Manor groups of bacteria

1. MAJOR GROUPS OF
BACTERIA
SUBMITTED TO: DR. AKHIL SOORYA SUBMITTED BY: AISWARYA S NAIR
DEPARTMENT OF BOTANY 1st YEAR M.SC BOTANY

2. SPIROCHETES
1. Spirochete, [Order : Spirochaetales]
(spirochaete) is any of a group of spiral
shaped bacteria.
2. Belong to a phylum of distinctive
diderm (double membrane) bacteria.
4.Most of them have long,
helically coiled (corkscrew-
shaped) cells.
3.Chemoheterotrophic
in nature.
5.Characteristically found in liquid
environment.( Eg: Mud and
Water, Blood and Lymph).

3. • They are gram-negative, motile, spiral bacteria, 10 to 30 µm long
and diameters around 0.1–0.6 µm.
• They are unique in having endo cellular flagella called axial
fibrils/axial filaments, which run lengthwise between the bacterial
inner membrane and outer membrane in periplasmic space.
• They number between 2 & more than100 per organism, depending
upon the species.

4. • Each axial fibril attaches at an opposite end and winds around the
cell body, which is enclosed by an envelope.

5. • Reproduce by undergoing asexual transverse binary fission.
• They are micro-aerophilic or anaerobic and are extremely sensitive to
oxygen toxicity.
• Some of them are serious pathogens for humans, causing diseases such
as syphilis, yaws, lyme diseases & relapsing fever.
• The order of spirochaetales is divided into two families:
• 1. Spirochaetaceae
• 2. Leptospiraceae

6. • Examples of genera of spirochetes include Spirochaeta, Treponema, Borrelia,
and Leptospira.
• Treponema includes the agents of syphilis (T. Pallidum pallidum) and yaws (T.
Pallidum pertenue).
• Borrelia includes several species transmitted by lice & ticks and causing
relapsing fever (B. Recurrentis and others) and lyme disease (B. Burgdorferi) in
humans.
• Spirochaeta are free-living non pathogenic inhabitants of mud and water,
typically thriving in anaerobic (oxygen-deprived) environments.
• Leptospirosis, caused by Leptospira, is principally a disease of domestic and
wild mammals and is a secondary infection of humans.

7. RICKETTSIA
• Rickettsia is a genus of non motile, gram-negative, non
spore forming, highly pleomorphic bacteria.
• Occur in the forms of cocci (0.1 μm in diameter), bacilli
(1–4 μm long), or threads (up to about 10 μm long).
• The term "rickettsia" has nothing to do with
Rickets (which is a deficiency disease resulting from
lack of vitamin D);
. The bacterial genus rickettsia instead was named after Howard Taylor Ricketts,
in honor of his pioneering work on tick-borne spotted fever.

8. • Being obligate intracellular bacteria, rickettsias depend on entry, growth,
and replication within the cytoplasm of living eukaryotic host cells
(typically endothelial cells).
• Rickettsia species cannot grow in artificial nutrient culture; they must be
grown either in tissue or embryo cultures; typically, chicken embryos are
used.
• They include the genera rickettsiae, ehrlichia, orientia, and coxiella.
• These zoonotic pathogens cause infections that disseminate in the blood
to many organs.

9. • Many new strains or species of rickettsia are described each year.
• Some are pathogens of medical and veterinary interest, but many are non-pathogenic
to vertebrates, including humans, and infect only arthropods, often non-
hematophagous, such as aphids or whiteflies. Many species are thus arthropod-
specific symbionts.
• Pathogenic rickettsia species are transmitted by numerous types of arthropods,
including chiggers, ticks, fleas, mites, mammals & lice.
• They are associated with both human and plant diseases.
• Rickettsia species are the pathogens responsible for typhus, rickettsialpox
boutonneuse fever, African tick bite fever, rocky mountain spotted fever, flinders
island spotted fever.

10. • The classification of rickettsia into three groups spotted fever, typhus, and
scrub typhus was initially based on serology. This grouping has since been
confirmed by DNA sequencing.
• All three of these groups include human pathogens.
• Rickettsias are more widespread than previously believed and are known
to be associated with arthropods, leeches, & protists.
• Arthropod-inhabiting rickettsiae are generally associated with reproductive
manipulation (such as parthenogenesis) to persist in host lineage.

11. CHLAMYDIA
• Chlamydia are obligatory intacellular bacteria and together
with Rickettsia occupy a unique niche in the microbiology
world.
• For a long time, chlamydia were classified as viruses
because of their dependence on the host cell.
• Since the chlamydia contain RNA, DNA & ribosomes, a
double cell wall, and are suscepctible to antibiotics, they
were later classified as bacteria.
• At present, the genus chlamydia comprises three species.
These are Chlamydia trachomatis, Chlamydia pneumoniae
and Chlaymidia psittaci.

