BIOL 452 Marine Symbiosis

Pea aphid

• symbiont: Buchnera aphidicola

• intracellular endosymbiont

• vertical transmission through mother

• pea aphid feeds on plant sap phloem which lacks essential amino acids, Buchnera synthesizes these amino acids for the host

• obligate mutualism, over time Buchnera has lost around ~86% of its genome through being an intracellular symbiont (may be considered an organelle)

Dental films

• 1970 discovery by Gibbons and Nygaard

• example of cooperation

• strains aggregate and sink to the bottom of a test tube when together

• allows for an expanded habitat range, horizontal gene transfer, resistance to antimicrobials, protection from predation (only top layer is exposed), and an increase in metabolic diversity (1 bacteria’s waste product is a reactant for another)

Proteus mirabilis

• host: humans

• extracellular endosymbiont

• HORIZONTALLY transmitted through ingestion of food

• normally found in the gut (COMMENSAL)

• can also accumulate in coastal areas in high numbers as filter feeders (COMMENSAL)

• anywhere else it is found in the body it is PARASITIC

• demonstrates swarming motility IN HUMANS which has never been observed before in nature

• is halotolerant (can live in high salt conditions)

• is a conditional pathogen

Myxococcus xanthus

• is a soil bacterium

• secretes extracellular enzymes to digest prey from the outside utilizing “wolf pack predation”, aka multiple cells need to be secreting the enzyme for this to be successful

  • AN EXAMPLE OF PREDATION

Bdellovibrio

• rams target cells at 100 cell lengths per second

• high swimming speed allows encounter with prey and entry through the membrane, whilst it remains in the periplasm where it releases enzymes that loosen peptidoglycan in the cell wall, causing the cell to form a spherical “bdelloblast” inside of it that expands as the bdellovibrio replicates inside of it, eventually causing the host cell to lyse and the new bdellovibrios to be released

• example of PREDATION

Toxoplasma gondii

• host: rats, mice, cats, humans

• OBLIGATE INTRACELLULAR, EXTRACELLULAR only after cells have been lysed

• VERTICAL transmission from mother to fetus across placenta, HORIZONTALLY transmitted when coming into contact with infected food, animals, or water

• a protozoa parasite

• infects warm blooded animals

• causes toxoplasmosis which alters behaviors in rats and mice

• can cause psychotic symptoms in humans, has been linked to schizophrenia

Lichen (regular)

• a single fungi with cyannobacteria or algae

• is EDIBLE to mammals

• help form a structural niche that individual symbionts cannot make

• fungal nyphae protect photosynthetic partner from dessication (drying out)

• photosynthetic partner provides fungi with fixed carbon

• long term (~400 million years)

Lichen (toxic)

• consists of a single fungi, a cyannobacteria or algae, and a fungal yeast (causes toxicity)

• is NON-EDIBLE to mammals

  • performed metatranscriptomics (study of mRNA) in each of the lichen to see why one was toxic and one was not, got lots of mRNA FOR FUNGAL YEAST in the toxic lichen

Vibrio fischeri (main)

• host Euprymna scolopes (squid found off coast of Hawaii)

• EXTRACELLULAR ENDOSYMBIONT

• HORIZONTALLY TRANSMITTED

• COOPERATION

• utilizes quorum sensing through secretion of acyl-homoserine lactones (AHL) also called AUTO INDUCERS, once enough auto inducer molecule has collected the threshold is met and bioluminesence occurs

• host benefits as their shadow from the moon at night is disrupted, keeping them protected from prey

• symbiont benefits by getting nutrients from the host

Vibrio fischeri - interference competition

• when the symbiont has entered the light organ of the squid, they compete with one another through utilizing T6SS because only 1-2 colonizer cells can occupy each crypt

Vibrio fischeri (Fish)

• host: zebra fish

• EXTRACELLULAR ENDOSYMBIONT

• PARASITIC

• horizontally transmitted

• causes blood pooling, necrotic tissue, morphological issues

Vibrio fischeri (Artemia)

