Evaluation of the Efficacy of 1-octen-3-ol and Carbon Dioxide Chemoattractants with Mosquitoes and Bloodmeal Analysis of \u3ci\u3eCulex\u3c/i\u3e Mosquito spp. in Lancaster County, Nebraska

The purpose of mosquito-borne disease surveillance is to assess the risk of pathogen transmission by assessing mosquito populations and the prevalence of disease pathogens in those populations. West Nile virus (WNV) is an important mosquito-borne virus in Nebraska, and can be transmitted by several mosquito species found in Lancaster County, Nebraska, including Culex pipiens L., Culex salinarius Coquillett, Culex restuans Theobald, Culex tarsalis Coquillett, Culex territans Walker, and Culex erraticus Dyar & Knab. These species are ornithophilic, yet many studies indicate a shift in host feeding to mammalian in late summer months. One-octen-3-ol (octenol) can be isolated from bovine breath and mammalian sweat, mimicking a mammalian host. Here we present findings of a two year study. A chemoattractant study using CDC light traps baited with either dry ice, 1 octenol gel pack, 6 octenol gel packs, 10 ml of liquid octenol, 20 ml of liquid octenol, or no attractant. Our results demonstrated that traps with CO2 collected more mosquitoes than traps with octenol or no attractant. In the bloodmeal analysis, humans were the primary host. We were not able to detect a host shift in host use from avian to mammalian utilizing octenol as a chemoattractant as the majority of bloodmeals were human. Advisor: Roberto Cortinas and Gary Brewe

Evaluation of the Efficacy of 1-octen-3-ol and Carbon Dioxide Chemoattractants with Mosquitoes and Bloodmeal Analysis of \u3ci\u3eCulex\u3c/i\u3e Mosquito spp. in Lancaster County, Nebraska

The purpose of mosquito-borne disease surveillance is to assess the risk of pathogen transmission by assessing mosquito populations and the prevalence of disease pathogens in those populations. West Nile virus (WNV) is an important mosquito-borne virus in Nebraska, and can be transmitted by several mosquito species found in Lancaster County, Nebraska, including Culex pipiens L., Culex salinarius Coquillett, Culex restuans Theobald, Culex tarsalis Coquillett, Culex territans Walker, and Culex erraticus Dyar & Knab. These species are ornithophilic, yet many studies indicate a shift in host feeding to mammalian in late summer months. One-octen-3-ol (octenol) can be isolated from bovine breath and mammalian sweat, mimicking a mammalian host. Here we present findings of a two year study. A chemoattractant study using CDC light traps baited with either dry ice, 1 octenol gel pack, 6 octenol gel packs, 10 ml of liquid octenol, 20 ml of liquid octenol, or no attractant. Our results demonstrated that traps with CO2 collected more mosquitoes than traps with octenol or no attractant. In the bloodmeal analysis, humans were the primary host. We were not able to detect a host shift in host use from avian to mammalian utilizing octenol as a chemoattractant as the majority of bloodmeals were human. Advisor: Roberto Cortinas and Gary Brewe

Cellulose as an Inert Scaffold in Plasmon-Assisted Photoregeneration of Cofactor Molecules

Plasmonic nanoparticles exhibit excellent light-harvesting properties in the visible spectral range, which makes them a convenient material for the conversion of light into useful chemical fuel. However, the need for using surface ligands to ensure colloidal stability of nanoparticles inhibits their photochemical performance due to the insulating molecular shell hindering the carrier transport. We show that cellulose fibers, abundant in chemical functional groups, can serve as a robust substrate for the immobilization of gold nanorods, thus also providing a facile way to remove the surfactant molecules. The resulting functional composite was implemented in a bioinspired photocatalytic process involving dehydrogenation of sodium formate and simultaneous photoregeneration of cofactor molecules (NADH, nicotinamide adenine dinucleotide) using visible light as an energy source. By systematic screening of experimental parameters, we compare photocatalytic and thermocatalytic properties of the composite and evaluate the role of palladium cocatalyst.M.G. acknowledges funding from the Spanish MINECO (grant MAT2013-49375-EXP) and the BBVA Foundation "Primera convocatoria de ayudas fundacion BBVA a investigadores, innovadores y creadores culturales". N.T.-S. acknowledges the support from the BioTechNan (NCBiR) program of interdisciplinary PhD studies at Wroclaw University of Science and Technology as well as the support from the Photonics and Bionanotechnology Association (PhoBiA). The work was also financed by a statutory activity subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Wroclaw University of Science and Technology. S.V. D. and V. P. acknowledge the support by the Spanish Ministry of Science, Innovation, and Universities (project BIO2017-88030-R), Maria de Maeztu Units of Excellence Program from the Spanish State Research Agency grant no. MDM-2017-0720

