Use of the direct epifluorescent filter technique for the enumeration of yeasts

The ability of the direct epifluorescent filter technique (DEFT) to enumerate the viable numbers of various species of yeasts was evaluated. A DEFT count could be made in less than 10 min and the DEFT counts of non-heat-treated samples agreed well with plate counts. The DEFT was unsuitable for the enumeration of yeasts in heat-treated samples because non-viable cells fluoresced orange. A double staining technique using Janus Green B and acridine orange was developed to overcome this problem. The modified DEFT enabled viable and non-viable yeasts to be differentiated in heat-treated samples of pure cultures and improved the relationship between the DEFT count and plate count. The method proved to be of little value, however, for use with beverage products because of unreliable staining patterns.     

Chloroplast isolation from Laminaria digitata (Phaeophyceae): A reproducible methodology yielding photosynthetically active chloroplasts

A technique for chloroplast isolation from the brown algae macrophyte Laminaria digitata (Phaeophyceae) is described which results in stable and photo-synthetically active chloroplasts. Chloroplasts in L. digitata are mainly located in the surface layer meristodermic cells. The expanded intercellular regions of the cortex tissue contain abundant mucilage which is exuded during mechanical tissue disruption. The method described for chloroplast isolation is based on appropriate isolation buffers and the removal of mucilage which is secreted during tissue disruption, and it may be applicable to other macroalgae with large amounts of mucilage. The isolated chloroplasts showed stable oxygen-evolving activities. The reproducibility of this technique was established by analysis of electron transport and evaluation of the activities of photosystems I and II.Abbreviations BSA bovine serum albumin - DCPIP 2,6-dichlorophenol-indophenol - DMBQ 2,6-dimethyl-benzoquinone - MV methyl viologen We thank Mr. D. Cameron and Mr. R. Wilkie (University Marine Biological Station Millport, Isle of Cumbrae, Scotland) for supplying Laminaria digitata and Mr. J. Pacy (King's College London, UK) for assistance with electron microscopy. This work was supported by EC (Brussels) grant CT/0770 and a fellowship from CNPq (Brasilia) to M. A. Rodrigues.     

Phylogenetic relationships,population demography,and species delimitation of the Alouatta belzebul species complex (Atelidae: Alouattinae)

Primates - Howler monkeys (genus Alouatta) exhibit the most extensive distribution among platyrrhines, comprising Mesoamerican and South American species groups, with the South American group...     

Narratives of Positionality in Primatology: Foreign/Range–Country Collaborator Perspectives from Africa and South America

International Journal of Primatology - Primate research and conservation may inadvertently reproduce neocolonial dynamics when primatologists from affluent, imperialist nations conduct studies in...     

In vitro morphophysiological responses of Alternanthera tenella colla (Amaranthaceae) to stress induced by cadmium and the attenuating action of silicon

Plant Cell, Tissue and Organ Culture (PCTOC) - Despite having the ability to bioaccumulate trace elements such as cadmium (Cd), many species also present morphophysiological disorders that can...     

Comparing scapular morphology of Amblyomma sculptum and Amblyomma dubitatum nymphs allows a fast and practical differential diagnosis of ticks in highly infested areas with dominance of these two species

Rickettsia rickettsii infection causes the highest human fatality rate among all Rickettsia species of the world and is endemic in Southeast Brazil. In this part of the country most human spotted fever cases are related to unnaturally high populations of ticks, usually a mix of two species, Amblyomma dubitatum Neumann and Amblyomma sculptum Berlese and their local host, capybara (Hydrochoerus hydrochaeris). At the same time, an increase in the number of SF notifications as well as its urbanization was observed, and a better characterization of disease epidemiology is mandatory for control measures and to halt its expansion. It was recently noticed in southeast Brazil that SF endemic areas were characterized by overgrowth populations of A. sculptum and decreased populations of A. dubitatum. Hence, characterization of areas with potential to endemicity, eco-epidemiological studies and control measures may rely on the evaluation of A. sculptum/A. dubitatum rate. However, in potentially endemic scenarios, discriminating the two tick species, particularly the nymphs considered the main vector stage, is a challenge in face of several hundreds to thousands of ticks that should be examined for quantitative studies. We herein present additional morphological features to an existing identification key for Amblyomma nymphs that considerably diminishes the labor to distinguish nymphs of these two tick species. Specifically, the oval-shaped scutum of A. dubitatum and a conspicuous scapula of A. sculptum are prominent discriminating features.