Characterising phosphorus and nitrate inputs to a rural river using high-frequency concentration-flow relationships.

The total reactive phosphorus (TRP) and nitrate concentrations of the River Enborne, southern England, were monitored at hourly interval between January 2010 and December 2011. The relationships between these high-frequency nutrient concentration signals and flow were used to infer changes in nutrient source and dynamics through the annual cycle and each individual storm event, by studying hysteresis patterns. TRP concentrations exhibited strong dilution patterns with increasing flow, and predominantly clockwise hysteresis through storm events. Despite the Enborne catchment being relatively rural for southern England, TRP inputs were dominated by constant, non-rain-related inputs from sewage treatment works (STW) for the majority of the year, producing the highest phosphorus concentrations through the spring-summer growing season. At higher river flows, the majority of the TRP load was derived from within-channel remobilisation of phosphorus from the bed sediment, much of which was also derived from STW inputs. Therefore, future phosphorus mitigation measures should focus on STW improvements. Agricultural diffuse TRP inputs were only evident during storms in the May of each year, probably relating to manure application to land. The nitrate concentration-flow relationship produced a series of dilution curves, indicating major inputs from groundwater and to a lesser extent STW. Significant diffuse agricultural inputs with anticlockwise hysteresis trajectories were observed during the first major storms of the winter period. The simultaneous investigation of high-frequency time series data, concentration-flow relationships and hysteresis behaviour through multiple storms for both phosphorus and nitrate offers a simple and innovative approach for providing new insights into nutrient sources and dynamics.

Assessment of bevacizumab conjugated to Cy5.5 for detection of head and neck cancer xenografts.

Optical fluorescent technology has the potential to deliver real time imaging of cancer into the operating room and the clinic. To determine the efficacy of fluorescently labeled anti-vascular endothelial growth factor (VEGF) antibody to be used as a cancer specific optical contrast agent to guide surgical resections, we evaluated the sensitivity and specificity of this agent to detect microscopic residual disease in a preclinical model of head and neck squamous cell carcinoma (HNSCC). Using a flank murine model, mice were xenografted with SCC-1 tumor cells and injected with anti-VEGF antibody (bevacizumab) conjugated to an optically active fluorophore (Cy5.5). Tumors underwent sub-total resections and were assessed for the presence of residual disease by fluorescent stereomicroscopy. Expected positive and negative biopsies were taken according to the presence or absence of fluorescence, respectively. Histology was used to confirm the presence or absence of disease. Biopsies taken from areas of fluorescence within the wound bed (n=18) were found to be histologically malignant in all but one biopsy. Samples taken from a non-fluorescing tumor bed (n=15) were found to be histologically benign in 11 of 15. These findings correlated with a sensitivity and specificity of 80.9% and 91.7%, respectively. This data supports previous data presented by this group and supports further investigation of fluorescently labeled anti-tumor antibodies to detect disease in the surgical setting.

Retrospective study of mercury in raccoons (Procyon lotor) in south Florida.

Museum and recent collections of raccoon hair were used to assess whether temporal or spatial trends existed in MMHg distributions in south Florida. The hypothesis that MMHg in raccoon hair had remained the same since 1947 could not be rejected. Some sampling regions showed increases while others did not. However, large differences existed between sites, amounting to a factor of 20 for raccoons collected during 2000 and during the period prior to 1960 (museum samples). Raccoon feeding behavior and the production of MMHg most probably accounted for the spatial differences. Large differences in MMHg concentrations existed in different tissues ranging in order of hair, liver, kidney, muscle, heart, brain, and blood in their respective ratios to blood: 96:10:6:5:4:2.5:1. Liver Hg is 7% MMHg, while hair Hg is 99% MMHg. These associations appear largely regulated by metabolic processes. Speciation of Hg is very important for gaining an understanding of ecosystem and organism Hg dynamics. Further work is needed to establish whether Se plays a role in Hg sequestration and whether hair Hg is a good surrogate for estimating Hg concentrations in other tissues in south Florida raccoon populations.

A computationally directed screen identifying interacting coiled coils from Saccharomyces cerevisiae.

