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1.
J Food Sci ; 85(1): 50-56, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31880331

RESUMO

The aim of this work was to study the influence of ι- and κ-carrageenan addition to strawberry sorbet prepared by various freezing methods (cryostat and conventional freezer) on freezing kinetics and ice crystals structure. Four variants of strawberry-based sorbet were prepared: with no additive, with 0.1% addition of ι- and κ-carrageenan, and 1:1 blend of both. Freezing curves and freezing time, as well as the size and morphology of ice crystals, were analyzed. The addition of carrageenan stabilizers resulted in freezing process elongation. Reference samples were characterized by different dynamics of the freezing process. The addition of carrageenan increased the final temperature of the samples, compared to the reference sample (even 2.6 °C of difference). Additives reduced ice crystals growth. The most efficient was mixture of both fractions of carrageenan--the samples in this variant frozen in conventional freezer were characterized by the smallest ice crystals diameter--average 5.44 µm, while for the reference sample it was 17.79 µm. PRACTICAL APPLICATION: This research can give a new path for the carrageenan's hydrolysates application--not only for dairy products. Iota carrageenan fraction was recommended for dairy products according to its water-holding capacity in the presence of calcium ions. This study showed that mix of ι- and κ-carrageenan could bring positive results to such product as sorbet without any milk proteins addition. This experiment data could also be helpful when optimizing frozen desserts production in small gastronomy--especially the temperature and time of freezing modifications.


Assuntos
Carragenina/análise , Aditivos Alimentares/análise , Fragaria/química , Frutas/química , Extratos Vegetais/química , Conservação de Alimentos/métodos , Congelamento , Gelo/análise , Temperatura Ambiente , Água/química
2.
Food Chem ; 306: 125641, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31606628

RESUMO

Temperature fluctuation is a common problem in the frozen storage of shrimp products. This study investigated the influence of carrageenan oligosaccharide (CO) and xylooligosaccharide (XO) on the growth and recrystallization of ice crystals in frozen peeled shrimp exposed to temperature fluctuations. Shrimp soaked with water and 3.0% (w/v) Na4P2O7 solution were designated as the negative and positive controls, respectively. Our data revealed that both CO- and XO-soaked shrimp had significant improvements in thawing and cooking loss, myofibrillar protein content, Ca2+-ATPase activity, and textural variables when exposed to temperature fluctuations compared to control samples. Microstructural imaging indicated that soaking the shrimp in CO and XO slowed the progression of damage caused to tissue myofibrils by large ice crystals, as well as inhibited the growth and recrystallization of ice crystals in muscle tissues. SDS-PAGE analysis confirmed that treatment with the oligosaccharides exhibited marked effects on the stability of muscle proteins and inhibited the degradation of muscle proteins affected by the temperature fluctuations. Based on these data, we hypothesize that the incorporated CO and XO may bind to muscle proteins and capture water molecules in the myofibrillar network through hydrogen bonding, thereby suppressing the myofibrillar denaturation and tissue structure destruction induced by the growth and recrystallization of ice crystals.


Assuntos
Carragenina/química , Glucuronatos/química , Oligossacarídeos/química , Penaeidae/química , Animais , Congelamento , Ligações de Hidrogênio , Gelo/análise , Temperatura Ambiente , Água/química
3.
Lett Appl Microbiol ; 69(4): 286-293, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392736

