Adverse wind conditions during northward Sahara crossings increase the in‐flight mortality of Black‐tailed Godwits

Long‐distance migratory flights are predicted to be associated with higher mortality rates when individuals encounter adverse weather conditions. However, directly connecting environmental conditions experienced in‐flight with the survival of migrants has proven difficult. We studied how the in‐flight mortality of 53 satellite‐tagged Black‐tailed Godwits (Limosa limosa limosa) during 132 crossings of the Sahara Desert, a major geographical barrier along their migration route between The Netherlands and sub‐Saharan Africa, is correlated with the experienced wind conditions and departure date during both southward and northward migration. We show that godwits experienced higher wind assistance during southward crossings, which seems to reflect local prevailing trade winds. Critically, we found that fatal northward crossings (15 deaths during 61 crossings) were associated with adverse wind conditions. Wind conditions during migration can thus directly influence vital rates. Changing wind conditions associated with global change may thus profoundly influence the costs of long‐distance migration in the future.     

The Preprotein Binding Domain of SecA Displays Intrinsic Rotational Dynamics

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Pupil Dilation Co-Varies with Memory Strength of Individual Traces in a Delayed Response Paired-Associate Task

Studies on cognitive effort have shown that pupil dilation is a reliable indicator of memory load. However, it is conceivable that there are other sources of effort involved in memory that also affect pupil dilation. One of these is the ease with which an item can be retrieved from memory. Here, we present the results of an experiment in which we studied the way in which pupil dilation acts as an online marker for memory processing during the retrieval of paired associates while reducing confounds associated with motor responses. Paired associates were categorized into sets containing either 4 or 7 items. After learning the paired associates once, pupil dilation was measured during the presentation of the retrieval cue during four repetitions of each set. Memory strength was operationalized as the number of repetitions (frequency) and set-size, since having more items per set results in a lower average recency. Dilation decreased with increased memory strength, supporting the hypothesis that the amplitude of the evoked pupillary response correlates positively with retrieval effort. Thus, while many studies have shown that “memory load” influences pupil dilation, our results indicate that the task-evoked pupillary response is also sensitive to the experimentally manipulated memory strength of individual items. As these effects were observed well before the response had been given, this study also suggests that pupil dilation can be used to assess an item’s memory strength without requiring an overt response.     

Using Manipulated Photographs to Identify Features of Streetscapes That May Encourage Older Adults to Walk for Transport

Experimental evidence of environmental features important for physical activity is challenging to procure in real world settings. The current study aimed to investigate the causal effects of environmental modifications on a photographed street''s appeal for older adults'' walking for transport. Secondly, we examined whether these effects differed according to gender, functional limitations, and current level of walking for transport. Thirdly, we examined whether different environmental modifications interacted with each other. Qualitative responses were also reported to gain deeper insight into the observed quantitative relationships. Two sets of 16 panoramic photographs of a streetscape were created, in which six environmental factors were manipulated (sidewalk evenness, traffic level, general upkeep, vegetation, separation from traffic, and benches). Sixty older adults sorted these photographs on appeal for walking for transport on a 7-point scale and reported qualitative information on the reasons for their rankings. Sidewalk evenness appeared to have the strongest influence on a street''s appeal for transport-related walking. The effect of sidewalk evenness was even stronger when the street''s overall upkeep was good and when traffic was absent. Absence of traffic, presence of vegetation, and separation from traffic also increased a street''s appeal for walking for transport. There were no moderating effects by gender or functional limitations. The presence of benches increased the streetscape''s appeal among participants who already walked for transport at least an hour/week. The protocols and methods used in the current study carry the potential to further our understanding of environment-PA relationships. Our findings indicated sidewalk evenness as the most important environmental factor influencing a street''s appeal for walking for transport among older adults. However, future research in larger samples and in real-life settings is needed to confirm current findings.     

Sex‐specific growth in chicks of the sexually dimorphic Black‐tailed Godwit

Sexual size dimorphism (SSD) is common in birds and has been linked to various selective forces. Nevertheless, the question of how and when the sexes start to differentiate from each other is poorly studied. This is a critical knowledge gap, as sex differences in growth may cause different responses to similar ecological conditions. In this study, we describe the sex‐specific growth – based on body mass and five morphometric measurements – of 56 captive Black‐tailed Godwit Limosa limosa limosa chicks raised under ad libitum food conditions, and conclude that all six growth curves are sex‐specific. Females are the larger sex in terms of body mass and skeletal body size. To test whether sex‐specific growth leads to sex‐specific susceptibility to environmental conditions, we compared the age‐specific sizes of male and female chicks in the wild with those of Black‐tailed Godwits reared in captivity. We then tested for a relationship between residual growth and relative hatching date, age, sex and habitat type in which the wild chicks were born. Early‐hatched chicks were relatively bigger and in better condition than late‐hatched chicks, but body condition and size were not affected by natal habitat type. Female chicks deviated more negatively from the sex‐specific growth curves than male chicks for body mass and total‐head length. This suggests that the growth of the larger females is more susceptible to limiting environmental conditions. On average, the deviations of wild chicks from the predicted growth curves were negative for all measurements, which suggests that conditions are limiting in the current agricultural landscape. We argue that in estimating growth curves for sexually dimorphic species, it is critical first to make accurate sex and age determinations.     

Immunological and functional characterization of Mycobacterium leprae protein antigens: an overview

A major focus of leprosy research in the last 10 years has been the identification and characterization of antigens of Mycobacterium leprae that interact with antibodies and T cells of the host's immune response. Through the combined efforts of many different laboratories, a substantial number of protein antigens have been identified and characterized. In this MicroReview we present an updated list of M. leprae protein antigens, and, with emphasis on recent developments, summarize what is known regarding their functional and immunological features.     

