Tissue-specific expression of the human alpha 1-antitrypsin gene is controlled by multiple cis-regulatory elements

Human alpha 1-antitrypsin (AAT) is expressed in the liver, and a 318 bp fragment immediately flanking the CAP site of the gene was found to be sufficient to drive the expression of a reporter gene (CAT) specifically in hepatoma cells. The enhancing activity however, was orientation-dependent. The DNA fragment was separated into a distal region and a proximal region. A "core enhancer" sequence GTGGTTTC is present within the distal region and is capable of activity enhancement in both orientations when complemented by the proximal region in the sense orientation. The results strongly suggest that there are multiple cis-acting elements in the human AAT gene that confer cell specificity for its expression. Nuclear proteins prepared from the hepatoma cells bound specifically to the proximal region in a band-shifting assay that was resistant to competition by the globin promoter DNA. Foot-printing analysis showed a protected domain within the proximal region that contains a nearly perfect palindromic sequence TGGTTAATATTCACCA, which may be important in the regulation of AAT expression in the liver.

Effects of fluoride on the mouse sperm morphology test

There has been little information and much confusion regarding the genotoxic effects of fluoride. The purpose of this study was to examine the spermatogenic influence of sodium fluoride (NaF) on the germ cells by means of the mouse sperm morphology test. Male mice of genotype B6C3F1 were obtained at about eight weeks of age and maintained on a low-fluoride diet (less than 0.2 ppm F) and distilled water ad libitum throughout the experiment. At approximately 13 weeks of age, the animals were randomly assigned to eight groups. Group I was intubated with the Maximum Tolerable Dosage (MTD) of NaF (70 mg/kg). Groups II through VI received NaF by stomach intubation at doses of 35, 20, 10, 1, and 0.1 mg/kg, respectively. Group VII served as a negative control and was intubated with distilled water. The positive control, Group VIII, was exposed to a known mutagen, cyclophosphamide (20 mg/kg, i.p.). The animals were treated daily for five days, and killed by cervical dislocation 35 days after the first exposure to chemicals. Slides of sperm from the cauda epididymides were prepared and blindly scored for morphological abnormalities. Weight of the testes was recorded, and the femurs were saved for fluoride (F) analysis. Analysis of bone F demonstrated the effective absorption of fluoride following intubation. The counts of abnormal sperm and the weights of the testes for mice exposed to NaF doses up to the MTD were not significantly different from those of the negative control. The results of this study showed that NaF did not have adverse effects on mouse sperm morphology.

Digital optical isochronous array processing

An optical isochronous array processing method is proposed. An optical isochronous array processor (OIAP) is a local regularly interconnected processing network that employs an array of identical optical processing elements. In an OIAP, incoming isochronous data are parallel processed in a fashion much like a propagating electromagnetic wavefront. For the various applications, the OIAP processing elements and their interconnections can be different. In this paper, various all-optical OIAP elements are considered. Applications ranging from optical binary number multiplication preprocessing to optical matrix algebra as well as to optical residue arithmetic are presented.

Human interstitial retinol-binding protein (IRBP): cloning, partial sequence, and chromosomal localization

A cloned 2184-bp cDNA coding for human interstitial retinol-binding protein (IRBP) has been isolated and sequenced. The probe hybridized to a 5.2-kb poly(A) RNA from human retinas. Nineteen tryptic peptides (363 amino acids) sequenced and purified from bovine IRBP could be aligned with 86-88% homology to the translated sequence. Two segments approximately 200 amino acids long were found to have a 41% residue identity, suggesting an internal duplication event. This cloned cDNA was used to probe DNA samples from a panel of 29 rodent-human somatic cell hybrids, mapping the structural gene for IRBP to chromosome 10. In situ hybridization suggested a regional localization near the centromere (p11.2----q11.2), although a secondary site of hybridization at q24----25 was also observed.

The chicken vimentin gene. Nucleotide sequence, regulatory elements, and comparison to the hamster gene

Here we report the nucleotide sequence of the chicken vimentin gene and its deduced primary amino acid sequence. A comparison of this gene to other intermediate filament protein genes demonstrates that both exon size and position are strongly conserved features of this multigene family. In addition, the hamster and chicken vimentin genes exhibit strong identity at the level of nucleotide (74%) and amino acid (80%) sequence. Interestingly, 40% of total sequence diversity is localized to the N terminus or "head" region of these genes whereas other protein domains (rod and C terminus) are remarkably identical in both nucleotide (81%) and amino acid (89%) sequence. Even stronger amino acid identity (100%) is exhibited in certain subdomains which may define regions crucial for filament formation and function. Not surprisingly, vimentin is more homologous across animal species than it is to other intermediate filament protein members (e.g. desmin) within the same species. A comparison of 5'-flanking sequences of the hamster and chicken genes as well as other characterized promoter elements (SV40, HSV-TK) reveals homologous sequence elements which may define common and/or unique sites involved in the modulation of gene expression. The implications of these sequence elements for both tissue-specific and developmental expression of the vimentin gene are discussed.

