Putrescine Influences Growth and Production of Coumarins in Hairy Root Cultures of Witloof Chicory (Cichorium intybus L. cv. Lucknow Local)

The effect of putrescine (Put) on the growth and production of two coumarins, esculin and esculetin, in hairy roots of chicory (Cichorium intybus L. cv. Lucknow local) was examined. To study the role of Put on growth and production of coumarins, polyamine inhibitors, namely α-dl-difluromethylornithine and α-dl-difluromethylarginine were used at 1 mM concentration. Put treatment at 1.5 mM produced a 1.9-fold increase in the growth of hairy roots, as well as the production of esculin and esculetin. The treatments with polyamine (PA) inhibitors resulted in much lower growth and production of coumarins compared with both 1.5-mM Put treatment and the control. Both free and conjugated PAs were studied over the whole culture period, and conjugates of all three PAs, namely Put, spermidine, and spermine, were higher than free PAs throughout the culture period. The treatments with PA inhibitors showed lower levels of endogenous PAs compared with Put-treated samples. The treatment with 1.5 mM Put showed maximum accumulation of endogenous conjugated Put (2,098 ± 157 nmoles gm⁻¹ fresh weight). The production of esculin and esculetin was strictly correlated with growth in all treatments. Put at 1.5 mM resulted in greater length of primary root (18.3 ± 1.4 cm) as compared with the control (11 ± 0.9 cm) and larger numbers of secondary and tertiary roots. Received July 14, 1999; accepted October 5, 1999     

Heterochromatin: RNA points the way

Mutation of the multi-KH domain protein DPP1, which has single-stranded nucleic acid binding activity, suppresses heterochromatin-mediated silencing in Drosophila; it also disrupts the modification of histone H3 at lysine 9, and association of heterochromatin protein 1 on the heterochromatic regions, suggesting a role for DDP1 in heterochromatin formation.     

Adenoid cystic carcinoma of the external auditory canal. A case report with diagnosis by fine needle aspiration

BACKGROUND: Although the cytologic findings of adenoid cystic carcinoma have been reported frequently, fine needle aspiration diagnosis of adenoid cystic carcinoma of the external auditory canal has not been reported before in the English-language literature. CASE: A 70-year-old female presented with a mass occluding the external auditory canal. Fine needle aspiration cytology was performed. The smears showed hyaline globules surrounded by tumor cells. The tumor cells had uniform, round, hyperchromatic nuclei, visible nucleoli and little cytoplasm. Based on these cytomorphologic features, diagnosis of adenoid cystic carcinoma was rendered and then confirmed by histopathologic examination. CONCLUSION: This is the first cytologic report of adenoid cystic carcinoma of the external auditory canal, a rare site for this tumor.     

Structure-function relationships of the RNA-dependent RNA polymerase from poliovirus (3Dpol). A surface of the primary oligomerization domain functions in capsid precursor processing and VPg uridylylation

The primary oligomerization domain of poliovirus polymerase, 3Dpol, is stabilized by the interaction of the back of the thumb subdomain of one molecule with the back of the palm subdomain of a second molecule, thus permitting the head-to-tail assembly of 3Dpol monomers into long fibers. The interaction of Arg-455 and Arg-456 of the thumb with Asp-339, Ser-341, and Asp-349 of the palm is key to the stability of this interface. We show that mutations predicted to completely disrupt this interface do not produce equivalent growth phenotypes. Virus encoding a polymerase with changes of both residues of the thumb to alanine is not viable; however, virus encoding a polymerase with changes of all three residues of the palm to alanine is viable. Biochemical analysis of 3Dpol derivatives containing the thumb or palm substitutions revealed that these derivatives are both incapable of forming long fibers, suggesting that polymerase fibers are not essential for virus viability. The RNA binding activity, polymerase activity, and thermal stability of these derivatives were equivalent to that of the wild-type enzyme. The two significant differences observed for the thumb mutant were a modest reduction in the ability of the altered 3CD proteinase to process the VP0/VP3 capsid precursor and a substantial reduction in the ability of the altered 3Dpol to catalyze oriI-templated uridylylation of VPg. The defect to uridylylation was a result of the inability of 3CD to stimulate this reaction. Because 3C alone can substitute for 3CD in this reaction, we conclude that the lethal replication phenotype associated with the thumb mutant is caused, in part, by the disruption of an interaction between the back of the thumb of 3Dpol and some undefined domain of 3C. We speculate that this interaction may also be critical for assembly of other complexes required for poliovirus genome replication.     

Factors affecting growth of cell suspension cultures of hypericum perforatum L. (St. John's wort) and production of hypericin

Summary Use of Hypericum perforatum L., commonly known as St. John's wort, has increased recently due to the pharmaceutical potential of hypericin, found in its leaves. Hypericin has been reported to effect a natural treatment for mild and moderate depression by increasing the concentration of neurotransmitters in the central nervous system. We have developed a novel cell culture system for in vitro growth and production of this species, suggesting a possible technology for large-scale production of hypericin. Leaf explants grown in Murashige and Skoog salts supplemented with 2,4-dichlorophenoxyacetic acid (0.90 μM) and kinetin (0.11 μM) gave maximum percentage callus formation compared to other medium treatments evaluated. Hypericin localization in cell phase and leaves was found to vary, with cell phase accumulating hypericin in special organelles and leaves accumulating it in vacuoles. Light and dark conditions, with cell aggregate size, played important roles in growth and hypericin production in cell suspension cultures.     

Exudation of fluorescent beta-carbolines from Oxalis tuberosa L roots

Root fluorescence is a phenomenon in which roots of seedlings fluoresce when irradiated with ultraviolet (UV) light. Soybean (Glycine max) and rye grass (Elymus glaucus) are the only plant species that have been reported to exhibit this occurrence in germinating seedling roots. The trait has been useful as a marker in genetic, tissue culture and diversity studies, and has facilitated selection of plants for breeding purposes. However, the biological significance of this occurrence in plants and other organisms is unknown. Here we report that the Andean tuber crop species Oxalis tuberosa, known as oca in the highlands of South America, secretes a fluorescent compound as part of its root exudates. The main fluorescent compounds were characterized as harmine (7-methoxy-1-methyl-beta-carboline) and harmaline (3, 4-dihydroharmine). We also detected endogenous root fluorescence in other plant species, including Arabidopsis thaliana and Phytolacca americana, a possible indication that this phenomenon is widespread within the plant kingdom.     

Fine needle aspiration cytology of bursal cyst

OBJECTIVE: To evaluate the cytomorphology of bursal cyst and assess the efficacy of aspiration cytology in its diagnosis and treatment. STUDY DESIGN: Nineteen cases of bursal cyst seen over four years were studied. Material was obtained by fine needle aspiration. The smears were stained with May-Grünwald-Giemsa stain and hematoxylin and eosin. RESULTS: Eight cysts were in the popliteal fossa, 4 on the elbow, 3 on the knee, 2 on the shoulder and 2 in the calf. Gelatinous material was aspirated in all the cases. In some cases the cyst collapsed after aspiration. The key diagnostic features were hypocellular smears in a mucoid background. Histiocytelike (synovial) cells were seen lying in all cases and as pseudopapillary structures in two. CONCLUSION: The presence of a cyst at a classic location with aspiration of gelatinous material and the presence of singly occurring histiocytelike cells in a mucoid background in smears is diagnostic of bursal cyst. The procedure is therapeutic in some cases.