The ultrastructure of quiescent buds of Tilia europaea

Shoot apices from quiescent axillary buds of the European linden tree were collected at three periods during the winter and prepared for electron microscopy by freeze-fracturing without pretreatment (i.e., no chemical fixation or glycerol infiltration). Cell structures were well preserved and not damaged by ice crystal formation. Tissue fine structure was comparable with other winter-quiescent tissues (particularly cambia) and showed the following characteristics: plentiful oil droplets, smaller quantities of other storage materials (protein, starch), inactive dictyosomes, and unusual arrangements of endoplasmic reticula (particularly a peripheral reticulum). Oil droplets were not bounded by a membrane. The quantity of oil (by cytoplasmic volume) declined steadily through the winter, presumably fuelling metabolic activity. The relatively flaccid condition of plasma membranes indicated that osmotic pressure was similar inside and outside the cells. Membrane-particle partition coefficients (Kp) between plasma membrane fracture moieties was unusual (< 1), and the significance of this observation in relation to cold acclimatisation is discussed. The appearance of the mouths (neck constrictions) of plasmodesmata changed between midwinter (closed) and early spring (open) and the observations are interpreted to indicate dynamic changes in a sphincter controlling intercellular exchange.

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High-pressure freezing and freeze substitution of plant tissue

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124148 ◽

1992 ◽

Vol 50 (1) ◽

pp. 748-749

Author(s):

William P. Sharp ◽

Robert W. Roberson

Keyword(s):

High Pressure ◽

Cell Structure ◽

Leaf Tissue ◽

Freeze Substitution ◽

Crystal Formation ◽

Ice Crystal ◽

High Pressure Freezing ◽

Cell Components ◽

Cold Metal ◽

Brome Grass

The aim of ultrastructural investigation is to analyze cell architecture and relate a functional role(s) to cell components. It is known that aqueous chemical fixation requires seconds to minutes to penetrate and stabilize cell structure which may result in structural artifacts. The use of ultralow temperatures to fix and prepare specimens, however, leads to a much improved preservation of the cell’s living state. A critical limitation of conventional cryofixation methods (i.e., propane-jet freezing, cold-metal slamming, plunge-freezing) is that only a 10 to 40 μm thick surface layer of cells can be frozen without distorting ice crystal formation. This problem can be allayed by freezing samples under about 2100 bar of hydrostatic pressure which suppresses the formation of ice nuclei and their rate of growth. Thus, 0.6 mm thick samples with a total volume of 1 mm3 can be frozen without ice crystal damage. The purpose of this study is to describe the cellular details and identify potential artifacts in root tissue of barley (Hordeum vulgari L.) and leaf tissue of brome grass (Bromus mollis L.) fixed and prepared by high-pressure freezing (HPF) and freeze substitution (FS) techniques.

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The “KIMWIPE” Effect in Ultra-Thin Cryosections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119119 ◽

1985 ◽

Vol 43 ◽

pp. 458-459

Author(s):

I. Taylor ◽

P. Ingram ◽

J.R. Sommer

Keyword(s):

Skeletal Muscle ◽

Electrical Stimulation ◽

Muscle Fibers ◽

Ice Crystals ◽

Crystal Formation ◽

Ice Crystal ◽

Thin Sections ◽

Skeletal Muscle Fibers ◽

Freeze Dried ◽

Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

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Water migration, ice crystal formation, and freeze-thaw stability of silver carp surimi as affected by inulin under different additive amounts and polymerization degrees

Food Hydrocolloids ◽

10.1016/j.foodhyd.2021.107267 ◽

2021 ◽

pp. 107267

Author(s):

Yuan Cao ◽

Liyuan Zhao ◽

Qilin Huang ◽

Shanbai Xiong ◽

Tao Yin ◽

...

