Effects Of M3 Research Articles

The efficacy of a TrkB monoclonal antibody agonist in preserving the auditory nerve in deafened guinea pigs

The auditory nerve typically degenerates following loss of cochlear hair cells or synapses. In the case of hair cell loss neural degeneration hinders restoration of hearing through a cochlear implant, and in the case of synaptopathy suprathreshold hearing is affected, potentially degrading speech perception in noise. It has been established that neurotrophins such as brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) can mitigate auditory nerve degeneration. Several potential BDNF mimetics have also been investigated for neurotrophic effects in the cochlea. A recent in vitro study showed favorable effects of M3, a TrkB monoclonal antibody agonist, when compared with BDNF. In the present study we set out to examine the effect of M3 on auditory nerve preservation in vivo. Thirty-one guinea pigs were bilaterally deafened, and unilaterally treated with a single 3-µl dose of 7 mg/ml, 0.7 mg/ml M3 or vehicle-only by means of a small gelatin sponge two weeks later. During the experiment and analyses the experimenters were blinded to the three treatment groups. Four weeks after treatment, we assessed the treatment effect (1) histologically, by quantifying survival of SGCs and their peripheral processes (PPs); and (2) electrophysiologically, with two different paradigms of electrically evoked compound action potential (eCAP) recordings shown to be indicative of neural health: single-pulse stimulation with varying inter-phase gap (IPG), and pulse-train stimulation with varying inter-pulse interval. We observed a consistent and significant preservative effect of M3 on SGC survival in the lower basal turn (approximately 40% more survival than in the untreated contralateral cochlea), but also in the upper middle and lower apical turn of the cochlea. This effect was similar for the two treatment groups. Survival of PPs showed a trend similar to that of the SGCs, but was only significantly higher for the highest dose of M3. The protective effect of M3 on SGCs was not reflected in any of the eCAP measures: no statistically significant differences were observed between groups in IPG effect nor between the M3 treatment groups and the control group using the pulse-train stimulation paradigm. In short, while a clear effect of M3 was observed on SGC survival, this was not clearly translated into functional preservation.

Antagonism of m3 Alleviates Type 2 Inflammation in Allergic Rhinitis Mice.

Type 2 immune cells play a pivotal role in allergic rhinitis (AR). Increasing evidence shows that inhibition of cholinergic nerve activity decreases the severity of airway diseases including asthma and AR. However, the role of the cholinergic receptor muscarinic 3 (m3) in type 2 inflammation in AR is unknown. We aimed to investigate the effect of m3 on the type 2 immune response, including both T helper 2 (Th2)-mediated and type 2 innate lymphocyte (ILC2)-mediated inflammation, in AR. Peripheral blood mononuclear cells (PBMCs) from human were cultured in vitro. Treatment with the m3 antagonist 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (4-DAMP) was used. The percentages of Th2 and ILC2 cells in PBMCs were evaluated by flow cytometry. AR mouse models were established by house dust mite (HDM) sensitization, and treated with tiotropium intranasally. The expression of Th2 cytokines, ILC2 cytokines and related factors in the nasal mucosa was assessed by immunohistochemistry and quantitative real-time polymerase chain reaction. Serum HDM-specific immunoglobulin E (sIgE) level was detected by enzyme-linked immunosorbent assay. Both Th2 and ILC2 percentages in PBMCs were decreased after 4-DAMP treatment. Similarly, the levels of Th2 cytokines (interleukin 4 [IL-4] and IL-13) and ILC2 cytokines and related factors (IL-25, IL-33, GATA3 and RORα) were significantly decreased in the nasal mucosa of AR mice after tiotropium treatment. Furthermore, tiotropium treatment decreased the nasal symptom score, the serum sIgE level and eosinophil infiltration in AR mice. In addition, tiotropium decreased phospholipase Cγ1 (PLCγ1), PLCγ2, nuclear factor of activated T cell 1 (NFATc1), and NFATc2 mRNA levels in AR mice. Antagonism of m3 alleviated type 2 inflammation in the nasal mucosa of AR mice.

Polydopamine-Assisted Two-Dimensional Molybdenum Disulfide (MoS2)-Modified PES Tight Ultrafiltration Mixed-Matrix Membranes: Enhanced Dye Separation Performance.

