Biology subjects

Arini, G. S.

Publications and source records attributed to Arini, G. S..

5 recordsLinked to original sources

bioRxiv2024

Benefits of combining individual and small group assessments as an instructional strategy

Assessment is an essential curricular component despite being often seen only as a performance metric resource. However, its full potential can be harnessed if it is used as a formative instrument. The present study evaluated the benefits of combining individual and group assessments. Students perceptions of this type of strategy, assessed through a Likert scale questionnaire and semi-structured interviews, showed that students acknowledge the benefits of this procedure. We then carried out a dual assessment in an active learning environment. Students were given individual written tests and completed the same test immediately after, but now in a group. The average group scores were higher than the average individual scores, even for students who scored the highest within a group. Put together, these results indicate combining individual and group assessments can be an effective teaching tool in addition to simply measuring student performance.

scientific communication and education↗

bioRxiv2024

Semi-automated monitoring of longitudinal microbial metabolic dynamics: A study case for lignin degradation

This study introduces a low-cost, open-source, semi-automated bioreactor system, developed using Arduino and Raspberry Pi, for longitudinal microbial culture studies. The system protocol includes detailed instructions for custom-designed components, specifications for easily purchasable parts, and open-source code for a web-based control interface. It was validated for sterility and tested in a case study involving the cultivation of Phanerochaete chrysosporium and Trichoderma reesei to assess their metabolic dynamics, both in isolation and co-culture, for lignin degradation. Using mass spectrometry coupled with gas chromatography, several lignin degradation intermediates were annotated, including 4-hydroxybenzoic acid, vanillic acid, and ferulic acid, along with their temporal variation profiles over 25 days. The results highlighted potential synergy between the two fungal species in lignin breakdown, while also demonstrating the bioreactors flexibility and suitability for diverse biotechnological applications, particularly in the field of bio-degradation and waste valorization.

microbiology↗

bioRxiv2022

Improving annotation propagation on molecular networks through random walks: Introducing ChemWalker

Annotation of the mass signals is still the biggest bottleneck for the untargeted mass spectrometry analysis of complex mixtures. Molecular networks are being increasingly adopted by the mass spectrometry community as a tool to annotate large scale experiments. We have previously shown that the process of propagating annotations from spectral library matches on molecular networks can be automated using Network Annotation Propagation (NAP). One of the limitations of NAP is that the information for the spectral matches is only propagated locally, to the first neighbor of a spectral match. Here we show that annotation propagation can be expanded to nodes not directly connected to spectral matches using random walks on graphs, introducing the ChemWalker python library. Similarly to NAP, ChemWalker relies on combinatorial in silico fragmentation results, performed by MetFrag, searching biologically relevant databases. Departing from the combination of a spectral network and the structural similarity among candidate structures, we have used MetFusion Scoring function to create a weight function, producing a weighted graph. This graph was subsequently used by the random walk to calculate the probability of walking through a set of candidates, departing from seed nodes (represented by spectral library matches). This approach allowed the information propagation to nodes not directly connected to the spectral library match. Compared to NAP, ChemWalker has a series of improvements, on running time, scalability and maintainability and is available as a stand alone python package. ChemWalker is freely available at https://github.com/computational-chemical-biology/ChemWalker.

bioinformatics↗

bioRxiv2021

SARS-CoV-2 activates ER stress and Unfolded protein response

Coronavirus disease-2019 (COVID-19) pandemic caused by the SARS-CoV-2 coronavirus infection is a major global public health concern affecting millions of people worldwide. The scientific community has joint efforts to provide effective and rapid solutions to this disease. Knowing the molecular, transmission and clinical features of this disease is of paramount importance to develop effective therapeutic and diagnostic tools. Here, we provide evidence that SARS-CoV-2 hijacks the glycosylation biosynthetic, ER-stress and UPR machineries for viral replication using a time-resolved (0-48 hours post infection, hpi) total, membrane as well as glycoproteome mapping and orthogonal validation. We found that SARS-CoV-2 induces ER stress and UPR is observed in Vero and Calu-3 cell lines with activation of the PERK-eIF2-ATF4-CHOP signaling pathway. ER-associated protein upregulation was detected in lung biopsies of COVID-19 patients and associated with survival. At later time points, cell death mechanisms are triggered. The data show that ER stress and UPR pathways are required for SARS-CoV-2 infection, therefore representing a potential target to develop/implement anti-CoVID-19 drugs.

biochemistry↗

bioRxiv2020

Distinct photooxidation-induced cell death pathways lead to selective killing of human breast cancer cells

Lack of effective treatments for aggressive breast cancer is still a major global health problem. We previously reported that Photodynamic Therapy using Methylene Blue as photosensitizer (MB-PDT) massively kills metastatic human breast cancer, marginally affecting healthy cells. In this study we aimed to unveil the molecular mechanisms behind MB-PDT effectiveness. Through lipidomic and biochemical approaches we demonstrated that MB-PDT efficiency and specificity relies on polyunsaturated fatty acids-enriched membranes and on the better capacity to deal with photooxidative damage displayed by non-tumorigenic cells. We found out that, in tumorigenic cells, lysosome membrane permeabilization is accompanied by ferroptosis and/or necroptosis. Our results broadened the understanding of MB-PDT-induced photooxidation mechanisms and specificity in breast cancer cells. Therefore, we demonstrated that efficient approaches could be designed on the basis of lipid composition and metabolic features for hard-to-treat cancers. The results further reinforce MB-PDT as a therapeutic strategy for highly aggressive human breast cancer cells.Competing Interest StatementThe authors have declared no competing interest.View Full Text

cancer biology↗