Pseudomonas aeruginosa is a major cause of severe infections that lead to bacteremia and high patient mortality. P. aeruginosa has evolved numerous evasion and subversion mechanisms that work in ...concert to overcome immune recognition and effector functions in hospitalized and immunosuppressed individuals. Here, we have used multilaser spinning-disk intravital microscopy to monitor the blood-borne stage in a murine bacteremic model of P. aeruginosa infection. P. aeruginosa adhered avidly to lung vasculature, where patrolling neutrophils and other immune cells were virtually blind to the pathogen's presence. This cloaking phenomenon was attributed to expression of Psl exopolysaccharide. Although an anti-Psl mAb activated complement and enhanced neutrophil recognition of P. aeruginosa, neutrophil-mediated clearance of the pathogen was suboptimal owing to a second subversion mechanism, namely the type 3 secretion (T3S) injectisome. Indeed, T3S prevented phagosome acidification and resisted killing inside these compartments. Antibody-mediated inhibition of the T3S protein PcrV did not enhance bacterial phagocytosis but did enhance killing of the few bacteria ingested by neutrophils. A bispecific mAb targeting both Psl and PcrV enhanced neutrophil uptake of P. aeruginosa and also greatly increased inhibition of T3S function, allowing for phagosome acidification and bacterial killing. These data highlight the need to block multiple evasion and subversion mechanisms in tandem to kill P. aeruginosa.
How can instructors best foster connections among students when learning is fully remote? This article describes a pedagogical experiment conducted in two large introductory political science courses ...at a large public university in the 2020–2021 academic year. We randomly assigned groups of students to different sets of instructions on how to study together remotely for an exam. Our strongest finding is that almost any effort by an instructor prompting students to work together helps students to feel more connected to one another; however, students often need to see and hear one another to feel connected. We find this to be tremendously encouraging—relatively easy interventions can result in significant improvements in learning.
Molecular tools for modulating transgene expression in Aedes aegypti are few. Here we demonstrate that adjustments to the AePUb promoter length can alter expression levels of two reporter proteins in ...Ae. aegypti cell culture and in mosquitoes. This provides a simple means for increasing or decreasing expression of a gene of interest and easy translation from cells to whole insects.
'Make me comfortable' were the last words of Sergeant First Class Randy Johnson of the United States 2nd Stryker Cavalry Regiment. The investigation into his murder would take seven years, span three ...countries, and involve forensic and technical exploitation analysis in the United States and the United Kingdom. The purpose of this case study is to discuss the unique aspects of battlefield forensic science and key factors that can lead to the prosecution of foreign terrorist fighters to meet obligations under United Nations Security Council Resolution 2396 (2017) and 2322 (2016) for member states to investigate foreign terrorist fighters.
Reproduction can lead to a trade-off with growth, particularly when individuals reproduce before completing body growth. Kangaroos have indeterminate growth and may always face this trade-off. We ...combined an experimental manipulation of reproductive effort and multi-year monitoring of a large sample size of marked individuals in two populations of eastern grey kangaroos to test the predictions (1) that reproduction decreases skeletal growth and mass gain and (2) that mass loss leads to reproductive failure. We also tested if sex-allocation strategies influenced these trade-offs. Experimental reproductive suppression revealed negative effects of reproduction on mass gain and leg growth from 1 year to the next. Unmanipulated females, however, showed a positive correlation between number of days lactating and leg growth over periods of 2 years and longer, suggesting that over the long term, reproductive costs were masked by individual heterogeneity in resource acquisition. Mass gain was necessary for reproductive success the subsequent year. Although mothers of daughters generally lost more mass than females nursing sons, mothers in poor condition experienced greater mass gain and arm growth if they had daughters than if they had sons. The strong links between individual mass changes and reproduction suggest that reproductive tactics are strongly resource-dependent.
The phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin is a key pathway of survival and therapeutic resistance in breast cancer. We evaluated the pan-Akt inhibitor MK-2206 in combination ...with standard therapy in patients with high-risk early-stage breast cancer.
I-SPY 2 is a multicenter, phase II, open-label, adaptively randomized neoadjuvant platform trial that screens experimental therapies and efficiently identifies potential predictive biomarker signatures. Patients are categorized by human epidermal growth factor receptor 2 (HER2), hormone receptor (HR), and MammaPrint statuses in a 2 × 2 × 2 layout. Patients within each of these 8 biomarker subtypes are adaptively randomly assigned to one of several experimental therapies, including MK-2206, or control. Therapies are evaluated for 10 biomarker signatures, each of which is a combination of these subtypes. The primary end point is pathologic complete response (pCR). A therapy graduates with one or more of these signatures if and when it has an 85% Bayesian predictive probability of success in a hypothetical phase III trial, adjusting for biomarker covariates. Patients in the current report received standard taxane- and anthracycline-based neoadjuvant therapy without (control) or with oral MK-2206 135 mg/week.
MK-2206 graduated with 94 patients and 57 concurrently randomly assigned controls in 3 graduation signatures: HR-negative/HER2-positive, HR-negative, and HER2-positive. Respective Bayesian mean covariate-adjusted pCR rates and percentage probability that MK-2206 is superior to control were 0.48:0.29 (97%), 0.62:0.36 (99%), and 0.46:0.26 (94%). In exploratory analyses, MK-2206 evinced a numerical improvement in event-free survival in its graduating signatures. The most significant grade 3-4 toxicity was rash (14% maculopapular, 8.6% acneiform).
