Retention of Virus Versus Surrogate, by Ultrafiltration in Seawater: Case Study of Norovirus Versus Tulane.

In the field of chemical engineering and water treatment, the study of viruses, included surrogates, is well documented. Often, surrogates are used to study viruses and their behavior because they can be produced in larger quantities in safer conditions and are easier to handle. In fact, surrogates allow studying microorganisms which are non-infectious to humans but share some properties similar to pathogenic viruses: structure, composition, morphology, and size. Human noroviruses, recognized as the leading cause of epidemics and sporadic cases of gastroenteritis across all age groups, may be mimicked by the Tulane virus. The objectives of this work were to study (i) the ultrafiltration of Tulane virus and norovirus to validate that Tulane virus can be used as a surrogate for norovirus in water treatment process and (ii) the retention of norovirus and the surrogate as a function of water quality to better understand the use of the latter pathogenic viruses. Ultrafiltration tests showed significant logarithmic reduction values (LRV) in viral RNA: around 2.5 for global LRV (i.e., based on the initial and permeate average concentrations) and between 2 and 6 for average LRV (i.e., retention rate considering the increase of viral concentration in the retentate), both for norovirus and the surrogate Tulane virus. Higher reduction rates (from 2 to 6 log genome copies) are obtained for higher initial concentrations (from 101 to 107 genome copies per mL) due to virus aggregation in membrane lumen. Tulane virus appears to be a good surrogate for norovirus retention by membrane processes.

Microplastics in different water samples (seawater, freshwater, and wastewater): Removal efficiency of membrane treatment processes.

The distribution and fate of microplastics in different water sources and their treatment plants (seawater, three municipal wastewaters, a pharmaceutical factory wastewater, and three drinking waters) in France were studied. Currently, research in this field is still under exploration since almost no relevant standards or policies have been introduced for the detection, the removal, or the discharge of microplastics. This study used an improved quantitative and qualitative analytical methodology for microplastic detection by µ-FTIR carried out with siMPle analytical software. By investigation, wastewater was determined to contain the most abundant microplastics in quantity (4,203-42,000 MP·L-1), then followed by surface water/groundwater (153-19,836 MP·L-1) and seawater (around 420 MP·L-1). Polyethylene was the dominant material in almost all water types followed by polypropylene, polystyrene, and polyethylene terephthalate. Almost all treatment technologies could remove microplastics whatever the feed water types and concentration of microplastics, though some treatment processes or transport pipes could cause additional contamination from microplastics. The four WWTPs, three DWTPs, and SWTP in France provided, respectively, 87.8-99.8%, 82.3-99.9%, 69.0-96.0% removal/retention of MPs in quantity, and provided 97.3-100%, 91.9-99.9%, 92.2-98.1% removal/retention of MPs in surface area. Moreover, ultrafiltration was confirmed to be an effective technology for microplastic retention and control of dimensions of microplastics in smaller ranges both in field-scale and lab-scale experiments. The 200 kDa ultrafiltration membrane could retain 70-100% and 80-100% of microplastics in quantity and in surface area, respectively.

Microplastics in different water samples (seawater, freshwater, and wastewater): Methodology approach for characterization using micro-FTIR spectroscopy.

Microplastics of millimeter dimensions have been widely investigated in environmental compartments and today, studies are mainly focused on particles of smaller dimensions (< 500 µm). However, as there are no relevant standards or policies for the preparation and analysis of complex water samples containing such particles, the results may be questionable. Therefore, a methodological approach for 10 µm to 500 µm microplastic analysis was developed using µ-FTIR spectroscopy coupled with the siMPle analytical software. This was undertaken on different water samples (sea, fresh, and wastewater) taking into consideration rinsing water, digestion protocols, collection of microplastics, and sample characteristics. Ultrapure water was the optimal rinsing water and ethanol was also proposed with a mandatory previous filtration. Although water quality could give some guidelines for the selection of digestion protocols, it is not the only decisive factor. The methodology approach by µ-FTIR spectroscopy was finally assessed to be effective and reliable. This improved quantitative and qualitative analytical methodology for microplastic detection can then be used to assess the removal efficiency of conventional and membrane treatment processes in different water treatment plants.

