A new source of endothelial progenitor cells--vascular biology redefined?

The initial discovery of endothelial progenitor cells (EPCs) in tandem with emerging concepts in stem cell biology has generated enormous interest and excitement in fields as diverse as tissue engineering, regenerative medicine, and tumor and vascular biology. A recent paper by Ingram et al. identifies a complete hierarchy of EPCs in the vessel wall, providing a new framework for classification of cells supporting endopoiesis akin to that previously established for hematopoiesis. This could have fundamental implications for our understanding of the role of the endothelium and, more specifically, the role of EPC interfacing with the vessel wall in health and disease.     

Ectomycorrhizal fungi: A new source of atmospheric methyl halides?

Incomplete source budgets for methyl halides – compounds that release inorganic chlorine and bromine radicals which, in turn, catalyze atmospheric ozone depletion – limit our ability to predict the fate of the stratospheric ozone layer. We report here the first measured emissions of methyl chloride, methyl bromide, and methyl iodide from ectomycorrhizal fungi. We grew nine fungal isolates on growth media containing halide concentrations similar to those found in soils and plant tissues. The observed range of emissions was 0.003–65 μg methyl chloride, 0.001–3 μg methyl bromide, and 0.02–12 μg methyl iodide g^?1 dry weight fungi day^?1. Species varied in production rates of methyl chloride vs. methyl bromide vs. methyl iodide. Cenococcum geophilum, a widespread ectomycorrhizal fungus, was further tested to investigate the effects of halide substrate concentration in growth media. Emissions from this species increased linearly with increasing concentrations of both bromide and iodide. In addition, a subset of four fungi was studied with two media concentrations each of chloride, bromide, and iodide (0.2 or 20 mm ). These fungi had similar responses to halide concentration, despite 1000‐fold differences in baseline emission rates between isolates. Finally, high chloride concentrations (20 mm ) in media did not appear to inhibit emissions of methyl bromide or methyl iodide. Overall, ectomycorrhizal fungi might be an important source of methyl halides to the atmosphere, and substrate concentrations and community composition may influence production levels in ecosystems.     

Temporal instability of isotopes–climate statistical relationships – A study of black spruce trees in northeastern Canada

Climate reconstructions using stable isotopes (δ¹⁸O and δ¹³C values) in tree rings are based on relationships between present climatic conditions and isotopic series. This widely used approach relies on the assumption that correlations between stable isotopes and climatic conditions are steady over time. In this paper, we evaluate the strength of the correlations between δ¹⁸O and δ¹³C series with several climatic parameters on fourteen black spruce trees coming from three different sites, in northeastern Canada. We applied a 21-year moving window on the r Pearson calculated between stable isotopes and March–May and June–August precipitation, June–August and April–June maximal temperatures. Our results indicate that despite the large distance and differences in stand conditions between the sites, the three sites responded in the same way over time. We show that because the climatic ambiance has changed during the 1980–1990 period due to a positive North Atlantic Oscillation index the δ¹³C values are not controlled anymore by spring precipitation or summer maximal temperature in the following two decades. As opposed to δ¹³C series, the relationship between summer maximal temperature and δ¹⁸O values was stable over time, and decreased only in the last decade. All these results attest of a “divergence problem” in the last decades which is most pronounced for δ¹³C series. We conclude that the spruce δ¹⁸O series appears to be the most appropriate indicator for reconstructing June–August maximal temperature in the studied area despite the divergence issue, given that the calibration–validation tests and reconstruction can exclude the divergent last decade.     

Are chlorella viruses a rich source of ion channel genes?

Plaque-forming dsDNA (>330 kb) viruses that infect certain unicellular, eukaryotic chlorella-like green algae contain approximately 375 protein-encoding genes. These proteins include a 94 amino acid K+ channel protein, called Kcv, as well as two putative ligand-gated ion channels. The viruses also encode other proteins that could be involved in the assembly and/or function of ion channels, including protein kinases and a phosphatase, polyamine biosynthetic enzymes and histamine decarboxylase.     

Deep-sea hydrothermal vents: A new source of innovative bacterial exopolysaccharides of biotechnological interest?

