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[Effect of a glutamate and glutamine excess on the nucleic acid content of the spleen cell nuclei in rats].

In tests conducted with albino rats subject to investigation was the effect of sodium glutamate, or glutamine, daily introduced into the stomach in doses of 300 and 150 mg/kg, on the nucleic acids content in the splenic cell nuclei. All the animals taken in the experiment demonstrated a clearcut quantity of nucleonic RNA. By using a maximum dose of sodium glutamate and minimal one of glutamine a rise in the amount of DNA occurs in the nuclei of the splenic cells.

Animals↗

Establishment of cDNA microarray analysis at the Genomic Medicine Research Core Laboratory (GMRCL) of Chang Gung Memorial Hospital.

BACKGROUND: Advances in molecular and computational biology have led to the development of powerful, high-throughput methods for analysis of differential gene expression, which are opening up new opportunities in genomic medicine. DNA microarray technology has been enthusiastically integrated into basic biomedical research and will eventually become a molecular monitoring tool for various clinical courses. METHODS: As a core research facility of Chang Gung University (CGU) and Chang Gung Memorial Hospital (CGMH), the Genomic Medicine Research Core Laboratory (GMRCL) welcomes investigators from every discipline to employ DNA microarray technology in the quest for knowledge of genomic medicine. The first tasks for GMRCL are to optimize the standard operating procedures (SOP) for each instrument and to assure the quality of every procedure. RESULTS: During the first year after the establishment of the GMRCL at the CGMH, we tested and adopted procedures that were satisfactory for our purposes. These procedures included: replication of bacterial stocks, amplification of human DNA clones, annotation of each DNA clone, production of cDNA microarrays, validation of RNA quality and quantity, labeling of target specimens, competitive hybridization, scanning of slides, data analysis, and post-microarray validation of results. We present a summarization of the materials and procedures used at the GMRCL and discuss the reasons for using them. CONCLUSIONS: The information about the cDNA microarray analysis system at the GMRCL is compliant with the minimal information about a microarray experiment (MIAME) format. The information may be useful to both the investigators who are using this core facility and researchers at other institutes, who will establish their own in-house cDNA microarray systems.

Humans↗

Expression of the major surface glycoprotein of Leishmania donovani chagasi in virulent and attenuated promastigotes.

Using both hamster and mouse models of infection, we documented that the virulence of Leishmania donovani chagasi promastigotes decreases over time, when parasites are maintained in long term culture after isolation from an infected animal. Concomitant with this loss of virulence is a marked decrease in amount of the major promastigote surface glycoprotein, gp63, present in promastigotes. The latter was shown by a decrease in binding of polyclonal anti-gp63 serum to attenuated (cultivated long term) as compared to virulent (recently isolated) promastigotes, using immunofluorescence and Western blot assays. Binding of Con A to promastigote glycoproteins, separated by SDS-PAGE, documented a similar decrease. An alteration in the mechanism of promastigote attachment to macrophages was also noted: purified gp63 inhibited attachment of virulent promastigotes to human monocyte-derived macrophages, but it did not affect the attachment of attenuated promastigotes. Northern blot analysis showed that, despite marked differences in the amount of gp63 protein, the quantity of gp63 RNA was comparable in attenuated and virulent promastigotes. However, virulent promastigotes contained two major gp63 RNA species of 3.0 and 2.7 kb, whereas attenuated promastigotes had one predominant gp63 RNA of 2.7 kb and only minor amounts of 3.0 kb RNA. Thus, the decrease in gp63 expression in attenuated, contrasted to virulent, promastigotes is associated with qualitative, but not quantitative, differences in the gp63 messenger RNA.

Animals↗

Corticosteroid induction of Ig+Ia- B cells in vitro is mediated via interaction with the glucocorticoid cytoplasmic receptor.

