Cardiac adaptations of bullfrog tadpoles in response to chytrid infection.

The chytrid fungus Batrachochytrium dendrobatidis (Bd) can result in heart failure in Bd-susceptible species. Since Bd infection generally does not cause mortality in North American bullfrogs, the aim of this work was to verify whether this species presents any cardiac adaptation that could improve the tolerance to the fungus. Thus, we analyzed tadpoles' activity level, relative ventricular mass, ventricle morphology, in loco heart frequency, and in vitro cardiac function. The results indicate that infected animals present an increase in both ventricular relative mass and in myofibrils' incidence, which accompanied the increase in myocytes' diameter. Such morphological alterations enabled an increase in the in vitro twitch force that, in vivo, would result in elevation of the cardiac stroke volume. This response requires much less energy expenditure than an elevation in heart frequency, but still enables the heart to pump a higher volume of blood per minute (i.e., an increase in cardiac output). As a consequence, the energy saved in the regulation of the cardiac function of Bd-infected tadpoles can be employed in other homeostatic adjustments to avoid the lethal effect of the fungus. Whether other species present this ability, and to what extent, remains uncertain, but such possible interspecific variability might explain different mortality rates among different species of Bd-infected amphibians.

Correlation between API 50 CH and multiplex polymerase chain reaction for the identification of vaginal lactobacilli in isolates

Identification of Lactobacillus sp. strains by phenotypic methods may lead to doubtful results possibly interfering in the reliability of the epidemiological and probiotics studies. Therefore this study aimed to determine the best methodology for the identification of the large diversity of lactobacilli species found in the vagina by comparing two techniques, one based on their biochemical profile and other employing molecular biology. A carbohydrate fermentation test (API 50 CH) was compared with multiplex polymerase chain reaction (PCR) for the identification of species of vaginal lactobacilli from 135 healthy women. The kappa index was used to evaluate agreement between the methods. Using the molecular technique, L. crispatus (32.6 percent), L. jensenii (25 percent) and L. gasseri (20.6 percent) were the most frequent species. However, using the biochemical technique, the most frequent species were: L. acidophilus (34.8 percent), L. crispatus (27.2 percent) and L. fermentum (13 percent). Although L. acidophilus was the most frequent specie found by biochemical tests, no strain of this microorganism was detected by PCR. Agreement between the methods was low for identification of all the most common species. Although rates of L. crispatus detected were similar using both methods (32.6 percent and 27.2 percent), agreement between them was relatively low (kappa = 0.52). Conclusions: Our results confirmed the limitation of the biochemical method and the applicability of a previously published molecular method (Multiplex PCR) for the identification of lactobacilli in the vaginal tract, focusing on further necessity of its improvement for also targeting L. vaginalis and L. iners.

Correlation between api 50 ch and multiplex polymerase chain reaction for the identification of vaginal lactobacilli in isolates.

UNLABELLED: Identification of Lactobacillus sp. strains by phenotypic methods may lead to doubtful results possibly interfering in the reliability of the epidemiological and probiotics studies. Therefore this study aimed to determine the best methodology for the identification of the large diversity of lactobacilli species found in the vagina by comparing two techniques, one based on their biochemical profile and other employing molecular biology. A carbohydrate fermentation test (API 50 CH) was compared with multiplex polymerase chain reaction (PCR) for the identification of species of vaginal lactobacilli from 135 healthy women. The kappa index was used to evaluate agreement between the methods. Using the molecular technique, L. crispatus (32.6%), L. jensenii (25%) and L. gasseri (20.6%) were the most frequent species. However, using the biochemical technique, the most frequent species were: L. acidophilus (34.8%), L. crispatus (27.2%) and L. fermentum (13%). Although L. acidophilus was the most frequent specie found by biochemical tests, no strain of this microorganism was detected by PCR. Agreement between the methods was low for identification of all the most common species. Although rates of L. crispatus detected were similar using both methods (32.6% and 27.2%), agreement between them was relatively low (kappa = 0.52). CONCLUSIONS: Our results confirmed the limitation of the biochemical method and the applicability of a previously published molecular method (Multiplex PCR) for the identification of lactobacilli in the vaginal tract, focusing on further necessity of its improvement for also targeting L. vaginalis and L. iners.