ライフサイエンスコーパス: outer membrane

1 former anchored to the inner leaflet of the outer membrane.

2 the TOM complex, the main translocase in the outer membrane.

3 es proBFT following its transport across the outer membrane.

4 ets bacteria by rapidly permeabilizing their outer membrane.

5 known that these lipids are not made in the outer membrane.

6 calisation of these phospholipids within the outer membrane.

7 teins and insert them into the mitochondrial outer membrane.

8 d mislocalized proteins at the mitochondrial outer membrane.

9 gy-dependent pyocin translocation across the outer membrane.

10 AK and BAX to permeabilize the mitochondrial outer membrane.

11 tein-conducting channel in the mitochondrial outer membrane.

12 factors, toxins and enzymes across the cell outer membrane.

13 erpendicularly and the needle penetrates the outer membrane.

14 hibit protein synthesis on the mitochondrial outer membrane.

15 g a relic of a former flagellar motor in the outer membrane.

16 hannel (VDAC) oligomers in the mitochondrial outer membrane.

17 LPS) exclusively found on the surface of the outer membrane.

18 erved lipid A component of the Gram-negative outer membrane.

19 in directions parallel and orthogonal to the outer membrane.

20 charides in the extracellular leaflet of the outer membrane.

21 -anchored ER proteins from the mitochondrial outer membrane.

22 but it is associated with the mitochondrial outer membrane.

23 the inner membrane and transport them to the outer membrane.

24 rocess by forming pores in the mitochondrial outer membrane.

25 f precursors blocking the import pore in the outer membrane.

26 ligomer that permeabilizes the mitochondrial outer membrane.

27 cted link between FtsEX and integrity of the outer membrane.

28 sporting phospholipids between the inner and outer membranes.

29 m E. coli, in their native, species-specific outer membranes.

30 nterograde lipid transport from the inner to outer membranes.

31 transport across the Gram-negative inner and outer membranes.

32 nt amounts of HgbA in whole-cell lysates and outer membranes.

33 harides are critical components of bacterial outer membranes.

34 ines fold and insert these proteins into the outer membrane(3-5).

35 ol the permeabilization of the mitochondrial outer membrane, a crucial step in the modulation of apop

36 B, and blocking the function of the Shigella outer membrane actin motility factor IcsA.

37 C16 fatty acid (palmitate) to lipid A by the outer membrane acyltransferase enzyme PagP occurs in imm

38 le we observed increased permeability of the outer membrane after exoskeleton deposition, this had a

39 the decorated P and L rings persists in the outer membrane after flagellum disassembly.

40 function of the P and L rings is to seal the outer membrane after motor disassembly.

41 nthases and hydrolases require activation by outer-membrane-anchored lipoproteins.

42 low porin-mediated passive uptake across the outer membrane and active efflux via efflux pumps in the

43 e most abundant protein in the mitochondrial outer membrane and an archetypical beta-barrel channel.

44 ir complex cell envelope, which comprises an outer membrane and an inner membrane, are an important a

45 iciously chosen surfactant permeabilized the outer membrane and enhanced this effect.

46 hat are located at the interface between the outer membrane and external medium, on the sorption and

47 t in the permeability barrier imposed by the outer membrane and offers a pathogen-associated molecula

48 s driven by phospholipid accumulation in the outer membrane and regulated by the phospholipid transpo

49 structure and function of Ail in a bacterial outer membrane and set the stage for probing its interac

50 tem is required for translocation across the outer membrane and that a cysteine-rich region directs T

51 ergies of the inner membrane, cell wall, and outer membrane and that the experimentally observed time

52 cs stress response when damage occurs in the outer membrane and the peptidoglycan.

53 protein TraH(N) was found to localize to the outer membrane and the presence of significant amounts o

54 ed the low permeability of the mycobacterial outer membrane, and the PE/PPE proteins apparently act a

55 elationship between antibody, O-Ag and other outer-membrane antigens is poorly understood.

