Cytogenetic abnormalities of cotton somaclones from callus cultures

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 762-770 ◽  
Author(s):  
David M. Stelly ◽  
D. W. Altman ◽  
R. J. Kohel ◽  
T. S. Rangan ◽  
E. Commiskey
Keyword(s):  
Cell Culture ◽  
Tissue Culture ◽  
Somaclonal Variation ◽  
High Frequency ◽  
Chromosomal Abnormalities ◽  
Callus Cultures ◽  
Meiotic Abnormalities ◽  
High Frequencies ◽  
Field Environment ◽  
Metaphase I

Somaclonal variation occurs among regenerants from tissue culture of many plant species. Our objective was to determine whether cytogenetic variation contributes to somaclonal variation in cotton (Gossyptum hirsutum L.,2n = 4x = 52). Of 117 somaclones of cotton regenerated from 18-month-old callus cultures of 'SJ-2' and 'SJ-5' cultivars, 35 were analyzed for meiotic abnormalities. The population of somaclones was extremely varied in phenotype, most plants being strikingly aberrant in phenotype. Fertility was generally poor: 84% failed to set bolls and only 5% set 10 or more bolls in a field environment. Only one of the somaclones (3%) formed 26 bivalents at metaphase I. Fourteen were nonsynaptic to partially synaptic at metaphase I. Synaptic abnormalities impaired fertility and precluded thorough metaphase analysis. Chromosome numbers obtained for 32 plants ranged from 49 to 53, and only 1 plant was hyperaneuploid. No plant was polyploid. Chromosomal abnormalities in plants with normal metaphase pairing included univalents, unequal bivalents, rod bivalents, trivalents, open quadrivalents, and centric fragments. Seventeen hypoaneuploid plants formed a V-shaped trivalent at metaphase I, constituting a high frequency of tertiary monosomy. The high frequencies of aneuploidy and tertiary monosomy indicate that cytogenetic anomalies are a major source of somaclonal variation in cotton. It is hypothesized that (i) primary cytogenetic events during cotton cell culture give rise to breakage – fusion – bridge (BFB) cycles, (ii) BFB cycles accrue during culture, (iii) BFB cycles cause loss of chromatin, and (iv) BFB cycles are resolved by the formation of stable tertiary chromosomes with mono-centric activity. The hypothesis accounts mechanistically for the coincidence of chromatin deficiencies and chromatin exchange involved implicitly in tertiary monosomy, as well as for the relatively high frequency of tertiary monosomy among somaclones.Key words: aneuploid, monosomic, synaptic, sterility, Gossypium.

scholarly journals Rheology of rounded mammalian cells over continuous high-frequencies

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gotthold Fläschner ◽  
Cosmin I. Roman ◽  
Nico Strohmeyer ◽  
David Martinez-Martin ◽  
Daniel J. Müller
Keyword(s):  
High Frequency ◽  
Mammalian Cells ◽  
Mechanical Response ◽  
Cell Mass ◽  
Low Frequency ◽  
Mass Measurements ◽  
High Frequencies ◽  
Polymer Relaxation ◽  
Continuous Frequency ◽  
Rheological Experiments

AbstractUnderstanding the viscoelastic properties of living cells and their relation to cell state and morphology remains challenging. Low-frequency mechanical perturbations have contributed considerably to the understanding, yet higher frequencies promise to elucidate the link between cellular and molecular properties, such as polymer relaxation and monomer reaction kinetics. Here, we introduce an assay, that uses an actuated microcantilever to confine a single, rounded cell on a second microcantilever, which measures the cell mechanical response across a continuous frequency range ≈ 1–40 kHz. Cell mass measurements and optical microscopy are co-implemented. The fast, high-frequency measurements are applied to rheologically monitor cellular stiffening. We find that the rheology of rounded HeLa cells obeys a cytoskeleton-dependent power-law, similar to spread cells. Cell size and viscoelasticity are uncorrelated, which contrasts an assumption based on the Laplace law. Together with the presented theory of mechanical de-embedding, our assay is generally applicable to other rheological experiments.

