Nucleotide sequence variation within the human tyrosine kinase B neurotrophin receptor gene: association with antisocial alcohol dependence

To identify sequence variants in genes that may have roles in neuronal responses to alcohol, we resequenced the 5' region of tyrosine kinase B neurotrophin receptor gene (NTRK2) and determined linkage disequilibrium (LD) values, haplotype structure, and performed association analyses using 43 single nucleotide polymorphisms (SNPs) covering the entire NTRK2 region in a Finnish Caucasian sample of 229 alcohol-dependent subjects with antisocial personality disorder (ASPD) and 287 healthy controls. Individually, three SNPs were associated with alcohol dependence and alcohol abuse (AD) (P-value from 0.0019 to 0.0059, significance level was set at P<or=0.01 corrected for multiple testing), whereas a common 18 locus haplotype within the largest LD block of NTRK2, a 119-kb region containing the 5' flanking region and exons 1-15, was marginally overrepresented in control subjects compared to AD individuals (global P=0.057). Taken together, these results support a role for the NTRK2 gene in addiction in a Caucasian population with AD and a subtype of ASPD.

Macrophyte zonation in stormwater wetlands: getting it right! A case study from subtropical Australia

In Australia stormwater wetlands are becoming an increasingly popular component of water sensitive urban design. However, they must be designed to cope with the dynamic nature of urban hydrology, in particular, fluctuations in water level. The concept of macrophyte zonation relies on a thorough understanding of the water regimes of different plant species. Water depth is crucial and the hydroperiod, i.e. duration and frequency of inundation, has a significant impact on the survival of wetland vegetation. The aim of this study was to investigate plant establishment in a newly constructed stormwater wetland in Brisbane, subtropical Australia. Changes in plant distribution and density have been monitored since 2001. Rainfall and water depth data enabled us to use a hydrologic model to predict the extent of inundation of the different macrophytes zones. The field survey showed macrophyte survival was poor with the complete loss of several species in marsh and ephemeral zones. The main reason for the lack of macrophyte establishment and survival was the extended periods of inundation (supported by the hydrologic model) and deeper water levels. Stormwater wetlands must be designed to ensure that ephemeral species are not permanently inundated or the preferred water depths in marsh zones are not exceeded for extended periods.

Molecular assembly of meiotic proteins Asy1 and Zyp1 and pairing promiscuity in rye (Secale cereale L.) and its synaptic mutant sy10

Assembly of two orthologous proteins associated with meiotic chromosome axes in Arabidopsis thaliana (Asy1 and Zyp1) was studied immunologically at meiotic prophase of meiosis of wild-type rye (Secale cereale) and its synaptic mutant sy10, using antibodies derived from A. thaliana. The temporal and spatial expression of the two proteins were similar in wild-type rye, but with one notable difference. Unlike A. thaliana, in which foci of the transverse filament protein Zyp1 appear to linearize commensurately with synapsis, linear tracts of Asy1 and Zyp1 protein form independently at leptotene and early zygotene of rye and coalign into triple structures resembling synaptonemal complexes (SCs) only at later stages of synapsis. The sy10 mutant used in this study also forms spatially separate linear tracts of Asy1 and Zyp1 proteins at leptotene and early zygotene, and these coalign but do not form regular triple structures at midprophase. Electron microscopy of spread axial elements reveals extensive asynapsis with some exchanges of pairing partners. Indiscriminate SCs support nonhomologous chiasma formation at metaphase I, as revealed by multi-color fluorescence in situ hybridization enabling reliable identification of all the chromosomes of the complement. Scrutiny of chiasmate associations of chromosomes at this stage revealed some specificity in the associations of homologous and nonhomologous chromosomes. Inferences about the nature of synapsis in this mutant were drawn from such observations.

A qualitative study of women's views on medical confidentiality

CONTEXT

The need to reinvigorate medical confidentiality protections is recognised as an important objective in building patient trust necessary for successful health outcomes. Little is known about patient understanding and expectations from medical confidentiality.

OBJECTIVE

To identify and describe patient views of medical confidentiality and to assess provisionally the range of these views.

DESIGN

Qualitative study using indepth, open ended face-to-face interviews.

SETTING

Southeastern Pennsylvania and southern New Jersey, USA.

PARTICIPANTS

A total of 85 women interviewed at two clinical sites and three community/research centres.

MAIN OUTCOME MEASURES

Subjects' understanding of medical confidentiality, beliefs about the handling of confidential information and concerns influencing disclosure of information to doctors.

