Long term intrinsic cycling in human life course antibody responses to influenza A(H3N2): an observational and modeling study.

Background: Over a life course, human adaptive immunity to antigenically mutable pathogens exhibits competitive and facilitative interactions. We hypothesize that such interactions may lead to cyclic dynamics in immune responses over a lifetime. Methods: To investigate the cyclic behavior, we analyzed hemagglutination inhibition titers against 21 historical influenza A(H3N2) strains spanning 47 years from a cohort in Guangzhou, China, and applied Fourier spectrum analysis. To investigate possible biological mechanisms, we simulated individual antibody profiles encompassing known feedbacks and interactions due to generally recognized immunological mechanisms. Results: We demonstrated a long-term periodicity (about 24 years) in individual antibody responses. The reported cycles were robust to analytic and sampling approaches. Simulations suggested that individual-level cross-reaction between antigenically similar strains likely explains the reported cycle. We showed that the reported cycles are predictable at both individual and birth cohort level and that cohorts show a diversity of phases of these cycles. Phase of cycle was associated with the risk of seroconversion to circulating strains, after accounting for age and pre-existing titers of the circulating strains. Conclusions: Our findings reveal the existence of long-term periodicities in individual antibody responses to A(H3N2). We hypothesize that these cycles are driven by preexisting antibody responses blunting responses to antigenically similar pathogens (by preventing infection and/or robust antibody responses upon infection), leading to reductions in antigen-specific responses over time until individual's increasing risk leads to an infection with an antigenically distant enough virus to generate a robust immune response. These findings could help disentangle cohort effects from individual-level exposure histories, improve our understanding of observed heterogeneous antibody responses to immunizations, and inform targeted vaccine strategy. Funding: This study was supported by grants from the NIH R56AG048075 (DATC, JL), NIH R01AI114703 (DATC, BY), the Wellcome Trust 200861/Z/16/Z (SR), and 200187/Z/15/Z (SR). This work was also supported by research grants from Guangdong Government HZQB-KCZYZ-2021014 and 2019B121205009 (YG and HZ). DATC, JMR and SR acknowledge support from the National Institutes of Health Fogarty Institute (R01TW0008246). JMR acknowledges support from the Medical Research Council (MR/S004793/1) and the Engineering and Physical Sciences Research Council (EP/N014499/1). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

[Atorvastatin inhibits malignant behaviors and induces apoptosis in human glioma cells by up-regulating miR-146a and inhibiting the PI3K/Akt signaling pathway].

OBJECTIVE: To explore the effect of atorvastatin (AVT) on biological behaviors and the miR-146a/PI3K/Akt signaling pathway in human glioma cells. METHODS: Human glioma U251 cells were treated with 8.0 µmol/L AVT or transfected with a miR-146a inhibitor or a negative control fragment (miR-146a NC) prior to AVT treatment. RT-PCR was used to detect miR-146a expression in the cells, and the changes in cell proliferation rate, apoptosis, cell invasion and migration were detected using MTT assay, flow cytometry, and Transwell assay. Western blotting was performed to detect the changes in cellular expressions of proteins in the PI3K/Akt signaling pathway. RESULTS: AVT treatment for 48 h resulted in significantly increased miR-146a expression and cell apoptosis (P < 0.01) and obviously lowered the cell proliferation rate, invasion index, migration index, and expressions of p-PI3K and p-Akt protein in U251 cells (P < 0.01). Compared with AVT treatment alone, transfection with miR-146a inhibitor prior to AVT treatment significantly reduced miR-146a expression and cell apoptosis (P < 0.01), increased the cell proliferation rate, promoted cell invasion and migration, and enhanced the expressions of p-PI3K and p-Akt proteins in the cells (P < 0.01); these effects were not observed following transfection with miR-146a NC group (P>0.05). CONCLUSION: AVT can inhibit the proliferation, invasion and migration and promote apoptosis of human glioma cells possibly by up-regulating miR-146a expression and inhibiting the PI3K/Akt signaling pathway.

