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1.
Colauto Nelson Barros da Eira Augusto Ferreira Linde Giani Andrea 《World journal of microbiology & biotechnology》2011,27(12):3015-3018
The preservation of Agaricus blazei is generally done by mycelial subculturing, but this technique may cause genetic degenerations. Despite this, there is not
an efficient protocol established to preserve this fungus and cryopreservation could be an alternative. This study aimed to
evaluate two freezing protocols for cryopreservation at −80°C of A. blazei strains. Five fungus strains grown on rice grains with husk and were transferred to glycerol (10%) in cryovials. Next, the
cryovials were submitted to two freezing temperature protocols: (1) cryopreservation starting at 25°C, then at 8°C for 30 min
and kept at −80°C; (2) cryopreservation starting at 25°C, then 8°C for 30 min, −196°C for 15 min and kept at −80°C. After
1 year of cryopreservation, the cryovials were thawed in a water bath at 30°C for 15 min and transferred to malt extract agar
medium. It was concluded that the one-year cryopreservation process of A. blazei, grown on rice grains and cryopreserved at −80°C in glycerol 10%, is viable. The slow freezing, from 8 to −80°C, is effective
whereas the fast freezing, from 8 to −196°C and then to −80°C, is ineffective. The different genetic characteristics among
the strains of this fungus do not interfere in the cryopreservation process. 相似文献
2.
Cold tolerance and dehydration in Enchytraeidae from Svalbard 总被引:4,自引:1,他引:3
L. Sømme T. Birkemoe 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(4):264-269
When cooled in contact with moisture, eight species of arctic Enchytraeidae from Svalbard were killed by freezing within
minutes or hours at −3 and −5 °C; an exception was Enchytraeus kincaidi which survived for up to 2 days. When the temperature approached 0 °C the enchytraeids apparently tried to escape from the
moist soil. The supercooling capacity of the enchytraeids was relatively low, with mean supercooling points of −5 to −8 °C.
In contrast, specimens of several species were extracted from soil cores that had been frozen in their intact state at −15 °C
for up to 71 days. Compared to freezing in a moist environment, higher survival rates were obtained during cooling at freezing
temperatures in dry soil. Survival was recorded in species kept at −3 °C for up to 35 days, and in some species kept at −6 °C
for up to 17 days. Slow warming greatly increased survival rates at −6 °C . The results strongly suggest that arctic enchytraeids
avoid freezing by dehydration at subzero temperatures. In agreement with this, weight losses of up to ca. 42% of fresh weight
were recorded in Mesenchytraeus spp. and of up to 55% in Enchytraeus kincaidi at water vapour pressures above ice at −3 to −6 °C. All specimens survived dehydration under these conditions.
Accepted: 12 December 1997 相似文献
3.
G. N. J. le Patourel 《Entomologia Experimentalis et Applicata》1993,68(3):257-263
The cold-hardiness of nymphal stages 1 to 5 and adult male and femaleBlatta orientalis was tested at 2°, −5° and −10°C. The LT50 (time) of insects exposed to −5° ranged from 0.21 to 0.43 days. Acclimation at
10° C for times varying up to 14 days progressively increased cold-hardiness. A 14 day acclimation at 10° prior to exposure
at −5°C increased LT50 (time) to 1.1–4.2 days for the various stages; prolonging the acclimation time to 28 days produced
no further increase in LT50. All stages were rapidly killed at −10°C (LT50<0.04 days) and survived prolonged exposures at
2°C (LT50s from 16 to >42 days) following acclimation. The potential for survival of outdoor populations ofB. orientalis over winter is discussed. 相似文献
4.
The ability to survive freezing and thawing is a key factor for the existence of life forms in large parts of the world. However,
little is known about the freezing tolerance of mycorrhizal fungi and their role in the freezing tolerance of mycorrhizas.
