Cells from patients with Fanconi anemia (FA), an inherited disorder that includes bone marrow failure and cancer predisposition, have increased sensitivity to oxidative stress through an unknown mechanism. We demonstrate that the FA group G (FANCG) protein is found in mitochondria. Wild-type but not G546R mutant FANCG physically interacts with the mitochondrial peroxidase peroxiredoxin-3 (PRDX3). PRDX3 is deregulated in FA cells, including cleavage by a calpainlike cysteine protease and mislocalization. FA-G cells demonstrate distorted mitochondrial structures, and mitochondrial extracts have a sevenfold decrease in thioredoxin-dependent peroxidase activity. Transient overexpression of PRDX3 suppresses the sensitivity of FA-G cells to H2O2, and decreased PRDX3 expression increases sensitivity to mitomycin C. Cells from the FA-A and -C subtypes also have PRDX3 cleavage and decreased peroxidase activity. This study demonstrates a role for the FA proteins in mitochondria witsh sensitivity to oxidative stress resulting from diminished peroxidase activity. These defects may lead to apoptosis and the accumulation of oxidative DNA damage in bone marrow precursors.

The removal of DNA interstrand cross-links (ICLs) has proven to be notoriously complicated due to the involvement of multiple pathways of DNA repair, which include the Fanconi anemia/BRCA pathway, homologous recombination and components of the nucleotide excision and mismatch repair pathways. Members of the SNM1 gene family have also been shown to have a role in mediating cellular resistance to ICLs, although their precise function has remained elusive. Here, we show that knockdown of Snm1B/Apollo in human cells results in hypersensitivity to mitomycin C (MMC), but not to IR. We also show that Snm1B-deficient cells exhibit a defective S phase checkpoint in response to MMC, but not to IR, and this finding may account for the specific sensitivity to the cross-linking drug. Interestingly, although previous studies have largely implicated ATR as the major kinase activated in response to ICLs, we show that it is activation of the ATMmediated checkpoint that is defective in Snm1B-deficient cells. The requirement for Snm1B in ATM checkpoint activation specifically after ICL damage is correlated with its role in promoting double-strand break formation, and thus replication fork collapse. Consistent with this result Snm1B was found to interact directly with Mus81-Eme1, an endonuclease previously implicated in fork collapse. In addition, we also show that Snm1B interacts with the Mre11-Rad50-Nbs1 (MRN) complex and with FancD2 further substantiating its role as a checkpoint/DNA repair protein.

Development of suitable materials that acts as an interface between the implant and tissues in body system structurally, mechanically and bio functionally is important for the success of tissue engineering. This motivated materials scientists and biologists to find out suitable bioactive materials for the aforementioned purpose. There has been growing interest in developing bioactive synthetic ceramics that could closely mimic natural apatite characteristics. Hydroxyapatite (HAp) has been widely used as a biocompatible ceramic but mainly for contact with bone tissue, due to its resemblance to mineral bone. This study presents the synthesis and characterization of HAp materials from different sources like bovine bone and fish scales and their application in tissue engineering. The phase purity and crystallinity of different calcined HAp powder was determined by XRD and FTIR analysis. The Thermo Gravimetric and Differential Thermal Analysis were carried out to show the thermal stability of the HAp powder. The morphology of the powder was observed under Scanning Electron Microscopy (SEM). Cytotoxicity evaluation of the developed powder was carried out in RAW macrophage like cell line media for an incubation period of 72 hours. These results proved the biocompatibility of HAp powders obtained from different biosources for tissue engineering applications.