Membrane filtration coupled with wet air oxidation for intensified treatment of biorefractory effluents.

This work aims to analyse the performances of a new hybrid process: membrane filtration to concentrate biorefractory wastewater before treatment by a hydrothermal process such as wet air oxidation. The aim is to obtain a complete discharge of the effluent in the environment. The three different synthetic wastewaters under study were pharmaceutical wastewater, grey wastewater and bilge wastewater. The results of the membrane filtration showed high retention rates as it could reach between 75% and 100% of total organic carbon retention, more than 99% of turbidity removal and more than 70% of hydrocarbon retention. Moreover, it was possible to achieve high concentration factors comprised between 17 and 40 times. Membrane fouling was chemically reversible regardless of the type of pollution. Then, the treatment of the membrane retentates by wet air oxidation process (300 °C, 15 MPa) could eliminate more than 83% of organic pollution for all the tested effluents. In summary, the hybrid intensified process could finally decrease the volume and the waste load of wastewater before possibly discharging it into the environment.

Brewery wastewater treatment using MBR coupled with nanofiltration or electrodialysis: biomass acclimation and treatment efficiency.

Breweries release significant amounts of wastewater loaded with various organic and mineral materials. Prior studies of membrane bioreactor (MBR) wastewater treatment have been conducted with very little interest granted to the conditions of biomass acclimation. This study displays biomass behavior during brewery wastewater treatment by an aerobic MBR. In addition, nanofiltration and electrodialysis have been studied as potential post-treatment to decrease mineral concentrations and permit further water reuse for agriculture. An anoxic/aerobic laboratory MBR, associated with a flat sulfonated polyether membrane was used for synthetic brewery wastewater treatment. Biomass acclimation was performed using a feeding substrate. Organic concentrations in the MBR influent varied from 700 mg COD/L to 10,600 mg COD/L (COD: chemical oxygen demand) for 110 days. The results indicate a good acclimation to effluent with high salts and organic matter loads. Steady evolution of biomass concentration and activities was achieved after 90 days of operation. A reduction of COD of around 95% was obtained with MBR and up to 99% with nanofiltration post-treatment for the reconstructed brewery effluent with an organic loading rate of 7 g COD/L·d and a solid and hydraulic retention time of 30 days and 36 hours. A good reduction of the salt content was also recorded primarily with the nanofiltration and electrodialysis processes.

Efficacy of an activated charcoal-simethicone combination in dyspeptic syndrome: results of a randomized prospective study in general practice.

AIM: The aim of this prospective, multicenter, randomized, placebo-controlled trial was to evaluate the efficacy of a commercial combination of simethicone and activated charcoal (Carbosylane) on dyspeptic symptoms in patients consulting a general practitioner. PATIENTS AND METHODS: A total of 132 patients were studied. Treatment duration was 3 months, followed by a 2 months follow-up period. RESULTS: At the end of the treatment period, the percentage of patients with a reduction of at least two points on the symptom intensity scale was significantly higher with Carbosylane than with a placebo (P=0.043). Compared with placebo, the intensity of three symptoms (abdominal fullness, bloating and the sensation of slow digestion) was significantly decreased after 90 days of Carbosylane (P<0.05). At the end of the post-treatment follow-up, the percentages of patients with moderate or severe global complaints were 6.78% and 21.43% in the Carbosylane and placebo groups, respectively (P<0.03). CONCLUSION: Among patients consulting a general practitioner for dyspeptic syndrome, 3 months of treatment with Carbosylane resulted in significant symptomatic improvement. The improvement was still evident 2 months after the end of treatment.

Cholesterol dependent downregulation of mouse and human apical sodium dependent bile acid transporter (ASBT) gene expression: molecular mechanism and physiological consequences.