Tight ultrafiltration (TUF) membranes with high performance have attracted more and more attention in the separation of organic molecules. To improve membrane performance, some methods such as interface polymerization have been applied. However, these approaches have complex operation procedures. In this study, a polydopamine (PDA) modified MoS2 (MoS2@PDA) blending polyethersulfone (PES) membrane with smaller pore size and excellent selectivity was fabricated by a simple phase inversion method. The molecular weight cut-off (MWCO) of as-prepared MoS2@PDA mixed matrix membranes (MMMs) changes, and the effective separation of dye molecules in MoS2@PDA MMMs with different concentrations were obtained. The addition amount of MoS2@PDA increased from 0 to 4.5 wt %, resulting in a series of membranes with the MWCO values of 7402.29, 7007.89, 5803.58, 5589.50, 6632.77, and 6664.55 Da. The MWCO of the membrane M3 (3.0 wt %) was the lowest, the pore size was defined as 2.62 nm, and the pure water flux was 42.0 L m−2 h−1 bar−1. The rejection of Chromotrope 2B (C2B), Reactive Blue 4 (RB4), and Janus Green B (JGB) in aqueous solution with different concentrations of dyes was better than that of unmodified membrane. The separation effect of M3 and M0 on JGB at different pH values was also investigated. The rejection rate of M3 to JGB was higher than M0 at different pH ranges from 3 to 11. The rejection of M3 was 98.17–99.88%. When pH was 11, the rejection of membranes decreased with the extension of separation time. Specifically, at 180 min, the rejection of M0 and M3 dropped to 77.59% and 88.61%, respectively. In addition, the membrane had a very low retention of salt ions, Nacl 1.58%, Na2SO4 10.52%, MgSO4 4.64%, and MgCl2 1.55%, reflecting the potential for separating salts and dyes of MoS2@PDA/PES MMMs.

Synthesis and Characterization of Zn/Al, Zn/Fe, and Zn/Cr Layered Double Hydroxides: Effect of M3+ ions Toward Layer Formation

Layered double hydroxides are composed by substitution of metal cation divalent and trivalent. Metal cation divalent and trivalent can be changed. In this work, effect metal cation trivalent (M3+) toward layer formation were studied. Synthesis of LDHs has used co-precipitation methods with molar ratio 3:1 and kept pH at 10. The result of synthesis was characterized by X-ray Diffraction (XRD) and Fourier Transform Infrared (FT-IR) analyses.

M3, a natural lignan xyloside, exhibits potent anticancer activity in HCT116 cells.

4-O-(2′,3′,4′-tri-O-methyl-β-D-xylopyranosyl) diphyllin (M3) is a cytotoxic compound that was first isolated from the aerial parts of Phyllanthus taxodiifolius. The current study demonstrated that M3, a lignan xyloside, exhibits anticancer effects in a number of cancer cell lines by MTT test, including HCT116 cells. An association was identified between M3 treatment and the reduced proliferation of cancer cells; the half maximal inhibitory concentration (IC50) value of M3 ranged from 0.08 to 1.12 µM. Furthermore, M3 was revealed to exhibit a stronger antiproliferative effect by Annexin-V-FLUOS test compared with VP-16, another natural lignan used in cancer treatment. Notably, the IC50 value of M3 with MTT test in HCT116 cells was 0.08 µM. In addition, it was revealed that M3 could induce apoptosis in HCT116 cells in a caspase-3-dependent manner at a lower concentration compared with VP-16. Further analysis identified that the antiproliferation effect of M3 was associated with the promotion of microtubule depolymerization by CytoDYNAMIX Screen 03 Tubulin Polymerization assay. In summary, the current study demonstrated that M3 could inhibit proliferation and induce apoptosis in HCT116 cells, which supports a potential therapeutic application of M3 in cancer treatment, particularly in colon cancer.

Metal-organic framework as luminescence turn-on sensor for selective detection of metal ions: Absorbance caused enhancement mechanism

The luminescence turn-on sensors are more suitable for the practical applications, because they can effectively avoid the wrong response and have a higher signal-to-noise in dark background, compared to the luminescent quenching probes. In this work, we use IRMOF-3 as a luminescent probe to systematically investigate its sensing behavior for detecting metal ions. By examining the relationship of absorbance and luminescent intensity of IRMOF-3 before and after adding metal ions, we propose a novel luminescence turn-on mechanism, i.e., absorbance caused enhancement (ACE) mechanism, to reveal the luminescence turn-on phenomena of IRMOF-3 for selectively sensing M3+ (Cr3+, Al3+, Ga3+, In3+) metal ions. By exploring the effects of M3+ ion concentrations on absorbance and luminescent intensity, we further confirm the ACE mechanism responsible for luminescence turn-on phenomena. The subsequent experimental results indicate that IRMOF-3 exhibits not only high sensitivity and anti-interference ability against M2+ and M+ metal ions, but also have excellent reusability and stability. In short, the ACE mechanism provides a possible strategy for designing luminescence turn-on probes.

