Effects of declining calcium availability on the survival, growth and calcium content of a freshwater crayfish,Orconectes virilis

2016 ◽  
Vol 61 (6) ◽  
pp. 914-922 ◽  
Author(s):  
Brie A. Edwards ◽  
Donald A. Jackson ◽  
Keith M. Somers
Keyword(s):  
Calcium Content ◽  
Freshwater Crayfish ◽  
Orconectes Virilis ◽  
Calcium Availability

Effects of E. coli sepsis and myocardial depressant factor on interval-force relations in dog ventricle

1993 ◽  
Vol 264 (5) ◽  
pp. H1402-H1410 ◽  
Author(s):  
P. Jha ◽  
H. Jacobs ◽  
D. Bose ◽  
R. Wang ◽  
J. Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Steady State ◽  
Sarcoplasmic Reticulum ◽  
Calcium Metabolism ◽  
Calcium Content ◽  
Left Ventricular ◽  
Muscle Preparation ◽  
E Coli ◽  
Calcium Availability ◽  
Fractional Release

We examined whether depressed left ventricular (LV) contractility during Escherichia coli sepsis in dogs was due to a decrease in the fractional release of calcium from the sarcoplasmic reticulum (SR) or a reduction in calcium content in this organelle. To indirectly assess SR calcium availability in a right ventricular (RV) trabecular muscle preparation, we utilized functional indexes of cellular myocardial calcium metabolism, which included rapid-cooling contracture (RCC), an indicator of SR calcium content, and postrest contraction (PRC), an index of calcium availability from the release compartment of the SR. Measurements were made during steady-state stimulation at 0.5 and 1.5 Hz, during which time rest intervals of 30-240 s were periodically imposed. SR calcium availability was measured in RV trabeculae of dogs subjected to 4 h of E. coli sepsis and was compared with calcium availability measured in nonseptic dogs. We further characterized a filterable cardiodepressant substance (FCS), which has been previously shown to be associated with LV depression in this model, to determine whether it produced changes in calcium metabolism similar to those found in sepsis. The results showed that calcium availability from the SR of septic dogs was not impaired. Furthermore, FCS was found in the 10,000- to 30,000-mol wt fraction of plasma and produced changes in PRC in canine trabeculae that were similar to those produced during sepsis. We conclude that, as assessed by PRC and RCC, SR calcium content and release are not impaired in sepsis.

scholarly journals Glucose-6-Phosphate Dehydrogenase Regulation in Anoxia Tolerance of the Freshwater Crayfish Orconectes virilis

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Benjamin Lant ◽  
Kenneth B. Storey
Keyword(s):  
Protein Kinase ◽  
Antioxidant Defense ◽  
Pentose Phosphate ◽  
Kinetic Properties ◽  
Freshwater Crayfish ◽  
Orconectes Virilis ◽  
Rate Determining Step ◽  
Flow Through ◽  
Glucose 6 Phosphate Dehydrogenase

Glucose-6-phosphate dehydrogenase (G6PDH), the enzyme which catalyzes the rate determining step of the pentose phosphate pathway (PPP), controls the production of nucleotide precursor molecules (R5P) and powerful reducing molecules (NADPH) that support multiple biosynthetic functions, including antioxidant defense. G6PDH from hepatopancreas of the freshwater crayfish (Orconectes virilis) showed distinct kinetic changes in response to 20 h anoxic exposure. Km values for both substrates decreased significantly in anoxic crayfish; Km NADP+ dropped from 0.015±0.008 mM to 0.012±0.008 mM, and Km G6P decreased from 0.13±0.02 mM to 0.08±0.007 mM. Two lines of evidence indicate that the mechanism involved is reversible phosphorylation. In vitro incubations that stimulated protein kinase or protein phosphatase action mimicked the effects on anoxia on Km values, whereas DEAE-Sephadex chromatography showed the presence of two enzyme forms (low- and high-phosphate) whose proportions changed during anoxia. Incubation studies implicated protein kinase A and G in mediating the anoxia-responsive changes in G6PDH kinetic properties. In addition, the amount of G6PDH protein (measured by immunoblotting) increased by ∼60% in anoxic hepatopancreas. Anoxia-induced phosphorylation of G6PDH could contribute to modifying carbon flow through the PPP under anoxic conditions, potentially maintaining NADPH supply for antioxidant defense during prolonged anoxia-induced hypometabolism.

