---
title: Cyanobacteria
disqus: hackmd
---
:::success
> Documentation [name=MrDr.Staffan]
###### tags: `Cyanobacteria`

### Table of Contents
[TOC]
:::
[Top](#Table-of-Contents)

[See slide booklet](https://docs.google.com/presentation/d/1rSC717r5lEG19ERc-aJD2hI8ZsWyA0uqM8a9_o39QR4/edit#slide=id.g2a7798c9cb0_0_62)

[See Evolution of life](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FPrWw0zxORH-l-9aPWufBVg#Cyanobacteria)

[See Plants](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FWBq2T9QhQ02n0rFMoZWgfg#Cyanobacteria)

[See References - Themes - Cyanotoxins](https://docs.google.com/spreadsheets/d/1-1lBW21bMPquA8P5VCRHNBahMASEhBCkE1N81bPyQ_k/edit#gid=850293993&range=A3)

[See Slide - Cyanotoxins](https://docs.google.com/presentation/d/11ewNQ9HE9UQ0V5gQ5rLaZBpeIZYpygta1c5Cy-v36qA/edit#slide=id.p)

*Why this page*
[Taking the cyanobacterial orgin of all life is criticial to include as a starting point. Many of those compounds specific to these species/families? are extremely potent toxins to humans and animals. this may be a reflection of their fundamental role in all life. "fitting that early machinery" and also must have been in competition with those early eukaryotes.]
[Another criticial point is we almost entirely lack techniques and tools for studying the mechanisms involved. Hence any development in this area would be of potentially great impact on a wide spectrum of fields studying living systems.]

["The question is not why these are toxic to humans/nervous system - the question is, why are these not toxic to the cyanobacteria that produce them? And what function do they perform? - toxicity always is secondary"]

[The function they perform, might very well be why they are toxic to todays more indirect life.
Life used to be direct. Energy to ground. Now its complicated.]

*what Do people want?*

Furthermore, studies are required to develop a mechanistic understanding of chronic, low-dose exposure to HAB toxins so that appropriate preventative, diagnostic, and therapeutic strategies can be created in a targeted fashion.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8950847/

"strengthening the bridge between De facto biologyJag on one side and medicine, synthetic and engineered biology on the other hand."

# "News"

Now, writing in Nature Climate Change, Kai Wirtz and colleagues1 argue for the incorporation of phytoplankton active vertical migration as a key process that is ignored in most ocean ecological and biogeochemical models.

# Rnaseq study

2023I non-alcohol steatosis in liver
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10467139/

# Deep Cyanobacteria Layers
[Deep Cyanobacteria Layers: An Overlooked Aspect of Managing Risks of Cyanobacteria](https://pubs.acs.org/doi/10.1021/acs.est.2c06928)
Saskatoon study

# Ideas

Potential to study effects of cyanotoxins on astrocytes.

Studying early/current simple eukaryote defence mechanisms against cyanotoxicity.

**Processes**
- The effect of cyanotoxins on BBB
- Glutamate // excitotoxicity regulation.
- Inflammatory response.

**USP**
- Saskatchewan was where cyanotoxins where first identified?

**Need // Collaborations**
- Analytical methods for water.

**Experiment ideas**
- Cyano-slushy for identifying novel paths.
- ACM. Can astrocytes "clean"

"Focusing on using biochemical models and published research advance. Seeking synergies that have useful or explanatory power, rather than develop further scientific tools"

 


# studies

## Anatoxin-a exposed Pc12 cells.
The immediate early genes expression in the PC12 cells activated by anatoxin-a
https://pubmed.ncbi.nlm.nih.gov/15862019/

PC12 cells

c-fos and NGFI-A
under the same condition, the gene expression of c-jun and NGFI-B did not show any remarkable changes.

## various ekotoxins
https://pubmed.ncbi.nlm.nih.gov/33946968/

# Selling

## ENS // Cow
How is cyanobacteria affecting our enteric nervous system.

From cow to table.
ENS model.
ENS induced IPSC.
Collaborations

## Caseae

# To the rescue

This study established that plankton grazing can effectively reduce certain species of bloom-forming cyanobacteria while nutrient limiting strategies can eliminate others such as Microcystis.

