Long-term EGF/serum-treated human thyrocytes mimic papillary thyroid carcinomas with regard to gene expression

Constitutive activation of the RAS/RAF/MAPK pathway has been found in different tumor types including papillary thyroid carcinomas (PTCs). To get more insight into genes primarily regulated in the human tumor cells, an in vitro model was developed in which primary cultures of human thyrocytes were treated for different times with epidermal growth factor and serum (EGF/serum), which stimulate the MAPK cascade. Gene expression profiles were obtained by microarrays and compared to the expression profiles of PTCs. An evolution from short-term to long-term EGF/serum-treated cells was found, i.e., a program change showing a distinction between gene expression profiles of short-term and long-term EGF/serum-treated cells. The late pattern of EGF/serum stimulated cells converges to the pattern of PTCs. Comparison of these two types of cells with cAMP activated cells, from thyroid-stimulating hormone-treated thyrocytes and autonomous adenomas, showed distinct gene expression profiles for the two pathways. For the two models, an overlap was found in a number of genes which were early induced in vitro but down-regulated later in vitro and in the in vivo tumors. Thus, long-term stimulated human primary cultures demonstrate a clear relation with the tumor in vivo and could therefore be used as models for the disease.     

First evidences for a third sulfatase maturation system in prokaryotes from E. coli aslB and ydeM deletion mutants

To be active all known arylsulfatases undergo a unique post-translational modification leading to the conversion of an active site residue (serine or cysteine) into a C(alpha)-formylglycine. Although deprived of sulfatase activity, Escherichia coli K12 can efficiently mature heterologous Cys-type sulfatases. Three potential enzymes (AslB, YdeM and YidF) belonging to the anaerobic sulfatase maturating enzyme family (an SME) are present in its genome. Here we show that E. coli could mature Cys-type sulfatases only in aerobic conditions and that knocking-out of aslB, ydeM and yidF does not impair Cys-type sulfatase maturation. These findings demonstrate that these putative anSME are not involved in Cys-type sulfatase maturation and strongly support the existence of a second, oxygen-dependent and Cys-type specific sulfatase maturation system among prokaryotes.     

Studies of carotenoid one-electron reduction radicals

The relative reduction potentials of a variety of carotenoids have been established by monitoring the reaction of carotenoid radical anion (CAR1(*-)) with another carotenoid (CAR2) in hexane and benzene. This order is consistent with the reactivities of the carotenoid radical anions with porphyrins and oxygen in hexane. In addition, investigation of the reactions of carotenoids with reducing radicals in aqueous 2% Triton-X 100, such as carbon dioxide radical anion (CO2(*-)), acetone ketyl radical (AC(*-)) and the corresponding neutral radical (ACH(*)), reveals that the reduction potentials for beta-carotene and zeaxanthin lie in the range -1950 to -2100 mV and those for astaxanthin, canthaxanthin and beta-apo-8'-carotenal are more positive than -1450 mV. This illustrates that the presence of a carbonyl group causes the reducing ability to decrease. The radical cations have been previously shown to be strong oxidising agents and we now show that the radical anions are very strong reducing agents.     

Itch inhibition regulates chemosensitivity in vitro

Itch is a member of the HECT family of ubiquitin E3 ligases, and regulates the stability of several proteins involved in response to genotoxic stress. We have previously shown that p73 and p63, two members of the p53 family of tumour suppressors, are targets for Itch-mediated ubiquitylation and degradation. Here, we show that depletion of Itch by RNA interference augments apoptosis upon treatment with chemotherapeutic drugs. We also show that cells with no functional p53 are more sensitive to Itch depletion, highlighting the importance that changes in levels of Itch may play in majority of cancers, where p53 is absent or mutated. Furthermore, reintroduction of Itch in fibroblasts obtained from Itch deficient mice results in reduced cell death upon DNA damage. Overall our findings suggest that inhibition of Itch potentiates the effect of chemotherapeutic drugs revealing the pharmacological potentials of targeting Itch for cancer therapy.     

Identification of a ubiG-like gene involved in ubiquinone biosynthesis from Chlamydophila pneumoniae AR39

AIMS: To investigate if one hypothetical protein from Chlamydophila pneumoniae AR39 exerts UbiG-like function by complementary experiments. METHODS AND RESULTS: Proteins UbiG have a signature S-adenosylmethionine-binding motif compared with other methyltransferases. Probing with the conserved motif, one hypothetical protein from C. pneumoniae AR39 was proposed to be a UbiG-like protein. The protein encoding the gene was used to swap its counterpart in Escherichia coli, and its expression in resultant strain DYCG was confirmed by RT-PCR. Strain DYCG grew on succinate as a carbon source, and rescued ubiquinone content in vivo, while the ubiG deletion strain DYK did not. CONCLUSIONS: Results indicate that the putative protein from C. pneumoniae exerts a UbiG-like function involved in ubiquinone biosynthesis. SIGNIFICANCE AND IMPACT OF THE STUDY: Identification of the ubiG-like gene will facilitate research on ubiquinone biosynthesis and aerobic respiration in the genus Chlamydophila owing to the important function of ubiquinone in vivo.     

Organ identity of the thalloid plant body of Griffithella hookeriana and Polypleurum stylosum – Podostemoideae (Podostemaceae)

The morphological nature of the thalloid plant body of podostemads has remained controversial for long. The present investigation was carried out on two members of the Podostemoideae i.e. Griffithella hookeriana and Polypleurum stylosum to understand their organ identity. The origin of the plant body was traced from the embryo by germinating the seeds under aseptic conditions. Mature embryo of both species does not show an identifiable shoot apical meristem (SAM) and root apical meristem (RAM). Upon germination, the radicular pole does not form a primary root but differentiates adhesive hairs. At the cotyledonary junction, SAM is initiated that differentiates 6–9 leaves apically (primary axis) and a primordium laterally. This primordium subsequently emerges from the hypocotyl and develops into a thalloid plant. The latter has been interpreted as a flattened stem because it not only shows tunica-corpus like organization at the tip but also originates endogenously from the same SAM that forms the `primary axis'.     

Synthesis,Antioxidant Activity and Cytotoxicity of N-Functionalized Organotellurides

The use of antioxidants is the most effective means to protect the organism against cellular damage caused by oxidative stress. In this context, organotellurides have been described as promising antioxidant agents for decades. Herein, a series of N-functionalized organotellurium compounds has been tested as antioxidant and presented remarkable activities by three different in vitro chemical assays. They were able to reduce DPPH radical with IC₅₀ values ranging from 5.08 to 19.20?µg?mL^?1, and some of them also reduced ABTS⁺ radical and TPTZ-Fe³⁺ complex in ABTS⁺ and FRAP assays, respectively. Initial structure-activity relationship discloses that the nature of N-substituent strongly influenced both activity and cytotoxicity of the studied compounds. Furthermore, radical scavenging activities of N-functionalized organotellurides have been compared with those of their selenilated congeners, demonstrating that the presence of tellurium atom has an essential role in antioxidant activity.