Maternal size and age affect offspring sex ratio in the solitary egg parasitoid Anaphes nitens

In this study, the effects of maternal age, diet, and size on offspring sex ratio were investigated for the solitary egg parasitoid, Anaphes nitens Girault (Hymenoptera: Mymaridae), both outdoors, during the winter, and inside a climatic chamber under favourable constant conditions. During the winter of 2005–2006, each of seven groups containing 40 1‐day‐old females was mated and randomly distributed among two treatments: (treatment 1) a droplet of undiluted honey ad libitum + one fresh egg capsule of the snout beetle Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae) as host; (treatment 2) drops of water + one fresh egg capsule of G. scutellatus. We recorded the lifetime fecundity, the daily sex allocation, and the lifetime offspring sex ratio to study the existence of a relationship with maternal characteristics. Moreover, we assessed the effect of location (outdoors vs. indoors) and group (groups are representative of early, mid, and late winter) on sex ratio. The most important factor that biased the sex ratio was maternal body size: larger females of both treatments produced more female offspring. As females of A. nitens could gain more advantage than males from body size, larger mothers have a higher fitness return if they produce more daughters. The effect of the treatment was significant: starved females produced more females. Location and group were not significant. Fecundity and sex ratio were age dependent. Old mothers that received honey (treatment 1) had fewer offspring and a more male‐biased offspring sex ratio, probably due to reproductive senescence and sperm depletion. Starved females (treatment 2) experienced reproductive decline earlier, perhaps because they invested more energy in maintenance rather than in reproduction.     

Field Trial with the Entomopathogenic Fungus Metarhizium anisopliae var. acridum against Bands of the Grasshopper Rhammatocerus schistocercoides in Brazil

The efficacy of a mycoinsecticide formulated in vegetable oil was tested in Brazil against the grasshopper Rhammatocerus schistocercoides . A set of experiments was conducted in the Chapada dos Parecis region (Mato Grosso state), a permanent zone of outbreaks for this pest. Experiments were performed in zones of natural vegetation, against grasshopper bands in the third nymphal instar. Three nymphal bands were treated with a mycoinsecticide formulation based on conidia of the entomopathogenic fungus Metarhizium anisopliae var. acridum ( =M. flavoviride ), strain CG 423. Three non-treated bands were used as control. The application was made with the aid of a hand-held ULV sprayer adjusted to deliver 2 l of the formulation ha -1 , each containing 1 ×10 13 conidia. Treatments were limited to the surface of the grasshopper bands and their immediate borders (5-10 m). The efficacy of the mycoinsecticide was evaluated through band survival after treatment (grasshopper numbers, surface, density, behaviour and daily movement of the band), allowing the insects to move freely in their natural environment. Insects were regularly surveyed and maintained in the laboratory, allowing estimates of the infection rate. Field and laboratory studies showed a clear effect of the product 10 days after treatment. At 14 days post-spraying, mortality caused by the mycoinsecticide in the field was approximately 88%.     

Planktonic egg masses of the diamond-shaped squid Thysanoteuthis rhombus in the eastern Atlantic and the Mediterranean Sea

Eight planktonic egg masses of the diamond-shaped Thysanoteuthisrhombus observed from 1995 to 2000 are described. Four werefound in the western Mediterranean and the others were foundoff the Canary Islands. The egg masses from the Canary Islandsare the first records for the eastern Atlantic. All were foundnear the surface at the end of summer and the beginning of autumn.The planktonic egg masses were dense, resilient oblong cylinderswith rounded tips ranging from 80 to 130 cm in length and between15 and 20 cm in diameter. Egg capsule dimensions ranged from2.8 to 3.4 mm and total length of the newly hatched paralarvaewas between 2.5 and 2.8 mm. Each egg mass contained an estimated24 100–43 800 eggs. Some new characters that should helpidentification of the paralarvae, such as arm formulae, presenceof an incipient keel-shaped membrane on some arms, and the typeand chromatophore pattern are given. Ecological factors influencingthe presence and distribution of these egg masses are discussed.     

Variability of Leishmania (Leishmania) infantum among stocks from immunocompromised, immunocompetent patients and dogs in Spain

Abstract Leishmania (Leishmania) infantum is the causative agent of both the cutaneous and visceral forms of leishmaniasis in southwest Europe; the dog is the main reservoir. In order to identify the L. (L.) infantum zymodemes present in Spain, a total number of 85 Leishmania stocks isolated from dogs (31), HIV-positive patients (46) with visceral or cutaneous leishmaniasis, a patient with visceral leishmaniasis complicating renal transplantation (1) and immunocompetent patients (7) with visceral or cutaneous leishmaniasis, have been characterized by isoenzyme typing. All canine stocks were MON-1, which is the most widespread zymodeme in the Mediterranean area. In immunocompetent patients three zymodemes were found: MON-1 (2), MON-24 (2) and MON-34 (3). Nine different zymodemes were obtained in stocks from HTV co-infected patients, indicating a higher variability of L. (L.) infantum amongst them: MON-1 (in 21 stocks), MON-24 (7), MON-28 (1), MON-29 (3), MON-33 (7), MON-34 (1) and MON-183 (4). Two new zymodemes, MON-198 (1) and MON-199 (1), were described among HIV patients from Spain. The stock from the renal transplanted patient was MON-1. The exclusive presence of certain zymodemes in immunocompromised patients and their absence in typical cases of cutaneous and visceral     