The availability of calcium in three grasses

1957 ◽  
Vol 49 (4) ◽  
pp. 446-453 ◽  
Author(s):  
R. H. Armstrong ◽  
Brynmor Thomas ◽  
D. G. Armstrong
Keyword(s):  
Oxalic Acid ◽  
Experimental Animal ◽  
Acid Content ◽  
Calcium Content ◽  
Fibre Content ◽  
Total Calcium ◽  
Rye Grass ◽  
Grassland Plants ◽  
Calcium Availability

1. The availability of the calcium in three species of grass has been determined by a slaughter technique, using the rat as the experimental animal.2. The calcium in both timothy and perennial rye-grass was found to be more available than that in cocksfoot, the differences between timothy and cocksfoot, and between perennial rye-grass and cocksfoot being of a significant order.3. The grasses as a whole were found to be inferior to both the legumes and herbs in respect of calcium availability.4. The significance of the high faecal calcium values found in rats receiving the cocksfoot diets has been discussed.5. There was shown to be some indication of inverse relationships between fibre content and calcium availability, and between oxalic acid content and calcium availability.No single one of the nine grassland plants so far investigated has proved to have a calcium availability which, when taken in conjunction with total calcium content, would be in the least likely to induce symptoms of deficiency in an animal fed on that species alone.

scholarly journals The Rhizobium and calcium fertilizer application to peanut plant in dry land

2021 ◽  
Vol 913 (1) ◽  
pp. 012011
Author(s):  
A Farid Hemon ◽  
Sumarjan
Keyword(s):  
Root Nodules ◽  
Block Design ◽  
Leaf Tissue ◽  
Calcium Content ◽  
Fertilizer Application ◽  
Growth And Yield ◽  
Dry Land ◽  
Randomized Block Design ◽  
Randomized Design ◽  
Calcium Availability

Abstract One of the main problems of peanut planting in dry land is a lack of nitrogen and calcium availability. Efforts to increase the nitrogen and calcium availability for peanut farming in dry land is needed and one possible approach is by application of Rhizobium and calcium fertilizers. This research was conducted to determine the effect of the application of Rhizobium (Nodulin) and calcium fertilizers on growth and yield of peanut plants in dry land. Two experiments were conducted, one in a greenhouse using a completely randomized design and another experiment in the field using a randomized block design. The treatments were with the application of Nodulin, without Nodulin, with calcium fertilizer and without calcium fertilizer. The results showed that the application of calcium and Nodulin was able to increase the number of root nodules and peanut growth. Nodulin and calcium fertilizers increased the dry pod weight of 2.177 g per 6 m2 or 3.7 tons.ha-1. The application of Nodulin and calcium was also able to increase the nitrogen and calcium content of leaf tissue up to 18.9% and 20.9%, respectively.

VASCULAR CONNECTIVE TISSUE UNDER THE INFLUENCE OF THYROXINE

1961 ◽  
Vol 36 (2) ◽  
pp. 197-211 ◽  
Author(s):  
lb Lorenzen
Keyword(s):  
Connective Tissue ◽  
Vessel Wall ◽  
Aortic Wall ◽  
Calcium Content ◽  
Sodium Sulphate ◽  
Collagen Content ◽  
Histological Changes ◽  
Hexosamine Content ◽  
Healing Processes

ABSTRACT Biochemical and histological changes in the aortic wall of rabbits were demonstrated following injection of epinephrine and l-thyroxine during 2 weeks. The widespread gross and microscopic changes were accompanied by an increase in hexosamine content and uptake of 35S labeled sodium sulphate, and an increased calcium content, whereas the collagen content, assessed by determination of hydroxyproline, was reduced. Comparison with the effect of epinephrine injections alone showed that thyroxine intensified the damaging effect of epinephrine on the vessel wall and induced more pronounced mucopolysaccharide changes in the aortic wall, presumably acting as a link in the healing processes.

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