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Phage (or bacteriophage) is a general term for viruses destructive to bacteria. Their existence was first established in 1915 and since that time phages have been studied intensively. In laboratory conditions, their addition to a culture of bacteria in solutioh results in bacteriolysis: the bacteria swell and then suddenly disappear. During this process, the phage enters the bacterial cell and multiplies. Phagcs are angular or spherical in shape, some have a tail. Their size ranges between 8 and 70 mµ.
Among the bacteria found to be infested with phage are bacterium, bacillus, micrococcus, corynebacterium, vibrio and actinomyces. Colon bacteriophage is found in human faeces and sewage, dysentery bacteriophage in horse and pig manure, and staphylococcus and streptococcus phage in infected human tissue. Other types of phage are found in soil and decomposed plants. Cultivation and examination of phages, using an electron microscope, is relatively simple and their study has become an important field of bacteriology. In order to unify research, the most widely-used phage for research purposes is the T system which infests strain B of E coli.
DNA, or deoxyribonucleic acid, is a polymer of nucleotides made up of one part of phosphoric acid, one part of D-deoxyribose sugar and one part of purine or pyrimidine base. It has been established that DNA is a carrier of genetic information within the nucleus of all living cells and much complex rcsearch has been done into the structure of DNA and the so-called "genetic code". Phages, which contain DNA, have played an important part in these genetic studies.
Enzymes can be defined as organic catalysts of high molecular weight contained in or secreted by the cells of living organisms. Enzymes are composed of protein but they may contain other, non-protein, compounds as well. Their significance is far-reaching and most life processes require their presence, either in a simple reaction or in chain reactions involving many different enzymes. At the present time, some 700 enzymes have been classified.
The function and behaviour of enzymes is used in many industrial processes, notably fermentation and brewing; for example, alcohol fermentation, acetone-butanol fermentation, acetate fermentation, butyric acid fermentation, the fermentation of organic acids, and in the food industry for the production of cheese, miso ( fermented bean paste), shoyu (soybean sauce), bread and pickles. Also enzymes are important catalysts in the preparation of antibiotics, such as penicillin and streptomycin, and certain vitamins.
Aspergillus oryzae is a kind of sac fungus of the ascomycete group. It generates a woolly fungal growth at a temperature of 37 ºC. The colour changes from yellow to yellow-green as the spores mature. Organic acids of the generation system are kojic acid and gluconic acid; enzymes include amylase, maltase, invertase and inulilase. Aspergillus oryzae is added to steamed rice (koji) during the sake (rice-wine) manufacturing process, when the amylase enzyme converts rice-starch into fermentable sugar. It is also used in the preparation of amazake (a sweet drink made from fermented rice), shoyu (soybean sauce) and miso ( fermented bean paste).
Bacillus natto, a rod-shaped bacillus, is found on rice straw. It is capable of rapid reproduction of spores. In Japan, bacillus natto is used for the preparation of natto an important protein food. Natto is made by wrapping steamed or boiled soybeans in rice straw; a culture of bacillus natto grows within the wrapping, covering the beans with a sticky velum.
Bacillus natto improves the digestibility of soybeans and yields vitamin B2. In addition, it produces an antibiotic substance which is inhibiting to toxic bacilli in the intestine. Traditionally, natto has played an important part in the vegetarian diet of Zen Buddhist monks and among the older generations of Japanese people natto is a regular breakfast food.
The contents of this site are excerpted from THE OFFICIAL RECORD OF TIME CAPSULE EXPO'70(March 1975). Please note that company and organization names may differ from those of the current ones.
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