Steller Sex: Infidelity and Sexual Selection in a Social Corvid (Cyanocitta stelleri)

Genetic analysis of avian mating systems has revealed that more than 70% of monogamous species show incidence of offspring parentage that does not match the social partner. Extra-pair parentage (EPP) has been linked to a variety of factors, including size and symmetry of ornamental traits, coloration, resource availability, and local conspecific density. We examined how ornamental plumage traits of individual Steller''s jays (Cyanocitta stelleri) and territory characteristics influence genetic fidelity of socially monogamous pairs. We used seven highly polymorphic microsatellite markers to assign paternity to 79 offspring, and identified 12 (15.2%) as extra-pair young (EPY). Steller''s jays with extra-pair young had significantly lower values of feather brightness and hue, indicating more ultraviolet-blue shifted coloration, and nested in closer proximity to the forest edge than Steller''s jays with no detected EPY. Body size, crest height, asymmetry of ornamental crest stripes, as well as vegetative composition of territories and their proximity to supplemental feeders appeared to have little relationship to EPP. These results indicate that extra-pair parentage plays a role in the evolution of secondary sexual characteristics in both sexes, and suggest local density and availability of resources may influence Steller''s jay mating dynamics.     

Preference for outbred host plants and positive effects of inbreeding on egg survival in a specialist herbivore

Inbreeding can profoundly affect the interactions of plants with herbivores as well as with the natural enemies of the herbivores. We studied how plant inbreeding affects herbivore oviposition preference, and whether inbreeding of both plants and herbivores alters the probability of predation or parasitism of herbivore eggs. In a laboratory preference test with the specialist herbivore moth Abrostola asclepiadis and inbred and outbred Vincetoxicum hirundinaria plants, we discovered that herbivores preferred to oviposit on outbred plants. A field experiment with inbred and outbred plants that bore inbred or outbred herbivore eggs revealed that the eggs of the outbred herbivores were more likely to be lost by predation, parasitism or plant hypersensitive responses than inbred eggs. This difference did not lead to differences in the realized fecundity as the number of hatched larvae did not differ between inbred and outbred herbivores. Thus, the strength of inbreeding depression in herbivores decreases when their natural enemies are involved. Plant inbreeding did not alter the attraction of natural enemies of the eggs. We conclude that inbreeding can significantly alter the interactions of plants and herbivores at different life-history stages, and that some of these alterations are mediated by the natural enemies of the herbivores.     

The Effect of a Stroop-like Task on Postural Control in Dyslexic Children

The influence of a secondary task on concurrent postural control was explored in twenty-one dyslexic children (mean age: 10.4±0.3 years). Data were compared with twenty age-matched non-dyslexic children. As a secondary task, a modified Stroop test was used, in which words were replaced with pictures of fruits. The postural control of children was recorded in standard Romberg condition as the children were asked to name the colour of fruits appearing consecutively on a computer screen. Two conditions were tested: a congruent condition, in which the fruit was drawn in its natural ripe colour, and a non-congruent colour condition (NC), in which the fruit was drawn in three abnormal colours. A fixating condition was used as baseline. We analyzed the surface, length and mean speed of the center of pressure and measured the number of correct responses in the Stroop-like tasks. Dyslexic children were seen to be significantly more unstable than non-dyslexic ones. For both groups of children, the secondary task significantly increased postural instability in comparison with the fixating condition. The number of correct responses in the modified Stroop task was significantly higher in the non-dyslexic than in the dyslexic group. The postural instability observed in dyslexic children is in line with the cerebellar hypothesis and supports the idea of a deficit in automatic performance in such children. Furthermore, in accordance with cross domain competition model, our findings show that attentional resources are used to a greater extent by the secondary task than in controlling body stability.     

Mapping a floral trait in Shepherds purse – ‘Stamenoid petals’ in natural populations of Capsella bursa-pastoris (L.) Medik

