Bacillus arsenicus sp. nov., an arsenic-resistant bacterium isolated from a siderite concretion in West Bengal, India

Strain Con a/3T is a Gram-positive, motile, endospore-forming, rod-shaped and arsenic-resistant bacterium, which was isolated from a concretion of arsenic ore obtained from a bore-hole. The bacterium grew in the presence of 20 mM arsenate and 0·5 mM arsenite. Diaminopimelic acid was present in the cell wall peptidoglycan, MK-7 was the major menaquinone, and iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 1(δ7cis) were the major fatty acids. Based on its phenotypic, chemotaxonomic and phylogenetic characteristics, strain Con a/3T was identified as a member of the genus Bacillus. It exhibited maximum similarity (97 %) at the 16S rRNA gene level with Bacillus barbaricus (DSM 14730T); however, the DNA–DNA relatedness value with B. barbaricus was 60 %. Strain Con a/3T also exhibited a number of phenotypic differences from B. barbaricus (DSM 14730T). Strain Con a/3T was therefore identified as representing a novel species of the genus Bacillus, for which the name Bacillus arsenicus sp. nov. is proposed. The type strain is Con a/3T (=MTCC 4380T=DSM 15822T=JCM 12167T).

Jonesia quinghaiensis sp. nov., a new member of the suborder Micrococcineae

A coryneform strain isolated from soda lake mud in China corresponded in chemotaxonomic characteristics such as peptidoglycan type A4α l-lys–l-ser–d-Glu and major menaquinone MK-9, as well as in its DNA base composition (57 mol% G+C), to its phylogenetic neighbour Jonesia denitrificans. Differences in phenotypic characteristics and the phylogenetic distance (96·6 % 16S rRNA gene sequence similarity) from J. denitrificans justify the proposal of a second species of the genus Jonesia, Jonesia quinghaiensis sp. nov., with the type strain QH3A7T (=DSM 15701T=CGMCC 1.3459T).

Development of sterically stabilized poly(isobutyl 2-cyanoacrylate) nanoparticles by chemical coupling of poly(ethylene glycol)

To develop rapidly biodegradable "stealth" nanoparticles, a physicochemical investigation was done on the formation of PEG-coated poly(isobutyl 2-cyanoacrylate) (PIBCA) nanoparticles. In particular, this study focused on the effect of polymerization conditions on particle size and surface properties, such as charge and hydrophilicity. Among the parameters involved, the pH of the polymerization medium was found to be a key to control the preparation of PEG-coated nanoparticles. Currently, poly(alkylcyanoacrylate) (PACA) nanoparticles are prepared in H2O at pH 2.5, the most appropriate for producing nanoparticles with a mean diameter of 200 nm and an unimodal size distribution. The presence of PEG in the polymerization medium was shown to affect particles formation: only a pH value < 1.5 led to the formation of colloidal nanoparticles, and slight pH variations dramatically affected particle size and PEG association. Polymer chemistry investigations and chemical determination of PEG strongly suggest that PEG associated with nanoparticles was well copolymerized with PIBCA.

A new method to isolate polyalkylcyanoacrylate nanoparticle preparations

A simple method for the separation of polyalkylcyanoacrylate nanoparticles was developed using polyisohexylcyanoacrylate (PIHCA) as a model. Fluorescein isothiocyanate dextran 70 was used to label the nanoparticles. Ultracentrifugation onto a performed sucrose gradient allowed the easy elimination of the dextran and of the free molecules remaining in the upper phase. After such treatment, the physicochemical characteristics of the PIHCA nanoparticles were not modified. This method could be usefully extended to other types of nanoparticles.