Electrodermal reactions to opposite types of autogenic training imagery

An experiment was conducted to determine the effects of autogenic and ‘opposite autogenic’ verbal formulae upon electrodermal activity. In a between-subjects design, 15 unpracticed volunteers listened to and followed tape recorded imagery suggestions for relaxation and quietude, heaviness and warmth in the extremities, warmth in the central area of the body, coolness of the forehead, and calmness and regularity of breathing and circulation; 15 additional volunteers were exposed to opposite suggestions. Frequency of spontaneous GSRs, cumulative peak amplitude of spontaneous GSRs, and basal skin resistance levels were measured during 2 min epochs before and after the suggestions. Directionally appropriate changes occurred in all three electrodermal measures; these changes were significant for the two GSR measures and approached significance for the BSR measure. The autogenic suggestions produced greater and more reliable visceral effects than did the ‘opposite autogenic’ suggestions.     

RNA polymerase from tobacco necrosis virus-infected and uninfected tobacco: II. Properties of the bound and soluble polymerases and the nature of their products

RNA polymerase activities in extracts of healthy and tobacco necrosis virus (TNV)-infected tobacco plants were investigated. Considerable ”bound“ enzyme activity, associated with endogenous viral RNA template, was found in the 30,000 g pellet obtained from TNV-infected plants. This activity was usually not increased by addition of RNA. In the corresponding fraction from healthy plants a much lower activity was detected which was increased when RNA was added. The conditions favoring the enzyme activity and its general properties were investigated. The RNA synthesized by this enzyme on the endogenous template, be it in the particulate state or solubilized and ammonium sulfate-fractionated, was about 90% double-stranded and of high molecular weight. It corresponds to a viral plus strand. After melting, this RNA comigrated with TNV-RNA. Thus it appears that the membrane-bound enzyme in TNV-infected plants represents a TNV replicase which is able to synthesize or finish full-length TNV-RNA on an endogenous template, the minus strand of TNV-RNA; this enzyme-template complex can be solubilized and fractionated without losing this ability. Nucleotide polymerizing activity was also detected in the 100,000 g supernatant of healthy tobacco plants and this activity was significantly increased upon TNV infection. This activity which resembled in some respects that reported by Duda et al. (1973) was greatly stimulated by added RNA. The products synthesized by this “soluble” enzyme extracted from healthy and infected plants were of similarly low molecular weight; they consisted of both single- and doubles-tranded RNAs and behaved partly as expected for fragments of minus-strand viral RNA.     

Tumorigenicity of adenovirus-transformed rat cells and expression of class I major histocompatibility antigen

The expression of class I major histocompatibility antigens was studied in six syngeneic adenovirus 12 (Ad12)-transformed LIS rat cell lines of varying tumorigenicity. The concentration of MHC class I product was estimated by indirect immunofluorescence staining of viable cells in suspension with specific antibody and cytofluorographic analysis, and by sensitivity to killing by allogeneic cytolytic T cells (CTLs) elicited by immunization with spleen cells in vivo and in mixed lymphocyte reactions in vitro. None of the rat cell lines examined was devoid of MHC class I antigen. When compared to syngeneic Ad2-transformed cells or fibroblasts, the average intensity of fluorescence of Ad12-transformed lines was lower, suggesting that the concentration of MHC class I antigen is somewhat lower in Ad12-transformed cells. Sensitivity to killing by both in vivo and in vitro induced allogeneic CTLs, however, was not markedly lower with Ad12-transformed cells and correlation was not found between tumorigenic potential in vivo and sensitivity to allogeneic T-cell killing in vitro.     

Endogenous mouse type-C RNA virus of SWR cells: Inducibility locus containing structural information for a new endogenous virus class

A type-C RNA virus with a host range preference for BALB/c mouse embryo cells is chemically inducible from embryo cells of the inbred SWR strain. The SWR virus is shown to be readily distinguishable from previously identified endogenous viruses of mouse cells by nucleotide sequence homology analysis. A single dominant gene for SWR virus inducibility is shown to segregate in crosses involving the inducible SWR and non-virus-inducible NIH Swiss strains. Moreover, nucleotide sequences specific for the SWR virus are demonstrated to be present only in cellular DNAs of SWR virus-inducible embryo lines. These findings establish that the SWR inducibility locus contains structural information of this virus.     

