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1.
Folia Primatol (Basel) ; 87(5): 291-302, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27894111

RESUMO

The grey slender loris Loris lydekkerianus, one of only two nocturnal primates of India, is found in the southern part of the country. Our understanding of its geographical distribution is largely based on historical records and short surveys, and little is known of its occurrence in southern India today. We sought to establish the relative abundance of this species in 26 districts in the state of Tamil Nadu and the union territory of Pondicherry in southern India. We sighted lorises in 19 districts, and their relative abundance ranged from 0.01 to 2.21/km. The south-central districts of Tamil Nadu showed the highest densities of lorises, while the western districts showed the lowest. Based on these results, we recommend increased protection measures for the forest patches of the Eastern Ghats mountains in order to ensure the long-term survival of the grey slender loris.


Assuntos
Lorisidae , Densidade Demográfica , Animais , Conservação dos Recursos Naturais , Ecossistema , Índia
2.
Braz J Microbiol ; 54(4): 3033-3039, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37723328

RESUMO

Microorganisms play a vital role in biological wastewater treatment by converting organic and toxic materials into harmless substances. Understanding microbial communities' structure, taxonomy, phylogeny, and metabolic activities is essential to improve these processes. Molecular microbial ecology employs molecular techniques to study community profiles and phylogenetic information since culture-dependent approaches have limitations in providing a comprehensive understanding of microbial diversity in a system. Genomic advancements such as DNA hybridization, microarray analysis, sequencing, and reverse sample genome probing have enabled the detailed characterization of microbial communities in wastewater treatment facilities. This mini-review summarizes the current state of knowledge on the diversity of microorganisms in wastewater treatment plants, emphasizing critical microbial processes such as nitrogen and phosphorus removal.


Assuntos
Microbiota , Águas Residuárias , Filogenia , Genômica , Nitrogênio/metabolismo , Fósforo/metabolismo , Reatores Biológicos/microbiologia , Esgotos/microbiologia
3.
Infect Dis Obstet Gynecol ; 2012: 950650, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22496602

RESUMO

BACKGROUND: We determined the consistency of positive interferon-gamma (IFN-γ) release assays (IGRAs) to detect latent TB infection (LTBI) over one-year postpartum in HIV-1-infected women. METHODS: Women with positive IGRAs during pregnancy had four 3-monthly postpartum IGRAs. Postpartum change in magnitude of IFN-γ response was determined using linear mixed models. RESULTS: Among 18 women with positive pregnancy IGRA, 15 (83%) had a subsequent positive IGRA; 9 (50%) were always positive, 3 (17%) were always negative, and 6 (33%) fluctuated between positive and negative IGRAs. Women with pregnancy IGRA IFN-γ>8 spot forming cells (SFCs)/well were more likely to have consistent postpartum IGRA response (odds ratio: 10.0; 95% confidence interval (CI): 0.9-117.0). Change in IFN-γ response over postpartum was 10.2 SFCs/well (95% CI: -1.5-21.8 SFCs/well). CONCLUSION: Pregnancy positive IGRAs were often maintained postpartum with increased consistency in women with higher baseline responses. There were modest increases in magnitude of IGRA responses postpartum.


Assuntos
Infecções por HIV/complicações , Testes de Liberação de Interferon-gama/normas , Interferon gama/análise , Mycobacterium tuberculosis/imunologia , Complicações Infecciosas na Gravidez/diagnóstico , Tuberculose/diagnóstico , Adulto , Feminino , HIV-1 , Humanos , Tuberculose Latente/diagnóstico , Gravidez
4.
Int J Pediatr Otorhinolaryngol ; 118: 42-46, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30578995

