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Hybridisation
Kinds of Hybridisation Terms modified by Hybridisation Selected AbstractsArtificial chromosome libraries of Streptomyces coelicolor A3(2) and Planobispora rosea,FEMS MICROBIOLOGY LETTERS, Issue 1 2003Rosa Alduina Abstract Using an Escherichia coli,Streptomyces shuttle vector derived from a bacterial artificial chromosome (BAC), we developed methodologies for the construction of BAC libraries of filamentous actinomycetes. Libraries of Streptomyces coelicolor, the model actinomycete, and Planobispora rosea, a genetically intractable strain, were constructed. Both libraries have an average insert size of 60 kb, with maximal insert larger than 150 kb. The S. coelicolor library was evaluated by selected hybridisations to Dra I fragments and by end sequencing of a few clones. Hybridisation of the P. rosea library to selected probes indicates a good representation of the P. rosea genome and that the library can be used to facilitate the genomic analysis of this actinomycete. [source] Morphological evolution in sea urchin development: hybrids provide insights into the pace of evolutionBIOESSAYS, Issue 4 2004Maria Byrne Hybridisations between related species with divergent ontogenies can provide insights into the bases for evolutionary change in development. One example of such hybridisations involves sea urchin species that exhibit either standard larval (pluteal) stages or those that develop directly from embryo to adult without an intervening feeding larval stage. In such crosses, pluteal features were found to be restored in fertilisations of the eggs of some direct developing sea urchins (Heliocidaris erythrogramma) with the sperm of closely (Heliocidaris tuberculata) and distantly (Pseudoboletia maculata) related species with feeding larvae. Such results can be argued to support the punctuated equilibrium model,conservation in pluteal regulatory systems and a comparatively rapid switch to direct development in evolution.1,2 Generation of hybrids between distantly related direct developers may, however, indicate evolutionary convergence. The ,rescue' of pluteal features by paternal genomes may require maternal factors from H. erythrogramma because the larva of this species has pluteal features. In contrast, pluteal features were not restored in hybridisations with the eggs of Holopneustes purpurescens, which lacks pluteal features. How much of pluteal development can be lost before it cannot be rescued in such crosses? The answer awaits hybridisations among indirect and direct developing sea urchins differing in developmental phenotype, in parallel with investigations of the genetic programs involved. BioEssays 26:343,347, 2004. © 2004 Wiley Periodicals, Inc. [source] Continuity and Change in Corporate Governance: comparing Germany and JapanCORPORATE GOVERNANCE, Issue 3 2005Gregory Jackson Germany and Japan are often seen deviating from an economic model of shareholder control and thereby as being similar by virtue of their mutual contrast with the US. Given the common challenges for bank-based and stakeholder-oriented models of corporate governance, Germany,Japan comparison seems particularly timely. This article provides an introductory overview and analysis for the Special Issue by comparing recent developments in corporate law reform, banking and finance, and employment in Germany and Japan. While rejecting arguments for international convergence, we discuss this evidence of simultaneous continuity and change in corporate governance as a potential form of hybridisation of national models or renegotiation of stakeholder coalitions in German and Japanese firms. One consequence is the growing diversity of firm-level corporate governance practices within national systems. [source] Differential expression of polycomb repression complex 1 (PRC1) members in the developing mouse brain reveals multiple complexesDEVELOPMENTAL DYNAMICS, Issue 9 2006Tanja Vogel Abstract Polycomb group (PcG) genes are regulators of body segmentation and cell growth, therefore being important players during development. PcG proteins form large complexes (PRC) that fulfil mostly repressive regulative functions on homeotic gene expression. Although expression of PcG genes in the brain has been noticed, the involvement of PcG genes in the processes of brain development is not understood. In this study, we analysed the expression patterns of PRC1 complex members to reveal PcG proteins that might be relevant for mouse brain development. Using in situ hybridisation, we show PRC1 activity in proliferative progenitor cells during neurogenesis, but also in maturated neuronal structures. PRC1 complex compositions vary in a spatial and temporal controlled manner during mouse brain development, providing cellular tools to act in different developmental contexts of cell proliferation, cell fate determination, and differentiation. Developmental Dynamics 235:2574,2585, 2006. © 2006 Wiley-Liss, Inc. [source] Definition and spatial annotation of the dynamic secretome during early kidney developmentDEVELOPMENTAL DYNAMICS, Issue 6 2006Gemma Martinez Abstract The term "secretome" has been defined as a set of secreted proteins (Grimmond et al. [2003] Genome Res 13:1350,1359). The term "secreted protein" encompasses all proteins exported from the cell including growth factors, extracellular proteinases, morphogens, and extracellular matrix molecules. Defining the genes encoding secreted proteins that change in expression during organogenesis, the dynamic secretome, is likely to point to key drivers of morphogenesis. Such secreted proteins are involved in the reciprocal interactions between the ureteric bud (UB) and the metanephric mesenchyme (MM) that occur during organogenesis of the metanephros. Some key metanephric secreted proteins have been identified, but many remain to be determined. In this study, microarray expression profiling of E10.5, E11.5, and E13.5 kidney and consensus bioinformatic analysis were used to define a dynamic secretome of early metanephric development. In situ hybridisation was used to confirm microarray results and clarify spatial expression patterns for these genes. Forty-one secreted factors were dynamically expressed between the E10.5 and E13.5 timeframe profiled, and 25 of these factors had not previously been implicated in kidney development. A text-based anatomical ontology was used to spatially