The influence of chromosomal location on the expression of two transgenes in mice

We have generated mice having a single copy of the human haptoglobin gene (Hp2), driven by its natural promoter, and a neomycin resistance gene (Neo), driven by a herpes simplex thymidine kinase promoter with polyoma enhancers, inserted into two defined chromosomal locations, the Hprt locus on the X-chromosome and the apolipoprotein (apo) AI-CIII gene cluster on chromosome 9. The haptoglobin promoter is highly specialized in its tissue of action; the viral promoter has few restrictions. The apoAI-CIII gene is naturally active in only two tissues, whereas the Hprt gene region is ubiquitously active. Expression of both transgenes at substantial levels was achieved only (a) when the transgenes were inserted into the genome close to a known tissue-specific enhancer/locus control region in the apoAI-CIII gene cluster, and (b) when known conditions for function of their promoters were met. The specificities of the two chromosomal regions and of the two promoters are preserved, but their interactions are not specific. We conclude that transgenes are affected by locus-related enhancers in the same manner as nearby endogenous genes. Our experiments reinforce the usefulness of using gene targeting to direct single-copy transgenes to appropriate chromosomal locations.     

Characterization of two novel propachlor degradation pathways in two species of soil bacteria

Propachlor (2-chloro-N-isopropylacetanilide) is an acetamide herbicide used in preemergence. In this study, we isolated and characterized a soil bacterium, Acinetobacter strain BEM2, that was able to utilize this herbicide as the sole and limiting carbon source. Identification of the intermediates of propachlor degradation by this strain and characterization of new metabolites in the degradation of propachlor by a previously reported strain of Pseudomonas (PEM1) support two different propachlor degradation pathways. Washed-cell suspensions of strain PEM1 with propachlor accumulated N-isopropylacetanilide, acetanilide, acetamide, and catechol. Pseudomonas strain PEM1 grew on propachlor with a generation time of 3.4 h and a Ks of 0.17 +/- 0.04 mM. Acinetobacter strain BEM2 grew on propachlor with a generation time of 3.1 h and a Ks of 0.3 +/- 0.07 mM. Incubations with strain BEM2 resulted in accumulation of N-isopropylacetanilide, N-isopropylaniline, isopropylamine, and catechol. Both degradative pathways were inducible, and the principal product of the carbon atoms in the propachlor ring was carbon dioxide. These results and biodegradation experiments with the identified metabolites indicate that metabolism of propachlor by Pseudomonas sp. strain PEM1 proceeds through a different pathway from metabolism by Acinetobacter sp. strain BEM2.     

The chromosomal basis of sexual isolation in two sibling species of Drosophila: D. arizonensis and D. mojavensis

The chromosomal determination of interspecific differences in mating behavior was studied in the interfertile pair, Drosophila arizonensis and Drosophila mojavensis, by means of chromosomal substitutions. Interspecific crossing over was avoided by crossing hybrid males to parental females, and identification of the origin of each chromosome in backcrossed hybrids was possibly by means of allozyme markers. It was found that male mating behavior is controlled by factors located in the PGM-marked chromosome (which, in other Drosophila species, is part of the X chromosome) and in the Y chromosome. The other chromosomes influence male sexual behavior through their interactions with each other and with the PGM-marked chromosome, but their overall effect is minor. Female mating behavior is controlled by factors located in the ODH-marked and AMY-marked chromosomes, with the other chromosomes exercising a small additive effect. Hence, the two sex-specific behaviors are under different genetic control. Cytoplasmic origin has no effect on the mating behavior of either sex. There appears to be no correlation between a chromosome's structural diversity (i.e., amounts of inversion polymorphism within a species or numbers of fixed inversions across species) and its contribution to sexual isolation. These findings are in general agreement with those from similar Drosophila studies and may not be specific to the species studied here.     

Morphological and chromosomal descriptions of new species in the Anopheles subpictus complex

In the present work, the role of lipid peroxidation in cellular lethal injury induced by various types of oxidative stress has been studied in both normal and tumor thymocytes. The prooxidants included either a xanthine/xanthine oxidase system, which is an exogenous source of oxyradicals, or tert-butyl hydroperoxide (t-BOOH), which enters the cell and endogenously produces free radicals. Our data demonstrate that: (A) Using xanthine/xanthine oxidase system as a prooxidant, normal thymocytes are more sensitive than thymoma cells to oxidative damage, as their lactate dehydrogenase (LDH) and malondialdehyde (MDA) release is higher than that of tumor cells. By varying Fe3+/ADP ratios, a positive correlation can be established between LDH and MDA release only in normal thymocytes. While thymoma cells still show a very high level of vitamin E (80%) after 15 min of incubation with this prooxidant, normal thymocytes lose it after the same incubation time. (B) Using t-BOOH as a prooxidant, normal thymocytes release a higher amount of MDA but a lower amount of LDH than thymoma cells. In agreement with the results obtained with the xanthine/xanthine oxidase system, by varying the concentrations of the prooxidant, a correlation between LDH and MDA release can be established only in normal thymocytes. Although high levels of the antioxidant are still present in both kinds of cells after 15 min of incubation with t-BOOH, normal thymocytes consume vitamin E faster than thymoma cells. These data suggest that the role of lipid peroxidation in cell lethal injury is influenced by the source and the site of radical production as well as by the cell type. With t-BOOH as a prooxidant in normal thymocytes, lipid peroxidation is only partially involved in the induction of irreversible cell injury, but it plays a crucial role when the xanthine/xanthine oxidase system is used as a prooxidant. Moreover, whatever the prooxidant used in tumor thymocytes, membranes are more resistant to lipid peroxidation, suggesting that this mechanism is not causally related to cell death.     

