Introgression of a quantitative trait locus for yield from Glycine soja into commercial soybean cultivars

The value of exotic germplasm in broadening the genetic base of most crops has been demonstrated many times. However, the difficulties involved in working with exotic germplasm have limited their utility in plant breeding. Unwanted linkages often thwart the successful incorporation of beneficial exotic genes into commercial lines. Thus, the use of exotics in traditional breeding makes the process of crop improvement a tedious, time-consuming and expensive endeavor. The availability of molecular markers makes it possible to isolate specific genomic regions and transfer them into commercial varieties with minimal linkage drag. We found a yield-enhancing quantitative trait locus (QTL) from Glycine soja (Siebold and Zucc.) by evaluating a population of 265 BC(2) individuals from a cross between HS-1 and PI 407305. The yield QTL was located on linkage group B2(U26) of the soybean [Glycine max (L.) Merrill] genetic linkage map. In a 2-year, multi-location study, individuals carrying the PI 407305 haplotype at the QTL locus demonstrated a 9.4% yield advantage over individuals that did not contain the exotic haplotype. When tested in a more uniform "HS-1-like" background in two locations, we observed an 8% yield advantage for lines that carry the PI 407305 haplotype. We further assessed the QTL effect in various elite soybean genetic backgrounds. The yield effect was consistently observed in only two of six genetic backgrounds. Individuals carrying the PI 407305 haplotype at the QTL locus had a 9% yield advantage in yield trials across locations. Despite the limited adaptability of this yield-QTL across genetic backgrounds, this study demonstrates the potential of exotic germplasm for yield enhancement in soybean.

Introgression of a quantitative trait locus for yield from Glycine soja into commercial soybean cultivars

The value of exotic germplasm in broadening the genetic base of most crops has been demonstrated many times. However, the difficulties involved in working with exotic germplasm have limited their utility in plant breeding. Unwanted linkages often thwart the successful incorporation of beneficial exotic genes into commercial lines. Thus, the use of exotics in traditional breeding makes the process of crop improvement a tedious, time-consuming and expensive endeavor. The availability of molecular markers makes it possible to isolate specific genomic regions and transfer them into commercial varieties with minimal linkage drag. We found a yield-enhancing quantitative trait locus (QTL) from Glycine soja (Siebold and Zucc.) by evaluating a population of 265 BC(2) individuals from a cross between HS-1 and PI 407305. The yield QTL was located on linkage group B2(U26) of the soybean [Glycine max (L.) Merrill] genetic linkage map. In a 2-year, multi-location study, individuals carrying the PI 407305 haplotype at the QTL locus demonstrated a 9.4% yield advantage over individuals that did not contain the exotic haplotype. When tested in a more uniform "HS-1-like" background in two locations, we observed an 8% yield advantage for lines that carry the PI 407305 haplotype. We further assessed the QTL effect in various elite soybean genetic backgrounds. The yield effect was consistently observed in only two of six genetic backgrounds. Individuals carrying the PI 407305 haplotype at the QTL locus had a 9% yield advantage in yield trials across locations. Despite the limited adaptability of this yield-QTL across genetic backgrounds, this study demonstrates the potential of exotic germplasm for yield enhancement in soybean.

[Synthesis and bioaction of 2-alkyl-4(1H)-quinolone]

Five quinolone alkaloids (IVa, Va, c, d, g) including two new compounds (IVa, Vc) from Evodia rutaecarpa and nine analogs are synthesized in good yield by using acid-catalyzed condensation of a series of 3-oxoalkkanoic acid esters with aniline and further methylized with methyl iodide. The other analogue Vh is prepared through the reaction of lithium enolate methyl ketone with N-methylisatoic anhydride. Eight compounds (IVa, d, f; Vb, c, d, f, h) were synthesized for the first time. Pharmacological studies showed that these compounds have vasoconstriction inhibiting and antiulcer effects. Compound IVb also has cytotoxic effect.