RESULTS

The subjects defined medical confidentiality as the expectation that something done or said would be kept "private" but differed on what information was confidential and the basis and methods for protecting information. Some considered all medical information as confidential and thought confidentiality protections functioned to limit its circulation to medical uses and reimbursement needs. Others defined only sensitive or potentially stigmatising information as confidential. Many of these also defined medical confidentiality as a strict limit prohibiting information release, although some noted that specific permission or urgent need could override this limit.

CONCLUSIONS

Patients share a basic understanding of confidentiality as protection of information, but some might have expectations that are likely not met by current practice nor anticipated by doctors. Doctors should recognise that patients might have their own medical confidentiality models. They should address divergences from current practice and provide support to those who face emotional or practical obstacles to self-revelation.

Strategies for the study of meiosis in rye

We describe how we are furthering our understanding of meiosis in rye (Secale cereale L.) using a combination of cytogenetic and molecular biological approaches. Fluorescent in situ hybridisation, electron microscopy of synaptonemal complexes, sequencing of meiosis-specific genes, and the immunolocalisation of recombinogenic proteins are being combined to build up phenotypic "identikits" of wild type, asynaptic mutants sy1 and sy9, and desynaptic mutant sy10. From this information, we review the status of our current understanding of the genetic control of meiosis in rye, and consider strategies for determining more precisely the interrelationships between meiosis-specific genes and their products.

B chromosomes in hybrids of temperate cereals and grasses

B chromosomes are considered to be genetically inert, yet often have pronounced and surprising effects upon the A chromosome behaviour at meiosis in inter-generic and inter-specific hybrids. We review here our current knowledge of these effects in a number of different hybrids of the temperate cereals and grasses. Through hybridisation, many effects comparable to the pairing control system of wheat are uncovered, together with complex interactions of B chromosomes with hybrid host genotypes. We discuss the genetic and physical basis of the effects and try to make sense of them in terms of what we know about the origin and evolution of B chromosomes in plants.

Unravelling the phylogeny of tetraploid Vicia amoena (Fabaceae) and its diploid relatives using chromosomal landmarks

The chromosomal sites of 5S and 45S rDNA genes were revealed by fluorescence in situ hybridisation, and used as landmarks to resolve the ambiguous taxonomic status of the tetraploid Vicia amoena var. amoena (Fabaceae). Comparisons of the number and location of rDNA loci in V. amoena var. sericea, V. pseudorobus, V. dumetorum, V. pisiformis and V. cracca confirmed that V. amoena var sericea, or a closely related diploid, was a likely progenitor of the tetraploid. However, the tetraploid contains chromosomes bearing rDNA loci which are probably derived from another species, such as V. pseudorobus, suggesting that it is an allotetraploid and the product of an interspecific hybridisation event. This was corroborated by fluorescence in situ hybridisation with genomic DNA from V. amoena var sericea, which not only showed that the tetraploid contains more than one chromosome set, but also that its constituent sets have undergone considerable reorganisation.

Allograft rejection predicts the occurrence of late-onset cytomegalovirus (CMV) disease among CMV-mismatched solid organ transplant patients receiving prophylaxis with oral ganciclovir

The natural history of cytomegalovirus (CMV) disease associated with solid organ transplantation has been modified as a result of the widespread use of antiviral prophylaxis. Anecdotal reports have indicated a reduction of CMV disease at the expense of its later occurrence after completion of ganciclovir prophylaxis. The present study investigated the occurrence of CMV disease and its risk factors among 37 liver and kidney transplant recipients with CMV D+/R- status who received oral ganciclovir during the first 100 days posttransplantation. CMV disease occurred in 9 patients (24.3%) at a median of 144 days posttransplantation (range, 95-190 days). Allograft rejection was found to be strongly associated with the occurrence of late-onset CMV disease (risk ratio, 6.6; 95% confidence interval, 1.4-32.1; P=.02). Thus, CMV D+/R- solid organ transplant recipients receiving 3 months of oral ganciclovir who develop allograft rejection during the period of antiviral prophylaxis may benefit from extended and/or enhanced antiviral prophylaxis to prevent late-onset CMV disease.

Nuclear dispositions of subtelomeric and pericentromeric chromosomal domains during meiosis in asynaptic mutants of rye (Secale cereale L.)

