A Simple Exercise for Teaching Bacteriophage Concepts in the Undergraduate Laboratory Using Commercially Available Disinfectant.
Ontology highlight
ABSTRACT:
SUBMITTER: Khan LB
PROVIDER: S-EPMC6113933 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Bacteriophage are among the most diverse and numerous microbes inhabiting our planet. Yet many laboratory activities fail to engage students in meaningful exploration of their diversity, unique characteristics, and abundance. In this curriculum activity students use a standard plaque assay to enumerate bacteriophage particles from a natural sample and use the scientific method to address questions about host specificity and diversity. A raw primary sewage sample is enriched for bacteriophage using hosts in the family Enterobacteriaceae. Students hypothesize about host specificity and use quantitative data (serial dilution and plaque assay) to test their hypotheses. Combined class data also help them answer questions about phage diversity. The exercise was field tested with a class of 47 students using pre- and posttests. For all learning outcomes posttest scores were higher than pretest scores at or below p = 0.01. Average individualized learning gain (G) was also calculated for each learning outcome. Students' use of scientific language in reference to bacteriophage and host interaction significantly improved (p = 0.002; G = 0.50). Improved means of expression helped students construct better hypotheses on phage host specificity (G = 0.31, p = 0.01) and to explain the plaque assay method (G = 0.33, p = 0.002). At the end of the exercise students also demonstrated improved knowledge and understanding of phage specificity as related to phage therapy in humans (p < 0.001; G = 51).
| S-EPMC3706169 | biostudies-literature
Project description:Given the potential for human exposure to silver nanoparticles from spray disinfectants and dietary supplements, we characterized the silver-containing nanoparticles in 22 commercial products that advertised the use of silver or colloidal silver as the active ingredient. Characterization parameters included: total silver, fractionated silver (particulate and dissolved), primary particle size distribution, hydrodynamic diameter, particle number, and plasmon resonance absorbance. A high degree of variability between claimed and measured values for total silver was observed. Only 7 of the products showed total silver concentrations within 20% of their nominally reported values. In addition, significant variations in the relative percentages of particulate vs. soluble silver were also measured in many of these products reporting to be colloidal. Primary silver particle size distributions by transmission electron microscopy (TEM) showed two populations of particles - smaller particles (<5nm) and larger particles between 20 and 40nm. Hydrodynamic diameter measurements using nanoparticle tracking analysis (NTA) correlated well with TEM analysis for the larger particles. Z-average (Z-Avg) values measured using dynamic light scattering (DLS); however, were typically larger than both NTA or TEM particle diameters. Plasmon resonance absorbance signatures (peak absorbance at around 400nm indicative of metallic silver nanoparticles) were only noted in 4 of the 9 yellow-brown colored suspensions. Although the total silver concentrations were variable among products, ranging from 0.54mg/L to 960mg/L, silver containing nanoparticles were identified in all of the product suspensions by TEM.
| S-EPMC5939576 | biostudies-literature
Project description:The use of colloidal silver-containing products as dietary supplements, immune boosters and surface disinfectants has increased in recent years which has elevated the potential for human exposure to silver nanoparticles and ions. Product mislabeling and long-term use of these products may put consumers at risk for adverse health outcomes including argyria. This study assessed several physical and chemical characteristics of five commercial products as well as their cytotoxicity using a rat intestinal epithelial cell (IEC-6) model. Concentrations of silver were determined for both the soluble and particulate fractions of the products. Primary particle size distribution and elemental composition were determined by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. Hydrodynamic diameters were measured using nanoparticle tracking analysis (NTA) and dynamic light scattering (DLS). The effect of gastrointestinal (GI) simulation on the colloidal silver products was determined using two systems. First, physical and chemical changes of the silver nanoparticles in these products was assessed after exposure to Synthetic Stomach Fluid (SSF) resulting in particle agglomeration, and the appearance of AgCl on the surfaces and between particles. IEC-6 cells were exposed for 24 h to dilutions of the products and assessed for cell viability. The products were also treated with a three-stage simulated GI system (stomach and intestinal fluids) prior to exposure of the IEC-6 cells to the isolated silver nanoparticles. Cell viability was affected by each of the consumer products. Based on the silver nitrate and commercial silver nanoparticle dose response, the cytotoxicity for each of the colloidal silver products was attributed to the particulate silver, soluble silver or non?silver matrix constituents.
