Primary structures of the mRNAs encoding the rat precursors for bradykinin and T-kinin. Structural relationship of kininogens with major acute phase protein and alpha 1-cysteine proteinase inhibitor

Three types of cloned cDNA sequences for rat low molecular weight prekininogens were isolated and determined by molecular cloning and sequence analysis. The deduced amino acid sequences indicated that one, termed K-prekininogen, represents the counterpart of the known low molecular weight prekininogen present in other mammals, while the other two, called T-prekininogens, contain a novel T-kinin sequence which was recently identified from rat plasma. Although T- and K-prekininogens are highly homologous with each other, both of the T-prekininogens contain methionine, instead of arginine or lysine, as an amino acid preceding T-kinin and exhibit two consecutive amino acid deletions in the preceding region of T-kinin as compared with K-prekininogen. The former finding accounts for the previous observation of strong resistance of T-kininogens to cleavage with trypsin or kallikreins, while the latter finding has been explained by the structural analysis of genomic clones in which T-kinin-coding exon is contracted at its intron junction. A partial nucleotide sequence reported recently for the rat major acute phase protein (alpha 1-MAP) mRNA was found to be extremely related to the corresponding portion of the rat T-prekininogen mRNA. Furthermore, consistent with the previous report of the structural identity of major acute phase protein and alpha 1-cysteine proteinase inhibitor, kininogen closely resembles not only the former but also the latter in the amino acid compositions. The interrelationship among the triad of these proteins has been discussed.     

Light and electron microscopic studies on capillaries of the goat cardiac muscle with special reference to the topographical relationship between the vessels and Purkinje fibers

The capillaries of the cardiac muscle were investigated in the goat by means of light microscopy, transmission electron microscopy and scanning electron microscopy, and the following results were obtained. The capillaries of the working cardiac muscles were numerous, arranged mainly parallel to the long axis of muscle cells and formed dense elongated networks. On the contrary, those of the terminal Purkinje fibers were relatively few in number, oriented in various directions and formed loose and circularly meshed networks surrounding the fibers. Such findings were discussed in correlation with the physiology and functional morphology of various types of the cardiac muscle cells.     

Fate of recombinants of the rat mandibular epithelium with cranial ectomesenchymal cells of different sources in vitro

The recombinants of the mandibular molar bud epithelia with cranial ectomesenchymal cell groups from several different sources--mandibular molar area, tongue anlagen, and lateral nasal process--were cultured. Dental laminalike buds were developed in each of the recombinants (incidence of development 38-86%). In the heterotrophic recombinants, heterotypic differentiation of mandibular epithelium was also induced. However, the foreign ectomesenchymal cells were not induced heterotypically by the epithelial genetic factor, but the mesenchymal genetic factor is maintained. It is suggested that mandibular molar bud epithelia have potency to proliferate into mesenchyme under non-organ-specific influences of ectomesenchymal cells and that presumptive mandibular mucosal epithelia have multipotency for differentiation sensitive to inductive influences by the heterotypic cranial ectomesenchymal cells but that the mandibular molar bud epithelia have no heterotypic inductive activity for the differentiation of cranial ectomesenchymal cells.     

A scanning calorimetric study of the thermal denaturation of the lysozyme of phage T4 and the Arg 96----His mutant form thereof

High-sensitivity scanning calorimetry has been employed to study the reversible thermal unfolding of the lysozyme of T4 bacteriophage and of its mutant form Arg 96----His in the pH range 1.80-2.84. The values for t1/2, the temperature of half-denaturation, in degrees Celsius and for the enthalpy of unfolding in kilocalories per mole are given by (standard deviations in parentheses) wild type t1/2 = 9.63 + 14.41 pH (+/- 0.58) delta Hcal = 5.97 + 2.33t (+/- 4.20) mutant form t1/2 = -19.84 + 21.31 pH (+/- 0.51) delta Hcal = -8.58 + 2.66t (+/- 4.48) At any temperature within the range -20 to 60 degrees C, the free energy of unfolding of the mutant form is more negative than that of the wild type by 3-5 kcal mol-1, indicating an apparent destabilization resulting from the arginine to histidine replacement. The ratio of the van't Hoff enthalpy to the calorimetric enthalpy deviates from unity, the value expected for a simple two-state process, by +/- 0.2 depending on the pH. It thus appears that the nature of the unfolding of T4 lysozyme varies with pH in unknown manner. This complication does not invalidate the values reported here for the temperature of half-completion of unfolding, the calorimetric enthalpy, the heat capacity change, or the free energy of unfolding.     