Characterization and chromosomal mapping of two pseudogenes of the mouse Pafaha/Lis1 gene: retrointegration hotspots in the mouse genome

This study examines the relationship between trainees' conjugal family experience, current intergenerational family relationships, and the client's perception of the therapeutic alliance. Participants were 74 first practicum family therapy trainees, representing two family therapy programs, and 90 clients. Results indicated a moderately significant relationship between conjugal family experience and trainees' reported intergenerational intimacy with parents. Additionally, clients whose therapists had conjugal family experience reported a slightly more favorable therapeutic alliance than clients whose therapists did not have conjugal family experience. Additionally, trainees with conjugal family experience reported more current intimacy and individuation than nonconjugal trainees and felt less intimidated by their parents.     

Identification of two Shigella flexneri chromosomal loci involved in intercellular spreading

The ability of Shigella flexneri to multiply within colonic epithelial cells and spread to adjacent cells is essential for production of dysentery. Two S. flexneri chromosomal loci that are required for these processes were identified by screening a pool of TnphoA insertion mutants. These mutants were able to invade cultured epithelial cells but could not form wild-type plaques. Analysis of the nucleotide sequence indicated that the sites of TnphoA insertion were within two different regions that are almost identical to Escherichia coli K-12 chromosomal sequences of unknown functions. One region is located at 70 min on the E. coli chromosome, upstream of murZ, while the other is at 28 min, downstream of tonB. The mutant with the insertion at 70 min was named vpsC because it showed an altered pattern of virulence protein secretion. The vpsC mutant formed pinpoint-sized plaques, was defective in recovery from infected tissue culture cells, and was sensitive to lysis by the detergent sodium dodecyl sulfate. Recombinant plasmids carrying the S. flexneri vpsA, -B, and -C genes complemented all of the phenotypes of the vpsC mutant. A mutation in vpsA resulted in the same phenotype as the vpsC mutation, suggesting that these two genes are part of a virulence operon in S. flexneri. The mutant with the insertion at 28 min was interrupted in the same open reading frame as S. flexneri ispA. This ispA mutant could not form plaques and was defective in bacterial septation inside tissue culture cells.     

Thermal unfolding of three acclimation temperature-associated isoforms of carp light meromyosin expressed by recombinant DNAs

Differential scanning calorimetry (DSC) was performed to investigate thermodynamic properties of three carp fast skeletal light meromyosin (LMM) isoforms expressed in Escherichia coli by recombinant DNAs. Three isoforms were the 10 degreesC-, intermediate-, and 30 degreesC-type LMM predominantly expressed in carp acclimated to 10, 20, and 30 degreesC. The isoforms expressed in E. coli by recombinant DNAs exhibited a typical pattern of alpha-helix in CD spectroscopy with two minima at 222 and 208 nm. Moreover, the three isoforms formed paracrystals typical of LMM, suggesting that expressed proteins retained intact structural properties. When the LMM isoforms were subjected to DSC analysis, the 10 degreesC and 30 degreesC types showed endotherms having transition temperatures (Tm) at 35.1 and 39.5 degreesC, respectively, which are responsible for thermal unfolding of alpha-helix. The intermediate type exhibited two comparable endotherms with Tm values at 34.9 and 40.6 degreesC, implying that it has intermediate thermodynamic properties between those of 10 degreesC and 30 degreesC types. However, a chimeric LMM having the 10 degreesC and 30 degreesC type as N- and C-terminal halves, respectively, showed the DSC pattern typical of the whole 30 degreesC-type molecule. On the other hand, another chimeric LMM composed of the N-terminal 30 degreesC type and C-terminal 10 degreesC type gave the pattern of the full 10 degreesC type. These results suggest that thermodynamic properties of the C-terminal half largely account for thermal unfolding of the whole molecule.     

