Effect of Marine Polyunsaturated Fatty Acids on Biofilm Formation of Candida albicans and Candida dubliniensis

The effect of marine polyunsaturated fatty acids on biofilm formation by the human pathogens Candida albicans and Candida dubliniensis was investigated. It was found that stearidonic acid (18:4 n-3), eicosapentaenoic acid (20:5 n-3), docosapentaenoic acid (22:5 n-3) and docosahexaenoic acid (22:6 n-3) have an inhibitory effect on mitochondrial metabolism of both C. albicans and C. dubliniensis and that the production of biofilm biomass by C. dubliniensis was more susceptible to these fatty acids than C. albicans. Ultrastructural differences, which may be due to increased oxidative stress, were observed between treated and untreated cells of C. albicans and C. dubliniensis with formation of rough cell walls by both species and fibrillar structures in C. dubliniensis. These results indicate that marine polyunsaturated fatty acids may be useful in the treatment and/or prevention of biofilms formed by these pathogenic yeasts

Scaling of the distribution of fluctuations of financial market indices

We study the distribution of fluctuations over a time scale $\Delta t$ (i.e., the returns) of the S&P 500 index by analyzing three distinct databases. Database (i) contains approximately 1 million records sampled at 1 min intervals for the 13-year period 1984-1996, database (ii) contains 8686 daily records for the 35-year period 1962-1996, and database (iii) contains 852 monthly records for the 71-year period 1926-1996. We compute the probability distributions of returns over a time scale $\Delta t$, where $\Delta t$ varies approximately over a factor of 10^4 - from 1 min up to more than 1 month. We find that the distributions for $\Delta t \leq$ 4 days (1560 mins) are consistent with a power-law asymptotic behavior, characterized by an exponent $\alpha \approx 3$, well outside the stable L\'evy regime $0 < \alpha < 2$. To test the robustness of the S&P result, we perform a parallel analysis on two other financial market indices. Database (iv) contains 3560 daily records of the NIKKEI index for the 14-year period 1984-97, and database (v) contains 4649 daily records of the Hang-Seng index for the 18-year period 1980-97. We find estimates of $\alpha$ consistent with those describing the distribution of S&P 500 daily-returns. One possible reason for the scaling of these distributions is the long persistence of the autocorrelation function of the volatility. For time scales longer than $(\Delta t)_{\times} \approx 4$ days, our results are consistent with slow convergence to Gaussian behavior.Comment: 12 pages in multicol LaTeX format with 27 postscript figures (Submitted to PRE May 20, 1999). See http://polymer.bu.edu/~amaral/Professional.html for more of our work on this are

Fatal COVID-19 outcomes are associated with an antibody response targeting epitopes shared with endemic coronaviruses

The role of immune responses to previously seen endemic coronavirus epitopes in severe acute respiratory coronavirus 2 (SARS-CoV-2) infection and disease progression has not yet been determined. Here, we show that a key characteristic of fatal coronavirus disease (COVID-19) outcomes is that the immune response to the SARS-CoV-2 spike protein is enriched for antibodies directed against epitopes shared with endemic beta-coronaviruses, and has a lower proportion of antibodies targeting the more protective variable regions of the spike. The magnitude of antibody responses to the SARS-CoV-2 full-length spike protein, its domains and subunits, and the SARS-CoV-2 nucleocapsid also correlated strongly with responses to the endemic beta-coronavirus spike proteins in individuals admitted to intensive care units (ICU) with fatal COVID-19 outcomes, but not in individuals with non-fatal outcomes. This correlation was found to be due to the antibody response directed at the S2 subunit of the SARS-CoV-2 spike protein, which has the highest degree of conservation between the beta-coronavirus spike proteins. Intriguingly, antibody responses to the less cross-reactive SARS-CoV-2 nucleocapsid were not significantly different in individuals who were admitted to ICU with fatal and non-fatal outcomes, suggesting an antibody profile in individuals with fatal outcomes consistent with an original antigenic sin type-response

2,7-di-p-chlorobenzoylnaphtho[2 ' 3 '-4 : 5]thiepin: a conformationally flexible new host molecule showing solvatochromic effects

The title host molecule exhibits remarkable conformational flexibility in its crystalline inclusion compounds. The alteration in molecular conformation, between the red dioxane and yellow benzene clathrates, corresponds to a dramatic change in the boat conformation of the seven-membered thiepin ring and reorientation of the side chains

Exposure to anthrax toxin alters human leucocyte expression of anthrax toxin receptor 1

Anthrax is a toxin-mediated disease; the lethal effects of which are initiated by the binding of Protective antigen (PA) with one of three reported cell surface toxin receptors (ANTXR). Receptor binding has been shown to influence host susceptibility to the toxins. Despite this crucial role for ANTXR in the outcome of disease, and the reported immunomodulatory consequence of the anthrax toxins during infection, little is known about ANTXR expression on human leukocytes. We characterised the expression levels of ANTXR1 (TEM8) on human leukocytes using flow cytometry. In order to assess the effect of prior toxin exposure on ANTXR1 expression levels, leukocytes from individuals with no known exposure, those exposed to toxin through vaccination and convalescent individuals were analysed. Donors could be defined as either ‘low’ or ‘high’ expressers based on the percentage of ANTXR1 positive monocytes detected. Prior exposure to toxins appears to modulate ANTXR1 expression, exposure through active infection being associated with lower receptor expression. A significant correlation between low receptor expression and high anthrax toxin-specific IFNγ responses was observed in previously infected individuals. We propose that there is an attenuation of ANTXR1 expression post-infection which may be a protective mechanism that has evolved to prevent re-infection

Estimating on-farm methane emissions for sheep production on the Northern Tablelands: establishment of demonstration site

A 36-hectare demonstration site at Armidale on the Northern Tablelands of New South Wales has been established to give livestock producers a practical insight into the magnitude of carbon fluxes, especially methane (CH4), associated with crossbred lamb production. The site contains soil and topographical diversity typical of the region (pH 4.8–5.1 (1:5 CaCl2); soil organic carbon 1.2–3.8%; cation exchange capacity 3–41 meq/100g). The replicated study over two years will compare animal productivity and emissions of low stocking rate enterprises on a low fertility (hill) section of the site (3.7 DSE/ha) with those of high soil fertility enterprises on the more fertile alluvial flats (6.7 DSE/ha). An EM38 soil map and seven soil samples were used to characterise the soil diversity within the two landscapes and to block each landscape into three classes (A, B, C), with three paddocks/class. Monthly pasture (green and dead DM availability) and regular production data (liveweight gain, fat score, fecundity, wool and lamb carcass weights at slaughter) will be collected. These measures will be used in decision support tools to estimate total on-farm CH4 emissions, emission per unit product, and to conduct a life cycle analysis of the contrasting enterprises. It is intended to use the site as a regional reference point for effective integration of farm carbon, productivity and economic understandings