Isolation and characterization of a slow-migrating class of adenovirus type 2 hexons.

A special class of Adenovirus type 2 hexons, similar in shape and morphology to normal hexons but differing from them in electric charge have been isolated and biochemically and immunologically characterized. These aberrant hexons were reminiscent of slow-migrating hexons previously found (Pettersson, 1971). The “slow” hexons had a lower electrophoretic mobility, a higher isoelectric point, and a greater type-specific antigenicity than the normal hexons. They were constituted of a trimeric arrangement of polypeptide subunits of molecular weight 115,000 and thus formed of an amino acid sequence shorter than that of normal hexons by 50–60 amino acid residues. The N-terminal-end of their polypeptide subunit was not blocked by acetylation, as in normal hexons, suggesting that proteolytic cleavage occurred at the N-terminus. These slow hexons were not found in the adenovirus capsid and the possible mechanism of their occurrence is discussed.     

Quantitation of the relatedness of reovirus serotypes 1, 2, and 3 at the gene level

As judged by the ability of their genomes to hybridize, reovirus serotypes 1 and 3 are related to the extent of about 70% to each other and about 10% to serotype 2. Two techniques were developed to measure the extent to which the individual cognate genes of these serotypes are related. Both involve comparison of heterologous hybrid genes that contain plus and minus strands of genes of different serotypes with homologous hybrid genes (molecules formed by reannealing the separated plus and minus strands of the same gene). In the first technique, the amounts in such hybrids of material sensitive to ribonuclease under standard conditions were compared; in the second, their relative electrophoretic mobilities. The results obtained with the two techniques agreed well. They showed that for the three reovirus isolates examined (the Lang strain of serotype 1, the D5 Jones strain of serotype 2, and the Dearing strain of serotype 3), all 10 genes of serotypes 1 and 3 are much more closely related to each other than to the genes of serotype 2. Although this result relates to only three isolates of mammalian reovirus, it suggests that the gene sets of reovirus serotypes 1, 2, and 3 evolved independently of each other. Apparently double infection of hosts with strains of two reovirus serotypes, which would very likely yield recombinants, occurs infrequently and/or such recombinants have a lower survival advantage than strains containing “pure” gene sets. The results also show that the gene that has diverged most markedly during evolution is the S1 gene, the gene that encodes the minor outer shell capsid protein σ1 which is the reovirus cell attachment protein and hemagglutinin and possesses the most type-specific antigenic determinants. The serotype 1 and 3 S1 genes are about 10% homologous, serotype 2 and serotype 1 or 3 S1 genes about 3%. The genes that have diverged least are the three L genes (85–90% homology for the serotype 1 and 3 L genes). In all cases, the serotype 2 and serotype 1 or 3 genes exhibit no more than 20%, and often less than 10% homology. In spite of this high degree of divergence, the antigenic determinants on proteins encoded by genes of serotype 2 on the one hand and serotypes 1 and 3 on the other hand are, with the exception of those on proteins σ1, highly conserved, and the 60 to 80 nucleotides at the 5′- and 3′-termini of at least three sets of cognate genes (L3, M3, and S2) of all three serotypes, serotype 1 and 3 as well as serotype 2, are highly homologous and in some instances almost identical. Thus, while some regions of reovirus genes have diverged greatly during evolution, others have been highly conserved.     

Effect of bovine parvovirus replication on DNA,RNA, and protein synthesis in S phase cells

The kinetics of replication of bovine parvovirus (BPV) and the effect of viral replication on cellular macromolecular synthesis were examined in hydroxyurea (HU)-synchronized fetal bovine spleen cells. Immediately after release of cells from HU block, 80–85% of the cells began to synthesize DNA. The production of infectious progeny BPV proceeded at a faster rate in synchronized cells infected at the beginning of S phase than in asynchronous cultures. In synchronized cells, titers of infectious virus increased at 8 hr p.i. and the maximum titer was achieved by 20 hr. BPV DNA synthesis preceded the production of progeny virus by 2 hr. Although the rates of RNA and protein synthesis in infected cells were severely reduced after 8 hr p.i., BPV replication did not affect the rate of progression of cells through S phase.     

