RESUMO
Plant growth and development are significantly hampered in saline environments, limiting agricultural productivity. Thus, it is crucial to unravel the mechanism underlying plant responses to salt stress. ß-1,4-Galactan (galactan), which forms the side chains of pectic rhamnogalacturonan I, enhances plant sensitivity to high-salt stress. Galactan is synthesized by GALACTAN SYNTHASE1 (GALS1). We previously showed that NaCl relieves the direct suppression of GALS1 transcription by the transcription factors BPC1 and BPC2 to induce the excess accumulation of galactan in Arabidopsis (Arabidopsis thaliana). However, how plants adapt to this unfavorable environment remains unclear. Here, we determined that the transcription factors CBF1, CBF2, and CBF3 directly interact with the GALS1 promoter and repress its expression, leading to reduced galactan accumulation and enhanced salt tolerance. Salt stress enhances the binding of CBF1/CBF2/CBF3 to the GALS1 promoter by inducing CBF1/CBF2/CBF3 transcription and accumulation. Genetic analysis suggested that CBF1/CBF2/CBF3 function upstream of GALS1 to modulate salt-induced galactan biosynthesis and the salt response. CBF1/CBF2/CBF3 and BPC1/BPC2 function in parallel to regulate GALS1 expression, thereby modulating the salt response. Our results reveal a mechanism in which salt-activated CBF1/CBF2/CBF3 inhibit BPC1/BPC2-regulated GALS1 expression to alleviate galactan-induced salt hypersensitivity, providing an activation/deactivation fine-tune mechanism for dynamic regulation of GALS1 expression under salt stress in Arabidopsis.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Estresse Salino , Adaptação Fisiológica , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Temperatura Baixa , Regulação da Expressão Gênica de Plantas , Regiões Promotoras Genéticas/genética , Transativadores/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Estresse Salino/genéticaRESUMO
BACKGROUND: Structured examination routines have been developed as educational resources for musculoskeletal clinical skills teaching, including Gait-Arms-Legs-Spine (GALS), Regional Examination of the Musculoskeletal System (REMS) and paediatric GALS (pGALS). In this study, we aimed to assess the awareness and use of these examination routines in undergraduate medical teaching in UK medical schools and UK postgraduate clinical practice. METHODS: Electronic questionnaires were distributed to adult and paediatric musculoskeletal teaching leads at UK medical schools and current UK doctors in training. RESULTS: Responses were received from 67 tutors representing teaching at 22/33 [67 %] of all UK medical schools, and 70 trainee doctors across a range of postgraduate training specialities. There was widespread adoption, at responding medical schools, of the adult examination routines within musculoskeletal teaching (GALS: 14/16 [88 %]; REMS: 12/16 [75 %]) and assessment (GALS: 13/16 [81 %]; REMS: 12/16 [75 %]). More trainees were aware of GALS (64/70 [91 %]) than REMS (14/67 [21 %]). Of the 39 trainees who used GALS in their clinical practice, 35/39 [90 %] reported that it had improved their confidence in musculoskeletal examination. Of the 17/22 responding medical schools that included paediatric musculoskeletal examination within their curricula, 15/17 [88 %] used the pGALS approach and this was included within student assessment at 4 medical schools. CONCLUSIONS: We demonstrate the widespread adoption of these examination routines in undergraduate education and significant uptake in postgraduate clinical practice. Further study is required to understand their impact upon clinical performance.
Assuntos
Competência Clínica , Educação de Graduação em Medicina/métodos , Doenças Musculoesqueléticas/diagnóstico , Exame Físico , Adulto , Feminino , Humanos , Masculino , Inquéritos e Questionários , Ensino , Reino UnidoRESUMO
The unique biological and rheological properties make hyaluronic acid a sought-after material for medicine and cosmetology. Due to very high purity requirements for hyaluronic acid in medical applications, the profitability of streptococcal fermentation is reduced. Production of hyaluronic acid by recombinant systems is considered a promising alternative. Variations in combinations of expressed genes and fermentation conditions alter the yield and molecular weight of produced hyaluronic acid. This review is devoted to the current state of hyaluronic acid production by recombinant bacterial and fungal organisms.
RESUMO
Conjugated linoleic acid (CLA) isomers are potent health-promoting fatty acids. This study evaluated the probiotic properties of 10 strains of high CLA-producing lactic acid bacteria (LAB) isolated from Jeot-gal, a high-salt, fermented seafood. Two isolates, Lactiplantibacillus plantarum JBCC105683 and Lactiplantibacillus pentosus JBCC105676, produced the largest amounts of CLA (748.8 and 726.9 µg/mL, respectively). Five isolates, L. plantarum JBCC105675, L. pentosus JBCC105676, L. pentosus JBCC105674, L. plantarum JBCC105683, and Lactiplantibacillus paraplantarum JBCC105655 synthesized more cis-9, trans-11-CLA than trans-10, cis-12-CLA (approximately 80:20 ratio). All the strains survived severe artificial acidic environments and showed antimicrobial activity and strong adhesion capability to Caco-2 cells as compared to the commercial strain Lactocaseibacillus rhamnosus GG. Among them, Pediococcus acidilactici JBCC105117, L. paraplantarum JBCC105655, and L. plantarum JBCC105683 strongly stimulated the immunological regulatory gene PMK-1 and the host defense antimicrobial peptide gene clec-60 in Caenorhabditis elegans. Moreover, three strains showed a significant induction of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, IL-12, and IL-10 production in RAW 264.7 macrophages, indicating that they were promising candidates for probiotics with high CLA-converting activity. Our results indicate that the newly isolated CLA-producing LAB might be useful as a functional probiotic with beneficial health effects that modulate the immune system.
RESUMO
Salinity severely reduces plant growth and limits agricultural productivity. Dynamic changes and rearrangement of the plant cell wall is an important response to salt stress, but relatively little is known about the biological importance of specific cell wall components in the response. Here, we demonstrate a specific function of ß-1,4-galactan in salt hypersensitivity. We found that salt stress induces the accumulation of ß-1,4-galactan in root cell walls by up regulating the expression of GALACTAN SYNTHASE 1 (GALS1), which encodes a ß-1,4-galactan synthase. The accumulation of ß-1,4-galactan negatively affects salt tolerance. Exogenous application of D-galactose (D-Gal) causes an increase in ß-1,4-galactan levels in the wild type and GALS1 mutants, especially in GALS1 overexpressors, which correlated with the aggravated salt hypersensitivity. Furthermore, we discovered that the BARLEY B RECOMBINANT/BASIC PENTACYSTEINE transcription factors BPC1/BPC2 positively regulate plant salt tolerance by repressing GALS1 expression and ß-1,4-galactan accumulation. Genetic analysis suggested that GALS1 is genetically epistatic to BPC1/BPC2 with respect to the control of salt sensitivity as well as accumulation of ß-1,4-galactan. Taken together, our results reveal a new regulatory mechanism by which ß-1,4-galactan regulated by the BPC1/BPC2-GALS1 module aggravates salt sensitivity in Arabidopsis thaliana.