Overlapping retrovirus U5 sequence elements are required for efficient integration and initiation of reverse transcription

A secondary structure in the 5' noncoding region of avian retrovirus RNA, called the U5-leader stem, was shown previously to have a role in initiation of reverse transcription (D. Cobrinik, L. Soskey, and J. Leis, J. Virol. 62:3622-3630, 1988). We now show that an additional RNA secondary structure near the U5 terminus, called the U5-IR stem, is also important for reverse transcription. Mutations that disrupt the U5-IR stem cause a replication defect associated with both a decrease in synthesis of viral DNA in infected cells and a decrease in initiation of reverse transcription in melittin-permeabilized virions. Structure-compensating base substitutions in the U5-IR restore reverse transcription efficiency. In viral DNA, U5-IR sequences are included in the U5 terminal region that functions as a viral integration donor site. When base substitutions are introduced into these sequences, a reduced efficiency of integration in vitro and in vivo is observed. These observations indicate that U5-IR sequences have a structural role in reverse transcription of viral RNA and a sequence-specific role in the integration of viral DNA.

Noncoordinate regulation of alpha-1 adrenoreceptor coupling and reexpression of alpha skeletal actin in myocardial infarction-induced left ventricular failure in rats

To determine the effects of myocardial infarction-induced left ventricular failure on the regulation of surface alpha-1 adrenoreceptors and signal transduction, large infarcts were produced in rats and the animals killed seven days later. After the documentation of impaired left ventricular pump performance, radioligand binding studies of the alpha-1 adrenoreceptor, norepinephrine-stimulated phosphoinositol turnover, and ADP ribosylation of 41 kD substrate by pertussis toxin were examined in the hypertrophying unaffected myocardium. Moreover, the expression of sarcomeric actin isoforms was analyzed by Northern blots and hybridization with specific oligonucleotide probes. Alpha-1 adrenoreceptor density was found not to be altered in membranes obtained from the spared left ventricular tissue, whereas phosphoinositol turnover was increased 3.1-fold in the viable myocytes of infarcted hearts. Furthermore, pertussis toxin substrate was augmented 2.5-fold in membranes prepared from the surviving left ventricular myocardium. Finally, an upregulation of the skeletal actin isoform was detected in the tissue of the failing left ventricle. In conclusion, the possibility is raised that in the presence of severe myocardial dysfunction and ongoing reactive hypertrophy, effector pathways linked to the alpha-1 adrenoreceptor may stimulate the myocyte hypertrophic response which would tend to normalize cardiac hemodynamics. The reexpression of alpha skeletal actin may be a molecular indicator of the persistance of an overload on the myocardium.

Parallel multiple matrix multiplication using an orthogonal shadow-casting and imaging system

A novel orthogonal shadow-casting and imaging optical system is proposed for performing multiple matrix multiplication. An analysis is given for describing the construction of a matrix processor. Preliminary experiments of matrix multiplication are demonstrated.

Quantitative analysis of correlations among flower traits in Gerbera hybrida Compositae : 1. Genetic and environmental correlations

Phenotypic (r p ), genetic (r g ), and environmental, (r e ) correlations were estimated for 38 flower traits in the Davis population of gerbera (Gerbera hybrida, Compositae). Fifty-two percent of r p and 38% of r g were statistically significant at P < 0.05. Significant negative r p were infrequent, but significant negative r g occurred in 10% of cases. There was a negative correlation between estimates of r g and r e , resulting in cases where r g was significant, but r p was not. Individual traits varied in their tendency to correlate phenotypically or genetically, and positively or negatively, with other traits. Traits within the same morphological category, such as disk florets or transitional florets, were more highly intercorrelated than were traits from different categories.

Quantitative analysis of correlations among flower traits in Gerbera hybrida, Compositae : 2. Direct and mean correlated response to selection

A Mean Correlation Response (MCR) model was developed to estimate the relative effectiveness of direct selection when other traits also respond to the selection. A measure of the relative effects of mean correlated response and direct response (R) and a measure of the relative efficiency of direct selection (IE) were applied to a genetic correlation matrix of 38 traits. These were measurements of inflorescence, receptacle and involucre, scape, disk florets, ray florets, and trans florets in the Davis population of Gerbera hybrida, Compositae. Generally, traits with high heritability had high direct and mean correlated response; these were often traits measuring disk and trans florets. Traits with low heritability had low direct and mean correlated response; these were often traits measuring the inflorescence. Traits of the inflorescence had the lowest efficiency of direct to mean correlated response.

