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Herbs in Cancer Therapy
Published in Anil K. Sharma, Raj K. Keservani, Surya Prakash Gautam, Herbal Product Development, 2020
Annum Malik, Shahzadi Sidra Saleem, Kifayat Ullah Shah, Learn-Han Lee, Bey Hing Goh, Tahir Mehmood Khan
Two important classes of the tubulin-binding agents include Vinca alkaloids and taxanes. Vinca alkaloids are microtubule-targeting drugs which binds with ɑ/β-tubulin dimers and as a result destabilized the microtubules. (Hassan and MA). Recent evidence indicates that microtubule function is disrupted by both kinds of drugs including taxanes that are known to be microtubule stabilizing drugs and vinca alkaloids that are considered as microtubule destabilizing drugs (Escuin et al. 2005). Hence, they prevent the proper alignment of daughter chromosomes to the microtubules. This disruption in proper alignment of daughter chromosomes on microtubules results in the inhibition of phases of mitotic cell division, particularly metaphase and anaphase. Such inhibition of cell division or particularly called cell cycle arrest may ultimately be followed by apoptosis (Nobili et al. 2009). For example, vinca alkaloids prevents cell cycle progression and induce mitotic block and apoptosis. Whatever the concentration of vinca alkaloids, mitochondria appear to be at the point of convergence for the apoptotic signals (Pourroy et al. 2004). Podophyllotoxin binds to microtubules, thus preventing their formation and destabilizing them (Darwiche et al. 2007).
Basic Cell Biology
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
In mitosis, each chromosome duplicates itself. The duplicated strands separate as the nucleus divides, so that the daughter nuclei have the same set of chromosomes as their parent cell. Figure 2.2 shows a diagrammatic representation of the process of mitosis in a cell. During mitosis, a cell passes through four stages: prophase, metaphase, anaphase, and telophase. During prophase, each chromosome doubles itself, and the nuclear membrane and nucleus disappear. During metaphase, spindles form and chromosomes lie on the equatorial plate. During anaphase, chromosomes separate, and each half moves toward a pole. During telophase, the nucleus appears, and the cell divides into two daughter cells — each having an identical set of diploid chromosomes. The process of mitosis is so precise that any change in the chromosomes or DNA would definitely reflect in daughter cells after completion of cell division.
Chromosome Pairing and Fertility in Plant Hybrids
Published in Christopher B. Gillies, Fertility and Chromosome Pairing: Recent Studies in Plants and Animals, 2020
The fertility of a hybrid may also be reduced by irregularities in meiosis of germ line cells. Conventional light microscopy may reveal that chromosomes pair regularly during meiotic prophase, but fail to form chiasmata due to problems of homology arising from structural or numerical rearrangements of the genome, or to impairment of the mechanism of chiasma formation due to genic imbalance resulting from hybridity. The inevitable consequences are that the chromosomes desynapse and disjoin irregularly at anaphase I. The capacity of nonhomologous or homoeologous chromosomes to form chiasmata can be used to some advantage in gauging the relatedness of the genomes of the hybrid from an evolutionary point of view. In other words, the more regular the chiasmate association of chromosomes at metaphase I, the more closely related the chromosomes are likely to be from a genetic or structural viewpoint. Indeed, it is cytological observations of this nature which have helped cytogeneticists unravel the evolution of natural allopolyploids, such as wheat and tobacco, which contain a combination of distinct but similar genomes.
Bioinformatic analysis of the clinicopathological and prognostic significance of oocyte-arresting BTG4 mRNA expression in gynecological cancers
Published in Journal of Obstetrics and Gynaecology, 2023
Hua-chuan Zheng, Hang Xue, Cong-yu Zhang, Rui Zhang
Räty et al. (2011) identified BTG4 as a potential candidate for oocyte developmental competence, as a secreted acidic protein rich in cysteine for cumulus cell expansion. Moreover, Liu et al. (2021) reported that a novel homozygous missense variant in BTG4 causes zygotic cleavage failure and female infertility. Meanwhile, Chu et al. (2012) found that BTG4 had a higher mRNA level in oocytes treated with FSH than in those produced through the natural cycle. Furthermore, Pasternak et al. (2016) demonstrated that the BTG4-CAF1 complex safeguarded metaphase II arrest in mammalian eggs by deadenylating maternal mRNAs. BTG4-depleted eggs progressed into anaphase II spontaneously before fertilization. BTG4 prevented the progression into anaphase by ensuring that the anaphase-promoting complex/cyclosome (APC/C) was completely inhibited during the arrest. These findings indicate that BTG4 may block the cycle progression of oocytes or eggs.
Epigenetic factors of individual radiosensitivity and adaptive capacity
Published in International Journal of Radiation Biology, 2020
Alexandra P. Kravets, Daryna A. Sokolova
Apical root meristem was used for cytogenetic assay. Samples for cytogenetic assay were collected on the fourth day after irradiation. After separation from the roots, the apexes were placed in a Brodsky fixation solution (0.3 acetic acid: 1 ethanol: 3 formaldehyde mixture) for 2 h and then washed with ethanol 3–4 times. Maceration was performed by alkaline hydrolysis with 20% NaOH for 2 h. After that, the preparations were washed with distilled water for 15 min. Staining was performed with a mixture of acetoorcein and hydrochloric acid (1 acetoorcein: acetoorcein: 1 1 M HCl) for 16–18 h. The stained material was washed with 45% CH3COOH and squash preparations were prepared. To perform an analysis, ten parallel samples were prepared and 5000–10,000 cells were analyzed. An analysis of chromosome aberrations was performed by the anaphase – telophase method, taking into account the specificity of plant tissues. The anaphase cell samples were at least 300–500 cells per each preparation.
Effect of electromagnetic field exposure on the transcription of repetitive DNA elements in human cells
Published in Electromagnetic Biology and Medicine, 2019
Brunella Del Re, Ferdinando Bersani, Gianfranco Giorgi
Here we reported mRNA level changes but we do not know whether this biological effect is enduring or transient, what these changes mean and whether they can affect cell functionality. The increase of RE-DNA mRNA induced by RF-EMF exposure could result in cellular dysfunction. Indeed, L1 transcription increase is observed in cancer cells and has been considered to play a role in tumorigenesis and/or tumour progression (reviewed by Burns 2017). Increased transcriptional activity of HERV-H sequences has been found in different types of cancer and in several neurological and psychiatric diseases (Balestrieri et al. 2014; Cipriani et al. 2018) suggesting that HERV-H transcription could take part in many multifactorial complex diseases. SAT DNA aberrant transcription was found in several tumor types suggesting that altered transcription levels are detrimental and may play a role in tumorigenesis or cancer progression (Ferreira et al. 2015), causing a chromosome missegregation in anaphase and aneuploidy.