Do delta F508 heterozygotes have a selective advantage?

In this paper the fitness of the delta F508 heterozygote is assessed and the age of the delta F508 mutation in the cystic fibrosis locus is estimated. Data from three microsatellite loci are applied. The analysis is performed conditional on the present-day frequency of the delta F508 mutation and based on assumptions about the demographic history of the European population and the mutation rate in the three microsatellite loci. It is shown that the data gives evidence of positive selection (up to 2-3% per delta F508 heterozygote), but also that data could be explained by negative selection of roughly the same order of magnitude. The age of the delta F508 mutation is subsequently estimated; it is found that the mutation is at least 580 generations old, but could be much older depending on the microsatellite mutation rate and the exact number of substitutions experienced in the history of the three microsatellite loci.     

Gamma /delta T cells provide innate immunity against renal cell carcinoma

Host immune function plays a certain role against the development of renal cell carcinomas (RCCs), but the mechanism is not entirely understood. Human gamma/delta (γ/δ) T cells defend the body against infection. In this study, we clarify the role of γ/δ T cells in the surveillance system against RCCs by analyzing the γ/δ T cells in peripheral blood mononucleocytes (PBMs) and tumor infiltrating lymphocytes (TILs) from 41 patients with RCCs. The results showed that the number of γ/δ T cells expressing Vγ2 and Vδ2 in variable elements of TCR was elevated in the PBMs in 10 patients, but not in any of 32 healthy individuals. The proportion of patients with an elevated number of γ/δ T cells (>10%) increased with cancer stage. The level of the γ/δ T cells decreased after surgery. The γ/δ T cells in the TILs were more activated than those in the PBMs. Evaluation of the junctional diversity of TCR Vγ2 and Vδ2 chains showed that the increased peripheral blood γ/δ T cells were oligoclonal rather than polyclonal. Taken together, our findings suggest that γ/δ T cells recognize certain RCC-related antigens and play a role in the surveillance system against RCCs. Received: 30 November 2000 / Accepted: 2 January 2001     

Phosphoinositide 3-kinase delta (PI3Kδ) in leukocyte signaling and function

PI3Kδ is a lipid kinase of the PI3K class IA family involved in early signaling events of leukocytes responding to a wide variety of stimuli. The leukocyte specificity of PI3Kδ is defined by its expression, whereas its signaling function is via the production of phosphoinositide 3,4,5-triphosphates at the proximity of activated receptors for recruiting other signaling molecules. The importance of PI3Kδ in B cell development and function is most apparent, and its role in other leukocyte cell types can be easily demonstrated as well. PI3Kδ participates in the development, activation and migration of T cells and NK cells. The role of PI3Kδ in myeloid cell activities, such as inflammation driven cell infiltration, neutrophil oxidative burst, immune complex mediated macrophage activation, as well as mast cell maturation and degranulation, has been well illustrated in various studies. As a result of the broad effects of PI3Kδ in leukocyte functions, the disruption of PI3Kδ expression or activity leads to decreased inflammatory and immune responses in vivo. The protective role of PI3Kδ inactivation in animal models of arthritis, asthma or obstructive respiratory diseases has been demonstrated. These findings suggest the potential efficacy achievable with PI3Kδ inhibitors in the treatment of autoimmune and respiratory diseases.     

Stabilization of carbon in mineral soils from mangroves of the Sinú river delta,Colombia

Mangrove forests of the Sinú river delta in Cispatá bay, Colombia, show large differences in soil carbon storage between fringe (oceanic) and basin (estuarine) mangroves. We were interested in testing whether these differences in soil carbon are associated with sediment transport processes or whether most of the carbon is produced in situ within the mangrove system. Given past sedimentation dynamics of the Sinú river, we hypothesized that a large portion of soil carbon in basin mangroves is due to sedimentation. We determined total organic carbon content (TOC) as 660.93 ± 259.18 MgC ha^?1 for basin soils up to a sampling depth of 1 m, and as 259 ± 42.61 MgC ha^?1 for fringe soils up to 80 cm depth (maximum soil depth for fringe soils). Using analyses of mineralogy (Al- and Fe-oxides, clay minerals) as well as isotopic analyses of carbon (δ¹³C), the origin of the sediments and their carbon was determined. We found that basin soils in Cispatá bay show similar mineralogical composition than those of fluvial sediments, but the carbon concentration of river sediments was close to zero. Given the large capacity of the Fe and Al oxides in clay minerals to store dissolved carbon, and that the isotopic composition of the carbon is mostly of plant origin, we concluded contrary to our initial hypothesis that the carbon stored in basin mangrove soils are produced in situ. The deposited fluvial sediments do play an important role for carbon storage, but mostly in providing binding surfaces for the stabilization of organic carbon.     

