Alcaloïdes chez les capparidaceae

Alkaloids were isolated from leaves of 33 of 36 species and l-stachydrine and l-3-hydroxystachydrine were the major components present. These alkaloids characterize the family Capparidaceae in the same way as do the glucosinolates.     

Les tissus élaborateurs d'hormones stéroïdes chez les amphibiens urodèles

Résumé Les cellules du tissu glandulaire du testicule et de la glande interrénale de pleurodèle montrent les caractères généralement observés dans les cellules stéroïdogènes. Des différences existent entre les deux tissus. Le reticulum endoplasmique du tissu glandulaire est très développé et présent dans toutes les cellules qui sont d'aspect homogène. Au contraire, le tissu interrénal montre deux aspects cellulaires différents. Le premier se caractérise par un reticulum endoplasmique lisse relativement peu développé par rapport au tissu glandulaire, par des mitochondries petites et nombreuses, enfin par des liposomes denses et petits. Le deuxième aspect au contraire, se distingue par le petit nombre de mitochondries souvent géantes et à crêtes plus fréquemment organisées en faisceaux, par des liposomes nombreux de grandes dimensions et peu denses aux électrons.Le tissu glandulaire est très peu touché par l'hypophysectomie. Le reticulum persiste plusieurs mois comme d'ailleurs l'activité 5-3 -hydroxystéroïde deshydrogénase. Dans le tissu interrénal, la proportion des cellules d'aspects différents varie au profit des cellules à lipides abondants et à grandes mitochondries. L'activité 5-3 -hydroxystéroïde deshydrogénase est longtemps décelable.Le rôle du reticulum endoplasmique du tissu glandulaire est discuté en fonction des observations réalisées dans d'autres cellules stéroïdogènes à reticulum abondant. La signification des deux aspects cellulaires observés dans l'interrénale est discutée en relation avec les résultats expérimentaux obtenus en particulier chez le rat.Cette étude révèle que les critères d'activité d'une cellule stéroïdogène sont délicats à établir et doivent être différents d'un tissu à l'autre.

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Tissues secreting steroid hormones in urodele amphibians

Summary The fine structure of testis glandular tissue and interrenal gland cells of Pleurodeles shows the general features observed in other steroïdogenic cells. Certain differences exist between the two tissues. The agranular endoplasmic reticulum of the glandular tissue cells is well developed and present in all cells of similar appearance. On the contrary, the interrenal tissue cells show two different features. The first is characterised by a poorly developed smooth endoplasmic reticulum, compared with that of the glandular tissue, by small and numerous mitochondria, and finally by small electron dense lipid droplets. The second feature is the small number of mitochondria often giant and with fascicles of straight tubular cristae and numerous large lipid droplets of low electron density.The effect of hypophysectomy on the glandular tissue cells seem very slight. The endoplasmic reticulum and the 5-3 -hydroxysteroid dehydrogenase activity persists for several months. In the interrenal tissue, the proportions of the two different cellular features are modified. Cells rich in lipids and with large mitochondria are more abundant. It is possible to demonstrate a 5-3 -hydroxysteroid dehydrogenase activity for a long time after hypophysectomy. The functional significance of the agranular endoplasmic reticulum is discussed in relation to some other observations on different steroidogenic cells with a well developed agranular endoplasmic reticulum. The significance of the two cellular features observed in the interrenal gland is discussed in connection with experimental data obtained in the frog and the rat.This study shows that it is difficult to define criteria of cellular activity, which probably differ from one tissue to another.

Equipe de Recherche associée au C. N. R. S. Cytologie Ultrastructurale n 129.     

Liste des cyclopoïdes gnathostomes (Crustacés copépodes) des îles Britanniques et de l'Irlande

Résumé La liste de Cyclopoïdes gnathostomes donnée comprend 58 formes pour la Grande-Bretagne (Angleterre 56, Ecosse 40) et 38 pour l'Irlande.A titre de comparaison on peut mentionner qu'on en connaît actuellement 56 en France et 37 dans les Pays-Bas.Quelques remarques ont été faites sur des questions de nomenclature et concernant certaines espèces.     

