Cytokinesis

Summary Primary cilia, which emanate from the cell surface, exhibit assembly and disassembly dynamics along the progression of cell cycle. However, the mechanism that links ciliary dynamics and cell cycle regulation remains elusive. Here, we report that Polo-like kinase 1 (Plk1), one of the key cell cycle regulators, which regulate centrosome maturation, bipolar spindle assembly and cytokinesis, acts as a pivotal player that connects the ciliary dynamics and cell cycle regulation. We found that the kinase activity of ...

Fowl Adeno Viruses (FAdVs) are non-enveloped and double-stranded DNA viruses. They include eight species (FAdVs A-E) and 12 serotypes (FAdVs-1 to-8a and-8b to-11). Strains of FAdVs have been widely distributed in different countries all over the world. Most avian species are susceptible to FAdVs infections. Vertical, horizontal, and mechanical infections and transmissions have been recorded in different forms of FAdVs infection. There are many forms of FAdVs infections according to the groups (including three groups) of the virus. Group 1 usually causes inclusion body hepatitis, hydropericardium syndrome, quail bronchitis, pancreatic erosions, gizzard erosion, cardiovascular, hematopoietic, and respiratory systems disorders. Group II is incriminated in diseases, such as turkey hemorrhagic enteritis, marble spleen disease in pheasants, and splenomegaly in chickens. In addition, group III is responsible for egg drop syndrome in laying chickens. Diagnosis of FAdVs infections is not based on the signs and lesions. However, microscopic detection of specific lesions and inclusion bodies may be suggestive. Diagnosis is mainly based on the conventional traditional isolation in embryonated eggs of different avian species as well as on tissue culture of avian origin. Molecular diagnostic techniques are now widely used for rapid and confirmative detection of FAdVs. The application of sanitary and hygienic measures in poultry farms is very important to prevent FAdVs outbreaks. However, different types of inactivated, living attenuated as well as recombinant vaccines have been developed and used in several countries to overcome different forms of FAdVs. Therefore, this review article deals with the FAdVs susceptibility and transmission, the etiological agent, forms of infections, and diagnosis as well as different methods of prevention and control.

Dental Irregularities are frequently related with orthodontic problems. It may include
variations in the number of teeth, size of teeth (Macro and Micro Dontia) or pattern of
eruption. Such anomalies may lead to disturbances in the arch length of maxilla and
mandible as well as occlusion. Sometimes they are associated with different syndromes. The
prevalence of such abnormalities is diverse in different societies and races of the world. In
fact, there was a significant change amongst genders of the same society. In Pakistan, the
prevalence of hypodontia, hyperdontia and impactions are found to be 3.38%, 0.95% and
8.57 respectively.

Cryptococcus neoformans is an encapsulated yeast belongs to basidiomycetes, causing morbidity and mortality in specialized populations such as HIV/AIDS. It is related to the immune system of the host, both, cellular and humoral immunity. Furthermore, intact and adequate immune system is needed in order to prevent and control infection. Mononuclear phagocytic cells (monocyte and macrophage) plays a central role in protective immunity against this intracellular microorganism. Normal macrophage have the ability to phagocyte and destroy internalized pathogen, through the action of lysosomal enzymes. In HIV infected individuals, even though internalization still occur but instead of being destroyed, the yeast can reside and replicate inside the phagolysosome compartment, a process known as intracellular parasitism. During that process, internalized yeast cells can undergo lateral transfer from infected macrophages to non-infected ones. This process allows dissemination of the fungus to other part of the body.

Cerebral cavernous malformations (CCMs) are vascular defects of the CNS that arise from loss of integrity of the endothelial cells lining blood capillaries, causing leakage of blood into the brain [1]. This results in headaches, seizures, and/or hemorrhagic stroke, depending on the location of the lesion. CCM affects 0.5% of the population and follows an autosomal dominant inheritance pattern caused by mutations in one of the three genes: CCM1 (gene name KRIT1), CCM2 (also known as malcavernin or OSM), and CCM3 (gene name PDCD10) [2, 3], with the earliest onset and most severe prognosis occurring in CCM3 patients [4]. The three CCM genes encode structurally distinct scaffold proteins that function in multiple complexes [5–9]. Using the C. elegans germline as a model of multicellular tube development, we show here that CCM-3 is enriched at the luminal membrane of the germline and the contractile ring of dividing cells in the embryo. Loss of ccm-3 results in defective RAB-11-mediated endocytic recycling, which in turn is necessary for gonadal lumen (rachis) formation, completion of cytokinesis, and localization of cell-surface receptors. CCM-3-mediated localization of anillin and non-muscle myosin to the lateral surfaces of germ cells is required for proper cytoskeletal organization, subsequent oocyte growth, and localization of polarity proteins. Biochemical analysis reveals conservation of the STRIPAK complex and distinct roles for GCK-1 (germinal center kinase III family protein) and striatin/CASH-1 in controlling the localization and function of CCM-3. Taken together, our data establish CCM-3 as a novel regulator of rachis lumenization and polarity establishment during embryogenesis.

