Biology subjects

Gkantiragas, A.

Publications and source records attributed to Gkantiragas, A..

3 recordsLinked to original sources

bioRxiv2021

A Meta-Analysis of the 16S-rRNA Gut Microbiome Data in Honeybees (Apis Mellifera)

1.Honeybees (Apis Mellifera) perform an essential role in the ecosystem and economy through pollination of insect-pollinated plants, but their population is declining. Many causes of honeybees decline are likely to be influenced by the microbiome which is thought to play an important role in bees and is particularly susceptible to infection and pesticides. However, there has been no systematic review or meta-analysis on honeybee microbiome data. Therefore, we conducted the first systematic meta-analysis of 16S-rRNA data to address this gap in the literature. Four studies were in a usable format - accounting for 336 honeybees worth of data - the largest such dataset to the best of our knowledge. We analysed these datasets in QIIME2 and visualised the results in R-studio. For the first time, we conducted a multi-study evaluation of the core and rare bee microbiome and confirmed previous compositional microbiome data. We established that Snodgrassella, Lactobacillus, Bifidobacterium, Fructobacillus and Saccaribacter form part of the core microbiome and identify 251 rare bacterial genera. Additional components of the core microbiome were likely obscured by incomplete classification. Future studies should refine and add to our existing dataset to produce a more conclusive and high-resolution portrait of the honeybee microbiome. Furthermore, we emphasise the need for an actively curated dataset and enforcement of data sharing standards. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/473299v1_fig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1d9c414org.highwire.dtl.DTLVardef@1d82d2forg.highwire.dtl.DTLVardef@17e6aa1org.highwire.dtl.DTLVardef@8aa415_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1C_FLOATNO Graphical abstract. Made by the author in Biorender.com. C_FIG

ecology↗

bioRxiv2021

Development of an open source program to identify the size of objects using bright-field microscopy - an automated calibration tool

In light microscopy, eyepiece graticules are commonly used to gauge the size of objects at the micron scale. While this is a relatively simple tool to use, not all microscopes possess this feature. Furthermore, calibrating an eyepiece graticule with a stage micrometer can be time-consuming, particularly for inexperienced microscopists. Similarly, calculating the size of individual objects may also take some time. We present an open-source program to determine the size of objects under a microscope using Python and OpenCV. Taking photos of a stage micrometer under a microscope, we identify gradations on the micrometer and calculate the distance between lines on the micrometer in pixels. From this, we can infer the size of objects from bright-field microscopy images. We believe this will improve access to quantitative microscopy techniques and increase the speed at which samples may be analyzed by light microscopy. Future studies may aim to integrate this with machine learning for object identification.

bioinformatics↗

bioRxiv2018

A family of transcription factors that limit lifespan: ETS factors have conserved roles in longevity

Increasing average population age, and the accompanying burden of ill health, is one of the public health crises of our time. Understanding the basic biology of the ageing process may help ameliorate the pathologies that characterise old age. Ageing can be modulated, often through changes in gene expression where regulation of transcription plays a pivotal role. Activities of Forkhead transcription factors (TFs) are known to extend lifespan, but detailed knowledge of the broader transcriptional networks that promote longevity is lacking. This study focuses on the E twenty-six (ETS) family of TFs. This family of TFs is large, conserved across metazoa, and known to play roles in development and cancer, but the role of its members in ageing has not been studied extensively. In Drosophila, an ETS transcriptional repressor, Aop, and an ETS transcriptional activator, Pnt, are known to genetically interact with Foxo and activating Aop is sufficient to extend lifespan. Here, it is shown that Aop and Foxo effect a related gene-expression programme. Additionally, Aop can modulate Foxos transcriptional output to moderate or synergise with Foxo activity depending on promoter context, both in vitro and in vivo. In vivo genome-wide mRNA expression analysis in response to Aop, Pnt or Foxo indicated, and further experiments confirmed, that combinatorial activities of the three TFs dictate metabolic status, and that direct reduction of Pnt activity is sufficient to promote longevity. The role of ETS factors in longevity was not limited to Pnt and Aop. Knockdown of Ets21c or Eip74EF in distinct cell types also extended lifespan, revealing that lifespan is limited by transcription from the ETS binding site in multiple cellular contexts. Reducing the activity of the C. elegans ETS TF Lin-1 also extended lifespan, a finding that corroborates established evidence of roles of this TF family in ageing. Altogether, these results reveal the ETS family of TFs as pervasive and evolutionarily conserved brokers of longevity.

genetics↗