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1.
Andrade MG Sá CN Marchionni AM dos Santos Calmon de Bittencourt TC Sadigursky M 《Cell and tissue banking》2008,9(4):279-287
Allograft bone has been widely used for reconstruction of different portions of the skeleton. The fragment of bone harvested
must be kept under low temperatures. The cryopreservation also contributes to decrease the antigenic potential of the tissue.
Although this technique is considered safe, there is little information about the morphological modifications that the medullary
and cortical portions of bone suffer after freezing. Hence, the aim of this study was to investigate the morphology of bone
tissue after freezing under different temperatures and periods. Twelve rabbits were used to analyze the effects of two temperatures,
−20°C and −70°C, during four periods of time: 30, 60, 90, 120 days. Tissues were analyzed by HE, picro-sirius stains and also
by Feulgen’s reaction, through qualitative and morphometric ways, considering the area occupied by cells and nuclei, medullary
and cortical portions, as well as by collagen expression at cortical. The differences among the treatments were analyzed by
Tukey′s test, at 5% significance level. Bone freezing increased cellular and nuclear areas at cancellous bone and diminished
nuclear area at the cortical bone. Cortical bone collagen suffered denaturation proportionally to temperature decrease and
to freezing duration. These alterations compromised the morphology of tissues after 90 or 120 days of freezing at the temperature
of −70°C. Cells necrosed during freezing, contributing to reduce bone antigenicity. 相似文献
2.
Catherine S. Ford Nicky B. Jones Johannes van Staden 《In vitro cellular & developmental biology. Plant》2000,36(5):366-369
Summary The protocol currently used to cryopreserve Pinus patula embryogenic tissue was investigated in an attempt to improve and optimize the recovery of tissue. This investigation describes
two aspects that influence tissue recovery after cryopreservation: (i) the effects of precooling tissue prior to immersion
into liquid nitrogen; and (ii) whether the choice of supports onto which the recovered tissue is suspended improved the recovery
rate. Results indicated that precooling tissue to −70°C prior to immersion into liquid nitrogen was superior to precooling
to −30°C or direct immersion in liquid nitrogen (−196°C). Tissue recovery improved when polyester grids were used as supports,
and was slowest on filter paper supports. 相似文献
3.
Fifteen species of marine invertebrate commonly occurring in the near-shore environment of Rothera base, Antarctica, were
used to test tissue sample storage protocols with regard to preservation of RNA integrity. After animal collection, the tissues
were either immediately extracted for RNA or stored at −80°C after having been, either directly flash frozen in liquid nitrogen
or preserved in a commercial RNA storage solution, for extraction in the UK. In four cases, direct flash freezing produced
enhanced RNA integrity compared with samples in the commercial storage solution. A subset of samples were further tested for
the preferred temperature of storage in the commercial reagent. RNA integrity was well preserved at both +4 and −20°C over
periods of 2 months, but degradation was rapid in tissues stored at room temperature. Eight out of the fifteen species only
produced a single ribosomal band on gel electrophoresis. This survey provides a guide for tissue transport of Polar cold water
marine invertebrates. 相似文献
4.
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
5.
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
6.