The timing of erf-mediated recombination in replication, lysogenization, and the formation of recombinant progeny by Salmonella phage P22.

Following infection, the development of phage P22 by either the lytic or the lysogenic pathways requires recombination, mediated either by the phage erf system or by the bacterial rec system [Botstein, D., and Matz, M. J. (1970) J. Mol. Biol. 54, 417–440]. We have investigated the timing of the essential recombinational processes with temperature-shift experiments using a temperature-sensitive erf mutant. In rec^? cells, erf function appears to be required early in the infection to complete some essential step, the timing of which is the same in both the lytic and lysogenic circumstances. Once the step has taken place, subsequent development can occur without further erf function. However, the bulk of recombinant progeny arising in lytic crosses in rec^? cells result from nonessential erf action late in the infection, after the time of the required early step.     

Biosynthesis of reovirus-specified polypeptides. Multiplication rate but not yield of reovirus serotypes 1 and 3 correlates with the level of virus-mediated inhibition of cellular protein synthesis

Kinetic analysis of mouse L fibroblast cells infected with reovirus revealed that serotypes 1 (Lang strain) and 3 (Dearing strain) differ significantly from each other in terms of their rates of multiplication and their effects on cellular protein synthesis. Serotype 1 did not significantly affect the synthesis of cellular polypeptides in monolayer cultures of L cells at late times after infection when virus-specific protein synthesis was at a maximum. By contrast, under identical culture conditions, serotype 3 essentially completely inhibited the synthesis of cellular polypeptides at late times when viral protein synthesis was at a maximum. The kinetics of virus-specific polypeptide synthesis and the production of infectious progeny were considerably slower for the serotype 1 Lang strain as compared to the serotype 3 Dearing strain, both at 30 and 37 degrees. However, the relative pattern of viral polypeptide synthesis and the final yield of infectious progeny did not differ significantly between serotypes 1 and 3. For both serotypes, the maximum yield of infectious progeny was obtained shortly after the maximum rate of viral polypeptide synthesis was reached. These results suggest that the rate of multiplication, but not the final yield, of reovirus serotypes 1 and 3 is related to the extent of virus-mediated inhibition of cellular protein synthesis.     

Mechanism of interferon action. Kinetics of interferon action in mouse L929 cells: translation inhibition, protein phosphorylation, and messenger RNA methylation and degradation

The effect of the duration of interferon treatment of mouse L929 fibroblasts on the expression of ribosome-associated and cell-sap-localized translation inhibition, protein phosphorylation, and messenger RNA (mRNA) methylation and degradation was investigated. The following results were obtained: (1) Ribosomal salt-wash fractions prepared from L929 cells treated for 12 or 18 hr significantly inhibited the translation of methylated reovirus mRNA catalyzed by the cell-free system prepared from untreated ascites tumor cells. The translation of reovirus mRNA was slightly stimulated by the ribosomal salt-wash fractions prepared from untreated cells and cells treated for 2 hr and was slightly inhibited by the salt-wash fraction from cells treated for 6 hr. (2) Cell-sap fractions prepared from untreated cells and from cells treated for 2 or 6 hr did not appreciably affect the translation of reovirus mRNA in the absence of double-stranded RNA (dsRNA); cell-sap fractions prepared from cells treated for 12 or 18 hr were slightly inhibitory. (3) Neither reovirus genome dsRNA nor polyriboinosinic acid-polyribocytidylic acid inhibited the translation of reovirus mRNA by the untreated ascites system. The inhibitory activity of ribosomal salt-wash fractions from interferon-treated cells was dsRNA independent, whereas dsRNA enhanced the inhibitory activity of cell-sap fractions from interferon-treated cells. (4) Interferon treatment significantly enhanced a cell-sap-independent phosphorylation of at least three proteins present in the ribosomal salt-wash fractions. Phosphorylation of an approximately 50,000-dalton component was maximally enhanced after 12 hr of interferon treatment and was increased by dsRNA; phosphorylation of 30,000- and <20,000-dalton components was enhanced earlier and was dsRNA independent. (5) An increase in the nuclease-mediated degradation of [3H]uridine-labeled methylated reovirus mRNA catalyzed by ribosomal salt-wash fractions was detectable after 6 hr of interferon treatment and was maximally enhanced after 12 hr of interferon treatment to about threefold the level of the untreated ribosomal salt-wash fraction. The degradation was not enhanced by dsRNA. The levels of reovirus mRNA degradation catalyzed by cell-sap fractions from untreated cells and from cells treated with interferon for 2 to 18 hr were comparable. (6) No significant difference was observed in the ability of cell-sap fractions from untreated cells or from cells treated with interferon for 2 to 18 hr to catalyze the methylation of unmethylated reovirus mRNA. In addition, none of the ribosomal salt-wash fractions significantly inhibited reovirus mRNA methylation catalyzed by untreated ascites cell-free extracts. These results suggest that interferon treatment may mediate multiple biochemical changes in murine cells, including the specific phosphorylation of protein(s) associated with ribosomes that possess interferon-mediated inhibitor(s) of viral mRNA translation.     

