Mendoza, Steve et al. (2015) International Worm Meeting "A Novel Worm Tracking Calcium Imaging System Utilizing a Mobile Microscope."

Sherry, Tim, Lam, Brian, Kao, Michelle, Nowak, Nate, Mendoza, Steve, Kim, Taejoon, Arisaka, Katsushi, Madruga, Blake, Jiang, Karen

[International Worm Meeting, 2015]

Worm tracking of freely moving worms is essential to study the connection between behavior and neural activity. However, these microscopes are often limited in their ability to track worms under various behavioral simulations. We present a fluorescence worm tracking microscope that has an open geometry and thus can track worms even if the behavioral platform is difficult or impossible to move via a motorized stage. As opposed to other automated worm tracking systems, our microscope is fully mobile-where all the optical components are mounted on top of a motorized xy stage-while the sample stage where C. elegans rests is stationary. This platform allows for ratiometric calcium imaging while also tracking a dark field worm image for behavioral analysis, running at 15 frames per second. The current configuration has three cameras, two for each of the YFP and CFP channels, and a dark field image showing the worm body, under a 10x magnification; the microscope can also be adjusted to image at 20x. Being able to track freely moving worms without moving the sample stage, allows our microscope to perform worm tracking in experimental conditions that similar systems have not been able to achieve. In addition, since the sample is stationary, we also avoid introducing confounding effects on the worms due to stage acceleration. To test this novel hardware, we run a thermotaxis experiment tracking a worm without moving the temperature platform. Our worm was labeled with AIY::CAM and we find a correlation between the AIY activity and the temperature of the head location during isothermal behavior. Our methodology could also apply to other behavioral experiments where an external stimulus would be hard to move via a motorized stage, such as an electrotaxis experiment.

Madruga, Blake et al. (2017) International Worm Meeting "Development of a SLM-based sheet illumination microscope for rapid, large-scale, video-rate 3-D neurodynamic observation in C. elegans."

Mendoza, Steve, Madruga, Blake, Carmona, Javier, Thatcher, Joe, Arisaka, Katsushi

[International Worm Meeting, 2017]

Sheet Illumination microscopy has made a large impact on the microscopy community due to its many inherent advantages. Increased photonic efficiency allows for lower power light sources, which in turn reduce phototoxic damage to the sample while providing an increased signal to noise ratio. To take advantage of such technique, a type of phase modulator, known as a Spatial Light Modulator (SLM) is used to generate a deep-penetrating, extremely long and narrow Bessel beam interference pattern. Through the use of an SLM, one can easily modulate the phase characteristics of an illumination beam in real time. This property enables greater flexibility and aberration compensation at the sample. The Bessel beams are generated through a bitmap image of the beam's modulation transfer function, which is then displayed on the SLM with a prism phase rotation. This provides a much longer region of micron-order uniformity along the beam axis compared to conventional Gaussian geometries, while shifting the modulated beam away from the higher diffraction orders. The beams are then mapped onto the readout of two scientific CMOS cameras for rapid multi-channel imaging. A piezoelectric objective collar is used to enable rapid z-scanning, thereby creating 4D image volumes with adequate time resolution to characterize and observe active neural dynamics in C. elegans. A long working distance, high numerical aperture (NA), refractive-corrected objective lens is used to study neurobiology and participate in ratiometric calcium imaging. Tools of such flexibility will enable the study of whole-brain-scale neuronal activity and structure under various controlled conditions in C. elegans, over a variety of temporal and spatial scales.

Jiang, Karen et al. (2015) International Worm Meeting "Sensorimotor signal transmission through AIY interneuron in Caenorhabditis elegans during isothermal tracking."

Ling, Linsay, Mendoza, Steve, Sherry, Tim, Nowak, Nathaniel, Arisaka, Katsushi, Jiang, Karen, Haller, Leonard

[International Worm Meeting, 2015]

Perception and navigation through space require accurate translation and transmission of sensory input to motor output. On a linear temperature gradient, Caenorhabditis elegans demonstrate a distinct behavioral phenotype in which they frequently travel along isotherms, maintaining sensitivity within 0.05 degC. This isothermal attractor state is correlated with movement at a constant and maximal velocity. We investigate how AIY, a first layer interneuron and postsynaptic partner to AFD thermosensory neuron, is able to integrate thermal information to return specific well-defined behavioral phenotypes. Prior observations of neural activity in vivo involve partial paralysis or constraint of the worm while stimuli is applied. Other systems circumvent this limitation by re-centering the stage; this generates an external force during stage acceleration introducing another stimulus. We overcome these two primary obstacles through the implementation of a novel automated worm-tracking epi-fluorescent microscope. The three-camera microscope system mounted on a movable XY stage captures dynamic Ca+2 signals in Cameleon-labeled neurons while the nematode navigates unconstrained along the temperature gradient. Implementing this set up, we observed that the greatest temperature difference occurs between the extremes of the head movement while along isotherms which phase lock with fluorescence response in AIY. The steady Ca+2 waveform in AIY suppresses reversals and maintains high speeds to downstream motor circuitry. .

