13 research outputs found

    Field applications of the second-generation Environmental Sample Processor (ESP) for remote detection of harmful algae: 2006-2007

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    We assess the application of the second-generation Environmental Sample Processor (ESP) for the detection of harmful algal bloom (HAB) species in field and laboratory settings using two molecular probe techniques: a sandwich hybridization assay (SHA) and fluorescent in situ hybridization (FISH). During spring 2006, the first time this new instrument was deployed, the ESP successfully automated application of DNA probe arrays for various HAB species and other planktonic taxa, but non-specific background binding on the SHA probe array support made results interpretation problematic. Following 2006, the DNA array support membrane that we were using was replaced with a different membrane, and the SHA chemistry was adjusted. The sensitivity and dynamic range of these modifications were assessed using 96-well plate and ESP array SHA formats for several HAB species found commonly in Monterey Bay over a range of concentrations; responses were significantly correlated (p < 0.01). Modified arrays were deployed in 2007. Compared to 2006, probe arrays showed improved signal:noise, and remote detection of various HAB species was demonstrated. We confirmed that the ESP and affiliated assays can detect HAB populations at levels below those posing human health concerns, and results can be related to prevailing environmental conditions in near real-time

    Marine microorganisms, biogeochemical cycles, and global climate change

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    Summary:? Marine microbes drive chemical reactions that contribute to Earth's habitability.? Although molecular techniques are used to monitor oceanic microbial communities, collecting intermittent samples for laboratory analysis limits the usefulness of this approach.? Instruments that collect and analyze microbes in situ can provide unprecedented resolution of biogeochemical cycles over large spatial and temporal scales.? We should combine knowledge of key genes with new instruments to obtain time-series information on key marine microbial biogeochemical transformations.The oceans maintain critical ecosystems that, ultimately, determine the habitability of the planet. Moreover, unicellular eukaryotes, bacteria, and archaea are the most abundant organisms within those ecosystems and thus the dominant biomass within the oceans, situated at the base of the food chain that feeds macroscopic invertebrates, fish, and mammals.We are only beginning to uncover the extent of marine microbial genetic diversity and the complex roles that these microbes play in driving the biogeochemistry of global ocean ecosystems. Molecular biology, genomics, microscopy, mass spectrometry, and high-throughput cultivation are already providing useful information on the diversity and activities of marine microflora, including new biochemical pathways. However, in the face of global environmental change, we need to gain a deeper understanding of the distributions of marine microbes and their activities in maintaining ecosystem functions

    Examination of Microbial Proteome Preservation Techniques Applicable to Autonomous Environmental Sample Collection

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    Improvements in temporal and spatial sampling frequency have the potential to open new windows into the understanding of marine microbial dynamics. In recent years, efforts have been made to allow automated samplers to collect microbial biomass for DNA/RNA analyses from moored observatories and autonomous underwater vehicles. Measurements of microbial proteins are also of significant interest given their biogeochemical importance as enzymes that catalyze reactions and transporters that interface with the environment. We examined the influence of five preservatives solutions (SDS-extraction buffer, ethanol, trichloroacetic acid, B-PER, and RNAlater) on the proteome integrity of the marine cyanobacterium Synechococcus WH8102 after four weeks of storage at room temperature. Four approaches were used to assess degradation: total protein recovery, band integrity on an SDS-PAGE gel, and number of protein identifications and relative abundances by 1D LC-MS/MS proteomic analyses. Total protein recoveries from the preserved samples were lower than the frozen control due to processing losses, which could be corrected for with internal standardization. The trichloroacetic acid preserved sample showed significant loss of protein band integrity on the SDS-PAGE gel. The RNAlater preserved sample showed the highest number of protein identifications (103% relative to the control; 520 + 31 identifications in RNAlater versus 504 + 4 in the control), equivalent to the frozen control. Relative abundances of individual proteins in the RNAlater treatment were quite similar to that of the frozen control (average ratio of 1.01 + 0.27 for the 50 most abundant proteins), while the SDS-extraction buffer, ethanol, and B-PER all showed significant decreases in both number of identifications and relative abundances of individual proteins. Based on these findings, RNAlater was an effective proteome preservative, although further study is warranted on additional marine microbes
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