Eight species ofPseudocyphellariaare recorded from mainland Ecuador viz., P. arvidssonii, P. aurata, P. bartlettii, P. clathrata, P. crocata, P. dozyana, P. encoensis and P. intricata, with taxa asterisked being new records for Ecuador. Pseudocyphellaria bartlettii andP. encoensis are also new records for northern South America, and P. dozyana is new to South America. A key is given, and details of anatomy, morphology, chemistry, distribution, ecology and taxonomy are discussed.

Random mutations in genes from disparate protein classes may have different distributions of fitness effects (DFEs) depending on different structural, functional, and evolutionary constraints. We measured the fitness effects of 156 single mutations in the genes encoding AraC (transcription factor), AraD (enzyme), and AraE (transporter) used for bacterial growth on l-arabinose. Despite their different molecular functions these genes all had bimodal DFEs with most mutations either being neutral or strongly deleterious, providing a general expectation for the DFE. This contrasts with the unimodal DFEs previously obtained for ribosomal protein genes where most mutations were slightly deleterious. Based on theoretical considerations, we suggest that the 33-fold higher average mutational robustness of ribosomal proteins is due to stronger selection for reduced costs of translational and transcriptional errors. Whereas the large majority of synonymous mutations were deleterious for ribosomal proteins genes, no fitness effects could be detected for the AraCDE genes. Four mutations in AraC and AraE increased fitness, suggesting that slightly advantageous mutations make up a significant fraction of the DFE, but that they often escape detection due to the limited sensitivity of commonly used fitness assays. We show that the fitness effects of amino acid substitutions can be predicted based on evolutionary conservation, but those weakly deleterious mutations are less reliably detected. This suggests that large-effect mutations and the fraction of highly deleterious mutations can be computationally predicted, but that experiments are required to characterize the DFE close to neutrality, where many mutations ultimately fixed in a population will occur.

This paper gives a presentation of ADP and AMP inhibition of phosphoglycerate kinase with MgATP2-and 3-phospho-~-glycerate as substrates at high and low Mg2+ concentrations and pH 7.8.The enzyme seems to contain at least two nucleotide binding sites, one presumably binding to MgATP2-and the other to ADP3-. The ADP3-binding site might bind MgADPl-also. AMP2-competes for the same form of the enzyme, probably the same site, as MgATP2-. ADP3-and MgADPl-are competive inhibitors and AMP-is a non-competitive inhibitor of 3-P-glycerate.Values of the inhibition constant, Ki, for ADP3-a t low Mg2+ level and MgADPI-a t high Mg2+ level are 0.2 and 0.02 d, respectively. The latter value is about ten times less than the expected Michaelis constant for corresponding substrate in the reverse reaction. Ki for AMP is about 2.0mM at both low and high Mg2+ concentrations but the inhibition is stronger at a high than at a low Mg2+ level, probably caused by conformational and/or other differences of the enzyme a t these two metal ion concentrations.The main catalytic reaction suits a pattern that is consistent with a rapid equilibrium random mechanism.A kinetic study of the mutual dependence of the effect of the two substrates of phosphoglycerate kinase, MgATP2-and 3-phospho-~-glycerate on the reaction velocity, showed [l] that this can be expressed as V (For definitions of symbols, see Materials and Methods). Evidence that the enzyme contains more than one binding site for each substrate was also obtained [I]. Product inhibition studies have been the basis for a discussion whether ATP and ADP as substrates are bound to the same site of the enzyme or not [2-41. Aiming to get a first characterization of the enzyme [2,4] the inhibition was studied only at one set of concentrations of the substrates and the inhibitor (product).The study presented here was undertaken to obtain a more detailed understanding of the relationships between the substrates and products. Such an investigation of inhibition by products and product homologues might also be helpful in determining if the catalytic mechanism involves ordered or random addition of the substrates to the enzyme [5].Unusual Abbrevktiona. 3-P-glycerate, 3-phospho-~-gly cerate.Enzymes. Phosphoglycerate kinase or ATP : 3-phospho-D-glycerate 1-phosphotransferase (EC 2.7.2.3); galactokinase or ATP : D-galactose 1-phosphotransferase (EC 2.7.1.6) ; glyceraldehydephosphate dehydrogenase or D-glyceraldehyde-3-phosphate : NAD oxidoreductase (EC 1.2.1.12). MATERIALS AND METHODS ReagentsCrystalline phosphoglycerate kinase from yeast was obtained from Boehringer Mannheim GmbH (Mannheim, Germany). The enzyme was pursed further by column electrophoresis and the main electrophoretic component IIB was used [6]. The reagents for measurement of the enzymic activity were obtained from Sigma Chemical Co. Only analytical grade reagents were used. Mg2+ was used as the chloride salt. Methods for removing contaminating metal ions were described earlier [7]. Activity NeasurementsThe activity of phosphoglycerate k...

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The new genus Degelia (Pannariaceae) is described to accommodate three primarily Southern Hemisphere taxa: D. gayana (Mont.) comb, nov., D. duplomarginata (P. James & Henssen) comb, nov., and D. durietzii sp. nov. A key to the species is given, with data on synonymy, morphology, anatomy, chemistry, habitat and distribution. Coccocarpia gayana var. melacarpina Nyl. is reduced to synonymy with Degelia gayana. Relationships of Degelia with genera in the Pannariaceae and Coccocarpiaceae are discussed. Degelia is distinguished from other genera in the Pannariaceae by periclinal arrangement of cells in the upper cortex, a lower cortex of 2–3 layers of thick-walled periclinal hyphae, and Scytonema as the phycobiont; and from genera in the Coccocarpiaceae by the structure and ontogeny of the apothecia. D. duplomarginata is known from New Zealand and Hawaii, D. durietzii from New Zealand and Tasmania and D. gayana from New Zealand, Tasmania, Australia, Chile and Tristan da Cunha.