# Links
[General toxicitiy - UK National Poisons Information Service and the Association for Clinical Biochemistry](https://journals.sagepub.com/doi/pdf/10.1177/0004563213519754)

[New Zealand - The Acute Toxicity and Biochemical Assessment of Anatoxin-a and Dihydroanatoxin-a](https://environment.govt.nz/assets/Publications/Files/Acute-toxicity-and-biochemical-assessment-of-ATX.pdf)

# Introduction
Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under high concentration of phosphorus conditions, they reproduce exponentially to form blooms.
The bacterium accounts for about 20% of the oxygen in the Earth's atmosphere.[46]
[As such cyanobacterial growth are currently provided for with agricultural run offs and increase in carbondioxide. This predicts we will have increasingly big problems until the balance of these compounds are in balance again. This is a very real albeit potential existential risk to human civilization. The motive for grant. potential impact. ]

Gram negative, i.e. has a peptideglyco envelope. but no cell wall.

Cyanobacteria are the first organisms known to have produced oxygen as a byproduct of photosynthesis.

Cyanobacteria are thought to have converted the early oxygen-poor, reducing atmosphere into an oxidizing one, causing the Great Oxidation Event and the "rusting of the Earth",[14] which dramatically changed the composition of life forms on Earth.[15]

Cyanobacteria are a group of photosynthetic bacteria evolutionarily optimized for environmental conditions of low oxygen.[22] Some species are nitrogen-fixing

Symbiotic relationship with plants or lichen-forming fungi (as in the lichen genus Peltigera).[23] They range from unicellular to filamentous and include colonial species. Colonies may form filaments, sheets, or even hollow spheres.

# Extinction events and cyanobacteria

https://www.nbcnews.com/id/wbna33541539

:::success
[](https://www.nature.com/articles/s41467-021-25711-3#author-information:~:text=Fig.%206%3A%20Phanerozoic%20mass%20extinctions%20with%20evidence%20of%20increased%20microbial%20abundances.)

Many species of Microcystis are known to produce secondary metabolites termed cyanotoxins. These secondary metabolites are often toxic to higher trophic organisms and pose an increased environmental risk to human and animal health. These toxic metabolites are classified into hepatotoxins, neurotoxins, cytotoxins, and dermatoxins [3]. For a more thorough review of these metabolites, Jones et al. describes the creation of an extensive and comprehensive database named “CyanoMetDB” [13]
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8950847/

Est. 2019
https://www.eawag.ch/en/department/uchem/projects/cyanometdb/

open access database is a comprehensive collection of 2010 cyanobacterial metabolites as well as 99 structurally related compounds curated from 850 peer-reviewed articles published between 1967 and 2020

==some cyanobacterial strains exert toxic effects despite not producing any known cyanotoxins, thus indicating the presence of potentially unknown or uncharacterized toxins==

The first published report that blue-green algae or cyanobacteria could have lethal effects appeared in Nature in 1878.

Cyanotoxins are toxins produced by cyanobacteria (also known as blue-green algae). Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under high concentration of phosphorus conditions, they reproduce exponentially to form blooms. Blooming cyanobacteria can produce cyanotoxins in such concentrations that they can poison and even kill animals and humans. They bioaccumulate in certain animals.

Exposure to the cyanobacteria neurotoxin BMAA may be an environmental cause of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Parkinson's disease, and Alzheimer's disease.[2]
[This is an excellent point for writing a grant to study these systems in neurodegeneration]

[A seemingly good example is Amino Acid alternative, BMAA which affect the Nervous System. It has a striking similarity to methionine, that it primarily is classified to affect the nervous system might be because of methionines higher rate in the brain?]
:::

## Prokaryotes - no cell nuclei
No nuclei,
no mitochondria,
But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: Bacteria (formerly Eubacteria) and Archaea (formerly Archaebacteria). Organisms with nuclei are placed in a third domain, Eukaryota.[5] Prokaryotes evolved before eukaryotes.

