Amsterdam's Schiphol Airport was closed briefly as police investigated a suspicious situation. Julie Noce reports.

While an alarming 9 per cent of insects on land are being lost each decade, the state of the world’s insects is much more nuanced than warnings of an insect apocalypse

Title: Secondhand Smoke Blocks Artery Repair
Category: Health News
Created: 4/30/2008 2:00:00 AM
Last Editorial Review: 4/30/2008 12:00:00 AM

Title: Secondhand Smoke Permeates Many Apartment Buildings: Study
Category: Health News
Created: 4/29/2012 10:05:00 AM
Last Editorial Review: 4/30/2012 12:00:00 AM

Title: Many Asthmatic Kids Harmed by Secondhand Smoke: Study
Category: Health News
Created: 5/1/2012 10:05:00 AM
Last Editorial Review: 5/1/2012 12:00:00 AM

Title: Second Man Arrested in Tainted Letter Case, Officials Report
Category: Health News
Created: 4/27/2013 6:35:00 PM
Last Editorial Review: 4/29/2013 12:00:00 AM

Title: Secondhand Smoke Tied to Lower 'Good' Cholesterol in Teen Girls
Category: Health News
Created: 4/30/2013 2:35:00 PM
Last Editorial Review: 5/1/2013 12:00:00 AM

Title: Keep Prescription Drugs Secure From Teens: Expert
Category: Health News
Created: 4/25/2014 2:35:00 PM
Last Editorial Review: 4/28/2014 12:00:00 AM

Title: Induced Labor May Lower Risk for C-Section, Study Finds
Category: Health News
Created: 4/28/2014 12:35:00 PM
Last Editorial Review: 4/29/2014 12:00:00 AM

Title: C-Section Rates Drop Slightly With Hospital Review Program
Category: Health News
Created: 4/29/2015 12:00:00 AM
Last Editorial Review: 4/30/2015 12:00:00 AM

Title: Was Dyslexia the Secret to Leonardo da Vinci's Greatness?
Category: Health News
Created: 5/2/2019 12:00:00 AM
Last Editorial Review: 5/3/2019 12:00:00 AM

Title: Do C-Section Babies Become Heavier Adults?
Category: Health News
Created: 4/14/2020 12:00:00 AM
Last Editorial Review: 4/15/2020 12:00:00 AM

Title: Necklace Spots A-Fib in Just Over 30 Seconds
Category: Health News
Created: 5/6/2020 12:00:00 AM
Last Editorial Review: 5/7/2020 12:00:00 AM

A necklace outfitted with a high-tech pendant may be able to screen for signs of an abnormal heart rhythm condition known as atrial fibrillation.

Title: Herpes Virus Yields Up Genetic Secrets
Category: Health News
Created: 4/29/2020 12:00:00 AM
Last Editorial Review: 4/30/2020 12:00:00 AM

Title: Second HIV Patient Reportedly 'Cured'
Category: Health News
Created: 3/9/2020 12:00:00 AM
Last Editorial Review: 3/10/2020 12:00:00 AM

Title: 4 in 10 Security Guards Suffer PTSD, Study Finds
Category: Health News
Created: 4/14/2020 12:00:00 AM
Last Editorial Review: 4/15/2020 12:00:00 AM

Title: Solosec (secnidazole)
Category: Medications
Created: 4/17/2020 12:00:00 AM
Last Editorial Review: 4/17/2020 12:00:00 AM

Title: Tukysa Approved for Unresectable, Metastatic HER2-Positive Breast Cancer
Category: Health News
Created: 4/20/2020 12:00:00 AM
Last Editorial Review: 4/21/2020 12:00:00 AM

ABSTRACT

Human noroviruses (HuNoVs) are the leading cause of nonbacterial gastroenteritis worldwide. Histo-blood group antigen (HBGA) expression is an important susceptibility factor for HuNoV infection based on controlled human infection models and epidemiologic studies that show an association of secretor status with infection caused by several genotypes. The fucosyltransferase 2 gene (FUT2) affects HBGA expression in intestinal epithelial cells; secretors express a functional FUT2 enzyme, while nonsecretors lack this enzyme and are highly resistant to infection and gastroenteritis caused by many HuNoV strains. These epidemiologic associations are confirmed by infections in stem cell-derived human intestinal enteroid (HIE) cultures. GII.4 HuNoV does not replicate in HIE cultures derived from nonsecretor individuals, while HIEs from secretors are permissive to infection. However, whether FUT2 expression alone is critical for infection remains unproven, since routinely used secretor-positive transformed cell lines are resistant to HuNoV replication. To evaluate the role of FUT2 in HuNoV replication, we used CRISPR or overexpression to genetically manipulate FUT2 gene function to produce isogenic HIE lines with or without FUT2 expression. We show that FUT2 expression alone affects both HuNoV binding to the HIE cell surface and susceptibility to HuNoV infection. These findings indicate that initial binding to a molecule(s) glycosylated by FUT2 is critical for HuNoV infection and that the HuNoV receptor is present in nonsecretor HIEs. In addition to HuNoV studies, these isogenic HIE lines will be useful tools to study other enteric microbes where infection and/or disease outcome is associated with secretor status.

