Trehalose determination in linseed subjected to osmotic stress. HPAEC‐PAD analysis: an inappropriate method

Trehalose is a non‐reducing disaccharide involved in stress tolerance in plants. To understand better the role of trehalose in the osmotic stress response in linseed (Linum usitatissimum), trehalose content in leaves was studied. First, the method commonly used for sugar determination, high performance anion exchange chromatography with pulsed amperometric detection (HPAEC‐PAD), gave unsatisfactory results and the separation efficiency could not be improved by varying the elution conditions. The same problem was also found in the model plant: Arabidopsis thaliana. After clearly highlighting a co‐elution of trehalose in these two species by a trehalase assay and liquid chromatography‐high resolution mass spectrometry analysis, gas chromatography–mass spectrometry (GC‐MS) was used as the analytical method instead. These results confirmed that trehalose content is currently overestimated by HPAEC‐PAD analysis, approximately 7 and 13 times for A. thaliana and linseed respectively. Thus GC‐MS gave more satisfactory results for trehalose quantification in plants. With this method, trehalose accumulation was observed in linseed during an osmotic stress (?0.30 MPa), the quantity (31.49 nmol g^–1 dry weight after 48 h) appears too low to assign an osmoprotector or osmoregulator role to trehalose in stressed linseed.     

Mechanisms of radioresistance and the underlying signaling pathways in colorectal cancer cells

Radiotherapy is one of the most common modalities for the treatment of a wide range of tumors, including colorectal cancer (CRC); however, radioresistance of cancer cells remains a major limitation for this treatment. Following radiotherapy, the activities of various cellular mechanisms and cell signaling pathways are altered, resulting in the development of radioresistance, which leads to therapeutic failure and poor prognosis in patients with cancer. Furthermore, even though several inhibitors have been developed to target tumor resistance, these molecules can induce side effects in nontumor cells due to low specificity and efficiency. However, the role of these mechanisms in CRC has not been extensively studied. This review discusses recent studies regarding the relationship between radioresistance and the alterations in a series of cellular mechanisms and cell signaling pathways that lead to therapeutic failure and tumor recurrence. Our review also presents recent advances in the in vitro/in vivo study models aimed at investigating the radioresistance mechanism in CRC. Furthermore, it provides a relevant biochemical basis in theory, which can be useful to improve radiotherapy sensitivity and prolong patient survival.     

Silver-Zeolite Combined to Polyphenol-Rich Extracts of Ascophyllum nodosum: Potential Active Role in Prevention of Periodontal Diseases

The purpose of this study was to evaluate various biological effects of silver-zeolite and a polyphenol-rich extract of A. nodosum (ASCOP) to prevent and/or treat biofilm-related oral diseases. Porphyromonas gingivalis and Streptococcus gordonii contribute to the biofilm formation associated with chronic periodontitis. In this study, we evaluated in vitro antibacterial and anti-biofilm effects of silver-zeolite (Ag-zeolite) combined to ASCOP on P. gingivalis and S. gordonii growth and biofilm formation capacity. We also studied the anti-inflammatory and antioxidant capacities of ASCOP in cell culture models. While Ag-zeolite combined with ASCOP was ineffective against the growth of S. gordonii, it showed a strong bactericidal effect on P. gingivalis growth. Ag-zeolite combined with ASCOP was able to completely inhibit S. gordonii monospecies biofilm formation as well as to reduce the formation of a bi-species S. gordonii/P. gingivalis biofilm. ASCOP alone was ineffective towards the growth and/or biofilm formation of S. gordonii and P. gingivalis while it significantly reduced the secretion of inflammatory cytokines (TNFα and IL-6) by LPS-stimulated human like-macrophages. It also exhibited antioxidant properties and decreased LPS induced lipid peroxidation in gingival epithelial cells. These findings support promising use of these products in future preventive or therapeutic strategies against periodontal diseases.     

Localization of the rat immunoglobulin lambda light chain locus to chromosome 11

Previous experiments using rat/mouse somatic cell hybrids have localized the rat c-myc gene to chromosome 7 (Sümegi et al. 1983), the rat immunoglobulin kappa locus to chromosome 4 (Perlmann et al. 1985), and the rat immunoglobulin heavy chain locus to chromosome 6 (Pear et al. 1986). Using a similar approach, we now report the localization of the rat immunoglobulin lambda light chain locus to chromosome 11.