Discriminatory performance of adiponectin and leptin in the identification of impaired glucose tolerance: The Guangzhou Biobank Cohort Study - Cardiovascular Disease Subcohort.

BACKGROUND: To evaluate the additional discriminatory performance of adiponectin, leptin, and their ratio in the identification of impaired glucose tolerance (IGT) in men and women without diabetes on top of conventional risk factors. METHODS & RESULTS: A total of 698 subjects underwent an oral glucose tolerance test (oGTT) and adipocytokine measurements. A comprehensive stepwise selection procedure was performed, followed by c-statistics and integrated discrimination improvement (IDI) analysis. In males, adiponectin levels were significantly lower in the IGT group compared to the non-IGT group (Whitney U test, p < 10-4), whereas leptin levels were significantly higher (p = 0.009) in IGT group. In females, adiponectin and leptin levels were not significantly different between groups (Mann-Whitney U test, p = 0.073 and p = 0.08, respectively). Adjusting for the most informative, sex-specific, clinical and biochemical factors, adiponectin, leptin and their ratio were not found to be significant predictors of the response to the glucose load, when modelled as continuous terms or tertiles. In males, the area-under-the-curve (AUC) for adiponectin was estimated at 0.620 (95% CI: 0.558-0.682) and the addition of adiponectin into the basic model provided a ΔAUC benefit of 0.004, showing no additional discriminatory benefit on top of conventional risk factors (IDI p-value: 0.27), nor did the addition of leptin or their ratio. The results were similar in females. CONCLUSIONS: In Chinese individuals without diabetes, no significant evidence for the potential discriminatory value of adiponectin, leptin or their ratio in the identification of IGT on top of conventional risk factors was observed.

Long-term consumption of a Mediterranean diet improves postprandial lipemia in patients with type 2 diabetes: the Cordioprev randomized trial.

Background: Patients with type 2 diabetes (T2D) have an elevated postprandial lipemia (PPL) that has been associated with increased cardiovascular risk. Objective: We aimed to analyze whether the long-term consumption of 2 healthy dietary patterns is associated with an improvement in PPL and remnant cholesterol (RC) concentrations in patients with T2D. Design: We selected patients from the Cordioprev study who underwent oral fat load tests (FLTs) at baseline and the 3-y follow-up (241 patients with and 316 patients without T2D). Subjects were randomly assigned to receive either a Mediterranean diet rich in olive oil (MedDiet; 35% of calories from fat [22% monounsaturated fatty acids (MUFAs)] and 50% from carbohydrates) or a low-fat (LF) diet [<30% fat (12-14% MUFAs) and 55% of calories from carbohydrates]. Lipids were measured in serial bloods drawn at 0, 1, 2, 3, and 4 h after the FLT. Results: After 3 y of dietary intervention, patients with T2D showed an improvement in their PPL measured as postprandial triglycerides (TGs) (P < 0.0001), TG area under the curve (AUC) (P = 0.001), and TG-rich lipoproteins (TRLs-TG; P = 0.001) compared with baseline. Subgroup analysis, based on the type of dietary intervention, showed that those T2D patients randomly assigned to the MedDiet presented a reduction in the TG AUC of 17.3% compared with baseline (P = 0.003). However, there were no differences for T2D patients randomly assigned to the LF diet (P > 0.05) or in patients without T2D (P > 0.05) regardless of the dietary intervention. In addition, the MedDiet induced a significant improvement in the RC AUC in patients with T2D (P = 0.04). However, there was no significant improvement in those following the LF diet. Conclusions: Our findings show that the long-term consumption of a MedDiet rich in olive oil improves PPL and RC concentrations mainly in patients with T2D. This trial was registered at clinicaltrials.gov as NCT00924937.

Glycated Hemoglobin, Albuminuria and Surrogate Markers of Macrovascular Disease in Adults Without Diabetes: The Guangzhou Biobank Cohort Study, Cardiovascular Disease Subcohort.