annotate the expression pattern of these genes in cultured metanephric explants. Developmental Dynamics 235:1709,1719, 2006. © 2006 Wiley-Liss, Inc. [source] Cranial expression of class 3 secreted semaphorins and their neuropilin receptorsDEVELOPMENTAL DYNAMICS, Issue 4 2003John K. Chilton Abstract The semaphorin family of chemorepellents and their receptors the neuropilins are implicated in a variety of cellular processes, including axon guidance and cell migration. Semaphorins may bind more than one neuropilin or a heterodimer of both, thus a detailed knowledge of their expression patterns may reveal possible cases of redundancy or mutual antagonism. To assess their involvement in cranial development, we cloned fragments of the chick orthologues of Sema3B and Sema3F. We then carried out mRNA in situ hybridisation of all six class 3 semaphorins and both neuropilins in the embryonic chick head. We present evidence for spatiotemporal regulation of these molecules in the brainstem and developing head, including the eye, ear, and branchial arches. These expression patterns provide a basis for functional analysis of semaphorins and neuropilins in the development of axon projections and the morphogenesis of cranial structures. Developmental Dynamics 228:726,733, 2003. © 2003 Wiley-Liss, Inc. [source] Sorting nexin-14, a gene expressed in motoneurons trapped by an in vitro preselection methodDEVELOPMENTAL DYNAMICS, Issue 4 2001Patrick Carroll Abstract A gene-trap strategy was set up in embryonic stem (ES) cells with the aim of trapping genes expressed in restricted neuronal lineages. The vector used trap genes irrespective of their activity in undifferentiated totipotent ES cells. Clones were subjected individually to differentiation in a system in which ES cells differentiated into neurons. Two ES clones in which the trapped gene was expressed in ES-derived neurons were studied in detail. The corresponding cDNAs were cloned, sequenced, and analysed by in situ hybridisation on wild-type embryo sections. Both genes are expressed in the nervous system. One gene, YR-23, encodes a large intracellular protein of unknown function. The second clone, YR-14, represents a sorting nexin (SNX14) gene whose expression in vivo coincides with that of LIM-homeodomain Islet-1 in several tissues. Sorting nexins are proteins associated with the endoplasmic reticulum (ER) and may play a role in receptor trafficking. Gene trapping followed by screening based on in vitro preselection of differentiated ES recombinant clones, therefore, has the potential to identify integration events in subsets of genes before generation of mouse mutants. © 2001 Wiley-Liss, Inc. [source] Tritrophic interactions and trade-offs in herbivore fecundity on hybridising host plantsECOLOGICAL ENTOMOLOGY, Issue 3 2004Maria V. Cattell Abstract., 1. Interspecific plant hybridisation can have important evolutionary consequences for hybridising plants and for the organisms that they interact with on multiple trophic levels. In this study the effects of plant hybridisation on the abundance of herbivores and on the levels of herbivore parasitism were investigated. 2. Borrichia frutescens, B. arborescens, and their hybrid (B. × cubana) were censused for Asphondylia borrichiae galls and Pissonotus quadripustulatus plant hoppers in the Florida Keys. Levels of egg parasitism were determined by dissecting parental and hybrid stems and galls for herbivore and parasite eggs and larvae. Stem toughness and gall size are plant-mediated modes of protection from parasitism and these were also measured. For gall midges, fly size was measured as an estimate of fecundity. 3. Field censuses indicated that herbivore abundances varied on hybrid hosts relative to parent plant species and that the different herbivore species exhibited different patterns of abundance. Asphondylia borrichiae gall numbers followed the additive pattern of abundance while P. quadripustulatus numbers most closely resembled the dominance pattern. 4. Parasitism of P. quadripustulatus eggs was high on B. frutescens and the hybrids, and low on B. arborescens, which also had significantly tougher stems. Asphondylia borrichiae suffered the highest levels of parasitism on B. frutescens, the host plant which produced the smallest galls. On B. arborescens, which produced the largest galls, levels of A. borrichiae parasitism were lowest. Both parasitism and gall size were intermediate on the hybrid plants. Galls on B. arborescens and hybrid plants produced significantly smaller flies then those from B. frutescens suggesting that, when selecting hosts from among parent species and hybrids, gall flies may face a trade-off between escape from natural enemies and maximising fecundity. [source] Speciation via species interactions: the divergence of mating traits within speciesECOLOGY LETTERS, Issue 4 2010Conrad J. Hoskin Ecology Letters (2010) 13: 409,420 Abstract A species may overlap with a mosaic of species across its geographic range. Many types of species interaction cause selection on mating traits, but their role in generating within-species divergence has been neglected. The pattern of reproductive character displacement (RCD) has been classically attributed to reinforcement, a process driven by selection against hybridisation. Recent reinforcement research shows that sexual isolation can result between displaced and non-displaced populations. We argue that RCD (and hence potentially speciation) among populations can be generated by a variety of fundamental species interactions beyond reinforcement. We unify these interactions under one process of mating trait divergence and speciation (,RCD speciation'). This process can occur in many geographic settings. Because selection is acting directly on mating traits, rapid speciation can result involving little differentiation in other traits. This pattern of diversification is seen in many groups and regions, and has previously been attributed to sexual selection alone. [source] Detection of EHV-1 and EHV-4 in placental sections of naturally occurring EHV-1- and EHV-4-related abortions in the UK: use of the placenta in diagnosisEQUINE VETERINARY JOURNAL, Issue 5 2003S. GERST Summary Reasons for performing study: EHV-1 and EHV-4 abortion diagnosis is based upon detailed examination of the aborted fetus. However, in some cases, only the placenta is available for examination. Furthermore, the contribution of lesions in