Macrophages inhibit extracellular hyphal growth of A. fumigatus through Rac2 GTPase signaling.

Macrophages act as a first line of defense against pathogens. Against Aspergillus fumigatus, a fungus with pathogenic potential in immunocompromised patients, macrophages can phagocytose fungal spores and inhibit spore germination to prevent the development of tissue-invasive hyphae. However, the cellular pathways that macrophages use to accomplish these tasks and any roles macrophages have later in infection against invasive forms of fungi are still not fully known. Rac-family Rho GTPases are signaling hubs for multiple cellular functions in leukocytes, including cell migration, phagocytosis, reactive oxygen species (ROS) generation, and transcriptional activation. We therefore aimed to further characterize the function of macrophages against A. fumigatus in an in vivo vertebrate infection model by live imaging of the macrophage behavior in A. fumigatus-infected rac2 mutant zebrafish larvae. While Rac2-deficient zebrafish larvae are susceptible to A. fumigatus infection, Rac2 deficiency does not impair macrophage migration to the infection site, interaction with and phagocytosis of spores, spore trafficking to acidified compartments, or spore killing. However, we reveal a role for Rac2 in macrophage-mediated inhibition of spore germination and control of invasive hyphae. Re-expression of Rac2 under a macrophage-specific promoter rescues the survival of A. fumigatus-infected rac2 mutant larvae through increased control of germination and hyphal growth. Altogether, we describe a new role for macrophages against extracellular hyphal growth of A. fumigatus and report that the function of the Rac2 Rho GTPase in macrophages is required for this function.

External validation of prognostic rules for early post-pulmonary embolism mortality: assessment of a claims-based and three clinical-based approaches.

BACKGROUND: Studies show the In-hospital Mortality for Pulmonary embolism using Claims daTa (IMPACT) rule can accurately identify pulmonary embolism (PE) patients at low-risk of early mortality in a retrospective setting using only claims for the index admission. We sought to externally validate IMPACT, Pulmonary Embolism Severity Index (PESI), simplified PESI (sPESI) and Hestia for predicting early mortality. METHODS: We identified consecutive adults admitted for objectively-confirmed PE between 10/21/2010 and 5/12/2015. Patients undergoing thrombolysis/embolectomy within 48 h were excluded. All-cause in-hospital and 30 day mortality (using available Social Security Death Index data through January 2014) were assessed and prognostic accuracies of IMPACT, PESI, sPESI and Hestia were determined. RESULTS: Twenty-one (2.6 %) of the 807 PE patients died before discharge. All rules classified 26.1-38.3 % of patients as low-risk for early mortality. Fatality among low-risk patients was 0 % (sPESI and Hestia), 0.4 % (IMPACT) and 0.6 % (PESI). IMPACT's sensitivity was 95.2 % (95 % confidence interval [CI] = 74.1-99.8 %), and the sensitivities of clinical rules ranged from 91 (PESI)-100 % (sPESI and Hestia). Specificities of all rules ranged between 26.8 and 39.1 %. Of 573 consecutive patients in the 30 day mortality analysis, 33 (5.8 %) died. All rules classified 27.9-38.0 % of patients as low-risk, and fatality occurred in 0 (Hestia)-1.4 % (PESI) of low-risk patients. IMPACT's sensitivity was 97.0 % (95%CI = 82.5-99.8 %), while sensitivities for clinical rules ranged from 91 (PESI)-100 % (Hestia). Specificities of rules ranged between 29.6 and 39.8 %. CONCLUSION: In this analysis, IMPACT identified low-risk PE patients with similar accuracy as clinical rules. While not intended for prospective clinical decision-making, IMPACT appears useful for identification of low-risk PE patient in retrospective claims-based studies.

"My Autism is Linked with Everything": at the Crossroads of Autism and Diabetes.

Autistic adults experience stark health disparities and difficulties accessing health care. Their realities of managing complex health conditions are unknown. Our research explored the experience of Autistic adults self-managing diabetes. Interviews with Autistic adults with diabetes and their support people were thematically analysed to identify three key themes. The Autistic experience influenced diabetes self-management, including autism-unique challenges and strengths. Participants prioritised avoiding Autistic burnout over diabetes self-management; mitigating the psychosocial pressures of neurotypical systems took precedence. Health professionals often separated autism and diabetes subsequently overlooking key factors impacting diabetes self-management. To better meet the needs of Autistic adults, diabetes care and health management more broadly should be considered within the context of autism, including supports for self-management during Autistic burnout.

Expression profiles of Na+,K+-ATPase during acute and chronic hypo-osmotic stress in the blue crab Callinectes sapidus.

