In previous papers, it was demonstrated that ribosome fractions were obtained from the cell-free extracts of Mycobacterium 607 (M. 607) and BCG by means of preparative ultracentrifugation.
This report deals with influence of antibiotics on the¹⁴C-amino acids incorporation into the protein fraction by the ribosome systems prepared from M. 607 and BCG.
M. 607 and BCG were cultured with a tween 80 synthetic medium. The cells were harvested at an exponential phase, and washed with and resuspended in the 0, 01 M of tris buffer containing 0, 01 M of MgCl₂. The cell-free extracts of the washed cells were prepared by passing through the French pressure cell at 400 kg/cm² followed by centrifugation at 5, 000 g for 20 minutes. The ribosome fractions were isolated from the cell-free extracts by ultracentrifugation at 105, 000 g for 120 minutes after removal of fractions which were precipitated at 20, 000 g for 60 minutes.
Studies were carried out on influence of antibiotics on the¹⁴C-amino acids incorporation into the protein fractions by these ribosome systems and cell-free systems.
Results obtained were as follows:
1) The cell-free extract prepared from M. 607 was capable of incorporate ¹⁴C-amino acids into its, protein fraction in the presence of ATP and its generator. This ¹⁴C-amino acids incorporation was inhibited by the addition of 50 μg/ml of chloramphenicol (CM) and tetracycline (TC).
2) Furthermore, the 14C-amino acids incorporation into the protein fractions by the ribosome fractions prepared from M. 607 and BCG were inhibited by the addition of 50 μg/ml of CM, TC, erythromycin (EM) and streptmycin (SM), but not inhibited by isoniazid.
3) When the ribosomes isolated from normal cells of M. 607 were incubated with 100 μg/ml of EM and TC at 37°C for 2 hours, analytical centrifugation patterns revealed disappearance of 94, 1 S particles and dissociation of 74, 4 S particles into 45, 6 S and 30, 2 S particles.
From these results, the mode of action of TC, EM and SM, and Selective toxicitiesof them were discussed.

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It was demonstrated in the author's 1 st report that DNA fraction isolated from Vibrio parahaemolyticus had lethal toxic effect to mice. In this report the immuno-serological studies on the DNA isolated from Vibrio parahaemolyticus were carried out. Purified DNA derived from Vibrio parahaemolyticus was injected intramuscularly to rabbits with complete adjuvant. High anti-DNA fraction titer was demonstrated by sensitized haemaggulutination reaction. The pretreatment by immunized rabbit serum with DNA fraction was found to have remarkable protective action against the challenge of 10 times doses of toxic fraction and remarkable protective effect against infection with Vibrio parahaemolyticus. These immuno-serological results also suggest that DNA derived from Vibrio parahaemolyticus might have a significant role.

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It is the purpose of this peport to present the findings concerned with the role of the thymus and Bursa of Fabricius (B. F.) in the development of lymphoid tissue and immunologic capacity in chicken. Using Rhode-Horn F₁ as experimental chicken, the authors performed surgical thymectomy and bursectomy at the time of hatching, or hormonal bursectomy by the injection of testosterone propionate into 5-day chick 4embryos. The following results were obtained.
1) It was confirmed that lymphocytopoiesis in the thymus and B. F. begins in epithelial buds of chick embryos at 12-14 days of incubation, and before hatching lymphoid tissue is confined to both the organs. In fact, the spleen and intestine are as yet lacking in demonstrable lymphoid follicles at hatching, and the development of lymphoid tissue in thse organs commences to appear 1-2 weeks after hatching.
2) Chiken thymectomized or bursectomized at hatcing showed a slight diminution in lymphocyte population of the blood stream and poor development of lymphoid follicles in the spleen and intestine. Furthermore, extirpation of both the organs resulted in the striking depression of lymphocyte level in the blood stream and of the development of lympoid follicles.
3) Complete bursectomy, surgical or hormonal, weakened or removed the ability of the birds to produce the antibodies in response to typhoid bacilli and sheep erythrocytes introduced. However, thymectomy had no influence on the production of circulating antibodies.
4) Thymectomy prolonged remarkably the elimination of homologous erythrocytes labelled with ⁵¹Cr from the blood stream, while bursectomy prolonged slightly. The life-span of homologous erythrocytes in the blood stream of the group in which both the organs were extirpated reached near that of the autologous erythrocytes in the normal group. This may be taken to indicate that chicken can be rendered tolerant toward homologous erythrocytes by thymectomy at hatching.
From the above-described data, the authors can suppose that the thymus and B. F. are primarily lymphopoietic organs in embryonal and neonatal life, and make a major contribution to the central supply of precursory lymphoid cells, capable of becoming immunologically competent, to lymphoid follicles of whole body. It may be, morever, suggested that descendants of lymphoid cells originating in both the organs have different functions from each other in immunologic responses, i. e., lymphoid cells descending from the B. F. are responsible for the circulating antibody production through the differentiation to plasma cells by antigenic stimuli, and lymphoid cells descending from the thymus are responsible for the homograft immunity, probably, through the cellular antibody of lymphocytes.

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1. The process of toxin production was investigated withClostridium botulinumtype A, strain 190 and type B, strain Lamanna, both belonging to the proteolytic group ofClostridium botulinum. In theformer, no increase in the toxicity was observed after the trypsin treatment. However, in the latter, the toxicity increased by about 10 to 100 times with trypsin even in the late stage of incubation.
2. The similar experiments were carried out withClostridium botulinumtype C, strain Stockholm, and type E, strain VH, both belonging to the non-proteolytic group ofClostridium botulinum. In the former, no distinct increase in the toxicity was observed after the trypsin treatment. Onthe contrary, the toxicity increased by about 100 to 1, 000 times with trypsin in the latter.
3. The activation phenomenon ofClostridinum botulinumtoxin by trypsin seems to have no direct relationship with the proteolytic character of the strain.

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