IMPORTANCE Several studies have demonstrated that secretor status is associated with susceptibility to human norovirus (HuNoV) infection; however, previous reports found that FUT2 expression is not sufficient to allow infection with HuNoV in a variety of continuous laboratory cell lines. Which cellular factor(s) regulates susceptibility to HuNoV infection remains unknown. We used genetic manipulation of HIE cultures to show that secretor status determined by FUT2 gene expression is necessary and sufficient to support HuNoV replication based on analyses of isogenic lines that lack or express FUT2. Fucosylation of HBGAs is critical for initial binding and for modification of another putative receptor(s) in HIEs needed for virus uptake or uncoating and necessary for successful infection by GI.1 and several GII HuNoV strains.

ABSTRACT

The global stress response controlled by the alternative sigma factor RpoS protects enteric bacteria from a variety of environmental stressors. The role of RpoS in other, nonenteric bacteria, such as the opportunistic pathogen Pseudomonas aeruginosa, is less well understood. Here, we employed experimental social evolution to reveal that cooperative behavior via secreted public goods is an important function in the RpoS response of P. aeruginosa. Using whole-genome sequencing, we identified rpoS loss-of-function mutants among isolates evolved in a protein growth medium that requires extracellular proteolysis. We found that rpoS mutants comprise up to 25% of the evolved population and that they behave as social cheaters, with low fitness in isolation but high fitness in mixed culture with the cooperating wild type. We conclude that rpoS mutants cheat because they exploit an RpoS-controlled public good produced by the wild type, the secreted aminopeptidase PaAP, and because they do not carry the metabolic costs of expressing PaAP and many other gene products in the large RpoS regulon. Our results suggest that PaAP is an integral part of a proteolytic sequence in P. aeruginosa that permits the utilization of protein as a nutrient source. Our work broadens the scope of stress response functions in bacteria.

IMPORTANCE Bacterial stress responses are generally considered protective measures taken by individual cells. Enabled by an experimental evolution approach, we describe a contrasting property, collective nutrient acquisition, in the RpoS-dependent stress response of the opportunistic human pathogen P. aeruginosa. Specifically, we identify the secreted P. aeruginosa aminopeptidase (PaAP) as an essential RpoS-controlled function in extracellular proteolysis. As a secreted "public good," PaAP permits cheating by rpoS mutants that save the metabolic costs of expressing RpoS-controlled genes dispensable under the given growth conditions. Proteolytic enzymes are important virulence factors in P. aeruginosa pathogenesis and constitute a potential target for antimicrobial therapy. More broadly, our work contributes to recent findings in higher organisms that stress affects not only individual fitness and competitiveness but also cooperative behavior.

ABSTRACT

Mobile elements—plasmids and phages—are important components of microbial function and evolution via traits that they encode and their capacity to shuttle genetic material between species. We here report the unusually rich array of mobile elements within the genome of Arsenophonus nasoniae, the son-killer symbiont of the parasitic wasp Nasonia vitripennis. This microbe’s genome has the highest prophage complement reported to date, with over 50 genomic regions that represent either intact or degraded phage material. Moreover, the genome is predicted to include 17 extrachromosomal genetic elements, which carry many genes predicted to be important at the microbe-host interface, derived from a diverse assemblage of insect-associated gammaproteobacteria. In our system, this diversity was previously masked by repetitive mobile elements that broke the assembly derived from short reads. These findings suggest that other complex bacterial genomes will be revealed in the era of long-read sequencing.

IMPORTANCE The biology of many bacteria is critically dependent on genes carried on plasmid and phage mobile elements. These elements shuttle between microbial species, thus providing an important source of biological innovation across taxa. It has recently been recognized that mobile elements are also important in symbiotic bacteria, which form long-lasting interactions with their host. In this study, we report a bacterial symbiont genome that carries a highly complex array of these elements. Arsenophonus nasoniae is the son-killer microbe of the parasitic wasp Nasonia vitripennis and exists with the wasp throughout its life cycle. We completed its genome with the aid of recently developed long-read technology. This assembly contained over 50 chromosomal regions of phage origin and 17 extrachromosomal elements within the genome, encoding many important traits at the host-microbe interface. Thus, the biology of this symbiont is enabled by a complex array of mobile elements.

