We describe the fluidFM, an atomic force microscope (AFM) based on hollow cantilevers for local liquid dispensing and stimulation of single living cells under physiological conditions. A nanofluidic ...channel in the cantilever allows soluble molecules to be dispensed through a submicrometer aperture in the AFM tip. The sensitive AFM force feedback allows controlled approach of the tip to a sample for extremely local modification of surfaces in liquid environments. It also allows reliable discrimination between gentle contact with a cell membrane or its perforation. Using these two procedures, dyes have been introduced into individual living cells and even selected subcellular structures of these cells. The universality and versatility of the fluidFM will stimulate original experiments at the submicrometer scale not only in biology but also in physics, chemistry, and material science.
Compared to other photochromophores that show E-Z isomerisation, acylhydrazones are still relatively little explored in the field of liquid crystalline materials. To improve the knowledge about this ...group and their viability as the mesogenic core, herein a series of 10 molecules were synthesised and had their thermal and photoisomerisation properties investigated and correlated to structural changes. Mesomorphism was investigated by POM, DSC, XRD and SAXS techniques (using synchrotron radiation), while photoisomerisation was accompanied by UV-Vis absorption spectroscopy and
1
H NMR measurements. It is demonstrated that the higher the alkoxy chain number, the lower the transition temperatures and the greater the propensity for a columnar arrangement, so that the hexacatenar compounds maintained a Col
h
mesophase at room temperature. On the other hand, a SmC phase was stabilised for low alkoxy chain number and the mesomorphism was extinguished for the non-symmetric structures. All compounds successfully presented E-Z photoisomerisation in solution, being faster for the molecules with the mesogenic core expanded by the addition of a benzoate unit. Overall, this work demonstrates the viability and effectiveness of the use of acylhydrazones in photoisomerizable liquid crystals, showing the advantages compared to other groups and opening an important path for applications based on this photochromophor.
The aim of this systematic review was to investigate the effect of exercise-based programmes in the prevention of non-contact musculoskeletal injuries among football players in comparison to a ...control group.
Systematic review and meta-analysis of randomised controlled trials.
MEDLINE, EMBASE, CENTRAL, CINAHL, PEDro and SPORTDiscus databases were searched from the earliest record to January 2021.
Studies were eligible if they (1) included football players aged 13 years or older, (2) used exercise-based programmes as intervention, (3) presented the number of non-contact musculoskeletal injuries (ie, defined as any acute sudden onset musculoskeletal injury that occurred without physical contact) and exposure hours for each group, and (4) had a control group (eg, usual training, minimal intervention, education). All types of exercise-based prevention programmes were eligible for inclusion. Risk of bias for each included study and overall quality of evidence for the meta-analysis were assessed.
Ten original randomised controlled trials with 13 355 football players and 1 062 711 hours of exposure were selected. Pooled injury risk ratio showed very low-quality evidence that exercise-based prevention programmes reduced the risk of non-contact musculoskeletal injuries by 23% (0.77 (95% CI 0.61 to 0.97)) compared with a control group.
Exercise-based prevention programmes may reduce the risk of non-contact musculoskeletal injuries by 23% among football players. Future high-quality trials are still needed to clarify the role of exercise-based programmes in preventing non-contact musculoskeletal injuries among football players.
CRD42020173017.
We report here an advanced approach for simultaneous and independent submicroscale imaging of local surface charge and topography using microchanneled cantilevers, also known as FluidFM nanopipette ...probes. These hollow cantilevers with a 300 nm opening are employed for ion current measurements that provide access to the local properties of the electrical double layer using the phenomenon of ion current rectification, while also taking advantage of the force sensing capabilities for accurate probe vertical positioning and topography imaging. The independent nature of this atomic force microscope (AFM) feedback opens up a possibility to significantly increase the sensitivity for probing local surface charges in a wider range of salt concentrations, especially in electrolytes of low ionic strength (below 10 mM), where classical local ion conductance measurements with glass nanopipettes would suffer from inaccuracies and instabilities, but where the electrical double layer extends further into the liquid medium and has stronger effect on the measured ion currents for charge imaging. We demonstrate that the measurements with FluidFM do not compromise the positioning accuracy and enable accurate and simultaneous topographical and charge imaging in contact mode (similar to AFM) at high scanning rates, approaching thousands of pixels per second, therefore overtaking state-of-the-art techniques for charge mapping by at least 2 orders of magnitude (the probes reach translation rates of 120 μm s–1 equating to 2 ms per image pixel). We also reveal experimentally the physical limit of this high speed scanning, constrained by the rate of ion redistribution in surface-induced rectification required for double layer sensing and charge mapping.
