RESUMO
Epigenetic modifications in histones are crucial for proper sperm physiology, egg activation and reproductive development of males. The objectives of this study were to determine the conservation and interactomes of histone three (H3) and ascertain the expression dynamics of acetylated and methylated H3 lysine 27 (H3K27ac and H3K27me3) in spermatozoa from Holstein bulls with different fertility. Methods in immunocytochemistry and flow cytometry were used to evaluate the expression dynamics of H3K27ac and H3K27me3 in spermatozoa from 10 bulls with different in vivo fertility. Computational biology methods including Clustal Omega and Cytoscape were performed to determine the evolutionary conservation and interactome of H3. The post-translational modifications (PTM) of H3 (H3K27ac and H3K27me3) had different spatiotemporal dynamics in the sperm head. Intensities of methylation were higher than those of acetylation and inversely correlated between the two fertility groups (p = .0032). The interacting proteins of H3 are involved in critical subcellular processes such as regulation of methylation, nucleosome assembly, regulation of DNA replication and chromatin assembly. These results are significant because they help advance fundamental science and biotechnology of mammalian reproduction.
Assuntos
Metilação de DNA , Fertilidade/fisiologia , Histonas/metabolismo , Espermatozoides/metabolismo , Acetilação , Animais , Bovinos , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , Lisina , MasculinoRESUMO
BACKGROUND: The aim of this study was to evaluate the impact of Surgical Unit volume on the 30-day reoperation rate in patients with CRC. METHODS: Data were extracted from the regional Hospital Discharge Dataset and included patients who underwent elective resection for primary CRC in the Veneto Region (2005-2013). The primary outcome measure was any unplanned reoperation performed within 30 days from the index surgery. Independent variables were: age, gender, comorbidity, previous abdominal surgery, site and year of the resection, open/laparoscopic approach and yearly Surgical Unit volume for colorectal resections as a whole, and in detail for colonic, rectal and laparoscopic resections. Multilevel multivariate regression analysis was used to evaluate the impact of variables on the outcome measure. RESULTS: During the study period, 21,797 elective primary colorectal resections were performed. The 30-day reoperation rate was 5.5% and was not associated with Surgical Unit volume. In multivariate multilevel analysis, a statistically significant association was found between 30-day reoperation rate and rectal resection volume (intermediate-volume group OR 0.75; 95% CI 0.56-0.99) and laparoscopic approach (high-volume group OR 0.69; 95% CI 0.51-0.96). CONCLUSIONS: While Surgical Unit volume is not a predictor of 30-day reoperation after CRC resection, it is associated with an early return to the operating room for patients operated on for rectal cancer or with a laparoscopic approach. These findings suggest that quality improvement programmes or centralization of surgery may only be required for subgroups of CRC patients.
Assuntos
Colectomia/estatística & dados numéricos , Neoplasias Colorretais/cirurgia , Unidades Hospitalares/estatística & dados numéricos , Centro Cirúrgico Hospitalar/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Colectomia/métodos , Procedimentos Cirúrgicos Eletivos/métodos , Procedimentos Cirúrgicos Eletivos/estatística & dados numéricos , Feminino , Humanos , Itália , Laparoscopia/métodos , Laparoscopia/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Análise de Regressão , Reoperação/estatística & dados numéricos , Adulto JovemRESUMO
Endometriosis is a common gynaecological condition which affects women during their reproductive years. It is characterized by ectopic endometrial tissue responding to hormonal changes associated with menstrual cycle. Aetiology is unknown and symptoms are quite aspecific (dysmenorrhoea, pelvic pain, infertility or pelvic mass). Ultrasonography (US) and Magnetic Resonance Imaging (MRI) are accurate diagnostic exams but laparoscopy represents the gold standard in diagnosis and therapy (excision or ablation). Medical treatment pre or postoperatively may be useful prolonging the symptom free interval. In this paper we report the case of a young woman affected by an inguinal mass: diagnostic examinations and histological specimen revealed to be an endometrial focus. We review the literature focusing the diagnostic techniques and relationships between endometriosis and ovarian cancer (endometrioid and clear cell subtypes).