ABSTRACT

Intracellular bacterial pathogens remodel cellular functions during their infectious cycle via the coordinated actions of effector molecules delivered through dedicated secretion systems. While the function of many individual effectors is known, how they interact to promote pathogenesis is rarely understood. The zoonotic bacterium Brucella abortus, the causative agent of brucellosis, delivers effector proteins via its VirB type IV secretion system (T4SS) which mediate biogenesis of the endoplasmic reticulum (ER)-derived replicative Brucella-containing vacuole (rBCV). Here, we show that T4SS effectors BspB and RicA display epistatic interactions in Brucella replication. Defects in rBCV biogenesis and Brucella replication caused by deletion of bspB were dependent on the host GTPase Rab2a and suppressed by the deletion of ricA, indicating a role of Rab2-binding effector RicA in these phenotypic defects. Rab2a requirements for rBCV biogenesis and Brucella intracellular replication were abolished upon deletion of both bspB and ricA, demonstrating that the functional interaction of these effectors engages Rab2-dependent transport in the Brucella intracellular cycle. Expression of RicA impaired host secretion and caused Golgi fragmentation. While BspB-mediated changes in ER-to-Golgi transport were independent of RicA and Rab2a, BspB-driven alterations in Golgi vesicular traffic also involved RicA and Rab2a, defining BspB and RicA’s functional interplay at the Golgi interface. Altogether, these findings support a model where RicA modulation of Rab2a functions impairs Brucella replication but is compensated by BspB-mediated remodeling of Golgi apparatus-associated vesicular transport, revealing an epistatic interaction between these T4SS effectors.

IMPORTANCE Bacterial pathogens with an intracellular lifestyle modulate many host cellular processes to promote their infectious cycle. They do so by delivering effector proteins into host cells via dedicated secretion systems that target specific host functions. While the roles of many individual effectors are known, how their modes of action are coordinated is rarely understood. Here, we show that the zoonotic bacterium Brucella abortus delivers the BspB effector that mitigates the negative effect on bacterial replication that the RicA effector exerts via modulation of the host small GTPase Rab2. These findings provide an example of functional integration between bacterial effectors that promotes proliferation of pathogens.

I’ve been talking a lot lately about the importance of working across sectors for public health — of not going it alone to tackle the imposing challenges before us. The ideal public health team is broad and includes not only public health professionals representing the essential services, but also professionals from other disciplines, the general public and students of all stripes.

With rising costs and below-average outcomes, North Carolina's health care value proposition is upside down. It's time for employers to lead transformative change.

A growing number of small secreted peptides (SSPs) in plants are recognized as important regulatory molecules with roles in processes such as growth, development, reproduction, stress tolerance, and pathogen defense. Recent discoveries further implicate SSPs in regulating root nodule development, which is of particular significance for legumes. SSP-coding genes are frequently overlooked, because genome annotation pipelines generally ignore small open reading frames, which are those most likely to encode SSPs. Also, SSP-coding small open reading frames are often expressed at low levels or only under specific conditions, and thus are underrepresented in non-tissue-targeted or non-condition-optimized RNA-sequencing projects. We previously identified 4,439 SSP-encoding genes in the model legume Medicago truncatula. To support systematic characterization and annotation of these putative SSP-encoding genes, we developed the M. truncatula Small Secreted Peptide Database (MtSSPdb; https://mtsspdb.noble.org/). MtSSPdb currently hosts (1) a compendium of M. truncatula SSP candidates with putative function and family annotations; (2) a large-scale M. truncatula RNA-sequencing-based gene expression atlas integrated with various analytical tools, including differential expression, coexpression, and pathway enrichment analyses; (3) an online plant SSP prediction tool capable of analyzing protein sequences at the genome scale using the same protocol as for the identification of SSP genes; and (4) information about a library of synthetic peptides and root and nodule phenotyping data from synthetic peptide screens in planta. These datasets and analytical tools make MtSSPdb a unique and valuable resource for the plant research community. MtSSPdb also has the potential to become the most complete database of SSPs in plants.

Jonathan M. Whittamore

Oxalate is a common constituent of kidney stones but the mechanism of its transport across epithelia are not well understood. With prior research on the role of the intestine focused on mammals this study considered oxalate handling by teleost fish. Given the osmotic challenge of seawater (SW), teleosts have limited scope for urinary oxalate excretion relative to freshwater (FW). The marine teleost intestine was hypothesized as the principal route for oxalate elimination thus demanding epithelial secretion. To test this, intestinal ¹⁴C-oxalate flux was compared between FW- and SW-acclimated sailfin molly (Poecilia latipinna). In SW, oxalate was secreted at remarkable rates (367.90±22.95 pmol cm^–2 h^–1) which were similar following FW transfer (387.59±27.82 pmol cm^–2 h^–1), implying no regulation by salinity. Nevertheless, this ability to secrete oxalate 15-19 times higher than mammalian small intestine supports this proposal of the teleost gut as a previously unrecognized excretory pathway.