Isothermal titration calorimetry (ITC) is a technique that measures the heat released or absorbed during a chemical reaction as an intrinsic probe to characterize any chemical process that involves ...heat changes spontaneously occurring during the reaction. The general features of this method to determine the kinetic and thermodynamic parameters of enzymatic reactions (kcat, KM, ΔH) are described and discussed here together with some detailed applications to specific cases. ITC does not require any modification or labeling of the system under analysis, can be performed in solution, and needs only small amounts of enzyme. These properties make ITC an invaluable, powerful, and unique tool to extend the knowledge of enzyme kinetics to drug discovery.
ABSTRACT
Genomic selection offers great potential for increasing the rate of genetic improvement in plant breeding programs. This research used simulation to evaluate the effectiveness of different ...strategies for genotyping and phenotyping to enable genomic selection in early generation individuals (e.g., F2) in breeding programs involving biparental or similar (e.g., backcross or top cross) populations. By using phenotypes that were previously collected in other biparental populations, selection decisions could be made without waiting for phenotypes that pertain directly to the selection candidate to be collected, a process that would take at least three growing seasons. If these phenotypes were collected in biparental populations that were closely related to the selection candidates, only a small number of markers (e.g., 200–500) and a small number of phenotypes (e.g., 1000) were needed to achieve effective accuracy of estimated breeding values. If these phenotypes were collected in biparental populations that were not closely related to the selection candidates, as many as 10,000 markers and 5000 to 20,000 phenotypes were needed. Increasing marker density beyond 10,000 markers did not show benefit and in some scenarios reduced the accuracy of prediction. This study provides a guide, enabling resource allocation to be optimized between genotyping and phenotyping investment dependent on the population under development.
Summary
Aspergillus fumigatus is a fungal pathogen that is capable of adapting to different host niches and to avoid host defenses. An enhanced understanding of how, and which, A. fumigatus signal ...transduction pathways are engaged in the regulation of these processes is essential for the development of improved disease control strategies. Protein phosphatases are central to numerous signal transduction pathways. To comprehend the functions of protein phosphatases in A. fumigatus, 32 phosphatase catalytic subunit encoding genes were identified. We have recognized PtcB as one of the phosphatases involved in the high osmolarity glycerol response (HOG) pathway. The ΔptcB mutant has both increased phosphorylation of the p38 MAPK (SakA) and expression of osmo‐dependent genes. The ΔptcB strain was more sensitive to cell wall damaging agents, had increased chitin and β‐1,3‐glucan, and impaired biofilm formation. The ΔptcB strain was avirulent in a murine model of invasive pulmonary aspergillosis. These results stress the importance of the HOG pathway in the regulation of pathogenicity determinants and virulence in A. fumigatus.
Aspergillus fumigatus is a fungal pathogen that is capable of adapting to different host niches and avoiding host defenses. We have recognized PtcB as a protein phosphatase involved in the HOG (High Osmolarity Glycerol response) pathway. The ΔptcB mutant has both increased phosphorylation of the p38 MAPK (SakA) and expression of osmo‐dependent genes. The ΔptcB strain was avirulent in a murine model of invasive pulmonary aspergillosis, stressing the importance of the HOG pathway in the regulation of pathogenicity and virulence.