The distal region (؊830 to ؊720 bp) of the rat whey acidic protein (WAP) gene contains a composite response element (CoRE), which has been demonstrated previously to confer mammary gland-specific and hormonally regulated WAP gene expression. Point mutations in the binding sites for specific transcription factors present within this CoRE have demonstrated the importance of both nuclear factor I (NFI) and STAT5 as well as cooperative interactions with the glucocorticoid receptor (GR) in the regulation of WAP gene expression in the mammary gland of transgenic mice. This study reports the characterization of NFI gene expression during mammary gland development and the identification and cloning of specific NFI isoforms (NFI-A4, NFI-B2, and NFI-X1) from the mouse mammary gland during lactation. Some but not all of these NFI isoforms synergistically activate WAP gene transcription in cooperation with GR and STAT5, as determined using transient cotransfection assays in JEG-3 cells. On both the WAP CoRE and the mouse mammary tumor virus long terminal repeat promoter, the NFI-B isoform preferentially activated gene transcription in cooperation with STAT5A and GR. In contrast, the NFI-A isoform suppressed GR and STAT cooperativity at the WAP CoRE. Finally, unlike their interaction with the NFI consensus binding site in the adenovirus promoter, the DNA-binding specificities of the three NFI isoforms to the palindromic NFI site in the WAP CoRE were not identical, which may partially explain the failure of the NFI-A isoform to cooperate with GR and STAT5A.

In the present study, hydroxyapatite (HAp) is synthesized from different biosources like eggshell, fish scale and bovine bone in a cost effective and ecofriendly way. HAp materials were synthesized from eggshell by wet precipitation method whereas thermal decomposition method was applied in case of fish scale and bovine bone. The phase purity and crystallinity of different calcined HAp powder were determined by XRD and FTIR analyses. The thermogravimetric analysis was carried out to show thermal stability of HAp powder. Average grain sizes of sintered samples were in submicron range. The morphology of the powders were observed under scanning electron microscopy (SEM). The dried powders were wet ball milled for several hours and surfactants like Triton-X small fillers (2 / 4 mm long rod-shaped) were made for in vitro testing. In order to verify the biocompatibility of HAp powders, cytotoxicity evaluation was carried out in RAW macrophage like cell line media for an incubation period of 72 h. The cell attachment studies on HAp compacts show an excellent affinity between cells and compact surface. These results proved high biocompatibility of HAp powders obtained from different biosources for tissue engineering applications.

The chemically treated Labeo rohita scale is used for synthesizing hydroxyapatite (HAp) biomaterials. Thermogravimetric and differential thermal analyses of fish scale materials reveal the different phase changes with temperature and find out the suitable calcination temperatures. The composition and structures of wet ball-milled calcined HAp powders are characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis (EDX). The EDX as well as chemical analysis of fish scale-derived apatite materials confirms that the Ca/P ratio is 1.71. The compressive stress, hardness and porosity have been evaluated on sintered HAp biomaterials. The cell attachment on HAp surfaces, cytotoxicity evaluation and MTT assay, which are carried out in RAW macrophage-like cell line media demonstrate good biocompatibility. The histological analysis also supports the bioaffinity of processed HAp biomaterials in Wistar rat model for investigating the contact reaction and stability at the artificial or natural prosthesis interface.

Previously, we have shown that SNM1A is a multifunctional gene involved in both the DNA damage response and in an early mitotic checkpoint in response to spindle stress. Another member of the SNM1 gene family, SNM1B/Apollo, has been shown to have roles in both the response to DNA interstrand cross-linking agents and in telomere protection during S phase. Here, we demonstrate a novel role for SNM1B/Apollo in mitosis in response to spindle stress. SNM1B-deficient cells exhibit a defect in the prophase checkpoint. Loss of the prophase checkpoint induces an extended mitotic delay, which is due to prolonged activation of the spindle checkpoint. In addition, we show that SNM1B/Apollo interacts with the essential microtubule binding protein Astrin. SNM1B/ Apollo interacts with Astrin through its conserved metallo-β-lactamase domain, and disruption of this interaction by point mutations results in a deficient prophase checkpoint. These findings suggest that SNM1B/Apollo and Astrin function together to enforce the prophase checkpoint in response to spindle stress.

Kinetics of the interaction between [Pt(pic)(H2O)2](ClO4)2and selected thiols has been studied in aqueous medium as a function of [complex], [thiol], pH and temperature at constant ionic strength.