Biophysical Measurements of Cells, Microtubules, and DNA with an Atomic Force Microscope

Atomic force microscopes (AFMs) are ubiquitous in research laboratories and have recently been priced for use in teaching laboratories. Here we review several AFM platforms (Dimension 3000 by Digital Instruments, EasyScan2 by Nanosurf, ezAFM by Nanomagnetics, and TKAFM by Thorlabs) and describe various biophysical experiments that could be done in the teaching laboratory using these instruments. In particular, we focus on experiments that image biological materials and quantify biophysical parameters: 1) imaging cells to determine membrane tension, 2) imaging microtubules to determine their persistence length, 3) imaging the random walk of DNA molecules to determine their contour length, and 4) imaging stretched DNA molecules to measure the tensional force.Comment: 29 page preprint, 7 figures, 1 tabl

Search for correlations between BATSE Gamma-Ray Bursts and Supernovae

We report on complex statistical research of space-time correlated supernovae and CGRO-BATSE gamma-ray bursts. We show that there exists a significantly higher abundanceof core-collapsesup ernovaeamong thecorre lated supernovae, but the subset of all correlated objects does not seem to be physically different from the whole set

Fungal trunk pathogens associated with Juglans regia in the Czech Republic

[EN] Juglans regia L. (English walnut) trees with cankers and dieback symptoms were observed in two regions in the Czech Republic. Isolations were made from diseased branches. In total, 138 fungal isolates representing 10 fungal species were obtained from wood samples and identified based on morphological characteristics and molecular methods: Cadophora novi-eboraci, Cadophora spadicis, Cryptovalsa ampelina, Diaporthe eres, Diplodia seriata, Dothiorella omnivora, Eutypa lata, Ewypella sp., Peroneutypa scoparia, and Phaeoacremonium sicilianum. Pathogenicity tests conducted under field conditions with all species using the mycelium-plug method indicated that Eutypa lata and Cadophora spp. were highly virulent to woody stems of walnut. This is the first study to detect and identify fungal trunk pathogens associated with diseased walnut trees in Europe.This work was supported by the Ministerstvo Skolstvi, Mladeze a Telovychovy (EFRR "Multidisciplinary Research to Increase Application Potential of Nanomaterials in Agricultural Practice," project CZ.02.1.01/0.0/0.0/16_025/0007314). This research was also supported by the Technologicka Agentura Ceske Republiky (project TJ02000096)Eichmeier, A.; Pecenka, J.; Spetik, M.; Necas, T.; Ondrasek, I.; Armengol Fortí, J.; León Santana, M.... (2020). Fungal trunk pathogens associated with Juglans regia in the Czech Republic. Plant Disease. 104:761-771. https://doi.org/10.1094/PDIS-06-19-1308-RES76177110

Bis­(μ-pyridine-2,3-dicarboxyl­ato)bis­[aqua­(3-carb­oxy­pyridine-2-carboxyl­ato)indium(III)] tetra­hydrate

In the binuclear centrosymmetric title compound, [In2(C7H3NO4)2(C7H4NO4)2(H2O)2]·4H2O, which contains both pyridine-2,3-dicarboxyl­ate and 3-carb­oxy­pyridine-2-carboxyl­ate ligands, the InIII atom is six-coordinated in a distorted octa­hedral geometry. One pyridine ligand is N,O-chelated while the other is N,O-chelated and at the same time bridging to the other via the second carboxyl group. In the crystal, an extensive O—H⋯O hydrogen-bonding network, involving the coordinated and lattice water mol­ecules and the carboxyl groups of the ligands, together with C—H⋯O and π–π inter­actions [centroid–centroid distance = 3.793 (1) Å], leads to the formation of a three-dimensional structure

Antisenescence Effect of REAC Biomodulation to Counteract the Evolution of Myelodysplastic Syndrome

About 30 percent of patients diagnosed with myelodysplastic syndromes (MDS) progress to acute myeloid leukemia (AML). The senescence of bone marrow‐derived mesenchymal stem cells (BMSCs) seems to be one of the determining factors in inducing this drift. Research is continuously looking for new methodologies and technologies that can use bioelectric signals to act on senescence and cell differentiation towards the phenotype of interest. The Radio Electric Asymmetric Conveyer (REAC) technology, aimed at reorganizing the endogenous bioelectric activity, has already shown to be able to determine direct cell reprogramming effects and counteract the senescence mechanisms in stem cells. Aim of the present study was to prove if the anti-senescence results previously obtained in different kind of stem cells with the REAC Tissue optimization – regenerative (TO-RGN) treatment, could also be observed in BMSCs, evaluating cell viability, telomerase activity, p19ARF, P21, P53, and hTERT gene expression. The results show that the REAC TORGN treatment may be a useful tool to counteract the BMSCs senescence which can be the basis of AML drift. Nevertheless, further clinical studies on humans are needed to confirm this hypothesis

Shrike predation on the lizard Mesalina adramitana in Qatar; a review of reported reptile and amphibian prey

We report, for the first time, evidence of predation by a shrike (Lanius sp.) on the lizard Mesalina adramitana. This is the first record of predation by shrikes on lizards in Qatar. Whilst we did not directly observe the event, the presence of shrikes in the area and the method of impalement indicate shrikes as the predator. The lizard was found freshly impaled on a palm tree (Phoenix dactylifera), at 150 cm above ground. Bird species of the genus Lanius are well-known predators of lizards, and in arid environments reptiles are likely common prey for these birds. We provide a review of literature concerning predatory events by shrikes on reptiles and amphibians. We suggest inspection of shrubs for animals impaled by shrikes can improve biodiversity inventories, complementing other commonly used methods

Homing and Long-Term Engraftment of Long- and Short-Term Renewal Hematopoietic Stem Cells

Long-term hematopoietic stem cells (LT-HSC) and short-term hematopoietic stem cells (ST-HSC) have been characterized as having markedly different in vivo repopulation, but similar in vitro growth in liquid culture. These differences could be due to differences in marrow homing. We evaluated this by comparing results when purified ST-HSC and LT-HSC were administered to irradiated mice by three different routes: intravenous, intraperitoneal, and directly into the femur. Purified stem cells derived from B6.SJL mice were competed with marrow cells from C57BL/6J mice into lethally irradiated C57BL/6J mice. Serial transplants into secondary recipients were also carried out. We found no advantage for ST-HSC engraftment when the cells were administered intraperitoneally or directly into femur. However, to our surprise, we found that the purified ST-HSC were not short-term in nature but rather gave long-term multilineage engraftment out to 387 days, albeit at a lower level than the LT-HSC. The ST-HSC also gave secondary engraftment. These observations challenge current models of the stem cell hierarchy and suggest that stem cells are in a continuum of change