Threshold temperatures for the survival of these fungi have not been assessed experimentally. We grew isolates of Suillus luteus, Suillus variegatus, Laccaria laccata, and Hebeloma sp. in liquid culture at room temperature. Subsequently, we exposed samples to a series of temperatures between +5°C and
−48°C. Relative electrolyte leakage (REL) and re-growth measurements were used to assess the damage. The REL test indicated
that the lethal temperature for 50% of samples (LT50) was between −8.3°C and −13.5°C. However, in the re-growth experiment, all isolates resumed growth after exposure to −8°C
and higher temperatures. As many as 64% of L. laccata samples but only 11% in S. variegatus survived −48°C. There was no growth of Hebeloma and S. luteus after exposure to −48°C, but part of their samples survived −30°C. The fungi tolerated lower temperatures than was expected
on the basis of earlier studies on fine roots of ectomycorrhizal trees. The most likely freezing tolerance mechanism here
is tolerance to apoplastic freezing and the concomitant intracellular dehydration with consequent concentrating of cryoprotectant
substances in cells. Studying the properties of fungi in isolation promotes the understanding of the role of the different
partners of the mycorrhizal symbiosis in the freezing tolerance. 相似文献
5.
Variation of total soluble seminal root proteins of tetraploid wild and cultivated wheat induced at cold acclimation and freezing 总被引:2,自引:0,他引:2
The relationship between total soluble seminal root proteins induced at cold acclimation and freezing tolerance in tetraploid
wild wheat Aegilops L. (Ae. biuncialis, Ae. cylindrica) and cultivated wheat Triticum turgitum L. (Firat-93, Harran-95) was investigated. Cold acclimation was performed at 0 °C for 7 days. Freezing tolerance was determined
with survived roots after freezing treatments at −5 and/or −7 °C for 3, 6, 12 and 24 h. At −5°C, all tetraploid genotypes
showed over 60% tolerance for 3 h. This effect was also present in wild wheat for 6 h, but was decreased in cultivated wheat
to 30–35% tolerance for 6 h. Only Ae. biuncialis was able to show 52% tolerance just for 3 h freezing period at −7 °C. However, all the genotypes were not survived at −7
°C, for 6, 12 and 24 h. Cold acclimation induced greater amounts of new soluble seminal root proteins in tolerant Ae. biuncialis (29–104 kDa, pI 5.4–7.4) than in sensitive Harran-95 (29–66 kDa, pI 6.1–8.3). Synthesis and accumulation of these proteins
may be related to degree of freezing tolerance of these genotypes. 相似文献
6.
Sunflower seeds behaved as chilling and freezing sensitive and also exhibited acclimation under low seed moisture content
(< 1 %). At high seed moisture content (approx. 22 %) they tolerated chilling stress but failed to acclimate under freezing
temperatures. Pre-imbibitional chilling (5 °C) or freezing (−5 or −10 °C) stress significantly enhanced total soluble protein
(TSP) content. Chilling treatment after imbibition (in contrast to pre-imbibition) enhanced germination and this was accompanied
by increase in 30, 24 and 21.9 kDa TSPs content (3 d after germination). Freezing at −5 and −10 °C suppressed seed germination
and increased content of 78 and 56.2 kDa wall bound proteins. Chilling acclimation decreased 35.4, 33.9, 29.5, 23.4 and 21.4
kDa TSPs. 相似文献
7.
Josef Elster Peter Degma Ľubomír Kováčik Lucia Valentová Katarína Šramková Antonio Batista Pereira 《Biologia》2008,63(6):843-851
The freezing and desiccation tolerance of 12 Klebsormidium strains, isolated from various habitats (aeroterrestrial, terrestrial, and hydro-terrestrial) from distinct geographical
regions (Antarctic — South Shetlands, King George Island, Arctic — Ellesmere Island, Svalbard, Central Europe — Slovakia)
were studied. Each strain was exposed to several freezing (−4°C, −40°C, −196°C) and desiccation (+4°C and + 20°C) regimes,
simulating both natural and semi-natural freeze-thaw and desiccation cycles. The level of resistance (or the survival capacity)
was evaluated by chlorophyll a content, viability, and chlorophyll fluorescence evaluations. No statistical differences (Kruskal-Wallis tests) between strains
originating from different regions were observed. All strains tested were highly resistant to both freezing and desiccation
injuries. Freezing down to −196°C was the most harmful regime for all studied strains. Freezing at −4°C did not influence
the survival of studied strains. Further, freezing down to −40°C (at a speed of 4°C/min) was not fatal for most of the strains.
