Le syndrome de la persistance des dérivés mullèriens: A propos de quatre observations

Persistent mullerian duct syndrome is a relatively rare inherited defect of sexual differentiation characterised by failure of regression of the mullerian ducts in males. In affected individuals, the uterus and tubes are present due to a defect of synthesis or action of antimullerian hormone normally produced by testicular Sertoli cells. The authors report four cases with a mean age of 20 years. All patients were phenotypically normal males, with bilateral cryptorchidism in two cases and unilateral irreducible inguinal mass in the other two cases. The mullerian ducts were removed in two cases and left in place in two cases as they were intimately adherent to the vas deferens. Long-term follow-up was decided due to the risk of malignant transformation of these remnants recently described in literature. According to the authors, the best management of these structures is excision and orchidopexy. In the case of adult infertility with testicular atrophy, gonadectomy and androgen replacement therapy are recommended.     

TheAzotobacter flora of some Czechoslovakian watercourses

The occurrence of Azotobacter in some Szechoslovakian watercourses has been investigated. Several strains belonging to A. chroococcum and A. beijerinckii were isolated from 7 out of 18 samples. A. insignis has been isolated from the flowing water of Lake Machovo at Doksy. This is first report of this strictly aquatic Azotobacter species in Czechoslovakian watercourses. The taxonomy of the genus Azotobacter was discussed against the background of the existing knowledge resulting mainly from other taxonomic techniques than those based on the phenotypically expressed characters.     

Bacterial classification with convolutional neural networks based on different data reduction layers

Abstract

For high accuracy classification of DNA sequences through Convolutional Neural Networks (CNNs), it is essential to use an efficient sequence representation that can accelerate similarity comparison between DNA sequences. In addition, CNN networks can be improved by avoiding the dimensionality problem associated with multi-layer CNN features. This paper presents a new approach for classification of bacterial DNA sequences based on a custom layer. A CNN is used with Frequency Chaos Game Representation (FCGR) of DNA. The FCGR is adopted as a sequence representation method with a suitable choice of the frequency k-lengthen words occurrence in DNA sequences. The DNA sequence is mapped using FCGR that produces an image of a gene sequence. This sequence displays both local and global patterns. A pre-trained CNN is built for image classification. First, the image is converted to feature maps through convolutional layers. This is sometimes followed by a down-sampling operation that reduces the spatial size of the feature map and removes redundant spatial information using the pooling layers. The Random Projection (RP) with an activation function, which carries data with a decent variety with some randomness, is suggested instead of the pooling layers. The feature reduction is achieved while keeping the high accuracy for classifying bacteria into taxonomic levels. The simulation results show that the proposed CNN based on RP has a trade-off between accuracy score and processing time.     

Distribution and flower visitation records of bumblebees in Lebanon (Hymenoptera: Apidae)

Summary

West Palearctic bumblebees are common wildflowers and crop pollinators that are well studied in their central and northern distribution ranges, but fewer information is available on their southern distribution areas. Lebanon falls on the southern limit of their distribution and no published information is available on the local bumblebees. Our study aims to produce a data baseline of the local bumblebee species. In order to do so we grouped available old records of bumblebees in Lebanon with recent author collections and produced preliminary distribution maps. We listed four species: Bombus terrestris, B. argillaceus, B. niveatus vorticosus and B. melanurus. Preliminary distribution shows that Bombus terrestris and B. argillaceus are widespread and have a large foraging range, whereas B. niveatus vorticosus and B. melanurus have a restricted distribution to altitudes above 1800 m with a smaller foraging range. The male cephalic labial gland secretions analysis of local Bombus terrestris specimens provides preliminary evidence that the local subspecies could be Bombus terrestris calabricus. Therefore, we highlight the importance of regulating foreign Bombus terrestris subspecies importation for agriculture purposes, as well as monitoring B. niveatus vorticosus and B. melanurus that are rendered vulnerable by their isolated populations.     

Musculature,nervous system and glands of metasomal abdominal segments of the male of Nomia melanderi Ckll. (Hymenoptera,Apoidea)

Each muscle of the third metasomal segment of the male of Nomia melanderi Ckll. is described in detail. The points of attachment of each muscle are compared with their homologs in other pregenital segments and with their homologs in the female. The function desgnated for each muscle describes its action alone or in conjunction with other muscle(s). New names are given to genital muscles by referring in the name to their points of attachment. Each intratergal muscle has homologous points of attachment in the pregenital segments of both sexes. The median tergo-dorsoplical muscle of the seventh segment and the oblique tergo-dorsoplical muscle of the eighth segment have changed their points of attachment. The intrasternal muscles are modified to suit the needs of courtship and mating, thus they are different from their homologs in the female. The spiracular muscles are well developed in all segments except the eighth, where the sterno-spiracular muscle is absent. The extrinsic genital muscles are derived from the intrasternal muscles of the eighth and ninth segments. The parameral and volsellar muscles are reduced in number. The aedeagal muscles, except the aedeago-phallic, have retained similar points of attachment to those found in primitive Hymenoptera. The topography of the metasomal nervous system is reported in detail by following each nerve and nervule to its termination. The study shows that (at least in Nomia) the criterion of nerve-concentration should not be used alone to indicate evolutionary levels. To accommodate the morphological changes in the terminal segments the Anterior and Posterior Lateral Nerves have migrated to new locations. The pattern of nerve topography (even at the nervule level) is homologous both in the different pregenital segments and between the sexes. The fact that homology does not exist between the external genitalia of the male and the modified ovipositor of the female supports the thesis that the male genital capsule is of phallic rather than prephallic origin. A pair of intersegmental membrane glands located between the seventh and eighth sterna is described. These glands may be the source of a pheromon responsible for gregariousness among “sleeping” males.     

Duration and frequency of non-flow periods affect the abundance and diversity of stream meiofauna

1. Intermittent streams (IS) comprise a large proportion of the drainage network in many parts of the world. The non-flow period of IS are known to impact stream biota because aquatic habitats dry out. However, less well understood are the relative effects of the temporal component of these drying events including their duration and frequency.
2. Here, we characterised effects of temporal component of drying events on abundant and species-rich meiofauna. The effects were assessed in 22 streams in the north-eastern Iberian Peninsula. The duration and frequency of non-flow events was characterized over a period of 250 days prior to sampling the sediment-dwelling meiofauna in riffle zones that completely dried out.
3. Overall, meiofauna abundances were amongst the highest ever reported for streambeds. Most meiofaunal taxa correlated positively with the frequency of drying events and correlated positively with the length of dry periods recorded shortly before sampling, suggesting that the community was able to recover quickly. Tardigrades were the only group to correlate positively with the longest dry periods, suggesting that they had the best resilience capabilities in streams that had experienced the longest droughts.
4. On average, nematodes made up half of the meiofauna. We identified a total of 113 different nematode species. The nematode community was more taxonomically diverse in IS, with a smaller proportion of bacterivores and a higher proportion of fungivore species such as Filenchus vulgaris. Thereby resembling the trophic structure commonly observed in soil ecosystems.
5. Our results show that most meiofauna were positively influenced by drying disturbance, that is being able to quickly recover after them. This suggests outstanding resilience capabilities, and points out meiofaunal organisms as key players for kick-starting stream food webs and functions once flow returns.