SEROTONIN AND NEUROPEPTIDE IMMUNOREACTIVITIES IN THE INTRAMOLLUSCAN STAGES OF 3 MARINE TREMATODE PARASITES

Using an indirect immunofluorescence technique interfaced with confocal scanning laser microscopy, whole-mount preparations of three genera of marine trematode larvae, Cryntocotyle lingua, Cercaria emasculans and Himasthla leptosoma, were screened for 5-hydroxytryptamine (5-HT) and selected neuropeptide immunoreactivities (IRs). IRs for pancreatic polypeptide (PP), peptide YY (PYY) and FMRFamide were found in the central nervous systems of the three species of cercariae, immunostaining the paired ganglia and central commissure and the longitudinal nerve cords, with slight differences in both distribution and intensity of IRs being observed for the different antisera used. PP, PYY and FMRFamide IRs were evident in both central and peripheral components of the nervous system in the rediae of C. lingua. 5-HT IR was confined to the peripheral nervous systems of the cercariae of C. emasculans and the rediae of C. lingua, appearing in the form of a network of immunoreactive fibres and associated large cell bodies. A moderate substance P IR was observed in the nervous system of the cercariae of C. lingua. The patterns of immunostaining described were compared with those obtained using antiserum directed to the C-terminal decapeptide amide of neuropeptide F (NPF), a native parasitic peptide from the cestode Moniezia expansa. Results demonstrated that serotoninergic and peptidergic components were present in the nervous systems of all of the trematode larvae studied and that some, if not all, of the IR for PP. PYY and FMRFamide was due to the presence of a trematode NPF homologue.

Secretion and processing of a novel multi-domain cystatin-like protein by intracellular stages of Trichinella spiralis

The excretory-secretory (ES) proteins of nematode parasites are of major interest as they function at the host-parasite interface and are likely to have roles crucial for successful parasitism. Furthermore, the ES proteins of intracellular nematodes such as Trichinella spiralis may also function to regulate gene expression in the host cell. In a recent proteomic analysis we identified a novel secreted cystatin-like protein from T. spiralis L1 muscle larva. Here we show that the protein, MCD-1 (multi-cystatin-like domain protein 1), contains three repeating cystatin-like domains and analysis of the mcd-1 gene structure suggests that the repeated domains arose from duplication of an ancestral cystatin gene. Cystatins are a diverse group of cysteine protease inhibitors and those secreted by parasitic nematodes are important immuno-modulatory factors. The cystatin superfamily also includes cystatin-like proteins that have no cysteine protease inhibitory activity. A recombinant MCD-1 protein expressed as a GST-fusion protein in Escherichia coli failed to inhibit papain in vitro suggesting that the T. spiralis protein is a new member of the non-inhibitory cystatin-related proteins. MCD-1 secreted from T. spiralis exists as high- and low-molecular weight isoforms and we show that a recombinant MCD-1 protein secreted by HeLa cells undergoes pH-dependent processing that may result in the release of individual cystatin-like domains. Furthermore, we found that mcd-1 gene expression is largely restricted to intracellular stages with the highest levels of expression in the adult worms. It is likely that the major role of the protein is during the intestinal stage of T. spiralis infections.

Carbon distribution within the plant and rhizosphere in laboratory and field-grown Lolium perenne at different stages of development

Carbon distribution within perennial ryegrass was determined at different stages of plant development, by pulse-labelling laboratory and field-grown plants with ¹⁴C-CO₂. During the early stages of growth (23-51 days), C distribution of laboratory grown plants was not markedly affected by plant age, with 12.4-24% of net assimilated label lost into the soil as root-soil respiration. The percentage of net assimilate translocated below ground was 20-28% during this stage of growth. At 65 days, the percentage of the label translocated below ground decreased to 8.1% of the net assimilate, with a subsequent decrease in root-soil respiration to 3.9%. The ability of the plant to fix the label (expressed in MBq g^-1 oven dry total plant weight) decreased steadily as the plants aged. When the 30 day old plants were subjected to water stress (soil water potential -1.5 MPa) for 2 days before pulse-labelling, root-soil respiration of the pulse-label decreased compared with plants grown at field capacity. The distribution of a ¹⁴C pulse-label within perennial ryegrass grown under field conditions was found to be dependent on the age of the plants. For 4 week old plants, 67% of net assimilated label was translocated below ground, with 64.8% of this respired by the roots and soil. Less label was translocated below ground at subsequent pulse-labels from weeks 8 to 24. The proportion of label translocated below ground respired by the roots and soil also decreased. The investment of label in the plant shoots was found to be greater in field grown plants as compared to plants of the same age grown in a controlled, laboratory environment. © 1990.

