Pollinators of the sea: A discovery of animal-mediated fertilization in seaweed

The long-held belief that animal-mediated pollination is absent in the sea has recently been contradicted in seagrasses, motivating investigations of other marine phyla. This is particularly relevant in red algae, in which female gametes are not liberated and male gametes are not flagellated. Using experiments with the isopod Idotea balthica and the red alga Gracilaria gracilis, we demonstrate that biotic interactions dramatically increase the fertilization success of the alga through animal transport of spermatia on their body. This discovery suggests that animal-mediated fertilization could have evolved independently in terrestrial and marine environments and raises the possibility of its emergence in the sea before plants moved ashore.

Effect of age at cochlear implantation and at exposure to Cued Speech on literacy skills in deaf children

The aim of this study was to investigate how age at cochlear implantation (CI) and age at exposure to Cued Speech (CS, Manual system that resolves the ambiguity inherent lipreading) could impact literacy skills in deaf children. Ninety deaf children fitted with CI (early vs late) and exposed to CS (early vs late) from primary schools (from Grade 2 to Grade 5) took part in this study. Five literacy skills were assessed: phonological skills through phoneme deletion, reading (decoding and sentence comprehension), word spelling and vocabulary. The results showed that both age at CI and age at first exposure to CS had some influence on literacy skills but there was no interaction between these factors. This implies that the positive effects of age at CI, especially on all literacy skills in the younger children, were not strengthened by age at exposure to CS.

Photo-elicitation with adolescents in qualitative research: an example of its use in exploring family interactions in adolescent psychiatry

BACKGROUND

Photo-elicitation is a method used increasingly often in qualitative health research, and its positive effect on the research process is well established today. Photo-elicitation appears to facilitate verbalization and insight and to improve relationships between the researcher and participants, thereby enriching the quality of the data collected. Nonetheless, it is barely used at all in the field of adolescent psychiatry. With the aim of exploring the potential of these methods for research with adolescents receiving psychiatric care, we conducted a qualitative photo-elicitation data collection study with this population, asking them about family interactions around food.

METHODS

The data were collected from 15 adolescents and 17 parents during semi-structured interviews in which a photo taken by the adolescent served as the focus of discussion. Data were explored through inductive thematic analysis.

RESULTS

Photo-elicitation played a threefold role in this study: (1) it induced the teens' interest, thought, and pleasure, (2) it played a mediating function during the interviews, and (3) it enabled family interactions to be viewed from the adolescent's perspective. Three themes concerning family interactions were found: (1) parent-child relationship patterns, (2) the functioning of the family group, and (3) the adolescent's individual relation with food, that is, the issue of the adolescent's autonomy.

CONCLUSIONS

Photo-elicitation proved to be an innovative technique in qualitative research in the area of adolescent psychiatry, one that enriched the data and enabled the emergence of new themes in this field, related in particular to the process by which adolescents develop autonomy.

The neuron-derived orphan receptor 1 (NOR1) is induced upon human alternative macrophage polarization and stimulates the expression of markers of the M2 phenotype

BACKGROUND

Atherosclerosis is an inflammatory disease in which macrophages play a crucial role. Macrophages are present in different phenotypes, with at the extremes of the spectrum the classical M1 pro-inflammatory and the alternative M2 anti-inflammatory macrophages. The neuron-derived orphan receptor 1 (NOR1), together with Nur77 and Nurr1, are members of the NR4A orphan nuclear receptor family, expressed in human atherosclerotic lesion macrophages. However, the role of NOR1 in human macrophages has not been studied yet.

OBJECTIVES

To determine the expression and the functions of NOR1 in human alternative macrophages.

METHODS AND RESULTS

In vitro IL-4 polarization of primary monocytes into alternative M2 macrophages enhances NOR1 expression in human but not in mouse macrophages. Moreover, NOR1 expression is most abundant in CD68+MR+ alternative macrophage-enriched areas of human atherosclerotic plaques in vivo. Silencing NOR1 in human alternative macrophages decreases the expression of several M2 markers such as the Mannose Receptor (MR), Interleukin-1 Receptor antagonist (IL-1Ra), CD200 Receptor (CD200R), coagulation factor XIII A1 polypeptide (F13A1), Interleukin 10 (IL-10) and the Peroxisome Proliferator-Activated Receptor (PPAR)γ. Bioinformatical analysis identified F13A1, IL-1Ra, IL-10 and the Matrix Metalloproteinase-9 (MMP9) as potential target genes of NOR1 in human alternative macrophages. Moreover, expression and enzymatic activity of MMP9 are induced by silencing and repressed by NOR1 overexpression in M2 macrophages.

