Amoebozoa

Host amoeba (Gregariamoeba structurata)
Order: Tubulinids (Tubulinida)
Family: Amoebas (Amoebidae)
Habitat: almost everywhere, where there are temporary or long term reservoirs with the polluted water and low contents of oxygen.

Picture by Biologist

Sponges hardly endure the polluted water, therefore in human epoch the variety of freshwater sponges had sharply decreased, and organisms of other systematic groups had started to substitute them in their niche. Possible, as a consequence of this redistribution of roles in Neocene ecosystems colonial protozoans had evolved, that eat plankton and the weighed particles of 1 – 5 microns in size, living in eutrophic reservoirs. One of their representatives is host amoeba named because of some features of colony life.
The colony of host amoebas looks like a shapeless slimy crust of 0.01 – 0.05 mm thick on underwater objects – plants, stones and driftwood. The cell has the shape of flat cake; its diameter is about 70 microns, and height is approximately 10 microns. As against related forms, host amoeba has no its own shell.
In cytoplasm of these protozoans 2 species of symbiotes live: lophotrichous bacteria attached in deepenings of plasmalemma (at the encystment of the host cell they are located in vacuoles) and parasitic bacteria of the unknown origin, synthesizing folic acid for the host and having the important role in chemotaxis (they are able “to remember” a direction and to adjust the formation of pseudopods at this place). These symbiotes constantly live in vacuoles of host amoebas. At division of the cell they are distributed between daughter cells.
At the end of cell most removed from the substratum there is a large bunch of lophotrichous bacterial symbiotes, moving food objects closer. Near to this bunch the hyperactivity of cytoplasm is observed: pseudopods grow more often and phagocytosis proceeds more actively. Sated cells creep away deep into the colony. Amoebas use the bacterial symbiotes to create a current of water to vertically extended site of body.
These protozoans live in eutrophic reservoirs and consequently are periodically compelled to struggle against burying of colonies with the deposit. Host amoebas struggle against this adverse phenomenon in two ways. They mainly migrate through a layer of deposit, forming thus of a chain of cells following the “leader” cell (at this time the colony is frequently separated to some daughter ones). Otherwise they migrate, forming “guides” (one more species of the symbiotic bacteria producing a number of amino acids and determining behaviour of amoeba in many respects) that allow “to remember” the direction of movement, and the whole colony creep in this direction till 5 – 70 minutes following each other like caterpillars of pine processionary moth. If the layer of deposit is thin, cells creep through it upward in order to remain everytime at the border of two environments. In more serious cases the colony is had to migrate. Migration begins from occurrence of “leaders” to which cells at the edge of colony turn. Then the formation of chains of cells follows, and they search for more favorable conditions independently from each other. In this case amoebas alternate “a choice of direction” at which “leaders” replace each other, and the periods of straight crawling. At this time amoebas eat bacteria living in silt. During the migration colony frequently breaks up to some parts.
The second problem to which these protozoans face is a shortage of oxygen frequently happening in polluted reservoirs. Host amoebas struggle against it by the formation of planktonic settling forms. They have numerous bacterial symbiotes with flagella, facilitating the swimming (the direction of flagellae rotation can change to opposite one), and long “thorns” of cast away bacterial flagella, facilitating soaring in thickness of water. After the period of plankton life these protozoans can settle again on the ground or floating objects and form colonies.
The colony keeps the certain orderliness due to “skeleton”. The common “skeleton” of the colony represents friable enough construction of flagellae having polysaccharide chemical structure cast away by lophotrichian symbiotes with the insignificant addition of proteins. This “skeleton” also serves also as food stock for the whole colony.
Settling of host amoebas proceeds in two ways. In standard case this species is settled with the help of cysts which are not so steady, especially to drying, and are only temporary condition of the cell. Less often some amoebas “stick together” to the chain, grow long (about 20 – 40 microns) cross “hairs” representing modified bacterial flagella, and due to them get much better hydrodynamical characteristics. Such planktonic settling stages are formed at shortage of oxygen. The whole colony breaks up to set of such chains and “flies up”, leaving the substratum.
Sexual breeding in life cycle of host amoebas is absent. A free-floating stage can easily become a commensal of various aquatic animals, more often Daphnia species on which shell small temporary colonies of filterers are formed. Sometimes the floating stage gets on gills of fishes, and due to them can be transported to rather long distance. Cysts at this species are formed at approach of adverse conditions (food shortage and/or drying of reservoir), and do not endure complete drying, therefore they are kept only in places where silt keeps sufficient dampness. These protozoans are rather numerous and sometimes form in their habitats a kind of original tiny stromatolites.

This species of protists was discovered by Mutant, the forum member.

