Adaptation of plants to high-calcium content kart regions: possible involvement of symbiotic microorganisms and underlying mechanisms / Adaptação de plantas a regiões de kart com alto teor de cálcio: possível envolvimento de microrganismos simbióticos e mecanismos subjacentes

Abstract Rhizosphere microorganisms and endophytes can help their hosts absorb nutrients and regulate the levels of plant hormones. Moreover, they can modulate the expressions of host genes, assist hosts in eliminating reactive oxygen species (ROS) and secreting volatile organic compounds. Therefore, rhizosphere microorganisms and endophytes are considered as determinant factors driving processes involved in the growth of host plants. However, the physiological and ecological functions, as well as the molecular mechanism underlying the behavior of rhizosphere microorganisms and endophytes in their role in the adaptive capacity of host plants in the karstic high-calcium environment have not been systematically studied. This review summarizes the physiological and molecular mechanisms of rhizosphere microorganisms and endophytes which help host plants to adapt to various kinds of adverse environments. The adaptive capacities of plants growing in adverse environments, partly, or totally, depends on microorganisms co-existing with the host plants.

Resumo Os microorganismos e endófitos da rizosfera podem ajudar seus hospedeiros a absorver nutrientes e regular os níveis de hormônios vegetais. Além disso, eles podem modular as expressões dos genes hospedeiros, auxiliar os hospedeiros na eliminação de espécies reativas de oxigênio (ROS) e secretar compostos orgânicos voláteis. Portanto, microorganismos e endófitos da rizosfera são considerados determinantes dos processos envolvidos no crescimento de plantas hospedeiras. No entanto, as funções fisiológicas e ecológicas, bem como o mecanismo molecular subjacente ao comportamento dos microrganismos e endofíticos da rizosfera no seu papel na capacidade adaptativa das plantas hospedeiras no ambiente cárstico de alto teor de cálcio, não foram sistematicamente estudados. Esta revisão resume os mecanismos fisiológicos e moleculares de microrganismos e endófitos da rizosfera que ajudam as plantas hospedeiras a se adaptarem a vários tipos de ambientes adversos. As capacidades adaptativas das plantas que crescem em ambientes adversos, em parte ou totalmente, dependem de microrganismos coexistentes com as plantas hospedeiras.

Association of furanone C-30 with biofilm formation & antibiotic resistance in Pseudomonas aeruginosa

Background & objectives: Pseudomonas aeruginosa is an opportunistic pathogen that can cause nosocomial bloodstream infections in humans. This study was aimed to explore the association of furanone C-30 with biofilm formation, quorum sensing (QS) system and antibiotic resistance in P. aeruginosa. Methods: An in vitro model of P. aeruginosa bacterial biofilm was established using the standard P. aeruginosa strain (PAO-1). After treatment with 2.5 and 5 ?g/ml of furanone C-30, the change of biofilm morphology of PAO-1 was observed, and the expression levels of QS-regulated virulence genes (lasB, rhlA and phzA2), QS receptor genes (lasR, rhlR and pqsR) as well as QS signal molecule synthase genes (lasI, rhlI, pqsE and pqsH) were determined. Besides, the AmpC expression was quantified in planktonic and mature biofilm induced by antibiotics. Results: Furanone C-30 treatment significantly inhibited biofilm formation in a dose-dependent manner. With the increase of furanone C-30 concentration, the expression levels of lasB, rhlA, phzA2, pqsR, lasI, rhlI pqsE and pqsH significantly decreased in mature biofilm bacteria while the expression levels of lasR and rhlR markedly increased. The AmpC expression was significantly decreased in both planktonic and biofilm bacteria induced by imipenem and ceftazidime. Interpretation & conclusions: Furanone C-30 may inhibit biofilm formation and antibiotic resistance in P. aeruginosa through regulating QS genes. The inhibitory effect of furanone C-30 on las system appeared to be stronger than that on rhl system. Further studies need to be done with different strains of P. aeruginosa to confirm our findings.