RESUMO

The prevalence of Listeria monocytogenes in the retail fish markets of the Kerala, India was investigated by screening 227 samples comprising of marine finfish (n = 97) shellfish (n = 19), ready-to-cook fish products (n = 47), ready-to-eat fish products (n = 10), dried fish (n = 11) and retail ice (n = 43). The prevalence of L. monocytogenes and L. innocua was 2·7% and 17·2% respectively. Sample category wise, prevalence of L. monocytogenes was higher in marine finfish (1·8%) and retail ice (0·9%). All the L. monocytogenes isolates carried virulent genes namely inlA, inlC, inlJ, hlyA, iap, plcA, prfA genes and majority (82%) belonged to 1/2a, 3a serogroups. L. monocytogenes isolates were multidrug-resistant and showed resistance to ampicillin, penicillin, erythromycin, tetracycline and clindamycin. Enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) delineated 58% genetic heterogeneity among the L. monocytogenes strains. The study reports that genetic similarities of the isolates were interlinked to their serogroup and sample origin. SIGNIFICANCE AND IMPACT OF THE STUDY: Prevalence of Listeria monocytogenes, in the retail fish markets of Kerala, India was low but their relatively higher presence in marine finfish and retail ice and virulent nature of the isolates signifies food safety concerns. Moreover, multidrug-resistant nature of these isolates may potentially lead to spread of antimicrobial resistance. This study identified retail ice as a vehicle for entry of L. monocytogenes in retail fish and hence, there is a need to ensure quality of retail ice used for maintaining the cold-chain.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Listeria monocytogenes/efeitos dos fármacos , Alimentos Marinhos/microbiologia , Frutos do Mar/microbiologia , Ampicilina/farmacologia , Animais , Clindamicina/farmacologia , Eritromicina/farmacologia , Pesqueiros , Peixes/microbiologia , Microbiologia de Alimentos , Inocuidade dos Alimentos , Heterogeneidade Genética , Gelo/análise , Índia , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Penicilinas/farmacologia , Prevalência , Sorogrupo , Tetraciclina/farmacologia
4.
Molecules ; 24(17)2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31461964

RESUMO

It is always difficult to assign the peaks of a vibrational spectrum in the far-infrared region. The two distinct peaks seen in many ice phases are still a mystery to date. The normal modes of ice XV were calculated using the CASTEP code based on first-principles density functional theory. On the basis of vibrational modes analysis, we divided the translational modes into three categories: four-bond vibrations, which have the highest energy levels; two-bond vibrations, which have medium levels of energy; and relative vibrations between two sublattices, which have the lowest energy. Whale et al. found that some intramolecular stretching modes include the isolated vibration of only one O-H bond, whereas the others do not vibrate in ice XV. We verified this phenomenon in this study and attributed it to local tetrahedral deformation. Analysis of normal modes, especially in the translation and stretching band of ice XV, clarified the physical insights of the vibrational spectrum and can be used with other ice phases.


Assuntos
Biologia Computacional/métodos , Gelo/análise , Algoritmos , Teoria da Densidade Funcional , Ligações de Hidrogênio , Estrutura Molecular , Vibração
5.
Molecules ; 24(17)2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31466370

RESUMO

The vibrational spectrum of ice II was investigated using the CASTEP code based on first-principles density functional theory (DFT). Based on good agreement with inelastic neutron scattering (INS), infrared (IR), and Raman experimental data, we discuss the translation, libration, bending, and stretching band using normal modes analysis method. In the translation band, we found that the four-bond and two-bond molecular vibration modes constitute three main peaks in accordance with INS ranging from 117 to 318 cm-1. We also discovered that the lower frequencies are cluster vibrations that may overlap with acoustic phonons. Whale et al. found in ice XV that some intramolecular vibrational modes include many isolated-molecule stretches of only one O-H bond, whereas the other O-H bond does not vibrate. This phenomenon is very common in ice II, and we attribute it to local tetrahedral deformation. The pathway of combining normal mode analysis with experimental spectra leads to scientific assignments.


