Nanobiology Notes

Perkinjes and Granules and Schwanns, oh my...

It's tempting to oversimplify things. Like neurons. It would be nice if there were one type of neuron, and all you needed to know about how neurons work could be clearly labelled on a diagram of that one type of neuron. Well, nature LOVES to specialize. So, before getting deeper into how neurons work, I thought it would be good to take a step back and get some vocabulary in place... The Basics From University of Washington's 'Neuroscience for kids': Neurons come in many different shapes and sizes. Some of the smallest neurons have cell bodies that are only 4 microns wide. Some of the biggest neurons have cell bodies that are 100 microns wide. Neurons are similar to other cells in the body because: Neurons are surrounded by a cell membrane. Neurons have a nucleus that contains genes. Neurons contain cytoplasm, mitochondria and other "organelles" . Neurons carry out basic cellular processes such as protein synth...

Neurotransmitters - molecular messages

You often hear about neurotransmitters in the news and in science magazines in a kind of off-hand way that assumes everyone must surely know what these things are. But, um, what are they, exactly? From Sandra Ackerman's book "Discovering the Brain" : To be recognized as a neurotransmitter, a chemical compound must satisfy six conditions: It must be synthesized in the neuron, stored there, released in sufficient quantity to bring about some physical effect; when administered experimentally, the compound must demonstrate the same effect that it brings about in living tissue; there must be receptor sites specific to this compound on the postsynaptic membrane, as well as a means for shutting off its effect, either by causing its swift decomposition or by reuptake, absorbing it back into the cell. OK, well, what about hormones? They're chemical messengers too - how are hormones different from neurotransmitters? A hormone, by definition, is a compound produced by an end...

Magnetoreception - a gift from Mars?

I've been finding lately that if you look deeply into just about any aspect of life it quickly becomes fascinating. Like migration, for instance... The story starts with something called 'magnetotactic bacteria' - bacteria that have DNA that creates tiny magnetite (Fe[sub]3[/sub]O[sub]4[/sub]) particles that can act as tiny compasses... From Magnetotactic bacteria Magnetites from magnetotactic bacteria MV-1 are elongated. The elongation adds to the magnetic pull of these tiny compasses and thus helps the bacteria locate sources of food and energy. This team of authors found that the elongation was accomplished by the addition of six faces, shown in red in the figure [above]. "The process of evolution on Earth has driven magnetotactic bacteria to make perfect little bar magnets, which differ strikingly from anything found outside biology," says coauthor Joe Kirschvink And it turns out that birds, sea turtles and salmon also have these tiny magnetite crysta...

Beta Rhythm (Music of the Mind)

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