Functional study of the pectoral spine stridulation mechanism in different mochokid catfishes.

Mochokidae are able to produce pectoral spine stridulation sounds. During sound production, high speed videos were used to study the pectoral fin movements to identify the mechanisms involved. A call consisted of a series of pulses and occurred during a spine sweep, which was in fact made up of a series of jerky movements. The morphology of the pectoral spines and associated muscles was also observed in different species. The contractions of adductor profundus and superficial adductor allows adduction and abduction movements (sweep) of the spine, respectively. Simultaneously, the contraction of the arrector ventralis or the arrector 3 of the pectoral spine allows the pulling and pressing the ridges of the dorsal process, against the rough lateral face of the spinal fossa. This results in the rubbing of the ridges of the dorsal process, producing sounds. In Synodontis the analogy for sound production would be a brake shoe pressing against a wheel.

Agonistic sounds in the skunk clownfish Amphiprion akallopisos: size-related variation in acoustic features.

Fourteen individuals of the skunk clownfish Amphiprion akallopisos of different sizes and of different sexual status (non-breeder, male or female) were analysed for four acoustic features. Dominant frequency and pulse duration were highly correlated with standard length (r = 0.97), and were not related to sex. Both the dominant frequency and pulse duration were signals conveying information related to the size of the emitter, which implies that these sound characteristics could be useful in assessing size of conspecifics.

Antibodies against glucan, chitin, and Saccharomyces cerevisiae mannan as new biomarkers of Candida albicans infection that complement tests based on C. albicans mannan.

Antibodies against Saccharomyces cerevisiae mannan (ASCA) and antibodies against synthetic disaccharide fragments of glucans (ALCA) and chitin (ACCA) are biomarkers of Crohn's disease (CD). We previously showed that Candida albicans infection generates ASCA. Here, we explored ALCA and ACCA as possible biomarkers of invasive C. albicans infection (ICI). ASCA, ALCA, ACCA, and Candida mannan antigen and antibody detection tests were performed on 69 sera obtained sequentially from 18 patients with ICIs proven by blood culture, 59 sera from CD patients, 47 sera from hospitalized subjects colonized by Candida species (CZ), and 131 sera from healthy controls (HC). ASCA, ALCA, and ACCA levels in CD and ICI patients were significantly different from those in CZ and HC subjects (P<0.0001). In ICI patients, these levels increased as infection developed. Using ASCA, ALCA, ACCA, and Platelia Candida tests, 100% of ICIs were detected, with the kinetics of the antibody response depending on the patient during the time course of infection. A large number of sera presented with more than three positive tests. This is the first evidence that the detection of antibodies against chitin and glucans has diagnostic value in fungal infections and that these tests can complement more specific tests. Future trials are necessary to assess the value of these tests in multiparametric analysis, as well as their pathophysiological relevance.

Functional morphology of the sonic apparatus in Ophidion barbatum (Teleostei, Ophidiidae).

Most soniferous fishes producing sounds with their swimbladder utilize relatively simple mechanisms: contraction and relaxation of a unique pair of sonic muscles cause rapid movements of the swimbladder resulting in sound production. Here we describe the sonic mechanism for Ophidion barbatum, which includes three pairs of sonic muscles, highly transformed vertebral centra and ribs, a neural arch that pivots and a swimbladder whose anterior end is modified into a bony structure, the rocker bone. The ventral and intermediate muscles cause the rocker bone to swivel inward, compressing the swimbladder, and this action is antagonized by the dorsal muscle. Unlike other sonic systems in which the muscle contraction rate determines sound fundamental frequency, we hypothesize that slow contraction of these antagonistic muscles produces a series of cycles of swimbladder vibration.

Geographical variation in sound production in the anemonefish Amphiprion akallopisos.

Because of pelagic-larval dispersal, coral-reef fishes are distributed widely with minimal genetic differentiation between populations. Amphiprion akallopisos, a clownfish that uses sound production to defend its anemone territory, has a wide but disjunct distribution in the Indian Ocean. We compared sounds produced by these fishes from populations in Madagascar and Indonesia, a distance of 6500 km. Differentiation of agonistic calls into distinct types indicates a complexity not previously recorded in fishes' acoustic communication. Moreover, various acoustic parameters, including peak frequency, pulse duration, number of peaks per pulse, differed between the two populations. The geographic comparison is the first to demonstrate 'dialects' in a marine fish species, and these differences in sound parameters suggest genetic divergence between these two populations. These results highlight the possible approach for investigating the role of sounds in fish behaviour in reproductive divergence and speciation.

Anti-Saccharomyces cerevisiae mannan antibodies in inflammatory bowel disease: comparison of different assays and correlation with clinical features.