Effect of temperature on embryonic development, larval viability and biomarkers in the first stages of life of Octopus Vulgaris (Cuvier, 1797)

Dissertação de Mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Shift of spawning season and effects of climate warming on developmental stages of a grayling (Salmonidae)

River-dwelling fish, such as European graylings (Thymallus thymallus), are susceptible to changes in climate because they can often not avoid suboptimal temperatures, especially during early developmental stages. We analyzed data collected in a 62-year-long (1948-2009) population monitoring program. Male and female graylings were sampled about three times/week during the yearly spawning season in order to follow the development of the population. The occurrence of females bearing ripe eggs was used to approximate the timing of each spawning season. In the last years of the study, spawning season was more than 3 weeks earlier than in the first years. This shift was linked to increasing water temperatures as recorded over the last 39 years with a temperature logger at the spawning site. In early spring water temperatures rose more slowly than in later spring. Thus, embryos and larvae were exposed to increasingly colder water at a stage that is critical for sex determination and pathogen resistance in other salmonids. In summer, however, fry were exposed to increasingly warmer temperatures. The changes in water temperatures that we found embryos, larvae, and fry were exposed to could be contributing to the decline in abundance that has occurred over the last 30-40 years.

Linking of stress offset score (SOS), work satisfaction, and organizational commitment to intentions to quit

The purpose of this study was to identify the impact of stressors and offsetting satistiers, measured in this study with Stress Offset Score (SOS), on intentions to quit and examine the mediating and moderating effects of three facets of work satisfaction (job satisfaction, pay satisfaction, and satisfaction with supervisor) and two facets of organizational commitment (affective and nonnative commitment) on this relationship. The sample was composed of 2990 employees from 21 public and private organizations. The interaction of each type of work satisfaction and organizational commitment, with SOS, was tested using Ordinary Least Squares (OLS) procedures. Intentions to quit was the dependent variable. The research questions were determine: (1) Does SOS predict intentions to quit? (2) Does work satisfaction mediate the predictive relationship of SOS on intentions to quit? (3) Does organizational commitment mediate the predictive relationship of SOS on intent to quit? (4) Does work satisfaction moderate the predictive relationship of SOS on intentions to quit? and (5) Does organizational commitment moderate the predictive relationship of SOS on intentions to quit? The results indicated that SOS was negatively correlated with intentions to quit. Each of the types of work satisfaction and organizational commitment variables showed a partial mediated relationship with SOS and each relationship was highly significant, while normative commitment explained more of the relationship then other mediators. The study also tested for interactions but no statistical significant relationships where established between any of the interaction terms (e.g., SOSxJob Satisfaction and SOSxAffcctive Commitment) and intentions to quit.

A constructivist grounded theory of firefighter perceptions of stress, coping and the relationship to health

This qualitative research was a constructivist grounded theory designed to develop an understanding of how firefighters perceive and cope with stressful situations and the impact this has on their perceptions of health. This study was framed in a social ecological perspective with the community of firefighting providing the environment within which to explore stress and coping. Of particular concern here are the stressors associated with firefighting. Prior research with firefighters has often been epidemiological and statistical in nature, focusing on measures of cardiovascular disease, cancer, and depression (Baker & Williams, 2001 ; Brown et al., 2002; Murphy et al.,1999; Regehr et al., 2002; Regehr et al., 2003). Qualitative research examining the perception of stress among firefighters that includes personal stories allows firefighters the opportunity to describe what it is like to be met with physically and mentally challenging situations on a daily basis. Twelve in-depth, semi-structured, face-to-face interviews with a brief questionnaire were conducted with firefighters from a Southern Ontario Fire Department. Four main themes emerged describing the persona of the firefighter, the stressors of firefighters, coping strategies of firefighters, and firefighters' perceptions of health. Stressors include requirements of the job, traumatic calls, tensions with co-workers, the struggle between the family at home and the family at work, political stressors with the City, and the inner struggle. Avoidance coping, approach coping, and gaining perspective emerged as the three coping styles of firefighters. Health was defined as including physical, mental, social and spiritual aspects. A model of the findings is provided that depicts the cyclical nature of the stress-coping-health relationship among firefighters.