the placenta to pathogenesis and diagnosis of EHV-1 and EHV-4 abortion has been neglected. Objectives: To assess the utility of placental examination in equine herpesvirus-1 (EHV-1) and EHV-4 abortion diagnosis. Methods: Sections of allantochorion from 49 herpesvirus abortions were analysed by PCR, in situ hybridisation and immunostaining. Results: Virus-specific nested PCR confirmed the presence of viral DNA in 46 cases; 41 cases were EHV-1-positive and 5 EHV-4-positive. Microscopic changes were nonspecific. Examination of the PCR-positive sections of allantochorion revealed EHV-1 DNA by in situ hybridisation (ISH) in 21 cases and EHV-4 in 4 cases. In 2 samples, DNA of both viruses was present on PCR and ISH. Viral antigen was found by immunohistology in 15 cases. Regarding the localisation of virus in the placentae, both viral DNA and antigen of EHV-1 and EHV-4 were found in endothelial cells of chorionic villi and, occasionally, in trophoblast epithelium. In the stromal endothelium, only EHV-1 was found. Conclusions: The data indicate that examination of placentae is a useful diagnostic aid in EHV-1 and EHV-4 abortion diagnosis. Potential relevance: Virological examination of the placenta should be come standard practice in equine abortion investigations, particularly in those cases where the fetus is not available for examination. [source] A narrow deletion of 7q is common to HCL, and SMZL, but not CLLEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2004Claus Lindbjerg Andersen Abstract: To further characterise the genetic background of the two closely related B-lymphocytic malignancies hairy cell leukaemia (HCL), and splenic marginal zone lymphoma (SMZL) we have identified characteristic copy number imbalances by comparative genomic hybridisation (CGH). Based on these findings, areas of special interest were fine mapped, and relevant probes constructed for use in interphase-fluorescence in situ hybridisation (FISH) investigations. Thus, using the CGH data from 52 HCL and 61 SMZL patients, we identified the characteristic profiles of copy number imbalances for both diseases. These were a gain of 5q13-31 (19%) and loss of 7q22-q35 (6%) for HCL, and gain of 3q25 (28%), loss of 7q31 (16%), and gain of 12q15 (16%) for SMZL. A partial loss of 7q unsual for low-malignant B-cell diseases was found to be common to the two diseases. This loss was therefore fine mapped with BAC/PAC clones. Fine mapping revealed that in SMZL the minimal lost region covers 11.4 Mb spanning from 7q31.33 to 7q33 located between sequence tagged site (STS)-markers SHGC-3275 and D7S725. This area was distinct from the commonly deleted 7q region of myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML). A FISH probe specific for the 7q region was constructed. Using this probe in an interphase-FISH investigation we showed the minimal lost 7q-region of HCL and SMZL to be one and the same. In one HCL case, this investigation furthermore showed the extent of the deleted region to be below the detection limit of CGH, whereas interphase-FISH screening of 36 chronic lymphocytic leukaemia (CLL) cases showed no deletion of the 7q area. In conclusion, we have identified characteristic profiles of copy number imbalances in HCL and SMZL and fine mapped the minimal extent of a commonly lost 7q area of special interest. We hypothesise that this region may contain (a) gene(s) important for the pathology of HCL and SMZL. [source] Characterisation of microbial community composition of a Siberian tundra soil by fluorescence in situ hybridisationFEMS MICROBIOLOGY ECOLOGY, Issue 1 2004Svenja Kobabe Abstract The bacterial community composition of the active layer (0,45 cm) of a permafrost-affected tundra soil was analysed by fluorescence in situ hybridisation (FISH). Arctic tundra soils contain large amounts of organic carbon, accumulated in thick soil layers and are known as a major sink of atmospheric CO2. These soils are totally frozen throughout the year and only a thin active layer is unfrozen and shows biological activity during the short summer. To improve the understanding of how the carbon fluxes in the active layer are controlled, detailed analysis of composition, functionality and interaction of soil microorganisms was done. The FISH analyses of the active layer showed large variations in absolute cell numbers and in the composition of the active microbial community between the different horizons, which is caused by the different environmental conditions (e.g., soil temperature, amount of organic matter, aeration) in this vertically structured ecosystem. Universal protein stain 5-(4,6-dichlorotriazin-2-yl)aminofluorescein (DTAF) showed an exponential decrease of total cell counts from the top to the bottom of the active layer (2.3 × 109,1.2 × 108 cells per gram dry soil). Using FISH, up to 59% of the DTAF-detected cells could be detected in the surface horizon, and up to 84% of these FISH-detected cells could be affiliated to a known phylogenetic group. The amount of FISH-detectable cells decreased with increasing depth and so did the diversity of ascertained phylogenetic groups. [source] Taxon-specific reaction norms to predator cues in a hybrid Daphnia complexFRESHWATER BIOLOGY, Issue 7 2007JUSTYNA WOLINSKA Summary 1. Previous studies have shown that interspecific hybridisation is common among taxa from the Daphnia galeata/hyalina/cucullata species complex. We investigated the influence of predator kairomones on the morphology and life histories of nine clones belonging to three taxa (pure D. galeata, F1 hybrids between D. galeata and D. hyalina, and backcrossed D. hyalina) of this species complex. Predators exerting positive (fish) and negative (Chaoborus larvae) size-selective predation were tested. 2. The most responsive traits were size at maturity and size of neonates. Despite large between-clone variation, discriminant analysis revealed that the three taxa were distinct from each other in key life-history traits. F1 hybrids did not react in an intermediate way compared to the other taxa: the multivariate distances between F1 hybrids and either taxon were larger than between pure D. galeata and backcrossed D. hyalina. 