Delimitation of the maritime boundary in the gulf of Maine area

The compulsory dispute settlement regime included in the 1982 Law of the Sea Convention is recognized as one of the most comprehensive in a modern international convention. Yet, in the recent application of this regime, the question has arisen as to whether the procedural prerequisites associated with the LOS Convention's compulsory dispute settlement mechanism are so arduous as to avoid binding and compulsory jurisdiction in most instances. This article addresses that question by examining, in particular, the reasoning of the Southern Bluefin Tuna arbitration tribunal, which found Article 281 of Section 1 of the LOS Convention to bar jurisdiction to the compulsory dispute settlement mechanism prescribed by the Convention, and offers suggestions as to how states might distinguish or overcome the barriers imposed by the Southern Bluefin Tuna tribunal in future cases.     

Deriving metabolic engineering strategies from genome-scale modeling with flux ratio constraints

Optimized production of bio-based fuels and chemicals from microbial cell factories is a central goal of systems metabolic engineering. To achieve this goal, a new computational method of using flux balance analysis with flux ratios (FBrAtio) was further developed in this research and applied to five case studies to evaluate and design metabolic engineering strategies. The approach was implemented using publicly available genome-scale metabolic flux models. Synthetic pathways were added to these models along with flux ratio constraints by FBrAtio to achieve increased (i) cellulose production from Arabidopsis thaliana; (ii) isobutanol production from Saccharomyces cerevisiae; (iii) acetone production from Synechocystis sp. PCC6803; (iv) H₂ production from Escherichia coli MG1655; and (v) isopropanol, butanol, and ethanol (IBE) production from engineered Clostridium acetobutylicum. The FBrAtio approach was applied to each case to simulate a metabolic engineering strategy already implemented experimentally, and flux ratios were continually adjusted to find (i) the end-limit of increased production using the existing strategy, (ii) new potential strategies to increase production, and (iii) the impact of these metabolic engineering strategies on product yield and culture growth. The FBrAtio approach has the potential to design “fine-tuned” metabolic engineering strategies in silico that can be implemented directly with available genomic tools.     

Representation of target-bound drugs by computed conformers: implications for conformational libraries

Background  

The increasing number of known protein structures provides valuable information about pharmaceutical targets. Drug binding sites are identifiable and suitable lead compounds can be proposed. The flexibility of ligands is a critical point for the selection of potential drugs. Since computed 3D structures of millions of compounds are available, the knowledge of their binding conformations would be a great benefit for the development of efficient screening methods.     

Influence of Calcium on Formation and Reduction of Protochlorophyllide in the Pigment Mutant C-2A' of Scenedesmus obliquus

The levels of protochlorophyllide and protochlorophyll of pigmentmutant C-2A' of Scenedesmus obliquus grown in darkness dependupon the calcium concentration in the growth medium. In thepresence of calcium both the protochlorophyllide and protochlorophylllevels decrease upon irradiation whereas the amount of photoreducedchlorophyllide increases. In contrast to light-dependent protochlorophyllide reduction,the activity of light-independent protochlorophyllide reductionis higher in calcium free cultures compared to those grown inthe presence of calcium. It is discussed whether calcium actsdirectly on the activity of the protochlorophyllide oxidoreductaseor stabilizes the newly formed chlorophyllide. (Received September 1, 1989; Accepted February 19, 1990)     

Carbohydrate uptake in Advenella mimigardefordensis strain DPN7T is mediated by periplasmic sugar oxidation and a TRAP‐transport system