56 The distinctive properties of the outer membrane are due to the presence of lipopolysaccha

57 barrel outer membrane proteins (OMPs) to the outer membrane are mediated by the beta-barrel assembly

58 s the inner membrane at weakly acidic pH and outer membrane at highly acidic pH are found to play key

59 he cell envelope is critical to maintain the outer membrane barrier, which plays a key role in virule

60 ns across inner membrane and the assembly of outer membrane beta-barrel precursors were severely comp

61 ng expression of essential genes involved in outer membrane biogenesis can also trigger T6SS activati

62 her bacteria, lipoproteins can contribute to outer membrane biogenesis through direct binding of subs

63 that have been identified to participate in outer-membrane biogenesis: LPS transport via the Lpt mac

64 mblies of VDAC are observed in mitochondrial outer membranes, but they do not predominate in detergen

65 anism to export large CdiA toxins across the outer membrane by dedicated outer membrane transporters

66 ive bacteria, DNA is first pulled toward the outer membrane by retraction of the pilus and then taken

67 , a surface-exposed central passenger and an outer membrane C-terminal translocator, self-recognise i

68 between distinct structural features of the outer membrane cap (OMC) and periplasmic ring (PR).

69 containing five proteins, organized into an outer membrane cap (OMC), a periplasmic ring (PR) and a

70 ng translocation to the cell surface via the outer membrane channel FhaC.

71 Symmetry mismatch between the outer membrane complex and assembly platform is overcome

72 teracts on the surface of live cells with an outer membrane component of the efflux pump, TolC, stimu

73 s include multi-gene phase variation (PV) of outer membrane components, multi-allele PV of restrictio

74 istance, cell division, and translocation of outer membrane components.

75 Gram-negative bacteria are surrounded by an outer membrane composed of phospholipids and lipopolysac

76 We conclude that outer membrane constriction is coordinated with cell div

77 Coordination of outer membrane constriction with septation is critical t

78 The inner leaflet of the outer membrane contains phospholipids, whereas the fatty

79 The outer membrane contains proteins with a beta-barrel stru

80 as three sub-assemblies: a 14-fold symmetric outer membrane core complex (OMCC), 17-fold symmetric pe

81 proteins with homology to the conserved T4SS outer membrane core proteins and F-type-specific protein

82 We show that BtuB, the outer membrane corrinoid transporter, mediates the uptak

83 -2 proteins oligomerize at the mitochondrial outer membrane during MOMP, inducing pore formation.

84 how that motor disassembly results in stable outer membrane-embedded sub-complexes.

85 The Gram-negative outer-membrane envelops the bacterium and functions as a

86 lysis is consistent with both the inner and outer membranes exceeding characteristic estimates of th

87 likely functions as a juncture domain at the outer membrane-extracellular medium interface.

88 h LL-37 show membrane discontinuities in the outer membrane followed by cell wall damage and cell dea

89 beta-Barrel Assembly Machinery (BAM) in the outer-membrane for insertion and folding.

90 acteria, lipopolysaccharide is essential for outer membrane formation and antibiotic resistance.

91 elic, likely to prevent leakage across their outer membrane; furthermore, we show that ejection is tr

92 n-related GTPases that mediate mitochondrial outer-membrane fusion, a process that is required for mi

93 Here, we identify RagAB as the outer-membrane importer for these peptides.

94 meter-sized clusters along the mitochondrial outer membrane in association with the Mitochondrial Con

95 ctors serve to maintain the integrity of the outer membrane, including DolP (formerly YraP) a protein

96 n implicated in phospholipid trafficking and outer membrane integrity, and includes an ABC transporte

97 ng across the bacterial envelope to maintain outer membrane integrity.

98 longate successfully, and display no loss of outer membrane integrity.

99 cherichia coli by reducing levels of LPS and outer membrane integrity.

100 icient for unclasping the inner-membrane and outer-membrane interactions of integrin dimer, thus ruli

101 extends the extracellular channel across the outer membrane into the periplasm.

102 Permeabilization of the mitochondrial outer membrane is a key step in the intrinsic apoptosis

103 The outer membrane is a key virulence determinant of gram-ne

104 Low permeability across the outer membrane is a major reason why most antibiotics ar

105 saccharide movement across the bridge to the outer membrane is unknown(2).

106 ly compromise the integrity of the bacterial outer-membrane, it also deactivates efflux pump systems

107 able tension asymmetry between the inner and outer membrane leaflets.

108 The Mla pathway maintains outer membrane lipid asymmetry by transporting phospholi

109 ycocerosate (PDIM), one of the most abundant outer membrane lipids, plays important roles in both def

110 in the synthesis and export of mycobacterial outer membrane lipids.

