Surface instability of laminated bodies of regular structure under combination loading

1991 ◽  
Vol 27 (5) ◽  
pp. 443-449 ◽  
Author(s):  
V. P. Korzh ◽  
V. N. Chekhov
Keyword(s):  
Regular Structure ◽  
Surface Instability ◽  
Combination Loading

Interrelationship of the cellular distribution and secretion of regular structure (RS) protein in Bacillus licheniformis nm 105

1992 ◽  
Vol 50 (1) ◽  
pp. 712-713
Author(s):  
Xiaorong Zhu ◽  
Richard McVeigh ◽  
Bijan K. Ghosh
Keyword(s):  
Alkaline Phosphatase ◽  
Bacillus Licheniformis ◽  
Self Assembly ◽  
Gel Electrophoresis ◽  
Culture Supernatant ◽  
Regular Structure ◽  
The Self ◽  
Cellular Distribution ◽  
Structural Protein ◽  
Laboratory Cultures

A mutant of Bacillus licheniformis 749/C, NM 105 exhibits some notable properties, e.g., arrest of alkaline phosphatase secretion and overexpression and hypersecretion of RS protein. Although RS is known to be widely distributed in many microbes, it is rarely found, with a few exceptions, in laboratory cultures of microorganisms. RS protein is a structural protein and has the unusual properties to form aggregate. This characteristic may have been responsible for the self assembly of RS into regular tetragonal structures. Another uncommon characteristic of RS is that enhanced synthesis and secretion which occurs when the cells cease to grow. Assembled RS protein with a tetragonal structure is not seen inside cells at any stage of cell growth including cells in the stationary phase of growth. Gel electrophoresis of the culture supernatant shows a very large amount of RS protein in the stationary culture of the B. licheniformis. It seems, Therefore, that the RS protein is cotranslationally secreted and self assembled on the envelope surface.

REGULAR STRUCTURE OF LOW-LYING STATES FOR ATOMIC NUCLEI UNDER RANDOM INTERACTIONS

2008 ◽  
Vol 17 (supp01) ◽  
pp. 304-317
Author(s):  
Y. M. ZHAO
Keyword(s):  
Ground State ◽  
Collective Motion ◽  
Regular Structure ◽  
Positive Parity ◽  
Many Body ◽  
Random Interactions ◽  
Atomic Nuclei ◽  
Many Body Systems

In this paper we review regularities of low-lying states for many-body systems, in particular, atomic nuclei, under random interactions. We shall discuss the famous problem of spin zero ground state dominance, positive parity dominance, collective motion, odd-even staggering, average energies, etc., in the presence of random interactions.

Effects of Interfacial Tension in Tunneling Microscopy. 2. Experimental Observation of Surface Instability

1996 ◽  
Vol 100 (46) ◽  
pp. 18229-18233 ◽  
Author(s):  
John F. T. Conroy ◽  
Vlado Hlady ◽  
Cynthia J. Bruckner-Lea ◽  
Jiří Janata
Keyword(s):  
Interfacial Tension ◽  
Experimental Observation ◽  
Surface Instability ◽  
Tunneling Microscopy

The maturation of cell wall structure during germination of Bacillus polymyxa spores

1970 ◽  
Vol 16 (9) ◽  
pp. 883-887 ◽  
Author(s):  
R. G. E. Murray ◽  
Myrtle M. Hall ◽  
J. Marak
Keyword(s):  
Cell Wall ◽  
Intermediate Layer ◽  
Single Layer ◽  
Regular Structure ◽  
Wall Structure ◽  
Bacillus Polymyxa ◽  
Rectangular Array ◽  
Crack Open ◽  
Freeze Etching ◽  
Primordial Cell

Sections of germinating spores of Bacillus polymyxa show that the primordial cell wall consists of a single layer. The intermediate layer and an outer rectangular array of macromolecules found on vegetative cells do not appear until the spore coats crack open about 60 min after initiation of germination. The initial areas of the new components appear in patches under the cracks in the coats. Within 10 min the wall is completed and takes on the profile seen in the vegetative cell. Negative staining and freeze-etching techniques show the regular structure to be identical with that previously shown for mature cells, although the subunits are more readily visible in negatively stained preparations.

