Glycogen-storage disease in rats, a genetically determined deficiency of liver phosphorylase kinase.

Rats from an inbred strain (NZR/Mh) were found to have high concentrations of glycogen in their livers, even after 24 h of starvation. Despite this, blood glucose concentrations were well maintained on starvation for up to 72 h. The primary defect is a deficiency of liver phosphorylase kinase, causing a lack of active glycogen phosphorylase, although total phosphorylase is normal. The intravenous injection of glucagon caused a rapid activation of cyclic AMP-dependent protein kinase in the liver, but no increase in either phosphorylase kinase or phosphorylase a activity. Although total glycogen synthase activity in the livers of affected rats was higher than normal, glycogen synthase in the active form was very low, presumably as a result of the high liver glycogen content. The condition is transmitted as autosomal recessive and, apart from hepatomegaly, the affected rats appear healthy.     

Purification and characterization of dihydrobenzophenanthridine oxidase from elicited Sanguinaria canadensis cell cultures.

Upon treatment of Papaveracea cells with fungal elicitors, the biosynthesis of benzo[c]phenanthridine alkaloids is induced. Dihydrobenzophenanthridine oxidase, which catalyzes a later step in the biogenesis of these alkaloids, is one of the enzymes whose activity is elevated in the process. Here we report the 211-fold purification of the oxidase from elicited Sanguinaria canadensis by a combination of ammonium sulfate fractionation, DEAE-Sephadex, CM-Sephadex, Sephadex G-200, and either phenyl Superose or gel filtration chromatography. The purified enzyme utilized molecular oxygen to oxidize dihydrosanguinarine to sanguinarine with concomitant formation of hydrogen peroxide. A pH optimum of 7.0, Vmax of 27 nkat/mg protein, and apparent Km of 6.0 microM for dihydrosanguinarine were determined. Dihydrochelerythrine was also found to be a substrate for the purified enzyme, displaying an apparent Km of 10 microM. However, neither dihydronorsanguinarine nor the indole alkaloid ajmalicine was oxidized, indicating that the enzyme has some substrate specificity. Apparent molecular weight estimates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the most purified enzyme preparation obtained contained a major component of 77 kDa and two minor components between 59 and 67 kDa that can be associated with oxidase activity. Purified enzyme preparations possessed activity that was inhibited by sodium diethyldithiocarbamate, sodium azide, potassium cyanide, 1,4-DL-dithiothreitol, and mercaptoethanol.     

Gramene: development and integration of trait and gene ontologies for rice

Gramene (http://www.gramene.org/) is a comparative genome database for cereal crops and a community resource for rice. We are populating and curating Gramene with annotated rice (Oryza sativa) genomic sequence data and associated biological information including molecular markers, mutants, phenotypes, polymorphisms and Quantitative Trait Loci (QTL). In order to support queries across various data sets as well as across external databases, Gramene will employ three related controlled vocabularies. The specific goal of Gramene is, first to provide a Trait Ontology (TO) that can be used across the cereal crops to facilitate phenotypic comparisons both within and between the genera. Second, a vocabulary for plant anatomy terms, the Plant Ontology (PO) will facilitate the curation of morphological and anatomical feature information with respect to expression, localization of genes and gene products and the affected plant parts in a phenotype. The TO and PO are both in the early stages of development in collaboration with the International Rice Research Institute, TAIR and MaizeDB as part of the Plant Ontology Consortium. Finally, as part of another consortium comprising macromolecular databases from other model organisms, the Gene Ontology Consortium, we are annotating the confirmed and predicted protein entries from rice using both electronic and manual curation.     

Estuarine and habitat-related differences in growth rates of young-of-the-year winter flounder (Pseudopleuronectes americanus) and tautog (Tautoga onitis) in three northeastern US estuaries

