Establishment of a C3Hf Mammary Tumor Cell Line Expressing Endogenous Mouse Mammary Tumor Virus: Antigenic and Genetic Relationships of This Virus with Highly Oncogenic Mouse Mammary Tumor Viruses

A single-cell clone of C3Hf mammary tumor cells (clone 14) was developed into a continuous cell line expressing high levels of endogenous mouse mammary tumor virus (MMTV) with less than 0.1% murine leukemia virus expression. Comparison of the C3Hf MMTV protein profile on sodium dodecyl sulfatepolyacrylamide gel electrophoresis with that of C3H MMTV revealed that the protein content of the two viruses was quite similar. However, oligonucleotide fingerprints obtained of MMTV 70S RNA revealed that approximately 20% of the large oligonucleotides examined were unique to each virus. The oligonucleotide fingerprint indicated that although the viruses were similar, they differed in their genetic content. The differences in the two viruses extended to immunological differences in the major envelope glycoprotein, gp52. C3Hf MMTV competed only partially in a homologous radioimmunoassay for gp52 of C3H MMTV, whereas C3H MMTV gave complete competition, indicating that gp52 of C3H MMTV contained type-specific determinants not present on gp52 of C3Hf MMTV. Comparison of C3Hf MMTV with highly oncogenic C3H, GR, and RIII MMTVs in a homologous C3H MMTV gp52 assay gave two patterns of reactivity: complete competition by GR and C3H MMTV and incomplete competition by C3Hf and RIII MMTV. Absorption of anti-C3H MMTV serum by either C3Hf MMTV or RIII MMTV removed all antibodies against both viruses but not against GR and C3H MMTVs. These results indicate that C3H and GR MMTVs are more closely related to each other than to RIII and C3Hf MMTVs.     

Mice with Spontaneous Mammary Tumors Develop Type-Specific Neutralizing and Cytotoxic Antibodies Against the Mouse Mammary Tumor Virus Envelope Protein gp52

Sera from C3H mammary tumor-bearing mice contain cytotoxic antibodies for mouse mammary tumor virus (MMTV)-producing cells, based on (51)Cr release in a complement-dependent serum cytotoxicity assay. The cytotoxic antibodies could be absorbed by purified C3H MMTV gp52 and C3H MMTV-infected cat cells (C3H [MMTV] CrFK) containing cell surface MMTV gp52. However, purified MMTV p27 and uninfected CrFK cat cells were negative. Absorption of the sera with GR (MMTV) CrFK cells also removed all of the cytotoxicity, whereas absorption with RIII (MMTV) CrFK cells was negative, even though all three infected cat cells contained equivalent amounts of gp52. The same C3H cytotoxic sera also neutralized the focus-forming capacity of a C3H MMTV pseudotype of Kirsten sarcoma virus containing MMTV gp52. In contrast, sera from mammary tumor-bearing GR and RIII mice did not neutralize the pseudotype. Furthermore, neutralization could be achieved only by anti-gp52 but not by anti-gp36, -p27, -p14, or -p10 C3H MMTV sera. The gp52's of C3H, GR, and RIII MMTV could also be distinguished by using a type-specific competition radioimmunoassay employing (125)I-gp52 of C3H MMTV and a hyperimmune rabbit anti-C3H MMTV serum. To demonstrate these differences directly, we studied the primary structure of gp52 on the surface of the C3H, GR, and RIII (MMTV) CrFK cells. Two-dimensional tryptic peptide maps of the cell surface lactoper-oxidase-catalyzed iodinated gp52's revealed a greater number of peptides common to the gp52's of C3H and GR MMTVs than to RIII MMTV gp52. These results demonstrate that gp52 is a major target antigen for both cytotoxic and neutralizing antibodies, that the cell surface and virion-associated gp52's of C3H, GR, and RIII MMTV contain both group- and type-specific determinants, and that C3H and GR MMTV gp52's are antigenically more related to each other than to RIII MMTV gp52. Furthermore, C3H mammary tumor-bearing mice develop type-specific antibodies capable of recognizing unique gp52 determinants and, therefore, are able to distinguish the gp52 of C3H MMTV from the gp52's of GR and RIII MMTV.     

