Orientation of diplochromosomes in mitoses of potato (Solatium tuberosum L.) callus cultures

Genome ◽  
1990 ◽  
Vol 33 (3) ◽  
pp. 328-332 ◽  
Author(s):  
L. P. Pijnacker ◽  
M. A. Ferwerda
Keyword(s):  
Callus Cultures ◽  
Opposite Pole ◽  
Solatium Tuberosum ◽  
Sister Chromosome ◽  
Leaf Segments ◽  
Alternate Configuration

The mitotic behaviour of diplochromosomes was investigated in early calli from leaf segments of a monohaploid potato (x = 12) with the aid of the fluorescent plus Giemsa technique. The sister chromosomes of the diplochromosomes do not separate during metaphase because the inner chromatids remain connected. Consequently the diplochromosomes orient in three stable configurations during metaphase. In the case in which sister chromosomes become auto-oriented, the outer chromatids face one pole and the inner chromatids the opposite pole (U-shaped configuration), or the outer and inner chromatid of each sister chromosome face different poles (alternate configuration). Less frequently the sister chromosomes become oriented to different poles (C-shaped configuration). Linear orientation is not observed. At least until the onset of telophase only the inner chromatids originating from U-shaped configurations may remain paired, but they fall apart before the next metaphase. The mitoses with diplochromosomes give rise to two cells with double the number of chromosomes.Key words: potato, diplochromosomes, mitosis, orientation, polyploidization.

SEM and fluorescence imaging of callose deposition in root hair tips and suspension cultures of Streptanthus tortuosus

1990 ◽  
Vol 48 (3) ◽  
pp. 698-699
Author(s):  
K.S. Walters ◽  
R.D. Sjolund ◽  
K.C. Moore
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Cultured Cells ◽  
Root Hairs ◽  
Callus Cultures ◽  
Callose Deposition ◽  
Culture Cells ◽  
Wall Structures ◽  
Ultraviolet Illumination ◽  
Callose Formation

Callose, B-1,3-glucan, a component of cell walls, is associated with phloem sieve plates, plasmodesmata, and other cell wall structures that are formed in response to wounding or infection. Callose reacts with aniline blue to form a fluorescent complex that can be recognized in the light microscope with ultraviolet illumination. We have identified callose in cell wall protuberances that are formed spontaneously in suspension-cultured cells of S. tortuosus and in the tips of root hairs formed in sterile callus cultures of S. tortuosus. Callose deposits in root hairs are restricted to root hair tips which appear to be damaged or deformed, while normal root hair tips lack callose deposits. The callose deposits found in suspension culture cells are restricted to regions where unusual outgrowths or protuberances are formed on the cell surfaces, specifically regions that are the sites of new cell wall formation.Callose formation has been shown to be regulated by intracellular calcium levels.

Structuralism’s casus. Article second

2020 ◽  
Vol 25 (4) ◽  
pp. 82-93
Author(s):  
Vladimir A. Martynov
Keyword(s):  
Philosophy Of Science ◽  
Institutional Approach ◽  
Opposite Pole ◽  
Constructivist Model

This article concludes the series of publications on structuralism. In the three previous articles, the hypothesis that structuralism cannot be understood and appreciated outside of what can be called “modern humanism” was first expressed and substantiated. In this article, structuralism, understood in its ontogeny and phylogeny, is related to the horizon of modern epistemology and philosophy of science. Moreover, modern epistemological models must themselves be taken seriously, i. e. methods of modern comparative epistemology. Thus, the map of theories of structuralism is more complicated to see than with a strictly institutional approach. One of the poles of this whole is radically constructivist models (the most complete constructivist model of structuralism today is the concept of N. Poselyagin). The opposite pole is the realistic understanding of structuralism proposed in this series of publications. A number of models reveal fundamental complexity, revealing a realistic background under the layer of constructivist rhetoric. Thus, the theory of structuralism of the greatest epistemologist and methodologist of science P. Serio turns out to be dual. Corrections to the archeology of M. Foucault’s knowledge inevitably lead his theory to the realistic pole.

Leaf Color of Plants Regenerated through In Vitro Culture from Variegated Leaf Segments of Caladium.

