Satureja hortensis L. essential oil causes Acinetobacter baumannii membrane disruption

Essential oils are promising antimicrobial agents against various bacteria, including Acinetobacter baumannii, a highly resistant clinical opportunistic pathogen with an increasing prevalence. The traditional application of the aromatic and medicinal plant Satureja hortensis L. (Lamiaceae) as a natural remedy for the treatment of inflammatory diseases, nausea, diarrhea, and various infectious diseases is well known. The aim of the study was to determine the antimicrobial activity and potential target site for S. hortensis essential oil against A. baumannii. The effect of the essential oil was determined using the microdilution broth method. The determined minimal inhibitory concentration (MIC=1 µl mL-1) showed that S. hortensis essential oil possesses a significant anti-A. baumannii effect. The A. baumannii reference strain ATCC 19606 cells in the exponential growth phase were treated for 3 h at 37 °C with MIC of S. hotensis essential oil and examined by scanning electron microscopy. The electron micrographs highlighted the occurrence of collapsed cells with perforations, cell content leakage, cell debris, but also cell autoaggregation (Fig. 1B). The autoaggregation was further confirmed by an autoaggregation test: untreated cells (Fig. 1A) were partially autoaggregative, while the treated cells were highly autoaggregative, as a result of changes of the cell surface properties. Thus, the essential oil affected the membrane systems of A. baumannii cells, causing structural changes of the bacterial cells. Since A. baumannii strains are susceptible to S. hortensis essential oil, the oil possesses a great potential in the control of growth of this species

Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm

Ostreolysin A6 (OlyA6) is a protein produced by the oyster mushroom (Pleurotus ostreatus). It binds to membrane sphingomyelin/cholesterol domains, and together with its protein partner, pleurotolysin B (PlyB), it forms 13-meric transmembrane pore complexes. Further, OlyA6 binds 1000 times more strongly to the insect-specific membrane sphingolipid, ceramide phosphoethanolamine (CPE). In concert with PlyB, OlyA6 has potent and selective insecticidal activity against the western corn rootworm. We analysed the histological alterations of the midgut wall columnar epithelium of western corn rootworm larvae fed with OlyA6/PlyB, which showed vacuolisation of the cell cytoplasm, swelling of the apical cell surface into the gut lumen, and delamination of the basal lamina underlying the epithelium. Additionally, cryo-electron microscopy was used to explore the membrane interactions of the OlyA6/PlyB complex using lipid vesicles composed of artificial lipids containing CPE, and western corn rootworm brush border membrane vesicles. Multimeric transmembrane pores were formed in both vesicle preparations, similar to those described for sphingomyelin/cholesterol membranes. These results strongly suggest that the molecular mechanism of insecticidal action of OlyA6/PlyB arises from specific interactions of OlyA6 with CPE, and the consequent formation of transmembrane pores in the insect midgut

Living in darkness: Exploring adaptation of Proteus anguinus in 3 dimensions by X-ray imaging

Background: Lightless caves can harbour a wide range of living organisms. Cave animals have evolved a set of morphological, physiological, and behavioural adaptations known as troglomorphisms, enabling their survival in the perpetual darkness, narrow temperature and humidity ranges, and nutrient scarcity of the subterranean environment. In this study, we focused on adaptations of skull shape and sensory systems in the blind cave salamander, Proteus anguinus, also known as olm or simply proteus—the largest cave tetrapod and the only European amphibian living exclusively in subterranean environments. This extraordinary amphibian compensates for the loss of sight by enhanced non-visual sensory systems including mechanoreceptors, electroreceptors, and chemoreceptors. We compared developmental stages of P. anguinus with Ambystoma mexicanum, also known as axolotl, to make an exemplary comparison between cave- and surface-dwelling paedomorphic salamanders. Findings: We used contrast-enhanced X-ray computed microtomography for the 3D segmentation of the soft tissues in the head of P. anguinus and A. mexicanum. Sensory organs were visualized to elucidate how the animal is adapted to living in complete darkness. X-ray microCT datasets were provided along with 3D models for larval, juvenile, and adult specimens, showing the cartilage of the chondrocranium and the position, shape, and size of the brain, eyes, and olfactory epithelium. Conclusions: P. anguinus still keeps some of its secrets. Our high-resolution X-ray microCT scans together with 3D models of the anatomical structures in the head may help to elucidate the nature and origin of the mechanisms behind its adaptations to the subterranean environment, which led to a series of troglomorphisms

A contribution to the Slovenian spider fauna – II

The present study reports on and discusses new records for the Slovenian spider fauna, namely: Asthenargus bracianus , Clubiona leucaspis , Euryopis laeta , Lasa eola prona , Lathys stigmatisata , Meioneta innotabilis , Oecobius maculatus , Porrhomma microphthalmum , Trichoncus saxicola and Zodarion pusio . According to their areas of distribution and confirmed presence in the neighbouring countries, the presence of newl y recorded species in Slovenia can be considered as expected, indicating still incomplete knowledge of Slovenian spider fauna

Prispevek k favni pajkov Slovenije

Sixteen spider species, new to the Slovenian fauna, have been recorded: Aphantaulax trifasciata, Araneus triguttatus, Arctosa cinerea, Cnephalocotes obscurus, Helophora insignis, Heriaeus hirtus, Nomisia exornata, Nurscia albomaculata, Pardosa agricola, Pardosa pratiuaga, Pardosa proxima, Phrlodromus longipalprs, Runcinia grammica, Theridula gonygaster Xysticus ninnii and Zora armillata. Recent records on presumably extinct endemic species Nesticus idriacus are also provided, as well as suggestion to its transfer to the IUCN category rare (R)

A contribution to the knowledge of the spider fauna of the wider Haloze region (northeast Slovenia)

A list of spider species collected in the wider Haloze region during the summer of 2002 is given. Altogether, 76 species belonging to 54 genera and 22 familles were recorded at 43 localities, representing the first comprehensive spider list of Haloze. Dipoena braccata (Theridiidae) and Scotophaeus scutulatus (Ganphosidae) are new records for the Slovenian fauna. In addition,the water spider (Argyroneta aquahèa), a vulnerable species in Slovenia, was found in one of the Drava River branches

Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae), a new record for Slovenian fauna from Postonjska jama cave

Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae), a new record for Slovenian fauna from Postonjska ! jama cav