Flow microfluorometry was used to examine the effect of dexamethasone on the expression of surface Ia (sIa) on resting and activated murine B cells. Although dexamethasone resulted in a 50% reduction in sIa expression 12 h after injection, it was significantly less suppressive when injected together with B cell activators. In vitro dexamethasone, but not other related steroid hormones, induced a population of cells that were sIg+sIa-. A 20% reduction in the expression of sIa was noted by 4 h of culture with 10 nM dexamethasone, but maximal inhibition of 70% was not reached until 12 h of culture, and this degree of suppression persisted as long as dexamethasone remained in culture. When the dexamethasone was washed out after 8 h of culture, the maximal reduction was still noted at 12 h, but by 24 h there was re-expression of sIa toward base line levels, indicating it did not induce irreversible lethal alterations in the B cell. The inhibition of sIa expression correlated with a specific reduction in the quantity of messenger RNA for sIa as measured by Northern blot analysis, indicating that this is mediated at least in part by suppression of the steady state levels of Ia mRNA. The corticosteroid receptor antagonist RU486 was able to reverse the suppressive effects of dexamethasone on sIa expression, thus demonstrating that its effect is mediated specifically by binding to its intracellular receptor. Furthermore, when protein synthesis was inhibited during the short period of time that cells were preincubated with dexamethasone, minimal suppression of Ia expression was noted, suggesting that the dexamethasone may be stimulating a protein that has suppressive effects on MHC class II expression. The suppressive effects of dexamethasone in vitro were substantially reduced when B cells were simultaneously activated by stimuli that increase the expression of sIa. These data indicate that the suppressive effects of corticosteroids on immune response Ag are corticosteroid specific; are greater in resting than in activated B cells; are induced via the classical steroid mechanism of action, which is receptor mediated; and may result from the induction of an inhibitory protein that suppresses Ia mRNA.

Animals↗

[Effect of mineral substances on the biological value of eggs].

The experiments on pure-strain laying hens of meat direction showed that the mineral supplement consisting of sodium metasilicate, sodium sulfate, sodium bicarbonate and sodium selenite added to the standard feed of PK-1-26 composition improved the biological value of incubation eggs as a results of the increased quantity of glycogen, RNA, total lipids and carotenoids. This promotes and increase in hatchability of chicken by 0.45%.

Animal Nutritional Physiological Phenomena↗

Quantitative determination of gene expression in human lymphocytes assessed by reverse transcription-polymerase chain reaction coupled to high-performance liquid chromatography.

Gene expression in human lymphocytes was assessed using reverse transcription and polymerase chain reaction amplification followed by ion-pair reversed-phase chromatography analysis. Competitive PCR was used to quantitate the desired cDNAs with a polivalent competitor adaptable to multiple novel mRNAs estimations with minor changes. Accuracy was 11.27+/- 11.87% (n = 7), as determined using standards. The coefficients of variation of the assessment of human OK12b were 7% (n = 6), 7.68 attmol/microg of total RNA, and 21% (n = 6), 0.93 attmol/microg of total RNA. Sample-to-sample variation in the reverse transcription and in the quantity and quality of RNA was attenuated by normalising results to beta-actin mRNA expression. The correlation between the OK12b/beta-actin ratio and competitive assessments of OK12b was 0.984, n = 6. The correlation between HPLC results and an independent method based on radionuclide uptake by the product, detected by electrophoretic separation, was 0.848, n = 10.

Base Sequence↗

Purification and partial characterization of the DNA-dependent RNA polymerase from Rickettsia prowazekii.

The DNA-dependent RNA polymerase was purified from Rickettsia prowazekii, an obligate intracellular bacterial parasite. Because of limitation of available rickettsiae, the classical methods for isolation of the enzyme from other procaryotes were modified to purify RNA polymerase from small quantities of cells (25 mg of protein). The subunit composition of the rickettsial RNA polymerase was typical of a eubacterial RNA polymerase. R. prowazekii had beta' (148,000 daltons), beta (142,000 daltons), sigma (85,000 daltons), and alpha (34,500 daltons) subunits as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The appropriate subunits of the rickettsial RNA polymerase bound to polyclonal antisera against Escherichia coli core polymerase and E. coli sigma 70 subunit in Western blots (immunoblots). The enzyme activity was dependent on all four ribonucleoside triphosphates, Mg2+, and a DNA template. Optimal activity occurred in the presence of 10 mM MgCl2 and 50 mM NaCl. Interestingly, in striking contrast to E. coli, approximately 74% of the rickettsial RNA polymerase activity was associated with the rickettsial cell membrane at a low salt concentration (50 mM NaCl) and dissociated from the membrane at a high salt concentration (600 mM NaCl).

