A Process for Preparing High Graphene Sheet Content Carbon Materials from Biochar Materials

Graphene is monolayer graphite and has higher electron mobility than silicon, high heat conduction, and special optical properties. In this study, we have attempted to use a two-step process (an acid pretreatment followed by a heat treatment) for producing high graphene sheet content (>80%) carbon materials (GSCCMs) from monocotyledonous and dicotyledonous biochar materials prepared at 350°C. The highest graphene sheet content of 83.86% is found with the CH3COOH pretreatment followed by a 1500°C heat treatment of monocotyledonous biochar materials, and its conductivity was measured at 84.69 S/cm. Therefore, preparing GSCCMs from biochar materials could highly reduce the cost

Identification and characterization of the genetic determinants for yellow fever virus infection and dissemination in Aedes aegypti

Doctor of PhilosophyDepartment of Diagnostic Medicine/PathobiologyStephen HiggsThe genetic composition of arboviruses is a critical determinant of viral infectivity and the capacity for virus dissemination in arthropod vectors. Due to concerns related to a hypothetical potential for loss of attenuation, the supression of vector infection and dissemination is a critical component for the rationale-based design of live-attenuated flavivirus vaccine candidates. The yellow fever virus (YFV) 17D vaccine virus is not only attenuated in vertebrates, but also has low infectivity for Aedes agypti mosquitoes and since it does not disseminate, it is not transmissible. Using a reverse genetics system, the mutations present in the envelope protein YFV 17D virus were characterized in Ae. aegypti to determine the role of mutations in limiting the viral infectivity and dissemination capacity. This knowledge would contribute to the rational design of live attenuated vaccines with the desirable phenotype of being nontransmissible by arthropod vectors. The upper lateral portion of the YFV 17D envelope (E) protein domain III (EDIII) habors the T380R mutation in the FG loop. Experiments demonstrated that the T380R mutation was associated with the viral infectivity phenotype for mosquitoes, but did not influence dissemination into the secondary tissues. The G52R mutation in the molecular hinge region that is located between E protein domains I (EDI) and II, significantly reduced viral infectivity for mosquitoes. In contrast, when cloned into the Asibi wildtype virus genetic backbone, the T173I mutation in the loop structure between the G0 and H0 β- strands did not attenuate viral infection and dissemination. The double mutant virus containing both the G52R and T173I mutations in the E protein, showed a similar attenuated reduced infectivity to the single G52R mutant. The M299I mutation in the linker region between EDI and EDIII resulted in a significantly lower viral infectivity at the initial phase of viral infection at 7 days post-infection in Ae. aegypti. In conclusion, the characterization on four mutations in the YFV 17D vaccine E protein have demonstrated three genetic loci, that can influence the process of YFV infection in Ae. aegypti. These results provide new knowledge and understanding which may have broad applications for the rationale design of safe flavivirus vaccines, via targeting genetic loci and introducing specific mutations that preclude infection of, and transmission by arthropod vectors

Biological Control Strategies for Mosquito Vectors of Arboviruses

Citation: Huang, Y.-J.S.; Higgs, S.; Vanlandingham, D.L. Biological Control Strategies for Mosquito Vectors of Arboviruses. Insects 2017, 8, 21.Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses

Culex tarsalis is a competent vector species for Cache Valley virus

Background: Cache Valley virus (CVV) is a mosquito-borne orthobunyavirus endemic in North America. The virus is an important agricultural pathogen leading to abortion and embryonic lethality in ruminant species, especially sheep. The importance of CVV in human public health has recently increased because of the report of severe neurotropic diseases. However, mosquito species responsible for transmission of the virus to humans remain to be determined. In this study, vector competence of three Culex species mosquitoes of public health importance, Culex pipiens, Cx. tarsalis and Cx. quinquefasciatus, was determined in order to identify potential bridge vector species responsible for the transmission of CVV from viremic vertebrate hosts to humans. Results: Variation of susceptibility to CVV was observed among selected Culex species mosquitoes tested in this study. Per os infection resulted in the establishment of infection and dissemination in Culex tarsalis, whereas Cx. pipiens and Cx. quinquefasciatus were highly refractory to CVV. Detection of viral RNA in saliva collected from infected Cx. tarsalis provided evidence supporting its role as a competent vector. Conclusions: Our study provided further understanding of the transmission cycles of CVV and identifies Cx. tarsalis as a competent vector

Flavivirus-Mosquito Interactions

Citation: Huang, Y.-J.S.; Higgs, S.; Horne, K.M.; Vanlandingham, D.L. Flavivirus-Mosquito Interactions. Viruses 2014, 6, 4703-4730.The Flavivirus genus is in the family Flaviviridae and is comprised of more than 70 viruses. These viruses have a broad geographic range, circulating on every continent except Antarctica. Mosquito-borne flaviviruses, such as yellow fever virus, dengue virus serotypes 1–4, Japanese encephalitis virus, and West Nile virus are responsible for significant human morbidity and mortality in affected regions. This review focuses on what is known about flavivirus-mosquito interactions and presents key data collected from the field and laboratory-based molecular and ultrastructural evaluations

Simple scheme for expanding a polarization-entangled W state by adding one photon

