin , Sabesan Sabe 
Published: March 2015

ObjectivesTelemedicine has revolutionised the ability to provide care to patients, relieve professional isolation and provide guidance and supervision to junior medical officers in rural areas. This study evaluated the Townsville teleoncology supervision model for the training of junior medical officers in rural areas of North Queensland, Australia. Specifically, the perspectives of junior and senior medical officers were explored to identify recommendations for future implementation.DesignA qualitative approach incorporating observation and semistructured interviews was used to collect data. Interviews were uploaded into NVivo 10 data management software. Template analysis enabled themes to be tested and developed through consensus between researchers.SettingOne tertiary level and four secondary level healthcare centres in rural and regional Queensland, Australia.Participants10 junior medical officers (Interns, Registrars) and 10 senior medical officers (Senior Medical Officers, Consultants) who participated in the Townsville teleoncology model of remote supervision via videoconference (TTMRS) were included in the study.Primary and Secondary outcome measuresPerspectives on the telemedicine experience, technology, engagement, professional support, satisfaction and limitations were examined. Perspectives on topics raised by participants were also examined as the interviews progressed.ResultsFour major themes with several subthemes emerged from the data: learning environment, beginning the learning relationship, stimulus for learning and practicalities of remote supervision via videoconference. While some themes were consistent with the current literature, new themes like increased professional edge, recognising non-verbal cues and physical examination challenges were identified.ConclusionsRemote supervision via videoconference provides readily available guidance to trainees supporting their delivery of appropriate care to patients. However, resources required for upskilling, training in the use of supervision via videoconference, administration issues and nursing support, as well as physical barriers to examinations, must be addressed to enable more efficient implementation.
The effectiveness of self-management support interventions for men with long-term conditions: a systematic review and meta-analysis
Authors: Galdas Paul , Fell Jennifer , Bower Peter , Kidd Lisa , Blickem Christian , McPherson Kerri , Hunt Kate , Gilbody Simon , Richardson Gerry 
Published: March 2015

ObjectivesTo assess the effectiveness of self-management support interventions in men with long-term conditions.MethodsA quantitative systematic review with meta-analysis.Data sourcesThe Cochrane Database of Systematic Reviews was searched to identify published reviews of self-management support interventions. Relevant reviews were screened to identify randomised controlled trials (RCTs) of self-management support interventions conducted in men alone, or which analysed the effects of interventions by sex.Review methodsData on relevant outcomes, patient populations, intervention type and study quality were extracted. Quality appraisal was conducted using the Cochrane Risk of Bias Tool. Meta-analysis was conducted to compare the effects of interventions in men, women, and mixed-sex sub-groups.Results40 RCTs of self-management support interventions in men, and 20 eligible RCTs where an analysis by sex was reported, were included in the review. Meta-analysis suggested that physical activity, education, and peer support-based interventions have a positive impact on quality of life in men. However, there is currently insufficient evidence to make strong statements about whether self-management support interventions show larger, similar or smaller effects in men compared with women and mixed-sex groups.ConclusionsClinicians may wish to consider whether certain types of self-management support (eg, physical activity, education, peer support) are particularly effective in men, although more research is needed to fully determine and explore this.