Qingxiang Guo, Yang Liu, Yanhua Zhai, and Zemao Gu

Disassembling the parasitic spores and acquiring the main subunits is a prerequisite for deep understanding of the basic biology of parasites. Herein we present a fast and efficient method to dissect the myxospores in a few steps, which mainly involved sonication, sucrose density gradient and Percoll density gradient. We tested our method on three myxozoans species and demonstrated this method allows the dismembering of myxospores, isolation of intact and clean nematocysts and shell valves within 2h by low-cost. This new tool will facilitate subsequent analyses and enable a better understanding of the ecological and evolutionary significance of parasitic spores.

Simon Tapper, Joseph J. Nocera, and Gary Burness

Climatic warming is predicted to increase the frequency of extreme weather events, which may reduce an individual's capacity for sustained activity due to thermal limits. We tested whether the risk of overheating may limit parental provisioning of an aerial insectivorous bird in population decline. For many seasonally breeding birds, parents are thought to operate close to an energetic ceiling during the 2-3 week chick-rearing period. The factors determining the ceiling remain unknown, although it may be set by an individual's capacity to dissipate body heat (the heat dissipation limitation hypothesis). Over two breeding seasons we experimentally trimmed the ventral feathers of female tree swallows (Tachycineta bicolor, Vieillot, 1808) to provide a thermal window. We then monitored maternal and paternal provisioning rates, nestling growth rates, and fledging success. We found the effect of our experimental treatment was context-dependent. Females with an enhanced capacity to dissipate heat fed their nestlings at higher rates than controls when conditions were hot, but the reverse was true under cool conditions. Control females and their mates both reduced foraging under hot conditions. In contrast, male partners of trimmed females maintained a constant feeding rate across temperatures, suggesting attempts to match the feeding rate of their partners. On average, nestlings of trimmed females were heavier than controls, but did not have a higher probability of fledging. We suggest that removal of a thermal constraint allowed females to increase provisioning rates, but additionally provided nestlings with a thermal advantage via increased heat transfer during maternal brooding. Our data provide support for the heat dissipation limitation hypothesis and suggest that depending on temperature, heat dissipation capacity can influence reproductive success in aerial insectivores.

Jack Nguyen and Meir M. Barak

Cortical bone remodeling is an ongoing process triggered by microdamage, where osteoclasts resorb existing bone and osteoblasts deposit new bone in the form of secondary osteons (Haversian systems). Previous studies revealed regional variance in Haversian systems structure and possibly material, between opposite cortices of the same bone. As bone mechanical properties depend on tissue structure and material, it is predicted that bone mechanical properties will vary in accordance with structural and material regional heterogeneity. To test this hypothesis, we analyzed the structure, mineral content and compressive stiffness of secondary bone from the cranial and caudal cortices of the white-tailed deer proximal humerus. We found significantly larger Haversian systems and canals in the cranial cortex but no significant difference in mineral content between the two cortices. Accordingly, we found no difference in compressive stiffness between the two cortices and thus our working hypothesis was rejected. Seeing that the deer humerus is curved and thus likely subjected to bending during habitual locomotion, we expect that similar to other curved long bones, the cranial cortex of the deer humerus is likely subjected primarily to tensile strains and the caudal cortex is likely subject primarily to compressive strains. Consequently, our results suggest that strain magnitude (larger in compression) and sign (compression vs. tension) affect differently the osteoclasts and osteoblasts in the BMU. Our results further suggest that osteoclasts are inhibited in regions of high compressive strains (creating smaller Haversian systems) while osteoblasts’ osteoid deposition and mineralization is not affected by strain magnitude and sign.

Background

Canagliflozin reduced renal and cardiovascular events in people with type 2 diabetes in the CREDENCE trial. We assessed efficacy and safety of canagliflozin by initial estimated glomerular filtration rate (eGFR).

Background

Experimental and observational studies have raised concerns that giving intravenous (IV) iron to patients, such as individuals receiving maintenance hemodialysis, might increase the risk of infections. The Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL) trial randomized 2141 patients undergoing maintenance hemodialysis for ESKD to a high-dose or a low-dose IV iron regimen, with a primary composite outcome of all-cause death, heart attack, stroke, or hospitalization for heart failure. Comparison of infection rates between the two groups was a prespecified secondary analysis.