Acetaminophen (APAP) is one of the most widely consumed drugs in the world. Studies have shown renal and hepatic damage as the direct result of high oxidative stress induced by APAP. Since the ...cardiovascular system is sensitive to oxidative stress and literature describes increased cardiovascular dysfunction in APAP consumers, this work aimed to evaluate harmful effects of APAP on the vascular system. Rats were exposed to APAP (400 mg/kg/day in drinking water) for 14 days. Plasma and aortas were collected and stored in − 80 °C and a selection of arteries was prepared for isometric tension recordings, morphological, immunohistochemical and protein expression analysis. The APAP-treated group presented increased transaminases (ALT/AST) and malondialdehyde levels in the plasma compared to controls. Lipid peroxidation, glutathione reductase and superoxide dismutase levels were increased in the plasma and arteries of the APAP group. Nevertheless, glutathione level was reduced as compared to control group. The vasodilation response to acetylcholine and sodium nitroprusside (0.1 nM to 10 µM) was also impaired after APAP treatment; however, the vascular relaxation was restored after treatment with vitamin C (100 µM). Arteries from the APAP group presented reduced wall thickness, collagen deposition, elastic fibers and increased immunoreactivity to nitrotyrosine. eNOS and sGC protein expression remained unchanged and were at similar levels as controls. These findings showed higher oxidative stress and impaired vasodilation in rats exposed to APAP. Furthermore, arteries presented reduced cell layers, collagen, elastin deposition and significantly increased immunoreactivity to nitrotyrosine after APAP treatment.
Exogenous aldehydes can cause pain in animal models, suggesting that aldehyde dehydrogenase-2 (ALDH2), which metabolizes many aldehydes, may regulate nociception. To test this hypothesis, we ...generated a knock-in mouse with an inactivating point mutation in ALDH2 (ALDH2*2), which is also present in human ALDH2 of ~540 million East Asians. The ALDH2*1/*2 heterozygotic mice exhibited a larger response to painful stimuli than their wild-type littermates, and this heightened nociception was inhibited by an ALDH2-selective activator (Alda-1). No effect on inflammation per se was observed. Using a rat model, we then showed that nociception tightly correlated with ALDH activity (R(2) = 0.90) and that reduced nociception was associated with less early growth response protein 1 (EGR1) in the spinal cord and less reactive aldehyde accumulation at the insult site (including acetaldehyde and 4-hydroxynonenal). Further, acetaldehyde- and formalin-induced nociceptive behavior was greater in the ALDH2*1/*2 mice than in the wild-type mice. Finally, Alda-1 treatment was even beneficial when given after the inflammatory agent was administered. Our data in rodent models suggest that the mitochondrial enzyme ALDH2 regulates nociception and could serve as a molecular target for pain control, with ALDH2 activators, such as Alda-1, as potential non-narcotic, cardiac-safe analgesics. Furthermore, our results suggest a possible genetic basis for East Asians' apparent lower pain tolerance.
Ewing sarcoma (EWS) is an aggressive bone tumor of uncertain cellular origin. CD99 is a membrane protein that is expressed in most cases of EWS, although its function in the disease is unknown. Here ...we have shown that endogenous CD99 expression modulates EWS tumor differentiation and malignancy. We determined that knocking down CD99 expression in human EWS cell lines reduced their ability to form tumors and bone metastases when xenografted into immunodeficient mice and diminished their tumorigenic characteristics in vitro. Further, reduction of CD99 expression resulted in neurite outgrowth and increased expression of beta-III tubulin and markers of neural differentiation. Analysis of a panel of human EWS cells revealed an inverse correlation between CD99 and H-neurofilament expression, as well as an inverse correlation between neural differentiation and oncogenic transformation. As knockdown of CD99 also led to an increase in phosphorylation of ERK1/2, we suggest that the CD99-mediated prevention of neural differentiation of EWS occurs through MAPK pathway modulation. Together, these data indicate a new role for CD99 in preventing neural differentiation of EWS cells and suggest that blockade of CD99 or its downstream molecular pathway may be a new therapeutic approach for EWS.
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