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Axial and radial pressure exerted by earthworms of different ecological groups (1999)

Keudel, M. ; Schrader, S.

Springer

Biology and fertility of soils 29 (1999), S. 262-269

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ISSN: 1432-0789

Keywords: Keywords Axial pressure ; Earthworms ; Ecological groups ; Radial pressure ; Burrowing activity

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The aim of this study was to measure the pressures exerted by earthworms during burrowing. For this purpose we developed two methods with which to quantify the axial and radial pressure. The data were recorded with an electronic balance that was connected to a PC. Artificial earthworm burrows were used to standardize the measurements. Plexiglas tubes with diameters ranging from 2 to 6.3 mm which corresponded to the diameter of the earthworms were used. A pin was placed inside the tubes, on which the earthworms exerted a pressure by peristaltic locomotion. Only the maximum values of the pressure measurement were taken into account for evaluation, and the arithmetic mean was calculated. The measurements were conducted with Aporrectodea longa, Lumbricus terrestris, Aporrectodea caliginosa, Octolasion cyaneum, Allolobophora chlorotica, Aporrectodea rosea, Lumbricus rubellus and Dendrobaena octaedra. The species examined were classified into ecological groups. The mean axial pressures exerted by each group were in the order: epigeic (14–25 kPa), endogeic (27–39 kPa) and anecic (46–65 kPa). For the mean radial pressure the order was: epigeic (39–63 kPa), anecic (72–93 kPa) and endogeic (59–195 kPa). It was apparent from the results that radial pressure is the most important pressure with respect to the burrowing activity of earthworms.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s003740050551

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Autostimulatory mechanisms in myeloid leukemogenesis (1987)

Schrader, J. W. ; Leslie, K. B. ; Ziltener, H. J. ; [et al.]

New York, N.Y. : Wiley-Blackwell

Journal of Cellular Biochemistry 34 (1987), S. 39-46

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ISSN: 0730-2312

Keywords: c-myb rearrangement ; granulocyte-macrophage colony-stimulating factor ; panspecific hemopoietin ; interlcukin-3 ; autostimulation ; myeloid leukemia ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: WEHI-274 is a monocytic leukemia that arose in a BALB/c mouse infected with Abelson murine leukemia virus. A series of subclones were derived from early passages of this tumor. Three subsets of these leukemogenic subclones were identified. Two subsets demonstrated autostimulatory patterns of growth. This was due to the ectopic production of the T-cell lymphokine the panspecific hemopoietin IL-3 in one case and of the T-cell lymphokine granulocyte-macro-phage colony-stimulating factor (GM-CSF) in the other. The third type of subclone did not secrete any autostimulatory growth factor. In the subclone producing IL-3, one copy of IL-3 gene was rearranged and abnormal IL-3 RNA transcripts were present in the nucleus. Subclones producing GM-CSF also contained abnormal GM-CSF RNA transcripts, although no rearrangement of the GM-CSF gene was detected. All three sets of subclones shared a common rearrangement of one c-myb oncogene, suggesting that they share a common ancestor. These results suggest that initiation or progression of leukemogenic behavior in this abnormal clone occurred in three different ways, two of which involved autostimulation by the ectopic activation of T-cell lymphokine genes.

Additional Material: 1 Ill.