Striking feature of angiosperm diversity is the huge number of variations in corolla morphology including complex innovations like variations in symmetry or the identity and number of floral organs. Throughout the Brassicaceae, the disymmetric flower structure is highly conserved. Still, quite a few floral alterations occur like a variant of Common Shepherds purse (Capsella bursa-pastoris), in which all petals have been transformed into additional stamens. This “decandric” phenotype has been reported for the first time about 200 years ago. In some of the original locations the variant has been recovered recently. The long term persistence indicates the establishment of an evolutionary novelty in wild populations in sympatric occurrence with wild-type plants. Due to this fact the floral variant has become an interesting model for evolutionary studies. The phenotype is heritable and just a single locus, termed “Stamenoid petals” (Spe), is assumed to be involved in the molecular origin. To unravel the chromosomal localization of this locus, a linkage map analysis was carried out using molecular markers (AFLPs, RAPDs). The final map includes 15 linkage groups and the floral trait was integrated on linkage group 12 (CBP12) including six AFLP markers. Out of these, five markers were successfully sequenced and revealed sequence identities with chromosome IV of the A. thaliana genome. Interestingly, AGAMOUS is located on this chromosome, the only class C floral organ identity gene in the A. thaliana genome, which is compatible with the assumption that Spe is an allele of AGAMOUS rather than a regulator of that gene.     

Effect of polyamine deficiency on proteins involved in Okazaki fragment maturation

Polyamine depletion causes S phase prolongation, and earlier studies indicate that the elongation step of DNA replication is affected. This led us to investigate the effects of polyamine depletion on enzymes crucial for Okazaki fragment maturation in the two breast cancer cell lines MCF-7 and L56Br-C1. In MCF-7 cells, treatment with N(1),N(11)-diethylnorspermine (DENSPM) causes S phase prolongation. In L56Br-C1 cells the prolongation is followed by massive apoptosis. In the present study we show that L56Br-C1 cells have substantially lower basal expressions of two Okazaki fragment maturation key proteins, DNA ligase I and FEN1, than MCF-7 cells. Thus, these two proteins might be promising markers for prediction of polyamine depletion sensitivity, something that can be useful for cancer treatment with polyamine analogues. DENSPM treatment affects the cellular distribution of FEN1 in L56Br-C1 cells, but not in MCF-7 cells, implying that FEN1 is affected by or involved in DENSPM-induced apoptosis.     

Effect of auranofin on the mitochondrial generation of hydrogen peroxide. Role of thioredoxin reductase

The mitochondrial production of hydrogen peroxide, in the presence of different respiratory substrates (succinate, glutamate, malate and isocitrate), is stimulated by submicromolar concentrations of auranofin, a highly specific inhibitor of thioredoxin reductase. This effect is particularly evident in the presence of antimycin. Auranofin was also able to unmask the production of hydrogen peroxide occurring in the presence of rotenone. However, at variance with whole mitochondria, auranofin does not stimulate hydrogen peroxide production in submitochondrial particles indicating that it does not alter the formation of hydrogen peroxide by the respiratory chain but prevents its removal. As the mitochondrial metabolism of hydrogen peroxide proceeds through the peroxidases linked to glutathione or thioredoxin, the relative efficiency of the two systems and the effects of auranofin were tested. In conclusion, the inhibition of thioredoxin reductase determines an increase of the basal flow of hydrogen peroxide leading to a more oxidized condition that alters the mitochondrial functions.     

Long-term in vivo experience of an electrochemical sensor using the potential step technique for measurement of mixed venous oxygen pressure

An implantable amperometric blood oxygen sensor was developed to improve rate adaptation of heart pacemakers. Two different working electrode materials in direct contact with the blood were tested, smooth glassy carbon and gold. Reference electrodes of Ag/AgCl and porous pyrolytic carbon were evaluated. A counter electrode being the titanium housing of the pulse generator was partly coated with carbon. An implantable pacemaker system with chronocoulometric oxygen detection was developed. Heart synchronous potential steps were periodically applied to the 7.5 mm² working electrode in the atrium. Both single and double potential step techniques were evaluated. The oxygen diffusion limited current was used to calculate the stimulation rate. Bench tests and studies on 31 animals were performed to evaluate long-term stability and biocompatibility. In five dogs, the AV node was destroyed by RF ablation to create a realistic animal model of a pacemaker patient. Sensor stability and response to exercise was followed up to a maximum implantation time of 4 years. Post-mortem examinations of the electrode surfaces and tissue response were performed. The results show that a gold electrode is more stable than glassy carbon. The Ag/AgCl reference was found not to be biocompatible, but activated carbon was stable enough for use as reference for the potentiostat. Double potential steps stabilize the sensor response in comparison to single steps. Blood protein adsorption on the gold surface decreased the oxygen transport but not the reaction efficacy. No adverse tissue reactions were observed.     

