Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

B3.0 > Cellular Evolution Of Microbial Eyes > Flashcards

Cellular Evolution Of Microbial Eyes Flashcards

1
Q

Eyes have evolved

A

All over the TOL!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do eyes work?

A
  • light occlusion/refractory layer
  • light sensing surface (rhodopsin proteins)
  • juxtaposition of 2 layers provides light detection and direction perception
  • light refracts off occlusion layer and hits light sensing surface
  • signals generate an action potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Eye core function

A
  • modified and elaborated on
  • vast diversity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

eye spots

A

Eye like systems also all over the TOL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Warnowiid microbial eyes

A
  • dinoflagellates, related to Symbiodinium
  • HUGE genome; visible under light microscopy; wrapped around liquid crystals
  • oscilloid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Oscilloid

A

Eye-like structure
- thought it was a squid eye that had become detached
- unculturable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Oscilloid organelles

A
  • TEM
  • retinal body
  • lens structure
  • cornea (crystal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Retinal bodies

A
  • isolation and micro dissection
  • mRNA amplification
  • high transcriptional enrichment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Oscilloid hypothesis

A
  • chloroplast derived?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

FIBSEM

A
  • focussed ion beam SEM
  • takes 100s of hours
    1. high pressure freeze
    2. SEM
    3. Laser a layer off
    4. Repeat 1.2.3
    5. Colour every cell section; builds a 3D structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

FIBSEM obs?

A
  • retinal body resembles plastid matrix, shaped around lens structure
  • ordered structures; compound eyes (rods and cones analog)
  • molecular convergence of organised photoreceptor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Proteome reconstruction

A
  • missing PSII; non-photosynthetic
  • retained some PS apparatus
  • generates proton/ion gradients across membranes
  • proton pumps generate proton gradients through ETCs (may not support ATP synthesis); cyclic EF
  • drives action potential (light driven proton pump); similar to rhodopsins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can Warnowiid do without photosynthesis?

A
  • ecology!
  • under time-lapse
  • cell shoots harpoons/pistons under activation
  • snares a bacterium for consumption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Fungi?

A

Subcellular compartment: fungal zoospore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Blastocladiomycota

A
  • form phototactic zoospores
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Blastocladiella

A
  • RGC gene fusion
  • localised to SBC (visualised under Nile Red lipid stain)
  • pharmacological inhibition of R/GC domain inhibits phototaxis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

RGC

A
  • Rhodopsin guanylyl Cyclase
  • externalised along lipid droplet surface; forms rhodopsin layer
  • lipids refract the light
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

SBC

A
  • side body complex
  • lipid filled organelle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Animal light perception pathway

A
  1. Light triggers animal type II rhodopsin
  2. G protein transducer complex stimulates cGMP hydrolysis
  3. Na+ influx blocked via closure
  4. Membrane hyper polarisation
  5. Synaptic signalling
20
Q

Fungal light perception pathway

A
  1. Light triggers bacteria-type I rhodopsin
  2. Activates GC
  3. cGMP synthesis
  4. K+ channel opened
  5. Membrane hyperpolarisation
  6. Action potential activates flagellum beating
21
Q

Fungal light perception pathway

A
  1. Light triggers bacteria-type I rhodopsin
  2. Activates GC
  3. cGMP synthesis
  4. K+ channel opened
  5. Membrane hyperpolarisation
  6. Action potential activates flagellum beating
22
Q

Chytrids

A
  • possess a wide range of functionally diversified RGC paralogs
  • homo and heterodimers
  • gene duplications
  • can detect wide range of wavelengths
  • optogenetics!
23
Q

Chloroplasts

A

W red colourisation ; uses rhodopsin layer

24
Q

Opsin

A
  • can modify highly cell- spatial- or temporal- specific neutral networks
  • microbial derived
  • can be used in optogenetics
  • introduced after a promoter region by a viral carrier
25
Q

Optogenetics

A
  • Different light wavelengths are used to initiate neuronal activation/inhibition or receptor-mediated intercellular signalling
  • a useful biotechnology and neurobiological tool
26
Q

How does optogenetics work?

A

Illumination is delivered to the skull cortex by light delivery to an optic fibre, stabilised by an optic canyon and cranioplastic cement

27
Q

Blue light

A
  • Triggers ChR2 to rapidly depolarise a neurone
  • generates an action potential throughout mono and Divalent cation permeability
28
Q

ChR2

A

Channel rhodopsin 2

29
Q

Optogenetics basics

A
  • type I bacterial rhodopsin and GC domain fusion protein are expressed in animal cells
  • induces cGMP into an action potential
  • tuneable to a range of wavelengths
30
Q

GC domain fusion protein

A

Cyl Op / RGC

31
Q

Chytrid fungi optogenetics network

A

Highly distributed

32
Q

Under comparative analysis of zoospore cellular structures, reconstructing evolution shows

A

An adaptive radiation of various microtubular forms

33
Q

How do eye-like systems translate into movement?

A

Tracking fungal zoospores:
1. Hundreds of Rhizoclasmatium globosum
2. One Chytriomyces hyalinus

34
Q

Swimming tracks

A
  1. B. emersonii (Blastocladiomycota): random walking
  2. S. punetatus (Chytridiomycota); random walking
  3. R. globosum (Chytridiomycota); circular pattern
35
Q

Analysing swimming tracks

A
  • reorientation angle distribution / mean^2 displacement
  • shorter and longer timescale motility dynamics vary across groups
36
Q

A relationship between cytoskeleton and swimming tracks?

A

Confocal image

37
Q

Confocal imaging

A
  • 4x Blastocladiomycota, 8x Chytridiomycota
  • random walkers: prominent tubulin cytoplasmic structures
  • circular swimmers: N/A
  • nocodazole creates circular swimmers
38
Q

Nocodazole

A
  • microtubule pharmacologic
  • M: cytoskeleton ablation, diffuse cell, eye organelle collapse
39
Q

Cytoskeleton is

A

Necessary

40
Q

B. emersonii

A
  • random walker
  • resembles a light-activated, subcellular “muscle”
  • phototactic
  • uniformly turns towards eye organelle
41
Q

B. emersonii EM:

A
  • shows cell system diversification across evolution
  • Chytridiomyces comferrae: MLC
  • B. emersonii: SBC
42
Q

MLC

A

microbody-lipid globule complex

43
Q

Ultrastructure expansion microscopy (UExM)

A

1) parasite sedimentation (+/- fixation)
2) cross linking prevention: anchoring
3) gelation
4) denaturation
5) 1st expansion round
6) gel shrinkage, immunostaining
7) final expansion round, imaging

44
Q

UExM observations

A
  • Confocal
  • B. emersonii - random walking (tubulin and centrin)
  • Rhizoclosmatium globosum: circular swimming
  • microtubules join flagellum
  • lipid escape during expansion
45
Q

Spatial proteomics

A

1) cell fractionation
2) organelle fractionation
3) peptide generation and TMT labelling
4) high pH reversed phase UPLC
5) data analysis (protein distributions, pRoloc, supervised machine learning)

46
Q

tSNE plots

A
  • Be dLOPIT data; separate organelles emerge: rhodopsins next to each other; validation
47
Q

tSNE plots

A
  • Be dLOPIT data; separate organelles emerge: rhodopsins next to each other; validation

B3.0 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions