ALBERT

Notes: Abstract Bioassays using rapid-cycling plants allow measurement of multiple endpoints and assessment of impacts on both growth and reproduction. Selections of Brassica rapa develop rapidly in a broad range of soils and are very consistent in production of flower and seed. Their sensitivity to variation in growth conditions was investigated to define the variables that most affect performance. Yield differences between soils were substantial, indicating the need for careful selection and use of control treatments. The sensitivity to contaminants was investigated with applications of mercury (Hg) and zinc (Zn) to three soils. In a sand soil, bloom initiation was slowed by 〈10 mg Hg kg−1 soil and 〈50 mg Zn kg−1 soil. In contrast, lettuce emergence and earthworm survival were less sensitive to these metals in this soil. Survival of Daphnia magna and the Microtox® assay in soil extracts were more sensitive to Hg than bloom initiation, but less sensitive to Zn. A similar relationship among the bioassays was observed for two finer-textured soils, although for these, effects were usually apparent only at soil metal concentrations 〉200 mg kg−1. Enzyme assays were included for comparison, but were not sensitive to Hg contamination. Rapid-cycling B. rapa selections are suitable for routine bioassays, and are representative of several widely distributed and utilized species.

Notes: Abstract Quantitative tectonic modelling demonstrates an interaction of flexure of the lithosphere underlying the western Betics with crustal thinning in the Alboran Basin and flank uplift in the Internal Zone. In the eastern Betics the flexural response is overprinted by post-thrusting extensional events. Lateral variations in thermal structure and rheology of the lithosphere along strike of the Betics shed light on changes in tectonic configuration and are consistent with evidence for lateral variations in the mode of extension in the Alboran Basin. Flexural modelling and subsidence analysis of Neogene basins in the Internal Zone of the Betics, with spatial development controlled by contrasts in lithosphere rheology, demonstrate that at least two extensional events have affected the orogenic evolution of the Betics. The first event appears to reflect Oligocene-Early Miocene rifting observed throughout the Western Mediterranean. The second phase, which caused the present configuration of the Betics, corresponds to Tortonian-Recent extension centered in the Alboran Basin.

Notes: Summary Several formations within the lower part of the Dalradian Appin Group are characterised by calcareous and calc-silicate lithologies. Amphibole occurs in these metasedimentary units in a variety of habits, from fine-grained disseminated crystals, through radiating aggregates permeating the whole rock, to dark green layers consisting of over 90% amphibole. Electron microprobe analyses of these amphiboles exhibit simple compositional trends from tremolite, through tremolitic hornblende to magnesio-hornblende. The only significant substitutions are from tremolite towards alumino-tschermakite [MgSi ⇌ AlviAliv] and from tremolite towards ferri-tschermakite [MgSi ⇌ FeviAliv]. This is in marked contrast to amphiboles from nearby suites of metavolcanic rocks and intrusive metadolerites which exhibit four coupled substitutions, leading from tremolite towards the ferro-actinolite, edenite, alumino-tschermakite and ferritschermakite end-members. These distinctive compositional trends may aid the distinction between para- and ortho-amphibolites elsewhere. Tremolitic amphibole commonly constitutes a high proportion of the calc-silicate rocks, the only other phases present being quartz ± phlogopite. Carbonate minerals are notably absent. This suggests that the sedimentary protolith was high in Mg, such as a dolomitic marl, possibly containing some magnesite. Sedimentological considerations suggest deposition in tropical latitudes in restricted coastal lagoons forming part of an extensive stable shelf bordering a mature landscape.

Notes: Abstract The first intron of the human Proα1(I) collagen gene contains an orientation-dependent enhancer composed of both positive and negative cis-acting elements involved in the transcriptional regulation of this gene. Deletion of a 360 bp Sau 3A intronic fragment spanning nucleotide + 494 to + 854 (S360) resulted in dramatic down-regulation of pCOL-KT (Thompson et al., J Biol Chem 266: 2549–2556, 1991). Using a DNaseI protection assay, we demonstrate a single footprint located at + 590 to + 615 in the S360 fragment; nuclear extracts prepared from mesenchymal and nonmesenchymal cells exhibited similar binding characteristics. A double stranded oligonucleotide representing a consensus Ap-1 binding sequence competed with S360 for binding. In contrast to what occurred in response to S360 deletion which was always accompanied by reduced expression, the deletion of the Ap-1 binding site (+ 598 to + 604) caused either increased or decreased expression of the reporter gene depending on the target cell. Site-directed mutations in the Ap-1-like cis-element of Proα1(I) were also tested in transient expression assays. Consistent with the paradoxical results of Ap-1 deletion, we observed that the functional consequences of mutations in the Ap-1 site also varied in different cells. In A204 cells, one point mutation, which resulted in the loss of protein binding to S360, led to increased CAT activity while another point mutant, which retained binding of the Ap-1 like trans-acting factor(s), showed decreased CAT expression. The effects of these two mutations in the HFL-1 cells were exactly opposite of what was seen for A204 cells. Based on these observations, we postulate that the Ap-1 site plays a critical role in the transcriptional activity of the human Proα1(I) gene. The implications of an apparently dual mode of regulation through a single cis-regulatory element are discussed. (Mol Cell Biochem 118: 119–129, 1992)

