RESUMO
We analyzed the pattern of spindle microtubule (MT) regrowth after cold- or colcemid-induced MT depolymerization in Drosophila S2 cells. Cold-induced MT disassembly at low temperature (2 °C) destroyed kinetochore-driven MT regrowth without affecting astral MT formation. Conversely, colcemid-induced MT depolymerization strongly impaired centrosome-dependent MT nucleation, allowing kinetochore-driven MT regrowth. Collectively, these results indicate that the kinetochore- and the centrosome-mediated MT assembly pathways exploit molecular mechanisms that are at least in part different.
Assuntos
Proteínas de Drosophila/metabolismo , Cinetocoros/metabolismo , Microtúbulos/metabolismo , Fuso Acromático/metabolismo , Tubulina (Proteína)/metabolismo , Animais , Linhagem Celular , Proteínas de Drosophila/genética , Drosophila melanogaster , Microtúbulos/genética , Fuso Acromático/genética , Tubulina (Proteína)/genéticaRESUMO
Genome size of Cyclops in cells at early stages of cleavage (up to the 5th division) and in somatic cells were estimated by a static digital Feulgen cytophotometry in order to study the quantitative changes in DNA content during chromatin diminution. Our realization of the cytophotometric method was approbeted on five different digital-imaging systems in blood cells of four vertebrate species. In all cases, we observed a direct correlation of the obtained and known from the literature data on the genome size and a high reproducibility, which allows to use these systems in future work. We also optimized the conditions for DNA hydrolysis of both blood smears, and for two species of Cyclops from the Moscow population, as 30 min in 5 N HCl at 24 degrees C. Here we first revealed chromatin diminution in two endemic Baikal species of Cyclopoida: Acanthocyclops incolotaenia and Diacyclops galbinus estimated the extent ofchromatin diminution in Diacyclops galbinus as 95.5-96.2 %. Cytometric analysis of the third species, Mesocyclops leuckarti, did not reveal obvious chromatin diminution. We also optimized the conditions for DNA hydrolysis of both blood smear preparations, and for two species of copepods from the Moscow population, as 30 min in 5N HCl at 24 degrees C.
Assuntos
Copépodes/citologia , Copépodes/metabolismo , Citofotometria/métodos , DNA/metabolismo , Genoma/fisiologia , Animais , Copépodes/genética , DNA/genética , SibériaRESUMO
Chromatin diminution (CD) in two Cyclopoida species, Cyclops kolensis and C. insignis, was studied by static digital Feulgen cytophotometry. DNA content (pg/cell) was evaluated by standard curves builded up using blood cells of five organisms with known DNA content, which ranged from 1.25 to 14.70 pg. According to data obtained, diploid genome of C. kolensis has about 40 pg DNA before CD and 1.8-2.0 pg DNA after CD. These values are similar for both Moscow and Baikal populations of C. kolensis and 6-10 times exceed estimates made earlier (Grishanin, 2008), Our data confirm that CD in C. kolensis is 94-96% of DNA. In mitotic dividing cells of C. insignis, DNA content was about 7.5 pg both in early and late embryos, and CD was not revealed for this species. The data obtained show that, among Cyclopoida studied, the genome of C. kolensis before CD has a maximum content of DNA.
Assuntos
Núcleo Celular/ultraestrutura , Cromatina/genética , Copépodes/ultraestrutura , DNA/metabolismo , Animais , Núcleo Celular/genética , Copépodes/genética , Copépodes/crescimento & desenvolvimento , Citofotometria , Feminino , Especificidade da EspécieRESUMO
Quantitative nuclei DNA content measurement based on Feulgen reaction and the analysis of CCD images was tested. The measurements were performed in monochorome CCD option (650 X 514 pixels) with the wavelength 551 nm. The linear dependence of photomatrix elements signals on the falling light was shown with the use of multigraded light absorption filter. The optimal microscope and camera setting and an approach for elimination of the optic blur were found. We have shown that the proper Feulgen fluorescence does not affect our measurements. Densitometric DNA content measurements of blood cells of four vertebrate species (Gallus domesticus, Danio rerio, Homo sapiens and Rana arvalis) showed good consistence to the literature data (http://www.genomesize.com). The precision of our approach is comparable to the other known methods. Current improvement of CCD technical parameters and wide usage of CCD cameras in biological applications gives perspectives for the suggested approach.
Assuntos
Citofotometria/métodos , DNA/análise , Animais , Células Sanguíneas/química , Núcleo Celular/química , Citofotometria/instrumentação , Densitometria , Humanos , Fotografação , Corantes de Rosanilina/química , Sensibilidade e EspecificidadeRESUMO
Cystic adenomatoid malformations of the lung belong to a group of abnormalities, the only treatment is surgery. This raises the question as to the earliest detection of this lung abnormality in children. Up to the present, there have been cases of late diagnosis of this abnormality masked by an inflammatory process in the lung, its abscess, and even tuberculosis lesion of lung tissue. We describe a case of cystic adenomatoid malformation of the lung in a child, by discussing the capabilities of chest computed tomography in the diagnosis of lung malformations in children. When inflammatory lung changes are found in children, it is necessary to keep in mind that these alterations may develop in the presence of the malformation. To clarify the pattern of the disease, by applying current radiodiagnostic techniques, allows the choice of optimal treatment policy and the time and volume of surgical intervention.