Blotting, Western↗

The relative amounts of the cytoplasmic RNA species in normal, transformed and senescent cultured cell lines.

We have examined the relative quantities of 18S and 28S rRNA, 4S RNA and poly (A) + mRNA in the following cultured cells: the mouse fibroblast lines 3T3 and 3T6 in the resting (contact inhibited) and growing (sparse) states, 3T3 clones transformed with SV40 (SV3T3) and with both SV40 and polyoma SV-Py 3T3), hamster lung fibrobalsts (v79), human cervical carcinoma cells (HeLa), and human diploid fibroblasts at early and late passage. The relative quantities of the RNA species were determined by labeling the cells to equilibrium with 32PO4 and measuring the amount of label in each RNA species. The ratio of mRNA to rRNA varied form 1.1% to 2.7% in the different cell lines, the more rapidly growing cell lines usually giving a higher ratio. In cells experiencing growth limitation either by contact inhibition or due to senescence, the ratio of mRNA to rRNA was about 30% lower than in the corresponding cells in the growing state. In most cell lines the ratio of 4S RNA to 18S rRNA was between 0.8 and 1.2, but in seescent fibroblasts, this ratio increased to greater than 1.7. Senescent fibroblasts also contained much more total RNA per unit of DNA than the same cells at early passage or than 3T6 or 3T3 cells.

Animals↗

Studies on the function of the non-primer tRNAs associated with the 70 S RNA of avian myeloblastosis virus.

Significant amounts of three tRNAs are associated with the 70 S RNA of avian myeloblastosis virus (AMV). The temperatures at which they are half dissociated from the 70 S RNA in 50 mM NaCl and their respective quantities relative to 35 S RNA are: tRNAArg, 51 degree C, 1.6; tRNALys, 57 degree C, 0.7 and tRNATrp, 76 degree C, 1.0. Possible functions for the non-primer tRNAs (tRNAArg and tRNALys) were evaluated by determining the effect of their thermal dissociation on: (a) conversion of 70 S to 35 S RNA, (b) capacity of 70 S and/or 35 S RNA to be translated in vitro, and (c) capacity of 70 S and/or 35 S RNA to be reverse transcribed in vitro. Conversion of 70 S to 35 S RNA occurred with a tm of 56 degree C and is consistent with the hypothesis that tRNALys might be involved in joining two 35 S RNA subunits to form the 70 S RNA complex. There was no indication that the association of either tRNAArg or tRNALys influenced the rate or quality of translation of 70 S or 35 S RNA. A decrease in the rate at which 70 S RNA is transcribed occurs in parallel with the dissociation of tRNAArg and tRNALys.

Arginine↗

Human placental lactogen mRNA and its structural genes during pregnancy: quantitation with a complementary DNA.

A complementary DNA (cDNA) strand was transcribed from human placental lactogen (hPL) mRNA. Based on alkaline sucrose gradient centrifugation, the size of the cDNA was about 8 S, which would represent at least 80% of the hPL mRNA. Previously we showed that four to five times more hPL was synthesized in cell-free extracts derived from term as compared to first trimester placentas. Hybridization of the cDNA with RNA derived from placental tissue revealed that there was about four times more hPL mRNA sequences in total RNA from term placenta than in a comparable quantity of total first trimester RNA. Only background hybridization was observed when the cDNA was incubated with RNA prepared from human kidney. To test if this differential accumulation of hPL mRNA was the result of an amplification of hPL genes, we hybridized the labeled cDNA with cellular DNA from first trimester and term placentas and with DNA isolated from human brain. In all cases, the amount of hPL sequences was approximately two copies per haploid genome. Thus, the enhanced synthesis of hPL mRNA appears to result from a transcriptional activation rather than an amplification of the hPL gene. The increase likely reflects placental differentiation in which the proportion of syncytial trophoblast increases at term.