Glass-shelled drosarcella (Drosarcella vitrea)
Order: Arcellinida (Arcellinida)
Family: Arcellidae (Arcellidae)
Habitat: outskirts of Mediterranean basin.
Some amoebas known to humans were different from their relatives by the presence of a shell that protected them from external impacts. The shell could be formed by different ways: either by producing structural material (chitin, silica) by the cell itself or by deposition of phagocytized and undigested particles (usually mineral) on the cell surface.
In Neocene, the descendants of testate amoebas have mastered various ecological niches, but one species, the glass-shelled drosarcella, became a commensal of the insectivorous plant pitcher-leaved sundew.
This species is a descendant of Arcella genus, which had inhabited fresh water, including puddles and wetlands. It is a small (about 0.2 mm) amoeba that produces a bilayer test in the shape of a one-sidedly convex lens with an aperture underneath. The inner layer of the test is brown chitin (like in the ancestors), and it is covered with a layer of silica (silicon dioxide) from outside, which gives the amoeba’s test a glass shine and a reflective ability. There is an aperture in the bottom side of the test, with several pseudopodia protruding from it, which gives the amoeba a mushroom-like shape.
The reflective “glazed” test protects the amoeba from the sun of the Mediterranean basin, where this species finds food and moisture in the pitchers of the pitcher-leaved sundew. Climate drying, caused by closing of the Strait of Gibraltar and drying of the Mediterranean Sea, made this species to back off to such an unusual habitat. There, it eats from the sundew’s table, feedind on its prey. It creeps across the internal walls of a pitcher and down into the liquid – along the sundew’s hair and on floating captured prey. In order to avoid being digested by the plant’s digestive enzymes, the animal keeps in the topmost layer of the liquid, where the concentration of enzymes is the least. In the conditions of the Mediterranean basin, this amoeba lives almost exclusively in the trap leaves of the sundew.
Drosarcella reproduces by division. The cell partly “flows out” of the aperture, its nucleus and other organelles divide, and formation of a new test starts. In adverse conditions, the amoeba can form thick-walled cysts, which is preceded by full exiting of the cell from its test. The cysts are transmitted by insects.

This species of protists was discovered by Biolog, the forum member.
Translated by Biolog.

Purple megalosarcodina (Megalosarcodina purpurea)
Order: Arcellinida (Arcellinida)
Family: Megalosarcodines (Megalosarcodinidae)
Habitat: the Mediterranean hollow, hyperhaline swamps.
Hyperhaline swamps and lakes, formed in a hollow of former Mediterranean Sea, represent an extreme inhabitancy for live beings. Here, among white salt plains, only few species survive, which can adapt to presence of great amount of salt in water. But the ones managed to survive in such conditions, prosper and are virtually out of competition. Frequently the evolution of such organisms derivates freakish lifeforms.
Very large testate amoeba externally similar to fossil nummulites of Tertiary lives in hyperhaline water of Mediterranean swamps. It is purple megalosarcodina, a species of shell-bearing protozoans, making the separate family. Its size is measured in centimeters – it is a giant among protozoans. The size of flat disc-shaped shell of megalosarcodina is about 5 – 6 cm. The cell of this amoeba represents multinuclear syncytium (the number of nuclei is measured by thousands) having flat leaf-like shape. The shell is also flat and disc-like, made of carbonates. The surface of this shell has numerous small transparent crystal fenestellae. The shell grows in concentric circles along the edge. It is capable to regeneration, and as it grows, it also turns thicker in the middle due to accumulation of new layers of material. On the surface of the shell borders of the previous layers of increase are seen. After the dying off of megalosarcodinae their shells fall on the bottom of reservoir, forming deposits of limestone in ultrahaline swamps.
Numerous bacteria living in cytoplasm of purple megalosarcodina are extreme halophiles performing the photosynthesis by means of bacteriorhodopsine pigment. Due to their presence the amoeba has beautiful purple color. Symbiotic bacterium Rhodolampropedia hexagonalis is the direct descendant of bacterium Lampropedia. In human epoch purple bacteria of unusual cell shape – triangular or square (such cell shape Lampropedia had) lived in Dead Sea. Their descendant has cells of rectilinear hexagon shape. At very large width reaching two millimeters (in human epoch such bacteria had not been known) thickness of cell does not exceed one tenth of hair thickness. Bacteria form piles of cells like thylacoids in plant chloroplasts, and piles are stacked in cytoplasm of amoeba as honeycombs: the hexagonal shape of bacterial cells enables it. The shell of megalosarcodina has the cellular structure adapted to the best focussing of light penetrating through fenestrellae at the top side of shell.
Like all amoebas megalosarcodina has no strictly determined body shape. The cell forms pseudopods able to creep from shell in searches of food – mainly organic particles and bacteria. Pseudopods are supplied with the protective weapon – poisonous harpoons like infusorian trichocysts. Therefore water turtlebeetles, crustaceans and salt-loving skinkfishes do not eat megalosarcodina. Also megalosarcodina can stretch pseudopods in brightly lighted sites of the bottom in order to allow symbiotic bacteria to perform photosynthesis more actively – megalosarcodina receives from them an essential part of feeding, from time to time “attacking” very much multiplied symbiotes with digestive enzymes.
This species of protozoans breeds by means of cell division, and one half of former cell stays on shell, and another half forms its shell anew within several days. Megalosarcodina also has sexual process – merge of nuclei in cell with the subsequent division. Sexual process appears in adverse conditions, for example, at drying of the reservoir. This protozoan endures drought, closing shell apertures with secretions of glycoproteid nature and running into anabiosis. Bacteria thus turn to cysts. If adverse conditions are delayed, megalosarcodina gradually eats a part of symbiote cysts.
In favorable conditions, and also at some freshening of water (for example, during the rainy time) megalosarcodina breeds more intensively, separating pseudopods and other parts of the body. If division has taken place inside the shell, the daughter individual abandons it through one of apertures for pseudopods.
Accumulating fat drops in cytoplasm, purple megalosarcodina gets a side benefit, the buoyancy. Hyperhaline water helps to float, pushing out this animal to the surface. This way of movement is characteristic for younger individuals with rather lightweight shell. Larger animals with thick massive shell creep on the bottom.

