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Legumes form tripartite symbiotic associations with nodule- in inducing rhizobia and vesicular-arbuscular mycorrhizal fungi. Co-inoculation of soybean (Glycine max [L.] Merr.) roots with Bradyrhizobium japonicum 61-A-101 considerably enhanced colonization by the mycorrhizal fungus Glomus mosseae. A similar stimulatory effect on mycorrhizal colonization was also observed in nonnodulating soybean mutants when inoculated with Bradyrhizobium japonicum and in wild-type soybean plants when inoculated with ineffective rhizobial strains, indicating that a functional rhizobial symbiosis is not necessary for enhanced mycorrhiza formation. Inoculation with the mutant Rhizobium sp. NGR delta nodABC, unable to produce nodulation (Nod) factors, did not show any effect on mycorrhiza. Highly purified Nod factors also increased the degree of mycorrhizal colonization. Nod factors from Rhizobium sp. NGR234 differed in their potential to promote fungal colonization. The acetylated factor NodNGR-V (MeFuc, Ac), added at concentrations as low as 10(-9) M, was active, whereas the sulfated factor, NodNGR-V (MeFuc, S), was inactive. Several soybean flavonoids known to accumulate in response to the acetylated Nod factor showed a similar promoting effect on mycorrhiza. These results suggest that plant flavonoids mediate the Nod factor-induced stimulation of mycorrhizal colonization in soybean roots

In order to explore the effect of stratified evolution and delamination on the load capacity and service life of the composite materials under the four-point bending loading, the artificial tectonic defects of the different positions were set up. The four-point bending test was carried out, and the whole process was recorded by acoustic emission, and the damage degree of the composite layer was judged by the impact accumulation of the specimen - time-amplitude history chart, load-time-relative energy history chart, acoustic emission impact signal positioning map. The results show that the stratified defects near the surface of the specimen accelerate the process of material failure and expansion. The location of the delamination defects changes the bending performance of the composites to a great extent. The closer the stratification defects are to the surface of the specimen, the greater the damage, the worse the service capacity of the specimen.

Isoforms of endochitinase in soybean were studied in relation to root symbiosis. Five selected cultivars differing in their nodulation potential were inoculated with two strains of Bradyrhizobium japonicum, the broad host-range Rhizobium sp. NGR234, and with the mycorrhizal fungus Glomus mosseae. Total chitinase activity in nodules was up to 7-fold higher than in uninoculated roots and in mycorrhizal roots. The chitinase activity in nodules varied depending on the strain—cultivar combination. On semi-native polyacrylamide gels, four acidic isoforms were identified. Two isoforms (CH 2 and CH 4) were constitutively present in all analysed tissues. The other two isoforms (CH 1 and CH 3) were strongly induced in nodules and were stimulated in mycorrhizal roots as compared to uninoculated roots. The induction of CH 1 varied in nodules depending on the soybean cultivar. This isoform was also stimulated in uninfected roots when they were treated with tri-iodobenzoic acid, rhizobial lipochitooligosaccharides (Nod factors) and chitotetraose. CH 3 was not affected by these stimuli indicating that this isoform could represent a marker for enzymes induced in later stages of the symbiotic interactions.

Roots of Lablab purpureus (L.) Sweet were treated with tri-iodobenzoic acid (TIBA), kinetin or with nodulation factors (Nod factors) purified from Rhizobium sp. NGR234 and grown in the presence of a mycorrhizal inoculum (Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe. Colonization by the mycorrhizal fungus was increased from <30% to c. 65% of root length when roots were treated with these growth regulators. Moreover, treatment of mycorrhizal L. purpureus roots with Nod factors or TIBA strongly induced sporocarp formation of Glomus mosseae. In parallel, the pool size of the fungal disaccharide trehalose was significantly affected in roots treated with TIBA and Nod factors alone, and with TIBA combined with all effectors, and increased from 0·06 mg g−1 d. wt in control roots to up to 1·7 mg g−1 d. wt (TIBA+kinetin). Conversely, the sucrose pool decreased from 5% d. wt to less than a half in roots treated with Nod factors. Activities of trehalase were significantly enhanced in mycorrhizal roots by the treatment with Nod factors or TIBA. When Nod factors and TIBA were added in combination, these activities were strongly enhanced suggesting synergism between these growth regulators.

Rhizobial Nod factors (NFs) function as nodulation signals that trigger symbiotic responses of leguminous host plants. NFs consist of a chitin oligomer backbone carrying a fatty acid at the non-reducing end. Depending on the rhizobial strain, NFs carry additional substituents, which may determine host specificity. Transgenic suspension-cultured soybean (Glycine max [L.] Merr.) cells expressing aequorin have been used to record cytosolic [Ca2+] changes upon treatment with purified NFs and chitin fragments. Both compounds elicited an increase of cytosolic [Ca2+] at nanomolar concentrations. The shape and amplitude of cytosolic [Ca2+] changes was similar to the response elicited by un-derivatized chitin oligomers. Cells challenged first with NFs did not respond to a subsequent treatment with chitin oligomers and vice versa. Dose-response experiments showed that un-derivatized chitin oligomers were more active compared with NFs. The capacity of NFs to elicit the calcium response depended on their structure. The presence of reducing end substituents in methylfucosylated NFs from Rhizobium sp. NGR234 and the O-acetyl group at the non-reducing end in NFs from Sinorhizobium meliloti attenuated the activity to cause the calcium changes. The sulfate group in NFs from Rhizobium tropici did not affect the elicitor activity. Pentameric S. meliloti NFs were more active than tetrameric molecules, whereas trimeric or dimeric degradation products were inactive. Substituents in NFs may have the function to avoid stimulation of defense reactions mediated by the perception system for chitin oligomers.