Assuntos
Endometriose , Canal Inguinal , Adulto , Endometriose/diagnóstico , Endometriose/cirurgia , Feminino , HumanosRESUMO
Mesenteric and retroperitoneal cysts are rare intra-abdominal tumours with an incidence of 1/140.000 in surgery departments and 1/20.000 in paediatric departments. There are no pathognomonic signs or symptoms for the cysts. In the differential diagnosis lymphangiomas, sarcomas, adenocarcinomas and intestinal duplications should be considered. Diagnostic includes abdominal computed tomography, ultrasound and MRI. Barium enema examination or intravenous pyelogram may be used in special cases. Surgical treatment is indicated also in asymptomatic patients; laparoscopic approach is the "gold standard". Laparotomic approach should be used in the cases of impossibility of total enucleation or in the cases of malignant degeneration. Complete enucleation is the treatment of choice for retroperitoneal and mesenteric cysts. If this cannot be accomplished, the alternative should be the excision of the cyst or the marsupialization. In this paper we present a case of young man with a mesenteric cyst mimicking acute appendicitis.
Assuntos
Cisto Mesentérico/diagnóstico , Cisto Mesentérico/cirurgia , Adolescente , Apendicectomia , Apendicite/diagnóstico , Apendicite/cirurgia , Diagnóstico Diferencial , Humanos , Cuidados Intraoperatórios , Masculino , Reoperação , Resultado do TratamentoRESUMO
BACKGROUND AND AIMS: The clone EMB-2 of the interspecific hybrid Helianthus annuus x H. tuberosus provides an interesting system to study molecular and physiological aspects of somatic embryogenesis. Namely, in addition to non-epiphyllous (NEP) leaves that expand normally, EMB-2 produces epiphyllous (EP) leaves bearing embryos on the adaxial surface. This clone was used to investigate if the ectopic expression of H. annuus LEAFY COTYLEDON1-LIKE (Ha-L1L) gene and auxin activity are correlated with the establishment of embryogenic competence. METHODS: Ha-L1L expression was evaluated by semi-quantitative RT-PCR and in situ hybridization. The endogenous level and spatial distribution of free indole-3-acetic acid (IAA) were estimated by a capillary gas chromatography-mass spectrometry-selected ion monitoring method and an immuno-cytochemical approach. KEY RESULTS: Ectopic expression of Ha-L1L was detected in specific cell domains of the adaxial epidermis of EP leaves prior to the development of ectopic embryos. Ha-L1L was expressed rapidly when NEP leaves were induced to regenerate somatic embryos by in vitro culture. Differences in auxin distribution pattern rather than in absolute level were observed between EP and A-2 leaves. More precisely, a strong IAA immuno-signal was detected in single cells or in small groups of cells along the epidermis of EP leaves and accompanied the early stages of embryo development. Changes in auxin level and distribution were observed in NEP leaves induced to regenerate by in vitro culture. Exogenous auxin treatments lightly influenced Ha-L1L transcript levels in spite of an enhancement of the regeneration frequency. CONCLUSIONS: In EP leaves, Ha-L1L activity marks the putative founder cells of ectopic embryos. Although the ectopic expression of Ha-L1L seems to be not directly mediated by auxin levels per se, it was demonstrated that localized Ha-L1L expression and IAA accumulation in leaf epidermis domains represent early events of somatic embryogenesis displayed by the epiphyllous EMB-2 clone.
Assuntos
Cruzamentos Genéticos , Desenvolvimento Embrionário , Genes de Plantas , Helianthus/embriologia , Helianthus/genética , Ácidos Indolacéticos/metabolismo , Folhas de Planta/genética , Desenvolvimento Embrionário/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Helianthus/efeitos dos fármacos , Hibridização Genética/efeitos dos fármacos , Ácidos Indolacéticos/farmacologia , Epiderme Vegetal/citologia , Epiderme Vegetal/efeitos dos fármacos , Epiderme Vegetal/genética , Folhas de Planta/citologia , Folhas de Planta/efeitos dos fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Regeneração/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica/efeitos dos fármacosRESUMO
This study considered cytokinin distribution in tobacco (Nicotiana tabacum L.) shoot apices in distinct phases of development using immunocytochemistry and quantitative tandem mass spectrometry. In contrast to vegetative apices and flower buds, we detected no free cytokinin bases (zeatin, dihydrozeatin, or isopentenyladenine) in prefloral transition apices. We also observed a 3-fold decrease in the content of cytokinin ribosides (zeatin riboside, dihydrozeatin riboside, and isopentenyladenosine) during this transition phase. The group concluded that organ formation (e.g. leaves and flowers) is characterized by enhanced cytokinin content, in contrast to the very low endogenous cytokinin levels found in prefloral transition apices, which showed no organogenesis. The immunocytochemical analyses revealed a differing intracellular localization of the cytokinin bases. Dihydrozeatin and isopentenyladenine were mainly cytoplasmic and perinuclear, whereas zeatin showed a clear-cut nuclear labeling. To our knowledge, this is the first time that this phenomenon has been reported. Cytokinins do not seem to act as positive effectors in the prefloral transition phase in tobacco shoot apices. Furthermore, the differences in distribution at the cellular level may be indicative of a specific physiological role of zeatin in nuclear processes.
