M atrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has been routinely used for the identification of bacteria and fungi from agar culture in many centers in Europe and is increasingly used in North America and elsewhere for primary identification of microorganisms (1, 2, 25). MALDI-TOF instruments use an ionizing laser to vaporize the abundant structural elements (primarily ribosomal proteins) of bacteria and yeasts and analyze the weight and relative abundance of each particle to generate a spectrum. Spectra are compared to a computer database of reference or user-defined organism spectra, and identification is obtained by matching the most similar spectrum in the database to the unknown organism. Performance of the Bruker MALDI BioTyper has been extensively studied in multiple centers and confirms that reliable identification can be obtained for Ͼ95% of the isolates grown on solid media routinely encountered in the clinical laboratory (1,4,5,8,19).More recently, protocols for the direct identification of pathogens from positive blood culture broths have been developed (3,12,16,21,22). Although blood culture broths are usually monobacterial (or monofungal) cultures, the presence of proteins from red cells, white blood cells, and serum interferes with the analysis by adding spectral peaks not found in the organism database. Furthermore, interfering substances such as charcoal (when present) and low organism numbers (as might be encountered with slow-growing or contaminating bacteria) present additional challenges in the use and interpretation of MALDI-TOF spectra for identification pathogens directly from positive blood cultures (24). As a result, many centers have developed in-house methods for preprocessing of blood cultures to optimize recovery of the bacterial proteome. More recently, a commercial kit (Bruker Sepsityper) has been released to simplify the processing steps required for the purification and extraction of the bacterial proteome from positive blood cultures. The system serves to facilitate preprocessing and minimize the impact of the interfering human proteome on the MALDI-TOF analysis. Here we report the performance of the Sepsityper system on the Bruker MALDI BioTyper for the direct identification of pathogens from blood cultures and a cost and turnaround time analysis of the results. MATERIALS AND METHODS Blood cultures.Blood was collected at the bedside and directly inoculated into BacT/Alert SA (aerobic culture) and/or SN (anaerobic) (bioMérieux, Marcy l'Etoile, France). Both bottle types are charcoal free. Bottles were loaded onto the a BacT/Alert instrument (bioMérieux, Marcy l'Etoile, France) and incubated. Bottles were incubated for up to 5 days, and when the operator was notified of a positive blood culture, a Gram stain was performed. All positive bottles were subjected to subculture and routine

All phycobiliproteins contain a conserved, post-translational modification on asparagine 72 of their ␤-subunits. Methylation of this Asn to produce ␥-N-methylasparagine has been shown to increase energy transfer efficiency within the phycobilisome and to prevent photoinhibition. We report here the biochemical characterization of the product of sll0487, which we have named cpcM, from the cyanobacterium Synechocystis sp. PCC 6803. Recombinant apo-phycocyanin and apo-allophycocyanin subunits were used as the substrates for assays with [methyl-3 H]Sadenosylmethionine and recombinant CpcM. CpcM methylated the ␤-subunits of phycobiliproteins (CpcB, ApcB, and ApcF) and did not methylate the corresponding ␣-subunits (CpcA, ApcA, and ApcD), although they are similar in primary and tertiary structure. CpcM preferentially methylated its CpcB substrate after chromophorylation had occurred at Cys 82 . CpcM exhibited lower activity on trimeric phycocyanin after complete chromophorylation and oligomerization had occurred. Based upon these in vitro studies, we conclude that this post-translational modification probably occurs after chromophorylation but before trimer assembly in vivo.

A key challenge to integrating unmanned aerial systems (UASs) into the National Airspace is providing a means for UASs to sense and avoid (SAA) other aircraft. Additionally, successful applications of a SAA system will depend on the degree to which the operator understands the rationale for its maneuvers/decision aids and can interact with the system to tailor and/or override the automation. This paper describes two interface prototypes for the Jointly Optimal Collision Avoidance (JOCA) SAA system that differed in feedback provided on the algorithm's state and planned maneuvers. Results from an operator-in-the-loop simulation are also presented. Although performance was generally similar with both interface types, the participants rated their ability to maintain safe separation from other aircraft and overall situation awareness as better with the interface that provided more visibility into the SAA algorithm's intent.

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