The relationship of morphogenetic potency of tobacco tissue culture and its cytogenetic features

1974 ◽  
Vol 16 (4) ◽  
pp. 262-274 ◽  
Author(s):  
Nediyalka A. Zagorska ◽  
Zlata B. Shamina ◽  
Raisa G. Butenko
Keyword(s):  
Tissue Culture ◽  
Tobacco Tissue Culture ◽  
Relationship Of ◽  
The Relationship

scholarly journals MICROBIAL PERSISTENCE

1966 ◽  
Vol 123 (3) ◽  
pp. 445-468 ◽  
Author(s):  
Robert M. McCune ◽  
Floyd M. Feldmann ◽  
Harold P. Lambert ◽  
Walsh McDermott
Keyword(s):  
Tissue Culture ◽  
Experimental Procedure ◽  
The Third ◽  
Large Populations ◽  
Tissue Homogenates ◽  
The One ◽  
Time Required ◽  
Relationship Of ◽  
The Relationship

A previously reported form of microbial persistence whereby large populations of tubercle bacilli can be made to "vanish" uniformly from the tissues of mice has been shown to occur generally throughout each group of animals subjected to the experimental procedure; it does not reflect the eradication of the bacilli in the majority of animals with their persistence and ultimate revival in only a minority. The one demonstrable alteration of the tubercle bacilli while "vanished" is that they are sterile. Thus, they are undetectable by cell-free culture, tissue culture, and blind animal passage, i.e. by any method based on microbial multiplication. Whether they have also undergone alteration in morphology and persist in some unconventional form cannot be stated. Acid-fast forms similar to tubercle bacilli can be detected in small numbers by intensified microscopic search of tissue homogenates but the relationship of these forms to the sterile bacilli that ultimately revive is unclear. Thus, the persisting tubercle bacilli are more correctly designated as being in a "sterile state" than one of true latency. The uniform induction of the sterile state is a specific phenomenon requiring the participation of both the nicotinamide derivative, pyrazinamide, and isoniazid. Once assumed, this sterile state is relatively stable and the time required for revival of the tubercle bacilli in the spleens in one-half the animals is seven months. This process can be speeded up by the administration of large doses of cortisone in the third or fourth month after sterilization but revival is not significantly affected by the administration of cortisone earlier.

Anti-hypertensive Lipid from Tissue Culture of Renomedullary Interstitial Cells of the Rat

1976 ◽  
Vol 51 (s3) ◽  
pp. 287s-290s
Author(s):  
E. E. Muirhead ◽  
W. A. Rightsel ◽  
B. E. Leach ◽  
L. W. Byers ◽  
J. A. Pitcock ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Tissue Culture ◽  
Interstitial Cell ◽  
Cultured Cells ◽  
Interstitial Cells ◽  
Renin Angiotensin ◽  
Cell Hormone ◽  
Relationship Of ◽  
The Relationship

1. Allogenic transplants of cultured renomedullary interstitial cells exert a powerful anti-hypertensive action. The blood pressure of hypertensive animals usually drops slowly over 8–12 h whereas the pulse is unchanged or reduced. 2. Lipids derived from the cultured cells exert a similar anti-hypertensive action. 3. The anti-hypertensive action of transplanted cultured cells almost certainly results from the secretion of a substance(s) that acts in the manner of a hormone. The tissue culture lipid is a prime candidate hormone. 4. The relationship of the kidney to the hypertensive state is considered to entail pro- and antihypertensive actions. The pro-hypertensive actions include (a) activation of the renal pressor system (mainly renin—angiotensin), (b) failure to prevent sodium and fluid overloading because of either an injured or absent kidney or the excessive action of mineralocorticoids (mainly aldosterone). The antihypertensive actions of the kidney include (a) the relief of sodium and fluid overloading through diuresis—natriuresis and (b) the action of the renomedullary interstitial cell hormone (the antihypertensive renomedullary hormone).

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

The relationship of IGE receptor topography to signaling activity in RBL-2H3 mast cells

1991 ◽  
Vol 49 ◽  
pp. 236-237
Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver
Keyword(s):  
Mast Cells ◽  
Protein A ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Ige Binding ◽  
Electron Imaging ◽  
Small Clusters ◽  
Relationship Of ◽  
The Relationship

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.

Sign in / Sign up

Export Citation Format

Share Document