DNA↗

Direct labeling of RNA with multiple biotins allows sensitive expression profiling of acute leukemia class predictor genes.

Direct labeling of RNA is an expedient method for labeling large quantities (e.g. micrograms) of target RNA for microarray analysis. We have developed an efficient labeling system that uses T4 RNA ligase to attach a 3'-biotinylated donor molecule to target RNA. Microarray analyses indicate that directly labeled RNA is uniformly labeled, has higher signal intensity than comparable labeling methods and achieves high transcript detection sensitivity. The labeled donor molecule we have developed allows the attachment of multiple biotins, which increases target signal intensity up to 30%. We have used this direct-labeling method to detect previously discovered class predictor genes for two types of cancer: acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). In order to test the sensitivity of direct RNA labeling, we analyzed the AML and ALL expression profiles for predictor genes that were previously found to show elevated expression in the disease state. Direct labeling of AML poly(A) RNA detects 90% of the class predictor genes that are detected by the IVT-based target amplification method used to discover the genes. These results indicate that the detection sensitivity, simplicity (single tube reaction) and speed (2 h) of this direct labeling protocol may be ideal for diagnostic applications that do not require target amplification.

Acute Disease↗

Cervical shedding of HIV-1 RNA among women with low levels of viremia while receiving highly active antiretroviral therapy.

BACKGROUND: Among women with low or undetectable quantities of HIV-1 RNA in plasma, factors associated with genital HIV-1 RNA shedding, including choice of treatment regimen, are poorly characterized. METHODS: We measured HIV-1 RNA in cervical swab specimens obtained from participants in the Women's Interagency HIV Study who had concurrent plasma viral RNA levels <500 copies/mL, and we assessed factors associated with genital HIV shedding. The study was powered to determine the relative effects of antiretroviral protease inhibitors (PIs) versus nonnucleoside reverse transcriptase inhibitors (NNRTIs) on viral RNA shedding. RESULTS: Overall, 44 (15%) of 290 women had detectable HIV-1 RNA in cervical specimens. In the final multivariate model, shedding was independently associated with NNRTI (vs. PI) use (odds ratio [OR], 95% confidence interval [CI]: 2.24, 1.13 to 4.45) and illicit drug use (OR, 95% CI: 2.41, 0.96 to 5.69). CONCLUSIONS: This is the largest study to define risks for genital HIV-1 RNA shedding in women with low/undetectable plasma virus. Shedding in this population was common, and NNRTI-based highly active antiretroviral therapy (HAART) (vs. PI-based HAART) was associated with genital HIV shedding. Further study is required to determine the impact of these findings on transmission of HIV from mother to child or to sexual partners.

Adult↗

[Influence of dexamethasone on RNA synthesis in human peripheral blood lymphocytes].

Biphasic character of dexamethasone action on the lymphoid tissue is observed in the tissue culture of partially purified peripheral blood lymphocytes. Stimulation of the RNA synthesis occurred after 6-hour incubation of lymphocytes with the hormone. Sedimentation analysis of labeled RNA, fractionated in a column containing poly-U sepharose pointed to increase in the quantity of the messenger RNA and enrichment of the cytoplasmic RNA with poly-A sequences. At the same time the Mn++-dependable RNA polymerase sensitive to alpha-amanitin was activated. Inhibition of the RNA synthesis is observed after 24-hour cultivation of lymphocytes with the hormone. Biphasic effect of the steroid is also seen in the reaction of rosetteformation.

DNA-Directed RNA Polymerases↗

Increased density of class I major histocompatibility complex antigens and decreased density of T-cell differentiation antigens in the early stages of T-cell activation.

