Did tRNA synthetase classes arise on opposite strands of the same gene?

Structural homology of class II aminoacyl-tRNA synthetases to the HSP70 family and the existence of a gene whose sense and antisense strands code for a dehydrogenase and an HSP70 chaperonin justify reconsideration of a possible sense-antisense ancestry for the two synthetase classes.     

Heterogeneous populations of bone marrow stem cells--are we spotting on the same cells from the different angles?

Accumulated evidence suggests that in addition to hematopoietic stem cells (HSC), bone marrow (BM) also harbors endothelial stem cells (ESC), mesenchymal stem cells (MSC), multipotential adult progenitor cells (MAPC), pluripotent stem cells (PCS) as well as tissue committed stem cells (TCSC) recently identified by us. In this review we discuss the similarities and differences between these cell populations. Furthermore, we will present the hypothesis that all of these versatile BM derived stem cells are in fact different subpopulations of TCSC. These cells accumulate in bone marrow during ontogenesis and being a mobile population of cells are released from BM into peripheral blood after tissue injury to regenerate damaged organs. Furthermore, since BM is a "hideout" for TCSC, their presence in preparations of bone marrow derived mononuclear cells should be considered before experimental evidence is interpreted simply as trans-differentiation or plasticity of HSC. Finally, our observation that the number of TCSC accumulate in the bone marrow of young animals and their numbers decrease during senescence provides a new insight into aging and may explain why the regeneration processes becomes less effective in older individuals.     

Do distantly related parasites rely on the same proximate factors to alter the behaviour of their hosts?

Phylogenetically unrelated parasites often increase the chances of their transmission by inducing similar phenotypic changes in their hosts. However, it is not known whether these convergent strategies rely on the same biochemical precursors. In this paper, we explored such aspects by studying two gammarid species (Gammarus insensibilis and Gammarus pulex; Crustacea: Amphipoda: Gammaridae) serving as intermediate hosts in the life cycle of two distantly related parasites: the trematode, Microphallus papillorobustus and the acanthocephalan, Polymorphus minutus. Both these parasite species are known to manipulate the behaviour of their amphipod hosts, bringing them towards the water surface, where they are preferentially eaten by aquatic birds (definitive hosts). By studying and comparing the brains of infected G. insensibilis and G. pulex with proteomics tools, we have elucidated some of the proximate causes involved in the parasite-induced alterations of host behaviour for each system. Protein identifications suggest that altered physiological compartments in hosts can be similar (e.g. immunoneural connexions) or different (e.g. vision process), and hence specific to the host-parasite association considered. Moreover, proteins required to alter the same physiological compartment can be specific or conversely common in both systems, illustrating in the latter case a molecular convergence in the proximate mechanisms of manipulation.     

Impact of gut-associated bifidobacteria and their phages on health: two sides of the same coin?

Applied Microbiology and Biotechnology - Bifidobacteria are among the first microbial colonisers of the human infant gut post-partum. Their early appearance and dominance in the human infant gut...     

The effect of historical legacy on adaptation: do closely related species respond to the environment in the same way?

The many documented examples of parallel and convergent evolution in similar environments are strong evidence for the role of natural selection in the evolution of trait variation. However, species may respond to selection in different ways; idiosyncrasies of their evolutionary history may affect how different species respond to the same selective pressure. To determine whether evolutionary history affects trait-environment associations in a recently diverged lineage, we investigated within-species trait-environment associations in the white proteas, a closely related monophyletic group. We first used manovas to determine the relative importance of shared response to selection, evolutionary history and unique responses to selection on trait variation. We found that on average, similar associations to the environment across species explained trait variation, but that the species had different mean trait values. We also detected species-specific associations of traits with the environmental gradients. To identify the traits associated uniquely with the environment, we used a structural equation model. Our analysis showed that the species differed in how their traits were associated with each of the environmental variables. Further, in the cases of two root traits (root mass and root length/mass ratio), two species differed in the direction of their associations (e.g. populations in one species had heavier roots in warmer areas, and populations in the other species had lighter roots in warmer areas). Our study shows that even in a closely related group of species, evolutionary history may have an effect on both the size and direction of adaptations to the environment.     

Does a polyphagous caterpillar have the same gut microbiota when feeding on different species of food plants?

