Regulation of middle cerebral artery blood velocity during recovery from dynamic exercise in humans.

We sought to examine the regulation of cerebral blood flow during 10 min of recovery from mild, moderate, and heavy cycling exercise by measuring middle cerebral artery blood velocity (MCA V). Transfer function analyses between changes in arterial blood pressure and MCA V were used to assess the frequency components of dynamic cerebral autoregulation (CA). After mild and moderate exercise, the decreases in mean arterial pressure (MAP) and mean MCA V (MCA Vm) were small. However, following heavy exercise, MAP was rapidly and markedly reduced, whereas MCA Vm decreased slowly (-23 +/- 4 mmHg and -4 +/- 1 cm/s after 1 min for MAP and MCA Vm, respectively; means +/- SE). Importantly, for each workload, the normalized low-frequency transfer function gain between MAP and MCA Vm remained unchanged from rest to exercise and during recovery, indicating a maintained dynamic CA. Similar results were found for the systolic blood pressure and systolic MCA V relationship. In contrast, the normalized low-frequency transfer function gain between diastolic blood pressure and diastolic MCA V (MCA Vd) increased from rest to exercise and remained elevated in the recovery period (P < 0.05). However, MCA Vd was quite stable on the cessation of exercise. These findings suggest that MCA V is well maintained following mild to heavy dynamic exercise. However, the increased transfer function gain between diastolic blood pressure and MCA Vd suggests that dynamic CA becomes less effective in response to rapid decreases in blood pressure during the initial 10 min of recovery from dynamic exercise.     

Cytochemical localization of glycogen in Chlamydia trachomatis inclusions.

The origin and distribution of glycogen in inclusions of Chlamydia trachomatis were demonstrated with silver proteinate stain for electron microscopy. Glycogen particles were detected in all developmental stages of C. trachomatis, as well as free in the inclusions. Intrachlamydial glycogen was most common in elementary bodies but was also detected in intermediate forms and reticulate bodies (RBs). Abnormal divisions and breakdown of cytoplasmic membranes were common in RBs. Cytoplasmic contents, including glycogen particles, were released into the inclusions after rupture of the outer membranes of abnormal RBs and intermediate forms. From these observations, we conclude that glycogen in inclusions of C. trachomatis originates in the organisms themselves.     

Impact of engagement of FcepsilonRI and CC chemokine receptor 1 on mast cell activation and motility

CC chemokines participate in the recruitment and activation of immune cells through CC chemokine receptors (CCRs). Here, we report that cross-talk between CCR1-mediated signaling pathway and FcepsilonRI-mediated signaling pathway affects degranulation positively but affects chemotaxis of mast cells adversely. Costimulation via FcepsilonRI engagement with IgE/antigen and CCR1 engagement with recombinant human CCL3 synergistically enhanced degranulation in rat basophilic leukemia-2H3 cells expressing human CCR1 (RBL-CCR1). Interestingly, FcepsilonRI engagement inhibited CCL3-mediated chemotaxis and membrane ruffling of RBL-CCR1 cells. Small GTP-binding proteins of the Rho family, Rac, Cdc42, and Rho control chemotaxis by mediating the reorganization of the actin cytoskeleton. Both a Rho inhibitor C3 exoenzyme and a Rho kinase (ROCK) inhibitor Y-27632 inhibited chemotaxis of RBL-CCR1 cells toward CCL3, indicating that activation of the Rho/ROCK signaling pathway is required for the CCL3-mediated chemotaxis of the cells. Costimulation with IgE/antigen and CCL3 enhanced Rac and Cdc42 activation but decreased ROCK activation in RBL-CCR1 cells compared with that in the cells stimulated with CCL3 alone. These results suggest that costimulation via FcepsilonRI and CCR1 engagements induced 1) inhibition of membrane ruffling, 2) decreased ROCK activation, and 3) reciprocal imbalance between Small GTP-binding proteins of the Rho family, which result in the inhibition of chemotaxis of RBL-CCR1 cells. The cross-talk between FcepsilonRI-mediated signaling pathway and CCR-mediated signaling pathway would induce optimal activation and arrested chemotaxis of mast cells, thus contributing to allergic inflammation.     