The nuclear dispositions of subtelomeric and pericentromeric domains in pollen mother cells (PMCs) were tracked during meiosis in wildtype and two asynaptic mutants of rye (Secale cereale L.) by means of fluorescence in situ hybridization (FISH). Homozygotes for sy1 and sy9 non-allelic mutations form axial elements during leptotene of male meiosis, but fail to form synaptonemal complexes. Consequently, recombination is severely impaired, and high univalency is observed at metaphase I. Simultaneous FISH with pSc200 subtelomeric tandem repeat and CCS1 centromeric sequence revealed that at pre-meiotic interphase the two domains are in a bipolar Rabl orientation in both the PMCs and tapetal cells. At the onset of meiotic prophase, the subtelomeric regions in PMCs of wildtype and sy9 cluster into a typical bouquet conformation. The timing of this event in rye is comparable with that in wheat, and is earlier than that observed in other organisms, such as maize, yeast and mammals. This arrangement is retained until later in leptotene and zygotene when the pericentromeric domains disperse and the subtelomeric clusters fragment. The mutant phenotype of sy9 manifests itself during leptotene to zygotene, when the pericentromeric regions become distinctly more distended than in wildtype, and largely fail to pair during zygotene. This indicates that difference in the nature or timing of chromosome condensation in this region is the cause or consequence of asynapsis. By contrast, sy1 fails to form comparable aggregates of subtelomeric regions at leptotene in only half of the nuclei studied. Instead, two to five aggregates are formed that fail to disperse at later stages of meiotic prophase. In addition, the pericentromeric regions disperse prematurely at leptotene and do not associate in pairs at any subsequent stage. It is supposed that the sy1 mutation could disrupt the nuclear disposition of centromeres and telomeres at the end of pre-meiotic interphase, which could cause, or contribute to, its asynaptic phenotype.

Molecular cytogenetic analysis of DNA sequences with flanking telomeric repeats in Triticum aestivum cv. Begra

A cloned genomic DNA fragment (pTa241) formerly derived from a DNA fraction obtained from isolated nuclei of embryos of a Polish cultivar of wheat (Triticum aestivum cv. Begra) comprises a tandem repeat of the telomeric array CCCTAAA, and hybridizes in situ exclusively to the telomeres of all chromosome arms of the somatic chromosome complement of wheat. A second cloned fragment (pTa637) derived from the same fraction is 637 bp long, flanked by 28 bp of the same telomeric repeat unit, and hybridizes in situ to the entire lengths of all the chromosomes of the complement. The same pattern of hybridization was observed when the flanking telomeric sequences were removed. A third DNA fragment (pTa1439), derived from unfractionated genomic DNA and flanked with 62 bp of the same telomeric unit, showed the same patterns of distribution. Together with additional evidence from Southern analysis, these observations were interpreted to mean that these sequences are associated with mobile DNA elements and are distributed widely throughout the genome. The chromosomal distribution of the non-telomeric parts of the clones is consistent with the dispersed genomic distribution characteristic of transposons and retroelements.

Retrotransposon evolution in diverse plant genomes

Retrotransposon or retrotransposon-like sequences have been reported to be conserved components of cereal centromeres. Here we show that the published sequences are derived from a single conventional Ty3-gypsy family or a nonautonomous derivative. Both autonomous and nonautonomous elements are likely to have colonized Poaceae centromeres at the time of a common ancestor but have been maintained since by active retrotransposition. The retrotransposon family is also present at a lower copy number in the Arabidopsis genome, where it shows less pronounced localization. The history of the family in the two types of genome provides an interesting contrast between "boom and bust" and persistent evolutionary patterns.

Probing meiosis in hybrids of Lolium (Poaceae) with a discriminatory repetitive genomic sequence

A moderately repetitive genomic DNA sequence (designated pLPBB2-123) derived from Lolium perenne L. (Poaceae) is considerably more abundant in the genome of this species than in that of the closely related L. temulentum. The repetitive sequence probe is clearly able to discriminate between the genomic DNA of both species in Southern analysis, and effectively 'paints' only the chromosome set of L. perenne in diploid and triploid hybrids with L. temulentum. Fluorescence in situ hybridisation of this sequence onto homologous chromosomes during meiosis I of the hybrids shows that the sequence is evenly distributed along all of the chromosomes of L. perenne and appears to have little effect on the structural integrity or recombination potential of hybrid bivalents. Discrimination between chromatin of different parental origin in hybrid bivalents shows for the first time a progressive relaxation of relational coiling of homoeologues throughout meiotic prophase. It also highlights structural irregularities that can now be unequivocally assigned to the longer chromosomes of L. temulentum. The advantages of the use of specific differentially amplified sequences instead of whole genome probes are discussed within the context of introgression breeding programmes within the Lolium/Festuca complex.

