Impaired flight ability--a cost of reproduction in female blue tits

When prey are attacked by predators, escape ability has an obvious influence on the probability of survival. Laboratory studieshave suggested that flight performance of female birds mightbe affected by egg production. This is the first study of changesin take-off ability, and thus potentially in predation risk,during reproduction in wild birds. We trapped individual maleand female blue tits repeatedly during the breeding season.Females were 14% heavier and flew 20% slower (probably as aconsequence of a lower ratio of flight muscle to body mass)during the egg-laying period than after the eggs had hatched.However, flight muscle size did not change to compensate for changes in body mass over this period. In contrast, males showedno changes in either body mass, muscle size, or flight abilityover the same period. Furthermore, the impairment of flightin females increased with the proportion of the clutch thathad been laid, an effect that was independent of body mass and muscle size. This indicates that egg production causes additional physiological changes in the female body that produce impairedlocomotor performance. We suggest that courtship feeding offemale blue tits by their mates might reduce predation riskduring the period when female take-off ability is impairedby reducing the time females have to spend foraging and thusreducing the time they are exposed to increased predation.     

Changes in cerebral blood flow after stereotactic thalamotomy

Regional cerebral blood flow (rCBF), a parameter of neuronal activity in the brain, was measured by the 133Xe inhalation method in 43 patients undergoing stereotactic thalamotomy. A postoperative flow reduction of about 2% in the operated hemisphere was found, persisting in further measurements performed after a year. There was no consistent change in the pattern of regional flow distribution. The results indicate a diminished level of activity in the hemisphere subjected to thalamotomy, but the change could not be linked to any specific area or function.     

Phylogenetic analysis of 1.5 Mbp and platypus EST data refute the Marsupionta hypothesis and unequivocally support Monotremata as sister group to Marsupialia/Placentalia

The extant mammalian groups Monotremata, Marsupialia and Placentalia are, according to the 'Theria' hypothesis, traditionally classified into two subclasses. The subclass Prototheria includes the monotremes and subclass Theria marsupials and placental mammals. Based on some morphological and molecular data, an alternative proposition, the Marsupionta hypothesis, favours a sister group relationship between monotremes and marsupials to the exclusion of placental mammals. Phylogenetic analyses of single genes and even multiple gene alignments have not yet been able to conclusively resolve this basal mammalian divergence. We have examined this problem using one data set composed of expressed sequence tags (EST) and another containing 1 510 509 nucleotide (nt) sites from 1358 inferred cDNA genomic sequences. All analyses of the concatenated sequences unambiguously supported the Theria hypothesis. The Marsupionta hypothesis was rejected with high statistical confidence from both data sets. In spite of the strong support for Theria, a non-negligible number of single genes supported either of the two alternative hypotheses. The divergence between monotremes and therian mammals was estimated to have taken place 168–178 Mya, a dating compatible with the fossil record. Considering the long common evolutionary branch of therians, it is surprising that sequence data from many thousand amino acid sites were needed to conclusively resolve their relationship to monotremes. This finding draws attention to other mammalian divergences that have been taken as unequivocally settled based on much smaller alignments. EST data provide a comprehensive random sample of protein coding sequences and an economic way to produce large amounts of data for phylogenetic analysis of species for which genomic sequences are not yet available.     

Lack of Melanopsin Is Associated with Extreme Weight Loss in Mice upon Dietary Challenge

Metabolic disorders have been established as major risk factors for ocular complications and poor vision. However, little is known about the inverse possibility that ocular disease may cause metabolic dysfunction. To test this hypothesis, we assessed the metabolic consequences of a robust dietary challenge in several mouse models suffering from retinal mutations. To this end, mice null for melanopsin (Opn4^-/-), the photopigment of intrinsically photosensitive retinal ganglion cells (ipRGCs), were subjected to five weeks of a ketogenic diet. These mice lost significantly more weight than wild-type controls or mice lacking rod and cone photoreceptors (Pde6b^rd1/rd1). Although ipRGCs are critical for proper circadian entrainment, and circadian misalignment has been implicated in metabolic pathology, we observed no differences in entrainment between Opn4^-/- and control mice. Additionally, we observed no differences in any tested metabolic parameter between these mouse strains. Further studies are required to establish the mechanism giving rise to this dramatic phenotype observed in melanopsin-null mice. We conclude that the causality between ocular disease and metabolic disorders merits further investigation due to the popularity of diets that rely on the induction of a ketogenic state. Our study is a first step toward understanding retinal pathology as a potential cause of metabolic dysfunction.     

