Biotransformation of organic sulfides. Part 9. Formation of (S) para-substituted phenyl methyl sulfoxides by biotransformation usingHelminthosporium species NRRL 4671

Phenyl methyl sulfides substituted in thepara position with methyl, fluoro, chloro, bromo, cyano, nitro, amino, acyl, methoxy, thiomethyl and methylsulfinyl groups have been converted to (S) sulfoxides by biotransformation usingHelminthosporium species NRRL 4671. The highest yields and enantiomeric excesses were obtained with bromo, cyano, methoxy, thiomethyl and methylsulfinyl substituents and in two cases (para-Br and -CN) the products could be crystallized to give (S) sulfoxide of ≥ 96% ee.     

Compartmentation and flux characteristics of nitrate in spruce

The radiotracer¹³N was used to undertake compartmental analyses for NO ₃ ^– in intact non-mycorrhizal roots ofPicea glauca (Moench) Voss. seedlings. Three compartments were defined, with half-lives of exchange of 2.5 s, 20 s, and 7 min. These were identified as representing surface adsorption, apparent free space, and cytoplasm, respectively. Influx, efflux, and net flux as well as cytoplasmic and apparent-free-space nitrate concentrations were estimated for three different concentration regimes of external nitrate. After exposure to external NO ₃ ^– for 3 d, influx was calculated to be 0.09 mol·g^–1·h^–1 (at 10 M [NO ₃ ^– ]_o), 0.5mol·g^–1·h^–1 (at 100 M [NO _inf3 ^sup– ]_o), and 1.2 mol · g^–1· h^–1 (at 1.5 mM [NO ₃ ^– ]_o). Efflux increased with increasing [NO ₃ ^– ]_o, constituting 4% of influx at 10 M, 6% at 100 M, and 21% at 1.5 mM. Cytoplasmic [NO ₃ ^– ] was estimated to be 0.3 mM at 10 uM [NO ₃ ^– ]_o, 2mM at 100 M [NO ₃ ^– ]_o, and 4mM at 1.5 mM [NO ₃ ^– ]_o, while free-space [NO ₃ ^– ] was 16 M, 173 M, and 2.2 mM, respectively. A series of experiments was carried out to confirm the identity of the compartments resolved by efflux analysis. Pretreatment at high temperature or application of 2-chloro-ethanol, sodium dodecyl sulphate or hydrogen peroxide made it possible to distinguish the metabolic (cytoplasmic) phase from the remaining two (physical) phases. Likewise, varying [Pi] of the medium altered efflux and thereby [NO ₃ ^– ]_cyt, but did not affect [NO ₃ ^– ]_{free space}.Abbreviations and Symbols [NO ₃ ^– ]_cyt cytoplasmic NO ₃ ^– concentration - [NO ₃ ^– ]_{free space} apparent-free-space NO ₃ ^– concentration - [NO ₃ ^– ]_o concentration of NO ₃ ^– in the external solution - NO ₃ ^– flux - _co efflux from the cytoplasm - _oc influx to the cytoplasm - _net net flux - _xylem flux to the xylem - _red/vac combined flux to reduction and the vacuole The research was supported by a Natural Sciences and Engineering Research Council, Canada, grant to Dr. A.D.M. Glass and by a University of British Columbia Graduate Fellowship to Herbert J. Kronzucker. Our thanks go to Dr. M. Adam and Mr. P. Culbert at the particle accelerator facility TRIUMF on the University of British Columbia Campus for providing¹³NO ₃ ^– , Drs. R.D. Guy and S. Silim for providing plant material, and Dr. M.Y. Wang, Mr. J. Mehroke and Mr. P. Poon for assistance in experiments and for helpful discussions.     

Developmental regulation of presence of binding sites for neoglycoproteins and endogenous lectins in various embryonic stages of human lung,liver and heart

Protein-carbohydrate interactions are supposed to play key roles in the mechanisms of cell adhesion, biosignalling and intracellular routing, warranting the analysis of the developmental course of expression of epitopes of this system. Thus, a panel of carrier-immobilized carbohydrate ligands was used as probes, namely lactose,N-acetylgalactosamine,N-acetylglucosamine, mannose, fucose and maltose. Additionally, an antibody to an endogenous -galactoside-binding lectin (anti-galectin-1), the biotinylated lectin and two further human lectins, namely the macrophage migration inhibitory factor-binding sarcolectin and serum amyloid P component (SAP) that displays selectivity for sulphated sugars and mannose-6-phosphate, were included. They enabled us to assess the extent of the presence of respective binding sites in fixed sections from human lungs (pulmonary epithelial cells), livers (hepatocytes) and hearts (myocard cells) of 10–50 weeks gestation. Invariably, specific binding was detected in the three organ types, at least in certain stages. In most of the cases, the intensity of staining exhibited developmental regulation. The apparent patterns reveal similarities between the different cell types, as seen with immobilizedN-acetylglucosamine as well as with labelled galectin-1 and sarcolectin. However, drastic differences among such patterns with nearly opposite developmental courses do also occur, as detected for carrier-attached mannose and maltose residues. These results point to a potential importance for the detected glycohistochemical features in human development and substantiate the possibility of differential regulation of the presence of binding sites for distinct sugars within a certain organ and between the individual cell types of the monitored organs.     