| S-EPMC7786200 | biostudies-literature
Project description:BACKGROUND: Residents-as-teachers (RATs) programs have been shown to improve trainees' teaching skills, yet these decline over time. INTERVENTION: We adapted a commercial Web-based system to maintain resident teaching skills through reflection and deliberate practice and assessed the system's ability to (1) prevent deterioration of resident teaching skills and (2) provide information to improve residents' teaching skills and teaching program quality. METHODS: Ten first-year obstetrics-gynecology (Ob-Gyn) residents participated in a RATs program. Following the program, they used a commercial evaluation system to complete self-assessments of their teaching encounters with medical students. Students also evaluated the residents. To assess the system's effectiveness, we compared these residents to historical controls with an Objective Structured Teaching Examination (OSTE) and analyzed the ratings and the free text comments of residents and students to explore teaching challenges and improve the RATs program. RESULTS: The intervention group outscored the control group on the OSTE (mean score ± SD = 81 ± 8 versus 74 ± 7; P = .05, using a 2-tailed Student t-test). Rating scale analysis showed resident self-assessments were consistently lower than student evaluations, with the difference reaching statistical significance in 3 of 6 skills (P < .05). Comments revealed that residents most valued using innovative teaching techniques, while students most valued a positive educational climate and interpersonal connections with residents. Recommended targets for RATs program improvement included teaching feedback, time-limited teaching, and modeling professionalism behaviors. CONCLUSIONS: Our novel electronic Web-based reinforcement system shows promise in preventing deterioration of resident teaching skills learned during an Ob-Gyn RATs program. The system also was effective in gaining resident and student insights to improve RATs programs. Because our intervention was built upon a commercially available program, our approach could prove useful to the large population of current subscribers.
| S-EPMC3312536 | biostudies-other
Project description:Laboratory science requires careful maintenance of sterile reagents and tools as well as the sterilization of waste prior to disposal. However, steam autoclaves typically used for this purpose may not be readily accessible to everyone in the scientific community, such as K-12 teachers, researchers in the field, students in under-funded laboratories, or persons in the developing world who lack funding and resources. This work examines the use of commercial electric pressure cookers as an alternative method for the sterilization of media, instruments, and waste. Four commonly available brands of pressure cooker were tested for their ability to sterilize microbiological media, a variety of metal instruments, and high-titer microbial cultures. All four pressure cookers were able to sterilize these starting materials as well as a range of microbial types, including Gram-positive bacteria, Gram-negative bacteria, filamentous fungi, unicellular fungi, and mixed environmental samples. Only the Instant Pot, however, was able to sterilize autoclave tester ampoules of Geobacillus stearothermophilus spores. These results suggest that, depending on the nature of the work undertaken, store-bought pressure cookers can be an appropriate substitute for commercial autoclaves. Their adoption may also help increase the accessibility of science to a broader range of investigators.
| S-EPMC6289433 | biostudies-literature
Project description:IntroductionCystic fibrosis (CF) is a high-yield undergraduate medical education topic that lends itself to adaptability of content. We used a CF case paired with activities to deliver content in a near-peer teaching session. First-year (M1) and second-year (M2) medical students contributed acquired knowledge of protein structure and obstructive lung disease, respectively, to generate a concept map and address discussion questions.MethodsCombined groups of M1 and M2 students reviewed a CF case and a concept map prompt. For 30 minutes, they created a concept map describing connections between molecular biology and clinical manifestations. We summarized by reviewing concept maps and discussion questions. The efficacy of the session was determined by comparing exam performance of class attenders and nonattenders (M2) and performance on questions related and unrelated to the exercise (M1). We also determined students' perception of the session and incorporation of additional core competencies.ResultsM2 students' performance was 3.8% higher (p = .296) and M1 students' performance was 1.8% higher (p = .286) than their respective controls. Students commented positively on the exercise and perceived more than one core competency as part of the session.DiscussionAlthough there was no significant improvement in exam performance, this curriculum used near-peer teaching to reinforce previously learned material and apply recently acquired material in an engaging format without detriment to either group. This method can be adapted to different learner groups and provides an opportunity to deliver and assess other core medical competencies.
