Phosphate-limited ocean regions select for bacterial populations enriched in the carbon-phosphorus lyase pathway for phosphonate degradation.

In tropical and subtropical oceanic surface waters phosphate scarcity can limit microbial productivity. However, these environments also have bioavailable forms of phosphorus incorporated into dissolved organic matter (DOM) that microbes with the necessary transport and hydrolysis metabolic pathways can access to supplement their phosphorus requirements. In this study we evaluated how the environment shapes the abundance and taxonomic distribution of the bacterial carbon-phosphorus (C-P) lyase pathway, an enzyme complex evolved to extract phosphate from phosphonates. Phosphonates are organophosphorus compounds characterized by a highly stable C-P bond and are enriched in marine DOM. Similar to other known bacterial adaptions to low phosphate environments, C-P lyase was found to become more prevalent as phosphate concentrations decreased. C-P lyase was particularly enriched in the Mediterranean Sea and North Atlantic Ocean, two regions that feature sustained periods of phosphate depletion. In these regions, C-P lyase was prevalent in several lineages of Alphaproteobacteria (Pelagibacter, SAR116, Roseobacter and Rhodospirillales), Gammaproteobacteria, and Actinobacteria. The global scope of this analysis supports previous studies that infer phosphonate catabolism via C-P lyase is an important adaptive strategy implemented by bacteria to alleviate phosphate limitation and expands the known geographic extent and taxonomic affiliation of this metabolic pathway in the ocean.

Observation of Tunneling-Assisted Highly Forbidden Single-Photon Transitions in a Ni_{4} Single-Molecule Magnet.

Forbidden transitions between energy levels typically involve violation of selection rules imposed by symmetry and/or conservation laws. A nanomagnet tunneling between up and down states violates angular momentum conservation because of broken rotational symmetry. Here we report observations of highly forbidden transitions between spin states in a Ni_{4} single-molecule magnet in which a single photon can induce the spin to change by several times ℏ, nearly reversing the direction of the spin. These observations are understood as tunneling-assisted transitions that lift the standard Δm=±1 selection rule for single-photon transitions. These transitions are observed at low applied fields, where tunneling is dominated by the molecule's intrinsic anisotropy and the field acts as a perturbation. Such transitions can be exploited to create macroscopic superposition states that are not typically accessible through single-photon Δm=±1 transitions.

Study of the Association between Human T-cell Lymphotropic Virus Type 1 Infection and Lichen Planus.

OBJECTIVE(S): Lichen Planus is a common disease with unknown etiology which affects the skin and mucosa. Recent studies have focused on the possible role of the virus in the pathogenesis of Lichen Planus. The purpose of this study was to determine the association between the human T-cell lymphotropic virus type 1 and Lichen Planus. MATERIALS AND METHODS: This case control study was conducted on a total of 200 patients. The case group consisted of 100 patients with a confirmed histopathological diagnosis of lichen planus disease, and the control group consisted of 100 healthy blood donors without any signs or symptoms of skin diseases, and who were similar in age and sex to the case group. Blood samples of both participants in the case and control groups were examined for the presence of anti -HTLV-I antibodies using the ELISA method. The polymerase chain reaction for human T-cell lymphotropic virus type 1 was conducted in cases in which the findings for antihuman T-cell lymphotropic virus type 1 antibody test was positive, and statistical analysis was conducted on the obtain results. RESULTS: One case in the case group was infected with human T-cell lymphotropic virus type 1; however, no infection was observed in the control group. The difference was not statistically significant (P = 1). CONCLUSION: Based on the obtained results, no association was observed between the human T-cell lymphotropic virus type 1 infection and Lichen Planus.