Teknikundervisning i grundskolan : En systematisk litteraturstudie om hur undervisningen kan utformas så att eleverna utvecklar förmågor i ämnet teknik

Syftet med denna studie var att se vad tidigare forskning säger om på vilka sätt elever kan utveckla förmågorna att analysera och reflektera kring tekniska lösningar samt se behov och lösa problem med hjälp av teknik, som anges i kursplanen för ämnet teknik i grundskolan. För att besvara dessa frågeställningar har en systematisk litteraturstudie gjorts där tidigare forskning har använts för att sammanställa ett resultat. Sökningar har gjorts i databaserna Summon, Eric (via Ebsco) och NorDiNa och relevanta artiklar har valts ut, sammanställts och diskuterats. I studien framkommer ett antal faktorer som är viktiga för elevernas utveckling av förmågorna. En faktor som framkommit i denna studie är behovet av diskussioner där eleverna får möjlighet att delge sina reflektioner kopplat till tekniska lösningar och ta till sig andras reflektioner, vilket har visat sig vara viktig för elevernas analysförmåga. En annan faktor är att eleverna behöver tid att testa och konstruera om för att utveckla sina idéer samt ges möjlighet att koppla tekniken till sin vardag. Det har också visat sig vara viktigt att problemlösningsuppgifterna inte är styrda att leda till ett specifikt resultat utan istället handlar om att träna elevernas förmåga att upptäcka olika lösningsförslag.

Gymaktivas inställning till sin egen träning i förhållande till olika motivationsfaktorer

Studiens syfte var att undersöka gymaktiva kvinnors motivationsfaktorer och om dessa kan vara mer eller mindre positiv för enskilda individer. De motivationsfaktorer studien inriktade sig på är tre olika kroppsideal, det utseendemässiga kroppsidealet, funktionella kroppsidealet eller hälsomässiga kroppsidealet, som tidigare forskning beskrivit är dessa vanliga anledningar till att personer tränar. Metoden i studien är en kvalitativ innehållsanalys baserad på individuella intervjuer av 9 kvinnor i åldrarna 20-30. Studiens resultat visade på att de främsta motivationsfaktorerna var att träna för hälsan eller för utseendet. Endast en respondent visade sig träna för att få en funktionellt bättre fungerande kropp. Vidare framkom att alla motivationsfaktorerna hade positiv inverkan på måendet, dock visade det sig också att de som tränade för det utseendemässiga kroppsidealet kände en del negativa aspekter som t.ex. mer press än vad de som tränade för det hälsomässiga kroppsidealet gjorde. Samtliga respondenter kände att motivationen gick i perioder vilket tyder på att motivationsfaktorn inte verkar ha en inverkan på motivationsgraden

Läsförmåga och matematiska resonemang : Relationen mellan läsförmåga och resonemangsförmåga

Ett starkt samband mellan elevers läsförmåga och deras prestationer i matematik har konstaterats i tidigare forskning. Syftet med detta examensarbete är att, utifrån aktuell forskning, undersöka om och i så fall hur läsförmåga och förmågan att föra matematiska resonemang samverkar när elever i årskurs 4-6 löser matematiska problem och uppgifter som beskrivs i skriven text. Ur syftet preciseras frågeställningen: På vilket sätt är läsförmåga och matematisk resonemangsförmåga kopplade till varandra? Syfte och frågeställning har undersökts i form av en systematisk litteraturstudie som inneburit att vetenskaplig forskning har sökts, granskats och analyserats. Den litteratur som uppfyllt på förhand ställda krav och därmed valts att ingå i studien har analyserats med hjälp av en innehållsanalys. Resultatet av litteraturstudien varken bekräftar eller avfärdar att en överlappning mellan läsförmåga och resonemangsförmåga skulle existera. Däremot pekar flera av studierna på att ett samspel mellan dessa skilda förmågor finns och är aktivt vid elevers arbete med matematiska textuppgifter. Ur resultatet tolkas några möjliga konsekvenser för undervisningen i grundskolans årskurs 4-6 fram: Undervisning som omfattar matematiska uppgifter och problem bör planeras ur såväl språkligt som matematiskt perspektiv. Eleverna bör ges rikliga möjligheter att träna såväl förmågan att läsa och tolka uppgiftstexter som den matematiska resonemangsförmågan. Detta sker lämpligen i arbetsformer där eleverna ges möjlighet till social interaktion.