Madruga, Blake et al. (2015) International Worm Meeting "Development of a Bessel Beam Sheet Illumination Microscope for Large-Scale 3-D Neural Dynamics in C. elegans."

Chin, Paul, Arisaka, Katsushi, Madruga, Blake, Carmona, Christopher, Sherry, Tim, Mendoza, Steve, Chen, William, Polanco, Edward

[International Worm Meeting, 2015]

Sheet Illumination has recently amassed a lot of attention as a technique, due to many benefits over standard microscopy methods. Decreased phototoxicity, increased signal to noise ratio, and higher photonic efficiency are only a few of the reasons why many researchers are beginning to answer sensitive scientific questions with sheet illumination microscopy. Due to the unique properties and biological characteristics of C. elegans, access to sheet illumination microscopy is limited, costly, and difficult to utilize. The purpose of designing such a device is to bring the proven benefits of sheet illumination to the C. elegans community, in a intuitive, purposefully-designed manner. A type of phase modulator, known as a Spatial Light Modulator (SLM) is used in this case to generate a specific bessel-beam pattern. Through the use of an SLM, one can easily modulate multiple characteristics of the illuminative beam in real time, enabling great flexibility, ensuring high resolution across multiple scientific applications.Additionally, the use of a piezoelectric objective collar allows the rapid capturing of three dimensional volumes, enabling researchers to examine the dynamics of many neurons in space and time, at sub-micron axial resolution. Such tools will gain access to the observation of large-scale, three dimensional neuronal activity under controlled or experimental conditions in C. elegans, leading to potential scientific discoveries in the future.

Carmona, Javier et al. (2017) International Worm Meeting "2D worm tracking line-confocal microscope with virtual reality."

Wang, Charles, Carmona, Javier, Baldo, Anthony, Madruga, Blake, Mendoza, Steve, Jin, Suying, Arisaka, Katsushi, Liu, Larry, Thatcher, Joseph

[International Worm Meeting, 2017]

Calcium dynamic imaging and free motion tracking coupled with external stimulations allow for in depth analysis of C. elegans behavior. We have developed an integrated platform for monitoring and controlling C. elegans under a variety of external stimulations, including thermal, electrical, and photo stimuli. This innovative platform combines rapid volumetric (20 volume/s) diffraction limited dual line-confocal microscopy (0.5 um x 1 um x 5 um voxel) to determine the neural pathways different external stimuli induce, while tracking worm's two dimensional motion. Never before has dynamic signal propagation, from neuron to neuron, been observed for C. elegans in free motion at such high volume scanning rate. External stimuli are computer controlled with < 10 ms resolution for precise spatio-temporal synchronization with free motion behavior and whole-brain calcium dynamics. Physical linear and circular thermal gradients were implemented using customized temperature plates with thermal fluctuations of less than 0.05 deg C. In addition, thermal stimulation was applied via a 1490 nm infrared laser to create virtual temperature conditions, synchronized with head motion. Infrared laser stimulation allows C. elegans' thermoreceptor (AFD neuron) to perceive temperature fluctuations exclusively in the time domain, thereby allowing for the complete virtual manipulation of the nematode's thermal environment. Electrical responses were induced using a technique that involves applying a linear or spatially alternating electrical field through a gelatin sample with fields ranging from 4 to 14 V/cm. Photon stimulation was implemented using a 405 nm laser with intensities ranging from 0 to 10 mW/mm^2. Volumetric Calcium imaging of QW1217 has also allowed for the complete mapping of the neurons responsible for each of the aforementioned stimuli. The microscope and software accommodate multiple simultaneous stimuli applications, such as electrical and photon simulations. Also tested were the neural pathway differences between infrared and photo avoidance behavior due to their very similar behavioral responses.

Thatcher, Joseph et al. (2017) International Worm Meeting "Development of a three dimensional fluorescence tracking microscope for the motional analysis and behavioral stimulation of C. elegans."

