SummaryPseudomonas aeruginosa causes serious acute and chronic infections in humans. Major differences exist in disease pathogenesis, clinical treatment and outcomes between acute and chronic infections. P. aeruginosa acute infection characteristically involves the type III secretion systems (T3SS) while chronic infection is often associated with the formation of biofilms, a major cause of difficulties to eradicate chronic infections. The choice between acute and chronic infection or the switch between them by P. aeruginosa is controlled by regulatory pathways that control major virulence factors and genes associated with biofilm formation. In this study, we characterized a hybrid sensor kinase PA1611 that controls the expression of genes associated with acute and chronic infections in P. aeruginosa PAO1. Expression of PA1611 completely repressed T3SS and swarming motility while it promoted biofilm formation. The protein PA1611 regulates two small RNAs (sRNAs), rsmY and rsmZ which in turn control RsmA. Independent of phosphate relay, PA1611 interacts directly with RetS in vivo. The positive effect of RetS on factors associated with acute infection could presumably be restrained by PA1611 when chronic infection conditions are present. This RetS-PA1611 interaction, together with the known RetS-GacS interaction, may control disease progression and the lifestyle choice of P. aeruginosa.

The dermaseptin peptides, mainly derived from the skin secretions of Hylidae frogs, belong to a superfamily of antimicrobial peptides and exhibit diverse antimicrobial and anticancer activities with low cytotoxicity. Here, we reported a novel dermaseptin peptide, from the South American orange-legged leaf frogs, Pithecopus (Phyllomedusa) hypochondrialis, processing the shortest peptide length, namely Dermaseptin-PH. The complementary DNA (cDNA) encoding biosynthetic precursor of Dermaseptin-PH was initially identified by the rapid amplification of cDNA ends PCR (RACE-PCR) technique from the skin secretion. The predicted primary structure was confirmed by a combination of reverse-phase high performance liquid chromatography (RP-HPLC) and MS/MS fragmentation from the skin secretion. Chemically-synthetic Dermaseptin-PH was investigated using a range of bioactivity assessment assays to evaluate the biological activities and cytotoxicity of Dermaseptin-PH. Dermaseptin-PH inhibited the growth of Gram-negative bacteria, Gram-positive bacteria, and pathogenic yeast Candida albicans. In addition, Dermaseptin-PH showed a broad-spectrum of anticancer activities against several cancer cell lines including MCF-7, H157, U251MG, MDA-MB-435S, and PC-3. The potent antimicrobial and anticancer activities of Dermaseptin-PH make it a promising candidate in the discovery of new drugs for clinical applications, and the relatively short sequence of Dermaseptin-PH can provide new insight for the research and structural modification of new peptide drugs.

Pseudomonas aeruginosa is an opportunistic pathogen capable of group behaviors including swarming motility and biofilm formation. Swarming motility plays an important role in the bacterium's spread to new environments, attachment to surfaces, and biofilm formation. Bacterial biofilm is associated with many persistent infections and increased resistance to antibiotics. In this study, we tested the effect of a 2-alkyl-4(1H)-quinolone (AHQ) signal, the Pseudomonas quinolone signal (PQS) on P. aeruginosa swarming and biofilm formation. Our results show that PQS repressed the swarming motility of P. aeruginosa PAO1. Such repression was independent of its cognate receptor PqsR and was not related to changes in the flagellae, type IV pili or the production of the surface-wetting agent rhamnolipid surfactant. While PQS did not affect twitching motility in PAO1, a pqsR deletion abolished twitching motility, indicating that pqsR is required for twitching motility. Our results also indicate that the enhancement of biofilm formation by PQS is at least partially dependent on the GacAS-Rsm regulatory pathway but does not involve the las or rhl QS systems.

the generation of Airy beams, it is highly desirable to locally control the amplitude and phase of the output beam simultaneously so as to satisfy the polynary amplitude and binary phase distributions. Traditional methods to generate an Airy beam usually require a complex and bulky optical system, such as a Fourier transform (FT) lens and a spatial light modulator, [3,6] or an FT lens and an FT plane, [7] which is against a high-density optical integration on a chip.Metamaterials and their 2D versions, metasurfaces, have provided an unprecedented approach to locally manipulate the phase, [10,11] amplitude, [12,13] and/ or polarization [14] of the electromagnetic (EM) waves. Recent studies have demonstrated that, manipulating the amplitude and phase simultaneously and independently leads to new wavefront manipulation effects and applications. [15][16][17] Inspired by the flexibility of introducing complex field distributions, [18] various Airy beam generators, either for free-space light, [19][20][21][22][23][24][25] or surface plasmons, [20,[26][27][28][29][30] have been proposed and demonstrated based on metasurfaces. Different from the metasurface lenses or holograms that merely require phase modulation, controlling both the amplitude and phase simultaneously is highly required to generate high-quality Airy beams that are capable of keeping good nondiffracting nature and stable full width half-maximum (FWHM) during propagation. [23] Typically, wavelength-scale engineered gratings, [26,29] graded nanocavity array, [27,28] and nanoslit resonators [20,30] are widely used to generate plasmonic Airy plasmons. In parallel with the above advances, free-space Airy beams, have been successfully realized by using dielectric nanofins, [21] metal nanorods, [23] and C-shaped apertures. [19,22,24,25] All these meta-atoms provide us with a robust tool to control the wave front of output beams appreciably across a resonance, and hence can be utilized to generate Airy beams. Since the building blocks of these metasurfaces are typically some resonant structures so that the amplitude and phase cannot be kept to satisfy an Airy function at frequencies out of the resonance frequency, such schemes thus exhibit limited working bandwidths around the resonance frequency. While promising steps have been taken to broaden the working bandwidth with proper design of C-aperture metasurface, and the working bandwidth of the Airy beams can be somewhat expanded around the resonance frequency, [22,24] the transmission efficiencies are typically lowThe Airy beam has attracted considerable research interest owing to the intriguing diffraction-free, self-accelerating, and self-healing properties, and hence has found numerous applications in photonics. Metasurfaces provide a compact method to generate Airy beams, but the available Airy beam generators suffer from the issue of narrow bandwidth since they typically rely on resonance principles. Here, hyperbolic metamaterials (HMMs) are proposed to address this issue by taking advantage of the broadba...