FIRST HARMFUL DINOPHYSIS (DINOPHYCEAE,DINOPHYSIALES) BLOOM IN THE U.S. IS REVEALED BY AUTOMATED IMAGING FLOW CYTOMETRY1

Imaging FlowCytobot (IFCB) combines video and flow cytometric technology to capture images of nano‐ and microplankton (～10 to >100 μm) and to measure the chlorophyll fluorescence associated with each image. The images are of sufficient resolution to identify many organisms to genus or even species level. IFCB has provided >200 million images since its installation at the entrance to the Mission‐Aransas estuary (Port Aransas, TX, USA) in September 2007. In early February 2008, Dinophysis cells (1–5 · mL^?1) were detected by manual inspection of images; by late February, abundance estimates exceeded 200 cells · mL^?1. Manual microscopy of water samples from the site confirmed that D. cf. ovum F. Schütt was the dominant species, with cell concentrations similar to those calculated from IFCB data, and toxin analyses showed that okadaic acid was present, which led to closing of shellfish harvesting. Analysis of the time series using automated image classification (extraction of image features and supervised machine learning algorithms) revealed a dynamic phytoplankton community composition. Before the Dinophysis bloom, Myrionecta rubra (a prey item of Dinophysis) was observed, and another potentially toxic dinoflagellate, Prorocentrum, was observed after the bloom. Dinophysis cell‐division rates, as estimated from the frequency of dividing cells, were the highest at the beginning of the bloom. Considered on a daily basis, cell concentration increased roughly exponentially up to the bloom peak, but closer inspection revealed that the increases generally occurred when the direction of water flow was into the estuary, suggesting the source of the bloom was offshore.     

Addressing the design of in vitro models for the investigation of microcystins: The essential role of transporter‐mediated uptake

This article discusses the need for transporter‐mediated uptake for investigations addressing the mechanism of action of microcystins [with reference to the previous article in Cell Biology International by de Souza Votto (2007) 31:1359–1366].     

Retraction: Fu,W., Wang,W., Wang,H., Zhu,X., Liang,Y., Kung,H. and Zhang,J. (2014), 1,3,5‐Trihydroxy‐13,13‐dimethyl‐2H‐pyran [7,6‐b] xanthone directly targets heat shock protein 27 in hepatocellular carcinoma. Cell Biol Int, 38: 272–276. doi:10.1002/cbin.10193

The above article from Cell Biology International, published online on 07 October 2013 in Wiley Online Library ( wileyonlinelibrary.com ) has been retracted by agreement between the authors, the journal Editor‐in‐Chief and John Wiley & Sons Ltd. The retraction has been agreed due to an error in the detection method used.     

Book Review

Peroxidases in Chemistry and Biology, Vols. 1 and 2 Edited by J EVERSE, K E EVERSE & M B GRISHAM CRC Press, Boca Raton, Florida, 1991

The Cell Biology of Inflammation in the Gastrointestinal Tract edited by T.J. Peters. Corners Publications, Hull, U.K. pp. xvii + 389. Price £39.00     

The ancillary protein 1 of Streptococcus pyogenes FCT-1 pili mediates cell adhesion and biofilm formation through heterophilic as well as homophilic interactions

Gram‐positive pili are known to play a role in bacterial adhesion to epithelial cells and in the formation of biofilm microbial communities. In the present study we undertook the functional characterization of the pilus ancillary protein 1 (AP1_M6) from Streptococcus pyogenes isolates expressing the FCT‐1 pilus variant, known to be strong biofilm formers. Cell binding and biofilm formation assays using S. pyogenes in‐frame deletion mutants, Lactococcus expressing heterologous FCT‐1 pili and purified recombinant AP1_M6, indicated that this pilin is a strong cell adhesin that is also involved in bacterial biofilm formation. Moreover, we show that AP1_M6 establishes homophilic interactions that mediate inter‐bacterial contact, possibly promoting bacterial colonization of target epithelial cells in the form of three‐dimensional microcolonies. Finally, AP1_M6 knockout mutants were less virulent in mice, indicating that this protein is also implicated in GAS systemic infection.     