Computational methods can frequently identify protein-interaction motifs in otherwise uncharacterized open reading frames. However, the identification of candidate ligands for these motifs (e.g., so that partnering can be determined experimentally in a directed manner) is often beyond the scope of current computational capabilities. One exception is provided by the coiled-coil interaction motif, which consists of two or more alpha helices that wrap around each other: the ligands for coiled-coil sequences are generally other coiled-coil sequences, thereby greatly simplifying the motif/ligand recognition problem. Here, we describe a two-step approach to identifying protein-protein interactions mediated by two-stranded coiled coils that occur in Saccharomyces cerevisiae. Coiled coils from the yeast genome are first predicted computationally, by using the multicoil program, and associations between coiled coils are then determined experimentally by using the yeast two-hybrid assay. We report 213 unique interactions between 162 putative coiled-coil sequences. We evaluate the resulting interactions, focusing on associations identified between components of the spindle pole body (the yeast centrosome).

Tridimensional personality questionnaire and treatment response in major depressive disorder: a negative study.

BACKGROUND: Recent studies have found that the Tridimensional Personality Questionnaire can be used to help predict antidepressant treatment response in depressed outpatients. As this finding could be of great clinical importance, we attempted to replicate these findings. METHODS: Our study included 199 outpatients with major depressive disorder in an 8-week open trial with fluoxetine 20 mg/day. The Tridimensional Personality Questionnaire (TPQ) was administered to all patients before treatment. RESULTS: There was a significant correlation between pre-treatment scores on the TPQ subscale of harm avoidance and severity of depression at baseline as determined by Hamilton Depression Rating Scale-17 (HAM-D-17) scores. There was no correlation of harm avoidance scores and percent improvement of HAM-D-17 after treatment with fluoxetine. There was also no correlation of baseline HAM-D-17 scores or percent improvement with the subscales of reward dependence and novelty seeking. LIMITATIONS: Our study's limitations include a possible selection bias, lack of controls and fixed dosing of fluoxetine. CONCLUSIONS: In contrast to previous studies, we failed to find a relationship between temperament type as defined by the TPQ and antidepressant response. Our failure to replicate the findings of other studies may in large part be related to the use of different classes of antidepressants. Further studies using similar antidepressants may be helpful to clarify this discrepancy.

Broad-host-range expression vectors that carry the L-arabinose-inducible Escherichia coli araBAD promoter and the araC regulator.

We describe the development and analysis of broad-host-range (BHR) cloning vectors that carry the araC-PBAD controlled expression cassette from Escherichia coli. These plasmids are designed to facilitate l-arabinose-responsive control of target genes in a variety of Gram-negative bacterial hosts. BHR PBAD::lacZ fusions were used to analyze the utility of this controlled expression system in the plant pathogen Agrobacterium tumefaciens. In A. tumefaciens, the level of control afforded is significant, although less stringent than that observed in E. coli. The BHR PBAD vectors offer a useful alternative to currently used controlled expression systems, and can be employed in conjunction with other regulated promoters to simultaneously regulate expression of multiple genes. Addition of a variety of carbon sources, namely C4 acids and the anti-inducer d-fucose, allows modulation of l-arabinose induction. Activation of PBAD expression in A. tumefaciens requires a plasmid-borne copy of araC, and is not affected by endogenous regulators.

Quantitative and qualitative aspects of the hibernation-related reduction of morphine physical dependence in the ground squirrel (Citellus lateralis).

The development of morphine physical dependence in the contrasting brain states of the nonhibernating (NH) vs. the hibernating (H) condition was measured in the ground squirrel hibernator Citellus lateralis. Morphine was infused continuously into the lateral ventricle (3.44, 6.88 and 13.75 micrograms/hr for periods of 1, 3 and 6 days) in NH and H animals, followed by measurement of the naloxone (1 mg/kg s.c.) evoked abstinence syndrome during the NH state (i.e., H animals were tested after arousal to the NH state). The results showed that morphine treatment during the NH state resulted in significant naloxone-evoked abstinence and an overall dose- and duration-related increase in the strength of the abstinence syndrome. By contrast, morphine treatment during hibernation resulted in significantly reduced abstinence compared with that observed after treatment during the NH state, with no significant morphine dose-response or duration-response trends evident. However, H-state morphine treatment did produce a dose-related reduction of hibernation bout duration. The reduction in the strength of dependence during the H state was associated with a qualitative change in the abstinence syndrome, as revealed by exploratory factor analysis. This change was reflected by an approximate reversal of the rank order of abstinence signs. These results demonstrate that hibernation-related changes in central nervous system function significantly reduce the liability for and change the character of the development of morphine dependence.

Energy transfer and trapping in photosystem I reaction centers from cyanobacteria.