## Peptide nucleic acids "PNA".
[See NRPs - PNAs](https://hackmd.io/@sholmqvist/BJpKurTBB/%2Fkuws1ReMQvK9WrT-C9et5Q#Peptide-nucleic-acid)

Peptide nucleic acid (PNA)

These are not found in complex organisms. But are produced by some cyanobacteria.


pseudopeptide skeleton, composed of N-(2-aminoethyl)glycine unitsI [sminiethyl and glycine as main ash]

## GNAs
However, due to its simplicity, it might have played a role in the evolution of life

# Blooms
[2021 Bacterial Blooms: The social life of cyanobacteria](https://elifesciences.org/articles/70327)


Figure 1. Collective behaviour and lifestyle choices in single-celled cyanobacteria. Bacteria can stay in suspension as individual cells, adhere collectively to surfaces to form biofilms, passively sediment, or flocculate to form suspended aggregates. Cyanobacteria are able to produce sulphated polysaccharides (yellow haze surrounding clumps of cells) that enable them to form floating aggregates. Maeda et al. discovered that the oxygen produced by the cyanobacteria becomes trapped in the network of polysaccharides and cells, enabling the microorganisms to form buoyant blooms. It is thought that specific protein fibres known as pili (represented as lines radiating from the cells) may act as an additional way to link cells to each other or onto surfaces. Some cyanobacteria also use sophisticated intracellular gas vesicles as floating aids.

# Blooms and climate change?

[the connection between climate change and increase in occurrence of blooms is a topic debated]

2021 Perceived global increase in algal blooms is attributable to intensified monitoring and emerging bloom impacts
https://www.nature.com/articles/s43247-021-00178-

2023 Coastal phytoplankton blooms expand and intensify in the 21st centur
https://www.nature.com/articles/s41586-023-05760-y

[Reported CorrelationsJag of blooms with previous mass extiction events Over geological time must encourage favoring a cautionary interpretation of current and imminent developments]

# Impact on aquatic animal populations

For example, in 2019, a bloom dominated by the ichthyotoxic haptophyte, Chrysochromulina leadbeateri, occurred in the Nordic fjords and was accompanied by the death of around seven and a half million farmed Atlantic salmon, Salmo salar, valued at over US$90M [27].

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9147682/

"impairment of sensory-motor function"

"Reduced motility and ATP content of sperm"

"increased oocyte mortality & reduced fertilization success"

"behavioural changes, poor co-ordination, inactivity, oxidative stress and histological changes in adults, and: reduced hatching, swimming activity, growth & feeding of larvae"

"changes in immune functions, reduced escape locomotion and paralysis"

"lysosomal destabilization"

# Cyanobionts

# Cyanotoxins
[See Plants](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FWBq2T9QhQ02n0rFMoZWgfg#Cyanobacteria)


**Contact irritants**
aplysiatoxins
lipopolysaccharides
lyngbyatoxins
*oscillatoxins*

**Neurotoxins**
antillatoxins
kalkitoxin
N-sulfocarbamoyl
saxitoxins
gonyautoxin-3

**Hepatotoxins**
cylindrospermopsin
microcystins
motuporin // **Nodularin-V**
Nodularin

## Anabaenopeptins
Spoof et al., the researchers have isolated and identified new bioactive, cyclic hexapeptides—Anabaenopeptins—from a cyanobacterial bloom extract in the Baltic Sea and found the compounds to inhibit the activity of protein **phosphatase 1** and **carboxypeptidase A** but no inhibition of chymotrypsin, trypsin, or thrombin [18]

CPA1...?
PPP1C...?
Dusp1?
Pp1 & pp2a (ptpa)

## Anatoxin-a

ATX-a, also known as Very Fast Death Factor, is a secondary, bicyclic amine alkaloid and cyanotoxin with acute neurotoxicity. It was first discovered in the early 1960s in Canada, and was isolated in 1972. It is a nicotinic acetylcholine receptor ligand

[2017 Toxic Effects Produced by Anatoxin-a under Laboratory Conditions: A Review](https://www.mdpi.com/2072-6651/14/12/861)
Universidad de Sevilla, Spain.


