Trypsinogen hL expressed in the human lung is a new member of the trypsinogen family

Proteomic analysis of whole-body responses in medaka (Oryzias latipes) exposed to benzalkonium chloride

Benzalkonium chloride (BAC) is a cationic surfactant commonly used as a disinfectant, and is discharged into the aquatic environment by various water sources such as wastewater. BAC may also interact with potentially toxic substances such as persistent organic chemicals. Although studies of BAC contamination toxicity and bioaccumulation have been widely reported, the biochemical responses to BAC toxicity remain incompletely understood, and the detailed molecular mechanisms are largely unknown. In this study, two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry-based proteomic approaches were applied to investigate the protein profiles in Oryzias latipes (medaka) chronically exposed to BAC. Fish were exposed to three different concentrations of BAC, 0.05, 0.1, and 0.2 mg/L, for 21 days. A total of 20 proteins involved in the cytoskeleton, the oxidative stress response, the nervous and endocrine systems, signaling pathways, and cellular proteolysis were significantly upregulated by BAC exposure. The proteomic information obtained in the present study will be useful in identification of potential biomarkers for BAC toxicity, and begins to elucidate its molecular mechanisms, providing new insights into the ecotoxicity of BAC.

Differential gene expression in anthracene-exposed mummichogs (Fundulus heteroclitus)

The polycyclic aromatic hydrocarbon (PAH) anthracene is present in many estuarine systems at concentrations believed to cause sublethal adverse effects, although its exact mode of toxicity remains unclear. Knowledge of the induction or suppression of specific genes as a result of exposure may be useful in explaining these effects. We have generated a fingerprint of anthracene exposure using the mummichog (Fundulus heteroclitus), a non-migratory estuarine fish species. The fish were exposed in 7-day static renewal tests to environmentally relevant concentrations of 0, 27, 50, and 80 microg/l of anthracene. Total RNA was extracted from the livers and differential display reverse transcription polymerase chain reaction (DD RT-PCR) was used to recover 26 differentially expressed cDNA fragments. These cDNAs were isolated, sequenced, and compared to sequences of known genes in order to identify possible physiological consequences of exposure to anthracene. We then constructed macroarrays using these fragments and probed them with RNA from both anthracene-exposed fish and fish from a known PAH-impacted site. Three genes appear to be good indicators of exposure to anthracene in the range of concentrations tested, which included CYP2N2 and two expressed sequence tags (ESTs) termed 15C1 and 18C2. The expression of nine genes was altered in fish collected from a site with multiple PAHs. Band 15C1 and CYP2N2 again showed statistically significant upregulation in the field-caught fish, while a trypsin precursor and fatty acid-binding protein (FABP) all showed similar trends in induction as the laboratory-exposed fish. Further insight into the mechanism of toxicity of contaminants will be gained by the ability to identify and use differentially expressed genes as markers of exposure and effects.

Trypsinogen hL is not a new member of the human trypsinogen family, but a known mouse ortholog

An allegedly novel human trypsinogen cDNA clone termed trypsinogen hL was recently reported in the Biological & Pharmaceutical Bulletin (2003; 26: 361-364). This "new" trypsinogen sequence was isolated by PCR using human lung cDNAs as template and was presumed to be a new member of the human trypsinogen family. However, trypsinogen hL does not match any sequence in the human genome; whereas it is 100% identical to mouse trypsinogen 7. Thus, trypsinogen hL is not of human origin, and its cloning from a human cDNA library was clearly a result of contamination with mouse genetic material. Publication of this cloning artifact could have been avoided by a simple BLAST search of GenBank or other sequence databanks.