Vegetative and edaphic characteristics on relic charcoal hearths in the Appalachian mountains

Relic charcoal hearths are prevalent throughout the Appalachian Mountains as reminders of the wood charcoal era and are evident today by the characteristics of forest stand structure, composition and understory vegetation. The importance of the soil resource to the stability and recovery of these anomalies in the plant community is not well understood. This study was conducted to compare forest floor and soil chemical properties, and vegetative characteristics on relic charcoal hearths to adjacent, non-hearth areas. Overstory tree cover and density was significantly lower on hearths than for adjacent areas. Overstory richness and diversity were consistently, but not significantly, lower on hearths, as were density and species richness of understory and ground vegetation. Little difference between hearth and adjacent forest floor properties was observed; however, soil calcium concentrations, pH. and percent carbon were higher on hearths, and phosphorus concentrations were generally lower. We discuss the effects of releasing large amounts of base-forming cations through repeated use of the hearths and the subsequent long-term effects on soil fertility and vegetative development.     

Subsets of sialylated, sulfated mucins of diverse origins are recognized by L-selectin. Lack of evidence for unique oligosaccharide sequences mediating binding

Previous studies have shown that the mucin-type polypeptidesGlyCAM-1, CD34, and MAdCAM-1 can function as ligands for L-selectinonly when they are synthesized by the specialized high-endothelialvenules (HEV) of lymph nodes. Since sialylation, sulfation,and possibly fucosylation are required for generating recognition,we reasoned that other mucins known to have such componentsmight also bind L-selectin. We show here that soluble mucinssecreted by human colon carcinoma cells, as well as those derivedfrom human bronchial mucus can bind to human L-selectin in acalcium-dependent manner. As with GlyCAM-1 synthesized by lymphnode HEY, 2–3 linked sialic acids and sulfation seem toplay a critical role in generating this L-selectin binding.In each case, only a subset of the mucin molecules is recognizedby L-selectin. Binding is not destroyed by boiling, suggestingthat recognition may be based primarily upon carbohydrate structures.Despite this, O-linked oligosaccharide chains released fromthese ligands by beta-elimination do not show any detectablebinding to L-selectin. Following protease treatment of the ligands,binding persists in a subset of the resulting fragments, indicatingthat specific recognition is determined by certain regions ofthe original mucins. How ever, O-linked oligosaccharides releasedfrom the subset of non-binding mucin fragments do not show verydifferent size and charge profiles compared to those that dobind. Furthermore, studies with polylactosamine-degrading endoglycosidasessuggest that the core structures involved in generating bindingcan vary among the different ligands. Taken together, thesedata indicate that a single unique oligosaccharide structuremay not be responsible for high-affinity binding. Rather, diversemucins with sialylated, sulfated, fucosylated lactosamine-typeO-linked oligosaccharides can generate high-affinity L-selectinligands, but only when they present these chains in unique spacingand/or clustered combinations, presumably dictated by the polypeptidebackbone. L-selectin mucins sialic sialic acid sulfate adhesion     

The polyamine-derived amino acid hypusine: its post-translational formation in eIF-5A and its role in cell proliferation

Summary The unusual amino acid hypusine [N -(4-amino-2-hydroxybutyl)lysine] is a unique component of one cellular protein, eukaryotic translation initiation factor 5A (eIF-5A, old terminology, eIF-4D). It is formed posttranslationally and exclusively in this protein in two consecutive enzymatic reactions, (i) modification of a single lysine residue of the eIF-5A precursor protein by the transfer of the 4-aminobutyl moiety of the polyamine spermidine to its-amino group to form the intermediate, deoxyhypusine [N -(4-aminobutyl)lysine] and (ii) subsequent hydroxylation of this intermediate to form hypusine. The amino acid sequences surrounding the hypusine residue are strictly conserved in all eukaryotic species examined, suggesting the fundamental importance of this amino acid throughout evolution. Hypusine is required for the activity of eIF-5Ain vitro. There is strong evidence that hypusine and eIF-5A are vital for eukaryotic cell proliferation. Inactivation of both of the eIF-5A genes is lethal in yeast and the hypusine modification appears to be a requirement for yeast survival (Schnier et al., 1991 [Mol Cell Biol 11: 3105–3114]; Wöhl et al., 1993 [Mol Gen Genet 241: 305–311]). Furthermore, inhibitors of either of the hypusine biosynthetic enzymes, deoxyhypusine synthase or deoxyhypusine hydroxylase, exert strong anti-proliferative effects in mammalian cells, including many human cancer cell lines. These inhibitors hold potential as a new class of anticancer agents, targeting one specific eukaryotic cellular reaction, hypusine biosynthesis.     