A mutant strain of the cyanobacterium Synechocystis 6803, TolE4B, was constructed by genetic deletion of the protein that links phycobilisomes to thylakoid membranes and of the CP43 and CP47 proteins of photosystem II (PSII), leaving the photosystem I (PSI) center as the sole chromophore in the photosynthetic membranes. Both intact membrane and detergent-isolated samples of PSI were characterized by time-resolved and steady-state fluorescence methods. A decay component of approximately 25 ps dominates (99% of the amplitude) the fluorescence of the membrane sample. This result indicates that an intermediate lifetime is not associated with the intact membrane preparation and the charge separation in PSI is irreversible. The decay time of the detergent-isolated sample is similar. The 600-nm excited steady-state fluorescence spectrum displays a red fluorescence peak at approximately 703 nm at room temperature. The 450-nm excited steady-state fluorescence spectrum is dominated by a single peak around 700 nm without 680-nm "bulk" fluorescence. The experimental results were compared with several computer simulations. Assuming an antenna size of 130 chlorophyll molecules, an apparent charge separation time of approximately 1 ps is estimated. Alternatively, the kinetics could be modeled on the basis of a two-domain antenna for PSI, consistent with the available structural data, each containing approximately 65 chlorophyll a molecules. If excitation can migrate freely within each domain and communication between domains occurs only close to the reaction center, a charge separation time of 3-4 ps is obtained instead.

Morphine antinociception in the non-hibernating and hibernating states of the ground squirrel (Citellus lateralis).

Previous work in our laboratory demonstrated a significant reduction in the development of morphine physical dependence during hibernation, suggesting a major change in the ability of morphine to act on the central nervous system (CNS) during this naturally altered state. To further investigate the pharmacological actions of morphine during the hibernating (H) state, the present study recorded skin-twitch response (STR) latency as a measure of morphine antinociception in the golden-mantled ground squirrel (Citellus lateralis) during the non-hibernating (NH) and H states. Our results revealed that morphine antinociception continued to develop in hibernation. Moreover, the magnitude of antinociception displayed was greater during the H state than in the NH state. Tolerance to morphine's antinociceptive effects developed in both states as well. The results of the present study indicate that the hibernation-related reduction in the development of morphine dependence represents a selective, rather than a general, suppression of the CNS pharmacological actions of morphine during the H state.

Self-regulation of mood: strategies for changing a bad mood, raising energy, and reducing tension.

Four studies evaluated the success of behaviors and strategies used to self-regulate bad moods, raise energy, and reduce tension. Study 1 (N = 102) used an open-ended questionnaire to identify behavioral categories. Studies 2 and 4 surveyed a representative sample (N = 308) with a fixed-response questionnaire to quantify behaviors, general strategies, and individual differences. Study 3 used psychotherapist (N = 26) judgments of the likely success of the strategies. Therapist and self-rating converged on success of strategies and gender differences. These studies clarify and confirm previous research findings, particularly gender differences in controlling depression. Exercise appears to be the most effective mood-regulating behavior, and the best general strategy to change a bad mood is a combination of relaxation, stress management, cognitive, and exercise techniques. Results support a 2-dimensional biopsychological model of mood.

Inorganic carbon acquisition by aquatic photolithoatrophs of the Dighty Burn, Angus, U.K.: uses and limitations of natural abundance measurements of carbon isotopes.

The 13 C/12 C ratio (expressed as δ13 C) of benrhic photolithotrophs. in the Dighn Water (= Burn) were measured fur comparison with that of the potential inorganic carhun sources. CO2 and HCO3 - , in the Burn. The Burn water contains an average of 65.7 mmol m-3 CO2 with δ13 C of -14.7% and 1600 mmol m-3 HCO3 - with δ13 C of -4.%. δ13 C values of riparian vegetation were also measured as contributors, after respiration in the soil or the Burn, to the δ13 C of inorganic carbon in the Burn. The potential range of differences in 13 C/12C between dissolved CO2 and plant organic C is set by the intrinsic 13 c/12 C discrimination (α value) in CO2 fixation by Rubisco. Main results and conclusions are. as follows, (i) A literature survey suggests that there is no convincing evidence that the α, Values (rate constant for 12 CO2 fixation relative to that for 13 CO2 fixation by Rubisco in the absence of CO2 transport limitation) for the'lower plants'in the Burn (diatoms, green and red algae, mosses) are significantly different from the well-established αp values for the flowering plum enzyme. (ii) In confirmation of earlier work, the semi-erect 'streamer'gametophytes of the red alga Lemanea mamillosa and the moss Fontinalis antipyetica have δ13 C values which can only be interpreted in terms of diffusive CO2 entry with minimal limitation of photosynthesis by CO- diffusion, (iii) The serui-erect grren alga Cladophora glomerata and the flowering plant Ranunculus penicillatus ssp. pseudofluitons (formerly var. calcareus) are- both able to use HCO3 - . Their δ13 C values indicate that, if the HCO3 - -use system does not (as is likely) discriminate significantly between 13 C and 12 C, then a substantial fraction of the inorganic C made available to Rubisco must return to the medium, carrying 13 C-inorganic C not fixed by Rubisco. (iv) Two sets of δ13 C data from different hydrodynamic regimes distance from leading edge of a flat stone; different size of thalli) show that the attainable differences in situ in thickness of the diffusion boundary layer do not alter the fractional limitation of photosynthesis of Cladophora by external diffusion of inorganic C, considered with HCO3 use. (vi) The entrusting red alga Hildenbrandia rivularis has a δ13 C value suggestive of CO2 as the inorganic C source, but not entirely ruling nut HCO3 - . Marine species of both Hildenbrundia and Cladophora have δ13 C values which, even when corrected for source inorganic C δ13 C values, are 10%, more positive than the freshwater species. (vii) Mats of pennate diatoms were shown by pH-drift to by able to use HCO3 - ; the relatively high (i.e. not very negative) δ12 C value of these mats could relate to a relatively'non-leaky'HCO3 - aequisition mechanism and/or to limitation by external diffusion (e.g. through the mat).