3. The average plasticity (calculated across all traits) was similar for all three taxa. With regard to the size at maturity and neonate body size, the strength of the response was a function of the intrinsic values of these traits expressed in the control. For example, for size at maturity, smaller individuals showed a significantly stronger reaction to Chaoborus kairomones than larger ones. 4. Finally, we monitored seasonal changes in body size, egg number and population density of pure D. galeata and F1 hybrids in Greifensee (Switzerland). The two taxa experienced similar seasonal changes in body size but, on some sampling dates, they differed in mean egg number. The observed seasonal changes in Daphnia body size were consistent with what would be expected if the predator assemblage shifted from fish to Chaoborus over the course of the summer. The fluctuations in the frequencies of Daphnia taxa, however, were not related to seasonal variation in Daphnia body size. 5. Experimental data suggest that temporally heterogeneous predation regimes might be an important condition stabilising the co-occurrence of Daphnia hybrids with parental taxa. Predation regimes, however, cannot solely explain dynamic changes in taxon frequency in Greifensee. [source] A molecular approach to detect hybridisation between crucian carp (Carassius carassius) and non-indigenous carp species (Carassius spp. and Cyprinus carpio)FRESHWATER BIOLOGY, Issue 3 2005B. HÄNFLING Summary 1. Releases of non-native fish into the wild is an increasing problem posing considerable ecological and genetic threats through direct competition and hybridisation. 2. We employed six microsatellite markers to identify first generation hybrids and backcrosses between native crucian carp (Carassius carassius) and introduced goldfish (C. auratus) and common carp (Cyprinus carpio) in the U.K. We also investigated the genetic characteristics of the taxonomically controversial gibel carp (Carassius spp.) from sites across Europe. 3. Natural hybridisation between goldfish and crucian carp occurs frequently, although hybrids between all other species pairs were observed. Only 62% of British crucian carp populations (n = 21) consisted exclusively of pure crucian carp. In some populations hybrids were so frequent, that no pure crucian carp were caught, indicating a high competitive ability of hybrids. 4. Most hybrids belonged to the F1 generation but backcrossing was evident at a low frequency in goldfish × crucian carp hybrids and goldfish × common carp hybrids. Furthermore, some local populations had high frequencies of backcrosses, raising the opportunity for introgression. 5. Gibel carp from Germany and Italy belonged to two triploid clonal lineages that were genetically closely related to goldfish, whereas all individuals identified from British populations proved to be crucian carp × goldfish hybrids. 6. Our study suggests that the release of closely related exotic cyprinids not only poses a threat to the genetic integrity and associated local adaptations of native species, but may also contribute to shifts in community structure through competitive interactions. [source] Can Turner syndrome teach us about the pathogenesis of chronic cholestasis?HEPATOLOGY, Issue 5 2004Piotr Milkiewicz The mechanisms that cause the female predominance of primary biliary cirrhosis (PBC) are uncertain, but the X chromosome includes genes involved in immunological tolerance. We assessed the rate of X monosomy in peripheral white blood cells from 100 women with PBC, 50 with chronic hepatitis C, and 50 healthy controls, by fluorescence in-situ hybridisation. Frequency of X monosomy increased with age in all groups, but was significantly higher in women with PBC than in controls (p<0.0001); age-adjusted back-transformed mean frequencies were 0.050 (95% CI 0.046-0.055) in women with PBC, 0.032 (0.028-0.036) in those with chronic hepatitis C, and 0.028 (0.025-0.032) in controls. We suggest that haploinsufficiency for specific X-linked genes leads to female susceptibility to PBC. [source] The Medical History of South Africa: An OverviewHISTORY COMPASS (ELECTRONIC), Issue 5 2008Anne Digby The article surveys half a century of historical writing on South African medicine, which is defined widely to include discussion of health care professions, public health, hospitals and asylums, and indigenous medicine as well as the cross-overs and hybridisation between biomedicine and indigenous medicine. A rapidly growing historiography has been influenced both by general literature in the history of medicine as well as by the more specific context of South Africa. Here the colonial and post-colonial pasts shape the present to an unusual extent and the legacy both of apartheid and of an ongoing democratic transformation impact on the historian's choice of subject. [source] Insights into the termite assemblage of a neotropical rainforest from the spatio-temporal distribution of flying alatesINSECT CONSERVATION AND DIVERSITY, Issue 3 2009THOMAS BOURGUIGNON Abstract., 1. During the last decade, many studies have focused on the diversity of termite species and their ecological function, but these have been mostly based on transect protocols not designed to sample canopy-dwelling and subterranean species. Additionally, all these studies relied upon collections of foraging parties composed of workers and soldiers in the soil or in pieces of wood. 2. We hypothesised that alate-based protocols could disclose spatial and temporal patterns of termite flights and provide a more balanced picture of assemblages for ecological and biodiversity surveys. 3. Our study took place in the framework of the IBISCA-Panama project, which used numerous trapping methods to give a multifaceted overview of a complex tropical rainforest arthropod community. Two methods, flight interception traps and light traps, were efficient at collecting termite alates. All collected specimens were assigned to morphospecies which were later identified to the genus or species level, when possible. 