The human chorionic gonadotropin-beta arginine68 to glutamic acid substitution fixes the conformation of the C-terminal peptide

Wild-type human chorionic gonadotropin (hCG) has been used as a contraceptive vaccine. However, extensive sequence homology with LH elicits production of cross-reactive antibodies. Substitution of arginine(68) of the beta-subunit (hCG(beta)) with glutamic acid (R68E) profoundly reduces the cross-reactivity while refocusing the immune response to the hCG(beta)-specific C-terminal peptide (CTP). To investigate the molecular basis for this change in epitope usage, we immunized mice with a plasmid encoding a truncated hCG(beta)-R68E chain lacking the CTP. The animals produced LH-cross-reactive antibodies, suggesting that the refocused immunogenicity of R68E is a consequence of epitope masking by a novel disposition of the CTP in the mutant rather than a structural change in the cross-reactive epitope region. This explanation was strongly supported by surface plasmon resonance analysis using a panel of anti-hCG(beta)-specific and anti-hCG(beta)/LH cross-reactive monoclonal antibodies (mAbs). Whereas the binding of the LH cross-reactive mAbs to hCG(beta)-R68E was eliminated, mAbs reacting with hCG(beta)-specific epitopes bound to hCG(beta) and hCG(beta)-R68E with identical affinities. In a separate series of experiments, we observed that LH cross-reactive epitopes were silent after immunization with a plasmid encoding a membrane form of hCG(beta)-R68E, as previously observed with the soluble mutant protein itself. In contrast, the plasmid encoding the soluble secreted form of hCG(beta)-R68E evoked LH cross-reactive antibodies, albeit of relatively low titer, suggesting that the handling and processing of the proteins produced by the two constructs differed.     

The organization of two related subfamilies of a human tandemly repeated DNA is chromosome specific

Summary Several clones containing clusters of repetitive elements were isolated from a human chromosome 22 specific library. An EcoRI-XhoI fragment of 860bp was subcloned and was shown to belong to a family of tandemly repeated DNA linked to the Y-specific 3.4 kb HaeIII band. This probe hybridizes to several sets of sequences or subfamilies. The most abundant subfamily is a 1.8kb long sequence containing one EcoRV site, and in most repeats, one AvaII and one KpnI site. Using human-rodent somatic cell hybrid DNA, we have shown that this cluster is present on human chromosome 9 although presence on chromosome 15 is not excluded. Another subfamily, 6.1 kb long, appears to be exclusive of chromosome 16. By in situ hybridization with metaphasic chromosomes, these sets of repeats were mapped to the constitutive heterochromatin of a few chromosomes. Coexistence in one genome of long tandem repeats of distinct organization but similar length may represent the outcome of a continuous process of fixation of variant sequences. Homologous repeats are also abundant in four higher primate genomes (Orangutan, gorilla, chimpanzee, and man) but absent in other primates (African green monkey, rhesus monkey, baboon, and mouse lemur).     

Men’s Knowledge of Obstetric Danger Signs,Birth Preparedness and Complication Readiness in Rural Tanzania

BackgroundMen’s involvement in reproductive health is recommended. Their involvement in antenatal care service is identified as important in maternal health. Awareness of obstetric danger signs facilitates men in making a joint decision with their partners regarding accessing antenatal and delivery care. This study aims to assess the level of knowledge of obstetric complications among men in a rural community in Tanzania, and to determine their involvement in birth preparedness and complication readiness.MethodsA cross-sectional survey was conducted where 756 recent fathers were invited through a two-stage cluster sampling procedure. A structured questionnaire was used to collect socio-demographic characteristics, knowledge of danger signs and steps taken on birth preparedness and complication readiness. Data were analyzed using bivariate and multivariable logistic regression to determine factors associated with being prepared, with statistically significant level at p<0.05.ResultsAmong the invited men, 95.9% agreed to participate in the community survey. Fifty-three percent could mention at least one danger sign during pregnancy, 43.9% during delivery and 34.6% during the postpartum period. Regarding birth preparedness and complication readiness, 54.3% had bought birth kit, 47.2% saved money, 10.2% identified transport, 0.8% identified skilled attendant. In general, only 12% of men were prepared. Birth preparedness was associated with knowledge of danger signs during pregnancy (AOR = 1.4, 95% CI: 1.8-2.6). It was less likely for men living in the rural area to be prepared (AOR=0.6, 95% CI; 0.5-0.8).ConclusionThere was a low level of knowledge of obstetric danger signs among men in a rural district in Tanzania. A very small proportion of men had prepared for childbirth and complication readiness. There was no effect of knowledge of danger signs during childbirth and postpartum period on being prepared. Innovative strategies that increase awareness of danger signs as well as birth preparedness and complication readiness among men are required. Strengthening counseling during antenatal care services that involve men together with partners is recommended.