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Frost is a thin layer of ice on a solid surface, which forms from water vapor that deposits onto a freezing surface. Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is similar to the formation of dew, except it occurs below the freezing point of water typically without crossing through a liquid state.
The term cryostasis was introduced to name the reversible preservation technology for live biological objects which is based on using clathrate-forming gaseous substances under increased hydrostatic pressure and hypothermic temperatures.
Cryobiology is the branch of biology that studies the effects of low temperatures on living things within Earth's cryosphere or in science. The word cryobiology is derived from the Greek words κρῧος [kryos], "cold", βίος [bios], "life", and λόγος [logos], "word". In practice, cryobiology is the study of biological material or systems at temperatures below normal. Materials or systems studied may include proteins, cells, tissues, organs, or whole organisms. Temperatures may range from moderately hypothermic conditions to cryogenic temperatures.
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid. It is achieved in the absence of a seed crystal or nucleus around which a crystal structure can form. The supercooling of water can be achieved without any special techniques other than chemical demineralization, down to −48.3 °C (−54.9 °F). Droplets of supercooled water often exist in stratus and cumulus clouds. An aircraft flying through such a cloud sees an abrupt crystallization of these droplets, which can result in the formation of ice on the aircraft's wings or blockage of its instruments and probes.
Acclimatization or acclimatisation is the process in which an individual organism adjusts to a change in its environment, allowing it to maintain fitness across a range of environmental conditions. Acclimatization occurs in a short period of time, and within the organism's lifetime. This may be a discrete occurrence or may instead represent part of a periodic cycle, such as a mammal shedding heavy winter fur in favor of a lighter summer coat. Organisms can adjust their morphological, behavioral, physical, and/or biochemical traits in response to changes in their environment. While the capacity to acclimate to novel environments has been well documented in thousands of species, researchers still know very little about how and why organisms acclimate the way that they do.
Antifreeze proteins (AFPs) or ice structuring proteins refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water. AFPs bind to small ice crystals to inhibit the growth and recrystallization of ice that would otherwise be fatal. There is also increasing evidence that AFPs interact with mammalian cell membranes to protect them from cold damage. This work suggests the involvement of AFPs in cold acclimatization.
Psychrophiles or cryophiles are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from −20 °C (−4 °F) to 20 °C (68 °F). They are found in places that are permanently cold, such as the polar regions and the deep sea. They can be contrasted with thermophiles, which are organisms that thrive at unusually high temperatures, and mesophiles at intermediate temperatures. Psychrophile is Greek for 'cold-loving', from Ancient Greek ψυχρός (psukhrós) 'cold, frozen'.
Cold hardening is the physiological and biochemical process by which an organism prepares for cold weather.
Plasmodesmata are microscopic channels which traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them. Plasmodesmata evolved independently in several lineages, and species that have these structures include members of the Charophyceae, Charales, Coleochaetales and Phaeophyceae, as well as all embryophytes, better known as land plants. Unlike animal cells, almost every plant cell is surrounded by a polysaccharide cell wall. Neighbouring plant cells are therefore separated by a pair of cell walls and the intervening middle lamella, forming an extracellular domain known as the apoplast. Although cell walls are permeable to small soluble proteins and other solutes, plasmodesmata enable direct, regulated, symplastic transport of substances between cells. There are two forms of plasmodesmata: primary plasmodesmata, which are formed during cell division, and secondary plasmodesmata, which can form between mature cells.
A cryoprotectant is a substance used to protect biological tissue from freezing damage. Arctic and Antarctic insects, fish and amphibians create cryoprotectants in their bodies to minimize freezing damage during cold winter periods. Cryoprotectants are also used to preserve living materials in the study of biology and to preserve food products.
Insect winter ecology describes the overwinter survival strategies of insects, which are in many respects more similar to those of plants than to many other animals, such as mammals and birds. Unlike those animals, which can generate their own heat internally (endothermic), insects must rely on external sources to provide their heat (ectothermic). Thus, insects persisting in winter weather must tolerate freezing or rely on other mechanisms to avoid freezing. Loss of enzymatic function and eventual freezing due to low temperatures daily threatens the livelihood of these organisms during winter. Not surprisingly, insects have evolved a number of strategies to deal with the rigors of winter temperatures in places where they would otherwise not survive.
A pulvinus is a joint-like thickening at the base of a plant leaf or leaflet that facilitates growth-independent movement. Pulvini are common, for example, in members of the bean family Fabaceae (Leguminosae) and the prayer plant family Marantaceae.
A eurytherm is an organism, often an endotherm, that can function at a wide range of ambient temperatures. To be considered a eurytherm, all stages of an organism's life cycle must be considered, including juvenile and larval stages. These wide ranges of tolerable temperatures are directly derived from the tolerance of a given eurythermal organism's proteins. Extreme examples of eurytherms include Tardigrades (Tardigrada), the desert pupfish, and green crabs, however, nearly all mammals, including humans, are considered eurytherms. Eurythermy can be an evolutionary advantage: adaptations to cold temperatures, called cold-eurythemy, are seen as essential for the survival of species during ice ages. In addition, the ability to survive in a wide range of temperatures increases a species' ability to inhabit other areas, an advantage for natural selection.
Cryopreservation or cryoconservation is a process where biological material - cells, tissues, or organs - are frozen to preserve the material for an extended period of time. At low temperatures any cell metabolism which might cause damage to the biological material in question is effectively stopped. Cryopreservation is an effective way to transport biological samples over long distances, store samples for prolonged periods of time, and create a bank of samples for users. Molecules, referred to as cryoprotective agents (CPAs), are added to reduce the osmotic shock and physical stresses cells undergo in the freezing process. Some cryoprotective agents used in research are inspired by plants and animals in nature that have unique cold tolerance to survive harsh winters, including: trees, wood frogs, and tardigrades.