OBJECTIVES: To explore the clinical utility of glycated hemoglobin (A1C) levels as an early marker of albuminuria, macrovascular disease and subclinical cardiovascular disease in comparison to fasting and postprandial glucose levels in a well-characterized Chinese population with no history of diabetes. METHODS: The study population consisted of 1223 individuals who were enrolled in the Guangzhou Biobank Cohort Study, Cardiovascular Disease Subcohort, and who had undergone oral glucose tolerance tests. The associations between each glycemic measure and albuminuria, carotid intima-media thickness (CIMT) and CIMT-based presence of carotid plaques and aortic arch calcification were assessed by chest radiographs. RESULTS: The overall prevalence of albuminuria, carotid plaque and any aortic arch calcification was 20.6%, 22.8% and 25.8%, respectively. All 3 glycemia indices were significantly associated with albuminuria, but only 1 (fasting glucose) was associated with carotid plaques. No significant difference was detected among them in the area under the curve for albuminuria (chi-square test; p=0.84), carotid plaques (p=0.28) or calcifications (p=0.29). In sensitivity analysis, adjusted for age and sex, the above findings remained unchanged. CONCLUSIONS: Although there was evidence suggesting differential associations, the performance of the glycemic indices was similar, and their association with macrovascular disease and albuminuria was modest.

Associations of the MCM6-rs3754686 proxy for milk intake in Mediterranean and American populations with cardiovascular biomarkers, disease and mortality: Mendelian randomization.

Controversy persists on the association between dairy products, especially milk, and cardiovascular diseases (CVD). Genetic proxies may improve dairy intake estimations, and clarify diet-disease relationships through Mendelian randomization. We meta-analytically (n ≤ 20,089) evaluated associations between a lactase persistence (LP) SNP, the minichromosome maintenance complex component 6 (MCM6)-rs3754686C>T (nonpersistence>persistence), dairy intake, and CVD biomarkers in American (Hispanics, African-American and Whites) and Mediterranean populations. Moreover, we analyzed longitudinal associations with milk, CVD and mortality in PREDIMED), a randomized Mediterranean diet (MedDiet) intervention trial (n = 7185). The MCM6-rs3754686/MCM6-rs309180 (as proxy), LP-allele (T) was strongly associated with higher milk intake, but inconsistently associated with glucose and lipids, and not associated with CVD or total mortality in the whole population. Heterogeneity analyses suggested some sex-specific associations. The T-allele was associated with higher CVD and mortality risk in women but not in men (P-sex interaction:0.005 and 0.032, respectively), mainly in the MedDiet group. However, milk intake was not associated with CVD biomarkers, CVD or mortality either generally or in sub-groups. Although MCM6-rs3754686 is a good milk intake proxy in these populations, attributing its associations with CVD and mortality in Mediterranean women to milk is unwarranted, as other factors limiting the assumption of causality in Mendelian randomization may exist.

Prognostic significance of tumor-associated macrophages density in gastric cancer: a systemic review and meta-analysis.

INTRODUCTION: Tumor-associated macrophages (TAM) play a dual role in the development of gastric cancer (GC). This study aims to analyze the prognostic value of TAM density in GC patients. EVIDENCE ACQUISITION: We conducted a meta-analysis of 11 studies (N.=1043) to investigate the correlation between TAM density and the overall survival (OS) or disease free survival (DFS) of GC patients. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated by the STATA statistical software. EVIDENCE SYNTHESIS: The HR of OS of GC patients with high-density TAM is 1.56 (95% CI: 0.90~2.22, P<0.001) as compared with those with low-density TAM, and that of DFS is 1.10 (95% CI: 0.16~2.03, P=0.022), indicating that TAM density does not significantly predict the poor survival of GC. A subgroup analysis by ethnicity also revealed no significance effect between TAM density and a worse OS among both Asians and Caucasians (Asians: HR=1.47, 95% CI: 0.76~2.18, P<0.001; Caucasians: HR=2.23, 95% CI: 0.62~3.84, P=0.007, respectively). CONCLUSIONS: Our findings provide empirical evidence that TAM density is not an independent predictor for the survival of GC patients.

Genome-wide association study of triglyceride response to a high-fat meal among participants of the NHLBI Genetics of Lipid Lowering Drugs and Diet Network (GOLDN).