Notes: Abstract A bioassay was used to evaluate the effects of cuticular leaf components, isolated fromN. tabacum, N. glutinosa (accessions 24 and 24a), and 23other Nicotiana species, on germinationof P. tabacina (blue mold). The leaf surface compounds includedα- andβ-4,8,13,-duvatriene-l,3-diols (DVT-diols), (13-E)-labda-13-ene-8α-,15-diol (labdenediol), (12-Z)-labda-12,14-diene-8α-ol (cis-abienol), (13-R)-labda-8,14-diene-13-ol (manool), 2-hydroxymanool, a mixture of (13-R)-labda-14-ene-8α,13-diol (sclareol), and (13-S)-labda-14-ene-8α,13-diol (episclareol), and various glucose and/or sucrose ester isolates. The above in acetone were applied onto leaf disks of the blue moldsusceptibleN. tabacum cv. TI 1406, which was then inoculated with blue mold sporangia. Estimated IC50 values (inhibitory concentration) were 3.0μg/cm2 forα-DVT-diol, 2.9μ/cm2 forβ-DVT-diol, 0.4μg/cm2 for labdenediol and 4.7μg/cm2 for the sclareol mixture. Manool, 2-hydroxymanool, andcis-abienol at application rates up to 30μg/cm2 had little or no effect on sporangium germination. Glucose and/or sucrose ester isolates from the cuticular leaf extracts of 23Nicotiana species and three different fractions fromN. bigelovii were also evaluated for antimicrobial activity at a concentration of 30μg/cm2. Germination was inhibited by 〉20% when exposed to sugar esters isolated fromN. acuminata, N. benthamiana, N. attenuata, N. clevelandii, andN. miersii, and accessions 10 and 12 ofN. bigelovii. These results imply that a number of compounds may influence resistance to blue mold in tobacco.

Notes: Summary Single fibres of different sarcomere length at rest have been isolated from the claw muscle of the yabby (Cherax destructor), a decapod crustacean. Fibres of either long (SL 〉 6 μm) or short (SL 〈 4 μm) sarcomere length have been mechanically skinned and were maximally activated by Ca2+ and Sr2+ under various experimental conditions (ionic strength, in the presence of 2,3 butanedione monoxime (BDM)) to determine differences in their contractile properties. Isometric force was measured simultaneously with either myofibrillar MgATPase or fibre stiffness in both fibre types. The ultrastructure of individual long- and short-sarcomere fibres was also determined by electron microscopy. The long-sarcomere fibres developed greater tension (30.48±1.72 N cm−2) when maximally activated by Ca2+ compared with the short-sarcomere fibres (18.60±0.80 N cm−2). The difference in the maximum Ca2+-activated force can be explained by the difference in the amount of filament overlap between the two fibre types. The maximum Ca2+-activated myofibrillar MgATPase rate in the short-sarcomere fibres (1.60±0.27 mmol ATP l−1 s−1) was higher, but not significantly different from the ATPase rate in fibres with long-sarcomeres (1.09±0.14 mmol ATP l−1 s−1). As the concentration of myosin is estimated to be higher only by a factor of 1.22 in the short-sarcomere preparations there is no evidence to suggest that the myofibrillar MgATPase activity is different in the long- and short-sarcomere preparations. The maximum Ca2+-activated force (P 0) of both short- and long-sarcomere fibres was quite insensitive to BDM compared with vertebrate muscle. Force decreased to 60.2±5.3% and 76.1±2.7% in the short- and long-sarcomere fibres respectively in the presence of 100 mmol l−1 BDM. The difference in the force depression between the. long- and short-sarcomere fibres is statistically significant (p〈0.05). Fibre stiffness during maximum Ca2+-activation expressed as percentage maximum force per nm per half sarcomere was higher by a factor of 3.5 in short-sarcomere fibres than in long-sarcomere fibres suggesting that the compliance of the filaments in the long-sarcomere fibres is considerably higher than in the short-sarcomere fibres. Sr2+ could not activate the contractile apparatus to the same level as that seen by Ca2+ in either fibre type: the maximum Sr2+-activated force was (20±3%) and (63±3%) of the maximum Ca2+-activated force response in short- and long-sarcomere fibres, respectively. The ratio between fibre stiffness in the maximum Sr2+-activating solution and the Ca2+-activating solution was very similar to the ratio between the maximum Sr2+-activated force and Ca2+-activated force in either type of fibres, suggesting that the number of attached crossbridges is lower in the fibres when maximally activated by Sr2+ than when maximally activated by Ca2+. The short-sarcomere fibres were also more sensitive to changes in ionic strength than long-sarcomere fibres. In conclusion these results indicate that while several important specific characteristics of the short- and long-sarcomere length fibres (ATPase, maximum Ca2+-activated force and fibre stiffness) can be explained solely on differences in the ultrastructure (length and density per cross-sectional area of myosin filaments) there are also differences in the properties of the proteins involved in the force production and regulation evidenced by the differential effect of Sr2+, BDM and ionic strength on contractile activation in the two fibre types.