RESUMO

OBJECTIVE: To determine whether anesthesiologists need to rely on polysomnography (PSG) when predicting need for airway intervention during induction in patients with sleep-disordered breathing (SDB). METHODS: Prospective case-control observational study at a tertiary care pediatric hospital. Children between the ages of 2-17 undergoing tonsillectomy were divided into three groups: those presenting with OSA observed by history and/or physical examination alone (SDB; n = 33), those with OSA determined by preoperative PSG (OSA; n = 32), and a control group (n = 35) undergoing tonsillectomy for recurrent tonsillitis. An anesthesiologist ranked each case on the level of intervention required to maintain ventilation. RESULTS: Age, height and BMI were associated with greater induction difficulty (r's > .225, p's < .025). Compared to controls, induction difficulty was significantly greater for the SDB group (mean difference = -0.751, 95% confidence interval [CI] = -1.241, -0.261, p = .003), but not for the OSA group (p = .061). No significant difference in induction difficulty was observed between SDB and OSA groups. In a subgroup analysis of the OSA group, an apnea-hypopnea index (AHI) > 10 correlated with increased level of intervention during induction (r = .228, p = .022). Race was also associated with AHI >10 (odds ratio = 3.859, 95% CI = 1.485, 10.03, p = .006). CONCLUSION: Children with OSA undergoing tonsillectomy require more airway intervention during induction than children with recurrent tonsillitis. Age and BMI were correlated with greater induction difficulty, suggesting that PSG data should be considered in light of these clinical characteristics to ensure an optimal postoperative course for children undergoing tonsillectomy.


Assuntos
Anestesia Geral , Apneia Obstrutiva do Sono/complicações , Tonsilectomia , Fatores Etários , Índice de Massa Corporal , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Polissonografia , Período Pós-Operatório , Estudos Prospectivos , Índice de Gravidade de Doença , Síndromes da Apneia do Sono/complicações , Síndromes da Apneia do Sono/fisiopatologia , Apneia Obstrutiva do Sono/fisiopatologia , Tonsilite/cirurgia
5.
Biochim Biophys Acta ; 563(2): 527-33, 1979 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-572706

RESUMO

The nature of interaction of Rh(III) with DNA was studied using viscometry and ultraviolet, visible and infrared spectroscopy. The rate of interaction was found to be very slow at room temperature taking several days for completion. The time needed to attain equilibrium is dependent on the concentrations of metal ion, higher the concentration shorter the period required for equilibration. Visible spectra of Rh(III) were found to alter considerably in the presence of DNA. An increase in absorbance and a red shift were observed in the ultra violet spectra of DNA in the presence of Rh(III). The specific viscosity of DNA solution was found to decrease asymptotically with time and concentrations of metal ion. The melting temperature of DNA was found to increase at lower metal ion concentrations, whereas at higher values a decrease was obtained. At still higher metal ion concentrations (metal ion/DNA-P greater than 3) a 'nonmeltable state' of DNA was observed. These results seem to indicate that Rh(III) binds both with the phosphate and the bases of the DNA.


Assuntos
DNA , Ródio , Animais , Bovinos , Fenômenos Químicos , Química , Conformação de Ácido Nucleico , Desnaturação de Ácido Nucleico , Espectrofotometria , Timo , Viscosidade
6.
Biochim Biophys Acta ; 782(1): 55-66, 1984 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-6232953

RESUMO

The effect of binding a high mobility group protein (HMG 17) on the stability and conformation of acetylated and control HeLa high molecular weight core chromatin (stripped of H1 and non-histone chromosomal proteins) was studied by circular dichroism and thermal-denaturation measurements. Previously it had been shown that conformational differences exist between native whole chromatin derived from butyrate-treated (acetylated) and control HeLa cells and that these conformational differences disappear by removing H1 and non-histone chromosomal proteins ( Reczek , P.R., Weissman , D., Huvos , P.E. and Fasman, G.D. (1982) Biochemistry 21, 993-1002). The circular dichroism spectra and the thermal denaturation profiles of control and acetylated core chromatin were found to be similar. The circular dichroism properties of HMG 17 reconstituted highly acetylated and control core chromatin indicated the same alteration of chromatin structure at low ionic strength (1 mM sodium phosphate/0.25 mM EDTA, pH 7.0). The magnitudes of the decrease in ellipticity were proportional to the amount of HMG 17 bound and were found to be the same for both the acetylated and control core chromatin. Thermal denaturation profiles confirmed this change in structure induced by HMG 17 on control and highly acetylated core chromatin. The thermal denaturation profiles, which were resolved into three component transitions, exhibited a shifting of hyperchromicity from the lower melting transitions to the higher melting transitions, with a concomitant rise in Tm, on HMG 17 binding to both control and acetylated chromatin. The natures of the interactions of HMG 17 at higher ionic strength (50 mM NaCl/0.25 mM EDTA/1 mM sodium phosphate, pH 7.0) with acetylated and control core chromatin were slightly different, as measured by circular dichroism; however, a decrease in ellipticity was observed for both samples upon binding of HMG 17. These observations suggest that acetylation coupled with HMG 17 binding to core chromatin does not loosen chromatin structure. HMG 17 binding to control and acetylated core chromatin produces an overall stabilization and compaction of chromatin structure.