RESUMO
Between 1968 and 1982, 13 patients in this study had a pancreaticoduodenectomy (PD), one patient had a total pancreatectomy, two had an ampullectomy, and one patient had a choledochoduodenostomy for neoplasia of the ampulla of Vater. The operative mortality was zero, and the 5-year actuarial survival rate for the 16 resected patients was 52.6 per cent. From a review of the literature, the authors evaluated 1,894 PDs and 61 ampullectomies. The operative mortality rate was 14 per cent and 3 per cent, respectively. The 5-year survival rate was 21 per cent for PD and 23 per cent for ampullectomy. However, 187 patients with negative lymph nodes who underwent PD had a 5-year survival rate of 39 per cent. PD resection is fully warranted for ampullary tumors. Ampullectomy should be reserved only for high surgical risk patients.
Assuntos
Adenocarcinoma/cirurgia , Ampola Hepatopancreática , Neoplasias do Ducto Colédoco/cirurgia , Feminino , Humanos , Masculino , Pancreatectomia/mortalidade , Fístula Pancreática/etiologia , Complicações Pós-Operatórias/etiologiaRESUMO
Chronic pancreatitis appears to be increasing likely because increase in alcohol consumption and improved diagnostic tools. So the diabetes due to chronic pancreatitis is gaining importance. In order to obtain a better understanding of that particular secondary diabetes, 179 patients with chronic pancreatitis were studied from 1970 to 1981. 154 patients were male and 25 female. Average admission age was 45, ranging from 25 to 86. All the patients underwent medical therapy, based on diet, pancreatic enzymes, pain control. 99 of them underwent even to surgery. The follow-up is ranging from 6 months to 10 years: during this period 18 patients died, 41 went lost. 120 patients are still under observation. Diabetes was found in the family history of 27 patients (15%). At hospital admission 41 patients (23%) had high fasting glycemia, 23 of them even glycosuria. Other 74 showed diabetic oral glucose tolerance test. During the follow-up time 27 became clinically diabetic, 3 died because hyperosmolar coma and 8 had to be readmitted more than once because diabetic metabolic decompensation. Among the 120 patients at the moment under control, 66 (55%) show abnormal fasting glycemia, 10 developed high blood pressure, 12 inferior limbs vasculopathy with paresthesias and intermittent claudication, 2 myocardiosclerosis and atrial fibrillation, 1 myocardial infarction, 2 chronic nephropathy, 1 diabetic retinopathy. Whereas surgery or medic therapy may relieve chronic pancreatitis typical symptoms, they appear to be useless remedy against the under lying diabetes. As the time goes on more and more patients develop glucose intolerance, quite early became insulin-dependent, are disposed to severe diabetic metabolic decompensation and can show vascular, cardiac or renal complication.
Assuntos
Diabetes Mellitus/etiologia , Pancreatite/complicações , Adulto , Idoso , Colelitíase/etiologia , Doença Crônica , Diabetes Mellitus/dietoterapia , Feminino , Seguimentos , Humanos , Hiperglicemia/etiologia , Insulina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Pancreatectomia , Extratos Pancreáticos/uso terapêutico , Pseudocisto Pancreático/etiologia , Pancreatite/terapiaRESUMO
We here in present twenty myotonic dystrophy of Steinert patients with the main objective to evaluate and classify the oropharyngeal swallowing by the phonoaudiological clinical and nasofibrolaryngoscopical analysis. The age of the patients varied from 12 to 53 years, being 13 male and 7 female. The mean data: (1) statistically significant relation between the phonoaudiological clinical evaluation and nasofibrolaryngoscopical one; (2) stomatognatical system disorders present in 100%; (3) swallowing disorders present in 95%, when clinically evaluated, and in 70% when evaluated by the nasofibrolaryngoscopy; (4) higher difficulty to swallow consistent feed; (5) stomatognatical muscles very altered, pharyngeal phase disorders, cough after swallowing, antecedents of pneumonia and complaints of chewing/swallowing presented statistically significant correlation with severity of the sickness. The analysis were able to evaluate statical and functionally the involved structures in the swallowing, having got to take part of the routine of attendance to the patients with myotonic dystrophy of Steinert.
