Rotarides Mihály (szerk.): A Magyar Természettudományi Múzeum évkönyve 33. (Budapest 1940)
Tóth, L.: The protein metabolism of the Aphids
lowing reproduction. I compared the weights of the full grown apterous viviparous females of a species, multiplying very quickly (Aphis sambuci L.) with those of the new born individuals, and have found, that the weight of the latters is about l / 20 of that of the former ones. One single female can produce offspring sometimes over 20 a day. This means, that an Aphid, strongly multiplying, has to replace daily the complete quantity of its protein content. It is quite sure, that the animal is completely unable to cover this gigantic need in protein from its nourishment, so poor in protein. What is the way, therefore, by which it is still getting it? I stated, in 1933, that in the normal and regularly nourishing Aphids there is always a well developed mycetome present, while in the degenerated and short-living sexual individuals, which do not nourish at all, the mycetome is either missing completely (males), or reduced so much, that the rest of symbiotic microorganisms is sufficient for the infection of the next generation only. My researches prove that the symbiontic microorganisms play some unreplaceable metabolic rôle in the household of the host-animal, in other words, one must suspect some connenction between protein provision and symbiosis, as may be supported by some arguments. PEKLO, who studied the systematics of the symbionts of Aphids, came to the result, that they belong to the Azotobacters, that is, they belong to a group, which is known of the capacity of being able to assimilate the atmospheric nitrogen. SCHOEL (1934) undertook breeding experiments with symbiontic microorganisms. His results prove that symbionts have an important rôle in the protein metabolism of the host. In his opinion they are able to use, in great extent, of the protein products of the host. On the contrary, he was not successful to show whether they are able assimilate atmospheric nitrogen. ROBERG (1956) was studying the biology of this microorganism group and proved, that a great part of the Azotobacterprotein becomes soluble by autolysis after death of the microorganism. The next question therefore is, whether there is a way, by which the symbiont protein gets soluble in the bodies of the Aphids? The mass of symbionts is — compared to the size of the Aphids — very considerable. A part of it serves to the infection of the embryos, an other part is annihilated in the body of the host. One way of the destruction of symbionts is the phagocytosis through oenocytes found in each Aphid. The process, however, is a very slow one, so that the protein quantity, gained that way by the animal,