We used classical culture techniques to explore gut bacteria and changes associated with dietary change in the highly polyphagous, tropical caterpillar Automeris zugana (Saturniidae). Fifty-five third instar wild-caught sibs feeding on Annona purpurea (Annonaceae) in the Area de Conservación Guanacaste (ACG) in northwestern Costa Rica were divided into eight groups. Each of seven groups was reared to the ultimate instar on another species of food plant normally used by A. zugana. Some pupae were also analyzed for the presence of bacteria. Aerobic bacterial cultures were obtained from all 33 caterpillar guts and the eight pupae inventoried. There was no clear pattern in species composition of cultivated bacteria among the eight diets, and each caterpillar on a given food plant carried only a small fraction of the total set of species isolated from the set of caterpillars feeding on that food plant. Taken as a whole, the larvae and pupae contained 22 species of cultivable bacteria in 12 genera. Enterobacter, present in 81.8% of the samples, was the genus most frequently isolated from the caterpillars, followed by Micrococcus and Bacillus. Bacillus thuringiensis was isolated from 30.3% of the dissected caterpillars, but found in caterpillars feeding on only half of the species of food plants.     

Does the Spanish version of the SWLS measure the same in Spain and Peru?

AimSatisfaction with life is a measure of protection in older adults. There lies the importance of providing quality instruments. The aim of the study was to evaluate the invariance of the life satisfaction scale (SWLS) in two samples of older adults in Spain and Peru.MethodThe participants were 857 older adults in Spain (mean age = 68.23 years, SD = 5.93) and 336 older adults in Peru (average age = 72.42, SD = 7.07). All multi-group confirmatory factor analyzes were estimated in Mplus 8.0.ResultsThe results indicate the presence of a strict invariance of the one-dimensional structure of the SWLS in samples of older adults in Spain and Peru, which allows for meaningful comparisons of latent means and covariances. Comparison of latent means showed small differences in the construct between the cultural groups.ConclusionsThe SWLS is a valid instrument for intercultural comparisons between Spanish and Peruvian population. The measurement invariance assessment contributes to a better understanding of life satisfaction in populations from different cultural contexts.     

Viruses and autoimmune disease--two sides of the same coin?

Some viruses have the ability to modulate the development of autoimmune diseases. Virus infections have long been associated with the exacerbation of autoimmune disease, however, there is also evidence that viruses can actually protect against autoimmune disease. Several experimental models have been developed to investigate how some virus infections can prime for and trigger autoimmunity whereas others ameliorate the pathway leading to clinical disease. It is possible that the type I interferons, via interleukin 12, provide the link between viruses and autoimmunity.     

Do gymnosperm needles pull water through the xylem produced in the same year as the needle?

This research investigated the longevity of functional connections between leaf traces and stem xylem in 16 species of conifers to better understand the spatial use of sapwood for water transport. The first question was which ring(s) stained when a vacuum was applied to the distal end of the cut surface of a needle attached to a short stem segment. The vacuum was applied to either 1- or 2-yr-old foliage taken from 4-6-yr-old saplings. The 16 species were then categorized based on the growth ring that most consistently stained when the vacuum was applied to the 2-yr-old needles. There were three distinct stain patterns for the evergreen conifers and one pattern for the deciduous conifers. Three evergreen species could not be categorized. The second question used needle fall data to ask whether the leaf trace appeared to break because of age or stem diameter in 5-yr-old Pseudotsuga menziesii saplings. An apparent threshold stem diameter at which needles tended to be shed was more related to diameter than age. These xylem connection patterns could affect leaf cohort physiology and the spatial pattern of water flux in sapwood.     

Tired of the same old grind in the new genomics and proteomics era?

New discoveries in life sciences depend on accurate analysis of biomolecules, which in turn depends on the extraction of high-quality molecules in high quantities from the tissues of plants, animals or microorganisms. The extraction process for hard-to-lyse cells and tissues has been a bottleneck in the path to discovery for many years. This review describes extraction methods currently in use, and compares them to a newly developed, automated process involving patented pressure cycling technology (PCT). The PCT sample preparation system (SPS) uses an instrument capable of rapid, temperature-controlled pressure cycling between ambient and high pressures, and single-use sample tubes containing a ram and a lysis disk. The quality and quantity of nucleic acid and protein prepared by the PCT SPS method are comparable to the older methods, whereas ease and safety of processing, reproducibility, speed and control are enhanced.