Baculovirus ACMNPV as well as RNA- and protein-synthesis inhibitors induce apoptosis in a continuous midgut cell line, FPMI-CF-203, of Choristonuera fumiferana (Lepitoptera: tortricidae)

Author(s):  
A.J. Brownwright ◽  
S.R. Palli ◽  
G.F. Caputo ◽  
S.S. Sohi

Apoptosis is an active cellular self-destruction regulated by expression or repression of certain genes. Apoptosis can be caused by a variety of both external and internal stimuli. Whether these different stimuli that can cause apoptosis converge into a final pathway that leads to self-destruction is not known. This paper compares apoptosis caused by a baculovirus, an RNA-synthesis inhibitor and a protein-synthesis inhibitor.Inoculation of IPLB-SF-21 (SF-21) and FPMI-CF-203 (CF-203, Fig. 1, ) cells with Autographa californica multicapsid nuclear polyhedrosis virus (AcMNPV) and Choristoneura fumiferana multicapsid nuclear polyhedrosis virus (CfMNPV), respectively, results in successful infection as visualized by formation of occlusion bodies (OBs). However, inoculation of CF-203 cells with AcMNPV, or SF-21 cells with CFMNPV, is unsuccessful and no OBs are seen. Inoculation of CF-203 cells with AcMNPV results in premature lysis of cells beginning at 12 hr post-inoculation (pi) and most of the cells are lysed by 48 hr pi.

1974 ◽  
Vol 62 (3) ◽  
pp. 707-716 ◽  
Author(s):  
Charles T. Roberts ◽  
Eduardo Orias

Tetrahymena is able to adapt to the presence of sublethal concentrations of many drugs which inhibit a wide variety of cellular functions. In spite of the generality of this phenomenon in Tetrahymena, the mechanism of adaptation at the cellular and molecular levels is unknown. This study deals mainly with adaptation to the protein synthesis inhibitors, cycloheximide and emetine. The physiological response of Tetrahymena to sublethal concentrations of these drugs is an immediate cessation of cell division for a period of time dependent on the drug concentration, followed by an abrupt resumption of exponential growth at a constant rate. By measuring the length of the growth lags under a variety of experimental conditions, we have confirmed several observations made by Frankel and coworkers, and provide evidence for two new phenomena associated with adaptation to cycloheximide: (a) adaptation to cycloheximide also results in adaptation of cells to emetine, another protein synthesis inhibitor not closely related structurally to cycloheximide. We have termed this phenomenon cross adaptation, (b) exposure to concentrations of cycloheximide too low to cause any growth lags or inhibition of protein synthesis significantly shortens the time required by cells to adapt to higher concentrations of cycloheximide. We have termed this phenomenon facilitation. Facilitation shows some degree of specificity in that facilitation with cycloheximide has no effect on adaptation to emetine. From this, we infer the existence of two distinct systems involved in adaptation to cycloheximide, one of which shows a higher degree of specificity towards cycloheximide than the other. We also show that transfer of adapted or facilitated cells to drug-free medium results in a gradual but complete resensitization. The kinetics of resensitization suggest that the cellular machinery responsible for adaptation and facilitation does not leave the cell, but is simply diluted out during cell division.


1971 ◽  
Vol 178 (1053) ◽  
pp. 455-464 ◽  

1. Memory in day-old-chickens during the first few hours after learning can be made to decline by the prior intracranial injection of two classes of drugs. 2. Sodium pump inhibitors in increasing doses cause increasingly rapid loss of memory. 3. Protein synthesis inhibitors in increasing doses attain a maximum potency in causing memory decline and the rate may not be further accelerated by higher doses. 4. Adding a sodium pump inhibitor to the inhibition of protein synthesis increases memory loss. 5. Adding a protein synthesis inhibitor to a sodium pump inhibitor causes no further loss. 6. Therefore within a few minutes of learning a short-term memory of limited time span but independent of protein synthesis becomes supplemented and eventually replaced by a long-term storage requiring protein synthesis. The amount of long-term store is set by the amount of short-term memory. 7. The short-term store could be directly dependent on post-activation enhancement of Na + extrusion from neurons. Some physiological mechanisms by which this could be achieved and how this might activate protein synthesis are discussed.


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