Name: magnetotactic and dna-resistant bacteria
Uploaded: 2025-07-28T10:50:19.000Z
Duration: 1 min 18 s
Channel: JoVE

Etki Alanı Bakterileri, özellikle manyetik ve radyasyona dirençli bakteriler olmak üzere olağanüstü özelliklere sahip bazı türler içerir. Magnetospirillum magnetotacticum ve Desulfovibrio magneticus gibi manyetik bakteriler tipik olarak tabakalı göllerin oksik-anoksik arayüzünün yakınında bulunur. Bu bakteri türleri manyetozomlara sahiptir. Bir manyetozom tipik olarak aerobik türlerde manyetitten veya anaerobik türlerde greigitten yapılmış parçacık zincirlerinden oluşur. Bu bakteriler manyetoaksi sergiler. Manyetozomları, hem Kuzey hem de Güney Yarımküre'de Dünya'nın jeomanyetik alanıyla aynı hizaya gelir ve onları oksik-anoksik geçiş bölgelerine yönlendirir. Radyasyon direnci, Deinococcales düzeninin üyeleri tarafından sergilenen dikkate değer bir özelliktir. Deinococcus radiodurans türü, 15.000 gri iyonlaştırıcı radyasyon dozunda hayatta kalabilir. DNA'sının hücre içindeki benzersiz toroidal düzenlemesi ve çok katmanlı bir hücre duvarı yapısı, radyasyon direncinde önemli bir rol oynar.

