Insertion of a malE B-Galactosidase fusion protein into the envelope of Escherichia coli disrupts biogenesis of outer membrane proteins and processing of inner membrane proteins

The synthesis of a membrane-bound MalE ,B-galactosidase hybrid protein, when induced by growth of Escherichia coli on maltose, leads to inhibition of cell division and eventually a reduced rate of mass increase. In addition, the relative rate of synthesis of outer membrane proteins, but not that of inner membrane proteins, was reduced by about 50%o. Kinetic experiments demonstrated that this reduction coincided with the period of maximum synthesis of the hybrid protein (and another maltose-inducible protein, LamB). The accumulation of this abnormal protein in the envelope therefore appeared specifically to inhibit the synthesis, the assembly of outer membrane proteins, or both, indicating that the hybrid protein blocks some export site or causes the sequestration of some limiting factor(s) involved in the export process. Since the MalE protein is normally located in the periplasm, the results also suggest that the synthesis of periplasmic and outer membrane proteins may involve some steps in common. The reduced rate of synthesis of outer membrane proteins was also accompanied by the accumulation in the envelope of at least one outer membrane protein and at least two inner membrane proteins as higher-molecular-weight forms, indicating that processing (removal of the N-terminal signal sequence) was also disrupted by the presence of the hybrid protein. These results may indicate that the assembly of these membrane proteins is blocked at a relatively late step rather than at the level of primary recognition of some site by the signal sequence. In addition, the results suggest that some step common to the biogenesis of quite different kinds of envelope protein is blocked by the presence of the hybrid protein.

Genome sequence of the Drosophila melanogaster male-killing Spiroplasma strain MSRO endosymbiont.

Spiroplasmas are helical and motile members of a cell wall-less eubacterial group called Mollicutes. Although all spiroplasmas are associated with arthropods, they exhibit great diversity with respect to both their modes of transmission and their effects on their hosts; ranging from horizontally transmitted pathogens and commensals to endosymbionts that are transmitted transovarially (i.e., from mother to offspring). Here we provide the first genome sequence, along with proteomic validation, of an endosymbiotic inherited Spiroplasma bacterium, the Spiroplasma poulsonii MSRO strain harbored by Drosophila melanogaster. Comparison of the genome content of S. poulsonii with that of horizontally transmitted spiroplasmas indicates that S. poulsonii has lost many metabolic pathways and transporters, demonstrating a high level of interdependence with its insect host. Consistent with genome analysis, experimental studies showed that S. poulsonii metabolizes glucose but not trehalose. Notably, trehalose is more abundant than glucose in Drosophila hemolymph, and the inability to metabolize trehalose may prevent S. poulsonii from overproliferating. Our study identifies putative virulence genes, notably, those for a chitinase, the H2O2-producing glycerol-3-phosphate oxidase, and enzymes involved in the synthesis of the eukaryote-toxic lipid cardiolipin. S. poulsonii also expresses on the cell membrane one functional adhesion-related protein and two divergent spiralin proteins that have been implicated in insect cell invasion in other spiroplasmas. These lipoproteins may be involved in the colonization of the Drosophila germ line, ensuring S. poulsonii vertical transmission. The S. poulsonii genome is a valuable resource to explore the mechanisms of male killing and symbiont-mediated protection, two cardinal features of many facultative endosymbionts. IMPORTANCE: Most insect species, including important disease vectors and crop pests, harbor vertically transmitted endosymbiotic bacteria. These endosymbionts play key roles in their hosts' fitness, including protecting them against natural enemies and manipulating their reproduction in ways that increase the frequency of symbiont infection. Little is known about the molecular mechanisms that underlie these processes. Here, we provide the first genome draft of a vertically transmitted male-killing Spiroplasma bacterium, the S. poulsonii MSRO strain harbored by D. melanogaster. Analysis of the S. poulsonii genome was complemented by proteomics and ex vivo metabolic experiments. Our results indicate that S. poulsonii has reduced metabolic capabilities and expresses divergent membrane lipoproteins and potential virulence factors that likely participate in Spiroplasma-host interactions. This work fills a gap in our knowledge of insect endosymbionts and provides tools with which to decipher the interaction between Spiroplasma bacteria and their well-characterized host D. melanogaster, which is emerging as a model of endosymbiosis.