Sphingolipids signal heat stress-induced ubiquitin-dependent proteolysis

Sphingolipids are essential eukaryotic membrane lipids that are structurally and metabolically conserved through evolution. Sphingolipids have also been proposed to regulate eukaryotic stress responses as novel second messengers. Here we show that, in Saccharomyces cerevisiae, phytosphingosine, a putative sphingolipid second messenger, mediates heat stress signaling and activates ubiquitin-dependent proteolysis via the endocytosis vacuolar degradation and 26 S proteasome pathways. Inactivation of serine palmitoyltransferase, a key enzyme in generating endogenous phytosphingosine, prevents proteolysis during heat stress. Addition of phytosphingosine bypasses the requirement for serine palmitoyltransferase and restores proteolysis. Phytosphingosine-induced proteolysis requires multiubiquitin chain formation through the stress-responsive lysine 63 residue of ubiquitin. We propose that heat stress increases phytosphingosine and activates ubiquitin-dependent proteolysis.

A new plant assemblage (microfossil and megafossil) from the Lower Old Red Sandstone of the Anglo-Welsh Basin: its implications for the palaeoecology of early terrestrial ecosystems

Lower Old Red Sandstone deposits penetrated by a series of cored boreholes near Newport (South Wales) have been sedimentologically logged, and recovered plant assemblages (microfossil and megafossil) investigated. Sedimentological logging indicates that the deposits are typical of the extensive terrestrial-fluviatile floodplain deposits of the Anglo-Welsh Basin. Palynomorph assemblages have been recovered from a number of horizons and comprise entirely terrestrial forms (spores and phytodebris). They essentially represent a single assemblage, belonging to the middle subzone of the micrornatus-newportensis sporomorph assemblage biozone, and indicate an Early Devonian (mid-Lochkovian) age. The new biostratigraphical data enables correlation with other Lower Old Red Sandstone deposits of the Anglo-Welsh Basin, and the deposits are assigned to the lower part of the St. Maughan's Group. A plant megafossil/mesofossil assemblage recovered from one of the spore-bearing horizons includes a zosterophyll assigned to Zosterophyllum cf. fertile. This is the earliest reported zosterophyll from the Anglo-Welsh Basin. The new palynological/palaeobotanical data provide important information on the palaeoecology and palaeobiogeography of the vegetation of the southeastern margin of the Old Red Sandstone continent during Lochkovian times. Palaeogeographical variation in the distribution of plant microfossils and megafossils is interpreted as reflecting differences between the flora of the lowland floodplain and inland intermontaine basins, although this is to a certain extent overprinted by variation due to localized differences in environmental conditions.

De novo evolution of satellite DNA on the rye B chromosome

The most distinctive region of the rye B chromosome is a subtelomeric domain that contains an exceptional concentration of B-chromosome-specific sequences. At metaphase this domain appears to be the physical counterpart of the subtelomeric heterochromatic regions present on standard rye chromosomes, but its conformation at interphase is less condensed. In this report we show that the two sequence families that have been previously found to make up the bulk of the domain have been assembled from fragments of a variety of sequence elements, giving rise to their ostensibly foreign origin. A single mechanism, probably based on synthesis-dependent strand annealing (SDSA), is responsible for their assembly. We provide evidence for sequential evolution of one family on the B chromosome itself. The extent of these rearrangements and the complexity of the higher-order organization of the B-chromosome-specific families indicate that instability is a property of the domain itself, rather than of any single sequence. Indirect evidence suggests that particular fragments may have been selected to confer different properties on the domain and that rearrangements are frequently selected for their effect on DNA structure. The current organization appears to represent a transient stage in the evolution of a conventional heterochromatic region from complex sequences.

Perillyl alcohol selectively induces G0/G1 arrest and apoptosis in Bcr/Abl-transformed myeloid cell lines

The Bcr/Abl tyrosine kinase that is expressed from the Philadelphia chromosome protects leukemia cells from apoptosis caused by removal of growth factors or by cytotoxic agents and ionizing irradiation. This resistance to apoptosis is associated with a Bcr/Abl-mediated G2/M delay. Therefore, inhibiting Bcr/Abl signaling pathways should block the ability of the Bcr/Abl kinase to protect cells from apoptosis. The monoterpenes, limonene and perillyl alcohol (POH) are new anticancer agents that selectively induce apoptosis in neoplastic cells of a variety of rodent carcinoma models. Since the potential antitumor activities of monoterpenes overlap with signaling pathways affected by the Bcr/Abl kinase, POH and limonene were tested for antileukemia activity. POH, but not limonene selectively induced G0/G1 arrest followed by apoptosis in Bcr/Abl-transformed, but not nontransformed FDC.P1 and 32D myeloid cell lines. In contrast to their greater sensitivity to POH, Bcr/Abl-transformed cells were more resistant than nontransformed cells to several chemotherapy agents and ionizing irradiation. Since in Bcr/Abl-transformed cells, POH induces apoptosis associated with G0/G1 arrest, POH must activate an apoptotic pathway that is not protected by the Bcr/Abl-induced G2/M delay. Monoterpenes may represent novel agents for treating Ph+ leukemias.