CONCLUSIONS

These data identify NOR1 as a transcription factor induced during alternative differentiation of human macrophages and demonstrate that NOR1 modifies the alternative macrophage phenotype.

The development of word recognition, sentence comprehension, word spelling, and vocabulary in children with deafness: a longitudinal study

BACKGROUND

Only a small number of longitudinal studies have been conducted to assess the literacy skills of children with hearing impairment. The results of these studies are inconsistent with regard to the importance of phonology in reading acquisition as is the case in studies with hearing children. Colin, Magnan, Ecalle, and Leybaert (2007) revealed the important role of early phonological skills and the contribution of the factor of age of exposure to Cued Speech (CS: a manual system intended to resolve the ambiguities inherent to speechreading) to subsequent reading acquisition (from kindergarten to first grade) in children with deafness. The aim of the present paper is twofold: (1) to confirm the role of early exposure to CS in the development of the linguistic skills necessary in order to learn reading and writing in second grade; (2) to reveal the possible existence of common factors other than CS that may influence literacy performances and explain the inter-individual difference within groups of children with hearing impairment.

METHOD

Eighteen 6-year-old hearing-impaired and 18 hearing children of the same chronological age were tested from kindergarten to second grade. The children with deafness had either been exposed to CS at an early age, at home and before kindergarten (early-CS group), or had first been exposed to it when they entered kindergarten (late-CS group) or first grade (beginner-CS group). Children were given implicit and explicit phonological tasks, silent reading tasks (word recognition and sentence comprehension), word spelling, and vocabulary tasks.

RESULTS

Children in the early-CS group outperformed those of the late-CS and beginner-CS groups in phonological tasks from first grade to second grade. They became better readers and better spellers than those from the late-CS group and the beginner-CS group. Their performances did not differ from those of hearing children in any of the tasks except for the receptive vocabulary test. Thus early exposure to CS seems to permit the development of linguistic skills necessary in order to learn reading and writing. The possible contribution of other factors to the acquisition of literacy skills by children with hearing impairment will be discussed.

A novel mcl PHA-producing bacterium, Pseudomonas guezennei sp. nov., isolated from a 'kopara' mat located in Rangiroa, an atoll of French Polynesia

AIMS

The aim of the present study was to describe an aerobic, mesophilic and heterotrophic bacterium, designated RA26, able to produce a medium-chain-length polyhydroxyalkanoate (PHA). It was isolated from a French Polynesian bacterial mat located in the atoll of Rangiroa.

METHODS AND RESULTS

This micro-organism, on the basis of the phenotypical features and genotypic investigations can be clearly assigned to the Pseudomonas genus and the name of Pseudomonas guezennei is proposed. Optimal growth occurs between 33 and 37 degrees C, at a pH between 6.4 and 7.1 and at ionic strength of 15 g l(-1) of sea salts. The G+C content of DNA is 63.2%. Under laboratory conditions, this bacterium produced a novel, medium-chain-length PHA, mainly composed of 3-hydroxydecanaote (64 mol.%) and 3-hydroxyoctanoate (24 mol.%) (GC-MS, NMR) from a single nonrelated carbon substrate, i.e. glucose.

CONCLUSIONS

The bacterium P. guezennei produces a novel PHA mcl with elastomeric properties.

SIGNIFICANCE AND IMPACT OF THE STUDY

PHAs share physical and material properties that recommend them for application in various areas, and are considered as an alternative to nonbiodegradable plastics produced from fossil oils. In this study, we describe a new bacteria with the capability to synthesize a novel PHA with promising biotechnological applications.

