Sequence and structural relationships in the cytokine family

The sequences of nine different cytokines, growth hormone, and prolactin have been aligned and their secondary structure predicted. The alignment reveals that each exon has a characteristic sequence pattern shared by all cytokines. The most striking sequence similarity is observed in exon 4, where the residue pair Phe-Leu is conserved in many cytokines. In addition, there are discreet homologous regions between two specific growth factors, including a high degree of homology between granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 3 (IL-3). The secondary structure analysis predicts that exon 3 of all cytokines has an antiparallel helix-turn-helix motif, which is likely to form the central helical segments of a four -helical bundle-type structure. Based on the secondary structure and the disulfidebonding pattern, the topological connectivity for a number of cytokines has been predicted.     

Phosphorylation of ligand-gated ion channels: a possible mode of synaptic plasticity.

Most neurotransmitter receptors examined to date have been shown either to be regulated by protein phosphorylation or to contain consensus sequences for phosphorylation by protein kinases. Neurotransmitter receptors that mediate rapid synaptic transmission in the nervous system are the ligand-gated ion channels and include the nicotinic acetylcholine receptors of muscle and nerve and the excitatory and inhibitory amino acid receptors: the glutamate, GABAA, and glycine receptors. These receptors are multimeric proteins composed of homologous subunits which each span the membrane several times and contain a large intracellular loop that is a mosaic of consensus sites for protein phosphorylation. Recent evidence has suggested that extracellular signals released from the presynaptic neuron, such as neurotransmitters and neuropeptides as well as an extracellular matrix protein, regulate the phosphorylation of ligand-gated ion channels. The functional effects of phosphorylation are varied and include the regulation of receptor desensitization rate, subunit assembly, and receptor aggregation at the synapse. These results suggest that phosphorylation of neurotransmitter receptors represents a major mechanism in the regulation of their function and may play an important role in synaptic plasticity.     

Safety and immunogenicity of 2-dose heterologous Ad26.ZEBOV,MVA-BN-Filo Ebola vaccination in children and adolescents in Africa: A randomised,placebo-controlled,multicentre Phase II clinical trial

BackgroundReoccurring Ebola outbreaks in West and Central Africa have led to serious illness and death in thousands of adults and children. The objective of this study was to assess safety, tolerability, and immunogenicity of the heterologous 2-dose Ad26.ZEBOV, MVA-BN-Filo vaccination regimen in adolescents and children in Africa.Methods and findingsIn this multicentre, randomised, observer-blind, placebo-controlled Phase II study, 131 adolescents (12 to 17 years old) and 132 children (4 to 11 years old) were enrolled from Eastern and Western Africa and randomised 5:1 to receive study vaccines or placebo. Vaccine groups received intramuscular injections of Ad26.ZEBOV (5 × 10¹⁰ viral particles) and MVA-BN-Filo (1 × 10⁸ infectious units) 28 or 56 days apart; placebo recipients received saline. Primary outcomes were safety and tolerability. Solicited adverse events (AEs) were recorded until 7 days after each vaccination and serious AEs (SAEs) throughout the study. Secondary and exploratory outcomes were humoral immune responses (binding and neutralising Ebola virus [EBOV] glycoprotein [GP]-specific antibodies), up to 1 year after the first dose. Enrolment began on February 26, 2016, and the date of last participant last visit was November 28, 2018. Of the 263 participants enrolled, 217 (109 adolescents, 108 children) received the 2-dose regimen, and 43 (20 adolescents, 23 children) received 2 placebo doses. Median age was 14.0 (range 11 to 17) and 7.0 (range 4 to 11) years for adolescents and children, respectively. Fifty-four percent of the adolescents and 51% of the children were male. All participants were Africans, and, although there was a slight male preponderance overall, the groups were well balanced. No vaccine-related SAEs were reported; solicited AEs were mostly mild/moderate. Twenty-one days post-MVA-BN-Filo vaccination, binding antibody responses against EBOV GP were observed in 100% of vaccinees (106 adolescents, 104 children). Geometric mean concentrations tended to be higher after the 56-day interval (adolescents 13,532 ELISA units [EU]/mL, children 17,388 EU/mL) than the 28-day interval (adolescents 6,993 EU/mL, children 8,007 EU/mL). Humoral responses persisted at least up to Day 365.A limitation of the study is that the follow-up period was limited to 365 days for the majority of the participants, and so it was not possible to determine whether immune responses persisted beyond this time period. Additionally, formal statistical comparisons were not preplanned but were only performed post hoc.ConclusionsThe heterologous 2-dose vaccination was well tolerated in African adolescents and children with no vaccine-related SAEs. All vaccinees displayed anti-EBOV GP antibodies after the 2-dose regimen, with higher responses in the 56-day interval groups. The frequency of pyrexia after vaccine or placebo was higher in children than in adolescents. These data supported the prophylactic indication against EBOV disease in a paediatric population, as licenced in the EU.Trial registrationClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT02564523","term_id":"NCT02564523"}}NCT02564523.

