scholarly journals DNA level in guard cells nuclei of Ornithogalum umbellatum ovary is 2C-4C

2011 ◽  
Vol 77 (3) ◽  
pp. 207-211
Author(s):  
Maria Kwiatkowska ◽  
Katarzyna Rogala ◽  
Katarzyna Popłońska
Keyword(s):  
Dna Content ◽  
Guard Cell ◽  
Flower Development ◽  
Maximum Level ◽  
Guard Cells ◽  
The Other ◽  
Feulgen Reaction ◽  
Cell Nuclei ◽  
Other Hand ◽  
Ovary Growth

The DNA content after Feulgen reaction in the guard cells and epidermis of <em>Omithogalum umbellatum</em> ovary was cytophotometrically measured in different phases of flower development. Only in bud of flowers guard cells DNA content was 2C while in full blown flowers it was higher, between 2C-4C. This observation was supported by autoradiographic studies with 3H-thymidine which was incorporated into guard cell nuclei in the ovary epidermis of newly developed flowers. Thus DNA level in <em>O. umbellatum</em> guard cells was higher than those in other plants described in literature. On the other hand, DNA content in the epidermis cells increased gradually with ovary growth reaching the maximum level of 8C in some cells.

scholarly journals Demonstration of chromatinic structures in avian tubercle bacilli in the early stages of development

1947 ◽  
Vol 45 (4) ◽  
pp. 413-416 ◽  
Author(s):  
E. M. Brieger ◽  
C. F. Robinow
Keyword(s):  
Hydrochloric Acid ◽  
Early Development ◽  
The Other ◽  
Feulgen Reaction ◽  
Cytological Investigation ◽  
Stages Of Development ◽  
The Third ◽  
Early Stages ◽  
Other Hand ◽  
The Masses

In a cytological investigation of three branching and two non-branching strains grown on Loewenstein medium, it was found that avian tubercle bacilli contain chromatinic material which gives a positive Feulgen reaction and is readily stainable with Giemsa's solution after treatment of the fixed bacteria with hydrochloric acid.Growing filamentous forms of both ‘bacterial’ and ‘mycelial’ strains from 1 to 2 day old cultures contain variable numbers of irregularly spaced, more or less spherical chromatinic bodies which vary in staining in the same bacillus, some being red, others purple. During the third or fourth day the chromatinic material in the bacteria increases very much until most of it is fused into an almost homogeneous deeply stained column. In thenon-branchingstrains the filamentous forms with high chromatin content soon break up into small mono-or binucleate elements, and the same holds true for the ‘straight’ filamentous forms which are also present in cultures of branching strains. The ‘mycelial’ forms, on the other hand, disintegrate at this time (fourth or fifth day of cultivation), and it is uncertain whether they contribute (by partial fragmentation) to the masses of small mono- or binucleate forms which are the predominant element in old cultures of all the strains investigated.The chromatinic structures of avian tubercle bacilli have the same staining properties as those of ordinary non-acid-fast bacteria but differ from them in their behaviour during the early development of the bacilli.

Organogénie florale des genres Culcasia et Cercestis (Araceae)

1996 ◽  
Vol 74 (6) ◽  
pp. 898-908 ◽  
Author(s):  
Denis Barabé ◽  
Charles Bertrand
Keyword(s):  
Flower Development ◽  
Floral Development ◽  
Intermediate Zone ◽  
The Other ◽  
Other Hand ◽  
Unisexual Flowers ◽  
Male Flowers ◽  
Morphogenetic Gradient ◽  
Female Flowers

The floral development of Culcasia saxatilis, Culcasia tenuifolia, and Cercestis stigmaticus has been analyzed. These two genera possess unisexual flowers without perianth. In these species, the cylindrical inflorescence carry male flowers in the upper part and female flowers in the lower part. In C. tenuifolia, the separation between the female zone and the male zone is very sharp. There is no intermediate zone. In C. saxatilis and C. stigmaticus, we may observe rudimentary bisexual flowers between the two zones. In this intermediate zone, flowers located near the male zone possess male appendages more developped than those located near the female zone. On the other hand, the flowers located near the female zone possess female appendages more developped than those located near the male zone. The results suggest the existence of a morphogenetic gradient in the inflorescence of some species of Araceae. Keywords: morphogenesis, gradient, flower, development, inflorescence.

