Scanning Electron Microscopy Laboratory Portfolio

These images were prepared as part of the class MCR 484 Scanning Electron Microscopy at SUNY College of Environmental Science and Forestry, Fall 2016. All images were acquired on the JEOL JSM 5800 LV Scanning Electron Microscope in the N. C. Brown Center for Ultrastructure Studies

Session C, 2015 First Place: Polyphemus pediculus Survivorship in Insect Repellent Treated Water

At Cranberry Lake, one of the most commonly used topical products is insect repellant. Insect repellents are manufactured with varying percentages of DEET, or no DEET at all. DEET is a synthetic chemical consisting of organic compounds originally intended for jungle warfare. Trace amounts of DEET are found in local waterways throughout the summer, when swimming is a popular activity. This study focuses on Polyphemus pediculus, a zooplankton at the bottom of the aquatic food chain. Polyphemus pediculus is abundant in Cranberry Lake and is an indicator for health and functionality of the lake ecosystem. Three insect repellents containing varying percentages of DEET and two DEET-free repellents were tested on Polyphemus pediculus at high (6µL), medium (4µL), and low (2µL) amounts. The survivorship of zooplankton was observed over 30 minutes. It was found that insect repellants containing higher percentages of DEET killed Polyphemus faster than those containing lower percentages of DEET. It was also found that one DEET-free insect repellant killed the zooplankton at an equal rate, while the other killed them at a slower rate. Larger amounts of insect repellent in the water also killed Polyphemus faster. All insect repellents used in the experiment had adverse effects on survivorship on zooplankton, which should be taken into consideration before entering waterways. It can be concluded that insect repellant, even in trace amounts, can be detrimental to aquatic systems

A Dual-Tropic Primary HIV-1 Isolate That Uses Fusin and the β-Chemokine Receptors CKR-5, CKR-3, and CKR-2b as Fusion Cofactors

AbstractHere, we show that the β-chemokine receptor CKR-5 serves as a cofactor for M-tropic HIV viruses. Expression of CKR-5 with CD4 enables nonpermissive cells to form syncytia with cells expressing M-tropic, but not T-tropic, HIV-1 env proteins. Expression of CKR-5 and CD4 enables entry of a M-tropic, but not a T-tropic, virus strain. A dual-tropic primary HIV-1 isolate (89.6) utilizes both Fusin and CKR-5 as entry cofactors. Cells expressing the 89.6 env protein form syncytia with QT6 cells expressing CD4 and either Fusin or CKR-5. The β-chemokine receptors CKR-3 and CKR-2b support HIV-1 89.6 env-mediated syncytia formation but do not support fusion by any of the T-tropic or M-tropic strains tested. Our results suggest that the T-tropic viruses characteristic of disease progression may evolve from purely M-tropic viruses prevalent early in virus infection through changes in the env protein that enable the virus to use multiple entry cofactors

Afscheid van de klassieke procedure? Een verslag van een afscheid en een weerzien

Criminal Justice: Legitimacy, accountability, and effectivit

Clustered Mutations in HIV-1 Gag Are Consistently Required for Escape from Hla-B27–Restricted Cytotoxic T Lymphocyte Responses

The immune response to HIV-1 in patients who carry human histocompatibility leukocyte antigen (HLA)-B27 is characterized by an immunodominant response to an epitope in p24 gag (amino acids 263–272, KRWIILGLNK). Substitution of lysine (K) or glycine (G) for arginine (R) at HIV-1 gag residue 264 (R264K and R264G) results in epitopes that bind to HLA-B27 poorly. We have detected a R264K mutation in four patients carrying HLA-B27. In three of these patients the mutation occurred late, coinciding with disease progression. In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype. In each case, R264K was tightly associated with a leucine to methionine change at residue 268. After the loss of the cytotoxic T lymphocyte (CTL) response to this epitope and in the presence of high viral load, reversion to wild-type sequence was observed. In a fifth patient, a R264G mutation was detected when HIV-1 disease progressed. Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260. Phylogenetic analyses indicated that these substitutions emerged under natural selection rather than by genetic drift or linkage. Outgrowth of CTL escape viruses required high viral loads and additional, possibly compensatory, mutations in the gag protein

Megafire:An ambiguous and emotive term best avoided by science

Background: As fire regimes are changing and wildfire disasters are becoming more frequent, the term megafire is increasingly used to describe impactful wildfires, under multiple meanings, both in academia and popular media. This has resulted in a highly ambiguous concept.Approach: We analysed the use of the term ‘megafire’ in popular media to determine its origin, its developments over time, and its meaning in the public sphere. We subsequently discuss how relative the term ‘mega’ is, and put this in the context of an analysis of Portuguese and global data on fire size distribution.Results: We found that ‘megafire’ originated in the popular news media over 20 years before it appeared in science. Megafire is used in a diversity of languages, considers landscape fires as well as urban fires, and has a variety of meanings in addition to size. What constitutes ‘mega’ is relative and highly context-dependent in space and time, given variation in landscape, climate, and anthropogenic controls, and as revealed in examples from the Netherlands, Portugal and the Global Fire Atlas. Moreover, fire size does not equate to fire impact.Conclusion: Given the diverse meanings of megafire in the popular media, we argue that redefining megafire in science potentially leads to greater disparity between science and practice. Megafire is widely used as an emotive term that is best left for popular media. For those wanting to use it in science, what constitutes a megafire should be defined by the context in which it is used, not by a metric of one-size-fits-all.</p