Colocalization of the gene for nephrogenic diabetes insipidus (DIR) and the vasopressin type 2 receptor gene (AVPR2) in the Xq28 region

The gene for nephrogenic diabetes insipidus (DIR) and the vasopressin type 2 receptor gene (AVPR2) have both been localized in the Xqter region by genetic mapping and functional expression studies, respectively. In this paper genetic evidence that the DIR locus is localized distal to the DXS305 locus and that the functional gene for the V2 receptor is localized between the markers DXS269 and F8 is presented. These further refinements in the localization of both genes strengthen the assumption that both genes are identical and provide a rationale for cloning the gene by reversed genetics strategies.     

N-banding and nucleolus organisers in Asellus aquaticus (Crust. Isop.).

The N-banding technique was used to stain the nucleolus organiser of the karyotype of Asellus aquaticus (crust. Isop.). Observations were made on the morphological expression of nucleolus organisers as secondary constrictions and the presence of nucleoli in mitotic prophase. An attempt was made to correlate the various results and it seems likely that N-banding is not a reflection of NO activity.     

The human gene coding for HCN2, a pacemaker channel of the heart.

Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, underlying 'pacemaker' currents (I(f)/Ih), are involved in pacemaker activity of cardiac sinoatrial node myocytes and central neurons. Several cDNAs deriving from four different genes were recently identified which code for channels characterized by six transmembrane domains and a cyclic nucleotide binding domain. We report here the identification of the human HCN2 gene and show that its functional expression in a human kidney cell line generates a current with properties similar to the native pacemaker f-channel of the heart. The hHCN2 gene maps to the telomeric region of chromosome 19, band p13.3. This is the first identification of a genetic locus coding for an HCN channel.     

Synergistic effect of DAPI and thymidylate stress conditions on the induction of common fragile sites

When supplied to human leukocytes grown in complete medium (RPMI 1640), DAPI, a nonintercalating compound specific for the AT bases of DNA, induces the appearance of three common fragile sites (CFRA) mapped at 1q42, 2q31, and 7p22. The same treatment with DAPI in a medium deficient in folic acid and thymidine (199 M) considerably increases the expression of these sites and induces the appearance of a further 16 CFRA sites at 1q24, 2p25, 4p16, 4q25, 5p15.3, 6p21.3, 6p25, 6q13, 9p24, 16p13.3, 16q23, 17q21, 18q23, 20q13.1, 21q21, and Xq28. The results point to the existence of a synergism between DAPI and thymidylate-stress culture conditions in inducing site-specific chromosome damage. The results also agree with the hypothesis that DAPI-induced CFRA sites are DNA late-replicating chromosomal areas rich in AT bases.     

Functional composition and phenology of fruit-feeding butterflies in a fragmented landscape: variation of seasonality between habitat specialists

For butterflies, tolerance to the matrix may be an important criterion of habitat occurrence in fragmented landscapes. Here we examine the relative effects of habitat fragmentation and the surrounding agricultural matrix on the functional composition of fruit-feeding butterflies of the Atlantic rain forest in southeastern Brazil. Generalized linear models were used to detect the effects of landscape metrics on butterfly richness and abundance of the total assemblage and functional groups. Circular statistics were used to analyze the patterns of monthly abundance of the total assemblage and functional groups in the forest remnants and the surrounding matrices. In total, 650 butterflies representing 57 species were captured; species composition differed significantly between the forest fragments and the surrounding matrices. We recorded 22 forest specialists, 18 matrix specialists, 11 common species with matrix preference and six common species with forest preference. Forest connectivity favored the richness of forest specialists, while habitat fragmentation enhances the richness and abundance of matrix-tolerant species. Circular analysis revealed that forest specialists were more abundant in the rainy season while matrix-tolerant species proliferated in the dry season. Although maintaining connectivity of forest fragments may increase the mobility and dispersion of forest species, our results showed that landscape fragmentation modify butterfly assemblage by promoting an increase of matrix tolerant species with detriment of forest specialists.     