Does butylphenyl-deoxyguanosine triphosphate differentially inhibit DNA polymerase alpha and delta activities in permeabilized HeLa cells?

In eukaryotic cells, two enzymes, DNA polymerases alpha and delta, are thought to play major roles in DNA synthesis. I have used butylphenyl dGTP (BuPdGTP), a potent inhibitor of purified DNA polymerase alpha, to assess the relative activities of these enzymes in two permeabilized cell systems. In both instances BuPdGTP eliminated all of the activity which was sensitive to aphidicolin. However, no conditions were found where BuPdGTP preferentially inhibited the synthesis of Okazaki fragments--the presumed products of DNA polymerase alpha activity. This implies that DNA polymerase activities on the two sides of the replication fork are unable to operate independently, being just two elements of the integrated replication machinery that undertakes DNA synthesis in permeabilized cells.     

Characterization of lung gamma delta T cells following intranasal infection with Mycobacterium bovis bacillus Calmette-Guérin

The lungs are considered to have an impaired capacity to contain infection by pathogenic mycobacteria, even in the presence of effective systemic immunity. In an attempt to understand the underlying cellular mechanisms, we characterized the gammadelta T cell population following intranasal infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG). The peak of gammadelta T cell expansion at 7 days postinfection preceded the 30 day peak of alphabeta T cell expansion and bacterial count. The expanded population of gammadelta T cells in the lungs of BCG-infected mice represents an expansion of the resident Vgamma2 T cell subset as well as an influx of Vgamma1 and of four different Vdelta gene-bearing T cell subsets. The gammadelta T cells in the lungs of BCG-infected mice secreted IFN-gamma following in vitro stimulation with ionomycin and PMA and were cytotoxic against BCG-infected peritoneal macrophages as well as against the uninfected J774 macrophage cell line. The cytotoxicity was selectively blocked by anti-gammadelta TCR mAb and strontium ions, suggesting a granule-exocytosis killing pathway. Depletion of gammadelta T cells by injection of specific mAb had no effect on the subsequent developing CD4 T cell response in the lungs of BCG-infected mice, but significantly reduced cytotoxic activity and IFN-gamma production by lung CD8 T cells. Thus, gammadelta T cells in the lungs might help to control mycobacterial infection in the period between innate and classical adaptive immunity and may also play an important regulatory role in the subsequent onset of alphabeta T lymphocytes.     

Synthesis and binding characteristics of tritiated tipp[Φ], a highly specific and stable delta opioid antagonist

The pseudopeptide H-Tyr-TicΦ[CH₂-NH]Phe-Phe-OH (TIPP[Φ]) is a δ opioid antagonist with high δ receptor affinity and unprecedented δ selectivity. TIPP[Φ] was radiolabelled by catalytic tritiation of its precursor [Tyr(3′,5′-I₂)¹]TIPP[Φ]. The resulting radioligand, [³H]TIPP[Φ], had a specific activity of 1.77 TBq/mmol (47.9 Ci/mmol) and showed high stability against enzymatic degradation. [³H]TIPP[Φ] binding to rat brain membranes was saturable and Scatchard analysis indicated a single binding site with a K_d of 0.98 nM and a B_max of 105.4 fmol/mg. A study of [³H]TIPP[Φ] binding displacement by various receptor-selective opioids showed the expected rank order of potency (δ ⪢ μ > κ). [³H]TIPP[Φ] represents an excellent new radioligand for δ receptor labelling studies in vitro and in vivo.     

阿片受体结构研究的突破性进展—mu,delta,kappa阿片受体全部克隆成功

1993年7月10～15日在瑞典Skovde市召开了1993年国际麻醉性药物研究大会(International Narcotic Research Conference,INRC)。这是20年前召开首届INRC以来一次最激动人心的盛会,会上宣布三类阿片受体(mu,delta,kappa)全部克隆成功。回顾1971年Avram Goldstein首先提出脑细胞膜上存在着立体构型特异性的阿片结合位点,到1973年三个实验室(瑞典的Terenius,美国的Pert & Snyder,以及Simon等)用放射受体分析法论证有阿片受体存在,至今已度过整整20年。从1983年首次克隆出乙酰胆碱N型受体,至今也已过去十年。在此期间先后有十余个实验室致力于纯化或克隆阿片受体。其中     

Novel 6-aryl substituted 4-pyrrolidineaminoquinazoline derivatives as potent phosphoinositide 3-kinase delta (PI3Kδ) inhibitors

In this study, a novel series of 6-aryl substituted 4-pyrrolidineaminoquinazoline derivatives were designed and evaluated as potent PI3Kδ inhibitors. The preliminary SAR was established, and compounds 12d, 20a and 20c displayed leading potent PI3Kδ inhibition, with IC₅₀ values of 4.5, 2.7 and 3.1?nM, respectively, that were comparable to idelalisib (IC₅₀?=?2.7?nM). Moreover, these three compounds showed favorable PI3Kδ isoform selectivity over PI3Kα, PI3Kβ, and PI3Kγ, and showed distinct anti-proliferation profiles against four human B cell lines of Ramos, Raji, RPMI-8226 and SU-DHL-6. In addition, molecular docking simulation showed that several key hydrogen bonding interactions were formed for compounds 12d, 20a and 20c in the PI3Kδ pocket, which might explain their potent PI3Kδ inhibition. These results indicate the 6-aryl substituted 4-pyrrolidineaminoquinazolines were potent PI3Kδ inhibitors.     

