Potential of antimicrobial treatment of linear low-density polyethylene with poly((tert-butyl-amino)-methyl-styrene) to reduce biofilm formation in the food industry

Antimicrobial surfaces are one approach to prevent biofilms in the food industry. The aim of this study was to investigate the effect of poly((tert-butyl-amino)-methyl-styrene) (poly(TBAMS)) incorporated into linear low-density polyethylene (LLDPE) on the formation of mono- and mixed-species biofilms. The biofilm on untreated and treated LLDPE was determined after 48 and 168 h. The comparison of the results indicated that the ability of Listeria monocytogenes to form biofilms was completely suppressed by poly(TBAMS) (Δ_168 h 3.2 log₁₀ cfu cm^?2) and colonization of Staphylococcus aureus and Escherichia coli was significantly delayed, but no effect on Pseudomonas fluorescens was observed. The results of dual-species biofilms showed complex interactions between the microorganisms, but comparable effects on the individual bacteria by poly(TBAMS) were identified. Antimicrobial treatment with poly(TBAMS) shows great potential to prevent biofilms on polymeric surfaces. However, a further development of the material is necessary to reduce the colonization of strong biofilm formers.     

Engineered exosomes: A new promise for the management of musculoskeletal diseases

Background

Exosomes are nanovesicles actively secreted by potentially all cell types, including tumour cells, with the primary role of extracellular systemic communication mediators, both at autocrine and paracrine levels, at short and long distances. Recently, different studies have used exosomes as a delivery system for a plethora of different molecules, such as drugs, microRNAs and proteins. This has been made possible thanks to the simplicity in exosomes engineering, their great stability and versatility for applications in oncology as well as in regenerative medicine.

Cetirizine per os: exposure and antihistamine effect in the dog

Background

Cetirizine is an antihistamine used in dogs, but plasma concentrations in relation to effect after oral administration are not well studied. This study investigated cetirizine exposure and the plasma cetirizine concentration-antihistamine response relation in the dog following oral administration of cetirizine.

Results

Eight Beagle dogs were included in a cross-over study consisting of two treatments. In treatment one, cetirizine 2–4 mg/kg was administered per os once daily for 3 days. The other treatment served as a control. Wheal diameter induced by intra-dermal histamine injections served as response-biomarker. Cetirizine plasma concentration was quantified by UHPLC-MS/MS. Median (range) cetirizine plasma terminal half-life was 10 h (7.9–16.5). Cetirizine significantly inhibited wheal formation compared with the premedication baseline. Maximum inhibition of wheal formation after treatment with cetirizine per os was 100% compared with premedication wheal diameter. The median (range) IC₅₀-value for reduction in wheal area was 0.33 µg/mL (0.07–0.45). The median (range) value for the sigmoidicity factor was 1.8 (0.8–3.5). A behavioral study was also conducted and revealed no adverse effects, such as sedation.

Conclusion

The results indicate that a once-daily dosing regimen of 2–4 mg/kg cetirizine per os clearly provides a sufficient antihistamine effect. Based on this experimental protocol, cetirizine may be an option to treat histamine-mediated inflammation in the dog based on this experimental protocol but additional clinical studies are required.

     

Evaluation of detection distance‐dependent reflectance spectroscopy for the determination of the sun protection factor using pig ear skin

Determination of sun protection factors (SPFs) is currently an invasive method, which is based on erythema formation (phototest). Here we describe an optical setup and measurement methodology for the determination of SPFs based on diffuse reflectance spectroscopy, which measures UV‐reflectance spectra at 4 distances from the point of illumination. Due to a high spatial variation of the reflectance data, most likely due to inhomogeneities of the sunscreen distribution, data of 50 measurement positions are averaged. A dependence of the measured SPF on detection distance is significant for 3 sunscreens, while being inconclusive for 2 sunscreens due to high inter‐sample variations. Using pig ear skin samples (n=6), the obtained SPF of 5 different commercial sunscreens corresponds to the SPF values of certified test institutes in 3 cases and is lower for 2 sunscreens of the same manufacturer, suggesting a formulation specific reason for the discrepancy. The results demonstrate that the measurement can be performed with a UV dose below the minimal erythema dose. We conclude the method may be considered as a potential noninvasive in vivo alternative to the invasive in vivo phototest, but further tests on different sunscreen formulations are still necessary.