scholarly journals Tribological, biocompatibility, and antibiofilm properties of tungsten–germanium coating using magnetron sputtering

2021 ◽  
Vol 32 (1) ◽  
Author(s):  
Mustafa Şükrü Kurt ◽  
Mehmet Enes Arslan ◽  
Ayşenur Yazici ◽  
İlkan Mudu ◽  
Elif Arslan
Keyword(s):  
Cell Culture ◽  
Magnetron Sputtering ◽  
Cell Line ◽  
Borosilicate Glass ◽  
Chromosomal Abnormalities ◽  
Dermal Fibroblast ◽  
Fibroblast Cell ◽  
Antibiofilm Activity ◽  
Borosilicate Glasses

AbstractIn this study, borosilicate glass and 316 L stainless steel were coated with germanium (Ge) and tungsten (W) metals using the Magnetron Sputtering System. Surface structural, mechanical, and tribological properties of uncoated and coated samples were examined using SEM, X-ray diffraction (XRD), energy-dispersive spectroscopy, and tribometer. The XRD results showed that WGe2 chemical compound observed in (110) crystalline phase and exhibited a dense structure. According to the tribological analyses, the adhesion strength of the coated deposition on 316 L was obtained 32.8 N, and the mean coefficient of friction was around 0.3. Biocompatibility studies of coated metallic biomaterials were analyzed on fibroblast cell culture (Primary Dermal Fibroblast; Normal, Human, Adult (HDFa)) in vitro. Hoescht 33258 fluorescent staining was performed to investigate the cellular density and chromosomal abnormalities of the HDFa cell line on the borosilicate glasses coated with germanium–tungsten (W–Ge). Cell viabilities of HDFa cell line on each surface (W–Ge coated borosilicate glass, uncoated borosilicate glass, and cell culture plate surface) were analyzed by using (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cytotoxicity assay. The antibiofilm activity of W–Ge coated borosilicate glass showed a significant reduction effect on Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) adherence compared to control groups. In the light of findings, tungsten and germanium, which are some of the most common industrial materials, were investigated as biocompatible and antimicrobial surface coatings and recommended as bio-implant materials for the first time.

scholarly journals RAG-Mediated V(D)J Recombination Is Not Essential for Tumorigenesis in Atm-Deficient Mice

2002 ◽  
Vol 22 (9) ◽  
pp. 3174-3177 ◽  
Author(s):  
Lisa K. Petiniot ◽  
Zoë Weaver ◽  
Melanie Vacchio ◽  
Rhuna Shen ◽  
Danny Wangsa ◽  
...  
Keyword(s):  
High Frequency ◽  
Chromosomal Abnormalities ◽  
Chromosomal Translocations ◽  
Thymic Lymphoma ◽  
Double Stranded Dna ◽  
Break Repair ◽  
Rag 1 ◽  
Deficient Mice

ABSTRACT Atm-deficient mice die of malignant thymic lymphomas characterized by translocations within the Tcrα/δ locus, suggesting that tumorigenesis is secondary to aberrant responses to double-stranded DNA (dsDNA) breaks that occur during RAG-dependent V(D)J recombination. We recently demonstrated that development of thymic lymphoma in Atm−/− mice was not prevented by loss of RAG-2. Thymic lymphomas that developed in Rag2−/− Atm−/− mice contained multiple chromosomal abnormalities, but none of these involved the Tcrα/δ locus. These findings indicated that tumorigenesis in Atm−/− mice is mediated by chromosomal translocations secondary to aberrant responses to dsDNA breaks and that V(D)J recombination is an important, but not essential, event in susceptibility. In contrast to these findings, it was recently reported that Rag1−/− Atm−/− mice do not develop thymic lymphomas, a finding that was interpreted as demonstrating a requirement for RAG-dependent recombination in the susceptibility to tumors in Atm-deficient mice. To test the possibility that RAG-1 and RAG-2 differ in their roles in tumorigenesis, we studied Rag1−/− Atm−/− mice in parallel to our previous Rag2−/− Atm−/− study. We found that thymic lymphomas occur at high frequency in Rag1−/− Atm−/− mice and resemble those that occur in Rag2−/− Atm−/− mice. These results indicate that both RAG-1 and RAG-2 are necessary for tumorigenesis involving translocation in the Tcrα/δ locus but that Atm deficiency leads to tumors through a broader RAG-independent predisposition to translocation, related to a generalized defect in dsDNA break repair.

