Construction of the optical part of a time-of-flight detector prototype for the AFP detector.

We present the construction of the optical part of the ToF (time-of-flight) subdetector prototype for the AFP (ATLAS Forward Proton) detector. The ToF detector in conjunction with a 3D silicon pixel tracker will tag and measure protons originating in central exclusive interactions p + p → p + X + p, where the two outgoing protons are scattered in the very forward directions. The ToF is required to reduce so-called pileup backgrounds that arise from multiple proton interactions in the same bunch crossing at high luminosity. The background can fake the signal of interest, and the extra rejection from the ToF allows the proton tagger to operate at the high luminosity required for measurement of the processes. The prototype detector uses fused silica bars emitting Cherenkov radiation as a relativistic particle passes through it. The emitted Cherenkov photons are detected by a micro-channel plate multi-anode Photomultiplier Tube (MCP-PMT) and processed by fast electronics.

Streptococcus suis in invasive human infections in Poland: clonality and determinants of virulence and antimicrobial resistance.

The purpose of this study was to perform an analysis of Streptococcus suis human invasive isolates, collected in Poland by the National Reference Centre for Bacterial Meningitis. Isolates obtained from 21 patients during 2000-2013 were investigated by phenotypic tests, multilocus sequence typing (MLST), analysis of the TR9 locus from the multilocus variable number tandem repeat (VNTR) analysis (MLVA) scheme and pulsed-field gel electrophoresis (PFGE) of SmaI-digested DNA. Determinants of virulence and antimicrobial resistance were detected by polymerase chain reaction (PCR) and analysed by sequencing. All isolates represented sequence type 1 (ST1) and were suggested to be serotype 2. PFGE and analysis of the TR9 locus allowed the discrimination of four and 17 types, respectively. Most of the isolates were haemolysis- and DNase-positive, and around half of them formed biofilm. Genes encoding suilysin, extracellular protein factor, fibronectin-binding protein, muramidase-released protein, surface antigen one, enolase, serum opacity factor and pili were ubiquitous in the studied group, while none of the isolates carried sequences characteristic for the 89K pathogenicity island. All isolates were susceptible to penicillin, cefotaxime, imipenem, moxifloxacin, chloramphenicol, rifampicin, gentamicin, linezolid, vancomycin and daptomycin. Five isolates (24 %) were concomitantly non-susceptible to erythromycin, clindamycin and tetracycline, and harboured the tet(O) and erm(B) genes; for one isolate, lsa(E) and lnu(B) were additionally detected. Streptococcus suis isolated in Poland from human invasive infections belongs to a globally distributed clonal complex of this pathogen, enriched in virulence markers. This is the first report of the lsa(E) and lnu(B) resistance genes in S. suis.

The impact of copper ions on growth, lipid peroxidation, and phenolic compound accumulation and localization in lentil (Lens culinaris Medic.) seedlings.

Changes in phenolics (PhC) measured as UV-absorbing compounds (UVAC) and their localization as well as growth, lipid peroxidation (TBARS level), H(2)O(2) and Cu accumulation and other ions content in roots of two lentil cultivars (cv. Krak and cv. Tina) contrasting in Cu sensitivity were examined. The aim of this study was to reveal the importance of PhC in Cu tolerance. During Cu treatment, inhibition of growth and increases in lipid peroxidation in roots of both cultivars were observed, but the effects were more pronounced in cv. Tina (more sensitive) than in cv. Krak (less sensitive). Cu at 0.5 mM caused higher Cu and H(2)O(2) accumulation, but lower K(+) content and UVAC levels in the root tips of cv. Tina. Opposite changes were recorded in cv. Krak. Fluorescence microscopic analyses confirmed greater PhC accumulation in cv. Krak (less sensitive) than in cv. Tina (more sensitive) after Cu treatment and showed that these compounds accumulated particularly in vacuoles and the cell wall. Taken together, these results show that, in spite of the high concentration of Cu-stimulated PhC accumulation in cv. Krak, it was not sufficient to counteract the amount of ROS generated by the metal. The role of PhC in different reactions to Cu stress in lentil roots is discussed.

Melatonin applied to cucumber (Cucumis sativus L.) seeds improves germination during chilling stress.