Axonal protein synthesis has been shown to play a role in developmental and regenerative growth, as well as in the maintenance of the axoplasm in a steady state. Recent studies have begun to identify the mRNAs localized in axons, which could be translated locally under different conditions. Despite that by now hundreds or thousands of mRNAs have been shown to be localized into the axonal compartment of cultured neurons in vitro, knowledge of which mRNAs are localized in mature myelinated axons is quite limited. With the purpose of characterizing the transcriptome of mature myelinated motor axons of peripheral nervous systems, we modified the axon microdissection method devised by Koenig, enabling the isolation of the axoplasm RNA to perform RNA-seq analysis. The transcriptome analysis indicates that the number of RNAs detected in mature axons is lower in comparison with in vitro data, depleted of glial markers, and enriched in neuronal markers. The mature myelinated axons are enriched for mRNAs related to cytoskeleton, translation, and oxidative phosphorylation. Moreover, it was possible to define core genes present in axons when comparing our data with transcriptomic data of axons grown in different conditions. This work provides evidence that axon microdissection is a valuable method to obtain genome-wide data from mature and myelinated axons of the peripheral nervous system, and could be especially useful for the study of axonal involvement in neurodegenerative pathologies of motor neurons such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophies (SMA).

The heterodimeric cytokine interleukin-23 (IL-23 or IL23A/IL12B) is produced by dendritic cells and macrophages and promotes the proinflammatory and regenerative activities of T helper 17 (Th17) and innate lymphoid cells. A recent study has reported that IL-23 is also secreted by lung adenoma cells and generates an inflammatory and immune-suppressed stroma. Here, we observed that proinflammatory tumor necrosis factor (TNF)/NF-κB and mitogen-activated protein kinase (MAPK) signaling strongly induce IL23A expression in intestinal epithelial cells. Moreover, we identified a strong crosstalk between the NF-κB and MAPK/ERK kinase (MEK) pathways, involving the formation of a transcriptional enhancer complex consisting of proto-oncogene c-Jun (c-Jun), RELA proto-oncogene NF-κB subunit (RelA), RUNX family transcription factor 1 (RUNX1), and RUNX3. Collectively, these proteins induced IL23A secretion, confirmed by immunoprecipitation of endogenous IL23A from activated human colorectal cancer (CRC) cell culture supernatants. Interestingly, IL23A was likely secreted in a noncanonical form, as it was not detected by an ELISA specific for heterodimeric IL-23 likely because IL12B expression is absent in CRC cells. Given recent evidence that IL23A promotes tumor formation, we evaluated the efficacy of MAPK/NF-κB inhibitors in attenuating IL23A expression and found that the MEK inhibitor trametinib and BAY 11–7082 (an IKKα/IκB inhibitor) effectively inhibited IL23A in a subset of human CRC lines with mutant KRAS or BRAFV600E mutations. Together, these results indicate that proinflammatory and mitogenic signals dynamically regulate IL23A in epithelial cells. They further reveal its secretion in a noncanonical form independent of IL12B and that small-molecule inhibitors can attenuate IL23A secretion.

Negative circumferential resection margins (CRM) are the cornerstone for the curative treatment of locally advanced rectal cancer (LARC). However, in up to 18.6% of patients, tumor-positive resection margins are detected on histopathology. In this proof-of-concept study, we investigated the feasibility of optical molecular imaging as a tool for evaluating the CRM directly after surgical resection to improve tumor-negative CRM rates. Methods: LARC patients treated with neoadjuvant chemoradiotherapy received an intravenous bolus injection of 4.5 mg of bevacizumab-800CW, a fluorescent tracer targeting vascular endothelial growth factor A, 2–3 d before surgery (ClinicalTrials.gov identifier: NCT01972373). First, for evaluation of the CRM status, back-table fluorescence-guided imaging (FGI) of the fresh surgical resection specimens (n = 8) was performed. These results were correlated with histopathology results. Second, for determination of the sensitivity and specificity of bevacizumab-800CW for tumor detection, a mean fluorescence intensity cutoff value was determined from the formalin-fixed tissue slices (n = 42; 17 patients). Local bevacizumab-800CW accumulation was evaluated by fluorescence microscopy. Results: Back-table FGI correctly identified a tumor-positive CRM by high fluorescence intensities in 1 of 2 patients (50%) with a tumor-positive CRM. For the other patient, low fluorescence intensities were shown, although (sub)millimeter tumor deposits were present less than 1 mm from the CRM. FGI correctly identified 5 of 6 tumor-negative CRM (83%). The 1 patient with false-positive findings had a marginal negative CRM of only 1.4 mm. Receiver operating characteristic curve analysis of the fluorescence intensities of formalin-fixed tissue slices yielded an optimal mean fluorescence intensity cutoff value for tumor detection of 5,775 (sensitivity of 96.19% and specificity of 80.39%). Bevacizumab-800CW enabled a clear differentiation between tumor and normal tissue up to a microscopic level, with a tumor-to-background ratio of 4.7 ± 2.5 (mean ± SD). Conclusion: In this proof-of-concept study, we showed the potential of back-table FGI for evaluating the CRM status in LARC patients. Optimization of this technique with adaptation of standard operating procedures could change perioperative decision making with regard to extending resections or applying intraoperative radiation therapy in the case of positive CRM.

