Identification of genes targeted by FSH and oocytes in porcine granulosa cells

In the mammalian ovarian follicle maturing oocytes are nurtured and supported by surrounding somatic cells, the mural granulosa cells and the cumulus cells. These cells are regulated by follicle-stimulating hormone (FSH), originating from the pituitary, and paracrine factors derived from the oocyte. To gain insight into the mechanisms involved in the regulation of granulosa cell function, this study aimed to identify genes in mural granulosa cells that are regulated by FSH and oocyte secreted factors using the pig as a model organism. Mural granulosa cells were collected from 3-6 mm follicles from sow ovaries and cultured in serum free medium in the presence or absence of FSH and/or isolated cumulus oocyte complexes (COCs). FSH significantly increased both the metabolic activity and progesterone production of granulosa cells, while the presence of COCs reversed these FSH effects. Expression levels of mRNA in the absence/presence of FSH and COCs were analyzed on porcine specific microarrays representing 11,300 genes. Both previously identified and novel FSH target genes as well as some oocyte affected genes were found. Expression of inhibitor of DNA binding protein 2 and 3, ID2 and ID3, was decreased by FSH but increased by COCs, as validated by quantitative PCR. These proteins function as dominant negative basic helix loop helix (bHLH) transcription factors and since all regulated genes contain the consensus E-box sequence that can bind bHLH factors, our data suggest that FSH and COCs may regulate granulosa cell function by tuning the activity of bHLH factors, through ID2 and ID3.

Persistent Mullerian duct syndrome in a Miniature Schnauzer dog with signs of feminization and a Sertoli cell tumour

A 5-year-old male Miniature Schnauzer was presented with unilateral cryptorchidism and signs of feminization. Abdominal ultrasonography revealed an enlarged right testis and a large, fluid-filled cavity that appeared to arise from the prostate. Computed tomography revealed the cavity to be consistent with an enlarged uterine body, arising from the prostate, and showed two structures resembling uterine horns that terminated close to the adjacent testes. The dog had a normal male karyotype, 78 XY. Gonadohysterectomy was performed and both the surgical and the histological findings confirmed the presence of a uterus in this male animal, resulting in a diagnosis of persistent Mullerian duct syndrome (PMDS). The enlarged intra-abdominal testis contained a Sertoli cell tumour. Computed tomography proved to be an excellent diagnostic tool for PMDS.

Minimal external masculinization in a SRY-negative XX male Podenco dog

Normal mammalian sex differentiation takes place in three genetically controlled steps: chromosomal sex determination (XX or XY), gonadal differentiation and development of the phenotypic sex. Animals are considered to be sex reversed if chromosomal sex determination and gonadal development are not in agreement. In this report, sex reversal is described in a 1.5-year-old Podenco dog that was referred because of suspected recurrent growth of a previously removed os clitoridis in the vulva. With that exception the dog was phenotypically female, but had never been in oestrus and exhibited male behaviour. Abdominal ultrasonography showed a small tubular structure dorsal to the bladder, consistent with a uterus. An ovoid structure resembling a gonad was visible between the right kidney and inguinal canal. Plasma testosterone concentrations before and after GnRH administration indicated the presence of functional testicular tissue. Two testes, each with its epididymis and ductus deferens, and a complete bicornuate uterus were removed surgically. Cytogenetic analysis of peripheral blood lymphocytes showed a normal female karyotype (78, XX). These findings are consistent with the diagnosis of an XX male. PCR analysis of genomic DNA revealed that the SRY gene was absent. In summary, this report describes the first SRY-negative XX male Podenco dog with an almost complete female phenotype despite high basal and stimulated plasma testosterone concentrations. It is hypothesized that the clinical observations in this dog may have been caused by reduced and delayed Müllerian-inhibiting substance secretion and the absence of conversion of testosterone to dihydrotestosterone due to 5alpha-reductase deficiency.