[Immunisation of spontaneously hypertensive rats against angiotensin I]

Immunization against angiotensin I has been considered in comparison with the immunization against renin, in the spontaneously hypertensive rat (SHR). Among 6 different methods of immunization, two (AI-gluta-LPH and AI-Carbo-LPH coupling) permitted to obtain high levels of antibodies against angiotensin I (higher than 1/10,000), after four injections of 50 micrograms AI at three weeks interval. The titration of the antibodies was realized in radio-immuno-assay (RIA), with the determination of the cross-reactivity with AII by the same method. Characterization of the isotypes and the affinity calculation were realized with the ELISA method. The average level of antibodies is about 1/10,000 to 1/100,000, and the cross reactivity of the antibodies for AII is about 0.1 p. 100 in RIA. In ELISA, the study of the different isotypes shows a good maturation of the immune system with a sharp elevation of the IgG1 and IgG2 alpha isotypes, after 2 or 3 injections. The affinity of the antibodies purified by affinity chromatography is about 10.3 10(-9) M. The weekly measure of the arterial pressure during 6 months does not reveal at any moment a fall of pressure during the immunizations. The average pressure of the immunized group (209.4 +/- 23.8 mmHg, n = 40) is non significantly different from the average pressure of the mock group (208.5 +/- 22.6 mmHg, n = 10).

Elevation of glutathione levels and glutathione S-transferase activity in arsenic-resistant Chinese hamster ovary cells

Arsenic-resistant Chinese hamster ovary (CHO) cells were established by progressively increasing the concentration of sodium arsenite in culture medium. One of the resistant clones, SA7, was also cross-resistant to As(V), Zn, Fe(II), Co, and Hg. The susceptibilities to sodium arsenite in parental CHO cells, revertant SA7N cells, and resistant SA7 cells were correlated with their intracellular glutathione (GSH) levels and glutathione S-transferase (GST) activity. The resistance in SA7 cells was diminished by depletion of GSH in cells after treatment with buthionine sulfoximine. Furthermore, after reexposure of revertant SA7N cells to sodium arsenite, the intracellular GSH levels, GST activity, and resistance to sodium arsenite were raised to the same levels as SA7 cells. These data indicate that the elevation of intracellular GSH levels and GST activity in SA7 cells may be responsible for the resistance to arsenite. A p25 protein, which could be a monomer subunit of GST, accumulated in SA7 cells. In addition, an outward transport inhibitor, verapamil, indiscriminately increased the arsenite toxicity in resistant and parental cells.

Immunochemical quantitation of thymine glycol in oxidized and X-irradiated DNA

The present study demonstrates the usefulness of immunochemical assays for quantitating modified bases in oxidized and X-irradiated DNA. Escherichia coli, phi X174 RF I, PM2, and M13 DNA containing thymine glycols introduced by OsO4 oxidation were used as antigens in a direct enzyme-linked immunosorbent assay (ELISA). The number of thymine glycols per DNA molecule was determined by reactivity with antithymine glycol antibody standardized either to the acetol fragment assay or to the number of Escherichia coli endonuclease III-sensitive sites. The number of thymine glycols was also determined in phi X174 RF I DNA X-irradiated in either phosphate or Tris buffer under air. Using a direct ELISA with phi X174 RF I DNA irradiated in a phosphate buffer solution, the anti-thymine glycol antibody detected damage at the level of 40 Gy. The immunochemical assay was sensitive, specific, quantitative, and independent of DNA structure.

Trial of deltamethrin impregnated bed nets for the control of malaria transmitted by Anopheles sinensis and Anopheles anthropophagus

In 1985-1987, a field trial of malaria control using deltamethrin impregnated mosquito nets was carried out with 4,450 people in the Buji district, Bao'an County, Guangdong Province, China. The vectors were exophilic Anopheles sinensis (80%) and the endophilic and anthropophilic An. anthropophagus (20%). The first impregnation of the nets was in June 1985 and the second in April 1986. About 87% of the population slept under treated nets. The indoor vector density decreased by 93% and remained at the same level during the second year. During the second year the average monthly malaria incidence was 1.3% for January-June, a decrease of 74.6% as compared with pretreatment data, and 0.85% from July to December, a decrease of 92.7%. In April 1986 and April 1987, the treatment was extended to the whole Buji District, which has a total population of approximately 40,000. The average monthly malaria incidence (April-December 1986 and 1987) was 0.54% and 0.17%, a decrease of 64.7% and 89% respectively as compared with the same period for the previous year.