Diatoms, Diatoms, Chlamydomonas, Euglena, Cyanobacteria, Penicillium, Diatoms, Aspergillus
Plasmodium, Chlorella, Amoeba, Yeast, Paramecium, Sunworm.
Radiolaria, trumpet worm, Escherichia coli, Treponema pallidum, acidophilus thermophilus.
Azotobacter chromoglobosa, Spirulina Chlorella, Amoeba, Staphylococcus aureus.
Introduction:
The first single-celled organism appeared 3.5 billion years ago. Single-celled organisms belong to the lowest and most primitive animals in the whole animal kingdom. Including all archaea, eubacteria and many protozoa. According to the old classification, there are many animals, plants and fungi, most of which are multicellular organisms. Amoebas are counted as unicellular animals, but some of its species are counted as myxomycetes. Flagellated flagellates, such as euglena, are sometimes classified as unicellular algae or unicellular animals. In the new classification, all eukaryotic single-celled organisms are counted as protozoa.
Classification and generalization:
Single-celled organisms are mainly divided into nucleated and seedless single cells. Escherichia coli amplification 10000 times. Nucleated organisms such as paramecium are typical nucleated single-celled organisms. Nucleated unicellular organisms mainly include nucleus, cytoplasm and organelles.
It includes: mitochondria, Golgi apparatus, ribosome and cell membrane-this is an animal single cell. If it is a plant-type single cell such as red algae, it is composed of cell wall, nucleus and cytoplasm, and its organelles include mitochondria, Golgi apparatus, ribosomes, chloroplasts and cell membranes.
Although a seedless unicellular organism is called a seedless cell, it is not a cell with its nucleus removed, but a seedless cytoplasm mass existing in the evolution path, which is assumed by E.H.Haeckel( 1866) and is called a seedless protoplast mass (monera). Later, P.J.vanBeneden( 1875) applied this name to cells that disappeared before polar bodies (oocytes) appeared, and L.Auerbach( 1876) applied this name to cell clusters whose nuclei disappeared after general cell division.
Impact of ecological environment:
Although single-celled organisms are tiny, they are closely related to human life. Most unicellular organisms are part of plankton and fish's natural food. Paramecium has a certain effect on sewage purification. According to statistics, a paramecium can form about 60 food vacuoles per hour, and each food vacuole contains about 30 bacteria. Therefore, a paramecium can swallow about 43,000 bacteria every day. However, unicellular organisms are also harmful to human beings, such as plasmodium, amoeba dysentery and other parasites that endanger human health; The reproduction of some single-celled organisms in seawater may cause red tides.
Simply put, the relationship between single-celled organisms and humans can be divided into two aspects: benefits: bait, sewage purification and so on. Harmful: harmful to health, causing red tide, etc.
Technical application:
Single cell analysis is an interdisciplinary frontier field formed by the mutual penetration and development of analytical chemistry, biology and medicine. Various methods of single cell analysis include capillary electrophoresis, microfluidic chip, various optical microscopes (fluorescence microscope, focused fluorescence microscope, total internal reflection fluorescence microscope, multiphoton fluorescence microscope, fluorescence correlation microscope, near-field scanning optical microscope, etc. ), scanning electrochemical microscope, mass spectrometry imaging, atomic force microscope, scanning tunneling microscope image analysis, Hadamard transform microscopy and imaging, tumor electrochemistry and immunoassay, kinetic analysis, fluorescence and luminescence probes, etc.