Saccharomycotin transcriptomics by next-generation sequencing

The non-standard decoding of the CUG codon in Candida cylindracea raises a number of questions about the evolutionary process of this organism and other species Candida clade for which the codon is ambiguous. In order to find some answers we studied the transcriptome of C. cylindracea, comparing its behavior with that of Saccharomyces cerevisiae (standard decoder) and Candida albicans (ambiguous decoder). The transcriptome characterization was performed using RNA-seq. This approach has several advantages over microarrays and its application is booming. TopHat and Cufflinks were the software used to build the protocol that allowed for gene quantification. About 95% of the reads were mapped on the genome. 3693 genes were analyzed, of which 1338 had a non-standard start codon (TTG/CTG) and the percentage of expressed genes was 99.4%. Most genes have intermediate levels of expression, some have little or no expression and a minority is highly expressed. The distribution profile of the CUG between the three species is different, but it can be significantly associated to gene expression levels: genes with fewer CUGs are the most highly expressed. However, CUG content is not related to the conservation level: more and less conserved genes have, on average, an equal number of CUGs. The most conserved genes are the most expressed. The lipase genes corroborate the results obtained for most genes of C. cylindracea since they are very rich in CUGs and nothing conserved. The reduced amount of CUG codons that was observed in highly expressed genes may be due, possibly, to an insufficient number of tRNA genes to cope with more CUGs without compromising translational efficiency. From the enrichment analysis, it was confirmed that the most conserved genes are associated with basic functions such as translation, pathogenesis and metabolism. From this set, genes with more or less CUGs seem to have different functions. The key issues on the evolutionary phenomenon remain unclear. However, the results are consistent with previous observations and shows a variety of conclusions that in future analyzes should be taken into consideration, since it was the first time that such a study was conducted.

”Det är som fyra, fyra och tre, tre, tre.”: En kvalitativ studie av små gruppers diskussioner och samarbete vid lösandet av ett matematiskt problem i tre olika länder i årskurs 6.

Avhandlingens syfte är att undersöka lösningsförslags uppkomst och behandling i små grupparbeten samt att ta reda på samband mellan samarbetsnivån och behandlingen av dessa lösningsförslag. Mina problemformuleringar är: - Hur många lösningsförslag uppstår i grupperna, och hur mycket behandlas de? - Existerar, och i så fall vad kan man säga om, ett samband mellan samarbetsnivån och behandlingen av dessa lösningsförslag? I studien har en kvalitativ metod använts. Insamling av material har gjorts via VIDEOMATprojektet och består av videofilmer av problemlösningstillfällen. Dessa filmer har observerats och analyserats med hjälp av en interaktionsanalys i form av ett flödesschema. Alla elever i studien gick vid tillfället i årskurs 6 och eleverna kommer från Finland, Sverige och USA. Grupperna bestod av tre eller fyra elever var och en grupp från varje land observerades och undersöktes. Inga generella slutsatser beträffande ländernas olika prestationer har gjorts eftersom samplet är litet. I varje grupp uppstod tre eller fyra olika lösningsförslag, och huvudsakligen behandlades två av förslagen mer än de andra. De flesta lösningsförslag som inte behandlades mycket bidrog ändå i någon form till lösandet av problemet. Angående sambandet mellan behandlingen av lösningsförslagen och samarbetsnivån i grupperna blev det tydligt att grupper som samarbetar mer använde sig av fler pro- och reaktiva kommentarer i form av förklaringar som tog i beaktande det som tidigare sagts av eleverna. Goda sociala färdigheter, och kunskap om hur man arbetar i grupp, är essentiella både för samarbetet och för ett gemensamt lösande av problemet. Som lärare kan man träna eleverna i samarbete och belysa vikten av reflektion av de erhållna lösningarna i problemlösningsprocessernas slutskede för att uppnå effektivare grupparbeten. Interaktionsanalysen visade sig vara ett kraftigt verktyg för att analysera elevernas diskussioner och tolka deras kommentarer.

