Regulation of nuclear mechanics and the impact on DNA damage

In eukaryotic cells, the nucleus houses the genomic material of the cell. The physical properties of the nucleus and its ability to sense external mechanical cues are tightly linked to the regulation of cellular events, such as gene expression. Nuclear mechanics and morphology are altered in many diseases such as cancer and premature ageing syndromes. Therefore, it is important to understand how different components contribute to nuclear processes, organisation and mechanics, and how they are misregulated in disease. Although, over the years, studies have focused on the nuclear lamina—a mesh of intermediate filament proteins residing between the chromatin and the nuclear membrane—there is growing evidence that chromatin structure and factors that regulate chromatin organisation are essential contributors to the physical properties of the nucleus. Here, we review the main structural components that contribute to the mechanical properties of the nucleus, with particular emphasis on chromatin structure. We also provide an example of how nuclear stiffness can both impact and be affected by cellular processes such as DNA damage and repair

Role Of Disorder In The Conduction Mechanism In Polyanilines

We present the first theoretical calculations of the electronic structure of long (200 rings) linear chains of polyaniline, ranging in composition from leucoemeraldine to emeraldine, allowing for compositional disorder in that the sequence of quinoid-benzenoid groups is random. We show that random protonation of the disordered polymers may induce p-type conductivity: This process pulls the Fermi energy down into the valence band, past localized band tails, to extended states. The effect is only seen if disorder is taken into account. © 1989 The American Physical Society.63778678

A fragilidade da população idosa

O desenvolvimento populacional de idosos contribuindo para o aumento de sua vulnerabilidade, decorrente do avanço da idade. Esta revisão relacionou idosos em Instituições de Longa Permanência para Idosos (ILPIs) e com alto índice de depressão, em razão de que essas doenças prejudicam sua qualidade de vida, tornando-os mais vulneráveis a essas situações, por se sentirem totalmente incapazes de enfrentá-las. Sendo assim, esse trabalho tem como objetivo reforçar a importância de profissionais da saúde capacitados para lidar com esses idosos, para que não haja uma piora no quadro clínico ou que leve a óbito por conta dessas doenças

Alterations In The Achilles Tendon After Inflammation In Surrounding Tissue

Objective: To analyze the characteristics of the Achilles tendon of rats after induction of localized inflammation in the rat paw. Methods: In our study three groups were used: inflamed group with carrageenan in rat paw (G1); saline group (G2) and control group (G3). After 4 hours the animals were euthanized and the Achilles tendon removed. Results: No significant differences were observed in the analysis of non-collagenous proteins, glycosaminoglycans and hydroxyproline in the groups but a tendency of reduction was verified in G1. As regards the organization of collagen molecules, no differences were observed between groups. With respect to MMPs activity, a stronger presence of the active isoform of MMP-2 in G1 was observed, suggesting that the remodeling was occurring. Conclusion: Thus, we conclude that the inflammatory process in rat paw may affect the remodeling of tendons located near the inflamed site.205266269Maffulli, N., Kader, D., Tendinopathy of tendo Achillis (2002) J Bone Joint Surg Br, 84 (1), pp. 1-8Maffulli, N., Rupture of the Achilles tendon (1999) J Bone Joint Surg Am, 81 (7), pp. 1019-1036Järvinen, T.A., Kannus, P., Maffulli, N., Khan, K.M., Achilles tendon disorders: etiology and epidemiology (2005) Foot Ankle Clin, 10 (2), pp. 255-266Oliveira, F.S., Pinfildi, C.E., Parizoto, N.A., Liebano, R.E., Bossini, P.S., Garcia, E.B., Effect of low level laser therapy (830 nm) with different therapyregimes on the process of tissue repair in partial lesion calcaneous tendon (2009) Lasers Surg Med, 41 (4), pp. 271-276Karousou, E., Ronga, M., Vigetti, D., Passi, A., Maffulli, N., Collagens, proteoglycans, MMP-2, MMP-9 and TIMPs in human Achilles tendon rupture (2008) Clin Orthop Relat Res, 466 (7), pp. 1577-1582Riley, G., Matrix metalloproteinase activities and their relationship with collagen remodelling in tendon pathology (2002) Matrix Biol, 21 (2), pp. 185-195Dario, B.E., Barquilha, G., Marques, R.M., Lesões esportivas: um estudo com atletas de basquetebol Bauruense (2010) Rev Bras Cienc Esporte, 31 (3), pp. 205-215Vieira, C.P., Aro, A.A., Almeida, M.S., de Mello, G.C., Antunes, E., Pimentel, E.R., Effects of acute inflammation induced in the rat paw on the deep digital flexor tendon (2012) Connect Tissue Res, 53 (2), pp. 160-168Tillander, B., Franzén, L.E., Nilsson, E., Norlin, R., Carrageenan-induced subacromial bursitis caused changes in the rat's rotator cuff (2001) J Orthop Res, 19 (3), pp. 441-447Winter, C.A., Risley, E.A., Nuss, G.W., Carrageenin-induced edema in hind paw of the rat as an assay for antiiflammatory drugs (1962) Proc Soc Exp Biol Med, 111, pp. 544-547Bradford, M.M., A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding (1976) Anal Biochem, 72, pp. 248-254Farndale, R.W., Buttle, D.J., Barrett, A.J., Improved quantitation and discrimination of sulphated glycosaminoglycans by use of dimethylmethylene blue (1986) Biochim Biophys Acta, 883 (2), pp. 173-177Marqueti, R.C., Parizotto, N.A., Chriguer, R.S., Perez, S.E., Selistre-de-Araujo, H.S.A., ndrogenic-anabolic steroids associated with mechanical loading inhibit matrix metallopeptidase activity and affect the remodeling of the achilles tendon in rats (2006) Am J Sports Med, 34 (8), pp. 1274-1280Vidal, B.C., Mello, M.L., Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers (2005) Biopolymers, 78 (3), pp. 121-128Riley, G., Tendinopathy:from basic science to treatment (2008) Nat Clin Pract Rheumatol, 4 (2), pp. 82-89Szabo, K.A., Ablin, R.J., Singhingh, G., Matrix metalloproteinases and the immune response (2004) Clin Appl Immun Rev, 4, pp. 295-319Chakraborti, S., Mandal, M., Das, S., Mandal, A., Chakraborti, T., Regulation of matrix metalloproteinases: an overview (2003) Mol Cell Biochem, 253 (1-2), pp. 269-285Magra, M., Maffulli, N., Matrix metalloproteases: a role in overuse tendinopathies (2005) Br J Sports Med, 39 (11), pp. 789-791Clutterbuck, A.L., Harris, P., Allaway, D., Mobasheri, A., Matrix metalloproteinases in inflammatory pathologies of the horse (2010) Vet J, 183 (1), pp. 27-38Marsolais, D., Duchesne, E., Côté, C.H., Frenette, J., Inflammatory cells do not decrease the ultimate tensile strength of intact tendons in vivo and in vitro: protective role of mechanical loading (2007) J Appl Physiol, 102 (1), pp. 11-1

