Photoautotrophs and macroinvertebrate trophic relations in calcareous semiarid streams: The role of Cyanobacteria.

Photoautotrophs and macroinvertebrate trophic relations in Mediterranean streams, especially from semiarid areas, are still poorly known, as is the role of Cyanobacteria, which is the most frequently dominant photoautotroph. To investigate the role of Cyanobacteria as a food resource in these systems, the fatty acid composition of primary and secondary producers was investigated in two streams on a semiarid climatic gradient between 200 and 500 mm of rainfall in SE Spain. Fatty acid composition of photoautotrophs and macroinvertebrates differed among streams in summer and among seasons in each stream. Fatty acid fingerprints show that macroinvertebrates usually fed on the dominant photoautotroph assemblage and that Cyanobacteria represent the main food for all the feeding groups in the Alhárabe stream in winter although filamentous green algae were preferred in summer. Only scrapers consuming Chlorophyta displayed a selective feeding behaviour. The results show the importance of cyanobacteria as food for all collected macroinvertebrates in winter in some semiarid streams and confirm that fatty acids can be used as temporal and spatial markers in fluvial systems.

Influence of aquaculture waste on fatty acid profiles and gonad maturation of wild fish aggregations at fish farms.

Wild fish belonging to four species belonging to different trophic groups were captured at three distances from fish farm facilities: long distance (>5 Km), medium distance (1.5 Km) and close to sea-cages. Flesh, brain, liver and gonads were sampled for fatty acid analysis. Fish aggregated near sea-cages showed accumulation of fatty acids of vegetable origin in the studied tissues, due to surplus feed consumption or via predation of fish that consumed the feed. Gonads accumulated vegetable fatty acids in different manner in the different species, and the species least and most influenced by fish-feeds were selected for gonad histological examination. Results showed an acceleration of the final stages of the oocyte development in fish aggregated near fish farms compared to fish captured at long distance. Differences in oocyte development were more acute in the species which incorporated higher quantities of vegetable fatty acids.

The short-term effects of farmed fish food consumed by wild fish congregating outside the farms.

We simulated in the laboratory the possible effects on fatty acids and immune status of wild fish arriving for the first time in the vicinity of a sea-cage fish farm, shifting their natural diet to commercial feed consumption, rich in fatty acids of vegetable origin. The flesh fatty acid profile of golden mullet specimens was altered after 2weeks of commercial feed consumption, showing an increase in fatty acids of vegetable origin. The serum peroxidase and bactericidal activities, and head-kidney leucocyte phagocytic capacity, increased after eight weeks of the new diet, while the respiratory burst activity decreased. The extent of these changes cannot be considered large enough to regard them as compromising the health status of fish. More research is needed in order to elucidate whether the rapid assimilation of the dietary fatty acids could harm the immune status of fish when feeding for longer periods than two months.

Mediterranean fouling communities assimilate the organic matter derived from coastal fish farms as a new trophic resource.

Currently, the lipid content of fish feeds includes high amounts of terrestrial vegetable oils, rich in n-6 fatty acids and poor in n-3 fatty acids. Sinking organic matter in the shape of fragmented pellets and fish faeces could be ingested by the surrounding fauna attracted to the submerged structures of aquaculture facilities or living in natural benthic habitats. Fatty acids contained in feed pellets were used as trophic markers to shed light on the assimilation and incorporation of aquaculture wastes by the invertebrate fauna associated to sea-cages. Eighteen macroinvertebrate species, and zooplankton, seaweeds and sediments were collected from two fish farms, one of which (control) had not been used as such for two years. This study demonstrates that macroinvertebrate fauna present in fouling can take up sinking organic matter from farms. Further research should be directed at assessing the potential implications of aquaculture production for the surrounding ecosystem.

Trophic ecology of the sea urchin Spatangus purpureus elucidated from gonad fatty acids composition analysis.

Irregular sea urchins such as the spatangoid Spatangus purpureus are important bioturbators that contribute to natural biogenic disturbance and the functioning of biogeochemical cycles in soft sediments. In the coastal waters of the Balearic Islands S. purpureus occurs in soft red algal beds, and can reach high densities. The diet of S. purpureus is unknown and it is particularly difficult to analyze the stomach contents of this group; therefore, we analyzed the fatty acid (FA) composition of the gonads and potential food resources in order to assess the trophic relationships of this species. The FA profiles of the gonads of S. purpureus agree well with the FA composition of the potential trophic resources (algae and sediment) and reveals changes between localities with different available resources. Three polyunsaturated FAs mainly contributes in the composition in the S. purpureus gonads: eicosapentaenoic acid (C20:5n-3) and arachidonic acid (C20:4n-6), both abundant in the macroalgal material, and palmitoleic acid (C16:1n-7), which is characteristic of sediment samples. Trophic markers of bacterial input and carnivorous feeding were significantly more abundant in sea urchins caught on bottoms with less vegetation. The current study demonstrates that the FA content of S. purpureus gonads is a useful marker of diet, as differences in the profiles reflected the variations in detritus composition. The results of this study show that this species has omnivorous feeding behavior; however, viewed in conjunction with available abundance data the results suggest that phytodetritus found within algal beds is an important carbon source for this species.