BACKGROUND AND AIMS: Faecal bile acid elimination greatly contributes to cholesterol homeostasis. Synthesised from cholesterol in the liver, bile acids are actively reclaimed in the ileum by the apical sodium dependent bile acid transporter (ASBT). Although the expression level of ASBT affects body cholesterol balance, the impact of cholesterol on ASBT gene expression remains unclear. In this study, the effect of cholesterol on ASBT expression and ileal bile acid uptake was explored in vivo and in vitro. METHODS: ASBT gene expression was assessed by real time quantitative polymerase chain reaction and northern or western blotting, or both, in mice subjected to a 2% cholesterol diet for two weeks, in mouse ileal explants, or in human enterocyte-like Caco-2 cells cultured in sterol enriched or depleted media. Bile acid uptake was determined by measuring [3H]-taurocholic acid influx into in situ isolated ileal loops from mice or into differentiated Caco-2 cells. Molecular analysis of mouse and human ASBT promoters was undertaken with reporter assays, site directed mutagenesis, and electrophoretic mobility shift assays. RESULTS: In mice, cholesterol enriched diet triggered a downregulation of ASBT expression (mRNA and protein), a fall in ileal bile acid uptake, and a rise in the faecal excretion of bile acids. This effect was direct as it was reproduced ex vivo using mouse ileal explants and in vitro in differentiated Caco-2 cells. CONCLUSIONS: This regulation, which involves an original partnership between SREBP-2 and HNF-1alpha transcription factors, affects ileal bile acid recycling and thus might participate in the maintenance of body cholesterol homeostasis.

Hyperinsulinaemia triggered by dietary conjugated linoleic acid is associated with a decrease in leptin and adiponectin plasma levels and pancreatic beta cell hyperplasia in the mouse.

AIMS/HYPOTHESIS: Dietary supplementation with conjugated linoleic acids (CLA) has a fat-reducing effect in various species, but induces severe hyperinsulinaemia and hepatic steatosis in the mouse. This study aimed to determine the causes of the deleterious effects of CLA on insulin homeostasis. METHODS: The chronology of adipose and liver weight, hepatic triglyceride accumulation and selected blood parameters, including lipids, insulin, leptin and adiponectin, was determined in C57BL/6J female mice fed a 1% isomeric mixture of CLA for various periods of time ranging from 2 to 28 days. Insulin secretion was measured in 1-h static incubations of pancreatic islets, and pancreas morphometric parameters were determined in mice fed CLA for 28 days. RESULTS: Plasma levels of leptin and adiponectin sharply decreased after 2 days of CLA feeding, although adipose tissue mass only decreased after day 6. Hyperinsulinaemia developed at day 6 and consistently worsened up to day 28, in parallel with increases in hepatic lipid content. Islets from CLA-fed mice displayed three- to four-fold increased rates of glucose-stimulated insulin secretion, both in the absence and presence of isobutyl methylxanthine or carbachol. The increased insulin-releasing capacity of islets from CLA-fed mice was explained by an increase in beta cell mass and number. CONCLUSIONS/INTERPRETATION: The data suggest that CLA supplementation induces a profound reduction of leptinaemia and adiponectinaemia, followed by hyperinsulinaemia due to the increased secretory capacity of pancreatic islets, leading, in turn, to liver steatosis. These observations cast doubt on the safety of dietary supplements containing CLA.

Differential involvement of peroxisome-proliferator-activated receptors alpha and delta in fibrate and fatty-acid-mediated inductions of the gene encoding liver fatty-acid-binding protein in the liver and the small intestine.