Teachers' attitudes and beliefs about homosexuality

Schools play a key role in transmitting attitudes towards sexual diversity. Many studies stress the importance of teachers" and other professionals" attitudes towards gay men and/or lesbian women. This study evaluates attitudes and prejudices toward homosexuality in a sample of 254 elementary and high school teachers in Barcelona and its surrounding area. The results obtained using a scale of overt and subtle prejudice and a scale of perceived discrepancy of values indicate that discrepancy between likely behavior and personal values was significantly greater in women, those who hold religious beliefs, churchgoers and people without any gay or lesbian acquaintances. Approximately 88% of the teachers showed no type of prejudiced attitudes towards gay men and lesbian women. The experience of proximity to gay men and/or lesbian women reduces not only the discrepancy between personal values and likely behavior but also the presence of homophobic prejudice. It would be advisable to expand specific teacher training in the subject of sexual diversity in order to reduce prejudicial attitudes, thus fostering non-stereotyped knowledge of homosexuality

Neural Circuits: Male Mating Motifs.

Characterizing microcircuit motifs in intact nervous systems is essential to relate neural computations to behavior. In this issue of Neuron, Clowney et al. (2015) identify recurring, parallel feedforward excitatory and inhibitory pathways in male Drosophila's courtship circuitry, which might explain decisive mate choice.

How patient-centered do female physicians need to be? Analogue patients' satisfaction with male and female physicians' identical behaviors (Published online: 30 Aug 2014)

Previous research suggests that female physicians may not receive appropriate credit in patients' eyes for their patient-centered skills compared to their male counterparts. An experiment was conducted to determine whether a performance of higher (versus lower) verbal patient-centeredness would result in a greater difference in analogue patient satisfaction for male than female physicians. Two male and two female actors portrayed physicians speaking to a patient using high or low patient-centered scripts while not varying their nonverbal cues. One hundred ninety-two students served as analogue patients by assuming the patient role while watching one of the videos and rating their satisfaction and other evaluative responses to the physician. Greater verbal patient-centeredness had a stronger positive effect on satisfaction and evaluations for male than for female physicians. This pattern is consistent with the hypothesis that the different associations between patient-centeredness and patients' satisfaction for male versus female physicians occur because of the overlap between stereotypical female behavior and behaviors that comprise patient-centered medical care. If this is the case, high verbal patient-centered behavior by female physicians is not recognized as a marker of clinical competence, as it is for male physicians, but is rather seen as expected female behavior.

Les étudiant(e)s en médecine mènent une recherche dans La communauté [Male/female medical students conduct research in the community].

Pendant quatre semaines, les étudiant(e)s en médecine de 3e année de l'Université de Lausanne mènent une enquête dans la communauté sur le sujet de leur choix. L'objectif de ce module est de faire découvrir aux futurs médecins les déterminants non biomédicaux de la santé, de la maladie et de l'exercice de la médecine : les styles de vie, les facteurs psychosociaux et culturels, l'environnement, les décisions politiques, les contraintes économiques, les questions éthiques, etc. Par groupes de cinq, les étudiant(e)s commencent par définir une question de recherche originale et en explorent la littérature scientifique. Leur travail de recherche les amène à entrer en contact avec le réseau d'acteurs de la communauté concernés, professionnels ou associations de patients dont ils analysent les rôles et influences respectives. Chaque groupe est accompagné par un(e) tuteur(trice), enseignant(e) de la Faculté de biologie et de médecine de l'Université de Lausanne. Les étudiant(e)s présentent la synthèse de leurs travaux pendant un congrès de deux jours à la fin du module. Quatre travaux parmi les plus remarquables ont été choisis pour être publiés dans la Revue Médicale Suisse et Primary Care.

Sex ratio bias, male aggression, and population collapse in lizards.

The adult sex ratio (ASR) is a key parameter of the demography of human and other animal populations, yet the causes of variation in ASR, how individuals respond to this variation, and how their response feeds back into population dynamics remain poorly understood. A prevalent hypothesis is that ASR is regulated by intrasexual competition, which would cause more mortality or emigration in the sex of increasing frequency. Our experimental manipulation of populations of the common lizard (Lacerta vivipara) shows the opposite effect. Male mortality and emigration are not higher under male-biased ASR. Rather, an excess of adult males begets aggression toward adult females, whose survival and fecundity drop, along with their emigration rate. The ensuing prediction that adult male skew should be amplified and total population size should decline is supported by long-term data. Numerical projections show that this amplifying effect causes a major risk of population extinction. In general, such an "evolutionary trap" toward extinction threatens populations in which there is a substantial mating cost for females, and environmental changes or management practices skew the ASR toward males.

Determinants of male fitness: disentangling intra- and inter-sexual selection.

