Using Antenna Tile-Assisted Substrate Delivery to Improve Detection Limits of Deoxyribozyme

One common limitation of enzymatic reactions is the diffusion of a substrate to the enzyme active site and/or the release of the reaction products. These reactions are known as diffusion –controlled. Overcoming this limitation may enable faster catalytic rates, which in the case of catalytic biosensors can potentially lower limits of detection of specific analyte. Here we created an artificial system to enable deoxyribozyme (Dz) 10-23 based biosensor to overcome its diffusion limit. The sensor consists of the two probe strands, which bind to the analyzed nucleic acid by Watson-Crick base pairs and, upon binding re-form the catalytic core of Dz 10-23. The activated Dz 10-23 cleaves the fluorophore and quencher-labeled DNA-RNA substrate which separates the fluorophore from the quencher thus producing high fluorescent signal. This system uses a Dz 10-23 biosensor strand associated to a DNA antenna tile, which captures the fluorogenic substrate and channels it to the reaction center where the Dz 10-23 cleaves the substrate. DNA antenna tile captures fluorogenic substrate and delivers it to the activated Dz 10-23 core. This allows for lower levels of analyte to be detected without compromising the specificity of the biosensor. The results of this experiment demonstrated that using DNA antenna, we can create a synthetic environment around the Dz 10-23 biosensor to increase its efficiency and allow for lower levels of analyte to be detected without using amplification techniques like PCR

Vaginal Microbicide Preferences Among Midwestern Urban Adolescent Women

Purpose The purpose of this study was to assess adolescent women's preferences for specific microbicide characteristics including pregnancy prevention, timing of application, potential for side effects, and whether it targeted human immunodeficiency virus (HIV) or other sexually transmitted infections (STI). Potential differences in microbicide preferences by adolescent age group and behavioral patterns including engaging in sexual intercourse and use of hormonal contraception were examined, as it was hypothesized that as adolescents progress into adulthood and gain sexual experience their preferences in microbicide characteristics may shift. Method Adolescent and young women (N = 405, 56.0% African American; 24.0% Euro-American) between the ages of 14 and 20 (mean = 17.0, SD = 1.8) were recruited from urban community-based clinics. Video-Audio Computer-Assisted Self-Interviews were conducted with the young women, during which they were asked about their preferences regarding the characteristics of hypothetical vaginal microbicides. Conjoint analysis was utilized to determine adolescent women's relative preferences for each microbicide characteristic and intent-to-purchase microbicides based upon a combination of the selected properties. Results Overall, the results suggest adolescent and young women had an ordered preference for a microbicide with (1) no side effects, (2) pregnancy prevention, (3) postcoital application, and (4) protection against HIV. Age and behavioral group conjoint analyses resulted in the same pattern of preferences as those reported for the entire group. However, women having sex and not using hormonal contraception had a stronger preference for postcoital application. Conclusion The findings suggest that young women's ratings of microbicides were sensitive to characteristics such as side effects, pregnancy prevention, and timing of application and should be considered in microbicide development. The conjoint analysis approach is useful in understanding microbicide preferences, and should be utilized with other populations to assess preferences for specific microbicide characteristics

Community Structure in Congressional Cosponsorship Networks

We study the United States Congress by constructing networks between Members of Congress based on the legislation that they cosponsor. Using the concept of modularity, we identify the community structure of Congressmen, as connected via sponsorship/cosponsorship of the same legislation, to investigate the collaborative communities of legislators in both chambers of Congress. This analysis yields an explicit and conceptually clear measure of political polarization, demonstrating a sharp increase in partisan polarization which preceded and then culminated in the 104th Congress (1995-1996), when Republicans took control of both chambers. Although polarization has since waned in the U.S. Senate, it remains at historically high levels in the House of Representatives.Comment: 8 pages, 4 figures (some with multiple parts), to appear in Physica A; additional background info and explanations added from last versio