Relation between deaf children's phonological skills in kindergarten and word recognition performance in first grade

BACKGROUND

The aim of the present study was twofold: 1) to determine whether phonological skills measured in deaf prereaders predict their later phonological and reading skills after one year of reading instruction as is the case for hearing children; 2) to examine whether the age of exposure to a fully specified phonological input such as Cued Speech may explain the inter-individual differences observed in deaf children's phonological and word recognition levels.

METHOD

Twenty-one 6-year-old deaf prereaders and 21 hearing children of the same chronological age performed two phonological tasks (rhyme decision and generation tasks); they were re-assessed 12 months later and presented with other phonological tasks (rhyme decision and common unit identification tasks) and a written word choice test.

RESULTS

Phonological skills measured before learning to read predicted the written word recognition score the following year, both for hearing and for deaf participants. Age of onset of exposure to Cued Speech was also a strong predictor of phonological and written word recognition scores in beginning deaf readers.

CONCLUSIONS

The evidence broadly supports the idea of a capacity for acquiring phonological skills in deaf children. Deaf children who are able to develop an implicitly structured phonological knowledge before learning to read will be better readers when this knowledge becomes explicit under the pressure of reading instruction.

The dentino-enamel junction revisited

The dentino-enamel junction is not an simple inert interface between two mineralized structures. A less simplistic view suggests that the dentino-enamel junctional complex should also include the inner aprismatic enamel and the mantle dentin. At early stages of enamel formation, fibroblast growth factor (FGF)-2 is stored in and released from the inner aprismatic enamel, possibly under the control of matrix metalloproteinase (MMP)-3. The concentration peak for MMP-2 and -9 observed in the mantle dentin coincided with a very low labeling for TIMP-1 and -2, favoring the cross-talk between mineralizing epithelial and connective structures, and as a consequence the translocation of enamel proteins toward odontoblasts and pulp cells, and vice versa, the translocation of dentin proteins toward secretory ameloblasts and cells of the enamel organ. Finally, in X-linked hypophosphatemic rickets, large interglobular spaces in the circumpulpal dentin were the major defect induced by the gene alteration, whereas the mantle dentin was constantly unaffected. Altogether, these data plead for the recognition of the dentino-enamel junctional complex as a specific entity bearing its own biological characteristics.

In vivo involvement of heparan sulfate proteoglycan in the bioavailability, internalization, and catabolism of exogenous basic fibroblast growth factor

The in vivo bioavailability of exogenous fibroblast growth factor 2 (FGF2) was studied after i.v. injection of uniformly 14C-labeled FGF2 into young rats. 14C-FGF2 was rapidly accumulated in almost all solid organs within 5 min. After 30 min, more than 65% of FGF2 was retained in liver, 4.5% in kidneys, 1.2% in spleen, 0.15% in adrenal glands, and trace amounts in bone marrow, eyes, lungs, and heart. Suborgan distribution of 14C-FGF2 showed that for kidneys and adrenal glands, the labeling was mainly concentrated in the cortical zone. Incubation of organ sections with 2 M NaCl or heparin eluted all the radioactivity, indicating that labeling was due to FGF2-heparan sulfate proteoglycan (HSPG) interactions. Electrophoretic analysis show only native 14C-FGF2 in the blood and extracellular matrix; however, FGF2 is continuously catabolized in solid organs, indicating that all participate in the clearance of FGF2 by cellular internalization and subsequent catabolism. All FGF2 catabolic fragments bound heparin, demonstrating the preservation of their HSPG-binding site during the in vivo intracellular catabolism of FGF2. Analysis of the high-affinity receptors of FGF2 (FGFR-1 and FGFR-3) and the mitogen-activated protein kinase did not show any increase in either FGFR tyrosine phosphorylation or in mitogen-activated protein kinase activation. This study shows for the first time that exogenous FGF2 is cleared by HSPG cellular internalization and catabolism without inducing the activation of FGFRs within at least five organs in vivo, which strongly suggests that the HSPG-dependent internalization and catabolism pathway may control the in vivo bioavailability of FGF2.