derin dallanmış bakteriler

Other Unique Bacteria

Manyetik bakteriler, magnetotaksis ad&#305; verilen y&#246;nlendirilmi&#351; bir hareket sergilerler; bu hareket, magnetozom ad&#305; verilen yap&#305;lar taraf&#305;ndan y&#246;nlendirilir. Magnetozomlar, ya manyetit (Fe_3O_4) ya da greigit (Fe_3S_4) i&#231;eren manyetik par&#231;ac&#305;klardan olu&#351;an zincirler &#351;eklindedir ve h&#252;cre zar&#305;n&#305;n i&#231;e &#231;&#246;k&#252;nt&#252;leri i&#231;inde yer alan bir protein iskeleti arac&#305;l&#305;&#287;&#305;yla lineer bi&#231;imde organize edilirler. Bu bakteriler, pusula ibresi gibi, kuzey&#8211;g&#252;ney y&#246;n&#252;ndeki manyetik alan &#231;izgilerine hizalan&#305;rlar. Genellikle mikroaerofilik ya da anaerobik olan bu bakteriler, tortularda ya da tabakala&#351;m&#305;&#351; g&#246;llerdeki oksik&#8211;anoksik ara y&#252;zey yak&#305;nlar&#305;nda bulunur. Aerobik t&#252;rler genellikle magnetozomlar&#305;nda manyetit i&#231;erirken, anaerobik t&#252;rler greigit i&#231;erir.
Bakteriyel magnetozomlar&#305;n ekolojik rol&#252; hen&#252;z tam olarak anla&#351;&#305;lamam&#305;&#351;t&#305;r; ancak bu yap&#305;lar, bakterilerin d&#252;&#351;&#252;k oksijenli b&#246;lgelerde kalmas&#305;n&#305; sa&#287;layarak se&#231;ici bir avantaj sa&#287;layabilir. Tortularda ve tabakala&#351;m&#305;&#351; g&#246;llerde derinlik artt&#305;k&#231;a oksijen seviyeleri genellikle azal&#305;r. D&#252;nya&#8217;n&#305;n manyetik alan&#305; her iki yar&#305;mk&#252;rede de g&#252;&#231;l&#252; bir dikey bile&#351;ene sahip oldu&#287;undan, magnetotaktik bakteriler bu alan &#231;izgilerine hizalanarak oksijenden uzakla&#351;mak i&#231;in a&#351;a&#287;&#305;ya do&#287;ru y&#252;zerler. Magnetozom bir pusula gibi i&#351;lev g&#246;r&#252;rken, kam&#231;&#305;l&#305; hareket oksijene kar&#351;&#305; kemotaktik bir yan&#305;tla kontrol edilir.
Manyetik bakteriler, magnetozomlar&#305;n&#305;n y&#246;nelimine ba&#287;l&#305; olarak farkl&#305; manyetik kutupla&#351;malar sergiler. Kuzey Yar&#305;mk&#252;re'de, kuzeye y&#246;nelen bakteriler a&#351;a&#287;&#305;ya do&#287;ru hareket ederken, G&#252;ney Yar&#305;mk&#252;re'de g&#252;neye y&#246;nelen bakteriler ayn&#305; &#351;ekilde a&#351;a&#287;&#305;ya do&#287;ru y&#252;zer.
&#199;o&#287;u manyetik bakteri Alphaproteobacteria s&#305;n&#305;f&#305;na ait olsa da, Gammaproteobacteria, Deltaproteobacteria ve Nitrospira grubunda da t&#252;rler tan&#305;mlanm&#305;&#351;t&#305;r. &#304;yi karakterize edilmi&#351; t&#252;rlerden biri olan Magnetospirillum magnetotacticum, hem kemooorganotrofik mikroaerofil bir bakteri olup hem de nitrat (NO_3 ^-) veya diazotmonoksit (N_2O) indirgemesi yoluyla anaerobik olarak b&#252;y&#252;yebilir. Bir di&#287;er t&#252;r olan Desulfovibrio magneticus, s&#252;lfat indirgeyen zorunlu bir anaerobdur. Magnetozomlar ayr&#305;ca k&#252;k&#252;rt oksitleyen bakterilerde ve mor olmayan k&#252;k&#252;rts&#252;z bakterilerde de g&#246;zlemlenmi&#351;tir.
Ayr&#305;ca, &#231;ok h&#252;creli magnetotaktik bakteriler de vard&#305;r. Bu Deltaproteobacteria t&#252;rleri, i&#231;i bo&#351; bir k&#252;re &#351;eklinde d&#252;zenlenmi&#351; 10&#8211;20 h&#252;crelik k&#252;meler olu&#351;turur. Zorunlu anaerob olmalar&#305;na ra&#287;men, metabolik yollar&#305; h&#226;l&#226; tam olarak ayd&#305;nlat&#305;lamam&#305;&#351;t&#305;r.
Deinococcus radiodurans, Deinococcales tak&#305;m&#305;na ait olup, radyasyona ve kurakl&#305;&#287;a kar&#351;&#305; son derece diren&#231;lidir; 15.000 Gy&#8217;ye kadar olan radyasyon dozlar&#305;na dayanabilir. Genellikle karotenoidler nedeniyle k&#305;rm&#305;z&#305; ya da pembe renktedir ve toprak, et, toz ve havadan izole edilmi&#351;tir. &#199;o&#287;u mutajene kar&#351;&#305; diren&#231;li olsa da, DNA delesyonlar&#305;na kar&#351;&#305; hassast&#305;r.
Bu bakterinin &#246;zg&#252;n DNA onar&#305;m sistemi, &#231;ok say&#305;da enzimi i&#231;erir ve radyasyon hasar&#305;ndan sonra etkili iyile&#351;me sa&#287;lar. D. radiodurans, DNA&#8217;s&#305;n&#305; toroidal (halka benzeri) bir yap&#305;da d&#252;zenler; bu da homolog rekombinasyonu kolayla&#351;t&#305;r&#305;r ve par&#231;alanm&#305;&#351; kromozomlar&#305;n yeniden birle&#351;tirilmesini m&#252;mk&#252;n k&#305;lar. Bu ola&#287;an&#252;st&#252; onar&#305;m yetene&#287;i, h&#252;crenin a&#351;&#305;r&#305; DNA hasar&#305;ndan sonra bile b&#252;y&#252;mesini ve b&#246;l&#252;nmesini s&#252;rd&#252;rmesini sa&#287;lar.

Derin dallanmış bakteriler

Manyetik bakteriler, magnetotaksis ad&#305; verilen y&#246;nlendirilmi&#351; bir hareket sergilerler; bu hareket, magnetozom ad&#305; verilen yap&#305;lar ...

Education

JoVE Core

Microbiology

Mikrobiyoloji

Unit

Birim

Microbial Diversity

Mikrobiyal Çeşitlilik

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

magnetotactic and dna-resistant bacteria

Magnetotactic bacteria move using Earth’s magnetic field, and some bacteria are known for extreme DNA repair. These unusual microbes show two very different survival strategies. One uses magnetic particles to guide movement. The other can recover after severe radiation damage.

Magnetotaxis is the directed movement seen in magnetic bacteria. It depends on magnetosomes, which are chains of magnetic particles made of magnetite (Fe₃O₄) or greigite (Fe₃S₄). A protein scaffold keeps these particles lined up inside membrane folds, and the cells then align with north–south magnetic field lines like a compass needle.