12. MYCOPLASMAS
The mycoplasmas are essentially bacteria
lacking a rigid cell wall during their entire life
cycle, although they are also much smaller than
bacteria. The first organism of this type was
associated with pleuropneumonia of cattle, and
was originally called the pleuropneumonia like
organism (PPLO).
SYSTEMIC POSITION
•DOMAIN: BACTERIA
•PHYLUM: TENERICUTES
•CLASS: MOLLICUTES
•ORDER: MYCOPLASMATALES
•FAMILY: MYCOPLASMATACEAE
•GENUS: MYCOPLASMA

13. CHEMICAL
COMPOSITION:
Protein 40-60%
Carbohydrate 0.1% DNA
Content 3-7% Lipid 8-20
STRUCTURE OF MYCOPLASMA

14. Nocard and Roux contributed for mycoplasma discovery.
• In 1896 Nocard and Roux reported that cultivation of the causative agent of
Contagious Bovine Pleuro Pneumonia {CBPP}, which was at that time a grave
and widespread disease in cattle herds. The work of Nocard and Roux
represented the first isolation of a mycoplasma species.
• The name mycoplasma from the Greek mykes (fungus) and plasma
(formed),was proposed in the 1950s, replacing the term Pleuro Pneumonia-Like
Organisms (PPLO).

15. • Prokaryotic, without rigid cell wall.
• Have no flagella, produce no spores & are gram negative.
• Mycoplasma species are among the smallest organisms yet discovered.
• Bounded by triple-layered membrane.
• Peptidoglycan is absent. This makes them naturally resistant to antibiotics that target
cell wall synthesis.
• They can be parasitic or saprotrophic.
• They can survive without oxygen.
• Several species are pathogenic in humans, including M. pneumoniae, which is an
important cause of walking pneumonia and other respiratory disorders. M.genitalium,
which is believed to be involved pelvic inflammatory diseases.

16. • Their cells can be conformed to different shape. Eg: M. genitalium - Flask shaped,
M.pneumoniae – More elongated. Many other species are coccoid.
• These shapes contribute to the ability of mycoplasmas to thrive in respective
environments.
• Eg: M. pneumoniae; cells possess an extended ‘arm’ protruding from a coccoid cell
body, which is involved in the attachment of this pathogenic bacterium to the tissue of
human host, in movement along solid surfaces, and in cell division.
• Mycoplasma species are often found in research laboratories as contaminants in cell
culture. Mycoplasma cells are physically small (<1µm), so are difficult to detect with a
conventional microscope.
• Detection techniques include DNA probe/enzyme immuno assay/PCR/sensitive agar &
staining with DNA stain.

17. • They are normally destroyed by heat at 45°c in 15 minutes.
• They are relatively resistant to Pencillins, and Cephalosporins.
• Sensitive to tetracyclines, and several other antibiotics.
• They usually reproduce by binary fission budding or round
body formation and filamentous formation.
• Scientists have isolated at least 17 species of mycoplasma from
humans, 4 types of organisms are responsible for most
clinically significant infections. These species are Mycoplasma
pneumoniae, Mycoplasma hominis, Mycoplasma genitalium,
and Ureaplasma species.

18. MYCOPLASMA PNEUMONIAE
UREAPLASMA SPECIES

19. MYCOPLASMA HOMINIS
MYCOPLASMA GENITALIUM

20. NANOBES
A nanobe is a tiny filamental structure, first
found in some rocks and sediments.
Some scientists hypothesise that nanobes
are the smallest form of life.
Has 1/10th size of the smallest known
bacteria.

21. • A new controversy discovery by scientists as tiny cells that look like
dwarf bacteria but are ten times smaller than mycoplasma and
hundred times smaller than the average bacterial cell.
• Nanobacteria like forms were first isolated from blood & serum
samples.
• Nanobacteria are thought to have been found in human blood and may
be related to health issues such as formation of kidney stones due to
their biomineralization processes.

22. VBNCS
• Viable but non-culturable cells (VBNC) are defined as live bacteria, but
which do not either grow or divide.
• They cannot be cultivated on conventional media.
• They do not form colonies on solid media and do not change broth
appearance.
• Many bacterial species have been found to
exist in a viable but non-culturable (VBNC) state
since its discovery in 1982.

