Bactericidal Activity of N-Chlorotaurine against Biofilm-Forming Bacteria Grown on Metal Disks

Many orthopedic surgeons consider surgical irrigation and debridement with prosthesis retention as a treatment option for postoperative infections. Usually, saline solution with no added antimicrobial agent is used for irrigation. We investigated the activity of N-chlorotaurine (NCT) against various biofilm-forming bacteria in vitro and thereby gained significant information on its usability as a soluble and well-tolerated active chlorine compound in orthopedic surgery. Biofilms of Staphylococcus aureus were grown on metal alloy disks and in polystyrene dishes for 48 h. Subsequently, they were incubated for 15 min to 7 h in buffered solutions containing therapeutically applicable concentrations of NCT (1%, 0.5%, and 0.1%; 5.5 to 55 mM) at 37°C. NCT inactivated the biofilm in a time- and dose-dependent manner. Scanning electron microscopy revealed disturbance of the biofilm architecture by rupture of the extracellular matrix. Assays with reduction of carboxanilide (XTT) showed inhibition of the metabolism of the bacteria in biofilms. Quantitative cultures confirmed killing of S. aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa biofilms on metal alloy disks by NCT. Clinical isolates were slightly more resistant than ATCC type strains, but counts of CFU were reduced at least 10-fold by 1% NCT within 15 min in all cases. NCT showed microbicidal activity against various bacterial strains in biofilms. Whether this can be transferred to the clinical situation should be the aim of future studies

Genetic variation and relationships among spring camelina (Camelina sativa, Brassicaceae) accessions of different origin

Camelina sativa L. is one of the oldest crops of the Brassicaceae family, first domesticated in the region of south-eastern Europe. It has regained interest as a very promising alternative oilseed crop with broad adaptability, a wide range of tolerances to pests and diseases, and low-input requirements. The genetic diversity in spring camelina proved to be limited, so the identification and characterization of genetic variations in germplasm originating from different sources is considered very useful for development of efficient breeding programmes. The aim of the study was to use SSR markers in order to investigate genetic variation of twenty spring camelina accessions of different origin and estimate their genetic relatedness. Forty-five individual samples were taken from each accession and used for amplification of SSR markers P4C11, P6E4 and LIB19. Percentage of polymorphic loci, number of alleles, effective number of alleles, expected heterozygosity and Shannon's information index were used to estimate genetic variation. The accessions expressed different levels of genetic variation. The highest variability was found in cultivar Zavolzskij, breeding line CK2X-7, cultivar NS Zlatka and breeding line CK2X-9. The most uniform were cultivar Pernice, and population Maslomania. AMOVA (analysis of molecular variance) showed that 64% of the total genetic variation was attributed to variance within accessions and 36% to variance among them. IBased on genetic distance, accessions were divided in two clades, which both were further divided in two subclades. Genetic distance analysis indicated that there was overlapping in certain breeding programs and exchange of breeding germplasm

Influence of poly-N-acetylglucosamine in the extracellular matrix on N-chlorotaurine mediated killing of Staphylococcus epidermidis

N–chlorotaurine (NCT) has recently been shown to have bactericidal activity against bacterial biofilm on metal discs (Coraca-Huber et al., 2014). In a biofilm, Staphylococcus epidermidis polymerizes poly-N-acetylglucosamine (PNAG) to form an extracellular matrix (ECM). Pseudomonas aeruginosa does not express this PNAG and has been shown to be highly susceptible to NCT. We compared the action of NCT on S. epidermidis 1457, a PNAG positive strain (SE1457) and S. epidermidis 1457- M10 an isogenic PNAG negative mutant (SE1457 M10). NCT-mediated killing was more effective and quicker on the PNAG negative strain SE1457 M10. Bacteria hidden in biofilms for prolonged periods of time were generally more susceptible than freshly formed biofilms. The differences in NCT-mediated killing might not be direct effects since NCT did not react with the monomeric N-acetylglucosamine, but might be explained by denser growth in the PNAG-containing biofilm produced by the wild type strain, which results in delayed penetration of NCT. The higher susceptibility of older biofilms to NCTmediated killing could be explained by more pronounced 3D architecture and subsequent larger surface area for interactions with NCT

Yield-related traits of 20 spring camelina genotypes grown in a multi-environment study in Serbia