Seasonal eating patterns in Norway: a non-clinical population study.

Seasonal deviations in normal eating habits have been associated with seasonal affective disorder (SAD) and bulimia nervosa (BN). Two studies on seasonal variation in eating habits are reported in this paper. In Study 1, seasonal patterns of eating disturbances were measured cross-sectionally in 6313 participants using an eating disturbance scale (EDS-5) and a modified version of the Seasonal Pattern Assessment Questionnaire (SPAQ). Eating disturbance scores were predicted by seasonal sensitivity scores from the SPAQ, gender, age, and light. Study 2 used a longitudinal design in which 908 participants were given the EDS-5 every month from November 1993 to January 1995. Scores on the EDS-5 fluctuated with the season of the year, with higher EDS-5 scores in winter and lower in summer. The results suggest that seasonal fluctuations affect only a subset of the total population.

The Tromsø Social Intelligence Scale, a self-report measure of social intelligence.

Social intelligence is a construct that not only appeals to laymen as a relevant individual difference but also has shown promising practical applications. Nevertheless, the use of social intelligence in research and applied settings has been limited by definitional problems, difficulties in empirically differentiating social intelligence from related constructs, and the complexity of most existing measures of social intelligence. The goal of the present research was to address some of these obstacles by designing a multi-faceted social intelligence measure that is short and easy to administer. Three studies were conducted to develop and validate the Tromsø Social Intelligence Scale (TSIS). Study 1 examined professional psychologists' interpretations of social intelligence to derive a consensually agreed-upon definition of the construct. In Study 2, a large pool of social intelligence items were tested, and a 3-factor, 21-item scale was identified. In Study 3, the stability of this measure was confirmed.

A Norwegian translation of the self-liking and competence scale.

Although global self-esteem has historically been assumed to be a unidimensional construct, recent theory and research has challenged this assumption. Instead, it has been suggested that self-esteem might more fruitfully be viewed as a two-dimensional construct composed of: (a) self-liking, based on our perceptions of feedback from our social environment; and (b) self-competence, based on our internal conceptions of success and failure in performing tasks. The Self-Liking and Competence Scale (SLCS) is a self-esteem measure that has recently been developed based on this two-dimensional conceptualization of self-esteem. The purpose of the present research was to validate a Norwegian translation of the SLCS. 372 participants were given a translated version of the SLCS, and the translated scale exhibited psychometric properties similar to those of the original English version of the scale.

The association between implicit theories of personality and the attributional process.

The influence of implicit theories of personality (entity vs. incremental theorists; see Dweck, Chiu and Hong, 1995) on the stages of the Sequential Operations Model of attribution (Gilbert, Pelham, and Krull, 1988) was investigated. Two hundred eighty Norwegian participants were given a Norwegian translation of the implicit personality theories measure. Participants then read two essays, one advocating the pro-life position and the other advocating the pro-choice position on the abortion issue. The essay positions were ostensibly assigned rather than freely chosen by the author. After each essay, participants were asked to rate the essay position and the true attitude of the author. Entity and incremental theorists showed no differences in their ratings of the essay position; however, entity theorists made significantly stronger correspondent inferences about the author's attitude than did incremental theorists. These results support the contention that entity theorists engage in less attributional correction than incremental theorists.

The effects of cognitive load on strategic self-handicapping.

Past research has demonstrated that observers tend to underestimate the importance of situational determinants (e.g. task difficulty) of the performances of others. This tendency is particularly pronounced when observers are unmotivated, distracted or otherwise 'cognitively busy' while making attributional judgments. The objective of the present research was to determine whether a similar tendency exists when actors are given the opportunity to choose the tasks they will undertake in a self-presentational situation. Sixty-one participants were given a choice between a difficult and a simple task, with cognitive busyness being manipulated while this choice was being made. Cognitively busy participants were significantly more likely to choose the simple task than their non-busy counterparts.

The N-terminal K homology domain of the poly(rC)-binding protein is a major determinant for binding to the poliovirus 5'-untranslated region and acts as an inhibitor of viral translation.

The poly(rC)-binding proteins (PCBP1 and PCBP2) are RNA-binding proteins whose RNA recognition motifs are composed of three K homology (KH) domains. These proteins are involved in both the stabilization and translational regulation of several cellular and viral RNAs. PCBP1 and PCBP2 specifically interact with both the 5'-element known as the cloverleaf structure and the large stem-loop IV RNA of the poliovirus 5'-untranslated region. We have found that the first KH domain of PCBP2 (KH1) specifically interacts with the viral RNAs, and together with viral protein 3CD, KH1 forms a high affinity ternary ribonucleoprotein complex with the cloverleaf RNA, resembling the full-length PCBP protein. Furthermore, KH1 acts as a dominant-negative mutant to inhibit translation from a poliovirus reporter gene in both Xenopus laevis oocytes and HeLa cell in vitro translation extracts.