Potencial fisiológico de sementes de soja enriquecidas com molibdênio no armazenamento e sua influência na atividade de enzimas do metabolismo do nitrogênio

Molybdenum is one of the essential micronutrients for soybeans, acting directly on nitrogen metabolism as enzyme cofactor of nitrogenase. Usually, this nutrient is supplied to the plants through seed treatment or foliar application. The aim of this study was to evaluate the molybdenum effects by foliar in the physiological potential of soybean seeds and verify its interference in the enzyme activities involved in nitrogen metabolism. Soybean seeds of BMX Turbo cultivar were used, produced in Erechim, RS, harvest 2013, from plants treated with the following Mo concentrations: 0; 25; 50 and 75 g ha-1, supplied through two commercial products (Biomol and Molybdate) and stored during 0 and 6 months in uncontrolled conditions. The first experiment was conducted in Seedtes Seed Analysis Laboratory in Pato Branco, PR. The used design was completely randomized in a factorial analysis 4 x 2 x 2 with four replications each. The physiological potential of the seeds was evaluated by the germination test, seedling growth, accelerated aging and emergence on the soil. The second experiment was conducted in a greenhouse, where the seeds derived from treatments with different concentrations of Mo: 0; 25; 50 and 75 g ha-1 supplied through two commercial products (Biomol and Molybdate) were grown in vases. The used design was completely randomized in a factorial analysis 4 x 2 with four replications. Evaluations were performed when the plants reached the R1 phenological stage concerning the nodulation, dry matter of root and shoot of the plants and the determination of the activity of the enzymes glutamine synthetase and glutamate synthetase and the content of total soluble proteins. The data were submitted to variance analysis and when significant they were assessed by Tukey’s test for comparison of products and seed storage and with regression study to the concentrations at 5% probability. Analyses were performed using SISVAR statistical software. The soybean seed storage under uncontrolled conditions affected the seed vigour produced with Mo, regardless of the commercial product used during production. The application of Mo through foliar positively influences the production of soya beans which presented increasing responses in the germination and vigour with the application of Mo above 25 g ha-1 . The enrichment of Mo through foliar did not affect the nodulation of plants of the next generation, however, the use of Mo above 25 g ha-1 provided an increase in the activity of enzymes involved in nitrogen metabolism as well as on the total protein content.

STRUCTURAL ANALYSIS OF RIBOSOME BINDING ELEMENTS OF THE 3´ UTR IN TWO POSITIVE-STRAND PLANT RNA VIRUSES

Turnip crinkle virus (TCV) and Pea enation mosaic virus (PEMV) are two positive (+)-strand RNA viruses that are used to investigate the regulation of translation and replication due to their small size and simple genomes. Both viruses contain cap-independent translation elements (CITEs) within their 3´ untranslated regions (UTRs) that fold into tRNA-shaped structures (TSS) according to nuclear magnetic resonance and small angle x-ray scattering analysis (TCV) and computational prediction (PEMV). Specifically, the TCV TSS can directly associate with ribosomes and participates in RNA-dependent RNA polymerase (RdRp) binding. The PEMV kissing-loop TSS (kl-TSS) can simultaneously bind to ribosomes and associate with the 5´ UTR of the viral genome. Mutational analysis and chemical structure probing methods provide great insight into the function and secondary structure of the two 3´ CITEs. However, lack of 3-D structural information has limited our understanding of their functional dynamics. Here, I report the folding dynamics for the TCV TSS using optical tweezers (OT), a single molecule technique. My study of the unfolding/folding pathways for the TCV TSS has provided an unexpected unfolding pathway, confirmed the presence of Ψ3 and hairpin elements, and suggested an interconnection between the hairpins and pseudoknots. In addition, this study has demonstrated the importance of the adjacent upstream adenylate-rich sequence for the formation of H4a/Ψ3 along with the contribution of magnesium to the stability of the TCV TSS. In my second project, I report on the structural analysis of the PEMV kl-TSS using NMR and SAXS. This study has re-confirmed the base-pair pattern for the PEMV kl-TSS and the proposed interaction of the PEMV kl-TSS with its interacting partner, hairpin 5H2. The molecular envelope of the kl-TSS built from SAXS analysis suggests the kl-TSS has two functional conformations, one of which has a different shape from the previously predicted tRNA-shaped form. Along with applying biophysical methods to study the structural folding dynamics of RNAs, I have also developed a technique that improves the production of large quantities of recombinant RNAs in vivo for NMR study. In this project, I report using the wild-type and mutant E.coli strains to produce cost-effective, site-specific labeled, recombinant RNAs. This technique was validated with four representative RNAs of different sizes and complexity to produce milligram amounts of RNAs. The benefit of using site-specific labeled RNAs made from E.coli was demonstrated with several NMR techniques.

