Establishment and characterization of human neuroblastoma cell line (HSNB)

We cultured an aspiration fluid of the sternal bone marrow of the patient having adrenal neuroblastoma and established a neuroblastoma cell line (HSNB). The HSNB line has the following biological properties. 1. They are small round in shape and proliferate in flotation while forming cell aggregate, and often they attach the bottom of plastic dish and process the nerve-like fibers. A rough-endoplasmic reticulum are poorly developed, however, a lot of free ribosomes are scattered in the cytoplasm. In the peripheral area of the cells, small spherical secretory granules (60-140 nm in diameter) are existed. One characteristic of this cell is existence of microtubules in the cell-projections. 2. They show a stable growth and the doubling time is about 50 hours. 3. Their chromosome number varied widely and the mode is 46. The double minute chromosomes were present in 50% of cells. 4. When they are transplanted in the cheek pouch of hamster, they produced the neuroblastoma. 5. They produce neuron specific enolase. 6. N-myc gene was amplified ca 250 folds.     

Melting from both ends of an A-band in a myofibril. Observation with a phase-contrast microscope

Observation with a phase-contrast microscope clearly shows that melting of an A-band, i.e., a bundle of thick (myosin) filaments, in a rabbit skeletal myofibril occurs from both ends in the pressure of high concentrations of KCl and PPi. Thick filaments partially melted from both ends can be obtained in a myofibril.     

Development of infant common marmosets’ (<Emphasis Type=Italic>Callithrix jacchus</Emphasis>) preference for their parents over adults from another group

Parent–offspring attachment is important for animals which have offspring that require parental care for their development. Infant attachment to the mother has been examined in macaques, but it remains poorly understood in common marmosets. Here, we examined the abilities of 14 common marmoset infants to show preference for their parents over adults from another group at the ages of 4, 10, and 15 weeks. Each infant was exposed to its parent and an adult from another group in an I-shaped maze. Although 4-week-old infants did not show a significant difference between approach behaviors toward their parents and other adults, 10- and 15-week-old infants approached and stayed longer near their parents than adults from another group. These results suggest selective approach behavior develops in marmosets by the age of 10 weeks.     

Observations on Aulacoseira nipponica from Lake Biwa, Japan, and Aulacoseira solida from North America (Bacillariophyceae)

A recent diatom, Aulacoseira nipponica (Skvortzow) Tuji comb. et stat. nov., is described from Lake Biwa, Japan, where they had been identified previously as Aulacoseira solida (Eulenstein) Krammer. These forms are compared with populations of A. solida from North America. The Japanese species differs from the North American specimens in characteristics related to the density of striae and form of the rimoportulae.     

Role of the Actin Ala-108–Pro-112 Loop in Actin Polymerization and ATPase Activities

Actin plays fundamental roles in a variety of cell functions in eukaryotic cells. The polymerization-depolymerization cycle, between monomeric G-actin and fibrous F-actin, drives essential cell processes. Recently, we proposed the atomic model for the F-actin structure and found that actin was in the twisted form in the monomer and in the untwisted form in the filament. To understand how the polymerization process is regulated (Caspar, D. L. (1991) Curr. Biol. 1, 30–32), we need to know further details about the transition from the twisted to the untwisted form. For this purpose, we focused our attention on the Ala-108–Pro-112 loop, which must play crucial roles in the transition, and analyzed the consequences of the amino acid replacements on the polymerization process. As compared with the wild type, the polymerization of P109A was accelerated in both the nucleation and the elongation steps, and this was attributed to an increase in the frequency factor of the Arrhenius equation. The multiple conformations allowed by the substitution presumably resulted in the effective formation of the collision complex, thus accelerating polymerization. On the other hand, the A108G mutation reduced the rates of both nucleation and elongation due to an increase in the activation energy. In the cases of polymerization acceleration and deceleration, each functional aberration is attributed to a distinct elementary process. The rigidity of the loop, which mediates neither too strong nor too weak interactions between subdomains 1 and 3, might play crucial roles in actin polymerization.     

