Molecular Codes Through Complex Formation in a Model of the Human Inner Kinetochore

We apply molecular code theory to a rule-based model of the human inner kinetochore and study how complex formation in general can give rise to molecular codes. We analyze 105 reaction networks generated from the rule-based inner kinetochore model in two variants: with and without dissociation of complexes. Interestingly, we found codes only when some but not all complexes are allowed to dissociate. We show that this is due to the fact that in the kinetochore model proteins can only bind at kinetochores by attaching to already attached proteins and cannot form complexes in free solution. Using a generalized linear mixed model we study which centromere protein (CENP) can take which role in a molecular code (sign, meaning, context). By this, associations between CENPs (CenpA, CenpQ, CenpU and CenpI) and code roles are found. We observed that CenpA is a major risk factor (increases probability for code role) while CenpQ is a major protection factor (decreases probability for code role). Finally we show, using an abstract model of copolymer formation, that molecular codes can also be realized solely by the formation of stable complexes, which do not dissociate. For example, with particular dimers as context a molecular code mapping from two different monomers to two particular trimers can be realized just by non-selective complex formation. We conclude that the formation of protein complexes can be utilized by the cell to implement molecular codes. Living cells thus facilitate a subsystem allowing for an enormous flexibility in the realization of mappings, which can be used for specific regulatory processes, e.g. via the context of a mapping.     

Rescue of nonsense mutations by amlexanox in human cells

ABSTRACT: BACKGROUND: Nonsense mutations are at the origin of many cancers and inherited genetic diseases. The consequence of nonsense mutations is often the absence of mutant gene expression due to the activation of an mRNA surveillance mechanism called nonsense-mediated mRNA decay (NMD). Strategies to rescue the expression of nonsense-containing mRNAs have been developed such as NMD inhibition or nonsense mutation readthrough. METHODS: Using a dedicated screening system, we sought molecules capable to block NMD. Additionally, 3 cell lines derived from patient cells and harboring a nonsense mutation were used to study the effect of the selected molecule on the level of nonsense-containing mRNAs and the synthesis of proteins from these mutant mRNAs. RESULTS: We demonstrate here that amlexanox, a drug used for decades, not only induces an increase in nonsense-containing mRNAs amount in treated cells, but also leads to the synthesis of the full-length protein in an efficient manner. We also demonstrated that these full length proteins are functional. CONCLUSIONS: As a result of this dual activity, amlexanox may be useful as a therapeutic approach for diseases caused by nonsense mutations.     

Comparative assessment of passive surveillance in disease-free and endemic situation: Example of <Emphasis Type="Italic">Brucella melitensis</Emphasis> surveillance in Switzerland and in Bosnia and Herzegovina

Background

Globalization and subsequent growth in international trade in animals and animal products has increased the importance of international disease reporting. Efficient and reliable surveillance systems are needed in order to document the disease status of a population at a given time. In this context, passive surveillance plays an important role in early warning systems. However, it is not yet routinely integrated in the assessment of disease surveillance systems because different factors like the disease awareness (DA) of people reporting suspect cases influence the detection performance of passive surveillance. In this paper, we used scenario tree methodology in order to evaluate and compare the quality and benefit of abortion testing (ABT) for Brucella melitensis (Bm) between the disease free situation in Switzerland (CH) and a hypothetical disease free situation in Bosnia and Herzegovina (BH), taking into account DA levels assumed for the current endemic situation in BH.

Results

The structure and input parameters of the scenario tree were identical for CH and BH with the exception of population data in small ruminants and the DA in farmers and veterinarians. The sensitivity analysis of the stochastic scenario tree model showed that the small ruminant population structure and the DA of farmers were important influential parameters with regard to the unit sensitivity of ABT in both CH and BH. The DA of both farmers and veterinarians was assumed to be higher in BH than in CH due to the current endemic situation in BH. Although the same DA cannot necessarily be assumed for the modelled hypothetical disease free situation as for the actual endemic situation, it shows the importance of the higher vigilance of people reporting suspect cases on the probability that an average unit processed in the ABT-component would test positive.

Conclusion

The actual sensitivity of passive surveillance approaches heavily depends on the context in which they are applied. Scenario tree modelling allows for the evaluation of such passive surveillance system components under assumed disease free situation. Despite data gaps, this is a real opportunity to compare different situations and to explore consequences of changes that could be made.

     

Body dysmorphic disorder: diagnosis and approach

Body dysmorphic disorder is a psychiatric disease that can be frequently encountered in an aesthetic practice. Body dysmorphic disorder is characterized by a preoccupation with a minimal or nonexistent appearance defect and causes significant distress and interferes with the social life of the patient. The perceived physical anomaly may involve the shape and size of the whole body or may be centered around single units. Body dysmorphic disorder patients are known to request multiple aesthetic procedures that leave them unsatisfied. Only a timely diagnosis will enable the surgeon and staff to adequately address the patient's needs. Body dysmorphic disorder patients cannot be cured with surgery. Diagnostic techniques such as patient interview and observation are presented in this article. With this, the plastic surgeon should be able to diagnose body dysmorphic disorder preoperatively. Using the presented algorithm to approach body dysmorphic disorder patients will avoid disappointment for patients and surgeons alike.     

Differential impact of simultaneous migration on coevolving hosts and parasites

Background  

The dynamics of antagonistic host-parasite coevolution are believed to be crucially dependent on the rate of migration between populations. We addressed how the rate of simultaneous migration of host and parasite affected resistance and infectivity evolution of coevolving meta-populations of the bacterium Pseudomonas fluorescens and a viral parasite (bacteriophage). The increase in genetic variation resulting from small amounts of migration is expected to increase rates of adaptation of both host and parasite. However, previous studies suggest phages should benefit more from migration than bacteria; because in the absence of migration, phages are more genetically limited and have a lower evolutionary potential compared to the bacteria.     

A versatile approach to multiple gene RNA interference using microRNA-based short hairpin RNAs

Background  

Effective and stable knockdown of multiple gene targets by RNA interference is often necessary to overcome isoform redundancy, but it remains a technical challenge when working with intractable cell systems.     

Comparison of different delivery systems of DNA vaccination for the induction of protection against tuberculosis in mice and guinea pigs

The great challenges for researchers working in the field of vaccinology are optimizing DNA vaccines for use in humans or large animals and creating effective single-dose vaccines using appropriated controlled delivery systems. Plasmid DNA encoding the heat-shock protein 65 (hsp65) (DNAhsp65) has been shown to induce protective and therapeutic immune responses in a murine model of tuberculosis (TB). Despite the success of naked DNAhsp65-based vaccine to protect mice against TB, it requires multiple doses of high amounts of DNA for effective immunization. In order to optimize this DNA vaccine and simplify the vaccination schedule, we coencapsulated DNAhsp65 and the adjuvant trehalose dimycolate (TDM) into biodegradable poly (DL-lactide-co-glycolide) (PLGA) microspheres for a single dose administration. Moreover, a single-shot prime-boost vaccine formulation based on a mixture of two different PLGA microspheres, presenting faster and slower release of, respectively, DNAhsp65 and the recombinant hsp65 protein was also developed. These formulations were tested in mice as well as in guinea pigs by comparison with the efficacy and toxicity induced by the naked DNA preparation or BCG. The single-shot prime-boost formulation clearly presented good efficacy and diminished lung pathology in both mice and guinea pigs.