Notes: Abstract This study was conducted to corroborate findings that females invoke a decision rule that is significantly different from that of their male counterparts when making ethical value judgements. In addition, the study examines whether the same decision rule is used by men and women for all types of ethical situations. The results show that males and females use different decision rules when making ethical evaluations, although there are types of situations where there are no significant differences in decision rules used by men and women. The results do not suggest that any one particular decision rule is used by the majority of either males or females in different types of ethical judgements. There is a greater diversity in decision rules used by females than by males.

Notes: Abstract Time-resolved X-ray scattering has been used to study the kinetics of crystallization of amorphous metals on time scales varying from minutes to milliseconds. Measurements have been at the National Synchrotron Light Source, using a wide-bandpass monochomator and fast linear position-sensitive detector system at the IBM/MIT beamline X-20C. With this apparatus, scattering patterns from the transforming material can be acquired with 3-ms time resolution. A fast pyrometric temperature controller has been developed to change and regulate the sample temperature with microsecond response. In a typical measurement, two synchronized position-sensitive detectors provide complementaryin situ information about the transformation. The first is used for wide-angle scattering and allows us to determine which phases are present and to what extent. Changes in lattice parameter and particle size can also be deduced. The second detector measures small-angle scattering, yielding additional information about the microstructure, such as the spacing between lammellae in eutectic systems. At relatively slow transformation rates, quantitative measurements of crystal volume fractions as small as 10−4 are possible. In many systems, as the transformation rate is increased, the crystallization mechanism changes such that new metastable crystal phases are formed en route to the equilibrium structure.

Notes: Abstract We studied the dynamics of Cd uptake and depuration in epilithic periphyton and in the grazing amphipod Hyalella azteca. Both stable Cd, sufficient to achieve an aqueous concentration of 90 ng L−1, and its radiotracer 109Cd, were added during 1987 to the epilimnion of oligotrophic Lake 382 of the Experimental Lakes Area in northwestern Ontario. Cadmium dynamics within both periphyton and Hyalella were rapid, with equilibrium being approached within two weeks. For periphyton, the Cd uptake rate constant (K uw ) was 3.8×104 d−1 with a depuration rate of 0.29 d−1. For Hyalella the depuration rate was 0.36 d−1, 10% due to growth dilution and 90% to excretion or desorption. The total Cd uptake rate (k ut ) by Hyalella was 6.1×104 d−1, with more of the uptake (58%) derived from food (periphyton) than from water. Hyalella assimilated 80% of ingested Cd. Steady-state bioconcentration factors (BCF) were at least 10-fold higher than previously published values for Amphipoda. In periphyton and Hyalella the BCF were 1.2×105 and 3.2×105, respectively.

Notes: Abstract Protein A fromStaphylococcus aureus is a powerful diagnostic reagent and has several uses in human disease therapy. Expression in non-pathogenicEscherichia coli containing recombinant plasmids coding for this protein has increased its availability, but can reduce the stability of the plasmid-bearing host. By employing immune electron microscopy, we have determined thatE. coli containing stable plasmids coding for a truncated version of protein A, without the membrane binding site, secrete this protein through the cytoplasmic membrane and into the periplasmic space, where it accumulates.E. coli containing unstable plasmids, however, which code for the complete protein including the membrane-binding site, target the protein into the cytoplasmic membrane. This accumulation of protein A in theE. coli cytoplasmic membrane inhibits the formation of septa between dividing cells and results in aberrant elongated, multi-chromosomal forms.