<iframe style="width: 500px; height: 300px;" frameborder="0" src="https://embed.molview.org/v1/?mode=balls&cid=431734"></iframe>

250ug/kg LD50

For comparison
VX 140ug
[ ](https://en.wikipedia.org/wiki/VX_(nerve_agent))
Fentanyl 50ug

arsenic (As)
13mg/kg

https://en.wikipedia.org/wiki/Median_lethal_dose

https://sci-hub.se/10.1016/j.scitotenv.2020.139515

## Anatoxin // Guanitoxin
Guanitoxin (GNT), formerly known as anatoxin-a(S) "Salivary"


<iframe style="width: 500px; height: 300px;" frameborder="0" src="https://embed.molview.org/v1/?mode=balls&cid=114989"></iframe>

## 2-Amino-butyric Acid
2,4‐Diaminobutyric Acid
"Lysine two carbon shorter"
"Ornithine one carbon shorter"

non-proteinogenic alpha-amino acid

See 5-aminovalerate? // 5-Aminovaleric acid

Beyond being a general waste product, 5-aminovalerate is also believed to act as a methylene homologue of gamma-aminobutyric acid (GABA) and functions as a weak GABA agonist (PMID:4031870

**N-trimethyl**-5-aminovalerate as the best set of variables to predict development of microalbuminuria

## Kalkitoxin - Neuro


Like antillatoxin - Neuro
induces NMDA receptor mediated neuronal necrosis, blocks voltage-dependent sodium channels, and induces cellular hypoxia by inhibiting the electron transport chain (ETC) complex 1.

kalkitoxin neurotoxicity is mediated by an
N-methyl-D-aspartate receptor mechanism but the delayed toxicity suggests that this
may be due to a secondary endogenous excitotoxic mediator (Berman et al., 1999).

## BMAA

β-Methylamino-L-alanine

BMAA is a non-proteinogenic amino acid produced by cyanobacteria and cycads. It is considered a possible cause of ALS/PDC (amyotrophic lateral sclerosis/parkinsonism–dementia complex) and its toxicity has been associated with possible chronic neurodegeneration. It is classified as a neurotoxin

High concentrations of BMAA are present in shark fins.[11]

Cycad Seeds -> Flying foxes

[See Glutathione and Cathepsin](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FsZITyKgiSTGGEHEpKig2cw#Glutathione-amp-Cathepsin)

[See Ca2+](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FuAtidaIiS6qqdMBPI4CLNA#Calcium-and-cathepsin)


"β-N-methylamino-L-alanine (BMAA) is a potential neurogenerative disease agent (Han et al., 2020). The accumulation of cyanotoxins in plants other than MCs and CYN is minimally studied, and their uptake mechanisms are unknown."

Although the mechanisms by which BMAA causes motor neuron dysfunction and death are not entirely understood, current research suggests that there are multiple mechanisms of action. Acutely, BMAA can act as an excitotoxin on glutamate receptors, such as NMDA, calcium-dependent AMPA, and kainate receptors.

The activation of the metabotropic glutamate receptor 5 is believed to induce oxidative stress in the neuron by depletion of glutathione.[18]

[I would expect this to interfer by replacing the Cysteine in glutathione, plausibly interfering with antioxidation and H+ storage?]

[See Glutathione / N-acetyl-cysteine (NAC)](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FsZITyKgiSTGGEHEpKig2cw#Glutathione-Synthesis)

"BMAA can be misincorporated into nascent proteins in place of L-serine, possibly causing protein misfolding and aggregation, both hallmarks of tangle diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS), progressive supranuclear palsy (PSP), and Lewy body disease. In vitro research has shown that protein association of BMAA may be inhibited in the presence of excess L-serine".[19]

[Here its noteworthy that D-Serine is a co-activator of Glutamate receptors at the glycine binding site. Hence there is a plausible interaction of BMAA with NMDA receptors, portentialyl increasing the binding of glutamate - leading to excitotoxicity]
[Glycine<D-Serine<BMAA?]

[Potential link between GSS and PRNP prion protein in enteric glia?]

[If BMAA disrupt Cathepsin B then it can lead to problems in b-amyloid in Ca2+ wave cells.]