The relationship between germination and melatonin applied during osmo- and hydropriming was studied in cucumber seeds. The proportion of nuclei with different DNA contents, the mean ploidy and the (2C + 4C = 8C)/2C ratio in unprimed and primed, dry and imbibed at 10 degrees C seeds were established by flow cytometry. Thiobarbituric acid reactive substances and protein oxidation were also estimated. Melatonin and indole-3-acetic acid (IAA) concentrations in the seeds were determined using high-performance liquid chromatography with electrochemical detection. Being sensitive to chilling stress, seeds that germinated well (99%) at 25 degrees C showed only 30% germination at 15 degrees C, and almost no germination (4%) at 10 degrees C. Hydropriming in water improved seed germination to 50-60% at 15 degrees C and the addition of melatonin (25-100 M) also increased the rate of germination. Osmopriming in polyethylene glycol increased germination at 15 degrees C to 78%, and 98% when combined with 50 M melatonin. Osmoprimed seeds germinated even at 10 degrees C and reached 43%, and 83% when 50 M melatonin was applied. None of the treatments induced DNA synthesis, although during the first 24 hr of imbibition at 10 degrees C the mean ploidy and the (2C + 4C = 8C)/2C ratio increased, which is indicative of the advanced Phase II of germination. Hydro- and osmopriming slightly decreased IAA content in the seeds in most of the cases; only hydropriming with 100 and 500 M melatonin increased it. Melatonin protected membrane structure against peroxidation during chilling, but excessive melatonin levels in cucumber seeds (approximately 4 microg/g fresh weight) provoked oxidative changes in proteins. There is still lack of information explained clearly the role of melatonin in plant physiology. This molecule acts multidirectionally and usually is alliged to other compounds.

Antioxidant enzymes activity and phenolic compounds content in red cabbage seedlings exposed to copper stress.

The phenolics: anthocyanin (ATH), sinapoyl esters and activity of antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POX), ascorbate peroxidase (APX), glutathione peroxidase (GPX) and glutathione reductase (GR), in red cabbage seedlings subjected to Cu2+ stress were investigated. Cu2+ at low doses (0.5 mM), increased the levels of ATH and sinapoyl derivatives in red cabbage. High Cu2+ concentration (2.5 mM) provoked oxidative stress and enhanced thiobarbituric acid reactive substances (TBARS) content in tissues. A lower level of TBARS was correlated with high ATH content. It seems that synthesis of these isoflavonoids is an effective strategy against reactive oxygen species (ROS). The analysis of the antioxidant enzymes activity suggested that peroxidases were the most active enzymes in red cabbage seedlings exposed to Cu2+ stress. It could results from the fact that phenolic compounds (PhC), which could be also substrates for different peroxidases, were the first line of defence against metal stress.

White yellow virescent pattern in winter rye: inheritance, plant growth, and ultrastructure of plastids.

Inbred lines from different varieties of cultivated plants characterized by a white yellow irregular pattern on the leaves obtained after selection in the inbred generation (S3) of winter rye (Secale cereale L.) were the object of the present studies. The feature of a white yellow irregular pattern in all lines was monomeric and recessive. This trait in L158b, wch, and zp was determined by the same recessive gene marked with the symbol wyv1, "white yellow virescent." The gene responsible for the appearance of the above feature in line L24 was nonallelic to the gene wyv1, therefore it was designated as the sequent gene of the same series--wyv2. The studied forms of plants were characterized by a diminution in the number of plastids and in chlorophyll (a plus b) content in mesophyll cells of leaves. Contrary to typical ultrastructure of chloroplasts in dark green plants (control), plastids in lines with the white yellow virescent pattern on the leaves showed variations in ultrastructure from numerous granal and intergranal thylakoids to a reduced number.

1-Amino-2-phenylethylphosphonic acid: an inhibitor of L-phenylalanine ammonia-lyase in vitro.

L(-)-, and D(+)-enantiomers of 1-amino-2-phenylethylphosphonic acid (PheP), a phosphonic analogue of phenylalanine, inhibit the activity of L-phenylalanine ammonia-lyase (EC 4.3.1.5) of potato tuber tissue in vitro. The apparent type of inhibition depends on concentration of PheP; as the concentration of D-PheP is raised from 10(-5) M to 2.5 X 10(-3) M, the type of inhibition shifts from competitive through mixed and non-competitive to uncompetitive. L-PheP exerts either a competitive or mixed-type inhibition at low (10(-6)-10(-5) M) or moderate (5 X 10(-5)-2 X 10(-4) M) concentration. Ki for the concentration range of competitive inhibition were 6.5 X 10(-6) M, 5.3 X 10(-5)M and 1.6 X 10(-5) M for L-, D-, and D,L-PheP, respectively. These Ki values are valid for a relatively narrow range of L-Phe concentration (0.2-4 mM) as L-phenylalanine ammonia-lyase does not follow the Michaelis-Menten kinetics of the reaction.