Balalaeva, I. V. | bioRxiv Science

bioRxiv2023

Spatial and Temporal Inhomogeneity of Magnetic Background in Cell Culture Experiments: The Role of Type and Position of CO2-Incubator in a Laboratory

In vitro cultivation of cells in strictly controlled conditions of a biological incubator is a widely used experimental model in biological studies. The CO2-incubators allow control of temperature, atmospheric composition, and humidity; however, the recent reports point out at possible significant and incontrollable influence of incubators on magnetic background. We demonstrated that two types of CO2-incubators sufficiently alter the static magnetic field (SMF) in the inner chamber compared to natural geomagnetic field, and the effect depends on the incubator model. The values of SMF in the center of incubators chambers were lower than natural; nevertheless, the strongly expressed spatial inhomogeneity of SMF was registered, with both reduced, up to hypomagnetic, and increased SMF values. One of the incubators in operating mode generated oscillations in magnetic field with period of oscillations about several seconds and peak-to-peak amplitude depending on the measuring point within the chamber volume, up to 115% of the mean value. Since the magnetic background is considered to contribute in multiple biological effects, we emphasize the significant impact of CO2-incubators on magnetic background in cell culture experiments and assume that its spatial and temporal inhomogeneity may be a source for variability in cell study results. HighlightsO_LICO2-incubators sufficiently alter the static magnetic field in the inner chamber compared to natural geomagnetic field C_LIO_LISpatial inhomogeneity of the magnetic field depends on CO2-incubator type and can reach the gradient value of more than 60 T. C_LIO_LIIn one type of the incubator, the generated oscillations in magnetic field were registered with a period of several seconds and a peak-to-peak amplitude up to 115% of the mean value. C_LI

biophysics↗

bioRxiv2021

A novel view on the mechanism of biological activity of antifreeze proteins

The adaptation of organisms to sub-zero temperatures is an intriguing problem in biology and biotechnology. The ice-binding antifreeze proteins are known to be responsible for the adaptation, but the mechanism of their action is still far from being clear. Here we show that: (i) in contrast to common belief, ice-binding proteins do not reduce the water freezing temperature and even raise (1) the ice melting point; (ii) at sub-zero temperatures (to {approx} -30{degrees}C), ice can be formed only on ice-binding surfaces, but, for kinetic reasons, not in bulk water; (iii) living cells have some large surfaces, which can bind the antifreeze proteins. These facts allow suggesting that the task of antifreeze proteins is not to bind to the ice crystals already formed in the cell and stop their growth or rearrangement, but to bind to those cell surfaces where the ice nuclei can form, and thus to prevent ice formation completely.

biophysics↗