Blastocyst morphology, actin cytoskeleton quality and chromosome content are correlated with embryo quality in the pig

Embryo survival rates obtained after transfer of in vitro produced porcine blastocysts are very poor. This is probably related to poor quality of the embryos. The aim of the present study was to determine markers for good quality blastocysts. Therefore, we tried to link blastocyst morphology to several morphological and cell biological properties, and evaluated the survival of in vitro produced, morphologically classified, blastocysts following non-surgical transfer. In vitro and in vivo produced blastocysts were allocated to two groups (classes A and B) on the basis of morphological characteristics. The quality of their actin cytoskeleton, their total cell number, their ability to re-expand after cytochalasin-B treatment and the occurrence of numerical chromosome aberrations were studied and compared. In vivo produced blastocysts were used as a control. Our results indicate that the ability of blastocysts to re-expand after cytochalasin-B-induced actin depolymerization was positively correlated with the morphology of the blastocyst, and associated with the quality of the actin cytoskeleton. Chromosome analysis revealed that mosaicism is inherent to the in vitro production of porcine embryos, but also that in vivo produced blastocysts contained some non-diploid cells. In non-surgical embryo transfer experiments more recipients receiving class A blastocysts were pregnant on Day 20 than those receiving class B blastocysts. One recipient gave birth to six piglets from class A in vitro produced blastocysts, providing a verification of the enhanced viability of blastocysts that were scored as 'good' on the basis of their morphology.

Physiological and molecular responses of Lactuca sativa to colonization by Salmonella enterica serovar Dublin

This paper describes the physiological and molecular interactions between the human-pathogenic organism Salmonella enterica serovar Dublin and the commercially available mini Roman lettuce cv. Tamburo. The association of S. enterica serovar Dublin with lettuce plants was first determined, which indicated the presence of significant populations outside and inside the plants. The latter was evidenced from significant residual concentrations after highly efficient surface disinfection (99.81%) and fluorescence microscopy of S. enterica serovar Dublin in cross sections of lettuce at the root-shoot transition region. The plant biomass was reduced significantly compared to that of noncolonized plants upon colonization with S. enterica serovar Dublin. In addition to the physiological response, transcriptome analysis by cDNA amplified fragment length polymorphism analysis also provided clear differential gene expression profiles between noncolonized and colonized lettuce plants. From these, generally and differentially expressed genes were selected and identified by sequence analysis, followed by reverse transcription-PCR displaying the specific gene expression profiles in time. Functional grouping of the expressed genes indicated a correlation between colonization of the plants and an increase in expressed pathogenicity-related genes. This study indicates that lettuce plants respond to the presence of S. enterica serovar Dublin at physiological and molecular levels, as shown by the reduction in growth and the concurrent expression of pathogenicity-related genes. In addition, it was confirmed that Salmonella spp. can colonize the interior of lettuce plants, thus potentially imposing a human health risk when processed and consumed.

A Multiplex Real-Time Polymerase Chain Reaction (TaqMan) Assay for the Simultaneous Detection of Meloidogyne chitwoodi and M. fallax

ABSTRACT This study describes a multiplex real-time polymerase chain reaction (PCR) approach for the simultaneous detection of Meloidogyne chitwoodi and M. fallax in a single assay. The approach uses three fluorogenic minor groove binding (MGB) TaqMan probes: one FAM-labeled to detect M. chitwoodi, one VIC-labeled to detect M. fallax, and one NED-labeled to detect the internal amplification control (IAC) to monitor false negative results. One common primer set is used for the amplification of part of the internal transcribed spacer (ITS) region of M. chitwoodi and M. fallax and one primer set for the amplification of the IAC. The test enabled detection of M. chitwoodi and/or M. fallax in DNA samples extracted from batches of juveniles, from single juveniles, and from infected plant material. Compared with current assays to detect M. chitwoodi and M. fallax, the multiplex real-time PCR offers the following advantages: it is faster because the test can simultaneously detect both quarantine species without the need for post-PCR processing; and it is at least 10 times more sensitive than a comparable regular PCR also targeting the ITS sequence. Inclusion of the IAC facilitates the interpretation of the FAM and VIC cycle threshold (Ct) values and can prevent the scoring of false negative results when FAM, VIC, and NED Ct values are high. The test allows precise quantification when only one of the two species is present in the sample. However, experiments with mixtures of genomic DNA of M. chitwoodi and M. fallax revealed that the ability of the multiplex real-time PCR assay to detect small quantities of DNA of one species is reduced when large quantities of DNA of the other species are present.