Chemokine binding protein 'M3' limits atherosclerosis in apolipoprotein E-/- mice.

Chemokines are important in macrophage recruitment and the progression of atherosclerosis. The ‘M3’ chemokine binding protein inactivates key chemokines involved in atherosclerosis (e.g. CCL2, CCL5 and CX3CL1). We aimed to determine the effect of M3 on plaque development and composition. In vitro chemotaxis studies confirmed that M3 protein inhibited the activity of chemokines CCL2, CCL5 and CX3CL1 as primary human monocyte migration as well as CCR2-, CCR5- and CX3CR1-directed migration was attenuated by M3. In vivo, adenoviruses encoding M3 (AdM3) or green fluorescence protein (AdGFP; control) were infused systemically into apolipoprotein (apo)-E-/- mice. Two models of atherosclerosis development were used in which the rate of plaque progression was varied by diet including: (1) a ‘rapid promotion’ model (6-week high-fat-fed) and (2) a ‘slow progression’ model (12-week chow-fed). Plasma chemokine activity was suppressed in AdM3-infused mice as indicated by significantly less monocyte migration towards AdM3 mouse plasma ex vivo (29.56%, p = 0.014). In the ‘slow progression’ model AdM3 mice had reduced lesion area (45.3%, p = 0.035) and increased aortic smooth muscle cell α-actin expression (60.3%, p = 0.014). The reduction in lesion size could not be explained by changes in circulating inflammatory monocytes as they were higher in the AdM3 group. In the ‘rapid promotion’ model AdM3 mice had no changes in plaque size but reduced plaque macrophage content (46.8%, p = 0.006) and suppressed lipid deposition in thoracic aortas (66.9%, p<0.05). There was also a reduction in phosphorylated p65, the active subunit of NF-κb, in the aortas of AdM3 mice (37.3%, p<0.0001). M3 inhibited liver CCL2 concentrations in both models with no change in CCL5 or systemic chemokine levels. These findings show M3 causes varying effects on atherosclerosis progression and plaque composition depending on the rate of lesion progression. Overall, our studies support a promising role for chemokine inhibition with M3 for the treatment of atherosclerosis.

Metabolism of 20(S)-Ginsenoside Rg₂ by Rat Liver Microsomes: Bioactivation to SIRT1-Activating Metabolites.

20(S)-Ginsenoside Rg2 (1) has recently become a hot research topic due to its potent bioactivities and abundance in natural sources such as the roots, rhizomes and stems-leaves of Panax ginseng. However, due to the lack of studies on systematic metabolic profiles, the prospects for new drug development of 1 are still difficult to predict, which has become a huge obstacle for its safe clinical use. To solve this problem, investigation of the metabolic profiles of 1 in rat liver microsomes was first carried out. To identify metabolites, a strategy of combined analyses based on prepared metabolites by column chromatography and ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was performed. As a result, four metabolites M1–M4, including a rare new compound named ginsenotransmetin A (M1), were isolated and the structures were confirmed by spectroscopic analyses. A series of metabolites of 1, MA–MG, were also tentatively identified by UPLC-Q-TOF/MS in rat liver microsomal incubate of 1. Partial metabolic pathways were proposed. Among them, 1 and its metabolites M1, M3 and M4 were discovered for the first time to be activators of SIRT1. The SIRT1 activating effects of the metabolite M1 was comparable to those of 1, while the most interesting SIRT1 activatory effects of M3 and M4 were higher than that of 1 and comparable with that of resveratrol, a positive SIRT1 activator. These results indicate that microsome-dependent metabolism may represent a bioactivation pathway for 1. This study is the first to report the metabolic profiles of 1 in vitro, and the results provide an experimental foundation to better understand the in vivo metabolic fate of 1.

Anti-inflammatory and Anti-oxidative Activities of Paeonol and Its Metabolites Through Blocking MAPK/ERK/p38 Signaling Pathway.