Keyword(s):

Silver Carp ◽

Crystal Formation ◽

Water Migration ◽

Ice Crystal ◽

Freeze Thaw ◽

Ice Crystal Formation

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Atmospheric models improve understanding of ice-crystal formation

Physics Today ◽

10.1063/pt.5.026213 ◽

2012 ◽

Keyword(s):

Crystal Formation ◽

Ice Crystal ◽

Atmospheric Models ◽

Ice Crystal Formation

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57 THE EFFECT OF VITRIFICATION FOR SHEEP EMBRYO VIABILITY

Reproduction Fertility and Development ◽

10.1071/rdv27n1ab57 ◽

2015 ◽

Vol 27 (1) ◽

pp. 121

Author(s):

G. A. Valieva ◽

M. M. Toishibekov ◽

S. M. Askarov ◽

B. B. Molzhigitov

Keyword(s):

Developmental Competence ◽

Embryo Cryopreservation ◽

Crystal Formation ◽

Ice Crystal ◽

Embryo Viability ◽

Fresh Frozen ◽

Loop Volume ◽

Student’S T ◽

Phosphate Buffered Saline ◽

Student’S T Test

This work evaluated different methods for sheep embryo cryopreservation by vitrification (V) and super-cooling ultra-rapid vitrification (SCURV). The vitrification method was applied according to the method described by Vajta et al. Both treatments used a vitrification solution (VS) containing 20% ethylene glycol, 20% dimethylsulfoxide (Me2SO), 0.5 mol L–1 sucrose in Dulbecco's phosphate buffered saline (DPBS) with 10% BSA. The super-cooled LN facilitates heat transmission between LN and the cryosolution interface, and this is efficient for bovine semen and blastocyst cryoconservation (Arav et al. 2002). By surgical flushing 25 super-stimulated ewes, 109 transferable morulae were harvested; 35 morulae were transferred fresh to synchronized recipients (control) and the others were cryopreserved by V (n = 36) or SCURV (n = 38), respectively, thawed or warmed, and transferred to recipients. Embryos were vitrified using the HSV Kit. They were first incubated in 50% VS for 2 min and then transferred for 30 s into 100% VS. Each embryo was loaded by HSV Kit, which was immediately submerged into and stored in LN. Warming was done by placing the narrow end of the straw into DPBS + 0.25 M sucrose for 5 min. Embryos were then transferred into DPBS + 0.125 M sucrose for 3 min and finally to DPBS until transfer. The SCURV morulae were then exposed to 50 and 100% VS at 37°C for 2 min and 30 s, respectively. Embryos after saturation in VS were transferred on a surface of a nylon loop (volume 20 μL, diameter 0.5 mm) and using negative pressure of LN in the chamber for freezing with the VIT-Master. Thawing vitrified embryos was accomplished by placing the vitrified embryos in solutions of sucrose 0.25 M and 0.125 M with expositions 2 and 3 min accordingly. After thawing embryos, only good-quality embryos were transferred. Statistical analyses were performed with Student's t-test. The lambing rate following transfer of fresh, frozen-thawed vitrification and SCURV methods were 18, 12, 14 lambs accordingly. No statistical difference was found for the percentage of does lambing following transfer thawed after vitrification (33.4 ± 5.2a%) and SCURV methods (36.8 ± 6.3b%). The survival rate following transfer of fresh embryos (51.4 ± 4.8c) was higher and in line with previous findings using VS. Differences were statistically significant (ac,bc P < 0.05). Importantly, our data suggest that the HSV Kit can be used to produce viable morulae for implantation as the SCURV, and to as vitrification method. Although further work on the developmental competence of embryos cryopreserved with the SCURV method are needed, these data suggest that with SCURV a faster freeze rate and lower level of cryoprotectants is able to minimize ice crystal formation and should be further evaluated as a routine mechanism for cryopreserving sheep embryos.

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Crystal-plane-dependent effects of antifreeze glycoprotein impurity for ice growth dynamics

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2018.0393 ◽

2019 ◽

Vol 377 (2146) ◽

pp. 20180393 ◽

Cited By ~ 1

Author(s):

Yoshinori Furukawa ◽

Ken Nagashima ◽

Shunichi Nakatsubo ◽

Salvador Zepeda ◽

Ken-ichiro Murata ◽

...

