The minimal gene set member msrA, encoding peptide methionine sulfoxide reductase, is a virulence determinant of the plant pathogen Erwinia chrysanthemi

Peptide methionine sulfoxide reductase (MsrA), which repairs oxidized proteins, is present in most living organisms, and the cognate structural gene belongs to the so-called minimum gene set [Mushegian, A. R. & Koonin, E. V., (1996) Proc. Natl. Acad. Sci. USA 93, 10268–10273]. In this work, we report that MsrA is required for full virulence of the plant pathogen Erwinia chrysanthemi. The following differences were observed between the wild-type and a MsrA⁻ mutant: (i) the MsrA⁻ mutant was more sensitive to oxidative stress; (ii) the MsrA⁻ mutant was less motile on solid surface; (iii) the MsrA⁻ mutant exhibited reduced virulence on chicory leaves; and (iv) no systemic invasion was observed when the MsrA⁻ mutant was inoculated into whole Saintpaulia ionantha plants. These results suggest that plants respond to virulent pathogens by producing active oxygen species, and that enzymes repairing oxidative damage allow virulent pathogens to survive the host environment, thereby supporting the theory that active oxygen species play a key role in plant defense.     

Pharmacological characterization of muscarinic receptors implicated in rabbit detrusor muscle contraction and activation of inositol phospholipid hydrolysis in rabbit detrusor and parotid gland

In the present study, we evaluated the pharmacological characteristics of the functional muscarinic receptors implicated in rabbit detrusor contraction and coupled to inositol phospholipid turnover in rabbit detrusor and parotid gland. The selectivity of several muscarinic antagonists for detrusor vs. salivary gland muscarinic receptors was also examined. The affinities for the muscarinic m1-, m2- and m3-receptor subtypes were determined using membranes from human cloned receptors expressed in CHO-K1 cells using [3H]-N-methyl scopolamine as a radioligand. Anti-muscarinic activity was determined in isolated rabbit detrusor by measuring the displacement of the contractile response to carbachol, and in rabbit detrusor and rabbit parotid by measuring the displacement of inositol phospholipid hydrolysis (total inositol phosphate accumulation) to carbachol. A significant correlation was found between the potencies to antagonize carbachol-induced rabbit detrusor contraction (pK(B)) and the affinities (pKi) for the m3-receptor subtype (r = 0.93, P = 5 x 10(-6)). Lower, but significant, correlations [0.88 (P = 6.3 x 10(-5)), 0.72 (P = 4.6 x 10(-3))] were obtained with m1- or m2-receptor subtypes, respectively. Each muscarinic antagonist tested displayed similar potency to antagonize carbachol-stimulated inositol phospholipid hydrolysis in rabbit detrusor and parotid (r = 0.96, P = 8 x 10(-3)). A significant correlation was found between the potencies to antagonize carbachol-stimulated inositol phospholipid hydrolysis (pK(B)), determined in rabbit detrusor and rabbit parotid, and the affinities (pK(i)) for the m3-receptor subtype [r = 0.96 (P = 0.01), 0.99 (P = 5 x 10(-5)), respectively] and for the m1-receptor subtype [r = 0.98 (P = 3.5 x 10(-3)), 0.94 (P = 0.02), respectively] but not for the m2-receptor subtype [r = 0.33, 0.57, ns, respectively]. In each in vitro assay, methoctramine (preferential M2 selective antagonist) and pirenzepine (preferential M1 selective antagonist) were slightly potent. We suggest that the muscarinic receptor implicated in the response to carbachol in rabbit detrusor and parotid gland corresponds to the M3-subtype. None of the muscarinic antagonists studied in rabbit tissues displayed preferential affinity for the detrusor.     

Standards for Detecting,Interpreting, and Reporting Noncontrast Computed Tomographic Markers of Intracerebral Hemorrhage Expansion

Significant hematoma expansion (HE) affects one‐fifth of people within 24 hours after acute intracerebral hemorrhage (ICH), and its prevention is an appealing treatment target. Although the computed tomography (CT)‐angiography spot sign predicts HE, only a minority of ICH patients receive contrast injection. Conversely, noncontrast CT (NCCT) is used to diagnose nearly all ICH, so NCCT markers represent a widely available alternative for prediction of HE. However, different NCCT signs describe similar features, with lack of consensus on the optimal image acquisition protocol, assessment, terminology, and diagnostic criteria. In this review, we propose practical guidelines for detecting, interpreting, and reporting NCCT predictors of HE. ANN NEUROL 2019;86:480–492     

The contribution of haemoglobin mass to increases in cycling performance induced by simulated LHTL

We sought to determine whether improved cycling performance following ‘Live High-Train Low’ (LHTL) occurs if increases in haemoglobin mass (Hb_mass) are prevented via periodic phlebotomy during hypoxic exposure. Eleven, highly trained, female cyclists completed 26 nights of simulated LHTL (16 h day⁻¹, 3000 m). Hb_mass was determined in quadruplicate before LHTL and in duplicate weekly thereafter. After 14 nights, cyclists were pair-matched, based on their Hb_mass response (ΔHb_mass) from baseline, to form a response group (Response, n = 5) in which Hb_mass was free to adapt, and a Clamp group (Clamp, n = 6) in which ΔHb_mass was negated via weekly phlebotomy. All cyclists were blinded to the blood volume removed. Cycling performance was assessed in duplicate before and after LHTL using a maximal 4-min effort (MMP_4min) followed by a ride time to exhaustion test at peak power output (T _lim). VO_2peak was established during the MMP_4min. Following LHTL, Hb_mass increased in Response (mean ± SD, 5.5 ± 2.9%). Due to repeated phlebotomy, there was no ΔHb_mass in Clamp (−0.4 ± 0.6%). VO_2peak increased in Response (3.5 ± 2.3%) but not in Clamp (0.3 ± 2.6%). MMP_4min improved in both the groups (Response 4.5 ± 1.1%, Clamp 3.6 ± 1.4%) and was not different between groups (p = 0.58). T _lim increased only in Response, with Clamp substantially worse than Response (−37.6%; 90% CL −58.9 to −5.0, p = 0.07). Our novel findings, showing an ~4% increase in MMP_4min despite blocking an ~5% increase in Hb_mass, suggest that accelerated erythropoiesis is not the sole mechanism by which LHTL improves performance. However, increases in Hb_mass appear to influence the aerobic contribution to high-intensity exercise which may be important for subsequent high-intensity efforts.     

Fragment N2, a caspase‐3‐generated RasGAP fragment,inhibits breast cancer metastatic progression

The p120 RasGAP protein negatively regulates Ras via its GAP domain. RasGAP carries several other domains that modulate several signaling molecules such as Rho. RasGAP is also a caspase‐3 substrate. One of the caspase‐3‐generated RasGAP fragments, corresponding to amino acids 158–455 and called fragment N2, was previously reported to specifically sensitize cancer cells to death induced by various anticancer agents. Here, we show that fragment N2 inhibits migration in vitro and that it impairs metastatic progression of breast cancer to the lung. Hence, stress‐activated caspase‐3 might contribute to the suppression of metastasis through the generation of fragment N2. These results indicate that the activity borne by fragment N2 has a potential therapeutic relevance to counteract the metastatic process.