111 saccharide represents the variable region of outer membrane lipopolysaccharides.

112 ed a high-resolution structure of the LT, an outer membrane lipoprotein from Neisseria species with a

113 The stalling of an abundant outer membrane lipoprotein, Lpp, at the periplasmic face

114 the recruitment of the peptidoglycan-binding outer-membrane lipoprotein Pal at division sites by the

115 d on the cytosolic side of the mitochondrial outer membrane (MOM) but does not cross it.

116 ure-sensitive (ts-) peripheral mitochondrial outer membrane (MOM) proteins as novel model QC substrat

117 we examine recent findings on mitochondrial outer membrane (MOM)-associated mRNA translation, how th

118 lete recruitment of BAX to the mitochondrial outer membrane (MOM).

119 of metergoline reveals hypersensitization of outer membrane mutants to metergoline activity.

120 lkL is known to increase permeability of the outer membrane of bacteria for hydrophobic molecules, ye

121 range of barrel-shaped proteins found in the outer membrane of certain bacteria evolved through multi

122 In the outer membrane of Enterobacteriaceae, trimeric porins co

123 OMP that inserts lipopolysaccharide into the outer membrane of Escherichia coli.

124 Lipopolysaccharides are anchored to the outer membrane of Gram-negative bacteria by a hydrophobi

125 igate the fosfomycin permeability across the outer membrane of Gram-negative bacteria by electrophysi

126 The highly asymmetric outer membrane of Gram-negative bacteria functions in th

127 e surface charge of the outer leaflet of the outer membrane of Gram-negative bacteria is already neut

128 The outer membrane of Gram-negative bacteria is essential fo

129 The outer membrane of Gram-negative bacteria is of great sci

130 e permeation of most antibiotics through the outer membrane of Gram-negative bacteria occurs through

131 Lipopolysaccharide (LPS) resides in the outer membrane of Gram-negative bacteria where it is res

132 Lipopolysaccharide (LPS), a component of the outer membrane of gram-negative bacteria, disrupts the a

133 OmpA, a protein commonly found in the outer membrane of Gram-negative bacteria, has served as

134 ere, we show that the major component of the outer membrane of gram-negative bacteria, lipopolysaccha

135 In the outer membrane of Gram-negative bacteria, membrane prote

136 In the outer membrane of gram-negative bacteria, O-antigen segm

137 ha-helical porin that spans the mycolic acid outer membrane of Gram-positive mycolate, Corynebacteriu

138 Lipid A family of glycolipids, found in the outer membranes of all Gram-negative bacteria, exhibits

139 teractions between proteins in the inner and outer membranes of the Gram-negative envelope may provid

140 The outer-membrane of Gram-negative bacteria is critical for

141 ork identifies RagAB as a dynamic, selective outer-membrane oligopeptide-acquisition machine that is

142 SPI-1) type III secretion system (T3SS)) and outer membrane (OM) (15-mer InvG, a member of the broadl

143 eudomonas aeruginosa by interacting with the outer membrane (OM) and inducing its curvature.

144 rates into the cell, mediated by specialised outer membrane (OM) channels.

145 e, we demonstrate that various treatments to outer membrane (OM) constituents do not affect the buffe

146 The outer membrane (OM) is a defining feature of Gram-negati

147 s widely conserved machinery compromises the outer membrane (OM) layer of these organisms, resulting

148 cally anticipated that other members with an outer membrane (OM) might exist in this phylum.

149 Trimeric porins in the outer membrane (OM) of Gram-negative bacteria are the co

150 The outer membrane (OM) of gram-negative bacteria confers in

151 The outer membrane (OM) of Gram-negative bacteria exhibits u

152 The asymmetric outer membrane (OM) of Gram-negative bacteria functions

153 The outer membrane (OM) of Gram-negative bacteria is a selec

154 The outer membrane (OM) of Gram-negative bacteria is an asym

155 ent the major proteinaceous component of the outer membrane (OM) of Gram-negative bacteria.