OBJECTIVE: The triglyceride (TG) response to a high-fat meal (postprandial lipemia, PPL) affects cardiovascular disease risk and is influenced by genes and environment. Genes involved in lipid metabolism have dominated genetic studies of PPL TG response. We sought to elucidate common genetic variants through a genome-wide association (GWA) study in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN). METHODS: The GOLDN GWAS discovery sample consisted of 872 participants within families of European ancestry. Genotypes for 2,543,887 variants were measured or imputed from HapMap. Replication of our top results was performed in the Heredity and Phenotype Intervention (HAPI) Heart Study (n = 843). PPL TG response phenotypes were constructed from plasma TG measured at baseline (fasting, 0 hour), 3.5 and 6 hours after a high-fat meal, using a random coefficient regression model. Association analyses were adjusted for covariates and principal components, as necessary, in a linear mixed model using the kinship matrix; additional models further adjusted for fasting TG were also performed. Meta-analysis of the discovery and replication studies (n = 1715) was performed on the top SNPs from GOLDN. RESULTS: GOLDN revealed 111 suggestive (p < 1E-05) associations, with two SNPs meeting GWA significance level (p < 5E-08). Of the two significant SNPs, rs964184 demonstrated evidence of replication (p = 1.20E-03) in the HAPI Heart Study and in a joint analysis, was GWA significant (p = 1.26E-09). Rs964184 has been associated with fasting lipids (TG and HDL) and is near ZPR1 (formerly ZNF259), close to the APOA1/C3/A4/A5 cluster. This association was attenuated upon additional adjustment for fasting TG. CONCLUSION: This is the first report of a genome-wide significant association with replication for a novel phenotype, namely PPL TG response. Future investigation into response phenotypes is warranted using pathway analyses, or newer genetic technologies such as metabolomics.

Complete mitochondrial genome sequence of Marmota himalayana (Rodentia: Sciuridae) and phylogenetic analysis within Rodentia.

This is the first report of a complete mitochondrial genome sequence from Himalayan marmot (Marmota himalayana, class Marmota). We determined the M. himalayana mitochondrial (mt) genome sequence by using long-PCR methods and a primer-walking sequencing strategy with genus-specific primers. The complete mt genome of M. himalayana was 16,443 bp in length and comprised 13 protein-coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a typical control region (CR). Gene order and orientation were identical to those in mt genomes of most vertebrates. The heavy strand showed an overall A+T content of 63.49%. AT and GC skews for the mt genome of the M. himalayana were 0.012 and -0.300, respectively, indicating a nucleotide bias against T and G. The control region was 997 bp in size and displayed some unusual features, including absence of repeated motifs and two conserved sequence blocks (CSB2 and CSB3), which is consistent with observations from two other rodent species, Sciurus vulgaris and Myoxus glis. Phylogenetic analysis of complete mt DNA sequences without the control region including 30 taxa of Rodentia was performed with Maximum-Likelihood (ML) and Bayesian Inference (BI) methods and provided strong support for Sciurognathi polyphyly and Hystricognathi monophyly. This analysis also provided evidence that M. himalayana mt DNA was closely related to that from Sciurus vulgaris (Sciuridae) and was similar to mt DNA from Myoxus glis.

Life-course origins of social inequalities in adult immune cell markers of inflammation in a developing southern Chinese population: the Guangzhou Biobank Cohort Study.

