Haplotype analysis of p53 polymorphisms: Arg72Pro,Ins16bp and G13964C in Tunisian patients with familial or sporadic breast cancer

Background: The p53 polymorphisms have been extensively studied as putative breast cancer susceptibility variants. The present study was undertaken to investigate the association of p53 Arg72Pro, Ins16bp and G13964C polymorphisms and their haplotypes with breast cancer risk in Tunisian women. Methods: Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on 159 patients and 132 controls. Results: The G13964C intronic variant was significantly associated with familial breast cancer risk (p = 0.0018) while the genotypic distribution was similar for p53 Arg72Pro and Ins16bp in patients and controls. Moreover, the (NoIns-C), (Arg-C) and (NoIns-Arg-C) haplotypes were significantly associated with familial breast cancer risk (p = 0.0021, p = 0.0096 and p = 0.0084, respectively) while there was a trend of association between the (Ins-Arg) and (Ins-Arg-G) haplotypes and the risk of sporadic breast cancer. Only the G/C genotype as well as the (NoIns-C) haplotype remained significant after correction for multiple testing. Conclusion: Our data revealed an association between the G/C genotype and the (NoIns-C) haplotype and the risk of familial breast cancer in Tunisian women. However, these observations need to be confirmed due to the limited statistical power of our study and the small number of cases.     

Male‐killer dynamics in Danaus chrysippus (L.) (Lepidoptera: Nymphalidae) in East Africa

Within certain regions in East Africa, the butterfly Danaus chrysippus (L.) shows female‐biased population sex ratio, because of the production by some females of all‐female broods, as a result of infection by maternally inherited, male‐killing bacterium of the genus Spiroplasma. In this study, we describe a 3‐year field survey for the population dynamics of the male‐killing Spiroplasma in D. chrysippus in four independent localities, namely Uganda, Ghana, Sudan and Madagascar. The prevalence of the bacterium was found to show extensive variations at multiple scales among different sites, in various countries, seasons and years. A novel, selection‐based hypothesis was suggested to explain the high variability of male‐killer prevalence over space and time, based on the existence of an adaptive link between larval food‐plant density and the magnitude of resource reallocation fitness advantage for the male‐killer.     

Darwin's vexing contrivance: a new hypothesis for why some flowers have two kinds of anther

Heteranthery, the presence of two or more anther types in the same flower, is taxonomically widespread among bee-pollinated angiosperms, yet has puzzled botanists since Darwin. We test two competing hypotheses for its evolution: the long-standing ‘division of labour'' hypothesis, which posits that some anthers are specialized as food rewards for bees whereas others are specialized for surreptitious pollination, and our new hypothesis that heteranthery is a way to gradually release pollen that maximizes pollen delivery. We examine the evolution of heteranthery and associated traits across the genus Clarkia (Onagraceae) and study plant–pollinator interactions in two heterantherous Clarkia species. Across species, heteranthery is associated with bee pollination, delayed dehiscence and colour crypsis of one anther whorl, and movement of that anther whorl upon dehiscence. Our mechanistic studies in heterantherous species show that bees notice, forage on and export pollen from each anther whorl when it is dehiscing, and that heteranthery promotes pollen export. We find no support for division of labour, but multifarious evidence that heteranthery is a mechanism for gradual pollen presentation that probably evolved through indirect male–male competition for siring success.     

End-of-life issues as perceived by Lebanese judges

Objectives: to assess the attitudes of judges in Beirut, Lebanon, regarding end-of-life issues such as assisted suicide and withholding or withdrawing life-sustaining treatment.
Subjects and Methods: 85% of all currently acting and in-training judges and public prosecutors in Beirut (N =135) were surveyed using a mailed questionnaire that assessed attitudes toward intervention in five hypothetical cases. The associations of attitudes, on a scale from least to most 'sympathetic' toward assisting those who desire to end their lives, were measured by a variety of personal, social and professional variables.
Results: younger individuals, and those who have not yet been formally appointed as judges, were significantly more sympathetic to withdrawal or withholding of life-sustaining devices when patients or their proxies requested it, and more in support of assisted suicide. Gender, religious denomination, religious practice, and personal experience with prolonged illness leading to death among close friends or family, were generally not significant predictors of respondents' attitudes. Years of experience as a judge correlated strongly with age and may have contributed to its predictive effect.
Discussion and conclusions: a relatively more sympathetic attitude among younger judges, many of them women, and among trainees, may reflect a historical evolution in younger age-groups in Lebanon today. A survey of opinions in the public may help reach a more conclusive understanding in this regard. In any case, judges in Lebanon will remain important partners in the debate, as they will continue to be the final interpreters of the letter of the law in end-of-life issues.     

Small and overlooked: Phylogeny of the genus Trigonodactylus (Squamata: Gekkonidae), with the first record of Trigonodactylus arabicus from Jordan

Geckos of the genus Trigonodactylus are widely distributed in the sand deserts of the Arabian Peninsula. Three species of this genus are currently recognized, with a fourth one, Stenodactylus pulcher, which placement within Trigonodactylus has been tentatively suggested, but not yet confirmed. We present a phylogenetic analysis of the genus Trigonodactylus with new specimens collected in central Saudi Arabia and southern Jordan. New genetic data has been generated from three mitochondrial markers to investigate the phylogenetic relationships of all species of the genus and to assess the putative generic assignment of S. pulcher. Our results confirm that S. pulcher indeed belongs within Trigonodactylus, branching as a sister lineage to all other species of the genus. The new samples cluster within Trigonodactylus arabicus, thus confirming the genetic homogeneity of the species across its large and seemingly inhospitable range. The new specimen collected in southern Jordan represents the first record for the country and a considerable range extension to the northwest from all previously reported localities. Our findings and discovery of a new species for Jordan highlight the need of more field surveys to be carried out in the underexplored parts of Jordan and northern Saudi Arabia, as these places still hold a potential for new discoveries and are crucial for understating the biogeography of the Arabian herpetofauna.     

