Sample records for diploidy

  1. Noncomplementing diploidy resulting from spontaneous zygogenesis in Escherichia coli. (United States)

    Gratia, Jean-Pierre


    With the aim of understanding sexual reproduction and phenotypic expression, a novel type of mating recently discovered in Escherichia coli was investigated. Termed spontaneous zygogenesis (or Z-mating), it differs from F-mediated conjugation. Its products proved phenotypically unstable, losing part of the phenotype for which they were selected. Inactivation of a parental chromosome in the zygote is strongly suggested by fluctuation tests, respreading experiments, analysis of reisolates, and segregation of non-viable cells detected by epifluorescence staining. Some phenotypically haploid subclones were interpreted as stable noncomplementing diploids carrying an inactivated co-replicating chromosome. Pedigree analysis indicated that the genetic composition of such cells consisted of parental genomes or one parental plus a recombinant genome. Inactivation of a chromosome carrying a prophage resulted in the disappearance of both the ability to produce phage particles and the immunity to superinfection. Phage production signalled transient reactivation of such a chromosome and constituted a sensitive test for stable noncomplementing diploidy. Chromosome inactivation thus appears to be a spontaneous event in bacteria.

  2. Diploidy and the selective advantage for sexual reproduction in unicellular organisms. (United States)

    Kleiman, Maya; Tannenbaum, Emmanuel


    This article develops mathematical models describing the evolutionary dynamics of both asexually and sexually reproducing populations of diploid unicellular organisms. The asexual and sexual life cycles are based on the asexual and sexual life cycles in Saccharomyces cerevisiae, Baker's yeast, which normally reproduces by asexual budding, but switches to sexual reproduction when stressed. The mathematical models consider three reproduction pathways: (1) Asexual reproduction, (2) self-fertilization, and (3) sexual reproduction. We also consider two forms of genome organization. In the first case, we assume that the genome consists of two multi-gene chromosomes, whereas in the second case, we consider the opposite extreme and assume that each gene defines a separate chromosome, which we call the multi-chromosome genome. These two cases are considered to explore the role that recombination has on the mutation-selection balance and the selective advantage of the various reproduction strategies. We assume that the purpose of diploidy is to provide redundancy, so that damage to a gene may be repaired using the other, presumably undamaged copy (a process known as homologous recombination repair). As a result, we assume that the fitness of the organism only depends on the number of homologous gene pairs that contain at least one functional copy of a given gene. If the organism has at least one functional copy of every gene in the genome, we assume a fitness of 1. In general, if the organism has l homologous pairs that lack a functional copy of the given gene, then the fitness of the organism is kappa(l). The kappa(l) are assumed to be monotonically decreasing, so that kappa(0) = 1 > kappa(1) > kappa(2) > cdots, three dots, centered > kappa(infinity) = 0. For nearly all of the reproduction strategies we consider, we find, in the limit of large N, that the mean fitness at mutation-selection balance is max{2e(-mu) - 1,0} where N is the number of genes in the haploid set of

  3. The study of mutability of RYS2 gene in diploid yeast Saccharomyces

    International Nuclear Information System (INIS)

    Chernov, Yu.O.; Gordenin, D.A.; Soldatov, S.P.; Glazer, V.M.


    More than 3000 spontaneous X-ray and ultraviolet-radiation induced mutants have been obtained by LYSD gene in haploid and diploid yeast Saccharcomyces. Mutants were selected using Chattu et cet. method. Comparison of mutant frequency in haploidy and diploidy and analysis of pho 1 marker closely related with LYS2 gene allow to conclude that the main mechanism causing spontaneous and induced mutants in diploidy is mutation of LYS2 gene in one of homologues and the following mitotic homozygotization of originating mutation

  4. Transcriptome and proteome analysis of ovaries of arrhenotokous and thelytokous Venturia canescens. (United States)

    Mateo Leach, I; Hesseling, A; Huibers, W H C; Witsenboer, H; Beukeboom, L W; van de Zande, L


    Under arrhenotoky, unfertilized haploid eggs develop as males but under thelytoky they develop into diploid females after they have undergone diploidy restoration. In the parasitoid wasp Venturia canescens both reproductive modes occur. Thelytoky is genetically determined but the underlying genetics of diploidy restoration remain unknown. In this study we aim to identify the genes and/or proteins that control thelytoky. cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis of total ovarian RNA and two-dimensional protein electrophoresis in combination with mass spectrometry revealed putative transcripts and proteins involved in arrhenotokous and thelytokous development. The detected tubulin and actin protein differences are most likely functionally related to the two types of reproduction.

  5. Computer simulation of arising of diploid genomes (United States)

    Tretyakov, Victor S.; Tretyakov, Nikolay P.


    The haploid-diploid cycle where, under unfavorable conditions the population becomes diploid, is modeled by a Monte-Carlo method in the framework of the Jan-Stauffer-Moseley hypothesis. Diploidy and sex may have first arisen as a way to escape death, when a simple unicellular individual is threatened by too many deleterious mutations. Using a bit string model, we find that in a system where competition is present (through the Verhulst factor), diploids dominate. In this case the transition from haploid to essentially diploid population takes place in a short time interval reminiscent of phase transitions in physical systems.

  6. Genetic studies with morphological mutants of Aspergillus niger

    International Nuclear Information System (INIS)

    Roy, Ponty; Das, Arati


    Three classes of coloured mutations, viz., fawn, yellow and green, occurred recurrently among the population following UV- and γ-radiation from Co 60 of a wild Aspergillus niger strain 350. Ten mutants were picked up and complementation tests were performed by growing them in pairwise combinations. In two cases, allelic mutants of the same colour were observed. All these mutants were again grown in pairwise crosses with a brown A. niger mutant of different lineage. A poor heterokaryotic growth was, however, observed in one combination which later produced a diploid heterozygous nucleus. It segregated spontaneously to develop a large variety of colonies ranging from haploidy to diploidy including aneuploids. These have been analysed genetically and the possible explanations have been given. (auth.)

  7. Process of egg formation in the female body cavity and fertilization in male eggs of Phytoseiulus persimilis (Acari: Phytoseiidae). (United States)

    Toyoshima, S; Nakamura, M; Nagahama, Y; Amano, H


    The process of egg formation in the body cavity of a phytoseiid mite, Phytoseiulus persimilis, was observed to examine fertilization of male eggs. After insemination, one of the ova at the periphery of the ovary began to expand, taking up yolk. Two pronuclei appeared in the expanded egg, located dorsally in the ovary, and yolk granules were formed gradually. After the egg became filled with yolk granules the two pronuclei fused. The egg moved via the narrow entrance at the ventral region into the oviduct, where the eggshell was formed. When the eggshell was complete, and while embryogenesis proceeded, the egg was deposited. In the meantime some ova began to expand sequentially and two joining pronuclei appeared in expanding eggs. The joining pronuclei in the first egg proved male diploidy. This is additional evidence of pseudo-arrhenotoky in this phytoseiid mite species, since the first eggs developed into males.

  8. Multipolar mitosis of tetraploid cells: inhibition by p53 and dependency on Mos. (United States)

    Vitale, Ilio; Senovilla, Laura; Jemaà, Mohamed; Michaud, Mickaël; Galluzzi, Lorenzo; Kepp, Oliver; Nanty, Lisa; Criollo, Alfredo; Rello-Varona, Santiago; Manic, Gwenola; Métivier, Didier; Vivet, Sonia; Tajeddine, Nicolas; Joza, Nicholas; Valent, Alexander; Castedo, Maria; Kroemer, Guido


    Tetraploidy can constitute a metastable intermediate between normal diploidy and oncogenic aneuploidy. Here, we show that the absence of p53 is not only permissive for the survival but also for multipolar asymmetric divisions of tetraploid cells, which lead to the generation of aneuploid cells with a near-to-diploid chromosome content. Multipolar mitoses (which reduce the tetraploid genome to a sub-tetraploid state) are more frequent when p53 is downregulated and the product of the Mos oncogene is upregulated. Mos inhibits the coalescence of supernumerary centrosomes that allow for normal bipolar mitoses of tetraploid cells. In the absence of p53, Mos knockdown prevents multipolar mitoses and exerts genome-stabilizing effects. These results elucidate the mechanisms through which asymmetric cell division drives chromosomal instability in tetraploid cells.

  9. Expression of placental protein 14 by the new endometrial cancer cell line MFE-280 in vitro and by endometrial carcinomas in vivo. (United States)

    Hackenberg, R; Loos, S; Nia, A H; Kunzmann, R; Schulz, K D


    MFE-280 endometrial cancer cells express PP14 (placental protein 14) in vitro. PP14 is normally found in the secretory endometrium and in placental tissue. MFE-280 cells, which are tumorigenic in nude mice, were derived from a recurrent, poorly differentiated endometrial carcinoma. The cells were initially grown in suspension culture and later transferred to monolayer cultures. Karyotyping revealed near-diploidy with a complex heterogeneous aberration pattern. MFE-280 cells were positive for the cytokeratins 7, 8, 18 and 19 as well as for vimentin. The expression of PP14 in MFE-280 cells was demonstrated by immunochemistry and reverse transcriptase--polymerase chain reaction. PP14-mRNA was also detected in one out of five endometrial cancer specimen. In tumor tissue the expression of PP14 was not dependent on progestins.