Population genetic structure of Neogobius caspius (Eichwald ,1831) in the South Caspian Sea using PCR-RFLP Marker

Neogobius caspius is a small benthic fish that is native to the Caspian Sea. The importance of this fish is because of it is role as a main food resource of the sturgeon fish. The genetic diversity of N. caspius population in the Caspian Sea was studied using PCR- RFLP technique. A total of 135 samples of N. caspius were collected from coastal line in the north Caspian sea, including specimens from coasts of Anzali , Torkman Port and Chalus. Genomic DNA was extracted by phenol-chloroform method and then was amplified using a pair primer of cytochrom b gene, 2 tRNA gene and the control region sequences by a thermal cycler. D2 (5'-CCGGAGTATGTAGGGCATTCTCAC-3'), CY1 (5'-YYTAACCRRGACYAATGACTTGA-3') 12 restriction enzyme were used to digest the target gene region including: Alul HincII —Tas1 —Rsa1 -MboI -DraI -BSeNI(BSRI) Alw261(BsmAI). Bsul 51 Hin11 Bsh12851- BsuRI(HaeIII) digested PCR products were observed by silver staining method followed by Polyacrylamide gel electrophoresis (PAGE). The results were shown the same pattern among the species. There was no polymorphism and no differentiation in population in the Neogobius caspius fish and all individuals have shown homogenous genotype.

Proteomic and phosphoproteomic analysis of polyethylene glycol-induced osmotic stress in root tips of common bean (Phaseolus vulgaris L.)

Previous studies have shown that polyethylene glycol (PEG)-induced osmotic stress (OS) reduces cell-wall (CW) porosity and limits aluminium (Al) uptake by root tips of common bean (Phaseolus vulgaris L.). A subsequent transcriptomic study suggested that genes related to CW processes are involved in adjustment to OS. In this study, a proteomic and phosphoproteomic approach was applied to identify OS-induced protein regulation to further improve our understanding of how OS affects Al accumulation. Analysis of total soluble proteins in root tips indicated that, in total, 22 proteins were differentially regulated by OS; these proteins were functionally categorized. Seventy-seven per- cent of the total expressed proteins were involved in metabolic pathways, particularly of carbohydrate and amino acid metabolism. An analysis of the apoplastic proteome revealed that OS reduced the level of five proteins and increased that of seven proteins. Investigation of the total soluble phosphoproteome suggested that dehydrin responded to OS with an enhanced phosphorylation state without a change in abundance. A cellular immunolocalization analysis indicated that dehydrin was localized mainly in the CW. This suggests that dehydrin may play a major protective role in the OS-induced physical breakdown of the CW structure and thus maintenance of the reversibility of CW extensibility during recovery from OS. The proteomic and phosphoproteomic analyses provided novel insights into the complex mechanisms of OS-induced reduction of Al accumulation in the root tips of common bean and highlight a key role for modification of CW structure.

Near complete genome sequence of the animal feed probiotic, Bacillus amyloliquefaciens H57

Bacillus amyloliquefaciens H57 is a bacterium isolated from lucerne for its ability to prevent feed spoilage. Further interest developed when ruminants fed with H57-inoculated hay showed increased weight gain and nitrogen retention relative to controls, suggesting a probiotic effect. The near complete genome of H57 is ~3.96 Mb comprising 16 contigs. Within the genome there are 3,836 protein coding genes, an estimated sixteen rRNA genes and 69 tRNA genes. H57 has the potential to synthesise four different lipopeptides and four polyketide compounds, which are known antimicrobials. This antimicrobial capacity may facilitate the observed probiotic effect.

Biosynthesis and mode of action of ribosomally synthesized and post-translationally modified antimicrobial peptides