This species of protists was discovered by Anton, the forum member.

Insect-eating droseroflugia (Droseroflugia insectivora)
Order: Arcellinida (Arcellinida)
Family: Difflugiidae (Difflugiidae)
Habitat: outskirts of Mediterranean basin.
Some testate amoebas known in the human era did not synthesize their tests themselves, but deposited undigested particles (usually mineral) captured by phagocytosis on the cell surface, where they were agglutinated by an organic matrix.
In Neocene, one of their descendants, the insect-eating droseroflugia, settled in the traps of pitcher-leaved sundew on outskirts of the Mediterranean basin, and adapted to make shelter from particles of the plant’s prey. This is almost the sole habitable place for relics of freshwater microbiota after aridization of this terrain.
This amoeba is the same size as drosarcella – about 0.2 mm. Inhabiting the trap leaves of the sundew and ingesting microparticles of its prey, droseroflugia excretes solid undigested particles onto its surface and agglutinates with an organic matrix. Therefore, the outer appearance of its test is variable and depends on the sundew’s prey. But generally the test consists of solid particles obtained from insects captured by the sundew: microscopic parts of their shells, antennae, legs, wings etc. All this creates a variegated spotted shell on the amoeba, and it protects the protozoan from the sun. The test is bell-shaped with a wide aperture in the bottom, from which the amoeba’s pseudopodia protrude.
The life style of this species is the same as in drosarcella, but it is commonly found on the surface of the liquid in the traps, or creeping on partly submerged prey.
Droseroflugia multiplies by division with the same mechanism as in drosarcella. In adverse conditions, this species forms cysts that are spread by insects.

This species of protists was discovered by Biolog, the forum member.
Translated by Biolog.

“Spelean sulfur” (Sulfophysarum spelaeus)
Order: Fuscisporida (Fuscisporida)
Family: Physaridae (Physaridae)
Habitat: caves of North America (the Appalachians).

Picture by Biolog

The slime molds (myxomycetes) are a quite widespread group of holocenic fungoid organisms inhabiting moist places in temperate forests of all continents. They play an important role as decomposers of organic remains and regulators of bacterial populations. Some of their descendants in Neocene mastered new ecological niches, and one species has relocated to caves, having adapted to specific life conditions.
“Spelean sulfur” is a descendant of Physarum genus which had lived mainly on dead wood. The plasmodium of this species appears as a thin and soft pale yellow moist crust permeated with a dendriform network of growth tubules. It is a single large multinucleated cell that is the vegetative stage of the organism. The plasmodium can move slowly (about 5 cm per hour), and simultaneously grow from the edges. During sporulation, the plasmodium stops moving and covers with a tough coat. Sporangia of the same color, about 1 cm in diameter on small stipes, appear on it. They are covered with cellulose coat and open from the base. Colorless spores also have cellulose coats, and are spread (and partly eaten) by cave insects and mites. Myxamoebas – amoeboid gametes – emerge from spores that found favorable conditions with proper moisture and temperature. Fusing in pairs, they give rise to new plasmodia.
This slime mold feeds on guano and organic remains of animals (birds and mammals) inhabiting the cave, and also on bacteria, which multiply in large numbers on these substrates. Feeding on bacteria, the plasmodium can creep on stone walls and even the arch of the cave; in both cases, the sporangia will hang down. Spores also can spawn new myxamoebas and new plasmodia on the walls and ceiling of the cave.
Insects that spread the spores of “spelean sulfur” are guided by light: the myxomycete gives off a yellowish glow, dim but clearly seen in the dark, and the cave brightens up with yellow stains, resembling deposits of native sulfur (hence the species’ name).

This species of slime molds was discovered by Biolog, the forum member.
Translated by Biolog.

Retaria

Corallogerina (Corallogerina natans)
Order: Globigerinida (Globigerinida)
Family: Globigerinidae (Globigerinidae)
Habitat: seas of warm and temperate climate around the globe.

