Do cleaning organisms reduce the stress response of client reef fish?

Marine cleaning interactions in which cleaner fish or shrimps remove parasites from visiting 'client' reef fish are a textbook example of mutualism. However, there is yet no conclusive evidence that cleaning organisms significantly improve the health of their clients. We tested the stress response of wild caught individuals of two client species, Chromis dimidiata and Pseudanthias squamipinnis, that had either access to a cleaner wrasse Labroides dimidiatus, or to cleaner shrimps Stenopus hispidus and Periclimenes longicarpus, or no access to cleaning organisms. For both client species, we found an association between the presence of cleaner organisms and a reduction in the short term stress response of client fish to capture, transport and one hour confinement in small aquaria, as measured with cortisol levels. It is conceivable that individuals who are more easily stressed than others pay a fitness cost in the long run. Thus, our data suggest that marine cleaning mutualisms are indeed mutualistic. More generally, measures of stress responses or basal levels may provide a useful tool to assess the impact of interspecific interactions on the partner species

Free and conjugated androgen and progestin levels in the serum of stellate sturgeon (Acipenser stellatus Pallas) males treated with female coelomic fluid

Based on the supposition that female coelomic fluid contents have a certain chemical influence on sturgeons, blood serum concentrations of free and conjugated testosterone (T), 11-ketotestosterone (11KT), 17,20b,21-trihydroxy-4-pregnen- 3-one (20bS), 17,20b-dihydroxy-4-pregnen-3-one (DHP), 11-desoxycortisol (S) and free progesterone (P4) have been measured by radioimmunoassay (RIA) and enzyme-linked immuno-sorbent assay (ELISA) in stellate sturgeon (Acipenser stellatus Pallas) males treated with female coelomic fluid (CF); CF steroid levels have also been analyzed. After treatment a significant elevation of free 20bS and glucuronidated DHP and S levels and the decrease of free T and KT levels have been observed. The obtained data support the idea that the components of CF may play some part in pheromonal effects for sturgeon reproduction

Free androgens and progestins and their conjugated forms in serum and urine of stellate sturgeon (Acipenser stellatus Pallas) males

Stellate sturgeon (Acipenser stellatus Pallas) males from Volga River treated with LH-RH-A showed an increase of free, sulfated and glucuronided sex steroid levels in serum and urine at spermiation. Conjugated forms of sex steroids could act as pheromones in sturgeon

Levels of free and conjugated androgens and progestins in coelomic fluid and serum of stellate sturgeon (Acipenser stellatus Pallas) females

Stellate sturgeon (Acipenser stellatus Pallas) females from the Volga River were analysed for sex steroids after hormonal stimulation. The results show a significant increase of sulfated sex steroid levels in serum and coelomic fluid (CF) at final maturation (FM). It is hypothesized that the steroid metabolites could be part of a chemical communication system related to reproduction

Novel galanin receptors in teleost fish: identification, expression and regulation by sex steroids

In fish, the onset of puberty, the transition from juvenile to sexually reproductive adult animals, is triggered by the activation of pituitary gonadotrophin secretion and its timing is influenced by external and internal factors that include the growth/adiposity status of the animal. Kisseptins have been implicated in the activation of puberty but peripheral signals coming from the immature gonad or associated to the metabolic/nutritional status are also thought to be involved. Additionally, there is evidence that the galaninergic system in the brain and testis of pre-pubertal male sea bass is a possible mediator involved in the translation of somatic signals leading to gonadal maturation. Here, the transcripts for four galanin receptors (GALR), named GALR1a, 1b, 2a and 2b, were isolated from European sea bass, Dicentrarchus labrax. Phylogenetic analysis confirmed the previously reported duplication of GALR1 in teleost fish, and unravelled the duplication of GALR2 in teleost fish and in some tetrapod species. Comparison with human showed that the key amino acids involved in ligand binding are present in the corresponding GALR1 and GALR2 orthologues. Transcripts for all four receptors are expressed in brain and testes of adult fish with GALR1a and GALR1b abundant in testes 15 and hardly detected in ovaries. In order to investigate whether GALR1 dimorphic expression was dependent on steroid context we evaluated the effect of 11-ketotestosterone and 17β-estradiol treatments on the receptor expression in brain and testes of pre-pubertal males. Interestingly, steroid treatments had no effect on the expression of GALRs in the brain while in the testes, GALR1a and GALR1b were significantly up regulated by 11KT. Altogether, these results support a role for the galaninergic system, in particular the GALR1 paralog in fish reproductive function

Downhill Running-based Overtraining Protocol Improves Hepatic Insulin Signaling Pathway Without Concomitant Decrease Of Inflammatory Proteins

