A Proposal for a Machine Learning Classifier for Viral Infection in Living Cells Based on Mitochondrial Distribution

The study of viral infections using live cell imaging (LCI) is an important area with multiple opportunities for new developments in computational cell biology. Here, this point is illustrated by the analysis of the sub-cellular distribution of mitochondrium in cell cultures infected by Dengue virus (DENV) and in uninfected cell cultures (Mock-infections). Several videos were recorded from the overnight experiments performed in a confocal microscopy of spinning disk. The density distribution of mitochondrium around the nuclei as a function of time and space ρ(r, θ, t) was numerically modeled as a smooth interpolation function from the image data and used in further analysis. A graphical study shows that the behavior of the mitochondrial density is substantially different when the infection is present. The DENV-infected cells show a more diffuse distribution and a stronger angular variation on it. This behavior can be quantified by using some usual image processing descriptors called entropy and uniformity. Interestingly, the marked difference found in the mitochondria density distribution for mock and for infected cell is present in every frame and not an evidence of time dependence was found, which indicate that from the start of the infections the cells are showing an altered subcellular pattern in mitochondrium distribution. Ulteriorly, it would be important to study by analysis of time series for clearing if there is some tendency or approximate cycles. Those findings are suggesting that using the image descriptors entropy and uniformity it is possible to create a machine learning classifier that could recognize if a single selected cell in a culture has been infected or not

Generalized SU(2) Proca theory reconstructed and beyond

As a modified gravity theory that introduces new gravitational degrees of freedom, the generalized SU(2) Proca theory (GSU2P for short) is the non-Abelian version of the well-known generalized Proca theory where the action is invariant under global transformations of the SU(2) group. This theory was formulated for the first time in Phys. Rev. D 94 (2016) 084041, having implemented the required primary constraint-enforcing relation to make the Lagrangian degenerate and remove one degree of freedom from the vector field in accordance with the irreducible representations of the Poincar\'e group. It was later shown in Phys. Rev. D 101 (2020) 045008, ibid 045009, that a secondary constraint-enforcing relation, which trivializes for the generalized Proca theory but not for the SU(2) version, was needed to close the constraint algebra. It is the purpose of this paper to implement this secondary constraint-enforcing relation in GSU2P and to make the construction of the theory more transparent. Since several terms in the Lagrangian were dismissed in Phys. Rev. D 94 (2016) 084041 via their equivalence to other terms through total derivatives, not all of the latter satisfying the secondary constraint-enforcing relation, the work was not so simple as directly applying this relation to the resultant Lagrangian pieces of the old theory. Thus, we were motivated to reconstruct the theory from scratch. In the process, we found the beyond GSU2P.Comment: LaTeX file in RevTeX 4.1 style, 22 pages, no figures. v2: minor changes, including the small change in the title, in order to make the discussion clearer and more accurate. The appendix, having become inconclusive after we recognized that Eq. A19 is not as general as was originally thought, has been removed. Version to be published in Physical Review

Effect of Chitin and Chitooligosaccharide on In vitro Growth of Lactobacillus rhamnosus GG and Escherichia coli TG

Background and Objective: Given the rising tendency of using insects as food, research regarding the food safety issues and health implications of edible insects are necessary. Insects have an external skeleton that is mainly composed of chitin- a nontoxic, fiber-like polysaccharide. Chitin and its derivative compounds can take part in maintaining healthy gut microbiota, by promoting or inhibiting the growth of several gut bacteria depending on the chitinous substrate. Healthy composition of gut microbiota can prevent intestinal disease states and food digestion problems. The aim of the study is to characterize the impact of chitin and chitooligosaccharides on the growth of two gut bacteria Lactobacillus rhamnosus GG and Escherichia coli TG, to provide further understanding on possible outcomes of consuming insects.Materials and Methods: Micro plate wells were prepared with tryptone soy broth in 0.5 and 0.1% wv-1 chitin concentrations and in 0.5, 0.1, and 0.05% wv-1 chitooligosaccharide concentrations. Bacteria were added and the growth parameters of Lactobacillus rhamnosus GG and Escherichia coli TG were obtained by measurement of optical density at 600 nm in 37°C.Results and Conclusion: Chitooligosaccharides enhanced the growth of Lactobacillus rhamnosus GG and inhibited the growth of Escherichia coli TG in the lowest tested concentration of 0.05% wv-1. Chitin completely inhibited the growth of both bacteria in the lowest tested concentration of 0.1% wv-1. Chitooligosaccharides appear promising as potential prebiotic compounds associated with insect food products. Chitin has a strong antibacterial effect on tested bacteria. However, the In vitro results should be verified in well-designed human studies

Conditions of emergence of the Sooty Bark Disease and aerobiology of Cryptostroma corticale in Europe

The sooty bark disease (SBD) is an emerging disease affecting sycamore maple trees (Acer pseudoplatanus) in Europe. Cryptostroma corticale, the causal agent, putatively native to eastern North America, can be also pathogenic for humans causing pneumonitis. It was first detected in 1945 in Europe, with markedly increasing reports since 2000. Pathogen development appears to be linked to heat waves and drought episodes. Here, we analyse the conditions of the SBD emergence in Europe based on a three-decadal time-series data set. We also assess the suitability of aerobiological samples using a species-specific quantitative PCR assay to inform the epidemiology of C. corticale, through a regional study in France comparing two-year aerobiological and epidemiological data, and a continental study including 12 air samplers from six countries (Czechia, France, Italy, Portugal, Sweden and Switzerland). We found that an accumulated water deficit in spring and summer lower than -132 mm correlates with SBD outbreaks. Our results suggest that C. corticale is an efficient airborne pathogen which can disperse its conidia as far as 310 km from the site of the closest disease outbreak. Aerobiology of C. corticale followed the SBD distribution in Europe. Pathogen detection was high in countries within the host native area and with longer disease presence, such as France, Switzerland and Czech Republic, and sporadic in Italy, where the pathogen was reported just once. The pathogen was absent in samples from Portugal and Sweden, where the disease has not been reported yet. We conclude that aerobiological surveillance can inform the spatial distribution of the SBD, and contribute to early detection in pathogen-free countries.O

An Effective Description of the Landscape - II

We continue our analysis of establishing the reliability of "simple" effective theories where massive fields are "frozen" rather than integrated out, in a wide class of four dimensional theories with global or local N=1 supersymmetry. We extend our previous work by adding gauge fields and O(1) Yukawa-like terms for the charged fields in the superpotential. For generic Kaehler potentials, a meaningful freezing is allowed for chiral multiplets only, whereas in general heavy vector fields have to properly be integrated out. Heavy chiral fields can be frozen if they approximately sit to supersymmetric solutions along their directions and, in supergravity, if the superpotential at the minimum is small, so that a mass hierarchy between heavy and light fields is ensured. When the above conditions are met, we show that the simple effective theory is generally a reliable truncation of the full one.Comment: 20 page