     

Factors Affecting Events During Oxidation of Low Density Lipoprotein: Correlation of Multiple Parameters of Oxidation

The present study shows that copper oxidation of LDL is a tightly-ordered process which can be finely controlled by appropriate selection of duration of oxidation and of concentrations of LDL and copper. Oxidation of LDL (0.1-2.0 mg LDL protein/ml) was carried out by copper catalysis (in the ratio of 2.5 μM Cu²⁺ to 0.1 mg LDL protein/ml) in phosphate-buffered saline, and was monitored by agarose gel electro-phoresis, gas chromatography (GC), anion exchange fast protein liquid chromatography (FPLC), fluorescence spectroscopy and dynamic light scattering. Analysis of the data showed strong cross correlations between many of the parameters of oxidation. Oxidation was more rapid for lower concentrations than for higher concentrations of LDL, despite the same ratio of copper to LDL being employed. Chemical kinetics analysis of the GC data suggested that 7β-hydroxycholesterol formation occurred as a first order (or pseudo first order) consecutive reaction to the oxidation of linoleate. The first order rate constants for decomposition of lioleate and production of 7β-hydroxycholesterol correlated closely with the theoretically-calculated times between collision of LDL particles. LDL particle diameter, measured by dynamic light scattering, increased by ca. 50% over 24 h oxidation, suggesting unfolding of apo B-100.

Prolonged oxidation of LDL at low concentration suggested that the radical chain reaction was able to propagate, albeit slowly, on cholesterol after all the polyunsaturated fatty acid was consumed. For higher concentrations of LDL, prolonged oxidation resulted in partial aggregation. These findings are applicable to preparing oxidised LDL with different degrees of oxidation, under controlled conditions, for studying its biological properties.     

Neuroendocrine control of pheromone production in moths

In many moth species regulation of pheromone production has been attributed to the timely release of a pheromone biosynthesis activating neuropeptide (PBAN). The gene encoding PBAN has been sequenced in two moth species. Immunochemical studies as well asin situ hybridization and Northern analysis of PBAN encoding mRNA have localized the neuroendocrine cells responsible for the production of PBAN and have traced the neuronal network of PBAN immunoreactivity. Release into the bloodstream has been demonstrated, the target tissue delineated, and the signal transduction pathway and its modulation analyzed. This paper reviews the current status of research concerning the neuroendocrine control of pheromone production in Lepidopterans and presents some recent developments concerning the receptors involved in the pheromonotropic activity. In this study, we report on the use of a biologically active photoaffinity-biotin-labeled derivative of PBAN N-[N-(4-azido-tetrafluorobenzoyl-biocytinyloxyl-succinimide) and show the presence of a protein (estimated molecular weight of 50 kDa) which specifically binds to PBAN in membrane preparations of pheromone glands. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No.2279-E, 1997 series     

On the phylogeny, expression and targeting of plant nucleoside diphosphate kinases