RDA analysis showed that certain Antarctic and Arctic strains did not survive desiccation at +4°C; however, freezing at −40°C,
as well as desiccation at +20°C was not fatal to them. On the other hand, other strains from the Antarctic, the Arctic, and
Central Europe (Slovakia) survived desiccation at temperatures of +4°C, and freezing down to −40°C. It appears that species
of Klebsormidium which occupy an environment where both seasonal and diurnal variations of water availability prevail, are well adapted to
freezing and desiccation injuries. Freezing and desiccation tolerance is not species-specific nor is the resilience only found
in polar strains as it is also a feature of temperate strains.
Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.
This paper is dedicated to the memory of the late Dr. Bohuslav Fott (1908–1976), Professor of Botany at the Charles University
in Prague, to mark the centenary of his birth. 相似文献
8.
Hayashi M Wharton DA 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(3):335-342
The cold tolerance abilities of only a few nematode species have been determined. This study shows that the oatmeal nematode,
Panagrellus redivivus, has modest cold tolerance with a 50% survival temperature (S
50) of −2.5°C after cooling at 0.5°C min−1 and freezing for 1 h. It can survive low temperatures by freezing tolerance and cryoprotective dehydration; although freezing
tolerance appears to be the dominant strategy. Freezing survival is enhanced by low temperature acclimation (7 days at 5°C),
with the S
50 being lowered by a small but significant amount (0.42°C). There is no cold shock or rapid cold hardening response under the
conditions tested. Cryoprotective dehydration enhances the ability to survive freezing (the S
50 is lowered by 0.55°C, compared to the control, after 4 h freezing at −1°C) and this effect is in addition to that produced
by acclimation. Breeding from survivors of a freezing stress did not enhance the ability to survive freezing. The cold tolerance
abilities of this nematode are modest, but sufficient to enable it to survive in the cold temperate environments it inhabits. 相似文献
9.
Settled zoospores of the green macroalga Enteromorpha intestinalis were subjected to several different freezing and storing
treatments at both cryogenic and non-cryogenic temperatures after which their viability was assessed using a spore germination
bioassay. Three different cooling rates were tested: slow cooling at –1°C min−1 and –0.5°C min−1 to end temperatures in the range –20°C to –40°C, and a two-step procedure whereby the spores were frozen to –30°C at a rate
of –1°C min−1 prior to immersion in liquid nitrogen at –196°C. Spore viability was also investigated using the cryoprotectants glycerol
and dimethyl suphoxide (DMSO), a reduced saline medium and various storage times. In the majority of experiments, the use
of a cryoprotectant during the freezing process significantly increased the viability of the spores, with DMSO affording slightly
greater protection than glycerol. All treatments produced high viabilities (ranging from 75.3–100.0%) after 5-min storage
at the different end temperatures. However, progressively longer storage up to 7 days generally resulted in a marked reduction
in viability. This was with the exception of spores frozen in a reduced saline medium; a medium of 75% seawater and either
5 or 10% DMSO greatly increased spore viability, with values of > 40% recorded for spores stored at –20°C for up to 5 weeks.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
J. P. Costanzo A. L. Allenspach R. E. Lee Jr. 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(4-5):351-359
We investigated function and ultrastructure of sciatic nerves isolated from wood frogs (Rana sylvatica) endemic to the Northwest Territories, Canada, following freezing at −2.5 °C, −5.0 °C, or −7.5 °C. All frogs frozen at −2.5 °C,
and most frogs (71%) frozen at −5.0 °C, recovered within 14 h after thawing began; however, frogs did not survive exposure
to −7.5 °C. Sciatic nerves isolated from frogs frozen at −7.5 °C were refractory to electrical stimulation, whereas those
obtained from frogs surviving exposure to −2.5 °C or −5.0 °C generally exhibited normal characteristics of compound action
potentials. Frogs responded to freezing by mobilizing hepatic glycogen reserves to synthesize the cryoprotectant glucose,
which increased 20-fold in the liver and 40-fold in the blood. Ultrastructural analyses of nerves harvested from frogs in
each treatment group revealed that freezing at −2.5 °C or −5.0 °C had little or no effect on tissue and cellular organization,
but that (lethal) exposure to −7.5 °C resulted in marked shrinkage of the axon, degeneration of mitochondria within the axoplasm,
and extensive delamination of myelin sheaths of the surrounding Schwann cells.