Irina Kovalchuk Yelena Lyudvikova Mariam Volgina Barbara M. Reed 《Plant Cell, Tissue and Organ Culture》2009,96(2):127-136
The goal of this study was to evaluate the in vitro storage of apple germplasm by screening a range of genotypes followed
by more comprehensive testing of multiple parameters on two genotypes of differing species, Malus domestica cultivar Grushovka Vernenskaya and wild Malus sieversii selection TM-6. Stored plants were rated on a 6 point scale (0 low to 5 high) for plant appearance at 3 month intervals after
storage at 4°C. Combinations of carbon source (sucrose and/or mannitol), nitrate nitrogen content (25, 50 or 100%) and plant
growth regulators (ABA, BAP, IBA) were studied in three types of containers (tissue culture bags, test tubes or jars). An
initial screen of 16 genotypes stored in tissue culture bags indicated that plantlets could be stored at 4°C for 9–14 months
without subculture on standard 3% sucrose Murashige and Skoog (1962) (MS) medium with no plant growth regulators (PGRs). In subsequent in-depth studies on the two genotypes, ANOVA indicated
highly significant interactions of medium, container and genotype. ‘Grushovka Vernenskaya’ shoots with no PGRs and 3% sucrose
remained viable (ratings of ≥1) for 21 months of storage in bags. Storage on reduced nitrogen (MS with 25% nitrogen), PGRs,
and 3% sucrose kept ‘Grushovka Vernenskaya’ shoot condition rated >2 at 21 months. Addition of 0.5 or 1 mg−1 abscisic acid (ABA) also improved plant ratings at 21 months. The longest storage for ‘Grushovka Vernenskaya’ was 33–39 months
with PGRs and 3% sucrose in either tubes or jars. Addition of abscisic acid (ABA) to the medium did not improve storage of
plantlets in jars and tubes at 15 months. TM-6 stored best in tubes on 3% sucrose with PGRs or in jars on 2% mannitol and
2% sucrose. Overall it appears that cold storage of apple shoot cultures can be successful for 21 months in tissue culture
bags with 25% MS nitrate nitrogen, 3% sucrose, and no PGRs or for 33 months in jars or tubes on MS with 3% sucrose and PGRs.
Preliminary RAPD analysis found no significant differences between plants stored for 39 months and non-stored controls. 相似文献
7.
Summary The photosynthetic cell suspension culture of soybean [Glycine max (L.) Merr. cv. Corsoy] (SB-M) was successfully cryopreserved in liquid nitrogen using a preculture and controlled freezing
to −40° C (two-step) freezing method. The effective method included a preculture treatment with gradually increasing levels
of sorbitol added to the 3% sucrose already present in the medium. The cells were then placed in a cryoprotectant solution
[10% DMSO (dimethylsulfoxide) and 9.1% sorbitol, or 10% DMSO and 8% sucrose], incubated for 30 min at 0° C, cooled at a rate
of 1° C/min to −40° C, held at −40° C for 1 h, and then immersed directly into liquid nitrogen. The cells were thawed at 40°
C and then immediately placed in liquid culture medium. The cell viabilities immediately after thawing were 75% or higher
in all cases where cell growth resumed. The original growth rate and chlorophyll level of the cells was recovered within 40
to 47 d. If the sorbitol level was not high enough or the preculture period too short, growing cultures could not be recovered.
Likewise, survival was not attained with cryoprotectant mixtures consisting of 15% DMSO, 15% glycerol, and 9.1% sucrose or
15% glycerol and 8% sucrose. The successful method was reproducible, thus allowing long-term storage of this and certain other
unique photosynthetic suspension cultures in liquid nitrogen. 相似文献
8.
The main objective of this study was to evaluate the stability of astaxanthin after drying and storage at different conditions
during a 9-week period. Recovery of astaxanthin was evaluated by extracting pigments from the dried powders and analysing
extracts by HPLC. The powders obtained were stored under different conditions of temperature and oxygen level and the effects
on the degradation of astaxanthin were examined. Under the experimental conditions conducted in this study, the drying temperature
that yielded the highest content of astaxanthin was 220°C, as the inlet, and 120°C, as the outlet temperature of the drying
chamber. The best results were obtained for biomass dried at 180/110°C and stored at −21°C under nitrogen, with astaxanthin
degradation lower than 10% after 9 weeks of storage. A reasonable preservation of astaxanthin can be achieved by conditions
180/80°C, −21°C nitrogen, 180/110°C, 21°C nitrogen, and 220/80°C, 21°C vacuum: the ratio of astaxanthin degradation is equal
or inferior to 40%. In order to prevent astaxanthin degradation of Haematococcus pluvialis biomass, it is recommended the storage of the spray dried carotenized cells (180/110oC) under nitrogen and −21°C. 相似文献
9.
