Chloroplast DNA diversity in eggplant (Solanum melongena) and its related species S. incanum and S. marginatum

Summary The potential of isozymes for distinguishing asparagus varieties was carried out by a survey on 21 varieties using 10 enzyme systems: GOT, SkDH, DIA, PGM, MDH, IDH, PGD, ACP, PGI, MR and ADH. Only 3 enzymes, SkDH, GOT and PGM, showed useful polymorphisms. The varieties were found heterogeneous according to their genetic structure: open pollinated varieties were more heterogeneous than clonal hybrids; the F1 hybrid and the vitroclones were homogeneous. As expected from the narrow genetic basis of the varieties, only a few alleles per isozyme locus were present. Moreover, for each enzyme, one allele or type was predominant so that the discriminating power of the method was low. However some of the varieties could be identified and different applications of the results are presented.Abbreviations D.U.S.- Distinction-Uniformity-Stability - ACO- aconitase - ACP- acid phosphatase - ADH- alcohol dehydrogenase - CAT- catalase - DIA- diaphorase - END- endopeptidase - GOT- glutamate oxaloacetate transaminase - IDH- isocitrate dehydrogenase - MDH- malate dehydrogenase - MR- menadione reductase - PGI- phosphoglucoisomerase - PGM- phosphoglucomutase - PGD- phosphoglucose dehydrogenase - POX- peroxidase - SkDH- shikimate dehydrogenase     

N-acyl-homoserine lactones from Enterobacter sakazakii (Cronobacter spp.) and their degradation by Bacillus cereus enzymes

A chemical study of acyl-homoserine lactones (acyl-HSLs) produced by Enterobacter sakazakii resulted in the identification of three molecules: (S)-N-heptanoyl-HSL, (S)-N-dodecanoyl-HSL and (S)-N-tetradecanoyl-HSL. Mixed cultures of E. sakazakii and Bacillus cereus depleted E. sakazakii acyl-HSLs, suggesting acyl-HSL degradation by B. cereus hydrolases (hydrolysis of the lactone or amide moiety). The expression of B. cereus acyl-HSL lactonase and acyl-homoserine acylase was confirmed by monitoring the biotransformation of (S)-N-dodecanoyl-HSL into (S)-N-dodecanoyl-homoserine, dodecanoic acid and homoserine in the presence of B. cereus whole cells, using electrospray-mass spectrometry (ESI-MS).     

Dynamical superconducting order parameter domains in Sr2RuO4

We present direct evidence for complex p-wave order parameter symmetry and the presence of dynamical chiral order parameter domains of the form px +/- ipy in the ruthenate superconductor Sr2RuO4. The domain structure creates differences in the magnetic field modulation of the critical current of Josephson junctions fabricated on orthogonal faces of Sr2RuO4 single crystals. Transitions between the chiral states of a domain or the motion of domain walls separating them generates telegraph noise in the critical current as a function of magnetic field or time and is responsible for hysteresis observed in field sweeps of the critical current. The presence of such domains confirms the p-wave triplet spin and complex (broken time-reversal symmetry) nature of the superconducting pairing state in Sr2RuO4.     

Migration of biological control agent Rhizobium vitis strain ARK-1 in grapevine stems and inhibition of galls caused by tumorigenic strain of R. vitis

Journal of General Plant Pathology - Nonpathogenic strain ARK-1 of Rhizobium vitis has antagonistic activity against a tumorigenic (Ti) strain of R. vitis and works as a biocontrol agent, but the...     

Chloroplast DNA analysis of eggplant (Solanum melongena) and related species for their taxonomic affinity

Summary Total chloroplast DNA (cpDNA) from Solanum incanum, a wild relative of eggplant, was used to probe total DNA of Solanum melongena (eggplant). The DNA fragments detected were the same as observed using purified chloroplast DNA. Chloroplast DNAs were also analysed for nine species of Solanum that are cross-compatible with eggplant: S. aethiopicum, S. anguivi, S. gilo, S. incanum, S. indicum, S. integrifolium, S. macrocarpon, S. olivare and S. panduriforme.Restriction fragments generated by eight enzymes were recorded as present or absent, and a matrix for all fragment positions, species and enzymes was used for cluster analysis. In the resulting dendrogram, the species tested formed three distinct groups: (1) S. aethiopicum, S. anguivi, S. gilo, S. indicum, S. integrifolium and S. olivare, (2) S. incanum, S. melongena and S. panduriforme, (3) S. macrocarpon. Six species of the first group belonging to section Oliganthes appears more closely related to the second group members belonging to section Melongena than does S. macrocarpon, which also belongs to section Melongena. Within the second group, S. panduriforme is slightly more like eggplant than is S. incanum.     

Spin disorder on a triangular lattice

As liquids crystallize into solids on cooling, spins in magnets generally form periodic order. However, three decades ago, it was theoretically proposed that spins on a triangular lattice form a liquidlike disordered state at low temperatures. Whether or not a spin liquid is stabilized by geometrical frustration has remained an active point of inquiry ever since. Our thermodynamic and neutron measurements on NiGa2S4, a rare example of a two-dimensional triangular lattice antiferromagnet, demonstrate that geometrical frustration stabilizes a low-temperature spin-disordered state with coherence beyond the two-spin correlation length. Spin liquid formation may be an origin of such behavior.