An adaptation of the Comet-assay was developed which enables the discrimination of viable, apoptotic and necrotic single cells by use of the common Annexin-V staining and a dye exclusion test on the cells already embedded in agarose gel on glass slides. Membrane integrity (Ethidium-Homodimer exclusion), cellular esterase activity (Calcein blue-AM) as well as translocation of phosphadidyl-serine...

Introduction: Harbingers of doom or prophesy for the ancient peoples of Earth, comets are now understood to be primordial fragments from our Solar System's birth composed of various ices and dust species. Among the questions surrounding comets and their elusive character are the properties and processes of the rarefied gasses and disperse dust that surround their solid nucleus. Dusty, or comple...

This paper utilizes Aubry-Mather theory to construct instability regions for a certain three body problem. We consider a Sun-Jupiter-Comet system and under some simplifying assumptions and show the existence of instabilities for orbit of the comet. In particular we show that a comet which starts close to orbit of an ellipse of eccentricity e = 0.748 can increase in eccentricity up to e = 0.826....

The calculations made by Euler for the orbital parameters Comet of 1742 are revisited. These were published in Latin E58—Determinatio orbitae cometae qui mense Martio huius anni potissimum fuit observatus (Determination orbit comet which was clearly observed month March 1742). present work begins giving some background on comets before addressing main topic itself, consists calculation assumed ...

The nucleus of comet C/1996 J1, whose duplicity was first detected in early May 1997, ∼ 4 months after perihelion, is found to have split nontidally∼ 70 days before perihelion at 1.65 AU from the Sun. The secondary nucleus, discovered when in outburst and subsequently observed for 8 2 months, had separated from the primary nucleus at a rate of 1.7 m/s and drifted away from it with a radial nong...

BACKGROUND Comet assay and micronucleus test have been used increasingly to evaluate the genotoxicity of many metals and their organic compounds in aquatic ecosystems. The use of endemic aquatic organisms as biological sentinels has proved useful in environmental monitoring. In this study, the genetic damage caused by methylmercury (MeHg) in Aequidens tetramerus (commonly called acará-sela) was...

Mad2 is a key component of the spindle assembly checkpoint (SAC) that delays the onset of anaphase until all kinetochores are attached to the spindle. It binds to Cdc20 and prevents it from promoting destruction of an anaphase inhibitor, Securin. Previously, we showed that a Mad2-binding protein, p31(comet), formed a complex with Mad2 upon the completion of spindle attachment. Here, we showed t...

[1] We investigate the plasma environment of comet 67P/Churyumov-Gerasimenko, the target of the European Space Agency’s Rosetta mission. Rosetta will rendezvous with the comet in 2014 at almost 3.5 AU and follow it all the way to and past perihelion at 1.3 AU. During its journey towards the inner solar system the comet’s environment will significantly change. The interaction of the solar wind w...

The single-cell gel/comet assay is an electrophoretic technique used to detect single-strand breaks in DNA. Damage is assessed examining individual cells under an epifluorescent microscope. UV-induced DNA damage consists mostly of the formation of pyrimidine dimers; therefore, most of the damage cannot be detected using a standard comet assay. The enzyme T4 endonuclease V breaks DNA strands at ...

The comet assay (single-cell gel electrophoresis) has been established as a simple, rapid, flexible and sensitive method of detecting DNA damage in single cells(1,2). Cells embedded in agarose on a microscope slide are lysed with detergent. Electrophoresis at high pH results in structures resembling comets, observed by fluorescence microscopy; the intensity of the comet tail relative to the hea...