Polysaccharides and, in particular, microbial polysaccharides represent a class of important products of growing interest for many sectors of industry. Although many known marine bacteria produce exopolysaccharides (EPS), continuation in looking for new polysaccharide-producing microorganisms is promising. Hydrothermal deep-sea vents could be a source of novel EPS as indicated by the screening of a number of mesophilic heterotrophic bacteria recovered from different locations. Although originating from such extreme environment, some bacteria were shown to biosynthesize innovative EPS under laboratory conditions. Their specific rheological properties either in the presence or absence of monovalent and divalent ions, biological activities, metal binding capabilities, and novel chemical composition mean that these EPS are expected to find many applications in the near future. Journal of Industrial Microbiology & Biotechnology (2002) 29, 204–208 doi:10.1038/sj.jim.7000298 Received 18 March 2002/ Accepted in revised form 13 June 2002     

Biochemical prevention and treatment of viral infections – A new paradigm in medicine for infectious diseases

For two centuries, vaccination has been the dominating approach to develop prophylaxis against viral infections through immunological prevention. However, vaccines are not always possible to make, are ineffective for many viral infections, and also carry certain risk for a small, yet significant portion of the population. In the recent years, FDA's approval and subsequent market acceptance of Synagis, a monoclonal antibody indicated for prevention and treatment of respiratory syncytial virus (RSV) has heralded a new era for viral infection prevention and treatment. This emerging paradigm, herein designated "Biochemical Prevention and Treatment", currently involves two aspects: (1) preventing viral entry via passive transfer of specific protein-based anti-viral molecules or host cell receptor blockers; (2) inhibiting viral amplification by targeting the viral mRNA with anti-sense DNA, ribozyme, or RNA interference (RNAi). This article summarizes the current status of this field.     

ROXAS – A new tool to build centuries-long tracheid-lumen chronologies in conifers

Measurements of tree-ring features (ring width, density, isotopes concentration, etc.) are well-established proxies of environmental variability and, in particular, climate fluctuation at local, regional and continental scales. In recent years, tree-ring anatomical structure (conduit size, density, cell wall thickness, ray abundance, etc.) has been recognized as a novel source of valuable ecological information. However, despite the high potential interest, these kinds of investigations have been significantly constrained by the methodological limitations and time-consuming procedures of data collection.In this paper, we present ROXAS: an image analysis tool specifically designed to automatically recognize and measure conduit lumen area and calculate reliable statistics in a reasonable amount of time. With ROXAS, many of the aforementioned limitations in analyzing tree-ring anatomical structure can potentially be overcome. While ROXAS was previously used exclusively for angiosperm analysis, we demonstrate in this paper for the first time how it can also be used to analyze an entire sample of a conifer wood.The use of ROXAS for the analysis of conifer anatomy is exemplified by a 120-year long Pinus leucodermis sample including about 75,000 tracheid cells. The results of ROXAS fully automatic tracheid detection are compared to the results obtained after using in-built manual editing capabilities. While both approaches proved to be efficient, the quality of the fully automatic tracheid detection is found to be generally sufficient for most research applications.     

Characterization of the effects of inter-tree competition on source–sink balance in Chinese pine trees with the GreenLab model

We investigate the characteristics of individual tree response to competition on source–sink balance through the functional–structural plant model GreenLab. Four Chinese pine (Pinus tabulaeformis Carr.) trees were destructively sampled and were divided into two groups: high-density group and low-density group. First, the effects of density on organ dimensions and on organ relative mass were analysed based on experimental measurements. These were primary indicators of the plant response to competition. Second, the hidden parameters of the GreenLab model, as well as a tree-specific characteristic surface, were estimated using the data of total tree biomass for needle and wood compartments, for each of the four trees in parallel. The quality of the fitting is finally validated using data of individual organ mass at shoot level for the sampled branches. The Mann–Whitney Student’s t test showed that there were significant differences between the shoot attributes of the two groups for shoot diameter, shoot biomass and needle biomass. No significant difference was found for current year shoot lengths of the two groups. The parametric identification of the model allowed estimating and comparing the amount of biomass that was allocated to primary growth and to secondary growth in the two density conditions. It showed that biomass allocated to secondary growth (ring compartment) was the most strongly affected by density, and that the organ demand satisfaction ratio profiles of each of these trees were a relevant, integrated indicator of the tree state.     

Biomass as source of chemicals VII — Synthesis of new oxiranes

Application of a solid-liquid phase transfer technique in low hydrated organic medium makes the synthesis of the corresponding oxiranes possible for the first time. These new molecules, obtained from biomass, can be applied in many different ways in macromolecular chemistry.     