In situ spatial patterns of soil bacterial populations, mapped at multiple scales, in an arable soil

Very little is known about the spatial organization of soil microbes across scales that are relevant both to microbial function and to field-based processes. The spatial distributions of microbes and microbially mediated activity have a high intrinsic variability. This can present problems when trying to quantify the effects of disturbance, management practices, or climate change on soil microbial systems and attendant function. A spatial sampling regime was implemented in an arable field. Cores of undisturbed soil were sampled from a 3 x 3 x 0.9 m volume of soil (topsoil and subsoil) and a biological thin section, in which the in situ distribution of bacteria could be quantified, prepared from each core. Geostatistical analysis was used to quantify the nature of spatial structure from micrometers to meters and spatial point pattern analysis to test for deviations from complete spatial randomness of mapped bacteria. Spatial structure in the topsoil was only found at the microscale (micrometers), whereas evidence for nested scales of spatial structure was found in the subsoil (at the microscale, and at the centimeter to meter scale). Geostatistical ranges of spatial structure at the micro scale were greater in the topsoil and tended to decrease with depth in the subsoil. Evidence for spatial aggregation in bacteria was stronger in the topsoil and also decreased with depth in the subsoil, though extremely high degrees of aggregation were found at very short distances in the deep subsoil. The data suggest that factors that regulate the distribution of bacteria in the subsoil operate at two scales, in contrast to one scale in the topsoil, and that bacterial patches are larger and more prevalent in the topsoil.

A constitutive gene expression system derived from the tCUP cryptic promoter elements

A limited number of constitutive promoters have been used to direct transgene expression in plants and they are often derived from non-plant sources. Here, we describe novel gene-regulatory elements which are associated with a cryptic constitutive promoter from tobacco, tCUP, and modifications that were made to create a strong gene-expression system that is effective across all living cell types from a wide range of plant species, including several important crops ( Arabidopsis, canola, flax, alfalfa, tobacco). The tCUP 5' untranslated region was mutated to eliminate translational interference by upstream ATGs, and the influence of the Kozak consensus sequence on the levels of a beta-glucuronidase (GUS) reporter gene activity was demonstrated. These modifications resulted in expression that was greatly enhanced in all organs. A TATA consensus sequence was added to the core promoter to complement an existing Initiator (Inr) sequence. Although this addition was known to elevate core promoter activity by 3-fold the additive effect on the overall gene-expression system was marginal in all of the transgenic plants tested. Two transcriptional enhancers were identified and the region containing them were oligomerized, yielding a significant increase in marker gene-expression in some but not all plant species. In general, the enhanced tCUP gene-expression system generated levels of GUS activity which exceeded that of the 35S promoter in most plant species and the elevation in activity occurred uniformly among the various plant organs. The potential benefit of cryptic elements for the construction of gene-expression systems for crop species is discussed

Multidrug-resistance-associated protein MGr1-Ag is identical to the human 37-kDa laminin receptor precursor

We report the isolation and functional characterization of the gene encoding MGr1-Ag, a multidrug-resistance-associated protein. A lambdagt11 cDNA library derived from colorectal carcinoma SW480 cells was screened with monoclonal antibody MGr1. DNA homology analysis of 22 positive clones (designated R1-R22) suggested human 37-kDa laminin receptor precursor (37LRP, R7/R9/R15/R16/R19/R20) and a novel gene (R22) as candidate genes encoding MGr1-Ag. Western blot analysis showed that anti-R20 serum reacted with a unique protein band that was consistent with MGr1-Ag, while anti-R22 serum could not react with MGr1-Ag. The coding gene for MGr1-Ag was amplified using reverse transcription-PCR. Sequence analysis revealed that the MGr1-Ag and 37LRP genes shared the same coding sequence. An in vitro drug sensitivity assay indicated that down-regulation of 37LRP by an antisense technique could significantly enhance the cytotoxicity of anticancer drugs to gastric cancer cells. Thus we draw the conclusion that MGr1-Ag is identical to 37LRP.

[Studies on synthesis and bioactivity of 2-alkenyl-4(1H)-quinolone]

Three 2-alkenyl-4(1H)-quinolone compounds(I-III) were synthesized by two methods. III is a new compound from Evodia rutaecarpa and was synthesized through the reaction of the aldehyde intermediate(5) with Wittig reagent. The other two compounds were synthesized for the first time. These compounds showed vasodilating and antibacteria effects in pharmacological tests.