Variable expression of the herpes simplex virus thymidine kinase gene in Nicotiana tabacum affects negative selection

The potentials and limitations of negative-selection systems based on the human herpes simplex virus thymidine kinase type-1 (HSVtk) gene, which causes sensitivity to the nucleoside analog ganciclovir, were examined in tobacco as a model system. There were great differences between individual HSVtk⁺ transgenic plants in ganciclovir sensitivity. Inhibition of growth while under selection correlated with HSVtk-tianscnpt levels. Negative selection against HSVtk⁺ transformants at the level of Agrobacterium-mediated transformation using a ganciclo-vir/kanamycin double-selection medium (the positive selection marker neomycin phosphotransferase-II gene was in the transformation vector) resulted in a three- to six-fold reduction in the frequency of kanamycin-resistant shoots. The efficiency of negative selection in this case was limited due to the great variation in HSVtk expression, i.e., the frequently occurring transformants with low, or no, ganciclovir sensitivity escaping negative selection. Two independently constructed HSVtk genes showed the same variability of the phenotype in Nicotiana tabacum transformants. Distinct phenotypes, ranging from no regeneration through abnormal or delayed regeneration, were observed when leaf segments were placed on shoot-inducing medium supplemented with 10^–6–10^–3 M ganciclovir. The highest HSVtk mRNA and ganciclovir sensitivity levels were observed in plants which were transformed with the pSLJ882 chimeric construct. The pSLJ882 plant expression vector carried the coding sequence of HSVtk, whereas plasmid pCX305.1 carried an HSVtk construct retaining the untranslated 5 leader and viral 3 regions. The pCX305.1 transformants showed, at most, a delayed formation of shoots with thin stems and very narrow leaves. Ganciclovir sensitivity showed typical Mendelian segregation. A gene-dosage effect was also seen at the seedling level in the progeny of two transgenic lines.     

The use of seaweeds as bioindicators of natural and anthropogenic contaminants in northern Chile

Twelve seaweed species were sampled from 1991 to 1993 in order to detect the impact of natural mineralization and mining in 14 contaminated and non-contaminated areas (between 24° and 30° S — more than 1200 km) along the northern Chilean coast. Instrumental neutron activation analysis (INAA) was used to measure the concentration of 17 chemical elements. The results showed high variability in and between species, among sampling sites and times of collection. The high values of heavy metals in seaweeds suggest that these marine organisms can be used as biological indicators for detecting mineralization and anthropogenic impact on coastal marine communities.Facultad de Ciencias del Mar     

Age related patterns of immunoglobulin serum levels in the Quechua Indians of Andean Mountains

Age-dependent changes of IgA, IgG, IgM, and IgD serum levels in a population of Quechua Indians of Peruvian Andes at 4 300 m were investigated. A first increase and a subsequent decrease in IgA and IgM levels were observed with advancing age. IgG and IgD only display an increase during development. More or less pronounced sex-related changes were also found in all Ig classes, the sex dependent pattern of IgA being the more evident one. It has been suggested that sexual, genetic and environmental influences strongly superimpose to high altitude related changes in Ig profile during ageing.     

Evidence for a Turner syndrome locus or loci at Xp11.2-p22.1.

Turner syndrome is the complex human phenotype associated with complete or partial monosomy X. Principle features of Turner syndrome include short stature, ovarian failure, and a variety of other anatomic and physiological abnormalities, such as webbed neck, lymphedema, cardiovascular and renal anomalies, hypertension, and autoimmune thyroid disease. We studied 28 apparently nonmosaic subjects with partial deletions of Xp, in order to map loci responsible for various components of the Turner syndrome phenotype. Subjects were carefully evaluated for the presence or absence of Turner syndrome features, and their deletions were mapped by FISH with a panel of Xp markers. Using a statistical method to examine genotype/phenotype correlations, we mapped one or more Turner syndrome traits to a critical region in Xp11.2-p22.1. These traits included short stature, ovarian failure, high-arched palate, and autoimmune thyroid disease. The results are useful for genetic counseling of individuals with partial monosomy X. Study of additional subjects should refine the localization of Turner syndrome loci and provide a rational basis for exploration of candidate genes.     

Effect of Chronic Ethanol Treatment on the γ-Aminobutyric Acid-Mediated Enhancement of [3H]Flunitrazepam Binding in Rat Cortex and Hippocampus

The mechanism by which ethanol affects the gamma-aminobutyric acid (GABA)/benzodiazepine complex is not clear. It is known that ethanol enhances the Cl- influx mediated by the GABAA receptor complex, and although chronic ethanol administration does not change the KD or Bmax for [3H]flunitrazepam binding, some reports have suggested that it could modify the modulation of benzodiazepine binding produced by GABA. In the present work, we studied the effect of chronic ethanol treatment on the modulation by GABA of [3H]flunitrazepam binding, using light microscopic autoradiography. This technique allows the measurement of densities of benzodiazepine receptors in different brain areas, the visual cortex and hippocampus, which appear to constitute the anatomical support for the behavioral and physiological responses affected by ethanol. We found enhancement of benzodiazepine binding by GABA at concentrations of greater than 10(-6) M for the various cortical and hippocampal areas studied from both control and ethanol-treated animals; this enhancement peaked at 10(-4) M GABA but decreased at 10(-3) M GABA. We found a clear effect of ethanol treatment on the modulatory properties of GABAA receptor, in both cortex and hippocampus, although only in cortex were the differences statistically significant between control and ethanol-treated animals.