Extracellular enzyme localization during interspecific fungal interactions

Abstract Confronted colonies of Phlebia radiata, P. rufa, Coriolus versicolor, Stereum hirsutum, Phanerochaete velutina and Hypholoma fasciculare showed spatially and temporally heterogeneous patterns of loccase-α-naphthol and peroxidase activities. These activities were coincident in axenic cultures. but were not always so during interaction. Confrontation between species resulted in induction of phenoloxidase activities, even within coenocytic colony regions of Phlebia species which were normally void of such activities in axenic culture. These events resulted in restriction of C. versicolor growth during interaction with P. rufa.     

Aerobic mineralization of vinyl chloride by a bacterium of the order Actinomycetales

A gram-positive branched bacterium isolated from a trichloroethylene-degrading consortium mineralized vinyl chloride in growing cultures and cell suspensions. Greater than 67% of the [1,2-14C]vinyl chloride was mineralized to carbon dioxide, with approximately 10% of the radioactivity appearing in cell biomass and another 10% appearing in 14C-aqueous-phase products.     

A comparison of net and gross rates of oxygen production as a function of light intensity in some natural plankton populations and in a Synechococcus culture

In vitrorates of gross and net oxygen production were measuredas a function of light intensity in some plankton communitiescollected from Bedford Basin, Nova Scotia, and in a monoclonalculture of Synechococcus. The rate of gross oxygen productionwas measured by a technique in which the stable oxygen isotope,¹⁸O, serves as a photosynthetic tracer Net oxygen productionwas measured by automated Winkler technique. The rate of communityrespiration in the light was then determined by the differencebetween gross and net rates of oxygen production. In the naturalpopulations examined, neither gross nor net oxygen productionrates were significantly inhibited at the highest light intensitymeasured (500–800 µE m^–2 s^–1) In a samplein which the dark respiration rate was small relative to themaximal rate of production [P_max;sensu Platt et al (1980) JMar. Res., 38, 687–701] the rates of ‘light’respiration were 3 times greater. In two other communities,with high rates of dark respiration relative to P_maxthe ratesof ‘light’ respiration were closer to rates of darkrespiration. In the Synechococcus clone, both gross and netoxygen production rates were inhibited at high light intensities.Rates of ‘light’ respiration were found to varyas a function of light intensity. The greatest rates of respirationwere measured in samples incubated at light intensities thatwere just saturating (100 µE m^–2 s^–1). Therates of ¹⁴C production were also measured as a function oflight intensity The photosynthetic quotients, based on ¹⁴C productionrates and gross oxygen production rates, average 1 9     

Structure and function of tyrosine kinase receptors

Over the past ten years, several growth factor receptors have been shown to be ligand-regulated tyrosine kinases. Tyrosine kinase activity is essential for signal transmission, suggesting that phosphorylation cascades may play an important role. Considerable effort has gone into understanding the structure and function of tyrosine kinase receptors in order to define their mechanisms of signal transmission. However, the protein substrates of the receptor kinases have proven to be difficult to isolate and clone. This review focuses on the receptors for insulin, epidermal growth factor, and platelet-derived growth factor. They are all tyrosine kinases, but emerging evidence suggests that they utilize multiple separate signal transduction pathways. Work carried out during the next several years should yield considerable insight into the complexity of the components which interact with these tyrosine kinase receptors to regulate cellular growth and metabolism.     

Isolation and characterization of a cDNA clone encoding the anti-viral protein from Phytolacca americana

Phytolacca anti-viral protein (PAP) was purified from Phytolacca leaves and the N-terminal was sequenced. A cDNA library was made from mRNAs isolated from Phytolacca leaves and cDNA clones for PAP were identified using oligonucleotide probes derived from the N-terminal amino acid sequence. The PAP-cDNA clone was sequenced from both directions. The predicted amino acid sequence of PAP was compared with the amino acid sequences of other ribosome-inactivating proteins. The identities of these proteins to PAP ranged from 29 to 38%, and a region was found in each with a sequence similar to the PAP sequence (AIQMVSEAARFKYI). Southern blot analysis indicates that PAP is encoded by a multi-gene family.Abbreviations MAP Mirabilis jalapa anti-viral protein - PAP Phytolacca anti-viral protein - SO6 30 kDa ribosome-inactivating protein from the seeds of Saponaria officinalis     

Murine erythrocyte ankyrin cDNA: highly conserved regions of the regulatory domain

Ankyrin is an essential link between cytoskeletal proteins, such as spectrin, and membrane bound proteins, such as protein 3, the erythrocyte anion exchanger. Although the amino acid structure of human ankyrin is known, the functional regions have been only partially defined. Sequence comparisons between mouse and human ankyrin offer one mechanism of identifying highly conserved regions that probably have functional significance. We report the isolation and sequencing of a series of overlapping murine erythroid ankyrin (Ank-1) cDNAs from spleen and reticulocyte libraries (total span 6238 bp) and identify potentially important regions of murine-human reticulocyte ankyrin homology. Comparison of the predicted peptide sequences of mouse and human erythroid ankyrins shows that these ankyrins are highly conserved in both the N-terminal, protein 3 binding domain (96% amino acid identity) and in the central spectrin-binding domain (97% identity), but differ in the C-terminal regulatory domain (79% identity). However, the C-terminal regulatory domain contains two regions of peptide sequence that are perfectly conserved. We postulate these regions are important in the regulatory functions of this domain.     

Attempted Transformation of Wheat (Triticum aestivum) and Tobacco (Nicotiana tabacum) by Plasmid DNA Uptake Via the Pollen-tube Pathway

Plasmid DNA (CaMVGUS, containing β-glucuronldase gene) was used to transform developing seed of wheat and tobacco through pollen-tube pathway. The DNA was applied on the ovule end of excised styles and stigmas of wheat and tobacco after pollination. None of the 272 wheat and 13,567 tobacco plants obtained after application of the isolated DNA showed β-glucuronidase activity suggesting that the pollen-tube pathway may not be effective for transformation of plants.