Enhancement of peritoneal macrophage activity by bovine gamma globulin in mice

Mice treated with bovine gamma globulins showed an increased resistance to Salmonella typhimurium infection. This phenomenon seems to be bound to an increase of peritoneal macrophage phagocytic activity, as shown by the method of chemiluminescence, in experiments performed on peritoneal macrophages from mice treated with bovine gamma globulin.     

L'absorption du facteur «L.E.» par des noyaux cellulaires isolés

Summary The serum containing the L.E. factor loses its activity after having been put in contact with isolated cell nuclei. The electrophoretic examination shows a clear diminution of the gamma globulin and a slight diminution of the globulin alpha 2. That the factor responsible for the L.E. phenomenon can be absorbed by isolated cell nuclei is an argument in favor of the hypothesis that this factor is a substance having the character of an antinuclear anti-body, without one being able to exclude with certitude the possibility that this factor is an enzyme.     

Immunosuppressive effect of a human serum ferroprotein of hepatic origin, alpha 2 H globulin. Study on blastic transformation of normal lymphocytes in the presence of phytohemagglutinin]

The alpha2 H globulin, a glycoferroprotein, has been found in the serum of patients with malignant diseases. Its level varies according to the evolution of the disease. The activity of this protein has been studied on the normal lymphocytes cultivated in presence of phytohemagglutinin. This study has showed that 5 mug/ml of alpha2 H globulin can inhibit the blastic transformation. The inhibitory effect is proportional to the amount of alpha2 H globulin added as judged by the tritiated thymidin incorporation. The study of morphological aspects of the lymphocytes shows that alpha2 H globulin acts upon the synthesis of the cytoplasmic proteins.     

Phytotoxins as tools in breeding and selection of disease-resistant plants

Conventional plant breeding for resistance to pathogens, although successful, is in many cases still too slow to keep pace with pathogen adaptation, and suffers from the lack of genetic variability in cultivated varieties. Phytotoxins, because of their role in disease development, have been proposed as convenient markers for early screening of resistant genotypes and as selective agents for in vitro selection. The present review summarizes, firstly, the evidence for a genetic correlation between tolerance to toxins and resistance to pathogens, with particular reference to host-selective toxins (HST) and factors affecting early screening. There follows a discussion of results obtained from the use of phytotoxins for in vitro selection of resistant plants. The conclusion is drawn that this practice, while potentially useful in the case of HST, leads to contradictory results when ill-defined toxins or culture filtrates are used. Finally, prospects for future research are adumbrated.     

Effects of gamma irradiation on dermal equivalents in vitro

Summary Dermal equivalents (DE), collagen lattices, were produced in vitro and used as a model for studying the possible role of a pure population of fibroblasts in post-radiotherapeutic dermal fibrosis. Single doses of gamma irradiation induced a partial inhibition of the collagen lattice retraction and of protein synthesis. The collagen production was less inhibited than was synthesis of non-collagen protein, which resulted in an increase of the relative amount of collagen synthesized by irradiated fibroblasts. These data suggest that gamma irradiation might be able to select some fibroblast clones able to produce increasing amounts of collagen. This selection process could be involved in the development of tissue fibrosis after therapeutic radiation.     

Effects of gamma irradiation on dermal equivalents in vitro

Dermal equivalents (DE), collagen lattices, were produced in vitro and used as a model for studying the possible role of a pure population of fibroblasts in post-radiotherapeutic dermal fibrosis. Single doses of gamma irradiation induced a partial inhibition of the collagen lattice retraction and of protein synthesis. The collagen production was less inhibited than was synthesis of non-collagen protein, which resulted in an increase of the relative amount of collagen synthesized by irradiated fibroblasts. These data suggest that gamma irradiation might be able to select some fibroblast clones able to produce increasing amounts of collagen. This selection process could be involved in the development of tissue fibrosis after therapeutic radiation.     

Organoselenides as potential immunostimulants and inducers of interferon gamma and other cytokines in human peripheral blood leukocytes

Summary A number of organoselenium compounds have been described as anti-inflammatory, antioxidant, glutathione peroxidase-like agents and inhibitors of prostaglandin synthesis. Here we report that bis [2-(N-phenyl-carboxamido)]phenyl diselenide, 2-phenyl-1,2-benzisoselenazol-3(2H)-one (Ebselen) and related compounds are inducers of interferon gamma (IFN-) and tumor necrosis factor (TNF) in human peripheral blood leukocytes. The IFN and TNF response was rapid, occurring within 20 h, and high-up to 1000 and 2000 units ml^–1-and was clearly related to the dosage and the structure of the compounds. The action of the compounds and phytohemagglutinin was synergistic. The IFN gamma and TNF production was reduced after removing adherent cells. Although the mode of action of the compounds is not known, they appear to interact directly or indirectly with both adherent and non-adherent leukocytes, and stimulate the synthesis of a set of different cytokines including factors controlling the cell proliferation. Therefore, organoselenides may be regarded as the biological response modifiers.     

