Biology subjects

Kubiseski, T. J.

Publications and source records attributed to Kubiseski, T. J..

3 recordsLinked to original sources

bioRxiv2021

Microfluidic Electric Egg-Laying Assay and Application to In-vivo Toxicity Screening of Microplastics using C. elegans

Environmental pollutants like microplastics are posing health concerns on aquatic animals and the ecosystem. Microplastic toxicity studies using C. elegans as a model are evolving but methodologically hindered from obtaining statistically strong data sets, detecting toxicity effects based on microplastics uptake, and correlating physiological and behavioural effects at an individual-worm level. In this paper, we report a novel microfluidic electric egg-laying assay for phenotypical assessment of multiple worms in parallel. The effects of glucose and polystyrene microplastics at various concentrations on the worms electric egg-laying, length, diameter, and length contraction during exposure to electric signal were studied. The device contained eight parallel worm-dwelling microchannels called electric traps, with equivalent electrical fields, in which the worms were electrically stimulated for egg deposition and fluorescently imaged for assessment of neuronal and microplastic uptake expression. A new bidirectional stimulation technique was developed, and the device design was optimized to achieve a testing efficiency of 91.25%. Exposure of worms to 100mM glucose resulted in a significant reduction in their egg-laying and size. The effects of 1m polystyrene microparticles at concentrations of 100 and 1000 mg/L on the electric egg-laying behaviour, size, and neurodegeneration of N2 and NW1229 (expressing GFP pan-neuronally) worms were also studied. Of the two concentrations, 1000 mg/L caused severe egg-laying deficiency and growth retardation as well as neurodegeneration. Additionally, using single-worm level phenotyping, we noticed intra-population variability in microplastics uptake and correlation with the above physiological and behavioural phenotypes, which was hidden in the population-averaged results. Taken together, these results suggest the appropriateness of our microfluidic assay for toxicological studies and for assessing the phenotypical heterogeneity in response to microplastics.

bioengineering↗

bioRxiv2020

Electric Egg-Laying: Effect of Electric Field in a Microchannel on C. elegans Egg-Laying Behavior

In this paper, the novel effect of electric field (EF) on adult C. elegans egg-laying in a microchannel is discovered and correlated with neural and muscular activities. The quantitative effects of worm aging and EF strength, direction, and exposure duration on egg-laying is studied phenotypically using egg-count, body length, head movement, and transient neuronal activity readouts. Electric egg-laying rate increases significantly when worms face the anode and the response is EF-dependent, i.e. stronger (6V/cm) and longer EF (40s) exposure result in a shorter egg laying response duration. Worm aging significantly deteriorates the electric egg-laying behaviour with 88% decrease in the egg-count from Day-1 to Day-4 post young-adult stage. Fluorescent imaging of intracellular calcium dynamics in the main parts of the egg-laying neural circuit demonstrate the involvement and sensitivity of the serotonergic hermaphrodite specific neurons (HSNs), vulva muscles, and ventral cord neurons to the EF. HSN mutation also results in a reduced rate of electric egg-laying allowing the use of this technique for cellular screening and mapping of the neural basis of electrosensation in C. elegans. This novel assay can be parallelized and performed in a high-throughput manner for drug and gene screening applications.

bioengineering↗

bioRxiv2020

The SEM-4 transcription factor is required for regulation of the oxidative stress response in Caenorhabditis elegans

Oxidative stress causes damage to cells by creating reactive oxygen species (ROS) and the overproduction of ROS have been linked to the onset of premature ageing. We previously found that a brap-2 (BRCA1 associated protein 2) mutant significantly increases the expression of phase II detoxification enzymes in C. elegans. An RNAi suppression screen to identify transcription factors involved in the production of gst-4 mRNA in brap-2 worms identified SEM-4 as a potential candidate. Here, we show that knockdown of sem-4 suppresses the activation of gst-4 caused by the mutation in brap-2. We also demonstrate that sem-4 is required for survival upon exposure to oxidative stress and that SEM-4 is required for expression of the transcription factor SKN-1C. These findings identify a novel role for SEM-4 in ROS detoxification by regulating expression of SKN-1C and the phase II detoxification genes. Article SummaryReactive oxygen species have been implicated as a harmful agent in many age-related diseases as well as an important signaling molecule. The transcription factor SKN-1 in C. elegans is an important regulator of reactive oxygen species levels. Here we show that the transcription factor SEM-4 is required to activate the expression of skn-1c and promote phase II detoxification gene expression. These findings identify a novel role for SEM-4 in regulating reactive oxygen species levels.

genetics↗