During acclimation to dilute seawater, the specific activity of Na+,K+-ATPase increases substantially in the posterior gills of the blue crab Callinectes sapidus. To determine whether this increase occurs through regulation of pre-existing enzyme or synthesis of new enzyme, mRNA and protein levels were measured over short (<24 h) and long (18 days) time courses. Na+,K+-ATPase expression, both mRNA and protein, did not change during the initial 24-h exposure to dilute seawater (10 ppt salinity). Thus, osmoregulation in C. sapidus during acute exposure to low salinity likely involves either modulation of existing enzyme or mechanisms other than an increase in the amount of Na+,K+-ATPase enzyme. However, crabs exposed to dilute seawater over 18 days showed a 300% increase in Na+,K+-ATPase specific activity as well as a 200% increase in Na+,K+-ATPase protein levels. Thus, it appears that the increase in Na+,K+-ATPase activity during chronic exposure results from the synthesis of new enzyme. The relative amounts of mRNA for the alpha-subunit increased substantially (by 150%) during the acclimation process, but once the crabs had fully acclimated to low salinity, the mRNA levels had decreased and were not different from levels in crabs fully acclimated to high salinity. Thus, there is transient induction of the Na+,K+-ATPase mRNA levels during acclimation to dilute seawater.

Biogeographic comparisons of marine algal polyphenolics: evidence against a latitudinal trend.

Marine allelochemicals generally are present in greater quantity and diversity in tropical than in temperate regions. Marine algal polyphenolics have been reported as an apparent exception to this biogeographic trend, with literature values for phenolic concentrations significantly higher in temperate than in tropical brown algae. In contrast, our results, the first reported for Caribbean brown algae (orders Dictyotales and Fucales), show that many species have high phenolic levels. In addition, both our study and previous studies with north temperate and tropical species demonstrate that there is marked variation in algal phenolic levels within species from different locations. We conclude that high phenolic concentrations occur in species from both temperate and tropical regions, indicating that latitude alone is not a reasonable predictor of plant phenolic concentrations.

Three members of the LC8/DYNLL family are required for outer arm dynein motor function.

The highly conserved LC8/DYNLL family proteins were originally identified in axonemal dyneins and subsequently found to function in multiple enzyme systems. Genomic analysis uncovered a third member (LC10) of this protein class in Chlamydomonas. The LC10 protein is extracted from flagellar axonemes with 0.6 M NaCl and cofractionates with the outer dynein arm in sucrose density gradients. Furthermore, LC10 is specifically missing only from axonemes of those strains that fail to assemble outer dynein arms. Previously, the oda12-1 insertional allele was shown to lack the Tctex2-related dynein light chain LC2. The LC10 gene is located approximately 2 kb from that of LC2 and is also completely missing from this mutant but not from oda12-2, which lacks only the 3' end of the LC2 gene. Although oda12-1 cells assemble outer arms that lack only LC2 and LC10, this strain exhibits a flagellar beat frequency that is consistently less than that observed for strains that fail to assemble the entire outer arm and docking complex (e.g., oda1). These results support a key regulatory role for the intermediate chain/light chain complex that is an integral and highly conserved feature of all oligomeric dynein motors.

The effects of hypoxia and pH on phenoloxidase activity in the Atlantic blue crab, Callinectes sapidus.

In its natural coastal and estuarine environments, the blue crab, Callinectes sapidus, often encounters hypoxia, accompanied by hypercapnia (increased CO2) and an associated decrease in water pH. Previous studies have shown that exposure to hypercapnic hypoxia (HH) impairs the crab's ability to remove culturable bacteria from its hemolymph. In the present study we demonstrate that the activity of phenoloxidase (PO), an enzyme critical to antibacterial immune defense in crustaceans, is decreased at the low levels of hemolymph O2 and pH that occur in the tissues of blue crabs exposed to HH. Hemocyte PO activity was measured at tissue O2 levels that occur in normoxic (5% and 15% O2, approximate venous and arterial hemolymph, respectively) and hypoxic (1% O2) crabs and compared to PO activity in air-saturated conditions (21% O2). PO activity decreased by 33%, 49% and 70% of activity in air at 15%, 5% and 1% O2, respectively. When O2 was held at 21% and pH lowered within physiological limits, PO activity decreased with pH, showing a 16% reduction at pH 7.0 as compared with a normoxic pH of 7.8. These results suggest that decreased PO activity at low tissue O2 and pH compromises the ability of crustaceans in HH to defend themselves against microbial pathogens.

The effect of seawater composition and osmolality on hemolymph levels of methyl farnesoate in the green crab Carcinus maenas.

Green crabs, Carcinus maenas, exposed to dilute seawater (e.g., 5 ppt salinity, approximately 150 mOsm/kg) have hemolymph levels of methyl farnesoate (MF) that are up to 10-fold higher than animals in isosmotic seawater (27 ppt, approximately 800 mOsm/kg). In this paper, we examine aspects of osmotic and ionic stress to identify factors involved in elevating MF levels. MF levels did not rise after exposure to concentrated seawater, so only hypoosmotic stress elevates MF. MF levels rose in animals exposed to dilute seawater containing mannitol to make it isosmotic, indicating that the hypoosmotic rise in MF is due to decreased ion concentrations. Individual ions were investigated by exposing crabs either to isosmotic seawater with low concentrations of an ion or to dilute seawater with high concentrations of an ion. Ca(2+) and Mg(2+) in combination affected MF levels. Finally, we found that the increase in MF levels was accelerated when hemolymph osmolality was precociously lowered by partially replacing hemolymph with deionized water prior to transferring animals to dilute seawater. Thus, the 6-8 h delay between exposing crabs to dilute sea water and observing an increase in MF appears to reflect the time needed for specific hemolymph ions to decrease below a threshold concentration.