  10. Diagnostic reproducibility of hydatidiform moles: ancillary techniques (p57 immunohistochemistry and molecular genotyping) improve morphologic diagnosis for both recently trained and experienced gynecologic pathologists. (United States)

    Gupta, Mamta; Vang, Russell; Yemelyanova, Anna V; Kurman, Robert J; Li, Fanghong Rose; Maambo, Emily C; Murphy, Kathleen M; DeScipio, Cheryl; Thompson, Carol B; Ronnett, Brigitte M


    Distinction of hydatidiform moles from nonmolar specimens (NMs) and subclassification of hydatidiform moles as complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) are important for clinical practice and investigational studies; however, diagnosis based solely on morphology is affected by interobserver variability. Molecular genotyping can distinguish these entities by discerning androgenetic diploidy, diandric triploidy, and biparental diploidy to diagnose CHMs, PHMs, and NMs, respectively. Eighty genotyped cases (27 CHMs, 27 PHMs, 26 NMs) were selected from a series of 200 potentially molar specimens previously diagnosed using p57 immunohistochemistry and genotyping. Cases were classified by 6 pathologists (3 faculty level gynecologic pathologists and 3 fellows) on the basis of morphology, masked to p57 immunostaining and genotyping results, into 1 of 3 categories (CHM, PHM, or NM) during 2 diagnostic rounds; a third round incorporating p57 immunostaining results was also conducted. Consensus diagnoses (those rendered by 2 of 3 pathologists in each group) were also determined. Performance of experienced gynecologic pathologists versus fellow pathologists was compared, using genotyping results as the gold standard. Correct classification of CHMs ranged from 59% to 100%; there were no statistically significant differences in performance of faculty versus fellows in any round (P-values of 0.13, 0.67, and 0.54 for rounds 1 to 3, respectively). Correct classification of PHMs ranged from 26% to 93%, with statistically significantly better performance of faculty versus fellows in each round (P-values of 0.04, <0.01, and <0.01 for rounds 1 to 3, respectively). Correct classification of NMs ranged from 31% to 92%, with statistically significantly better performance of faculty only in round 2 (P-values of 1.0, <0.01, and 0.61 for rounds 1 to 3, respectively). Correct classification of all cases combined ranged from 51% to 75% by morphology and 70% to 80

  11. Diagnostic reproducibility of hydatidiform moles: ancillary techniques (p57 immunohistochemistry and molecular genotyping) improve morphologic diagnosis. (United States)

    Vang, Russell; Gupta, Mamta; Wu, Lee-Shu-Fune; Yemelyanova, Anna V; Kurman, Robert J; Murphy, Kathleen M; Descipio, Cheryl; Ronnett, Brigitte M


    Distinction of hydatidiform moles (HMs) from nonmolar specimens (NMs) and subclassification of HMs as complete hydatidiform moles (CHMs) and partial hydatidiform moles (PHMs) are important for clinical practice and investigational studies; yet, diagnosis based solely on morphology is affected by interobserver variability. Molecular genotyping can distinguish these entities by discerning androgenetic diploidy, diandric triploidy, and biparental diploidy to diagnose CHMs, PHMs, and NMs, respectively. Eighty genotyped cases (27 CHMs, 27 PHMs, and 26 NMs) were selected from a series of 200 potentially molar specimens previously diagnosed using p57 immunostaining and genotyping. Cases were classified by 3 gynecologic pathologists on the basis of H&E slides (masked to p57 immunostaining and genotyping results) into 1 of 3 categories (CHM, PHM, or NM) during 2 diagnostic rounds; a third round incorporating p57 immunostaining results was also conducted. Consensus diagnoses (those rendered by 2 of 3 pathologists) were determined. Genotyping results were used as the gold standard for assessing diagnostic performance. Sensitivity of a diagnosis of CHM ranged from 59% to 100% for individual pathologists and from 70% to 81% by consensus; specificity ranged from 91% to 96% for individuals and from 94% to 98% by consensus. Sensitivity of a diagnosis of PHM ranged from 56% to 93% for individual pathologists and from 70% to 78% by consensus; specificity ranged from 58% to 92% for individuals and from 74% to 85% by consensus. The percentage of correct classification of all cases by morphology ranged from 55% to 75% for individual pathologists and from 70% to 75% by consensus. The κ values for interobserver agreement ranged from 0.59 to 0.73 (moderate to good) for a diagnosis of CHM, from 0.15 to 0.43 (poor to moderate) for PHM, and from 0.13 to 0.42 (poor to moderate) for NM. The κ values for intraobserver agreement ranged from 0.44 to 0.67 (moderate to good). Addition of the p57

  12. Cytogenetic study of murine rodents inhabiting in uranium-mining regions of Akmolinskaya oblast

    International Nuclear Information System (INIS)

    Kazymbet, P.; Altaeva, N.; Bakhtin, M.; Zhapbasov, R.


    Republic of Kazakhstan is ranked as the world's leading uranium ore reserves. About 25% of the world's proven uranium ore reserves occur here. Strategy of study concerning ecology effects conditioned by ionizing radiation includes as one main element an analysis of genetic processes in natural populations and ecosystems. Therefore analysis of cytogenetic effects of murine rodents inhabiting in influence zones of uranium-mining regions is one of the most important elements of radio-bio-ecological monitoring and are not completed so far. In habitat of murine rodents in influence zone of Stepnogorsk Mining-Chemical Complex tailing it is shown that gamma radiation equivalent dose rate and beta-particle flux density exceed from 6 to 15 times check measurements. In soil, plant, and water samples the activity of radionuclides like 238 U, 226 Ra, 232 Th and 210 Pb exceeds the testing level from 2 to 52 times. Dose of ionizing radiation absorbed by murine rodents inhabited in radioactive contaminated areas exceeds from 10 to 19 times the one absorbed by control animals. Big Jerboa (Allactaga major Kern) inhabited nearby of Stepnogorsk Mining-Chemical Complex tailing has rate of occurrence of cells with hypo diploidy, and hyper diploidy in hematopoietic tissue which correspondingly 1,85 and 3,5 times exceeds the control level; and this factor of Jerboa (Allactaga saltator Eversman) is correspondingly 1,7 and 4,1 times higher than control level. Rate of occurrence of cells with polyploidy in Big Jerboa (Allactaga major Kern) from radioactively contaminated areas is 2,7 times higher than in control animal; and this factor of Jerboa (Allactaga saltator Eversman) by 6,4 times exceeds control level. Levels of chromosomal rearrangements of Big Jerboa (Allactaga major Kern) from trail and control areas are 3,39±0,60% and 0,60±0,19% correspondently; and these factors of Jerboa (Allactaga saltator Eversman) are 4,63±0,91% and 1,22±0,37%, correspondently which confirms existence

  13. der(4)t(Y;4): Three-generation transmission and sperm meiotic segregation analysis. (United States)

    Vozdova, Miluse; Horinova, Vera; Wernerova, Vendula; Skalikova, Romana; Rybar, Roman; Prinosilova, Petra; Oracova, Eva; Rubes, Jiri


    We present a family where five members (three males and two females) are carriers of der(4)t(Y;4)(q11.23;p16.3). The adult carriers are phenotypicaly normal and fertile; the boy shows macrocephaly, psychomotor retardation, and atypical autism. The FISH on cultured lymphocytes confirmed that the redundant Yq heterochromatin was attached to the 4p-subtelomeric region maintained on the der(4). Sperm FISH analysis performed in a normospermic der(4) carrier showed a significant distortion of the expected 1:1 ratio of the X- and Y-bearing spermatozoa in favor of the X chromosome and significant lack of Y,der(4)spermatozoa. The overall lack of Y spermatozoa was not balanced even by a relative excess of Y,4 sperm. The analysis of X, Y, 7, 8, 18, and 21 sperm disomy and diploidy did not indicate any interchromosomal effect. The chromosome 4 disomy was significantly increased but still very low to be of considerable reproductive significance. The neurodevelomental phenotype of the boy was probably caused by a gene mutation. The coincidental occurrence of such chromosomal aberration and boy's phenotype might lead to misinterpretation of the causal relationship between these findings. It is necessary to consider the results of chromosomal analysis and clinical records of relatives for provide genetic counseling in such families. Copyright © 2011 Wiley-Liss, Inc.

