Susceptibility to Phosphomycin as a Differential Character for Gram Negative Anaerobic Bacilli

On the basis of their sensitivity to phosphomycin, various species of anaerobic Gram negative bacilli examined fell into one of two groups. All strains of Bacteroides were resistant to 500 umg/ml whereas strains of Fusobacterium were uniformly sensitive to 62.5 μg/ml. Disc sensitivity testing to phosphomycin at concentrations of 200–500 μg/ml provides a reliable and rapid means of distinguishing fusobacteria from bacteroides.     

Unravelling the migration and moult strategies of a long-distance migrant using stable isotopes: Red Knot Calidris canutus movements in the Americas

For long‐distance migrants, such as many of the shorebirds, understanding the demographic implications of behavioural strategies adopted by individuals is key to understanding how environmental change will affect populations. Stable isotopes have been used in the terrestrial environment to infer migratory strategies of birds but rarely in marine or estuarine systems. Here, we show that the stable isotope ratios of carbon and nitrogen in flight feathers can be used to identify at least three discrete wintering areas of the Red Knot Calidris canutus on the eastern seaboard of the Americas, ranging from southeastern USA to Patagonia and Tierra del Fuego. In spring, birds migrate northwards via Delaware Bay, in the northeastern USA, the last stopping point before arrival in Arctic breeding areas, where they fatten up on eggs of spawning Horseshoe Crabs Limulus polyphemus. The isotope ratios of feather samples taken from birds caught in the Bay during May 2003 were compared with feathers obtained from known wintering areas in Florida (USA), Bahia Lomas (Chile) and Rio Grande (Argentina). In May 2003, 30% of birds passing through the Bay had Florida‐type ‘signatures’, 58% were Bahia Lomas‐type, 6% were Rio Grande‐type and 7% were unclassified. Some of the southern wintering birds had started moulting flight feathers in northern areas, suspended this, and then finished their moult in the wintering areas, whereas others flew straight to the wintering areas before commencing moult. This study shows that stable isotopes can be used to infer migratory strategies of coastal‐feeding shorebirds and provides the basis for identifying the moult strategy and wintering areas of birds passing through Delaware Bay. Coupled with banding and marking birds as individuals, stable isotopes provide a powerful tool for estimating population‐specific demographic parameters and, in this case, further our understanding of the migration systems of the declining Nearctic populations of Red Knot.     

FLUORESCENT MEASUREMENTS OF DNA, RNA AND PROTEINS TO PERFORM COMPARATIVE ANALYSES OF MICROBIAL COMMUNITIES FROM THE ENVIRONMENTS

Simple and rapid methods for the quantification of DNA, RNA and proteins using specific fluorescent dyes are proposed for the comparison and monitoring of microbial communities from the environment. The purpose of this study was the use of straightforward in situ methods which voided the need for preservation of samples and the risk of potential degradation and quantitative changes during transportation. Aside from this, methods used to obtain information on environmental microbial communities are generally time-consuming and present certain difficulty above all when working on solid substrates such as soils and rocks. New generation fluorescent dyes that bind specifically to DNA, RNA and proteins allow simple and rapid estimates of these biomolecules in crude environmental samples.

PRACTICAL APPLICATIONS

Monitoring the metabolic state of microbial communities on different substrates and environments is a requirement for comparing samples and assessing the participation of microorganisms in a variety of processes. Solid substrates are not easily analyzed by microscopic techniques and they require long processing times and tedious work. Aside from this, only a minor fraction (<1%) of microorganisms in most natural environments can be cultured in standard microbiological media ( Ward et al. 1990 ). Other studies using incorporation of labeled substrates to approach activity rates or biomolecule extractions represent complex and long procedures during environmental studies.In order to evaluate microbial communities in a variety of substrates and environments, rapid and simple methods are proposed by measuring DNA, RNA and/or proteins using specific fluorescent dyes, without a need for prior purification, from crude solid samples.     

Micropropagation of three berry fruit species using nodal segments from field-grown plants

Plant micropropagation of blueberry (Vaccinium corymbosum L. cv. Berkeley), blackberry (Rubus sp. cv. Smoothstem) and raspberry (Rubus idaeus L. cv. Gradina) was carried out from nodal segments of adult field‐grown plants. Hardwood and softwood cuttings were studied as explant sources. The cultures successfully established were softwood from all three species, and hardwood only from blueberry. Shoot‐bud establishment from blueberry was achieved by culturing explants in WPM salts with MS vitamins for 15 days, and then 30 days in the same medium with 18 mM Zeatin. The best results of multiplication were obtained in the same medium with 25 mM 2iP. For blackberry, shoot‐bud establishment was achieved by culturing explants in MS medium for 15 days, and then in the same medium with 4 mM BA and 0.25 mM IBA. This medium was also the best for blackberry multiplication. Raspberry explants (cvs Gradina and Willamette) were cultured in MS medium for 15 days and then transferred to MS medium supplemented with 4 μm BA and 0.25 mM IBA. After 30 days of culture, only ‘Gradina’ explants survived, from which shoot‐bud establishment was obtained in a modified MS medium (Anderson's macronutrients except calcium, with Sequestrene as the iron source) with the same growth regulators. Multiplication was achieved by subculturing explants in the same medium either with 4 mM BA plus 0.25 mM IBA or with 8 mM BA plus 0.25 mM IBA. Shoots of at least 1 cm in length from all species were rooted ex vitro in a mixture of peat and Perlite (1:1, v/v) in a mist chamber, and 100% of rooting plants were acclimated. Bacterial, fungal and viral diseases were detected in stock plants, while tests carried out in both shoots and regenerated plants revealed the absence of any kind of disease.     

Approaches in extracellular matrix engineering for determination of adhesion molecule mediated single cell function

The native extracellular matrix (ECM) and the cells that comprise human tissues are together engaged in a complex relationship; cells alter the composition and structure of the ECM to regulate the material and biologic properties of the surrounding environment while the composition and structure of the ECM modulates cellular processes that maintain healthy tissue and repair diseased tissue. This reciprocal relationship occurs via cell adhesion molecules (CAMs) such as integrins, selectins, cadherins and IgSF adhesion molecules. To study these cell-ECM interactions, researchers use two-dimensional substrates or three-dimensional matrices composed of native proteins or bioactive peptide sequences to study single cell function. While two-dimensional substrates provide valuable information about cell-ECM interactions, three-dimensional matrices more closely mimic the native ECM; cells cultured in three-dimensional matrices have demonstrated greater cell movement and increased integrin expression when compared to cells cultured on two-dimensional substrates. In this article we review a number of cellular processes (adhesion, motility, phagocytosis, differentiation and survival) and examine the cell adhesion molecules and ECM proteins (or bioactive peptide sequences) that mediate cell functionality.