4. Our results highlighted that: (i) alate trapping represents a powerful complement to ground-based standardised sampling protocols by allowing the documentation of the whole termite assemblage. (ii) Canopy dwellers fly preferentially in the upper strata, whereas no vertical stratification was found for ground dwellers, suggesting that height of flight is dictated by a pressure for long distance dispersal as well as the need to find a suitable site for colony-founding. (iii) Alates from closely related species do not stagger their flight period to avoid hybridisation but rather synchronise their flights according to environmental factors. [source] Chromosomes 6 and 18 induce neoplastic suppression in epithelial ovarian cancer cells,INTERNATIONAL JOURNAL OF CANCER, Issue 5 2009Dimitra Dafou Abstract Metaphase comparative genomic hybridisation (CGH) studies indicate that chromosomes 4, 5, 6, 13, 14, 15 and 18 are frequently deleted in primary ovarian cancers (OCs). Therefore we used microcell-mediated chromosome transfer (MMCT) to establish the functional effects of transferring normal copies of these chromosomes into 2 epithelial OC cell lines (TOV112D and TOV21G). The in vitro neoplastic phenotype (measured as anchorage dependent and independent growth and invasion) was compared between recipient OC cell lines and multiple MMCT hybrids. Chromosomes 6 and 18 showed strong evidence of functional, neoplastic suppression for multiple hybrids in both cell lines. We also found evidence in 1 cancer cell line suggesting that chromosomes 4, 13 and 14 may also cause functional suppression. Array CGH and microsatellite analyses were used to characterise the extent of genomic transfer in chromosome 6 and 18 hybrids. A 36 MB deletion on chromosome 6 in 2 hybrids from 1 cell line mapped the candidate region proximal to 6q15 and distal to 6q22.2; and an ,10 MB candidate region spanning the centromere on chromosome 18 was identified in 2 hybrids from the other cell line. These data support reported functional effects of chromosome 6 in OC cell lines; but to our knowledge, this is the first time that functional suppression for chromosome 18 has been reported. This suggests that these chromosomes may harbour tumour suppressor-"like" genes. The future identification of these genes may have a significant impact on the understanding and treatment of the disease and the identification of novel therapeutic targets. © 2008 Wiley-Liss, Inc. [source] Phylogeny of major lineages of suboscines (Passeriformes) analysed by nuclear DNA sequence dataJOURNAL OF AVIAN BIOLOGY, Issue 1 2001Martin Irestedt Phylogenetic relationships among major groups of passeriform birds were studied by analyses of nucleotide sequence data from two nuclear genes, c- myc and RAG-1. The results corroborated both the monophyly of the order Passeriformes, and the major dichotomy into oscine and suboscine passerines previously suggested based on syringeal morphology and DNA-DNA hybridizations. The representatives of the Old World suboscines (families Eurylaimidae, Philepittidae and Pittidae) formed a monophyletic clade. The New World suboscines clustered into two clades. The first contained Conopophaga (Conopophagidae), Furnarius (Furnariidae), Lepidocolaptes (Dendrocolaptidae), Thamnophilus (Formicariidae), and Rhinocrypta (Rhinocryptidae). Previously, the monophyly of this group has been inferred from their possession of a unique, "tracheophone" syrinx, and from DNA-DNA hybridisation data. The second clade of New World suboscines includes Gubernetes and Muscivora (Tyrannidae), Phytotoma (Phytotomidae), Tityra (Cotingidae) and Pipra (Pipridae). This group of families have been considered monophyletic based on morphology (although ambiguously) and DNA-DNA hybridisation. The sister group relationship of Tityra and Phytotoma supports the previously supposed cotingid affinity of Phytotoma. Nuclear DNA data also unambiguously group the lyrebirds Menura with the oscines. The presented results from the analysis of nuclear DNA agree well with morphology and DNA-DNA hybridisation data. The precise age of the divergences studied herein are unknown but based on interpretations of the fossil record of passerine birds many of them might date back to the early Tertiary. The agreement between data from the nuclear DNA and other sources, along with the fact that neither of the studied genes showed sign of saturation, indicate the great potential of these two nuclear genes to resolve very old divergences in birds. [source] Environmental- and parental condition-related variation in sex ratio of kestrel broodsJOURNAL OF AVIAN BIOLOGY, Issue 2 2000Erkki Korpimäki Variation of brood sex ratio was studied in a Finnish population of Eurasian Kestrels Falco tinnunculus breeding in an unpredictably variable environment. From those young that survived until 2,4 weeks of age, blood was collected and their sex determined from polymorphic DNA profiles produced by hybridisation with a human minisatellite probe. The sex ratio was male-biased during a year of food (vole) scarcity. Furthermore, in broods without mortality, contrasting seasonal trends in sex ratios emerged. In this subsample, the proportion of males increased with later laying date during years of low and moderate food supply, whereas the opposite was true in a year of relatively high food supply. These trends may indicate circumstances that favour the raising of different sex. The proportion of males in the brood was negatively correlated with body condition of both male and female parents, also reflecting an adaptive condition-dependent sex-ratio adjustment, or alternatively the inability of the parents to meet the requirements of the more energetically expensive female offspring. We discuss the limitations that unpredictable conditions during brood raising can impose on adaptive sex-ratio manipulation, particularly in species with sexual size dimorphism and consequent differences in the cost of raising the two sexes. [source] Simultaneous detection and differentiation of human polyomaviruses JC and BK by a rapid and sensitive PCR-ELAHA assay and a survey of the JCV subtypes within an Australian populationJOURNAL OF MEDICAL VIROLOGY, Issue 3 2004David M. Whiley Abstract Human polyomaviruses JCV and BKV can cause several clinical manifestations in immunocompromised hosts, including progressive multifocal leukoencephalopathy (PML) and haemorrhagic cystitis. Molecular detection by polymerase chain reaction (PCR) is recognised as a sensitive and specific method for detecting human polyomaviruses in clinical samples. In this study, we developed a PCR assay using a single primer pair to amplify a segment of the VP1 gene of JCV and BKV. An enzyme linked amplicon hybridisation assay (ELAHA) using species-specific biotinylated oligonucleotide probes was used to differentiate between JCV and BKV. This assay (VP1-PCR-ELAHA) was evaluated and compared to a PCR assay targeting the human polyomavirus T antigen gene (pol - PCR). DNA sequencing was used to confirm the polyomavirus species identified by the VP1-PCR-ELAHA and to determine the subtype of each JCV isolate. A total of 297 urine specimens were tested and human polyomavirus was detected in 105 specimens (35.4%) by both PCR assays. The differentiation of JCV and BKV by the VP1-PCR-ELAHA showed good agreement with the results of DNA sequencing. Further, DNA sequencing of the JCV positive specimens showed the most prevalent JCV subtype in our cohort was 2a (27%) followed by 1b (20%), 1a (15%), 2c (14%), 4 (14%) and 2b (10%). The results of this study show that the VP1-PCR-ELAHA is a sensitive, specific and rapid method for detecting and differentiating human polyomaviruses JC and BK and is highly suitable for routine use in the clinical laboratory. J. Med. Virol. 