Zacchaeus Anywaine and co-workers study safety and immunogenicity of an Ebola vaccine among children and adolescents across four African countries.     

Ecological consequences of altered hydrological regimes in fragmented ecosystems in southern Australia: Impacts and possible management responses

Abstract Although the potential impacts of rising water tables and secondary salinization on agricultural land in southern Australia have been recognized for some time, it is only recently that the impacts on native vegetation have been considered. Despite the likely extent and severity of the problem, no comprehensive approach to assessing the impact of salinity upon native vegetation has been attempted to date. In the present paper, we discuss the causes and impacts of rising water tables and dryland salinity, assess the levels of risk in different ecosystem types and consider the possibilities for the maintenance of biodiversity and ecosystem function in vegetation at risk. We examine the salinity risk to woodland vegetation in the Western Australian (WA) wheatbelt, and consider both broad‐scale context and finer‐scale variation within individual patches of vegetation. From this information, we develop a set of conceptual models of the potential impacts of shallow saline water tables on ecosystem structure and processes in remnant vegetation in agricultural areas, particularly in the WA wheatbelt. First, we suggest that fine‐scale variability in surface topography and soil characteristics may play an important role in limiting the impacts of rising saline water tables. The outcome will depend on the interaction of the heterogeneity of the impact, species distribution in relation to small‐scale environmental heterogeneity and variation in species response to hydrological change. Second, we suggest that shallow saline water tables can be considered to cause an ‘edge effect’, which moves inwards from the edge of remnants of native vegetation. Finally, we consider how saline surface flows exacerbate the effects of shallow saline water tables and hasten vegetation decline in remnant areas. We put these models forward as hypotheses to be tested in different situations. We contrast the situation of secondary salinization in Australian vegetation with that of naturally saline systems in Australia and elsewhere, and suggest that these systems may provide important signposts toward developing management approaches for vegetation at risk. In conclusion, we consider the need to set priorities for the protection and restoration of natural vegetation at risk from altered hydrology, based on an assessment of relative threat and probability of persistence or recovery. We highlight the urgency for action that protects native vegetation from the increasing risks of rising water tables.     

Chondroitin sulfate B exerts its inhibitory effect on secondary lymphoid tissue chemokine (SLC) by binding to the C-terminus of SLC

We previously reported that certain glycosaminoglycans (GAGs) bind secondary lymphoid tissue chemokine (SLC, CCL21) and that the SLC-binding GAGs, including chondroitin sulfate B (CS B), negatively modulate the function of SLC, although the mechanism remains unknown [J. Biol. Chem. 276 (2001) 5228]. To gain insight into the mechanism of inhibition, we used a C-terminally truncated SLC (SLC-T) that lacked clusters of basic amino acid residues that have been implicated in GAG binding. While SLC-T failed to bind any GAGs, it induced prominent intracellular Ca(2+) mobilization in CC chemokine receptor (CCR) 7-expressing cells, as did wild-type SLC. However, the SLC-T-induced Ca(2+) influx was not inhibited by CS B, unlike the SLC-induced Ca(2+) influx. These results demonstrate the requirement of the C-terminus of SLC for the inhibition of chemokine responses by CS B; that is, CS B exerts its inhibitory effect by binding to the C-terminus of SLC, thus defining the mode of action of CS B on certain chemokines.     

