scholarly journals Variability of female gametophyte of tobacco in vivo and in vitro under the influence of extreme temperatures and its possible consequences

2020 ◽  
Author(s):  
L. P. Lobanova ◽  
A. Yu. Kolesova
Keyword(s):  
Low Temperatures ◽  
Female Gametophyte ◽  
Egg Cell ◽  
Extreme Temperatures ◽  
Abnormal Embryo ◽  
High And Low Temperatures

High and low temperatures induce the formation of abnormal embryo sacks (ES). ES with additional cells in the egg cell apparatus and synergids that are similar to an egg sells are capable of producing seeds with additional and haploid embrios.

scholarly journals Plant egg cell fate determination depends on its exact position in female gametophyte

2021 ◽  
Vol 118 (8) ◽  
pp. e2017488118 ◽  
Author(s):  
Yang Sun ◽  
Xiu Wang ◽  
Lin Pan ◽  
Fei Xie ◽  
Bo Dai ◽  
...  
Keyword(s):  
Cell Fate ◽  
Sperm Cell ◽  
Female Gametophyte ◽  
Imaging System ◽  
Egg Cell ◽  
Cell Identity ◽  
Auxin Level ◽  
Egg Apparatus

Plant fertilization involves both an egg cell, which fuses with a sperm cell, and synergid cells, which guide pollen tubes for sperm cell delivery. Therefore, egg and synergid cell functional specifications are prerequisites for successful fertilization. However, how the egg and synergid cells, referred to as the “egg apparatus,” derived from one mother cell develop into distinct cell types remains an unanswered question. In this report, we show that the final position of the nuclei in female gametophyte determines the cell fate of the egg apparatus. We established a live imaging system to visualize the dynamics of nuclear positioning and cell identity establishment in the female gametophyte. We observed that free nuclei should migrate to a specific position before egg apparatus specialization. Artificial changing in the nuclear position on disturbance of the actin cytoskeleton, either in vitro or in vivo, could reset the cell fate of the egg apparatus. We also found that nuclei of the same origin moved to different positions and then showed different cell identities, whereas nuclei of different origins moved to the same position showed the same cell identity, indicating that the final positions of the nuclei, rather than specific nucleus lineage, play critical roles in the egg apparatus specification. Furthermore, the active auxin level was higher in the egg cell than in synergid cells. Auxin transport inhibitor could decrease the auxin level in egg cells and impair egg cell identity, suggesting that directional and accurate auxin distribution likely acts as a positional cue for egg apparatus specialization.

Insight into AMPK regulation mechanism in vivo and in vitro: Responses to low temperatures in the olive flounder Paralichthys olivaceus

2020 ◽  
Vol 91 ◽  
pp. 102640
Author(s):  
Miaomiao Nie ◽  
Yunliang Lu ◽  
Congcong Zou ◽  
Lijuan Wang ◽  
Peijun Zhang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Paralichthys Olivaceus ◽  
Olive Flounder ◽  
Regulation Mechanism ◽  
Insight Into ◽  
Olive Flounder Paralichthys Olivaceus

Dependence of the Biological Activity of the Permafrost Bacteria Bacillus Sp. on Temperature

10.12737/7288 ◽  
2014 ◽  
Vol 21 (4) ◽  
pp. 142-148
Author(s):  
Субботин ◽  
A. Subbotin ◽  
Бажин ◽  
A. Bazhin ◽  
Калёнова ◽  
...  
Keyword(s):  
Biological Activity ◽  
Enzymatic Activity ◽  
Bacillus Cereus ◽  
Low Temperatures ◽  
Incubation Temperature ◽  
Probiotic Bacteria ◽  
Laboratory Animals ◽  
Bacillus Sp