Intracellular antioxidant and DNA repair enzymes as correlates of stress resistance and longevity in vertebrates

In animals, both stress resistance and longevity appear to be influenced by the insulin/insulin-like growth factor-l signaling (lIS) pathway, the basic organization of which is highly conserved from invertebrates to vertebrates. Reduced lIS or genetic disruption of the lIS pathway leads to the activation of forkhead box transcription factors, which is thought to upregulate the expression of genes involved in enhancing stress resistance, including perhaps key antioxidant enzymes as well as DNA repair enzymes. Enhanced antioxidant and DNA repair capacities may underlie the enhanced cellular stress resistance observed in long-lived animals, however little data is available that directly supports this idea. I used three. experimental approaches to test the association of intracellular antioxidant and DNA base excision repair (BER) capacities with stress resistance and longevity: (1) a comparison of multiple vertebrate endotherm species of varying body masses and longevities; (2) a comparison of long-lived Snell dwarf mice and their normallittermates; and (3) a comparison of hypometabolic animals undergoing hibernation or estivation with their active counterparts. The activities of the five major intracellular antioxidant enzymes as well as the two rate-limiting enzymes in the BER pathway, apurininc/apyrimidinic (AP) endonuclease and polymerase ~, were measured. These measurements were performed in one or more of the following: (1) cultured dermal fibroblasts; (2) brain tissue; (3) heart tissue; (4) liver tissue. My results indicate that antioxidant enzymes are not universally upregulated in association with enhanced stress resistance and longevity. I also did not find that BER enzyme activity was positively correlated with longevity, in an inter-species context, though there was evidence for enhanced BER in long-lived Snell dwarf mice. Thus, while there were instances in which enhanced antioxidant and BER enzyme activities were associated with increased stress resistance and/or longevity, this was not universally the case, indicating that other mechanisms must be involved. These results suggest the need to re-examine existing 'oxidative stress' hypotheses of longevity and probe further into the molecular physiology of longevity to discover its mechanistic basis.

Atomic diffusion induced by stress relaxation in InGaAs/GaAs epitaxial layers

The origin of the microscopic inhomogeneities in InxGa1-xAs layers grown on GaAs by molecular beam epitaxy is analyzed through the optical absorption spectra near the band gap. It is seen that, for relaxed thick layers of about 2.8μm, composition inhomogeneities are responsible for the band edge smoothing into the whole compositional range (0.05stress relaxation. In consequence, the strain variations present in the layer are converted into composition variations during growth. This process is energetically favorable as it diminishes elastic energy. An additional support to this hypothesis is given by a clear proportionality between the magnitude of the composition variations and the mean strain

Intake, live-weight gain and carcass characteristics of beef cattle given diets based on forage maize silage harvested at different stages of maturity

Advancing maturity of forage maize is associated with increases in the proportion of dry matter (DM) and starch, and decreases in the proportions of structural carbohydrates in the ensiled crop. This experiment investigated the effects of three maize silages of 291 (low), 339 (medium) and 393 (high) g DM per kg fresh weight on the performance of 48 Simmental. Holstein-Friesian cattle. Equal numbers of steers (mean start weight = 503 (s.d. 31.3) kg) and heifers (mean start weight = 378 (s.d. 11.2) kg) were offered individually isonitrogenous diets composed of the three silages plus a protein supplement with minerals once daily until slaughter at the target live weight of 575 and 475 kg for steers and heifers, respectively. Intake was reduced on the low diet (P < 0.01) compared with the other two treatments. Dietary starch intake increased by a total of 1 kg/day between low and medium diets but by only 0.2 kg/day between medium and high diets. Unlike starch intake, total neutral-detergent fibre intake showed no significant difference (P > 0.05) between diets. There were no differences in live-weight gain between treatments but differences (P < 0.05) in food conversion efficiency indicated relative gains of 115, 100 and 102 g gain per kg DM intake for diets low, medium and high, respectively. There were no differences between diets in carcass weights, fat score and overall conformation.

In planta proteomics and proteogenomics of the biotrophic barley fungal pathogen blumeria graminis f. sp hordei

To further our understanding of powdery mildew biology during infection, we undertook a systematic shotgun proteomics analysis of the obligate biotroph Blumeria graminis f. sp. hordei at different stages of development in the host. Moreover we used a proteogenomics approach to feed information into the annotation of the newly sequenced genome. We analyzed and compared the proteomes from three stages of development representing different functions during the plant-dependent vegetative life cycle of this fungus. We identified 441 proteins in ungerminated spores, 775 proteins in epiphytic sporulating hyphae, and 47 proteins from haustoria inside barley leaf epidermal cells and used the data to aid annotation of the B. graminis f. sp. hordei genome. We also compared the differences in the protein complement of these key stages. Although confirming some of the previously reported findings and models derived from the analysis of transcriptome dynamics, our results also suggest that the intracellular haustoria are subject to stress possibly as a result of the plant defense strategy, including the production of reactive oxygen species. In addition, a number of small haustorial proteins with a predicted N-terminal signal peptide for secretion were identified in infected tissues: these represent candidate effector proteins that may play a role in controlling host metabolism and immunity. Molecular & Cellular Proteomics 8: 2368-2381, 2009.