156 homotypic binding, and in so doing exchanges outer membrane (OM) proteins and lipids between cells wi

157 The extracellular loops of bacterial outer membrane (OM) transporters are thought to sample a

158 teria have a cell envelope that comprises an outer membrane (OM), a peptidoglycan (PG) layer and an i

159 t spatial locations, inner membrane (IM) and outer membrane (OM), thus forming a robust permeability

160 directing lipoproteins from the inner to the outer membrane (OM), with many of these lipoproteins coo

161 Outer membrane (OM)-associated glycolipids of gut commen

162 es is driven by lipoproteins anchored in the outer membrane (OM).

163 F1 complex with the F pilus attached at the outer membrane (OM).

164 beling is performed with E. coli or isolated outer membranes (OMs) under selective conditions.

165 tibiotics are either unable to penetrate the outer-membrane or are excluded by efflux mechanisms.

166 ic cell death involved loss of mitochondrial outer membrane permeability and activation of caspases 3

167 ype K. pneumoniae, and coadministration with outer membrane permeability enhancers profoundly sensiti

168 The synergistic action of outer membrane permeability, efflux pump activities and

169 n intoxicated cells, together with increased outer membrane permeability.

170 ical role in their virulence by changing the outer membrane permeability.

171 aluated by using fluorescent dyes to measure outer-membrane permeability and to determine membrane de

172 r light-mediated initiation of mitochondrial outer membrane permeabilization (MOMP) and downstream ap

173 Mitochondrial outer membrane permeabilization (MOMP) is a core event i

174 Mitochondrial outer membrane permeabilization (MOMP) is a crucial even

175 on of mitochondrial apoptosis, mitochondrial outer membrane permeabilization (MOMP) usually commits a

176 BCL-2) protein family regulate mitochondrial outer membrane permeabilization (MOMP), a phenomenon in

177 sis induces cell death through mitochondrial outer membrane permeabilization (MOMP), which is conside

178 ol a decisive apoptotic event: mitochondrial outer membrane permeabilization (MOMP).

179 mitochondrial DNA depletion or mitochondrial outer membrane permeabilization blockage via BCL2 overex

180 ive, our findings suggest that mitochondrial outer membrane permeabilization may represent a valid ta

181 ly known as key controllers of mitochondrial outer membrane permeabilization, arguably the most impor

182 as one of the factors causing mitochondrial outer-membrane permeabilization (MOMP).

183 hanisms: (i) beta-lactamase inhibitors; (ii) outer membrane permeabilizers; (iii) efflux pump inhibit

184 me potency assessments in the presence of an outer membrane-permeabilizing agent or in efflux-comprom

185 We conclude that outer membrane perturbation can be sensed by P. aerugino

186 hemical perturbation or by a mutation in the outer-membrane pilus secretin CpaC stimulates early init

187 ve as CD27-sufficient cells to mitochondrial outer membrane polarization upon exposure to either BH3

188 itochondria, and chloroplasts all possess an outer membrane populated with a host of beta-barrel oute

189 cerevisiae IgA or IgG, anti-Escherichiacoli outer membrane porin C, anti-CBir1, anti-flagellin 2, an

190 ed lipopolysaccharide (LPS) and depletion of outer membrane porin OmpT, which confers resistance to h

191 Of note, an outer-membrane porin (omp)-deficient strain of Escherich

192 e bacteria only by passive diffusion through outer membrane porins.

193 aride (LPS) from the Gram-negative bacterial outer membrane potently activates the human innate immun

194 and is linked to its function of regulating outer membrane properties.

195 iously optimized as a substrate for OmpT, an outer-membrane protease on E. coli.

196 lular and humoral immunity against the major outer membrane protein (MOMP) of Chlamydia trachomatis.

197 Its porA gene encodes the major outer membrane protein (MOMP) that is abundantly express

198 riplasmic chaperone SurA plays a key role in outer membrane protein (OMP) biogenesis.

199 bility of a C. trachomatis recombinant major outer membrane protein (rMOMP) vaccine to elicit cross-s

200 phagocytophilum surface protein (Asp14), and outer membrane protein A (OmpA) are essential for optima

201 oscopy to confirm the spontaneous folding of outer membrane protein A (OmpA) into preformed NDs.

202 is (Arabidopsis thaliana), the mitochondrial outer membrane protein DGD1 SUPPRESSOR1 (DGS1) is part o

203 stable ectopic expression of a mitochondrial outer membrane protein fused to a GFP:Strep tag in Arabi

204 Here, we constructed an outer membrane protein G (OmpG) nanopore with a caspase

205 (AML) cells, we identified the mitochondrial outer membrane protein mitochondrial carrier homolog 2 (

206 Ail, a multifunctional outer membrane protein of Yersinia pestis, confers cell

207 We show that OmpU, a major outer membrane protein positively regulated by ToxR, has

208 r membrane via porins after first binding an outer membrane protein receptor.