Both intra- and inter-sexual selection may crucially determine a male's fitness. Their interplay, which has rarely been experimentally investigated, determines a male's optimal reproductive strategy and thus is of fundamental importance to the understanding of a male's behaviour. Here we investigated the relative importance of intra- and inter-sexual selection for male fitness in the common lizard. We investigated which male traits predict a male's access to reproduction allowing for both selective pressures and comparing it with a staged mating experiment excluding all types of intra-sexual selection. We found that qualitatively better males were more likely to reproduce and that sexual selection was two times stronger when allowing for both selective pressures, suggesting that inter- and intra-sexual selection determines male fitness and confirming the existence of multi-factorial sexual selection. Consequently, to optimize fitness, males should trade their investment between the traits, which are important for inter- and intra-sexual selection.

Lifetime and intergenerational fitness consequences of harmful male interactions for female lizards.

Male mating behaviors harmful to females have been described in a wide range of species. However, the direct and indirect fitness consequences of harmful male behaviors have been rarely quantified for females and their offspring, especially for long-lived organisms under natural conditions. Here, lifetime and intergenerational consequences of harmful male interactions were investigated in female common lizards (Lacerta vivipara) using field experiments. We exposed females to male harm by changing the population sex ratio from a normal female-biased to an experimental male-biased sex ratio during the first experimental year. Thereafter, females and their first generation of offspring were monitored during two additional years in a common garden with a female-biased sex ratio. We found strong immediate fitness costs and lower lifetime reproductive success in females subjected to increased male exposure. The immediate fitness costs were partly mitigated by direct compensatory responses after exposure to male excess, but not by indirect benefits through offspring growth, offspring survival, or mating success of offspring. These results support recent empirical findings showing that the direct costs of mating are not outweighed by indirect benefits.

Experimental enhancement of corticosterone levels positively affects subsequent male survival.

Corticosterone is an important hormone of the stress response that regulates physiological processes and modifies animal behavior. While it positively acts on locomotor activity, it may negatively affect reproduction and social activity. This suggests that corticosterone may promote behaviors that increase survival at the cost of reproduction. In this study, we experimentally investigate the link between corticosterone levels and survival in adult common lizards (Lacerta vivipara) by comparing corticosterone-treated with placebo-treated lizards. We experimentally show that corticosterone enhances energy expenditure, daily activity, food intake, and it modifies the behavioral time budget. Enhanced appetite of corticosterone-treated individuals compensated for increased energy expenditure and corticosterone-treated males showed increased survival. This suggests that corticosterone may promote behaviors that reduce stress and it shows that corticosterone per se does not reduce but directly or indirectly increases longer-term survival. This suggests that the production of corticosterone as a response to a stressor may be an adaptive mechanism that even controls survival.

"Vedo il male e non lo posso schivare" : le rime di Antonio Brocardo tra classicismi e polemiche

Antonio Brocardo è ricordato per essere entrato in polemica con Pietro Bembo, suscitando clamore e indignazione. Le fonti antiche sulla vita del Bembo lo descrivono come un folle intento a distruggere qualcosa che non riusciva bene a comprendere Vitaliani lo definisce, nel titolo della sua monografia del 1902 (l'unica fino ad ora dedicata al poeta), «vittima del bembismo», probabilmente risentendo dei pesanti giudizi sul cardinale già presenti in Leopardi e poi nel De Sanctis. Eppure, già a partire da Croce, si cerca di ricostruire in maniera meno pregiudizievole la figura del poeta veneziano, considerando più da vicino i testi pervenuti. Ci si trova, però, di fronte ad uno scarto imponente: la tradizione lo vuole opposto al bembismo, mentre la lirica brocardiana non sembra per molti aspetti differenziarsi così platealmente dal canone bembesco, a giudizio di molte storie letterarie. Questa nuova edizione mira: a ricostruire scrupolosamente la biografia del poeta, l'ambiente frequentato ed i rapporti con altri poeti/intellettuali del suo tempo; a fare finalmente chiarezza sulle polemiche che videro il giovane veneziano come protagonista, a partire dalle fonti contemporanee (correggendo quanto riportato dalle biografìe del Bembo o dalle storie letterarie); a fornire un adeguato commento alle sue rime, dopo aver ristabilito un sicuro testo critico; a fare maggior chiarezza sul rapporto tra Brocardo ed il furbesco letterario; a collocare il poeta in una ben determinata fase del petrarchismo.

Sweet and low and Schubert songs for male chorus

Digitoituna vain levyn B-puoli, "Schubert Songs for Male Chorus".