Enzymatic hydrolysis of olive wastewater for hydroxytyrosol enrichment

Aspergillus niger broth culture on wheat bran was assessed for olive wastewater (OW) hydrolysis in order to release hydroxytyrosol (HT). The enzyme profiles of this culture broth gave essentially (IU/L): 3000 β-glucosidase and 100 esterase. Hydrolysis activity of A. niger enzyme preparation was evaluated by using three substrates: raw OW, phenolic fraction extracted from OW by ethyl acetate and its corresponding exhausted fraction. Large amounts of free simple phenolics were released from exhausted fraction and raw OW after enzymatic treatment. HPLC analyses show that HT was the main phenolic compound. One step of ethyl acetate extraction of hydrolysed OW allowed the recovery of 0.8 g of HT per litre of OW. The antioxidant activity of extracts from OW and exhausted fraction, measured by DPPH method, was drastically enhanced after hydrolysis treatment. This study demonstrates that hydrolysed OW is a potential source of bioactive phenolic compounds with promising applications in food and pharmaceutical industries.     

Reassessment of Sex Role-Reversal Hypothesis in the Tropical Butterfly Acraea encedon (Lepidoptera: Nymphalidae)

Species with extremely female-biased sex ratios are expected to show alteration in the normal sex roles, as a response to male scarcity. The tropical butterfly Acraea encedon is known to be infected with a male-killing bacterium of the genus Wolbachia, which has led to severe sex ratio distortion in some populations where more than 95 % of wild females are infected with the male-killer. Thus, the aggregation of female A. encedon at resource-free landmarks has been interpreted as “female lekking” behaviour, a sex role-reversed form of lekking normally seen in males of many animals. For this paper, sites in Uganda where female-leks have previously been reported (in 1998) were revisited and surveyed for both sex ratio and bacterial prevalence, for 3 years (2005–2007). The hypothesis of sex role-reversal in A. encedon was evaluated in light of the field data obtained. The study concluded that the response of host populations to the gradual spread of the male-killer toward fixation occurs initially at the behavioural level, as sex role-reversal, and finally at the demographic level, by succumbing to extinction.     

Evolution of alternative insect life histories in stochastic seasonal environments

Deterministic seasonality can explain the evolution of alternative life history phenotypes (i.e., life history polyphenism) expressed in different generations emerging within the same year. However, the influence of stochastic variation on the expression of such life history polyphenisms in seasonal environments is insufficiently understood. Here, we use insects as a model and explore (1) the effects of stochastic variation in seasonality and (2) the life cycle on the degree of life history differentiation among the alternative developmental pathways of direct development and diapause (overwintering), and (3) the evolution of phenology. With numerical simulation, we determine the values of development (growth) time, growth rate, body size, reproductive effort, adult life span, and fecundity in both the overwintering and directly developing generations that maximize geometric mean fitness. The results suggest that natural selection favors the expression of alternative life histories in the alternative developmental pathways even when there is stochastic variation in seasonality, but that trait differentiation is affected by the developmental stage that overwinters. Increasing environmental unpredictability induced a switch to a bet‐hedging type of life history strategy, which is consistent with general life history theory. Bet‐hedging appeared in our study system as reduced expression of the direct development phenotype, with associated changes in life history phenotypes, because the fitness value of direct development is highly variable in uncertain environments. Our main result is that seasonality itself is a key factor promoting the evolution of seasonally polyphenic life histories but that environmental stochasticity may modulate the expression of life history phenotypes.     

Differential Postnatal Development of Monoamine Oxidases A and B in the Blood-Brain Barrier of the Rat

Abstract: We studied the monoamine metabolizing mitochondrial enzyme, monoamine oxidase (MAO), in cerebral microvessels obtained from postnatally developing rats by measuring the specific binding of [³H]pargyline, an irreversible inhibitor of MAO, and the rate of oxidation of three known MAO substrates: benzylamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and tryptamine. MAO activity increased postnatally, with the greatest increase occurring in the second week and reaching a peak at 3 weeks of age. A concomitant increase in MAO of the cerebral cortex also occurred, but was several-fold less than that of cerebral microvessels. Using clorgyline and deprenyl, relatively specific inhibitors of MAO-A and MAO-B, we showed that cerebral microvessels contain both forms of MAO at all ages, but there was a major preponderance in the postnatal development of MAO-B. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses of rat microvessels after [³H]pargyline binding also showed two distinct bands of radioactivity at all ages. These two bands corresponded to molecular weights of ∼6.5,000 for MAO-A and -60,000 for MAO-B. SDS-PAGE resuits of brain microvessels obtained from 1-, 14-, and 42-day-old rats confirm the differential postnatal development of MAO-B in rat brain microvessels.