A new type of mutant ofEuglena which produces permanently bleached progeny by darkness

Summary A new type of mutant ofEuglena gracilis strain Z was isolated. In the light-grown culture, it contains 5–20% of bleached cells which have irreversibly lost the ability of chloroplast formation. When once grown in the dark, differing from the case with the wild type, it segregates only bleached cells, probably due to the inability of the replication of proplastids in darkness. Cell multiplication under the inhibition of chlorophyll synthesis or photosynthesis in the light also produces bleached cells.     

Demonstration of testosterone secretion by testicular tissue of hypophysectomized boar as affected by HCG in organ culture]

Boar Leydig cells undergo a strong atrophy from 1 to 3 months after hypophysectomy but can be reactivated by the gonadotropin HCG in organ culture conditions. This reactivation which appeared at histological and ultrastructural level was evidenced by the capacity of testicular tissue to synthesize testosterone as judged by radioimmunoassay. Both synthesis in the tissue and release into the medium increased according the incubation time with HCG; the adjonction of 17 alpha-OH-pregneolone to culture medium led to increase the intra and extra-tissular concentration of testosterone.     

Specific cleavage of insulin-like growth factor-binding protein-1 by a novel protease activity

Insulin-like growth factor-binding protein-1 (IGFBP-1) is secreted in a highly phosphorylated form that binds IGF-I with high affinity and is resistant to proteolysis. We have purified IGFBP-1-specific protease activity from the urine of an individual with multiple myeloma. This protease efficiently cleaves both phosphorylated and non-phosphorylated IGFBP-1 at Ile130-Ser131, generating fragments that together have higher association and dissociation rates for IGFs compared with intact IGFBP-1. The proteolytic fraction contained azurocidin, a protease homologue hitherto considered inactive. After cleavage of IGFBP-1, there was a lower affinity, but higher capacity for IGF-I binding, suggesting both N- and C-terminal fragments may interact with ligand independently. There was decreased inhibition of IGF-II-stimulated cell growth and glucose uptake. Alone, proteolysed IGFBP-1 stimulated glucose uptake in muscle. We conclude that specific cleavage of IGFBP-1 at target tissues is important in cellular growth and metabolism and opens novel strategies for targeting IGFBP-1 in treatment of disease.     

Stimulation of proliferation of rat spleen cells, in vitro, by a nonspecific acute inflammatory exudate. Modulation of cell response to phytohemagglutinin (PHA)]

The effect of an acute non-specific inflammatory exudate with mitogenic activity on macrophages in culture has been tested on the spontaneous and PHA-induced DNA synthesis of spleen cells in vitro. Stimulatory effect of this exudate was observed on spontaneous DNA synthesis which was detectable over a range of 1 : 4 to 1 : 4,000 concentrations. After optimal PHA stimulation, an inhibition of mitogen-induced DNA synthesis was observed when the cells were exposed to the highest concentrations (up to 1 : 128) of the exudate. Thereafter, the phenomenon could be reversed and the stimulation was maximal at a concentration of 1 : 2,000. When a sub-optimal dose of PHA was used, the simulatory effect was more pronounced and detected from 1 : 8 up to 1 : 4,000 concentrations.     

Resistant penicillin-binding proteins

Low-affinity penicillin-binding proteins (PBPs), which participate in the β-lactam resistance of several pathogenic bacteria, have different origins. Natural transformation and recombination events with DNA acquired from neighbouring intrinsically resistant organisms are responsible for the appearance of mosaic genes encoding two or three low-affinity PBPs in highly resistant strains of transformable microorganisms such as Neisseria and Streptococcus pneumoniae. Methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococcal strains possess the mecA determinant gene, which probably evolved within the Staphylococcus genus from a closely related and physiologically functional gene that was modified by point mutations. The expression of mecA is either inducible or constitutive. A stable high-level resistant phenotype requires the synthesis of a normally constituted peptidoglycan. Enterococci have a natural low susceptibility to β-lactams related to the presence of an intrinsic low-affinity PBP. Highly resistant enterococcal strains overexpress this PBP and/or reduce its affinity.     

Reversion of virus N-1 resistant mutant of blue-green algaNostoc muscorum

Summary The reversion of N-1 virus resistant strain of the algaNostoc muscorum was studied by inoculating parent virus in the resistant culture at various incubations. A fraction of virus resistant cells reverted to wild sensitive type with the reversion rate of 3.99×10^–6/cell/generation.We gratefully acknowledge Dr H.K. Pande and Dr S. Patnaik, Crops and Soils Division.     