Mtss1 promotes cell-cell junction assembly and stability through the small GTPase Rac1

Cell-cell junctions are an integral part of epithelia and are often disrupted in cancer cells during epithelial-to-mesenchymal transition (EMT), which is a main driver of metastatic spread. We show here that Metastasis suppressor-1 (Mtss1; Missing in Metastasis, MIM), a member of the IMD-family of proteins, inhibits cell-cell junction disassembly in wound healing or HGF-induced scatter assays by enhancing cell-cell junction strength. Mtss1 not only makes cells more resistant to cell-cell junction disassembly, but also accelerates the kinetics of adherens junction assembly. Mtss1 drives enhanced junction formation specifically by elevating Rac-GTP. Lastly, we show that Mtss1 depletion reduces recruitment of F-actin at cell-cell junctions. We thus propose that Mtss1 promotes Rac1 activation and actin recruitment driving junction maintenance. We suggest that the observed loss of Mtss1 in cancers may compromise junction stability and thus promote EMT and metastasis.     

Mapping avian distributions: the evolution of bird atlases

Capsule An increasing proportion of atlases now map patterns of abundance but they are still a minority even though they require no more input of time or fieldworkers.

Aims To examine quantitatively the evolution of bird atlas methods, from their inception to the present day, to document the most frequently used methods and to quantify temporal changes in them, and so identify broad patterns that might be of use in the planning and interpretation of future atlases.

Methods A database of over 400 atlases was compiled, and a number of variables extracted from each. Temporal trends within, and relationships between, these variables were analysed.

Results Atlases have become significantly reduced in scale over time, covering smaller areas in shorter periods of fieldwork, but at higher spatial resolutions and with increasing numbers of observers per unit area. The number of participating fieldworkers and the size of the region being covered together explain over 70% of variation between atlases in spatial resolution. The number of atlases that have mapped abundance or relative abundance, rather than simply occurrence (presence/absence) or breeding status, has increased significantly over time but remains relatively small. However, such atlases were no more expensive in terms of length of the fieldwork or preparation periods or the number of observers deployed per unit area. There is evidence of a sharp decline in the number of new bird atlases being initiated.

Conclusions There have been significant changes in the way atlas surveys are undertaken, but no standardized method has evolved. This leads to flexibility that allows atlas surveys to be undertaken over areas varying by six orders of magnitude using numbers of observers that vary by five orders of magnitude.     

cDNA cloning of human oxysterol-binding protein and localization of the gene to human chromosome 11 and mouse chromosome 19

Cellular cholesterol metabolism is regulated primarily through sterol-mediated feedback suppression of the activity of the low-density lipoprotein receptor and several enzymes of the cholesterol biosynthetic pathway. We previously described the cloning of a rabbit cDNA for the oxysterol-binding protein (OSBP), a cytosolic protein of 809 amino acids that may participate in these regulatory events. We now use the rabbit OSBP cDNA to clone the human OSBP cDNA and 5' genomic region. Comparison of the human and rabbit OSBP sequences revealed a remarkably high degree of conservation. The cDNA sequence in the coding region showed 94% identity between the two species, and the predicted amino acid sequence showed 98% identity. The human cDNA was used to determine the chromosomal localization of the OSBP gene by Southern blot hybridization to panels of somatic cell hybrid clones containing subsets of human or mouse chromosomes and by RFLP analysis of recombinant inbred mouse strains. The OSBP locus mapped to the long arm of human chromosome 11 and the proximal end of mouse chromosome 19. Along with previously mapped genes including Ly-1 and CD20, OSBP defines a new conserved syntenic group on the long arm of chromosome 11 in the human and the proximal end of chromosome 19 in the mouse.     

Organization of the genes encoding the biosynthesis of actagardine and engineering of a variant generation system

The biosynthetic pathway of the type B lantibiotic actagardine (formerly gardimycin), produced by Actinoplanes garbadinensis ATCC31049, has been cloned, sequenced and annotated. The gene cluster contains the gene garA that encodes the actagardine prepropeptide, a modification gene garM , involved in the dehydration and cyclization of the prepeptide, several putative transporter and regulatory genes as well as a novel luciferase-like monooxygenase gene designated garO . Expression of these genes in Streptomyces lividans resulted in the production of ala(0)-actagardine while deletion of the garA gene from A. garbadinensis generated a strain incapable of producing actagardine. Actagardine production was successfully restored however, by the delivery of the plasmid pAGvarX. This plasmid contains an engineered cassette of the actagardine encoding gene garA and offers an alternative route to generating extensive libraries of actagardine variants. Using this plasmid, an alanine scanning library has been constructed and the mutants analysed. Further modifications include the removal of the novel garO gene from A. garbadinensis . Deletion of this gene resulted in the production of deoxy variants of actagardine, demonstrating that the formation of the sulfoxide group is enzyme catalysed and not a spontaneous chemical modification as previously believed.     

