The apparent infection of NA-C1300 cell cultures by nucleocapsid material of the Canadian Arctic strain of rabies virus

1989 ◽  
Vol 35 (8) ◽  
pp. 811-813
Author(s):  
W. A. Webster ◽  
K. M. Charlton

Murine neuroblastoma (NA-C1300) and baby hamster kidney (BHK-21/C13) cell cultures were infected with the Canadian Arctic strain of rabies virus. Subcultures were passed following incubation for 3 to 4 days at 35 °C. The supernatant fluids from the BHK cultures demonstrated increasing infectivity in both NA and BHK cells concomitantly with an increase in the number of parent cells staining with an anti-glycoprotein stain. On the other hand, the supernatant fluids from the NA cultures initially showed higher infectivity in NA cells than in BHK cells. This feature was related to a low production of glycoprotein-staining cells in the parent NA cultures. The reduction of infectivity in NA cells of some NA supernatant fluids (and brain suspensions) by anti-nucleoprotein antibodies suggests that nucleocapsid material is, in some manner, capable of infecting NA cells. Infectivity of this virus strain in experimental mice is also related to the production of glycoprotein and may not be correlated with the degree of infection in NA cell cultures.Key words: rabies, nucleocapsid, infection, cells.

1988 ◽  
Vol 90 (2) ◽  
pp. 201-214 ◽  
Author(s):  
F. Grinnell ◽  
C.H. Ho ◽  
T.L. Tuan

In this report we describe cell adhesion and phagocytosis promoted by two monoclonal antibodies that were selected for immunofluorescence staining of non-permeabilized baby hamster kidney (BHK) cells. Anti-BHK1 staining was heaviest along cell margins, whereas anti-BHK2 staining was continuous along cell margins. Neither antibody stained elongated plaque structures such as were observed when cells were reacted with antibodies to fibronectin (FN) receptors. The monoclonal antibodies functioned as adhesion ligands in four different assays: attachment to culture dishes, spreading, binding of latex beads and phagocytosis. Anti-BHK1 and anti-BHK2 promoted attachment to culture dishes similarly, but anti-BHK2 was more effective at promoting cell spreading. Antibody-promoted cell spreading was inhibited by the peptides Ser-Asp-Gly-Arg and Gly-Arg-Gly-Asp-Ser-Pro but not by other, related, peptides tested. The monoclonal antibodies also promoted binding of latex beads, and the bead binding sites were motile, on the basis of their ‘capping’ response. Nevertheless, anti-BHK2 beads were phagocytosed by cells 5- to 20-fold more efficiently than anti-BHK1 beads. The binding sites for anti-BHK1 and anti-BHK2 were characterized by immunoprecipitation experiments. Anti-BHK1 binding sites contained 50K (K = 10(3) Mr) and 88K components under non-reducing conditions that migrated as a 51/53K doublet and a 93K component under reducing conditions. On the other hand, anti-BHK2 binding sites contained 88K and 110K components under non-reducing conditions that shifted to apparent 107K and 128K values when measured under reducing conditions.


Intervirology ◽  
1978 ◽  
Vol 9 (6) ◽  
pp. 359-361 ◽  
Author(s):  
Abigail L. Smith ◽  
Gregory H. Tignor ◽  
Richard W. Emmons ◽  
James D. Woodie

Author(s):  
Rosana Mary Sartor ◽  
Paulo Mazzafera

The low caffeine content in leaves of C. dewevrei (~ 0.5 mg/g) is due to a low biosynthesis associated with a fast degradation. On the other hand, high biosynthesis and low degradation confer a higher content (~ 8 mg/g) in leaves of C. arabica. In this work it was observed that cell cultures of C. dewevrei recovered the ability to synthesize caffeine almost in similar levels of C. arabica cultures. Tracer experiments with labelled carbon dioxide showed a significant accumulation of radioactivity in caffeine and metabolites, indicating an active biosynthesis. When the cultures were fed with labelled caffeine most of the radioactivity was recovered in caffeine, indicating that although active, degradation was not so efficient as in leaves, and therefore, contributing for the alkaloid accumulation in the cell cultures.


1985 ◽  
Vol 101 (2) ◽  
pp. 386-394 ◽  
Author(s):  
K Nagata ◽  
M J Humphries ◽  
K Olden ◽  
K M Yamada

We have examined the effects of soluble collagen on the function of fibronectin in baby hamster kidney (BHK) cells. Collagen and its purified alpha1(l) chain noncompetitively inhibited cell spreading on substrates precoated with fibronectin or a 75,000-D cell-binding fragment of fibronectin. Neither preincubation of cells with collagen followed by washing nor the addition of collagen to previously spread cells had any inhibitory effect on cell spreading, which indicates a requirement for the concurrent presence of collagen during the process of spreading. Treatment of collagen or alpha1(l) chain with collagenase abolished the inhibitory effect on fibronectin-mediated cell spreading. However, direct attachment of BHK cells to fibronectin-coated or 75,000-D fragment-coated substrates was not inhibited by collagen or by the alpha1(l) chain. Moreover, the binding of [3H]fibronectin or the 3'-75,000-D fragment to cell surfaces was not inhibited by the presence of soluble collagen, whereas soluble fibronectin inhibited binding. Although the binding of [3H]fibronectin-coated beads to BHK cell surfaces was also not inhibited by collagen, the phagocytosis of such beads was inhibited by the presence of collagen. On the other hand, soluble fibronectin partially inhibited the binding of fibronectin-coated beads but did not inhibit phagocytosis of the beads that did bind. The mechanism of the inhibition of fibronectin function by collagen and the possible interactions of two different kinds of receptors on the cell surface are discussed.


1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.


Author(s):  
A. V. Crewe

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.


Author(s):  
K.H. Westmacott

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.


2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


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