A protein of Halobacterium halobium immunologically related to the v-myc gene product

A 70 kDa protein of Halobacterium halobium cross-reacts with an antiserum directed against the v-myc gene product of the avian myelocytomatosis virus (MC29). This cross-reaction is in agreement with hybridization studies which indicate that H. halobium possesses DNA and RNA sequences homologous to the v-myc gene.     

Potential antiradiation drugs containing no nitrogen, and related compounds

Capabilities are reported of di- and higher sulfides (RSnR') terminated by sulfinate functions [-S(O)O-] for protecting mice against otherwise lethal effects of ionizing radiation. With the use of congeners, structure-activity correlations are developed for the effects of esterification of the sulfinate function, of changing the length of the chain of sulfur atoms, of reduction to a mercapto sulfinate, and of changing the substituents R and R' to chiral and other types of groups. Neither a trisulfide nor a sulfinate by itself was significantly radioprotective. The key requirement for radio-protection in the series appears to be the presence of a sulfur function (-Sn-) from which a thiol can be engendered by a neighboring-group effect of an electron-donating group; sulfoxide functions may afford alternatives to sulfinate functions as such neighboring groups. The relevance of structure-activity relations to the chemical and biological mechanisms involved in the radioprotective activities is discussed.     

Specificity analysis of human anti-DNA antibodies

Human hybrids producing anti-DNA antibodies were generated by the fusion of pokeweed mitogen-stimulated splenic lymphocytes from a child with sickle cell anemia to GM4672. Of 19 hybrids, three (15%) produced anti-DNA antibody as detected by an enzyme linked immunosorbent assay. One subclone from each of these three hybrids was then characterized. All produced IgM antibody in large amounts ranging from 22 to 266 micrograms/ml per million cells per 24 hr. All three antibodies bound both double- and single-stranded DNA. Competitive inhibition assays revealed the greatest inhibition of DNA binding with the ribohomopolymers polyinosinic and polyguanylic acid. A complex pattern of cross-reactivity with various other polynucleotides and with some phospholipids was observed. Subtle differences were found among the three antibodies in light chain class and some of the binding specificities. By using a modified Farr assay, all three monoclonals were found to be of low to intermediate affinity. These results confirm that anti-DNA antibodies apparently equivalent to those seen in patients with SLE can be derived from "normal" nonautoimmune individuals.     

Relationships of the Col plasmids E2, E3, E4, E5, E6, and E7: Restriction mapping and colicin gene fusions

Thirteen ColE plasmids representing the E2-E7 types have been compared by restriction mapping. Over 80% of their restriction sites were found to be similarly positioned, indicating that these plasmids share a common structure. Three variants are ColE2-CA42 and ColE7-K317, both of which contain 1.8-kb DNA segments in place of a 2.5-kb segment common to the other plasmids, and ColE6-CT14, which has an additional 5.0-kb DNA segment compared to the other plasmids. The colicin (col), immunity (imm), and colicin release (hic) genes of these plasmids have been localized to regions corresponding to those known for ColE3-CA38 and ColE2-P9, with the imm and hic genes adjacent to the 3' end of the col gene. Active colicin is produced from hybrid col genes containing 5' and 3' ends from different E-type plasmids. The 3'-termini of the fused col genes specify the colicin type.     

Bufonid nucleocytoplasmic hybrids arrested at the early gastrula stage lack a fibronectin-containing fibrillar extracellular matrix

Summary Most hybrids betweenBufo bufo andB. calamita obtained by nuclear transplantation become arrested at the early gastrula stage. In both parental controls and the hybrid embryos, the presence and distribution of extracellular matrix was analysed with fluorescent wheat germ agglutinin and by immunolabelling with antibodies directed against fibronectin. InB. bufo andB. calamita gastrulae and in the few hybrids that complete gastrulation, the inner surface of the blastocoel roof is covered by a fibronectin-rich fibrillar matrix. In nucleocytoplasmic hybrids whose development was arrested at the gastrula stage, the fibronectin-containing extracellular matrix was either totally absent or poorly developed and disorganized.     