72:467,472, 2004. © 2004 Wiley-Liss, Inc. [source] Defective human T-cell leukaemia virus type 1 (HTLV-1) genomes: No evidence in serologically indeterminate german blood donors but new type detected in established cell linesJOURNAL OF MEDICAL VIROLOGY, Issue 1 2002V.A. Morozov Abstract Individuals reactive in antibody screening tests (ELISA) and with one or more reactions to HTLV-1 proteins on Western blotting, but lacking the criteria of a confirmed HTLV infection, are not exceptional in regions with a low prevalence of HTLV-1/-2 infections. PCR analysis of these indeterminate samples, using "diagnostic" pol and tax sets of primers, give negative results. However, expression of HTLV-1 defective proviruses with internal deletions undetectable by PCR with diagnostic primers could have taken place. Seven German HTLV-1 ELISA-reactive blood donors, who showed reactivity also in Western blots against several viral proteins, and twenty haemophiliacs, were examined by nested PCR and/or PCR/Southern hybridisation with primers designed for detection of HTLV-1 defective proviruses. No HTLV-1-specific amplification products were obtained. However, HTLV-1 defective proviruses with large internal deletions were detected in four out of five cell lines established from symptomatic HTLV-1 cases and two in HUT-102 cells. In two amplicons, short inverted rRNA sequences between gag and env fragments of HTLV-1 defective proviruses were revealed. These results do not exclude the presence of defective HTLV-1 proviruses in individuals with indeterminate serology although this is unlikely. J. Med. Virol. 66:102,106, 2002. © 2002 Wiley-Liss, Inc. [source] Loss of Hypothalamic Response to Leptin During Pregnancy Associated with Development of Melanocortin ResistanceJOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2009S. R. Ladyman Hypothalamic leptin resistance during pregnancy is an important adaptation that facilitates the state of positive energy balance required for fat deposition in preparation for lactation. Within the arcuate nucleus, pro-opiomelanocortin (POMC) neurones and neuropeptide Y (NPY)/agouti-related gene protein (AgRP) neurones are first-order leptin responsive neurones involved in the regulation of energy balance. The present study aimed to investigate whether the regulation of these neuropeptides is disrupted during pregnancy in association with the development of leptin resistance. As measured by quantitative in situ hybridisation, POMC and AgRP mRNA levels were not significantly different during pregnancy, whereas NPY mRNA levels increased such that, by day 21 of pregnancy, levels were significantly higher than in nonpregnant, animals. These data suggest that these neurones were not responding normally to the elevated leptin found during pregnancy. To further characterise the melanocortin system during pregnancy, double-label immunohistochemistry was used to quantify leptin-induced phosphorylation of signal transducer and activator of transcription 3 (pSTAT3) in POMC neurones, using ,-melanocyte-stimulating hormone (MSH) as a marker. The percentage of ,-MSH neurones containing leptin-induced pSTAT3 did not significantly differ from nonpregnant animals, indicating that there was no change in the number of POMC neurones that respond to leptin during pregnancy. Treatment with ,-MSH significantly reduced food intake in nonpregnant rats, but not in pregnant rats, indicating resistance to the satiety actions of ,-MSH during pregnancy. The data suggest that multiple mechanisms contribute to leptin resistance during pregnancy. As well as a loss of responses in first-order leptin-responsive neurones in the arcuate nucleus, there is also a downstream disruption in the melanocortin system. [source] Serotonergic and Catecholaminergic Interactions with Co-Localised Dopamine-Melatonin Neurones in the Hypothalamus of the Female TurkeyJOURNAL OF NEUROENDOCRINOLOGY, Issue 1 2009S. W. Kang Serotonin and catecholamines (dopamine, norepinephrine, epinephrine) have important roles as neurotransmitters in avian reproduction, but their anatomical relationship to the neuroendocrine circuitry that regulates reproduction is poorly understood. Our previous studies have shown that co-localised dopamine-melatonin (DA-MEL) neurones in the avian premammillary nucleus (PMM) are active during periods of photoresponsiveness and, therefore, are potentially photosensitive neurones. Because serotonergic and catecholaminergic neurotransmitters are important regulators of reproductive function in the female turkey, we hypothesised that the serotonergic/catecholaminergic neurones within the brainstem might interact with PMM DA-MEL neurones and constitute an important circuit for reproductive function. To examine this possible interaction, the retrograde fluorescent tract tracer, 1,1,dioctadecyl-3,3,3,3,-tetramethyleindocarbocyanine perchlorate (DiI) was injected into the PMM, and combined with serotonin, tyrosine hydroxylase (TH), dopamine ,-hydroxylase (DBH) and phenyl N -methyltransferse (PNMT) immunocytochemistry to reveal neuroanatomical connections. Changes in the activities of serotonergic, dopaminergic, adrenergic and noradrenergic neuronal systems projecting to the PMM were measured at different reproductive states with in situ hybridisation (ISH) techniques, using tryptophan hydroxylase 2 (TPH2) and TH mRNA expression, respectively. Cells labelled with DiI were found in anatomically discrete areas in or near the hypothalamus and the brainstem. Double immunocytochemistry confirmed that there were serotonin, DBH and PNMT fibres in close apposition to DA-MEL neurones. TPH2 mRNA expression in serotonin neurones was found in several nuclei, and its most abundant mRNA expression