Matěj Božik

Identification of microbiota associated with Pectinatella magnifica in South Bohemia

Abstract The bacterial diversity of Pectinatella magnifica colonies sampled from pounds in South Bohemia during the summer of 2012 was investigated. The bacterial counts determined after cultivation on modified yeast extract-tryptone agar (Oxoid) supplemented with glucose (1 g L−1) varied from 4.22 to 6.61 and from 1.30 to 6.85 log CFU/g for aerobes and anaerobes, respectively. Higher counts were found in the superficial structures of Pectinatella colonies than in the inner gelled mass. Neither a trend in bacterial numbers at the individual site during the season, nor correlations between bacterial counts in P. magnifica and the surrounding water were observed. Fifty-four isolates were identified by sequencing the 16S rRNA gene and through MALDI-TOF MS analysis. Species of Aeromonas and Aquitalea were the predominantly isolated bacteria, but members of Chryseobacterium, Herbaspirillum, Enterobacter, Lactococcus, Leuconostoc, Pseudomonas and Sphingomonas were also found. As listed genera are wildly distributed in different water, soil, and plant samples, we conclude thatPectinatella colonies are inhabited by environmental bacteria. Nevertheless, a symbiotic relationship of these bacteria with P. magnifica cannot be excluded.

Effect of sex on the nutritional value of house cricket, Acheta domestica L.

Since January 2018, insects have been recognised as novel foods in the EU, but their nutritional value varies, and factors affecting their nutritional composition have been debated. We investigated the effect of sex on the nutritional value and chemical composition of the house cricket (Acheta domestica L.). Both sexes were rich in protein and lipids. The proximate composition was partly influenced by sex; females contained a significantly higher amount of lipids (18.3-21.7 vs 12.9-16.1 g/100 g dry matter, p = 0.0001) and fewer proteins than males (61.2-64.9 vs 66.3-69.6 g/100 g dry matter, p = 0.0001). Males contained more chitin (p = 0.0015) and nitrogen chains (p = 0.0003) than females. Only the ash (p = 0.4314) and nitrogen-free extract (p = 0.4871) were uninfluenced by sex. Furthermore, nutrient quality expressed as essential amino acid (72.3-77.1), thrombogenicity (1.22-1.45), and atherogenicity indices (0.53-0.58) did not differ between sexes (p > 0.05).

Stress response of Escherichia coli to essential oil components – insights on low-molecular-weight proteins from MALDI-TOF

The antibacterial effects of essential oils and their components (EOCs) are usually attributed to effects on membranes and metabolism. Studies of the effects of EOCs on protein expression have primarily analysed proteins larger than 10 kDa using gel electrophoresis. In the present study, we used MALDI-TOF-MS to investigate the effects of EOCs on low-molecular-weight proteins. From 297 m/z features, we identified 94 proteins with important differences in expression among untreated samples, samples treated with EOCs, and samples treated with antibiotics, peroxide, or chlorine. The targets of these treatments obviously differ, even among EOCs. In addition to ribosomal proteins, stress-, membrane- and biofilm-related proteins were affected. These findings may provide a basis for identifying new targets of essential oils and synergies with other antibiotics.

Data on low-molecular weight proteins of Escherichia coli treated by essential oils components, tetracycline, chlorine and peroxide by MALDI-TOF MS

In this dataset we provide MALDI-TOF MS spectra of Escherichia coli. The data presented in this article are related to the article entitled “Stress response of Escherichia coli to essential oil components – insights on low-molecular-weight proteins from MALDI-TOF” (Božik et al., 2018) [1]. Essential oils and their components are known for their antibacterial effect. Many studies evaluated the effect of essential oil components (EOCs) on the cell wall, bacterial membranes, and energetic metabolism. But data about low molecular weight proteins (<20 kDa) are limited. Provided data are focused on bacterial response to EOCs; tetracycline, peroxide and chlorine was used as control as common antibiotic and disinfectant agents used against bacteria. These data describe the effect of tested substances to bacterial protein synthesis.

Insecticidal activity of two formulations of essential oils against the cereal leaf beetle

ABSTRACT Purpose: Plant-derived essential oils and their encapsulations have recently received increasing interest as an alternative to synthetic biopesticides suitable for integrated pest management and organic farming. In this study, combinations of essential oils (EO) from Rosmarinus officinalis with Cymbopogon citratus and Pelargonium graveolens with Thymus vulgaris in two formulations including encapsulate were tested for their potential for wheat protection against adults and larvae of Oulema melanopus (L.). Materials and methods: The chemical composition of the essential oils was analyzed by gas chromatography-mass spectrometry (GC-MS). Testing of insecticidal activity of the evaluated substances was conducted with 2.5 ml of tested combinations of EOs sprayed on the paper. Ten adults or larvae of O. melanopus were placed into a vessel. Control of mortality of O. melanopus specimens was assessed after 24 h after establishment of the experiment. Results and conclusions: Tarsal contact toxicity assay showed the effectiveness of EO in concentration against O. melanopus larvae and adults in both formulations (essential oil and encapsulation) causing 100% mortality within 24 h. These results indicate the great potential of these essential oils and their encapsulations for future use in crop protection against insect pests.