These bacteria are usually microaerophilic or anaerobic, so they live where oxygen is low. They are common near the oxic–anoxic interface in sediments and stratified lakes, where oxygen levels drop with depth. Aerobic species usually contain magnetite in their magnetosomes, while anaerobic species usually contain greigite. The magnetosome may help keep the cells in low-oxygen zones.

Earth’s magnetic field has a strong vertical component in both hemispheres. That helps magnetotactic bacteria swim downward, away from oxygen. The magnetosome acts like a compass, while flagellar movement is guided by a chemotactic response to oxygen. These bacteria also show different magnetic polarities. In the Northern Hemisphere, north-seeking bacteria move downward, and in the Southern Hemisphere, south-seeking bacteria do the same.

Most magnetic bacteria belong to the Alphaproteobacteria, but some are found in the Gammaproteobacteria, Deltaproteobacteria, and Nitrospira group. Magnetospirillum magnetotacticum is a chemoorganotrophic microaerophile that can also grow without oxygen by reducing nitrate (NO₃⁻) or nitrous oxide (N₂O). Desulfovibrio magneticus is a sulfate-reducing obligate anaerobe. Magnetosomes have also been seen in sulfur oxidizers and purple nonsulfur bacteria, and multicellular magnetotactic bacteria also exist.

These multicellular magnetotactic bacteria are Deltaproteobacteria that form groups of 10 to 20 cells in a hollow sphere. They are obligate anaerobes, but their exact metabolism is still unknown. Another unusual bacterium, Deinococcus radiodurans, is famous for surviving radiation and drying out. It can survive doses of 15,000 Gy and is often red or pink because of carotenoids. It is found in soil, meat, dust, and air.

D. radiodurans is resistant to most mutagens, but it is vulnerable to DNA deletions. Its DNA repair system uses multiple enzymes to rebuild damaged DNA after radiation exposure. The cell also arranges its DNA in a toroidal, or ring-like, structure. This shape supports homologous recombination and helps fragmented chromosomes be put back together. As a result, the cell can resume growth and division after extreme DNA damage.

Magnetotactic and DNA-Resistant Bacteria

three-domain system of life

How rRNA Reshaped Life's Domains

Ribosomal RNA, or rRNA, changed how scientists classify life. Sequence analysis showed three major groups of cells: eukaryotes, bacteria, and archaea. In 1978, Carl R. Woese proposed domains as a taxonomic level above kingdoms to separate these groups. Woese also showed that archaea and bacteria are not the same, even though they can look similar. The three domains differ in rRNA, membrane lipid structure, transfer RNA, and sensitivity to antibiotics. These differences helped scientists build...

microbial classification system

Naming and Ranking Microbes

Microbial classification organizes bacteria and archaea into ranked groups based on shared traits and evolutionary relationships. Scientists use phenotypic similarities, which are visible or measurable traits, and genotypic data, which comes from genetic information. The result is a hierarchy that helps place each organism in a clear taxonomic order. The ranking system starts with species and moves upward through genus, family, order, class, and finally domain. A species can include one or...

methods of classification and identification

methods-of-classification-and-identification

Bacterial ID Through Lab Tests

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modern molecular taxonomy

DNA Tools for Identifying Bacteria

DNA-based methods help scientists identify and compare bacteria with much greater precision. As sequencing becomes faster and less expensive, these tools are used in clinical, environmental, and evolutionary studies. They let researchers tell related strains apart and track how microbes spread. One important method is multilocus sequence typing, or MLST. It examines several housekeeping genes, which are essential chromosomal genes that support basic cell functions. About 450-base-pair...

applications of molecular taxonomy

Molecular Taxonomy in Bacterial Research

Molecular taxonomy in bacterial research uses DNA sequencing and DNA fingerprinting to classify bacteria more precisely. These molecular tools help scientists study bacterial diversity, evolutionary relationships, and ecological roles. They have changed how researchers identify and compare bacteria in both health and environmental studies. One major use of molecular taxonomy is resolving taxonomic ambiguities, or unclear classification cases. It can separate closely related bacteria that were...

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Proteobacteria Classes and Their Key Roles

Proteobacteria are a large and diverse phylum of Gram-negative bacteria. They have an outer membrane that contains lipopolysaccharides. Many of them use different ways to get energy, including phototrophy, chemolithotrophy, and heterotrophy. They live in soil, water, and host-associated environments. This phylum is divided into six classes: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Epsilonproteobacteria, and Zetaproteobacteria. Each class includes...

