Additions to the list of wild edible plants preservable by the deep freeze method

While the author (Gaertner 1962) has previously reported on the freezing, preservation and preparation of native wild plants of Ontario for culinary purposes, this communication concerns itself primarily with three common weeds: sow thistle (Sonchus spp.), evening primrose (Oenothera biennis L.) and sheep sorrel (Rumex acetosella L.), which might add to our winter diet. Two of the three plants are European introductions, usually considered extremely troublesome when present in the field; the third is a native biennial. In addition, the use of the unopened male cones of pine (Pinus spp.) and spruce (Picea spp.) are described.     

Binding of sugar phosphates, inositol phosphates and phosphorylated amino acids to actin.

Binding of biological phosphate compounds to actin was investigated by the effect of these compounds on the critical concentration of the pointed ends of gelsolin-capped actin filaments. According to this assay millimolar concentrations of glucose 6-phosphate and the bisphosphorylated sugars fructose 1,6-bisphosphate, fructose 2,6-bisphosphate, glucose 1,6-bisphosphate, sedoheptulose 1,7-bisphosphate and 2,3-bisphosphoglycerate were found to associate with actin. Glycerophosphoinositol phosphates bound to actin if they were present in millimolar concentrations, and if carbon atom 4 of the inositol ring was phosphorylated and carbon atom 5 was free of phosphate. Also phosphoserine and phosphotyrosine were found to interact with actin. Most of the actin-binding compounds stabilized actin filaments by decreasing the critical concentration suggesting that these compounds had a higher affinity for the subunits along actin filaments than for actin monomers. However, 2,3-bisphosphoglycerate and fructose 2,6-bisphosphate increased the critical concentration probably because these sugar phosphates bound to actin monomers thereby inhibiting actin polymerization.     

Barriers to ecosystem restoration presented by soil legacy effects of invasive alien N2‐fixing woody species: implications for ecological restoration

Impacts of invasive alien N₂‐fixing woody species and how they can persist as soil legacy effects after invasive species control are well appreciated, but how soil legacy effects can present barriers to restoration is poorly understood. Finding better ways to deal with these barriers to restoration is essential to improving restoration outcomes. In this study, we review 440 studies to identify barriers to restoration and potential management actions for the barriers to restoration, and provide practical application examples of the management actions. Our findings suggest that altered soil microbial communities, depleted native soil seed banks, elevated N status, secondary invasion and weedy native species dominance, and reinvasion are potential barriers to restoration. Furthermore, carbon addition, litter removal, soil microbial treatments, establishing species adapted to low N levels, prescribed burning, classical biological control, grazing, mowing, herbicide or graminicide application, manual weeding, soil N management, soil solarization, weed mats, native species reintroduction, and nurse plants are potential management actions for these barriers to restoration. However, there is little evidence suggesting that several of these barriers to restoration hinder improved restoration outcomes and this could be due to little research on them. More research is needed to assess their relative importance in hindering improved restoration outcomes. Management actions are rarely applied in combination, despite that they often address distinct barriers to restoration. Management actions should be combined into an integrated management effort to improve restoration outcomes.     

Einiges zur Kultur mariner niederer Pilze

A report is given on the facts known about cultivation of marine lower Phycomycetes on the basis of information from literature and own experience. The results of cultivation studies on subjects of the marineThraustochytrium aggregatum Ulken, the most common inhabitant of the waters of the North Sea, done at the Institut für Meeresforschung in Bremerhaven, are presented. The results show that the requirement of vitamin B₁₂, known from other members of the Thraustochytriaceae, is the same inT. aggregatum. On the other hand, the fungus needs a high concentration of soluble inorganic iron. Under these conditions the growth rate of the fungus increases three times more than normal, without changing the concentrations of the nutrients. These facts are discussed with regard to inorganic components from sewage waters.     

Isolation and characterization of an hydroxykynureninase from homogenates of adult mouse liver

A kynureninase-type enzyme was isolated from adult mouse liver. With kynurenine as the substrate, this enzyme has a K_m of 300 μ$\text{M}$; when the substrate is hydroxykynurenine, the K_m is 6 μ$\text{M}$. We conclude that this enzyme is an hydroxykynureninase. No enzyme which we could characterize as a kynureninase was found in this preparation. This suggests that tryptophan metabolism in the mouse occurs primarily through pathways that use hydroxykynurenine rather than kynurenine. Preliminary studies indicate that the enzyme is inhibited by its reaction product, hydroxyanthranilate, which is an intermediate in the synthesis of NAD. Such control of the hydroxykynureninase reaction may be of physiological importance in regulating the synthesis of NAD and/or in preventing the accumulation of hydroxyanthranilate, a putative carcinogen.     

Kinetics and specificity of serine proteases in peptide synthesis catalyzed in organic solvents

Initial rates of peptide-bond synthesis catalyzed by poly(ethylene glycol)-modified chymotrypsin in benzene were determined using high-performance liquid chromatography. Enzymatic synthesis of N-benzoyl-L-tyrosyl-L-phenylalanine amide from N-benzoyl-L-tyrosine ethyl ester and L-phenylalanine amide was found to obey Michaelis-Menten kinetics an to be consistent with a ping-pong mechanism modified by a hydrolytic branch. The catalytic activity of modified chymotrypsin was dependent on both water concentration and type of organic solvent, the highest synthesis rate being obtained in toluene. Since the chymotrypsin specificity in the organic phase was actually altered, the enzyme's apparent kinetic parameters were determined for different substrates and compared to those obtained with other serine proteases in benzene. Both N-benzoyl-L-tyrosine ethyl ester and N-alpha-benzoyl-L-lysine methyl ester were comparable acyl donors in benzene and the (kcat/Km)app value of modified chymotrypsin was only 10-fold smaller than that obtained with poly(ethylene glycol)-modified trypsin in the synthesis of N-alpha-benzoyl-L-lysyl-L-phenylalanine amide. The change in chymotrypsin specificity was also confirmed through the binding of trypsin inhibitors in benzene. The overall results suggest that hydrophobic bonding between the enzyme and its substrate should not be taken into account during catalysis in the organic phase. In general, if hydrophobic interactions are involved in the binding of substrates to the active site in aqueous media, the replacement of water by hydrophobic solvents will induce some change in enzyme specificity. Moreover, secondary residues of enzyme-binding sites may also exert a significant influence on specificity since, as observed in this study, chymotrypsin exhibited high affinity for cationic substrates and cationic inhibitors as well in apolar solvents.