Effectiveness of a brief group behavioural intervention on psychological distress in young adolescent Syrian refugees: A randomised controlled trial

BackgroundMillions of young adolescents in low- and middle-income countries (LMICs) affected by humanitarian crises experience elevated rates of poor mental health. There is a need for scalable programs that can improve the mental health of young adolescents. This study evaluated the effectiveness of a nonspecialist delivered group-based intervention (Early Adolescent Skills for Emotions (EASE)) to improve young adolescents’ mental health.Methods and findingsIn this single-blind, parallel, controlled trial, Syrian refugees aged 10 to 14 years in Jordan were identified through screening of psychological distress as defined by scores ≥15 on the Paediatric Symptom Scale. Participants were randomised to either EASE or enhanced usual care (EUC) involving referral to local psychosocial services (on a 1:1.6 ratio). Participants were aware of treatment allocation but assessors were blinded. Primary outcomes were scores on the Paediatric Symptom Checklist (PSC; internalising, externalising, and attentional difficulty scales) assessed at week 0, 9 weeks, and 3 months after treatment (primary outcome time point). It was hypothesised that EASE would result in greater reductions on internalising symptoms than EUC. Secondary outcomes were depression, posttraumatic stress, well-being, functioning, school belongingness, and caregivers’ parenting and mental health. Between June 2019 and January 2020, 1,842 young adolescent refugees were screened for eligibility on the basis of psychological distress. There were 520 adolescents (28.2%) who screened positive, of whom 471 (90.6%) agreed to enter the trial. Overall, 185 were assigned to EASE and 286 to EUC, and 169 and 254 were retained at 3 months for EASE and EUC, respectively. Intent-to-treat analyses indicated that at 3 months, EASE resulted in greater reduction on the PSC-internalising scale than EUC (estimated mean difference 0.69, 95% CI 0.19 to 1.19; p = 0.007; effect size, 0.38) but there were no differences for PSC-externalising (estimated mean difference 0.24, 95% CI −0.43 to 0.91; p = 0.49; effect size, −0.10), PSC-attentional problem (estimated mean difference −0.01, 95% CI −0.51 to 0.54; p = 0.97; effect size, −0.01) scores, or on depression, posttraumatic stress, well-being, functioning, or school belongingness. Relative to EUC, caregivers in EASE had less psychological distress (estimated mean difference 1.95, 95% CI 0.71 to 3.19; p = 0.002) and inconsistent disciplinary parenting (mean difference 1.54, 95% CI 1.03 to 2.05; p < 0.001). Secondary analyses that (a) focused on adolescents with probable internalising disorders; (b) completed the 3-month assessment; and (c) controlled for trauma exposure did not alter the primary results. Mediation analysis indicated that for caregivers in the EASE condition, reduction in inconsistent disciplinary parenting was associated with reduced attentional (β = 0.11, SE 0.07; 95% CI 0.003, 0.274) and internalising (β = 0.11, SE 0.07; 95% CI 0.003, 0.274) problems in their children. No adverse events were attributable to the intervention. A limitation was that EUC was not matched to EASE in terms of facilitator attention or group involvement.ConclusionsEASE led to reduced internalising problems in young refugee adolescents and was associated with reduced distress and less inconsistent disciplinary parenting in caregivers. This intervention has the potential as a scalable intervention to mitigate young adolescents’ emotional difficulties in LMIC.Trial registrationProspectively registered at Australian and New Zealand Clinical Trials Registry: ACTRN12619000341123.

In a randomized controlled trial, Richard A. Bryant and colleagues study the effectiveness of the Early Adolescent Skills for Emotions (EASE) intervention to improve the mental health of Syrian refugees aged 10-14 years living in Jordan.     

Dissection and Mounting of Drosophila Pupal Eye Discs

The Drosophila melanogaster eye disc is a powerful system that can be used to study many different biological processes. It contains approximately 800 separate eye units, termed ommatidia¹. Each ommatidium contains eight neuronal photoreceptors that develop from undifferentiated cells following the passage of the morphogenetic furrow in the third larval instar². Following the sequential differentiation of the photoreceptors, non-neuronal cells develop, including cone and pigment cells, along with mechanosensory bristle cells³. Final differentiation processes, including the structured arrangement of all the ommatidial cell types, programmed cell death of undifferentiated cell types and rhodopsin expression, occurs through the pupal phase^4-7. This technique focuses on manipulating the pupal eye disc, providing insight and instruction on how to dissect the eye disc during the pupal phase, which is inherently more difficult to perform than the commonly dissected third instar eye disc. This technique also provides details on immunostaining to allow the visualization of various proteins and other cell components.