Our group and other researchers have already Mocetinostat chemical structure reported on the successful growth of high-quality ZnO NWs using a simple technique consisting in the oxidation of Zn metal films in ambient conditions [16–22]. The simplicity of the process, the low temperature required (close to 500°C), as well as the good quality of the obtained NWs make this method attractive for future nanodevice applications. It is noteworthy that many reports on the optical properties of ZnO nanorods and NWs point out to the apparition

of a deep-level emission (DLE) band in the visible, together with the near-band edge emission (NBE) in the UV. In this sense, to change their optical properties, PXD101 several studies on selleck chemicals llc emission tailoring of ZnO NWs exposed to an irradiation source have already been developed [23–25] but with contradictory outcomes. In particular, with regard to the optical response, Krishna and co-workers reported the occurrence of several bands in the visible region which were identified in the PL spectra of 15-keV energy Ar+-irradiated thin films. They indicated a strong detraction of the visible signal with respect to the UV emission

[26], and similar optical results were confirmed by Liao and co-authors in the case of 5 to 10 kV Ti-implanted ZnO NWs [27]. Besides the modification of the UV/visible intensity ratio, UV signal blueshift was found by Panigrahy for 2- to 5-keV Ar+-irradiated ZnO nanorods [28]. The UV blueshift was also detected in the cathodoluminescence (CL) spectra of ZnO NWs irradiated with 30-keV Ti+ ions. Nevertheless, in this case, the visible emission did not suffered changes with the implantation doses [29], contrary to the behavior observed by Wang et al. [30] who reported a complete disappearance of the visible

emission from ZnO NWs irradiated with 2-keV H+ ions. Hence, the modification of the luminescence properties of ZnO after irradiation experiments is still not clearly understood and, even less, after low energy irradiation experiments. In any case, it would be desired Selleck Vorinostat to tailor the ZnO NW emission by minimizing the visible emission and therefore improving the UV luminescence. This would be particularly important in the case of cost-effective growth procedures, for which the obtained ZnO NWs could present some important emissions in this spectral range. In this work, we present the results of exposing ZnO NWs to a low-energy (≤2 kV) Ar+ ion irradiation. These experiments require a relatively simple experimental setup where only a small high-vacuum chamber and an ion gun are needed. Our experimental results show that the irradiation gives rise to an increase of the UV emission with respect to the visible one. We base the explanation of these effects on the structural analysis performed on individual NWs.

This would enable the translucent IJs to be viewed beneath a fluorescent microscope and be scored qualitatively for the presence/absence of bacteria. Colonies of the gfp-tagged strain (called TT01gfp) were initially checked for fluorescence using a UV light box before overnight cultures were checked for gfp expression using a fluorescent microscope. This confirmed that the vast majority of cells in an overnight population of TT01gfp were expressing gfp (see Figure 1A). Phenotypic comparisons of TT01 and TT01gfp confirmed that there was no difference in

growth rate, bioluminescence, pigmentation or Fosbretabulin chemical structure virulence to insect larvae. Furthermore we also verified that TT01gfp was able to colonize IJ nematodes (see Figure 1B) with a transmission frequency identical click here to TT01 (between 80-85%). As has been previously shown, the TT01gfp bacteria were confirmed to occupy the proximal region of the nematode gut extending from just below the pharynx of the IJ (see Figure 1C). Figure 1 Visualization of P. luminescens TT01 gfp using fluorescent microscopy. A) Image of a population of TT01gfp cells from a ABT-263 ic50 culture grown for 24 hours statically at 30°C; B) IJs colonized with TT01gfp (note that > 80% of the IJs can be seen to be colonized with TT01gfp); C) a fluorescent

micrograph overlaid with a brightfield image of a single IJ confirming that the bacteria are located at the proximal end of the gut near the pharynx (p: pharynx; b: TT01gfp). Identification of TT01gfp

mutants affected in colonization of the IJ In this study we were using a qualitative screen that was designed to identify mutants that were affected in transmission frequency i.e. we were looking for mutants that colonized significantly fewer IJs than the 80% level observed with TT01gfp. Therefore TT01gfp was subjected to transposon mutagenesis using the Tn5 interposon Dimethyl sulfoxide delivered by plasmid pUT-Km2 and individual mutants were arrayed into 96 well plates and frozen. From this arrayed library 3271 mutants were screened for a defect in transmission frequency by growing the mutant on a lipid agar plate and inoculating the biomass with 30 surface-sterilized H. bacteriophora IJs. After 21 days incubation the new generation of IJs were collected and checked for colonization using a fluorescent microscope. In this way 40 mutants were identified as having a qualitative defect in transmission frequency i.e. <50% of the IJs were observed to be colonized by the mutant bacteria. Each mutant was then re-screened (in triplicate) and approximately 120 IJs in total from each mutant were individually examined using fluorescence in order to get a quantitative measure of transmission frequency. As a result we identified 10 mutants that reproducibly gave transmission frequencies of <35% (see Table 1). The gene that was interrupted in each mutant was identified (with the exception of #26 F7 and #32 F12) and the loci affected are shown in Figure 2.