Isomerization of 4-O-methyl-D-glucuronic acid in neutral,aqueous solution

Aqueous solutions of 4-O-methyl-D-glucuronic acid at pH 7 were heated at 100°, and the monocarboxylic acids formed by isomerization were separated by anion-exchange chromatography and further identified by gas-liquid chromatography-mass spectrometry. After 6 h, the following yields of acids were obtained: 3-O-methyl-D-lyxo-5-hexulosonic (47%), 3-O-methyl-L-ribo-5-hexulosonic (12%), 4-O-methyl-D-mannuronic (4%), and 3-O-methyl-L-ribo-4-hexulosonic (1%).     

Separation of two forms of rabbit metallothionein by isoelectric focusing

Rabbits were given repeated injections of cadmium chloride. Cadmium- and zinc-containing protein fractions were obtained from the livers of these animals by precipitation procedures and Sephadex G-75 chromatography. The protein thus obtained showed several characteristics similar to those of the earlier described protein metallothionein. Further separation by isoelectric focusing showed two main protein peaks with isoelectric points at 3.9 and 4.5 respectively. Amino acid analysis of these two forms showed similar content of most amino acids [residues per cent.: cysteine (28%), aspartate (8%), threonine (5–6%), serine (12%), glycine (7%), alanine (13%), methionine (2%), isoleucine (2%)] but with a small difference in content of lysine (12 and 13% respectively), proline (9 and 5% respectively) and glutamate (2 and 4% respectively). The two forms of the protein both contained cadmium, but only the one with pI4.5 contained also significant amounts of zinc.     

Effect on Transpiration and Water Uptake by Rapid Changes in the Osmotic Potential of the Nutrient Solution

The sudden changes in the rates of transpiration and water uptake which occurred when the osmotic potential of the nutrient solution surrounding the roots of young wheat plants was rapidly changed were studied. The transpiration was measured by the aid of the microwave hygrometer and the water uptake by a recording poto-meter specially built for this investigation. When the osmotic potential of the nutrient solution was rapidly increased by adding mannitol, there was a temporary transpiration increase. The maximum increase was greater but the total time of the temporary increase shorter when a higher mannitol concentration was used. The quantity of water transpired by the shoots due to the temporary transpiration increase seemed to be fairly constant irrespectively of the mannitol concentration. The water transport to the shoots was immediately reduced when the osmotic potential was rapidly increased. The immediate reduction was greater when a higher mannitol concentration was used. After the immediate reduction the rate of water transport increased without delay. When the osmotic potential of the nutrient solution was rapidly decreased by withdrawing mannitol there was a temporary transpiration decrease, and the water transport to the shoots was immediately increased. After this increase the rate of water transport started to decrease at once. When, however, the mannitol concentration had been 0.30 M or higher, the transpiration rate increased progressively, and the change of the rate of water transport was small. The results indicate that the primary effect of the rapidly changed osmotic potential is localized to the root surface. The rapidly reduced water transport to the shoots after adding mannitol brings about the temporary transpiration increase. The course of events after withdrawing mannitol is just the reverse to that when adding mannitol.     

Pericarp structure of Leucas and related genera (Lamiaceae subfam. Lamioideae)

The pericarp has been studied in 72 taxa belonging to the genera Leucas, Leonotis, Acrotome, Otostegia and Isoleucas. Otostegia, Isoleucas and many Leucas (the Asiatic sections Astrodon, Leucas, Plagiostoma , and the African Spiculifolia, Squarrosicyme, Stachydiformis and Virgata ) have been found to agree with most other members of the subfamily Lamioideae by having high bone cells which contain crystals. Acrotome, Leonotis and most African Leucas (sections Hemistoma, Lasiocotys, Lonostoma, Neuflizeana, Ogadenia and Physoleucas ) deviate by having thin bone cells which often lack crystals, and due to their similarity, these African taxa are suggested to be closely related. The Asiatic Leucas (Ortholeucas), Plagiostoma and Astrodon also seem to form a group. Leucas milanjiana and perhaps also Leucas hyssopifolia are considered to be extraneous to Plagiostoma and to be more closely related to the section Leucas and the African Lasiocorys, Ogadenia and Physoleucas respectively.     

ABSORPTION OF NUTRIENTS AND PLANT GROWTH IN RELATION TO HYDROGEN ION CONCENTRATION

The absorption of nutrients depends to a large extent on the reaction of the substrate. At maximal growth the intake of salt is at minimum. Different ions are very differently affected. The intake of water is independent of the absorption of salts.     

In reply to hertwich & pease, Int. J. LCA 3 (4) 180 — 181, “ISO 14042 restricts use and development of impact assessment”

Life Cycle Impact Assessment describes indicators and does not predict actual impacts. The value of an LCA is its comprehensive review of all stages of a product’s life cycle and its synoptic view of all relevant environmental issues. The current version of the 14042 draft describes the uniqueness of Life Cycle Impact Assessment approach which is distinct from other assessment techniques. The wording was designed to help users of the standard understand how and why LCIA is distinct from other assessment methods. In closing, we would like to highlight our opinion that the present document on the level of a DIS is sound, stable and practical within the ISO 14040 series of standards. We do not agree withHertwich & Pease that the present document prevents the use of LCIA. It makes a choice regarding the exclusion of weighting across categories in order to prevent misuse in deriving inappropriate claims. And for characterisation it has achieved a well founded synthesis. In addition, we strongly believe that this standard will stimulate the international scientific discussion of LCA and will substantially contribute to enhanced and more valuable applications of LCA in the future.