Three Dimensional Quantitative Structure-Activity Relationships of Sulfonamides Binding Monoclonal Antibody by Comparative Molecular Field Analysis

The three-dimensional quantitative structure-activity relationship (3D-QSAR) model of sulfonamide analogs binding a monoclonal antibody (MabSMR) produced against sulfamerazine, was carried out by comparative molecular field analysis (CoMFA). The affinities of MabSMR, expressed as Log10IC50, for 17 sulfonamide analogs were determined by competitive fluorescence polarization immunoassay (FPIA). Removal of two outliers from the initial set of 17 sulfonamide analogs improved the predictability of the models. The 3D-QSAR model of 15 sulfonamides resulted in q2cv values of 0.600, and r2 values of 0.995, respectively. This novel study combining FPIA with CoMFA demonstrates that multidisciplinary research can be used as a useful tool to investigate antigen-antibody interactions and provide information required for design of novel haptens, which may result in new antibodies with properties already optimized by an antibody-based immunoassay

Investigation of Antigen-Antibody Interactions of Sulfonamides with a Monoclonal Antibody in a Fluorescence Polarization Immunoassay Using 3D-QSAR Models

A three-dimensional quantitative structure-activity relationship (3D-QSAR) model of sulfonamide analogs binding a monoclonal antibody (MAbSMR) produced against sulfamerazine was carried out by Distance Comparison (DISCOtech), comparative molecular field analysis (CoMFA), and comparative molecular similarity indices analysis (CoMSIA). The affinities of the MAbSMR, expressed as Log10IC50, for 17 sulfonamide analogs were determined by competitive fluorescence polarization immunoassay (FPIA). The results demonstrated that the proposed pharmacophore model containing two hydrogen-bond acceptors, two hydrogen-bond donors and two hydrophobic centers characterized the structural features of the sulfonamides necessary for MAbSMR binding. Removal of two outliers from the initial set of 17 sulfonamide analogs improved the predictability of the models. The 3D-QSAR models of 15 sulfonamides based on CoMFA and CoMSIA resulted in q2 cv values of 0.600 and 0.523, and r2 values of 0.995 and 0.994, respectively, which indicates that both methods have significant predictive capability. Connolly surface analysis, which mainly focused on steric force fields, was performed to complement the results from CoMFA and CoMSIA. This novel study combining FPIA with pharmacophore modeling demonstrates that multidisciplinary research is useful for investigating antigen-antibody interactions and also may provide information required for the design of new haptens

Future Directions in Food Safety*

Abstract The recent success that the USDA Food Safety Inspection Service has had in 2003 and 2004 of reversing the steadily increasing trend in Class 1 recalls is welcomed. In agreement with those statistics are the FSIS microbiological results for Escherichia coli O157:H7 in raw ground beef, which also showed a decrease in 2003. But there is much work to be done in food safety and much more to achieve. It is imperative that while addressing food-safety issues, we should understand the role that the environmental microbiology, public health epidemiology, aerobiology, molecular microbial ecology, occupational health, industrial processes, municipal water quality, and animal health have on food safety. Although it is a difficult task, a concerted effort by industry, academic, and governmental researchers can accomplish the goal. Here we discuss the future directions and applications in the distribution and spread of foodborne hazards, methods for microbial detection and differentiation, intervention strategies for farm pathogen reduction, targeting waste at animal production sites, considerations on antimicrobial resistance, food-safety storage and preparation strategies, food irradiation, new and emerging food-safety hazards, and quantitative microbial food-safety risk assessment. Although this does not comprise an exhaustive list of food-safety issues, these are the areas that, we think, require considerable attention by researchers. Not only we need to strive to improve food safety through new strategies, processes, and applications, but we also need to be flexible and observant to readily handle the new and emerging food-safety problems, whether they are within our borders or global. At present, the United States has one of the safest food-safety systems in place. However, although this is not a time for complacency, our research endeavors should be designed to keep pace with the food-safety needs of the future

Destruction of single species biofi lms of Escherichia coli or Klebsiella pneumoniae subsp. pneumoniae by dextranase, lactoferrin, and lysozyme