Coordinated accumulation of the chloroplastic and cytosolic pyruvate,Pi dikinases with enhanced expression of CAM in Kalanchoë blossfeldiana

Recent studies reveal that the intracellular localization of pyruvate,Pi dikinase (PPDK, EC 2.7.9.1) in mesophyll cells of malic enzyme (ME)-dependent Crassulacean acid metabolism (CAM) plants varies among species, occurring not only in the chloroplasts but also in the cytosol in some species. The facultative CAM plant Kalanchoë blossfeldiana accumulates PPDK in both compartments of the mesophyll cells. In this study, the patterns of accumulation of the chloroplastic and cytosolic PPDKs were investigated for K. blossfeldiana plants with different CAM activities by immunogold labeling and electron microscopy. Greater CAM activity was found in plants grown under drought conditions with short days than under well-watered conditions with long days, and in lower leaves than in higher leaves. There was a trend that plants and leaves with greater CAM activity show denser labeling for PPDK in both the cytosol and chloroplasts. However, the ratio of the density of PPDK labeling in the cytosol to that in the chloroplasts was almost constant (2.4–3.0). Higher labeling for phosphoenolpyruvate carboxylase (EC 4.1.1.31) in the cytosol was also correlated with higher CAM activity but there was almost no difference in the density of labeling for ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) in the chloroplasts. These results indicate that the increase in accumulation of cytosolic PPDK is closely associated with the increase of chloroplastic PPDK during enhanced CAM expression. This suggests that both PPDKs are involved in CAM function.     

Cutting edge: VacA, a vacuolating cytotoxin of Helicobacter pylori, directly activates mast cells for migration and production of proinflammatory cytokines

Mucosal mast cells strategically located at the optimal site interact with invading bacteria. Presence of VacA, the virulent Helicobacter pylori cytotoxin, is correlated with the severity of H. pylori-induced gastritis. To examine the mechanisms of inflammation in H. pylori-induced gastritis, we administered VacA to the mice. Inoculation of VacA resulted in epithelium vacuolization and marked infiltrations of mast cells and mononuclear cells into the mucosal epithelium within 24 h. In an in vitro study using bone marrow-derived mast cells, VacA directly bound and showed a chemotactic activity to the mast cell. In addition, VacA induced bone marrow-derived mast cells to produce proinflammatory cytokines, TNF-alpha, macrophage-inflammatory protein-1alpha, IL-1beta, IL-6, IL-10, and IL-13 in a dose-dependent manner without causing degranulation. The present study suggests that early activation of mast cells by VacA may be the host early response to clear the bacteria and also may contribute to the pathogenesis of H. pylori-induced gastritis.     

Protein kinase C-associated kinase (PKK) mediates Bcl10-independent NF-kappa B activation induced by phorbol ester

Protein kinase C-associated kinase (PKK) is a recently described kinase of unknown function that was identified on the basis of its specific interaction with PKC beta. PKK contains N-terminal kinase and C-terminal ankyrin repeats domains linked to an intermediate region. Here we report that the kinase domain of PKK is highly homologous to that of two mediators of nuclear factor-kappa B (NF-kappa B) activation, RICK and RIP, but these related kinases have different C-terminal domains for binding to upstream factors. We find that expression of PKK, like RICK and RIP, induces NF-kappa B activation. Mutational analysis revealed that the kinase domain of PKK is essential for NF-kappa B activation, whereas replacement of serine residues in the putative activation loop did not affect the ability of PKK to activate NF-kappa B. A catalytic inactive PKK mutant inhibited NF-kappa B activation induced by phorbol ester and Ca(2+)-ionophore, but it did not block that mediated by tumor necrosis factor alpha, interleukin-1 beta, or Nod1. Inhibition of NF-kappa B activation by dominant negative PKK was reverted by co-expression of PKC beta I, suggesting a functional association between PKK and PKC beta I. PKK-mediated NF-kappa B activation required IKK alpha and IKK beta but not IKK gamma, the regulatory subunit of the IKK complex. Moreover, NF-kappa B activation induced by PKK was not inhibited by dominant negative Bimp1 and proceeded in the absence of Bcl10, two components of a recently described PKC signaling pathway. These results suggest that PKK is a member of the RICK/RIP family of kinases, which is involved in a PKC-activated NF-kappa B signaling pathway that is independent of Bcl10 and IKK gamma.