Seasonal adaptation of crucian carp (Carassius carassius L.) heart: glycogen stores and lactate dehydrogenase activity

1994 ◽  
Vol 72 (3) ◽  
pp. 433-442 ◽  
Author(s):  
Matti Vornanen
Keyword(s):  
Lactate Dehydrogenase ◽  
Crucian Carp ◽  
Glycogen Content ◽  
Early Summer ◽  
Winter Period ◽  
Kinetic Properties ◽  
Seasonal Adaptation ◽  
Lactate Dehydrogenase Activity ◽  
Glycogen Stores ◽  
Α Particles

The glycogen content of the crucian carp heart followed a clear annual cycle, while the size of the heart remained constant throughout the year. Glycogen stores were very abundant at the beginning of the winter (8% of heart mass) and were consumed during the winter and spring, so the stores were at their minimum in early summer (1.4% in May). New glycogen depositions accumulated in the heart during summer and autumn, the maximum glycogen content being attained at the end of October. Glycogen occurred in two distinct granular forms: small β particles about 25 nm in diameter and large α particles about 100 nm in diameter. In late autumn glycogen was mainly in the form of small β particles, which were gathered in vast "glycogen seas" up to 45 μm in length and 10 μm in width. In spring and especially in summer the larger α particles were more numerous than β particles. Lactate dehydrogenase (LDH) activity of the crucian carp heart was relatively high and constant throughout the year. The kinetic properties of cardiac LDH were intermediate between pure cardiac and pure muscle type LDH with a low Km value (0.1 mM) for pyruvate, but only moderately (30%) inhibited by high pyruvate concentrations. The isoenzyme composition and kinetics of LDH did not change seasonally. Crucian carp showed an immediate and strong reduction in heart rate when exposed to hypoxic water. These findings suggest that the crucian carp heart tolerates a long hypoxic winter period by suppressing energy consumption with strong bradycardic reflex and utilizing the massive glycogen stores of the tissues through anaerobic metabolism.

Seasonal changes in glycogen content and Na+-K+-ATPase activity in the brain of crucian carp

2006 ◽  
Vol 291 (5) ◽  
pp. R1482-R1489 ◽  
Author(s):  
Matti Vornanen ◽  
Vesa Paajanen
Keyword(s):  
Atpase Activity ◽  
Seasonal Changes ◽  
Crucian Carp ◽  
Glycogen Content ◽  
Hill Coefficient ◽  
Ouabain Binding ◽  
Brain Glycogen ◽  
Na Pump ◽  
Glycogen Stores ◽  
The Brain

Changes in the number of Na+-K+-ATPase α-subunits, Na+-K+-ATPase activity and glycogen content of the crucian carp ( Carassius carassius) brain were examined to elucidate relative roles of energy demand and supply in adaptation to seasonal anoxia. Fish were collected monthly around the year from the wild for immediate laboratory assays. Equilibrium dissociation constant and Hill coefficient of [3H]ouabain binding to brain homogenates were 12.87 ± 2.86 nM and −1.18 ± 0.07 in June and 11.93 ± 2.81 nM and −1.17 ± 0.06 in February ( P > 0.05), respectively, suggesting little changes in Na+-K+-ATPase α-subunit composition of the brain between summer and winter. The number of [3H]ouabain binding sites and Na-K-ATPase activity varied seasonally ( P < 0.001) but did not show clear connection to seasonal changes in oxygen content of the fish habitat. Six weeks’ exposure of fish to anoxia in the laboratory did not affect Na+-K+-ATPase activity ( P > 0.05) confirming the anoxia resistance of the carp brain Na pump. Although anoxia did not suppress the Na pump, direct Q10 effect on Na+-K+-ATPase at low temperatures resulted in 10 times lower catalytic activity in winter than in summer. Brain glycogen content showed clear seasonal cycling with the peak value of 203.7 ± 16.1 μM/g in February and a 15 times lower minimum (12.9 ± 1.2) in July. In winter glycogen stores are 15 times larger and ATP requirements of Na+-K+-ATPase at least 10 times less than in summer. Accordingly, brain glycogen stores are sufficient to fuel brain function for about 8 min in summer and 16 h in winter, meaning about 150-fold extension of brain anoxia tolerance by seasonal changes in energy supply-demand ratio.

scholarly journals Kinetic analysis of duck ε-crystallin, a lens structural protein with lactate dehydrogenase activity

1990 ◽  
Vol 267 (1) ◽  
pp. 51-58 ◽  
Author(s):  
S H Chiou ◽  
H J Lee ◽  
G G Chang
Keyword(s):  
Lactate Dehydrogenase ◽  
Kinetic Analysis ◽  
Substrate Inhibition ◽  
Product Inhibition ◽  
Enzyme Mechanism ◽  
Kinetic Properties ◽  
Structural Protein ◽  
Lactate Dehydrogenase Activity ◽  
Chicken Heart ◽  
Inhibition Studies