Assuntos
Gelo/análise , Teoria da Densidade Funcional , Ligações de Hidrogênio , Estrutura Molecular , Vibração
6.
Acta Crystallogr F Struct Biol Commun ; 75(Pt 5): 377-384, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31045567

RESUMO

With better tools for data processing and with synchrotron beamlines that are capable of collecting data at longer wavelengths, sulfur-based native single-wavelength anomalous dispersion (SAD) phasing has become the `first-choice' method for de novo protein structure determination. However, for many proteins native SAD phasing can be simplified by taking advantage of their interactions with natural metal cofactors that are stronger anomalous scatterers than sulfur. This is demonstrated here for four unique domains of a 1.5 MDa calcium-dependent adhesion protein using the anomalous diffraction of the chelated calcium ions. In all cases, low anomalous multiplicity X-ray data were collected on a home-source diffractometer equipped with a chromium rotating anode (λ = 2.2909 Å). In all but one case, calcium SAD phasing alone was sufficient to allow automated model building and refinement of the protein model after the calcium substructure had been determined. Given that Ca atoms will be present in a significant percentage of proteins that remain uncharacterized, many aspects of the data-collection and processing methods described here could be broadly applied for routine de novo structure elucidation.


Assuntos
Adesinas Bacterianas/química , Proteínas de Bactérias/química , Cálcio/química , Gelo/análise , Marinomonas/química , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Sequência de Aminoácidos , Organismos Aquáticos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Cálcio/metabolismo , Cátions Bivalentes , Clonagem Molecular , Temperatura Baixa , Cristalografia por Raios X , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Difração de Raios X
7.
Environ Sci Technol ; 53(10): 5887-5894, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31070370

RESUMO

Measurement of elemental concentrations in ice cores are critical for determining atmospheric aerosol variations. For such measurements, acidified ice-core meltwater typically is analyzed continuously (<5 min after acidification) or discretely (∼3 months after acidification). The reduced acidification time during continuous analysis may result in a measured elemental concentration that is lower than the concentration of discrete analysis if particulates are not fully dissolved. To evaluate this, sections of three ice cores from Greenland and Antarctica were measured both continuously (4.5 min after acidification) and discretely (repeatedly from 1 to 151 days after continuous measurements), with discrete samples collected from the meltwater sample stream prior to continuous measurement. We show that elements such as Na, Sr, and S dissolved readily and therefore were fully recovered during continuous measurements. Average recovery for other elements was between 70 to 100% for Cd, Gd, Mg, Mn, U, and Yb, 50 to 90% for Ca, Ce, Sm, and V, and less than 50% for Al, Fe, and La. Given the advantages of continuous measurements, we conclude that the preferred method for ice-core measurements is continuous analysis with simultaneous discrete sample collection, followed by adjustment of the continuous measurements based on discrete sample analysis at least 3 months after acidification.


Assuntos
Gelo , Regiões Antárticas , Groenlândia , Gelo/análise , Íons
8.
Water Environ Res ; 91(5): 455-461, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30740828

RESUMO

Eutectic freeze crystallization was developed to recover sodium erythorbate (NaE) from wastewater at pHs 4.1, 5.3, and 6.5. Two substances (A and B) were sequentially recovered from the samples. The recovery rate of substance A was 2.06, 1.83, and 3.03 g/L at pHs 4.1, 5.3, and 6.5, respectively; while that of B was 5.51, 3.09, and 3.26 g/L at the corresponding pHs. The analysis results of the two recovered substances indicated that substance A was mostly Na2 SO4 ·10H2 O, while substance B was mainly NaE. Salt recovery was most successful at pH 4.1 with the purity of recovered NaE reaching 87.53 wt%. Moreover, the chemical oxygen demand and electric conductivity of the ice were far smaller than the initial wastewater. The concentration effect was minimal due to the formation of Na2 SO4 ·10H2 O and NaE crystals. This combined crystallization strategy can potentially become an economic technology to recover NaE from wastewater. Practitioner points Segregation of NaE and Na2 SO4 ·10H2 O during the freeze crystallization process. Recovering 5.53 kg NaE with the purity of 87.53 wt% from 1 m3 wastewater. Decreasing chemical oxygen demand and electric conductivity of wastewater through freeze crystallization technology.


