Roles of sulfate adsorption and base cation supply in controlling the chemical response of streams of western Virginia to reduced acid deposition

Micro-organisms are vital for the functioning of all food webs and are the major drivers of the global biogeochemical cycles. The microbial community compositions and physicochemical conditions of the different water masses in the North Sea, a biologically productive sea on the northwestern European continental shelf, were studied during two summer cruises, in order to provide detailed baseline data for this region and examine its microbial biogeography. For each cruise the stations were clustered according to their physicochemical characteristics and their microbial community composition. The largest cluster, which covered most of the central and northern North Sea, consisted of stations that were characterized by a thermally stratified water column and had low chlorophyll a autofluorescence and generally low microbial abundances. The second main cluster contained stations that were dominated by picoeukaryotes and showed the influence of influxes of North Atlantic water via the English Channel and south of the Shetland Islands. The third main cluster was formed by stations that were dominated by cyanobacteria and nanoeukaryotes in the reduced salinity Norwegian Coastal and Skagerrak waters, while the fourth cluster represented the German Bight, a region with strong riverine input, high nutrient concentrations, and consequently high heterotrophic bacterial and viral abundances. Despite the complex and dynamic hydrographic nature of the North Sea, the consistent distinctions in microbiology between these different hydrographic regions during both cruises illustrate the strong links between the microbial community and its environment, as well as the possibility to use microorganisms for long-term monitoring of environmental change.     

A NADPH-dependent (S)-imine reductase (SIR) from Streptomyces sp. GF3546 for asymmetric synthesis of optically active amines: purification, characterization, gene cloning, and expression

A NADPH-dependent (S)-imine reductase (SIR) was purified to be homogeneous from the cell-free extract of Streptomyces sp. GF3546. SIR appeared to be a homodimer protein with subunits of 30.5 kDa based on SDS-polyacrylamide gel electrophoresis and HPLC gel filtration. It also catalyzed the (S)-enantioselective reduction of not only 2-methyl-1-pyrroline (2-MPN) but also 1-methyl-3,4-dihydroisoquinoline and 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinoline. Specific activities for their imines were 130, 44, and 2.6 nmol?min^?1?mg^?1, and their optical purities were 92.7 % ee, 96.4 % ee, and >99 % ee, respectively. Using a NADPH-regenerating system, 10 mM 2-MPN was converted to amine with 100 % conversion and 92 % ee after 24 h. The amino acid sequence analysis revealed that SIR showed about 60 % identity to 6-phosphogluconate dehydrogenase. However, it showed only 37 % identity with Streptomyces sp. GF3587 (R)-imine reductase. Expression of SIR in Escherichia coli was achieved, and specific activity of the cell-free extract was about two times higher than that of the cell-free extract of Streptomyces sp. GF3546.     

FAM111A Mutations Result in Hypoparathyroidism and Impaired Skeletal Development

Kenny-Caffey syndrome (KCS) and the similar but more severe osteocraniostenosis (OCS) are genetic conditions characterized by impaired skeletal development with small and dense bones, short stature, and primary hypoparathyroidism with hypocalcemia. We studied five individuals with KCS and five with OCS and found that all of them had heterozygous mutations in FAM111A. One mutation was identified in four unrelated individuals with KCS, and another one was identified in two unrelated individuals with OCS; all occurred de novo. Thus, OCS and KCS are allelic disorders of different severity. FAM111A codes for a 611 amino acid protein with homology to trypsin-like peptidases. Although FAM111A has been found to bind to the large T-antigen of SV40 and restrict viral replication, its native function is unknown. Molecular modeling of FAM111A shows that residues affected by KCS and OCS mutations do not map close to the active site but are clustered on a segment of the protein and are at, or close to, its outer surface, suggesting that the pathogenesis involves the interaction with as yet unidentified partner proteins rather than impaired catalysis. FAM111A appears to be crucial to a pathway that governs parathyroid hormone production, calcium homeostasis, and skeletal development and growth.     