Fossil bacteria in permafrost evolutionarily adapted to low temperatures (-5ºC), modern probiotics bacteria are adapted to living in warm-blooded animals (37ºC). It was found that at -5ºC, the enzymatic activity of fossil bacteria Bacillus sp. MG8 is a minimal strain. At lowering the incubation temperature to -16ºC, the enzymatic activity of bacte-ria MG8 increases in 3 times, at the temperature 42ºC - in a 1.5times relative IP5832 strain probiotic bacteria Bacillus cereus. Fossil strain Bacillus sp. MG8 and probiotic bacterial strain B.cereus IP5832 at incubation temperature 37ºC practically don’t differ from each other in the enzymatic activity in vitro and toxicity in laboratory animals in vivo. Incubation fossil bacteria Bacillus sp. at -5ºC allows to reduce their toxicity in warm-blooded animals in 5 times in comparison with Bacillus cereus JP5832, and to increase immunostimulating effect in the doses from 0,005•106 to 50•106 microbial cells per mouse. The obtained data show that fossil saprophytic bacteria strain MG8 Bacillus sp. from permafrost are less toxic to modern mammals than even bacilli-probiotics for medical purposes.

scholarly journals Dehydrins (LTI29, LTI30, COR47) from Arabidopsis thaliana expressed in Escherichia coli protect Thylakoid membrane during freezing

2013 ◽  
Vol 78 (8) ◽  
pp. 1149-1160 ◽  
Author(s):  
Vladan Bozovic ◽  
Jan Svensson ◽  
Jürgen Schmitt ◽  
Carsten Kohn
Keyword(s):  
Low Temperatures ◽  
Protein Concentration ◽  
Gene Families ◽  
Thylakoid Membranes ◽  
Protein Expression Level ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Mrna And Protein Expression

As the name dehydrins implies, these proteins are typically expressed in response to dehydration which can be caused by drought, osmotic stress or freezing temperatures 1. In general, dehydrins occur in plants as multi-gene families. Four Arabidopsis dehydrins (LTI29, ERD14, COR47 and RAB18) have been tested for protection of thylakoid membranes during freeze thaw cycle in vitro. 2,3 Our firstly reported results show that dehydrins LTI29, ERD14, COR47 have cryoprotective activity while RAB18 did not protect the thylakoid membranes at low temperatures. The cryoprotective activity reached a maximum of 50% to 60% at protein concentration of 140-250 ?g/ml in the assay. A contribution of dehydrins to freezing tolerance in vivo is supported by the observation of Nylander et al. (2001)4 that LTI29 and COR47 are cold induced at mRNA and protein expression level.

Selective Observation of Chlorophyll c in Whole Cells of Diatoms by Resonant Raman Spectroscopy

1986 ◽  
Vol 40 (2) ◽  
pp. 191-196 ◽  
Author(s):  
W.-D. Wagner ◽  
W. Waidelich
Keyword(s):  
Raman Spectra ◽  
Low Temperatures ◽  
Electronic Absorption Spectra ◽  
Chl A ◽  
Whole Cells ◽  
In Vitro Measurements ◽  
Sample Chamber ◽  
Resonant Raman

A surface scanning technique was used to obtain resonant Raman spectra from chlorophylls in solution and in whole cells of diatoms at 80 K. When in vivo samples are excited at 457.9 nm, chlorophyll c becomes observable in the recorded Raman spectra, as shown by comparison with in vitro measurements. In the field of photosynthetic research this becomes Interesting, as chlorophyll c can hardly be detected in electronic absorption spectra from whole cells, even at low temperatures, because of its weak Q bands compared with other plant chlorophylls. Chl a spectra were obtained with the use of 441.6-nm excitation. Working with two-channel recording, we eliminated the solvent contribution from the Raman spectra of pigments in vitro. Moreover, the technique facilitates detection of Raman excitation profiles from pigment lines in vivo at low temperatures by use of a nonresonating reference in the second sample chamber.

Resistance of faecal cysts of Spironucleus muris to some physical factors and chemical substances

1978 ◽  
Vol 12 (2) ◽  
pp. 95-97 ◽  
Author(s):  
I. Kunstýy̌ ◽  
E. Ammerpohl
Keyword(s):  
Osmotic Pressure ◽  
Chloride Solution ◽  
Room Temperature ◽  
Potassium Dichromate ◽  
Low Ph ◽  
Potassium Dichromate Solution ◽  
Physical Factors ◽  
High And Low Temperatures

