Anti-biofilm forming and anti-quorum sensing activity of selected essential oils and their main components on food-related micro-organisms.

AIMS: The aim of this study was to investigate the effect of clary sage, juniper, lemon and marjoram essential oils (EOs) and their major components on the formation of bacterial and yeast biofilms and on the inhibition of AHL-mediated quorum sensing (QS). METHODS AND RESULTS: Biofilm formation was measured by crystal violet and resazurin staining, and QS inhibition was detected by paper disc diffusion assay. Marjoram EO inhibited Bacillus cereus, Pichia anomala, Pseudomonas putida and mixed-culture biofilm formation of Ps. putida and Escherichia coli and showed the best QS inhibitor effect on Chromobacterium violaceum. For B. cereus, all components showed better antibiofilm capacity than the parent EOs. Lemon EO inhibited E. coli and mixed-culture biofilms, and cinnamon was effective against the mixed forms. Scanning electron microscopy showed the loss of three-dimensional structures of biofilms. CONCLUSIONS: The EOs and components used seem to be good candidates for prevention of biofilm formation and inhibition of the AHL-mediated QS mechanism. SIGNIFICANCE AND IMPACT OF THE STUDY: Biofilm formation on foods and food industrial equipment is a serious problem causing food spoilage and emergence of foodborne diseases. This article highlights the importance of studying EOs as potential disinfectants and food preservatives.

A comprehensive molecular phylogeny of the Mortierellales (Mortierellomycotina) based on nuclear ribosomal DNA.

The basal fungal order Mortierellales constitutes one of the largest orders in the basal lineages. This group consists of one family and six genera. Most species are saprobic soil inhabiting fungi with the ability of diverse biotransformations or the accumulation of unsaturated fatty acids, making them attractive for biotechnological applications. Only few studies exist aiming at the revelation of the evolutionary relationships of this interesting fungal group. This study includes the largest dataset of LSU and ITS sequences for more than 400 specimens containing 63 type or reference strains. Based on a LSU phylogram, fungal groups were defined and evaluated using ITS sequences and morphological features. Traditional morphology-based classification schemes were rejected, because the morphology of the Mortierellales seems to depend on culture conditions, a fact, which makes the identification of synapomorphic characters tedious. This study belongs to the most comprehensive molecular phylogenetic analyses for the Mortierellales up to date and reveals unresolved species and species complexes.

[Morphologic identification of mummified tissue traces]. / Morphologische Identifizierung mumifizierter Gewebsspuren.

Post mortem tissue samples from various human organs (skin, muscle, liver, kidney, brain) were stored at room temperature for a period of one year. During this time the samples were regularly histologically tested. Without any pretreatment of the samples a histological preparation and identification was no longer possible after only a few hours. By the use of a rehydration solution consisting of absolute ethanol (30 ml), aqua dest. (50 ml) and 0.2 M phosphate buffer pH 7.0 (20 ml) a reconstitution and identification was again possible. Further immunhistochemical examinations were also unaffected by the solution. The use of microwave stimulation allowed a reduction of the rehydration process from 24 hours to only 4 hours.

[Unusual suicides with chain saws]. / Ungewöhnliche Suizide mit Bandsägen.

Two cases of suicide with bandsaws, undertaken by workers in carpenters' workshops are reported and discussed. Their choice of this method was based on the fact that they knew how dangerous such machines were. Both cases were watched by witnesses, who could not intervene due to the speed of the events. It was possible to exclude accident or homicide.

Diethylene glycol (DEG)-associated myocardial changes: a pilot investigation of chronic intoxication in guinea-pigs.

The myocardium of guinea pigs fed on sublethal doses of diethylene glycol (DEG) over a period of 2-11 days was examined for microscopical and ultrastructural changes. Coagulative myocytolysis and loss of myofibrils, not observed in the controls, was patchily distributed throughout the myocardium. The accompanying ultrastructural features included swelling, pleomorphism and hyperplasia of mitochondria with an associated distension of the interfibrillary spaces and a displacement, distortion and rupture of adjacent myofibrils.

[Ultrastructural pathology of mechanical skeletal muscle damage]. / Zur Ultrastruktur-Pathologie mechanischer Skelettmuskelschädigungen.

In continuation of previous light microscope investigations the question has been raised whether the criteria determined for vital muscle damage using light microscopy, could be verified and perhaps extended for the ultrastructural region. In addition to existing human pathological material taken early post mortem, muscle tissue obtained from animal experiments was also examined. The evaluation concentrated on the muscle cells, the cell organelles and the contractile apparatus. An evaluation of semi-thin-sections was carried out in parallel. The following reaction patterns could be defined as vital reactions: hypercontraction bands, zones of rupture in narrow topological relationship to organelle changes, microstructure changes with disintegration of the fibre structure, subsarcolemmic and interfibrillary oedema, decomposition of the sarcolemma. The earliest vital reactions were detectable after only a few minutes survival time. The comparison between the results of animal experiments and human pathology and the application of the results to forensic pathology will be discussed.

[Forensic medicine and toxicologic aspects of 2-propanol poisoning]. / Rechtsmedizinische und toxikologische Aspekte bei Propanol-2-Intoxikationen.

Two cases of poisoning with 2-propanol (isopropylalcohol) are reported. In one case, nail polish remover was drunk by a 2-year-old child. The concentration of 2-propanol and its metabolite acetone in the blood could be observed over a period of approximately 50 h. The highest concentration of 2-propanol determined was 4.22 g/l. Acetone reached a maximum value of 2.27 g/l 12 h after ingestion. The child survived without any observable after-effects. In the second case, a 35-year-old man drank ethanol in addition to 2-propanol. The poisoning was lethal. The possible time of intake before death is discussed in relation to the estimated levels of ethanol, 2-propanol and acetone found in the blood and urine. The histomorphological findings are often important as well with regard to time of intake.