Accepted: 28 April 1999 相似文献
11.
Wen-Jun Wang Fei-Jiu Wang Jian-Yi Zhu Xiu-Tao Sun Chun-Yan Yao Pu Xu 《Journal of applied phycology》2011,23(6):1017-1022
In January and February 2010, heavy sea ice formed along the coast of the Bohai Sea and the northern Yellow Sea, China. Intertidal
organisms were subjected to serious freezing stress. In this study, we investigated the freezing tolerance of the upper intertidal
economic seaweed Porphyra yezoensis. The maximum photochemical efficiency of PS II (F
v/F
m) in undehydrated thalli remained high after 24 h at −2°C and that in dehydrated thalli decreased in a proportion to thallial
water loss. F
v/F
m dropped sharply after 24 h at −20°C, regardless of absolute cellular water content (AWC). The F
v/F
m in frozen thalli recovered rapidly at 0–20°C. A wide range of water loss in the thalli enhanced their tolerance to freezing.
F
v/F
m values in undehydrated thalli dropped sharply after 3 d at −2°C or 10 d at −20°C while those in dehydrated thalli (20–53%
AWCs) remained at high levels after 9 d at −2°C or 30 d at −20°C. These results indicate that P. yezoensis has high freezing tolerance by means of dehydration during the ebb tide and rapid recovery of F
v/F
m from freezing. A strategy of P. yezoensis industry to avoid heavy loss during freezing season is discussed based on these findings. 相似文献
12.
Three species of Arctic to cold-temperate amphi-Atlantic algae, all occurring also in the North Pacific, were tested for growth
and/or survival at temperatures of −20 to 30°C. When isolates from both western and eastern Atlantic shores were tested side-by-side,
it was found that thermal ecotypes may occur in such Arctic algae.Chaetomorpha melagonium was the most eurythermal of the 3 species. Isolates of this alga were alike in temperature tolerance and growth rate but
Icelandic plants were more sensitive to the lethal temperature of 25°C than were more southerly isolates from both east and
west. With regard toDevaleraea ramentacea, one Canadian isolate grew extraordinarily well at −2 and 0°C, and all tolerated temperatures 2–3°C higher than the lethal
limit (18–20°C) of isolates from Europe. ConcerningPhycodrys rubens, both eastern and western isolates died at 20°C but European plants tolerated the lethal high temperature longer, were more
sensitive to freezing, and attained more rapid growth at optimal temperatures. The intertidal species,C. melagonium andD. ramentacea, both survived freezing at −5 and −20°C, at least for short time periods.C. melagonium was more susceptible thanD. ramentacea to desiccation. Patterns of thermal tolerance may provide insight into the evolutionary history of seaweed species. 相似文献
13.
M. Jose Comez-L Pilar Lopez Jose V. Castell 《In vitro cellular & developmental biology. Plant》1984,20(11):826-832
Summary The present study was undertaken to define the conditions for optimal cryopreservation of hepatocytes. Two different freezing
procedures were analyzed: a slow freezing rate (SFR) (−2° C/min down to −30°C and then quick freezing to −196° C) and a fast
freezing rate (FFR) (direct freezing of tubes to −196° C: −39° C/min). Cells were frozen in fetal bovine serum containing
10% Dimethyl sulfoxide (DMSO). After rapid thawing at 37° C, followed by dilution and removal of the cryoprotectant, cells
were plated and several parameters were followed as criteria for optimal cryopreservation of cells. The FFR cells showed no
apparent ultrastructural damage after 24 h of culture. Plating efficiency and spreading were similar as controls. Gluconeogenesis
from pyruvate and fructose, tyrosine amino transferase induction by glucagon and dexamethasone, urea production, and plasma
protein synthesis of FFR cells were similar to those found in control cultures. The FFR procedure, in comparison to the SFR
method, seemed to render the best preserved hepatocytes.
