Name: actinobacteria: soil bacteria and cheese
Uploaded: 2025-06-06T07:56:35.000Z
Duration: 1 min 30 s
Channel: JoVE

Aktinobakteriler, coryneform, propiyonik asit bakterileri, mikobakteriler ve aktinomisetler dahil olmak üzere çeşitli Gram pozitif bakteri grubudur ve yüksek G+C DNA içeriği ile ayırt edilirler. Korineform bakteriler, kopma bölünmesi nedeniyle düzensiz, sopa şeklinde veya V şeklinde düzenlemelere sahip aerobik, hareketsiz çubuklardır. Ana türler arasında patojenik Corynebacterium, difteriae, ve Arthrobacter — çubuk ve kok formları arasında geçiş yapabilen bir toprak bakteri cinsi bulunur. Propionibacterium, gibi propiyonik asit bakterileri, laktik asidi fermente eden, karbondioksit ve propiyonik asit üreten anaeroblardır. Mikobakteriler genellikle toprakta bulunur; çoğu zararsızdır, ancak Mycobacterium tuberculosis, gibi bazıları önemli insan patojenleridir. Mycobacterium tuberculosis yavaş büyüyen bir türdür, ancak Mycobacterium cinsi ayrıca Mycobacterium smegmatis gibi hızlı büyüyen türleri de içerir. Eşsiz özellikleri arasında hücre duvarlarındaki mikolik asitler ve dallanma veya filamentli büyüme geçirme yeteneği bulunur. Actinomycetes, misel ve kurumaya dirençli sporlar oluşturan filamentli ve aerobik bakterilerdir. Farklı bir cins olan Streptomyces, antibiyotik üretimi ile tanınır.