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The purpose of this study was to verify the effects of overtraining (OT) on insulin, inflammatory and gluconeogenesis signaling pathways in the livers of mice. Rodents were divided into control (CT), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up) and overtrained by running without inclination (OTR). Rotarod, incremental load, exhaustive and grip force tests were used to evaluate performance. Thirty-six hours after a grip force test, the livers were extracted for subsequent protein analyses. The phosphorylation of insulin receptor beta (pIRbeta), glycogen synthase kinase 3 beta (pGSK3beta) and forkhead box O1 (pFoxo1) increased in OTR/down versus CT. pGSK3beta was higher in OTR/up versus CT, and pFoxo1 was higher in OTR/up and OTR versus CT. Phosphorylation of protein kinase B (pAkt) and insulin receptor substrate 1 (pIRS-1) were higher in OTR/up versus CT and OTR/down. The phosphorylation of I kappa B kinase alpha and beta (pIK-Kalpha/beta) was higher in all OT protocols versus CT, and the phosphorylation of stress-activated protein kinases/Jun amino-terminal kinases (pSAPK-JNK) was higher in OTR/ down versus CT. Protein levels of peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha) and hepatocyte nuclear factor 4alpha (HNF-4alpha) were higher in OTR versus CT. In summary, OTR/down improved the major proteins of insulin signaling pathway but up-regulated TRB3, an Akt inhibitor, and its association with Akt.1010Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2013/20591-3, 2014/25459-9, 2013/22737-5, 2013/19985-7

Development and validation of a gene expression oligo microarray for the gilthead sea bream (Sparus aurata)

Aquaculture represents the most sustainable alternative of seafood supply to substitute for the declining marine fisheries, but severe production bottlenecks remain to be solved. The application of genomic technologies offers much promise to rapidly increase our knowledge on biological processes in farmed species and overcome such bottlenecks. Here we present an integrated platform for mRNA expression profiling in the gilthead sea bream (Sparus aurata), a marine teleost of great importance for aquaculture

Developmental expression of DAXI in the European sea bass, Dicentrarchus labrax: lack of evidence for sexual dimorphism during sex differentiation

Background: DAX1 (NR0B1), a member of the nuclear receptors super family, has been shown to be involved in the genetic sex determination and in gonadal differentiation in several vertebrate species. In the aquaculture fish European sea bass, Dicentrarchus labrax, and in the generality of fish species, the mechanisms of sex determination and differentiation have not been elucidated. The present study aimed at characterizing the European DAX1 gene and its developmental expression at the mRNA level. Methods: A full length European sea bass DAX1 cDNA (sbDAX1) was isolated by screening a testis cDNA library. The structure of the DAX1 gene was determined by PCR and Southern blot. Multisequence alignments and phylogenetic analysis were used to compare the translated sbDAX1 product to that of other vertebrates. sbDAX1 expression was analysed by Northern blot and relative RT-PCR in adult tissues. Developmental expression of mRNA levels was analysed in groups of larvae grown either at 15°C or 20°C (masculinising temperature) during the first 60 days, or two groups of fish selected for fast (mostly females) and slow growth. Results: The sbDAX1 is expressed as a single transcript in testis and ovary encoding a predicted protein of 301 amino acids. A polyglutamine stretch of variable length in different DAX1 proteins is present in the DNA binding domain. The sbDAX1 gene is composed of two exons, separated by a single 283 bp intron with conserved splice sites in same region of the ligand binding domain as other DAX1 genes. sbDAX1 mRNA is not restricted to the brain-pituitary-gonadal axis and is also detected in the gut, heart, gills, muscle and kidney. sbDAX1 mRNA was detected as early as 4 days post hatching (dph) and expression was not affected by incubation temperature. Throughout gonadal sex differentiation (60–300 dph) no dimorphic pattern of expression was observed. Conclusion: The sbDAX1 gene and putative protein coding region is highly conserved and has a wide pattern of tissue expression. Although gene expression data suggests sbDAX1 to be important for the development and differentiation of the gonads, it is apparently not sex specific

Outdoor play as a mean to achieve educational goals: a case study in a Portuguese day-care group

This study aims to explore the pedagogical potential of outdoor play situations, considering the educational goals established in the Portuguese Pedagogical Guidelines for 0–3-year-old children (ongoing work), namely development of a sense of security and positive selfesteem; development of curiosity and exploratory impetus; and development of social and communication skills. Following a qualitative methodology, during a period of 9 months, the outdoor play experiences of 14 children from a day-care centre were observed and monitored and the professionals were interviewed. The data shows that outdoor experiences can contribute to the achievement of the educational goals, enlarging opportunities for creative play, problem solving, experimentation, inquiry, dialogues and collaboration. The achievement of the educational goals is facilitated through supportive and positive relationships with adults and peers, provision for proper equipment, and contact with nature. This study offers a deep insight into how educational policies can be put into practice in the outdoor area.publishe