Biochemical biomarkers in chronically metal-stressed daphnids

Biochemical biomarkers are a popular measure of toxic effects on organisms due to their assumed fast response, and are usually assessed after acute exposure of the organism to the stressor. However, increasing interest in the use of biochemical biomarkers in environmental pollution monitoring calls for more laboratory long-term studies of contaminants' effects on biochemical endpoints. In this study, four biochemical biomarkers (protein content, activity of cholinesterase (ChE), catalase (CAT) and glutathione S-transferase (GST), were correlated with standardised reproductive and survival endpoints of water fleas (Daphnia magna) after chronic exposure to Cr (VI) and Cd. No effect on the reproduction and survival was noticed up to the highest tested concentration of Cr (VI) (52.5 microg/L), while the protein content, and the ChE and CAT activity decreased, and GST activity increased. Cd affected reproduction of daphnids above 0.656 microg/L, but the protein content and ChE activity were changed at 0.328 microg/L and 0.082 microg/L of Cd, respectively. Biochemical biomarkers in some cases proved to be equally or more sensitive than reproduction and mortality. We recommend more frequent use of a battery of biochemical biomarkers in combination with other higher-level biomarkers also in chronic studies and not only in the acute ones.     

Do antennule and aesthetasc structure in the crayfish Orconectes virilis correlate with flow habitat?

The local flow environment affects the shape of waterborne chemical signals through a variety of physical mechanisms and at several scales. Since crayfish rely on these chemical signals to extract information about predators, prey, and mates, one might expect the chemical sensors (aesthetascs) on crayfish antennules to be physically tuned to the presentation of chemical cues by the flow environment. This hypothesis was tested by comparing length, diameter, and spacing of antennules and aesthetascs among geographically distinct populations of Orconectes virilis. Crayfish were collected from the Chagrin river, Hebron hatchery, and Burt lake. In addition, antennules were sampled from 43 museum populations representing 12 lake, 10 creek, and 21 river populations from multiple states and river drainages. Mean velocities from the collection sites were either measured directly or calculated from United States Geological Survey (USGS) historical data. Structural parameters were measured using Scion Image software on Scanning electron microscope micrographs, and analyses of variance were performed using StatView. Structural parameters of aesthetascs were found to vary with flow environment. Aesthetascs from lake populations were inserted at a larger angle, extended out farther from the supporting antennule relative to the width of the antennule, and were more widely spaced than aesthetascs from creek, hatchery, and river populations.     

High-throughput process development: determination of dynamic binding capacity using microtiter filter plates filled with chromatography resin

Steadily increasing demand for more efficient and more affordable biomolecule-based therapies put a significant burden on biopharma companies to reduce the cost of R&D activities associated with introduction of a new drug to the market. Reducing the time required to develop a purification process would be one option to address the high cost issue. The reduction in time can be accomplished if more efficient methods/tools are available for process development work, including high-throughput techniques. This paper addresses the transitions from traditional column-based process development to a modern high-throughput approach utilizing microtiter filter plates filled with a well-defined volume of chromatography resin. The approach is based on implementing the well-known batch uptake principle into microtiter plate geometry. Two variants of the proposed approach, allowing for either qualitative or quantitative estimation of dynamic binding capacity as a function of residence time, are described. Examples of quantitative estimation of dynamic binding capacities of human polyclonal IgG on MabSelect SuRe and of qualitative estimation of dynamic binding capacity of amyloglucosidase on a prototype of Capto DEAE weak ion exchanger are given. The proposed high-throughput method for determination of dynamic binding capacity significantly reduces time and sample consumption as compared to a traditional method utilizing packed chromatography columns without sacrificing the accuracy of data obtained.     

Expression pattern of peptidylarginine deiminase in rat and human Schwann cells

The peptidylarginine deiminase (PAD) family of enzymes are responsible for conversion of protein-bound arginine to citrulline in most tissues of the body and are garnering increased interest for their physiological and pathological roles. Although it has been shown that oligodendrocytes of the CNS express the PAD isoenzyme type 2, nothing is presently known about PAD expression in Schwann cells, the myelinating cells of the PNS. To evaluate PAD expression in the PNS, cultivated rat and human Schwann cells and slices of fetal, juvenile, and normal and regenerated adult sciatic nerves were examined with RT-PCR, Western blot, and immunohistochemical analysis. Samples from cerebellar cultures and skin served as positive controls. One of the principle findings was that cultivated Schwann cells expressed significant levels of mRNA and protein for the PAD isoenzymes 2 and 3. PAD1 and PAD4, however, were not expressed in any types of Schwann cells. Using double immunofluorescence, the majority of PAD2 staining was localized in immature cell stages. Moreover, increased amounts of PAD2, PAD3, and peptidyl-citrulline were also found in human fetal and rat juvenile and regenerated sciatic nerves as compared to similar normal adult specimens. Neuronal and inducible nitric oxide synthases, enzymes that convert free arginine to citrulline, were also expressed in Schwann cells; however, their massive induction by LPS/K(+), was not reflected in an enhanced peptidyl-citrulline immunosignal. These data suggest that, similar to the CNS, citrullination of proteins may also exert a specific role in thecourse of PNS development and repair.     

