Name: spirochete shape, motion, and disease
Uploaded: 2025-06-12T09:21:19.000Z
Duration: 1 min 30 s
Channel: JoVE

As espiroquetas são bactérias Gram-negativas, enroladas, classificadas no filo Spirochaetes. Os endoflagelos nas espiroquetas produzem um movimento semelhante ao do saca-rolhas, permitindo o movimento através de materiais ou tecidos viscosos. O gênero Spirochaeta inclui espiroquetas anaeróbicas e facultativamente aeróbicas que vivem livremente em água doce, sedimentos e oceanos. Espécies notáveis incluem Spirochaeta plicatilis de ambientes sulfídicos de água doce e marinhos. Cristispira é um gênero de espiroquetas que são encontradas no estilo cristalino de muitos moluscos bivalves como amêijoas, mexilhões e ostras. O gênero Treponema inclui espiroquetas anaeróbicas ou microaerofílicas que são comensais ou patógenos de humanos e animais, como Treponema denticola, comuns na cavidade oral humana. Muitas espécies do gênero Borrelia são patogênicas. Borrelia burgdorferi, por exemplo, causa a doença de Lyme, que é transmitida por carrapatos. Os gêneros Leptospira e Leptonema são espiroquetas estritamente aeróbicas que oxidam ácidos graxos de cadeia longa, como o ácido oleico, dos tecidos de seu hospedeiro ou do ambiente para apoiar seu crescimento. Leptospira interrogans é parasita em humanos e causa leptospirose.

filo bacteriano: spirochetes

Bacterial Phylum Spirochaetes

As espiroquetas, bact&#233;rias &#250;nicas do filo Spirochaetes, s&#227;o Gram-negativas, m&#243;veis, espiraladas, delgadas e flex&#237;veis. Habitam sedimentos aqu&#225;ticos e animais, sendo algumas causadoras de doen&#231;as como a s&#237;filis. As espiroquetas s&#227;o classificadas em oito g&#234;neros com base em habitat, patogenicidade, filogenia e caracter&#237;sticas morfol&#243;gicas.
Sua motilidade distintiva decorre de endoflagelos localizados no periplasma celular. Esses endoflagelos ancoram-se nos polos da c&#233;lula e se estendem ao longo de seu comprimento, envoltos por uma bainha externa flex&#237;vel. Quando os endoflagelos giram, geram tor&#231;&#227;o, fazendo com que a c&#233;lula se flexione e se mova com um padr&#227;o helicoidal, facilitando a penetra&#231;&#227;o em materiais viscosos ou tecidos. As espiroquetas s&#227;o frequentemente confundidas com espirilos, c&#233;lulas helicoidais em forma de bastonete com flagelos polares. Diferentemente das espiroquetas, os espirilos n&#227;o possuem bainha externa, endoflagelos nem motilidade helicoidal. Os espirilos s&#227;o mais r&#237;gidos e maiores, enquanto as espiroquetas s&#227;o finas (cerca de 0,5 &#956;m) e altamente flex&#237;veis.
O g&#234;nero Spirochaeta inclui espiroquetas de vida livre, anaer&#243;bias e facultativamente aer&#243;bias, encontradas em &#225;gua doce, sedimentos e oceanos. Spirochaeta plicatilis habita ambientes dulc&#237;colas e marinhos sulfidr&#237;cos, com feixes de endoflagelos ao redor de seu cilindro protoplasm&#225;tico espiralado. Spirochaeta stenostrepta, um anaer&#243;bio estrito presente em lamas ricas em H_2S, fermenta a&#231;&#250;cares em etanol, acetato, lactato, CO_2 e H_2.
O g&#234;nero Cristispira, exclusivo do estilo cristalino de moluscos como ostras e am&#234;ijoas, auxilia no processamento de alimentos em seus tratos digestivos. Encontrado em moluscos de &#225;gua doce e salgada, Cristispira ainda n&#227;o foi cultivado em laborat&#243;rio, e sua adapta&#231;&#227;o espec&#237;fica a esse habitat permanece incerta.
Espiroquetas anaer&#243;bias ou microaerof&#237;licas do g&#234;nero Treponema s&#227;o comensais ou pat&#243;genos de humanos e animais. Treponema pallidum, agente causador da s&#237;filis, &#233; extremamente fino (0,2 &#956;m) e apresenta morfologia ondulada e achatada. A microscopia de campo escuro &#233; comumente usada para detect&#225;-lo em les&#245;es sifil&#237;ticas.
Outras esp&#233;cies incluem T. denticola, encontrada na cavidade oral humana e associada &#224; doen&#231;a periodontal. Ela fermenta amino&#225;cidos produzindo acetato, CO_2, NH_3 e H_2S. T. saccharophilum reside no r&#250;men de ruminantes, fermentando polissacar&#237;deos vegetais, enquanto T. primitia e T. azotonutricium habitam o intestino de cupins, auxiliando na fermenta&#231;&#227;o de celulose, acetog&#234;nese e fixa&#231;&#227;o de nitrog&#234;nio.
O g&#234;nero Borrelia inclui pat&#243;genos como B. burgdorferi, causador da doen&#231;a de Lyme, transmitida por carrapatos. Destac&#225;vel por seu cromossomo linear, B. burgdorferi infecta humanos e animais. Outras esp&#233;cies de Borrelia causam doen&#231;as em aves e animais de cria&#231;&#227;o, tamb&#233;m transmitidas por carrapatos.
Os g&#234;neros Leptospira e Leptonema consistem em espiroquetas estritamente aer&#243;bias que oxidam &#225;cidos graxos de cadeia longa, como o &#225;cido oleico, para seu crescimento. As esp&#233;cies de Leptospira s&#227;o finas, espiraladas e geralmente encurvadas em forma de gancho em cada extremidade. O grupo inclui esp&#233;cies de vida livre (L. biflexa) e parasit&#225;rias (L. interrogans).
Cepas de L. interrogans infectam humanos e animais, com os roedores sendo os principais hospedeiros, embora c&#227;es e porcos tamb&#233;m possam ser portadores. Em humanos, a leptospirose &#233; a condi&#231;&#227;o mais comum causada por Leptospira, levando a danos renais e hep&#225;ticos, nefrite, icter&#237;cia e, potencialmente, insufici&#234;ncia renal ou morte. As bact&#233;rias penetram por membranas mucosas ou les&#245;es na pele durante o contato com animais infectados. Animais dom&#233;sticos, como c&#227;es, s&#227;o vacinados contra leptospirose como parte da vacina combinada contra cinomose&#8211;leptospira&#8211;hepatite.

Filo bacteriano: Spirochetes

As espiroquetas, bact&#233;rias &#250;nicas do filo Spirochaetes, s&#227;o Gram-negativas, m&#243;veis, espiraladas, delgadas e flex&#237;veis. Habitam ...

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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.

microbiology

Spirochete Shape, Motion, and Disease

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