scholarly journals STUDIES ON THE FEULGEN REACTION WITH HISTOCHEMICAL MODEL SYSTEMS

1964 ◽  
Vol 12 (10) ◽  
pp. 758-767 ◽  
Author(s):  
M. J. HARDONK ◽  
P. VAN DUIJN
Keyword(s):  
Crystal Violet ◽  
Deoxyribonucleic Acid ◽  
Spectral Shift ◽  
The Other ◽  
Model Systems ◽  
Cellulose Film ◽  
Feulgen Reaction ◽  
Cell Nuclei ◽  
Amino Groups ◽  
Schiff Reaction

The absorption spectra of Feulgen-stained deoxyribonucleic acid (DNA)-containing membranes have been studied under various conditions. The absorption curve of the Feulgen-stained DNA-cellulose differs from those of the other model systems and is comparable to that of a solution of apurinic acid stained by the Schiff reaction. The spectral shift caused by the reaction of formaldehyde and SO2 with the stained films was used as a criterion for the degree of substitution of the bound pararosaniline. The spectrum of DNA-cellulose, unlike the spectra of the other models, did not show any change under the action of these reagents. This indicates that the three amino groups of pararosaniline are all bound to the DNA in a stained DNA-cellulose film. When the mobility of the apurinic acid chain is restricted, the formation of the trisubstituted product is apparently hindered. Such a situation may be present in DNA-containing polyacrylamide films containing proteins and also in cell nuclei. From a study of the literature it is concluded that the shoulder in the pararosaniline spectrum is most probably caused by a configurational isomer of the dye as indicated by Lewis et al. (16) for crystal violet. To explain the abnormal spectrum of the stained DNA-cellulose, it is proposed that in this case pararosaniline is bound with the three amino groups to three neighbouring deoxyribose groups in the hydrolyzed DNA. Studies with Stuart models of the molecules involved showed that in this case one conformation isomer of pararosaniline can be constructed more easily than the other. This situation may explain the spectrum of the stained DNA-cellulose. The other spectral results could also be interpreted on basis of this hypothesis.

scholarly journals Genome size of the European domestic goose (Anser anser domesticus)

2009 ◽  
Vol 89 (4) ◽  
pp. 449-455 ◽  
Author(s):  
K Andraszek ◽  
E Wójcik ◽  
A Grużewska ◽  
E Smalec
Keyword(s):  
Genome Size ◽  
Dna Content ◽  
Cell Types ◽  
Heart Cells ◽  
Feulgen Reaction ◽  
Cell Nuclei ◽  
Anser Anser ◽  
Ovary Cells ◽  
Nucleus Surface ◽  
Chicken Erythrocytes

This work is aimed at determining the C-DNA contained within the nuclei of different types of cells in the domestic goose Anser anser. Cells from the lungs, skin, pancreas, kidney, spleen, liver, heart, brain, blood, ovary and testicle were analysed. Cells from the blood, ovary and testicle were smeared onto microscopic glasses, whereas slides from the other organs and tissues were prepared using the paraffin technique. DNA content, as visualized by the Feulgen reaction using computerized image analysis, was examined in 200 nuclei of every type of cell. Chicken erythrocytes were used as reference material. Different concentrations of chromatin within cell nuclei were observed, from small, dispersed clods to an entirely filled nucleus surface. It was stated that the average C-DNA content in the domestic European goose amounts to 1.306 ± 0.327 pg, which gives goose DNA a length in base pair of 1.277 × 109 ± 0.320 × 109 bp after adjustment. The correlation between nucleus size and the C-DNA content was positive and high. In all cell types it exceeded 0.6. The highest was observed in lung and ovary cells, the lowest in skin and the pancreas. The majority of all cells (57.34%) contain DNA at the range between 1.0 to 1.5 pg, especially those from erythrocytes and the pancreas (82 and 76% respectively). Liver cells demonstrate a tendency toward an amount that is higher than 1.5% of the DNA (78.61% cells). Heart cells reveal a tendency downward (98.99% below 1.5 pg). Less than 1.0 pg of DNA was observed in 17.13% of all examined cells. Key words: Domestic goose, cell, cell nuclei, Feulgen reaction, genome size, DNA mass

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Don’t Put Me in This Group

2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke
Keyword(s):  
Positive Emotions ◽  
Negative Emotions ◽  
Negative Information ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Group Memberships

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.

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