Expression of the mutant gene for L-gulono-γ-lactone oxidase in scurvy-prone rats

A mutant strain of Wistar rats with L-gulono--lactone oxidase deficiency has recently been established. To investigate this deficiency by DNA and RNA blot hybridization analyses, a fragment of a previously cloned cDNA encoding rat L-gulono--lactone oxidase was used as a probe. When genomic DNA of the mutant rat was digested with several restriction enzymes, the probe hybridized to fragments of the same sizes as those produced from DNA of normal rats. Poly(A)⁺RNA from the liver of the mutant rat was found to contain an L-gulono--lactone oxidase-specific mRNA of a normal size at a comparable level to that of normal rats. An in vitro translation experiment revealed that the mRNA programmed the synthesis of an enzyme protein which had the same molecular weight as that of the translational product of the normal mRNA, although the amount synthesized was markedly reduced as compared with that synthesized with the normal mRNA. In accordance with this observation, a very low but definite degree of L-gulono--lactone oxidase activity was detected in the microsomes of the mutant rat by a newly developed, highly sensitive method.Acknowledgments. The authors thank Dr Susumu Makino, Shionogi Research Laboratories, Shionogi & Co., Ltd, Japan, for his kind donation of normal (ODS- +/+) and ODS (ODS-od/od) rats. This work was supported in part by Grant-in-Aid (59570103) for Scientific Research from the Ministry of Education, Science and Culture of Japan.     

Regulation of ppApp synthesis during sporulation of a conditionally asporogenous rifampin mutant ofBacillus subtilis

Summary The intracellular synthesis of ppApp in a conditionally asporogenous rifampin-resistant mutant ofBacillus subtilis stimulated to sporulate in the Sterlini-Mandelstam (SM) medium supplemented with ppApp is negligible and comparable to that of the non-sporulating culture. The formic acid extract from the sporulating culture stimulates sporulation of the mutant in SM medium.This paper was presented at the Annual Meeting of the American Society for Microbiology in Dallas, Texas, in March 1981. This work was supported in part by a grant from Research Corporation, New York, N.Y., USA.     

Effect of hormones and cyclic AMP on γ-glutamyltranspeptidase activity of rat mammary gland explants

Summary -Glutamyl transpeptidase activity was assayed in midpregnant rat mammary gland explants at 14, 22 and 38 h, in the presence and absence of insulin, prolactin and corticosterone. With these 3 hormones the explants attained the characteristics of a secretory gland after 22 h of tissue culture, at which time the enzyme exhibited its maximal activity. The addition of dibutyryl cyclic AMP in the presence of the 3 hormones produced a significant increase in enzyme activity, which was maximal with a 1 mM concentration of the cyclic nucleotide. A similar effect was observed when theophylline or theophylline plus dibutyryl cyclic AMP were added to the culture medium.This work was supported by grant B1138-8333 from the Departamento de Desarrollo de la Investigación, Universidad de Chile.     

Interferon-beta can induce the production of plasminogen activator by cultured human cancer cells

Three cultured human cell lines, renal cancer cells (ACHN), bladder cancer cells (EJ), and fibroblasts transformed in culture by Co-60 gamma rays (KMST-6), when treated with interferon-beta, produced 1.5 to 4 times as much plasminogen activator as the untreated control cultures. This enhanced production of PA was inhibited by cycloheximide or actinomycin D.     

Cellular control of the tick-borne virus antigen production in persistently infected cell culture.

The influence of inhibition or stimulation of cellular DNA synthesis on tick-borne virus antigen production in persistently infected cell culture was studied. Either mitomycin C or cytosine-arabinoside caused cessation of antigen-containing cell number increase. Stimulation of cellular DNA synthesis by growth medium change increased the level of antigen-containing cells. When HEp-2-Sof culture was synchronized, a correlation was observed between the entrance of cells into DNA synthesis phase and the increase of proportion of antigen-containing cells.     

Bovine microvascular endothelial cells of separate morphology differ in growth and response to the action of interferon-γ

Five cell types recently isolated from the bovine corpus luteum differed in their epithelioid morphology and their cytoskeleton, but shared common criteria of microvascular endothelial cells^1,2. To give strong evidence for the separate entity, the growth rate of the 5 phenotypically different cells was studied. They were seeded at low density on day 0. Most of these cells were treated with 200 to 1000 U recombinant bovine interferon- (IFN-) for 3 days. The untreated remainder served as controls. Cell counts were made for all cultures on days 4, 7, 10 and 13. morphology: 13 d after treatment with IFN- senescent cells as well as intact cells occurred in cultures of cell types 1 to 4. Cultures of cell type 5 were apparently unchanged and resembled their untreated counterparts. Desminpositive cells in cultures of cell type 2 developed cell processes. Growth rate: In the absence of IFN-, the growth rate was high for cell types 3 and 4, moderate for cell type 1, and low for cell types 2 and 5. The presence of IFN- caused anti-proliferative effects. These were higher for cell types 3 and 4 than for cell types 1 and 2. IFN- could be cytotoxic on cell type 3. In contrast, the cytokine tended to support the cell growth of cell type 5. These findings substantiate the postulate that endothelial cells exhibiting separate morphology in culture also function differently.     

Cellular control of the tick-borne virus antigen production in persistently infected cell culture

Summary The influence of inhibition or stimulation of cellular DNA synthesis on tick-borne virus antigen production in persistently infected cell culture was studied. Either mitomycin C or cytosine-arabinoside caused cessation of antigen-containing cell number increase. Stimulation of cellular DNA synthesis by growth medium change increased the level of antigen-containing cells. When HEp-2-Sof culture was synchronized, a correlation was observed between the entrance of cells into DNA synthesis phase and the increase of proportion of antigen-containing cells.