Protein kinase C activity in platelets from spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY)

Calcium-activated phospholipid dependent protein kinase (protein kinase C) activity in platelets was measured in 4, 12, and 20-week-old SHR and WKY. At age 4-weeks, there was no significant difference in protein kinase C activity and systolic blood pressure between SHR and WKY. In 12 and 20-week-old SHR, both protein kinase C activity and systolic blood pressure were significantly higher than in the age-matched WKY. These results suggest that protein kinase C may be involved in the control of blood pressure in SHR and WKY.     

Selective phagocytosis of gram-positive bacteria and interleukin 1-like factor production by a subpopulation of large granular lymphocytes

There has been a consensus that a large granular lymphocyte (LGL) population with natural killer (NK) function is nonadherent and nonphagocytic. However, a significant proportion of the nonadherent cells purified by the two-step depletion of adherent cells with a plastic surface and nylon wool columns engulfed Sta. aureus into their cytoplasm. These cells were morphologically identified as LGL in light and electron microscopies. Two-color immunofluorescence tests, furthermore, demonstrated that Leu-11+ LGL, Leu-11+7-, and Leu-11+7+, but not Leu-11-7+, phagocytosed Sta. aureus. Among the particles tested here, only Gram(+) bacteria were preferentially phagocytosed, whereas Gram(-) bacteria, other large-sized microbes (e.g., baker's yeast and Candida albicans), latex, silica, and carbonyl iron were not. LGL exhibited a substantial level of bactericidal activity against Sta. aureus, although the level was one third of that mediated by monocytes. When Gram(+) bacteria were incubated with nonadherent cells for 18 hr, significant amounts of interleukin 1 (IL 1)-like factors (or IL 1 itself) as well as interferon were detected in the supernatants. On the other hand, this incubation did not induce interleukin 2 (IL 2). The IL 1-like factor producer cells were demonstrated to be the low-density lymphocytes on Percoll separation and to have the Leu-11+ phenotype. The phagocytosis was suggested to be an important stimulus in producing IL 1-like factors from LGL. Thus, the treatment of cells with cytochalasin B, a microfilament disrupting agent, completely abrogated both phagocytosis and IL 1-like factor production. Some cell wall components of Gram(+) bacteria might be important to a recognition process of the phagocytosis, since the protoplasts of Sta. aureus, when prepared by the treatment of bacteria with lysostaphin, were no longer phagocytosed by LGL. The present results therefore identify an additional unique characteristic similar to, but not identical with, the myelomonocytic nature of Leu-11+ LGL.     

Examination of protein sequence homologies: III. Ribosomal protein YS25 fromSaccharomyces cerevisiae and its counterparts fromSchizosaccharomyces pombe,rat liver,andEscherichia coli

Summary The sequences of the ribosomal proteins YS25, SP-S28, RL-S21, and Ec-S6, fromSaccharomyces cerevisiae, Schizosaccharomyces pombe, rat liver, andEscherichia coli, respectively, have been examined using a computer program that searches for homologous tertiary structures. Matrices of comparisons among the eukaryotic sequences show that they match each other sequentially without any internal gaps. The average values of the correlation coefficients obtained from the comparison matrices are higher for the first halves of the sequences than for the latter halves. This result suggests that the first halves of the sequences may represent a more important domain than the latter halves. The comparison matrices between the eukaryotic and bacterial sequences of ribosomal proteins, however, do not show sequentially arranged homology, though there are six well-matching segments arranged in different orders in the two types of sequences. This implies that the eukaryotic sequences of the ribosomal protein were reconstituted by two internal transpositions and six deletions of 4–12 residues each from the ancestral sequence during the divergence between bacterial and eukaryotic genes. These findings may give insight into structural and quantitative studies of evolutionary divergence between eukaryotes and prokaryotes.     