New qnr Gene Cassettes Associated with Superintegron Repeats in Vibrio cholerae O1

A novel qnr determinant emerged in ciprofloxacin-resistant Vibrio cholerae O1 from the Amazon region of Brazil. This qnrVC1 was in a typical class 1 integron. Its attC showed 89% identity with V. parahaemolyticus superintegron repeats. Analysis showed V. cholerae O1 carrying qnrVC2 associated with a V. cholerae superintegron repeat

Competition between two high- and low-affinity protein-binding sites in myosin VI controls its cellular function.

Myosin VI is involved in many cellular processes ranging from endocytosis to transcription. This multifunctional potential is achieved through alternative isoform splicing and through interactions of myosin VI with a diverse network of binding partners. However, the interplay between these two modes of regulation remains unexplored. To this end, we compared two different binding partners and their interactions with myosin VI by exploring the kinetic properties of recombinant proteins and their distribution in mammalian cells using fluorescence imaging. We found that selectivity for these binding partners is achieved through a high-affinity and a low-affinity motif within myosin VI. These two motifs allowed competition among partners for myosin VI. Exploring how this competition affects the activity of nuclear myosin VI, we demonstrate the impact of a concentration-driven interaction with the low-affinity binding partner DAB2, finding that this interaction blocks the ability of nuclear myosin VI to bind DNA and its transcriptional activity in vitro. We conclude that loss of DAB2, a tumor suppressor, may enhance myosin VI–mediated transcription. We propose that the frequent loss of specific myosin VI partner proteins during the onset of cancer leads to a higher level of nuclear myosin VI activity

Dengue Virus 3 Genotype I in Aedes aegypti Mosquitoes and Eggs, Brazil, 2005–2006

Dengue virus type 3 genotype I was detected in Brazil during epidemics in 2002–2004. To confirm this finding, we identified this virus genotype in naturally infected field-caught Aedes aegypti mosquitoes and eggs. Results showed usefulness of virus investigations in vectors as a component of active epidemiologic surveillance

Passatempo Virus, a Vaccinia Virus Strain, Brazil

Passatempo virus was isolated during a zoonotic outbreak. Biologic features and molecular characterization of hemagglutinin, thymidine kinase, and vaccinia growth factor genes suggested a vaccinia virus infection, which strengthens the idea of the reemergence and circulation of vaccinia virus in Brazil. Molecular polymorphisms indicated that Passatempo virus is a different isolate

Desempenho de Trichogramma pratissolii Querino & Zucchi (Hymenoptera, Trichogrammatidae) em ovos de Anagasta kuehniella (Zeller) (Lepidoptera, Pyralidae) sob efeito de Bacillus thuringiensis Berliner

Visando estudar o efeito da bactéria entomopatogênica Bacillus thuringiensis (Bt) sobre fêmeas adultas de Trichogramma pratissolii e sua progênie, este trabalho foi realizado com diferentes isolados de Bt e Bt kurstaki misturados ao alimento fornecido para o parasitóide antes de parasitar ovos de Anagasta kuehniella. Para tanto, suspensões de seis isolados de Bt E-3, E-10, E-15, E-16, E-19, E-20 e o Bt kurstaki foram misturados em gotícula de mel (1:1), como fonte de alimento e mel puro como testemunha, e, em seguida, foram oferecidos simultaneamente cartelas com ovos do hospedeiro para o parasitismo. Foram utilizadas 20 repetições por tratamento. O experimento foi mantido em câmara climatizada a 25 ? 1masculineC, UR 70 ? 10% e fotofase de 14h. Foram avaliados os parasitismos diários, totais e acumulados; sobrevivência; emergência e razão sexual da progênie. Os tratamentos não afetaram o parasitismo, razão sexual e a longevidade, porém em alguns tratamentos (E-3, E-10, E-16 e E-20) foi observado efeito indireto sobre a emergência da progênie, o que implicaria a necessidade de mais liberações massais do parasitóide para alcançar os resultados esperados. Por outro lado, a aceleração do parasitismo verificada em todos os tratamentos sugere que adultos de T. pratissolii, quando submetidos à pressão de algum fator externo tendem a parasitar o mais rápido possível para assegurar a sobrevivência da progênie. Portanto, a combinação Bt + T. pratissolii pode favorecer a atuação do parasitóide em campo, principalmente em casos em que é necessária uma rápida redução dos níveis populacionais da praga