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Translator's shelter (ïðîäîëæåíèå)
Ñåì¸í: Òî áèøü "Ïðèþò Ïåðåâîä÷èêà". Òåìà äëÿ îáñóæäåíèÿ ïåðåâîäîâ: 1) Ïðîåêòà "Íåîöåí" íà èíîñòðàííûå (îò àíãëèéñêîãî è íåìåöêîãî äî ìîíãîëüñêîãî è êâýíüè) ÿçûêè. 2) Èíîñòðàííûõ ïðîåêòîâ è êíèã ñîîòâåòñòâåííî íà ðóññêèé. 3) Îáîãàùåíèå ëåêñèêîíà ñî÷íûìè èñïàíñêèìè ðóãàòåëüñòâàìè è ïðî÷. Âñåõ Ìèõàèëîâ Ëîçèíñêèõ è Äàíèýëåé Øòàéíîâ îò áèîëîãèè ëàñêàâî ïðîñèìî.
Áèîëîã: And another one: Bathytrichodine (Bathytrichodina parasitivora) Order Mobilida Family Trichodinidae Habitat: all oceans of the Earth, bathyal zone. Trichodines were specialized ciliates of holocene, inhabiting bodies and gills of fish. Their body was flattened-convex, usually in the shape of a thick one-sidely convex lens. The bottom surface of such lens, adjoining to the fish’s body, had an attachment sucker disk with a concave center and a ring of of radial cytoskeletal denticles. The cytostome (cellular mouth) was on the top, surrounded by a ring of cilia. In neocene, the bathytrichodine, inhabiting the bodies of deepsea fish, has kept these features. Its cell, about 0.7-0.8 mm in diameter, has the same lens-shaped appearance. The attachment disk has 30 denticles, diverging from the center, and is surrounded with a ring of cilia. The upper ring around the cytostome consists of long, slightly thickened cilia. The ciliate creeps freely across the fish’s body by means of movement of the cilia of the lower ring, but it also can detach to swim freely – usually this happens when the host dies. But the fish’s body gives it a plentiful treat – it can catch swarmers of photopiscidium (Photopiscidium bathichthybolis) and digest them. Moreover, the ciliate does this including during rupture of a mature cyst of the parasite on the fish’s skin. Bathytrichodines can sense the presence of the cysts by their luminescence (the ciliate rods often survive in new swarmers) and creep closer to them, thus demonstrating positive phototaxis. Unlike its ancestors, which were partial parasites of fish, bathytrichodine helps the fish get rid of parasites in exchange for food. Bathytrichodine reproduces by simple division, like its ancestors: the fission occurs parallel to the sucker disk, and the new cell grows cilia and a new sucker disk to swim away and settle in a new place, more precisely, on a fish body. Usually, such swarming ciliates soar motionless in the water column and are activated only at the emergence and subsequent enhancement of odor of a possible host.
