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1.
Genet Mol Res ; 15(1)2016 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-26909961

RESUMEN

Jatropha gossypiifolia L. (Euphorbiaceae) is widely used in popular medicine. However, further toxicological studies are necessary for its reliable use. The present study aimed to evaluate the cytotoxic, genotoxic, and mutagenic effects of ethanolic and aqueous leaf extracts of J. gossypiifolia, using the test system Allium cepa. In addition, the phytochemical profile of the extracts was also obtained. Seeds of A. cepa were subjected to different concentrations of the two extracts (0.001, 0.01, 0.1, 1, and 10 mg/mL). Distilled water was used for the negative control and methyl methanesulfonate (4 x 10(-4) M) and trifluralin (0.84 ppm) for the positive controls. The values of mitotic index at all concentrations of ethanolic extract and at 0.1, 1, and 10 mg/mL aqueous extract showed a significant decrease. Alterations, such as chromosome adherence, C-metaphases, chromosome bridges, nuclear buds, and micronuclei were verified in both extracts but chromosome loss indicating genotoxic activity was observed only in the ethanolic extract. Presence of micronuclei on administration of the extracts, also indicated mutagenic action at the chromosome level. In the ethanolic extract, aneugenicity seemed to be the main activity, probably as a result of the action of terpenes and/or flavonoids, whereas in the aqueous extract, clastogenic action appeared to be the principal activity, presumably as a consequence of the effect of flavonoids and/or saponins. Thus, we suggest that the extracts of this species should be used with great caution for medicinal purpose.


Asunto(s)
Aberraciones Cromosómicas/inducido químicamente , Jatropha/efectos adversos , Cebollas/efectos de los fármacos , Extractos Vegetales/efectos adversos , Hojas de la Planta/química , Flavonoides , Jatropha/química , Jatropha/toxicidad , Índice Mitótico , Cebollas/genética , Extractos Vegetales/química , Extractos Vegetales/toxicidad , Saponinas , Semillas/efectos de los fármacos , Semillas/genética
2.
Clin Transl Oncol ; 16(3): 266-72, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23775149

RESUMEN

INTRODUCTION: Although most invasive cervical cancer (ICC) harbor <20 human papillomavirus (HPV) genotypes, use of HPV screening to predict ICC from HPV has low specificity, resulting in multiple and costly follow-up visits and overtreatment. We examined DNA methylation at regulatory regions of imprinted genes in relation to ICC and its precursor lesions to determine if methylation profiles are associated with progression of HPV-positive lesions to ICC. MATERIALS AND METHODS: We enrolled 148 controls, 38 CIN and 48 ICC cases at Kilimanjaro Christian Medical Centre from 2008 to 2009. HPV was genotyped by linear array and HIV-1 serostatus was tested by two rapid HIV tests. DNA methylation was measured by bisulfite pyrosequencing at regions regulating eight imprinted domains. Logistic regression models were used to estimate odd ratios. RESULTS: After adjusting for age, HPV infection, parity, hormonal contraceptive use, and HIV-1 serostatus, a 10 % decrease in methylation levels at an intragenic region of IGF2 was associated with higher risk of ICC (OR 2.00, 95 % CI 1.14-3.44) and cervical intraepithelial neoplasia (CIN) (OR 1.51, 95 % CI 1.00-2.50). Methylation levels at the H19 DMR and PEG1/MEST were also associated with ICC risk (OR 1.51, 95 % CI 0.90-2.53, and OR 1.44, 95 % CI 0.90-2.35, respectively). Restricting analyses to women >30 years further strengthened these associations. CONCLUSIONS: While the small sample size limits inference, these findings show that altered DNA methylation at imprinted domains including IGF2/H19 and PEG1/MEST may mediate the association between HPV and ICC risk.


Asunto(s)
Metilación de ADN , Factor II del Crecimiento Similar a la Insulina/genética , Infecciones por Papillomavirus/complicaciones , Proteínas/genética , Displasia del Cuello del Útero/genética , Neoplasias del Cuello Uterino/genética , Adulto , Femenino , Humanos , Persona de Mediana Edad , Infecciones por Papillomavirus/genética , Neoplasias del Cuello Uterino/virología , Displasia del Cuello del Útero/virología
3.
Cytogenet Genome Res ; 135(2): 111-7, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21893968

RESUMEN

Phosphorylation of serine 10 in histone H3 (H3S10ph) has been extensively analyzed and appears to be a conserved chromatin change associated with chromosome condensation in different eukaryotic organisms. In this work, we report the distribution of H3S10ph during meiosis in monocentric and holokinetic chromosomes of 6 insect species and in mitotic chromosomes of 7 mammalian species, aiming to investigate the labeling patterns in phylogenetically distant groups. The results indicated a very similar phosphorylation timing and distribution pattern among insects. The sex chromosomes of insects analyzed were always undercondensed and hypophosphorylated. Similarly, the micro chromosomes of the bug Pachylis aff pharaonis were also undercondensed and hypophosphorylated. Holokinetic chromosomes of bugs and monocentric chromosomes of grasshoppers and beetles displayed identical phosphorylation pattern in spite of the difference in the centromere type. Among mammals, a uniform chromosome phosphorylation was observed in marsupials, whereas bat chromosomes displayed a longitudinal banding pattern. These data indicate that, in general, the intensity of H3S10 phosphorylation in animal chromosomes is variable among the distinct chromosome types and associated with the degree of chromatin condensation at metaphase, but it may vary between different groups of animals.