Changes in striatal dopamine metabolism during the development of morphine physical dependence in rats: observations using in vivo microdialysis.

The present study examined the effect of prolonged morphine treatment on striatal dopamine (DA) release and metabolism, during the initial phase of the development of morphine dependence. Sprague-Dawley rats were implanted with chronic guides for microdialysis of the striatum. Morphine (two 75-mg pellets, subcutaneous implant) or placebo was given (12 hr) to pentobarbital anesthetized animals. Following recovery from anesthesia, morphine physical dependence was verified by the naloxone-evoked abstinence syndrome. Morphine produced significant increases in the dialysate level of DA nad its metabolites (DOPAC and HVA) above baseline compared to placebo treatment. HVA levels began to increase immediately following morphine administration, whereas DA and DOPAC levels began to increase after a latency of one and three hr, respectively. Morphine effects on striatal DA metabolism included changes in the metabolic disposition of DA. Increases in HVA concentration accompanied increases in DOPAC concentration up to a threshold value of DOPAC efflux; further increases in DOPAC level were associated with decreases in HVA level. These in vivo data suggest that morphine-induced changes in the regulation of striatal dopaminergic function may be an important component of the development of physical dependence.

Effects of acidic deposition and other energy emissions on wildlife: a compendium.

Energy emissions, including acidic depositions, pose potential problems for wildlife populations. Historical and recent events show both direct, acute effects and indirect, chronic effects from a variety of airborne pollutants. Information on effects of selected gaseous and particulate energy emissions on domestic animals and livestock and on wildlife is compared. Our understanding of wildlife effects can be improved by the evaluation of veterinary toxicological information and research on the ecological equivalents of domestic and laboratory animals.

Turnover of acetylcholinesterase in innervated and denervated rat diaphragm.

The acetylcholinesterase (AChE) in rat diaphragms was labelled by intravenous injection of echothiophate in order to evaluate the turnover of AChE in innervated and denervated muscle in vivo. Echothiophate diethylphosphorylates AChE thereby inactivating it. Labelled (diethylphosphorylated) enzyme is rapidly and quantitatively reactivated with 1-methyl-2-hydroxyiminomethylpyridinium (2-PAM), so labelled (diethylphosphorylated) AChE was conveniently measured as 2-PAM-reactivatable AChE activity. In homogenates in vitro, label is lost spontaneously (diethylphosphorylated AChE spontaneously reactivates) with a half-time of 27 h. In innervated diaphragm, labelled non-end-plate AChE is lost with a half-time of 13 h. When correction is made for the spontaneous loss of label on the basis of in vitro measurements, this data indicates that non-end-plate AChE turns over with a half-time of about 26 h. In innervated diaphragm, labelled end-plate-specific AChE is lost more slowly than non-end-plate AChE and at a rate essentially identical to the rate of spontaneous loss of label in vitro. The rate of loss of labelled non-end-plate AChE is essentially identical in 18 h denervated and in paired innervated diaphragms. The rate of loss of labelled end-plate-specific AChE is significantly faster in 18 h denervated diaphragms than in paired innervated diaphragms. On the basis of these observations, hypotheses concerning the mechanisms of the denervation-induced decreases in non-end-plate and end-plate-specific AChE are formulated and discussed.