[See Glutathione and Cathepsin](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FsZITyKgiSTGGEHEpKig2cw#Glutathione-amp-Cathepsin)

[See Ca2+](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FuAtidaIiS6qqdMBPI4CLNA#Calcium-and-cathepsin)

[2022 - Weralupitiya - Sri Lanka - Cyanotoxins uptake and accumulation in crops: Phytotoxicity and implications on human health.](https://www.sciencedirect.com/science/article/abs/pii/S004101012200068X?via%3Dihub)

## DAB
DAB is a structural isomer of BMAA and is classified as a neurotoxin.


## Aetokthonotoxin - Bird
==Aetokthonos hydrillicola and the host plant it epiphytically grows on (most importantly hydrilla),
it took more than 25 years to identify aetokthonotoxin as the VM-inducing toxin after the disease has first been diagnosed in bald eagles in 1994==

[2004 Birrenkott Bowerman ESTABLISHING A FOOD-CHAIN LINK BETWEEN AQUATIC PLANT MATERIAL AND AVIAN VACUOLAR MYELINOPATHY IN MALLARDS (ANAS PLATYRHYNCHOS) ](https://meridian.allenpress.com/jwd/article/40/3/485/123567/ESTABLISHING-A-FOOD-CHAIN-LINK-BETWEEN-AQUATIC)

"Bromide is rarely mentioned in the biochemical context."

Aetokthonotoxin (AETX), colloquially known as eagle toxin

Genome sequencing of A. hydrillicola allowed the identification of the AETX biosynthetic gene cluster


In one specialized report, bromide is an essential cofactor in the peroxidising catalysis of sulfonimine **crosslinks in collagen IV**. This post-translational modification occurs in all animals and bromine is an essential trace element for humans.[20]

Something with 3d

The average concentration of bromide in human blood in Queensland, Australia, is 5.3±1.4 mg/L and varies with age and gender.[22] Much higher levels may indicate exposure to brominated chemicals. It is also found in seafood.

[2021 Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy](https://www.science.org/doi/10.1126/science.aax9050)

AETX is highly toxic to the nematode Caenorhabditis elegans [median lethal concentration (LC50) 40 nM] and zebrafish (Danio rerio; LC50 275 nM). Leghorn chickens (Gallus gallus) gavaged with AETX developed brain lesions characteristic of VM, whereas no lesions were observed in control chickens. VM diagnosis in treated chickens was verified using transmission electron microscopy of brain tissue.

[2012 How a Neurotoxin Survives](https://www.science.org/doi/full/10.1126/science.1219602)

[2022 From Tryptophan to Toxin: Nature’s Convergent Biosynthetic Strategy to Aetokthonotoxin](https://pubs.acs.org/doi/10.1021/jacs.1c12778)

<br><br><br>

# Those circles

<br><br><br>

## Microcystins

nonribosomal peptide

## Saxitoxin - Neuro

3D
human, intravenously - 0.6 μg/kg
human, oral - 5.7 μg/kg

<iframe style="width: 500px; height: 300px;" frameborder="0" src="https://embed.molview.org/v1/?mode=balls&cid=56947150"></iframe>


" Now, researchers have worked out how a suite of microbial enzymes can make the molecule less toxic, taking a first step toward biocatalytic development of new drugs based on saxitoxin and other shellfish toxins (ACS Chem. Biol. 2019, DOI: 10.1021/acschembio.9b00123)."

It acts by binding strongly to voltage-gated sodium channels that sit in cell membranes and initiate and transmit nerve signals.

Saxitoxin can also refer to the entire suite of more than 50 structurally related neurotoxins (known collectively as "saxitoxins") produced by protists, algae and cyanobacteria which includes saxitoxin itself (STX), neosaxitoxin (NSTX), gonyautoxins (GTX) and decarbamoylsaxitoxin (dcSTX).

"over-excites cells and blocks nerve impulses."

## Gonyautoxin

## Antillatoxin
https://en.wikipedia.org/wiki/Antillatoxin
 

Antillatoxin activates voltage-gated sodium channels, thus increasing sodium influx into the cell.