23. • It was first discovered in 1982 that Escherichia coli and Vibrio cholerae cells
could enter a distinct state called the viable but non-culturable (VBNC) state.
• Unlike normal cells that are culturable on suitable media and develop into
colonies, VBNC cells are living cells that have lost the ability to grow on routine
agar media, on which they normally grow which impairs their detection by
conventional plate count techniques.
• This leads to an underestimation of total viable cells in environmental or
clinical samples, and thus poses a risk to public health.

24. • Despite their non-culturability on normally permissive media, VBNC cells are not regarded
as dead cells.
• Because VBNC cells have an intact membrane containing undamaged genetic information.
The plasmids, if any, are also retained in VBNC cells.
• While dead cells are metabolically inactive, VBNC cells are metabolically active and carry
out respiration.
• High ATP level was found in Listeria monocytogenes even one year after entering the
VBNC state. Moreover, dead cells do not express genes, while VBNC cells continue
transcription and therefore, mRNA production.
• In contrast to dead cells that no longer utilize nutrients, VBNC cells were shown to have
continued uptake and incorporation of amino acids into proteins.

25. • Viable but non-culturable stage is reversible. Both gram positive and gram
negative bacteria can enter the VBNC stage.
• Many studies show that processes meant to achieve bactericidal effects
can favour bacterial switch to VBNC.
• The switch to this stage shown by several bacteria species; Vibrio species
(cholerae, vulnificus, Escherichia coli), Salmonella spp. , Pseudomonas
spp. (Mycobacterium tuberculosis), Enterococcus spp. etc.

26. MYXOBACTERIA
Myxobacteria are Gram-negative single-celled,
eubacterial predators. They represent one of
nature's explorations of communal living, in as
much as they move and feed in groups.
Myxobacteria also construct species-specific
multicellular structures called fruiting bodies
and differentiate spores within them.

27. • Myxobacteria "slime bacteria“ are a group of bacteria that predominantly live in the soil
and feed on insoluble organic substances.
• Have very large genomes relative to other bacteria
• One species of myxobacteria, Minicystis rosea, has the largest known bacterial genome
with over 16 million nucleotides.
• The second largest is another myxobacteria Sorangium cellulosum.
• Move by gliding. They typically travel in swarms (also known as wolf packs), containing
many cells kept together by intercellular molecular signals.
• Myxobacteria are used to study the polysaccharide production in gram-negative bacteria
like the model Myxococcus xanthus .

28. Myxococcus xanthus
• Myxobacteria are also good models to study the multicellularity in the
bacterial world.

29. • (A) Myxococcus xanthus - fruiting bodies emerging from a soil particle.
• (B) sketch of a Chondromyces crocatus fruiting body.
• (C) spherical spore and vegetative rod forms of M. xanthus cells.
Myxobacterial social phenotypes.

30. • (D ) Sketch of a Chondromyces aurantiacus - fruiting body.
• (E) M. Xanthus - fruiting body.
• (F) Sketch of a Myxococcus coralloides fruiting body.
• (G) M. Xanthus cells engaging in coordinated motility.
• (H) Sketch of swarming and individual cells of C.
aurantiacus.
• (I)M. Xanthus swarm (movement left to right) consuming
a colony of Escherichia coli.

31. NATURAL PRODUCTS FROM MYXOBACTERIA: NOVEL
METABOLITES AND BIOACTIVITIES
• Myxobacteria produce a number of biomedically
and industrially useful chemicals, such as
antibiotics, and export those chemicals outside the
cell.
• Myxobacteria are a rich source for structurally
diverse secondary metabolites with intriguing
biological activities.
• New natural products were isolated from
myxobacteria in the period of 2011 to 2016.

32. ARCHAEBACTERIA
Archaebacteria are known to be the oldest
living organisms on earth. They belong to
the kingdom Monera and are classified as
bacteria because they resemble bacteria
when observed under a microscope. Apart
from this, they are completely distinct from
prokaryotes. However, they share slightly
common characteristics with the
eukaryotes.

33. • Archaebacteria are obligate or facultative anaerobes, ie, They flourish in the
absence Of oxygen and that is why only they can undergo methanogenesis.
• The cell membranes of the archaebacteria are composed of lipids.
• The rigid cell wall provides shape and support to the archaebacteria. It also
protects the cell from bursting under hypotonic conditions.
• The cell wall is composed of pseudomurein, which prevents archaebacteria from
the effects of lysozyme.
• Lysozyme is an enzyme released by the immune system of the host, which
dissolves the cell wall of pathogenic bacteria.

34. • They do not possess membrane-bound organelles such as nuclei, endoplasmic
reticulum, mitochondria, lysosomes or chloroplast.
• Its thick cytoplasm contains all the compounds required for nutrition and
metabolism.
• They can live in a variety of environments and are hence called extremophiles.
• They can survive in acidic and alkaline aquatic regions, and also in temperature
above Boiling point.
• They can withstand a very high pressure of more than 200 atmospheres.
• Archaebacteria are indifferent towards major antibiotics because they contain
Plasmids which have antibiotic resistance enzymes.