Validation of a Preclinical Drug Screening Platform for Pharmacoresistant Epilepsy

The successful identification of promising investigational therapies for the treatment of epilepsy can be credited to the use of numerous animal models of seizure and epilepsy for over 80 years. In this time, the maximal electroshock test in mice and rats, the subcutaneous pentylenetetrazol test in mice and rats, and more recently the 6 Hz assay in mice, have been utilized as primary models of electrically or chemically-evoked seizures in neurologically intact rodents. In addition, rodent kindling models, in which chronic network hyperexcitability has developed, have been used to identify new agents. It is clear that this traditional screening approach has greatly expanded the number of marketed drugs available to manage the symptomatic seizures associated with epilepsy. In spite of the numerous antiseizure drugs (ASDs) on the market today, the fact remains that nearly 30% of patients are resistant to these currently available medications. To address this unmet medical need, the National Institute of Neurological Disorders and Stroke (NINDS) Epilepsy Therapy Screening Program (ETSP) revised its approach to the early evaluation of investigational agents for the treatment of epilepsy in 2015 to include a focus on preclinical approaches to model pharmacoresistant seizures. This present report highlights the in vivo and in vitro findings associated with the initial pharmacological validation of this testing approach using a number of mechanistically diverse, commercially available antiseizure drugs, as well as several probe compounds that are of potential mechanistic interest to the clinical management of epilepsy.     

Evaluation of the roles of two compatible solutes,glycine betaine and trehalose,for the Acacia senegal–Sinorhizobium symbiosis exposed to drought stress

Plant and Soil - Acacia senegal (Mimosoideae) is a leguminous, nitrogen-fixing tree that grows in arid areas of Africa and the Near East. In this work, we studied the effects of drought stress on...     

Nasal lavage fluid and proteomics as means to identify the effects of the irritating epoxy chemical dimethylbenzylamine.

The aims of this study were to describe the changes in the nasal lavage fluid (NLF) protein pattern after exposure to the irritating epoxy chemical dimethylbenzylamine (DMBA) and to identify the affected proteins using a proteomic approach. The protein patterns of NLF from six healthy subjects and eight epoxy workers with airway irritation were analysed using two-dimensional gel electrophoresis (2-DE) before and after exposure to 100 microg m(-3) DMBA for 2 h in an exposure chamber. NLF proteins were identified by (i) comparison with a 2-DE NLF reference database; (ii) N-terminal amino acid sequencing; and (iii) mass spectrometry. In NLF from healthy subjects, the levels of immunoglobulin A increased and the levels of Clara cell protein 16 (CC16) decreased after chamber exposure, while in NLF from epoxy workers, alpha(2)-macroglobulin and caeruloplasmin increased. Two previously unidentified proteins decreased in NLF from epoxy workers after exposure; these were identified as statherin and calgranulin B. In addition, the subjects who developed high counts of eosinophils in their nasal mucosa after chamber exposure had significantly lower levels of immunoglobulin-binding factor (IgBF) before exposure than subjects with low eosinophil infiltration. These results show that short-term exposure to DMBA causes distinct changes in NLF proteins. Moreover, three proteins that have previously not been associated with upper airway irritation were identified: statherin, calgranulin B and IgBF. Further studies are needed to investigate whether these proteins may be used as biomarkers of airway irritation and to give new insight into the ways in which occupational exposure to irritants causes inflammation of the airways.     

DNA in Action: Rapid Application of DNA Variation to Sockeye Salmon Fisheries Management

Commitment to conservation-based management of exploited fish species imposes unprecedented requirements for adaptive, real-time management of biologically and socially complex mixed-stock fisheries such as those conducted for Pacific salmon. Stock identification is a key component of the management process, with population-specific timing and abundance information often incorporated into management decisions. By using both microsatellite and major histocompatibility complex genetic variation, we achieved highly accurate estimates of stock composition for Fraser River sockeye salmon. Over a 2-month period in 2002, we analyzed 9300 returning Fraser River sockeye salmon sampled in mixed-stock fisheries, and provided stock composition estimates to fishery managers within 9–30 h of sample delivery. Stock-specific exploitation targets governed by conservation concerns were achieved in this fishery.