The immunogenetics and pathogenesis of gastric cancer. Highlights of the First Sino-European Workshop on the Immunogenetics and Pathogenesis of Gastric Cancer

Clinical scientists from eight European countries and China gathered in the ancient Chinese capital of Xi'an on April 26-28, 2001 to discuss collaboration on a modern approach to gastric cancer prevention. Participants at the First Sino-European Workshop on Immunogenetics and Pathogenesis of Gastric Cancer presented their most up-to-date research results on topics ranging from epidemiology and immune mechanisms to Helicobacter pylori and vaccine development. Researchers then formed groups with their Chinese or European counterparts to plan future research endeavors which will benefit Chinese and European populations alike. After 3 years of organization between the Institute of Digestive Diseases of the Fourth Medical University in Xi'an, China and the Laboratory of Immunogenetics, VU University Medical Center in Amsterdam, the first workshop came into being under the joint sponsorship of the Commission of the European Union, National Natural Science Foundation of China and the Institute of Digestive Diseases, Xi'an, China. As gastric cancer is the most prevalent malignant tumor in China, the workshop was of special significance to the Chinese researchers and to the Chinese population in general. During the workshop, presentations on the epidemiology of gastric cancer showed that this disease is in fact common the world over: it is the second most common cancer next to lung cancer and about 1 million new cases were diagnosed in 2000. Three-quarters of the cases of gastric cancer occur in Asia, and approximately 80% of these cases are in China and Japan. Genetic factors and environmental factors such as diet and H. pylori infection play a role in gastric carcinogenesis. As a recognized cause of gastric cancer, H. pylori was the subject of various presentations ranging from immunological studies, molecular analysis of strains and pathogenesis to vaccine development. Specific areas of discussion included bacterial-epithelial interactions in H. pylori infection, epidemiology in China, global distribution of vacA and cagA genotypes, new evidence for host factors, nonsteroidal antiinflammatory drugs and H. pylori as independent risk factor for gastric cancer, new diagnostic techniques for H. pylori using serum levels of pepsinogen I, and autoimmune processes in corpus atrophy. Vaccine development using a variety of strategies against H. pylori was the subject of an entire session of talks. Oral immunization with urease with Escherichia coli heat labile enterotoxin was shown to be safe and immunogenic in humans as a mucosal adjuvant. Results of a study using attenuated Salmonella typhimurium as a vehicle for DNA-mediated immunization in mice were also presented. A final presentation discussed an ongoing trial comparing strain variability in the vacA and cagA gene sequences and disease expression between H. pylori infection in Europe and China. Researchers also discussed the role of IL1 gene family and TNF gene polymorphisms in gastric pathology and various immune mechanisms involved in gastric cancer, such as down-regulation of NF kappa B, IL-1 and IL-1RA, cyclooxygenase signalling, and identification of MGAg antibodies. An interactive discussion followed each presentation and ideas and suggestions were provided. According to specialty, the presenters were then assigned to groups of four or five to make plans for joint research projects. A number of international and Chinese observers were present, including representatives from the European Commission, the World Health Organization and the Chinese National Center for Biotechnology Development, and offered input on the financial feasibility of such projects.

[Multivariate analysis for prognostic predictors in non-small cell lung cancer]

BACKGROUND

To determine the prognostic predictors for non-small cell lung cancer ( NSCLC) with multivariate analysis.

METHODS

From 1981 to 1994, 158 patients with NSCLC had been treated by surgery alone or combined with radiotherapy and/ or chemotherapy . Their clinical characteristics were collected. All histological slides were reviewed to evaluate the histological type, tumor differentiation and vascular and lymphatic vessel invasion. Oncoprotein overexpressions were measured by immunohistochemistry assay ( ABC) , including Pan-ras, c-myc, c-erb B2, EGFR and p53. PCNA was also measured by ABC. The endpoints for prognosis consisted of survival, local control and distant metastasis. They were calculated by Kaplan-Meier method with Log-rank test determining the difference between subgroups. Cox model was used for multivariate analysis. The prognostic index ( PI) was calculated basing on the results of multivariate analysis, then the high risk group was determined by PI.