Keyword(s):

Crystal Growth ◽

Growth Rates ◽

Space Station ◽

Supercooled Water ◽

Normal Growth ◽

Crystal Plane ◽

Impurity Effect ◽

Crystal Formation ◽

Ice Crystal ◽

Antifreeze Glycoprotein

An impurity effect on ice crystal growth in supercooled water is an important subject in relation to ice crystal formation in various conditions in the Earth's cryosphere regions. In this review, we consider antifreeze glycoprotein molecules as an impurity. These molecules are well known as functional molecules for controlling ice crystal growth by their adsorption on growing ice/water interfaces. Experiments on free growth of ice crystals in supercooled water containing an antifreeze protein were conducted on the ground and in the International Space Station, and the normal growth rates for the main crystallographic faces of ice, namely, basal and prismatic faces, were precisely measured as functions of growth conditions and time. The crystal-plane-dependent functions of AFGP molecules for ice crystal growth were clearly shown. Based on the magnitude relationship for normal growth rates among basal, prismatic and pyramidal faces, we explain the formation of a dodecahedral external shape of an ice crystal in relation to the key principle governing the growth of polyhedral crystals. Finally, we emphasize that the crystal-plane dependence of the function of antifreeze proteins on ice crystal growth relates to the freezing prevention of living organisms in sub-zero temperature conditions. This article is part of the theme issue ‘The physics and chemistry of ice: scaffolding across scales, from the viability of life to the formation of planets’.

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Single particle analysis of ice crystal residuals observed in orographic wave clouds over Scandinavia during INTACC experiment

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-1977-2006 ◽

2006 ◽

Vol 6 (7) ◽

pp. 1977-1990 ◽

Cited By ~ 61

Author(s):

A. C. Targino ◽

R. Krejci ◽

K. J. Noone ◽

P. Glantz

Keyword(s):

Elemental Composition ◽

Organic Material ◽

Mineral Dust ◽

Hierarchical Cluster ◽

Sea Salt ◽

Particle Analysis ◽

Crystal Formation ◽

Strong Impact ◽

Ice Crystal ◽

Orographic Clouds

Abstract. Individual ice crystal residual particles collected over Scandinavia during the INTACC (INTeraction of Aerosol and Cold Clouds) experiment in October 1999 were analyzed by Scanning Electron Microscopy (SEM) equipped with Energy-Dispersive X-ray Analysis (EDX). Samples were collected onboard the British Met Office Hercules C-130 aircraft using a Counterflow Virtual Impactor (CVI). This study is based on six samples collected in orographic clouds. The main aim of this study is to characterize cloud residual elemental composition in conditions affected by different airmasses. In total 609 particles larger than 0.1 μm diameter were analyzed and their elemental composition and morphology were determined. Thereafter a hierarchical cluster analysis was performed on the signal detected with SEM-EDX in order to identify the major particle classes and their abundance. A cluster containing mineral dust, represented by aluminosilicates, Fe-rich and Si-rich particles, was the dominating class of particles, accounting for about 57.5% of the particles analyzed, followed by low-Z particles, 23.3% (presumably organic material) and sea salt (6.7%). Sulfur was detected often across all groups, indicating ageing and in-cloud processing of particles. A detailed inspection of samples individually unveiled a relationship between ice crystal residual composition and airmass origin. Cloud residual samples from clean airmasses (that is, trajectories confined to the Atlantic and Arctic Oceans and/or with source altitude in the free troposphere) were dominated primarily by low-Z and sea salt particles, while continentally-influenced airmasses (with trajectories that originated or traveled over continental areas and with source altitude in the continental boundary layer) contained mainly mineral dust residuals. Comparison of residual composition for similar cloud ambient temperatures around –27°C revealed that supercooled clouds are more likely to persist in conditions where low-Z particles represent significant part of the analyzed cloud residual particles. This indicates that organic material may be poor ice nuclei, in contrast to polluted cases when ice crystal formation was observed at the same environmental conditions and when the cloud residual composition was dominated by mineral dust. The presented results suggest that the chemical composition of cloud nuclei and airmass origin have a strong impact on the ice formation through heterogeneous nucleation in supercooled clouds.

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