The effect of monochromatic radiation in the range 350 to 750 nm on the carotenogenesis in Verticillium agaricinum

An action spectrum for carotenogenesis in V. agaricinum has maxima at 395, 433, 660 and 737 nm. In a previous study it had been shown that a light-minus-dark difference spectrum of a crude extract from V. agaricinum had maxima at 390 and 420 nm, and furthermore a red, far-red interaction suggesting phytochrome involvement has been proposed. All these data suggest that there may be at least two photoreceptor systems operating in the photoinduction process here; one for the near-ultraviolet (UV-A)-mediated carotenogenesis, presumably a novel pigment, and the other for the red, far-red region, most likely phytochrome.     

Characteristics of synthesized RNA in the isolated and perfused rat liver

The incorporation of 3H-orotic acid into nuclear and microsomal RNA from isolated perfused rat liver has been studied. The specific radioactivity of nuclear RNA indicates that the efficiency for RNA synthesis in the perfused liver is similar to that of the liver 'in vivo'. In contrast, the microsomal RNA specific radioactivity is well below that observed 'in vivo'. This may indicate a slower transport of the labelled RNA from the nucleus to the cytoplasm. Labelling pattern of total nuclear RNA, nuclear poly(A) containing RNA and microsomal RNA appear to be in line with these assumptions.     

Sterols from three Lactarius species

The sterol composition of three fungi was determined. Ergosterol is the major sterol, accompanied by other closely related sterols.     

Infectious primate type C virus proviral DNA in productively infected cells.

Cell lines competent to infection by DNA from cultures chronically infected by type C viruses of the simian sarcoma virus and baboon endogenous virus groups were identified. Significant differences were observed in the relative susceptibility of some cell lines to infection by a given proviral DNA. Practical applications of transfection techniques for the separation of viruses from dually infected cultures and to free virus stocks from mycoplasmal contamination are described.     

Characterization of Rauscher murine leukemia virus envelope glycoprotein receptor in membranes from murine fibroblasts.

Plasma membrane preparations from KA31 (mouse) cells contained receptors for the binding of Rauscher murine leukemia virus (R-MuLV) envelope glycoprotein, gp70. This binding was demonstrated by gel filtration of a mixture of the microsomal fraction of the cells and 125I-labeled gp70. A rapid and convenient assay was developed to measure the complex formation between the membrane receptors and gp70 involving specific precipitation of the complex by 3 to 4% polyethylene glycol. The complex formation was responsive to the concentrations of both the receptor and gp70 and also to changes in temperature and pH. The gp70 binding was a noncooperative, saturable process, and an association constant of 3.5 X 10(8) M-1 was estimated from the binding data. The complex formation was reversible and a near-total exchange of 125I-labeled gp70 in the complex was achieved by incubation with excess of unlabeled gp70. The complex formation was inhibited by protein denaturing agents, guanidine-hydrochloride and urea. Pretreatment of the membrane fractions with either chymotrypsin or phospholipase C led to a loss of the membrane-associated receptor activity, indicating that a lipoprotein structure was important for the receptor function, consistent with the observation that nonionic detergents strongly inhibited the complex formation.     

Inhibition of human seminal fluid and Leishmania donovani phosphatases by molybdate heteropolyanions

Inhibition of a tartrate-resistant acid phosphatase (ACP) from Leishmania donovani and the tartrate-sensitive ACP from human seminal fluid (prostatic ACP) was examined using a series of 13 molybdate-containing heteropolyanions. The heteropolyanions were divided into four groups based on the number of molybdenum atoms they contain: Group I, Mo4; Group II, Mo6-8; Group III, Mo12; Group IV, Mo18. Two of the four groups, those consisting of compounds that contain either an Mo4 unit or an Mo18 unit with a heteroatom in the central cavity, were potent inhibitors and exhibited the highest degree of selectivity against the leishmanial and seminal fluid ACPs. The inhibition of prostatic ACP by complex E2 could be completely reversed by dialysis. Little inhibition of the acid phosphatase, beta-glucuronidase, or alpha-mannosidase from human spleen was observed with complexes B' and E2. For the seminal fluid phosphatase, the Ki values obtained with arsenate and vanadate depended markedly on pH, suggesting that, unlike most other phosphatases, the conformation of the inhibitor binding site on human seminal fluid ACP is pH-dependent. Results of competition experiments performed with various inhibitor pairs indicated that complex D2 binds to the active site of prostatic ACP while complex M binds at some site on the enzyme that affects the active site. Binding of complex M also modifies the affinity of the enzyme for other inhibitors such as vanadate. The potency of several heteropolyanion complexes and their selective inhibition of pathophysiologically significant acid phosphatases indicate that these compounds may have value as tools for study of the structure and function of this class of enzyme and perhaps in the therapy of human disease.     

Human immunodeficiency virus type 1 envelope gene structure and diversity in vivo and after cocultivation in vitro.

Nested-primer polymerase chain reaction (PCR) has been applied to the molecular cloning of 4.6-kb half-genome fragments of human immunodeficiency virus type 1 (HIV-1) taken directly from the peripheral blood mononuclear cells (PBMC) of an individual with neurological symptoms of HIV-1 infection. In a similar manner, gp120-coding portions of the envelope gene were cloned after PBMC from the same blood sample were cocultivated with uninfected PBMC for 28 days. The complete 1.6-kb nucleotide sequence of the gp120 gene was determined from each of 35 clones examined. Two of 13 (15%) PBMC-derived gp120 genes and 3 of 22 (14%) coculture-derived gp120 genes were defective as a result of frameshifts and an in-frame stop codon(s). Mean diversity between individual gp120-coding sequences in PBMC was fivefold greater (3.24%) than after coculture (0.65%). A predominant sequence of "strain" was found after coculture that was distinct from the diverse viral genotypes detected in vivo and therefore was selectively amplified during in vitro propagation. Multiple distinct third variable (V3) regions encoding the principal neutralizing domain of the envelope protein were detected in PBMC-derived genes, suggesting the presence of immunologic diversity of HIV env genes in vivo not reflected in the cocultured virus sample. The large size of the HIV fragments generated in this study will permit analysis of the diversity of immunologic reactivity, gene function, and pathogenicity of HIV genomes present within infected individuals, including the functional significance of the loss of diversity that occurs upon coculture.     