Quadratic and Cubic Nonlinear Optical Properties of Salts of Diquat-Based Chromophores with Diphenylamino Substituents

A series of chromophoric salts has been prepared in which 4-(diphenylamino)phenyl (Dpap) electron donor groups are connected to electron-accepting diquaternized 2,2′-bipyridyl (diquat) units. The main aim is to combine large quadratic and cubic nonlinear optical (NLO) effects in potentially redox-switchable molecules with 2D structures. The chromophores have been characterized as their PF_6^− salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. The visible absorption spectra are dominated by intense π → π* intramolecular charge-transfer (ICT) bands, and all of the compounds show two reversible or quasireversible diquat-based reductions and partially reversible Dpap oxidations. Single crystal X-ray structures have been obtained for one salt and for the precursor compound (E)-4-(diphenylamino)cinnamaldehyde, both of which adopt centrosymmetric space groups. First hyperpolarizabilities β have been measured by using hyper-Rayleigh scattering (HRS) with a 800 nm laser, and Stark (electroabsorption) spectroscopy of the ICT bands affords estimated static first hyperpolarizabilities β_0. The directly and indirectly derived β values are large and generally increased substantially for the bis-Dpap derivatives when compared with their monosubstituted analogues. Polarized HRS studies show that the NLO responses of the disubstituted species are dominated by “off-diagonal” β_(zyy) components. Lengthening the diquaternizing alkyl unit lowers the electron-acceptor strength and therefore increases the ICT energies and decreases the E_(1/2) values for diquat reduction. However, compensating increases in the ICT intensity prevent significant decreases in the Stark-based β_0 responses. Cubic NLO properties have been measured by using the Z-scan technique over a wavelength range of 520−1600 nm, revealing relatively high two-photon absorption cross-sections of up to 730 GM at 620 nm for one of the disubstituted chromophores

Spontaneous formation of liquid crystalline phases and phase transitions in highly concentrated plasmid DNA

The liquid crystalline (LC) properties of two supercoiled plasmid DNA samples, pBSK (2958 bp) and pGEM (3000 bp), have been studied using polarised light microscopy (PLM), circular dichroism (CD) and UV-Vis spectroscopy. The influence of methods of isolation on plasmid LC behaviour is described, and using PLM we have demonstrated the spontaneous formation of cholesteric fingerprint-like textures. Preliminary studies of LC phase transitions in pGEM show the irreversibility of LC phase formation, as a consequence of changes in the tertiary structure of supercoiled plasmids. Using UV-Vis spectroscopy a hyperchromic effect was observed with increasing temperature. The CD spectra clearly showed structural changes, and probably mismatching of DNA bases, during cooling. Finally, we have observed an irreversible phase transition in plasmid DNA which is very different from that previously reported in linear DNA

Ecological and morphological differentiation among COI haplotype groups in the plant parasitic nematode species \u3ci\u3eMesocriconema xenoplax\u3c/i\u3e

DNA barcoding with the mitochondrial COI gene reveals distinct haplotype subgroups within the monophyletic and parthenogenetic nematode species, Mesocriconema xenoplax. Biological attributes of these haplotype groups (HG) have not been explored. An analysis of M. xenoplax from 40 North American sites representing both native plant communities and agroecosystems was conducted to identify possible subgroup associations with ecological, physiological, or geographic factors. A dataset of 132 M. xenoplax specimens was used to generate sequences of a 712 bp region of the cytochrome oxidase subunit I gene. Maximum-likelihood and Bayesian phylogenies recognized seven COI HG (≥99/0.99 posterior probability/bootstrap value). Species delimitation metrics largely supported the genetic integrity of the HG. Discriminant function analysis of HG morphological traits identified stylet length, total body length, and stylet knob width as the strongest distinguishing features among the seven groups, with stylet length as the strongest single distinguishing morphological feature. Multivariate analysis identified land cover, ecoregion, and maximum temperature as predictors of 53.6% of the total variation (P = 0.001). Within land cover, HG categorized under “herbaceous,” “woody wetlands,” and “deciduous forest” were distinct in DAPC and RDA analyses and were significantly different (analysis of molecular variance P = 0.001). These results provide empirical evidence for molecular, morphological, and ecological differentiation associated with HG within the monophyletic clade that represents the species Mesocriconema xenoplax