Molecular cytogenetic resources for chromosome 4 and comparative analysis of phylogenetic chromosome IV in great apes

We have generated a panel of 55 somatic cell hybrids retaining fragments of human chromosome 4. Each hybrid has been characterized cytogenetically by FISH and molecularly by 37 STSs, evenly spaced along the chromosome. The panel can be exploited to map subregionally DNA sequences on chromosome 4 and to generate partial chromosome paints useful in the characterization of chromosomal rearrangements involving this chromosome. Furthermore, a panel of 84 YACs mapping on chromosome 4 has been characterized by FISH. A subset of this panel is recognized by STSs used in the somatic cell hybrid characterization. In this way a correlation between the genetic and the physical maps can be established. These resources have been used to investigate the conservation of the phylogenetic chromosome IV in great apes. The results indicate that all the pericentric inversions that differentiate chromosome IV in these species are distinct and that one of the breakpoints frequently lies very close to the centromere. In 4 instances, the YAC containing the breakpoint was identified. The breakpoint in IVq of PTR and MMU lies in the same YAC, suggesting that this breakpoint has been utilized twice in the evolutionary history of this chromosome.     

The bean polygalacturonase-inhibiting protein 2 (PvPGIP2) is highly conserved in common bean (Phaseolus vulgaris L.) germplasm and related species

Polygalacturonase-inhibiting proteins (PGIPs) are extracellular plant protein inhibitors of endo-polygalacturonases (PGs) that belong to the leucine-rich repeat (LRR) protein family. In bean, PGIP is encoded by a small gene family of four members among which Pvpgip2 encodes the most wide-spectrum and efficient inhibitor of fungal PGs. In order to evaluate the sequence polymorphism of Pvpgip2 and its functional significance, we have analyzed a number of wild and cultivated bean (P. vulgaris) accessions of Andean and Mesoamerican origin, and some genotypes from the related species P. coccineus, P. acutifolius, and P. lunatus. Our analyses indicate that the protein encoded by Pvpgip2 is highly conserved in the bean germplasm. The few detected polymorphic sites correspond to synonymous substitutions and only two wild genotypes contain a Pvpgip2 with a single non-synonymous replacement. Sequence comparison showed a slightly larger variation in the related bean species P. coccineus, P. acutifolius, and P. lunatus and confirmed the known phylogenetic relationships with P. vulgaris. The majority of the replacements were within the xxLxLxx region of the leucine rich repeat (LRR) domain and none of them affected residues contributing to structural features. The variant PGIPs were expressed in Nicotiana benthamiana using PVX as vector and their inhibitory activity compared to that of PvPPGIP2. All the variants were able to fully inhibit the four fungal PGs tested with minor differences. Taken together these results support the hypothesis that the overall sequence conservation of PGIP2 and minor variation at specific sites is necessary for high-affinity recognition of different fungal PGs. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

1α,25-Dihydroxyvitamin D3 inhibits CD40L-induced pro-inflammatory and immunomodulatory activity in Human Monocytes

CD40 ligand (CD40L) stimulation induces proinflammatory and immunomodulatory activity in monocytes. Here, we report on the effects of the steroid hormone 1α,25-dihydroxyvitamin D3 (1,25D3) on human blood monocytes that have been stimulated with the CD40L ligand. Co-treatment of CD40L-stimulated monocytes with 1,25D3 resulted in reduced production and secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1β, as well as in reduced expression of the surface co-stimulatory molecules CD80 and CD86. In addition, costimulation of CD4+ T lymphocytes by monocytes co-treated with CD40L and 1,25D3 resulted in reduced cell proliferation and diminished interferon (IFN)-γ but enhanced IL-10 production by CD4+ T cells. Finally, 1,25D3 interfered with the ability of CD40L to rescue monocytes from apoptosis induced by serum withdrawal. These findings suggest that 1,25D3 may regulate the interaction of monocytes with T cells or other cell types that express CD40L, thus influencing the outcome of the immune or inflammatory response.