Excet (United States)

Synthetic biology and genome engineering capabilities have facilitated the utilization of bacteria for myriad of applications ranging from medical treatments to biomanufacturing of complex molecules. The bacterial outer membrane, specifically the lipopolysaccharide (LPS), plays an integral role in the physiology, pathogenesis, and serves as a main target of existing detection assays for Gram-negative bacteria. Here we use CRISPR/Cas9 recombineering to insert Yersinia pestis lipid A biosynthesis genes into the genome of an Escherichia coli strain expressing the lipid IVa subunit. We successfully inserted three genes: kdsD, lpxM, and lpxP into the E. coli genome and demonstrated their expression via reverse transcription PCR (RT-PCR). Despite observing expression of these genes, analytical characterization of the engineered strain’s lipid A structure via MALDI-TOF mass spectrometry indicated that the Y. pestis lipid A was not recapitulated in the E. coli background. As synthetic biology and genome engineering technologies advance, novel applications and utilities for the detection and treatments of dangerous pathogens like Yersinia pestis will continue to be developed.

Detection canines serve critical roles to support the military, homeland security and border protection. Some explosive detection tasks are physically demanding for dogs, and prior research suggests this can lead to a reduction in olfactory detection sensitivity. To further evaluate the effect of exercise intensity on olfactory sensitivity, we developed a novel olfactory paradigm that allowed us to measure olfactory detection thresholds while dogs exercised on a treadmill at two different exercise intensities. Dogs (n = 3) showed a decrement in olfactory detection for 1-bromooctane at 10-3 (v/v) dilutions and lower under greater exercise intensity. Dogs' hit rate for the lowest concentration dropped from 0.87 ± 0.04 when walking at low intensity to below 0.45 ± 0.06 when trotting at moderate intensity. This decline had an interaction with the duration of the session in moderate intensity exercise, whereby dogs performed near 100% detection in the first 10 min of the 8 km/h session, but showed 0% detection after 20 min. Hit rates for high odor concentrations (10-2) were relatively stable at both low (1 ± 0.00) and moderate (0.91 ± 0.04) exercise intensities. The paradigm and apparatus developed here may be useful to help further understand causes of operationally relevant olfactory detection threshold decline in dogs.

Sulfur mustard (HD) poses a serious threat due to its relatively simple production process. Exposure to HD in the short-term causes an inflammatory response, while long-term exposure results in DNA and RNA damage. Respiratory tract tissue models were exposed to relatively low concentrations of HD and collected at 3 and 24 h post exposure. Histology, cytokine ELISAs, and mass spectrometric-based analyses were performed. Histology and ELISA data confirmed previously seen lung damage and inflammatory markers from HD exposure. The multi-omic mass spectrometry data showed variation in proteins and metabolites associated with increased inflammation, as well as DNA and RNA damage. HD exposure causes DNA and RNA damage that results in variation of proteins and metabolites that are associated with transcription, translation and cellular energy.

Abstract Stony coral tissue loss disease (SCTLD) remains an unprecedented epizootic disease, representing a substantial threat to the persistence and health of coral reef ecosystems in the Tropical Western Atlantic since its first observation near Miami, Florida in 2014. In addition to transport between adjacent reefs indicative of a waterborne pathogen(s) dispersing on ocean currents, it has spread throughout the Caribbean to geographically- and oceanographically-isolated reefs, in a manner suggestive of ship and ballast water transmission. Here we evaluate the potential for waterborne transmission of SCTLD including via simulated ballast water, and test the efficacy of commonly-used UV radiation treatment of ballast water. Two species of reef-building corals (Orbicella faveolata and Pseudodiploria strigosa) were subjected to 1) disease-exposed or UV-treated disease-exposed water, and 2) a ballast hold time series of disease-exposed water in two carefully-controlled experiments to evaluate transmission. Our experiments demonstrated transmission of SCTLD through water, rather than direct contact between diseased and healthy corals. While UV treatment of disease-exposed water led to a 50% reduction in the number of corals exhibiting disease signs in both species, the statistical risk of transmission and volume of water needed to elicit SCTLD lesions remained similar to untreated disease-exposed water. The ballast hold time (24 h versus 120 h) did not have a significant effect on the onset of visible disease signs for either species, though there appeared to be some evidence of a concentration effect for P. strigosa as lesions were only observed after the 120 h ballast hold time. Results from both experiments suggest that the SCTLD pathogens can persist in both untreated and UV-treated ballast water and remain pathogenic. Ballast water may indeed pose a threat to the continued spread and persistence of SCTLD, warranting further investigation of additional ballast water treatments and pathogen detection methods.