The possible protective and curative effects of paeonol on carrageenan-induced acute hind paw edema in rats and dextran sulfate sodium (DSS)-induced colitis in mice have been evaluated. After oral administration, paeonol (20 and 40 mg/kg) reduced the edema increase in paw volumes and also the development of DSS-induced murine colitis. Furthermore, anti-inflammatory and anti-oxidant activities of paeonol (1) together with its 10 metabolites (M2~M11) were investigated by using in vitro anti-inflammatory and anti-oxidant assays. M3 and M11 exhibited significant 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities (with EC50 values of 93.44 and 23.24 μM, respectively). All the metabolites except M8 showed hydroxyl radical scavenging activities, and M3 and M11 were the most potent agents (with EC50 values of 336.02 and 124.05 μM, respectively). Inhibitory effects of paeonol, M2~M11 on the overproduction of nitric oxide (NO), and the release of TNF-α were also tested. M3 and M11 potently inhibited lipopolysaccharide (LPS)-induced overproduction of NO in macrophage RAW 264.7. Western blot results demonstrated that paeonol, M3, and M11 downregulated the high expression of inducible nitric oxide synthase (iNOS) and COX-2 proteins, and the effects of M3 and M11 were more potent when compared with paeonol. These findings indicated that paeonol may play anti-inflammatory and anti-oxidant roles by changing to its active metabolites after absorption. In addition, further investigations on the mechanism showed that paeonol, M3, and M11 blocked the phosphorylation of MAPK/ERK 1/2 and p38, whereas they showed no effect on the phosphorylation of JNK. The above results suggested that pre-treatment with paeonol might be an effective therapeutic intervention against inflammatory diseases including colitis.

Fasudil, a rho kinase inhibitor, limits motor neuron loss in experimental models of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder with no effective treatment. Fasudil hydrochloride (fasudil), a potent rho kinase (ROCK) inhibitor, is useful for the treatment of ischaemic diseases. In previous reports, fasudil improved pathology in mouse models of Alzheimer's disease and spinal muscular atrophy, but there is no evidence in that it can affect ALS. We therefore investigated its effects on experimental models of ALS. In mice motor neuron (NSC34) cells, the neuroprotective effect of hydroxyfasudil (M3), an active metabolite of fasudil, and its mechanism were evaluated. Moreover, the effects of fasudil, 30 and 100 mg·kg(-1), administered via drinking water to mutant superoxide dismutase 1 (SOD1(G93A)) mice were tested by measuring motor performance, survival time and histological changes, and its mechanism investigated. M3 prevented motor neuron cell death induced by SOD1(G93A). Furthermore, M3 suppressed both the increase in ROCK activity and phosphorylated phosphatase and tensin homologue deleted on chromosome 10 (PTEN), and the reduction in phosphorylated Akt induced by SOD1(G93A). These effects of M3 were attenuated by treatment with a PI3K inhibitor (LY294002). Moreover, fasudil slowed disease progression, increased survival time and reduced motor neuron loss, in SOD1(G93A) mice. Fasudil also attenuated the increase in ROCK activity and PTEN, and the reduction in Akt in SOD1(G93A) mice. These findings indicate that fasudil may be effective at suppressing motor neuron degeneration and symptom progression in ALS. Hence, fasudil may have potential as a therapeutic agent for ALS treatment.

Tu1600 Use of Divergent Effects of M3 and M1 Muscarinic Receptor (MR) Ablation on Murine Colon Neoplasia to Identify M3R-Regulated Changes in Gene and Protein Expression

PPZ-induced cell apoptosis. Further more, we found that PPZ significantly reduced secretion of the pro-inflammatory cytokine, IL-6, from gastric cancer cells, while not affect the gastric epithelia cells. The anti-tumor effect of PPZ was consistent with a clear inhibition of IL-6/ STAT3 signaling pathway in gastric cancer cells. The downstream genes of STAT3, which regulate cell growth or cell cycle, were also downregulated. Together, this study suggests that the direct and selective antitumor effects of PPIs may be involved with the IL-6/ STAT3 pathway and indicates the potential use of PPIs as antineoplastic agents towards gastric cancers.

Huperzine A derivative M3 protects PC12 cells against sodium nitroprusside-induced apoptosis

To investigate the effects of M3, a derivative of huperzine A, on the apoptosis induced by sodium nitroprusside (SNP) in PC12 cells. Cell viability was detected using MTT method. Apoptosis was examined with annexin V/prodium iodide (PI) stain. The levels of reactive oxygen species (ROS) were measured using fluorophotometric quantitation. The amount of malonaldehyde (MDA) was determined with MDA detection kits. The expression of caspase-3 and Hsp70 were analyzed using Western blotting. Exposure of PC12 cells to SNP (200 μmol/L) for 24 h decreased the cell viability to 69.0% of that in the control group. Pretreatment with M3 (10 μmol/L) or huperzine A (10 μmol/L) significantly protected the cells against SNP-induced injury and apoptosis; the ratio of apoptotic bodies in PC12 cells was decreased from 27.3% to 15.0%. Pretreatment with M3 (10 μmol/L) significantly decreased ROS and MDA levels, and increased the expression of Hsp70 in the cells. Quercetin (10 μmol/L) blocked the protective effect of M3, while did not influence on that of huperzine A. M3 protects PC12 cells against SNP-induced apoptosis, possible due to ROS scavenging and Hsp70 induction.