Effect of tunicamycin and monensin on biosynthesis, transport, and maturation of bovine herpesvirus type-1 glycoproteins

The effect of tunicamycin and monensin on the biosynthesis, intracellular transport, and maturation of bovine herpesvirus type-1 (BHV-1) glycoproteins was examined. Tunicamycin completely inhibited the production of infectious virus particles and significantly reduced the incorporation of [3H]glucosamine into viral glycoproteins. In the presence of monensin, reduced amounts of infectious virus particles were produced, which was mainly due to inhibition of virus release, rather than virus production. Monensin only slightly inhibited viral glycoprotein synthesis. The effects of these compounds on infectivity indicated that glycosylation is required for the production of infectious virus, though complete processing of the glycoproteins is not essential. In addition, egress of the virions from infected cells probably requires a functional Golgi complex. In the presence of tunicamycin or monensin various degrees of glycosylation of the major glycoproteins occurred, consequently their rates of migration differed from that of the normal glycoproteins. Tunicamycin completely blocked glycosylation of GVP 6/11a/16 and GVP 7. In contrast, GVP 3/9 and GVP 11b were partially glycosylated in the presence of tunicamycin. These results indicated that GVP 6/11a/16 and GVP 7 are N-linked glycoproteins, but GVP 3/9 and GVP 11b contain both N- and O-linked oligosaccharide side chains. Tunicamycin blocked the transport of all viral glycoproteins to the cell surface, suggesting that glycosylation is required for this process. In the presence of monensin, the viral glycoproteins were transported and expressed on the cell surface indicating that transport does not require complete processing of the glycoproteins and may occur via a Golgi-independent pathway. In addition, monensin-treated BHV-1 infected cells could act as target cells in an antibody-dependent cell cytotoxicity assay. Thus, complete glycosylation may not be essential for maintenance of antigenicity and participation in immune destruction.     

Cytolytic T-cell mediated lysis of reovirus-infected cells: requirements for infectious virus, viral particles, and viral proteins in infected target cells

We have studied the phenotype of a heat-sensitive mutation that defines lambda tail gene T. Induction and growth at the nonpermissive temperature of a lambda Tts40 prophage results in production of morphologically normal but biologically inactive tails, which can be activated in vitro by lysates supplying the products of genes T, U, and Z. Thus, gene T acts between genes V and U in the tail assembly pathway or immediately after the completion of tail shaft polymerization. lambda Tts40 lysates also contain a substantial number of morphologically normal phage particles which are deficient in cleavage of the minor tail protein gpH. This result is consistent with the fact that gpH cleavage normally occurs later in the assembly pathway than the time found for gene T action. Purified lambda Tts40 virions that were produced at the permissive temperature are normal with respect to gpH cleavage. However, they are more sensitive to heat inactivation than are wild-type virions, suggesting that the T gene product is in the virion. At the permissive temperature, the mutant protein made by lambda Tts40 is active in vivo even if it has been synthesized at the nonpermissive temperature.     

