Quantification and Diversity of Cultivated Bacteria in Root Endosphere and Rhizosphere of Bamboo Species Fargesia nitida in Association with the Tree Succession

Fargesia nitida is a cold-resistant evergreen bamboo and is a pioneer plant in the secondary succession after the native trees were destroyed in the eastern Tibetan Plateau. However, little is known about the effects of this plant on soil conditions and about its microbiomes. Aiming at learning the interactions among the soil characteristics, the plants and the microbes in relation to the plant succession, a study on cultivated microbes associated with the rhizocompartments of F. nitida was performed in the present study to reveal the preference of this plant to the root associated microbes, in comparison with that associated with the successive spruce (Picea asperata Mast.) trees. The results demonstrated that growth of F. nitida could improve the soil nutrient contents, especially increasing total nitrogen, NH4+-N, total carbon, and microbial biomass carbon, and maintained more soil bacteria than the successive spruce trees. Based upon the study of F. nitida root-associated cultivated microbial community, the nutrient improvement in F. nitida growing soils might be from the root endophytic bacteria, which presented greater abundance (3.8, 1.7, and 12.6 folds) than that of bacteria in its rhizosphere, root zone soil, and spruce root zone soil, respectively. Pseudomonas members, especially species related to P. baetica and P. vancouverensis, were strongly selected by F. nitida as root endophytes.

Naringenin regulates production of matrix metalloproteinases in the knee-joint and primary cultured articular chondrocytes and alleviates pain in rat osteoarthritis model

Inflammation of cartilage is a primary symptom for knee-joint osteoarthritis. Matrix metalloproteinases (MMPs) are known to play an important role in the articular cartilage destruction related to osteoarthritis. Naringenin is a plant-derived flavonoid known for its anti-inflammatory properties. We studied the effect of naringenin on the transcriptional expression, secretion and enzymatic activity of MMP-3 in vivo in the murine monosodium iodoacetate (MIA) osteoarthritis model. The assessment of pain behavior was also performed in the MIA rats. The destruction of knee-joint tissues was analyzed microscopically. Moreover, the effect of naringenin was also studied in vitro in IL-1β activated articular chondrocytes. The transcriptional expression of MMP-3, MMP-1, MMP-13, thrombospondin motifs (ADAMTS-4) and ADAMTS-5 was also studied in primary cultured chondrocytes of rats. Naringenin caused significant reduction in pain behavior and showed marked improvement in the tissue morphology of MIA rats. Moreover, a significant inhibition of MMP-3 expression in MIA rats was observed upon treatment with naringenin. In the in vitro tests, naringenin caused a significant reduction in the transcriptional expression, secretion and enzymatic activity of the studied degradative enzymes. The NF-κB pathway was also found to be inhibited upon treatment with naringenin in vitro. Overall, the study suggests that naringenin alleviated pain and regulated the production of matrix-metalloproteinases via regulation of NF-κB pathway. Thus, naringenin could be a potent therapeutic option for the treatment of osteoarthritis.