9. Scientific Names
Scientific Binomial Source of Genus Name Source of
Specific Epithet
Klebsiella pneumoniae Honors Edwin Klebs The disease
Pfiesteria piscicida Honors Lois Pfiester Disease in fish
Salmonella typhimurium Honors Daniel Salmon Stupor (typh-) in mice
(muri-)
Streptococcus pyogenes Chains of cells (strepto-) Forms pus (pyo-)
Penicillium chrysogenum Tuftlike (penicill-) Produces a yellow (chryso-)
pigment
Trypanosoma cruzi Corkscrew-like (trypano-, Honors Oswaldo Cruz
borer; soma-, body)
Parungao-Balolong 2011
Tuesday, June 21, 2011
11. DEFINING “SPECIES”
• Eukaryotic species: A group of closely related
organisms that breed among themselves
• Prokaryotic species: A population of cells with
similar characteristics
• Clone: Population of cells derived from a single
cell
• Strain: Genetically different cells within a clone
• Viral species: Population of viruses with similar
characteristics that occupies a particular
ecological niche
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Tuesday, June 21, 2011
12. DOMAIN EUKARYA
•Animalia: Multicellular; no cell walls;
chemoheterotrophic
•Plantae: Multicellular; cellulose cell walls;
usually photoautotrophic
•Fungi: Chemoheterotrophic; unicellular or
multicellular; cell walls of chitin; develop
from spores or hyphal fragments
•Protista: A catchall for eukaryotic
organisms that do not fit other kingdoms
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14. NAMING YOUR UNKNOWN
MICROBE
Bergey’s Manual of Determinative Morphology, differential staining,
Bacteriology biochemical tests
Provides identification schemes for
identifying bacteria and archaea
Bergey’s Manual of Systematic Based on rRNA sequencing
Bacteriology
Provides phylogenetic information on
bacteria and archaea
Approved Lists of Bacterial Names Based on published articles
Lists species of known prokaryotes
Parungao-Balolong 2011
Tuesday, June 21, 2011
15. IDENTIFYING YOUR UNKNOWN
MICROBE
• Morphological
characteristics: Useful
for identifying
eukaryotes
• Differential staining:
Gram staining, acid-
fast staining
• Biochemical tests:
Determines presence
of bacterial enzymes
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Tuesday, June 21, 2011
21. CLADOGRAMS
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22. Lecture Outline
•Classifications of
Microorganisms
•Prokaryotes
•Eukaryotes
•Viruses, Viroids,
Prions
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23. THE
PROKARYOTES
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24. PROTEOBACTERIA
• includes most of the Gram negative,
chemoheterotrophic bacteria
• presumes to have risen from a common
photosynthetic ancestor
• largest taxonomic group of bacteria
• 5 classes: alphaproteobacteria,
betaproteobacteria, gammaproteobacteria,
deltaproteobacteria, epsilonproteobacteria
Parungao-Balolong 2011
Tuesday, June 21, 2011
29. IMPORTANT GENERA
& Features
Sphaerotilus Spirillum Fimbriae and
(forms sheaths) (forms sheaths)
Capsules =
Pathogenicity
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Tuesday, June 21, 2011
67. Lecture Outline
•Classifications of
Microorganisms
•Prokaryotes
•Eukaryotes
•Viruses, Viroids,
Prions
Parungao-Balolong 2011
Tuesday, June 21, 2011
68. VIRUSES
• Contain DNA or RNA
• Contain a protein coat
• Some are enclosed by an
envelope
• Some viruses have spikes
• Most viruses infect only
specific types of cells
in one host
• Host range is determined by
specific host attachment sites
and cellular factors
Parungao-Balolong 2011
Tuesday, June 21, 2011
70. HOW ARE THEY NAMED?
• Family names end in -viridae. EXAMPLE
Herpesviridae
• Genus names end in -virus Herpesvirus
• Viral species: A group of Human herpes virus
viruses sharing the same
genetic information and EXAMPLE
ecological niche (host)
Retroviridae
• Common names are used Lentivirus
for species Human
immunodeficiency virus
• Subspecies are designated HIV-1, HIV-2
by a number
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72. LIFE CYCLE
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73. LIFE CYCLE
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74. LIFE CYCLE
Lytic cycle: Phage causes lysis and death of host
cell.
Lysogenic cycle: Prophage DNA incorporated in host
Parungao-Balolong 2011
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75. LIFE CYCLE
Lytic cycle: Phage causes lysis and death of host cell.
Lysogenic cycle: Prophage DNA incorporated in
host DNA.
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Tuesday, June 21, 2011
79. VIRUS MULTIPLICATION
(+ strand RNA Virus)
Attachment
Capsid
Nucleus
RNA
Cytoplasm
Host cell
Entry
Maturation and uncoating
and release
Translation and synthesis RNA replication by viral RNA-
of viral proteins dependent RNA polymerase
Uncoating releases
– strand is transcribed viral RNA and proteins.
from + viral genome.