RESULTS

The overall actual 5-year survival rate was 44%. The unfavorable predictors were late T and N of TNM stage ( P = 0. 025 and < 0. 001) , lymphatic vessel invasion ( P= 0. 002) and multi-oncoprotein overexpression ( P= 0. 018) . The overall median of PI was 1. 71( 0. 23-3. 75) . The patients were divided into three groups: good prognosis group ( 42 cases, PI ≤ 1. 3) , moderate prognosis group ( 63 cases, 1. 3 < PI ≤ 2. 2) and bad prognosis group ( 53 cases, PI > 2. 2) . There was significant difference in survival rate among the three groups ( P < 0. 001) , 5-year survival rate was 77%, 45% and 21%, respectively.

CONCLUSIONS

The unfavorable predictors are late T, late N, lymphatic vessel invasion and multi-oncoprotein overexpression. PI could be used to determine the high risk group in patients with NSCLC.

[Significance of lung perfusion scanning with technetium labeled macroaggregated albumin and pulmonary function assay for diagnosis of early hepatopulmonary syndrome]

OBJECTIVE

To evaluate the values of pulmonary function assay and dynamic pulmonary perfusion imaging with technetium labeled macroaggregated albumin ((99m)TcMAA) in the early diagnosis of hepatopulmonary syndrome (HPS).

METHODS

The pulmonary function assay and (99m)TcMAA scans were performed in 28 patients with HPS, 30 cirrhotic patients (CP) without HPS, and 21 healthy controls (HC).

RESULTS

In the patients with HPS, PaO(2), SaO(2) and diffusion capacity for carbon monoxide of lungs (DLco) was significantly lower than that in CP (P<0.01) and HC (P<0.01), and alveolar-arterial gradient [P((A-a))O(2)] was significantly increased (P<0.001). Results from (99m)TcMAA scans showed that the radionuclides were distributed over the spleen, kidney, liver and brain, and the ratios of arterivenous shunt were significantly higher than that in CP (P<0.001) and NC (P<0.001). In cirrhotic patients, DLco significantly decreased (P<0.05), P((A-a))O(2) and shunt ratios increased (P<0.01 and 0.001).

CONCLUSIONS

Pulmonary function assay and dynamic pulmonary perfusion imaging with (99m)TcMAA are sensitive methods for diagnosis of the early HPS.

[Effects of glutamine on the intestinal failure in rats model of acute necrotizing pancreatitis]

OBJECTIVE

To determine the effects of glutamine (Gln) on the intestinal failure in rats with acute necrotizing pancreatitis (ANP) and its possible mechanisms.

METHODS

Fifty-four Sprague-Dawley rats were randomly divided into 3 groups: sham operation (SO, n = 18), ANP (n = 18), and ANP treated with Gln (ANP + Gln, n = 18). ANP model was induced by injection of 5% sodium taurocholate solution into bilo-pancreatic duct. The therapy was continuously given with amino acid solution by a mini-pump via a central intravenous line. In addition, the ANP + Gin group was received 3% Gln dipeptide solution (equal to 2% Gln) with a dosage of 0.5g x kg(-1) x d(-1). These groups were isocaloric and isonitrogenous. Bacterial cultures from pancreas, mesenteric lymph node (MLN), liver, spleen and ascites were done at 24, 48, 72 h after operation. Endotoxin level in portal vein was determined. Pathologic changes of intestinal mucosa were also studied. Apoptosis of intestinal mucosa was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method. Expressions of insulin-like growth factor 1 (IGF-1), Gln synthetase (GSase) and glutaminase (Glnase) mRNA were assayed by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

At 24, 48, 72h, the positive rate of bacterial culture and the endotoxin concentration were increased significantly in ANP group compared to the SO group (P < 0.05), while Gln could decrease them significantly. Pathologic study showed that the height of mucosal villous in ANP group was lower than that in SO group, indicating the intestinal mucosa became more atrophy. However, the height of mucosal villous in ANP + Gln group was no significantly difference compared to that in SO group, indicated Gln could preserve the mucosa well. Apoptotic index was increased in ANP group and decreased in Gln treated rats. Expressions of IGF-1, GSase, Glnase mRNA were down-regulated in ANP group, but were up-regulated in ANP + Gln group.