1993 ◽  
Vol 62 (3) ◽  
pp. 619-624 ◽  
Author(s):  
Yu Zhu ◽  
Tetsuyuki Takemoto ◽  
Susumu Yazawa
Keyword(s):  
In Vitro Culture ◽  
Leaf Color ◽  
Leaf Segments ◽  
Variegated Leaf

In Vitro Establishment of Powdery Mildew (Microsphaera pulchra) on Microshoots of Flowering Dogwood

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 506a-506
Author(s):  
L.A. Klein ◽  
M.T. Windham ◽  
R.N. Trigiano
Keyword(s):  
Powdery Mildew ◽  
Woody Plant ◽  
Infected Individual ◽  
Callus Cultures ◽  
Fungal Culture ◽  
Culture Collections ◽  
Flowering Dogwood ◽  
Plant Parasite ◽  
In Vitro Establishment

Microshoot and callus cultures of Cornus florida (flowering dogwood), which were grown on woody plant medium amended with BA, were inoculated with Microsphaera pulchra (an obligate plant parasite) by gently shaking infected leaves bearing numerous conidia over the tissue. Culture dishes were sealed with parafilm and incubated at 24 °C with 25 mol·m–2·s–1 provided by cool fluorescent bulbs for 15 h. Cultures were examined with a dissecting scope every 24 h and cultures transferred when contaminating fungi were present. Specimens were prepared light microscopy and SEM. The fungus infected individual callus cells, but did not sporulate. In contrast, powdery mildew was well-established (both primary and secondary hyphae) in 70% of the microshoot cultures after 6 days and sporulated on 20% by 7 to 8 days. The cellular relationship between host and pathogen in vitro was similar to that found in greenhouse-grown plants. This technique has possible applications in maintaining fungal culture collections and studying host–pathogen relationships under more stringently controlled conditions.

Comparative Investigation on Formation and Accumulation of Rare Phenylpropanoids in Plants and in vitro Cultures of Pimpinella major

1990 ◽  
Vol 45 (6) ◽  
pp. 602-606 ◽  
Author(s):  
B. Merkel ◽  
J. Reichling
Keyword(s):  
Callus Culture ◽  
Nutrient Medium ◽  
Callus Cultures ◽  
Comparative Investigation ◽  
In Vitro Cultures ◽  
Liquid Nutrient Medium ◽  
Whole Plants ◽  
Plant Seedlings

Abstract Unorganized callus and leaf/root-differentiating callus cultures of Pimpinella major have been established in liquid nutrient medium. Their capacity to accumulate rare phenylpropanoids such as epoxy-pseudoisoeugenol tiglate, epoxy-anol tiglate and anol tiglate was compared with that of seedlings and whole plants. The unorganized callus cultures were not able to accumulate any phenylpropanoids. In comparison, the leaf/root-differentiating callus culture promoted the accumulation of epoxy-pseudoisoeugenol tiglate (up to 90 mg/100 g fr.wt.) but not that of anol-derivatives. The accumulated amount of EPT in PMD-SH was comparable with that in plant seedlings.

Elicitor-mediated enhancement of biomass, polyphenols, mangiferin production and antioxidant activities in callus cultures of Salacia chinensis L.

3 Biotech ◽  
2021 ◽  
Vol 11 (6) ◽  
Author(s):  
Jaykumar J. Chavan ◽  
Parthraj R. Kshirsagar ◽  
Sharad G. Jadhav ◽  
Virdhaval M. Nalavade ◽  
Swati T. Gurme ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Callus Cultures

scholarly journals Pathways for Homologous Recombination Between Chromosomal Direct Repeats in Salmonella typhimurium

Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 751-767 ◽  
Author(s):  
Timothy Galitski ◽  
John R Roth
Keyword(s):  
Homologous Recombination ◽  
Strand Break ◽  
Dna Lesions ◽  
General View ◽  
Direct Repeats ◽  
Sexual Recombination ◽  
Sister Chromosome ◽  
Lactose Utilization ◽  
Recf Pathway ◽  
Chromosome Exchanges

Homologous recombination pathways probably evolved primarily to accomplish chromosomal repair and the formation and resolution of duplications by sister-chromosome exchanges. Various DNA lesions initiate these events. Classical recombination assays, involving bacterial sex, focus attention on double-strand ends of DNA. Sexual exchanges, initiated at these ends, depend on the RecBCD pathway. In the absence of RecBCD function, mutation of the sbcB and sbcC genes activates the apparently cryptic RecF pathway. To provide a more general view of recombination, we describe an assay in which endogenous DNA damage initiates recombination between chromosomal direct repeats. The repeats flank markers conferring lactose utilization (Lac+) and ampicillin resistance (ApR); recombination generates Lac-ApS segregants. In this assay, the RecF pathway is not cryptic; it plays a major role without sbcBC mutations. Others have proposed that single-strand gaps are the natural substrate for RecF-dependent recombination. Supporting this view, recombination stimulated by a double-strand break (DSB) in a chromosomal repeat depended on RecB function, not RecF function. Without RecBCD function, sbcBC mutations modified the RecF pathway and allowed it to catalyze DSB-stimulated recombination. Sexual recombination assays overestimate the importance of RecBCD and DSBs, and underestimate the importance of the RecF pathway.

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