ALBERT

Notes: Stimulation of transcription from the Pseudomonas TOL plasmid xylS gene promoter (Ps) and the upperpathway operon promoter (Pu) is dependent on the positive regulator protein XylR activated by an effector molecule such as 3-cholorotoluene, and on RpoN, an RNA polymerase sigma factor. Mutational analysis of the Ps and Pu promoters showed that upstream activator sequences located between -110 and -218bp upstream of the main transcription initiation point are required for regulated expression from these promoters. A search for homologous nucleotide sequences in the -110to -218bp region in Pu and Ps revealed conserved sequences that may act as putative recognition sequences for the XylR protein. Ps and Pu exhibit another well-conserved region at around 50 bp, which is homologous to corresponding sites in other RpoN-dependent promoters and may constitute a binding site for integration host factor (IHF).

Notes: Abstract A new and easy method for the preparation of 1,3,7,9-tetramethylpyrido-[2,3-d∶6,5-d′]-dipyrimidine-2,4,6,8-tetrone is described. The structure of this compound has been solved by means of X-ray diffraction methods. The chemical characterization by spectral (mass, ultraviolet, infrared, and proton nuclear magnetic resonance) and thermal (thermogravimetry and differential scanning calorimetry) method is also reported. The compound is monoclinic, space groupP21/c,a=12.720(5),b=13.688(7),c=8.079(2) Å, β=107.06(4)°,Z=4. The structure consists of discrete tricyclic molecules, stacking playing an important role in crystal packing.

Notes: Summary The response of annular liquid membranes to sinusoidal mass flow rate fluctuations at the nozzle exit is analyzed as a function of the amplitude and frequency of the axial velocity fluctuations at the nozzle exit and thermodynamic compression of the gas enclosed by the membrane. It is shown that both the pressure of the gases enclosed by the annular membrane and the axial distance at which the annular membrane merges on the symmetry axis are periodic functions of time which have the same period as that of the mass flow rate fluctuations at the nozzle exit. They are also nearly sinusoidal functions of time for small amplitudes of the mass flow rate fluctuations at the nozzle exit, and exhibit delay and lag times with respect to the sinusoidal axial velocity fluctuations at the nozzle exit. Both the delay and the lag times are functions of the amplitude and frequency of the mass flow rate fluctuations at the nozzle exit and the polytropic exponent. The amplitudes of both the pressure of the gases enclosed by the annular liquid membrane and the convergence length increase and decrease, resp., as the amplitude and frequency of the mass flow rate fluctuations at the nozzle exit, resp., are increased. They also increase as the polytropic exponent is increased.

Notes: Abstract A domain-adaptive technique which maps a time-dependent, curvilinear geometry into a unit square is used to determine the steady state mass absorption rate and the collapse of annular liquid jets. A method of lines is used to solve the one-dimensional fluid dynamics equations written in weak conservation-law form, and upwind differences are employed to evaluate the axial convective fluxes. The unknown, time-dependent, axial location of the downstream boundary is determined from the solution of an ordinary differential equation which is nonlinearly coupled to the fluid dynamics and gas concentration equations. The equation for the gas concentration in the annular liquid jet is written in strong conservation-law form and solved by means of a method of lines at high Peclet numbers and a line Gauss-Seidel method at low Peclet numbers. The effects of the number of grid points along and across the annular jet, time step, and discretization of the radial convective fluxes on both the steady state mass absorption rate and the jet's collapse rate have been analyzed on staggered and non-staggered grids. The steady state mass absorption rate and the collapse of annular liquid jets are determined as a function of the Froude, Peclet and Weber numbers, annular jet's thickness-to-radius ratio at the nozzle exit, initial pressure difference across the annular jet, nozzle exit angle, temperature of the gas enclosed by the annular jet, pressure of the gas surrounding the jet, solubilities at the inner and outer interfaces of the annular jet, and gas concentration at the nozzle exit. It is shown that the steady state mass absorption rate is proportional to the inverse square root of the Peclet number except for low values of this parameter, and that the possible mathematical incompatibilities in the concentration field at the nozzle exit exert a great influence on the steady state mass absorption rate and on the jet collapse. It is also shown that the steady state mass absorption rate increases as the Weber number, nozzle exit angle, gas concentration at the nozzle exit, and temperature of the gases enclosed by the annular liquid jet are increased, but it decreases as the Froude and Peclet numbers, and annular liquid jet's thickness-to-radius ratio at the nozzle exit are increased. It is also shown that the annular liquid jet's collapse rate increases as the Weber number, nozzle exit angle, temperature of the gases enclosed by the annular liquid jet, and pressure of the gases which surround the jet are increased, but decreases as the Froude and Peclet numbers, and annular liquid jet's thickness-toradius ratio at the nozzle exit are increased. It is also shown that both the ratio of the initial pressure of the gas enclosed by the jet to the pressure of the gas surrounding the jet and the ratio of solubilities at the annular liquid jet's inner and outer interfaces play an important role on both the steady state mass absorption rate and the jet collapse. If the product of these ratios is greater or less than one, both the pressure and the mass of the gas enclosed by the annular liquid jet decrease or increase, respectively, with time. It is also shown that the numerical results obtained with the conservative, domain-adaptive method of lines technique presented in this paper are in excellent agreement with those of a domain-adaptive, iterative, non-conservative, block-bidiagonal, finite difference method which uncouples the solution of the fluid dynamics equations from that of the convergence length.