Stepping up melanocytes to the challenge of UV exposure

Exposure to solar ultraviolet radiation (UV) is the main etiological factor for skin cancer, including melanoma. Cutaneous pigmentation, particularly eumelanin, afforded by melanocytes is the main photoprotective mechanism, as it prevents UV-induced DNA damage in the epidermis. Therefore, maintaining genomic stability of melanocytes is crucial for prevention of melanoma, as well as keratinocyte-derived basal and squamous cell carcinoma. A critical independent factor for preventing melanoma is DNA repair capacity. The response of melanocytes to UV is mediated mainly by a network of paracrine factors that not only activate melanogenesis, but also DNA repair, anti-oxidant, and survival pathways that are pivotal for maintenance of genomic stability and prevention of malignant transformation or apoptosis. However, little is known about the stress response of melanocytes to UV and the regulation of DNA repair pathways in melanocytes. Unraveling these mechanisms might lead to strategies to prevent melanoma, as well as non-melanoma skin cancer.     

Significance of the melanocortin 1 receptor in the DNA damage response of human melanocytes to ultraviolet radiation

Activation of the melanocortin 1 receptor (MC1R) by α‐melanocortin (α‐MSH) stimulates eumelanin synthesis and enhances repair of ultraviolet radiation (UV)‐induced DNA damage. We report on the DNA damage response (DDR) of human melanocytes to UV and its enhancement by α‐MSH. α‐MSH up‐regulated the levels of XPC, the enzyme that recognizes DNA damage sites, enhanced the UV‐induced phosphorylation of the DNA damage sensors ataxia telangiectasia and Rad3‐related (ATR) and ataxia telangiectasia mutated (ATM) and their respect‐ive substrates checkpoint kinases 1 and 2, and increased phosphorylated H2AX (γH2AX) formation. These effects required functional MC1R and were absent in melanocytes expressing loss of function (LOF) MC1R. The levels of wild‐type p53‐induced phosphatase 1 (Wip1), which dephosphorylates γH2AX, correlated inversely with γH2AX. We propose that α‐MSH increases UV‐induced γH2AX to facilitate formation of DNA repair complexes and repair of DNA photoproducts, and LOF of MC1R compromises the DDR and genomic stability of melanocytes.     

Real-time dissolved carbon dioxide monitoring II: Surface aeration intensification for efficient CO2 removal in shake flasks and mini-bioreactors leads to superior growth and recombinant protein yields

Mass transfer is known to play a critical role in bioprocess performance and henceforth monitoring dissolved O₂ (DO) and dissolved CO₂ (dCO₂) is of paramount importance. At bioreactor level these parameters can be monitored online and can be controlled by sparging air/oxygen or stirrer speed. However, traditional small-scale systems such as shake flasks lack real time monitoring and also employ only surface aeration with additional diffusion limitations imposed by the culture plug. Here we present implementation of intensifying surface aeration by sparging air in the headspace of the reaction vessel and real-time monitoring of DO and dCO₂ in the bioprocesses to evaluate the impact of intensified surface aeration. We observed that sparging air in the headspace allowed us to keep dCO₂ at low level, which significantly improved not only biomass growth but also protein yield. We expect that implementing such controlled smart shake flasks can minimize the process development gap which currently exists in shake flask level and bioreactor level results.     

Low dose IL-15 induces snap arming of CD44(low) T lymphocytes in the absence of antigen

It is widely accepted that naïve T cells require two signals, antigen recognition and co-simulation, to become cytotoxic over the course of 3–5 days. However, we observed that freshly isolated murine splenocytes without exposure to antigen become cytotoxic within 24 h after culture with IL-15. IL-15 is a cytokine that promotes homeostatic proliferation, maintenance and activation of memory T cells. The induced cytotoxicity, measured by anti-CD3 redirected ⁵¹Cr release, represented the combined activity of T cells regardless of their antigen specificity, and proceeded even when CD44^hi (memory-associated phenotype) CD8⁺ T cells were depleted. Cytotoxic capacity was perforin-dependent and occurred without detectable up-regulation of granzyme B or cell division. After induction, the phenotypic markers for the memory subset and for activation remained unchanged from the expression of resting T cells. Our work suggests that T cells may gain cytotoxic potential earlier than currently thought and even without TCR stimulation.