Comparison of methods of extracting Salmonella enterica serovar Enteritidis DNA from environmental substrates and quantification of organisms by using a general internal procedural control

This paper compares five commercially available DNA extraction methods with respect to DNA extraction efficiency of Salmonella enterica serovar Enteritidis from soil, manure, and compost and uses an Escherichia coli strain harboring a plasmid expressing green fluorescent protein as a general internal procedural control. Inclusion of this general internal procedural control permitted more accurate quantification of extraction and amplification of S. enterica serovar Enteritidis in these samples and reduced the possibility of false negatives. With this protocol it was found that the optimal extraction method differed for soil (Mobio soil DNA extraction kit), manure (Bio101 soil DNA extraction kit), and compost (Mobio fecal DNA extraction kit). With each method, as little as 1.2 x 10(3) to 1.8 x 10(3) CFU of added serovar Enteritidis per 100 mg of substrate could be detected by direct DNA extraction and subsequent S. enterica-specific TaqMan PCR. After bacterial enrichment, as little as 1 CFU/100 mg of original substrate was detected. Finally, the study presents a more accurate molecular analysis for quantification of serovar Enteritidis initially present in soil or manure using DNA extraction and TaqMan PCR.

The canine sarcoglycan delta gene: BAC clone contig assembly, chromosome assignment and interrogation as a candidate gene for dilated cardiomyopathy in Dobermann dogs

Dilated cardiomyopathy (DCM) is a common disease of the myocardium recognized in human, dog and experimental animals. Genetic factors are responsible for a large proportion of cases in humans, and 17 genes with DCM causing mutations have been identified. The genetic origin of DCM in the Dobermann dogs has been suggested, but no disease genes have been identified to date. In this paper, we describe the characterization and evaluation of the canine sarcoglycan delta (SGCD), a gene implicated in DCM in human and hamster. Bacterial artificial chromosomes (BACs) containing the canine SGCD gene were isolated with probes for exon 3 and exons 4-8 and were characterized by Southern blot analysis. BAC end sequences were obtained for four BACs. Three of the BACs overlapped and could be ordered relative to each other and the end sequences of all four BACs could be anchored on the preliminary assembly of the dog genome sequence (www. ensembl.org). One of the BACs of the partial contig was localized by fluorescent in situ hybridization to canine chromosome 4q22, in agreement with the dog genome sequence. Two highly informative polymorphic microsatellite markers in intron 7 of the SGCD gene were identified. In 25 DCM-affected and 13 non DCM-affected dogs seven different haplotypes could be distinguished. However, no association between any of the SGCD variants and the disease locus was apparent.

Comparison of real-time PCR methods for detection of Salmonella enterica and Escherichia coli O157:H7, and introduction of a general internal amplification control

The objectives of this study were to compare different real-time PCR-based methods for detection of either Salmonella spp. or E. coli O157:H7 with respect to sensitivity, precision and accuracy. In addition, a general internal amplification control (IAC) is presented, allowing prevention of false negative results. The IAC allows insight in amplification efficiency and enables a more accurate quantification with the evaluated real-time PCR methods. Implementation of the IAC with the different PCR methods did not affect the precision of the methods, but the sensitivity was reduced 10-fold. Introduction of an IAC with the Salmonella enterica specific detection method showed a shift in Ct-value (increase of target Ct-value with 0.45+/-0.17 cycles), while with the method to detect E. coli O157:H7 no influence of IAC co-amplification was observed. The quantification threshold of the methods in which the IAC was included was determined at 1 pg of target DNA (equal to 200 CFU) per reaction. Qualitative detection was feasible down to 10 fg of target DNA per reaction using both methods in which the IAC was incorporated. The adjusted methods have the potential to provide fast and sensitive detection of Salmonella spp. or E. coli O157:H7, enabling accurate quantification and preventing false negative results by using the general IAC.

