Indistinguishable photons from separated silicon-vacancy centers in diamond.

We demonstrate that silicon-vacancy (SiV) centers in diamond can be used to efficiently generate coherent optical photons with excellent spectral properties. We show that these features are due to the inversion symmetry associated with SiV centers. The generation of indistinguishable single photons from separated emitters at 5 K is demonstrated in a Hong-Ou-Mandel interference experiment. Prospects for realizing efficient quantum network nodes using SiV centers are discussed.

Multiple intrinsically identical single-photon emitters in the solid state.

Emitters of indistinguishable single photons are crucial for the growing field of quantum technologies. To realize scalability and increase the complexity of quantum optics technologies, multiple independent yet identical single-photon emitters are required. However, typical solid-state single-photon sources are inherently dissimilar, necessitating the use of electrical feedback or optical cavities to improve spectral overlap between distinct emitters. Here we demonstrate bright silicon vacancy (SiV(-)) centres in low-strain bulk diamond, which show spectral overlap of up to 91% and nearly transform-limited excitation linewidths. This is the first time that distinct single-photon emitters in the solid state have shown intrinsically identical spectral properties. Our results have impact on the application of single-photon sources for quantum optics and cryptography.

Purification and Properties of a Thermostable Pullulanase from a Newly Isolated Thermophilic Anaerobic Bacterium, Fervidobacterium pennavorans Ven5.

Extremely thermophilic anaerobic fermentative bacteria growing at temperatures between 50 and 80(deg)C (optimum, 65 to 70(deg)C) were isolated from mud samples collected at Abano Terme spa (Italy). The cells were gram-negative motile rods, about 1.8 (mu)m in length and 0.6 (mu)m in width, occurring singly and in pairs. Cells commonly formed spheroids at one end similar to Fervidobacterium islandicum and Fervidobacterium nodosum. The new isolate differs from F. nodosum by the 7% higher G+C content of its DNA (40.6 mol%) but is similar to Fervidobacterium pennavorans and F. islandicum in its G+C content and phenotypic properties. The phylogenetic dendrogram indicates that strain Ven5 belongs to the order Thermotogales and shows the highest 16S ribosomal DNA sequence similarity to F. pennavorans, F. islandicum, and F. nodosum, with similarities of 99.0, 98.6, and 96.0%, respectively. During growth on starch the strain produced a thermostable pullulanase of type I which preferentially hydrolyzed (alpha)-1,6 glucosidic linkages. The enzyme was purified 65-fold by anion-exchange, gel permeation, and hydrophobic chromatography. The native pullulanase has a molecular mass of 240,000 Da and is composed of three subunits, each with a molecular mass of 77,600 Da as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Optimal conditions for the activity and stability of the purified pullulanase were pH 6.0 and 85(deg)C. At pH 6.0, the half-life of the enzyme was over 2 h at 80(deg)C and 5 min at 90(deg)C. This is the first report on the presence of pullulanase type I in an anaerobic bacterium.

Lentzea gen. nov., a new genus of the order Actinomycetales.

We describe a new genus of mesophilic actinomycetes, for which we propose the name Lentzea. The strains of this genus form abundant aerial hyphae that fragment into rod-shaped elements. Whole-cell hydrolysates contain the meso isomer of diaminopimelic acid and no characteristic sugar (wall chemotype III). The phospholipid pattern type is type PII (phosphatidylethanolamine is the characteristic phospholipid); the major menaquinone is MK-9. The fatty acid profile comprises saturated, unsaturated, and branched-chain fatty acids of the iso and anteiso types in addition to tuberculostearic acid (10Me-C18:0). A 16S ribosomal DNA sequence analysis revealed that the genus Lentzea is phylogenically related to the genera Actinosynnema, Saccharothrix, and Kutzneria. The type species of this genus is Lentzea albidocapillata sp. nov.; the type strain of this species is strain IMMIB D-958 (= DSM 44073).

A new tremelloid yeast isolated from Asterophora lycoperdoides (Bull.: Fr.) Ditm.

Reports of a yeast stage of the homobasidiomycete Asterophora lycoperdoides were reexamined. Substantial differences in the physiological description and a gap of 11% G + C content were detected between the yeast and the mycelium. On the basis of nDNA reassociation experiments and restriction enzyme cleavage patterns of mtDNA using two different enzymes it has been concluded that the yeast strains and the mycelia are probably not the same species. The results of earlier reports about the life cycle, however, cannot be explained with these data. This yeast is newly described, because it shows unique physiological properties and no significant homology in DNA-DNA reassociation experiments to species it would normally be identified with in the literature. Because of its dolipore with cup-shaped parenthesome, we prefer the term tremelloid over assigning the strains to any existing genus, because no sexual structure or ballistospore has been observed so far.