On-line measurements of culture fluorescence: Method and application

Summary In this paper a new probe allowing the measurement of NAD(P)H-dependent culture fluorescence in a bioreactor is presented. This sterilizable probe can be inserted in every bioreactor using a standard fitting of 25 mm. Under well defined conditions high specificity and sensitivity as well as high stability are further advantages of this probe. Application examples are given to demonstrate the operation possibilities of this fluorescence probe. In batch growth the culture fluorescence can be used for on-line estimation of biomass concentration. Metabolic alterations due to substrate of oxygen deficiency can easily be detected by fluorometric measurements. In kinetic studies the fluorescence probe is of great use because of a very small time delay.     

Chemotaxonomic significance of the xanthomonadins,novel brominated aryl-polyene pigments produced by bacteria of the genus Xanthomonas

The cell pigments produced by strains of Xanthomonas spp. (including representatives of all five presently recognized taxospecies of these phytopathogenic bacteria) have been isolated as isobutyl esters, purified, and characterized in terms of electronic absorption, chromatographic and co-chromatographic, and mass spectrometric properties. This comparative examination reveals that these bacteria produce brominated aryl-polyene pigments which are given the trivial name xanthomonadins. The several xanthomonadins usually occur as mixtures which have been resolved by chromatography and sorted into several Pigment Groups, thus enabling a more rational approach in our on-going systematic study of their exact chemical structures and biosynthesis. From what is presently known, some of the xanthomonadins might differ from xanthomonadin I, the exact structure of which has previously been determined in material from Xanthomonas juglandis ICPB XJ103, by their being monobrominated (rather than dibrominated, as is xanthomonadin I), by their having the equivalent of one methyl group less than does xanthomonadin I, and/or in other ways. The pigments of Xanthomonas ampelina (a little known and possibly questionable member of this genus) seem somewhat different from the pigments of the other Xanthomonas spp. The ability to form these distinctive xanthomonadin pigments is a useful chemotaxonomic marker for the genus Xanthomonas, since such pigments are not known to be formed by taxonomically or ecologically adjacent bacteria. Sufficient characterization of this assemblage of xanthomonadin pigments is presented so that they can be isolated and identified routinely on the basis of the aforementioned properties.     

Leaf pretreatment with senescence retardants as a basis for oat protoplast improvement

Protoplasts obtained from oat leaves floated on buffer for 18hr show high nuclease activity, low rates of incorporation ofamino acids and nucleosides into macromolecules, and high ratesof spontaneous lysis. Addition to the leaf flotation mediumof the senescence retardants cycloheximide or kinetin, of thedibasic amino acids L-lysine or L-arginine, or of the diaminesputrescine or cadaverine reduces the rise in nuclease activityand spontaneous lysis of protoplasts, and increases the rateor extent of presumptive protein and nucleic acid synthesis.The diamines, which also retard chlorophyll degradation in theexcised leaves, appear to act both on the membrane and on systemscontrolling macromolecular synthesis and breakdown. By contrast,the senescence promoter L-serine hastens chlorophyll degradationfrom excised leaves and does not improve protoplasts derivedfrom those leaves. (Received July 4, 1977; )     

Surgical Management of Epilepsy

Therapy with anticonvulsant drugs reduces the frequency and severity of seizures in many but not all epileptic patients. Unfortunately, in a significant number control remains poor even when maximal doses of multiple anticonvulsant drugs are given. Some of these patients are candidates for surgical treatment of epilepsy. The operative management of convulsive disorders is a well-established technique and is available in some centers. In selected cases, such operations are both safe and effective, with good longterm improvement or complete control in 76 percent of patients. We have summarized the 24-year experience with surgical operation for epilepsy at the University of Washington Medical Center.     

