Name: spirochete shape, motion, and disease
Uploaded: 2025-06-12T09:21:19.000Z
Duration: 1 min 30 s
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Le spirochete sono batteri Gram-negativi, arrotolati classificati nel phylum Spirochaetes.Gli endoflagelli nelle spirochete producono un movimento simile a un cavatappi, consentendo il movimento attraverso materiali viscosi o tessuti.Il genere Spirochaeta comprende spirochete anaerobiche e facoltativemente aerobiche che vivono libere in acqua dolce, sedimenti e oceani.Tra le specie degne di nota vi è la Spirochaeta plicatilis proveniente da ambienti solfidici d'acqua dolce e marini.Cristispira è un genere di spirochete che si trovano nello stile cristallino di molti molluschi bivalvi come vongole, cozze e ostriche.Il genere Treponema comprende spirochete anaerobi o microaerofile che sono commensali o patogeni dell'uomo e degli animali, come il Treponema denticola, comune nella cavità orale umana.Molte specie del genere Borrelia sono patogene. La Borrelia burgdorferi, ad esempio, causa la malattia di Lyme, che viene trasmessa dalle zecche.I generi Leptospira e Leptonema sono spirochete strettamente aerobiche che ossidano gli acidi grassi a catena lunga, come l'acido oleico, dai tessuti del loro ospite o dall'ambiente per sostenerne la crescita. La Leptospira interrogans è parassitaria nell'uomo e causa leptospirosi.

phylum batterico: spirochete

Bacterial Phylum Spirochaetes

Le spirochete, batteri unici appartenenti al phylum Spirochaetes, sono Gram-negativi, mobili, fortemente spiralizzati, sottili e flessibili. Abitano sedimenti acquatici, organismi animali e alcune specie sono responsabili di patologie come la sifilide. Le spirochete sono classificate in otto generi, sulla base dell&#8217;habitat, della patogenicit&#224;, della filogenesi e delle caratteristiche morfologiche.
La loro motilit&#224; distintiva deriva dagli endoflagelli, situati all&#8217;interno del periplasma cellulare. Gli endoflagelli si ancorano ai poli cellulari e si estendono lungo l&#8217;asse longitudinale della cellula, avvolti da un guaina esterna flessibile. Quando ruotano, generano una torsione che induce la flessione e il movimento della cellula in modo simile a un cavatappi, facilitandone la penetrazione in materiali viscosi o nei tessuti. Le spirochete sono spesso confuse con le spirille, cellule elicoidali a forma di bastoncello con flagelli polari. A differenza delle spirochete, le spirille non possiedono una guaina esterna, endoflagelli o motilit&#224; a cavatappi. Le spirille sono pi&#249; rigide e di dimensioni maggiori, mentre le spirochete sono sottili (circa 0,5 &#956;m) e altamente flessibili.
Il genere Spirochaetes comprende le spirochete anaerobiche o aerobiche facoltative a vita libera, presenti in acqua dolce, sedimenti e ambienti oceanici. Le spirochete plicatilis vivono in habitat dolci e marini ricchi di solfuri e sono caratterizzati da fasci di endoflagelli attorno al cilindro protoplasmatico spiralizzato. Le spirochete stenostrepta, anaerobia si trova in fanghi ricchi di H_2S, fermenta negli zuccheri producendo etanolo, acetato, lattato, CO_2 e H_2.
Il genere Cristispira, esclusivo dello stile cristallino di molluschi come vongole e ostriche, contribuisce all&#8217;elaborazione del cibo nel tratto digestivo di questi animali. Si trova in molluschi d&#8217;acqua dolce e marina, non &#232; stato mai coltivato in laboratorio, e la sua specifica adattabilit&#224; a questo habitat rimane poco compresa.
Le spirochete anaerobiche, o microaerofile del genere Treponema, sono commensali o patogeni di uomini e animali. Il treponema pallidum, l&#8217;agente eziologico della sifilide, &#232; insolitamente sottile (0,2 &#956;m) e presenta una morfologia ondulata piatta. Per rilevarla nelle lesioni sifilitiche si utilizza comunemente la microscopia in campo oscuro.
Altre specie includono T. denticola, presente nella cavit&#224; orale umana e associata a parodontopatie. Fermenta amminoacidi producendo acetato, CO_2, NH_3 e H_2S. Il T. saccharophilum si trova nel rumine dei ruminanti e fermenta polisaccaridi vegetali, mentre il T. primitia e il T. azotonutricium abitano l&#8217;intestino delle termiti, contribuendo alla fermentazione della cellulosa, all&#8217;acetogenesi e alla fissazione dell&#8217;azoto.
Il genere Borrelia comprende patogeni come B. burgdorferi e causa della malattia di Lyme, trasmessa dalle zecche. Caratterizzata da un cromosoma lineare, B. burgdorferi infetta sia gli esseri umani che gli animali. Altre specie di Borrelia provocano malattie in animali da allevamento e uccelli, trasmesse anch&#8217;esse da morsi di zecca.
I generi Leptospira e Leptonema includono spirochete strettamente aerobie che ossidano gli acidi grassi a catena lunga, come l&#8217;acido oleico, per crescere. Le specie di Leptospira sono sottili, finemente spiralizzate e tipicamente incurvate ad uncino a ciascuna estremit&#224;. Il gruppo comprende specie a vita libera (L. biflexa) e parassitarie (L. interrogans).
I ceppi di L. interrogans infettano uomini e animali, con i roditori come principali ospiti, sebbene anche cani e suini possano fungere da serbatoio. Nell&#8217;uomo, la leptospirosi &#232; la patologia pi&#249; comune causata da Leptospira, provoca danni a reni e fegato, nefrite, ittero e, potenzialmente, insufficienza renale o morte. I batteri penetrano attraverso le mucose o le lesioni cutanee durante il contatto con animali infetti. Gli animali domestici, come i cani, vengono vaccinati contro la leptospirosi nell&#8217;ambito di un vaccino combinato contro cimurro&#8211;leptospira&#8211;epatite.

