Requirements for contractility in disordered cytoskeletal bundles

Actomyosin contractility is essential for biological force generation, and is well understood in highly organized structures such as striated muscle. Additionally, actomyosin bundles devoid of this organization are known to contract both in vivo and in vitro, which cannot be described by standard muscle models. To narrow down the search for possible contraction mechanisms in these systems, we investigate their microscopic symmetries. We show that contractile behavior requires non-identical motors that generate large enough forces to probe the nonlinear elastic behavior of F-actin. This suggests a role for filament buckling in the contraction of these bundles, consistent with recent experimental results on reconstituted actomyosin bundles.Comment: 10 pages, 6 figures; text shortene

Logical gates in actin monomer

© 2017 The Author(s). We evaluate information processing capacity of a single actin molecule by calculating distributions of logical gates implemented by the molecule via propagating patterns of excitation. We represent a filamentous actin molecule as an excitable automaton network (F-actin automaton). where every atom updates its state depending on states of atoms its connected to with chemical bonds (hard neighbours) and atoms being in physical proximity to the atom (soft neighbours). A resting atom excites if a sum of its excited hard neighbours and a weighted sum of its soft neighbours belong to some specified interval. We demonstrate that F-actin automata implement OR, AND, XOR and AND-NOT gates via interacting patterns of excitation. Gate AND is the most common gate and gate XOR is the rarest. Using the architectures of gates discovered we implement one bit half-adder and controlled-not circuits in the F-actin automata. Speed and space values of the F-actin molecular computers are discussed

Vitamin C and infectious diseases

Non peer reviewe

Information storing by biomagnetites

Since the discovery of the presence of biogenic magnetites in living organisms, there have been speculations on the role that these biomagnetites play in cellular processes. It seems that the formation of biomagnetite crystals is a universal phenomenon and not an exception in living cells. Many experimental facts show that features of organic and inorganic processes could be indistinguishable at nanoscale levels. Living cells are quantum "devices" rather than simple electronic devices utilizing only the charge of conduction electrons. In our opinion, due to their unusual biophysical properties, special biomagnetites must have a biological function in living cells in general and in the brain in particular. In this paper we advance a hypothesis that while biomagnetites are developed jointly with organic molecules and cellular electromagnetic fields in cells, they can record information about the Earth's magnetic vector potential of the entire flight in migratory birds.Comment: 17 pages, 3 figure

From conformons to human brains: an informal overview of nonlinear dynamics and its applications in biomedicine

Methods of contemporary physics are increasingly important for biomedical research but, for a multitude of diverse reasons, most practitioners of biomedicine lack access to a comprehensive knowledge of these modern methodologies. This paper is an attempt to describe nonlinear dynamics and its methods in a way that could be read and understood by biomedical professionals who usually are not trained in advanced mathematics. After an overview of basic concepts and vocabulary of nonlinear dynamics, deterministic chaos, and fractals, application of nonlinear methods of biosignal analysis is discussed. In particular, five case studies are presented: 1. Monitoring the depth of anaesthesia and of sedation; 2. Bright Light Therapy and Seasonal Affective Disorder; 3. Analysis of posturographic signals; 4. Evoked EEG and photo-stimulation; 5. Influence of electromagnetic fields generated by cellular phones

Fermented wheat germ extract - nutritional supplement or anticancer drug?

<p>Abstract</p> <p>Background</p> <p>Fermented wheat germ extract (FWGE) is a multisubstance composition and, besides others, contains 2-methoxy benzoquinone and 2, 6-dimethoxy benzoquinone which are likely to exert some of its biological effects. FWGE interferes with anaerobic glycolysis, pentose cycle and ribonucleotide reductase. It has significant antiproliferative effects and kills tumor cells by the induction of apoptosis via the caspase-poly [ADP-ribose] polymerase-pathway. FWGE interacts synergistically with a variety of different anticancer drugs and exerted antimetastatic properties in mouse models. In addition, FWGE modulates immune response by downregulation of MHC-I complex and the induction of TNF-α and various interleukins. Data in the F-344 rat model provide evidence for a colon cancer preventing effect of FWGE.</p> <p>Clinical data from a randomized phase II trial in melanoma patients indicate a significant benefit for patients treated with dacarbazine in combination with FWGE in terms of progression free survival (PFS) and overall survival (OS). Similarly, data from studies in colorectal cancer suggested a benefit of FWGE treatment. Besides extension of OS and PFS, FWGE improved the quality of life in several studies.</p> <p>Conclusion</p> <p>In conclusion, available data so far, justify the use of FWGE as a non-prescription medical nutriment for cancer patients. Further randomized, controlled and large scale clinical studies are mandatory, to further clarify the value of FWGE as a drug component of future chemotherapy regimens.</p

The Fundamental Biological Activity of the Universe

If everything is in permanent change, can the Universe itself be fundamentally passive? Answering this question requires a clear concept of ‘activity.’ The nature of ‘action’ is a central and unsolved philosophical problem. Actions play a crucial role in the way we conceive of ourselves, life and the Universe, and the value we put on these. In four decades of research on solar activity, we found that activity is not a mere occurrence but a genuine activity of the Sun, initiated globally by the Sun using quantum processes as tools that generates suitable primary mass flows locally in the solar core that are capable of producing a working dynamo. We argue that solar activity is initiated by biological causes given by the fundamental principle of biology. This universal activity is the basis of our life instinct and of logic too