BACKGROUND: Anti-Saccharomyces cerevisiae mannan antibodies have been proposed as a new serological marker associated with Crohn's disease. However, their clinical value is still unclear; furthermore, a standardization of anti-S. cerevisiae mannan measurements is lacking. AIM: In this study, we aimed to assess the correlation between anti-S. cerevisiae mannan detection and specific clinical features in Crohn's disease and ulcerative colitis. Moreover, we tested the concordance of four different anti-S. cerevisiae mannan assays. MATERIALS AND METHODS: Serum samples from 196 patients with Crohn's disease, 197 patients with ulcerative colitis and 100 unrelated healthy controls were tested for anti-S. cerevisiae mannan with a standard enzyme-linked immunosorbent assay method (Lille) by one of the authors (VP). Subsequently, 60 randomly selected serum samples (27 Crohn's disease, 28 ulcerative colitis and five healthy controls) were tested for anti-S. cerevisiae mannan with three different commercial kits. RESULTS: With the Lille assay, anti-S. cerevisiae mannan were detected in 100 of 196 patients with Crohn's disease (51%; P < 0.0001 vs. controls), 32 of 197 patients with ulcerative colitis (16%; P < 0.02 vs. controls), and six of 100 controls (6%). No correlation between presence of anti-S. cerevisiae mannan and specific clinical features was found in both ulcerative colitis and Crohn's disease patients. The percentages of anti-S. cerevisiae mannan detected with four different assays ranged from 28 (Bouty) up to 43% (Inova), but these differences did not reach statistical significance. The concordance rate of anti-S. cerevisiae mannan detection in the four assays was very low (11 concordant results of 60 samples, 18.3%) (k = 0.15). No improvement of the concordance rate was obtained by modifying the suggested cut-off values (k = 0.20). CONCLUSION: In this study, we confirm that anti-S. cerevisiae mannan are significantly more frequent in Crohn's disease patients compared with ulcerative colitis patients (P < 0.0001) and controls. However, no correlation with clinical features was found in both ulcerative colitis and Crohn's disease. The low prevalence of anti-S. cerevisiae mannan, at least in our population, and the low concordance rate between different assays, makes the clinical role of this marker questionable.

Characterization of the primary sonic muscles in Carapus acus (Carapidae): a multidisciplinary approach.

Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic muscles and compare them with epaxial muscles in Carapus acus. Sonic fibres are thicker than red and thinner than white epaxial fibres, and sonic fibres and myofibrils exhibit an unusual helicoidal organization: the myofibrils of the centre are in a straight line whereas they are more and more twisted towards the periphery. Sonic muscles have both features of red (numerous mitochondria, high glycogen content) and white (alkali-stable ATPase) fibres. They differ also in the isoforms of the light chain (LC3) and heavy chain (HC), in having T tubules at both the Z-line and the A-I junction and in a unique parvalbumin isoform (PAI) that may aid relaxation. All these features lead to the expression of two assumptions about sound generation: the sonic muscle should be able to perform fast and powerful contractions that provoke the forward movement of the forepart of the swim bladder and the stretching and "flapping" of the swim bladder fenestra; the helicoidal organization allows progressive drawing of the swim bladder fenestra which emits a sound when rapidly released in a spring-like manner.

Expression of myofibrillar proteins and parvalbumin isoforms during the development of a flatfish, the common sole Solea solea: comparison with the turbot Scophthalmus maximus.

Developmental changes in myofibrillar protein and parvalbumin isoform composition were investigated in the myotomal muscle of the flatfish Solea solea, characterized by a very brief metamorphic stage. Results were compared with previously obtained data on another pleuronectiform teleost, the turbot (Scophthalmus maximus), displaying prolonged metamorphosis. Electrophoretically measurable changes in myofibrillar proteins and parvalbumins were detected late in the sole, after completion of metamorphosis. In the course of development, muscles showed the usual sequential synthesis of isoforms of the myofibrillar proteins myosin light chain LC2, troponin-T, and troponin-I. An adult parvalbumin isoform (PA III) was found to predominate during sole growth. The two flatfish were characterized by highly species-specific parvalbumin isoforms. Compared with turbot, the profiles of the myofibrillar subunits and parvalbumin isoforms varied little in the course of sole development. The early appearance of adult traits might be correlated with the brevity of metamorphosis of this fish.

Sound-producing mechanisms and recordings in Carapini species (Teleostei, Pisces).

