Bacillus

Bacillus, from Latin "bacillus", meaning "little staff, wand", is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum Bacillota, with 266 named species. These tiny living things are found everywhere in nature. Some can live only where there is oxygen, while others can survive without it.

One amazing ability of Bacillus is to shrink down into tiny protective balls called oval endospores. These endospores can stay safe for many years, even after being heated very hot or treated with strong cleaning agents. This makes them tricky to get rid of in places like hospitals or food factories.

Two types of Bacillus are important for humans. B. anthracis can cause a serious illness called anthrax, while B. cereus can make food go bad and cause food poisoning. But many Bacillus species are helpful. They make useful substances like enzymes that break down starch and help clean things. One species, B. subtilis, is often used by scientists to study how bacteria live and grow. Some Bacillus even help protect fish like Labeo rohita_ by making natural medicines.

Structure

The cell wall of Bacillus is a layer outside the cell that helps keep its rod shape and protects it from the outside world. It is made from special kinds of acids and helps the cell stay strong.

Bacillus species are rod-shaped bacteria that can live with or without oxygen. They can form a tough protective spore that helps them survive extreme conditions like heat, cold, and radiation. Each cell can make only one of these spores.

Origin of name

The group of bacteria called Bacillus was named in 1835 by a scientist named Christian Gottfried Ehrenberg. He used the name to describe bacteria that have a rod shape, like tiny little staffs. Later, another scientist named Ferdinand Cohn added that these bacteria can form special protective spores, and they are a type that needs oxygen or can live without it. There are 266 different kinds of Bacillus bacteria, and they can be found almost everywhere. Like other early discovered bacteria groups such as Pseudomonas and Vibrio, Bacillus has a lot of variety in its ribosomal 16S makeup.

Isolation and identification

Scientists can find Bacillus bacteria by taking a sample of soil and mixing it with clean water. They then heat the mixture to remove other cells, leaving mainly tiny, tough parts called spores. These spores are placed on special plates where they grow into colonies.

When looked at under a microscope, Bacillus cells look like small rods, and many have oval endospores at one end, which makes them look puffy.

Characteristics of Bacillus spp.

Scientists in 2021 found many types of Bacillus subtilis from sea sponges near Saint Martin's Island in the Bay of Bengal, Bangladesh. They studied these bacteria and shared what they look like and how they act.

Phylogeny

Scientists have studied the family tree of bacteria called Bacillus for a long time. They found that the old way of grouping these bacteria was too loose.

Researchers have used different methods, like looking at parts of the bacteria’s DNA, to sort them into groups. Some studies split Bacillus into many smaller groups, creating new names for some of these groups. This helps us understand how these bacteria are related to each other.

One group of Bacillus bacteria includes several species that are very similar to each other. Even though they are often treated as separate species for medical reasons, they could actually be one species.

Species

Some types of bacteria that used to be called Bacillus have been moved to other groups. These include:

• B. Symun
• B. acidicola
• B. acidiproducens
• B. acidocaldarius
• B. acidoterrestris
• B. aeolius
• B. agaradhaerens
• B. agri
• B. aidingensis
• B. akibai
• B. albus
• B. alcalophlus
• B. algicola
• B. alginolyticus
• B. alkalidiazotrophicus
• B. alkalinitrilicus
• B. alkalisediminis
• B. alkalitelluris
• B. alveayuensis
• B. alvei
• B. aminovorans
• B. amylolyticus
• B. andreesenii
• B. aneurinilyticus
• B. anthracis
• B. aquimaris
• B. arenosi
• B. arseniciselenatis
• B. arsenicus
• B. aurantiacus
• B. arvi
• B. aryabhattai
• B. asahii
• B. axarquiensis
• B. azotofixans
• B. azotoformans
• B. badius
• B. barbaricus
• B. bataviensis
• B. beijingensis
• B. benzoevorans
• B. beringensis
• B. berkeleyi
• B. beveridgei
• B. bogoriensis
• B. boroniphilus
• B. borstelensis
• B. brevis
• B. butanolivorans
• B. canaveralius
• B. carboniphilus
• B. cecembensis
• B. cellulosilyticus
• B. centrosporus
• B. cereus
• B. chagannorensis
• B. chitinolyticus
• B. chondroitinus
• B. choshinensis
• B. chungangensis
• B. cibi
• B. circulans
• B. clarkii
• B. clausii
• B. coagulans
• B. coahuilensis
• B. cohnii
• B. composti
• B. curdlanolyticus
• B. cycloheptanicus
• B. cytotoxicus
• B. daliensis
• B. decisifrondis
• B. decolorationis
• B. deserti
• B. dipsosauri
• B. drentensis
• B. edaphicus
• B. ehimensis
• B. eiseniae
• B. enclensis
• B. endophyticus
• B. endoradicis
• B. farraginis
• B. fastidiosus
• B. fengqiuensis
• B. filobacterium rodentuim
• B. firmus
• B. flexus
• B. foraminis
• B. fordii
• B. formosus
• B. fortis
• B. fumarioli
• B. funiculus
• B. fusiformis
• B. gaemokensis
• B. galactophilus
• B. galactosidilyticus
• B. galliciensis
• B. gelatini
• B. gibsonii
• B. ginsengi
• B. ginsengihumi
• B. ginsengisoli
• B. glucanolyticus
• B. gordonae
• B. gottheilii
• B. graminis
• B. halmapalus
• B. haloalkaliphilus
• B. halochares
• B. halodenitrificans
• B. halodurans
• B. halophilus
• B. halosaccharovorans
• B. hemicellulosilyticus
• B. hemicentroti
• B. herbersteinensis
• B. horikoshii
• B. horneckiae
• B. horti
• B. huizhouensis
• B. humi
• B. hwajinpoensis
• B. idriensis
• B. indicus
• B. infantis
• B. infernus
• B. insolitus
• B. invictae
• B. iranensis
• B. isabeliae
• B. isronensis
• B. jeotgali
• B. kaustophilus
• B. kobensis
• B. kochii
• B. kokeshiiformis
• B. koreensis
• B. korlensis
• B. kribbensis
• B. krulwichiae
• B. laevolacticus
• B. larvae
• B. laterosporus
• B. lautus
• B. lehensis
• B. lentus
• B. ligniniphilus
• B. litoralis
• B. locisalis
• B. luciferensis
• B. luteolus
• B. luteus
• B. macauensis
• B. macerans
• B. macquariensis
• B. macyae
• B. malacitensis
• B. mannanilyticus
• B. marisflavi
• B. marismortui
• B. marmarensis
• B. massiliensis
• B. megaterium
• "B. mesentericus_"
• B. mesonae
• B. methanolicus
• B. methylotrophicus
• B. migulanus
• B. mucilaginosus
• B. muralis
• B. murimartini
• B. mycoides
• B. naganoensis
• B. nanhaiensis
• B. nanhaiisediminis
• B. nealsonii
• B. neidei
• B. neizhouensis
• B. niabensis
• B. niacini
• B. novalis
• B. oceanisediminis
• B. odysseyi
• B. okhensis
• B. okuhidensis
• B. oleronius
• B. oryzaecorticis
• B. oshimensis
• B. pabuli
• B. pakistanensis
• B. pallidus
• B. pallidus
• B. panacisoli
• B. panaciterrae
• B. pantothenticus
• B. parabrevis
• B. paraflexus
• B. pasteurii
• B. patagoniensis
• B. peoriae
• B. persepolensis
• B. persicus
• B. pervagus
• B. plakortidis
• B. pocheonensis
• B. polygoni
• B. polymyxa
• B. popilliae
• B. pseudalcalophilus
• B. pseudofirmus
• B. pseudomycoides
• B. psychrodurans
• B. psychrophilus
• B. psychrosaccharolyticus
• B. psychrotolerans
• B. pulvifaciens
• B. purgationiresistens
• B. pycnus
• B. qingdaonensis
• B. qingshengii
• B. reuszeri
• B. rhizosphaerae
• B. rigui
• B. ruris
• B. salarius
• B. salexigens
• B. saliphilus
• B. schlegelii
• B. sediminis
• B. selenitarsenatis
• B. selenitireducens
• B. seohaeanensis
• B. shacheensis
• B. shackletonii
• B. silvestris
• B. simplex
• B. siralis
• B. smithii
• B. soli
• B. solimangrovi
• B. solisalsi
• B. songklensis
• B. sphaericus
• B. sporothermodurans
• B. stearothermophilus
• B. stratosphericus
• B. subterraneus
• B. taeanensis
• B. thermantarcticus
• B. thermoaerophilus
• B. thermoamylovorans
• B. thermocatenulatus
• B. thermocloacae
• B. thermocopriae
• B. thermodenitrificans
• B. thermoglucosidasius
• B. thermolactis
• B. thermoleovorans
• B. thermophilus
• B. thermoproteolyticus
• B. thermoruber
• B. thermosphaericus
• B. thiaminolyticus
• B. thioparans
• B. thuringiensis
• B. tianshenii
• B. toyonensis
• B. trypoxylicola
• B. tusciae
• B. validus
• B. vedderi
• B. vietnamensis
• B. vireti
• B. vulcani
• B. wakoensis
• B. xiaoxiensis
• B. zanthoxyli
• B. zhanjiangensis

Ecological and clinical significance

Bacillus species are found everywhere in nature, especially in soil. They can live in very tough places, like areas with very high or low pH, very hot temperatures, or lots of salt. These bacteria also live inside plants and help them stay healthy by supporting their immune systems, helping them absorb nutrients, and fixing nitrogen.

Some Bacillus species are useful for humans. For example, B. thuringiensis makes a natural toxin that can kill insects, so it is used as a safe insecticide. Another species, B. siamensis, can fight harmful fungi and help plants grow.

Two Bacillus species can make people sick. B. anthracis causes a disease called anthrax, and B. cereus can cause food poisoning, leading to stomach problems like vomiting or diarrhea. B. subtilis is often studied by scientists and can sometimes spoil food, making bread taste bad. Some types of B. coagulans might also spoil acidic foods like tomato products.

Industrial significance

Many types of Bacillus bacteria can produce large amounts of helpful substances. For example, Bacillus amyloliquefaciens creates a natural antibiotic and enzymes used in cleaning products and DNA research.

Some Bacillus bacteria have been used to help crops like corn and cotton stay safe from certain pests. Bacillus subtilis is important in making a traditional food called natto.

Bacillus bacteria are very useful in factories because they can make many important substances, such as vitamins and flavorings. Scientists are always finding new ways to use these bacteria to create helpful products.

Use as model organism

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Bacillus subtilis is one of the best-studied simple living things. Scientists use it to learn about how tiny life forms work. Because it is easy to study and big enough to see clearly, it helps researchers explore many parts of bacterial life. New ways to see cells with light have helped scientists learn even more about how a single cell lives and changes. Studies of B. subtilis have led to big discoveries in how bacteria grow, control their genes, and go through their life cycles.