Assaying Total Carotenoids in Flours of Corn and Sweetpotato by Laser Photoacoustic Spectroscopy

This study describes the application of the laser photoacoustic spectroscopy (PAS) for quantification of total carotenoids (TC) in corn flours and sweetpotato flours. Overall, thirty-three different corn flours and nine sweetpotato flours were investigated. All PAS measurements were performed at room temperature using 488-nm argon laser radiation for excitation and mechanical modulation of 9 and 30 Hz. The measurements were repeated within a run and within several days or months. The UV–Vis spectrophotometry was used as the reference method. The concentration range that allows for the reliable analysis of TC spans a region from 1 to 40 mg kg−1 for corn flours and from 9 to 40 mg kg−1 for sweetpotato flours. In the case of sweetpotato flours, the quantification may extend even to 240 mg kg−1 TC. The estimated detection limit values for TC in corn and sweetpotato flours were 0.1 and 0.3 mg kg−1, respectively. The computed repeatability (n = 3–12) and intermediate precision (n = 6–28) RSD values at 9 and 30 Hz are comparable: 0.1–17.1% and 5.3–14.7% for corn flours as compared with 1.4–9.1% and 4.2–23.0% for sweetpotato flours. Our results show that PAS can be successfully used as a new analytical tool to simply and rapidly screen the flours for their nutritional potential based on the total carotenoid concentration

Congruence of tissue expression profiles from Gene Expression Atlas, SAGEmap and TissueInfo databases

BACKGROUND: Extracting biological knowledge from large amounts of gene expression information deposited in public databases is a major challenge of the postgenomic era. Additional insights may be derived by data integration and cross-platform comparisons of expression profiles. However, database meta-analysis is complicated by differences in experimental technologies, data post-processing, database formats, and inconsistent gene and sample annotation. RESULTS: We have analysed expression profiles from three public databases: Gene Expression Atlas, SAGEmap and TissueInfo. These are repositories of oligonucleotide microarray, Serial Analysis of Gene Expression and Expressed Sequence Tag human gene expression data respectively. We devised a method, Preferential Expression Measure, to identify genes that are significantly over- or under-expressed in any given tissue. We examined intra- and inter-database consistency of Preferential Expression Measures. There was good correlation between replicate experiments of oligonucleotide microarray data, but there was less coherence in expression profiles as measured by Serial Analysis of Gene Expression and Expressed Sequence Tag counts. We investigated inter-database correlations for six tissue categories, for which data were present in the three databases. Significant positive correlations were found for brain, prostate and vascular endothelium but not for ovary, kidney, and pancreas. CONCLUSION: We show that data from Gene Expression Atlas, SAGEmap and TissueInfo can be integrated using the UniGene gene index, and that expression profiles correlate relatively well when large numbers of tags are available or when tissue cellular composition is simple. Finally, in the case of brain, we demonstrate that when PEM values show good correlation, predictions of tissue-specific expression based on integrated data are very accurate

Na+, K+-ATPase genes are down-regulated during adipose stem cell differentiation.

The expression of Na+, K+-ATPase alpha and beta subunits isoforms, FXYD2 and FXYD7 were studied in rat adipose stem cell (ASC) by qRT-PCR and immunofluorescence. ASCs were able to differentiate to chondrocytes or adipocytes. All studied genes were expressed in freshly isolated ASCs and in all passages checked. Immunostaining for alpha1 isoform was found in plasma membrane and nuclear envelope, alpha2 signal was lower and alpha3 staining was variable among cells. Beta isoforms signal was abundant and displayed an isoform-specific picture. Staining for FXYD7 was homogeneous in plasma membrane and cytosol. Chondrocytes differenciated from ASC showed identical Na+, K+-ATPase subunits isoforms expression patterns to chondrocytes in cartilage. The expression pattern of Na+, K+-ATPase genes in ASCs exhibits a unique phenotypic signature that implies functional differences in Na+ and K+ transport rates. Furthermore, this phenotypic signature may also be used as a complementary marker for studies of mesenchymal stem cell differentiation. We propose a possible 'moonlighting' role of Na+, K+-ATPase beta isoforms that could be essential for the study of mesenchymal stem cell function and differentiation

Na+, K+-ATPase genes are down-regulated during adipose stem cell differentiation.