bakteri filumu: actinobacteria

Bacterial Phylum Actinobacteria

Koryneform bakteriler, Gram-pozitif, aerobik, hareketsiz ve basiller olup; d&#252;zensiz, topuz &#351;eklinde veya V &#351;eklinde dizilimler sergiler. Bu V &#351;ekli, &#231;&#305;tlamal&#305; (snapping) b&#246;l&#252;nme ad&#305; verilen bir mekanizmayla olu&#351;ur; i&#231; h&#252;cre duvar&#305; &#231;apraz duvar&#305; olu&#351;tururken, d&#305;&#351; duvar sa&#287;lam kal&#305;r ve bir taraftan y&#305;rt&#305;larak yavru h&#252;crelerin d&#305;&#351;a do&#287;ru b&#252;k&#252;lmesine neden olur.
Ba&#351;l&#305;ca cinsler Corynebacterium ve Arthrobacter&#8217;dir. Corynebacterium, saprofitik t&#252;rlerden patojen t&#252;rlere kadar geni&#351; bir t&#252;r &#231;e&#351;itlili&#287;ine sahiptir; bunlar aras&#305;nda Corynebacterium diphtheriae gibi hastal&#305;k etkenleri de bulunur. Buna kar&#351;&#305;l&#305;k, esas olarak toprakta bulunan Arthrobacter, &#231;omak (basil) ve kok formu aras&#305;nda ge&#231;i&#351; yapan bir geli&#351;im d&#246;ng&#252;s&#252; sergiler. Baz&#305; koryneform bakteriler de kok benzeri h&#252;creler geli&#351;tirebilse de, Corynebacterium t&#252;rleri genellikle &#231;omak ucu kal&#305;nla&#351;m&#305;&#351; (&#231;omak-u&#231;lu veya "&#231;omak-topuz" &#351;eklinde) bir morfoloji g&#246;sterirken, Arthrobacter bu a&#231;&#305;dan daha az belirgin bir yap&#305;ya sahiptir.
Arthrobacter t&#252;rleri spor olu&#351;turmamalar&#305;na ra&#287;men, kurakl&#305;&#287;a ve a&#231;l&#305;&#287;a kar&#351;&#305; son derece diren&#231;lidir. Metabolik olarak &#231;ok y&#246;nl&#252;d&#252;rler; herbisitler, kafein, nikotin ve fenoller gibi bile&#351;ikleri par&#231;alayarak toprak ekosistemlerinde kilit rol oynarlar.
Propiyonik asit bakterileri (Propionibacterium), ilk kez &#304;svi&#231;re peynirinde tan&#305;mlanm&#305;&#351;t&#305;r; burada fermantasyonla CO_2 olu&#351;turarak deliklerin olu&#351;umuna ve propiyonik asit &#252;retimiyle kendine &#246;zg&#252; lezzetin ortaya &#231;&#305;kmas&#305;na neden olurlar. Bu Gram-pozitif anaerobikler; laktik asit, karbonhidratlar ve polihidroksi alkolleri fermente ederek propiyonik asit, asetik asit ve CO_2 &#252;retir.
&#304;svi&#231;re peyniri &#252;retiminde Propionibacterium, Streptococcus ve Lactobacillus taraf&#305;ndan p&#305;ht&#305; olu&#351;umu s&#305;ras&#305;nda &#252;retilen laktat&#305; kullanarak ikincil fermantasyona kat&#305;l&#305;r. P&#305;ht&#305; s&#252;z&#252;ld&#252;kten sonra bu bakteriler &#231;o&#287;al&#305;r ve CO_2 &#252;retir; gaz, zay&#305;f b&#246;lgelerde birikerek peynirin deliklerini olu&#351;turur.
Ayr&#305;ca Propionigenium, ili&#351;kili olmayan ba&#351;ka bir bakteri olup, s&#252;ksinat fermantasyonuyla propiyonat &#252;retir ve bu, enerjetik olarak &#246;nemli bir metabolik s&#252;reci temsil eder.
Mikobakteriler, genellikle zarars&#305;z toprak bakterileridir; ancak Mycobacterium cinsindeki baz&#305; t&#252;rler insanlarda hastal&#305;k yapan &#246;nemli patojenlerdir. &#214;rne&#287;in Mycobacterium tuberculosis, t&#252;berk&#252;loz hastal&#305;&#287;&#305;na neden olur. Bu &#231;omak (basiller) &#351;eklindeki bakteriler, mikolik asit i&#231;eren h&#252;cre duvarlar&#305; nedeniyle (asidorezistans) asit-fast &#246;zelliktedir; bu kompleks lipidler, h&#252;cre duvar&#305;na vaks benzeri, hidrofobik bir yap&#305; kazand&#305;r&#305;r. Bu y&#252;zden Gram boyas&#305;yla iyi boyanmazlar ve Ziehl&#8211;Neelsen asit-fast boyas&#305; kullan&#305;l&#305;r; bu y&#246;ntemde asit-fast bakteriler k&#305;rm&#305;z&#305; rengi korurken, di&#287;erleri ise mavi g&#246;r&#252;n&#252;r.
