Gram Negatives Lecture Notes PDF

Gram Negatives PUBLIC / CYHOEDDUS  PUBLIC / Learning Objectives CYHOEDDUS Look at the Linneaus classification system and how it...

Gram Negatives PUBLIC / CYHOEDDUS  PUBLIC / Learning Objectives CYHOEDDUS Look at the Linneaus classification system and how it applies to Prokaryotes Learn how to write Latin organism names Learn some of the major lineages of bacteria Learn to describe the main features of the Pseudomonadota and give some detailed examples Describe the main features of the Gram negative Non- Pseudomonadota and give some detailed examples Taxonomic PUBLIC / CYHOEDDUS Hierarchy  PUBLIC / Writing Latin Names CYHOEDDUS Bacteria are known by their Latin names You’ll see the genus followed by the species Thegenus name starts with an upper-case letter and the species names with a lower-case letter If typing the name, it should be in italics, if handwriting the name, it should be underlined When writing the name for the first time it should be written in full, for any subsequent uses it can be shortened  Escherichia PUBLIC / Perfect Example CYHOEDDUS coli (E. coli)  PUBLIC / Which is Written Correctly? CYHOEDDUS 1. Bacillus subtilis 2. Bacillus Subtilis 3. bacillus subtilis 4. Bacillus subtilis 5. Bacillus Subtilis  PUBLIC / Is this Written Correctly? CYHOEDDUS  PUBLIC / Is this Written Correctly? Helicobacter CYHOEDDUS pylori (H.pylori)  PUBLIC / Is this Written Correctly? CYHOEDDUS Pseudomonas aeruginosa (P. aeruginosa)  PUBLIC / Is this Written Correctly? CYHOEDDUS Burkholderia cepacia (B. cepacia) Classifying Prokaryotes PUBLIC / CYHOEDDUS Domain Bacteria Domain Archaea Gram Negative Gram Positive Pseudomonadota Non-Pseudomonadota  Phylum: Pseudomonadota PUBLIC / CYHOEDDUS (Proteobacteria) Largestand most diverse phylum Domain Bacteria of bacteria Gram Negative Gram Positive Fivedistinct classes – alpha, beta, gamma, delta, epsilon Variety of shapes Pseudomonadota Non-Pseudomonadota All Gram negative Show extreme metabolic diversity Industrial, medical and agricultural significance Enteric Bacteria PUBLIC / CYHOEDDUS Gammaproteobacteria Coccobacilli or bacilli Most common Gram negative pathogens of humans If motile, they have peritrichous flagella Some have capsules All are facultative anaerobes O, H and K antigens Includes opportunistic pathogens like E. coli, and Salmonella species Salmonella PUBLIC / CYHOEDDUS Found in birds, reptiles and mammals Approximately 1/3 of chicken eggs infected Salmonellosis- large infectious dose, non-bloody diarrhoea Recent outbreak in the USA Typhoid fever- lower infectious dose, phagocytosed and carried through body Yersinia pestis PUBLIC / CYHOEDDUS Causes bubonic plague or “black death”, and pneumonic plague True pathogen Killed one third of humans in epidemics in the middle ages Yersinia pestis PUBLIC / CYHOEDDUS Yersinia pestis PUBLIC / CYHOEDDUS Buboes- swollen lymph nodes Entersbloodstream causing septicaemia Necrosis of tissue Virulence plasmids- toxins that can lyse red blood cells Type III secretion system- secretes proteins that aid in infection  PUBLIC / Non-Enteric Pseudomonadota CYHOEDDUS The Vibrio group- Gammaproteobacteria Bdellovibrio -Deltaproteobacteria Caulobacter- Alphaproteobacteria Aliivibrio fischeri (Vibrio fischeri ) PUBLIC / CYHOEDDUS Marine living Facultative anaerobe Bioluminescent- luciferase Symbiotic relationship- light organ, quorum sensing Seekout organisms using chemotaxis  Bdellovibrio PUBLIC / CYHOEDDUS Predatory Attacks a wide range of Gram negative pathogens A living antibiotic? Doesnot attack eukaryotic cells Weakly immunogenic in animals Caulobacter