Morphology and ultrastructure of Lymphocystis disease virus, a fish iridovirus, grown in tissue culture

The morphology and the ultrastructure of the Lymphocystis disease virus (LDV) strain Leetown , a fish iridovirus , was studied by electron microscopy. The virus was grown on bluegill fry (BF-2) cells at 21 degrees. LDV showed an icosahedral shape by ultrathin sections and negative staining, with a diameter of about 200 nm. The shell of the virion seemed to be composed of two unitary membranes with a total diameter of 16 nm. The outer membrane demonstrated swelling in negative staining, exhibiting a central core and the presence of globular subunits at its external surface organized in geometrical arrays of 60 and 90 degrees. Glutaraldehyde fixation preserved very effectively the icosahedral structure with the subunits remaining invisible. The internal structure of the virions was composed of osmiophilic threads or granules of 6 to 8 nm in diameter surrounded by an amorphous material of 10 to 20 nm in thickness. External filaments were observed at the surface of the particles in ultrathin sections, giving the appearance of a halo surrounding the shell. In negative staining these filaments were rarely observed; in one virus preparation, they appeared in bundles.     

Genetic analysis of adenovirus type 2 IV. Coordinate regulation of polypeptides 80K,Illa, and V

An adenovirus type 2 temperature-sensitive mutant, ts3, deficient in virion assembly was studied by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis and electron microscopy. A total of 28 virus-induced polypeptides could be detected, four of which were precursor proteins. At the nonpermissive temperature, ts3 failed to synthesize a newly identified nonstructural polypeptide 80K. Polypeptide V was absent, but it may have been replaced by an arginine-rich polypeptide which was oversynthesized and migrated as a 50K band regardless of temperature. Similarly, polypeptide 55K (= IVa₂) was also oversynthesized and migrated slower than WT-55K (= IVa₂). In addition, several polypeptides were synthesized at increased or decreased levels, compared with WT. Polypeptide IIIa was sometimes resolved into three bands (66K, 67K, 68K) in WT, while ts3-IIIa lacked the 66K and 68K components. Polypeptide 36K was found to be rich in arginine. Consistent with the notion that the processing of PVII into VII requires virion assembly, no processing of ts3-PVII could be observed. By contrast, the cleavage products, VI and VIII, appeared normally, thus disputing the virion assembly requirement previously postulated for these polypeptides. Electron microscopy of ts3-infected cells revealed two hitherto undescribed intranuclear structures, possible tubular forms in addition to normal virions at the permissive temperature, and roughly spherical, core-like structures of 80–100 nm at the restrictive temperature. These results suggest that the pleiotropic effects of the ts3 mutation arrest virus assembly at a corelike structure.     

Virus-specific precursor polypeptides in cells infected with Rauscher leukemia virus: Synthesis,identification, and processing

The synthesis of virus-specific polypeptides in JLS-V9 and JLS-V5 cells infected with Rauscher leukemia virus (R-MuLV) was studied in pulse-chase experiments, followed by radioimmunoprecipitation analysis with polyvalent and monospecific antisera against R-MuLV proteins. Two glycosylated polypeptides with molecular weights of about 8 (env-pr82) were identified as precursors of the virion envelope polypeptides gp69/71 and p15(E). On the other hand, virion polypeptides p30 and pl5 are derived from a 75,000-(gag-pr75) and a 65,000-dalton (gag-pr65) precursor polypeptide. These precursor-product relations were confirmed by analysis of chymotryptic digests of virion polypeptides and their precursors. In the presence of the arginine analog canavanine two polypeptides with molecular weights of 82,000 and 72,000 (gag-pr82 and gag-pr72, respectively) were synthesized instead of gag-pr75 and gag-pr65. Processing of precursor polypeptides is reduced in the presence of canavanine. From these results, we conclude that gag-pr82 is possibly the primary gag-gene product and is cleaved into gag-pr75. These studies provided the following additional information: First, we established that immediately after cleavage of their precursors, gp69/71 is found on the outer surface of the cell and p30, p15, and p12 leave the cell as components of budding virions. Therefore, these polypeptides were detected intracellularly in very small amounts only. Polypeptide p15(E) was present within the cell as well as on its outer surface. Second, despite a great similarity in virus-specific (precursor) polypeptides detected in JLS-V9 and JLS-V5 cells, small differences in molecular weights of some of these polypeptides were observed after SDS-PAGE.     

