Dataset: Chemotactic response of Vibrio alginolyticus

Methods & Sampling

Vibrio alginolyticus (YM4; wild-type) from -80℃ stock were grown overnight in Marine 2216 media (Difco) by incubating at 30℃ and shaking at 600 revolutions per minute (RPM). The overnight culture was diluted 100-fold into fresh pre-warmed 2216 media and grown for three hours (30℃, shaking at 600 RPM) to O.D. ≈ 0.2. 2 ml of culture was then washed and resuspended (1,500 RCF for 5 min) in 0.5ml of artificial seawater (ASW).

Artificial seawater (ASW) was prepared following the NCMA ESAW Medium recipe, which was adapted from Harrison et al.and modified by Berges, and filtered through a 0.2um filter immediately prior to use.

A simple three-inlet gradient generation microfluidic device was used to produce the chemical gradients.  Microfluidic devices were made using standard soft lithography techniques. Polydimethylsiloxane (Dow Corning SYLGARD 184) channels were cast on photoresist (Microchem) molds fabricated via photolithography and plasma bonded to standard glass slides. Gradient generation channels were designed with three inlets (width 0.5mm) carrying the chemostimulus solution, cell suspension and ASW media, respectively. Prior to use, the chambers were pretreated with a 0.5% BSA solution to mitigate cell adhesion. The three solutions were flow stratified for a minimum of 2min using a syringe pump(Harvard Apparatus), whereby flow rates were adjusted to maintain a 4:1:4 ratio of the stream widths. Upon halting the flow, a monotonic chemotaxis profile was established through diffusion. A chemostimulus gradient develops in the channel via diffusion, and the chemotactic response of the cell population was observed over time. Imaging was performed with phasecontrast microscopy (4×, 0.13 NA objective; Nikon Ti-E) at 1 fps over the course of ~10 min using a CMOS camera (Blackfly S, Teledyne FLIR). An example of the gradient generator used can be found in http://dx.doi.org/10.1038/s41567-021-01247-7

This data set summarises the chemotactic response of a model marine bacteria (Vibrio alginolyticus YM4 wild-type) to filtered exudates of the cyanobacteria Synechococcus sp WH8102. Two filtrate sets were collected, each spanning 6 time points (named T1 -> T6), with the inital assays split into 4 biological replicates (named A, B, C, D). The two treatments were:

1). A control treatment (named "Control", or shortened to "C")

2). A phage-infected treatment (named "Phage", or shortened to "P"), where host Synechococcus were infected with the T-4 like Myovirus S-SSM5, with data collected over the pre-lysis cycle.

These treatments are fully described in: https://doi.org/10.1038/s43705-022-00169-6. The filtrates were kept frozen at -80C in 1ml aliquots, and only thawed to room temperature immediately prior to experimental use.

For each time point (T1-6), and replicate (A-D), three sets of chemotaxis assays were collected: Phage vs ASW, Control vs ASW, and Phage vs Control. (Each with three biological replicates with fresh cell suspensions, with three physical replicates per sample, totaling nine samples at each time point/sample replicate). The chemotactic preference of Vibrio alginolyticus was measured by analyzing the cell distribution over time, and comparing the cell populations on opposite sides of the channel.