Liver fatty-acid-binding protein (L-FABP) is a cytoplasmic polypeptide that binds with strong affinity especially to long-chain fatty acids (LCFAs). It is highly expressed in both the liver and small intestine, where it is thought to have an essential role in the control of the cellular fatty acid (FA) flux. Because expression of the gene encoding L-FABP is increased by both fibrate hypolipidaemic drugs and LCFAs, it seems to be under the control of transcription factors, termed peroxisome-proliferator-activated receptors (PPARs), activated by fibrate or FAs. However, the precise molecular mechanism by which these regulations take place remain to be fully substantiated. Using transfection assays, we found that the different PPAR subtypes (alpha, gamma and delta) are able to mediate the up-regulation by FAs of the gene encoding L-FABP in vitro. Through analysis of LCFA- and fibrate-mediated effects on L-FABP mRNA levels in wild-type and PPARalpha-null mice, we have found that PPARalpha in the intestine does not constitute a dominant regulator of L-FABP gene expression, in contrast with what is known in the liver. Only the PPARdelta/alpha agonist GW2433 is able to up-regulate the gene encoding L-FABP in the intestine of PPARalpha-null mice. These findings demonstrate that PPARdelta can act as a fibrate/FA-activated receptor in tissues in which it is highly expressed and that L-FABP is a PPARdelta target gene in the small intestine. We propose that PPARdelta contributes to metabolic adaptation of the small intestine to changes in the lipid content of the diet.

Altered emotional perception in alcoholics: deficits in affective prosody comprehension.

BACKGROUND: Affective prosody is a nonlinguistic aspect of language that conveys emotion and attitude during discourse. It is a dominant function of the right hemisphere. Because skills associated with the right hemisphere have been found to be impaired in alcoholics, this study explored the possibility that affective prosodic functioning may be sensitive to the effects of alcohol due to heavy persistent drinking or prenatal exposure. METHODS: Subjects were aged 25 to 58 years. Twenty-nine men and three women who met DSM-IV criteria for an alcohol use disorder with a median of 39 days of sobriety, 11 men with a probable history of fetal alcohol exposure (FAexp), and 41 age-matched control subjects of both sexes were tested by using the Aprosodia Battery. This instrument assesses affective prosodic comprehension (APC) across a range of verbal articulatory demands. RESULTS: The alcoholic group scored 2 SD below the control mean, and the FAexp group scored -5 SD regardless of whether they had ever been diagnosed with alcohol abuse. Despite their poor performance on APC, alcoholic and FAexp groups performed similarly to the control group on vocabulary, abstract reasoning, and an index of cognitive impairment that used the Shipley Institute of Living Scale. Multiple regression analyses that used nine alcohol use variables to model APC resulted in four significant contributors to the effect. These regressors were related to early exposure to ethanol and chronicity of alcohol abuse. CONCLUSIONS: Alcoholics and FAexp subjects were significantly less accurate at APC compared with controls. These alcohol-exposed subjects appear to be deficient in the ability to understand emotional valence in the speech of others, which results in errors of judgment that may impair social interactions.

A DNA hairpin with a single residue loop closed by a strongly distorted Watson-Crick G x C base-pair.

Our previous NMR and modeling studies have shown that the single-stranded 19mer oligonucleotides d(AGCTTATC-ATC-GATAA GCT) -ATC- and d(AGCTTATC-GAT-GATAAGCT) -GAT- encompassing the strongest topoisomerase II cleavage site in pBR322 DNA could form stable hairpin structures. A new sheared base-pair, the pyrimidine-purine C x A, was found to close the single base -ATC- loop, while -GAT- displayed a flexible loop of three/five residues with no stabilizing interactions. Now we report a structural study on -GAC-, an analog of -GAT-, derived through the substitution of the loop residue T by C. The results obtained from NMR, non-denaturing PAGE, UV-melting, circular dichroism experiments and restrained molecular dynamics indicate that -GAC- adopts a hairpin structure folded through a single residue loop. In the -GAC- hairpin the direction of the G9 sugar is reversed relative to the C8 sugar, thus pushing the backbone of the loop into the major groove. The G9 x C11 base-pair closing the loop is thus neither a sheared base-pair nor a regular Watson-Crick one. Although G9 and C11 are paired through hydrogen bonds of Watson-Crick type, the base-pair is not planar but rather adopts a wedge-shaped geometry with the two bases stacked on top of each other in the minor groove. The distortion decreases the sugar C1'-C1' distance between the paired G9 and C11, to 8 A versus 11 A in the standard B-DNA. The A10 residue at the center of the loop interacts with the G9 x C11 base-pair, and seems to contribute to the extra thermal stability displayed by -GAC- compared to -GAT-. Test calculations allowed us to identify the experimental NOEs critical for inducing the distorted G.C Watson-Crick base-pair. The preference of -GAC- for a hairpin structure rather than a duplex is confirmed by the diffusion constant values obtained from pulse-field gradient NMR experiments. All together, the results illustrate the high degree of plasticity of single-stranded DNAs which can accommodate a variety of turn-loops to fold up on themselves.

