Adaptations of Pseudomonas aeruginosa to the Cystic Fibrosis Lung Environment Can Include Deregulation of zwf, Encoding Glucose-6-Phosphate Dehydrogenase

Cystic fibrosis (CF) patients are highly susceptible to chronic pulmonary disease caused by mucoid Pseudomonas aeruginosa strains that overproduce the exopolysaccharide alginate. We showed here that a mutation in zwf, encoding glucose-6-phosphate dehydrogenase (G6PDH), leads to a 90% reduction in alginate production in the mucoid, CF isolate, P. aeruginosa FRD1. The main regulator of alginate, sigma-22 encoded by algT (algU), plays a small but demonstrable role in the induction of zwf expression in P. aeruginosa. However, G6PDH activity and zwf expression were higher in FRD1 strains than in PAO1 strains. In PAO1, zwf expression and G6PDH activity are known to be subject to catabolite repression by succinate. In contrast, FRD1 zwf expression and G6PDH activity were shown to be refractory to such catabolite repression. This was apparently not due to a defect in the catabolite repression control (Crc) protein. Such relaxed control of zwf was found to be common among several examined CF isolates but was not seen in other strains of clinical and environmental origin. Two sets of clonal isolates from individual CF patient indicated that the resident P. aeruginosa strain underwent an adaptive change that deregulated zwf expression. We hypothesized that high-level, unregulated G6PDH activity provided a survival advantage to P. aeruginosa within the lung environment. Interestingly, zwf expression in P. aeruginosa was shown to be required for its resistance to human sputum. This study illustrates that adaptation to the CF pulmonary environment by P. aeruginosa can include altered regulation of basic metabolic activities, including carbon catabolism. Originally published Journal of Bacteriology, Vol. 187, No. 22, Nov 200

Identification and specificity of broadly neutralizing antibodies against HIV

Summary Beginning in 2009, studies of the humoral responses of HIV‐positive individuals have led to the identification of scores, if not hundreds, of antibodies that are both broadly reactive and potently neutralizing. This development has provided renewed impetus toward an HIV vaccine and led directly to the development of novel immunogens. Advances in identification of donors with the most potent and broad anti‐HIV serum neutralizing responses were crucial in this effort. Equally, development of methods for the rapid generation of human antibodies from these donors was pivotal. Primarily these methods comprise single B‐cell culture coupled to high‐throughput neutralization screening and flow cytometry‐based sorting of single B cells using HIV envelope protein baits. In this review, the advantages and disadvantages of these methodologies are discussed in the context of the specificities targeted by individual antibodies and the need for further improvements to evaluate HIV vaccine candidates

Implicit and Explicit Alcohol-Related Motivations among College Binge Drinkers

Rationale: Positive alcohol outcome expectancies and behavioral economic indices of alcohol consumption are related to binge drinking among college students and may reflect explicit and implicit motivations that are differentially associated with this behavior. Objectives: The present study hypothesized that implicit (alcohol purchase task) and explicit (positive expectancy for alcohol’s effects) motivations for drinking would not be correlated. It was also hypothesized that greater implicit and explicit motivations would predict alcohol-related risk. Methods: Participants were 297 college student binge drinkers (54% female; 88% European-American; Alcohol Use Disorders Identification Test: M = 9.53, SD = 5.04). Three indices from the alcohol purchase task (APT) were modeled as a latent implicit alcohol-related motivations variable. Explicit alcohol-related motivations were measured using a global positive expectancy subscale from the Comprehensive Effects of Alcohol Questionnaire. Alcohol Use Disorders Identification Test total, Rutgers Alcohol Problem Index total, and age of drinking onset were modeled as a latent alcohol-related risk variable. Structural equation modeling was used to examine associations among implicit motivations, explicit motivations, and alcohol-related risk. Results: Implicit and explicit motivations were not correlated. Partially consistent with the second hypothesis, greater implicit motivations were associated with greater alcohol-related risk. Relations between explicit motivations and alcohol-related risk were marginally significant. Conclusions: Implicit and explicit drinking motivations are differentially associated with problem drinking behaviors. Future research should examine the underlying neurobiological mechanisms associated with these factors

A GABAergic projection from the centromedial nuclei of the amygdala to ventromedial prefrontal cortex modulates reward behavior