Characterization of nonrandom chromosomal gains and losses in multiple myeloma by comparative genomic hybridization

Clonal chromosomal changes in multiple myeloma (MM) and related disorders are not well defined, mainly due to the low in vivo and in vitro mitotic index of plasma cells. This difficulty can be overcome by using comparative genomic hybridization (CGH), a DNA-based technique that gives information about chromosomal copy number changes in tumors. We have performed CGH on 25 cases of MM, 4 cases of monoclonal gammopathy of uncertain significance, and 1 case of Waldenstrom's macroglobulinemia. G-banding analysis of the same group of patients demonstrated clonal chromosomal changes in only 13 (43%), whereas by CGH, the number of cases with clonal chromosomal gains and losses increased to 21 (70%). The most common recurrent changes detected by CGH were gain of chromosome 19 or 19p and complete or partial deletions of chromosome 13. +19, an anomaly that has so far not been detected as primary or recurrent change by G-banding analysis of these tumors, was noted in 2 cases as a unique change. Other recurrent changes included gains of 9q, 11q, 12q, 15q, 17q, and 22q and losses of 6q and 16q. We have been able to narrow the commonly deleted regions on 6q and 13q to bands 6q21 and 13q14-21. Gain of 11q and deletion of 13q, which have previously been associated with poor outcome, can thus be detected by CGH, allowing the use of this technique for prognostic evaluation of patients, without relying on the success of conventional cytogenetic analysis.     

Demonstration of presbycusis across repeated measures in a nonhuman primate species.

Over a period of 3 yrs, the authors repeatedly examined the progress of age-related hearing loss in 7 rhesus monkeys; 3 were 31 yrs old, 2 were 24 yrs old, and 2 were 9 yrs old. Pure-tone audiograms for 7 frequencies (.125, .500, 2.000, 4.000, 16.000, 22.667, and 32.000 kHz) were obtained by the psychophysical tracking method. Analysis indicated the presence of presbycusis in the older Ss. Ss demonstrating presbycusis showed a progressive decrement in the ability to detect higher frequencies and an overall hearing loss at all frequencies. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structure of the murine CD156 gene, characterization of its promoter, and chromosomal location

The murine cell surface antigen mCD156 is a glycoprotein that is expressed in monocytic cell lines and consists of a metalloprotease domain, a disintegrin domain, a cysteine-rich domain, and an epidermal growth factor-like domain in the extracellular region. The mCD156 gene is composed of 24 exons and 23 introns and spans approximately 14 kilobases. The first exon encodes most of the signal peptide sequence, and the transmembrane region is encoded by a single exon (19). In contrast, the other regions are composed of multiple exons. Of these, exons 7-12 and 12-15 encode a metalloprotease domain and a disintegrin domain, respectively. Sequence analysis of the 5'-flanking DNA revealed many potential regulatory motifs. Chloramphenicol acetyltransferase analysis demonstrated that nucleotides at positions -183, -334, and -623 contained cis-acting enhancing elements in a mouse monocytic cell line, aHINS-B3. Nucleotides at positions -183 and -390 contained elements responsible for lipopolysaccharide (LPS) inducibility, although several other 5'-flanking regions were also involved in LPS responsiveness. Regions -202, -507, and -659 play a role in interferon-gamma inducibility. Some of the potential regulatory motifs and other unknown cis elements may be involved in the constitutive expression, and LPS and interferon-gamma inducibilities. The mCD156 gene was mapped to chromosome 7, region F3-F4.     

Carcinoma of the lung in three brothers and two sisters

SETTING: Patients were recruited from Siriraj, Bamrasnaradura, and Central Chest Hospitals, the three major hospitals responsible for tuberculosis patients in Bangkok, Thailand, and vicinity. OBJECTIVE: To evaluate a new rapid serologic test, the MycoDot test, for diagnosis of tuberculosis (TB). DESIGN: The study was conducted as a cross-sectional survey. A total of 594 patients were tested with the MycoDot test. This included 142 human immunodeficiency virus (HIV) seropositive patients with active TB, 144 HIV seronegative patients with active TB, 153 HIV seropositive controls, and 155 HIV seronegative controls. RESULTS: The sensitivity of the MycoDot test for detection of TB was 40.1% in HIV seropositive patients, compared with 63.2% in HIV seronegative patients (P < 0.001). If only patients with laboratory proven TB were evaluated, the sensitivity was 40.6% in seropositive and in 70.8% seronegative patients. The sensitivity of the MycoDot test was similar in TB patients with pulmonary and extra-pulmonary disease. The sensitivity of the test in patients with CD4 counts > or = 200 cells/mm3 was significantly higher than in those with CD4 counts < 200 cells/mm3. The specificity of the test was 97.4%, and was identical in HIV seropositive and seronegative individuals. CONCLUSION: The MycoDot test had a higher sensitivity for the diagnosis of TB among HIV seronegative than HIV seropositive patients. Although the MycoDot test has a less than optimal sensitivity, the test specificity approaches 100%. It may be useful in patients with suspected TB and negative smears and in extra-pulmonary TB.