Background

Advances in information communications technology (ICT) provide opportunities for enhanced diabetes care. Knowledge of the more acceptable communication modalities in patients of different ages will help to inform the direction of future innovations.

ABSTRACT

Academics in non-tenure-track positions encounter a unique set of challenges on the road toward tenure. Institutionalized policies and lack of mentors are additional burdens for foreign scientists, resulting in representation differences. Becoming a scientist has been a personal and moving journey in which my multiple selves intersect and clash every now and again. My identity as a scientist is a life project and has intersected with my other identities: a young Latina immigrant in Western Europe. This crossroad has molded, and at times, challenged my participation in science.

The type VI secretion system (T6SS) is a weapon for delivering effectors into target cells that is widespread in Gram-negative bacteria. The T6SS is a highly versatile machine, as it can target both eukaryotic and prokaryotic cells, and it has been proposed that T6SSs are adapted to the specific needs of each bacterium. The expression of T6SS gene clusters and the activation of the secretion apparatus are therefore tightly controlled. In enteroaggregative Escherichia coli (EAEC), the sci1 T6SS gene cluster is subject to a complex regulation involving both the ferric uptake regulator (Fur) and DNA adenine methylase (Dam)-dependent DNA methylation. In this study, an additional, internal, promoter was identified within the sci1 gene cluster using +1 transcriptional mapping. Further analyses demonstrated that this internal promoter is controlled by a mechanism strictly identical to that of the main promoter. The Fur binding box overlaps the –10 transcriptional element and a Dam methylation site, GATC-32. Hence, the expression of the distal sci1 genes is repressed and the GATC-32 site is protected from methylation in iron-rich conditions. The Fur-dependent protection of GATC-32 was confirmed by an in vitro methylation assay. In addition, the methylation of GATC-32 negatively impacted Fur binding. The expression of the sci1 internal promoter is therefore controlled by iron availability through Fur regulation, whereas Dam-dependent methylation maintains a stable ON expression in iron-limited conditions.

IMPORTANCE Bacteria use weapons to deliver effectors into target cells. One of these weapons, the type VI secretion system (T6SS), assembles a contractile tail acting as a spring to propel a toxin-loaded needle. Its expression and activation therefore need to be tightly regulated. Here, we identified an internal promoter within the sci1 T6SS gene cluster in enteroaggregative E. coli. We show that this internal promoter is controlled by Fur and Dam-dependent methylation. We further demonstrate that Fur and Dam compete at the –10 transcriptional element to finely tune the expression of T6SS genes. We propose that this elegant regulatory mechanism allows the optimum production of the T6SS in conditions where enteroaggregative E. coli encounters competing species.

Shigella species, the causal agents of bacillary dysentery, use a type III secretion system (T3SS) to inject two waves of virulence proteins, known as effectors, into the colonic epithelium to subvert host cell machinery. Prior to host cell contact and secretion of the first wave of T3SS effectors, OspD1, an effector and antiactivator protein, prevents premature production of the second wave of effectors. Despite this important role, regulation of the ospD1 gene is not well understood. While ospD1 belongs to the large regulon of VirB, a transcriptional antisilencing protein that counters silencing mediated by the histone-like nucleoid structuring protein H-NS, it remains unclear if VirB directly or indirectly regulates ospD1. Additionally, it is not known if ospD1 is regulated by H-NS. Here, we identify the primary ospD1 transcription start site (+1) and show that the ospD1 promoter is remotely regulated by both VirB and H-NS. Our findings demonstrate that VirB regulation of ospD1 requires at least one of the two newly identified VirB regulatory sites, centered at –978 and –1270 relative to the ospD1 +1. Intriguingly, one of these sites lies on a 193-bp sequence found in three conserved locations on the large virulence plasmids of Shigella. The region required for H-NS-dependent silencing of ospD1 lies between –1120 and –820 relative to the ospD1 +1. Thus, our study provides further evidence that cis-acting regulatory sequences for transcriptional antisilencers and silencers, such as VirB and H-NS, can lie far upstream of the canonical bacterial promoter region (i.e., –250 to +1).

IMPORTANCE Transcriptional silencing and antisilencing mechanisms regulate virulence gene expression in many important bacterial pathogens. In Shigella species, plasmid-borne virulence genes, such as those encoding the type III secretion system (T3SS), are silenced by the histone-like nucleoid structuring protein H-NS and antisilenced by VirB. Previous work at the plasmid-borne icsP locus revealed that VirB binds to a remotely located cis-acting regulatory site to relieve transcriptional silencing mediated by H-NS. Here, we characterize a second example of remote VirB antisilencing at ospD1, which encodes a T3SS antiactivator and effector. Our study highlights that remote transcriptional silencing and antisilencing occur more frequently in Shigella than previously thought, and it raises the possibility that long-range transcriptional regulation in bacteria is commonplace.