The effect of 5 disinfectants, and of saturated zinc chloride solution + sodium chloride solution, 2·5% potassium dichromate solution, and 0·12% dimetridazole on faecal cysts of Spironuc1eus muris were tested in vitro. The resistance of the cysts to high and low temperatures, low pH, high osmotic pressure, centrifugation and desiccation was also tested. After treatment the morphology of the cysts was observed microscopically and their infectivity tested in vivo on sensitive thymus-deficient nude mice. The cysts ceased to be infective after treatment with most of usual distinfectants and by high temperature (45°C for 30 min). They resisted 0·12% dimetridazole, low temperature (-196°C), low pH (2·2), high osmotic pressure (distilled water and 30% 'Ficoll'), centrifugation (1500 g/20 min) and desiccation (room temperature for 14 days). These data may be useful for the control of Spironuc1eus muris infection in rodents and for cryopreservation of the parasite for experimental purposes.

scholarly journals Molecular Lesions Associated With Alleles of decapentuplegic Identify Residues Necessary for TGF-β/BMP Cell Signaling in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 493-505 ◽  
Author(s):  
Kristi Wharton ◽  
Robert P Ray ◽  
Seth D Findley ◽  
Holly E Duncan ◽  
William M Gelbart
Keyword(s):  
Cell Signaling ◽  
Low Temperatures ◽  
Point Mutations ◽  
Molecular Probes ◽  
Genetic Interactions ◽  
Temperature Sensitive ◽  
In Vitro Mutagenesis ◽  
Mutant Phenotypes

Abstract We have identified the molecular lesions associated with six point mutations in the Drosophila TGF-β homologue decapentaplegic (dpp). The sites of these mutations define residues within both the pro and ligand regions that are essential for dpp function in vivo. While all of these mutations affect residues that are highly conserved among TGF-β superfamily members, the phenotypic consequences of the different alleles are quite distinct. Through an analysis of these mutant phenotypes, both in cuticle preparations and with molecular probes, we have assessed the functional significance of specific residues that are conserved among the different members of the superfamily. In addition, we have tested for conditional genetic interactions between the different alleles. We show that two of the alleles are temperature sensitive for the embyronic functions of dpp, such that these alleles are not only embryonic viable as homozygotes but also partially complement other dpp hypomorphs at low temperatures. Our results are discussed with regard to in vitro mutagenesis data on other TGF-β-like molecules, as well as with regard to the regulation of dpp cell signaling in Drosophila.

scholarly journals FREEZING DYNAMICS 10% CALCIUM CHLORIDE SOLUTION WITH LIQUID NITROGEN IN VITRO

2018 ◽  
Vol 14 (3-4) ◽  
pp. 23-28
Author(s):  
O.I. Dronov ◽  
І.О. Kovalska ◽  
Ye.S. Kozachuk ◽  
N.Yu. Lukyanova ◽  
D.I. Khomenko ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Low Temperatures ◽  
Chloride Solution ◽  
Liquid Nitrogen Temperature ◽  
Original Design ◽  
The Mean ◽  
Temperature Indices ◽  
Pathological Focus

Relevance. Cryosurgical method is method of  ultra-low temperatures local  application for complete destruction of the pathological focus. Nowadays, question of cryosurgery  radicality remains unsolve, because of inability to achieve lethal for tumor cells temperatures  in  depth from cryoapplicator.That`s why, attempts of cryodestruction improving  are still keep going by developing methods of ultra-low temperatures cytodestructive effect  potentiation,  particulary, by their combination with chemical agents. Objective of the study was to determine the peculiarities of changes in temperature indices 10 % CaCl2 solution freezing in comparison with 0,9 % sodium chloride solution (0,9 % NaCl) in vitro. Materials and methods. Dynamic of low-temperatures changes were measured at control depths of 3, 8, 13, and 18 mm in 10% СаСl2 and 0.9% NaCl solutions by a four-channel measuring thermocouple complex KIIT-4. Cryo-tool of the original design was used for freezing. Cryoagent - liquid nitrogen (temperature -1800C). The temperature indices were detected during 10-minute exposure to liquid nitrogen. Results. During cryogenic exposure for 10 minutes at a distance of 13 and 18 mm from the cryoprobe, the mean temperatures in 10 % CaCl2 were significantly lower than 0,9 % NaCl (p <0,05). At control depths from 5th and 10th minute of exposure in 10 % CaCl2 the temperatures were significantly lower than 0,9 % NaCl (p <0,001). Conclusion. Consequently, 10 % CaCl2 can potentiate in vitro freezing processes and can be used to further improvemnt cryosurgery efficiency in vivo.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

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