scholarly journals Assessment of genetic and epigenetic changes during cell culture ageing and relations with somaclonal variation in Coffea arabica

2015 ◽  
Vol 122 (3) ◽  
pp. 517-531 ◽  
Author(s):  
Roberto Bobadilla Landey ◽  
Alberto Cenci ◽  
Romain Guyot ◽  
Benoît Bertrand ◽  
Frédéric Georget ◽  
...  
Keyword(s):  
Cell Culture ◽  
Somaclonal Variation ◽  
Coffea Arabica ◽  
Epigenetic Changes

Effect of mastoid drilling on hearing of the contralateral ear

2013 ◽  
Vol 127 (10) ◽  
pp. 952-956 ◽  
Author(s):  
A Goyal ◽  
P P Singh ◽  
A Vashishth
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Otoacoustic Emissions ◽  
Pure Tone Audiometry ◽  
Otoacoustic Emission ◽  
Prospective Clinical Study ◽  
Distortion Product Otoacoustic Emission ◽  
High Frequencies ◽  
Distortion Product ◽  
Contralateral Ear

AbstractObjectives:This study aimed to: understand the effect that high intensity noise associated with drilling (during otological surgery) has on hearing in the contralateral ear; determine the nature of hearing loss, if any, by establishing whether it is temporary or persistent; and examine the association between hearing loss and various drill parameters.Methods:A prospective clinical study was carried out at a tertiary centre. Thirty patients with unilateral cholesteatoma and normal contralateral hearing were included. Patients were evaluated pre-operatively and for five days following surgery using high frequency pure tone audiometry, and low and high frequency transient evoked and distortion product otoacoustic emission testing.Results:The findings revealed statistically significant changes in distortion product otoacoustic emissions at high frequencies (p = 0.016), and in transient evoked otoacoustic emissions at both low and high frequencies (p = 0.035 and 0.021, respectively). There was a higher statistical association between otoacoustic emission changes and cutting burrs compared with diamond burrs.Conclusion:Drilling during mastoid surgery poses a threat to hearing in the contralateral ear due to noise and vibration conducted transcranially.

scholarly journals Features of chromosomal abnormalities in spontaneous abortion cell culture failures detected by interphase FISH analysis

2004 ◽  
Vol 12 (7) ◽  
pp. 513-520 ◽  
Author(s):  
Igor N Lebedev ◽  
Nadezhda V Ostroverkhova ◽  
Tatyana V Nikitina ◽  
Natalia N Sukhanova ◽  
Sergey A Nazarenko
Keyword(s):  
Cell Culture ◽  
Spontaneous Abortion ◽  
Chromosomal Abnormalities ◽  
Fish Analysis ◽  
Interphase Fish

Direct comparison of levels of genetic variation in tomato detected by a GACA-containing microsatellite probe and by random amplified polymorphic DNA

Genome ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 375-381 ◽  
Author(s):  
W. Rus-Kortekaas ◽  
M. J. M. Smulders ◽  
P. Arens ◽  
B. Vosman
Keyword(s):  
Tissue Culture ◽  
Genetic Variation ◽  
Somaclonal Variation ◽  
Random Amplified Polymorphic Dna ◽  
Dna Fingerprint ◽  
Pairwise Comparisons ◽  
Lycopersicon Pennellii ◽  
Lycopersicon Species ◽  
Polymorphic Bands ◽  
Simple Sequence