Apoptose et ségrégation méiotique dans les spermatozoïdes d'hommes porteurs de translocations

Men with a chromosomal translocation produce a significant percentage of unbalanced spermatozoa. In order to determine a correlation between chromosomal anomalies and apoptosis in human sperm, we analysed DNA fragmentation and meiotic segregation in sperm from men with a (13;14) Robertsonian translocation. We studied sperm from 12 (13;14) translocation carriers and 9 proven fertile men with a normal karyotype. Meiotic segregation of chromosomes 13 and 14 was analysed using dual-colour fluorescencein situ hybridization with locus-specific probes for chromosomes 13 and 14. Apoptosis in spermatozoa was measured byin situ TUNEL assay. The meiotic segregation study showed a significantly increased frequency of unbalanced spermatozoa for chromosomes 13 and 14 in (13;14) carriers (15.9%) compared to the control population (1.3%) (p=0.00016). The study of apoptosis showed an increase of DNA fragmentation in (13;14) carriers (34.9%) compared to the control population (13.8%) (p=0.0036). This increased apoptosis was observed in spermatozoa presenting an increase of unbalanced chromosomal anomalies concerning chromosomes 13 and 14, but with a predominance of balanced spermatozoa compared to the theoretical risk of meiotic segregation. These results suggest that apoptosis could be involved as a regulatory mechanism to eliminate unbalanced chromosomal spermatozoa in men with a (13;14) Robertsonian translocation.     

Hyperparasitisme facultatif de parasitoïdes en cours de développement par les femelles des ectoparasitoïdes Eupelmus vuilleti et Eupelmus orientalis Craw

In a community of three ectoparasitoids, Dinarmus basalis, Eupelmus vuilleti and E. orientalis, the host Callosobruchus maculatus parasitised 48 h before by D. basalis, is accepted by E. vuilleti females after they have eliminated the eggs and neonatal larvae of D. basalis. This ovicidal and larvicidal behaviour enables E. vuilleti to develop on C. maculatus instead of D. basalis. E. vuilleti females are able to parasitise the L5 larval stage and the pupa of D. basalis: their larvae therefore feed at the expense of the developing parasitoid. This trophic level is that of hyperparasitism. However, E. vuilleti females rarely practise hyperparasitism on their own L5 larvae and on those of E. orientalis. This behaviour reveals a high behavioural plasticity enabled by intra- and interspecific recognition of parasitoids used as hosts. Hyperparasitism activity in E. orientalis females is higher than that in E. vuilleti females since they hyperparasitise host parasitoids more frequently without preferential species choice. However, E. vuilleti seems to be free from competitive pressure with E. orientalis, as the former penetrates deeply into a grain store contaminated with C. maculatus in contrast to E. orientalis females, which remain on the surface from where they escaped.     

Distribution et activités des alcaloïdes défensifs des Coccinellidae

From a survey of 30 species and varieties of ladybugs the presence of alkaloids appears to be correlated with the existence of aposematic colour and not with being carnivorous or phytophagous. The alkaloids described until now all belong to the Coccinellini and are closely related, but other types of bases have been detected in some genera. The observed distributions are in agreement with the modern taxonomy of the family.Ladybug alkaloids constitute an effective defence against ants, Myrmica rubra, and quails, Coturnix coturnix, but all the beetles containing alkaloids do not possess the same degree of protection. Individual quail react differently towards moderately protected species.The bioassay used for the first isolation of coccinelin is described. The repulsive activities of aqueous solutions of coccinellin and convergin towards ants have been compared.     

Recherches sur les mouvements des amibocytes des Invertébrés

Resumé Dans la première partie de ce travail, nous avons montré que, contrairement à la conception deFauré-Fremiet, les mouvements que présentent les amibocytes des Invertébrés à l'état actif ne peuvent s'expliquer par le seul jeu des forces de tension superficielle. Ces forces, si elles interviennent das le mécanisme du mouvement, ne peuvent en expliquer l'origine; l'amibocyte, tel qu'il est constitué, est un système inerte, incapable de se mouvoir sans apport d'énergie.Les faits exposés dans la seconde partie montrent qu'on peut dissocier physiologiquement le granuloplasme nucléé de l'hyaloplasme. Des coelamibocytes d:'Allobophora longa soumis à l'action de toxiques ou d'anesthésiques peuvent présenter des mouvements de leur hyaloplasme longtemps après que le granuloplasme nucléé a cessé toute activité fonctionnelle (mort ou anesthésie). Ces substances inhibent les activités complexes du granuloplasme, probablement les activités diastasiques, tout en conservant intactes les activités d'ordre plus simple qui président aux mouvements de l'hyaloplasme.     

Recherches sur les efflorescences des phéophycées

Resume L'analyse radiocristallographique de diverses Phéophycées a révélé la nature des substances insolubilisées a l'intérieur du thalle et formant des elorescences au cours de la dessiccation.Le D-mannitol cristallise essentiellement sous la forme monoclinique, les variétés et ß orthorhombiques apparaissent plus rarement toujours en faibles quantités.L'examen röntgénographique et les analyses quantitatives montrent que les chlorures de sodium et de potassium se déposent à la surface en proportions qui reflètent les variations de composition du thalle. Les valeurs du rapport Na⁺/K⁺ sont caractéristiques des diverses familles.