was seen in the nucleus Locus ceruleus of laying and incubating hens. TH mRNA expression levels in the six catecholaminegic areas labelled with DiI was measured across the different reproductive states. In the nucleus tractus solitarius (adrenergic), the highest level of TH mRNA expression was found in photorefractory hens and the lowest level in incubating hens. These observed patterns of serotonin/catecholamine neuronal distribution and their variable interactions with PMM DA-MEL neurones during different reproductive states may offer a significant neuroanatomical basis for understanding the control of avian reproductive seasonality. [source] Rhythm-Dependent Light Induction of the c-fos Gene in the Turkey HypothalamusJOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2007A. Thayananuphat Day length (photoperiod) is a powerful synchroniser of seasonal changes in the reproductive neuroendocrine activity in temperate-zone birds. When exposed to light during the photoinducible phase, reproductive neuroendocrine responses occur. However, the neuroendocrine systems involved in avian reproduction are poorly understood. We investigated the effect of light exposure at different circadian times upon the hypothalamus and components of the circadian system, using c-fos mRNA expression, measured by in situ hybridisation, as an indicator of light-induced neuronal activity. Levels of c-fos mRNA in these areas were compared after turkey hens (on a daily 6-h light period) had been exposed to a 30-min period of light occurring at 8, 14, or 20 h after the onset of first light of the day (subjective dawn). Non-photostimulated control birds were harvested at the same times. In birds, photostimulated within the photoinducibile phase (14 h), in contrast to before or after, c-fos mRNA was significantly increased in the nucleus commissurae pallii (nCPa), nucleus premamillaris (PMM), eminentia mediana (ME), and organum vasculosum lamina terminalis (OVLT). Photostimulation increased c-fos mRNA expression in the pineal gland, nucleus suprachiasmaticus, pars visualis (vSCN) and nucleus inferioris hypothalami compared to that of their corresponding nonphotostimulated controls. However, the magnitudes of the responses in these areas were similar irrespective of where in the dark period the pulses occurred. No c-fos mRNA was induced in the nucleus infundibulari, in response to the 30-min light period at any of the circadian times tested. The lack of c-fos up-regulation in the pineal gland and vSCN following photostimulation during the photoinducible phase lends credence to the hypothesis that these areas are not involved in the photic initiation of avian reproduction. On the other hand, c-fos mRNA increases in the nCPa, ME, and OVLT support other studies showing that these areas are involved in the onset of reproductive behaviour initiated by long day lengths. The present study provides novel data showing that the PMM in the caudal hypothalamus is involved in the neuronally mediated, light-induced initiation of reproductive activity in the turkey hen. [source] Altered Expression of SOCS3 in the Hypothalamic Arcuate Nucleus during Seasonal Body Mass Changes in the Field Vole, Microtus agrestisJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2007E. Król We have previously shown that cold-acclimated (8 °C) male field voles (Microtus agrestis) transferred from short day (SD, 8 h light) to long day (LD, 16 h light) photoperiod exhibit an increase in body mass lasting 4 weeks, after which they stabilise at a new plateau approximately 7.5 g (24.8%) higher than animals maintained in SD. By infusing voles with exogenous leptin, we have also demonstrated that SD voles respond to the hormone by reducing body mass and food intake, whereas LD animals increasing body mass are resistant to leptin treatment. In the present study, we investigated whether seasonal changes in body mass could be linked to modulation of the leptin signal by suppressor of cytokine signalling-3 (SOCS3). We used in situ hybridisation to examine hypothalamic arcuate nucleus (ARC) expression of SOCS3, neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) genes in 90 voles exposed to either SD or LD for up to 11 weeks. LD voles increasing body mass had significantly higher levels of SOCS3 mRNA than SD or LD voles with a stable body mass. There were no associated changes in expression of NPY, AgRP, POMC and CART genes. These results suggest that voles that regulate body mass at either the lower (SD) or upper (LD) plateau remain sensitive to leptin action, whereas SOCS3-mediated leptin resistance is a short-term mechanism that enables animals to move between the stable body mass plateaus. Our data provide evidence that expression of SOCS3 in the ARC is involved in the modulation of the strength of the leptin signal to facilitate seasonal cycles in body mass and adiposity. [source] Stroke Injury in Rats Causes an Increase in Activin A Gene Expression Which is Unaffected by Oestradiol TreatmentJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2006M. Böttner Abstract Activins are members of the transforming growth factor-, superfamily that exert neurotrophic and neuroprotective effects on various neuronal populations. To determine the possible function of activin in stroke injury, we assessed which components of the activin signalling pathway were modulated in response to middle cerebral artery occlusion (MCAO). Furthermore, because oestradiol replacement protects against MCAO-induced cell death, we explored whether oestradiol replacement influences activin gene expression. Female Sprague-Dawley rats underwent permanent MCAO and the expression of activins and their corresponding receptors was determined by semiquantitative reverse transcriptase-polymerase chain reaction at 24 h after onset of ischaemia. We observed up-regulation of activin ,A and activin type I receptor A mRNA in response to injury. Dual-label immunocytochemistry followed by confocal z-stack analysis showed that the activin A expressing cells comprised neurones. Next, we monitored the time course of activin ,A mRNA expression in oestradiol- or vehicle-treated rats at 4, 8, 16 and 24 h after MCAO via in situ hybridisation. Starting at 4 h after injury, activin ,A mRNA was up-regulated in cortical and striatal areas in the ipsilateral hemisphere. Activin ,A mRNA levels in the cortex increased dramatically with time and were highest at 24 h