Unusual bacteria from fungal material

Studies on mycorrhizal fungi of the genera Lactarius and Laccaria revealed bacteria, apparently present within the tissue of the sporocarps. Culture of these bacteria indicated that the predominant strains were of unusual colonial morphology. 10 strains were chosen for further study; these could be grown on plates of nitrogen-free medium for a number of subcultures, but did not fix nitrogen, using the acetylene reduction test. They produced copious amounts of extracellular polysaccharide of varying chemotypes.     

Unusual anthocyanins from the Epacridaceae

Cyanidin-3-xylosylarabinoside, cyanidin- and delphinidin-3-rhamnosylgalactoside and cyanidin-3-xylosylgalactoside have been identified during a survey     

Unusual diterpenes from Brickellia eupatoriedes

While the roots of Brickellia eupatoriedes contained several unusual rearranged pimarene derivatives, the aerial parts afrorded labdane derivatives     

Unusual characteristics of peritoneal macrophages from aged autoimmune-prone mice

Increasing concentrations of young or old mouse adherent peritoneal exudate cells (Y-PEC, O-PEC) have a different effect on the concanavalin A-induced proliferation of young (< 4 months) or old (>10 months) syngeneic mouse spleen cells (Y-SC, O-SC). Whereas the addition of NZB Y-SC to cultures of syngeneic Y-PEC resulted in a progressive suppression of the mitogenic response of Y-SC, the presence of similar concentrations of NZB O-PEC resulted in augmentation of that response which was significant (P < 0.05) at 20% PEC concentration. The NZB O-PEC also had a less suppressive effect on their O-SC. Similar but not as significant results (P < 0.1) were observed with cultures of O-PEC and Y-SC from BALB/c mice. In contrast, Y-PEC and O-PEC from seven other mouse strains substantially reduced the mitogenic response of both syngeneic Y-SC and O-SC. These observations could not be explained by differences in prostaglandin E₂ synthesis by the PEC or by crowded culture conditions. Our results suggest that either the population or the function of NZB peritoneal macrophages changes as the mouse ages and develops autoimmune disease.     

Unusual carbohydrate pattern in Trentepohlia species

Four Trentepohlia species and the related Cephaleuros virescens (Chroolepidaceae, Trentepohliales, Chlorophyceae) photosynthesize and accumulate mannitol, arabinitol, erythritol and glycerol, while Trentepohlia spp. additionally synthesize a second pentitol, ribitol (adonitol). T. umbrina also contains small amounts of a heptitol, volemitol.     

Unusual glycoconjugates in the oesophagus of a tilapine polyhybrid

The aim of this work is to elucidate the glycoconjugate composition of the secretory products of the oesophageal mucous cells in a tilapine polyhybrid. Lectin histochemistry gave evidence of the presence of β-galactose, α-N-acetylgalactosamine and sialic acid residues in the terminal position. The majority of sialic acid belongs to short side chains; a few sialic acid residues are acetylated at the C₇ and/or C₈ and/or C₉ level. The heterogeneity of the carbohydrate chains may mask potential receptor sites for micro-organisms and hamper the formation of multiple bonds.     

Unusual diterpenes and sesquiterpene xylosides from Nidorella hottentotica

The investigation of the South African species Nidorella hottentotica afforded in addition to known compounds several diterpene lactones, most of them being seco-labdanes with a ten-membered ring. Furthermore five unusual xylosides were isolated in which one or two derivatives of sesquilimonene were linked with the sugar. The structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomy of the genus is discussed briefly.     

Unusual Cu(III)—Schiff's base complexes

A new series of CU(III) complexes of the type [Cu(SB)]ClO₄, where SB is a dibasic tetradentate Schiff's base, were synthesized and characterized by elemental analysis, IR and electronic spectra. The prepared complexes are compared with Cu(II) complexes of the same ligands. The room temperature magnetic susceptibility and the x-band EPR spectra of the two types of complexes showed different behaviour. Cu(II) complexes were non conducting whereas Cu(III) complexes gave a conductance corresponding to 1:1 electrolyte. In fact this is the first report on the Cu(III) complexes with the tetradentate Schiff base ligands.     

Unusual kinetic behavior of Endothia parasitica protease in hydrolysis of small peptides

Endothia parasitica protease hydrolyzes l-leucyl-l-leucine amide and l-leucyl-l-phenylalanine amide at the peptide bond. l-Phenylalanyl-l-leticine amide, N-carbobenzoxy-l-leucyl-l-phenylalanine amide, N-carbobenzoxy-l-leucyl-l-pheml-alanine, N-carbobenzoxy-l-phenylalanyl-l-valine amide, and l-leucyl-β-naphthyl-amide are not hydrolyzed. In contrast to the kinetics of hydrolysis of casein and oxidized B-chain of insulin and activation of trypsinogen by Endothia parasitica protease which are normal, reaction progress curves for hydrolysis of l-leucyl-l-leucine amide and l-leucyl-l-phenylalanine amide are sigrnoidal. Initially, the reaction rates were of the order of 0.5–2.5% of the maximum rates eventually attained. With increasing time of incubation the reaction rates became faster and faster until maximum rates were achieved. This abnormal behavior was not eliminated by recrystallization of substrate or by incubation of enzyme alone or with products of the reaction prior to addition of substrate. Addition of a new aliquot of substrate, vizl-leucyl-l-leucine amide, to the reaction prior to complete hydrolysis of all of a previous aliquot of the same substrate, or reactions containing a mixture of oxidized B chain of insulin and l-leucyl-l-leucine amide, gave normal reaction progress curves. The duration of abnormal behavior before a maximum rate was attained was a function of enzyme concentration and temperature but not of substrate concentration even though substrate was in less than saturating amounts. The reaction data follow second-order autocatalytic kinetics with respect to enzyme concentration. It is proposed that most of the enzyme is in an inactive form in absence of substrate but is rapidly converted to the active form on combination with a good substrate such as trypsinogen, casein, or oxidized B chain of insulin. However, with a poor substrate such as l-leucyl-l-leucine amide, conversion to active enzyme is mediated through formation of an active enzyme-inactive enzyme complex followed by combination with substrate and hydrolysis.     

Unusual fungal niches

Fungi are found in all aerobic ecosystems, colonizing a diversity of substrates and performing a wide diversity of functions, some of which are not well understood. Many spices of fungi are cosmopolitan and generalists or habitats. Unusual fungal niches are habitats where extreme conditions would be expected to prevent the development of a mycobiota. In this review we describe five unusual fungal habitats in which fungi occupy poorly understood niches: Antarctic dry valleys, high Arctic glaciers, salt flats and salterns, hypersaline microbial mats and plant trichomes. Yeasts, black yeast-like fungi, melanized filamentous species as well as representatives of Aspergillus and Penicillium seem to be dominant among the mycobiota adapted to cold and saline niches. Plant trichomes appear to be a taxa. The advent of new sequencing technologies is helping to elucidate the microbial diversity in many ecosystems, but more studies are needed to document the functional role of fungi in the microbial communities thriving in these unusual environments.