Determination of the kinetics of permeation of dimethyl sulfoxide in isolated corneas 总被引:2,自引:0,他引:2
Corneal cryopreservation requires that endothelial cells remain viable and intercellular structure be preserved. High viability
levels for cryopreserved endothelial cells have been achieved, but preserving intercellular structure, especially endothelial
attachment to Descemet's membrane, has proved difficult. Cell detachment apparently is not caused by ice, suggesting osmotic
or chemical mechanisms. Knowledge of the permeation kinetics of cryoprotectants (CPAs) into endothelial cells and stroma is
essential for controlling osmotic and chemical activity and achieving adequate tissue permeation prior to cooling. Proton
nuclear magnetic resonance (NMR) spectroscopy was used to assess the permeation of dimethyl sulfoxide (DMSO) into isolated
rabbit corneas. Corneas with intact epithelia were exposed to isotonic medium or 2.0 mol/L DMSO for 60 min and subsequently
transferred to 2.0 or 4.0 mol/L DMSO, respectively, at 22, 0, or −10°C. DMSO concentration in the cornea was measured vs time.
The Kedem-Katchalsky model was fitted to the data. Hydraulic permeability (m3/N·s) is 7.1×10−13+216%-11% at 22°C, 8.2×10−13+235%−21% at 0°C, and 1.7×10−14+19% −16% at −10°C. The reflection coefficient is 1.0+2%−1% at 22°C and 0°C, and 0.9±5% at −10°C. Solute mobility (cm/s) is
5.9×10−6+6%–11% at 22°C, 3.1×10−6+12%−11% at 0°C, and 5.0×10−8 cm/s+59%−40% at −10°C. 相似文献
10.
Amy E. Miller Joshua P. Schimel James O. Sickman Thomas Meixner Allen P. Doyle John M. Melack 《Biogeochemistry》2007,84(3):233-245
Cold-season processes are known to contribute substantially to annual carbon (C) and nitrogen (N) budgets in continental high
elevation and high-latitude soils, but their role in more temperate alpine ecosystems has seldom been characterized. We used
a 4-month lab incubation to describe temperature (−2, 0, 5°C) and moisture [50, 90% water-holding capacity (WHC)] effects
on soil C and N dynamics in two wet and one dry meadow soil from the Sierra Nevada, California. The soils varied in their
capacity to process N at and below 0°C. Only the dry meadow soil mineralized N at −2°C, but the wet meadow soils switched
from net N consumption at −2°C to net N mineralization at temperatures ≥0°C. When the latter soils were incubated at −2°C
at either moisture level (50 or 90% WHC), net NO3
− production decreased even as NH4
+ continued to accumulate. The same pattern occurred in saturated (90% WHC) soils at warmer temperatures (≥0°C), suggesting
that dissimilatory processes could control N cycling in these soils when they are frozen. 相似文献
11.
Fengjuan Zhao Ziguo Zhao Aihua Wang Jidong Liu Delin Duan 《Journal of applied phycology》2010,22(2):195-202
Morphological and culture studies of germlings derived from carpospores of Chrysymenia wrightii (Harvey) Yamada were carried out under various treatments combining temperature and irradiance. Basal, main, and tip branches
were applied for inducing callus-like tissue. Focus was on how carpospores develop into germlings, how callus-like tissues
are induced from explants, and how temperature and irradiance affect carpospore germination and discoid crust growth. Results
show that carpospore development can be divided into three stages: division stage, discoid crust stage, and erect juvenile
germling stage. Discoid crusts, even more than ten, might coalesce into a big discoid crust, and then developed into germlings.
Filamentous fronds, formed on the rims of discoid crusts, exhibited in self-existence or co-existence form with germlings,
could form spherical tufts if cultured separately. Filamentous callus-like tissues appeared on the tip branches after 13 days.
