Abortive Infection of L Cells by Influenza B Virus: Defect in Bud Formation

Host-dependent restriction of influenza B virus replication in L cells was analysed in comparison with productive infection in MDCK or 1–5C-4 cells. The synthesis and intracellular distribution of virus-specific proteins and the production of cytoplasmic ribonucleoproteins in nonpermissive L cells were similar to those in permissive MDCK cells. However, an electron microscopic study of infected L cells showed neither extracellular virions nor budding virus particles on the cell surface, in contrast to MDCK cells which produced numerous virus particles. PAGE analysis of the plasma membrane isolated from the cells demonstrated no significant difference in the composition of viral polypeptides between permissive 1-5C-4 and nonpermissive L cells. It was noted that the abortiveness of influenza B virus infection in L cells may be due to a defect in host cell function involved in the initiation of virus budding.     

Dynamic light-scattering study of semiflexible polymers: collagen

Dynamic light-scattering measurements were carried out for collagen in acetate buffer (pH 4.8) extracted from lathyritic ratskin. The correlation functions were analyzed in terms of the semiflexibility of collagen molecules. The experimental Γ /K² vs K² relationship was compared with the theoretical one based on formulation including anisotropy in translational diffusion, chain flexibility, and the hydrodynamic interaction; Γ is the average decay rate and K is the magnitude of the momentum transfer vector. By using the model parameters evaluated from the Γ /K² vs K² relationship, a good agreement was obtained between profiles of theoretical and experimental correlation functions over the entire delay times. Detailed examinations of the dynamic light-scattering spectrum permitted us to conclude that a set of the contour length L of 300 nm and the Kuhn length γ^?1 of 340 nm are much more probable than other sets of L and γ^?1 that equally explain static quantities such as the radius of gyration. The results show that collagen molecules are well characterized by a wormlike chain model.     

Clerodane diterpenoids from the roots of Portulaca pilosa

Three trans-clerodane diterpenoids, pilosanol A, B and C, the last compound being a glucoside, have been isolated from the roots of Portulaca pilosa. They show a marked contrast in skeletal type with the constituents of aerial part. Evolutionary changes in the biosynthetic abilities of Portulaca species is discussed.     

Effects of cytokines on in vitro growth of tumor-infiltrating lymphocytes obtained from human primary and metastatic liver tumors

Summary Tumor-infiltrating lymphocytes (TIL) were isolated from 22 human primary and metastatic liver tumors, and expanded in vitro in the presence of either interleukin-2 (IL-2, 100 U/ml) plus tumor necrosis factor (TNF, 1000 U/ml), IL-2 (1000 U/ml) plus IL-4 (1000 U/ml) or IL-2 (1000 U/ml) alone. TIL proliferated in culture in 20/22 cases. Among different cytokine combinations, TNF and IL-2 were most effective in promoting the outgrowth of CD3⁺ CD8⁺ T lymphocytes (mean ± SEM: 90%±5) in the cultures of TIL from primary liver tumors. Cytotoxicity against autologous tumor cells was demonstrated in all early cultures of TIL from primary liver cancers in the presence of IL-2 plus TNF. In contrast, cultures of TIL derived from colon cancer metastatic to liver had significantly lower levels of autotumor cytotoxicity and proportions of CD3⁺ CD8⁺ cells (40%±13) than those of TIL from primary liver tumors. The addition on day 0 of interferons ( or ) to TIL cultured in the presence of TNF and IL-2, significantly augmented cytotoxicity against autologous tumor. In contrast, incubation of TIL in the presence of IL-4 and IL-2 did not result in increased autotumor responses in the cultures of TIL from primary liver tumors. The expansion (-fold) of TIL (day 30) cultured in the presence of IL-2 alone compared to that in the presence of TNF and IL-2 was significantly greater for hepatocellular carcinoma (median, 280 vs 260) than for autologous peripheral blood lymphocytes (36 vs 27), cholangiocarcinoma (42 vs 51) or TIL from metastatic colon cancer (39 vs 30). Outgrowth of TIL in IL-2 plus TNF offers an opportunity for in vitro enrichment in cells with autotumor cytotoxicity in primary liver tumors. However, this cytokine combination was unable to promote and sustain growth of autotumor effectors from TIL in metastatic liver cancer.Supported by ACS grants IM27 077 and IM588 A (TLW) and Organ Transplant Program Project 1P01-CA-4744501 AZ     

Dynamic light scattering from polydisperse suspensions of large spheres. Characterization of isolated secretory granules.

Dynamic light scattering is useful in determining the diameter of submicrometer particles in suspension. When both static scattering intensity P(K) and apparent diffusion coefficient D can be measured in a wide range of the length of the scattering vector K, it is possible to determine the number-average diameter dn and sharpness in size distribution of spheres. We derived approximate, but very simple, expressions for mean value of P(K) and mean value of D/D(dn) applicable to very large spheres for which the so-called Rayleigh-Debye condition is perturbed, where mean value of ... stands for the size average. These approximate expressions were compared with the numerical results based on the Mie scattering theory. Experimental results for isolated secretory granules, zymogen (dn approximately 800 nm) and chromaffin (dn approximately 400 nm) granules, were analyzed by use of the present formulation, and the dispersion in size distribution, sigma/dn = [(the mean of d2)/d2n - 1]1/2, was found to be about 0.2 for both types of granules.     

