DETERMINATION OF GUSTATORY SUCROSE THRESHOLD IN WATER BY USE OF A LINEAR SUCROSE GRADIENT

A novel experimental method was developed which allows the determination of the threshold concentration of sucrose by use of a linear sucrose gradient in water. With this method a continuous tasting of the test-liquid is possible. A panel of 15 persons experienced in taste-testing was used. Three gradients of different steepness were applied: 0 to 1.5% (w/w) sucrose in 2 min (I), 3 min (II) and 4 min (III). The results of the new method were compared with those of the standard method (DIN). With gradients I and II we found values which were significantly higher than those of the standard method (I: 0.49% (w/w); II: 0.46% (w/w); DIN: 0.31% (w/w)), whereas with gradient III the same threshold value was found as with the DIN-Method (III: 0.32% (w/w)).     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Nuclear and cytoplasmic binding components for vitamin D metabolites.

Specific binding of 1α,25-dihydroxyvitamin D₃ to macromolecular components of small intestinal nuclei and cytosol is demonstrated. The nuclear 1α,25-dihydroxyvitamin D₃ complex can be extracted from chromatin by 0.3 M KCl and sediments at 3.7S in sucrose density gradients. The cytoplasmic 1α,25-dihydroxyvitamin D₃-binding components also sediment at 3.7S, identically to the nuclear complex under the ultracentrifugation procedures employed.Macromolecular binding components with a high affinity for 25-hydroxyvitamin D₃ (K_d = 4.5 × 10⁻⁹ M) were also identified in intestinal cytosol which differ from the 1α,25-hydroxyvitamin D₃ receptor in that: 1) they sediment at 5–6S in sucrose gradients, 2) they are observed in organs other than the intestine, and 3) while they do bind 1α,25-dihydroxyvitamin D₃ at higher concentrations than 25-hydroxyvitamin D₃, they are not observed to transfer either 25-hydroxyvitamin D₃ or 1α,25-dihydroxyvitamin D₃ to the nucleus, $\text{in vitro}$.     

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.     

Adaptation of reovirus to growth in the presence of protease inhibitor E64 segregates with a mutation in the carboxy terminus of viral outer-capsid protein sigma3

Reovirus virions are internalized into cells by receptor-mediated endocytosis. Within the endocytic compartment, the viral outer capsid undergoes acid-dependent proteolysis leading to degradation of sigma3 protein and proteolytic cleavage of micro1/micro1C protein. E64 is a specific inhibitor of cysteine-containing proteases that blocks disassembly of reovirus virions. To identify domains in reovirus proteins that influence susceptibility to E64-mediated inhibition of disassembly, we selected variant viruses by serial passage of strain type 3 Dearing (T3D) in murine L929 cells treated with E64. E64-adapted variant viruses (D-EA viruses) produced 7- to 17-fold-greater yields than T3D did after infection of cells treated with 100 microM E64. Viral genes that segregate with growth of D-EA viruses in the presence of E64 were identified by using reassortant viruses isolated from independent crosses of E64-sensitive strain type 1 Lang and two prototype D-EA viruses. Growth of reassortant viruses in the presence of E64 segregated with the S4 gene, which encodes outer-capsid protein sigma3. Sequence analysis of S4 genes of three D-EA viruses isolated from independent passage series revealed a common tyrosine-to-histidine mutation at amino acid 354 in the deduced amino acid sequence of sigma3. Proteolysis of D-EA virions by endocytic protease cathepsin L occurred with faster kinetics than proteolysis of wild-type T3D virions. Treatment of D-EA virions, but not T3D virions, with cathepsin D resulted in proteolysis of sigma3, a property that also was found to segregate with the D-EA S4 gene. These results indicate that a region in sigma3 protein containing amino acid 354 influences susceptibility of sigma3 to proteolysis during reovirus disassembly.     

Single- and dual-parameter FRET kinase probes based on pleckstrin

Here we describe protocols for preparing and using fluorescent probes that respond to conformational changes by altered Foerster resonance energy transfer (FRET) efficiencies upon phosphorylation or, in principle, other posttranslational modifications (PTMs). The sensor protein, a truncated version of pleckstrin, is sandwiched between short-wavelength-excitation green fluorescent protein (GFP2) and yellow fluorescent protein (EYFP). As a result of complex conformational changes of the protein upon phosphorylation, the introduction of a second PTM consensus sequence bestows sensitivity to a second modification and yields a dual-parameter probe. The first phase of the protocol lays out the cloning strategy for single- and dual-parameter FRET sensors, including the construction of a versatile platform into which different consensus sequences may be inserted to create diverse probes. Protocols for fluorescence microscopy of the probes in living cells and image processing are also described. Probe preparation takes 7 d; microscopy and image processing take 2 h.     

A spatial analytical approach for selecting reintroduction sites for burbot in English rivers

1. Availability of suitable habitat is a prerequisite for species reintroduction success, and to ensure population persistence, investigations of a species’ habitat utilisation throughout its life history should be conducted as part of a feasibility study. 2. Habitat utilisation models for burbot, Lota lota, developed using data from field studies conducted in France and Germany and information from the literature were used to assess the feasibility of reintroducing burbot into rivers of its former native range in eastern England. 3. Per cent tree roots, aquatic vegetation and flow types were important predictors of adult burbot abundance. Furthermore, the habitat utilisation models were supplemented with information from the literature, which suggested that off‐channel habitat such as wetlands and backwaters is important for spawning and nursery stages. 4. An assessment of the habitat availability in the rivers of the burbot’s former native range using variables related to spawning and nursery and adult life stages showed that although adult habitat was widely distributed, the availability of spawning and nursery habitat was less abundant, potentially limiting successful reestablishment. 5. Potential suitable habitat was concentrated in the central and southern areas of the species’ former English distribution. Overall, rivers of the burbot’s former range potentially afford suitable habitat to sustain a reintroduced population. However, sites should be preferentially selected on the basis of having appropriate spawning and nursery areas.