Phylum Batterico: Spirochete

Le spirochete, batteri unici appartenenti al phylum Spirochaetes, sono Gram-negativi, mobili, fortemente spiralizzati, sottili e flessibili. Abitano ...

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spirochete shape, motion, and disease

Spirochetes are a group of gram-negative bacteria with a thin, flexible, tightly coiled shape. They live in aquatic sediments and in animals. Some species are harmless, while others cause diseases such as syphilis and Lyme disease.

A key feature of spirochetes is their movement. They use endoflagella, which are flagella located inside the periplasm, the space under the outer layer of the cell. These endoflagella attach at the cell poles and run along the length of the bacterium inside a flexible outer sheath. When they rotate, they twist the cell into a corkscrew-like motion that helps it move through thick liquids and tissues.

Spirochetes are often confused with spirilla. Spirilla are helical or rod-shaped cells with polar flagella, but they lack an outer sheath and endoflagella. They are also more rigid and larger. Spirochetes are much thinner, about 0.5 micrometers wide, and they bend easily.

Scientists divide spirochetes into eight genera based on habitat, pathogenicity, phylogeny, and other traits. The genus Spirochaeta includes free-living species that can live without oxygen or with little oxygen. These bacteria are found in freshwater, sediments, and oceans. Spirochaeta plicatilis lives in sulfidic freshwater and marine habitats, and its endoflagella form bundles around the coiled cell. Spirochaeta stenostrepta is an obligate anaerobe in H2S-rich muds. It ferments sugars and produces ethanol, acetate, lactate, CO2, and H2.

Cristispira is another genus. It lives in the crystalline style of mollusks such as clams and oysters and helps with food processing in their digestive tracts. It is found in both freshwater and marine mollusks, but it has not been cultured, so its special adaptation to this habitat is still unclear.

Treponema species are anaerobic or microaerophilic spirochetes that live as commensals or pathogens in humans and animals. Treponema pallidum causes syphilis and is extremely thin, about 0.2 micrometers wide, with a flat, wavy shape. Dark-field microscopy is often used to detect it in syphilitic lesions. Other species include T. denticola in the human mouth, where it is linked to gum disease, T. saccharophilum in the rumen of ruminants, and T. primitia and T. azotonutricium in termite guts, where they help with cellulose fermentation, acetogenesis, and nitrogen fixation.

The genus Borrelia includes important pathogens such as B. burgdorferi, which causes Lyme disease and spreads through tick bites. This species is unusual because it has a linear chromosome. Other Borrelia species cause disease in livestock and birds and are also transmitted by ticks.

Leptospira and Leptonema are strictly aerobic spirochetes that grow by oxidizing long-chain fatty acids such as oleic acid. Leptospira species are thin, finely coiled, and often hooked at both ends. The group includes free-living L. biflexa and parasitic L. interrogans. Rodents are the main hosts for L. interrogans, although dogs and pigs can also carry it. In humans, leptospirosis can damage the kidneys and liver and may cause nephritis, jaundice, renal failure, or death. The bacteria enter through mucous membranes or skin breaks after contact with infected animals. Dogs are vaccinated against leptospirosis with a combined distemper–leptospira–hepatitis vaccine.

Spirochete Shape, Motion, and Disease

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key terms and concepts

Explore spirochete structure, corkscrew motility, and major genera like Treponema, Borrelia, and Leptospira, plus diseases such as syphilis and Lyme disease.

Spirochete Shape, Motion, and Disease | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

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Spirochete Shape, Motion, and Disease

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