Ana S Ramírez

Publications (6)13.27 Total impact

• Article: A diagnostic polymerase chain reaction for Mycoplasma iowae using primers located in the intergenic spacer region and the 23S rRNA gene.

  Ana S Ramírez, Cynthia Dare, Christine A Yavari, Janet M Bradbury
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  ABSTRACT: Mycoplasma iowae is primarily a pathogen of turkeys and, although uncommon, it still persists in some areas of the world, where it may cause embryo mortality and leg lesions. A species-specific diagnostic polymerase chain reaction was developed using a forward primer based in the intergenic spacer region between the 16S rRNA and the 23S rRNA ribosomal genes and a reverse primer located within the 23S rRNA gene. The polymerase chain reaction proved to be both sensitive and specific. It detected M. iowae DNA in the six reference strains of serotypes I, J, K, N, Q and R and in 28 field isolates. With the six serotypes the test detected between 1 and 5 pg of M. iowae DNA. There were no non-specific reactions with the other avian Mycoplasma species. When the closest phylogenetically related species were checked, a weak reaction with Mycoplasma muris was observed that disappeared when the annealing temperature was increased by 2°C.
  Avian Pathology 06/2012; 41(3):317-22. · 1.71 Impact Factor
• Article: Mycoplasma neophronis sp. nov., isolated from the upper respiratory tract of Canarian Egyptian vultures (Neophron percnopterus majorensis).

  A Suárez-Pérez, A S Ramírez, R S Rosales, P Calabuig, C Poveda, R Rosselló-Móra, R A J Nicholas, J B Poveda
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  ABSTRACT: Six strains with the typical characteristics of mycoplasmas were isolated from the tracheae of six Canarian Egyptian vultures (Neophron percnopterus majorensis). The results of biochemical, serological and molecular genetic studies showed that the isolates were nearly identical and that they could be considered as representing a novel species of the genus Mycoplasma. Colonies possessed the typical fried-egg appearance and electron micrographs revealed a pleomorphic cellular morphology with the lack of a cell wall. The isolates hydrolysed arginine and required sterol for growth but did not ferment glucose or hydrolyse urea. We propose that the isolates be assigned to a novel species,Mycoplasma neophronis sp. nov. The type strain is G.A.(T) ( = DSM 24097(T) = ATCC BAA-2157(T)). The antiserum of strain G.A.(T) has been deposited in the Mollicutes collection at Purdue University (Indiana, USA).
  INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 08/2011; 62(Pt 6):1321-5. · 2.11 Impact Factor
• Article: A semi-defined medium without serum for small ruminant mycoplasmas.

  Ana S Ramírez, Juan Luis Fleitas, Rubén S Rosales, Carlos Poveda, Christian de la Fe, Marisa Andrada, Ayoze Castro, José B Poveda
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  ABSTRACT: The composition of the medium used to cultivate Mycoplasma species is very important. Serum is one of the most important additives as it contains lipids (cholesterol) and serum proteins, which are essential for the growth of the organisms. This work reports the development of a semi-defined medium, called MWS (Medium Without Serum) produced without animal serum and bovine serum albumin. MWS seems to be suitable for cultivating several species of caprine mycoplasma, especially M. mycoides subsp. mycoides (LC) and M. mycoides subsp. capri.
  The Veterinary Journal 04/2008; 178(1):149-52. · 2.24 Impact Factor
• Article: Development and evaluation of a diagnostic PCR for Mycoplasma synoviae using primers located in the intergenic spacer region and the 23S rRNA gene.

  Ana S Ramírez, Clive J Naylor, Philip P Hammond, Janet M Bradbury
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  ABSTRACT: Mycoplasma synoviae (Ms) is an important pathogen of poultry, causing economic losses to this industry. Early and reliable diagnosis is a key to controlling the spread of this organism. In this study, a polymerase chain reaction with one primer based on the intergenic spacer region (ISR) was validated for detection of Ms. The ISR primer was paired with a general primer from within the 23S rRNA gene. The PCR primers were tested with the 22 other recognised avian Mycoplasma species to check the specificity and with 21 field isolates of Ms from various hosts and countries, and with several swab samples. The PCR appeared to be specific and sensitive. Four different sample preparation methods were compared for use in this PCR, and the amplification protocol was compared with three others, confirming the comparative sensitivity of the new PCR.
  Veterinary Microbiology 12/2006; 118(1-2):76-82. · 3.33 Impact Factor
• Article: A putative transposase gene in the 16S-23S rRNA intergenic spacer region of Mycoplasma imitans.

  Ryô Harasawa, David G Pitcher, Ana S Ramírez, Janet M Bradbury
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  ABSTRACT: Examination of the nucleotide sequences of the 16S-23S intergenic transcribed spacer (ITS) region of Mycoplasma imitans and Mycoplasma gallisepticum identified a putative transposase gene located only in the ITS of M. imitans, which can be used as a genetic marker to distinguish these two species. The relative size of the PCR products of the ITS region allowed a clear distinction to be made between strains of M. imitans and M. gallisepticum, both of which could be readily discriminated from the type strains of all the other recognized avian Mycoplasma species. In addition, the putative transposase gene assigned in the ITS of M. imitans was shown to include a sequence homologous to that of the P75 gene of M. gallisepticum. This is believed to be the first description of an insertion element in the rRNA operon region of a mycoplasma species.
  Microbiology 05/2004; 150(Pt 4):1023-9. · 3.06 Impact Factor
• Article: Inactivation of Mycoplasma species involved in contagious agalactia.

  Christian de la Fe, Patricia Assuncão, Ana S Ramírez, Jose B Poveda
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  ABSTRACT: The suitability of 5 agents for the inactivation of different field strains of the four mycoplasma species associated with contagious agalactia syndrome in goats, i.e. Mycoplasma agalactiae, Mycoplasma mycoides subsp. mycoides LC, Mycoplasma capricolum subsp. capricolum and Mycoplasma putrefaciens, was investigated. Immunoprophylaxis of this syndrome is still based on inactivated vaccines, which traditionally use formalin as the inactivating agent. Moreover, the limited information existing about this type of vaccine is only based on assays against Mycoplasma agalactiae. Our results showed that formalin (0.1%, 37 degrees C during 16 hours) and phenol (0.5%, 24 hours) were effective against all species tested. Surprisingly, binary ethileneimine (BEI), a classical virus-inactivating agent, also proved to be very effective when it was used in a 0.1 M concentration over 24 hours. With heat treatment, every species was inactivated at 60 degrees C. No satisfying results were obtained with purified saponin. To evaluate the harmful effects of each agent on mycoplasmal proteins, a representative strain was subjected to an effective inactivation protocol with each agent, which was monitored by Western immunoblotting. Immunoblotting was performed using sera of animals inoculated with the respective mycoplasma species, to compare the effect of all the agents on treated strains with untreated strains. The results confirmed that phenol, BEI and to a lesser extent also formalin inactivated all species without causing a significant damage while heat caused stronger damage on surface proteins. Future in vivo studies should be conducted because, as recently shown, the combined use of a suitable inactivant and adjuvant could give rise to the induction of certain cytokines and strong antibody production of a specific isotype pattern, thus opening ways to develop more efficacious inactivated vaccines against contagious agalactia.
  Berliner und Münchener tierärztliche Wochenschrift 117(1-2):1-5. · 0.82 Impact Factor