The Post-Exercise Inflammatory Response to Repeated-Sprint Running in Hypoxia

This study investigated the acute inflammatory response to a repeat-sprint training session in hypoxia. Eleven amateur team-sport athletes completed a repeat-sprint training in hypoxia (RSH) protocol (4 sets of 4x4-s running sprints) in both normoxia and normobaric hypoxia (FiO2 0.145 to simulate an altitude of 3000 m) on separate days. Participants provided venous blood samples prior to (PRE), immediately after (POST), and 3 h after (3 h) completion of the protocol, and capillary blood lactate samples were taken upon arrival, at PRE, and at POST. Distance was recorded for each sprint. Venous blood samples were analysed to determine plasma concentrations of cytokines IL-1β, IL-1ra, IL-6, IL-8, IL-10, and TNFα. There was no interaction or main effect of condition for any cytokine (p > 0.05). However, time effects indicated that IL-10 was decreased by an average of 19% across the two experimental trials at 3 h compared to POST (p = 0.04), IL-6 increased by 55% from PRE to POST (p = 0.03) then decreased by 43% from POST to 3 h (p = 0.02), and IL-8 decreased by 30% from PRE to POST (p = 0.04) and was further reduced at 3 h compared to POST (by an additional 23%; p = 0.02). A time × condition interaction (p = 0.03) indicated that lactate was higher in hypoxia. There was no interaction effect or effect of condition for sprint distance (p > 0.05). These results suggest that team-sport athletes can perform a RSH session without increasing inflammation when compared to the same training session performed in normoxia

Immunomodulatory effects of fucoidan in recreationally active adult males undertaking 3-weeks of intensified training

The aim of the current study was to determine whether daily fucoidan supplementation ( Undaria pinnatifida extract containing &gt;85% fucoidan, 1 g/day) for three-weeks in a double blind-placebo controlled cross-over trial (ACTRN12621000872831) could modulate alterations in faecal (calprotectin, lysozyme and IgA) and salivary (lactoferrin, lysozyme and IgA) markers of mucosal immune competence typically observed in response to both acute physical activity, and a period of intensified exercise training, in healthy recreationally active men ( n  = 12). Participants responded positively to the intensified training with 16-19% improvement in mean power that was not different between supplement groups. Faecal biomarkers and concentrations of lactoferrin, lysozyme and IgA from resting saliva samples were largely stable over the supplementation period. Concentrations of salivary biomarkers varied significantly over time in response to acute exercise, however differences between supplementation groups were modest. For salivary lysozyme, there was a trend for a lower magnitude of increase post-exercise ( p  = 0.08) and limited return towards pre-exercise in response to fucoidan. For salivary IgA, a greater acute exercise response was noted for IgA in response to fucoidan (~2.7-fold higher; p  = 0.02). Different dosage and supplementation protocols and inclusion of additional immune markers should be considered in subsequent assessments of any potential benefits of fucoidan supplementation in healthy active adults. </p

Association between Landscape Factors and Spatial Patterns of Plasmodium knowlesi Infections in Sabah, Malaysia.

The zoonotic malaria species Plasmodium knowlesi has become the main cause of human malaria in Malaysian Borneo. Deforestation and associated environmental and population changes have been hypothesized as main drivers of this apparent emergence. We gathered village-level data for P. knowlesi incidence for the districts of Kudat and Kota Marudu in Sabah state, Malaysia, for 2008-2012. We adjusted malaria records from routine reporting systems to reflect the diagnostic uncertainty of microscopy for P. knowlesi. We also developed negative binomial spatial autoregressive models to assess potential associations between P. knowlesi incidence and environmental variables derived from satellite-based remote-sensing data. Marked spatial heterogeneity in P. knowlesi incidence was observed, and village-level numbers of P. knowlesi cases were positively associated with forest cover and historical forest loss in surrounding areas. These results suggest the likelihood that deforestation and associated environmental changes are key drivers in P. knowlesi transmission in these areas

