Changes in the proteomes of the hemocytes and fat bodies of the flesh fly Sarcophaga bullata larvae after infection by Escherichia coli

Background  

Insects have an efficient self-defense system that is based on innate immunity. Recent findings have disclosed many parallels between human and insect innate immunity, and simultaneously fine differences in the processes between various species have been revealed. Studies on the immune systems of various insect species may uncover the differences in their host defense strategies.     

Comparison of the antiplasmodial and falcipain-2 inhibitory activity of β-amino alcohol thiolactone-chalcone and isatin-chalcone hybrids

The synthesis and biological evaluation of two novel series of natural-product-like hybrids based on the chalcone, thiolactone and isatin scaffolds is herein described. Results for a 36-member β-amino alcohol triazole library showed that the thiolactone-chalcones, with IC₅₀s ranging from 0.68 to 6.08 μM, were more active against W2 strain Plasmodium falciparum than the isatin-chalcones with IC₅₀s of 14.9 μM or less. Also of interest is falcipain-2 inhibitory activity displayed by the latter, whereas the thiolactone-chalcones lacked enzyme inhibitory activity.     

A review on comparative data concerning <Emphasis Type="Italic">Fusarium</Emphasis> mycotoxins in Bt maize and non-Bt isogenic maize

The European corn borer reportedly promotes the infection of maize by Fusarium spp. Stalk and ear rots caused by Fusarium spp. are often related to mycotoxin accumulation in maize kernels. As a result, food and animal feed from maize are more severely contaminated with Fusarium mycotoxins: e.g. fumonisins (FUM), deoxynivalenol (DON) and zearalenone (ZEA). Bt maize is primarily an important potential tool for insect pest protection, both in the European Union and in other countries. Bt maize carrying the Bt genes is highly resistant to European corn borer larval feeding due to Bt toxin (δ toxin) production. Effective measures to combat pests therefore often have a positive side-effect in that they also reduce mycotoxin levels. Comparative analysis was used to the evaluation of the studies dealing with the reduction of Fusarium mycotoxins in Bt maize. Nineteen out of 23 studies on Bt maize came to the conclusion that Bt maize is less contaminated with mycotoxins (FUM, DON, ZEA) than the conventional control variety in each case.     

Alterations in serum selenium levels and their relation to troponin I in acute myocardial infarction

Selenium (Se) is an essential trace element with antioxidant function. The aim of the present study was to estimate the alterations of Se serum level during the acute phase of myocardial infarction and its relation to biomarkers of myocardial necrosis. Serum Se levels were measured at admission and after 24 h in 60 consecutive patients with acute coronary syndrome (both with and without ST elevation). Troponin I (TnI) was assessed at admission and then twice daily for 3 days; patients with normal levels were excluded. Fifty-five patients with acute MI (positive TnI) were included into the analysis. During the first day of hospitalization, patients received standard therapy, including acetylsalicylic acid, clopidogrel, and heparin or enoxaparin; all underwent urgent coronary angiography and percutaneous intervention, when appropriate. Mean Se levels at baseline and 24 h later were comparable (67.1 ± 2.1 vs. 67.2 ± 1.8 μg/L, ns). Linear regression has shown significant correlation between baseline Se levels and peak TnI (y = 3.4x ? 116, r ² = 0.13, P = 0.008). Positive correlation was found also between the peak TnI and the difference from baseline to 24 h (y = 2.2x + 115, r ² = 0.08, P = 0.04). Moreover, close negative correlation was observed between baseline Se levels and the difference from baseline to 24 h (y = ?0.9x + 62.7, r ² = 0.55, P<0.001). Our results have shown marked individual changes in Se levels during the acute phase of MI as well as correlation between Se levels and peak TnI. These results suggest that alterations in serum Se may be related to the extent of myocardial infarction.     

Enhancing oral vaccine potency by targeting intestinal M cells

The immune system in the gastrointestinal tract plays a crucial role in the control of infection, as it constitutes the first line of defense against mucosal pathogens. The attractive features of oral immunization have led to the exploration of a variety of oral delivery systems. However, none of these oral delivery systems have been applied to existing commercial vaccines. To overcome this, a new generation of oral vaccine delivery systems that target antigens to gut-associated lymphoid tissue is required. One promising approach is to exploit the potential of microfold (M) cells by mimicking the entry of pathogens into these cells. Targeting specific receptors on the apical surface of M cells might enhance the entry of antigens, initiating the immune response and consequently leading to protection against mucosal pathogens. In this article, we briefly review the challenges associated with current oral vaccine delivery systems and discuss strategies that might potentially target mouse and human intestinal M cells.     

Comparative proteomic profiling of culture filtrate proteins of less and highly virulent Francisella tularensis strains

The facultative intracellular bacterium Francisella tularensis is the causal agent of the serious infectious disease tularemia. Despite the dynamic progress, which has been made in last few years, important questions regarding Francisella pathogenicity still remain to be answered. Generally, secreted proteins play an important role in pathogenicity of intracellular microbes. In this study, we investigated the protein composition of the culture filtrate proteins of highly virulent F. tularensis subsp. tularensis, strain SCHU S4 and attenuated F. tularensis subsp. holarctica, live vaccine strain using a comparative proteomic analysis. The majority of proteins identified in this study have been implicated in virulence mechanisms of other pathogens, and several have been categorized as having moonlighting properties; those that have more than one unrelated function. This profiling study of secreted proteins resulted in the unique detection of acid phosphatase (precursor) A (AcpA), β-lactamase, and hypothetical protein FTT0484 in the highly virulent strain SCHU S4 secretome. The release of AcpA may be of importance for F. tularensis subsp. tularensis virulence due to the recently described AcpA role in the F. tularensis escape from phagosomes.     

