Improved chloroplast Pi allocation helps sustain electron transfer to enhance photosynthetic low-phosphorus tolerance of wheat.

Phosphorus (P) deficit limits high wheat (Triticum aestivum L.) yields. Breeding low-P-tolerant cultivars is vital for sustainable agriculture and food security, but the low-P adaptation mechanisms are largely not understood. Two wheat cultivars, ND2419 (low-P-tolerant) and ZM366 (low-P-sensitive) were used in this study. They were grown under hydroponic conditions with low-P (0.015 mM) or normal-P (1 mM). Low-P suppressed biomass accumulation and net photosynthetic rate (A) in both cultivars, whereas ND2419 was relatively less suppressed. Intercellular CO2 concentration did not decrease with the decline of stomatal conductance. Additionally, maximum electron transfer rate (Jmax) decreased sooner than maximum carboxylation rate (Vcmax). Results indicate that impeded electron transfer is directly responsible for decreased A. Under low-P, ND2419 exhibited greater PSII functionality (potential activity (Fv/Fo), maximum quantum efficiency (Fv/Fm), photochemical quenching (qL) and non-photochemical quenching (NPQ) required for electron transfer than ZM366, resulting more ATP for Rubisco activation. Furthermore, ND2419 maintained higher chloroplast Pi concentrations by enhancing chloroplast Pi allocation, compared with ZM366. Overall, the low-P-tolerant cultivar sustained electron transfer under low-P by enhancing chloroplast Pi allocation, allowing more ATP synthesis for Rubisco activation, ultimately presenting stronger photosynthesis capacities. The improved chloroplasts Pi allocation may provide new insights into improve low-P tolerance.

Discovery of pentaene polyols by the activation of an enediyne gene cluster: biosynthetic implications for 9-membered enediyne core structures.

The identification and characterization of enediyne polyketide synthases (PKSEs) revealed that PKSE-bound polyene is a common intermediate, while its subsequent tailoring steps to enediyne cores remain obscure. Herein, we report pentaene polyols 5-7 and cinnamic acid derivatives 8 and 9 biosynthesized from an activated enediyne biosynthetic gene cluster in Streptomyces sp. CB02130. The C-1027 pksE could partially complement production of these polyene polyols in a CB02130 mutant where the native pksE is inactivated. The yields of 5-7 were improved by increasing the cellular pool of l-Phe through either gene inactivation of a prephenate dehydrogenase WlsPDH or supplementation of l-Phe. A flexible ammonia lyase WlsC4 is responsible for biosynthesis of 8 and 9 from l-Phe. The co-localization of wlsPDH and PKSE gene cassette supports their close evolutionary relationships and an enediyne genome mining strategy using WlsPDH. These findings not only provide a facile approach to activate silent enediyne BGCs, but suggest that a polyene epoxide intermediate may be formed for construction of 9-membered enediyne macrocycles.

Low red/far-red ratio can induce cytokinin degradation resulting in the inhibition of tillering in wheat (Triticum aestivum L.).

Shoot branching is inhibited by a low red/far-red ratio (R/FR). Prior studies have shown that the R/FR suppressed Arabidopsis thaliana branching by promotes bud abscisic acid (ABA) accumulation directly. Given that wheat tiller buds are wrapped in leaf sheaths and may not respond rapidly to a R/FR, systemic cytokinin (CTK) may be more critical. Here, systemic hormonal signals including indole-3-acetic acid (IAA), gibberellins (GA) and CTK and bud ABA signals in wheat were tested under a low R/FR. The results showed that a low R/FR reduced the percentage of tiller occurrence of tiller IV and the tiller number per plant. The low R/FR did not rapidly induced ABA accumulation in the tiller IV because of the protection of the leaf sheath and had little effect on IAA content and signaling in the tiller nodes. The significant change in the CTK levels was observed earlier than those of other hormone (ABA, IAA and GA) and exogenous cytokinin restored the CTK levels and tiller number per plant under low R/FR conditions. Further analysis revealed that the decrease in cytokinin levels was mainly associated with upregulation of cytokinin degradation genes (TaCKX5, TaCKX11) in tiller nodes. In addition, exposure to a decreased R/FR upregulated the expression of GA biosynthesis genes (TaGA20ox1, TaGA3ox2), resulting in elevated GA levels, which might further promote CTK degradation in tiller nodes and inhibit tillering. Therefore, our results provide evidence that the enhancement of cytokinin degradation is a novel mechanism underlying the wheat tillering response to a low R/FR.

Lipopeptide surfactin ameliorates the cell uptake of platensimycin and enhances its therapeutic effect on treatment of MRSA skin infection.

OBJECTIVES: The rapid development of drug-resistant bacteria, especially MRSA, poses severe threats to global public health. Adoption of antibiotic adjuvants has proved to be one of the efficient ways to solve such a crisis. Platensimycin and surfactin were comprehensively studied to combat prevalent MRSA skin infection. METHODS: MICs of platensimycin, surfactin or their combinations were determined by resazurin assay, while the corresponding MBCs were determined by chequerboard assay. Growth inhibition curves and biofilm inhibition were determined by OD measurements. Membrane permeability analysis was conducted by propidium iodide staining, and morphological characterizations were performed by scanning electron microscopy. Finally, the therapeutic effects on MRSA skin infections were evaluated in scald-model mice. RESULTS: The in vitro assays indicated that surfactin could significantly improve the antibacterial performance of platensimycin against MRSA, especially the bactericidal activity. Subsequent mechanistic studies revealed that surfactin not only interfered with the biofilm formation of MRSA, but also disturbed their cell membranes to enhance membrane permeability, and therefore synergistically ameliorated MRSA cellular uptake of platensimycin. Further in vivo assessment validated the synergistic effect of surfactin on platensimycin and the resultant enhancement of therapeutical efficacy in MRSA skin-infected mice. CONCLUSIONS: The combination of effective and biosafe surfactin and platensimycin could be a promising and efficient treatment for MRSA skin infection, which could provide a feasible solution to combat the major global health threats caused by MRSA.