One of the greatest sources of biologically active compounds is natural products. Often these compounds serve as platforms for the design and development of novel drugs and therapeutics. The overwhelming amount of genomic information acquired in recent years has revealed that ribosomally synthesized and post-translationally modified natural products are much more widespread than originally anticipated. Identified in nearly all forms of life, these natural products display incredible structural diversity and possess a wide range of biological functions that include antimicrobial, antiviral, anti-inflammatory, antitumor, and antiallodynic activities. The unique pathways taken to biosynthesize these compounds offer exciting opportunities for the bioengineering of these complex molecules. The studies described herein focus on both the mode of action and biosynthesis of antimicrobial peptides. In Chapter 2, it is demonstrated that haloduracin, a recently discovered two-peptide lantibiotic, possesses nanomolar antimicrobial activity against a panel of bacteria strains. The potency of haloduracin rivals that of nisin, an economically and therapeutically relevant lantibiotic, which can be attributed to a similar dual mode of action. Moreover, it was demonstrated that this lantibiotic of alkaliphile origin has better stability at physiological pH than nisin. The molecular target of haloduracin was identified as the cell wall peptidoglycan precursor lipid II. Through the in vitro biosynthesis of haloduracin, several analogues of Halα were prepared and evaluated for their ability to inhibit peptidoglycan biosynthesis as well as bacterial cell growth. In an effort to overcome the limitations of in vitro biosynthesis strategies, a novel strategy was developed resulting in a constitutively active lantibiotic synthetase enzyme. This methodology, described in Chapter 3, enabled the production of fully-modified lacticin 481 products with proteinogenic and non-proteinogenic amino acid substitutions. A number of lacticin 481 analogues were prepared and their antimicrobial activity and ability to bind lipid II was assessed. Moreover, site-directed mutagenesis of the constitutively active synthetase resulted in a kinase-like enzyme with the ability to phosphorylate a number of peptide substrates. The hunt for a lantibiotic synthetase enzyme responsible for installing the presumed dehydro amino acids and a thioether ring in the natural product sublancin, led to the identification and characterization of a unique post-translational modification. The studies described in Chapter 4, demonstrate that sublancin is not a lantibiotic, but rather an unusual S-linked glycopeptide. Its structure was revised based on extensive chemical, biochemical, and spectroscopic characterization. In addition to structural investigation, bioinformatic analysis of the sublancin gene cluster led to the identification of an S-glycosyltransferase predicted to be responsible for the post-translational modification of the sublancin precursor peptide. The unprecedented glycosyltransferase was reconstituted in vitro and demonstrated remarkable substrate promiscuity for both the NDP-sugar co-substrate as well as the precursor peptide itself. An in vitro method was developed for the production of sublancin and analogues which were subsequently evaluated in bioactivity assays. Finally, a number of putative biosynthetic gene clusters were identified that appear to harbor the necessary genes for production of an S-glycopeptide. An additional S-glycosyltransferase with more favorable intrinsic properties including better expression, stability, and solubility was reconstituted in vitro and demonstrated robust catalytic abilities.

MECHANISM OF UPREGULATION OF PHOSPHATIDYLCHOLINE SYNTHESIS DURING PICORNAVIRUS INFECTION AND ITS ROLE IN THE DEVELOPMENT OF VIRAL REPLICATION ORGANELLES

Picornaviruses are a group of human and animal pathogens capable of inflicting serious public health diseases and economic burdens. Treatments options through vaccines for prevention or antivirals to cure infection are not available for the vast majority of these viruses. These shortcomings, in the development of vaccines or antivirals therapeutic, are linked to the genetic diversity and to an incomplete understanding of the biology of these viruses. Despite the diverse host range, this group of positive-strand RNA viruses shares the same replication mechanisms, including the development of membranous structures (replication organelles) in the cytoplasm of infected cells. The development of these membranous structures, which serve as sites for the replication of the viral RNA genome, has been linked to the hijacking of elements of the cellular membrane metabolism pathways. Here we show that upon picornavirus infection, there is a specific activation of acyl-CoA synthetase enzymes resulting in strong import and accumulation of long chain fatty acids in the cytoplasm of infected cells. We show that the newly imported fatty acids serve as a substrate for the upregulation of phosphatidylcholine synthesis required for the structural development of replication organelles. In this work, we identified that acyl-CoA synthetase long chain 3 (ACSL3) is required for the upregulation of lipids syntheses and the replication of poliovirus. We have shown that the poliovirus protein 2A was required but not sufficient for the activation of import of long chain fatty acids in infected cells. We demonstrated that the fatty acid import is upregulated upon infection by diverse picornaviruses and that such upregulation is not dependent on activation of ER stress response or the autophagy pathways. In this work, we have demonstrated that phosphatidylcholine was required for the structural development of replication organelles. Phosphatidylcholine synthesis was dispensable for the production of infectious particles at high MOI but required at a low MOI for the protection of the replication complexes from the cellular innate immunity mechanisms.