Assuntos
Transtornos de Deglutição/fisiopatologia , Laringoscopia/métodos , Distrofia Miotônica/fisiopatologia , Orofaringe/fisiopatologia , Doenças Faríngeas/fisiopatologia , Fala/fisiologia , Adolescente , Adulto , Criança , Deglutição/fisiologia , Transtornos de Deglutição/classificação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Distrofia Miotônica/diagnóstico , Doenças Faríngeas/classificação , Prognóstico , Sistema Estomatognático/fisiopatologiaRESUMO
The authors describe the technique for the treatment of gallbladder stones using a laparoscopic approach and discuss the diagnostic and operative flow chart stressing complications and ways to avoid them. A total of 2517 non-selected patients underwent surgery since october 1990 up to september 1995. 252 were affected by acute cholecystitis (10%); 172 underwent emergency laparoscopic cholecystectomy. ERCP was performed in 278 patients (11.04%): 177 underwent endoscopic sphincterotomy and laparoscopic cholecystectomy, 21 underwent laparoscopic cholecystectomy before sphincterotomy, 8 laparoscopic cholecystectomy and ESWL. Laparoscopic cholecystectomy was converted into laparotomy in 37 patients (1.4%); surgery was abandoned in 3 patients following to onset of intense bradycardia. Major complications were observed in 0.63%; bile duct injury occurred in four patients (0.15%). One patient died following a massive intraoperative myocardial infarction. Average operative time was 21 minutes. Only 22.8% of patients required mild analgesia on the first day after surgery. The average hospital postoperative stay was 2.6 days. Return to work took place in 98% of non complicated patients within one week of being discharged from hospital.
Assuntos
Colecistectomia Laparoscópica , Colelitíase/cirurgia , Colecistectomia Laparoscópica/efeitos adversos , Colecistectomia Laparoscópica/instrumentação , Colecistectomia Laparoscópica/métodos , Colecistectomia Laparoscópica/normas , Feminino , Humanos , Gravidez , Complicações na Gravidez/cirurgiaRESUMO
Different methods have been proposed for the management of intractable Ménière's disease. Over the past years a selection has been made based on the effectiveness and the side effects of the surgical techniques and only a few procedures are routinely used in modern practice. After a period of success, endolymphatic sac surgery is now being progressively abandoned in the aftermath of criticism on its real effectiveness. Vestibular neurectomy is considered an effective method for relieving vertigo but it is an invasive procedure and the risk of complications is not absent. Transtympanic gentamicin is now considered a real alternative approach to the treatment of vertigo in Ménière's disease. The literature reports a high incidence of success with this method, similar to that of vestibular neurectomy, and the only complication being some hearing loss encountered in a few cases. Strategies differ in the gentamicin treatment of Ménière's disease. In the past gentamicin was administered on a daily basis until an effect on the labyrinth was seen. Recently some authors have administered lower amounts of gentamicin for just two or there days. Such treatment appears to control vertigo equally well without causing labyrinthine areflexia although this is not supported in the literature by prolonged follow-ups. The authors discuss the results obtained with a low dosage transtympanic administration of gentamicin in a series of 29 patients followed up for two years. The impact of this form of therapy on quality of life was evaluated through a questionnaire prepared following the criteria of the American Academy of Otolaryngology Head and Neck Surgery. In all cases, the score improved at the end of follow-up.
Assuntos
Gentamicinas/administração & dosagem , Doença de Meniere/tratamento farmacológico , Qualidade de Vida , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Membrana Timpânica , Adulto JovemRESUMO
Eleven patients underwent choledochoduodenostomy under laparoscopic control: 5 for adenocarcinoma of head of pancreas, including 2 with extension into duodenum, 3 for chronic pancreatitis. 1 for gastric carcinoma with pancreatic infiltration 1 for carcinoma of ampulla and 1 for stenosing papillitis. Mean duration of operation was 97.9 minutes and mean hospital stay 7.8 days. No immediate or delayed postoperative complications were reported. The advantages of this method are the marked reduction in recovery time, especially in severely debilitated elderly patients, and the absence of postoperative pain.
