Stress-induced changes in accumulation of sorbitol and in activities of concomitant enzymes in digestive gland of freshwater snail

2009 ◽  
Vol 74 (11) ◽  
pp. 1260-1265 ◽  
Author(s):  
I. L. Tsvetkov ◽  
A. S. Konichev
Keyword(s):  
Digestive Gland ◽  
Freshwater Snail ◽  
Induced Changes

Localization and fate of aluminium in the digestive gland of the freshwater snail Lymnaea stagnalis

2000 ◽  
Vol 32 (1) ◽  
pp. 79-87 ◽  
Author(s):  
R. Elangovan ◽  
C.R. McCrohan ◽  
S. Ballance ◽  
J.J. Powell ◽  
K.N. White
Keyword(s):  
Digestive Gland ◽  
Lymnaea Stagnalis ◽  
Freshwater Snail

Effects of seasonal change and prolonged anoxia on metabolic enzymes of Littorina littorea

2001 ◽  
Vol 79 (5) ◽  
pp. 907-915 ◽  
Author(s):  
Steven C Greenway ◽  
Kenneth B Storey
Keyword(s):  
Pyruvate Kinase ◽  
Digestive Gland ◽  
Seasonal Change ◽  
Littorina Littorea ◽  
Kinetic Properties ◽  
Enzyme Kinetic ◽  
Seasonal Differences ◽  
Exposure In Vivo ◽  
Induced Changes

The effects of seasonal change (July versus November) and prolonged anoxia (N2 atmosphere at 5 or 10°C for 6 days) exposure in vivo on the activities of 18 enzymes, as well as the kinetic properties of phosphofructokinase (PFK) and pyruvate kinase (PK), were investigated in foot muscle and digestive gland of the marine periwinkle Littorina littorea L. Seasonal differences in enzyme maximal activities were tissue-specific, with generally increased activities during the summer and changes in a greater number of enzymes in digestive gland than in foot muscle. Seasonal differences in the kinetic properties of PFK and PK were observed in both tissues. PK from digestive gland of winter animals showed a much higher S0.5 for phosphoenolpyruvate and stronger changes in enzyme kinetic properties in response to anoxia than did the enzyme in summer animals; this may suggest the presence of seasonal isozymes. The effects of anoxia were tissue- and season-specific. Anoxia exposure during the winter induced a greater number of changes in enzyme maximal activities in foot muscle than in digestive gland. Anoxia-induced changes in the kinetic properties of both PFK and PK were also seen in both organs. For PK, these changes were consistent with less active enzyme forms in the anoxic state. Hence, both seasonal and environmental (anoxia) factors influence enzyme maximal activities and kinetic properties in L. littorea.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

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