Effects of viral protein,viral RNA,and some other polyelectrolytes on infection of tobacco protoplasts by TMV

Tobacco cv. Samsun protoplasts were inoculated with TMV in the presence of different polyelectrolytes. Retention of [¹⁴C]TMV was determined by radioactivity of the protoplasts or by infectivity in homogenates of samples frozen immediately after inoculation and washing. Virus yield was determined by infectivity in protoplasts following incubation for 48 hr in light at 28°.Infectious TMV, noninfectious TMV, and TMV protein (100 μg/ml) enhanced virus retention. However, the virus yield for the first substance was essentially lower. When the substances were added to the incubation medium, they decreased virus yield. Bovine serum albumin and casein hydrolysate did not appreciably affect retention; yet, they also decreased virus yield.Virus RNA, whether infective or not, strongly suppressed the virus yield when present in the inoculation medium at a concentration of 1 μg/ml or more. This effect was independent of the presence of actinomycin D in the medium. Experiments with labeled TMV revealed the low virus yield to be the result of a reduction of virus retention in inoculum containing a mixture of TMV and TMV RNA. Similar effects on virus retention and yield were produced by total RNA of animal origin and by dextran sulfate. The authors assume that the three above-mentioned polyelectrolytes block virus adsorption on the plasmalemma by binding with a virus-polyornithine complex.     

Biological, immunological, and biochemical evidence that HIX virus is a recombinant between moloney leukemia virus and a murine xenotropic C type virus

Various parameters of HIX virus were examined to determine its origin and its relationship to other murine C type oncornaviruses. Envelope properties of HIX virus grown in cells of several species were subjected to analyses of host range, interference, and neutralization. Cloned amphotropic HIX virus was adapted to grow in human RD cells. After 6 months in culture, the resulting virus (HIX-RD) could enter mouse cells but essentially lost the capacity of propagating in mouse cells. Interference patterns of HIX and HIX-RD were identical to each other and unrelated to murine ecotropic MuLV interference. MSV(HIX) or MSV(HIX-RD) could not penetrate HIX-, HIX-RD-, or MuX-preinfected cells. However, infection with HIX exhibited a unique one-way interference in that MSV(MuX) could penetrate and transform HIX-preinfected cells. Neutralization of HIX and HIX-RD with relatively type-specific anti-gp70 sera showed that they resembled Moloney (M)-MuLV most closely. Significant neutralization was observed also with anti-Rauscher gp70 or BALB-2 MuX gp70 sera. Both HIX derivatives were acutely susceptible to inactivation with normal mouse sera, a characteristic of xenotropic viruses. Competition radioimmunoassays were performed to determine the antigenic relationship of HIX to other MuLV types. The highly type-specific phosphorylated p12 and the relatively type-specific gag region p15 of HIX were found to be identical to M-MuLV and less related to other murine C-type oncornaviruses. The examination of HIX gp70 with type-specific anti-M-MuLV or anti-C57L MuX gp70 sera showed that it was clearly different from either virus. Tryptic peptide maps of the gag region-p15 and p30 of HIX were identical to corresponding maps of M-MuLV proteins. The gp70 of HIX was unique and different from known eco-, xeno-, and amphotropic murine C type oncornaviruses. Based on known migration patterns of characteristic trypsin- and chymotrypsin-derived peptides of various eco-, and xenotropic MuLV's, it was concluded that gp70 of HIX was related to both MuX and M-MuLV. Tryptic fingerprint maps also revealed several significant differences between parental HIX and its HIX-RD variant. Comparative hybridizations of assorted high-molecular-weight (HMW) virus RNAs with complementary DNA from HIX virus showed that, with unfractionated probes, no significant differences could be seen between HIX and M-MuLV. Based on the above, HIX virus appears to contain predominantly M-MuLV-specific information except for its envelope gene which has been presumably derived from a recombinational event involving corresponding M-MuLV and MuX nucleotide sequences.     

