Trichophyton interdigitale hyphae on human skin; enhanced SEM. SEM Magnification x8750.
Gingivitis. Coloured scanning electron micrograph (SEM) of a large number of bacteria (red) in the gingiva (gums) of a human mouth. The most common form of gingivitis, inflammation of the gum tissue, is in response to bacterial overgrowth that causes plaques (biofilms) to form on the teeth. Magnification: x5000, when printed 10 centimetres wide.
How herd immunity works: HPV vaccine lowers infection rate for all
Researchers were surprised by the findings having expected that a larger portion of the population, including boys, would need vaccination to see herd immunity.
Diatoms, coloured scanning electron micrograph (SEM). The diatoms are a group of photosynthetic, single-celled algae containing about 10,000 species. They form an important part of the plankton at the base of the marine and freshwater food chains. The characteristic feature of diatoms is their intricately patterned, glass-like cell wall, or frustule.
Foraminifera, coloured scanning electron micrograph (SEM). Those seen here include Elphidium crispum (purple), Ammonia beccarii (green), and Massilina secans (light blue). Foraminifera are marine single-celled marine protozoa that construct and inhabit a calcium carbonate shell composed of several chambers. These are usually penetrated by pores through which the cellular content is extruded to catch their prey. These specimens were obtained from cold waters.
Swimming with salmonella
It’s summer and thus time for the National Resources Defense Council’s annual report on the state of the nation’s beaches. In other words, where you enjoy a nice, safe dip and where the scariest menaces in the water are not big, bad sharks.
Rather, they’re tiny, terrible, teeming pathogens like salmonella bacteria, pictured above invading a cultured human cell in this false-colored micrograph from the National Institute of Allergy and Infectious Diseases.
Salmonella are indicator bacteria, a microbe used to detect and estimate the level of fecal contamination in water. A gram of human feces contains approximately 100 billion bacteria, not to mention pathogenic viruses, protozoa and parasites. Exposure to salmonella (which can come as well from tainted food or certain animals) can cause a host of ailments, from gastrointestinal disorders to typhoid fever.
The NRDC’s report was not encouraging. It found that the number of days that beaches around the country were closed or under health advisories reached 23,481 last year, slightly better than the previous year but still the third-highest total in the report’s 22-year history.