PES is suitable for filament induction and culture, and filaments have potential use in germplasm preservation and vegetative
propagation. Temperature (10, 15, 20, 25°C) and irradiance (8 and 36 μmol photons m−2 s−1) significantly influenced carpospore germination rate and discoid crust diameter. Carpospores germinated normally under 36 μmol
photons m−2 s−1, 15~25°C, and maximum growth of discoid crusts was at 25°C, 36 μmol photons m−2 s−1; 10°C and 8 μmol photons m−2 s−1 did not favor carpospore germination or discoid crust growth. 相似文献
12.
Michael M. Müller 《Plant and Soil》1987,102(2):185-191
The leaching of subterranean clover-derived N (15N) was investigated in a laboratory and a field experiment. In both experiments 30 cm i.d. ×50cm soil columns were used.
In the laboratory experiment the clover material was buried in the soil in mesh bags, and leaching of clover-derived N was
compared to leaching of added NH
4
+
−N and NO
3
−
−N over a period of 75 days at 20°C. During that time 75% of the clover-N was released from the mesh bags and 17% of the clover-N,
50% of the NH
4
+
−N and 70% of the NO
3
−
−N was leached through the soil column.
In the field experiment 6 lysimeters and 7 control microplots were constructed. The clover material was buried in soil (to
the soil of two control microplots within mesh bags) in October. During one year 2% of the added clover-N was leached. This
was despite a release of 65% of the N from the mesh bag contents and despite a 26% loss of the clover-derived N in total from
the controls. 相似文献
13.
Polar-desert plants experience low average air temperatures during their short growing season (4–8 °C mean July temperature).
In addition, low availability of inorganic nitrogen in the soil may also limit plant growth. Our goals were to elucidate which
N sources can be acquired by polar-desert plants, and how growth and N-uptake are affected by low growth temperatures. We
compared rates of N-uptake and increases in mass and leaf area of two polar-desert species (Cerastium alpinum L. and Saxifraga caespitosa L.) over a period of 3 weeks when grown at two temperatures (6 °C vs. 15 °C) and supplied with either glycine, NH4
+ or NO3
−. At 15 °C, plants at least doubled their leaf area, whereas there was no change in leaf area at 6 °C. Measured mean N-uptake
rates varied between 0.5 nmol g−1 root DM s−1 on glycine at 15 °C and 7.5 nmol g−1 root DM s−1 on NH4
+ at 15 °C. Uptake rates based upon increases in mass and tissue N concentrations showed that plants had a lower N-uptake rate
at 6 °C, regardless of N source or species. We conclude that these polar-desert plants can use all three N sources to increase
their leaf area and support flowering when grown at 15 °C. Based upon short-term (8 h) uptake experiments, we also conclude
that the short-term capacity to take up inorganic or organic N is not reduced by low temperature (6 °C). However, net N-uptake
integrated over a three-week period is severely reduced at 6 °C.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Cell density and fatty acid (FA) content of Pavlova lutheri and Chaetoceros muelleri were analysed in a continuous algal production system (250-L bags) with reduced diameter. The cell density and FA content
and composition in the algal production system were determined in replicate bags over a period of 5 weeks. The results showed
that the cell density and essential FAs increased during the experiment for both species. After 5 weeks the mean cell numbers
had increased to 6.0 ± 0.3 × 106 cells mL−1 in the P. lutheri bags and 6.0 ± 0.4 × 106 cells mL−1 in the C. muelleri bags. The content of total FAs increased significantly (p < 0.05) in all of the bags during the experiment. At the end of the experiment the mean total FA content were 2.7 ± 0.3 pg cell−1 in the P. lutheri bags and 1.8 ± 0.1 pg cell−1 in the C. muelleri bags. Maximum total FA content registered was 3.0 pg cell−1 in one of the P. lutheri bags. The content of the essential FAs (ARA, EPA, DHA) increased over time in both of the species. At the end of the experiment
the content of EPA (0.6 ± 0.1 pg cell−1) and DHA (0.3 ± 0.0 pg cell−1) were highest in the P. lutheri bags, while ARA (0.1 ± 0.0 pg cell−1) was highest in C. muelleri. EPA and DHA constituted 22% and 11%, respectively, of total FA content in P. lutheri, while ARA constituted 6% of total FA content in C. muelleri. The results from this experiment indicate that flagellates such as P. lutheri perform better in narrow bags with improved light conditions, while diatoms like C. muelleri perform better in wider bags under light limitation. Implications for bivalve hatcheries are discussed. 相似文献
15.