  14. Patterns of homoeologous gene expression shown by RNA sequencing in hexaploid bread wheat.

    KAUST Repository

    Leach, Lindsey J; Belfield, Eric J; Jiang, Caifu; Brown, Carly; Mithani, Aziz; Harberd, Nicholas P


    BACKGROUND: Bread wheat (Triticum aestivum) has a large, complex and hexaploid genome consisting of A, B and D homoeologous chromosome sets. Therefore each wheat gene potentially exists as a trio of A, B and D homoeoloci, each of which may contribute differentially to wheat phenotypes. We describe a novel approach combining wheat cytogenetic resources (chromosome substitution 'nullisomic-tetrasomic' lines) with next generation deep sequencing of gene transcripts (RNA-Seq), to directly and accurately identify homoeologue-specific single nucleotide variants and quantify the relative contribution of individual homoeoloci to gene expression. RESULTS: We discover, based on a sample comprising ~5-10% of the total wheat gene content, that at least 45% of wheat genes are expressed from all three distinct homoeoloci. Most of these genes show strikingly biased expression patterns in which expression is dominated by a single homoeolocus. The remaining ~55% of wheat genes are expressed from either one or two homoeoloci only, through a combination of extensive transcriptional silencing and homoeolocus loss. CONCLUSIONS: We conclude that wheat is tending towards functional diploidy, through a variety of mechanisms causing single homoeoloci to become the predominant source of gene transcripts. This discovery has profound consequences for wheat breeding and our understanding of wheat evolution.

  15. Número de alelos XO em uma população de Melipona quadrifasciata anthidioides Lepeletier (Hymenoptera, Apidae, Meliponinae Number of XO alleles in a population of Melipona quadrifasciata anthidioides Lepeletier (Hymenoptera, Apidae, Meliponinae

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    Davi S. Aidar


    Full Text Available The number of xo alleles of a population of stingless bees can be estimated by observing the male proportion of the first brood comb produced by a new queen (about 40 Fl bees and the total number of colonies. A proportion of 50% diploid males indicates insemination of the queen by a single male with some xo sex allele: 25% diploid male would indicate insemination by two males (one with some xo as the queen and another with different one. Diploidy was confirmed by cytology of the testis. The original population (78 colonies of Ribeirão Preto, State S. Paulo, Brazil, had 8 xo sex alleles. From this population, 10 colonies were orphaned and taken to the Serra do Mar (Sea Mountains at Espirito Santo State (1200 km far in order that the virgin queen of each colony would cross with males of this region. Ten days after the nine hives (one was lost were brought back to Ribeirão Preto. No one of them produced diploid males. New samples took from all the Meliponary revealed that the number of xo sex alleles to have increased to 17,3. Than, this methodology can be used to increase the genetic variability of the stingless bees populations.

  16. Diploid Male Production of Two Amazonian Melipona Bees (Hymenoptera: Apidae

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    Izaura Bezerra Francini


    Full Text Available The diploid male has already been recorded for Melipona Illger, and herein, in Melipona seminigra merrillae Cockerell and Melipona interrupta manaosensis Schwarz. This paper was carried out at the Instituto Nacional de Pesquisas da Amazônia (INPA, Manaus, AM, Brazil. We produced and monitored 31 new colonies of M. s. merrillae and 32 new colonies of M. i. manaosensis. We sampled 2,995 pupae of M. s. merrillae and 2,020 of M. i. manaosensis. In colonies with a 1 : 1 sex ratio, male diploidy was confirmed by cytogenetic analysis and workers’ behavior. We estimated 16 sex-determining alleles in M. s. merrillae and 22 in M. i. manaosensis. In colonies of M. i. manaosensis in a 1 : 1 sex ratio, workers killed the males and the queen that produced them soon after they emerged, as predicted. This behavior was not registered for M. s. merrillae, and sex ratios did not stay 1 : 1, indicating polyandry for this species.

  17. Parasitic Cape honeybee workers, Apis mellifera capensis, evade policing (United States)

    Martin, Stephen J.; Beekman, Madeleine; Wossler, Theresa C.; Ratnieks, Francis L. W.


    Relocation of the Cape honeybee, Apis mellifera capensis, by bee-keepers from southern to northern South Africa in 1990 has caused widespread death of managed African honeybee, A. m. scutellata, colonies. Apis mellifera capensis worker bees are able to lay diploid, female eggs without mating by means of automictic thelytoky (meiosis followed by fusion of two meiotic products to restore egg diploidy), whereas workers of other honeybee subspecies are able to lay only haploid, male eggs. The A. m. capensis workers, which are parasitizing and killing A. m. scutellata colonies in northern South Africa, are the asexual offspring of a single, original worker in which the small amount of genetic variation observed is due to crossing over during meiosis (P. Kryger, personal communication). Here we elucidate two principal mechanisms underlying this parasitism. Parasitic A. m. capensis workers activate their ovaries in host colonies that have a queen present (queenright colonies), and they lay eggs that evade being killed by other workers (worker policing)-the normal fate of worker-laid eggs in colonies with a queen. This unique parasitism by workers is an instance in which a society is unable to control the selfish actions of its members.

  18. Meta-analysis of the predictive value of DNA aneuploidy in malignant transformation of oral potentially malignant disorders. (United States)

    Alaizari, Nader A; Sperandio, Marcelo; Odell, Edward W; Peruzzo, Daiane; Al-Maweri, Sadeq A


    DNA aneuploidy is an imbalance of chromosomal DNA content that has been highlighted as a predictor of biological behavior and risk of malignant transformation. To date, DNA aneuploidy in oral potentially malignant diseases (OPMD) has been shown to correlate strongly with severe dysplasia and high-risk lesions that appeared non-dysplastic can be identified by ploidy analysis. Nevertheless, the prognostic value of DNA aneuploidy in predicting malignant transformation of OPMD remains to be validated. The aim of this meta-analysis was to assess the role of DNA aneuploidy in predicting malignant transformation in OPMD. The questions addressed were (i) Is DNA aneuploidy a useful marker to predict malignant transformation in OPMD? (ii) Is DNA diploidy a useful negative marker of malignant transformation in OPMD? These questions were addressed using the PECO method. Five studies assessing aneuploidy as a risk marker of malignant change were pooled into the meta-analysis. Aneuploidy was found to be associated with a 3.12-fold increased risk to progress into cancer (RR=3.12, 95% CI 1.86-5.24). Based on the five studies meta-analyzed, "no malignant progression" was more likely to occur in DNA diploid OPMD by 82% when compared to aneuploidy (RR=0.18, 95% CI 0.08-0.41). In conclusion, aneuploidy is a useful marker of malignant transformation in OPMD, although a diploid result should be interpreted with caution. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Autotetraploid cell Line induced by SP600125 from crucian carp and its developmental potentiality (United States)

    Zhou, Yonghua; Wang, Mei; Jiang, Minggui; Peng, Liangyue; Wan, Cong; Liu, Jinhui; Liu, Wenbin; Zhao, Rurong; Zhao, Xiaoyang; Hu, Wei; Liu, Shaojun; Xiao, Yamei


    Polyploidy has many advantages over diploidy, such as rapid growth, sterility, and disease resistance, and has been extensively applied in agriculture and aquaculture. Though generation of new polyploids via polyploidization has been achieved in plants by different ways, it is comparatively rare in animals. In this article, by a chemical compound, SP600125, polyploidization is induced in fish cells in vitro, and a stable autotetraploid cell line has been generated from diploid fibroblast cells of crucian carp. As a c-Jun N-terminal kinase (Jnk) inhibitor, SP600125 does not function during the induction process of polyploidization. Instead, the p53 signal pathway might be involved. Using the SP600125-induced tetraploid cells and eggs of crucian carp as the donors and recipients, respectively, nuclear transplantation was conducted such that tetraploid embryos were obtained. It suggests that combining polyploidization and the somatic cell nuclear transfer technique (SCNT) is an efficient way to generate polyploidy, and the presented method in this research for generating the tetraploid fish from diploid fish can provide a useful platform for polyploid breeding. PMID:26898354

  20. Experimental Evolution Reveals Interplay between Sch9 and Polyploid Stability in Yeast.

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    Yi-Jin Lu


    Full Text Available Polyploidization has crucial impacts on the evolution of different eukaryotic lineages including fungi, plants and animals. Recent genome data suggest that, for many polyploidization events, all duplicated chromosomes are maintained and genome reorganizations occur much later during evolution. However, newly-formed polyploid genomes are intrinsically unstable and often quickly degenerate into aneuploidy or diploidy. The transition between these two states remains enigmatic. In this study, laboratory evolution experiments were conducted to investigate this phenomenon. We show that robust tetraploidy is achieved in evolved yeast cells by increasing the abundance of Sch9-a protein kinase activated by the TORC1 (Target of Rapamycin Complex 1 and other signaling pathways. Overexpressing SCH9, but not TOR1, allows newly-formed tetraploids to exhibit evolved phenotypes and knocking out SCH9 diminishes the evolved phenotypes. Furthermore, when cells were challenged with conditions causing ancestral cells to evolve aneuploidy, tetraploidy was maintained in the evolved lines. Our results reveal a determinant role for Sch9 during the early stage of polyploid evolution.

  1. New and emerging prognostic and predictive genetic biomarkers in B-cell precursor acute lymphoblastic leukemia (United States)

    Moorman, Anthony V.


