Iron acquisition strategies employed by Staphylococcus lugdunensis

Iron is crucial for many cellular processes including DNA synthesis and respiration. The majority of iron in mammals is in heme within hemoproteins, inside cells, or transported through circulation by the glycoprotein transferrin, which constitutes the greatest iron source in serum. Limiting iron availability is an important facet of nutritional immunity to help prevent infection. Staphylococcus lugdunensis is a human skin commensal and opportunistic pathogen capable of causing a variety of infections, including particularly aggressive endocarditis. It is an emerging pathogen with elevated virulence compared to other species of coagulase-negative staphylococci. The versatility of S. lugdunensis to infect multiple niches and cause aggressive infection indicates that it likely adapts its cellular physiology to overcome host defenses, including iron limitation. In chapter 2, we demonstrate that, contrary to other staphylococci, S. lugdunensis does not produce a siderophore – small (kDa) iron-chelating molecules that strip iron from host glycoproteins, including transferrin, and deliver it to microorganisms. As such, serum is growth-inhibitory to S. lugdunensis, unless it is supplemented with an iron source. We have identified and characterized several iron-compound transport processes through inactivation of genes required for acquisition of each respective compound. S. lugdunensis transports the staphylococcal carboxylate siderophores staphyloferrin A and staphyloferrin B through Hts and Sir, respectively, and is able to directly appropriate siderophores produced by S. aureus when in coculture, to support its growth. Heme and hemoglobin-iron is acquired via Isd. In chapter 3, we demonstrate that hemolysis enhances growth in blood, in an Isd-dependent manner. An iron-regulated ATPase, FhuC, is required for import of several carboxylate and hydroxamate siderophores, whereas Sst1 transports catecholamine stress hormone-iron (ie. adrenaline, noradrenaline, dopamine). fhuC and sst1 mutants are impaired for growth in absence of hydroxamates and catecholamines, indicating additional substrates acquired by these are vital to S. lugdunensis. Using a novel systemic model of S. lugdunensis infection, we show that a isd fhuC sst mutant is significantly impaired in its ability to colonize internal murine organs, and cause sickness. We have detailed several iron-acquisition systems in S. lugdunensis and are first to show specific transporters are important for pathogenesis in the host

Slow and deliberate cooperation in the commons

We test how fast and slow thought processes affect cooperation for sustainability by manipulating time pressure in a dynamic common-pool resource experiment. Sustainable management of shared resources critically depends on decisions in the current period to leave enough stock so that future generations are able to draw on the remaining limited natural resources. An intertemporal common-pool resource game represents a typical dynamic for social dilemmas involving natural resources. Using one such game, we analyse decisions throughout time. We find that people in this context deplete the common resource to a greater extent under time pressure, which leads to greater likelihood of stock collapse. Preventing resource collapse while managing natural resources requires actively creating decision environments that facilitate the cognitive capacity needed to support sustainable cooperation

Triumphs, Challenges, and Strategies of Opening Up: OER course design and implementation at Passaic County Community College

This presentation will share experiences of faculty and college administrators related to the design and implementation of courses using Open Education Resources (OER). Details will be presented on the various team dynamics and approaches to OER course designs, as well as the effects of OER on teaching and learning. Passaic County Community College is implementing an OER initiative utilizing in-house innovation and expertise. The administrative OER support team all report to the same dean and work in close proximity. Administrators have good relationships with faculty champions from work on previous grant-funded projects. This unique infrastructure facilitates collaboration, flexibility, and efficiency. The OER team is anticipating that their efforts will not only save students money, but will also energize instruction and contribute to student success

Long-Term Results from Evaluation of Advanced New Construction Packages in Test Homes: Lake Elsinore, California

This report presents the long-term evaluation results from a hot-dry climate project that examines the room-to-room temperature conditions that exist in a high performance envelope, the performance of a simplified air distribution system, and a comparison of modeled energy performance with measured energy use. The project, a prototype house built by K. Hovnanian Homes' Ontario Group, is located in Lake Elsinore, Riverside County, California, and achieves a 50% level of whole house source energy savings with respect to the Building America (BA) Benchmark Definition 2009 (Hendron and Engebrecht 2010). Temperature measurements in three rooms indicate that the temperature difference between the measured locations and the thermostat were within recommendations 90.3% of the time in heating mode and 99.3% of the time in cooling mode. The air distribution system is operating efficiently with average delivered temperatures adequate to facilitate proper heating and cooling and only minor average temperature differences observed between the system's plenum and farthest register. Monitored energy use results for the house indicate that it is using less energy than predicted from modeling. A breakdown of energy use according to end use determined little agreement between comparable values