Assuntos
Acetilação , Química Orgânica , Cromatina/ultraestrutura , Proteínas Cromossômicas não Histona/fisiologia , Histonas/fisiologia , Butiratos/farmacologia , Ácido Butírico , Dicroísmo Circular , Células HeLa , Proteínas de Grupo de Alta Mobilidade , Temperatura Alta , Humanos , Desnaturação de Ácido Nucleico , Fenômenos de Química Orgânica , Concentração Osmolar , Ligação Proteica , Relação Estrutura-Atividade
7.
Diabetes ; 48(1): 77-85, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9892225

RESUMO

We have developed a panel of rabbit polyclonal antipeptide antibodies against the five human somatostatin receptor subtypes (hSSTR1-5) and used them to analyze the pattern of expression of hSSTR1-5 in normal human islet cells by quantitative double-label confocal fluorescence immunocytochemistry. All five hSSTR subtypes were variably expressed in islets. The number of SSTR immunopositive cells showed a rank order of SSTR1 > SSTR5 > SSTR2 > SSTR3 > SSTR4. SSTR1 was strongly colocalized with insulin in all beta-cells. SSTR5 was also an abundant isotype, being colocalized in 87% of beta-cells. SSTR2 was found in 46% of beta-cells, whereas SSTR3 and SSTR4 were relatively poorly expressed. SSTR2 was strongly colocalized with glucagon in 89% of alpha-cells, whereas SSTR5 and SSTR1 colocalized with glucagon in 35 and 26% of alpha-cells, respectively. SSTR3 was detected in occasional alpha-cells, and SSTR4 was absent. SSTR5 was preferentially expressed in 75% of SST-positive cells and was the principal delta-cell SSTR subtype, whereas SSTR1-3 were colocalized in only a few delta-cells, and SSTR4 was absent. These studies reveal predominant expression of SSTR1, SSTR2, and SSTR5 in human islets. Beta-cells, alpha-cells, and delta-cells each express multiple SSTR isoforms, beta-cells being rich in SSTR1 and SSTR5, alpha-cells in SSTR2, and delta-cells in SSTR5. Although there is no absolute specificity of any SSTR for an islet cell type, SSTR1 is beta-cell selective, and SSTR2 is alpha-cell selective. SSTR5 is well expressed in beta-cells and delta-cells and moderately well expressed in alpha-cells, and thereby it lacks the islet cell selectivity displayed by SSTR1 and SSTR2. Subtype-selective SSTR expression in islet cells could be the basis for preferential insulin suppression by SSTR1-specific ligands and of glucagon inhibition by SSTR2-selective compounds.


Assuntos
Ilhotas Pancreáticas/metabolismo , Receptores de Somatostatina/metabolismo , Animais , Linhagem Celular , Glucagon/metabolismo , Humanos , Imuno-Histoquímica , Insulina/metabolismo , Ilhotas Pancreáticas/citologia , Isomerismo , Coelhos , Somatostatina/metabolismo , Especificidade por Substrato , Distribuição Tecidual
8.
Gene ; 214(1-2): 45-9, 1998 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-9651476

