Description: The R263K substitution in integrase has been selected in tissue culture with dolutegravir (DTG) and has been reported for several treatment-experienced individuals receiving DTG as part of salvage therapy. The R263K substitution seems to be incompatible with the presence of common resistance mutations associated with raltegravir (RAL), a different integrase strand transfer inhibitor (INSTI). T66I is a substitution that is common in individuals who have developed resistance against a different INSTI termed elvitegravir (EVG), but it is not known whether these two mutations might be compatible in the context of resistance against DTG or what impact the combination of these substitutions might have on resistance against INSTIs. E138K is a common secondary substitution observed with various primary resistance substitutions in RAL- and EVG-treated individuals. Viral infectivity, replicative capacity, and resistance against INSTIs were measured in cell-based assays. Strand transfer and 3' processing activities were measured biochemically. The combination of the R263K and T66I substitutions decreased HIV-1 infectivity, replicative capacity, and strand transfer activity. The addition of the E138K substitution partially compensated for these deficits and resulted in high levels of resistance against EVG but not against DTG or RAL. These findings suggest that the presence of the T66I substitution will not compromise the activity of DTG and may also help to prevent the additional generation of the R263K mutation. Our observations support the use of DTG in second-line therapy for individuals who experience treatment failure with EVG due to the T66I substitution. IMPORTANCE The integrase strand transfer inhibitors (INSTIs) elvitegravir and dolutegravir are newly developed inhibitors against human immunodeficiency virus type 1 (HIV-1). HIV drug-resistant mutations in integrase that can arise in individuals treated with elvitegravir commonly include the T66I substitution, whereas R263K is a signature resistance substitution against dolutegravir. In order to determine how different combinations of integrase resistance mutations can influence the outcome of therapy, we report here the effects of the T66I, E138K, and R263K substitutions, alone and in combination, on viral replicative capacity and resistance to integrase inhibitors. Our results show that the addition of R263K to the T66I substitution diminishes viral replicative capacity and strand transfer activity while not compromising susceptibility to dolutegravir. This supports the use of dolutegravir in second-line therapy for patients failing elvitegravir therapy who harbor the T66I resistance substitution.

Description: CYP153, one of the most common medium-chain n -alkane hydroxylases belonging to the cytochrome P450 superfamily, is widely expressed in n -alkane-degrading bacteria. CYP153 is also thought to cooperate with AlkB in degrading various n -alkanes. However, the mechanisms regulating the expression of the protein remain largely unknown. In this paper, we studied CYP153 gene transcription regulation by the potential AraC family regulator (CypR) located upstream of the CYP153 gene cluster in a broad-spectrum n -alkane-degrading Gram-positive bacterium, Dietzia sp. strain DQ12-45-1b. We first identified the transcriptional start site and the promoter of the CYP153 gene cluster. Sequence alignment of upstream regions of CYP153 gene clusters revealed high conservation in the –10 and –35 regions in Actinobacteria . Further analysis of the β-galactosidase activity in the CYP153 gene promoter- lacZ fusion cell indicated that the CYP153 gene promoter was induced by n -alkanes comprised of 8 to 14 carbon atoms, but not by derived decanol and decanic acid. Moreover, we constructed a cypR mutant strain and found that the CYP153 gene promoter activities and CYP153 gene transcriptional levels in the mutant strain were depressed compared with those in the wild-type strain in the presence of n -alkanes, suggesting that CypR served as an activator for the CYP153 gene promoter. By comparing CYP153 gene arrangements in Actinobacteria and Proteobacteria , we found that the AraC family regulator is ubiquitously located upstream of the CYP153 gene, suggesting its universal regulatory role in CYP153 gene transcription. We further hypothesize that the observed mode of CYP153 gene regulation is shared by many Actinobacteria .

Description: Brucella abortus and Yersinia enterocolitica serotype O:9 serologically cross-react in the immune response with the host; therefore, our aim was to compare the immune responses to these two pathogens. We selected typical B. abortus and Y. enterocolitica O:9 strains to study the cytokine immune response and the histopathological changes in livers and spleens of BALB/c mice. The data showed the cytokine responses to the two strains of pathogens were different, where the average levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), gamma interferon (IFN-), interleukin-12 (IL-12), and tumor necrosis factor alpha (TNF-α) were higher with B. abortus infections than with Y. enterocolitica O:9 infections, especially for IFN-, while the IL-10 level was lower and the levels of IL-1β, IL-4, IL-5, and IL-6 were similar. The histopathological effects in the livers and spleens of the BALB/c mice with B. abortus and Y. enterocolitica O:9 infections were similar; however, the pathological changes in the liver were greater with B. abortus infections, while damage in the spleen was greater with Y. enterocolitica O:9 infections. These observations show that different cytokine responses and histopathological changes occur with B. abortus and Y. enterocolitica O:9 infections.

