Harmonine, a defence compound from the harlequin ladybird, inhibits mycobacterial growth and demonstrates multi-stage antimalarial activity

The harlequin ladybird beetle Harmonia axyridis has been introduced in many countries as a biological control agent, but has become an invasive species threatening the biodiversity of native ladybirds. Its invasive success has been attributed to its vigorous resistance against diverse pathogens. This study demonstrates that harmonine ((17R,9Z)-1,17-diaminooctadec-9-ene), which is present in H. axyridis haemolymph, displays broad-spectrum antimicrobial activity that includes human pathogens. Antibacterial activity is most pronounced against fast-growing mycobacteria and Mycobacterium tuberculosis, and the growth of both chloroquine-sensitive and -resistant Plasmodium falciparum strains is inhibited. Harmonine displays gametocytocidal activity, and inhibits the exflagellation of microgametocytes and zygote formation. In an Anopheles stephensi mosquito feeding model, harmonine displays transmission-blocking activity

Door locks, wall stickers, fireplaces: Assemblage Theory and home (un)making in Lewisham’s temporary accommodation

This paper explores resident experiences of life in PLACE/Ladywell, a “pop‐up” social housing scheme in London providing temporary accommodation for homeless families. Specifically, we consider barriers to, and assertions of, homemaking in this temporary setting through fixtures and fittings—a door lock, wall stickers, and a fireplace. The paper utilises assemblage thinking to understand homemaking within these time‐limited and constrained circumstances. Despite their seeming banality, fixtures and fittings offer a material, politicised, and lively means of studying the attempted and thwarted production of home by residents living in PLACE/Ladywell. The absence of door locks reduces parents’ ability to maintain privacy and intimate relations; restrictions on hanging pictures and other decorative measures are circumvented by the use of wall stickers; and a defiant decorative fireplace establishes a sense of home in a temporary setting. Together, these objects constitute vital elements in negotiations between fixity and impermanence in temporary accommodation

Millisecond cryo-trapping by the spitrobot crystal plunger simplifies time-resolved crystallography

We introduce the spitrobot, a protein crystal plunger, enabling reaction quenching via cryo-trapping with millisecond time-resolution. Canonical micromesh loops are mounted on an electropneumatic piston, reactions are initiated via the liquid application method (LAMA), and finally intermediate states are cryo-trapped in liquid nitrogen. We demonstrate binding of several ligands in microcrystals of three enzymes, and trapping of reaction intermediates and conformational changes in macroscopic crystals of tryptophan synthase

Quantitative Susceptibility MRI to Detect Brain Iron in Amyotrophic Lateral Sclerosis

Purpose To investigate the whole-brain landscape of iron-related abnormalities in amyotrophic lateral sclerosis (ALS) by using the in vivo MRI technique of quantitative susceptibility mapping (QSM). Materials and Methods For this prospective study, 28 patients with ALS (mean age, 61 years; age range, 43-77 years; 18 men [mean age, 61 years; range, 43-77 years] and 10 women [mean age, 61 years; range, 47-74 years]) recruited between January 17, 2014, and September 4, 2015, and 39 matched control subjects (mean age, 61 years; age range, 39-77 years; 24 men [mean age, 62 years; range, 39-77 years] and 15 women [mean age, 59 years; range, 39-73 years]) were examined by using structural and susceptibility 3.0-T MRI techniques. Group data were cross sectionally compared with family-wise error (FWE) corrections by using voxel-based morphometry (random-field theory), cortical thickness analysis (Monte Carlo simulated), subcortical volumetry (Bonferroni-corrected Wilcoxon rank-sum testing), and QSM analysis (cluster-enhanced whole-brain permutation testing and Bonferroni-corrected rank-sum testing in regions of interest). In patients with ALS, a potential relationship between diffusion and susceptibility measurements in the corticospinal tracts (CSTs) was also examined by using Spearman rank-correlation tests. Results Conventional structural measures failed to identify atrophy in the present cohort (FWE P > .05). However, QSM identified several whole-brain abnormalities (FWE P < .05) in ALS. Regionally, higher susceptibility (expressed as means in parts per million ± standard errors of the mean) was confirmed in the motor cortex (ALS = 0.0188 ± 0.0003, control = 0.0173 ± 0.0003; P < .001), the left substantia nigra (ALS = 0.127 ± 0.004, control = 0.113 ± 0.003; P = .008), the right substantia nigra (ALS = 0.141 ± 0.005, control = 0.120 ± 0.003; P < .001), the globus pallidus (ALS = 0.086 ± 0.003, control = 0.075 ± 0.002; P = .003), and the red nucleus (ALS = 0.115 ± 0.004, control = 0.098 ± 0.003; P < .001). Lower susceptibility was found in CST white matter (ALS = -0.047 ± 0.001, control = -0.043 ± 0.001; P = .01). Nigral and pallidal QSM values were cross correlated in ALS (ρ2 = 0.42, P < .001), a phenomenon visually traceable in many individual patients. QSM in the CST in ALS also correlated with diffusion-tensor metrics in this tract (ρ2 = 0.25, P = .007). Conclusion Whole-brain MRI quantitative susceptibility mapping analysis is sensitive to tissue alterations in amyotrophic lateral sclerosis that may be relevant to pathologic changes

Q/R site interactions with the M3 helix in GluK2 kainate receptor channels revealed by thermodynamic mutant cycles

