Relaxation-optimised Hartmann–Hahn transfer using a specifically Tailored MOCCA-XY16 mixing sequence for carbonyl–carbonyl correlation spectroscopy in <Superscript>13</Superscript>C direct detection NMR experiments

Isotropic mixing sequences are one of the key methods to achieve efficient coherence transfer. Among them, the MOCCA-XY16, which keeps the magnetization longitudinal for a significant amount of time, is characterised by favourable relaxation properties. We show here that its adapted version is particularly suited for carbonyl–carbonyl correlations in ¹³C direct detection NMR experiments.     

Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas

The geographical distribution of Aedes albopictus in Brazil was updated according tothe data recorded across the country over the last eight years. Countrywide houseindexes (HI) for Ae. albopictus in urban and suburban areas were described for thefirst time using a sample of Brazilian municipalities. This mosquito is currentlypresent in at least 59% of the Brazilian municipalities and in 24 of the 27 federalunits (i.e., 26 states and the Federal District). In 34 Brazilian municipalities, theHI values for Ae. albopictus were higher than those recorded for Ae. aegypti,reaching figures as high as HI = 7.72 in the Southeast Region. Remarks regarding thecurrent range of this mosquito species in the Americas are also presented. NineteenAmerican countries are currently infested and few mainland American countries havenot confirmed the occurrence of Ae. albopictus. The large distribution and highfrequency of Ae. albopictus in the Americas may become a critical factor in thespread of arboviruses like chikungunya in the new world.     

Self-protection of individual CD4+ T cells against R5 HIV-1 infection by the synthesis of anti-viral CCR5 ligands

It is well established that paracrine secretion of anti-viral CCR5 ligands by CD8+ and CD4+ T cells can block the infection of activated CD4+ T cells by R5 and dual-tropic isolates of HIV-1. By contrast, because CD4+ T cells can be infected by HIV-1 and at least some subsets secrete anti-viral CCR5 ligands, it is possible that these ligands protect against HIV-1 via autocrine as well as paracrine pathways. Here we use a model primary CD4+ T cell response in vitro to show that individual CD4+ T cells that secrete anti-viral CCR5 ligands are 'self-protected' against infection with R5 but not X4 strains of HIV-1. This protection is selective for CD4+ T cells that secrete anti-viral CCR5 ligands in that activated CD4+ T cells in the same cultures remain infectable with R5 HIV-1. These data are most consistent with an autocrine pathway of protection in this system and indicate a previously unappreciated selective pressure on the emergence of viral variants and CD4+ T cell phenotypes during HIV-1 infection.     

Hyperspectral Remote Sensing of Canopy Biodiversity in Hawaiian Lowland Rainforests

Mapping biological diversity is a high priority for conservation research, management and policy development, but few studies have provided diversity data at high spatial resolution from remote sensing. We used airborne imaging spectroscopy to map woody vascular plant species richness in lowland tropical forest ecosystems in Hawai’i. Hyperspectral signatures spanning the 400–2,500 nm wavelength range acquired by the NASA Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) were analyzed at 17 forest sites with species richness values ranging from 1 to 17 species per 0.1–0.3 ha. Spatial variation (range) in the shape of the AVIRIS spectra (derivative reflectance) in wavelength regions associated with upper-canopy pigments, water, and nitrogen content were well correlated with species richness across field sites. An analysis of leaf chlorophyll, water, and nitrogen content within and across species suggested that increasing spectral diversity was linked to increasing species richness by way of increasing biochemical diversity. A linear regression analysis showed that species richness was predicted by a combination of four biochemically-distinct wavelength observations centered at 530, 720, 1,201, and 1,523 nm (r ² = 0.85, p < 0.01). This relationship was used to map species richness at approximately 0.1 ha resolution in lowland forest reserves throughout the study region. Future remote sensing studies of biodiversity will benefit from explicitly connecting chemical and physical properties of the organisms to remotely sensed data.     

IL-21 counteracts the regulatory T cell-mediated suppression of human CD4+ T lymphocytes

High expression of IL-21 and/or IL-21R has been described in T cell-mediated inflammatory diseases characterized by defects of counterregulatory mechanisms. CD4(+)CD25(+) regulatory T cells (Treg) are a T cell subset involved in the control of the immune responses. A diminished ability of these cells to inhibit T cell activation has been documented in immune-inflammatory diseases, raising the possibility that inflammatory stimuli can block the regulatory properties of Treg. We therefore examined whether IL-21 controls CD4(+)CD25(+) T cell function. We demonstrate in this study that IL-21 markedly enhances the proliferation of human CD4(+)CD25(-) T cells and counteracts the suppressive activities of CD4(+)CD25(+) T cells on CD4(+)CD25(-) T cells without affecting the percentage of Foxp3(+) cells or survival of Treg. Additionally, CD4(+)CD25(+) T cells induced in the presence of IL-21 maintain the ability to suppress alloresponses. Notably, IL-21 enhances the growth of CD8(+)CD25(-) T cells but does not revert the CD4(+)CD25(+) T cell-mediated suppression of this cell type, indicating that IL-21 makes CD4(+) T cells resistant to suppression rather than inhibiting CD4(+)CD25(+) T cell activity. Finally, we show that IL-2, IL-7, and IL-15, but not IL-21, reverse the anergic phenotype of CD4(+)CD25(+) T cells. Data indicate that IL-21 renders human CD4(+)CD25(-) T cells resistant to Treg-mediated suppression and suggest a novel mechanism by which IL-21 could augment T cell-activated responses in human immune-inflammatory diseases.     