Monitoring of dimethyl sulphate-induced N3-methyladenine, N7-methylguanine and O(6)-methylguanine DNA adducts using reversed-phase high performance liquid chromatography and mass spectrometry

This work describes the determination of N3-methyladenine, N7-methylguanine and O(6)-methylguanine adducts in dimethyl sulphate-treated salmon-testes DNA employing reversed-phase high performance liquid chromatography (RP-HPLC) with UV-vis detection, followed by mass-spectrometric verification using electrospray ionisation in positive mode ESI(+). Within validation parameters, accuracy, precision, calibration parameters, limit of detection (LOD) and quantitation (LOQ) as well as stability of standard stock solutions were tested and presented for UV/vis detection. The limit of detection (LOD) was found to be 0.1 ng/mL for N3-methyladenine and 0.2 ng/mL for both N7-methylguanine and O(6)-methylguanine (S/N=3). The limit of quantitation (LOQ) was found to be 0.5 ng/mL for all measured compounds, (S/N=10). Quantitative results were obtained for each substance based on eight-point calibration. Intra- and inter-day precisions were within 1.73-6.96 and 2.26-7.58%, respectively, and correlation coefficients of calibration curves (R(2)) ranged from 0.9992 to 0.9997. Relative proportion of N7-methylguanine was accounted for 61.53+/-2.97% (R.S.D.=4.8), N3-methyladenine for 38.19+/-2.99% (R.S.D.=9.6) and O(6)-methylguanine for 0.29+/-0.02% (R.S.D.=5.1), respectively. The application of the above-mentioned techniques provides a valuable contribution for simultaneous determination of methylated DNA adducts, and may represent a suitable approach for similar monitoring/screening studies.     

Vascular endothelial growth factor in astroglioma stem cell biology and response to therapy

Malignant astrogliomas are among the most aggressive, highly vascular and infiltrating tumours bearing a dismal prognosis, mainly due to their resistance to current radiation treatment and chemotherapy. Efforts to identify and target the mechanisms that underlie astroglioma resistance have recently focused on candidate cancer stem cells, their biological properties, interplay with their local microenvironment or 'niche', and their role in tumour progression and recurrence. Both paracrine and autocrine regulation of astroglioma cell behaviour by locally produced cytokines such as the vascular endothelial growth factor (VEGF) are emerging as key factors that determine astroglioma cell fate. Here, we review these recent rapid advances in astroglioma research, with emphasis on the significance of VEGF in astroglioma stem-like cell biology. Furthermore, we highlight the unique DNA damage checkpoint properties of the CD133-marker-positive astroglioma stem-like cells, discuss their potential involvement in astroglioma radioresistance, and consider the implications of this new knowledge for designing combinatorial, more efficient therapeutic strategies.     

Effect of protein degradation on spot M(r) distribution in 2-D gels--a case study of proteolysis during development of Streptomyces coelicolor cultures

Proteolysis, a regulated biological process, is reflected by protein spot molecular weight distribution in 2-D gel electrophoretograms. Here we report studies of Streptomyces cultures as they undergo two different developmental processes involving proteolysis. Systematic changes in protein molecular weight distribution between the control samples and those with high activity of proteases were demonstrated. The observations were supported by a numerical model of degradation and its influence on the M(r) distribution. Simple statistics could be used to distinguish between normal and degradative 2-D gel electrophoretic patterns.     

The POM Monoclonals: A Comprehensive Set of Antibodies to Non-Overlapping Prion Protein Epitopes

PrP^Sc, a misfolded and aggregated form of the cellular prion protein PrP^C, is the only defined constituent of the transmissible agent causing prion diseases. Expression of PrP^C in the host organism is necessary for prion replication and for prion neurotoxicity. Understanding prion diseases necessitates detailed structural insights into PrP^C and PrP^Sc. Towards this goal, we have developed a comprehensive collection of monoclonal antibodies denoted POM1 to POM19 and directed against many different epitopes of mouse PrP^C. Three epitopes are located within the N-terminal octarepeat region, one is situated within the central unstructured region, and four epitopes are discontinuous within the globular C-proximal domain of PrP^C. Some of these antibodies recognize epitopes that are resilient to protease digestion in PrP^Sc. Other antibodies immunoprecipitate PrP^C, but not PrP^Sc. A third group was found to immunoprecipitate both PrP isoforms. Some of the latter antibodies could be blocked with epitope-mimicking peptides, and incubation with an excess of these peptides allowed for immunochromatography of PrP^C and PrP^Sc. Amino-proximal antibodies were found to react with repetitive PrP^C epitopes, thereby vastly increasing their avidity. We have also created functional single-chain miniantibodies from selected POMs, which retained the binding characteristics despite their low molecular mass. The POM collection, thus, represents a unique set of reagents allowing for studies with a variety of techniques, including western blotting, ELISA, immunoprecipitation, conformation-dependent immunoassays, and plasmon surface plasmon resonance-based assays.