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Chlamydiae Life Cycle and Host Infection

Chlamydiae are bacteria that live inside eukaryotic host cells. The phylum Chlamydiae, also called Chlamydiota, contains a single order, Chlamydiales. These bacteria are obligate intracellular parasites, which means they must enter host cells to survive and grow. Members of this group are usually very small cocci, about 0.5 μm across. They also have reduced genomes, usually between 0.55 and 1 Mbp. This limited genome fits their highly specialized way of life and their dependence on host...

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Planctomycetes Cell Structure and Life Cycle

Planctomycetes are a group of gram-negative bacteria known for unusual cell structures and a distinctive life cycle. They are mainly placed in two orders, Planctomycetales and Brocadiales. Many cells show stalks or other appendages and often appear in rosette groups. A key feature of these bacteria is their cell envelope. Planctomycetes have an S-layer, a surface layer that is relatively uncommon in bacteria. They also divide by budding, which is different from the simple cell split seen in...

bacterial phylum verrucomicrobiota

Verrucomicrobiota Cell Structure and Traits

Verrucomicrobiota are a bacterial phylum with several recognized orders, and most species belong to Verrucomicrobiotales. Many members are aerobic or facultatively aerobic, which means they can use oxygen but may also grow without it. They can also ferment sugars. One exception is the genus Methylacidiphilum, which contains aerobic methanotrophs, bacteria that use methane and oxygen. These bacteria live in many different places. They are found in freshwater, marine habitats, forest soils, and...

bacterial phylum spirochaetes

Spirochete Shape, Motion, and Disease

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bacterial phylum cyanobacteria

Cyanobacteria and Oxygenic Photosynthesis

Cyanobacteria are oxygenic, phototrophic bacteria that helped change Earth&amp;#8217;s atmosphere from low in oxygen to oxygen-rich billions of years ago. They are also very diverse in shape and size. Some are unicellular, while others grow as filaments. Cell size can range from 0.5 µm to 100 µm. Scientists group cyanobacteria into five major types. Chroococcales are unicellular and divide by binary fission. Pleurocapsales are also unicellular, but they divide by multiple fission.

bacterial phylum actinobacteria

Actinobacteria: Soil Bacteria and Cheese

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bacterial phylum firmicutes

Firmicutes: Bacteria, Fermentation, and Spores

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bacterial phylum bacteroidota

Gut and Environment Bacteria in Bacteroidota

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anoxygenic phototrophic bacteria

Sulfur-Using Bacteria That Harvest Light

Anoxygenic phototrophic bacteria are light-harvesting bacteria that do not release oxygen during photosynthesis. They include purple sulfur bacteria, purple nonsulfur bacteria, green sulfur bacteria, green nonsulfur bacteria, heliobacteria, and Chloracidobacterium thermophilum. These groups belong to the Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Chlorobi, Chloroflexi, Firmicutes, and Acidobacteria lineages, and each group has its own habitat and way of using light. Purple...

hyperthermophilic bacteria

Heat-Loving Bacteria and Their Enzymes

Hyperthermophilic bacteria live in extreme heat and show unusual adaptations that help them survive. Several of these species come from the Domain Bacteria and are found in hot springs and hydrothermal vents. Their biology helps explain how life can function in very hot environments. Thermotoga species are rod-shaped, gram-negative, non-sporulating hyperthermophiles. They form a sheath-like outer layer called a toga. These bacteria ferment sugars or starch and produce lactate, acetate, carbon...

bacterial phylum tenericutes

Mycoplasmas and Wall-Less Bacteria

Mycoplasmas are wall-less bacteria in the phylum Tenericutes. This group includes the single class Mollicutes, a name that comes from the Latin mollis, meaning soft. These bacteria are among the smallest known. They are often called mycoplasmas because the genus Mycoplasma includes many well-known human pathogens. Mycoplasmas cannot stain gram-positive because they lack cell walls. Even so, they are related to the Firmicutes. They often live closely with animal or plant hosts. Their small...

other unique bacteria

Magnetotactic bacteria move using Earth’s magnetic field, and some bacteria are known for extreme DNA repair. These unusual microbes show two very different survival strategies. One uses magnetic particles to guide movement. The other can recover after severe radiation damage. Magnetotaxis is the directed movement seen in magnetic bacteria. It depends on magnetosomes, which are chains of magnetic particles made of magnetite (Fe₃O₄) or greigite (Fe₃S₄). A protein scaffold keeps these particles...