Apolipoprotein [a] genotype influences isoform dominance pattern differently in African Americans and Caucasians

Plasma lipoprotein [a] (Lp[a]) concentrations are inversely associated with, and largely determined by, apolipoprotein [a] (apo[a]) gene size, a highly polymorphic trait. We studied if, within an individual, the smaller apo[a] isoform always dominated, whether there was interaction between the two alleles, and whether these features differed between Caucasians and African Americans. We determined apo[a] gene sizes, apo[a] protein sizes and relative amounts, and plasma Lp[a] levels in 430 individuals (263 Caucasians and 167 African Americans). Of the 397 heterozygotes with at least one detectable apo[a] isoform (238 Caucasians and 159 African Americans), the larger allele dominated in 28% of Caucasians and 23% of African Americans, while the smaller allele dominated in 56% of Caucasians and 45% of African Americans. In Caucasians, dominance of the smaller allele increased with Lp[a] levels, from 44% at Lp[a] < or = 30 nM to 81% at Lp[a] >100 nM (P < 0.0001). Dominance by the smaller allele increased with increasing size of the larger allele in both groups but with the smaller allele only in African Americans. There was no interaction between apo[a] alleles within genotypes; one apo[a] isoform level was not associated with the other isoform level, and isoform levels were not affected by the difference in size. More of the dominance pattern was explained by Lp[a] level and apo[a] genotype in African Americans than in Caucasians (29% vs. 13%). Thus, genotype influences isoform-specific Lp[a] levels and dominance patterns differently in African Americans and in Caucasians.     

Fine mapping of the Autosomal Dominant Split Hand/Split Foot Locus on Chromosome 7, Band q21.3-q22.1

Split hand/split foot (SHFD) is a human developmental defect characterized by missing digits, fusion of remaining digits, and a deep median cleft in the hands and feet. Cytogenetic studies of deletions and translocations associated with this disorder have indicated that an autosomal dominant split hand/split foot locus (gene SHFD1) maps to 7q21-q22. To characterize the SHFD1 locus, somatic cell hybrid lines were constructed from cytogenetically abnormal individuals with SHFD. Molecular analysis resulted in the localization of 93 DNA markers to one of 10 intervals surrounding the SHFD1 locus. The translocation breakpoints in four SHFD patients were encompassed by the smallest region of overlap among the SHFD-associated deletions. The order of DNA markers in the SHFD1 critical region has been defined as PON–D7S812–SHFD1–D7S811–ASNS. One DNA marker, D7S811, detected altered restriction enzyme fragments in three patients with translocations when examined by pulsed-field gel electro-phoresis (PFGE). These data map SHFD1, a gene that is crucial for human limb differentiation, to a small interval in the q21.3-q22.1 region of human chromosome 7.     

The use of cyprinodont fish, Aphanius fasciatus, as a sentinel organism to detect complex genotoxic mixtures in the coastal lagoon ecosystem

In the present work we aimed to standardise the alkaline comet assay with erythrocytes of the cyprinodont, Mediterranean Killifish, Aphanius fasciatus. The aims of the study were to explore the suitability of this fish to assess biomarkers of genotoxic effects and as a sentinel organism to detect complex genotoxic mixtures in coastal lagoon ecosystems. Following proper optimisation, the application and effectiveness of the comet assay in erythrocytes of A. fasciatus were tested by measuring the tail DNA (%) induced by (a) in vivo exposure of individual fish to X-rays (dose, 3Gy) and (b) following in vitro challenge of erythrocytes with restriction endonucleases Fok-I and Eco-RI, which selectively induce double-strand breaks with cohesive and blunt termini, respectively. Furthermore, in order to evaluate whether circulating fish blood contained actively proliferating cells that could influence the extent of DNA damage in control (untreated) fish, we measured the number of "comets" positive for 5-bromo-2'-deoxyuridine (BrdU) by the use of anti-BrdU antibody and immuno-histochemical methods. Both treatments (i.e. with X-rays and restriction endonucleases) induced statistically significant increases in tail DNA (%) values compared with the relevant untreated controls, indicating the effectiveness of the comet assay in the erythrocytes of A. fasciatus to detect different types of DNA lesions. Results from anti-BrdU antibody labelling of erythrocytes indicated a very low percentage (5%) of "comets" positive for BrdU. Following optimisation and validation of the assay under laboratory conditions, fish were collected in the Orbetello lagoon (Tuscany, Italy), considered to be a significantly polluted site. The results showed statistically significant increases for tail DNA (%) compared with corresponding values observed in erythrocytes of fish caught in the unpolluted reference site "Saline di Tarquinia". The effects of physico-chemical parameters of the water (i.e., salinity, pH and oxygen content) did not significantly influence the induction of DNA damage. These results indicate that the comet assay provides a reliable parameter and that A. fasciatus is a promising "sentinel organism" to detect the genotoxic impact of complex mixtures in coastal lagoon ecosystems.