Habitat effects on invertebrate drift in a small trout stream: implications for prey availability to drift-feeding fish

In this study, we focused on the drivers of micro- and mesohabitat variation of drift in a small trout stream with the goal of understanding the factors that influence the abundance of prey for drift-feeding fish. We hypothesized that there would be a positive relationship between velocity and drift abundance (biomass concentration, mg/m³) across multiple spatial scales, and compared seasonal variation in abundance of drifting terrestrial and aquatic invertebrates in habitats that represent the fundamental constituents of stream channels (pools, glides, runs, and riffles). We also examined how drift abundance varied spatially within the water column. We found no relationship between drift concentration and velocity at the microhabitat scale within individual pools or riffles, suggesting that turbulence and short distances between high- and low-velocity microhabitats minimize changes in drift concentration through settlement in slower velocity microhabitats. There were also minimal differences in summer low-flow drift abundance at the mesohabitat scale, although drift concentration was highest in riffle habitats. Similarly, there was no differentiation of drifting invertebrate community structure among summer samples collected from pools, glides, runs, and riffles. Drift concentration was significantly higher in winter than in summer, and variation in drift within individual mesohabitat types (e.g., pools or riffles) was lower during winter high flows. As expected, summer surface samples also had a significantly higher proportion of terrestrial invertebrates and higher overall biomass than samples collected from within the water column. Our results suggest that turbulence and the short length of different habitat types in small streams tend to homogenize drift concentration, and that spatial variation in drift concentrations may be affected as much by fish predation as by entrainment rates from the benthos. Handling editor: Robert Bailey     

Expression and function of T cell homing molecules in Hodgkin’s lymphoma

Circulating T lymphocytes enter a tissue if they express appropriate chemokine receptors and adhesion molecules to engage ligands presented at this site. To aid rational development of T cell-based therapies for Hodgkin's lymphoma (HL), we have assessed the expression and function of homing receptors on tumour-infiltrating T cells in HL and compared them with T cells from unaffected lymph nodes and colorectal cancer tissue. Chemokine receptors CXCR3, CXCR4 and CCR7 were expressed on a large proportion of T cells within HL tissue and mediated chemotaxis to purified chemokine. The corresponding ligands (CXCL10, CXCL12, CCL21) were expressed on the malignant cells and/or vascular endothelium. Adhesion molecules including CD62L were widely expressed on HL-derived T cells and their corresponding ligands were detected on vessels within the tumour. This homing phenotype was distinct from T cells isolated from colorectal cancer, but matched closely the phenotype of T cells from unaffected lymph nodes. Thus, T cell recruitment to HL resembles entry of na?ve/central memory T cells into normal lymph nodes. This has important implications for current approaches to treat HL using T cells activated and expanded in vitro that lack CCR7 and CD62L expression.     

Interactions Between Chronic Stress and Chronic Consumption of Caffeine on the Enzymatic Antioxidant System

We studied the effect of chronic caffeine on parameters related to oxidative stress in different brain regions of stressed and non-stressed rats. Wistar rats were divided into three groups: control (receiving water), caffeine 0.3 g/L and caffeine 1.0 g/L (in the drinking water). These groups were subdivided into non-stressed and stressed (repeated restraint stress during 40 days). Lipid peroxide levels and the total radical-trapping potential were assessed, as well as antioxidant enzyme activities superoxide dismutase, gluthatione peroxidase, and catalase in hippocampus, striatum and cerebral cortex. Results showed interactions between stress and caffeine, especially in the cerebral cortex, since caffeine increased the activity of some antioxidant enzymes, but not in stressed animals. We concluded that chronic administration of caffeine led, in some cases, to increased activity of antioxidant enzymes. However, these effects were not observed in the stressed animals.     

