The mitotic spindle is a self-organized micro-machine composed of microtubules and associated proteins, which divides genetic material between its two nascent daughter cells. Forces exist in the spindle throughout mitosis and are crucial for spindle functioning in each phase. In metaphase, the mitotic spindle has a recognizable shape with a characteristic arrangement of microtubules....
Chromosome positioning to the equatorial plane of the mitotic spindle is necessary to prevent lagging chromosomes and abnormal nuclear envelope reformation [1,2]. It has been proposed that two centering mechanisms play a key role here, microtubule (MT) catastrophe promoted by kinesin-8 motors and pushing forces exerted by chromokinesins. Surprisingly, our experiments suggest that removal of...
Cells need to be positioned correctly during embryogenesis for achieving important processes like body axis formation and organ development. The mechanisms by which cells reposition in the early developing embryo are still not completely understood. Recently, Naganathan et al 2014, showed that the gradient of myosin in the actomyosin cortex generates chiral flows and these flows are important...
Chromosome segregation errors cause aneuploidy, a state of numerical alterations in chromosomes that contributes to tumor initiation and progression. Improper attachments between chromosomes and microtubules are the most common mechanism causing chromosome mis-segregation [1]. However, frequency and identity of error mechanisms have not been studied extensively. Here, we quantitatively...
The spindle during metaphase consists of evenly distributed and well-organized microtubule bundles. It is unknown how this recognizable architecture arises during prometaphase. Here we show that during prometaphase the spindle contains antiparallel PRC1 labelled bundles the number of which increases in time by longitudinal splitting of preexisting bundles and by de novo assembly. By using live...
There is increasing evidence that fairness and generosity are not exclusive human traits.
Indeed, several experiments on chimpanzees, monkeys and other mammals show an inequity-aversion behavior.
Namely, if some valuable resource, e.g. food, is unevenly divided between two individuals, the one who gets a smaller share may reject the reward, and, in some cases, there can even be an attempt of...
In many biological systems the individual agents cluster together in space and exhibit collective behavior [1]. Thousands of starling birds show spectacular collective aerial maneuvers near their home, migratory birds migrate as a flock, school of fish forage together, thousands of insects march and feast on the crop fields etc are few examples[2-4].
Many simulation models are proposed to...
During mitosis, microtubules form a spindle, which is responsible for the segregation of chromosomes. In yeast cells, the spindle has a rod-like structure and is made of microtubules emanating from two poles connected by cross-linking proteins. Microtubules self-organize into parallel or antiparallel bundles, depending on whether they grow from the same or two different poles and our goal here...
Cytokinesis is a fundamental step of cell division. This event results in the assembly of circumferential actomyosin-based contractile ring at the equatorial cortex of the cell. The contractile ring is positioned properly by the spatiotemporal cues from the mitotic spindle to the cortex. Experiments have revealed that the localization of myosin in the contractile ring is controlled via the...
The statistics of first passage times (FPT) is used widely in the field of statistical physics. In this work, we study the FPT distributions of water near three different crystal surfaces of the amino acid glutamine. We show that each surface leaves a unique fingerprint of the structural and geometrical properties of crystal in the FPT distributions. We also establish a...
The nature of forces driving chromosome segregation in human mitotic spindle remains one of the most challenging questions in the field. Although different microtubule populations have been well characterized in anaphase, their contribution to segregation remains unclear. Recently, it was shown that antiparallel interpolar microtubules in central spindle are strongly crosslinked with...
Chromosome segregation during cell division is carefully choreographed to ensure equal partitioning of the duplicated genetic material. If this process fails to occur accurately, the resulting daughters might have karyotype imbalance, known as aneuploidy. Even though mitotic errors have been studied extensively, the mechanisms generating various errors, their propagation and effects on genome...
Biophysics is a growing field that involves mathematical modelling and data analysis to study biological, medical and ecological processes. In this presentation we show two applications of stochastic resetting to understand drug resistance development and RNA transcription.
Drug resistance development is the process in which the current therapy against an infection is decreased in...