Till Death Do Us Part: Stable Sponge-Bacteria Associations under Thermal and Food Shortage Stresses

Sporadic mass mortality events of Mediterranean sponges following periods of anomalously high temperatures or longer than usual stratification of the seawater column (i.e. low food availability) suggest that these animals are sensitive to environmental stresses. The Mediterranean sponges Ircinia fasciculata and I. oros harbor distinct, species-specific bacterial communities that are highly stable over time and space but little is known about how anomalous environmental conditions affect the structure of the resident bacterial communities. Here, we monitored the bacterial communities in I. fasciculata (largely affected by mass mortalities) and I. oros (overall unaffected) maintained in aquaria during 3 weeks under 4 treatments that mimicked realistic stress pressures: control conditions (13°C, unfiltered seawater), low food availability (13°C, 0.1 µm-filtered seawater), elevated temperatures (25°C, unfiltered seawater), and a combination of the 2 stressors (25°C, 0.1 µm-filtered seawater). Bacterial community structure was assessed using terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA gene sequences and transmission electron microscopy (TEM). As I. fasciculata harbors cyanobacteria, we also measured chlorophyll a (chl a) levels in this species. Multivariate analysis revealed no significant differences in bacterial T-RFLP profiles among treatments for either host sponge species, indicating no effect of high temperatures and food shortage on symbiont community structure. In I. fasciculata, chl a content did not significantly differ among treatments although TEM micrographs revealed some cyanobacteria cells undergoing degradation when exposed to both elevated temperature and food shortage conditions. Arguably, longer-term treatments (months) could have eventually affected bacterial community structure. However, we evidenced no appreciable decay of the symbiotic community in response to medium-term (3 weeks) environmental anomalies purported to cause the recurrent sponge mortality episodes. Thus, changes in symbiont structure are not likely the proximate cause for these reported mortality events.     

Soluble ACE2-mediated cell entry of SARS-CoV-2 via interaction with proteins related to the renin-angiotensin system

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Process optimization for increased yield of surface-expressed protein in Escherichia coli

The autotransporter family of Gram-negative protein exporters has been exploited for surface expression of recombinant passenger proteins. While the passenger in some cases was successfully translocated, a major problem has been low levels of full-length protein on the surface due to proteolysis following export over the cytoplasmic membrane. The aim of the present study was to increase the surface expression yield of the model protein SefA, a Salmonella enterica fimbrial subunit with potential for use in vaccine applications, by reducing this proteolysis through process design using Design of Experiments methodology. Cultivation temperature and pH, hypothesized to influence periplasmic protease activity, as well as inducer concentration were the parameters selected for optimization. Through modification of these parameters, the total surface expression yield of SefA was increased by 200 %. At the same time, the yield of full-length protein was increased by 300 %, indicating a 33 % reduction in proteolysis.     

Gender Stereotype Susceptibility

Gender affects performance on a variety of cognitive tasks, and this impact may stem from socio-cultural factors such as gender stereotyping. Here we systematically manipulated gender stereotype messages on a social cognition task on which no initial gender gap has been documented. The outcome reveals: (i) Stereotyping affects both females and males, with a more pronounced impact on females. Yet an explicit negative message for males elicits a striking paradoxical deterioration in performance of females. (ii) Irrespective of gender and directness of message, valence of stereotype message affects performance: negative messages have stronger influence than positive ones. (iii) Directness of stereotype message differentially impacts performance of females and males: females tend to be stronger affected by implicit than explicit negative messages, whereas in males this relationship is opposite. The data are discussed in the light of neural networks underlying gender stereotyping. The findings provide novel insights into the sources of gender related fluctuations in cognition and behavior.