Assuntos
Ácido Ascórbico/química , Ácido Ascórbico/isolamento & purificação , Congelamento , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Cristalização , Concentração de Íons de Hidrogênio , Gelo/análise , Fatores de Tempo
9.
Cryobiology ; 86: 47-51, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30597125

RESUMO

Devitrification has been determined to be one of the major causes of cell death in cryopreservation by vitrification method. Reliable quantification of the nucleation and growth of ice crystals of devitrification is of great importance for the optimization of the vitrification solutions. In the present study, cryomicroscopy was used to investigate the nucleation and growth of ice crystals in concentrated glycerol aqueous solution (60 wt%) in the presence of sucrose, trehalose, maltose and lactose. Results showed that sucrose rather than trehalose seems to be the most effective one to inhibit the nucleation and ice growth, despite the excellent inhibitory ability of trehalose on ice growth that has been confirmed in many researches. Hence, for ice inhibition, sucrose was a more effective disaccharide additive to suppress nucleation and growth of ice crystals that occurred during devitrification in concentrated glycerol solutions.


Assuntos
Crioprotetores/farmacologia , Glicerol/química , Lactose/química , Maltose/química , Sacarose/química , Trealose/química , Criopreservação/métodos , Gelo/análise , Vitrificação/efeitos dos fármacos , Água
10.
Food Chem ; 278: 452-459, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-30583396

RESUMO

Obscure pufferfish (Takifugu obscurus) softening during frozen storage remains to be solved. This study was therefore aimed to provide explanations by differentiate the roles of three potential factors in fish softening. The influences of ice crystal, endogenous proteolytic activities, and oxidization were distinguished by treatment of fish fillets with liquid nitrogen, iodoacetic acid, and tea polyphenol with ascorbic acid, respectively. This distinguishing method was verified to be effective by investigation in ice crystal microstructure, endogenous proteolytic activities and lipid and protein oxidation. In comparison of three factors, it showed that the shear force of fish fillets with smaller ice crystals was about 15.5% and 13.7% higher than those with the inhibition of endogenous proteolytic activities and oxidation respectively, indicating the dominant role of ice crystal in frozen fish softening. Besides, quality decline of frozen fish was initially fast and then slowed down during the storage.


Assuntos
Congelamento , Alimentos Marinhos/análise , Takifugu/metabolismo , Animais , Ácido Ascórbico/química , Cristalização , Gelo/análise , Ácido Iodoacético/química , Nitrogênio/química , Oxirredução , Peptídeo Hidrolases/química , Peptídeo Hidrolases/metabolismo , Polifenóis/química , Proteólise , Resistência ao Cisalhamento
11.
Food Chem ; 278: 482-490, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-30583401

RESUMO

Cryoprotective saccharides are widely accepted antifreeze additives that reduce thawing loss, maintain texture, and retard protein denaturation in frozen seafood. In this study, the inhibition effects of trehalose and alginate oligosaccharides on ice growth were investigated and compared with sodium pyrophosphate (Na4P2O7) treatment in peeled shrimp during frozen storage, especially the interactions between saccharide molecules and ice crystals. The microstructural results demonstrated that the pre-soaking of trehalose and alginate oligosaccharides before freezing exhibited marked effects on stability of muscle tissue structures and slowed the damage caused to the myofibrils by large ice crystals. The ice-growth inhibition activities might play an important role in cryoprotective effects of saccharides on frozen muscle tissue. Furthermore, molecular docking and molecular dynamics (MD) simulations proved that saccharides were generally close to the ice interface and embedded in ice layers via hydrogen bonds or hydrophobic or electrostatic interactions. The saccharides-ice complex was partially destroyed, and some dislocation and disaggregation were observed around the saccharides molecules. Thus, the incorporated saccharides suppressed the growth of ice crystals, providing protection from freeze-induced damage. Here, the obtained structural details of the ice crystals interface affected by trehalose and alginate oligosaccharides were well in agreement with the histological (H&E staining) experimental results. These findings help better understand the ice-growth inhibition mechanisms of saccharides in frozen shrimp, and these two saccharides may be potentially used as ice-growth inhibitors in frozen seafood.