BACKGROUND: Socioeconomic position (SEP) throughout life is associated with cardiovascular disease, though the mechanisms linking these two are unclear. It is also unclear whether there are critical periods in the life course when exposure to better socioeconomic conditions confers advantages or whether SEP exposures accumulate across the whole life course. Inflammation may be a mechanism linking socioeconomic position (SEP) with cardiovascular disease. In a large sample of older residents of Guangzhou, in southern China, we examined the association of life course SEP with inflammation. METHODS: In baseline data on 9,981 adults (≥ 50 years old) from the Guangzhou Biobank Cohort Study (2006-08), we used multivariable linear regression and model fit to assess the associations of life course SEP at four stages (childhood, early adult, late adult and current) with white blood, granulocyte and lymphocyte cell counts. RESULTS: A model including SEP at all four life stages best explained the association of life course SEP with white blood and granulocyte cell count for men and women, with early adult SEP (education) making the largest contribution. A critical period model best explained the association of life course SEP with lymphocyte count, with sex-specific associations. Early adult SEP was negatively associated with lymphocytes for women. CONCLUSIONS: Low SEP throughout life may negatively impact late adult immune-inflammatory status. However, some aspects of immune-inflammatory status may be sensitive to earlier exposures, with sex-specific associations. The findings were compatible with the hypothesis that in a developing population, upregulation of the gonadotropic axis with economic development may obscure the normally protective effects of social advantage for men.

Hyperglycaemia and vitamin D: a systematic overview.

Vitamin D plays a role in a range of functions that may impact on glycaemic control. In this study we systematically report on clinical studies evaluating the impact of vitamin D on aspects of hyperglycaemia in non-pregnant adults. A total of 1,294 articles, of which 417 were reviews, were identified. No well-designed randomised, controlled trials were identified that specifically investigated the effects of vitamin D supplementation on glucose and insulin concentrations. The majority of the studies that are available were poorly designed, having limited numbers, short study duration, or were conducted in volunteers with normal baseline, as measured by 25-hydroxyvitamin D (25(OH)D), concentrations or used inadequate doses of the supplements to normalise vitamin D concentrations, or used inappropriate analyses. Most studies did not observe improvements in glycaemia, with few exceptions. The results were more equivocal for aspects of insulin resistance. Most found no benefit on measures of insulin resistance, although some did. However, more studies described improved insulin release, although data from the studies to date are really inadequate to provide any reliable conclusions. Well-conducted randomised, controlled trials with adequate vitamin D doses are required to effectively assess whether this vitamin can reduce the incidence of diabetes.

A systematic review of lifestyle modification and glucose intolerance in the prevention of type 2 diabetes.

Diabetes is reaching epidemic proportions. High risk groups, such as those older individuals or with glucose intolerance have been shown to exhibit a high risk of developing diabetes. We aimed to systematically identify and evaluate those studies that have investigated the impact of lifestyle interventions on the prevention of the development of incident Type 2 diabetes in those with glucose intolerance. Non-pharmacological lifestyle interventions, including manipulation of dietary intakes and physical activity levels are the main approaches taken to reduce the onset of diabetes in high risk groups, such as those with glucose intolerance. Intensive use of each of these lifestyle interventions have been shown to halve the risk of incident diabetes, although less intensive interventions appear to be less effective. Lifestyle modification is a useful weapon in the armoury of preventing the onset of diabetes, which is essential to reduce the associated increased risk of morbidity and mortality that might otherwise overwhelm health care systems in both developed and developing countries.

Sequence and analysis of chromosome 1 of the plant Arabidopsis thaliana.

The genome of the flowering plant Arabidopsis thaliana has five chromosomes. Here we report the sequence of the largest, chromosome 1, in two contigs of around 14.2 and 14.6 megabases. The contigs extend from the telomeres to the centromeric borders, regions rich in transposons, retrotransposons and repetitive elements such as the 180-base-pair repeat. The chromosome represents 25% of the genome and contains about 6,850 open reading frames, 236 transfer RNAs (tRNAs) and 12 small nuclear RNAs. There are two clusters of tRNA genes at different places on the chromosome. One consists of 27 tRNA(Pro) genes and the other contains 27 tandem repeats of tRNA(Tyr)-tRNA(Tyr)-tRNA(Ser) genes. Chromosome 1 contains about 300 gene families with clustered duplications. There are also many repeat elements, representing 8% of the sequence.

Deoxyadenosine analogs induce programmed cell death in chronic lymphocytic leukemia cells by damaging the DNA and by directly affecting the mitochondria.