Comparative chromosome painting between the domestic pig (Sus scrofa) and two species of peccary, the collared peccary (Tayassu tajacu) and the white-lipped peccary (T. pecari): a phylogenetic perspective

The Suidae and the Dicotylidae (or Tayassuidae) are related mammalian families, both belonging to the artiodactyl suborder Suiformes, which diverged more than 37 million years ago. Cross-species chromosome painting was performed between the domestic pig (Sus scrofa; 2n = 38), a representative of the Suidae, and two species of the Dicotylidae: the collared peccary (Tayassu tajacu; 2n = 30) and the white-lipped peccary (T. pecari; 2n = 26). G-banded metaphase chromosomes of the two peccaries were hybridized with whole chromosome painting probes derived from domestic pig chromosomes 1-18 and X. For both peccary species, a total of 31 autosomal segments that are conserved between pig and peccary could be identified. The painting results confirm conclusions inferred from G-band analyses that the karyotypes of the collared peccary and the white-lipped peccary are largely different. The karyotypic heterogeneity of the Dicotylidae contrasts with the relative homogeneity among the karyotypes of the Suidae. For this difference between the Dicotylidae and the Suidae, a number of explanations are being postulated: 1) the extant peccaries are phylogenetically less closely related than is usually assumed; 2) the peccary genome is less stable than the genome of the pigs; and 3) special (e.g. biogeographical or biosocial) circumstances have facilitated the fixation of chromosome rearrangements in ancestral dicotylid populations.

Establishment of an R-banded rabbit karyotype nomenclature by FISH localization of 23 chromosome-specific genes on both G- and R-banded chromosomes

Direct detection of fluorescent in situ hybridization signals on R-banded chromosomes stained with propidium iodide is a rapid and efficient method for constructing cytogenetic maps for species with R-banded standard karyotypes. In this paper, our aim is to establish an R-banded rabbit karyotype nomenclature that is in total agreement with the 1981 G-banded standard nomenclature. For this purpose, we have produced new GTG- and RBG-banded mid-metaphase karyotypes and an updated version of ideograms of R-banded rabbit chromosomes. In addition, to confirm correlations between G- and R-banded chromosomes, we have defined a set of 23 rabbit BAC clones, each containing a specific gene, one marker gene per rabbit chromosome, and we have localized precisely each BAC clone by FISH on both G- and R-banded chromosomes.

A radiation hybrid map of the X-chromosome of the dog (Canis familiaris)

The dog serves as an animal model for several human diseases including X-chromosome diseases. Although the canine X-chromosome is one of the largest chromosomes in the dog, only a few markers have been mapped to it to date. Using a commercially available canine whole genome radiation hybrid (RH) panel we have localized 14 microsatellite markers, 18 genes and 13 STSs on the canine X-chromosome, extending the total number of mapped markers to 45 covering an estimated 830 cR. Out of these 45 markers, seven distinct groups of markers could be established with an average spacing of 18.8 cR(3000) and ten markers remained unlinked. Using FISH analysis, six markers could be mapped physically to the p- or q-arm of the X-chromosome. Combined with the FISH mapping, three RH groups could be assigned to the p-arm and two RH groups to the q-arm. Comparison with the human X-chromosome map revealed conserved synteny up to 234 cR (TIMP1-ALAS2-AR-IL2RG-XIST). We show here that the similarity of the canine and human X-chromosomes is the largest for any mammalian species beyond the primates.

Fourteen chromosomal localizations and an update of the cytogenetic map of the rabbit

In order to improve the informativeness of the cytogenetic map of the rabbit genome, fourteen markers were regionally mapped to individual chromosomes. The localizations comprise eleven gene loci (PRLR, GHR, HK1, ACE, TF, 18S+28S rDNA, CYP2C4, PMP2, TCRB, ALOX15 and MT1) and three microsatellite loci (Sat13, Sol33 and D1Utr6). Five of the genes contain known microsatellite sequences. To achieve these localizations, homologous and heterologous small insert clones, and clones from a rabbit Bacterial Artificial Chromosome (BAC) library were used as probes for fluorescence in situ hybridization experiments. Results indicate that especially BAC clones are a valuable tool for cytogenetic mapping. Some of the genes were selected for mapping on the basis of human- rabbit comparative painting data, to achieve localizations on gene-poor rabbit chromosomes. Our data are, in general, in agreement with the human-rabbit comparative painting data. By mapping microsatellite sequences that have also been used in linkage studies, links are provided between the genetic and physical maps of the rabbit genome. Linkage groups I, VI and XI could be assigned to chromosomes 1, 5 and 3 respectively. Moreover, in this paper we give an overview of the current status of the rabbit cytogenetic map. This map now comprises 62 physically mapped genes, which are scattered over all autosomes, except chromosome 2, and the X chromosome.