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Summary An X-Rays analysis of various Phaeophyceae has revealed the nature of substances inside the thallus becoming insoluble and efflorescing during drying.D-Mannitol cristallizes essentially in monoclinic form, and ß orthorhombic varieties appear less frequently.Röntgenographic examination and quantitative analysis show sodium and potassium chlorides forming a surface deposit in proportions correlated with the variations of the chemical composition of the thallus. The values of the ratio Na⁺/K⁺ are typical of the various algal families.

     

Distances éntre l'homme et les singes anthropoïdes basées sur la mobilité électrophorétique des protéines et enzymes

Electrophoretic mobilities of ten homologous serum proteins and enzymes in Man and anthropoid apes led to estimations of the genetic distances between five species (Homo, Pan, Gorilla, Pongo and Symphalangus). The separation of the Symphalangus (Siamang) lineage from that leading to the great apes and Man is obvious. Less evident is the cluster containing only humans and chimpanzees, and also the fact that orang-utans are placed closer to Man than gorillas.     

Spermatozoïdes,environnement et prévention

Over the last fivty years, the risk factors for infertility have increased substantially, particularly those due to the environment. Spermatogenesis and spermatozoa can be affected by physical (ionizing radiation microwaves, heat, cryopreservation) or chemical agents (antimitotics drugs, antibiotics, tranquillizers, insecticides, pesticides, industrial solvants, some heavy metals, alcohol, cannabis etc.). Some natural factors, as stress or paternal age (ageing or very youthful age relatively to about thirty) also seems to affect spermatogenesis and, particularly, the age can be joined with the previous ones. On the whole, these factors are able to decrease the male fertility through some changes about the concentration, the motility or the morphology of spermatozoa and so it is possible to describe populations subject to the risk. Moreover, these spermatogenetic changes can lead abnormalities in progeny. For instance, some antimitotic drugs as cyclophosphamide, when administrated to the male rat, lead malformations or functional anomalies as behavioral troubles. The industrial solvents lead a decrease of the birth weight and the cannabis leads an increase of the ante-or post-natal death. Moreover, the change of the paternal spermatogenesis caused by cannabis can be found again in the male progeny. The problem is similar with the lead, the benzodiazepines and the alcohol. Concerning the physical factors, some authors have shown that the children born from radiation exposed fathers presented an increase of the probability of leukemia. In animal, the postimplantation loss is increased when the father is irradiated or subjected to heat before mating. Finally, the paternal ageing is responsible for new dominant autosomic mutations. Moreover, in animal and man, paternal ageing and, in man, very youthful age, also seems responsible for a gradual lowering in the level of progency cerebral functions. On the whole, these data should lead to an preventive attitude which would be more effective before about thirty years of age than after this period.     

Génotoxicité des chimiothérapies et radiothérapies: Quelles sont les conséquences pour le spermatozoïde humain?

The prognosis of cancer in young men of childbearing potential has been considerably improved over recent decades as a result of therapeutic progress. Chemotherapy and radiotherapy have well known effects on spermatogenesis. Apart from quantitative and qualitative impairment of spermatogenesis, animal studies have also demonstrated nuclear lesions (aneuploidy, presence of adducts, DNA fragmentation, etc.) and sometimes lesions affecting the F1 and F2 generations. Chromosomal studies of human spermatozoa after radiotherapy have demonstrated an increased frequency of chromosomal anomalies. The first studies concerning the effects of chemotherapy used the heterospecific fertilization technique to demonstrate spermatozoal chromosomal anomalies. More recently, thefluorescence in situ hybridization (FISH) technique has been used to study several chromosomes on a large number of spermatozoa. The results of various studies based on small sample sizes vary as a function of the therapeutic protocol administered and the time of sperm collection in relation to the end of treatment. We studied 5 patients who provided a semen sample 6 to 17 months after completing the BOE chemotherapy protocol (Bleomycin, Etoposide, Cisplatin). We demonstrated an increased rate of aneuploid and diploid spermatozoa. The results of our study and those reported by R. Martin et al. [45, 47] suggest the possibility of a transient effect of chemotherapy on gamete chromosomes. Other studies, conducted in the context of Hodgkin’s disease, have demonstrated the transient nature of the aneuploidy effect. Apart from the harmful action on chromosomes, treatments could also damage spermatozoal DNA. Studies conducted on larger sample sizes and using other methods of analysis therefore appear to be essential. In the meantime, it appears preferable to systematically propose semen cryopreservation before treatment and to provide very cautious advice to patients desiring a pregnancy soon after completion of treatment.     