The neural circuitry underlying mammalian reward behaviors involves several distinct nuclei throughout the brain. It is widely accepted that the midbrain dopamine (DA) neurons are critical for the reward-related behaviors. Recent studies have shown that the centromedial nucleus of the amygdala (CeMA) has a distinct role in regulating reward-related behaviors. However, the CeMA and ventromedial PFC (vmPFC) interaction in reward regulation remains poorly understood. Here, we identify and dissect a GABAergic projection that originates in the CeMA and terminates in the vmPFC (VGat-Cre(CeMA-vmPFC)) using viral-vector-mediated, cell-type-specific optogenetic techniques in mice. Pathway-specific optogenetic activation of the VGat-Cre(CeMA-vmPFC) circuit in awake, behaving animals produced a positive, reward-like phenotype in real-time place preference and increased locomotor activity in open-field testing. In sucrose operant conditioning, the photoactivation of these terminals increased nose-poking effort with no effect on licking behavior and robustly facilitated the extinction of operant behavior. However, photoactivation of these terminals did not induce self-stimulation in the absence of an external reward. The results described here suggest that the VGat-Cre(CeMA-vmPFC) projection acts to modulate existing reward-related behaviors. SIGNIFICANCE STATEMENT Many studies have shown that the interactions between the centromedial nucleus of the amygdala (CeMA) and ventromedial PFC (vmPFC) have critical roles for emotional regulation. However, most studies have associated this circuit with fear and anxiety behaviors and emphasized top-down processing from vmPFC to CeMA. Here, we provide new evidence for bottom-up CeMA to vmPFC influence on reward-related behaviors. Although previous work implicated the CeMA in incentive salience, our results isolate the investigation to a specific CeMA GABAergic projection to the vmPFC. This long-range GABAergic interaction between amygdala and frontal cortex adds a new dimension to the complex regulation of reward-related behaviors

Perspectives on Extended-Release Naltrexone Induction among Patients Living with HIV and Opioid Use Disorder: A Qualitative Analysis

BACKGROUND: The CHOICES study randomized participants with HIV and opioid use disorder (OUD) to HIV clinic-based extended-release naltrexone (XR-NTX), which requires complete cessation of opioid use, versus treatment-as-usual (i.e., buprenorphine, methadone). Study participants randomized to XR-NTX were interviewed to assess their experiences with successful and unsuccessful XR-NTX induction. METHODS: Semi-structured qualitative interviews were completed with a convenience sample of study participants with HIV and OUD (n = 37) randomized to XR-NTX in five HIV clinics between 2018 and 2019. All participants approached agreed to be interviewed. Interviews were digitally recorded, professionally transcribed, and analyzed using thematic analysis. RESULTS: Participants included women (43%), African Americans (62%) and Hispanics (16%), between 27 to 69 years of age. Individuals who completed XR-NTX induction (n = 20) reported experiencing (1) readiness for change, (2) a supportive environment during withdrawal including comfort medications, and (3) caring interactions with staff. Four contrasting themes emerged among participants (n = 17) who did not complete induction: (1) concern and anxiety about withdrawal including past negative experiences, (2) ambivalence about or reluctance to stop opioids, (3) concerns about XR-NTX effects, and (4) preferences for other medications. CONCLUSIONS: The results highlight opportunities to improve initiation of XR-NTX in high-need groups. Addressing expectations regarding induction may enhance XR-NTX initiation rates. Trial Registration ClinicalTrials.gov: NCT03275350. Registered September 7, 2017. https://clinicaltrials.gov/ct2/show/NCT03275350?term=extended+release+naltrexone&cond=Opioid+Use

Nutrient content and stoichiometry of pelagic Sargassum reflects increasing nitrogen availability in the Atlantic Basin

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lapointe, B. E., Brewton, R. A., Herren, L. W., Wang, M., Hu, C., McGillicuddy, D. J., Lindell, S., Hernandez, F. J., & Morton, P. L. Nutrient content and stoichiometry of pelagic Sargassum reflects increasing nitrogen availability in the Atlantic Basin. Nature Communications, 12(1), (2021): 3060, https://doi.org/10.1038/s41467-021-23135-7.The pelagic brown macroalgae Sargassum spp. have grown for centuries in oligotrophic waters of the North Atlantic Ocean supported by natural nutrient sources, such as excretions from associated fishes and invertebrates, upwelling, and N2 fixation. Using a unique historical baseline, we show that since the 1980s the tissue %N of Sargassum spp. has increased by 35%, while %P has decreased by 44%, resulting in a 111% increase in the N:P ratio (13:1 to 28:1) and increased P limitation. The highest %N and δ15N values occurred in coastal waters influenced by N-rich terrestrial runoff, while lower C:N and C:P ratios occurred in winter and spring during peak river discharges. These findings suggest that increased N availability is supporting blooms of Sargassum and turning a critical nursery habitat into harmful algal blooms with catastrophic impacts on coastal ecosystems, economies, and human health.This work was funded by the US NASA Ocean Biology and Biogeochemistry Program (80NSSC20M0264, NNX16AR74G) and Ecological Forecast Program (NNX17AF57G), NOAA RESTORE Science Program (NA17NOS4510099), National Science Foundation (NSF-OCE 85–15492 and OCE 88–12055), “Save Our Seas” Specialty License Plate funds, granted through the Harbor Branch Oceanographic Institute Foundation, Ft. Pierce, FL, and a Red Wright Fellowship from the Bermuda Biological Station. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida. D.J.M. gratefully acknowledges the Holger W. Jannasch and Columbus O’Donnell Iselin Shared Chairs for Excellence in Oceanography, as well as support from the Mill Reef Fund

Physiological consequences of rising water salinity for a declining freshwater turtle.