The aim of this work was to determine the destructive activity of dextranase, lactoferrin, and lysozyme, against single species biofi lms composed of either Klebsiella pneumoniae subsp. pneumoniae or Escherichia coli using the MBEC Assay. Luminescence measurements based on quantitation of the ATP present were used to determine the amount of biofi lm elimination and correlated with quantity of live bacteria present in the sample. The data were analyzed employing a two-way ANOVA and Bonferroni post-test. Treatments resulted in percentage reductions of E. coli biofi lms ranging from 73 to 98 %. Lactoferrin (40 μg/ml) produced a signifi cantly higher-percentage reduction than lysozyme (10 μg/ml) (P < 0.05), no other signifi cant differences occurred. Similar treatments resulted in percentage reductions of K. pneumoniae subsp. pneumoniae biofilms ranging from 51 to 100 %. Dextranase treatments produced a signifi cantly lower percentage reduction than all other materials (P < 0.05), no other signifi cant differences occurred. No material was capable of complete destruction of both single species biofi lms; however, low concentrations of lactoferrin and lysozyme each removed 100 % of the K. pneumoniae subsp. pneumoniae biofi lm. Low concentrations of lactoferrin or lysozyme might be benefi cial to prevent biofi lm formation by K. pneumoniae subsp. pneumoniae. [Int Microbiol 2012; 15(4):183-187

Effects of commercial selenium products on glutathione peroxidase activity and semen quality in stud boars

The aim of this study was to determine how dietary supplementation of inorganic and organic selenium affects the selenium concentration and glutathione peroxidase activity in blood and sperm of sexually mature stud boars. Twenty-four boars of the Large White, Landrace, Pietrain and Duroc breeds of optimal breeding age (on average 2.5 years old) were used. The study lasted 90 days. The boars were randomly assigned to one of three dietary treatment groups: T1 = control; no added selenium (n = 8 boars), T2 = added 0.3 ppm inorganic selenium (sodium selenite, Microgran (R) Se 1% BMP) (n = 8 boars), and T3 = added 0.3 ppm organic selenium (Se-yeast, Sel-Plex 2000 (R)) (n = 8 boars). The concentration of selenium was determined in whole blood and semen, while the activity of glutathione peroxidase (GPx) was measured in blood plasma and semen. In order to measure GPx activity in semen, reactivation of the enzymatic GPx activity was performed. The determined selenium concentration in blood was lowest in the non-supplemented group of boars. Blood plasma GPx activity was higher in boars fed organic selenium than in boars fed a diet without supplemented selenium. While the supplementation of sodium selenite significantly increased GPx activity in boar semen. The highest-concentration of selenium in semen at the end of the trial was determined in the group of boars supplemented with organic selenium, somewhat lower in boars fed supplemented inorganic selenium, and the lowest in the non-supplemented group of boars. The only significant difference between the selenite and Se-yeast diet supplementation was observed in the Se concentration of the semen. The supplementation of selenium affected semen quality, and organic selenium improved the progressive motility of the spermatozoa and increased their resistance in hypo-osmotic and thermal tests. The storage ability of short term preserved semen was improved by organic selenium supplementation, as well as also increasing the fertility rate in gilts

Antagonistic Effects of Lipids Against the Anti-Escherichia coli and Anti-Salmonella Activity of Thymol and Thymol-β-d-Glucopyranoside in Porcine Gut and Fecal Cultures In Vitro

Strategies are sought to reduce the carriage and dissemination of zoonotic pathogens and antimicrobial-resistant microbes within food-producing animals and their production environment. Thymol (an essential oil) is a potent bactericide in vitro but in vivo efficacy has been inconsistent, largely due to its lipophilicity and absorption, which limits its passage and subsequent availability in the distal gastrointestinal tract. Conjugation of thymol to glucose to form thymol-β-d-glucopyranoside can decrease its absorption, but in vivo passage of effective concentrations to the lower gut remains suboptimal. Considering that contemporary swine diets often contain 5% or more added fat (to increase caloric density and reduce dustiness), we hypothesized that there may be sufficient residual fat in the distal intestinal tract to sequester free or conjugated thymol, thereby limiting the availability and subsequent effectiveness of this biocide. In support of this hypothesis, the anti-Salmonella Typhimurium effects of 6 mM free or conjugated thymol, expressed as log10-fold reductions of colony-forming units (CFU) ml−1, were diminished 90 and 58%, respectively, following 24-h in vitro anaerobic fecal incubation (at 39°C) with 3% added vegetable oil compared to reductions achieved during culture without added oil (6.1 log10 CFU ml−1). The antagonistic effect of vegetable oil and the bactericidal effect of free and conjugated thymol against Escherichia coli K88 tested similarly were diminished 86 and 84%, respectively, compared to reductions achieved in cultures incubated without added vegetable oil (5.7 log10 CFU ml−1). Inclusion of taurine (8 mg/ml), bile acids (0.6 mg/ml), or emulsifiers such as polyoxyethylene-40 stearate (0.2%), Tween 20, or Tween 80 (each at 1%) in the in vitro incubations had little effect on vegetable oil-caused inhibition of free or conjugated thymol. Based on these results, it seems reasonable to suspect that undigested lipid in the distal gut may limit the effectiveness of free or conjugated thymol. Accordingly, additional research is warranted to learn how to overcome obstacles diminishing bactericidal activity of free and conjugated thymol in the lower gastrointestinal tract of food-producing animals