Adaptation of plants to high-calcium content kart regions: possible involvement of symbiotic microorganisms and underlying mechanisms

Abstract Rhizosphere microorganisms and endophytes can help their hosts absorb nutrients and regulate the levels of plant hormones. Moreover, they can modulate the expressions of host genes, assist hosts in eliminating reactive oxygen species (ROS) and secreting volatile organic compounds. Therefore, rhizosphere microorganisms and endophytes are considered as determinant factors driving processes involved in the growth of host plants. However, the physiological and ecological functions, as well as the molecular mechanism underlying the behavior of rhizosphere microorganisms and endophytes in their role in the adaptive capacity of host plants in the karstic high-calcium environment have not been systematically studied. This review summarizes the physiological and molecular mechanisms of rhizosphere microorganisms and endophytes which help host plants to adapt to various kinds of adverse environments. The adaptive capacities of plants growing in adverse environments, partly, or totally, depends on microorganisms co-existing with the host plants.

Resumo Os microorganismos e endófitos da rizosfera podem ajudar seus hospedeiros a absorver nutrientes e regular os níveis de hormônios vegetais. Além disso, eles podem modular as expressões dos genes hospedeiros, auxiliar os hospedeiros na eliminação de espécies reativas de oxigênio (ROS) e secretar compostos orgânicos voláteis. Portanto, microorganismos e endófitos da rizosfera são considerados determinantes dos processos envolvidos no crescimento de plantas hospedeiras. No entanto, as funções fisiológicas e ecológicas, bem como o mecanismo molecular subjacente ao comportamento dos microrganismos e endofíticos da rizosfera no seu papel na capacidade adaptativa das plantas hospedeiras no ambiente cárstico de alto teor de cálcio, não foram sistematicamente estudados. Esta revisão resume os mecanismos fisiológicos e moleculares de microrganismos e endófitos da rizosfera que ajudam as plantas hospedeiras a se adaptarem a vários tipos de ambientes adversos. As capacidades adaptativas das plantas que crescem em ambientes adversos, em parte ou totalmente, dependem de microrganismos coexistentes com as plantas hospedeiras.

Delivery of the Sox9 gene promotes chondrogenic differentiation of human umbilical cord blood-derived mesenchymal stem cells in an in vitro model

SRY-related high-mobility-group box 9 (Sox9) gene is a cartilage-specific transcription factor that plays essential roles in chondrocyte differentiation and cartilage formation. The aim of this study was to investigate the feasibility of genetic delivery of Sox9 to enhance chondrogenic differentiation of human umbilical cord blood-derived mesenchymal stem cells (hUC-MSCs). After they were isolated from human umbilical cord blood within 24 h after delivery of neonates, hUC-MSCs were untreated or transfected with a human Sox9-expressing plasmid or an empty vector. The cells were assessed for morphology and chondrogenic differentiation. The isolated cells with a fibroblast-like morphology in monolayer culture were positive for the MSC markers CD44, CD105, CD73, and CD90, but negative for the differentiation markers CD34, CD45, CD19, CD14, or major histocompatibility complex class II. Sox9 overexpression induced accumulation of sulfated proteoglycans, without altering the cellular morphology. Immunocytochemistry demonstrated that genetic delivery of Sox9 markedly enhanced the expression of aggrecan and type II collagen in hUC-MSCs compared with empty vector-transfected counterparts. Reverse transcription-polymerase chain reaction analysis further confirmed the elevation of aggrecan and type II collagen at the mRNA level in Sox9-transfected cells. Taken together, short-term Sox9 overexpression facilitates chondrogenesis of hUC-MSCs and may thus have potential implications in cartilage tissue engineering.

Quercetin postconditioning attenuates myocardial ischemia/reperfusion injury in rats through the PI3K/Akt pathway

Quercetin (Que), a plant-derived flavonoid, has multiple benefical actions on the cardiovascular system. The current study investigated whether Que postconditioning has any protective effects on myocardial ischemia/reperfusion (I/R) injury in vivo and its potential cardioprotective mechanisms. Male Sprague-Dawley rats were randomly allocated to 5 groups (20 animals/group): sham, I/R, Que postconditioning, Que+LY294002 [a phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway inhibitor], and LY294002+I/R. I/R was produced by 30-min coronary occlusion followed by 2-h reperfusion. At the end of reperfusion, myocardial infarct size and biochemical changes were compared. Apoptosis was evaluated by both TUNEL staining and measurement of activated caspase-3 immunoreactivity. The phosphorylation of Akt and protein expression of Bcl-2 and Bax were determined by Western blotting. Que postconditioning significantly reduced infarct size and serum levels of creatine kinase and lactate dehydrogenase compared with the I/R group (all P<0.05). Apoptotic cardiomyocytes and caspase-3 immunoreactivity were also suppressed in the Que postconditioning group compared with the I/R group (both P<0.05). Akt phosphorylation and Bcl-2 expression increased after Que postconditioning, but Bax expression decreased. These effects were inhibited by LY294002. The data indicate that Que postconditioning can induce cardioprotection by activating the PI3K/Akt signaling pathway and modulating the expression of Bcl-2 and Bax proteins.

