Phosphorylation of calf thymus H1 histone by calcium-activated,phospholipid-dependent protein kinase

Ca²⁺-activated, phospholipid-dependent protein kinase recently found in mammalian tissues (Takai, Y., Kishimoto, A., Iwasa, Y., Kawahara, Y., Mori, T., and Nishizuka, Y. (1979) $\text{J.}$$\text{Biol.}$$\text{Chem.}$$\text{254}$, 3692–3695) is able to phosphorylate five fractions of calf thymus histone. H1 histone serves as a preferential substrate, and approximately two moles of phosphate are incorporated into every mole of this histone. Analysis on the N-bromosuccinimide-bisected fragments of this radioactive histone has revealed that the enzyme phosphorylates preferentially seryl and threonyl residues located in the carboxyl-terminal half of this histone molecule.     

Non-H-2-linked genetic regulation of cytotoxic responses to hapten-modified syngeneic cells. I. Non-H-2-linked Ir gene defect expressed on T cells is not predetermined at the stage of bone marrow cells

Spleen cells from C3H/He or BALB.K mice immunized to the newly synthesized amino-reactive hapten 5-sulfo-1-naphthoxy acetic acid N-hydroxysuccinimide ester (AED-NH2) were stimulated in vitro with AED-NH2-modified syngeneic cells. After 5 days of culture, effector cells were assayed for their cytotoxic activity against AED-NH2-modified target blast cells. C3H/He and BALB.K mice exhibited the respective high and low anti-AED-NH2 cytotoxic T lymphocyte (CTL) responses. This contrasted with the observation that both of these H-2k strains generated potent CTL responses against aminoreactive haptens, e.g., trinitrophenyl (TNP). Because C3H.SW and BALB.B strains, which are the H-2b counterpart of the above two strains, also represented the respective high and low responders to AED-NH2 hapten, this hapten model enabled us to investigate cellular mechanisms underlying the above non-H-2-associated genetic regulation of CTL responses (C3H vs BALB non-H-2 backgrounds). The results demonstrated that there was no detectable difference between C3H/He and BALB.K strains in the lysability of target cells and the ability of stimulating cells to activate primed spleen cells. Anti-AED-NH2 CTL responses were only marginal when antigen-presenting cells (APC) were eliminated from the primed spleen cells of high responder C3H/He or (C3H/He X BALB.K)F1 mice. The addition of APC to cultures free of APC regained an appreciable CTL response in C3H/He or (C3H/He X BALB.K)F1 mice, irrespective of whether APC were derived from high (C3H/He) or low (BALB.K) responders. We have also demonstrated that allogeneic radiation bone marrow chimera (BALB.K----C3H/He) exhibited a CTL response comparable to that induced by C3H/He mice, whereas the reverse direction of allogeneic chimera (C3H/He----BALB.K) induced a marginal CTL response. These results indicate that this non-H-2-associated Ir gene defect is expressed on T cells (CTL precursors and/or helper T cells) rather than APC, and that this T cell defect is not predetermined at the level of bone marrow cells. The results are discussed in the light of the genetic and cellular mechanisms underlying non-H-2-linked Ir gene control.     

The estimation of population density of the green rice leafhopper,Nephotettix cinticeps Uhler,in spring field by the capture recapture method

The population parameters of green rice leafhopper, Nephotettix cincticeps in hibernated generation was estimated by the capture-recapture method on the gramineous weeds of resting paddy field from late in April to mid-May, 1962–1965. The difficulty of applying the capture-recapture method to this insect is caused from the low density and the low activity of the leafhopper, so that it is necessary to make the suitable plan of capture-recapture series and to construct the special method to detect the population parameters. The number of adults differed greatly among the years and among the plots in the same year. But, in general, the density was relatively high late in April, and decreased rapidly in May. The number of males was higher than that of females late in April, but decreased rapidly to become lower in May. The sampling efficiency with sweep-net depends upon the many factors, such as weather and floristic conditions; especially the atmospheric temperature and the force of wind are considered to affect greatly to the efficiency. In general, low temperature and strong wind are the cause of low sampling efficiency.     

Enhancement of natural resistance of mice to Rhodococcus equi infection by Dextran Sulfate 500

The effect of intraperitoneal injection of Dextran Sulfate 500 (DS-500, 500,000 Mr) on the intravenous clearance and host resistance to Rhodococcus equi in mice was studied. Contrary to the results seen with Listeria monocytogenes, DS-500 enhanced murine resistance to R. equi and altered organ distribution and clearance.     

Inhibition of the action of the stimulatory GDP/GTP exchange protein for smg p21 by the geranylgeranylated synthetic peptides designed from its C-terminal region

smg p21B, a member of the ras p21-like small GTP-binding protein superfamily, undergoes post-translational modifications, which are geranylgeranylation of the cysteine residue in the C-terminal region followed by removal of the three C-terminal amino acids (QLL) and the subsequent carboxyl methylation of the exposed prenylated cysteine residue. smg p21B has a polybasic region upstream of the prenylated cysteine residue. We have previously proposed that these C-terminal structures of smg p21B are essential for the action of its stimulatory GDP/GTP exchange protein, named GDP dissociation stimulator (GDS). We studied here which structure of the C-terminal region of smg p21B is important for its interaction with smg p21 GDS. For this purpose, we synthesized a peptide according to the C-terminal structure of smg p21B, which was PGKARKKSSC-geranylgeranyl-carboxyl methyl, and its variously modified peptides and examined their ability to interact with smg p21 GDS and to interfere with the smg p21 GDS action to stimulate the GDP/GTP exchange reaction of smg p21B. The results indicate that the phosphorylated form of PGKARKKSSC-geranylgeranyl stoichiometrically interacts with smg p21 GDS, that the presence of the geranylgeranyl moiety is essential for, but not sufficient for, the smg p21 GDS action, and that the presence of the methyl moiety, removal of the three C-terminal amino acids, and the presence of the polybasic amino acids also affect the smg p21 GDS action. It is likely that all the steps of the post-translational processing and presence of the polybasic region in the C-terminal region of smg p21B are related to its interaction with smg p21 GDS.