An aerobic methanotrophic bacterium was isolated from a collapsed palsa soil in northern Norway and designated strain NE2 T . Cells of this strain were Gram-stain-negative, non-motile, non-pigmented, slightly curved thick rods that multiplied by normal cell division. The cells possessed a particulate methane monooxygenase enzyme (pMMO) and utilized methane and methanol. Strain NE2 T grew in a wide pH range of 4.1-8.0 (optimum pH 5.2-6.5) at temperatures between 6 and 32 8C (optimum 18-25 8C), and was capable of atmospheric nitrogen fixation under reduced oxygen tension. The major cellular fatty acids were C 18 : 1 v7c, C 16 : 0 and C 16 : 1 v7c, and the DNA G+C content was 61.7 mol%. The isolate belonged to the family Beijerinckiaceae of the class Alphaproteobacteria and was most closely related to the facultative methanotroph Methylocapsa aurea KYG T (98.3 % 16S rRNA gene sequence similarity and 84 % PmoA sequence identity). However, strain NE2 T differed from Methylocapsa aurea KYG T by cell morphology, the absence of pigmentation, inability to grow on acetate, broader pH growth range, and higher tolerance to NaCl. Therefore, strain NE2 T represents a novel species of the genus Methylocapsa, for which we propose the name Methylocapsa palsarum sp. nov. The type strain is NE2 T (5LMG 28715 T 5VKM B-2945 T ).

Frenulate species were identified from a high Arctic methane seep area on Vestnesa Ridge, western Svalbard margin (79°N, Fram Strait) based on mitochondrial cytochrome oxidase subunit I (mtCOI). Two species were found: Oligobrachia haakonmosbiensis, and a new, distinct, and undescribed Oligobrachia species. The new species adds to the cryptic Oligobrachia species complex found at high latitude methane seeps in the north Atlantic and the Arctic. However, this species displays a curled tube morphology and light brown coloration that could serve to distinguish it from other members of the complex. A number of single tentacle individuals were recovered which were initially thought to be members of the only unitentaculate genus, Siboglinum. However, sequencing revealed them to be the new species and the single tentacle morphology, in addition to thin, colorless, and ringless tubes indicate that they are juveniles. This is the first known report of juveniles of northern Oligobrachia. Since the juveniles all appeared to be at about the same developmental stage, it is possible that reproduction is either synchronized within the species, or that despite continuous reproduction, settlement, and growth in the sediment only takes place at specific periods. The new find of the well‐known species O. haakonmosbiensis extends its range from the Norwegian Sea to high latitudes of the Arctic in the Fram Strait. We suggest bottom currents serve as the main distribution mechanism for high latitude Oligobrachia species and that water depth constitutes a major dispersal barrier. This explains the lack of overlap between the distributions of northern Oligobrachia species despite exposure to similar current regimes. Our results point toward a single speciation event within the Oligobrachia clade, and we suggest that this occurred in the late Neogene, when topographical changes occurred and exchanges between Arctic and North Atlantic water masses and subsequent thermohaline circulation intensified.

The second largest sink for atmospheric methane (CH4) is atmospheric methane oxidizing-bacteria (atmMOB). How atmMOB are able to sustain life on the low CH4 concentrations in air is unknown. Here, we show that during growth, with air as its only source for energy and carbon, the recently isolated atmospheric methane-oxidizer Methylocapsa gorgona MG08 (USCα) oxidizes three atmospheric energy sources: CH4, carbon monoxide (CO), and hydrogen (H2) to support growth. The cell-specific CH4 oxidation rate of M. gorgona MG08 was estimated at ~0.7 × 10−18 mol cell−1 h−1, which, together with the oxidation of CO and H2, supplies 0.38 kJ Cmol−1 h−1 during growth in air. This is seven times lower than previously assumed necessary to support bacterial maintenance. We conclude that atmospheric methane-oxidation is supported by a metabolic flexibility that enables the simultaneous harvest of CH4, H2 and CO from air, but the key characteristic of atmospheric CH4 oxidizing bacteria might be very low energy requirements.

The antimicrobial drug chloramphenicol (CAM) exhibits activity against resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). However, its use has been limited due to its toxicity. As the threat of antibiotic resistance continues to grow, a promising approach might be to increase the use of historical antimicrobial agents that demonstrate clinical efficacy, but are hampered by toxicity. We therefore aimed to prepare a liposome-in-hydrogel system for dermal delivery of CAM. Chitosan (CS) was used as the hydrogel vehicle due to its antimicrobial activity and excellent biocompatibility. All critical preparation steps were carried out by dual centrifugation (DC). The DC-method proved to be fast and simple, and organic solvents were avoided in all processing steps. Liposomes with high drug entrapment (49-56%), low polydispersity and a size of approximately 120nm were produced. Mixing of liposomes into CS-hydrogel by DC produced a homogenous liposomes-in-hydrogel system. Bioadhesive properties were good and comparable to plain CS-hydrogel formulations. Ex vivo permeation studies using pig skin indicated a sustained release of CAM and limited skin permeation. The in vitro antimicrobial activity of CAM in the new liposome-in-hydrogel formulation was similar or better as compared to CAM in solution. Thus, the new formulation was considered highly promising.

Methylocapsa palsarum NE2T is an aerobic, mildly acidophilic, obligate methanotroph. Similar to other Methylocapsa species, it possesses only a particulate methane monooxygenase and is capable of atmospheric nitrogen fixation. The genome sequence of this typical inhabitant of subarctic wetlands and soils also contains genes indicative of aerobic anoxygenic photosynthesis.