Comparative study in vivo and in vitro of uniformly 14C-labelled and 125I-labelled recombinant fibroblast growth factor 2

Recombinant bovine fibroblast growth factor (FGF2), uniformly labelled with 14C ([14C]FGF2), was purified and showed to be highly stable and to retain full biological activity. Organ distribution of [14C]FGF2 after intravenous injection of young rats was assessed by autoradiography of whole body sections and compared with those obtained with [125I]iodinated FGF2 (125I-FGF2). Thyroid, stomach, intestine, bladder and skin were radioactively labelled only in the case of 125I-FGF2. This tissue-labelling is artefactual, probably due to free iodide binding not observed when using [14C]FGF2. High-resolution autoradiography showed a complex tissue distribution of [14C]FGF2 in kidney and adrenal organs. Incubation of frozen eye sections with [14C]FGF2 showed a specific and high-resolution labelling pattern of ocular tissues. After cellular internalization, [14C]FGF2 was processed into five distinct polypeptides of 16, 14, 8, 7, and 5.5 kDa. The 14-kDa and 7-kDa polypeptides are novel catabolic fragments not detected with radioiodinated FGF2. In terms of stability, tissue distribution specificity, and autoradiographic resolution, [14C]FGF2 proved to have more advantages than 125I-FGF2 for pharmacokinetic and catabolism studies.

Evaluation of the E test for fluconazole susceptibility testing of Candida albicans isolates from oropharyngeal candidiasis

The aim of the present study was to evaluate the utility of the E test in determining the antifungal susceptibility of Candida albicans. Reproducibility of the E test was determined for amphotericin B, fluconazole, and itraconazole using three different solid media: RPMI 1640, Casitone, and yeast nitrogen base agar. Minimum inhibitory concentrations (MICs) were comparable (results at +/- 2 dilutions) in 92% of the tests for amphotericin B and in 100% for fluconazole and itraconazole. Determination of MIC endpoints was easiest on Casitone agar. Candida albicans isolates from 23 patients undergoing fluconazole therapy for oropharyngeal candidiasis were tested for fluconazole susceptibility. Good correlation was obtained between the MICs of fluconazole and clinical outcome. Clinical failure was associated with strains for which MICs were > or = 48 micrograms/ml. These results suggest that the E test has potential utility for fluconazole susceptibility testing of clinical yeast isolates.

Evidence of a saturable-absorption effect in heavily erbium-doped fibers

A new configuration for erbium-doped fiber lasers in which two different connected fibers are used is studied: one is heavily and the other weakly doped. It is demonstrated that the dynamics of such a system depends on the fiber into which the pump is injected. The experimental results are interpreted in the framework of an ion-pair interaction model.

Central nervous system distribution of fibroblast growth factor injected into the blood stream

It has been shown that fibroblast growth factors (FGFs) protect hypocampal CAI cells from the effects of transient ischemia when injected either intraventrically or intravenously. The effectiveness of the systemic treatment seems to suggest that FGFs cross the blood-brain barrier to some extent. The appearance of basic fibroblast growth factor (bFGF) in the rat central nervous system after systemic administration have been autoradiographically examined using a 14C uniformly labeled preparation. Our results show that, two hours after a systemic bolus administration, bFGF spots in several populations of neuronal and in non-neural cells except in glial cells. Label accumulation was imperceptible when either 14C-bFGF was heated previously to the systemic injection or was co-administered with an excess of unlabeled bFGF. Our results indicate the existence of a saturable transport system of FGFs across the blood-brain barrier.

Peroxisomes and peroxisomal enzymes in the human fetal small intestine

The appearance and development of peroxisomes and the expression of their enzymes in the human fetal intestine have been investigated between 11 and 22 weeks of gestation. In the youngest samples (11-16 weeks of age), cytochemistry at the ultrastructural level revealed the presence of rare, mostly circular peroxisomes. From 16 weeks of gestation onwards, an increase was noted in the number of peroxisomes. Two peroxisomal types were distinguished: round to oval forms and elongated and/or tailed organelles. Biochemical assays revealed that total and specific intestinal catalase activities increased gradually between 11 and 20 weeks of gestation. The activity of fatty acylCoA oxidase, the first enzyme of the peroxisomal beta-oxidation system, was detectable as early as 11 weeks of gestation. Thereafter, total and specific activities of the enzyme increased steadily. Activities of other peroxisomal oxidases (D-amino acid oxidase, L-alpha-hydroxyacid oxidase) appeared more slowly in the fetal intestine during the period studied. This investigation establishes the presence and the morphological changes that occur in intestinal peroxisomes during human fetal development as well as the developmental patterns of associated enzymes.