Genes found in partial sequencing od Phytophthora cinnamomi

Members of the oomycete cause extensive losses in agriculture and widespread degradation in natural plant communities, being responsible for the death of thousands of trees every year. Two of the representative species are Phytophthora infestans, which causes late blight of potato, and Phytophthora cinnamomi, which causes chestnut ink disease, responsible for losses on sweet chestnut production in Europe. Genome sequencing efforts have been focused on the study of three species: P. infestans, P. sojae and P. ramorum. Phytophthora infestans has been developed as the model specie for the genus, possessing excellent genetic and genomics resources including genetic maps, BAC libraries, and EST sequences. Our research team is trying to sequence the genome of P. cinnamomi in order to gain a better understanding of this oomycete, to study changes in plant-pathogen relationships including those resulting from climate change and trying to decrease the pathogen’s impact on crops and plants in natural ecosystems worldwide. We present here a preliminary report of partially sequenced genomic DNA from P. cinnamomi encoding putative protein-coding sequences and tRNAs. Database analysis reveals the presence of genes conserved in oomycetes.

Potential protective role of reactive astrocytes in the periventricular parenchyma in congenital hydrocephalus

Background Cerebrospinal fluid accumulation in hydrocephalus produces an elevation of intraventricular pressure with pathological consequences on the periventricular brain parenchyma including ischemia, oedema, oxidative stress, and accumulation of metabolic waste products. Here we studied in the hyh mouse, an animal model of congenital hydrocephalus, the role of reactive astrocytes in this clinical degenerative condition. Materials and Methods Wild type and hydrocephalic hyh mice at 30 days of postnatal age were used. Three metabolites related to the oxidative and neurotoxic conditions were analysed in ex vivo samples (glutathione, glutamine and taurine) using High Resolution Magic Angle Spinning (HR-MAS). Glutathione synthetase and peroxidase, glutamine synthetase, kidney-type glutaminase (KGA), and taurine/taurine transporter were immunolocated in brain sections. Results Levels of the metabolites were remarkably higher in hydrocephalic conditions. Glutathione peroxidase and synthetase were both detected in the periventricular reactive astrocytes and neurons. Taurine was mostly found free in the periventricular parenchyma and in the reactive astrocytes, and the taurine transporter was mainly present in the neurons located in such regions. Glutamine synthetase was found in reactive astrocytes. Glutaminase was also detected in the reactive astrocytes and in periventricular neurons. These results suggest a possible protective response of reactive astrocytes against oxidative stress and neurotoxic conditions. Conclusions Astrocyte reaction seems to trigger an anti-oxidative and anti-neurotoxic response in order to ameliorate pathological damage in periventricular areas of the hydrocephalic mice.

Growth, lipogenesis and body composition of piracanjuba (Brycon orbignyanus) fingerlings fed different dietary protein and lipid concentrations

Piracanjuba (Brycon orbignyanus) is a Brazilian migratory fast-growing omnivore, very appreciated as a sport fish, which is threatened to extinction in Southern Brazil due to stock over exploitation and dam building. Therefore, efforts have been made to raise this fish in captivity for reintroduction and aquaculture purposes. In the present study, the effects of different dietary protein and lipid concentrations on piracanjuba fingerlings growth performance, feed utilization, body composition, hepatosomatic index (HSI) and activity of the lipogenic enzymes fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME) were investigated using a 2 x 3 factorial experiment. Six casein-gelatin based diets were prepared combining two protein (30% and 32%) and three lipid concentrations (5.5%, 8.8% and 12.1%). Eleven fish, average weight 11.30 +/- 0.1 g, were held in each of 18 100-1 aquaria, supplied with recirculating freshwater. Each diet was randomly assigned to triplicate groups of fish and fed to apparent satiation, twice a day for 100 d. Piracanjuba fingerlings' daily weight gain (0.36-0.40 g), specific growth rate (1.43-1.51%), feed utilization and HSI were not influenced by dietary protein or lipid concentration. However, body composition was directly affected by dietary treatment. An increase in body fat and dry matter was observed as dietary lipid increased, for both dietary protein concentrations tested. The activity of FAS was depressed by increasing dietary fat levels but the G6PD activity did not differ among dietary treatments, although ME activity showed some regulation by dietary protein. These results indicate that an increase from 5.5% to 12.1% in the dietary lipid, at a dietary protein concentration of 30% or 32%, promotes body fat accumulation in piracanjuba fingerlings with no improvement in growth, suggesting that the lipid requirement for this species should be 5% or less, when raised for commercial purposes. However, the additional energy reserve from body fat accumulation could be desirable for piracanjuba fingerlings produced for stock enhancement. (C) 2003 Editions scientifiques et medicales Elsevier SAS and Ifremer/IRD/Inra/Cemagref. All rights reserved.