Growth and Aspartate Kinase Activity in Wheat Cell Suspension Culture: Effects of Lysine Analogs and Aspartate-Derived Amino Acids

The effects of lysine analogs and aspartate-derived amino acidson the growth of wheat cell suspension culture were studied.S-(2-Aminoethyl)-L-cysteine (AEC), -hydroxylysine (DHL) andtrans-lysene caused complete growth inhibition at 1.0 mM. Thegrowth inhibition of lysine analogs were, in the order of decreasingeffectiveness; AECDHL, trans-lysene>oxalysine, homolysineand lysyne. cis-Lysene and methyllysine were not inhibitoryeven at concentrations of 10 mM. Lysine effectively relievedgrowth inhibition induced by the lysine analogs. Lysine plusthreonine showed concerted inhibition, which was relieved bythe addition of methionine. Activity of aspartate kinase extracted from wheat cell suspensionculture was strongly inhibited by L-lysine; 0.75 to 1 mM oflysine was required for half-maximal inhibition. Threonine andmethionine, individually or in combination with lysine, showedno inhibitory effect on the enzyme activity. S-Adenosylmethionine,when added with lysine in equimolar concentrations, enhancedthe feedback inhibition by lysine, lowering the concentrationof lysine for half-maximal inhibition to 0.13 mM. The aspartatekinase isolated from the cells cultured in the presence of 5mM lysine did not differ in regulatory properties from the enzymefrom the cells cultured without lysine. AEC at 5 mM inhibitedthe enzyme activity by 50%. Other lysine analogs were not inhibitoryto the enzyme activity even at 10 mM. Growth inhibition of wheat suspension culture by aspartate-derivedamino acids and lysine analogs were discussed in relation totheir inhibitory effects on aspartate kinase activity. (Received October 25, 1985; Accepted February 26, 1986)     

Dynamic light scattering study of suspensions of purple membrane

Purple membrane from Halobacterium halobium in suspensions has been studied by quasielastic light scattering. The intensity correlation functions of polarized scattered light were measured at various K2 values (K being the magnitude of the scattering vector), and the first cumulant Gamma of the field correlation function G1(tau) was obtained by a cumulant expansion method. The apparent diffusion coefficient Gamma /K2 did not increase monotonically with K2 values and showed a distinct anomaly in an intermediate range of K. A theoretical formulation of G1(tau) for a disc and an extremely oblate ellipsoidal shell of revolution (S. Fujime and K. Kubota, Biophys. Chem. 23 (1985) 1) was applied to the analysis of the spectra, and characteristic features of experimental spectra were well reproduced. It was suggested that a strong interference effect between scattered rays on Gamma /K2 should be attributed to a slight noncircular shape of the purple membrane and that a contribution to Gamma /K2 from membrane flexibility should be taken into account. This study will provide experimental evidence of the feasibility of membrane studies by dynamic light scattering.     

False positive reaction for carcinoembryonic antigen in paget cells

Virchows Archiv B Cell Pathology - Paget cells from cases of mammary and extramammary Paget’s disease were examined for carcinoembryonic antigen (CEA) and CEA-related antigens by the...     

Dynamic light-scattering study on polymerization process of muscle actin

Globular actin (G-actin) polymerizes into a fibrous form (F-actin) under physiological salt conditions. The polymerization process of muscle actin was studied by a dynamic light-scattering method. The intensity correlation functions G2(tau) of scattered light from a G-actin solution containing 2 mM Tris-HCl (pH 8.0) and 0.1 mM ATP were analyzed by a cumulant expansion method, and the translational diffusion coefficient was determined to be D = (8.07 +/- 0.10) X 10(-7) cm2/s at 20 degrees C. This D value gave a diameter of 5.3 nm for spherical G-actin including a hydration layer. Polymerization of 1-3 mg/ml G-actin in a solution containing 10 mM Tris-HCl (pH 8.0), 0.2 mM ATP and 60 mM KCl was followed by successive measurements of G2(tau) for a data accumulation period of 60-300 s/run. The time evolution of G2(tau) was analyzed by a least-squares fitting to the field correlation function of a multiexponential form g1(tau) = sigma iAi exp(-gamma i tau) with gamma 1 greater than gamma 2 greater than 3 greater than ..., and the static scattering intensity I(t) = mean value of I as a function of time t after initiation of polymerization was decomposed as I(t) = mean value of I sigma iAi. At the early stage of polymerization, a two-exponential fit gave results indicating that component 1 came from G-actin and component 2 from F-actin growing linearly with t. At the middle stage of polymerization, a three-exponential fit gave the results that component 1 came from G-actin and possibly its small oligomers, component 2 from polymers with a number-average length Ln of about 900 nm which was independent of t, and component 3 from 'ghosts' in dynamic light scattering in a semidilute regime. Component 3 was concluded to arise from restricted motions of polymers with lengths much longer than Ln in cages formed by polymers giving component 2, and a fragmentation-elongation process of F-actin was suggested to start at the middle stage of polymerization, resulting in the size redistribution of F-actin.