Áèîëîã: Here's another: Photopiscidium (Photopiscidium bathichthybolis) Order: insertae sedis Family: insertae sedis Habitat: all oceans of the Earth, bathyal zone. One of marine holocenic ciliates – Cryptocaryon from Prostomatea class – had adapted to parasitize on fish, causing a disease named cryptocaryonosis (“marine ichthyophthiriosis”). This parasite formed cysts in the fish’s skin, with new swarmers forming inside them. Some descendants of this species changed their life style in neocene. Photopiscidium lives in deep waters of oceans and parasitizes on deepwater fish. A mature swarmer appears as an oval or ovoid cell about 0.5 mm in diameter, covered with cilia, with a bean-shaped macronucleus and a small micronucleus. It glows from inside with a bluish light – its cytoplasm contains symbiotic bacteria ciliate rods (Photobacterium endoprotistum) as several aggregations. Bacteria receive food (which is hard to find in the deep of the ocean) from the ciliate in exchange for help in infecting fish. Glowing ciliates soar in the water column and attract young and small fish, which eat them. Inside the fish’s intestine, the ciliate produces potent enzymes to pierce through the intestinal wall, get into the bloodstream and settle in the host’s skin, along the way consuming the fish’s body substances and feeding them to their symbiotic bacteria. At this stage of invasion, part of the bacteria sometimes dies from the ciliate’s enzymes. In the fish’s skin, photopiscidium forms cysts, the cell repeatedly divides inside it. The cyst grows up to 1.5-2 mm with this, and glows with intensity depending on the number of ciliate rods that have survived in the new cells. In favorable conitions, the bacterial population restores rapidly. Over time, the cyst ruptures, and a new portion (several dozens) of new swarmers comes out. In the water, they feed freely for some time, swallowing new living ciliate rods, and then, once they acquire sufficiently bright glowing, they are swallowed by a fish. Dozens of such cysts can appear on one fish, and it gleams like the night starry sky. Such gleaming attracts other fish that feed by predation, and photopiscidium gets a chance to enter another victim’s body even without leaving the previous one. But this rarely happens at great depths. Fish have their own protection from this parasite – dangers await the swarmers before they infect and just before they exit from the cysts: sucking infusoria ichthyocinetes (Ichthyocineta symbiotica) and creeping ciliates bathytrichodines (Bathytrichodina parasitivora) inhabit the fish skin, and they often feed on the photopiscidium’s swarmers.
Áèîëîã: Proceeding again... Iridescent noctiluca (Multiluca versicolor) Order Noctilucales Family Noctilucaceae Habitat: tropical and moderately warm seas worldwide. In the human era, some marine flagellates had adapted to repel enemies by bright light flashes of bioluminescence. The organisms of this kind in human era were the noctiluci (Noctiluca), which used to flare brightly when disturbed. Forming large aggregations, they caused sea mareel (or milky sea) on large areas. Their descendants in warm and temperate seas of neocene have kept many of their features, but the evolution of some of them took new directions. The iridescent noctiluca became one of such species. This species became colonial from solitary: dividing cells, 3-4 mm in diameter, do not come apart and form laminar coenobia resembling those in a holocenic alga Gonium. The coenobia in the iridescent noctiluca are 15-16 mm wide and consist of 8-32 identical cells enclosed in a collective slimy capsule. The iridescent noctiluca has inherited the cellular structure from its ancestors: it has a cellular mouth and a modified contractile flagellum tentacle, and also fat inclusions in the cytoplasm, which allow the cells to soar in the water column. When a coenobium is disturbed, all of its cells flare up brightly, simultaneously then separately, and the bioluminescence color can be different in different cells within one coenobium, and with this the colony shimmers with reddish, yellowish, bluish and greenish light. Such illumination will repel almost any dinoflagellate hunter. The ways of reproduction in the iridescent noctiluca are the same that in its ancestors, but adjusted for colonial life style: either the coenobium breaks into separate cells and they give rise to new colonies, or the cells bud within the coenobium. Both ways occur equally often and alternate with each other. In favorable conditions, iridescent noctiluci multiply in great numbers and cause a bright shimmering mareel which gleams with all colors of the spectrum.
Áèîëîã: Fixed some typos in the text above. Will proceed with another one soon.
