Responses of Calcicole and Calcifuge Poaceae Species to Iron-Limiting Conditions

Six differently distributed Poaceae species were compared in order to identify morphological and/or physiological properties that ensure calcicole species but not calcifuge species a sufficient Fe supply on CaCO₃ rich soils. When grown at a range of FeEDTA supply from deficient to adequate, the calcicole species had higher Fe productivities and relative yields at low Fe supply than the calcifuges. Specific root surface and Fe uptake requirements were lower in calcicoles than in calcifuges. Root exudation of Fe-mobilizing compounds was monitored in plants grown either with or without added FeEDTA in hydroponic culture. Under Fe deficiency, typically more than 80% of soluble root exudates of Poaceae are phytosiderophores (Marschner et al., 1989; Römheld, 1987). Maximum exudation rates of Fe mobilizing compounds were 6.6 to 11.5 μmol g^?1 root dry wt 2 hr^?1 in calcicoles and 0.48 to 1.64 in calcifuges. If Fe requirement is defined as mean Fe uptake rate required for 90 % of the maximal relative growth rate, the exudation rates of Fe mobilizing compounds were at least 11.7 to 31.9 times higher than Fe requirements in calcicoles and 0.38 to 5.36 times higher in calcifuges. Growth response to a precipitated versus a chelated Fe source was determined. The relative ability to grow with Fe(OH)₃ precipitate was correlated with the Fe mobilization rate of the species. The present results give evidence for the importance of Fe efficiency in wild plants. Calcicoles are able to live on calcareous soils partly because they produce larger amounts of Fe mobilizing compounds and have lower tissue Fe requirements than calcifuges.     

Jährliche Schwankungen der individuenzahl in einer Nordwestdeutschen Trockenen heide III

Summary The vegetation of a permanent quadrat situated in a Calluno-Genistetum typicum community has been analysed every year from 1955–1964 (cf. Vegetatio Vol. X, Fasc. 1, 1961 and Vol. XIII, Fasc. 4, 1966) and again from 1965 to 1969. Calluna vulgaris, which from 1955 to 1959 still covered 85–95% of the area, decreased to 30–55%. This was due to disease or perhaps was a result of sheep grazing. On the other hand,Betula pendula, which had appeared first in 1961, has increased continually in the permanent quadrat. This increase is probably due to the sheep, who avoid the young trees ofBetula pendula. The number and cover of the other palnts fluctuated due to variations in climate or the sheep grazing.      

A rat beta-interferon-induced mRNA: sequence characterization.

Polymerase chain reaction amplification of a cDNA derived from rat aortic smooth muscle cells, using sequences from conserved regions of the intramembrane domains of adrenergic receptors as primers, yielded the clone, rat8. This clone possesses a high degree of sequence similarity to a series of human interferon (IFN)-inducible genes. The rat8 sequence is 70% similar to that derived from the human alpha-IFN-induced gene, 9-27; there is 66% similarity between the deduced amino acid sequences encoded by the rat and the human genes. The rat homologue hybridizes with many bands in Southern analysis of rat DNA, suggesting that it is a member of a large multigene family.     

Hydrogen fluoride catalyzed migration of side chain protecting groups onto Fmoc during solid phase peptide synthesis. Characterization by CF-FAB analysis of carboxypeptidase digestions and NMR spectroscopy.

The solid-phase synthesis of the N alpha-Fmoc analog of protein kinase C substrate (PKCS, Lys-Arg-Ala-Lys-Ala-Lys-Thr-Thr-Lys-Lys-Arg) was characterized by low recovery from the resin and the concomitant appearance of four impurities. FAB-MS revealed molecular weights for two of these impurities that corresponded to the desired peptide plus Tos or Bzl. The other two were justified by invoking a CO2 elimination of the Clz protecting group to yield: 1) peptide plus 2-chlorobenzyl (ClBzl) and 2) peptide plus ClBzl and Tos. A CF-FAB analysis of carboxypeptidase digestions allowed observation of peptide cleavage down to an ion corresponding to lysine, Fmoc, and the corresponding protecting group(s). These data revealed that the impurities were not the result of incomplete deprotection but the result of migration of the protecting groups to the N-terminal end of the peptide. NMR experiments were subsequently performed and revealed the exact site of substitution: the meta positions of the N-terminal Fmoc. These impurities are presumed to arise by electrophilic aromatic substitution of the fluorene group during HF treatment. The desired Fmoc analog served as a convenient, albeit low-yielding, intermediate for purification of the highly charged PKCS by preparative self-displacement HPLC.     

Metorchis conjunctus (Cobbold, 1860) infection in wolves (Canis lupus), with pancreatic involvement in two animals

The trematode Metorchis conjunctus (Cobbold, 1860) was found in seven of 211 wolves from Saskatchewan which were examined between 1976 and 1983. The parasite caused cholangiohepatitis with periductular fibrosis in the liver of all the wolves, and chronic inflammation and fibrosis of the pancreas in two animals. The wolves with pancreatic involvement were emaciated. Five of the seven infected wolves were from one local area, and three of these were from a pack known to consume fish.