Christian Fölsch Andreas Kellotat Markus Rickert Bernd Ishaque Gafar Ahmed Axel Pruss Alexander Jahnke 《Cell and tissue banking》2016,17(3):427-437
Revision surgery of joint replacements is increasing and raises the demand for allograft bone since restoration of bone stock is crucial for longevity of implants. Proceedings of bone grafts influence the biological and mechanic properties differently. This study examines the effect of thermodisinfection on mechanic properties of cancellous bone. Bone cylinders from both femoral heads with length 45 mm were taken from twenty-three 6–8 months-old piglets, thermodisinfected at 82.5 °C according to bone bank guidelines and control remained native. The specimens were stored at ?20 °C immediately and were put into 21 °C Ringer’s solution for 3 h before testing. Shear and pressure modulus were tested since three point bending force was examined until destruction. Statistical analysis was done with non-parametric Wilcoxon, t test and SPSS since p < 0.05 was significant. Shear modulus was significantly reduced by thermodisinfection to 1.02 ± 0.31 GPa from 1.28 ± 0.68 GPa for unprocessed cancellous bone (p = 0.029) since thermodisinfection reduced pressure modulus not significantly from 6.30 ± 4.72 GPa for native specimens to 4.97 ± 2.23 GPa and maximum bending force was 270.03 ± 116.68 N for native and 228.80 ± 70.49 N for thermodisinfected cancellous bone. Shear and pressure modulus were reduced by thermodisinfection around 20 % and maximum bending force was impaired by about 15 % compared with native cancellous bone since only the reduction of shear modulus reached significance. The results suggest that thermodisinfection similarly affects different mechanic properties of cancellous bone and the reduction of mechanic properties should not relevantly impair clinical use of thermodisinfected cancellous bone. 相似文献
16.
The effect of polyunsaturated fatty acids on photosynthesis and the growth of the marine cyanobacterium Synechococcus sp. PCC 7002 was examined using wild-type and Δ12 fatty acid desaturase mutant strains. Under a light intensity of 250 μmol
m−2 s−1, wild-type cells could grow exponentially in a temperature range of 20–38 °C, but growth was non-exponential below 20 °C
and ceased at 12 °C. The Δ12 desaturase mutant cells lacking polyunsaturated fatty acids had the same growth rate as wild-type
cells in a temperature range of 25–38 °C but grew slowly at 22 °C, and no cell growth took place below 18 °C. Under a very
high-light intensity of 2.5 mmol m−2 s−1, wild-type cells could grow exponentially in a temperature range of 30–38 °C, although the high-light grown cells became
chlorotic because of nitrogen limitation. The temperature sensitive phenotype in the Δ12 desaturase mutant was enhanced in
cells grown under high-light illumination; the mutant cells could grow at 38 °C, but were killed at 30 °C. The decrease of
oxygen evolution and nitrate consumption by whole cells as a function of temperature was similar in both wild type and the
Δ12 desaturase mutant. No differences were observed in either light-induced damage of oxygen evolution or recovery from this
damage. No inactivation of oxygen evolution took place at 22 °C under the normal light intensity of 250 μmol m−2 s−1. These results suggest that growth of the Δ12 desaturase mutant at low temperature is not directly limited by the inactivation
of photosynthesis, and raise new questions about the functions of polyunsaturated membrane lipids on low temperature acclimation
in cyanobacteria.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
S. K. Schmidt D. R. Nemergut A. E. Miller K. R. Freeman A. J. King A. Seimon 《Extremophiles : life under extreme conditions》2009,13(5):807-816
High-elevation periglacial soils are among the most extreme soil systems on Earth and may be good analogs for the polar regions
of Mars where oligotrophic mineral soils abut with polar ice caps. Here we report on preliminary studies carried out during