Áèîëîã: Another one is done: Sundew bodonid (Endobodo droserae) Order Bodonida Family Bodonidae Habitat: outskirts of the Mediterranean basin. Bodonids were one of the most widespread groups of flagellates in small or even temporary, polluted freshwater ponds of holocene. They were abundant in puddles, ponds and wetlands, but preferred places where bacteria – their main food – multiply. One of its descendants – the sundew bodonid – inhabits the pitcher-like traps of the pitcher-leaved sundew (Neodrosera nepenthifolia), which grows in arid conditions of outskirts of Mediterranean basin. These are very small (no more than 50 μm) flagellates – their habitats are too small in volume. The cells are ovoid, bearing two flagella (anterior and posterior) on the wider end. The flagella have large basal bodies, and a cytostome (cell mouth) is located in the bottom of the flagellar pocket. The entire surface of the cell is strengthened with microtubules that underlay the cellular membrane – this allows to maintain a constant cell shape and to move in a viscous medium. The posterior flagellum is shortened (three times shorter than the anterior one) and bears the function of driving bacteria and other food into the cytostome. The cell often has several (up to 5-6) digestive vacuoles filled with food and appearing dark, almost black. In arid conditions of Mediterranean basin, this species has found a habitat and a food source in the trap leaves of the sundew, where some moisture remains. Prey caught by the sundew and partly digested always can be found there, and this prey becomes a substrate for bacteria, and the bacteria, in turn, are food for the sundew bodonid. This species is a commensal that eats from the sundew’s table, although it partially performs a cleaning function: it prevents spoilage of the sundew’s digestive fluid by eating bacteria. The cell wall of this species is more durable than in its ancestor, so that it can withstand the digestive action of the fluid in the sundew’s leaves. In adverse conditions, the flagellate can form cysts, in which it keeps viable for a long time (up to several weeks). Usually, this happens when the aerial part of the plant dries due to lack of moisture. The cysts are easily carried by the wind and driven into the traps of other sundews. Also, the are easily transmitted on the feet of insects that managed to escape from the plant’s traps.
Áèîëîã: Another one... Glassy drosarcella (Drosarcella vitrea) Order Arcellinida Family 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 glassy 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.
Áèîëîã: Another one... Insectivorous droseroflugia (Droseroflugia insectivora) Order Arcellinida Family 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 insectivorous 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.
Áèîëîã: And a slime mold: “Spelean sulfur” (Sulfophysarum spelaeus) Order Fuscisporida Family Physaridae Habitat: caves of North America (the Appalachians). 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, a forum member
Áèîëîã: Here's the foraminifera: Corallogerina (Corallogerina natans) Order Globigerinida Family Globigerinidae Habitat: seas of warm and temperate climate around the globe. 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.
Áèîëîã: Replaced "silt" with "ooze" in the text above. Another one coming soon.
Áèîëîã: Here are heliochromococci: Golden heliochromococcus (Heliochromococcus aureus) Order Arthracanthida Family 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.
Áèîëîã: And here's the final protozoan species! Now for bacteria! Azure vanadella (Vanadella azurea) Order Vanadellata Family: 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). Oh, and I will also translate my plants (sundew and filodunaliella) and one animal (beelynx).
Áèîëîã: Replaced "although" with "however" in the text above. The first bacterium coming soon!
Áèîëîã: Bacteria are here now! Philanthomycete (Philanthomyces antibioticus) Order Actinomycetales Family 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.
Áèîëîã: And a clostridium is done: Asporoclostridium dolichomusci Order Clostridiales Family Clostridiaceae Habitat: tropics and subtropics of the Old World – Africa, Zinj Land, Asia and southern Europe. 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 the muscine rod (a descendant of E. coli – a former inhabitant of animal intestines, including insects) and sambio staphylococcus (a descendant of S. aureus – a former member of human and animal normal microbiota).
Áèîëîã: Staphs are here! Staphylococcus sambiorum Order Bacillales Family Staphylococcaceae Habitat: tropics and subtropics of the Old World – Africa, Zinj Land, Asia and southern Europe. 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 – the muscine rod and clostridia.
Áèîëîã: Another one... Leguminobacter neodroserae Order Rhizobiales Family Rhizobiaceae Habitat: outskirts of the Mediterranean basin. 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.
Áèîëîã: The former E. coli... Escherichia muscina Order Enterobacteriales Family Enterobacteriaceae Habitat: tropics and subtropics of the Old World – Africa, Zinj Land, Asia and southern Europe. 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 bite, 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.
Áèîëîã: Another one. Photobacterium endoprotistum Order “Vibrionales” Family Vibrionaceae Habitat: all oceans of the globe, bathyal zone. 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 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.
Áèîëîã: The first cyanobacterium! Just two more descriptions to go! Nostoc volvoxoides Order Nostocales Family Nostocaceae Habitat: still freshwaters of temperate climate in the Northern Hemisphere. 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.
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