209 Mitofusin2 (Mfn2) is a mitochondrial outer membrane protein regulating mitochondrial fusion,

210 IcsA is an outer membrane protein secreted at the bacterial pole th

211 stest, whereas inactivating cell division or outer membrane protein synthesis blocked it the slowest.

212 on E. coli, suggesting that HasF is a major outer membrane protein that is used by all RND efflux sy

213 ccine strain (LVS) identified a role for the outer membrane protein TolC in modulation of host cell r

214 phage LL5, as were mutants deficient in the outer membrane protein TolC.

215 cal sensory rhodopsin II and the beta-barrel outer membrane protein W have been investigated in lipid

216 Elevated repeat numbers in outer-membrane protein genes of the 2013 strain are indi

217 Mitofusin-2 (MFN2) is a mitochondrial outer-membrane protein that plays a pivotal role in mito

218 network ensures the biogenesis of bacterial outer membrane proteins (OMPs) and has recently been ide

219 Bacterial outer membrane proteins (OMPs) contain a unique "beta ba

220 Integral beta-barrel outer membrane proteins (OMPs) function to establish and

221 es to search for homologs of known bacterial outer membrane proteins (OMPs) led to the identification

222 beta-Barrel outer membrane proteins (OMPs) represent the major prote

223 ia, the folding and insertion of beta-barrel outer membrane proteins (OMPs) to the outer membrane are

224 dominant membrane proteins, i.e., two 28-kDa outer membrane proteins (P28/OMP) and a 120-kDa surface

225 eponema phylogroups for putative beta-barrel outer membrane proteins and considered their potential a

226 bacterial pathogen Vibrio cholerae jettisons outer membrane proteins and lipids in vesicles as it ent

227 a subunit vaccine containing two recombinant outer membrane proteins as recombinant antigens (RCA) an

228 st that chemotaxis, regulatory functions and outer membrane proteins contribute to specific adaptatio

229 In mitochondria, beta-barrel outer membrane proteins mediate protein import, metaboli

230 embrane populated with a host of beta-barrel outer-membrane proteins (betaOMPs).

231 major constituent - hydrophobic beta-barrel Outer-Membrane Proteins (OMPs) - are first secreted acro

232 vaccine development based on surface-exposed outer-membrane proteins and the design of novel antichol

233 Multiple outer-membrane proteins of meningococci are subject to p

234 We show BBA57 translocation to the outer membrane, purification at a level sufficient for s

235 The Escherichia coli outer membrane receptor FepA transports ferric enterobac

236 rom the extracellular hemophore HasAp to the outer membrane receptor HasR is required for activation

237 ptual framework for how microbes use a fluid outer membrane receptor to recognize and assemble kin ce

238 Some bacteria also express outer membrane receptors for iron-binding proteins of th

239 cular mechanism by which YejM is involved in outer membrane remodeling will help to identify a new dr

240 nce of significant amounts of TraH(N) in the outer membrane requires TraG(N) .

241 ur data show that Bax clusters localize near outer membrane ruptures of highly variable size.

242 envelope and extrudes substrates through an outer membrane secretin channel using a pseudopilus.

243 nd retracting to thread this DNA through the outer membrane secretin, PilQ.

244 and osmotic protection to the cell, and the outer membrane serves as a permeability barrier against

245 st of bacterial small molecule siderophores, outer membrane siderophore receptors, the TonB-ExbBD ene

246 Here, we report the atomic structure of an outer membrane spanning protein complex, MtrAB, that is

247 harbour genes encoding a thrombospondin-like outer membrane structure that probably serves as a barri

248 We found several genes involved in outer membrane structure were differentially expressed b

249 lecules that interact with the P. aeruginosa outer membrane such as polymyxin B can also trigger asse

250 Mycobacterium tuberculosis has an unusual outer membrane that lacks canonical porin proteins for t

251 Gram-negative pathogens are enveloped by an outer membrane that serves as a double-edged sword: On t

252 Together with the employment of an outer membrane, the detection range of the sensor with b

253 obacteria have a distinctive glycolipid-rich outer membrane, the mycomembrane, which is a critical ta

254 ther a porin or the hydrophobic layer of the outer membrane, then traverse the hydrophilic peptidogly

255 ative bacteria with proteins tethered to the outer membrane through a lipid anchor.