Research in graphic design

An invited and reviewed opinion piece about the current state of research in graphic/communication design

The impact of low erythrocyte density in human blood on the fitness and energetic reserves of the African malaria vector Anopheles gambiae

Background Anaemia is a common health problem in the developing world. This condition is characterized by a reduction in erythrocyte density, primarily from malnutrition and/or infectious diseases such as malaria. As red blood cells are the primary source of protein for haematophagous mosquitoes, any reduction could impede the ability of mosquito vectors to transmit malaria by influencing their fitness or that of the parasites they transmit. The aim of this study was to determine the impact of differences in the density of red blood cells in human blood on malaria vector (Anopheles gambiae sensu stricto) fitness. The hypotheses tested are that mosquito vector energetic reserves and fitness are negatively influenced by reductions in the red cell density of host human blood meals commensurate with those expected from severe anaemia. Methods Mosquitoes (An. gambiae s.s.) were offered blood meals of different packed cell volume(PCV) of human blood consistent with those arising from severe anaemia (15%) and normalPCV (50%). Associations between mosquito energetic reserves (lipid, glucose and glycogen)and fitness measures (reproduction and survival) and blood meal PCV were investigated. Results The amount of protein that malaria vectors acquired from blood feeding (indexed by haematin excretion) was significantly reduced at low blood PCV. However, mosquitoes feeding on blood of low PCV had the same oviposition rates as those feeding on blood of normal PCV, and showed an increase in egg production of around 15%. The long-term survival of An. gambiae s.s was reduced after feeding on low PCV blood, but PCV had no significant impact on the proportion of mosquitoes surviving through the minimal period required to develop and transmit malaria parasites (estimated as 14 days post-blood feeding). The impact of blood PCV on the energetic reserves of mosquitoes was relatively minor. Conclusions These results suggest that feeding on human hosts whose PCV has been depleted due to severe anaemia does not significantly reduce the fitness or transmission potential of malaria vectors, and indicates that mosquitoes may be able exploit resources for reproduction more efficiently from blood of low rather than normal PCV

Evaluation of Thymol-β-d-Glucopyranoside as a Potential Prebiotic Intervention to Reduce Carriage of Zoonotic Pathogens in Weaned and Feeder Pigs

The gut of food-producing animals is a reservoir for foodborne pathogens. Thymol is bactericidal against foodborne pathogens but rapid absorption of thymol from the proximal gut precludes the delivery of effective concentrations to the lower gut where pathogens mainly colonize. Thymol-β-d-glucopyranoside is reported to be more resistant to absorption than thymol in everted jejunal segments and could potentially function as a prebiotic by resisting degradation and absorption in the proximal gut but being hydrolysable by microbial β-glycosidase in the distal gut. Previous in vitro studies showed bactericidal effects of thymol-β-d-glucopyranoside against Campylobacter, Escherichia coli, and Salmonella enterica serovar Typhimurium in the presence but not absence of intestinal microbes expressing β-glycosidase activity, indicating that hydrolysis was required to obtain antimicrobial activity. Presently, the oral administration of thymol-β-d-glucopyranoside was studied to examine the effects on intestinal carriage of Campylobacter, E. coli, and S. Typhimurium in swine. The effects of thymol-β-d-glucopyranoside or thymol on antimicrobial sensitivity of representative E. coli isolates and characterized Salmonella strains were also explored. Results from two in vivo studies revealed little antimicrobial effects of thymol-β-d-glucopyranoside on Campylobacter, E. coli, or S. Typhimurium in swine gut. These findings add credence to current thinking that hydrolysis and absorption of thymol-β-d-glucopyranoside and thymol may be sufficiently rapid within the proximal gut to preclude delivery to the distal gut. Antibiotic susceptibilities of selected bacterial isolates and strains were mainly unaffected by thymol. Further research is warranted to overcome obstacles, preventing the delivery of efficacious amounts of thymol-β-d-glucopyranoside to the lower gut