A bstract With data samples collected with the BESIII detector at seven energy points at s = 3 . 68 − 3 . 71 GeV, corresponding to an integrated luminosity of 333 pb − 1 , we present a study of the Λ transverse polarization in the e + e − → Λ Λ ¯ reaction. The significance of polarization by combining the seven energy points is found to be 2.6 σ including the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the Λ Λ ¯ helicity states. The modulus ratio and the relative phase of EM- psionic form factors combined with all energy points are measured to be R Ψ = 0.71 − 0.10 + 0.10 ± 0.03 and ∆Φ Ψ = 23 − 8.0 + 8.8 ± 1.6 ° , where the first uncertainties are statistical and the second systematic.

A bstract Using (10087 ± 44) × 10 6 J / ψ events collected with the BESIII detector at the BEPCII e + e − storage ring at the center-of-mass energy of s = 3.097 GeV, we present a search for the rare semi-muonic charmonium decay J / ψ → D − μ + ν μ + c.c.. Since no significant signal is observed, we set an upper limit of the branching fraction to be B ( J / ψ → D − μ + ν μ + c.c.) < 5.6 × 10 − 7 at 90% confidence level. This is the first search for the weak decay of charmonium with a muon in the final state.

A bstract Using 24.1 fb − 1 of e + e − collision data collected with the BESIII detector at the BEPCII collider, the Born cross sections and effective form factors of the e + e − → Σ + Σ ¯ − reaction are measured. The measurements are performed at center-of-mass energies ranging from 3.510 to 4.951 GeV. No significant evidence for the decay of the charmonium(-like) states, ψ (3770), ψ (4040), ψ (4160), Y (4230), Y (4360), ψ (4415), and Y (4660), into a Σ + Σ ¯ − final state is observed. Consequently, upper limits for the products of the branching fractions and the electronic partial widths at the 90% confidence level are reported for these decays.

The decay D→K-π+ is studied in a sample of quantum-correlated DD¯ pairs, based on a data set corresponding to an integrated luminosity of 2.93 fb-1 collected at the ψ(3770) resonance by the BESIII experiment. The asymmetry between CP-odd and CP-even eigenstate decays into K-π+ is determined to be AKπ=0.132±0.011±0.007, where the first uncertainty is statistical and the second is systematic. This measurement is an update of an earlier study exploiting additional tagging modes, including several decay modes involving a KL0 meson. The branching fractions of the KL0 modes are determined as input to the analysis in a manner that is independent of any strong phase uncertainty. Using the predominantly CP-even tag D→π+π-π0 and the ensemble of CP-odd eigenstate tags, the observable AKππππ0 is measured to be 0.130±0.012±0.008. The two asymmetries are sensitive to rDKπcosδDKπ, where rDKπ and δDKπ are the ratio of amplitudes and phase difference, respectively, between the doubly Cabibbo-suppressed and Cabibbo-favoured decays. In addition, events containing D→K-π+ tagged by D→KS,L0π+π- are studied in bins of phase space of the three-body decays. This analysis has sensitivity to both rDKπcosδDKπ and rDKπsinδDKπ. A fit to AKπ, AKππππ0 and the phase-space distribution of the D→KS,L0π+π- tags yields δDKπ=187.6-9.7+8.9-6.4+5.4∘, where external constraints are applied for rDKπ and other relevant parameters. This is the most precise measurement of δDKπ in quantum-correlated DD¯ decays.

A bstract Using e + e − collision data collected by the BESIII detector at BEPCII corresponding to an integrated luminosity of 30 fb − 1 , we measure Born cross sections and effective form factors for the process e + e − → Ξ 0 Ξ ¯ 0 at forty-five center-of-mass energies between 3.51 and 4.95 GeV. The dressed cross section is fitted, assuming a power-law function plus a charmonium(-like) state, i.e., ψ (3770), ψ (4040), ψ (4160), ψ (4230), ψ (4360), ψ (4415) or ψ (4660). No significant charmonium(-like) state decaying into Ξ 0 Ξ ¯ 0 is observed. Upper limits at the 90% confidence level on the product of the branching fraction and the electronic partial width are provided for each decay. In addition, ratios of the Born cross sections and the effective form factors for e + e − → Ξ 0 Ξ ¯ 0 and e + e − → Ξ − Ξ ¯ + are also presented to test isospin symmetry and the vector meson dominance model.