The role of the light source in antimicrobial photodynamic therapy

This work was financially supported by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant (agreement no. 764837) and NCN Opus grant no. 2019/35/B/ST4/03280. We are also grateful to the Engineering and Physical Sciences Research Council of the UK for financial support from grants EP/R511778/1 and EP/L015110/1.Antimicrobial photodynamic therapy (APDT) is a promising approach to fight the growing problem of antimicrobial resistance that threatens health care, food security and agriculture. APDT uses light to excite a light-activated chemical (photosensitiser), leading to the generation of reactive oxygen species (ROS). Many APDT studies confirm its efficacy in vitro and in vivo against bacteria, fungi, viruses and parasites. However, the development of the field is focused on exploring potential targets and developing new photosensitisers. The role of light, a crucial element for ROS production, has been neglected. What are the main parameters essential for effective photosensitiser activation? Does an optimal light radiant exposure exist? And finally, which light source is best? Many reports have described the promising antibacterial effects of APDT in vitro, however, its application in vivo, especially in clinical settings remains very limited. The restricted availability may partially be due to a lack of standard conditions or protocols, arising from the diversity of selected photosensitising agents (PS), variable testing conditions including light sources used for PS activation and methods of measuring anti-bacterial activity and their effectiveness in treating bacterial infections. We thus sought to systematically review and examine the evidence from existing studies on APDT associated with the light source used. We show how the reduction of pathogens depends on the light source applied, radiant exposure and irradiance of light used, and type of pathogen, and so critically appraise the current state of development of APDT and areas to be addressed in future studies. We anticipate that further standardisation of the experimental conditions will help the field advance, and suggest key optical and biological parameters that should be reported in all APDT studies. More in vivo and clinical studies are needed and are expected to be facilitated by advances in light sources, leading to APDT becoming a sustainable, alternative therapeutic option for bacterial and other microbial infections in the future.Publisher PDFPeer reviewe

Treatment of antibiotic-resistant bacteria colonizing diabetic foot ulcers by OLED induced antimicrobial photodynamic therapy

KM, KJP and IDWS were supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant (Agreement N°764837) and NCN Opus Grant No. 2019/35/B/ST4/03280.We evaluate the efficacy of antimicrobial Photodynamic Therapy (APDT) for inactivating a variety of antibiotic-resistant clinical strains from diabetic foot ulcers. Here we are focused on APDT based on organic light-emitting diodes (OLED). The wound swabs from ten patients diagnosed with diabetic foot ulcers were collected and 32 clinical strains comprising 22 bacterial species were obtained. The isolated strains were identified with the use of mass spectrometry coupled with a protein profile database and tested for antibiotic susceptibility. 74% of isolated bacterial strains exhibited adaptive antibiotic resistance to at least one antibiotic. All strains were subjected to the APDT procedure using an OLED as a light source and 16 µM methylene blue as a photosensitizer. APDT using the OLED led to a large reduction in all cases. For pathogenic bacteria, the reduction ranged from 1.1-log to > 8 log (Klebsiella aerogenes, Enterobacter cloaca, Staphylococcus hominis) even for high antibiotic resistance (MRSA 5-log reduction). Opportunistic bacteria showed a range from 0.4-log reduction for Citrobacter koseri to > 8 log reduction for Kocuria rhizophila. These results show that OLED-driven APDT is effective against pathogens and opportunistic bacteria regardless of drug resistance.Publisher PDFPeer reviewe

Efficient singlet oxygen photogeneration by zinc porphyrin-dimers upon one- and two-photon excitation

Funding: UK EPSRC (EP/L017008/1), IDWS acknowledges a Royal Society Wolfson Research Merit Award. This work is a part of the ITN-EJD-2017 project POLYTHEA which has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement 764837.The development of photodynamic therapy at depth requires photosensitizers which have both sufficient quantum yield for singlet oxygen generation and strong two photon absorption. Here we show that this can be achieved by conjugated linkage of zinc porphyrins to make dimers. We determined the quantum yield of generation of 1O2, φΔ , by measuring emission at 1270 nm using a near infra-red streak camera and found it to increase from 15% for a single porphyrin unit to 27 47% for the dimers with a conjugated linker. Then, we measured the spectra of two-photon absorption cross section, σ2, by a focus-tunable Z scan method, which allows for nondestructive investigation of light-sensitive materials. We observed a strong enhancement of the two photon absorption coefficient in the dimers, especially those with an alkyne linker. These results lead to an excellent figure of merit for two photon production of singlet oxygen (expressed by the product σ2xφΔ) in the porphyrin dimers, of around 3700 GM, which is very promising for applications involving treatment of deep tumors by photodynamic therapy.PostprintPeer reviewe

Enhanced two-photon absorption cross-sections of zinc(II) tetraphenylporphyrins peripherally substituted with d(6)-metal alkynyl complexes

International audienceThe syntheses of new Zn(II) tetraphenylporphyrin (ZnTPP) derivatives functionalized with electron-rich d6-transition metal alkynyl complexes at their periphery are reported. Z-scan measurements reveal remarkably large effective two-photon absorption (TPA) cross-sections in the visible range for these compounds