Going the Right Distance

Keratinocytes migrate over injured skin to form new epidermis. Acetylcholine, acting through muscarinic receptors, influences keratinocyte migration and wound healing; however, the detailed mechanisms remain incompletely understood. Chernyavsky et al. used a model of wound healing in which keratinocytes migrated into agarose gels, a monolayer wounding assay, and in vivo knockout experiments to investigate the role of M 3 and M 4 acetylcholine receptors in keratinocyte migration. Human keratinocytes transfected with antibodies against M 3 small, interfering RNA (siRNA) migrated further into gels than did control cells, as did keratinocytes from mice lacking M 3 , whereas keratinocytes transfected with antibodies against M 4 siRNA (or from mice lacking M 4 ) showed decreased migration. In vivo experiments also indicated that M 4 enhanced and M 3 inhibited migration. Pharmacologic analysis indicated that the effects of M 3 (which acts through the Gα q/11 family of heterotrimeric guanosine triphosphate-binding proteins) involved calcium mobilization and subsequent activation of a guanylate kinase-cGMP (guanosine 3′,5′-monophosphate)-protein kinase G signaling pathway. The effects of M 4 (which acts through Gα i/o ) were mediated through inhibition of the adenylate cyclase-cAMP (adenosine 3′,5′-monophosphate)-protein kinase A cascade. The M 3 and M 4 pathways converged on Rho and Rho kinase. Pharmacologic and siRNA analysis, as well as analysis of knockout mice, indicated that M 4 promoted expression of integrins that mediate adhesion to proteins over which keratinocytes migrate during wound healing, whereas M 3 promoted expression of integrins found at cell-cell contact sites. Further, antibodies to the "migratory integrins" reduced in vitro migration of keratinocytes lacking M 3 , whereas antibodies to the "sedentary integrins" reduced migration of keratinocytes lacking M 4 . Thus, the authors propose that opposing inhibitory and stimulatory pathways mediated through the M 3 and M 4 receptors regulate keratinocyte migration during wound healing. A. I. Chernyavsky, J. Arredondo, J. Weiss, E. Karlsson, S. A. Grando, Novel signaling pathways mediating reciprocal control of keratinocyte migration and wound epithelialization through M 3 and M 4 muscarinic receptors. J. Cell Biol. 166 , 261-272 (2004). [Abstract] [Full Text]

Ferroelastic phase transitions in Rb2KM3+F6 elpasolites

The effect of M3+ ion substitution on the physical properties of Rb2KM3+F6 (M3+ =Ga, Fe, Sc, In, Lu, Er, Ho, Tb) series with elpasolite structure was studied by DTA under hydrostatic pressure, calorimetric, X-ray, elastic and inelastic neutron scattering measurements. There exists a strong dependence of both type and succession of ferroelastic phase transitions on the M3+ ion size. Hydrostatic pressure effect was found partially inconsistent with chemical pressure. Possible models of phase transition mechanism were considered. It was supposed that anharmonic F atom vibrations could play a great role in phase transitions of the series.

Metamorphic evolution of exhumed middle to lower crustal rocks in the Mojave Extensional Belt, southern California, USA