Picture by Biolog

In prehistoric and human eras, foraminifera held a special place among the marine protozoans, playing an immense role in geological processes. Their calcareous shells formed bottom sediments – the limestone and chalk. The thickness of these deposits reached dozens and hundreds of meters, and sometimes even kilometers. In Neocene, this geological process continues, although the species composition of its participants has changed significantly.
Corallogerina is one of typical foraminifera of Neocene, a descendant of Globigerina genus of human era. It inhabits warm and temperate seas at shallow depths (up to several meters) as a part of marine plankton. Their ancestors, globigerinas, were also planktonic foraminifera, their tests were thin and translucent, and extremely thin (like a spiderweb) pseudopodia protruded through the pores.
Corallogerina has inherited all of its ancestor’s traits, but the nuclei of agamont (diploid generation) in it divide repeatedly and give rise to an aggregate of cells, which do not secede and stay together. These cells cover with tests, and the colony resembles pieces of coral branches (hence the species name) soaring in the water column. The diameter of one cell in the test is small (2-3 mm), but the branching colony reaches 2-3 cm in length and consists of 10-15 haploid cells.
Each of these cells can then spawn gametes, and the gametes, by fusing, produce a zygote, which gives rise to a new agamont generation, thus continuing the life cycle.
The tests in corallogerina are thin, spherical, almost transparent, bearing small spikes on the outer surface, and pores through which extremely thin pseudopodia protrude and surround the cell with an arachnoid halo.
The tests of corallogerina compose a significant part (half and more) of bottom calcareous sediments of neocenic seas, forming very thick deposits of lime ooze, up to 4-5 meters thick.

This species of protists was discovered by Biolog, the forum member.
Translated by Biolog.

Golden heliochromococcus (Heliochromococcus aureus)
Order: Arthracanthida (Arthracanthida)
Family: Heliochromococcidae (Heliochromococcidae)
Habitat: tropical seas around the globe.
Starting from early Paleozoic, one group of marine planktonic protozoans had mastered the construction of skeletons mainly from silica (SiO₂) and entered into symbiosis with algae to obtain energy of sunlight. These are radiolaria – very peculiar and beautiful marine microorganisms. In Neocene, one of the groups of these organisms began to evolve towards total autotrophy.
Heliochromococci are spherical radiolaria of Acantharia group inhabiting surface (up to several meters) layers of water in warm tropical seas of Neocene. Just like their ancestors, they synthesize skeletons from strontium sulfate (SrSO₄, celestine). These are small pelagic organisms about 0.5-1 mm in diameter. Their skeleton appears as two cribriform spheres nested in each other and connected by beams. Both spheres are transparent like glass, and shine in the sun. The radius of the inner sphere is ½ of that of the outer sphere, and it is entirely occupied with a large central capsule filled with golden-yellow zooxanthellae. Ectoplasm is between two spheres, and also covers the outer sphere from outside. Numerous pseudopodia, extremely thin like spiderweb, stretch out of it. The outer surface of the outer sphere is smooth, but bears 20 thin straight spikes arranged in a regular icosahedral pattern. The sphere’s walls between the spikes bear thickenings arranged checkerwise and performing the role of optical lenses to provide zooxanthellae with light.
Zooxanthellae have undergone assimilation in the cells of heliochromococci and lost the ability to live independently. And the radiolarian, due to this, switched to full autotrophy – it provides the zooxanthellae with mineral substances from the water, and they provide it with organic substances and energy by photosynthesis.
The life cycle in heliochromococci is the same as in their ancestors: a fully formed organism produces flagellated zoospores, which lose flagella and produce their own skeletons to give rise to a new organism. During zoospore formation, a part of zooxanthellae passes to the spore and then to the new organism.
In favorable conditions, heliochromococci can multiply in large numbers, causing a golden sea bloom.
Blue-green heliochromococcus (Heliochromococcus cyaneus) is a species with green zoochlorellae, its spikes are thickened at the ends and have a bluish tint (the color of strontium sulfate). This species causes a bluish-green sea bloom.
Red heliochromococcus (Heliochromococcus ruber) contains reddish-orange zooxanthellae and has thin spikes branched at the ends, and causes orange-red sea bloom.

This species of protists was discovered by Biolog, the forum member.
Translated by Biolog.

Azure vanadella (Vanadella azurea)
Order: Vanadellata (Vanadellata)
Family: Vanadelloideae (Vanadelloideae)
Habitat: tropical seas around the globe, near-surface and middle layers of water (up to dozens of meters deep).
Radiolaria (phylum or subphylum Radiozoa) in holocene were well-known for their ability to form cytoskeletons from silica (SiO₂), and one group from strontium sulfate (SrSO₄). However, the sea water contains many compounds of other elements, and one of the main places is held by vanadium which is present there as the vanadyl ion (VO²⁺). Vanadium is toxic as pure oxides, but as vanadyl it was used by some marine organisms of holocene. These organisms learned to include vanadium in cofactors of enzymes (some algae and bacteria) and in protein molecules with further accumulation in special cells (tunicates, particularly sea squirts – as a way of protection against predators). By the Neocene time, some radiolarians also switched to using vanadium compounds to produce their cytoskeletons.
Vanadellas (Vanadellae) are a new class of neocenic radiolarians. Their main distinctive feature is the cytoskeletons made of complex silicates with vanadium and calcium (such composition is inherent for vanadium minerals cavansite and pentagonite). These skeletons consist of intersecting ring structures with common intersection points on the skeleton’s “poles”. Tufts of rather long needles go from these points, and both rings and needles can be smooth or spiked. The entire skeleton is stained a color with various tints depending on the vanadium content: azure, sapphire, saturated blue of various tints.
The central capsule in vanadellas is not separated from the ectoplasm: their cells do not contain zooxanthellae, they are totally heterotrophic. This allows them to inhabit greater depths than their relatives, who depend on the symbionts’ photosynthesis. The life cycle in vanadellas does not differ from that of their ancestors and relatives. Vanadellas feed on bacteria and organic particles suspended in the water.
In the azure vanadella, the cells are 0.2-0.4 mm large, have 5 rings and 5 needles in the skeleton, which is covered with small spikes and entirely stained bright-blue.
By converting vanadium, vanadellas take part in its mineralization, enriching the bottom sediments with it. Multiplying in large numbers, vanadellas cause water bloom, giving it a color corresponding the color of the vanadella’s skeleton.
Turquoise vanadella (Vanadella caerulea) has 7 smooth rings and needles stained bright blue with a turquoise tint. It inhabits greater depths of water than the azure vanadella (30-40 m).
Purple vanadella (Vanadella purpurea) has 6 rings and needles covered with spikes and stained purple-blue. It inhabits subsurface layers of the water (first few meters).