Notes: Abstract An adaptive, block-bidiagonal finite difference method is used to study the response of annular liquid jets to the injection of mass into the volume enclosed by the annular jet. It is shown that the annular jet's response is characterized by damped oscillations in both the convergence length and the pressure of the gases enclosed by the jet, and that these oscillations are similar to those of an underdamped mass-spring-dashpot system. It is also shown that the maximum amplitude and the number of these oscillations increase as the nozzle exit angle, the initial pressure ratio across the annular jet, the pressure of the gases surrounding the jet, the Weber number, and the rate and duration of the mass injection are increased, are nearly independent of the annular jet's thickness-to-radius ratio at the nozzle exit, and decrease as the Froude number is increased. The numerical calculations presented in this paper indicate that the pressure of the gases enclosed by the annular liquid jet responds instantaneously to the mass injection, whereas there is a lag in the response of the convergence length. This lag is due to the inertia of the jet and assumption that the gases enclosed by the jet are isothermal, and decreases as the injection duration is increased. The calculations also indicate that the critical pressure coefficient of unity determined from the solution of the steady state governing equations can be exceeded without affecting the stability of the annular jet.

Notes: Abstract MoO3/Al2O3 systems have been prepared by calcining at 770 K alumina impregnated with ammonium heptamolybdate (aq), or by calcining molybdena/alumina mixtures at 770 K. Surface polymolybdates have been observed by laser Raman spectroscopy in samples prepared by impregnation: for calcined MoO3/Al2O3 mixtures, X-ray diffraction indicates MoO3 readily spreading over the alumina surface in the presence of water vapour, and this being almost complete after calcination for 2 h.

Notes: Abstract A positive clone against pea (Pisum sativum L.) chloroplast fructose-1,6-bisphosphatase (FBPase; EC 3.1.3.11) antibodies was obtained from a copy DNA (cDNA) library in λgt11. The insert was 1261 nucleotides long, and had an open reading frame of 1143 base pairs with coding capability for the whole FBPase subunit and a fragment of a putative processing peptide. An additional 115 base pairs corresponding to a 3′-untranslated region coding for an mRNA poly(A)+ tail were also found in the clone. The deduced sequence for the FBPase subunit was a 357-amino-acid protein of molecular mass 39253 daltons (Da), showing 82–88% absolute homology with four chloroplastic FBPases sequenced earlier. The 3.1-kilobase (kb)KpnI-SacI fragment of the λgt11 derivative was subcloned between theKpnI-SacI restriction sites of pTZ18R to yield plasmid pAMC100. Lysates ofEscherichia coli (pAMC100) showed FBPase activity; this was purified as a 170-kDa protein which, upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, displayed a 44-kDa band. As occurs with native FBPases, this indicates a homotetrameric structure for the expressed FBPase. When assayed under excess Mg2+ (10 mM), the expressed enzyme had a higher affinity for the substrate than the native pea leaf FBPase; this parameter appears to be substantiated by a tenfold higher specific activity than that of the native enzyme. However, when activated with dithiothreitol plus saturating concentrations of pea thioredoxin (Td) f, both FBPase had similar activities, with a 4:1 Td f-FBPase stoichiometry. In contrast to the native pea chloroplast FBPase, theE. coli-expressed enzyme did not react with the monoclonal antibody GR-PB5. It also had a higher heat sensitivity, with 42% residual activity after heating for 30 min at 60°C, conditions which preserved the native enzyme in a fully active state. These results show the existence of some difference(s) in the conformation of the two FBPases; this could be a consequence of a different expression of the genomic and cDNA clones, or be due to the need for some factor for the correct assembly of the oligomeric structure of the native chloroplast enzyme.

Notes: Summary Three mutants induced in the two-rowed barley variety Beka and their three binary recombinants have been used in an attempt to define an ideotype suitable for Mediterranean agroclimatic conditions. Physiological methods (classical plant growth analysis) together with the study of genotype x environment interaction for grain yield were used to characterize the genotypes. That characterization brought out the huge phenotypical variation produced by only three mutant genes, suggesting that single Mendelian genes may alone explain the quantitative variation, including grain yield, without the necessity of using the polygenic concept. The genotype best adapted to the environments studied is later in heading and has shorter straw and denser spikes than Beka; it also has higher inverse of leaf area rate and grain: leaf area ratio, a lower rate of leaf senescence, and a shorter grain filling period than the original variety.

Notes: Abstract Seven near-isogenic barley lines, differing for three independent mutant genes, were grown in 15 environments in Spain. Genotype x environment interaction (G x E) for grain yield was examined with the Additive Main Effects and Multiplicative interaction (AMMI) model. The results of this statistical analysis of multilocation yield-data were compared with a morpho-physiological characterization of the lines at two sites (Molina-Cano et al. 1990). The first two principal component axes from the AMMI analysis were strongly associated with the morpho-physiological characters. The independent but parallel discrimination among genotypes reflects genetic differences and highlights the power of the AMMI analysis as a tool to investigate G x E. Characters which appear to be positively associated with yield in the germplasm under study could be identified for some environments.