Carapus boraborensis, C. homei and Encheliophis gracilis are three species of Carapidae that display the ability to penetrate and reside in the holothurian Bohadschia argus. This study describes both the particular morphology of the sound-producing structures and, for the first time, the sounds produced by each species. The study of the structures composing the sound-producing system seems to indicate that the action made by the primary sonic muscles (i.e. the pulling and releasing of the front of the swim bladder) might be responsible for the sound emissions of these three species by provoking a vibration of a thinner zone in front of the swim bladder (swimbladder fenestra). The sounds were only emitted and recorded when several individuals of the same species were inside the same sea cucumber. They were composed of serially repeated knocks and were heard as drum beats or drum rolls. Their specific differences were mainly defined as variations in the timing or grouping of the knocking sounds. The recordings of these sound productions demonstrate a vocal ability for the three species, linked with the presence of particular organs associated with sound production. Moreover, the ecological significance of the sounds and of the sound apparatus system is discussed.

Immunological study of muscle parvalbumin isotypes in three African catfish during development.

Eleven parvalbumin isotypes expressed during the development of clariids Heterobranchus longifilis and Clarias gariepinus and claroteid Chrysichthys auratus were purified and electrophoresed on sodium-dodecyl-sulfate polyacrylamide gels. Immunochemical cross-reactions among these proteins were investigated by immunoblotting, using purified antibodies raised against three isotypes chosen at different stages of fish development. Antibodies raised against H. longifilis PA I (larval-juvenile isotype) and against C. gariepinus PA IIIa (juvenile-adult isotype) cross-reacted to a rather similar extent despite a weaker cross-reaction of anti-PA IIIa with larval-juvenile isotypes. On the other hand, antibodies raised against H. longifilis PA IV (an exclusively adult isotype) recognized markedly only H. longifilis PA IV and C. gariepinus PA IIIb. These two adult isotypes most likely belong to the alpha lineage, and all the others to the beta lineage. These results show that parvalbumin isotypes synthesized at different stages of fish growth differ structurally, and that the most marked difference is between larval-juvenile and adult clariid isotypes.

Genetic diversity of african and worldwide strains of ralstonia solanacearum as determined by PCR-restriction fragment length polymorphism analysis of the hrp gene region

The genetic diversity among a worldwide collection of 120 strains of Ralstonia solanacearum was assessed by restriction fragment length polymorphism (RFLP) analysis of amplified fragments from the hrp gene region. Five amplified fragments appeared to be specific to R. solanacearum. Fifteen different profiles were identified among the 120 bacterial strains, and a hierarchical cluster analysis distributed them into eight clusters. Each cluster included strains belonging to a single biovar, except for strains of biovars 3 and 4, which could not be separated. However, the biovar 1 strains showed rather extensive diversity since they were distributed into five clusters whereas the biovar 2 and the biovar 3 and 4 strains were gathered into one and two clusters, respectively. PCR-RFLP analysis of the hrp gene region confirmed the results of previous studies which split the species into an "Americanum" division including biovar 1 and 2 strains and an "Asiaticum" division including biovar 3 and 4 strains. However, the present study showed that most of the biovar 1 strains, originating from African countries (Reunion Island, Madagascar, Zimbabwe, and Angola) and being included in a separate cluster, belong to the "Asiaticum" rather than to the "Americanum" division. These African strains could thus have evolved separately from other biovar 1 strains originating from the Americas.

Distinctive anatomical features of the branchial basket in four carapidae species (ophidiiformi, paracanthopterygii).

The present study focuses on the branchial basket in four Carapidae species: Carapus acus, Encheliophis boraborensis, Encheliophis homei and Encheliophis gracilis. The aim is to highlight the skeletal and muscular features of the branchial basket, especially those that are believed to be related to their way of life and/or to be linked to the presence of primary sound-producing muscles. The space occupied by the primary sound-producing muscles between the neurocranium and the branchial basket gives rise to distinctive skeletal and muscular features. They prevent the 1st pharyngobranchials from becoming attached to the neurocranium in the normal way. These do not seem to play any role in the suspension of the upper pharyngeal jaws, as it is usually the case in teleosteans. The 1st epibranchials are separated from the 2nd pharyngobranchials. Ossified interarcual elements jointed to the 2nd pharyngobranchials and 1st epibranchials are found in the position usually occupied by the latter. The presence of primary sound-producing muscles gives rise to the need for the reorganisation of the musculature which is seen in particular with regards to the levatores branchiales. These are not found on the neurocranium but on the hyomandibular. The general skeletal and muscular data and the observations of the stomach contents suggest that the action of the branchial basket is restricted to carrying food in Carapus acus, Encheliophis boraborensis and Encheliophis homei, whereas it could also play a role in the work of cutting up soft food in Encheliophis gracilis.

Isoform distribution of parvalbumins and of some myofibrillar proteins in adult and developing Chrysichthys auratus (Geoffroy St. Hilaire, 1808) (Pisces, Claroteidae).