    Acute lymphoblastic leukemia (ALL) is a heterogeneous disease at the genetic level. Chromosomal abnormalities are used as diagnostic, prognostic and predictive biomarkers to provide subtype, outcome and drug response information. t(12;21)/ETV6-RUNX1 and high hyper-diploidy are good-risk prognostic biomarkers whereas KMT2A (MLL) translocations, t(17;19)/TCF3-HLF, haploidy or low hypodiploidy are high-risk biomarkers. t(9;22)/BCR-ABL1 patients require targeted treatment (imatinib/dasatinib), whereas iAMP21 patients achieve better outcomes when treated intensively. High-risk genetic biomarkers are four times more prevalent in adults compared to children. The application of genomic technologies to cases without an established abnormality (B-other) reveals copy number alterations which can be used either individually or in combination as prognostic biomarkers. Transcriptome sequencing studies have identified a network of fusion genes involving kinase genes - ABL1, ABL2, PDGFRB, CSF1R, CRLF2, JAK2 and EPOR. In vitro and in vivo studies along with emerging clinical observations indicate that patients with a kinase-activating aberration may respond to treatment with small molecular inhibitors like imatinib/dasatinib and ruxolitinib. Further work is required to determine the true frequency of these abnormalities across the age spectrum and the optimal way to incorporate such inhibitors into protocols. In conclusion, genetic biomarkers are playing an increasingly important role in the management of patients with ALL. PMID:27033238

  2. p53 Dependent Centrosome Clustering Prevents Multipolar Mitosis in Tetraploid Cells (United States)

    Yi, Qiyi; Zhao, Xiaoyu; Huang, Yun; Ma, Tieliang; Zhang, Yingyin; Hou, Heli; Cooke, Howard J.; Yang, Da-Qing; Wu, Mian; Shi, Qinghua


    Background p53 abnormality and aneuploidy often coexist in human tumors, and tetraploidy is considered as an intermediate between normal diploidy and aneuploidy. The purpose of this study was to investigate whether and how p53 influences the transformation from tetraploidy to aneuploidy. Principal Findings Live cell imaging was performed to determine the fates and mitotic behaviors of several human and mouse tetraploid cells with different p53 status, and centrosome and spindle immunostaining was used to investigate centrosome behaviors. We found that p53 dominant-negative mutation, point mutation, or knockout led to a 2∼ 33-fold increase of multipolar mitosis in N/TERT1, 3T3 and mouse embryonic fibroblasts (MEFs), while mitotic entry and cell death were not significantly affected. In p53-/- tetraploid MEFs, the ability of centrosome clustering was compromised, while centrosome inactivation was not affected. Suppression of RhoA/ROCK activity by specific inhibitors in p53-/- tetraploid MEFs enhanced centrosome clustering, decreased multipolar mitosis from 38% to 20% and 16% for RhoA and ROCK, respectively, while expression of constitutively active RhoA in p53+/+ tetraploid 3T3 cells increased the frequency of multipolar mitosis from 15% to 35%. Conclusions p53 could not prevent tetraploid cells entering mitosis or induce tetraploid cell death. However, p53 abnormality impaired centrosome clustering and lead to multipolar mitosis in tetraploid cells by modulating the RhoA/ROCK signaling pathway. PMID:22076149

  3. Patterns of homoeologous gene expression shown by RNA sequencing in hexaploid bread wheat.

    KAUST Repository

    Leach, Lindsey J


    BACKGROUND: Bread wheat (Triticum aestivum) has a large, complex and hexaploid genome consisting of A, B and D homoeologous chromosome sets. Therefore each wheat gene potentially exists as a trio of A, B and D homoeoloci, each of which may contribute differentially to wheat phenotypes. We describe a novel approach combining wheat cytogenetic resources (chromosome substitution \\'nullisomic-tetrasomic\\' lines) with next generation deep sequencing of gene transcripts (RNA-Seq), to directly and accurately identify homoeologue-specific single nucleotide variants and quantify the relative contribution of individual homoeoloci to gene expression. RESULTS: We discover, based on a sample comprising ~5-10% of the total wheat gene content, that at least 45% of wheat genes are expressed from all three distinct homoeoloci. Most of these genes show strikingly biased expression patterns in which expression is dominated by a single homoeolocus. The remaining ~55% of wheat genes are expressed from either one or two homoeoloci only, through a combination of extensive transcriptional silencing and homoeolocus loss. CONCLUSIONS: We conclude that wheat is tending towards functional diploidy, through a variety of mechanisms causing single homoeoloci to become the predominant source of gene transcripts. This discovery has profound consequences for wheat breeding and our understanding of wheat evolution.

  4. UV-induced mitotic co-segregation of genetic markers in Candida albicans: Evidence for linkage

    International Nuclear Information System (INIS)

    Crandall, M.


    Parasexual genetic studies of the medically important yeast Candida albicans were performed using the method of UV-induced mitotic segregation. UV-irradiation of the Hoffmann-La Roche type culture of C. albicans yielded a limited spectrum of mutants at a relatively high fequency. This observation suggested natural heterozygosity. Canavanine-sensitive (CanS) segregants were induced at a frequency of 7.6 . 10 -3 . Double mutants that were both CanS and methionine (Met - ) auxotrophs were induced at a frequency of 7.4 . 10 -3 . The single Met - segregant class was missing indicating linkage. UV-induced CanS or Met - CanS segregants occurred occasionally in twin-sectored colonies. Analyses of the sectors as well as the observed and missing classes of segregants indicated that genes met and can are linked in the cis configuration. The proposed gene order is: centromere - met - can. Thus, it is concluded that the Hoffmann-La Roche strain of C. albicans is naturally heterozygous at two linked loci. These findings are consistent with diploidy. (orig.)

  5. The Chromosomal Constitution of Embryos Arising from Monopronuclear Oocytes in Programmes of Assisted Reproduction

    Directory of Open Access Journals (Sweden)

    Bernd Rosenbusch


    Full Text Available The assessment of oocytes showing only one pronucleus during assisted reproduction is associated with uncertainty. A compilation of data on the genetic constitution of different developmental stages shows that affected oocytes are able to develop into haploid, diploid, and mosaic embryos with more or less complex chromosomal compositions. In the majority of cases (~80%, haploidy appears to be caused by gynogenesis, whereas parthenogenesis or androgenesis is less common. Most of the diploid embryos result from a fertilization event involving asynchronous formation of the two pronuclei or pronuclear fusion at a very early stage. Uniparental diploidy may sometimes occur if one pronucleus fails to develop and the other pronucleus already contains a diploid genome or alternatively a haploid genome undergoes endoreduplication. In general, the chance of obtaining a biparental diploid embryo appears higher after conventional in vitro fertilization than after intracytoplasmic sperm injection. If a transfer of embryos obtained from monopronuclear oocytes is envisaged, it should be tried to culture them up to the blastocyst since most haploid embryos are not able to reach this stage. Comprehensive counselling of patients on potential risks is advisable before transfer and a preimplantation genetic diagnosis could be offered if available.

  6. Diploid yeast cells yield homozygous spontaneous mutations (United States)

    Esposito, M. S.; Bruschi, C. V.; Brushi, C. V. (Principal Investigator)


    A leucine-requiring hybrid of Saccharomyces cerevisiae, homoallelic at the LEU1 locus (leu1-12/leu1-12) and heterozygous for three chromosome-VII genetic markers distal to the LEU1 locus, was employed to inquire: (1) whether spontaneous gene mutation and mitotic segregation of heterozygous markers occur in positive nonrandom association and (2) whether homozygous LEU1/LEU1 mutant diploids are generated. The results demonstrate that gene mutation of leu1-12 to LEU1 and mitotic segregation of heterozygous chromosome-VII markers occur in strong positive nonrandom association, suggesting that the stimulatory DNA lesion is both mutagenic and recombinogenic. In addition, genetic analysis of diploid Leu+ revertants revealed that approximately 3% of mutations of leu1-12 to LEU1 result in LEU1/LEU1 homozygotes. Red-white sectored Leu+ colonies exhibit genotypes that implicate post-replicational chromatid breakage and exchange near the site of leu1-12 reversion, chromosome loss, and subsequent restitution of diploidy, in the sequence of events leading to mutational homozygosis. By analogy, diploid cell populations can yield variants homozygous for novel recessive gene mutations at biologically significant rates. Mutational homozygosis may be relevant to both carcinogenesis and the evolution of asexual diploid organisms.