RNA editing at the Q/R site near the apex of the pore loop of AMPA and kainate receptors controls a diverse array of channel properties, including ion selectivity and unitary conductance and susceptibility to inhibition by polyamines and cis-unsaturated fatty acids, as well as subunit assembly into tetramers and regulation by auxiliary subunits. How these different aspects of channel function are all determined by a single amino acid substitution remains poorly understood; however, several lines of evidence suggest that interaction between the pore helix (M2) and adjacent segments of the transmembrane inner (M3) and outer (M1) helices may be involved. In the present study, we have used double mutant cycle analysis to test for energetic coupling between the Q/R site residue and amino acid side chains along the M3 helix. Our results demonstrate interaction with several M3 locations and particularly strong coupling to substitution for L614 at the level of the central cavity. In this location, replacement with smaller side chains completely and selectively reverses the effect of fatty acids on gating of edited channels, converting strong inhibition of wild-type GluK2(R) to nearly 10-fold potentiation of GluK2(R) L614A

The pore structure and gating mechanism of K2P channels

K2P potassium channels are important regulators of cellular excitability. This study reveals that in contrast to most other K+ channels the primary gating mechanism in the K2P channel TREK-1 does not involve opening and closure of the cytoplasmic bundle crossing, but takes place close to or within the selectivity filter

Leishmania-Induced IRAK-1 Inactivation Is Mediated by SHP-1 Interacting with an Evolutionarily Conserved KTIM Motif

Parasites of the Leishmania genus can rapidly alter several macrophage (MØ) signalling pathways in order to tame down the innate immune response and inflammation, therefore favouring their survival and propagation within their mammalian host. Having recently reported that Leishmania and bacterial LPS generate a significantly stronger inflammatory response in animals and phagocytes functionally deficient for the Src homology 2 domain-containing protein tyrosine phosphatase (SHP-1), we hypothesized that Leishmania could exploit SHP-1 to inactivate key kinases involved in Toll-like receptor (TLR) signalling and innate immunity such as IL-1 receptor-associated kinase 1 (IRAK-1). Here we show that upon infection, SHP-1 rapidly binds to IRAK-1, completely inactivating its intrinsic kinase activity and any further LPS-mediated activation as well as MØ functions. We also demonstrate that the SHP-1/IRAK-1 interaction occurs via an evolutionarily conserved ITIM-like motif found in the kinase domain of IRAK-1, which we named KTIM (Kinase Tyrosyl-based Inhibitory Motif). This regulatory motif appeared in early vertebrates and is not found in any other IRAK family member. Our study additionally reveals that several other kinases (e.g. Erk1/2, IKKα/β) involved in downstream TLR signalling also bear KTIMs in their kinase domains and interact with SHP-1. We thus provide the first demonstration that a pathogen can exploit a host protein tyrosine phosphatase, namely SHP-1, to directly inactivate IRAK-1 through a generally conserved KTIM motif

Gating of a pH-Sensitive K2P Potassium Channel by an Electrostatic Effect of Basic Sensor Residues on the Selectivity Filter

K+ channels share common selectivity characteristics but exhibit a wide diversity in how they are gated open. Leak K2P K+ channels TASK-2, TALK-1 and TALK-2 are gated open by extracellular alkalinization. The mechanism for this alkalinization-dependent gating has been proposed to be the neutralization of the side chain of a single arginine (lysine in TALK-2) residue near the pore of TASK-2, which occurs with the unusual pKa of 8.0. We now corroborate this hypothesis by transplanting the TASK-2 extracellular pH (pHo) sensor in the background of a pHo-insensitive TASK-3 channel, which leads to the restitution of pHo-gating. Using a concatenated channel approach, we also demonstrate that for TASK-2 to open, pHo sensors must be neutralized in each of the two subunits forming these dimeric channels with no apparent cross-talk between the sensors. These results are consistent with adaptive biasing force analysis of K+ permeation using a model selectivity filter in wild-type and mutated channels. The underlying free-energy profiles confirm that either a doubly or a singly charged pHo sensor is sufficient to abolish ion flow. Atomic detail of the associated mechanism reveals that, rather than a collapse of the pore, as proposed for other K2P channels gated at the selectivity filter, an increased height of the energetic barriers for ion translocation accounts for channel blockade at acid pHo. Our data, therefore, strongly suggest that a cycle of protonation/deprotonation of pHo-sensing arginine 224 side chain gates the TASK-2 channel by electrostatically tuning the conformational stability of its selectivity filter

Online assessment of ALS functional rating scale compares well to in-clinic evaluation: A prospective trial

Self-assessment of symptom progression in chronic diseases is of increasing importance in clinical research, patient management and specialized outpatient care. Against this background, we developed a secure internet platform (ALShome.de) that allows online assessment of the revised ALS Functional Rating Scale (ALSFRS-R) and other established self-assessment questionnaires. We developed a secure and closed internet portal to assess patient reported outcomes. In a prospective, controlled and stratified study, patients conducted a web-based self-assessment of ALSFRS-R compared to on-site assessment. On-site and online assessments were compared at baseline (n = 127) and after 3.5 months (n = 81, 64%). Results showed that correlation between on-site evaluation and online testing of ALSFRS-R was highly significant (r = 0.96; p < 0.001). The agreement of both capturing methods (online vs. on-site) was excellent (mean interval, 8.8 days). The adherence to online rating was high; 75% of patients tested on-site completed a follow-up online visit (mean 3.5 months, SD 1.7). We conclude that online self-assessment of ALS severity complements the well-established face-to-face application of the ALSFRS-R during on-site visits. The results of our study support the use of online administration of ALSFRS-R within clinical trials and for managing the care of ALS patients