Assuntos
Congelamento , Gelo/análise , Oligossacarídeos/química , Trealose/química , Alginatos/química , Animais , Difosfatos/química , Ligações de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Penaeidae/química , Eletricidade Estática
12.
PLoS One ; 13(12): e0208519, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30521619

RESUMO

Lakes are a key geographical feature in Canada and have an impact on the regional climate. In the winter, they are important for recreational activities such as snowmobiling and ice fishing and act as part of an important supply route for northern communities. The ability to accurately report lake ice characteristics such as thickness is vital, however, it is underreported in Canada and there is a lack of lake ice thickness records for temperate latitude areas such as Central Ontario. Here, we evaluate the application of previously developed temperature models and RADARSAT-2 for estimating lake ice thickness in Central Ontario and provide insight into the regions long term ice thickness variability. The ALS Environmental Science Shallow Water Ice Profiler (SWIP) was used for validation of both temperature and radar-based models. Results indicate that the traditional approach that uses temperatures to predict ice thickness during ice growth has low RMSE values of 2.3 cm and correlations of greater than 0.9. For ice decay, similar low RMSE values of 2.1 cm and high correlations of 0.97 were found. Using RADARSAT-2 to estimate ice thickness results in R2 values of 0.6 (p < 0.01) but high RMSE values of 11.7 cm. Uncertainty in the RADARSAT-2 approach may be linked to unexplored questions about scattering mechanisms and the interaction of radar signal with mid-latitude lake ice. The application of optimized temperature models to a long-term temperature record revealed a thinning of ice cover by 0.81 cm per decade.


Assuntos
Camada de Gelo , Gelo/análise , Clima , Lagos , Ontário , Radar
14.
Proc Natl Acad Sci U S A ; 115(48): 12136-12141, 2018 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-30420500

RESUMO

Iodine is an important nutrient and a significant sink of tropospheric ozone, a climate-forcing gas and air pollutant. Ozone interacts with seawater iodide, leading to volatile inorganic iodine release that likely represents the largest source of atmospheric iodine. Increasing ozone concentrations since the preindustrial period imply that iodine chemistry and its associated ozone destruction is now substantially more active. However, the lack of historical observations of ozone and iodine means that such estimates rely primarily on model calculations. Here we use seasonally resolved records from an Alpine ice core to investigate 20th century changes in atmospheric iodine. After carefully considering possible postdepositional changes in the ice core record, we conclude that iodine deposition over the Alps increased by at least a factor of 3 from 1950 to the 1990s in the summer months, with smaller increases during the winter months. We reproduce these general trends using a chemical transport model and show that they are due to increased oceanic iodine emissions, coupled to a change in iodine speciation over Europe from enhanced nitrogen oxide emissions. The model underestimates the increase in iodine deposition by a factor of 2, however, which may be due to an underestimate in the 20th century ozone increase. Our results suggest that iodine's impact on the Northern Hemisphere atmosphere accelerated over the 20th century and show a coupling between anthropogenic pollution and the availability of iodine as an essential nutrient to the terrestrial biosphere.