an expedition to an area where recent glacial retreat has exposed porous mineral soils to extreme, daily freeze–thaw cycles
and high UV fluxes. We used in situ methods to show that inorganic nitrogen (NO3
− and NH4
+) was being actively cycled even during a period when diurnal soil temperatures (5 cm depth) ranged from −12 to 27°C and when
sub-zero, soil cooling rates reached 1.8°C h−1 (the most rapid soil cooling rates recorded to date). Furthermore, phylogenetic analyses of microbial phylotypes present
at our highest sites (5410 m above sea level) showed the presence of nitrifying bacteria of the genus Nitrospira and newly discovered nitrite-oxidizing Betaproteobacteria. These soils were overwhelmingly dominated (>70% of phylotypes)
by photosynthetic bacteria that were related to novel cyanobacteria previously found almost exclusively in other plant-free,
high-elevation soils. We also demonstrated that soils from our highest sites had higher potential for mineralizing glutamate
and higher microbial biomass than lower elevation soils that had been more recently covered by ice. Overall, our findings
indicate that a diverse and robustly functioning microbial ecosystem is present in these previously unstudied high-elevation
soils. 相似文献
18.
TheRhodotorula rubra strain isolated from waste waters of a gold mining plant has demonstrated the ability to grow in the presence of cyanide.
The maintenance of this strain in complex organic media leads to a loss of this ability. To preserve the cyanide resistance
ofR. rubra we tested the following maintenance methods: subculturing in sterile distilled water, freezing at −20, −40, −70°C, liquid
nitrogen freezing and the paper replica method. The ability to grow in the presence of cyanide was preserved and a higher
viability level was observed for cells maintained frozen at −70°C, in liquid nitrogen and by the paper replica method. Preservation
in distilled water resulted in the lowest viability after twelve months of storage. 相似文献
19.
The tissue bank “Rosa Guerzoni Chambergo” (RGCTB) located at the Child’s Health Institute was inaugurated in 1996, with the
financial and technical support of the IAEA program on radiation and tissue banking. Since 1998, the biological bandage of
fresh and lyophilised pigskin, amnion and bone tissue is processed routinely in this bank. In all cases, the tissue is sterilised
with the use of Cobalt-60 radiation, process carried out at the Laboratories of Irradiation of the Peruvian Institute of Nuclear
Energy (IPEN). The tissue bank in the Child’s Health Institute helped to save lives in an accident occurred in Lima, when
a New Year’s fireworks celebration ran out of control in January 2002. Nearly 300 people died in the tragic blaze and hundreds
more were seriously burned and injured. Eight Lima hospitals and clinics suddenly were faced with saving the lives of severely
burned men, women and children. Fortunately, authorities were ready to respond to the emergency. More than 1,600 dressings
were sterilised and supplied to Lima surgeons. The efforts helped save the lives of patients who otherwise might not have
survived the Lima fire. Between 1998 and September 2007, 35,012 tissue grafts were produced and irradiated. Radiation sterilised
tissues are used by 20 national medical institutions as well as 17 private health institutions. The tissue bank established
in Peru with the support of the IAEA is now producing the following tissues: pigskin dressings, fresh and freeze-dried; bone
allografts, chips, wedges and powdered, and amnion dressings air-dried. It is also now leading the elaboration of national
standards, assignment being entrusted by ONDT (Organización Nacional de Donación y Transplantes; National Organisation on
Donation and Transplant). This among other will permit the accreditation of the tissue bank. In this task is also participating
IPEN. 相似文献
20.
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