ABSTRACT
Bovine herpesvirus 1 (BoHV-1) is an alphaherpesvirus with a genome of 135 kb. Some BoHV-1 genes are nonessential and may be deleted from the viral genome. Here, a spontaneous gene deletion was identified in the BoHV-1 strain Cooper. Genes of the US1.67/US2 region were absent, as determined by next-generation sequencing.
ABSTRACT
The plasma membrane of cells contains enzymes whose active sites face the external medium rather than the cytoplasm. The activities of these enzymes, referred to as ectoenzymes, can be measured using living cells. In this work we describe the ability of living promastigotes of Leishmania amazonensis to hydrolyze extracellular ATP. In these intact parasites whose viability was assessed before and after the reactions by motility and by trypan blue dye exclusion, there was a low level of ATP hydrolysis in the absence of any divalent metal (5.39 +/- 0.71 nmol P(i)/h x 10(7) cells). The ATP hydrolysis was stimulated by MgCl(2) and the Mg-dependent ecto-ATPase activity was 30.75 +/- 2.64 nmol P(i)/h x 10(7) cells. The Mg-dependent ecto-ATPase activity was linear with cell density and with time for at least 60 min. The addition of MgCl(2) to extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. At 5 mM ATP, half-maximal stimulation of ATP hydrolysis was obtained with 1.21 mM MgCl(2). This stimulatory activity was also observed when MgCl(2) was replaced by MnCl(2), but not by CaCl(2) or SrCl(2). The apparent K(m) for Mg-ATP(2-) was 0.98 mM and free Mg(2+) did not increase the ecto-ATPase activity. In the pH range from 6.8 to 8.4, in which the cells were viable, the acid phosphatase activity decreased, while the Mg(2+)-dependent ATPase activity increased. This ecto-ATPase activity was insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin A(1), ouabain, furosemide, vanadate, molybdate, sodium fluoride, tartrate, and levamizole. To confirm that this Mg-dependent ATPase was an ecto-ATPase, we used an impermeant inhibitor, 4,4'-diisothiocyanostylbene 2',2'-disulfonic acid as well as suramin, an antagonist of P(2) purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg(2+)-dependent ATPase activity in a dose-dependent manner. A comparison between the Mg(2+)-dependent ATPase activity of virulent and avirulent promastigotes showed that avirulent promastigotes were less efficient than the virulent promastigotes in hydrolyzing ATP.
Subject(s)
Adenosine Triphosphatases/metabolism , Adenosine/metabolism , Leishmania/enzymology , Acid Phosphatase/metabolism , Adenosine Triphosphate/metabolism , Animals , Hydrogen-Ion Concentration , Hydrolysis , Leishmania/metabolism , Leishmania/pathogenicity , Suramin/pharmacology , Trypanocidal Agents/pharmacology , VirulenceABSTRACT
Antecedentes: El embarazo en adolescentes constituye un serio problema de salud en nuestras jovenes marginadas. Materiales y métodos: Seleccionamos una muestra de 173 adolescentes entre 13 y 19 años de edad, residentes en el Barrio Simón Bolívar de la ciudad de Sanro Domingo, que representa un 9.8// de ellas en este barrio, habitado por una población socioeconómica de clase baja. Resultados: Todas las adolescentes entrevistadas habían estado embarazadas por lo menos una vez, 42.8// de ellas se habían practicado un aborto y 8.7// mas de uno (en total 51.5// se habían practicado abortos). Conclusión: Es necesario urgentemente una campaña de educación sexual y elevación de los niveles morales y espirituales en este segmento de la población