Intrachromosomal distribution of telomeric repeats in Eumops glaucinus and eumops perotis (Molossidae, Chiroptera)

The location of chromosomal telomeric repeats (TTAGGG)(n) was investigated in two species of the Molossidae family, Eumops glaucinus and Eumops perotis. The diploid chromosome number (2n) is 40 in E. glaucinus and 48 in E. perotis and the fundamental numbers (FN) are 64 and 58, respectively. It has been suggested that the E. glaucinus karyotype has evolved from the E. perotis karyotype through Robertsonian fusion events. In the present study, the telomeric sequences were detected at the termini of chromosomes in both species. In addition, E. glaucinus also displayed telomeric repeats in centromeric and pericentromeric regions in almost all biarmed chromosomes. Conversely, in E. perotis pericentromeric signals were only observed in two biarmed chromosomes. In both E. glaucinus and E. perotis, such telomeric sequences were observed as part of the heterochromatin. The interstitial sites of telomeric sequences suggest that they are remnants of telomeres of ancestral chromosomes that participated in the fusion event.

Color evaporation induced rapidity gaps

We show that soft color rearrangement of final states can account for the appearance of rapidity gaps between jets. In the color evaporation model the probability to form a gap is simply determined by the color multiplicity of the final state. This model has no free parameters and reproduces all data obtained by the ZEUS, H1, DØ, and CDF collaborations. © 2001 Elsevier Science B.V. All rights reserved.

Estudo das alterações cariotípicas, do rearranjo gênico BCR/ABL e do cromossomo 20 em leucemias

Leukemia is a genetic disease from a noncontrolled abnormal process of the hematopoietic cells' differentiation and proliferation. Some alterations of structure and number of chromosomes have been well and specifically observed in leukemia. The detection of these alterations is highly significant in providing the patients' diagnosis, prognosis and treatment as well as the understanding of the genetic bases of this disease. The purpose of this work is to study some chromosomal alterations in peripheral blood and/or bone marrow in patients with different leukemia types by means of conventional cytogenetic techniques, and also to investigate the presence of BCR/ABL gene rearrangement and some alterations in chromosome 20 by the FISH technique. Samples of peripheral blood and/or bone marrow of 28 patients, who were not under chemoor radio-therapeutic treatment, were studied: 15 with CML, 11 with AML and 2 with ALL. The alteration most frequent was t(9;22) in the CML, whose presence or absence was related to a good or bad prognosis, respectively. A case of AMI showed inv(16)(p13q22), related to a good prognosis. Some alterations not reported previously in the literature were found, such as the trisomy in chromosome 2 associated to chromosome Ph showing some disease progress in one of the CML cases and t(5;16)(q13;q22) in an AML patient. One of the cases was submitted to an allogeneic hone marrow transplant. The monitoring after the 23 rd day of transplant, detected 95% of the donor cells suggesting the procedure had succeeded. Two patients, an AMI and the other ALL, showed trisomy of chromosome 20 in the neoplastic cells. The results showed the importance of the cytogenetic analysis in relation to leukemia, its direct benefits to the patients and the biological mechanisms involved in this disease. They also allowed the introduction in the Genetic Service of FAMERP techniques to obtain the bone marrow metaphases and the FISH technique.

Morphology changes induced by laser irradiation on disperse red 13 films prepared by physical vapor deposition

Surface morphology changes induced by argon laser irradiation (514 nm) on disperse red 13 (DR13) films prepared by physical vapor deposition (PVD) were investigated. Atomic force microscopy was used to characterize the irradiated sample for different periods of irradiation. Needle-shape structures are observed which are attributed to the symmetry of DR13 molecules. The film becomes increasingly closely packed with the irradiation, with lower root mean square roughness for long exposure times. This is due to photoisomerization of DR13 molecules and probably heating of the sample, which can provide the required mobility for the molecular rearrangement. The rearrangement is such that voids in the film are filled in upon irradiating the sample, thus decreasing the film roughness and increasing the packing.

Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam

Background: Despite the extensive polymorphism at the merozoite surface protein-1 (MSP-1) locus of Plasmodium falciparum, that encodes a major repetitive malaria vaccine candidate antigen, identical and nearly identical alleles frequently occur in sympatric parasites. Here we used microsatellite haplotyping to estimate the genetic distance between isolates carrying identical and nearly identical MSP-1 alleles. Methods: We analyzed 28 isolates from hypoendemic areas in north-western Brazil, collected between 1985 and 1998, and 23 isolates obtained in mesoendemic southern Vietnam in 1996. MSP-1 alleles were characterized by combining PCR typing with allele-specific primers and partial DNA sequencing. The following single-copy microsatellite markers were typed: Polyα, TA42 (only for Brazilian samples), TA81, TA1, TA87, TA109 (only for Brazilian samples), 2490, ARAII, PfG377, PfPK2, and TA60. Results: The low pair-wise average genetic distance between microsatellite haplotypes of isolates sharing identical MSP-1 alleles indicates that epidemic propagation of discrete parasite clones originated most identical MSP-1 alleles in parasite populations from Brazil and Vietnam. At least one epidemic clone propagating in Brazil remained relatively unchanged over more than one decade. Moreover, we found no evidence that rearrangements of MSP-1 repeats, putatively created by mitotic recombination events, generated new alleles within clonal lineages of parasites in either country. Conclusion: Identical MSP-1 alleles originated from co-ancestry in both populations, whereas nearly identical MSP-1 alleles have probably appeared independently in unrelated parasite lineages.

Clinical outcome in chronic myeloid leukemia after allogeneic hematopoietic stem cell transplantation: The experience of the Bone Marrow Transplantation Unit of FUNFARME/BRAZIL using FISH

Investigation of the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in chronic myeloid leukemia patients is essential to predict prognosis and survival. In 20 patients treated at the Bone Marrow Transplantation Unit of São José do Rio Preto (São Paulo, Brazil), we used fluorescence in situ hybridization (FISH) to investigate the frequency of cells with BCR/ABL rearrangement at diagnosis and at distinct intervals after allo-HSCT until complete cytogenetic remission (CCR). We investigated the disease-free survival, overall survival in 3 years and transplant-related mortality rates, too. Bone marrow samples were collected at 1, 2, 3, 4, 6, 12, and 24 months after transplantation and additional intervals as necessary. Success rate of the FISH analyses was 100%. CCR was achieved in 75% of the patients, within on average of 3.9 months; 45% patients showed CCR within 60 days after HSCT. After 3 years of the allo-HSCT, overall survival rate was 60%, disease-free survival was 50% and the transplant-related mortality rate was 40%. The study demonstrated that the BCR-ABL FISH assay is useful for follow-up of chronic myeloid leukemia patients after HSCT and that the clinical outcome parameters in our patient cohort were similar to those described for other bone marrow transplantation units. ©FUNPEC-RP.

Suicide nucleophilic attack: Reactions of benzohydroxamate anion with bis(2,4-dinitrophenyl) phosphate

(Chemical Equation Presented) The reaction between the benzohydroxamate anion (BHO-) and bis(2,4-dinitrophenyl)phosphate (BDNPP) has been examined kinetically, and the products were characterized by mass and NMR spectroscopy. The nucleophilic attack of BHO- follows two reaction paths: (i) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement to phenyl isocyanate, aniline, diphenylurea, and O-phenylcarbamyl benzohydroxamate; and (ii) on the aromatic carbon, giving an intermediate that was detected but slowly decomposes to aniline and 2,4-dinitrophenol. Thus, the benzohydroxamate anion can be considered a self-destructive molecular scissor since it reacts and loses its nucleophilic ability. © 2009 American Chemical Society.