## Saxitoxin

11,11-Dihydroxy-N-sulfocarbamoylsaxitoxin

## Gonyautoxin-3

# Dom med roliga namn

## Cylindrospermopsin

CYN is a zwitterionic tricyclic alkaloid produced by a variety of freshwater cyanobacteria. It is a protein synthesis inhibitor, may be carcinogenic, and inhibits pyrimidine nucleotide synthesis. It is classified as a cytotoxin and hepatotoxin


CYN is a polycyclic uracil derivative

[protein and glutathione synthesis inhibitor
guanidinic alkaloid cylindrospermopsin (CYN)](https://www.sciencedirect.com/science/article/pii/S2214750015300974?via%3Dihub#:~:text=guanidinic%20alkaloid%20cylindrospermopsin%20(CYN))

## Oscillatoxin
Toxins from Blue-Green Algae:'
Structures of Oscillatoxin A and
Three Related Bromine-Containing Toxins

## Nodularin-V motuporin

## Nodularin

Nodularins are cyclic nonribosomal pentapeptides

# Cyanotoxins in drinking water
[2016 Cyanobacterial Toxins in Drinking Water Document for Public Consultation](https://www.canada.ca/en/health-canada/programs/cyanobacterial-toxins-drinking-water/cyanobacterial-toxins-drinking-water.html)

## Shikimate pathway
"only in plants."
For synthesis folates and aromatic amino acids (tryptophan, phenylalanine, and tyrosine). This pathway is not found in animal cells.

Investigations into anatoxin-a, also known as "Very Fast Death Factor", began in 1961 following the deaths of cows that drank from a lake containing an algal bloom in Saskatchewan.


[x What is known about how this works?]
[x How is this intersting?]

### Acetate pathway

**Åland Study**
https://www.regeringen.ax/sites/default/files/attachments/page/cyanotoxin-bioaccumulation-crops-final.pdf

"possible cyanotoxin bioaccumulation in terrestrial crops
when irrigated with cyanotoxin polluted water"

Rice, wheat, Corn affected?

![](https://hackmd.io/_uploads/SkLpoeMsn.png "BMAA" =100x)

β-Methylamino-L-alanine (BMAA)
BMAA is also associated with neurodegenerative disease.

## photosynthetic pigments,
[See Plants](https://hackmd.io/@sholmqvist/BJpKurTBB/%2FWBq2T9QhQ02n0rFMoZWgfg#Photosynthesis)

# Off topic
[thought experiment either on a global level or in a closed off jar]

[the question if cyanobacteria growth is affected by CO2 levels]
This would have implications for climate change.
[possibly a feedback loop where high oxygen is keeping cyanobacteria low. Very likely, since they were the initial producers]. This impels that with increasing co2 concentrations we would get more O2 production. It is totally likely that "modern /Eukaryotic plants" Are more efficient in creating oxygen at low co2 concentrations, and and better handle high O2 levels. These two types of O2 producing systems would then be in balance, with Eukaryotic plants keeping The cyanobacteria at bay, and due to keeping co2 low and oxygen high. "they work at a higher complexity Logical level" .

when animals grow this balance is upset. They produce co2 which favours the Cyanobacteria. As they are more dependent on high co2.

If life on earth indeed is like a lightning or combusting flame. It sure can flicker and both burn away as well as be snubbed out short. Steady wins the race.

# CyanoBacteria and insects

The functional relationship between aquatic insects and cyanobacteria: A systematic literature review reveals major knowledge gaps
https://www.sciencedirect.com/science/article/pii/S2772809923000552

[The fight and collaboration between the peroxisomes and the mitochondria.
The perixisome of the S0 Cell is from the S1, the bacteria is reduced to a giant peroxisome. With some other crap
"A cultivated reaction. one system shaping another occording to its purposefullness to the whole."]

# Toxicity and regulations
Se vetenskapsrådet

## Tropane

[Tropane](https://en.wikipedia.org/wiki/Tropane)

Tropane N Floats inside a sphere of carbon.

![image](https://hackmd.io/_uploads/BkPZtN5Oa.png "Tropane" =100x)

[Anatoxin-a](https://en.wikipedia.org/wiki/Anatoxin-a)

![image](https://hackmd.io/_uploads/S1jpOV9Oa.png "Anatoxin0-a" =100x)