An NMR and molecular modelling analysis of d(CTACTGCTTTAG). d(CTAAAGCAGTAG) reveals that the particular behaviour of TpA steps is related to edge-to-edge contacts of their base-pairs in the major groove.

In a previous NMR study we detected the presence of particular motions and hydration properties within the DNA fragment d(CTACTGCTTTAG).d(CTAAAGCAGTAG). Now, we report on an NMR and molecular modelling analysis of this sequence focusing our attention on the biologically important TpA steps. NOe and coupling constant restraints were introduced in three different modelling protocols: X-PLOR and JUMNA used with Flex and AMBER94 as force-fields. Despite their differences the protocols produce similar mean B-DNA structures (r.m.s.d. <1 A). The new information confirms our previous experimental results on the narrowing of the minor groove along the T8T9T10/A17A16A15 run and the sudden widening at the T10pA11 step ending this run. It is further shown that this step displays a large positive roll with its T10:A15 and A11:T14 base-pairs likely stabilised by amino-amino and amino-carbonyl interactions in the major groove. A relationship between roll values and amino-amino and amino-carbonyl distances strongly suggests that electrostatics or bifurcated hydrogen-bonds could be responsible for induction of positive rolls in TpA steps. Such edge-to-edge interactions could explain the slower motions shown by the adenine A15. The influence of these interactions on the stabilisation of particular DNA conformers is discussed using our data and those provided by the recent literature.

Epidermal expression of apolipoprotein E gene during fin and scale development and fin regeneration in zebrafish.

Apolipoprotein E (apoE) plays an important role in systemic and local lipid homeostasis. We have examined the expression of apoE during morphogenesis and regeneration of paired and unpaired fins and during scale development in zebrafish (Danio rerio). In situ hybridization analysis revealed that, during embryogenesis, apoE is expressed in the epithelial cells of the median fin fold and of the pectoral fin buds. ApoE remains expressed in the elongating fin folds throughout development of the fins. During the larval to juvenile transition, apoE transcripts were present in the distal, interray and lateral epidermis of developing fins. Furthermore, as scale buds started to form, apoE was expressed in large scale domains which later, became restricted to the external posterior epidermal part of scales. A low level of transcripts could be observed at later developmental stages at these locations probably because fins and scales continue to grow throughout the animal's life. During regeneration of both pectoral and caudal fins, a marked increase in apoE expression is observed as early as 12 hours after amputation in the wound epidermis. High levels of apoE transcripts are then localized primarily in the basal cell layer of the apical epidermis. The levels of apoE expression were maximum between the second to fourth days and then progressively declined to basal level by day 14. ApoE transcripts were also observed in putative macrophages infiltrated in the mesenchymal compartment of regenerating fins a few hours after amputation. In conclusion, apoE is highly expressed in the epidermis of developing fins and scales and during fin regeneration while no expression can be detected in the skin of the trunk. ApoE may play a specific role in fin and scale differentiation at sites where important epidermo-dermal interactions occur for the elaboration of the dermal skeleton and/or for lipid uptake and redistribution within these rapidly growing structures.

Function of infant-directed speech.