Peroxisome through cell differentiation and neoplasia

Peroxisomes are essential in cellular metabolism as their dysgenesis or defects in single enzymes or impairment of multiple peroxisomal enzymatic functions have been found in several inherited metabolic diseases with serious clinical sequelae. The assembly and formation of these cytoplasmic organelles constitute a major and intriguing research topic. In the present study the biogenesis of peroxisomes and the developmental patterns of their enzymes have been reviewed during embryonic and/or post-embryonic ontogenesis of lower (amphibians) and higher (avians, mammals) vertebrates. In developing vertebrates, epithelial cell differentiation is accompanied by increases in frequency and size of peroxisomes. The tissue-specific expression of peroxisomal enzymes contributes substantially to the biochemical maturation of epithelial cells. The relationship between biogenesis of peroxisomes, expression of peroxisomal enzymes and structural and functional cellular phenotype has also been investigated in differentiating epithelial cells along the crypt-villus axis of the adult rat intestine. Cytochemical studies at the ultrastructural level have provided evidence that peroxisomes are already present in proliferating cells of the intestinal crypt region before they begin to differentiate. Migration and differentiation of intestinal epithelial cells from crypt to villus compartments are marked by significant increases in number and size of catalase-positive structures. Increasing activity gradients from crypt to surface areas are found for the peroxisomal oxidases examined (enzymes of the peroxisomal beta-oxidation system, D-amino acid oxidase and polyamine oxidase). Thus, peroxisomes are more and more involved in oxidative metabolic pathways as intestinal epithelial cells differentiate. Finally, we have analyzed the peroxisomal behaviour in human neoplastic epithelial cells. The presence of peroxisomes has been cytochemically revealed in human breast and colon carcinomas. Peroxisomal enzyme specific activities are significantly lower in human breast and colon carcinomas than in the adjacent healthy mucosa. Furthermore, a relationship is found between the specific activities of some peroxisomal enzymes and the histological tumour grades.

Peroxisomes in human colon carcinomas. A cytochemical and biochemical study

The presence of peroxisomes and their enzymic content were investigated and compared in healthy and neoplastic human colon epithelial cells using cytochemical studies at the ultrastructural level as well as biochemical analyses. Catalase-positive organelles were found to be more numerous in normal than in colonic neoplastic cells. Biochemical assays revealed that no D-aminoacid oxidase or L-alpha-hydroxyacid oxidase activity was detected in normal or tumor tissues. The specific activities of catalase, fatty-acyl CoA oxidase and enoyl-CoA hydratase/3 hydroxyacyl-CoA dehydrogenase (the so-called peroxisomal bifunctional enzyme of the beta-oxidation system) were found to be diminished in carcinoma cells compared with the control tissue. The fall in catalase activity correlated well with tumor stage according to Dukes, suggesting that this peroxisomal enzyme could be used as a potential prognostic marker.

Amphibian intestinal villin: isolation and expression during embryonic and larval development

An actin-binding protein of M(r) 105,000 has been isolated from anuran amphibian intestinal mucosa. Polyclonal antibodies directed against chicken and pig intestinal villins and anti-porcine villin headpiece monoclonal antibody crossreact with the amphibian M(r) 105,000 protein. Furthermore, the latter possesses an NH2-terminal sequence that is very homologous to those of avian and mammalian villins. In addition, polyclonal antibodies directed against amphibian intestinal M(r) 105,000 protein crossreact with chicken and mouse intestinal epithelial cell villins. These data indicate that the amphibian intestinal M(r) 105,000 protein is immunologically and structurally related to villin, an actin-binding protein expressed in specific epithelial tissues in vertebrates. Morphological, immunocytochemical and immunoblotting techniques were then used to investigate the expression of villin during embryonic and larval intestinal development of Xenopus laevis. Villin is not found in the egg or the endoderm of the early embryo. It is first detected just before hatching in the apical domain of endodermal cells at a time when few surface microvilli are visible by transmission electron microscopy. In the newly hatched larva, villin accumulates as these cells differentiate. These results provide a detailed developmental profile of Xenopus intestinal villin expression and demonstrate that this protein is a useful marker for the presumptive intestinal endoderm.

