Isolation and kinetic properties of 5′-nucleotidase from guinea-pig skeletal muscle

5′-Nucleotidase (EC 3.1.3.5) has been solubilized and purified 1200-fold from guinea-pig skeletal muscle, to a specific activity of 40 U/mg protein. The purified enzyme yields a single protein band on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Guinea-pig skeletal muscle 5′-nucleotidase is extremely sensitive to inhibition by nucleoside di- and triphosphates. The inhibition is of the competitive type, and can be reversed only by strong excess of Mg²⁺. Nucleoside diphosphates are more powerful inhibitors than nucleoside triphosphates. The K_i values for ADP and ATP are 0.036 and 0.28 μM, respectively. The purified enzyme does not require exogenous cations for maximal activity and is inhibited by EDTA. This inhibition is reversed by divalent cations. This indicates that the enzyme contains a tightly bound metal cation.     

HPA-axis activity in alcoholism: examples for a gene-environment interaction.

Genetic and environmental influences are both known to be causal factors in the development and maintenance of substance abuse disorders. This review aims to focus on the contributions of genetic and environmental research to the understanding of alcoholism and how gene-environment interactions result in a variety of addiction phenotypes. Gene-environment interactions have been reviewed by focusing on one of the most relevant environmental risk factors for alcoholism, stress. This is examined in more detail by reviewing the functioning of the hypothalamic-pituitary-adrenal (HPA) axis and its genetic and molecular components in this disorder. Recent evidence from animal and human studies have shown that the effects of stress on alcohol drinking are mediated by core HPA axis genes and are associated with genetic variations in those genes. The findings of the studies discussed here suggest that the collaborations of neuroscience, psychobiology and molecular genetics provide a promising framework to elucidate the exact mechanisms of gene-environment interactions as seen to convene upon the HPA axis and effect phenotypes of addiction.     

Morphometric distinction of granulomas in tuberculosis and sarcoidosis. Difference in nuclear profiles

Morphometric measurements were carried out on epithelioid-cell nuclei of noncaseating granulomas in paraffin-embedded sections of lymph node biopsy specimens originating from 15 patients with sarcoidosis and from 18 patients with tuberculosis. The results, which were obtained with the help of a computer-assisted tracing device, established highly significant differences in shape and size of epithelioid-cell nuclear profiles in these two diseases. Direct measurements and computations on these results showed that epithelioid-cell nuclear profiles in sarcoidosis have a smaller mean and median perimeter (boundary length), area and long diameter (maximum length of the nuclear profile) and exhibit a more plump, elliptical-like shape than do those in tuberculous granulomas. Epithelioid-cell nuclear profiles of the latter, as a whole, show more irregular contours, resembling those, e.g., of the sole of a shoe or other elongated patterns. Differences in shape of nuclear profiles were best demonstrated by a size-independent form factor (4 pi *area/perimeter2).     

Complete nucleotide mtDNA sequence of Barbary sheep (Ammotragus lervia).

In this report we describe the complete sequence of the mtDNA genome of Ammotragus lervia (Barbary sheep or aoudad) as obtained by PCR and sequencing with primer walking using flanking sequences. The molecule is 16,530 base pairs in length, resulting similar to those of goat and sheep. The genome organization matches to those of other mammalian mitochondrial genomes. The phylogenetic position of the Ammotragus relative to twelve other mammalian species was assessed based on protein-coding sequences. A goat-aoudad split of 9.9-8.9 MYBP has been estimated, whereas the divergence ancestor/caprines was dated at 12.1-10.8 MYBP.     

Starch content and distribution in excised watermelon cotyledons treated with benzyladenine

We have examined the effect of benzyladenine (BA) on amyloplast number and distribution in semithin cross-sections of excised watermelon ( Citrullus vulgaris Schrad ., cv. Fairfax) cotyledons grown in the dark. The sections were stained with Lugol solution and observed with an immersion objective. In control cotyledons, amyloplasts were always more abundant and contain more starch grains than in BA-treated cotyledons. The higher starch content was correlated with a higher ratio between starch synthetase (EC 2.4.1.21) and amylase (EC 3.2.1.1) activities in the controls. In the central zone of the mesophyll, the amyloplasts contained more starch grains than in the abaxial and adaxial (palisade) zones. The average number of amyloplasts per cell was different in the three zones, and followed a different time course in control and treated cotyledons. BA decreased this number, particularly in the adaxial zones. Our data seem to indicate a different function of starch in the central and in adaxial zone of the mesophyll. In the central zone starch is probably used as a source of carbohydrates for export to the embryo axis, while in the adaxial zone, where the transformation from amyloplast to etioplast is particularly pronounced, starch may be a reserve for organelle differentiation. BA stimulates the utilization of starch for both functions.     

Phenotypic characterization of Adig null mice suggests roles for adipogenin in the regulation of fat mass accrual and leptin secretion

1. Download : Download high-res image (116KB)
2. Download : Download full-size image

     

Unique corneal tomography features of allergic eye disease identified by OCT imaging and artificial intelligence

The purpose of this study was to assess unique corneal tomographic parameters of allergic eye disease (AED) using optical coherence tomography (OCT) and artificial intelligence (AI). A total of 57 eyes diagnosed with AED were included. The curvature and aberrations of the air‐epithelium (A‐E) and epithelium‐Bowman's layer (E‐B) interfaces were calculated. Random forest AI models were built combing this data with the parameters of healthy, forme fruste keratoconus (FFKC) and KC eyes. The AI models were cross‐validated with 3‐fold random sampling. Each model was limited to 10 trees. The AI model incorporating both A‐E and E‐B parameters provided the best classification of AED eyes (area under the curve = 0.958, sensitivity = 80.7%, specificity = 98.5%, precision = 88.2%). Further, the E‐B interface parameters provided the highest information gain in the AI model. A few AED eyes (n = 9) had tomography parameters similar to FFKC and KC eyes and may be at risk of progression to KC.