Poly-L-lysine improves gene transfer with adenovirus formulated in PLGA microspheres

In vivo gene transfer with recombinant adenovirus vectors can be hindered by the immunogenicity of the adenovirus capsid proteins. Previous work showed that formulation of the vector with biodegradable polymers such as poly-lactic-glycolic acid (PLGA), polyethylene glycol (PEG), or lipids, may shield the virus from inhibition by neutralizing antibodies. Formulation of adenovirus in PLGA microspheres also allowed for extended release in vitro. In experiments described here, we found that the surfactant used in the formation of the primary emulsion could significantly improve the overall yield of virus released. We also tested the effects of adding poly-L-lysine to adenovirus before encapsulation with PLGA. Our results show that although PLL did not effect the yield of virus encapsulated or released from the microspheres, it significantly improved the efficiency of gene transfer after release from the polymer.

Effect of gel re-organization and tensional forces on alpha2beta1 integrin levels in dermal fibroblasts

Mechanical forces are known to play an important role in regulating cell function in a wide range of biological systems. This is of particular relevance to dermal fibroblast function, given that the skin is known to be held under an intrinsic natural tension. To understand more about the generation of force by dermal fibroblasts and their ability to respond to changes in it, we have studied the role of the beta1 integrin receptors expressed by dermal fibroblasts in their ability to generate tensional forces within a collagen type I matrix and the effect of altered tensional force on integrin expression by dermal fibroblasts. Using a purpose-built culture force monitor, function-blocking antibodies directed towards the beta1 receptors dramatically reduced the tensional forces generated by dermal fibroblasts in a 3D collagen I matrix. However, the specific involvement of alpha1 or alpha2 subunits could not be demonstrated. Analysis of cellular response demonstrated that cells isolated from contracting collagen gels expressed fourfold higher levels of alpha2 mRNA than cells isolated from fully restrained gels. The levels of beta1 messenger RNA were relatively unaffected by reductions in force. Cells exposed to single reductions in force, however, did not exhibit alterations in either alpha1 or beta1 mRNA levels. We propose, therefore that alpha2beta1 integrin receptor levels in dermal fibroblasts are not altered in response to single reductions of gel tension, but do change following a continual change in force and associated matrix re-organization

Coordinate upregulation of tenascin C expression with degree of photodamage in human skin

Tenascin C is a large extracellular matrix glycoprotein involved in morphogenesis and wound healing. The distribution and expression levels of tenascin were examined in photodamaged skin to investigate the hypothesis that photoaged skin displays characteristics of wound repair. In situ hybridization and semiquantitative immunohistochemistry were performed on paired skin biopsies from patients with varying levels of photodamage, using monoclonal antibodies and cRNA probes for tenascin and its large isoform. In sun-protected skin, tenascin protein was distributed adjacent to the dermoepidermal junction, usually sparsely and discontinuously; tenascin mRNA was detected in dermal fibroblasts and some keratinocytes. In photodamaged skin, tenascin protein was increased in proportion to the clinical level of photodamage (analysis of variance: P < 0.0001, n = 29). With increased photodamage, tenascin protein expression became continuous along the dermoepidermal junction, extending deeper into and sometimes throughout the papillary dermis; tenascin mRNA was detected throughout the epidermis. Large tenascin isoform protein and mRNA distribution mirrored that of pantenascin, suggesting that it may be the predominant species in photodamaged skin. There was no correlation between tenascin expression levels and age or sex, and no seasonal variation was noted. The results indicate that photodamaged skin demonstrates tenascin increases consistent with an early wound healing response. However, tenascin increases in photodamage appear to be permanent and may therefore interfere with effective repair of ultraviolet-induced damage. In conclusion, this study has shown that dermal tenascin expression increases in proportion to the degree of photodamage. In normal skin, the temporal and spatial patterns of tenascin expression during morphogenesis and tissue remodelling are crucial to their correct progression. In photoageing, the 'normal' control of tenascin expression seems to be abrogated.