A rat oocyte differentiation antigen (OA-1) detected by a monoclonal antibody

Cell surface antigenic changes associated with differentiation of the rat oocyte and early embryo have been demonstrated with a monoclonal antibody (anti-OA-1). Antigen is first detectable coincident with initiation of oocyte growth, is a constant feature of all growing oocytes and displays a redistribution during meiotic maturation. Following fertilization, antigen is detectable on the surface of the embryo through the four-cell stage. This first monospecific marker for the rat oocyte and embryo should prove useful in probing structure/function relationships in oocyte growth, meiotic maturation fertilization, and/or early embryonic development.     

Thermostable and alkaline lipolytic and proteolytic enzymes produced by a thermophilic mold

The morphological, cultural and physiological characteristics of a thermophilic eumycete isolated from soil, showing strong lipase and protease activities, are described. The lipolytic and proteolytic crude enzyme preparations, recovered from submerged culture liquids, show considerable thermostability and optimum of activity at alkaline pH.     

Fishers' Knowledge Reveals Ecological Interactions Between Fish and Plants in High Diverse Tropical Rivers

Ecosystems - Frugivory and seed dispersal by fish is an important mutualistic interaction in complex and species-rich tropical rivers. The local ecological knowledge (LEK) held by fishers can...     

Molecular modelling of the photoconduction mechanism by charged solitons intrans-polyacetylene: I

It is possible to rationalize the different steps involved in the photoconductivity observed intrans-polyacetylene (t-PA) in terms of a simple chemical model. The interchain electron transfer (IET) and the intrachain polaron capture by neutral solitons proposed by Orensteinat al. may be represented within a simple molecular orbital (MO) picture. An efficiency index for the IET is proposed in terms of the binding energy of the charged polarons and of the electronic chemical potential. The predictive power of the efficiency index is analyzed in the context of the global softness concept. An MO protocol is described to obtain estimates of the IET hopping probabilities.     

Laser Speckle Imaging: A Novel Method for Detecting Dental Erosion

Erosion is a highly prevalent condition known as a non-carious lesion that causes progressive tooth wear due to chemical processes that do not involve the action of bacteria. Speckle images proved sensitive to even minimal mineral loss from the enamel. The aim of the present study was to investigate the use of laser speckle imaging analysis in the spatial domain to quantify shifts in the microstructure of the tooth surface in an erosion model. 32 fragments of the vestibular surface of bovine incisors were divided in for groups (10 min, 20 min. 30 min and 40 min of acid etching) immersed in a cola-based beverage (pH approximately 2.5) twice a day during 7 days to create an artificial erosion. By analyzing the laser speckle contrast map (LASCA) in the eroded region compared to the sound it was observed that the LASCA map shifts, proportionally to the acid each duration, by: 18%; 23%; 39% and 44% for the 10 min; 20 min; 30 min and 40 min groups, respectively. To the best of our knowledge, this is the first study to demonstrate the correlation between speckle patterns and erosion progression.     

Inhibition of protein kinase CK2 with the clinical-grade small ATP-competitive compound CX-4945 or by RNA interference unveils its role in acute myeloid leukemia cell survival,p53-dependent apoptosis and daunorubicin-induced cytotoxicity

Background

The involvement of protein kinase CK2 in sustaining cancer cell survival could have implications also in the resistance to conventional and unconventional therapies. Moreover, CK2 role in blood tumors is rapidly emerging and this kinase has been recognized as a potential therapeutic target. Phase I clinical trials with the oral small ATP-competitive CK2 inhibitor CX-4945 are currently ongoing in solid tumors and multiple myeloma.

Methods

We have analyzed the expression of CK2 in acute myeloid leukemia and its function in cell growth and in the response to the chemotherapeutic agent daunorubicin We employed acute myeloid leukemia cell lines and primary blasts from patients grouped according to the European LeukemiaNet risk classification. Cell survival, apoptosis and sensitivity to daunorubicin were assessed by different means. p53-dependent CK2-inhibition-induced apoptosis was investigated in p53 wild-type and mutant cells.