RiAFP refers to an antifreeze protein (AFP) produced by the Rhagium inquisitor longhorned beetle. It is a type V antifreeze protein with a molecular weight of 12.8 kDa; this type of AFP is noted for its hyperactivity. R. inquisitor is a freeze-avoidant species, meaning that, due to its AFP, R. inquisitor prevents its body fluids from freezing altogether. This contrasts with freeze-tolerant species, whose AFPs simply depress levels of ice crystal formation in low temperatures. Whereas most insect antifreeze proteins contain cysteines at least every sixth residue, as well as varying numbers of 12- or 13-mer repeats of 8.3-12.5kDa, RiAFP is notable for containing only one disulfide bridge. This property of RiAFP makes it particularly attractive for recombinant expression and biotechnological applications.
Zhang Wenhao, also known as Wen-Hao Zhang, is a Chinese plant physiologist and nutritionist at the Institute of Botany, Chinese Academy of Sciences.
In plant biology, thermonasty is a nondirectional response to temperature in plants. It is a form of nastic movement, not to be confused with thermotropism, which is a directional response in plants to temperature. A common example of this is in some Rhododendron species, but thermonasty has also been observed in other plants, such as Phryma leptostachya. Flower opening in certain crocus and tulip species is also known to be thermonastic. These movements are thought to be regulated by having unequal cell elongation in certain plant tissues, causing different tissues to bend. In other processes, like in the temperature regulation of flower openings, movement has instead been shown to be a result of irreversible cell growth, a growth type not typically associated with plant movement. Furthermore, thermonasty has been shown to be independent of other environmental signals, such as light and gravity.
Dendroides canadensis, the fire-colored beetle, is a species of fire-colored beetle in the family Pyrochroidae from southeastern Canada and the eastern and central United States. This beetle has both the adaptations of freezing tolerance and freezing susceptibility (supercooling).
Notothenia coriiceps, also known as the black rockcod, Antarctic yellowbelly rockcod, or Antarctic bullhead notothen, is a species of marine ray-finned fish, belonging to the family Nototheniidae, the notothens or cod icefishes. It is widely spread around the Antarctic continent. Like other Antarctic notothenioid fishes, N. coriiceps evolved in the stable, ice-cold environment of the Southern Ocean. It is not currently targeted by commercial fisheries.
Calcium signaling in Arabidopsis is a calcium mediated signalling pathway that Arabidopsis plants use in order to respond to a stimuli. In this pathway, Ca2+ works as a long range communication ion, allowing for rapid communication throughout the plant. Systemic changes in metabolites such as glucose and sucrose takes a few minutes after the stimulus, but gene transcription occurs within seconds. Because hormones, peptides and RNA travel through the vascular system at lower speeds than the plants response to wounds, indicates that Ca2+ must be involved in the rapid signal propagation. Instead of local communication to nearby cells and tissues, Ca2+ uses mass flow within the vascular system to help with rapid transport throughout the plant. Ca2+ moving through the xylem and phloem acts through a “calcium signature” receptor system in cells where they integrate the signal and respond with the activation of defense genes. These calcium signatures encode information about the stimulus allowing the response of the plant to cater towards the type of stimulus.
References
- ↑ Hon, W. C.; Griffith, M.; Mlynarz, A.; Kwok, Y. C.; Yang, D. S. (1995). "Antifreze proteins in winter rye are similar to pathogenesis-related proteins". Plant Physiology. 109 (3): 879–889. doi:10.1104/pp.109.3.879. PMC 161389 . PMID 8552719.
- ↑ Gilmour, Sarah J.; Hajela, Ravindra K.; Thomashow, Michael F. (1988-07-01). "Cold Acclimation in Arabidopsis thaliana1". Plant Physiology. 87 (3): 745–750. doi:10.1104/pp.87.3.745. ISSN 0032-0889. PMC 1054832 . PMID 16666219.
- ↑ Yaish, M. W.; Doxey, A. C.; McConkey, B. J.; Moffatt, B. A.; Griffith, M. (2006). "Cold-active winter rye glucanases with ice-binding capacity". Plant Physiology. 141 (4): 1459–1472. doi:10.1104/pp.106.081935. PMC 1533947 . PMID 16815958.
- ↑ Thomashow, M (1998). "Role of cold-responsive genes in plant freezing tolerance". Plant Physiology. 118 (1): 1–8. doi:10.1104/pp.118.1.1. PMC 1539187 . PMID 9733520.
- ↑ Whitlow, Thomas H.; Bassuk, Nina L.; Ranney, Thomas G.; Reichert, Deborah L. (1992-01-01). "An Improved Method for Using Electrolyte Leakage to Assess Membrane Competence in Plant Tissues". Plant Physiology. 98 (1): 198–205. doi:10.1104/pp.98.1.198. ISSN 0032-0889. PMC 1080169 . PMID 16668614.
- ↑ Storey, K.B.; Storey, J.M. (2017). "Molecular physiology of freeze tolerance in vertebrates". Physiological Reviews. 97 (2): 623–665. doi: 10.1152/physrev.00016.2016 . PMID 28179395.
- ↑ Storey, K.B. "Freeze Tolerance". The Storey Lab: Cell and Molecular Responses to Stress. Retrieved November 19, 2018.