RESUMO

The human somatostatin receptor subtype 5 (hSSTR5) gene has previously been cloned and localized to chromosome 16 p13.3. This region is evolutionarily conserved in all vertebrate genomes from the puffer fish (Fugu rubripes) to human, and also contains loci for genes associated with two common multisystemic disorders, adult polycystic kidney disease (PKD1) and tuberous sclerosis (TSC2). Analysis of the 5' flanking region of the hSSTR5 gene has revealed consensus sequences for a number of transcription factors as well as Alu-like repeat elements. In the present study, genomic DNA from 53 unrelated individuals was analysed by PCR and Southern blots probed with radiolabeled fragments generated from different segments of the hSSTR5 gene. We have identified two restriction fragment length polymorphisms (RFLP) with high heterozygosity values at the 5' flanking region of the hSSTR5 gene. These RFLP markers will be useful for determining the allelic loss of genetic material from this region. The observed polymorphism in the promoter region may affect the function of the hSSTR5 gene.


Assuntos
Polimorfismo de Fragmento de Restrição , Receptores de Somatostatina/genética , Adulto , Animais , Sequência de Bases , Cromossomos Humanos Par 16/genética , DNA/genética , DNA/isolamento & purificação , Primers do DNA/genética , Evolução Molecular , Expressão Gênica , Genes Reguladores , Humanos , Perda de Heterozigosidade , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase
9.
Am J Med Genet ; 37(1): 71-8, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2240047

RESUMO

A 17-year-old girl (S.M.) and a 13-year-old girl (C.L.) both with Ullrich-Turner syndrome (UTS) were found to have 45,X/46,X, + mar mosaicism. The marker chromosomes in both patients were very small in size. In S.M. the marker chromosome was present in 80% of phytohemagglutinin-stimulated lymphocytes, 28% of skin fibroblasts, and 11-20% of gonadal fibroblasts. In C.L., the small marker chromosome was found in 50% of stimulated lymphocytes. S.M. is of normal height, but C.L. is short. Molecular hybridization with a number of Y-specific DNA probes demonstrated their presence in S.M. but absence in C.L. In situ hybridization with Y-specific and X-centromere-specific DNA probes confirmed the Y origin of the marker chromosome in S.M. and the X origin of the minute chromosome in C.L. Biotinylated centromere and telomere probes were also used for in situ hybridization to show the presence of centromeric and telomeric sequences in the Y-marker chromosome, suggesting that the deletion of this marker chromosome is interstitial.


Assuntos
Mosaicismo , Síndrome de Turner/genética , Cromossomo X , Adolescente , Sondas de DNA , Feminino , Marcadores Genéticos , Humanos , Hibridização de Ácido Nucleico , Cromossomos em Anel , Cromossomo Y
10.
Cancer Genet Cytogenet ; 51(2): 239-54, 1991 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1704295

RESUMO

Two new breast tumor cell lines (UISO-BC-1 and UISO-BC-2) have been established from pleural effusions obtained from patients with confirmed diagnosis of breast cancer. Cytogenetic investigation shows several numerical and structural aberrations in both cell lines. Each cell line appears to have distinctive karyotypic aberrations. Although a common marker chromosome was not found in both cell lines, several breakpoints (i.e., 1q11, 3q11, 7p11, 9q11, and 13q11) were commonly involved in the marker chromosomes of both lines. Double minute (dmin) chromosomes were also observed in these two cell lines. Sixteen oncogene probes were used to study the oncogene amplification and overexpression; among these, only neu and c-myc probes detected multiple gene copies. A 10-fold amplification and a 20-fold overexpression of the neu were observed in the UISO-BC-1 line, whereas a threefold and a fivefold amplification of c-myc were found in UISO-BC-1 and UISO-BC-2, respectively. Moderately enhanced expression (sixfold) of c-myc was also observed in the UISO-BS-2 line. No gross rearrangement of these genes or aberrant RNAs was detected in these tumor cell lines.