The Waterman Metamorphic Complex of the central Mojave Desert was exposed as a consequence of early Miocene detachment‐dominated extension. However, it has evidence consistent with a more extensive geological history that involves collision of a crustal fragment(s), tectonic thickening by overthrusting and two periods of extension. The metamorphic complex contains granitoid intrusives and felsic mylonitic gneisses as well as polymetamorphic rocks that include marble, calc‐silicate, quartzite. mafic granulite, pyribolite, amphibolite, migmatite and biotite schist. The latter group of rocks was affected by an initial series of high‐grade metamorphic events (M1 and M2) and a localized lower grade overprint (M3). The initial metamorphism (M1) can be separated into two stages along its high‐grade P–T path: M1a, a granulite facies metamorphism at 800–850° C and 7.5–9 kbar and Mlb, an upper amphibolite facies overprint at 750–800° C and 10–12 kbar. M1a developed mineral assemblages and textures consistent with granulite facies conditions at a reduced activity of H2O and is associated with intense ductile deformation (D1) and minor local partial melting. M1b overprinted the granulite assemblages with a series of hydrous phases under conditions of increasing pressure and H2O activity and is accompanied by little or no deformation. M2 developed at lower pressures and temperatures (650–750° C, 4.5–5.5 kbar) and is distinguished by a second local overprint of hydrous phases that reflects an input of aqueous fluids probably associated with the intrusion of a series of granitic dykes and veins. Effects of M3 are confined to the Mitchel detachment zone, an anastomosing early Miocene detachment fault, and are characterized by local ductile/brittle deformation (D2) of the pre‐existing high‐grade rocks and granitoid intrusives and by the production of mylonites and mylonitic gneisses under greenschist facies conditions (300–350° C, 3–5 kbar). The initial overprint (M1a) represents metamorphism, devolatilization and minor partial melting of supracrustal rocks under granulite facies conditions as a consequence of tectonic and, possibly, magmatic thickening. The increasing pressure transition of M1a to M1b reflects a period of continued compressional tectonism, thrusting and influx of H2O, in part, locally related to crystallization of partial melts. The near isothermal decompression between M1b and M2 probably represents a pre‐112‐Ma extensional episode that may have been the result of a decompressional readjustment of a thickened crust. Following the initial extensional event, the metamorphic complex remained at depths of 10–17 km for at least 90 Ma until it was uplifted following Miocene extension. M3 develops locally in response to this second extensional period resulting from the early Miocene detachment faulting.

Proterozoic granulite facies metamorphism in the southeastern Reynolds Range, central Australia: geological context, P–T path and overprinting relationships

In the southeastern Reynolds Range, central Australia, a low‐P granulite facies metamorphism affected two sedimentary sequences: the Lander Rock Beds and the Reynolds Range Group. In the context of the whole of the Reynolds Range and the adjacent Anmatjira Range, this metamorphism is M3 in a sequence M1–4 that occurred over a period of 250 Ma. In particular, M1 affected the Lander Rock Beds prior to the deposition of the Reynolds Group. M3 has an areally restricted, high‐grade area in the southeastern Reynolds Range, affecting both the Reynolds Range Group and the underlying Lander Rock Beds. The effects of M3 are characterized by spinel + quartz‐bearing peak metamorphic assemblages in metapelites, which imply peak conditions of ≥750°C and 4.5 ± 1 kbar, and involved isobaric cooling or compression with cooling. It is concluded that one of a series of thermal perturbations caused by thinning of mantle lithosphere contemporaneous with crustal thickening was responsible for M3. In the southeastern Reynolds Range, evidence of both the unconformity between the two rock groups and previous metamorphism/deformation has been completely erased by recrystallization during M3–D3.

The Ashe Metamorphic Suite, Northwest North Carolina; metamorphism and observations on geologic history

The Ashe Metamorphic Suite (AMS) consists of amphibolite schist and gneiss (metabasalts), pelitic schist and gneiss (metasediments), and ultramafic rocks. Evidence for four metamorphic events (M1, M2, M3, M4) exists. M1 affected only the ultramafic rocks in the suite. The peak metamorphism, M2, was an upper amphibolite facies event that affected all lithologies in the AMS during the Ordovician Taconic Orogeny. Three M2 zones of the amphibolite facies are recognizable in the pelitic rocks. Conditions during M2 are estimated to have been P &gt; 7 kb and T = 700 degrees C. The effects of M3 and M4 are minor in the pelitic and mafic rocks and identified with the growth of chlorite upon partial hydration of these rocks. There are at least four possible plate tectonic sites for the origin of the AMS: (1) on a passive, ensialic margin, (2) on a passive, ensimatic or transitional margin, (3) on an active, ensimatic margin, and (4) in an ensialic or ensimatic, back-arc basin.--Modified journal abstract.

Effect of m3 gene on the development of phage P22.

Mutation of the gene m3 of phage P22 causes permanent depression of macromolecular synthesis in the infected host and thus inhibits phage development as indicated by burst size and lysozyme production. The permanent depression of macromolecular synthesis is most probably due to blockage of the transport process. The m3 allele is dominant over m+. m3 allows some transcription of phage genes (however, the difference between early and late function is not clear). The inhibitory effect of m3 on DNA synthesis may be indirect.