Mikobakteriler pleomorfik olabilir ve bazen dallanm&#305;&#351; yap&#305;lar olu&#351;tururlar; ancak aktinomisetler gibi ger&#231;ek miselyum geli&#351;tirmezler. Yava&#351; b&#252;y&#252;yen t&#252;rler (M. tuberculosis, M. avium, M. bovis) ile h&#305;zl&#305; b&#252;y&#252;yen t&#252;rler (M. smegmatis, M. chelonae) olarak s&#305;n&#305;fland&#305;r&#305;l&#305;rlar. M. tuberculosis gibi yava&#351; b&#252;y&#252;yenler koloni olu&#351;turmak i&#231;in uzun ink&#252;basyon s&#252;releri gerektirir ve y&#252;ksek lipid i&#231;eri&#287;i nedeniyle koloni yap&#305;lar&#305; s&#305;k&#305;, buru&#351;uk ve hidrofobik olur.
Beslenme a&#231;&#305;s&#305;ndan, mikobakteriler basit mineral tuzlar&#305; ortam&#305;nda, amonyak kayna&#287;&#305; olarak kullan&#305;larak ve gliserol veya asetat gibi karbon kaynaklar&#305;yla aerobik olarak b&#252;y&#252;r. Ancak M. tuberculosis, lipidler ve ya&#287; asitleri i&#231;eren ortamlarda daha iyi geli&#351;ir. Vir&#252;lans&#305;, kordon fakt&#246;r&#252; ad&#305; verilen bir glikolipid taraf&#305;ndan olu&#351;turulan &#351;erit benzeri h&#252;cre k&#252;meleri ile ili&#351;kilidir.
Baz&#305; mikobakteriler karotenoid pigmentler &#252;retir ve bu durum kimliklendirme i&#231;in kullan&#305;l&#305;r. Bunlar; pigment &#252;retmeyen (M. tuberculosis, M. bovis), fotochromogenik (&#305;&#351;&#305;kta pigment olu&#351;turan, &#246;rn. M. parafortuitum) veya skotochromogenik (karanl&#305;kta bile pigment &#252;reten, &#246;rn. M. gordonae) olabilir. Karotenoidlerin, tekil oksijenin neden oldu&#287;u oksidatif hasara kar&#351;&#305; koruma sa&#287;lad&#305;&#287;&#305; d&#252;&#351;&#252;n&#252;lmektedir.
Aktinomisetler, toprakta yayg&#305;n olarak bulunan filament&#246;z, aerobik, Gram-pozitif bakterilerdir. Bir&#231;o&#287;u kurakl&#305;&#287;a dayan&#305;kl&#305; sporlar olu&#351;turan geli&#351;im d&#246;ng&#252;lerine sahiptir. B&#252;y&#252;meleri, filamanlar&#305;n uzamas&#305; ve dallanmas&#305; ile ger&#231;ekle&#351;ir ve bu durum mantar benzeri miselyum olu&#351;turur. Besin maddelerinin s&#305;n&#305;rl&#305; oldu&#287;u ko&#351;ullarda, y&#252;zeye do&#287;ru uzanan havaya y&#246;nelmi&#351; hifalar (aerial hyphae) geli&#351;ir ve bu yap&#305;lar farkl&#305;la&#351;arak sporlar (konidiyumlar veya egzosporlar) olu&#351;turur. Bu sporlar &#231;evresel stres ko&#351;ullar&#305;na dayan&#305;kl&#305; olup, hem hayatta kalma hem de yay&#305;l&#305;m amac&#305;yla g&#246;rev yaparlar.
Bu grup i&#231;indeki en &#246;nemli cins, 500'den fazla t&#252;rle Streptomyces&#8217;tir. Streptomyces filamanlar&#305; (0.5&#8211;1.0 &#956;m &#231;ap&#305;nda), u&#231;tan b&#252;y&#252;r ve s&#305;k dallanarak yo&#287;un miselyum olu&#351;turur. Koloniler olgunla&#351;t&#305;k&#231;a, sporofor ad&#305; verilen hava filamanlar&#305; geli&#351;ir ve konidiyum ad&#305; verilen sporlar &#252;retir. Bacillus ve Clostridium&#8217;daki endosporlar&#305;n aksine, konidiyumlar sporoforlar i&#231;inde &#231;apraz duvar b&#246;l&#252;nmesi ile olu&#351;ur.
T&#252;r s&#305;n&#305;fland&#305;rmas&#305;, hava filamanlar&#305; ve spor yap&#305;lar&#305;ndaki varyasyonlara dayan&#305;r. Konidiyumlar ve sporoforlar s&#305;kl&#305;kla pigmentlidir ve bu durum kolonilere ay&#305;rt edici renkler kazand&#305;r&#305;r. Olgun koloniler kompakt, pigmentli ve tozlu g&#246;r&#252;n&#252;ml&#252;d&#252;r, bu da Streptomyces kolonilerini agar plaklar&#305;nda kolayca tan&#305;nabilir h&#226;le getirir.