after the insult, and oestradiol replacement did not influence this increase. [source] Noradrenergic Regulation of Hypothalamic Cells that Produce Growth Hormone-Releasing Hormone and Somatostatin and the Effect of Altered Adiposity in SheepJOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2005J. Iqbal Abstract The growth hormone (GH) axis is sensitive to alteration in body weight and there is evidence that central noradrenergic systems regulate neurones that produce growth hormone-releasing hormone (GHRH) and somatostatin (SRIF). This study reports semiquantitative estimates of the noradrenergic input to neuroendocrine GHRH and SRIF neurones in the sheep of different body weights. We also studied the effects of altered body weight on expression of dopamine ,-hydroxylase (DBH), the enzyme that produces noradrenalin from dopamine. Ovariectomised ewes were made Lean (39.6 ± 2.6 kg; Mean ± SEM) by dietary restriction, whereas Normally Fed animals (61.2 ± 0.8 kg) were maintained on a regular diet. Brains were perfused for immunohistochemistry and in situ hybridisation. The Mean ± SEM number of GHRH-immunoreactive (-IR) cells was lower in Normally Fed (65 ± 7) than in Lean (115 ± 14) animals, whereas the number of SRIF-IR cells was similar in the two groups (Normally Fed, 196 ± 17; Lean 230 ± 21). Confocal microscopic analysis revealed that the percentage of GHRH-IR cells (Normally Fed 36 ± 1.5% versus Lean 32 ± 4.6%) and percentage of SRIF-IR cells (Normally Fed 30 ± 40.4% versus Lean 32 ± 2.3%) contacted by noradrenergic fibres did not change with body weight. FluoroGold retrograde tracer injections confirmed that noradrenergic projections to the arcuate nucleus are from ventrolateral medulla and noradrenergic projections to periventricular nucleus arise from the ventrolateral medulla, nucleus of solitary tract, locus coeruleus (LC) and the parabrachial nucleus (PBN). DBH expressing cells were identified using immunohistochemistry and in situ hybridisation and the level of expression (silver grains/cell) quantified by image analysis. The number of DBH cells was similar in Normally Fed and Lean animals, but the level of expression/cell was lower (P < 0.02) in the PBN and LC of Lean animals. These results provide an anatomical basis for the noradrenergic regulation of GHRH and SRIF cells and GH secretion. Altered activity or noradrenergic neurones in the PBN and LC that occur with reduced body weight may be relevant to the control of GH axis. [source] Introduction of a High-Energy Diet Acutely Up-Regulates Hypothalamic Cocaine and Amphetamine-Regulated Transcript, Mc4R and Brown Adipose Tissue Uncoupling Protein-1 Gene Expression in Male Sprague-Dawley RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 1 2005Z. A. Archer Abstract Obesity is an escalating problem in Western societies. Susceptibility to weight gain within an obesogenic environment is variable. It remains unclear how the range of weight gain responses are generated. It is possible that an individual's immediate and/or sustained appetite for apparently palatable foods, or metabolic adaptations to a new diet could be important. The present study therefore examined the short- to medium-term effects of a high-energy (HE) diet on bodyweight, food intake, and energy balance-related signalling systems. Sprague-Dawley rats were fed either chow or an HE diet for 12 h, 24 h, 48 h or 14 days. Blood hormones and metabolites were assayed, and expression of uncoupling protein-1 (UCP-1) and hypothalamic energy-balance related genes were determined by Northern blotting or in situ hybridisation, respectively. Short-term exposure (12 h, 24 h, 48 h) to the HE diet had no effect on grams of food consumed, but caloric intake was increased. Exposure to HE diet for 14 days (medium term) established a bodyweight differential of 7.7 g, and animals exhibited a transient increase in caloric intake of 5 days duration. Terminal levels of leptin, insulin, glucose and non-esterified fatty acids (NEFAs) were all increased in HE-fed animals. UCP-1 mRNA was elevated in interscapular brown adipose tissue from HE-fed rats only at 12 h. Cocaine and amphetamine-regulated transcript (CART) and Mc4R gene expression in the hypothalamus were increased after 12 h and 24 h on an HE diet, respectively. The rats appear to passively over-consume calories as a result of consuming a similar weight of a more energy dense food. This evokes physiological responses, which adjust caloric intake over several days. Circulating NEFA and insulin concentrations, UCP-1, Mc4R and CART gene expression are increased as an immediate consequence of consuming HE diet, and may be involved in countering hypercaloric intake. Circulating leptin is increased in the HE-fed animals after 48 h, reflecting their increasing adiposity. [source] Absence of leukocyte microchimerism in oral lichen planus (OLP): an in situ hybridisation studyJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 7 2001T. Lombardi Abstract: Oral lichen planus (OLP) is a relatively common chronic inflammatory disease. The majority of patients are between 30 and 50 years of age with a higher incidence in females. The aetiology is unknown and various hypotheses on the pathogenic mechanisms, including autoimmunity, have been proposed over the years. In the present study, we investigated whether leukocyte microchimerism, a biological situation implicated in the aetiology of some autoimmune diseases, might play a role in the pathogenesis of OLP. We used in situ hybridisation to identify Y chromosome DNA in a series of formalin-fixed paraffin-embedded oral mucosa biopsies of women with established clinical and histological disease who had given birth to a male child. The positive control, two mucosal specimens from a man with OLP, showed over 90% of keratinocytes and cells within the inflammatory infiltrate, a positive nuclear signal. The negative control, biopsies from three women having carried only female foetuses and one nulliparous woman, all with OLP, did not show any nuclear signal. In the fifteen selected cases of OLP biopsies from women who had only male offspring, nucleated cells containing the Y chromosome were not detected within the chronic inflammatory infiltrate. These results suggest that unlike some other immunologically mediated diseases, leukocyte microchimerism does not seems to be involved in the pathogenesis of OLP. [source] | |||||||||||||||||||||||||||||||||||||