CONCLUSIONS

The intestinal barrier function was impaired in ANP. Gln could protect intestinal barrier function. This action was probably related to its enhancement of IGF-1, GSase and Glnase mRNA expressions and its inhibition of intestinal mucosal apoptosis.

Tumor therapy with targeted atomic nanogenerators

A single, high linear energy transfer alpha particle can kill a target cell. We have developed methods to target molecular-sized generators of alpha-emitting isotope cascades to the inside of cancer cells using actinium-225 coupled to internalizing monoclonal antibodies. In vitro, these constructs specifically killed leukemia, lymphoma, breast, ovarian, neuroblastoma, and prostate cancer cells at becquerel (picocurie) levels. Injection of single doses of the constructs at kilobecquerel (nanocurie) levels into mice bearing solid prostate carcinoma or disseminated human lymphoma induced tumor regression and prolonged survival, without toxicity, in a substantial fraction of animals. Nanogenerators targeting a wide variety of cancers may be possible.

[Studies on characteristics of kinetics and metabolic shift of genetically engineered yeast Pichia pastoris in high-density chemostat cultivation]

Kinetics and metabolic shift of DNA recombinant yeast Pichia pastoris was studied in high-density chemostat cultivation in which the glycerol was used as a limited substrate. The experimental results showed that (1) cell optical density (OD600) of Pichia pastoris was linear with its dry cell weight (DCW) and wet cell weight (WCW), and reached 100 OD600 = 128.3 g WCW/L or 100 OD600 = 22.9 g DCW/L; (2) The relationship of specific growth rate (mu) and residual concentration of glycerol is accorded with Monod Equation, to obtain mu = mumax S/(Ks + S), where mumax = 0.366 h-1, Ks = 0.1823 g/L. The maximum cell yield of glycerol substrate YG = 0.54 g/g, growth maintaining coefficient m = 0.0069 g/(g.h), The cell yield of oxygen YX/O2 = 30.96 g/moL, and the optimum theoretical dilution rate Dm = 0.341 h-1 by parameter inference; (3) With specific growth rate (mu) increasing, glycerol metablic flux shifts linearly from glycogenesis and hexosephosphate pathways to glycolysis and tricarboxylic acid cycle pathways on basis of variations of consumption rate of NH3.H2O and respiratory quotient value.

COMT genotype, micronutrients in the folate metabolic pathway and breast cancer risk

Catechol-O-methyltransferase (COMT) catalyzes the O-methylation of catechol estrogens (CEs), using S-adenosylmethionine (SAM) as a methyl donor. Several studies have indicated that the val108met COMT polymorphism, which results in a 3-4-fold decrease in activity, is associated with increased breast cancer risk. Folate, whose intake levels have also been associated with breast cancer risk, and other micronutrients in the folate metabolic pathway influence levels of SAM and S-adenosylhomocysteine (SAH), a COMT inhibitor generated by the demethylation of SAM. Because these micronutrients have been shown to alter SAM and SAH levels, we hypothesized that they could also affect COMT-catalyzed CE methylation. Although measurements of SAM and SAH were not initially collected, a secondary analysis of data from two nested case-control studies was performed to examine whether serum levels of folate, vitamin B12 (B12), pyridoxal 5'-phosphate (PLP), cysteine and homocysteine, in conjunction with COMT genotype, were associated with breast cancer risk. COMT(HH) (high activity COMT homozygote) breast cancer cases had statistically significantly lower levels of homocysteine (P = 0.05) and cysteine (P = 0.04) and higher levels of PLP (P = 0.02) than COMT(HH) controls. In contrast, COMT(LL) (low activity COMT homozygote) cases had higher levels of homocysteine than COMT(LL) controls (P = 0.05). No associations were seen between B12, COMT genotype, and breast cancer risk. An increasing number of COMT(L) alleles was significantly associated with increased breast cancer risk in women with below median levels of folate (P(trend) = 0.05) or above median levels of homocysteine (P(trend) = 0.02). These findings are consistent with a role for certain folate pathway micronutrients in mediating the association between COMT genotype and breast cancer risk.