  7. Cytogeography of essential oil chemotypes of Eremophila longifolia F. Muell (Scrophulariaceae). (United States)

    Sadgrove, Nicholas John; Jones, Graham Lloyd


    Previous studies have demonstrated that the widely distributed desert plant Eremophila longifolia has at least six geographically defined essential oil chemotypes. The focus of the present study is to extend and enhance information concerning known chemotypes and to investigate the involvement of cell nuclei ploidy in this variation. Forty field collected specimens of E. longifolia were taken from most of the mainland states of Australia then subjected to hydrodistillation to produce essential oils, which were then chemically characterised. Ploidy was determined using relative fluorescence of cell nuclei stained with propidium iodide, measured in a flow cytometer. Using principal component analysis (PCA), at least three essential oil chemotypes, in addition to the six already described, were identified in the present study. Previously described high yielding essential oil chemotypes were also characterised in terms of diploidy. For the first time diploid populations were identified in New South Wales, correlating with high yielding isomenthone/menthone and karahanaenone chemotypes. Furthermore, the separate diploid population previously described from Western Australia was demonstrated to be the safrole/methyl eugenol type, which is restricted to a small geographic range in far north-west Western Australia (Murchison District). All other chemotypes were shown to be tetraploid, including apparently randomly emerging individuals, representative of chemotypes producing low yields of isomenthone/menthone and karahanaenone similar in composition to the high yielding diploid types. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Immortalization of MEF is characterized by the deregulation of specific miRNAs with potential tumor suppressor activity. (United States)

    Rizzo, Milena; Evangelista, Monica; Simili, Marcella; Mariani, Laura; Pitto, Letizia; Rainaldi, Giuseppe


    The life span (Hayflick limit) of primary mouse embryo fibroblasts (MEF) in culture is variable but it is still unclear if the escape of the Hayflick limit is also variable. To address this point MEF were expanded every fifteen days (6T15) instead of every three days (6T3) until they became immortal. With this protocol MEF lifespan was extended and immortalization accordingly delayed. By testing a panel of genes (p19ARF, p16, p21) and miRNAs (miR-20a, miR-21, miR-28, miR-290) related to primary MEF senescence, a switch of p21 from up to down regulation, the down regulation of specific miRNAs as well as a massive shift from diploidy to hyperdiploidy were observed in coincidence with the resumption of cell proliferation. Collectively, these data indicate that the inactivation of genes and miRNAs, important in controlling cell proliferation, might be determinant for the escape from the Hayflick limit. In support of this hypothesis was the finding that some of the down regulated miRNAs transfected in immortalized MEF inhibited cell proliferation thus displaying a tumor suppressor-like activity.

  9. Fluorescence in situ hybridization and molecular studies in infertile men with dysplasia of the fibrous sheath. (United States)

    Baccetti, Baccio; Collodel, Giulia; Gambera, Laura; Moretti, Elena; Serafini, Francesca; Piomboni, Paola


    To perform fluorescence in situ hybridization (FISH) and molecular analysis in patients with the genetic sperm defect "dysplasia of the fibrous sheath" (DFS). Retrospective study. Regional Referral Center for Male Infertility, Siena, Italy. Twelve infertile patients with DFS sperm defects. Family history, lymphocytic karyotype, physical and hormonal assays, semen analysis. The DFS sperm phenotype was defined by light, fluorescent, and electron microscopy. Sperm chromosomal constitution was examined by FISH. Gene deletions were tested by polymerase chain reaction. The genetic sperm defect DFS was determined by transmission and scanning electron microscopy. Immunofluorescence staining of A-kinase anchoring protein 4 (AKAP4) showed a moderate and diffuse signal, revealing a disorganized and incompletely assembled fibrous sheath. In 11 of 12 DFS patients, polymerase chain reaction for detecting the presence of partial sequence of AKAP4/AKAP3 binding regions gave positive results. Fluorescence in situ hybridization was performed in decondensed sperm nuclei with probes for chromosomes 18, X, and Y. The mean disomy frequency of chromosome 18 was in the normal range, whereas the mean disomy frequencies of sex chromosomes and diploidies were twice those of controls. These results should be considered when DFS sperm are used in assisted reproductive technology, owing to the high risk of transmission of chromosomal unbalance and of DFS sperm defects to male offspring.

  10. Infertile spermatozoa in a human carrier of robertsonian translocation 14;22. (United States)

    Baccetti, Baccio; Capitani, Serena; Collodel, Giulia; Estenoz, Mariela; Gambera, Laura; Piomboni, Paola


    To present the ultrastructural, functional, and chromosomal analyses of spermatozoa from an infertile man with normal phenotype and chromosomal translocation 14;22. Case report. Regional Reference Center for Male Infertility in Siena, Italy. A 36-year-old man with primary infertility for 3 years and his parents. Family history and lymphocytic karyotypes, physical and hormonal assays, and semen analysis. Morphological sperm evaluation was performed by light, fluorescent, and electron microscopy; chromosomal constitution was examined by the fluorescence in situ hybridization (FISH) technique. The penetration ability of spermatozoa was checked by the hamster test. The spermatozoa of the patient showed unusual ultrastructural defects. The nuclei were large, spheroidal, and generally uncondensed; the acrosomes were frequently absent or reduced; and the axonemes were often devoid of dynein arms or central singlet tubules. These characteristics are related to immaturity. The lymphocytic karyotype revealed a robertsonian translocation 14;22 in the sterile patient and his mother. FISH sperm analysis demonstrated a high frequency of diploidy for the chromosome 18,XY. The hamster penetration test gave negative results. The unusual structural sperm immaturity is associated with the translocation 14;22. This chromosomal anomaly may therefore negatively influence the spermatogenesis; an interchromosomal effect on meiosis segregation is also suggested.

  11. Studies on varicocele III: ultrastructural sperm evaluation and 18, X and Y aneuploidies. (United States)

    Baccetti, Baccio M; Bruni, Emanuele; Capitani, Serena; Collodel, Giulia; Mancini, Stefano; Piomboni, Paola; Moretti, Elena


    The idea that varicocele plays a detrimental role in fertility is supported by the presence of a higher frequency of affected men among the infertile population than among men with normal semen parameters. In this research we examined ejaculates from a large group of selected men affected by varicocele by light and electron microscopy. The effect of varicocele on chromosome meiotic segregation was investigated by fluorescence in situ hybridization (FISH). The potential benefits of varicocelectomy on sperm quality were evaluated by analyzing sperm characteristics before and after surgical correction of varicocele. Transmission electron microscopy (TEM) analysis, elaborated previously, showed that the incidence of immaturity, apoptosis, and necrosis was higher in the varicocele group than in controls. FISH analysis performed on sperm nuclei from selected patients with varicocele showed that the mean frequencies of disomies and diploidies were generally out of the normal range, indicating a severe disturbance in meiotic segregation. Sperm characteristics evaluated before and after varicocele repair showed a general improvement. As a consequence, the varicocele seem to affect sperm morphology and function concomitantly with meiotic segregation derangement. In consideration of these data, we suggest that TEM and FISH analyses should be performed for all varicocele patients.

  12. Biological dosimetric studies in the Chernobyl radiation accident, on populations living in the contaminated areas (Gomel regions) and in Estonian clean-up workers, using FISH technique

    International Nuclear Information System (INIS)

    Darroudi, F.; Natarajan, A.T.


    In order to perform retrospective estimations of radiation doses seven years after the nuclear accident in Chernobyl, the frequencies of chromosomal aberrations in the peripheral blood lymphocytes of individuals living in contaminated areas around Chernobyl and the Estonian clean-up workers were determined. The first study group composed of 45 individuals living in four areas (i.e. Rechitsa, Komsomolski, Choiniki and Zaspa) in the vicinity (80-125 km) of Chernobyl and 20 individuals living in Minsk (control group - 340 km from Chernobyl). The second study group (Estonian clean-up workers) composed of 26 individuals involved in cleaning up the Chernobyl for a different period of time (up to 7 months) and a matched control group consisting of 9 probands. Unstable aberrations (dicentrics and rings) were scored in Giemsa stained preparations and stable aberrations (translocations) were analyzed using chromosome specific DNA libraries and fluorescence in situ hybridization (FISH) technique. For both study groups the estimated average dose is between 0,1-0,4 Gy. Among the people living in the contaminated areas in the vicinity of Chernobyl, a higher frequency of numerical aberrations (i.e. trisomy, hyper diploidy) was evident

  13. The neonatal marmoset monkey ovary is very primitive exhibiting many oogonia (United States)

    Fereydouni, B; Drummer, C; Aeckerle, N; Schlatt, S; Behr, R


    Oogonia are characterized by diploidy and mitotic proliferation. Human and mouse oogonia express several factors such as OCT4, which are characteristic of pluripotent cells. In human, almost all oogonia enter meiosis between weeks 9 and 22 of prenatal development or undergo mitotic arrest and subsequent elimination from the ovary. As a consequence, neonatal human ovaries generally lack oogonia. The same was found in neonatal ovaries of the rhesus monkey, a representative of the old world monkeys (Catarrhini). By contrast, proliferating oogonia were found in adult prosimians (now called Strepsirrhini), which is a group of ‘lower’ primates. The common marmoset monkey (Callithrix jacchus) belongs to the new world monkeys (Platyrrhini) and is increasingly used in reproductive biology and stem cell research. However, ovarian development in the marmoset monkey has not been widely investigated. Herein, we show that the neonatal marmoset ovary has an extremely immature histological appearance compared with the human ovary. It contains numerous oogonia expressing the pluripotency factors OCT4A, SALL4, and LIN28A (LIN28). The pluripotency factor-positive germ cells also express the proliferation marker MKI67 (Ki-67), which has previously been shown in the human ovary to be restricted to premeiotic germ cells. Together, the data demonstrate the primitiveness of the neonatal marmoset ovary compared with human. This study may introduce the marmoset monkey as a non-human primate model to experimentally study the aspects of primate primitive gonad development, follicle assembly, and germ cell biology in vivo. PMID:24840529

  14. Induced mitotic gynogenesis in common carp (Cyprinus carpio L.), optimizing irradiation dose of X- and gamma-ray

    International Nuclear Information System (INIS)

    Yousefian, M.; Amirinia, C.; Bercsenyi, M.; Horvath, L.


