Correlation of growth inhibition with accumulation of Pb in cell wall and changes in response to oxidative stress in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> seedlings

Uptake of the non-essential element, lead (Pb), by 7-days-old Arabidopsis thaliana seedlings caused inhibition of root growth. Pb accumulated mainly in the root and only a small proportion of the total uptake was transported to the shoot. At the ultrastructural level, Pb was localized mainly in the cell walls, intercellular spaces and vacuoles, which may serve to minimize Pb toxicity to vital functions of the cytosol. Pb exposure induced the generation of reactive oxygen species (ROS) and increased the level of lipid hydroperoxide. These changes were accompanied by up-regulation of the activities of antioxidative enzymes in a dose-dependent manner. Although no major destructive changes to the cytoplasm and vital organelles were observed, it is postulated that at least part of the cost of Pb exposure to A. thaliana seedlings is reflected in reduced root growth associated with increased free radical production by cell wall-accumulated Pb.     

Practical and reliable FRET/FLIM pair of fluorescent proteins

Background  

In spite of a great number of monomeric fluorescent proteins developed in the recent years, the reported fluorescent protein-based FRET pairs are still characterized by a number of disadvantageous features, complicating their use as reporters in cell biology and for high-throughput cell-based screenings.     

Morphological changes of the optic lobe from late embryonic to adult stages in oval squids Sepioteuthis lessoniana

The optic lobe is the largest brain area within the central nervous system of cephalopods and it plays important roles in the processing of visual information, the regulation of body patterning, and locomotive behavior. The oval squid Sepioteuthis lessoniana has relatively large optic lobes that are responsible for visual communication via dynamic body patterning. It has been observed that the visual behaviors of oval squids change as the animals mature, yet little is known about how the structure of the optic lobes changes during development. The aim of the present study was to characterize the ontogenetic changes in neural organization of the optic lobes of S. lessoniana from late embryonic stage to adulthood. Magnetic resonance imaging and micro‐CT scans were acquired to reconstruct the 3D‐structure of the optic lobes and examine the external morphology at different developmental stages. In addition, optic lobe slices with nuclear staining were used to reveal changes in the internal morphology throughout development. As oval squids mature, the proportion of the brain making up the optic lobes increases continuously, and the optic lobes appear to have a prominent dent on the ventrolateral side. Inside the optic lobe, the cortex and the medulla expand steadily from the late embryonic stage to adulthood, but the cell islands in the tangential zone of the optic lobe decrease continuously in parallel. Interestingly, the size of the nuclei of cells within the medulla of the optic lobe increases throughout development. These findings suggest that the optic lobe undergoes continuous external morphological change and internal neural reorganization throughout the oval squid's development. These morphological changes in the optic lobe are likely to be responsible for changes in the visuomotor behavior of oval squids from hatching to adulthood.     

Stable coexistence of two <Emphasis Type="Italic">Caldicellulosiruptor</Emphasis> species in a <Emphasis Type="Italic">de novo</Emphasis> constructed hydrogen-producing co-culture

Background  

Mixed culture enrichments have been used frequently for biohydrogen production from different feedstock. In spite of the several advantages offered by those cultures, they suffer poor H₂ yield. Constructing defined co-cultures of known H₂ producers may offer a better performance than mixed-population enrichments, while overcoming some of the limitations of pure cultures based on synergies among the microorganisms involved.