Asunto(s)
Cromosomas de Insectos/metabolismo , Cromosomas de los Mamíferos/metabolismo , Histonas/metabolismo , Serina/metabolismo , Animales , Quirópteros , Cromatina/genética , Cromatina/metabolismo , Cromosomas de Insectos/genética , Cromosomas de los Mamíferos/genética , Escarabajos , Saltamontes , Meiosis/genética , Metafase/genética , Mitosis/genética , Zarigüeyas , Fosforilación , Especificidad de la Especie
4.
Micron ; 40(8): 851-9, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19646883

RESUMEN

Conventional chromosome staining has suggested that more than 75% of the tomato chromosomes are constituted by heterochromatin. In order to determine whether more deeply stained proximal regions are classic heterochromatin, the distributions of C-bands and chromomycin A(3) (CMA) bands, and the prophase condensation patterns, were analysed in tomato. In this and most other species of the tomato clade, the 5S and 45S rDNA sites were also localised. In tomato, CMA banding was similar to C-banding. After conventional staining, all species displayed large condensed heteropycnotic regions that did not correspond to C-bands or CMA bands. Analyses of the CMA banded karyotypes revealed a low heterochromatin content. Around 12-17% of the chromatin of tomato was CMA(+) and 1/4 to 1/5 of this heterochromatin corresponded to 45S rDNA. In other species, the CMA(+) heterochromatin showed extensive variation (8-35%), but was never near the values found in the literature for tomato. These data suggest the existence of three principal fractions of chromatin in tomato and related species: the late condensed euchromatin corresponding to the terminal regions of the chromosomes, the precocious condensed euchromatin that occupies the major part of the chromosomes and the constitutive heterochromatin that represents those regions revealed by C-bands.


Asunto(s)
Cromatina/química , Bandeo Cromosómico , Cromosomas/química , Cromosomas/ultraestructura , Solanum lycopersicum/fisiología , ADN Ribosómico/genética , ARN Ribosómico/genética , ARN Ribosómico 5S/genética
5.
Cytogenet Genome Res ; 119(3-4): 275-81, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-18253042

RESUMEN

Mandarin is the common name of a heterogeneous group of Citrus species with a large range of variation in morphological and molecular characters as well as in number of species. Aiming to identify chromosome markers and to clarify the relationship within this group, the karyotype of 13 mandarin accessions were analyzed using CMA/DAPI staining and in situ hybridization with 5S and 45S rDNA probes. The CMA band pattern together with the position of rDNA sites revealed that mandarins can be separated karyologically into three groups: a) C. sunki and C. reshni; b) the Mediterranean mandarin, C. deliciosa, and the closely related C. tangerina cv. Dancy and C. reticulata cv. Cravo; c) the remaining cultivars, which are cytologically heterozygous and most probably interspecific hybrids. The former two groups are assumed to be pure species together with C. medica and C. grandis. A chromosome marker for mandarin species was identified and the relationship among the pure species and some hybrids is discussed.


Asunto(s)
Cromosomas de las Plantas/genética , Citrus/genética , Hibridación Genética , Cromomicina A3/metabolismo , Bandeo Cromosómico , ADN Ribosómico/metabolismo , Marcadores Genéticos , Cariotipificación , Especificidad de la Especie
6.
Genetica ; 129(3): 273-9, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16897447

RESUMEN

Several chromosome types have been recognized in Citrus and related genera by chromomycin A(3 )(CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata ("Barnes", "Fawcett", "Flying Dragon", "Pomeroy", "Rubidoux", "USDA") and one P. trifoliata x C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed a similar CMA(+) banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore, this B chromosome can be used as a marker to recognize the intergeneric Poncirus x Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic cell fusions involving trifoliate orange germplasm.


