More widespread alien tree species do not have larger impacts on regeneration of native tree species in a tropical forest reserve

There is insufficient information regarding the factors affecting the environmental impacts of alien species. In particular, little is known about whether there is any relationship between the invasiveness (establishment and spread) of an introduced species and its per capita impact. We experimentally assessed the relationship between the extent of spread of up to 29 alien plant species and their impact on recruitment of native tree species in Amani Botanical Garden, Tanzania. We also studied the effects of allelochemicals of selected alien on native plant species to assess potential mechanisms of impact. We found no relationship between the extent of spread of an alien tree species and their impact on seed germination, seedling survival, and seedling communities of native trees in their understory, and no indication that allelochemicals consistently explain their effects on recruitment of the studied species. These results suggest that extent of spread cannot be used as a proxy for impact. Hence, managers should continue assessing both the spread and the impact of alien species when prioritizing alien species for management.     

A rapid, sensitive, and selective bioluminescence resonance energy transfer (BRET)-based nucleic acid sensing system

Here we report the design of a bioluminescence resonance energy transfer (BRET)-based sensing system that could detect nucleic acid target in 5 min with high sensitivity and selectivity. The sensing system is based on adjacent binding of oligonucleotide probes labeled with Renilla luciferase (Rluc) and quantum dot (Qd) on the nucleic acid target. Here Rluc, a bioluminescent protein that generates light by a chemical reaction, is employed as an energy donor, and a quantum dot is used as an energy acceptor. Bioluminescence emission of Rluc overlaps with the Qd absorption whereas the emission of Qd is shifted from the emission of Rluc allowing for monitoring of BRET. In the presence of target, the labeled probes bind adjacently in a head-to-head fashion leading to BRET from Rluc to Qd upon addition of a substrate coelenterazine. The sensing system could detect target nucleic acid in buffer as well as in Escherichia coli cellular matrix in 5 min with a detection limit of 0.54 pmol. The ability to detect target nucleic acid rapidly in a cellular matrix with high sensitivity will prove highly beneficial in biomedical and environmental applications.     

The selector gene cut represses a neural cell fate that is specified independently of the Achaete-Scute-Complex and atonal.

The peripheral nervous system (PNS) of Drosophila offers a powerful system to precisely identify individual cells and dissect their genetic pathways of development. The mode of specification of a subset of larval PNS cells, the multiple dendritic (md) neurons (or type II neurons), is complex and still poorly understood. Within the dorsal thoracic and abdominal segments, two md neurons, dbd and dda1, apparently require the proneural gene amos but not atonal (ato) or Achaete-Scute-Complex (ASC) genes. ASC normally acts via the neural selector gene cut to specify appropriate sensory organ identities. Here, we show that dbd- and dda1-type differentiation is suppressed by cut in dorsal ASC-dependent md neurons. Thus, cut is not only required to promote an ASC-dependent mode of differentiation, but also represses an ASC- and ato-independent fate that leads to dbd and dda1 differentiation.     

Analysis of microRNA expression by in situ hybridization with RNA oligonucleotide probes

In situ hybridization is an important tool for analyzing gene expression and developing hypotheses about gene functions. The discovery of hundreds of microRNA (miRNA) genes in animals has provided new challenges for analyzing gene expression and functions. The small size of the mature miRNAs ( approximately 20-24 nucleotides in length) presents difficulties for conventional in situ hybridization methods. However, we have described a modified in situ hybridization method for detection of mammalian miRNAs in tissue sections, based upon the use of RNA oligonucleotide probes in combination with highly specific wash conditions. Here, we present detailed procedures for detection of miRNAs in tissue sections or cultured cells. The methods described can utilize either nonradioactive hapten-conjugated probes that are detected by enzyme-coupled antibodies, or radioactively labeled probes that are detected by autoradiography. The ability to visualize miRNA expression patterns in tissue sections provides an additional tool for the analyses of miRNA expression and function. In addition, the use of radioactively labeled probes should facilitate quantitative analyses of changes in miRNA gene expression.     

Role of saturated and unsaturated fatty acids on dicarbonyl–albumin derived advanced glycation end products in vitro

Amino Acids - Glycation is a non-enzymatic reaction that occurs between the free amino group of proteins and reducing sugars and/or lipids, leading to the formation of advanced glycation end...     

EphA2 Receptor Unliganded Dimers Suppress EphA2 Pro-tumorigenic Signaling

The EphA2 receptor tyrosine kinase promotes cell migration and cancer malignancy through a ligand- and kinase-independent distinctive mechanism that has been linked to high Ser-897 phosphorylation and low tyrosine phosphorylation. Here, we demonstrate that EphA2 forms dimers in the plasma membrane of HEK293T cells in the absence of ephrin ligand binding, suggesting that the current seeding mechanism model of EphA2 activation is incomplete. We also characterize a dimerization-deficient EphA2 mutant that shows enhanced ability to promote cell migration, concomitant with increased Ser-897 phosphorylation and decreased tyrosine phosphorylation compared with EphA2 wild type. Our data reveal a correlation between unliganded dimerization and tumorigenic signaling and suggest that EphA2 pro-tumorigenic activity is mediated by the EphA2 monomer. Thus, a therapeutic strategy that aims at the stabilization of EphA2 dimers may be beneficial for the treatment of cancers linked to EphA2 overexpression.