Application of solvent extraction to ethanol fermentation

Summary The basic problems of applying solvent extraction to ethanol fermentation were investigated. The selection of solvents was based on the selectivity ratio, which was expressed as the ratio of the ethanol distribution coefficient to the water distribution coefficient. Solvents with high selectivity ratios of more than 50 were found mainly among the alcohols and esters. However, most of these solvents were toxic to ethanol-producing microorganisms. We tried to make a barrier to solvent molecules beneath the surface of gel beads immobilizing the cells as a protection against solvent toxicity. Porapack Q was found to be an effective barrier, and the ethanol production rate of immobilized cells protected with Porapack Q did not change event after the production of eight batches in medium saturated with sec-octanol, which was the most toxic solvent used in our experiments.     

ATP and the processivity of Xenopus laevis DNA polymerase α

We use specific restriction fragments as defined primers for DNA synthesis on single-stranded circular phage fd DNA. These structures are relatively poor templates for a highly purified DNA polymerase α from Xenopus laevis eggs. However, DNA synthesis is stimulated about 5-fold by addition of ATP to the reaction mixture. We show that the deoxynucleotide polymers, synthesized in the presence of ATP, are significantly longer than those produced in the absence of ATP. We also show that this effect is due to a more tenacious binding of DNA polymerase α to DNA and conclude that ATP increases the processivity of the enzyme.     

A followup study of the academic attainment and classroom behavior of children with elevated dentine lead levels

To investigate the impact of low-level lead exposure on children's behavior within a natural setting, we assessed the school performance of a sample of 141 elementary school children classified according to dentine lead level. Twenty-two children had “elevated” levels (≥20 parts per million), 71 had “midrange” levels (10.0–19.9 parts per million), and 48 had “low” levels (<10 parts per million). Four types of outcome data were collected: (1) scores on a standardized group intelligence test, (2) teachers' ratings, (3) incidence of academic failure (assignment to remedial aid, grade retention), and (4) observations of classroom behavior. In general, higher dentine lead levels were associated with less favorable school performance, with most covariance-adjustedp-values in the range of 0.05–0.15. The incidence of grade retention was the outcome most strongly related to lead level. The pattern of results suggests a consistent, though weak relationship between children's dentine lead levels and elementary school performance.     

Vascular morphology of the bovine spermatic cord and testis

Summary The highly coiled testicular artery within the bovine spermatic cord has a constant luminal diameter but a continuously decreasing mural thickness. The pampini form plexus is composed of three interconnected venous networks differing in mesh sizes and calibres. The large veins of the first network display pouches and permanent constrictions, which may serve as throttle devices. The constitutents of the third network are venules or venous capillaries with diameters between 10 and 20 m; they favor a periarterial position or even occupy the media-adventitia border of the testicular artery. All plexus veins are devoid of valves. The existence of true arteriovenous anastomoses between smaller branches of the testicular artery and plexus veins was established by serial sections. The vascular morphology of the spermatic cord is discussed with special attention to a postulated venous-arterial steroid transfer in this region.Supported by the Deutsche Forschungsgemeinschaft and the Stiftung zur Förderung der wissenschaftlichen Forschung an der Universität Bern     

Abdominal segment formation in Spirorbis moerchi (Polychaeta)

Summary The development of abdominal segments in Spirorbis moerchi (Polychaeta: Annelida) was studied by light and electron microscopy. Abdominal segments develop in strict succession from anterior to posterior. Segmentation is initiated in the mesoderm and is followed by segmentation of the ectoderm. The mesoderm of the abdominal segments arises entirely from pygidial residual mesoderm; inward migration of cells from the pygidial ectoderm to give rise to mesoderm does not occur. The primordial germ cells remain distinct from the residual mesoderm of the pygidial growth region. After several abdominal segments have developed, the primordial germ cells migrate posteriorly from the achaetous region, invade the abdominal segments, and give rise to the retroperitoneal gonads. Abdominal segment formation is discussed in terms of heteronomy, primordial germ cell origin, gonad formation, and development of the circulatory system.