Adenine deoxynucleosides induce apoptosis in quiescent lymphocytes and are thus useful drugs for the treatment of indolent lymphoproliferative diseases. To explain why deoxyadenosine and its analogs are toxic to a cell that is not undergoing replicative DNA synthesis, several mechanisms have been proposed, including the direct binding of dATP to the pro-apoptotic factor Apaf-1 and the activation of the caspase-9 and -3 pathways. In this study it is shown, by means of several assays on whole cells and isolated mitochondria, that 2-chloro-2'-deoxyadenosine (2CdA) and 2-choloro-2'-ara-fluorodeoxyadenosine (CaFdA) disrupt the integrity of mitochondria from primary chronic lymphocytic leukemia (B-CLL) cells. The nucleoside-induced damage leads to the release of the pro-apoptotic mitochondrial proteins cytochrome c and apoptosis-inducing factor. The other adenine deoxynucleosides tested displayed comparable DNA-damaging potency but did not affect mitochondrial function. Interference with mitochondrial integrity, thus, may be a factor in the potent cytotoxic effects of 2CdA and CaFdA toward nondividing lymphocytes.

Substituted isoquinolines and quinazolines as potential antiinflammatory agents. Synthesis and biological evaluation of inhibitors of tumor necrosis factor alpha.

A series of isoquinolin-1-ones and quinazolin-4-ones and related derivatives were prepared and evaluated for their ability to inhibit tumor necrosis factor alpha (TNFalpha) production in human peripheral blood monocytes stimulated with bacterial lipopolysaccharide (LPS). In an effort to optimize the TNFalpha inhibitory activity, a homologous series of N-alkanoic acid esters was prepared. Several electrophilic and nucleophilic substitutions were also carried out. Alkanoic acid esters of four carbons were found to be optimum for activity in both the isoquinoline and quinazoline series. Ring substituents such as fluoro, bromo, nitro, acetyl, and aminomethyl on the isoquinoline ring resulted in a significant loss of activity. Likewise, similar groups on the quinazoline ring also reduced inhibitory activity. However, the 6- and 7-aminoquinazoline derivatives, 75 and 76, were potent inhibitors, with IC(50) values in the TNFalpha in vitro assay of approximately 5 microM for each. An in vivo mouse model of pulmonary inflammation was then used to evaluate promising candidate compounds identified in the primary in vitro assay. Compound 75 was selected for further study in this inhalation model, and was found to reduce the level of TNFalpha in brochoalveolar lavage fluid of LPS-treated mice by about 50% that of control mice. Thus, compounds such as 75, which can effectively inhibit proinflammatory cytokines such as TNFalpha in clinically relevant animal models of inflammation and fibrosis, may have potential as new antiinflammatory agents. Finally, a quinazoline derivative suitable to serve as a photoaffinity radiolabeled compound was prepared to help identify the putative cellular target(s) for these TNFalpha inhibitors.

Investigation of parvovirus B19 in cardiac tissue from patients with congenital heart disease.

OBJECTIVE: To explore the correlation between human parvovirus B19 (HPV-B19) and congenital heart (CHD) and to investigate the teratogenic effect of HPV-B19. METHODS: A case control study was conducted to investigate the embedded autopsy cardiac tissues of 29 cases of CHD and 30 controls without CHD with nest polymerase chain reaction (PCR). Other viruses, including herpes simplex virus (HSV). Toxoplasma gondii (TOX), cytomegalovirus (CMV) and rubella virus (RV) were also studied in 10 cases of each group with corresponding PCR kits. RESULTS: Five of 29 (17.2%) CHD cases were positive for HPV-B19, while all the 30 controls were negative for HPV-B19 (P=0.0237). All cases studied were negative for both HSV and TOX. Three cases in each group were positive for CMV, with presence of HPV-B19 DNA in 2 cases in the CHD group. Only two cases in the CHD group showed positive reaction for RV. CONCLUSIONS: As far as we know, it is the first report of the presence of HPV-B19 in cardiac tissues of CHD patients. The detection rate of HPV-B19 DNA is significantly different between the two groups, inferring that HPV-B19 might be correlated with CHD.