Asunto(s)
Cromosomas de las Plantas/genética , Citrus/genética , Hibridación Genética , Poncirus/genética , Brasil , Bandeo Cromosómico , Cartilla de ADN , ADN Ribosómico/genética , Marcadores Genéticos/genética , Hibridación Fluorescente in Situ , Especificidad de la Especie
7.
Genetica ; 126(1-2): 33-41, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16502083

RESUMEN

In the present work we report the phosphorylation pattern of histone H3 and the development of microtubular structures using immunostaining techniques, in mitosis of Rhynchospora tenuis (2n = 4), a Cyperaceae with holocentric chromosomes. The main features of the holocentric chromosomes of R. tenuis coincide with those of other species namely: the absence of primary constriction in prometaphase and metaphase, and the parallel separation of sister chromatids at anaphase. Additionaly, we observed a highly conserved chromosome positioning at anaphase and early telophase sister nuclei. Four microtubule arrangements were distinguished during the root tip cell cycle. Interphase cells showed a cortical microtubule arrangement that progressively forms the characteristic pre-prophase band. At prometaphase the microtubules were homogeneously distributed around the nuclear envelope. Metaphase cells displayed the spindle arrangement with kinetochore microtubules attached throughout the entire chromosome extension. At anaphase kinetochoric microtubules become progressively shorter, whereas bundles of interzonal microtubules became increasingly broader and denser. At late telophase the microtubules were observed equatorially extended beyond the sister nuclei and reaching the cell wall. Immunolabelling with an antibody against phosphorylated histone H3 revealed the four chromosomes labelled throughout their entire extension at metaphase and anaphase. Apparently, the holocentric chromosomes of R. tenuis function as an extended centromeric region both in terms of cohesion and H3 phosphorylation.


Asunto(s)
Cromosomas de las Plantas/metabolismo , Cyperaceae/genética , Histonas/metabolismo , Microtúbulos/metabolismo , Mitosis/fisiología , Anafase/fisiología , Cromosomas de las Plantas/fisiología , Cyperaceae/metabolismo , Inmunohistoquímica , Microtúbulos/fisiología , Fosforilación
8.
Plant Cell Rep ; 24(3): 172-8, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15812661

RESUMEN

To evaluate the mitotic stability of Triticum aestivum x Thinopyrum ponticum derivatives (BC(2)F(7) and BC(2)F(5) doubled haploids), chromosome counting by both conventional and immunostaining techniques, and measurement of DNA content were performed. The wheat progenitor line, PF 839197, the wheat recurrent parent CEP 19 and the control Chinese Spring were also investigated. In the hybrid derivatives, chromosome number ranged from 2n=36 to 60, with a predominance of chromosome numbers higher than 2n=42, that was confirmed by determination of nuclear DNA content. Chinese Spring' and PF 839197 were stable, but CEP 19 showed chromosome number variation (20%). Analyses of non-pretreated cells revealed the presence of anaphase bridges, lagging chromatids, chromosome fragments and micronuclei. Immunostaining with an antibody recognizing histone H3 phosphorylated showed dicentric chromatids forming anaphase bridges and pericentromeric phosphorylation at centric chromosome fragments but not at lagging chromatids. The possible causes of the observed mitotic instability are discussed.


Asunto(s)
Inestabilidad Cromosómica , Cromosomas de las Plantas/genética , ADN de Plantas/genética , Histonas/genética , Mitosis/genética , Triticum/genética , Núcleo Celular/genética , Quimera , Cruzamientos Genéticos , Histonas/metabolismo , Cariotipificación , Fosforilación , Plantas Modificadas Genéticamente
9.
Cytogenet Genome Res ; 109(1-3): 276-82, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15753587

RESUMEN

Lemons, limes and citron constitute a group of closely related Citrus species, whose species delimitations and taxonomic relationships are unclear. In order to identify karyotypic similarities and species relationships within this group, the CMA+/DAPI- banding pattern and the distribution of the 5S and 45S rDNA sites of 10 accessions of lime, lemon, and citron were investigated. The four cultivars of C. limon analyzed showed the same pattern of CMA+ bands and rDNA sites, suggesting that they originated from a single germplasm, later differentiated by distinct somatic mutations. The lemons C. jambhiri, C. limonia and C. volkameriana displayed karyotypes very similar to each other, but they differed from C. limon by the absence of a single chromosome with one band in each telomere. The limes, C. aurantifolia and C. limettioides, seemed less related to each other and exhibited different heteromorphic chromosome pairs. In C. aurantifolia, the presence of a chromosome type unknown in all other Citrus species cytologically known so far supports the assumption that this accession may be derived from a hybrid with a species from the subgenus Papeda or from another genus. Citrus medica was the only homozygous accession of this group and all of its chromosome types were clearly represented in limes and lemons, some of them forming heteromorphic pairs. The analysis of the distribution of rDNA sites allowed a further refinement of the comparison among accessions. The lemons and limes were heterozygous for all rDNA sites, whereas C. medica was entirely homozygous. These data support the hypothesis that C. medica is a true species while the other nine accessions are hybrids.