Effects of cytokines from activated immune cells on vascular cell growth and HIV-1 gene expression. Implications for AIDS-Kaposi's sarcoma pathogenesis.

Kaposi's sarcoma (KS) arises more frequently in homosexual and bisexual men than in other groups of HIV-1 infected individuals. Clinico-epidemiologic data indicate that homosexuals often are infected with multiple microbial agents and/or subjected to other antigenic stimuli, preceding or accompanying HIV-1 infection. Signs of immune activation, in fact, frequently have been detected in these individuals, and the onset of KS can precede any sign of immunodeficiency. These data have suggested that products from activated immune cells may affect the development of AIDS-KS. Here we report that conditioned media from activated or dysregulated T cells contain a variety of cytokines that promote the growth of spindle cells derived from KS lesions of AIDS patients (AIDS-KS cells) and induce normal vascular cells, potential cell progenitors of the AIDS-KS cells, to acquire features of the KS cell phenotype ("spindle" cell morphology and growth responsiveness to the mitogenic effect of extracellular HIV-1 Tat protein). The same conditioned media or cytokines promote HIV-1 gene expression and rescue defective HIV-1 proviruses, interrupting HIV-1 latency and increasing Tat production. The cellular and viral effects of cytokines are increased in an additive or synergistic manner by picomolar concentrations of extracellular Tat. These data suggest that cytokines produced by activated immune cells cooperate with HIV-1 infection in AIDS-KS pathogenesis.     

Psychophysical studies of the itch sensation and itchy skin ("alloknesis") produced by intracutaneous injection of histamine.

Psychophysical measurements of itch and itchy skin ("alloknesis"--itch produced by innocuous mechanical stimulation) were obtained in human volunteers following intracutaneous or subcutaneous injections of histamine or papain into the volar forearm. Histamine and papain were given in doses of 0.1, 1, or 10 micrograms in 10 microliters of saline. The effects of the depth of injection and of skin temperature on the latency, magnitude, and duration of itch were examined. Also, dose-response functions were obtained for the area of alloknesis produced by intracutaneous injections of histamine. Finally, the neural mechanisms underlying the spread of alloknesis were investigated via local anesthesia of the skin. Intracutaneous and subcutaneous injections of histamine, but not papain, produced a sensation of itch without pain. The latency of itch was shorter after an intracutanous than after a subcutaneous injection of histamine. The mean latencies of itch produced by a 1-microgram dose were 9.5 and 23.0 sec for intracutaneous and subcutaneous injections, respectively. No differences were observed in the magnitude or duration of itch. Similarly, the latency of itch was increased when the skin temperature at injection site was lowered to 15 degrees C, whereas the magnitude and duration of itch were unaffected. Intracutaneous and subcutaneous injections of histamine produced similar areas of alloknesis. However, the magnitude and duration of alloknesis were dependent on dose. The mean maximum areas of alloknesis produced by intracutaneous injections of 0.1, 1, and 10 micrograms of histamine were 28.3, 47.2, and 43.8 cm2, respectively. Alloknesis was present at 2 min after injection, increased to a maximum area without 10 min, and then gradually decreased during the next 25-40 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extracellular matrix of cultured glial cells: selective expression of chondroitin 4-sulfate by type-2 astrocytes and their progenitors

We have studied the extracellular matrix composition of cultured glial cells by immunocytochemistry with different monoclonal and polyclonal antibodies. Double immunofluorescence experiments and metabolic labeling with [3H]glucosamine performed in different types of cerebellar and cortical cultures showed that bipotential progenitors for type-2 astrocytes and for oligodendrocytes (recognized by the monoclonal antibody LB1 at early stages of their development) synthesize chondroitin sulfate (CS) and deposit this proteoglycan in their extracellular matrix. The distribution of the various [3H]glucosamine-labeled glycosaminoglycans between the intracellular and the extracellular space was different. CS was present both within the cells and in the culture medium, although in different amounts. Bi-potential progenitors became also O4-positive during their development in vitro. At the stage of O4-positivity they were still stained with antibodies against CS. However, when the progenitor cells were maintained in serum-free medium and differentiated into Gal-C-positive oligodendrocytes, they became CS-negative. In the presence of fetal calf serum in the culture medium, the bipotential progenitors differentiated into GFAP-positive type-2 astrocytes. These cells still expressed CS: their Golgi area and their surface were stained with anti-CS antibodies. Staining with monoclonal antibodies specific for different types of CS (4-sulfate, 6-sulfate, and unsulfated) revealed that both bipotential progenitors and type-2 astrocytes synthesized only chondroitin 4-sulfate. Type-1 astrocytes were negative for both the polyclonal and the monoclonal anti-CS antibodies. Finally, type-2 astrocytes and their progenitors were weakly stained with anti-laminin antibodies and unstained with anti-fibronectin. Type-1 astrocytes were positive for both anti-laminin and anti-fibronectin antibodies and appeared to secrete fibronectin in the extracellular space.