Instantaneous growth rates of young-of-the-year winter flounder Pseudopleuronectes americanus (Walbaum) (12.0-60.4 mm standard length, SL) and tautog Tautoga onitis (Linnaeus) (21.4-73.8 mm total length, TL) from three estuarine systems in New Jersey (Great Bay-Little Egg Harbor and Navesink River) and Connecticut (Hammonasset River) were used in an attempt to assess the relative quality of selected nominal habitats. A series of short-term field caging experiments were conducted during 1994 and 1995 in: macroalgae (primarily, Ulva lactuca), eelgrass (Zostera marina), unvegetated areas adjacent to macroalgae and eelgrass and tidal creeks in Spartina dominated marsh. Growth rates varied with habitat, estuary and year. Comparisons across nominal habitats within and among estuaries did not show any one habitat with consistently higher growth, and growth was relatively independent of whether a habitat was vegetated or adjacent to vegetation. The growth rates of winter flounder and tautog from the Hammonasset River were not different among habitats in either year of the study. In the Great Bay-Little Egg Harbor, both winter flounder and tautog had higher growth rates in macroalgae with growth in eelgrass varying significantly between years. Conversely, in the Navesink River both species had higher growth rates in eelgrass. Environmental changes associated with temperature and dissolved oxygen appeared to influence growth rates. Winter flounder growth rate and survival was depressed in tidal marsh creeks in the three estuaries and in vegetated macroalgae habitats in the Navesink River where dissolved oxygen levels were often very low (<2 mgl(-1)) for extended periods. In summary, the growth rates of the young-of-the-year of these two species varied temporally and were dependent on the interaction of both the specific estuary and habitat in which the experiments took place. Further, habitat quality, as defined by relative growth rate, was difficult to evaluate because it can be variable and nominal habitat designations are often not sufficient to define the boundaries of a species habitat requirements.     

A rapidly activating delayed rectifier K+ current regulates pacemaker activity in adult mouse sinoatrial node cells

We have investigated the physiological role of the "rapidly activating" delayed rectifier K+ current (IKr) in pacemaker activity in isolated sinoatrial node (SAN) myocytes and the expression of mouse ether-a-go-go (mERG) genes in the adult mouse SAN. In isolated, voltage-clamped SAN cells, outward currents evoked by depolarizing steps (greater than -40 mV) were strongly inhibited by the class III methanesulfonanilide compound E-4031 (1-2.5 microM), and the deactivation "tail" currents that occurred during repolarization to a membrane potential of -45 mV were completely blocked. E-4031-sensitive currents (IKr) reached a maximum at a membrane potential of -10 mV and showed pronounced inward rectification at more-positive membrane potentials. Activation of IKr occurred at -40 to 0 mV, with half-activation at about -24 mV. The contribution of IKr to action potential repolarization and diastolic depolarization was estimated by determining the E-4031-sensitive current evoked during voltage clamp with a simulated mouse SAN action potential. IKr reached its peak value (approximately 0.6 pA/pF) near -25 mV, close to the midpoint of the repolarization phase of the simulated action potential, and deactivated almost completely during the diastolic interval. E-4031 (1 microM) slowed the spontaneous pacing rate of Langendorff-perfused, isolated adult mouse hearts by an average of 36.5% (n = 5). Expression of mRNA corresponding to three isoforms coded by the mouse ERG1 gene (mERG1), mERG1a, mERG1a', and mERG1b, was consistently found in the SAN. Our data provide the first detailed characterization of IKr in adult mouse SAN cells, demonstrate that this current plays an important role in pacemaker activity, and indicate that multiple isoforms of mERG1 can contribute to native SAN IKr.     

Influence of free air space on microbial kinetics in passively aerated compost

The influence of free air space (FAS) on passively aerated composting has been reported, but the quantitative relationship between FAS and the microbial kinetics in passively aerated compost has not been investigated. This relationship was studied by composting dairy manure and straw in an enclosed, passively aerated, cylindrical vessel. Based on this experimental system, conceptual and numerical models were developed in which the compost bed was considered to consist of layered elements, each being physically and chemically homogeneous. The microbial activity in each layer was represented in order to predict oxygen and substrate consumption and the release of water and heat. Convective transport of air, moisture, and heat through the layers was represented. Microbial growth and substrate consumption rates were described using modified first-order kinetics for each of the mesophilic and thermophilic temperature regimes. The values of the microbial kinetic parameters were adjusted for each layer based on an innovative, non-linear, statistical analysis of temperature histories recorded at different layers in the compost bed during three treatments (i.e., FAS values of 0.45, 0.52, and 0.65). Microbial kinetic rate constants were found to follow a sigmoid relationship with FAS, with correlation coefficients (R(2)) of 0.97 for the mesophilic stage and 0.96 for the thermophilic stage. Temperature histories and airflow measurements from a fourth treatment (FAS value of 0.57) were used as an independent check of the model's performance. Simulation results indicate that the model could predict the general trend of temperature development. A plot of the residuals shows that the model is biased, however, possibly because many parameters in the model were not measured directly but instead were estimated from literature. The result from this study demonstrates a new method for describing the relationship between microbial kinetics (k(max)) and substrate FAS, which could be used to improve the design, optimization, and management of passively aerated composting facilities.