    Mitotic gynogenesis was induced in common carp, Cyprinus carpio L., in hatchery and laboratory conditions, using 60Co gamma-ray and X-ray for inactivation of sperm DNA and a subsequent heat shock for inducing endomitosis. The parameter examined was the dose of irradiation in the range of 70-140 Krad. Carp spermatozoa irradiated by 70-100 Krad doses showed higher motility and fertilization ability than the ones irradiated by 110-140 Krad. Sperm treated with doses of 70-90 Krad showed the same fertility rate, but lower survival rate at embryo stage compared with 100 Krad. The shock temperature and duration applied in these experiments for restoration of diploidy level were 40 degrees C plus/minus 0.1 and 2 min., respectively. The highest frequency of mitotic gynogenetic larvae was achieved by 100 Krad 60Co gamma ray at 34 min. after fertilization, - up to 12.2 percent (at 23 degrees C incubating temperature)

  15. Hybrid incompatibilities are affected by dominance and dosage in the haplodiploid wasp Nasonia (United States)

    Beukeboom, Leo W.; Koevoets, Tosca; Morales, Hernán E.; Ferber, Steven; van de Zande, Louis


    Study of genome incompatibilities in species hybrids is important for understanding the genetic basis of reproductive isolation and speciation. According to Haldane's rule hybridization affects the heterogametic sex more than the homogametic sex. Several theories have been proposed that attribute asymmetry in hybridization effects to either phenotype (sex) or genotype (heterogamety). Here we investigate the genetic basis of hybrid genome incompatibility in the haplodiploid wasp Nasonia using the powerful features of haploid males and sex reversal. We separately investigate the effects of heterozygosity (ploidy level) and sex by generating sex reversed diploid hybrid males and comparing them to genotypically similar haploid hybrid males and diploid hybrid females. Hybrid effects of sterility were more pronounced than of inviability, and were particularly strong in haploid males, but weak to absent in diploid males and females, indicating a strong ploidy level but no sex specific effect. Molecular markers identified a number of genomic regions associated with hybrid inviability in haploid males that disappeared under diploidy in both hybrid males and females. Hybrid inviability was rescued by dominance effects at some genomic regions, but aggravated or alleviated by dosage effects at other regions, consistent with cytonuclear incompatibilities. Dosage effects underlying Bateson–Dobzhansky–Muller (BDM) incompatibilities need more consideration in explaining Haldane's rule in diploid systems. PMID:25926847

  16. Molecular phylogenetics of Echinopsis (Cactaceae): Polyphyly at all levels and convergent evolution of pollination modes and growth forms. (United States)

    Schlumpberger, Boris O; Renner, Susanne S


    In its current circumscription, Echinopsis with 100-150 species is one of the largest and morphologically most diverse genera of Cactaceae. This diversity and an absence of correlated characters have resulted in numerous attempts to subdivide Echinopsis into more homogeneous subgroups. To infer natural species groups in this alliance, we here provide a plastid phylogeny and use it to infer changes in growth form, pollination mode, and ploidy level. We sequenced 3800 nucleotides of chloroplast DNA from 162 plants representing 144 species and subspecies. The sample includes the type species of all genera close to, or included in, Echinopsis as well as a dense sample of other genera of the Trichocereeae and further outgroups. New and published chromosome counts were compiled and traced on the phylogeny, as were pollination modes and growth habits. A maximum likelihood phylogeny confirms that Echinopsis s.l. is not monophyletic nor are any of the previously recognized genera that have more than one species. Pollination mode and, to a lesser extent, growth habit are evolutionarily labile, and diploidy is the rule in Echinopsis s.l., with the few polyploids clustered in just a few clades. The use of evolutionary labile floral traits and growth habit has led to nonnatural classifications. Taxonomic realignments are required, but further study of less evolutionary labile traits suitable for circumscribing genera are needed. Surprisingly, polyploidy seems infrequent in the Echinopsis alliance and hybridization may thus be of minor relevance in the evolution of this clade.

  17. Nicotine supplementation blocks oocyte maturation in Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    Meitria Syahadatina Noor


    Full Text Available Background Indonesia has the third largest tobacco consumption in the world after China and India. Nicotine as the main component of cigarette smoke has negative effects on the reproductive system, such as oocyte maturation, ovulation, and fertilization, and increasing the diploidy of oocytes. The goal of this research was to evaluate the effect of nicotine on oocyte maturation in Rattus norvegicus. Methods This was an experimental study with post test only control group design. The subjects were 40 rats selected homogenously and randomly. They were divided into a control group (receiving carboxy-methyl-cellulose sodium and 3 treatment groups (I-III receiving nicotine subcutaneously for 7 days at dosages of 21 mg/kgBW, 41 kg/kgBW and 84/kgBW, respectively. The observations comprised oocyte maturation stage, viz. germinal vesicle (GV, germinal vesicle breakdown (GVBD, metaphase I and metaphase II. Data were analyzed by one-way Anova with á=0.05, followed by Tukey’s HSD test. Results One-way Anova showed significant differences in oocyte maturation in all groups. Tukey’s HSD test showed that for GV, the differing groups were control and I, control and II, I and III. For GVBD, the differing groups were control and I, I and II, I and III. For metaphase I, the differing groups were control with I, II, and III, I and II, I and III. For metaphase II, the differing groups were control versus I, II, and III, I and II, I and III. Conclusion Low dose of nicotine is capable of affecting oocyte maturation in Rattus norvegicus.

  18. Intraspecific ecological niche divergence and reproductive shifts foster cytotype displacement and provide ecological opportunity to polyploids. (United States)

    Karunarathne, Piyal; Schedler, Mara; Martínez, Eric J; Honfi, Ana I; Novichkova, Anastasiia; Hojsgaard, Diego


    Niche divergence between polyploids and their lower ploidy progenitors is one of the primary mechanisms fostering polyploid establishment and adaptive divergence. However, within-species chromosomal and reproductive variability have usually been neglected in community ecology and biodiversity analyses even though they have been recognized to play a role in the adaptive diversification of lineages. We used Paspalum intermedium, a grass species with diverging genetic systems (diploidy vs. autopolyploidy, allogamy vs. autogamy and sexuality vs. apomixis), to recognize the causality of biogeographic patterns, adaptation and ecological flexibility of cytotypes. Chromosome counts and flow cytometry were used to characterize within-species genetic systems diversity. Environmental niche modelling was used to evaluate intraspecific ecological attributes associated with environmental and climatic factors and to assess correlations among ploidy, reproductive modes and ecological conditions ruling species' population dynamics, range expansion, adaptation and evolutionary history. Two dominant cytotypes non-randomly distributed along local and regional geographical scales displayed niche differentiation, a directional shift in niche optima and signs of disruptive selection on ploidy-related ecological aptitudes for the exploitation of environmental resources. Ecologically specialized allogamous sexual diploids were found in northern areas associated with higher temperature, humidity and productivity, while generalist autogamous apomictic tetraploids occurred in southern areas, occupying colder and less productive environments. Four localities with a documented shift in ploidy and four mixed populations in a zone of ecological transition revealed an uneven replacement between cytotypes. Polyploidy and contrasting reproductive traits between cytotypes have promoted shifts in niche optima, and increased ecological tolerance and niche divergence. Ecologically specialized diploids

  19. Evaluation of multiple bio-pathological factors in colorectal adenocarcinomas: independent prognostic role of p53 and bcl-2. (United States)

    Buglioni, S; D'Agnano, I; Cosimelli, M; Vasselli, S; D'Angelo, C; Tedesco, M; Zupi, G; Mottolese, M


    About 40% of patients with colorectal carcinoma will develop local or distant tumour recurrences. Integrated analyses of bio-pathological markers, predictive of tumour aggressiveness, may offer a more rational approach to planning adjuvant therapy. To this end, we analysed the correlation between p53 accumulation, Bcl-2 expression, DNA ploidy, cell proliferation and conventional clinico-pathological parameters by testing the prognostic significance of these variables in a series of 171 colorectal carcinoma patients with long-term follow-up. The relationships among the various bio-pathological parameters, analysed by multiple correspondence analysis, showed 2 different clinico-biological profiles. The first, characterised by p53 negativity, Bcl-2 positivity, diploidy, low percentage of cells in S-phase (%S-phase), a low Ki-67 score, is associated with Dukes' A-B stage, well differentiated tumours and lack of relapse. The second, defined by p53 positivity, Bcl-2 negativity, aneuploidy, high %S-phase and elevated Ki-67 score, correlates with Dukes' C-D stage, poorly differentiated tumours and presence of relapse. When these parameters were examined according to Kaplan-Meier's method, significantly shorter disease-free (DFS) and overall survival (OS) were also observed in patients bearing p53 positive and Bcl-2 negative tumours, in Dukes' B stage. In multivariate analysis, p53 accumulation and Bcl-2 expression emerged as independent predictors of a worse and better clinical outcome, respectively. Our results indicate that, in colorectal adenocarcinomas, a biological profile, based on the combined evaluation of p53 and Bcl-2, may be useful for identifying high risk patients to be enrolled in an adjuvant setting, mainly in an early stage of the disease. Int. J. Cancer (Pred. Oncol.) 84:545-552, 1999. Copyright 1999 Wiley-Liss, Inc.

