Silicon induces phytochelatin and ROS scavengers facilitating cadmium detoxification in rice

• Cadmium (Cd) is detrimental to crops and the environment. This work examines the natural mechanisms underlying silicon‐ (Si‐)directed Cd detoxification in rice plants.
• The addition of Si to plants under Cd stress caused significant improvements in morphological parameters, chlorophyll score, F_v/F_m and total soluble protein concentration compared to controls, confirming that Si is able to ameliorate Cd‐induced damage in rice plants. This morpho‐physiological evidence was correlated with decreased cell death and electrolyte leakage after Si application.
• The results showed no critical changes in root Cd concentration, while shoot Cd decreased significantly after Si supplementation in comparison with Cd‐stressed rice. Additionally, expression of Cd transporters (OsNRAMP5 and OsHMA2) was significantly down‐regulated while the concentration of phytochelatin, cysteine and glutathione, together with expression of OsPCS1 (phytochelatin synthase) in roots of Cd‐stressed rice was significantly induced when subjected to Si treatment. This confirms that the alleviation of Cd stress is not only limited to the down‐regulation of Cd transporters but also closely related to the phytochelatin‐driven vacuolar storage of Cd in rice roots.
• The enzymatic analysis further revealed the role of SOD and GR enzymes in protecting rice plants from Cd‐induced oxidative harm. These findings suggest a mechanistic basis in rice plants for Si‐mediated mitigation of Cd stress.

     

Spatial autocorrelation in two Iris pumila populations estimated on morphological data from natural clones and their samples grown in two different habitats

Morphological data from two Iris pumila populations (measured on native clones, on their replants into the same habitat, and on their transplants into alternative habitat) were combined with native clones spatial position and spatial autocorrelations (SA) were calculated. Naturally growing I. pumila clones revealed significant SA that were positive on small distances and negative on medium ones in both open Hillock and shaded Woodland populations. No significant SA were detected when calculated with original clone positions, but with morphometric data from replants into the experimental plot in the same habitat. Some significant SA were, however, detected when morphometric data from transplants to alternative habitat were used. Detected SA on I. pumila clones were primarily a consequence of spatial structuring of environmental factors but also, in a lesser degree, a result of genetic spatial arrangements (most probably due to patterns of gene flow). The text was submitted by the authors in English.     

Elevated Soluble CD163 in Gestational Diabetes Mellitus: Secretion from Human Placenta and Adipose Tissue

Recently soluble CD163 (sCD163), a cleaved form of the macrophage receptor CD163, was identified as a macrophage-specific risk-predictor for developing Type 2 Diabetes. Here, we investigate circulating levels of sCD163 in gestational diabetes mellitus (GDM). Furthermore, given the role of the placenta in the pathogenesis of GDM, we assessed placental contribution to sCD163 secretion. Paired maternal (venous) and umbilical vein blood samples from GDM (n = 18) and Body Mass Index (BMI) matched control women (n = 20) delivered by caesarean section at 39–40 week gestation were assessed for circulating levels of sCD163, Tumour necrosis factor alpha (TNF-α) and Interleukin 6 (IL-6). Media from explant culture of maternal subcutaneous fat and corresponding placental tissues were assayed for these same molecules. CD163 positive cell numbers were determined in placental and adipose tissues of GDM and control women. We found significantly elevated circulating sCD163 levels in GDM mothers (688.4±46.9 ng/ml vs. 505.6±38.6 ng/ml) and their offspring (418.2±26.6 ng/ml vs. 336.3±24.4 ng/ml [p<0.05 for both]) as compared to controls, together with elevated circulating TNF-α and IL-6 levels. Moreover, both GDM placentae (268.1±10.8 ng/ml/mg vs. 187.6±20.6 ng/ml/mg) and adipose explants (41.1±2.7 ng/ml/mg vs. 26.6±2.4 ng/ml/mg) released significantly more sCD163 than controls. Lastly, significantly more CD163 positive cells were observed in GDM placentae (25.7±1.1 vs. 22.1±1.2) and adipose tissue (19.1±1.1 vs 12.7±0.9) compared to controls. We describe elevated sCD163 levels in GDM and identify human placenta as a novel source of sCD163 suggesting that placental tissues might contribute to the increased levels of circulating sCD163 in GDM pregnancies.     

Biotransformation of tea catechins into theaflavins with immobilized polyphenol oxidase

Theaflavins, an active antioxidant, a natural pigment and pharmacologically active molecule obtained from black tea were bioprocessed on an immobilized tea polyphenol oxidase (PPO) system by the conversion of tea catechins extracted from green tea leaves with an overall conversion efficiency of 85% about 14-fold increase over maximum achievable in normal black teas. The immobilized enzyme (IE) system consists of activated cellulose matrix on to which the freshly extracted tea leaf polyphenol oxidase was covalently linked. Cellulose as a matrix of choice was considered primarily for its non-toxic nature, natural origin, low cost and easy availability. The kinetic parameters of the IE system were; protein loading capacity 11.8 mg/g; pH optimum 5.9; temperature optimum 37.5 °C; K_m 4.76 ± 0.08 mM; V_max 20 ± 1.80 nmol/min; enzyme activity retention (83.58%) and number of batches per turnover without loss of activity was 14. The product from IE system was identified by HPLC and ESI-QTOF-MS spectrometry.     

Effect of T3 on metabolic response and oxidative stress in skeletal muscle from sedentary and trained rats

We investigated whether swim training modifies the effect of T₃-induced hyperthyroidism on metabolism and oxidative damage in rat muscle. Respiratory capacities, oxidative damage, levels of antioxidants, and susceptibility to oxidative challenge of homogenates were determined. Mitochondrial respiratory capacities, H₂O₂ release rates, and oxidative damage were also evaluated. T₃-treated rats exhibited increases in muscle respiratory capacity, which were associated with enhancements in mitochondrial respiratory capacity and tissue mitochondrial protein content in sedentary and trained animals, respectively. Hormonal treatment induced muscle oxidative damage and GSH depletion. Both effects were reduced by training, which also attenuated tissue susceptibility to oxidative challenge. The changes in single antioxidant levels were slightly related to oxidative damage extent, but the examination of parameters affecting the susceptibility to oxidants indicated that training was associated with greater effectiveness of the muscle antioxidant system. Training also attenuated T₃-induced increases in H₂O₂ production and, therefore, oxidative damage of mitochondria by lowering their content of autoxidizable electron carriers. The above results suggest that moderate training is able to reduce hyperthyroid state-linked tissue oxidative damage, increasing antioxidant protection and decreasing the ROS flow from the mitochondria to the cytoplasmic compartment.     

Phylogenetic analysis of the tenascin gene family: evidence of origin early in the chordate lineage

Background  

Tenascins are a family of glycoproteins found primarily in the extracellular matrix of embryos where they help to regulate cell proliferation, adhesion and migration. In order to learn more about their origins and relationships to each other, as well as to clarify the nomenclature used to describe them, the tenascin genes of the urochordate Ciona intestinalis, the pufferfish Tetraodon nigroviridis and Takifugu rubripes and the frog Xenopus tropicalis were identified and their gene organization and predicted protein products compared with the previously characterized tenascins of amniotes.