Time course localization of immunoglobulin M monoclonal antibody and its fragments in leukemic tumor-bearing mice

Summary In vivo localization of a mouse monoclonal antibody (F₂-10.23 IgM) binding leukemic L 1210 cells was studied in DBA/2 mice bearing an L 1210 tumor. F(ab)₂ fragments were prepared and their specific binding to L 1210 cells was analyzed by flow cytofluorometry. Radiolocalization studies were performed by using ¹²⁵I- or ¹³¹I-labeled IgM monoclonal antibody or its F(ab')₂ fragments to ascertain their capacity to visualize the L 1210 tumor. F(ab)₂ fragments were cleared more rapidly than the whole IgM; the clearance was as fast in healthy as in tumor-bearing mice. The tumor-to-muscle ratio observed 24 h after injection of ¹²⁵I-radiolabeled F(ab)₂ fragments and ¹²⁵I-radiolabeled IgM was 10; the radioactivity level in the blood with F(ab)₂ fragments was lower than with IgM, and so -camera imaging was workable with F(ab)₂ fragments without background substraction. The tumor localization was studied over a period of 5 days by recording the distribution of the iodinated fragments in the tumor-bearing leg compared with that in the normal leg, and by computer analysis of the region of interest. F(ab)₂ fragments gave better results than intact IgM in tumor visualization. Nevertheless, the rapid clearance of this antibody or its F(ab)₂ fragments make them hardly suitable as carriers of toxic drugs. Abbreviations used are: MEM Minimum essential medium; SDS sodium dodecylsulfate; PAGE polyacrylamide gel electrophoresis     

Human autologous rosettes. IV. Their relation with interleukin 2 activity production and natural killer cells in cancer patients

Peripheral blood lymphocytes (PBL) of solid-tumor-bearing cancer patients produced a lower interleukin 2 (IL-2) activity after lectin stimulation than did those from normal subjects. Moreover natural killer (NK) cell activity and autologous rosette forming (ARF) cell rate are found significantly correlated with IL-2 production in these patients. No direct relation is observed between ARF cell ratio and NK cell activity in a given patient. A central role for IL-2 in cancer patient immune dysfunctions is suggested. Two lines of pathogenetic mechanisms are documented. First, PBL exhibited cellular function defects, namely, autologous receptor expression, IL-2 production, and NK activity. Second, these dysfunctions involved, at least partly, plasma factors. The possibility of specific deficiency, (e.g., thymic factors) is not documented. Conversely it is demonstrated that patient plasma contain immunosuppressive factor(s) that block(s) IL-2 production and ARF cell expression. Involvement of ARF cell receptor in T-cell activation is discussed.     

Use of microcalorimetry for the characterization of marine metabolic activity at the water-sediment interface

Metabolic processes occurring at the sea-water-sediment interface were studied using a circulation flow microcalorimeter. A methodology was developed to characterize rapid and global changes in metabolism and energy flow, not easily detectable with reductionist approaches. Sea water was pumped continuously, 5–10 mm above the sediment, in experimental microcosms; a 100-μm filter prevented passage of meiofauna. This “circulating interface” was taken through the microcalorimeter and from there to an oxygen electrode, and was returned to the microcosm. The microcosms were experimentally eutrophicated using peptone (4 mg·ml ^?1). The relationship between heat production and oxygen tension in the circulating interface has been compared with ATP production, ¹⁴CO₂ and [¹⁴C]particulate matter turnovers. Initial heat steady-state production rises to a peak of 130 to 180 μW·ml^?1 in 6 to 8 h after peptone treatment. The microcalorimetric peak is closely correlated with ¹⁴CO₂ turnover and partially correlated with micro-events on the pO₂ curve. ATP concentration and particulate-¹⁴C turnover increase constantly and then stabilize, with the establishment of a new heat production steady state. The approach provides an indication of the temporal behaviour of complex mixtures of microorganisms and ciliates at the water-sediment interface, and gives holistic measurements of energy flow after induced perturbation (eutrophication) of the ecosystem. Although many problems remain to be solved in this field, it is shown here that flow microcalorimetric measurements can be used to monitor the effects of addition of reagents like pollutants and nutrients.     

Cloning structural gene sacB, which codes for exoenzyme levansucrase of Bacillus subtilis: expression of the gene in Escherichia coli.

A clone bearing the structural gene sacB, coding for the exoenzyme levansucrase, was isolated from a library of Bacillus subtilis DNA that was cloned in phage lambda charon 4A on the basis of the transforming activity of the chimeric DNA. This lambda clone also was found to contain the sacR and smo loci. Subcloning the sacB-sacR region in plasmid pBR325 resulted in a clone which directed levansucrase synthesis in Escherichia coli. The nucleotide sequence coding for the secreted protein was localized on the physical map of the cloned DNA.