Association of p53, p16, and vascular endothelial growth factor protein expressions with the prognosis and metastasis of gallbladder cancer

BACKGROUND

Tumor suppressor genes were studied in gallbladder disease including cancer for correlation. VEGF (vascular endothelial growth factor) expression was assessed against Nevin staging and metastasis of gallbladder carcinoma. The importance of p53, p16, and VEGF in gallbladder cancer was estimated.

STUDY DESIGN

Twenty-four gallbladder carcinomas, 20 gallbladder adenomas, and 18 chronic cholecystitis specimens were immunohistochemically and histopathologically investigated for the relation of p53, p16, and VEGF to Nevin staging and pathologic grading.

RESULTS

The expression rate of abnormal p53 in gallbladder carcinomas was significantly higher than that in gallbladder adenoma and chronic cholecystitis (p = 0.003, p = 0.014). The expression rate of abnormal p53 in Nevin staging S1, S2, S3 gallbladder carcinoma was significantly higher than that in S4, S5 (p = 0.01). Abnormal p16 was highest in carcinoma, next in adenoma, and lowest in chronic cholecystitis (p = 0.031, p = 0.017). Gallbladder carcinoma expressed VEGF far more often than adenoma or cholecystitis (p = 0.001); VEGF-positive rates were lower in S1, S2, S3 than S4, S5 by Nevin staging of gallbladder cancer (p = 0.044).

CONCLUSION

Mutation of p53 and p16 genes might correlate with progression of of gallbladder carcinoma. Analysis of p53 and p16 can estimate the prognosis of gallbladder cancer. VEGF expression correlates with Nevin staging in gallbladder cancer.

1H and (17)O NMR detection of a lanthanide-bound water molecule at ambient temperatures in pure water as solvent

Lanthanide complexes of a tetra-amide derivative of DOTA (structure 4 in text) with four extended carboxymethyl esters have been characterized by X-ray crystallography and multinuclear NMR spectroscopy. [Eu(4)(H(2)O)](triflate)(3) crystallized from water in the monoclinic, P(21/)(c) space group (a = 10.366 A, b = 22.504 A, c = 23.975 A, and beta = 97.05 degrees ). The Eu(3+) cation is bound to four macrocyclic nitrogen atoms (mean Eu-N = 2.627 A) and four amide oxygen atoms (mean Eu-O(amide) = 2.335 A) in a square antiprismatic geometry with a twist angle of 38.5 degrees between the N4 and O4 planes. A single bound water molecule (Eu-O(W) = 2.414 A) occupies a typical monocapped position on the O4 surface. In pure water, resonances corresponding to a single Eu(3+)-bound water molecule were observed in the (1)H (53 ppm) and (17)O (-897 ppm) NMR spectra of [Eu(4)(H(2)O)](triflate)(3) at 25 degrees C. A fit of the temperature-dependent Eu(3+)-bound (1)H and (17)O water resonance line widths in acetonitrile-d(3) (containing 4% v/v (17)O enriched water) gave identical lifetimes (tau(m)(298)) of 789 +/- 50 micros (in water as solvent; a line shape analysis of the Eu(3+)-bound water resonance gave a tau(m)(298) = 382 +/- 5 micros). Slow water exchange was also evidenced by the water proton relaxivity of Gd(4) (R(1) = 2.2 mM(-1) s(-1), a value characteristic of pure outer-sphere relaxation at 25 degrees C). With increasing temperature, the inner-sphere contribution gradually increased due to accelerated chemical exchange between bound water and bulk water protons. A fitting of the relaxation data (T(1)) to standard SBM theory gave a water proton lifetime (tau(m)(298)) of 159 micros, somewhat shorter than the value determined by high-resolution (1)H and (17)O NMR of Eu(4). Exchange of the bound water protons in Gd(4) with bulk water protons was catalyzed by addition of exogenous phosphate at 25 degrees C (R(1) increased to 10.0 mM(-1) s(-1) in the presence of 1500-fold excess HPO(4)(2-)).

