Flight initiation distance and escape behavior in the black redstart (Phoenicurus ochruros)

There are many anti‐predatory escape strategies in animals. A well‐established method to assess escape behavior is the flight initiation distance (FID), which is the distance between prey and predator at which an animal flees. Previous studies in various species throughout the animal kingdom have shown that group size, urbanization, and distance to refuge and body mass affect FID. In most species, FID increases if body mass, group size or distance to refuge decreases. However, how age and sexual dimorphism affect FID is rather unknown. Here, we assess the escape behavior and FID of the black redstart (Phoenicurus ochruros), a small turdid passerine. When approached by a human, males initiated flights later, that is allowing a closer approach than females. Males of this species are more conspicuous, and therefore, may exhibit aposematism to deter potential predators or are less fearful than females. Additionally, juveniles fled at shorter distances and fled to lower heights than adults. Lastly, concerning escape strategy, black redstarts, unless other passerine birds, fled less often into cover, but rather onto open or elevated spots. Black redstarts are especially prone to predation by ambushing predators that might hide in cover. Hence, this species most likely has a higher chance of escaping by fleeing to an open spot rather than to a potentially risky cover.     

Gender Differences in Homicide of Neonates,Infants, and Children under 5 y in South Africa: Results from the Cross-Sectional 2009 National Child Homicide Study

BackgroundHomicide of children is a global problem. The under-5-y age group is the second largest homicide age group after 15–19 y olds, but has received little research attention. Understanding age and gender patterns is important for assisting with developing prevention interventions. Here we present an age and gender analysis of homicides among children under 5 y in South Africa from a national study that included a focus on neonaticide and infanticide.ConclusionsHomicide of children is an extreme form or consequence of violence against children. This national study provides one of the first analyses of neonaticide and infanticide by age and gender and shows the failure of reproductive and mental health and social services to identify and help vulnerable mothers. Multi-sectoral prevention strategies are needed.     

The Hemagglutinin of Bat-Associated Influenza Viruses Is Activated by TMPRSS2 for pH-Dependent Entry into Bat but Not Human Cells

New World bats have recently been discovered to harbor influenza A virus (FLUAV)-related viruses, termed bat-associated influenza A-like viruses (batFLUAV). The internal proteins of batFLUAV are functional in mammalian cells. In contrast, no biological functionality could be demonstrated for the surface proteins, hemagglutinin (HA)-like (HAL) and neuraminidase (NA)-like (NAL), and these proteins need to be replaced by their human counterparts to allow spread of batFLUAV in human cells. Here, we employed rhabdoviral vectors to study the role of HAL and NAL in viral entry. Vectors pseudotyped with batFLUAV-HAL and -NAL were able to enter bat cells but not cells from other mammalian species. Host cell entry was mediated by HAL and was dependent on prior proteolytic activation of HAL and endosomal low pH. In contrast, sialic acids were dispensable for HAL-driven entry. Finally, the type II transmembrane serine protease TMPRSS2 was able to activate HAL for cell entry indicating that batFLUAV can utilize human proteases for HAL activation. Collectively, these results identify viral and cellular factors governing host cell entry driven by batFLUAV surface proteins. They suggest that the absence of a functional receptor precludes entry of batFLUAV into human cells while other prerequisites for entry, HAL activation and protonation, are met in target cells of human origin.     

Study of relationship among species ofVibrio,Photobacterium, and terrestrial enterobacteria by an immunological comparison of glutamine synthetase and superoxide dismutase

The amino acid sequence divergence of glutamine synthetase (GS) from species ofVibrio, Photobacterium, Aeromonas, Escherichia, Salmonella, Citrobacter, Enterobacter, Serratia, Proteus, Erwinia, Xenorhabdus, andPlesiomonas was determined by quantitative microcomplement fixation, using antisera to GS fromVibrio alginolyticus andEscherichia coli. A similar study was performed with superoxide dismutase (SOD), using antiserum to the enzyme fromV. alginolyticus. A comparison of the results for GS and SOD, relative to the enzymes fromV. alginolyticus, as well as a comparison of these data with the results of previous ribosomal RNA (rRNA)/DNA homology studies indicated a high degree of congruence (correlation coefficients≥0.9). The results with both enzymes suggested four major groupings among these genera: (i)Vibrio, (ii)Photobacterium, (iii)Aeromonas, (iv) a large and heterogeneous group which included the peritrichously flagellated terrestrial enterobacteria.     