L-Tryptophan: Biochemical,nutritional and pharmacological aspects

Summary Tryptophan is important both for protein synthesis and as a precursor of niacin, serotonin and other metabolites. Tryptophan is an unusual amino acid because of the complexity of its metabolism, the variety and importance of its metabolites, the number and diversity of the diseases it is involved in, and because of its use in purified form as a pharmacological agent. This review covers the metabolism of tryptophan, its presence in the diet, the disorders associated with low tryptophan levels due to low dietary intake, malabsorption, or high rates of metabolism, the therapeutic effects of tryptophan and the side effects of tryptophan when it is used as a drug including eosinophilia myalgia syndrome.     

Cell separation from high cell density broths of Alcaligenes eutrophus by using a coagulant

Summary Alcaligenes eutrophus was successfully recovered from high cell density broths by pre-treatment with polyaluminium hydroxide chloride silicate as a coagulant at 36–90 mg Al/l. The optimum pH range for cell coagulation was 10–12. Subsequent centrifugation (45×g) and filtration (pore size 0.5 mm) gave a cell recovery of higher than 90%. The energy demand for cell recovery with the coagulant was only 3–11% of that without it.     

Flow cytometric analysis of antibody producing cells using double immunofluorescent staining

Summary Double fluorescent labeling, with fluorescein isothiocyanate (FITC)-labeled F(ab)₂ specific for the heavy chain and R-phycoerythrin (R-PE)-labeled F(ab)₂ specific for the light chain, was demonstrated as a convenient means for the accurate evaluation of a heterogeneous non-antibody-producing population. Furthermore, it could be used for monitoring the changes in each immunoglobulin (Ig) chain content of the cells during the batch culture, which will facilitate the study on antibody synthesis, assembly and secretion.     

Biological species ofArmillaria and their mycoparasitic associations withRhodophyllus abortivus in Hokkaido

Specimens of basidiomes and/or rhizomorphs ofArmillaria mellea complex and basidiomes ofRhodophyllus abortivus, developing on the same decaying stumps or stems of forest trees, were collected in three forests in Hokkaido. Normal basidiomes ofR. abortivus were found near to, but free from, the rhizomorphs and/or basidiomes ofArmillaria, while abnormal basidiomes, as carpophoroid forms, were developed on the rhizomorphs ofArmillaria. Of three mycoparasiticArmillaria isolates found withR. abortivus, one was identified asA. gallica and two asA. jezoensis. The isolates ofR. abortivus showed excellent mycelial growth and rhizomorph formation on PDA. However, on MDA, RMDA and BMDA, they showed poor aerial mycelia growth and no rhizomorphs. In the contrapositional cultures, the growth ofA. gallica was completely inhibited byR. abortivus on PDA but only slightly inhibited on MDA and RMDA. On the other hand, mutual inhibition at a distance was observed on BMDA. The mycelial growth and rhizomorph formation inA. jezoensis were severely inhibited by the colony ofR. abortivus on PDA, but only slightly inhibited on MDA. On RMDA and BMDA, the colonies of twoArmillaria species andR. abortivus showed mutual inhibition at a distance and apparent rhizomorph formation by bothArmillaria species.     

Rice cationic peroxidase accumulates in xylem vessels during incompatible interactions with Xanthomonas oryzae pv oryzae.

A cationic peroxidase, PO-C1 (molecular mass 42 kD, isoelectric point 8.6), which is induced in incompatible interactions between the vascular pathogen Xanthomonas oryzae pv oryzae and rice (Oryza sativa L.), was purified. Amino acid sequences from chemically cleaved fragments of PO-C1 exhibited a high percentage of identity with deduced sequences of peroxidases from rice, barley, and wheat. Polyclonal antibodies were raised to an 11-amino acid oligopeptide (POC1a) that was derived from a domain where the sequence of the cationic peroxidase diverged from other known peroxidases. The anti-POC1a antibodies reacted only with a protein of the same mobility as PO-C1 in extracellular and guttation fluids from plants undergoing incompatible responses collected at 24 h after infection. In the compatible responses, the antibodies did not detect PO-C1 until 48 h after infection. Immunoelectron microscopy was used to demonstrate that PO-C1 accumulated within the apoplast of mesophyll cells and within the cell walls and vessel lumen of xylem elements of plants undergoing incompatible interactions.     

The stability of L-ATC hydrolase participating in L-cysteine production

Summary In the production of L-cysteine from D,L-ATC stability of the relevant enzymes produced byPseudomonas sp. was tested, and strategies to improve the stability of L-ATC hydrolase were investigated in view of water activity and ionic strength. Among the three enzymes which participate in L-cysteine production, i.e., ATC racemase, L-ATC hydrolase, and S-carbamyl-L-cysteine hydrolase, L-ATC hydrolase is the least stable. Various mixtures of salts and sorbitol were added to adjust the water activities of the tested solutions. As water activity decreased from 0.93 to 0.80, the stability of L-ATC hydrolase was sharply enhanced. In the absence of sorbitol the stability of L-ATC hydrolase increased in proportion to ionic strength. Even though enzyme stability was not good at a low ionic strength, it was enhanced by lowering water activity with addition of sorbitol. The half life of L-ATC hydrolase in sorbitol-salt mixtures increased by tenfold to twentyfold compared to that of a control.