Polyacrylamide gel electrophoresis was used to analyse the distribution of parvalbumin, myosin light chain, and troponin I isoforms in white muscles of larval, juvenile, and adult Chrysichthys auratus (catfish, siluriforms) and to study the kinetics of their synthesis. Parvalbumin isoform PA II was first detected from day 5 post-hatching and was the main "larval" isoform in this species. PA III appeared at the beginning of the juvenile stage but always remained the minor isoform, even in adult fish. Young mature specimens (approximately 12 cm long) displayed the highest total parvalbumin content. Adult-type myosin light chains were detected from day 8. Densitometric analysis confirmed the light-chain distribution typical of fish muscles, with a relatively high amount of LC3 and a low amount of LC1. We evidenced a "larval" form of troponin-I and its progressive replacement by an "adult" form.

Biochemical attempt to characterize thirteen cichlid species by their muscular parvalbumins.

This paper shows the usefulness of polyacrylamide gel electrophoresis (PAGE) separation of a few well-characterized muscle proteins, the parvalbumins, in the systematic study of 13 cichlid species. The separation of the isoforms of these abundant, quite species-specific fish parvalbumins is fast, easy, and requires but small quantities of muscle material. Used alone, this technique suggests hypotheses for species classification. In conjunction with morphological analysis, it makes it possible to confirm or invalidate doubts about the determination.

Myosin, parvalbumin and myofibril expression in barbel (Barbus barbus L.) lateral white muscle during development.

Histo- and immunohistochemical techniques have recently been used to study the fibre type and myosin expression in fish muscle during development. In the present work, embryonic, larval and adult myosin isozymes (heavy and light chains) and parvalbumin isotypes were analyzed, from fertization to the adult stage, by polyacrylamide gel electrophoresis of barbel (Barbus barbus L.) trunk muscle extracts. The examined myosins display the sequential transitions from embryonic to larval and adult forms characteristic of higher vertebrates. They are characterized by specific heavy chains but their light chains differ only by the LC1/LC3 stoichiometry with LC3 exceeding LC1 after 10 days. Sarcoplasmic parvalbumins show considerable and unforeseen developmental transitions in their isotype distribution: the PA II isotype first appears after hatching and becomes the predominant form until the length reaches about 6 cm. One month after hatching, the amount of PA II then decreases and the synthesis of PA III and IV further increases to reach the typical adult pattern at a size of 18 cm. These observations show that the distribution of parvalbumin isotypes reflects the stage of development. It suggests a specific role for each isotype in relation to muscle activity. Microscopy illustrates the progressive development of somites, muscles cells, and myofibrils, which accelerates at hatching when movements increase.

Myosin heavy chain isoforms in white, red and ventricle muscles of barbel (Barbus barbus L.).

1. Actomyosin extracts of trunk, heart, and head muscles from barbel (Barbus barbus L.) were analyzed by SDS-polyacrylamide gel electrophoresis to study their myosin heavy chain composition. 2. Four heavy chain isoforms were found: trunk white, trunk red, and ventricle muscles yielded one heavy chain typical of the muscle type; head muscles devoid of red fibers displayed two heavy chain isoforms, the slow migrating one corresponding to the trunk white muscle type. 3. The electrophoretic mobility of red and ventricle myosin heavy chains related to that of white isoforms appeared highly modified by the glycerol content of the gels.

Use of the biochemical analysis of muscle proteins to help the classification of polychromic individuals of the genus Symphodus.

Among Labrid fishes (Wrasses), polychromy is very frequent. Indeed, a few species of Symphodus show individuals with a peculiar colouration. On one hand, electrophoretic analysis of muscular proteins (myosin and parvalbumins) reveals no differences between the normal individuals and the coloured morphs of the three species. On the other hand, these analyses display disparities between fishes of the two subgenus (Crenilabrus and Symphodus). Biochemical characters seem to have evolved in the same way that morphological and behavioural ones: the subspecies based only on differences in colouration are not confirmed but the differences between subgenus are revealed.

Relationships between the taste buds and the peculiar structures and movements of the first dorsal fin in Motella mustela (L.) (Pisces, Gadiformes).

The needs of the chemoreception function alone do not explain the anatomical peculiarities of the first dorsal fin of M. mustela. These ones are surely in relation with other necessities as those of the protection of the structure.

Oxidation of reduced cytochrome c by hydrogen peroxide. Implications for superoxide assays.

Hydrogen peroxide, formed directly or as a product of superoxide dismutation, can oxidize ferrocytochrome c at rates comparable to those at which ferricytochrome c is reduced by superoxide. This reoxidation can significantly affect estimates of rates and amounts of superoxide production using absorbance changes for cytochrome c at 550 nm as the assay. The oxidation can be inhibited by catalase.