Mapping of 14 expressed sequence tags (ESTs) from porcine skeletal muscle by somatic cell hybrid analysis

Chromosomal assignments are reported for fourteen porcine expressed sequence tags (ESTs)--CALM1, CRYAB, MYH7, MYL1, PDK4, PGAM2, PYGM, REV3L, RFC1, SLN, SPTBN1, SRM160, TPM1 and YWHAG. The ESTs were derived from our porcine skeletal muscle cDNA library. The ESTs sequences selected for mapping included the presence of the 3'-untranslated region. The assignments were performed using two independent somatic cell hybrid panels providing the possibility of confirmation of the results obtained. The observed localizations are compared with the locations predicted from heterologous (human-pig, pig-human) chromosome painting data and knowledge of the map locations of the human homologues. These results add new information to the porcine genome transcript map.

Analysis of chromosome aberrations in a mammary carcinoma cell line from a dog by using canine painting probes

A cell line derived from a spleen metastasis of a mammary carcinoma in a female dog was analyzed by fluorescence in situ hybridization with canine chromosome-specific paints. The cell line showed a modal chromosome number of 77, with three (90% of the cells) or four (10% of the cells) biarmed chromosomes. Aberrations observed relate to chromosomes 8 or 11, 13 or 15, 37, 38, and X and include chromosome loss (X), formation of isochromosomes (8 or 11, 13 or 15), and centric fusion (37 and 38). In all aberrations, whole chromosomes are involved. None of the genes known to be related to breast cancer development in humans and that has mapped in the dog is located on one of the aberrant chromosomes. The results of this study show that chromosome painting is a most useful tool for the analysis of canine tumor cells.

A Pathotype System to Describe Intraspecific Variation in Pathogenicity of Meloidogyne chitwoodi

Tests of eight Dutch Meloidogyne chitwoodi isolates to the differential set for host races 1 and 2 in M. chitwoodi provided no evidence for the existence of host race 2 in the Netherlands. The data showed deviations from expected reactions on the differential hosts, which raised doubts of the usefulness of the host race classification in M. chitwoodi. The term ''pathotype'' is proposed for groups of isolates of one Meloidogyne sp. that exhibit the same level of pathogenicity on genotypes of one host species. We recommend that the pathotype classification be applied in pathogen-host relationships when several genotypes of a Meloidogyne sp. are tested on several genotypes of one host species. Three pathotypes of M. chitwoodi were identified on Solanum bulbocastanum, suggesting at least two different genetic factors for virulence and resistance in the pathogen and the host species, respectively. The occurrence of several virulence factors in M. chitwoodi will complicate the successful application of resistance factors from S. bulbocastanum for developing resistant potato cultivars.

Specific Diagnosis of Two Root-Knot Nematodes, Meloidogyne chitwoodi and M. fallax, with Satellite DNA Probes

ABSTRACT Meloidogyne chitwoodi and M. fallax are serious pests of potato, and both species have been recently designated as quarantine organisms in the European Community and in Canada. The sympatric and less damaging species M. hapla is often found associated with both of them under temperate climates. Here, we describe the use of satellite DNA (satDNA) sequences previously isolated from these three root-knot nematode species for the development of specific diagnostic procedures. In dot-blot experiments, it was unambiguously possible to separate M. chitwoodi and M. fallax from M. hapla using satDNA monomers as probes. In squash-blot experiments, satDNAs allowed discrimination between single individuals of M. chitwoodi or M. fallax from M. hapla, even within root tissues, without the need for DNA purification. The same results were obtained with radioactive or digoxigenin-labeled probes with no loss of sensitivity in detection. M. fallax and M. chitwoodi could not be distinguished. From this study, it is concluded that such cloned satDNA sequences may constitute a powerful tool for the identification and management of Meloidogyne spp. populations in the field and for the implementation of quarantine regulations against these pests.