Lam, Brian, Madruga, Blake, Carmona, Javier, Shrestha, Ahis, Jin, Suying, Mendoza, Steve, Thatcher, Joseph, Arisaka, Katsushi, Niaki, Shayan

[International Worm Meeting, 2017]

Extensive advances have been made in understanding the behavior of C. elegans in two dimensional environments. However, they impose substantial constraints on the worm's motion and ultimately restrict the set of possible natural behavioral states it can demonstrate. Addressing limitations encountered by previous efforts in three dimensional imaging, we designed and built a microscope capable of tracking the motion of C. elegans via a set of motorized stages while navigating freely within a sample volume. The variation of gelatin concentration (1% - 4%) and the utilization of temporally controlled ultraviolet photo-stimulation (405 nm) were also incorporated into the system. The addition of a refractive index mismatch correction chamber and fluorescence detection enable novel opportunities for observation and categorization of motion. Preliminary data of photoavoidance response in three dimensions was acquired and demonstrates the added complexity present in an unconstrained response. A novel use of fluorescence enables the identification of C. elegans' absolute orientation with respect to the ventral nerve cord. A model of motion based on sinusoidal wave propagation was applied to C. elegans' forward locomotion, thereby categorizing a set of three dimensional body states inhabited. From this analysis, we have identified three distinct motional states: one of which is sinusoidal in the worm's ventrodorsal plane, another which is sinusoidal in their lateral plane, and a final state that is helical in shape. Fitting this parametric model allows the extraction of a variety of wave-based parameters including wavelength, frequency, wave speed and phase difference which may then be correlated with other dynamic quantities and gelatin concentrations. Namely, the phase difference acts as a direct indicator of the degree to which the worm's posture is planar or helical, allowing the ability to parameterize its general motional form with a single number. Furthermore, from pre-existing, established data of the C. elegans' connectome, we hypothesize a neuronal mechanism for rhythmic signal generation based on the SMD motor neurons which predicts the motional states observed.

Tan, Trudy et al. (2017) International Worm Meeting "Thermotaxis navigational modeling and virtual reality investigation."

Yen, Jessica, Tan, Trudy, Jin, Suying, Zadoorian, Arbi, Arisaka, Katsushi, Huang, Rebecca, Narain, Shreya, D'Orazio, Etta, Yamada, Mandi, Mai, Phat, Park, Jane, Yang, Karen, Carmona, Javier, Kim, Ted, Liu, Junliang, Mendoza, Steve, Watson, Sonya

[International Worm Meeting, 2017]

Caenorhabditis elegans exhibit a well-characterized host of thermosensory behaviors necessary for efficient navigation, foraging, and survival in the natural environment. Many of the neural structures responsible for temperature sensing have evolved to exceptional sensitivity over time, giving rise to cognitively complex, deterministic behaviors such as bias orientation and 90 degree turning. In order to better comprehend the underlying neural circuitry responsible for such behaviors, multiple PID-controlled hardware systems have been constructed to generate and control various thermal gradient conditions within 0.05 degrees C, over durations of ~ 30 minutes. Additionally, an IR laser-based thermosensory system has been fabricated, to provide spatiotemporally controlled thermal stimulus at a highly localized region of the worm's body, enabling the establishment of a virtual thermal environment on which the worm can behave. Using these tools, we have investigated several intricacies of C. elegans' response to temperature, including the mechanism governing 90 degree turns and biased orientation during negative thermotaxis. Making use of line confocal calcium imaging microscopy methods, the dynamics of the AFD sensory neuron and the AIY interneuron were observed, yielding multiple noteworthy datasets. Custom-written MatLab image processing tools based on Goodman and NEMO were utilized to conduct a systematic motional analysis in a variety of experimental thermal conditions. This poster aims to outline the some of these recent advancements in thermotaxis investigation in the Elegant Mind Club, along with preliminary supporting datasets, on a case-by-case basis.

Rabichow, Laura et al. (2017) International Worm Meeting "Photo avoidance reflex influenced by C. elegans' own motional state."

Punjabi, Nihal, Yardley, Reule, Bhagawat, Chaiti, Lee, Diane, Nguyen, Tiffany, Carmona, Javier, Kardoust, Arash, Mohnot, Kushal, Santana, Joslyn, Mendoza, Steve, Rabichow, Laura, McAdam, Meera, Fu, Daniel, Ross, Evan, Mahavni, Anika, Arisaka, Katsushi

[International Worm Meeting, 2017]