Assuntos
Poluentes Atmosféricos/química , Gelo/análise , Iodo/química , Água do Mar/química , Atmosfera , Clima , Europa (Continente) , Ozônio/química , Estações do Ano
15.
Adv Exp Med Biol ; 1081: 99-115, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30288706

RESUMO

Control of freezing in plant tissues is a key issue in cold hardiness mechanisms. Yet freeze-regulation mechanisms remain mostly unexplored. Among them, ice nucleation activity (INA) is a primary factor involved in the initiation and regulation of freezing events in plant tissues, yet the details remain poorly understood. To address this, we developed a highly reproducible assay for determining plant tissue INA and noninvasive freeze visualization tools using MRI and infrared thermography. The results of visualization studies on plant freezing behaviors and INA survey of over 600 species tissues show that (1) freezing-sensitive plants tend to have low INA in their tissues (thus tend to transiently supercool), while wintering cold-hardy species have high INA in some specialized tissues; and (2) the high INA in cold-hardy tissues likely functions as a freezing sensor to initiate freezing at warm subzero temperatures at appropriate locations and timing, resulting in the induction of tissue-/species-specific freezing behaviors (e.g., extracellular freezing, extraorgan freezing) and the freezing order among tissues: from the primary freeze to the last tissue remaining unfrozen (likely INA level dependent). The spatiotemporal distributions of tissue INA, their characterization, and functional roles are detailed. INA assay principles, anti-nucleation activity (ANA), and freeze visualization tools are also described.


Assuntos
Aclimatação , Bioensaio/métodos , Congelamento , Gelo/análise , Plantas/metabolismo , Resposta ao Choque Frio , Raios Infravermelhos , Imagem por Ressonância Magnética , Plantas/química , Transdução de Sinais , Especificidade da Espécie , Termografia/métodos
16.
Adv Exp Med Biol ; 1081: 117-127, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30288707

RESUMO

Since the discovery of infrared radiation in 1800, the improvement of technology to detect and image infrared (IR) has led to numerous breakthroughs in several scientific fields of study. The principle that heat is released when water freezes and the ability to image this release of heat using IR thermography (IRT) has allowed an unprecedented understanding of freezing in plants. Since the first published report of the use of IRT to study freezing in plants, numerous informative discoveries have been reported. Examples include barriers to freezing, specific sites of ice nucleation, direction and speed of ice propagation, specific structures that supercool, and temperatures at which they finally freeze. These and other observations underscore the significance of this important technology on plant research.


Assuntos
Aclimatação , Congelamento , Gelo/análise , Raios Infravermelhos , Plantas/metabolismo , Termografia/métodos , Resposta ao Choque Frio , Plantas/química , Transdução de Sinais , Especificidade da Espécie
17.
Adv Exp Med Biol ; 1081: 289-320, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30288716

RESUMO

Studies on supercooling-promoting substances (SCPSs) are reviewed introducing name of chemicals, experimental conditions and the supercooling capability (SCC) in all, so far recognized, reported SCPSs and results of our original study are presented in order to totally show the functional properties of SCPSs which are known in the present state. Many kinds of substances have been identified as SCPSs that promote supercooling of aqueous solutions in a non-colligative manner by reducing the ice nucleation capability (INC) of ice nucleators (INs). The SCC as revealed by reduction of freezing temperature (°C) by SCPSs differs greatly depending on the INs. While no single SCPS that affects homogeneous ice nucleation to reduce ice nucleation point has been found, many SCPSs have been found to reduce freezing temperatures by heterogeneous ice nucleation with a large fluctuation of SCC depending on the kind of heterogeneous IN. Not only SCPSs increase the degree of SCC (°C), but also some SCPSs have additional SCC to stabilize a supercooling state for a long term to stabilize supercooling against strong mechanical disturbance and to reduce sublimation of ice crystals. The mechanisms underlying the diverse functions of SCPSs remain to be determined in future studies.


Assuntos
Proteínas Anticongelantes/química , Crioprotetores/química , Congelamento , Gelo/análise , Cristalização , Modelos Químicos
18.
Adv Exp Med Biol ; 1081: 321-337, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30288717

RESUMO

Numerous embryonic ice crystals are generated in water at the moment of freezing. These crystals grow and merge together to form an ice block that can be generally observed. Antifreeze protein (AFP) is capable of binding to the embryonic ice crystals, inhibiting such an ice block formation. Fish-derived AFP additionally binds to membrane lipid bilayers to prolong the lifetime of cells. These unique abilities of AFP have been studied extensively for the development of advanced techniques, such as ice recrystallization inhibitors, freeze-tolerant gels, cell preservation fluids, and high-porosity ceramics, for which mass-preparation method of the quality product of AFP utilizing fish muscle homogenates made a significant contribution. In this chapter, we present both fundamental and advanced information of fish AFPs that have been especially discovered from mid-latitude sea area, which will provide a hint to develop more advanced techniques applicable in both medical and industrial fields.