Components Contributing to the Improvement of Meat Taste during Storage

The changes in both taste and taste components of beef, pork, and chicken during storage were examined.

The brothy taste intensity of pork and chicken was significantly stronger after conditioning than before. On the other hand, for beef, there was no significant difference in the brothy taste intensity before or after conditioning. The analysis of major taste components showed that the levels of free amino acids in all meats were higher after conditioning than before. The differences in the levels of free amino acids before versus after conditioning were large in pork and chicken and very small in beef. Oligopeptide levels were lower in beef after conditioning than before, but they were higher in pork and chicken after conditioning than before. These results corresponded to results of the sensory evaluation studies described above, indicating that free amino acids and oligopeptides contributed to the improvement of meat taste during storage.     

Acid-Catalyzed Stereoselective Cyclization of Germacrene D

A monohalomethane-producing enzyme, S-adenosyl-L-methionine-dependent halide ion methyltransferase (EC 2.1.1.-) was purified from the marine microalga Pavlova pinguis by two anion exchange, hydroxyapatite and gel filtration chromatographies. The methyltransferase was a monomeric molecule having a molecular weight of 29,000. The enzyme had an isoelectric point at 5.3, and was optimally active at pH 8.0. The K_m for iodide and SAM were 12 mM and 12 μM, respectively, which were measured using a partially purified enzyme. Various metal ions had no significant effect on methyl iodide production, suggesting that the enzyme does not require metal ions. The enzyme reaction strictly depended on SAM as a methyl donor, and the enzyme catalyzed methylation of the I^-,Br^-, and Cl^- to corresponding monohalomethanes and of bisulfide to methyl mercaptan.     

Syntheses of Paromamine and Its Related Compounds

Paromamine and its related compounds were synthesized by a modified Königs-Knorr reaction of 3,4,6-tri-O-acetyl-2-(2′,4′-dinitroanilno)-α-d-glucopyranosyl bromide with isopropylidene derivatives of 2-deoxystreptamine, streptamine and dihydroconduramine F–4. The condensed products were isolated as their poly N-acetyl derivatives and proved to have α-configuration by PMR spectroscopy in D₂O.     

Studies on γ-Radiolysis of Sulfur Containing Amino Acids

In connection with flavor deterioration accompanied by food irradiation, the effect of γ-irradiation on sulfoxide amino acids in air free aqueous system was investigated. The major radiolysis products from S-n-propyl-l-cysteine sulfoxide (PCSO) were alanine, cysteic acid, dipropyl disulfide, etc., and from S-allyl-l-cysteine sulfoxide (ACSO) were S-allyl-l-cysteine, cystine, cysteic acid, etc., which were isolated chromatographycally and identified by using IR and mass spectrometry. The sulfoxide in ACSO was more easily reduced to sulfide than that of in PCSO, and the bond of S-C (β-carbon in alanine moiety) in ACSO was difficult to cleave. These differences observed between PCSO and ACSO in the radiolysis products and their yields indicate that the radiolysis degradation is considerably influenced by the structure of alkyl group. From the experiments with N₂O or KBr addition during irradiation, principal roles of the active species in irradiated water in the degradation processes were partly elucidated.     

Reconstitution of Human Casein Micelle and Its Properties

Human casein micelles were reconstituted from isolated κ- and β-caseins and calcium ions. Micelle formation was recognized in the presence of calcium chloride even at the low concentration of 5mM. At pH levels ranging from 5.5 to 8.0, the re-formed micelles were quite stable so that precipitation of β-casein was not observed. The large micelles were constituted by a higher ratio of β-casein to κ-casein (16:1 by weight) than the small micelles (3: 1). The κ-casein in the small micelles contained carbohydrates to about 43% (w/w) in the molecule, whereas that in the large micelles was only about 25%. When the casein micelles were re-formed from κ-easein and fractionated β-casein components, the extent of phosphorylation of the β-casein component was found to influence the micelle formation; i.e., the β-casein component with no phosphate (the 0-P form) was disadvantageous to form micelles, but the component with 5 phosphates (the 5-P form) formed micelles most easily.