Stratigraphy and palaeoenvironmental interpretation of late Quaternary colluvial slope deposits in southern Africa

2021 ◽  
Author(s):  
J. Knight
Keyword(s):  
Southern Africa ◽  
Land Surface ◽  
Late Quaternary ◽  
Ecological Factors ◽  
Surface Instability ◽  
Sediment Supply ◽  
Spatial And Temporal Patterns ◽  
Catchment Scale ◽  
Accommodation Space ◽  
Slope Sediment

Abstract Slope and lowland sediment systems throughout southern Africa are dominated by the presence of colluvium with interbedded palaeosols and hardground duricrusts. These sediments correspond to phases of land surface instability and stability, respectively, during the late Quaternary. This study examines the stratigraphy and environmental interpretation of slope sediment records from specific sites in southern Africa for the period of marine isotope stages (MIS) 6 to 1 (~191 ka to present), informed by theoretical ideas of the dynamics of slope systems including sediment supply and accommodation space. Based on this analysis, phases of land surface instability and stability for the period MIS 6 to 1 are identified. The spatial and temporal patterns of land surface conditions are not a simple reflection of climate forcing, but rather reflect the workings of slope systems in response to climate in addition to the role of geologic, edaphic and ecological factors that operate within catchment-scale sediment systems. Considering these systems dynamics can yield a better understanding of the usefulness and limitations of slope sediment stratigraphies.

Cytoskeletal proteins of insect muscle: location of zeelins in Lethocerus flight and leg muscle

1994 ◽  
Vol 107 (5) ◽  
pp. 1115-1129 ◽  
Author(s):  
C. Ferguson ◽  
A. Lakey ◽  
A. Hutchings ◽  
G.W. Butcher ◽  
K.R. Leonard ◽  
...  
Keyword(s):  
Insect Flight ◽  
Regular Structure ◽  
Thick Filament ◽  
Cytoskeletal Proteins ◽  
Stretch Activation ◽  
Insect Muscle ◽  
Thick Filaments ◽  
Flight Muscles ◽  
Leg Muscle ◽  
Low Ionic Strength

Asynchronous insect flight muscles produce oscillatory contractions and can contract at high frequency because they are activated by stretch as well as by Ca2+. Stretch activation depends on the high stiffness of the fibres and the regular structure of the filament lattice. Cytoskeletal proteins may be important in stabilising the lattice. Two proteins, zeelin 1 (35 kDa) and zeelin 2 (23 kDa), have been isolated from the cytoskeletal fraction of Lethocerus flight muscle. Both zeelins have multiple isoforms of the same molecular mass and different charge. Zeelin 1 forms micelles and zeelin 2 forms filaments when renatured in low ionic strength solutions. Filaments of zeelin 2 are ribbons 10 nm wide and 3 nm thick. The position of zeelins in fibres from Lethocerus flight and leg muscle was determined by immunofluorescence and immunoelectron microscopy. Zeelin 1 is found in flight and leg fibres and zeelin 2 only in flight fibres. In flight myofibrils, both zeelins are in discrete regions of the A-band in each half sarcomere. Zeelin 1 is across the whole A-band in leg myofibrils. Zeelins are not in the Z-disc, as was thought previously, but migrate to the Z-disc in glycerinated fibres. Zeelins are associated with thick filaments and analysis of oblique sections showed that zeelin 1 is closer to the filament shaft than zeelin 2. The antibody labelling pattern is consistent with zeelin molecules associated with myosin near the end of the rod region. Alternatively, the position of zeelins may be determined by other A-band proteins. There are about 2.0 to 2.5 moles of myosin per mole of each zeelin. The function of these cytoskeletal proteins may be to maintain the ordered structure of the thick filament.

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