overview of archaea

Archaea Cell Structure and Metabolism

Archaea are a unique domain of life with cell structures and metabolic strategies that set them apart from bacteria and eukaryotes. They were named after the Archaean eon and are important for understanding both early life and modern biotechnology. One key feature of archaea is their membrane chemistry. Their membranes contain ether-linked isoprenoid lipids, which help them stay stable in extreme conditions such as high heat and chemical stress. Archaea also have RNA polymerases that are more...

diversity of archaea i

Archaea Extremes: Euryarchaeota

Euryarchaeota is a major phylum of Archaea, a domain of single-celled microorganisms. Archaea are grouped into five major phyla based on genetic and biochemical traits: Euryarchaeota, Crenarchaeota, Thaumarchaeota, Korarchaeota, and Nanoarchaeota. Among them, Euryarchaeota stands out for its wide range of shapes, metabolism, and habitat use. Members of this phylum can have rod or cocci shapes. Their metabolism may be strictly aerobic or strictly anaerobic, which lets them live in both...

diversity of archaea ii

New Archaea Phyla and Their Roles

Archaea are one of the three domains of life, and their diversity includes species that live in both extreme and moderate environments. For a long time, most known archaea were grouped into two major phyla: Euryarchaeota and Crenarchaeota. Recent molecular studies have added three more phyla to this picture: Thaumarchaeota, Nanoarchaeota, and Korarchaeota. Thaumarchaeota are mesophilic archaea, which means they live in moderate conditions. They are found in soils, lakes, and marine regions. A...

diversity of archaea iii

Crenarchaeota in Extreme Hot Springs

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diversity of archaea iv

How Hyperthermophilic Archaea Survive Heat

Hyperthermophilic archaea are heat-loving extremophiles that live at temperatures above 80°C. They are often found in hydrothermal vents and volcanic soils, where the heat can be higher than the boiling point of water. At these temperatures, the proteins, membranes, and DNA of most organisms would break down. These archaea survive because their cell membranes are built differently. Their membranes contain a monolayer of biphytanyl tetraether lipids, which helps resist thermal damage. This...

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Fungi Structure, Reproduction, and Roles

Fungi are eukaryotes that are more closely related to animals than to other eukaryotes. Their cell walls contain chitin, a polysaccharide that gives strength, and glucans, which add flexibility and support. Some fungi also use mannans and galactosans in place of, or along with, chitin. These features help fungi live in acidic places and survive high osmotic pressure. Fungi can be unicellular, like yeasts, or multicellular. In multicellular fungi, the body forms a mycelium, which is a branching...

fungal group zygomycota

Zygomycota: Spores, Hyphae, and Roles

Zygomycota are a former fungal group made up mostly of terrestrial molds that act as decomposers. Recent phylogenetic studies now place them in two major clades: Mucoromycota and Zoopagomycota. Mucoromycota includes many symbiotic species, while Zoopagomycota is made up mainly of parasitic and pathogenic fungi. These fungi have coenocytic hyphae, which are filaments without septa, or cross walls. That structure allows cytoplasm and organelles to move through the hyphae in one continuous stream.

fungal phylum microsporidia

Microsporidia Spores and Host Infection

Microsporidia are unicellular fungi that live as obligate intracellular parasites. They were first classified as protists, but phylogenetic, molecular, and structural evidence later linked them to the Chytridiomycota. These non-motile organisms infect many animal hosts, including humans, and depend heavily on the host cell to survive. Their cells are very small, usually 2 to 5 micrometers wide. Microsporidia form spores with a chitin shell, which helps them resist the outside environment. The...

fungal phylum ascomycota

Ascomycota: Sac Fungi and Their Spore Cycle

Ascomycota are sac fungi with a wide range of forms and roles. This fungal phylum includes unicellular yeasts and filamentous molds such as Aspergillus and Penicillium. They live in aquatic and terrestrial habitats and have major ecological and economic importance. A key feature of ascomycetes is the ascus, a sac-like structure that contains haploid ascospores. These fungi can reproduce sexually and asexually. Sexual reproduction starts with plasmogamy, the fusion of cytoplasm from two...

fungal phylum basidiomycota

Basidiomycota: Mushrooms, Spores, and Ecological Roles

Basidiomycota is a major group of fungi that includes mushrooms, puffballs, decomposers, symbionts, plant pathogens, and some edible species. These fungi matter in ecosystems, agriculture, and medicine. A key feature of this phylum is the basidium, a small club-shaped structure that makes basidiospores. Many basidiomycetes form visible fruiting bodies called basidiocarps. The life cycle starts when a haploid basidiospore germinates into monokaryotic mycelium. When two compatible mycelia fuse,...