Studies of Sl/Sld in equilibrium with +/+ mouse aggregation chimaeras. II. Effect of the steel locus on spermatogenesis

Mutant mice of Sl/Sld genotype are deficient in melanocytes, erythrocytes, mast cells and germ cells. Deficiency of melanocytes, erythrocytes and mast cells is not attributable to an intrinsic defect in their precursor cells but to a defect in the tissue environment that is necessary for migration, proliferation and/or differentiation. We investigated the mechanism of germ cell deficiency in male Sl/Sld mice by producing aggregation chimaeras from Sl/Sld and +/+ embryos. Chimaeric mice with apparent white stripes were obtained. Two of four such chimaeras were fertile and the phenotypes of resulting progenies showed that some Sl/Sld germ cells had differentiated into functioning sperms in the testis of the chimaeras. In cross sections of the testes of chimaeras, both differentiated and nondifferentiated tubules were observed. However, the proportions of type A spermatogonia to Sertoli cells in both types of tubules were comparable to the values observed in differentiated tubules of normal +/+ mice. We reconstructed the whole length of four tubules from serial sections. Differentiated and nondifferentiated segments alternated in a single tubule. The shortest differentiated segment contained about 180 Sertoli cells and the shortest nondifferentiated segment about 150 Sertoli cells. These results suggest that Sertoli cells of either Sl/Sld or +/+ genotype make discrete patches and that differentiation of type A spermatogonia does not occur in patches of Sl/Sld Sertoli cells.     

Micelle formation of diacylglycerophosphocholines in organic solvents I. effects of the solvents on krafft points

Krafft points of diacylglycerophosphocholines (PC) were measured in alkanes-cyclohexane solutions by differential scanning calorimetry, and it was found that they were regularly increased following the increase in alkane content in the solutions and the chain length of the alkanes. From these results it was deduced that the mixing of PC with alkanes occurred in the gel state of the PC, but not in micelles at higher temperatures above the Krafft points. where micellar solutions are provided. The penetration of alkanes into gel state PC was found to be dominated by Langmuir type interaction, and the affinity of alkanes increases with increasing in chain lengths. Above the Krafft points, the micelle formation was confirmed by using the fluorescence probe technique.     

Presence of mast cell precursors in the yolk sac of mice

Concentration of mast-cell precursors in hematopoietic tissues of mouse embryos was evaluated by a limiting dilution method. Cells from yolk sacs, livers, and bodies of (WB x C57BL/6)F1 (hereafter called WBB6F1)- +/+ embryos were injected directly into the skin of adult WBB6F1-W/Wv mice which were genetically depleted of tissue mast cells. Concentration of mast-cell precursors was calculated from the proportion of injection sites at which mast cells did not appear. Since the concentration of mast-cell precursors in the yolk sac was about 30 times as great as that of embryonic body at Day 9.5 of the pregnancy, the mast-cell precursors seemed to be generated within the yolk sac. The concentration in the yolk sac reached the maximum level at Day 11, and then dropped markedly at Day 13. In contrast, mast-cell precursors increased from Day 11 to Day 15 in the fetal liver. As a result, the concentration of 11-day yolk sacs was comparable to that of 15-day fetal liver. Although intravenous injection of 15-day fetal liver cells (2 x 10(6)) rescued the general mast-cell depletion of WBB6F1-W/Wv mice, the intravenous injection of the same number of 11-day yolk sac cells did not rescue it. In contrast with fetal livers, yolk sacs scarcely contained hematopoietic stem cells which were measured by spleen colony formation. Therefore, the mast-cell precursors of the yolk sac may not originate from such stem cells.     

Necessity of IgE antibodies and mast cells for manifestation of resistance against larval Haemaphysalis longicornis ticks in mice

Genetically mast cell-deficient WBB6F1-W/Wv mice showed an apparent defect in manifestation of the resistance against larval Haemaphysalis longicornis ticks, but their serum IgE levels increased more than 100-fold after the second tick infestation. Immune sera obtained from the WBB6F1-W/Wv mice were adoptively transferred to the other WBB6F1-W/Wv mice which had received intracutaneous injections of WBB6F1-+/+ mouse-derived cultured mast cells. Because the resistance against ticks was detectable only when both mast cells and IgE antibodies were available, immediate hypersensitivity reaction appeared to have a physiologic role in the manifestation of the resistance against H. longicornis ticks.