35. • The mode of reproduction is asexual, known as binary fission.
• They perform unique gene transcription.
• The differences in their ribosomal RNA suggest that they diverged from both
prokaryotes and eukaryotes.
• Types of Archaebacteria :
• There are the 3 types of archaebacteria. Archaea that live in salty environments are
known as halophiles. Archaea that live in extremely hot environments are called
thermoacidophiles. Archaea that produce methane are called methanogens.
• Archaebacteria are classified on the basis of their phylogenetic relationship.
• The major types of archaebacteria are : Crenarchaeota, Euryarchaeota,
Korarchaeota, Thaumarchaeota & Nanoarchaeota.

36. EXAMPLES OF ARCHAEBACTERIA:
• LOKIARCHEOTA
• It is a thermophilic archaebacterium found in deep-sea
vents known as the Loki’s castle.
• It has a unique genome.
• Some of the genes of the genome are involved in
phagocytosis.
• They also possess the eukaryotic genes that are used by
the eukaryotes to control their shapes.
• It is believed that Lokiarcheota and eukaryotes shared a
common ancestor several billion years ago.

37. METHANOBREVIBACTER SMITHII
• It is a methane-producing bacteria
found in the human gut.
• It helps in the breakdown of complex
plant sugars and extracts energy from
the food consumed by us.
• Some help to protect against colon
cancer. People suffering from colon
cancer and obesity have very high levels
of euryarchaeota bacteria in their gut.

38. ACTINOMYCETES
Actinomycetes are a group of unicellular
filamentous bacteria that form a branching
network of filaments and produce spores.
They have long been recognized as sources of
severe earthy-musty tastes and odours in
drinking water.
Gram stain: Gram positive
Morphology: Filamentous lengths of cocci
Respiration: Mostly aerobic, can be anaerobic
Habitat: Soil or marine.

39. • Actinomycetes are a broad group of bacteria that form
thread-like filaments in the soil.
• The distinctive scent of freshly exposed, moist soil is
attributed to these organisms, especially to the nutrients
they release as a result of their metabolic processes.
• Actinomycetes form associations with some non-
leguminous plants and fix N, which is then available to
both the host and other plants in the near vicinity.

40. • The actinomycetota (or actinobacteria) are a phylum of mostly gram positive
bacteria .
• They can be terrestrial or aquatic.
• They are of great economic importance to humans because agriculture and forests
depend on their contributions to soil systems.
• In soil they help to decompose the organic matter of dead organisms so the
molecules can be taken up anew by plants.
• Actinomycetota is one of the dominant bacterial phyla under actinomycetes and
contains one of the largest of bacterial genera, streptomyces.
• Streptomyces and other actinomycetota are major contributors to
biological buffering of soils. They are also the source of many antibiotics.

41. • Actinomycetota, especially streptomyces spp., are recognized as the producers
of many bioactive metabolites that are useful to humans in:
• Medicine such as antibacterials, antifungals, antivirals, antithrombotics,
immunomodifiers, antitumor drugs,
• Enzyme inhibitors, in agriculture, including insecticides, herbicides, fungicides,
& growth-promoting substances for plants and animals.
• Actinomycetota-derived antibiotics that are important in medicine include
aminoglycosides, anthracyclines, chloramphenicol, macrolide, tetracyclines etc.
• Actinomycetota have high guanine and cytosine content in their DNA.

42. Actinomycetes are soil microorganisms like both bacteria and fungi, & have
characteristics linking them to both groups.
They have many processes that are beneficial to soil health including:
• Decomposition of cellulose matter
• Ammonium fixation and synthesis
• Degradation of humus
• Disease resistance
• Act as biocontrol agents
• Bioremediation of lignin, cellulose, petroleum, and heavy metal contaminants

43. • They play major roles in the cycling of organic matter; inhibit the growth of
several plant pathogens in the rhizosphere and decompose complex mixtures of
polymer in dead plant, animal and fungal material results in production of many
extracellular enzymes which are conductive to crop production.
• The major contribution in biological buffering of soils, biological control of soil
environments by nitrogen fixation and degradation of high molecular weight
compounds like hydrocarbons in the polluted soils are remarkable characteristics
of actinomycetes.
• Besides this, they are known to improve the availability of nutrients, minerals,
enhance the production of metabolites and promote plant growth regulators.

44. SUBMITTEDBY : AISWARYAS NAIR
1ST MSCBOTANY
THANK
YOU