Capsid Viral Viral
protein genome protein
(RNA)
(a) ssRNA; +
+ strand or sense strand;
Picornaviridae
mRNA is transcribed
from the – strand.
Parungao-Balolong 2011
Tuesday, June 21, 2011
80. VIRUS MULTIPLICATION
(- strand RNA Virus)
Attachment
Capsid Nucleus
RNA Cytoplasm
Host cell
Entry
Maturation and uncoating
and release
Translation and synthesis RNA replication by viral RNA-
of viral proteins dependent RNA polymerase
Uncoating releases
viral RNA and proteins.
The + strand (mRNA) must first
be transcribed from the – viral
Viral Viral
genome before proteins can
genome protein
be synthesized.
(RNA)
Capsid
protein
(b) ssRNA; – or
– strands are antisense strand;
incorporated Rhabdoviridae
into capsid Additional – strands are
transcribed from mRNA.
Parungao-Balolong 2011
Tuesday, June 21, 2011
81. VIRUS MULTIPLICATION
(dsRNA Virus)
Attachment
Capsid Nucleus
RNA
Cytoplasm
Host cell
Entry
Maturation and uncoating
and release
Translation and synthesis RNA replication by viral RNA-
of viral proteins dependent RNA polymerase
Uncoating releases
RNA polymerase initiates production of mRNA is produced inside the viral RNA and proteins.
– strands. The mRNA and – strands form the capsid and released into the
dsRNA that is incorporated as new viral genome. cytoplasm of the host. Viral
Viral
genome protein
(RNA)
(c) dsRNA; + or sense
Capsid proteins and RNA- strand with – or
dependent RNA polymerase antisense strand;
Reoviridae
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84. DNA vs RNA VIRUSES
• DNA: Cellular enzyme • RNA – strand: Viral
transcribes viral DNA in enzyme copies viral RNA
nucleus to make mRNA in
cytoplasm
• DNA, reverse
transcriptase: Cellular • RNA, double-stranded:
enzyme transcribes viral Viral enzyme copies –
DNA in nucleus; reverse strand RNA to make
transcriptase copies mRNA in cytoplasm
mRNA to make viral DNA
• RNA, reverse
• RNA, + strand: Viral RNA transcriptase: Viral
is a template for enzyme copes viral RNA
synthesis of RNA to make DNA in
polymerase. cytoplasm.
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85. VIRUSES & CANCER
• CANCER
• Activated oncogenes transform normal
cells into cancerous cells.
• Transformed cells have increased growth,
loss of contact inhibition, tumor specific
transplant and T antigens.
• The genetic material of oncogenic viruses
becomes integrated into the host cell's
DNA.
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86. VIRUSES & CANCER
• Oncogenic DNA • Oncogenic RNA
viruses viruses
• Adenoviridae • Retroviridae
• Heresviridae • Viral RNA is
transcribed to DNA
• Poxviridae which can integrate
into host DNA
• Papovaviridae
• Hepadnaviridae • HTLV 1
• HTLV 2
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87. • Latent viral infections
• Virus remains in LATENT vs
asymptomatic host cell PERSISTENT VIRAL
for long periods INFECTIONS
• Cold sores, shingles
• Persistent viral
infections
• Disease processes
occurs over a long
period; generally is
fatal
• Subacute sclerosing
panencephalitis
(measles virus) Parungao-Balolong 2011
Tuesday, June 21, 2011
88. PRIONS
• Infectious proteins
• Inherited and transmissible
by ingestion, transplant, and
surgical instruments
• Spongiform
encephalopathies: Sheep
scrapie, Creutzfeldt-Jakob
disease, Gerstmann-
Sträussler-Scheinker
syndrome, fatal familial
insomnia, mad cow disease
• PrPC: Normal cellular prion
protein, on cell surface
• PrPSc: Scrapie protein;
accumulates in brain cells
forming plaques
Parungao-Balolong 2011
Tuesday, June 21, 2011
91. FAMILY OF VIRUSES
ssDNA dsDNA
Human Parvovirus
Human Respiratory
Infections Wart Viruses
Smallpox; Cowpox
Herpes Simplex 1 and 2 Hepatitis B
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Tuesday, June 21, 2011
92. FAMILY OF VIRUSES
ssRNA (-)
Rabies Ebola Mumps Hepatitis D
Influenza
Hantavirus Lassa Fever
ssRNA (+)
Rhinovirus
Hepatitis E
Dengue
Rubella
SARS Parungao-Balolong 2011
Tuesday, June 21, 2011
93. FAMILY OF VIRUSES
ssRNA, 2
strands dsRNA
HIV Rotavirus
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