Bacterial spore

“ When the conditions are again favourable, spores germinate, giving rise to new bacilli. The germinating spore becomes elongated, and loses its bright appearance, the outer membrane becomes ruptured, and the young bacillus is set free. Certain conditions, such as the presence of oxygen in the case of the anthrax bacillus, give rise to the formation of spores; while various kinds of bacteria secure continuous existence by developing spores when there is lack of proper food material. ”

“ Fig. 10.—Bacillus subtilis. (After Strasburger.) A. Zoogloea pellicle. B. Motile rodlets. C. Development of spores.
The spore may be formed in short or long segments, the cell-wall of which may undergo change of form to accommodate itself to the contents. As a rule only one spore is formed in a cell, and the process usually takes place in a bacillar segment. In some cases the spore-forming protoplasm gives a blue reaction with iodine solutions. The spores may be developed in cells which are actively swarming, the movements not being interfered with by the process (fig. 4, D) . ”

“ Under favorable conditions bacteria multiply rapidly, but when conditions are unfavorable, they take on a spore formation and remain in a quiescent state, like the seed of a plant, waiting—it may be years—until proper conditions are present. The spores are protected by such a thick envelope and have such great potential vitality, that it is much more difficult to kill them than the developed bacteria. ”

“ The fact that the protoplasm is denser and the spore capsule thicker (the percentage of water in each is decidedly less than in the growing cell) gives the spore the property of much greater resistance to all destructive agencies than the active bacterium has. For example, all actively growing cells are destroyed by boiling in a very few minutes, while some spores require several hours’ boiling. ”

“ At first sight a spore seems as if it were the nucleus of the bacterium cell, but it is not always present when multiplication by cleavage is taking place, and when present it does not appear to take part in the fission. On the other hand, a spore, from the character of its envelope, possesses great power of resistance, so that dried bacteria, when placed in conditions favorable to germination, can through their spores germinate and resume an active existence. ”

“ When free in the field of the microscope, spores must be distinguished from fat cells, micrococci, starch cells, some kinds of ova, yeast cells, and other like objects. Spores are detected frequently by their resistance to ordinary stains and the necessity of colouring them by special staining methods. When, however, a spore has taken on the desired colour, it retains it with tenacity. In addition to their shape, size, thickened capsule, and staining characteristics, spores also resist desiccation and heat in a much higher degree than bacilli not bearing spores. ”

“ The spore-forming bacteria usually found in water are those of the subtilis group, derived largely from soil washings, and B. enteritidis sporogenes, from sewage and manure. The spores of these organisms are very resistant and survive all ordinary concentrations. Wesbrook et al. [1] found that 3 p.p.m. of available chlorine had little effect on a spore-forming bacillus isolated from the Mississippi water and the author has obtained similar results with B. subtilis.
Thomas, [2] during the chlorination of the Bethlehem, Pa., supply, found four organisms that survived a concentration of 2 p.p.m. ”

“ Large spore-forming bacteria, related to Bacillus subtilis, which form about 5-10 per cent. of the numbers. He adduced evidence [12] , [13] that these organisms exist in the soil mainly as spores, so that they may not form an important part of the active soil population.
(2) Short non-sporing organisms, related to Pseudomonas fluorescens, that are rapid gelatine liquefiers. These form another 10 per cent. of the numbers.
(3) Short rod forms that liquefy gelatine slowly or not at all, and develop colonies very slowly. These form 40-75 per cent. ”

“ The spore formation of bacteria is very simple, all or part of the living contents of the bacterium becomes surrounded by a tough wall and remains so surrounded till circumstances are favourable, when the wall bursts, its contents escapes and becomes a bacterium, capable of founding a new colony by the method of splitting we have already described. ”

“ If the surroundings are too hot, too cold, or too dry, or if they are not supplied with a proper quantity and quality of food, the bacterium becomes inactive until the surrounding circumstances change; or it may die absolutely. The spores, which finally become full-fledged bacteria, are able to stand a more unfavorable environment than the adult bacteria. ”

“ The bacteria spores, like mold spores, have a tough surface which gives them high resistance, and they contain the germ of bacteria life which can reproduce the species when favorable conditions for growth are again encountered. The bacteria spores, therefore, float through the air as do the mold spores, remaining in the dry state without nourishment for months at a time, and as soon as they light upon a moist surface containing the elements for growth, even to a very small degree, they reproduce the rod-shaped bacteria form, which begins to multiply itself again by the simple division method. ”

“ Resting Stage.—Spore Formation.—Conditions influencing spore formation: In an old culture nothing may be left but spores. It used to be supposed that spores were always formed, so that the species might not become extinct, when
(a) The supply of nutrient was exhausted. [Pg 138]
(b) The medium became toxic from the accumulation of metabolic products.
(c) The environment became unfavourable; e. g., change of temperature.
This is not altogether correct; e. g., the temperature at which spores are best formed is constant for each bacterium, but varies with different species ”

“ Although most bacteria spores are killed by boiling for 10 or 15 minutes, there are a few species of extremely high resistance which have been known to remain alive after several hours’ boiling. Spores of this nature are infrequent, however, and the packer might as well forget that they exist. Not one case of spoilage out of a hundred is caused by the presence of such spores, and if all food products were cooked a length of time sufficient to kill all bacteria spores which might possibly be present, the foods would be cooked to death, and unfit to eat. ”

“ It is these tubes, and the spores thrown from them, which you see forming a kind of halo round the dead fly as it clings to the pane. Other fungi in the same way kill the silkworm and the caterpillars of the cabbage butterfly. Nor is it only the lower animals which suffer. When we once realise that fungus spores are floating everywhere in the air, we can understand how the terrible microscopic fungi called bacteria will settle on an open wound and cause it to fester if it is not properly dressed. ”