Intracellular determinants of picornavirus replication.

Viruses replicate in a restricted number of hosts and tissues. In addition to viral receptors, several intracellular factors can be involved in determining tissue tropism. Many proteins have recently been implicated in picornavirus translation and RNA replication. Although the functional role of these proteins has not been established in vivo, it is possible that they determine cell-type tropism and the pathogenic outcome of the infection.

Eating pattern and self-esteem in overweight women.

Recent studies have shown that the relationship between poor self-esteem and disturbed eating patterns may be more fully understood when the self-esteem concept is divided into an affective domain ('self-liking') and a cognitive domain ('self-competence'). In the present study 38 overweight women between the ages of 21 and 68 participated in an 8-week weight reduction program whereby the Self-Liking and Competence Scale [SLCS] and the Eating Disorder Scale [EDS-5] were used in order to measure self-esteem and eating patterns, respectively. An improvement in the eating patterns corresponded to an improvement in self-liking, but not in self-competence. Statistically significant weight reduction did occur, but on the average, the subjects still remained overweight. As in other studies on normal weight individuals in analogous test situations completing the same instruments, the results point only to a specific relationship between disturbed eating patterns and self-liking. The results suggest that an increased benefit from a weight reduction program could be expected if strategies for improving eating patterns and self-liking are included. This hypothesis warrants further controlled treatment studies.

Analyzing the relation between self-esteem and eating disorders: differential effects of self-liking and self-competence.

Research in the past has demonstrated an association between low self-esteem and eating disorders. Recent research on self-esteem has shown, however, that self-esteem is composed of two distinct factors--self-liking and self-competence. The present study examined the relation between these two self-esteem factors and both eating disorders and eating disturbed cognitions. A total of 51 female participants from a high-risk population were clinically interviewed to identify the eating disorder and administered a series of questionnaires that included a measure of self-liking and self-competence. A strong relationship was found between self-liking and eating disorders, but no relationship was found between self-competence and eating disorders.

Toward a poliovirus-based simian immunodeficiency virus vaccine: correlation between genetic stability and immunogenicity.

Recombinant polioviruses expressing foreign antigens may provide a convenient vaccine vector to engender mucosal immunity. Replication-competent chimeric viruses can be constructed by fusing foreign antigenic sequences to several positions within the poliovirus polyprotein. Artificial cleavage sites ensure appropriate proteolytic processing of the recombinant polyprotein, yielding mature and functional viral proteins. To study the effect of the position of insertion, two different recombinant polioviruses were examined. A small amino-terminus insertion delayed virus maturation and produced a thermosensitive particle. In contrast, insertion at the junction between the P1 and P2 regions yielded a chimeric poliovirus that replicated like the wild type. Eight different chimeras were constructed by inserting simian immunodeficiency virus (SIV) sequences at the P1/P2 junction. All recombinant viruses replicated with near-wild-type efficiency in tissue culture cells and expressed high levels of the SIV antigens. One of the inserted fragments corresponding to gp41 envelope protein was N-glycosylated but was not secreted. Inserted sequences were only partially retained after few rounds of replication in HeLa cells. This problem could be remedied to some extent by altering the sequences flanking the insertion point. Reducing the homology of the direct repeats by 37% decrease the propensity of the recombinant viruses to delete the insert. To determine the immunogenic potential of the recombinants, mice susceptible to poliovirus infection were inoculated intraperitoneally. The antibody titers elicited against Gag p17 depended on the viral doses and the number of inoculations. In addition, recombinants which display higher genetic stability were more effective in inducing an immune response against the SIV antigens, and inoculation with a mix of recombinants carrying different SIV antigens (a cocktail of recombinants) elicited humoral responses against each of the individual SIV sequences.

Overhelping.

Overhelping occurs when one attempts to spoil an observer's impression of a performer by explicitly helping the performer achieve a goal, thereby inviting the observer to attribute the performer's success to the help. The results of 4 experiments suggest (a) that people are most likely to overhelp when they believe that their interventions will be ineffective but will be considered effective by observers and (b) that when either of these beliefs is wrong, the strategy will backfire. The results point to an intervention principle that predicts how and when people may most effectively influence a performance so as to shape observer's inferences about the performer.

Engineering poliovirus as a vaccine vector for the expression of diverse antigens.

As a step toward developing poliovirus as a vaccine vector, poliovirus recombinants were constructed by fusing exogenous peptides (up to 400 amino acids) and an artificial cleavage site for viral protease 3Cpro to the amino terminus of the viral polyprotein. Viral replication proceeded normally. An extended polyprotein was produced in infected cells and proteolytically processed into the complete array of viral proteins plus the foreign peptide, which was excluded from mature virions. The recombinants retained exogenous sequences through successive rounds of replication in culture and in vivo. Infection of animals with recombinants elicited a humoral immune response to the foreign peptides.