Description: Nanomaterials have the characteristics associated with high surface-to-volume ratios and have been explored for their antiviral activity. Despite some success, cytotoxicity has been an issue in nanomaterial-based antiviral strategies. We previously developed a novel method to fully exfoliate montmorillonite clay to generate the most fundamental units of nanoscale silicate platelet (NSP). We further modified NSP by capping with various surfactants and found that the surfactant-modified NSP (NSQ) was less cytotoxic. In this study, we tested the antiviral potentials of a series of natural-clay-derived nanomaterials. Among the derivatives, NSP modified with anionic sodium dodecyl sulfate (NSQc), but not the pristine clay, unmodified NSP, a silver nanoparticle-NSP hybrid, NSP modified with cationic n -octadecanylamine hydrochloride salt, or NSP modified with nonionic Triton X-100, significantly suppressed the plaque-forming ability of Japanese encephalitis virus (JEV) at noncytotoxic concentrations. NSQc also blocked infection with dengue virus (DEN) and influenza A virus. Regarding the antiviral mechanism, NSQc interfered with viral binding through electrostatic interaction, since its antiviral activity can be neutralized by Polybrene, a cationic polymer. Furthermore, NSQc reduced the lethality of JEV and DEN infection in mouse challenge models. Thus, the surfactant-modified exfoliated nanoclay NSQc may be a novel nanomaterial with broad and potent antiviral activity. IMPORTANCE Nanomaterials have being investigated as antimicrobial agents, yet their antiviral potential is overshadowed by their cytotoxicity. By using a novel method, we fully exfoliated montmorillonite clay to generate the most fundamental units of nanoscale silicate platelet (NSP). Here, we show that the surfactant-modified NSP (NSQ) is less cytotoxic and that NSQc (NSP modified with sodium dodecyl sulfate) could potently block infection by dengue virus (DEN), Japanese encephalitis virus (JEV), and influenza A virus at noncytotoxic concentrations. For the antiviral mechanism, we find that the electrostatic interaction between the negatively charged NSQc and the positively charged virus particles blocks viral binding. Furthermore, we used mouse challenge models of JEV and DEN to demonstrate the in vivo antiviral potential of NSQc. Thus, NSQc may function as a potent and safe antiviral nanohybrid against several viruses, and our success in synthesizing surfactant-modified NSP with antiviral activity may shed some light on future antiviral development.

Description: n -Alkanes are ubiquitous in nature and are widely used by microorganisms as carbon sources. Alkane hydroxylation by alkane monooxygenases is a critical step in the aerobic biodegradation of n -alkanes, which plays important roles in natural alkane attenuation and is used in industrial and environmental applications. The alkane oxidation operon, alkW1-alkX , in the alkane-degrading strain Dietzia sp. strain DQ12-45-1b is negatively autoregulated by the TetR family repressor AlkX via a product positive feedback mechanism. To predict the gene regulation mechanism, we determined the 3.1-Å crystal structure of an AlkX homodimer in a non-DNA-bound state. The structure showed traceable long electron density deep inside a hydrophobic cavity of each monomer along the long axis of the helix bundle, and further gas chromatography-mass spectrometry analysis of AlkX revealed that it contained the Escherichia coli -derived long-chain fatty acid molecules as a ligand. Moreover, an unusual structural feature of AlkX is an extra helix, α6', forming a lid-like structure with α6 covering the inducer-binding pocket and occupying the space between the two symmetrical DNA-binding motifs in one dimer, indicating a distinct conformational transition mode in modulating DNA binding. Sequence alignment of AlkX homologs from Dietzia strains showed that the residues involved in DNA and inducer binding are highly conserved, suggesting that the regulation mechanisms of n -alkane hydroxylation are possibly a common characteristic of Dietzia strains. IMPORTANCE With n -alkanes being ubiquitous in nature, many bacteria from terrestrial and aquatic environments have evolved n -alkane oxidation functions. Alkane hydroxylation by alkane monooxygenases is a critical step in the aerobic biodegradation of n -alkanes, which plays important roles in natural alkane attenuation and petroleum-contaminating environment bioremediation. The gene regulation of the most common alkane hydroxylase, AlkB, has been studied widely in Gram-negative bacteria but has been less explored in Gram-positive bacteria. Our previous study showed that the TetR family regulator (TFR) AlkX negatively autoregulated the alkane oxidation operon, alkW1-alkX , in the Gram-positive strain Dietzia sp. strain DQ12-45-1b. Although TFRs are one of the most common transcriptional regulator families in bacteria, the TFR involved in n -alkane metabolism has been reported only recently. In this study, we determined the crystal structure of AlkX, which implies a distinct DNA/ligand binding mode. Our results shed light upon the regulation mechanism of the common alkane degradation process in nature.