Determination of hepatitis delta virus ribozyme N(–1) nucleobase and functional group specificity using internal competition kinetics

Biological catalysis involves interactions distant from the site of chemistry that can position the substrate for reaction. Catalysis of RNA 2′-O-transphosphorylation by the hepatitis delta virus (HDV) ribozyme is sensitive to the identity of the N(–1) nucleotide flanking the reactive phosphoryl group. However, the interactions that affect the conformation of this position, and in turn the 2′O nucleophile, are unclear. Here, we describe the application of multiple substrate internal competition kinetic analyses to understand how the N(–1) nucleobase contributes to HDV catalysis and test the utility of this approach for RNA structure–function studies. Internal competition reactions containing all four substrate sequence variants at the N(–1) position in reactions using ribozyme active site mutations at A77 and A78 were used to test a proposed base-pairing interaction. Mutants A78U, A78G, and A79G retain significant catalytic activity but do not alter the specificity for the N(–1) nucleobase. Effects of nucleobase analog substitutions at N(–1) indicate that U is preferred due to the ability to donate an H-bond in the Watson–Crick face and avoid minor groove steric clash. The results provide information essential for evaluating models of the HDV active site and illustrate multiple substrate kinetic analyses as a practical approach for characterizing structure–function relationships in RNA reactions.     

PI3K delta and PI3K gamma: partners in crime in inflammation in rheumatoid arthritis and beyond?

Dysregulated signal transduction in innate and adaptive immune cells is known to be associated with the development of various autoimmune and inflammatory diseases. Consequently, targeting intracellular signalling of the pro-inflammatory cytokine network heralds hope for the next generation of anti-inflammatory drugs. Phosphoinositide 3-kinases (PI3Ks) generate lipid-based second messengers that control an array of intracellular signalling pathways that are known to have important roles in leukocytes. In light of the recent progress in the development of selective PI3K inhibitors, and the beneficial effects of these inhibitors in models of acute and chronic inflammatory disorders, we discuss the therapeutic potential of blocking PI3K isoforms for the treatment of rheumatoid arthritis and other immune-mediated diseases.     

Distribution of the CCR5delta32 allele (gene variant CCR5) in Rondônia, Western Amazonian region, Brazil

Since around 1723, on the occasion of its initial colonization by Europeans, Rondonia has received successive waves of immigrants. This has been further swelled by individuals from northeastern Brazil, who began entering at the beginning of the twentieth century. The ethnic composition varies across the state according to the various sites of settlement of each wave of immigrants. We analyzed the frequency of the CCR5Δ32 allele of the CCR5 chemokine receptor, which is considered a Caucasian marker, in five sample sets from the population. Four were collected in Porto Velho, the state capital and the site of several waves of migration. Of these, two, from the Hospital de Base were comprised of HB Mothers and HB Newborns presenting allele frequencies of 3.5% and 3.1%, respectively, a third from the peri-urban neighborhoods of Candelária/Bate-Estaca (1.8%), whereas a fourth, from the Research Center on Tropical Medicine/CEPEM (0.6%), was composed of malaria patients under treament. The fifth sample (3.4%) came from the inland Quilombola village of Pedras Negras. Two homozygous individuals (CCR5Δ32/CCR5Δ32) were detected among the HB Mother samples. The frequency of this allele was heterogeneous and higher where the European inflow was more pronounced. The presence of the allele in Pedras Negras revealed European miscegenation in a community largely comprising Quilombolas.     

Changes in the amphipod fauna (crustacea) of the Rhine,Meuse and Scheldt estuary due to the ’delta plan’ coastal engineering works

The amphipod fauna of the delta of the rivers Rhine, Meuse and Scheldt was re-surveyed 30 years after the detailed inventory ofden hartog (1963; 1964). During these 30 years enormous changes have taken place in the morphology and hydrology of this estuarine system. Many habitats were destructed because of the damming of several sea arms. Tidal influence disappeared from a large part of the area or was reduced in other parts. Nearly all indigenous amphipods of the area have suffered severely under these changes. The only species to profit were the recently introducedGammarus tigrinus andCorophium curvispinum. The main causes for the sharp decline of the amphipod fauna are changes in salinity, tidal movements and dike construction.