In this study, we investigated an SBP (DctP_Am) of a tripartite ATP‐independent periplasmic transport system (TRAP) in Advenella mimigardefordensis strain DPN7^T. Deletion of dctP_Am as well as of the two transmembrane compounds of the tripartite transporter, dctQ and dctM, impaired growth of A. mimigardefordensis strain DPN7^T, if cultivated on mineral salt medium supplemented with d ‐glucose, d ‐galactose, l ‐arabinose, d ‐fucose, d ‐xylose or d ‐gluconic acid, respectively. The wild type phenotype was restored during complementation studies of A. mimigardefordensis ΔdctP_Am using the broad host vector pBBR1MCS‐5::dctP_Am. Furthermore, an uptake assay with radiolabeled [¹⁴C(U)]‐d ‐glucose clearly showed that the deletion of dctP_Am, dctQ and dctM, respectively, disabled the uptake of this aldoses in cells of either mutant strain. Determination of K_D performing thermal shift assays showed a shift in the melting temperature of DctP_Am in the presence of d ‐gluconic acid (K_D 11.76 ± 1.3 µM) and the corresponding aldonic acids to the above‐mentioned carbohydrates d ‐galactonate (K_D 10.72 ± 1.4 µM), d ‐fuconic acid (K_D 13.50 ± 1.6 µM) and d ‐xylonic acid (K_D 8.44 ± 1.0 µM). The sugar (glucose) dehydrogenase activity (E.C.1.1.5.2) in the membrane fraction was shown for all relevant sugars, proving oxidation of the molecules in the periplasm, prior to transport.     

Ovarian response to resource availability in female Rhagoletis indifferens

Fitness trade‐offs in behavioural ecology theory suggest that the costs associated with dispersal can impact reproductive output, but evidence of dispersal‐reproduction trade‐offs is often lacking. We present evidence of Rhagoletis indifferens Curran (Diptera: Tephritidae) developing its egg load in response to host availability [Prunus avium L. (Rosaceae)] and link this to our previous work on flight behaviour through the common methodology of these two studies. We replicated the study design from the flight mill experiment, such that females were maintained in one of six possible treatments combining two factors: social interactions (crowded vs. isolated) and resources (food = food only; leaf = food + leaf; and cherry = food + leaf + fruit), and then dissected the females to determine egg load. Egg counts varied significantly with ‘crowded’ females and those in the ‘cherry’ resource treatments producing the most mature eggs. Although the average mature egg count for females from the ‘leaf’ and ‘food’ resource treatments was similar, these two groups differed in the proportion of females that produced no mature eggs at all. No significant interaction terms between the factors tested were generated. We conclude that the effect of social interactions and resources on the maturation of eggs is additive in R. indifferens. These results support those of an earlier flight mill experiment and provide evidence that egg load may trade off with dispersal ability in R. indifferens.     

Chromatographic separation of (E)- and (Z)-isomers of entacapone and their simultaneous quantitation in human plasma by LC–ESI-MS/MS

A selective, sensitive and high throughput liquid chromatography–tandem mass spectrometry (LC–ESI-MS/MS) method has been developed and validated for the chromatographic separation and quantitation of (E)-entacapone and (Z)-entacapone in human plasma. Sample clean-up involved liquid–liquid extraction (LLE) of both the isomers and carbamazepine used as internal standard from 500 μL of human plasma. Both the analytes were chromatographically separated with a resolution factor of 3.0 on a Gemini C18 (50 mm × 4.6 mm, 5 μm particle size) analytical column using 1% formic acid and methanol (50:50, v/v) as the mobile phase. The selectivity factor (α) of the column for the separation was 2.0, based on the capacity factors of 2.6 and 1.3 for (E)- and (Z)-isomers respectively. The parent → product ion transitions for both the isomers (m/z 306.1 → 233.0) and IS (m/z 237.3 → 194.2) were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) and positive ion mode. The method was validated over the concentration range of 24.3–6076 ng/mL and 23.8–5960 ng/mL for (E)-entacapone and (Z)-entacapone respectively. Matrix effect was assessed by post-column analyte infusion experiment and the process/extraction efficiency found was 94.3% and 89.3% for (E)- and (Z)-isomers respectively. The method was successfully applied to a pivotal bioequivalence study in 36 healthy human subjects after oral administration of 200 mg (E)-entacapone tablet formulation under fasting conditions.