Biochemical characterization and kinetic analysis of epsilon-crystallin from the lenses of common ducks were undertaken to elucidate the enzyme mechanism of this unique crystallin with lactate dehydrogenase (LDH) activity. Despite the structural similarities between epsilon-crystallin and chicken heart LDH, differences in charge and kinetic properties were revealed by isoenzyme electrophoresis and kinetic studies. Bi-substrate kinetic analysis examined by initial-velocity and product-inhibition studies suggested a compulsory ordered Bi Bi sequential mechanism with NADH as the leading substrate followed by pyruvate. The products were released in the order L-lactate and NAD+. The catalysed reaction is shown to have a higher rate in the formation of L-lactate and NAD+. Substrate inhibition was observed at high concentrations of pyruvate and L-lactate for the forward and reverse reactions respectively. The substrate inhibition was presumably due to the formation of epsilon-crystallin-NAD(+)-pyruvate or epsilon-crystallin-NADH-L-lactate abortive ternary complexes, as suggested by the product-inhibition studies. The significance and the interrelationship of duck epsilon-crystallin with other well-known LDHs are discussed with special regard to its role as a structural protein with some enzymic function in lens metabolism.

Lactate dehydrogenase activity and its isoenzymes in concentric layers of adult bovine and calf lenses

1987 ◽  
Vol 6 (4) ◽  
pp. 555-560 ◽  
Author(s):  
David Sempol ◽  
Edurado Osinaga ◽  
Seymour Zigman ◽  
Israel Korc ◽  
Beatriz Korc ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Lactate Dehydrogenase Activity

scholarly journals l-mandelate dehydrogenase from Rhodotorula graminis: comparisons with the l-lactate dehydrogenase (flavocytochrome b2) from Saccharomyces cerevisiae

1993 ◽  
Vol 290 (1) ◽  
pp. 103-107 ◽  
Author(s):  
O Smékal ◽  
M Yasin ◽  
C A Fewson ◽  
G A Reid ◽  
S K Chapman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lactate Dehydrogenase ◽  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Dimensional Structure ◽  
Striking Difference ◽  
Kinetic Properties ◽  
Proton Abstraction ◽  
Rate Determining Step ◽  
Kinetic Isotope

L-Lactate dehydrogenase (L-LDH) from Saccharomyces cerevisiae and L-mandelate dehydrogenase (L-MDH) from Rhodotorula graminis are both flavocytochromes b2. The kinetic properties of these enzymes have been compared using steady-state kinetic methods. The most striking difference between the two enzymes is found by comparing their substrate specificities. L-LDH and L-MDH have mutually exclusive primary substrates, i.e. the substrate for one enzyme is a potent competitive inhibitor for the other. Molecular-modelling studies on the known three-dimensional structure of S. cerevisiae L-LDH suggest that this enzyme is unable to catalyse the oxidation of L-mandelate because productive binding is impeded by steric interference, particularly between the side chain of Leu-230 and the phenyl ring of mandelate. Another major difference between L-LDH and L-MDH lies in the rate-determining step. For S. cerevisiae L-LDH, the major rate-determining step is proton abstraction at C-2 of lactate, as previously shown by the 2H kinetic-isotope effect. However, in R. graminis L-MDH the kinetic-isotope effect seen with DL-[2-2H]mandelate is only 1.1 +/- 0.1, clearly showing that proton abstraction at C-2 of mandelate is not rate-limiting. The fact that the rate-determining step is different indicates that the transition states in each of these enzymes must also be different.

Natural mortality from poor condition in Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (4) ◽  
pp. 826-836 ◽  
Author(s):  
Jean-Denis Dutil ◽  
Yvan Lambert
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Negative Impact ◽  
Fish Muscle ◽  
Early Summer ◽  
Wild Fish ◽  
Natural Mortality ◽  
Muscle Lactate ◽  
Lactate Dehydrogenase Activity ◽  
Poor Condition

The extent of energy depletion was assessed in Atlantic cod (Gadus morhua) in spring and early summer (1993-1995) to assess relationships between poor condition and natural mortality. Several indices of condition were compared in wild fish in the northern Gulf of St. Lawrence and in fish exposed to a prolonged period of starvation in laboratory experiments. Discriminant analyses classified only a small fraction of the wild fish as similar to cod that did not survive and a much larger fraction as similar to cod that survived starvation. This percentage increased from April to May and peaked in June 1993 and 1994. Condition factor and muscle somatic index allowed a clear distinction between live and dead fish. Muscle lactate dehydrogenase activity suggested that cod had experienced a period of negative growth early in 1993, 1994, and 1995. Fish classified as similar to starved individuals were characterized by a higher gonad to liver mass ratio than others. Reproduction may have a negative impact on survival not only in spring but also later into summer, as some individuals were found not to have recovered by late summer. This study shows that natural mortality from poor condition contributed to lower production in the early 1990s.

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