• host: Artemia (brine shrimp)

• EXTRACELLULAR ENDOSYMBIONT in gut

• PARASITIC

• dose dependent effect, the more vibrio added to the treatment, the more brine shrimp killed

Poribacteria

• Host: Sponge

• may be ancient VERTICALLY TRANSMITTED symbiont

• MOST PREDOMINANT bacteria in sponges, may consume the host matrix

• is not culturable

NW001

• host: sponges

• VERTICAL TRANSMISSION

• EXTRACELLULAR ENDOSYMBIONT

• is 75-90% of the culturable community in a sponge

• is a COMMENSAL

NW4327

• host: Sponge

• HORIZONTAL TRANSMISSION

• PARASITIC

• agent of disease in Great Barrier Reef Sponges

• burrows through spongin matrix

Hymeniacidon perlevis

• host: sponge

• HORIZONTAL TRANSMISSION

• PARASITIC (virus)

Enthotheonella

• host: Theonella swinhoei, sponge native to Phillipenes, Indonesia, Japan, Northern Australia

• ENDOSYMBIOTIC EXTRACELLULAR

• HORTIZONTAL TRANSMISSION

• a filamentous bacteria in the mesophyl of the sponge that assists with digestion

Discodermolide

• host: Discodermia dissoluta

• host is a deep sea sponge found to produce discodermolide, a molecule that kills cancer cells by stabilizing microtubules to prevent cell division

• hard to replicate this molecule because it is hard to synthesize the correct isomer, is at low concentrations in the cell but seems to accumulate on the surface seeming as if it may be used to protect against predation

Saprospira

• host: Diatom

• HORIZONTALLY TRANSMITTED

• PARASITIC

• invades the host INTRACELLULARLY and causes the host to lyse

Amphiprora Kufferathii (Ice Diatom)

• ice diatom is the host

• symbiont: ECTOSYMBIOTIC bacteria

• HORIZONTAL TRANSMISSION

• detoxify hydrogen peroxide with catalase

• diatoms grow better with their epibionts

Endoriftia persephone

• host: Riftia (giant tube worm)

• EXTRACELLULAR ENDOSYMBIONT

• HORIZONTAL TRANSMISSION through larvae (even though this is an obligatory nutritional dependence!!!!!)

• riftia does not have a digestive tract, rather the bacteria occupy the trophosome and are chemosymbiotic meaning they oxidize sulfide to provide the host with usable forms of energy

Stapholococcus

• host: sharks

• HORIZONTAL TRANSMISSION

• EXTRACELLULAR ENDOSYMBIONT

• in AoL jelly, most prominent bacterial culture

214IT-like sulfur oxidizing bacteria

• host: Giant Shipworm

• EXTRACELLULAR ENDOSYMBIONT

• found in the gills of the giant shipworm, is a chemosynthetic bacteria that helps supply the giant shipworm with energy

Xylotrophic bacteria

• host: shipworms (regular)

• EXTRACELLULAR ENDOSYMBIONT

• produces enzymes that helps the shipworm digest cellulose and lignin from wood ingested whilst boring holes with shell

Mycobacterium marinum

• host: variety of fish (Coho salmon and Sparus aurata)

• PARASITIC

• ENDOSYMBIOTIC

• HORIZONTALLY TRANSMITTED

• causes granulomas, worth studying because it is very similar to tuberculosis, nicknamed TB of the sea

Vibrionaceae

• host: Sharks

• HORIZONTALLY TRANSMITTED

• PARASITIC (only found on wound sites of the sharks that were sampled

Moraxellaceae

• host: sharks

• found on all shark species sampled

Proteobacteria

• host: sharks

• most abundant PHYLUM of bacteria found on sites sampled from all over different sharks bodies

Ascomycota, Alveolata, and Radolaria

• host: Sponge

• core community bacteria