Anode free lithium metal cells provide a pathway towards higher energy density cells relevant for the increasing demands of applications ranging from portable electronics to electrified transportation. This work demonstrates the application of a thermal gradient between an anode-free copper substrate and a LiFePO4 positive electrode to enable longer cycle life when compared to anode-free cells cycled at 20 °C. Specifically, cycling cells with the negative and positive electrodes held at 6.7 and 6 °C, respectively, is hypothesized to result in a more uniform, densely packed initial deposition of Li-metal. Beyond extended cycle life, cells cycled using this approach demonstrate slower initial capacity fade at higher C-rates (>1C) compared to their ambient temperature counterparts. This presentation will address cell performance when using concentrated electrolytes, varied substrates for the anode-free negative electrode, as well as pouch formats with an applied stack pressure. Taken as a collective, these results can be used to motivate thermal gradients across the electrode as an effective formation strategy, balancing performance improvements with practicality of implementation.

Bio-Layer Interferometry (BLI) enables the detection and characterization of molecular interactions in real-time without the hassle and interference of labeling. The affinity constant (KD) obtained in the BLI analysis is an excellent indicator of quality of biomolecules such as antibodies, aptamers, peptides, etc. This method was used to analyze a peptide macrocycle against the Abrax protein, but can be used for any peptide macrocycle/analyte system.

O rio Araguari hospeda atualmente 3 empreendimentos hidreletricos em seu curso principal e o empreendimento localizado mais a jusante causou, durante seus testes de operacao, a mortalidade de muito especimes de peixes de forma continua e repetida. Para descobrir a causa da morte desses peixes foi realizado um estudo pontual em outubro de 2014 onde foram analisados varios exemplares de peixes mortos e analisadas uma serie de dados ambientais. Todas as possiveis causas da referida mortalidade foram descartadas devido aos dados recolhidos, exceto a supersaturacao de oxigenio na agua causada pela acao conjunta do funcionamento das turbinas e do represamento desta agua pela acao da mare.

Accurate pathogen detection and diagnosis is paramount in clinical success of treating patients. There are two general paradigms in pathogen detection: molecular and immuno-based, and phage-based detection is a third emerging paradigm due to its sensitivity and selectivity. Molecular detection methods look for genetic material specific for a given pathogen in a sample usually by polymerase chain reaction (PCR). Immuno-methods look at the pathogen components (antigens) by antibodies raised against that pathogen specific antigens. There are different variations and products based on these two paradigms with advantages and disadvantages. The third paradigm at least for bacterial pathogen detection entails bacteriophages specific for a given bacterium. Sensitivity and specificity are the two key parameters in any pathogen detection system. By their very nature, bacteriophages afford the best sensitivity for bacterial detection. Bacteria and bacteriophages form the predator-prey pair in the evolutionary arms race and has coevolved over time to acquire the exquisite specificity of the pair, in some instances at the strain level. This specificity has been exploited for diagnostic purposes of various pathogens of concern in clinical and other settings. Many recent reviews focus on phage-based detection and sensor technologies. In this review, we focus on a very special group of pathogens that are of concern in biodefense because of their potential misuse in bioterrorism and their extremely virulent nature and as such fall under the Centers for Disease and Prevention (CDC) Category A pathogen list. We describe the currently available phage methods that are based on the usual modalities of detection from culture, to molecular and immuno- and fluorescent methods. We further highlight the gaps and the needs for more modern technologies and sensors drawing from technologies existing for detection and surveillance of other pathogens of clinical relevance.

Acoustic metasurfaces are ultrathin (subwavelength thickness) structures that can demonstrate extreme acoustic properties, such as negative or near-zero values, similar to those seen in acoustic metamaterials. The negligibly small thickness of acoustic metasurfaces make them a more practical alternative to metamaterials for certain applications. In this work, we experimentally demonstrate an aqueous acoustic metamaterial that employs subwavelength, flexural elements that acoustically act in parallel to achieve enhanced acoustic transmission and broadband negative effective density. The metasurface was constructed from a brass plate, which was machined to have a parallel arrangement of circular, flexural elements on the surface, and experimentally tested in water over the nominal range of 50–100 kHz. The reflected and transmitted acoustic data were compared between a brass plate with and without the circular flexural elements. It was observed that the aqueous acoustic metasurface made from a brass plate with circular flexural elements showed improved broadband transmission. A detailed description of the experimental testing and analysis will be discussed. [Work supported by the Office of Naval Research]