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Bacterial morphological plasticity refers to changes in the shape and size that bacterial cells undergo when they encounter stressful environments. Although bacteria have evolved complex molecular strategies to maintain their shape, many are able to alter their shape as a survival strategy in response to protist predators, antibiotics, the immune response, and other threats.
Sarcina cells, for example, are arranged in cubical pockets because cell division alternates regularly among the three perpendicular planes. Streptococcus spp. resemble a string of beads because division always occurs in the same plane. Some of these strings, for example, S. pneumoniae, are only two cells long. They are called diplococci.
Cell shape is generally characteristic of a given bacterial species, but can vary depending on growth conditions. Some bacteria have complex life cycles involving the production of stalks and appendages (e.g. Caulobacter) and some produce elaborate structures bearing reproductive spores (e.g. Myxococcus, Streptomyces).
(A) An early schizont with cluster of knobs at the center. Scale bar = 1 μm. Inset is the same image under light microscope. (B) A young trophozoite with knobs. Scale bar = 1 μm. (C) A close up of the cell membrane showing individual knobs. Scale bar = 200 nm. (D) A close up of a single knob. Scale bar = 75 nm. [1]
In microbiology, pleomorphism (from Ancient Greek πλέω-, pléō, "more", and -μορφή, morphḗ, form), also pleiomorphism, is the ability of some microorganisms to alter their morphology, biological functions or reproductive modes in response to environmental conditions.
The etymology of the word "morphology" is from the Ancient Greek μορφή (morphḗ), meaning "form", and λόγος (lógos), meaning "word, study, research". [2] [3]While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist ...
First described in 1961 (where they were simply termed "characteristic granules"), [2] they are solely found in Langerhans cells. [1] Although part of normal Langerhans cell histology, they also provide a mechanism to differentiate Langerhans cell histiocytoses (which are a group of rare conditions collectively known as histiocytoses ) from ...
An inverted microscope is a microscope with its light source and condenser on the top, above the stage pointing down, while the objectives and turret are below the stage pointing up. It was invented in 1850 by J. Lawrence Smith , a faculty member of Tulane University (then named the Medical College of Louisiana).