In planta proteomics and proteogenomics of the biotrophic barley fungal pathogen blumeria graminis f. sp hordei

To further our understanding of powdery mildew biology during infection, we undertook a systematic shotgun proteomics analysis of the obligate biotroph Blumeria graminis f. sp. hordei at different stages of development in the host. Moreover we used a proteogenomics approach to feed information into the annotation of the newly sequenced genome. We analyzed and compared the proteomes from three stages of development representing different functions during the plant-dependent vegetative life cycle of this fungus. We identified 441 proteins in ungerminated spores, 775 proteins in epiphytic sporulating hyphae, and 47 proteins from haustoria inside barley leaf epidermal cells and used the data to aid annotation of the B. graminis f. sp. hordei genome. We also compared the differences in the protein complement of these key stages. Although confirming some of the previously reported findings and models derived from the analysis of transcriptome dynamics, our results also suggest that the intracellular haustoria are subject to stress possibly as a result of the plant defense strategy, including the production of reactive oxygen species. In addition, a number of small haustorial proteins with a predicted N-terminal signal peptide for secretion were identified in infected tissues: these represent candidate effector proteins that may play a role in controlling host metabolism and immunity. Molecular & Cellular Proteomics 8: 2368-2381, 2009.

Mothers' attributions following their child's diagnosis of autistic spectrum disorder: exploring links with maternal levels of stress, depression and expectations about their child's future

Although the impact of autism spectrum disorders (ASDs) on the family is well recognized, the way mothers attempt to make sense of the diagnosis is largely unexplored. However, in other disabilities, attributions have been shown to predict a variety of outcomes including maternal wellbeing and engagement in treatment. Using Weiner's (198S) three-dimensional model, 16 mothers were interviewed to examine the nature and impact of their beliefs about their child's ASD using semi-structured interviews and measures of depression, parenting stress and expectations for their child's future. The findings suggested that mothers made a diverse and complex range of attributions that were consistent with Weiner's dimensions of locus of cause, stability and controllability. The nature of their attributions reflected particular difficulties associated with ASDs, such as uncertainties regarding cause and prognosis. Taking account of mothers' search for meaning will better enable professionals to support families following diagnosis.

A stress relaxation model for the viscoelastic solids based on the steady-state creep equation

Creep and stress relaxation are inherent mechanical behaviors of viscoelastic materials. It is considered that both are different performances of one identical physical phenomenon. The relationship between the decay stress and time during stress relaxation has been derived from the power law equation of the steady-state creep. The model was used to analyse the stress relaxation curves of various different viscoelastic materials (such as pure polycrystalline ice, polymers, foods, bones, metal, animal tissues, etc.). The calculated results using the theoretical model agree with the experimental data very well. Here we show that the new mathematical formula is not only simple but its parameters have the clear physical meanings. It is suitable to materials with a very broad scope and has a strong predictive ability.

Assessment of the anthelmintic activity of medicinal plant extracts and purified condensed tannins against free-living and parasitic stages of Oesophagostomum dentatum

Background: Plant-derived condensed tannins (CT) show promise as a complementary option to treat gastrointestinal helminth infections, thus reducing reliance on synthetic anthelmintic drugs. Most studies on the anthelmintic effects of CT have been conducted on parasites of ruminant livestock. Oesophagostomum dentatum is an economically important parasite of pigs, as well as serving as a useful laboratory model of helminth parasites due to the ability to culture it in vitro for long periods through several life-cycle stages. Here, we investigated the anthelmintic effects of CT on multiple life-cycles stages of O. dentatum. Methods: Extracts and purified fractions were prepared from five plants containing CT and analysed by HPLC-MS. Anthelmintic activity was assessed at five different stages of the O. dentatum life cycle; the development of eggs to infective third-stage larvae (L3), the parasitic L3 stage, the moult from L3 to fourth-stage larvae (L4), the L4 stage and the adult stage. Results: Free-living larvae of O. dentatum were highly susceptible to all five plant extracts. In contrast, only two of the five extracts had activity against L3, as evidenced by migration inhibition assays, whilst three of the five extracts inhibited the moulting of L3 to L4. All five extracts reduced the motility of L4, and the motility of adult worms exposed to a CT-rich extract derived from hazelnut skins was strongly inhibited, with electron microscopy demonstrating direct damage to the worm cuticle and hypodermis. Purified CT fractions retained anthelmintic activity, and depletion of CT from extracts by pre-incubation in polyvinylpolypyrrolidone removed anthelmintic effects, strongly suggesting CT as the active molecules. Conclusions: These results suggest that CT may have promise as an alternative parasite control option for O. dentatum in pigs, particularly against adult stages. Moreover, our results demonstrate a varied susceptibility of different life-cycle stages of the same parasite to CT, which may offer an insight into the anthelmintic mechanisms of these commonly found plant compounds.