Mapping of the Na+, K(+)-ATPase subunit alpha 2 (ATP1A2) and muscle phosphofructokinase (PFKM) genes in pig by somatic cell hybrid analysis

Two expressed sequence tags were isolated from a porcine skeletal muscle cDNA library and identified as the putative partial cDNAs of the porcine Na+, K(+)-ATPase subunit alpha 2 (ATP1A2) and muscle phosphofructokinase (PFKM) genes after sequencing and homology search. Results of analysis of a pig-rodent somatic cell hybrid panel by PCR allowed the assignments of ATP1A2 to porcine chromosome (chr) 4 and of PFKM to porcine chr 5. These assignments support previously observed conservation of syntenic relationships between human chr 1 and porcine chr 4 and between human chr 12 and porcine chr 5.

Variation in Virulence Within Meloidogyne chitwoodi, M. fallax, and M. hapla on Solanum spp

ABSTRACT The virulence of Meloidogyne hapla, M. chitwoodi, and M. fallax was studied on genotypes of Solanum spp. in a greenhouse. Juveniles of 11 M. hapla race A isolates, 3 M. hapla race B isolates, and 5 mono-female lines of a M. hapla race A isolate were inoculated on S. chacoense, S. hougasii, and S. sparsipilum. Juveniles of eight M. chitwoodi isolates, five M. fallax isolates, and six mono-female lines of a M. chitwoodi isolate were inoculated on S. bulbocastanum, S. chacoense, S. hougasii, S. stoloniferum, and S. tuberosum. Virulence was expressed as nematode reproduction 8 weeks after inoculation. Nematode reproduction was estimated by the number of egg masses and, in one experiment, by the number of hatched second-stage juveniles per inoculated juvenile. Considerable variation in virulence and resistance was observed among M. hapla isolates and plant genotypes, respectively. The M. hapla isolate-plant species interaction was highly significant. The response to M. chitwoodi ranged from susceptible (S. tuberosum and S. chacoense) to highly resistant (S. bulbocastanum and S. hougasii). S. tuberosum was susceptible to M. fallax, whereas all four wild species were resistant. In contrast to M. hapla, no significant isolate-plant genotype interaction was obtained for M. chitwoodi or M. fallax, indicating no or little intraspecific variation in virulence. M. chitwoodi juveniles in species mixtures with M. fallax isolates appeared to be able to break the resistance of S. bulbocastanum and S. hougasii. Significant differences among mono-female lines of M. hapla and M. chitwoodi were observed, indicating heterogeneity of pathogenicity within meiotic parthenogenic Meloidogyne populations.

A satellite DNA element specific for roe deer (Capreolus capreolus)

An abundant tandem repetitive DNA segment (CCsatIII) with a repeat unit of 2.2 kb has been found in the genome of roe deer (Capreolus capreolus). It accounts for approximately 5%-10% of the genome and is only present in the two species of the genus Capreolus. The sequence has no similarity or common motives with other deer satellite DNAs and there is no internal repeat structure. A 93 bp fragment is homologous to a bovine repeat. Fluorescent in situ hybridisation showed a predominant centromeric staining of most chromosomes accompanied by a weak interstitial staining of the same chromosomes. On Southern blots, CCsatIII probes do not discriminate between the closely related Capreolus species.

Localization of 18S + 28S and 5S ribosomal RNA genes in the dog by fluorescence in situ hybridization

The gene clusters encoding 18S + 28S and 5S rRNA in the dog (Canis familiaris) have been localized by using GTG-banding and fluorescence in situ hybridization. The 18S + 28S rDNA maps to chromosome regions 7q2.5-->q2.7, 17q1.7, qter of a medium-sized, not yet numbered autosome, and Yq1.2-->q1.3. Our data show that there is one cluster of 5S rDNA in the dog, which maps to chromosome region 4q1.4.