We propose a simple scheme for expanding a polarization-entangled W state. By mixing a single photon and one of the photons in an n-photon W state at a polarization-dependent beam splitter (PDBS), we can obtain an (n+1)-photon W state after post-selection. Our scheme also opens the door for generating n-photon W states using single photons and linear optics.Comment: 3 pages, 2 figure

Infection and transmission of Cache Valley virus by Aedes albopictus and Aedes aegypti mosquitoes

Background: Cache Valley virus (CVV; Bunyavirales, Peribunyaviridae) is a mosquito-borne arbovirus endemic in North America. Although severe diseases are mainly observed in pregnant ruminants, CVV has also been recognized as a zoonotic pathogen that can cause fatal encephalitis in humans. Human exposures to CVV and its related subtypes occur frequently under different ecological conditions in the New World; however, neurotropic disease is rarely reported. High prevalence rates of neutralizing antibodies have been detected among residents in several Latin American cities. However, zoophilic mosquito species involved in the enzootic transmission are unlikely to be responsible for the transmission leading to human exposures to CVV. Mechanisms that lead to frequent human exposures to CVV remain largely unknown. In this study, competence of two anthropophilic mosquitoes, Aedes albopictus and Ae. aegypti, for CVV was determined using per os infection to determine if these species could play a role in the transmission of CVV in the domestic and peridomestic settings of urban and suburban areas. Results: Aedes albopictus were highly susceptible to CVV whereas infection of Ae. aegypti occurred at a significantly lower frequency. Whilst the dissemination rates of CVV were comparable in the two species, the relatively long period to attain maximal infectious titer in Ae. aegypti demonstrated a significant difference in the replication kinetics of CVV in these species. Detection of viral RNA in saliva suggests that both Ae. albopictus and Ae. aegypti are competent vectors for CVV under laboratory conditions. Conclusions: Differential susceptibility to CVV was observed in Ae. albopictus and Ae. aegypti, reflecting their relatively different capacities for vectoring CVV in nature. The high susceptibility of Ae. albopictus to CVV observed in this study suggests its potential role as an efficient vector for CVV. Complemented by the reports of multiple CVV isolates derived from Ae. albopictus, our finding provides the basis for how the dispersal of Ae. albopictus across the New World may have a significant impact on the transmission and ecology of CVV

Replication kinetics of a candidate live-attenuated vaccine for Cache Valley virus in Aedes albopictus

Background: The emergence or re-emergence of several orthobunyaviruses (order: Bunyavirales; family: Peribunyaviridae), including Cache Valley virus (CVV) and Oropouche virus, warrants the development and evaluation of candidate live-attenuated vaccines (LAVs). Ideally, these vaccines would elicit long-lasting immunity with one single immunization. Materials and Methods: Since the deletion of two virulence factors, NSs and NSm, has been shown to attenuate the virulence phenotype of orthobunyaviruses, phleboviruses, and nairoviruses, genetic manipulation of the viral genome is considered an effective strategy for the rational design of candidate LAVs for bunyaviruses across multiple families. In addition, the deletion of Rift Valley fever virus NSs and NSm genes has been shown to reduce transmission by mosquitoes. Results: In this study, the ability of a CVV mutant lacking the NSs and NSm genes (2delCVV) to replicate in intrathoracically injected Aedes albopictus was compared with the parental wild-type CVV (wtCVV) 6V633 strain. In contrast to the robust replication of wtCVV in injected mosquitoes, the multiplication kinetics of the 2delCVV mutant was reduced by more than a 100-fold. Conclusion: These results suggest that the deletion of NSm and NSs genes is a feasible approach to rationally design candidate orthobunyavirus LAVs that are highly attenuated in mosquitoes and, therefore, pose little risk of reversion to virulence and transmission

Immunogenicity of a candidate live attenuated vaccine for Rift Valley fever virus with a two-segmented genome

Rift Valley fever virus (RVFV) is an emerging arbovirus that affects both ruminants and humans. RVFV causes severe and recurrent outbreaks in Africa and the Arabian Peninsula with a significant risk for emergence into new locations. Although there are a variety of RVFV veterinary vaccines for use in endemic areas, there is currently no licensed vaccine for human use; therefore, there is a need to develop and assess new vaccines. Herein, we report a live-attenuated recombinant vaccine candidate for RVFV, based on the previously described genomic reconfiguration of the conditionally licensed MP12 vaccine. There are two general strategies used to develop live-attenuated RVFV vaccines, one being serial passage of wild-type RVFV strains to select attenuated mutants such as Smithburn, Clone 13, and MP12 vaccine strains. The second strategy has utilized reverse genetics to attenuate RVFV strains by introducing deletions or insertions within the viral genome. The novel candidate vaccine characterized in this report contains a two-segmented genome that lacks the medium viral segment (M) and two virulence genes (nonstructural small and nonstructural medium). The vaccine candidate, named r2segMP12, was evaluated for the production of neutralizing antibodies to RVFV in outbred CD-1 mice. The immune response induced by the r2segMP12 vaccine candidate was directly compared to the immune response induced by the rMP12 parental strain vaccine. Our study demonstrated that a single immunization with the r2segMP12 vaccine candidate at 105 plaque-forming units elicited a higher neutralizing antibody response than the rMP12 vaccine at the same vaccination titer without the need for a booster