The use of virtual reality in air transport during a pandemic

Purpose: Considering the realities of the 21st century and the global COVID-19 pandemic, the article aims to present the pandemic's impact on transport processes in selected European countries and suggested using virtual reality in these processes. Findings: The data provided by the International Air Transport Association (IATA) shows that every day about one hundred thousand aircraft fly, carrying over 140 thousand tons of cargo in total. As far as passenger transport is concerned within the European Union territory alone, more than a billion people use air transport annually, which gives the daily average of almost three million passengers. With an average cruising speed of about 800 kilometers per hour, we can assume that air transport meets the time requirements. Practical Implications: Time is one of the key determinants in society's functioning and the economy on a European and global scale. This determinant of the implementation of specific tasks is, in many cases, the main determinant of decisions made. It is not without reason that the phrase "time is money" is in common use. Considering such perception of the reality of the first half of the 21st century, it is reasonable to consider what means of transport can meet the expectations related to saving time needed to transport people and goods. This is particularly important in times of disruptions caused by the COVID - 19 pandemic.peer-reviewe

Vitamin D-VDR signaling inhibits Wnt/beta-catenin-mediated melanoma progression and promotes anti-tumor immunity

1α,25-dihydroxyvitamin D3 signals via the Vitamin D Receptor (VDR). Higher serum vitamin D is associated with thinner primary melanoma and better outcome, although a causal mechanism has not been established. As melanoma patients commonly avoid sun exposure, and consequent vitamin D deficiency might worsen outcomes, we interrogated 703 primary melanoma transcriptomes to understand the role of vitamin D-VDR signalling and replicated the findings in TCGA metastases. VDR expression was independently protective for melanoma death in both primary and metastatic disease. High tumor VDR expression was associated with upregulation of pathways mediating anti-tumor immunity and correspondingly with higher imputed immune cell scores and histologically detected tumor infiltrating lymphocytes (TILs). High VDR expressing tumors had downregulation of proliferative pathways, notably Wnt/beta-catenin signaling. Deleterious low VDR levels resulted from promoter methylation and gene deletion in metastases. Vitamin D deficiency (< 25 nmol/l ~ 10 ng/ml) shortened survival in primary melanoma in a VDR-dependent manner. In vitro functional validation studies showed that elevated vitamin D-VDR signaling inhibited Wnt/beta-catenin signaling genes. Murine melanoma cells overexpressing VDR produced fewer pulmonary metastases than controls in tail vein metastasis assays. In summary, vitamin D-VDR signaling contributes to controlling pro-proliferative/immunosuppresive Wnt/beta-catenin signaling in melanoma and this is associated with less metastatic disease and stronger host immune responses. This is evidence of the causal relationship between vitamin D-VDR signaling and melanoma survival which should be explored as a therapeutic target in primary resistance to checkpoint blockade

The Analysis of Receptor-binding Cancer Antigen Expressed on SiSo Cells (RCAS1) immunoreactivity within the microenvironment of the ovarian cancer lesion relative to the applied therapeutic strategy

RCAS1 is involved in generating the suppressive profile of the tumor microenvironment that helps cancer cells evade immune surveillance. The status of the cells surrounding the cancer nest may affect both the progression of the cancer and the development of metastases. In cases of ovarian cancer, a large number of patients do not respond to the applied therapy. The patient’s response to the applied therapy is directly linked to the status of the tumor microenvironment and the intensity of its suppressive profile. We analyzed the immunoreactivity of RCAS1 on the cells present in the ovarian cancer microenvironment in patients with the disease; these cells included macrophages and carcinoma-associated fibroblasts. Later we analyzed the immunoreactivity levels within these cells, taking into consideration the clinical stage of the cancer and the therapeutic strategy applied, such as the number of chemotherapy regiments, primary cytoreductive surgery, or the presence of advanced ascites. In the patients who did not respond to the therapy we observed significantly higher immunoreactivity levels of RCAS1 within the cancer nest than in those patients who did respond; moreover, in the non-responsive patients we found RCAS1 within both macrophages and carcinoma-associated fibroblasts. RCAS1 staining may provide information about the intensity of the immuno-suppressive microenvironment profile found in cases of ovarian cancer and its intensity may directly relate to the clinical outcome of the disease