The financial support for this work was from Fondo de Investigaciones Sanitarias de la Seguridad Social, Grants 41/82 and
48/82. 相似文献
14.
Hydromedion sparsutum is a locally abundant herbivorous beetle on the sub-Antarctic island of South Georgia, often living in close association
with the tussock grass Parodiochloa flabellata. Over a 4-day period in mid-summer when the air temperature varied from 0 to 20°C, the temperature in the leaf litter 5–10 cm
deep at the base of tussock plants (the microhabitat of H. sparsutum) was consistently within the range of 5–7.5°C. Experiments were carried out to assess the ability of H. sparsutum larvae collected from this thermally stable environment to acclimate when maintained at lower (0°C) and higher (15°C) temperatures.
The mean supercooling points (freezing temperature) of larvae collected in January and acclimated at 0°C for 3 and 6 weeks
and 15°C for 3 weeks were all within the range of −2.6 to −4.6°C. Larvae in all treatment groups were freeze tolerant. Acclimation
at 0°C significantly increased survival in a 15-min exposure at −8°C (from 27 to 96%) and −10°C (from 0 to 63%) compared with
the field-fresh and 15°C-treated larvae. Similarly, survival of 0°C-acclimated larvae in a 72-h exposure at −6°C increased
from 20 to 83%. Extending the acclimation period at 0°C to 6 weeks did not produce any further increase in cold tolerance.
The concentrations of glucose and trehalose in larval body fluids increased significantly with low temperature acclimation.
Larvae maintained at 15°C for 3 weeks (none survived for 6 weeks) were less able to survive 1-h exposures between 30 and 35°C
than the 0°C-treated samples. Whilst vegetation and snow cover are an effective buffer against low winter temperatures in
many polar insects, the inability of H. sparsutum larvae to acclimate or survive at 15°C suggests that protection against high summer temperatures is equally important for
this species.
Accepted: 2 August 1999 相似文献
15.
16.
Todd Sformo F. Kohl J. McIntyre P. Kerr J. G. Duman B. M. Barnes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(7):897-902
Freeze tolerance and freeze avoidance are typically described as mutually exclusive strategies for overwintering in animals.
Here we show an insect species that combines both strategies. Individual fungus gnats, collected in Fairbanks, Alaska, display
two freezing events when experimentally cooled and different rates of survival after each event (mean ± SEM: −31.5 ± 0.2°C,
70% survival and −50.7 ± 0.4°C, 0% survival). To determine which body compartments froze at each event, we dissected the abdomen
from the head/thorax and cooled each part separately. There was a significant difference between temperature levels of abdominal
freezing (−30.1 ± 1.1°C) and head/thorax freezing (−48.7 ± 1.3°C). We suggest that freezing is initially restricted to one
body compartment by regional dehydration in the head/thorax that prevents inoculative freezing between the freeze-tolerant
abdomen (71.0 ± 0.8% water) and the supercooled, freeze-sensitive head/thorax (46.6 ± 0.8% water). 相似文献
17.
M. Holmstrup L. Sømme 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1998,168(3):197-203
Specimens of the Arctic Collembolon Onychiurus arcticus were exposed to desiccation at several subzero temperatures over ice and at 0.5 °C over NaCl solutions. The effects of desiccation
on water content (WC), body fluid melting point (MP), supercooling point (SCP) and survival were studied at several acclimation
temperatures and relative humidities. Exposure to temperatures down to −19.5 °C caused a substantial and increasing dehydration.