| S-EPMC7453652 | biostudies-literature
Project description:The mitochondrial energy score (MES) protocol, developed by the Myhill group, is marketed as a diagnostic test for chronic fatigue syndrome/Myalgic Encephalomyelitis (CFS/ME). This study assessed the reliability and reproducibility of the test, currently provided by private clinics, to assess its potential to be developed as an NHS accredited laboratory test. We replicated the MES protocol using neutrophils and peripheral blood mononuclear cells (PBMCs) from CFS/ME patients (10) and healthy controls (13). The protocol was then repeated in PBMCs and neutrophils from healthy controls to investigate the effect of delayed sample processing time used by the Myhill group. Experiments using the established protocol showed no differences between CFS/ME patients and healthy controls in any of the components of the MES (p???0.059). Delaying blood sample processing by 24?hours (well within the 72?hour time frame quoted by the Myhill group) significantly altered many of the parameters used to calculate the MES in both neutrophils and PBMCs. The MES test does not have the reliability and reproducibility required of a diagnostic test and therefore should not currently be offered as a diagnostic test for CFS/ME. The differences observed by the Myhill group may be down to differences in sample processing time between cohorts.
| S-EPMC6686017 | biostudies-literature
Project description: Not available
| S-EPMC7176053 | biostudies-literature
Project description:Changing consumer attitudes show an increased interest in non-chemical antimicrobials in food preservation and safety. This greater interest of consumers in more 'natural' or 'clean-label' food interventions is complicated by concurrent demands for minimally processed, ready-to-eat (RTE) foods with long shelf lives. Two viable interventions are bacteriophage (phage) and bacteriocins, a number of which have already been approved for use in food safety. Listeriosis is a serious foodborne infection which affects at-risk members of the population. Listeriosis incidence has increased between 2008 and 2015 and has a case fatality rate of up to 20% with antibiotic intervention. Here, we tested an intervention to attempt to control a pathogenic Listeria monocytogenes strain in a food model using two of these alternative antimicrobials. Phage P100 on its own had a significant effect on L. monocytogenes ScottA numbers in coleslaw over a 10-day period at 4 °C (p ≤ 0.001). A combination of P100 and Nisaplin® (a commercial formulation of the lantibiotic bacteriocin, nisin) had a significant effect on the pathogen (p ≤ 0.001). P100 and Nisaplin® in combination were more effective than Nisaplin® alone, but not P100 alone.
| S-EPMC6893746 | biostudies-literature
Project description:Zika virus (ZIKV) infection during pregnancy can cause adverse fetal outcomes and severe irreversible congenital birth defects including microcephaly. Immunohistochemistry (IHC) is a valuable diagnostic tool for detecting ZIKV antigens in tissues from cases of fetal loss in women infected with ZIKV, and for providing insights into disease pathogenesis. As a result, there is increasing demand for commercially available ZIKV antibodies for use in IHC assays. ZIKV antibodies were selected and obtained from commercial sources to include both mouse and rabbit hosts, and a variety of antigenic targets. Pretreatment conditions and antibody concentrations resulting in optimal immunohistochemical staining were determined using ZIKV cell control and polymerase chain reaction (PCR)-confirmed ZIKV case control material (fetal brain tissue). Cross-reactivity of the antibodies against other flaviviruses (dengue virus serogroups 1-4, yellow fever virus, Japanese encephalitis virus, West Nile virus) and chikungunya virus was also evaluated. Immunostaining using the commercially available antibodies was compared to a previously validated ZIKV IHC assay used for primary diagnosis. Four antibodies demonstrated optimal staining similar to the previously validated ZIKV IHC assay. Two of the four antibodies cross-reacted with dengue virus, while the other two antibodies showed no cross-reactivity with dengue, other flaviviruses, or chikungunya virus. Differences in the cross-reactivity profiles could not be entirely explained by the antigenic target. Commercially available ZIKV antibodies can be optimized for use in IHC testing to aid in ZIKV diagnostic testing and an evaluation of tissue tropism.
| S-EPMC5783976 | biostudies-literature