Conditional symbolic modified signed-digit arithmetic using optical content-addressable memory logic elements

A new conditional symbolic substitution rule for modified signed-digit arithmetic computation is introduced. Using this substitution rule, the numbers to be added or subtracted are first replaced by a pair of new equivalent strings, which in a second step are then subject to another substitution to generate both the addition or subtraction result and its complement. For an optical implementation, a holographic contentaddressable memory is used. Correspondingly, the input encoding, the logic reduction, and the optical processing techniques are described.

Bgl II RFLP recognized by a human IRBP cDNA localized to chromosome 10

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Absence of mutagenic and antimutagenic activities of fluoride in Ames salmonella assays

The mutagenicity of fluoride (as sodium fluoride, NaF) was investigated with Ames Salmonella/microsome assays in strains of TA97a, TA98, TA100, TA102 and TA1535. The concentrations of NaF tested ranged from 0.44 to 4421 micrograms/plate (0.1 to 1000 ppm F), both with and without microsome activation. In addition, the suggested antimutagenic effect of fluoride was evaluated with known mutagens at various concentrations of NaF (0.44-442.2 micrograms/plate, 0.1-100 ppm F). The data showed that NaF, in amounts from 0.44 to 442.2 micrograms/plate (0.1-100 ppm F), failed to significantly increase the number of the revertants over the number observed in the solvent (distilled deionized water) controls. Increases of NaF to, and beyond, 1100 micrograms/plate (250 ppm F) resulted in a toxic effect and a reduction of the revertants to various degrees among the strains. NaF in the presence of known mutagens did not significantly decrease the number of the revertants. The results of this study indicate that NaF does not have mutagenic or antimutagenic effects in the strains tested with Ames Salmonella assays.

Disease specificity of nondefective Friend and Moloney murine leukemia viruses is controlled by a small number of nucleotides

Moloney murine leukemia virus induces T cell lymphomas after injection into NFS mice, whereas the nondefective Friend virus induces erythroleukemias. Previous studies showed that sequences encompassing the viral transcriptional signals in U3 are the primary determinant of this phenotype in recombinants between these two viruses. To more precisely identify the sequences responsible, we constructed additional recombinants, within U3, between Friend and Moloney viruses and assayed these recombinants for for their disease specificity. We found that a fragment 191 bases long that included the direct repeat (enhancer) region plus 22 nucleotides to its 3' side from Friend virus was sufficient to convert Moloney virus to a virus that induced only erythroleukemias. A 171-base-long fragment of Moloney virus, including just the direct repeat, converted Friend virus to a virus that induced primarily lymphomas (about 85% of mice injected). We also constructed Moloney and Friend virus variants with one rather than two copies of the enhancer element. These viruses retained their disease specificity, although they exhibited a marked increase in the latent period of disease induction. Together the results suggest that 25 or fewer nucleotide differences, lying within and also just 3' of the direct repeat, are the primary determinant of the distinct disease specificities of nondefective Friend and Moloney viruses.

A new procedure for the purification of monodisperse highly active cytochrome c oxidase from bovine heart

A simple and rapid method for the isolation of a large quantity of cytochrome c oxidase from bovine heart mitochondria was developed, based on selective solubilization of mitochondrial protein with first Triton and then lauryl maltoside. Gel filtration shows that the lauryl maltoside-solubilized oxidase preparation is in a hydrodynamically homogeneous state with a Stokes radius of 7.5 +/- 0.2 nm. It contains 8.0 mumol of haem (with an a/a3 ratio of 1)/g of protein. The catalytic constant (maximum turnover number) with respect to cytochrome c approaches 600 S-1. After further purification of the solubilized enzyme on a sucrose-gradient centrifugation, the purified enzyme has a haem content of 10.3 mumol/g of protein and eight major polypeptide bands shown on SDS/polyacrylamide-gel electrophoresis.

Effect of exercise training on resting blood pressure and heart rate in adult and aged rats

To test the hypothesis that advancing age may have an effect on cardiovascular adaptation (resting blood pressure and heart rate) in response to exercise training, we compared adult (4.5 months at start of training) and aged (21.5 months at start of training) male Fischer 344 rats exercised on a rodent treadmill 5 days/week for 9 weeks. Two additional age-matched control groups were similarly handled and placed on the nonmoving treadmill for the same duration. Chronic exercise did not alter blood pressure in the adult group but lowered resting blood pressure in the aged rats during the midportion of the training period. On the other hand, the adult group demonstrated a significant decrease in the resting heart rate from Weeks 3 through 7 during training, whereas the aged group showed no change in resting heart rate during the entire study. These findings suggest that there may exist an age-related difference in the effect of exercise training on basal cardiovascular homeostasis, which is cardioinhibitory in the adult and vasodepressant in the aged.