Musculoskeletal ultrasound and its application in sports medicine / A ultrassonografia musculoesquelética e sua aplicação na medicina do esporte / El ultrasonido musculoesquelético y su aplicación en la medicina del deporte

ABSTRACT Introduction: Musculoskeletal ultrasound is a clinical auxiliary examination for the diagnosis of musculoskeletal system injuries by ultrasound imaging technology. Objective: To explore the real time application value of musculoskeletal ultrasound in exercise. Methods: The MSKUS technique was used to diagnose and classify the types, positions and degrees of sports injuries. Results: A total of 35 athletes received a MSKUS diagnosis; 2 athletes were recommended to withdraw from competition after the diagnosis and return to China for treatment. Among the athletes, 9 cases (25.71%) suffered muscle injury, 22 (62.86%) suffered tendon, ligament and fascia injury, 2 (5.71%) suffered bone and cartilage injury, and 2 (5.71%) suffered bursitis. The main site of injury was the lower extremity (74.29%). Most of the injuries were mild, and only 2 cases were severe. Conclusions: Musculoskeletal ultrasound has certain advantages in the real-time diagnosis of tendons, ligaments and soft tissue in the field. Using musculoskeletal ultrasounds, doctors can assess the injury situation more quickly and accurately, and choose the next steps concerning exercise prescription and a rehabilitation treatment plan more effectively. Musculoskeletal ultrasound is real time, reliable and convenient, and has application value in sports. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Introdução: A ultrassonografia musculoesquelética é um exame clínico auxiliar para o diagnóstico de lesões do sistema musculoesquelético através da tecnologia por imagens ultrassonográficas. Objetivo: Explorar o valor de aplicação em tempo real da ultrassonografia musculoesquelético para exercícios. Métodos: A técnica USME foi utilizada para o diagnóstico e a classificação de tipos, posições e graus de lesão causadas pela prática do esporte. Resultados: Um total de 35 atletas receberam diagnósticos por USME; 2 atletas foram recomendados a se retirarem da competição após o diagnóstico e voltarem para a China para tratamento. Entre os atletas, 9 eram casos (25,71%) de lesão muscular, 22 (62,86%) eram casos de lesão de tendão, ligamento e fáscia, 2 (5,71%) sofriam de lesões ósseas e de cartilagem, e 2 (5,71%) sofriam de bursite. O local principal das lesões era a extremidade inferior (74,29%). A maioria das lesões eram leves, e apenas dois casos eram graves. Conclusões: A ultrassonografia musculoesquelética apresenta certas vantagens no diagnostico em tempo real de tendões, ligamentos e tecido mole na área. Com a ultrassonografia musculoesquelética, médicos podem avaliar a situação da lesão com maior rapidez e precisão, e escolher os próximos passos quanto a prescrição de exercícios e um plano de tratamento de reabilitação com maior eficácia. A ultrassonografia musculoesquelética é feita em tempo real, é confiável e conveniente, e tem um valor de aplicação para os esportes. Nível de evidência II; Estudos terapêuticos - investigação de resultados de tratamento.

RESUMEN Introducción: El ultrasonido musculoesquelético es un examen clínico auxiliar para el diagnóstico de lesiones del sistema musculoesquelético a través de la tecnología por imágenes ultrasonográficas. Objetivo: Explorar el valor de aplicación en tiempo real del ultrasonido musculoesquelético para ejercicios. Métodos: La técnica USME se utilizó para el diagnóstico y clasificación de tipos, posiciones y grados de lesión causadas por la práctica de deporte. Resultados: Un total de 35 atletas recibieron diagnósticos por USME; se recomendó a 2 atletas que se retiraran de la competición tras el diagnóstico y que volvieran a China para tratamiento. Entre los atletas, 9 (25,71%) eran casos de lesión muscular, 22 (62,86%) eran casos de lesión de tendón, ligamento y fascia, 2 (5,71%) sufrían de lesiones óseas y de cartílago, y 2 (5,71%) sufrían de bursitis. El sitio principal de lesiones era la extremidad inferior (74,29%). La mayoría de las lesiones eran leves, y solo dos casos eran graves. Conclusiones: El ultrasonido musculoesquelético presenta ciertas ventajas en el diagnóstico en tiempo real de tendones, ligamentos y tejido blanco en el área. Con el ultrasonido musculoesquelético, médicos pueden evaluar la situación de la lesión con mayor rapidez y precisión, y elegir los próximos pasos cuanto a la prescripción de ejercicios y un plan de tratamiento de rehabilitación con mayor eficacia. El ultrasonido musculoesquelético se hace en tiempo real, es confiable y conveniente, y tiene un valor de aplicación para los deportes. Nivel de evidencia II; Estudios terapéuticos - investigación de resultados de tratamiento.