Self-awareness is a critical aspect related to the effective navigation of a complex environment. For a given input stimulus to a sensory structure, behavioral output seems closely related to an organism's own motion. An example may be drawn from a relativistic pressure applied to a C. elegans' mechanosensory structure in time, based on two conditions. When considering a mechanical pressure driven by the worm's own motion (as if a worm struck a stationary barrier) the response is dramatically different to one of similar magnitude unrelated to the worm's motion (if a stationary worm was lightly touched with an eyebrow hair). Interestingly, these conditions apply the same force to a given sensory structure in time, but result in a much higher probability of avoidance response if the worm is stationary at the time of the input. To more closely evaluate this complex phenomenon, the well characterized, highly deterministic photo-avoidance behavior was implemented in a number of experimental wave speed conditions. We postulate that a lower avoidance response probability will be found in quickly moving C. elegans as compared to those with slow wave speeds. Gelatin concentration was altered from 1 - 4 % in order to shift the wave speed accordingly, while phototaxis stimulation acted as our input force; provided from a well-calibrated 405nm laser. A custom-built line confocal microscope supplied a triggering signal to the laser stimulus while recording worm position and orientation over experimental trials. Offline, a MatLab program was used to analyze the data and sinusoidally fit an analytic function to the worm's body in time. Wave speed and center of mass velocity were extracted from this data, and avoidance probability was investigated as an independent variable. Preliminarily, observations suggest that lower gelatin concentrations (i.e. faster wave speed) correspond with lower avoidance probability; perhaps due to a partial inhibition of the AVA interneuron through sensorimotor integration.

Clavijo A et al. (2016) Sci Total Environ "The nematode Caenorhabditis elegans as an integrated toxicological tool to assess water quality and pollution."

Kronberg MF, Salatino SE, Clavijo A, Morabito JA, Munarriz ER, Moya A, Calvo D, Pagano EA, Rossen A

[Sci Total Environ, 2016]

Determination of water quality status in rivers is critical to establish a sustainable water management policy. For this reason, over the last decades it has been recommended to perform integrated water assessments that include water quantities and physicochemical, ecological and toxicological tests. However, sometimes resources are limited and it is not possible to perform large-scale chemical determinations of pollutants or conduct numerous ecotoxicological tests. To overcome this problem we use and measure the growth, as a response parameter, of the soil nematode Caenorhabditis elegans to assess water quality in rivers. The C. elegans is a ubiquitous organism that has emerged as an important model organism in aquatic and soil toxicology research. The Tunuyan River Basin (Province of Mendoza, Argentina) has been selected as a representative traditional water monitoring system to test the applicability of the C. elegans toxicological bioassay to generate an integrated water quality evaluation. Jointly with the C. elegans toxic assays, physicochemical and bacteriological parameters were determined for each monitoring site. C. elegans bioassays help to identify different water qualities in the river basin. Multivariate statistical analysis (PCA and linear regression models) has allowed us to confirm that traditional water quality studies do not predict potential toxic effects on living organisms. On the contrary, physicochemical and bacteriological analyzes explain &lt;62% of the C. elegans growth response variability, showing that ecotoxicological bioassays are important to obtain a realistic scenario of water quality threats. Our results confirm that the C. elegans bioassay is a sensible and suitable tool to assess toxicity and should be implemented in routine water quality monitoring.

Kao, Michelle et al. (2015) International Worm Meeting "The Elegant Mind Club: Undergraduate Research Club to Explore the Minds of C. elegans."

Atamdede, Sean, Haller, Leonard, Kao, Michelle, Mendoza, Steve, Madruga, Blake, Agarwal, Neha, Nowak, Nathaniel, Sunyoto, Amanda, Sherry, Tim, Jiang, Karen, Cheng, Shirley, Vanmali, Bobby, Trusz, Guillaume, Arisaka, Katsushi, Pellionisz, Peter, Woolfork, De'Marcu, Sagadevan, Addelyn, Kim, Taejoon, Ling, Linsay, Lam, Brian

[International Worm Meeting, 2015]

For students, the study of model organisms presents an opportunity to learn various general science and research disciplines; however, each model organism has it's own set of advantages. Chiefly, Caenorhabditis elegans are excellent model organisms to study neuroscience and biophysics due to its availability, tractability, relatively simple nervous system, and it's patently observable behavior. Here in the Elegant Mind Club at UCLA, we provide undergraduate students a unique hands-on experience working with C. elegans and a chance to present their own scientific methods of interest, allowing them to explore the nature of scientific research and understand the conclusions drawn from their data. In our laboratory, undergraduate students are entirely responsible for maintaining and culturing the worms as well as building and refining their experimental systems. Direct involvement with the biological samples teaches students the discipline of working with chemicals and maintaining sterility. Published papers and online resources such as WormBook, WormAtlas, and Caenorhabditis Genetics Center provide students with a source of well-established methods and techniques to serve as a basis for their own studies. Manual practice in hardware development permits students to personally hone their experiment to be the most controlled and reproducible systems. As of now, systems for thermotaxis, electrotaxis, chemotaxis, phototaxis, durotaxis, as well as behavior within a magnetic field and the absence of stimuli have been reproduced and improved by our members. Our laboratory begun with a few core members and have expanded to accommodate more than 80 students from different universities over the world and we hope to encourage more students to approach scientific research with enthusiasm.