Unique gene organization of thioredoxin and thioredoxin reductase in Mycobacterium leprae

The thioredoxin system comprising thioredoxin (Trx), thioredoxin reductase (TR) and NADPH operates via redox-active disulphides and provides electrons for a wide variety of different metabolic processes in prokaryotic and eukaryotic cells. Thioredoxin is also a general protein disulphide reductase involved in redox regulation. In bacteria, the Trx and TR proteins previously identified were encoded by separate genes (trxA and trxB). In this study, we report a novel genomic organization of TR and Trx in mycobacteria and show that at least three modes of organization of TR and Trx genes can exist within a single bacterial genus: (i) in the majority of mycobacterial strains the genes coding for TR and Trx are located on separate sites of the genome; (ii) interestingly, in all pathogenic Mycobacterium tuberculosis complex mycobacteria both genes are found on the same locus, overlapping in one nucleotide; (iii) in the pathogen Mycobacterium leprae, TR and Trx are encoded by a single gene. Sequence analysis of the M. leprae gene demonstrated that the N-terminal part of the protein corresponds to TR and the C-terminal part to Trx. A corresponding single protein product of approximately 49 kDa was detected in cell extracts of M. leprae. These findings demonstrate the very unusual phenomenon of a single gene coding for both the substrate (thioredoxin) and the enzyme (thioredoxin reductase), which seems to be unique to M. leprae.     

Subcellular localization and topology of the K88 usher FaeD in Escherichia coli

The subcellular localization of the K88 usher FaeD was studied in Escherichia coli whole ceils by using iso-pycnic sucrose density gradient centrifugation of isolated membranes, the detergents Triton X-100 and sodium lauryl sarcosinate and immunoblotting with a specific FaeD antiserum. Cells containing the complete K88 operon, as well as cells containing the sub-cloned faeD gene in various expression vectors, were used. Most of the FaeD was present in the outer membranes in a detergent-resistant form. Agglutination experiments with E coli cells expressing FaeD confirmed an outer membrane localization and indicated the presence of FaeD at the cell surface. Automated Edman degradation indicated that the mature FaeD contained 777 amino acid residues and confirmed that FaeD is synthesized with a rather long signal sequence of 35 amino acid residues. Twelve different FaeD–PhoA fusion proteins were prepared and characterized by nucleotide sequencing and immuno-blotting. Most of these fusion sites were located in the amino-terminal and carboxyl-terminal regions of FaeD. Six amino-terminal fusion proteins were soluble proteins in the peripiasm, whereas the other fusion proteins were associated with the outer membrane. The protease accessibility of FaeD and of the six outer membrane-bound FaeD–PhoA fusion proteins was studied using whole cells, cells with permeabilized outer membranes, and isolated membranes. Collagenase H, kallikrein, trypsin and proteinase K were used. Based on the results of these experiments and computer predictions, a model for the membrane topology of FaeD was developed in which FaeD contains a large central domain containing 24 membrane-spanning segments and two relatively large periplasmic regions, at the amino-terminal and carboxyl-terminal end of the protein, respectively.     

Mass Spectrometric Identification and Quantification of Hemorphins Extracted from Human Adrenal and Pheochromocytoma Tissue

Abstract: The hemorphins are a family of recently identified opioid receptor binding peptides derived from the proteolytic processing of the β, γ, δ, and ε chains of hemoglobin. They have previously been identified at high concentration in human pituitary glands and in the CSF of patients with cerebral bleeding. Hemorphins are potent inhibitors of angiotensin converting enzyme and therefore possibly have a role to play in blood pressure regulation. We report the presence of four hemorphin peptides in extracts of normal adrenal tissue and in pheochromocytoma tumors. The hemorphins were quantified and structurally characterized using mass spectrometry. High concentrations of hemorphins were found in all samples, comparable with the levels reported in the literature for pituitary and brain tissue.     

Psychosocial and Environmental Correlates of Walking,Cycling, Public Transport and Passive Transport to Various Destinations in Flemish Older Adolescents

Background

Active transport is a convenient way to incorporate physical activity in adolescents’ daily life. The present study aimed to investigate which psychosocial and environmental factors are associated with walking, cycling, public transport (train, tram, bus, metro) and passive transport (car, motorcycle, moped) over short distances (maximum eight kilometres) among older adolescents (17–18 years), to school and to other destinations.

Methods

562 older adolescents completed an online questionnaire assessing socio-demographic variables, psychosocial variables, environmental variables and transport to school/other destinations. Zero-inflated negative binomial regression models were performed.

Results

More social modelling and a higher residential density were positively associated with walking to school and walking to other destinations, respectively. Regarding cycling, higher self-efficacy and a higher social norm were positively associated with cycling to school and to other destinations. Regarding public transport, a higher social norm, more social modelling of siblings and/or friends, more social support and a higher land use mix access were positively related to public transport to school and to other destinations, whereas a greater distance to school only related positively to public transport to school. Regarding passive transport, more social support and more perceived benefits were positively associated with passive transport to school and to other destinations. Perceiving less walking and cycling facilities at school was positively related to passive transport to school only, and more social modelling was positively related to passive transport to other destinations.

Conclusions

Overall, psychosocial variables seemed to be more important than environmental variables across the four transport modes. Social norm, social modelling and social support were the most consistent psychosocial factors which indicates that it is important to target both older adolescents and their social environment in interventions promoting active transport. Walking or cycling together with siblings or friends has the potential to increase social norm, social modelling and social support towards active transport.