Nak H et al. (2019) Biomed Microdevices "A novel micro drill design based on Ros-Drill."

Ergenc AF, Nak H

[Biomed Microdevices, 2019]

This paper presents the development of a novel micro drill device for single living organisms. Currently, microinjection for mice and some other species is performed with the help of piezo-driven actuators with a very small amount of mercury column in the proximal end of the pipette in order to increase the success rate. However, the toxicity of mercury exhibits a risk factor both for the operator and the injected cells. Therefore, mercury-free devices have become a necessity. Here, a novel micro drill is developed based on the same principle of Ros-Drill piercing approach; piercing via rotational movements. The new drill is driven by a brushless motor, and it incorporates the micropipette holder. Both the amplitude and the frequency of rotational oscillations can be adjusted in very wide ranges. The experiments reveal that the drill is suitable for different tasks such as microinjection and biopsy of different organisms. It presents good performance in terms of success rate, ease of usage, compactness and compatibility with different manipulation systems.

Hodgkin J (2017) Genetics "Frontiers of Knowledge: An Interview with 2017 Edward Novitski Prize Recipient Jonathan Hodgkin."

Hodgkin J

[Genetics, 2017]

The Genetics Society of America's Edward Novitski Prize recognizes a single experimental accomplishment or a body of work in which an exceptional level of creativity and intellectual ingenuity has been used to design and execute scientific experiments to solve a difficult problem in genetics. The 2017 winner, Jonathan Hodgkin, used elegant genetic studies to unravel the sex determination pathway in Caenorhabditis elegans He inferred the order of genes in the pathway and their modes of regulation using epistasis analyses-a powerful tool that was quickly adopted by other researchers. He expanded the number and use of informational suppressor mutants in C. elegans that are able to act on many genes. He also introduced the use of collections of wild C. elegans to study naturally occurring genetic variation, paving the way for SNP mapping and QTL analysis, as well as studies of hybrid incompatibilities between worm species. His current work focuses on nematode-bacterial interactions and innate immunity.

Yang WH et al. (2019) J Neurosci Methods "Reflex and habituation behavior of Caenorhabditis elegans assessed by a mechanical vibration system and image analysis."

Chen CY, Yang HC, Kwok HL, Stern A, Wang KL, Lo SJ, Yang WH

[J Neurosci Methods, 2019]

BACKGROUND: The nematodeCaenorhabditis elegans is an emerging invertebrate animal model for investigating neuronal functions in behavioral assays. C. elegans mechanosensation was characterized by the use of a constant mechanical stimulation transmitter followed by quantitative imaging. NEW METHOD: C. elegans reflex and habituation behaviors were characterized by mechanical vibration followed by image analysis. A custom-designed system consists of an aluminum alloy Petri dish holder frame coupled with a mechanical vibration buzzer delivering adjustable pulsed vibration to an agar plate. The basal and evoked movements of C. elegans were recorded by a microscopic digital camera followed by quantitative analysis using microscopic imaging software. RESULTS: Application of the platform inC. elegans was demonstrated with three proof-of-concept experiments: (1) Evaluation of the reflex response stimulated by tapping and mechanical vibration with a mechano-sensation defective mutant. (2) Comparison of the reflex response stimulated by mechanical vibration between wild type and aging mutants. (3) Assessment of the efficacy of the mechanical vibration system on long-term memory for habituation. COMPARISON WITH EXISTING METHODS: Conventional C. elegans mechanosensation techniques depend on stimulation either by manually touching a single animal or tapping the Petri dish followed by scoring via visual observation from the examiner. The mechanical vibration method has greater capacity compared to conventional methods which are labor-intensive, have low throughput and lack quantifiable parameters. CONCLUSIONS: The mechanical vibration system followed by image analysis is a convenient and integrated platform for investigatingC. elegans reflex and habituation in aging and neural behavioral assays.