ABSTRACTBackground:Female sex workers (FSWs) in Cameroon commonly have unmet need for contraception posing a high risk of unintended pregnancy. Unintended pregnancy leads to a range of outcomes, and due to legal restrictions, FSWs often seek unsafe abortions. Aside from the high burden of HIV, little is known about the broader sexual and reproductive health of FSWs in Cameroon.Methods:From December 2015 to October 2016, we recruited FSWs aged ≥18 years through respondent-driven sampling across 5 Cameroonian cities. Cross-sectional data were collected through a behavioral questionnaire. Modified-robust Poisson regression was used to approximate adjusted prevalence ratios (aPR) for TOP and current use of effective nonbarrier contraception.Results:Among 2,255 FSWs (median age 28 years), 57.6% reported history of unintended pregnancy and 40.0% reported prior TOP. In multivariable analysis, TOP history was associated with current nonbarrier contraceptive use (aPR=1.23, 95% confidence interval [CI]=1.07, 1.42); ever using emergency contraception (aPR=1.34, 95% CI=1.17, 1.55); >60 clients in the past month (aPR=1.29, 95% CI= 1.07, 1.54) compared to ≤30; inconsistent condom use with clients (aPR=1.17, 95% CI=1.00, 1.37); ever experiencing physical violence (aPR=1.24, 95% CI=1.09, 1.42); and older age. Most (76.5%) women used male condoms for contraception, but only 33.2% reported consistent condom use with all partners. Overall, 26.4% of women reported currently using a nonbarrier contraceptive method, and 6.2% reported using a long-acting method. Previous TOP (aPR=1.41, 95%CI=1.16, 1.72) and ever using emergency contraception (aPR=2.70, 95% CI=2.23, 3.26) were associated with higher nonbarrier contraceptive use. Recent receipt of HIV information (aPR=0.72, 95% CI=0.59, 0.89) and membership in an FSW community-based organization (aPR=0.73, 95% CI=0.57, 0.92) were associated with lower use nonbarrier contraceptive use.Conclusions:Experience of unintended pregnancies and TOP is common among FSWs in Cameroon. Given the low use of nonbarrier contraceptive methods and inconsistent condom use, FSWs are at risk of repeat unintended pregnancies. Improved integration of client-centered, voluntary family planning within community-led HIV services may better support the sexual and reproductive health and human rights of FSWs consistent with the United Nations Declaration of Human Rights.

Despite substantial progress in treatment of T-cell acute lymphoblastic leukemia (T-ALL), mortality remains relatively high, mainly due to primary or acquired resistance to chemotherapy. Further improvements in survival demand better understanding of T-ALL biology and development of new therapeutic strategies. The Notch pathway has been involved in the pathogenesis of this disease and various therapeutic strategies are currently under development, including selective targeting of NOTCH receptors by inhibitory antibodies. We previously demonstrated that the NOTCH1-specific neutralizing antibody OMP52M51 prolongs survival in TALL patient-derived xenografts bearing NOTCH1/FBW7 mutations. However, acquired resistance to OMP52M51 eventually developed and we used patient-derived xenografts models to investigate this phenomenon. Multi-level molecular characterization of T-ALL cells resistant to NOTCH1 blockade and serial transplantation experiments uncovered heterogeneous types of resistance, not previously reported with other Notch inhibitors. In one model, resistance appeared after 156 days of treatment, it was stable and associated with loss of Notch inhibition, reduced mutational load and acquired NOTCH1 mutations potentially affecting the stability of the heterodimerization domain. Conversely, in another model resistance developed after only 43 days of treatment despite persistent down-regulation of Notch signaling and it was accompanied by modulation of lipid metabolism and reduced surface expression of NOTCH1. Our findings shed light on heterogeneous mechanisms adopted by the tumor to evade NOTCH1 blockade and support clinical implementation of antibody-based target therapy for Notch-addicted tumors.