The mechanism of dephosphorylation of bis(2,4-dinitrophenyl) phosphate in mixed micelles of cationic surfactants and lauryl hydroxamic acid

(Figure Presented) Mixed micelles of cetyltrimethylammonium bromide (CTABr) or dodecyltrimethylammonium bromide (DTABr) and the α-nucleophile, lauryl hydroxamic acid (LHA) accelerate dephosphorylation of bis(2,4-dinitrophenyl) phosphate (BDNPP) over the pH range 4-10. With a 0.1 mole fraction of LHA in DTABr or CTABr, dephosphorylation of BDNPP is approximately 10 4-fold faster than its spontaneous hydrolysis, and monoanionic LHA - is the reactive species. The results are consistent with a mechanism involving concurrent nucleophilic attack by hydroxamate ion (i) on the aromatic carbon, giving an intermediate that decomposes to undecylamine and 2,4-dinitrophenol, and (ii) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement yielding a series of derivatives including N,N-dialkylurea, undecylamine, undecyl isocyanate, and carbamyl hydroxamate. © 2009 American Chemical Society.

Chromosomal evolution of neotropical cichlids: The role of repetitive DNA sequences in the organization and structure of karyotype

Cichlids are important in the aquaculture and ornamental fish trade and are considered models for evolutionary biology. However, most studies of cichlids have investigated African species, and the South American cichlids remain poorly characterized. Studies in neotropical regions have focused almost exclusively on classical cytogenetic approaches without investigating physical chromosomal mapping of specific sequences. The aim of the present study is to investigate the genomic organization of species belonging to different tribes of the subfamily Cichlinae (Cichla monoculus, Astronotus ocellatus, Geophagus proximus, Acaronia nassa, Bujurquina peregrinabunda, Hoplarchus psittacus, Hypselecara coryphaenoides, Hypselecara temporalis, Caquetaia spectabilis, Uaru amphiacanthoides, Pterophyllum leopoldi, Pterophyllum scalare, and Symphysodon discus) and reexamine the karyotypic evolutionary patterns proposed for this group. Variations in some cytogenetic markers were observed, although no trends were found in terms of the increase, decrease, or maintenance of the basal diploid chromosome number 2n = 48 in the tribes. Several species were observed to have 18S rDNA genetic duplications, as well as multiple rDNA loci. In most of the taxa analyzed, the 5S rDNA was located in the interstitial region of a pair of homologous chromosomes, although variations from this pattern were observed. Interstitial telomere sites were also observed and appear to be involved in chromosomal rearrangement events and the accumulation of repeat-rich satellite DNA sequences. Our data demonstrated the karyotypic diversity that exists among neotropical cichlids, suggesting that most of this diversity is due to the repetitive sequences present in heterochromatic regions and that repeat sequences have greatly influenced the karyotypic evolution of these fishes. © 2012 Springer Science+Business Media B.V.

High chromosome variability and the presence of multivalent associations in buthid scorpions

In this study, we investigated the mitotic and meiotic chromosomes of 11 Buthidae scorpion species, belonging to three genera (Ananteris, Rhopalurus and Tityus), to obtain detailed knowledge regarding the mechanisms underlying the intraspecific and/or interspecific diversity of chromosome number and the origin of the complex chromosome associations observed during meiosis. The chromosomes of all species did not exhibit a localised centromere region and presented synaptic and achiasmatic behaviour during meiosis I. Spermatogonial and/or oogonial metaphase cells of these buthids showed diploid numbers range from 2n = 6 to 2n = 28. In most species, multivalent chromosome associations were observed in pachytene and postpachytene nuclei. Moreover, intraspecific variability associated with the presence or absence of chromosome chains and the number of chromosomes in the complex meiotic configurations was observed in some species of these three genera. Silver-impregnated cells revealed that the number and location of nucleolar organiser regions (NORs) remained unchanged despite extensive chromosome variation; notably, two NORs located on the terminal or subterminal chromosome regions were commonly observed for all species. C-banded and fluorochrome-stained cells showed that species with conspicuous blocks of heterochromatin exhibited the lowest rate of chromosomal rearrangement. Based on the investigation of mitotic and meiotic cells, we determined that the intraspecific variability occurred as a consequence of fission/fusion-type chromosomal rearrangements in Ananteris and Tityus species and reciprocal translocation in Rhopalurus species. Furthermore, we verified that individuals presenting the same diploid number differ in structural chromosome organisation, giving rise to intraspecific differences of chromosome association in meiotic cells (bivalent-like elements or chromosome chains). © 2013 Springer Science+Business Media Dordrecht.