Données récentes sur la maturation des spermatozoïdes dans l'épididyme humain

Au cours de leur transit épididymaire, les spermatozo?des rencontrent un environnement varié, au regard des protéines avec lesquelles ils rentrent en contract. Dans la partie proximale de l'épididyme, ils sont soumis à l'action d'enzymes, et exposés à des protéines susceptibles de modifier les membranes. Dans la partie moyenne prédomine une autre catégorie de protéines et d'enzymes; celles associées au transport de stérols pourraient modifier les membranes spermatiques afin de permettre l'ancrage de protéines de liaison à la zone pellucide: P 34H et CD52. Dans la partie distale les spermatozo?des rencontrent des activités croissantes d'enzymes lytiques, des protéines impliquées à la fois dans la liaison à la zone pellucidé et la fusion ovocytaire, l'antigène de maturation CD 52, une activité anti-microbienne, et enfin des agents décapacitants qui facilitent leur survie avant l'éjaculation. L'adhérence des protéines aux différents domaines membranaires (comme la région antérieure ou le segment équatorial de l'acrosome) peut dépendre de la nature de la protéine, de la composition lipidique de la région membranaire concernée, et de l'environnement ionique dans la lumière épididymaire. La localisation des protéines sur le spermatozo?de, qu'il soit à acrosome intact (membrane acrosomique) ou acrosome-réagi (segment équatorial) pourra dicter leur r?le, concernant par exemple la fixation à la zona (P 34H), ou la liaison à l'ovocyte (gp 20). Les protéines comme les membranes peuvent être modifiées durant le transit épididymaire par des enzymes qui peuvent ajouter ou retirer des sucres et des peptides de la surface spermatique.     

Anticorps anti-spermatozoïdes: techniques de dépistage et interprétation des résultats

Since the first publication on the detection of sperm-agglutinating antibodies in infertile men, multiple assays have been described. The most useful tests are able to detect antibodies bound to the sperm membrane of motile spermatozoa. The immunobeads test (IBT) is considered to be the most advantageous in terms of its sensitivity, the low incidence of false-positive results, and its ability to localize antibodies of different immunoglobulin classes on the sperm surface. The IBT assay can be used in parallel with the mixed antiglobulin reaction (MAR), to detect sperm-associated antibodies in the ejaculates of infertile men, the most rational way to test for antisperm antibodies (ASA) in males. In view of the high level of agreement between the two assays, MAR, the easier of the two, may be used as a first step in the detection of these antibodies. A positive MAR must be confirmed by IBT, as this assay is more specific for the detection of IgA antibodies. The clinical significance of sperm-associated antibodies is usually established according to the proportion of motile spermatozoa coated with immunobeads, its class and its localization on the sperm surface. However, binding of immunobeads does not provide any information about the antigens against which the antibodies are directed. As the functional effects of sperm-associated antibodies may vary as a function of their antigenic specificities, other assays, using purified fertilization related antigens, are necessary to establish, for each individual, the specific impact of the antibodies on the fertilization process. The indirect IBT assay has recently become the most widely used test to detect the various classes of ASA in serum and cervical mucus of infertile women and in the serum and seminal fluid of infertile men, in combination with the direct assay described above. However, in most laboratories, it is performed with only one dilution of the biological fluid tested, usually a low dilution, so that antibody levels of no significance for fertility could be detected. This may explain a recente debate (Human Reprod, 1999) on the significance of ASA as a cause of infertility. At present, and in the absence of standardized assays able to identify the antigens involved in each individual immune reaction, antibody assays, as detected by the IBT assay, in the serum and/or genital secretions of infertile subjects might provide useful clinical guidance.     

La sélection des spermatozoïdes à fort grossissement permet-elle une diminution de la fréquence des aneuploïdies spermatiques?