This species of protists was discovered by Biolog, the forum member.
Translated by Biolog.

Bacteria

Philanthomycete (Philanthomyces antibioticus)
Order: Actinomycetales (Actinomycetales)
Family: Streptomycetaceae (Streptomycetaceae)
Habitat: Fennoscandian forests, a symbiont in burrows of hymenopterans
Streptomycetes (Streptomyces genus) were one of main tools for humans to control infectious diseases – humans obtained dozens of antibiotics of various action spectrum. These filamentous bacteria produced erythromycin, tetracyclines, levomycetin, nystatin, amphotericins, neomycin, vancomycin, and many other antibiotics, and also other important substances (tacrolimus, allosamidin and other). Representatives of streptomycetes entered into symbiosis with insects – they lived in pockets of antennae of female beewolf (Philanthus triangulum) and protected its eggs and larvae from soil mycelial fungi. In Neocene, this symbiosis got further development, and the relationships between the actinomycete and the insect became even stronger. A new actinomycete – philanthomycete – emerged in the process of their joint evolution.
Philanthomycete is a typical representative of actinomycetes. Its cells appear as thin branching aseptate filaments which divide into thinner substrate filaments and thicker aerial filaments. The aerial filaments form dense tufts with chains of thick-walled spores formed on their ends by successive fragmentation. The filaments and spores are hyaline, filaments up to 1.3 μm thick.
This species is a symbiont of a crabronid wasp named beelynx (Neophilanthus apilynx). The actinomycete is present as spores in the antennal pockets of female wasps. The spores germinate quickly on the walls of burrow chambers and on the prey – paralyzed bees. The actinomycete forms a thin white powdery coating there. A wasp hatching from the pupa touches the coating with antennae to gather spores into the mycangia.
The main help for the wasp from the bacterium is protection: the bacterium has inherited the ability to produce antibiotics from its ancestors. Philanthomycete produces large amounts of philanthomycin – a nystatin derivative which is a potent antifungal antibiotic with a broad action spectrum. Philanthomycin prevents the growth of any fungi inside the insect’s burrow, thereby protecting the larva and its forage from being destroyed. After eating a prey with the bacterial coating, the wasp’s larvae become resistant to fungal infections, including Entomophthorales and Cordyceps that are specialized insect parasites. In exchange, the bacterium receives nutrition – parts of the wasp’s prey and excrements and secretions of the larva.
The ancestors of this species were less specialized and inhabited a broader spectrum of niches – soil, surface of plants, organic-polluted water etc. But philanthomycete, due to the close symbiotic relationships, is no longer found outside the wasp’s burrows.

This species of bacteria was discovered by Biolog, the forum member.
Translated by Biolog.

Infectiofly asporoclostridium (Asporoclostridium dolichomusci)
Order: Clostridiales (Clostridiales)
Family: Clostridiaceae (Clostridiaceae)
Habitat: tropics and subtropics of the Old World – Africa, Zinj Land, Asia and southern Europe.

Picture by Biolog

In human era, clostridia were very abundant group of anaerobic soil bacteria, although some species inhabited (permanently or temporarily) human and animal intestine. Some species were deadly dangerous for humans due to very potent exotoxins, e. g. agents of botulism (Clostridium botulinum), tetanus (C. tetani) and gas gangrene (C. perfringens and similar species). In Neocene, some clostridia have taken a new evolutionary step: they have lost the ability to produce spores because of favorable conditions they found after entering into symbiosis with dipteran insects.
Asporoclostridium dolichomusci is a descendant of C. perfringens. It is a large (3-4 μm long and 2 μm thick) gram-positive, obligately anaerobic rod, inhabiting pockets of digestive tract of some carnivorous flies (particularly, infectioflies and sambios). This bacterium is a chemoorganotroph, and inside the insect’s organism it uses the host’s food for nutrition, without harming the fly. But when it enters the body of a living vertebrate animal, the picture changes dramatically. The bacterium produces a potent exotoxin (neurotoxin), which acts like the botulism toxin of C. botulinum and tetanospasmin of C. tetani, and also some hemolytic enzymes. This complex quickly (without “aid” of other bacteria in 2-3 days) kills the animal since the fly injects this “biological weapon” with its proboscis directly into the tissues and bloodstream of the victim, causing an instant sepsis.
When the fly shows up to “have lunch”, it sucks in a new portion of bacteria (which have multiplied in the victim’s body) with food. In fact, the symbiotic bacteria circulate between the fly and its victims, almost totally avoiding getting into the environment, which allowed them to do without endospores. Besides clostridia, this deadly microbiome of flies includes fly escherichia (a descendant of E. coli – a former inhabitant of animal intestines, including insects) and sambio fly staphylococcus (a descendant of S. aureus – a former member of human and animal normal microbiota).