Ideas of four-fermion operators in hadron physics

Four-fermion operators have been utilized in the past to link the quarkexchange processes in the interaction of hadrons with the effective mesonexchange amplitudes. In this paper, we apply the similar idea of Fierz rearrangement to the electromagnetic processes and focus on the electromagnetic form factors of nucleon and electron. We explain the motivation of using four-fermion operators and discuss the advantage of this method in computing electromagnetic processes.

Ideas of four-fermion operators in electromagnetic form factor calculations

Four-fermion operators have been used in the past to link the quark-exchange processes in the interaction of hadrons with the effective meson-exchange amplitudes. In this paper, we apply the similar idea of a Fierz rearrangement to the self-energy and electromagnetic processes and focus on the electromagnetic form factors of the nucleon and the electron. We explain the motivation of using four-fermion operators and discuss the advantage of this method in computing electromagnetic processes. © 2013 American Physical Society.

Interclonal Variations in the Molecular Karyotype of Trypanosoma cruzi: Chromosome Rearrangements in a Single Cell-Derived Clone of the G Strain

Trypanosoma cruzi comprises a pool of populations which are genetically diverse in terms of DNA content, growth and infectivity. Inter- and intra-strain karyotype heterogeneities have been reported, suggesting that chromosomal rearrangements occurred during the evolution of this parasite. Clone D11 is a single-cell-derived clone of the T. cruzi G strain selected by the minimal dilution method and by infecting Vero cells with metacyclic trypomastigotes. Here we report that the karyotype of clone D11 differs from that of the G strain in both number and size of chromosomal bands. Large chromosomal rearrangement was observed in the chromosomes carrying the tubulin loci. However, most of the chromosome length polymorphisms were of small amplitude, and the absence of one band in clone D11 in relation to its reference position in the G strain could be correlated to the presence of a novel band migrating above or below this position. Despite the presence of chromosomal polymorphism, large syntenic groups were conserved between the isolates. The appearance of new chromosomal bands in clone D11 could be explained by chromosome fusion followed by a chromosome break or interchromosomal exchange of large DNA segments. Our results also suggest that telomeric regions are involved in this process. The variant represented by clone D11 could have been induced by the stress of the cloning procedure or could, as has been suggested for Leishmania infantum, have emerged from a multiclonal, mosaic parasite population submitted to frequent DNA amplification/deletion events, leading to a 'mosaic' structure with different individuals having differently sized versions of the same chromosomes. If this is the case, the variant represented by clone D11 would be better adapted to survive the stress induced by cloning, which includes intracellular development in the mammalian cell. Karyotype polymorphism could be part of the T. cruzi arsenal for responding to environmental pressure. © 2013 Lima et al.

Early endosome antigen 1 (EEA1) decreases in macrophages infected with Paracoccidioides brasiliensis

Paracoccidioidomycosis (PCM) is a chronic granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis, endemic in Latin America. P. brasiliensis has been observed in epithelial cells in vivo and in vitro, as well as within the macrophages. The identification of the mechanism by which it survives within the host cell is fertile ground for the discovery of its pathogenesis since this organism has the ability to induce its own endocytosis in epithelial cells and most likely in macrophages. The study of the expression of endocytic proteins pathway and co-localization of microorganisms enable detection of the mechanism by which microorganisms survive within the host cell. The aim of this study was to evaluate the expression of the endocytic protein EEA1 (early endosome antigen 1) in macrophages infected with P. brasiliensis. For detection of EEA1, three different techniques were employed: immunofluorescence, real-time polymerase chain reaction (PCR) and immunoblotting. In the present study, decreased expression of EEA1 as well as the rearrangement of the actin was observed when the fungus was internalized, confirming that the input mechanism of the fungus in macrophages occurs through phagocytosis. © 2013 ISHAM.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)