Severe male infertility concerns two categories of men. Men with abnormal karyotype, who represent 2 to 14% of infertile men and who can produce sperm cells carrying unbalanced chromosomes related to the patients initial chromosomal reorganization inducing a variable risk of transmission of the abnormality to their conceptus. The second category is men with a normal karyotype but an increased rate of spermatic aneuploidy in a context of severe oligo- and/or asthenozoospermia and men from couples in implantation failure. ICSI is the standard Assisted Medical Reproductive technique for most of these 2 categories despite the obvious increased chromosomal risk. This raises the question of how to morphologically identify sperm cells with abnormal chromosome content during ICSI ? Unfortunately, no relationship has yet been found between sperm morphology in the ICSI sperm fraction (×200) and their chromosome content. Nevertheless, since the end of the 1990s, Bartoov’s team has developed MSOME (Motile Sperm Organelle Morphology Examination) consisting of high-power examination of sperm cells up to × 12,250. This technique was indicated for cases of repeated ICSI failures and appeared to increase pregnancy rates. But was this improvement due to better selection of the chromosomal content of sperm cells to be injected? The present study addressed this question by estimating the value of MSOME in the selection of euploid sperm cells in 2 groups of patients known to have an increased rate of sperm aneuploidy. Group 1 was composed of 2 patients with normal karyotype who presented a macrocephalic sperm syndrome with more than 99% of aneuploid sperm. Group 2 was composed of 11 patients with abnormal karyotype: 6 patients with reciprocal translocation and 5 patients with Robertsonian translocation. The purpose of this study was to compare spermatozoa aneuploidy rates in fresh semen, to those obtained after ICSI selection (×200) and MSOME selection (×6000). Three specific steps of the protocol were (1) all sperm cells selected in MSOME were “top sperm cells“ (2) fixation of selected sperm cell (average loss of 15% during FISH washes) (3) FISH results were validated by two different examiners. FISH analysis of X, Y and 18 chromosomes showed that MSOME eliminates polyploid and diploid sperm cells in patients with macrocephalic sperm syndrome, but the 6 sperm cells selected were all haploid and aneuploid. FISH analysis of X, Y and 18 chromosomes of all other patients did not show any influence of the selection method on the aneuploidy rate. For the 5 subjects with a Robertsonian translocation, the global results of FISH analysis paradoxically showed a significant decrease of the euploidy rate in MSOME selection. The global results of FISH analysis for the 6 patients with mutual reciprocal translocations, showed that the various mutual translocations were not modified between whole sperm and the 2 selection methods. On the other hand, a significant decrease of adjacent 1 and 2 segregation frequency was observed between whole sperm and MSOME selection, associated with a significant increase of 3:1 segregation frequency suggesting that the segregations which modify the structure of chromosomes, for example adjacent 1 and 2 segregations, would induce visible morphological modifications selected by MSOME. We hypothesized that the efficacy of spermatic apoptosis could be modulated by morphology but also by the chromosome contents of the sperm cell. In conclusion, MSOME does not provide any guarantee of the normal chromosome contents of the TOP selected sperm cell. However, these results obtained in a small series of patients suggest that MSOME can eliminate some chromosome abnormalities (adj1 and 2) which would alter sperm nuclear structures.     

Principes de préparation et de congélation des spermatozoïdes testiculaires humains

The advantages and feasibility of human testicular spermatozoa cryoconservation for intracytoplasmic sperm injection (ICSI) have now been clearly demonstrated. However, the freezing protocol is based on empirical knowledge obtained from freezing of ejaculated spermatozoa. Testicular spermatozoa may not be fully mature gametes and may also be retrieved in only limited quantities. Little research has been conducted to determine whether they have the same cryobiological requirements as ejaculated spermatozoa. A better understanding of their cryobiological features and assessment of possible subcellular changes after thawing would help to optimize testicular preparations for cryopreservation (whole biopsies, seminiferous tubules, shredded suspension, single spermatozoa, etc.), freezing-thawing procedure, freezing media, and storage. Finally, there is a growing need for welldefined criteria (nuclear quality, etc.) to evaluate the tolerance of testicular spermatozoa to freezing-thawing procedure for ICSI     

Morphologie des spermatozoïdes

Spermatozoa morphology is one of the qualitative characteristics of spermatogenesis. However, because of both the variations in the definition of normal morphology and the existence of different kinds of sperm abnormalities as well as the use of various techniques of morphology assessment, such a parameter is poorly used in usual laboratory work. Morphological sperm anomalies can be from testicular or post-testicular origines, while the latter is still unproved. The causes of such anomalies are either from genetic origines, but in these cases any spermatozoa demonstrate this anomaly, or due to an endogenous factor with varicocele the most usually quoted but unproved pathology, But exogenous factors, either chemical such as drugs and pesticides or physical such as heat, are also responsible for morphological sperm anomalies. Analysis of sperm morphology is indicative of both the testicular health status (in cases of occupational exposure to chemical or physical toxics) and the fertility potential since morphology is correlated to sperm motility and involved in fertilization through the acrosome reaction.