The relationship between a biological process and a behavioral trait indicates a proximate mechanism by which natural selection can act. In that context, examining an aspect of infant health is one method of investigating the adaptive significance of infant-directed speech (ID speech), and it could help to explain the widespread use of this communication style. The correlation between infant growth and infant-directed speech is positive and significant, and provides a vehicle for testing evolutionary history hypotheses.

Comparative structural analysis by [1H,31P]-NMR and restrained molecular dynamics of two DNA hairpins from a strong DNA topoisomerase II cleavage site.

The structural analysis of two single-stranded DNAs d(AGCTTATCATCGATAAGCT) (ATC-19) and d(AGCTTATCGATGATAAGCT) (GAT-19) was performed by NMR and restrained molecular dynamics. These oligonucleotides reproduce the 15-33 segment of phage pBR322 DNA, which contains a strong cleavage site for topoisomerase II coupled to the antitumor drugs VP-16 and ellipticine. Because of their partial palindromic nature, the two oligonucleotides ATC-19 and GAT-19 may fold back into stable hairpin structures, consisting of a stem of eight base-pairs and a loop of three residues. NMR assignments and conformational parameters were determined from combined 2D NOESY, COSY and 1H-31P spectra. Conformations of ATC-19 and GAT-19 hairpins were calculated using the X-PLOR 3.1 program. Structures were generated through simulated annealing procedures starting from 50 structures with randomized torsion angles. A good convergence was observed for ATC-19 molecules, while no consensus was found for GAT-19. Within the GAT-19 loop, the base stacking was poor and no hydrogen bond could be detected. In contrast, ATC-19 displayed a well-defined three residue loop stabilized by both extensive base stackings and hydrogen bonding between the N3 atom of the adenine ring and the amino group of the cytosine ring. The results confirm our earlier ATC-19 structure obtained by a completely different calculation procedure (JUMNA) and the higher thermal stability of ATC-19 compared to GAT-19. Moreover, due to its mismatched base-pair, the ATC-19 loop may be better described as a single residue loop rather than a three residue loop. Comparison of this loop to those containing sheared purine.purine base-pairs revealed striking resemblances, particularly on the backbone angle combination. Finally, the differences observed between the ATC-19 and GAT-19 structures could help toward understanding the sequential cleavage of DNA strands by topoisomerase II.

Expression of two even-skipped genes eve1 and evx2 during zebrafish fin morphogenesis and their regulation by retinoic acid.

Growth and patterning during fin regeneration depend, like for fin development, on the integrated expression of homeogenes. In the present work we have studied, by in situ hybridization, the expression and regulation of two vertebrate homologs eve1 and evx2 of the Drosophila pair-rule even-skipped gene family. Upon amputation of pectoral and caudal fins, both genes, expressed transiently in the mesenchyme during early stages of fin development of these fins, are turned on. During the formation of the blastema they are transcribed first in the mesenchyme located underneath the wound epidermis and then, their expression is restricted to the regenerating rays regions. These expression patterns are developmentally regulated since both genes are no longer transcribed when the bony rays are differentiating. Exposure of the regenerates to retinoic acid (RA) modifies the boundaries of eve1 and evx2 expression: the signal is down-regulated in the ray region and up-regulated in the interray region. Moreover, expression is induced in the wound epidermis. These results indicate that eve1 and evx2 products are part of the molecular signals involved in pattern formation of the fin and fin rays in connection with outgrowth. RA might alter growth and morphogenesis of the regenerating fins by a fine regulation of these genes among others.

Fatty acid regulation of fatty acid-binding protein expression in the small intestine.

