Nursery multivariate statistical analysis.

<p>Principal component analysis (PCA) scores plot of nursery phase shrimp. (A) Each point represents the mean PC score for the sampling time point (ND: nursery phase day) and the error bars represent the standard error of the mean. The solid black arrow suggests metabolic changes in relationship to growth, while the dashed red arrow denotes a deviation from and a return to “normal” growth. (B) PCA scores plot of all nursery phase shrimp grouped by pre-event, event (TAN spike), and post event. (C) ¹H significant difference spectra (SDS) displaying metabolite changes in response to the TAN spike and growth. The top SDS spectrum compares pre-TAN spike vs. TAN spike, the middle spectrum compares TAN spike vs. post-TAN spike and the bottom spectrum compares pre-TAN spike vs. post-TAN spike. Metabolites increasing as a result of the TAN spike are positive in the top two spectra and metabolites increasing during growth are positive in the bottom spectrum. Not all compounds mentioned in the text are annotated here.</p

Evaluation of Pacific White Shrimp (<i>Litopenaeus vannamei</i>) Health during a Superintensive Aquaculture Growout Using NMR-Based Metabolomics

<div><p>Success of the shrimp aquaculture industry requires technological advances that increase production and environmental sustainability. Indoor, superintensive, aquaculture systems are being developed that permit year-round production of farmed shrimp at high densities. These systems are intended to overcome problems of disease susceptibility and of water quality issues from waste products, by operating as essentially closed systems that promote beneficial microbial communities (biofloc). The resulting biofloc can assimilate and detoxify wastes, may provide nutrition for the farmed organisms resulting in improved growth, and may aid in reducing disease initiated from external sources. Nuclear magnetic resonance (NMR)-based metabolomic techniques were used to assess shrimp health during a full growout cycle from the nursery phase through harvest in a minimal-exchange, superintensive, biofloc system. Aberrant shrimp metabolomes were detected from a spike in total ammonia nitrogen in the nursery, from a reduced feeding period that was a consequence of surface scum build-up in the raceway, and from the stocking transition from the nursery to the growout raceway. The biochemical changes in the shrimp that were induced by the stressors were essential for survival and included nitrogen detoxification and energy conservation mechanisms. Inosine and trehalose may be general biomarkers of stress in <i>Litopenaeus vannamei</i>. This study demonstrates one aspect of the practicality of using NMR-based metabolomics to enhance the aquaculture industry by providing physiological insight into common environmental stresses that may limit growth or better explain reduced survival and production.</p> </div

Raceway multivariate statistical analysis.

<p>PCA scores plot of muscle tissue from growout phase shrimp from the raceway system. (A) Each point represents the mean PC score for the sampling time point (ND: nursery phase day, GD: growout phase day) and the error bars represent the standard error of the mean. The solid black arrow suggests metabolic changes in relationship to growth, while the dashed red arrow denotes a deviation from and a return to “normal” growth. (B) Scores plot of individual growout phase shrimp colored by pre-fast (blue), fast (red), and post-fast (green). (C) SDS displaying metabolite changes in response to the fasting period and growth. The top spectrum compares pre-fast vs. fast shrimp, the middle spectrum represents fasted shrimp vs. post-fast shrimp, and the bottom spectrum displays metabolite changes from pre-fast vs. post-fast shrimp. Metabolites increasing as a result of the fast are positive in the top two spectra and metabolites increasing during growth are positive in the bottom spectrum. Not all significantly changing metabolites mentioned in the text are annotated here.</p

Affected biochemical pathways.

<p>Schematic depiction of the biochemical pathways <i>L. vannamei</i> may use to avoid NH₃ toxicity during the TAN spike in the nursery phase. Blue arrows indicate normal metabolism pathways, red symbols indicate interrupted pathways or increasing concentrations due to the TAN spike, gray arrows denote pathways of microbial origin. (1) Increase in protein catabolism; (2) Inhibition of RNA and DNA synthesis; (3) Urea excretion through the OUC; (4) Uric acid excretion by purine catabolism; (5) Urea excretions by (a) pyrimidine oxidation and/or (b) pyrimidine reduction.</p

Stress of stocking.