AP2α is essential for MUC8 gene expression in human airway epithelial cells

Mucins are high molecular weight proteins that make up the major components of mucus. Hypersecretion of mucus is a feature of several chronic inflammatory airway diseases. MUC8 is an important component of airway mucus, and its gene expression is upregulated in nasal polyp epithelium. Little is known about the molecular mechanisms of MUC8 gene expression. We first observed overexpression of activator protein‐2alpha (AP2α) in human nasal polyp epithelium. We hypothesized that AP2α overexpression in nasal polyp epithelium correlates closely with MUC8 gene expression. We demonstrated that phorbol 12‐myristate 13‐acetate (PMA) treatment of the airway epithelial cell line NCI‐H292 increases MUC8 gene and AP2α expression. In this study, we sought to determine which signal pathway is involved in PMA‐induced MUC8 gene expression. The results show that the protein kinase C and mitogen‐activating protein/ERK kinase (MAPK) pathways modulate MUC8 gene expression. PD98059 or ERK1/2 siRNA and RO‐31‐8220 or PKC siRNA significantly suppress AP2α as well as MUC8 gene expression in PMA‐treated cells. To verify the role of AP2α, we specifically knocked down AP2α expression with siRNA. A significant AP2α knock‐down inhibited PMA‐induced MUC8 gene expression. While dominant negative AP2α decreased PMA‐induced MUC8 gene expression, overexpressing wildtype AP2α increased MUC8 gene expression. Furthermore, using lentiviral vectors for RNA interference in human nasal polyp epithelial cells, we confirmed an essential role for AP2α in MUC8 gene expression. From these results, we concluded that PMA induces MUC8 gene expression through a mechanism involving PKC, ERK1/2, and AP2α activation in human airway epithelial cells. J. Cell. Biochem. 110: 1386–1398, 2010. © 2010 Wiley‐Liss, Inc.     

Transgenic expression of n‐3 fatty acid desaturase (fat‐1) in C57/BL6 mice: Effects on glucose homeostasis and body weight

The fat‐1 gene, derived from Caenorhabditis elegans, encodes for a fatty acid n‐3 desaturase. In order to study the potential metabolic benefits of n‐3 fatty acids, independent of dietary fatty acids, we developed seven lines of fat‐1 transgenic mice (C57/BL6) controlled by the regulatory sequences of the adipocyte protein‐2 (aP2) gene for adipocyte‐specific expression (AP‐lines). We were unable to obtain homozygous fat‐1 transgenic offspring from the two highest expressing lines, suggesting that excessive expression of this enzyme may be lethal during gestation. Serum fatty acid analysis of fat‐1 transgenic mice (AP‐3) fed a high n‐6 unsaturated fat (HUSF) diet had an n‐6/n‐3 fatty acid ratio reduced by 23% (P < 0.025) and the n‐3 fatty acid eicosapentaenoic acid (EPA) concentration increased by 61% (P < 0.020). Docosahexaenoic acid (DHA) was increased by 19% (P < 0.015) in white adipose tissue. Male AP‐3‐fat‐1 line of mice had improved glucose tolerance and reduced body weight with no change in insulin sensitivity when challenged with a high‐carbohydrate (HC) diet. In contrast, the female AP‐3 mice had reduced glucose tolerance and no change in insulin sensitivity or body weight. These findings indicate that male transgenic fat‐1 mice have improved glucose tolerance likely due to increased insulin secretion while female fat‐1 mice have reduced glucose tolerance compared to wild‐type mice. Finally the inability of fat‐1 transgenic mice to generate homozygous offspring suggests that prolonged exposure to increased concentrations of n‐3 fatty acids may be detrimental to reproduction. J. Cell. Biochem. 107: 809–817, 2009. © 2009 Wiley‐Liss, Inc.     

Serotype‐dependent expression patterns of stabilized lipopolysaccharide aggregates in Aggregatibacter actinomycetemcomitans strains