The efficacy of YKL-40 and CA125 as biomarkers for epithelial ovarian cancer

Our objective was to estimate the efficacy of the measurement of serum YKL-40 alone or with CA125 as biomarkers for the diagnosis of epithelial ovarian cancer (EOC) using the YKL-40 ELISA kit. An experimental group of 49 ovarian cancer patients included 42 patients with EOC (53 ± 15 years, range: 19-81 years) and 7 patients (48 ± 13 years, range: 29-36 years) with borderline epithelial ovarian tumor. A control group of 88 non-malignant cases included 42 patients (43 ± 10 years, range: 26-77 years) with benign gynecological disease and 46 healthy women (45 ± 14 years, range: 30-68 years) at a teaching hospital. Both YKL-40 (220.1 ± 94.1 vs 61.6 ± 48.4 and 50.1 ± 41.2 ng/mL) and CA125 (524.9 ± 972.5 vs 13.4 ± 7.6 and 28.5 ± 29.6 U/mL) levels were significantly higher (P < 0.05) in patients with ovarian cancer compared to the healthy and non-malignant groups. YKL-40 had 92.9 percent sensitivity and 94.4 percent specificity for the diagnosis of EOC. When YKL-40 and CA125 were tested in parallel, the sensitivity was increased to 98.2 percent, but the specificity was decreased to 81.3 percent. The correlations between serum YKL-40 and tumor stage, grade histology, performance status, patient age, and extension of debulking surgery were tested. With increasing stage and grade of EOC, preoperative serum YKL-40 levels were significantly increased (P = 0.029, P = 0.05, respectively). Serum YKL-40 alone or with serum CA125 levels are useful, although with some limitations, to diagnose ovarian cancer. Our study showed that YKL-40 may not be an independent prognostic factor for ovarian cancer. This prospective study may be a new trend in looking for biomarkers that optimize diagnosis of ovarian cancer.

Role of nuclear factor kappa B and reactive oxygen species in the tumor necrosis factor-a-induced epithelial-mesenchymal transition of MCF-7 cells

The microenvironment of the tumor plays an important role in facilitating cancer progression and activating dormant cancer cells. Most tumors are infiltrated with inflammatory cells which secrete cytokines such as tumor necrosis factor-alpha (TNF-alpha). To evaluate the role of TNF-alpha in the development of cancer we studied its effects on cell migration with a migration assay. The migrating cell number in TNF-alpha-treated group is about 2-fold of that of the control group. Accordingly, the expression of E-cadherin was decreased and the expression of vimentin was increased upon TNF-alpha treatment. These results showed that TNF-alpha can promote epithelial-mesenchymal transition (EMT) of MCF-7 cells. Further, we found that the expression of Snail, an important transcription factor in EMT, was increased in this process, which is inhibited by the nuclear factor kappa B (NFkB) inhibitor aspirin while not affected by the reactive oxygen species (ROS) scavenger N-acetyl cysteine. Consistently, specific inhibition of NFkB by the mutant IkBalpha also blocked the TNF-alpha-induced upregulation of Snail promoter activity. Thus, the activation of NFkB, which causes an increase in the expression of the transcription factor Snail is essential in the TNF-alpha-induced EMT. ROS caused by TNF-alpha seemed to play a minor role in the TNF-alpha-induced EMT of MCF-7 cells, though ROS per se can promote EMT. These findings suggest that different mechanisms might be responsible for TNF-alpha - and ROS-induced EMT, indicating the need for different strategies for the prevention of tumor metastasis induced by different stimuli.