“ Not only does the close resemblance of the Bacteria to unquestionable plants, such as the Oscillatorioe and the lower forms of Fungi, justify this conclusion, but the manufacturing test settles the question at once. It is only needful to add a minute drop of fluid containing Bacteria, to water in which tartrate, phosphate, and sulphate of ammonia are dissolved; and, in a very short space of time, the clear fluid becomes milky by reason of their prodigious multiplication, which, of course, implies the manufacture of living Bacterium-stuff out of these merely saline matters. ”

“ Special methods must be used for the isolation of special organisms; phenol-gelatine, Elsner medium, indol reaction, "shake" cultures, Parietti broth, etc., must often be resorted to for special bacteria. Spores of bacteria may always be numerically estimated by adding the suspected water or sewage to gelatine, and then heating to 80° C. for ten minutes before plating out. This temperature removes the bacilli, but leaves the spores untouched. ”

“ The high temperatures are fatal to bacteria, moist heat being more destructive than dry heat, and adult cells are more easily killed than spores. A temperature less than 212°F. will kill many organisms and boiling will kill every pathogenic organism that does not form spores. Some spores are not destroyed after prolonged boiling and some will withstand a temperature of 120°C. As a practical fact, however, boiling water kills in a few minutes all cocci, most bacilli, and all pathogenic spores, though anthrax and tetanus are harder to kill than are the spores of other bacteria. ”

“ If the division takes place in one plane, Diplococci are formed; if in two directions Tetracocci, or Tablet-cocci, are formed. On account of this multiplication by fission, the generic name of Schizomycetes, or fission-fungi, has been given to bacteria.
Spores.—A second method by which bacteria propagate is by spores. These bodies are distinguished by their remarkable power of resistance to the influence of temperature and the action of chemical reagents. Some of them will resist their immersion in strong acid solutions for many hours ”

“ Studies on the packaging and stability of foods under various conditions of humidity, temperature, and radiation will lead to better processing and storage.
Learning how microbial spores are transported by air is important to biology, agriculture, and medicine. Besides spreading crop destruction, microbial spores produce allergic responses in some human beings. To obtain the facts, not only the biology of micro-organisms but also the weather factors that induce the flight of mature spores must be known. ”

“ The very few students who have made quantitative estimations have obtained very unsatisfactory results. In bacterial or protozoal estimations, the shaking of the soil suspension separates the unicellular individuals, so that in the final platings each individual from the soil theoretically gives rise to one [123] colony on the medium. In the case of fungi, the organisms may be in the form of unicellular or multicellular spores or larger or smaller masses of unicellular or multicellular mycelium differing for each particular species or phase of development within the single species. ”

“ It is notorious that the spores of bacteria and the higher fungi resist changes of temperature, desiccation, and the action of physical and chemical agents, to an astonishing extent. Vegetative reproduction is extremely active under favourable conditions, and resting reproductive bodies of varying morphological character are produced in great abundance. Amongst fungi, a phenomenon known as heteroecism is developed as a special adaptation to parasitic conditions, and recalls the similar adaptations in many animal parasites. ”

“ He lived, this man of the long-forgotten past, as all men live—getting his food, begetting his kind, loving, hating, fighting, rejoicing in the coming of the spring, pleased with his own person and its adornment, repeating the tales of his forefathers about the fire—then vanishing into the all-containing soil of the earth whence he came.
What man, once quickened by the spirit of the earth and touched by its thousand sweet influences, would ever think of resigning this mortal inheritance, with all its certainty of dissolution, for an immortality in some unknown, untried sphere of existence? ”

“ The production of nitrogen for plant food in peace and explosives in war is more and more important. ”

“ Under the microscope you clearly perceive that these insects have organs, orifices, excrement; they do, most emphatically, copulate. Escorted on the one side by the Bos or Warble, on the other by the Hessian Fly, Miss Ormerod advanced statelily, if slowly, into the open. Never did her features show more sublime than when lit up by the candour of her avowal. “This is excrement; these, though Ritzema Bos is positive to the contrary, are the generative organs of the male. I’ve proved it.” ”

“ Whether the glad flames sport amid the long dry grass of last year, or the plough turn up a deep layer of the exhaustless soil, or flocks of prairie-chickens fly up from every little valley, images of life, joy, and plenty belong to the scene. The summer flowers are not more cheerful than the spring blaze, the spring blackness of richness, or the spring whirr and flutter. The sky is alive with the return of migratory birds, swinging back and forth, as if hesitating where to choose, where all is good. ”

“ To sunshine we fly from too piercing an air;
But love's ardent fire burns always the same,
No winter can cool it, no summer inflame.
But see the pale moon, all clouded, retires;
The breezes grow cool, not Strephon's desires:
I fly from the dangers of tempest and wind,
Yet nourish the madness that preys on my mind.
Ah, wretch! how can life be worthy thy care? ”

“ A brown spotted lady-bug climbed the dizzy height of a grass blade, and Tom bent down close to it and said, "Lady-bug, lady-bug, fly away home, your house is on fire, your children's alone," and she took wing and went off to see about it —which did not surprise the boy, for he knew of old that this insect was credulous about conflagrations, and he had practised upon its simplicity more than once. ”

“ Diagram of the same cell of a tentacle, showing the various forms successively assumed by the aggregated masses of protoplasm. ”

“ But time is only another liar, so go along the wall a little further: if blackberries prove bitter there’ll be mushrooms, fairy-ring mushrooms, in the grass, sweetest of all fungi. ”