Further studies on the pharmacological features of the nociceptin/orphanin FQ receptor ligand ZP120

ZP120 is a nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP) ligand. In previous studies, the effects of ZP120 were found to be sensitive to J-113397 in mouse tissues while resistant to UFP-101 in rat tissues. The aim of this study was to further investigate the ZP120 pharmacological profile using mouse and rat preparations, J-113397 and UFP-101, as well as NOP receptor knockout (NOP(-/-)) mice. Electrically stimulated mouse and rat vas deferens were used to characterize the pharmacology of ZP120 in vitro. For in vivo studies the tail-withdrawal assay was performed in wild type (NOP(+/+)) and NOP knockout (NOP(-/-)) mice. In the mouse and rat vas deferens ZP120 mimicked the effects of N/OFQ showing higher potency but lower maximal effects. In both preparations, J-113397 antagonized N/OFQ and ZP120 effects showing similar pK(B) values ( approximately 7.8). UFP-101 antagonized the actions of N/OFQ (pK(B) values approximately 7.3) but did not modify the effects of ZP120. The inhibitory effects of N/OFQ and ZP120 were no longer evident in vas deferens tissues taken from NOP(-/-) mice. In NOP(+/+) mice subjected to the tail-withdrawal assay, ZP120 (1 nmol) mimicked the pronociceptive action of N/OFQ (10 nmol), producing longer lasting effects. The effects of both peptides were absent in NOP(-/-) animals. The NOP receptor ligand ZP120 is a high potency NOP selective partial agonist able to evoke long-lasting effects; its diverse antagonist sensitivity in comparison with N/OFQ may derive from different modality of binding to the NOP receptor.     

Short‐term exposure to mobile phone base station signals does not affect cognitive functioning or physiological measures in individuals who report sensitivity to electromagnetic fields and controls

Individuals who report sensitivity to electromagnetic fields often report cognitive impairments that they believe are due to exposure to mobile phone technology. Previous research in this area has revealed mixed results, however, with the majority of research only testing control individuals. Two studies using control and self‐reported sensitive participants found inconsistent effects of mobile phone base stations on cognitive functioning. The aim of the present study was to clarify whether short‐term (50 min) exposure at 10 mW/m² to typical Global System for Mobile Communication (GSM) and Universal Mobile Telecommunications System (UMTS) base station signals affects attention, memory, and physiological endpoints in sensitive and control participants. Data from 44 sensitive and 44 matched‐control participants who performed the digit symbol substitution task (DSST), digit span task (DS), and a mental arithmetic task (MA), while being exposed to GSM, UMTS, and sham signals under double‐blind conditions were analyzed. Overall, cognitive functioning was not affected by short‐term exposure to either GSM or UMTS signals in the current study. Nor did exposure affect the physiological measurements of blood volume pulse (BVP), heart rate (HR), and skin conductance (SC) that were taken while participants performed the cognitive tasks. Bioelectromagnetics 30:556–563, 2009. © 2009 Wiley‐Liss, Inc.     

Weight–length relationships for 54 species of the Arade estuary, southern Portugal

Weight–length relationships (WLRs) are presented for 54 species sampled by several types of fishing gear between February 2004 and May 2007, in the Arade estuary (southern Portugal). WLRs for six species are presented for the first time.     

Use of a low-cost methodology for biodetoxification of castor bean waste and lipase production

The castor bean (Ricinus communis) represents a potential candidate for biodiesel production. The Petrobras Research Center is developing a biodiesel production process from castor bean seeds, in which an unwanted byproduct named castor bean waste is produced. This extremely alkaline waste is toxic and allergenic and, as such, poses a significant environmental problem. Solid-state fermentation (SSF) of castor bean waste was carried out to achieve ricin detoxification, reduce allergenic potential and stimulate lipase production. The fungus, Penicillium simplicissimum, an excellent lipase producer, was able to grow and produce lipase enzyme. After an optimization process, the maximum lipase activity achieved was 44.8 U/g. Moreover, the fungus P. simplicissimum was able to reduce the ricin content to non-detectable levels in addition to diminishing castor bean waste allergenic potential by approximately 16%. In this way, SSF of castor bean waste by P. simplicissimum may increase the utility of the waste by promoting enzyme production and eliminating the principal toxic element, ricin.