A constituent of green tea, epigallocatechin-3-gallate, activates endothelial nitric oxide synthase by a phosphatidylinositol-3-OH-kinase-, cAMP-dependent protein kinase-, and Akt-dependent pathway and leads to endothelial-dependent vasorelaxation

Epidemiological studies suggest that tea catechins may reduce the risk of cardiovascular disease, but the mechanisms of benefit have not been determined. The objective of the present study was to investigate the effects of epigallocatechin-3-gallate (EGCG), the major constituent of green tea, on vasorelaxation and on eNOS expression and activity in endothelial cells. EGCG (1-50 microm) induced dose-dependent vasodilation in rat aortic rings. Vasodilation was abolished by pretreatment with Ng-nitro L-arginine methyl ester. In bovine aortic endothelial cells, EGCG increased endothelial nitric oxide (eNOS) activity dose-dependently after 15 min. Treatment with EGCG induced a sustained activation of Akt, ERK1/2, and eNOS Ser1179 phosphorylation. Inhibition of extracellular signal-regulated kinase (ERK)1/2 had no influence on eNOS activity or Ser1179 phosphorylation. Simultaneous treatment of cells with selective inhibitors for cAMP-dependent protein kinase (PKA) and Akt completely prevented the increase in eNOS activity by EGCG after 15 min, indicating that both kinases act in concert. Specific phosphatidylinositol-3-OH-kinase inhibitors yielded identical results. Akt inhibition prevented eNOS Ser1179 phosphorylation, whereas inhibition of PKA did not influence Akt and eNOS Ser1179 phosphorylation. Pretreatment of endothelial cells with EGCG for 4 h markedly enhanced the increase in eNOS activity stimulated by Ca-ionomycin, suggesting that Akt accounts for prolonged eNOS activation. Treatment of cells for 72 h with EGCG did not change eNOS protein levels. Our results indicate that EGCG-induced endothelium-dependent vasodilation is primarily based on rapid activation of eNOS by a phosphatidylinositol 3-kinase-, PKA-, and Akt-dependent increase in eNOS activity, independently of an altered eNOS protein content.     

Characterization of the interaction of interleukin-8 with hyaluronan, chondroitin sulfate, dermatan sulfate and their sulfated derivatives by spectroscopy and molecular modeling

The interactions between glycosaminoglycans (GAGs), important components of the extracellular matrix, and proteins such as growth factors and chemokines play critical roles in cellular regulation processes. Therefore, the design of GAG derivatives for the development of innovative materials with bio-like properties in terms of their interaction with regulatory proteins is of great interest for tissue engineering and regenerative medicine. Previous work on the chemokine interleukin-8 (IL-8) has focused on its interaction with heparin and heparan sulfate, which regulate chemokine function. However, the extracellular matrix contains other GAGs, such as hyaluronic acid (HA), dermatan sulfate (DS) and chondroitin sulfate (CS), which have so far not been characterized in terms of their distinct molecular recognition properties towards IL-8 in relation to their length and sulfation patterns. NMR and molecular modeling have been in great part the methods of choice to study the structural and recognition properties of GAGs and their protein complexes. However, separately these methods have challenges to cope with the high degree of similarity and flexibility that GAGs exhibit. In this work, we combine fluorescence spectroscopy, NMR experiments, docking and molecular dynamics simulations to study the configurational and recognition properties of IL-8 towards a series of HA and CS derivatives and DS. We analyze the effects of GAG length and sulfation patterns in binding strength and specificity, and the influence of GAG binding on IL-8 dimer formation. Our results highlight the importance of combining experimental and theoretical approaches to obtain a better understanding of the molecular recognition properties of GAG-protein systems.