256 ll as the transport of lipid moieties to the outer membrane to establish membrane rigidity and stabil

257 actant that destabilizes the rigidity of the outer membrane to exert pleiotropic effects on the funct

258 -induced lipopolysaccharide release from the outer membrane to further maintain cell integrity.

259 acting protein rings, spanning the inner and outer membranes to form the ~45-50-nm protein complex, h

260 rsor proteins through the translocase of the outer membrane (TOM) complex.

261 protein TonB to dislodge the plug domains of outer membrane TonB-dependent nutrient transporters.

262 terminal signaling domain (NTSD) of PupB, an outer-membrane TonB-dependent transducer.

263 gnizes bacterial cells by binding to Hur, an outer-membrane TonB-dependent transporter.

264 an inhibit pro-apoptotic BCL-2 mitochondrial outer membrane translocation and oligomerization.

265 inner membrane, they failed to identify any outer-membrane translocon homologs, which raised the que

266 time and bypass the requirement for the TonB outer membrane transporter to allow expression of xoxF1

267 oxins across the outer membrane by dedicated outer membrane transporters called CdiB.

268 generation of major surface protein 2 (Msp2) outer membrane variants to establish persistent infectio

269 tibiotic susceptibility, osmotic stress, and outer membrane vesicle (OMV) production, suggesting that

270 nt membrane distortion and the production of outer membrane vesicle-like features, while NPs bearing

271 santandreae largely provisions its host via outer-membrane vesicle secretion.

272 Outer membrane vesicles (OMVs) are spherical liposomes t

273 Outer membrane vesicles (OMVs) produced by Gram-negative

274 The outer membrane vesicles (OMVs) produced by P. gingivalis

275 Bacterial outer membrane vesicles (OMVs) represent an interesting

276 Bacteria have been described to release outer membrane vesicles (OMVs) that are capable of media

277 We further defined that the outer membrane vesicles (OMVs) that were derived from th

278 displayed increased biogenesis of bacterial outer membrane vesicles (OMVs).

279 is dynamically and selectively packaged into outer membrane vesicles (OMVs).

280 ntistimulatory versus prostimulatory CPSs on outer membrane vesicles also regulated immune responses.

281 Msp in intact organisms or outer membrane vesicles also restricts PIP signaling.

282 Gram-negative bacteria release outer membrane vesicles into the external milieu to deli

283 Outer membrane vesicles produced by Gram-negative bacter

284 cies, including enveloped viruses, bacterial outer membrane vesicles, and mammalian extracellular ves

285 Importantly, intact T. forsythia cells or outer membrane vesicles, both of which carry surface-ass

286 The symbionts load SsrA into outer membrane vesicles, which are transported specifica

287 Gram-negative bacteria produce outer-membrane vesicles (OMVs) that package genetic elem

288 Thus, bacteria use outer membrane vesiculation to exchange cell surface com

289 the localization of an adhesin, LapA, to the outer membrane via a variant of the classical type I sec

290 it has been hypothesized that HPS exits the outer membrane via an atypical T4P-driven mechanism.

291 n maintaining the asymmetrical Gram-negative outer membrane via retrograde phospholipid transport.

292 cruitment of IRAK2 Myddosome to mitochondria outer membranes via recognition by TOM20, followed by TI

293 In the present work, the Escherichia coli outer membrane vitamin B(12) transporter, BtuB, was spin

294 nergistic, suggesting that the Gram-negative outer membrane was a significant barrier for alkynyl-bis

295 that mimic the composition of mitochondrial outer membranes, we show that functionally important bin

296 One such strategy is to remodel the outer membrane where several genes are involved.

297 the stringent permeability properties of the outer membrane, which is particularly resistant to perme

298 d by an inner cytoplasmic membrane and by an outer membrane, which serves as a protective barrier to

299 m37 are located on the cytosolic side of the outer membrane, with Sam35 capping Sam50, and Sam37 inte

300 erial cell envelopes, encompassing inner and outer membranes, yield high-resolution solid-state NMR s