No abstract

Simple, rapid and reliable methods are required to monitor the microbial community change in aquatic pond for better animal performance. Four floc (suspended organic matter) samples were collected from outdoor raceways and tanks used for culturing Pacific white shrimp Litopenaeus vannamei. Twenty‐two chlorophyll (Chl) and carotenoid pigments were separated, identified and quantified using high‐performance liquid chromatography–ultraviolet/Vis‐mass spectrometry in the freeze‐dried floc samples. Algal community composition (diatoms, chlorophytes, cyanobacteria, dinoflagellates and cryptophytes) was determined by measuring concentrations of the respective taxonomic biomarkers (carotenoid fucoxanthin, lutein, zeaxanthin, peridinin and alloxanthin) as independent variables and Chl a as the dependent variable using a multiple regression model. This analysis found that the phytoplankton community of the floc samples from two groups of shrimp tanks (32 g L−1‐salinity) were diatom‐dominated (81.7% and 84.4%); and two floc samples from shrimp raceways (5 and 18 g L−1‐salinity) were chlorophyte‐dominated (75.4% and 82.3%). Assessment of total algal and bacterial biomass by quantification of Chl a and muramic acid, respectively, indicated that the 18 g L−1‐salinity raceway sample was bacteria‐dominated, whereas the other three floc samples were algae‐dominated. Sample protein quality was evaluated by its essential amino acid (AA) score and index. Arginine and lysine were found to be the two most limiting AAs for all floc samples.

Background: TRPM7 channels are key regulators of cell growth and proliferation. Results: A natural compound from a Hawaiian soft coral blocks TRPM7 currents and inhibits proliferation. Conclusion: Waixenicin A represents the first potent and relatively specific inhibitor of TRPM7 ion channels. Significance: Waixenicin A or structural analogs may have cancer-specific therapeutic potential.

The transient receptor potential melastatin 7 (TRPM7) is a protein that combines an ion channel with an intrinsic kinase domain, enabling it to modulate cellular functions either by conducting ions through the pore or by phosphorylating downstream proteins via its kinase domain. In the present study, we report store-operated calcium entry (SOCE) as a novel target of TRPM7 kinase activity. TRPM7-deficient chicken DT40 B lymphocytes exhibit a strongly impaired SOCE compared to wild-type cells as a result of reduced calcium release activated calcium currents, and independently of potassium channel regulation, membrane potential changes or changes in cell-cycle distribution. Pharmacological blockade of TRPM7 with NS8593 or waixenicin A in wild-type B lymphocytes results in a significant decrease in SOCE, confirming that TRPM7 activity is acutely linked to SOCE, without TRPM7 representing a store-operated channel itself. Using kinase-deficient mutants, we find that TRPM7 regulates SOCE through its kinase domain. Furthermore, Ca influx through TRPM7 is essential for the maintenance of endoplasmic reticulum Ca concentration in resting cells, and for the refilling of Ca stores after a Ca signalling event. We conclude that the channel kinase TRPM7 and SOCE are synergistic mechanisms regulating intracellular Ca homeostasis.