The effects of dietary oil intake and fatty acid infusions on the expression of intestinal and liver fatty acid-binding proteins (I-FABP and L-FABP, respectively) were investigated in the small intestine of mice. A daily force-feeding for 7 days with 0.2 ml sunflower oil specifically increased L-FABP mRNA and protein levels in duodenum and proximal jejunum. This upregulation was mediated in time- and dose-dependent manners by a minute quantity of linoleic acid, the main fatty acid found in sunflower oil. The L-FABP induction was only found with long-chain fatty acids, with the nonmetabolizable, substituted fatty acid alpha-bromopalmitate being far more active. A hormonally mediated effect is unlikely because long-chain fatty acids induced L-FABP mRNA in the Caco-2 cell line cultured in serum-free medium. Therefore, long-chain fatty acids are strong inducers of L-FABP gene expression in the small intestine. In contrast to data found in the rat, I-FABP gene expression appears to be unaffected by a lipid-enriched diet in the mouse.

The ETS family member ERM contains an alpha-helical acidic activation domain that contacts TAFII60.

Transcription factors are modular entities built up of discrete domains, some devoted to DNA binding and others permitting transcriptional modulation. The structure of DNA binding domains has been thoroughly investigated and structural classes clearly defined. In sharp contrast, the structural constraints put on transactivating regions, if any, are mostly unknown. Our investigations focus on ERM, a eukaryotic transcription factor of the ETS family. We have previously shown that ERM harbours two transactivating domains (TADs) with distinct functional features: AD1 lies in the first 72 amino acids of ERM, while AD2 sits in the last 62. Here we show that AD1 is a bona fide acidic TAD, for it activated transcription in yeast cells, while AD2 did not. AD1 contains a 20 amino acid stretch predicted to form an alpha-helix that is found unchanged in the related PEA3 and ER81 transcription factors. Circular dichroism analysis revealed that a 32 amino acid peptide encompassing this region is unstructured in water but folds into a helix when the hydrophobic solvent trifluoroethanol is added. The isolated helix was sufficient to activate transcription and mutations predicted to disrupt it dramatically affected AD1-driven transactivation, whereas mutations decreasing its acidity had more gentle effects. A phenylalanine residue within the helix was particularly sensitive to mutations. Finally, we observed that ERM bound TAFII60 via AD1 and bound TBP and TAFII40, presumably via other activation domains.

Dissection of the basic subdomain of the c-Jun oncoprotein: a structural analysis of two peptide fragments by CD, Fourier-transform infrared and NMR.

In a previous paper, we reported on the structural properties of a 35-residue peptide corresponding to a modified basic subdomain (bSD) of the basic zipper protein c-Jun (residues 252-281) as determined by combined use of 1H-NMR, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopies [Krebs, D., Dahmani, B., El Antri, S., Monnot, M., Convert, O,. Mauffret, O., Troalen, F. & Fermandjian, S. (1995) Eur. J. Biochem. 231, 370-380]. The fragments NP and CP (the N-terminal residues 1-19 and C-terminal residues 16-35 of bSD, respectively) proved to be particularly useful for the assignment of the 1H-NMR spectra of the full-length bSD, which has been achieved completely in aqueous solution and partially in trifluoroethanol. Here, we report on the structural properties of NP and CP in aqueous solution and under varying H2O/trifluoroethanol conditions, again using 1H-NMR, CD and FT-IR experiments. Both CD and FT-IR results established that the fragments are weakly structured in aqueous solution. Addition of trifluoroethanol to aqueous solutions of the peptides produced their stabilization into helix, following a profile sigmoidal for NP and nearly linear for CP. Quantitative NOEs, secondary Halpha chemical shifts, NH temperature coefficients and 3JalphaN coupling constants for the peptides in aqueous solutions provided indications for weak helix features (nascent helices) manifested within two sites (continuous dNN NOEs) in both NP and CP. For each peptide, an excellent agreement was observed between experiments and predictions with the AGADIR program for the location of these nascent helices in the sequences. Trifluoroethanol provoked both the alpha-helix stabilization within these sites and the alpha-helix propagation to adjacent amino acid residues. Finally, our results reflected the high flexibility and helix potential of the NP and CP fragments, these two properties seeming crucial for the accommodation of c-Jun to its specific DNA targets. The results demonstrated also the fragmentation's benefits in dissecting a protein or a complex peptide into smaller fragments and analyzing their structure individually.