Animal-Plant Connections
Traits/Genes conserved between animals and plants
Contents
LUCA - Last Universal Common Ancestor
3.5-4.5 billion years ago
...it can be studied by comparing the genomes of all modern organisms, its descendants. The genes describe a complex life form with many co-adapted features, including transcription and translation mechanisms to convert information from DNA to RNA to proteins. A study concluded that the LUCA probably lived in the high-temperature water of deep sea vents near ocean-floor magma flows.
While the gross anatomy of LUCA can only be reconstructed with much uncertainty, its biochemical mechanisms can be described in some detail, based on the "universal" properties currently shared by all independently living organisms on Earth.
https://en.wikipedia.org/wiki/Last_universal_common_ancestor
mitocondria?
- Kreb's cycle? no use of oxygen but does produce CO2, products go into the respiratory cycle (also in the mitiochondria)
- Its central importance to many biochemical pathways suggests that it was one of the earliest components of metabolism and may have originated abiogenically [wikipedia]
- In eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion. In prokaryotic cells, such as bacteria, which lack mitochondria, the citric acid cycle reaction sequence is performed in the cytosol with the proton gradient for ATP production being across the cell's surface (plasma membrane) rather than the inner membrane of the mitochondrion. [ibid]
Mitochondria play a central role in many other metabolic tasks, such as:
- Signaling through mitochondrial reactive oxygen species[65]
- Apoptosis-programmed cell death[66]
- Certain heme synthesis reactions
- ...
Mitochondrial diseases: https://en.wikipedia.org/wiki/Mitochondrial_disease
glyoxalate cycle
- The glyoxylate cycle, a variation of the tricarboxylic acid (Kreb's) cycle, is an anabolic pathway occurring in plants, bacteria, protists, and fungi.
- In plants the glyoxylate cycle... allows seeds to use lipids as a source of energy to form the shoot during germination. The seed cannot produce biomass using photosynthesis...
- The glyoxylate cycle may serve an entirely different purpose in some species of pathogenic fungi. The levels of the main enzymes of the glyoxylate cycle, ICL and MS, are greatly increased upon contact with a human host. Mutants of a particular species of fungi that lacked ICL were also significantly less virulent in studies with mice compared to the wild type. The exact link between these two observations is still being explored...
- Vertebrates were once thought to be unable to perform this cycle... However, some research suggests that this pathway may exist in some, if not all... Specifically, some studies show evidence of components of the glyoxylate cycle existing in significant amounts in the liver tissue of chickens... Other experiments have also provided evidence that the cycle is present among certain insect and marine invertebrate species, as well as strong evidence of the cycle's presence in nematode species. However, other experiments refute this ... publications conflict on the presence of the cycle in mammals... Evidence exists for malate synthase activity in humans due to a dual functional malate/B-methylmalate synthase of mitochondrial origin called CLYBL expressed in brown fat and kidney.[14] Vitamin D may regulate this pathway in vertebrates.
- It is believed by some that the genes to produce these enzymes, however, are pseudogenic in mammals, meaning that the gene is not necessarily absent, rather, it is merely "turned off"
hemoglobin vs chlorophyl?
Both are porphyrins - https://en.wikipedia.org/wiki/Porphyrin
- Porphyrin coordinated to magnesium: chlorophyll
- Porphyrin coordinated to iron: heme
- A heme-containing group of enzymes: Cytochrome P450 (liver breakdown of drugs)
- The one-carbon-shorter analogues: corroles, including vitamin B12, which is coordinated to a cobalt
- Corphins, the highly reduced porphyrin coordinated to nickel that binds the Cofactor F430 active site in methyl coenzyme M reductase (MCR)
- Nitrogen-substituted porphyrins: phthalocyanine - blue pigment, etc.
- A porphyrin-related disease: porphyria
One Ring in the Colors of Life - https://www.americanscientist.org/article/porphyrins-one-ring-in-the-colors-of-life
- The porphyrin pathway is ubiquitous in the biological realm, serving throughout the plant and animal kingdoms as the assembly line for the most abundant pigments in nature. The ring-shaped porphyrin molecules bind an array of metal ions, with each combination associated with different biological functions. Chlorophylls bind magnesium to play a pivotal role in photosynthesis. Heme binds iron to coordinate molecular oxygen and carbon-dioxide transport, supports the electron-transport chains necessary for cellular respiration and contributes to the catalytic activities of many enzymes. Porphyrins bind nickel to form coenzyme F430, which plays critically important roles in bacteria that metabolize methane. Vitamin B12 is formed from the binding of cobalt to a derivative of porphyrin
- The early porphyrin precursors differ between plants and animals, but they converge at the first committed molecule in the chain of synthesis, delta-aminolevulinic acid. And the subsequent steps involved in the synthesis pathway are universal... Protoporphyrinogen oxidase is the last enzyme before a major branching point in the synthesis of the “rings of life.” The next step finds enzymes catalyzing the binding of various metal ions to protoporphyrin, committing the master ring to the synthesis of an array of biologically important molecules.
anti-oxidants?