Familial Mediterranean Fever: Recent Advances in Pathogenesis and Management

The success of colchicine therapy in the management of familial Mediterranean fever has provided new direction to investigations into the pathogenesis of this disease. Examination of HLA antigen frequencies in 53 patients with familial Mediterranean fever and appropriate controls, as well as various immunologic studies have yielded no significant differences. However, B lymphocyte typing and assays for immune complexes, lymphokines and prostaglandins may be of potential interest. Preliminary studies indicate that leukocytes of patients with familial Mediterranean fever release increased amounts of lysozyme (P<0.01), when subjected to high temperatures, and of both lysozyme and myeloperoxidase at low osmotic concentrations. The known and potential effects of colchicine on leukocyte and cellular metabolism, and the current status of colchicine prophylaxis are reviewed. In patients receiving an optimum colchicine dose of 1.5 to 1.8 mg per day, side effects have been minimal and the frequency of attacks has been decreased significantly.     

Plants interact with microbial polysaccharides

Plants are resistant to almost all of the microorganisms with which they come in contact. In response to invasion by a fungus, bacterium, or a virus, many plants produce low molecular weight compounds, phytoalexins, which inhibit the growth of microorganisms. Phytoalexins are produced whether or not the invading microorganism is a pathogen. The production of phytoalexins appears to be a widespread mechanism by which plants attempt to defend themselves against pests. Molecules of microbial origin which trigger phytoalexin accumulation in plants are called elicitors. Structural polysaccharides from the mycelial walls of several fungi elicit phytoalexin accumlation in plants. Approximately 10 ng of the polysaccharide elicits the accumulation in plants of more than sufficient amounts of phytoalexin to stop the growth of microorganisms in vitro. The best characterized elicitors have been demonstrated to be β-1,3-glucans with branches to the 6 position of some of the glucosyl residues. Oligosaccharides, produced by partial acid hydrolysis of the mycelial wall glucans, are exceptionally active elicitors. The smallest oligosaccharide which is still an effective elicitor is composed of about 8 sugar residues. Bacteria also elicit phytoalexin accumulation in plants, but the Rhizobium symbionts of legumes presumably have a mechanism which allows them to avoid either eliciting phytoalexin accumulation or the effects of the phytoalexins if they are accumulated. The lectins of legumes bind to the lipopolysaccharides of their symbiont, but not of their non-symbiont, Rhizobium. It is not known whether the lectin-lipopolysaccharide interaction is involved with the establishment of symbiosis. However, evidence will be presented that suggests that lectins are, in fact, enzymes capable of modifying the structurs of the lipopolysaccharides of their symbiont, but not of their non-symbiont, Rhizobium. It will also be shown that the lipopolysaccharides isolated from different Rhizobium species and from different strains of individual Rhizobium species have different sugar compositions. Thus, the different strains of a single Rhizobium species are as different from one another as the different species of Salmonella and other gram-negative bacteria. This conclusion is substantiated by experiments demonstrating that antibodies to the lipopolysaccharide from a single Rhizobium strain can differentiate that strain from other strains of the same species as well as from other Rhizobium species. The role in symbiosis of the strain-specific O-antigens is unknown.     

The paracellular pathway in toad urinary bladder: Permselectivity and kinetics of opening

Summary Determination of serosa-to-mucosa fluxes of Na, K, and Cl yields information about the properties of the shunt pathway in toad urinary bladder. We show that measurement of these fluxes at 30-sec intervals following an abrupt increase in mucosal osmolality yields evidence on the rate of opening of the path and of its permselectivity. The relationship between the fluxes of any pair of these ions indicates that the shunt is paracellular both before and after the increase in conductance effected by hyperosmolality and that the transepithelial PD affects the permselectivity properties (at 0 mV,P _K/P _Na/P _Cl= 10.710.57; at +25 mV,P _K/P _Na/P _Cl=10.710.99). The relationship between any of the fluxes and the total transepithelial conductance is linear and yields an estimate of cellular conductance (the intercept of this regression on the conductance axis) which is in accord with that measured electrically. These studies provide information on tight junction permeability to nonelectrolytes, as well. Finally, they provide new information about the role of the shunt path as a controlling influence on transepithelial sodium transport and raise the possibility that, in both leaky and tight epithelia, differences in transepithelial conductance from tissue to tissue, organ to organ, and species to species may be due, in the absence of edge damage, to changes in conductance of the paracellular pathway.