Camelina sativa (L.) Crantz is one of the oldest oilseed crops in Europe. Over the last twenty years, it has reemerged as a very promising alternative oilseed crop. Camelina has broad environmental adaptability, a wide range of resistances to pests and diseases, low-input requirements, and multiple industrial and feed applications exist for its seed oil and meal. In a multi-environment study conducted in Serbia, seven yield-related traits, including plant height (PH), height to the first branch (HFB), number of lateral branches (NLB), number of seed capsules per plant (NSCP), number of seeds per plant (NSP), mass of seeds per plant (MSP), and the total percentage of oil in the seed (TPOS), were analyzed in 20 spring camelina accessions. The combination of two years, two locations, and two sowing dates (autumn and spring) resulted in eight different environments across which the performance of the accessions was evaluated. The aims of the study were (a) to provide a phenotypic characterization and performance evaluation of the camelina accessions, (b) to identify correlations between the selected traits, and (c) to determine the effect of environmental factors on the traits. Environments contributed to the largest proportion in the total variance, explaining approximately 90% of the variance for all traits, except for NLB (70.96%) and TPOS (42.56%). The additive main effects and multiplicative interaction model (AMMI) showed that the weather conditions, and seeding dates were the most influential environmental factor. Location had a minor to moderate effect on the investigated traits. Lines CK3X-7 and Maksimir had the highest seed yields, and CK2X–9 and CJ11X–43 had the highest seed oil contents. All four lines had good adaptability and yield stability, making them the most suitable candidates for cultivation in the environmental conditions of Serbia in southeastern Europe. The present results reveal a potential for developing higher-yielding camelina cultivars with increased seed oil content and improved adaptability to various environmental conditions.Supplementary Materials: [https://www.mdpi.com/article/10.3390/agronomy11050858/s1

New technologies in achieving heat and drought resilient oilseed production, the case of camelina

Camelina [Camelina sativa (L.) Crantz] also known as “false flax” or “gold of pleasure”, is a self-pollinated, annual oilseed that belongs to the Brassicaceae family. Camelina is native species of Eurasia, which is gaining interest world-wide due to its better cold, heat and drought tolerance, and less susceptibility to disease and pests than oilseed rape. The most of research work on camelina has been carried out in northern America and continental Europe. Consequently, there are not many data on evaluation of suitability of camelina genotypes for cultivation in southern Europe. Two breeding groups (IFVCNS and BOKU) and one group focusing on the agronomy development of the crop (DISTAL) just recently started research activities focusing on development of new genotypes more adapted for southern regions of Europe and evaluation of their productivity in these, more arid regions.The poster for this abstract is available here [http://fiver.ifvcns.rs/handle/123456789/2259

BEAM DEPLETION SPECTRA OF {K} ATOMS ATTACHED TO {Ar} CLUSTERS. EXPERIMENTAL MEASUREMENTS AND QUANTUM-CHEMISTRY CALCULATIONS

Author Institution: Institute of Experimental Physics, TU Graz, Petersgasse 16, 8010 Graz, Austria/EUWe have measured beam depletion spectra of potassium atoms and oligomers formed on large argon clusters via the pick-up technique. Unlike helium droplets, where spectral shifts and broadening induced by the droplet are small, unambiguous assignment of the transitions observed in argon (a stronger perturber causing correspondingly broader peaks and larger spectral shifts) is difficult. We tentatively assign the transitions based both on their position, and on their order of appearance as the dopant pressure in the pick-up cell is increased. Of particular interest is what we believe to be the transition already observed in gas-phase pump-probe photoionization experiments}, \textbf{257,} 356 (1996).} then assigned to a transition to a dissociative state (the so called B-state) of the doublet potassium trimer. To corroborate the assignment we computed the ground-state potential energy surface [QCISD(T) level] and vertical excitation energies (CASSCF level) of the doublet potassium trimer, which we also compare to the corresponding spectra, suitably energy-scaled, of the doublet sodium trimer

ELECTRONIC SPECTRA OF TRIPLET Rb2_{2} MOLECULES ON HELIUM NANODROPLETS. EFFECTS ON THE SPIN-ORBIT STATES

Author Institution: Institute of Experimental Physics, TU Graz, 8010 Graz, AustriaA beam of cold (0.4\,K) superfluid helium droplets, each consisting of several thousand He atoms, is used for production and spectroscopic investigation of cold Rb$_{2}$ molecules in their lowest triplet state. We have investigated the $^{3}\Pi_{\mathrm{g}}\leftarrow{^{3}\Sigma^{+}_{\mathrm{u}}}$ electronic absorption spectrum of Rb$_{2}$ at $\approx$13500\,cm$^{-1}$, as well as its dispersed emission spectra. The absorption spectrum only shows two unstructured peaks separated by $\approx$200\,cm$^{-1}$, and is well modeled with gas-phase potentials if an overall droplet-induced blue shift is included ($\approx$53\,cm$^{-1}$). Of three accessible spin-orbit components the one with $\Omega=1$ seems to be missing. This is confirmed by the emission spectra: The latter are sharp (confirming that emission occurs from the gas phase after separation from the droplet) and consequently much more detailed. We observe that such spectra can be modeled with emission from the $\Omega=0,2$ components alone and, for any given excitation frequency, only one component is needed. Vibrational populations in the excited states are more evenly distributed ($v^{\prime}=0..9$) when emission occurs from $\Omega =2$. In contrast, emission from $v^{\prime}=0$ is predominant in the $\Omega=0$ state, where the vibrational relaxation rate must therefore be higher. Atomic emission, corresponding to dissociation, is also present. Unlike the case of KRb, presented in the companion talk, no blue-shifted (singlet) emission is observed