Unusual and strongly structured sequence variation in a complex satellite DNA family from the nematode Meloidogyne chitwoodi

An AluI satellite DNA family has been isolated in the genome of the root-knot nematode Meloidogyne chitwoodi. This repeated sequence was shown to be present at approximately 11,400 copies per haploid genome, and represents about 3.5% of the total genomic DNA. Nineteen monomers were cloned and sequenced. Their length ranged from 142 to 180 bp, and their A + T content was high (from 65.7 to 79.1%), with frequent runs of As and Ts. An unexpected heterogeneity in primary structure was observed between monomers, and multiple alignment analysis showed that the 19 repeats could be unambiguously clustered in six subfamilies. A consensus sequence has been deduced for each subfamily, within which the number of positions conserved is very high, ranging from 86.7% to 98.6%. Even though blocks of conserved regions could be observed, multiple alignment of the six consensus sequences did not enable the establishment of a general unambiguous consensus sequence. Screening of the six consensus sequences for evidence of internal repeated subunits revealed a 6-bp motif (AAATTT), present in both direct and inverted orientation. This motif was found up to nine times in the consensus sequences, also with the occurrence of degenerated subrepeats. Along with the meiotic parthenogenetic mode of reproduction of this nematode, such structural features may argue for the evolution of this satellite DNA family either (1) from a common ancestral sequence by amplification followed by mechanisms of sequence divergence, or (2) through independent mutations of the ancestral sequence in isolated amphimictic nematode populations and subsequent hybridization events. Overall, our results suggest the ancient origin of this satellite DNA family, and may reflect for M. chitwoodi a phylogenetic position close to the ancestral amphimictic forms of root-knot nematodes.

Localization of the 18S, 5.8S and 28S rRNA genes and the 5S rRNA genes in the babirusa and the white-lipped peccary

The locations of the genes encoding 18S, 5.8S and 28S rRNA and 5S rRNA were studied in two relatives of the domestic pig, the babirusa (Babyrousa babyrussa) and the white-lipped peccary (Tayassu pecari). In the babirusa, the 18S, 5.8S and 28S rDNA is located on chromosomes 6, 8 and 10. The genes on chromosomes 8 and 10 are actively transcribed, in contrast to those on chromosomes 6. In the white-lipped peccary, this rDNA was found to be located on chromosomes 4 and 8. The genes on both of these pairs of chromosomes are actively transcribed. The 5S rDNA was physically mapped to chromosome 16 in the babirusa, and to chromosome 11 in the white-lipped peccary. These data are compared to similar data obtained for the domestic pig, and confirm previously recognized chromosome homologies.

Construction of a cytogenetically characterized porcine somatic cell hybrid panel and its use as a mapping tool

A new panel of cytogenetically characterized pig-rodent somatic cell hybrids was constructed and tested for twelve microsatellite markers with PCR. Cytogenetic characterization of hybrids was accomplished by fluorescence painting and GTG-banding of metaphase chromosomes. The panel consists of 15 independent pig-hamster and 6 independent pig-mouse cell lines. In the panel, all pig autosomes and the X Chromosome (Chr) are represented, and it is informative for all chromosome pairs except 2-14, 2-15, 3-9, 14-15, 14-16, and 16-17. The microsatellites tested were S0022, S0023, S0084, S0098, S0112, S0113, S0114, S0115, S0117, S0118, S0119, and S0120. The PCR results obtained in the 21 hybrids were compared with the cytogenetic data and analyzed for concordancy and correlation. Eight microsatellites could be assigned to specific pig chromosomes, confirming seven assignments based on linkage analysis.

Arabidopsis thaliana expressing the cauliflower mosaic virus ORF VI transgene has a late flowering phenotype

Expression of open reading frame (ORF) VI of cauliflower mosaic virus (CaMV) in transgenic Arabidopsis thaliana caused a typical syndrome characterised by leaf chlorosis, vein clearing, plant stunting and reduced fertility. In addition and in comparison to untransformed controls we observed the formation of much larger rosettes of leaves combined with much later flowering and more extensive tillering. In these aspects, the ORF VI transgenic plants resembled late flowering mutants. All these phenotypes correlated with expression of ORF VI in three lines of transgenic plants which were produced independently, with different Ti-plasmid derived vectors and with different selective markers. The late flowering phenotype cosegregated with the transgene.