Bakteri filumu: Actinobacteria

Koryneform bakteriler, Gram-pozitif, aerobik, hareketsiz ve basiller olup; d&#252;zensiz, topuz &#351;eklinde veya V &#351;eklinde dizilimler sergiler. Bu ...

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actinobacteria: soil bacteria and cheese

Actinobacteria include several gram-positive bacteria that are common in soil and food production. This group includes coryneform bacteria, propionic acid bacteria, mycobacteria, and actinomycetes. Each group has a different shape, growth pattern, and role.

Coryneform bacteria are aerobic, nonmotile rods that often look irregular, club-shaped, or V-shaped. Their V-shape comes from snapping division. In this process, the inner cell wall forms the cross-wall first, while the outer wall stays intact until it breaks on one side, which bends the daughter cells apart.

The main coryneform genera are Corynebacterium and Arthrobacter. Corynebacterium includes species that range from harmless saprophytes to pathogens such as Corynebacterium diphtheriae. Arthrobacter is found mainly in soil and can switch between rod and coccus forms during its life cycle. It is also very resistant to drying and starvation, even though it does not form spores. Arthrobacter can break down herbicides, caffeine, nicotine, and phenols, so it plays an important role in soil ecosystems.

Propionic acid bacteria, or Propionibacterium, were first found in Swiss cheese. They carry out fermentation that produces carbon dioxide, which forms the holes, and propionic acid, which adds flavor. These gram-positive anaerobes can ferment lactic acid, carbohydrates, and polyhydroxy alcohols to make propionic acid, acetic acid, and CO2. During Swiss cheese making, they take part in secondary fermentation by using lactate made by Streptococcus and Lactobacillus as the curd forms. As the curd drains, the bacteria multiply and release CO2. The gas builds up at weak points and creates the cheese holes. Propionigenium is a different bacterium that also produces propionate, but it does so through succinate fermentation.

Mycobacteria are common soil bacteria, and most are harmless. Some species, however, are major human pathogens, including Mycobacterium tuberculosis, which causes tuberculosis. These rod-shaped bacteria are acid-fast because their cell walls contain mycolic acids, which are complex lipids that make the surface waxy and water repellent. They do not stain well with the Gram stain and instead are identified with the Ziehl-Neelsen acid-fast stain, where they keep the red dye while non-acid-fast cells stain blue.

Mycobacteria may look pleomorphic and can sometimes form branching shapes, but they do not make true mycelia like actinomycetes. They include slow-growing species such as M. tuberculosis, M. avium, and M. bovis, and fast-growing species such as M. smegmatis and M. chelonae. Slow growers need longer incubation and form tight, wrinkled, hydrophobic colonies because of their high lipid content. They grow aerobically in simple mineral salts media and can use ammonium as a nitrogen source and glycerol or acetate as a carbon source. M. tuberculosis grows better when lipids and fatty acids are present. Its virulence is linked to cord-like cell groups formed by cord factor, a glycolipid.

Some mycobacteria also make carotenoid pigments that help with identification. They may be nonpigmented, photochromogenic and pigment only in light, or scotochromogenic and pigment even in the dark. These carotenoids likely protect the cells from oxidative damage caused by singlet oxygen.

Actinomycetes are filamentous, aerobic, gram-positive bacteria that are commonly found in soil. Many form desiccation-resistant spores during their developmental cycle. Their growth starts with filament elongation and branching, which creates a mycelium that looks like fungal growth. When nutrients are low, aerial hyphae develop and form spores for survival and spread.

Streptomyces is the most important actinomycete genus and includes more than 500 species. Its filaments are usually 0.5 to 1.0 micrometers wide, grow at the tips, and branch often to form a dense mycelium. As colonies mature, aerial filaments called sporophores appear and make spores called conidia. Unlike Bacillus and Clostridium endospores, conidia form by cross-wall division in the sporophores. Species are classified by differences in aerial filaments and spore structures. Mature Streptomyces colonies are compact, pigmented, and dusty, which makes them easy to spot on agar plates.

Actinobacteria: Soil Bacteria and Cheese

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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

Stramenopile Algae: Diatoms, Golden, Brown

Stramenopile algae include diatoms, golden algae, and brown algae. These phototrophic microorganisms have flagella with many short, hairlike extensions. That feature gave the group its name, which comes from Latin words meaning “straw” and “hair.” Diatoms are unicellular, photosynthetic eukaryotes, and more than 200 genera are known. They are important parts of plankton in both marine and freshwater ecosystems. Their most distinctive feature is a silica-based cell wall called a frustule. This...

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

Learn how Actinobacteria include soil microbes, acid-fast mycobacteria, and Streptomyces, plus the bacteria that create Swiss cheese holes.

Actinobacteria: Soil Bacteria and Cheese | 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

Actinobacteria: Soil Bacteria and Cheese

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