Exposure to ozone in air pollution in urban environments is associated with increases in pulmonary-related hospitalizations and mortality. Because ozone also alters clearance of pulmonary bacterial pathogens, we hypothesized that inhalation of ozone modifies innate immunity in the lung. To address our hypothesis, we exposed C57BL/6J mice to either free air or ozone, and then subsequently challenged with an aerosol

YAP is a transcriptional coactivator that controls organ expansion and differentiation and is inhibited by the Hippo pathway in cells in interphase. Here, we demonstrated that, during mitosis, YAP localized to the midbody and spindle, subcellular structures that are involved in cytokinesis, the process by which contraction of the cytoskeleton produces two daughter cells. Furthermore, YAP was phosphorylated by CDK1, a kinase that promotes cell cycle progression. Knockdown of YAP by shRNA or expression of a nonphosphorylatable form of YAP delayed the separation of daughter cells (called abscission) and induced a cytokinesis phenotype associated with increased contractile force, membrane blebbing and bulges, and abnormal spindle orientation. Consequently, these defects led to an increased frequency of multinucleation, micronuclei, and aneuploidy. YAP was required for proper localization of proteins that regulate contraction during cytokinesis, including ECT2, MgcRacGap, Anillin, and RH...

The adult mammalian heart is incapable of meaningful regeneration after substantial cardiomyocyte loss, primarily due to the inability of adult cardiomyocytes to divide. Our group recently showed that mitochondria-mediated oxidative DNA damage is an important regulator of postnatal cardiomyocyte cell cycle arrest. However, it is not known whether mechanical load also plays a role in this process. We reasoned that the postnatal physiological increase in mechanical load contributes to the increase in mitochondrial content, with subsequent activation of DNA damage response (DDR) and permanent cell cycle arrest of cardiomyocytes. The purpose of this study was to test the effect of mechanical unloading on mitochondrial mass, DDR, and cardiomyocyte proliferation. We examined the effect of human ventricular unloading after implantation of left ventricular assist devices (LVADs) on mitochondrial content, DDR, and cardiomyocyte proliferation in 10 matched left ventricular samples collected a...

Standard cytogenetic assays used in genotoxicology usually include chromosome aberrations analysis and micronucleus cytokinesis-block assay. Both tests originate on standard protocol for lymphocyte culture and can be used as complement or substitute to each other. Aim of this study was to evaluate complementarities between results of chromosome aberration analysis assay and results of micronucleus cytokinesis-block assay in representative sample of inhabitants from Bosnia and Herzegovina. The aim was achieved by calculating Pearson correlation coefficient and simple linear regression.

Controlling microtubule dynamics and spatial organization is a fundamental requirement of eukaryotic cell function. Members of the ORBIT/MAST/CLASP family of microtubule-associated proteins associate with the plus ends of microtubules, where they promote the addition of tubulin subunits into attached kinetochore fibers during mitosis and stabilize microtubules in the vicinity of the plasma membrane during interphase. To date, nothing is known about their function in plants. Here, we show that the Arabidopsis thaliana CLASP protein is a microtubule-associated protein that is involved in both cell division and cell expansion. Green fluorescent protein–CLASP localizes along the full length of microtubules and shows enrichment at growing plus ends. Our analysis suggests that CLASP promotes microtubule stability. clasp-1 T-DNA insertion mutants are hypersensitive to microtubule-destabilizing drugs and exhibit more sparsely populated, yet well ordered, root cortical microtubule arrays. Ov...

The use of biomarkers of early genetic effects, predictive for cancer, such as micronuclei (MN) in lymphocytes, may help to investigate the association between diet and cancer. We hypothesised that the presence of mutagens in the diet may increase MN formation. A 'pooled' standardised analysis was performed by applying the same experimental protocol for the cytokinesis block micronucleus assay in 625 young healthy women after delivery from five European study populations (Greece, Denmark, UK, Spain and Norway). We assessed MN frequencies in mono- and binucleated T-lymphocytes (MNMONO and MNBN) and the cytokinesis blocked proliferation index using a semi-automated image analysis system. Food frequency questionnaires (FFQs) were used to estimate intake of fatty acids and a broad range of immunotoxic and genotoxic/carcinogenic compounds through the diet. Pooled difference based on delivery type revealed higher MNMONO frequencies in caesarean than in vaginal delivery (P = 0.002)...

Very little is known about growth and proliferation in relation to the cell cycle regulation of algae. The lack of knowledge is even greater when referring to the potential toxic effects of pollutants on microalgal cell division. To assess the effect of terbutryn, a triazine herbicide, on the proliferation of the freshwater microalga Chlorella vulgaris three flow cytometric approaches were used: (1) in vivo cell division using 5-,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) staining was measured, (2) the growth kinetics were determined by cytometric cell counting and (3) cell viability was evaluated with the membrane-impermeable double-stranded nucleic acid stain propidium iodide (PI).The results obtained in the growth kinetics study using CFSE to identify the microalgal cell progeny were consistent with those determined by cytometric cell counting. In all C. vulgaris cultures, each mother cell had undergone only one round of division through the 96 h of assay and the cell division occurred during the dark period. Cell division of the cultures exposed to the herbicide was asynchronous. Terbutryn altered the normal number of daughter cells (4 autospores) obtained from each mother cell. The number was only two in the cultures treated with 250 nM. The duration of the lag phase after the exposure to terbutryn could be dependent on the existence of a critical cell size to activate cytoplasmic division. Cell size, complexity and fluorescence of chlorophyll a of the microalgal cells presented a marked light/dark (day/night) cycle, except in the non-dividing 500 nM cultures, where terbutryn arrested cell division at the beginning of the cycle. Viability results showed that terbutryn has an algastatic effect in C. vulgaris cells at this concentration.The rapid and precise determination of cell proliferation by CFSE staining has allowed us to develop a model for assessing both the cell cycle of C. vulgaris and the in vivo effects of pollutants on growth and reproduction at microalgal cell level.