Sea-level rise, drought and water diversion can all lead to rapid salinization of freshwater habitats, especially in coastal areas. Increased water salinities can in turn alter the geographic distribution and ecology of freshwater species including turtles. The physiological consequences of salinization for freshwater turtles, however, are poorly known. Here, we compared the osmoregulatory response of two geographically separate populations of the freshwater Western Pond Turtle (Actinemys marmorata)-a species declining across its range in western North America-to three constant salinities: 0.4 ppt, 10 ppt and 15 ppt over 2 weeks. We found that turtles from a coastal estuarine marsh population regulated their plasma osmolality at lower levels than their conspecifics from an inland freshwater creek population 45 km away. Plasma osmolalities were consistently lower in estuarine marsh turtles than the freshwater creek turtles over the entire 2-week exposure to 10 ppt and 15 ppt water. Furthermore, estuarine marsh turtles maintained plasma osmolalities within 1 SD of their mean field osmolalities over the 2-week exposure, whereas freshwater creek turtles exceeded their field values within the first few days after exposure to elevated salinities. However, individuals from both populations exhibited body mass loss in 15 ppt water, with significantly greater loss in estuarine turtles. We speculate that the greater ability to osmoregulate by the estuarine marsh turtles may be explained by their reduced feeding and drinking in elevated salinities that was not exhibited by the freshwater creek population. However, due to mass loss in both populations, physiological and behavioural responses exhibited by estuarine marsh turtles may only be effective adaptations for short-term exposures to elevated salinities, such as those from tides and when traversing saline habitats, and are unlikely to be effective for long-term exposure to elevated salinity as is expected under sea-level rise

Distinct Immune Profiles of Exhausted Effector and Memory CD8+ T Cells in Individuals With Filarial Lymphedema

CD8+ T cells are crucial for the clearance of viral infections, and current research begins to highlight their importance in parasitic diseases too. In-depth research about characteristics of CD8+ T-cell subsets and exhaustion remains uncertain, especially during filariasis, a chronic helminth infection. Lymphatic filariasis, elicited by Wuchereria bancrofti, remains a serious health problem in endemic areas in Ghana, especially in those suffering from morbidity due to lymphedema (LE). In this observational study, the characteristics and profiles of CD8+ T cells were compared between asymptomatic Wuchereria bancrofti-infected individuals, uninfected endemic normals, and those with LE (grades 2–6). Focusing on exhausted memory (CD8+exmem: CD8+ T-betdimEomeshi) and effector (CD8+exeff: CD8+T-bethiEomesdim) CD8+ T-cell subsets, advanced flow cytometry revealed that LE individuals presented reduced frequencies of IFN-γ+CD8+exmem T cells expressing Tim-3 or LAG-3 which negatively correlated to the presence of LE. Moreover, the LE cohort further showed significantly higher frequencies of IL-10+CD8+exeff T cells expressing either Tim-3, LAG-3, CD39, KLRG-1, or PD-1, all associated markers of exhaustion, and that these frequencies positively correlated with the presence of LE. In summary, this study shows that distinct exhausted CD8+ T-cell subsets are prominent in individuals suffering from LE, suggesting that enhanced inflammation and constant immune activation might drive exhaustion of CD8+ T cells. Since T-cell exhaustion is known to be associated with insufficient control of persisting antigen, the data presented here reveals that these CD8+ T-cell exhaustion patterns in filarial LE should be taken into consideration for prevention and control management of LE

Coibacins A D, Antileishmanial Marine Cyanobacterial Polyketides with Intriguing Biosynthetic Origins

Four unsaturated polyketide lactone derivatives, coibacins A-D, were isolated from a Panamanian marine cyanobacterium, cf. Oscillatoria sp. The two different types of termini observed in these co-occurring metabolites, either a methyl cyclopropyl ring as seen in curacin A or a methyl vinyl chloride similar to that observed in the jamaicamides, suggest an intriguing flexibility in the “beta branch” forming biosynthetic process. The coibacins possess selective antileishmanial activity as well as potent anti-inflammatory activity.Four unsaturated polyketide lactone derivatives, coibacins A-D, were isolated from a Panamanian marine cyanobacterium, cf. Oscillatoria sp. The two different types of termini observed in these co-occurring metabolites, either a methyl cyclopropyl ring as seen in curacin A or a methyl vinyl chloride similar to that observed in the jamaicamides, suggest an intriguing flexibility in the “beta branch” forming biosynthetic process. The coibacins possess selective antileishmanial activity as well as potent anti-inflammatory activity