Major histocompatibility complex (MHC) antigens and T-cell differentiation antigens on activated T cells play a central role in T-cell interactions. In the present study, we have analyzed time courses of both quantity and density of the T-cell differentiation antigens, CD3 (T3), CD4 (T4), and CD8 (T8), as well as MHC antigens, on the cell surface of T cells, and made correlated measurements of DNA content with the surface antigen quantity as well with RNA content and cell size following activation of T cells by phytohemagglutinin. We found that the quantity and density of class I MHC antigens increase within 24 hr following activation and then decrease, while the quantity and density of the T-cell differentiation antigens decrease within 24 hr following activation, which suggests that T-cell recognition involving class I MHC gene products occurs at an early stage of T-cell activation. Class II MHC antigens can be detected on more than 40% of T cells as the expression of the T-cell differentiation antigens increases much later in the response. Cell cycle studies demonstrated that the density of class I MHC, CD3, CD4, and CD8 antigens was greater in G0/G1 phase cells than G2 phase cells at all times tested during T-cell activation. Our findings suggest that T cells demonstrate a differential regulation in expression of MHC and T-cell differentiation antigens following activation which may reflect their role in cellular interactions.

Antigens, Differentiation, T-Lymphocyte↗

Regulation of synthesis of the larval serum proteins of Drosophila melanogaster.

We have determined the relative amounts of subunits of larval serum proteins (LSPs) 1 and 2 during larval development in Drosophila melanogaster. These results indicate that synthesis of polypeptide subunits of LSP-1 and LSP-2 is coordinate: the proteins are first detected at the same time; they accumulate in a coordinate fashion; their RNAs are first detected at the same time; the RNAs also accumulate in similar relative amounts. Analyses of fat body polypeptides and fat body RNA indicate that synthesis of LSP-1 declines at a time when there are still substantial quantities of LSP-1 RNA in the cytoplasm. Cessation of LSP-1 subunit synthesis occurs before cessation of LSP-2 synthesis, indicating that at late times the genes (or mRNAs) for these two proteins are subject to different "switch-off" controls.

Adipose Tissue↗

Detection of hepatitis C virus specific core protein in serum of patients by a sensitive fluorescence enzyme immunoassay (FEIA).

A protein-capture fluorescence enzyme immunoassay (FEIA) was developed using monoclonal antibodies (mAbs) against recombinant hepatitis C virus (HCV) core protein. Four hybridoma cell lines (5E3, 5F11, 515S, 1080S) were established and characterized. These monoclonal antibodies (mAbs) each had IgG1 and OgG2 isotypes, and recognized major B cell epitopes within the immunodominant nucleoprotein amino terminal subregion. Using mAb 5F11 as the first antibody to the solid phase and beta-D-galactosidase-conjugated mAb 5E3 as the second antibody to the protein, we established a specific HCV core protein capturing FEIA capable of detecting as little as 20 pg/ml of recombinant HCV core protein. HCV core protein in serum was detectable after treatment with 4.0% polyethyleneglycol, 0.5 NaOH, and 5% Triton X-100. The results of a peptide inhibition assay indicated that this FEIA is specific for HCV RNA positive sera. The quantity of HCV core protein detected in serum was significantly correlated to the level of HCV RNA. The detection limit for HCV core proteins was an HCV RNA per titer of approximately 10(4)/ml. Using this FEIA system, the detection ratio of HCV core protein in patients with chronic HCV infection was 92.3% (70/76).

Animals↗

5.9-S RNA, a new RNA characterized in several mammalian cell lines.

A new species of RNA has been isolated from several different cell lines, both oncornavirus producing and non-producing. This RNA, which we designate 5.9-S RNA is present in the cellular cytoplasmic fraction at very low concentration (approximately 1% of the quantity of 4-S RNA), but it accumulates to much higher levels in two murine oncornaviruses, Moloney murine sarcoma leukemia virus complex and Gross leukemia virus, where it represents as much as 10% of the low-molecular-weight RNA fraction associated with the 70-S RNA genome. The electrophoretic mobility and fingerprint analysis of T1 RNase digest products show that this species of RNA is approximately 160-165-residues long, and can be unequivocally distinguished from all previously described species of RNA in this size range.

AKR murine leukemia virus↗