Peroxisomal enzymes in normal and tumoral human breast

The presence of peroxisomes and their enzymatic content were investigated and compared in healthy and neoplastic human breast epithelial cells using cytochemical studies at the ultrastructural level as well as Western blot and biochemical analyses. Ultrastructural cytochemistry revealed the presence of these organelles in both normal and neoplastic breast tissues. Their mean diameter was 0.27 +/- 0.11 micron. No significant difference was noted between numbers of peroxisomes in normal and neoplastic breast epithelia. Catalase, D-amino acid oxidase, and urate oxidase were found to be expressed in mammary carcinoma and in surrounding non-malignant tissue when the postnuclear supernatant fractions prepared from homogenates were assessed by Western blot techniques. Their specific activities and that of fatty acyl CoA oxidase as determined spectrophotometrically were found to be diminished in the tumour when compared with the control tissue. On the other hand, no significant difference was found in the specific activity of the L-alpha-hydroxy acid oxidase of normal and neoplastic human breast tissues. Investigations of the relationship between peroxisomal enzymes and tumour grade revealed that catalase, urate oxidase, and fatty acyl CoA oxidase activities in breast neoplastic tissues belonging to grade III were significantly lower than in the adjacent normal tissues.

Kluyveromyces bulgaricus yeast lectins. Isolation of two galactose-specific lectin forms from the yeast cell wall

Incubation of galactose treated Kluyveromyces bulgaricus yeast cells in EDTA/phosphate-buffered saline led to an extract possessing hemagglutinating and yeast flocculating properties. Purification of this extract by affinity chromatography and gel filtration gave two lectin forms, Kb-CWL I and Kb-CWL II, with an apparent molecular mass of 38,000 and 150,000 Da, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that Kb-CWL I and Kb-CWL II were dimeric and octameric of a subunit of 18,900 Da. At high concentration, purified Kb-CWL I associated to give Kb-CWL II. This association seemed to be independent on pH. The two lectin forms were glycoproteins, the peptide counterpart was very rich in Lys, Glu, and Gly, and the carbohydrate part represented 1% of the whole molecule and was composed of Glc, Man, and Ara. The two lectin forms (KB-CWL I and Kb-CWL II) agglutinated human red blood cells and flocculated EDTA-treated K. bulgaricus yeast cells. The activity of both lectin forms required Ca2+ ions, while Sr2+ showed some competitive inhibition. Optimal activity was obtained within a pH range of 4-6.5 for both forms. Temperatures of 80-90 degrees C for 20 min, or proteolytic treatment reduced irreversibly the activity of Kb-CWL I and Kb-CWL II. The role of the cell wall phosphopeptidomannan as a ligand and a potential physiological receptor of these lectin forms was demonstrated.

Development of the vertebrate small intestine and mechanisms of cell differentiation

The intestinal epithelium represents an attractive biological model of differentiation from stem cells to highly differentiated epithelial cells, not only during particular developmental events depending upon the vertebrate species considered but also throughout adult life. The ontogenic maturation of the intestinal epithelium arises from both a programmed expression of specific genes and epigenetic influences mainly due to epithelial and mesenchymal interactions and hormonal participation. In the present paper we review the structural and functional changes that occur in the amphibian, avian and mammalian intestine during embryonic and/or post-embryonic development. Furthermore, we review the data concerning the mechanisms which control the cytodifferentiation of the intestinal epithelium.

Peptidergic nociceptive axon visualization in whole-mount preparations of cornea and tympanic membrane in rat

A whole-mount preparation is described for visualizing unmyelinated peptide immunoreactive axons in two specialized tissues, thin enough for tracing axons to their terminal knobs. These tissues, the cornea and the mucosal surface of the tympanic membrane, are known to possess specialized nociceptor innervation and can be used for selecting sensory endings labeled by peroxidase reaction product and embedded in plastic for more detailed analysis. Rat calcitonin gene-related peptide antibody proved a particularly robust primary antibody found in a substantial proportion of sensory unmyelinated axons in a variety of fixation and preparative conditions.