Description: Objectives The primary healthcarecentre (PHCC) is the first place that medical students experience patient contact. Usually, medical students are frustrated by a lack of proper skills training for on-campus history taking (HT), physical examination (PE) and self-directed learning (SDL) to prepare for their PHCC and inhospital patient contact. For pre-clerks, this study aims to compare the effectiveness of PHCC training and PHCC training in combination with on-campus HT and PE training modules (PHCC+on-campus) on their clerkship preparedness. Design This comparative study utilised prospective, consecutive, end of pre-clerkship group objective structured clinical examination (GOSCE), beginning of clerkship OSCE and self-administered Preparation for Hospital Practice Questionnaire (PHPQ). Setting/participants 128 pre-clinical clerk volunteers (64 each year) receiving PHCC training (7 week PHCCtraining in addition to 7 week assignment based group learning, academic year 2014, controls) and PHCC training in combination with on-campus module training (academic year 2015, 7 week PHCCtraining in addition to 7 week on-campus sessions) were sequentially assessed before the module (week 1), at the end of the module (week 14) and at the beginning of clerkship (week 25). Results For overall HT and PE skills, both PHCC and PHCC+on-campus module trained pre-clerks performed better on OSCE than GOSCE. Additionally, the improvement was accompanied by higher self-reported PHPQ scores in ‘confidence/coping’ and ‘SDL’ domains. At the end of the pre-clerkship and the beginning of the clerkship stages, the degree of improvement in preparedness in ‘confidence/coping’ and ‘SDL’ domains was higher for those in the PHCC+on-campus group than for those in the PHCC group. Among the PHCC+on-campus module participants, a positive association was observed between high mean PHPQ-SDL scores and high OSCE scores. Conclusions Our study suggests that the PHCC+on-campus module, which is paired faculty led and pre-trained dyad student assisted, is effective in developing a preclinical clerk’s HT and PE skills and intensifying SDL/patient management abilities to prepare for hospital practice in clerkship.

Description: Objectives Inter-professional education (IPE) builds inter-professional collaboration (IPC) attitude/skills of health professionals. This interventional IPE programme evaluates whether benchmarking sharing can successfully cultivate seed instructors responsible for improving their team members’ IPC attitudes. Design Prospective, pre-post comparative cross-sectional pilot study. Setting/participants Thirty four physicians, 30 nurses and 24 pharmacists, who volunteered to be trained as seed instructors participated in 3.5-hour preparation and 3.5-hour simulation courses. Then, participants (n=88) drew lots to decide 44 presenters, half of each profession, who needed to prepare IPC benchmarking and formed Group 1. The remaining participants formed Group 2 (regular). Facilitators rated the Group 1 participants’ degree of appropriate transfer and sustainable practice of the learnt IPC skills in the workplace according to successful IPC examples in their benchmarking sharing. Results For the three professions, improvement in IPC attitude was identified by sequential increase in the post-course (second month, T 2 ) and end-of-study (third month, T 3 ) Interdisciplinary Education Perception Scale (IEPS) and Attitudes Towards Healthcare Teams Scale (ATHCTS) scores, compared with pre-course (first month, T 1 ) scores. By IEPS and ATHCTS-based assessment, the degree of sequential improvements in IPC attitude was found to be higher among nurses and pharmacists than in physicians. In benchmarking sharing, the facilitators’ agreement about the degree of participants’appropriate transfer and sustainable practice learnt ‘communication and teamwork’ skills in the workplace were significantly higher among pharmacists and nurses than among physicians. The post-intervention random sampling survey (sixth month, T post ) found that the IPC attitude of the three professions improved after on-site IPC skill promotion by new programme-trained seed instructors within teams. Conclusions Addition of benchmark sharing to a diamond-based IPE simulation programme enhances participants’ IPC attitudes, self-reflection, workplace transfer and practice of the learnt skills. Furthermore, IPC promotion within teams by newly trained seed instructors improved the IPC attitudes across all three professions.