Characterization of a temperature-sensitive, DNA-positive, nontransforming mutant of simian virus 40

We have characterized an early mutant of SV40, tsA1642 (M. J. Tevethia and L. W. Ripper, 1977, Virology, 81, 192–211), which differs from other tsA mutants both in its location on the genome and in its phenotype. Marker rescue experiments position tsA1642 between 0.304 and 0.325 map units in the unique coding region for large T antigen. DNA sequencing within this region reveals a single nucleotide substitution at position 1782. Unlike other tsA mutants, the tsA1642 mutation does not result in the metabolic instability of large T antigen at nonpermissive temperature, nor does it lead to a defect in autoregulation of early gene expression. At nonpermissive temperature in the lytic cycle, tsA1642 accumulates viral DNA, T antigens, and late proteins at near wild-type levels, but produces only low levels of infectious virus. In addition to its defect in lytic growth, tsA1642 is markedly defective in transformation. It is unable to transform Brown Norwegian rat kidney (B/NRK) cells to anchorage-independent growth at 40.5°. However, using the same assay, tsA1642 is nonconditionally defective in the transformation of a continuous line of C57B1/6 mouse embryo fibroblasts. TsA1642 generates transformed B/NRK cell lines some of which are temperature sensitive and some temperature resistant for the maintenance of the transformed phenotype. This mutant, therefore, appears to genetically separate, at least partially, some of the functions of large T antigen required for lytic growth from those required for transformation.     

Structural proteins and lipids in a virus, PBCV-1, which replicates in a Chlorella-like alga

PBCV-1, a large dsDNA-containing virus which replicates in a Chlorella-like green alga, is composed of approximately 64% protein, 25% DNA, and 5-10% lipid on a weight basis. Polyacrylamide gel electrophoresis of the dissociated virus particle resolves 50 to 60 proteins which range in apparent molecular weight from 10,000 to 135,000. Two of these proteins are glycoproteins and at least four are located on the viral surface. The major lipids are phosphatidyl choline, phosphatidyl ethanolamine, and an unidentified component. The effect of organic solvents, surfactants, and chelating and reducing agents on viral infectivity and ultrastructure are reported. Inhibitor studies established that PBCV-1 protein synthesis occurs on cytoplasmic ribosomes.     

Phosphorylation, maturational processing, and relatedness of strain Colburn matrix proteins

The intracellular 66,000 D (66K) and 69,000 D (69K) matrix-like phosphoproteins of strain Colburn cytomegalovirus (CMV) have been compared with each other and with their electrophoretic counterparts in the virion. Three lines of evidence indicate that the 66K and 69K proteins are products of separate genes, and that the intracellular and virion species are closely related. First, "pulse-chase" radiolabeling experiments showed that these proteins have separate precursors; that modification of each to the mature form correlated with phosphorylation; and that phosphorylation of the 69K precursor occurred more slowly than that of the 66K precursor, and resulted in a more dramatic slowing of its electrophoretic mobility. Second, comparisons of the 66K and 69K proteins based on partial proteolysis of [35S]methionine-labeled proteins, using V8 protease, and complete proteolysis of [32P]orthophosphate-labeled proteins, using trypsin or Pronase, provided no evidence of sequence relatedness. These analyses also suggested that the distribution of phosphorylated residues differs in the two proteins--clustered for the 69K and more disperse for the 66K. Phosphoamino acid analyses showed only phosphoserine in the 66K protein. The 69K protein contained, in addition to phosphoserine, an electrophoretically faster moving, unidentified spot. And third, immunological comparisons showed these proteins to exhibit little or no antigenic cross-reactivity. They did, however, demonstrate that the nuclear proteins are immunologically cross-reactive with their respective virion counterparts. Additional comparisons of these nuclear and virion proteins established that the virion 69K protein (v69) differs in electrophoretic mobility and net charge from the nuclear 69K protein but that it, as well as the virion 66K protein, has a two-dimensional phosphopeptide pattern similar to its nuclear counterpart.