The positive-acting sulfur regulatory protein CYS3 of Neurospora crassa: nuclear localization, autogenous control, and regions required for transcriptional activation

The positive-acting global sulfur regulatory protein, CYS3, of Neurospora crassa turns on the expression of a family of unlinked structural genes that encode enzymes of sulfur catabolism. CYS3 contains a leucine zipper and an adjacent basic region (b-zip), which together constitute a bipartite sequence-specific DNA-binding domain. Specific anti-CYS3 antibodies detected a protein of the expected size in nuclear extracts of wild-type Neurospora under conditions in which the sulfur circuit is activated. The CYS3 protein was not observed in cys-3 mutants. Nuclear extracts of wild type, but not cys-3 mutants, also showed specific DNA-binding activity identical to that obtained with a CYS3 protein expressed in Escherichia coli. A truncated CYS3 protein that contains primarily the b-zip domain binds to DNA with high specificity and affinity in vitro, yet fails to activate gene expression in vivo, and instead inhibits the function of the wild-type CYS3 protein. Amino-terminal, carboxyterminal, and internal deletions as well as alanine scanning mutagenesis were employed to identify regions of the CYS3 protein that are required for its trans-activation function. Regions of CYS3 carboxy terminal to the b-zip motif are not completely essential for function although loss of an alanine-rich region results in decreased activity. All deletions amino terminal to the b-zip motif led to a complete loss of CYS3 function. Alanine scanning mutagenesis demonstrated that an unusual prolinerich domain of CYS3 appears to be very important for function and is presumed to constitute an activation domain. It is concluded that CYS3 displays nuclear localization and positive autogenous control in Neurospora and functions as a trans-acting DNA-binding protein.     

Aneurysms of splanchnic arteries

Aneurysms of splanchnic arteries represent an uncommon but important vascular disease, which many times presents itself as clinical emergency and often results in death. 11 patients with splanchnic aneurysms were treated in our Department during the last 15 years. These aneurysms were located in 5 cases in splenic artery, 4 cases in hepatic artery, 1 case in celiac axis and 1 case in right gastroepiploic artery. Surgical treatment of these aneurysms was successful in all but one patient (he died from rupture of a hepatic artery aneurysm). Giving an overall mortality similar to that reported in the literature. The treatment of these aneurysms is discussed, while literature about this uncommon disease is reviewed.     

The key informant technique

The clinical outcome of 152 patients aged 65 years or over who were referred to the author's institute between August 1990 and August 1991 with certain specified gastrointestinal malignancies and acute, life-threatening abdominal conditions, were audited concurrently. Two groups were considered: patients aged 65-79 years and those over 80 years. The mortality rate within 30 days of surgery was 14 per cent in both age groups, although significantly fewer patients aged over 80 years (35 of 54) were considered suitable for surgery than in the 65-79 years age group (84 of 98) (0.01 > P > 0.001). Morbidity after operation and cost of treatment were not significantly different between the two groups. Two years after surgery 40 per cent of the patients aged over 80 years and 58 per cent of those aged 65-79 years were alive. Quality of life in these survivors was good with 85 per cent of those aged over 80 years living at home and 72 per cent fit enough to undertake light work.     

The chicken beta-globin gene promoter forms a novel "cinched" tetrahelical structure

We have previously shown that the G-rich sequence G16CG(GGT)2GG in the promoter region of the chicken beta-globin gene poses a formidable barrier to DNA synthesis in vitro (Woodford et al., 1994, J. Biol. Chem. 269, 27029-27035). The K+ requirement, template-strand specificity, template concentration independence, and involvement of Hoogsteen bonding suggested that the underlying basis of this new type of DNA synthesis arrest site might be an intrastrand tetrahelical structure. However, the arrest site lacks the four G-rich repeats that are a hallmark of previously described intramolecular tetraplexes and contains a number of noncanonical bases that would be expected to greatly destabilize such a structure. Here we report evidence for an unusual K+-dependent intrastrand "cinched" tetraplex. This structure has several unique features including the incorporation of bases other than guanine into the stem of the tetraplex, interaction between loop bases and bases in the flanking region, and base pairing between bases 3 and 5 of the tetrahelix-forming region to form a molecular "cinch." This finding extends the range of sequences capable of tetraplex formation as well as our appreciation of the conformational complexity of the chicken beta-globin promoter.     