Assuntos
Neoplasias da Mama/genética , Carcinoma Intraductal não Infiltrante/genética , Carcinoma de Células Escamosas/genética , Aberrações Cromossômicas/genética , Oncogenes/genética , Idoso , Northern Blotting , Southern Blotting , DNA/análise , Sondas de DNA , Feminino , Amplificação de Genes , Humanos , Cariotipagem , RNA/análise , Células Tumorais Cultivadas
11.
Pediatr Infect Dis J ; 33(4): 401-6, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24378937

RESUMO

BACKGROUND: Infants born to HIV-1 infected mothers may have increased risk for tuberculosis (TB), but the prevalence of TB infection in this population is undefined. In contrast to tuberculin skin tests that are confounded by recent bacille Calmette-Guérin (BCG) vaccination, TB interferon gamma release assays (IGRAs) do not cross-react with BCG and enable detection of TB infection in infancy. METHODS: In a nested observational cohort of HIV-1 infected Kenyan mothers and their infants, we conducted T-SPOT.TB assays on cryopreserved peripheral blood mononuclear cells from 6-month-old infants without prior active TB. Maternal and infant correlates of infant TB infection were assessed. RESULTS: One hundred and eight-two infants were tested with T-SPOT.TB. Of 128 infants with determinate T-SPOT.TB results, the prevalence of a positive T-SPOT.TB was 10.9% [95% confidence interval (CI): 6.1-17.7%]. All infants were BCG-vaccinated and 7.0% were HIV-1 infected. Positive infant T-SPOT.TB was associated with maternal active TB (odds ratio: 15.5, 95% CI: 1.3-184; P = 0.04) and prolonged infant fever (>1 month) (odds ratio: 18.8, 95% CI: 1.6-223; P = 0.03). CONCLUSIONS: We observed a high prevalence of TB infection in 6-month-old HIV-1 exposed infants. Improved TB detection and prevention are warranted in HIV-1 exposed infants at high risk for active TB disease.


Assuntos
Infecções por HIV/microbiologia , HIV-1 , Tuberculose/virologia , Adulto , Estudos de Coortes , Feminino , Infecções por HIV/sangue , Infecções por HIV/epidemiologia , Humanos , Lactente , Testes de Liberação de Interferon-gama , Quênia/epidemiologia , Leucócitos Mononucleares/microbiologia , Exposição Materna , Mães/estatística & dados numéricos , Tuberculose/sangue , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Adulto Jovem
14.
Breast Cancer Res Treat ; 92(2): 175-86, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15986128

RESUMO

Somatostatin receptors (SSTRs) have been identified in most hormone-producing tumors as well as in breast cancer. In the present study, we determined SSTR1-5 expression in primary ductal NOS breast tumors through semi-quantitative RT-PCR and immunocytochemistry. The results from the analysis of 98 samples were correlated with several key histological markers and receptor expression. All five SSTR subtypes are variably expressed at the mRNA level in breast tumors with 91% of samples showing SSTR1, 98% SSTR2, 96% SSTR3, 76% SSTR4, and 54% SSTR5. SSTR1-5 are localized to both tumor cells and the surrounding peritumoral regions as detected by immunocytochemistry. Levels of SSTR mRNA, when corrected for beta-actin levels, were highest for SSTR3 followed by SSTR1, SSTR2, SSTR5, and SSTR4. Furthermore, there was good correlation between mRNA and protein expression with 84% for SSTR1, 79% for SSTR2, 89% for SSTR3, 68% for SSTR4, 68% for SSTR5, and 78% for all five receptors. SSTR1, 2 and 4 were correlated with ER levels whereas SSTR2 showed an additional correlation with PR levels. These correlations were independent of patient age and histological grade. Moreover, using immunocytochemistry, blood vessels exhibited receptor-specific localization for SSTR2 and SSTR5. Our results indicate significant correlations between mRNA and protein expression along with receptor-specific correlations with histological markers as well as ER and PR levels. Differential distribution of SSTR subtypes in tumors and receptor-specific expression in vascular structures may be considered as a novel diagnosis for breast tumors with receptor subtype agonists.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Receptores de Somatostatina/metabolismo , Adulto , Idoso , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/genética , Carcinoma Ductal de Mama/genética , Feminino , Expressão Gênica , Humanos , Imuno-Histoquímica , Técnicas In Vitro , Pessoa de Meia-Idade , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Neoplásico/análise , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Receptores de Somatostatina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
15.
Clin Invest Med ; 17(5): 474-98, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7867253