<p>(A) Raceway stocking stress PCA scores plot of muscle tissue. Sampling from one day pre-stock (ND 63) and one day Post-stock (GD -7). Ellipses represent 95% confidence intervals. (B) SDS of metabolites changing in response to the stress of stocking from the nursery to the raceway. Metabolites increasing as a result of the stocking are positive and metabolites decreasing are negative.</p

Untargeted Metabolomics Analyses and Contaminant Chemistry of Dreissenid Mussels at the Maumee River Area of Concern in the Great Lakes

Bivalves serve as an ideal ecological indicator; hence, their use by the NOAA Mussel Watch Program to monitor environmental health. This study aimed to expand the baseline knowledge of using metabolic end points in environmental monitoring by investigating the dreissenid mussel metabolome in the field. Dreissenids were caged at four locations along the Maumee River for 30 days. The mussel metabolome was measured using nuclear magnetic resonance spectroscopy, and mussel tissue chemical contaminants were analyzed using gas or liquid chromatography coupled with mass spectrometry. All Maumee River sites had a distinct mussel metabolome compared to the reference site and revealed changes in the energy metabolism and amino acids. Data also highlighted the importance of considering seasonality or handling effects on the metabolome at the time of sampling. The furthest upstream site presented a specific mussel tissue chemical signature of pesticides (atrazine and metolachlor), while a downstream site, located at Toledo’s wastewater treatment plant, was characterized by polycyclic aromatic hydrocarbons and other organic contaminants. Further research into the dreissenid mussel’s natural metabolic cycle and metabolic response to specific anthropogenic stressors is necessary before successful implementation of metabolomics in a biomonitoring program

Molecular modeling suggests one possible conformation that (1→6)-β-linked glucan side chains may exhibit, that is, a hook-like, bent structure.

<p>Structure A (top) is a linear polymer containing ten (1→3)-β-linked repeat units in the polymer chain. The linear (1→3)-β-linked glucan backbone structure assumes an open helical conformation. Structure B (bottom) is the same linear structure except a side chain branches from the third repeat unit. The side chain contains five (1→6)-β-linked repeat units. The curvature and hook-like structure of the side chain is evident in this model where the structure has been rotated slightly to optimize visualization of the curved side chain. The structures are rendered using JMOL <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0027614#pone.0027614-anonymous1" target="_blank">[39]</a>.</p

Comparison of average side chain lengths, SCn, and branching frequencies, Br Freq, for several strains of <i>C. glabrata</i> isolated by 2 different methods.

<p>Comparison of average side chain lengths, SCn, and branching frequencies, Br Freq, for several strains of <i>C. glabrata</i> isolated by 2 different methods.</p

2D NMR spectra of the glycosidic linkages and non-reducing termini of the (1→3,1→6)-β-D-glucan isolated from <i>C. glabrata ace2</i> strain.

<p>(a) The three different (1→6)-β-linked glycosidic bonds from the side chain are detailed in the NOESY 2D NMR spectrum for SC1, SC Internal, and SC NRT glucosyl groups associated with H1 SC1, SC H1 and SC NRT H1. A: H6Br,H6′Br/H1SC1; B: H6SCn,H6′SCn/H1SC(n+1); C: H6SC(n-1),H6′SC(n-1)/H1SCNRT. (b) Similarity of the structures of the glycosyl group associated with SC NRT H1 and NRT H1 is indicated in the TOCSY 2D NMR spectrum.</p

Assignment of ¹³C and ¹H chemical shifts for the branchpoint repeat unit of the (1→3,1→6)-β-D-glucan isolated from <i>C. glabrata ace2</i> strain.

<p>HSQC-TOCSY spectrum indicates assignments and correlations for protons and carbons in the branch point repeat unit based upon correlations initially identified for C3Br (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0027614#pone-0027614-g002" target="_blank">Figure 2</a>).</p