This species of bacteria was discovered by Biolog, the forum member.
Translated by Biolog.

Sambio fly staphylococcus (Staphylococcus sambiorum)
Order: Bacillales (Bacillales)
Family: Staphylococcaceae (Staphylococcaceae)
Habitat: tropics and subtropics of the Old World – Africa, Zinj Land, Asia and southern Europe.

Picture by Biolog

Staphylococci – gram-positive cocci in bunches – were common inhabitants of human and animal organism in holocene. They also included very dangerous forms, e. g. Staphylococcus aureus. A descendant of this species entered into symbiosis with carnivorous dipteran insects and began to play an important role in their life.
Staphylococcus sambiorum inhabits the pockets of digestive tract of sambio and infectioflies, feeding on the insect’s food without harming it. When the fly bites a victim (a vertebrate animal), the bacterium enters the animal’s tissues and bloodstream and multiplies quickly, and simultaneously produces its main “weapon” – coagulase. This enzyme in this species possesses a very high activity and causes a very quick clotting of the animal’s blood directly in the blood vessels. This is a fatal process, resulting in a rather quick death of the victim. When the fly starts feeding on the carcass, the bacteria are sucked in through the proboscis, and the fly’s “biological weapon” is “reloaded”. The fly’s larvae receive the bacteria with food.
Morphologically, this species does not differ from its ancestors: it is a gram-positive coccus forming bunches. It is a facultative anaerobe, resistant to high concentrations of salt. A chemoorganotroph, a mesophile, resistant to immune responses of animals. Besides coagulase, S. sambiorum produces potent leukocidins (toxins that kill leukocytes) to protect itself from the immune system of the insect’s victim, and at the same time to help its neighbours – fly escherichia and clostridia.

This species of bacteria was discovered by Biolog, the forum member.
Translated by Biolog.

Pitcherplant-leaved sundew leguminobacter (Leguminobacter neodroserae)
Order: Rhizobiales (Rhizobiales)
Family: Rhizobiaceae (Rhizobiaceae)
Habitat: outskirts of the Mediterranean basin.

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Picture by Biolog

In Holocene, some soil bacteria capable of fixing atmospheric nitrogen did this in a peculiar and interesting way. The nitrogen fixers of Rhizobium genus formed nodules on plant roots (mainly of leguminous plants). In the nodules they, being provided with required nutrition and protection from oxygen (since nitrogen fixation is an anaerobic process) by the plant, in exchange provided the plant with fixed nitrogen in a metabolizable form. But rhizobia could also live freely in the soil, contributing to the soil part of nitrogen cycle, and underwent deep changes (formation of bacteroids) when entering into a plant root. In Neocene, their descendants have kept and modified this ability, and have continued the symbiotic relationships with plants.
Leguminobacters differ from their ancestors in that they live only inside the tissues of plants, leguminous and some other families. And each plant species has its own species of bacteria, isolated from others. Morphologically, it is all the same gram-negative bacteroids, and they are still capable of fixing atmospheric nitrogen anaerobically in the nodules. Their distinctive feature is that they mastered colonization of the plant’s vascular bundles and get to the ovules by them, and from there – to the embryos in seeds. During vegetative reproduction, they just pass into a new rooting plant. These are the ways they are transmitted to new host plants. This close union allowed such plants to settle in unsuitable, nitrogen-poor soils, but in some cases the bacteria form nodules only when the plant is short of nitrogen, the plant in this case sends a chemical signal to its symbionts.
The system of nitrogen fixation in leguminobacteria remained the same, but they began to form larger nodules (the size of a pea and larger) not only on roots, but also on other parts of the plant: on the stem and even on the leaves. The tissues of stems and leaves with this do not lose their photosynthetic function (the outer layers of the tissues of such nodule remain green). The nodules have internal partitions (compartments) that contribute to more uniform distribution of the bacterial mass and enlarge the area of absorbtion of the fixed nitrogen by the plant. The pulp of the nodules is stained pink and even red by leghemoglobin. Leguminobacteria have a defective metabolic system, and therefore they cannot live outside the host plant: if the plant itself is destroyed or a nodule is damaged, the bacteria quickly stop fixing the nitrogen and die.
The bacteroids of leguminobacteria are very small (about 0.1-0.2 μm) polymorphic cells with a single, partly incomplete murein layer in the cell wall. They are organoheterotrophs by the life style, totally dependent on the host plant. They are aerotolerant: they can live in the presence of oxygen, but the nitrogen fixation occurs only in anaerobic conditions. They do not form capsules and spores.

This species of bacteria was discovered by Biolog, the forum member.
Translated by Biolog.

