Hormogonium

Hormogonium

Hormogonia are motile filaments of cells formed by some cyanobacteria in the family Nostoceae.

Cyanobacteria differentiate into hormogonia when exposed to an environmental stress or when placed in new media.

Hormogonium differentiation is crucial for the development of nitrogen-fixing plant cyanobacteria symbioses, in particular that between cyanobacteria of the genus "Nostoc" and their hosts. In response to a hormogonium-inducing factor (HIF) secreted by plant hosts, cyanobacterial symbionts differentiate into hormogonia and then dedifferentiate back into vegetative cells after about 96 hours. Hopefully, they have managed to reach the plant host by this time. The bacteria then differentiate specialized nitrogen-fixing cells called heterocysts and enter into a working symbiosis with the plant.

Depending on species, Hormogonia can be many hundreds of micrometers in length and can travel as fast as 11 μm/s. They move via gliding motility, requiring a wet-able surface or a viscous substrate, such as agar for motion.


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  • Hormogonium — Hor mo*go*ni um, n. [NL., fr. Gr. ? a chain + ? generation.] (Bot.) A chain of small cells in certain alg[ae], by which the plant is propagated. [1913 Webster] …   The Collaborative International Dictionary of English

  • hormogonium — noun (plural hormogonia) Etymology: New Latin, from Greek hormos chain, necklace + New Latin gonium more at series Date: 1880 a portion of a filament in many cyanobacteria that becomes detached as a reproductive body …   New Collegiate Dictionary

  • hormogonium — hor·mo·go·ni·um (hôr mə gōʹnē əm) n. pl. hor·mo·go·ni·a ( nē ə) A part of a filament of a cyanobacterium that detaches and grows by cell division into a new filament.   [New Latin : Greek hormos, chain, necklace; See ser 2 in Indo European Roots… …   Universalium

  • hormogonium — noun A small, motile filament, formed by some cyanobacteria, that detaches and grows by cell division into a new filament …   Wiktionary

  • hormogonium — hor·mo·go·ni·um …   English syllables

  • hormogonium — …   Useful english dictionary

  • Cyanobacteria — Temporal range: 3500–0 Ma Had n Archean …   Wikipedia

  • hormospore — ˈhȯrməˌspō(ə)r noun Etymology: New Latin hormogonium + English spore : a terminally borne hormogonium in some blue green algae with cells modified in shape and having exceptionally thick walls …   Useful english dictionary

  • genə- — Also gen . To give birth, beget; with derivatives referring to aspects and results of procreation and to familial and tribal groups. Oldest form *g̑enə₁ , becoming *genə₁ in centum languages. Derivatives include kin, king, jaunty, genius,… …   Universalium

  • hormogonales — ˌhȯ(r)məgōˈnä(ˌ)lēz noun plural Usage: capitalized Etymology: New Latin, from hormogonium + ales : an order of filamentous blue green algae having the capacity to form hormogonia …   Useful english dictionary

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