Behavior of Chloroplast Nucleus during Chloroplast Development and Degeneration in Chlamydomonas reinhardii

Changes in morphology of chloroplast nuclei (cp-nuclei), totalcp-DNA content, number of cp-nuclei, oxygen-evolution activityand chlorophyll (a and b) content were examined during the degenerationand development of chloroplasts, using Chlamydomonas reinhardiicells which had been incubated on solid medium for various periods. Under 4'-6-diamidino-2-phenylindole (DAPI) epifluorescence microscopy,each cell that had been incubated for 7 days had one cell nucleus,one cup-shaped chloroplast and about 10 small, dispersed cp-nucleiin the chloroplast. One day after incubation of these cellson fresh medium, the cell volume and cp-nuclei increased insize 2-3 fold, but rapidly decreased in size after cell division.After about 7 days of incubation, cells ceased to divide andcp-nuclei began to associate with each other. At about 20 daysthey formed a ring-shaped structure surrounding the pyrenoid,followed by condensation into one cp-nuclear particle near thepyrenoid. When 41-day-old cells, having only one cp-nucleus,were reinoculated on fresh solid medium, the cp-nucleus increasedin size 2–3 fold, divided into several cp-nuclear particlesand then dispersed into the chloroplast, forming a bead-likestructure, before cell division. From microscopic fluorometry,a 4-fold increase in total cp-DNA content per chloroplast, withoutan increase in the number of cp-nuclear particles per chloroplast,occurred one day after the start of the experiment and one dayafter reinoculation of 41-day-old cells onto fresh medium. Theprocess of condensation of dispersed cp-nuclear particles intoone cp-nucleus during degeneration of the chloroplast was notaccompanied by any change in total cp-DNA content per chloroplast.A large peak of oxygen-evolution (0.6–0.9 pmoles/cell/hour)was seen one day after inoculation and reinoculation of thecells. The chlorophyll content (a+b) was high (1.2–2.2pg/cell) during the first week of incubation, after which itgradually decreased. (Received December 18, 1985; Accepted April 2, 1986)     

Generation of activated killer (AK) cells by recombinant interleukin 2 (rIL 2) in collaboration with interferon-gamma (IFN-gamma)

Activation of human peripheral blood mononuclear cells (PBMC) by interleukin 2 (IL 2) and the role of interferon-gamma (IFN-gamma) in the IL 2-induced activation were investigated. Activated killer (AK) cells against NK-resistant tumor cell lines were induced in the medium containing recombinant IL 2 (rIL 2) and autologous serum without any other stimulating agents. AK activity was induced by doses of rIL 2 as low as 3 U/ml, and reached a maximum at 10(3) U/ml. Incubation of PBMC with rIL 2 resulted in IFN-gamma production and augmented NK activity after 1 day of culture, and in induction of AK cells and proliferative response after 2 days of culture. These results suggested that endogenous IFN-gamma was required for rIL 2-induction of AK cells and proliferative response. To prove this, PBMC were cultured with rIL 2 and rIFN-gamma or were pretreated with rIFN-gamma before culture with rIL 2. Both rIFN-gamma treatments of PBMC augmented rIL 2-induced AK activity and proliferative response. rIL 2-induced IFN-gamma production was also enhanced by the rIFN-gamma pretreatment of PBMC. The addition of anti-IFN-gamma antibody to rIL 2 cultures abrogated the rIL 2-induced NK augmentation, AK generation, and proliferative response in proportion to the decreased amounts of endogenous IFN-gamma detectable in culture. rIFN-gamma and/or rIL 2 cultures of PBMC increased Tac antigen expression on cell surfaces as measured by flow cytometry. Enhanced Tac expression by rIL 2 was abrogated by adding anti-IFN-gamma antibody. These data indicate that: 1) AK generation and IFN-gamma production are mediated by IL 2, and 2) IFN-gamma production may be required for IL 2 induction of AK cells and proliferative response. These finding are consistent with the hypothesis that AK generation involves a collaboration between IL 2 and IFN-gamma, in which IL 2 stimulates PBMC to produce IFN-gamma, which in turn acts as a differentiation signal that may be involved in the IL 2-initiated AK generation and proliferative response.     

X-ray crystallographic and chromatographic characterization of the crystals of Ca2+-calmodulin complexed with bee venom melittin

Crystals of calmodulin complexed with both Ca2+ and melittin, a peptide from bee venom, have been grown from 2-methyl-2,4-pentanediol solution by using the hanging drop method of vapour diffusion. The crystals belong to space group P2(1)2(1)2(1) with a = 97.3(9) A, b = 56.5(0) A, c = 33.4(9) A and Z = 4. Analyses of the dissolved crystals by high performance liquid chromatography show that the crystals contain a 1:1 complex of calmodulin and melittin. An asymmetric unit contains one such complex and the solvent content of the crystals is 47.5% (v/v).     

