In Vitro Studies on the Immunological Memory for Antibody Response to Bovine Serum Albumin

Immunological memory for T and B cells was studied in an in vitro culture system with spleen cells from mice primed with bovine serum albumin (BSA). Spleen cells taken from mice immunized at various times previously with a single intravenous injection of alum-precipitated (AP) BSA and bacterial endotoxin (ET) were cultured in Marbrook's system with dinitrophenylated (DNP) BSA as the in vitro antigen. In the cultures of spleen cells obtained from mice primed more than 14 days previously, an IgG-predominant anti-BSA response was generated. However, no anti-BSA response was observed in the culture of spleen cells taken from mice primed 7 days previously (day 7 spleen cells). The failure of day 7 spleen cells to generate an antibody response in vitro was shown to be attributable to both the lack of B memory cells and the effect of “suppressive” macrophages induced by ET. On the other hand, anti-BSA memory in the spleen of mice primed with AP-BSA plus ET and 2 months later challenged with AP-BSA matured within 7 days and declined rather quickly by 30 days after the challenge. The difference in the time course of the generation of memory between the spleen cells from primary and from secondary immunized mice might be attributable to the difference in the maturation of memory B cells, since the time course of the development of memory T cells after the secondary immunization was similar to that observed after primary immunization.     

Deoxyribonucleoside-3',5'-cyclic silanediyl derivatives: formation and properties

Formation of 3',5'-O-(dialkylsilanediyl)deoxyribonucleosides was studied. Treatment of deoxythymidine in DMF with bifunctional silylating reagent such as di-t-butyldichlorosilane and diisopropyldichlorosilane in the presence of imidazole gave the expected silanediyl derivatives. The structure was confirmed mainly by NMR spectroscopy. The stability of these cyclic silyl derivatives toward hydrolysis is also described.     

Preparation of 3-Methyl-3-(substituted phenyl)-pyruvic Acid

The relationships between dietary levels of the essential amino acids and hepatic polysome profiles of rats were investigated with special attention to the amino acid requirement pattern for the maximum rat growth as determined by other investigators. The basal diet contained a 7% essential amino acid mixture and a 3% non-essential amino acid mixture, with appropriate amounts of other nutrients. Rats were fed test diet for 5 hours and then the polysome profile was determined. The amounts of essential amino acids needed for maximum aggregation of polysome were low for methionine-cystine, leucine and tryptophan as compared with requirements for maximum growth. But in other essential amino acids, the amounts were in almost the same range as those reported for maximum growth by others. The differences between the amino acid requirement patterns for maximum aggregation of hepatic ribosomes and for maximum growth of rats might be due to a difference in amino acid requirements of the liver and whole body. Therefore, the hepatic polysome profile might be used to measure the effect of amino acid supplementation on dietary proteins. The requirement pattern of essential amino acids in other organs may be studied by polysome profile determination.     

Presence of acid phosphatase activity in heavy bodies of sea urchin eggs

Cytochemical studies were made on the acid phosphatase (Acp-ase) in the heavy bodies of eggs of the sea urchins, Hemicentrotus pulcherrimus and Temnopleurus toreumaticus, from the stage of mature unfertilized eggs to the late gastrula stage. High Acp-ase activity was found in masses composed of ribosome-like granules in the heavy bodies from the early stage of the formation of heavy bodies until the time of their disappearance, whereas the annulate lamellae and the space between the annulate lamellae and the masses packed with ribosome-like granules did not have activity. This activity was inhibited by the addition of 0.01 M NaF to, or the omission of substrate from, the Gomori medium. Using the reaction products of Acp-ase and the masses of ribosome-like granules as markers of heavy bodies, we found small groups of tightly packed ribosome-like granules that were not surrounded by annulate lamellae. The function of Acp-ase in the heavy bodies is still unknown.     

Transition in the Character of Immunological Memory in Mice after Immunization

The immunological memory in antibody response of mice to bovine serum albumin was investigated at the level of IgM and IgG antibody-forming cells. The antigen at a dose much lower than required for eliciting a detectable level of the primary antibody response could latently activate the immune machinery to an extent adequate for specific recall, whereas higher doses of antigen were effective in evoking strong anamnestic response. The potentiality to develop the anamnestic response was found even in the latent phase of the primary antibody response and was maintained for more than 2 months. The immunological memory acquired in an early phase after the primary immunization mainly involved IgM antibody response and late memory concerned IgG response.     

Assembly systems in molecular biology: A graph theory of genetic complementation between two related species

In this report I discuss the interpretation of the data of genetic complementation in vivo of assembly systems between two related species, such as the complementation of structural proteins between related bacteriophages. It is suggested that such experiments reveal interactions between gene products that are overlooked in many other experiments. A mathematical model based on the graph theory is presented, assuming that the assembly system consists of gene products and interactions between them. The model shows that information from the complementation experiment is limited to those interactions which are mismatching if the interacting gene products are produced by different species. Moreover, it shows that the number and positions of mismatching interactions cannot always be determined uniquely by the data of complementation. However, there is a mathematical method by which one can calculate all the possible solutions for the number and positions of mismatching interactions from experimental data. Actual calculation is performed for a simple example. Thus, the model clarifies validity and limitation of complementation experimiments between related species.     

Carotenoid production in <Emphasis Type="Italic">Bacillus subtilis</Emphasis> achieved by metabolic engineering

The carotenoid synthetic genes, crtM and crtN, derived from Staphylococcus aureus, were introduced into B. subtilis, resulting in yellow pigmentation. Absorption maxima of pigments and MALDI-TOF mass spectrometry demonstrated that the pigmented strain accumulated two C₃₀ carotenoids, 4,4′-diapolycopene and 4,4′-diaponeurosporene. A survival test using H₂O₂ revealed that the pigmented strain was more resistant to oxidative stress than the strain harboring an empty-vector. These findings indicate that B. subtilis can produce carotenoids, and the strain accumulating the carotenoids, CarotenoBacillus, will become a basal host for production of C₃₀ carotenoids and evaluation of their antioxidative effects.     

QGP-1 cells release 5-HT via TRPA1 activation; a model of human enterochromaffin cells

Molecular and Cellular Biochemistry - Recently, we discovered that transient receptor potential ankyrin1 channel (TRPA1) is highly expressed in human and rat enterochromaffin (EC) cells, and those...