Fly escherichia (Escherichia muscina)
Order: Enterobacteriales (Enterobacteriales)
Family: Enterobacteriaceae (Enterobacteriaceae)
Habitat: tropics and subtropics of the Old World – Africa, Zinj Land, Asia and southern Europe.

Picture by Biolog

In human era, enterobacteria were one of the most numerous and abundant groups of bacteria. Their members inhabited all available niches – water, soil, and animal (including invertebrates) and human organisms. Escherichia genus was the most common among all intestinal bacteria, partly very important intestinal symbionts and partly dangerous pathogens causing infections (toxigenic strains). Their descendants in Neocene only weakly changed in general, but some have switched to another life style, taking advantage of the rapid evolution of fauna in the period of ecosystem recovery.
Escherichia muscina is the same gram-negative facultatively anaerobic rod, motile by means of peritrichous flagella, a chemoorganotroph. But it inhabits a new medium – the pockets of digestive tract of robberflies (infectioflies and sambio). Having entered into an animal’s body with the fly’s sting, it multiplies quickly and produces a set of potent toxins, the main role belonging to hemolysins. Being produced in large amounts, they cause a fulminant lysis of red blood cells and hemoglobin in the animal blood, which is fatal to the animal. Along with them, the animal is affected by the clostridial neurotoxins and staphylococcal coagulase. This species hardly produces endotoxins, the cells just do not have time to be disrupted to discharge the exotoxins – the affected animal dies too quickly.
E. muscina, like clostridia and staphylococci, multiplies quickly in the doomed animal’s body, and the fly gets a chance to “reload” its “biological weapon”. And the fly’s larvae, feeding on the carcass, acquire their own microbiome of deadly symbionts.

 

Infusorial photobacterium (Photobacterium endoprotistum)
Order: “Vibrionales” (“Vibrionales”)
Family: Vibrionaceae (Vibrionaceae)
Habitat: all oceans of the globe, bathyal zone.

Picture by Biolog

Photobacteria, known in human era, had a peculiar feature that allowed them to develop a specific “quorum sensing” – they were able to glow. The luciferin-luciferase system allowed them to emit bluish light upon forming cell aggregates. Their descendants in Neocene have kept this ability, but switched to another life style.
Photobacterium endoprotistum is a medium-sized (1-1.5 μm) rod-shaped bacterium with rounded ends, one of which bears a single polar flagellum. This species is still gram-negative by the structure of the cell wall, but the cell is covered with a slimy capsule from outside. The species is a chemoorganotroph, and does not form spores. It is a facultative anaerobe, a psychrophile, and a moderate barophile by the requirements to the medium it lives in. It finds favorable conditions in the deep of the oceans.
These bacteria can live both in the water and inside the cells of a parasitic ciliate photopiscidium (Photopiscidium bathichthybolis), which swallows them during the stage of a young swarmer. Inside the cell, the bacteria are protected against the ciliate’s digestive enzymes by capsules. They lose flagella and feed from the ciliate while it parasitizes on a fish body.
Accumulating in the ciliate’s cytoplasm, they start glowing (quorum reactions turns on). As the ciliate passes along the fish organism to the sites of final settling, the bacteria partly die and the luminescence weakens, but newly released swarmers replenish the losses. Also, the bacterial number increases at the expense of the nutrients from the ciliate’s cell.

This species of bacteria was discovered by Biolog, the forum member.
Translated by Biolog.

Volvox-like nostoc (Nostoc volvoxoides)
Order: Nostocales (Nostocales)
Family: Nostocaceae (Nostocaceae)
Habitat: still freshwaters of temperate climate in the Northern Hemisphere.

Picture by Biolog

Cyanobacteria have been the largest and the most important group of photosynthesizing autotrophic prokaryotes during the whole history of the Earth. They inhabited fresh and saline water bodies and the soil. Some species entered into symbiosis with fungi as part of lichens, and even with flowering plants, in the latter case the plant gets required nitrogen since cyanobacteria can fix atmospheric nitrogen.
Members of Nostoc genus were common in fresh water bodies and in moist soils where they formed spherical jelly-like colonies. Some of their descendants in Neocene have switched to another life style.
Nostoc volvoxoides has kept the cellular morphology of its ancestors. Its cells, with a membrane system (thylakoids) bearing photosynthetic pigments, instead of chains form dense single-layer mats closed into hollow balls the size of a pea, covered with a gelatinous capsule. Large heterocysts (specialized cells that fix atmospheric nitrogen) inherited from ancestors stand out among the ball’s cells. Also, the species has large floater cells with gas bubbles in the cytoplasm, which allow it to soar in the subsurface water layers (and even to surface up and protrude from the water) where the colony gets maximum light and nitrogen.
The balls are stained usually blue-green; pale yellowish spherical heterocysts and almost hyaline “gas” cells stand out on them; both heterocysts and “gas” cells are 1.5-2 times larger than usual cells.
The cells of N. volvoxoides reproduce by fission, and daughter cells are deposited inside the ball, while mother cells die gradually. Thus, 2-3 daughter colonies form inside the ball, they are released via rupture of the mother colony as it dies.
In favorable conditions, N. volvoxoides multiplies in large numbers and causes blue-green water bloom. Living and dead colonies in this can stick together to form carpets (mats) on the water surface. The carpets reach 1-2 meters large and are so solid that insects and other small animals walk or crawl freely on them. Small numbers of this “alga” are consumed by herbivorous fish and also by land herbivorous mammals.