Supramalleolar osteotomy for ankle valgus in myelomeningocele

Oral fibroblasts stimulated invasion of oral-carcinoma cells into the collagen matrix. The mechanisms of the fibroblast-induced stimulation of invasiveness was further investigated by examining cell motility and proteolytic activity of tumor cells, using mainly an adenoid-cystic-carcinoma cell line (ACCS) and normal fibroblasts from gingival tissues. Conditioned medium from the fibroblasts grown in serum-free medium was fractionated on a Superdex 200 pg column, and Peak 1 eluted at 200 to 300 kDa and Peak 2 eluted at 50 to 100 kDa were found to contain different specific activity. Treatment of ACCS cells with Peak 1 resulted in an increase in the production of proteolytic enzymes. Peak 2 stimulated both chemotaxis and chemokinesis of ACCS cells. A chemotactic factor was purified from the heparin-unbound fraction of Peak 2 by anion exchange and hydrophobic chromatography, and was named "fibroblast-derived motility factor (FDMF)". At 1 microg/ml, FDMF stimulated chemotaxis of ACCS cells by 4-fold compared with unstimulated controls. Characterization of the physicochemical properties of FDMF suggested that it might be different from any known motility factors. Exposure of ACCS cells to FDMF resulted in reduced amounts of actin stress fiber in the cytoplasm and induction of tyrosine phosphorylation of several cellular proteins detectable 30 to 60 min after treatment. These FDMF-induced changes were blocked by pre-treatment either with genistein or with pertussis toxin. These findings suggest that FDMF may be a novel protein which stimulates cell motility via a signaling pathway mediated by a pertussis-toxin-sensitive G protein and tyrosine phosphorylation.     

Characteristic features of excitation and propagation of acoustic modes in piezoelectric plates

Excitation and propagation of the I.V. Anisimkin and Lamb acoustic plate modes of various orders n has been experimentally investigated using, as an example, rotated 128° YX LiNbO₃ piezoelectric plates. It is shown that (1) an increase in the number of fingers of the interdigital transducers improves the frequency resolution of the neighboring modes with close velocities, (2) the use of aluminum as a finger material reduces the ripple of the mode amplitude-frequency characteristics (AFC) _n as compared to that in the case of gold fingers, and (3) the propagation loss increases with the distance and mode number n. It has been found that group velocities (v _g) _n and phase velocities (v _p) _n of the modes excited and received on the same surface of the plate do not change with distance starting, at least, from a 25-wavelength distance from the radiator. It has been established that, if the electrically conducting fluid is deposited on the opposite side of the plate, the shape of the (AFC) _n , central frequency f _n , and the phase characteristics of certain modes undergo changes that depend on whether the areas under the transducers are also covered with the fluid and on the distance between the transducers. No noticeable reflection of the modes from the plate edges has been recorded.     

In vivo fluoride profiles at different sites of buccal and lingual enamel surfaces obtained by enamel biopsy of human maxillary first permanent molars in young adults

Twenty male volunteers, average age 24 years, participated in this study. Specimens were obtained by enamel biopsy using 5 microliters of 0.5 M HClO4 for 30 s. Using a regression curve, comparisons of fluoride concentrations were made at different depths. The fluoride concentrations (mean +/- SE) at a depth of 5 microns were highest in the distobuccal (1698 +/- 136), high in the mesiobuccal (1343 +/- 122), low in the distolingual (1119 +/- 107), and lowest in the mesiolingual sites (819 +/- 78). Of the interior enamels (> or = 10 microns in depth), the distobuccal site (1330 +/- 88 parts/10(6) F at 10 microns) had a higher-concentration than all other sites. The fluoride profiles were steepest to shallowest in the order: distobuccal, mesiobuccal, distolingual and mesiolingual. There were no correlations between the enamel fluoride concentrations and the fluoride concentration in parotid saliva. It was concluded that in vivo fluoride profiles of maxillary first molars reflect the wear of the tooth surface with age and the condition of dental plaque deposition, and, to some extent, the site-specific distribution of saliva between buccal and lingual surfaces.