Asunto(s)
Cromosomas de las Plantas/genética , Citrus/clasificación , Citrus/genética , Mapeo Cromosómico , Cromosomas de las Plantas/ultraestructura , ADN de Plantas/genética , ADN Ribosómico/genética , Isoenzimas/genética , Cariotipificación , Mutación , Plantas Medicinales/genética
10.
Biocell ; 19(2): 113-23, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7550572

RESUMEN

1. The electrocytes from the electric organ of the Patagonian ray P. extenta are very unusual cells: semicircular in shape, multinucleated and highly polarized. They have an anterior, concave, innervated face, which exhibits positive histochemical reactions for acetylcholinesterase and for the nicotinic acetylcholine receptor. Multiple nerve-endings are covered with Schwann cell projections, similar to those present in skeletal muscle. Their posterior face is convex, non-innervated and is in contact with collagen fibres. 2. The cytoplasm of these electrocytes possesses abundant filamentous actin (F-actin), orderly distributed in the cell and exhibiting intense fluorescence with NBD-phallacidin. The F-actin is in contact with Z-lines as in muscle, and in contrast with Torpedo (Kordeli et al., 1986, 1987) and Discopyge (Vidal et al., 1986, 1989a) electrocytes, where it is confined to the non-innervated face. 3. Electrocytes of this Rajidae are an ideal model for the study of F-actin because of the similar embryological origin with skeletal muscle tissue and also because of the peculiar characteristics of their cytoplasm, packed full with F-actin. In addition, electric organs could constitute an alternative biological source for the study of the cholinergic synapse.


Asunto(s)
Acetilcolinesterasa/metabolismo , Actinas/metabolismo , Órgano Eléctrico/ultraestructura , Receptores Nicotínicos/metabolismo , Rajidae/anatomía & histología , Animales , Citoesqueleto/ultraestructura , Femenino , Microscopía Electrónica
11.
Biocell ; Biocell;19(2): 113-23, 1995 Aug.
Artículo en Inglés | BINACIS | ID: bin-37241

RESUMEN

1. The electrocytes from the electric organ of the Patagonian ray P. extenta are very unusual cells: semicircular in shape, multinucleated and highly polarized. They have an anterior, concave, innervated face, which exhibits positive histochemical reactions for acetylcholinesterase and for the nicotinic acetylcholine receptor. Multiple nerve-endings are covered with Schwann cell projections, similar to those present in skeletal muscle. Their posterior face is convex, non-innervated and is in contact with collagen fibres. 2. The cytoplasm of these electrocytes possesses abundant filamentous actin (F-actin), orderly distributed in the cell and exhibiting intense fluorescence with NBD-phallacidin. The F-actin is in contact with Z-lines as in muscle, and in contrast with Torpedo (Kordeli et al., 1986, 1987) and Discopyge (Vidal et al., 1986, 1989a) electrocytes, where it is confined to the non-innervated face. 3. Electrocytes of this Rajidae are an ideal model for the study of F-actin because of the similar embryological origin with skeletal muscle tissue and also because of the peculiar characteristics of their cytoplasm, packed full with F-actin. In addition, electric organs could constitute an alternative biological source for the study of the cholinergic synapse.

12.
Neurochem Res ; 18(5): 599-603, 1993 May.
Artículo en Inglés | MEDLINE | ID: mdl-8474578

RESUMEN

The ganglioside composition of membranes enriched in nicotinic acetylcholine receptor (AChR) from the electric rays Discopyge tschudii and Torpedo marmorata has been determined, and compared to that of total electric organ. A ganglioside having the chromatographic mobility of GM2 constitutes the major ganglioside (approximately 60%) in total D. tschudii electric organ, followed by a component with the mobility of GD3 (approximately 10%), and a component running just below GD1a (about 12%). Minor constituents running as GM3 (2%) and as polysialogangliosides (comprising 8-15%) were also observed. Purified native membranes of D. tschudii and T. marmorata displayed a similar profile, except that they were richer in a GM1-like component, and the proportion of GM2-like gangliosides was lower than that in total electric organ. Using a 125I-cholera toxin overlay assay on neuraminidase-treated high-performance thin layer chromatograms, the presence of GM1, GD1a and trace amounts of GD1b and GT1 (or GQ) were detected in D. Tschudii total membranes. Immunocytochemical trechniques showed the co-localization of gangliosides GQ1c/GT1c/GP1c, recognized by the monoclonal antibody Q211, and the AChR at the ventral, innervated face of the electrocyte.


Asunto(s)
Órgano Eléctrico/metabolismo , Gangliósidos/metabolismo , Receptores Colinérgicos/metabolismo , Torpedo/metabolismo , Animales , Membrana Celular/metabolismo , Gangliósido G(M1)/metabolismo , Gangliósido G(M2)/metabolismo , Inmunohistoquímica
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