RESUMO

In the past 10 y, there have been considerable advances in the mapping, isolation, and characterization of many genes for important ocular conditions: retinitis pigmentosa, Norrie disease, Waardenburg syndrome, choroideremia, aniridia, retinoblastoma, and others. The candidate gene approach has now supplemented classical linkage studies and positional cloning in the investigation of ocular disorders. Developmentally expressed genes and animal models have provided insights as to the etiology of other disorders. With this knowledge at hand, genetic counselling for heritable eye diseases has been greatly improved.


Assuntos
Oftalmopatias Hereditárias/genética , Animais , Humanos
16.
J Clin Lab Anal ; 5(3): 193-6, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-2061743

RESUMO

Specific amplification of a DNA segment of the human ZFY gene by polymerase chain reaction (PCR) was carried out for detection of Y-chromosome specific sequences. When male DNA was used as template for amplification, a single and discrete 530 bp ethidium bromide staining band was observed in agarose gel. Female DNA produced no band. This technique was successfully used in prenatal sexing and for detecting ZFY DNA sequences in five XX males, an XY female, and a female patient with Turner syndrome having mosaicism involving a minute marker chromosome.


Assuntos
Reação em Cadeia da Polimerase/métodos , Diagnóstico Pré-Natal/métodos , Aberrações dos Cromossomos Sexuais/diagnóstico , Cromossomo Y , Sequência de Bases , Feminino , Humanos , Cariotipagem , Masculino , Dados de Sequência Molecular , Técnicas de Amplificação de Ácido Nucleico , Análise para Determinação do Sexo , Síndrome de Turner/diagnóstico
17.
Biochemistry ; 25(8): 1981-8, 1986 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-3707925

RESUMO

Chicken erythrocyte chromatin was prepared according to two different methods [Fulmer, A. W., & Bloomfield, V. A. (1981) Proc. Natl. Acad. Sci. U.S.A. 78, 5968-5972; Ausio, J., Borochov, N., Seger, D., & Eisenberg, H. (1984) J. Mol. Biol. 177, 373-398] to give three main common fractions, according to its solubility (S) or insolubility (I) in 0.15 M NaCl buffers or to its further solubility in 0.25 mM ethylenediaminetetraacetic acid (E). From the biochemical point of view, all of them have been found to be undistinguishable. Analytical ultracentrifugation shows that all of these fractions can reversibly undergo the transition from the low to the higher order structure, through a nearly identical way of folding. Thermal denaturation profiles yielded three transitions having the same Tm's for the three fractions. The percentage of DNA melting in the first transition decreased in the order S greater than I greater than E, and the amount in the second transition increased in the same order. Together with the different solubility of these fractions in the presence of divalent ions, these results indicate that in the three fractions of chromatin studied, the amount of linker DNA bound to the nucleosome varied.


Assuntos
Núcleo Celular/ultraestrutura , Cromatina/ultraestrutura , Eritrócitos/ultraestrutura , Animais , Galinhas , Cromatina/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Histonas/sangue , Histonas/isolamento & purificação , Radioisótopos do Iodo , Magnésio , Cloreto de Magnésio , Peso Molecular , Nucleossomos/ultraestrutura , Solubilidade
18.
J Biol Chem ; 257(19): 11448-54, 1982 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-6214552