Chromosome homology between the domestic pig and the babirusa (family Suidae) elucidated with the use of porcine painting probes

Homology among three pairs of domestic pig (Sus scrofa) and five pairs of babirusa (Babyrousa babyrussa) autosomes has been demonstrated with the use of porcine painting probes. With the results of this study, in addition to data obtained earlier through the application of banding techniques, correspondence between all individual chromosomes of these two distantly related pigs has been identified.

Comparative study of pig-rodent somatic cell hybrids

The pig chromosome complement of six different types of pig-rodent hybrid cell lines was examined by means of fluorescence in situ hybridization with a porcine SINE probe. The cell lines were obtained by fusing pig lymphocytes with cells of the Chinese hamster cell lines wg3h, BK14-150 and E36, and of the mouse cell lines NSO, PU and LMTK-. The hybrids were analysed with respect to: (1) the number of pig chromosomes, (2) the type of pig chromosomes, (3) the occurrence of pig-rodent chromosome translocations, and (4) the presence of pig chromosome fragments. The results show that the number of pig chromosomes varied within and among hybrid cell lines. The pig-hamster hybrids mainly retained nontelocentric pig chromosomes, whereas the pig-mouse hybrids also retained telocentric pig chromosomes. Pig-rodent chromosome translocations were found in all types of hybrids, but the incidence was in general low. Chromosome fragments were abundant in BK14-150 hybrids, and rare in most other hybrid cell lines. It is concluded that the SINE probe is a useful tool to make a preliminary characterization of the porcine chromosome complement of pig-rodent somatic cell hybrids. The results of this characterization can be used to select hybrids for further cytogenetic analysis. Furthermore, our data show that different rodent cell lines will have to be used as fusion partners for the production of hybrids when constructing a panel informative for all pig chromosomes.

Rapid evolution of horse satellite DNA

The major satellite of the horse genome consists of about 1 million copies of a 221-bp tandem repeat unit. By fluorescence in situ hybridization it has been localized in the centromeres of 58 of the 64 horse chromosomes. The donkey genome contains a similar but not identical satellite. Strikingly, the equine repeat did not hybridize to DNA of the Grevy zebra, despite the divergence of the horse and zebra only 3 to 5 million years ago and the ability of these species to crossbreed. The evolution of satellite DNA in the Equidae is more rapid than that in other mammalian families, which may be explained by their rapid karyotypic evolution.

Cauliflower Mosaic Virus Gene VI Controls Translation from Dicistronic Expression Units in Transgenic Arabidopsis Plants

Transformed Arabidopsis plants were used to study the effect of the cauliflower mosaic virus (CaMV) inclusion body protein on translation of dicistronic RNA. Reporter plants contain a dicistronic transcription unit with CaMV open reading frame VII (ORF VII) as the first and the [beta]-glucuronidase (GUS) reporter ORF as the second cistron. "Transactivator plants" contain CaMV ORF VI under the control of the strong CaMV 35S promoter. The transactivator plants were difficult to regenerate and showed an abnormal phenotype. Expression of GUS activity in the reporter plants was very low, but high GUS activity could be induced by introduction of gene VI, either by crossing with plants containing gene VI as a transgene or by infection with CaMV. Histological GUS assays showed that transactivation occurred in all types of tissue and at all developmental stages. The practical implications of the induction of GUS expression from the dicistronic unit by virus infection are discussed.

Reproduction of the beet cyst nematode Heterodera schachtii Schm. on transformed root cultures of Beta vulgaris L

Transformed hairy root cultures of Beta vulgaris L., grown in petri-dishes, were inoculated with a suspension of surface-sterilized larvae of the beet cyst nematode Heterodera schachtii Schm. Larvae developed into both male and female adults. Juvenile larvae were hatched from the newly-formed cysts, indicating that fertilization had occurred. Results of a glasshouse test showed that H. schachtii did not lose its pathogenicity after being cultured on transformed roots. This technique can be developed further for the mass-propagation of sedentary nematodes and for the in vitro storage of isclates.