Gamma-MSH and its related peptides do not augment ACTH-induced steroidogenesis in isolated rat adrenal cells

In a sensitive ACTH bioassay system using isolated rat adrenal cells, we tested the effect of gamma-MSH related peptides on ACTH-induced steroidogenesis. Peptides, including synthetic gamma1-, gamma2-, gamma3- and Lys-gamma3-MSH, exerted no effect in augmenting ACTH-induced steroidogenesis. None of the 16 kilodalton fragment of ACTH/beta-lipotropin precursor and its cleaved fragment had such an activity. The results are in contrast with previous reports concerning ACTH-potentiating activity of gamma-MSH related peptides and, therefore, indicate the necessity of further investigation of the principle involved in this unique biological activity.     

Immigration of the brown planthopper, Nilaparvata lugens, exhibiting various responses to density in relation to wing morphism

Considerable inherent variations in the relation between macropterous and brachypterous wing forms, and nymphal density were found in field populations of the brown planthopper, Nilaparvata lugens Stål (Homoptera: Delphacidae), collected from various locations in Japan. When compared under uniform laboratory rearing conditions, most of the female populations exhibited higher ratios of macropters with increasing nymphal density, but some showed extremely high proportion of brachypters and the others were highly macropterous, over broad ranges of density. These results indicate the possibility that the planthoppers in Japan, which are known not to persist in winter, are derived from different migration sources.About ten generations of successive selection for brachyptery from a population showing usual density-dependent wing morphism generated populations similar to highly brachypterous ones mentioned above. Genetic analysis of the inheritance of wing morphism revealed that brachyptery in the females was controlled by a single pair of dominant alleles. However, in the males wing forms did not segregate so clearly in the crossing experiments. This suggests that wing morphism in N. lugens in under sex-limited inheritance.

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Einwanderung von Nilaparvata lugens mit unterscheidlicher Reaktion auf Populationsdischte bei der Flügelausbildung

Zusammenfassung In Feldpopulationen von Nilaparvata lugens Stål., welche in verschiedenen Regionen Japans gesammelt wurden, bestand in der Beziehung zwischen makropteren bzw. brachypteren Flügelformen und der Larvendichte eine beträchtliche Variation. Unter einheitlichen Zuchtbedingungen im Laboratorium stieg der Makropterenanteil bei den meisten Weibchenpopulationen mit steigender Temperatur; bei einigen Populationen hingegen war entweder der Brachypterenanteil oder der Makropterenanteil extrem hoch und zwar über weite Dichtebereiche. Dies deutet auf die Möglichkeit hin, dass die Zikade in Japan, wo sie bekanntlich nicht überwintert, jeweils aus verschiedenen Quellen einwandert.Wenn eine Population mit der üblichen dichteabhängigen Flügelausbildung 10 Generationen lang auf Brachypterie selektioniert wurde, entstanden Populationen, die den erwähnten hochbrachypteren Populationen aus dem Feld glichen. Die genetische Analyse der Vererbung der Brachypterie ergab, dass bei Weibchen ein einzelnes dominantes Allel verantwortlich ist. Bei Männchen dagegen trennten sich bei Kreuzungsexperimenten die Flügelformen nicht so klar. Dies deuted auf Unterschiede zwischen den Geschlechtern bei der Vererbung der Flügelformen.

     

Morphine-Induced Changes in Histamine Dynamics in Mouse Brain

The effect of the acute morphine treatment on histamine (HA) pools in the brain and the spinal cord was examined in mice. Morphine (1-50 mg/kg, s.c.) administered alone caused no significant change in the steady-state levels of HA and its major metabolite, tele-methylhistamine (t-MH), in the brain. However, depending on the doses tested, morphine significantly enhanced the pargyline (65 mg/kg, i.p.)-induced accumulation of t-MH and this effect was antagonized by naloxone. A specific inhibitor of histidine decarboxylase, alpha-fluoromethylhistidine (alpha-FMH) (50 mg/kg, i.p.), decreased the brain HA level in consequence of the almost complete depletion of the HA pool with a rapid turnover. Morphine further decreased the brain HA level in alpha-FMH-pretreated mice. Morphine administered alone significantly reduced the HA level in the spinal cord, an area where the turnover of HA is very slow. These results suggest that the acute morphine treatment increases the turnover of neuronal HA via opioid receptors, and this opiate also releases HA from a slowly turning over pool(s).