Assuntos
Ducto Colédoco/cirurgia , Duodeno/cirurgia , Laparoscopia , Adenocarcinoma/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anastomose Cirúrgica/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/secundário , Neoplasias Pancreáticas/cirurgia , Pancreatite/cirurgia , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgiaRESUMO
A total of 92 patients were submitted to laparoscopic cholecystectomy during the period Autumn 1990-Spring 1991. The dissection of the gallbladder from the hepatic bed was performed in 40 patients using the Argon beam coagulator, in 25 using the monopolar electrocoagulator and in 27 using the Holmio laser beam. In average, with the Argon beam coagulator time procedure was respectively 2.7 and 5.4 minutes shorter than monopolar electrocoagulator and Holmio laser. Only one complication (pneumomediastinum) was correlated with the use of the Argon beam coagulator.
Assuntos
Colecistectomia/métodos , Laparoscopia , Fotocoagulação , Adulto , Idoso , Eletrocoagulação , Estudos de Avaliação como Assunto , Feminino , Humanos , Fotocoagulação/efeitos adversos , Masculino , Pessoa de Meia-Idade , Fatores de TempoRESUMO
We report our first experience with a laparoscopic treatment of congenital choledochal cysts involving the total cyst resection and the reconstruction of the biliary and gastrointestinal tracts through a transmesocolic hepatic-jejunal Roux-en-Y loop anastomosis. The procedure was carried out in a 14-kg 6-year-old girl with a congenital choledochal cyst of the first type, according to the Alonso-Lej classification. The cyst was divided using a Multifire EndoGIA 30 stapler. Hepatic-jejunal and jejunojejunal anastomoses were made with 4.0 chrome catgut interrupted sutures. Intestinal recanalization occurred on the 2nd postoperative day and the postoperative course was uneventful. The laparoscopic approach affords several advantages: excellent intraoperative visualization of tiny structures and, therefore, great surgical accuracy; early resumption of peristalsis; no postoperative pain; no laparocele; prevention of adhesions; excellent esthetics; and quicker resumption of school and sports activities.
Assuntos
Cisto do Colédoco/cirurgia , Laparoscópios , Gravação em Vídeo/instrumentação , Anastomose em-Y de Roux/instrumentação , Anastomose Cirúrgica/instrumentação , Criança , Feminino , Humanos , Jejuno/cirurgia , Testes de Função Hepática , Complicações Pós-Operatórias/etiologia , Grampeadores Cirúrgicos , Técnicas de Sutura/instrumentaçãoRESUMO
Seven cases of cystic neoplasms of the pancreas (5 cystadenomata and 2 cystadenocarcinomata) are reported. While cystadenomata were localized in the tail of pancreas, cystadenocarcinomata were localized in the head. Only one case was asymptomatic and evidenced in the course of other type of surgery. Preoperative diagnosis of cystadenoma was assessed only in one case. All benign forms were treated with radical resection. Only palliation was possible for malignant forms. The moderate malignancy of cystic tumors as compared to the more common pancreatic adenocarcinoma is underlined. A more careful intraoperative diagnosis and surgical resection are therefore advocated, whenever possible.
Assuntos
Cistadenocarcinoma/diagnóstico por imagem , Cistadenoma/diagnóstico por imagem , Neoplasias Pancreáticas/diagnóstico por imagem , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios XRESUMO
Duodenal leiomyosarcoma is a rare tumor and its current prognosis is poor. A case of duodenal leiomyosarcoma is described which recurred five years after the first intestinal resection, and was treated successfully with pancreaticoduodenectomy (PCD), extensive small bowel resection, and transverse, descending and sigmoid colon removal. The patient is still alive three years after this operation. Preservation of the stomach and the first duodenal portion after PCD most likely reduced the malabsorption, which is expected following such radical intestinal resection. This experience suggests an aggressive surgical approach to duodenal leiomyosarcomas, even when metastases are present.
