Image: Ca2+ flux across the inner mitochondrial membrane regulates cell bioenergetics, cytoplasmic Ca2+ signals and activation of cell death pathways. Ca2+ uptake from the cytoplasm is driven by the electrochemical gradient generated during ATP production, mediated by a Ca2+ ion channel called the mitochondrial Ca2+ uniporter.
Most healthy cells rely on a complicated process to produce the fuel ATP. Knowing how ATP is produced by the cell’s energy storehouse – the mitochondria — is important for understanding a cell’s normal state, as well as what happens when things go wrong, for example in cancer, cardiovascular disease, neurodegeneration, and many rare disorders of the mitochondria.
Two years ago, Kevin Foskett, PhD, professor of Physiology at the Perelman School of Medicine, University of Pennsylvania, and colleagues discovered that fundamental control of ATP production is an ongoing shuttle of calcium to the mitochondria from another cell compartment. They found that mitochondria rely on this transfer to make enough ATP to support normal cell metabolism.
Foskett’s lab and the lab of colleague Muniswamy Madesh, PhD, at Temple University, discovered last month an essential mechanism that regulates the flow of calcium into mitochondria, described in the October 26 issue of Cell. They found that the mitochondrial protein MICU1 is required to establish the proper level of calcium uptake under normal conditions.
In a new paper out this week in Nature Cell Biology, the same Penn-Temple team describe a new protein and its function. Like MICU1, this new protein, MCUR1, interacts physically with MCU, the uniporter calcium ion channel within the mitochondria. Calcium uptake is driven by a voltage across the inner mitochondrial membrane and mediated by the calcium-selective ion channel called the uniporter.
“But this newly described protein, MCUR1, has the opposite role as MICU1,” notes Foskett. “It seems to be a subunit that, together with MCU, is required for a functional uniporter calcium channel.”
Many cell plasma membrane ion channels also have subunits that are required for those channels to work. Before this paper, there was no realization that this mitochondrial channel, MCU, did as well.
Maintaining the correct levels of calcium in the mitochondria plays an important role in cellular physiology: Calcium flux across the inner mitochondrial membrane regulates cell energy production and activation of cell-death pathways, for example. In MICU1’s absence mitochondria become overloaded with calcium, generating excessive amounts of reactive oxygen molecules and eventually cell death. In contrast, in the absence of MCUR1, mitochondria cannot take up enough calcium. This also has detrimental effects: the cells cannot make enough ATP and they activate autophagy, a mechanism in which cells “eat themselves” to provide sufficient nutrients for survival
Both papers deal with the function of the uniporter, the calcium channel in the inner membrane of mitochondria that lets calcium get into the mitochondrial matrix where it can do good things like promote ATP synthesis and healthy bioenergetics, or bad things, like mitochondrial-mediated cell death, apoptosis and necrosis. …
By mass, calcium is the fifth-most-abundant element in the human body. It is a common cellular ionic messenger with many functions and also serves as a structural element in bone. The average human skeleton contains about 2.2 lbs (1 kg) of calcium. Using the following link you can compare nutrients in different foods: http://www.healthaliciousness.com/nutritionfacts/nutrition-facts-compare.php
Top 21 foods naturally highest in the nutrient, Calcium
1. Dried savory ( 2132 mg of calcium per100 gram serving )
2. Dried basil (2113 mg per 100 g )
3. Dried Whey acid ( 2054 mg per 100 g )
4. Dried Marjoram ( 1990 mg per 100 g )
5. Dried Thyme ( 1890 mg per 100 g )
6. Dried Dill weed ( 1784 mg per 100 g)
7. Celery seed ( 1767 mg per 100 g )
8. Ground sage ( 1652 mg per 100 g )
9. Sisymbrium Sp. Seeds Whole Dried ( 1633 mg per 100 g )
10. Smelt Dried, Alaska Native ( 1600 mg per 100 g )
11. Dried Oragano ( 1576 mg per 100 g )
12. Dill Seed ( 1516 mg per 100 g )
13. Dried Spearmint ( 1488 mg per 100 g )
14. Dried Parsley ( 1468 mg per 100 g )
15. Poppy seeds ( 1448 mg per 100 g )
