Chromosome-specific subsets of human alphoid DNA identified by a chromosome 2-derived clone

We have cloned an alphoid DNA fragment, pBS4D, from the DNA of a human-hamster hybrid cell line containing chromosome 2 as its only cytologically detectable human component. Under high stringency conditions, pBS4D hybridized in situ mostly to chromosome 2 and to a lesser extent to chromosomes 18 and 20. Restriction analysis using the DNA from selected somatic hybrid cell lines revealed that the genomic organization of this alphoid DNA differs on each of these three chromosomes.     

Growth factors in breast cancer: mitogenesis to transformation.

While endocrine steroid hormones have been known for many years to regulate normal and malignant mammary epithelium, recent studies have led to an appreciation of polypeptide growth factors as locally-acting autocrine and paracrine effectors. In the current article we summarize what is known about growth factor regulation and action in the normal mammary gland and about perturbations of the steroid-growth factor interplay as cancer progresses. A major theme is that oncogenic activation modulates both regulation of production and function of growth factors in the mammary gland.     

Production and characterization of mammary-derived growth factor 1 in mammary epithelial cell lines.

A mammary-derived growth factor, MDGF1, which stimulates collagen synthesis and proliferation in mammary epithelial cells was previously detected and purified from human milk and primary human breast tumors. MDGF1 binds to putative cell-surface receptors of 120-140 kDa and stimulates proliferation of normal and malignant human mammary epithelial cells. Partial protein sequence (N-terminal 18 amino acid sequence) shows that MDGF1 has no homology to any other known growth-promoting peptides. Polyclonal antiserum raised against this synthetic peptide recognizes native milk-derived MDGF1. We hypothesize that MDGF1 might be an autocrine or paracrine factor produced by and acting on normal and malignant human breast epithelial cells possessing MDGF1 receptors. As a first step in testing this possibility, we examined whether human breast epithelial cells in culture produce the growth factor. A protein with the size of MDGF1 was immunologically detected in the concentrated conditioned medium prepared from human breast cancer cell line MDA-MB 231, the mammary-derived but nontumorigenic HBL-100 line, and the normal reduction mammoplasty-derived, nonimmortalized 184 cell strain. A competitive radioreceptor assay (RRA) was used to estimate the level of MDGF1 in the conditioned medium. MDGF1 was present in the nanogram range per 1 million cells. A 62-kDa protein was detected in the above cell lysates by Western immunoblotting or by immunoprecipitation of metabolically labeled cell-conditioned media. The polyclonal antisera directed against the 18 amino acid peptide sequence from milk-derived MDGF1 could adsorb MDGF1 biological activity from conditioned medium. In vitro translation of cell mRNA yielded a protein of 55 kDa which was immunoprecipitated by anti-MDGF1 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)     

Toxoplasma gondii profilin and tachyzoites RH strain may manipulate autophagy via downregulating Atg5 and Atg12 and upregulating Atg7

Molecular Biology Reports - Autophagy process is an important defense mechanism against intracellular infection. This process plays a critical role in limiting the development of Toxoplasma gondii....     

Spherical Boundary Conditions: A Finite and System Size Independent Geometry for Simulations of Electrolytic Liquids

The system size dependence of the thermodynamic properties of electrolytic systems in "Spherical Boundary Conditions" (SBC) have been examined in this work. Coulombic systems were simulated with different system sizes (N ) for a wide range of concentrations, different ionic charges and solvent permittivities. The effects of system size upon the mean internal energy ?U? and mean ionic activity coefficient ?γ _±? values were determined. Our results indicated that there was no dependence of the thermodynamic properties upon system size in the non-Euclidean geometry. Different methods of extrapolating the thermodynamic properties to infinite numbers were studied in detail. In contrast to the Euclidean geometry, the method of extrapolating ?U? or ?γ _±? versus N ^-1, N ^-2/3 and N ^-1/3 was not statistically justifiable nor advantageous. Therefore, SBC is well suited to simulating systems involving long-range electrostatic interactions because the results do not dependent upon system size.     

A rapid,ideal, and eco-friendlier protocol for quantifying proline

Proline, a stress marker, is routinely quantified by a protocol that essentially uses hazardous toluene. Negative impacts of toluene on human health prompted us to develop a reliable alternate protocol for proline quantification. Absorbance of the proline-ninhydrin condensation product formed by reaction of proline with ninhydrin at 100 °C in the reaction mixture was significantly higher than that recorded after its transfer to toluene, revealing that toluene lowers sensitivity of this assay. λ _max of the proline-ninhydrin complex in the reaction mixture and toluene were 508 and 513 nm, respectively. Ninhydrin in glacial acetic acid yielded higher quantity of the proline-ninhydrin condensation product compared to ninhydrin in mixture of glacial acetic acid and H₃PO₄, indicating negative impact of H₃PO₄ on proline quantification. Further, maximum yield of the proline-ninhydrin complex with ninhydrin in glacial acetic acid and ninhydrin in mixture of glacial acetic acid and H₃PO₄ was achieved within 30 and 60 min, respectively. This revealed that H₃PO₄ has negative impact on the reaction rate and quantity of the proline-ninhydrin complex formed. In brief, our proline quantification protocol involves reaction of a 1-ml proline sample with 2 ml of 1.25 % ninhydrin in glacial acetic acid at 100 °C for 30 min, followed by recording absorbance of the proline-ninhydrin condensation product in the reaction mixture itself at 508 nm. Amongst proline quantification protocols known till date, our protocol is the most simple, rapid, reliable, cost-effective, and eco-friendlier.