A valid assessment of students’ skill in determining relationships on evolutionary trees

Background

Evolutionary trees illustrate relationships among taxa. Interpreting these relationships requires developing a set of “tree-thinking” skills that are typically included in introductory college biology courses. One of these skills is determining relationships among taxa using the most recent common ancestor, yet many students instead use one or more alternate strategies to determine relationships. Several alternate strategies have been well documented and these include using superficial similarity, proximity at the tips of a tree, or the fewest intervening nodes in the tree to group taxa.

Results

We administered interviews (n = 16) and pencil-and-paper questionnaires (n = 205), and constructed a valid and reliable assessment that measured how well students determined relationships among taxa on an evolutionary tree. Our questions asked students to consider a focal taxon and identify which of two additional taxa is most closely related to it. We paired the use of most recent common ancestor with one of three alternative strategies (i.e., similarity, proximity, or node-counting) to explicitly test students’ understanding of the relationships among the taxa on each tree.

Conclusions

Our assessment enables us to identify students who are effectively distracted by an alternative strategy, those who use the most recent common ancestor inconsistently, or who are guessing in order to determine relationships among taxa. Our 18-question tool (see Additional file 1) can be used for formative assessment of student understanding of how to interpret relationships on evolutionary trees. Because our assessment tests for the same skill throughout, students who answer incorrectly, even once, likely have an incomplete understanding of how to determine relationships on evolutionary trees and should receive follow-up instruction.

     

Ant-cultivated Chaetothyriales in hollow stems of myrmecophytic Cecropia sp. trees – diversity and patterns

Five Cecropia tree species occupied by four Azteca ant species from Costa Rica and French Guiana were investigated to assess the diversity and host specificity of chaetothyrialean fungal symbionts. The ITS rDNA region of the symbiotic fungi was sequenced either from pure culture isolation, or from environmental samples obtained from ant colonies nesting in hollow stems of the Cecropia host plants. The investigation revealed six closely related OTUs of Chaetothyriales. Neither the four Azteca species nor the six fungal OTUs were associated with specific Cecropia species. In contrast, ants and fungi showed an association. Azteca alfari was associated with a particular OTU, and often contained only one. Azteca coeruleipennis, Azteca constructor and Azteca xanthochroa were associated with a different set of OTUs and often had multiple OTUs within colonies. Possible reasons for these differences and the role of the fungi for the Azteca-Cecropia symbiosis are discussed.     

Quantitative analysis of anthropogenic influences on coastal water – A new perspective

Coastal environment has been disturbed by human activities for a long time, especially in the rapidly urbanizing and industrializing areas. Although the surrounding area has achieved great economic success in the past 30 years, Western Xiamen Bay (China) is seriously affected by pollutants and is facing increasing ecological pressure. Because of this, Xiamen was selected in 1994 as a demonstration site for implementing an integrated coastal management program, which included a series of measures for protecting the coastal environment. However, coastal environment is dynamic, complex and site-specific, and thus a scientific quantitative evaluation framework is necessary for environment quality analysis and effective coastal management. In this study, we used oceanographic knowledge together with quantitative methods (Bai-Perron's structural break test) to analyze the long-term variations of water quality indices (pH, DO, COD, DIN, PO₄-P and Oil) in Western Xiamen Bay. In addition, we compared with other coastal areas to identify the effectiveness of phosphorus-based nutrient management measures and predicted the probable variation trend in the future. The results show that in Western Xiamen Bay: (1) the concentrations of DO and Oil in seawater are effectively controlled by local coastal management measures; (2) seawater acidification will continue to worsen based on the present situation; and (3) the P-limitation treatment strategies are effective and PO₄-P concentration starts to fall according to the multiple statistical analysis and Environmental Kuznets Curve. This paper hopes to provide an epitome of the conflicts and consolations between socioeconomic development and environmental quality in the past, and hints for coastal management in the future.     

Caranday—A source of palm wax

Millions of these palm trees in the Gran Chaco of central South America, occupying parts of Argentina, Bolivia and Paraguay, offer an unexploited commercial source of a hard vegetable wax, potentially as great as that of carnauba palm in northeastern Brazil.     

Canaigre—A desert source of tannin

Canaigre has been in use on a limited scale as a source of tannin for about 100 years. It is easily grown, requires no special attention, and may be the answer to shortages in natural tannin supplies.     

The use of charcoal in in vitro culture – A review

Activated charcoal is commonly used in tissue culture media. Its addition to culture medium may promote or inhibit in vitro growth, depending on species and tissues used. The effects of activated charcoal may be attributed to establishing a darkened environment; adsorption of undesirable/inhibitory substances; adsorption of growth regulators and other organic compounds, or the release of growth promoting substances present in or adsorbed by activated charcoal.