  20. The role of multiploidy as unfavorable prognostic variable in colorectal cancer. (United States)

    Cosimelli, M; D'Agnano, I; Tedesco, M; D'Angelo, C; Botti, C; Giannarelli, D; Vasselli, S; Cavaliere, F; Zupi, G; Cavaliere, R


    To analyze the prognostic value of DNA multiploidy in a prospective study on frozen surgical tissue samples from primary colorectal cancer. Survival data from eleven prospective studies collectively comprising about thirteen hundred patients showed that aneuploidy correlated with a 5-year disease-free survival (DFS) significantly poorer than diploidy, and showed the limited prognostic value of results from retrospective studies employing paraffin-embedded material. Multiple tumor samples of fresh/frozen surgical tissues from 120 colorectal cancer patients who had undergone radical surgery were taken for flow cytometric analysis of DNA content, and proliferative activity, shown as percentage of cells in S-phase (%S). The minimum follow-up of this series was 30 months. Univariate and multivariate analyses determined the independent significance of both clinical and biological variable on DFS. Values of %S equal to or higher than 17.3 correlated with a 5-year DFS poorer than values lower than 17.3 (44.5% vs 85.2% respectively; p = .03), even if only in patients younger than 64. The subgroup with multiploid tumors showed a significantly poorer 5-year DFS (44.5% vs. 62.6% in the non multiploid patients; p = .02). Subgrouping the Dukes'B stage alone by multiploidy, the difference in DFS was much more evident (31.2% vs. 68% respectively; p = .0004) and multivariate analysis showed multiploidy as the only significant variable. Above all, adjuvant therapy did not absolutely modify the unfavorable outcome of the multiploid Dukes'B patients. The prospective evaluation of ploidy allowed us to identify a very high-risk subgroup of patients with multiploid tumors. This biological characterization was easy to demonstrate and, above all in node-negative patients, reliable and very effective in terms of prognosis. The presence of multiploidy should result in a more aggressive therapeutic approach in the adjuvant setting.

  1. XTHs from Fragaria vesca: genomic structure and transcriptomic analysis in ripening fruit and other tissues. (United States)

    Opazo, María Cecilia; Lizana, Rodrigo; Stappung, Yazmina; Davis, Thomas M; Herrera, Raúl; Moya-León, María Alejandra


    Fragaria vesca or 'woodland strawberry' has emerged as an attractive model for the study of ripening of non-climacteric fruit. It has several advantages, such as its small genome and its diploidy. The recent availability of the complete sequence of its genome opens the possibility for further analysis and its use as a reference species. Fruit softening is a physiological event and involves many biochemical changes that take place at the final stages of fruit development; among them, the remodeling of cell walls by the action of a set of enzymes. Xyloglucan endotransglycosylase/hydrolase (XTH) is a cell wall-associated enzyme, which is encoded by a multigene family. Its action modifies the structure of xyloglucans, a diverse group of polysaccharides that crosslink with cellulose microfibrills, affecting therefore the functional structure of the cell wall. The aim of this work is to identify the XTH-encoding genes present in F. vesca and to determine its transcription level in ripening fruit. The search resulted in identification of 26 XTH-encoding genes named as FvXTHs. Genetic structure and phylogenetic analyses were performed allowing the classification of FvXTH genes into three phylogenetic groups: 17 in group I/II, 2 in group IIIA and 4 in group IIIB. Two sequences were included into the ancestral group. Through a comparative analysis, characteristic structural protein domains were found in FvXTH protein sequences. In complement, expression analyses of FvXTHs by qPCR were performed in fruit at different developmental and ripening stages, as well as, in other tissues. The results showed a diverse expression pattern of FvXTHs in several tissues, although most of them are highly expressed in roots. Their expression patterns are not related to their respective phylogenetic groups. In addition, most FvXTHs are expressed in ripe fruit, and interestingly, some of them (FvXTH 18 and 20, belonging to phylogenic group I/II, and FvXTH 25 and 26 to group IIIB) display an

  2. SISH/CISH or qPCR as alternative techniques to FISH for determination of HER2 amplification status on breast tumors core needle biopsies: a multicenter experience based on 840 cases. (United States)

    Jacquemier, Jocelyne; Spyratos, Frédérique; Esterni, Benjamin; Mozziconacci, Marie-Joëlle; Antoine, Martine; Arnould, Laurent; Lizard, Sarab; Bertheau, Philippe; Lehmann-Che, Jacqueline; Fournier, Cécile Blanc; Krieger, Sophie; Bibeau, Frédéric; Lamy, Pierre-Jean; Chenard, Marie Pierre; Legrain, Michèle; Guinebretière, Jean-Marc; Loussouarn, Delphine; Macgrogan, Gaëtan; Hostein, Isabelle; Mathieu, Marie Christine; Lacroix, Ludovic; Valent, Alexander; Robin, Yves Marie; Revillion, Françoise; Triki, Magali Lacroix; Seaume, Aline; Salomon, Anne Vincent; de Cremoux, Patricia; Portefaix, Geneviève; Xerri, Luc; Vacher, Sophie; Bièche, Ivan; Penault-Llorca, Frédérique


    Until now, FISH has been the gold standard technique to identify HER2 amplification status in ambiguous cases of breast cancer. Alternative techniques have been developed to increase the capacities of investigating HER2 amplification status. The aims of this multicenter study in a large series of breast cancer patients were to prospectively compare the level of performance of CISH, SISH, and qPCR alternative techniques on paraffin-embedded core biopsies with "gold standard FISH" for evaluation of HER2 amplification status. This study was performed on 840 cases scored by immunohistochemistry (IHC): 0=317 (38%), 1+=183 (22%), 2+=109 (13%), 3+=231 (27%). Each of the 15 French centers participating in the study analyzed 56 breast carcinoma cases diagnosed on fixed paraffin-embedded core biopsies. HER2 amplification status was determined by commercially available FISH used as the reference technique with determination of the HER2/CEN17 ratio or HER2 copy number status. The alternative techniques performed on the same cases were commercially available SISH or CISH and a common qPCR method especially designed for the study including a set of 10 primer pairs: 2 for HER2 (exons 8 and 26), 5 to evaluate chromosome 17 polysomy TAOK1, UTP6, MRM1, MKS1, SSTR2 and 3 for diploidy control TSN, LAP3 and ADAMTS16. The concordance between IHC and FISH was 96% to 95% based on the HER2/CEN17 ratio (n=766) or HER2 copy number (n=840), respectively. The concordance of the alternative techniques with FISH was excellent: 97% and 98% for SISH (498 and 587 cases), 98% and 75% for CISH (108 and 204 cases) and 95% and 93% (699 and 773 cases) for qPCR based on the HER2/CEN17 ratio or HER2 copy number, respectively. Similarly, sensitivity ranged from 99% to 95% for SISH, 100% to 99% for CISH and 89% to 80% for qPCR. The concordance with FISH (ratio) in the 2+ cases was 89% for SISH, 100% for CISH and 93% for qPCR. These alternative techniques showed an excellent concordance with FISH in core

  3. Ploidy plasticity: a rapid and reversible strategy for adaptation to stress. (United States)

    Berman, Judith


    Organisms must be able to grow in a broad range of conditions found in their normal growth environment and for a species to survive, at least some cells in a population must adapt rapidly to extreme stress conditions that kill the majority of cells.Candida albicans, the most prevalent fungal pathogen of humans resides as a commensal in a broad range of niches within the human host. Growth conditions in these niches are highly variable and stresses such exposure to antifungal drugs can inhibit population growth abruptly. One of the mechanisms C. albicans uses to adapt rapidly to severe stresses is aneuploidy-a change in the total number of chromosomes such that one or more chromosomes are present in excess or are missing. Aneuploidy is quite common in wild isolates of fungi and other eukaryotic microbes. Aneuploidy can be achieved by chromosome nondisjunction during a simple mitosis, and in stress conditions it begins to appear after two mitotic divisions via a tetraploid intermediate. Aneuploidy usually resolves to euploidy (a balanced number of chromosomes), but not necessarily to diploidy. Aneuploidy of a specific chromosome can confer new phenotypes by virtue of the copy number of specific genes on that chromosome relative to the copies of other genes. Thus, it is not aneuploidy per se, but the relative copy number of specific genes that confers many tested aneuploidy-associated phenotypes. Aneuploidy almost always carries a fitness cost, as cells express most proteins encoded by genes on the aneuploid chromosome in proportion to the number of DNA copies of the gene. This is thought to be due to imbalances in the stoichiometry of different components of large complexes. Despite this, fitness is a relative function-and if stress is severe and population growth has slowed considerably, then even small growth advantages of some aneuploidies can provide a selective advantage. Thus, aneuploidy appears to provide a transient solution to severe and sudden stress