The Akt inhibitor MK-2206 combined with standard neoadjuvant therapy resulted in higher estimated pCR rates in HR-negative and HER2-positive breast cancer. Although MK-2206 is not being further developed at this time, this class of agents remains of clinical interest.
Multiple drug discovery initiatives for tuberculosis are currently ongoing to identify and develop new potent drugs with novel targets in order to shorten treatment duration. One of the drug classes ...with a new mode of action is DprE1 inhibitors targeting an essential process in cell wall synthesis of Mycobacterium tuberculosis. In this investigation, three DprE1 inhibitors currently in clinical trials, TBA-7371, PBTZ169, and OPC-167832, were evaluated side-by-side as single agents in the C3HeB/FeJ mouse model presenting with caseous necrotic pulmonary lesions upon tuberculosis infection. The goal was to confirm the efficacy of the DprE1 inhibitors in a mouse tuberculosis model with advanced pulmonary pathology and perform comprehensive analysis of plasma, lung, and lesion-centric drug levels to establish pharmacokinetic-pharmacodynamic (PK-PD) parameters predicting efficacy at the site of infection. Results showed significant efficacy for all three DprE1 inhibitors in the C3HeB/FeJ mouse model after 2 months of treatment. Superior efficacy was observed for OPC-167832 even at low-dose levels, which can be attributed to its low MIC, favorable distribution, and sustained retention above the MIC throughout the dosing interval in caseous necrotic lesions, where the majority of bacteria reside in C3HeB/FeJ mice. These results support further progression of the three drug candidates through clinical development for tuberculosis treatment.
There is urgent need for new drug regimens that more rapidly cure tuberculosis (TB). Existing TB drugs and regimens vary in treatment-shortening activity, but the molecular basis of these differences ...is unclear, and no existing assay directly quantifies the ability of a drug or regimen to shorten treatment. Here, we show that drugs historically classified as sterilizing and non-sterilizing have distinct impacts on a fundamental aspect of Mycobacterium tuberculosis physiology: ribosomal RNA (rRNA) synthesis. In culture, in mice, and in human studies, measurement of precursor rRNA reveals that sterilizing drugs and highly effective drug regimens profoundly suppress M. tuberculosis rRNA synthesis, whereas non-sterilizing drugs and weaker regimens do not. The rRNA synthesis ratio provides a readout of drug effect that is orthogonal to traditional measures of bacterial burden. We propose that this metric of drug activity may accelerate the development of shorter TB regimens.
1. When resources are scarce, female mammals should face a trade-off between lactation and other life-history traits such as growth, survival and subsequent reproduction. Kangaroos are ideal to test ...predictions about reproductive costs because they may simultaneously lactate and carry a young, and have indeterminate growth and a long breeding season. 2. An earlier study in three of our five study populations prevented female eastern grey kangaroos (Macropus giganteus) from reproducing during one reproductive season by either inserting contraceptive implants or removing very small pouch young. We explored how individual and environmental variables affect the costs of reproduction over time, combining this experimental reduction of reproductive effort with multi-year monitoring of 270 marked females. Experimental manipulation should control for individual heterogeneity, revealing the costs of reproduction and their likely sources. We also examined the fitness consequences of reproductive effort and offspring sex among unmanipulated individuals to test whether sex allocation strategies affected trade-offs. 3. Costs of reproduction included longer inter-birth intervals and lower probability of producing a young that survived to 7 months in the subsequent reproductive event. Weaning success, however, did not differ significantly between manipulated and control females. By reducing reproductive effort, manipulation appeared to increase individual condition and subsequent reproductive success. 4. Effects of offspring sex upon subsequent reproductive success varied according to year and study population. Mothers of sons were generally more likely to have a young that survived to 7 months, compared to mothers of daughters. 5. The fitness costs of reproduction arise from constraints in both acquisition and allocation of resources. To meet these costs, females delay subsequent parturition and may manipulate offspring sex. Reproductive tactics thus vary according to the amount of resource available to each individual, promoting a wide range in reproductive performance within and among individuals and populations.
In mammals, lactation is the most energetically demanding component of female reproduction. Theory predicts an increase in food intake by lactating females, but very few studies have used ...contraceptives to experimentally test the influence of reproduction on foraging behaviour of wild mammals. From 2009 to 2011, we observed 182 individually marked female eastern grey kangaroos, Macropus giganteus, in two populations, including 29 that received an experimental contraceptive treatment. We sought to determine whether lactating females increase their foraging rate compared to contracepted and naturally nonlactating females. The proportion of time spent foraging during 10min focal samples did not vary according to reproductive status in one population. In the other, lactating females spent 4% less time feeding than nonlactating females. Day and midday activity and bite and chewing rates were higher in lactating than in nonlactating females. Bite rate increased with the size of the pouch young and was higher for mothers of sons than for mothers of daughters. Bite rate was also affected by reproductive effort in the previous year, being higher for females that had weaned a young. Foraging behaviour was independent of body mass and group size, but bite rate appeared to decrease with female age. In one population, we found strong effects of date and year on foraging behaviour. Our study is a rare experimental manipulation of reproduction in free-ranging large mammals. We found that foraging behaviours were affected by both previous and current reproductive effort and varied with individual characteristics and environmental conditions.
•We examined whether female eastern grey kangaroos increase food intake during lactation.•We observed foraging behaviour of lactating, nonlactating and experimentally contracepted free-ranging females.•Females increased food intake by 53% during peak lactation.•Mothers of sons showed the highest rate of food intake.•Foraging behaviour in this species is affected by both current and previous reproductive effort.
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