The plant nucleoside diphosphate kinase (NDPK, EC 2.7.4.6) gene family consists of three groups whose gene products are found in different subcellular locations. In this study we discuss the evolutionary history, localization and expression of the NDPK genes, addressing the question of functional specialization of the different NDPKs. A phylogenetic analysis revealed that the three NDPK isoforms were present already in the last common ancestor of vascular plants and mosses. Our data also imply that the NDPK3 genes possess a higher degree of conservation than the NDPK1 and NDPK2 genes. The expression levels of the different NDPKs in Arabidopsis thaliana inflorescences, leaves and roots were evaluated using quantitative PCR as well as in silico methods. This analysis showed that NDPK1 is the most highly expressed NDPK gene in all the studied tissues. NDPK3a has the second highest NDPK expression, while NDPK3b is expressed to a very low extent. However, expression of NDPK3b is elevated in inflorescence tissue. In situ hybridization experiments performed on inflorescences showed NDPK3a expression in actively dividing cells. NDPK3b expression was observed during later stages of flower development, specifically in the tapetum, ovules and petals. Additionally, we show that an NDPK3 protein is able to direct the green fluorescent protein to both mitochondria and chloroplasts using transient expression in leaf protoplasts. The dual localisation of NDPK3 was confirmed by Western blot, which also demonstrated that the majority of the NDPK3 protein is found in the mitochondria.     

Unprecedented Melioidosis Cases in Northern Australia Caused by an Asian Burkholderia pseudomallei Strain Identified by Using Large-Scale Comparative Genomics

Melioidosis is a disease of humans and animals that is caused by the saprophytic bacterium Burkholderia pseudomallei. Once thought to be confined to certain locations, the known presence of B. pseudomallei is expanding as more regions of endemicity are uncovered. There is no vaccine for melioidosis, and even with antibiotic administration, the mortality rate is as high as 40% in some regions that are endemic for the infection. Despite high levels of recombination, phylogenetic reconstruction of B. pseudomallei populations using whole-genome sequencing (WGS) has revealed surprisingly robust biogeographic separation between isolates from Australia and Asia. To date, there have been no confirmed autochthonous melioidosis cases in Australia caused by an Asian isolate; likewise, no autochthonous cases in Asia have been identified as Australian in origin. Here, we used comparative genomic analysis of 455 B. pseudomallei genomes to confirm the unprecedented presence of an Asian clone, sequence type 562 (ST-562), in Darwin, northern Australia. First observed in Darwin in 2005, the incidence of melioidosis cases attributable to ST-562 infection has steadily risen, and it is now a common strain in Darwin. Intriguingly, the Australian ST-562 appears to be geographically restricted to a single locale and is genetically less diverse than other common STs from this region, indicating a recent introduction of this clone into northern Australia. Detailed genomic and epidemiological investigations of new clinical and environmental B. pseudomallei isolates in the Darwin region and ST-562 isolates from Asia will be critical for understanding the origin, distribution, and dissemination of this emerging clone in northern Australia.     

Going with the grain: Fiber,cognition, and the microbiota-gut-brain-axis

Healthy dietary intake has been acknowledged for decades as one of the main contributors to health. More recently, the field of nutritional psychiatry has progressed our understanding regarding the importance of nutrition in supporting mental health and cognitive function. Thereby, individual nutrients, including omega-3 fatty acids and polyphenols, have been recognized to be key drivers in this relationship. With the progress in appreciating the influence of dietary fiber on health, increasingly research is focusing on deciphering its role in brain processes. However, while the importance of dietary fiber in gastrointestinal and metabolic health is well established, leading to the development of associated health claims, the evidence is not conclusive enough to support similar claims regarding cognitive function. Albeit the increasing knowledge of the impact of dietary fiber on mental health, only a few human studies have begun to shed light onto the underexplored connection between dietary fiber and cognition. Moreover, the microbiota-gut-brain axis has emerged as a key conduit for the effects of nutrition on the brain, especially fibers, that are acted on by specific bacteria to produce a variety of health-promoting metabolites. These metabolites (including short chain fatty acids) as well as the vagus nerve, the immune system, gut hormones, or the kynurenine pathway have been proposed as underlying mechanisms of the microbiota-brain crosstalk. In this minireview, we summarize the evidence available from human studies on the association between dietary fiber intake and cognitive function. We provide an overview of potential underlying mechanisms and discuss remaining questions that need to be answered in future studies. While this field is moving at a fast pace and holds promise for future important discoveries, especially data from human cohorts are required to further our understanding and drive the development of public health recommendations regarding dietary fiber in brain health.