Maintainence of parasitaemia – is it to die for?

One of the major differences between protozoan differentiation and metazoan differentiation is that protozoan cells normally retain potency during differentiation, which need not, therefore, be considered altruistic. Altruism does, however, arise at the level of the organism and consequently, protozoons have the potential to evolve altruistic traits. This is particularly true when, as with Trypanosoma brucei parasitaemias, populations are genetically homogeneous. This essay argues that whilst reports of altruistic phenomena during the trypanosome life cycle remain controversial, the prospect of reagents able to instigate pathways of cell death or differentiation bears further investigation

Limitation of Trypanosoma brucei parasitaemia results from a combination of density-dependent parasite differentiation and parasite killing by the host immune response

In the bloodstream of its mammalian host, the "slender" form of Trypanosoma brucei replicates extracellularly, producing a parasitaemia. At high density, the level of parasitaemia is limited at a sublethal level by differentiation to the non-replicative "stumpy" form and by the host immune response. Here, we derive continuous time equations to model the time-course, cell types and level of trypanosome parasitaemia, and compare the best fits with experimental data. The best fits that were obtained favour a model in which both density-dependent trypanosome differentiation and host immune response have a role in limiting the increase of parasites, much poorer fits being obtained when differentiation and immune response are considered independently of one another. Best fits also favour a model in which the slender-to-stumpy differentiation progresses in a manner that is essentially independent of the cell cycle. Finally, these models also make the prediction that the density-dependent trypanosome differentiation mechanism can give rise to oscillations in parasitaemia level. These oscillations are independent of the immune system and are not due to antigenic variation

Efficacy of common laboratory disinfectants and heat on killing trypanosomatid parasites

The disinfectants TriGene, bleach, ethanol and liquid hand soap, and water and temperature were tested for their ability to kill bloodstream forms of Trypanosoma brucei, epimastigotes of Trypanosoma rangeli and promastigotes of Leishmania major. A 5-min exposure to 0.2% TriGene, 0.1% liquid hand soap and 0.05% bleach (0.05% NaOCl) killed all three trypanosomatids. Ethanol and water destroyed the parasites within 5 min at concentrations of 15-17.5% and 80-90%, respectively. All three organisms were also killed when treated for 5 min at 50 degrees C. The results indicate that the disinfectants, water and temperature treatment (i.e. autoclaving) are suitable laboratory hygiene measures against trypanosomatid parasites

HVAC Fan Control Using Modicon M580

This project is the start of a lab experiment for the Cal Poly San Luis Obispo Electrical Engineering department’s new lab focusing on Programmable Logic Controller\u27s (PLCs). The primary focus is to create a lab where students control a Heating, Ventilation, and Air conditioning (HVAC) system controlled by the Modicon M580 PLC, donated by Schneider Electric. The experiment contains a heat source, which the PLC monitors with a temperature sensor, and a cooling source with multiple fans. Students will learn to use function block diagrams to program the PLC, controlling fan output and regulating the system temperature. The experiment specifications and HVAC system parameters were created and simulated with the Modicon M580’s software program, Unity Pro XLS. This simulation confirmed a working design that students would be able to recreate themselves in a lab setting and program to work. Students can gain a working knowledge of a commonplace industrial control/automation tool

The Lethal Effects of Herbicides and Herbicide Residues on the Agriculturally Important Wolf Spider Pardosa milvina

Herbicides are applied to commercial crops with increasing frequency and diversity yet are rarely tested for acute or chronic toxicity effects on beneficial non target species such as spiders We measured the lethal effects of chronic exposure to field relevant doses of herbicide treated soil on an agriculturally abundant wolf spider, Pardosa milvina. We tested six herbicides including atrazine, S-metolachlor, mesotrione, glyphosate, 2,4-D, and dicamba. We also tested a mixture of all six herbicides and a distilled water control. Spiders were housed individually in containers with topsoil previously sprayed with a recommended herbicide dosage or water control group To test for herbicide residue effects, we reared spiders under herbicides exposed to three aging treatments freshly applied herbicides, herbicides aged for 69 days under room temperature laboratory conditions (indoor aged) or aged for 69 days in a greenhouse with variable temperature, humidity, light exposure, and evaporative cycling (outdoor aged) (N=960; n= 40 spiders across 24 treatments) Spiders were maintained on these treated substrates for 48 days and fed crickets (Gryllodes sigillatus). We recorded daily mortality across all spider treatments during the testing period Mesotrione and combined herbicide treated spiders showed very high mortality within two weeks of exposure among both freshly applied and indoor aged soil treatments while mortality was modest across outdoor aged herbicide treatments. Our results indicate that some herbicides are arachnicides but require chronic and prolonged exposure to produce lethal effects. Further, soil bacterial communities alone were insufficient to break down herbicides or reduce their toxicity while photodegradation, bacterial action, temperature variation and evaporation cycles were sufficient to dramatically reduce toxicity during chronic exposure

The Creation and Simulation of a Risley Prism Assembly

Intentions of humans revisiting the moon, exploring new planets, and the ever sought out goal of landing humans on Mars is a focus for NASA. With the most recent human missions being the Apollo missions in the 1960's-1970's, upgrades to previous landers are a continuing project. One of the most important and difficult parts of these missions is the landing. An unknown environment and terrain provide challenges for the crew or lander, that may result in broken instruments, overuse of fuel and worst of all, loss of life. The following paper highlights the work done to build a demo lidar scanner for landers and other spacecrafts that touchdown on an alien surface. This instrument intends to provide key information about the surface by creating a three-dimensional map of the terrain in a couple of seconds. Information that can then be used as feedback to the guidance computer and pilots to make an informed decision about a safe landing site. The work is being undertaking by a team at Goddard Spaceflight Center under the electro-mechanical systems branch, and the following represents the work done to create a prototype scanner

Superconductivity and magnetism in platinum-substituted SrFe2As2 single crystals

Single crystals of SrFe2-xPtxAs2 (0 < x < 0.36) were grown using the self flux solution method and characterized using x-ray crystallography, electrical transport, magnetic susceptibility, and specific heat measurements. The magnetic/structural transition is suppressed with increasing Pt concentration, with superconductivity seen over the range 0.08 < x < 0.36 with a maximum transition temperature Tc of 16 K at x = 0.16. The shape of the phase diagram and the changes to the lattice parameters are similar to the effects of other group VIII elements Ni and Pd, however the higher transition temperature and extended range of superconductivity suggest some complexity beyond the simple electron counting picture that has been discussed thus far.Comment: 6 pages, 6 figure

Novel real-time PCR assays for the specific detection of human infective Cryptosporidium species

Cryptosporidium is a protozoan parasite causing gastrointestinal illness. Drinking waterborne outbreaks have been caused by C. hominis, C. parvum and C. cuniculus. Molecular detection techniques already exist for Cryptosporidium and usually target housekeeping genes. We set ourselves the task to identify species-specific genes. These genes are likely to be involved in host parasite interaction and virulence. Three subtelomeric species-specific putative virulence factor genes (Cops-2, Chos-1 and Chos-2) were identified in silico and used to develop novel real-time PCR assays. Our results show that Chos-2 is a suitable target for probe-based assays for the specific detection of C. hominis and C. cuniculus (two very closely related species) and that Cops-2 is a suitable target for specific detection of C. parvum