PUBLIC / CYHOEDDUS Alphaproteobacteria Aquatic (freshwater) Model organism for cell division Swarmer cell and stalked cell Prosthecae- attachment Bacterial superglue  PUBLIC / Non-Pseudomonadota CYHOEDDUS Not a taxonomic group itself A way to classify the smaller Gram negative phyla Lotsof interesting and diverse microorganisms with roles in evolution and disease Phylum: Cyanobacteriota PUBLIC / CYHOEDDUS (Cyanobacteria) Largeand morphologically diverse group Coccus or disc shaped 1-10 µm diameter Some are motile by gliding Oxygenic phototrophs Lichens Abundantin aquatic environments Importance of Cyanobacteriota PUBLIC / CYHOEDDUS Today Nitrogenfixation- Azolla, heterocysts Important source of oxygen and sink for carbon dioxide Geosmin- earthy smell when it rains Cyanotoxins e.g. neurotoxins, cytotoxins, endotoxins, hepatotoxins Phylum: Spirochaetota PUBLIC / CYHOEDDUS (Spirochetes) Thin 0.1-0.5 µm Corkscrew rotation Axialfilaments- motility Threepathogenic genera- Treponema, Borrelia and Leptospira Treponema PUBLIC / CYHOEDDUS Anaerobic or microaerophilic Commensals of humans and animals Neverbeen grown in laboratory culture Treponema pallidum causes syphilis  PUBLIC / Syphilis CYHOEDDUS 12 million new cases annually 1 in 10 people exposed to syphilis will get it Spread through sexual contact Primary stage: chancre Secondary stage: fever, rash Tertiary stage: central nervous system Adherence, hyaluronidase and a capsule important to infection Penicillin, doxycycline Historical treatment Phylum: Bacteriodota PUBLIC / CYHOEDDUS (Bacteroidetes) Anaerobic (mostly) Commensal ~1 billion per gram of faeces Moreprevalent in n on-obese people Cancer treatment e ffectiveness Alistipes PUBLIC / CYHOEDDUS Commonly found in the intestinal tract of humans and animals Dysbiosis can be problematic Thought to correlate with positive cancer therapy outcomes (specifically colorectal and lung) More abundant in people with depression Phylum: Chlamydiota PUBLIC / CYHOEDDUS (Chlamydiae) Obligately intracellular Pathogenic in humans and other animals Can be symbiotic Cannot be grown in traditional laboratory media Phylum: Chlamydiota PUBLIC / CYHOEDDUS (Chlamydiae) Very small Genome reduced- 1 Mb, 1000 genes Usually no plasmids Steals from host cell Elementary bodies- infectious, 0.2-0.4 µm Reticulatebodies- replicative, 0.6-1.5 µm Chlamydia trachomatis PUBLIC / CYHOEDDUS Trachoma, STD Trachoma- rough eyelids leading to corneal breakdown; blindness; spread through contact with eyes/nose STD- spread through sexual activity; genital discharge, vaginal bleeding, painful urination; more common in young adults Classifying Prokaryotes PUBLIC / CYHOEDDUS Domain Bacteria Domain Archaea Gram Negative Gram Positive PseudomonadotaNon-Pseudomonadota Enteric Bacteria Cyanobacteriota Salmonella Spirochetota Treponema Yersinia pestis palladium Non-enteric Bacteria Bacteroidota Vibrio fischeri Alistipes Bdellovibrio Caulobacter Chlamydiota Chlamydia trachomatis  PUBLIC / Leaning Outcomes CYHOEDDUS Briefly describe the Linnaeus classification system and how it applies to Prokaryotes Be able to correctly write Latin names of organisms List some of the major lineages of Bacteria Give detailed examples of some of the Pseudomonadota and Non-Pseudomonadota Understand how these groups fit into the prokaryotic tree of life  PUBLIC / Extra Reading CYHOEDDUS Tortora Chapter 11 (the section on Gram Negative Bacteria) Bauman Chapter 11 (Modern Prokaryotic Classification) Bauman Chapter 21- Rickettsias, Chlamydias, Spirochetes and Vibrios Open access book chapter Pseudomonadota Open access book chapter Non-Pseudomonadota