The expression of Na+, K+-ATPase alpha and beta subunits isoforms, FXYD2 and FXYD7 were studied in rat adipose stem cell (ASC) by qRT-PCR and immunofluorescence. ASCs were able to differentiate to chondrocytes or adipocytes. All studied genes were expressed in freshly isolated ASCs and in all passages checked. Immunostaining for alpha1 isoform was found in plasma membrane and nuclear envelope, alpha2 signal was lower and alpha3 staining was variable among cells. Beta isoforms signal was abundant and displayed an isoform-specific picture. Staining for FXYD7 was homogeneous in plasma membrane and cytosol. Chondrocytes differenciated from ASC showed identical Na+, K+-ATPase subunits isoforms expression patterns to chondrocytes in cartilage. The expression pattern of Na+, K+-ATPase genes in ASCs exhibits a unique phenotypic signature that implies functional differences in Na+ and K+ transport rates. Furthermore, this phenotypic signature may also be used as a complementary marker for studies of mesenchymal stem cell differentiation. We propose a possible 'moonlighting' role of Na+, K+-ATPase beta isoforms that could be essential for the study of mesenchymal stem cell function and differentiation

Nucleotide sequence of a cDNA for the [beta]2 subunit isoform of Na+, K+-ATPase from human retina

Using as probe the entire human liver cDNA clone coding for the the [beta]2 subunit isoform of the Na+,K+-ATPase, which lacks the initiation codon ATG, and the entire 5'-untranslated region (Martin-Vasallo, P., Dackowski, W., Emanuel, J.R. and Levenson, R. (1989) J. Biol. Chem. 264, 4613-4618), we isolated a larger clone from a directional human adult retina cDNA library (Swaroop, A. and Xu, J. (1993) Cytogenet. Cell Genet. 64, 292-294). This clone, pNH[beta]2, shows 100% homology with the nucleotide sequence of the human liver cDNA clone and also contains additional 407 nucleotides in the 5'-untranslated region, the initiation codon and a poly(A) tail. Northern blot hybridization analysis reveals that the human mRNA (3.6 kb) is approx. 300 nucleotides larger than the major transcript size expressed in rat (3.3 kb). The larger human size mRNA for the human [beta]2 Na+,K+-ATPase indicates species differences in gene processing.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31838/1/0000785.pd

Isoforms of Na+,K+-ATPase in primary human bone derived osteoblasts

Osteoblasts play a critical role in bone formation and mineralization, a process that depends on optimal calcium and phosphate homeostasis. Transcellular transport of free calcium [Ca2+], uptake of inorganic phosphate (P(i)) and numerous other transport systems in osteoblasts depend on a low intracellular Na+:K+ ratio furnished by (Na++K+)-stimulated adenosine triphosphatase (Na+,K+-ATPase), an enzyme embedded in the plasma membrane. In this study, we have examined, for the first time, the expression of the catalytic α and regulatory β subunit isoforms of Na+,K+-ATPase in primary human bone derived osteoblasts using isoform specific monoclonal and polyclonal antibodies. Immunofluorescence was used to detect the α1, β1 and β2 isoforms of Na+,K+-ATPase in dispersed osteoblasts. Laser scanning confocal microscopy also revealed an abundance of Na+,K+-ATPase isoforms in subcellular compartments. The existence of α1, β1 and β2 suggests that at least two major isozyme combinations of Na+,K+-ATPase are present in human bone (α1β1,α1β2)

Isoforms of Na+,K+-ATPase in primary human bone derived osteoblasts

Osteoblasts play a critical role in bone formation and mineralization, a process that depends on optimal calcium and phosphate homeostasis. Transcellular transport of free calcium [Ca2+], uptake of inorganic phosphate (P(i)) and numerous other transport systems in osteoblasts depend on a low intracellular Na+:K+ ratio furnished by (Na++K+)-stimulated adenosine triphosphatase (Na+,K+-ATPase), an enzyme embedded in the plasma membrane. In this study, we have examined, for the first time, the expression of the catalytic α and regulatory β subunit isoforms of Na+,K+-ATPase in primary human bone derived osteoblasts using isoform specific monoclonal and polyclonal antibodies. Immunofluorescence was used to detect the α1, β1 and β2 isoforms of Na+,K+-ATPase in dispersed osteoblasts. Laser scanning confocal microscopy also revealed an abundance of Na+,K+-ATPase isoforms in subcellular compartments. The existence of α1, β1 and β2 suggests that at least two major isozyme combinations of Na+,K+-ATPase are present in human bone (α1β1,α1β2)