In this study, a direct comparison was made of the ability of four selected random amplified polymorphic DNA (RAPD) primers and a GACA-containing microsatellite probe to detect genetic variation in Lycopersicon. Of the 89 RAPD primers initially tested, 85 showed differences between a representative of Lycopersicon pennellii and L. esculentum, but only 4 distinguished among three L. esculentum cultivars. These four primers were subsequently tested on representatives of six Lycopersicon species. In pairwise comparisons of species, all or 14 of the 15 combinations could be distinguished by single primers. When the primers were tested on 15 L. esculentum cultivars, 90 of the 105 combinations could be distinguished by the four primers together. Finally, none of 118 tested primers showed reproducible differences among calli or progeny of régénérants from tissue culture, although some of the plants had inherited morphological mutations. The probe pWVA16, which detects GACA-containing microsatellites, could distinguish in TaqI-digested DNA the representatives of Lycopersicon species as well as all the L. esculentum cultivars tested. The probe was unable to detect polymorphisms among calli and the progeny of regenerants from tissue culture. An analysis of the results showed that the four selected RAPD primers were able to detect polymorphic bands among species at a frequency of 80%, and among cultivars at a frequency of 44%. In contrast, the microsatellite probe detected polymorphic bands at a frequency of 100 and 95%, respectively. The GACA-containing probe did not detect any common bands among the representatives of the six species, while band sharing with RAPDs was 48%. These results indicate that the two methods detect two types of DNA that differ in their degree of variability.Key words: DNA fingerprint, RAPD, simple sequence, somaclonal variation, tissue culture.

scholarly journals Tissue culture-induced somaclonal variation of decreased pollen viability in torenia (Torenia fournieri Lind.)

2013 ◽  
Vol 54 (1) ◽  
pp. 36 ◽  
Author(s):  
ShuLan Sun ◽  
JianQiang Zhong ◽  
ShuHua Li ◽  
XiaoJing Wang
Keyword(s):  
Tissue Culture ◽  
Somaclonal Variation ◽  
Pollen Viability ◽  
Torenia Fournieri

scholarly journals The Estimation of Hydrometeor Profiles from Wideband Microwave Observations

2000 ◽  
Vol 39 (10) ◽  
pp. 1645-1656 ◽  
Author(s):  
Gail M. Skofronick-Jackson ◽  
James R. Wang
Keyword(s):  
High Frequency ◽  
Cloud Water ◽  
Tropical Ocean ◽  
Low Frequencies ◽  
High Frequencies ◽  
Atmospheric Research ◽  
Brightness Temperatures ◽  
Microphysical Properties ◽  
Ice Microphysics ◽  
Updraft Region

Abstract Profiles of the microphysical properties of clouds and rain cells are essential in many areas of atmospheric research and operational meteorology. To enhance the understanding of the nonlinear and underconstrained relationships between cloud and hydrometeor microphysical profiles and passive microwave brightness temperatures, estimations of cloud profiles for an anvil region, a convective region, and an updraft region of an oceanic squall were performed. The estimations relied on comparisons between radiative transfer calculations of incrementally estimated microphysical profiles and concurrent dual-altitude wideband brightness temperatures from the 22 February 1993 flight during the Tropical Ocean and Global Atmosphere Coupled Ocean–Atmosphere Response Experiment. The wideband observations (10–220 GHz) are necessary for estimating cloud profiles reaching up to 20 km. The low frequencies enhance the rain and cloud water profiles, and the high frequencies are required to detail the higher-altitude ice microphysics. A microphysical profile was estimated for each of the three regions of the storm. Each of the three estimated profiles produced calculated brightness temperatures within ∼10 K of the observations. A majority of the total iterative adjustments were to the estimated profile’s frozen hydrometeor characteristics and were necessary to match the high-frequency calculations with the observations. This requirement indicates a need to validate cloud-resolving models using high frequencies. Some difficulties matching the 37-GHz observation channels on the DC-8 and ER-2 aircraft with the calculations simulated at the two aircraft heights (∼11 km and 20 km, respectively) were noted, and potential causes were presented.

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