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).     

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

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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.     

The R117A variant of the Escherichia coli transacylase FabD synthesizes novel acyl-(acyl carrier proteins)

The commercial impact of fermentation systems producing novel and biorenewable chemicals will flourish with the expansion of enzymes engineered to synthesize new molecules. Though a small degree of natural variability exists in fatty acid biosynthesis, the molecular space accessible through enzyme engineering is fundamentally limitless. Prokaryotic fatty acid biosynthesis enzymes build carbon chains on a functionalized acyl carrier protein (ACP) that provides solubility, stability, and a scaffold for interactions with the synthetic enzymes. Here, we identify the malonyl-coenzyme A (CoA)/holo-ACP transacylase (FabD) from Escherichia coli as a platform enzyme for engineering to diversify microbial fatty acid biosynthesis. The FabD R117A variant produced novel ACP-based primer and extender units for fatty acid biosynthesis. Unlike the wild-type enzyme that is highly specific for malonyl-CoA to produce malonyl-ACP, the R117A variant synthesized acetyl-ACP, succinyl-ACP, isobutyryl-ACP, 2-butenoyl-ACP, and β-hydroxybutyryl-ACP among others from holo-ACP and the corresponding acyl-CoAs with specific activities from 3.7 to 120 nmol min⁻¹ mg⁻¹. FabD R117A maintained K _M values for holo-ACP (~ 40 μM) and displayed small changes in K _M for acetoacetyl-CoA (110 ± 30 μM) and acetyl-CoA (200 ± 70 μM) when compared to malonyl-CoA (80 ± 30 μM). FabD R117A represents a novel catalyst that synthesizes a broad range of acyl-acyl-ACPs.