Transferability of SSR markers from related Uredinales species to the coffee rust Hemileia vastatrix.

The aim of the present research was to test the transferability of simple sequence repeat (SSR) markers developed in two Uredinales species to Hemileia vastatrix, coffee rust. The development of efficient techniques for the identification of H. vastatrix isolates is imperative, given the continuous development of new races. The transferability of 25 SSR markers developed in the related Uredinales species Puccinia coronata f. sp lolli and Melampsora linii to H. vastatrix was tested. A low level of transferability of SSRs was detected, and only 4 potential markers that can be used to fingerprint the coffee rust races were identified.

IgA reactivity in patients with intestinal or hepatic amebiasis.

The antigens of E. histolytica recognized by IgA antibodies in sera from patients with either amebic liver abscess or intestinal amebiasis, as well as saliva from the latter, were determined in immunoblots of whole native trophozoite proteins. Results show that sera of patients with amebic liver abscess reacted mainly with amebic proteins of more than 200 kDa, whereas those of individuals with intestinal amebiasis recognized a protein of 145 kDa. The saliva of the latter detected a protein of 210 kDa which is not always seen when using the sera of patients with intestinal or hepatic amebiasis.

Charybdotoxin and apamin sensitivity of the calcium-dependent repolarization and the afterhyperpolarization in neostriatal neurons.

1. Intracellular recordings from neostriatal neurons in an in vitro slice preparation of the rat brain were used to analyze the pharmacological sensitivity of the action potential (AP) repolarization and the afterhyperpolarization (AHP) that follows a single action potential. The interspike voltage trajectory and the AHP could be divided into two main parts: a fast component lasting a few milliseconds and better observed during a train of spikes, and a slow component lasting approximately 250 ms and that comprises the main portion of the AHP. In some cells, a slow (up to 1 s) component of low amplitude was also detected. 2. Single APs were elicited at two imposed membrane potentials (around -60 and around -80 mV). The AP amplitude was larger, the repolarization rate was faster, and the duration was shorter when spikes were evoked at -80 mV. When measured from the -60 mV holding potential, the afterpotential was an AHP with peak amplitude of -5 mV. The afterpotential became a delayed depolarization (DD) at -80 mV. 3. Firing frequency adaptation was voltage sensitive. The firing of APs induced by long intracellular current pulses from a holding potential of -80 mV exhibited only a slow-frequency adaptation (time constant of seconds). However, at -60 mV, an initial and faster frequency adaptation was evident (time constant of tens of milliseconds). 4. The Ca2+ channel blocker Cd2+ retarded AP repolarization rate. This effect correlated with a significant block of the fast and slow components of the AHP. In contrast, Ni2+ had no significant effects on the same parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Identificación y análisis de secuencias de retrotransposones / Identification and Analysis of Retrotransposon Sequences in Lycopersicon spp

Secuencias de retrotransposones del tipo Ty3/gypsy fue-ron identificadas en los genomas de tomate (Lycopersicon esculentum) y otras especies de Lycopersicon por medio de análisis de PCR. Las secuencias fueron altamente he-terogéneas, como ha sido el caso para otras secuencias de retrotransposones identificadas en plantas. Un análisis de las secuencias amplificadas por PCR mostró que la filogenia de las secuencias Ty3/gypsy de tomate fue simi-lar a la del género Lycopersicon. Este análisis también mostró que las secuencias pertenecen a secuencias de retrotransposones de lenta evolución y que parecen ser residentes desde tiempos ancestrales del genoma del to-mate. Se obtuvo alguna evidencia que sugiere que los ele-mentos del tipo Ty3/gypsy en tomate podrían ser activos. Las líneas de evidencia en favor de la presencia de retrotransposones activos en tomate y su posible transmi-sión horizontal se analizan más profundamente.