overview of algae

Algae Structure, Habitats, and Reproduction

Algae are simple eukaryotic photoautotrophs that live in many habitats and show a wide range of body forms. They contain chlorophyll and carry out oxygenic photosynthesis. They belong to the kingdom Archaeplastida, which also includes red and green algae and land plants. Unlike other protists with chloroplasts from secondary endosymbiosis, red and green algae came from primary endosymbiotic events. Algae can look very different from one another. Some are large brown kelp in coastal waters,...

red algae

Red Algae Pigments, Shapes, and Uses

Red algae are phototrophic organisms found mostly in marine environments. Some species also live in freshwater or on land. They may be unicellular or multicellular, and some multicellular forms grow large enough to be seen easily. These algae contain chlorophyll a, but their chloroplasts do not contain chlorophyll b. Instead, they use phycobiliproteins, which are light-harvesting pigments like those found in cyanobacteria. The red color seen in many species comes from phycoerythrin, an...

green algae

Green Algae: Forms, Habitats, and Roles

Green algae are photosynthetic organisms with chlorophylls a and b in their chloroplasts. These pigments give them a green color. They differ from red algae because they lack phycobiliproteins, the pigments that produce red or blue-green tones in red algae. In pigment makeup, green algae are close to plants, and they share a close evolutionary relationship with them. Green algae belong to Phylum Chlorophyta in the Kingdom Archaeplastida. They are usually divided into two main groups:...

other algae

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overview of protists

Protist Diversity, Movement, and Survival

Protists are diverse eukaryotic microorganisms with many ways to move, eat, and survive. They do not have the specialized tissues of plants and animals or the chitinous cell walls of fungi. Their early split within Eukarya led to major structural, functional, and ecological diversity. Scientists group protists into supergroups based on genetic analysis and shared structures. These groups include Archaeplastida, Excavata, Amoebozoa, Rhizaria, Alveolata, and Stramenopiles. This classification...

diversity of protists i

Excavata Protists and Their Adaptations

Excavata protists show many different ways of living, from photosynthesis to parasitism. This group includes organisms that can use chemical energy, light, or both. Some also live in low-oxygen, or anaerobic, environments where they survive without normal oxygen-based metabolism. Among the main Excavata groups are diplomonads and parabasalids. These are flagellated protists, meaning they move with whip-like tails, and they lack mitochondria and chloroplasts. They often live in anoxic habitats,...

diversity of protists ii

Alveolates: Ciliates, Dinoflagellates, Apicomplexans

Alveolates are protists with tiny sacs called alveoli beneath the cell membrane. These sacs may help control water balance by limiting how much water moves in and out of the cell. In dinoflagellates, alveoli may also act like armor plates. The three main alveolate groups are ciliates, dinoflagellates, and apicomplexans. Ciliates move with cilia, which are short hair-like structures that can cover the whole cell or appear in rows or tufts. One well-known ciliate is Paramecium, which uses cilia...

diversity of protists iii

Rhizaria: Pseudopods, Tests, and Skeletons

Rhizaria are unicellular protists with threadlike pseudopodia, which are thin cytoplasmic extensions used for movement and feeding. Their amoeboid shape once caused taxonomic confusion, but molecular phylogenetics has since shown where they fit on the evolutionary tree. This group includes Chlorarachniophyta, Radiolaria, and Foraminifera, and each lineage has adapted to a different ecological niche and metabolic strategy. Chlorarachniophyta are unicellular phototrophic protists found in marine...

diversity of protists iv

Amoebozoa: Movement and Life Cycles

Amoebozoa are a diverse group of terrestrial and aquatic protists. They move and feed with lobe-shaped pseudopodia. This feature sets them apart from Rhizaria, which have threadlike pseudopodia. The group includes gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence also shows that Amoebozoa split from a lineage that later gave rise to fungi and animals. Gymnamoebas are free-living protists that live in water and soil. They move by amoeboid movement,...

key terms and concepts

Explore magnetotactic bacteria, magnetosomes, and how Deinococcus radiodurans repairs DNA after extreme radiation damage in this high school biology page.

Magnetotactic and DNA-Resistant Bacteria | 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

Magnetotactic and DNA-Resistant Bacteria

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