Assuntos
Proteínas Anticongelantes/farmacologia , Criopreservação/métodos , Crioprotetores/farmacologia , Proteínas de Peixes/farmacologia , Congelamento , Gelo/análise , Animais , Proteínas Anticongelantes/química , Proteínas Anticongelantes/isolamento & purificação , Crioprotetores/química , Crioprotetores/isolamento & purificação , Cristalização , Proteínas de Peixes/química , Proteínas de Peixes/isolamento & purificação , Humanos , Japão , Relação Estrutura-Atividade
19.
Adv Exp Med Biol ; 1081: 339-354, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30288718

RESUMO

Cryopreservation involves the preservation of biological materials, including cells, embryos, tissues, and organs, at ultra-low temperatures (in a state of suspended animation), for a long period of time, and in a way that allows them to be restored whenever required. Freezing of biological samples is generally accompanied by numerous undesirable outcomes such as intra- and extracellular freezing damage and osmotic stress. To prevent these adverse effects, cryoprotective agents (CPAs) are added to biological materials before freezing. Over the years, a number of CPAs have been identified and developed and have been employed successfully for numerous applications. Here, we review the history and development of cryoprotectants and the current understanding of the cryopreservation process. We conclude with a discussion about the application of cryopreservation for various clinical and academic studies.


Assuntos
Criopreservação/métodos , Crioprotetores/farmacologia , Congelamento , Gelo/análise , Animais , Crioprotetores/química , Cristalização , Embrião de Mamíferos , Humanos , Masculino , Oócitos , Preservação do Sêmen/métodos , Espermatozoides , Engenharia Tecidual/métodos
20.
Adv Exp Med Biol ; 1081: 355-369, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30288719

RESUMO

Cryopreservation encompasses several interconnect disciplines including physiology and cryophysics. This chapter reviews the current techniques for cryopreservation of plant genetic resources (PGRs). Vitrification is an effective ice crystal avoidance mechanism for hydrated cells and tissues. With any cryopreservation method, whole or partial parts of specimens which are sufficiently dehydrated can be vitrified by rapid cooling in liquid nitrogen (LN). Techniques discussed are the vitrification protocol, encapsulation-vitrification protocol, droplet vitrification protocol (DV), vitrification protocol using cryo-plates (V cryo-plate), and air dehydration protocol using cryo-plates (D cryo-plate). In these DV, V, and D cryo-plate protocols, specimens to be cryopreserved are immersed directly into LN on aluminum foil strips or cryo-plates; removal from LN to rewarming solution results in a high level of plant regrowth with ultrarapid cooling and warming. The protocols were applied to a wide array of plant species including wild and multi-ploid species, although fine tuning of the protocols was required for successful application to specific plant species and lines. These three protocols efficiently complement each other and appear highly promising to facilitate large-scale cryobanking of PGRs in genebanks. Cryo-scanning electron microscopy makes it possible to examine the cellular and water behavior in plant tissues when immersed in LN. It has been verified that tissues cryopreserved by the process of vitrification and the cryo-plate protocols are cryopreservation methods for reliable long-term preservation of PGRs.


Assuntos
Criopreservação/métodos , Congelamento , Genes de Plantas , Plantas/genética , Cristalização , Regulação da Expressão Gênica de Plantas , Gelo/análise , Desenvolvimento Vegetal/genética , Plantas/ultraestrutura , Vitrificação
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