  4. Complete mole in a dichorionic twin pregnancy after intracytoplasmic sperm injection Mola hidatiforme completa em gravidez bicoriônica após injecção intracitoplasmática de espermatozoides

    Directory of Open Access Journals (Sweden)

    Tiago José Santos de Matos Ferraz


    Full Text Available A dichorionic twin pregnancy with complete hydatidiform mole and coexistent fetus is a rare and challenging situation, whose pathogenesis has not been yet fully understood. We present a case of a 39-year-old woman who underwent intracytoplasmic sperm injection with two embryos transfer. The 12-week gestation ultrasound examination revealed normal fetus and placenta with features of hydatidiform mole, leading to pregnancy termination. Autopsy and histological examinations diagnosed a complete mole coexisting with a normal fetus, and the genetic analysis showed a diploid fetus with biparental genome and molar tissue with paternal diploidy. This case highlighted that complete molar pregnancies may still occur even though pregnancy is achieved after intracytoplasmic sperm injection. A review of the literature was performed by collecting data from the few similar reported cases and by commenting on the pathogenesis of this rare condition.Uma gravidez bicoriônica com mola hidatiforme completa e feto normal é uma situação rara e desafiadora, cuja patogênese não foi ainda totalmente compreendida. Apresenta-se o caso de uma mulher de 39 anos submetida à injeção intracitoplasmática de espermatozoides com transferência de dois embriões. Na ecografia pré-natal realizada na 12ª semana de gestação, foi identificado um embrião morfologicamente normal e uma placenta com características molares. Esta situação resultou na terminação eletiva da gravidez. A autópsia e o estudo histológico permitiram o diagnóstico definitivo de uma mola hidatiforme completa coexistindo com feto normal. A análise genética mostrou feto diploide com genoma biparental e tecido molar com diploidia paterna. Este caso ressaltou que as gestações com mola hidatiforme completa poderão ainda ocorrer, mesmo que a gravidez seja realizada após uma injeção intracitoplasmática de espermatozoides. Foram realizadas uma revisão dos raros casos descritos na literatura

  5. Karyotype in Pediatric Acute Lymphoblastic Leukemia: Impact On Clinical Presentation and Duration of First Remission

    International Nuclear Information System (INIS)

    Khairy, A.M.D.; EL-SISSY, M.D.


    In this study we are aiming at investigating the correlation between karyotype and the clinico pathologic features of pediatric acute lymphoblastic leukemia, duration of first remission and outcome of patients. Material and Methods: A total of 40 pediatric patients with the diagnosis of acute ]lymphoblastic leukemia (ALL) were included in this study. The patients were treated according to ALL P.NCI III/98 protocol used at the Pediatric Oncology Unit, National Cancer Institute, Cairo University. Analyzing the patients with respect to their chromosomal pattern; the majority of patients (17/40, 42.5%) showed a pseudo diploid karyotype. Their mean age was 10.2±4.8 years, M/F ratio 2.4: I. Massive hepatosplenomegaly (HSM) was encountered in 64.7%. The mean total leucocyte count (TLC) was 66.53±5.2 cells per μl. Their mean first complete remission (CR]) was 11.05±2.3 months, EFS was 40% at 12 months and 17.78% at 24 months. Patients with normal karyotype came next, representing ]3/40 (32.5%). Their mean age was 8.4±1.8 years, M/F 0.8: I. Massive HSM was found in 62.5%. The mean TLC was 78.74±3.8 cells per μl. Their mean CR 1 was I I.62±1.2 months, EFS was 41.67% at 12 months and 33.33% at 24 months. The third group represented patients with hyper diploidy (8/40; 20%). Their mean age was 8. 8±3. I years, M/F 7: I. Massive HSM was found in 50%. The mean TLC was 45.16±3.1 cells per μl], their mean CR I was 18.] 0±3.4 months, EFS was 75% at 12 months and 62.5% at 24 months. The least group showed a hypo diploid pattern (5/40; 12.5%). Their mean age was] 3±2.6 years, all were males. Massive HSM was encountered in 100%. The mean TLC was 20.00±2.9 cells per Ill. Their mean CRI was 10±2.8 months. Egyptian patients with childhood ALL who have hyper diploid karyotype, specially those having >50 chromosomes carry a better prognosis than patients with other chromosomal abnormalities. Pseudo diploid karyotype is the most frequent among Egyptian ALL cases and this could

  6. Sperm chromosome analysis and preimplantation genetic diagnosis in an infertile male with mosaic trisomy 18%一例嵌合型18三体少精子症患者精染色体分析及植入前遗传学诊断

    Institute of Scientific and Technical Information of China (English)

    罗玉琴; 钱羽力; 朱瑞建; 叶英辉; 朱宇宁; 金帆


    Objective To analyze the numerical aberration rate of X, Y and chromosome 18 in sperms from an oligozoospermic male with mosaic trisomy 18 and to perform preimplantation genetic diagnosis (PGD) for the couple. Methods G-banding and fluorescence in situ hybridization (FISH) were performed on metaphase chromosome. Sperm was analyzed in three-color FISH with a probe mixture containing CEP18, CEPY and Tel Xq/Yq. A healthy man with normal semen parameters was used as control. Results Significant difference in the rates of disomy for chromosome 18 (0. 63% vs. 0. 16%) and the gonosomes (0. 94% vs. 0. 35%) and diploidy (0. 87% vs. 0. 31%) was found in the spermatozoa between the patient and the control. After four embryos were biopsied in one PGD cycle, two embryos with XY1818 and XX1818 were selected for implanting and clinical pregnancy was ongoing. Conclusion SpermFISH allows further understanding of aneuploidy rate and accurate genetic counseling. FISH-PGD was effective for patient with mosaic trisomy 18.%目的 分析1例嵌合型18三体少精子患者精子18、X、Y染色体数目畸变并进行植入前遗传学诊断(preimplantation genetic djagnosis,PGD).方法 采用G带及荧光原位杂交(fluorescence in situ hybridjzation,FISH)对中期分裂相进行分析,应用三色探针CEP18、CEPY、Tel Xq/Yq对患者精子进行FISH分析,同时以1名染色体正常男性的正常精液作为对照,并对嵌合型18三体患者进行PGD.结果 患者精子18二体率、性染色体二体率和二倍体率分别为0.63%、0.94%和0.87%,与对照组相比(0.16%、0.35%、0.31%)差异有统计学意义.患者进行1个PGD周期的治疗、活检4个胚胎,移植正常的XY1818、XX1818各1胚胎后获得临床妊娠.结论 精子FISH分析可为其提供更准确的遗传咨询及指导植入前遗传学诊断,FISH-PGD可有效地应用于嵌合型18三体的植入前遗传学诊断.

  7. [Informative predation: Towards a new species concept]. (United States)

    Lherminier, Philippe


    lytochal and deuterotochal parthenogenesis of aphids, and the innumerable para- and pseudo-sexual strategies of plants opportunistically combine the two modes of asexual replication and sexual combination. However, for the majority of animals and multicellular plants that produce many gametes, numerical proliferation by descendants and informative diversity by sexuality are mutually implicated, for example in the seed. The true discovery of eukaryotes may not be the "true nucleus", as their name implies, but an orderly informative function. The field of recombinations circumscribes a class of partners genetically compatible with each other, each simultaneously prey and predator of the DNA of the other. The mythical Maxwell demon capable of tracing entropy by sorting molecules according to their state does exist: each mate is the other's Maxwell's demon. While a sexless bacterium is simply divided into two cells, two sexual parents work together to produce a single offspring a time. Added to this are the burdens involved in meiosis and crossing-over, cellular diploidy, and mating. Sex produces an information gain that is paid for by a cost of energy-material, and this barter must be fair to survive. The domains of sexual intercourse are very diverse: uniparental reproduction, alternation of asexual proliferation and sexual information, self-fertilization, endogamy, exogamy, panmixis, diffuse or structured polymorphism, fertile or sterile hybridization, horizontal transfers. Each species is a recombination field between two domains, cloning and hybridization. Multiplicative descent and informative fertilization are organically distinct, but selectively associated: the information produced by the parents' sexuality favors the predation of matter-energy and therefore the proliferation of offspring, and this proliferation in turn favors the sexed producers of information. The equation specific to each species is: enough energy to proliferate, enough information to diversify