RESUMO

The nature of the binding of a high mobility group protein (HMG 17) to native and H1-H5-depleted chicken erythrocyte chromatin was studied, as a function of ionic strength, using circular dichroism and thermal denaturation techniques. The circular dichroism properties of the HMG 17-reconstituted whole chromatin and H1-H5-depleted chromatin demonstrated that a condensation of chromatin structure occurred upon HMG 17 binding at low ionic strength (1 mM Na phosphate, 0.25 mM EDTA, pH 7.0). Thermal denaturation profiles confirmed this change in the structure of chromatin induced by HMG 17. Thermal denaturation profiles were resolved into three-component transitions. In general, a shift in the temperature of maximum dh/dT for each transition (Tm) was observed for all transitions upon HMG 17 binding. DNA melting in the first transition, originating from linker regions of whole chromatin, was nearly totally depleted and was distributed mainly into the highest melting transition. The same trends were also observed in H1-H5-depleted chromatin. These results indicate that the binding sites of HMG 17 are situated in the linker regions immediately adjacent to the core. The nature of the interaction of HMG 17 at higher ionic strength (50 mM NaCl, 1 mM Na phosphate, 0.25 mM EDTA, pH 7.0) with whole chromatin and H1-H5-depleted chromatin was found to be different but a decrease in [theta] values was found in both chromatins. These observations suggest that HMG 17 does not loosen chromatin structure but produces an overall stabilization and condensation of structure. The implications of these results to the currently accepted models of transcriptionally active chromatin are discussed.


Assuntos
Cromatina/metabolismo , Proteínas Cromossômicas não Histona/sangue , Animais , Galinhas , Proteínas Cromossômicas não Histona/isolamento & purificação , Dicroísmo Circular , Eritrócitos/metabolismo , Proteínas de Grupo de Alta Mobilidade , Histonas/sangue , Ligação Proteica , Conformação Proteica
19.
Cytogenet Cell Genet ; 63(3): 156-9, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8485991

RESUMO

The Indian muntjac is believed to have the lowest chromosome number in mammals (2n = 6 in females and 2n = 7 in males). It has been suggested that a series of tandem chromosome fusions from an ancestral Chinese muntjac-like species (2n = 46) may have occurred during the karyotypic evolution of the Indian muntjac. In an earlier study, hybridization signals generated by the Chinese muntjac centromeric heterochromatin DNA probe (C5) were found to be distributed interstitially in the chromosomes of the Indian muntjac, providing supportive evidence for the tandem chromosome fusion theory. In this study, the highly conserved human telomeric DNA sequence (TTAGGG)n was localized by fluorescence in situ hybridization (FISH) on the metaphase chromosomes of three Cervidae species: the Indian muntjac, Chinese muntjac, and woodland caribou. As expected, hybridization signals were observed at the termini of almost every chromosome in all three species. In addition, interstitial hybridization signals were detected in chromosomes 1 and 2 of the Indian muntjac. The observed interstitial telomeric signals appeared to correspond to specific interstitial centromeric heterochromatin sites. These interstitial telomeric signals could represent remnant DNA sequences from the ancestral species telomeres, further supporting the tandem chromosome fusion theory. Furthermore, these observations permit the elucidation of the chromosome sites where breakage and fusion most likely occurred during the restructuring of the ancestral Chinese muntjac-like chromosomes to form the present day Indian muntjac karyotype.


Assuntos
Cromossomos/ultraestrutura , Cervos/genética , Telômero/química , Animais , Sequência de Bases , Evolução Biológica , Heterocromatina/ultraestrutura , Hibridização In Situ , Cariotipagem
20.
Genomics ; 14(2): 542-5, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1427877

RESUMO

Fifty cosmids have been mapped to metaphase chromosomes by fluorescence in situ hybridization under conditions that suppress signals from repetitive DNA sequences. The cosmid clones were isolated from a flow-sorted human X chromosome library. Thirty-eight of the clones were localized to chromosome X and 12 to autosomes such as chromosomes 3, 7, 8, 14, and 17. Although most of the cosmids mapped to the X chromosome appeared to be scattered along both the short and long arms, 10 cosmids were localized to the centromeric region of the chromosome. Southern blot analysis revealed that only two of these clones hybridized to probe pXBR-1, which detects the DXZ1 locus. In addition, 4 out of 5 cosmids mapped on chromosome 8 also localized on the centromeric region. While localization of X-specific cosmids will facilitate the physical mapping of the human X chromosome, cosmids mapped to the centromeric regions of chromosomes X and 8 should be especially useful for studying the structure and organization of these regions.


Assuntos
Cosmídeos , Cromossomo X , Southern Blotting , Mapeamento Cromossômico , Citometria de Fluxo , Biblioteca Genômica , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Metáfase
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