Above a critical concentration, amphiphilic lipopolysaccharide (LPS) molecules in an aqueous environment form aggregate structures, probably because of interactions involving hydrophobic bonds. Ionic bonds involving divalent cations stabilize these aggregate structures, making them resistant to breakdown by detergents. The aim of this study was to examine expression patterns of stabilized LPS aggregates in Aggregatibacter actinomycetemcomitans, a microorganism that causes periodontitis. A. actinomycetemcomitans strains of various serotypes and truncated LPS mutants were prepared for this study. Following treatment with a two‐phase separation system using the detergent Triton X‐114, crude LPS extracts of the study strains were separated into detergent‐phase LPS (DP‐LPS) and aqueous‐phase LPS (AP‐LPS). Repeated treatment of the aqueous phase with the two‐phase separation system produced only a slight decrease in AP‐LPS, suggesting that AP‐LPS was resistant to the detergent and thus distinguishable from DP‐LPS. The presence of divalent cations increased the yield of AP‐LPS. AP‐LPS expression patterns were serotype‐dependent; serotypes b and f showing early expression, and serotypes a and c late expression. In addition, highly truncated LPS from a waaD (rfaD) mutant were unable to generate AP‐LPS, suggesting involvement of the LPS structure in the generation of AP‐LPS. The two‐phase separation was able to distinguish two types of LPS with different physical states at the supramolecular structure level. Hence, AP‐LPS likely represents stabilized LPS aggregates, whereas DP‐LPS might be derived from non‐stabilized aggregates. Furthermore, time‐dependent expression of stabilized LPS aggregates was found to be serotype‐dependent in A. actinomycetemcomitans.     

Purification and Characterization of Acid Phosphatase from the Egg of the Lady Beetle, Harmonia axyridis (Coccinellidae: Coleoptera)

Acid phosphatase (AP) in the egg of the lady beetle, Harmonia axyridis, was purified and characterized. Ammonium sulfate precipitation, CM column and isoelectrofocusing (IEF) were applied to purify an estimated molecular weight of 66 kDa AP. The purity was checked by SDS PAGE, native PAGE and Western blot. AP was detected in the hemolymph of the female and the egg, but not in the male on the blotting. Km of AP for a substrate, p‐nitrophenyl phosphate (p‐NPP), was 1.64 x 10^‐4 M. AP had the optimum enzymatic activity at pH 3.5. In inhibition tests performed with various chemicals, ammonium molybdate suppressed 99% of the enzyme activity of AP even at the concentration of 5 x 10^‐4 mM. AP was stable up to 50°C.     

Bioinformatics analysis in menopause transition promotes distinct modulation in calvaria and bone marrow osteoblastic cells

We read with great interest the recent report by Semeghini et al. (2017), Cell Biol Int, “Menopause transition promotes distinct modulation of mRNAs and miRNAs expression in calvaria and bone marrow osteoblastic cells,” which appeared on 24 May 2017 in Cell Biology International. The results of the report are very helpful for us; however, from our perspective, the author's method in bioinformatics analysis is inappropriate: Student's t‐test is an inappropriate statistical method for detecting differentially expressed mRNA or miRNA in osteoblastic cells from calvaria of ovariectomized rats compared to control or in osteoblastic cells from bone marrow of ovariectomized rats compared to control.     

Clinorotation upregulates inducible nitric oxide synthase by inhibiting AP‐1 activation in human umbilical vein endothelial cells

Alterations of nitric oxide contribute to post‐flight orthostatic intolerance. The aim of this study was to investigate the changes of inducible nitric oxide synthase (iNOS) and the mechanisms underlying regulation of iNOS by simulated microgravity in human umbilical vein endothelial cells (HUVECs). Clinorotation, a simulated‐model of microgravity, increased iNOS expression and promoter activity in HUVECs. The transactivations of NF‐κB and AP‐1 were suppressed by 24 h clinorotation. A key role for AP‐1, but not NF‐κB in the regulation of iNOS was shown. (1) PDTC, a NF‐κB inhibitor, had no effect on clinorotation upregulation of iNOS. (2) SP600125, a JNK‐specific inhibitor, which resulted in inhibition of AP‐1 activity, enhanced the iNOS expression and promoter activity in clinorotation. (3) Overexpression of AP‐1 remarkably attenuated the upregulation effect of clinorotation. These findings indicate that clinorotation upregulates iNOS in HUVECs by a mechanism dependent on suppression of AP‐1, but not NF‐κB. These results support a key role for AP‐1 in the signaling of postflight orthostatic intolerance. J. Cell. Biochem. 107: 357–363, 2009. © 2009 Wiley‐Liss, Inc.     

Essay review: The politics of Writing Biology

Greg Myers, Writing Biology: Texts in the Social Construction of Scientific Knowledge (Madison: University of Wisconsin Press, 1990).