Designing monitoring programs for chemicals of emerging concern in potable reuse--what to include and what not to include?

This study discussed a proposed process to prioritize chemicals for reclaimed water monitoring programs, selection of analytical methods required for their quantification, toxicological relevance of chemicals of emerging concern regarding human health, and related issues. Given that thousands of chemicals are potentially present in reclaimed water and that information about those chemicals is rapidly evolving, a transparent, science-based framework was developed to guide prioritization of which compounds of emerging concern (CECs) should be included in reclaimed water monitoring programs. The recommended framework includes four steps: (1) compile environmental concentrations (e.g., measured environmental concentration or MEC) of CECs in the source water for reuse projects; (2) develop a monitoring trigger level (MTL) for each of these compounds (or groups thereof) based on toxicological relevance; (3) compare the environmental concentration (e.g., MEC) to the MTL; CECs with a MEC/MTL ratio greater than 1 should be prioritized for monitoring, compounds with a ratio less than '1' should only be considered if they represent viable treatment process performance indicators; and (4) screen the priority list to ensure that a commercially available robust analytical method is available for that compound.

Biochemical and toxicopathic biomarkers assessed in smallmouth bass recovered from a polychlorinated biphenyl-contaminated river

Smallmouth bass (Micropterus dolomieu) were collected to quantify the nature and prevalence of biomarker responses, including biochemical indices, toxicopathic lesions and general health indices, among fish collected from polychlorinated biphenyl (PCB)-contaminated and nearby uncontaminated reaches of the Kalamazoo River, Michigan, USA. Blood and tissue samples (gill, liver, spleen, head kidney, trunk kidney, thyroid and gonads) were collected and preserved at necropsy for biochemical and histological analyses. The body condition factor and liver somatic index were significantly lower in fish collected from the downstream, contaminated site. Plasma vitellogenin was not detected in male fish collected from either site. Liver ethoxyresorufin-O-deethylase activity and liver and spleen superoxide dismutase activity were significantly depressed in fish collected from the downstream site. Significant toxicopathic lesions such as glycogen depletion, enhanced macrophage aggregates, hepatic foci of cellular alteration (i.e. preneoplastic lesions) and neoplasia were also detected in the liver of fish collected from the downstream site. This study indicates that many of the biochemical and histopathological biomarker responses were associated with liver and body tissue PCB concentrations. Taken together, the biomarkers of exposure and effect strongly suggest that fish within the downstream site are adversely affected by PCBs and other chemical stressors.

Determining the identity and purity of recombinant proteins by UV absorption spectroscopy

Because each protein (gene product) has a unique amino acid sequence, the particular aromatic amino acid content of each protein results in a unique spectrum in the near-UV (250 to 350 nm) region. The highly specific microenvironment experienced by each aromatic residue in the three-dimensional protein matrix results in fine shifts in a protein's spectrum. This unit provides protocols for the detection and analysis of UV spectra of recombinant proteins and their peptide fragments. The unique UV spectral properties of proteins can in turn be used to assess their purity. This application is inherent in the use of a diode array detector to monitor the effluent from a high-performance liquid chromatography (HPLC) column. A protocol using this technique to assess the purity of recombinant proteins is presented.

Biotechnology core laboratories: An overview

An assessment of the capabilities of biotechnology core facilities requires access to current data on state-of-the-art technologies, personnel, space, services, financial issues, and the demand for such facilities. Data on these topics should be useful to researchers, facility personnel, administrators, and granting agencies.To obtain such data, the Association of Biomolecular Resource Facilities (ABRF) conducted a general survey on the operation and technical capabilities of core facilities. A total of 81 ABRF core laboratories voluntarily responded to the survey. Just over 60% of the respondents were from academic institutions, with the remaining located in research institutes, industry, and one U.S. government laboratory. Fifty laboratories provided financial data, with 47 of these operating on a nonprofit basis. Four laboratories were fully self-supporting from user fees.A typical facility had three full-time staff members and occupied approximately 1100 square feet (ft(2)). The most frequently offered services were N-terminal protein sequencing, protein fragmentation, peptide synthesis and purification, amino acid analysis, DNA synthesis, and DNA sequencing. One third of the facilities provided mass analysis by matrix-assisted laser desorption and ionization (MALDI) mass spectrometry, a recently introduced service that has been offered on an average for 3 years. Another relatively new service, bioinformatics support, is offered by about one third of the responding laboratories.

Serum vitellogenin levels and reproductive impairment of male Japanese Medaka (Oryzias latipes) exposed to 4-tert-octylphenol

The induction of synthesis of the "female" yolk precursor protein vitellogenin (VTG) in male fish by estrogenic chemicals in the environment has been demonstrated in many recent reports. However, little is known about the organismal and biological significance of this phenomenon. To examine the relationship between VTG production in male fish and reproductive impairment, adult male medaka were exposed to 4-tert-octylphenol (OP), a known environmental estrogen, in concentrations ranging from 20 to 230 ppb for 21 days, under flow-through conditions. Following exposure, male fish were mated, in the absence of OP, with unexposed females. Breeding groups composed of exposed males and control females produced about 50% fewer eggs than control groups. VTG levels in serum of male fish increased with increasing OP exposure concentration and decreased after OP exposure was discontinued. Nevertheless, significant correlations (p<0.01) were observed between VTG levels in exposed male fish and 1) OP exposure concentrations, 2) percent of fertilized eggs, and 3) survival of embryos. OP-induced VTG synthesis and reproductive impairment appear to be closely linked phenomena. Histological examination indicated spermatogenesis in OP-exposed fish was inhibited, and some exposed fish had oocytes in their testes. Finally, OP caused a significant increase in the number of abnormally developing embryos, suggesting that OP may be genotoxic as well as estrogenic.

Association of 70-kilodalton heat-shock cognate proteins with acclimation to cold

Exposure of young spinach seedlings (Spinacia oleracea L. cv Bloomsdale) to 5 degrees C leads to an increase in the synthesis of several 79-kilodalton proteins that are present in leaf tissue grown at 20 degrees C. Protein sequence analyses and immunological cross-reactivity indicate that this group of proteins belongs to the 70-kilodalton heat-shock family. Steady-state transcript levels and protein synthesis are increased two- to threefold within 1 day, but immunoblot analyses suggest that the steady-state concentration of this protein group in leaf tissue only gradually accumulates at low temperature. It is proposed that the increased synthesis of several members of the 70-kilodalton heat-shock family could result from an influence of low temperature on protein folding and/or assembly processes.