A New Rosmarinic Acid Derivative from Isodon oresbius.

Phytochemical reinvestigation of ISODON ORESBIUS afforded, in addition to oleanolic acid, ursolic acid, sodoponin, astragalin, and quercetin-3- O-glucoside, three known (oresbiusin A, rosmarinic acid and methyl rosmarinate) and a new rosmarinic acid derivative as well as an ENT-kaurene diterpenoid, neo-angustifolin, characterized as a separated component for the first time. By a combination of 1D- and 2D-NMR techniques the structure of the new compound was established as butyl rosmarinate. The IN VITRO antifungal assay showed that neoangustifolin was active against CANDIDA ALBICANS with the MIC being 50 microg/ml.

Nuclear events in ethylene signaling: a transcriptional cascade mediated by ETHYLENE-INSENSITIVE3 and ETHYLENE-RESPONSE-FACTOR1.

Response to the gaseous plant hormone ethylene in Arabidopsis requires the EIN3/EIL family of nuclear proteins. The biochemical function(s) of EIN3/EIL proteins, however, has remained unknown. In this study, we show that EIN3 and EILs comprise a family of novel sequence-specific DNA-binding proteins that regulate gene expression by binding directly to a primary ethylene response element (PERE) related to the tomato E4-element. Moreover, we identified an immediate target of EIN3, ETHYLENE-RESPONSE-FACTOR1 (ERF1), which contains this element in its promoter. EIN3 is necessary and sufficient for ERF1 expression, and, like EIN3-overexpression in transgenic plants, constitutive expression of ERF1 results in the activation of a variety of ethylene response genes and phenotypes. Evidence is also provided that ERF1 acts downstream of EIN3 and all other components of the ethylene signaling pathway. The results demonstrate that the nuclear proteins EIN3 and ERF1 act sequentially in a cascade of transcriptional regulation initiated by ethylene gas.

Induction of an apoptotic program in cell-free extracts by 2-chloro-2'-deoxyadenosine 5'-triphosphate and cytochrome c.

Adenine deoxynucleosides, such as 2-chloro-2'-deoxyadenosine (2CdA) induce apoptosis in quiescent lymphocytes, and are thus useful drugs for the treatment of indolent lymphoproliferative diseases. However, it has remained puzzling why deoxyadenosine and its analogs are toxic to a cell that is not undergoing replicative DNA synthesis. The present experiments demonstrate that the 5'-triphosphate metabolite of 2CdA (2CdA-5'-triphosphate), similar to dATP, can cooperate with cytochrome c and Apaf-1 to activate caspase-3 in a cell free system. Chronic lymphocytic leukemia cells and normal peripheral blood lymphocytes expressed both caspase-3 and apoptotic protease activating factor 1. Incubation of the lymphocytes with 2CdA induced caspase-3 activation prior to DNA degradation and cell death. Stimulation of the caspase proteolytic cascade by 2CdA-5'-triphosphate, in the context of DNA strand break formation, may provide an explanation for the potent cytotoxic effects of 2CdA toward nondividing lymphocytes.

Activation of the ethylene gas response pathway in Arabidopsis by the nuclear protein ETHYLENE-INSENSITIVE3 and related proteins.

Mutations in the Arabidopsis ETHYLENE-INSENSITIVE3 (EIN3) gene severely limit a plant's response to the gaseous hormone ethylene. ein3 mutants show a loss of ethylene-mediated effects including gene expression, the triple response, cell growth inhibition, and accelerated senescence. EIN3 acts downstream of the histidine kinase ethylene receptor, ETR1, and the Raf-like kinase, CTR1. The EIN3 gene encodes a novel nuclear-localized protein that shares sequence similarity, structural features, and genetic function with three EIN3-LIKE (EIL) proteins. In addition to EIN3, EIL1 orEIL2 were able to complement ein3, suggesting their participation in the ethylene signaling pathway. Overexpression of EIN3 or EIL1 in wild-type or ethylene-insensitive2 plants conferred constitutive ethylene phenotypes, indicating their sufficiency for activation of the pathway in the absence of ethylene.