Assuntos
Neoplasias Duodenais/cirurgia , Leiomiossarcoma/cirurgia , Ductos Biliares/cirurgia , Neoplasias do Colo/diagnóstico por imagem , Neoplasias do Colo/secundário , Neoplasias do Colo/cirurgia , Neoplasias Duodenais/diagnóstico por imagem , Humanos , Íleo/cirurgia , Jejuno/cirurgia , Leiomiossarcoma/diagnóstico por imagem , Leiomiossarcoma/secundário , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Pâncreas/cirurgia , Prognóstico , RadiografiaRESUMO
Administration of 1 mM dehydroascorbate (DHA) results in a rapid and large increase in cellular ascorbate (AA) content in both Lupinus albus L. and Allium cepa L. root tips. Uptake of DHA from the medium occurs at a high rate within 10-12 h of incubation, and is slowed down thereafter. In the first few h, DHA reduction to AA is apparently correlated to GSH depletion and slightly higher DHA reductase activity. DHA incubation also seems to induce new GSH synthesis. Longer DHA incubation (24 h) affects root growth by inhibiting cell proliferation. At this stage, an apparently generalised oxidation of SH-containing proteins is observed in DHA-treated roots. Treatment with 1 mM L-galactono-gamma-lactone, the last precursor of AA biosynthesis, results in an increase in AA content similar to that obtained with DHA, but stimulates growth and affects the redox state of SH-containing proteins in the opposite way. A possible multi-step mechanism of DHA reduction/removal is suggested and the hypothesis that DHA inhibits cell cycle progression by affecting the redox state of SH-containing proteins is discussed.
Assuntos
Ácido Desidroascórbico/farmacologia , Fabaceae/metabolismo , Cebolas/metabolismo , Raízes de Plantas/metabolismo , Plantas Medicinais , Divisão Celular , Fabaceae/efeitos dos fármacos , Fabaceae/crescimento & desenvolvimento , Dissulfeto de Glutationa/metabolismo , Glutationa Sintase/biossíntese , Meristema/metabolismo , Cebolas/efeitos dos fármacos , Cebolas/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Timidina/metabolismo , TrítioRESUMO
Leaves are specialized organs characterized by defined developmental destiny and determinate growth. The overexpression of Knotted1-like homeobox genes in different species has been shown to alter leaf shape and development, but a definite role for this class of genes remains to be established. Transgenics that overexpress Knotted1-like genes present some traits that are characteristic of altered cytokinin physiology. Here we show that lettuce (Lactuca sativa) leaves that overexpress KNAT1, an Arabidopsis kn1-like gene, acquire characteristics of indeterminate growth typical of the shoot and that this cell fate change is associated with the accumulation of specific types of cytokinins. The possibility that the phenotypic effects of KNAT1 overexpression may arise primarily from the modulation of local ratios of different cytokinins is discussed.
Assuntos
Proteínas de Arabidopsis , Citocininas/metabolismo , Proteínas de Homeodomínio/fisiologia , Lactuca/fisiologia , Proteínas de Plantas/fisiologia , Citocininas/genética , Citocininas/isolamento & purificação , Genes Homeobox , Proteínas de Homeodomínio/biossíntese , Proteínas de Homeodomínio/genética , Imuno-Histoquímica , Lactuca/citologia , Lactuca/genética , Lactuca/crescimento & desenvolvimento , Morfogênese , Fenótipo , Folhas de Planta/citologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , PlastocianinaRESUMO
The amount and spatial organization of the heterochromatin in nuclei of the shoot meristem and the frequency in the nuclear DNA of sequences belonging to a family of tandem repeats were investigated in cultivars of Olea europaea and related species. Significant differences between Olea species and between cultivars of O. europaea were observed: (i) in the spatial organization of the heterochromatin in interphase nuclei as determined by the number and surface area of the chromocentres; (ii) in genome size; and (iii) in the amount of condensed chromatin as measured by cytophotometry carried out at different thresholds of optical density. DNA elements belonging to a family of tandem repeats about 80 bp in length (OeTaq80 repeats) were isolated from the genomic DNA of an olive cultivar. It was shown: (i) by nucleotide sequence comparisons, that these repeats display variability in structure even within the same array, where different elements may share no more than 74% homology; (ii) by in situ hybridization, that OeTaq80-related DNA sequences are mainly localized in the heterochromatin at the chromosome ends; (iii) by dot-blot hybridization experiments, that these sequences are highly represented in the genome of all the olive cultivars and the majority of Olea species studied, and that their frequency may differ significantly even between olive cultivars; and (iv) by calculating the copy number of OeTaq80-related sequences per haploid (1C) genome, that the redundancy of these DNA elements may differ significantly between the genomes tested. It is suggested that the inter- and intraspecific changes in the nuclear and genomic traits observed can contribute to the understanding of the phylogenetic relationships between Olea species and in defining parameters to be exploited in varietal identification within cultivated olives.