HI in four star-forming low-luminosity E/S0 and S0 galaxies

We present HI data cubes of four low-luminosity early-type galaxies which are currently forming stars. These galaxies have absolute magnitudes in the range M_B=-17.9 to -19.9 (H_o=50 km/s/Mpc). Their HI masses range between a few times 10^8 and a few times 10^9 M_sun and the corresponding values for M_HI/L_B are between 0.07 and 0.42, so these systems are HI rich for their morphological type. In all four galaxies, the HI is strongly centrally concentrated with high central HI surface densities, in contrast to what is typically observed in more luminous early-type galaxies. In two galaxies (NGC 802 and ESO 118-G34), the kinematics of the HI suggests that the gas is in a strongly warped disk, which we take as evidence for recent accretion of HI. In the other two galaxies (NGC 2328 and ESO 027-G21) the HI must have been part of the systems for a considerable time. The HI properties of low-luminosity early-type galaxies appear to be systematically different from those of many more luminous early-type galaxies, and we suggest that these differences are due to a different evolution of the two classes. The star formation history of these galaxies remains unclear. Their UBV colours and Halpha emission-line strengths are consistent with having formed stars at a slowly-declining rate for most of the past 10^10 years. However, the current data do not rule out a small burst of recent star formation overlaid on an older stellar population.Comment: To appear in AJ, LateX, figures in gif format, paper also available at http://www.nfra.nl/~morganti/LowLu

Piezo1 Forms Specific, Functionally Important Interactions with Phosphoinositides and Cholesterol

Touch, hearing, and blood pressure regulation require mechanically gated ion channels that convert mechanical stimuli into electrical currents. One such channel is Piezo1, which plays a key role in the transduction of mechanical stimuli in humans and is implicated in diseases, such as xerocytosis and lymphatic dysplasia. There is building evidence that suggests Piezo1 can be regulated by the membrane environment, with the activity of the channel determined by the local concentration of lipids, such as cholesterol and phosphoinositides. To better understand the interaction of Piezo1 with its environment, we conduct simulations of the protein in a complex mammalian bilayer containing more than 60 different lipid types together with electrophysiology and mutagenesis experiments. We find that the protein alters its local membrane composition, enriching specific lipids and forming essential binding sites for phosphoinositides and cholesterol that are functionally relevant and often related to Piezo1-mediated pathologies. We also identify a number of key structural connections between the propeller and pore domains located close to lipid-binding sites

Re-sensitization of Mycobacterium smegmatis to Rifampicin Using CRISPR Interference Demonstrates Its Utility for the Study of Non-essential Drug Resistance Traits

© 2021 Faulkner, Cox, Goh, van Bohemen, Gibson, Liebster, Wren, Willcocks and Kendall. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). https://creativecommons.org/licenses/by/4.0/A greater understanding of the genes involved in antibiotic resistance in Mycobacterium tuberculosis (Mtb) is necessary for the design of improved therapies. Clustered regularly interspaced short palindromic repeat interference (CRISPRi) has been previously utilized in mycobacteria to identify novel drug targets by the demonstration of gene essentiality. The work presented here shows that it can also be usefully applied to the study of non-essential genes involved in antibiotic resistance. The expression of an ADP-ribosyltransferase (Arr) involved in rifampicin resistance in Mycobacterium smegmatis was silenced using CRISPRi and the impact on rifampicin susceptibility was measured. Gene silencing resulted in a decrease in the minimum inhibitory concentration (MIC) similar to that previously reported in an arr deletion mutant. There is contradictory evidence for the toxicity of Streptococcus pyogenes dCas9 (dCas9 Spy) in the literature. In this study the expression of dCas9 Spy in M. smegmatis showed no impact on viability. Silencing was achieved with concentrations of the aTc inducer lower than previously described and with shorter induction times. Finally, designing small guide RNAs (sgRNAs) that target transcription initiation, or the early stages of elongation had the most impact on rifampicin susceptibility. This study demonstrates that CRISPRi based gene silencing can be as impactful as gene deletion for the study of non-essential genes and further contributes to the knowledge on the design and induction of sgRNAs for CRISPRi. This approach can be applied to other non-essential antimicrobial resistance genes such as drug efflux pumps.Peer reviewe