Description: Introduction Up to half of all smokers develop clinically significant chronic obstructive pulmonary disease (COPD). Gaps exist in the implementation and uptake of evidence-based guidelines for managing COPD in primary care. We describe the methodology of a cluster randomised controlled trial (cRCT) evaluating the efficacy and cost-effectiveness of an interdisciplinary model of care aimed at reducing the burden of smoking and COPD in Australian primary care settings. Methods and analysis A cRCT is being undertaken to evaluate an interdisciplinary model of care (RADICALS — Review of Airway Dysfunction and Interdisciplinary Community-based care of Adult Long-term Smokers). General practice clinics across Melbourne, Australia, are identified and randomised to the intervention group (RADICALS) or usual care. Patients who are current or ex-smokers, of at least 10 pack years, including those with an existing diagnosis of COPD, are being recruited to identify 280 participants with a spirometry-confirmed diagnosis of COPD. Handheld lung function devices are being used to facilitate case-finding. RADICALS includes individualised smoking cessation support, home-based pulmonary rehabilitation and home medicines review. Patients at control group sites receive usual care and Quitline referral, as appropriate. Follow-ups occur at 6 and 12 months from baseline to assess changes in quality of life, abstinence rates, health resource utilisation, symptom severity and lung function. The primary outcome is change in St George’s Respiratory Questionnaire score of patients with COPD at 6 months from baseline. Ethics and dissemination This project has been approved by the Monash University Human Research Ethics Committee and La Trobe University Human Ethics Committee (CF14/1018 – 2014000433). Results of the study will be disseminated in peer-reviewed journals and research conferences. If the intervention is successful, the RADICALS programme could potentially be integrated into general practices across Australia and sustained over time. Trial registration number ACTRN12614001155684; Pre-results.

Description: High-precision measurements of size changes of individual bacterial spores based on ellipse fitting to bright-field images recorded with a digital camera were employed to monitor the germination of Bacillus spores with a precision of ~5 nm. To characterize the germination of individual spores, we recorded bright-field and phase-contrast images and found that the timing of changes in their normalized intensities coincided, so the bright-field images can be used to characterize spore size and refractility changes during germination. The major conclusions from this work were as follows. (i) The sizes of germinating B. cereus spores were nearly unchanged until T release , the time of the completion of CaDPA (a 1:1 chelate of Ca 2+ and dipicolinic acid [DPA]) release after addition of nutrient germinants. (ii) The minor axis of germinating B. cereus spores rapidly increased by ~50 nm in a few seconds right after T release , while the major axis was slightly decreased or unchanged. Both the minor and major axes remained unchanged for a further 30 to 45 s and then increased by 100 to 200 nm by T lys , the time of completion of cortex lysis. (iii) Individual spores in a population showed significant heterogeneity in the timing of germination events, such as T release and T lys , but also variation in size changes during germination. (iv) Bacillus subtilis wild-type spores, B. subtilis spores lacking the cortex-lytic enzyme CwlJ, and wild-type Bacillus megaterium spores showed similar kinetics of size changes during nutrient germination. The size increases in germinating spores probably result from uptake of water and cortex lysis after completion of CaDPA release.

Description: The viral ribonucleoprotein (vRNP) complex of influenza A viruses (IAVs) contains an RNA-dependent RNA polymerase complex (RdRp) and nucleoprotein (NP) and is the functional unit for viral RNA transcription and replication. The vRNP complex is an important determinant of virus pathogenicity and host adaptation, implying that its function can be affected by host factors. In our study, we identified host protein Moloney leukemia virus 10 (MOV10) as an inhibitor of IAV replication, since depletion of MOV10 resulted in a significant increase in virus yield. MOV10 inhibited the polymerase activity in a minigenome system through RNA-mediated interaction with the NP subunit of vRNP complex. Importantly, we found that the interaction between MOV10 and NP prevented the binding of NP to importin-α, resulting in the retention of NP in the cytoplasm. Both the binding of MOV10 to NP and its inhibitory effect on polymerase activity were independent of its helicase activity. These results suggest that MOV10 acts as an anti-influenza virus factor through specifically inhibiting the nuclear transportation of NP and subsequently inhibiting the function of the vRNP complex. IMPORTANCE The interaction between the influenza virus vRNP complex and host factors is a major determinant of viral tropism and pathogenicity. Our study identified MOV10 as a novel host restriction factor for the influenza virus life cycle since it inhibited the viral growth rate. Conversely, importin-α has been shown as a determinant for influenza tropism and a positive regulator for viral polymerase activity in mammalian cells but not in avian cells. MOV10 disrupted the interaction between NP and importin-α, suggesting that MOV10 could also be an important host factor for influenza virus transmission and pathogenicity. Importantly, as an interferon (IFN)-inducible protein, MOV10 exerted a novel mechanism for IFNs to inhibit the replication of influenza viruses. Furthermore, our study potentially provides a new drug design strategy, the use of molecules that mimic the antiviral mechanism of MOV10.