At the lowest exposure temperature unfrozen individuals lost 91.6% of the WC at full hydration but more than 80% of the individuals
survived when rehydrated. Exposure at 0.5 °C to decreasing relative humidities (RH) from 100% to 91.3% caused increasing dehydration
and increasing mortality. Survival of equally dehydrated individuals was higher at subzero temperatures than at 0.5 °C. Concurrent
with the decline in WC a lowering of the MP was observed. Animals exposed to −3 °C and −6 °C over ice for 31 days had a MP
of −3.8 and < −7.5 °C, respectively. Specimens from a laboratory culture had a mean SCP of −6.1 °C, and acclimation at 0 or
−3 °C had little effect on SCPs. Exposure at −8.2 °C over ice for 8 days, however, caused the mean SCP to decline to −21.8 °C
due to the severe dehydration of these individuals. Dehydration at 0.5 °C in 95.1 and 93.3% RH also caused a decline in SCPs
to about −18 °C. Individuals that had been acclimated over ice at −12.4 °C or at lower temperatures apparently did not freeze
at all when cooled to −30 °C, probably because all freezeable water had been lost. These results show that O. arcticus will inevitably undergo dehydration when exposed to subzero temperatures in its natural frozen habitat. Consequently, the
MP and SCP of the Collembola are substantially lowered and in this way freezing is avoided. The increased cold hardiness by
dehydration is similar to the protective dehydration mechanism described in earthworm cocoons and Arctic enchytraeids.
Accepted: 5 January 1998 相似文献
18.
19.
Biogeographic studies separate the Antarctic Notothenioid fish fauna into high- and low-latitude species. Past studies indicate
that some species found in the high-latitude freezing waters of the High-Antarctic Zone have low-serum hysteresis freezing
points, while other species restricted to the low-latitude seasonal pack ice zone have higher serum hysteresis freezing points
above the freezing point of seawater (−1.9°C), but the relationship has not been systematically investigated. Freeze avoidance
was quantified in 11 species of Antarctic icefishes by determining the hysteresis freezing points of their blood serum, in
addition, the freezing point depression from serum osmolytes, the antifreeze activity from serum antifreeze glycoproteins
(AFGPs), and the antifreeze activity from serum antifreeze potentiating protein were measured for each species. Serum hysteresis
freezing point, a proxy for organismal freeze avoidance, decreased as species were distributed at increasing latitude (linear
regression r
2 0.66, slope −0.046°C °latitude−1), which appeared largely independent of phylogenetic influences. Greater freeze avoidance at high latitudes was largely a
result of higher levels of antifreeze activity from serum AFGPs relative to those in species inhabiting the low-latitude waters.
The icefish fauna could be separated into a circum High-Antarctic Group of eight species that maintained serum hysteresis
freezing points below −1.9°C even when sampled from less severe habitats. The remaining three species with low-latitude ranges
restricted to the waters of the northern part of the west Antarctic Peninsula and Scotia Arc Islands had serum hysteresis
freezing points at or above −1.9°C due to significantly lower combined activity from all of their serum antifreeze proteins
than found in the High-Antarctic Zone icefish. 相似文献
20.
J. P. Costanzo J. B. Moore R. E. Lee Jr. P. E. Kaufman J. A. Wyman 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(3):169-176
This investigation examined the influence of soil moisture and associated parameters on the cold hardiness of the Colorado
potato beetle (Leptinotarsa decemlineata Say), a temperate-zone species that overwinters in terrestrial burrows. The body mass and water content of adult beetles
kept in sand at 4 °C varied over a 16-week period of diapause according to the substratum's moisture content. Changes in body
water content, in turn, influenced the crystallization temperature (range −3.3 to −18.4 °C; n = 417), indicating that environmental moisture indirectly determined supercooling capacity, a measure of physiological cold
hardiness. Beetles held in dry sand readily tolerated a 24-h exposure to temperatures ranging from 0° to −5 °C, but those
chilled in sand containing as little as 1.7% water (dry mass) had elevated mortality. Thus, burrowing in dry soils not only
promotes supercooling via its effect on water balance, but may also inhibit inoculative freezing. Mortality of beetles exposed
to −5 °C for 24 h was lower in substrates composed of sand, clay and/or peat (36–52%) than in pure silica sand (78%) having
an identical water content (17.0% dry mass). In addition to moisture, the texture, structure, water potential, and other physico-chemical
attributes of soil may strongly influence the cold hardiness and overwintering survival of burrowing insects.
Accepted: 10 September 1996 相似文献