October/November 2015 Teacher's Guide Table of Contents
Probiotics: Good Bacteria, Good Health
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Probiotics: Good Bacteria, Good Health
The term probiotic refers to “…live strains of bacteria similar to the ones that live naturally in the human gut.” The microbiome is the name for all the bacteria living inside our body.
Different bacteria in the gut are essential to digestion, provide energy, back up the immune system and synthesize chemicals that our body can use.
Some foods containing probiotics include yogurt, sauerkraut, pickles, Kefir (a fermented milk drink), kimchee, kombucha, cottage cheese (with added probiotics), and buttermilk.
Probiotics are defined as “… live microorganisms administered in adequate amounts which confer beneficial health effects on the host.”
Probiotics provide chemical reactions that convert carbohydrate molecules into alcohols or acids as they release energy through the chemical reaction, fermentation.
Carbon dioxide and either lactic acid or ethanol are produced in bacterial fermentation, in addition to the energy.
It is thought that “… certain genetically modified probiotics can produce a hunger-suppressing compound which signals the brain to want less food. Other probiotics stimulate the release of a hormone called GLP-1 which also causes a reduction in food intake.”
Louis Pasteur began his research on killing bacteria using wine, which neighboring winemakers had found was turning sour. They asked him to help them find out why.
When mice are fed the bacterium, Lactobacillus rhamnosus, it was found that the mice had half the normal amount of a stress hormone called corticosterone in their brains. This is due to the fact that the bacteria secrete a neurotransmitter, GABA (gamma aminobutryric acid), which influences the brain as an anti-stress compound, travelling from the intestine to the brain via the vagus nerve.
With an increase in this particular bacterium in the gut of mice, there was a matching increase in a protein called brain-derived neurotrophic factor. This factor in turn increases the production of another chemical called serotonin which is involved in mood regulation, pain perception, and perception of hunger and satiety (feeling full). Dirt? Who Needs It? How Hydroponics Is Poised to Change the World
The article says the predicted world population in 2030 is 8–9 billion. The reason this is important, according to the article, is that the land available for agriculture may not be sufficient in 2030 to adequately feed that population.
“Hydroponics is the agricultural technique of growing plants in water instead of soil.”
The article says that most plants are made up of “72% water, 24% organic material and 4% inorganic material, such as nitrogen and phosphorus.”
The nutrient source for hydroponic plants is a water solution containing the chemical nutrients (ions) that plants require for growth.
Carbon dioxide and water are the essential chemicals for plant growth.
William Gericke, a scientist working at the University of California, Berkeley in the 1930s first coined the term.
According to the article, macronutrients are those chemicals that plants need in large amounts, while micronutrients are needed in smaller amounts.
Potassium, nitrogen, phosphorus, and calcium are the plant macronutrients listed in the article.
The pH of the solution is the condition important for nutrient delivery.
Growing plants hydroponically requires a light-controlled environment and water must flow constantly through the system, both of which are energy-intensive. One way to minimize this impact is to use solar panels (possibly as both the source of light and of energy to pump the water). Light in the Cellar of the Sea
Marine organisms emit light by
The light produced by the midshipman fish helps to hide it from prey. The glow “radiates from its belly and blends in with a hint of moonlight, masking the shadow and silhouette of the fish.”
Since red light does not penetrate very far beneath the surface of the ocean there is no red light to reflect off of the red fish so they appear black in the black water as do the black fish. These fish are not visible at depths associated with the twilight zone.
Red light has the longest wavelength, the least energy of visible light, and is filtered out first. Blue light, with the shortest wavelength, penetrates the ocean water best.
Based on Figure 1, Infrared and ultraviolet light fade away first.
“White objects appear white because they reflect all colors of light in the visible spectrum. Black objects appear black because they absorb all colors of light [in the visible spectrum].”
The three chemical substances required to produce bioluminescence are
The event that convinced Edith Widder to study bioluminescence was when she dove in a one-person submersible. During that dive she was so impressed by the bioluminescent light show that she decided to study the phenomenon.
When Karen Osborn gently pinched the nearly transparent worm it shot out tiny bombs that burst into brilliant green light. Swima bombiviridis is Latin for “green bomber.”
To detect water pollution, Dr. Widder mixes glowing bacteria with mud samples from the Indian River Lagoon in Florida. When the water is toxic the glowing solution is dimmer. The toxic substances in the water are killing the bacteria, which is indicated by the dimmer glow.
The mantis shrimp eyes
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