16. Parmesan Cheese ( 1376 mg of calcium per 100 g)
17. Dried Chervil ( 1346 mg per 1oo g)
18. Dried Rosemary ( 1280 mg per 1oo g)
19. Dried Coriander Leaf ( 1246 mg per 100 g)
20. Cheese, in general ( 1220 mg calcium per 100 g)
21. Fennel Seed ( 1196 mg per 100 g)
Some others you may have wondered about:
Dried Alaskan Whitefish ( 810 mg / 100 g ), Beef: ( 485 mg / 100 g), Chicken ranges from 15 mg to 48 mg /100g … well 88 mg/100 g if you eat boiled chicken feet. But wait, there is more to this story. There are actually big differences in nutrient contents, even in the same food. Could you find beef with as much calcium as fennel seeds? That seems possible if the seeds are grown in depleted soil and have 1,000 times less calcium than they should. According to the Food and Ag Organization of the UN:
Nutrient contents in foods can vary significantly because:
- of environmental, genetic and processing influences such as feed, soil, climate, genetic resources (varieties/cultivars, breeds), storage conditions, processing, fortification and market share;
- each country has its own consumption pattern resulting in country-specific foods, recipes and brand-name foods (commercial foods with the same brand-name can have varying composition due to taste or fortification regulations across borders)
- food biodiversity highly influences the composition of foods: nutrient values may vary up to 1000 times among different varieties of the same foods. This means that the nutrient content of foods can vary as much among foods as among varieties of the same food.
I need energy. Perhaps adding some calcium will help. Time for dried basil! I’m not sure if I like savory… or even if I’ve ever tried it. Same with “whey acid” and chervil.
For you gardeners, if you have less than 40% calcium in your soil, here’s a page that says you should add some:
- Limestone- Calcium Carbonate (CaCO3). This is the most common form of calcium found in garden centers. Unless you have very low magnesium levels, do NOT use dolomitic lime, as it contains around 6% magnesium. Calcitic Lime is best. However, Calcium Carbonate will raise pH. So if you already have a high ph, stay away from lime.
- Gypsum- Calcium Sulfate. Gypsum, for reasons I don’t really understand but hear repeated all the time, will not raise soil pH like lime will. This is a great source of calium for those with high pH and low calcium availability.
I’d need an atomic absorption spectrophotometer for my garage laboratory.
… For your soil sample to yield meaningful test results, it should represent your entire field or garden site. From each of 10-20 locations throughout the garden, avoiding unusual spots such as wet areas or shaly knobs, take trowel full of soil from the top 6 – 8 inches. Place these in a clean plastic bucket. Mix the sample thoroughly with a plastic or wooden tool. Avoid touching the soil with your hands or an iron tool. Take your sample for testing from this. For a laboratory test you’ll need about one pound. Soil tests are most useful if we can observe test results from the same field over several years. Sampling during the same time of year and using the same lab or testing methods will assure the most consistent results.
Below are actual test results from two different soil samples, followed by a discussion of what this means for the gardener. Soil # 1 is from our research farm in northern New Mexico, within the Rio Grande floodplain. Soil #2 is from our northeast trial garden, which is in a forest clearing in southern Maine that was pasture over 80 years ago but had since grown back to pine forest (before being logged).
Soil Test Comparison Soil #1 Soil #2 Relative Nutrient Level (VH=Very High, H=High
% Organic Matter 1.9 9.9 (with raw
4.5 (minus raw
pH 7.9 6.2 Cation Exchange
17.0 9.1 Potassium (K)(ppm) 1055 141 VH (soil #1)
H (soil #2)
Magnesium (Mg)(ppm) 340 137 M (soil #1)
H (soil #2)
Calcium (Ca)(ppm) 2209 1300 M (soil #1)
H (soil #2)
% Base Saturation Potassium 15.9 4.0 Magnesium 16.5 12.5 Calcium 64.9 71.4 Phosphorus (P1)
no result 52 VH (soil #2) Phosphorus (P2)
VH (both soils)
… The cation nutrients (Ca, Mg, K) are expressed in parts per million (ppm). If you multiply ppm by 2, you will get the approximate number of pounds/acre of the nutrient (in the top 6 inches of soil).