Activation of nuclear factor-kappa b transcriptional activity in airway epithelial cells by thioredoxin but not by N-acetyl-cysteine and glutathione

Increasing evidence indicates that intracellular redox status modulates the activity of various transcriptional factors, including nuclear factor (NF)-kappa B and activator protein-1. Our laboratory has been interested in characterizing the role thioredoxin (TRX) plays in regulating cellular redox status in airway epithelium. TRX is a small, ubiquitous protein with two redox-active half-cysteine residues, -Cys-Gly-Pro-Cys, in its active center. Using primary passage-1 human tracheobronchial epithelial cell cultures and an immortalized human bronchial epithelial cell line, HBE1, we observed that tumor necrosis factor (TNF)-alpha enhanced NF-kappa B transcriptional activity. This observation was based on gel mobility shift assays and interleukin (IL)-8 promoter-reporter gene transfection studies. TNF-alpha activation coincided with translocation of NF-kappa B p65 from the cytoplasm to the nucleus. Pretreatment with N-acetyl-cysteine (NAC) (1 to 10 mM) or glutathione (1 to 10 mM) inhibited TNF-alpha-induced activation of NF-kappa B transcriptional activity and IL-8 promoter-mediated reporter gene expression. In contrast, elevated TRX protein levels in cells enhanced TNF-alpha-dependent NF-kappa B transcriptional activity and IL-8 promoter activity. This observation was independent of the manner in which TRX was elevated in cells (e.g., by cotransfection with a FLAG-TRX expression clone, or by direct exposure to commercially available human TRX protein). Localization of TRX protein by anti-TRX antibody indicated an accumulation of TRX protein in the nucleus after TNF-alpha treatment. The nuclear localization phenomenon was different from the major cytosolic accumulation of glutathione and NAC. This is the first known report demonstrating movement of TRX into the nucleus of airway epithelial cells after an inflammatory stress. These results suggest a compartment effect of thiol chemicals in the regulation of redox-dependent transcriptional activity.

Detection of human herpesvirus 8 DNA in acute leukemia patients

OBJECTIVE

To determine the prevalence of human herpesvirus 8 (HHV-8) DNA in acute leukemia (AL) patients.

METHODS

The presence of HHV-8 DNA sequences in peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) from 50 AL patients was examined using polymerase chain reaction (PCR). Nine human hematopoietic cell lines and PBMC from 30 normal donors were also included.

RESULTS

HHV-8 DNA sequences were detected in one case of acute myelogenous leukemia (AML). The specimens from the bone marrow aspirate, peripheral blood and serum of this patient were all positive. None of the normal donors and human hematopoietic cell lines showed evidence of HHV-8 DNA.

CONCLUSION

The results suggest that the prevalence of HHV-8 is low in AL in China.

Expression and function of CD43 and CDw60 on T cells from patients with atopic dermatitis

Signalling via the CD43 and CDw60 epitopes has been reported as providing two novel pathways of T-lymphocyte activation. In Wiskott-Aldrich syndrome, which has atopic eczema-like skin symptoms, there is a defective expression of CD43, while CDw60 is strongly expressed on T cells from rheumatoid arthritis synovial fluid and from psoriatic skin lesions, and on blood mononuclear cells from patients with cutaneous T-cell lymphoma. We therefore studied the expression and function of these phenotypes on peripheral blood mononuclear cells and on CD4+ and CD8+ T-cell subsets from patients with atopic dermatitis. We observed a significant increase in the percentage of CD43+ cells among the blood mononuclear cells in patients with atopic dermatitis and an enhanced proliferation of CD4+ T cells following stimulation with anti-CD43 antibody. There were no changes in the CDw60 expression or function after stimulation with anti-CDw60 antibody. Thus, CD43 expression was not decreased but rather increased in blood mononuclear cells from patients with atopic dermatitis, whereas CDw60 expression did not differ from healthy controls.