This species of bacteria was discovered by Biolog, the forum member.
Translated by Biolog.

Symbiotic anabaena (Anabaena schizolemnae)
Order: Nostocales (Nostocales)
Family: Nostocaceae (Nostocaceae)
Habitat: fresh waters of the North Hemisphere in cold climate zones, a symbiont of Schizolemna anabaenophila

Picture by Biolog

During the whole history of life on the Earth, cyanobacteria repeatedly entered into symbiosis with various plants. Receiving “shelter” from the plant, they provided it with nitrogen which they fixed from the environment. Some species of such symbionts, particularly of Anabaena genus, inhabited tissues of aquatic plants, e. g. Azolla fern and angiosperms duckweeds (Lemna). Their descendants in Neocene have evolved and changed according to the changes in the structure and life style of their hosts – the duckweeds.
Anabaena schizolemnae has undergone significant morphological changes. It has two morphologically different stages: a free stage living in water and a symbiotic stage living in the tissues of Schizolemna, a duckweed.
The free-living stage appears as long filaments composed of green barrel-shaped cells, alternating with large spherical yellowish heterocysts – this appearance is characteristic of ancestral and related forms. And the symbiotic stage appears as a heterocyst about 10 μm in diameter with two blue-green photosynthetic vegetative cells on the sides. These cells are 1.5 times smaller than the heterocyst, and provide its development. Such structure allows A. schizolemnae to provide the plant with nitrogen (fixed by heterocysts) at a maximum efficiency with keeping its own photosynthesis. A large number of such three-cell symbionts accumulates in the duckweed’s tissues, and the compactness allows to distribute more uniformly, giving the Schizolemna’s symbiotic tissues a brownish-green color. During vegetative reproduction of the host plant by fission of the leaflet, the symbiont’s cells distribute in it equally enough. In the Schizolemna’s growth process, the vegetative cells of A. schizolemnae divide to form new undifferentiated cells outside of the heterocyst. When their number in a chain reaches three, they secede and differentiate into a heterocyst and vegetative cells. Undifferentiated cells of A. schizolemnae penetrate even the ovules of the duckweed, and in rare cases of seed reproduction of the host plant, the seedlings already bear the symbiont in their tissues. In the fall, the duckweed plants stop the photosynthesis, accumulate starch and submerge into the water to winter there. In these conditions, A. schizolemnae forms spores that can winter in the duckweed’s tissues.
The free stage forms only when the symbionts for any reason fall out of the duckweed’s leaflet into the water. They cannot enter the organism of the same or another duckweed again, but instead they divide to restore filamentous structure, and live independently. Since such situation is quite rare, A. schizolemnae is almost absent in water blooms.

This species of bacteria was discovered by Biolog, the forum member.
Translated by Biolog.

“Blood-of-the-salt” halobacterium (Halobacterium sanguinisalis)
Order: Halobacteriales (Halobacteriales)
Family: Halobacteriaceae (Halobacteriaceae)
Habitat: hypersaline wetlands of Mediterranean basin, in water and on salt deposits.

Picture by Biolog

In human era, Archaea inhabited various niches with extreme conditions, mainly elevated temperature, very high acidity, or salt concentrations at a level of strong brine. They possess such abilities due to biochemical differences from bacteria and eukaryotes: cell walls in most of them lack murein and consist of highly resistant proteins, and the membrane lipids have a unique structure, also with high resistance. Their descendants in Neocene have kept most of the ancestral features, and this helped them to master new niches.
Halobacterium sanguinisalis inhabits the world of salt in the Mediterranean basin. It has inherited the ability of bacteriorhodopsin-mediated photosynthesis from its ancestors, whose cells were stained red by bacteriorhodopsin. With this, it does not assimilate carbon, but obtains it from other sources. Like its ancestors, H. sanguinisalis accumulates sodium and potassium salts inside the cell (crystals in the cytoplasm) to resist the osmotic drain of water from the cell to the environment. But the life under scorching sun has resulted in emergence of a new adaptation – accumulation of additional pigments that protect the cell from excess solar UV. These pigments give the rhomboid cells of this species a dark red-purple color resembling human venous blood – hence its name. The rhomboid cells are 8-10 μm large, flat and very thin, they adjoin each other like an argyle pattern and stick together, forming plates of 10-20 cells (up to 100 μm large). The edge cells bear archaella – transformed archaeal flagella. The whole plate can swim freely by using them.
Breeding in large numbers, these organisms cause a dark-red color with a purple tint of brine, and also of salt formations and crystals where enough moisture is present on them for the microorganisms to develop.
H. sanguinisalis participates in the phosphorus cycle, converting its compounds, and also enters into symbiosis with a filamentous alga Filodunaliella mediterranea, from which the archaeon gets carbon as glycerol. The filaments of F. mediterranea often cling to the plates of the halobacterium and float in the brine together with them.

This species of archaea was discovered by Biolog, the forum member.
Translated by Biolog.

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