Altered effector function of peripheral cytotoxic cells in COPD

<p>Abstract</p> <p>Background</p> <p>There is mounting evidence that perforin and granzymes are important mediators in the lung destruction seen in COPD. We investigated the characteristics of the three main perforin and granzyme containing peripheral cells, namely CD8⁺T lymphocytes, natural killer (NK; CD56⁺CD3^-) cells and NKT-like (CD56⁺CD3⁺) cells.</p> <p>Methods</p> <p>Peripheral blood mononuclear cells (PBMCs) were isolated and cell numbers and intracellular granzyme B and perforin were analysed by flow cytometry. Immunomagnetically selected CD8+ T lymphocytes, NK (CD56⁺CD3^-) and NKT-like (CD56⁺CD3⁺) cells were used in an LDH release assay to determine cytotoxicity and cytotoxic mechanisms were investigated by blocking perforin and granzyme B with relevant antibodies.</p> <p>Results</p> <p>The proportion of peripheral blood NKT-like (CD56⁺CD3⁺) cells in smokers with COPD (COPD subjects) was significantly lower (0.6%) than in healthy smokers (smokers) (2.8%, p < 0.001) and non-smoking healthy participants (HNS) (3.3%, p < 0.001). NK (CD56⁺CD3^-) cells from COPD subjects were significantly less cytotoxic than in smokers (16.8% vs 51.9% specific lysis, p < 0.001) as were NKT-like (CD56⁺CD3⁺) cells (16.7% vs 52.4% specific lysis, p < 0.001). Both cell types had lower proportions expressing both perforin and granzyme B. Blocking the action of perforin and granzyme B reduced the cytotoxic activity of NK (CD56⁺CD3^-) and NKT-like (CD56⁺CD3⁺) cells from smokers and HNS.</p> <p>Conclusion</p> <p>In this study, we show that the relative numbers of peripheral blood NK (CD56⁺CD3^-) and NKT-like (CD56⁺CD3⁺) cells in COPD subjects are reduced and that their cytotoxic effector function is defective.</p

Sequential Metabolism of 7-Dehydrocholesterol to Steroidal 5,7-Dienes in Adrenal Glands and Its Biological Implication in the Skin

Since P450scc transforms 7-dehydrocholesterol (7DHC) to 7-dehydropregnenolone (7DHP) in vitro, we investigated sequential 7DHC metabolism by adrenal glands ex vivo. There was a rapid, time- and dose-dependent metabolism of 7DHC by adrenals from rats, pigs, rabbits and dogs with production of more polar 5,7-dienes as detected by RP-HPLC. Based on retention time (RT), UV spectra and mass spectrometry, we identified the major products common to all tested species as 7DHP, 22-hydroxy-7DHC and 20,22-dihydroxy-7DHC. The involvement of P450scc in adrenal metabolic transformation was confirmed by the inhibition of this process by DL-aminoglutethimide. The metabolism of 7DHC with subsequent production of 7DHP was stimulated by forscolin indicating involvement of cAMP dependent pathways. Additional minor products of 7DHC metabolism that were more polar than 7DHP were identified as 17-hydroxy-7DHP (in pig adrenals but not those of rats) and as pregna-4,7-diene-3,20-dione (7-dehydroprogesterone). Both products represented the major identifiable products of 7DHP metabolism in adrenal glands. Studies with purified enzymes show that StAR protein likely transports 7DHC to the inner mitochondrial membrane, that 7DHC can compete effectively with cholesterol for the substrate binding site on P450scc and that the catalytic efficiency of 3βHSD for 7DHP (Vm/Km) is 40% of that for pregnenolone. Skin mitochondria are capable of transforming 7DHC to 7DHP and the 7DHP is metabolized further by skin extracts. Finally, 7DHP, its photoderivative 20-oxopregnacalciferol, and pregnenolone exhibited biological activity in skin cells including inhibition of proliferation of epidermal keratinocytes and melanocytes, and melanoma cells. These findings define a novel steroidogenic pathway: 7DHC→22(OH)7DHC→20,22(OH)27DHC→7DHP, with potential further metabolism of 7DHP mediated by 3βHSD or CYP17, depending on mammalian species. The 5–7 dienal intermediates of the pathway can be a source of biologically active vitamin D3 derivatives after delivery to or production in the skin, an organ intermittently exposed to solar radiation