Autolysis
Failure of respiration and subsequent failure of oxidative phosphorylation is the trigger of the autolytic process
- Molecular oxygen serves as the terminal electron acceptor in the series of biochemical reactions known as oxidative phosphorylation
- Glycolysis has a lower ATP yield than oxidative phosphorylation and generates acidic byproducts that decrease the pH of the cell, which enables many of the enzymatic processes involved in autolysis
- Water retention, ionic changes, and acidification of the cell damages membrane-bound intracellular structures including the lysosome and peroxisome
- Lysosomes are membrane-bound organelles that typically contain a broad spectrum of enzymes capable of hydrolytic deconstruction... This process requires compartmentalization and segregation of enzymes ... that prevents unwarranted destruction of other intracellular components... further protected from lysosomal enzyme activity by regulation of cytosolic pH. The activity of lysosomal hydrolases is optimal at a moderately acidic pH of 5, which is significantly more acidic than the more basic average pH of 7.2 in the surrounding cytosol...the accumulation of products of glycolysis decreases the pH of the cell, reducing this protective effect. Furthermore, lysosomal membranes damaged by water retention in the cell will release lysosomal enzymes into the cytosol...
- Peroxisomes typically are responsible for the breakdown of lipids... In the absence of an active electron transport chain and associated cellular processes, there is no metabolic partner for the reducing equivalents in the breakdown of lipids. In... autolysis, peroxisomes provide catabolic potential for fatty acids and reactive oxygen species, which are released into the cytosol as the peroxisomal membrane is damaged...
- The release of catabolically active enzymes from their sub-cellular locations initiates an irreversible process that results in the complete reduction of deceased organisms. Autolysis produces an acidic, anaerobic, nutrient-rich environment that nurtures the activity of invasive and opportunistic microorganisms in a process known as putrefaction. Autolysis and putrefaction are the main processes responsible for the decomposition of remains.
- per wikipedia - https://en.wikipedia.org/wiki/Autolysis_(biology)
Oxidative phosphorylation
In contrast to the general similarity in structure and function of the electron transport chains in eukaryotes, bacteria and archaea possess a large variety of electron-transfer enzymes. These use an equally wide set of chemicals as substrates. In common with eukaryotes, prokaryotic electron transport uses the energy released from the oxidation of a substrate to pump ions across a membrane and generate an electrochemical gradient...
The main difference between eukaryotic and prokaryotic oxidative phosphorylation is that bacteria and archaea use many different substances to donate or accept electrons. This allows prokaryotes to grow under a wide variety of environmental conditions. In E. coli, for example, oxidative phosphorylation can be driven by a large number of pairs of reducing agents and oxidizing agents
Molecular oxygen is an ideal terminal electron acceptor because it is a strong oxidizing agent. The reduction of oxygen does involve potentially harmful intermediates... These reactive oxygen species and their reaction products, such as the hydroxyl radical, are very harmful to cells, as they oxidize proteins and cause mutations in DNA...
... To counteract these reactive oxygen species, cells contain numerous antioxidant systems, including antioxidant vitamins such as vitamin C and vitamin E, and antioxidant enzymes such as superoxide dismutase, catalase, and peroxidases, which detoxify the reactive species, limiting damage to the cell
There are several well-known drugs and toxins that inhibit oxidative phosphorylation. Although any one of these toxins inhibits only one enzyme in the electron transport chain, inhibition of any step in this process will halt the rest of the process... As a result, the proton pumps are unable to operate... NADH is then no longer oxidized and the citric acid cycle ceases to operate...
Synthesis of ATP is also dependent on the electron transport chain, so all site-specific inhibitors also inhibit ATP formation. The fish poison rotenone, the barbiturate drug amytal, and the antibiotic piericidin A inhibit NADH and coenzyme Q.
Carbon monoxide, cyanide, hydrogen sulphide and azide effectively inhibit cytochrome oxidase. Carbon monoxide reacts with the reduced form of the cytochrome while cyanide and azide react with the oxidised form. An antibiotic, antimycin A, and British anti-Lewisite, an antidote used against chemical weapons, are the two important inhibitors of the site between cytochrome B and C1.
per wikipedia - https://en.wikipedia.org/wiki/Oxidative_phosphorylation
Slime Molds?
Liverwort
metabolism? Spore production? Oxidation stress? ancestry? relatives?
Honeycomb
Livido reticularis
"...a lace-like purplish discoloration of the skin. The discoloration is caused by reduction in blood flow through the arterioles that supply the cutaneous capillaries, resulting in deoxygenated blood showing as blue discoloration. This can be a secondary effect of a condition that increases a person's risk of forming blood clots, including a wide array of pathological and nonpathological conditions. Examples include hyperlipidemia, microvascular hematological or anemia states, nutritional deficiencies, hyper- and autoimmune diseases, and drugs/toxins." https://en.wikipedia.org/wiki/Livedo_reticularis
Another good illustration, article explains that blockage of either the arterioles or the venules can cause a reticular pattern. https://plasticsurgerykey.com/other-vascular-disorders/
Erythema ab igne
"...a skin condition caused by long-term exposure to heat (infrared radiation).[3] Prolonged thermal radiation exposure to the skin can lead to the development of reticulated erythema, hyperpigmentation, scaling and telangiectasias in the affected area. Some people may complain of mild itchiness and a burning sensation, but often, unless a change in pigmentation is seen, it can go unnoticed."
"The pathogenesis of erythema ab igne remains unknown. It has been proposed that thermal radiation exposure can induce damage to superficial blood vessels that subsequently leads to epidermal vascular dilation. The dilation of vessels presents morphologically as the initially observed erythema.[4] Red blood cell extravasion and deposition of hemosiderin that follows clinically appears as hyperpigmentation, which can occur in a reticular distribution. It has also been proposed that the distribution of affected blood vessels — predominantly in the superficial subcutaneous plexus (found in the papillary dermis)— results in the net-like pattern of erythema ab igne skin lesions." https://en.wikipedia.org/wiki/Erythema_ab_igne