Temperature sensitive nop2 alleles defective in synthesis of 25S rRNA and large ribosomal subunits in Saccharomyces cerevisiae

Using molecular genetic techniques, we have generated and characterized six temperature sensitive (ts) alleles of nop2. All failed to support growth at 37 degrees C and one was also formamide sensitive (fs) and failed to grow on media containing 3% formamide. Conditional lethality is not due to rapid turnover of mutant Nop2p proteins at 37 degrees C. Each allele contains between seven and 14 amino acid substitutions and one possesses a nonsense mutation near the C-terminus. Mapping experiments with one allele, nop2-4, revealed that a subset of the amino acid substitutions conferred the ts phenotype and that these mutations have an additive effect. All six mutants exhibited dramatic reductions in levels of 60S ribosome subunits under non-permissive conditions as well as some reduction at permissive temperature. Processing of 27S pre-rRNA to mature 25S rRNA was defective in all six mutants grown under non-permissive conditions. Levels of the 40S ribosomal subunit and 18S rRNA were not significantly affected. Amino acid substitutions in nop2 conditional alleles are discussed in the context of the hypothesis that Nop2p functions both as an RNA methyltransferase and a trans-acting factor in rRNA processing and large ribosomal subunit biogenesis.

Nucleolar protein Nop12p participates in synthesis of 25S rRNA in Saccharomyces cerevisiae

A genetic screen for mutations synthetically lethal with temperature sensitive alleles of nop2 led to the identification of the nucleolar proteins Nop12p and Nop13p in Saccharomyces cerevisiae. NOP12 was identified by complementation of a synthetic lethal growth phenotype in strain YKW35, which contains a single nonsense mutation at codon 359 in an allele termed nop12-1. Database mining revealed that Nop12p was similar to a related protein, Nop13p. Nop12p and Nop13p are not essential for growth and each contains a single canonical RNA recognition motif (RRM). Both share sequence similarity with Nsr1p, a previously identified, non-essential, RRM-containing nucleolar protein. Likely orthologs of Nop12p were identified in Drosophila and Schizosaccharomyces pombe. Deletion of NOP12 resulted in a cold sensitive (cs) growth phenotype at 15 degrees C and slow growth at 20 and 25 degrees C. Growth of a nop12Delta strain at 15 and 20 degrees C resulted in impaired synthesis of 25S rRNA, but not 18S rRNA. A nop13 null strain did not produce an observable growth phenotype under the laboratory conditions examined. Epitope-tagged Nop12p, which complements the cs growth phenotype and restores normal 25S rRNA levels, was localized to the nucleolus by immunofluorescence microscopy. Epitope-tagged Nop13p was distributed primarily in the nucleolus, with a lesser portion localizing to the nucleoplasm. Thus, Nop12p is a novel nucleolar protein required for pre-25S rRNA processing and normal rates of cell growth at low temperatures.

Identification of active site residues in glucosylceramide synthase. A nucleotide-binding catalytic motif conserved with processive beta-glycosyltransferases

Glucosylceramide synthase (GCS) transfers glucose from UDP-Glc to ceramide, catalyzing the first glycosylation step in the formation of higher order glycosphingolipids. The amino acid sequence of GCS was reported to be dissimilar from other proteins, with no identifiable functional domains. We previously identified His-193 of rat GCS as an important residue in UDP-Glc and GCS inhibitor binding; however, little else is known about the GCS active site. Here, we identify key residues of the GCS active site by performing biochemical and site-directed mutagenesis studies of rat GCS expressed in bacteria. First, we found that Cys-207 was the primary residue involved in GCS N-ethylmaleimide sensitivity. Next, we showed by multiple alignment that the region of GCS flanking His-193 and Cys-207 (amino acids 89-278) contains a D1,D2,D3,(Q/R)XXRW motif found in the putative active site of processive beta-glycosyltransferases (e.g. cellulose, chitin, and hyaluronan synthases). Site-directed mutagenesis studies demonstrated that most of the highly conserved residues were essential for GCS activity. We also note that GCS and processive beta-glycosyltransferases are topologically similar, possessing cytosolic active sites, with putative transmembrane domains immediately N-terminal to the conserved domain. These results provide the first extensive information on the GCS active site and show that GCS and processive beta-glycosyltransferases possess a conserved substrate-binding/catalytic domain.