Results

CK2α was found highly expressed in the majority of samples across the different acute myeloid leukemia prognostic subgroups as compared to normal CD34⁺ hematopoietic and bone marrow cells. Inhibition of CK2 with CX-4945, K27 or siRNAs caused a p53-dependent acute myeloid leukemia cell apoptosis. CK2 inhibition was associated with a synergistic increase of the cytotoxic effects of daunorubicin. Baseline and daunorubicin-induced STAT3 activation was hampered upon CK2 blockade.

Conclusions

These results suggest that CK2 is over expressed across the different acute myeloid leukemia subsets and acts as an important regulator of acute myeloid leukemia cell survival. CK2 negative regulation of the protein levels of tumor suppressor p53 and activation of the STAT3 anti-apoptotic pathway might antagonize apoptosis and could be involved in acute myeloid leukemia cell resistance to daunorubicin.

     

Mixture models and wavelet transforms reveal high confidence RNA-protein interaction sites in MOV10 PAR-CLIP data

The Photo-Activatable Ribonucleoside-enhanced CrossLinking and ImmunoPrecipitation (PAR-CLIP) method was recently developed for global identification of RNAs interacting with proteins. The strength of this versatile method results from induction of specific T to C transitions at sites of interaction. However, current analytical tools do not distinguish between non-experimentally and experimentally induced transitions. Furthermore, geometric properties at potential binding sites are not taken into account. To surmount these shortcomings, we developed a two-step algorithm consisting of a non-parametric two-component mixture model and a wavelet-based peak calling procedure. Our algorithm can reduce the number of false positives up to 24% thereby identifying high confidence interaction sites. We successfully employed this approach in conjunction with a modified PAR-CLIP protocol to study the functional role of nuclear Moloney leukemia virus 10, a putative RNA helicase interacting with Argonaute2 and Polycomb. Our method, available as the R package wavClusteR, is generally applicable to any substitution-based inference problem in genomics.     

Expression of insulin‐like growth factor‐1 receptor in metastatic uveal melanoma and implications for potential autocrine and paracrine tumor cell growth

We investigated the importance of the insulin‐like growth factor‐1 receptor (IGF‐1R) in hepatic metastases of uveal melanoma. The expression pattern of IGF‐1R in archival tissue samples of hepatic metastasis from 24 patients was analyzed by immunohistochemistry. All the samples of hepatic metastases stained positive for IGF‐1R. To investigate the biological role of IGF‐1R on the growth of metastatic uveal melanoma, a long‐term cell line obtained from a hepatic metastasis (TJU‐UM001) was evaluated. TJU‐UM001 expressed cell surface IGF‐1R (>90%) and proliferated in response to exogenous and endogenous insulin‐like growth factor‐1 (IGF‐1). Correlatively, anti‐IGF‐1R antibody completely blocked IGF‐1‐induced growth of TJU‐UM001 cells. IGF‐1 preferentially induced phosphorylation of Akt (S473) in quiescent TJU‐UM001 cells, and this was blocked by anti‐IGF‐1R antibody. This study suggests that autocrine and paracrine mechanisms underlie IGF‐1‐induced growth of metastatic uveal melanoma and underscore the potential benefit of IGF‐1 or IGF‐1R antagonism in treatment for metastatic uveal melanoma.     

Vibrio cholerae persistence in aquatic environments and colonization of intestinal cells: involvement of a common adhesion mechanism

Forty-one Tnpho A mutants of Vibrio cholerae O1 classical strain CD81 were analyzed for their ability to interact with chitin particles, Tigriopus fulvus copepods and the Intestine 407 cell line compared to the parent strain. Thirteen mutants were less adhesive than CD81; in particular, T21, T33 and T87 were less adhesive towards all substrates and insensitive to inhibition by N-acetyl glucosamine (GlcNAc). By SDS-PAGE analysis of sarkosyl-insoluble membrane proteins (siMPs) isolated from mutants and parent, it was found that a 53 kDa siMP is missing in T21, T33 and T87 mutants. It is hypothesized that this protein might have the function to mediate adherence to GlcNAc-containing substrates both in the aquatic environment and in human intestine.