In iron-depleted women without anemia, oral iron supplements induce an increase in serum hepcidin (SHep) that persists for 24 hours, decreasing iron absorption from supplements given later on the same or next day. Consequently, iron absorption from supplements is highest if iron is given on alternate days. Whether this dosing schedule is also beneficial in women with iron-deficiency anemia (IDA) given high-dose iron supplements is uncertain. The primary objective of this study was to assess whether, in women with IDA, alternate-day administration of 100 and 200 mg iron increases iron absorption compared to consecutive-day iron administration. Secondary objectives were to correlate iron absorption with SHep and iron status parameters. We performed a cross-over iron absorption study in women with IDA (n=19; median hemoglobin 11.5 mg/dL; mean serum ferritin 10 mg/L) who received either 100 or 200 mg iron as ferrous sulfate given at 8 AM on days 2, 3 and 5 labeled with stable iron isotopes 57Fe, 58Fe and 54Fe; after a 16-day incorporation period, the other labeled dose was given at 8 AM on days 23, 24 and 26 (days 2, 3 and 5 of the second period). Iron absorption on days 2 and 3 (consecutive) and day 5 (alternate) was assessed by measuring erythrocyte isotope incorporation. For both doses, SHep was higher on day 3 than on day 2 (P<0.001) or day 5 (P<0.01) with no significant difference between days 2 and 5. Similarly, for both doses, fractional iron absorption (FIA) on days 2 and 5 was 40-50% higher than on day 3 (P<0.001), while absorption on day 2 did not differ significantly from day 5. There was no significant difference in the incidence of gastrointestinal side effects comparing the two iron doses (P=0.105). Alternate day dosing of oral iron supplements in anemic women may be preferable because it sharply increases FIA. If needed, to provide the same total amount of iron with alternate day dosing, twice the daily target dose should be given on alternate days, as total iron absorption from a single dose of 200 mg given on alternate days was approximately twice that from 100 mg given on consecutive days (P<0.001). In IDA, even if hepatic hepcidin expression is strongly suppressed by iron deficiency and erythropoietic drive, the intake of oral iron supplements leads to an acute hepcidin increase for 24 hours. The study was funded by ETH Zürich, Switzerland. This study has been registered at www.clinicaltrials.gov as #NCT03623997.

BackgroundAwareness of the importance of shared decision making (SDM) is widespread; however, little research has focused on discussions surrounding investigations, despite increasing laboratory testing in primary care.AimTo explore the discussion of blood tests in routine primary care consultations.Design and settingA secondary analysis of 50 video-recorded routine primary care consultations, linked surveys, and records data (all from the One in a Million [OiaM] archive). The consultations were taken by 22 GPs across 12 practices.MethodA coding scheme was developed, using qualitative content analysis, to explore discussion of blood tests in transcripts of recorded consultations. Codes focused on instigating testing, the extent of SDM, and how results were explained. Survey data were used to compare patients’ pre-visit expectations with consultation content. Medical records were reviewed to compare tests discussed with those ordered.ResultsIn 36 out of 50 consultations that discussed ordering blood tests, 11 patients (31%) hinted that they wanted a blood test; however, none asked explicitly. Only four patients (11%) were offered alternative options. In 29 cases (81%) the GP gave some explanation of the indication, but only in six cases (17%) were the limitations of testing explained. Only 10 out of 31 patients (32%) were informed about all blood tests ordered. Of the 23 out of 50 consultations in which results were conveyed, the GP gave no explanation of the results in six cases (26%). Thirteen patients (57%) were only informed of an assessment of the results (for example, ‘normal’), rather than the actual results.ConclusionA lack of information dissemination and SDM exists around ordering tests and conveying results. Promoting SDM could reduce unnecessary testing and improve patient-centred care.

Background:

Previous studies examining potential sex and gender bias in the Canadian Resident Matching Service (CaRMS) match have had conflicting results. We examined the results of the CaRMS match over the period 2013–2019 to determine the potential association between applicants’ gender and the outcome of matching to their first-choice discipline.

Background:

It is unclear how patient-reported access to primary care differs by physician payment model and participation in team-based care. We examined the association between timely and after-hours access to primary care and physician payment model and participation in team-based care, and sought to assess how access varied by patient characteristics.

Background:

Drugs are the fastest growing cost in the Canadian health care system, owing to the increasing number of high-cost drugs. The objective of this study was to examine the characteristics of high–drug-cost beneficiaries of public drug plans across Canada relative to other beneficiaries.

Combined pre-and post-capillary hypertension (CpcPH) is a relatively common complication of heart failure (HF) associated with a poor prognosis. Currently, there is no specific therapy approved for this entity. Recently, treatment with beta-3 adrenergic receptor (β3AR) agonists was able to improve pulmonary hemodynamics and right ventricular (RV) performance in a translational, large animal model of chronic PH. The authors present the design of a phase II randomized clinical trial that tests the benefits of mirabegron (a clinically available β3AR agonist) in patients with CpcPH due to HF. The effect of β3AR treatment will be evaluated on pulmonary hemodynamics, as well as clinical, biochemical, and advanced cardiac imaging parameters. (Beta3 Agonist Treatment in Chronic Pulmonary Hypertension Secondary to Heart Failure [SPHERE-HF]; NCT02775539)