14 research outputs found
Modeling the asymmetric evolution of a mouse and rat-specific microRNA gene cluster intron 10 of the Sfmbt2 gene
<p>Abstract</p> <p>Background</p> <p>The total number of miRNA genes in a genome, expression of which is responsible for the miRNA repertoire of an organism, is not precisely known. Moreover, the question of how new miRNA genes arise during evolution is incompletely understood. Recent data in humans and opossum indicate that retrotranspons of the class of short interspersed nuclear elements have contributed to the growth of microRNA gene clusters.</p> <p>Method</p> <p>We studied a large miRNA gene cluster in intron 10 of the mouse Sfmbt2 gene using bioinformatic tools.</p> <p>Results</p> <p>Mice and rats are unique to harbor a 55-65 Kb DNA sequence in intron 10 of the Sfmbt2 gene. This intronic region is rich in regularly repeated B1 retrotransposons together with inverted self-complementary CA/TG microsatellites. The smallest repeats unit, called MSHORT1 in the mouse, was duplicated 9 times in a tandem head-to-tail array to form 2.5 Kb MLONG1 units. The center of the mouse miRNA gene cluster consists of 13 copies of MLONG1. BLAST analysis of MSHORT1 in the mouse shows that the repeat unit is unique for intron 10 of the Sfmbt2 gene and suggest a dual phase model for growth of the miRNA gene cluster: arrangment of 10 MSHORT1 units into MLONG1 and further duplication of 13 head-to-tail MLONG1 units in the center of the miRNA gene cluster. Rats have a similar arrangment of repeat units in intron 10 of the Sfmbt2 gene. The discrepancy between 65 miRNA genes in the mouse cluster as compared to only 1 miRNA gene in the corresponding rat repeat cluster is ascribed to sequence differences between MSHORT1 and RSHORT1 that result in lateral-shifted, less-stable miRNA precursor hairpins for RSHORT1.</p> <p>Conclusion</p> <p>Our data provides new evidence for the emerging concept that lineage-specific retroposons have played an important role in the birth of new miRNA genes during evolution. The large difference in the number of miRNA genes in two closely related species (65 versus 1, mice versus rats) indicates that this species-specific evolution can be a rapid process.</p
Empowering aged - a system for the reintegration of the elderly into workforce
The increase of the elderly population has become a major issue all over the world. This increase affects the society in social, political and economic terms. By absorbing elders back into the active workforce several issues can be resolved easily. When reabsorbing them, they may require special attention due to their age and deteriorating health conditions. Information and Communication Technology (ICT) can play a major role in
helping this elderly population to adapt according to the demanding working conditions of today fast moving world. In this paper the authors present the implementation of a desktop
computer application for the purpose of tracking the health condition by detecting the stress and performance levels. When a userâs stress level goes up or performance level comes down, the early detection of such symptoms will make the professional help
more effective
âStable-on-the-Tableâ Biosensors: Hemoglobin-Poly (Acrylic Acid) Nanogel BioElectrodes with High Thermal Stability and Enhanced Electroactivity
In our efforts toward producing environmentally responsible but highly stable bioelectrodes with high electroactivities, we report here a simple, inexpensive, autoclavable high sensitivity biosensor based on enzyme-polymer nanogels. Met-hemoglobin (Hb) is stabilized by wrapping it in high molecular weight poly(acrylic acid) (PAA, MW 450k), and the resulting nanogels abbreviated as Hb-PAA-450k, withstood exposure to high temperatures for extended periods under steam sterilization conditions (122 °C, 10 min, 17â20 psi) without loss of Hb structure or its peroxidase-like activities. The bioelectrodes prepared by coating Hb-PAA-450k nanogels on glassy carbon showed well-defined quasi-reversible redox peaks at â0.279 and â0.334 V in cyclic voltammetry (CV) and retained >95% electroactivity after storing for 14 days at room temperature. Similarly, the bioelectrode showed ~90% retention in electrochemical properties after autoclaving under steam sterilization conditions. The ultra stable bioelectrode was used to detect hydrogen peroxide and demonstrated an excellent detection limit of 0.5 ÎŒM, the best among the Hb-based electrochemical biosensors. This is the first electrochemical demonstration of steam-sterilizable, storable, modular bioelectrode that undergoes reversible-thermal denaturation and retains electroactivity for protein based electrochemical applications
Tuning HemoglobinâPoly(acrylic acid) Interactions by Controlled Chemical Modification with Triethylenetetramine
Proteinâpolymer interactions play a very important
role
in a number of applications, but details of these interactions are
not fully understood. Chemical modification was introduced here to
tune proteinâpolymer interactions in a systematic manner, where
methemoglobin (Hb) and polyÂ(acrylic acid) (PAA) served as a model
system. Under similar conditions of pH and ionic strength, the influence
of protein charge on Hb/PAA interaction was studied using chemically
modified Hb by isothermal titration calorimetry (ITC). A small fraction
of COOH groups of Hb were amidated with triethylenetetramine (TETA)
or ammonium chloride to produce the corresponding charge ladders of
Hb-TETA and Hb-ammonia derivatives, respectively. All the Hb/PAA complexes
produced here are bioactive, entirely soluble in water, and indicated
the retention of Hb structure to a significant extent. Binding of
Hb to PAA was exothermic (Î<i>H</i> < 0). The binding
of Hb-TETA charge ladder to PAA indicated decrease of Î<i>H</i> from â8 ± 0.2 to â89 ± 4 kcal/mol,
at a rate of â3.8 kcal/mol per unit charge introduced via modification.
The Hb-ammonia charge ladder, in contrast, showed a decrease of Î<i>H</i> from â8 ± 0.2 to â17 ± 1.5 kcal/mol,
at much slower rate of â1.0 kcal/mol per unit charge. Thus,
the amine used for the modification played a strong role in tuning
Hb/PAA interactions, even after correcting for the charge, synergistically.
Charge clustering may be responsible for this synergy, and this interesting
observation may be exploited to construct protein/polymer platforms
for advanced biomacromolecular applications
Design and construction of a low cost air purifier for killing harmful airborne microorganisms using a combination of a strong multi-directional electric-field and an ultra violet light
In this work we have designed and developed a low cost and simple instrument to purify air in an enclosure. The device sucks up the air in the enclosed area, kills the microorganisms and let clean air flow out. A combination of an ultra violet light and an electric field are used to kill the microorganisms in air. Three electric field chambers (radial, parallel, perpendicular) are used to clean air more effectively. Stainless steel meshes were used to increase the density of the electric fields. The outer covers were made with plastic and wood. The instrument was tested against an evaporated bacterial solution (Staphylococcus aureus) by letting it flow through the instrument and measuring the bacterial concentration of the output air. The results showed the instrument is extremely effective even when tested against high bacterial concentrations. The instrument is extremely useful to clean air in closed rooms such as in hospitals, schools, etc. and prevent the spread of airborne diseases