Antennae: the strongest magnetic part of the migratory ant

Pachycondyla marginata (P.m.), a migratory and termitophageous ant, hunting only the termite species Neocapritermes opacus, migrates significantly oriented 13 degrees with respect to the magnetic North-South axis. Results of hysteresis curves at room temperature of four Pachycondyla marginata heads, thorax, pairs of antennae and abdomens, oriented parallel to the magnetic field, indicate that the antennae give the strongest saturation magnetization, suggesting this sensory organ as being also a magnetic sensory organ. The total saturation magnetization in a whole P.m. is composed by 42 +/- 3%, 24 +/- 3%, 19 +/- 3% and 15 +/- 3% of antennae, head, thorax and abdomen contributions, respectively. The abdomen hysteresis curve presents a wasp-waisted loop with Hcr/Hc of 4.75, characteristic of mixed magnetic systems.     

Terpenoids dominate the bouquet of volatile organic compounds produced by <Emphasis Type="Italic">Passiflora edulis</Emphasis> in response to herbivory by <Emphasis Type="Italic">Heliconius erato phyllis</Emphasis> (Lepidoptera: Nymphalidae)

In response to injury, plants produce volatile organic compounds (VOCs) that usually differ depending on the type of damage they have suffered (e.g., mechanical damage, herbivory, and oviposition). The objectives of this study were to identify and compare the bouquet of volatiles emitted by passion vine plants (Passiflora edulis) after injury caused by mechanical damage (MD), herbivory (HB), and oviposition (OV) by the lepidopteran, Heliconius erato phyllis. Following injury, extracts of plant emissions were collected from each treatment every 24 h for three days and were analyzed by GC and GC/MS. Results show that plants emitted 12 volatiles before and after damage, namely terpenoids, ketones, and aldehydes. Although no significant differences were detected between the three treatments individually, if the entire bouquet of volatiles is analyzed, samples collected at 24 h were different from samples collected at 48 and 72 h. However, terpenoid emission increased significantly in HB plants after 24 h. HB plants emitted approximately 6300, 50, 46, 11, 6, and 3.6 times more (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), (E)-β-ocimene, (Z)-β-farnesene, (E)-β-caryophyllene, and farnesane, respectively, compared to control plants. OV plants displayed a peak of emission of (E)-β-ocimene after 72 h, which distinguished them from HB plants. MD plants showed a general increase of VOCs versus undamaged control plants. Furthermore, it has been suggested that (E)-β-ocimene may be sequestered by larvae of H. erato phyllis as a component of the odoriferous bouquet of the abdominal scent glands present in adult males, which play a role in sexual communication.     

Speech in same- and different-sex twins 4 and 5 years old.

The purpose of this study was to examine the impact of the sex makeup of pairs of twins on language acquisition. Past research indicated that this variable plays a role in speech problems of twin children. The questions raised were whether being a boy or a girl and having a boy or girl co-twin affected linguistic performance. A language test was given to 30 pairs of boy-girl twins, 16 pairs of boy twins, and 16 pairs of girl twins whose average age was 4 years 8 months. Their test scores confirmed our hypotheses. The poorest performance was obtained by the boy twin pairs and the best performance, by either the girl twin pairs or the different-sex pairs. The results were interpreted in the light of findings on language learning differences between girls and boys, and also in terms of Vygotsky's zone of proximal development.     

Recherches sur la morphogénèse du canal de Müller chez les Oiseaux

Résumé L'analyse de certains points de la morphogénèse du canal de Müller et du rôle joué par le canal de Wolff dans la formation de l'oviducte a été abordée à l'aide de diverses méthodes expérimentales (blocage de l'ébauche müllérienne par un obstacle mécanique ou par une irradiation localisée par les rayons X).Les résultats obtenus soulignent la formation et l'évolution indépendante des 2 tissus, l'epithélium interne et le mésenchyme périphérique, qui composent la jeune ébauche müllérienne.L'épithélium interne se met en place par le jeu de la croissance crânio-caudale d'une ébauche primitive formée au niveau de l'ostium et induite par le canal de Wolff.Le mésenchyme périphérique se forme «in situ», aux dépens de la crÊte mullérienne qui est elle-mÊme induite par le canal de Wolff.Chez les Oiseaux, le développement de l'oviducte reste donc dépendant de l'uretère primaire, du fait de la double action inductrice exercée par le canal de Wolff sur les deux tissus constituant primitivement le canal de Müller.

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Researches on Mullerian duct morphogenesis in birdsII. Experimental study

Summary Certain points in the Mullerian duct morphogenesis, and the role played by the Wolffian duct in oviduct formation, were studied with some experimental methods (by stopping the mullerian anlage with a mechanical obstacle, or by a localized irradiation with X-rays).The results emphasize the independent formation and evolution of the two tissues, the inner epithelium and the mesenchyme which compose the young mullerian anlage.The inner epithelium is formed by the cranio-caudad outgrowth of a primitive anlage, formed at the level of the ostium, and induced by the Wolffian duct.The peripheric mesenchyme is formed in situ, from the mullerian strip, which itself is induced by the Wolffian duct.In Birds, oviduct development depends upon the primary ureter, by means of the double inductive action exerted by the Wolffian duct upon both tissues constituting the Mullerian duct anlage.

     

High-performance liquid chromatographic determination of paclitaxel in rat serum: application to a toxicokinetic study

A simple and sensitive high-performance liquid chromatographic method is described for the determination of paclitaxel (Taxol^®) at 230 nm using a Nucleosil C₁₈ (5 μm) column and a methanol–water (70:30, v/v) mobile phase following a single-step extraction from serum with dichloromethane. The assay was validated against the classical criteria and was applied to a toxicokinetic study in rats after one or five, one per week) intraperitoneal administrations of 16 mg/kg Taxol^®.     

New PCR ribotypes of Clostridium difficile detected in children in Brazil

A total of 35 Brazilian isolates of Clostridium difficile from faecal stools and four isolates from hospital environments were analyzed by PCR ribotyping. A whole cell protein profile (as an alternative for serogrouping), in vitro toxin production and susceptibility to vancomycin, metronidazole and clindamycin were also investigated. All strains were typeable by both phenotypic and genotypic methods, and a total of 13 different PCR ribotypes were identified, of which seven (132, 133, 134, 135, 136, 142 and 143) were considered new types and accounted for 78.5% of all samples evaluated (including hospital environments). A non-toxigenic C. difficile PCR ribotype 133 was detected in all children groups examined (inpatients, outpatients and healthy children), whilst toxigenic PCR ribotypes 015, 131, 134 and 135 were associated mostly with symptomatic children. Serogroups G and D were disseminated both in patients from the community and from the pediatric hospital, with group G prevalent among outpatient children. All strains were susceptible to vancomycin and metronidazole but high levels of resistance to clindamycin were found, especially among serogroups G and D. Co-existence of different ribotypes and serogroups in the same individual was observed. The new seven ribotypes found in this investigation may represent strains characteristic of this region of Brazil.