E Coli cells or Microscopic Bacteria floating under microscope

Synura golden-brown alga. Scanning electron micrograph (SEM) of a single cell. The synurids are a small group of golden-brown algae, found mostly in freshwater. They are covered in silicate scales and spines. Synura occur as spherical colonies. Several scale types occur on the same cell, depending on their position.

"Leishmania mexicana parasites, light microscopy. L. mexicana is a protozoan that causes the tropical disease leishmaniasis, which is transmitted by the bites of infected sandflies. These are the motile promastigote forms of the parasite, which are injected into the blood by the sandfly's bite. Once inside the bloodstream they invade or are engulfed by phagocytic macrophage white blood cells, but are not destroyed, and instead hide from the immune system inside the cells. Thus hidden, the transform into the amastigote stage and reproduce, bursting from the cell to infect others. The amastigotes are then picked up the next time a sandfly bites and drinks blood, turn into the promastigote form, and the cycle continues. Leishmaniasis caused by L. mexicana is relatively mild, either causing an ulcer at the bite site or more widespread skin ulcers if the parasite spreads through the skin. The disease is typically self-limiting and heals over time, but persistent cases can be treated with pentavalent antimony drugs. Filmed with phase contrast illumination."

Light microscopy of a swarm of Euglena protozoa in pond water. Euglena is a single-celled plant-like protist with an oozing, ever-changing shape. Its bright green color comes from chloroplasts used in photosynthesis, as in plants. It propels itself with a single, hairlike flagellum located at its leading end. It is attracted to light, which it detects using its red eyespot located near the base of its flagellum. These specimens measure approximately 50 micrometres in length. Their movement has been slowed down due to evaporation of water on the microscope slide. Recorded under Nomarski differential interference contrasts illumination.

Light microscopy showing Vibrio cholerae bacteria, the species that causes the disease cholera. Cholera is an acute infection affecting the small intestines. It causes severe vomiting and diarrhoea, leading to dehydration which can be fatal. This species is water-borne, transmitted to humans through contaminated drinking water. There are millions of cases each year, and around 20-140,000 deaths as a result. Mild cases can be treated with rehydration solutions, more sever cases require intravenous fluids and antibiotics. Filmed in 2005.

Time-lapse light microscopy showing Vibrio cholerae bacteria, the species that causes the disease cholera, replicating. Cholera is an acute infection affecting the small intestines. It causes severe vomiting and diarrhoea, leading to dehydration which can be fatal. This species is water-borne, transmitted to humans through contaminated drinking water. There are millions of cases each year, and around 20-140,000 deaths as a result. Mild cases can be treated with rehydration solutions, more sever cases require intravenous fluids and antibiotics. Filmed in 2005.

Light microscopy showing dead and dying human sperm cells (spermatozoa) having been outside the body for a number of days. Sperm are mobile reproductive cells (gametes) which can fertilise the egg (female gamete) during sexual reproduction, and carry one set of chromosomes from one parent. Sperm can remain in the testes for around 74 days before dying, but once outside the body will typically only survive for a number of minutes unless preserved.

Different germs in the human intestines called microbiome,Bacteria Lactobacillus in human intestine,Beneficial healthy intestinal bacterium microflora,Gut bacteria

Medical visualization. Living bacteria animation.

Light microscopy showing dead and dying human sperm cells (spermatozoa) having been outside the body for a number of days. Sperm are mobile reproductive cells (gametes) which can fertilise the egg (female gamete) during sexual reproduction, and carry one set of chromosomes from one parent. Sperm can remain in the testes for around 74 days before dying, but once outside the body will typically only survive for a number of minutes unless preserved.

Light microscopy showing human sperm cells (spermatozoa) moving. Spermatozoa are mobile reproductive cells (gametes) which can fertilise the egg (female gamete) during sexual reproduction, and carry one set of chromosomes from one parent.

Bacterium Medical Background Abstract

Animated coloured scanning electron micrograph (SEM) of Pseudomonas aeruginosa, Gram-negative, aerobic, enteric, rod prokaryote (dividing). This bacterium produces a blue, Green pigment, pyocyanin, which characterizes the bluish pus produced by the infection. It is found in soil, water, skin flora, and most man-made environments throughout the world.