Expression, purification and characterization of the IcmG and IcmK proteins of the type IVB secretion system from Coxiella burnetii.

Coxiella burnetii, the causative agent of Q fever, is an intracellular bacterial pathogen. Studies on Coxiella have shown that a type IVB secretion system (T4BSS) contributes to the establishment of the infection by transferring protein molecules. In this report, we focus on two core proteins of the Coxiella T4BSS, namely the IcmG/DotF protein (CBU_1626) and the IcmK/DotH protein (CBU_1628). Here we present a method for the recombinant expression of IcmG and IcmK in E. coli. IcmG was purified by Strep-Tactin affinity chromatography and size exclusion chromatography, while for the purification of IcmK an additional anion exchange chromatography step was introduced. The yields of the purified IcmG and IcmK proteins were 1.2 mg/L and 3 mg/L, respectively. The purified proteins showed predominant band on SDS-PAGE gel of 37 kDa for the IcmG and 40 kDa for the IcmK. Protein folding is confirmed by circular dichroism spectroscopy. The dynamic light scattering experiment indicated that IcmG and IcmK existed in a homogenous form. Further Blue native PAGE indicates the presences of a monomeric form for the IcmK and IcmG. Our work lays the basis for functional exploration and structural determination of IcmG and IcmK proteins of Coxiella's secretion system.

Proteome Changes Induced by Imatinib and Novel Imatinib Derivatives in K562 Human Chronic Myeloid Leukemia Cells.

Imatinib mesylate is the leading compound to treat chronic myeloid leukemia (CML) and other cancers, through its inhibition of Bcr-Abl tyrosine kinases. However, resistance to imatinib develops frequently, particularly in late-stage disease and has necessitated the development of new Bcr-Abl inhibitors. The synthesis of a new series of phenylaminopyrimidines, structurally related to imatinib, showed large interest since the introduction of nilotinib. Here, we compare the protein levels in K562 cells treated with either imatinib or with novel imatinib derivates. Our results revealed that among the 986 quantified proteins, 35 had significantly altered levels of expression by imatinib or its derivates. In a second series of experiments, we directly compared the proteomes of imatinib treated K562 cells with those K562 cells treated with any of the four imatinib derivates. More than 1029 protein were quantified, 80 of which had altered levels of expression. Both experiments pointed to changes in the expression of the ATP-dependent RNA helicase DDX3X and of two mitochondrial coiled-coil-helix-coiled-coil-helix domain-containing proteins.

Cognitive development of 12 month old Greek infants conceived after ICSI and the effects of the method on their parents.

BACKGROUND: ICSI is widely used as a method of assisted reproduction in Greece. Research shows that children conceived after the application of ICSI develop normally. However, Bowen et al. (1998) reported that children conceived after ICSI had lower scores in the Mental Development Index (MDI) of the Bayley Scales of Infant Development compared with infants conceived naturally or by standard IVF treatment. This finding raised concerns about the effects of ICSI on infants' cognitive development. The aim of the present study was twofold. First to compare the cognitive development of Greek infants conceived after ICSI treatment to a control group of infants conceived after IVF treatment and to a further control group conceived naturally (NC). Second, to investigate the psychological effects of ICSI compared to IVF on Greek parents. METHODS: The Bayley Scales of Infant Development were employed to assess cognitive development of infants. A 37 item semi-structured interview was devised to obtain demographic information and to assess and compare the psychological effects of ICSI and IVF on parents. RESULTS: The mental development of infants in all three groups was within the normal range (ICSI 101.4, IVF 95.7, NC 98.9). The differences between the three groups were not statistically significant. The duration of pregnancy and the birthweight differed in the three groups. Furthermore, mothers in the IVF and the ICSI groups experienced anxiety during pregnancy. IVF mothers differed in the mode of delivery and a smaller number of these mothers breastfed their infants. CONCLUSIONS: This study has shown that Greek infants, born after the application of ICSI, have mental and motor scores within the normal range. With regard to the psychological effects, it appears that mothers in the ICSI and IVF groups experience greater anxiety during their pregnancies than those in the NC group.