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At least six major areas of cryobiology can be identified: 1) study of cold-adaptation of microorganisms, plants (cold hardiness), and animals, both invertebrates and vertebrates (including hibernation), 2) cryopreservation of cells, tissues, gametes, and embryos of animal and human origin for (medical) purposes of long-term storage by cooling to temperatures below the freezing point of water.
Freezing temperatures curb the spoiling effect of microorganisms in food, but can also preserve some pathogens unharmed for long periods of time. Freezing kills some microorganisms by physical trauma, others are sublethally injured by freezing, and may recover to become infectious.
Most bacteria have not been characterised and there are many species that cannot be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology. Like all animals, humans carry vast numbers (approximately 10 13 to 10 14) of bacteria. [3] Most are in the gut, though there are many on the
When bacteria is in an area of very low and cold temperature, they will have a five hour long phase that will cause them not to grow at all. The way the bacteria tries to adapt is by creating cold shock proteins that will be transcription factors that will be upregulated during the five hour phase. Once this five hour period ends, the bacteria ...
Most plants, in particular, can safely reach temperatures of −4 °C to −12 °C. Certain bacteria, notably Pseudomonas syringae, produce specialized proteins that serve as potent ice nucleators, which they use to force ice formation on the surface of various fruits and plants at about −2 °C. [9] The freezing causes injuries in the ...
Depending on temperature, bacteria can be classified as: Psychrophiles; Psychrophiles are extremophilic cold-loving bacteria or archaea with an optimal temperature for growth at about 15 °C or lower (maximal temperature for growth at 20 °C, minimal temperature for growth at 0 °C or lower). Psychrophiles are typically found in Earth's ...
Free living cells desiccate and vitrify between −10 °C and −26 °C. Cells of multicellular organisms may vitrify at temperatures below −50 °C. The cells may continue to have some metabolic activity in the extracellular fluid down to these temperatures, and they remain viable once restored to normal temperatures. [2]
Controlled-rate and slow freezing, also known as slow programmable freezing (SPF), [18] is a technique where cells are cooled to around -196 °C over the course of several hours. Slow programmable freezing was developed during the early 1970s, and eventually resulted in the first human frozen embryo birth in 1984. Since then, machines that ...